diff --git a/Tethering/Android.bp b/Tethering/Android.bp
new file mode 100644
index 0000000..5526c65
--- /dev/null
+++ b/Tethering/Android.bp
@@ -0,0 +1,137 @@
+//
+// Copyright (C) 2019 The Android Open Source Project
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//      http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+//
+
+java_defaults {
+    name: "TetheringAndroidLibraryDefaults",
+    sdk_version: "module_current",
+    srcs: [
+        "src/**/*.java",
+        ":framework-tethering-shared-srcs",
+        ":tethering-module-utils-srcs",
+        ":services-tethering-shared-srcs",
+    ],
+    static_libs: [
+        "androidx.annotation_annotation",
+        "netd_aidl_interface-unstable-java",
+        "netlink-client",
+        // TODO: use networkstack-client instead of just including the AIDL interface
+        "networkstack-aidl-interfaces-unstable-java",
+        "android.hardware.tetheroffload.config-V1.0-java",
+        "android.hardware.tetheroffload.control-V1.0-java",
+        "net-utils-framework-common",
+        "net-utils-device-common",
+    ],
+    libs: [
+        "framework-statsd.stubs.module_lib",
+        "framework-tethering.impl",
+        "framework-wifi",
+        "unsupportedappusage",
+    ],
+    plugins: ["java_api_finder"],
+    manifest: "AndroidManifestBase.xml",
+}
+
+// Build tethering static library, used to compile both variants of the tethering.
+android_library {
+    name: "TetheringApiCurrentLib",
+    defaults: ["TetheringAndroidLibraryDefaults"],
+}
+
+// Due to b/143733063, APK can't access a jni lib that is in APEX (but not in the APK).
+cc_library {
+    name: "libtetherutilsjni",
+    sdk_version: "current",
+    apex_available: [
+        "//apex_available:platform", // Used by InProcessTethering
+        "com.android.tethering",
+    ],
+    min_sdk_version: "current",
+    srcs: [
+        "jni/android_net_util_TetheringUtils.cpp",
+    ],
+    shared_libs: [
+        "liblog",
+        "libnativehelper_compat_libc++",
+    ],
+
+    // We cannot use plain "libc++" here to link libc++ dynamically because it results in:
+    //   java.lang.UnsatisfiedLinkError: dlopen failed: library "libc++_shared.so" not found
+    // even if "libc++" is added into jni_libs below. Adding "libc++_shared" into jni_libs doesn't
+    // build because soong complains of:
+    //   module Tethering missing dependencies: libc++_shared
+    //
+    // So, link libc++ statically. This means that we also need to ensure that all the C++ libraries
+    // we depend on do not dynamically link libc++. This is currently the case, because liblog is
+    // C-only and libnativehelper_compat_libc also uses stl: "c++_static".
+    stl: "c++_static",
+
+    cflags: [
+        "-Wall",
+        "-Werror",
+        "-Wno-unused-parameter",
+        "-Wthread-safety",
+    ],
+
+    ldflags: ["-Wl,--exclude-libs=ALL,-error-limit=0"],
+}
+
+// Common defaults for compiling the actual APK.
+java_defaults {
+    name: "TetheringAppDefaults",
+    sdk_version: "module_current",
+    privileged: true,
+    jni_libs: [
+        "libtetherutilsjni",
+    ],
+    resource_dirs: [
+        "res",
+    ],
+    libs: [
+        "framework-tethering",
+        "framework-wifi",
+    ],
+    jarjar_rules: "jarjar-rules.txt",
+    optimize: {
+        proguard_flags_files: ["proguard.flags"],
+    },
+}
+
+// Non-updatable tethering running in the system server process for devices not using the module
+android_app {
+    name: "InProcessTethering",
+    defaults: ["TetheringAppDefaults"],
+    static_libs: ["TetheringApiCurrentLib"],
+    certificate: "platform",
+    manifest: "AndroidManifest_InProcess.xml",
+    // InProcessTethering is a replacement for Tethering
+    overrides: ["Tethering"],
+    apex_available: ["com.android.tethering"],
+    min_sdk_version: "current",
+}
+
+// Updatable tethering packaged as an application
+android_app {
+    name: "Tethering",
+    defaults: ["TetheringAppDefaults"],
+    static_libs: ["TetheringApiCurrentLib"],
+    certificate: "networkstack",
+    manifest: "AndroidManifest.xml",
+    use_embedded_native_libs: true,
+    // The permission configuration *must* be included to ensure security of the device
+    required: ["NetworkPermissionConfig"],
+    apex_available: ["com.android.tethering"],
+    min_sdk_version: "current",
+}
diff --git a/Tethering/AndroidManifest.xml b/Tethering/AndroidManifest.xml
new file mode 100644
index 0000000..e6444f3
--- /dev/null
+++ b/Tethering/AndroidManifest.xml
@@ -0,0 +1,57 @@
+<?xml version="1.0" encoding="utf-8"?>
+<!--
+/*
+ * Copyright (C) 2019 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+-->
+<manifest xmlns:android="http://schemas.android.com/apk/res/android"
+          package="com.android.networkstack.tethering"
+          android:sharedUserId="android.uid.networkstack">
+    <uses-sdk android:minSdkVersion="29" android:targetSdkVersion="29" />
+
+    <!-- Permissions must be defined here, and not in the base manifest, as the tethering
+         running in the system server process does not need any permission, and having
+         privileged permissions added would cause crashes on startup unless they are also
+         added to the privileged permissions allowlist for that package. -->
+    <uses-permission android:name="android.permission.ACCESS_NETWORK_STATE" />
+    <uses-permission android:name="android.permission.BLUETOOTH" />
+    <uses-permission android:name="android.permission.BLUETOOTH_PRIVILEGED" />
+    <uses-permission android:name="android.permission.BROADCAST_STICKY" />
+    <uses-permission android:name="android.permission.CHANGE_NETWORK_STATE" />
+    <uses-permission android:name="android.permission.MANAGE_USB" />
+    <uses-permission android:name="android.permission.MODIFY_PHONE_STATE" />
+    <uses-permission android:name="android.permission.READ_DEVICE_CONFIG" />
+    <uses-permission android:name="android.permission.READ_NETWORK_USAGE_HISTORY" />
+    <uses-permission android:name="android.permission.READ_PHONE_STATE"/>
+    <uses-permission android:name="android.permission.TETHER_PRIVILEGED" />
+    <uses-permission android:name="android.permission.UPDATE_APP_OPS_STATS" />
+    <uses-permission android:name="android.permission.UPDATE_DEVICE_STATS" />
+    <uses-permission android:name="android.permission.WRITE_SETTINGS" />
+
+    <protected-broadcast android:name="com.android.server.connectivity.tethering.DISABLE_TETHERING" />
+
+    <application
+        android:process="com.android.networkstack.process"
+        android:extractNativeLibs="false"
+        android:persistent="true">
+        <service android:name="com.android.networkstack.tethering.TetheringService"
+                 android:permission="android.permission.MAINLINE_NETWORK_STACK"
+                 android:exported="true">
+            <intent-filter>
+                <action android:name="android.net.ITetheringConnector"/>
+            </intent-filter>
+        </service>
+    </application>
+</manifest>
diff --git a/Tethering/AndroidManifestBase.xml b/Tethering/AndroidManifestBase.xml
new file mode 100644
index 0000000..97c39888
--- /dev/null
+++ b/Tethering/AndroidManifestBase.xml
@@ -0,0 +1,29 @@
+<?xml version="1.0" encoding="utf-8"?>
+<!--
+/*
+ * Copyright (C) 2019 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+-->
+<manifest xmlns:android="http://schemas.android.com/apk/res/android"
+          package="com.android.networkstack.tethering"
+          android:versionCode="1"
+          android:versionName="R-initial">
+    <application
+        android:label="Tethering"
+        android:defaultToDeviceProtectedStorage="true"
+        android:directBootAware="true"
+        android:usesCleartextTraffic="true">
+    </application>
+</manifest>
diff --git a/Tethering/AndroidManifest_InProcess.xml b/Tethering/AndroidManifest_InProcess.xml
new file mode 100644
index 0000000..b1f1240
--- /dev/null
+++ b/Tethering/AndroidManifest_InProcess.xml
@@ -0,0 +1,34 @@
+<?xml version="1.0" encoding="utf-8"?>
+<!--
+/*
+ * Copyright (C) 2019 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+-->
+<manifest xmlns:android="http://schemas.android.com/apk/res/android"
+          package="com.android.networkstack.tethering.inprocess"
+          android:sharedUserId="android.uid.system"
+          android:process="system">
+    <uses-sdk android:minSdkVersion="29" android:targetSdkVersion="29" />
+    <application>
+        <service android:name="com.android.networkstack.tethering.TetheringService"
+                 android:process="system"
+                 android:permission="android.permission.MAINLINE_NETWORK_STACK"
+                 android:exported="true">
+            <intent-filter>
+                <action android:name="android.net.ITetheringConnector.InProcess"/>
+            </intent-filter>
+        </service>
+    </application>
+</manifest>
diff --git a/Tethering/OWNERS b/Tethering/OWNERS
new file mode 100644
index 0000000..5b42d49
--- /dev/null
+++ b/Tethering/OWNERS
@@ -0,0 +1,2 @@
+include platform/packages/modules/NetworkStack/:/OWNERS
+markchien@google.com
diff --git a/Tethering/TEST_MAPPING b/Tethering/TEST_MAPPING
new file mode 100644
index 0000000..5617b0c
--- /dev/null
+++ b/Tethering/TEST_MAPPING
@@ -0,0 +1,12 @@
+{
+  "presubmit": [
+    {
+      "name": "TetheringTests"
+    }
+  ],
+  "postsubmit": [
+    {
+      "name": "TetheringIntegrationTests"
+    }
+  ]
+}
diff --git a/Tethering/apex/Android.bp b/Tethering/apex/Android.bp
new file mode 100644
index 0000000..0524374
--- /dev/null
+++ b/Tethering/apex/Android.bp
@@ -0,0 +1,48 @@
+//
+// Copyright (C) 2019 The Android Open Source Project
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//      http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+//
+
+apex {
+    name: "com.android.tethering",
+    updatable: true,
+    min_sdk_version: "current",
+    java_libs: ["framework-tethering"],
+    bpfs: ["offload.o"],
+    apps: ["Tethering"],
+    manifest: "manifest.json",
+    key: "com.android.tethering.key",
+
+    androidManifest: "AndroidManifest.xml",
+}
+
+apex_key {
+    name: "com.android.tethering.key",
+    public_key: "com.android.tethering.avbpubkey",
+    private_key: "com.android.tethering.pem",
+}
+
+android_app_certificate {
+    name: "com.android.tethering.certificate",
+    certificate: "com.android.tethering",
+}
+
+override_apex {
+    name: "com.android.tethering.inprocess",
+    base: "com.android.tethering",
+    package_name: "com.android.tethering.inprocess",
+    apps: [
+        "InProcessTethering",
+    ],
+}
diff --git a/Tethering/apex/AndroidManifest.xml b/Tethering/apex/AndroidManifest.xml
new file mode 100644
index 0000000..4aae3cc
--- /dev/null
+++ b/Tethering/apex/AndroidManifest.xml
@@ -0,0 +1,29 @@
+<?xml version="1.0" encoding="utf-8"?>
+<!--
+ * Copyright (C) 2019 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ -->
+<manifest xmlns:android="http://schemas.android.com/apk/res/android"
+  package="com.android.tethering">
+  <!-- APEX does not have classes.dex -->
+  <application android:hasCode="false" />
+  <!-- b/145383354: Current minSdk is locked to Q for development cycle, lock it to next version
+                    before ship. -->
+  <!-- TODO: Uncomment this when the R API level is fixed. b/148281152 -->
+  <!--uses-sdk
+      android:minSdkVersion="29"
+      android:targetSdkVersion="29"
+  />
+  -->
+</manifest>
diff --git a/Tethering/apex/com.android.tethering.avbpubkey b/Tethering/apex/com.android.tethering.avbpubkey
new file mode 100644
index 0000000..9a2c017
--- /dev/null
+++ b/Tethering/apex/com.android.tethering.avbpubkey
Binary files differ
diff --git a/Tethering/apex/com.android.tethering.pem b/Tethering/apex/com.android.tethering.pem
new file mode 100644
index 0000000..d4f39ab
--- /dev/null
+++ b/Tethering/apex/com.android.tethering.pem
@@ -0,0 +1,51 @@
+-----BEGIN RSA PRIVATE KEY-----
+MIIJKgIBAAKCAgEA+AWTp03PBRMGt4mVNLt5PDoFFSfmFOVTM7jt5AJXnQMIDsAM
+1cyWGWRridGIpoHAaCALVgW5aRySgi8yV5xP4w0YHcKbfh9M6I9oz4RUo4GQBZfX
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+EiKpodN0YeEn6Ghzplan8rUha+7TP7AYnS5pCszsCHKd03Py0lMLkF+uAfVsDA==
+-----END RSA PRIVATE KEY-----
diff --git a/Tethering/apex/com.android.tethering.pk8 b/Tethering/apex/com.android.tethering.pk8
new file mode 100644
index 0000000..3b94405
--- /dev/null
+++ b/Tethering/apex/com.android.tethering.pk8
Binary files differ
diff --git a/Tethering/apex/com.android.tethering.x509.pem b/Tethering/apex/com.android.tethering.x509.pem
new file mode 100644
index 0000000..a1786e3
--- /dev/null
+++ b/Tethering/apex/com.android.tethering.x509.pem
@@ -0,0 +1,35 @@
+-----BEGIN CERTIFICATE-----
+MIIGKTCCBBGgAwIBAgIUNiSs5EMqxCZ31gWWCcRJVp9HffAwDQYJKoZIhvcNAQEL
+BQAwgaIxCzAJBgNVBAYTAlVTMRMwEQYDVQQIDApDYWxpZm9ybmlhMRYwFAYDVQQH
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++oGwD2ZNzZRaPOoWxjwohBWQ6mySuvF9RRRb300qmxxUGFM9Ki3aqrWlYlHEOwOC
+M+gIXxYFO7S+yUzf6/gMZLOz2YqfcTOup4hAxtExR7niutxJSsRLPBL237exAJoz
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++qi6ulElZvSwx0qm+S0QiPyGFlxrsdnHoGJl1tzjJW8KdNZRvzRLUQtbphPp+VkL
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+QNs3k4JTRecamMzqIkylhlnEC4FjWc6Bx4wsEpwBMZOkF/tGGMZYf2C09a8tpP0C
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+MBaAFNP5gIpNWmq0xa411M1GaRPbEijvMA8GA1UdEwEB/wQFMAMBAf8wDQYJKoZI
+hvcNAQELBQADggIBADJGmU3QP4EGbt6eBhVPeo/efsqrHsuB2fvFzvIobJbfkSob
+cmvjbzIikOlPAgFWj8lT5SDcIWRorFf1u2JylClJ0nSDcqJMHVKmT7wseV/KtX//
+1yUyJFRQVzmjC89dp8OIc00GmItivKLer3NbJdkR3rTUjg7+bNUO27Qp3AFREmiJ
+P+M7ouvcQRvByUWbp/LOrJpMdJLysRBO562RwrtwTjltdvufyYswbBZOKEiUh1Jc
+Ged+3+SJdhwq3Wy+R3Uj7YE7mUMu1QNbANIMrwF8W93EA53eoL2+cKmuaVU6ZURL
+xgSJaY6TrunnSI9XTROLtjsFlJorYWy2tvG7Q5Hw3OkO2Xdz/mm85VTkiusg9DMB
+WWTv607YtsIO0FhKmcV4bp3q/EkRj3t/zLvL9uFJrWDGkuShZq6fQvqbCvaokOPY
++M0ZRIwgwa9UpEE0BMklVWqR6BGyap614gOgcOjYM70WRNl59Qne+g128ZN7g9nz
+61F70i7kUngV0ZUz1/Fu/NCG+6wGF85ZbFmQl60YHPDw1FtjVUuKyBblaDzdJunx
+yQr2t9RUokzFBFK0lGW3+yf0WDQ5fqTMs5h8bz1FCq8/HzWmpdOfqePLe4zsld3b
+1nFuSohaIfbn/HDdTNtTBGQPgz8ZswQ6ejJJqTLz9D/odbqn9LeIhDZXcQTf
+-----END CERTIFICATE-----
diff --git a/Tethering/apex/manifest.json b/Tethering/apex/manifest.json
new file mode 100644
index 0000000..8836c4e
--- /dev/null
+++ b/Tethering/apex/manifest.json
@@ -0,0 +1,4 @@
+{
+  "name": "com.android.tethering",
+  "version": 300900700
+}
diff --git a/Tethering/bpf_progs/Android.bp b/Tethering/bpf_progs/Android.bp
new file mode 100644
index 0000000..d54f861
--- /dev/null
+++ b/Tethering/bpf_progs/Android.bp
@@ -0,0 +1,33 @@
+//
+// Copyright (C) 2020 The Android Open Source Project
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//      http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+//
+
+//
+// bpf kernel programs
+//
+bpf {
+    name: "offload.o",
+    srcs: ["offload.c"],
+    cflags: [
+        "-Wall",
+        "-Werror",
+    ],
+    include_dirs: [
+        // TODO: get rid of system/netd.
+        "system/netd/bpf_progs",             // for bpf_net_helpers.h
+        "system/netd/libnetdbpf/include",    // for bpf_shared.h
+        "system/netd/libnetdutils/include",  // for UidConstants.h
+    ],
+}
diff --git a/Tethering/bpf_progs/offload.c b/Tethering/bpf_progs/offload.c
new file mode 100644
index 0000000..cc5af31
--- /dev/null
+++ b/Tethering/bpf_progs/offload.c
@@ -0,0 +1,207 @@
+/*
+ * Copyright (C) 2020 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include <linux/if.h>
+#include <linux/ip.h>
+#include <linux/ipv6.h>
+#include <linux/pkt_cls.h>
+#include <linux/tcp.h>
+
+#include "bpf_helpers.h"
+#include "bpf_net_helpers.h"
+#include "netdbpf/bpf_shared.h"
+
+DEFINE_BPF_MAP_GRW(tether_ingress_map, HASH, TetherIngressKey, TetherIngressValue, 64,
+                   AID_NETWORK_STACK)
+
+// Tethering stats, indexed by upstream interface.
+DEFINE_BPF_MAP_GRW(tether_stats_map, HASH, uint32_t, TetherStatsValue, 16, AID_NETWORK_STACK)
+
+// Tethering data limit, indexed by upstream interface.
+// (tethering allowed when stats[iif].rxBytes + stats[iif].txBytes < limit[iif])
+DEFINE_BPF_MAP_GRW(tether_limit_map, HASH, uint32_t, uint64_t, 16, AID_NETWORK_STACK)
+
+static inline __always_inline int do_forward(struct __sk_buff* skb, bool is_ethernet) {
+    int l2_header_size = is_ethernet ? sizeof(struct ethhdr) : 0;
+    void* data = (void*)(long)skb->data;
+    const void* data_end = (void*)(long)skb->data_end;
+    struct ethhdr* eth = is_ethernet ? data : NULL;  // used iff is_ethernet
+    struct ipv6hdr* ip6 = is_ethernet ? (void*)(eth + 1) : data;
+
+    // Must be meta-ethernet IPv6 frame
+    if (skb->protocol != htons(ETH_P_IPV6)) return TC_ACT_OK;
+
+    // Must have (ethernet and) ipv6 header
+    if (data + l2_header_size + sizeof(*ip6) > data_end) return TC_ACT_OK;
+
+    // Ethertype - if present - must be IPv6
+    if (is_ethernet && (eth->h_proto != htons(ETH_P_IPV6))) return TC_ACT_OK;
+
+    // IP version must be 6
+    if (ip6->version != 6) return TC_ACT_OK;
+
+    // Cannot decrement during forward if already zero or would be zero,
+    // Let the kernel's stack handle these cases and generate appropriate ICMP errors.
+    if (ip6->hop_limit <= 1) return TC_ACT_OK;
+
+    // Protect against forwarding packets sourced from ::1 or fe80::/64 or other weirdness.
+    __be32 src32 = ip6->saddr.s6_addr32[0];
+    if (src32 != htonl(0x0064ff9b) &&                        // 64:ff9b:/32 incl. XLAT464 WKP
+        (src32 & htonl(0xe0000000)) != htonl(0x20000000))    // 2000::/3 Global Unicast
+        return TC_ACT_OK;
+
+    TetherIngressKey k = {
+            .iif = skb->ifindex,
+            .neigh6 = ip6->daddr,
+    };
+
+    TetherIngressValue* v = bpf_tether_ingress_map_lookup_elem(&k);
+
+    // If we don't find any offload information then simply let the core stack handle it...
+    if (!v) return TC_ACT_OK;
+
+    uint32_t stat_and_limit_k = skb->ifindex;
+
+    TetherStatsValue* stat_v = bpf_tether_stats_map_lookup_elem(&stat_and_limit_k);
+
+    // If we don't have anywhere to put stats, then abort...
+    if (!stat_v) return TC_ACT_OK;
+
+    uint64_t* limit_v = bpf_tether_limit_map_lookup_elem(&stat_and_limit_k);
+
+    // If we don't have a limit, then abort...
+    if (!limit_v) return TC_ACT_OK;
+
+    // Required IPv6 minimum mtu is 1280, below that not clear what we should do, abort...
+    const int pmtu = v->pmtu;
+    if (pmtu < IPV6_MIN_MTU) return TC_ACT_OK;
+
+    // Approximate handling of TCP/IPv6 overhead for incoming LRO/GRO packets: default
+    // outbound path mtu of 1500 is not necessarily correct, but worst case we simply
+    // undercount, which is still better then not accounting for this overhead at all.
+    // Note: this really shouldn't be device/path mtu at all, but rather should be
+    // derived from this particular connection's mss (ie. from gro segment size).
+    // This would require a much newer kernel with newer ebpf accessors.
+    // (This is also blindly assuming 12 bytes of tcp timestamp option in tcp header)
+    uint64_t packets = 1;
+    uint64_t bytes = skb->len;
+    if (bytes > pmtu) {
+        const int tcp_overhead = sizeof(struct ipv6hdr) + sizeof(struct tcphdr) + 12;
+        const int mss = pmtu - tcp_overhead;
+        const uint64_t payload = bytes - tcp_overhead;
+        packets = (payload + mss - 1) / mss;
+        bytes = tcp_overhead * packets + payload;
+    }
+
+    // Are we past the limit?  If so, then abort...
+    // Note: will not overflow since u64 is 936 years even at 5Gbps.
+    // Do not drop here.  Offload is just that, whenever we fail to handle
+    // a packet we let the core stack deal with things.
+    // (The core stack needs to handle limits correctly anyway,
+    // since we don't offload all traffic in both directions)
+    if (stat_v->rxBytes + stat_v->txBytes + bytes > *limit_v) return TC_ACT_OK;
+
+    if (!is_ethernet) {
+        is_ethernet = true;
+        l2_header_size = sizeof(struct ethhdr);
+        // Try to inject an ethernet header, and simply return if we fail
+        if (bpf_skb_change_head(skb, l2_header_size, /*flags*/ 0)) {
+            __sync_fetch_and_add(&stat_v->rxErrors, 1);
+            return TC_ACT_OK;
+        }
+
+        // bpf_skb_change_head() invalidates all pointers - reload them
+        data = (void*)(long)skb->data;
+        data_end = (void*)(long)skb->data_end;
+        eth = data;
+        ip6 = (void*)(eth + 1);
+
+        // I do not believe this can ever happen, but keep the verifier happy...
+        if (data + l2_header_size + sizeof(*ip6) > data_end) {
+            __sync_fetch_and_add(&stat_v->rxErrors, 1);
+            return TC_ACT_SHOT;
+        }
+    };
+
+    // CHECKSUM_COMPLETE is a 16-bit one's complement sum,
+    // thus corrections for it need to be done in 16-byte chunks at even offsets.
+    // IPv6 nexthdr is at offset 6, while hop limit is at offset 7
+    uint8_t old_hl = ip6->hop_limit;
+    --ip6->hop_limit;
+    uint8_t new_hl = ip6->hop_limit;
+
+    // bpf_csum_update() always succeeds if the skb is CHECKSUM_COMPLETE and returns an error
+    // (-ENOTSUPP) if it isn't.
+    bpf_csum_update(skb, 0xFFFF - ntohs(old_hl) + ntohs(new_hl));
+
+    __sync_fetch_and_add(&stat_v->rxPackets, packets);
+    __sync_fetch_and_add(&stat_v->rxBytes, bytes);
+
+    // Overwrite any mac header with the new one
+    *eth = v->macHeader;
+
+    // Redirect to forwarded interface.
+    //
+    // Note that bpf_redirect() cannot fail unless you pass invalid flags.
+    // The redirect actually happens after the ebpf program has already terminated,
+    // and can fail for example for mtu reasons at that point in time, but there's nothing
+    // we can do about it here.
+    return bpf_redirect(v->oif, 0 /* this is effectively BPF_F_EGRESS */);
+}
+
+SEC("schedcls/ingress/tether_ether")
+int sched_cls_ingress_tether_ether(struct __sk_buff* skb) {
+    return do_forward(skb, true);
+}
+
+// Note: section names must be unique to prevent programs from appending to each other,
+// so instead the bpf loader will strip everything past the final $ symbol when actually
+// pinning the program into the filesystem.
+//
+// bpf_skb_change_head() is only present on 4.14+ and 2 trivial kernel patches are needed:
+//   ANDROID: net: bpf: Allow TC programs to call BPF_FUNC_skb_change_head
+//   ANDROID: net: bpf: permit redirect from ingress L3 to egress L2 devices at near max mtu
+// (the first of those has already been upstreamed)
+//
+// 5.4 kernel support was only added to Android Common Kernel in R,
+// and thus a 5.4 kernel always supports this.
+//
+// Hence, this mandatory (must load successfully) implementation for 5.4+ kernels:
+DEFINE_BPF_PROG_KVER("schedcls/ingress/tether_rawip$5_4", AID_ROOT, AID_ROOT,
+                     sched_cls_ingress_tether_rawip_5_4, KVER(5, 4, 0))
+(struct __sk_buff* skb) {
+    return do_forward(skb, false);
+}
+
+// and this identical optional (may fail to load) implementation for [4.14..5.4) patched kernels:
+DEFINE_OPTIONAL_BPF_PROG_KVER_RANGE("schedcls/ingress/tether_rawip$4_14", AID_ROOT, AID_ROOT,
+                                    sched_cls_ingress_tether_rawip_4_14, KVER(4, 14, 0),
+                                    KVER(5, 4, 0))
+(struct __sk_buff* skb) {
+    return do_forward(skb, false);
+}
+
+// and define a no-op stub for [4.9,4.14) and unpatched [4.14,5.4) kernels.
+// (if the above real 4.14+ program loaded successfully, then bpfloader will have already pinned
+// it at the same location this one would be pinned at and will thus skip loading this stub)
+DEFINE_BPF_PROG_KVER_RANGE("schedcls/ingress/tether_rawip$stub", AID_ROOT, AID_ROOT,
+                           sched_cls_ingress_tether_rawip_stub, KVER_NONE, KVER(5, 4, 0))
+(struct __sk_buff* skb) {
+    return TC_ACT_OK;
+}
+
+LICENSE("Apache 2.0");
+CRITICAL("netd");
diff --git a/Tethering/common/TetheringLib/Android.bp b/Tethering/common/TetheringLib/Android.bp
new file mode 100644
index 0000000..ddb6880
--- /dev/null
+++ b/Tethering/common/TetheringLib/Android.bp
@@ -0,0 +1,50 @@
+//
+// Copyright (C) 2019 The Android Open Source Project
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//      http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+java_sdk_library {
+    name: "framework-tethering",
+    defaults: ["framework-module-defaults"],
+    impl_library_visibility: [
+        "//frameworks/base/packages/Tethering:__subpackages__",
+        "//packages/modules/Connectivity/Tethering:__subpackages__",
+    ],
+
+    srcs: [":framework-tethering-srcs"],
+
+    jarjar_rules: "jarjar-rules.txt",
+    installable: true,
+
+    hostdex: true, // for hiddenapi check
+    apex_available: ["com.android.tethering"],
+    permitted_packages: ["android.net"],
+}
+
+filegroup {
+    name: "framework-tethering-srcs",
+    srcs: [
+        "src/android/net/TetheredClient.aidl",
+        "src/android/net/TetheredClient.java",
+        "src/android/net/TetheringManager.java",
+        "src/android/net/TetheringConstants.java",
+        "src/android/net/IIntResultListener.aidl",
+        "src/android/net/ITetheringEventCallback.aidl",
+        "src/android/net/ITetheringConnector.aidl",
+        "src/android/net/TetheringCallbackStartedParcel.aidl",
+        "src/android/net/TetheringConfigurationParcel.aidl",
+        "src/android/net/TetheringRequestParcel.aidl",
+        "src/android/net/TetherStatesParcel.aidl",
+    ],
+    path: "src"
+}
diff --git a/Tethering/common/TetheringLib/api/current.txt b/Tethering/common/TetheringLib/api/current.txt
new file mode 100644
index 0000000..d802177
--- /dev/null
+++ b/Tethering/common/TetheringLib/api/current.txt
@@ -0,0 +1 @@
+// Signature format: 2.0
diff --git a/Tethering/common/TetheringLib/api/module-lib-current.txt b/Tethering/common/TetheringLib/api/module-lib-current.txt
new file mode 100644
index 0000000..6ddb122
--- /dev/null
+++ b/Tethering/common/TetheringLib/api/module-lib-current.txt
@@ -0,0 +1,41 @@
+// Signature format: 2.0
+package android.net {
+
+  public final class TetheringConstants {
+    field public static final String EXTRA_ADD_TETHER_TYPE = "extraAddTetherType";
+    field public static final String EXTRA_PROVISION_CALLBACK = "extraProvisionCallback";
+    field public static final String EXTRA_REM_TETHER_TYPE = "extraRemTetherType";
+    field public static final String EXTRA_RUN_PROVISION = "extraRunProvision";
+    field public static final String EXTRA_SET_ALARM = "extraSetAlarm";
+  }
+
+  public class TetheringManager {
+    ctor public TetheringManager(@NonNull android.content.Context, @NonNull java.util.function.Supplier<android.os.IBinder>);
+    method public int getLastTetherError(@NonNull String);
+    method @NonNull public String[] getTetherableBluetoothRegexs();
+    method @NonNull public String[] getTetherableIfaces();
+    method @NonNull public String[] getTetherableUsbRegexs();
+    method @NonNull public String[] getTetherableWifiRegexs();
+    method @NonNull public String[] getTetheredIfaces();
+    method @NonNull public String[] getTetheringErroredIfaces();
+    method public boolean isTetheringSupported();
+    method public boolean isTetheringSupported(@NonNull String);
+    method public void requestLatestTetheringEntitlementResult(int, @NonNull android.os.ResultReceiver, boolean);
+    method @Deprecated public int setUsbTethering(boolean);
+    method @RequiresPermission(anyOf={android.Manifest.permission.TETHER_PRIVILEGED, android.Manifest.permission.WRITE_SETTINGS}) public void startTethering(int, @NonNull java.util.concurrent.Executor, @NonNull android.net.TetheringManager.StartTetheringCallback);
+    method @Deprecated public int tether(@NonNull String);
+    method @Deprecated public int untether(@NonNull String);
+  }
+
+  public static interface TetheringManager.TetheringEventCallback {
+    method public default void onTetherableInterfaceRegexpsChanged(@NonNull android.net.TetheringManager.TetheringInterfaceRegexps);
+  }
+
+  public static class TetheringManager.TetheringInterfaceRegexps {
+    method @NonNull public java.util.List<java.lang.String> getTetherableBluetoothRegexs();
+    method @NonNull public java.util.List<java.lang.String> getTetherableUsbRegexs();
+    method @NonNull public java.util.List<java.lang.String> getTetherableWifiRegexs();
+  }
+
+}
+
diff --git a/Tethering/common/TetheringLib/api/module-lib-removed.txt b/Tethering/common/TetheringLib/api/module-lib-removed.txt
new file mode 100644
index 0000000..d802177
--- /dev/null
+++ b/Tethering/common/TetheringLib/api/module-lib-removed.txt
@@ -0,0 +1 @@
+// Signature format: 2.0
diff --git a/Tethering/common/TetheringLib/api/removed.txt b/Tethering/common/TetheringLib/api/removed.txt
new file mode 100644
index 0000000..d802177
--- /dev/null
+++ b/Tethering/common/TetheringLib/api/removed.txt
@@ -0,0 +1 @@
+// Signature format: 2.0
diff --git a/Tethering/common/TetheringLib/api/system-current.txt b/Tethering/common/TetheringLib/api/system-current.txt
new file mode 100644
index 0000000..edd1ebb
--- /dev/null
+++ b/Tethering/common/TetheringLib/api/system-current.txt
@@ -0,0 +1,99 @@
+// Signature format: 2.0
+package android.net {
+
+  public final class TetheredClient implements android.os.Parcelable {
+    ctor public TetheredClient(@NonNull android.net.MacAddress, @NonNull java.util.Collection<android.net.TetheredClient.AddressInfo>, int);
+    method public int describeContents();
+    method @NonNull public java.util.List<android.net.TetheredClient.AddressInfo> getAddresses();
+    method @NonNull public android.net.MacAddress getMacAddress();
+    method public int getTetheringType();
+    method public void writeToParcel(@NonNull android.os.Parcel, int);
+    field @NonNull public static final android.os.Parcelable.Creator<android.net.TetheredClient> CREATOR;
+  }
+
+  public static final class TetheredClient.AddressInfo implements android.os.Parcelable {
+    method public int describeContents();
+    method @NonNull public android.net.LinkAddress getAddress();
+    method @Nullable public String getHostname();
+    method public void writeToParcel(@NonNull android.os.Parcel, int);
+    field @NonNull public static final android.os.Parcelable.Creator<android.net.TetheredClient.AddressInfo> CREATOR;
+  }
+
+  public class TetheringManager {
+    method @RequiresPermission(android.Manifest.permission.ACCESS_NETWORK_STATE) public void registerTetheringEventCallback(@NonNull java.util.concurrent.Executor, @NonNull android.net.TetheringManager.TetheringEventCallback);
+    method @RequiresPermission(anyOf={android.Manifest.permission.TETHER_PRIVILEGED, android.Manifest.permission.WRITE_SETTINGS}) public void requestLatestTetheringEntitlementResult(int, boolean, @NonNull java.util.concurrent.Executor, @NonNull android.net.TetheringManager.OnTetheringEntitlementResultListener);
+    method @RequiresPermission(anyOf={android.Manifest.permission.TETHER_PRIVILEGED, android.Manifest.permission.WRITE_SETTINGS}) public void startTethering(@NonNull android.net.TetheringManager.TetheringRequest, @NonNull java.util.concurrent.Executor, @NonNull android.net.TetheringManager.StartTetheringCallback);
+    method @RequiresPermission(anyOf={android.Manifest.permission.TETHER_PRIVILEGED, android.Manifest.permission.WRITE_SETTINGS}) public void stopAllTethering();
+    method @RequiresPermission(anyOf={android.Manifest.permission.TETHER_PRIVILEGED, android.Manifest.permission.WRITE_SETTINGS}) public void stopTethering(int);
+    method @RequiresPermission(anyOf={android.Manifest.permission.TETHER_PRIVILEGED, android.Manifest.permission.ACCESS_NETWORK_STATE}) public void unregisterTetheringEventCallback(@NonNull android.net.TetheringManager.TetheringEventCallback);
+    field public static final String ACTION_TETHER_STATE_CHANGED = "android.net.conn.TETHER_STATE_CHANGED";
+    field public static final String EXTRA_ACTIVE_LOCAL_ONLY = "android.net.extra.ACTIVE_LOCAL_ONLY";
+    field public static final String EXTRA_ACTIVE_TETHER = "tetherArray";
+    field public static final String EXTRA_AVAILABLE_TETHER = "availableArray";
+    field public static final String EXTRA_ERRORED_TETHER = "erroredArray";
+    field public static final int TETHERING_BLUETOOTH = 2; // 0x2
+    field public static final int TETHERING_ETHERNET = 5; // 0x5
+    field public static final int TETHERING_INVALID = -1; // 0xffffffff
+    field public static final int TETHERING_NCM = 4; // 0x4
+    field public static final int TETHERING_USB = 1; // 0x1
+    field public static final int TETHERING_WIFI = 0; // 0x0
+    field public static final int TETHERING_WIFI_P2P = 3; // 0x3
+    field public static final int TETHER_ERROR_DHCPSERVER_ERROR = 12; // 0xc
+    field public static final int TETHER_ERROR_DISABLE_FORWARDING_ERROR = 9; // 0x9
+    field public static final int TETHER_ERROR_ENABLE_FORWARDING_ERROR = 8; // 0x8
+    field public static final int TETHER_ERROR_ENTITLEMENT_UNKNOWN = 13; // 0xd
+    field public static final int TETHER_ERROR_IFACE_CFG_ERROR = 10; // 0xa
+    field public static final int TETHER_ERROR_INTERNAL_ERROR = 5; // 0x5
+    field public static final int TETHER_ERROR_NO_ACCESS_TETHERING_PERMISSION = 15; // 0xf
+    field public static final int TETHER_ERROR_NO_CHANGE_TETHERING_PERMISSION = 14; // 0xe
+    field public static final int TETHER_ERROR_NO_ERROR = 0; // 0x0
+    field public static final int TETHER_ERROR_PROVISIONING_FAILED = 11; // 0xb
+    field public static final int TETHER_ERROR_SERVICE_UNAVAIL = 2; // 0x2
+    field public static final int TETHER_ERROR_TETHER_IFACE_ERROR = 6; // 0x6
+    field public static final int TETHER_ERROR_UNAVAIL_IFACE = 4; // 0x4
+    field public static final int TETHER_ERROR_UNKNOWN_IFACE = 1; // 0x1
+    field public static final int TETHER_ERROR_UNKNOWN_TYPE = 16; // 0x10
+    field public static final int TETHER_ERROR_UNSUPPORTED = 3; // 0x3
+    field public static final int TETHER_ERROR_UNTETHER_IFACE_ERROR = 7; // 0x7
+    field public static final int TETHER_HARDWARE_OFFLOAD_FAILED = 2; // 0x2
+    field public static final int TETHER_HARDWARE_OFFLOAD_STARTED = 1; // 0x1
+    field public static final int TETHER_HARDWARE_OFFLOAD_STOPPED = 0; // 0x0
+  }
+
+  public static interface TetheringManager.OnTetheringEntitlementResultListener {
+    method public void onTetheringEntitlementResult(int);
+  }
+
+  public static interface TetheringManager.StartTetheringCallback {
+    method public default void onTetheringFailed(int);
+    method public default void onTetheringStarted();
+  }
+
+  public static interface TetheringManager.TetheringEventCallback {
+    method public default void onClientsChanged(@NonNull java.util.Collection<android.net.TetheredClient>);
+    method public default void onError(@NonNull String, int);
+    method public default void onOffloadStatusChanged(int);
+    method public default void onTetherableInterfacesChanged(@NonNull java.util.List<java.lang.String>);
+    method public default void onTetheredInterfacesChanged(@NonNull java.util.List<java.lang.String>);
+    method public default void onTetheringSupported(boolean);
+    method public default void onUpstreamChanged(@Nullable android.net.Network);
+  }
+
+  public static class TetheringManager.TetheringRequest {
+    method @Nullable public android.net.LinkAddress getClientStaticIpv4Address();
+    method @Nullable public android.net.LinkAddress getLocalIpv4Address();
+    method public boolean getShouldShowEntitlementUi();
+    method public int getTetheringType();
+    method public boolean isExemptFromEntitlementCheck();
+  }
+
+  public static class TetheringManager.TetheringRequest.Builder {
+    ctor public TetheringManager.TetheringRequest.Builder(int);
+    method @NonNull public android.net.TetheringManager.TetheringRequest build();
+    method @NonNull @RequiresPermission(android.Manifest.permission.TETHER_PRIVILEGED) public android.net.TetheringManager.TetheringRequest.Builder setExemptFromEntitlementCheck(boolean);
+    method @NonNull @RequiresPermission(android.Manifest.permission.TETHER_PRIVILEGED) public android.net.TetheringManager.TetheringRequest.Builder setShouldShowEntitlementUi(boolean);
+    method @NonNull @RequiresPermission(android.Manifest.permission.TETHER_PRIVILEGED) public android.net.TetheringManager.TetheringRequest.Builder setStaticIpv4Addresses(@NonNull android.net.LinkAddress, @NonNull android.net.LinkAddress);
+  }
+
+}
+
diff --git a/Tethering/common/TetheringLib/api/system-removed.txt b/Tethering/common/TetheringLib/api/system-removed.txt
new file mode 100644
index 0000000..d802177
--- /dev/null
+++ b/Tethering/common/TetheringLib/api/system-removed.txt
@@ -0,0 +1 @@
+// Signature format: 2.0
diff --git a/Tethering/common/TetheringLib/jarjar-rules.txt b/Tethering/common/TetheringLib/jarjar-rules.txt
new file mode 100644
index 0000000..e459fad
--- /dev/null
+++ b/Tethering/common/TetheringLib/jarjar-rules.txt
@@ -0,0 +1 @@
+# jarjar rules for the bootclasspath tethering framework library here
\ No newline at end of file
diff --git a/Tethering/common/TetheringLib/src/android/net/IIntResultListener.aidl b/Tethering/common/TetheringLib/src/android/net/IIntResultListener.aidl
new file mode 100644
index 0000000..c3d66ee
--- /dev/null
+++ b/Tethering/common/TetheringLib/src/android/net/IIntResultListener.aidl
@@ -0,0 +1,25 @@
+/*
+ * Copyright (C) 2019 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package android.net;
+
+/**
+ * Listener interface allowing objects to listen to various module event.
+ * {@hide}
+ */
+oneway interface IIntResultListener {
+    void onResult(int resultCode);
+}
diff --git a/Tethering/common/TetheringLib/src/android/net/ITetheringConnector.aidl b/Tethering/common/TetheringLib/src/android/net/ITetheringConnector.aidl
new file mode 100644
index 0000000..cf094aa
--- /dev/null
+++ b/Tethering/common/TetheringLib/src/android/net/ITetheringConnector.aidl
@@ -0,0 +1,52 @@
+/*
+ * Copyright (C) 2020 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package android.net;
+
+import android.net.IIntResultListener;
+import android.net.ITetheringEventCallback;
+import android.net.TetheringRequestParcel;
+import android.os.ResultReceiver;
+
+/** @hide */
+oneway interface ITetheringConnector {
+    void tether(String iface, String callerPkg, String callingAttributionTag,
+            IIntResultListener receiver);
+
+    void untether(String iface, String callerPkg, String callingAttributionTag,
+            IIntResultListener receiver);
+
+    void setUsbTethering(boolean enable, String callerPkg,
+            String callingAttributionTag, IIntResultListener receiver);
+
+    void startTethering(in TetheringRequestParcel request, String callerPkg,
+            String callingAttributionTag, IIntResultListener receiver);
+
+    void stopTethering(int type, String callerPkg, String callingAttributionTag,
+            IIntResultListener receiver);
+
+    void requestLatestTetheringEntitlementResult(int type, in ResultReceiver receiver,
+            boolean showEntitlementUi, String callerPkg, String callingAttributionTag);
+
+    void registerTetheringEventCallback(ITetheringEventCallback callback, String callerPkg);
+
+    void unregisterTetheringEventCallback(ITetheringEventCallback callback, String callerPkg);
+
+    void isTetheringSupported(String callerPkg, String callingAttributionTag,
+            IIntResultListener receiver);
+
+    void stopAllTethering(String callerPkg, String callingAttributionTag,
+            IIntResultListener receiver);
+}
diff --git a/Tethering/common/TetheringLib/src/android/net/ITetheringEventCallback.aidl b/Tethering/common/TetheringLib/src/android/net/ITetheringEventCallback.aidl
new file mode 100644
index 0000000..b4e3ba4
--- /dev/null
+++ b/Tethering/common/TetheringLib/src/android/net/ITetheringEventCallback.aidl
@@ -0,0 +1,39 @@
+/*
+ * Copyright (C) 2019 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package android.net;
+
+import android.net.Network;
+import android.net.TetheredClient;
+import android.net.TetheringConfigurationParcel;
+import android.net.TetheringCallbackStartedParcel;
+import android.net.TetherStatesParcel;
+
+/**
+ * Callback class for receiving tethering changed events.
+ * @hide
+ */
+oneway interface ITetheringEventCallback
+{
+    /** Called immediately after the callbacks are registered */
+    void onCallbackStarted(in TetheringCallbackStartedParcel parcel);
+    void onCallbackStopped(int errorCode);
+    void onUpstreamChanged(in Network network);
+    void onConfigurationChanged(in TetheringConfigurationParcel config);
+    void onTetherStatesChanged(in TetherStatesParcel states);
+    void onTetherClientsChanged(in List<TetheredClient> clients);
+    void onOffloadStatusChanged(int status);
+}
diff --git a/Tethering/common/TetheringLib/src/android/net/TetherStatesParcel.aidl b/Tethering/common/TetheringLib/src/android/net/TetherStatesParcel.aidl
new file mode 100644
index 0000000..3d842b3
--- /dev/null
+++ b/Tethering/common/TetheringLib/src/android/net/TetherStatesParcel.aidl
@@ -0,0 +1,31 @@
+/*
+ * Copyright (C) 2019 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package android.net;
+
+/**
+ * Status details for tethering downstream interfaces.
+ * {@hide}
+ */
+parcelable TetherStatesParcel {
+    String[] availableList;
+    String[] tetheredList;
+    String[] localOnlyList;
+    String[] erroredIfaceList;
+    // List of Last error code corresponding to each errored iface in erroredIfaceList. */
+    // TODO: Improve this as b/143122247.
+    int[] lastErrorList;
+}
diff --git a/Tethering/common/TetheringLib/src/android/net/TetheredClient.aidl b/Tethering/common/TetheringLib/src/android/net/TetheredClient.aidl
new file mode 100644
index 0000000..0b279b8
--- /dev/null
+++ b/Tethering/common/TetheringLib/src/android/net/TetheredClient.aidl
@@ -0,0 +1,18 @@
+/**
+ * Copyright (C) 2020 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package android.net;
+
+@JavaOnlyStableParcelable parcelable TetheredClient;
\ No newline at end of file
diff --git a/Tethering/common/TetheringLib/src/android/net/TetheredClient.java b/Tethering/common/TetheringLib/src/android/net/TetheredClient.java
new file mode 100644
index 0000000..0b223f4
--- /dev/null
+++ b/Tethering/common/TetheringLib/src/android/net/TetheredClient.java
@@ -0,0 +1,239 @@
+/*
+ * Copyright (C) 2020 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package android.net;
+
+import android.annotation.NonNull;
+import android.annotation.Nullable;
+import android.annotation.SystemApi;
+import android.os.Parcel;
+import android.os.Parcelable;
+
+import java.util.ArrayList;
+import java.util.Collection;
+import java.util.LinkedHashSet;
+import java.util.List;
+import java.util.Objects;
+
+/**
+ * Information on a tethered downstream client.
+ * @hide
+ */
+@SystemApi
+public final class TetheredClient implements Parcelable {
+    @NonNull
+    private final MacAddress mMacAddress;
+    @NonNull
+    private final List<AddressInfo> mAddresses;
+    // TODO: use an @IntDef here
+    private final int mTetheringType;
+
+    public TetheredClient(@NonNull MacAddress macAddress,
+            @NonNull Collection<AddressInfo> addresses, int tetheringType) {
+        mMacAddress = macAddress;
+        mAddresses = new ArrayList<>(addresses);
+        mTetheringType = tetheringType;
+    }
+
+    private TetheredClient(@NonNull Parcel in) {
+        this(in.readParcelable(null), in.createTypedArrayList(AddressInfo.CREATOR), in.readInt());
+    }
+
+    @Override
+    public void writeToParcel(@NonNull Parcel dest, int flags) {
+        dest.writeParcelable(mMacAddress, flags);
+        dest.writeTypedList(mAddresses);
+        dest.writeInt(mTetheringType);
+    }
+
+    /**
+     * Get the MAC address used to identify the client.
+     */
+    @NonNull
+    public MacAddress getMacAddress() {
+        return mMacAddress;
+    }
+
+    /**
+     * Get information on the list of addresses that are associated with the client.
+     */
+    @NonNull
+    public List<AddressInfo> getAddresses() {
+        return new ArrayList<>(mAddresses);
+    }
+
+    /**
+     * Get the type of tethering used by the client.
+     * @return one of the {@code TetheringManager#TETHERING_*} constants.
+     */
+    public int getTetheringType() {
+        return mTetheringType;
+    }
+
+    /**
+     * Return a new {@link TetheredClient} that has all the attributes of this instance, plus the
+     * {@link AddressInfo} of the provided {@link TetheredClient}.
+     *
+     * <p>Duplicate addresses are removed.
+     * @hide
+     */
+    public TetheredClient addAddresses(@NonNull TetheredClient other) {
+        final LinkedHashSet<AddressInfo> newAddresses = new LinkedHashSet<>(
+                mAddresses.size() + other.mAddresses.size());
+        newAddresses.addAll(mAddresses);
+        newAddresses.addAll(other.mAddresses);
+        return new TetheredClient(mMacAddress, newAddresses, mTetheringType);
+    }
+
+    @Override
+    public int hashCode() {
+        return Objects.hash(mMacAddress, mAddresses, mTetheringType);
+    }
+
+    @Override
+    public boolean equals(@Nullable Object obj) {
+        if (!(obj instanceof TetheredClient)) return false;
+        final TetheredClient other = (TetheredClient) obj;
+        return mMacAddress.equals(other.mMacAddress)
+                && mAddresses.equals(other.mAddresses)
+                && mTetheringType == other.mTetheringType;
+    }
+
+    /**
+     * Information on an lease assigned to a tethered client.
+     */
+    public static final class AddressInfo implements Parcelable {
+        @NonNull
+        private final LinkAddress mAddress;
+        @Nullable
+        private final String mHostname;
+
+        /** @hide */
+        public AddressInfo(@NonNull LinkAddress address, @Nullable String hostname) {
+            this.mAddress = address;
+            this.mHostname = hostname;
+        }
+
+        private AddressInfo(Parcel in) {
+            this(in.readParcelable(null),  in.readString());
+        }
+
+        @Override
+        public void writeToParcel(@NonNull Parcel dest, int flags) {
+            dest.writeParcelable(mAddress, flags);
+            dest.writeString(mHostname);
+        }
+
+        /**
+         * Get the link address (including prefix length and lifetime) used by the client.
+         *
+         * This may be an IPv4 or IPv6 address.
+         */
+        @NonNull
+        public LinkAddress getAddress() {
+            return mAddress;
+        }
+
+        /**
+         * Get the hostname that was advertised by the client when obtaining its address, if any.
+         */
+        @Nullable
+        public String getHostname() {
+            return mHostname;
+        }
+
+        /**
+         * Get the expiration time of the address assigned to the client.
+         * @hide
+         */
+        public long getExpirationTime() {
+            return mAddress.getExpirationTime();
+        }
+
+        @Override
+        public int describeContents() {
+            return 0;
+        }
+
+        @Override
+        public int hashCode() {
+            return Objects.hash(mAddress, mHostname);
+        }
+
+        @Override
+        public boolean equals(@Nullable Object obj) {
+            if (!(obj instanceof AddressInfo)) return false;
+            final AddressInfo other = (AddressInfo) obj;
+            // Use .equals() for addresses as all changes, including address expiry changes,
+            // should be included.
+            return other.mAddress.equals(mAddress)
+                    && Objects.equals(mHostname, other.mHostname);
+        }
+
+        @NonNull
+        public static final Creator<AddressInfo> CREATOR = new Creator<AddressInfo>() {
+            @NonNull
+            @Override
+            public AddressInfo createFromParcel(@NonNull Parcel in) {
+                return new AddressInfo(in);
+            }
+
+            @NonNull
+            @Override
+            public AddressInfo[] newArray(int size) {
+                return new AddressInfo[size];
+            }
+        };
+
+        @NonNull
+        @Override
+        public String toString() {
+            return "AddressInfo {"
+                    + mAddress
+                    + (mHostname != null ? ", hostname " + mHostname : "")
+                    + "}";
+        }
+    }
+
+    @Override
+    public int describeContents() {
+        return 0;
+    }
+
+    @NonNull
+    public static final Creator<TetheredClient> CREATOR = new Creator<TetheredClient>() {
+        @NonNull
+        @Override
+        public TetheredClient createFromParcel(@NonNull Parcel in) {
+            return new TetheredClient(in);
+        }
+
+        @NonNull
+        @Override
+        public TetheredClient[] newArray(int size) {
+            return new TetheredClient[size];
+        }
+    };
+
+    @NonNull
+    @Override
+    public String toString() {
+        return "TetheredClient {hwAddr " + mMacAddress
+                + ", addresses " + mAddresses
+                + ", tetheringType " + mTetheringType
+                + "}";
+    }
+}
diff --git a/Tethering/common/TetheringLib/src/android/net/TetheringCallbackStartedParcel.aidl b/Tethering/common/TetheringLib/src/android/net/TetheringCallbackStartedParcel.aidl
new file mode 100644
index 0000000..253eacb
--- /dev/null
+++ b/Tethering/common/TetheringLib/src/android/net/TetheringCallbackStartedParcel.aidl
@@ -0,0 +1,35 @@
+/*
+ * Copyright (C) 2020 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package android.net;
+
+import android.net.Network;
+import android.net.TetheredClient;
+import android.net.TetheringConfigurationParcel;
+import android.net.TetherStatesParcel;
+
+/**
+ * Initial information reported by tethering upon callback registration.
+ * @hide
+ */
+parcelable TetheringCallbackStartedParcel {
+    boolean tetheringSupported;
+    Network upstreamNetwork;
+    TetheringConfigurationParcel config;
+    TetherStatesParcel states;
+    List<TetheredClient> tetheredClients;
+    int offloadStatus;
+}
diff --git a/Tethering/common/TetheringLib/src/android/net/TetheringConfigurationParcel.aidl b/Tethering/common/TetheringLib/src/android/net/TetheringConfigurationParcel.aidl
new file mode 100644
index 0000000..89f3813
--- /dev/null
+++ b/Tethering/common/TetheringLib/src/android/net/TetheringConfigurationParcel.aidl
@@ -0,0 +1,37 @@
+/*
+ * Copyright (C) 2019 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package android.net;
+
+/**
+ * Configuration details for tethering.
+ * @hide
+ */
+parcelable TetheringConfigurationParcel {
+    int subId;
+    String[] tetherableUsbRegexs;
+    String[] tetherableWifiRegexs;
+    String[] tetherableBluetoothRegexs;
+    boolean isDunRequired;
+    boolean chooseUpstreamAutomatically;
+    int[] preferredUpstreamIfaceTypes;
+    String[] legacyDhcpRanges;
+    String[] defaultIPv4DNS;
+    boolean enableLegacyDhcpServer;
+    String[] provisioningApp;
+    String provisioningAppNoUi;
+    int provisioningCheckPeriod;
+}
diff --git a/Tethering/common/TetheringLib/src/android/net/TetheringConstants.java b/Tethering/common/TetheringLib/src/android/net/TetheringConstants.java
new file mode 100644
index 0000000..f14def6
--- /dev/null
+++ b/Tethering/common/TetheringLib/src/android/net/TetheringConstants.java
@@ -0,0 +1,93 @@
+/*
+ * Copyright (C) 2020 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package android.net;
+
+import static android.annotation.SystemApi.Client.MODULE_LIBRARIES;
+
+import android.annotation.SystemApi;
+import android.os.ResultReceiver;
+
+/**
+ * Collections of constants for internal tethering usage.
+ *
+ * <p>These hidden constants are not in TetheringManager as they are not part of the API stubs
+ * generated for TetheringManager, which prevents the tethering module from linking them at
+ * build time.
+ * TODO: investigate changing the tethering build rules so that Tethering can reference hidden
+ * symbols from framework-tethering even when they are in a non-hidden class.
+ * @hide
+ */
+@SystemApi(client = MODULE_LIBRARIES)
+public final class TetheringConstants {
+    /** An explicit private class to avoid exposing constructor.*/
+    private TetheringConstants() { }
+
+    /**
+     * Extra used for communicating with the TetherService and TetherProvisioningActivity.
+     * Includes the type of tethering to enable if any.
+     */
+    public static final String EXTRA_ADD_TETHER_TYPE = "extraAddTetherType";
+    /**
+     * Extra used for communicating with the TetherService. Includes the type of tethering for
+     * which to cancel provisioning.
+     */
+    public static final String EXTRA_REM_TETHER_TYPE = "extraRemTetherType";
+    /**
+     * Extra used for communicating with the TetherService. True to schedule a recheck of tether
+     * provisioning.
+     */
+    public static final String EXTRA_SET_ALARM = "extraSetAlarm";
+    /**
+     * Tells the TetherService to run a provision check now.
+     */
+    public static final String EXTRA_RUN_PROVISION = "extraRunProvision";
+    /**
+     * Extra used for communicating with the TetherService and TetherProvisioningActivity.
+     * Contains the {@link ResultReceiver} which will receive provisioning results.
+     * Can not be empty.
+     */
+    public static final String EXTRA_PROVISION_CALLBACK = "extraProvisionCallback";
+
+    /**
+     * Extra used for communicating with the TetherService and TetherProvisioningActivity.
+     * Contains the subId of current active cellular upstream.
+     * @hide
+     */
+    public static final String EXTRA_TETHER_SUBID = "android.net.extra.TETHER_SUBID";
+
+    /**
+     * Extra used for telling TetherProvisioningActivity the entitlement package name and class
+     * name to start UI entitlement check.
+     * @hide
+     */
+    public static final String EXTRA_TETHER_UI_PROVISIONING_APP_NAME =
+            "android.net.extra.TETHER_UI_PROVISIONING_APP_NAME";
+
+    /**
+     * Extra used for telling TetherService the intent action to start silent entitlement check.
+     * @hide
+     */
+    public static final String EXTRA_TETHER_SILENT_PROVISIONING_ACTION =
+            "android.net.extra.TETHER_SILENT_PROVISIONING_ACTION";
+
+    /**
+     * Extra used for TetherService to receive the response of provisioning check.
+     * @hide
+     */
+    public static final String EXTRA_TETHER_PROVISIONING_RESPONSE =
+            "android.net.extra.TETHER_PROVISIONING_RESPONSE";
+}
diff --git a/Tethering/common/TetheringLib/src/android/net/TetheringManager.java b/Tethering/common/TetheringLib/src/android/net/TetheringManager.java
new file mode 100644
index 0000000..97fb497
--- /dev/null
+++ b/Tethering/common/TetheringLib/src/android/net/TetheringManager.java
@@ -0,0 +1,1364 @@
+/*
+ * Copyright (C) 2019 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package android.net;
+
+import static android.annotation.SystemApi.Client.MODULE_LIBRARIES;
+
+import android.Manifest;
+import android.annotation.IntDef;
+import android.annotation.NonNull;
+import android.annotation.Nullable;
+import android.annotation.RequiresPermission;
+import android.annotation.SystemApi;
+import android.content.Context;
+import android.os.Bundle;
+import android.os.ConditionVariable;
+import android.os.IBinder;
+import android.os.RemoteException;
+import android.os.ResultReceiver;
+import android.util.ArrayMap;
+import android.util.Log;
+
+import com.android.internal.annotations.GuardedBy;
+
+import java.lang.annotation.Retention;
+import java.lang.annotation.RetentionPolicy;
+import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.Collection;
+import java.util.Collections;
+import java.util.HashMap;
+import java.util.List;
+import java.util.Objects;
+import java.util.concurrent.Executor;
+import java.util.function.Supplier;
+
+/**
+ * This class provides the APIs to control the tethering service.
+ * <p> The primary responsibilities of this class are to provide the APIs for applications to
+ * start tethering, stop tethering, query configuration and query status.
+ *
+ * @hide
+ */
+@SystemApi
+public class TetheringManager {
+    private static final String TAG = TetheringManager.class.getSimpleName();
+    private static final int DEFAULT_TIMEOUT_MS = 60_000;
+    private static final long CONNECTOR_POLL_INTERVAL_MILLIS = 200L;
+
+    @GuardedBy("mConnectorWaitQueue")
+    @Nullable
+    private ITetheringConnector mConnector;
+    @GuardedBy("mConnectorWaitQueue")
+    @NonNull
+    private final List<ConnectorConsumer> mConnectorWaitQueue = new ArrayList<>();
+    private final Supplier<IBinder> mConnectorSupplier;
+
+    private final TetheringCallbackInternal mCallback;
+    private final Context mContext;
+    private final ArrayMap<TetheringEventCallback, ITetheringEventCallback>
+            mTetheringEventCallbacks = new ArrayMap<>();
+
+    private volatile TetheringConfigurationParcel mTetheringConfiguration;
+    private volatile TetherStatesParcel mTetherStatesParcel;
+
+    /**
+     * Broadcast Action: A tetherable connection has come or gone.
+     * Uses {@code TetheringManager.EXTRA_AVAILABLE_TETHER},
+     * {@code TetheringManager.EXTRA_ACTIVE_LOCAL_ONLY},
+     * {@code TetheringManager.EXTRA_ACTIVE_TETHER}, and
+     * {@code TetheringManager.EXTRA_ERRORED_TETHER} to indicate
+     * the current state of tethering.  Each include a list of
+     * interface names in that state (may be empty).
+     */
+    public static final String ACTION_TETHER_STATE_CHANGED =
+            "android.net.conn.TETHER_STATE_CHANGED";
+
+    /**
+     * gives a String[] listing all the interfaces configured for
+     * tethering and currently available for tethering.
+     */
+    public static final String EXTRA_AVAILABLE_TETHER = "availableArray";
+
+    /**
+     * gives a String[] listing all the interfaces currently in local-only
+     * mode (ie, has DHCPv4+IPv6-ULA support and no packet forwarding)
+     */
+    public static final String EXTRA_ACTIVE_LOCAL_ONLY = "android.net.extra.ACTIVE_LOCAL_ONLY";
+
+    /**
+     * gives a String[] listing all the interfaces currently tethered
+     * (ie, has DHCPv4 support and packets potentially forwarded/NATed)
+     */
+    public static final String EXTRA_ACTIVE_TETHER = "tetherArray";
+
+    /**
+     * gives a String[] listing all the interfaces we tried to tether and
+     * failed.  Use {@link #getLastTetherError} to find the error code
+     * for any interfaces listed here.
+     */
+    public static final String EXTRA_ERRORED_TETHER = "erroredArray";
+
+    /** @hide */
+    @Retention(RetentionPolicy.SOURCE)
+    @IntDef(flag = false, value = {
+            TETHERING_WIFI,
+            TETHERING_USB,
+            TETHERING_BLUETOOTH,
+            TETHERING_WIFI_P2P,
+            TETHERING_NCM,
+            TETHERING_ETHERNET,
+    })
+    public @interface TetheringType {
+    }
+
+    /**
+     * Invalid tethering type.
+     * @see #startTethering.
+     */
+    public static final int TETHERING_INVALID   = -1;
+
+    /**
+     * Wifi tethering type.
+     * @see #startTethering.
+     */
+    public static final int TETHERING_WIFI      = 0;
+
+    /**
+     * USB tethering type.
+     * @see #startTethering.
+     */
+    public static final int TETHERING_USB       = 1;
+
+    /**
+     * Bluetooth tethering type.
+     * @see #startTethering.
+     */
+    public static final int TETHERING_BLUETOOTH = 2;
+
+    /**
+     * Wifi P2p tethering type.
+     * Wifi P2p tethering is set through events automatically, and don't
+     * need to start from #startTethering.
+     */
+    public static final int TETHERING_WIFI_P2P = 3;
+
+    /**
+     * Ncm local tethering type.
+     * @see #startTethering(TetheringRequest, Executor, StartTetheringCallback)
+     */
+    public static final int TETHERING_NCM = 4;
+
+    /**
+     * Ethernet tethering type.
+     * @see #startTethering(TetheringRequest, Executor, StartTetheringCallback)
+     */
+    public static final int TETHERING_ETHERNET = 5;
+
+    /**
+     * WIGIG tethering type. Use a separate type to prevent
+     * conflicts with TETHERING_WIFI
+     * This type is only used internally by the tethering module
+     * @hide
+     */
+    public static final int TETHERING_WIGIG = 6;
+
+    /** @hide */
+    @Retention(RetentionPolicy.SOURCE)
+    @IntDef(value = {
+            TETHER_ERROR_NO_ERROR,
+            TETHER_ERROR_PROVISIONING_FAILED,
+            TETHER_ERROR_ENTITLEMENT_UNKNOWN,
+    })
+    public @interface EntitlementResult {
+    }
+
+    /** @hide */
+    @Retention(RetentionPolicy.SOURCE)
+    @IntDef(value = {
+            TETHER_ERROR_NO_ERROR,
+            TETHER_ERROR_UNKNOWN_IFACE,
+            TETHER_ERROR_SERVICE_UNAVAIL,
+            TETHER_ERROR_INTERNAL_ERROR,
+            TETHER_ERROR_TETHER_IFACE_ERROR,
+            TETHER_ERROR_ENABLE_FORWARDING_ERROR,
+            TETHER_ERROR_DISABLE_FORWARDING_ERROR,
+            TETHER_ERROR_IFACE_CFG_ERROR,
+            TETHER_ERROR_DHCPSERVER_ERROR,
+    })
+    public @interface TetheringIfaceError {
+    }
+
+    /** @hide */
+    @Retention(RetentionPolicy.SOURCE)
+    @IntDef(value = {
+            TETHER_ERROR_SERVICE_UNAVAIL,
+            TETHER_ERROR_INTERNAL_ERROR,
+            TETHER_ERROR_NO_CHANGE_TETHERING_PERMISSION,
+            TETHER_ERROR_UNKNOWN_TYPE,
+    })
+    public @interface StartTetheringError {
+    }
+
+    public static final int TETHER_ERROR_NO_ERROR = 0;
+    public static final int TETHER_ERROR_UNKNOWN_IFACE = 1;
+    public static final int TETHER_ERROR_SERVICE_UNAVAIL = 2;
+    public static final int TETHER_ERROR_UNSUPPORTED = 3;
+    public static final int TETHER_ERROR_UNAVAIL_IFACE = 4;
+    public static final int TETHER_ERROR_INTERNAL_ERROR = 5;
+    public static final int TETHER_ERROR_TETHER_IFACE_ERROR = 6;
+    public static final int TETHER_ERROR_UNTETHER_IFACE_ERROR = 7;
+    public static final int TETHER_ERROR_ENABLE_FORWARDING_ERROR = 8;
+    public static final int TETHER_ERROR_DISABLE_FORWARDING_ERROR = 9;
+    public static final int TETHER_ERROR_IFACE_CFG_ERROR = 10;
+    public static final int TETHER_ERROR_PROVISIONING_FAILED = 11;
+    public static final int TETHER_ERROR_DHCPSERVER_ERROR = 12;
+    public static final int TETHER_ERROR_ENTITLEMENT_UNKNOWN = 13;
+    public static final int TETHER_ERROR_NO_CHANGE_TETHERING_PERMISSION = 14;
+    public static final int TETHER_ERROR_NO_ACCESS_TETHERING_PERMISSION = 15;
+    public static final int TETHER_ERROR_UNKNOWN_TYPE = 16;
+
+    /** @hide */
+    @Retention(RetentionPolicy.SOURCE)
+    @IntDef(flag = false, value = {
+            TETHER_HARDWARE_OFFLOAD_STOPPED,
+            TETHER_HARDWARE_OFFLOAD_STARTED,
+            TETHER_HARDWARE_OFFLOAD_FAILED,
+    })
+    public @interface TetherOffloadStatus {
+    }
+
+    /** Tethering offload status is stopped. */
+    public static final int TETHER_HARDWARE_OFFLOAD_STOPPED = 0;
+    /** Tethering offload status is started. */
+    public static final int TETHER_HARDWARE_OFFLOAD_STARTED = 1;
+    /** Fail to start tethering offload. */
+    public static final int TETHER_HARDWARE_OFFLOAD_FAILED = 2;
+
+    /**
+     * Create a TetheringManager object for interacting with the tethering service.
+     *
+     * @param context Context for the manager.
+     * @param connectorSupplier Supplier for the manager connector; may return null while the
+     *                          service is not connected.
+     * {@hide}
+     */
+    @SystemApi(client = MODULE_LIBRARIES)
+    public TetheringManager(@NonNull final Context context,
+            @NonNull Supplier<IBinder> connectorSupplier) {
+        mContext = context;
+        mCallback = new TetheringCallbackInternal();
+        mConnectorSupplier = connectorSupplier;
+
+        final String pkgName = mContext.getOpPackageName();
+
+        final IBinder connector = mConnectorSupplier.get();
+        // If the connector is available on start, do not start a polling thread. This introduces
+        // differences in the thread that sends the oneway binder calls to the service between the
+        // first few seconds after boot and later, but it avoids always having differences between
+        // the first usage of TetheringManager from a process and subsequent usages (so the
+        // difference is only on boot). On boot binder calls may be queued until the service comes
+        // up and be sent from a worker thread; later, they are always sent from the caller thread.
+        // Considering that it's just oneway binder calls, and ordering is preserved, this seems
+        // better than inconsistent behavior persisting after boot.
+        if (connector != null) {
+            mConnector = ITetheringConnector.Stub.asInterface(connector);
+        } else {
+            startPollingForConnector();
+        }
+
+        Log.i(TAG, "registerTetheringEventCallback:" + pkgName);
+        getConnector(c -> c.registerTetheringEventCallback(mCallback, pkgName));
+    }
+
+    private void startPollingForConnector() {
+        new Thread(() -> {
+            while (true) {
+                try {
+                    Thread.sleep(CONNECTOR_POLL_INTERVAL_MILLIS);
+                } catch (InterruptedException e) {
+                    // Not much to do here, the system needs to wait for the connector
+                }
+
+                final IBinder connector = mConnectorSupplier.get();
+                if (connector != null) {
+                    onTetheringConnected(ITetheringConnector.Stub.asInterface(connector));
+                    return;
+                }
+            }
+        }).start();
+    }
+
+    private interface ConnectorConsumer {
+        void onConnectorAvailable(ITetheringConnector connector) throws RemoteException;
+    }
+
+    private void onTetheringConnected(ITetheringConnector connector) {
+        // Process the connector wait queue in order, including any items that are added
+        // while processing.
+        //
+        // 1. Copy the queue to a local variable under lock.
+        // 2. Drain the local queue with the lock released (otherwise, enqueuing future commands
+        //    would block on the lock).
+        // 3. Acquire the lock again. If any new tasks were queued during step 2, goto 1.
+        //    If not, set mConnector to non-null so future tasks are run immediately, not queued.
+        //
+        // For this to work, all calls to the tethering service must use getConnector(), which
+        // ensures that tasks are added to the queue with the lock held.
+        //
+        // Once mConnector is set to non-null, it will never be null again. If the network stack
+        // process crashes, no recovery is possible.
+        // TODO: evaluate whether it is possible to recover from network stack process crashes
+        // (though in most cases the system will have crashed when the network stack process
+        // crashes).
+        do {
+            final List<ConnectorConsumer> localWaitQueue;
+            synchronized (mConnectorWaitQueue) {
+                localWaitQueue = new ArrayList<>(mConnectorWaitQueue);
+                mConnectorWaitQueue.clear();
+            }
+
+            // Allow more tasks to be added at the end without blocking while draining the queue.
+            for (ConnectorConsumer task : localWaitQueue) {
+                try {
+                    task.onConnectorAvailable(connector);
+                } catch (RemoteException e) {
+                    // Most likely the network stack process crashed, which is likely to crash the
+                    // system. Keep processing other requests but report the error loudly.
+                    Log.wtf(TAG, "Error processing request for the tethering connector", e);
+                }
+            }
+
+            synchronized (mConnectorWaitQueue) {
+                if (mConnectorWaitQueue.size() == 0) {
+                    mConnector = connector;
+                    return;
+                }
+            }
+        } while (true);
+    }
+
+    /**
+     * Asynchronously get the ITetheringConnector to execute some operation.
+     *
+     * <p>If the connector is already available, the operation will be executed on the caller's
+     * thread. Otherwise it will be queued and executed on a worker thread. The operation should be
+     * limited to performing oneway binder calls to minimize differences due to threading.
+     */
+    private void getConnector(ConnectorConsumer consumer) {
+        final ITetheringConnector connector;
+        synchronized (mConnectorWaitQueue) {
+            connector = mConnector;
+            if (connector == null) {
+                mConnectorWaitQueue.add(consumer);
+                return;
+            }
+        }
+
+        try {
+            consumer.onConnectorAvailable(connector);
+        } catch (RemoteException e) {
+            throw new IllegalStateException(e);
+        }
+    }
+
+    private interface RequestHelper {
+        void runRequest(ITetheringConnector connector, IIntResultListener listener);
+    }
+
+    // Used to dispatch legacy ConnectivityManager methods that expect tethering to be able to
+    // return results and perform operations synchronously.
+    // TODO: remove once there are no callers of these legacy methods.
+    private class RequestDispatcher {
+        private final ConditionVariable mWaiting;
+        public volatile int mRemoteResult;
+
+        private final IIntResultListener mListener = new IIntResultListener.Stub() {
+                @Override
+                public void onResult(final int resultCode) {
+                    mRemoteResult = resultCode;
+                    mWaiting.open();
+                }
+        };
+
+        RequestDispatcher() {
+            mWaiting = new ConditionVariable();
+        }
+
+        int waitForResult(final RequestHelper request) {
+            getConnector(c -> request.runRequest(c, mListener));
+            if (!mWaiting.block(DEFAULT_TIMEOUT_MS)) {
+                throw new IllegalStateException("Callback timeout");
+            }
+
+            throwIfPermissionFailure(mRemoteResult);
+
+            return mRemoteResult;
+        }
+    }
+
+    private void throwIfPermissionFailure(final int errorCode) {
+        switch (errorCode) {
+            case TETHER_ERROR_NO_CHANGE_TETHERING_PERMISSION:
+                throw new SecurityException("No android.permission.TETHER_PRIVILEGED"
+                        + " or android.permission.WRITE_SETTINGS permission");
+            case TETHER_ERROR_NO_ACCESS_TETHERING_PERMISSION:
+                throw new SecurityException(
+                        "No android.permission.ACCESS_NETWORK_STATE permission");
+        }
+    }
+
+    private class TetheringCallbackInternal extends ITetheringEventCallback.Stub {
+        private volatile int mError = TETHER_ERROR_NO_ERROR;
+        private final ConditionVariable mWaitForCallback = new ConditionVariable();
+
+        @Override
+        public void onCallbackStarted(TetheringCallbackStartedParcel parcel) {
+            mTetheringConfiguration = parcel.config;
+            mTetherStatesParcel = parcel.states;
+            mWaitForCallback.open();
+        }
+
+        @Override
+        public void onCallbackStopped(int errorCode) {
+            mError = errorCode;
+            mWaitForCallback.open();
+        }
+
+        @Override
+        public void onUpstreamChanged(Network network) { }
+
+        @Override
+        public void onConfigurationChanged(TetheringConfigurationParcel config) {
+            mTetheringConfiguration = config;
+        }
+
+        @Override
+        public void onTetherStatesChanged(TetherStatesParcel states) {
+            mTetherStatesParcel = states;
+        }
+
+        @Override
+        public void onTetherClientsChanged(List<TetheredClient> clients) { }
+
+        @Override
+        public void onOffloadStatusChanged(int status) { }
+
+        public void waitForStarted() {
+            mWaitForCallback.block(DEFAULT_TIMEOUT_MS);
+            throwIfPermissionFailure(mError);
+        }
+    }
+
+    /**
+     * Attempt to tether the named interface.  This will setup a dhcp server
+     * on the interface, forward and NAT IP v4 packets and forward DNS requests
+     * to the best active upstream network interface.  Note that if no upstream
+     * IP network interface is available, dhcp will still run and traffic will be
+     * allowed between the tethered devices and this device, though upstream net
+     * access will of course fail until an upstream network interface becomes
+     * active.
+     *
+     * @deprecated The only usages is PanService. It uses this for legacy reasons
+     * and will migrate away as soon as possible.
+     *
+     * @param iface the interface name to tether.
+     * @return error a {@code TETHER_ERROR} value indicating success or failure type
+     *
+     * {@hide}
+     */
+    @Deprecated
+    @SystemApi(client = MODULE_LIBRARIES)
+    public int tether(@NonNull final String iface) {
+        final String callerPkg = mContext.getOpPackageName();
+        Log.i(TAG, "tether caller:" + callerPkg);
+        final RequestDispatcher dispatcher = new RequestDispatcher();
+
+        return dispatcher.waitForResult((connector, listener) -> {
+            try {
+                connector.tether(iface, callerPkg, getAttributionTag(), listener);
+            } catch (RemoteException e) {
+                throw new IllegalStateException(e);
+            }
+        });
+    }
+
+    /**
+     * @return the context's attribution tag
+     */
+    private @Nullable String getAttributionTag() {
+        return null;
+    }
+
+    /**
+     * Stop tethering the named interface.
+     *
+     * @deprecated The only usages is PanService. It uses this for legacy reasons
+     * and will migrate away as soon as possible.
+     *
+     * {@hide}
+     */
+    @Deprecated
+    @SystemApi(client = MODULE_LIBRARIES)
+    public int untether(@NonNull final String iface) {
+        final String callerPkg = mContext.getOpPackageName();
+        Log.i(TAG, "untether caller:" + callerPkg);
+
+        final RequestDispatcher dispatcher = new RequestDispatcher();
+
+        return dispatcher.waitForResult((connector, listener) -> {
+            try {
+                connector.untether(iface, callerPkg, getAttributionTag(), listener);
+            } catch (RemoteException e) {
+                throw new IllegalStateException(e);
+            }
+        });
+    }
+
+    /**
+     * Attempt to both alter the mode of USB and Tethering of USB.
+     *
+     * @deprecated New client should not use this API anymore. All clients should use
+     * #startTethering or #stopTethering which encapsulate proper entitlement logic. If the API is
+     * used and an entitlement check is needed, downstream USB tethering will be enabled but will
+     * not have any upstream.
+     *
+     * {@hide}
+     */
+    @Deprecated
+    @SystemApi(client = MODULE_LIBRARIES)
+    public int setUsbTethering(final boolean enable) {
+        final String callerPkg = mContext.getOpPackageName();
+        Log.i(TAG, "setUsbTethering caller:" + callerPkg);
+
+        final RequestDispatcher dispatcher = new RequestDispatcher();
+
+        return dispatcher.waitForResult((connector, listener) -> {
+            try {
+                connector.setUsbTethering(enable, callerPkg, getAttributionTag(),
+                        listener);
+            } catch (RemoteException e) {
+                throw new IllegalStateException(e);
+            }
+        });
+    }
+
+    /**
+     *  Use with {@link #startTethering} to specify additional parameters when starting tethering.
+     */
+    public static class TetheringRequest {
+        /** A configuration set for TetheringRequest. */
+        private final TetheringRequestParcel mRequestParcel;
+
+        private TetheringRequest(final TetheringRequestParcel request) {
+            mRequestParcel = request;
+        }
+
+        /** Builder used to create TetheringRequest. */
+        public static class Builder {
+            private final TetheringRequestParcel mBuilderParcel;
+
+            /** Default constructor of Builder. */
+            public Builder(@TetheringType final int type) {
+                mBuilderParcel = new TetheringRequestParcel();
+                mBuilderParcel.tetheringType = type;
+                mBuilderParcel.localIPv4Address = null;
+                mBuilderParcel.staticClientAddress = null;
+                mBuilderParcel.exemptFromEntitlementCheck = false;
+                mBuilderParcel.showProvisioningUi = true;
+            }
+
+            /**
+             * Configure tethering with static IPv4 assignment.
+             *
+             * A DHCP server will be started, but will only be able to offer the client address.
+             * The two addresses must be in the same prefix.
+             *
+             * @param localIPv4Address The preferred local IPv4 link address to use.
+             * @param clientAddress The static client address.
+             */
+            @RequiresPermission(android.Manifest.permission.TETHER_PRIVILEGED)
+            @NonNull
+            public Builder setStaticIpv4Addresses(@NonNull final LinkAddress localIPv4Address,
+                    @NonNull final LinkAddress clientAddress) {
+                Objects.requireNonNull(localIPv4Address);
+                Objects.requireNonNull(clientAddress);
+                if (!checkStaticAddressConfiguration(localIPv4Address, clientAddress)) {
+                    throw new IllegalArgumentException("Invalid server or client addresses");
+                }
+
+                mBuilderParcel.localIPv4Address = localIPv4Address;
+                mBuilderParcel.staticClientAddress = clientAddress;
+                return this;
+            }
+
+            /** Start tethering without entitlement checks. */
+            @RequiresPermission(android.Manifest.permission.TETHER_PRIVILEGED)
+            @NonNull
+            public Builder setExemptFromEntitlementCheck(boolean exempt) {
+                mBuilderParcel.exemptFromEntitlementCheck = exempt;
+                return this;
+            }
+
+            /**
+             * If an entitlement check is needed, sets whether to show the entitlement UI or to
+             * perform a silent entitlement check. By default, the entitlement UI is shown.
+             */
+            @RequiresPermission(android.Manifest.permission.TETHER_PRIVILEGED)
+            @NonNull
+            public Builder setShouldShowEntitlementUi(boolean showUi) {
+                mBuilderParcel.showProvisioningUi = showUi;
+                return this;
+            }
+
+            /** Build {@link TetheringRequest] with the currently set configuration. */
+            @NonNull
+            public TetheringRequest build() {
+                return new TetheringRequest(mBuilderParcel);
+            }
+        }
+
+        /**
+         * Get the local IPv4 address, if one was configured with
+         * {@link Builder#setStaticIpv4Addresses}.
+         */
+        @Nullable
+        public LinkAddress getLocalIpv4Address() {
+            return mRequestParcel.localIPv4Address;
+        }
+
+        /**
+         * Get the static IPv4 address of the client, if one was configured with
+         * {@link Builder#setStaticIpv4Addresses}.
+         */
+        @Nullable
+        public LinkAddress getClientStaticIpv4Address() {
+            return mRequestParcel.staticClientAddress;
+        }
+
+        /** Get tethering type. */
+        @TetheringType
+        public int getTetheringType() {
+            return mRequestParcel.tetheringType;
+        }
+
+        /** Check if exempt from entitlement check. */
+        public boolean isExemptFromEntitlementCheck() {
+            return mRequestParcel.exemptFromEntitlementCheck;
+        }
+
+        /** Check if show entitlement ui.  */
+        public boolean getShouldShowEntitlementUi() {
+            return mRequestParcel.showProvisioningUi;
+        }
+
+        /**
+         * Check whether the two addresses are ipv4 and in the same prefix.
+         * @hide
+         */
+        public static boolean checkStaticAddressConfiguration(
+                @NonNull final LinkAddress localIPv4Address,
+                @NonNull final LinkAddress clientAddress) {
+            return localIPv4Address.getPrefixLength() == clientAddress.getPrefixLength()
+                    && localIPv4Address.isIpv4() && clientAddress.isIpv4()
+                    && new IpPrefix(localIPv4Address.toString()).equals(
+                    new IpPrefix(clientAddress.toString()));
+        }
+
+        /**
+         * Get a TetheringRequestParcel from the configuration
+         * @hide
+         */
+        public TetheringRequestParcel getParcel() {
+            return mRequestParcel;
+        }
+
+        /** String of TetheringRequest detail. */
+        public String toString() {
+            return "TetheringRequest [ type= " + mRequestParcel.tetheringType
+                    + ", localIPv4Address= " + mRequestParcel.localIPv4Address
+                    + ", staticClientAddress= " + mRequestParcel.staticClientAddress
+                    + ", exemptFromEntitlementCheck= "
+                    + mRequestParcel.exemptFromEntitlementCheck + ", showProvisioningUi= "
+                    + mRequestParcel.showProvisioningUi + " ]";
+        }
+    }
+
+    /**
+     * Callback for use with {@link #startTethering} to find out whether tethering succeeded.
+     */
+    public interface StartTetheringCallback {
+        /**
+         * Called when tethering has been successfully started.
+         */
+        default void onTetheringStarted() {}
+
+        /**
+         * Called when starting tethering failed.
+         *
+         * @param error The error that caused the failure.
+         */
+        default void onTetheringFailed(@StartTetheringError final int error) {}
+    }
+
+    /**
+     * Starts tethering and runs tether provisioning for the given type if needed. If provisioning
+     * fails, stopTethering will be called automatically.
+     *
+     * <p>Without {@link android.Manifest.permission.TETHER_PRIVILEGED} permission, the call will
+     * fail if a tethering entitlement check is required.
+     *
+     * @param request a {@link TetheringRequest} which can specify the preferred configuration.
+     * @param executor {@link Executor} to specify the thread upon which the callback of
+     *         TetheringRequest will be invoked.
+     * @param callback A callback that will be called to indicate the success status of the
+     *                 tethering start request.
+     */
+    @RequiresPermission(anyOf = {
+            android.Manifest.permission.TETHER_PRIVILEGED,
+            android.Manifest.permission.WRITE_SETTINGS
+    })
+    public void startTethering(@NonNull final TetheringRequest request,
+            @NonNull final Executor executor, @NonNull final StartTetheringCallback callback) {
+        final String callerPkg = mContext.getOpPackageName();
+        Log.i(TAG, "startTethering caller:" + callerPkg);
+
+        final IIntResultListener listener = new IIntResultListener.Stub() {
+            @Override
+            public void onResult(final int resultCode) {
+                executor.execute(() -> {
+                    if (resultCode == TETHER_ERROR_NO_ERROR) {
+                        callback.onTetheringStarted();
+                    } else {
+                        callback.onTetheringFailed(resultCode);
+                    }
+                });
+            }
+        };
+        getConnector(c -> c.startTethering(request.getParcel(), callerPkg,
+                getAttributionTag(), listener));
+    }
+
+    /**
+     * Starts tethering and runs tether provisioning for the given type if needed. If provisioning
+     * fails, stopTethering will be called automatically.
+     *
+     * <p>Without {@link android.Manifest.permission.TETHER_PRIVILEGED} permission, the call will
+     * fail if a tethering entitlement check is required.
+     *
+     * @param type The tethering type, on of the {@code TetheringManager#TETHERING_*} constants.
+     * @param executor {@link Executor} to specify the thread upon which the callback of
+     *         TetheringRequest will be invoked.
+     * @hide
+     */
+    @RequiresPermission(anyOf = {
+            android.Manifest.permission.TETHER_PRIVILEGED,
+            android.Manifest.permission.WRITE_SETTINGS
+    })
+    @SystemApi(client = MODULE_LIBRARIES)
+    public void startTethering(int type, @NonNull final Executor executor,
+            @NonNull final StartTetheringCallback callback) {
+        startTethering(new TetheringRequest.Builder(type).build(), executor, callback);
+    }
+
+    /**
+     * Stops tethering for the given type. Also cancels any provisioning rechecks for that type if
+     * applicable.
+     *
+     * <p>Without {@link android.Manifest.permission.TETHER_PRIVILEGED} permission, the call will
+     * fail if a tethering entitlement check is required.
+     */
+    @RequiresPermission(anyOf = {
+            android.Manifest.permission.TETHER_PRIVILEGED,
+            android.Manifest.permission.WRITE_SETTINGS
+    })
+    public void stopTethering(@TetheringType final int type) {
+        final String callerPkg = mContext.getOpPackageName();
+        Log.i(TAG, "stopTethering caller:" + callerPkg);
+
+        getConnector(c -> c.stopTethering(type, callerPkg, getAttributionTag(),
+                new IIntResultListener.Stub() {
+            @Override
+            public void onResult(int resultCode) {
+                // TODO: provide an API to obtain result
+                // This has never been possible as stopTethering has always been void and never
+                // taken a callback object. The only indication that callers have is if the call
+                // results in a TETHER_STATE_CHANGE broadcast.
+            }
+        }));
+    }
+
+    /**
+     * Callback for use with {@link #getLatestTetheringEntitlementResult} to find out whether
+     * entitlement succeeded.
+     */
+    public interface OnTetheringEntitlementResultListener  {
+        /**
+         * Called to notify entitlement result.
+         *
+         * @param resultCode an int value of entitlement result. It may be one of
+         *         {@link #TETHER_ERROR_NO_ERROR},
+         *         {@link #TETHER_ERROR_PROVISIONING_FAILED}, or
+         *         {@link #TETHER_ERROR_ENTITLEMENT_UNKNOWN}.
+         */
+        void onTetheringEntitlementResult(@EntitlementResult int result);
+    }
+
+    /**
+     * Request the latest value of the tethering entitlement check.
+     *
+     * <p>This method will only return the latest entitlement result if it is available. If no
+     * cached entitlement result is available, and {@code showEntitlementUi} is false,
+     * {@link #TETHER_ERROR_ENTITLEMENT_UNKNOWN} will be returned. If {@code showEntitlementUi} is
+     * true, entitlement will be run.
+     *
+     * <p>Without {@link android.Manifest.permission.TETHER_PRIVILEGED} permission, the call will
+     * fail if a tethering entitlement check is required.
+     *
+     * @param type the downstream type of tethering. Must be one of {@code #TETHERING_*} constants.
+     * @param showEntitlementUi a boolean indicating whether to check result for the UI-based
+     *         entitlement check or the silent entitlement check.
+     * @param executor the executor on which callback will be invoked.
+     * @param listener an {@link OnTetheringEntitlementResultListener} which will be called to
+     *         notify the caller of the result of entitlement check. The listener may be called zero
+     *         or one time.
+     */
+    @RequiresPermission(anyOf = {
+            android.Manifest.permission.TETHER_PRIVILEGED,
+            android.Manifest.permission.WRITE_SETTINGS
+    })
+    public void requestLatestTetheringEntitlementResult(@TetheringType int type,
+            boolean showEntitlementUi,
+            @NonNull Executor executor,
+            @NonNull final OnTetheringEntitlementResultListener listener) {
+        if (listener == null) {
+            throw new IllegalArgumentException(
+                    "OnTetheringEntitlementResultListener cannot be null.");
+        }
+
+        ResultReceiver wrappedListener = new ResultReceiver(null /* handler */) {
+            @Override
+            protected void onReceiveResult(int resultCode, Bundle resultData) {
+                executor.execute(() -> {
+                    listener.onTetheringEntitlementResult(resultCode);
+                });
+            }
+        };
+
+        requestLatestTetheringEntitlementResult(type, wrappedListener,
+                    showEntitlementUi);
+    }
+
+    /**
+     * Helper function of #requestLatestTetheringEntitlementResult to remain backwards compatible
+     * with ConnectivityManager#getLatestTetheringEntitlementResult
+     *
+     * {@hide}
+     */
+    // TODO: improve the usage of ResultReceiver, b/145096122
+    @SystemApi(client = MODULE_LIBRARIES)
+    public void requestLatestTetheringEntitlementResult(@TetheringType final int type,
+            @NonNull final ResultReceiver receiver, final boolean showEntitlementUi) {
+        final String callerPkg = mContext.getOpPackageName();
+        Log.i(TAG, "getLatestTetheringEntitlementResult caller:" + callerPkg);
+
+        getConnector(c -> c.requestLatestTetheringEntitlementResult(
+                type, receiver, showEntitlementUi, callerPkg, getAttributionTag()));
+    }
+
+    /**
+     * Callback for use with {@link registerTetheringEventCallback} to find out tethering
+     * upstream status.
+     */
+    public interface TetheringEventCallback {
+        /**
+         * Called when tethering supported status changed.
+         *
+         * <p>This will be called immediately after the callback is registered, and may be called
+         * multiple times later upon changes.
+         *
+         * <p>Tethering may be disabled via system properties, device configuration, or device
+         * policy restrictions.
+         *
+         * @param supported The new supported status
+         */
+        default void onTetheringSupported(boolean supported) {}
+
+        /**
+         * Called when tethering upstream changed.
+         *
+         * <p>This will be called immediately after the callback is registered, and may be called
+         * multiple times later upon changes.
+         *
+         * @param network the {@link Network} of tethering upstream. Null means tethering doesn't
+         * have any upstream.
+         */
+        default void onUpstreamChanged(@Nullable Network network) {}
+
+        /**
+         * Called when there was a change in tethering interface regular expressions.
+         *
+         * <p>This will be called immediately after the callback is registered, and may be called
+         * multiple times later upon changes.
+         * @param reg The new regular expressions.
+         *
+         * @hide
+         */
+        @SystemApi(client = MODULE_LIBRARIES)
+        default void onTetherableInterfaceRegexpsChanged(@NonNull TetheringInterfaceRegexps reg) {}
+
+        /**
+         * Called when there was a change in the list of tetherable interfaces. Tetherable
+         * interface means this interface is available and can be used for tethering.
+         *
+         * <p>This will be called immediately after the callback is registered, and may be called
+         * multiple times later upon changes.
+         * @param interfaces The list of tetherable interface names.
+         */
+        default void onTetherableInterfacesChanged(@NonNull List<String> interfaces) {}
+
+        /**
+         * Called when there was a change in the list of tethered interfaces.
+         *
+         * <p>This will be called immediately after the callback is registered, and may be called
+         * multiple times later upon changes.
+         * @param interfaces The list of 0 or more String of currently tethered interface names.
+         */
+        default void onTetheredInterfacesChanged(@NonNull List<String> interfaces) {}
+
+        /**
+         * Called when an error occurred configuring tethering.
+         *
+         * <p>This will be called immediately after the callback is registered if the latest status
+         * on the interface is an error, and may be called multiple times later upon changes.
+         * @param ifName Name of the interface.
+         * @param error One of {@code TetheringManager#TETHER_ERROR_*}.
+         */
+        default void onError(@NonNull String ifName, @TetheringIfaceError int error) {}
+
+        /**
+         * Called when the list of tethered clients changes.
+         *
+         * <p>This callback provides best-effort information on connected clients based on state
+         * known to the system, however the list cannot be completely accurate (and should not be
+         * used for security purposes). For example, clients behind a bridge and using static IP
+         * assignments are not visible to the tethering device; or even when using DHCP, such
+         * clients may still be reported by this callback after disconnection as the system cannot
+         * determine if they are still connected.
+         * @param clients The new set of tethered clients; the collection is not ordered.
+         */
+        default void onClientsChanged(@NonNull Collection<TetheredClient> clients) {}
+
+        /**
+         * Called when tethering offload status changes.
+         *
+         * <p>This will be called immediately after the callback is registered.
+         * @param status The offload status.
+         */
+        default void onOffloadStatusChanged(@TetherOffloadStatus int status) {}
+    }
+
+    /**
+     * Regular expressions used to identify tethering interfaces.
+     * @hide
+     */
+    @SystemApi(client = MODULE_LIBRARIES)
+    public static class TetheringInterfaceRegexps {
+        private final String[] mTetherableBluetoothRegexs;
+        private final String[] mTetherableUsbRegexs;
+        private final String[] mTetherableWifiRegexs;
+
+        /** @hide */
+        public TetheringInterfaceRegexps(@NonNull String[] tetherableBluetoothRegexs,
+                @NonNull String[] tetherableUsbRegexs, @NonNull String[] tetherableWifiRegexs) {
+            mTetherableBluetoothRegexs = tetherableBluetoothRegexs.clone();
+            mTetherableUsbRegexs = tetherableUsbRegexs.clone();
+            mTetherableWifiRegexs = tetherableWifiRegexs.clone();
+        }
+
+        @NonNull
+        public List<String> getTetherableBluetoothRegexs() {
+            return Collections.unmodifiableList(Arrays.asList(mTetherableBluetoothRegexs));
+        }
+
+        @NonNull
+        public List<String> getTetherableUsbRegexs() {
+            return Collections.unmodifiableList(Arrays.asList(mTetherableUsbRegexs));
+        }
+
+        @NonNull
+        public List<String> getTetherableWifiRegexs() {
+            return Collections.unmodifiableList(Arrays.asList(mTetherableWifiRegexs));
+        }
+
+        @Override
+        public int hashCode() {
+            return Objects.hash(mTetherableBluetoothRegexs, mTetherableUsbRegexs,
+                    mTetherableWifiRegexs);
+        }
+
+        @Override
+        public boolean equals(@Nullable Object obj) {
+            if (!(obj instanceof TetheringInterfaceRegexps)) return false;
+            final TetheringInterfaceRegexps other = (TetheringInterfaceRegexps) obj;
+            return Arrays.equals(mTetherableBluetoothRegexs, other.mTetherableBluetoothRegexs)
+                    && Arrays.equals(mTetherableUsbRegexs, other.mTetherableUsbRegexs)
+                    && Arrays.equals(mTetherableWifiRegexs, other.mTetherableWifiRegexs);
+        }
+    }
+
+    /**
+     * Start listening to tethering change events. Any new added callback will receive the last
+     * tethering status right away. If callback is registered,
+     * {@link TetheringEventCallback#onUpstreamChanged} will immediately be called. If tethering
+     * has no upstream or disabled, the argument of callback will be null. The same callback object
+     * cannot be registered twice.
+     *
+     * @param executor the executor on which callback will be invoked.
+     * @param callback the callback to be called when tethering has change events.
+     */
+    @RequiresPermission(Manifest.permission.ACCESS_NETWORK_STATE)
+    public void registerTetheringEventCallback(@NonNull Executor executor,
+            @NonNull TetheringEventCallback callback) {
+        final String callerPkg = mContext.getOpPackageName();
+        Log.i(TAG, "registerTetheringEventCallback caller:" + callerPkg);
+
+        synchronized (mTetheringEventCallbacks) {
+            if (mTetheringEventCallbacks.containsKey(callback)) {
+                throw new IllegalArgumentException("callback was already registered.");
+            }
+            final ITetheringEventCallback remoteCallback = new ITetheringEventCallback.Stub() {
+                // Only accessed with a lock on this object
+                private final HashMap<String, Integer> mErrorStates = new HashMap<>();
+                private String[] mLastTetherableInterfaces = null;
+                private String[] mLastTetheredInterfaces = null;
+
+                @Override
+                public void onUpstreamChanged(Network network) throws RemoteException {
+                    executor.execute(() -> {
+                        callback.onUpstreamChanged(network);
+                    });
+                }
+
+                private synchronized void sendErrorCallbacks(final TetherStatesParcel newStates) {
+                    for (int i = 0; i < newStates.erroredIfaceList.length; i++) {
+                        final String iface = newStates.erroredIfaceList[i];
+                        final Integer lastError = mErrorStates.get(iface);
+                        final int newError = newStates.lastErrorList[i];
+                        if (newError != TETHER_ERROR_NO_ERROR
+                                && !Objects.equals(lastError, newError)) {
+                            callback.onError(iface, newError);
+                        }
+                        mErrorStates.put(iface, newError);
+                    }
+                }
+
+                private synchronized void maybeSendTetherableIfacesChangedCallback(
+                        final TetherStatesParcel newStates) {
+                    if (Arrays.equals(mLastTetherableInterfaces, newStates.availableList)) return;
+                    mLastTetherableInterfaces = newStates.availableList.clone();
+                    callback.onTetherableInterfacesChanged(
+                            Collections.unmodifiableList(Arrays.asList(mLastTetherableInterfaces)));
+                }
+
+                private synchronized void maybeSendTetheredIfacesChangedCallback(
+                        final TetherStatesParcel newStates) {
+                    if (Arrays.equals(mLastTetheredInterfaces, newStates.tetheredList)) return;
+                    mLastTetheredInterfaces = newStates.tetheredList.clone();
+                    callback.onTetheredInterfacesChanged(
+                            Collections.unmodifiableList(Arrays.asList(mLastTetheredInterfaces)));
+                }
+
+                // Called immediately after the callbacks are registered.
+                @Override
+                public void onCallbackStarted(TetheringCallbackStartedParcel parcel) {
+                    executor.execute(() -> {
+                        callback.onTetheringSupported(parcel.tetheringSupported);
+                        callback.onUpstreamChanged(parcel.upstreamNetwork);
+                        sendErrorCallbacks(parcel.states);
+                        sendRegexpsChanged(parcel.config);
+                        maybeSendTetherableIfacesChangedCallback(parcel.states);
+                        maybeSendTetheredIfacesChangedCallback(parcel.states);
+                        callback.onClientsChanged(parcel.tetheredClients);
+                        callback.onOffloadStatusChanged(parcel.offloadStatus);
+                    });
+                }
+
+                @Override
+                public void onCallbackStopped(int errorCode) {
+                    executor.execute(() -> {
+                        throwIfPermissionFailure(errorCode);
+                    });
+                }
+
+                private void sendRegexpsChanged(TetheringConfigurationParcel parcel) {
+                    callback.onTetherableInterfaceRegexpsChanged(new TetheringInterfaceRegexps(
+                            parcel.tetherableBluetoothRegexs,
+                            parcel.tetherableUsbRegexs,
+                            parcel.tetherableWifiRegexs));
+                }
+
+                @Override
+                public void onConfigurationChanged(TetheringConfigurationParcel config) {
+                    executor.execute(() -> sendRegexpsChanged(config));
+                }
+
+                @Override
+                public void onTetherStatesChanged(TetherStatesParcel states) {
+                    executor.execute(() -> {
+                        sendErrorCallbacks(states);
+                        maybeSendTetherableIfacesChangedCallback(states);
+                        maybeSendTetheredIfacesChangedCallback(states);
+                    });
+                }
+
+                @Override
+                public void onTetherClientsChanged(final List<TetheredClient> clients) {
+                    executor.execute(() -> callback.onClientsChanged(clients));
+                }
+
+                @Override
+                public void onOffloadStatusChanged(final int status) {
+                    executor.execute(() -> callback.onOffloadStatusChanged(status));
+                }
+            };
+            getConnector(c -> c.registerTetheringEventCallback(remoteCallback, callerPkg));
+            mTetheringEventCallbacks.put(callback, remoteCallback);
+        }
+    }
+
+    /**
+     * Remove tethering event callback previously registered with
+     * {@link #registerTetheringEventCallback}.
+     *
+     * @param callback previously registered callback.
+     */
+    @RequiresPermission(anyOf = {
+            Manifest.permission.TETHER_PRIVILEGED,
+            Manifest.permission.ACCESS_NETWORK_STATE
+    })
+    public void unregisterTetheringEventCallback(@NonNull final TetheringEventCallback callback) {
+        final String callerPkg = mContext.getOpPackageName();
+        Log.i(TAG, "unregisterTetheringEventCallback caller:" + callerPkg);
+
+        synchronized (mTetheringEventCallbacks) {
+            ITetheringEventCallback remoteCallback = mTetheringEventCallbacks.remove(callback);
+            if (remoteCallback == null) {
+                throw new IllegalArgumentException("callback was not registered.");
+            }
+
+            getConnector(c -> c.unregisterTetheringEventCallback(remoteCallback, callerPkg));
+        }
+    }
+
+    /**
+     * Get a more detailed error code after a Tethering or Untethering
+     * request asynchronously failed.
+     *
+     * @param iface The name of the interface of interest
+     * @return error The error code of the last error tethering or untethering the named
+     *               interface
+     * @hide
+     */
+    @SystemApi(client = MODULE_LIBRARIES)
+    public int getLastTetherError(@NonNull final String iface) {
+        mCallback.waitForStarted();
+        if (mTetherStatesParcel == null) return TETHER_ERROR_NO_ERROR;
+
+        int i = 0;
+        for (String errored : mTetherStatesParcel.erroredIfaceList) {
+            if (iface.equals(errored)) return mTetherStatesParcel.lastErrorList[i];
+
+            i++;
+        }
+        return TETHER_ERROR_NO_ERROR;
+    }
+
+    /**
+     * Get the list of regular expressions that define any tetherable
+     * USB network interfaces.  If USB tethering is not supported by the
+     * device, this list should be empty.
+     *
+     * @return an array of 0 or more regular expression Strings defining
+     *        what interfaces are considered tetherable usb interfaces.
+     * @hide
+     */
+    @SystemApi(client = MODULE_LIBRARIES)
+    public @NonNull String[] getTetherableUsbRegexs() {
+        mCallback.waitForStarted();
+        return mTetheringConfiguration.tetherableUsbRegexs;
+    }
+
+    /**
+     * Get the list of regular expressions that define any tetherable
+     * Wifi network interfaces.  If Wifi tethering is not supported by the
+     * device, this list should be empty.
+     *
+     * @return an array of 0 or more regular expression Strings defining
+     *        what interfaces are considered tetherable wifi interfaces.
+     * @hide
+     */
+    @SystemApi(client = MODULE_LIBRARIES)
+    public @NonNull String[] getTetherableWifiRegexs() {
+        mCallback.waitForStarted();
+        return mTetheringConfiguration.tetherableWifiRegexs;
+    }
+
+    /**
+     * Get the list of regular expressions that define any tetherable
+     * Bluetooth network interfaces.  If Bluetooth tethering is not supported by the
+     * device, this list should be empty.
+     *
+     * @return an array of 0 or more regular expression Strings defining
+     *        what interfaces are considered tetherable bluetooth interfaces.
+     * @hide
+     */
+    @SystemApi(client = MODULE_LIBRARIES)
+    public @NonNull String[] getTetherableBluetoothRegexs() {
+        mCallback.waitForStarted();
+        return mTetheringConfiguration.tetherableBluetoothRegexs;
+    }
+
+    /**
+     * Get the set of tetherable, available interfaces.  This list is limited by
+     * device configuration and current interface existence.
+     *
+     * @return an array of 0 or more Strings of tetherable interface names.
+     * @hide
+     */
+    @SystemApi(client = MODULE_LIBRARIES)
+    public @NonNull String[] getTetherableIfaces() {
+        mCallback.waitForStarted();
+        if (mTetherStatesParcel == null) return new String[0];
+
+        return mTetherStatesParcel.availableList;
+    }
+
+    /**
+     * Get the set of tethered interfaces.
+     *
+     * @return an array of 0 or more String of currently tethered interface names.
+     * @hide
+     */
+    @SystemApi(client = MODULE_LIBRARIES)
+    public @NonNull String[] getTetheredIfaces() {
+        mCallback.waitForStarted();
+        if (mTetherStatesParcel == null) return new String[0];
+
+        return mTetherStatesParcel.tetheredList;
+    }
+
+    /**
+     * Get the set of interface names which attempted to tether but
+     * failed.  Re-attempting to tether may cause them to reset to the Tethered
+     * state.  Alternatively, causing the interface to be destroyed and recreated
+     * may cause them to reset to the available state.
+     * {@link TetheringManager#getLastTetherError} can be used to get more
+     * information on the cause of the errors.
+     *
+     * @return an array of 0 or more String indicating the interface names
+     *        which failed to tether.
+     * @hide
+     */
+    @SystemApi(client = MODULE_LIBRARIES)
+    public @NonNull String[] getTetheringErroredIfaces() {
+        mCallback.waitForStarted();
+        if (mTetherStatesParcel == null) return new String[0];
+
+        return mTetherStatesParcel.erroredIfaceList;
+    }
+
+    /**
+     * Get the set of tethered dhcp ranges.
+     *
+     * @deprecated This API just return the default value which is not used in DhcpServer.
+     * @hide
+     */
+    @Deprecated
+    public @NonNull String[] getTetheredDhcpRanges() {
+        mCallback.waitForStarted();
+        return mTetheringConfiguration.legacyDhcpRanges;
+    }
+
+    /**
+     * Check if the device allows for tethering.  It may be disabled via
+     * {@code ro.tether.denied} system property, Settings.TETHER_SUPPORTED or
+     * due to device configuration.
+     *
+     * @return a boolean - {@code true} indicating Tethering is supported.
+     * @hide
+     */
+    @SystemApi(client = MODULE_LIBRARIES)
+    public boolean isTetheringSupported() {
+        final String callerPkg = mContext.getOpPackageName();
+
+        return isTetheringSupported(callerPkg);
+    }
+
+    /**
+     * Check if the device allows for tethering. It may be disabled via {@code ro.tether.denied}
+     * system property, Settings.TETHER_SUPPORTED or due to device configuration. This is useful
+     * for system components that query this API on behalf of an app. In particular, Bluetooth
+     * has @UnsupportedAppUsage calls that will let apps turn on bluetooth tethering if they have
+     * the right permissions, but such an app needs to know whether it can (permissions as well
+     * as support from the device) turn on tethering in the first place to show the appropriate UI.
+     *
+     * @param callerPkg The caller package name, if it is not matching the calling uid,
+     *       SecurityException would be thrown.
+     * @return a boolean - {@code true} indicating Tethering is supported.
+     * @hide
+     */
+    @SystemApi(client = MODULE_LIBRARIES)
+    public boolean isTetheringSupported(@NonNull final String callerPkg) {
+
+        final RequestDispatcher dispatcher = new RequestDispatcher();
+        final int ret = dispatcher.waitForResult((connector, listener) -> {
+            try {
+                connector.isTetheringSupported(callerPkg, getAttributionTag(), listener);
+            } catch (RemoteException e) {
+                throw new IllegalStateException(e);
+            }
+        });
+
+        return ret == TETHER_ERROR_NO_ERROR;
+    }
+
+    /**
+     * Stop all active tethering.
+     *
+     * <p>Without {@link android.Manifest.permission.TETHER_PRIVILEGED} permission, the call will
+     * fail if a tethering entitlement check is required.
+     */
+    @RequiresPermission(anyOf = {
+            android.Manifest.permission.TETHER_PRIVILEGED,
+            android.Manifest.permission.WRITE_SETTINGS
+    })
+    public void stopAllTethering() {
+        final String callerPkg = mContext.getOpPackageName();
+        Log.i(TAG, "stopAllTethering caller:" + callerPkg);
+
+        getConnector(c -> c.stopAllTethering(callerPkg, getAttributionTag(),
+                new IIntResultListener.Stub() {
+                    @Override
+                    public void onResult(int resultCode) {
+                        // TODO: add an API parameter to send result to caller.
+                        // This has never been possible as stopAllTethering has always been void
+                        // and never taken a callback object. The only indication that callers have
+                        // is if the call results in a TETHER_STATE_CHANGE broadcast.
+                    }
+                }));
+    }
+}
diff --git a/Tethering/common/TetheringLib/src/android/net/TetheringRequestParcel.aidl b/Tethering/common/TetheringLib/src/android/net/TetheringRequestParcel.aidl
new file mode 100644
index 0000000..c0280d3
--- /dev/null
+++ b/Tethering/common/TetheringLib/src/android/net/TetheringRequestParcel.aidl
@@ -0,0 +1,31 @@
+/*
+ * Copyright (C) 2020 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package android.net;
+
+import android.net.LinkAddress;
+
+/**
+ * Configuration details for requesting tethering.
+ * @hide
+ */
+parcelable TetheringRequestParcel {
+    int tetheringType;
+    LinkAddress localIPv4Address;
+    LinkAddress staticClientAddress;
+    boolean exemptFromEntitlementCheck;
+    boolean showProvisioningUi;
+}
diff --git a/Tethering/jarjar-rules.txt b/Tethering/jarjar-rules.txt
new file mode 100644
index 0000000..591861f
--- /dev/null
+++ b/Tethering/jarjar-rules.txt
@@ -0,0 +1,11 @@
+# These must be kept in sync with the framework-tethering-shared-srcs filegroup.
+# Classes from the framework-tethering-shared-srcs filegroup.
+# If there are files in that filegroup that are not covered below, the classes in the
+# module will be overwritten by the ones in the framework.
+rule com.android.internal.util.** com.android.networkstack.tethering.util.@1
+rule android.util.LocalLog* com.android.networkstack.tethering.util.LocalLog@1
+
+rule android.net.shared.Inet4AddressUtils* com.android.networkstack.tethering.shared.Inet4AddressUtils@1
+
+# Classes from net-utils-framework-common
+rule com.android.net.module.util.** com.android.networkstack.tethering.util.@1
\ No newline at end of file
diff --git a/Tethering/jni/android_net_util_TetheringUtils.cpp b/Tethering/jni/android_net_util_TetheringUtils.cpp
new file mode 100644
index 0000000..94c871d
--- /dev/null
+++ b/Tethering/jni/android_net_util_TetheringUtils.cpp
@@ -0,0 +1,201 @@
+/*
+ * Copyright (C) 2017 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include <errno.h>
+#include <error.h>
+#include <jni.h>
+#include <linux/filter.h>
+#include <nativehelper/JNIHelp.h>
+#include <nativehelper/JNIHelpCompat.h>
+#include <nativehelper/ScopedUtfChars.h>
+#include <net/if.h>
+#include <netinet/ether.h>
+#include <netinet/ip6.h>
+#include <netinet/icmp6.h>
+#include <sys/socket.h>
+#include <stdio.h>
+
+#define LOG_TAG "TetheringUtils"
+#include <android/log.h>
+
+namespace android {
+
+static const uint32_t kIPv6NextHeaderOffset = offsetof(ip6_hdr, ip6_nxt);
+static const uint32_t kIPv6PayloadStart = sizeof(ip6_hdr);
+static const uint32_t kICMPv6TypeOffset = kIPv6PayloadStart + offsetof(icmp6_hdr, icmp6_type);
+
+static void android_net_util_setupIcmpFilter(JNIEnv *env, jobject javaFd, uint32_t type) {
+    sock_filter filter_code[] = {
+        // Check header is ICMPv6.
+        BPF_STMT(BPF_LD  | BPF_B   | BPF_ABS,  kIPv6NextHeaderOffset),
+        BPF_JUMP(BPF_JMP | BPF_JEQ | BPF_K,    IPPROTO_ICMPV6, 0, 3),
+
+        // Check ICMPv6 type.
+        BPF_STMT(BPF_LD  | BPF_B   | BPF_ABS,  kICMPv6TypeOffset),
+        BPF_JUMP(BPF_JMP | BPF_JEQ | BPF_K,    type, 0, 1),
+
+        // Accept or reject.
+        BPF_STMT(BPF_RET | BPF_K,              0xffff),
+        BPF_STMT(BPF_RET | BPF_K,              0)
+    };
+
+    const sock_fprog filter = {
+        sizeof(filter_code) / sizeof(filter_code[0]),
+        filter_code,
+    };
+
+    int fd = jniGetFDFromFileDescriptor(env, javaFd);
+    if (setsockopt(fd, SOL_SOCKET, SO_ATTACH_FILTER, &filter, sizeof(filter)) != 0) {
+        jniThrowExceptionFmt(env, "java/net/SocketException",
+                "setsockopt(SO_ATTACH_FILTER): %s", strerror(errno));
+    }
+}
+
+static void android_net_util_setupNaSocket(JNIEnv *env, jobject clazz, jobject javaFd)
+{
+    android_net_util_setupIcmpFilter(env, javaFd, ND_NEIGHBOR_ADVERT);
+}
+
+static void android_net_util_setupNsSocket(JNIEnv *env, jobject clazz, jobject javaFd)
+{
+    android_net_util_setupIcmpFilter(env, javaFd, ND_NEIGHBOR_SOLICIT);
+}
+
+static void android_net_util_setupRaSocket(JNIEnv *env, jobject clazz, jobject javaFd,
+        jint ifIndex)
+{
+    static const int kLinkLocalHopLimit = 255;
+
+    int fd = jniGetFDFromFileDescriptor(env, javaFd);
+
+    // Set an ICMPv6 filter that only passes Router Solicitations.
+    struct icmp6_filter rs_only;
+    ICMP6_FILTER_SETBLOCKALL(&rs_only);
+    ICMP6_FILTER_SETPASS(ND_ROUTER_SOLICIT, &rs_only);
+    socklen_t len = sizeof(rs_only);
+    if (setsockopt(fd, IPPROTO_ICMPV6, ICMP6_FILTER, &rs_only, len) != 0) {
+        jniThrowExceptionFmt(env, "java/net/SocketException",
+                "setsockopt(ICMP6_FILTER): %s", strerror(errno));
+        return;
+    }
+
+    // Most/all of the rest of these options can be set via Java code, but
+    // because we're here on account of setting an icmp6_filter go ahead
+    // and do it all natively for now.
+
+    // Set the multicast hoplimit to 255 (link-local only).
+    int hops = kLinkLocalHopLimit;
+    len = sizeof(hops);
+    if (setsockopt(fd, IPPROTO_IPV6, IPV6_MULTICAST_HOPS, &hops, len) != 0) {
+        jniThrowExceptionFmt(env, "java/net/SocketException",
+                "setsockopt(IPV6_MULTICAST_HOPS): %s", strerror(errno));
+        return;
+    }
+
+    // Set the unicast hoplimit to 255 (link-local only).
+    hops = kLinkLocalHopLimit;
+    len = sizeof(hops);
+    if (setsockopt(fd, IPPROTO_IPV6, IPV6_UNICAST_HOPS, &hops, len) != 0) {
+        jniThrowExceptionFmt(env, "java/net/SocketException",
+                "setsockopt(IPV6_UNICAST_HOPS): %s", strerror(errno));
+        return;
+    }
+
+    // Explicitly disable multicast loopback.
+    int off = 0;
+    len = sizeof(off);
+    if (setsockopt(fd, IPPROTO_IPV6, IPV6_MULTICAST_LOOP, &off, len) != 0) {
+        jniThrowExceptionFmt(env, "java/net/SocketException",
+                "setsockopt(IPV6_MULTICAST_LOOP): %s", strerror(errno));
+        return;
+    }
+
+    // Specify the IPv6 interface to use for outbound multicast.
+    len = sizeof(ifIndex);
+    if (setsockopt(fd, IPPROTO_IPV6, IPV6_MULTICAST_IF, &ifIndex, len) != 0) {
+        jniThrowExceptionFmt(env, "java/net/SocketException",
+                "setsockopt(IPV6_MULTICAST_IF): %s", strerror(errno));
+        return;
+    }
+
+    // Additional options to be considered:
+    //     - IPV6_TCLASS
+    //     - IPV6_RECVPKTINFO
+    //     - IPV6_RECVHOPLIMIT
+
+    // Bind to [::].
+    const struct sockaddr_in6 sin6 = {
+            .sin6_family = AF_INET6,
+            .sin6_port = 0,
+            .sin6_flowinfo = 0,
+            .sin6_addr = IN6ADDR_ANY_INIT,
+            .sin6_scope_id = 0,
+    };
+    auto sa = reinterpret_cast<const struct sockaddr *>(&sin6);
+    len = sizeof(sin6);
+    if (bind(fd, sa, len) != 0) {
+        jniThrowExceptionFmt(env, "java/net/SocketException",
+                "bind(IN6ADDR_ANY): %s", strerror(errno));
+        return;
+    }
+
+    // Join the all-routers multicast group, ff02::2%index.
+    struct ipv6_mreq all_rtrs = {
+        .ipv6mr_multiaddr = {{{0xff,2,0,0,0,0,0,0,0,0,0,0,0,0,0,2}}},
+        .ipv6mr_interface = ifIndex,
+    };
+    len = sizeof(all_rtrs);
+    if (setsockopt(fd, IPPROTO_IPV6, IPV6_JOIN_GROUP, &all_rtrs, len) != 0) {
+        jniThrowExceptionFmt(env, "java/net/SocketException",
+                "setsockopt(IPV6_JOIN_GROUP): %s", strerror(errno));
+        return;
+    }
+}
+
+/*
+ * JNI registration.
+ */
+static const JNINativeMethod gMethods[] = {
+    /* name, signature, funcPtr */
+    { "setupNaSocket", "(Ljava/io/FileDescriptor;)V",
+        (void*) android_net_util_setupNaSocket },
+    { "setupNsSocket", "(Ljava/io/FileDescriptor;)V",
+        (void*) android_net_util_setupNsSocket },
+    { "setupRaSocket", "(Ljava/io/FileDescriptor;I)V",
+        (void*) android_net_util_setupRaSocket },
+};
+
+int register_android_net_util_TetheringUtils(JNIEnv* env) {
+    return jniRegisterNativeMethods(env,
+            "android/net/util/TetheringUtils",
+            gMethods, NELEM(gMethods));
+}
+
+extern "C" jint JNI_OnLoad(JavaVM* vm, void*) {
+    JNIEnv *env;
+    if (vm->GetEnv(reinterpret_cast<void**>(&env), JNI_VERSION_1_6) != JNI_OK) {
+        __android_log_print(ANDROID_LOG_ERROR, LOG_TAG, "ERROR: GetEnv failed");
+        return JNI_ERR;
+    }
+
+    if (register_android_net_util_TetheringUtils(env) < 0) {
+        return JNI_ERR;
+    }
+
+    return JNI_VERSION_1_6;
+}
+
+}; // namespace android
diff --git a/Tethering/proguard.flags b/Tethering/proguard.flags
new file mode 100644
index 0000000..86b9033
--- /dev/null
+++ b/Tethering/proguard.flags
@@ -0,0 +1,9 @@
+# Keep class's integer static field for MessageUtils to parsing their name.
+-keep class com.android.networkstack.tethering.Tethering$TetherMainSM {
+    static final int CMD_*;
+    static final int EVENT_*;
+}
+
+-keepclassmembers class android.net.ip.IpServer {
+    static final int CMD_*;
+}
diff --git a/Tethering/res/drawable-hdpi/stat_sys_tether_bluetooth.png b/Tethering/res/drawable-hdpi/stat_sys_tether_bluetooth.png
new file mode 100644
index 0000000..9451174
--- /dev/null
+++ b/Tethering/res/drawable-hdpi/stat_sys_tether_bluetooth.png
Binary files differ
diff --git a/Tethering/res/drawable-hdpi/stat_sys_tether_general.png b/Tethering/res/drawable-hdpi/stat_sys_tether_general.png
new file mode 100644
index 0000000..79d5756
--- /dev/null
+++ b/Tethering/res/drawable-hdpi/stat_sys_tether_general.png
Binary files differ
diff --git a/Tethering/res/drawable-hdpi/stat_sys_tether_usb.png b/Tethering/res/drawable-hdpi/stat_sys_tether_usb.png
new file mode 100644
index 0000000..cae1bd1
--- /dev/null
+++ b/Tethering/res/drawable-hdpi/stat_sys_tether_usb.png
Binary files differ
diff --git a/Tethering/res/drawable-ldpi/stat_sys_tether_bluetooth.png b/Tethering/res/drawable-ldpi/stat_sys_tether_bluetooth.png
new file mode 100644
index 0000000..ffe8e8c
--- /dev/null
+++ b/Tethering/res/drawable-ldpi/stat_sys_tether_bluetooth.png
Binary files differ
diff --git a/Tethering/res/drawable-ldpi/stat_sys_tether_general.png b/Tethering/res/drawable-ldpi/stat_sys_tether_general.png
new file mode 100644
index 0000000..ca20f73
--- /dev/null
+++ b/Tethering/res/drawable-ldpi/stat_sys_tether_general.png
Binary files differ
diff --git a/Tethering/res/drawable-ldpi/stat_sys_tether_usb.png b/Tethering/res/drawable-ldpi/stat_sys_tether_usb.png
new file mode 100644
index 0000000..65e9075
--- /dev/null
+++ b/Tethering/res/drawable-ldpi/stat_sys_tether_usb.png
Binary files differ
diff --git a/Tethering/res/drawable-mdpi/stat_sys_tether_bluetooth.png b/Tethering/res/drawable-mdpi/stat_sys_tether_bluetooth.png
new file mode 100644
index 0000000..f42dae0
--- /dev/null
+++ b/Tethering/res/drawable-mdpi/stat_sys_tether_bluetooth.png
Binary files differ
diff --git a/Tethering/res/drawable-mdpi/stat_sys_tether_general.png b/Tethering/res/drawable-mdpi/stat_sys_tether_general.png
new file mode 100644
index 0000000..0655161
--- /dev/null
+++ b/Tethering/res/drawable-mdpi/stat_sys_tether_general.png
Binary files differ
diff --git a/Tethering/res/drawable-mdpi/stat_sys_tether_usb.png b/Tethering/res/drawable-mdpi/stat_sys_tether_usb.png
new file mode 100644
index 0000000..2e2b8ca
--- /dev/null
+++ b/Tethering/res/drawable-mdpi/stat_sys_tether_usb.png
Binary files differ
diff --git a/Tethering/res/drawable-xhdpi/stat_sys_tether_bluetooth.png b/Tethering/res/drawable-xhdpi/stat_sys_tether_bluetooth.png
new file mode 100644
index 0000000..3f57d1c
--- /dev/null
+++ b/Tethering/res/drawable-xhdpi/stat_sys_tether_bluetooth.png
Binary files differ
diff --git a/Tethering/res/drawable-xhdpi/stat_sys_tether_general.png b/Tethering/res/drawable-xhdpi/stat_sys_tether_general.png
new file mode 100644
index 0000000..34b0cb3
--- /dev/null
+++ b/Tethering/res/drawable-xhdpi/stat_sys_tether_general.png
Binary files differ
diff --git a/Tethering/res/drawable-xhdpi/stat_sys_tether_usb.png b/Tethering/res/drawable-xhdpi/stat_sys_tether_usb.png
new file mode 100644
index 0000000..36afe48
--- /dev/null
+++ b/Tethering/res/drawable-xhdpi/stat_sys_tether_usb.png
Binary files differ
diff --git a/Tethering/res/drawable-xxhdpi/stat_sys_tether_bluetooth.png b/Tethering/res/drawable-xxhdpi/stat_sys_tether_bluetooth.png
new file mode 100644
index 0000000..25acfbb
--- /dev/null
+++ b/Tethering/res/drawable-xxhdpi/stat_sys_tether_bluetooth.png
Binary files differ
diff --git a/Tethering/res/drawable-xxhdpi/stat_sys_tether_general.png b/Tethering/res/drawable-xxhdpi/stat_sys_tether_general.png
new file mode 100644
index 0000000..5c65601
--- /dev/null
+++ b/Tethering/res/drawable-xxhdpi/stat_sys_tether_general.png
Binary files differ
diff --git a/Tethering/res/drawable-xxhdpi/stat_sys_tether_usb.png b/Tethering/res/drawable-xxhdpi/stat_sys_tether_usb.png
new file mode 100644
index 0000000..28b4b54
--- /dev/null
+++ b/Tethering/res/drawable-xxhdpi/stat_sys_tether_usb.png
Binary files differ
diff --git a/Tethering/res/values-af/strings.xml b/Tethering/res/values-af/strings.xml
new file mode 100644
index 0000000..056168b
--- /dev/null
+++ b/Tethering/res/values-af/strings.xml
@@ -0,0 +1,29 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!--  Copyright (C) 2020 The Android Open Source Project
+
+     Licensed under the Apache License, Version 2.0 (the "License");
+     you may not use this file except in compliance with the License.
+     You may obtain a copy of the License at
+
+          http://www.apache.org/licenses/LICENSE-2.0
+
+     Unless required by applicable law or agreed to in writing, software
+     distributed under the License is distributed on an "AS IS" BASIS,
+     WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+     See the License for the specific language governing permissions and
+     limitations under the License.
+ -->
+
+<resources xmlns:android="http://schemas.android.com/apk/res/android"
+    xmlns:xliff="urn:oasis:names:tc:xliff:document:1.2">
+    <string name="tethered_notification_title" msgid="6426563586025792944">"Verbinding of warmkol is aktief"</string>
+    <string name="tethered_notification_message" msgid="64800879503420696">"Tik om op te stel."</string>
+    <string name="disable_tether_notification_title" msgid="3004509127903564191">"Verbinding is gedeaktiveer"</string>
+    <string name="disable_tether_notification_message" msgid="6717523799293901476">"Kontak jou administrateur vir besonderhede"</string>
+    <string name="notification_channel_tethering_status" msgid="2663463891530932727">"Warmkol- en verbindingstatus"</string>
+    <string name="no_upstream_notification_title" msgid="1204601824631788482"></string>
+    <string name="no_upstream_notification_message" msgid="8586582938243032621"></string>
+    <string name="no_upstream_notification_disable_button" msgid="8800919436924640822"></string>
+    <string name="upstream_roaming_notification_title" msgid="4772373823198997030"></string>
+    <string name="upstream_roaming_notification_message" msgid="3985577843181551650"></string>
+</resources>
diff --git a/Tethering/res/values-am/strings.xml b/Tethering/res/values-am/strings.xml
new file mode 100644
index 0000000..ac468dd
--- /dev/null
+++ b/Tethering/res/values-am/strings.xml
@@ -0,0 +1,29 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!--  Copyright (C) 2020 The Android Open Source Project
+
+     Licensed under the Apache License, Version 2.0 (the "License");
+     you may not use this file except in compliance with the License.
+     You may obtain a copy of the License at
+
+          http://www.apache.org/licenses/LICENSE-2.0
+
+     Unless required by applicable law or agreed to in writing, software
+     distributed under the License is distributed on an "AS IS" BASIS,
+     WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+     See the License for the specific language governing permissions and
+     limitations under the License.
+ -->
+
+<resources xmlns:android="http://schemas.android.com/apk/res/android"
+    xmlns:xliff="urn:oasis:names:tc:xliff:document:1.2">
+    <string name="tethered_notification_title" msgid="6426563586025792944">"እንደ ሞደም መሰካት ወይም መገናኛ ነጥብ ገባሪ"</string>
+    <string name="tethered_notification_message" msgid="64800879503420696">"ለማዋቀር መታ ያድርጉ።"</string>
+    <string name="disable_tether_notification_title" msgid="3004509127903564191">"እንደ ሞደም መሰካት ተሰናክሏል"</string>
+    <string name="disable_tether_notification_message" msgid="6717523799293901476">"ለዝርዝሮች የእርስዎን አስተዳዳሪ ያነጋግሩ"</string>
+    <string name="notification_channel_tethering_status" msgid="2663463891530932727">"መገናኛ ነጥብ እና እንደ ሞደም የመሰካት ሁኔታ"</string>
+    <string name="no_upstream_notification_title" msgid="1204601824631788482"></string>
+    <string name="no_upstream_notification_message" msgid="8586582938243032621"></string>
+    <string name="no_upstream_notification_disable_button" msgid="8800919436924640822"></string>
+    <string name="upstream_roaming_notification_title" msgid="4772373823198997030"></string>
+    <string name="upstream_roaming_notification_message" msgid="3985577843181551650"></string>
+</resources>
diff --git a/Tethering/res/values-ar/strings.xml b/Tethering/res/values-ar/strings.xml
new file mode 100644
index 0000000..7d5bad3
--- /dev/null
+++ b/Tethering/res/values-ar/strings.xml
@@ -0,0 +1,29 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!--  Copyright (C) 2020 The Android Open Source Project
+
+     Licensed under the Apache License, Version 2.0 (the "License");
+     you may not use this file except in compliance with the License.
+     You may obtain a copy of the License at
+
+          http://www.apache.org/licenses/LICENSE-2.0
+
+     Unless required by applicable law or agreed to in writing, software
+     distributed under the License is distributed on an "AS IS" BASIS,
+     WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+     See the License for the specific language governing permissions and
+     limitations under the License.
+ -->
+
+<resources xmlns:android="http://schemas.android.com/apk/res/android"
+    xmlns:xliff="urn:oasis:names:tc:xliff:document:1.2">
+    <string name="tethered_notification_title" msgid="6426563586025792944">"النطاق نشط أو نقطة الاتصال نشطة"</string>
+    <string name="tethered_notification_message" msgid="64800879503420696">"انقر للإعداد."</string>
+    <string name="disable_tether_notification_title" msgid="3004509127903564191">"التوصيل متوقف."</string>
+    <string name="disable_tether_notification_message" msgid="6717523799293901476">"تواصَل مع المشرف للحصول على التفاصيل."</string>
+    <string name="notification_channel_tethering_status" msgid="2663463891530932727">"حالة نقطة الاتصال والتوصيل"</string>
+    <string name="no_upstream_notification_title" msgid="1204601824631788482"></string>
+    <string name="no_upstream_notification_message" msgid="8586582938243032621"></string>
+    <string name="no_upstream_notification_disable_button" msgid="8800919436924640822"></string>
+    <string name="upstream_roaming_notification_title" msgid="4772373823198997030"></string>
+    <string name="upstream_roaming_notification_message" msgid="3985577843181551650"></string>
+</resources>
diff --git a/Tethering/res/values-as/strings.xml b/Tethering/res/values-as/strings.xml
new file mode 100644
index 0000000..0913504
--- /dev/null
+++ b/Tethering/res/values-as/strings.xml
@@ -0,0 +1,29 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!--  Copyright (C) 2020 The Android Open Source Project
+
+     Licensed under the Apache License, Version 2.0 (the "License");
+     you may not use this file except in compliance with the License.
+     You may obtain a copy of the License at
+
+          http://www.apache.org/licenses/LICENSE-2.0
+
+     Unless required by applicable law or agreed to in writing, software
+     distributed under the License is distributed on an "AS IS" BASIS,
+     WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+     See the License for the specific language governing permissions and
+     limitations under the License.
+ -->
+
+<resources xmlns:android="http://schemas.android.com/apk/res/android"
+    xmlns:xliff="urn:oasis:names:tc:xliff:document:1.2">
+    <string name="tethered_notification_title" msgid="6426563586025792944">"টে\'ডাৰিং অথবা হ\'টস্প\'ট সক্ৰিয় অৱস্থাত আছে"</string>
+    <string name="tethered_notification_message" msgid="64800879503420696">"ছেট আপ কৰিবলৈ টিপক।"</string>
+    <string name="disable_tether_notification_title" msgid="3004509127903564191">"টে\'ডাৰিঙৰ সুবিধাটো অক্ষম কৰি থোৱা হৈছে"</string>
+    <string name="disable_tether_notification_message" msgid="6717523799293901476">"সবিশেষ জানিবলৈ আপোনাৰ প্ৰশাসকৰ সৈতে যোগাযোগ কৰক"</string>
+    <string name="notification_channel_tethering_status" msgid="2663463891530932727">"হ’টস্প\'ট আৰু টে\'ডাৰিঙৰ স্থিতি"</string>
+    <string name="no_upstream_notification_title" msgid="1204601824631788482"></string>
+    <string name="no_upstream_notification_message" msgid="8586582938243032621"></string>
+    <string name="no_upstream_notification_disable_button" msgid="8800919436924640822"></string>
+    <string name="upstream_roaming_notification_title" msgid="4772373823198997030"></string>
+    <string name="upstream_roaming_notification_message" msgid="3985577843181551650"></string>
+</resources>
diff --git a/Tethering/res/values-az/strings.xml b/Tethering/res/values-az/strings.xml
new file mode 100644
index 0000000..dce70da
--- /dev/null
+++ b/Tethering/res/values-az/strings.xml
@@ -0,0 +1,29 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!--  Copyright (C) 2020 The Android Open Source Project
+
+     Licensed under the Apache License, Version 2.0 (the "License");
+     you may not use this file except in compliance with the License.
+     You may obtain a copy of the License at
+
+          http://www.apache.org/licenses/LICENSE-2.0
+
+     Unless required by applicable law or agreed to in writing, software
+     distributed under the License is distributed on an "AS IS" BASIS,
+     WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+     See the License for the specific language governing permissions and
+     limitations under the License.
+ -->
+
+<resources xmlns:android="http://schemas.android.com/apk/res/android"
+    xmlns:xliff="urn:oasis:names:tc:xliff:document:1.2">
+    <string name="tethered_notification_title" msgid="6426563586025792944">"Birləşmə və ya hotspot aktivdir"</string>
+    <string name="tethered_notification_message" msgid="64800879503420696">"Ayarlamaq üçün toxunun."</string>
+    <string name="disable_tether_notification_title" msgid="3004509127903564191">"Birləşmə deaktivdir"</string>
+    <string name="disable_tether_notification_message" msgid="6717523799293901476">"Detallar üçün adminlə əlaqə saxlayın"</string>
+    <string name="notification_channel_tethering_status" msgid="2663463891530932727">"Hotspot &amp; birləşmə statusu"</string>
+    <string name="no_upstream_notification_title" msgid="1204601824631788482"></string>
+    <string name="no_upstream_notification_message" msgid="8586582938243032621"></string>
+    <string name="no_upstream_notification_disable_button" msgid="8800919436924640822"></string>
+    <string name="upstream_roaming_notification_title" msgid="4772373823198997030"></string>
+    <string name="upstream_roaming_notification_message" msgid="3985577843181551650"></string>
+</resources>
diff --git a/Tethering/res/values-b+sr+Latn/strings.xml b/Tethering/res/values-b+sr+Latn/strings.xml
new file mode 100644
index 0000000..b0774ec
--- /dev/null
+++ b/Tethering/res/values-b+sr+Latn/strings.xml
@@ -0,0 +1,29 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!--  Copyright (C) 2020 The Android Open Source Project
+
+     Licensed under the Apache License, Version 2.0 (the "License");
+     you may not use this file except in compliance with the License.
+     You may obtain a copy of the License at
+
+          http://www.apache.org/licenses/LICENSE-2.0
+
+     Unless required by applicable law or agreed to in writing, software
+     distributed under the License is distributed on an "AS IS" BASIS,
+     WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+     See the License for the specific language governing permissions and
+     limitations under the License.
+ -->
+
+<resources xmlns:android="http://schemas.android.com/apk/res/android"
+    xmlns:xliff="urn:oasis:names:tc:xliff:document:1.2">
+    <string name="tethered_notification_title" msgid="6426563586025792944">"Privezivanje ili hotspot je aktivan"</string>
+    <string name="tethered_notification_message" msgid="64800879503420696">"Dodirnite da biste podesili."</string>
+    <string name="disable_tether_notification_title" msgid="3004509127903564191">"Privezivanje je onemogućeno"</string>
+    <string name="disable_tether_notification_message" msgid="6717523799293901476">"Potražite detalje od administratora"</string>
+    <string name="notification_channel_tethering_status" msgid="2663463891530932727">"Status hotspota i privezivanja"</string>
+    <string name="no_upstream_notification_title" msgid="1204601824631788482"></string>
+    <string name="no_upstream_notification_message" msgid="8586582938243032621"></string>
+    <string name="no_upstream_notification_disable_button" msgid="8800919436924640822"></string>
+    <string name="upstream_roaming_notification_title" msgid="4772373823198997030"></string>
+    <string name="upstream_roaming_notification_message" msgid="3985577843181551650"></string>
+</resources>
diff --git a/Tethering/res/values-be/strings.xml b/Tethering/res/values-be/strings.xml
new file mode 100644
index 0000000..a8acebe
--- /dev/null
+++ b/Tethering/res/values-be/strings.xml
@@ -0,0 +1,29 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!--  Copyright (C) 2020 The Android Open Source Project
+
+     Licensed under the Apache License, Version 2.0 (the "License");
+     you may not use this file except in compliance with the License.
+     You may obtain a copy of the License at
+
+          http://www.apache.org/licenses/LICENSE-2.0
+
+     Unless required by applicable law or agreed to in writing, software
+     distributed under the License is distributed on an "AS IS" BASIS,
+     WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+     See the License for the specific language governing permissions and
+     limitations under the License.
+ -->
+
+<resources xmlns:android="http://schemas.android.com/apk/res/android"
+    xmlns:xliff="urn:oasis:names:tc:xliff:document:1.2">
+    <string name="tethered_notification_title" msgid="6426563586025792944">"Мадэм або хот-спот актыўныя"</string>
+    <string name="tethered_notification_message" msgid="64800879503420696">"Дакраніцеся, каб наладзіць."</string>
+    <string name="disable_tether_notification_title" msgid="3004509127903564191">"Рэжым мадэма выключаны"</string>
+    <string name="disable_tether_notification_message" msgid="6717523799293901476">"Звярніцеся да адміністратара па падрабязную інфармацыю"</string>
+    <string name="notification_channel_tethering_status" msgid="2663463891530932727">"Стан \"Хот-спот і мадэм\""</string>
+    <string name="no_upstream_notification_title" msgid="1204601824631788482"></string>
+    <string name="no_upstream_notification_message" msgid="8586582938243032621"></string>
+    <string name="no_upstream_notification_disable_button" msgid="8800919436924640822"></string>
+    <string name="upstream_roaming_notification_title" msgid="4772373823198997030"></string>
+    <string name="upstream_roaming_notification_message" msgid="3985577843181551650"></string>
+</resources>
diff --git a/Tethering/res/values-bg/strings.xml b/Tethering/res/values-bg/strings.xml
new file mode 100644
index 0000000..94fb2d8
--- /dev/null
+++ b/Tethering/res/values-bg/strings.xml
@@ -0,0 +1,29 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!--  Copyright (C) 2020 The Android Open Source Project
+
+     Licensed under the Apache License, Version 2.0 (the "License");
+     you may not use this file except in compliance with the License.
+     You may obtain a copy of the License at
+
+          http://www.apache.org/licenses/LICENSE-2.0
+
+     Unless required by applicable law or agreed to in writing, software
+     distributed under the License is distributed on an "AS IS" BASIS,
+     WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+     See the License for the specific language governing permissions and
+     limitations under the License.
+ -->
+
+<resources xmlns:android="http://schemas.android.com/apk/res/android"
+    xmlns:xliff="urn:oasis:names:tc:xliff:document:1.2">
+    <string name="tethered_notification_title" msgid="6426563586025792944">"Има активна споделена връзка или точка за достъп"</string>
+    <string name="tethered_notification_message" msgid="64800879503420696">"Докоснете, за да настроите."</string>
+    <string name="disable_tether_notification_title" msgid="3004509127903564191">"Функцията за тетъринг е деактивирана"</string>
+    <string name="disable_tether_notification_message" msgid="6717523799293901476">"Свържете се с администратора си за подробности"</string>
+    <string name="notification_channel_tethering_status" msgid="2663463891530932727">"Състояние на функцията за точка за достъп и тетъринг"</string>
+    <string name="no_upstream_notification_title" msgid="1204601824631788482"></string>
+    <string name="no_upstream_notification_message" msgid="8586582938243032621"></string>
+    <string name="no_upstream_notification_disable_button" msgid="8800919436924640822"></string>
+    <string name="upstream_roaming_notification_title" msgid="4772373823198997030"></string>
+    <string name="upstream_roaming_notification_message" msgid="3985577843181551650"></string>
+</resources>
diff --git a/Tethering/res/values-bn/strings.xml b/Tethering/res/values-bn/strings.xml
new file mode 100644
index 0000000..aea02b9
--- /dev/null
+++ b/Tethering/res/values-bn/strings.xml
@@ -0,0 +1,29 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!--  Copyright (C) 2020 The Android Open Source Project
+
+     Licensed under the Apache License, Version 2.0 (the "License");
+     you may not use this file except in compliance with the License.
+     You may obtain a copy of the License at
+
+          http://www.apache.org/licenses/LICENSE-2.0
+
+     Unless required by applicable law or agreed to in writing, software
+     distributed under the License is distributed on an "AS IS" BASIS,
+     WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+     See the License for the specific language governing permissions and
+     limitations under the License.
+ -->
+
+<resources xmlns:android="http://schemas.android.com/apk/res/android"
+    xmlns:xliff="urn:oasis:names:tc:xliff:document:1.2">
+    <string name="tethered_notification_title" msgid="6426563586025792944">"টিথারিং বা হটস্পট চালু আছে"</string>
+    <string name="tethered_notification_message" msgid="64800879503420696">"সেট-আপ করতে ট্যাপ করুন।"</string>
+    <string name="disable_tether_notification_title" msgid="3004509127903564191">"টিথারিং বন্ধ করা আছে"</string>
+    <string name="disable_tether_notification_message" msgid="6717523799293901476">"বিশদে জানতে অ্যাডমিনের সাথে যোগাযোগ করুন"</string>
+    <string name="notification_channel_tethering_status" msgid="2663463891530932727">"হটস্পট ও টিথারিং স্ট্যাটাস"</string>
+    <string name="no_upstream_notification_title" msgid="1204601824631788482"></string>
+    <string name="no_upstream_notification_message" msgid="8586582938243032621"></string>
+    <string name="no_upstream_notification_disable_button" msgid="8800919436924640822"></string>
+    <string name="upstream_roaming_notification_title" msgid="4772373823198997030"></string>
+    <string name="upstream_roaming_notification_message" msgid="3985577843181551650"></string>
+</resources>
diff --git a/Tethering/res/values-bs/strings.xml b/Tethering/res/values-bs/strings.xml
new file mode 100644
index 0000000..de23272
--- /dev/null
+++ b/Tethering/res/values-bs/strings.xml
@@ -0,0 +1,29 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!--  Copyright (C) 2020 The Android Open Source Project
+
+     Licensed under the Apache License, Version 2.0 (the "License");
+     you may not use this file except in compliance with the License.
+     You may obtain a copy of the License at
+
+          http://www.apache.org/licenses/LICENSE-2.0
+
+     Unless required by applicable law or agreed to in writing, software
+     distributed under the License is distributed on an "AS IS" BASIS,
+     WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+     See the License for the specific language governing permissions and
+     limitations under the License.
+ -->
+
+<resources xmlns:android="http://schemas.android.com/apk/res/android"
+    xmlns:xliff="urn:oasis:names:tc:xliff:document:1.2">
+    <string name="tethered_notification_title" msgid="6426563586025792944">"Aktivno je povezivanje putem mobitela ili pristupna tačka"</string>
+    <string name="tethered_notification_message" msgid="64800879503420696">"Dodirnite da postavite."</string>
+    <string name="disable_tether_notification_title" msgid="3004509127903564191">"Povezivanje putem mobitela je onemogućeno"</string>
+    <string name="disable_tether_notification_message" msgid="6717523799293901476">"Kontaktirajte svog administratora za detalje"</string>
+    <string name="notification_channel_tethering_status" msgid="2663463891530932727">"Status pristupne tačke i povezivanja putem mobitela"</string>
+    <string name="no_upstream_notification_title" msgid="1204601824631788482"></string>
+    <string name="no_upstream_notification_message" msgid="8586582938243032621"></string>
+    <string name="no_upstream_notification_disable_button" msgid="8800919436924640822"></string>
+    <string name="upstream_roaming_notification_title" msgid="4772373823198997030"></string>
+    <string name="upstream_roaming_notification_message" msgid="3985577843181551650"></string>
+</resources>
diff --git a/Tethering/res/values-ca/strings.xml b/Tethering/res/values-ca/strings.xml
new file mode 100644
index 0000000..88b795c
--- /dev/null
+++ b/Tethering/res/values-ca/strings.xml
@@ -0,0 +1,29 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!--  Copyright (C) 2020 The Android Open Source Project
+
+     Licensed under the Apache License, Version 2.0 (the "License");
+     you may not use this file except in compliance with the License.
+     You may obtain a copy of the License at
+
+          http://www.apache.org/licenses/LICENSE-2.0
+
+     Unless required by applicable law or agreed to in writing, software
+     distributed under the License is distributed on an "AS IS" BASIS,
+     WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+     See the License for the specific language governing permissions and
+     limitations under the License.
+ -->
+
+<resources xmlns:android="http://schemas.android.com/apk/res/android"
+    xmlns:xliff="urn:oasis:names:tc:xliff:document:1.2">
+    <string name="tethered_notification_title" msgid="6426563586025792944">"Compartició de xarxa o punt d\'accés Wi‑Fi actius"</string>
+    <string name="tethered_notification_message" msgid="64800879503420696">"Toca per configurar."</string>
+    <string name="disable_tether_notification_title" msgid="3004509127903564191">"La compartició de xarxa està desactivada"</string>
+    <string name="disable_tether_notification_message" msgid="6717523799293901476">"Contacta amb el teu administrador per obtenir més informació"</string>
+    <string name="notification_channel_tethering_status" msgid="2663463891530932727">"Estat del punt d\'accés Wi‑Fi i de la compartició de xarxa"</string>
+    <string name="no_upstream_notification_title" msgid="1204601824631788482"></string>
+    <string name="no_upstream_notification_message" msgid="8586582938243032621"></string>
+    <string name="no_upstream_notification_disable_button" msgid="8800919436924640822"></string>
+    <string name="upstream_roaming_notification_title" msgid="4772373823198997030"></string>
+    <string name="upstream_roaming_notification_message" msgid="3985577843181551650"></string>
+</resources>
diff --git a/Tethering/res/values-cs/strings.xml b/Tethering/res/values-cs/strings.xml
new file mode 100644
index 0000000..8c1b83b
--- /dev/null
+++ b/Tethering/res/values-cs/strings.xml
@@ -0,0 +1,29 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!--  Copyright (C) 2020 The Android Open Source Project
+
+     Licensed under the Apache License, Version 2.0 (the "License");
+     you may not use this file except in compliance with the License.
+     You may obtain a copy of the License at
+
+          http://www.apache.org/licenses/LICENSE-2.0
+
+     Unless required by applicable law or agreed to in writing, software
+     distributed under the License is distributed on an "AS IS" BASIS,
+     WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+     See the License for the specific language governing permissions and
+     limitations under the License.
+ -->
+
+<resources xmlns:android="http://schemas.android.com/apk/res/android"
+    xmlns:xliff="urn:oasis:names:tc:xliff:document:1.2">
+    <string name="tethered_notification_title" msgid="6426563586025792944">"Tethering nebo hotspot je aktivní"</string>
+    <string name="tethered_notification_message" msgid="64800879503420696">"Klepnutím zahájíte nastavení."</string>
+    <string name="disable_tether_notification_title" msgid="3004509127903564191">"Tethering je zakázán"</string>
+    <string name="disable_tether_notification_message" msgid="6717523799293901476">"O podrobnosti požádejte administrátora"</string>
+    <string name="notification_channel_tethering_status" msgid="2663463891530932727">"Stav hotspotu a tetheringu"</string>
+    <string name="no_upstream_notification_title" msgid="1204601824631788482"></string>
+    <string name="no_upstream_notification_message" msgid="8586582938243032621"></string>
+    <string name="no_upstream_notification_disable_button" msgid="8800919436924640822"></string>
+    <string name="upstream_roaming_notification_title" msgid="4772373823198997030"></string>
+    <string name="upstream_roaming_notification_message" msgid="3985577843181551650"></string>
+</resources>
diff --git a/Tethering/res/values-da/strings.xml b/Tethering/res/values-da/strings.xml
new file mode 100644
index 0000000..f413e70
--- /dev/null
+++ b/Tethering/res/values-da/strings.xml
@@ -0,0 +1,29 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!--  Copyright (C) 2020 The Android Open Source Project
+
+     Licensed under the Apache License, Version 2.0 (the "License");
+     you may not use this file except in compliance with the License.
+     You may obtain a copy of the License at
+
+          http://www.apache.org/licenses/LICENSE-2.0
+
+     Unless required by applicable law or agreed to in writing, software
+     distributed under the License is distributed on an "AS IS" BASIS,
+     WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+     See the License for the specific language governing permissions and
+     limitations under the License.
+ -->
+
+<resources xmlns:android="http://schemas.android.com/apk/res/android"
+    xmlns:xliff="urn:oasis:names:tc:xliff:document:1.2">
+    <string name="tethered_notification_title" msgid="6426563586025792944">"Netdeling eller hotspot er aktivt"</string>
+    <string name="tethered_notification_message" msgid="64800879503420696">"Tryk for at konfigurere."</string>
+    <string name="disable_tether_notification_title" msgid="3004509127903564191">"Netdeling er deaktiveret"</string>
+    <string name="disable_tether_notification_message" msgid="6717523799293901476">"Kontakt din administrator for at få oplysninger"</string>
+    <string name="notification_channel_tethering_status" msgid="2663463891530932727">"Status for hotspot og netdeling"</string>
+    <string name="no_upstream_notification_title" msgid="1204601824631788482"></string>
+    <string name="no_upstream_notification_message" msgid="8586582938243032621"></string>
+    <string name="no_upstream_notification_disable_button" msgid="8800919436924640822"></string>
+    <string name="upstream_roaming_notification_title" msgid="4772373823198997030"></string>
+    <string name="upstream_roaming_notification_message" msgid="3985577843181551650"></string>
+</resources>
diff --git a/Tethering/res/values-de/strings.xml b/Tethering/res/values-de/strings.xml
new file mode 100644
index 0000000..f057d78
--- /dev/null
+++ b/Tethering/res/values-de/strings.xml
@@ -0,0 +1,29 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!--  Copyright (C) 2020 The Android Open Source Project
+
+     Licensed under the Apache License, Version 2.0 (the "License");
+     you may not use this file except in compliance with the License.
+     You may obtain a copy of the License at
+
+          http://www.apache.org/licenses/LICENSE-2.0
+
+     Unless required by applicable law or agreed to in writing, software
+     distributed under the License is distributed on an "AS IS" BASIS,
+     WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+     See the License for the specific language governing permissions and
+     limitations under the License.
+ -->
+
+<resources xmlns:android="http://schemas.android.com/apk/res/android"
+    xmlns:xliff="urn:oasis:names:tc:xliff:document:1.2">
+    <string name="tethered_notification_title" msgid="6426563586025792944">"Tethering oder Hotspot aktiv"</string>
+    <string name="tethered_notification_message" msgid="64800879503420696">"Zum Einrichten tippen."</string>
+    <string name="disable_tether_notification_title" msgid="3004509127903564191">"Tethering ist deaktiviert"</string>
+    <string name="disable_tether_notification_message" msgid="6717523799293901476">"Bitte wende dich für weitere Informationen an den Administrator"</string>
+    <string name="notification_channel_tethering_status" msgid="2663463891530932727">"Hotspot- und Tethering-Status"</string>
+    <string name="no_upstream_notification_title" msgid="1204601824631788482"></string>
+    <string name="no_upstream_notification_message" msgid="8586582938243032621"></string>
+    <string name="no_upstream_notification_disable_button" msgid="8800919436924640822"></string>
+    <string name="upstream_roaming_notification_title" msgid="4772373823198997030"></string>
+    <string name="upstream_roaming_notification_message" msgid="3985577843181551650"></string>
+</resources>
diff --git a/Tethering/res/values-el/strings.xml b/Tethering/res/values-el/strings.xml
new file mode 100644
index 0000000..b3c986b
--- /dev/null
+++ b/Tethering/res/values-el/strings.xml
@@ -0,0 +1,29 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!--  Copyright (C) 2020 The Android Open Source Project
+
+     Licensed under the Apache License, Version 2.0 (the "License");
+     you may not use this file except in compliance with the License.
+     You may obtain a copy of the License at
+
+          http://www.apache.org/licenses/LICENSE-2.0
+
+     Unless required by applicable law or agreed to in writing, software
+     distributed under the License is distributed on an "AS IS" BASIS,
+     WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+     See the License for the specific language governing permissions and
+     limitations under the License.
+ -->
+
+<resources xmlns:android="http://schemas.android.com/apk/res/android"
+    xmlns:xliff="urn:oasis:names:tc:xliff:document:1.2">
+    <string name="tethered_notification_title" msgid="6426563586025792944">"Πρόσδεση ή σύνδεση σημείου πρόσβασης ενεργή"</string>
+    <string name="tethered_notification_message" msgid="64800879503420696">"Πατήστε για ρύθμιση."</string>
+    <string name="disable_tether_notification_title" msgid="3004509127903564191">"Η σύνδεση είναι απενεργοποιημένη"</string>
+    <string name="disable_tether_notification_message" msgid="6717523799293901476">"Επικοινωνήστε με τον διαχειριστή σας για λεπτομέρειες"</string>
+    <string name="notification_channel_tethering_status" msgid="2663463891530932727">"Κατάσταση σημείου πρόσβασης Wi-Fi και σύνδεσης"</string>
+    <string name="no_upstream_notification_title" msgid="1204601824631788482"></string>
+    <string name="no_upstream_notification_message" msgid="8586582938243032621"></string>
+    <string name="no_upstream_notification_disable_button" msgid="8800919436924640822"></string>
+    <string name="upstream_roaming_notification_title" msgid="4772373823198997030"></string>
+    <string name="upstream_roaming_notification_message" msgid="3985577843181551650"></string>
+</resources>
diff --git a/Tethering/res/values-en-rAU/strings.xml b/Tethering/res/values-en-rAU/strings.xml
new file mode 100644
index 0000000..769e012
--- /dev/null
+++ b/Tethering/res/values-en-rAU/strings.xml
@@ -0,0 +1,29 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!--  Copyright (C) 2020 The Android Open Source Project
+
+     Licensed under the Apache License, Version 2.0 (the "License");
+     you may not use this file except in compliance with the License.
+     You may obtain a copy of the License at
+
+          http://www.apache.org/licenses/LICENSE-2.0
+
+     Unless required by applicable law or agreed to in writing, software
+     distributed under the License is distributed on an "AS IS" BASIS,
+     WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+     See the License for the specific language governing permissions and
+     limitations under the License.
+ -->
+
+<resources xmlns:android="http://schemas.android.com/apk/res/android"
+    xmlns:xliff="urn:oasis:names:tc:xliff:document:1.2">
+    <string name="tethered_notification_title" msgid="6426563586025792944">"Tethering or hotspot active"</string>
+    <string name="tethered_notification_message" msgid="64800879503420696">"Tap to set up."</string>
+    <string name="disable_tether_notification_title" msgid="3004509127903564191">"Tethering is disabled"</string>
+    <string name="disable_tether_notification_message" msgid="6717523799293901476">"Contact your admin for details"</string>
+    <string name="notification_channel_tethering_status" msgid="2663463891530932727">"Hotspot and tethering status"</string>
+    <string name="no_upstream_notification_title" msgid="1204601824631788482"></string>
+    <string name="no_upstream_notification_message" msgid="8586582938243032621"></string>
+    <string name="no_upstream_notification_disable_button" msgid="8800919436924640822"></string>
+    <string name="upstream_roaming_notification_title" msgid="4772373823198997030"></string>
+    <string name="upstream_roaming_notification_message" msgid="3985577843181551650"></string>
+</resources>
diff --git a/Tethering/res/values-en-rCA/strings.xml b/Tethering/res/values-en-rCA/strings.xml
new file mode 100644
index 0000000..769e012
--- /dev/null
+++ b/Tethering/res/values-en-rCA/strings.xml
@@ -0,0 +1,29 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!--  Copyright (C) 2020 The Android Open Source Project
+
+     Licensed under the Apache License, Version 2.0 (the "License");
+     you may not use this file except in compliance with the License.
+     You may obtain a copy of the License at
+
+          http://www.apache.org/licenses/LICENSE-2.0
+
+     Unless required by applicable law or agreed to in writing, software
+     distributed under the License is distributed on an "AS IS" BASIS,
+     WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+     See the License for the specific language governing permissions and
+     limitations under the License.
+ -->
+
+<resources xmlns:android="http://schemas.android.com/apk/res/android"
+    xmlns:xliff="urn:oasis:names:tc:xliff:document:1.2">
+    <string name="tethered_notification_title" msgid="6426563586025792944">"Tethering or hotspot active"</string>
+    <string name="tethered_notification_message" msgid="64800879503420696">"Tap to set up."</string>
+    <string name="disable_tether_notification_title" msgid="3004509127903564191">"Tethering is disabled"</string>
+    <string name="disable_tether_notification_message" msgid="6717523799293901476">"Contact your admin for details"</string>
+    <string name="notification_channel_tethering_status" msgid="2663463891530932727">"Hotspot and tethering status"</string>
+    <string name="no_upstream_notification_title" msgid="1204601824631788482"></string>
+    <string name="no_upstream_notification_message" msgid="8586582938243032621"></string>
+    <string name="no_upstream_notification_disable_button" msgid="8800919436924640822"></string>
+    <string name="upstream_roaming_notification_title" msgid="4772373823198997030"></string>
+    <string name="upstream_roaming_notification_message" msgid="3985577843181551650"></string>
+</resources>
diff --git a/Tethering/res/values-en-rGB/strings.xml b/Tethering/res/values-en-rGB/strings.xml
new file mode 100644
index 0000000..769e012
--- /dev/null
+++ b/Tethering/res/values-en-rGB/strings.xml
@@ -0,0 +1,29 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!--  Copyright (C) 2020 The Android Open Source Project
+
+     Licensed under the Apache License, Version 2.0 (the "License");
+     you may not use this file except in compliance with the License.
+     You may obtain a copy of the License at
+
+          http://www.apache.org/licenses/LICENSE-2.0
+
+     Unless required by applicable law or agreed to in writing, software
+     distributed under the License is distributed on an "AS IS" BASIS,
+     WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+     See the License for the specific language governing permissions and
+     limitations under the License.
+ -->
+
+<resources xmlns:android="http://schemas.android.com/apk/res/android"
+    xmlns:xliff="urn:oasis:names:tc:xliff:document:1.2">
+    <string name="tethered_notification_title" msgid="6426563586025792944">"Tethering or hotspot active"</string>
+    <string name="tethered_notification_message" msgid="64800879503420696">"Tap to set up."</string>
+    <string name="disable_tether_notification_title" msgid="3004509127903564191">"Tethering is disabled"</string>
+    <string name="disable_tether_notification_message" msgid="6717523799293901476">"Contact your admin for details"</string>
+    <string name="notification_channel_tethering_status" msgid="2663463891530932727">"Hotspot and tethering status"</string>
+    <string name="no_upstream_notification_title" msgid="1204601824631788482"></string>
+    <string name="no_upstream_notification_message" msgid="8586582938243032621"></string>
+    <string name="no_upstream_notification_disable_button" msgid="8800919436924640822"></string>
+    <string name="upstream_roaming_notification_title" msgid="4772373823198997030"></string>
+    <string name="upstream_roaming_notification_message" msgid="3985577843181551650"></string>
+</resources>
diff --git a/Tethering/res/values-en-rIN/strings.xml b/Tethering/res/values-en-rIN/strings.xml
new file mode 100644
index 0000000..769e012
--- /dev/null
+++ b/Tethering/res/values-en-rIN/strings.xml
@@ -0,0 +1,29 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!--  Copyright (C) 2020 The Android Open Source Project
+
+     Licensed under the Apache License, Version 2.0 (the "License");
+     you may not use this file except in compliance with the License.
+     You may obtain a copy of the License at
+
+          http://www.apache.org/licenses/LICENSE-2.0
+
+     Unless required by applicable law or agreed to in writing, software
+     distributed under the License is distributed on an "AS IS" BASIS,
+     WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+     See the License for the specific language governing permissions and
+     limitations under the License.
+ -->
+
+<resources xmlns:android="http://schemas.android.com/apk/res/android"
+    xmlns:xliff="urn:oasis:names:tc:xliff:document:1.2">
+    <string name="tethered_notification_title" msgid="6426563586025792944">"Tethering or hotspot active"</string>
+    <string name="tethered_notification_message" msgid="64800879503420696">"Tap to set up."</string>
+    <string name="disable_tether_notification_title" msgid="3004509127903564191">"Tethering is disabled"</string>
+    <string name="disable_tether_notification_message" msgid="6717523799293901476">"Contact your admin for details"</string>
+    <string name="notification_channel_tethering_status" msgid="2663463891530932727">"Hotspot and tethering status"</string>
+    <string name="no_upstream_notification_title" msgid="1204601824631788482"></string>
+    <string name="no_upstream_notification_message" msgid="8586582938243032621"></string>
+    <string name="no_upstream_notification_disable_button" msgid="8800919436924640822"></string>
+    <string name="upstream_roaming_notification_title" msgid="4772373823198997030"></string>
+    <string name="upstream_roaming_notification_message" msgid="3985577843181551650"></string>
+</resources>
diff --git a/Tethering/res/values-en-rXC/strings.xml b/Tethering/res/values-en-rXC/strings.xml
new file mode 100644
index 0000000..f1674be
--- /dev/null
+++ b/Tethering/res/values-en-rXC/strings.xml
@@ -0,0 +1,29 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!--  Copyright (C) 2020 The Android Open Source Project
+
+     Licensed under the Apache License, Version 2.0 (the "License");
+     you may not use this file except in compliance with the License.
+     You may obtain a copy of the License at
+
+          http://www.apache.org/licenses/LICENSE-2.0
+
+     Unless required by applicable law or agreed to in writing, software
+     distributed under the License is distributed on an "AS IS" BASIS,
+     WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+     See the License for the specific language governing permissions and
+     limitations under the License.
+ -->
+
+<resources xmlns:android="http://schemas.android.com/apk/res/android"
+    xmlns:xliff="urn:oasis:names:tc:xliff:document:1.2">
+    <string name="tethered_notification_title" msgid="6426563586025792944">"‎‏‎‎‎‎‎‏‎‏‏‏‎‎‎‎‎‎‏‎‎‏‎‎‎‎‏‏‏‏‏‏‏‏‎‏‏‎‎‏‎‎‏‎‏‏‏‏‏‎‏‏‏‏‎‏‏‎‎‎‏‎‎‎‎‎‏‏‎‏‏‏‏‎‎‎‎‏‏‏‎‎‏‎‎‏‎‏‏‎‏‏‎‎‎‎‎Tethering or hotspot active‎‏‎‎‏‎"</string>
+    <string name="tethered_notification_message" msgid="64800879503420696">"‎‏‎‎‎‎‎‏‎‏‏‏‎‎‎‎‎‎‏‎‎‏‎‎‎‎‏‏‏‏‎‎‎‏‏‏‎‎‏‏‎‎‎‏‏‏‎‎‎‎‎‎‎‏‏‏‎‎‏‏‏‏‎‏‏‏‏‏‎‏‏‏‏‎‎‏‎‏‏‎‏‎‎‎‏‏‎‎‎‎Tap to set up.‎‏‎‎‏‎"</string>
+    <string name="disable_tether_notification_title" msgid="3004509127903564191">"‎‏‎‎‎‎‎‏‎‏‏‏‎‎‎‎‎‎‏‎‎‏‎‎‎‎‏‏‏‏‏‏‎‏‎‏‎‎‏‏‎‏‏‎‎‏‎‎‎‏‎‏‎‎‏‎‎‏‎‎‎‏‎‎‎‎‏‏‏‎‏‎‎‎‏‏‏‎‎‎‏‎‏‎‎‎‏‏‎‎‏‏‏‏‏‎Tethering is disabled‎‏‎‎‏‎"</string>
+    <string name="disable_tether_notification_message" msgid="6717523799293901476">"‎‏‎‎‎‎‎‏‎‏‏‏‎‎‎‎‎‎‏‎‎‏‎‎‎‎‏‏‏‏‏‏‏‏‎‏‏‏‎‏‎‎‏‏‏‎‎‏‎‏‏‏‎‎‎‎‎‏‎‎‏‏‎‏‏‏‏‏‎‎‏‏‎‎‏‎‎‏‎‏‎‎‏‏‏‎‏‎‏‎‏‎‎‏‎‎‎Contact your admin for details‎‏‎‎‏‎"</string>
+    <string name="notification_channel_tethering_status" msgid="2663463891530932727">"‎‏‎‎‎‎‎‏‎‏‏‏‎‎‎‎‎‎‏‎‎‏‎‎‎‎‏‏‏‏‏‏‎‏‎‎‏‎‎‏‏‏‏‎‏‏‎‏‎‎‎‎‏‏‎‎‏‎‎‏‏‎‎‎‎‏‏‎‏‏‎‏‏‎‎‎‏‏‏‏‏‏‎‎‎‎‏‏‏‏‏‎‏‏‏‎Hotspot &amp; tethering status‎‏‎‎‏‎"</string>
+    <string name="no_upstream_notification_title" msgid="1204601824631788482"></string>
+    <string name="no_upstream_notification_message" msgid="8586582938243032621"></string>
+    <string name="no_upstream_notification_disable_button" msgid="8800919436924640822"></string>
+    <string name="upstream_roaming_notification_title" msgid="4772373823198997030"></string>
+    <string name="upstream_roaming_notification_message" msgid="3985577843181551650"></string>
+</resources>
diff --git a/Tethering/res/values-es-rUS/strings.xml b/Tethering/res/values-es-rUS/strings.xml
new file mode 100644
index 0000000..63689f4
--- /dev/null
+++ b/Tethering/res/values-es-rUS/strings.xml
@@ -0,0 +1,29 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!--  Copyright (C) 2020 The Android Open Source Project
+
+     Licensed under the Apache License, Version 2.0 (the "License");
+     you may not use this file except in compliance with the License.
+     You may obtain a copy of the License at
+
+          http://www.apache.org/licenses/LICENSE-2.0
+
+     Unless required by applicable law or agreed to in writing, software
+     distributed under the License is distributed on an "AS IS" BASIS,
+     WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+     See the License for the specific language governing permissions and
+     limitations under the License.
+ -->
+
+<resources xmlns:android="http://schemas.android.com/apk/res/android"
+    xmlns:xliff="urn:oasis:names:tc:xliff:document:1.2">
+    <string name="tethered_notification_title" msgid="6426563586025792944">"Conexión a red o hotspot conectados"</string>
+    <string name="tethered_notification_message" msgid="64800879503420696">"Presiona para configurar esta opción."</string>
+    <string name="disable_tether_notification_title" msgid="3004509127903564191">"Se inhabilitó la conexión mediante dispositivo portátil"</string>
+    <string name="disable_tether_notification_message" msgid="6717523799293901476">"Para obtener más información, comunícate con el administrador"</string>
+    <string name="notification_channel_tethering_status" msgid="2663463891530932727">"Estado del hotspot y la conexión mediante dispositivo portátil"</string>
+    <string name="no_upstream_notification_title" msgid="1204601824631788482"></string>
+    <string name="no_upstream_notification_message" msgid="8586582938243032621"></string>
+    <string name="no_upstream_notification_disable_button" msgid="8800919436924640822"></string>
+    <string name="upstream_roaming_notification_title" msgid="4772373823198997030"></string>
+    <string name="upstream_roaming_notification_message" msgid="3985577843181551650"></string>
+</resources>
diff --git a/Tethering/res/values-es/strings.xml b/Tethering/res/values-es/strings.xml
new file mode 100644
index 0000000..9a34ed5
--- /dev/null
+++ b/Tethering/res/values-es/strings.xml
@@ -0,0 +1,29 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!--  Copyright (C) 2020 The Android Open Source Project
+
+     Licensed under the Apache License, Version 2.0 (the "License");
+     you may not use this file except in compliance with the License.
+     You may obtain a copy of the License at
+
+          http://www.apache.org/licenses/LICENSE-2.0
+
+     Unless required by applicable law or agreed to in writing, software
+     distributed under the License is distributed on an "AS IS" BASIS,
+     WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+     See the License for the specific language governing permissions and
+     limitations under the License.
+ -->
+
+<resources xmlns:android="http://schemas.android.com/apk/res/android"
+    xmlns:xliff="urn:oasis:names:tc:xliff:document:1.2">
+    <string name="tethered_notification_title" msgid="6426563586025792944">"Conexión compartida o punto de acceso activos"</string>
+    <string name="tethered_notification_message" msgid="64800879503420696">"Toca para configurar."</string>
+    <string name="disable_tether_notification_title" msgid="3004509127903564191">"La conexión compartida está inhabilitada"</string>
+    <string name="disable_tether_notification_message" msgid="6717523799293901476">"Solicita más información a tu administrador"</string>
+    <string name="notification_channel_tethering_status" msgid="2663463891530932727">"Estado del punto de acceso y de la conexión compartida"</string>
+    <string name="no_upstream_notification_title" msgid="1204601824631788482"></string>
+    <string name="no_upstream_notification_message" msgid="8586582938243032621"></string>
+    <string name="no_upstream_notification_disable_button" msgid="8800919436924640822"></string>
+    <string name="upstream_roaming_notification_title" msgid="4772373823198997030"></string>
+    <string name="upstream_roaming_notification_message" msgid="3985577843181551650"></string>
+</resources>
diff --git a/Tethering/res/values-et/strings.xml b/Tethering/res/values-et/strings.xml
new file mode 100644
index 0000000..0970341
--- /dev/null
+++ b/Tethering/res/values-et/strings.xml
@@ -0,0 +1,29 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!--  Copyright (C) 2020 The Android Open Source Project
+
+     Licensed under the Apache License, Version 2.0 (the "License");
+     you may not use this file except in compliance with the License.
+     You may obtain a copy of the License at
+
+          http://www.apache.org/licenses/LICENSE-2.0
+
+     Unless required by applicable law or agreed to in writing, software
+     distributed under the License is distributed on an "AS IS" BASIS,
+     WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+     See the License for the specific language governing permissions and
+     limitations under the License.
+ -->
+
+<resources xmlns:android="http://schemas.android.com/apk/res/android"
+    xmlns:xliff="urn:oasis:names:tc:xliff:document:1.2">
+    <string name="tethered_notification_title" msgid="6426563586025792944">"Jagamine või kuumkoht on aktiivne"</string>
+    <string name="tethered_notification_message" msgid="64800879503420696">"Puudutage seadistamiseks."</string>
+    <string name="disable_tether_notification_title" msgid="3004509127903564191">"Jagamine on keelatud"</string>
+    <string name="disable_tether_notification_message" msgid="6717523799293901476">"Lisateabe saamiseks võtke ühendust oma administraatoriga"</string>
+    <string name="notification_channel_tethering_status" msgid="2663463891530932727">"Kuumkoha ja jagamise olek"</string>
+    <string name="no_upstream_notification_title" msgid="1204601824631788482"></string>
+    <string name="no_upstream_notification_message" msgid="8586582938243032621"></string>
+    <string name="no_upstream_notification_disable_button" msgid="8800919436924640822"></string>
+    <string name="upstream_roaming_notification_title" msgid="4772373823198997030"></string>
+    <string name="upstream_roaming_notification_message" msgid="3985577843181551650"></string>
+</resources>
diff --git a/Tethering/res/values-eu/strings.xml b/Tethering/res/values-eu/strings.xml
new file mode 100644
index 0000000..632019e
--- /dev/null
+++ b/Tethering/res/values-eu/strings.xml
@@ -0,0 +1,29 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!--  Copyright (C) 2020 The Android Open Source Project
+
+     Licensed under the Apache License, Version 2.0 (the "License");
+     you may not use this file except in compliance with the License.
+     You may obtain a copy of the License at
+
+          http://www.apache.org/licenses/LICENSE-2.0
+
+     Unless required by applicable law or agreed to in writing, software
+     distributed under the License is distributed on an "AS IS" BASIS,
+     WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+     See the License for the specific language governing permissions and
+     limitations under the License.
+ -->
+
+<resources xmlns:android="http://schemas.android.com/apk/res/android"
+    xmlns:xliff="urn:oasis:names:tc:xliff:document:1.2">
+    <string name="tethered_notification_title" msgid="6426563586025792944">"Konexioa partekatzea edo wifi-gunea aktibo dago"</string>
+    <string name="tethered_notification_message" msgid="64800879503420696">"Sakatu konfiguratzeko."</string>
+    <string name="disable_tether_notification_title" msgid="3004509127903564191">"Desgaituta dago konexioa partekatzeko aukera"</string>
+    <string name="disable_tether_notification_message" msgid="6717523799293901476">"Xehetasunak lortzeko, jarri administratzailearekin harremanetan"</string>
+    <string name="notification_channel_tethering_status" msgid="2663463891530932727">"Wifi-gunearen eta konexioa partekatzeko eginbidearen egoera"</string>
+    <string name="no_upstream_notification_title" msgid="1204601824631788482"></string>
+    <string name="no_upstream_notification_message" msgid="8586582938243032621"></string>
+    <string name="no_upstream_notification_disable_button" msgid="8800919436924640822"></string>
+    <string name="upstream_roaming_notification_title" msgid="4772373823198997030"></string>
+    <string name="upstream_roaming_notification_message" msgid="3985577843181551650"></string>
+</resources>
diff --git a/Tethering/res/values-fa/strings.xml b/Tethering/res/values-fa/strings.xml
new file mode 100644
index 0000000..2e21c85
--- /dev/null
+++ b/Tethering/res/values-fa/strings.xml
@@ -0,0 +1,29 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!--  Copyright (C) 2020 The Android Open Source Project
+
+     Licensed under the Apache License, Version 2.0 (the "License");
+     you may not use this file except in compliance with the License.
+     You may obtain a copy of the License at
+
+          http://www.apache.org/licenses/LICENSE-2.0
+
+     Unless required by applicable law or agreed to in writing, software
+     distributed under the License is distributed on an "AS IS" BASIS,
+     WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+     See the License for the specific language governing permissions and
+     limitations under the License.
+ -->
+
+<resources xmlns:android="http://schemas.android.com/apk/res/android"
+    xmlns:xliff="urn:oasis:names:tc:xliff:document:1.2">
+    <string name="tethered_notification_title" msgid="6426563586025792944">"اشتراک‌گذاری اینترنت یا نقطه اتصال فعال"</string>
+    <string name="tethered_notification_message" msgid="64800879503420696">"برای راه‌اندازی ضربه بزنید."</string>
+    <string name="disable_tether_notification_title" msgid="3004509127903564191">"اشتراک‌گذاری اینترنت غیرفعال است"</string>
+    <string name="disable_tether_notification_message" msgid="6717523799293901476">"برای جزئیات، با سرپرستتان تماس بگیرید"</string>
+    <string name="notification_channel_tethering_status" msgid="2663463891530932727">"وضعیت نقطه اتصال و اشتراک‌گذاری اینترنت"</string>
+    <string name="no_upstream_notification_title" msgid="1204601824631788482"></string>
+    <string name="no_upstream_notification_message" msgid="8586582938243032621"></string>
+    <string name="no_upstream_notification_disable_button" msgid="8800919436924640822"></string>
+    <string name="upstream_roaming_notification_title" msgid="4772373823198997030"></string>
+    <string name="upstream_roaming_notification_message" msgid="3985577843181551650"></string>
+</resources>
diff --git a/Tethering/res/values-fi/strings.xml b/Tethering/res/values-fi/strings.xml
new file mode 100644
index 0000000..413db3f
--- /dev/null
+++ b/Tethering/res/values-fi/strings.xml
@@ -0,0 +1,29 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!--  Copyright (C) 2020 The Android Open Source Project
+
+     Licensed under the Apache License, Version 2.0 (the "License");
+     you may not use this file except in compliance with the License.
+     You may obtain a copy of the License at
+
+          http://www.apache.org/licenses/LICENSE-2.0
+
+     Unless required by applicable law or agreed to in writing, software
+     distributed under the License is distributed on an "AS IS" BASIS,
+     WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+     See the License for the specific language governing permissions and
+     limitations under the License.
+ -->
+
+<resources xmlns:android="http://schemas.android.com/apk/res/android"
+    xmlns:xliff="urn:oasis:names:tc:xliff:document:1.2">
+    <string name="tethered_notification_title" msgid="6426563586025792944">"Yhteyden jakaminen tai hotspot käytössä"</string>
+    <string name="tethered_notification_message" msgid="64800879503420696">"Ota käyttöön napauttamalla."</string>
+    <string name="disable_tether_notification_title" msgid="3004509127903564191">"Yhteyden jakaminen on poistettu käytöstä"</string>
+    <string name="disable_tether_notification_message" msgid="6717523799293901476">"Pyydä lisätietoja järjestelmänvalvojalta"</string>
+    <string name="notification_channel_tethering_status" msgid="2663463891530932727">"Hotspotin ja yhteyden jakamisen tila"</string>
+    <string name="no_upstream_notification_title" msgid="1204601824631788482"></string>
+    <string name="no_upstream_notification_message" msgid="8586582938243032621"></string>
+    <string name="no_upstream_notification_disable_button" msgid="8800919436924640822"></string>
+    <string name="upstream_roaming_notification_title" msgid="4772373823198997030"></string>
+    <string name="upstream_roaming_notification_message" msgid="3985577843181551650"></string>
+</resources>
diff --git a/Tethering/res/values-fr-rCA/strings.xml b/Tethering/res/values-fr-rCA/strings.xml
new file mode 100644
index 0000000..eb2e4ba
--- /dev/null
+++ b/Tethering/res/values-fr-rCA/strings.xml
@@ -0,0 +1,29 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!--  Copyright (C) 2020 The Android Open Source Project
+
+     Licensed under the Apache License, Version 2.0 (the "License");
+     you may not use this file except in compliance with the License.
+     You may obtain a copy of the License at
+
+          http://www.apache.org/licenses/LICENSE-2.0
+
+     Unless required by applicable law or agreed to in writing, software
+     distributed under the License is distributed on an "AS IS" BASIS,
+     WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+     See the License for the specific language governing permissions and
+     limitations under the License.
+ -->
+
+<resources xmlns:android="http://schemas.android.com/apk/res/android"
+    xmlns:xliff="urn:oasis:names:tc:xliff:document:1.2">
+    <string name="tethered_notification_title" msgid="6426563586025792944">"Partage de connexion ou point d\'accès sans fil activé"</string>
+    <string name="tethered_notification_message" msgid="64800879503420696">"Touchez pour configurer."</string>
+    <string name="disable_tether_notification_title" msgid="3004509127903564191">"Le partage de connexion est désactivé"</string>
+    <string name="disable_tether_notification_message" msgid="6717523799293901476">"Communiquez avec votre administrateur pour obtenir plus de détails"</string>
+    <string name="notification_channel_tethering_status" msgid="2663463891530932727">"Point d\'accès et partage de connexion"</string>
+    <string name="no_upstream_notification_title" msgid="1204601824631788482"></string>
+    <string name="no_upstream_notification_message" msgid="8586582938243032621"></string>
+    <string name="no_upstream_notification_disable_button" msgid="8800919436924640822"></string>
+    <string name="upstream_roaming_notification_title" msgid="4772373823198997030"></string>
+    <string name="upstream_roaming_notification_message" msgid="3985577843181551650"></string>
+</resources>
diff --git a/Tethering/res/values-fr/strings.xml b/Tethering/res/values-fr/strings.xml
new file mode 100644
index 0000000..22259c5
--- /dev/null
+++ b/Tethering/res/values-fr/strings.xml
@@ -0,0 +1,29 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!--  Copyright (C) 2020 The Android Open Source Project
+
+     Licensed under the Apache License, Version 2.0 (the "License");
+     you may not use this file except in compliance with the License.
+     You may obtain a copy of the License at
+
+          http://www.apache.org/licenses/LICENSE-2.0
+
+     Unless required by applicable law or agreed to in writing, software
+     distributed under the License is distributed on an "AS IS" BASIS,
+     WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+     See the License for the specific language governing permissions and
+     limitations under the License.
+ -->
+
+<resources xmlns:android="http://schemas.android.com/apk/res/android"
+    xmlns:xliff="urn:oasis:names:tc:xliff:document:1.2">
+    <string name="tethered_notification_title" msgid="6426563586025792944">"Partage de connexion ou point d\'accès activé"</string>
+    <string name="tethered_notification_message" msgid="64800879503420696">"Appuyez pour effectuer la configuration."</string>
+    <string name="disable_tether_notification_title" msgid="3004509127903564191">"Le partage de connexion est désactivé"</string>
+    <string name="disable_tether_notification_message" msgid="6717523799293901476">"Pour en savoir plus, contactez votre administrateur"</string>
+    <string name="notification_channel_tethering_status" msgid="2663463891530932727">"État du point d\'accès et du partage de connexion"</string>
+    <string name="no_upstream_notification_title" msgid="1204601824631788482"></string>
+    <string name="no_upstream_notification_message" msgid="8586582938243032621"></string>
+    <string name="no_upstream_notification_disable_button" msgid="8800919436924640822"></string>
+    <string name="upstream_roaming_notification_title" msgid="4772373823198997030"></string>
+    <string name="upstream_roaming_notification_message" msgid="3985577843181551650"></string>
+</resources>
diff --git a/Tethering/res/values-gl/strings.xml b/Tethering/res/values-gl/strings.xml
new file mode 100644
index 0000000..ded82fc
--- /dev/null
+++ b/Tethering/res/values-gl/strings.xml
@@ -0,0 +1,29 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!--  Copyright (C) 2020 The Android Open Source Project
+
+     Licensed under the Apache License, Version 2.0 (the "License");
+     you may not use this file except in compliance with the License.
+     You may obtain a copy of the License at
+
+          http://www.apache.org/licenses/LICENSE-2.0
+
+     Unless required by applicable law or agreed to in writing, software
+     distributed under the License is distributed on an "AS IS" BASIS,
+     WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+     See the License for the specific language governing permissions and
+     limitations under the License.
+ -->
+
+<resources xmlns:android="http://schemas.android.com/apk/res/android"
+    xmlns:xliff="urn:oasis:names:tc:xliff:document:1.2">
+    <string name="tethered_notification_title" msgid="6426563586025792944">"Conexión compartida ou zona wifi activada"</string>
+    <string name="tethered_notification_message" msgid="64800879503420696">"Toca para configurar."</string>
+    <string name="disable_tether_notification_title" msgid="3004509127903564191">"A conexión compartida está desactivada"</string>
+    <string name="disable_tether_notification_message" msgid="6717523799293901476">"Contacta co administrador para obter información"</string>
+    <string name="notification_channel_tethering_status" msgid="2663463891530932727">"Estado da zona wifi e da conexión compartida"</string>
+    <string name="no_upstream_notification_title" msgid="1204601824631788482"></string>
+    <string name="no_upstream_notification_message" msgid="8586582938243032621"></string>
+    <string name="no_upstream_notification_disable_button" msgid="8800919436924640822"></string>
+    <string name="upstream_roaming_notification_title" msgid="4772373823198997030"></string>
+    <string name="upstream_roaming_notification_message" msgid="3985577843181551650"></string>
+</resources>
diff --git a/Tethering/res/values-gu/strings.xml b/Tethering/res/values-gu/strings.xml
new file mode 100644
index 0000000..7cbbc2d
--- /dev/null
+++ b/Tethering/res/values-gu/strings.xml
@@ -0,0 +1,29 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!--  Copyright (C) 2020 The Android Open Source Project
+
+     Licensed under the Apache License, Version 2.0 (the "License");
+     you may not use this file except in compliance with the License.
+     You may obtain a copy of the License at
+
+          http://www.apache.org/licenses/LICENSE-2.0
+
+     Unless required by applicable law or agreed to in writing, software
+     distributed under the License is distributed on an "AS IS" BASIS,
+     WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+     See the License for the specific language governing permissions and
+     limitations under the License.
+ -->
+
+<resources xmlns:android="http://schemas.android.com/apk/res/android"
+    xmlns:xliff="urn:oasis:names:tc:xliff:document:1.2">
+    <string name="tethered_notification_title" msgid="6426563586025792944">"ઇન્ટરનેટ શેર કરવાની સુવિધા અથવા હૉટસ્પૉટ સક્રિય છે"</string>
+    <string name="tethered_notification_message" msgid="64800879503420696">"સેટઅપ કરવા માટે ટૅપ કરો."</string>
+    <string name="disable_tether_notification_title" msgid="3004509127903564191">"ઇન્ટરનેટ શેર કરવાની સુવિધા બંધ કરી છે"</string>
+    <string name="disable_tether_notification_message" msgid="6717523799293901476">"વિગતો માટે તમારા વ્યવસ્થાપકનો સંપર્ક કરો"</string>
+    <string name="notification_channel_tethering_status" msgid="2663463891530932727">"હૉટસ્પૉટ અને ઇન્ટરનેટ શેર કરવાની સુવિધાનું સ્ટેટસ"</string>
+    <string name="no_upstream_notification_title" msgid="1204601824631788482"></string>
+    <string name="no_upstream_notification_message" msgid="8586582938243032621"></string>
+    <string name="no_upstream_notification_disable_button" msgid="8800919436924640822"></string>
+    <string name="upstream_roaming_notification_title" msgid="4772373823198997030"></string>
+    <string name="upstream_roaming_notification_message" msgid="3985577843181551650"></string>
+</resources>
diff --git a/Tethering/res/values-hi/strings.xml b/Tethering/res/values-hi/strings.xml
new file mode 100644
index 0000000..08af81b
--- /dev/null
+++ b/Tethering/res/values-hi/strings.xml
@@ -0,0 +1,29 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!--  Copyright (C) 2020 The Android Open Source Project
+
+     Licensed under the Apache License, Version 2.0 (the "License");
+     you may not use this file except in compliance with the License.
+     You may obtain a copy of the License at
+
+          http://www.apache.org/licenses/LICENSE-2.0
+
+     Unless required by applicable law or agreed to in writing, software
+     distributed under the License is distributed on an "AS IS" BASIS,
+     WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+     See the License for the specific language governing permissions and
+     limitations under the License.
+ -->
+
+<resources xmlns:android="http://schemas.android.com/apk/res/android"
+    xmlns:xliff="urn:oasis:names:tc:xliff:document:1.2">
+    <string name="tethered_notification_title" msgid="6426563586025792944">"टेदरिंग या हॉटस्पॉट चालू है"</string>
+    <string name="tethered_notification_message" msgid="64800879503420696">"सेट अप करने के लिए टैप करें."</string>
+    <string name="disable_tether_notification_title" msgid="3004509127903564191">"टेदरिंग बंद है"</string>
+    <string name="disable_tether_notification_message" msgid="6717523799293901476">"जानकारी के लिए अपने एडमिन से संपर्क करें"</string>
+    <string name="notification_channel_tethering_status" msgid="2663463891530932727">"हॉटस्पॉट और टेदरिंग की स्थिति"</string>
+    <string name="no_upstream_notification_title" msgid="1204601824631788482"></string>
+    <string name="no_upstream_notification_message" msgid="8586582938243032621"></string>
+    <string name="no_upstream_notification_disable_button" msgid="8800919436924640822"></string>
+    <string name="upstream_roaming_notification_title" msgid="4772373823198997030"></string>
+    <string name="upstream_roaming_notification_message" msgid="3985577843181551650"></string>
+</resources>
diff --git a/Tethering/res/values-hr/strings.xml b/Tethering/res/values-hr/strings.xml
new file mode 100644
index 0000000..827c135
--- /dev/null
+++ b/Tethering/res/values-hr/strings.xml
@@ -0,0 +1,29 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!--  Copyright (C) 2020 The Android Open Source Project
+
+     Licensed under the Apache License, Version 2.0 (the "License");
+     you may not use this file except in compliance with the License.
+     You may obtain a copy of the License at
+
+          http://www.apache.org/licenses/LICENSE-2.0
+
+     Unless required by applicable law or agreed to in writing, software
+     distributed under the License is distributed on an "AS IS" BASIS,
+     WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+     See the License for the specific language governing permissions and
+     limitations under the License.
+ -->
+
+<resources xmlns:android="http://schemas.android.com/apk/res/android"
+    xmlns:xliff="urn:oasis:names:tc:xliff:document:1.2">
+    <string name="tethered_notification_title" msgid="6426563586025792944">"Modemsko povezivanje ili žarišna točka aktivni"</string>
+    <string name="tethered_notification_message" msgid="64800879503420696">"Dodirnite da biste postavili."</string>
+    <string name="disable_tether_notification_title" msgid="3004509127903564191">"Modemsko je povezivanje onemogućeno"</string>
+    <string name="disable_tether_notification_message" msgid="6717523799293901476">"Obratite se administratoru da biste saznali pojedinosti"</string>
+    <string name="notification_channel_tethering_status" msgid="2663463891530932727">"Status žarišne točke i modemskog povezivanja"</string>
+    <string name="no_upstream_notification_title" msgid="1204601824631788482"></string>
+    <string name="no_upstream_notification_message" msgid="8586582938243032621"></string>
+    <string name="no_upstream_notification_disable_button" msgid="8800919436924640822"></string>
+    <string name="upstream_roaming_notification_title" msgid="4772373823198997030"></string>
+    <string name="upstream_roaming_notification_message" msgid="3985577843181551650"></string>
+</resources>
diff --git a/Tethering/res/values-hu/strings.xml b/Tethering/res/values-hu/strings.xml
new file mode 100644
index 0000000..eb68d6b
--- /dev/null
+++ b/Tethering/res/values-hu/strings.xml
@@ -0,0 +1,29 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!--  Copyright (C) 2020 The Android Open Source Project
+
+     Licensed under the Apache License, Version 2.0 (the "License");
+     you may not use this file except in compliance with the License.
+     You may obtain a copy of the License at
+
+          http://www.apache.org/licenses/LICENSE-2.0
+
+     Unless required by applicable law or agreed to in writing, software
+     distributed under the License is distributed on an "AS IS" BASIS,
+     WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+     See the License for the specific language governing permissions and
+     limitations under the License.
+ -->
+
+<resources xmlns:android="http://schemas.android.com/apk/res/android"
+    xmlns:xliff="urn:oasis:names:tc:xliff:document:1.2">
+    <string name="tethered_notification_title" msgid="6426563586025792944">"Megosztás vagy aktív hotspot"</string>
+    <string name="tethered_notification_message" msgid="64800879503420696">"Koppintson a beállításhoz."</string>
+    <string name="disable_tether_notification_title" msgid="3004509127903564191">"Az internetmegosztás le van tiltva"</string>
+    <string name="disable_tether_notification_message" msgid="6717523799293901476">"A részletekért forduljon rendszergazdájához"</string>
+    <string name="notification_channel_tethering_status" msgid="2663463891530932727">"Hotspot és internetmegosztás állapota"</string>
+    <string name="no_upstream_notification_title" msgid="1204601824631788482"></string>
+    <string name="no_upstream_notification_message" msgid="8586582938243032621"></string>
+    <string name="no_upstream_notification_disable_button" msgid="8800919436924640822"></string>
+    <string name="upstream_roaming_notification_title" msgid="4772373823198997030"></string>
+    <string name="upstream_roaming_notification_message" msgid="3985577843181551650"></string>
+</resources>
diff --git a/Tethering/res/values-hy/strings.xml b/Tethering/res/values-hy/strings.xml
new file mode 100644
index 0000000..912941e
--- /dev/null
+++ b/Tethering/res/values-hy/strings.xml
@@ -0,0 +1,29 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!--  Copyright (C) 2020 The Android Open Source Project
+
+     Licensed under the Apache License, Version 2.0 (the "License");
+     you may not use this file except in compliance with the License.
+     You may obtain a copy of the License at
+
+          http://www.apache.org/licenses/LICENSE-2.0
+
+     Unless required by applicable law or agreed to in writing, software
+     distributed under the License is distributed on an "AS IS" BASIS,
+     WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+     See the License for the specific language governing permissions and
+     limitations under the License.
+ -->
+
+<resources xmlns:android="http://schemas.android.com/apk/res/android"
+    xmlns:xliff="urn:oasis:names:tc:xliff:document:1.2">
+    <string name="tethered_notification_title" msgid="6426563586025792944">"Մոդեմի ռեժիմը միացված է"</string>
+    <string name="tethered_notification_message" msgid="64800879503420696">"Հպեք՝ կարգավորելու համար։"</string>
+    <string name="disable_tether_notification_title" msgid="3004509127903564191">"Մոդեմի ռեժիմն անջատված է"</string>
+    <string name="disable_tether_notification_message" msgid="6717523799293901476">"Մանրամասների համար դիմեք ձեր ադմինիստրատորին"</string>
+    <string name="notification_channel_tethering_status" msgid="2663463891530932727">"Թեժ կետի և մոդեմի ռեժիմի կարգավիճակը"</string>
+    <string name="no_upstream_notification_title" msgid="1204601824631788482"></string>
+    <string name="no_upstream_notification_message" msgid="8586582938243032621"></string>
+    <string name="no_upstream_notification_disable_button" msgid="8800919436924640822"></string>
+    <string name="upstream_roaming_notification_title" msgid="4772373823198997030"></string>
+    <string name="upstream_roaming_notification_message" msgid="3985577843181551650"></string>
+</resources>
diff --git a/Tethering/res/values-in/strings.xml b/Tethering/res/values-in/strings.xml
new file mode 100644
index 0000000..a4e175a
--- /dev/null
+++ b/Tethering/res/values-in/strings.xml
@@ -0,0 +1,29 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!--  Copyright (C) 2020 The Android Open Source Project
+
+     Licensed under the Apache License, Version 2.0 (the "License");
+     you may not use this file except in compliance with the License.
+     You may obtain a copy of the License at
+
+          http://www.apache.org/licenses/LICENSE-2.0
+
+     Unless required by applicable law or agreed to in writing, software
+     distributed under the License is distributed on an "AS IS" BASIS,
+     WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+     See the License for the specific language governing permissions and
+     limitations under the License.
+ -->
+
+<resources xmlns:android="http://schemas.android.com/apk/res/android"
+    xmlns:xliff="urn:oasis:names:tc:xliff:document:1.2">
+    <string name="tethered_notification_title" msgid="6426563586025792944">"Tethering atau hotspot aktif"</string>
+    <string name="tethered_notification_message" msgid="64800879503420696">"Ketuk untuk menyiapkan."</string>
+    <string name="disable_tether_notification_title" msgid="3004509127903564191">"Tethering dinonaktifkan"</string>
+    <string name="disable_tether_notification_message" msgid="6717523799293901476">"Hubungi admin untuk mengetahui detailnya"</string>
+    <string name="notification_channel_tethering_status" msgid="2663463891530932727">"Status hotspot &amp; tethering"</string>
+    <string name="no_upstream_notification_title" msgid="1204601824631788482"></string>
+    <string name="no_upstream_notification_message" msgid="8586582938243032621"></string>
+    <string name="no_upstream_notification_disable_button" msgid="8800919436924640822"></string>
+    <string name="upstream_roaming_notification_title" msgid="4772373823198997030"></string>
+    <string name="upstream_roaming_notification_message" msgid="3985577843181551650"></string>
+</resources>
diff --git a/Tethering/res/values-is/strings.xml b/Tethering/res/values-is/strings.xml
new file mode 100644
index 0000000..e9f6670
--- /dev/null
+++ b/Tethering/res/values-is/strings.xml
@@ -0,0 +1,29 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!--  Copyright (C) 2020 The Android Open Source Project
+
+     Licensed under the Apache License, Version 2.0 (the "License");
+     you may not use this file except in compliance with the License.
+     You may obtain a copy of the License at
+
+          http://www.apache.org/licenses/LICENSE-2.0
+
+     Unless required by applicable law or agreed to in writing, software
+     distributed under the License is distributed on an "AS IS" BASIS,
+     WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+     See the License for the specific language governing permissions and
+     limitations under the License.
+ -->
+
+<resources xmlns:android="http://schemas.android.com/apk/res/android"
+    xmlns:xliff="urn:oasis:names:tc:xliff:document:1.2">
+    <string name="tethered_notification_title" msgid="6426563586025792944">"Kveikt á tjóðrun eða aðgangsstað"</string>
+    <string name="tethered_notification_message" msgid="64800879503420696">"Ýttu til að setja upp."</string>
+    <string name="disable_tether_notification_title" msgid="3004509127903564191">"Slökkt er á tjóðrun"</string>
+    <string name="disable_tether_notification_message" msgid="6717523799293901476">"Hafðu samband við kerfisstjórann til að fá upplýsingar"</string>
+    <string name="notification_channel_tethering_status" msgid="2663463891530932727">"Staða heits reits og tjóðrunar"</string>
+    <string name="no_upstream_notification_title" msgid="1204601824631788482"></string>
+    <string name="no_upstream_notification_message" msgid="8586582938243032621"></string>
+    <string name="no_upstream_notification_disable_button" msgid="8800919436924640822"></string>
+    <string name="upstream_roaming_notification_title" msgid="4772373823198997030"></string>
+    <string name="upstream_roaming_notification_message" msgid="3985577843181551650"></string>
+</resources>
diff --git a/Tethering/res/values-it/strings.xml b/Tethering/res/values-it/strings.xml
new file mode 100644
index 0000000..ffb9196
--- /dev/null
+++ b/Tethering/res/values-it/strings.xml
@@ -0,0 +1,29 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!--  Copyright (C) 2020 The Android Open Source Project
+
+     Licensed under the Apache License, Version 2.0 (the "License");
+     you may not use this file except in compliance with the License.
+     You may obtain a copy of the License at
+
+          http://www.apache.org/licenses/LICENSE-2.0
+
+     Unless required by applicable law or agreed to in writing, software
+     distributed under the License is distributed on an "AS IS" BASIS,
+     WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+     See the License for the specific language governing permissions and
+     limitations under the License.
+ -->
+
+<resources xmlns:android="http://schemas.android.com/apk/res/android"
+    xmlns:xliff="urn:oasis:names:tc:xliff:document:1.2">
+    <string name="tethered_notification_title" msgid="6426563586025792944">"Hotspot o tethering attivo"</string>
+    <string name="tethered_notification_message" msgid="64800879503420696">"Tocca per impostare."</string>
+    <string name="disable_tether_notification_title" msgid="3004509127903564191">"Tethering disattivato"</string>
+    <string name="disable_tether_notification_message" msgid="6717523799293901476">"Contatta il tuo amministratore per avere informazioni dettagliate"</string>
+    <string name="notification_channel_tethering_status" msgid="2663463891530932727">"Stato hotspot e tethering"</string>
+    <string name="no_upstream_notification_title" msgid="1204601824631788482"></string>
+    <string name="no_upstream_notification_message" msgid="8586582938243032621"></string>
+    <string name="no_upstream_notification_disable_button" msgid="8800919436924640822"></string>
+    <string name="upstream_roaming_notification_title" msgid="4772373823198997030"></string>
+    <string name="upstream_roaming_notification_message" msgid="3985577843181551650"></string>
+</resources>
diff --git a/Tethering/res/values-iw/strings.xml b/Tethering/res/values-iw/strings.xml
new file mode 100644
index 0000000..7adcb47
--- /dev/null
+++ b/Tethering/res/values-iw/strings.xml
@@ -0,0 +1,29 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!--  Copyright (C) 2020 The Android Open Source Project
+
+     Licensed under the Apache License, Version 2.0 (the "License");
+     you may not use this file except in compliance with the License.
+     You may obtain a copy of the License at
+
+          http://www.apache.org/licenses/LICENSE-2.0
+
+     Unless required by applicable law or agreed to in writing, software
+     distributed under the License is distributed on an "AS IS" BASIS,
+     WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+     See the License for the specific language governing permissions and
+     limitations under the License.
+ -->
+
+<resources xmlns:android="http://schemas.android.com/apk/res/android"
+    xmlns:xliff="urn:oasis:names:tc:xliff:document:1.2">
+    <string name="tethered_notification_title" msgid="6426563586025792944">"נקודה לשיתוף אינטרנט או שיתוף אינטרנט בין מכשירים: בסטטוס פעיל"</string>
+    <string name="tethered_notification_message" msgid="64800879503420696">"יש להקיש כדי להגדיר."</string>
+    <string name="disable_tether_notification_title" msgid="3004509127903564191">"שיתוף האינטרנט בין מכשירים מושבת"</string>
+    <string name="disable_tether_notification_message" msgid="6717523799293901476">"לפרטים, יש לפנות למנהל המערכת"</string>
+    <string name="notification_channel_tethering_status" msgid="2663463891530932727">"סטטוס של נקודה לשיתוף אינטרנט ושיתוף אינטרנט בין מכשירים"</string>
+    <string name="no_upstream_notification_title" msgid="1204601824631788482"></string>
+    <string name="no_upstream_notification_message" msgid="8586582938243032621"></string>
+    <string name="no_upstream_notification_disable_button" msgid="8800919436924640822"></string>
+    <string name="upstream_roaming_notification_title" msgid="4772373823198997030"></string>
+    <string name="upstream_roaming_notification_message" msgid="3985577843181551650"></string>
+</resources>
diff --git a/Tethering/res/values-ja/strings.xml b/Tethering/res/values-ja/strings.xml
new file mode 100644
index 0000000..f68a730
--- /dev/null
+++ b/Tethering/res/values-ja/strings.xml
@@ -0,0 +1,29 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!--  Copyright (C) 2020 The Android Open Source Project
+
+     Licensed under the Apache License, Version 2.0 (the "License");
+     you may not use this file except in compliance with the License.
+     You may obtain a copy of the License at
+
+          http://www.apache.org/licenses/LICENSE-2.0
+
+     Unless required by applicable law or agreed to in writing, software
+     distributed under the License is distributed on an "AS IS" BASIS,
+     WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+     See the License for the specific language governing permissions and
+     limitations under the License.
+ -->
+
+<resources xmlns:android="http://schemas.android.com/apk/res/android"
+    xmlns:xliff="urn:oasis:names:tc:xliff:document:1.2">
+    <string name="tethered_notification_title" msgid="6426563586025792944">"テザリングまたはアクセス ポイントが有効です"</string>
+    <string name="tethered_notification_message" msgid="64800879503420696">"タップしてセットアップします。"</string>
+    <string name="disable_tether_notification_title" msgid="3004509127903564191">"テザリングは無効に設定されています"</string>
+    <string name="disable_tether_notification_message" msgid="6717523799293901476">"詳しくは、管理者にお問い合わせください"</string>
+    <string name="notification_channel_tethering_status" msgid="2663463891530932727">"アクセス ポイントとテザリングのステータス"</string>
+    <string name="no_upstream_notification_title" msgid="1204601824631788482"></string>
+    <string name="no_upstream_notification_message" msgid="8586582938243032621"></string>
+    <string name="no_upstream_notification_disable_button" msgid="8800919436924640822"></string>
+    <string name="upstream_roaming_notification_title" msgid="4772373823198997030"></string>
+    <string name="upstream_roaming_notification_message" msgid="3985577843181551650"></string>
+</resources>
diff --git a/Tethering/res/values-ka/strings.xml b/Tethering/res/values-ka/strings.xml
new file mode 100644
index 0000000..7c22e82
--- /dev/null
+++ b/Tethering/res/values-ka/strings.xml
@@ -0,0 +1,29 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!--  Copyright (C) 2020 The Android Open Source Project
+
+     Licensed under the Apache License, Version 2.0 (the "License");
+     you may not use this file except in compliance with the License.
+     You may obtain a copy of the License at
+
+          http://www.apache.org/licenses/LICENSE-2.0
+
+     Unless required by applicable law or agreed to in writing, software
+     distributed under the License is distributed on an "AS IS" BASIS,
+     WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+     See the License for the specific language governing permissions and
+     limitations under the License.
+ -->
+
+<resources xmlns:android="http://schemas.android.com/apk/res/android"
+    xmlns:xliff="urn:oasis:names:tc:xliff:document:1.2">
+    <string name="tethered_notification_title" msgid="6426563586025792944">"ტეტერინგი ან უსადენო ქსელი აქტიურია"</string>
+    <string name="tethered_notification_message" msgid="64800879503420696">"შეეხეთ დასაყენებლად."</string>
+    <string name="disable_tether_notification_title" msgid="3004509127903564191">"ტეტერინგი გათიშულია"</string>
+    <string name="disable_tether_notification_message" msgid="6717523799293901476">"დამატებითი ინფორმაციისთვის დაუკავშირდით თქვენს ადმინისტრატორს"</string>
+    <string name="notification_channel_tethering_status" msgid="2663463891530932727">"უსადენო ქსელის და ტეტერინგის სტატუსი"</string>
+    <string name="no_upstream_notification_title" msgid="1204601824631788482"></string>
+    <string name="no_upstream_notification_message" msgid="8586582938243032621"></string>
+    <string name="no_upstream_notification_disable_button" msgid="8800919436924640822"></string>
+    <string name="upstream_roaming_notification_title" msgid="4772373823198997030"></string>
+    <string name="upstream_roaming_notification_message" msgid="3985577843181551650"></string>
+</resources>
diff --git a/Tethering/res/values-kk/strings.xml b/Tethering/res/values-kk/strings.xml
new file mode 100644
index 0000000..0857d06
--- /dev/null
+++ b/Tethering/res/values-kk/strings.xml
@@ -0,0 +1,29 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!--  Copyright (C) 2020 The Android Open Source Project
+
+     Licensed under the Apache License, Version 2.0 (the "License");
+     you may not use this file except in compliance with the License.
+     You may obtain a copy of the License at
+
+          http://www.apache.org/licenses/LICENSE-2.0
+
+     Unless required by applicable law or agreed to in writing, software
+     distributed under the License is distributed on an "AS IS" BASIS,
+     WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+     See the License for the specific language governing permissions and
+     limitations under the License.
+ -->
+
+<resources xmlns:android="http://schemas.android.com/apk/res/android"
+    xmlns:xliff="urn:oasis:names:tc:xliff:document:1.2">
+    <string name="tethered_notification_title" msgid="6426563586025792944">"Тетеринг немесе хотспот қосулы"</string>
+    <string name="tethered_notification_message" msgid="64800879503420696">"Реттеу үшін түртіңіз."</string>
+    <string name="disable_tether_notification_title" msgid="3004509127903564191">"Тетеринг өшірілді."</string>
+    <string name="disable_tether_notification_message" msgid="6717523799293901476">"Мәліметтерді әкімшіден алыңыз."</string>
+    <string name="notification_channel_tethering_status" msgid="2663463891530932727">"Хотспот және тетеринг күйі"</string>
+    <string name="no_upstream_notification_title" msgid="1204601824631788482"></string>
+    <string name="no_upstream_notification_message" msgid="8586582938243032621"></string>
+    <string name="no_upstream_notification_disable_button" msgid="8800919436924640822"></string>
+    <string name="upstream_roaming_notification_title" msgid="4772373823198997030"></string>
+    <string name="upstream_roaming_notification_message" msgid="3985577843181551650"></string>
+</resources>
diff --git a/Tethering/res/values-km/strings.xml b/Tethering/res/values-km/strings.xml
new file mode 100644
index 0000000..536e3d1
--- /dev/null
+++ b/Tethering/res/values-km/strings.xml
@@ -0,0 +1,29 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!--  Copyright (C) 2020 The Android Open Source Project
+
+     Licensed under the Apache License, Version 2.0 (the "License");
+     you may not use this file except in compliance with the License.
+     You may obtain a copy of the License at
+
+          http://www.apache.org/licenses/LICENSE-2.0
+
+     Unless required by applicable law or agreed to in writing, software
+     distributed under the License is distributed on an "AS IS" BASIS,
+     WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+     See the License for the specific language governing permissions and
+     limitations under the License.
+ -->
+
+<resources xmlns:android="http://schemas.android.com/apk/res/android"
+    xmlns:xliff="urn:oasis:names:tc:xliff:document:1.2">
+    <string name="tethered_notification_title" msgid="6426563586025792944">"ការភ្ជាប់ ឬហតស្ប៉ត​កំពុងដំណើរការ"</string>
+    <string name="tethered_notification_message" msgid="64800879503420696">"ចុច​ដើម្បី​រៀបចំ។"</string>
+    <string name="disable_tether_notification_title" msgid="3004509127903564191">"ការភ្ជាប់​ត្រូវបានបិទ"</string>
+    <string name="disable_tether_notification_message" msgid="6717523799293901476">"ទាក់ទងអ្នកគ្រប់គ្រង​របស់អ្នក ដើម្បីទទួលបានព័ត៌មានលម្អិត"</string>
+    <string name="notification_channel_tethering_status" msgid="2663463891530932727">"ស្ថានភាពនៃការភ្ជាប់ និងហតស្ប៉ត"</string>
+    <string name="no_upstream_notification_title" msgid="1204601824631788482"></string>
+    <string name="no_upstream_notification_message" msgid="8586582938243032621"></string>
+    <string name="no_upstream_notification_disable_button" msgid="8800919436924640822"></string>
+    <string name="upstream_roaming_notification_title" msgid="4772373823198997030"></string>
+    <string name="upstream_roaming_notification_message" msgid="3985577843181551650"></string>
+</resources>
diff --git a/Tethering/res/values-kn/strings.xml b/Tethering/res/values-kn/strings.xml
new file mode 100644
index 0000000..32f5492
--- /dev/null
+++ b/Tethering/res/values-kn/strings.xml
@@ -0,0 +1,29 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!--  Copyright (C) 2020 The Android Open Source Project
+
+     Licensed under the Apache License, Version 2.0 (the "License");
+     you may not use this file except in compliance with the License.
+     You may obtain a copy of the License at
+
+          http://www.apache.org/licenses/LICENSE-2.0
+
+     Unless required by applicable law or agreed to in writing, software
+     distributed under the License is distributed on an "AS IS" BASIS,
+     WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+     See the License for the specific language governing permissions and
+     limitations under the License.
+ -->
+
+<resources xmlns:android="http://schemas.android.com/apk/res/android"
+    xmlns:xliff="urn:oasis:names:tc:xliff:document:1.2">
+    <string name="tethered_notification_title" msgid="6426563586025792944">"ಟೆಥರಿಂಗ್ ಅಥವಾ ಹಾಟ್‌ಸ್ಪಾಟ್ ಸಕ್ರಿಯವಾಗಿದೆ"</string>
+    <string name="tethered_notification_message" msgid="64800879503420696">"ಸೆಟಪ್ ಮಾಡಲು ಟ್ಯಾಪ್ ಮಾಡಿ."</string>
+    <string name="disable_tether_notification_title" msgid="3004509127903564191">"ಟೆಥರಿಂಗ್ ಅನ್ನು ನಿಷ್ಕ್ರಿಯಗೊಳಿಸಲಾಗಿದೆ"</string>
+    <string name="disable_tether_notification_message" msgid="6717523799293901476">"ವಿವರಗಳಿಗಾಗಿ ನಿಮ್ಮ ನಿರ್ವಾಹಕರನ್ನು ಸಂಪರ್ಕಿಸಿ"</string>
+    <string name="notification_channel_tethering_status" msgid="2663463891530932727">"ಹಾಟ್‌ಸ್ಪಾಟ್ ಮತ್ತು ಟೆಥರಿಂಗ್‌ ಸ್ಥಿತಿ"</string>
+    <string name="no_upstream_notification_title" msgid="1204601824631788482"></string>
+    <string name="no_upstream_notification_message" msgid="8586582938243032621"></string>
+    <string name="no_upstream_notification_disable_button" msgid="8800919436924640822"></string>
+    <string name="upstream_roaming_notification_title" msgid="4772373823198997030"></string>
+    <string name="upstream_roaming_notification_message" msgid="3985577843181551650"></string>
+</resources>
diff --git a/Tethering/res/values-ko/strings.xml b/Tethering/res/values-ko/strings.xml
new file mode 100644
index 0000000..156b247
--- /dev/null
+++ b/Tethering/res/values-ko/strings.xml
@@ -0,0 +1,29 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!--  Copyright (C) 2020 The Android Open Source Project
+
+     Licensed under the Apache License, Version 2.0 (the "License");
+     you may not use this file except in compliance with the License.
+     You may obtain a copy of the License at
+
+          http://www.apache.org/licenses/LICENSE-2.0
+
+     Unless required by applicable law or agreed to in writing, software
+     distributed under the License is distributed on an "AS IS" BASIS,
+     WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+     See the License for the specific language governing permissions and
+     limitations under the License.
+ -->
+
+<resources xmlns:android="http://schemas.android.com/apk/res/android"
+    xmlns:xliff="urn:oasis:names:tc:xliff:document:1.2">
+    <string name="tethered_notification_title" msgid="6426563586025792944">"테더링 또는 핫스팟 사용"</string>
+    <string name="tethered_notification_message" msgid="64800879503420696">"설정하려면 탭하세요."</string>
+    <string name="disable_tether_notification_title" msgid="3004509127903564191">"테더링이 사용 중지됨"</string>
+    <string name="disable_tether_notification_message" msgid="6717523799293901476">"자세한 정보는 관리자에게 문의하세요."</string>
+    <string name="notification_channel_tethering_status" msgid="2663463891530932727">"핫스팟 및 테더링 상태"</string>
+    <string name="no_upstream_notification_title" msgid="1204601824631788482"></string>
+    <string name="no_upstream_notification_message" msgid="8586582938243032621"></string>
+    <string name="no_upstream_notification_disable_button" msgid="8800919436924640822"></string>
+    <string name="upstream_roaming_notification_title" msgid="4772373823198997030"></string>
+    <string name="upstream_roaming_notification_message" msgid="3985577843181551650"></string>
+</resources>
diff --git a/Tethering/res/values-ky/strings.xml b/Tethering/res/values-ky/strings.xml
new file mode 100644
index 0000000..18ee5fd
--- /dev/null
+++ b/Tethering/res/values-ky/strings.xml
@@ -0,0 +1,29 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!--  Copyright (C) 2020 The Android Open Source Project
+
+     Licensed under the Apache License, Version 2.0 (the "License");
+     you may not use this file except in compliance with the License.
+     You may obtain a copy of the License at
+
+          http://www.apache.org/licenses/LICENSE-2.0
+
+     Unless required by applicable law or agreed to in writing, software
+     distributed under the License is distributed on an "AS IS" BASIS,
+     WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+     See the License for the specific language governing permissions and
+     limitations under the License.
+ -->
+
+<resources xmlns:android="http://schemas.android.com/apk/res/android"
+    xmlns:xliff="urn:oasis:names:tc:xliff:document:1.2">
+    <string name="tethered_notification_title" msgid="6426563586025792944">"Модем режими күйүп турат"</string>
+    <string name="tethered_notification_message" msgid="64800879503420696">"Жөндөө үчүн таптап коюңуз."</string>
+    <string name="disable_tether_notification_title" msgid="3004509127903564191">"Телефонду модем катары колдонууга болбойт"</string>
+    <string name="disable_tether_notification_message" msgid="6717523799293901476">"Кеңири маалымат үчүн администраторуңузга кайрылыңыз"</string>
+    <string name="notification_channel_tethering_status" msgid="2663463891530932727">"Байланыш түйүнүнүн жана модем режиминин статусу"</string>
+    <string name="no_upstream_notification_title" msgid="1204601824631788482"></string>
+    <string name="no_upstream_notification_message" msgid="8586582938243032621"></string>
+    <string name="no_upstream_notification_disable_button" msgid="8800919436924640822"></string>
+    <string name="upstream_roaming_notification_title" msgid="4772373823198997030"></string>
+    <string name="upstream_roaming_notification_message" msgid="3985577843181551650"></string>
+</resources>
diff --git a/Tethering/res/values-lo/strings.xml b/Tethering/res/values-lo/strings.xml
new file mode 100644
index 0000000..b127670
--- /dev/null
+++ b/Tethering/res/values-lo/strings.xml
@@ -0,0 +1,29 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!--  Copyright (C) 2020 The Android Open Source Project
+
+     Licensed under the Apache License, Version 2.0 (the "License");
+     you may not use this file except in compliance with the License.
+     You may obtain a copy of the License at
+
+          http://www.apache.org/licenses/LICENSE-2.0
+
+     Unless required by applicable law or agreed to in writing, software
+     distributed under the License is distributed on an "AS IS" BASIS,
+     WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+     See the License for the specific language governing permissions and
+     limitations under the License.
+ -->
+
+<resources xmlns:android="http://schemas.android.com/apk/res/android"
+    xmlns:xliff="urn:oasis:names:tc:xliff:document:1.2">
+    <string name="tethered_notification_title" msgid="6426563586025792944">"ເປີດການປ່ອຍສັນຍານ ຫຼື ຮັອດສະປອດແລ້ວ"</string>
+    <string name="tethered_notification_message" msgid="64800879503420696">"ແຕະເພື່ອຕັ້ງຄ່າ."</string>
+    <string name="disable_tether_notification_title" msgid="3004509127903564191">"ການປ່ອຍສັນຍານຖືກປິດໄວ້"</string>
+    <string name="disable_tether_notification_message" msgid="6717523799293901476">"ຕິດຕໍ່ຜູ້ເບິ່ງແຍງລະບົບສຳລັບລາຍລະອຽດ"</string>
+    <string name="notification_channel_tethering_status" msgid="2663463891530932727">"ສະຖານະຮັອດສະປອດ ແລະ ການປ່ອຍສັນຍານ"</string>
+    <string name="no_upstream_notification_title" msgid="1204601824631788482"></string>
+    <string name="no_upstream_notification_message" msgid="8586582938243032621"></string>
+    <string name="no_upstream_notification_disable_button" msgid="8800919436924640822"></string>
+    <string name="upstream_roaming_notification_title" msgid="4772373823198997030"></string>
+    <string name="upstream_roaming_notification_message" msgid="3985577843181551650"></string>
+</resources>
diff --git a/Tethering/res/values-lt/strings.xml b/Tethering/res/values-lt/strings.xml
new file mode 100644
index 0000000..8427baf
--- /dev/null
+++ b/Tethering/res/values-lt/strings.xml
@@ -0,0 +1,29 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!--  Copyright (C) 2020 The Android Open Source Project
+
+     Licensed under the Apache License, Version 2.0 (the "License");
+     you may not use this file except in compliance with the License.
+     You may obtain a copy of the License at
+
+          http://www.apache.org/licenses/LICENSE-2.0
+
+     Unless required by applicable law or agreed to in writing, software
+     distributed under the License is distributed on an "AS IS" BASIS,
+     WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+     See the License for the specific language governing permissions and
+     limitations under the License.
+ -->
+
+<resources xmlns:android="http://schemas.android.com/apk/res/android"
+    xmlns:xliff="urn:oasis:names:tc:xliff:document:1.2">
+    <string name="tethered_notification_title" msgid="6426563586025792944">"Įrenginys naudojamas kaip modemas arba įjungtas viešosios interneto prieigos taškas"</string>
+    <string name="tethered_notification_message" msgid="64800879503420696">"Palieskite, kad nustatytumėte."</string>
+    <string name="disable_tether_notification_title" msgid="3004509127903564191">"Įrenginio kaip modemo naudojimas išjungtas"</string>
+    <string name="disable_tether_notification_message" msgid="6717523799293901476">"Jei reikia išsamios informacijos, susisiekite su administratoriumi"</string>
+    <string name="notification_channel_tethering_status" msgid="2663463891530932727">"Viešosios interneto prieigos taško ir įrenginio kaip modemo naudojimo būsena"</string>
+    <string name="no_upstream_notification_title" msgid="1204601824631788482"></string>
+    <string name="no_upstream_notification_message" msgid="8586582938243032621"></string>
+    <string name="no_upstream_notification_disable_button" msgid="8800919436924640822"></string>
+    <string name="upstream_roaming_notification_title" msgid="4772373823198997030"></string>
+    <string name="upstream_roaming_notification_message" msgid="3985577843181551650"></string>
+</resources>
diff --git a/Tethering/res/values-lv/strings.xml b/Tethering/res/values-lv/strings.xml
new file mode 100644
index 0000000..aa2d699
--- /dev/null
+++ b/Tethering/res/values-lv/strings.xml
@@ -0,0 +1,29 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!--  Copyright (C) 2020 The Android Open Source Project
+
+     Licensed under the Apache License, Version 2.0 (the "License");
+     you may not use this file except in compliance with the License.
+     You may obtain a copy of the License at
+
+          http://www.apache.org/licenses/LICENSE-2.0
+
+     Unless required by applicable law or agreed to in writing, software
+     distributed under the License is distributed on an "AS IS" BASIS,
+     WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+     See the License for the specific language governing permissions and
+     limitations under the License.
+ -->
+
+<resources xmlns:android="http://schemas.android.com/apk/res/android"
+    xmlns:xliff="urn:oasis:names:tc:xliff:document:1.2">
+    <string name="tethered_notification_title" msgid="6426563586025792944">"Piesaiste vai tīklājs ir aktīvs."</string>
+    <string name="tethered_notification_message" msgid="64800879503420696">"Pieskarieties, lai to iestatītu."</string>
+    <string name="disable_tether_notification_title" msgid="3004509127903564191">"Piesaiste ir atspējota"</string>
+    <string name="disable_tether_notification_message" msgid="6717523799293901476">"Lai iegūtu detalizētu informāciju, sazinieties ar savu administratoru."</string>
+    <string name="notification_channel_tethering_status" msgid="2663463891530932727">"Tīklāja un piesaistes statuss"</string>
+    <string name="no_upstream_notification_title" msgid="1204601824631788482"></string>
+    <string name="no_upstream_notification_message" msgid="8586582938243032621"></string>
+    <string name="no_upstream_notification_disable_button" msgid="8800919436924640822"></string>
+    <string name="upstream_roaming_notification_title" msgid="4772373823198997030"></string>
+    <string name="upstream_roaming_notification_message" msgid="3985577843181551650"></string>
+</resources>
diff --git a/Tethering/res/values-mcc310-mnc004-af/strings.xml b/Tethering/res/values-mcc310-mnc004-af/strings.xml
new file mode 100644
index 0000000..19d659c
--- /dev/null
+++ b/Tethering/res/values-mcc310-mnc004-af/strings.xml
@@ -0,0 +1,24 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!--  Copyright (C) 2020 The Android Open Source Project
+
+     Licensed under the Apache License, Version 2.0 (the "License");
+     you may not use this file except in compliance with the License.
+     You may obtain a copy of the License at
+
+          http://www.apache.org/licenses/LICENSE-2.0
+
+     Unless required by applicable law or agreed to in writing, software
+     distributed under the License is distributed on an "AS IS" BASIS,
+     WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+     See the License for the specific language governing permissions and
+     limitations under the License.
+ -->
+
+<resources xmlns:android="http://schemas.android.com/apk/res/android"
+    xmlns:xliff="urn:oasis:names:tc:xliff:document:1.2">
+    <string name="no_upstream_notification_title" msgid="5030042590486713460">"Verbinding het nie internet nie"</string>
+    <string name="no_upstream_notification_message" msgid="3843613362272973447">"Toestelle kan nie koppel nie"</string>
+    <string name="no_upstream_notification_disable_button" msgid="6385491461813507624">"Skakel verbinding af"</string>
+    <string name="upstream_roaming_notification_title" msgid="3015912166812283303">"Warmkol of verbinding is aan"</string>
+    <string name="upstream_roaming_notification_message" msgid="6724434706748439902">"Bykomende heffings kan geld terwyl jy swerf"</string>
+</resources>
diff --git a/Tethering/res/values-mcc310-mnc004-am/strings.xml b/Tethering/res/values-mcc310-mnc004-am/strings.xml
new file mode 100644
index 0000000..8995430
--- /dev/null
+++ b/Tethering/res/values-mcc310-mnc004-am/strings.xml
@@ -0,0 +1,24 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!--  Copyright (C) 2020 The Android Open Source Project
+
+     Licensed under the Apache License, Version 2.0 (the "License");
+     you may not use this file except in compliance with the License.
+     You may obtain a copy of the License at
+
+          http://www.apache.org/licenses/LICENSE-2.0
+
+     Unless required by applicable law or agreed to in writing, software
+     distributed under the License is distributed on an "AS IS" BASIS,
+     WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+     See the License for the specific language governing permissions and
+     limitations under the License.
+ -->
+
+<resources xmlns:android="http://schemas.android.com/apk/res/android"
+    xmlns:xliff="urn:oasis:names:tc:xliff:document:1.2">
+    <string name="no_upstream_notification_title" msgid="5030042590486713460">"ማስተሳሰር ምንም በይነመረብ የለውም"</string>
+    <string name="no_upstream_notification_message" msgid="3843613362272973447">"መሣሪያዎችን ማገናኘት አይቻልም"</string>
+    <string name="no_upstream_notification_disable_button" msgid="6385491461813507624">"ማስተሳሰርን አጥፋ"</string>
+    <string name="upstream_roaming_notification_title" msgid="3015912166812283303">"መገናኛ ነጥብ ወይም ማስተሳሰር በርቷል"</string>
+    <string name="upstream_roaming_notification_message" msgid="6724434706748439902">"በሚያንዣብብበት ጊዜ ተጨማሪ ክፍያዎች ተፈጻሚ ሊሆኑ ይችላሉ"</string>
+</resources>
diff --git a/Tethering/res/values-mcc310-mnc004-ar/strings.xml b/Tethering/res/values-mcc310-mnc004-ar/strings.xml
new file mode 100644
index 0000000..54f3b53
--- /dev/null
+++ b/Tethering/res/values-mcc310-mnc004-ar/strings.xml
@@ -0,0 +1,24 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!--  Copyright (C) 2020 The Android Open Source Project
+
+     Licensed under the Apache License, Version 2.0 (the "License");
+     you may not use this file except in compliance with the License.
+     You may obtain a copy of the License at
+
+          http://www.apache.org/licenses/LICENSE-2.0
+
+     Unless required by applicable law or agreed to in writing, software
+     distributed under the License is distributed on an "AS IS" BASIS,
+     WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+     See the License for the specific language governing permissions and
+     limitations under the License.
+ -->
+
+<resources xmlns:android="http://schemas.android.com/apk/res/android"
+    xmlns:xliff="urn:oasis:names:tc:xliff:document:1.2">
+    <string name="no_upstream_notification_title" msgid="5030042590486713460">"ما مِن اتصال بالإنترنت خلال التوصيل"</string>
+    <string name="no_upstream_notification_message" msgid="3843613362272973447">"تعذّر اتصال الأجهزة"</string>
+    <string name="no_upstream_notification_disable_button" msgid="6385491461813507624">"إيقاف التوصيل"</string>
+    <string name="upstream_roaming_notification_title" msgid="3015912166812283303">"نقطة الاتصال أو التوصيل مفعّلان"</string>
+    <string name="upstream_roaming_notification_message" msgid="6724434706748439902">"قد يتم تطبيق رسوم إضافية أثناء التجوال."</string>
+</resources>
diff --git a/Tethering/res/values-mcc310-mnc004-as/strings.xml b/Tethering/res/values-mcc310-mnc004-as/strings.xml
new file mode 100644
index 0000000..e215141
--- /dev/null
+++ b/Tethering/res/values-mcc310-mnc004-as/strings.xml
@@ -0,0 +1,24 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!--  Copyright (C) 2020 The Android Open Source Project
+
+     Licensed under the Apache License, Version 2.0 (the "License");
+     you may not use this file except in compliance with the License.
+     You may obtain a copy of the License at
+
+          http://www.apache.org/licenses/LICENSE-2.0
+
+     Unless required by applicable law or agreed to in writing, software
+     distributed under the License is distributed on an "AS IS" BASIS,
+     WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+     See the License for the specific language governing permissions and
+     limitations under the License.
+ -->
+
+<resources xmlns:android="http://schemas.android.com/apk/res/android"
+    xmlns:xliff="urn:oasis:names:tc:xliff:document:1.2">
+    <string name="no_upstream_notification_title" msgid="5030042590486713460">"টে\'ডাৰিঙৰ ইণ্টাৰনেট নাই"</string>
+    <string name="no_upstream_notification_message" msgid="3843613362272973447">"ডিভাইচসমূহ সংযোগ কৰিব নোৱাৰি"</string>
+    <string name="no_upstream_notification_disable_button" msgid="6385491461813507624">"টে\'ডাৰিং অফ কৰক"</string>
+    <string name="upstream_roaming_notification_title" msgid="3015912166812283303">"হটস্পট অথবা টে\'ডাৰিং অন আছে"</string>
+    <string name="upstream_roaming_notification_message" msgid="6724434706748439902">"ৰ\'মিঙত থাকিলে অতিৰিক্ত মাচুল প্ৰযোজ্য হ’ব পাৰে"</string>
+</resources>
diff --git a/Tethering/res/values-mcc310-mnc004-az/strings.xml b/Tethering/res/values-mcc310-mnc004-az/strings.xml
new file mode 100644
index 0000000..1fd8e4c
--- /dev/null
+++ b/Tethering/res/values-mcc310-mnc004-az/strings.xml
@@ -0,0 +1,24 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!--  Copyright (C) 2020 The Android Open Source Project
+
+     Licensed under the Apache License, Version 2.0 (the "License");
+     you may not use this file except in compliance with the License.
+     You may obtain a copy of the License at
+
+          http://www.apache.org/licenses/LICENSE-2.0
+
+     Unless required by applicable law or agreed to in writing, software
+     distributed under the License is distributed on an "AS IS" BASIS,
+     WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+     See the License for the specific language governing permissions and
+     limitations under the License.
+ -->
+
+<resources xmlns:android="http://schemas.android.com/apk/res/android"
+    xmlns:xliff="urn:oasis:names:tc:xliff:document:1.2">
+    <string name="no_upstream_notification_title" msgid="5030042590486713460">"Modemin internetə girişi yoxdur"</string>
+    <string name="no_upstream_notification_message" msgid="3843613362272973447">"Cihazları qoşmaq mümkün deyil"</string>
+    <string name="no_upstream_notification_disable_button" msgid="6385491461813507624">"Modemi deaktiv edin"</string>
+    <string name="upstream_roaming_notification_title" msgid="3015912166812283303">"Hotspot və ya modem aktivdir"</string>
+    <string name="upstream_roaming_notification_message" msgid="6724434706748439902">"Rouminq zamanı əlavə ödənişlər tətbiq edilə bilər"</string>
+</resources>
diff --git a/Tethering/res/values-mcc310-mnc004-b+sr+Latn/strings.xml b/Tethering/res/values-mcc310-mnc004-b+sr+Latn/strings.xml
new file mode 100644
index 0000000..1abe4f3
--- /dev/null
+++ b/Tethering/res/values-mcc310-mnc004-b+sr+Latn/strings.xml
@@ -0,0 +1,24 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!--  Copyright (C) 2020 The Android Open Source Project
+
+     Licensed under the Apache License, Version 2.0 (the "License");
+     you may not use this file except in compliance with the License.
+     You may obtain a copy of the License at
+
+          http://www.apache.org/licenses/LICENSE-2.0
+
+     Unless required by applicable law or agreed to in writing, software
+     distributed under the License is distributed on an "AS IS" BASIS,
+     WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+     See the License for the specific language governing permissions and
+     limitations under the License.
+ -->
+
+<resources xmlns:android="http://schemas.android.com/apk/res/android"
+    xmlns:xliff="urn:oasis:names:tc:xliff:document:1.2">
+    <string name="no_upstream_notification_title" msgid="5030042590486713460">"Privezivanje nema pristup internetu"</string>
+    <string name="no_upstream_notification_message" msgid="3843613362272973447">"Povezivanje uređaja nije uspelo"</string>
+    <string name="no_upstream_notification_disable_button" msgid="6385491461813507624">"Isključi privezivanje"</string>
+    <string name="upstream_roaming_notification_title" msgid="3015912166812283303">"Uključen je hotspot ili privezivanje"</string>
+    <string name="upstream_roaming_notification_message" msgid="6724434706748439902">"Možda važe dodatni troškovi u romingu"</string>
+</resources>
diff --git a/Tethering/res/values-mcc310-mnc004-be/strings.xml b/Tethering/res/values-mcc310-mnc004-be/strings.xml
new file mode 100644
index 0000000..38dbd1e
--- /dev/null
+++ b/Tethering/res/values-mcc310-mnc004-be/strings.xml
@@ -0,0 +1,24 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!--  Copyright (C) 2020 The Android Open Source Project
+
+     Licensed under the Apache License, Version 2.0 (the "License");
+     you may not use this file except in compliance with the License.
+     You may obtain a copy of the License at
+
+          http://www.apache.org/licenses/LICENSE-2.0
+
+     Unless required by applicable law or agreed to in writing, software
+     distributed under the License is distributed on an "AS IS" BASIS,
+     WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+     See the License for the specific language governing permissions and
+     limitations under the License.
+ -->
+
+<resources xmlns:android="http://schemas.android.com/apk/res/android"
+    xmlns:xliff="urn:oasis:names:tc:xliff:document:1.2">
+    <string name="no_upstream_notification_title" msgid="5030042590486713460">"Рэжым мадэма выкарыстоўваецца без доступу да інтэрнэту"</string>
+    <string name="no_upstream_notification_message" msgid="3843613362272973447">"Не ўдалося падключыць прылады"</string>
+    <string name="no_upstream_notification_disable_button" msgid="6385491461813507624">"Выключыць рэжым мадэма"</string>
+    <string name="upstream_roaming_notification_title" msgid="3015912166812283303">"Хот-спот або рэжым мадэма ўключаны"</string>
+    <string name="upstream_roaming_notification_message" msgid="6724434706748439902">"Пры выкарыстанні роўмінгу можа спаганяцца дадатковая плата"</string>
+</resources>
diff --git a/Tethering/res/values-mcc310-mnc004-bg/strings.xml b/Tethering/res/values-mcc310-mnc004-bg/strings.xml
new file mode 100644
index 0000000..04b44db
--- /dev/null
+++ b/Tethering/res/values-mcc310-mnc004-bg/strings.xml
@@ -0,0 +1,24 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!--  Copyright (C) 2020 The Android Open Source Project
+
+     Licensed under the Apache License, Version 2.0 (the "License");
+     you may not use this file except in compliance with the License.
+     You may obtain a copy of the License at
+
+          http://www.apache.org/licenses/LICENSE-2.0
+
+     Unless required by applicable law or agreed to in writing, software
+     distributed under the License is distributed on an "AS IS" BASIS,
+     WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+     See the License for the specific language governing permissions and
+     limitations under the License.
+ -->
+
+<resources xmlns:android="http://schemas.android.com/apk/res/android"
+    xmlns:xliff="urn:oasis:names:tc:xliff:document:1.2">
+    <string name="no_upstream_notification_title" msgid="5030042590486713460">"Тетърингът няма връзка с интернет"</string>
+    <string name="no_upstream_notification_message" msgid="3843613362272973447">"Устройствата не могат да установят връзка"</string>
+    <string name="no_upstream_notification_disable_button" msgid="6385491461813507624">"Изключване на тетъринга"</string>
+    <string name="upstream_roaming_notification_title" msgid="3015912166812283303">"Точката за достъп или тетърингът са включени"</string>
+    <string name="upstream_roaming_notification_message" msgid="6724434706748439902">"Възможно е да ви бъдат начислени допълнителни такси при роуминг"</string>
+</resources>
diff --git a/Tethering/res/values-mcc310-mnc004-bn/strings.xml b/Tethering/res/values-mcc310-mnc004-bn/strings.xml
new file mode 100644
index 0000000..579d1be
--- /dev/null
+++ b/Tethering/res/values-mcc310-mnc004-bn/strings.xml
@@ -0,0 +1,24 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!--  Copyright (C) 2020 The Android Open Source Project
+
+     Licensed under the Apache License, Version 2.0 (the "License");
+     you may not use this file except in compliance with the License.
+     You may obtain a copy of the License at
+
+          http://www.apache.org/licenses/LICENSE-2.0
+
+     Unless required by applicable law or agreed to in writing, software
+     distributed under the License is distributed on an "AS IS" BASIS,
+     WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+     See the License for the specific language governing permissions and
+     limitations under the License.
+ -->
+
+<resources xmlns:android="http://schemas.android.com/apk/res/android"
+    xmlns:xliff="urn:oasis:names:tc:xliff:document:1.2">
+    <string name="no_upstream_notification_title" msgid="5030042590486713460">"টিথারিং করার জন্য কোনও ইন্টারনেট কানেকশন নেই"</string>
+    <string name="no_upstream_notification_message" msgid="3843613362272973447">"ডিভাইস কানেক্ট করতে পারছে না"</string>
+    <string name="no_upstream_notification_disable_button" msgid="6385491461813507624">"টিথারিং বন্ধ করুন"</string>
+    <string name="upstream_roaming_notification_title" msgid="3015912166812283303">"হটস্পট বা টিথারিং চালু আছে"</string>
+    <string name="upstream_roaming_notification_message" msgid="6724434706748439902">"রোমিংয়ের সময় অতিরিক্ত চার্জ করা হতে পারে"</string>
+</resources>
diff --git a/Tethering/res/values-mcc310-mnc004-bs/strings.xml b/Tethering/res/values-mcc310-mnc004-bs/strings.xml
new file mode 100644
index 0000000..9ce3efe
--- /dev/null
+++ b/Tethering/res/values-mcc310-mnc004-bs/strings.xml
@@ -0,0 +1,24 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!--  Copyright (C) 2020 The Android Open Source Project
+
+     Licensed under the Apache License, Version 2.0 (the "License");
+     you may not use this file except in compliance with the License.
+     You may obtain a copy of the License at
+
+          http://www.apache.org/licenses/LICENSE-2.0
+
+     Unless required by applicable law or agreed to in writing, software
+     distributed under the License is distributed on an "AS IS" BASIS,
+     WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+     See the License for the specific language governing permissions and
+     limitations under the License.
+ -->
+
+<resources xmlns:android="http://schemas.android.com/apk/res/android"
+    xmlns:xliff="urn:oasis:names:tc:xliff:document:1.2">
+    <string name="no_upstream_notification_title" msgid="5030042590486713460">"Povezivanje putem mobitela nema internet"</string>
+    <string name="no_upstream_notification_message" msgid="3843613362272973447">"Uređaji se ne mogu povezati"</string>
+    <string name="no_upstream_notification_disable_button" msgid="6385491461813507624">"Isključi povezivanje putem mobitela"</string>
+    <string name="upstream_roaming_notification_title" msgid="3015912166812283303">"Pristupna tačka ili povezivanje putem mobitela je uključeno"</string>
+    <string name="upstream_roaming_notification_message" msgid="6724434706748439902">"Mogu nastati dodatni troškovi u romingu"</string>
+</resources>
diff --git a/Tethering/res/values-mcc310-mnc004-ca/strings.xml b/Tethering/res/values-mcc310-mnc004-ca/strings.xml
new file mode 100644
index 0000000..46d4c35
--- /dev/null
+++ b/Tethering/res/values-mcc310-mnc004-ca/strings.xml
@@ -0,0 +1,24 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!--  Copyright (C) 2020 The Android Open Source Project
+
+     Licensed under the Apache License, Version 2.0 (the "License");
+     you may not use this file except in compliance with the License.
+     You may obtain a copy of the License at
+
+          http://www.apache.org/licenses/LICENSE-2.0
+
+     Unless required by applicable law or agreed to in writing, software
+     distributed under the License is distributed on an "AS IS" BASIS,
+     WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+     See the License for the specific language governing permissions and
+     limitations under the License.
+ -->
+
+<resources xmlns:android="http://schemas.android.com/apk/res/android"
+    xmlns:xliff="urn:oasis:names:tc:xliff:document:1.2">
+    <string name="no_upstream_notification_title" msgid="5030042590486713460">"La compartició de xarxa no té accés a Internet"</string>
+    <string name="no_upstream_notification_message" msgid="3843613362272973447">"No es poden connectar els dispositius"</string>
+    <string name="no_upstream_notification_disable_button" msgid="6385491461813507624">"Desactiva la compartició de xarxa"</string>
+    <string name="upstream_roaming_notification_title" msgid="3015912166812283303">"S\'ha activat el punt d\'accés Wi‑Fi o la compartició de xarxa"</string>
+    <string name="upstream_roaming_notification_message" msgid="6724434706748439902">"És possible que s\'apliquin costos addicionals en itinerància"</string>
+</resources>
diff --git a/Tethering/res/values-mcc310-mnc004-cs/strings.xml b/Tethering/res/values-mcc310-mnc004-cs/strings.xml
new file mode 100644
index 0000000..cc13860
--- /dev/null
+++ b/Tethering/res/values-mcc310-mnc004-cs/strings.xml
@@ -0,0 +1,24 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!--  Copyright (C) 2020 The Android Open Source Project
+
+     Licensed under the Apache License, Version 2.0 (the "License");
+     you may not use this file except in compliance with the License.
+     You may obtain a copy of the License at
+
+          http://www.apache.org/licenses/LICENSE-2.0
+
+     Unless required by applicable law or agreed to in writing, software
+     distributed under the License is distributed on an "AS IS" BASIS,
+     WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+     See the License for the specific language governing permissions and
+     limitations under the License.
+ -->
+
+<resources xmlns:android="http://schemas.android.com/apk/res/android"
+    xmlns:xliff="urn:oasis:names:tc:xliff:document:1.2">
+    <string name="no_upstream_notification_title" msgid="5030042590486713460">"Tethering nemá připojení k internetu"</string>
+    <string name="no_upstream_notification_message" msgid="3843613362272973447">"Zařízení se nemůžou připojit"</string>
+    <string name="no_upstream_notification_disable_button" msgid="6385491461813507624">"Vypnout tethering"</string>
+    <string name="upstream_roaming_notification_title" msgid="3015912166812283303">"Je zapnutý hotspot nebo tethering"</string>
+    <string name="upstream_roaming_notification_message" msgid="6724434706748439902">"Při roamingu mohou být účtovány dodatečné poplatky"</string>
+</resources>
diff --git a/Tethering/res/values-mcc310-mnc004-da/strings.xml b/Tethering/res/values-mcc310-mnc004-da/strings.xml
new file mode 100644
index 0000000..92c3ae1
--- /dev/null
+++ b/Tethering/res/values-mcc310-mnc004-da/strings.xml
@@ -0,0 +1,24 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!--  Copyright (C) 2020 The Android Open Source Project
+
+     Licensed under the Apache License, Version 2.0 (the "License");
+     you may not use this file except in compliance with the License.
+     You may obtain a copy of the License at
+
+          http://www.apache.org/licenses/LICENSE-2.0
+
+     Unless required by applicable law or agreed to in writing, software
+     distributed under the License is distributed on an "AS IS" BASIS,
+     WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+     See the License for the specific language governing permissions and
+     limitations under the License.
+ -->
+
+<resources xmlns:android="http://schemas.android.com/apk/res/android"
+    xmlns:xliff="urn:oasis:names:tc:xliff:document:1.2">
+    <string name="no_upstream_notification_title" msgid="5030042590486713460">"Netdeling har ingen internetforbindelse"</string>
+    <string name="no_upstream_notification_message" msgid="3843613362272973447">"Enheder kan ikke oprette forbindelse"</string>
+    <string name="no_upstream_notification_disable_button" msgid="6385491461813507624">"Deaktiver netdeling"</string>
+    <string name="upstream_roaming_notification_title" msgid="3015912166812283303">"Hotspot eller netdeling er aktiveret"</string>
+    <string name="upstream_roaming_notification_message" msgid="6724434706748439902">"Der opkræves muligvis yderligere gebyrer ved roaming"</string>
+</resources>
diff --git a/Tethering/res/values-mcc310-mnc004-de/strings.xml b/Tethering/res/values-mcc310-mnc004-de/strings.xml
new file mode 100644
index 0000000..967eb4d
--- /dev/null
+++ b/Tethering/res/values-mcc310-mnc004-de/strings.xml
@@ -0,0 +1,24 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!--  Copyright (C) 2020 The Android Open Source Project
+
+     Licensed under the Apache License, Version 2.0 (the "License");
+     you may not use this file except in compliance with the License.
+     You may obtain a copy of the License at
+
+          http://www.apache.org/licenses/LICENSE-2.0
+
+     Unless required by applicable law or agreed to in writing, software
+     distributed under the License is distributed on an "AS IS" BASIS,
+     WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+     See the License for the specific language governing permissions and
+     limitations under the License.
+ -->
+
+<resources xmlns:android="http://schemas.android.com/apk/res/android"
+    xmlns:xliff="urn:oasis:names:tc:xliff:document:1.2">
+    <string name="no_upstream_notification_title" msgid="5030042590486713460">"Tethering hat keinen Internetzugriff"</string>
+    <string name="no_upstream_notification_message" msgid="3843613362272973447">"Geräte können sich nicht verbinden"</string>
+    <string name="no_upstream_notification_disable_button" msgid="6385491461813507624">"Tethering deaktivieren"</string>
+    <string name="upstream_roaming_notification_title" msgid="3015912166812283303">"Hotspot oder Tethering ist aktiviert"</string>
+    <string name="upstream_roaming_notification_message" msgid="6724434706748439902">"Für das Roaming können zusätzliche Gebühren anfallen"</string>
+</resources>
diff --git a/Tethering/res/values-mcc310-mnc004-el/strings.xml b/Tethering/res/values-mcc310-mnc004-el/strings.xml
new file mode 100644
index 0000000..5fb4974
--- /dev/null
+++ b/Tethering/res/values-mcc310-mnc004-el/strings.xml
@@ -0,0 +1,24 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!--  Copyright (C) 2020 The Android Open Source Project
+
+     Licensed under the Apache License, Version 2.0 (the "License");
+     you may not use this file except in compliance with the License.
+     You may obtain a copy of the License at
+
+          http://www.apache.org/licenses/LICENSE-2.0
+
+     Unless required by applicable law or agreed to in writing, software
+     distributed under the License is distributed on an "AS IS" BASIS,
+     WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+     See the License for the specific language governing permissions and
+     limitations under the License.
+ -->
+
+<resources xmlns:android="http://schemas.android.com/apk/res/android"
+    xmlns:xliff="urn:oasis:names:tc:xliff:document:1.2">
+    <string name="no_upstream_notification_title" msgid="5030042590486713460">"Η σύνδεση δεν έχει πρόσβαση στο διαδίκτυο"</string>
+    <string name="no_upstream_notification_message" msgid="3843613362272973447">"Δεν είναι δυνατή η σύνδεση των συσκευών"</string>
+    <string name="no_upstream_notification_disable_button" msgid="6385491461813507624">"Απενεργοποιήστε τη σύνδεση"</string>
+    <string name="upstream_roaming_notification_title" msgid="3015912166812283303">"Ενεργό σημείο πρόσβασης Wi-Fi ή ενεργή σύνδεση"</string>
+    <string name="upstream_roaming_notification_message" msgid="6724434706748439902">"Ενδέχεται να ισχύουν επιπλέον χρεώσεις κατά την περιαγωγή."</string>
+</resources>
diff --git a/Tethering/res/values-mcc310-mnc004-en-rAU/strings.xml b/Tethering/res/values-mcc310-mnc004-en-rAU/strings.xml
new file mode 100644
index 0000000..45647f9
--- /dev/null
+++ b/Tethering/res/values-mcc310-mnc004-en-rAU/strings.xml
@@ -0,0 +1,24 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!--  Copyright (C) 2020 The Android Open Source Project
+
+     Licensed under the Apache License, Version 2.0 (the "License");
+     you may not use this file except in compliance with the License.
+     You may obtain a copy of the License at
+
+          http://www.apache.org/licenses/LICENSE-2.0
+
+     Unless required by applicable law or agreed to in writing, software
+     distributed under the License is distributed on an "AS IS" BASIS,
+     WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+     See the License for the specific language governing permissions and
+     limitations under the License.
+ -->
+
+<resources xmlns:android="http://schemas.android.com/apk/res/android"
+    xmlns:xliff="urn:oasis:names:tc:xliff:document:1.2">
+    <string name="no_upstream_notification_title" msgid="5030042590486713460">"Tethering has no Internet"</string>
+    <string name="no_upstream_notification_message" msgid="3843613362272973447">"Devices can’t connect"</string>
+    <string name="no_upstream_notification_disable_button" msgid="6385491461813507624">"Turn off tethering"</string>
+    <string name="upstream_roaming_notification_title" msgid="3015912166812283303">"Hotspot or tethering is on"</string>
+    <string name="upstream_roaming_notification_message" msgid="6724434706748439902">"Additional charges may apply while roaming"</string>
+</resources>
diff --git a/Tethering/res/values-mcc310-mnc004-en-rCA/strings.xml b/Tethering/res/values-mcc310-mnc004-en-rCA/strings.xml
new file mode 100644
index 0000000..45647f9
--- /dev/null
+++ b/Tethering/res/values-mcc310-mnc004-en-rCA/strings.xml
@@ -0,0 +1,24 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!--  Copyright (C) 2020 The Android Open Source Project
+
+     Licensed under the Apache License, Version 2.0 (the "License");
+     you may not use this file except in compliance with the License.
+     You may obtain a copy of the License at
+
+          http://www.apache.org/licenses/LICENSE-2.0
+
+     Unless required by applicable law or agreed to in writing, software
+     distributed under the License is distributed on an "AS IS" BASIS,
+     WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+     See the License for the specific language governing permissions and
+     limitations under the License.
+ -->
+
+<resources xmlns:android="http://schemas.android.com/apk/res/android"
+    xmlns:xliff="urn:oasis:names:tc:xliff:document:1.2">
+    <string name="no_upstream_notification_title" msgid="5030042590486713460">"Tethering has no Internet"</string>
+    <string name="no_upstream_notification_message" msgid="3843613362272973447">"Devices can’t connect"</string>
+    <string name="no_upstream_notification_disable_button" msgid="6385491461813507624">"Turn off tethering"</string>
+    <string name="upstream_roaming_notification_title" msgid="3015912166812283303">"Hotspot or tethering is on"</string>
+    <string name="upstream_roaming_notification_message" msgid="6724434706748439902">"Additional charges may apply while roaming"</string>
+</resources>
diff --git a/Tethering/res/values-mcc310-mnc004-en-rGB/strings.xml b/Tethering/res/values-mcc310-mnc004-en-rGB/strings.xml
new file mode 100644
index 0000000..45647f9
--- /dev/null
+++ b/Tethering/res/values-mcc310-mnc004-en-rGB/strings.xml
@@ -0,0 +1,24 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!--  Copyright (C) 2020 The Android Open Source Project
+
+     Licensed under the Apache License, Version 2.0 (the "License");
+     you may not use this file except in compliance with the License.
+     You may obtain a copy of the License at
+
+          http://www.apache.org/licenses/LICENSE-2.0
+
+     Unless required by applicable law or agreed to in writing, software
+     distributed under the License is distributed on an "AS IS" BASIS,
+     WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+     See the License for the specific language governing permissions and
+     limitations under the License.
+ -->
+
+<resources xmlns:android="http://schemas.android.com/apk/res/android"
+    xmlns:xliff="urn:oasis:names:tc:xliff:document:1.2">
+    <string name="no_upstream_notification_title" msgid="5030042590486713460">"Tethering has no Internet"</string>
+    <string name="no_upstream_notification_message" msgid="3843613362272973447">"Devices can’t connect"</string>
+    <string name="no_upstream_notification_disable_button" msgid="6385491461813507624">"Turn off tethering"</string>
+    <string name="upstream_roaming_notification_title" msgid="3015912166812283303">"Hotspot or tethering is on"</string>
+    <string name="upstream_roaming_notification_message" msgid="6724434706748439902">"Additional charges may apply while roaming"</string>
+</resources>
diff --git a/Tethering/res/values-mcc310-mnc004-en-rIN/strings.xml b/Tethering/res/values-mcc310-mnc004-en-rIN/strings.xml
new file mode 100644
index 0000000..45647f9
--- /dev/null
+++ b/Tethering/res/values-mcc310-mnc004-en-rIN/strings.xml
@@ -0,0 +1,24 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!--  Copyright (C) 2020 The Android Open Source Project
+
+     Licensed under the Apache License, Version 2.0 (the "License");
+     you may not use this file except in compliance with the License.
+     You may obtain a copy of the License at
+
+          http://www.apache.org/licenses/LICENSE-2.0
+
+     Unless required by applicable law or agreed to in writing, software
+     distributed under the License is distributed on an "AS IS" BASIS,
+     WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+     See the License for the specific language governing permissions and
+     limitations under the License.
+ -->
+
+<resources xmlns:android="http://schemas.android.com/apk/res/android"
+    xmlns:xliff="urn:oasis:names:tc:xliff:document:1.2">
+    <string name="no_upstream_notification_title" msgid="5030042590486713460">"Tethering has no Internet"</string>
+    <string name="no_upstream_notification_message" msgid="3843613362272973447">"Devices can’t connect"</string>
+    <string name="no_upstream_notification_disable_button" msgid="6385491461813507624">"Turn off tethering"</string>
+    <string name="upstream_roaming_notification_title" msgid="3015912166812283303">"Hotspot or tethering is on"</string>
+    <string name="upstream_roaming_notification_message" msgid="6724434706748439902">"Additional charges may apply while roaming"</string>
+</resources>
diff --git a/Tethering/res/values-mcc310-mnc004-en-rXC/strings.xml b/Tethering/res/values-mcc310-mnc004-en-rXC/strings.xml
new file mode 100644
index 0000000..7877074
--- /dev/null
+++ b/Tethering/res/values-mcc310-mnc004-en-rXC/strings.xml
@@ -0,0 +1,24 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!--  Copyright (C) 2020 The Android Open Source Project
+
+     Licensed under the Apache License, Version 2.0 (the "License");
+     you may not use this file except in compliance with the License.
+     You may obtain a copy of the License at
+
+          http://www.apache.org/licenses/LICENSE-2.0
+
+     Unless required by applicable law or agreed to in writing, software
+     distributed under the License is distributed on an "AS IS" BASIS,
+     WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+     See the License for the specific language governing permissions and
+     limitations under the License.
+ -->
+
+<resources xmlns:android="http://schemas.android.com/apk/res/android"
+    xmlns:xliff="urn:oasis:names:tc:xliff:document:1.2">
+    <string name="no_upstream_notification_title" msgid="5030042590486713460">"‎‏‎‎‎‎‎‏‎‏‏‏‎‎‎‎‎‎‏‎‎‏‎‎‎‎‏‏‏‏‏‏‏‏‎‎‎‏‎‏‏‏‎‎‏‏‏‎‎‏‎‎‏‏‎‏‎‎‎‏‎‏‎‏‏‏‏‏‎‎‏‏‎‎‎‎‏‎‏‏‏‏‎‏‎‏‎‎‎‏‏‏‎‏‎‎‎Tethering has no internet‎‏‎‎‏‎"</string>
+    <string name="no_upstream_notification_message" msgid="3843613362272973447">"‎‏‎‎‎‎‎‏‎‏‏‏‎‎‎‎‎‎‏‎‎‏‎‎‎‎‏‏‏‏‏‏‎‏‏‎‏‎‏‎‏‎‏‎‏‏‏‎‏‎‎‎‎‎‏‏‏‏‏‏‏‎‏‎‎‎‏‏‎‎‎‎‎‏‏‏‎‎‏‏‎‏‏‎‎‏‎‏‎‎‎‎‏‏‏‎Devices can’t connect‎‏‎‎‏‎"</string>
+    <string name="no_upstream_notification_disable_button" msgid="6385491461813507624">"‎‏‎‎‎‎‎‏‎‏‏‏‎‎‎‎‎‎‏‎‎‏‎‎‎‎‏‏‏‏‏‏‏‏‎‏‏‎‎‎‏‎‎‏‏‏‎‏‏‏‎‏‎‎‏‎‏‎‏‎‎‏‏‏‎‎‎‏‏‎‎‏‏‎‏‎‏‏‏‏‎‎‎‏‎‏‏‎‎‎‏‎‏‎‎‎‎Turn off tethering‎‏‎‎‏‎"</string>
+    <string name="upstream_roaming_notification_title" msgid="3015912166812283303">"‎‏‎‎‎‎‎‏‎‏‏‏‎‎‎‎‎‎‏‎‎‏‎‎‎‎‏‏‏‏‏‏‎‏‎‏‎‎‏‏‏‎‏‏‎‏‎‏‎‏‎‏‏‎‎‎‎‏‎‎‎‏‏‎‎‎‎‎‎‎‎‏‎‎‏‏‏‏‏‏‏‏‏‎‎‎‏‏‎‏‎‎‏‏‏‎Hotspot or tethering is on‎‏‎‎‏‎"</string>
+    <string name="upstream_roaming_notification_message" msgid="6724434706748439902">"‎‏‎‎‎‎‎‏‎‏‏‏‎‎‎‎‎‎‏‎‎‏‎‎‎‎‏‏‏‏‏‏‏‏‎‏‏‏‎‏‎‏‎‏‎‎‎‏‏‏‏‏‏‏‎‏‏‎‏‏‏‏‎‎‏‏‏‏‏‎‏‏‎‎‎‎‏‏‎‎‎‏‏‏‏‏‎‏‎‏‎‏‏‏‏‎‎Additional charges may apply while roaming‎‏‎‎‏‎"</string>
+</resources>
diff --git a/Tethering/res/values-mcc310-mnc004-es-rUS/strings.xml b/Tethering/res/values-mcc310-mnc004-es-rUS/strings.xml
new file mode 100644
index 0000000..08edd81
--- /dev/null
+++ b/Tethering/res/values-mcc310-mnc004-es-rUS/strings.xml
@@ -0,0 +1,24 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!--  Copyright (C) 2020 The Android Open Source Project
+
+     Licensed under the Apache License, Version 2.0 (the "License");
+     you may not use this file except in compliance with the License.
+     You may obtain a copy of the License at
+
+          http://www.apache.org/licenses/LICENSE-2.0
+
+     Unless required by applicable law or agreed to in writing, software
+     distributed under the License is distributed on an "AS IS" BASIS,
+     WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+     See the License for the specific language governing permissions and
+     limitations under the License.
+ -->
+
+<resources xmlns:android="http://schemas.android.com/apk/res/android"
+    xmlns:xliff="urn:oasis:names:tc:xliff:document:1.2">
+    <string name="no_upstream_notification_title" msgid="5030042590486713460">"La conexión mediante dispositivo móvil no tiene Internet"</string>
+    <string name="no_upstream_notification_message" msgid="3843613362272973447">"No se pueden conectar los dispositivos"</string>
+    <string name="no_upstream_notification_disable_button" msgid="6385491461813507624">"Desactivar conexión mediante dispositivo móvil"</string>
+    <string name="upstream_roaming_notification_title" msgid="3015912166812283303">"Se activó el hotspot o la conexión mediante dispositivo móvil"</string>
+    <string name="upstream_roaming_notification_message" msgid="6724434706748439902">"Es posible que se apliquen cargos adicionales por roaming"</string>
+</resources>
diff --git a/Tethering/res/values-mcc310-mnc004-es/strings.xml b/Tethering/res/values-mcc310-mnc004-es/strings.xml
new file mode 100644
index 0000000..79f51d0
--- /dev/null
+++ b/Tethering/res/values-mcc310-mnc004-es/strings.xml
@@ -0,0 +1,24 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!--  Copyright (C) 2020 The Android Open Source Project
+
+     Licensed under the Apache License, Version 2.0 (the "License");
+     you may not use this file except in compliance with the License.
+     You may obtain a copy of the License at
+
+          http://www.apache.org/licenses/LICENSE-2.0
+
+     Unless required by applicable law or agreed to in writing, software
+     distributed under the License is distributed on an "AS IS" BASIS,
+     WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+     See the License for the specific language governing permissions and
+     limitations under the License.
+ -->
+
+<resources xmlns:android="http://schemas.android.com/apk/res/android"
+    xmlns:xliff="urn:oasis:names:tc:xliff:document:1.2">
+    <string name="no_upstream_notification_title" msgid="5030042590486713460">"La conexión no se puede compartir, porque no hay acceso a Internet"</string>
+    <string name="no_upstream_notification_message" msgid="3843613362272973447">"Los dispositivos no se pueden conectar"</string>
+    <string name="no_upstream_notification_disable_button" msgid="6385491461813507624">"Desactivar conexión compartida"</string>
+    <string name="upstream_roaming_notification_title" msgid="3015912166812283303">"Punto de acceso o conexión compartida activados"</string>
+    <string name="upstream_roaming_notification_message" msgid="6724434706748439902">"Puede que se apliquen cargos adicionales en itinerancia"</string>
+</resources>
diff --git a/Tethering/res/values-mcc310-mnc004-et/strings.xml b/Tethering/res/values-mcc310-mnc004-et/strings.xml
new file mode 100644
index 0000000..2da5f8a
--- /dev/null
+++ b/Tethering/res/values-mcc310-mnc004-et/strings.xml
@@ -0,0 +1,24 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!--  Copyright (C) 2020 The Android Open Source Project
+
+     Licensed under the Apache License, Version 2.0 (the "License");
+     you may not use this file except in compliance with the License.
+     You may obtain a copy of the License at
+
+          http://www.apache.org/licenses/LICENSE-2.0
+
+     Unless required by applicable law or agreed to in writing, software
+     distributed under the License is distributed on an "AS IS" BASIS,
+     WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+     See the License for the specific language governing permissions and
+     limitations under the License.
+ -->
+
+<resources xmlns:android="http://schemas.android.com/apk/res/android"
+    xmlns:xliff="urn:oasis:names:tc:xliff:document:1.2">
+    <string name="no_upstream_notification_title" msgid="5030042590486713460">"Jagamisel puudub internetiühendus"</string>
+    <string name="no_upstream_notification_message" msgid="3843613362272973447">"Seadmed ei saa ühendust luua"</string>
+    <string name="no_upstream_notification_disable_button" msgid="6385491461813507624">"Lülita jagamine välja"</string>
+    <string name="upstream_roaming_notification_title" msgid="3015912166812283303">"Kuumkoht või jagamine on sisse lülitatud"</string>
+    <string name="upstream_roaming_notification_message" msgid="6724434706748439902">"Rändluse kasutamisega võivad kaasneda lisatasud"</string>
+</resources>
diff --git a/Tethering/res/values-mcc310-mnc004-eu/strings.xml b/Tethering/res/values-mcc310-mnc004-eu/strings.xml
new file mode 100644
index 0000000..2073f28
--- /dev/null
+++ b/Tethering/res/values-mcc310-mnc004-eu/strings.xml
@@ -0,0 +1,24 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!--  Copyright (C) 2020 The Android Open Source Project
+
+     Licensed under the Apache License, Version 2.0 (the "License");
+     you may not use this file except in compliance with the License.
+     You may obtain a copy of the License at
+
+          http://www.apache.org/licenses/LICENSE-2.0
+
+     Unless required by applicable law or agreed to in writing, software
+     distributed under the License is distributed on an "AS IS" BASIS,
+     WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+     See the License for the specific language governing permissions and
+     limitations under the License.
+ -->
+
+<resources xmlns:android="http://schemas.android.com/apk/res/android"
+    xmlns:xliff="urn:oasis:names:tc:xliff:document:1.2">
+    <string name="no_upstream_notification_title" msgid="5030042590486713460">"Konexioa partekatzeko aukerak ez du Interneteko konexiorik"</string>
+    <string name="no_upstream_notification_message" msgid="3843613362272973447">"Ezin dira konektatu gailuak"</string>
+    <string name="no_upstream_notification_disable_button" msgid="6385491461813507624">"Desaktibatu konexioa partekatzeko aukera"</string>
+    <string name="upstream_roaming_notification_title" msgid="3015912166812283303">"Wifi-gunea edo konexioa partekatzeko aukera aktibatuta dago"</string>
+    <string name="upstream_roaming_notification_message" msgid="6724434706748439902">"Baliteke kostu gehigarriak ordaindu behar izatea ibiltaritzan"</string>
+</resources>
diff --git a/Tethering/res/values-mcc310-mnc004-fa/strings.xml b/Tethering/res/values-mcc310-mnc004-fa/strings.xml
new file mode 100644
index 0000000..e21b2a0
--- /dev/null
+++ b/Tethering/res/values-mcc310-mnc004-fa/strings.xml
@@ -0,0 +1,24 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!--  Copyright (C) 2020 The Android Open Source Project
+
+     Licensed under the Apache License, Version 2.0 (the "License");
+     you may not use this file except in compliance with the License.
+     You may obtain a copy of the License at
+
+          http://www.apache.org/licenses/LICENSE-2.0
+
+     Unless required by applicable law or agreed to in writing, software
+     distributed under the License is distributed on an "AS IS" BASIS,
+     WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+     See the License for the specific language governing permissions and
+     limitations under the License.
+ -->
+
+<resources xmlns:android="http://schemas.android.com/apk/res/android"
+    xmlns:xliff="urn:oasis:names:tc:xliff:document:1.2">
+    <string name="no_upstream_notification_title" msgid="5030042590486713460">"«اشتراک‌گذاری اینترنت» به اینترنت دسترسی ندارد"</string>
+    <string name="no_upstream_notification_message" msgid="3843613362272973447">"دستگاه‌ها متصل نمی‌شوند"</string>
+    <string name="no_upstream_notification_disable_button" msgid="6385491461813507624">"خاموش کردن «اشتراک‌گذاری اینترنت»"</string>
+    <string name="upstream_roaming_notification_title" msgid="3015912166812283303">"«نقطه اتصال» یا «اشتراک‌گذاری اینترنت» روشن است"</string>
+    <string name="upstream_roaming_notification_message" msgid="6724434706748439902">"ممکن است درحین فراگردی تغییرات دیگر اعمال شود"</string>
+</resources>
diff --git a/Tethering/res/values-mcc310-mnc004-fi/strings.xml b/Tethering/res/values-mcc310-mnc004-fi/strings.xml
new file mode 100644
index 0000000..88b0b13
--- /dev/null
+++ b/Tethering/res/values-mcc310-mnc004-fi/strings.xml
@@ -0,0 +1,24 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!--  Copyright (C) 2020 The Android Open Source Project
+
+     Licensed under the Apache License, Version 2.0 (the "License");
+     you may not use this file except in compliance with the License.
+     You may obtain a copy of the License at
+
+          http://www.apache.org/licenses/LICENSE-2.0
+
+     Unless required by applicable law or agreed to in writing, software
+     distributed under the License is distributed on an "AS IS" BASIS,
+     WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+     See the License for the specific language governing permissions and
+     limitations under the License.
+ -->
+
+<resources xmlns:android="http://schemas.android.com/apk/res/android"
+    xmlns:xliff="urn:oasis:names:tc:xliff:document:1.2">
+    <string name="no_upstream_notification_title" msgid="5030042590486713460">"Ei jaettavaa internetyhteyttä"</string>
+    <string name="no_upstream_notification_message" msgid="3843613362272973447">"Laitteet eivät voi muodostaa yhteyttä"</string>
+    <string name="no_upstream_notification_disable_button" msgid="6385491461813507624">"Laita yhteyden jakaminen pois päältä"</string>
+    <string name="upstream_roaming_notification_title" msgid="3015912166812283303">"Hotspot tai yhteyden jakaminen on päällä"</string>
+    <string name="upstream_roaming_notification_message" msgid="6724434706748439902">"Roaming voi aiheuttaa lisämaksuja"</string>
+</resources>
diff --git a/Tethering/res/values-mcc310-mnc004-fr-rCA/strings.xml b/Tethering/res/values-mcc310-mnc004-fr-rCA/strings.xml
new file mode 100644
index 0000000..3b781bc
--- /dev/null
+++ b/Tethering/res/values-mcc310-mnc004-fr-rCA/strings.xml
@@ -0,0 +1,24 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!--  Copyright (C) 2020 The Android Open Source Project
+
+     Licensed under the Apache License, Version 2.0 (the "License");
+     you may not use this file except in compliance with the License.
+     You may obtain a copy of the License at
+
+          http://www.apache.org/licenses/LICENSE-2.0
+
+     Unless required by applicable law or agreed to in writing, software
+     distributed under the License is distributed on an "AS IS" BASIS,
+     WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+     See the License for the specific language governing permissions and
+     limitations under the License.
+ -->
+
+<resources xmlns:android="http://schemas.android.com/apk/res/android"
+    xmlns:xliff="urn:oasis:names:tc:xliff:document:1.2">
+    <string name="no_upstream_notification_title" msgid="5030042590486713460">"Le partage de connexion n\'est pas connecté à Internet"</string>
+    <string name="no_upstream_notification_message" msgid="3843613362272973447">"Impossible de connecter les appareils"</string>
+    <string name="no_upstream_notification_disable_button" msgid="6385491461813507624">"Désactiver le partage de connexion"</string>
+    <string name="upstream_roaming_notification_title" msgid="3015912166812283303">"Le point d\'accès ou le partage de connexion est activé"</string>
+    <string name="upstream_roaming_notification_message" msgid="6724434706748439902">"En itinérance, des frais supplémentaires peuvent s\'appliquer"</string>
+</resources>
diff --git a/Tethering/res/values-mcc310-mnc004-fr/strings.xml b/Tethering/res/values-mcc310-mnc004-fr/strings.xml
new file mode 100644
index 0000000..51d7203
--- /dev/null
+++ b/Tethering/res/values-mcc310-mnc004-fr/strings.xml
@@ -0,0 +1,24 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!--  Copyright (C) 2020 The Android Open Source Project
+
+     Licensed under the Apache License, Version 2.0 (the "License");
+     you may not use this file except in compliance with the License.
+     You may obtain a copy of the License at
+
+          http://www.apache.org/licenses/LICENSE-2.0
+
+     Unless required by applicable law or agreed to in writing, software
+     distributed under the License is distributed on an "AS IS" BASIS,
+     WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+     See the License for the specific language governing permissions and
+     limitations under the License.
+ -->
+
+<resources xmlns:android="http://schemas.android.com/apk/res/android"
+    xmlns:xliff="urn:oasis:names:tc:xliff:document:1.2">
+    <string name="no_upstream_notification_title" msgid="5030042590486713460">"Aucune connexion à Internet n\'est disponible pour le partage de connexion"</string>
+    <string name="no_upstream_notification_message" msgid="3843613362272973447">"Impossible de connecter les appareils"</string>
+    <string name="no_upstream_notification_disable_button" msgid="6385491461813507624">"Désactiver le partage de connexion"</string>
+    <string name="upstream_roaming_notification_title" msgid="3015912166812283303">"Le point d\'accès ou le partage de connexion est activé"</string>
+    <string name="upstream_roaming_notification_message" msgid="6724434706748439902">"En itinérance, des frais supplémentaires peuvent s\'appliquer"</string>
+</resources>
diff --git a/Tethering/res/values-mcc310-mnc004-gl/strings.xml b/Tethering/res/values-mcc310-mnc004-gl/strings.xml
new file mode 100644
index 0000000..008ccb4
--- /dev/null
+++ b/Tethering/res/values-mcc310-mnc004-gl/strings.xml
@@ -0,0 +1,24 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!--  Copyright (C) 2020 The Android Open Source Project
+
+     Licensed under the Apache License, Version 2.0 (the "License");
+     you may not use this file except in compliance with the License.
+     You may obtain a copy of the License at
+
+          http://www.apache.org/licenses/LICENSE-2.0
+
+     Unless required by applicable law or agreed to in writing, software
+     distributed under the License is distributed on an "AS IS" BASIS,
+     WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+     See the License for the specific language governing permissions and
+     limitations under the License.
+ -->
+
+<resources xmlns:android="http://schemas.android.com/apk/res/android"
+    xmlns:xliff="urn:oasis:names:tc:xliff:document:1.2">
+    <string name="no_upstream_notification_title" msgid="5030042590486713460">"A conexión compartida non ten Internet"</string>
+    <string name="no_upstream_notification_message" msgid="3843613362272973447">"Non se puideron conectar os dispositivos"</string>
+    <string name="no_upstream_notification_disable_button" msgid="6385491461813507624">"Desactivar conexión compartida"</string>
+    <string name="upstream_roaming_notification_title" msgid="3015912166812283303">"Está activada a zona wifi ou a conexión compartida"</string>
+    <string name="upstream_roaming_notification_message" msgid="6724434706748439902">"Pódense aplicar cargos adicionais en itinerancia"</string>
+</resources>
diff --git a/Tethering/res/values-mcc310-mnc004-gu/strings.xml b/Tethering/res/values-mcc310-mnc004-gu/strings.xml
new file mode 100644
index 0000000..f2e3b4d
--- /dev/null
+++ b/Tethering/res/values-mcc310-mnc004-gu/strings.xml
@@ -0,0 +1,24 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!--  Copyright (C) 2020 The Android Open Source Project
+
+     Licensed under the Apache License, Version 2.0 (the "License");
+     you may not use this file except in compliance with the License.
+     You may obtain a copy of the License at
+
+          http://www.apache.org/licenses/LICENSE-2.0
+
+     Unless required by applicable law or agreed to in writing, software
+     distributed under the License is distributed on an "AS IS" BASIS,
+     WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+     See the License for the specific language governing permissions and
+     limitations under the License.
+ -->
+
+<resources xmlns:android="http://schemas.android.com/apk/res/android"
+    xmlns:xliff="urn:oasis:names:tc:xliff:document:1.2">
+    <string name="no_upstream_notification_title" msgid="5030042590486713460">"ઇન્ટરનેટ શેર કરવાની સુવિધામાં ઇન્ટરનેટ નથી"</string>
+    <string name="no_upstream_notification_message" msgid="3843613362272973447">"ડિવાઇસ કનેક્ટ કરી શકાતા નથી"</string>
+    <string name="no_upstream_notification_disable_button" msgid="6385491461813507624">"ઇન્ટરનેટ શેર કરવાની સુવિધા બંધ કરો"</string>
+    <string name="upstream_roaming_notification_title" msgid="3015912166812283303">"હૉટસ્પૉટ અથવા ઇન્ટરનેટ શેર કરવાની સુવિધા ચાલુ છે"</string>
+    <string name="upstream_roaming_notification_message" msgid="6724434706748439902">"રોમિંગમાં વધારાના શુલ્ક લાગી શકે છે"</string>
+</resources>
diff --git a/Tethering/res/values-mcc310-mnc004-hi/strings.xml b/Tethering/res/values-mcc310-mnc004-hi/strings.xml
new file mode 100644
index 0000000..b11839d
--- /dev/null
+++ b/Tethering/res/values-mcc310-mnc004-hi/strings.xml
@@ -0,0 +1,24 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!--  Copyright (C) 2020 The Android Open Source Project
+
+     Licensed under the Apache License, Version 2.0 (the "License");
+     you may not use this file except in compliance with the License.
+     You may obtain a copy of the License at
+
+          http://www.apache.org/licenses/LICENSE-2.0
+
+     Unless required by applicable law or agreed to in writing, software
+     distributed under the License is distributed on an "AS IS" BASIS,
+     WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+     See the License for the specific language governing permissions and
+     limitations under the License.
+ -->
+
+<resources xmlns:android="http://schemas.android.com/apk/res/android"
+    xmlns:xliff="urn:oasis:names:tc:xliff:document:1.2">
+    <string name="no_upstream_notification_title" msgid="5030042590486713460">"टेदरिंग से इंटरनेट नहीं चल रहा"</string>
+    <string name="no_upstream_notification_message" msgid="3843613362272973447">"डिवाइस कनेक्ट नहीं हो पा रहे"</string>
+    <string name="no_upstream_notification_disable_button" msgid="6385491461813507624">"टेदरिंग बंद करें"</string>
+    <string name="upstream_roaming_notification_title" msgid="3015912166812283303">"हॉटस्पॉट या टेदरिंग चालू है"</string>
+    <string name="upstream_roaming_notification_message" msgid="6724434706748439902">"रोमिंग के दौरान अतिरिक्त शुल्क लग सकता है"</string>
+</resources>
diff --git a/Tethering/res/values-mcc310-mnc004-hr/strings.xml b/Tethering/res/values-mcc310-mnc004-hr/strings.xml
new file mode 100644
index 0000000..0a5aca2
--- /dev/null
+++ b/Tethering/res/values-mcc310-mnc004-hr/strings.xml
@@ -0,0 +1,24 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!--  Copyright (C) 2020 The Android Open Source Project
+
+     Licensed under the Apache License, Version 2.0 (the "License");
+     you may not use this file except in compliance with the License.
+     You may obtain a copy of the License at
+
+          http://www.apache.org/licenses/LICENSE-2.0
+
+     Unless required by applicable law or agreed to in writing, software
+     distributed under the License is distributed on an "AS IS" BASIS,
+     WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+     See the License for the specific language governing permissions and
+     limitations under the License.
+ -->
+
+<resources xmlns:android="http://schemas.android.com/apk/res/android"
+    xmlns:xliff="urn:oasis:names:tc:xliff:document:1.2">
+    <string name="no_upstream_notification_title" msgid="5030042590486713460">"Modemsko povezivanje nema internet"</string>
+    <string name="no_upstream_notification_message" msgid="3843613362272973447">"Uređaji se ne mogu povezati"</string>
+    <string name="no_upstream_notification_disable_button" msgid="6385491461813507624">"Isključivanje modemskog povezivanja"</string>
+    <string name="upstream_roaming_notification_title" msgid="3015912166812283303">"Uključena je žarišna točka ili modemsko povezivanje"</string>
+    <string name="upstream_roaming_notification_message" msgid="6724434706748439902">"U roamingu su mogući dodatni troškovi"</string>
+</resources>
diff --git a/Tethering/res/values-mcc310-mnc004-hu/strings.xml b/Tethering/res/values-mcc310-mnc004-hu/strings.xml
new file mode 100644
index 0000000..21c689a
--- /dev/null
+++ b/Tethering/res/values-mcc310-mnc004-hu/strings.xml
@@ -0,0 +1,24 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!--  Copyright (C) 2020 The Android Open Source Project
+
+     Licensed under the Apache License, Version 2.0 (the "License");
+     you may not use this file except in compliance with the License.
+     You may obtain a copy of the License at
+
+          http://www.apache.org/licenses/LICENSE-2.0
+
+     Unless required by applicable law or agreed to in writing, software
+     distributed under the License is distributed on an "AS IS" BASIS,
+     WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+     See the License for the specific language governing permissions and
+     limitations under the License.
+ -->
+
+<resources xmlns:android="http://schemas.android.com/apk/res/android"
+    xmlns:xliff="urn:oasis:names:tc:xliff:document:1.2">
+    <string name="no_upstream_notification_title" msgid="5030042590486713460">"Nincs internetkapcsolat az internet megosztásához"</string>
+    <string name="no_upstream_notification_message" msgid="3843613362272973447">"Az eszközök nem tudnak csatlakozni"</string>
+    <string name="no_upstream_notification_disable_button" msgid="6385491461813507624">"Internetmegosztás kikapcsolása"</string>
+    <string name="upstream_roaming_notification_title" msgid="3015912166812283303">"A hotspot vagy az internetmegosztás be van kapcsolva"</string>
+    <string name="upstream_roaming_notification_message" msgid="6724434706748439902">"Roaming során további díjak léphetnek fel"</string>
+</resources>
diff --git a/Tethering/res/values-mcc310-mnc004-hy/strings.xml b/Tethering/res/values-mcc310-mnc004-hy/strings.xml
new file mode 100644
index 0000000..689d928
--- /dev/null
+++ b/Tethering/res/values-mcc310-mnc004-hy/strings.xml
@@ -0,0 +1,24 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!--  Copyright (C) 2020 The Android Open Source Project
+
+     Licensed under the Apache License, Version 2.0 (the "License");
+     you may not use this file except in compliance with the License.
+     You may obtain a copy of the License at
+
+          http://www.apache.org/licenses/LICENSE-2.0
+
+     Unless required by applicable law or agreed to in writing, software
+     distributed under the License is distributed on an "AS IS" BASIS,
+     WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+     See the License for the specific language governing permissions and
+     limitations under the License.
+ -->
+
+<resources xmlns:android="http://schemas.android.com/apk/res/android"
+    xmlns:xliff="urn:oasis:names:tc:xliff:document:1.2">
+    <string name="no_upstream_notification_title" msgid="5030042590486713460">"Մոդեմի ռեժիմի կապը բացակայում է"</string>
+    <string name="no_upstream_notification_message" msgid="3843613362272973447">"Չհաջողվեց միացնել սարքը"</string>
+    <string name="no_upstream_notification_disable_button" msgid="6385491461813507624">"Անջատել մոդեմի ռեժիմը"</string>
+    <string name="upstream_roaming_notification_title" msgid="3015912166812283303">"Թեժ կետը կամ մոդեմի ռեժիմը միացված է"</string>
+    <string name="upstream_roaming_notification_message" msgid="6724434706748439902">"Ռոումինգում կարող են լրացուցիչ վճարներ գանձվել"</string>
+</resources>
diff --git a/Tethering/res/values-mcc310-mnc004-in/strings.xml b/Tethering/res/values-mcc310-mnc004-in/strings.xml
new file mode 100644
index 0000000..a5f4d19
--- /dev/null
+++ b/Tethering/res/values-mcc310-mnc004-in/strings.xml
@@ -0,0 +1,24 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!--  Copyright (C) 2020 The Android Open Source Project
+
+     Licensed under the Apache License, Version 2.0 (the "License");
+     you may not use this file except in compliance with the License.
+     You may obtain a copy of the License at
+
+          http://www.apache.org/licenses/LICENSE-2.0
+
+     Unless required by applicable law or agreed to in writing, software
+     distributed under the License is distributed on an "AS IS" BASIS,
+     WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+     See the License for the specific language governing permissions and
+     limitations under the License.
+ -->
+
+<resources xmlns:android="http://schemas.android.com/apk/res/android"
+    xmlns:xliff="urn:oasis:names:tc:xliff:document:1.2">
+    <string name="no_upstream_notification_title" msgid="5030042590486713460">"Tidak ada koneksi internet di tethering"</string>
+    <string name="no_upstream_notification_message" msgid="3843613362272973447">"Perangkat tidak dapat terhubung"</string>
+    <string name="no_upstream_notification_disable_button" msgid="6385491461813507624">"Nonaktifkan tethering"</string>
+    <string name="upstream_roaming_notification_title" msgid="3015912166812283303">"Hotspot atau tethering aktif"</string>
+    <string name="upstream_roaming_notification_message" msgid="6724434706748439902">"Biaya tambahan mungkin berlaku saat roaming"</string>
+</resources>
diff --git a/Tethering/res/values-mcc310-mnc004-is/strings.xml b/Tethering/res/values-mcc310-mnc004-is/strings.xml
new file mode 100644
index 0000000..fc7e8aa
--- /dev/null
+++ b/Tethering/res/values-mcc310-mnc004-is/strings.xml
@@ -0,0 +1,24 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!--  Copyright (C) 2020 The Android Open Source Project
+
+     Licensed under the Apache License, Version 2.0 (the "License");
+     you may not use this file except in compliance with the License.
+     You may obtain a copy of the License at
+
+          http://www.apache.org/licenses/LICENSE-2.0
+
+     Unless required by applicable law or agreed to in writing, software
+     distributed under the License is distributed on an "AS IS" BASIS,
+     WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+     See the License for the specific language governing permissions and
+     limitations under the License.
+ -->
+
+<resources xmlns:android="http://schemas.android.com/apk/res/android"
+    xmlns:xliff="urn:oasis:names:tc:xliff:document:1.2">
+    <string name="no_upstream_notification_title" msgid="5030042590486713460">"Tjóðrun er ekki með internettengingu"</string>
+    <string name="no_upstream_notification_message" msgid="3843613362272973447">"Tæki geta ekki tengst"</string>
+    <string name="no_upstream_notification_disable_button" msgid="6385491461813507624">"Slökkva á tjóðrun"</string>
+    <string name="upstream_roaming_notification_title" msgid="3015912166812283303">"Kveikt er á heitum reit eða tjóðrun"</string>
+    <string name="upstream_roaming_notification_message" msgid="6724434706748439902">"Viðbótargjöld kunna að eiga við í reiki"</string>
+</resources>
diff --git a/Tethering/res/values-mcc310-mnc004-it/strings.xml b/Tethering/res/values-mcc310-mnc004-it/strings.xml
new file mode 100644
index 0000000..6456dd1
--- /dev/null
+++ b/Tethering/res/values-mcc310-mnc004-it/strings.xml
@@ -0,0 +1,24 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!--  Copyright (C) 2020 The Android Open Source Project
+
+     Licensed under the Apache License, Version 2.0 (the "License");
+     you may not use this file except in compliance with the License.
+     You may obtain a copy of the License at
+
+          http://www.apache.org/licenses/LICENSE-2.0
+
+     Unless required by applicable law or agreed to in writing, software
+     distributed under the License is distributed on an "AS IS" BASIS,
+     WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+     See the License for the specific language governing permissions and
+     limitations under the License.
+ -->
+
+<resources xmlns:android="http://schemas.android.com/apk/res/android"
+    xmlns:xliff="urn:oasis:names:tc:xliff:document:1.2">
+    <string name="no_upstream_notification_title" msgid="5030042590486713460">"Nessuna connessione a Internet per il tethering"</string>
+    <string name="no_upstream_notification_message" msgid="3843613362272973447">"Impossibile connettere i dispositivi"</string>
+    <string name="no_upstream_notification_disable_button" msgid="6385491461813507624">"Disattiva il tethering"</string>
+    <string name="upstream_roaming_notification_title" msgid="3015912166812283303">"Hotspot o tethering attivi"</string>
+    <string name="upstream_roaming_notification_message" msgid="6724434706748439902">"Potrebbero essere applicati costi aggiuntivi durante il roaming"</string>
+</resources>
diff --git a/Tethering/res/values-mcc310-mnc004-iw/strings.xml b/Tethering/res/values-mcc310-mnc004-iw/strings.xml
new file mode 100644
index 0000000..46b24bd
--- /dev/null
+++ b/Tethering/res/values-mcc310-mnc004-iw/strings.xml
@@ -0,0 +1,24 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!--  Copyright (C) 2020 The Android Open Source Project
+
+     Licensed under the Apache License, Version 2.0 (the "License");
+     you may not use this file except in compliance with the License.
+     You may obtain a copy of the License at
+
+          http://www.apache.org/licenses/LICENSE-2.0
+
+     Unless required by applicable law or agreed to in writing, software
+     distributed under the License is distributed on an "AS IS" BASIS,
+     WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+     See the License for the specific language governing permissions and
+     limitations under the License.
+ -->
+
+<resources xmlns:android="http://schemas.android.com/apk/res/android"
+    xmlns:xliff="urn:oasis:names:tc:xliff:document:1.2">
+    <string name="no_upstream_notification_title" msgid="5030042590486713460">"אי אפשר להפעיל את תכונת שיתוף האינטרנט בין מכשירים כי אין חיבור לאינטרנט"</string>
+    <string name="no_upstream_notification_message" msgid="3843613362272973447">"למכשירים אין אפשרות להתחבר"</string>
+    <string name="no_upstream_notification_disable_button" msgid="6385491461813507624">"השבתה של שיתוף האינטרנט בין מכשירים"</string>
+    <string name="upstream_roaming_notification_title" msgid="3015912166812283303">"תכונת הנקודה לשיתוף אינטרנט או תכונת שיתוף האינטרנט בין מכשירים פועלת"</string>
+    <string name="upstream_roaming_notification_message" msgid="6724434706748439902">"ייתכנו חיובים נוספים בעת נדידה"</string>
+</resources>
diff --git a/Tethering/res/values-mcc310-mnc004-ja/strings.xml b/Tethering/res/values-mcc310-mnc004-ja/strings.xml
new file mode 100644
index 0000000..e6eb277
--- /dev/null
+++ b/Tethering/res/values-mcc310-mnc004-ja/strings.xml
@@ -0,0 +1,24 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!--  Copyright (C) 2020 The Android Open Source Project
+
+     Licensed under the Apache License, Version 2.0 (the "License");
+     you may not use this file except in compliance with the License.
+     You may obtain a copy of the License at
+
+          http://www.apache.org/licenses/LICENSE-2.0
+
+     Unless required by applicable law or agreed to in writing, software
+     distributed under the License is distributed on an "AS IS" BASIS,
+     WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+     See the License for the specific language governing permissions and
+     limitations under the License.
+ -->
+
+<resources xmlns:android="http://schemas.android.com/apk/res/android"
+    xmlns:xliff="urn:oasis:names:tc:xliff:document:1.2">
+    <string name="no_upstream_notification_title" msgid="5030042590486713460">"テザリングがインターネットに接続されていません"</string>
+    <string name="no_upstream_notification_message" msgid="3843613362272973447">"デバイスを接続できません"</string>
+    <string name="no_upstream_notification_disable_button" msgid="6385491461813507624">"テザリングを OFF にする"</string>
+    <string name="upstream_roaming_notification_title" msgid="3015912166812283303">"アクセス ポイントまたはテザリングが ON です"</string>
+    <string name="upstream_roaming_notification_message" msgid="6724434706748439902">"ローミング時に追加料金が発生することがあります"</string>
+</resources>
diff --git a/Tethering/res/values-mcc310-mnc004-ka/strings.xml b/Tethering/res/values-mcc310-mnc004-ka/strings.xml
new file mode 100644
index 0000000..aeddd71
--- /dev/null
+++ b/Tethering/res/values-mcc310-mnc004-ka/strings.xml
@@ -0,0 +1,24 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!--  Copyright (C) 2020 The Android Open Source Project
+
+     Licensed under the Apache License, Version 2.0 (the "License");
+     you may not use this file except in compliance with the License.
+     You may obtain a copy of the License at
+
+          http://www.apache.org/licenses/LICENSE-2.0
+
+     Unless required by applicable law or agreed to in writing, software
+     distributed under the License is distributed on an "AS IS" BASIS,
+     WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+     See the License for the specific language governing permissions and
+     limitations under the License.
+ -->
+
+<resources xmlns:android="http://schemas.android.com/apk/res/android"
+    xmlns:xliff="urn:oasis:names:tc:xliff:document:1.2">
+    <string name="no_upstream_notification_title" msgid="5030042590486713460">"ტეტერინგს არ აქვს ინტერნეტზე წვდომა"</string>
+    <string name="no_upstream_notification_message" msgid="3843613362272973447">"მოწყობილობები ვერ ახერხებენ დაკავშირებას"</string>
+    <string name="no_upstream_notification_disable_button" msgid="6385491461813507624">"ტეტერინგის გამორთვა"</string>
+    <string name="upstream_roaming_notification_title" msgid="3015912166812283303">"ჩართულია უსადენო ქსელი ან ტეტერინგი"</string>
+    <string name="upstream_roaming_notification_message" msgid="6724434706748439902">"როუმინგის გამოყენებისას შეიძლება ჩამოგეჭრათ დამატებითი საფასური"</string>
+</resources>
diff --git a/Tethering/res/values-mcc310-mnc004-kk/strings.xml b/Tethering/res/values-mcc310-mnc004-kk/strings.xml
new file mode 100644
index 0000000..255f0a2
--- /dev/null
+++ b/Tethering/res/values-mcc310-mnc004-kk/strings.xml
@@ -0,0 +1,24 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!--  Copyright (C) 2020 The Android Open Source Project
+
+     Licensed under the Apache License, Version 2.0 (the "License");
+     you may not use this file except in compliance with the License.
+     You may obtain a copy of the License at
+
+          http://www.apache.org/licenses/LICENSE-2.0
+
+     Unless required by applicable law or agreed to in writing, software
+     distributed under the License is distributed on an "AS IS" BASIS,
+     WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+     See the License for the specific language governing permissions and
+     limitations under the License.
+ -->
+
+<resources xmlns:android="http://schemas.android.com/apk/res/android"
+    xmlns:xliff="urn:oasis:names:tc:xliff:document:1.2">
+    <string name="no_upstream_notification_title" msgid="5030042590486713460">"Тетеринг режимі интернет байланысынсыз пайдаланылуда"</string>
+    <string name="no_upstream_notification_message" msgid="3843613362272973447">"Құрылғыларды байланыстыру мүмкін емес"</string>
+    <string name="no_upstream_notification_disable_button" msgid="6385491461813507624">"Тетерингіні өшіру"</string>
+    <string name="upstream_roaming_notification_title" msgid="3015912166812283303">"Хотспот немесе тетеринг қосулы"</string>
+    <string name="upstream_roaming_notification_message" msgid="6724434706748439902">"Роуминг кезінде қосымша ақы алынуы мүмкін."</string>
+</resources>
diff --git a/Tethering/res/values-mcc310-mnc004-km/strings.xml b/Tethering/res/values-mcc310-mnc004-km/strings.xml
new file mode 100644
index 0000000..2bceb1c
--- /dev/null
+++ b/Tethering/res/values-mcc310-mnc004-km/strings.xml
@@ -0,0 +1,24 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!--  Copyright (C) 2020 The Android Open Source Project
+
+     Licensed under the Apache License, Version 2.0 (the "License");
+     you may not use this file except in compliance with the License.
+     You may obtain a copy of the License at
+
+          http://www.apache.org/licenses/LICENSE-2.0
+
+     Unless required by applicable law or agreed to in writing, software
+     distributed under the License is distributed on an "AS IS" BASIS,
+     WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+     See the License for the specific language governing permissions and
+     limitations under the License.
+ -->
+
+<resources xmlns:android="http://schemas.android.com/apk/res/android"
+    xmlns:xliff="urn:oasis:names:tc:xliff:document:1.2">
+    <string name="no_upstream_notification_title" msgid="5030042590486713460">"ការភ្ជាប់​មិនមានអ៊ីនធឺណិត​ទេ"</string>
+    <string name="no_upstream_notification_message" msgid="3843613362272973447">"មិនអាច​ភ្ជាប់ឧបករណ៍​បានទេ"</string>
+    <string name="no_upstream_notification_disable_button" msgid="6385491461813507624">"បិទការភ្ជាប់"</string>
+    <string name="upstream_roaming_notification_title" msgid="3015912166812283303">"ហតស្ប៉ត ឬការភ្ជាប់​ត្រូវបានបើក"</string>
+    <string name="upstream_roaming_notification_message" msgid="6724434706748439902">"អាចមាន​ការគិតថ្លៃ​បន្ថែម នៅពេល​រ៉ូមីង"</string>
+</resources>
diff --git a/Tethering/res/values-mcc310-mnc004-kn/strings.xml b/Tethering/res/values-mcc310-mnc004-kn/strings.xml
new file mode 100644
index 0000000..ed76930
--- /dev/null
+++ b/Tethering/res/values-mcc310-mnc004-kn/strings.xml
@@ -0,0 +1,24 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!--  Copyright (C) 2020 The Android Open Source Project
+
+     Licensed under the Apache License, Version 2.0 (the "License");
+     you may not use this file except in compliance with the License.
+     You may obtain a copy of the License at
+
+          http://www.apache.org/licenses/LICENSE-2.0
+
+     Unless required by applicable law or agreed to in writing, software
+     distributed under the License is distributed on an "AS IS" BASIS,
+     WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+     See the License for the specific language governing permissions and
+     limitations under the License.
+ -->
+
+<resources xmlns:android="http://schemas.android.com/apk/res/android"
+    xmlns:xliff="urn:oasis:names:tc:xliff:document:1.2">
+    <string name="no_upstream_notification_title" msgid="5030042590486713460">"ಟೆಥರಿಂಗ್‌ ಯಾವುದೇ ಇಂಟರ್ನೆಟ್ ಕನೆಕ್ಷನ್ ಹೊಂದಿಲ್ಲ"</string>
+    <string name="no_upstream_notification_message" msgid="3843613362272973447">"ಸಾಧನಗಳನ್ನು ಕನೆಕ್ಟ್ ಮಾಡಲು ಸಾಧ್ಯವಿಲ್ಲ"</string>
+    <string name="no_upstream_notification_disable_button" msgid="6385491461813507624">"ಟೆಥರಿಂಗ್‌ ಆಫ್ ಮಾಡಿ"</string>
+    <string name="upstream_roaming_notification_title" msgid="3015912166812283303">"ಹಾಟ್‌ಸ್ಪಾಟ್ ಅಥವಾ ಟೆಥರಿಂಗ್‌ ಆನ್ ಆಗಿದೆ"</string>
+    <string name="upstream_roaming_notification_message" msgid="6724434706748439902">"ರೋಮಿಂಗ್‌ನಲ್ಲಿರುವಾಗ ಹೆಚ್ಚುವರಿ ಶುಲ್ಕಗಳು ಅನ್ವಯವಾಗಬಹುದು"</string>
+</resources>
diff --git a/Tethering/res/values-mcc310-mnc004-ko/strings.xml b/Tethering/res/values-mcc310-mnc004-ko/strings.xml
new file mode 100644
index 0000000..6e50494
--- /dev/null
+++ b/Tethering/res/values-mcc310-mnc004-ko/strings.xml
@@ -0,0 +1,24 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!--  Copyright (C) 2020 The Android Open Source Project
+
+     Licensed under the Apache License, Version 2.0 (the "License");
+     you may not use this file except in compliance with the License.
+     You may obtain a copy of the License at
+
+          http://www.apache.org/licenses/LICENSE-2.0
+
+     Unless required by applicable law or agreed to in writing, software
+     distributed under the License is distributed on an "AS IS" BASIS,
+     WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+     See the License for the specific language governing permissions and
+     limitations under the License.
+ -->
+
+<resources xmlns:android="http://schemas.android.com/apk/res/android"
+    xmlns:xliff="urn:oasis:names:tc:xliff:document:1.2">
+    <string name="no_upstream_notification_title" msgid="5030042590486713460">"테더링으로 인터넷을 사용할 수 없음"</string>
+    <string name="no_upstream_notification_message" msgid="3843613362272973447">"기기에서 연결할 수 없음"</string>
+    <string name="no_upstream_notification_disable_button" msgid="6385491461813507624">"테더링 사용 중지"</string>
+    <string name="upstream_roaming_notification_title" msgid="3015912166812283303">"핫스팟 또는 테더링 켜짐"</string>
+    <string name="upstream_roaming_notification_message" msgid="6724434706748439902">"로밍 중에는 추가 요금이 발생할 수 있습니다."</string>
+</resources>
diff --git a/Tethering/res/values-mcc310-mnc004-ky/strings.xml b/Tethering/res/values-mcc310-mnc004-ky/strings.xml
new file mode 100644
index 0000000..d68128b
--- /dev/null
+++ b/Tethering/res/values-mcc310-mnc004-ky/strings.xml
@@ -0,0 +1,24 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!--  Copyright (C) 2020 The Android Open Source Project
+
+     Licensed under the Apache License, Version 2.0 (the "License");
+     you may not use this file except in compliance with the License.
+     You may obtain a copy of the License at
+
+          http://www.apache.org/licenses/LICENSE-2.0
+
+     Unless required by applicable law or agreed to in writing, software
+     distributed under the License is distributed on an "AS IS" BASIS,
+     WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+     See the License for the specific language governing permissions and
+     limitations under the License.
+ -->
+
+<resources xmlns:android="http://schemas.android.com/apk/res/android"
+    xmlns:xliff="urn:oasis:names:tc:xliff:document:1.2">
+    <string name="no_upstream_notification_title" msgid="5030042590486713460">"Модем режими Интернети жок колдонулууда"</string>
+    <string name="no_upstream_notification_message" msgid="3843613362272973447">"Түзмөктөр туташпай жатат"</string>
+    <string name="no_upstream_notification_disable_button" msgid="6385491461813507624">"Модем режимин өчүрүү"</string>
+    <string name="upstream_roaming_notification_title" msgid="3015912166812283303">"Байланыш түйүнү же модем режими күйүк"</string>
+    <string name="upstream_roaming_notification_message" msgid="6724434706748439902">"Роумингде кошумча акы алынышы мүмкүн"</string>
+</resources>
diff --git a/Tethering/res/values-mcc310-mnc004-lo/strings.xml b/Tethering/res/values-mcc310-mnc004-lo/strings.xml
new file mode 100644
index 0000000..03e134a
--- /dev/null
+++ b/Tethering/res/values-mcc310-mnc004-lo/strings.xml
@@ -0,0 +1,24 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!--  Copyright (C) 2020 The Android Open Source Project
+
+     Licensed under the Apache License, Version 2.0 (the "License");
+     you may not use this file except in compliance with the License.
+     You may obtain a copy of the License at
+
+          http://www.apache.org/licenses/LICENSE-2.0
+
+     Unless required by applicable law or agreed to in writing, software
+     distributed under the License is distributed on an "AS IS" BASIS,
+     WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+     See the License for the specific language governing permissions and
+     limitations under the License.
+ -->
+
+<resources xmlns:android="http://schemas.android.com/apk/res/android"
+    xmlns:xliff="urn:oasis:names:tc:xliff:document:1.2">
+    <string name="no_upstream_notification_title" msgid="5030042590486713460">"ການປ່ອຍສັນຍານບໍ່ມີອິນເຕີເນັດ"</string>
+    <string name="no_upstream_notification_message" msgid="3843613362272973447">"ອຸປະກອນບໍ່ສາມາດເຊື່ອມຕໍ່ໄດ້"</string>
+    <string name="no_upstream_notification_disable_button" msgid="6385491461813507624">"ປິດການປ່ອຍສັນຍານ"</string>
+    <string name="upstream_roaming_notification_title" msgid="3015912166812283303">"ເປີດໃຊ້ຮັອດສະປອດ ຫຼື ການປ່ອຍສັນຍານຢູ່"</string>
+    <string name="upstream_roaming_notification_message" msgid="6724434706748439902">"ອາດມີຄ່າໃຊ້ຈ່າຍເພີ່ມເຕີມໃນລະຫວ່າງການໂຣມມິງ"</string>
+</resources>
diff --git a/Tethering/res/values-mcc310-mnc004-lt/strings.xml b/Tethering/res/values-mcc310-mnc004-lt/strings.xml
new file mode 100644
index 0000000..652cedc
--- /dev/null
+++ b/Tethering/res/values-mcc310-mnc004-lt/strings.xml
@@ -0,0 +1,24 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!--  Copyright (C) 2020 The Android Open Source Project
+
+     Licensed under the Apache License, Version 2.0 (the "License");
+     you may not use this file except in compliance with the License.
+     You may obtain a copy of the License at
+
+          http://www.apache.org/licenses/LICENSE-2.0
+
+     Unless required by applicable law or agreed to in writing, software
+     distributed under the License is distributed on an "AS IS" BASIS,
+     WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+     See the License for the specific language governing permissions and
+     limitations under the License.
+ -->
+
+<resources xmlns:android="http://schemas.android.com/apk/res/android"
+    xmlns:xliff="urn:oasis:names:tc:xliff:document:1.2">
+    <string name="no_upstream_notification_title" msgid="5030042590486713460">"Nėra įrenginio kaip modemo naudojimo interneto ryšio"</string>
+    <string name="no_upstream_notification_message" msgid="3843613362272973447">"Nepavyko susieti įrenginių"</string>
+    <string name="no_upstream_notification_disable_button" msgid="6385491461813507624">"Išjungti įrenginio kaip modemo naudojimą"</string>
+    <string name="upstream_roaming_notification_title" msgid="3015912166812283303">"Įjungtas viešosios interneto prieigos taškas arba įrenginio kaip modemo naudojimas"</string>
+    <string name="upstream_roaming_notification_message" msgid="6724434706748439902">"Veikiant tarptinkliniam ryšiui gali būti taikomi papildomi mokesčiai"</string>
+</resources>
diff --git a/Tethering/res/values-mcc310-mnc004-lv/strings.xml b/Tethering/res/values-mcc310-mnc004-lv/strings.xml
new file mode 100644
index 0000000..2219722
--- /dev/null
+++ b/Tethering/res/values-mcc310-mnc004-lv/strings.xml
@@ -0,0 +1,24 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!--  Copyright (C) 2020 The Android Open Source Project
+
+     Licensed under the Apache License, Version 2.0 (the "License");
+     you may not use this file except in compliance with the License.
+     You may obtain a copy of the License at
+
+          http://www.apache.org/licenses/LICENSE-2.0
+
+     Unless required by applicable law or agreed to in writing, software
+     distributed under the License is distributed on an "AS IS" BASIS,
+     WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+     See the License for the specific language governing permissions and
+     limitations under the License.
+ -->
+
+<resources xmlns:android="http://schemas.android.com/apk/res/android"
+    xmlns:xliff="urn:oasis:names:tc:xliff:document:1.2">
+    <string name="no_upstream_notification_title" msgid="5030042590486713460">"Piesaistei nav interneta savienojuma"</string>
+    <string name="no_upstream_notification_message" msgid="3843613362272973447">"Nevar savienot ierīces"</string>
+    <string name="no_upstream_notification_disable_button" msgid="6385491461813507624">"Izslēgt piesaisti"</string>
+    <string name="upstream_roaming_notification_title" msgid="3015912166812283303">"Ir ieslēgts tīklājs vai piesaiste"</string>
+    <string name="upstream_roaming_notification_message" msgid="6724434706748439902">"Viesabonēšanas laikā var tikt piemērota papildu samaksa"</string>
+</resources>
diff --git a/Tethering/res/values-mcc310-mnc004-mk/strings.xml b/Tethering/res/values-mcc310-mnc004-mk/strings.xml
new file mode 100644
index 0000000..227f9e3
--- /dev/null
+++ b/Tethering/res/values-mcc310-mnc004-mk/strings.xml
@@ -0,0 +1,24 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!--  Copyright (C) 2020 The Android Open Source Project
+
+     Licensed under the Apache License, Version 2.0 (the "License");
+     you may not use this file except in compliance with the License.
+     You may obtain a copy of the License at
+
+          http://www.apache.org/licenses/LICENSE-2.0
+
+     Unless required by applicable law or agreed to in writing, software
+     distributed under the License is distributed on an "AS IS" BASIS,
+     WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+     See the License for the specific language governing permissions and
+     limitations under the License.
+ -->
+
+<resources xmlns:android="http://schemas.android.com/apk/res/android"
+    xmlns:xliff="urn:oasis:names:tc:xliff:document:1.2">
+    <string name="no_upstream_notification_title" msgid="5030042590486713460">"Нема интернет преку мобилен"</string>
+    <string name="no_upstream_notification_message" msgid="3843613362272973447">"Уредите не може да се поврзат"</string>
+    <string name="no_upstream_notification_disable_button" msgid="6385491461813507624">"Исклучи интернет преку мобилен"</string>
+    <string name="upstream_roaming_notification_title" msgid="3015912166812283303">"Точката на пристап или интернетот преку мобилен е вклучен"</string>
+    <string name="upstream_roaming_notification_message" msgid="6724434706748439902">"При роаминг може да се наплатат дополнителни трошоци"</string>
+</resources>
diff --git a/Tethering/res/values-mcc310-mnc004-ml/strings.xml b/Tethering/res/values-mcc310-mnc004-ml/strings.xml
new file mode 100644
index 0000000..ec43885
--- /dev/null
+++ b/Tethering/res/values-mcc310-mnc004-ml/strings.xml
@@ -0,0 +1,24 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!--  Copyright (C) 2020 The Android Open Source Project
+
+     Licensed under the Apache License, Version 2.0 (the "License");
+     you may not use this file except in compliance with the License.
+     You may obtain a copy of the License at
+
+          http://www.apache.org/licenses/LICENSE-2.0
+
+     Unless required by applicable law or agreed to in writing, software
+     distributed under the License is distributed on an "AS IS" BASIS,
+     WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+     See the License for the specific language governing permissions and
+     limitations under the License.
+ -->
+
+<resources xmlns:android="http://schemas.android.com/apk/res/android"
+    xmlns:xliff="urn:oasis:names:tc:xliff:document:1.2">
+    <string name="no_upstream_notification_title" msgid="5030042590486713460">"ടെതറിംഗിന് ഇന്റർനെറ്റ് ഇല്ല"</string>
+    <string name="no_upstream_notification_message" msgid="3843613362272973447">"ഉപകരണങ്ങൾ കണക്റ്റ് ചെയ്യാനാവില്ല"</string>
+    <string name="no_upstream_notification_disable_button" msgid="6385491461813507624">"ടെതറിംഗ് ഓഫാക്കുക"</string>
+    <string name="upstream_roaming_notification_title" msgid="3015912166812283303">"ഹോട്ട്‌സ്‌പോട്ട് അല്ലെങ്കിൽ ടെതറിംഗ് ഓണാണ്"</string>
+    <string name="upstream_roaming_notification_message" msgid="6724434706748439902">"റോമിംഗ് ചെയ്യുമ്പോൾ അധിക നിരക്കുകൾ ബാധകമായേക്കാം"</string>
+</resources>
diff --git a/Tethering/res/values-mcc310-mnc004-mn/strings.xml b/Tethering/res/values-mcc310-mnc004-mn/strings.xml
new file mode 100644
index 0000000..e263573
--- /dev/null
+++ b/Tethering/res/values-mcc310-mnc004-mn/strings.xml
@@ -0,0 +1,24 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!--  Copyright (C) 2020 The Android Open Source Project
+
+     Licensed under the Apache License, Version 2.0 (the "License");
+     you may not use this file except in compliance with the License.
+     You may obtain a copy of the License at
+
+          http://www.apache.org/licenses/LICENSE-2.0
+
+     Unless required by applicable law or agreed to in writing, software
+     distributed under the License is distributed on an "AS IS" BASIS,
+     WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+     See the License for the specific language governing permissions and
+     limitations under the License.
+ -->
+
+<resources xmlns:android="http://schemas.android.com/apk/res/android"
+    xmlns:xliff="urn:oasis:names:tc:xliff:document:1.2">
+    <string name="no_upstream_notification_title" msgid="5030042590486713460">"Модемд интернэт алга байна"</string>
+    <string name="no_upstream_notification_message" msgid="3843613362272973447">"Төхөөрөмжүүд холбогдох боломжгүй байна"</string>
+    <string name="no_upstream_notification_disable_button" msgid="6385491461813507624">"Модем болгохыг унтраах"</string>
+    <string name="upstream_roaming_notification_title" msgid="3015912166812283303">"Сүлжээний цэг эсвэл модем болгох асаалттай байна"</string>
+    <string name="upstream_roaming_notification_message" msgid="6724434706748439902">"Роумингийн үеэр нэмэлт төлбөр нэхэмжилж болзошгүй"</string>
+</resources>
diff --git a/Tethering/res/values-mcc310-mnc004-mr/strings.xml b/Tethering/res/values-mcc310-mnc004-mr/strings.xml
new file mode 100644
index 0000000..adf845d
--- /dev/null
+++ b/Tethering/res/values-mcc310-mnc004-mr/strings.xml
@@ -0,0 +1,24 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!--  Copyright (C) 2020 The Android Open Source Project
+
+     Licensed under the Apache License, Version 2.0 (the "License");
+     you may not use this file except in compliance with the License.
+     You may obtain a copy of the License at
+
+          http://www.apache.org/licenses/LICENSE-2.0
+
+     Unless required by applicable law or agreed to in writing, software
+     distributed under the License is distributed on an "AS IS" BASIS,
+     WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+     See the License for the specific language governing permissions and
+     limitations under the License.
+ -->
+
+<resources xmlns:android="http://schemas.android.com/apk/res/android"
+    xmlns:xliff="urn:oasis:names:tc:xliff:document:1.2">
+    <string name="no_upstream_notification_title" msgid="5030042590486713460">"टेदरिंगला इंटरनेट नाही"</string>
+    <string name="no_upstream_notification_message" msgid="3843613362272973447">"डिव्हाइस कनेक्ट होऊ शकत नाहीत"</string>
+    <string name="no_upstream_notification_disable_button" msgid="6385491461813507624">"टेदरिंग बंद करा"</string>
+    <string name="upstream_roaming_notification_title" msgid="3015912166812283303">"हॉटस्पॉट किंवा टेदरिंग सुरू आहे"</string>
+    <string name="upstream_roaming_notification_message" msgid="6724434706748439902">"रोमिंगदरम्यान अतिरिक्त शुल्क लागू होऊ शकतात"</string>
+</resources>
diff --git a/Tethering/res/values-mcc310-mnc004-ms/strings.xml b/Tethering/res/values-mcc310-mnc004-ms/strings.xml
new file mode 100644
index 0000000..f65c451
--- /dev/null
+++ b/Tethering/res/values-mcc310-mnc004-ms/strings.xml
@@ -0,0 +1,24 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!--  Copyright (C) 2020 The Android Open Source Project
+
+     Licensed under the Apache License, Version 2.0 (the "License");
+     you may not use this file except in compliance with the License.
+     You may obtain a copy of the License at
+
+          http://www.apache.org/licenses/LICENSE-2.0
+
+     Unless required by applicable law or agreed to in writing, software
+     distributed under the License is distributed on an "AS IS" BASIS,
+     WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+     See the License for the specific language governing permissions and
+     limitations under the License.
+ -->
+
+<resources xmlns:android="http://schemas.android.com/apk/res/android"
+    xmlns:xliff="urn:oasis:names:tc:xliff:document:1.2">
+    <string name="no_upstream_notification_title" msgid="5030042590486713460">"Penambatan tiada Internet"</string>
+    <string name="no_upstream_notification_message" msgid="3843613362272973447">"Peranti tidak dapat disambungkan"</string>
+    <string name="no_upstream_notification_disable_button" msgid="6385491461813507624">"Matikan penambatan"</string>
+    <string name="upstream_roaming_notification_title" msgid="3015912166812283303">"Tempat liputan atau penambatan dihidupkan"</string>
+    <string name="upstream_roaming_notification_message" msgid="6724434706748439902">"Caj tambahan mungkin digunakan semasa perayauan"</string>
+</resources>
diff --git a/Tethering/res/values-mcc310-mnc004-my/strings.xml b/Tethering/res/values-mcc310-mnc004-my/strings.xml
new file mode 100644
index 0000000..4118e77
--- /dev/null
+++ b/Tethering/res/values-mcc310-mnc004-my/strings.xml
@@ -0,0 +1,24 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!--  Copyright (C) 2020 The Android Open Source Project
+
+     Licensed under the Apache License, Version 2.0 (the "License");
+     you may not use this file except in compliance with the License.
+     You may obtain a copy of the License at
+
+          http://www.apache.org/licenses/LICENSE-2.0
+
+     Unless required by applicable law or agreed to in writing, software
+     distributed under the License is distributed on an "AS IS" BASIS,
+     WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+     See the License for the specific language governing permissions and
+     limitations under the License.
+ -->
+
+<resources xmlns:android="http://schemas.android.com/apk/res/android"
+    xmlns:xliff="urn:oasis:names:tc:xliff:document:1.2">
+    <string name="no_upstream_notification_title" msgid="5030042590486713460">"မိုဘိုင်းဖုန်းသုံး ချိတ်ဆက်မျှဝေခြင်းတွင် အင်တာနက် မရှိပါ"</string>
+    <string name="no_upstream_notification_message" msgid="3843613362272973447">"စက်များ ချိတ်ဆက်၍ မရပါ"</string>
+    <string name="no_upstream_notification_disable_button" msgid="6385491461813507624">"မိုဘိုင်းဖုန်းသုံး ချိတ်ဆက်မျှဝေခြင်း ပိတ်ရန်"</string>
+    <string name="upstream_roaming_notification_title" msgid="3015912166812283303">"ဟော့စပေါ့ (သို့) မိုဘိုင်းဖုန်းသုံး ချိတ်ဆက်မျှဝေခြင်း ဖွင့်ထားသည်"</string>
+    <string name="upstream_roaming_notification_message" msgid="6724434706748439902">"ပြင်ပကွန်ရက်နှင့် ချိတ်ဆက်သည့်အခါ နောက်ထပ်ကျသင့်မှုများ ရှိနိုင်သည်"</string>
+</resources>
diff --git a/Tethering/res/values-mcc310-mnc004-nb/strings.xml b/Tethering/res/values-mcc310-mnc004-nb/strings.xml
new file mode 100644
index 0000000..3685358
--- /dev/null
+++ b/Tethering/res/values-mcc310-mnc004-nb/strings.xml
@@ -0,0 +1,24 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!--  Copyright (C) 2020 The Android Open Source Project
+
+     Licensed under the Apache License, Version 2.0 (the "License");
+     you may not use this file except in compliance with the License.
+     You may obtain a copy of the License at
+
+          http://www.apache.org/licenses/LICENSE-2.0
+
+     Unless required by applicable law or agreed to in writing, software
+     distributed under the License is distributed on an "AS IS" BASIS,
+     WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+     See the License for the specific language governing permissions and
+     limitations under the License.
+ -->
+
+<resources xmlns:android="http://schemas.android.com/apk/res/android"
+    xmlns:xliff="urn:oasis:names:tc:xliff:document:1.2">
+    <string name="no_upstream_notification_title" msgid="5030042590486713460">"Internettdeling har ikke internettilgang"</string>
+    <string name="no_upstream_notification_message" msgid="3843613362272973447">"Enhetene kan ikke koble til"</string>
+    <string name="no_upstream_notification_disable_button" msgid="6385491461813507624">"Slå av internettdeling"</string>
+    <string name="upstream_roaming_notification_title" msgid="3015912166812283303">"Wi-Fi-sone eller internettdeling er på"</string>
+    <string name="upstream_roaming_notification_message" msgid="6724434706748439902">"Ytterligere kostnader kan påløpe under roaming"</string>
+</resources>
diff --git a/Tethering/res/values-mcc310-mnc004-ne/strings.xml b/Tethering/res/values-mcc310-mnc004-ne/strings.xml
new file mode 100644
index 0000000..d074f15
--- /dev/null
+++ b/Tethering/res/values-mcc310-mnc004-ne/strings.xml
@@ -0,0 +1,24 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!--  Copyright (C) 2020 The Android Open Source Project
+
+     Licensed under the Apache License, Version 2.0 (the "License");
+     you may not use this file except in compliance with the License.
+     You may obtain a copy of the License at
+
+          http://www.apache.org/licenses/LICENSE-2.0
+
+     Unless required by applicable law or agreed to in writing, software
+     distributed under the License is distributed on an "AS IS" BASIS,
+     WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+     See the License for the specific language governing permissions and
+     limitations under the License.
+ -->
+
+<resources xmlns:android="http://schemas.android.com/apk/res/android"
+    xmlns:xliff="urn:oasis:names:tc:xliff:document:1.2">
+    <string name="no_upstream_notification_title" msgid="5030042590486713460">"टेदरिङमार्फत इन्टरनेट कनेक्सन प्राप्त हुन सकेन"</string>
+    <string name="no_upstream_notification_message" msgid="3843613362272973447">"यन्त्रहरू कनेक्ट गर्न सकिएन"</string>
+    <string name="no_upstream_notification_disable_button" msgid="6385491461813507624">"टेदरिङ निष्क्रिय पार्नुहोस्"</string>
+    <string name="upstream_roaming_notification_title" msgid="3015912166812283303">"हटस्पट वा टेदरिङ सक्रिय छ"</string>
+    <string name="upstream_roaming_notification_message" msgid="6724434706748439902">"रोमिङ सेवा प्रयोग गर्दा अतिरिक्त शुल्क लाग्न सक्छ"</string>
+</resources>
diff --git a/Tethering/res/values-mcc310-mnc004-nl/strings.xml b/Tethering/res/values-mcc310-mnc004-nl/strings.xml
new file mode 100644
index 0000000..1d88894
--- /dev/null
+++ b/Tethering/res/values-mcc310-mnc004-nl/strings.xml
@@ -0,0 +1,24 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!--  Copyright (C) 2020 The Android Open Source Project
+
+     Licensed under the Apache License, Version 2.0 (the "License");
+     you may not use this file except in compliance with the License.
+     You may obtain a copy of the License at
+
+          http://www.apache.org/licenses/LICENSE-2.0
+
+     Unless required by applicable law or agreed to in writing, software
+     distributed under the License is distributed on an "AS IS" BASIS,
+     WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+     See the License for the specific language governing permissions and
+     limitations under the License.
+ -->
+
+<resources xmlns:android="http://schemas.android.com/apk/res/android"
+    xmlns:xliff="urn:oasis:names:tc:xliff:document:1.2">
+    <string name="no_upstream_notification_title" msgid="5030042590486713460">"Tethering heeft geen internet"</string>
+    <string name="no_upstream_notification_message" msgid="3843613362272973447">"Apparaten kunnen niet worden verbonden"</string>
+    <string name="no_upstream_notification_disable_button" msgid="6385491461813507624">"Tethering uitschakelen"</string>
+    <string name="upstream_roaming_notification_title" msgid="3015912166812283303">"Hotspot of tethering is ingeschakeld"</string>
+    <string name="upstream_roaming_notification_message" msgid="6724434706748439902">"Er kunnen extra kosten voor roaming in rekening worden gebracht."</string>
+</resources>
diff --git a/Tethering/res/values-mcc310-mnc004-or/strings.xml b/Tethering/res/values-mcc310-mnc004-or/strings.xml
new file mode 100644
index 0000000..8038815
--- /dev/null
+++ b/Tethering/res/values-mcc310-mnc004-or/strings.xml
@@ -0,0 +1,24 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!--  Copyright (C) 2020 The Android Open Source Project
+
+     Licensed under the Apache License, Version 2.0 (the "License");
+     you may not use this file except in compliance with the License.
+     You may obtain a copy of the License at
+
+          http://www.apache.org/licenses/LICENSE-2.0
+
+     Unless required by applicable law or agreed to in writing, software
+     distributed under the License is distributed on an "AS IS" BASIS,
+     WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+     See the License for the specific language governing permissions and
+     limitations under the License.
+ -->
+
+<resources xmlns:android="http://schemas.android.com/apk/res/android"
+    xmlns:xliff="urn:oasis:names:tc:xliff:document:1.2">
+    <string name="no_upstream_notification_title" msgid="5030042590486713460">"ଟିଥରିଂ ପାଇଁ କୌଣସି ଇଣ୍ଟର୍ନେଟ୍ ସଂଯୋଗ ନାହିଁ"</string>
+    <string name="no_upstream_notification_message" msgid="3843613362272973447">"ଡିଭାଇସଗୁଡ଼ିକ ସଂଯୋଗ କରାଯାଇପାରିବ ନାହିଁ"</string>
+    <string name="no_upstream_notification_disable_button" msgid="6385491461813507624">"ଟିଥରିଂ ବନ୍ଦ କରନ୍ତୁ"</string>
+    <string name="upstream_roaming_notification_title" msgid="3015912166812283303">"ହଟସ୍ପଟ୍ କିମ୍ବା ଟିଥରିଂ ଚାଲୁ ଅଛି"</string>
+    <string name="upstream_roaming_notification_message" msgid="6724434706748439902">"ରୋମିଂରେ ଥିବା ସମୟରେ ଅତିରିକ୍ତ ଶୁଳ୍କ ଲାଗୁ ହୋଇପାରେ"</string>
+</resources>
diff --git a/Tethering/res/values-mcc310-mnc004-pa/strings.xml b/Tethering/res/values-mcc310-mnc004-pa/strings.xml
new file mode 100644
index 0000000..819833e
--- /dev/null
+++ b/Tethering/res/values-mcc310-mnc004-pa/strings.xml
@@ -0,0 +1,24 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!--  Copyright (C) 2020 The Android Open Source Project
+
+     Licensed under the Apache License, Version 2.0 (the "License");
+     you may not use this file except in compliance with the License.
+     You may obtain a copy of the License at
+
+          http://www.apache.org/licenses/LICENSE-2.0
+
+     Unless required by applicable law or agreed to in writing, software
+     distributed under the License is distributed on an "AS IS" BASIS,
+     WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+     See the License for the specific language governing permissions and
+     limitations under the License.
+ -->
+
+<resources xmlns:android="http://schemas.android.com/apk/res/android"
+    xmlns:xliff="urn:oasis:names:tc:xliff:document:1.2">
+    <string name="no_upstream_notification_title" msgid="5030042590486713460">"ਟੈਦਰਿੰਗ ਕੋਲ ਇੰਟਰਨੈੱਟ ਪਹੁੰਚ ਨਹੀਂ ਹੈ"</string>
+    <string name="no_upstream_notification_message" msgid="3843613362272973447">"ਡੀਵਾਈਸ ਕਨੈਕਟ ਨਹੀਂ ਕੀਤੇ ਜਾ ਸਕਦੇ"</string>
+    <string name="no_upstream_notification_disable_button" msgid="6385491461813507624">"ਟੈਦਰਿੰਗ ਬੰਦ ਕਰੋ"</string>
+    <string name="upstream_roaming_notification_title" msgid="3015912166812283303">"ਹੌਟਸਪੌਟ ਜਾਂ ਟੈਦਰਿੰਗ ਚਾਲੂ ਹੈ"</string>
+    <string name="upstream_roaming_notification_message" msgid="6724434706748439902">"ਰੋਮਿੰਗ ਦੌਰਾਨ ਵਧੀਕ ਖਰਚੇ ਲਾਗੂ ਹੋ ਸਕਦੇ ਹਨ"</string>
+</resources>
diff --git a/Tethering/res/values-mcc310-mnc004-pl/strings.xml b/Tethering/res/values-mcc310-mnc004-pl/strings.xml
new file mode 100644
index 0000000..65e4380
--- /dev/null
+++ b/Tethering/res/values-mcc310-mnc004-pl/strings.xml
@@ -0,0 +1,24 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!--  Copyright (C) 2020 The Android Open Source Project
+
+     Licensed under the Apache License, Version 2.0 (the "License");
+     you may not use this file except in compliance with the License.
+     You may obtain a copy of the License at
+
+          http://www.apache.org/licenses/LICENSE-2.0
+
+     Unless required by applicable law or agreed to in writing, software
+     distributed under the License is distributed on an "AS IS" BASIS,
+     WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+     See the License for the specific language governing permissions and
+     limitations under the License.
+ -->
+
+<resources xmlns:android="http://schemas.android.com/apk/res/android"
+    xmlns:xliff="urn:oasis:names:tc:xliff:document:1.2">
+    <string name="no_upstream_notification_title" msgid="5030042590486713460">"Tethering nie ma internetu"</string>
+    <string name="no_upstream_notification_message" msgid="3843613362272973447">"Urządzenia nie mogą się połączyć"</string>
+    <string name="no_upstream_notification_disable_button" msgid="6385491461813507624">"Wyłącz tethering"</string>
+    <string name="upstream_roaming_notification_title" msgid="3015912166812283303">"Hotspot lub tethering jest włączony"</string>
+    <string name="upstream_roaming_notification_message" msgid="6724434706748439902">"Podczas korzystania z roamingu mogą zostać naliczone dodatkowe opłaty"</string>
+</resources>
diff --git a/Tethering/res/values-mcc310-mnc004-pt-rBR/strings.xml b/Tethering/res/values-mcc310-mnc004-pt-rBR/strings.xml
new file mode 100644
index 0000000..d886617
--- /dev/null
+++ b/Tethering/res/values-mcc310-mnc004-pt-rBR/strings.xml
@@ -0,0 +1,24 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!--  Copyright (C) 2020 The Android Open Source Project
+
+     Licensed under the Apache License, Version 2.0 (the "License");
+     you may not use this file except in compliance with the License.
+     You may obtain a copy of the License at
+
+          http://www.apache.org/licenses/LICENSE-2.0
+
+     Unless required by applicable law or agreed to in writing, software
+     distributed under the License is distributed on an "AS IS" BASIS,
+     WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+     See the License for the specific language governing permissions and
+     limitations under the License.
+ -->
+
+<resources xmlns:android="http://schemas.android.com/apk/res/android"
+    xmlns:xliff="urn:oasis:names:tc:xliff:document:1.2">
+    <string name="no_upstream_notification_title" msgid="5030042590486713460">"O tethering não tem Internet"</string>
+    <string name="no_upstream_notification_message" msgid="3843613362272973447">"Não é possível conectar os dispositivos"</string>
+    <string name="no_upstream_notification_disable_button" msgid="6385491461813507624">"Desativar o tethering"</string>
+    <string name="upstream_roaming_notification_title" msgid="3015912166812283303">"Ponto de acesso ou tethering ativado"</string>
+    <string name="upstream_roaming_notification_message" msgid="6724434706748439902">"Pode haver cobranças extras durante o roaming"</string>
+</resources>
diff --git a/Tethering/res/values-mcc310-mnc004-pt-rPT/strings.xml b/Tethering/res/values-mcc310-mnc004-pt-rPT/strings.xml
new file mode 100644
index 0000000..bfd45ca
--- /dev/null
+++ b/Tethering/res/values-mcc310-mnc004-pt-rPT/strings.xml
@@ -0,0 +1,24 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!--  Copyright (C) 2020 The Android Open Source Project
+
+     Licensed under the Apache License, Version 2.0 (the "License");
+     you may not use this file except in compliance with the License.
+     You may obtain a copy of the License at
+
+          http://www.apache.org/licenses/LICENSE-2.0
+
+     Unless required by applicable law or agreed to in writing, software
+     distributed under the License is distributed on an "AS IS" BASIS,
+     WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+     See the License for the specific language governing permissions and
+     limitations under the License.
+ -->
+
+<resources xmlns:android="http://schemas.android.com/apk/res/android"
+    xmlns:xliff="urn:oasis:names:tc:xliff:document:1.2">
+    <string name="no_upstream_notification_title" msgid="5030042590486713460">"A ligação (à Internet) via telemóvel não tem Internet"</string>
+    <string name="no_upstream_notification_message" msgid="3843613362272973447">"Não é possível ligar os dispositivos"</string>
+    <string name="no_upstream_notification_disable_button" msgid="6385491461813507624">"Desativar ligação (à Internet) via telemóvel"</string>
+    <string name="upstream_roaming_notification_title" msgid="3015912166812283303">"A zona Wi-Fi ou a ligação (à Internet) via telemóvel está ativada"</string>
+    <string name="upstream_roaming_notification_message" msgid="6724434706748439902">"Podem aplicar-se custos adicionais em roaming."</string>
+</resources>
diff --git a/Tethering/res/values-mcc310-mnc004-pt/strings.xml b/Tethering/res/values-mcc310-mnc004-pt/strings.xml
new file mode 100644
index 0000000..d886617
--- /dev/null
+++ b/Tethering/res/values-mcc310-mnc004-pt/strings.xml
@@ -0,0 +1,24 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!--  Copyright (C) 2020 The Android Open Source Project
+
+     Licensed under the Apache License, Version 2.0 (the "License");
+     you may not use this file except in compliance with the License.
+     You may obtain a copy of the License at
+
+          http://www.apache.org/licenses/LICENSE-2.0
+
+     Unless required by applicable law or agreed to in writing, software
+     distributed under the License is distributed on an "AS IS" BASIS,
+     WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+     See the License for the specific language governing permissions and
+     limitations under the License.
+ -->
+
+<resources xmlns:android="http://schemas.android.com/apk/res/android"
+    xmlns:xliff="urn:oasis:names:tc:xliff:document:1.2">
+    <string name="no_upstream_notification_title" msgid="5030042590486713460">"O tethering não tem Internet"</string>
+    <string name="no_upstream_notification_message" msgid="3843613362272973447">"Não é possível conectar os dispositivos"</string>
+    <string name="no_upstream_notification_disable_button" msgid="6385491461813507624">"Desativar o tethering"</string>
+    <string name="upstream_roaming_notification_title" msgid="3015912166812283303">"Ponto de acesso ou tethering ativado"</string>
+    <string name="upstream_roaming_notification_message" msgid="6724434706748439902">"Pode haver cobranças extras durante o roaming"</string>
+</resources>
diff --git a/Tethering/res/values-mcc310-mnc004-ro/strings.xml b/Tethering/res/values-mcc310-mnc004-ro/strings.xml
new file mode 100644
index 0000000..8d87a9e
--- /dev/null
+++ b/Tethering/res/values-mcc310-mnc004-ro/strings.xml
@@ -0,0 +1,24 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!--  Copyright (C) 2020 The Android Open Source Project
+
+     Licensed under the Apache License, Version 2.0 (the "License");
+     you may not use this file except in compliance with the License.
+     You may obtain a copy of the License at
+
+          http://www.apache.org/licenses/LICENSE-2.0
+
+     Unless required by applicable law or agreed to in writing, software
+     distributed under the License is distributed on an "AS IS" BASIS,
+     WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+     See the License for the specific language governing permissions and
+     limitations under the License.
+ -->
+
+<resources xmlns:android="http://schemas.android.com/apk/res/android"
+    xmlns:xliff="urn:oasis:names:tc:xliff:document:1.2">
+    <string name="no_upstream_notification_title" msgid="5030042590486713460">"Procesul de tethering nu are internet"</string>
+    <string name="no_upstream_notification_message" msgid="3843613362272973447">"Dispozitivele nu se pot conecta"</string>
+    <string name="no_upstream_notification_disable_button" msgid="6385491461813507624">"Dezactivați procesul de tethering"</string>
+    <string name="upstream_roaming_notification_title" msgid="3015912166812283303">"S-a activat hotspotul sau tethering"</string>
+    <string name="upstream_roaming_notification_message" msgid="6724434706748439902">"Se pot aplica taxe suplimentare pentru roaming"</string>
+</resources>
diff --git a/Tethering/res/values-mcc310-mnc004-ru/strings.xml b/Tethering/res/values-mcc310-mnc004-ru/strings.xml
new file mode 100644
index 0000000..dbdb9eb
--- /dev/null
+++ b/Tethering/res/values-mcc310-mnc004-ru/strings.xml
@@ -0,0 +1,24 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!--  Copyright (C) 2020 The Android Open Source Project
+
+     Licensed under the Apache License, Version 2.0 (the "License");
+     you may not use this file except in compliance with the License.
+     You may obtain a copy of the License at
+
+          http://www.apache.org/licenses/LICENSE-2.0
+
+     Unless required by applicable law or agreed to in writing, software
+     distributed under the License is distributed on an "AS IS" BASIS,
+     WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+     See the License for the specific language governing permissions and
+     limitations under the License.
+ -->
+
+<resources xmlns:android="http://schemas.android.com/apk/res/android"
+    xmlns:xliff="urn:oasis:names:tc:xliff:document:1.2">
+    <string name="no_upstream_notification_title" msgid="5030042590486713460">"Режим модема используется без доступа к Интернету"</string>
+    <string name="no_upstream_notification_message" msgid="3843613362272973447">"Невозможно подключить устройства."</string>
+    <string name="no_upstream_notification_disable_button" msgid="6385491461813507624">"Отключить режим модема"</string>
+    <string name="upstream_roaming_notification_title" msgid="3015912166812283303">"Включены точка доступа или режим модема"</string>
+    <string name="upstream_roaming_notification_message" msgid="6724434706748439902">"За использование услуг связи в роуминге может взиматься дополнительная плата."</string>
+</resources>
diff --git a/Tethering/res/values-mcc310-mnc004-si/strings.xml b/Tethering/res/values-mcc310-mnc004-si/strings.xml
new file mode 100644
index 0000000..d8301e4
--- /dev/null
+++ b/Tethering/res/values-mcc310-mnc004-si/strings.xml
@@ -0,0 +1,24 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!--  Copyright (C) 2020 The Android Open Source Project
+
+     Licensed under the Apache License, Version 2.0 (the "License");
+     you may not use this file except in compliance with the License.
+     You may obtain a copy of the License at
+
+          http://www.apache.org/licenses/LICENSE-2.0
+
+     Unless required by applicable law or agreed to in writing, software
+     distributed under the License is distributed on an "AS IS" BASIS,
+     WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+     See the License for the specific language governing permissions and
+     limitations under the License.
+ -->
+
+<resources xmlns:android="http://schemas.android.com/apk/res/android"
+    xmlns:xliff="urn:oasis:names:tc:xliff:document:1.2">
+    <string name="no_upstream_notification_title" msgid="5030042590486713460">"ටෙදරින් හට අන්තර්ජාලය නැත"</string>
+    <string name="no_upstream_notification_message" msgid="3843613362272973447">"උපාංගවලට සම්බන්ධ විය නොහැකිය"</string>
+    <string name="no_upstream_notification_disable_button" msgid="6385491461813507624">"ටෙදරින් ක්‍රියාවිරහිත කරන්න"</string>
+    <string name="upstream_roaming_notification_title" msgid="3015912166812283303">"හොට්ස්පොට් හෝ ටෙදරින් ක්‍රියාත්මකයි"</string>
+    <string name="upstream_roaming_notification_message" msgid="6724434706748439902">"රෝමිං අතරතුර අමතර ගාස්තු අදාළ විය හැකිය"</string>
+</resources>
diff --git a/Tethering/res/values-mcc310-mnc004-sk/strings.xml b/Tethering/res/values-mcc310-mnc004-sk/strings.xml
new file mode 100644
index 0000000..bef7136
--- /dev/null
+++ b/Tethering/res/values-mcc310-mnc004-sk/strings.xml
@@ -0,0 +1,24 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!--  Copyright (C) 2020 The Android Open Source Project
+
+     Licensed under the Apache License, Version 2.0 (the "License");
+     you may not use this file except in compliance with the License.
+     You may obtain a copy of the License at
+
+          http://www.apache.org/licenses/LICENSE-2.0
+
+     Unless required by applicable law or agreed to in writing, software
+     distributed under the License is distributed on an "AS IS" BASIS,
+     WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+     See the License for the specific language governing permissions and
+     limitations under the License.
+ -->
+
+<resources xmlns:android="http://schemas.android.com/apk/res/android"
+    xmlns:xliff="urn:oasis:names:tc:xliff:document:1.2">
+    <string name="no_upstream_notification_title" msgid="5030042590486713460">"Tethering nemá internetové pripojenie"</string>
+    <string name="no_upstream_notification_message" msgid="3843613362272973447">"Zariadenia sa nemôžu pripojiť"</string>
+    <string name="no_upstream_notification_disable_button" msgid="6385491461813507624">"Vypnúť tethering"</string>
+    <string name="upstream_roaming_notification_title" msgid="3015912166812283303">"Je zapnutý hotspot alebo tethering"</string>
+    <string name="upstream_roaming_notification_message" msgid="6724434706748439902">"Počas roamingu vám môžu byť účtované ďalšie poplatky"</string>
+</resources>
diff --git a/Tethering/res/values-mcc310-mnc004-sl/strings.xml b/Tethering/res/values-mcc310-mnc004-sl/strings.xml
new file mode 100644
index 0000000..3202c62
--- /dev/null
+++ b/Tethering/res/values-mcc310-mnc004-sl/strings.xml
@@ -0,0 +1,24 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!--  Copyright (C) 2020 The Android Open Source Project
+
+     Licensed under the Apache License, Version 2.0 (the "License");
+     you may not use this file except in compliance with the License.
+     You may obtain a copy of the License at
+
+          http://www.apache.org/licenses/LICENSE-2.0
+
+     Unless required by applicable law or agreed to in writing, software
+     distributed under the License is distributed on an "AS IS" BASIS,
+     WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+     See the License for the specific language governing permissions and
+     limitations under the License.
+ -->
+
+<resources xmlns:android="http://schemas.android.com/apk/res/android"
+    xmlns:xliff="urn:oasis:names:tc:xliff:document:1.2">
+    <string name="no_upstream_notification_title" msgid="5030042590486713460">"Internetna povezava prek mobilnega telefona ni vzpostavljena"</string>
+    <string name="no_upstream_notification_message" msgid="3843613362272973447">"Napravi se ne moreta povezati"</string>
+    <string name="no_upstream_notification_disable_button" msgid="6385491461813507624">"Izklopi internetno povezavo prek mobilnega telefona"</string>
+    <string name="upstream_roaming_notification_title" msgid="3015912166812283303">"Dostopna točka ali internetna povezava prek mobilnega telefona je vklopljena"</string>
+    <string name="upstream_roaming_notification_message" msgid="6724434706748439902">"Med gostovanjem lahko nastanejo dodatni stroški"</string>
+</resources>
diff --git a/Tethering/res/values-mcc310-mnc004-sq/strings.xml b/Tethering/res/values-mcc310-mnc004-sq/strings.xml
new file mode 100644
index 0000000..37f6ad2
--- /dev/null
+++ b/Tethering/res/values-mcc310-mnc004-sq/strings.xml
@@ -0,0 +1,24 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!--  Copyright (C) 2020 The Android Open Source Project
+
+     Licensed under the Apache License, Version 2.0 (the "License");
+     you may not use this file except in compliance with the License.
+     You may obtain a copy of the License at
+
+          http://www.apache.org/licenses/LICENSE-2.0
+
+     Unless required by applicable law or agreed to in writing, software
+     distributed under the License is distributed on an "AS IS" BASIS,
+     WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+     See the License for the specific language governing permissions and
+     limitations under the License.
+ -->
+
+<resources xmlns:android="http://schemas.android.com/apk/res/android"
+    xmlns:xliff="urn:oasis:names:tc:xliff:document:1.2">
+    <string name="no_upstream_notification_title" msgid="5030042590486713460">"Ndarja e internetit nuk ka internet"</string>
+    <string name="no_upstream_notification_message" msgid="3843613362272973447">"Pajisjet nuk mund të lidhen"</string>
+    <string name="no_upstream_notification_disable_button" msgid="6385491461813507624">"Çaktivizo ndarjen e internetit"</string>
+    <string name="upstream_roaming_notification_title" msgid="3015912166812283303">"Zona e qasjes për internet ose ndarja e internetit është aktive"</string>
+    <string name="upstream_roaming_notification_message" msgid="6724434706748439902">"Mund të zbatohen tarifime shtesë kur je në roaming"</string>
+</resources>
diff --git a/Tethering/res/values-mcc310-mnc004-sr/strings.xml b/Tethering/res/values-mcc310-mnc004-sr/strings.xml
new file mode 100644
index 0000000..5566d03
--- /dev/null
+++ b/Tethering/res/values-mcc310-mnc004-sr/strings.xml
@@ -0,0 +1,24 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!--  Copyright (C) 2020 The Android Open Source Project
+
+     Licensed under the Apache License, Version 2.0 (the "License");
+     you may not use this file except in compliance with the License.
+     You may obtain a copy of the License at
+
+          http://www.apache.org/licenses/LICENSE-2.0
+
+     Unless required by applicable law or agreed to in writing, software
+     distributed under the License is distributed on an "AS IS" BASIS,
+     WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+     See the License for the specific language governing permissions and
+     limitations under the License.
+ -->
+
+<resources xmlns:android="http://schemas.android.com/apk/res/android"
+    xmlns:xliff="urn:oasis:names:tc:xliff:document:1.2">
+    <string name="no_upstream_notification_title" msgid="5030042590486713460">"Привезивање нема приступ интернету"</string>
+    <string name="no_upstream_notification_message" msgid="3843613362272973447">"Повезивање уређаја није успело"</string>
+    <string name="no_upstream_notification_disable_button" msgid="6385491461813507624">"Искључи привезивање"</string>
+    <string name="upstream_roaming_notification_title" msgid="3015912166812283303">"Укључен је хотспот или привезивање"</string>
+    <string name="upstream_roaming_notification_message" msgid="6724434706748439902">"Можда важе додатни трошкови у ромингу"</string>
+</resources>
diff --git a/Tethering/res/values-mcc310-mnc004-sv/strings.xml b/Tethering/res/values-mcc310-mnc004-sv/strings.xml
new file mode 100644
index 0000000..9765acd
--- /dev/null
+++ b/Tethering/res/values-mcc310-mnc004-sv/strings.xml
@@ -0,0 +1,24 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!--  Copyright (C) 2020 The Android Open Source Project
+
+     Licensed under the Apache License, Version 2.0 (the "License");
+     you may not use this file except in compliance with the License.
+     You may obtain a copy of the License at
+
+          http://www.apache.org/licenses/LICENSE-2.0
+
+     Unless required by applicable law or agreed to in writing, software
+     distributed under the License is distributed on an "AS IS" BASIS,
+     WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+     See the License for the specific language governing permissions and
+     limitations under the License.
+ -->
+
+<resources xmlns:android="http://schemas.android.com/apk/res/android"
+    xmlns:xliff="urn:oasis:names:tc:xliff:document:1.2">
+    <string name="no_upstream_notification_title" msgid="5030042590486713460">"Det finns ingen internetanslutning för internetdelningen"</string>
+    <string name="no_upstream_notification_message" msgid="3843613362272973447">"Enheterna kan inte anslutas"</string>
+    <string name="no_upstream_notification_disable_button" msgid="6385491461813507624">"Inaktivera internetdelning"</string>
+    <string name="upstream_roaming_notification_title" msgid="3015912166812283303">"Surfzon eller internetdelning har aktiverats"</string>
+    <string name="upstream_roaming_notification_message" msgid="6724434706748439902">"Ytterligare avgifter kan tillkomma vid roaming"</string>
+</resources>
diff --git a/Tethering/res/values-mcc310-mnc004-sw/strings.xml b/Tethering/res/values-mcc310-mnc004-sw/strings.xml
new file mode 100644
index 0000000..cf850c9
--- /dev/null
+++ b/Tethering/res/values-mcc310-mnc004-sw/strings.xml
@@ -0,0 +1,24 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!--  Copyright (C) 2020 The Android Open Source Project
+
+     Licensed under the Apache License, Version 2.0 (the "License");
+     you may not use this file except in compliance with the License.
+     You may obtain a copy of the License at
+
+          http://www.apache.org/licenses/LICENSE-2.0
+
+     Unless required by applicable law or agreed to in writing, software
+     distributed under the License is distributed on an "AS IS" BASIS,
+     WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+     See the License for the specific language governing permissions and
+     limitations under the License.
+ -->
+
+<resources xmlns:android="http://schemas.android.com/apk/res/android"
+    xmlns:xliff="urn:oasis:names:tc:xliff:document:1.2">
+    <string name="no_upstream_notification_title" msgid="5030042590486713460">"Kipengele cha kusambaza mtandao hakina intaneti"</string>
+    <string name="no_upstream_notification_message" msgid="3843613362272973447">"Imeshindwa kuunganisha vifaa"</string>
+    <string name="no_upstream_notification_disable_button" msgid="6385491461813507624">"Zima kipengele cha kusambaza mtandao"</string>
+    <string name="upstream_roaming_notification_title" msgid="3015912166812283303">"Umewasha kipengele cha kusambaza mtandao au mtandao pepe"</string>
+    <string name="upstream_roaming_notification_message" msgid="6724434706748439902">"Huenda ukatozwa gharama za ziada ukitumia mitandao ya ng\'ambo"</string>
+</resources>
diff --git a/Tethering/res/values-mcc310-mnc004-ta/strings.xml b/Tethering/res/values-mcc310-mnc004-ta/strings.xml
new file mode 100644
index 0000000..f4b15aa
--- /dev/null
+++ b/Tethering/res/values-mcc310-mnc004-ta/strings.xml
@@ -0,0 +1,24 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!--  Copyright (C) 2020 The Android Open Source Project
+
+     Licensed under the Apache License, Version 2.0 (the "License");
+     you may not use this file except in compliance with the License.
+     You may obtain a copy of the License at
+
+          http://www.apache.org/licenses/LICENSE-2.0
+
+     Unless required by applicable law or agreed to in writing, software
+     distributed under the License is distributed on an "AS IS" BASIS,
+     WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+     See the License for the specific language governing permissions and
+     limitations under the License.
+ -->
+
+<resources xmlns:android="http://schemas.android.com/apk/res/android"
+    xmlns:xliff="urn:oasis:names:tc:xliff:document:1.2">
+    <string name="no_upstream_notification_title" msgid="5030042590486713460">"இணைப்பு முறைக்கு இணைய இணைப்பு இல்லை"</string>
+    <string name="no_upstream_notification_message" msgid="3843613362272973447">"சாதனங்களால் இணைய முடியவில்லை"</string>
+    <string name="no_upstream_notification_disable_button" msgid="6385491461813507624">"இணைப்பு முறையை ஆஃப் செய்"</string>
+    <string name="upstream_roaming_notification_title" msgid="3015912166812283303">"ஹாட்ஸ்பாட் அல்லது இணைப்பு முறை ஆன் செய்யப்பட்டுள்ளது"</string>
+    <string name="upstream_roaming_notification_message" msgid="6724434706748439902">"ரோமிங்கின்போது கூடுதல் கட்டணங்கள் விதிக்கப்படக்கூடும்"</string>
+</resources>
diff --git a/Tethering/res/values-mcc310-mnc004-te/strings.xml b/Tethering/res/values-mcc310-mnc004-te/strings.xml
new file mode 100644
index 0000000..937d34d
--- /dev/null
+++ b/Tethering/res/values-mcc310-mnc004-te/strings.xml
@@ -0,0 +1,24 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!--  Copyright (C) 2020 The Android Open Source Project
+
+     Licensed under the Apache License, Version 2.0 (the "License");
+     you may not use this file except in compliance with the License.
+     You may obtain a copy of the License at
+
+          http://www.apache.org/licenses/LICENSE-2.0
+
+     Unless required by applicable law or agreed to in writing, software
+     distributed under the License is distributed on an "AS IS" BASIS,
+     WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+     See the License for the specific language governing permissions and
+     limitations under the License.
+ -->
+
+<resources xmlns:android="http://schemas.android.com/apk/res/android"
+    xmlns:xliff="urn:oasis:names:tc:xliff:document:1.2">
+    <string name="no_upstream_notification_title" msgid="5030042590486713460">"టెథరింగ్ చేయడానికి ఇంటర్నెట్ కనెక్షన్ లేదు"</string>
+    <string name="no_upstream_notification_message" msgid="3843613362272973447">"పరికరాలు కనెక్ట్ అవ్వడం లేదు"</string>
+    <string name="no_upstream_notification_disable_button" msgid="6385491461813507624">"టెథరింగ్‌ను ఆఫ్ చేయండి"</string>
+    <string name="upstream_roaming_notification_title" msgid="3015912166812283303">"హాట్‌స్పాట్ లేదా టెథరింగ్ ఆన్‌లో ఉంది"</string>
+    <string name="upstream_roaming_notification_message" msgid="6724434706748439902">"రోమింగ్‌లో ఉన్నప్పుడు అదనపు ఛార్జీలు వర్తించవచ్చు"</string>
+</resources>
diff --git a/Tethering/res/values-mcc310-mnc004-th/strings.xml b/Tethering/res/values-mcc310-mnc004-th/strings.xml
new file mode 100644
index 0000000..f781fae
--- /dev/null
+++ b/Tethering/res/values-mcc310-mnc004-th/strings.xml
@@ -0,0 +1,24 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!--  Copyright (C) 2020 The Android Open Source Project
+
+     Licensed under the Apache License, Version 2.0 (the "License");
+     you may not use this file except in compliance with the License.
+     You may obtain a copy of the License at
+
+          http://www.apache.org/licenses/LICENSE-2.0
+
+     Unless required by applicable law or agreed to in writing, software
+     distributed under the License is distributed on an "AS IS" BASIS,
+     WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+     See the License for the specific language governing permissions and
+     limitations under the License.
+ -->
+
+<resources xmlns:android="http://schemas.android.com/apk/res/android"
+    xmlns:xliff="urn:oasis:names:tc:xliff:document:1.2">
+    <string name="no_upstream_notification_title" msgid="5030042590486713460">"การเชื่อมต่ออินเทอร์เน็ตผ่านมือถือไม่มีอินเทอร์เน็ต"</string>
+    <string name="no_upstream_notification_message" msgid="3843613362272973447">"อุปกรณ์เชื่อมต่อไม่ได้"</string>
+    <string name="no_upstream_notification_disable_button" msgid="6385491461813507624">"ปิดการเชื่อมต่ออินเทอร์เน็ตผ่านมือถือ"</string>
+    <string name="upstream_roaming_notification_title" msgid="3015912166812283303">"ฮอตสปอตหรือการเชื่อมต่ออินเทอร์เน็ตผ่านมือถือเปิดอยู่"</string>
+    <string name="upstream_roaming_notification_message" msgid="6724434706748439902">"อาจมีค่าใช้จ่ายเพิ่มเติมขณะโรมมิ่ง"</string>
+</resources>
diff --git a/Tethering/res/values-mcc310-mnc004-tl/strings.xml b/Tethering/res/values-mcc310-mnc004-tl/strings.xml
new file mode 100644
index 0000000..8d5d465
--- /dev/null
+++ b/Tethering/res/values-mcc310-mnc004-tl/strings.xml
@@ -0,0 +1,24 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!--  Copyright (C) 2020 The Android Open Source Project
+
+     Licensed under the Apache License, Version 2.0 (the "License");
+     you may not use this file except in compliance with the License.
+     You may obtain a copy of the License at
+
+          http://www.apache.org/licenses/LICENSE-2.0
+
+     Unless required by applicable law or agreed to in writing, software
+     distributed under the License is distributed on an "AS IS" BASIS,
+     WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+     See the License for the specific language governing permissions and
+     limitations under the License.
+ -->
+
+<resources xmlns:android="http://schemas.android.com/apk/res/android"
+    xmlns:xliff="urn:oasis:names:tc:xliff:document:1.2">
+    <string name="no_upstream_notification_title" msgid="5030042590486713460">"Walang internet ang pag-tether"</string>
+    <string name="no_upstream_notification_message" msgid="3843613362272973447">"Hindi makakonekta ang mga device"</string>
+    <string name="no_upstream_notification_disable_button" msgid="6385491461813507624">"I-off ang pag-tether"</string>
+    <string name="upstream_roaming_notification_title" msgid="3015912166812283303">"Naka-on ang Hotspot o pag-tether"</string>
+    <string name="upstream_roaming_notification_message" msgid="6724434706748439902">"Posibleng magkaroon ng mga karagdagang singil habang nagro-roam"</string>
+</resources>
diff --git a/Tethering/res/values-mcc310-mnc004-tr/strings.xml b/Tethering/res/values-mcc310-mnc004-tr/strings.xml
new file mode 100644
index 0000000..80cab33
--- /dev/null
+++ b/Tethering/res/values-mcc310-mnc004-tr/strings.xml
@@ -0,0 +1,24 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!--  Copyright (C) 2020 The Android Open Source Project
+
+     Licensed under the Apache License, Version 2.0 (the "License");
+     you may not use this file except in compliance with the License.
+     You may obtain a copy of the License at
+
+          http://www.apache.org/licenses/LICENSE-2.0
+
+     Unless required by applicable law or agreed to in writing, software
+     distributed under the License is distributed on an "AS IS" BASIS,
+     WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+     See the License for the specific language governing permissions and
+     limitations under the License.
+ -->
+
+<resources xmlns:android="http://schemas.android.com/apk/res/android"
+    xmlns:xliff="urn:oasis:names:tc:xliff:document:1.2">
+    <string name="no_upstream_notification_title" msgid="5030042590486713460">"Tethering\'in internet bağlantısı yok"</string>
+    <string name="no_upstream_notification_message" msgid="3843613362272973447">"Cihazlar bağlanamıyor"</string>
+    <string name="no_upstream_notification_disable_button" msgid="6385491461813507624">"Tethering\'i kapat"</string>
+    <string name="upstream_roaming_notification_title" msgid="3015912166812283303">"Hotspot veya tethering açık"</string>
+    <string name="upstream_roaming_notification_message" msgid="6724434706748439902">"Dolaşım sırasında ek ücretler uygulanabilir"</string>
+</resources>
diff --git a/Tethering/res/values-mcc310-mnc004-uk/strings.xml b/Tethering/res/values-mcc310-mnc004-uk/strings.xml
new file mode 100644
index 0000000..c05932a
--- /dev/null
+++ b/Tethering/res/values-mcc310-mnc004-uk/strings.xml
@@ -0,0 +1,24 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!--  Copyright (C) 2020 The Android Open Source Project
+
+     Licensed under the Apache License, Version 2.0 (the "License");
+     you may not use this file except in compliance with the License.
+     You may obtain a copy of the License at
+
+          http://www.apache.org/licenses/LICENSE-2.0
+
+     Unless required by applicable law or agreed to in writing, software
+     distributed under the License is distributed on an "AS IS" BASIS,
+     WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+     See the License for the specific language governing permissions and
+     limitations under the License.
+ -->
+
+<resources xmlns:android="http://schemas.android.com/apk/res/android"
+    xmlns:xliff="urn:oasis:names:tc:xliff:document:1.2">
+    <string name="no_upstream_notification_title" msgid="5030042590486713460">"Телефон, який використовується як модем, не підключений до Інтернету"</string>
+    <string name="no_upstream_notification_message" msgid="3843613362272973447">"Не вдається підключити пристрої"</string>
+    <string name="no_upstream_notification_disable_button" msgid="6385491461813507624">"Вимкнути використання телефона як модема"</string>
+    <string name="upstream_roaming_notification_title" msgid="3015912166812283303">"Увімкнено точку доступу або використання телефона як модема"</string>
+    <string name="upstream_roaming_notification_message" msgid="6724434706748439902">"У роумінгу може стягуватися додаткова плата"</string>
+</resources>
diff --git a/Tethering/res/values-mcc310-mnc004-ur/strings.xml b/Tethering/res/values-mcc310-mnc004-ur/strings.xml
new file mode 100644
index 0000000..d820eee
--- /dev/null
+++ b/Tethering/res/values-mcc310-mnc004-ur/strings.xml
@@ -0,0 +1,24 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!--  Copyright (C) 2020 The Android Open Source Project
+
+     Licensed under the Apache License, Version 2.0 (the "License");
+     you may not use this file except in compliance with the License.
+     You may obtain a copy of the License at
+
+          http://www.apache.org/licenses/LICENSE-2.0
+
+     Unless required by applicable law or agreed to in writing, software
+     distributed under the License is distributed on an "AS IS" BASIS,
+     WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+     See the License for the specific language governing permissions and
+     limitations under the License.
+ -->
+
+<resources xmlns:android="http://schemas.android.com/apk/res/android"
+    xmlns:xliff="urn:oasis:names:tc:xliff:document:1.2">
+    <string name="no_upstream_notification_title" msgid="5030042590486713460">"ٹیدرنگ میں انٹرنیٹ نہیں ہے"</string>
+    <string name="no_upstream_notification_message" msgid="3843613362272973447">"آلات منسلک نہیں ہو سکتے"</string>
+    <string name="no_upstream_notification_disable_button" msgid="6385491461813507624">"ٹیدرنگ آف کریں"</string>
+    <string name="upstream_roaming_notification_title" msgid="3015912166812283303">"ہاٹ اسپاٹ یا ٹیدرنگ آن ہے"</string>
+    <string name="upstream_roaming_notification_message" msgid="6724434706748439902">"رومنگ کے دوران اضافی چارجز لاگو ہو سکتے ہیں"</string>
+</resources>
diff --git a/Tethering/res/values-mcc310-mnc004-uz/strings.xml b/Tethering/res/values-mcc310-mnc004-uz/strings.xml
new file mode 100644
index 0000000..726148a
--- /dev/null
+++ b/Tethering/res/values-mcc310-mnc004-uz/strings.xml
@@ -0,0 +1,24 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!--  Copyright (C) 2020 The Android Open Source Project
+
+     Licensed under the Apache License, Version 2.0 (the "License");
+     you may not use this file except in compliance with the License.
+     You may obtain a copy of the License at
+
+          http://www.apache.org/licenses/LICENSE-2.0
+
+     Unless required by applicable law or agreed to in writing, software
+     distributed under the License is distributed on an "AS IS" BASIS,
+     WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+     See the License for the specific language governing permissions and
+     limitations under the License.
+ -->
+
+<resources xmlns:android="http://schemas.android.com/apk/res/android"
+    xmlns:xliff="urn:oasis:names:tc:xliff:document:1.2">
+    <string name="no_upstream_notification_title" msgid="5030042590486713460">"Modem internetga ulanmagan"</string>
+    <string name="no_upstream_notification_message" msgid="3843613362272973447">"Qurilmalar ulanmadi"</string>
+    <string name="no_upstream_notification_disable_button" msgid="6385491461813507624">"Modem rejimini faolsizlantirish"</string>
+    <string name="upstream_roaming_notification_title" msgid="3015912166812283303">"Hotspot yoki modem rejimi yoniq"</string>
+    <string name="upstream_roaming_notification_message" msgid="6724434706748439902">"Rouming vaqtida qoʻshimcha haq olinishi mumkin"</string>
+</resources>
diff --git a/Tethering/res/values-mcc310-mnc004-vi/strings.xml b/Tethering/res/values-mcc310-mnc004-vi/strings.xml
new file mode 100644
index 0000000..b7cb045
--- /dev/null
+++ b/Tethering/res/values-mcc310-mnc004-vi/strings.xml
@@ -0,0 +1,24 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!--  Copyright (C) 2020 The Android Open Source Project
+
+     Licensed under the Apache License, Version 2.0 (the "License");
+     you may not use this file except in compliance with the License.
+     You may obtain a copy of the License at
+
+          http://www.apache.org/licenses/LICENSE-2.0
+
+     Unless required by applicable law or agreed to in writing, software
+     distributed under the License is distributed on an "AS IS" BASIS,
+     WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+     See the License for the specific language governing permissions and
+     limitations under the License.
+ -->
+
+<resources xmlns:android="http://schemas.android.com/apk/res/android"
+    xmlns:xliff="urn:oasis:names:tc:xliff:document:1.2">
+    <string name="no_upstream_notification_title" msgid="5030042590486713460">"Không có Internet để chia sẻ kết Internet"</string>
+    <string name="no_upstream_notification_message" msgid="3843613362272973447">"Các thiết bị không thể kết nối"</string>
+    <string name="no_upstream_notification_disable_button" msgid="6385491461813507624">"Tắt tính năng chia sẻ Internet"</string>
+    <string name="upstream_roaming_notification_title" msgid="3015912166812283303">"Điểm phát sóng hoặc tính năng chia sẻ Internet đang bật"</string>
+    <string name="upstream_roaming_notification_message" msgid="6724434706748439902">"Bạn có thể mất thêm phí dữ liệu khi chuyển vùng"</string>
+</resources>
diff --git a/Tethering/res/values-mcc310-mnc004-zh-rCN/strings.xml b/Tethering/res/values-mcc310-mnc004-zh-rCN/strings.xml
new file mode 100644
index 0000000..af91aff
--- /dev/null
+++ b/Tethering/res/values-mcc310-mnc004-zh-rCN/strings.xml
@@ -0,0 +1,24 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!--  Copyright (C) 2020 The Android Open Source Project
+
+     Licensed under the Apache License, Version 2.0 (the "License");
+     you may not use this file except in compliance with the License.
+     You may obtain a copy of the License at
+
+          http://www.apache.org/licenses/LICENSE-2.0
+
+     Unless required by applicable law or agreed to in writing, software
+     distributed under the License is distributed on an "AS IS" BASIS,
+     WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+     See the License for the specific language governing permissions and
+     limitations under the License.
+ -->
+
+<resources xmlns:android="http://schemas.android.com/apk/res/android"
+    xmlns:xliff="urn:oasis:names:tc:xliff:document:1.2">
+    <string name="no_upstream_notification_title" msgid="5030042590486713460">"共享网络未连接到互联网"</string>
+    <string name="no_upstream_notification_message" msgid="3843613362272973447">"设备无法连接"</string>
+    <string name="no_upstream_notification_disable_button" msgid="6385491461813507624">"关闭网络共享"</string>
+    <string name="upstream_roaming_notification_title" msgid="3015912166812283303">"热点或网络共享已开启"</string>
+    <string name="upstream_roaming_notification_message" msgid="6724434706748439902">"漫游时可能会产生额外的费用"</string>
+</resources>
diff --git a/Tethering/res/values-mcc310-mnc004-zh-rHK/strings.xml b/Tethering/res/values-mcc310-mnc004-zh-rHK/strings.xml
new file mode 100644
index 0000000..28e6b80
--- /dev/null
+++ b/Tethering/res/values-mcc310-mnc004-zh-rHK/strings.xml
@@ -0,0 +1,24 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!--  Copyright (C) 2020 The Android Open Source Project
+
+     Licensed under the Apache License, Version 2.0 (the "License");
+     you may not use this file except in compliance with the License.
+     You may obtain a copy of the License at
+
+          http://www.apache.org/licenses/LICENSE-2.0
+
+     Unless required by applicable law or agreed to in writing, software
+     distributed under the License is distributed on an "AS IS" BASIS,
+     WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+     See the License for the specific language governing permissions and
+     limitations under the License.
+ -->
+
+<resources xmlns:android="http://schemas.android.com/apk/res/android"
+    xmlns:xliff="urn:oasis:names:tc:xliff:document:1.2">
+    <string name="no_upstream_notification_title" msgid="5030042590486713460">"無法透過網絡共享連線至互聯網"</string>
+    <string name="no_upstream_notification_message" msgid="3843613362272973447">"裝置無法連接"</string>
+    <string name="no_upstream_notification_disable_button" msgid="6385491461813507624">"關閉網絡共享"</string>
+    <string name="upstream_roaming_notification_title" msgid="3015912166812283303">"熱點或網絡共享已開啟"</string>
+    <string name="upstream_roaming_notification_message" msgid="6724434706748439902">"漫遊時可能需要支付額外費用"</string>
+</resources>
diff --git a/Tethering/res/values-mcc310-mnc004-zh-rTW/strings.xml b/Tethering/res/values-mcc310-mnc004-zh-rTW/strings.xml
new file mode 100644
index 0000000..528a1e5
--- /dev/null
+++ b/Tethering/res/values-mcc310-mnc004-zh-rTW/strings.xml
@@ -0,0 +1,24 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!--  Copyright (C) 2020 The Android Open Source Project
+
+     Licensed under the Apache License, Version 2.0 (the "License");
+     you may not use this file except in compliance with the License.
+     You may obtain a copy of the License at
+
+          http://www.apache.org/licenses/LICENSE-2.0
+
+     Unless required by applicable law or agreed to in writing, software
+     distributed under the License is distributed on an "AS IS" BASIS,
+     WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+     See the License for the specific language governing permissions and
+     limitations under the License.
+ -->
+
+<resources xmlns:android="http://schemas.android.com/apk/res/android"
+    xmlns:xliff="urn:oasis:names:tc:xliff:document:1.2">
+    <string name="no_upstream_notification_title" msgid="5030042590486713460">"無法透過網路共用連上網際網路"</string>
+    <string name="no_upstream_notification_message" msgid="3843613362272973447">"裝置無法連線"</string>
+    <string name="no_upstream_notification_disable_button" msgid="6385491461813507624">"關閉網路共用"</string>
+    <string name="upstream_roaming_notification_title" msgid="3015912166812283303">"無線基地台或網路共用已開啟"</string>
+    <string name="upstream_roaming_notification_message" msgid="6724434706748439902">"使用漫遊服務可能須支付額外費用"</string>
+</resources>
diff --git a/Tethering/res/values-mcc310-mnc004-zu/strings.xml b/Tethering/res/values-mcc310-mnc004-zu/strings.xml
new file mode 100644
index 0000000..11eb666
--- /dev/null
+++ b/Tethering/res/values-mcc310-mnc004-zu/strings.xml
@@ -0,0 +1,24 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!--  Copyright (C) 2020 The Android Open Source Project
+
+     Licensed under the Apache License, Version 2.0 (the "License");
+     you may not use this file except in compliance with the License.
+     You may obtain a copy of the License at
+
+          http://www.apache.org/licenses/LICENSE-2.0
+
+     Unless required by applicable law or agreed to in writing, software
+     distributed under the License is distributed on an "AS IS" BASIS,
+     WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+     See the License for the specific language governing permissions and
+     limitations under the License.
+ -->
+
+<resources xmlns:android="http://schemas.android.com/apk/res/android"
+    xmlns:xliff="urn:oasis:names:tc:xliff:document:1.2">
+    <string name="no_upstream_notification_title" msgid="5030042590486713460">"Ukusebenzisa ifoni njengemodemu akunayo i-inthanethi"</string>
+    <string name="no_upstream_notification_message" msgid="3843613362272973447">"Amadivayisi awakwazi ukuxhumeka"</string>
+    <string name="no_upstream_notification_disable_button" msgid="6385491461813507624">"Vala ukusebenzisa ifoni njengemodemu"</string>
+    <string name="upstream_roaming_notification_title" msgid="3015912166812283303">"I-hotspot noma ukusebenzisa ifoni njengemodemu kuvuliwe"</string>
+    <string name="upstream_roaming_notification_message" msgid="6724434706748439902">"Kungaba nezinkokhelo ezengeziwe uma uzula"</string>
+</resources>
diff --git a/Tethering/res/values-mcc310-mnc004/config.xml b/Tethering/res/values-mcc310-mnc004/config.xml
new file mode 100644
index 0000000..5c5be04
--- /dev/null
+++ b/Tethering/res/values-mcc310-mnc004/config.xml
@@ -0,0 +1,23 @@
+<?xml version="1.0" encoding="utf-8"?>
+<!-- Copyright (C) 2020 The Android Open Source Project
+
+     Licensed under the Apache License, Version 2.0 (the "License");
+     you may not use this file except in compliance with the License.
+     You may obtain a copy of the License at
+
+          http://www.apache.org/licenses/LICENSE-2.0
+
+     Unless required by applicable law or agreed to in writing, software
+     distributed under the License is distributed on an "AS IS" BASIS,
+     WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+     See the License for the specific language governing permissions and
+     limitations under the License.
+-->
+<resources>
+    <!-- Delay(millisecond) to show no upstream notification after there's no Backhaul. Set delay to
+         "0" for disable this feature. -->
+    <integer name="delay_to_show_no_upstream_after_no_backhaul">5000</integer>
+
+    <!-- Config for showing upstream roaming notification. -->
+    <bool name="config_upstream_roaming_notification">true</bool>
+</resources>
\ No newline at end of file
diff --git a/Tethering/res/values-mcc310-mnc004/strings.xml b/Tethering/res/values-mcc310-mnc004/strings.xml
new file mode 100644
index 0000000..ce9ff60
--- /dev/null
+++ b/Tethering/res/values-mcc310-mnc004/strings.xml
@@ -0,0 +1,28 @@
+<?xml version="1.0" encoding="utf-8"?>
+<!-- Copyright (C) 2020 The Android Open Source Project
+
+     Licensed under the Apache License, Version 2.0 (the "License");
+     you may not use this file except in compliance with the License.
+     You may obtain a copy of the License at
+
+          http://www.apache.org/licenses/LICENSE-2.0
+
+     Unless required by applicable law or agreed to in writing, software
+     distributed under the License is distributed on an "AS IS" BASIS,
+     WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+     See the License for the specific language governing permissions and
+     limitations under the License.
+-->
+<resources>
+    <!-- String for no upstream notification title [CHAR LIMIT=200] -->
+    <string name="no_upstream_notification_title">Tethering has no internet</string>
+    <!-- String for no upstream notification title [CHAR LIMIT=200] -->
+    <string name="no_upstream_notification_message">Devices can\u2019t connect</string>
+    <!-- String for no upstream notification disable button [CHAR LIMIT=200] -->
+    <string name="no_upstream_notification_disable_button">Turn off tethering</string>
+
+    <!-- String for cellular roaming notification title [CHAR LIMIT=200] -->
+    <string name="upstream_roaming_notification_title">Hotspot or tethering is on</string>
+    <!-- String for cellular roaming notification message [CHAR LIMIT=500] -->
+    <string name="upstream_roaming_notification_message">Additional charges may apply while roaming</string>
+</resources>
diff --git a/Tethering/res/values-mcc311-mnc480-af/strings.xml b/Tethering/res/values-mcc311-mnc480-af/strings.xml
new file mode 100644
index 0000000..9bfa531
--- /dev/null
+++ b/Tethering/res/values-mcc311-mnc480-af/strings.xml
@@ -0,0 +1,24 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!--  Copyright (C) 2020 The Android Open Source Project
+
+     Licensed under the Apache License, Version 2.0 (the "License");
+     you may not use this file except in compliance with the License.
+     You may obtain a copy of the License at
+
+          http://www.apache.org/licenses/LICENSE-2.0
+
+     Unless required by applicable law or agreed to in writing, software
+     distributed under the License is distributed on an "AS IS" BASIS,
+     WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+     See the License for the specific language governing permissions and
+     limitations under the License.
+ -->
+
+<resources xmlns:android="http://schemas.android.com/apk/res/android"
+    xmlns:xliff="urn:oasis:names:tc:xliff:document:1.2">
+    <string name="no_upstream_notification_title" msgid="611650570559011140">"Verbinding het nie internet nie"</string>
+    <string name="no_upstream_notification_message" msgid="6508394877641864863">"Toestelle kan nie koppel nie"</string>
+    <string name="no_upstream_notification_disable_button" msgid="7609346639290990508">"Skakel verbinding af"</string>
+    <string name="upstream_roaming_notification_title" msgid="6032901176124830787">"Warmkol of verbinding is aan"</string>
+    <string name="upstream_roaming_notification_message" msgid="7599056263326217523">"Bykomende heffings kan geld terwyl jy swerf"</string>
+</resources>
diff --git a/Tethering/res/values-mcc311-mnc480-am/strings.xml b/Tethering/res/values-mcc311-mnc480-am/strings.xml
new file mode 100644
index 0000000..5949dfa
--- /dev/null
+++ b/Tethering/res/values-mcc311-mnc480-am/strings.xml
@@ -0,0 +1,24 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!--  Copyright (C) 2020 The Android Open Source Project
+
+     Licensed under the Apache License, Version 2.0 (the "License");
+     you may not use this file except in compliance with the License.
+     You may obtain a copy of the License at
+
+          http://www.apache.org/licenses/LICENSE-2.0
+
+     Unless required by applicable law or agreed to in writing, software
+     distributed under the License is distributed on an "AS IS" BASIS,
+     WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+     See the License for the specific language governing permissions and
+     limitations under the License.
+ -->
+
+<resources xmlns:android="http://schemas.android.com/apk/res/android"
+    xmlns:xliff="urn:oasis:names:tc:xliff:document:1.2">
+    <string name="no_upstream_notification_title" msgid="611650570559011140">"ማስተሳሰር ምንም በይነመረብ የለውም"</string>
+    <string name="no_upstream_notification_message" msgid="6508394877641864863">"መሣሪያዎችን ማገናኘት አይቻልም"</string>
+    <string name="no_upstream_notification_disable_button" msgid="7609346639290990508">"ማስተሳሰርን አጥፋ"</string>
+    <string name="upstream_roaming_notification_title" msgid="6032901176124830787">"መገናኛ ነጥብ ወይም ማስተሳሰር በርቷል"</string>
+    <string name="upstream_roaming_notification_message" msgid="7599056263326217523">"በሚያንዣብብበት ጊዜ ተጨማሪ ክፍያዎች ተፈጻሚ ሊሆኑ ይችላሉ"</string>
+</resources>
diff --git a/Tethering/res/values-mcc311-mnc480-ar/strings.xml b/Tethering/res/values-mcc311-mnc480-ar/strings.xml
new file mode 100644
index 0000000..8467f9b
--- /dev/null
+++ b/Tethering/res/values-mcc311-mnc480-ar/strings.xml
@@ -0,0 +1,24 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!--  Copyright (C) 2020 The Android Open Source Project
+
+     Licensed under the Apache License, Version 2.0 (the "License");
+     you may not use this file except in compliance with the License.
+     You may obtain a copy of the License at
+
+          http://www.apache.org/licenses/LICENSE-2.0
+
+     Unless required by applicable law or agreed to in writing, software
+     distributed under the License is distributed on an "AS IS" BASIS,
+     WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+     See the License for the specific language governing permissions and
+     limitations under the License.
+ -->
+
+<resources xmlns:android="http://schemas.android.com/apk/res/android"
+    xmlns:xliff="urn:oasis:names:tc:xliff:document:1.2">
+    <string name="no_upstream_notification_title" msgid="611650570559011140">"ما مِن اتصال بالإنترنت خلال التوصيل"</string>
+    <string name="no_upstream_notification_message" msgid="6508394877641864863">"تعذّر اتصال الأجهزة"</string>
+    <string name="no_upstream_notification_disable_button" msgid="7609346639290990508">"إيقاف التوصيل"</string>
+    <string name="upstream_roaming_notification_title" msgid="6032901176124830787">"نقطة الاتصال أو التوصيل مفعّلان"</string>
+    <string name="upstream_roaming_notification_message" msgid="7599056263326217523">"قد يتم تطبيق رسوم إضافية أثناء التجوال."</string>
+</resources>
diff --git a/Tethering/res/values-mcc311-mnc480-as/strings.xml b/Tethering/res/values-mcc311-mnc480-as/strings.xml
new file mode 100644
index 0000000..9776bd8
--- /dev/null
+++ b/Tethering/res/values-mcc311-mnc480-as/strings.xml
@@ -0,0 +1,24 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!--  Copyright (C) 2020 The Android Open Source Project
+
+     Licensed under the Apache License, Version 2.0 (the "License");
+     you may not use this file except in compliance with the License.
+     You may obtain a copy of the License at
+
+          http://www.apache.org/licenses/LICENSE-2.0
+
+     Unless required by applicable law or agreed to in writing, software
+     distributed under the License is distributed on an "AS IS" BASIS,
+     WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+     See the License for the specific language governing permissions and
+     limitations under the License.
+ -->
+
+<resources xmlns:android="http://schemas.android.com/apk/res/android"
+    xmlns:xliff="urn:oasis:names:tc:xliff:document:1.2">
+    <string name="no_upstream_notification_title" msgid="611650570559011140">"টে\'ডাৰিঙৰ ইণ্টাৰনেট নাই"</string>
+    <string name="no_upstream_notification_message" msgid="6508394877641864863">"ডিভাইচসমূহ সংযোগ কৰিব নোৱাৰি"</string>
+    <string name="no_upstream_notification_disable_button" msgid="7609346639290990508">"টে\'ডাৰিং অফ কৰক"</string>
+    <string name="upstream_roaming_notification_title" msgid="6032901176124830787">"হটস্পট অথবা টে\'ডাৰিং অন আছে"</string>
+    <string name="upstream_roaming_notification_message" msgid="7599056263326217523">"ৰ\'মিঙত থাকিলে অতিৰিক্ত মাচুল প্ৰযোজ্য হ’ব পাৰে"</string>
+</resources>
diff --git a/Tethering/res/values-mcc311-mnc480-az/strings.xml b/Tethering/res/values-mcc311-mnc480-az/strings.xml
new file mode 100644
index 0000000..e6d3eaf
--- /dev/null
+++ b/Tethering/res/values-mcc311-mnc480-az/strings.xml
@@ -0,0 +1,24 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!--  Copyright (C) 2020 The Android Open Source Project
+
+     Licensed under the Apache License, Version 2.0 (the "License");
+     you may not use this file except in compliance with the License.
+     You may obtain a copy of the License at
+
+          http://www.apache.org/licenses/LICENSE-2.0
+
+     Unless required by applicable law or agreed to in writing, software
+     distributed under the License is distributed on an "AS IS" BASIS,
+     WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+     See the License for the specific language governing permissions and
+     limitations under the License.
+ -->
+
+<resources xmlns:android="http://schemas.android.com/apk/res/android"
+    xmlns:xliff="urn:oasis:names:tc:xliff:document:1.2">
+    <string name="no_upstream_notification_title" msgid="611650570559011140">"Modemin internetə girişi yoxdur"</string>
+    <string name="no_upstream_notification_message" msgid="6508394877641864863">"Cihazları qoşmaq mümkün deyil"</string>
+    <string name="no_upstream_notification_disable_button" msgid="7609346639290990508">"Modemi deaktiv edin"</string>
+    <string name="upstream_roaming_notification_title" msgid="6032901176124830787">"Hotspot və ya modem aktivdir"</string>
+    <string name="upstream_roaming_notification_message" msgid="7599056263326217523">"Rouminq zamanı əlavə ödənişlər tətbiq edilə bilər"</string>
+</resources>
diff --git a/Tethering/res/values-mcc311-mnc480-b+sr+Latn/strings.xml b/Tethering/res/values-mcc311-mnc480-b+sr+Latn/strings.xml
new file mode 100644
index 0000000..4c8a1df
--- /dev/null
+++ b/Tethering/res/values-mcc311-mnc480-b+sr+Latn/strings.xml
@@ -0,0 +1,24 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!--  Copyright (C) 2020 The Android Open Source Project
+
+     Licensed under the Apache License, Version 2.0 (the "License");
+     you may not use this file except in compliance with the License.
+     You may obtain a copy of the License at
+
+          http://www.apache.org/licenses/LICENSE-2.0
+
+     Unless required by applicable law or agreed to in writing, software
+     distributed under the License is distributed on an "AS IS" BASIS,
+     WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+     See the License for the specific language governing permissions and
+     limitations under the License.
+ -->
+
+<resources xmlns:android="http://schemas.android.com/apk/res/android"
+    xmlns:xliff="urn:oasis:names:tc:xliff:document:1.2">
+    <string name="no_upstream_notification_title" msgid="611650570559011140">"Privezivanje nema pristup internetu"</string>
+    <string name="no_upstream_notification_message" msgid="6508394877641864863">"Povezivanje uređaja nije uspelo"</string>
+    <string name="no_upstream_notification_disable_button" msgid="7609346639290990508">"Isključi privezivanje"</string>
+    <string name="upstream_roaming_notification_title" msgid="6032901176124830787">"Uključen je hotspot ili privezivanje"</string>
+    <string name="upstream_roaming_notification_message" msgid="7599056263326217523">"Možda važe dodatni troškovi u romingu"</string>
+</resources>
diff --git a/Tethering/res/values-mcc311-mnc480-be/strings.xml b/Tethering/res/values-mcc311-mnc480-be/strings.xml
new file mode 100644
index 0000000..edfa41e
--- /dev/null
+++ b/Tethering/res/values-mcc311-mnc480-be/strings.xml
@@ -0,0 +1,24 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!--  Copyright (C) 2020 The Android Open Source Project
+
+     Licensed under the Apache License, Version 2.0 (the "License");
+     you may not use this file except in compliance with the License.
+     You may obtain a copy of the License at
+
+          http://www.apache.org/licenses/LICENSE-2.0
+
+     Unless required by applicable law or agreed to in writing, software
+     distributed under the License is distributed on an "AS IS" BASIS,
+     WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+     See the License for the specific language governing permissions and
+     limitations under the License.
+ -->
+
+<resources xmlns:android="http://schemas.android.com/apk/res/android"
+    xmlns:xliff="urn:oasis:names:tc:xliff:document:1.2">
+    <string name="no_upstream_notification_title" msgid="611650570559011140">"Рэжым мадэма выкарыстоўваецца без доступу да інтэрнэту"</string>
+    <string name="no_upstream_notification_message" msgid="6508394877641864863">"Не ўдалося падключыць прылады"</string>
+    <string name="no_upstream_notification_disable_button" msgid="7609346639290990508">"Выключыць рэжым мадэма"</string>
+    <string name="upstream_roaming_notification_title" msgid="6032901176124830787">"Хот-спот або рэжым мадэма ўключаны"</string>
+    <string name="upstream_roaming_notification_message" msgid="7599056263326217523">"Пры выкарыстанні роўмінгу можа спаганяцца дадатковая плата"</string>
+</resources>
diff --git a/Tethering/res/values-mcc311-mnc480-bg/strings.xml b/Tethering/res/values-mcc311-mnc480-bg/strings.xml
new file mode 100644
index 0000000..f563981
--- /dev/null
+++ b/Tethering/res/values-mcc311-mnc480-bg/strings.xml
@@ -0,0 +1,24 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!--  Copyright (C) 2020 The Android Open Source Project
+
+     Licensed under the Apache License, Version 2.0 (the "License");
+     you may not use this file except in compliance with the License.
+     You may obtain a copy of the License at
+
+          http://www.apache.org/licenses/LICENSE-2.0
+
+     Unless required by applicable law or agreed to in writing, software
+     distributed under the License is distributed on an "AS IS" BASIS,
+     WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+     See the License for the specific language governing permissions and
+     limitations under the License.
+ -->
+
+<resources xmlns:android="http://schemas.android.com/apk/res/android"
+    xmlns:xliff="urn:oasis:names:tc:xliff:document:1.2">
+    <string name="no_upstream_notification_title" msgid="611650570559011140">"Тетърингът няма връзка с интернет"</string>
+    <string name="no_upstream_notification_message" msgid="6508394877641864863">"Устройствата не могат да установят връзка"</string>
+    <string name="no_upstream_notification_disable_button" msgid="7609346639290990508">"Изключване на тетъринга"</string>
+    <string name="upstream_roaming_notification_title" msgid="6032901176124830787">"Точката за достъп или тетърингът са включени"</string>
+    <string name="upstream_roaming_notification_message" msgid="7599056263326217523">"Възможно е да ви бъдат начислени допълнителни такси при роуминг"</string>
+</resources>
diff --git a/Tethering/res/values-mcc311-mnc480-bn/strings.xml b/Tethering/res/values-mcc311-mnc480-bn/strings.xml
new file mode 100644
index 0000000..d8ecd2e
--- /dev/null
+++ b/Tethering/res/values-mcc311-mnc480-bn/strings.xml
@@ -0,0 +1,24 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!--  Copyright (C) 2020 The Android Open Source Project
+
+     Licensed under the Apache License, Version 2.0 (the "License");
+     you may not use this file except in compliance with the License.
+     You may obtain a copy of the License at
+
+          http://www.apache.org/licenses/LICENSE-2.0
+
+     Unless required by applicable law or agreed to in writing, software
+     distributed under the License is distributed on an "AS IS" BASIS,
+     WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+     See the License for the specific language governing permissions and
+     limitations under the License.
+ -->
+
+<resources xmlns:android="http://schemas.android.com/apk/res/android"
+    xmlns:xliff="urn:oasis:names:tc:xliff:document:1.2">
+    <string name="no_upstream_notification_title" msgid="611650570559011140">"টিথারিং করার জন্য কোনও ইন্টারনেট কানেকশন নেই"</string>
+    <string name="no_upstream_notification_message" msgid="6508394877641864863">"ডিভাইস কানেক্ট করতে পারছে না"</string>
+    <string name="no_upstream_notification_disable_button" msgid="7609346639290990508">"টিথারিং বন্ধ করুন"</string>
+    <string name="upstream_roaming_notification_title" msgid="6032901176124830787">"হটস্পট বা টিথারিং চালু আছে"</string>
+    <string name="upstream_roaming_notification_message" msgid="7599056263326217523">"রোমিংয়ের সময় অতিরিক্ত চার্জ করা হতে পারে"</string>
+</resources>
diff --git a/Tethering/res/values-mcc311-mnc480-bs/strings.xml b/Tethering/res/values-mcc311-mnc480-bs/strings.xml
new file mode 100644
index 0000000..b85fd5e
--- /dev/null
+++ b/Tethering/res/values-mcc311-mnc480-bs/strings.xml
@@ -0,0 +1,24 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!--  Copyright (C) 2020 The Android Open Source Project
+
+     Licensed under the Apache License, Version 2.0 (the "License");
+     you may not use this file except in compliance with the License.
+     You may obtain a copy of the License at
+
+          http://www.apache.org/licenses/LICENSE-2.0
+
+     Unless required by applicable law or agreed to in writing, software
+     distributed under the License is distributed on an "AS IS" BASIS,
+     WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+     See the License for the specific language governing permissions and
+     limitations under the License.
+ -->
+
+<resources xmlns:android="http://schemas.android.com/apk/res/android"
+    xmlns:xliff="urn:oasis:names:tc:xliff:document:1.2">
+    <string name="no_upstream_notification_title" msgid="611650570559011140">"Povezivanje putem mobitela nema internet"</string>
+    <string name="no_upstream_notification_message" msgid="6508394877641864863">"Uređaji se ne mogu povezati"</string>
+    <string name="no_upstream_notification_disable_button" msgid="7609346639290990508">"Isključi povezivanje putem mobitela"</string>
+    <string name="upstream_roaming_notification_title" msgid="6032901176124830787">"Pristupna tačka ili povezivanje putem mobitela je uključeno"</string>
+    <string name="upstream_roaming_notification_message" msgid="7599056263326217523">"Mogu nastati dodatni troškovi u romingu"</string>
+</resources>
diff --git a/Tethering/res/values-mcc311-mnc480-ca/strings.xml b/Tethering/res/values-mcc311-mnc480-ca/strings.xml
new file mode 100644
index 0000000..a357215
--- /dev/null
+++ b/Tethering/res/values-mcc311-mnc480-ca/strings.xml
@@ -0,0 +1,24 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!--  Copyright (C) 2020 The Android Open Source Project
+
+     Licensed under the Apache License, Version 2.0 (the "License");
+     you may not use this file except in compliance with the License.
+     You may obtain a copy of the License at
+
+          http://www.apache.org/licenses/LICENSE-2.0
+
+     Unless required by applicable law or agreed to in writing, software
+     distributed under the License is distributed on an "AS IS" BASIS,
+     WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+     See the License for the specific language governing permissions and
+     limitations under the License.
+ -->
+
+<resources xmlns:android="http://schemas.android.com/apk/res/android"
+    xmlns:xliff="urn:oasis:names:tc:xliff:document:1.2">
+    <string name="no_upstream_notification_title" msgid="611650570559011140">"La compartició de xarxa no té accés a Internet"</string>
+    <string name="no_upstream_notification_message" msgid="6508394877641864863">"No es poden connectar els dispositius"</string>
+    <string name="no_upstream_notification_disable_button" msgid="7609346639290990508">"Desactiva la compartició de xarxa"</string>
+    <string name="upstream_roaming_notification_title" msgid="6032901176124830787">"S\'ha activat el punt d\'accés Wi‑Fi o la compartició de xarxa"</string>
+    <string name="upstream_roaming_notification_message" msgid="7599056263326217523">"És possible que s\'apliquin costos addicionals en itinerància"</string>
+</resources>
diff --git a/Tethering/res/values-mcc311-mnc480-cs/strings.xml b/Tethering/res/values-mcc311-mnc480-cs/strings.xml
new file mode 100644
index 0000000..91196be
--- /dev/null
+++ b/Tethering/res/values-mcc311-mnc480-cs/strings.xml
@@ -0,0 +1,24 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!--  Copyright (C) 2020 The Android Open Source Project
+
+     Licensed under the Apache License, Version 2.0 (the "License");
+     you may not use this file except in compliance with the License.
+     You may obtain a copy of the License at
+
+          http://www.apache.org/licenses/LICENSE-2.0
+
+     Unless required by applicable law or agreed to in writing, software
+     distributed under the License is distributed on an "AS IS" BASIS,
+     WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+     See the License for the specific language governing permissions and
+     limitations under the License.
+ -->
+
+<resources xmlns:android="http://schemas.android.com/apk/res/android"
+    xmlns:xliff="urn:oasis:names:tc:xliff:document:1.2">
+    <string name="no_upstream_notification_title" msgid="611650570559011140">"Tethering nemá připojení k internetu"</string>
+    <string name="no_upstream_notification_message" msgid="6508394877641864863">"Zařízení se nemůžou připojit"</string>
+    <string name="no_upstream_notification_disable_button" msgid="7609346639290990508">"Vypnout tethering"</string>
+    <string name="upstream_roaming_notification_title" msgid="6032901176124830787">"Je zapnutý hotspot nebo tethering"</string>
+    <string name="upstream_roaming_notification_message" msgid="7599056263326217523">"Při roamingu mohou být účtovány dodatečné poplatky"</string>
+</resources>
diff --git a/Tethering/res/values-mcc311-mnc480-da/strings.xml b/Tethering/res/values-mcc311-mnc480-da/strings.xml
new file mode 100644
index 0000000..1968900
--- /dev/null
+++ b/Tethering/res/values-mcc311-mnc480-da/strings.xml
@@ -0,0 +1,24 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!--  Copyright (C) 2020 The Android Open Source Project
+
+     Licensed under the Apache License, Version 2.0 (the "License");
+     you may not use this file except in compliance with the License.
+     You may obtain a copy of the License at
+
+          http://www.apache.org/licenses/LICENSE-2.0
+
+     Unless required by applicable law or agreed to in writing, software
+     distributed under the License is distributed on an "AS IS" BASIS,
+     WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+     See the License for the specific language governing permissions and
+     limitations under the License.
+ -->
+
+<resources xmlns:android="http://schemas.android.com/apk/res/android"
+    xmlns:xliff="urn:oasis:names:tc:xliff:document:1.2">
+    <string name="no_upstream_notification_title" msgid="611650570559011140">"Netdeling har ingen internetforbindelse"</string>
+    <string name="no_upstream_notification_message" msgid="6508394877641864863">"Enheder kan ikke oprette forbindelse"</string>
+    <string name="no_upstream_notification_disable_button" msgid="7609346639290990508">"Deaktiver netdeling"</string>
+    <string name="upstream_roaming_notification_title" msgid="6032901176124830787">"Hotspot eller netdeling er aktiveret"</string>
+    <string name="upstream_roaming_notification_message" msgid="7599056263326217523">"Der opkræves muligvis yderligere gebyrer ved roaming"</string>
+</resources>
diff --git a/Tethering/res/values-mcc311-mnc480-de/strings.xml b/Tethering/res/values-mcc311-mnc480-de/strings.xml
new file mode 100644
index 0000000..eb3f8c5
--- /dev/null
+++ b/Tethering/res/values-mcc311-mnc480-de/strings.xml
@@ -0,0 +1,24 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!--  Copyright (C) 2020 The Android Open Source Project
+
+     Licensed under the Apache License, Version 2.0 (the "License");
+     you may not use this file except in compliance with the License.
+     You may obtain a copy of the License at
+
+          http://www.apache.org/licenses/LICENSE-2.0
+
+     Unless required by applicable law or agreed to in writing, software
+     distributed under the License is distributed on an "AS IS" BASIS,
+     WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+     See the License for the specific language governing permissions and
+     limitations under the License.
+ -->
+
+<resources xmlns:android="http://schemas.android.com/apk/res/android"
+    xmlns:xliff="urn:oasis:names:tc:xliff:document:1.2">
+    <string name="no_upstream_notification_title" msgid="611650570559011140">"Tethering hat keinen Internetzugriff"</string>
+    <string name="no_upstream_notification_message" msgid="6508394877641864863">"Geräte können sich nicht verbinden"</string>
+    <string name="no_upstream_notification_disable_button" msgid="7609346639290990508">"Tethering deaktivieren"</string>
+    <string name="upstream_roaming_notification_title" msgid="6032901176124830787">"Hotspot oder Tethering ist aktiviert"</string>
+    <string name="upstream_roaming_notification_message" msgid="7599056263326217523">"Für das Roaming können zusätzliche Gebühren anfallen"</string>
+</resources>
diff --git a/Tethering/res/values-mcc311-mnc480-el/strings.xml b/Tethering/res/values-mcc311-mnc480-el/strings.xml
new file mode 100644
index 0000000..56c3d81
--- /dev/null
+++ b/Tethering/res/values-mcc311-mnc480-el/strings.xml
@@ -0,0 +1,24 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!--  Copyright (C) 2020 The Android Open Source Project
+
+     Licensed under the Apache License, Version 2.0 (the "License");
+     you may not use this file except in compliance with the License.
+     You may obtain a copy of the License at
+
+          http://www.apache.org/licenses/LICENSE-2.0
+
+     Unless required by applicable law or agreed to in writing, software
+     distributed under the License is distributed on an "AS IS" BASIS,
+     WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+     See the License for the specific language governing permissions and
+     limitations under the License.
+ -->
+
+<resources xmlns:android="http://schemas.android.com/apk/res/android"
+    xmlns:xliff="urn:oasis:names:tc:xliff:document:1.2">
+    <string name="no_upstream_notification_title" msgid="611650570559011140">"Η σύνδεση δεν έχει πρόσβαση στο διαδίκτυο"</string>
+    <string name="no_upstream_notification_message" msgid="6508394877641864863">"Δεν είναι δυνατή η σύνδεση των συσκευών"</string>
+    <string name="no_upstream_notification_disable_button" msgid="7609346639290990508">"Απενεργοποιήστε τη σύνδεση"</string>
+    <string name="upstream_roaming_notification_title" msgid="6032901176124830787">"Ενεργό σημείο πρόσβασης Wi-Fi ή ενεργή σύνδεση"</string>
+    <string name="upstream_roaming_notification_message" msgid="7599056263326217523">"Ενδέχεται να ισχύουν επιπλέον χρεώσεις κατά την περιαγωγή."</string>
+</resources>
diff --git a/Tethering/res/values-mcc311-mnc480-en-rAU/strings.xml b/Tethering/res/values-mcc311-mnc480-en-rAU/strings.xml
new file mode 100644
index 0000000..dd1a197
--- /dev/null
+++ b/Tethering/res/values-mcc311-mnc480-en-rAU/strings.xml
@@ -0,0 +1,24 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!--  Copyright (C) 2020 The Android Open Source Project
+
+     Licensed under the Apache License, Version 2.0 (the "License");
+     you may not use this file except in compliance with the License.
+     You may obtain a copy of the License at
+
+          http://www.apache.org/licenses/LICENSE-2.0
+
+     Unless required by applicable law or agreed to in writing, software
+     distributed under the License is distributed on an "AS IS" BASIS,
+     WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+     See the License for the specific language governing permissions and
+     limitations under the License.
+ -->
+
+<resources xmlns:android="http://schemas.android.com/apk/res/android"
+    xmlns:xliff="urn:oasis:names:tc:xliff:document:1.2">
+    <string name="no_upstream_notification_title" msgid="611650570559011140">"Tethering has no Internet"</string>
+    <string name="no_upstream_notification_message" msgid="6508394877641864863">"Devices can’t connect"</string>
+    <string name="no_upstream_notification_disable_button" msgid="7609346639290990508">"Turn off tethering"</string>
+    <string name="upstream_roaming_notification_title" msgid="6032901176124830787">"Hotspot or tethering is on"</string>
+    <string name="upstream_roaming_notification_message" msgid="7599056263326217523">"Additional charges may apply while roaming"</string>
+</resources>
diff --git a/Tethering/res/values-mcc311-mnc480-en-rCA/strings.xml b/Tethering/res/values-mcc311-mnc480-en-rCA/strings.xml
new file mode 100644
index 0000000..dd1a197
--- /dev/null
+++ b/Tethering/res/values-mcc311-mnc480-en-rCA/strings.xml
@@ -0,0 +1,24 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!--  Copyright (C) 2020 The Android Open Source Project
+
+     Licensed under the Apache License, Version 2.0 (the "License");
+     you may not use this file except in compliance with the License.
+     You may obtain a copy of the License at
+
+          http://www.apache.org/licenses/LICENSE-2.0
+
+     Unless required by applicable law or agreed to in writing, software
+     distributed under the License is distributed on an "AS IS" BASIS,
+     WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+     See the License for the specific language governing permissions and
+     limitations under the License.
+ -->
+
+<resources xmlns:android="http://schemas.android.com/apk/res/android"
+    xmlns:xliff="urn:oasis:names:tc:xliff:document:1.2">
+    <string name="no_upstream_notification_title" msgid="611650570559011140">"Tethering has no Internet"</string>
+    <string name="no_upstream_notification_message" msgid="6508394877641864863">"Devices can’t connect"</string>
+    <string name="no_upstream_notification_disable_button" msgid="7609346639290990508">"Turn off tethering"</string>
+    <string name="upstream_roaming_notification_title" msgid="6032901176124830787">"Hotspot or tethering is on"</string>
+    <string name="upstream_roaming_notification_message" msgid="7599056263326217523">"Additional charges may apply while roaming"</string>
+</resources>
diff --git a/Tethering/res/values-mcc311-mnc480-en-rGB/strings.xml b/Tethering/res/values-mcc311-mnc480-en-rGB/strings.xml
new file mode 100644
index 0000000..dd1a197
--- /dev/null
+++ b/Tethering/res/values-mcc311-mnc480-en-rGB/strings.xml
@@ -0,0 +1,24 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!--  Copyright (C) 2020 The Android Open Source Project
+
+     Licensed under the Apache License, Version 2.0 (the "License");
+     you may not use this file except in compliance with the License.
+     You may obtain a copy of the License at
+
+          http://www.apache.org/licenses/LICENSE-2.0
+
+     Unless required by applicable law or agreed to in writing, software
+     distributed under the License is distributed on an "AS IS" BASIS,
+     WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+     See the License for the specific language governing permissions and
+     limitations under the License.
+ -->
+
+<resources xmlns:android="http://schemas.android.com/apk/res/android"
+    xmlns:xliff="urn:oasis:names:tc:xliff:document:1.2">
+    <string name="no_upstream_notification_title" msgid="611650570559011140">"Tethering has no Internet"</string>
+    <string name="no_upstream_notification_message" msgid="6508394877641864863">"Devices can’t connect"</string>
+    <string name="no_upstream_notification_disable_button" msgid="7609346639290990508">"Turn off tethering"</string>
+    <string name="upstream_roaming_notification_title" msgid="6032901176124830787">"Hotspot or tethering is on"</string>
+    <string name="upstream_roaming_notification_message" msgid="7599056263326217523">"Additional charges may apply while roaming"</string>
+</resources>
diff --git a/Tethering/res/values-mcc311-mnc480-en-rIN/strings.xml b/Tethering/res/values-mcc311-mnc480-en-rIN/strings.xml
new file mode 100644
index 0000000..dd1a197
--- /dev/null
+++ b/Tethering/res/values-mcc311-mnc480-en-rIN/strings.xml
@@ -0,0 +1,24 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!--  Copyright (C) 2020 The Android Open Source Project
+
+     Licensed under the Apache License, Version 2.0 (the "License");
+     you may not use this file except in compliance with the License.
+     You may obtain a copy of the License at
+
+          http://www.apache.org/licenses/LICENSE-2.0
+
+     Unless required by applicable law or agreed to in writing, software
+     distributed under the License is distributed on an "AS IS" BASIS,
+     WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+     See the License for the specific language governing permissions and
+     limitations under the License.
+ -->
+
+<resources xmlns:android="http://schemas.android.com/apk/res/android"
+    xmlns:xliff="urn:oasis:names:tc:xliff:document:1.2">
+    <string name="no_upstream_notification_title" msgid="611650570559011140">"Tethering has no Internet"</string>
+    <string name="no_upstream_notification_message" msgid="6508394877641864863">"Devices can’t connect"</string>
+    <string name="no_upstream_notification_disable_button" msgid="7609346639290990508">"Turn off tethering"</string>
+    <string name="upstream_roaming_notification_title" msgid="6032901176124830787">"Hotspot or tethering is on"</string>
+    <string name="upstream_roaming_notification_message" msgid="7599056263326217523">"Additional charges may apply while roaming"</string>
+</resources>
diff --git a/Tethering/res/values-mcc311-mnc480-en-rXC/strings.xml b/Tethering/res/values-mcc311-mnc480-en-rXC/strings.xml
new file mode 100644
index 0000000..d3347aa
--- /dev/null
+++ b/Tethering/res/values-mcc311-mnc480-en-rXC/strings.xml
@@ -0,0 +1,24 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!--  Copyright (C) 2020 The Android Open Source Project
+
+     Licensed under the Apache License, Version 2.0 (the "License");
+     you may not use this file except in compliance with the License.
+     You may obtain a copy of the License at
+
+          http://www.apache.org/licenses/LICENSE-2.0
+
+     Unless required by applicable law or agreed to in writing, software
+     distributed under the License is distributed on an "AS IS" BASIS,
+     WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+     See the License for the specific language governing permissions and
+     limitations under the License.
+ -->
+
+<resources xmlns:android="http://schemas.android.com/apk/res/android"
+    xmlns:xliff="urn:oasis:names:tc:xliff:document:1.2">
+    <string name="no_upstream_notification_title" msgid="611650570559011140">"‎‏‎‎‎‎‎‏‎‏‏‏‎‎‎‎‎‎‏‎‎‏‎‎‎‎‏‏‏‏‏‎‎‏‎‎‎‎‏‏‏‏‏‎‏‎‎‎‎‎‏‎‎‏‏‏‏‎‏‎‎‎‎‎‎‏‎‎‎‏‏‎‏‎‏‎‏‏‎‏‏‏‎‎‏‎‏‎‎‎‏‎‎‎Tethering has no internet‎‏‎‎‏‎"</string>
+    <string name="no_upstream_notification_message" msgid="6508394877641864863">"‎‏‎‎‎‎‎‏‎‏‏‏‎‎‎‎‎‎‏‎‎‏‎‎‎‎‏‏‏‏‏‏‏‏‎‏‏‎‏‎‎‏‎‏‎‎‏‎‎‏‏‏‎‏‏‎‏‎‏‎‏‎‎‎‏‎‎‎‎‎‏‏‏‏‎‏‎‎‎‎‏‎‏‏‎‏‏‎‏‎‎‏‏‏‏‏‎Devices can’t connect‎‏‎‎‏‎"</string>
+    <string name="no_upstream_notification_disable_button" msgid="7609346639290990508">"‎‏‎‎‎‎‎‏‎‏‏‏‎‎‎‎‎‎‏‎‎‏‎‎‎‎‏‏‏‏‏‏‏‏‏‎‏‎‎‏‏‎‎‏‏‎‎‏‏‏‎‏‎‏‎‎‎‏‏‏‎‎‏‏‏‏‎‎‏‏‏‏‏‏‎‎‎‎‎‎‎‏‏‏‏‏‏‏‏‎‏‎‏‏‎‎‎Turn off tethering‎‏‎‎‏‎"</string>
+    <string name="upstream_roaming_notification_title" msgid="6032901176124830787">"‎‏‎‎‎‎‎‏‎‏‏‏‎‎‎‎‎‎‏‎‎‏‎‎‎‎‏‏‏‏‏‏‏‏‎‏‎‎‏‏‏‎‏‏‏‎‎‏‎‎‏‎‏‎‏‏‏‎‏‎‎‏‏‏‏‏‏‎‏‏‏‏‏‏‏‏‎‏‎‎‏‏‏‏‎‏‎‎‎‏‎‎‎‎‏‏‎Hotspot or tethering is on‎‏‎‎‏‎"</string>
+    <string name="upstream_roaming_notification_message" msgid="7599056263326217523">"‎‏‎‎‎‎‎‏‎‏‏‏‎‎‎‎‎‎‏‎‎‏‎‎‎‎‏‏‏‏‏‏‏‏‏‎‏‎‎‏‎‏‏‏‎‏‎‏‎‏‎‎‎‏‎‏‎‏‏‎‏‎‎‎‏‏‏‏‎‎‏‏‏‏‎‎‎‏‎‎‎‎‏‏‎‏‎‏‎‎‏‏‎‎‏‏‎Additional charges may apply while roaming‎‏‎‎‏‎"</string>
+</resources>
diff --git a/Tethering/res/values-mcc311-mnc480-es-rUS/strings.xml b/Tethering/res/values-mcc311-mnc480-es-rUS/strings.xml
new file mode 100644
index 0000000..2f0504f
--- /dev/null
+++ b/Tethering/res/values-mcc311-mnc480-es-rUS/strings.xml
@@ -0,0 +1,24 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!--  Copyright (C) 2020 The Android Open Source Project
+
+     Licensed under the Apache License, Version 2.0 (the "License");
+     you may not use this file except in compliance with the License.
+     You may obtain a copy of the License at
+
+          http://www.apache.org/licenses/LICENSE-2.0
+
+     Unless required by applicable law or agreed to in writing, software
+     distributed under the License is distributed on an "AS IS" BASIS,
+     WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+     See the License for the specific language governing permissions and
+     limitations under the License.
+ -->
+
+<resources xmlns:android="http://schemas.android.com/apk/res/android"
+    xmlns:xliff="urn:oasis:names:tc:xliff:document:1.2">
+    <string name="no_upstream_notification_title" msgid="611650570559011140">"La conexión mediante dispositivo móvil no tiene Internet"</string>
+    <string name="no_upstream_notification_message" msgid="6508394877641864863">"No se pueden conectar los dispositivos"</string>
+    <string name="no_upstream_notification_disable_button" msgid="7609346639290990508">"Desactivar conexión mediante dispositivo móvil"</string>
+    <string name="upstream_roaming_notification_title" msgid="6032901176124830787">"Se activó el hotspot o la conexión mediante dispositivo móvil"</string>
+    <string name="upstream_roaming_notification_message" msgid="7599056263326217523">"Es posible que se apliquen cargos adicionales por roaming"</string>
+</resources>
diff --git a/Tethering/res/values-mcc311-mnc480-es/strings.xml b/Tethering/res/values-mcc311-mnc480-es/strings.xml
new file mode 100644
index 0000000..2d8f882
--- /dev/null
+++ b/Tethering/res/values-mcc311-mnc480-es/strings.xml
@@ -0,0 +1,24 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!--  Copyright (C) 2020 The Android Open Source Project
+
+     Licensed under the Apache License, Version 2.0 (the "License");
+     you may not use this file except in compliance with the License.
+     You may obtain a copy of the License at
+
+          http://www.apache.org/licenses/LICENSE-2.0
+
+     Unless required by applicable law or agreed to in writing, software
+     distributed under the License is distributed on an "AS IS" BASIS,
+     WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+     See the License for the specific language governing permissions and
+     limitations under the License.
+ -->
+
+<resources xmlns:android="http://schemas.android.com/apk/res/android"
+    xmlns:xliff="urn:oasis:names:tc:xliff:document:1.2">
+    <string name="no_upstream_notification_title" msgid="611650570559011140">"La conexión no se puede compartir, porque no hay acceso a Internet"</string>
+    <string name="no_upstream_notification_message" msgid="6508394877641864863">"Los dispositivos no se pueden conectar"</string>
+    <string name="no_upstream_notification_disable_button" msgid="7609346639290990508">"Desactivar conexión compartida"</string>
+    <string name="upstream_roaming_notification_title" msgid="6032901176124830787">"Punto de acceso o conexión compartida activados"</string>
+    <string name="upstream_roaming_notification_message" msgid="7599056263326217523">"Puede que se apliquen cargos adicionales en itinerancia"</string>
+</resources>
diff --git a/Tethering/res/values-mcc311-mnc480-et/strings.xml b/Tethering/res/values-mcc311-mnc480-et/strings.xml
new file mode 100644
index 0000000..8493c47
--- /dev/null
+++ b/Tethering/res/values-mcc311-mnc480-et/strings.xml
@@ -0,0 +1,24 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!--  Copyright (C) 2020 The Android Open Source Project
+
+     Licensed under the Apache License, Version 2.0 (the "License");
+     you may not use this file except in compliance with the License.
+     You may obtain a copy of the License at
+
+          http://www.apache.org/licenses/LICENSE-2.0
+
+     Unless required by applicable law or agreed to in writing, software
+     distributed under the License is distributed on an "AS IS" BASIS,
+     WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+     See the License for the specific language governing permissions and
+     limitations under the License.
+ -->
+
+<resources xmlns:android="http://schemas.android.com/apk/res/android"
+    xmlns:xliff="urn:oasis:names:tc:xliff:document:1.2">
+    <string name="no_upstream_notification_title" msgid="611650570559011140">"Jagamisel puudub internetiühendus"</string>
+    <string name="no_upstream_notification_message" msgid="6508394877641864863">"Seadmed ei saa ühendust luua"</string>
+    <string name="no_upstream_notification_disable_button" msgid="7609346639290990508">"Lülita jagamine välja"</string>
+    <string name="upstream_roaming_notification_title" msgid="6032901176124830787">"Kuumkoht või jagamine on sisse lülitatud"</string>
+    <string name="upstream_roaming_notification_message" msgid="7599056263326217523">"Rändluse kasutamisega võivad kaasneda lisatasud"</string>
+</resources>
diff --git a/Tethering/res/values-mcc311-mnc480-eu/strings.xml b/Tethering/res/values-mcc311-mnc480-eu/strings.xml
new file mode 100644
index 0000000..33bccab
--- /dev/null
+++ b/Tethering/res/values-mcc311-mnc480-eu/strings.xml
@@ -0,0 +1,24 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!--  Copyright (C) 2020 The Android Open Source Project
+
+     Licensed under the Apache License, Version 2.0 (the "License");
+     you may not use this file except in compliance with the License.
+     You may obtain a copy of the License at
+
+          http://www.apache.org/licenses/LICENSE-2.0
+
+     Unless required by applicable law or agreed to in writing, software
+     distributed under the License is distributed on an "AS IS" BASIS,
+     WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+     See the License for the specific language governing permissions and
+     limitations under the License.
+ -->
+
+<resources xmlns:android="http://schemas.android.com/apk/res/android"
+    xmlns:xliff="urn:oasis:names:tc:xliff:document:1.2">
+    <string name="no_upstream_notification_title" msgid="611650570559011140">"Konexioa partekatzeko aukerak ez du Interneteko konexiorik"</string>
+    <string name="no_upstream_notification_message" msgid="6508394877641864863">"Ezin dira konektatu gailuak"</string>
+    <string name="no_upstream_notification_disable_button" msgid="7609346639290990508">"Desaktibatu konexioa partekatzeko aukera"</string>
+    <string name="upstream_roaming_notification_title" msgid="6032901176124830787">"Wifi-gunea edo konexioa partekatzeko aukera aktibatuta dago"</string>
+    <string name="upstream_roaming_notification_message" msgid="7599056263326217523">"Baliteke kostu gehigarriak ordaindu behar izatea ibiltaritzan"</string>
+</resources>
diff --git a/Tethering/res/values-mcc311-mnc480-fa/strings.xml b/Tethering/res/values-mcc311-mnc480-fa/strings.xml
new file mode 100644
index 0000000..cf8a0cc
--- /dev/null
+++ b/Tethering/res/values-mcc311-mnc480-fa/strings.xml
@@ -0,0 +1,24 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!--  Copyright (C) 2020 The Android Open Source Project
+
+     Licensed under the Apache License, Version 2.0 (the "License");
+     you may not use this file except in compliance with the License.
+     You may obtain a copy of the License at
+
+          http://www.apache.org/licenses/LICENSE-2.0
+
+     Unless required by applicable law or agreed to in writing, software
+     distributed under the License is distributed on an "AS IS" BASIS,
+     WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+     See the License for the specific language governing permissions and
+     limitations under the License.
+ -->
+
+<resources xmlns:android="http://schemas.android.com/apk/res/android"
+    xmlns:xliff="urn:oasis:names:tc:xliff:document:1.2">
+    <string name="no_upstream_notification_title" msgid="611650570559011140">"«اشتراک‌گذاری اینترنت» به اینترنت دسترسی ندارد"</string>
+    <string name="no_upstream_notification_message" msgid="6508394877641864863">"دستگاه‌ها متصل نمی‌شوند"</string>
+    <string name="no_upstream_notification_disable_button" msgid="7609346639290990508">"خاموش کردن «اشتراک‌گذاری اینترنت»"</string>
+    <string name="upstream_roaming_notification_title" msgid="6032901176124830787">"«نقطه اتصال» یا «اشتراک‌گذاری اینترنت» روشن است"</string>
+    <string name="upstream_roaming_notification_message" msgid="7599056263326217523">"ممکن است درحین فراگردی تغییرات دیگر اعمال شود"</string>
+</resources>
diff --git a/Tethering/res/values-mcc311-mnc480-fi/strings.xml b/Tethering/res/values-mcc311-mnc480-fi/strings.xml
new file mode 100644
index 0000000..6a3ab80
--- /dev/null
+++ b/Tethering/res/values-mcc311-mnc480-fi/strings.xml
@@ -0,0 +1,24 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!--  Copyright (C) 2020 The Android Open Source Project
+
+     Licensed under the Apache License, Version 2.0 (the "License");
+     you may not use this file except in compliance with the License.
+     You may obtain a copy of the License at
+
+          http://www.apache.org/licenses/LICENSE-2.0
+
+     Unless required by applicable law or agreed to in writing, software
+     distributed under the License is distributed on an "AS IS" BASIS,
+     WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+     See the License for the specific language governing permissions and
+     limitations under the License.
+ -->
+
+<resources xmlns:android="http://schemas.android.com/apk/res/android"
+    xmlns:xliff="urn:oasis:names:tc:xliff:document:1.2">
+    <string name="no_upstream_notification_title" msgid="611650570559011140">"Ei jaettavaa internetyhteyttä"</string>
+    <string name="no_upstream_notification_message" msgid="6508394877641864863">"Laitteet eivät voi muodostaa yhteyttä"</string>
+    <string name="no_upstream_notification_disable_button" msgid="7609346639290990508">"Laita yhteyden jakaminen pois päältä"</string>
+    <string name="upstream_roaming_notification_title" msgid="6032901176124830787">"Hotspot tai yhteyden jakaminen on päällä"</string>
+    <string name="upstream_roaming_notification_message" msgid="7599056263326217523">"Roaming voi aiheuttaa lisämaksuja"</string>
+</resources>
diff --git a/Tethering/res/values-mcc311-mnc480-fr-rCA/strings.xml b/Tethering/res/values-mcc311-mnc480-fr-rCA/strings.xml
new file mode 100644
index 0000000..ffb9bf6
--- /dev/null
+++ b/Tethering/res/values-mcc311-mnc480-fr-rCA/strings.xml
@@ -0,0 +1,24 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!--  Copyright (C) 2020 The Android Open Source Project
+
+     Licensed under the Apache License, Version 2.0 (the "License");
+     you may not use this file except in compliance with the License.
+     You may obtain a copy of the License at
+
+          http://www.apache.org/licenses/LICENSE-2.0
+
+     Unless required by applicable law or agreed to in writing, software
+     distributed under the License is distributed on an "AS IS" BASIS,
+     WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+     See the License for the specific language governing permissions and
+     limitations under the License.
+ -->
+
+<resources xmlns:android="http://schemas.android.com/apk/res/android"
+    xmlns:xliff="urn:oasis:names:tc:xliff:document:1.2">
+    <string name="no_upstream_notification_title" msgid="611650570559011140">"Le partage de connexion n\'est pas connecté à Internet"</string>
+    <string name="no_upstream_notification_message" msgid="6508394877641864863">"Impossible de connecter les appareils"</string>
+    <string name="no_upstream_notification_disable_button" msgid="7609346639290990508">"Désactiver le partage de connexion"</string>
+    <string name="upstream_roaming_notification_title" msgid="6032901176124830787">"Le point d\'accès ou le partage de connexion est activé"</string>
+    <string name="upstream_roaming_notification_message" msgid="7599056263326217523">"En itinérance, des frais supplémentaires peuvent s\'appliquer"</string>
+</resources>
diff --git a/Tethering/res/values-mcc311-mnc480-fr/strings.xml b/Tethering/res/values-mcc311-mnc480-fr/strings.xml
new file mode 100644
index 0000000..768bce3
--- /dev/null
+++ b/Tethering/res/values-mcc311-mnc480-fr/strings.xml
@@ -0,0 +1,24 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!--  Copyright (C) 2020 The Android Open Source Project
+
+     Licensed under the Apache License, Version 2.0 (the "License");
+     you may not use this file except in compliance with the License.
+     You may obtain a copy of the License at
+
+          http://www.apache.org/licenses/LICENSE-2.0
+
+     Unless required by applicable law or agreed to in writing, software
+     distributed under the License is distributed on an "AS IS" BASIS,
+     WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+     See the License for the specific language governing permissions and
+     limitations under the License.
+ -->
+
+<resources xmlns:android="http://schemas.android.com/apk/res/android"
+    xmlns:xliff="urn:oasis:names:tc:xliff:document:1.2">
+    <string name="no_upstream_notification_title" msgid="611650570559011140">"Aucune connexion à Internet n\'est disponible pour le partage de connexion"</string>
+    <string name="no_upstream_notification_message" msgid="6508394877641864863">"Impossible de connecter les appareils"</string>
+    <string name="no_upstream_notification_disable_button" msgid="7609346639290990508">"Désactiver le partage de connexion"</string>
+    <string name="upstream_roaming_notification_title" msgid="6032901176124830787">"Le point d\'accès ou le partage de connexion est activé"</string>
+    <string name="upstream_roaming_notification_message" msgid="7599056263326217523">"En itinérance, des frais supplémentaires peuvent s\'appliquer"</string>
+</resources>
diff --git a/Tethering/res/values-mcc311-mnc480-gl/strings.xml b/Tethering/res/values-mcc311-mnc480-gl/strings.xml
new file mode 100644
index 0000000..0c4195a
--- /dev/null
+++ b/Tethering/res/values-mcc311-mnc480-gl/strings.xml
@@ -0,0 +1,24 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!--  Copyright (C) 2020 The Android Open Source Project
+
+     Licensed under the Apache License, Version 2.0 (the "License");
+     you may not use this file except in compliance with the License.
+     You may obtain a copy of the License at
+
+          http://www.apache.org/licenses/LICENSE-2.0
+
+     Unless required by applicable law or agreed to in writing, software
+     distributed under the License is distributed on an "AS IS" BASIS,
+     WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+     See the License for the specific language governing permissions and
+     limitations under the License.
+ -->
+
+<resources xmlns:android="http://schemas.android.com/apk/res/android"
+    xmlns:xliff="urn:oasis:names:tc:xliff:document:1.2">
+    <string name="no_upstream_notification_title" msgid="611650570559011140">"A conexión compartida non ten Internet"</string>
+    <string name="no_upstream_notification_message" msgid="6508394877641864863">"Non se puideron conectar os dispositivos"</string>
+    <string name="no_upstream_notification_disable_button" msgid="7609346639290990508">"Desactivar conexión compartida"</string>
+    <string name="upstream_roaming_notification_title" msgid="6032901176124830787">"Está activada a zona wifi ou a conexión compartida"</string>
+    <string name="upstream_roaming_notification_message" msgid="7599056263326217523">"Pódense aplicar cargos adicionais en itinerancia"</string>
+</resources>
diff --git a/Tethering/res/values-mcc311-mnc480-gu/strings.xml b/Tethering/res/values-mcc311-mnc480-gu/strings.xml
new file mode 100644
index 0000000..e9d33a7
--- /dev/null
+++ b/Tethering/res/values-mcc311-mnc480-gu/strings.xml
@@ -0,0 +1,24 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!--  Copyright (C) 2020 The Android Open Source Project
+
+     Licensed under the Apache License, Version 2.0 (the "License");
+     you may not use this file except in compliance with the License.
+     You may obtain a copy of the License at
+
+          http://www.apache.org/licenses/LICENSE-2.0
+
+     Unless required by applicable law or agreed to in writing, software
+     distributed under the License is distributed on an "AS IS" BASIS,
+     WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+     See the License for the specific language governing permissions and
+     limitations under the License.
+ -->
+
+<resources xmlns:android="http://schemas.android.com/apk/res/android"
+    xmlns:xliff="urn:oasis:names:tc:xliff:document:1.2">
+    <string name="no_upstream_notification_title" msgid="611650570559011140">"ઇન્ટરનેટ શેર કરવાની સુવિધામાં ઇન્ટરનેટ નથી"</string>
+    <string name="no_upstream_notification_message" msgid="6508394877641864863">"ડિવાઇસ કનેક્ટ કરી શકાતા નથી"</string>
+    <string name="no_upstream_notification_disable_button" msgid="7609346639290990508">"ઇન્ટરનેટ શેર કરવાની સુવિધા બંધ કરો"</string>
+    <string name="upstream_roaming_notification_title" msgid="6032901176124830787">"હૉટસ્પૉટ અથવા ઇન્ટરનેટ શેર કરવાની સુવિધા ચાલુ છે"</string>
+    <string name="upstream_roaming_notification_message" msgid="7599056263326217523">"રોમિંગમાં વધારાના શુલ્ક લાગી શકે છે"</string>
+</resources>
diff --git a/Tethering/res/values-mcc311-mnc480-hi/strings.xml b/Tethering/res/values-mcc311-mnc480-hi/strings.xml
new file mode 100644
index 0000000..aa418ac
--- /dev/null
+++ b/Tethering/res/values-mcc311-mnc480-hi/strings.xml
@@ -0,0 +1,24 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!--  Copyright (C) 2020 The Android Open Source Project
+
+     Licensed under the Apache License, Version 2.0 (the "License");
+     you may not use this file except in compliance with the License.
+     You may obtain a copy of the License at
+
+          http://www.apache.org/licenses/LICENSE-2.0
+
+     Unless required by applicable law or agreed to in writing, software
+     distributed under the License is distributed on an "AS IS" BASIS,
+     WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+     See the License for the specific language governing permissions and
+     limitations under the License.
+ -->
+
+<resources xmlns:android="http://schemas.android.com/apk/res/android"
+    xmlns:xliff="urn:oasis:names:tc:xliff:document:1.2">
+    <string name="no_upstream_notification_title" msgid="611650570559011140">"टेदरिंग से इंटरनेट नहीं चल रहा"</string>
+    <string name="no_upstream_notification_message" msgid="6508394877641864863">"डिवाइस कनेक्ट नहीं हो पा रहे"</string>
+    <string name="no_upstream_notification_disable_button" msgid="7609346639290990508">"टेदरिंग बंद करें"</string>
+    <string name="upstream_roaming_notification_title" msgid="6032901176124830787">"हॉटस्पॉट या टेदरिंग चालू है"</string>
+    <string name="upstream_roaming_notification_message" msgid="7599056263326217523">"रोमिंग के दौरान अतिरिक्त शुल्क लग सकता है"</string>
+</resources>
diff --git a/Tethering/res/values-mcc311-mnc480-hr/strings.xml b/Tethering/res/values-mcc311-mnc480-hr/strings.xml
new file mode 100644
index 0000000..51c524a
--- /dev/null
+++ b/Tethering/res/values-mcc311-mnc480-hr/strings.xml
@@ -0,0 +1,24 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!--  Copyright (C) 2020 The Android Open Source Project
+
+     Licensed under the Apache License, Version 2.0 (the "License");
+     you may not use this file except in compliance with the License.
+     You may obtain a copy of the License at
+
+          http://www.apache.org/licenses/LICENSE-2.0
+
+     Unless required by applicable law or agreed to in writing, software
+     distributed under the License is distributed on an "AS IS" BASIS,
+     WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+     See the License for the specific language governing permissions and
+     limitations under the License.
+ -->
+
+<resources xmlns:android="http://schemas.android.com/apk/res/android"
+    xmlns:xliff="urn:oasis:names:tc:xliff:document:1.2">
+    <string name="no_upstream_notification_title" msgid="611650570559011140">"Modemsko povezivanje nema internet"</string>
+    <string name="no_upstream_notification_message" msgid="6508394877641864863">"Uređaji se ne mogu povezati"</string>
+    <string name="no_upstream_notification_disable_button" msgid="7609346639290990508">"Isključivanje modemskog povezivanja"</string>
+    <string name="upstream_roaming_notification_title" msgid="6032901176124830787">"Uključena je žarišna točka ili modemsko povezivanje"</string>
+    <string name="upstream_roaming_notification_message" msgid="7599056263326217523">"U roamingu su mogući dodatni troškovi"</string>
+</resources>
diff --git a/Tethering/res/values-mcc311-mnc480-hu/strings.xml b/Tethering/res/values-mcc311-mnc480-hu/strings.xml
new file mode 100644
index 0000000..164e45e
--- /dev/null
+++ b/Tethering/res/values-mcc311-mnc480-hu/strings.xml
@@ -0,0 +1,24 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!--  Copyright (C) 2020 The Android Open Source Project
+
+     Licensed under the Apache License, Version 2.0 (the "License");
+     you may not use this file except in compliance with the License.
+     You may obtain a copy of the License at
+
+          http://www.apache.org/licenses/LICENSE-2.0
+
+     Unless required by applicable law or agreed to in writing, software
+     distributed under the License is distributed on an "AS IS" BASIS,
+     WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+     See the License for the specific language governing permissions and
+     limitations under the License.
+ -->
+
+<resources xmlns:android="http://schemas.android.com/apk/res/android"
+    xmlns:xliff="urn:oasis:names:tc:xliff:document:1.2">
+    <string name="no_upstream_notification_title" msgid="611650570559011140">"Nincs internetkapcsolat az internet megosztásához"</string>
+    <string name="no_upstream_notification_message" msgid="6508394877641864863">"Az eszközök nem tudnak csatlakozni"</string>
+    <string name="no_upstream_notification_disable_button" msgid="7609346639290990508">"Internetmegosztás kikapcsolása"</string>
+    <string name="upstream_roaming_notification_title" msgid="6032901176124830787">"A hotspot vagy az internetmegosztás be van kapcsolva"</string>
+    <string name="upstream_roaming_notification_message" msgid="7599056263326217523">"Roaming során további díjak léphetnek fel"</string>
+</resources>
diff --git a/Tethering/res/values-mcc311-mnc480-hy/strings.xml b/Tethering/res/values-mcc311-mnc480-hy/strings.xml
new file mode 100644
index 0000000..e76c0a4
--- /dev/null
+++ b/Tethering/res/values-mcc311-mnc480-hy/strings.xml
@@ -0,0 +1,24 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!--  Copyright (C) 2020 The Android Open Source Project
+
+     Licensed under the Apache License, Version 2.0 (the "License");
+     you may not use this file except in compliance with the License.
+     You may obtain a copy of the License at
+
+          http://www.apache.org/licenses/LICENSE-2.0
+
+     Unless required by applicable law or agreed to in writing, software
+     distributed under the License is distributed on an "AS IS" BASIS,
+     WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+     See the License for the specific language governing permissions and
+     limitations under the License.
+ -->
+
+<resources xmlns:android="http://schemas.android.com/apk/res/android"
+    xmlns:xliff="urn:oasis:names:tc:xliff:document:1.2">
+    <string name="no_upstream_notification_title" msgid="611650570559011140">"Մոդեմի ռեժիմի կապը բացակայում է"</string>
+    <string name="no_upstream_notification_message" msgid="6508394877641864863">"Չհաջողվեց միացնել սարքը"</string>
+    <string name="no_upstream_notification_disable_button" msgid="7609346639290990508">"Անջատել մոդեմի ռեժիմը"</string>
+    <string name="upstream_roaming_notification_title" msgid="6032901176124830787">"Թեժ կետը կամ մոդեմի ռեժիմը միացված է"</string>
+    <string name="upstream_roaming_notification_message" msgid="7599056263326217523">"Ռոումինգում կարող են լրացուցիչ վճարներ գանձվել"</string>
+</resources>
diff --git a/Tethering/res/values-mcc311-mnc480-in/strings.xml b/Tethering/res/values-mcc311-mnc480-in/strings.xml
new file mode 100644
index 0000000..2b817f8
--- /dev/null
+++ b/Tethering/res/values-mcc311-mnc480-in/strings.xml
@@ -0,0 +1,24 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!--  Copyright (C) 2020 The Android Open Source Project
+
+     Licensed under the Apache License, Version 2.0 (the "License");
+     you may not use this file except in compliance with the License.
+     You may obtain a copy of the License at
+
+          http://www.apache.org/licenses/LICENSE-2.0
+
+     Unless required by applicable law or agreed to in writing, software
+     distributed under the License is distributed on an "AS IS" BASIS,
+     WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+     See the License for the specific language governing permissions and
+     limitations under the License.
+ -->
+
+<resources xmlns:android="http://schemas.android.com/apk/res/android"
+    xmlns:xliff="urn:oasis:names:tc:xliff:document:1.2">
+    <string name="no_upstream_notification_title" msgid="611650570559011140">"Tidak ada koneksi internet di tethering"</string>
+    <string name="no_upstream_notification_message" msgid="6508394877641864863">"Perangkat tidak dapat terhubung"</string>
+    <string name="no_upstream_notification_disable_button" msgid="7609346639290990508">"Nonaktifkan tethering"</string>
+    <string name="upstream_roaming_notification_title" msgid="6032901176124830787">"Hotspot atau tethering aktif"</string>
+    <string name="upstream_roaming_notification_message" msgid="7599056263326217523">"Biaya tambahan mungkin berlaku saat roaming"</string>
+</resources>
diff --git a/Tethering/res/values-mcc311-mnc480-is/strings.xml b/Tethering/res/values-mcc311-mnc480-is/strings.xml
new file mode 100644
index 0000000..a338d9c
--- /dev/null
+++ b/Tethering/res/values-mcc311-mnc480-is/strings.xml
@@ -0,0 +1,24 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!--  Copyright (C) 2020 The Android Open Source Project
+
+     Licensed under the Apache License, Version 2.0 (the "License");
+     you may not use this file except in compliance with the License.
+     You may obtain a copy of the License at
+
+          http://www.apache.org/licenses/LICENSE-2.0
+
+     Unless required by applicable law or agreed to in writing, software
+     distributed under the License is distributed on an "AS IS" BASIS,
+     WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+     See the License for the specific language governing permissions and
+     limitations under the License.
+ -->
+
+<resources xmlns:android="http://schemas.android.com/apk/res/android"
+    xmlns:xliff="urn:oasis:names:tc:xliff:document:1.2">
+    <string name="no_upstream_notification_title" msgid="611650570559011140">"Tjóðrun er ekki með internettengingu"</string>
+    <string name="no_upstream_notification_message" msgid="6508394877641864863">"Tæki geta ekki tengst"</string>
+    <string name="no_upstream_notification_disable_button" msgid="7609346639290990508">"Slökkva á tjóðrun"</string>
+    <string name="upstream_roaming_notification_title" msgid="6032901176124830787">"Kveikt er á heitum reit eða tjóðrun"</string>
+    <string name="upstream_roaming_notification_message" msgid="7599056263326217523">"Viðbótargjöld kunna að eiga við í reiki"</string>
+</resources>
diff --git a/Tethering/res/values-mcc311-mnc480-it/strings.xml b/Tethering/res/values-mcc311-mnc480-it/strings.xml
new file mode 100644
index 0000000..77769c2
--- /dev/null
+++ b/Tethering/res/values-mcc311-mnc480-it/strings.xml
@@ -0,0 +1,24 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!--  Copyright (C) 2020 The Android Open Source Project
+
+     Licensed under the Apache License, Version 2.0 (the "License");
+     you may not use this file except in compliance with the License.
+     You may obtain a copy of the License at
+
+          http://www.apache.org/licenses/LICENSE-2.0
+
+     Unless required by applicable law or agreed to in writing, software
+     distributed under the License is distributed on an "AS IS" BASIS,
+     WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+     See the License for the specific language governing permissions and
+     limitations under the License.
+ -->
+
+<resources xmlns:android="http://schemas.android.com/apk/res/android"
+    xmlns:xliff="urn:oasis:names:tc:xliff:document:1.2">
+    <string name="no_upstream_notification_title" msgid="611650570559011140">"Nessuna connessione a Internet per il tethering"</string>
+    <string name="no_upstream_notification_message" msgid="6508394877641864863">"Impossibile connettere i dispositivi"</string>
+    <string name="no_upstream_notification_disable_button" msgid="7609346639290990508">"Disattiva il tethering"</string>
+    <string name="upstream_roaming_notification_title" msgid="6032901176124830787">"Hotspot o tethering attivi"</string>
+    <string name="upstream_roaming_notification_message" msgid="7599056263326217523">"Potrebbero essere applicati costi aggiuntivi durante il roaming"</string>
+</resources>
diff --git a/Tethering/res/values-mcc311-mnc480-iw/strings.xml b/Tethering/res/values-mcc311-mnc480-iw/strings.xml
new file mode 100644
index 0000000..5267b51
--- /dev/null
+++ b/Tethering/res/values-mcc311-mnc480-iw/strings.xml
@@ -0,0 +1,24 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!--  Copyright (C) 2020 The Android Open Source Project
+
+     Licensed under the Apache License, Version 2.0 (the "License");
+     you may not use this file except in compliance with the License.
+     You may obtain a copy of the License at
+
+          http://www.apache.org/licenses/LICENSE-2.0
+
+     Unless required by applicable law or agreed to in writing, software
+     distributed under the License is distributed on an "AS IS" BASIS,
+     WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+     See the License for the specific language governing permissions and
+     limitations under the License.
+ -->
+
+<resources xmlns:android="http://schemas.android.com/apk/res/android"
+    xmlns:xliff="urn:oasis:names:tc:xliff:document:1.2">
+    <string name="no_upstream_notification_title" msgid="611650570559011140">"אי אפשר להפעיל את תכונת שיתוף האינטרנט בין מכשירים כי אין חיבור לאינטרנט"</string>
+    <string name="no_upstream_notification_message" msgid="6508394877641864863">"למכשירים אין אפשרות להתחבר"</string>
+    <string name="no_upstream_notification_disable_button" msgid="7609346639290990508">"השבתה של שיתוף האינטרנט בין מכשירים"</string>
+    <string name="upstream_roaming_notification_title" msgid="6032901176124830787">"תכונת הנקודה לשיתוף אינטרנט או תכונת שיתוף האינטרנט בין מכשירים פועלת"</string>
+    <string name="upstream_roaming_notification_message" msgid="7599056263326217523">"ייתכנו חיובים נוספים בעת נדידה"</string>
+</resources>
diff --git a/Tethering/res/values-mcc311-mnc480-ja/strings.xml b/Tethering/res/values-mcc311-mnc480-ja/strings.xml
new file mode 100644
index 0000000..66a9a6d
--- /dev/null
+++ b/Tethering/res/values-mcc311-mnc480-ja/strings.xml
@@ -0,0 +1,24 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!--  Copyright (C) 2020 The Android Open Source Project
+
+     Licensed under the Apache License, Version 2.0 (the "License");
+     you may not use this file except in compliance with the License.
+     You may obtain a copy of the License at
+
+          http://www.apache.org/licenses/LICENSE-2.0
+
+     Unless required by applicable law or agreed to in writing, software
+     distributed under the License is distributed on an "AS IS" BASIS,
+     WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+     See the License for the specific language governing permissions and
+     limitations under the License.
+ -->
+
+<resources xmlns:android="http://schemas.android.com/apk/res/android"
+    xmlns:xliff="urn:oasis:names:tc:xliff:document:1.2">
+    <string name="no_upstream_notification_title" msgid="611650570559011140">"テザリングがインターネットに接続されていません"</string>
+    <string name="no_upstream_notification_message" msgid="6508394877641864863">"デバイスを接続できません"</string>
+    <string name="no_upstream_notification_disable_button" msgid="7609346639290990508">"テザリングを OFF にする"</string>
+    <string name="upstream_roaming_notification_title" msgid="6032901176124830787">"アクセス ポイントまたはテザリングが ON です"</string>
+    <string name="upstream_roaming_notification_message" msgid="7599056263326217523">"ローミング時に追加料金が発生することがあります"</string>
+</resources>
diff --git a/Tethering/res/values-mcc311-mnc480-ka/strings.xml b/Tethering/res/values-mcc311-mnc480-ka/strings.xml
new file mode 100644
index 0000000..d8ad880
--- /dev/null
+++ b/Tethering/res/values-mcc311-mnc480-ka/strings.xml
@@ -0,0 +1,24 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!--  Copyright (C) 2020 The Android Open Source Project
+
+     Licensed under the Apache License, Version 2.0 (the "License");
+     you may not use this file except in compliance with the License.
+     You may obtain a copy of the License at
+
+          http://www.apache.org/licenses/LICENSE-2.0
+
+     Unless required by applicable law or agreed to in writing, software
+     distributed under the License is distributed on an "AS IS" BASIS,
+     WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+     See the License for the specific language governing permissions and
+     limitations under the License.
+ -->
+
+<resources xmlns:android="http://schemas.android.com/apk/res/android"
+    xmlns:xliff="urn:oasis:names:tc:xliff:document:1.2">
+    <string name="no_upstream_notification_title" msgid="611650570559011140">"ტეტერინგს არ აქვს ინტერნეტზე წვდომა"</string>
+    <string name="no_upstream_notification_message" msgid="6508394877641864863">"მოწყობილობები ვერ ახერხებენ დაკავშირებას"</string>
+    <string name="no_upstream_notification_disable_button" msgid="7609346639290990508">"ტეტერინგის გამორთვა"</string>
+    <string name="upstream_roaming_notification_title" msgid="6032901176124830787">"ჩართულია უსადენო ქსელი ან ტეტერინგი"</string>
+    <string name="upstream_roaming_notification_message" msgid="7599056263326217523">"როუმინგის გამოყენებისას შეიძლება ჩამოგეჭრათ დამატებითი საფასური"</string>
+</resources>
diff --git a/Tethering/res/values-mcc311-mnc480-kk/strings.xml b/Tethering/res/values-mcc311-mnc480-kk/strings.xml
new file mode 100644
index 0000000..1ddd6b4
--- /dev/null
+++ b/Tethering/res/values-mcc311-mnc480-kk/strings.xml
@@ -0,0 +1,24 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!--  Copyright (C) 2020 The Android Open Source Project
+
+     Licensed under the Apache License, Version 2.0 (the "License");
+     you may not use this file except in compliance with the License.
+     You may obtain a copy of the License at
+
+          http://www.apache.org/licenses/LICENSE-2.0
+
+     Unless required by applicable law or agreed to in writing, software
+     distributed under the License is distributed on an "AS IS" BASIS,
+     WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+     See the License for the specific language governing permissions and
+     limitations under the License.
+ -->
+
+<resources xmlns:android="http://schemas.android.com/apk/res/android"
+    xmlns:xliff="urn:oasis:names:tc:xliff:document:1.2">
+    <string name="no_upstream_notification_title" msgid="611650570559011140">"Тетеринг режимі интернет байланысынсыз пайдаланылуда"</string>
+    <string name="no_upstream_notification_message" msgid="6508394877641864863">"Құрылғыларды байланыстыру мүмкін емес"</string>
+    <string name="no_upstream_notification_disable_button" msgid="7609346639290990508">"Тетерингіні өшіру"</string>
+    <string name="upstream_roaming_notification_title" msgid="6032901176124830787">"Хотспот немесе тетеринг қосулы"</string>
+    <string name="upstream_roaming_notification_message" msgid="7599056263326217523">"Роуминг кезінде қосымша ақы алынуы мүмкін."</string>
+</resources>
diff --git a/Tethering/res/values-mcc311-mnc480-km/strings.xml b/Tethering/res/values-mcc311-mnc480-km/strings.xml
new file mode 100644
index 0000000..cf5a137
--- /dev/null
+++ b/Tethering/res/values-mcc311-mnc480-km/strings.xml
@@ -0,0 +1,24 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!--  Copyright (C) 2020 The Android Open Source Project
+
+     Licensed under the Apache License, Version 2.0 (the "License");
+     you may not use this file except in compliance with the License.
+     You may obtain a copy of the License at
+
+          http://www.apache.org/licenses/LICENSE-2.0
+
+     Unless required by applicable law or agreed to in writing, software
+     distributed under the License is distributed on an "AS IS" BASIS,
+     WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+     See the License for the specific language governing permissions and
+     limitations under the License.
+ -->
+
+<resources xmlns:android="http://schemas.android.com/apk/res/android"
+    xmlns:xliff="urn:oasis:names:tc:xliff:document:1.2">
+    <string name="no_upstream_notification_title" msgid="611650570559011140">"ការភ្ជាប់​មិនមានអ៊ីនធឺណិត​ទេ"</string>
+    <string name="no_upstream_notification_message" msgid="6508394877641864863">"មិនអាច​ភ្ជាប់ឧបករណ៍​បានទេ"</string>
+    <string name="no_upstream_notification_disable_button" msgid="7609346639290990508">"បិទការភ្ជាប់"</string>
+    <string name="upstream_roaming_notification_title" msgid="6032901176124830787">"ហតស្ប៉ត ឬការភ្ជាប់​ត្រូវបានបើក"</string>
+    <string name="upstream_roaming_notification_message" msgid="7599056263326217523">"អាចមាន​ការគិតថ្លៃ​បន្ថែម នៅពេល​រ៉ូមីង"</string>
+</resources>
diff --git a/Tethering/res/values-mcc311-mnc480-kn/strings.xml b/Tethering/res/values-mcc311-mnc480-kn/strings.xml
new file mode 100644
index 0000000..68ae68b
--- /dev/null
+++ b/Tethering/res/values-mcc311-mnc480-kn/strings.xml
@@ -0,0 +1,24 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!--  Copyright (C) 2020 The Android Open Source Project
+
+     Licensed under the Apache License, Version 2.0 (the "License");
+     you may not use this file except in compliance with the License.
+     You may obtain a copy of the License at
+
+          http://www.apache.org/licenses/LICENSE-2.0
+
+     Unless required by applicable law or agreed to in writing, software
+     distributed under the License is distributed on an "AS IS" BASIS,
+     WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+     See the License for the specific language governing permissions and
+     limitations under the License.
+ -->
+
+<resources xmlns:android="http://schemas.android.com/apk/res/android"
+    xmlns:xliff="urn:oasis:names:tc:xliff:document:1.2">
+    <string name="no_upstream_notification_title" msgid="611650570559011140">"ಟೆಥರಿಂಗ್‌ ಯಾವುದೇ ಇಂಟರ್ನೆಟ್ ಕನೆಕ್ಷನ್ ಹೊಂದಿಲ್ಲ"</string>
+    <string name="no_upstream_notification_message" msgid="6508394877641864863">"ಸಾಧನಗಳನ್ನು ಕನೆಕ್ಟ್ ಮಾಡಲು ಸಾಧ್ಯವಿಲ್ಲ"</string>
+    <string name="no_upstream_notification_disable_button" msgid="7609346639290990508">"ಟೆಥರಿಂಗ್‌ ಆಫ್ ಮಾಡಿ"</string>
+    <string name="upstream_roaming_notification_title" msgid="6032901176124830787">"ಹಾಟ್‌ಸ್ಪಾಟ್ ಅಥವಾ ಟೆಥರಿಂಗ್‌ ಆನ್ ಆಗಿದೆ"</string>
+    <string name="upstream_roaming_notification_message" msgid="7599056263326217523">"ರೋಮಿಂಗ್‌ನಲ್ಲಿರುವಾಗ ಹೆಚ್ಚುವರಿ ಶುಲ್ಕಗಳು ಅನ್ವಯವಾಗಬಹುದು"</string>
+</resources>
diff --git a/Tethering/res/values-mcc311-mnc480-ko/strings.xml b/Tethering/res/values-mcc311-mnc480-ko/strings.xml
new file mode 100644
index 0000000..17185ba
--- /dev/null
+++ b/Tethering/res/values-mcc311-mnc480-ko/strings.xml
@@ -0,0 +1,24 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!--  Copyright (C) 2020 The Android Open Source Project
+
+     Licensed under the Apache License, Version 2.0 (the "License");
+     you may not use this file except in compliance with the License.
+     You may obtain a copy of the License at
+
+          http://www.apache.org/licenses/LICENSE-2.0
+
+     Unless required by applicable law or agreed to in writing, software
+     distributed under the License is distributed on an "AS IS" BASIS,
+     WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+     See the License for the specific language governing permissions and
+     limitations under the License.
+ -->
+
+<resources xmlns:android="http://schemas.android.com/apk/res/android"
+    xmlns:xliff="urn:oasis:names:tc:xliff:document:1.2">
+    <string name="no_upstream_notification_title" msgid="611650570559011140">"테더링으로 인터넷을 사용할 수 없음"</string>
+    <string name="no_upstream_notification_message" msgid="6508394877641864863">"기기에서 연결할 수 없음"</string>
+    <string name="no_upstream_notification_disable_button" msgid="7609346639290990508">"테더링 사용 중지"</string>
+    <string name="upstream_roaming_notification_title" msgid="6032901176124830787">"핫스팟 또는 테더링 켜짐"</string>
+    <string name="upstream_roaming_notification_message" msgid="7599056263326217523">"로밍 중에는 추가 요금이 발생할 수 있습니다."</string>
+</resources>
diff --git a/Tethering/res/values-mcc311-mnc480-ky/strings.xml b/Tethering/res/values-mcc311-mnc480-ky/strings.xml
new file mode 100644
index 0000000..6a9fb98
--- /dev/null
+++ b/Tethering/res/values-mcc311-mnc480-ky/strings.xml
@@ -0,0 +1,24 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!--  Copyright (C) 2020 The Android Open Source Project
+
+     Licensed under the Apache License, Version 2.0 (the "License");
+     you may not use this file except in compliance with the License.
+     You may obtain a copy of the License at
+
+          http://www.apache.org/licenses/LICENSE-2.0
+
+     Unless required by applicable law or agreed to in writing, software
+     distributed under the License is distributed on an "AS IS" BASIS,
+     WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+     See the License for the specific language governing permissions and
+     limitations under the License.
+ -->
+
+<resources xmlns:android="http://schemas.android.com/apk/res/android"
+    xmlns:xliff="urn:oasis:names:tc:xliff:document:1.2">
+    <string name="no_upstream_notification_title" msgid="611650570559011140">"Модем режими Интернети жок колдонулууда"</string>
+    <string name="no_upstream_notification_message" msgid="6508394877641864863">"Түзмөктөр туташпай жатат"</string>
+    <string name="no_upstream_notification_disable_button" msgid="7609346639290990508">"Модем режимин өчүрүү"</string>
+    <string name="upstream_roaming_notification_title" msgid="6032901176124830787">"Байланыш түйүнү же модем режими күйүк"</string>
+    <string name="upstream_roaming_notification_message" msgid="7599056263326217523">"Роумингде кошумча акы алынышы мүмкүн"</string>
+</resources>
diff --git a/Tethering/res/values-mcc311-mnc480-lo/strings.xml b/Tethering/res/values-mcc311-mnc480-lo/strings.xml
new file mode 100644
index 0000000..bcc4b57
--- /dev/null
+++ b/Tethering/res/values-mcc311-mnc480-lo/strings.xml
@@ -0,0 +1,24 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!--  Copyright (C) 2020 The Android Open Source Project
+
+     Licensed under the Apache License, Version 2.0 (the "License");
+     you may not use this file except in compliance with the License.
+     You may obtain a copy of the License at
+
+          http://www.apache.org/licenses/LICENSE-2.0
+
+     Unless required by applicable law or agreed to in writing, software
+     distributed under the License is distributed on an "AS IS" BASIS,
+     WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+     See the License for the specific language governing permissions and
+     limitations under the License.
+ -->
+
+<resources xmlns:android="http://schemas.android.com/apk/res/android"
+    xmlns:xliff="urn:oasis:names:tc:xliff:document:1.2">
+    <string name="no_upstream_notification_title" msgid="611650570559011140">"ການປ່ອຍສັນຍານບໍ່ມີອິນເຕີເນັດ"</string>
+    <string name="no_upstream_notification_message" msgid="6508394877641864863">"ອຸປະກອນບໍ່ສາມາດເຊື່ອມຕໍ່ໄດ້"</string>
+    <string name="no_upstream_notification_disable_button" msgid="7609346639290990508">"ປິດການປ່ອຍສັນຍານ"</string>
+    <string name="upstream_roaming_notification_title" msgid="6032901176124830787">"ເປີດໃຊ້ຮັອດສະປອດ ຫຼື ການປ່ອຍສັນຍານຢູ່"</string>
+    <string name="upstream_roaming_notification_message" msgid="7599056263326217523">"ອາດມີຄ່າໃຊ້ຈ່າຍເພີ່ມເຕີມໃນລະຫວ່າງການໂຣມມິງ"</string>
+</resources>
diff --git a/Tethering/res/values-mcc311-mnc480-lt/strings.xml b/Tethering/res/values-mcc311-mnc480-lt/strings.xml
new file mode 100644
index 0000000..011c2c1
--- /dev/null
+++ b/Tethering/res/values-mcc311-mnc480-lt/strings.xml
@@ -0,0 +1,24 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!--  Copyright (C) 2020 The Android Open Source Project
+
+     Licensed under the Apache License, Version 2.0 (the "License");
+     you may not use this file except in compliance with the License.
+     You may obtain a copy of the License at
+
+          http://www.apache.org/licenses/LICENSE-2.0
+
+     Unless required by applicable law or agreed to in writing, software
+     distributed under the License is distributed on an "AS IS" BASIS,
+     WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+     See the License for the specific language governing permissions and
+     limitations under the License.
+ -->
+
+<resources xmlns:android="http://schemas.android.com/apk/res/android"
+    xmlns:xliff="urn:oasis:names:tc:xliff:document:1.2">
+    <string name="no_upstream_notification_title" msgid="611650570559011140">"Nėra įrenginio kaip modemo naudojimo interneto ryšio"</string>
+    <string name="no_upstream_notification_message" msgid="6508394877641864863">"Nepavyko susieti įrenginių"</string>
+    <string name="no_upstream_notification_disable_button" msgid="7609346639290990508">"Išjungti įrenginio kaip modemo naudojimą"</string>
+    <string name="upstream_roaming_notification_title" msgid="6032901176124830787">"Įjungtas viešosios interneto prieigos taškas arba įrenginio kaip modemo naudojimas"</string>
+    <string name="upstream_roaming_notification_message" msgid="7599056263326217523">"Veikiant tarptinkliniam ryšiui gali būti taikomi papildomi mokesčiai"</string>
+</resources>
diff --git a/Tethering/res/values-mcc311-mnc480-lv/strings.xml b/Tethering/res/values-mcc311-mnc480-lv/strings.xml
new file mode 100644
index 0000000..5cb2f3b
--- /dev/null
+++ b/Tethering/res/values-mcc311-mnc480-lv/strings.xml
@@ -0,0 +1,24 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!--  Copyright (C) 2020 The Android Open Source Project
+
+     Licensed under the Apache License, Version 2.0 (the "License");
+     you may not use this file except in compliance with the License.
+     You may obtain a copy of the License at
+
+          http://www.apache.org/licenses/LICENSE-2.0
+
+     Unless required by applicable law or agreed to in writing, software
+     distributed under the License is distributed on an "AS IS" BASIS,
+     WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+     See the License for the specific language governing permissions and
+     limitations under the License.
+ -->
+
+<resources xmlns:android="http://schemas.android.com/apk/res/android"
+    xmlns:xliff="urn:oasis:names:tc:xliff:document:1.2">
+    <string name="no_upstream_notification_title" msgid="611650570559011140">"Piesaistei nav interneta savienojuma"</string>
+    <string name="no_upstream_notification_message" msgid="6508394877641864863">"Nevar savienot ierīces"</string>
+    <string name="no_upstream_notification_disable_button" msgid="7609346639290990508">"Izslēgt piesaisti"</string>
+    <string name="upstream_roaming_notification_title" msgid="6032901176124830787">"Ir ieslēgts tīklājs vai piesaiste"</string>
+    <string name="upstream_roaming_notification_message" msgid="7599056263326217523">"Viesabonēšanas laikā var tikt piemērota papildu samaksa"</string>
+</resources>
diff --git a/Tethering/res/values-mcc311-mnc480-mk/strings.xml b/Tethering/res/values-mcc311-mnc480-mk/strings.xml
new file mode 100644
index 0000000..4cbfd88
--- /dev/null
+++ b/Tethering/res/values-mcc311-mnc480-mk/strings.xml
@@ -0,0 +1,24 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!--  Copyright (C) 2020 The Android Open Source Project
+
+     Licensed under the Apache License, Version 2.0 (the "License");
+     you may not use this file except in compliance with the License.
+     You may obtain a copy of the License at
+
+          http://www.apache.org/licenses/LICENSE-2.0
+
+     Unless required by applicable law or agreed to in writing, software
+     distributed under the License is distributed on an "AS IS" BASIS,
+     WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+     See the License for the specific language governing permissions and
+     limitations under the License.
+ -->
+
+<resources xmlns:android="http://schemas.android.com/apk/res/android"
+    xmlns:xliff="urn:oasis:names:tc:xliff:document:1.2">
+    <string name="no_upstream_notification_title" msgid="611650570559011140">"Нема интернет преку мобилен"</string>
+    <string name="no_upstream_notification_message" msgid="6508394877641864863">"Уредите не може да се поврзат"</string>
+    <string name="no_upstream_notification_disable_button" msgid="7609346639290990508">"Исклучи интернет преку мобилен"</string>
+    <string name="upstream_roaming_notification_title" msgid="6032901176124830787">"Точката на пристап или интернетот преку мобилен е вклучен"</string>
+    <string name="upstream_roaming_notification_message" msgid="7599056263326217523">"При роаминг може да се наплатат дополнителни трошоци"</string>
+</resources>
diff --git a/Tethering/res/values-mcc311-mnc480-ml/strings.xml b/Tethering/res/values-mcc311-mnc480-ml/strings.xml
new file mode 100644
index 0000000..9cf4eaf
--- /dev/null
+++ b/Tethering/res/values-mcc311-mnc480-ml/strings.xml
@@ -0,0 +1,24 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!--  Copyright (C) 2020 The Android Open Source Project
+
+     Licensed under the Apache License, Version 2.0 (the "License");
+     you may not use this file except in compliance with the License.
+     You may obtain a copy of the License at
+
+          http://www.apache.org/licenses/LICENSE-2.0
+
+     Unless required by applicable law or agreed to in writing, software
+     distributed under the License is distributed on an "AS IS" BASIS,
+     WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+     See the License for the specific language governing permissions and
+     limitations under the License.
+ -->
+
+<resources xmlns:android="http://schemas.android.com/apk/res/android"
+    xmlns:xliff="urn:oasis:names:tc:xliff:document:1.2">
+    <string name="no_upstream_notification_title" msgid="611650570559011140">"ടെതറിംഗിന് ഇന്റർനെറ്റ് ഇല്ല"</string>
+    <string name="no_upstream_notification_message" msgid="6508394877641864863">"ഉപകരണങ്ങൾ കണക്റ്റ് ചെയ്യാനാവില്ല"</string>
+    <string name="no_upstream_notification_disable_button" msgid="7609346639290990508">"ടെതറിംഗ് ഓഫാക്കുക"</string>
+    <string name="upstream_roaming_notification_title" msgid="6032901176124830787">"ഹോട്ട്‌സ്‌പോട്ട് അല്ലെങ്കിൽ ടെതറിംഗ് ഓണാണ്"</string>
+    <string name="upstream_roaming_notification_message" msgid="7599056263326217523">"റോമിംഗ് ചെയ്യുമ്പോൾ അധിക നിരക്കുകൾ ബാധകമായേക്കാം"</string>
+</resources>
diff --git a/Tethering/res/values-mcc311-mnc480-mn/strings.xml b/Tethering/res/values-mcc311-mnc480-mn/strings.xml
new file mode 100644
index 0000000..47c82c1
--- /dev/null
+++ b/Tethering/res/values-mcc311-mnc480-mn/strings.xml
@@ -0,0 +1,24 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!--  Copyright (C) 2020 The Android Open Source Project
+
+     Licensed under the Apache License, Version 2.0 (the "License");
+     you may not use this file except in compliance with the License.
+     You may obtain a copy of the License at
+
+          http://www.apache.org/licenses/LICENSE-2.0
+
+     Unless required by applicable law or agreed to in writing, software
+     distributed under the License is distributed on an "AS IS" BASIS,
+     WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+     See the License for the specific language governing permissions and
+     limitations under the License.
+ -->
+
+<resources xmlns:android="http://schemas.android.com/apk/res/android"
+    xmlns:xliff="urn:oasis:names:tc:xliff:document:1.2">
+    <string name="no_upstream_notification_title" msgid="611650570559011140">"Модемд интернэт алга байна"</string>
+    <string name="no_upstream_notification_message" msgid="6508394877641864863">"Төхөөрөмжүүд холбогдох боломжгүй байна"</string>
+    <string name="no_upstream_notification_disable_button" msgid="7609346639290990508">"Модем болгохыг унтраах"</string>
+    <string name="upstream_roaming_notification_title" msgid="6032901176124830787">"Сүлжээний цэг эсвэл модем болгох асаалттай байна"</string>
+    <string name="upstream_roaming_notification_message" msgid="7599056263326217523">"Роумингийн үеэр нэмэлт төлбөр нэхэмжилж болзошгүй"</string>
+</resources>
diff --git a/Tethering/res/values-mcc311-mnc480-mr/strings.xml b/Tethering/res/values-mcc311-mnc480-mr/strings.xml
new file mode 100644
index 0000000..ad9e809
--- /dev/null
+++ b/Tethering/res/values-mcc311-mnc480-mr/strings.xml
@@ -0,0 +1,24 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!--  Copyright (C) 2020 The Android Open Source Project
+
+     Licensed under the Apache License, Version 2.0 (the "License");
+     you may not use this file except in compliance with the License.
+     You may obtain a copy of the License at
+
+          http://www.apache.org/licenses/LICENSE-2.0
+
+     Unless required by applicable law or agreed to in writing, software
+     distributed under the License is distributed on an "AS IS" BASIS,
+     WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+     See the License for the specific language governing permissions and
+     limitations under the License.
+ -->
+
+<resources xmlns:android="http://schemas.android.com/apk/res/android"
+    xmlns:xliff="urn:oasis:names:tc:xliff:document:1.2">
+    <string name="no_upstream_notification_title" msgid="611650570559011140">"टेदरिंगला इंटरनेट नाही"</string>
+    <string name="no_upstream_notification_message" msgid="6508394877641864863">"डिव्हाइस कनेक्ट होऊ शकत नाहीत"</string>
+    <string name="no_upstream_notification_disable_button" msgid="7609346639290990508">"टेदरिंग बंद करा"</string>
+    <string name="upstream_roaming_notification_title" msgid="6032901176124830787">"हॉटस्पॉट किंवा टेदरिंग सुरू आहे"</string>
+    <string name="upstream_roaming_notification_message" msgid="7599056263326217523">"रोमिंगदरम्यान अतिरिक्त शुल्क लागू होऊ शकतात"</string>
+</resources>
diff --git a/Tethering/res/values-mcc311-mnc480-ms/strings.xml b/Tethering/res/values-mcc311-mnc480-ms/strings.xml
new file mode 100644
index 0000000..e708cb8
--- /dev/null
+++ b/Tethering/res/values-mcc311-mnc480-ms/strings.xml
@@ -0,0 +1,24 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!--  Copyright (C) 2020 The Android Open Source Project
+
+     Licensed under the Apache License, Version 2.0 (the "License");
+     you may not use this file except in compliance with the License.
+     You may obtain a copy of the License at
+
+          http://www.apache.org/licenses/LICENSE-2.0
+
+     Unless required by applicable law or agreed to in writing, software
+     distributed under the License is distributed on an "AS IS" BASIS,
+     WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+     See the License for the specific language governing permissions and
+     limitations under the License.
+ -->
+
+<resources xmlns:android="http://schemas.android.com/apk/res/android"
+    xmlns:xliff="urn:oasis:names:tc:xliff:document:1.2">
+    <string name="no_upstream_notification_title" msgid="611650570559011140">"Penambatan tiada Internet"</string>
+    <string name="no_upstream_notification_message" msgid="6508394877641864863">"Peranti tidak dapat disambungkan"</string>
+    <string name="no_upstream_notification_disable_button" msgid="7609346639290990508">"Matikan penambatan"</string>
+    <string name="upstream_roaming_notification_title" msgid="6032901176124830787">"Tempat liputan atau penambatan dihidupkan"</string>
+    <string name="upstream_roaming_notification_message" msgid="7599056263326217523">"Caj tambahan mungkin digunakan semasa perayauan"</string>
+</resources>
diff --git a/Tethering/res/values-mcc311-mnc480-my/strings.xml b/Tethering/res/values-mcc311-mnc480-my/strings.xml
new file mode 100644
index 0000000..ba54622
--- /dev/null
+++ b/Tethering/res/values-mcc311-mnc480-my/strings.xml
@@ -0,0 +1,24 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!--  Copyright (C) 2020 The Android Open Source Project
+
+     Licensed under the Apache License, Version 2.0 (the "License");
+     you may not use this file except in compliance with the License.
+     You may obtain a copy of the License at
+
+          http://www.apache.org/licenses/LICENSE-2.0
+
+     Unless required by applicable law or agreed to in writing, software
+     distributed under the License is distributed on an "AS IS" BASIS,
+     WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+     See the License for the specific language governing permissions and
+     limitations under the License.
+ -->
+
+<resources xmlns:android="http://schemas.android.com/apk/res/android"
+    xmlns:xliff="urn:oasis:names:tc:xliff:document:1.2">
+    <string name="no_upstream_notification_title" msgid="611650570559011140">"မိုဘိုင်းဖုန်းသုံး ချိတ်ဆက်မျှဝေခြင်းတွင် အင်တာနက် မရှိပါ"</string>
+    <string name="no_upstream_notification_message" msgid="6508394877641864863">"စက်များ ချိတ်ဆက်၍ မရပါ"</string>
+    <string name="no_upstream_notification_disable_button" msgid="7609346639290990508">"မိုဘိုင်းဖုန်းသုံး ချိတ်ဆက်မျှဝေခြင်း ပိတ်ရန်"</string>
+    <string name="upstream_roaming_notification_title" msgid="6032901176124830787">"ဟော့စပေါ့ (သို့) မိုဘိုင်းဖုန်းသုံး ချိတ်ဆက်မျှဝေခြင်း ဖွင့်ထားသည်"</string>
+    <string name="upstream_roaming_notification_message" msgid="7599056263326217523">"ပြင်ပကွန်ရက်နှင့် ချိတ်ဆက်သည့်အခါ နောက်ထပ်ကျသင့်မှုများ ရှိနိုင်သည်"</string>
+</resources>
diff --git a/Tethering/res/values-mcc311-mnc480-nb/strings.xml b/Tethering/res/values-mcc311-mnc480-nb/strings.xml
new file mode 100644
index 0000000..57db484
--- /dev/null
+++ b/Tethering/res/values-mcc311-mnc480-nb/strings.xml
@@ -0,0 +1,24 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!--  Copyright (C) 2020 The Android Open Source Project
+
+     Licensed under the Apache License, Version 2.0 (the "License");
+     you may not use this file except in compliance with the License.
+     You may obtain a copy of the License at
+
+          http://www.apache.org/licenses/LICENSE-2.0
+
+     Unless required by applicable law or agreed to in writing, software
+     distributed under the License is distributed on an "AS IS" BASIS,
+     WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+     See the License for the specific language governing permissions and
+     limitations under the License.
+ -->
+
+<resources xmlns:android="http://schemas.android.com/apk/res/android"
+    xmlns:xliff="urn:oasis:names:tc:xliff:document:1.2">
+    <string name="no_upstream_notification_title" msgid="611650570559011140">"Internettdeling har ikke internettilgang"</string>
+    <string name="no_upstream_notification_message" msgid="6508394877641864863">"Enhetene kan ikke koble til"</string>
+    <string name="no_upstream_notification_disable_button" msgid="7609346639290990508">"Slå av internettdeling"</string>
+    <string name="upstream_roaming_notification_title" msgid="6032901176124830787">"Wi-Fi-sone eller internettdeling er på"</string>
+    <string name="upstream_roaming_notification_message" msgid="7599056263326217523">"Ytterligere kostnader kan påløpe under roaming"</string>
+</resources>
diff --git a/Tethering/res/values-mcc311-mnc480-ne/strings.xml b/Tethering/res/values-mcc311-mnc480-ne/strings.xml
new file mode 100644
index 0000000..1503244
--- /dev/null
+++ b/Tethering/res/values-mcc311-mnc480-ne/strings.xml
@@ -0,0 +1,24 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!--  Copyright (C) 2020 The Android Open Source Project
+
+     Licensed under the Apache License, Version 2.0 (the "License");
+     you may not use this file except in compliance with the License.
+     You may obtain a copy of the License at
+
+          http://www.apache.org/licenses/LICENSE-2.0
+
+     Unless required by applicable law or agreed to in writing, software
+     distributed under the License is distributed on an "AS IS" BASIS,
+     WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+     See the License for the specific language governing permissions and
+     limitations under the License.
+ -->
+
+<resources xmlns:android="http://schemas.android.com/apk/res/android"
+    xmlns:xliff="urn:oasis:names:tc:xliff:document:1.2">
+    <string name="no_upstream_notification_title" msgid="611650570559011140">"टेदरिङमार्फत इन्टरनेट कनेक्सन प्राप्त हुन सकेन"</string>
+    <string name="no_upstream_notification_message" msgid="6508394877641864863">"यन्त्रहरू कनेक्ट गर्न सकिएन"</string>
+    <string name="no_upstream_notification_disable_button" msgid="7609346639290990508">"टेदरिङ निष्क्रिय पार्नुहोस्"</string>
+    <string name="upstream_roaming_notification_title" msgid="6032901176124830787">"हटस्पट वा टेदरिङ सक्रिय छ"</string>
+    <string name="upstream_roaming_notification_message" msgid="7599056263326217523">"रोमिङ सेवा प्रयोग गर्दा अतिरिक्त शुल्क लाग्न सक्छ"</string>
+</resources>
diff --git a/Tethering/res/values-mcc311-mnc480-nl/strings.xml b/Tethering/res/values-mcc311-mnc480-nl/strings.xml
new file mode 100644
index 0000000..b08133f
--- /dev/null
+++ b/Tethering/res/values-mcc311-mnc480-nl/strings.xml
@@ -0,0 +1,24 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!--  Copyright (C) 2020 The Android Open Source Project
+
+     Licensed under the Apache License, Version 2.0 (the "License");
+     you may not use this file except in compliance with the License.
+     You may obtain a copy of the License at
+
+          http://www.apache.org/licenses/LICENSE-2.0
+
+     Unless required by applicable law or agreed to in writing, software
+     distributed under the License is distributed on an "AS IS" BASIS,
+     WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+     See the License for the specific language governing permissions and
+     limitations under the License.
+ -->
+
+<resources xmlns:android="http://schemas.android.com/apk/res/android"
+    xmlns:xliff="urn:oasis:names:tc:xliff:document:1.2">
+    <string name="no_upstream_notification_title" msgid="611650570559011140">"Tethering heeft geen internet"</string>
+    <string name="no_upstream_notification_message" msgid="6508394877641864863">"Apparaten kunnen niet worden verbonden"</string>
+    <string name="no_upstream_notification_disable_button" msgid="7609346639290990508">"Tethering uitschakelen"</string>
+    <string name="upstream_roaming_notification_title" msgid="6032901176124830787">"Hotspot of tethering is ingeschakeld"</string>
+    <string name="upstream_roaming_notification_message" msgid="7599056263326217523">"Er kunnen extra kosten voor roaming in rekening worden gebracht."</string>
+</resources>
diff --git a/Tethering/res/values-mcc311-mnc480-or/strings.xml b/Tethering/res/values-mcc311-mnc480-or/strings.xml
new file mode 100644
index 0000000..1ad4ca3
--- /dev/null
+++ b/Tethering/res/values-mcc311-mnc480-or/strings.xml
@@ -0,0 +1,24 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!--  Copyright (C) 2020 The Android Open Source Project
+
+     Licensed under the Apache License, Version 2.0 (the "License");
+     you may not use this file except in compliance with the License.
+     You may obtain a copy of the License at
+
+          http://www.apache.org/licenses/LICENSE-2.0
+
+     Unless required by applicable law or agreed to in writing, software
+     distributed under the License is distributed on an "AS IS" BASIS,
+     WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+     See the License for the specific language governing permissions and
+     limitations under the License.
+ -->
+
+<resources xmlns:android="http://schemas.android.com/apk/res/android"
+    xmlns:xliff="urn:oasis:names:tc:xliff:document:1.2">
+    <string name="no_upstream_notification_title" msgid="611650570559011140">"ଟିଥରିଂ ପାଇଁ କୌଣସି ଇଣ୍ଟର୍ନେଟ୍ ସଂଯୋଗ ନାହିଁ"</string>
+    <string name="no_upstream_notification_message" msgid="6508394877641864863">"ଡିଭାଇସଗୁଡ଼ିକ ସଂଯୋଗ କରାଯାଇପାରିବ ନାହିଁ"</string>
+    <string name="no_upstream_notification_disable_button" msgid="7609346639290990508">"ଟିଥରିଂ ବନ୍ଦ କରନ୍ତୁ"</string>
+    <string name="upstream_roaming_notification_title" msgid="6032901176124830787">"ହଟସ୍ପଟ୍ କିମ୍ବା ଟିଥରିଂ ଚାଲୁ ଅଛି"</string>
+    <string name="upstream_roaming_notification_message" msgid="7599056263326217523">"ରୋମିଂରେ ଥିବା ସମୟରେ ଅତିରିକ୍ତ ଶୁଳ୍କ ଲାଗୁ ହୋଇପାରେ"</string>
+</resources>
diff --git a/Tethering/res/values-mcc311-mnc480-pa/strings.xml b/Tethering/res/values-mcc311-mnc480-pa/strings.xml
new file mode 100644
index 0000000..88def56
--- /dev/null
+++ b/Tethering/res/values-mcc311-mnc480-pa/strings.xml
@@ -0,0 +1,24 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!--  Copyright (C) 2020 The Android Open Source Project
+
+     Licensed under the Apache License, Version 2.0 (the "License");
+     you may not use this file except in compliance with the License.
+     You may obtain a copy of the License at
+
+          http://www.apache.org/licenses/LICENSE-2.0
+
+     Unless required by applicable law or agreed to in writing, software
+     distributed under the License is distributed on an "AS IS" BASIS,
+     WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+     See the License for the specific language governing permissions and
+     limitations under the License.
+ -->
+
+<resources xmlns:android="http://schemas.android.com/apk/res/android"
+    xmlns:xliff="urn:oasis:names:tc:xliff:document:1.2">
+    <string name="no_upstream_notification_title" msgid="611650570559011140">"ਟੈਦਰਿੰਗ ਕੋਲ ਇੰਟਰਨੈੱਟ ਪਹੁੰਚ ਨਹੀਂ ਹੈ"</string>
+    <string name="no_upstream_notification_message" msgid="6508394877641864863">"ਡੀਵਾਈਸ ਕਨੈਕਟ ਨਹੀਂ ਕੀਤੇ ਜਾ ਸਕਦੇ"</string>
+    <string name="no_upstream_notification_disable_button" msgid="7609346639290990508">"ਟੈਦਰਿੰਗ ਬੰਦ ਕਰੋ"</string>
+    <string name="upstream_roaming_notification_title" msgid="6032901176124830787">"ਹੌਟਸਪੌਟ ਜਾਂ ਟੈਦਰਿੰਗ ਚਾਲੂ ਹੈ"</string>
+    <string name="upstream_roaming_notification_message" msgid="7599056263326217523">"ਰੋਮਿੰਗ ਦੌਰਾਨ ਵਧੀਕ ਖਰਚੇ ਲਾਗੂ ਹੋ ਸਕਦੇ ਹਨ"</string>
+</resources>
diff --git a/Tethering/res/values-mcc311-mnc480-pl/strings.xml b/Tethering/res/values-mcc311-mnc480-pl/strings.xml
new file mode 100644
index 0000000..f9890ab
--- /dev/null
+++ b/Tethering/res/values-mcc311-mnc480-pl/strings.xml
@@ -0,0 +1,24 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!--  Copyright (C) 2020 The Android Open Source Project
+
+     Licensed under the Apache License, Version 2.0 (the "License");
+     you may not use this file except in compliance with the License.
+     You may obtain a copy of the License at
+
+          http://www.apache.org/licenses/LICENSE-2.0
+
+     Unless required by applicable law or agreed to in writing, software
+     distributed under the License is distributed on an "AS IS" BASIS,
+     WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+     See the License for the specific language governing permissions and
+     limitations under the License.
+ -->
+
+<resources xmlns:android="http://schemas.android.com/apk/res/android"
+    xmlns:xliff="urn:oasis:names:tc:xliff:document:1.2">
+    <string name="no_upstream_notification_title" msgid="611650570559011140">"Tethering nie ma internetu"</string>
+    <string name="no_upstream_notification_message" msgid="6508394877641864863">"Urządzenia nie mogą się połączyć"</string>
+    <string name="no_upstream_notification_disable_button" msgid="7609346639290990508">"Wyłącz tethering"</string>
+    <string name="upstream_roaming_notification_title" msgid="6032901176124830787">"Hotspot lub tethering jest włączony"</string>
+    <string name="upstream_roaming_notification_message" msgid="7599056263326217523">"Podczas korzystania z roamingu mogą zostać naliczone dodatkowe opłaty"</string>
+</resources>
diff --git a/Tethering/res/values-mcc311-mnc480-pt-rBR/strings.xml b/Tethering/res/values-mcc311-mnc480-pt-rBR/strings.xml
new file mode 100644
index 0000000..ce3b884
--- /dev/null
+++ b/Tethering/res/values-mcc311-mnc480-pt-rBR/strings.xml
@@ -0,0 +1,24 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!--  Copyright (C) 2020 The Android Open Source Project
+
+     Licensed under the Apache License, Version 2.0 (the "License");
+     you may not use this file except in compliance with the License.
+     You may obtain a copy of the License at
+
+          http://www.apache.org/licenses/LICENSE-2.0
+
+     Unless required by applicable law or agreed to in writing, software
+     distributed under the License is distributed on an "AS IS" BASIS,
+     WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+     See the License for the specific language governing permissions and
+     limitations under the License.
+ -->
+
+<resources xmlns:android="http://schemas.android.com/apk/res/android"
+    xmlns:xliff="urn:oasis:names:tc:xliff:document:1.2">
+    <string name="no_upstream_notification_title" msgid="611650570559011140">"O tethering não tem Internet"</string>
+    <string name="no_upstream_notification_message" msgid="6508394877641864863">"Não é possível conectar os dispositivos"</string>
+    <string name="no_upstream_notification_disable_button" msgid="7609346639290990508">"Desativar o tethering"</string>
+    <string name="upstream_roaming_notification_title" msgid="6032901176124830787">"Ponto de acesso ou tethering ativado"</string>
+    <string name="upstream_roaming_notification_message" msgid="7599056263326217523">"Pode haver cobranças extras durante o roaming"</string>
+</resources>
diff --git a/Tethering/res/values-mcc311-mnc480-pt-rPT/strings.xml b/Tethering/res/values-mcc311-mnc480-pt-rPT/strings.xml
new file mode 100644
index 0000000..7e883ea
--- /dev/null
+++ b/Tethering/res/values-mcc311-mnc480-pt-rPT/strings.xml
@@ -0,0 +1,24 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!--  Copyright (C) 2020 The Android Open Source Project
+
+     Licensed under the Apache License, Version 2.0 (the "License");
+     you may not use this file except in compliance with the License.
+     You may obtain a copy of the License at
+
+          http://www.apache.org/licenses/LICENSE-2.0
+
+     Unless required by applicable law or agreed to in writing, software
+     distributed under the License is distributed on an "AS IS" BASIS,
+     WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+     See the License for the specific language governing permissions and
+     limitations under the License.
+ -->
+
+<resources xmlns:android="http://schemas.android.com/apk/res/android"
+    xmlns:xliff="urn:oasis:names:tc:xliff:document:1.2">
+    <string name="no_upstream_notification_title" msgid="611650570559011140">"A ligação (à Internet) via telemóvel não tem Internet"</string>
+    <string name="no_upstream_notification_message" msgid="6508394877641864863">"Não é possível ligar os dispositivos"</string>
+    <string name="no_upstream_notification_disable_button" msgid="7609346639290990508">"Desativar ligação (à Internet) via telemóvel"</string>
+    <string name="upstream_roaming_notification_title" msgid="6032901176124830787">"A zona Wi-Fi ou a ligação (à Internet) via telemóvel está ativada"</string>
+    <string name="upstream_roaming_notification_message" msgid="7599056263326217523">"Podem aplicar-se custos adicionais em roaming."</string>
+</resources>
diff --git a/Tethering/res/values-mcc311-mnc480-pt/strings.xml b/Tethering/res/values-mcc311-mnc480-pt/strings.xml
new file mode 100644
index 0000000..ce3b884
--- /dev/null
+++ b/Tethering/res/values-mcc311-mnc480-pt/strings.xml
@@ -0,0 +1,24 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!--  Copyright (C) 2020 The Android Open Source Project
+
+     Licensed under the Apache License, Version 2.0 (the "License");
+     you may not use this file except in compliance with the License.
+     You may obtain a copy of the License at
+
+          http://www.apache.org/licenses/LICENSE-2.0
+
+     Unless required by applicable law or agreed to in writing, software
+     distributed under the License is distributed on an "AS IS" BASIS,
+     WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+     See the License for the specific language governing permissions and
+     limitations under the License.
+ -->
+
+<resources xmlns:android="http://schemas.android.com/apk/res/android"
+    xmlns:xliff="urn:oasis:names:tc:xliff:document:1.2">
+    <string name="no_upstream_notification_title" msgid="611650570559011140">"O tethering não tem Internet"</string>
+    <string name="no_upstream_notification_message" msgid="6508394877641864863">"Não é possível conectar os dispositivos"</string>
+    <string name="no_upstream_notification_disable_button" msgid="7609346639290990508">"Desativar o tethering"</string>
+    <string name="upstream_roaming_notification_title" msgid="6032901176124830787">"Ponto de acesso ou tethering ativado"</string>
+    <string name="upstream_roaming_notification_message" msgid="7599056263326217523">"Pode haver cobranças extras durante o roaming"</string>
+</resources>
diff --git a/Tethering/res/values-mcc311-mnc480-ro/strings.xml b/Tethering/res/values-mcc311-mnc480-ro/strings.xml
new file mode 100644
index 0000000..1009417
--- /dev/null
+++ b/Tethering/res/values-mcc311-mnc480-ro/strings.xml
@@ -0,0 +1,24 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!--  Copyright (C) 2020 The Android Open Source Project
+
+     Licensed under the Apache License, Version 2.0 (the "License");
+     you may not use this file except in compliance with the License.
+     You may obtain a copy of the License at
+
+          http://www.apache.org/licenses/LICENSE-2.0
+
+     Unless required by applicable law or agreed to in writing, software
+     distributed under the License is distributed on an "AS IS" BASIS,
+     WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+     See the License for the specific language governing permissions and
+     limitations under the License.
+ -->
+
+<resources xmlns:android="http://schemas.android.com/apk/res/android"
+    xmlns:xliff="urn:oasis:names:tc:xliff:document:1.2">
+    <string name="no_upstream_notification_title" msgid="611650570559011140">"Procesul de tethering nu are internet"</string>
+    <string name="no_upstream_notification_message" msgid="6508394877641864863">"Dispozitivele nu se pot conecta"</string>
+    <string name="no_upstream_notification_disable_button" msgid="7609346639290990508">"Dezactivați procesul de tethering"</string>
+    <string name="upstream_roaming_notification_title" msgid="6032901176124830787">"S-a activat hotspotul sau tethering"</string>
+    <string name="upstream_roaming_notification_message" msgid="7599056263326217523">"Se pot aplica taxe suplimentare pentru roaming"</string>
+</resources>
diff --git a/Tethering/res/values-mcc311-mnc480-ru/strings.xml b/Tethering/res/values-mcc311-mnc480-ru/strings.xml
new file mode 100644
index 0000000..88683be
--- /dev/null
+++ b/Tethering/res/values-mcc311-mnc480-ru/strings.xml
@@ -0,0 +1,24 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!--  Copyright (C) 2020 The Android Open Source Project
+
+     Licensed under the Apache License, Version 2.0 (the "License");
+     you may not use this file except in compliance with the License.
+     You may obtain a copy of the License at
+
+          http://www.apache.org/licenses/LICENSE-2.0
+
+     Unless required by applicable law or agreed to in writing, software
+     distributed under the License is distributed on an "AS IS" BASIS,
+     WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+     See the License for the specific language governing permissions and
+     limitations under the License.
+ -->
+
+<resources xmlns:android="http://schemas.android.com/apk/res/android"
+    xmlns:xliff="urn:oasis:names:tc:xliff:document:1.2">
+    <string name="no_upstream_notification_title" msgid="611650570559011140">"Режим модема используется без доступа к Интернету"</string>
+    <string name="no_upstream_notification_message" msgid="6508394877641864863">"Невозможно подключить устройства."</string>
+    <string name="no_upstream_notification_disable_button" msgid="7609346639290990508">"Отключить режим модема"</string>
+    <string name="upstream_roaming_notification_title" msgid="6032901176124830787">"Включены точка доступа или режим модема"</string>
+    <string name="upstream_roaming_notification_message" msgid="7599056263326217523">"За использование услуг связи в роуминге может взиматься дополнительная плата."</string>
+</resources>
diff --git a/Tethering/res/values-mcc311-mnc480-si/strings.xml b/Tethering/res/values-mcc311-mnc480-si/strings.xml
new file mode 100644
index 0000000..176bcdb
--- /dev/null
+++ b/Tethering/res/values-mcc311-mnc480-si/strings.xml
@@ -0,0 +1,24 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!--  Copyright (C) 2020 The Android Open Source Project
+
+     Licensed under the Apache License, Version 2.0 (the "License");
+     you may not use this file except in compliance with the License.
+     You may obtain a copy of the License at
+
+          http://www.apache.org/licenses/LICENSE-2.0
+
+     Unless required by applicable law or agreed to in writing, software
+     distributed under the License is distributed on an "AS IS" BASIS,
+     WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+     See the License for the specific language governing permissions and
+     limitations under the License.
+ -->
+
+<resources xmlns:android="http://schemas.android.com/apk/res/android"
+    xmlns:xliff="urn:oasis:names:tc:xliff:document:1.2">
+    <string name="no_upstream_notification_title" msgid="611650570559011140">"ටෙදරින් හට අන්තර්ජාලය නැත"</string>
+    <string name="no_upstream_notification_message" msgid="6508394877641864863">"උපාංගවලට සම්බන්ධ විය නොහැකිය"</string>
+    <string name="no_upstream_notification_disable_button" msgid="7609346639290990508">"ටෙදරින් ක්‍රියාවිරහිත කරන්න"</string>
+    <string name="upstream_roaming_notification_title" msgid="6032901176124830787">"හොට්ස්පොට් හෝ ටෙදරින් ක්‍රියාත්මකයි"</string>
+    <string name="upstream_roaming_notification_message" msgid="7599056263326217523">"රෝමිං අතරතුර අමතර ගාස්තු අදාළ විය හැකිය"</string>
+</resources>
diff --git a/Tethering/res/values-mcc311-mnc480-sk/strings.xml b/Tethering/res/values-mcc311-mnc480-sk/strings.xml
new file mode 100644
index 0000000..b9e2127
--- /dev/null
+++ b/Tethering/res/values-mcc311-mnc480-sk/strings.xml
@@ -0,0 +1,24 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!--  Copyright (C) 2020 The Android Open Source Project
+
+     Licensed under the Apache License, Version 2.0 (the "License");
+     you may not use this file except in compliance with the License.
+     You may obtain a copy of the License at
+
+          http://www.apache.org/licenses/LICENSE-2.0
+
+     Unless required by applicable law or agreed to in writing, software
+     distributed under the License is distributed on an "AS IS" BASIS,
+     WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+     See the License for the specific language governing permissions and
+     limitations under the License.
+ -->
+
+<resources xmlns:android="http://schemas.android.com/apk/res/android"
+    xmlns:xliff="urn:oasis:names:tc:xliff:document:1.2">
+    <string name="no_upstream_notification_title" msgid="611650570559011140">"Tethering nemá internetové pripojenie"</string>
+    <string name="no_upstream_notification_message" msgid="6508394877641864863">"Zariadenia sa nemôžu pripojiť"</string>
+    <string name="no_upstream_notification_disable_button" msgid="7609346639290990508">"Vypnúť tethering"</string>
+    <string name="upstream_roaming_notification_title" msgid="6032901176124830787">"Je zapnutý hotspot alebo tethering"</string>
+    <string name="upstream_roaming_notification_message" msgid="7599056263326217523">"Počas roamingu vám môžu byť účtované ďalšie poplatky"</string>
+</resources>
diff --git a/Tethering/res/values-mcc311-mnc480-sl/strings.xml b/Tethering/res/values-mcc311-mnc480-sl/strings.xml
new file mode 100644
index 0000000..e8140e6
--- /dev/null
+++ b/Tethering/res/values-mcc311-mnc480-sl/strings.xml
@@ -0,0 +1,24 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!--  Copyright (C) 2020 The Android Open Source Project
+
+     Licensed under the Apache License, Version 2.0 (the "License");
+     you may not use this file except in compliance with the License.
+     You may obtain a copy of the License at
+
+          http://www.apache.org/licenses/LICENSE-2.0
+
+     Unless required by applicable law or agreed to in writing, software
+     distributed under the License is distributed on an "AS IS" BASIS,
+     WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+     See the License for the specific language governing permissions and
+     limitations under the License.
+ -->
+
+<resources xmlns:android="http://schemas.android.com/apk/res/android"
+    xmlns:xliff="urn:oasis:names:tc:xliff:document:1.2">
+    <string name="no_upstream_notification_title" msgid="611650570559011140">"Internetna povezava prek mobilnega telefona ni vzpostavljena"</string>
+    <string name="no_upstream_notification_message" msgid="6508394877641864863">"Napravi se ne moreta povezati"</string>
+    <string name="no_upstream_notification_disable_button" msgid="7609346639290990508">"Izklopi internetno povezavo prek mobilnega telefona"</string>
+    <string name="upstream_roaming_notification_title" msgid="6032901176124830787">"Dostopna točka ali internetna povezava prek mobilnega telefona je vklopljena"</string>
+    <string name="upstream_roaming_notification_message" msgid="7599056263326217523">"Med gostovanjem lahko nastanejo dodatni stroški"</string>
+</resources>
diff --git a/Tethering/res/values-mcc311-mnc480-sq/strings.xml b/Tethering/res/values-mcc311-mnc480-sq/strings.xml
new file mode 100644
index 0000000..61e698d
--- /dev/null
+++ b/Tethering/res/values-mcc311-mnc480-sq/strings.xml
@@ -0,0 +1,24 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!--  Copyright (C) 2020 The Android Open Source Project
+
+     Licensed under the Apache License, Version 2.0 (the "License");
+     you may not use this file except in compliance with the License.
+     You may obtain a copy of the License at
+
+          http://www.apache.org/licenses/LICENSE-2.0
+
+     Unless required by applicable law or agreed to in writing, software
+     distributed under the License is distributed on an "AS IS" BASIS,
+     WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+     See the License for the specific language governing permissions and
+     limitations under the License.
+ -->
+
+<resources xmlns:android="http://schemas.android.com/apk/res/android"
+    xmlns:xliff="urn:oasis:names:tc:xliff:document:1.2">
+    <string name="no_upstream_notification_title" msgid="611650570559011140">"Ndarja e internetit nuk ka internet"</string>
+    <string name="no_upstream_notification_message" msgid="6508394877641864863">"Pajisjet nuk mund të lidhen"</string>
+    <string name="no_upstream_notification_disable_button" msgid="7609346639290990508">"Çaktivizo ndarjen e internetit"</string>
+    <string name="upstream_roaming_notification_title" msgid="6032901176124830787">"Zona e qasjes për internet ose ndarja e internetit është aktive"</string>
+    <string name="upstream_roaming_notification_message" msgid="7599056263326217523">"Mund të zbatohen tarifime shtesë kur je në roaming"</string>
+</resources>
diff --git a/Tethering/res/values-mcc311-mnc480-sr/strings.xml b/Tethering/res/values-mcc311-mnc480-sr/strings.xml
new file mode 100644
index 0000000..b4c411c
--- /dev/null
+++ b/Tethering/res/values-mcc311-mnc480-sr/strings.xml
@@ -0,0 +1,24 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!--  Copyright (C) 2020 The Android Open Source Project
+
+     Licensed under the Apache License, Version 2.0 (the "License");
+     you may not use this file except in compliance with the License.
+     You may obtain a copy of the License at
+
+          http://www.apache.org/licenses/LICENSE-2.0
+
+     Unless required by applicable law or agreed to in writing, software
+     distributed under the License is distributed on an "AS IS" BASIS,
+     WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+     See the License for the specific language governing permissions and
+     limitations under the License.
+ -->
+
+<resources xmlns:android="http://schemas.android.com/apk/res/android"
+    xmlns:xliff="urn:oasis:names:tc:xliff:document:1.2">
+    <string name="no_upstream_notification_title" msgid="611650570559011140">"Привезивање нема приступ интернету"</string>
+    <string name="no_upstream_notification_message" msgid="6508394877641864863">"Повезивање уређаја није успело"</string>
+    <string name="no_upstream_notification_disable_button" msgid="7609346639290990508">"Искључи привезивање"</string>
+    <string name="upstream_roaming_notification_title" msgid="6032901176124830787">"Укључен је хотспот или привезивање"</string>
+    <string name="upstream_roaming_notification_message" msgid="7599056263326217523">"Можда важе додатни трошкови у ромингу"</string>
+</resources>
diff --git a/Tethering/res/values-mcc311-mnc480-sv/strings.xml b/Tethering/res/values-mcc311-mnc480-sv/strings.xml
new file mode 100644
index 0000000..4f543e4
--- /dev/null
+++ b/Tethering/res/values-mcc311-mnc480-sv/strings.xml
@@ -0,0 +1,24 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!--  Copyright (C) 2020 The Android Open Source Project
+
+     Licensed under the Apache License, Version 2.0 (the "License");
+     you may not use this file except in compliance with the License.
+     You may obtain a copy of the License at
+
+          http://www.apache.org/licenses/LICENSE-2.0
+
+     Unless required by applicable law or agreed to in writing, software
+     distributed under the License is distributed on an "AS IS" BASIS,
+     WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+     See the License for the specific language governing permissions and
+     limitations under the License.
+ -->
+
+<resources xmlns:android="http://schemas.android.com/apk/res/android"
+    xmlns:xliff="urn:oasis:names:tc:xliff:document:1.2">
+    <string name="no_upstream_notification_title" msgid="611650570559011140">"Det finns ingen internetanslutning för internetdelningen"</string>
+    <string name="no_upstream_notification_message" msgid="6508394877641864863">"Enheterna kan inte anslutas"</string>
+    <string name="no_upstream_notification_disable_button" msgid="7609346639290990508">"Inaktivera internetdelning"</string>
+    <string name="upstream_roaming_notification_title" msgid="6032901176124830787">"Surfzon eller internetdelning har aktiverats"</string>
+    <string name="upstream_roaming_notification_message" msgid="7599056263326217523">"Ytterligare avgifter kan tillkomma vid roaming"</string>
+</resources>
diff --git a/Tethering/res/values-mcc311-mnc480-sw/strings.xml b/Tethering/res/values-mcc311-mnc480-sw/strings.xml
new file mode 100644
index 0000000..ac347ab
--- /dev/null
+++ b/Tethering/res/values-mcc311-mnc480-sw/strings.xml
@@ -0,0 +1,24 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!--  Copyright (C) 2020 The Android Open Source Project
+
+     Licensed under the Apache License, Version 2.0 (the "License");
+     you may not use this file except in compliance with the License.
+     You may obtain a copy of the License at
+
+          http://www.apache.org/licenses/LICENSE-2.0
+
+     Unless required by applicable law or agreed to in writing, software
+     distributed under the License is distributed on an "AS IS" BASIS,
+     WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+     See the License for the specific language governing permissions and
+     limitations under the License.
+ -->
+
+<resources xmlns:android="http://schemas.android.com/apk/res/android"
+    xmlns:xliff="urn:oasis:names:tc:xliff:document:1.2">
+    <string name="no_upstream_notification_title" msgid="611650570559011140">"Kipengele cha kusambaza mtandao hakina intaneti"</string>
+    <string name="no_upstream_notification_message" msgid="6508394877641864863">"Imeshindwa kuunganisha vifaa"</string>
+    <string name="no_upstream_notification_disable_button" msgid="7609346639290990508">"Zima kipengele cha kusambaza mtandao"</string>
+    <string name="upstream_roaming_notification_title" msgid="6032901176124830787">"Umewasha kipengele cha kusambaza mtandao au mtandao pepe"</string>
+    <string name="upstream_roaming_notification_message" msgid="7599056263326217523">"Huenda ukatozwa gharama za ziada ukitumia mitandao ya ng\'ambo"</string>
+</resources>
diff --git a/Tethering/res/values-mcc311-mnc480-ta/strings.xml b/Tethering/res/values-mcc311-mnc480-ta/strings.xml
new file mode 100644
index 0000000..2ea2467
--- /dev/null
+++ b/Tethering/res/values-mcc311-mnc480-ta/strings.xml
@@ -0,0 +1,24 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!--  Copyright (C) 2020 The Android Open Source Project
+
+     Licensed under the Apache License, Version 2.0 (the "License");
+     you may not use this file except in compliance with the License.
+     You may obtain a copy of the License at
+
+          http://www.apache.org/licenses/LICENSE-2.0
+
+     Unless required by applicable law or agreed to in writing, software
+     distributed under the License is distributed on an "AS IS" BASIS,
+     WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+     See the License for the specific language governing permissions and
+     limitations under the License.
+ -->
+
+<resources xmlns:android="http://schemas.android.com/apk/res/android"
+    xmlns:xliff="urn:oasis:names:tc:xliff:document:1.2">
+    <string name="no_upstream_notification_title" msgid="611650570559011140">"இணைப்பு முறைக்கு இணைய இணைப்பு இல்லை"</string>
+    <string name="no_upstream_notification_message" msgid="6508394877641864863">"சாதனங்களால் இணைய முடியவில்லை"</string>
+    <string name="no_upstream_notification_disable_button" msgid="7609346639290990508">"இணைப்பு முறையை ஆஃப் செய்"</string>
+    <string name="upstream_roaming_notification_title" msgid="6032901176124830787">"ஹாட்ஸ்பாட் அல்லது இணைப்பு முறை ஆன் செய்யப்பட்டுள்ளது"</string>
+    <string name="upstream_roaming_notification_message" msgid="7599056263326217523">"ரோமிங்கின்போது கூடுதல் கட்டணங்கள் விதிக்கப்படக்கூடும்"</string>
+</resources>
diff --git a/Tethering/res/values-mcc311-mnc480-te/strings.xml b/Tethering/res/values-mcc311-mnc480-te/strings.xml
new file mode 100644
index 0000000..9360297
--- /dev/null
+++ b/Tethering/res/values-mcc311-mnc480-te/strings.xml
@@ -0,0 +1,24 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!--  Copyright (C) 2020 The Android Open Source Project
+
+     Licensed under the Apache License, Version 2.0 (the "License");
+     you may not use this file except in compliance with the License.
+     You may obtain a copy of the License at
+
+          http://www.apache.org/licenses/LICENSE-2.0
+
+     Unless required by applicable law or agreed to in writing, software
+     distributed under the License is distributed on an "AS IS" BASIS,
+     WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+     See the License for the specific language governing permissions and
+     limitations under the License.
+ -->
+
+<resources xmlns:android="http://schemas.android.com/apk/res/android"
+    xmlns:xliff="urn:oasis:names:tc:xliff:document:1.2">
+    <string name="no_upstream_notification_title" msgid="611650570559011140">"టెథరింగ్ చేయడానికి ఇంటర్నెట్ కనెక్షన్ లేదు"</string>
+    <string name="no_upstream_notification_message" msgid="6508394877641864863">"పరికరాలు కనెక్ట్ అవ్వడం లేదు"</string>
+    <string name="no_upstream_notification_disable_button" msgid="7609346639290990508">"టెథరింగ్‌ను ఆఫ్ చేయండి"</string>
+    <string name="upstream_roaming_notification_title" msgid="6032901176124830787">"హాట్‌స్పాట్ లేదా టెథరింగ్ ఆన్‌లో ఉంది"</string>
+    <string name="upstream_roaming_notification_message" msgid="7599056263326217523">"రోమింగ్‌లో ఉన్నప్పుడు అదనపు ఛార్జీలు వర్తించవచ్చు"</string>
+</resources>
diff --git a/Tethering/res/values-mcc311-mnc480-th/strings.xml b/Tethering/res/values-mcc311-mnc480-th/strings.xml
new file mode 100644
index 0000000..9c4d7e0
--- /dev/null
+++ b/Tethering/res/values-mcc311-mnc480-th/strings.xml
@@ -0,0 +1,24 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!--  Copyright (C) 2020 The Android Open Source Project
+
+     Licensed under the Apache License, Version 2.0 (the "License");
+     you may not use this file except in compliance with the License.
+     You may obtain a copy of the License at
+
+          http://www.apache.org/licenses/LICENSE-2.0
+
+     Unless required by applicable law or agreed to in writing, software
+     distributed under the License is distributed on an "AS IS" BASIS,
+     WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+     See the License for the specific language governing permissions and
+     limitations under the License.
+ -->
+
+<resources xmlns:android="http://schemas.android.com/apk/res/android"
+    xmlns:xliff="urn:oasis:names:tc:xliff:document:1.2">
+    <string name="no_upstream_notification_title" msgid="611650570559011140">"การเชื่อมต่ออินเทอร์เน็ตผ่านมือถือไม่มีอินเทอร์เน็ต"</string>
+    <string name="no_upstream_notification_message" msgid="6508394877641864863">"อุปกรณ์เชื่อมต่อไม่ได้"</string>
+    <string name="no_upstream_notification_disable_button" msgid="7609346639290990508">"ปิดการเชื่อมต่ออินเทอร์เน็ตผ่านมือถือ"</string>
+    <string name="upstream_roaming_notification_title" msgid="6032901176124830787">"ฮอตสปอตหรือการเชื่อมต่ออินเทอร์เน็ตผ่านมือถือเปิดอยู่"</string>
+    <string name="upstream_roaming_notification_message" msgid="7599056263326217523">"อาจมีค่าใช้จ่ายเพิ่มเติมขณะโรมมิ่ง"</string>
+</resources>
diff --git a/Tethering/res/values-mcc311-mnc480-tl/strings.xml b/Tethering/res/values-mcc311-mnc480-tl/strings.xml
new file mode 100644
index 0000000..a7c78a5
--- /dev/null
+++ b/Tethering/res/values-mcc311-mnc480-tl/strings.xml
@@ -0,0 +1,24 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!--  Copyright (C) 2020 The Android Open Source Project
+
+     Licensed under the Apache License, Version 2.0 (the "License");
+     you may not use this file except in compliance with the License.
+     You may obtain a copy of the License at
+
+          http://www.apache.org/licenses/LICENSE-2.0
+
+     Unless required by applicable law or agreed to in writing, software
+     distributed under the License is distributed on an "AS IS" BASIS,
+     WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+     See the License for the specific language governing permissions and
+     limitations under the License.
+ -->
+
+<resources xmlns:android="http://schemas.android.com/apk/res/android"
+    xmlns:xliff="urn:oasis:names:tc:xliff:document:1.2">
+    <string name="no_upstream_notification_title" msgid="611650570559011140">"Walang internet ang pag-tether"</string>
+    <string name="no_upstream_notification_message" msgid="6508394877641864863">"Hindi makakonekta ang mga device"</string>
+    <string name="no_upstream_notification_disable_button" msgid="7609346639290990508">"I-off ang pag-tether"</string>
+    <string name="upstream_roaming_notification_title" msgid="6032901176124830787">"Naka-on ang Hotspot o pag-tether"</string>
+    <string name="upstream_roaming_notification_message" msgid="7599056263326217523">"Posibleng magkaroon ng mga karagdagang singil habang nagro-roam"</string>
+</resources>
diff --git a/Tethering/res/values-mcc311-mnc480-tr/strings.xml b/Tethering/res/values-mcc311-mnc480-tr/strings.xml
new file mode 100644
index 0000000..93da2c3
--- /dev/null
+++ b/Tethering/res/values-mcc311-mnc480-tr/strings.xml
@@ -0,0 +1,24 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!--  Copyright (C) 2020 The Android Open Source Project
+
+     Licensed under the Apache License, Version 2.0 (the "License");
+     you may not use this file except in compliance with the License.
+     You may obtain a copy of the License at
+
+          http://www.apache.org/licenses/LICENSE-2.0
+
+     Unless required by applicable law or agreed to in writing, software
+     distributed under the License is distributed on an "AS IS" BASIS,
+     WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+     See the License for the specific language governing permissions and
+     limitations under the License.
+ -->
+
+<resources xmlns:android="http://schemas.android.com/apk/res/android"
+    xmlns:xliff="urn:oasis:names:tc:xliff:document:1.2">
+    <string name="no_upstream_notification_title" msgid="611650570559011140">"Tethering\'in internet bağlantısı yok"</string>
+    <string name="no_upstream_notification_message" msgid="6508394877641864863">"Cihazlar bağlanamıyor"</string>
+    <string name="no_upstream_notification_disable_button" msgid="7609346639290990508">"Tethering\'i kapat"</string>
+    <string name="upstream_roaming_notification_title" msgid="6032901176124830787">"Hotspot veya tethering açık"</string>
+    <string name="upstream_roaming_notification_message" msgid="7599056263326217523">"Dolaşım sırasında ek ücretler uygulanabilir"</string>
+</resources>
diff --git a/Tethering/res/values-mcc311-mnc480-uk/strings.xml b/Tethering/res/values-mcc311-mnc480-uk/strings.xml
new file mode 100644
index 0000000..ee0dcd2
--- /dev/null
+++ b/Tethering/res/values-mcc311-mnc480-uk/strings.xml
@@ -0,0 +1,24 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!--  Copyright (C) 2020 The Android Open Source Project
+
+     Licensed under the Apache License, Version 2.0 (the "License");
+     you may not use this file except in compliance with the License.
+     You may obtain a copy of the License at
+
+          http://www.apache.org/licenses/LICENSE-2.0
+
+     Unless required by applicable law or agreed to in writing, software
+     distributed under the License is distributed on an "AS IS" BASIS,
+     WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+     See the License for the specific language governing permissions and
+     limitations under the License.
+ -->
+
+<resources xmlns:android="http://schemas.android.com/apk/res/android"
+    xmlns:xliff="urn:oasis:names:tc:xliff:document:1.2">
+    <string name="no_upstream_notification_title" msgid="611650570559011140">"Телефон, який використовується як модем, не підключений до Інтернету"</string>
+    <string name="no_upstream_notification_message" msgid="6508394877641864863">"Не вдається підключити пристрої"</string>
+    <string name="no_upstream_notification_disable_button" msgid="7609346639290990508">"Вимкнути використання телефона як модема"</string>
+    <string name="upstream_roaming_notification_title" msgid="6032901176124830787">"Увімкнено точку доступу або використання телефона як модема"</string>
+    <string name="upstream_roaming_notification_message" msgid="7599056263326217523">"У роумінгу може стягуватися додаткова плата"</string>
+</resources>
diff --git a/Tethering/res/values-mcc311-mnc480-ur/strings.xml b/Tethering/res/values-mcc311-mnc480-ur/strings.xml
new file mode 100644
index 0000000..41cd28e
--- /dev/null
+++ b/Tethering/res/values-mcc311-mnc480-ur/strings.xml
@@ -0,0 +1,24 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!--  Copyright (C) 2020 The Android Open Source Project
+
+     Licensed under the Apache License, Version 2.0 (the "License");
+     you may not use this file except in compliance with the License.
+     You may obtain a copy of the License at
+
+          http://www.apache.org/licenses/LICENSE-2.0
+
+     Unless required by applicable law or agreed to in writing, software
+     distributed under the License is distributed on an "AS IS" BASIS,
+     WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+     See the License for the specific language governing permissions and
+     limitations under the License.
+ -->
+
+<resources xmlns:android="http://schemas.android.com/apk/res/android"
+    xmlns:xliff="urn:oasis:names:tc:xliff:document:1.2">
+    <string name="no_upstream_notification_title" msgid="611650570559011140">"ٹیدرنگ میں انٹرنیٹ نہیں ہے"</string>
+    <string name="no_upstream_notification_message" msgid="6508394877641864863">"آلات منسلک نہیں ہو سکتے"</string>
+    <string name="no_upstream_notification_disable_button" msgid="7609346639290990508">"ٹیدرنگ آف کریں"</string>
+    <string name="upstream_roaming_notification_title" msgid="6032901176124830787">"ہاٹ اسپاٹ یا ٹیدرنگ آن ہے"</string>
+    <string name="upstream_roaming_notification_message" msgid="7599056263326217523">"رومنگ کے دوران اضافی چارجز لاگو ہو سکتے ہیں"</string>
+</resources>
diff --git a/Tethering/res/values-mcc311-mnc480-uz/strings.xml b/Tethering/res/values-mcc311-mnc480-uz/strings.xml
new file mode 100644
index 0000000..c847bc9
--- /dev/null
+++ b/Tethering/res/values-mcc311-mnc480-uz/strings.xml
@@ -0,0 +1,24 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!--  Copyright (C) 2020 The Android Open Source Project
+
+     Licensed under the Apache License, Version 2.0 (the "License");
+     you may not use this file except in compliance with the License.
+     You may obtain a copy of the License at
+
+          http://www.apache.org/licenses/LICENSE-2.0
+
+     Unless required by applicable law or agreed to in writing, software
+     distributed under the License is distributed on an "AS IS" BASIS,
+     WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+     See the License for the specific language governing permissions and
+     limitations under the License.
+ -->
+
+<resources xmlns:android="http://schemas.android.com/apk/res/android"
+    xmlns:xliff="urn:oasis:names:tc:xliff:document:1.2">
+    <string name="no_upstream_notification_title" msgid="611650570559011140">"Modem internetga ulanmagan"</string>
+    <string name="no_upstream_notification_message" msgid="6508394877641864863">"Qurilmalar ulanmadi"</string>
+    <string name="no_upstream_notification_disable_button" msgid="7609346639290990508">"Modem rejimini faolsizlantirish"</string>
+    <string name="upstream_roaming_notification_title" msgid="6032901176124830787">"Hotspot yoki modem rejimi yoniq"</string>
+    <string name="upstream_roaming_notification_message" msgid="7599056263326217523">"Rouming vaqtida qoʻshimcha haq olinishi mumkin"</string>
+</resources>
diff --git a/Tethering/res/values-mcc311-mnc480-vi/strings.xml b/Tethering/res/values-mcc311-mnc480-vi/strings.xml
new file mode 100644
index 0000000..a74326f
--- /dev/null
+++ b/Tethering/res/values-mcc311-mnc480-vi/strings.xml
@@ -0,0 +1,24 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!--  Copyright (C) 2020 The Android Open Source Project
+
+     Licensed under the Apache License, Version 2.0 (the "License");
+     you may not use this file except in compliance with the License.
+     You may obtain a copy of the License at
+
+          http://www.apache.org/licenses/LICENSE-2.0
+
+     Unless required by applicable law or agreed to in writing, software
+     distributed under the License is distributed on an "AS IS" BASIS,
+     WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+     See the License for the specific language governing permissions and
+     limitations under the License.
+ -->
+
+<resources xmlns:android="http://schemas.android.com/apk/res/android"
+    xmlns:xliff="urn:oasis:names:tc:xliff:document:1.2">
+    <string name="no_upstream_notification_title" msgid="611650570559011140">"Không có Internet để chia sẻ kết Internet"</string>
+    <string name="no_upstream_notification_message" msgid="6508394877641864863">"Các thiết bị không thể kết nối"</string>
+    <string name="no_upstream_notification_disable_button" msgid="7609346639290990508">"Tắt tính năng chia sẻ Internet"</string>
+    <string name="upstream_roaming_notification_title" msgid="6032901176124830787">"Điểm phát sóng hoặc tính năng chia sẻ Internet đang bật"</string>
+    <string name="upstream_roaming_notification_message" msgid="7599056263326217523">"Bạn có thể mất thêm phí dữ liệu khi chuyển vùng"</string>
+</resources>
diff --git a/Tethering/res/values-mcc311-mnc480-zh-rCN/strings.xml b/Tethering/res/values-mcc311-mnc480-zh-rCN/strings.xml
new file mode 100644
index 0000000..d737003
--- /dev/null
+++ b/Tethering/res/values-mcc311-mnc480-zh-rCN/strings.xml
@@ -0,0 +1,24 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!--  Copyright (C) 2020 The Android Open Source Project
+
+     Licensed under the Apache License, Version 2.0 (the "License");
+     you may not use this file except in compliance with the License.
+     You may obtain a copy of the License at
+
+          http://www.apache.org/licenses/LICENSE-2.0
+
+     Unless required by applicable law or agreed to in writing, software
+     distributed under the License is distributed on an "AS IS" BASIS,
+     WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+     See the License for the specific language governing permissions and
+     limitations under the License.
+ -->
+
+<resources xmlns:android="http://schemas.android.com/apk/res/android"
+    xmlns:xliff="urn:oasis:names:tc:xliff:document:1.2">
+    <string name="no_upstream_notification_title" msgid="611650570559011140">"共享网络未连接到互联网"</string>
+    <string name="no_upstream_notification_message" msgid="6508394877641864863">"设备无法连接"</string>
+    <string name="no_upstream_notification_disable_button" msgid="7609346639290990508">"关闭网络共享"</string>
+    <string name="upstream_roaming_notification_title" msgid="6032901176124830787">"热点或网络共享已开启"</string>
+    <string name="upstream_roaming_notification_message" msgid="7599056263326217523">"漫游时可能会产生额外的费用"</string>
+</resources>
diff --git a/Tethering/res/values-mcc311-mnc480-zh-rHK/strings.xml b/Tethering/res/values-mcc311-mnc480-zh-rHK/strings.xml
new file mode 100644
index 0000000..f378a9d
--- /dev/null
+++ b/Tethering/res/values-mcc311-mnc480-zh-rHK/strings.xml
@@ -0,0 +1,24 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!--  Copyright (C) 2020 The Android Open Source Project
+
+     Licensed under the Apache License, Version 2.0 (the "License");
+     you may not use this file except in compliance with the License.
+     You may obtain a copy of the License at
+
+          http://www.apache.org/licenses/LICENSE-2.0
+
+     Unless required by applicable law or agreed to in writing, software
+     distributed under the License is distributed on an "AS IS" BASIS,
+     WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+     See the License for the specific language governing permissions and
+     limitations under the License.
+ -->
+
+<resources xmlns:android="http://schemas.android.com/apk/res/android"
+    xmlns:xliff="urn:oasis:names:tc:xliff:document:1.2">
+    <string name="no_upstream_notification_title" msgid="611650570559011140">"無法透過網絡共享連線至互聯網"</string>
+    <string name="no_upstream_notification_message" msgid="6508394877641864863">"裝置無法連接"</string>
+    <string name="no_upstream_notification_disable_button" msgid="7609346639290990508">"關閉網絡共享"</string>
+    <string name="upstream_roaming_notification_title" msgid="6032901176124830787">"熱點或網絡共享已開啟"</string>
+    <string name="upstream_roaming_notification_message" msgid="7599056263326217523">"漫遊時可能需要支付額外費用"</string>
+</resources>
diff --git a/Tethering/res/values-mcc311-mnc480-zh-rTW/strings.xml b/Tethering/res/values-mcc311-mnc480-zh-rTW/strings.xml
new file mode 100644
index 0000000..cd653df
--- /dev/null
+++ b/Tethering/res/values-mcc311-mnc480-zh-rTW/strings.xml
@@ -0,0 +1,24 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!--  Copyright (C) 2020 The Android Open Source Project
+
+     Licensed under the Apache License, Version 2.0 (the "License");
+     you may not use this file except in compliance with the License.
+     You may obtain a copy of the License at
+
+          http://www.apache.org/licenses/LICENSE-2.0
+
+     Unless required by applicable law or agreed to in writing, software
+     distributed under the License is distributed on an "AS IS" BASIS,
+     WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+     See the License for the specific language governing permissions and
+     limitations under the License.
+ -->
+
+<resources xmlns:android="http://schemas.android.com/apk/res/android"
+    xmlns:xliff="urn:oasis:names:tc:xliff:document:1.2">
+    <string name="no_upstream_notification_title" msgid="611650570559011140">"無法透過網路共用連上網際網路"</string>
+    <string name="no_upstream_notification_message" msgid="6508394877641864863">"裝置無法連線"</string>
+    <string name="no_upstream_notification_disable_button" msgid="7609346639290990508">"關閉網路共用"</string>
+    <string name="upstream_roaming_notification_title" msgid="6032901176124830787">"無線基地台或網路共用已開啟"</string>
+    <string name="upstream_roaming_notification_message" msgid="7599056263326217523">"使用漫遊服務可能須支付額外費用"</string>
+</resources>
diff --git a/Tethering/res/values-mcc311-mnc480-zu/strings.xml b/Tethering/res/values-mcc311-mnc480-zu/strings.xml
new file mode 100644
index 0000000..32f6df5
--- /dev/null
+++ b/Tethering/res/values-mcc311-mnc480-zu/strings.xml
@@ -0,0 +1,24 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!--  Copyright (C) 2020 The Android Open Source Project
+
+     Licensed under the Apache License, Version 2.0 (the "License");
+     you may not use this file except in compliance with the License.
+     You may obtain a copy of the License at
+
+          http://www.apache.org/licenses/LICENSE-2.0
+
+     Unless required by applicable law or agreed to in writing, software
+     distributed under the License is distributed on an "AS IS" BASIS,
+     WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+     See the License for the specific language governing permissions and
+     limitations under the License.
+ -->
+
+<resources xmlns:android="http://schemas.android.com/apk/res/android"
+    xmlns:xliff="urn:oasis:names:tc:xliff:document:1.2">
+    <string name="no_upstream_notification_title" msgid="611650570559011140">"Ukusebenzisa ifoni njengemodemu akunayo i-inthanethi"</string>
+    <string name="no_upstream_notification_message" msgid="6508394877641864863">"Amadivayisi awakwazi ukuxhumeka"</string>
+    <string name="no_upstream_notification_disable_button" msgid="7609346639290990508">"Vala ukusebenzisa ifoni njengemodemu"</string>
+    <string name="upstream_roaming_notification_title" msgid="6032901176124830787">"I-hotspot noma ukusebenzisa ifoni njengemodemu kuvuliwe"</string>
+    <string name="upstream_roaming_notification_message" msgid="7599056263326217523">"Kungaba nezinkokhelo ezengeziwe uma uzula"</string>
+</resources>
diff --git a/Tethering/res/values-mcc311-mnc480/config.xml b/Tethering/res/values-mcc311-mnc480/config.xml
new file mode 100644
index 0000000..5c5be04
--- /dev/null
+++ b/Tethering/res/values-mcc311-mnc480/config.xml
@@ -0,0 +1,23 @@
+<?xml version="1.0" encoding="utf-8"?>
+<!-- Copyright (C) 2020 The Android Open Source Project
+
+     Licensed under the Apache License, Version 2.0 (the "License");
+     you may not use this file except in compliance with the License.
+     You may obtain a copy of the License at
+
+          http://www.apache.org/licenses/LICENSE-2.0
+
+     Unless required by applicable law or agreed to in writing, software
+     distributed under the License is distributed on an "AS IS" BASIS,
+     WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+     See the License for the specific language governing permissions and
+     limitations under the License.
+-->
+<resources>
+    <!-- Delay(millisecond) to show no upstream notification after there's no Backhaul. Set delay to
+         "0" for disable this feature. -->
+    <integer name="delay_to_show_no_upstream_after_no_backhaul">5000</integer>
+
+    <!-- Config for showing upstream roaming notification. -->
+    <bool name="config_upstream_roaming_notification">true</bool>
+</resources>
\ No newline at end of file
diff --git a/Tethering/res/values-mcc311-mnc480/strings.xml b/Tethering/res/values-mcc311-mnc480/strings.xml
new file mode 100644
index 0000000..ce9ff60
--- /dev/null
+++ b/Tethering/res/values-mcc311-mnc480/strings.xml
@@ -0,0 +1,28 @@
+<?xml version="1.0" encoding="utf-8"?>
+<!-- Copyright (C) 2020 The Android Open Source Project
+
+     Licensed under the Apache License, Version 2.0 (the "License");
+     you may not use this file except in compliance with the License.
+     You may obtain a copy of the License at
+
+          http://www.apache.org/licenses/LICENSE-2.0
+
+     Unless required by applicable law or agreed to in writing, software
+     distributed under the License is distributed on an "AS IS" BASIS,
+     WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+     See the License for the specific language governing permissions and
+     limitations under the License.
+-->
+<resources>
+    <!-- String for no upstream notification title [CHAR LIMIT=200] -->
+    <string name="no_upstream_notification_title">Tethering has no internet</string>
+    <!-- String for no upstream notification title [CHAR LIMIT=200] -->
+    <string name="no_upstream_notification_message">Devices can\u2019t connect</string>
+    <!-- String for no upstream notification disable button [CHAR LIMIT=200] -->
+    <string name="no_upstream_notification_disable_button">Turn off tethering</string>
+
+    <!-- String for cellular roaming notification title [CHAR LIMIT=200] -->
+    <string name="upstream_roaming_notification_title">Hotspot or tethering is on</string>
+    <!-- String for cellular roaming notification message [CHAR LIMIT=500] -->
+    <string name="upstream_roaming_notification_message">Additional charges may apply while roaming</string>
+</resources>
diff --git a/Tethering/res/values-mk/strings.xml b/Tethering/res/values-mk/strings.xml
new file mode 100644
index 0000000..9ad9b9a
--- /dev/null
+++ b/Tethering/res/values-mk/strings.xml
@@ -0,0 +1,29 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!--  Copyright (C) 2020 The Android Open Source Project
+
+     Licensed under the Apache License, Version 2.0 (the "License");
+     you may not use this file except in compliance with the License.
+     You may obtain a copy of the License at
+
+          http://www.apache.org/licenses/LICENSE-2.0
+
+     Unless required by applicable law or agreed to in writing, software
+     distributed under the License is distributed on an "AS IS" BASIS,
+     WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+     See the License for the specific language governing permissions and
+     limitations under the License.
+ -->
+
+<resources xmlns:android="http://schemas.android.com/apk/res/android"
+    xmlns:xliff="urn:oasis:names:tc:xliff:document:1.2">
+    <string name="tethered_notification_title" msgid="6426563586025792944">"Активно е врзување или точка на пристап"</string>
+    <string name="tethered_notification_message" msgid="64800879503420696">"Допрете за поставување."</string>
+    <string name="disable_tether_notification_title" msgid="3004509127903564191">"Врзувањето е оневозможено"</string>
+    <string name="disable_tether_notification_message" msgid="6717523799293901476">"Контактирајте со администраторот за детали"</string>
+    <string name="notification_channel_tethering_status" msgid="2663463891530932727">"Статус на точката на пристап и врзувањето"</string>
+    <string name="no_upstream_notification_title" msgid="1204601824631788482"></string>
+    <string name="no_upstream_notification_message" msgid="8586582938243032621"></string>
+    <string name="no_upstream_notification_disable_button" msgid="8800919436924640822"></string>
+    <string name="upstream_roaming_notification_title" msgid="4772373823198997030"></string>
+    <string name="upstream_roaming_notification_message" msgid="3985577843181551650"></string>
+</resources>
diff --git a/Tethering/res/values-ml/strings.xml b/Tethering/res/values-ml/strings.xml
new file mode 100644
index 0000000..9db79ce
--- /dev/null
+++ b/Tethering/res/values-ml/strings.xml
@@ -0,0 +1,29 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!--  Copyright (C) 2020 The Android Open Source Project
+
+     Licensed under the Apache License, Version 2.0 (the "License");
+     you may not use this file except in compliance with the License.
+     You may obtain a copy of the License at
+
+          http://www.apache.org/licenses/LICENSE-2.0
+
+     Unless required by applicable law or agreed to in writing, software
+     distributed under the License is distributed on an "AS IS" BASIS,
+     WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+     See the License for the specific language governing permissions and
+     limitations under the License.
+ -->
+
+<resources xmlns:android="http://schemas.android.com/apk/res/android"
+    xmlns:xliff="urn:oasis:names:tc:xliff:document:1.2">
+    <string name="tethered_notification_title" msgid="6426563586025792944">"ടെതറിംഗ് അല്ലെങ്കിൽ ഹോട്ട്സ്‌പോട്ട് സജീവമാണ്"</string>
+    <string name="tethered_notification_message" msgid="64800879503420696">"സജ്ജീകരിക്കാൻ ടാപ്പ് ചെയ്യുക."</string>
+    <string name="disable_tether_notification_title" msgid="3004509127903564191">"ടെതറിംഗ് പ്രവർത്തനരഹിതമാക്കിയിരിക്കുന്നു"</string>
+    <string name="disable_tether_notification_message" msgid="6717523799293901476">"വിശദാംശങ്ങൾക്ക് നിങ്ങളുടെ അഡ്മിനെ ബന്ധപ്പെടുക"</string>
+    <string name="notification_channel_tethering_status" msgid="2663463891530932727">"ഹോട്ട്‌സ്പോട്ടിന്റെയും ടെതറിംഗിന്റെയും നില"</string>
+    <string name="no_upstream_notification_title" msgid="1204601824631788482"></string>
+    <string name="no_upstream_notification_message" msgid="8586582938243032621"></string>
+    <string name="no_upstream_notification_disable_button" msgid="8800919436924640822"></string>
+    <string name="upstream_roaming_notification_title" msgid="4772373823198997030"></string>
+    <string name="upstream_roaming_notification_message" msgid="3985577843181551650"></string>
+</resources>
diff --git a/Tethering/res/values-mn/strings.xml b/Tethering/res/values-mn/strings.xml
new file mode 100644
index 0000000..42d1edb
--- /dev/null
+++ b/Tethering/res/values-mn/strings.xml
@@ -0,0 +1,29 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!--  Copyright (C) 2020 The Android Open Source Project
+
+     Licensed under the Apache License, Version 2.0 (the "License");
+     you may not use this file except in compliance with the License.
+     You may obtain a copy of the License at
+
+          http://www.apache.org/licenses/LICENSE-2.0
+
+     Unless required by applicable law or agreed to in writing, software
+     distributed under the License is distributed on an "AS IS" BASIS,
+     WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+     See the License for the specific language governing permissions and
+     limitations under the License.
+ -->
+
+<resources xmlns:android="http://schemas.android.com/apk/res/android"
+    xmlns:xliff="urn:oasis:names:tc:xliff:document:1.2">
+    <string name="tethered_notification_title" msgid="6426563586025792944">"Модем болгох эсвэл сүлжээний цэг идэвхтэй байна"</string>
+    <string name="tethered_notification_message" msgid="64800879503420696">"Тохируулахын тулд товшино уу."</string>
+    <string name="disable_tether_notification_title" msgid="3004509127903564191">"Модем болгохыг идэвхгүй болгосон"</string>
+    <string name="disable_tether_notification_message" msgid="6717523799293901476">"Дэлгэрэнгүй мэдээлэл авахын тулд админтайгаа холбогдоно уу"</string>
+    <string name="notification_channel_tethering_status" msgid="2663463891530932727">"Сүлжээний цэг болон модем болгох төлөв"</string>
+    <string name="no_upstream_notification_title" msgid="1204601824631788482"></string>
+    <string name="no_upstream_notification_message" msgid="8586582938243032621"></string>
+    <string name="no_upstream_notification_disable_button" msgid="8800919436924640822"></string>
+    <string name="upstream_roaming_notification_title" msgid="4772373823198997030"></string>
+    <string name="upstream_roaming_notification_message" msgid="3985577843181551650"></string>
+</resources>
diff --git a/Tethering/res/values-mr/strings.xml b/Tethering/res/values-mr/strings.xml
new file mode 100644
index 0000000..13995b6
--- /dev/null
+++ b/Tethering/res/values-mr/strings.xml
@@ -0,0 +1,29 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!--  Copyright (C) 2020 The Android Open Source Project
+
+     Licensed under the Apache License, Version 2.0 (the "License");
+     you may not use this file except in compliance with the License.
+     You may obtain a copy of the License at
+
+          http://www.apache.org/licenses/LICENSE-2.0
+
+     Unless required by applicable law or agreed to in writing, software
+     distributed under the License is distributed on an "AS IS" BASIS,
+     WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+     See the License for the specific language governing permissions and
+     limitations under the License.
+ -->
+
+<resources xmlns:android="http://schemas.android.com/apk/res/android"
+    xmlns:xliff="urn:oasis:names:tc:xliff:document:1.2">
+    <string name="tethered_notification_title" msgid="6426563586025792944">"टेदरिंग किंवा हॉटस्पॉट अ‍ॅक्टिव्ह आहे"</string>
+    <string name="tethered_notification_message" msgid="64800879503420696">"सेट करण्यासाठी टॅप करा."</string>
+    <string name="disable_tether_notification_title" msgid="3004509127903564191">"टेदरिंग बंद केले आहे"</string>
+    <string name="disable_tether_notification_message" msgid="6717523799293901476">"तपशीलांसाठी तुमच्या ॲडमिनशी संपर्क साधा"</string>
+    <string name="notification_channel_tethering_status" msgid="2663463891530932727">"हॉटस्पॉट आणि टेदरिंगची स्थिती"</string>
+    <string name="no_upstream_notification_title" msgid="1204601824631788482"></string>
+    <string name="no_upstream_notification_message" msgid="8586582938243032621"></string>
+    <string name="no_upstream_notification_disable_button" msgid="8800919436924640822"></string>
+    <string name="upstream_roaming_notification_title" msgid="4772373823198997030"></string>
+    <string name="upstream_roaming_notification_message" msgid="3985577843181551650"></string>
+</resources>
diff --git a/Tethering/res/values-ms/strings.xml b/Tethering/res/values-ms/strings.xml
new file mode 100644
index 0000000..d6a67f3
--- /dev/null
+++ b/Tethering/res/values-ms/strings.xml
@@ -0,0 +1,29 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!--  Copyright (C) 2020 The Android Open Source Project
+
+     Licensed under the Apache License, Version 2.0 (the "License");
+     you may not use this file except in compliance with the License.
+     You may obtain a copy of the License at
+
+          http://www.apache.org/licenses/LICENSE-2.0
+
+     Unless required by applicable law or agreed to in writing, software
+     distributed under the License is distributed on an "AS IS" BASIS,
+     WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+     See the License for the specific language governing permissions and
+     limitations under the License.
+ -->
+
+<resources xmlns:android="http://schemas.android.com/apk/res/android"
+    xmlns:xliff="urn:oasis:names:tc:xliff:document:1.2">
+    <string name="tethered_notification_title" msgid="6426563586025792944">"Penambatan atau tempat liputan aktif"</string>
+    <string name="tethered_notification_message" msgid="64800879503420696">"Ketik untuk membuat persediaan."</string>
+    <string name="disable_tether_notification_title" msgid="3004509127903564191">"Penambatan dilumpuhkan"</string>
+    <string name="disable_tether_notification_message" msgid="6717523799293901476">"Hubungi pentadbir anda untuk mendapatkan maklumat lanjut"</string>
+    <string name="notification_channel_tethering_status" msgid="2663463891530932727">"Status tempat liputan &amp; penambatan"</string>
+    <string name="no_upstream_notification_title" msgid="1204601824631788482"></string>
+    <string name="no_upstream_notification_message" msgid="8586582938243032621"></string>
+    <string name="no_upstream_notification_disable_button" msgid="8800919436924640822"></string>
+    <string name="upstream_roaming_notification_title" msgid="4772373823198997030"></string>
+    <string name="upstream_roaming_notification_message" msgid="3985577843181551650"></string>
+</resources>
diff --git a/Tethering/res/values-my/strings.xml b/Tethering/res/values-my/strings.xml
new file mode 100644
index 0000000..49f6b88
--- /dev/null
+++ b/Tethering/res/values-my/strings.xml
@@ -0,0 +1,29 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!--  Copyright (C) 2020 The Android Open Source Project
+
+     Licensed under the Apache License, Version 2.0 (the "License");
+     you may not use this file except in compliance with the License.
+     You may obtain a copy of the License at
+
+          http://www.apache.org/licenses/LICENSE-2.0
+
+     Unless required by applicable law or agreed to in writing, software
+     distributed under the License is distributed on an "AS IS" BASIS,
+     WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+     See the License for the specific language governing permissions and
+     limitations under the License.
+ -->
+
+<resources xmlns:android="http://schemas.android.com/apk/res/android"
+    xmlns:xliff="urn:oasis:names:tc:xliff:document:1.2">
+    <string name="tethered_notification_title" msgid="6426563586025792944">"မိုဘိုင်းဖုန်းသုံး ချိတ်ဆက်မျှဝေခြင်း သို့မဟုတ် ဟော့စပေါ့ ဖွင့်ထားသည်"</string>
+    <string name="tethered_notification_message" msgid="64800879503420696">"စနစ်ထည့်သွင်းရန် တို့ပါ။"</string>
+    <string name="disable_tether_notification_title" msgid="3004509127903564191">"မိုဘိုင်းဖုန်းသုံး ချိတ်ဆက်မျှဝေခြင်းကို ပိတ်ထားသည်"</string>
+    <string name="disable_tether_notification_message" msgid="6717523799293901476">"အသေးစိတ်အတွက် သင့်စီမံခန့်ခွဲသူကို ဆက်သွယ်ပါ"</string>
+    <string name="notification_channel_tethering_status" msgid="2663463891530932727">"ဟော့စပေါ့နှင့် မိုဘိုင်းဖုန်းသုံး ချိတ်ဆက်မျှဝေခြင်း အခြေအနေ"</string>
+    <string name="no_upstream_notification_title" msgid="1204601824631788482"></string>
+    <string name="no_upstream_notification_message" msgid="8586582938243032621"></string>
+    <string name="no_upstream_notification_disable_button" msgid="8800919436924640822"></string>
+    <string name="upstream_roaming_notification_title" msgid="4772373823198997030"></string>
+    <string name="upstream_roaming_notification_message" msgid="3985577843181551650"></string>
+</resources>
diff --git a/Tethering/res/values-nb/strings.xml b/Tethering/res/values-nb/strings.xml
new file mode 100644
index 0000000..9594e0a
--- /dev/null
+++ b/Tethering/res/values-nb/strings.xml
@@ -0,0 +1,29 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!--  Copyright (C) 2020 The Android Open Source Project
+
+     Licensed under the Apache License, Version 2.0 (the "License");
+     you may not use this file except in compliance with the License.
+     You may obtain a copy of the License at
+
+          http://www.apache.org/licenses/LICENSE-2.0
+
+     Unless required by applicable law or agreed to in writing, software
+     distributed under the License is distributed on an "AS IS" BASIS,
+     WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+     See the License for the specific language governing permissions and
+     limitations under the License.
+ -->
+
+<resources xmlns:android="http://schemas.android.com/apk/res/android"
+    xmlns:xliff="urn:oasis:names:tc:xliff:document:1.2">
+    <string name="tethered_notification_title" msgid="6426563586025792944">"Internettdeling eller Wi-Fi-sone er aktiv"</string>
+    <string name="tethered_notification_message" msgid="64800879503420696">"Trykk for å konfigurere."</string>
+    <string name="disable_tether_notification_title" msgid="3004509127903564191">"Internettdeling er slått av"</string>
+    <string name="disable_tether_notification_message" msgid="6717523799293901476">"Ta kontakt med administratoren din for å få mer informasjon"</string>
+    <string name="notification_channel_tethering_status" msgid="2663463891530932727">"Status for Wi-Fi-sone og internettdeling"</string>
+    <string name="no_upstream_notification_title" msgid="1204601824631788482"></string>
+    <string name="no_upstream_notification_message" msgid="8586582938243032621"></string>
+    <string name="no_upstream_notification_disable_button" msgid="8800919436924640822"></string>
+    <string name="upstream_roaming_notification_title" msgid="4772373823198997030"></string>
+    <string name="upstream_roaming_notification_message" msgid="3985577843181551650"></string>
+</resources>
diff --git a/Tethering/res/values-ne/strings.xml b/Tethering/res/values-ne/strings.xml
new file mode 100644
index 0000000..72ae3a8
--- /dev/null
+++ b/Tethering/res/values-ne/strings.xml
@@ -0,0 +1,29 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!--  Copyright (C) 2020 The Android Open Source Project
+
+     Licensed under the Apache License, Version 2.0 (the "License");
+     you may not use this file except in compliance with the License.
+     You may obtain a copy of the License at
+
+          http://www.apache.org/licenses/LICENSE-2.0
+
+     Unless required by applicable law or agreed to in writing, software
+     distributed under the License is distributed on an "AS IS" BASIS,
+     WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+     See the License for the specific language governing permissions and
+     limitations under the License.
+ -->
+
+<resources xmlns:android="http://schemas.android.com/apk/res/android"
+    xmlns:xliff="urn:oasis:names:tc:xliff:document:1.2">
+    <string name="tethered_notification_title" msgid="6426563586025792944">"टेदरिङ वा हटस्पट सक्रिय छ"</string>
+    <string name="tethered_notification_message" msgid="64800879503420696">"सेटअप गर्न ट्याप गर्नुहोस्।"</string>
+    <string name="disable_tether_notification_title" msgid="3004509127903564191">"टेदरिङ सुविधा असक्षम पारिएको छ"</string>
+    <string name="disable_tether_notification_message" msgid="6717523799293901476">"विवरणहरूका लागि आफ्ना प्रशासकलाई सम्पर्क गर्नुहोस्"</string>
+    <string name="notification_channel_tethering_status" msgid="2663463891530932727">"हटस्पट तथा टेदरिङको स्थिति"</string>
+    <string name="no_upstream_notification_title" msgid="1204601824631788482"></string>
+    <string name="no_upstream_notification_message" msgid="8586582938243032621"></string>
+    <string name="no_upstream_notification_disable_button" msgid="8800919436924640822"></string>
+    <string name="upstream_roaming_notification_title" msgid="4772373823198997030"></string>
+    <string name="upstream_roaming_notification_message" msgid="3985577843181551650"></string>
+</resources>
diff --git a/Tethering/res/values-nl/strings.xml b/Tethering/res/values-nl/strings.xml
new file mode 100644
index 0000000..18b2bbf
--- /dev/null
+++ b/Tethering/res/values-nl/strings.xml
@@ -0,0 +1,29 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!--  Copyright (C) 2020 The Android Open Source Project
+
+     Licensed under the Apache License, Version 2.0 (the "License");
+     you may not use this file except in compliance with the License.
+     You may obtain a copy of the License at
+
+          http://www.apache.org/licenses/LICENSE-2.0
+
+     Unless required by applicable law or agreed to in writing, software
+     distributed under the License is distributed on an "AS IS" BASIS,
+     WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+     See the License for the specific language governing permissions and
+     limitations under the License.
+ -->
+
+<resources xmlns:android="http://schemas.android.com/apk/res/android"
+    xmlns:xliff="urn:oasis:names:tc:xliff:document:1.2">
+    <string name="tethered_notification_title" msgid="6426563586025792944">"Tethering of hotspot actief"</string>
+    <string name="tethered_notification_message" msgid="64800879503420696">"Tik om in te stellen."</string>
+    <string name="disable_tether_notification_title" msgid="3004509127903564191">"Tethering is uitgeschakeld"</string>
+    <string name="disable_tether_notification_message" msgid="6717523799293901476">"Neem contact op met je beheerder voor meer informatie"</string>
+    <string name="notification_channel_tethering_status" msgid="2663463891530932727">"Status van hotspot en tethering"</string>
+    <string name="no_upstream_notification_title" msgid="1204601824631788482"></string>
+    <string name="no_upstream_notification_message" msgid="8586582938243032621"></string>
+    <string name="no_upstream_notification_disable_button" msgid="8800919436924640822"></string>
+    <string name="upstream_roaming_notification_title" msgid="4772373823198997030"></string>
+    <string name="upstream_roaming_notification_message" msgid="3985577843181551650"></string>
+</resources>
diff --git a/Tethering/res/values-or/strings.xml b/Tethering/res/values-or/strings.xml
new file mode 100644
index 0000000..a15a6db
--- /dev/null
+++ b/Tethering/res/values-or/strings.xml
@@ -0,0 +1,29 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!--  Copyright (C) 2020 The Android Open Source Project
+
+     Licensed under the Apache License, Version 2.0 (the "License");
+     you may not use this file except in compliance with the License.
+     You may obtain a copy of the License at
+
+          http://www.apache.org/licenses/LICENSE-2.0
+
+     Unless required by applicable law or agreed to in writing, software
+     distributed under the License is distributed on an "AS IS" BASIS,
+     WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+     See the License for the specific language governing permissions and
+     limitations under the License.
+ -->
+
+<resources xmlns:android="http://schemas.android.com/apk/res/android"
+    xmlns:xliff="urn:oasis:names:tc:xliff:document:1.2">
+    <string name="tethered_notification_title" msgid="6426563586025792944">"ଟିଥେରିଂ କିମ୍ୱା ହଟସ୍ପଟ୍ ସକ୍ରିୟ ଅଛି"</string>
+    <string name="tethered_notification_message" msgid="64800879503420696">"ସେଟ୍ ଅପ୍ କରିବାକୁ ଟାପ୍ କରନ୍ତୁ।"</string>
+    <string name="disable_tether_notification_title" msgid="3004509127903564191">"ଟିଥେରିଂ ଅକ୍ଷମ କରାଯାଇଛି"</string>
+    <string name="disable_tether_notification_message" msgid="6717523799293901476">"ବିବରଣୀଗୁଡ଼ିକ ପାଇଁ ଆପଣଙ୍କ ଆଡମିନଙ୍କ ସହ ଯୋଗାଯୋଗ କରନ୍ତୁ"</string>
+    <string name="notification_channel_tethering_status" msgid="2663463891530932727">"ହଟସ୍ପଟ୍ ଓ ଟିଥେରିଂ ସ୍ଥିତି"</string>
+    <string name="no_upstream_notification_title" msgid="1204601824631788482"></string>
+    <string name="no_upstream_notification_message" msgid="8586582938243032621"></string>
+    <string name="no_upstream_notification_disable_button" msgid="8800919436924640822"></string>
+    <string name="upstream_roaming_notification_title" msgid="4772373823198997030"></string>
+    <string name="upstream_roaming_notification_message" msgid="3985577843181551650"></string>
+</resources>
diff --git a/Tethering/res/values-pa/strings.xml b/Tethering/res/values-pa/strings.xml
new file mode 100644
index 0000000..a8235e4
--- /dev/null
+++ b/Tethering/res/values-pa/strings.xml
@@ -0,0 +1,29 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!--  Copyright (C) 2020 The Android Open Source Project
+
+     Licensed under the Apache License, Version 2.0 (the "License");
+     you may not use this file except in compliance with the License.
+     You may obtain a copy of the License at
+
+          http://www.apache.org/licenses/LICENSE-2.0
+
+     Unless required by applicable law or agreed to in writing, software
+     distributed under the License is distributed on an "AS IS" BASIS,
+     WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+     See the License for the specific language governing permissions and
+     limitations under the License.
+ -->
+
+<resources xmlns:android="http://schemas.android.com/apk/res/android"
+    xmlns:xliff="urn:oasis:names:tc:xliff:document:1.2">
+    <string name="tethered_notification_title" msgid="6426563586025792944">"ਟੈਦਰਿੰਗ ਜਾਂ ਹੌਟਸਪੌਟ ਕਿਰਿਆਸ਼ੀਲ"</string>
+    <string name="tethered_notification_message" msgid="64800879503420696">"ਸੈੱਟਅੱਪ ਕਰਨ ਲਈ ਟੈਪ ਕਰੋ।"</string>
+    <string name="disable_tether_notification_title" msgid="3004509127903564191">"ਟੈਦਰਿੰਗ ਨੂੰ ਬੰਦ ਕੀਤਾ ਗਿਆ ਹੈ"</string>
+    <string name="disable_tether_notification_message" msgid="6717523799293901476">"ਵੇਰਵਿਆਂ ਲਈ ਆਪਣੇ ਪ੍ਰਸ਼ਾਸਕ ਨਾਲ ਸੰਪਰਕ ਕਰੋ"</string>
+    <string name="notification_channel_tethering_status" msgid="2663463891530932727">"ਹੌਟਸਪੌਟ ਅਤੇ ਟੈਦਰਿੰਗ ਦੀ ਸਥਿਤੀ"</string>
+    <string name="no_upstream_notification_title" msgid="1204601824631788482"></string>
+    <string name="no_upstream_notification_message" msgid="8586582938243032621"></string>
+    <string name="no_upstream_notification_disable_button" msgid="8800919436924640822"></string>
+    <string name="upstream_roaming_notification_title" msgid="4772373823198997030"></string>
+    <string name="upstream_roaming_notification_message" msgid="3985577843181551650"></string>
+</resources>
diff --git a/Tethering/res/values-pl/strings.xml b/Tethering/res/values-pl/strings.xml
new file mode 100644
index 0000000..ccb017d
--- /dev/null
+++ b/Tethering/res/values-pl/strings.xml
@@ -0,0 +1,29 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!--  Copyright (C) 2020 The Android Open Source Project
+
+     Licensed under the Apache License, Version 2.0 (the "License");
+     you may not use this file except in compliance with the License.
+     You may obtain a copy of the License at
+
+          http://www.apache.org/licenses/LICENSE-2.0
+
+     Unless required by applicable law or agreed to in writing, software
+     distributed under the License is distributed on an "AS IS" BASIS,
+     WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+     See the License for the specific language governing permissions and
+     limitations under the License.
+ -->
+
+<resources xmlns:android="http://schemas.android.com/apk/res/android"
+    xmlns:xliff="urn:oasis:names:tc:xliff:document:1.2">
+    <string name="tethered_notification_title" msgid="6426563586025792944">"Aktywny tethering lub punkt dostępu"</string>
+    <string name="tethered_notification_message" msgid="64800879503420696">"Kliknij, by skonfigurować"</string>
+    <string name="disable_tether_notification_title" msgid="3004509127903564191">"Tethering został wyłączony"</string>
+    <string name="disable_tether_notification_message" msgid="6717523799293901476">"Aby uzyskać szczegółowe informacje, skontaktuj się z administratorem"</string>
+    <string name="notification_channel_tethering_status" msgid="2663463891530932727">"Hotspot i tethering – stan"</string>
+    <string name="no_upstream_notification_title" msgid="1204601824631788482"></string>
+    <string name="no_upstream_notification_message" msgid="8586582938243032621"></string>
+    <string name="no_upstream_notification_disable_button" msgid="8800919436924640822"></string>
+    <string name="upstream_roaming_notification_title" msgid="4772373823198997030"></string>
+    <string name="upstream_roaming_notification_message" msgid="3985577843181551650"></string>
+</resources>
diff --git a/Tethering/res/values-pt-rBR/strings.xml b/Tethering/res/values-pt-rBR/strings.xml
new file mode 100644
index 0000000..a0a4745
--- /dev/null
+++ b/Tethering/res/values-pt-rBR/strings.xml
@@ -0,0 +1,29 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!--  Copyright (C) 2020 The Android Open Source Project
+
+     Licensed under the Apache License, Version 2.0 (the "License");
+     you may not use this file except in compliance with the License.
+     You may obtain a copy of the License at
+
+          http://www.apache.org/licenses/LICENSE-2.0
+
+     Unless required by applicable law or agreed to in writing, software
+     distributed under the License is distributed on an "AS IS" BASIS,
+     WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+     See the License for the specific language governing permissions and
+     limitations under the License.
+ -->
+
+<resources xmlns:android="http://schemas.android.com/apk/res/android"
+    xmlns:xliff="urn:oasis:names:tc:xliff:document:1.2">
+    <string name="tethered_notification_title" msgid="6426563586025792944">"Ponto de acesso ou tethering ativo"</string>
+    <string name="tethered_notification_message" msgid="64800879503420696">"Toque para configurar."</string>
+    <string name="disable_tether_notification_title" msgid="3004509127903564191">"Tethering desativado"</string>
+    <string name="disable_tether_notification_message" msgid="6717523799293901476">"Fale com seu administrador para saber detalhes"</string>
+    <string name="notification_channel_tethering_status" msgid="2663463891530932727">"Status de ponto de acesso e tethering"</string>
+    <string name="no_upstream_notification_title" msgid="1204601824631788482"></string>
+    <string name="no_upstream_notification_message" msgid="8586582938243032621"></string>
+    <string name="no_upstream_notification_disable_button" msgid="8800919436924640822"></string>
+    <string name="upstream_roaming_notification_title" msgid="4772373823198997030"></string>
+    <string name="upstream_roaming_notification_message" msgid="3985577843181551650"></string>
+</resources>
diff --git a/Tethering/res/values-pt-rPT/strings.xml b/Tethering/res/values-pt-rPT/strings.xml
new file mode 100644
index 0000000..e3f03fc
--- /dev/null
+++ b/Tethering/res/values-pt-rPT/strings.xml
@@ -0,0 +1,29 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!--  Copyright (C) 2020 The Android Open Source Project
+
+     Licensed under the Apache License, Version 2.0 (the "License");
+     you may not use this file except in compliance with the License.
+     You may obtain a copy of the License at
+
+          http://www.apache.org/licenses/LICENSE-2.0
+
+     Unless required by applicable law or agreed to in writing, software
+     distributed under the License is distributed on an "AS IS" BASIS,
+     WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+     See the License for the specific language governing permissions and
+     limitations under the License.
+ -->
+
+<resources xmlns:android="http://schemas.android.com/apk/res/android"
+    xmlns:xliff="urn:oasis:names:tc:xliff:document:1.2">
+    <string name="tethered_notification_title" msgid="6426563586025792944">"Ligação (à Internet) via telemóvel ou zona Wi-Fi ativas"</string>
+    <string name="tethered_notification_message" msgid="64800879503420696">"Toque para configurar."</string>
+    <string name="disable_tether_notification_title" msgid="3004509127903564191">"A ligação (à Internet) via telemóvel está desativada."</string>
+    <string name="disable_tether_notification_message" msgid="6717523799293901476">"Contacte o administrador para obter detalhes."</string>
+    <string name="notification_channel_tethering_status" msgid="2663463891530932727">"Estado da zona Wi-Fi e da ligação (à Internet) via telemóvel"</string>
+    <string name="no_upstream_notification_title" msgid="1204601824631788482"></string>
+    <string name="no_upstream_notification_message" msgid="8586582938243032621"></string>
+    <string name="no_upstream_notification_disable_button" msgid="8800919436924640822"></string>
+    <string name="upstream_roaming_notification_title" msgid="4772373823198997030"></string>
+    <string name="upstream_roaming_notification_message" msgid="3985577843181551650"></string>
+</resources>
diff --git a/Tethering/res/values-pt/strings.xml b/Tethering/res/values-pt/strings.xml
new file mode 100644
index 0000000..a0a4745
--- /dev/null
+++ b/Tethering/res/values-pt/strings.xml
@@ -0,0 +1,29 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!--  Copyright (C) 2020 The Android Open Source Project
+
+     Licensed under the Apache License, Version 2.0 (the "License");
+     you may not use this file except in compliance with the License.
+     You may obtain a copy of the License at
+
+          http://www.apache.org/licenses/LICENSE-2.0
+
+     Unless required by applicable law or agreed to in writing, software
+     distributed under the License is distributed on an "AS IS" BASIS,
+     WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+     See the License for the specific language governing permissions and
+     limitations under the License.
+ -->
+
+<resources xmlns:android="http://schemas.android.com/apk/res/android"
+    xmlns:xliff="urn:oasis:names:tc:xliff:document:1.2">
+    <string name="tethered_notification_title" msgid="6426563586025792944">"Ponto de acesso ou tethering ativo"</string>
+    <string name="tethered_notification_message" msgid="64800879503420696">"Toque para configurar."</string>
+    <string name="disable_tether_notification_title" msgid="3004509127903564191">"Tethering desativado"</string>
+    <string name="disable_tether_notification_message" msgid="6717523799293901476">"Fale com seu administrador para saber detalhes"</string>
+    <string name="notification_channel_tethering_status" msgid="2663463891530932727">"Status de ponto de acesso e tethering"</string>
+    <string name="no_upstream_notification_title" msgid="1204601824631788482"></string>
+    <string name="no_upstream_notification_message" msgid="8586582938243032621"></string>
+    <string name="no_upstream_notification_disable_button" msgid="8800919436924640822"></string>
+    <string name="upstream_roaming_notification_title" msgid="4772373823198997030"></string>
+    <string name="upstream_roaming_notification_message" msgid="3985577843181551650"></string>
+</resources>
diff --git a/Tethering/res/values-ro/strings.xml b/Tethering/res/values-ro/strings.xml
new file mode 100644
index 0000000..5706a4a
--- /dev/null
+++ b/Tethering/res/values-ro/strings.xml
@@ -0,0 +1,29 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!--  Copyright (C) 2020 The Android Open Source Project
+
+     Licensed under the Apache License, Version 2.0 (the "License");
+     you may not use this file except in compliance with the License.
+     You may obtain a copy of the License at
+
+          http://www.apache.org/licenses/LICENSE-2.0
+
+     Unless required by applicable law or agreed to in writing, software
+     distributed under the License is distributed on an "AS IS" BASIS,
+     WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+     See the License for the specific language governing permissions and
+     limitations under the License.
+ -->
+
+<resources xmlns:android="http://schemas.android.com/apk/res/android"
+    xmlns:xliff="urn:oasis:names:tc:xliff:document:1.2">
+    <string name="tethered_notification_title" msgid="6426563586025792944">"Tethering sau hotspot activ"</string>
+    <string name="tethered_notification_message" msgid="64800879503420696">"Atingeți ca să configurați."</string>
+    <string name="disable_tether_notification_title" msgid="3004509127903564191">"Tetheringul este dezactivat"</string>
+    <string name="disable_tether_notification_message" msgid="6717523799293901476">"Contactați administratorul pentru detalii"</string>
+    <string name="notification_channel_tethering_status" msgid="2663463891530932727">"Starea hotspotului și a tetheringului"</string>
+    <string name="no_upstream_notification_title" msgid="1204601824631788482"></string>
+    <string name="no_upstream_notification_message" msgid="8586582938243032621"></string>
+    <string name="no_upstream_notification_disable_button" msgid="8800919436924640822"></string>
+    <string name="upstream_roaming_notification_title" msgid="4772373823198997030"></string>
+    <string name="upstream_roaming_notification_message" msgid="3985577843181551650"></string>
+</resources>
diff --git a/Tethering/res/values-ru/strings.xml b/Tethering/res/values-ru/strings.xml
new file mode 100644
index 0000000..7cb6f7d
--- /dev/null
+++ b/Tethering/res/values-ru/strings.xml
@@ -0,0 +1,29 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!--  Copyright (C) 2020 The Android Open Source Project
+
+     Licensed under the Apache License, Version 2.0 (the "License");
+     you may not use this file except in compliance with the License.
+     You may obtain a copy of the License at
+
+          http://www.apache.org/licenses/LICENSE-2.0
+
+     Unless required by applicable law or agreed to in writing, software
+     distributed under the License is distributed on an "AS IS" BASIS,
+     WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+     See the License for the specific language governing permissions and
+     limitations under the License.
+ -->
+
+<resources xmlns:android="http://schemas.android.com/apk/res/android"
+    xmlns:xliff="urn:oasis:names:tc:xliff:document:1.2">
+    <string name="tethered_notification_title" msgid="6426563586025792944">"Включен режим модема или точка доступа"</string>
+    <string name="tethered_notification_message" msgid="64800879503420696">"Нажмите, чтобы настроить."</string>
+    <string name="disable_tether_notification_title" msgid="3004509127903564191">"Использование телефона в качестве модема запрещено"</string>
+    <string name="disable_tether_notification_message" msgid="6717523799293901476">"Чтобы узнать подробности, обратитесь к администратору."</string>
+    <string name="notification_channel_tethering_status" msgid="2663463891530932727">"Статус хот-спота и режима модема"</string>
+    <string name="no_upstream_notification_title" msgid="1204601824631788482"></string>
+    <string name="no_upstream_notification_message" msgid="8586582938243032621"></string>
+    <string name="no_upstream_notification_disable_button" msgid="8800919436924640822"></string>
+    <string name="upstream_roaming_notification_title" msgid="4772373823198997030"></string>
+    <string name="upstream_roaming_notification_message" msgid="3985577843181551650"></string>
+</resources>
diff --git a/Tethering/res/values-si/strings.xml b/Tethering/res/values-si/strings.xml
new file mode 100644
index 0000000..ec34c22
--- /dev/null
+++ b/Tethering/res/values-si/strings.xml
@@ -0,0 +1,29 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!--  Copyright (C) 2020 The Android Open Source Project
+
+     Licensed under the Apache License, Version 2.0 (the "License");
+     you may not use this file except in compliance with the License.
+     You may obtain a copy of the License at
+
+          http://www.apache.org/licenses/LICENSE-2.0
+
+     Unless required by applicable law or agreed to in writing, software
+     distributed under the License is distributed on an "AS IS" BASIS,
+     WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+     See the License for the specific language governing permissions and
+     limitations under the License.
+ -->
+
+<resources xmlns:android="http://schemas.android.com/apk/res/android"
+    xmlns:xliff="urn:oasis:names:tc:xliff:document:1.2">
+    <string name="tethered_notification_title" msgid="6426563586025792944">"ටෙදරින් හෝ හොට්ස්පොට් සක්‍රීයයි"</string>
+    <string name="tethered_notification_message" msgid="64800879503420696">"පිහිටුවීමට තට්ටු කරන්න."</string>
+    <string name="disable_tether_notification_title" msgid="3004509127903564191">"ටෙදරින් අබල කර ඇත"</string>
+    <string name="disable_tether_notification_message" msgid="6717523799293901476">"විස්තර සඳහා ඔබගේ පරිපාලක අමතන්න"</string>
+    <string name="notification_channel_tethering_status" msgid="2663463891530932727">"හොට්ස්පොට් &amp; ටෙදරින් තත්ත්වය"</string>
+    <string name="no_upstream_notification_title" msgid="1204601824631788482"></string>
+    <string name="no_upstream_notification_message" msgid="8586582938243032621"></string>
+    <string name="no_upstream_notification_disable_button" msgid="8800919436924640822"></string>
+    <string name="upstream_roaming_notification_title" msgid="4772373823198997030"></string>
+    <string name="upstream_roaming_notification_message" msgid="3985577843181551650"></string>
+</resources>
diff --git a/Tethering/res/values-sk/strings.xml b/Tethering/res/values-sk/strings.xml
new file mode 100644
index 0000000..43e787c
--- /dev/null
+++ b/Tethering/res/values-sk/strings.xml
@@ -0,0 +1,29 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!--  Copyright (C) 2020 The Android Open Source Project
+
+     Licensed under the Apache License, Version 2.0 (the "License");
+     you may not use this file except in compliance with the License.
+     You may obtain a copy of the License at
+
+          http://www.apache.org/licenses/LICENSE-2.0
+
+     Unless required by applicable law or agreed to in writing, software
+     distributed under the License is distributed on an "AS IS" BASIS,
+     WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+     See the License for the specific language governing permissions and
+     limitations under the License.
+ -->
+
+<resources xmlns:android="http://schemas.android.com/apk/res/android"
+    xmlns:xliff="urn:oasis:names:tc:xliff:document:1.2">
+    <string name="tethered_notification_title" msgid="6426563586025792944">"Tethering alebo prístupový bod je aktívny"</string>
+    <string name="tethered_notification_message" msgid="64800879503420696">"Klepnutím prejdete na nastavenie."</string>
+    <string name="disable_tether_notification_title" msgid="3004509127903564191">"Tethering je deaktivovaný"</string>
+    <string name="disable_tether_notification_message" msgid="6717523799293901476">"O podrobnosti požiadajte svojho správcu"</string>
+    <string name="notification_channel_tethering_status" msgid="2663463891530932727">"Stav hotspotu a tetheringu"</string>
+    <string name="no_upstream_notification_title" msgid="1204601824631788482"></string>
+    <string name="no_upstream_notification_message" msgid="8586582938243032621"></string>
+    <string name="no_upstream_notification_disable_button" msgid="8800919436924640822"></string>
+    <string name="upstream_roaming_notification_title" msgid="4772373823198997030"></string>
+    <string name="upstream_roaming_notification_message" msgid="3985577843181551650"></string>
+</resources>
diff --git a/Tethering/res/values-sl/strings.xml b/Tethering/res/values-sl/strings.xml
new file mode 100644
index 0000000..5943362
--- /dev/null
+++ b/Tethering/res/values-sl/strings.xml
@@ -0,0 +1,29 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!--  Copyright (C) 2020 The Android Open Source Project
+
+     Licensed under the Apache License, Version 2.0 (the "License");
+     you may not use this file except in compliance with the License.
+     You may obtain a copy of the License at
+
+          http://www.apache.org/licenses/LICENSE-2.0
+
+     Unless required by applicable law or agreed to in writing, software
+     distributed under the License is distributed on an "AS IS" BASIS,
+     WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+     See the License for the specific language governing permissions and
+     limitations under the License.
+ -->
+
+<resources xmlns:android="http://schemas.android.com/apk/res/android"
+    xmlns:xliff="urn:oasis:names:tc:xliff:document:1.2">
+    <string name="tethered_notification_title" msgid="6426563586025792944">"Povezava z internetom prek mobilnega telefona ali dostopna točka je aktivna"</string>
+    <string name="tethered_notification_message" msgid="64800879503420696">"Dotaknite se, če želite nastaviti."</string>
+    <string name="disable_tether_notification_title" msgid="3004509127903564191">"Povezava z internetom prek mobilnega telefona je onemogočena"</string>
+    <string name="disable_tether_notification_message" msgid="6717523799293901476">"Za podrobnosti se obrnite na skrbnika"</string>
+    <string name="notification_channel_tethering_status" msgid="2663463891530932727">"Stanje dostopne točke in povezave z internetom prek mobilnega telefona"</string>
+    <string name="no_upstream_notification_title" msgid="1204601824631788482"></string>
+    <string name="no_upstream_notification_message" msgid="8586582938243032621"></string>
+    <string name="no_upstream_notification_disable_button" msgid="8800919436924640822"></string>
+    <string name="upstream_roaming_notification_title" msgid="4772373823198997030"></string>
+    <string name="upstream_roaming_notification_message" msgid="3985577843181551650"></string>
+</resources>
diff --git a/Tethering/res/values-sq/strings.xml b/Tethering/res/values-sq/strings.xml
new file mode 100644
index 0000000..21e1155
--- /dev/null
+++ b/Tethering/res/values-sq/strings.xml
@@ -0,0 +1,29 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!--  Copyright (C) 2020 The Android Open Source Project
+
+     Licensed under the Apache License, Version 2.0 (the "License");
+     you may not use this file except in compliance with the License.
+     You may obtain a copy of the License at
+
+          http://www.apache.org/licenses/LICENSE-2.0
+
+     Unless required by applicable law or agreed to in writing, software
+     distributed under the License is distributed on an "AS IS" BASIS,
+     WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+     See the License for the specific language governing permissions and
+     limitations under the License.
+ -->
+
+<resources xmlns:android="http://schemas.android.com/apk/res/android"
+    xmlns:xliff="urn:oasis:names:tc:xliff:document:1.2">
+    <string name="tethered_notification_title" msgid="6426563586025792944">"Ndarja e internetit ose zona e qasjes së internetit është aktive"</string>
+    <string name="tethered_notification_message" msgid="64800879503420696">"Trokit për ta konfiguruar."</string>
+    <string name="disable_tether_notification_title" msgid="3004509127903564191">"Ndarja e internetit është çaktivizuar"</string>
+    <string name="disable_tether_notification_message" msgid="6717523799293901476">"Kontakto me administratorin për detaje"</string>
+    <string name="notification_channel_tethering_status" msgid="2663463891530932727">"Statusi i zonës së qasjes dhe ndarjes së internetit"</string>
+    <string name="no_upstream_notification_title" msgid="1204601824631788482"></string>
+    <string name="no_upstream_notification_message" msgid="8586582938243032621"></string>
+    <string name="no_upstream_notification_disable_button" msgid="8800919436924640822"></string>
+    <string name="upstream_roaming_notification_title" msgid="4772373823198997030"></string>
+    <string name="upstream_roaming_notification_message" msgid="3985577843181551650"></string>
+</resources>
diff --git a/Tethering/res/values-sr/strings.xml b/Tethering/res/values-sr/strings.xml
new file mode 100644
index 0000000..e2e4dc6
--- /dev/null
+++ b/Tethering/res/values-sr/strings.xml
@@ -0,0 +1,29 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!--  Copyright (C) 2020 The Android Open Source Project
+
+     Licensed under the Apache License, Version 2.0 (the "License");
+     you may not use this file except in compliance with the License.
+     You may obtain a copy of the License at
+
+          http://www.apache.org/licenses/LICENSE-2.0
+
+     Unless required by applicable law or agreed to in writing, software
+     distributed under the License is distributed on an "AS IS" BASIS,
+     WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+     See the License for the specific language governing permissions and
+     limitations under the License.
+ -->
+
+<resources xmlns:android="http://schemas.android.com/apk/res/android"
+    xmlns:xliff="urn:oasis:names:tc:xliff:document:1.2">
+    <string name="tethered_notification_title" msgid="6426563586025792944">"Привезивање или хотспот је активан"</string>
+    <string name="tethered_notification_message" msgid="64800879503420696">"Додирните да бисте подесили."</string>
+    <string name="disable_tether_notification_title" msgid="3004509127903564191">"Привезивање је онемогућено"</string>
+    <string name="disable_tether_notification_message" msgid="6717523799293901476">"Потражите детаље од администратора"</string>
+    <string name="notification_channel_tethering_status" msgid="2663463891530932727">"Статус хотспота и привезивања"</string>
+    <string name="no_upstream_notification_title" msgid="1204601824631788482"></string>
+    <string name="no_upstream_notification_message" msgid="8586582938243032621"></string>
+    <string name="no_upstream_notification_disable_button" msgid="8800919436924640822"></string>
+    <string name="upstream_roaming_notification_title" msgid="4772373823198997030"></string>
+    <string name="upstream_roaming_notification_message" msgid="3985577843181551650"></string>
+</resources>
diff --git a/Tethering/res/values-sv/strings.xml b/Tethering/res/values-sv/strings.xml
new file mode 100644
index 0000000..72702c2
--- /dev/null
+++ b/Tethering/res/values-sv/strings.xml
@@ -0,0 +1,29 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!--  Copyright (C) 2020 The Android Open Source Project
+
+     Licensed under the Apache License, Version 2.0 (the "License");
+     you may not use this file except in compliance with the License.
+     You may obtain a copy of the License at
+
+          http://www.apache.org/licenses/LICENSE-2.0
+
+     Unless required by applicable law or agreed to in writing, software
+     distributed under the License is distributed on an "AS IS" BASIS,
+     WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+     See the License for the specific language governing permissions and
+     limitations under the License.
+ -->
+
+<resources xmlns:android="http://schemas.android.com/apk/res/android"
+    xmlns:xliff="urn:oasis:names:tc:xliff:document:1.2">
+    <string name="tethered_notification_title" msgid="6426563586025792944">"Internetdelning eller surfzon har aktiverats"</string>
+    <string name="tethered_notification_message" msgid="64800879503420696">"Tryck om du vill konfigurera."</string>
+    <string name="disable_tether_notification_title" msgid="3004509127903564191">"Internetdelning har inaktiverats"</string>
+    <string name="disable_tether_notification_message" msgid="6717523799293901476">"Kontakta administratören om du vill veta mer"</string>
+    <string name="notification_channel_tethering_status" msgid="2663463891530932727">"Trådlös surfzon och internetdelning har inaktiverats"</string>
+    <string name="no_upstream_notification_title" msgid="1204601824631788482"></string>
+    <string name="no_upstream_notification_message" msgid="8586582938243032621"></string>
+    <string name="no_upstream_notification_disable_button" msgid="8800919436924640822"></string>
+    <string name="upstream_roaming_notification_title" msgid="4772373823198997030"></string>
+    <string name="upstream_roaming_notification_message" msgid="3985577843181551650"></string>
+</resources>
diff --git a/Tethering/res/values-sw/strings.xml b/Tethering/res/values-sw/strings.xml
new file mode 100644
index 0000000..65e4aa8
--- /dev/null
+++ b/Tethering/res/values-sw/strings.xml
@@ -0,0 +1,29 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!--  Copyright (C) 2020 The Android Open Source Project
+
+     Licensed under the Apache License, Version 2.0 (the "License");
+     you may not use this file except in compliance with the License.
+     You may obtain a copy of the License at
+
+          http://www.apache.org/licenses/LICENSE-2.0
+
+     Unless required by applicable law or agreed to in writing, software
+     distributed under the License is distributed on an "AS IS" BASIS,
+     WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+     See the License for the specific language governing permissions and
+     limitations under the License.
+ -->
+
+<resources xmlns:android="http://schemas.android.com/apk/res/android"
+    xmlns:xliff="urn:oasis:names:tc:xliff:document:1.2">
+    <string name="tethered_notification_title" msgid="6426563586025792944">"Kusambaza mtandao au mtandaopepe umewashwa"</string>
+    <string name="tethered_notification_message" msgid="64800879503420696">"Gusa ili uweke mipangilio."</string>
+    <string name="disable_tether_notification_title" msgid="3004509127903564191">"Umezima kipengele cha kusambaza mtandao"</string>
+    <string name="disable_tether_notification_message" msgid="6717523799293901476">"Wasiliana na msimamizi wako ili upate maelezo zaidi"</string>
+    <string name="notification_channel_tethering_status" msgid="2663463891530932727">"Mtandaopepe na hali ya kusambaza mtandao"</string>
+    <string name="no_upstream_notification_title" msgid="1204601824631788482"></string>
+    <string name="no_upstream_notification_message" msgid="8586582938243032621"></string>
+    <string name="no_upstream_notification_disable_button" msgid="8800919436924640822"></string>
+    <string name="upstream_roaming_notification_title" msgid="4772373823198997030"></string>
+    <string name="upstream_roaming_notification_message" msgid="3985577843181551650"></string>
+</resources>
diff --git a/Tethering/res/values-ta/strings.xml b/Tethering/res/values-ta/strings.xml
new file mode 100644
index 0000000..4aba62d
--- /dev/null
+++ b/Tethering/res/values-ta/strings.xml
@@ -0,0 +1,29 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!--  Copyright (C) 2020 The Android Open Source Project
+
+     Licensed under the Apache License, Version 2.0 (the "License");
+     you may not use this file except in compliance with the License.
+     You may obtain a copy of the License at
+
+          http://www.apache.org/licenses/LICENSE-2.0
+
+     Unless required by applicable law or agreed to in writing, software
+     distributed under the License is distributed on an "AS IS" BASIS,
+     WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+     See the License for the specific language governing permissions and
+     limitations under the License.
+ -->
+
+<resources xmlns:android="http://schemas.android.com/apk/res/android"
+    xmlns:xliff="urn:oasis:names:tc:xliff:document:1.2">
+    <string name="tethered_notification_title" msgid="6426563586025792944">"டெதெரிங் அல்லது ஹாட்ஸ்பாட் இயங்குகிறது"</string>
+    <string name="tethered_notification_message" msgid="64800879503420696">"அமைக்க, தட்டவும்."</string>
+    <string name="disable_tether_notification_title" msgid="3004509127903564191">"டெதெரிங் முடக்கப்பட்டுள்ளது"</string>
+    <string name="disable_tether_notification_message" msgid="6717523799293901476">"விவரங்களுக்கு உங்கள் நிர்வாகியைத் தொடர்புகொள்ளவும்"</string>
+    <string name="notification_channel_tethering_status" msgid="2663463891530932727">"ஹாட்ஸ்பாட் &amp; டெதெரிங் நிலை"</string>
+    <string name="no_upstream_notification_title" msgid="1204601824631788482"></string>
+    <string name="no_upstream_notification_message" msgid="8586582938243032621"></string>
+    <string name="no_upstream_notification_disable_button" msgid="8800919436924640822"></string>
+    <string name="upstream_roaming_notification_title" msgid="4772373823198997030"></string>
+    <string name="upstream_roaming_notification_message" msgid="3985577843181551650"></string>
+</resources>
diff --git a/Tethering/res/values-te/strings.xml b/Tethering/res/values-te/strings.xml
new file mode 100644
index 0000000..1f91791
--- /dev/null
+++ b/Tethering/res/values-te/strings.xml
@@ -0,0 +1,29 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!--  Copyright (C) 2020 The Android Open Source Project
+
+     Licensed under the Apache License, Version 2.0 (the "License");
+     you may not use this file except in compliance with the License.
+     You may obtain a copy of the License at
+
+          http://www.apache.org/licenses/LICENSE-2.0
+
+     Unless required by applicable law or agreed to in writing, software
+     distributed under the License is distributed on an "AS IS" BASIS,
+     WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+     See the License for the specific language governing permissions and
+     limitations under the License.
+ -->
+
+<resources xmlns:android="http://schemas.android.com/apk/res/android"
+    xmlns:xliff="urn:oasis:names:tc:xliff:document:1.2">
+    <string name="tethered_notification_title" msgid="6426563586025792944">"టెథరింగ్ లేదా హాట్‌స్పాట్ యాక్టివ్‌గా ఉంది"</string>
+    <string name="tethered_notification_message" msgid="64800879503420696">"సెటప్ చేయడానికి ట్యాప్ చేయండి."</string>
+    <string name="disable_tether_notification_title" msgid="3004509127903564191">"టెథరింగ్ డిజేబుల్ చేయబడింది"</string>
+    <string name="disable_tether_notification_message" msgid="6717523799293901476">"వివరాల కోసం మీ అడ్మిన్‌ని సంప్రదించండి"</string>
+    <string name="notification_channel_tethering_status" msgid="2663463891530932727">"హాట్‌స్పాట్ &amp; టెథరింగ్ స్థితి"</string>
+    <string name="no_upstream_notification_title" msgid="1204601824631788482"></string>
+    <string name="no_upstream_notification_message" msgid="8586582938243032621"></string>
+    <string name="no_upstream_notification_disable_button" msgid="8800919436924640822"></string>
+    <string name="upstream_roaming_notification_title" msgid="4772373823198997030"></string>
+    <string name="upstream_roaming_notification_message" msgid="3985577843181551650"></string>
+</resources>
diff --git a/Tethering/res/values-th/strings.xml b/Tethering/res/values-th/strings.xml
new file mode 100644
index 0000000..44171c0
--- /dev/null
+++ b/Tethering/res/values-th/strings.xml
@@ -0,0 +1,29 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!--  Copyright (C) 2020 The Android Open Source Project
+
+     Licensed under the Apache License, Version 2.0 (the "License");
+     you may not use this file except in compliance with the License.
+     You may obtain a copy of the License at
+
+          http://www.apache.org/licenses/LICENSE-2.0
+
+     Unless required by applicable law or agreed to in writing, software
+     distributed under the License is distributed on an "AS IS" BASIS,
+     WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+     See the License for the specific language governing permissions and
+     limitations under the License.
+ -->
+
+<resources xmlns:android="http://schemas.android.com/apk/res/android"
+    xmlns:xliff="urn:oasis:names:tc:xliff:document:1.2">
+    <string name="tethered_notification_title" msgid="6426563586025792944">"การเชื่อมต่ออินเทอร์เน็ตผ่านมือถือหรือฮอตสปอตทำงานอยู่"</string>
+    <string name="tethered_notification_message" msgid="64800879503420696">"แตะเพื่อตั้งค่า"</string>
+    <string name="disable_tether_notification_title" msgid="3004509127903564191">"ปิดใช้การเชื่อมต่ออินเทอร์เน็ตผ่านมือถือแล้ว"</string>
+    <string name="disable_tether_notification_message" msgid="6717523799293901476">"ติดต่อผู้ดูแลระบบเพื่อขอรายละเอียด"</string>
+    <string name="notification_channel_tethering_status" msgid="2663463891530932727">"สถานะฮอตสปอตและการเชื่อมต่ออินเทอร์เน็ตผ่านมือถือ"</string>
+    <string name="no_upstream_notification_title" msgid="1204601824631788482"></string>
+    <string name="no_upstream_notification_message" msgid="8586582938243032621"></string>
+    <string name="no_upstream_notification_disable_button" msgid="8800919436924640822"></string>
+    <string name="upstream_roaming_notification_title" msgid="4772373823198997030"></string>
+    <string name="upstream_roaming_notification_message" msgid="3985577843181551650"></string>
+</resources>
diff --git a/Tethering/res/values-tl/strings.xml b/Tethering/res/values-tl/strings.xml
new file mode 100644
index 0000000..7347dd3
--- /dev/null
+++ b/Tethering/res/values-tl/strings.xml
@@ -0,0 +1,29 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!--  Copyright (C) 2020 The Android Open Source Project
+
+     Licensed under the Apache License, Version 2.0 (the "License");
+     you may not use this file except in compliance with the License.
+     You may obtain a copy of the License at
+
+          http://www.apache.org/licenses/LICENSE-2.0
+
+     Unless required by applicable law or agreed to in writing, software
+     distributed under the License is distributed on an "AS IS" BASIS,
+     WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+     See the License for the specific language governing permissions and
+     limitations under the License.
+ -->
+
+<resources xmlns:android="http://schemas.android.com/apk/res/android"
+    xmlns:xliff="urn:oasis:names:tc:xliff:document:1.2">
+    <string name="tethered_notification_title" msgid="6426563586025792944">"Aktibo ang pag-tether o hotspot"</string>
+    <string name="tethered_notification_message" msgid="64800879503420696">"I-tap para i-set up."</string>
+    <string name="disable_tether_notification_title" msgid="3004509127903564191">"Naka-disable ang pag-tether"</string>
+    <string name="disable_tether_notification_message" msgid="6717523799293901476">"Makipag-ugnayan sa iyong admin para sa mga detalye"</string>
+    <string name="notification_channel_tethering_status" msgid="2663463891530932727">"Status ng hotspot at pag-tether"</string>
+    <string name="no_upstream_notification_title" msgid="1204601824631788482"></string>
+    <string name="no_upstream_notification_message" msgid="8586582938243032621"></string>
+    <string name="no_upstream_notification_disable_button" msgid="8800919436924640822"></string>
+    <string name="upstream_roaming_notification_title" msgid="4772373823198997030"></string>
+    <string name="upstream_roaming_notification_message" msgid="3985577843181551650"></string>
+</resources>
diff --git a/Tethering/res/values-tr/strings.xml b/Tethering/res/values-tr/strings.xml
new file mode 100644
index 0000000..32030f1
--- /dev/null
+++ b/Tethering/res/values-tr/strings.xml
@@ -0,0 +1,29 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!--  Copyright (C) 2020 The Android Open Source Project
+
+     Licensed under the Apache License, Version 2.0 (the "License");
+     you may not use this file except in compliance with the License.
+     You may obtain a copy of the License at
+
+          http://www.apache.org/licenses/LICENSE-2.0
+
+     Unless required by applicable law or agreed to in writing, software
+     distributed under the License is distributed on an "AS IS" BASIS,
+     WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+     See the License for the specific language governing permissions and
+     limitations under the License.
+ -->
+
+<resources xmlns:android="http://schemas.android.com/apk/res/android"
+    xmlns:xliff="urn:oasis:names:tc:xliff:document:1.2">
+    <string name="tethered_notification_title" msgid="6426563586025792944">"Tethering veya hotspot etkin"</string>
+    <string name="tethered_notification_message" msgid="64800879503420696">"Ayarlamak için dokunun."</string>
+    <string name="disable_tether_notification_title" msgid="3004509127903564191">"Tethering devre dışı bırakıldı"</string>
+    <string name="disable_tether_notification_message" msgid="6717523799293901476">"Ayrıntılı bilgi için yöneticinize başvurun"</string>
+    <string name="notification_channel_tethering_status" msgid="2663463891530932727">"Hotspot ve tethering durumu"</string>
+    <string name="no_upstream_notification_title" msgid="1204601824631788482"></string>
+    <string name="no_upstream_notification_message" msgid="8586582938243032621"></string>
+    <string name="no_upstream_notification_disable_button" msgid="8800919436924640822"></string>
+    <string name="upstream_roaming_notification_title" msgid="4772373823198997030"></string>
+    <string name="upstream_roaming_notification_message" msgid="3985577843181551650"></string>
+</resources>
diff --git a/Tethering/res/values-uk/strings.xml b/Tethering/res/values-uk/strings.xml
new file mode 100644
index 0000000..1ca89b3
--- /dev/null
+++ b/Tethering/res/values-uk/strings.xml
@@ -0,0 +1,29 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!--  Copyright (C) 2020 The Android Open Source Project
+
+     Licensed under the Apache License, Version 2.0 (the "License");
+     you may not use this file except in compliance with the License.
+     You may obtain a copy of the License at
+
+          http://www.apache.org/licenses/LICENSE-2.0
+
+     Unless required by applicable law or agreed to in writing, software
+     distributed under the License is distributed on an "AS IS" BASIS,
+     WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+     See the License for the specific language governing permissions and
+     limitations under the License.
+ -->
+
+<resources xmlns:android="http://schemas.android.com/apk/res/android"
+    xmlns:xliff="urn:oasis:names:tc:xliff:document:1.2">
+    <string name="tethered_notification_title" msgid="6426563586025792944">"Модем чи точка доступу активні"</string>
+    <string name="tethered_notification_message" msgid="64800879503420696">"Натисніть, щоб налаштувати."</string>
+    <string name="disable_tether_notification_title" msgid="3004509127903564191">"Використання телефона як модема вимкнено"</string>
+    <string name="disable_tether_notification_message" msgid="6717523799293901476">"Щоб дізнатися більше, зв\'яжіться з адміністратором"</string>
+    <string name="notification_channel_tethering_status" msgid="2663463891530932727">"Статус точки доступу та модема"</string>
+    <string name="no_upstream_notification_title" msgid="1204601824631788482"></string>
+    <string name="no_upstream_notification_message" msgid="8586582938243032621"></string>
+    <string name="no_upstream_notification_disable_button" msgid="8800919436924640822"></string>
+    <string name="upstream_roaming_notification_title" msgid="4772373823198997030"></string>
+    <string name="upstream_roaming_notification_message" msgid="3985577843181551650"></string>
+</resources>
diff --git a/Tethering/res/values-ur/strings.xml b/Tethering/res/values-ur/strings.xml
new file mode 100644
index 0000000..d72c7d4
--- /dev/null
+++ b/Tethering/res/values-ur/strings.xml
@@ -0,0 +1,29 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!--  Copyright (C) 2020 The Android Open Source Project
+
+     Licensed under the Apache License, Version 2.0 (the "License");
+     you may not use this file except in compliance with the License.
+     You may obtain a copy of the License at
+
+          http://www.apache.org/licenses/LICENSE-2.0
+
+     Unless required by applicable law or agreed to in writing, software
+     distributed under the License is distributed on an "AS IS" BASIS,
+     WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+     See the License for the specific language governing permissions and
+     limitations under the License.
+ -->
+
+<resources xmlns:android="http://schemas.android.com/apk/res/android"
+    xmlns:xliff="urn:oasis:names:tc:xliff:document:1.2">
+    <string name="tethered_notification_title" msgid="6426563586025792944">"ٹیدرنگ یا ہاٹ اسپاٹ فعال"</string>
+    <string name="tethered_notification_message" msgid="64800879503420696">"سیٹ اپ کرنے کیلئے تھپتھپائیں۔"</string>
+    <string name="disable_tether_notification_title" msgid="3004509127903564191">"ٹیدرنگ غیر فعال ہے"</string>
+    <string name="disable_tether_notification_message" msgid="6717523799293901476">"تفصیلات کے لئے اپنے منتظم سے رابطہ کریں"</string>
+    <string name="notification_channel_tethering_status" msgid="2663463891530932727">"ہاٹ اسپاٹ اور ٹیتھرنگ کا اسٹیٹس"</string>
+    <string name="no_upstream_notification_title" msgid="1204601824631788482"></string>
+    <string name="no_upstream_notification_message" msgid="8586582938243032621"></string>
+    <string name="no_upstream_notification_disable_button" msgid="8800919436924640822"></string>
+    <string name="upstream_roaming_notification_title" msgid="4772373823198997030"></string>
+    <string name="upstream_roaming_notification_message" msgid="3985577843181551650"></string>
+</resources>
diff --git a/Tethering/res/values-uz/strings.xml b/Tethering/res/values-uz/strings.xml
new file mode 100644
index 0000000..af3b2eb
--- /dev/null
+++ b/Tethering/res/values-uz/strings.xml
@@ -0,0 +1,29 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!--  Copyright (C) 2020 The Android Open Source Project
+
+     Licensed under the Apache License, Version 2.0 (the "License");
+     you may not use this file except in compliance with the License.
+     You may obtain a copy of the License at
+
+          http://www.apache.org/licenses/LICENSE-2.0
+
+     Unless required by applicable law or agreed to in writing, software
+     distributed under the License is distributed on an "AS IS" BASIS,
+     WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+     See the License for the specific language governing permissions and
+     limitations under the License.
+ -->
+
+<resources xmlns:android="http://schemas.android.com/apk/res/android"
+    xmlns:xliff="urn:oasis:names:tc:xliff:document:1.2">
+    <string name="tethered_notification_title" msgid="6426563586025792944">"Modem rejimi yoki hotspot yoniq"</string>
+    <string name="tethered_notification_message" msgid="64800879503420696">"Sozlash uchun bosing."</string>
+    <string name="disable_tether_notification_title" msgid="3004509127903564191">"Modem rejimi faolsizlantirildi"</string>
+    <string name="disable_tether_notification_message" msgid="6717523799293901476">"Tafsilotlari uchun administratoringizga murojaat qiling"</string>
+    <string name="notification_channel_tethering_status" msgid="2663463891530932727">"Hotspot va modem rejimi holati"</string>
+    <string name="no_upstream_notification_title" msgid="1204601824631788482"></string>
+    <string name="no_upstream_notification_message" msgid="8586582938243032621"></string>
+    <string name="no_upstream_notification_disable_button" msgid="8800919436924640822"></string>
+    <string name="upstream_roaming_notification_title" msgid="4772373823198997030"></string>
+    <string name="upstream_roaming_notification_message" msgid="3985577843181551650"></string>
+</resources>
diff --git a/Tethering/res/values-vi/strings.xml b/Tethering/res/values-vi/strings.xml
new file mode 100644
index 0000000..21a0735
--- /dev/null
+++ b/Tethering/res/values-vi/strings.xml
@@ -0,0 +1,29 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!--  Copyright (C) 2020 The Android Open Source Project
+
+     Licensed under the Apache License, Version 2.0 (the "License");
+     you may not use this file except in compliance with the License.
+     You may obtain a copy of the License at
+
+          http://www.apache.org/licenses/LICENSE-2.0
+
+     Unless required by applicable law or agreed to in writing, software
+     distributed under the License is distributed on an "AS IS" BASIS,
+     WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+     See the License for the specific language governing permissions and
+     limitations under the License.
+ -->
+
+<resources xmlns:android="http://schemas.android.com/apk/res/android"
+    xmlns:xliff="urn:oasis:names:tc:xliff:document:1.2">
+    <string name="tethered_notification_title" msgid="6426563586025792944">"Tính năng chia sẻ Internet hoặc điểm phát sóng đang hoạt động"</string>
+    <string name="tethered_notification_message" msgid="64800879503420696">"Hãy nhấn để thiết lập."</string>
+    <string name="disable_tether_notification_title" msgid="3004509127903564191">"Đã tắt tính năng chia sẻ Internet"</string>
+    <string name="disable_tether_notification_message" msgid="6717523799293901476">"Hãy liên hệ với quản trị viên của bạn để biết chi tiết"</string>
+    <string name="notification_channel_tethering_status" msgid="2663463891530932727">"Trạng thái điểm phát sóng và chia sẻ Internet"</string>
+    <string name="no_upstream_notification_title" msgid="1204601824631788482"></string>
+    <string name="no_upstream_notification_message" msgid="8586582938243032621"></string>
+    <string name="no_upstream_notification_disable_button" msgid="8800919436924640822"></string>
+    <string name="upstream_roaming_notification_title" msgid="4772373823198997030"></string>
+    <string name="upstream_roaming_notification_message" msgid="3985577843181551650"></string>
+</resources>
diff --git a/Tethering/res/values-zh-rCN/strings.xml b/Tethering/res/values-zh-rCN/strings.xml
new file mode 100644
index 0000000..98e3b4b
--- /dev/null
+++ b/Tethering/res/values-zh-rCN/strings.xml
@@ -0,0 +1,29 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!--  Copyright (C) 2020 The Android Open Source Project
+
+     Licensed under the Apache License, Version 2.0 (the "License");
+     you may not use this file except in compliance with the License.
+     You may obtain a copy of the License at
+
+          http://www.apache.org/licenses/LICENSE-2.0
+
+     Unless required by applicable law or agreed to in writing, software
+     distributed under the License is distributed on an "AS IS" BASIS,
+     WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+     See the License for the specific language governing permissions and
+     limitations under the License.
+ -->
+
+<resources xmlns:android="http://schemas.android.com/apk/res/android"
+    xmlns:xliff="urn:oasis:names:tc:xliff:document:1.2">
+    <string name="tethered_notification_title" msgid="6426563586025792944">"网络共享或热点已启用"</string>
+    <string name="tethered_notification_message" msgid="64800879503420696">"点按即可设置。"</string>
+    <string name="disable_tether_notification_title" msgid="3004509127903564191">"网络共享已停用"</string>
+    <string name="disable_tether_notification_message" msgid="6717523799293901476">"如需了解详情，请与您的管理员联系"</string>
+    <string name="notification_channel_tethering_status" msgid="2663463891530932727">"热点和网络共享状态"</string>
+    <string name="no_upstream_notification_title" msgid="1204601824631788482"></string>
+    <string name="no_upstream_notification_message" msgid="8586582938243032621"></string>
+    <string name="no_upstream_notification_disable_button" msgid="8800919436924640822"></string>
+    <string name="upstream_roaming_notification_title" msgid="4772373823198997030"></string>
+    <string name="upstream_roaming_notification_message" msgid="3985577843181551650"></string>
+</resources>
diff --git a/Tethering/res/values-zh-rHK/strings.xml b/Tethering/res/values-zh-rHK/strings.xml
new file mode 100644
index 0000000..9cafd42
--- /dev/null
+++ b/Tethering/res/values-zh-rHK/strings.xml
@@ -0,0 +1,29 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!--  Copyright (C) 2020 The Android Open Source Project
+
+     Licensed under the Apache License, Version 2.0 (the "License");
+     you may not use this file except in compliance with the License.
+     You may obtain a copy of the License at
+
+          http://www.apache.org/licenses/LICENSE-2.0
+
+     Unless required by applicable law or agreed to in writing, software
+     distributed under the License is distributed on an "AS IS" BASIS,
+     WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+     See the License for the specific language governing permissions and
+     limitations under the License.
+ -->
+
+<resources xmlns:android="http://schemas.android.com/apk/res/android"
+    xmlns:xliff="urn:oasis:names:tc:xliff:document:1.2">
+    <string name="tethered_notification_title" msgid="6426563586025792944">"網絡共享或熱點已啟用"</string>
+    <string name="tethered_notification_message" msgid="64800879503420696">"輕按即可設定。"</string>
+    <string name="disable_tether_notification_title" msgid="3004509127903564191">"網絡共享已停用"</string>
+    <string name="disable_tether_notification_message" msgid="6717523799293901476">"請聯絡您的管理員以瞭解詳情"</string>
+    <string name="notification_channel_tethering_status" msgid="2663463891530932727">"熱點和網絡共享狀態"</string>
+    <string name="no_upstream_notification_title" msgid="1204601824631788482"></string>
+    <string name="no_upstream_notification_message" msgid="8586582938243032621"></string>
+    <string name="no_upstream_notification_disable_button" msgid="8800919436924640822"></string>
+    <string name="upstream_roaming_notification_title" msgid="4772373823198997030"></string>
+    <string name="upstream_roaming_notification_message" msgid="3985577843181551650"></string>
+</resources>
diff --git a/Tethering/res/values-zh-rTW/strings.xml b/Tethering/res/values-zh-rTW/strings.xml
new file mode 100644
index 0000000..50a50bf
--- /dev/null
+++ b/Tethering/res/values-zh-rTW/strings.xml
@@ -0,0 +1,29 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!--  Copyright (C) 2020 The Android Open Source Project
+
+     Licensed under the Apache License, Version 2.0 (the "License");
+     you may not use this file except in compliance with the License.
+     You may obtain a copy of the License at
+
+          http://www.apache.org/licenses/LICENSE-2.0
+
+     Unless required by applicable law or agreed to in writing, software
+     distributed under the License is distributed on an "AS IS" BASIS,
+     WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+     See the License for the specific language governing permissions and
+     limitations under the License.
+ -->
+
+<resources xmlns:android="http://schemas.android.com/apk/res/android"
+    xmlns:xliff="urn:oasis:names:tc:xliff:document:1.2">
+    <string name="tethered_notification_title" msgid="6426563586025792944">"網路共用或無線基地台已啟用"</string>
+    <string name="tethered_notification_message" msgid="64800879503420696">"輕觸即可進行設定。"</string>
+    <string name="disable_tether_notification_title" msgid="3004509127903564191">"網路共用已停用"</string>
+    <string name="disable_tether_notification_message" msgid="6717523799293901476">"詳情請洽你的管理員"</string>
+    <string name="notification_channel_tethering_status" msgid="2663463891530932727">"無線基地台與網路共用狀態"</string>
+    <string name="no_upstream_notification_title" msgid="1204601824631788482"></string>
+    <string name="no_upstream_notification_message" msgid="8586582938243032621"></string>
+    <string name="no_upstream_notification_disable_button" msgid="8800919436924640822"></string>
+    <string name="upstream_roaming_notification_title" msgid="4772373823198997030"></string>
+    <string name="upstream_roaming_notification_message" msgid="3985577843181551650"></string>
+</resources>
diff --git a/Tethering/res/values-zu/strings.xml b/Tethering/res/values-zu/strings.xml
new file mode 100644
index 0000000..f210f87
--- /dev/null
+++ b/Tethering/res/values-zu/strings.xml
@@ -0,0 +1,29 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!--  Copyright (C) 2020 The Android Open Source Project
+
+     Licensed under the Apache License, Version 2.0 (the "License");
+     you may not use this file except in compliance with the License.
+     You may obtain a copy of the License at
+
+          http://www.apache.org/licenses/LICENSE-2.0
+
+     Unless required by applicable law or agreed to in writing, software
+     distributed under the License is distributed on an "AS IS" BASIS,
+     WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+     See the License for the specific language governing permissions and
+     limitations under the License.
+ -->
+
+<resources xmlns:android="http://schemas.android.com/apk/res/android"
+    xmlns:xliff="urn:oasis:names:tc:xliff:document:1.2">
+    <string name="tethered_notification_title" msgid="6426563586025792944">"Ukusebenzisa njengemodemu noma i-hotspot ephathekayo kuvuliwe"</string>
+    <string name="tethered_notification_message" msgid="64800879503420696">"Thepha ukuze usethe."</string>
+    <string name="disable_tether_notification_title" msgid="3004509127903564191">"Ukusebenzisa ifoni njengemodemu kukhutshaziwe"</string>
+    <string name="disable_tether_notification_message" msgid="6717523799293901476">"Xhumana nomphathi wakho ukuze uthole imininingwane"</string>
+    <string name="notification_channel_tethering_status" msgid="2663463891530932727">"I-Hotspot nesimo sokusebenzisa ifoni njengemodemu"</string>
+    <string name="no_upstream_notification_title" msgid="1204601824631788482"></string>
+    <string name="no_upstream_notification_message" msgid="8586582938243032621"></string>
+    <string name="no_upstream_notification_disable_button" msgid="8800919436924640822"></string>
+    <string name="upstream_roaming_notification_title" msgid="4772373823198997030"></string>
+    <string name="upstream_roaming_notification_message" msgid="3985577843181551650"></string>
+</resources>
diff --git a/Tethering/res/values/config.xml b/Tethering/res/values/config.xml
new file mode 100644
index 0000000..5f8d299
--- /dev/null
+++ b/Tethering/res/values/config.xml
@@ -0,0 +1,194 @@
+<?xml version="1.0" encoding="utf-8"?>
+<!-- Copyright (C) 2020 The Android Open Source Project
+
+     Licensed under the Apache License, Version 2.0 (the "License");
+     you may not use this file except in compliance with the License.
+     You may obtain a copy of the License at
+
+          http://www.apache.org/licenses/LICENSE-2.0
+
+     Unless required by applicable law or agreed to in writing, software
+     distributed under the License is distributed on an "AS IS" BASIS,
+     WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+     See the License for the specific language governing permissions and
+     limitations under the License.
+-->
+<resources>
+    <!--
+    OEMs that wish to change the below settings must do so via a runtime resource overlay package
+    and *NOT* by changing this file. This file is part of the tethering mainline module.
+    TODO: define two resources for each config item: a default_* resource and a config_* resource,
+    config_* is empty by default but may be overridden by RROs.
+    -->
+    <!-- List of regexpressions describing the interface (if any) that represent tetherable
+         USB interfaces.  If the device doesn't want to support tethering over USB this should
+         be empty.  An example would be "usb.*" -->
+    <string-array translatable="false" name="config_tether_usb_regexs">
+        <item>"usb\\d"</item>
+        <item>"rndis\\d"</item>
+    </string-array>
+
+    <!-- List of regexpressions describing the interface (if any) that represent tetherable
+         NCM interfaces.  If the device doesn't want to support tethering over NCM this should
+         be empty. -->
+    <string-array translatable="false" name="config_tether_ncm_regexs">
+    </string-array>
+
+    <!-- List of regexpressions describing the interface (if any) that represent tetherable
+         Wifi interfaces.  If the device doesn't want to support tethering over Wifi this
+         should be empty.  An example would be "softap.*" -->
+    <string-array translatable="false" name="config_tether_wifi_regexs">
+        <item>"wlan\\d"</item>
+        <item>"softap\\d"</item>
+    </string-array>
+
+    <!-- List of regexpressions describing the interface (if any) that represent tetherable
+         WiGig interfaces.  If the device doesn't want to support tethering over WiGig this
+         should be empty.  An example would be "wigig\\d" -->
+    <string-array translatable="false" name="config_tether_wigig_regexs">
+        <item>"wigig\\d"</item>
+    </string-array>
+
+    <!-- List of regexpressions describing the interface (if any) that represent tetherable
+         Wifi P2P interfaces.  If the device doesn't want to support tethering over Wifi P2p this
+         should be empty.  An example would be "p2p-p2p\\d-.*" -->
+    <string-array translatable="false" name="config_tether_wifi_p2p_regexs">
+        <item>"p2p-p2p\\d-.*"</item>
+        <item>"p2p\\d"</item>
+    </string-array>
+
+    <!-- List of regexpressions describing the interface (if any) that represent tetherable
+         bluetooth interfaces.  If the device doesn't want to support tethering over bluetooth this
+         should be empty. -->
+    <string-array translatable="false" name="config_tether_bluetooth_regexs">
+        <item>"bt-pan"</item>
+    </string-array>
+
+    <!-- Use the BPF offload for tethering when the kernel has support. True by default.
+         If the device doesn't want to support tether BPF offload, this should be false.
+         Note that this setting could be overridden by device config.
+    -->
+    <bool translatable="false" name="config_tether_enable_bpf_offload">true</bool>
+
+    <!-- Use the old dnsmasq DHCP server for tethering instead of the framework implementation. -->
+    <bool translatable="false" name="config_tether_enable_legacy_dhcp_server">false</bool>
+
+    <!-- Use legacy wifi p2p dedicated address instead of randomize address. -->
+    <bool translatable="false" name="config_tether_enable_legacy_wifi_p2p_dedicated_ip">false</bool>
+
+    <!-- Dhcp range (min, max) to use for tethering purposes -->
+    <string-array translatable="false" name="config_tether_dhcp_range">
+    </string-array>
+
+    <!-- Used to config periodic polls tether offload stats from tethering offload HAL to make the
+     data warnings work. 5000(ms) by default. If the device doesn't want to poll tether
+     offload stats, this should be -1. Note that this setting could be override by
+     runtime resource overlays.
+    -->
+    <integer translatable="false" name="config_tether_offload_poll_interval">5000</integer>
+
+    <!-- Array of ConnectivityManager.TYPE_{BLUETOOTH, ETHERNET, MOBILE, MOBILE_DUN, MOBILE_HIPRI,
+         WIFI} values allowable for tethering.
+
+         Common options are [1, 4] for TYPE_WIFI and TYPE_MOBILE_DUN or
+         [1,7,0] for TYPE_WIFI, TYPE_BLUETOOTH, and TYPE_MOBILE.
+
+         This list is also modified by code within the framework, including:
+
+             - TYPE_ETHERNET (9) is prepended to this list, and
+
+             - the return value of TelephonyManager.isTetheringApnRequired()
+               determines how the array is further modified:
+
+                   * TRUE (DUN REQUIRED).
+                     TYPE_MOBILE is removed (if present).
+                     TYPE_MOBILE_HIPRI is removed (if present).
+                     TYPE_MOBILE_DUN is appended (if not already present).
+
+                   * FALSE (DUN NOT REQUIRED).
+                     TYPE_MOBILE_DUN is removed (if present).
+                     If both of TYPE_MOBILE{,_HIPRI} are not present:
+                        TYPE_MOBILE is appended.
+                        TYPE_MOBILE_HIPRI is appended.
+
+         For other changes applied to this list, now and in the future, see
+         com.android.networkstack.tethering.TetheringConfiguration.
+
+         Note also: the order of this is important. The first upstream type
+         for which a satisfying network exists is used.
+    -->
+    <integer-array translatable="false" name="config_tether_upstream_types">
+    </integer-array>
+
+    <!-- When true, the tethering upstream network follows the current default
+         Internet network (except when the current default network is mobile,
+         in which case a DUN network will be used if required).
+
+         When true, overrides the config_tether_upstream_types setting above.
+    -->
+    <bool translatable="false" name="config_tether_upstream_automatic">true</bool>
+
+
+    <!-- If the mobile hotspot feature requires provisioning, a package name and class name
+         can be provided to launch a supported application that provisions the devices.
+         EntitlementManager will send an intent to Settings with the specified package name and
+         class name in extras to launch provision app.
+         TODO: note what extras here.
+
+         See EntitlementManager#runUiTetherProvisioning and
+         packages/apps/Settings/src/com/android/settings/network/TetherProvisioningActivity.java
+         for more details.
+
+         For ui-less/periodic recheck support see config_mobile_hotspot_provision_app_no_ui
+        -->
+    <!-- The first element is the package name and the second element is the class name
+         of the provisioning app -->
+    <string-array translatable="false" name="config_mobile_hotspot_provision_app">
+    <!--
+        <item>com.example.provisioning</item>
+        <item>com.example.provisioning.Activity</item>
+    -->
+    </string-array>
+
+    <!-- If the mobile hotspot feature requires provisioning, an action can be provided
+         that will be broadcast in non-ui cases for checking the provisioning status.
+         EntitlementManager will pass the specified name to Settings and Settings would
+         launch provisioning app by sending an intent with the package name.
+
+         A second broadcast, action defined by config_mobile_hotspot_provision_response,
+         will be sent back to notify if provisioning succeeded or not.  The response will
+         match that of the activity in config_mobile_hotspot_provision_app, but instead
+         contained within the int extra "EntitlementResult".
+         TODO: provide the system api for "EntitlementResult" extra and note it here.
+
+         See EntitlementManager#runSilentTetherProvisioning and
+         packages/apps/Settings/src/com/android/settings/wifi/tether/TetherService.java for more
+         details.
+        -->
+    <string translatable="false" name="config_mobile_hotspot_provision_app_no_ui"></string>
+
+    <!-- Sent in response to a provisioning check. The caller must hold the
+         permission android.permission.TETHER_PRIVILEGED for Settings to
+         receive this response.
+
+         See config_mobile_hotspot_provision_response
+         -->
+    <string translatable="false" name="config_mobile_hotspot_provision_response"></string>
+
+    <!-- Number of hours between each background provisioning call -->
+    <integer translatable="false" name="config_mobile_hotspot_provision_check_period">24</integer>
+
+    <!-- ComponentName of the service used to run no ui tether provisioning. -->
+    <string translatable="false" name="config_wifi_tether_enable">com.android.settings/.wifi.tether.TetherService</string>
+
+    <!-- No upstream notification is shown when there is a downstream but no upstream that is able
+         to do the tethering. -->
+    <!-- Delay(millisecond) to show no upstream notification after there's no Backhaul. Set delay to
+         "-1" for disable this feature. -->
+    <integer name="delay_to_show_no_upstream_after_no_backhaul">-1</integer>
+
+    <!-- Cellular roaming notification is shown when upstream is cellular network and in roaming
+         state. -->
+    <!-- Config for showing upstream roaming notification. -->
+    <bool name="config_upstream_roaming_notification">false</bool>
+</resources>
diff --git a/Tethering/res/values/overlayable.xml b/Tethering/res/values/overlayable.xml
new file mode 100644
index 0000000..0ee7a99
--- /dev/null
+++ b/Tethering/res/values/overlayable.xml
@@ -0,0 +1,46 @@
+<?xml version="1.0" encoding="utf-8"?>
+<!-- Copyright (C) 2020 The Android Open Source Project
+
+     Licensed under the Apache License, Version 2.0 (the "License");
+     you may not use this file except in compliance with the License.
+     You may obtain a copy of the License at
+
+          http://www.apache.org/licenses/LICENSE-2.0
+
+     Unless required by applicable law or agreed to in writing, software
+     distributed under the License is distributed on an "AS IS" BASIS,
+     WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+     See the License for the specific language governing permissions and
+     limitations under the License.
+-->
+<resources xmlns:android="http://schemas.android.com/apk/res/android">
+    <overlayable name="TetheringConfig">
+        <policy type="product|system|vendor">
+            <!-- Params from config.xml that can be overlaid -->
+            <item type="array" name="config_tether_usb_regexs"/>
+            <item type="array" name="config_tether_ncm_regexs" />
+            <item type="array" name="config_tether_wifi_regexs"/>
+            <item type="array" name="config_tether_wigig_regexs"/>
+            <item type="array" name="config_tether_wifi_p2p_regexs"/>
+            <item type="array" name="config_tether_bluetooth_regexs"/>
+            <item type="array" name="config_tether_dhcp_range"/>
+            <!-- Use the BPF offload for tethering when the kernel has support. True by default.
+                 If the device doesn't want to support tether BPF offload, this should be false.
+                 Note that this setting could be overridden by device config.
+            -->
+            <item type="bool" name="config_tether_enable_bpf_offload"/>
+            <item type="bool" name="config_tether_enable_legacy_dhcp_server"/>
+            <item type="bool" name="config_tether_enable_legacy_wifi_p2p_dedicated_ip"/>
+            <item type="integer" name="config_tether_offload_poll_interval"/>
+            <item type="array" name="config_tether_upstream_types"/>
+            <item type="bool" name="config_tether_upstream_automatic"/>
+            <!-- Configuration values for tethering entitlement check -->
+            <item type="array" name="config_mobile_hotspot_provision_app"/>
+            <item type="string" name="config_mobile_hotspot_provision_app_no_ui"/>
+            <item type="string" name="config_mobile_hotspot_provision_response"/>
+            <item type="integer" name="config_mobile_hotspot_provision_check_period"/>
+            <item type="string" name="config_wifi_tether_enable"/>
+            <!-- Params from config.xml that can be overlaid -->
+        </policy>
+    </overlayable>
+</resources>
diff --git a/Tethering/res/values/strings.xml b/Tethering/res/values/strings.xml
new file mode 100644
index 0000000..d63c7c5
--- /dev/null
+++ b/Tethering/res/values/strings.xml
@@ -0,0 +1,47 @@
+<?xml version="1.0" encoding="utf-8"?>
+<!-- Copyright (C) 2020 The Android Open Source Project
+
+     Licensed under the Apache License, Version 2.0 (the "License");
+     you may not use this file except in compliance with the License.
+     You may obtain a copy of the License at
+
+          http://www.apache.org/licenses/LICENSE-2.0
+
+     Unless required by applicable law or agreed to in writing, software
+     distributed under the License is distributed on an "AS IS" BASIS,
+     WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+     See the License for the specific language governing permissions and
+     limitations under the License.
+-->
+<resources xmlns:xliff="urn:oasis:names:tc:xliff:document:1.2">
+    <!-- Shown when the device is tethered -->
+    <!-- String for tethered notification title [CHAR LIMIT=200] -->
+    <string name="tethered_notification_title">Tethering or hotspot active</string>
+    <!-- String for tethered notification message [CHAR LIMIT=200] -->
+    <string name="tethered_notification_message">Tap to set up.</string>
+
+    <!-- This notification is shown when tethering has been disabled on a user's device.
+    The device is managed by the user's employer. Tethering can't be turned on unless the
+    IT administrator allows it. The noun "admin" is another reference for "IT administrator." -->
+    <!-- String for tether disabling notification title [CHAR LIMIT=200] -->
+    <string name="disable_tether_notification_title">Tethering is disabled</string>
+    <!-- String for tether disabling notification message [CHAR LIMIT=200] -->
+    <string name="disable_tether_notification_message">Contact your admin for details</string>
+
+    <!-- This string should be consistent with the "Hotspot & tethering" text in the "Network and
+    Internet" settings page. That is currently the tether_settings_title_all string. -->
+    <!-- String for tether notification channel name [CHAR LIMIT=200] -->
+    <string name="notification_channel_tethering_status">Hotspot &amp; tethering status</string>
+
+    <!-- String for no upstream notification title [CHAR LIMIT=200] -->
+    <string name="no_upstream_notification_title"></string>
+    <!-- String for no upstream notification message [CHAR LIMIT=200] -->
+    <string name="no_upstream_notification_message"></string>
+    <!-- String for no upstream notification disable button [CHAR LIMIT=200] -->
+    <string name="no_upstream_notification_disable_button"></string>
+
+    <!-- String for cellular roaming notification title [CHAR LIMIT=200] -->
+    <string name="upstream_roaming_notification_title"></string>
+    <!-- String for cellular roaming notification message [CHAR LIMIT=500] -->
+    <string name="upstream_roaming_notification_message"></string>
+</resources>
diff --git a/Tethering/src/android/net/dhcp/DhcpServerCallbacks.java b/Tethering/src/android/net/dhcp/DhcpServerCallbacks.java
new file mode 100644
index 0000000..9fda125
--- /dev/null
+++ b/Tethering/src/android/net/dhcp/DhcpServerCallbacks.java
@@ -0,0 +1,36 @@
+/*
+ * Copyright (C) 2018 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package android.net.dhcp;
+
+/**
+ * Convenience wrapper around IDhcpServerCallbacks.Stub that implements getInterfaceVersion().
+ * @hide
+ */
+public abstract class DhcpServerCallbacks extends IDhcpServerCallbacks.Stub {
+    /**
+     * Get the version of the aidl interface implemented by the callbacks.
+     */
+    @Override
+    public int getInterfaceVersion() {
+        return IDhcpServerCallbacks.VERSION;
+    }
+
+    @Override
+    public String getInterfaceHash() {
+        return IDhcpServerCallbacks.HASH;
+    }
+}
diff --git a/Tethering/src/android/net/dhcp/DhcpServingParamsParcelExt.java b/Tethering/src/android/net/dhcp/DhcpServingParamsParcelExt.java
new file mode 100644
index 0000000..aaaec17
--- /dev/null
+++ b/Tethering/src/android/net/dhcp/DhcpServingParamsParcelExt.java
@@ -0,0 +1,203 @@
+/*
+ * Copyright (C) 2018 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package android.net.dhcp;
+
+import static com.android.net.module.util.Inet4AddressUtils.inet4AddressToIntHTH;
+
+import android.net.LinkAddress;
+import android.util.ArraySet;
+
+import androidx.annotation.NonNull;
+import androidx.annotation.Nullable;
+
+import java.net.Inet4Address;
+import java.util.Collection;
+import java.util.Collections;
+import java.util.Set;
+
+/**
+ * Subclass of {@link DhcpServingParamsParcel} with additional utility methods for building.
+ *
+ * <p>This utility class does not check for validity of the parameters: invalid parameters are
+ * reported by the receiving module when unparceling the parcel.
+ *
+ * @see DhcpServingParams
+ * @hide
+ */
+public class DhcpServingParamsParcelExt extends DhcpServingParamsParcel {
+    public static final int MTU_UNSET = 0;
+
+    /**
+     * Set the server address and served prefix for the DHCP server.
+     *
+     * <p>This parameter is required.
+     */
+    public DhcpServingParamsParcelExt setServerAddr(@NonNull LinkAddress serverAddr) {
+        this.serverAddr = inet4AddressToIntHTH((Inet4Address) serverAddr.getAddress());
+        this.serverAddrPrefixLength = serverAddr.getPrefixLength();
+        return this;
+    }
+
+    /**
+     * Set the default routers to be advertised to DHCP clients.
+     *
+     * <p>Each router must be inside the served prefix. This may be an empty set, but it must
+     * always be set explicitly.
+     */
+    public DhcpServingParamsParcelExt setDefaultRouters(@NonNull Set<Inet4Address> defaultRouters) {
+        this.defaultRouters = toIntArray(defaultRouters);
+        return this;
+    }
+
+    /**
+     * Set the default routers to be advertised to DHCP clients.
+     *
+     * <p>Each router must be inside the served prefix. This may be an empty list of routers,
+     * but it must always be set explicitly.
+     */
+    public DhcpServingParamsParcelExt setDefaultRouters(@NonNull Inet4Address... defaultRouters) {
+        return setDefaultRouters(newArraySet(defaultRouters));
+    }
+
+    /**
+     * Convenience method to build the parameters with no default router.
+     *
+     * <p>Equivalent to calling {@link #setDefaultRouters(Inet4Address...)} with no address.
+     */
+    public DhcpServingParamsParcelExt setNoDefaultRouter() {
+        return setDefaultRouters();
+    }
+
+    /**
+     * Set the DNS servers to be advertised to DHCP clients.
+     *
+     * <p>This may be an empty set, but it must always be set explicitly.
+     */
+    public DhcpServingParamsParcelExt setDnsServers(@NonNull Set<Inet4Address> dnsServers) {
+        this.dnsServers = toIntArray(dnsServers);
+        return this;
+    }
+
+    /**
+     * Set the DNS servers to be advertised to DHCP clients.
+     *
+     * <p>This may be an empty list of servers, but it must always be set explicitly.
+     */
+    public DhcpServingParamsParcelExt setDnsServers(@NonNull Inet4Address... dnsServers) {
+        return setDnsServers(newArraySet(dnsServers));
+    }
+
+    /**
+     * Convenience method to build the parameters with no DNS server.
+     *
+     * <p>Equivalent to calling {@link #setDnsServers(Inet4Address...)} with no address.
+     */
+    public DhcpServingParamsParcelExt setNoDnsServer() {
+        return setDnsServers();
+    }
+
+    /**
+     * Set excluded addresses that the DHCP server is not allowed to assign to clients.
+     *
+     * <p>This parameter is optional. DNS servers and default routers are always excluded
+     * and do not need to be set here.
+     */
+    public DhcpServingParamsParcelExt setExcludedAddrs(@NonNull Set<Inet4Address> excludedAddrs) {
+        this.excludedAddrs = toIntArray(excludedAddrs);
+        return this;
+    }
+
+    /**
+     * Set excluded addresses that the DHCP server is not allowed to assign to clients.
+     *
+     * <p>This parameter is optional. DNS servers and default routers are always excluded
+     * and do not need to be set here.
+     */
+    public DhcpServingParamsParcelExt setExcludedAddrs(@NonNull Inet4Address... excludedAddrs) {
+        return setExcludedAddrs(newArraySet(excludedAddrs));
+    }
+
+    /**
+     * Set the lease time for leases assigned by the DHCP server.
+     *
+     * <p>This parameter is required.
+     */
+    public DhcpServingParamsParcelExt setDhcpLeaseTimeSecs(long dhcpLeaseTimeSecs) {
+        this.dhcpLeaseTimeSecs = dhcpLeaseTimeSecs;
+        return this;
+    }
+
+    /**
+     * Set the link MTU to be advertised to DHCP clients.
+     *
+     * <p>If set to {@link #MTU_UNSET}, no MTU will be advertised to clients. This parameter
+     * is optional and defaults to {@link #MTU_UNSET}.
+     */
+    public DhcpServingParamsParcelExt setLinkMtu(int linkMtu) {
+        this.linkMtu = linkMtu;
+        return this;
+    }
+
+    /**
+     * Set whether the DHCP server should send the ANDROID_METERED vendor-specific option.
+     *
+     * <p>If not set, the default value is false.
+     */
+    public DhcpServingParamsParcelExt setMetered(boolean metered) {
+        this.metered = metered;
+        return this;
+    }
+
+    /**
+     * Set the client address to tell DHCP server only offer this address.
+     * The client's prefix length is the same as server's.
+     *
+     * <p>If not set, the default value is null.
+     */
+    public DhcpServingParamsParcelExt setSingleClientAddr(@Nullable Inet4Address clientAddr) {
+        this.singleClientAddr = clientAddr == null ? 0 : inet4AddressToIntHTH(clientAddr);
+        return this;
+    }
+
+    /**
+     * Set whether the DHCP server should request a new prefix from IpServer when receiving
+     * DHCPDECLINE message in certain particular link (e.g. there is only one downstream USB
+     * tethering client). If it's false, process DHCPDECLINE message as RFC2131#4.3.3 suggests.
+     *
+     * <p>If not set, the default value is false.
+     */
+    public DhcpServingParamsParcelExt setChangePrefixOnDecline(boolean changePrefixOnDecline) {
+        this.changePrefixOnDecline = changePrefixOnDecline;
+        return this;
+    }
+
+    private static int[] toIntArray(@NonNull Collection<Inet4Address> addrs) {
+        int[] res = new int[addrs.size()];
+        int i = 0;
+        for (Inet4Address addr : addrs) {
+            res[i] = inet4AddressToIntHTH(addr);
+            i++;
+        }
+        return res;
+    }
+
+    private static ArraySet<Inet4Address> newArraySet(Inet4Address... addrs) {
+        ArraySet<Inet4Address> addrSet = new ArraySet<>(addrs.length);
+        Collections.addAll(addrSet, addrs);
+        return addrSet;
+    }
+}
diff --git a/Tethering/src/android/net/ip/DadProxy.java b/Tethering/src/android/net/ip/DadProxy.java
new file mode 100644
index 0000000..e2976b7
--- /dev/null
+++ b/Tethering/src/android/net/ip/DadProxy.java
@@ -0,0 +1,54 @@
+/*
+ * Copyright (C) 2020 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package android.net.ip;
+
+import android.net.util.InterfaceParams;
+import android.os.Handler;
+
+import androidx.annotation.VisibleForTesting;
+
+/**
+ * Basic Duplicate address detection proxy.
+ *
+ * @hide
+ */
+public class DadProxy {
+    private static final String TAG = DadProxy.class.getSimpleName();
+
+    @VisibleForTesting
+    public static NeighborPacketForwarder naForwarder;
+    public static NeighborPacketForwarder nsForwarder;
+
+    public DadProxy(Handler h, InterfaceParams tetheredIface) {
+        naForwarder = new NeighborPacketForwarder(h, tetheredIface,
+                                        NeighborPacketForwarder.ICMPV6_NEIGHBOR_ADVERTISEMENT);
+        nsForwarder = new NeighborPacketForwarder(h, tetheredIface,
+                                        NeighborPacketForwarder.ICMPV6_NEIGHBOR_SOLICITATION);
+    }
+
+    /** Stop NS/NA Forwarders. */
+    public void stop() {
+        naForwarder.stop();
+        nsForwarder.stop();
+    }
+
+    /** Set upstream iface on both forwarders. */
+    public void setUpstreamIface(InterfaceParams upstreamIface) {
+        naForwarder.setUpstreamIface(upstreamIface);
+        nsForwarder.setUpstreamIface(upstreamIface);
+    }
+}
diff --git a/Tethering/src/android/net/ip/IpServer.java b/Tethering/src/android/net/ip/IpServer.java
new file mode 100644
index 0000000..52d59fc
--- /dev/null
+++ b/Tethering/src/android/net/ip/IpServer.java
@@ -0,0 +1,1422 @@
+/*
+ * Copyright (C) 2016 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package android.net.ip;
+
+import static android.net.RouteInfo.RTN_UNICAST;
+import static android.net.TetheringManager.TetheringRequest.checkStaticAddressConfiguration;
+import static android.net.dhcp.IDhcpServer.STATUS_SUCCESS;
+import static android.net.util.NetworkConstants.RFC7421_PREFIX_LENGTH;
+import static android.net.util.NetworkConstants.asByte;
+import static android.net.util.PrefixUtils.asIpPrefix;
+import static android.net.util.TetheringMessageBase.BASE_IPSERVER;
+import static android.system.OsConstants.RT_SCOPE_UNIVERSE;
+
+import static com.android.net.module.util.Inet4AddressUtils.intToInet4AddressHTH;
+
+import android.net.INetd;
+import android.net.INetworkStackStatusCallback;
+import android.net.IpPrefix;
+import android.net.LinkAddress;
+import android.net.LinkProperties;
+import android.net.MacAddress;
+import android.net.RouteInfo;
+import android.net.TetheredClient;
+import android.net.TetheringManager;
+import android.net.TetheringRequestParcel;
+import android.net.dhcp.DhcpLeaseParcelable;
+import android.net.dhcp.DhcpServerCallbacks;
+import android.net.dhcp.DhcpServingParamsParcel;
+import android.net.dhcp.DhcpServingParamsParcelExt;
+import android.net.dhcp.IDhcpEventCallbacks;
+import android.net.dhcp.IDhcpServer;
+import android.net.ip.IpNeighborMonitor.NeighborEvent;
+import android.net.ip.RouterAdvertisementDaemon.RaParams;
+import android.net.shared.NetdUtils;
+import android.net.shared.RouteUtils;
+import android.net.util.InterfaceParams;
+import android.net.util.InterfaceSet;
+import android.net.util.PrefixUtils;
+import android.net.util.SharedLog;
+import android.os.Build;
+import android.os.Handler;
+import android.os.Looper;
+import android.os.Message;
+import android.os.RemoteException;
+import android.os.ServiceSpecificException;
+import android.util.Log;
+import android.util.SparseArray;
+
+import androidx.annotation.NonNull;
+import androidx.annotation.Nullable;
+
+import com.android.internal.util.MessageUtils;
+import com.android.internal.util.State;
+import com.android.internal.util.StateMachine;
+import com.android.networkstack.tethering.BpfCoordinator;
+import com.android.networkstack.tethering.BpfCoordinator.Ipv6ForwardingRule;
+import com.android.networkstack.tethering.PrivateAddressCoordinator;
+
+import java.io.IOException;
+import java.net.Inet4Address;
+import java.net.Inet6Address;
+import java.net.NetworkInterface;
+import java.net.UnknownHostException;
+import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.Collections;
+import java.util.HashSet;
+import java.util.List;
+import java.util.Objects;
+import java.util.Random;
+import java.util.Set;
+
+/**
+ * Provides the interface to IP-layer serving functionality for a given network
+ * interface, e.g. for tethering or "local-only hotspot" mode.
+ *
+ * @hide
+ */
+public class IpServer extends StateMachine {
+    public static final int STATE_UNAVAILABLE = 0;
+    public static final int STATE_AVAILABLE   = 1;
+    public static final int STATE_TETHERED    = 2;
+    public static final int STATE_LOCAL_ONLY  = 3;
+
+    /** Get string name of |state|.*/
+    public static String getStateString(int state) {
+        switch (state) {
+            case STATE_UNAVAILABLE: return "UNAVAILABLE";
+            case STATE_AVAILABLE:   return "AVAILABLE";
+            case STATE_TETHERED:    return "TETHERED";
+            case STATE_LOCAL_ONLY:  return "LOCAL_ONLY";
+        }
+        return "UNKNOWN: " + state;
+    }
+
+    private static final byte DOUG_ADAMS = (byte) 42;
+
+    // TODO: have PanService use some visible version of this constant
+    private static final String BLUETOOTH_IFACE_ADDR = "192.168.44.1/24";
+
+    // TODO: have this configurable
+    private static final int DHCP_LEASE_TIME_SECS = 3600;
+
+    private static final MacAddress NULL_MAC_ADDRESS = MacAddress.fromString("00:00:00:00:00:00");
+
+    private static final String TAG = "IpServer";
+    private static final boolean DBG = false;
+    private static final boolean VDBG = false;
+    private static final Class[] sMessageClasses = {
+            IpServer.class
+    };
+    private static final SparseArray<String> sMagicDecoderRing =
+            MessageUtils.findMessageNames(sMessageClasses);
+
+    /** IpServer callback. */
+    public static class Callback {
+        /**
+         * Notify that |who| has changed its tethering state.
+         *
+         * @param who the calling instance of IpServer
+         * @param state one of STATE_*
+         * @param lastError one of TetheringManager.TETHER_ERROR_*
+         */
+        public void updateInterfaceState(IpServer who, int state, int lastError) { }
+
+        /**
+         * Notify that |who| has new LinkProperties.
+         *
+         * @param who the calling instance of IpServer
+         * @param newLp the new LinkProperties to report
+         */
+        public void updateLinkProperties(IpServer who, LinkProperties newLp) { }
+
+        /**
+         * Notify that the DHCP leases changed in one of the IpServers.
+         */
+        public void dhcpLeasesChanged() { }
+
+        /**
+         * Request Tethering change.
+         *
+         * @param tetheringType the downstream type of this IpServer.
+         * @param enabled enable or disable tethering.
+         */
+        public void requestEnableTethering(int tetheringType, boolean enabled) { }
+    }
+
+    /** Capture IpServer dependencies, for injection. */
+    public abstract static class Dependencies {
+        /**
+         * Create a DadProxy instance to be used by IpServer.
+         * To support multiple tethered interfaces concurrently DAD Proxy
+         * needs to be supported per IpServer instead of per upstream.
+         */
+        public DadProxy getDadProxy(Handler handler, InterfaceParams ifParams) {
+            return new DadProxy(handler, ifParams);
+        }
+
+        /** Create an IpNeighborMonitor to be used by this IpServer */
+        public IpNeighborMonitor getIpNeighborMonitor(Handler handler, SharedLog log,
+                IpNeighborMonitor.NeighborEventConsumer consumer) {
+            return new IpNeighborMonitor(handler, log, consumer);
+        }
+
+        /** Create a RouterAdvertisementDaemon instance to be used by IpServer.*/
+        public RouterAdvertisementDaemon getRouterAdvertisementDaemon(InterfaceParams ifParams) {
+            return new RouterAdvertisementDaemon(ifParams);
+        }
+
+        /** Get |ifName|'s interface information.*/
+        public InterfaceParams getInterfaceParams(String ifName) {
+            return InterfaceParams.getByName(ifName);
+        }
+
+        /** Get |ifName|'s interface index. */
+        public int getIfindex(String ifName) {
+            try {
+                return NetworkInterface.getByName(ifName).getIndex();
+            } catch (IOException | NullPointerException e) {
+                Log.e(TAG, "Can't determine interface index for interface " + ifName);
+                return 0;
+            }
+        }
+
+        /** Create a DhcpServer instance to be used by IpServer. */
+        public abstract void makeDhcpServer(String ifName, DhcpServingParamsParcel params,
+                DhcpServerCallbacks cb);
+    }
+
+    // request from the user that it wants to tether
+    public static final int CMD_TETHER_REQUESTED            = BASE_IPSERVER + 1;
+    // request from the user that it wants to untether
+    public static final int CMD_TETHER_UNREQUESTED          = BASE_IPSERVER + 2;
+    // notification that this interface is down
+    public static final int CMD_INTERFACE_DOWN              = BASE_IPSERVER + 3;
+    // notification from the {@link Tethering.TetherMainSM} that it had trouble enabling IP
+    // Forwarding
+    public static final int CMD_IP_FORWARDING_ENABLE_ERROR  = BASE_IPSERVER + 4;
+    // notification from the {@link Tethering.TetherMainSM} SM that it had trouble disabling IP
+    // Forwarding
+    public static final int CMD_IP_FORWARDING_DISABLE_ERROR = BASE_IPSERVER + 5;
+    // notification from the {@link Tethering.TetherMainSM} SM that it had trouble starting
+    // tethering
+    public static final int CMD_START_TETHERING_ERROR       = BASE_IPSERVER + 6;
+    // notification from the {@link Tethering.TetherMainSM} that it had trouble stopping tethering
+    public static final int CMD_STOP_TETHERING_ERROR        = BASE_IPSERVER + 7;
+    // notification from the {@link Tethering.TetherMainSM} that it had trouble setting the DNS
+    // forwarders
+    public static final int CMD_SET_DNS_FORWARDERS_ERROR    = BASE_IPSERVER + 8;
+    // the upstream connection has changed
+    public static final int CMD_TETHER_CONNECTION_CHANGED   = BASE_IPSERVER + 9;
+    // new IPv6 tethering parameters need to be processed
+    public static final int CMD_IPV6_TETHER_UPDATE          = BASE_IPSERVER + 10;
+    // new neighbor cache entry on our interface
+    public static final int CMD_NEIGHBOR_EVENT              = BASE_IPSERVER + 11;
+    // request from DHCP server that it wants to have a new prefix
+    public static final int CMD_NEW_PREFIX_REQUEST          = BASE_IPSERVER + 12;
+    // request from PrivateAddressCoordinator to restart tethering.
+    public static final int CMD_NOTIFY_PREFIX_CONFLICT      = BASE_IPSERVER + 13;
+
+    private final State mInitialState;
+    private final State mLocalHotspotState;
+    private final State mTetheredState;
+    private final State mUnavailableState;
+    private final State mWaitingForRestartState;
+
+    private final SharedLog mLog;
+    private final INetd mNetd;
+    @NonNull
+    private final BpfCoordinator mBpfCoordinator;
+    private final Callback mCallback;
+    private final InterfaceController mInterfaceCtrl;
+    private final PrivateAddressCoordinator mPrivateAddressCoordinator;
+
+    private final String mIfaceName;
+    private final int mInterfaceType;
+    private final LinkProperties mLinkProperties;
+    private final boolean mUsingLegacyDhcp;
+    private final boolean mUsingBpfOffload;
+
+    private final Dependencies mDeps;
+
+    private int mLastError;
+    private int mServingMode;
+    private InterfaceSet mUpstreamIfaceSet;  // may change over time
+    private InterfaceParams mInterfaceParams;
+    // TODO: De-duplicate this with mLinkProperties above. Currently, these link
+    // properties are those selected by the IPv6TetheringCoordinator and relayed
+    // to us. By comparison, mLinkProperties contains the addresses and directly
+    // connected routes that have been formed from these properties iff. we have
+    // succeeded in configuring them and are able to announce them within Router
+    // Advertisements (otherwise, we do not add them to mLinkProperties at all).
+    private LinkProperties mLastIPv6LinkProperties;
+    private RouterAdvertisementDaemon mRaDaemon;
+    private DadProxy mDadProxy;
+
+    // To be accessed only on the handler thread
+    private int mDhcpServerStartIndex = 0;
+    private IDhcpServer mDhcpServer;
+    private RaParams mLastRaParams;
+
+    private LinkAddress mStaticIpv4ServerAddr;
+    private LinkAddress mStaticIpv4ClientAddr;
+
+    @NonNull
+    private List<TetheredClient> mDhcpLeases = Collections.emptyList();
+
+    private int mLastIPv6UpstreamIfindex = 0;
+
+    private class MyNeighborEventConsumer implements IpNeighborMonitor.NeighborEventConsumer {
+        public void accept(NeighborEvent e) {
+            sendMessage(CMD_NEIGHBOR_EVENT, e);
+        }
+    }
+
+    private final IpNeighborMonitor mIpNeighborMonitor;
+
+    private LinkAddress mIpv4Address;
+
+    // TODO: Add a dependency object to pass the data members or variables from the tethering
+    // object. It helps to reduce the arguments of the constructor.
+    public IpServer(
+            String ifaceName, Looper looper, int interfaceType, SharedLog log,
+            INetd netd, @NonNull BpfCoordinator coordinator, Callback callback,
+            boolean usingLegacyDhcp, boolean usingBpfOffload,
+            PrivateAddressCoordinator addressCoordinator, Dependencies deps) {
+        super(ifaceName, looper);
+        mLog = log.forSubComponent(ifaceName);
+        mNetd = netd;
+        mBpfCoordinator = coordinator;
+        mCallback = callback;
+        mInterfaceCtrl = new InterfaceController(ifaceName, mNetd, mLog);
+        mIfaceName = ifaceName;
+        mInterfaceType = interfaceType;
+        mLinkProperties = new LinkProperties();
+        mUsingLegacyDhcp = usingLegacyDhcp;
+        mUsingBpfOffload = usingBpfOffload;
+        mPrivateAddressCoordinator = addressCoordinator;
+        mDeps = deps;
+        resetLinkProperties();
+        mLastError = TetheringManager.TETHER_ERROR_NO_ERROR;
+        mServingMode = STATE_AVAILABLE;
+
+        mIpNeighborMonitor = mDeps.getIpNeighborMonitor(getHandler(), mLog,
+                new MyNeighborEventConsumer());
+
+        // IP neighbor monitor monitors the neighbor events for adding/removing offload
+        // forwarding rules per client. If BPF offload is not supported, don't start listening
+        // for neighbor events. See updateIpv6ForwardingRules, addIpv6ForwardingRule,
+        // removeIpv6ForwardingRule.
+        if (mUsingBpfOffload && !mIpNeighborMonitor.start()) {
+            mLog.e("Failed to create IpNeighborMonitor on " + mIfaceName);
+        }
+
+        mInitialState = new InitialState();
+        mLocalHotspotState = new LocalHotspotState();
+        mTetheredState = new TetheredState();
+        mUnavailableState = new UnavailableState();
+        mWaitingForRestartState = new WaitingForRestartState();
+        addState(mInitialState);
+        addState(mLocalHotspotState);
+        addState(mTetheredState);
+        addState(mWaitingForRestartState, mTetheredState);
+        addState(mUnavailableState);
+
+        setInitialState(mInitialState);
+    }
+
+    /** Interface name which IpServer served.*/
+    public String interfaceName() {
+        return mIfaceName;
+    }
+
+    /**
+     * Tethering downstream type. It would be one of TetheringManager#TETHERING_*.
+     */
+    public int interfaceType() {
+        return mInterfaceType;
+    }
+
+    /** Last error from this IpServer. */
+    public int lastError() {
+        return mLastError;
+    }
+
+    /** Serving mode is the current state of IpServer state machine. */
+    public int servingMode() {
+        return mServingMode;
+    }
+
+    /** The properties of the network link which IpServer is serving. */
+    public LinkProperties linkProperties() {
+        return new LinkProperties(mLinkProperties);
+    }
+
+    /** The address which IpServer is using. */
+    public LinkAddress getAddress() {
+        return mIpv4Address;
+    }
+
+    /**
+     * Get the latest list of DHCP leases that was reported. Must be called on the IpServer looper
+     * thread.
+     */
+    public List<TetheredClient> getAllLeases() {
+        return Collections.unmodifiableList(mDhcpLeases);
+    }
+
+    /** Stop this IpServer. After this is called this IpServer should not be used any more. */
+    public void stop() {
+        sendMessage(CMD_INTERFACE_DOWN);
+    }
+
+    /**
+     * Tethering is canceled. IpServer state machine will be available and wait for
+     * next tethering request.
+     */
+    public void unwanted() {
+        sendMessage(CMD_TETHER_UNREQUESTED);
+    }
+
+    /** Internals. */
+
+    private boolean startIPv4() {
+        return configureIPv4(true);
+    }
+
+    /**
+     * Convenience wrapper around INetworkStackStatusCallback to run callbacks on the IpServer
+     * handler.
+     *
+     * <p>Different instances of this class can be created for each call to IDhcpServer methods,
+     * with different implementations of the callback, to differentiate handling of success/error in
+     * each call.
+     */
+    private abstract class OnHandlerStatusCallback extends INetworkStackStatusCallback.Stub {
+        @Override
+        public void onStatusAvailable(int statusCode) {
+            getHandler().post(() -> callback(statusCode));
+        }
+
+        public abstract void callback(int statusCode);
+
+        @Override
+        public int getInterfaceVersion() {
+            return this.VERSION;
+        }
+
+        @Override
+        public String getInterfaceHash() {
+            return this.HASH;
+        }
+    }
+
+    private class DhcpServerCallbacksImpl extends DhcpServerCallbacks {
+        private final int mStartIndex;
+
+        private DhcpServerCallbacksImpl(int startIndex) {
+            mStartIndex = startIndex;
+        }
+
+        @Override
+        public void onDhcpServerCreated(int statusCode, IDhcpServer server) throws RemoteException {
+            getHandler().post(() -> {
+                // We are on the handler thread: mDhcpServerStartIndex can be read safely.
+                if (mStartIndex != mDhcpServerStartIndex) {
+                     // This start request is obsolete. Explicitly stop the DHCP server to shut
+                     // down its thread. When the |server| binder token goes out of scope, the
+                     // garbage collector will finalize it, which causes the network stack process
+                     // garbage collector to collect the server itself.
+                    try {
+                        server.stop(null);
+                    } catch (RemoteException e) { }
+                    return;
+                }
+
+                if (statusCode != STATUS_SUCCESS) {
+                    mLog.e("Error obtaining DHCP server: " + statusCode);
+                    handleError();
+                    return;
+                }
+
+                mDhcpServer = server;
+                try {
+                    mDhcpServer.startWithCallbacks(new OnHandlerStatusCallback() {
+                        @Override
+                        public void callback(int startStatusCode) {
+                            if (startStatusCode != STATUS_SUCCESS) {
+                                mLog.e("Error starting DHCP server: " + startStatusCode);
+                                handleError();
+                            }
+                        }
+                    }, new DhcpEventCallback());
+                } catch (RemoteException e) {
+                    throw new IllegalStateException(e);
+                }
+            });
+        }
+
+        private void handleError() {
+            mLastError = TetheringManager.TETHER_ERROR_DHCPSERVER_ERROR;
+            transitionTo(mInitialState);
+        }
+    }
+
+    private class DhcpEventCallback extends IDhcpEventCallbacks.Stub {
+        @Override
+        public void onLeasesChanged(List<DhcpLeaseParcelable> leaseParcelables) {
+            final ArrayList<TetheredClient> leases = new ArrayList<>();
+            for (DhcpLeaseParcelable lease : leaseParcelables) {
+                final LinkAddress address = new LinkAddress(
+                        intToInet4AddressHTH(lease.netAddr), lease.prefixLength,
+                        0 /* flags */, RT_SCOPE_UNIVERSE /* as per RFC6724#3.2 */,
+                        lease.expTime /* deprecationTime */, lease.expTime /* expirationTime */);
+
+                final MacAddress macAddress;
+                try {
+                    macAddress = MacAddress.fromBytes(lease.hwAddr);
+                } catch (IllegalArgumentException e) {
+                    Log.wtf(TAG, "Invalid address received from DhcpServer: "
+                            + Arrays.toString(lease.hwAddr));
+                    return;
+                }
+
+                final TetheredClient.AddressInfo addressInfo = new TetheredClient.AddressInfo(
+                        address, lease.hostname);
+                leases.add(new TetheredClient(
+                        macAddress,
+                        Collections.singletonList(addressInfo),
+                        mInterfaceType));
+            }
+
+            getHandler().post(() -> {
+                mDhcpLeases = leases;
+                mCallback.dhcpLeasesChanged();
+            });
+        }
+
+        @Override
+        public void onNewPrefixRequest(@NonNull final IpPrefix currentPrefix) {
+            Objects.requireNonNull(currentPrefix);
+            sendMessage(CMD_NEW_PREFIX_REQUEST, currentPrefix);
+        }
+
+        @Override
+        public int getInterfaceVersion() {
+            return this.VERSION;
+        }
+
+        @Override
+        public String getInterfaceHash() throws RemoteException {
+            return this.HASH;
+        }
+    }
+
+    private RouteInfo getDirectConnectedRoute(@NonNull final LinkAddress ipv4Address) {
+        Objects.requireNonNull(ipv4Address);
+        return new RouteInfo(PrefixUtils.asIpPrefix(ipv4Address), null, mIfaceName, RTN_UNICAST);
+    }
+
+    private DhcpServingParamsParcel makeServingParams(@NonNull final Inet4Address defaultRouter,
+            @NonNull final Inet4Address dnsServer, @NonNull LinkAddress serverAddr,
+            @Nullable Inet4Address clientAddr) {
+        final boolean changePrefixOnDecline =
+                (mInterfaceType == TetheringManager.TETHERING_NCM && clientAddr == null);
+        return new DhcpServingParamsParcelExt()
+            .setDefaultRouters(defaultRouter)
+            .setDhcpLeaseTimeSecs(DHCP_LEASE_TIME_SECS)
+            .setDnsServers(dnsServer)
+            .setServerAddr(serverAddr)
+            .setMetered(true)
+            .setSingleClientAddr(clientAddr)
+            .setChangePrefixOnDecline(changePrefixOnDecline);
+            // TODO: also advertise link MTU
+    }
+
+    private boolean startDhcp(final LinkAddress serverLinkAddr, final LinkAddress clientLinkAddr) {
+        if (mUsingLegacyDhcp) {
+            return true;
+        }
+
+        final Inet4Address addr = (Inet4Address) serverLinkAddr.getAddress();
+        final Inet4Address clientAddr = clientLinkAddr == null ? null :
+                (Inet4Address) clientLinkAddr.getAddress();
+
+        final DhcpServingParamsParcel params = makeServingParams(addr /* defaultRouter */,
+                addr /* dnsServer */, serverLinkAddr, clientAddr);
+        mDhcpServerStartIndex++;
+        mDeps.makeDhcpServer(
+                mIfaceName, params, new DhcpServerCallbacksImpl(mDhcpServerStartIndex));
+        return true;
+    }
+
+    private void stopDhcp() {
+        // Make all previous start requests obsolete so servers are not started later
+        mDhcpServerStartIndex++;
+
+        if (mDhcpServer != null) {
+            try {
+                mDhcpServer.stop(new OnHandlerStatusCallback() {
+                    @Override
+                    public void callback(int statusCode) {
+                        if (statusCode != STATUS_SUCCESS) {
+                            mLog.e("Error stopping DHCP server: " + statusCode);
+                            mLastError = TetheringManager.TETHER_ERROR_DHCPSERVER_ERROR;
+                            // Not much more we can do here
+                        }
+                        mDhcpLeases.clear();
+                        getHandler().post(mCallback::dhcpLeasesChanged);
+                    }
+                });
+                mDhcpServer = null;
+            } catch (RemoteException e) {
+                mLog.e("Error stopping DHCP server", e);
+                // Not much more we can do here
+            }
+        }
+    }
+
+    private boolean configureDhcp(boolean enable, final LinkAddress serverAddr,
+            final LinkAddress clientAddr) {
+        if (enable) {
+            return startDhcp(serverAddr, clientAddr);
+        } else {
+            stopDhcp();
+            return true;
+        }
+    }
+
+    private void stopIPv4() {
+        configureIPv4(false);
+        // NOTE: All of configureIPv4() will be refactored out of existence
+        // into calls to InterfaceController, shared with startIPv4().
+        mInterfaceCtrl.clearIPv4Address();
+        mPrivateAddressCoordinator.releaseDownstream(this);
+        mIpv4Address = null;
+        mStaticIpv4ServerAddr = null;
+        mStaticIpv4ClientAddr = null;
+    }
+
+    private boolean configureIPv4(boolean enabled) {
+        if (VDBG) Log.d(TAG, "configureIPv4(" + enabled + ")");
+
+        if (enabled) {
+            mIpv4Address = requestIpv4Address(true /* useLastAddress */);
+        }
+
+        if (mIpv4Address == null) {
+            mLog.e("No available ipv4 address");
+            return false;
+        }
+
+        if (mInterfaceType == TetheringManager.TETHERING_BLUETOOTH) {
+            // BT configures the interface elsewhere: only start DHCP.
+            // TODO: make all tethering types behave the same way, and delete the bluetooth
+            // code that calls into NetworkManagementService directly.
+            return configureDhcp(enabled, mIpv4Address, null /* clientAddress */);
+        }
+
+        final IpPrefix ipv4Prefix = asIpPrefix(mIpv4Address);
+
+        final Boolean setIfaceUp;
+        if (mInterfaceType == TetheringManager.TETHERING_WIFI
+                || mInterfaceType == TetheringManager.TETHERING_WIFI_P2P
+                || mInterfaceType == TetheringManager.TETHERING_ETHERNET
+                || mInterfaceType == TetheringManager.TETHERING_WIGIG) {
+            // The WiFi and Ethernet stack has ownership of the interface up/down state.
+            // It is unclear whether the Bluetooth or USB stacks will manage their own
+            // state.
+            setIfaceUp = null;
+        } else {
+            setIfaceUp = enabled;
+        }
+        if (!mInterfaceCtrl.setInterfaceConfiguration(mIpv4Address, setIfaceUp)) {
+            mLog.e("Error configuring interface");
+            if (!enabled) stopDhcp();
+            return false;
+        }
+
+        if (enabled) {
+            mLinkProperties.addLinkAddress(mIpv4Address);
+            mLinkProperties.addRoute(getDirectConnectedRoute(mIpv4Address));
+        } else {
+            mLinkProperties.removeLinkAddress(mIpv4Address);
+            mLinkProperties.removeRoute(getDirectConnectedRoute(mIpv4Address));
+        }
+        return configureDhcp(enabled, mIpv4Address, mStaticIpv4ClientAddr);
+    }
+
+    private LinkAddress requestIpv4Address(final boolean useLastAddress) {
+        if (mStaticIpv4ServerAddr != null) return mStaticIpv4ServerAddr;
+
+        if (mInterfaceType == TetheringManager.TETHERING_BLUETOOTH) {
+            return new LinkAddress(BLUETOOTH_IFACE_ADDR);
+        }
+
+        return mPrivateAddressCoordinator.requestDownstreamAddress(this, useLastAddress);
+    }
+
+    private boolean startIPv6() {
+        mInterfaceParams = mDeps.getInterfaceParams(mIfaceName);
+        if (mInterfaceParams == null) {
+            mLog.e("Failed to find InterfaceParams");
+            stopIPv6();
+            return false;
+        }
+
+        mRaDaemon = mDeps.getRouterAdvertisementDaemon(mInterfaceParams);
+        if (!mRaDaemon.start()) {
+            stopIPv6();
+            return false;
+        }
+
+        // TODO: use ShimUtils instead of explicitly checking the version here.
+        if (Build.VERSION.SDK_INT > Build.VERSION_CODES.R || "S".equals(Build.VERSION.CODENAME)
+                    || "T".equals(Build.VERSION.CODENAME)) {
+            // DAD Proxy starts forwarding packets after IPv6 upstream is present.
+            mDadProxy = mDeps.getDadProxy(getHandler(), mInterfaceParams);
+        }
+
+        return true;
+    }
+
+    private void stopIPv6() {
+        mInterfaceParams = null;
+        setRaParams(null);
+
+        if (mRaDaemon != null) {
+            mRaDaemon.stop();
+            mRaDaemon = null;
+        }
+
+        if (mDadProxy != null) {
+            mDadProxy.stop();
+            mDadProxy = null;
+        }
+    }
+
+    // IPv6TetheringCoordinator sends updates with carefully curated IPv6-only
+    // LinkProperties. These have extraneous data filtered out and only the
+    // necessary prefixes included (per its prefix distribution policy).
+    //
+    // TODO: Evaluate using a data structure than is more directly suited to
+    // communicating only the relevant information.
+    private void updateUpstreamIPv6LinkProperties(LinkProperties v6only, int ttlAdjustment) {
+        if (mRaDaemon == null) return;
+
+        // Avoid unnecessary work on spurious updates.
+        if (Objects.equals(mLastIPv6LinkProperties, v6only)) {
+            return;
+        }
+
+        RaParams params = null;
+        String upstreamIface = null;
+        InterfaceParams upstreamIfaceParams = null;
+        int upstreamIfIndex = 0;
+
+        if (v6only != null) {
+            upstreamIface = v6only.getInterfaceName();
+            upstreamIfaceParams = mDeps.getInterfaceParams(upstreamIface);
+            if (upstreamIfaceParams != null) {
+                upstreamIfIndex = upstreamIfaceParams.index;
+            }
+            params = new RaParams();
+            params.mtu = v6only.getMtu();
+            params.hasDefaultRoute = v6only.hasIpv6DefaultRoute();
+
+            if (params.hasDefaultRoute) params.hopLimit = getHopLimit(upstreamIface, ttlAdjustment);
+
+            for (LinkAddress linkAddr : v6only.getLinkAddresses()) {
+                if (linkAddr.getPrefixLength() != RFC7421_PREFIX_LENGTH) continue;
+
+                final IpPrefix prefix = new IpPrefix(
+                        linkAddr.getAddress(), linkAddr.getPrefixLength());
+                params.prefixes.add(prefix);
+
+                final Inet6Address dnsServer = getLocalDnsIpFor(prefix);
+                if (dnsServer != null) {
+                    params.dnses.add(dnsServer);
+                }
+            }
+
+            // Add upstream index to name mapping for the tether stats usage in the coordinator.
+            // Although this mapping could be added by both class Tethering and IpServer, adding
+            // mapping from IpServer guarantees that the mapping is added before the adding
+            // forwarding rules. That is because there are different state machines in both
+            // classes. It is hard to guarantee the link property update order between multiple
+            // state machines.
+            mBpfCoordinator.addUpstreamNameToLookupTable(upstreamIfIndex, upstreamIface);
+        }
+
+        // If v6only is null, we pass in null to setRaParams(), which handles
+        // deprecation of any existing RA data.
+
+        setRaParams(params);
+        mLastIPv6LinkProperties = v6only;
+
+        updateIpv6ForwardingRules(mLastIPv6UpstreamIfindex, upstreamIfIndex, null);
+        mLastIPv6UpstreamIfindex = upstreamIfIndex;
+        if (mDadProxy != null) {
+            mDadProxy.setUpstreamIface(upstreamIfaceParams);
+        }
+    }
+
+    private void removeRoutesFromLocalNetwork(@NonNull final List<RouteInfo> toBeRemoved) {
+        final int removalFailures = RouteUtils.removeRoutesFromLocalNetwork(
+                mNetd, toBeRemoved);
+        if (removalFailures > 0) {
+            mLog.e(String.format("Failed to remove %d IPv6 routes from local table.",
+                    removalFailures));
+        }
+
+        for (RouteInfo route : toBeRemoved) mLinkProperties.removeRoute(route);
+    }
+
+    private void addRoutesToLocalNetwork(@NonNull final List<RouteInfo> toBeAdded) {
+        try {
+            // It's safe to call networkAddInterface() even if
+            // the interface is already in the local_network.
+            mNetd.networkAddInterface(INetd.LOCAL_NET_ID, mIfaceName);
+            try {
+                // Add routes from local network. Note that adding routes that
+                // already exist does not cause an error (EEXIST is silently ignored).
+                RouteUtils.addRoutesToLocalNetwork(mNetd, mIfaceName, toBeAdded);
+            } catch (IllegalStateException e) {
+                mLog.e("Failed to add IPv4/v6 routes to local table: " + e);
+                return;
+            }
+        } catch (ServiceSpecificException | RemoteException e) {
+            mLog.e("Failed to add " + mIfaceName + " to local table: ", e);
+            return;
+        }
+
+        for (RouteInfo route : toBeAdded) mLinkProperties.addRoute(route);
+    }
+
+    private void configureLocalIPv6Routes(
+            HashSet<IpPrefix> deprecatedPrefixes, HashSet<IpPrefix> newPrefixes) {
+        // [1] Remove the routes that are deprecated.
+        if (!deprecatedPrefixes.isEmpty()) {
+            removeRoutesFromLocalNetwork(getLocalRoutesFor(mIfaceName, deprecatedPrefixes));
+        }
+
+        // [2] Add only the routes that have not previously been added.
+        if (newPrefixes != null && !newPrefixes.isEmpty()) {
+            HashSet<IpPrefix> addedPrefixes = (HashSet) newPrefixes.clone();
+            if (mLastRaParams != null) {
+                addedPrefixes.removeAll(mLastRaParams.prefixes);
+            }
+
+            if (!addedPrefixes.isEmpty()) {
+                addRoutesToLocalNetwork(getLocalRoutesFor(mIfaceName, addedPrefixes));
+            }
+        }
+    }
+
+    private void configureLocalIPv6Dns(
+            HashSet<Inet6Address> deprecatedDnses, HashSet<Inet6Address> newDnses) {
+        // TODO: Is this really necessary? Can we not fail earlier if INetd cannot be located?
+        if (mNetd == null) {
+            if (newDnses != null) newDnses.clear();
+            mLog.e("No netd service instance available; not setting local IPv6 addresses");
+            return;
+        }
+
+        // [1] Remove deprecated local DNS IP addresses.
+        if (!deprecatedDnses.isEmpty()) {
+            for (Inet6Address dns : deprecatedDnses) {
+                if (!mInterfaceCtrl.removeAddress(dns, RFC7421_PREFIX_LENGTH)) {
+                    mLog.e("Failed to remove local dns IP " + dns);
+                }
+
+                mLinkProperties.removeLinkAddress(new LinkAddress(dns, RFC7421_PREFIX_LENGTH));
+            }
+        }
+
+        // [2] Add only the local DNS IP addresses that have not previously been added.
+        if (newDnses != null && !newDnses.isEmpty()) {
+            final HashSet<Inet6Address> addedDnses = (HashSet) newDnses.clone();
+            if (mLastRaParams != null) {
+                addedDnses.removeAll(mLastRaParams.dnses);
+            }
+
+            for (Inet6Address dns : addedDnses) {
+                if (!mInterfaceCtrl.addAddress(dns, RFC7421_PREFIX_LENGTH)) {
+                    mLog.e("Failed to add local dns IP " + dns);
+                    newDnses.remove(dns);
+                }
+
+                mLinkProperties.addLinkAddress(new LinkAddress(dns, RFC7421_PREFIX_LENGTH));
+            }
+        }
+
+        try {
+            mNetd.tetherApplyDnsInterfaces();
+        } catch (ServiceSpecificException | RemoteException e) {
+            mLog.e("Failed to update local DNS caching server");
+            if (newDnses != null) newDnses.clear();
+        }
+    }
+
+    private void addIpv6ForwardingRule(Ipv6ForwardingRule rule) {
+        // Theoretically, we don't need this check because IP neighbor monitor doesn't start if BPF
+        // offload is disabled. Add this check just in case.
+        // TODO: Perhaps remove this protection check.
+        if (!mUsingBpfOffload) return;
+
+        mBpfCoordinator.tetherOffloadRuleAdd(this, rule);
+    }
+
+    private void removeIpv6ForwardingRule(Ipv6ForwardingRule rule) {
+        // TODO: Perhaps remove this protection check.
+        // See the related comment in #addIpv6ForwardingRule.
+        if (!mUsingBpfOffload) return;
+
+        mBpfCoordinator.tetherOffloadRuleRemove(this, rule);
+    }
+
+    private void clearIpv6ForwardingRules() {
+        if (!mUsingBpfOffload) return;
+
+        mBpfCoordinator.tetherOffloadRuleClear(this);
+    }
+
+    private void updateIpv6ForwardingRule(int newIfindex) {
+        // TODO: Perhaps remove this protection check.
+        // See the related comment in #addIpv6ForwardingRule.
+        if (!mUsingBpfOffload) return;
+
+        mBpfCoordinator.tetherOffloadRuleUpdate(this, newIfindex);
+    }
+
+    // Handles all updates to IPv6 forwarding rules. These can currently change only if the upstream
+    // changes or if a neighbor event is received.
+    private void updateIpv6ForwardingRules(int prevUpstreamIfindex, int upstreamIfindex,
+            NeighborEvent e) {
+        // If we no longer have an upstream, clear forwarding rules and do nothing else.
+        if (upstreamIfindex == 0) {
+            clearIpv6ForwardingRules();
+            return;
+        }
+
+        // If the upstream interface has changed, remove all rules and re-add them with the new
+        // upstream interface.
+        if (prevUpstreamIfindex != upstreamIfindex) {
+            updateIpv6ForwardingRule(upstreamIfindex);
+        }
+
+        // If we're here to process a NeighborEvent, do so now.
+        // mInterfaceParams must be non-null or the event would not have arrived.
+        if (e == null) return;
+        if (!(e.ip instanceof Inet6Address) || e.ip.isMulticastAddress()
+                || e.ip.isLoopbackAddress() || e.ip.isLinkLocalAddress()) {
+            return;
+        }
+
+        // When deleting rules, we still need to pass a non-null MAC, even though it's ignored.
+        // Do this here instead of in the Ipv6ForwardingRule constructor to ensure that we never
+        // add rules with a null MAC, only delete them.
+        MacAddress dstMac = e.isValid() ? e.macAddr : NULL_MAC_ADDRESS;
+        Ipv6ForwardingRule rule = new Ipv6ForwardingRule(upstreamIfindex,
+                mInterfaceParams.index, (Inet6Address) e.ip, mInterfaceParams.macAddr, dstMac);
+        if (e.isValid()) {
+            addIpv6ForwardingRule(rule);
+        } else {
+            removeIpv6ForwardingRule(rule);
+        }
+    }
+
+    private void handleNeighborEvent(NeighborEvent e) {
+        if (mInterfaceParams != null
+                && mInterfaceParams.index == e.ifindex
+                && mInterfaceParams.hasMacAddress) {
+            updateIpv6ForwardingRules(mLastIPv6UpstreamIfindex, mLastIPv6UpstreamIfindex, e);
+        }
+    }
+
+    private void handleNewPrefixRequest(@NonNull final IpPrefix currentPrefix) {
+        if (!currentPrefix.contains(mIpv4Address.getAddress())
+                || currentPrefix.getPrefixLength() != mIpv4Address.getPrefixLength()) {
+            Log.e(TAG, "Invalid prefix: " + currentPrefix);
+            return;
+        }
+
+        final LinkAddress deprecatedLinkAddress = mIpv4Address;
+        mIpv4Address = requestIpv4Address(false);
+        if (mIpv4Address == null) {
+            mLog.e("Fail to request a new downstream prefix");
+            return;
+        }
+        final Inet4Address srvAddr = (Inet4Address) mIpv4Address.getAddress();
+
+        // Add new IPv4 address on the interface.
+        if (!mInterfaceCtrl.addAddress(srvAddr, currentPrefix.getPrefixLength())) {
+            mLog.e("Failed to add new IP " + srvAddr);
+            return;
+        }
+
+        // Remove deprecated routes from local network.
+        removeRoutesFromLocalNetwork(
+                Collections.singletonList(getDirectConnectedRoute(deprecatedLinkAddress)));
+        mLinkProperties.removeLinkAddress(deprecatedLinkAddress);
+
+        // Add new routes to local network.
+        addRoutesToLocalNetwork(
+                Collections.singletonList(getDirectConnectedRoute(mIpv4Address)));
+        mLinkProperties.addLinkAddress(mIpv4Address);
+
+        // Update local DNS caching server with new IPv4 address, otherwise, dnsmasq doesn't
+        // listen on the interface configured with new IPv4 address, that results DNS validation
+        // failure of downstream client even if appropriate routes have been configured.
+        try {
+            mNetd.tetherApplyDnsInterfaces();
+        } catch (ServiceSpecificException | RemoteException e) {
+            mLog.e("Failed to update local DNS caching server");
+            return;
+        }
+        sendLinkProperties();
+
+        // Notify DHCP server that new prefix/route has been applied on IpServer.
+        final Inet4Address clientAddr = mStaticIpv4ClientAddr == null ? null :
+                (Inet4Address) mStaticIpv4ClientAddr.getAddress();
+        final DhcpServingParamsParcel params = makeServingParams(srvAddr /* defaultRouter */,
+                srvAddr /* dnsServer */, mIpv4Address /* serverLinkAddress */, clientAddr);
+        try {
+            mDhcpServer.updateParams(params, new OnHandlerStatusCallback() {
+                    @Override
+                    public void callback(int statusCode) {
+                        if (statusCode != STATUS_SUCCESS) {
+                            mLog.e("Error updating DHCP serving params: " + statusCode);
+                        }
+                    }
+            });
+        } catch (RemoteException e) {
+            mLog.e("Error updating DHCP serving params", e);
+        }
+    }
+
+    private byte getHopLimit(String upstreamIface, int adjustTTL) {
+        try {
+            int upstreamHopLimit = Integer.parseUnsignedInt(
+                    mNetd.getProcSysNet(INetd.IPV6, INetd.CONF, upstreamIface, "hop_limit"));
+            upstreamHopLimit = upstreamHopLimit + adjustTTL;
+            // Cap the hop limit to 255.
+            return (byte) Integer.min(upstreamHopLimit, 255);
+        } catch (Exception e) {
+            mLog.e("Failed to find upstream interface hop limit", e);
+        }
+        return RaParams.DEFAULT_HOPLIMIT;
+    }
+
+    private void setRaParams(RaParams newParams) {
+        if (mRaDaemon != null) {
+            final RaParams deprecatedParams =
+                    RaParams.getDeprecatedRaParams(mLastRaParams, newParams);
+
+            configureLocalIPv6Routes(deprecatedParams.prefixes,
+                    (newParams != null) ? newParams.prefixes : null);
+
+            configureLocalIPv6Dns(deprecatedParams.dnses,
+                    (newParams != null) ? newParams.dnses : null);
+
+            mRaDaemon.buildNewRa(deprecatedParams, newParams);
+        }
+
+        mLastRaParams = newParams;
+    }
+
+    private void logMessage(State state, int what) {
+        mLog.log(state.getName() + " got " + sMagicDecoderRing.get(what, Integer.toString(what)));
+    }
+
+    private void sendInterfaceState(int newInterfaceState) {
+        mServingMode = newInterfaceState;
+        mCallback.updateInterfaceState(this, newInterfaceState, mLastError);
+        sendLinkProperties();
+    }
+
+    private void sendLinkProperties() {
+        mCallback.updateLinkProperties(this, new LinkProperties(mLinkProperties));
+    }
+
+    private void resetLinkProperties() {
+        mLinkProperties.clear();
+        mLinkProperties.setInterfaceName(mIfaceName);
+    }
+
+    private void maybeConfigureStaticIp(final TetheringRequestParcel request) {
+        // Ignore static address configuration if they are invalid or null. In theory, static
+        // addresses should not be invalid here because TetheringManager do not allow caller to
+        // specify invalid static address configuration.
+        if (request == null || request.localIPv4Address == null
+                || request.staticClientAddress == null || !checkStaticAddressConfiguration(
+                request.localIPv4Address, request.staticClientAddress)) {
+            return;
+        }
+
+        mStaticIpv4ServerAddr = request.localIPv4Address;
+        mStaticIpv4ClientAddr = request.staticClientAddress;
+    }
+
+    class InitialState extends State {
+        @Override
+        public void enter() {
+            sendInterfaceState(STATE_AVAILABLE);
+        }
+
+        @Override
+        public boolean processMessage(Message message) {
+            logMessage(this, message.what);
+            switch (message.what) {
+                case CMD_TETHER_REQUESTED:
+                    mLastError = TetheringManager.TETHER_ERROR_NO_ERROR;
+                    switch (message.arg1) {
+                        case STATE_LOCAL_ONLY:
+                            maybeConfigureStaticIp((TetheringRequestParcel) message.obj);
+                            transitionTo(mLocalHotspotState);
+                            break;
+                        case STATE_TETHERED:
+                            maybeConfigureStaticIp((TetheringRequestParcel) message.obj);
+                            transitionTo(mTetheredState);
+                            break;
+                        default:
+                            mLog.e("Invalid tethering interface serving state specified.");
+                    }
+                    break;
+                case CMD_INTERFACE_DOWN:
+                    transitionTo(mUnavailableState);
+                    break;
+                case CMD_IPV6_TETHER_UPDATE:
+                    updateUpstreamIPv6LinkProperties((LinkProperties) message.obj, message.arg1);
+                    break;
+                default:
+                    return NOT_HANDLED;
+            }
+            return HANDLED;
+        }
+    }
+
+    class BaseServingState extends State {
+        @Override
+        public void enter() {
+            if (!startIPv4()) {
+                mLastError = TetheringManager.TETHER_ERROR_IFACE_CFG_ERROR;
+                return;
+            }
+
+            try {
+                NetdUtils.tetherInterface(mNetd, mIfaceName, asIpPrefix(mIpv4Address));
+            } catch (RemoteException | ServiceSpecificException | IllegalStateException e) {
+                mLog.e("Error Tethering", e);
+                mLastError = TetheringManager.TETHER_ERROR_TETHER_IFACE_ERROR;
+                return;
+            }
+
+            if (!startIPv6()) {
+                mLog.e("Failed to startIPv6");
+                // TODO: Make this a fatal error once Bluetooth IPv6 is sorted.
+                return;
+            }
+        }
+
+        @Override
+        public void exit() {
+            // Note that at this point, we're leaving the tethered state.  We can fail any
+            // of these operations, but it doesn't really change that we have to try them
+            // all in sequence.
+            stopIPv6();
+
+            try {
+                NetdUtils.untetherInterface(mNetd, mIfaceName);
+            } catch (RemoteException | ServiceSpecificException e) {
+                mLastError = TetheringManager.TETHER_ERROR_UNTETHER_IFACE_ERROR;
+                mLog.e("Failed to untether interface: " + e);
+            }
+
+            stopIPv4();
+
+            resetLinkProperties();
+        }
+
+        @Override
+        public boolean processMessage(Message message) {
+            logMessage(this, message.what);
+            switch (message.what) {
+                case CMD_TETHER_UNREQUESTED:
+                    transitionTo(mInitialState);
+                    if (DBG) Log.d(TAG, "Untethered (unrequested)" + mIfaceName);
+                    break;
+                case CMD_INTERFACE_DOWN:
+                    transitionTo(mUnavailableState);
+                    if (DBG) Log.d(TAG, "Untethered (ifdown)" + mIfaceName);
+                    break;
+                case CMD_IPV6_TETHER_UPDATE:
+                    updateUpstreamIPv6LinkProperties((LinkProperties) message.obj, message.arg1);
+                    sendLinkProperties();
+                    break;
+                case CMD_IP_FORWARDING_ENABLE_ERROR:
+                case CMD_IP_FORWARDING_DISABLE_ERROR:
+                case CMD_START_TETHERING_ERROR:
+                case CMD_STOP_TETHERING_ERROR:
+                case CMD_SET_DNS_FORWARDERS_ERROR:
+                    mLastError = TetheringManager.TETHER_ERROR_INTERNAL_ERROR;
+                    transitionTo(mInitialState);
+                    break;
+                case CMD_NEW_PREFIX_REQUEST:
+                    handleNewPrefixRequest((IpPrefix) message.obj);
+                    break;
+                case CMD_NOTIFY_PREFIX_CONFLICT:
+                    mLog.i("restart tethering: " + mInterfaceType);
+                    mCallback.requestEnableTethering(mInterfaceType, false /* enabled */);
+                    transitionTo(mWaitingForRestartState);
+                    break;
+                default:
+                    return false;
+            }
+            return true;
+        }
+    }
+
+    // Handling errors in BaseServingState.enter() by transitioning is
+    // problematic because transitioning during a multi-state jump yields
+    // a Log.wtf(). Ultimately, there should be only one ServingState,
+    // and forwarding and NAT rules should be handled by a coordinating
+    // functional element outside of IpServer.
+    class LocalHotspotState extends BaseServingState {
+        @Override
+        public void enter() {
+            super.enter();
+            if (mLastError != TetheringManager.TETHER_ERROR_NO_ERROR) {
+                transitionTo(mInitialState);
+            }
+
+            if (DBG) Log.d(TAG, "Local hotspot " + mIfaceName);
+            sendInterfaceState(STATE_LOCAL_ONLY);
+        }
+
+        @Override
+        public boolean processMessage(Message message) {
+            if (super.processMessage(message)) return true;
+
+            logMessage(this, message.what);
+            switch (message.what) {
+                case CMD_TETHER_REQUESTED:
+                    mLog.e("CMD_TETHER_REQUESTED while in local-only hotspot mode.");
+                    break;
+                case CMD_TETHER_CONNECTION_CHANGED:
+                    // Ignored in local hotspot state.
+                    break;
+                default:
+                    return false;
+            }
+            return true;
+        }
+    }
+
+    // Handling errors in BaseServingState.enter() by transitioning is
+    // problematic because transitioning during a multi-state jump yields
+    // a Log.wtf(). Ultimately, there should be only one ServingState,
+    // and forwarding and NAT rules should be handled by a coordinating
+    // functional element outside of IpServer.
+    class TetheredState extends BaseServingState {
+        @Override
+        public void enter() {
+            super.enter();
+            if (mLastError != TetheringManager.TETHER_ERROR_NO_ERROR) {
+                transitionTo(mInitialState);
+            }
+
+            if (DBG) Log.d(TAG, "Tethered " + mIfaceName);
+            sendInterfaceState(STATE_TETHERED);
+        }
+
+        @Override
+        public void exit() {
+            cleanupUpstream();
+            super.exit();
+        }
+
+        private void cleanupUpstream() {
+            if (mUpstreamIfaceSet == null) return;
+
+            for (String ifname : mUpstreamIfaceSet.ifnames) cleanupUpstreamInterface(ifname);
+            mUpstreamIfaceSet = null;
+            clearIpv6ForwardingRules();
+        }
+
+        private void cleanupUpstreamInterface(String upstreamIface) {
+            // Note that we don't care about errors here.
+            // Sometimes interfaces are gone before we get
+            // to remove their rules, which generates errors.
+            // Just do the best we can.
+            try {
+                mNetd.ipfwdRemoveInterfaceForward(mIfaceName, upstreamIface);
+            } catch (RemoteException | ServiceSpecificException e) {
+                mLog.e("Exception in ipfwdRemoveInterfaceForward: " + e.toString());
+            }
+            try {
+                mNetd.tetherRemoveForward(mIfaceName, upstreamIface);
+            } catch (RemoteException | ServiceSpecificException e) {
+                mLog.e("Exception in disableNat: " + e.toString());
+            }
+        }
+
+        @Override
+        public boolean processMessage(Message message) {
+            if (super.processMessage(message)) return true;
+
+            logMessage(this, message.what);
+            switch (message.what) {
+                case CMD_TETHER_REQUESTED:
+                    mLog.e("CMD_TETHER_REQUESTED while already tethering.");
+                    break;
+                case CMD_TETHER_CONNECTION_CHANGED:
+                    final InterfaceSet newUpstreamIfaceSet = (InterfaceSet) message.obj;
+                    if (noChangeInUpstreamIfaceSet(newUpstreamIfaceSet)) {
+                        if (VDBG) Log.d(TAG, "Connection changed noop - dropping");
+                        break;
+                    }
+
+                    if (newUpstreamIfaceSet == null) {
+                        cleanupUpstream();
+                        break;
+                    }
+
+                    for (String removed : upstreamInterfacesRemoved(newUpstreamIfaceSet)) {
+                        cleanupUpstreamInterface(removed);
+                    }
+
+                    final Set<String> added = upstreamInterfacesAdd(newUpstreamIfaceSet);
+                    // This makes the call to cleanupUpstream() in the error
+                    // path for any interface neatly cleanup all the interfaces.
+                    mUpstreamIfaceSet = newUpstreamIfaceSet;
+
+                    for (String ifname : added) {
+                        try {
+                            mNetd.tetherAddForward(mIfaceName, ifname);
+                            mNetd.ipfwdAddInterfaceForward(mIfaceName, ifname);
+                        } catch (RemoteException | ServiceSpecificException e) {
+                            mLog.e("Exception enabling NAT: " + e.toString());
+                            cleanupUpstream();
+                            mLastError = TetheringManager.TETHER_ERROR_ENABLE_FORWARDING_ERROR;
+                            transitionTo(mInitialState);
+                            return true;
+                        }
+                    }
+                    break;
+                case CMD_NEIGHBOR_EVENT:
+                    handleNeighborEvent((NeighborEvent) message.obj);
+                    break;
+                default:
+                    return false;
+            }
+            return true;
+        }
+
+        private boolean noChangeInUpstreamIfaceSet(InterfaceSet newIfaces) {
+            if (mUpstreamIfaceSet == null && newIfaces == null) return true;
+            if (mUpstreamIfaceSet != null && newIfaces != null) {
+                return mUpstreamIfaceSet.equals(newIfaces);
+            }
+            return false;
+        }
+
+        private Set<String> upstreamInterfacesRemoved(InterfaceSet newIfaces) {
+            if (mUpstreamIfaceSet == null) return new HashSet<>();
+
+            final HashSet<String> removed = new HashSet<>(mUpstreamIfaceSet.ifnames);
+            removed.removeAll(newIfaces.ifnames);
+            return removed;
+        }
+
+        private Set<String> upstreamInterfacesAdd(InterfaceSet newIfaces) {
+            final HashSet<String> added = new HashSet<>(newIfaces.ifnames);
+            if (mUpstreamIfaceSet != null) added.removeAll(mUpstreamIfaceSet.ifnames);
+            return added;
+        }
+    }
+
+    /**
+     * This state is terminal for the per interface state machine.  At this
+     * point, the tethering main state machine should have removed this interface
+     * specific state machine from its list of possible recipients of
+     * tethering requests.  The state machine itself will hang around until
+     * the garbage collector finds it.
+     */
+    class UnavailableState extends State {
+        @Override
+        public void enter() {
+            mIpNeighborMonitor.stop();
+            mLastError = TetheringManager.TETHER_ERROR_NO_ERROR;
+            sendInterfaceState(STATE_UNAVAILABLE);
+        }
+    }
+
+    class WaitingForRestartState extends State {
+        @Override
+        public boolean processMessage(Message message) {
+            logMessage(this, message.what);
+            switch (message.what) {
+                case CMD_TETHER_UNREQUESTED:
+                    transitionTo(mInitialState);
+                    mLog.i("Untethered (unrequested) and restarting " + mIfaceName);
+                    mCallback.requestEnableTethering(mInterfaceType, true /* enabled */);
+                    break;
+                case CMD_INTERFACE_DOWN:
+                    transitionTo(mUnavailableState);
+                    mLog.i("Untethered (interface down) and restarting" + mIfaceName);
+                    mCallback.requestEnableTethering(mInterfaceType, true /* enabled */);
+                    break;
+                default:
+                    return false;
+            }
+            return true;
+        }
+    }
+
+    // Accumulate routes representing "prefixes to be assigned to the local
+    // interface", for subsequent modification of local_network routing.
+    private static ArrayList<RouteInfo> getLocalRoutesFor(
+            String ifname, HashSet<IpPrefix> prefixes) {
+        final ArrayList<RouteInfo> localRoutes = new ArrayList<RouteInfo>();
+        for (IpPrefix ipp : prefixes) {
+            localRoutes.add(new RouteInfo(ipp, null, ifname, RTN_UNICAST));
+        }
+        return localRoutes;
+    }
+
+    // Given a prefix like 2001:db8::/64 return an address like 2001:db8::1.
+    private static Inet6Address getLocalDnsIpFor(IpPrefix localPrefix) {
+        final byte[] dnsBytes = localPrefix.getRawAddress();
+        dnsBytes[dnsBytes.length - 1] = getRandomSanitizedByte(DOUG_ADAMS, asByte(0), asByte(1));
+        try {
+            return Inet6Address.getByAddress(null, dnsBytes, 0);
+        } catch (UnknownHostException e) {
+            Log.wtf(TAG, "Failed to construct Inet6Address from: " + localPrefix);
+            return null;
+        }
+    }
+
+    private static byte getRandomSanitizedByte(byte dflt, byte... excluded) {
+        final byte random = (byte) (new Random()).nextInt();
+        for (int value : excluded) {
+            if (random == value) return dflt;
+        }
+        return random;
+    }
+}
diff --git a/Tethering/src/android/net/ip/NeighborPacketForwarder.java b/Tethering/src/android/net/ip/NeighborPacketForwarder.java
new file mode 100644
index 0000000..73fc833
--- /dev/null
+++ b/Tethering/src/android/net/ip/NeighborPacketForwarder.java
@@ -0,0 +1,180 @@
+/*
+ * Copyright (C) 2020 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package android.net.ip;
+
+import static android.system.OsConstants.AF_INET6;
+import static android.system.OsConstants.AF_PACKET;
+import static android.system.OsConstants.ETH_P_IPV6;
+import static android.system.OsConstants.IPPROTO_RAW;
+import static android.system.OsConstants.SOCK_DGRAM;
+import static android.system.OsConstants.SOCK_NONBLOCK;
+import static android.system.OsConstants.SOCK_RAW;
+
+import android.net.util.InterfaceParams;
+import android.net.util.PacketReader;
+import android.net.util.SocketUtils;
+import android.net.util.TetheringUtils;
+import android.os.Handler;
+import android.system.ErrnoException;
+import android.system.Os;
+import android.util.Log;
+
+import java.io.FileDescriptor;
+import java.io.IOException;
+import java.net.Inet6Address;
+import java.net.InetSocketAddress;
+import java.net.SocketAddress;
+import java.net.SocketException;
+import java.net.UnknownHostException;
+import java.util.Arrays;
+
+/**
+ * Basic IPv6 Neighbor Advertisement Forwarder.
+ *
+ * Forward NA packets from upstream iface to tethered iface
+ * and NS packets from tethered iface to upstream iface.
+ *
+ * @hide
+ */
+public class NeighborPacketForwarder extends PacketReader {
+    private final String mTag;
+
+    private FileDescriptor mFd;
+
+    // TODO: get these from NetworkStackConstants.
+    private static final int IPV6_ADDR_LEN = 16;
+    private static final int IPV6_DST_ADDR_OFFSET = 24;
+    private static final int IPV6_HEADER_LEN = 40;
+    private static final int ETH_HEADER_LEN = 14;
+
+    private InterfaceParams mListenIfaceParams, mSendIfaceParams;
+
+    private final int mType;
+    public static final int ICMPV6_NEIGHBOR_ADVERTISEMENT  = 136;
+    public static final int ICMPV6_NEIGHBOR_SOLICITATION = 135;
+
+    public NeighborPacketForwarder(Handler h, InterfaceParams tetheredInterface, int type) {
+        super(h);
+        mTag = NeighborPacketForwarder.class.getSimpleName() + "-"
+                + tetheredInterface.name + "-" + type;
+        mType = type;
+
+        if (mType == ICMPV6_NEIGHBOR_ADVERTISEMENT) {
+            mSendIfaceParams = tetheredInterface;
+        } else {
+            mListenIfaceParams = tetheredInterface;
+        }
+    }
+
+    /** Set new upstream iface and start/stop based on new params. */
+    public void setUpstreamIface(InterfaceParams upstreamParams) {
+        final InterfaceParams oldUpstreamParams;
+
+        if (mType == ICMPV6_NEIGHBOR_ADVERTISEMENT) {
+            oldUpstreamParams = mListenIfaceParams;
+            mListenIfaceParams = upstreamParams;
+        } else {
+            oldUpstreamParams = mSendIfaceParams;
+            mSendIfaceParams = upstreamParams;
+        }
+
+        if (oldUpstreamParams == null && upstreamParams != null) {
+            start();
+        } else if (oldUpstreamParams != null && upstreamParams == null) {
+            stop();
+        } else if (oldUpstreamParams != null && upstreamParams != null
+                   && oldUpstreamParams.index != upstreamParams.index) {
+            stop();
+            start();
+        }
+    }
+
+    // TODO: move NetworkStackUtils.closeSocketQuietly to
+    // frameworks/libs/net/common/device/com/android/net/module/util/[someclass].
+    private void closeSocketQuietly(FileDescriptor fd) {
+        try {
+            SocketUtils.closeSocket(fd);
+        } catch (IOException ignored) {
+        }
+    }
+
+    @Override
+    protected FileDescriptor createFd() {
+        try {
+            // ICMPv6 packets from modem do not have eth header, so RAW socket cannot be used.
+            // To keep uniformity in both directions PACKET socket can be used.
+            mFd = Os.socket(AF_PACKET, SOCK_DGRAM | SOCK_NONBLOCK, 0);
+
+            // TODO: convert setup*Socket to setupICMPv6BpfFilter with filter type?
+            if (mType == ICMPV6_NEIGHBOR_ADVERTISEMENT) {
+                TetheringUtils.setupNaSocket(mFd);
+            } else if (mType == ICMPV6_NEIGHBOR_SOLICITATION) {
+                TetheringUtils.setupNsSocket(mFd);
+            }
+
+            SocketAddress bindAddress = SocketUtils.makePacketSocketAddress(
+                                                        ETH_P_IPV6, mListenIfaceParams.index);
+            Os.bind(mFd, bindAddress);
+        } catch (ErrnoException | SocketException e) {
+            Log.wtf(mTag, "Failed to create  socket", e);
+            closeSocketQuietly(mFd);
+            return null;
+        }
+
+        return mFd;
+    }
+
+    private Inet6Address getIpv6DestinationAddress(byte[] recvbuf) {
+        Inet6Address dstAddr;
+        try {
+            dstAddr = (Inet6Address) Inet6Address.getByAddress(Arrays.copyOfRange(recvbuf,
+                    IPV6_DST_ADDR_OFFSET, IPV6_DST_ADDR_OFFSET + IPV6_ADDR_LEN));
+        } catch (UnknownHostException | ClassCastException impossible) {
+            throw new AssertionError("16-byte array not valid IPv6 address?");
+        }
+        return dstAddr;
+    }
+
+    @Override
+    protected void handlePacket(byte[] recvbuf, int length) {
+        if (mSendIfaceParams == null) {
+            return;
+        }
+
+        // The BPF filter should already have checked the length of the packet, but...
+        if (length < IPV6_HEADER_LEN) {
+            return;
+        }
+        Inet6Address destv6 = getIpv6DestinationAddress(recvbuf);
+        if (!destv6.isMulticastAddress()) {
+            return;
+        }
+        InetSocketAddress dest = new InetSocketAddress(destv6, 0);
+
+        FileDescriptor fd = null;
+        try {
+            fd = Os.socket(AF_INET6, SOCK_RAW | SOCK_NONBLOCK, IPPROTO_RAW);
+            SocketUtils.bindSocketToInterface(fd, mSendIfaceParams.name);
+
+            int ret = Os.sendto(fd, recvbuf, 0, length, 0, dest);
+        } catch (ErrnoException | SocketException e) {
+            Log.e(mTag, "handlePacket error: " + e);
+        } finally {
+            closeSocketQuietly(fd);
+        }
+    }
+}
diff --git a/Tethering/src/android/net/ip/RouterAdvertisementDaemon.java b/Tethering/src/android/net/ip/RouterAdvertisementDaemon.java
new file mode 100644
index 0000000..7c0b7cc
--- /dev/null
+++ b/Tethering/src/android/net/ip/RouterAdvertisementDaemon.java
@@ -0,0 +1,744 @@
+/*
+ * Copyright (C) 2016 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package android.net.ip;
+
+import static android.net.util.NetworkConstants.IPV6_MIN_MTU;
+import static android.net.util.NetworkConstants.RFC7421_PREFIX_LENGTH;
+import static android.net.util.TetheringUtils.getAllNodesForScopeId;
+import static android.system.OsConstants.AF_INET6;
+import static android.system.OsConstants.IPPROTO_ICMPV6;
+import static android.system.OsConstants.SOCK_RAW;
+import static android.system.OsConstants.SOL_SOCKET;
+import static android.system.OsConstants.SO_SNDTIMEO;
+
+import android.net.IpPrefix;
+import android.net.LinkAddress;
+import android.net.TrafficStats;
+import android.net.util.InterfaceParams;
+import android.net.util.SocketUtils;
+import android.net.util.TetheringUtils;
+import android.system.ErrnoException;
+import android.system.Os;
+import android.system.StructTimeval;
+import android.util.Log;
+
+import com.android.internal.annotations.GuardedBy;
+import com.android.internal.util.TrafficStatsConstants;
+
+import java.io.FileDescriptor;
+import java.io.IOException;
+import java.net.Inet6Address;
+import java.net.InetAddress;
+import java.net.InetSocketAddress;
+import java.net.SocketException;
+import java.nio.BufferOverflowException;
+import java.nio.ByteBuffer;
+import java.nio.ByteOrder;
+import java.util.HashMap;
+import java.util.HashSet;
+import java.util.Iterator;
+import java.util.Map;
+import java.util.Random;
+import java.util.Set;
+import java.util.concurrent.atomic.AtomicInteger;
+
+
+/**
+ * Basic IPv6 Router Advertisement Daemon.
+ *
+ * TODO:
+ *
+ *     - Rewrite using Handler (and friends) so that AlarmManager can deliver
+ *       "kick" messages when it's time to send a multicast RA.
+ *
+ * @hide
+ */
+public class RouterAdvertisementDaemon {
+    private static final String TAG = RouterAdvertisementDaemon.class.getSimpleName();
+    private static final byte ICMPV6_ND_ROUTER_SOLICIT = asByte(133);
+    private static final byte ICMPV6_ND_ROUTER_ADVERT  = asByte(134);
+    private static final int MIN_RA_HEADER_SIZE = 16;
+
+    // Summary of various timers and lifetimes.
+    private static final int MIN_RTR_ADV_INTERVAL_SEC = 300;
+    private static final int MAX_RTR_ADV_INTERVAL_SEC = 600;
+    // In general, router, prefix, and DNS lifetimes are all advised to be
+    // greater than or equal to 3 * MAX_RTR_ADV_INTERVAL.  Here, we double
+    // that to allow for multicast packet loss.
+    //
+    // This MAX_RTR_ADV_INTERVAL_SEC and DEFAULT_LIFETIME are also consistent
+    // with the https://tools.ietf.org/html/rfc7772#section-4 discussion of
+    // "approximately 7 RAs per hour".
+    private static final int DEFAULT_LIFETIME = 6 * MAX_RTR_ADV_INTERVAL_SEC;
+    // From https://tools.ietf.org/html/rfc4861#section-10 .
+    private static final int MIN_DELAY_BETWEEN_RAS_SEC = 3;
+    // Both initial and final RAs, but also for changes in RA contents.
+    // From https://tools.ietf.org/html/rfc4861#section-10 .
+    private static final int  MAX_URGENT_RTR_ADVERTISEMENTS = 5;
+
+    private static final int DAY_IN_SECONDS = 86_400;
+
+    private final InterfaceParams mInterface;
+    private final InetSocketAddress mAllNodes;
+
+    // This lock is to protect the RA from being updated while being
+    // transmitted on another thread  (multicast or unicast).
+    //
+    // TODO: This should be handled with a more RCU-like approach.
+    private final Object mLock = new Object();
+    @GuardedBy("mLock")
+    private final byte[] mRA = new byte[IPV6_MIN_MTU];
+    @GuardedBy("mLock")
+    private int mRaLength;
+    @GuardedBy("mLock")
+    private final DeprecatedInfoTracker mDeprecatedInfoTracker;
+    @GuardedBy("mLock")
+    private RaParams mRaParams;
+
+    private volatile FileDescriptor mSocket;
+    private volatile MulticastTransmitter mMulticastTransmitter;
+    private volatile UnicastResponder mUnicastResponder;
+
+    /** Encapsulate the RA parameters for RouterAdvertisementDaemon.*/
+    public static class RaParams {
+        // Tethered traffic will have the hop limit properly decremented.
+        // Consequently, set the hoplimit greater by one than the upstream
+        // unicast hop limit.
+        //
+        // TODO: Dynamically pass down the IPV6_UNICAST_HOPS value from the
+        // upstream interface for more correct behaviour.
+        static final byte DEFAULT_HOPLIMIT = 65;
+
+        public boolean hasDefaultRoute;
+        public byte hopLimit;
+        public int mtu;
+        public HashSet<IpPrefix> prefixes;
+        public HashSet<Inet6Address> dnses;
+
+        public RaParams() {
+            hasDefaultRoute = false;
+            hopLimit = DEFAULT_HOPLIMIT;
+            mtu = IPV6_MIN_MTU;
+            prefixes = new HashSet<IpPrefix>();
+            dnses = new HashSet<Inet6Address>();
+        }
+
+        public RaParams(RaParams other) {
+            hasDefaultRoute = other.hasDefaultRoute;
+            hopLimit = other.hopLimit;
+            mtu = other.mtu;
+            prefixes = (HashSet) other.prefixes.clone();
+            dnses = (HashSet) other.dnses.clone();
+        }
+
+        /**
+         * Returns the subset of RA parameters that become deprecated when
+         * moving from announcing oldRa to announcing newRa.
+         *
+         * Currently only tracks differences in |prefixes| and |dnses|.
+         */
+        public static RaParams getDeprecatedRaParams(RaParams oldRa, RaParams newRa) {
+            RaParams newlyDeprecated = new RaParams();
+
+            if (oldRa != null) {
+                for (IpPrefix ipp : oldRa.prefixes) {
+                    if (newRa == null || !newRa.prefixes.contains(ipp)) {
+                        newlyDeprecated.prefixes.add(ipp);
+                    }
+                }
+
+                for (Inet6Address dns : oldRa.dnses) {
+                    if (newRa == null || !newRa.dnses.contains(dns)) {
+                        newlyDeprecated.dnses.add(dns);
+                    }
+                }
+            }
+
+            return newlyDeprecated;
+        }
+    }
+
+    private static class DeprecatedInfoTracker {
+        private final HashMap<IpPrefix, Integer> mPrefixes = new HashMap<>();
+        private final HashMap<Inet6Address, Integer> mDnses = new HashMap<>();
+
+        Set<IpPrefix> getPrefixes() {
+            return mPrefixes.keySet();
+        }
+
+        void putPrefixes(Set<IpPrefix> prefixes) {
+            for (IpPrefix ipp : prefixes) {
+                mPrefixes.put(ipp, MAX_URGENT_RTR_ADVERTISEMENTS);
+            }
+        }
+
+        void removePrefixes(Set<IpPrefix> prefixes) {
+            for (IpPrefix ipp : prefixes) {
+                mPrefixes.remove(ipp);
+            }
+        }
+
+        Set<Inet6Address> getDnses() {
+            return mDnses.keySet();
+        }
+
+        void putDnses(Set<Inet6Address> dnses) {
+            for (Inet6Address dns : dnses) {
+                mDnses.put(dns, MAX_URGENT_RTR_ADVERTISEMENTS);
+            }
+        }
+
+        void removeDnses(Set<Inet6Address> dnses) {
+            for (Inet6Address dns : dnses) {
+                mDnses.remove(dns);
+            }
+        }
+
+        boolean isEmpty() {
+            return mPrefixes.isEmpty() && mDnses.isEmpty();
+        }
+
+        private boolean decrementCounters() {
+            boolean removed = decrementCounter(mPrefixes);
+            removed |= decrementCounter(mDnses);
+            return removed;
+        }
+
+        private <T> boolean decrementCounter(HashMap<T, Integer> map) {
+            boolean removed = false;
+
+            for (Iterator<Map.Entry<T, Integer>> it = map.entrySet().iterator();
+                    it.hasNext();) {
+                Map.Entry<T, Integer> kv = it.next();
+                if (kv.getValue() == 0) {
+                    it.remove();
+                    removed = true;
+                } else {
+                    kv.setValue(kv.getValue() - 1);
+                }
+            }
+
+            return removed;
+        }
+    }
+
+    public RouterAdvertisementDaemon(InterfaceParams ifParams) {
+        mInterface = ifParams;
+        mAllNodes = new InetSocketAddress(getAllNodesForScopeId(mInterface.index), 0);
+        mDeprecatedInfoTracker = new DeprecatedInfoTracker();
+    }
+
+    /** Build new RA.*/
+    public void buildNewRa(RaParams deprecatedParams, RaParams newParams) {
+        synchronized (mLock) {
+            if (deprecatedParams != null) {
+                mDeprecatedInfoTracker.putPrefixes(deprecatedParams.prefixes);
+                mDeprecatedInfoTracker.putDnses(deprecatedParams.dnses);
+            }
+
+            if (newParams != null) {
+                // Process information that is no longer deprecated.
+                mDeprecatedInfoTracker.removePrefixes(newParams.prefixes);
+                mDeprecatedInfoTracker.removeDnses(newParams.dnses);
+            }
+
+            mRaParams = newParams;
+            assembleRaLocked();
+        }
+
+        maybeNotifyMulticastTransmitter();
+    }
+
+    /** Start router advertisement daemon. */
+    public boolean start() {
+        if (!createSocket()) {
+            return false;
+        }
+
+        mMulticastTransmitter = new MulticastTransmitter();
+        mMulticastTransmitter.start();
+
+        mUnicastResponder = new UnicastResponder();
+        mUnicastResponder.start();
+
+        return true;
+    }
+
+    /** Stop router advertisement daemon. */
+    public void stop() {
+        closeSocket();
+        // Wake up mMulticastTransmitter thread to interrupt a potential 1 day sleep before
+        // the thread's termination.
+        maybeNotifyMulticastTransmitter();
+        mMulticastTransmitter = null;
+        mUnicastResponder = null;
+    }
+
+    @GuardedBy("mLock")
+    private void assembleRaLocked() {
+        final ByteBuffer ra = ByteBuffer.wrap(mRA);
+        ra.order(ByteOrder.BIG_ENDIAN);
+
+        final boolean haveRaParams = (mRaParams != null);
+        boolean shouldSendRA = false;
+
+        try {
+            putHeader(ra, haveRaParams && mRaParams.hasDefaultRoute,
+                    haveRaParams ? mRaParams.hopLimit : RaParams.DEFAULT_HOPLIMIT);
+            putSlla(ra, mInterface.macAddr.toByteArray());
+            mRaLength = ra.position();
+
+            // https://tools.ietf.org/html/rfc5175#section-4 says:
+            //
+            //     "MUST NOT be added to a Router Advertisement message
+            //      if no flags in the option are set."
+            //
+            // putExpandedFlagsOption(ra);
+
+            if (haveRaParams) {
+                putMtu(ra, mRaParams.mtu);
+                mRaLength = ra.position();
+
+                for (IpPrefix ipp : mRaParams.prefixes) {
+                    putPio(ra, ipp, DEFAULT_LIFETIME, DEFAULT_LIFETIME);
+                    mRaLength = ra.position();
+                    shouldSendRA = true;
+                }
+
+                if (mRaParams.dnses.size() > 0) {
+                    putRdnss(ra, mRaParams.dnses, DEFAULT_LIFETIME);
+                    mRaLength = ra.position();
+                    shouldSendRA = true;
+                }
+            }
+
+            for (IpPrefix ipp : mDeprecatedInfoTracker.getPrefixes()) {
+                putPio(ra, ipp, 0, 0);
+                mRaLength = ra.position();
+                shouldSendRA = true;
+            }
+
+            final Set<Inet6Address> deprecatedDnses = mDeprecatedInfoTracker.getDnses();
+            if (!deprecatedDnses.isEmpty()) {
+                putRdnss(ra, deprecatedDnses, 0);
+                mRaLength = ra.position();
+                shouldSendRA = true;
+            }
+        } catch (BufferOverflowException e) {
+            // The packet up to mRaLength  is valid, since it has been updated
+            // progressively as the RA was built. Log an error, and continue
+            // on as best as possible.
+            Log.e(TAG, "Could not construct new RA: " + e);
+        }
+
+        // We have nothing worth announcing; indicate as much to maybeSendRA().
+        if (!shouldSendRA) {
+            mRaLength = 0;
+        }
+    }
+
+    private void maybeNotifyMulticastTransmitter() {
+        final MulticastTransmitter m = mMulticastTransmitter;
+        if (m != null) {
+            m.hup();
+        }
+    }
+
+    private static byte asByte(int value) {
+        return (byte) value;
+    }
+    private static short asShort(int value) {
+        return (short) value;
+    }
+
+    private static void putHeader(ByteBuffer ra, boolean hasDefaultRoute, byte hopLimit) {
+        /**
+            Router Advertisement Message Format
+
+             0                   1                   2                   3
+             0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+            +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+            |     Type      |     Code      |          Checksum             |
+            +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+            | Cur Hop Limit |M|O|H|Prf|P|R|R|       Router Lifetime         |
+            +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+            |                         Reachable Time                        |
+            +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+            |                          Retrans Timer                        |
+            +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+            |   Options ...
+            +-+-+-+-+-+-+-+-+-+-+-+-
+        */
+        ra.put(ICMPV6_ND_ROUTER_ADVERT)
+                .put(asByte(0))
+                .putShort(asShort(0))
+                .put(hopLimit)
+                // RFC 4191 "high" preference, iff. advertising a default route.
+                .put(hasDefaultRoute ? asByte(0x08) : asByte(0))
+                .putShort(hasDefaultRoute ? asShort(DEFAULT_LIFETIME) : asShort(0))
+                .putInt(0)
+                .putInt(0);
+    }
+
+    private static void putSlla(ByteBuffer ra, byte[] slla) {
+        /**
+            Source/Target Link-layer Address
+
+             0                   1                   2                   3
+             0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+            +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+            |     Type      |    Length     |    Link-Layer Address ...
+            +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+        */
+        if (slla == null || slla.length != 6) {
+            // Only IEEE 802.3 6-byte addresses are supported.
+            return;
+        }
+
+        final byte nd_option_slla = 1;
+        final byte slla_num_8octets = 1;
+        ra.put(nd_option_slla)
+            .put(slla_num_8octets)
+            .put(slla);
+    }
+
+    private static void putExpandedFlagsOption(ByteBuffer ra) {
+        /**
+            Router Advertisement Expanded Flags Option
+
+             0                   1                   2                   3
+             0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+            +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+            |     Type      |    Length     |         Bit fields available ..
+            +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+            ... for assignment                                              |
+            +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+         */
+
+        final byte nd_option__efo = 26;
+        final byte efo_num_8octets = 1;
+
+        ra.put(nd_option__efo)
+            .put(efo_num_8octets)
+            .putShort(asShort(0))
+            .putInt(0);
+    }
+
+    private static void putMtu(ByteBuffer ra, int mtu) {
+        /**
+            MTU
+
+             0                   1                   2                   3
+             0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+            +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+            |     Type      |    Length     |           Reserved            |
+            +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+            |                              MTU                              |
+            +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+        */
+        final byte nd_option_mtu = 5;
+        final byte mtu_num_8octs = 1;
+        ra.put(nd_option_mtu)
+            .put(mtu_num_8octs)
+            .putShort(asShort(0))
+            .putInt((mtu < IPV6_MIN_MTU) ? IPV6_MIN_MTU : mtu);
+    }
+
+    private static void putPio(ByteBuffer ra, IpPrefix ipp,
+                               int validTime, int preferredTime) {
+        /**
+            Prefix Information
+
+             0                   1                   2                   3
+             0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+            +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+            |     Type      |    Length     | Prefix Length |L|A| Reserved1 |
+            +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+            |                         Valid Lifetime                        |
+            +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+            |                       Preferred Lifetime                      |
+            +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+            |                           Reserved2                           |
+            +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+            |                                                               |
+            +                                                               +
+            |                                                               |
+            +                            Prefix                             +
+            |                                                               |
+            +                                                               +
+            |                                                               |
+            +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+        */
+        final int prefixLength = ipp.getPrefixLength();
+        if (prefixLength != 64) {
+            return;
+        }
+        final byte nd_option_pio = 3;
+        final byte pio_num_8octets = 4;
+
+        if (validTime < 0) validTime = 0;
+        if (preferredTime < 0) preferredTime = 0;
+        if (preferredTime > validTime) preferredTime = validTime;
+
+        final byte[] addr = ipp.getAddress().getAddress();
+        ra.put(nd_option_pio)
+            .put(pio_num_8octets)
+            .put(asByte(prefixLength))
+            .put(asByte(0xc0)) /* L & A set */
+            .putInt(validTime)
+            .putInt(preferredTime)
+            .putInt(0)
+            .put(addr);
+    }
+
+    private static void putRio(ByteBuffer ra, IpPrefix ipp) {
+        /**
+            Route Information Option
+
+             0                   1                   2                   3
+             0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+            +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+            |     Type      |    Length     | Prefix Length |Resvd|Prf|Resvd|
+            +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+            |                        Route Lifetime                         |
+            +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+            |                   Prefix (Variable Length)                    |
+            .                                                               .
+            .                                                               .
+            +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+         */
+        final int prefixLength = ipp.getPrefixLength();
+        if (prefixLength > 64) {
+            return;
+        }
+        final byte nd_option_rio = 24;
+        final byte rio_num_8octets = asByte(
+                (prefixLength == 0) ? 1 : (prefixLength <= 8) ? 2 : 3);
+
+        final byte[] addr = ipp.getAddress().getAddress();
+        ra.put(nd_option_rio)
+            .put(rio_num_8octets)
+            .put(asByte(prefixLength))
+            .put(asByte(0x18))
+            .putInt(DEFAULT_LIFETIME);
+
+        // Rely upon an IpPrefix's address being properly zeroed.
+        if (prefixLength > 0) {
+            ra.put(addr, 0, (prefixLength <= 64) ? 8 : 16);
+        }
+    }
+
+    private static void putRdnss(ByteBuffer ra, Set<Inet6Address> dnses, int lifetime) {
+        /**
+            Recursive DNS Server (RDNSS) Option
+
+             0                   1                   2                   3
+             0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+            +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+            |     Type      |     Length    |           Reserved            |
+            +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+            |                           Lifetime                            |
+            +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+            |                                                               |
+            :            Addresses of IPv6 Recursive DNS Servers            :
+            |                                                               |
+            +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+         */
+
+        final HashSet<Inet6Address> filteredDnses = new HashSet<>();
+        for (Inet6Address dns : dnses) {
+            if ((new LinkAddress(dns, RFC7421_PREFIX_LENGTH)).isGlobalPreferred()) {
+                filteredDnses.add(dns);
+            }
+        }
+        if (filteredDnses.isEmpty()) return;
+
+        final byte nd_option_rdnss = 25;
+        final byte rdnss_num_8octets = asByte(dnses.size() * 2 + 1);
+        ra.put(nd_option_rdnss)
+            .put(rdnss_num_8octets)
+            .putShort(asShort(0))
+            .putInt(lifetime);
+
+        for (Inet6Address dns : filteredDnses) {
+            // NOTE: If the full of list DNS servers doesn't fit in the packet,
+            // this code will cause a buffer overflow and the RA won't include
+            // this instance of the option at all.
+            //
+            // TODO: Consider looking at ra.remaining() to determine how many
+            // DNS servers will fit, and adding only those.
+            ra.put(dns.getAddress());
+        }
+    }
+
+    private boolean createSocket() {
+        final int send_timout_ms = 300;
+
+        final int oldTag = TrafficStats.getAndSetThreadStatsTag(
+                TrafficStatsConstants.TAG_SYSTEM_NEIGHBOR);
+        try {
+            mSocket = Os.socket(AF_INET6, SOCK_RAW, IPPROTO_ICMPV6);
+            // Setting SNDTIMEO is purely for defensive purposes.
+            Os.setsockoptTimeval(
+                    mSocket, SOL_SOCKET, SO_SNDTIMEO, StructTimeval.fromMillis(send_timout_ms));
+            SocketUtils.bindSocketToInterface(mSocket, mInterface.name);
+            TetheringUtils.setupRaSocket(mSocket, mInterface.index);
+        } catch (ErrnoException | IOException e) {
+            Log.e(TAG, "Failed to create RA daemon socket: " + e);
+            return false;
+        } finally {
+            TrafficStats.setThreadStatsTag(oldTag);
+        }
+
+        return true;
+    }
+
+    private void closeSocket() {
+        if (mSocket != null) {
+            try {
+                SocketUtils.closeSocket(mSocket);
+            } catch (IOException ignored) { }
+        }
+        mSocket = null;
+    }
+
+    private boolean isSocketValid() {
+        final FileDescriptor s = mSocket;
+        return (s != null) && s.valid();
+    }
+
+    private boolean isSuitableDestination(InetSocketAddress dest) {
+        if (mAllNodes.equals(dest)) {
+            return true;
+        }
+
+        final InetAddress destip = dest.getAddress();
+        return (destip instanceof Inet6Address)
+               && destip.isLinkLocalAddress()
+               && (((Inet6Address) destip).getScopeId() == mInterface.index);
+    }
+
+    private void maybeSendRA(InetSocketAddress dest) {
+        if (dest == null || !isSuitableDestination(dest)) {
+            dest = mAllNodes;
+        }
+
+        try {
+            synchronized (mLock) {
+                if (mRaLength < MIN_RA_HEADER_SIZE) {
+                    // No actual RA to send.
+                    return;
+                }
+                Os.sendto(mSocket, mRA, 0, mRaLength, 0, dest);
+            }
+            Log.d(TAG, "RA sendto " + dest.getAddress().getHostAddress());
+        } catch (ErrnoException | SocketException e) {
+            if (isSocketValid()) {
+                Log.e(TAG, "sendto error: " + e);
+            }
+        }
+    }
+
+    private final class UnicastResponder extends Thread {
+        private final InetSocketAddress mSolicitor = new InetSocketAddress(0);
+        // The recycled buffer for receiving Router Solicitations from clients.
+        // If the RS is larger than IPV6_MIN_MTU the packets are truncated.
+        // This is fine since currently only byte 0 is examined anyway.
+        private final byte[] mSolicitation = new byte[IPV6_MIN_MTU];
+
+        @Override
+        public void run() {
+            while (isSocketValid()) {
+                try {
+                    // Blocking receive.
+                    final int rval = Os.recvfrom(
+                            mSocket, mSolicitation, 0, mSolicitation.length, 0, mSolicitor);
+                    // Do the least possible amount of validation.
+                    if (rval < 1 || mSolicitation[0] != ICMPV6_ND_ROUTER_SOLICIT) {
+                        continue;
+                    }
+                } catch (ErrnoException | SocketException e) {
+                    if (isSocketValid()) {
+                        Log.e(TAG, "recvfrom error: " + e);
+                    }
+                    continue;
+                }
+
+                maybeSendRA(mSolicitor);
+            }
+        }
+    }
+
+    // TODO: Consider moving this to run on a provided Looper as a Handler,
+    // with WakeupMessage-style messages providing the timer driven input.
+    private final class MulticastTransmitter extends Thread {
+        private final Random mRandom = new Random();
+        private final AtomicInteger mUrgentAnnouncements = new AtomicInteger(0);
+
+        @Override
+        public void run() {
+            while (isSocketValid()) {
+                try {
+                    Thread.sleep(getNextMulticastTransmitDelayMs());
+                } catch (InterruptedException ignored) {
+                    // Stop sleeping, immediately send an RA, and continue.
+                }
+
+                maybeSendRA(mAllNodes);
+                synchronized (mLock) {
+                    if (mDeprecatedInfoTracker.decrementCounters()) {
+                        // At least one deprecated PIO has been removed;
+                        // reassemble the RA.
+                        assembleRaLocked();
+                    }
+                }
+            }
+        }
+
+        public void hup() {
+            // Set to one fewer that the desired number, because as soon as
+            // the thread interrupt is processed we immediately send an RA
+            // and mUrgentAnnouncements is not examined until the subsequent
+            // sleep interval computation (i.e. this way we send 3 and not 4).
+            mUrgentAnnouncements.set(MAX_URGENT_RTR_ADVERTISEMENTS - 1);
+            interrupt();
+        }
+
+        private int getNextMulticastTransmitDelaySec() {
+            boolean deprecationInProgress = false;
+            synchronized (mLock) {
+                if (mRaLength < MIN_RA_HEADER_SIZE) {
+                    // No actual RA to send; just sleep for 1 day.
+                    return DAY_IN_SECONDS;
+                }
+                deprecationInProgress = !mDeprecatedInfoTracker.isEmpty();
+            }
+
+            final int urgentPending = mUrgentAnnouncements.getAndDecrement();
+            if ((urgentPending > 0) || deprecationInProgress) {
+                return MIN_DELAY_BETWEEN_RAS_SEC;
+            }
+
+            return MIN_RTR_ADV_INTERVAL_SEC + mRandom.nextInt(
+                    MAX_RTR_ADV_INTERVAL_SEC - MIN_RTR_ADV_INTERVAL_SEC);
+        }
+
+        private long getNextMulticastTransmitDelayMs() {
+            return 1000 * (long) getNextMulticastTransmitDelaySec();
+        }
+    }
+}
diff --git a/Tethering/src/android/net/util/BaseNetdUnsolicitedEventListener.java b/Tethering/src/android/net/util/BaseNetdUnsolicitedEventListener.java
new file mode 100644
index 0000000..b1ffdb0
--- /dev/null
+++ b/Tethering/src/android/net/util/BaseNetdUnsolicitedEventListener.java
@@ -0,0 +1,75 @@
+/*
+ * Copyright (C) 2019 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package android.net.util;
+
+import android.net.INetdUnsolicitedEventListener;
+
+import androidx.annotation.NonNull;
+
+/**
+ * Base {@link INetdUnsolicitedEventListener} that provides no-op implementations which can be
+ * overridden.
+ */
+public class BaseNetdUnsolicitedEventListener extends INetdUnsolicitedEventListener.Stub {
+
+    @Override
+    public void onInterfaceClassActivityChanged(boolean isActive, int timerLabel, long timestampNs,
+            int uid) { }
+
+    @Override
+    public void onQuotaLimitReached(@NonNull String alertName, @NonNull String ifName) { }
+
+    @Override
+    public void onInterfaceDnsServerInfo(@NonNull String ifName, long lifetimeS,
+            @NonNull String[] servers) { }
+
+    @Override
+    public void onInterfaceAddressUpdated(@NonNull String addr, String ifName, int flags,
+            int scope) { }
+
+    @Override
+    public void onInterfaceAddressRemoved(@NonNull String addr, @NonNull String ifName, int flags,
+            int scope) { }
+
+    @Override
+    public void onInterfaceAdded(@NonNull String ifName) { }
+
+    @Override
+    public void onInterfaceRemoved(@NonNull String ifName) { }
+
+    @Override
+    public void onInterfaceChanged(@NonNull String ifName, boolean up) { }
+
+    @Override
+    public void onInterfaceLinkStateChanged(@NonNull String ifName, boolean up) { }
+
+    @Override
+    public void onRouteChanged(boolean updated, @NonNull String route, @NonNull String gateway,
+            @NonNull String ifName) { }
+
+    @Override
+    public void onStrictCleartextDetected(int uid, @NonNull String hex) { }
+
+    @Override
+    public int getInterfaceVersion() {
+        return INetdUnsolicitedEventListener.VERSION;
+    }
+
+    @Override
+    public String getInterfaceHash() {
+        return INetdUnsolicitedEventListener.HASH;
+    }
+}
diff --git a/Tethering/src/android/net/util/InterfaceSet.java b/Tethering/src/android/net/util/InterfaceSet.java
new file mode 100644
index 0000000..7589787
--- /dev/null
+++ b/Tethering/src/android/net/util/InterfaceSet.java
@@ -0,0 +1,52 @@
+/*
+ * Copyright (C) 2018 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package android.net.util;
+
+import java.util.Collections;
+import java.util.HashSet;
+import java.util.Set;
+import java.util.StringJoiner;
+
+
+/**
+ * @hide
+ */
+public class InterfaceSet {
+    public final Set<String> ifnames;
+
+    public InterfaceSet(String... names) {
+        final Set<String> nameSet = new HashSet<>();
+        for (String name : names) {
+            if (name != null) nameSet.add(name);
+        }
+        ifnames = Collections.unmodifiableSet(nameSet);
+    }
+
+    @Override
+    public String toString() {
+        final StringJoiner sj = new StringJoiner(",", "[", "]");
+        for (String ifname : ifnames) sj.add(ifname);
+        return sj.toString();
+    }
+
+    @Override
+    public boolean equals(Object obj) {
+        return obj != null
+                && obj instanceof InterfaceSet
+                && ifnames.equals(((InterfaceSet) obj).ifnames);
+    }
+}
diff --git a/Tethering/src/android/net/util/PrefixUtils.java b/Tethering/src/android/net/util/PrefixUtils.java
new file mode 100644
index 0000000..f203e99
--- /dev/null
+++ b/Tethering/src/android/net/util/PrefixUtils.java
@@ -0,0 +1,88 @@
+/*
+ * Copyright (C) 2017 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package android.net.util;
+
+import android.net.IpPrefix;
+import android.net.LinkAddress;
+import android.net.LinkProperties;
+
+import java.net.Inet4Address;
+import java.net.InetAddress;
+import java.util.Collections;
+import java.util.HashSet;
+import java.util.Set;
+
+
+/**
+ * @hide
+ */
+public class PrefixUtils {
+    private static final IpPrefix[] MIN_NON_FORWARDABLE_PREFIXES = {
+            pfx("127.0.0.0/8"),     // IPv4 loopback
+            pfx("169.254.0.0/16"),  // IPv4 link-local, RFC3927#section-8
+            pfx("::/3"),
+            pfx("fe80::/64"),       // IPv6 link-local
+            pfx("fc00::/7"),        // IPv6 ULA
+            pfx("ff02::/8"),        // IPv6 link-local multicast
+    };
+
+    public static final IpPrefix DEFAULT_WIFI_P2P_PREFIX = pfx("192.168.49.0/24");
+
+    /** Get non forwardable prefixes. */
+    public static Set<IpPrefix> getNonForwardablePrefixes() {
+        final HashSet<IpPrefix> prefixes = new HashSet<>();
+        addNonForwardablePrefixes(prefixes);
+        return prefixes;
+    }
+
+    /** Add non forwardable prefixes. */
+    public static void addNonForwardablePrefixes(Set<IpPrefix> prefixes) {
+        Collections.addAll(prefixes, MIN_NON_FORWARDABLE_PREFIXES);
+    }
+
+    /** Get local prefixes from |lp|. */
+    public static Set<IpPrefix> localPrefixesFrom(LinkProperties lp) {
+        final HashSet<IpPrefix> localPrefixes = new HashSet<>();
+        if (lp == null) return localPrefixes;
+
+        for (LinkAddress addr : lp.getAllLinkAddresses()) {
+            if (addr.getAddress().isLinkLocalAddress()) continue;
+            localPrefixes.add(asIpPrefix(addr));
+        }
+        // TODO: Add directly-connected routes as well (ones from which we did
+        // not also form a LinkAddress)?
+
+        return localPrefixes;
+    }
+
+    /** Convert LinkAddress |addr| to IpPrefix. */
+    public static IpPrefix asIpPrefix(LinkAddress addr) {
+        return new IpPrefix(addr.getAddress(), addr.getPrefixLength());
+    }
+
+    /** Convert InetAddress |ip| to IpPrefix. */
+    public static IpPrefix ipAddressAsPrefix(InetAddress ip) {
+        final int bitLength = (ip instanceof Inet4Address)
+                ? NetworkConstants.IPV4_ADDR_BITS
+                : NetworkConstants.IPV6_ADDR_BITS;
+        return new IpPrefix(ip, bitLength);
+    }
+
+    private static IpPrefix pfx(String prefixStr) {
+        return new IpPrefix(prefixStr);
+    }
+}
diff --git a/Tethering/src/android/net/util/TetheringMessageBase.java b/Tethering/src/android/net/util/TetheringMessageBase.java
new file mode 100644
index 0000000..29c0a81
--- /dev/null
+++ b/Tethering/src/android/net/util/TetheringMessageBase.java
@@ -0,0 +1,25 @@
+/*
+ * Copyright (C) 2020 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package android.net.util;
+
+/**
+ * This class defines Message.what base addresses for various state machine.
+ */
+public class TetheringMessageBase {
+    public static final int BASE_MAIN_SM   = 0;
+    public static final int BASE_IPSERVER = 100;
+
+}
diff --git a/Tethering/src/android/net/util/TetheringUtils.java b/Tethering/src/android/net/util/TetheringUtils.java
new file mode 100644
index 0000000..53b54f7
--- /dev/null
+++ b/Tethering/src/android/net/util/TetheringUtils.java
@@ -0,0 +1,165 @@
+/*
+ * Copyright (C) 2019 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package android.net.util;
+
+import android.net.TetherStatsParcel;
+import android.net.TetheringRequestParcel;
+import android.util.Log;
+
+import androidx.annotation.NonNull;
+
+import java.io.FileDescriptor;
+import java.net.Inet6Address;
+import java.net.SocketException;
+import java.net.UnknownHostException;
+import java.util.Arrays;
+import java.util.Objects;
+
+/**
+ * The classes and the methods for tethering utilization.
+ *
+ * {@hide}
+ */
+public class TetheringUtils {
+    public static final byte[] ALL_NODES = new byte[] {
+        (byte) 0xff, 2, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1
+    };
+
+    /**
+     * Configures a socket for receiving and sending ICMPv6 neighbor advertisments.
+     * @param fd the socket's {@link FileDescriptor}.
+     */
+    public static native void setupNaSocket(FileDescriptor fd)
+            throws SocketException;
+
+    /**
+     * Configures a socket for receiving and sending ICMPv6 neighbor solicitations.
+     * @param fd the socket's {@link FileDescriptor}.
+     */
+    public static native void setupNsSocket(FileDescriptor fd)
+            throws SocketException;
+
+    /**
+     *  The object which records offload Tx/Rx forwarded bytes/packets.
+     *  TODO: Replace the inner class ForwardedStats of class OffloadHardwareInterface with
+     *  this class as well.
+     */
+    public static class ForwardedStats {
+        public final long rxBytes;
+        public final long rxPackets;
+        public final long txBytes;
+        public final long txPackets;
+
+        public ForwardedStats() {
+            rxBytes = 0;
+            rxPackets = 0;
+            txBytes = 0;
+            txPackets = 0;
+        }
+
+        public ForwardedStats(long rxBytes, long txBytes) {
+            this.rxBytes = rxBytes;
+            this.rxPackets = 0;
+            this.txBytes = txBytes;
+            this.txPackets = 0;
+        }
+
+        public ForwardedStats(long rxBytes, long rxPackets, long txBytes, long txPackets) {
+            this.rxBytes = rxBytes;
+            this.rxPackets = rxPackets;
+            this.txBytes = txBytes;
+            this.txPackets = txPackets;
+        }
+
+        public ForwardedStats(@NonNull TetherStatsParcel tetherStats) {
+            rxBytes = tetherStats.rxBytes;
+            rxPackets = tetherStats.rxPackets;
+            txBytes = tetherStats.txBytes;
+            txPackets = tetherStats.txPackets;
+        }
+
+        public ForwardedStats(@NonNull ForwardedStats other) {
+            rxBytes = other.rxBytes;
+            rxPackets = other.rxPackets;
+            txBytes = other.txBytes;
+            txPackets = other.txPackets;
+        }
+
+        /** Add Tx/Rx bytes/packets and return the result as a new object. */
+        @NonNull
+        public ForwardedStats add(@NonNull ForwardedStats other) {
+            return new ForwardedStats(rxBytes + other.rxBytes, rxPackets + other.rxPackets,
+                    txBytes + other.txBytes, txPackets + other.txPackets);
+        }
+
+        /** Subtract Tx/Rx bytes/packets and return the result as a new object. */
+        @NonNull
+        public ForwardedStats subtract(@NonNull ForwardedStats other) {
+            // TODO: Perhaps throw an exception if any negative difference value just in case.
+            final long rxBytesDiff = Math.max(rxBytes - other.rxBytes, 0);
+            final long rxPacketsDiff = Math.max(rxPackets - other.rxPackets, 0);
+            final long txBytesDiff = Math.max(txBytes - other.txBytes, 0);
+            final long txPacketsDiff = Math.max(txPackets - other.txPackets, 0);
+            return new ForwardedStats(rxBytesDiff, rxPacketsDiff, txBytesDiff, txPacketsDiff);
+        }
+
+        /** Returns the string representation of this object. */
+        @NonNull
+        public String toString() {
+            return String.format("ForwardedStats(rxb: %d, rxp: %d, txb: %d, txp: %d)", rxBytes,
+                    rxPackets, txBytes, txPackets);
+        }
+    }
+
+    /**
+     * Configures a socket for receiving ICMPv6 router solicitations and sending advertisements.
+     * @param fd the socket's {@link FileDescriptor}.
+     * @param ifIndex the interface index.
+     */
+    public static native void setupRaSocket(FileDescriptor fd, int ifIndex)
+            throws SocketException;
+
+    /**
+     * Read s as an unsigned 16-bit integer.
+     */
+    public static int uint16(short s) {
+        return s & 0xffff;
+    }
+
+    /** Check whether two TetheringRequestParcels are the same. */
+    public static boolean isTetheringRequestEquals(final TetheringRequestParcel request,
+            final TetheringRequestParcel otherRequest) {
+        if (request == otherRequest) return true;
+
+        return request != null && otherRequest != null
+                && request.tetheringType == otherRequest.tetheringType
+                && Objects.equals(request.localIPv4Address, otherRequest.localIPv4Address)
+                && Objects.equals(request.staticClientAddress, otherRequest.staticClientAddress)
+                && request.exemptFromEntitlementCheck == otherRequest.exemptFromEntitlementCheck
+                && request.showProvisioningUi == otherRequest.showProvisioningUi;
+    }
+
+    /** Get inet6 address for all nodes given scope ID. */
+    public static Inet6Address getAllNodesForScopeId(int scopeId) {
+        try {
+            return Inet6Address.getByAddress("ff02::1", ALL_NODES, scopeId);
+        } catch (UnknownHostException uhe) {
+            Log.wtf("TetheringUtils", "Failed to construct Inet6Address from "
+                    + Arrays.toString(ALL_NODES) + " and scopedId " + scopeId);
+            return null;
+        }
+    }
+}
diff --git a/Tethering/src/android/net/util/VersionedBroadcastListener.java b/Tethering/src/android/net/util/VersionedBroadcastListener.java
new file mode 100644
index 0000000..e2804ab
--- /dev/null
+++ b/Tethering/src/android/net/util/VersionedBroadcastListener.java
@@ -0,0 +1,106 @@
+/*
+ * Copyright (C) 2017 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package android.net.util;
+
+import android.content.BroadcastReceiver;
+import android.content.Context;
+import android.content.Intent;
+import android.content.IntentFilter;
+import android.os.Handler;
+import android.util.Log;
+
+import java.util.concurrent.atomic.AtomicInteger;
+import java.util.function.Consumer;
+
+
+/**
+ * A utility class that runs the provided callback on the provided handler when
+ * intents matching the provided filter arrive. Intents received by a stale
+ * receiver are safely ignored.
+ *
+ * Calls to startListening() and stopListening() must happen on the same thread.
+ *
+ * @hide
+ */
+public class VersionedBroadcastListener {
+    private static final boolean DBG = false;
+
+    private final String mTag;
+    private final Context mContext;
+    private final Handler mHandler;
+    private final IntentFilter mFilter;
+    private final Consumer<Intent> mCallback;
+    private final AtomicInteger mGenerationNumber;
+    private BroadcastReceiver mReceiver;
+
+    public VersionedBroadcastListener(String tag, Context ctx, Handler handler,
+            IntentFilter filter, Consumer<Intent> callback) {
+        mTag = tag;
+        mContext = ctx;
+        mHandler = handler;
+        mFilter = filter;
+        mCallback = callback;
+        mGenerationNumber = new AtomicInteger(0);
+    }
+
+    /** Start listening to intent broadcast. */
+    public void startListening() {
+        if (DBG) Log.d(mTag, "startListening");
+        if (mReceiver != null) return;
+
+        mReceiver = new Receiver(mTag, mGenerationNumber, mCallback);
+        mContext.registerReceiver(mReceiver, mFilter, null, mHandler);
+    }
+
+    /** Stop listening to intent broadcast. */
+    public void stopListening() {
+        if (DBG) Log.d(mTag, "stopListening");
+        if (mReceiver == null) return;
+
+        mGenerationNumber.incrementAndGet();
+        mContext.unregisterReceiver(mReceiver);
+        mReceiver = null;
+    }
+
+    private static class Receiver extends BroadcastReceiver {
+        public final String tag;
+        public final AtomicInteger atomicGenerationNumber;
+        public final Consumer<Intent> callback;
+        // Used to verify this receiver is still current.
+        public final int generationNumber;
+
+        Receiver(String tag, AtomicInteger atomicGenerationNumber, Consumer<Intent> callback) {
+            this.tag = tag;
+            this.atomicGenerationNumber = atomicGenerationNumber;
+            this.callback = callback;
+            generationNumber = atomicGenerationNumber.incrementAndGet();
+        }
+
+        @Override
+        public void onReceive(Context context, Intent intent) {
+            final int currentGenerationNumber = atomicGenerationNumber.get();
+
+            if (DBG) {
+                Log.d(tag, "receiver generationNumber=" + generationNumber
+                        + ", current generationNumber=" + currentGenerationNumber);
+            }
+            if (generationNumber != currentGenerationNumber) return;
+
+            callback.accept(intent);
+        }
+    }
+}
diff --git a/Tethering/src/com/android/networkstack/tethering/BpfCoordinator.java b/Tethering/src/com/android/networkstack/tethering/BpfCoordinator.java
new file mode 100644
index 0000000..20f30ea
--- /dev/null
+++ b/Tethering/src/com/android/networkstack/tethering/BpfCoordinator.java
@@ -0,0 +1,778 @@
+/*
+ * Copyright (C) 2020 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.android.networkstack.tethering;
+
+import static android.net.NetworkStats.DEFAULT_NETWORK_NO;
+import static android.net.NetworkStats.METERED_NO;
+import static android.net.NetworkStats.ROAMING_NO;
+import static android.net.NetworkStats.SET_DEFAULT;
+import static android.net.NetworkStats.TAG_NONE;
+import static android.net.NetworkStats.UID_ALL;
+import static android.net.NetworkStats.UID_TETHERING;
+import static android.net.netstats.provider.NetworkStatsProvider.QUOTA_UNLIMITED;
+
+import static com.android.networkstack.tethering.TetheringConfiguration.DEFAULT_TETHER_OFFLOAD_POLL_INTERVAL_MS;
+
+import android.app.usage.NetworkStatsManager;
+import android.net.INetd;
+import android.net.MacAddress;
+import android.net.NetworkStats;
+import android.net.NetworkStats.Entry;
+import android.net.TetherOffloadRuleParcel;
+import android.net.TetherStatsParcel;
+import android.net.ip.IpServer;
+import android.net.netstats.provider.NetworkStatsProvider;
+import android.net.util.SharedLog;
+import android.net.util.TetheringUtils.ForwardedStats;
+import android.os.ConditionVariable;
+import android.os.Handler;
+import android.os.RemoteException;
+import android.os.ServiceSpecificException;
+import android.text.TextUtils;
+import android.util.Log;
+import android.util.SparseArray;
+
+import androidx.annotation.NonNull;
+import androidx.annotation.Nullable;
+
+import com.android.internal.annotations.VisibleForTesting;
+import com.android.internal.util.IndentingPrintWriter;
+
+import java.net.Inet6Address;
+import java.util.ArrayList;
+import java.util.HashMap;
+import java.util.LinkedHashMap;
+import java.util.Map;
+import java.util.Objects;
+
+/**
+ *  This coordinator is responsible for providing BPF offload relevant functionality.
+ *  - Get tethering stats.
+ *  - Set data limit.
+ *  - Set global alert.
+ *  - Add/remove forwarding rules.
+ *
+ * @hide
+ */
+public class BpfCoordinator {
+    private static final String TAG = BpfCoordinator.class.getSimpleName();
+    private static final int DUMP_TIMEOUT_MS = 10_000;
+
+    @VisibleForTesting
+    enum StatsType {
+        STATS_PER_IFACE,
+        STATS_PER_UID,
+    }
+
+    @NonNull
+    private final Handler mHandler;
+    @NonNull
+    private final INetd mNetd;
+    @NonNull
+    private final SharedLog mLog;
+    @NonNull
+    private final Dependencies mDeps;
+    @Nullable
+    private final BpfTetherStatsProvider mStatsProvider;
+
+    // True if BPF offload is supported, false otherwise. The BPF offload could be disabled by
+    // a runtime resource overlay package or device configuration. This flag is only initialized
+    // in the constructor because it is hard to unwind all existing change once device
+    // configuration is changed. Especially the forwarding rules. Keep the same setting
+    // to make it simpler. See also TetheringConfiguration.
+    private final boolean mIsBpfEnabled;
+
+    // Tracks whether BPF tethering is started or not. This is set by tethering before it
+    // starts the first IpServer and is cleared by tethering shortly before the last IpServer
+    // is stopped. Note that rule updates (especially deletions, but sometimes additions as
+    // well) may arrive when this is false. If they do, they must be communicated to netd.
+    // Changes in data limits may also arrive when this is false, and if they do, they must
+    // also be communicated to netd.
+    private boolean mPollingStarted = false;
+
+    // Tracking remaining alert quota. Unlike limit quota is subject to interface, the alert
+    // quota is interface independent and global for tether offload.
+    private long mRemainingAlertQuota = QUOTA_UNLIMITED;
+
+    // Maps upstream interface index to offloaded traffic statistics.
+    // Always contains the latest total bytes/packets, since each upstream was started, received
+    // from the BPF maps for each interface.
+    private final SparseArray<ForwardedStats> mStats = new SparseArray<>();
+
+    // Maps upstream interface names to interface quotas.
+    // Always contains the latest value received from the framework for each interface, regardless
+    // of whether offload is currently running (or is even supported) on that interface. Only
+    // includes interfaces that have a quota set. Note that this map is used for storing the quota
+    // which is set from the service. Because the service uses the interface name to present the
+    // interface, this map uses the interface name to be the mapping index.
+    private final HashMap<String, Long> mInterfaceQuotas = new HashMap<>();
+
+    // Maps upstream interface index to interface names.
+    // Store all interface name since boot. Used for lookup what interface name it is from the
+    // tether stats got from netd because netd reports interface index to present an interface.
+    // TODO: Remove the unused interface name.
+    private final SparseArray<String> mInterfaceNames = new SparseArray<>();
+
+    // Map of downstream rule maps. Each of these maps represents the IPv6 forwarding rules for a
+    // given downstream. Each map:
+    // - Is owned by the IpServer that is responsible for that downstream.
+    // - Must only be modified by that IpServer.
+    // - Is created when the IpServer adds its first rule, and deleted when the IpServer deletes
+    //   its last rule (or clears its rules).
+    // TODO: Perhaps seal the map and rule operations which communicates with netd into a class.
+    // TODO: Does this need to be a LinkedHashMap or can it just be a HashMap? Also, could it be
+    // a ConcurrentHashMap, in order to avoid the copies in tetherOffloadRuleClear
+    // and tetherOffloadRuleUpdate?
+    // TODO: Perhaps use one-dimensional map and access specific downstream rules via downstream
+    // index. For doing that, IpServer must guarantee that it always has a valid IPv6 downstream
+    // interface index while calling function to clear all rules. IpServer may be calling clear
+    // rules function without a valid IPv6 downstream interface index even if it may have one
+    // before. IpServer would need to call getInterfaceParams() in the constructor instead of when
+    // startIpv6() is called, and make mInterfaceParams final.
+    private final HashMap<IpServer, LinkedHashMap<Inet6Address, Ipv6ForwardingRule>>
+            mIpv6ForwardingRules = new LinkedHashMap<>();
+
+    // Runnable that used by scheduling next polling of stats.
+    private final Runnable mScheduledPollingTask = () -> {
+        updateForwardedStatsFromNetd();
+        maybeSchedulePollingStats();
+    };
+
+    @VisibleForTesting
+    public abstract static class Dependencies {
+        /** Get handler. */
+        @NonNull public abstract Handler getHandler();
+
+        /** Get netd. */
+        @NonNull public abstract INetd getNetd();
+
+        /** Get network stats manager. */
+        @NonNull public abstract NetworkStatsManager getNetworkStatsManager();
+
+        /** Get shared log. */
+        @NonNull public abstract SharedLog getSharedLog();
+
+        /** Get tethering configuration. */
+        @Nullable public abstract TetheringConfiguration getTetherConfig();
+    }
+
+    @VisibleForTesting
+    public BpfCoordinator(@NonNull Dependencies deps) {
+        mDeps = deps;
+        mHandler = mDeps.getHandler();
+        mNetd = mDeps.getNetd();
+        mLog = mDeps.getSharedLog().forSubComponent(TAG);
+        mIsBpfEnabled = isBpfEnabled();
+        BpfTetherStatsProvider provider = new BpfTetherStatsProvider();
+        try {
+            mDeps.getNetworkStatsManager().registerNetworkStatsProvider(
+                    getClass().getSimpleName(), provider);
+        } catch (RuntimeException e) {
+            // TODO: Perhaps not allow to use BPF offload because the reregistration failure
+            // implied that no data limit could be applies on a metered upstream if any.
+            Log.wtf(TAG, "Cannot register offload stats provider: " + e);
+            provider = null;
+        }
+        mStatsProvider = provider;
+    }
+
+    /**
+     * Start BPF tethering offload stats polling when the first upstream is started.
+     * Note that this can be only called on handler thread.
+     * TODO: Perhaps check BPF support before starting.
+     * TODO: Start the stats polling only if there is any client on the downstream.
+     */
+    public void startPolling() {
+        if (mPollingStarted) return;
+
+        if (!mIsBpfEnabled) {
+            mLog.i("Offload disabled");
+            return;
+        }
+
+        mPollingStarted = true;
+        maybeSchedulePollingStats();
+
+        mLog.i("Polling started");
+    }
+
+    /**
+     * Stop BPF tethering offload stats polling.
+     * The data limit cleanup and the tether stats maps cleanup are not implemented here.
+     * These cleanups rely on all IpServers calling #tetherOffloadRuleRemove. After the
+     * last rule is removed from the upstream, #tetherOffloadRuleRemove does the cleanup
+     * functionality.
+     * Note that this can be only called on handler thread.
+     */
+    public void stopPolling() {
+        if (!mPollingStarted) return;
+
+        // Stop scheduled polling tasks and poll the latest stats from BPF maps.
+        if (mHandler.hasCallbacks(mScheduledPollingTask)) {
+            mHandler.removeCallbacks(mScheduledPollingTask);
+        }
+        updateForwardedStatsFromNetd();
+        mPollingStarted = false;
+
+        mLog.i("Polling stopped");
+    }
+
+    /**
+     * Add forwarding rule. After adding the first rule on a given upstream, must add the data
+     * limit on the given upstream.
+     * Note that this can be only called on handler thread.
+     */
+    public void tetherOffloadRuleAdd(
+            @NonNull final IpServer ipServer, @NonNull final Ipv6ForwardingRule rule) {
+        if (!mIsBpfEnabled) return;
+
+        try {
+            // TODO: Perhaps avoid to add a duplicate rule.
+            mNetd.tetherOffloadRuleAdd(rule.toTetherOffloadRuleParcel());
+        } catch (RemoteException | ServiceSpecificException e) {
+            mLog.e("Could not add IPv6 forwarding rule: ", e);
+            return;
+        }
+
+        if (!mIpv6ForwardingRules.containsKey(ipServer)) {
+            mIpv6ForwardingRules.put(ipServer, new LinkedHashMap<Inet6Address,
+                    Ipv6ForwardingRule>());
+        }
+        LinkedHashMap<Inet6Address, Ipv6ForwardingRule> rules = mIpv6ForwardingRules.get(ipServer);
+
+        // Setup the data limit on the given upstream if the first rule is added.
+        final int upstreamIfindex = rule.upstreamIfindex;
+        if (!isAnyRuleOnUpstream(upstreamIfindex)) {
+            // If failed to set a data limit, probably should not use this upstream, because
+            // the upstream may not want to blow through the data limit that was told to apply.
+            // TODO: Perhaps stop the coordinator.
+            boolean success = updateDataLimit(upstreamIfindex);
+            if (!success) {
+                final String iface = mInterfaceNames.get(upstreamIfindex);
+                mLog.e("Setting data limit for " + iface + " failed.");
+            }
+        }
+
+        // Must update the adding rule after calling #isAnyRuleOnUpstream because it needs to
+        // check if it is about adding a first rule for a given upstream.
+        rules.put(rule.address, rule);
+    }
+
+    /**
+     * Remove forwarding rule. After removing the last rule on a given upstream, must clear
+     * data limit, update the last tether stats and remove the tether stats in the BPF maps.
+     * Note that this can be only called on handler thread.
+     */
+    public void tetherOffloadRuleRemove(
+            @NonNull final IpServer ipServer, @NonNull final Ipv6ForwardingRule rule) {
+        if (!mIsBpfEnabled) return;
+
+        try {
+            // TODO: Perhaps avoid to remove a non-existent rule.
+            mNetd.tetherOffloadRuleRemove(rule.toTetherOffloadRuleParcel());
+        } catch (RemoteException | ServiceSpecificException e) {
+            mLog.e("Could not remove IPv6 forwarding rule: ", e);
+            return;
+        }
+
+        LinkedHashMap<Inet6Address, Ipv6ForwardingRule> rules = mIpv6ForwardingRules.get(ipServer);
+        if (rules == null) return;
+
+        // Must remove rules before calling #isAnyRuleOnUpstream because it needs to check if
+        // the last rule is removed for a given upstream. If no rule is removed, return early.
+        // Avoid unnecessary work on a non-existent rule which may have never been added or
+        // removed already.
+        if (rules.remove(rule.address) == null) return;
+
+        // Remove the downstream entry if it has no more rule.
+        if (rules.isEmpty()) {
+            mIpv6ForwardingRules.remove(ipServer);
+        }
+
+        // Do cleanup functionality if there is no more rule on the given upstream.
+        final int upstreamIfindex = rule.upstreamIfindex;
+        if (!isAnyRuleOnUpstream(upstreamIfindex)) {
+            try {
+                final TetherStatsParcel stats =
+                        mNetd.tetherOffloadGetAndClearStats(upstreamIfindex);
+                // Update the last stats delta and delete the local cache for a given upstream.
+                updateQuotaAndStatsFromSnapshot(new TetherStatsParcel[] {stats});
+                mStats.remove(upstreamIfindex);
+            } catch (RemoteException | ServiceSpecificException e) {
+                Log.wtf(TAG, "Exception when cleanup tether stats for upstream index "
+                        + upstreamIfindex + ": ", e);
+            }
+        }
+    }
+
+    /**
+     * Clear all forwarding rules for a given downstream.
+     * Note that this can be only called on handler thread.
+     */
+    public void tetherOffloadRuleClear(@NonNull final IpServer ipServer) {
+        if (!mIsBpfEnabled) return;
+
+        final LinkedHashMap<Inet6Address, Ipv6ForwardingRule> rules = mIpv6ForwardingRules.get(
+                ipServer);
+        if (rules == null) return;
+
+        // Need to build a rule list because the rule map may be changed in the iteration.
+        for (final Ipv6ForwardingRule rule : new ArrayList<Ipv6ForwardingRule>(rules.values())) {
+            tetherOffloadRuleRemove(ipServer, rule);
+        }
+    }
+
+    /**
+     * Update existing forwarding rules to new upstream for a given downstream.
+     * Note that this can be only called on handler thread.
+     */
+    public void tetherOffloadRuleUpdate(@NonNull final IpServer ipServer, int newUpstreamIfindex) {
+        if (!mIsBpfEnabled) return;
+
+        final LinkedHashMap<Inet6Address, Ipv6ForwardingRule> rules = mIpv6ForwardingRules.get(
+                ipServer);
+        if (rules == null) return;
+
+        // Need to build a rule list because the rule map may be changed in the iteration.
+        for (final Ipv6ForwardingRule rule : new ArrayList<Ipv6ForwardingRule>(rules.values())) {
+            // Remove the old rule before adding the new one because the map uses the same key for
+            // both rules. Reversing the processing order causes that the new rule is removed as
+            // unexpected.
+            // TODO: Add new rule first to reduce the latency which has no rule.
+            tetherOffloadRuleRemove(ipServer, rule);
+            tetherOffloadRuleAdd(ipServer, rule.onNewUpstream(newUpstreamIfindex));
+        }
+    }
+
+    /**
+     * Add upstream name to lookup table. The lookup table is used for tether stats interface name
+     * lookup because the netd only reports interface index in BPF tether stats but the service
+     * expects the interface name in NetworkStats object.
+     * Note that this can be only called on handler thread.
+     */
+    public void addUpstreamNameToLookupTable(int upstreamIfindex, @NonNull String upstreamIface) {
+        if (!mIsBpfEnabled) return;
+
+        if (upstreamIfindex == 0 || TextUtils.isEmpty(upstreamIface)) return;
+
+        // The same interface index to name mapping may be added by different IpServer objects or
+        // re-added by reconnection on the same upstream interface. Ignore the duplicate one.
+        final String iface = mInterfaceNames.get(upstreamIfindex);
+        if (iface == null) {
+            mInterfaceNames.put(upstreamIfindex, upstreamIface);
+        } else if (!TextUtils.equals(iface, upstreamIface)) {
+            Log.wtf(TAG, "The upstream interface name " + upstreamIface
+                    + " is different from the existing interface name "
+                    + iface + " for index " + upstreamIfindex);
+        }
+    }
+
+    /**
+     * Dump information.
+     * Block the function until all the data are dumped on the handler thread or timed-out. The
+     * reason is that dumpsys invokes this function on the thread of caller and the data may only
+     * be allowed to be accessed on the handler thread.
+     */
+    public void dump(@NonNull IndentingPrintWriter pw) {
+        final ConditionVariable dumpDone = new ConditionVariable();
+        mHandler.post(() -> {
+            pw.println("mIsBpfEnabled: " + mIsBpfEnabled);
+            pw.println("Polling " + (mPollingStarted ? "started" : "not started"));
+            pw.println("Stats provider " + (mStatsProvider != null
+                    ? "registered" : "not registered"));
+            pw.println("Upstream quota: " + mInterfaceQuotas.toString());
+            pw.println("Polling interval: " + getPollingInterval() + " ms");
+
+            pw.println("Forwarding stats:");
+            pw.increaseIndent();
+            if (mStats.size() == 0) {
+                pw.println("<empty>");
+            } else {
+                dumpStats(pw);
+            }
+            pw.decreaseIndent();
+
+            pw.println("Forwarding rules:");
+            pw.increaseIndent();
+            if (mIpv6ForwardingRules.size() == 0) {
+                pw.println("<empty>");
+            } else {
+                dumpIpv6ForwardingRules(pw);
+            }
+            pw.decreaseIndent();
+
+            dumpDone.open();
+        });
+        if (!dumpDone.block(DUMP_TIMEOUT_MS)) {
+            pw.println("... dump timed-out after " + DUMP_TIMEOUT_MS + "ms");
+        }
+    }
+
+    private void dumpStats(@NonNull IndentingPrintWriter pw) {
+        for (int i = 0; i < mStats.size(); i++) {
+            final int upstreamIfindex = mStats.keyAt(i);
+            final ForwardedStats stats = mStats.get(upstreamIfindex);
+            pw.println(String.format("%d(%s) - %s", upstreamIfindex, mInterfaceNames.get(
+                    upstreamIfindex), stats.toString()));
+        }
+    }
+
+    private void dumpIpv6ForwardingRules(@NonNull IndentingPrintWriter pw) {
+        for (Map.Entry<IpServer, LinkedHashMap<Inet6Address, Ipv6ForwardingRule>> entry :
+                mIpv6ForwardingRules.entrySet()) {
+            IpServer ipServer = entry.getKey();
+            // The rule downstream interface index is paired with the interface name from
+            // IpServer#interfaceName. See #startIPv6, #updateIpv6ForwardingRules in IpServer.
+            final String downstreamIface = ipServer.interfaceName();
+            pw.println("[" + downstreamIface + "]: iif(iface) oif(iface) v6addr srcmac dstmac");
+
+            pw.increaseIndent();
+            LinkedHashMap<Inet6Address, Ipv6ForwardingRule> rules = entry.getValue();
+            for (Ipv6ForwardingRule rule : rules.values()) {
+                final int upstreamIfindex = rule.upstreamIfindex;
+                pw.println(String.format("%d(%s) %d(%s) %s %s %s", upstreamIfindex,
+                        mInterfaceNames.get(upstreamIfindex), rule.downstreamIfindex,
+                        downstreamIface, rule.address, rule.srcMac, rule.dstMac));
+            }
+            pw.decreaseIndent();
+        }
+    }
+
+    /** IPv6 forwarding rule class. */
+    public static class Ipv6ForwardingRule {
+        public final int upstreamIfindex;
+        public final int downstreamIfindex;
+
+        @NonNull
+        public final Inet6Address address;
+        @NonNull
+        public final MacAddress srcMac;
+        @NonNull
+        public final MacAddress dstMac;
+
+        public Ipv6ForwardingRule(int upstreamIfindex, int downstreamIfIndex,
+                @NonNull Inet6Address address, @NonNull MacAddress srcMac,
+                @NonNull MacAddress dstMac) {
+            this.upstreamIfindex = upstreamIfindex;
+            this.downstreamIfindex = downstreamIfIndex;
+            this.address = address;
+            this.srcMac = srcMac;
+            this.dstMac = dstMac;
+        }
+
+        /** Return a new rule object which updates with new upstream index. */
+        @NonNull
+        public Ipv6ForwardingRule onNewUpstream(int newUpstreamIfindex) {
+            return new Ipv6ForwardingRule(newUpstreamIfindex, downstreamIfindex, address, srcMac,
+                    dstMac);
+        }
+
+        /**
+         * Don't manipulate TetherOffloadRuleParcel directly because implementing onNewUpstream()
+         * would be error-prone due to generated stable AIDL classes not having a copy constructor.
+         */
+        @NonNull
+        public TetherOffloadRuleParcel toTetherOffloadRuleParcel() {
+            final TetherOffloadRuleParcel parcel = new TetherOffloadRuleParcel();
+            parcel.inputInterfaceIndex = upstreamIfindex;
+            parcel.outputInterfaceIndex = downstreamIfindex;
+            parcel.destination = address.getAddress();
+            parcel.prefixLength = 128;
+            parcel.srcL2Address = srcMac.toByteArray();
+            parcel.dstL2Address = dstMac.toByteArray();
+            return parcel;
+        }
+
+        @Override
+        public boolean equals(Object o) {
+            if (!(o instanceof Ipv6ForwardingRule)) return false;
+            Ipv6ForwardingRule that = (Ipv6ForwardingRule) o;
+            return this.upstreamIfindex == that.upstreamIfindex
+                    && this.downstreamIfindex == that.downstreamIfindex
+                    && Objects.equals(this.address, that.address)
+                    && Objects.equals(this.srcMac, that.srcMac)
+                    && Objects.equals(this.dstMac, that.dstMac);
+        }
+
+        @Override
+        public int hashCode() {
+            // TODO: if this is ever used in production code, don't pass ifindices
+            // to Objects.hash() to avoid autoboxing overhead.
+            return Objects.hash(upstreamIfindex, downstreamIfindex, address, srcMac, dstMac);
+        }
+    }
+
+    /**
+     * A BPF tethering stats provider to provide network statistics to the system.
+     * Note that this class' data may only be accessed on the handler thread.
+     */
+    @VisibleForTesting
+    class BpfTetherStatsProvider extends NetworkStatsProvider {
+        // The offloaded traffic statistics per interface that has not been reported since the
+        // last call to pushTetherStats. Only the interfaces that were ever tethering upstreams
+        // and has pending tether stats delta are included in this NetworkStats object.
+        private NetworkStats mIfaceStats = new NetworkStats(0L, 0);
+
+        // The same stats as above, but counts network stats per uid.
+        private NetworkStats mUidStats = new NetworkStats(0L, 0);
+
+        @Override
+        public void onRequestStatsUpdate(int token) {
+            mHandler.post(() -> pushTetherStats());
+        }
+
+        @Override
+        public void onSetAlert(long quotaBytes) {
+            mHandler.post(() -> updateAlertQuota(quotaBytes));
+        }
+
+        @Override
+        public void onSetLimit(@NonNull String iface, long quotaBytes) {
+            if (quotaBytes < QUOTA_UNLIMITED) {
+                throw new IllegalArgumentException("invalid quota value " + quotaBytes);
+            }
+
+            mHandler.post(() -> {
+                final Long curIfaceQuota = mInterfaceQuotas.get(iface);
+
+                if (null == curIfaceQuota && QUOTA_UNLIMITED == quotaBytes) return;
+
+                if (quotaBytes == QUOTA_UNLIMITED) {
+                    mInterfaceQuotas.remove(iface);
+                } else {
+                    mInterfaceQuotas.put(iface, quotaBytes);
+                }
+                maybeUpdateDataLimit(iface);
+            });
+        }
+
+        @VisibleForTesting
+        void pushTetherStats() {
+            try {
+                // The token is not used for now. See b/153606961.
+                notifyStatsUpdated(0 /* token */, mIfaceStats, mUidStats);
+
+                // Clear the accumulated tether stats delta after reported. Note that create a new
+                // empty object because NetworkStats#clear is @hide.
+                mIfaceStats = new NetworkStats(0L, 0);
+                mUidStats = new NetworkStats(0L, 0);
+            } catch (RuntimeException e) {
+                mLog.e("Cannot report network stats: ", e);
+            }
+        }
+
+        private void accumulateDiff(@NonNull NetworkStats ifaceDiff,
+                @NonNull NetworkStats uidDiff) {
+            mIfaceStats = mIfaceStats.add(ifaceDiff);
+            mUidStats = mUidStats.add(uidDiff);
+        }
+    }
+
+    private boolean isBpfEnabled() {
+        final TetheringConfiguration config = mDeps.getTetherConfig();
+        return (config != null) ? config.isBpfOffloadEnabled() : true /* default value */;
+    }
+
+    private int getInterfaceIndexFromRules(@NonNull String ifName) {
+        for (LinkedHashMap<Inet6Address, Ipv6ForwardingRule> rules : mIpv6ForwardingRules
+                .values()) {
+            for (Ipv6ForwardingRule rule : rules.values()) {
+                final int upstreamIfindex = rule.upstreamIfindex;
+                if (TextUtils.equals(ifName, mInterfaceNames.get(upstreamIfindex))) {
+                    return upstreamIfindex;
+                }
+            }
+        }
+        return 0;
+    }
+
+    private long getQuotaBytes(@NonNull String iface) {
+        final Long limit = mInterfaceQuotas.get(iface);
+        final long quotaBytes = (limit != null) ? limit : QUOTA_UNLIMITED;
+
+        return quotaBytes;
+    }
+
+    private boolean sendDataLimitToNetd(int ifIndex, long quotaBytes) {
+        if (ifIndex == 0) {
+            Log.wtf(TAG, "Invalid interface index.");
+            return false;
+        }
+
+        try {
+            mNetd.tetherOffloadSetInterfaceQuota(ifIndex, quotaBytes);
+        } catch (RemoteException | ServiceSpecificException e) {
+            mLog.e("Exception when updating quota " + quotaBytes + ": ", e);
+            return false;
+        }
+
+        return true;
+    }
+
+    // Handle the data limit update from the service which is the stats provider registered for.
+    private void maybeUpdateDataLimit(@NonNull String iface) {
+        // Set data limit only on a given upstream which has at least one rule. If we can't get
+        // an interface index for a given interface name, it means either there is no rule for
+        // a given upstream or the interface name is not an upstream which is monitored by the
+        // coordinator.
+        final int ifIndex = getInterfaceIndexFromRules(iface);
+        if (ifIndex == 0) return;
+
+        final long quotaBytes = getQuotaBytes(iface);
+        sendDataLimitToNetd(ifIndex, quotaBytes);
+    }
+
+    // Handle the data limit update while adding forwarding rules.
+    private boolean updateDataLimit(int ifIndex) {
+        final String iface = mInterfaceNames.get(ifIndex);
+        if (iface == null) {
+            mLog.e("Fail to get the interface name for index " + ifIndex);
+            return false;
+        }
+        final long quotaBytes = getQuotaBytes(iface);
+        return sendDataLimitToNetd(ifIndex, quotaBytes);
+    }
+
+    private boolean isAnyRuleOnUpstream(int upstreamIfindex) {
+        for (LinkedHashMap<Inet6Address, Ipv6ForwardingRule> rules : mIpv6ForwardingRules
+                .values()) {
+            for (Ipv6ForwardingRule rule : rules.values()) {
+                if (upstreamIfindex == rule.upstreamIfindex) return true;
+            }
+        }
+        return false;
+    }
+
+    @NonNull
+    private NetworkStats buildNetworkStats(@NonNull StatsType type, int ifIndex,
+            @NonNull final ForwardedStats diff) {
+        NetworkStats stats = new NetworkStats(0L, 0);
+        final String iface = mInterfaceNames.get(ifIndex);
+        if (iface == null) {
+            // TODO: Use Log.wtf once the coordinator owns full control of tether stats from netd.
+            // For now, netd may add the empty stats for the upstream which is not monitored by
+            // the coordinator. Silently ignore it.
+            return stats;
+        }
+        final int uid = (type == StatsType.STATS_PER_UID) ? UID_TETHERING : UID_ALL;
+        // Note that the argument 'metered', 'roaming' and 'defaultNetwork' are not recorded for
+        // network stats snapshot. See NetworkStatsRecorder#recordSnapshotLocked.
+        return stats.addEntry(new Entry(iface, uid, SET_DEFAULT, TAG_NONE, METERED_NO,
+                ROAMING_NO, DEFAULT_NETWORK_NO, diff.rxBytes, diff.rxPackets,
+                diff.txBytes, diff.txPackets, 0L /* operations */));
+    }
+
+    private void updateAlertQuota(long newQuota) {
+        if (newQuota < QUOTA_UNLIMITED) {
+            throw new IllegalArgumentException("invalid quota value " + newQuota);
+        }
+        if (mRemainingAlertQuota == newQuota) return;
+
+        mRemainingAlertQuota = newQuota;
+        if (mRemainingAlertQuota == 0) {
+            mLog.i("onAlertReached");
+            if (mStatsProvider != null) mStatsProvider.notifyAlertReached();
+        }
+    }
+
+    private void updateQuotaAndStatsFromSnapshot(
+            @NonNull final TetherStatsParcel[] tetherStatsList) {
+        long usedAlertQuota = 0;
+        for (TetherStatsParcel tetherStats : tetherStatsList) {
+            final Integer ifIndex = tetherStats.ifIndex;
+            final ForwardedStats curr = new ForwardedStats(tetherStats);
+            final ForwardedStats base = mStats.get(ifIndex);
+            final ForwardedStats diff = (base != null) ? curr.subtract(base) : curr;
+            usedAlertQuota += diff.rxBytes + diff.txBytes;
+
+            // Update the local cache for counting tether stats delta.
+            mStats.put(ifIndex, curr);
+
+            // Update the accumulated tether stats delta to the stats provider for the service
+            // querying.
+            if (mStatsProvider != null) {
+                try {
+                    mStatsProvider.accumulateDiff(
+                            buildNetworkStats(StatsType.STATS_PER_IFACE, ifIndex, diff),
+                            buildNetworkStats(StatsType.STATS_PER_UID, ifIndex, diff));
+                } catch (ArrayIndexOutOfBoundsException e) {
+                    Log.wtf(TAG, "Fail to update the accumulated stats delta for interface index "
+                            + ifIndex + " : ", e);
+                }
+            }
+        }
+
+        if (mRemainingAlertQuota > 0 && usedAlertQuota > 0) {
+            // Trim to zero if overshoot.
+            final long newQuota = Math.max(mRemainingAlertQuota - usedAlertQuota, 0);
+            updateAlertQuota(newQuota);
+        }
+
+        // TODO: Count the used limit quota for notifying data limit reached.
+    }
+
+    private void updateForwardedStatsFromNetd() {
+        final TetherStatsParcel[] tetherStatsList;
+        try {
+            // The reported tether stats are total data usage for all currently-active upstream
+            // interfaces since tethering start.
+            tetherStatsList = mNetd.tetherOffloadGetStats();
+        } catch (RemoteException | ServiceSpecificException e) {
+            mLog.e("Problem fetching tethering stats: ", e);
+            return;
+        }
+        updateQuotaAndStatsFromSnapshot(tetherStatsList);
+    }
+
+    @VisibleForTesting
+    int getPollingInterval() {
+        // The valid range of interval is DEFAULT_TETHER_OFFLOAD_POLL_INTERVAL_MS..max_long.
+        // Ignore the config value is less than the minimum polling interval. Note that the
+        // minimum interval definition is invoked as OffloadController#isPollingStatsNeeded does.
+        // TODO: Perhaps define a minimum polling interval constant.
+        final TetheringConfiguration config = mDeps.getTetherConfig();
+        final int configInterval = (config != null) ? config.getOffloadPollInterval() : 0;
+        return Math.max(DEFAULT_TETHER_OFFLOAD_POLL_INTERVAL_MS, configInterval);
+    }
+
+    private void maybeSchedulePollingStats() {
+        if (!mPollingStarted) return;
+
+        if (mHandler.hasCallbacks(mScheduledPollingTask)) {
+            mHandler.removeCallbacks(mScheduledPollingTask);
+        }
+
+        mHandler.postDelayed(mScheduledPollingTask, getPollingInterval());
+    }
+
+    // Return forwarding rule map. This is used for testing only.
+    // Note that this can be only called on handler thread.
+    @NonNull
+    @VisibleForTesting
+    final HashMap<IpServer, LinkedHashMap<Inet6Address, Ipv6ForwardingRule>>
+            getForwardingRulesForTesting() {
+        return mIpv6ForwardingRules;
+    }
+
+    // Return upstream interface name map. This is used for testing only.
+    // Note that this can be only called on handler thread.
+    @NonNull
+    @VisibleForTesting
+    final SparseArray<String> getInterfaceNamesForTesting() {
+        return mInterfaceNames;
+    }
+}
diff --git a/Tethering/src/com/android/networkstack/tethering/ConnectedClientsTracker.java b/Tethering/src/com/android/networkstack/tethering/ConnectedClientsTracker.java
new file mode 100644
index 0000000..8a96988
--- /dev/null
+++ b/Tethering/src/com/android/networkstack/tethering/ConnectedClientsTracker.java
@@ -0,0 +1,183 @@
+/*
+ * Copyright (C) 2020 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.android.networkstack.tethering;
+
+import static android.net.TetheringManager.TETHERING_WIFI;
+
+import android.net.MacAddress;
+import android.net.TetheredClient;
+import android.net.TetheredClient.AddressInfo;
+import android.net.ip.IpServer;
+import android.net.wifi.WifiClient;
+import android.os.SystemClock;
+
+import androidx.annotation.NonNull;
+import androidx.annotation.Nullable;
+import androidx.annotation.VisibleForTesting;
+
+import java.util.ArrayList;
+import java.util.Collections;
+import java.util.HashMap;
+import java.util.HashSet;
+import java.util.List;
+import java.util.Map;
+import java.util.Set;
+
+/**
+ * Tracker for clients connected to downstreams.
+ *
+ * <p>This class is not thread safe, it is intended to be used only from the tethering handler
+ * thread.
+ */
+public class ConnectedClientsTracker {
+    private final Clock mClock;
+
+    @NonNull
+    private List<WifiClient> mLastWifiClients = Collections.emptyList();
+    @NonNull
+    private List<TetheredClient> mLastTetheredClients = Collections.emptyList();
+
+    @VisibleForTesting
+    static class Clock {
+        public long elapsedRealtime() {
+            return SystemClock.elapsedRealtime();
+        }
+    }
+
+    public ConnectedClientsTracker() {
+        this(new Clock());
+    }
+
+    @VisibleForTesting
+    ConnectedClientsTracker(Clock clock) {
+        mClock = clock;
+    }
+
+    /**
+     * Update the tracker with new connected clients.
+     *
+     * <p>The new list can be obtained through {@link #getLastTetheredClients()}.
+     * @param ipServers The IpServers used to assign addresses to clients.
+     * @param wifiClients The list of L2-connected WiFi clients. Null for no change since last
+     *                    update.
+     * @return True if the list of clients changed since the last calculation.
+     */
+    public boolean updateConnectedClients(
+            Iterable<IpServer> ipServers, @Nullable List<WifiClient> wifiClients) {
+        final long now = mClock.elapsedRealtime();
+
+        if (wifiClients != null) {
+            mLastWifiClients = wifiClients;
+        }
+        final Set<MacAddress> wifiClientMacs = getClientMacs(mLastWifiClients);
+
+        // Build the list of non-expired leases from all IpServers, grouped by mac address
+        final Map<MacAddress, TetheredClient> clientsMap = new HashMap<>();
+        for (IpServer server : ipServers) {
+            for (TetheredClient client : server.getAllLeases()) {
+                if (client.getTetheringType() == TETHERING_WIFI
+                        && !wifiClientMacs.contains(client.getMacAddress())) {
+                    // Skip leases of WiFi clients that are not (or no longer) L2-connected
+                    continue;
+                }
+                final TetheredClient prunedClient = pruneExpired(client, now);
+                if (prunedClient == null) continue; // All addresses expired
+
+                addLease(clientsMap, prunedClient);
+            }
+        }
+
+        // TODO: add IPv6 addresses from netlink
+
+        // Add connected WiFi clients that do not have any known address
+        for (MacAddress client : wifiClientMacs) {
+            if (clientsMap.containsKey(client)) continue;
+            clientsMap.put(client, new TetheredClient(
+                    client, Collections.emptyList() /* addresses */, TETHERING_WIFI));
+        }
+
+        final HashSet<TetheredClient> clients = new HashSet<>(clientsMap.values());
+        final boolean clientsChanged = clients.size() != mLastTetheredClients.size()
+                || !clients.containsAll(mLastTetheredClients);
+        mLastTetheredClients = Collections.unmodifiableList(new ArrayList<>(clients));
+        return clientsChanged;
+    }
+
+    private static void addLease(Map<MacAddress, TetheredClient> clientsMap, TetheredClient lease) {
+        final TetheredClient aggregateClient = clientsMap.getOrDefault(
+                lease.getMacAddress(), lease);
+        if (aggregateClient == lease) {
+            // This is the first lease with this mac address
+            clientsMap.put(lease.getMacAddress(), lease);
+            return;
+        }
+
+        // Only add the address info; this assumes that the tethering type is the same when the mac
+        // address is the same. If a client is connected through different tethering types with the
+        // same mac address, connected clients callbacks will report all of its addresses under only
+        // one of these tethering types. This keeps the API simple considering that such a scenario
+        // would really be a rare edge case.
+        clientsMap.put(lease.getMacAddress(), aggregateClient.addAddresses(lease));
+    }
+
+    /**
+     * Get the last list of tethered clients, as calculated in {@link #updateConnectedClients}.
+     *
+     * <p>The returned list is immutable.
+     */
+    @NonNull
+    public List<TetheredClient> getLastTetheredClients() {
+        return mLastTetheredClients;
+    }
+
+    private static boolean hasExpiredAddress(List<AddressInfo> addresses, long now) {
+        for (AddressInfo info : addresses) {
+            if (info.getExpirationTime() <= now) {
+                return true;
+            }
+        }
+        return false;
+    }
+
+    @Nullable
+    private static TetheredClient pruneExpired(TetheredClient client, long now) {
+        final List<AddressInfo> addresses = client.getAddresses();
+        if (addresses.size() == 0) return null;
+        if (!hasExpiredAddress(addresses, now)) return client;
+
+        final ArrayList<AddressInfo> newAddrs = new ArrayList<>(addresses.size() - 1);
+        for (AddressInfo info : addresses) {
+            if (info.getExpirationTime() > now) {
+                newAddrs.add(info);
+            }
+        }
+
+        if (newAddrs.size() == 0) {
+            return null;
+        }
+        return new TetheredClient(client.getMacAddress(), newAddrs, client.getTetheringType());
+    }
+
+    @NonNull
+    private static Set<MacAddress> getClientMacs(@NonNull List<WifiClient> clients) {
+        final Set<MacAddress> macs = new HashSet<>(clients.size());
+        for (WifiClient c : clients) {
+            macs.add(c.getMacAddress());
+        }
+        return macs;
+    }
+}
diff --git a/Tethering/src/com/android/networkstack/tethering/EntitlementManager.java b/Tethering/src/com/android/networkstack/tethering/EntitlementManager.java
new file mode 100644
index 0000000..bb7322f
--- /dev/null
+++ b/Tethering/src/com/android/networkstack/tethering/EntitlementManager.java
@@ -0,0 +1,646 @@
+/*
+ * Copyright (C) 2018 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.android.networkstack.tethering;
+
+import static android.net.TetheringConstants.EXTRA_ADD_TETHER_TYPE;
+import static android.net.TetheringConstants.EXTRA_PROVISION_CALLBACK;
+import static android.net.TetheringConstants.EXTRA_RUN_PROVISION;
+import static android.net.TetheringConstants.EXTRA_TETHER_PROVISIONING_RESPONSE;
+import static android.net.TetheringConstants.EXTRA_TETHER_SILENT_PROVISIONING_ACTION;
+import static android.net.TetheringConstants.EXTRA_TETHER_SUBID;
+import static android.net.TetheringConstants.EXTRA_TETHER_UI_PROVISIONING_APP_NAME;
+import static android.net.TetheringManager.TETHERING_BLUETOOTH;
+import static android.net.TetheringManager.TETHERING_ETHERNET;
+import static android.net.TetheringManager.TETHERING_INVALID;
+import static android.net.TetheringManager.TETHERING_USB;
+import static android.net.TetheringManager.TETHERING_WIFI;
+import static android.net.TetheringManager.TETHER_ERROR_ENTITLEMENT_UNKNOWN;
+import static android.net.TetheringManager.TETHER_ERROR_NO_ERROR;
+import static android.net.TetheringManager.TETHER_ERROR_PROVISIONING_FAILED;
+
+import android.app.AlarmManager;
+import android.app.PendingIntent;
+import android.content.BroadcastReceiver;
+import android.content.ComponentName;
+import android.content.Context;
+import android.content.Intent;
+import android.content.IntentFilter;
+import android.net.util.SharedLog;
+import android.os.Bundle;
+import android.os.ConditionVariable;
+import android.os.Handler;
+import android.os.Parcel;
+import android.os.PersistableBundle;
+import android.os.ResultReceiver;
+import android.os.SystemClock;
+import android.os.SystemProperties;
+import android.provider.Settings;
+import android.telephony.CarrierConfigManager;
+import android.util.SparseIntArray;
+
+import com.android.internal.annotations.VisibleForTesting;
+
+import java.io.PrintWriter;
+import java.util.BitSet;
+
+/**
+ * Re-check tethering provisioning for enabled downstream tether types.
+ * Reference TetheringManager.TETHERING_{@code *} for each tether type.
+ *
+ * All methods of this class must be accessed from the thread of tethering
+ * state machine.
+ * @hide
+ */
+public class EntitlementManager {
+    private static final String TAG = EntitlementManager.class.getSimpleName();
+    private static final boolean DBG = false;
+
+    @VisibleForTesting
+    protected static final String DISABLE_PROVISIONING_SYSPROP_KEY = "net.tethering.noprovisioning";
+    private static final String ACTION_PROVISIONING_ALARM =
+            "com.android.networkstack.tethering.PROVISIONING_RECHECK_ALARM";
+
+    private final ComponentName mSilentProvisioningService;
+    private static final int MS_PER_HOUR = 60 * 60 * 1000;
+    private static final int DUMP_TIMEOUT = 10_000;
+
+    // The BitSet is the bit map of each enabled downstream types, ex:
+    // {@link TetheringManager.TETHERING_WIFI}
+    // {@link TetheringManager.TETHERING_USB}
+    // {@link TetheringManager.TETHERING_BLUETOOTH}
+    private final BitSet mCurrentDownstreams;
+    private final BitSet mExemptedDownstreams;
+    private final Context mContext;
+    private final SharedLog mLog;
+    private final SparseIntArray mEntitlementCacheValue;
+    private final Handler mHandler;
+    // Key: TetheringManager.TETHERING_*(downstream).
+    // Value: TetheringManager.TETHER_ERROR_{NO_ERROR or PROVISION_FAILED}(provisioning result).
+    private final SparseIntArray mCurrentEntitlementResults;
+    private final Runnable mPermissionChangeCallback;
+    private PendingIntent mProvisioningRecheckAlarm;
+    private boolean mLastCellularUpstreamPermitted = true;
+    private boolean mUsingCellularAsUpstream = false;
+    private boolean mNeedReRunProvisioningUi = false;
+    private OnUiEntitlementFailedListener mListener;
+    private TetheringConfigurationFetcher mFetcher;
+
+    public EntitlementManager(Context ctx, Handler h, SharedLog log,
+            Runnable callback) {
+        mContext = ctx;
+        mLog = log.forSubComponent(TAG);
+        mCurrentDownstreams = new BitSet();
+        mExemptedDownstreams = new BitSet();
+        mCurrentEntitlementResults = new SparseIntArray();
+        mEntitlementCacheValue = new SparseIntArray();
+        mPermissionChangeCallback = callback;
+        mHandler = h;
+        mContext.registerReceiver(mReceiver, new IntentFilter(ACTION_PROVISIONING_ALARM),
+                null, mHandler);
+        mSilentProvisioningService = ComponentName.unflattenFromString(
+                mContext.getResources().getString(R.string.config_wifi_tether_enable));
+    }
+
+    public void setOnUiEntitlementFailedListener(final OnUiEntitlementFailedListener listener) {
+        mListener = listener;
+    }
+
+    /** Callback fired when UI entitlement failed. */
+    public interface OnUiEntitlementFailedListener {
+        /**
+         * Ui entitlement check fails in |downstream|.
+         *
+         * @param downstream tethering type from TetheringManager.TETHERING_{@code *}.
+         */
+        void onUiEntitlementFailed(int downstream);
+    }
+
+    public void setTetheringConfigurationFetcher(final TetheringConfigurationFetcher fetcher) {
+        mFetcher = fetcher;
+    }
+
+    /** Interface to fetch TetheringConfiguration. */
+    public interface TetheringConfigurationFetcher {
+        /**
+         * Fetch current tethering configuration. This will be called to ensure whether entitlement
+         * check is needed.
+         * @return TetheringConfiguration instance.
+         */
+        TetheringConfiguration fetchTetheringConfiguration();
+    }
+
+    /**
+     * Check if cellular upstream is permitted.
+     */
+    public boolean isCellularUpstreamPermitted() {
+        final TetheringConfiguration config = mFetcher.fetchTetheringConfiguration();
+
+        return isCellularUpstreamPermitted(config);
+    }
+
+    private boolean isCellularUpstreamPermitted(final TetheringConfiguration config) {
+        if (!isTetherProvisioningRequired(config)) return true;
+
+        // If provisioning is required and EntitlementManager doesn't know any downstreams, cellular
+        // upstream should not be enabled. Enable cellular upstream for exempted downstreams only
+        // when there is no non-exempted downstream.
+        if (mCurrentDownstreams.isEmpty()) return !mExemptedDownstreams.isEmpty();
+
+        return mCurrentEntitlementResults.indexOfValue(TETHER_ERROR_NO_ERROR) > -1;
+    }
+
+    /**
+     * Set exempted downstream type. If there is only exempted downstream type active,
+     * corresponding entitlement check will not be run and cellular upstream will be permitted
+     * by default. If a privileged app enables tethering without a provisioning check, and then
+     * another app enables tethering of the same type but does not disable the provisioning check,
+     * then the downstream immediately loses exempt status and a provisioning check is run.
+     * If any non-exempted downstream type is active, the cellular upstream will be gated by the
+     * result of entitlement check from non-exempted downstreams. If entitlement check is still
+     * in progress on non-exempt downstreams, ceullar upstream would default be disabled. When any
+     * non-exempted downstream gets positive entitlement result, ceullar upstream will be enabled.
+     */
+    public void setExemptedDownstreamType(final int type) {
+        mExemptedDownstreams.set(type, true);
+    }
+
+    /**
+     * This is called when tethering starts.
+     * Launch provisioning app if upstream is cellular.
+     *
+     * @param downstreamType tethering type from TetheringManager.TETHERING_{@code *}
+     * @param showProvisioningUi a boolean indicating whether to show the
+     *        provisioning app UI if there is one.
+     */
+    public void startProvisioningIfNeeded(int downstreamType, boolean showProvisioningUi) {
+        if (!isValidDownstreamType(downstreamType)) return;
+
+        mCurrentDownstreams.set(downstreamType, true);
+
+        mExemptedDownstreams.set(downstreamType, false);
+
+        final TetheringConfiguration config = mFetcher.fetchTetheringConfiguration();
+        if (!isTetherProvisioningRequired(config)) return;
+
+        // If upstream is not cellular, provisioning app would not be launched
+        // till upstream change to cellular.
+        if (mUsingCellularAsUpstream) {
+            if (showProvisioningUi) {
+                runUiTetherProvisioning(downstreamType, config);
+            } else {
+                runSilentTetherProvisioning(downstreamType, config);
+            }
+            mNeedReRunProvisioningUi = false;
+        } else {
+            mNeedReRunProvisioningUi |= showProvisioningUi;
+        }
+    }
+
+    /**
+     * Tell EntitlementManager that a given type of tethering has been disabled
+     *
+     * @param type tethering type from TetheringManager.TETHERING_{@code *}
+     */
+    public void stopProvisioningIfNeeded(int downstreamType) {
+        if (!isValidDownstreamType(downstreamType)) return;
+
+        mCurrentDownstreams.set(downstreamType, false);
+        // There are lurking bugs where the notion of "provisioning required" or
+        // "tethering supported" may change without without tethering being notified properly.
+        // Remove the mapping all the time no matter provisioning is required or not.
+        removeDownstreamMapping(downstreamType);
+        mExemptedDownstreams.set(downstreamType, false);
+    }
+
+    /**
+     * Notify EntitlementManager if upstream is cellular or not.
+     *
+     * @param isCellular whether tethering upstream is cellular.
+     */
+    public void notifyUpstream(boolean isCellular) {
+        if (DBG) {
+            mLog.i("notifyUpstream: " + isCellular
+                    + ", mLastCellularUpstreamPermitted: " + mLastCellularUpstreamPermitted
+                    + ", mNeedReRunProvisioningUi: " + mNeedReRunProvisioningUi);
+        }
+        mUsingCellularAsUpstream = isCellular;
+
+        if (mUsingCellularAsUpstream) {
+            final TetheringConfiguration config = mFetcher.fetchTetheringConfiguration();
+            maybeRunProvisioning(config);
+        }
+    }
+
+    /** Run provisioning if needed */
+    public void maybeRunProvisioning() {
+        final TetheringConfiguration config = mFetcher.fetchTetheringConfiguration();
+        maybeRunProvisioning(config);
+    }
+
+    private void maybeRunProvisioning(final TetheringConfiguration config) {
+        if (mCurrentDownstreams.isEmpty() || !isTetherProvisioningRequired(config)) {
+            return;
+        }
+
+        // Whenever any entitlement value changes, all downstreams will re-evaluate whether they
+        // are allowed. Therefore even if the silent check here ends in a failure and the UI later
+        // yields success, then the downstream that got a failure will re-evaluate as a result of
+        // the change and get the new correct value.
+        for (int downstream = mCurrentDownstreams.nextSetBit(0); downstream >= 0;
+                downstream = mCurrentDownstreams.nextSetBit(downstream + 1)) {
+            if (mCurrentEntitlementResults.indexOfKey(downstream) < 0) {
+                if (mNeedReRunProvisioningUi) {
+                    mNeedReRunProvisioningUi = false;
+                    runUiTetherProvisioning(downstream, config);
+                } else {
+                    runSilentTetherProvisioning(downstream, config);
+                }
+            }
+        }
+    }
+
+    /**
+     * Check if the device requires a provisioning check in order to enable tethering.
+     *
+     * @param config an object that encapsulates the various tethering configuration elements.
+     * @return a boolean - {@code true} indicating tether provisioning is required by the carrier.
+     */
+    @VisibleForTesting
+    protected boolean isTetherProvisioningRequired(final TetheringConfiguration config) {
+        if (SystemProperties.getBoolean(DISABLE_PROVISIONING_SYSPROP_KEY, false)
+                || config.provisioningApp.length == 0) {
+            return false;
+        }
+        if (carrierConfigAffirmsEntitlementCheckNotRequired(config)) {
+            return false;
+        }
+        return (config.provisioningApp.length == 2);
+    }
+
+    /**
+     * Re-check tethering provisioning for all enabled tether types.
+     * Reference TetheringManager.TETHERING_{@code *} for each tether type.
+     *
+     * @param config an object that encapsulates the various tethering configuration elements.
+     * Note: this method is only called from @{link Tethering.TetherMainSM} on the handler thread.
+     * If there are new callers from different threads, the logic should move to
+     * @{link Tethering.TetherMainSM} handler to avoid race conditions.
+     */
+    public void reevaluateSimCardProvisioning(final TetheringConfiguration config) {
+        if (DBG) mLog.i("reevaluateSimCardProvisioning");
+
+        if (!mHandler.getLooper().isCurrentThread()) {
+            // Except for test, this log should not appear in normal flow.
+            mLog.log("reevaluateSimCardProvisioning() don't run in TetherMainSM thread");
+        }
+        mEntitlementCacheValue.clear();
+        mCurrentEntitlementResults.clear();
+
+        // TODO: refine provisioning check to isTetherProvisioningRequired() ??
+        if (!config.hasMobileHotspotProvisionApp()
+                || carrierConfigAffirmsEntitlementCheckNotRequired(config)) {
+            evaluateCellularPermission(config);
+            return;
+        }
+
+        if (mUsingCellularAsUpstream) {
+            maybeRunProvisioning(config);
+        }
+    }
+
+    /**
+     * Get carrier configuration bundle.
+     * @param config an object that encapsulates the various tethering configuration elements.
+     * */
+    public PersistableBundle getCarrierConfig(final TetheringConfiguration config) {
+        final CarrierConfigManager configManager = (CarrierConfigManager) mContext
+                .getSystemService(Context.CARRIER_CONFIG_SERVICE);
+        if (configManager == null) return null;
+
+        final PersistableBundle carrierConfig = configManager.getConfigForSubId(
+                config.activeDataSubId);
+
+        if (CarrierConfigManager.isConfigForIdentifiedCarrier(carrierConfig)) {
+            return carrierConfig;
+        }
+
+        return null;
+    }
+
+    // The logic here is aimed solely at confirming that a CarrierConfig exists
+    // and affirms that entitlement checks are not required.
+    //
+    // TODO: find a better way to express this, or alter the checking process
+    // entirely so that this is more intuitive.
+    private boolean carrierConfigAffirmsEntitlementCheckNotRequired(
+            final TetheringConfiguration config) {
+        // Check carrier config for entitlement checks
+        final PersistableBundle carrierConfig = getCarrierConfig(config);
+        if (carrierConfig == null) return false;
+
+        // A CarrierConfigManager was found and it has a config.
+        final boolean isEntitlementCheckRequired = carrierConfig.getBoolean(
+                CarrierConfigManager.KEY_REQUIRE_ENTITLEMENT_CHECKS_BOOL);
+        return !isEntitlementCheckRequired;
+    }
+
+    /**
+     * Run no UI tethering provisioning check.
+     * @param type tethering type from TetheringManager.TETHERING_{@code *}
+     * @param subId default data subscription ID.
+     */
+    @VisibleForTesting
+    protected Intent runSilentTetherProvisioning(int type, final TetheringConfiguration config) {
+        if (DBG) mLog.i("runSilentTetherProvisioning: " + type);
+        // For silent provisioning, settings would stop tethering when entitlement fail.
+        ResultReceiver receiver = buildProxyReceiver(type, false/* notifyFail */, null);
+
+        Intent intent = new Intent();
+        intent.putExtra(EXTRA_ADD_TETHER_TYPE, type);
+        intent.putExtra(EXTRA_RUN_PROVISION, true);
+        intent.putExtra(EXTRA_TETHER_SILENT_PROVISIONING_ACTION, config.provisioningAppNoUi);
+        intent.putExtra(EXTRA_TETHER_PROVISIONING_RESPONSE, config.provisioningResponse);
+        intent.putExtra(EXTRA_PROVISION_CALLBACK, receiver);
+        intent.putExtra(EXTRA_TETHER_SUBID, config.activeDataSubId);
+        intent.setComponent(mSilentProvisioningService);
+        // Only admin user can change tethering and SilentTetherProvisioning don't need to
+        // show UI, it is fine to always start setting's background service as system user.
+        mContext.startService(intent);
+        return intent;
+    }
+
+    private void runUiTetherProvisioning(int type, final TetheringConfiguration config) {
+        ResultReceiver receiver = buildProxyReceiver(type, true/* notifyFail */, null);
+        runUiTetherProvisioning(type, config, receiver);
+    }
+
+    /**
+     * Run the UI-enabled tethering provisioning check.
+     * @param type tethering type from TetheringManager.TETHERING_{@code *}
+     * @param subId default data subscription ID.
+     * @param receiver to receive entitlement check result.
+     */
+    @VisibleForTesting
+    protected Intent runUiTetherProvisioning(int type, final TetheringConfiguration config,
+            ResultReceiver receiver) {
+        if (DBG) mLog.i("runUiTetherProvisioning: " + type);
+
+        Intent intent = new Intent(Settings.ACTION_TETHER_PROVISIONING_UI);
+        intent.putExtra(EXTRA_ADD_TETHER_TYPE, type);
+        intent.putExtra(EXTRA_TETHER_UI_PROVISIONING_APP_NAME, config.provisioningApp);
+        intent.putExtra(EXTRA_PROVISION_CALLBACK, receiver);
+        intent.putExtra(EXTRA_TETHER_SUBID, config.activeDataSubId);
+        intent.addFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
+        // Only launch entitlement UI for system user. Entitlement UI should not appear for other
+        // user because only admin user is allowed to change tethering.
+        mContext.startActivity(intent);
+        return intent;
+    }
+
+    // Not needed to check if this don't run on the handler thread because it's private.
+    private void scheduleProvisioningRechecks(final TetheringConfiguration config) {
+        if (mProvisioningRecheckAlarm == null) {
+            final int period = config.provisioningCheckPeriod;
+            if (period <= 0) return;
+
+            Intent intent = new Intent(ACTION_PROVISIONING_ALARM);
+            mProvisioningRecheckAlarm = PendingIntent.getBroadcast(mContext, 0, intent, 0);
+            AlarmManager alarmManager = (AlarmManager) mContext.getSystemService(
+                    Context.ALARM_SERVICE);
+            long periodMs = period * MS_PER_HOUR;
+            long firstAlarmTime = SystemClock.elapsedRealtime() + periodMs;
+            alarmManager.setRepeating(AlarmManager.ELAPSED_REALTIME, firstAlarmTime, periodMs,
+                    mProvisioningRecheckAlarm);
+        }
+    }
+
+    private void cancelTetherProvisioningRechecks() {
+        if (mProvisioningRecheckAlarm != null) {
+            AlarmManager alarmManager = (AlarmManager) mContext.getSystemService(
+                    Context.ALARM_SERVICE);
+            alarmManager.cancel(mProvisioningRecheckAlarm);
+            mProvisioningRecheckAlarm = null;
+        }
+    }
+
+    private void evaluateCellularPermission(final TetheringConfiguration config) {
+        final boolean permitted = isCellularUpstreamPermitted(config);
+
+        if (DBG) {
+            mLog.i("Cellular permission change from " + mLastCellularUpstreamPermitted
+                    + " to " + permitted);
+        }
+
+        if (mLastCellularUpstreamPermitted != permitted) {
+            mLog.log("Cellular permission change: " + permitted);
+            mPermissionChangeCallback.run();
+        }
+        // Only schedule periodic re-check when tether is provisioned
+        // and the result is ok.
+        if (permitted && mCurrentEntitlementResults.size() > 0) {
+            scheduleProvisioningRechecks(config);
+        } else {
+            cancelTetherProvisioningRechecks();
+        }
+        mLastCellularUpstreamPermitted = permitted;
+    }
+
+    /**
+     * Add the mapping between provisioning result and tethering type.
+     * Notify UpstreamNetworkMonitor if Cellular permission changes.
+     *
+     * @param type tethering type from TetheringManager.TETHERING_{@code *}
+     * @param resultCode Provisioning result
+     */
+    protected void addDownstreamMapping(int type, int resultCode) {
+        mLog.i("addDownstreamMapping: " + type + ", result: " + resultCode
+                + " ,TetherTypeRequested: " + mCurrentDownstreams.get(type));
+        if (!mCurrentDownstreams.get(type)) return;
+
+        mCurrentEntitlementResults.put(type, resultCode);
+        final TetheringConfiguration config = mFetcher.fetchTetheringConfiguration();
+        evaluateCellularPermission(config);
+    }
+
+    /**
+     * Remove the mapping for input tethering type.
+     * @param type tethering type from TetheringManager.TETHERING_{@code *}
+     */
+    protected void removeDownstreamMapping(int type) {
+        mLog.i("removeDownstreamMapping: " + type);
+        mCurrentEntitlementResults.delete(type);
+        final TetheringConfiguration config = mFetcher.fetchTetheringConfiguration();
+        evaluateCellularPermission(config);
+    }
+
+    private final BroadcastReceiver mReceiver = new BroadcastReceiver() {
+        @Override
+        public void onReceive(Context context, Intent intent) {
+            if (ACTION_PROVISIONING_ALARM.equals(intent.getAction())) {
+                mLog.log("Received provisioning alarm");
+                final TetheringConfiguration config = mFetcher.fetchTetheringConfiguration();
+                reevaluateSimCardProvisioning(config);
+            }
+        }
+    };
+
+    private static boolean isValidDownstreamType(int type) {
+        switch (type) {
+            case TETHERING_BLUETOOTH:
+            case TETHERING_ETHERNET:
+            case TETHERING_USB:
+            case TETHERING_WIFI:
+                return true;
+            default:
+                return false;
+        }
+    }
+
+    /**
+     * Dump the infromation of EntitlementManager.
+     * @param pw {@link PrintWriter} is used to print formatted
+     */
+    public void dump(PrintWriter pw) {
+        final ConditionVariable mWaiting = new ConditionVariable();
+        mHandler.post(() -> {
+            pw.print("isCellularUpstreamPermitted: ");
+            pw.println(isCellularUpstreamPermitted());
+            for (int type = mCurrentDownstreams.nextSetBit(0); type >= 0;
+                    type = mCurrentDownstreams.nextSetBit(type + 1)) {
+                pw.print("Type: ");
+                pw.print(typeString(type));
+                if (mCurrentEntitlementResults.indexOfKey(type) > -1) {
+                    pw.print(", Value: ");
+                    pw.println(errorString(mCurrentEntitlementResults.get(type)));
+                } else {
+                    pw.println(", Value: empty");
+                }
+            }
+            mWaiting.open();
+        });
+        if (!mWaiting.block(DUMP_TIMEOUT)) {
+            pw.println("... dump timed out after " + DUMP_TIMEOUT + "ms");
+        }
+        pw.print("Exempted: [");
+        for (int type = mExemptedDownstreams.nextSetBit(0); type >= 0;
+                type = mExemptedDownstreams.nextSetBit(type + 1)) {
+            pw.print(typeString(type));
+            pw.print(", ");
+        }
+        pw.println("]");
+    }
+
+    private static String typeString(int type) {
+        switch (type) {
+            case TETHERING_BLUETOOTH: return "TETHERING_BLUETOOTH";
+            case TETHERING_INVALID: return "TETHERING_INVALID";
+            case TETHERING_USB: return "TETHERING_USB";
+            case TETHERING_WIFI: return "TETHERING_WIFI";
+            default:
+                return String.format("TETHERING UNKNOWN TYPE (%d)", type);
+        }
+    }
+
+    private static String errorString(int value) {
+        switch (value) {
+            case TETHER_ERROR_ENTITLEMENT_UNKNOWN: return "TETHER_ERROR_ENTITLEMENT_UNKONWN";
+            case TETHER_ERROR_NO_ERROR: return "TETHER_ERROR_NO_ERROR";
+            case TETHER_ERROR_PROVISIONING_FAILED: return "TETHER_ERROR_PROVISIONING_FAILED";
+            default:
+                return String.format("UNKNOWN ERROR (%d)", value);
+        }
+    }
+
+    private ResultReceiver buildProxyReceiver(int type, boolean notifyFail,
+            final ResultReceiver receiver) {
+        ResultReceiver rr = new ResultReceiver(mHandler) {
+            @Override
+            protected void onReceiveResult(int resultCode, Bundle resultData) {
+                int updatedCacheValue = updateEntitlementCacheValue(type, resultCode);
+                addDownstreamMapping(type, updatedCacheValue);
+                if (updatedCacheValue == TETHER_ERROR_PROVISIONING_FAILED && notifyFail) {
+                    mListener.onUiEntitlementFailed(type);
+                }
+                if (receiver != null) receiver.send(updatedCacheValue, null);
+            }
+        };
+
+        return writeToParcel(rr);
+    }
+
+    // Instances of ResultReceiver need to be public classes for remote processes to be able
+    // to load them (otherwise, ClassNotFoundException). For private classes, this method
+    // performs a trick : round-trip parceling any instance of ResultReceiver will return a
+    // vanilla instance of ResultReceiver sharing the binder token with the original receiver.
+    // The binder token has a reference to the original instance of the private class and will
+    // still call its methods, and can be sent over. However it cannot be used for anything
+    // else than sending over a Binder call.
+    // While round-trip parceling is not great, there is currently no other way of generating
+    // a vanilla instance of ResultReceiver because all its fields are private.
+    private ResultReceiver writeToParcel(final ResultReceiver receiver) {
+        Parcel parcel = Parcel.obtain();
+        receiver.writeToParcel(parcel, 0);
+        parcel.setDataPosition(0);
+        ResultReceiver receiverForSending = ResultReceiver.CREATOR.createFromParcel(parcel);
+        parcel.recycle();
+        return receiverForSending;
+    }
+
+    /**
+     * Update the last entitlement value to internal cache
+     *
+     * @param type tethering type from TetheringManager.TETHERING_{@code *}
+     * @param resultCode last entitlement value
+     * @return the last updated entitlement value
+     */
+    private int updateEntitlementCacheValue(int type, int resultCode) {
+        if (DBG) {
+            mLog.i("updateEntitlementCacheValue: " + type + ", result: " + resultCode);
+        }
+        if (resultCode == TETHER_ERROR_NO_ERROR) {
+            mEntitlementCacheValue.put(type, resultCode);
+            return resultCode;
+        } else {
+            mEntitlementCacheValue.put(type, TETHER_ERROR_PROVISIONING_FAILED);
+            return TETHER_ERROR_PROVISIONING_FAILED;
+        }
+    }
+
+    /** Get the last value of the tethering entitlement check. */
+    public void requestLatestTetheringEntitlementResult(int downstream, ResultReceiver receiver,
+            boolean showEntitlementUi) {
+        if (!isValidDownstreamType(downstream)) {
+            receiver.send(TETHER_ERROR_ENTITLEMENT_UNKNOWN, null);
+            return;
+        }
+
+        final TetheringConfiguration config = mFetcher.fetchTetheringConfiguration();
+        if (!isTetherProvisioningRequired(config)) {
+            receiver.send(TETHER_ERROR_NO_ERROR, null);
+            return;
+        }
+
+        final int cacheValue = mEntitlementCacheValue.get(
+                downstream, TETHER_ERROR_ENTITLEMENT_UNKNOWN);
+        if (cacheValue == TETHER_ERROR_NO_ERROR || !showEntitlementUi) {
+            receiver.send(cacheValue, null);
+        } else {
+            ResultReceiver proxy = buildProxyReceiver(downstream, false/* notifyFail */, receiver);
+            runUiTetherProvisioning(downstream, config, proxy);
+        }
+    }
+}
diff --git a/Tethering/src/com/android/networkstack/tethering/IPv6TetheringCoordinator.java b/Tethering/src/com/android/networkstack/tethering/IPv6TetheringCoordinator.java
new file mode 100644
index 0000000..f3dcaa2
--- /dev/null
+++ b/Tethering/src/com/android/networkstack/tethering/IPv6TetheringCoordinator.java
@@ -0,0 +1,328 @@
+/*
+ * Copyright (C) 2016 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.android.networkstack.tethering;
+
+import android.net.IpPrefix;
+import android.net.LinkAddress;
+import android.net.LinkProperties;
+import android.net.Network;
+import android.net.NetworkCapabilities;
+import android.net.RouteInfo;
+import android.net.ip.IpServer;
+import android.net.util.NetworkConstants;
+import android.net.util.SharedLog;
+import android.util.Log;
+
+import java.net.Inet6Address;
+import java.net.InetAddress;
+import java.net.UnknownHostException;
+import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.LinkedList;
+import java.util.Random;
+
+
+/**
+ * IPv6 tethering is rather different from IPv4 owing to the absence of NAT.
+ * This coordinator is responsible for evaluating the dedicated prefixes
+ * assigned to the device and deciding how to divvy them up among downstream
+ * interfaces.
+ *
+ * @hide
+ */
+public class IPv6TetheringCoordinator {
+    private static final String TAG = IPv6TetheringCoordinator.class.getSimpleName();
+    private static final boolean DBG = false;
+    private static final boolean VDBG = false;
+
+    private static class Downstream {
+        public final IpServer ipServer;
+        public final int mode;  // IpServer.STATE_*
+        // Used to append to a ULA /48, constructing a ULA /64 for local use.
+        public final short subnetId;
+
+        Downstream(IpServer ipServer, int mode, short subnetId) {
+            this.ipServer = ipServer;
+            this.mode = mode;
+            this.subnetId = subnetId;
+        }
+    }
+
+    private final ArrayList<IpServer> mNotifyList;
+    private final SharedLog mLog;
+    // NOTE: mActiveDownstreams is a list and not a hash data structure because
+    // we keep active downstreams in arrival order.  This is done so /64s can
+    // be parceled out on a "first come, first served" basis and a /64 used by
+    // a downstream that is no longer active can be redistributed to any next
+    // waiting active downstream (again, in arrival order).
+    private final LinkedList<Downstream> mActiveDownstreams;
+    private final byte[] mUniqueLocalPrefix;
+    private short mNextSubnetId;
+    private UpstreamNetworkState mUpstreamNetworkState;
+
+    public IPv6TetheringCoordinator(ArrayList<IpServer> notifyList, SharedLog log) {
+        mNotifyList = notifyList;
+        mLog = log.forSubComponent(TAG);
+        mActiveDownstreams = new LinkedList<>();
+        mUniqueLocalPrefix = generateUniqueLocalPrefix();
+        mNextSubnetId = 0;
+    }
+
+    /** Add active downstream to ipv6 tethering candidate list. */
+    public void addActiveDownstream(IpServer downstream, int mode) {
+        if (findDownstream(downstream) == null) {
+            // Adding a new downstream appends it to the list. Adding a
+            // downstream a second time without first removing it has no effect.
+            // We never change the mode of a downstream except by first removing
+            // it and then re-adding it (with its new mode specified);
+            if (mActiveDownstreams.offer(new Downstream(downstream, mode, mNextSubnetId))) {
+                // Make sure subnet IDs are always positive. They are appended
+                // to a ULA /48 to make a ULA /64 for local use.
+                mNextSubnetId = (short) Math.max(0, mNextSubnetId + 1);
+            }
+            updateIPv6TetheringInterfaces();
+        }
+    }
+
+    /** Remove downstream from ipv6 tethering candidate list. */
+    public void removeActiveDownstream(IpServer downstream) {
+        stopIPv6TetheringOn(downstream);
+        if (mActiveDownstreams.remove(findDownstream(downstream))) {
+            updateIPv6TetheringInterfaces();
+        }
+
+        // When tethering is stopping we can reset the subnet counter.
+        if (mNotifyList.isEmpty()) {
+            if (!mActiveDownstreams.isEmpty()) {
+                Log.wtf(TAG, "Tethering notify list empty, IPv6 downstreams non-empty.");
+            }
+            mNextSubnetId = 0;
+        }
+    }
+
+    /**
+     * Call when UpstreamNetworkState may be changed.
+     * If upstream has ipv6 for tethering, update this new UpstreamNetworkState
+     * to IpServer. Otherwise stop ipv6 tethering on downstream interfaces.
+     */
+    public void updateUpstreamNetworkState(UpstreamNetworkState ns) {
+        if (VDBG) {
+            Log.d(TAG, "updateUpstreamNetworkState: " + toDebugString(ns));
+        }
+        if (TetheringInterfaceUtils.getIPv6Interface(ns) == null) {
+            stopIPv6TetheringOnAllInterfaces();
+            setUpstreamNetworkState(null);
+            return;
+        }
+
+        if (mUpstreamNetworkState != null
+                && !ns.network.equals(mUpstreamNetworkState.network)) {
+            stopIPv6TetheringOnAllInterfaces();
+        }
+
+        setUpstreamNetworkState(ns);
+        updateIPv6TetheringInterfaces();
+    }
+
+    private void stopIPv6TetheringOnAllInterfaces() {
+        for (IpServer ipServer : mNotifyList) {
+            stopIPv6TetheringOn(ipServer);
+        }
+    }
+
+    private void setUpstreamNetworkState(UpstreamNetworkState ns) {
+        if (ns == null) {
+            mUpstreamNetworkState = null;
+        } else {
+            // Make a deep copy of the parts we need.
+            mUpstreamNetworkState = new UpstreamNetworkState(
+                    new LinkProperties(ns.linkProperties),
+                    new NetworkCapabilities(ns.networkCapabilities),
+                    new Network(ns.network));
+        }
+
+        mLog.log("setUpstreamNetworkState: " + toDebugString(mUpstreamNetworkState));
+    }
+
+    private void updateIPv6TetheringInterfaces() {
+        for (IpServer ipServer : mNotifyList) {
+            final LinkProperties lp = getInterfaceIPv6LinkProperties(ipServer);
+            ipServer.sendMessage(IpServer.CMD_IPV6_TETHER_UPDATE, getTtlAdjustment(), 0, lp);
+            break;
+        }
+    }
+
+    private int getTtlAdjustment() {
+        if (mUpstreamNetworkState == null || mUpstreamNetworkState.networkCapabilities == null) {
+            return 0;
+        }
+
+        // If upstream is cellular, set the TTL in Router Advertisements to "network-set TTL" - 1
+        // for carrier requirement.
+        if (mUpstreamNetworkState.networkCapabilities.hasTransport(
+                NetworkCapabilities.TRANSPORT_CELLULAR)) {
+            return -1;
+        }
+
+        // For other non-cellular upstream, set TTL as "network-set TTL" + 1 to preventing arbitrary
+        // distinction between tethered and untethered traffic.
+        return 1;
+    }
+
+    private LinkProperties getInterfaceIPv6LinkProperties(IpServer ipServer) {
+        final Downstream ds = findDownstream(ipServer);
+        if (ds == null) return null;
+
+        if (ds.mode == IpServer.STATE_LOCAL_ONLY) {
+            // Build a Unique Locally-assigned Prefix configuration.
+            return getUniqueLocalConfig(mUniqueLocalPrefix, ds.subnetId);
+        }
+
+        // This downstream is in IpServer.STATE_TETHERED mode.
+        if (mUpstreamNetworkState == null || mUpstreamNetworkState.linkProperties == null) {
+            return null;
+        }
+
+        // NOTE: Here, in future, we would have policies to decide how to divvy
+        // up the available dedicated prefixes among downstream interfaces.
+        // At this time we have no such mechanism--we only support tethering
+        // IPv6 toward the oldest (first requested) active downstream.
+
+        final Downstream currentActive = mActiveDownstreams.peek();
+        if (currentActive != null && currentActive.ipServer == ipServer) {
+            final LinkProperties lp = getIPv6OnlyLinkProperties(
+                    mUpstreamNetworkState.linkProperties);
+            if (lp.hasIpv6DefaultRoute() && lp.hasGlobalIpv6Address()) {
+                return lp;
+            }
+        }
+
+        return null;
+    }
+
+    Downstream findDownstream(IpServer ipServer) {
+        for (Downstream ds : mActiveDownstreams) {
+            if (ds.ipServer == ipServer) return ds;
+        }
+        return null;
+    }
+
+    private static LinkProperties getIPv6OnlyLinkProperties(LinkProperties lp) {
+        final LinkProperties v6only = new LinkProperties();
+        if (lp == null) {
+            return v6only;
+        }
+
+        // NOTE: At this time we don't copy over any information about any
+        // stacked links. No current stacked link configuration has IPv6.
+
+        v6only.setInterfaceName(lp.getInterfaceName());
+
+        v6only.setMtu(lp.getMtu());
+
+        for (LinkAddress linkAddr : lp.getLinkAddresses()) {
+            if (linkAddr.isGlobalPreferred() && linkAddr.getPrefixLength() == 64) {
+                v6only.addLinkAddress(linkAddr);
+            }
+        }
+
+        for (RouteInfo routeInfo : lp.getRoutes()) {
+            final IpPrefix destination = routeInfo.getDestination();
+            if ((destination.getAddress() instanceof Inet6Address)
+                    && (destination.getPrefixLength() <= 64)) {
+                v6only.addRoute(routeInfo);
+            }
+        }
+
+        for (InetAddress dnsServer : lp.getDnsServers()) {
+            if (isIPv6GlobalAddress(dnsServer)) {
+                // For now we include ULAs.
+                v6only.addDnsServer(dnsServer);
+            }
+        }
+
+        v6only.setDomains(lp.getDomains());
+
+        return v6only;
+    }
+
+    // TODO: Delete this and switch to LinkAddress#isGlobalPreferred once we
+    // announce our own IPv6 address as DNS server.
+    private static boolean isIPv6GlobalAddress(InetAddress ip) {
+        return (ip instanceof Inet6Address)
+               && !ip.isAnyLocalAddress()
+               && !ip.isLoopbackAddress()
+               && !ip.isLinkLocalAddress()
+               && !ip.isSiteLocalAddress()
+               && !ip.isMulticastAddress();
+    }
+
+    private static LinkProperties getUniqueLocalConfig(byte[] ulp, short subnetId) {
+        final LinkProperties lp = new LinkProperties();
+
+        final IpPrefix local48 = makeUniqueLocalPrefix(ulp, (short) 0, 48);
+        lp.addRoute(new RouteInfo(local48, null, null, RouteInfo.RTN_UNICAST));
+
+        final IpPrefix local64 = makeUniqueLocalPrefix(ulp, subnetId, 64);
+        // Because this is a locally-generated ULA, we don't have an upstream
+        // address. But because the downstream IP address management code gets
+        // its prefix from the upstream's IP address, we create a fake one here.
+        lp.addLinkAddress(new LinkAddress(local64.getAddress(), 64));
+
+        lp.setMtu(NetworkConstants.ETHER_MTU);
+        return lp;
+    }
+
+    private static IpPrefix makeUniqueLocalPrefix(byte[] in6addr, short subnetId, int prefixlen) {
+        final byte[] bytes = Arrays.copyOf(in6addr, in6addr.length);
+        bytes[7] = (byte) (subnetId >> 8);
+        bytes[8] = (byte) subnetId;
+        final InetAddress addr;
+        try {
+            addr = InetAddress.getByAddress(bytes);
+        } catch (UnknownHostException e) {
+            throw new IllegalStateException("Invalid address length: " + bytes.length, e);
+        }
+        return new IpPrefix(addr, prefixlen);
+    }
+
+    // Generates a Unique Locally-assigned Prefix:
+    //
+    //     https://tools.ietf.org/html/rfc4193#section-3.1
+    //
+    // The result is a /48 that can be used for local-only communications.
+    private static byte[] generateUniqueLocalPrefix() {
+        final byte[] ulp = new byte[6];  // 6 = 48bits / 8bits/byte
+        (new Random()).nextBytes(ulp);
+
+        final byte[] in6addr = Arrays.copyOf(ulp, NetworkConstants.IPV6_ADDR_LEN);
+        in6addr[0] = (byte) 0xfd;  // fc00::/7 and L=1
+
+        return in6addr;
+    }
+
+    private static String toDebugString(UpstreamNetworkState ns) {
+        if (ns == null) {
+            return "UpstreamNetworkState{null}";
+        }
+        return ns.toString();
+    }
+
+    private static void stopIPv6TetheringOn(IpServer ipServer) {
+        ipServer.sendMessage(IpServer.CMD_IPV6_TETHER_UPDATE, 0, 0, null);
+    }
+}
diff --git a/Tethering/src/com/android/networkstack/tethering/OffloadController.java b/Tethering/src/com/android/networkstack/tethering/OffloadController.java
new file mode 100644
index 0000000..88c77b0
--- /dev/null
+++ b/Tethering/src/com/android/networkstack/tethering/OffloadController.java
@@ -0,0 +1,811 @@
+/*
+ * Copyright (C) 2017 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.android.networkstack.tethering;
+
+import static android.net.NetworkStats.DEFAULT_NETWORK_NO;
+import static android.net.NetworkStats.METERED_NO;
+import static android.net.NetworkStats.ROAMING_NO;
+import static android.net.NetworkStats.SET_DEFAULT;
+import static android.net.NetworkStats.TAG_NONE;
+import static android.net.NetworkStats.UID_ALL;
+import static android.net.NetworkStats.UID_TETHERING;
+import static android.net.netstats.provider.NetworkStatsProvider.QUOTA_UNLIMITED;
+import static android.provider.Settings.Global.TETHER_OFFLOAD_DISABLED;
+
+import static com.android.networkstack.tethering.TetheringConfiguration.DEFAULT_TETHER_OFFLOAD_POLL_INTERVAL_MS;
+
+import android.annotation.NonNull;
+import android.annotation.Nullable;
+import android.app.usage.NetworkStatsManager;
+import android.content.ContentResolver;
+import android.net.InetAddresses;
+import android.net.IpPrefix;
+import android.net.LinkAddress;
+import android.net.LinkProperties;
+import android.net.NetworkStats;
+import android.net.NetworkStats.Entry;
+import android.net.RouteInfo;
+import android.net.netlink.ConntrackMessage;
+import android.net.netlink.NetlinkConstants;
+import android.net.netlink.NetlinkSocket;
+import android.net.netstats.provider.NetworkStatsProvider;
+import android.net.util.SharedLog;
+import android.os.Handler;
+import android.provider.Settings;
+import android.system.ErrnoException;
+import android.system.OsConstants;
+import android.text.TextUtils;
+import android.util.Log;
+
+import com.android.internal.annotations.VisibleForTesting;
+import com.android.internal.util.IndentingPrintWriter;
+import com.android.networkstack.tethering.OffloadHardwareInterface.ForwardedStats;
+
+import java.net.Inet4Address;
+import java.net.Inet6Address;
+import java.net.InetAddress;
+import java.util.ArrayList;
+import java.util.Collections;
+import java.util.HashMap;
+import java.util.HashSet;
+import java.util.List;
+import java.util.Map;
+import java.util.Objects;
+import java.util.Set;
+import java.util.concurrent.ConcurrentHashMap;
+
+/**
+ * A class to encapsulate the business logic of programming the tethering
+ * hardware offload interface.
+ *
+ * @hide
+ */
+public class OffloadController {
+    private static final String TAG = OffloadController.class.getSimpleName();
+    private static final boolean DBG = false;
+    private static final String ANYIP = "0.0.0.0";
+    private static final ForwardedStats EMPTY_STATS = new ForwardedStats();
+
+    @VisibleForTesting
+    enum StatsType {
+        STATS_PER_IFACE,
+        STATS_PER_UID,
+    }
+
+    private enum UpdateType { IF_NEEDED, FORCE };
+
+    private final Handler mHandler;
+    private final OffloadHardwareInterface mHwInterface;
+    private final ContentResolver mContentResolver;
+    @Nullable
+    private final OffloadTetheringStatsProvider mStatsProvider;
+    private final SharedLog mLog;
+    private final HashMap<String, LinkProperties> mDownstreams;
+    private boolean mConfigInitialized;
+    private boolean mControlInitialized;
+    private LinkProperties mUpstreamLinkProperties;
+    // The complete set of offload-exempt prefixes passed in via Tethering from
+    // all upstream and downstream sources.
+    private Set<IpPrefix> mExemptPrefixes;
+    // A strictly "smaller" set of prefixes, wherein offload-approved prefixes
+    // (e.g. downstream on-link prefixes) have been removed and replaced with
+    // prefixes representing only the locally-assigned IP addresses.
+    private Set<String> mLastLocalPrefixStrs;
+
+    // Maps upstream interface names to offloaded traffic statistics.
+    // Always contains the latest value received from the hardware for each interface, regardless of
+    // whether offload is currently running on that interface.
+    private ConcurrentHashMap<String, ForwardedStats> mForwardedStats =
+            new ConcurrentHashMap<>(16, 0.75F, 1);
+
+    // Maps upstream interface names to interface quotas.
+    // Always contains the latest value received from the framework for each interface, regardless
+    // of whether offload is currently running (or is even supported) on that interface. Only
+    // includes upstream interfaces that have a quota set.
+    private HashMap<String, Long> mInterfaceQuotas = new HashMap<>();
+
+    // Tracking remaining alert quota. Unlike limit quota is subject to interface, the alert
+    // quota is interface independent and global for tether offload. Note that this is only
+    // accessed on the handler thread and in the constructor.
+    private long mRemainingAlertQuota = QUOTA_UNLIMITED;
+    // Runnable that used to schedule the next stats poll.
+    private final Runnable mScheduledPollingTask = () -> {
+        updateStatsForCurrentUpstream();
+        maybeSchedulePollingStats();
+    };
+
+    private int mNatUpdateCallbacksReceived;
+    private int mNatUpdateNetlinkErrors;
+
+    @NonNull
+    private final Dependencies mDeps;
+
+    // TODO: Put more parameters in constructor into dependency object.
+    interface Dependencies {
+        @NonNull
+        TetheringConfiguration getTetherConfig();
+    }
+
+    public OffloadController(Handler h, OffloadHardwareInterface hwi,
+            ContentResolver contentResolver, NetworkStatsManager nsm, SharedLog log,
+            @NonNull Dependencies deps) {
+        mHandler = h;
+        mHwInterface = hwi;
+        mContentResolver = contentResolver;
+        mLog = log.forSubComponent(TAG);
+        mDownstreams = new HashMap<>();
+        mExemptPrefixes = new HashSet<>();
+        mLastLocalPrefixStrs = new HashSet<>();
+        OffloadTetheringStatsProvider provider = new OffloadTetheringStatsProvider();
+        try {
+            nsm.registerNetworkStatsProvider(getClass().getSimpleName(), provider);
+        } catch (RuntimeException e) {
+            Log.wtf(TAG, "Cannot register offload stats provider: " + e);
+            provider = null;
+        }
+        mStatsProvider = provider;
+        mDeps = deps;
+    }
+
+    /** Start hardware offload. */
+    public boolean start() {
+        if (started()) return true;
+
+        if (isOffloadDisabled()) {
+            mLog.i("tethering offload disabled");
+            return false;
+        }
+
+        if (!mConfigInitialized) {
+            mConfigInitialized = mHwInterface.initOffloadConfig();
+            if (!mConfigInitialized) {
+                mLog.i("tethering offload config not supported");
+                stop();
+                return false;
+            }
+        }
+
+        mControlInitialized = mHwInterface.initOffloadControl(
+                // OffloadHardwareInterface guarantees that these callback
+                // methods are called on the handler passed to it, which is the
+                // same as mHandler, as coordinated by the setup in Tethering.
+                new OffloadHardwareInterface.ControlCallback() {
+                    @Override
+                    public void onStarted() {
+                        if (!started()) return;
+                        mLog.log("onStarted");
+                    }
+
+                    @Override
+                    public void onStoppedError() {
+                        if (!started()) return;
+                        mLog.log("onStoppedError");
+                    }
+
+                    @Override
+                    public void onStoppedUnsupported() {
+                        if (!started()) return;
+                        mLog.log("onStoppedUnsupported");
+                        // Poll for statistics and trigger a sweep of tethering
+                        // stats by observers. This might not succeed, but it's
+                        // worth trying anyway. We need to do this because from
+                        // this point on we continue with software forwarding,
+                        // and we need to synchronize stats and limits between
+                        // software and hardware forwarding.
+                        updateStatsForAllUpstreams();
+                        if (mStatsProvider != null) mStatsProvider.pushTetherStats();
+                    }
+
+                    @Override
+                    public void onSupportAvailable() {
+                        if (!started()) return;
+                        mLog.log("onSupportAvailable");
+
+                        // [1] Poll for statistics and trigger a sweep of stats
+                        // by observers. We need to do this to ensure that any
+                        // limits set take into account any software tethering
+                        // traffic that has been happening in the meantime.
+                        updateStatsForAllUpstreams();
+                        if (mStatsProvider != null) mStatsProvider.pushTetherStats();
+                        // [2] (Re)Push all state.
+                        computeAndPushLocalPrefixes(UpdateType.FORCE);
+                        pushAllDownstreamState();
+                        pushUpstreamParameters(null);
+                    }
+
+                    @Override
+                    public void onStoppedLimitReached() {
+                        if (!started()) return;
+                        mLog.log("onStoppedLimitReached");
+
+                        // We cannot reliably determine on which interface the limit was reached,
+                        // because the HAL interface does not specify it. We cannot just use the
+                        // current upstream, because that might have changed since the time that
+                        // the HAL queued the callback.
+                        // TODO: rev the HAL so that it provides an interface name.
+
+                        updateStatsForCurrentUpstream();
+                        if (mStatsProvider != null) {
+                            mStatsProvider.pushTetherStats();
+                            // Push stats to service does not cause the service react to it
+                            // immediately. Inform the service about limit reached.
+                            mStatsProvider.notifyLimitReached();
+                        }
+                    }
+
+                    @Override
+                    public void onNatTimeoutUpdate(int proto,
+                                                   String srcAddr, int srcPort,
+                                                   String dstAddr, int dstPort) {
+                        if (!started()) return;
+                        updateNatTimeout(proto, srcAddr, srcPort, dstAddr, dstPort);
+                    }
+                });
+
+        final boolean isStarted = started();
+        if (!isStarted) {
+            mLog.i("tethering offload control not supported");
+            stop();
+        } else {
+            mLog.log("tethering offload started");
+            mNatUpdateCallbacksReceived = 0;
+            mNatUpdateNetlinkErrors = 0;
+            maybeSchedulePollingStats();
+        }
+        return isStarted;
+    }
+
+    /** Stop hardware offload. */
+    public void stop() {
+        // Completely stops tethering offload. After this method is called, it is no longer safe to
+        // call any HAL method, no callbacks from the hardware will be delivered, and any in-flight
+        // callbacks must be ignored. Offload may be started again by calling start().
+        final boolean wasStarted = started();
+        updateStatsForCurrentUpstream();
+        mUpstreamLinkProperties = null;
+        mHwInterface.stopOffloadControl();
+        mControlInitialized = false;
+        mConfigInitialized = false;
+        if (mHandler.hasCallbacks(mScheduledPollingTask)) {
+            mHandler.removeCallbacks(mScheduledPollingTask);
+        }
+        if (wasStarted) mLog.log("tethering offload stopped");
+    }
+
+    private boolean started() {
+        return mConfigInitialized && mControlInitialized;
+    }
+
+    @VisibleForTesting
+    class OffloadTetheringStatsProvider extends NetworkStatsProvider {
+        // These stats must only ever be touched on the handler thread.
+        @NonNull
+        private NetworkStats mIfaceStats = new NetworkStats(0L, 0);
+        @NonNull
+        private NetworkStats mUidStats = new NetworkStats(0L, 0);
+
+        /**
+         * A helper function that collect tether stats from local hashmap. Note that this does not
+         * invoke binder call.
+         */
+        @VisibleForTesting
+        @NonNull
+        NetworkStats getTetherStats(@NonNull StatsType how) {
+            NetworkStats stats = new NetworkStats(0L, 0);
+            final int uid = (how == StatsType.STATS_PER_UID) ? UID_TETHERING : UID_ALL;
+
+            for (final Map.Entry<String, ForwardedStats> kv : mForwardedStats.entrySet()) {
+                final ForwardedStats value = kv.getValue();
+                final Entry entry = new Entry(kv.getKey(), uid, SET_DEFAULT, TAG_NONE, METERED_NO,
+                        ROAMING_NO, DEFAULT_NETWORK_NO, value.rxBytes, 0L, value.txBytes, 0L, 0L);
+                stats = stats.addEntry(entry);
+            }
+
+            return stats;
+        }
+
+        @Override
+        public void onSetLimit(String iface, long quotaBytes) {
+            // Listen for all iface is necessary since upstream might be changed after limit
+            // is set.
+            mHandler.post(() -> {
+                final Long curIfaceQuota = mInterfaceQuotas.get(iface);
+
+                // If the quota is set to unlimited, the value set to HAL is Long.MAX_VALUE,
+                // which is ~8.4 x 10^6 TiB, no one can actually reach it. Thus, it is not
+                // useful to set it multiple times.
+                // Otherwise, the quota needs to be updated to tell HAL to re-count from now even
+                // if the quota is the same as the existing one.
+                if (null == curIfaceQuota && QUOTA_UNLIMITED == quotaBytes) return;
+
+                if (quotaBytes == QUOTA_UNLIMITED) {
+                    mInterfaceQuotas.remove(iface);
+                } else {
+                    mInterfaceQuotas.put(iface, quotaBytes);
+                }
+                maybeUpdateDataLimit(iface);
+            });
+        }
+
+        /**
+         * Push stats to service, but does not cause a force polling. Note that this can only be
+         * called on the handler thread.
+         */
+        public void pushTetherStats() {
+            // TODO: remove the accumulated stats and report the diff from HAL directly.
+            final NetworkStats ifaceDiff =
+                    getTetherStats(StatsType.STATS_PER_IFACE).subtract(mIfaceStats);
+            final NetworkStats uidDiff =
+                    getTetherStats(StatsType.STATS_PER_UID).subtract(mUidStats);
+            try {
+                notifyStatsUpdated(0 /* token */, ifaceDiff, uidDiff);
+                mIfaceStats = mIfaceStats.add(ifaceDiff);
+                mUidStats = mUidStats.add(uidDiff);
+            } catch (RuntimeException e) {
+                mLog.e("Cannot report network stats: ", e);
+            }
+        }
+
+        @Override
+        public void onRequestStatsUpdate(int token) {
+            // Do not attempt to update stats by querying the offload HAL
+            // synchronously from a different thread than the Handler thread. http://b/64771555.
+            mHandler.post(() -> {
+                updateStatsForCurrentUpstream();
+                pushTetherStats();
+            });
+        }
+
+        @Override
+        public void onSetAlert(long quotaBytes) {
+            // TODO: Ask offload HAL to notify alert without stopping traffic.
+            // Post it to handler thread since it access remaining quota bytes.
+            mHandler.post(() -> {
+                updateAlertQuota(quotaBytes);
+                maybeSchedulePollingStats();
+            });
+        }
+    }
+
+    private String currentUpstreamInterface() {
+        return (mUpstreamLinkProperties != null)
+                ? mUpstreamLinkProperties.getInterfaceName() : null;
+    }
+
+    private void maybeUpdateStats(String iface) {
+        if (TextUtils.isEmpty(iface)) {
+            return;
+        }
+
+        // Always called on the handler thread.
+        //
+        // Use get()/put() instead of updating ForwardedStats in place because we can be called
+        // concurrently with getTetherStats. In combination with the guarantees provided by
+        // ConcurrentHashMap, this ensures that getTetherStats always gets the most recent copy of
+        // the stats for each interface, and does not observe partial writes where rxBytes is
+        // updated and txBytes is not.
+        ForwardedStats diff = mHwInterface.getForwardedStats(iface);
+        final long usedAlertQuota = diff.rxBytes + diff.txBytes;
+        ForwardedStats base = mForwardedStats.get(iface);
+        if (base != null) {
+            diff.add(base);
+        }
+
+        // Update remaining alert quota if it is still positive.
+        if (mRemainingAlertQuota > 0 && usedAlertQuota > 0) {
+            // Trim to zero if overshoot.
+            final long newQuota = Math.max(mRemainingAlertQuota - usedAlertQuota, 0);
+            updateAlertQuota(newQuota);
+        }
+
+        mForwardedStats.put(iface, diff);
+        // diff is a new object, just created by getForwardedStats(). Therefore, anyone reading from
+        // mForwardedStats (i.e., any caller of getTetherStats) will see the new stats immediately.
+    }
+
+    /**
+     * Update remaining alert quota, fire the {@link NetworkStatsProvider#notifyAlertReached()}
+     * callback when it reaches zero. This can be invoked either from service setting the alert, or
+     * {@code maybeUpdateStats} when updating stats. Note that this can be only called on
+     * handler thread.
+     *
+     * @param newQuota non-negative value to indicate the new quota, or
+     *                 {@link NetworkStatsProvider#QUOTA_UNLIMITED} to indicate there is no
+     *                 quota.
+     */
+    private void updateAlertQuota(long newQuota) {
+        if (newQuota < QUOTA_UNLIMITED) {
+            throw new IllegalArgumentException("invalid quota value " + newQuota);
+        }
+        if (mRemainingAlertQuota == newQuota) return;
+
+        mRemainingAlertQuota = newQuota;
+        if (mRemainingAlertQuota == 0) {
+            mLog.i("notifyAlertReached");
+            if (mStatsProvider != null) mStatsProvider.notifyAlertReached();
+        }
+    }
+
+    /**
+     * Schedule polling if needed, this will be stopped if offload has been
+     * stopped or remaining quota reaches zero or upstream is empty.
+     * Note that this can be only called on handler thread.
+     */
+    private void maybeSchedulePollingStats() {
+        if (!isPollingStatsNeeded()) return;
+
+        if (mHandler.hasCallbacks(mScheduledPollingTask)) {
+            mHandler.removeCallbacks(mScheduledPollingTask);
+        }
+        mHandler.postDelayed(mScheduledPollingTask,
+                mDeps.getTetherConfig().getOffloadPollInterval());
+    }
+
+    private boolean isPollingStatsNeeded() {
+        return started() && mRemainingAlertQuota > 0
+                && !TextUtils.isEmpty(currentUpstreamInterface())
+                && mDeps.getTetherConfig() != null
+                && mDeps.getTetherConfig().getOffloadPollInterval()
+                >= DEFAULT_TETHER_OFFLOAD_POLL_INTERVAL_MS;
+    }
+
+    private boolean maybeUpdateDataLimit(String iface) {
+        // setDataLimit may only be called while offload is occurring on this upstream.
+        if (!started() || !TextUtils.equals(iface, currentUpstreamInterface())) {
+            return true;
+        }
+
+        Long limit = mInterfaceQuotas.get(iface);
+        if (limit == null) {
+            limit = Long.MAX_VALUE;
+        }
+
+        return mHwInterface.setDataLimit(iface, limit);
+    }
+
+    private void updateStatsForCurrentUpstream() {
+        maybeUpdateStats(currentUpstreamInterface());
+    }
+
+    private void updateStatsForAllUpstreams() {
+        // In practice, there should only ever be a single digit number of
+        // upstream interfaces over the lifetime of an active tethering session.
+        // Roughly speaking, imagine a very ambitious one or two of each of the
+        // following interface types: [ "rmnet_data", "wlan", "eth", "rndis" ].
+        for (Map.Entry<String, ForwardedStats> kv : mForwardedStats.entrySet()) {
+            maybeUpdateStats(kv.getKey());
+        }
+    }
+
+    /** Set current tethering upstream LinkProperties. */
+    public void setUpstreamLinkProperties(LinkProperties lp) {
+        if (!started() || Objects.equals(mUpstreamLinkProperties, lp)) return;
+
+        final String prevUpstream = currentUpstreamInterface();
+
+        mUpstreamLinkProperties = (lp != null) ? new LinkProperties(lp) : null;
+        // Make sure we record this interface in the ForwardedStats map.
+        final String iface = currentUpstreamInterface();
+        if (!TextUtils.isEmpty(iface)) mForwardedStats.putIfAbsent(iface, EMPTY_STATS);
+
+        maybeSchedulePollingStats();
+
+        // TODO: examine return code and decide what to do if programming
+        // upstream parameters fails (probably just wait for a subsequent
+        // onOffloadEvent() callback to tell us offload is available again and
+        // then reapply all state).
+        computeAndPushLocalPrefixes(UpdateType.IF_NEEDED);
+        pushUpstreamParameters(prevUpstream);
+    }
+
+    /** Set local prefixes. */
+    public void setLocalPrefixes(Set<IpPrefix> localPrefixes) {
+        mExemptPrefixes = localPrefixes;
+
+        if (!started()) return;
+        computeAndPushLocalPrefixes(UpdateType.IF_NEEDED);
+    }
+
+    /** Update current downstream LinkProperties. */
+    public void notifyDownstreamLinkProperties(LinkProperties lp) {
+        final String ifname = lp.getInterfaceName();
+        final LinkProperties oldLp = mDownstreams.put(ifname, new LinkProperties(lp));
+        if (Objects.equals(oldLp, lp)) return;
+
+        if (!started()) return;
+        pushDownstreamState(oldLp, lp);
+    }
+
+    private void pushDownstreamState(LinkProperties oldLp, LinkProperties newLp) {
+        final String ifname = newLp.getInterfaceName();
+        final List<RouteInfo> oldRoutes =
+                (oldLp != null) ? oldLp.getRoutes() : Collections.EMPTY_LIST;
+        final List<RouteInfo> newRoutes = newLp.getRoutes();
+
+        // For each old route, if not in new routes: remove.
+        for (RouteInfo ri : oldRoutes) {
+            if (shouldIgnoreDownstreamRoute(ri)) continue;
+            if (!newRoutes.contains(ri)) {
+                mHwInterface.removeDownstreamPrefix(ifname, ri.getDestination().toString());
+            }
+        }
+
+        // For each new route, if not in old routes: add.
+        for (RouteInfo ri : newRoutes) {
+            if (shouldIgnoreDownstreamRoute(ri)) continue;
+            if (!oldRoutes.contains(ri)) {
+                mHwInterface.addDownstreamPrefix(ifname, ri.getDestination().toString());
+            }
+        }
+    }
+
+    private void pushAllDownstreamState() {
+        for (LinkProperties lp : mDownstreams.values()) {
+            pushDownstreamState(null, lp);
+        }
+    }
+
+    /** Remove downstream interface from offload hardware. */
+    public void removeDownstreamInterface(String ifname) {
+        final LinkProperties lp = mDownstreams.remove(ifname);
+        if (lp == null) return;
+
+        if (!started()) return;
+
+        for (RouteInfo route : lp.getRoutes()) {
+            if (shouldIgnoreDownstreamRoute(route)) continue;
+            mHwInterface.removeDownstreamPrefix(ifname, route.getDestination().toString());
+        }
+    }
+
+    private boolean isOffloadDisabled() {
+        final int defaultDisposition = mHwInterface.getDefaultTetherOffloadDisabled();
+        return (Settings.Global.getInt(
+                mContentResolver, TETHER_OFFLOAD_DISABLED, defaultDisposition) != 0);
+    }
+
+    private boolean pushUpstreamParameters(String prevUpstream) {
+        final String iface = currentUpstreamInterface();
+
+        if (TextUtils.isEmpty(iface)) {
+            final boolean rval = mHwInterface.setUpstreamParameters("", ANYIP, ANYIP, null);
+            // Update stats after we've told the hardware to stop forwarding so
+            // we don't miss packets.
+            maybeUpdateStats(prevUpstream);
+            return rval;
+        }
+
+        // A stacked interface cannot be an upstream for hardware offload.
+        // Consequently, we examine only the primary interface name, look at
+        // getAddresses() rather than getAllAddresses(), and check getRoutes()
+        // rather than getAllRoutes().
+        final ArrayList<String> v6gateways = new ArrayList<>();
+        String v4addr = null;
+        String v4gateway = null;
+
+        for (InetAddress ip : mUpstreamLinkProperties.getAddresses()) {
+            if (ip instanceof Inet4Address) {
+                v4addr = ip.getHostAddress();
+                break;
+            }
+        }
+
+        // Find the gateway addresses of all default routes of either address family.
+        for (RouteInfo ri : mUpstreamLinkProperties.getRoutes()) {
+            if (!ri.hasGateway()) continue;
+
+            final String gateway = ri.getGateway().getHostAddress();
+            final InetAddress address = ri.getDestination().getAddress();
+            if (ri.isDefaultRoute() && address instanceof Inet4Address) {
+                v4gateway = gateway;
+            } else if (ri.isDefaultRoute() && address instanceof Inet6Address) {
+                v6gateways.add(gateway);
+            }
+        }
+
+        boolean success = mHwInterface.setUpstreamParameters(
+                iface, v4addr, v4gateway, (v6gateways.isEmpty() ? null : v6gateways));
+
+        if (!success) {
+            return success;
+        }
+
+        // Update stats after we've told the hardware to change routing so we don't miss packets.
+        maybeUpdateStats(prevUpstream);
+
+        // Data limits can only be set once offload is running on the upstream.
+        success = maybeUpdateDataLimit(iface);
+        if (!success) {
+            // If we failed to set a data limit, don't use this upstream, because we don't want to
+            // blow through the data limit that we were told to apply.
+            mLog.log("Setting data limit for " + iface + " failed, disabling offload.");
+            stop();
+        }
+
+        return success;
+    }
+
+    private boolean computeAndPushLocalPrefixes(UpdateType how) {
+        final boolean force = (how == UpdateType.FORCE);
+        final Set<String> localPrefixStrs = computeLocalPrefixStrings(
+                mExemptPrefixes, mUpstreamLinkProperties);
+        if (!force && mLastLocalPrefixStrs.equals(localPrefixStrs)) return true;
+
+        mLastLocalPrefixStrs = localPrefixStrs;
+        return mHwInterface.setLocalPrefixes(new ArrayList<>(localPrefixStrs));
+    }
+
+    // TODO: Factor in downstream LinkProperties once that information is available.
+    private static Set<String> computeLocalPrefixStrings(
+            Set<IpPrefix> localPrefixes, LinkProperties upstreamLinkProperties) {
+        // Create an editable copy.
+        final Set<IpPrefix> prefixSet = new HashSet<>(localPrefixes);
+
+        // TODO: If a downstream interface (not currently passed in) is reusing
+        // the /64 of the upstream (64share) then:
+        //
+        //     [a] remove that /64 from the local prefixes
+        //     [b] add in /128s for IP addresses on the downstream interface
+        //     [c] add in /128s for IP addresses on the upstream interface
+        //
+        // Until downstream information is available here, simply add /128s from
+        // the upstream network; they'll just be redundant with their /64.
+        if (upstreamLinkProperties != null) {
+            for (LinkAddress linkAddr : upstreamLinkProperties.getLinkAddresses()) {
+                if (!linkAddr.isGlobalPreferred()) continue;
+                final InetAddress ip = linkAddr.getAddress();
+                if (!(ip instanceof Inet6Address)) continue;
+                prefixSet.add(new IpPrefix(ip, 128));
+            }
+        }
+
+        final HashSet<String> localPrefixStrs = new HashSet<>();
+        for (IpPrefix pfx : prefixSet) localPrefixStrs.add(pfx.toString());
+        return localPrefixStrs;
+    }
+
+    private static boolean shouldIgnoreDownstreamRoute(RouteInfo route) {
+        // Ignore any link-local routes.
+        final IpPrefix destination = route.getDestination();
+        final LinkAddress linkAddr = new LinkAddress(destination.getAddress(),
+                destination.getPrefixLength());
+        if (!linkAddr.isGlobalPreferred()) return true;
+
+        return false;
+    }
+
+    /** Dump information. */
+    public void dump(IndentingPrintWriter pw) {
+        if (isOffloadDisabled()) {
+            pw.println("Offload disabled");
+            return;
+        }
+        final boolean isStarted = started();
+        pw.println("Offload HALs " + (isStarted ? "started" : "not started"));
+        LinkProperties lp = mUpstreamLinkProperties;
+        String upstream = (lp != null) ? lp.getInterfaceName() : null;
+        pw.println("Current upstream: " + upstream);
+        pw.println("Exempt prefixes: " + mLastLocalPrefixStrs);
+        pw.println("NAT timeout update callbacks received during the "
+                + (isStarted ? "current" : "last")
+                + " offload session: "
+                + mNatUpdateCallbacksReceived);
+        pw.println("NAT timeout update netlink errors during the "
+                + (isStarted ? "current" : "last")
+                + " offload session: "
+                + mNatUpdateNetlinkErrors);
+    }
+
+    private void updateNatTimeout(
+            int proto, String srcAddr, int srcPort, String dstAddr, int dstPort) {
+        final String protoName = protoNameFor(proto);
+        if (protoName == null) {
+            mLog.e("Unknown NAT update callback protocol: " + proto);
+            return;
+        }
+
+        final Inet4Address src = parseIPv4Address(srcAddr);
+        if (src == null) {
+            mLog.e("Failed to parse IPv4 address: " + srcAddr);
+            return;
+        }
+
+        if (!isValidUdpOrTcpPort(srcPort)) {
+            mLog.e("Invalid src port: " + srcPort);
+            return;
+        }
+
+        final Inet4Address dst = parseIPv4Address(dstAddr);
+        if (dst == null) {
+            mLog.e("Failed to parse IPv4 address: " + dstAddr);
+            return;
+        }
+
+        if (!isValidUdpOrTcpPort(dstPort)) {
+            mLog.e("Invalid dst port: " + dstPort);
+            return;
+        }
+
+        mNatUpdateCallbacksReceived++;
+        final String natDescription = String.format("%s (%s, %s) -> (%s, %s)",
+                protoName, srcAddr, srcPort, dstAddr, dstPort);
+        if (DBG) {
+            mLog.log("NAT timeout update: " + natDescription);
+        }
+
+        final int timeoutSec = connectionTimeoutUpdateSecondsFor(proto);
+        final byte[] msg = ConntrackMessage.newIPv4TimeoutUpdateRequest(
+                proto, src, srcPort, dst, dstPort, timeoutSec);
+
+        try {
+            NetlinkSocket.sendOneShotKernelMessage(OsConstants.NETLINK_NETFILTER, msg);
+        } catch (ErrnoException e) {
+            mNatUpdateNetlinkErrors++;
+            mLog.e("Error updating NAT conntrack entry >" + natDescription + "<: " + e
+                    + ", msg: " + NetlinkConstants.hexify(msg));
+            mLog.log("NAT timeout update callbacks received: " + mNatUpdateCallbacksReceived);
+            mLog.log("NAT timeout update netlink errors: " + mNatUpdateNetlinkErrors);
+        }
+    }
+
+    private static Inet4Address parseIPv4Address(String addrString) {
+        try {
+            final InetAddress ip = InetAddresses.parseNumericAddress(addrString);
+            // TODO: Consider other sanitization steps here, including perhaps:
+            //           not eql to 0.0.0.0
+            //           not within 169.254.0.0/16
+            //           not within ::ffff:0.0.0.0/96
+            //           not within ::/96
+            // et cetera.
+            if (ip instanceof Inet4Address) {
+                return (Inet4Address) ip;
+            }
+        } catch (IllegalArgumentException iae) { }
+        return null;
+    }
+
+    private static String protoNameFor(int proto) {
+        // OsConstants values are not constant expressions; no switch statement.
+        if (proto == OsConstants.IPPROTO_UDP) {
+            return "UDP";
+        } else if (proto == OsConstants.IPPROTO_TCP) {
+            return "TCP";
+        }
+        return null;
+    }
+
+    private static int connectionTimeoutUpdateSecondsFor(int proto) {
+        // TODO: Replace this with more thoughtful work, perhaps reading from
+        // and maybe writing to any required
+        //
+        //     /proc/sys/net/netfilter/nf_conntrack_tcp_timeout_*
+        //     /proc/sys/net/netfilter/nf_conntrack_udp_timeout{,_stream}
+        //
+        // entries.  TBD.
+        if (proto == OsConstants.IPPROTO_TCP) {
+            // Cf. /proc/sys/net/netfilter/nf_conntrack_tcp_timeout_established
+            return 432000;
+        } else {
+            // Cf. /proc/sys/net/netfilter/nf_conntrack_udp_timeout_stream
+            return 180;
+        }
+    }
+
+    private static boolean isValidUdpOrTcpPort(int port) {
+        return port > 0 && port < 65536;
+    }
+}
diff --git a/Tethering/src/com/android/networkstack/tethering/OffloadHardwareInterface.java b/Tethering/src/com/android/networkstack/tethering/OffloadHardwareInterface.java
new file mode 100644
index 0000000..da5f25b
--- /dev/null
+++ b/Tethering/src/com/android/networkstack/tethering/OffloadHardwareInterface.java
@@ -0,0 +1,574 @@
+/*
+ * Copyright (C) 2017 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.android.networkstack.tethering;
+
+import static android.net.netlink.StructNlMsgHdr.NLM_F_DUMP;
+import static android.net.netlink.StructNlMsgHdr.NLM_F_REQUEST;
+import static android.net.util.TetheringUtils.uint16;
+
+import android.annotation.NonNull;
+import android.hardware.tetheroffload.config.V1_0.IOffloadConfig;
+import android.hardware.tetheroffload.control.V1_0.IOffloadControl;
+import android.hardware.tetheroffload.control.V1_0.ITetheringOffloadCallback;
+import android.hardware.tetheroffload.control.V1_0.NatTimeoutUpdate;
+import android.hardware.tetheroffload.control.V1_0.NetworkProtocol;
+import android.hardware.tetheroffload.control.V1_0.OffloadCallbackEvent;
+import android.net.netlink.NetlinkSocket;
+import android.net.netlink.StructNfGenMsg;
+import android.net.netlink.StructNlMsgHdr;
+import android.net.util.SharedLog;
+import android.net.util.SocketUtils;
+import android.os.Handler;
+import android.os.NativeHandle;
+import android.os.RemoteException;
+import android.system.ErrnoException;
+import android.system.Os;
+import android.system.OsConstants;
+
+import com.android.internal.annotations.VisibleForTesting;
+
+import java.io.FileDescriptor;
+import java.io.IOException;
+import java.io.InterruptedIOException;
+import java.net.SocketAddress;
+import java.net.SocketException;
+import java.nio.ByteBuffer;
+import java.nio.ByteOrder;
+import java.util.ArrayList;
+import java.util.NoSuchElementException;
+
+
+/**
+ * Capture tethering dependencies, for injection.
+ *
+ * @hide
+ */
+public class OffloadHardwareInterface {
+    private static final String TAG = OffloadHardwareInterface.class.getSimpleName();
+    private static final String YIELDS = " -> ";
+    // Change this value to control whether tether offload is enabled or
+    // disabled by default in the absence of an explicit Settings value.
+    // See accompanying unittest to distinguish 0 from non-0 values.
+    private static final int DEFAULT_TETHER_OFFLOAD_DISABLED = 0;
+    private static final String NO_INTERFACE_NAME = "";
+    private static final String NO_IPV4_ADDRESS = "";
+    private static final String NO_IPV4_GATEWAY = "";
+    // Reference kernel/uapi/linux/netfilter/nfnetlink_compat.h
+    public static final int NF_NETLINK_CONNTRACK_NEW = 1;
+    public static final int NF_NETLINK_CONNTRACK_UPDATE = 2;
+    public static final int NF_NETLINK_CONNTRACK_DESTROY = 4;
+    // Reference libnetfilter_conntrack/linux_nfnetlink_conntrack.h
+    public static final short NFNL_SUBSYS_CTNETLINK = 1;
+    public static final short IPCTNL_MSG_CT_NEW = 0;
+    public static final short IPCTNL_MSG_CT_GET = 1;
+
+    private final long NETLINK_MESSAGE_TIMEOUT_MS = 500;
+
+    private final Handler mHandler;
+    private final SharedLog mLog;
+    private final Dependencies mDeps;
+    private IOffloadControl mOffloadControl;
+    private TetheringOffloadCallback mTetheringOffloadCallback;
+    private ControlCallback mControlCallback;
+
+    /** The callback to notify status of offload management process. */
+    public static class ControlCallback {
+        /** Offload started. */
+        public void onStarted() {}
+        /**
+         * Offload stopped because an error has occurred in lower layer.
+         */
+        public void onStoppedError() {}
+        /**
+         * Offload stopped because the device has moved to a bearer on which hardware offload is
+         * not supported. Subsequent calls to setUpstreamParameters and add/removeDownstream will
+         * likely fail and cannot be presumed to be saved inside of the hardware management process.
+         * Upon receiving #onSupportAvailable(), the caller should reprogram the hardware to begin
+         * offload again.
+         */
+        public void onStoppedUnsupported() {}
+        /** Indicate that offload is able to proivde support for this time. */
+        public void onSupportAvailable() {}
+        /** Offload stopped because of usage limit reached. */
+        public void onStoppedLimitReached() {}
+
+        /** Indicate to update NAT timeout. */
+        public void onNatTimeoutUpdate(int proto,
+                                       String srcAddr, int srcPort,
+                                       String dstAddr, int dstPort) {}
+    }
+
+    /** The object which records Tx/Rx forwarded bytes. */
+    public static class ForwardedStats {
+        public long rxBytes;
+        public long txBytes;
+
+        public ForwardedStats() {
+            rxBytes = 0;
+            txBytes = 0;
+        }
+
+        @VisibleForTesting
+        public ForwardedStats(long rxBytes, long txBytes) {
+            this.rxBytes = rxBytes;
+            this.txBytes = txBytes;
+        }
+
+        /** Add Tx/Rx bytes. */
+        public void add(ForwardedStats other) {
+            rxBytes += other.rxBytes;
+            txBytes += other.txBytes;
+        }
+
+        /** Returns the string representation of this object. */
+        public String toString() {
+            return String.format("rx:%s tx:%s", rxBytes, txBytes);
+        }
+    }
+
+    public OffloadHardwareInterface(Handler h, SharedLog log) {
+        this(h, log, new Dependencies(log));
+    }
+
+    OffloadHardwareInterface(Handler h, SharedLog log, Dependencies deps) {
+        mHandler = h;
+        mLog = log.forSubComponent(TAG);
+        mDeps = deps;
+    }
+
+    /** Capture OffloadHardwareInterface dependencies, for injection. */
+    static class Dependencies {
+        private final SharedLog mLog;
+
+        Dependencies(SharedLog log) {
+            mLog = log;
+        }
+
+        public IOffloadConfig getOffloadConfig() {
+            try {
+                return IOffloadConfig.getService(true /*retry*/);
+            } catch (RemoteException | NoSuchElementException e) {
+                mLog.e("getIOffloadConfig error " + e);
+                return null;
+            }
+        }
+
+        public IOffloadControl getOffloadControl() {
+            try {
+                return IOffloadControl.getService(true /*retry*/);
+            } catch (RemoteException | NoSuchElementException e) {
+                mLog.e("tethering offload control not supported: " + e);
+                return null;
+            }
+        }
+
+        public NativeHandle createConntrackSocket(final int groups) {
+            final FileDescriptor fd;
+            try {
+                fd = NetlinkSocket.forProto(OsConstants.NETLINK_NETFILTER);
+            } catch (ErrnoException e) {
+                mLog.e("Unable to create conntrack socket " + e);
+                return null;
+            }
+
+            final SocketAddress sockAddr = SocketUtils.makeNetlinkSocketAddress(0, groups);
+            try {
+                Os.bind(fd, sockAddr);
+            } catch (ErrnoException | SocketException e) {
+                mLog.e("Unable to bind conntrack socket for groups " + groups + " error: " + e);
+                try {
+                    SocketUtils.closeSocket(fd);
+                } catch (IOException ie) {
+                    // Nothing we can do here
+                }
+                return null;
+            }
+            try {
+                Os.connect(fd, sockAddr);
+            } catch (ErrnoException | SocketException e) {
+                mLog.e("connect to kernel fail for groups " + groups + " error: " + e);
+                try {
+                    SocketUtils.closeSocket(fd);
+                } catch (IOException ie) {
+                    // Nothing we can do here
+                }
+                return null;
+            }
+
+            return new NativeHandle(fd, true);
+        }
+    }
+
+    /** Get default value indicating whether offload is supported. */
+    public int getDefaultTetherOffloadDisabled() {
+        return DEFAULT_TETHER_OFFLOAD_DISABLED;
+    }
+
+    /**
+     * Offload management process need to know conntrack rules to support NAT, but it may not have
+     * permission to create netlink netfilter sockets. Create two netlink netfilter sockets and
+     * share them with offload management process.
+     */
+    public boolean initOffloadConfig() {
+        final IOffloadConfig offloadConfig = mDeps.getOffloadConfig();
+        if (offloadConfig == null) {
+            mLog.e("Could not find IOffloadConfig service");
+            return false;
+        }
+        // Per the IConfigOffload definition:
+        //
+        // h1    provides a file descriptor bound to the following netlink groups
+        //       (NF_NETLINK_CONNTRACK_NEW | NF_NETLINK_CONNTRACK_DESTROY).
+        //
+        // h2    provides a file descriptor bound to the following netlink groups
+        //       (NF_NETLINK_CONNTRACK_UPDATE | NF_NETLINK_CONNTRACK_DESTROY).
+        final NativeHandle h1 = mDeps.createConntrackSocket(
+                NF_NETLINK_CONNTRACK_NEW | NF_NETLINK_CONNTRACK_DESTROY);
+        if (h1 == null) return false;
+
+        sendIpv4NfGenMsg(h1, (short) ((NFNL_SUBSYS_CTNETLINK << 8) | IPCTNL_MSG_CT_GET),
+                           (short) (NLM_F_REQUEST | NLM_F_DUMP));
+
+        final NativeHandle h2 = mDeps.createConntrackSocket(
+                NF_NETLINK_CONNTRACK_UPDATE | NF_NETLINK_CONNTRACK_DESTROY);
+        if (h2 == null) {
+            closeFdInNativeHandle(h1);
+            return false;
+        }
+
+        final CbResults results = new CbResults();
+        try {
+            offloadConfig.setHandles(h1, h2,
+                    (boolean success, String errMsg) -> {
+                        results.mSuccess = success;
+                        results.mErrMsg = errMsg;
+                    });
+        } catch (RemoteException e) {
+            record("initOffloadConfig, setHandles fail", e);
+            return false;
+        }
+        // Explicitly close FDs.
+        closeFdInNativeHandle(h1);
+        closeFdInNativeHandle(h2);
+
+        record("initOffloadConfig, setHandles results:", results);
+        return results.mSuccess;
+    }
+
+    @VisibleForTesting
+    public void sendIpv4NfGenMsg(@NonNull NativeHandle handle, short type, short flags) {
+        final int length = StructNlMsgHdr.STRUCT_SIZE + StructNfGenMsg.STRUCT_SIZE;
+        final byte[] msg = new byte[length];
+        final ByteBuffer byteBuffer = ByteBuffer.wrap(msg);
+        byteBuffer.order(ByteOrder.nativeOrder());
+
+        final StructNlMsgHdr nlh = new StructNlMsgHdr();
+        nlh.nlmsg_len = length;
+        nlh.nlmsg_type = type;
+        nlh.nlmsg_flags = flags;
+        nlh.nlmsg_seq = 0;
+        nlh.pack(byteBuffer);
+
+        // Header needs to be added to buffer since a generic netlink request is being sent.
+        final StructNfGenMsg nfh = new StructNfGenMsg((byte) OsConstants.AF_INET);
+        nfh.pack(byteBuffer);
+
+        try {
+            NetlinkSocket.sendMessage(handle.getFileDescriptor(), msg, 0 /* offset */, length,
+                                      NETLINK_MESSAGE_TIMEOUT_MS);
+        } catch (ErrnoException | InterruptedIOException e) {
+            mLog.e("Unable to send netfilter message, error: " + e);
+        }
+    }
+
+    private void closeFdInNativeHandle(final NativeHandle h) {
+        try {
+            h.close();
+        } catch (IOException | IllegalStateException e) {
+            // IllegalStateException means fd is already closed, do nothing here.
+            // Also nothing we can do if IOException.
+        }
+    }
+
+    /** Initialize the tethering offload HAL. */
+    public boolean initOffloadControl(ControlCallback controlCb) {
+        mControlCallback = controlCb;
+
+        if (mOffloadControl == null) {
+            mOffloadControl = mDeps.getOffloadControl();
+            if (mOffloadControl == null) {
+                mLog.e("tethering IOffloadControl.getService() returned null");
+                return false;
+            }
+        }
+
+        final String logmsg = String.format("initOffloadControl(%s)",
+                (controlCb == null) ? "null"
+                        : "0x" + Integer.toHexString(System.identityHashCode(controlCb)));
+
+        mTetheringOffloadCallback = new TetheringOffloadCallback(mHandler, mControlCallback, mLog);
+        final CbResults results = new CbResults();
+        try {
+            mOffloadControl.initOffload(
+                    mTetheringOffloadCallback,
+                    (boolean success, String errMsg) -> {
+                        results.mSuccess = success;
+                        results.mErrMsg = errMsg;
+                    });
+        } catch (RemoteException e) {
+            record(logmsg, e);
+            return false;
+        }
+
+        record(logmsg, results);
+        return results.mSuccess;
+    }
+
+    /** Stop IOffloadControl. */
+    public void stopOffloadControl() {
+        if (mOffloadControl != null) {
+            try {
+                mOffloadControl.stopOffload(
+                        (boolean success, String errMsg) -> {
+                            if (!success) mLog.e("stopOffload failed: " + errMsg);
+                        });
+            } catch (RemoteException e) {
+                mLog.e("failed to stopOffload: " + e);
+            }
+        }
+        mOffloadControl = null;
+        mTetheringOffloadCallback = null;
+        mControlCallback = null;
+        mLog.log("stopOffloadControl()");
+    }
+
+    /** Get Tx/Rx usage from last query. */
+    public ForwardedStats getForwardedStats(String upstream) {
+        final String logmsg = String.format("getForwardedStats(%s)",  upstream);
+
+        final ForwardedStats stats = new ForwardedStats();
+        try {
+            mOffloadControl.getForwardedStats(
+                    upstream,
+                    (long rxBytes, long txBytes) -> {
+                        stats.rxBytes = (rxBytes > 0) ? rxBytes : 0;
+                        stats.txBytes = (txBytes > 0) ? txBytes : 0;
+                    });
+        } catch (RemoteException e) {
+            record(logmsg, e);
+            return stats;
+        }
+
+        return stats;
+    }
+
+    /** Set local prefixes to offload management process. */
+    public boolean setLocalPrefixes(ArrayList<String> localPrefixes) {
+        final String logmsg = String.format("setLocalPrefixes([%s])",
+                String.join(",", localPrefixes));
+
+        final CbResults results = new CbResults();
+        try {
+            mOffloadControl.setLocalPrefixes(localPrefixes,
+                    (boolean success, String errMsg) -> {
+                        results.mSuccess = success;
+                        results.mErrMsg = errMsg;
+                    });
+        } catch (RemoteException e) {
+            record(logmsg, e);
+            return false;
+        }
+
+        record(logmsg, results);
+        return results.mSuccess;
+    }
+
+    /** Set data limit value to offload management process. */
+    public boolean setDataLimit(String iface, long limit) {
+
+        final String logmsg = String.format("setDataLimit(%s, %d)", iface, limit);
+
+        final CbResults results = new CbResults();
+        try {
+            mOffloadControl.setDataLimit(
+                    iface, limit,
+                    (boolean success, String errMsg) -> {
+                        results.mSuccess = success;
+                        results.mErrMsg = errMsg;
+                    });
+        } catch (RemoteException e) {
+            record(logmsg, e);
+            return false;
+        }
+
+        record(logmsg, results);
+        return results.mSuccess;
+    }
+
+    /** Set upstream parameters to offload management process. */
+    public boolean setUpstreamParameters(
+            String iface, String v4addr, String v4gateway, ArrayList<String> v6gws) {
+        iface = (iface != null) ? iface : NO_INTERFACE_NAME;
+        v4addr = (v4addr != null) ? v4addr : NO_IPV4_ADDRESS;
+        v4gateway = (v4gateway != null) ? v4gateway : NO_IPV4_GATEWAY;
+        v6gws = (v6gws != null) ? v6gws : new ArrayList<>();
+
+        final String logmsg = String.format("setUpstreamParameters(%s, %s, %s, [%s])",
+                iface, v4addr, v4gateway, String.join(",", v6gws));
+
+        final CbResults results = new CbResults();
+        try {
+            mOffloadControl.setUpstreamParameters(
+                    iface, v4addr, v4gateway, v6gws,
+                    (boolean success, String errMsg) -> {
+                        results.mSuccess = success;
+                        results.mErrMsg = errMsg;
+                    });
+        } catch (RemoteException e) {
+            record(logmsg, e);
+            return false;
+        }
+
+        record(logmsg, results);
+        return results.mSuccess;
+    }
+
+    /** Add downstream prefix to offload management process. */
+    public boolean addDownstreamPrefix(String ifname, String prefix) {
+        final String logmsg = String.format("addDownstreamPrefix(%s, %s)", ifname, prefix);
+
+        final CbResults results = new CbResults();
+        try {
+            mOffloadControl.addDownstream(ifname, prefix,
+                    (boolean success, String errMsg) -> {
+                        results.mSuccess = success;
+                        results.mErrMsg = errMsg;
+                    });
+        } catch (RemoteException e) {
+            record(logmsg, e);
+            return false;
+        }
+
+        record(logmsg, results);
+        return results.mSuccess;
+    }
+
+    /** Remove downstream prefix from offload management process. */
+    public boolean removeDownstreamPrefix(String ifname, String prefix) {
+        final String logmsg = String.format("removeDownstreamPrefix(%s, %s)", ifname, prefix);
+
+        final CbResults results = new CbResults();
+        try {
+            mOffloadControl.removeDownstream(ifname, prefix,
+                    (boolean success, String errMsg) -> {
+                        results.mSuccess = success;
+                        results.mErrMsg = errMsg;
+                    });
+        } catch (RemoteException e) {
+            record(logmsg, e);
+            return false;
+        }
+
+        record(logmsg, results);
+        return results.mSuccess;
+    }
+
+    private void record(String msg, Throwable t) {
+        mLog.e(msg + YIELDS + "exception: " + t);
+    }
+
+    private void record(String msg, CbResults results) {
+        final String logmsg = msg + YIELDS + results;
+        if (!results.mSuccess) {
+            mLog.e(logmsg);
+        } else {
+            mLog.log(logmsg);
+        }
+    }
+
+    private static class TetheringOffloadCallback extends ITetheringOffloadCallback.Stub {
+        public final Handler handler;
+        public final ControlCallback controlCb;
+        public final SharedLog log;
+
+        TetheringOffloadCallback(Handler h, ControlCallback cb, SharedLog sharedLog) {
+            handler = h;
+            controlCb = cb;
+            log = sharedLog;
+        }
+
+        @Override
+        public void onEvent(int event) {
+            handler.post(() -> {
+                switch (event) {
+                    case OffloadCallbackEvent.OFFLOAD_STARTED:
+                        controlCb.onStarted();
+                        break;
+                    case OffloadCallbackEvent.OFFLOAD_STOPPED_ERROR:
+                        controlCb.onStoppedError();
+                        break;
+                    case OffloadCallbackEvent.OFFLOAD_STOPPED_UNSUPPORTED:
+                        controlCb.onStoppedUnsupported();
+                        break;
+                    case OffloadCallbackEvent.OFFLOAD_SUPPORT_AVAILABLE:
+                        controlCb.onSupportAvailable();
+                        break;
+                    case OffloadCallbackEvent.OFFLOAD_STOPPED_LIMIT_REACHED:
+                        controlCb.onStoppedLimitReached();
+                        break;
+                    default:
+                        log.e("Unsupported OffloadCallbackEvent: " + event);
+                }
+            });
+        }
+
+        @Override
+        public void updateTimeout(NatTimeoutUpdate params) {
+            handler.post(() -> {
+                controlCb.onNatTimeoutUpdate(
+                        networkProtocolToOsConstant(params.proto),
+                        params.src.addr, uint16(params.src.port),
+                        params.dst.addr, uint16(params.dst.port));
+            });
+        }
+    }
+
+    private static int networkProtocolToOsConstant(int proto) {
+        switch (proto) {
+            case NetworkProtocol.TCP: return OsConstants.IPPROTO_TCP;
+            case NetworkProtocol.UDP: return OsConstants.IPPROTO_UDP;
+            default:
+                // The caller checks this value and will log an error. Just make
+                // sure it won't collide with valid OsContants.IPPROTO_* values.
+                return -Math.abs(proto);
+        }
+    }
+
+    private static class CbResults {
+        boolean mSuccess;
+        String mErrMsg;
+
+        @Override
+        public String toString() {
+            if (mSuccess) {
+                return "ok";
+            } else {
+                return "fail: " + mErrMsg;
+            }
+        }
+    }
+}
diff --git a/Tethering/src/com/android/networkstack/tethering/PrivateAddressCoordinator.java b/Tethering/src/com/android/networkstack/tethering/PrivateAddressCoordinator.java
new file mode 100644
index 0000000..4f616cd
--- /dev/null
+++ b/Tethering/src/com/android/networkstack/tethering/PrivateAddressCoordinator.java
@@ -0,0 +1,416 @@
+/*
+ * Copyright (C) 2020 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package com.android.networkstack.tethering;
+
+import static android.net.NetworkCapabilities.TRANSPORT_VPN;
+import static android.net.TetheringManager.TETHERING_BLUETOOTH;
+import static android.net.TetheringManager.TETHERING_WIFI_P2P;
+import static android.net.util.PrefixUtils.asIpPrefix;
+
+import static com.android.net.module.util.Inet4AddressUtils.inet4AddressToIntHTH;
+import static com.android.net.module.util.Inet4AddressUtils.intToInet4AddressHTH;
+import static com.android.net.module.util.Inet4AddressUtils.prefixLengthToV4NetmaskIntHTH;
+
+import static java.util.Arrays.asList;
+
+import android.content.Context;
+import android.net.ConnectivityManager;
+import android.net.IpPrefix;
+import android.net.LinkAddress;
+import android.net.Network;
+import android.net.ip.IpServer;
+import android.util.ArrayMap;
+import android.util.ArraySet;
+import android.util.SparseArray;
+
+import androidx.annotation.NonNull;
+import androidx.annotation.Nullable;
+
+import com.android.internal.annotations.VisibleForTesting;
+import com.android.internal.util.IndentingPrintWriter;
+
+import java.net.Inet4Address;
+import java.net.InetAddress;
+import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.HashSet;
+import java.util.List;
+import java.util.Random;
+import java.util.Set;
+
+/**
+ * This class coordinate IP addresses conflict problem.
+ *
+ * Tethering downstream IP addresses may conflict with network assigned addresses. This
+ * coordinator is responsible for recording all of network assigned addresses and dispatched
+ * free address to downstream interfaces.
+ *
+ * This class is not thread-safe and should be accessed on the same tethering internal thread.
+ * @hide
+ */
+public class PrivateAddressCoordinator {
+    public static final int PREFIX_LENGTH = 24;
+
+    // Upstream monitor would be stopped when tethering is down. When tethering restart, downstream
+    // address may be requested before coordinator get current upstream notification. To ensure
+    // coordinator do not select conflict downstream prefix, mUpstreamPrefixMap would not be cleared
+    // when tethering is down. Instead tethering would remove all deprecated upstreams from
+    // mUpstreamPrefixMap when tethering is starting. See #maybeRemoveDeprecatedUpstreams().
+    private final ArrayMap<Network, List<IpPrefix>> mUpstreamPrefixMap;
+    private final ArraySet<IpServer> mDownstreams;
+    private static final String LEGACY_WIFI_P2P_IFACE_ADDRESS = "192.168.49.1/24";
+    private static final String LEGACY_BLUETOOTH_IFACE_ADDRESS = "192.168.44.1/24";
+    private final List<IpPrefix> mTetheringPrefixes;
+    private final ConnectivityManager mConnectivityMgr;
+    private final TetheringConfiguration mConfig;
+    // keyed by downstream type(TetheringManager.TETHERING_*).
+    private final SparseArray<LinkAddress> mCachedAddresses;
+
+    public PrivateAddressCoordinator(Context context, TetheringConfiguration config) {
+        mDownstreams = new ArraySet<>();
+        mUpstreamPrefixMap = new ArrayMap<>();
+        mConnectivityMgr = (ConnectivityManager) context.getSystemService(
+                Context.CONNECTIVITY_SERVICE);
+        mConfig = config;
+        mCachedAddresses = new SparseArray<>();
+        // Reserved static addresses for bluetooth and wifi p2p.
+        mCachedAddresses.put(TETHERING_BLUETOOTH, new LinkAddress(LEGACY_BLUETOOTH_IFACE_ADDRESS));
+        mCachedAddresses.put(TETHERING_WIFI_P2P, new LinkAddress(LEGACY_WIFI_P2P_IFACE_ADDRESS));
+
+        mTetheringPrefixes = new ArrayList<>(Arrays.asList(new IpPrefix("192.168.0.0/16")));
+        if (config.isSelectAllPrefixRangeEnabled()) {
+            mTetheringPrefixes.add(new IpPrefix("172.16.0.0/12"));
+            mTetheringPrefixes.add(new IpPrefix("10.0.0.0/8"));
+        }
+    }
+
+    /**
+     * Record a new upstream IpPrefix which may conflict with tethering downstreams.
+     * The downstreams will be notified if a conflict is found. When updateUpstreamPrefix is called,
+     * UpstreamNetworkState must have an already populated LinkProperties.
+     */
+    public void updateUpstreamPrefix(final UpstreamNetworkState ns) {
+        // Do not support VPN as upstream. Normally, networkCapabilities is not expected to be null,
+        // but just checking to be sure.
+        if (ns.networkCapabilities != null && ns.networkCapabilities.hasTransport(TRANSPORT_VPN)) {
+            removeUpstreamPrefix(ns.network);
+            return;
+        }
+
+        final ArrayList<IpPrefix> ipv4Prefixes = getIpv4Prefixes(
+                ns.linkProperties.getAllLinkAddresses());
+        if (ipv4Prefixes.isEmpty()) {
+            removeUpstreamPrefix(ns.network);
+            return;
+        }
+
+        mUpstreamPrefixMap.put(ns.network, ipv4Prefixes);
+        handleMaybePrefixConflict(ipv4Prefixes);
+    }
+
+    private ArrayList<IpPrefix> getIpv4Prefixes(final List<LinkAddress> linkAddresses) {
+        final ArrayList<IpPrefix> list = new ArrayList<>();
+        for (LinkAddress address : linkAddresses) {
+            if (!address.isIpv4()) continue;
+
+            list.add(asIpPrefix(address));
+        }
+
+        return list;
+    }
+
+    private void handleMaybePrefixConflict(final List<IpPrefix> prefixes) {
+        for (IpServer downstream : mDownstreams) {
+            final IpPrefix target = getDownstreamPrefix(downstream);
+
+            for (IpPrefix source : prefixes) {
+                if (isConflictPrefix(source, target)) {
+                    downstream.sendMessage(IpServer.CMD_NOTIFY_PREFIX_CONFLICT);
+                    break;
+                }
+            }
+        }
+    }
+
+    /** Remove IpPrefix records corresponding to input network. */
+    public void removeUpstreamPrefix(final Network network) {
+        mUpstreamPrefixMap.remove(network);
+    }
+
+    /**
+     * Maybe remove deprecated upstream records, this would be called once tethering started without
+     * any exiting tethered downstream.
+     */
+    public void maybeRemoveDeprecatedUpstreams() {
+        if (mUpstreamPrefixMap.isEmpty()) return;
+
+        // Remove all upstreams that are no longer valid networks
+        final Set<Network> toBeRemoved = new HashSet<>(mUpstreamPrefixMap.keySet());
+        toBeRemoved.removeAll(asList(mConnectivityMgr.getAllNetworks()));
+
+        mUpstreamPrefixMap.removeAll(toBeRemoved);
+    }
+
+    /**
+     * Pick a random available address and mark its prefix as in use for the provided IpServer,
+     * returns null if there is no available address.
+     */
+    @Nullable
+    public LinkAddress requestDownstreamAddress(final IpServer ipServer, boolean useLastAddress) {
+        if (mConfig.shouldEnableWifiP2pDedicatedIp()
+                && ipServer.interfaceType() == TETHERING_WIFI_P2P) {
+            return new LinkAddress(LEGACY_WIFI_P2P_IFACE_ADDRESS);
+        }
+
+        final LinkAddress cachedAddress = mCachedAddresses.get(ipServer.interfaceType());
+        if (useLastAddress && cachedAddress != null
+                && !isConflictWithUpstream(asIpPrefix(cachedAddress))) {
+            mDownstreams.add(ipServer);
+            return cachedAddress;
+        }
+
+        for (IpPrefix prefixRange : mTetheringPrefixes) {
+            final LinkAddress newAddress = chooseDownstreamAddress(prefixRange);
+            if (newAddress != null) {
+                mDownstreams.add(ipServer);
+                mCachedAddresses.put(ipServer.interfaceType(), newAddress);
+                return newAddress;
+            }
+        }
+
+        // No available address.
+        return null;
+    }
+
+    private int getPrefixBaseAddress(final IpPrefix prefix) {
+        return inet4AddressToIntHTH((Inet4Address) prefix.getAddress());
+    }
+
+    /**
+     * Check whether input prefix conflict with upstream prefixes or in-use downstream prefixes.
+     * If yes, return one of them.
+     */
+    private IpPrefix getConflictPrefix(final IpPrefix prefix) {
+        final IpPrefix upstream = getConflictWithUpstream(prefix);
+        if (upstream != null) return upstream;
+
+        return getInUseDownstreamPrefix(prefix);
+    }
+
+    // Get the next non-conflict sub prefix. E.g: To get next sub prefix from 10.0.0.0/8, if the
+    // previously selected prefix is 10.20.42.0/24(subPrefix: 0.20.42.0) and the conflicting prefix
+    // is 10.16.0.0/20 (10.16.0.0 ~ 10.16.15.255), then the max address under subPrefix is
+    // 0.16.15.255 and the next subPrefix is 0.16.16.255/24 (0.16.15.255 + 0.0.1.0).
+    // Note: the sub address 0.0.0.255 here is fine to be any value that it will be replaced as
+    // selected random sub address later.
+    private int getNextSubPrefix(final IpPrefix conflictPrefix, final int prefixRangeMask) {
+        final int suffixMask = ~prefixLengthToV4NetmaskIntHTH(conflictPrefix.getPrefixLength());
+        // The largest offset within the prefix assignment block that still conflicts with
+        // conflictPrefix.
+        final int maxConflict =
+                (getPrefixBaseAddress(conflictPrefix) | suffixMask) & ~prefixRangeMask;
+
+        final int prefixMask = prefixLengthToV4NetmaskIntHTH(PREFIX_LENGTH);
+        // Pick a sub prefix a full prefix (1 << (32 - PREFIX_LENGTH) addresses) greater than
+        // maxConflict. This ensures that the selected prefix never overlaps with conflictPrefix.
+        // There is no need to mask the result with PREFIX_LENGTH bits because this is done by
+        // findAvailablePrefixFromRange when it constructs the prefix.
+        return maxConflict + (1 << (32 - PREFIX_LENGTH));
+    }
+
+    private LinkAddress chooseDownstreamAddress(final IpPrefix prefixRange) {
+        // The netmask of the prefix assignment block (e.g., 0xfff00000 for 172.16.0.0/12).
+        final int prefixRangeMask = prefixLengthToV4NetmaskIntHTH(prefixRange.getPrefixLength());
+
+        // The zero address in the block (e.g., 0xac100000 for 172.16.0.0/12).
+        final int baseAddress = getPrefixBaseAddress(prefixRange);
+
+        // The subnet mask corresponding to PREFIX_LENGTH.
+        final int prefixMask = prefixLengthToV4NetmaskIntHTH(PREFIX_LENGTH);
+
+        // The offset within prefixRange of a randomly-selected prefix of length PREFIX_LENGTH.
+        // This may not be the prefix of the address returned by this method:
+        // - If it is already in use, the method will return an address in another prefix.
+        // - If all prefixes within prefixRange are in use, the method will return null. For
+        // example, for a /24 prefix within 172.26.0.0/12, this will be a multiple of 256 in
+        // [0, 1048576). In other words, a random 32-bit number with mask 0x000fff00.
+        //
+        // prefixRangeMask is required to ensure no wrapping. For example, consider:
+        // - prefixRange 127.0.0.0/8
+        // - randomPrefixStart 127.255.255.0
+        // - A conflicting prefix of 127.255.254.0/23
+        // In this case without prefixRangeMask, getNextSubPrefix would return 128.0.0.0, which
+        // means the "start < end" check in findAvailablePrefixFromRange would not reject the prefix
+        // because Java doesn't have unsigned integers, so 128.0.0.0 = 0x80000000 = -2147483648
+        // is less than 127.0.0.0 = 0x7f000000 = 2130706432.
+        //
+        // Additionally, it makes debug output easier to read by making the numbers smaller.
+        final int randomPrefixStart = getRandomInt() & ~prefixRangeMask & prefixMask;
+
+        // A random offset within the prefix. Used to determine the local address once the prefix
+        // is selected. It does not result in an IPv4 address ending in .0, .1, or .255
+        // For a PREFIX_LENGTH of 255, this is a number between 2 and 254.
+        final int subAddress = getSanitizedSubAddr(~prefixMask);
+
+        // Find a prefix length PREFIX_LENGTH between randomPrefixStart and the end of the block,
+        // such that the prefix does not conflict with any upstream.
+        IpPrefix downstreamPrefix = findAvailablePrefixFromRange(
+                 randomPrefixStart, (~prefixRangeMask) + 1, baseAddress, prefixRangeMask);
+        if (downstreamPrefix != null) return getLinkAddress(downstreamPrefix, subAddress);
+
+        // If that failed, do the same, but between 0 and randomPrefixStart.
+        downstreamPrefix = findAvailablePrefixFromRange(
+                0, randomPrefixStart, baseAddress, prefixRangeMask);
+
+        return getLinkAddress(downstreamPrefix, subAddress);
+    }
+
+    private LinkAddress getLinkAddress(final IpPrefix prefix, final int subAddress) {
+        if (prefix == null) return null;
+
+        final InetAddress address = intToInet4AddressHTH(getPrefixBaseAddress(prefix) | subAddress);
+        return new LinkAddress(address, PREFIX_LENGTH);
+    }
+
+    private IpPrefix findAvailablePrefixFromRange(final int start, final int end,
+            final int baseAddress, final int prefixRangeMask) {
+        int newSubPrefix = start;
+        while (newSubPrefix < end) {
+            final InetAddress address = intToInet4AddressHTH(baseAddress | newSubPrefix);
+            final IpPrefix prefix = new IpPrefix(address, PREFIX_LENGTH);
+
+            final IpPrefix conflictPrefix = getConflictPrefix(prefix);
+
+            if (conflictPrefix == null) return prefix;
+
+            newSubPrefix = getNextSubPrefix(conflictPrefix, prefixRangeMask);
+        }
+
+        return null;
+    }
+
+    /** Get random int which could be used to generate random address. */
+    @VisibleForTesting
+    public int getRandomInt() {
+        return (new Random()).nextInt();
+    }
+
+    /** Get random subAddress and avoid selecting x.x.x.0, x.x.x.1 and x.x.x.255 address. */
+    private int getSanitizedSubAddr(final int subAddrMask) {
+        final int randomSubAddr = getRandomInt() & subAddrMask;
+        // If prefix length > 30, the selecting speace would be less than 4 which may be hard to
+        // avoid 3 consecutive address.
+        if (PREFIX_LENGTH > 30) return randomSubAddr;
+
+        // TODO: maybe it is not necessary to avoid .0, .1 and .255 address because tethering
+        // address would not be conflicted. This code only works because PREFIX_LENGTH is not longer
+        // than 24
+        final int candidate = randomSubAddr & 0xff;
+        if (candidate == 0 || candidate == 1 || candidate == 255) {
+            return (randomSubAddr & 0xfffffffc) + 2;
+        }
+
+        return randomSubAddr;
+    }
+
+    /** Release downstream record for IpServer. */
+    public void releaseDownstream(final IpServer ipServer) {
+        mDownstreams.remove(ipServer);
+    }
+
+    /** Clear current upstream prefixes records. */
+    public void clearUpstreamPrefixes() {
+        mUpstreamPrefixMap.clear();
+    }
+
+    private IpPrefix getConflictWithUpstream(final IpPrefix prefix) {
+        for (int i = 0; i < mUpstreamPrefixMap.size(); i++) {
+            final List<IpPrefix> list = mUpstreamPrefixMap.valueAt(i);
+            for (IpPrefix upstream : list) {
+                if (isConflictPrefix(prefix, upstream)) return upstream;
+            }
+        }
+        return null;
+    }
+
+    private boolean isConflictWithUpstream(final IpPrefix prefix) {
+        return getConflictWithUpstream(prefix) != null;
+    }
+
+    private boolean isConflictPrefix(final IpPrefix prefix1, final IpPrefix prefix2) {
+        if (prefix2.getPrefixLength() < prefix1.getPrefixLength()) {
+            return prefix2.contains(prefix1.getAddress());
+        }
+
+        return prefix1.contains(prefix2.getAddress());
+    }
+
+    // InUse Prefixes are prefixes of mCachedAddresses which are active downstream addresses, last
+    // downstream addresses(reserved for next time) and static addresses(e.g. bluetooth, wifi p2p).
+    private IpPrefix getInUseDownstreamPrefix(final IpPrefix prefix) {
+        for (int i = 0; i < mCachedAddresses.size(); i++) {
+            final IpPrefix downstream = asIpPrefix(mCachedAddresses.valueAt(i));
+            if (isConflictPrefix(prefix, downstream)) return downstream;
+        }
+
+        // IpServer may use manually-defined address (mStaticIpv4ServerAddr) which does not include
+        // in mCachedAddresses.
+        for (IpServer downstream : mDownstreams) {
+            final IpPrefix target = getDownstreamPrefix(downstream);
+
+            if (isConflictPrefix(prefix, target)) return target;
+        }
+
+        return null;
+    }
+
+    @NonNull
+    private IpPrefix getDownstreamPrefix(final IpServer downstream) {
+        final LinkAddress address = downstream.getAddress();
+
+        return asIpPrefix(address);
+    }
+
+    void dump(final IndentingPrintWriter pw) {
+        pw.println("mTetheringPrefixes:");
+        pw.increaseIndent();
+        for (IpPrefix prefix : mTetheringPrefixes) {
+            pw.println(prefix);
+        }
+        pw.decreaseIndent();
+
+        pw.println("mUpstreamPrefixMap:");
+        pw.increaseIndent();
+        for (int i = 0; i < mUpstreamPrefixMap.size(); i++) {
+            pw.println(mUpstreamPrefixMap.keyAt(i) + " - " + mUpstreamPrefixMap.valueAt(i));
+        }
+        pw.decreaseIndent();
+
+        pw.println("mDownstreams:");
+        pw.increaseIndent();
+        for (IpServer ipServer : mDownstreams) {
+            pw.println(ipServer.interfaceType() + " - " + ipServer.getAddress());
+        }
+        pw.decreaseIndent();
+
+        pw.println("mCachedAddresses:");
+        pw.increaseIndent();
+        for (int i = 0; i < mCachedAddresses.size(); i++) {
+            pw.println(mCachedAddresses.keyAt(i) + " - " + mCachedAddresses.valueAt(i));
+        }
+        pw.decreaseIndent();
+    }
+}
diff --git a/Tethering/src/com/android/networkstack/tethering/Tethering.java b/Tethering/src/com/android/networkstack/tethering/Tethering.java
new file mode 100644
index 0000000..5a0c5b0
--- /dev/null
+++ b/Tethering/src/com/android/networkstack/tethering/Tethering.java
@@ -0,0 +1,2427 @@
+/*
+ * Copyright (C) 2010 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.android.networkstack.tethering;
+
+import static android.Manifest.permission.NETWORK_SETTINGS;
+import static android.Manifest.permission.NETWORK_STACK;
+import static android.content.pm.PackageManager.GET_ACTIVITIES;
+import static android.content.pm.PackageManager.PERMISSION_GRANTED;
+import static android.hardware.usb.UsbManager.USB_CONFIGURED;
+import static android.hardware.usb.UsbManager.USB_CONNECTED;
+import static android.hardware.usb.UsbManager.USB_FUNCTION_NCM;
+import static android.hardware.usb.UsbManager.USB_FUNCTION_RNDIS;
+import static android.net.ConnectivityManager.ACTION_RESTRICT_BACKGROUND_CHANGED;
+import static android.net.ConnectivityManager.CONNECTIVITY_ACTION;
+import static android.net.ConnectivityManager.EXTRA_NETWORK_INFO;
+import static android.net.NetworkStack.PERMISSION_MAINLINE_NETWORK_STACK;
+import static android.net.TetheringManager.ACTION_TETHER_STATE_CHANGED;
+import static android.net.TetheringManager.EXTRA_ACTIVE_LOCAL_ONLY;
+import static android.net.TetheringManager.EXTRA_ACTIVE_TETHER;
+import static android.net.TetheringManager.EXTRA_AVAILABLE_TETHER;
+import static android.net.TetheringManager.EXTRA_ERRORED_TETHER;
+import static android.net.TetheringManager.TETHERING_BLUETOOTH;
+import static android.net.TetheringManager.TETHERING_ETHERNET;
+import static android.net.TetheringManager.TETHERING_INVALID;
+import static android.net.TetheringManager.TETHERING_NCM;
+import static android.net.TetheringManager.TETHERING_USB;
+import static android.net.TetheringManager.TETHERING_WIFI;
+import static android.net.TetheringManager.TETHERING_WIFI_P2P;
+import static android.net.TetheringManager.TETHERING_WIGIG;
+import static android.net.TetheringManager.TETHER_ERROR_INTERNAL_ERROR;
+import static android.net.TetheringManager.TETHER_ERROR_NO_ERROR;
+import static android.net.TetheringManager.TETHER_ERROR_SERVICE_UNAVAIL;
+import static android.net.TetheringManager.TETHER_ERROR_UNAVAIL_IFACE;
+import static android.net.TetheringManager.TETHER_ERROR_UNKNOWN_IFACE;
+import static android.net.TetheringManager.TETHER_ERROR_UNKNOWN_TYPE;
+import static android.net.TetheringManager.TETHER_HARDWARE_OFFLOAD_FAILED;
+import static android.net.TetheringManager.TETHER_HARDWARE_OFFLOAD_STARTED;
+import static android.net.TetheringManager.TETHER_HARDWARE_OFFLOAD_STOPPED;
+import static android.net.util.TetheringMessageBase.BASE_MAIN_SM;
+import static android.net.wifi.WifiManager.EXTRA_WIFI_AP_INTERFACE_NAME;
+import static android.net.wifi.WifiManager.EXTRA_WIFI_AP_MODE;
+import static android.net.wifi.WifiManager.EXTRA_WIFI_AP_STATE;
+import static android.net.wifi.WifiManager.IFACE_IP_MODE_CONFIGURATION_ERROR;
+import static android.net.wifi.WifiManager.IFACE_IP_MODE_LOCAL_ONLY;
+import static android.net.wifi.WifiManager.IFACE_IP_MODE_TETHERED;
+import static android.net.wifi.WifiManager.IFACE_IP_MODE_UNSPECIFIED;
+import static android.net.wifi.WifiManager.WIFI_AP_STATE_DISABLED;
+import static android.telephony.CarrierConfigManager.ACTION_CARRIER_CONFIG_CHANGED;
+import static android.telephony.SubscriptionManager.INVALID_SUBSCRIPTION_ID;
+
+import static com.android.networkstack.tethering.TetheringNotificationUpdater.DOWNSTREAM_NONE;
+
+import android.app.usage.NetworkStatsManager;
+import android.bluetooth.BluetoothAdapter;
+import android.bluetooth.BluetoothPan;
+import android.bluetooth.BluetoothProfile;
+import android.bluetooth.BluetoothProfile.ServiceListener;
+import android.content.BroadcastReceiver;
+import android.content.Context;
+import android.content.Intent;
+import android.content.IntentFilter;
+import android.content.pm.PackageManager;
+import android.hardware.usb.UsbManager;
+import android.net.ConnectivityManager;
+import android.net.EthernetManager;
+import android.net.IIntResultListener;
+import android.net.INetd;
+import android.net.ITetheringEventCallback;
+import android.net.IpPrefix;
+import android.net.LinkAddress;
+import android.net.LinkProperties;
+import android.net.Network;
+import android.net.NetworkCapabilities;
+import android.net.NetworkInfo;
+import android.net.TetherStatesParcel;
+import android.net.TetheredClient;
+import android.net.TetheringCallbackStartedParcel;
+import android.net.TetheringConfigurationParcel;
+import android.net.TetheringRequestParcel;
+import android.net.ip.IpServer;
+import android.net.shared.NetdUtils;
+import android.net.util.BaseNetdUnsolicitedEventListener;
+import android.net.util.InterfaceSet;
+import android.net.util.PrefixUtils;
+import android.net.util.SharedLog;
+import android.net.util.TetheringUtils;
+import android.net.util.VersionedBroadcastListener;
+import android.net.wifi.WifiClient;
+import android.net.wifi.WifiManager;
+import android.net.wifi.p2p.WifiP2pGroup;
+import android.net.wifi.p2p.WifiP2pInfo;
+import android.net.wifi.p2p.WifiP2pManager;
+import android.os.Binder;
+import android.os.Bundle;
+import android.os.Handler;
+import android.os.Looper;
+import android.os.Message;
+import android.os.RemoteCallbackList;
+import android.os.RemoteException;
+import android.os.ResultReceiver;
+import android.os.ServiceSpecificException;
+import android.os.UserHandle;
+import android.os.UserManager;
+import android.provider.Settings;
+import android.telephony.PhoneStateListener;
+import android.telephony.TelephonyManager;
+import android.text.TextUtils;
+import android.util.ArrayMap;
+import android.util.Log;
+import android.util.SparseArray;
+
+import androidx.annotation.NonNull;
+import androidx.annotation.Nullable;
+
+import com.android.internal.annotations.GuardedBy;
+import com.android.internal.annotations.VisibleForTesting;
+import com.android.internal.util.IndentingPrintWriter;
+import com.android.internal.util.MessageUtils;
+import com.android.internal.util.State;
+import com.android.internal.util.StateMachine;
+
+import java.io.FileDescriptor;
+import java.io.PrintWriter;
+import java.net.InetAddress;
+import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.Collection;
+import java.util.Collections;
+import java.util.Iterator;
+import java.util.LinkedHashSet;
+import java.util.List;
+import java.util.Set;
+import java.util.concurrent.Executor;
+import java.util.concurrent.RejectedExecutionException;
+
+/**
+ *
+ * This class holds much of the business logic to allow Android devices
+ * to act as IP gateways via USB, BT, and WiFi interfaces.
+ */
+public class Tethering {
+
+    private static final String TAG = Tethering.class.getSimpleName();
+    private static final boolean DBG = false;
+    private static final boolean VDBG = false;
+
+    private static final Class[] sMessageClasses = {
+            Tethering.class, TetherMainSM.class, IpServer.class
+    };
+    private static final SparseArray<String> sMagicDecoderRing =
+            MessageUtils.findMessageNames(sMessageClasses);
+    // Keep in sync with NETID_UNSET in system/netd/include/netid_client.h
+    private static final int NETID_UNSET = 0;
+
+    private static class TetherState {
+        public final IpServer ipServer;
+        public int lastState;
+        public int lastError;
+
+        TetherState(IpServer ipServer) {
+            this.ipServer = ipServer;
+            // Assume all state machines start out available and with no errors.
+            lastState = IpServer.STATE_AVAILABLE;
+            lastError = TETHER_ERROR_NO_ERROR;
+        }
+
+        public boolean isCurrentlyServing() {
+            switch (lastState) {
+                case IpServer.STATE_TETHERED:
+                case IpServer.STATE_LOCAL_ONLY:
+                    return true;
+                default:
+                    return false;
+            }
+        }
+    }
+
+    /**
+     * Cookie added when registering {@link android.net.TetheringManager.TetheringEventCallback}.
+     */
+    private static class CallbackCookie {
+        public final boolean hasListClientsPermission;
+
+        private CallbackCookie(boolean hasListClientsPermission) {
+            this.hasListClientsPermission = hasListClientsPermission;
+        }
+    }
+
+    private final SharedLog mLog = new SharedLog(TAG);
+    private final RemoteCallbackList<ITetheringEventCallback> mTetheringEventCallbacks =
+            new RemoteCallbackList<>();
+    // Currently active tethering requests per tethering type. Only one of each type can be
+    // requested at a time. After a tethering type is requested, the map keeps tethering parameters
+    // to be used after the interface comes up asynchronously.
+    private final SparseArray<TetheringRequestParcel> mActiveTetheringRequests =
+            new SparseArray<>();
+
+    // used to synchronize public access to members
+    // TODO(b/153621704): remove mPublicSync to make Tethering lock free
+    private final Object mPublicSync;
+    private final Context mContext;
+    private final ArrayMap<String, TetherState> mTetherStates;
+    private final BroadcastReceiver mStateReceiver;
+    private final Looper mLooper;
+    private final StateMachine mTetherMainSM;
+    private final OffloadController mOffloadController;
+    private final UpstreamNetworkMonitor mUpstreamNetworkMonitor;
+    // TODO: Figure out how to merge this and other downstream-tracking objects
+    // into a single coherent structure.
+    // Use LinkedHashSet for predictable ordering order for ConnectedClientsTracker.
+    private final LinkedHashSet<IpServer> mForwardedDownstreams;
+    private final VersionedBroadcastListener mCarrierConfigChange;
+    private final TetheringDependencies mDeps;
+    private final EntitlementManager mEntitlementMgr;
+    private final Handler mHandler;
+    private final INetd mNetd;
+    private final NetdCallback mNetdCallback;
+    private final UserRestrictionActionListener mTetheringRestriction;
+    private final ActiveDataSubIdListener mActiveDataSubIdListener;
+    private final ConnectedClientsTracker mConnectedClientsTracker;
+    private final TetheringThreadExecutor mExecutor;
+    private final TetheringNotificationUpdater mNotificationUpdater;
+    private final UserManager mUserManager;
+    private final BpfCoordinator mBpfCoordinator;
+    private final PrivateAddressCoordinator mPrivateAddressCoordinator;
+    private int mActiveDataSubId = INVALID_SUBSCRIPTION_ID;
+    // All the usage of mTetheringEventCallback should run in the same thread.
+    private ITetheringEventCallback mTetheringEventCallback = null;
+
+    private volatile TetheringConfiguration mConfig;
+    private InterfaceSet mCurrentUpstreamIfaceSet;
+
+    private boolean mRndisEnabled;       // track the RNDIS function enabled state
+    // True iff. WiFi tethering should be started when soft AP is ready.
+    private boolean mWifiTetherRequested;
+    private Network mTetherUpstream;
+    private TetherStatesParcel mTetherStatesParcel;
+    private boolean mDataSaverEnabled = false;
+    private String mWifiP2pTetherInterface = null;
+    private int mOffloadStatus = TETHER_HARDWARE_OFFLOAD_STOPPED;
+
+    @GuardedBy("mPublicSync")
+    private EthernetManager.TetheredInterfaceRequest mEthernetIfaceRequest;
+    @GuardedBy("mPublicSync")
+    private String mConfiguredEthernetIface;
+    @GuardedBy("mPublicSync")
+    private EthernetCallback mEthernetCallback;
+
+    public Tethering(TetheringDependencies deps) {
+        mLog.mark("Tethering.constructed");
+        mDeps = deps;
+        mContext = mDeps.getContext();
+        mNetd = mDeps.getINetd(mContext);
+        mLooper = mDeps.getTetheringLooper();
+        mNotificationUpdater = mDeps.getNotificationUpdater(mContext, mLooper);
+
+        mPublicSync = new Object();
+
+        mTetherStates = new ArrayMap<>();
+        mConnectedClientsTracker = new ConnectedClientsTracker();
+
+        mTetherMainSM = new TetherMainSM("TetherMain", mLooper, deps);
+        mTetherMainSM.start();
+
+        mHandler = mTetherMainSM.getHandler();
+        mOffloadController = mDeps.getOffloadController(mHandler, mLog,
+                new OffloadController.Dependencies() {
+
+                    @Override
+                    public TetheringConfiguration getTetherConfig() {
+                        return mConfig;
+                    }
+                });
+        mUpstreamNetworkMonitor = mDeps.getUpstreamNetworkMonitor(mContext, mTetherMainSM, mLog,
+                TetherMainSM.EVENT_UPSTREAM_CALLBACK);
+        mForwardedDownstreams = new LinkedHashSet<>();
+
+        IntentFilter filter = new IntentFilter();
+        filter.addAction(ACTION_CARRIER_CONFIG_CHANGED);
+        // EntitlementManager will send EVENT_UPSTREAM_PERMISSION_CHANGED when cellular upstream
+        // permission is changed according to entitlement check result.
+        mEntitlementMgr = mDeps.getEntitlementManager(mContext, mHandler, mLog,
+                () -> mTetherMainSM.sendMessage(
+                TetherMainSM.EVENT_UPSTREAM_PERMISSION_CHANGED));
+        mEntitlementMgr.setOnUiEntitlementFailedListener((int downstream) -> {
+            mLog.log("OBSERVED UiEnitlementFailed");
+            stopTethering(downstream);
+        });
+        mEntitlementMgr.setTetheringConfigurationFetcher(() -> {
+            return mConfig;
+        });
+
+        mCarrierConfigChange = new VersionedBroadcastListener(
+                "CarrierConfigChangeListener", mContext, mHandler, filter,
+                (Intent ignored) -> {
+                    mLog.log("OBSERVED carrier config change");
+                    updateConfiguration();
+                    mEntitlementMgr.reevaluateSimCardProvisioning(mConfig);
+                });
+
+        mStateReceiver = new StateReceiver();
+
+        mUserManager = (UserManager) mContext.getSystemService(Context.USER_SERVICE);
+        mTetheringRestriction = new UserRestrictionActionListener(
+                mUserManager, this, mNotificationUpdater);
+        mExecutor = new TetheringThreadExecutor(mHandler);
+        mActiveDataSubIdListener = new ActiveDataSubIdListener(mExecutor);
+        mNetdCallback = new NetdCallback();
+
+        // Load tethering configuration.
+        updateConfiguration();
+        // It is OK for the configuration to be passed to the PrivateAddressCoordinator at
+        // construction time because the only part of the configuration it uses is
+        // shouldEnableWifiP2pDedicatedIp(), and currently do not support changing that.
+        mPrivateAddressCoordinator = mDeps.getPrivateAddressCoordinator(mContext, mConfig);
+
+        // Must be initialized after tethering configuration is loaded because BpfCoordinator
+        // constructor needs to use the configuration.
+        mBpfCoordinator = mDeps.getBpfCoordinator(
+                new BpfCoordinator.Dependencies() {
+                    @NonNull
+                    public Handler getHandler() {
+                        return mHandler;
+                    }
+
+                    @NonNull
+                    public INetd getNetd() {
+                        return mNetd;
+                    }
+
+                    @NonNull
+                    public NetworkStatsManager getNetworkStatsManager() {
+                        return mContext.getSystemService(NetworkStatsManager.class);
+                    }
+
+                    @NonNull
+                    public SharedLog getSharedLog() {
+                        return mLog;
+                    }
+
+                    @Nullable
+                    public TetheringConfiguration getTetherConfig() {
+                        return mConfig;
+                    }
+                });
+
+        startStateMachineUpdaters();
+    }
+
+    /**
+     * Start to register callbacks.
+     * Call this function when tethering is ready to handle callback events.
+     */
+    private void startStateMachineUpdaters() {
+        try {
+            mNetd.registerUnsolicitedEventListener(mNetdCallback);
+        } catch (RemoteException e) {
+            mLog.e("Unable to register netd UnsolicitedEventListener");
+        }
+        mCarrierConfigChange.startListening();
+        mContext.getSystemService(TelephonyManager.class).listen(mActiveDataSubIdListener,
+                PhoneStateListener.LISTEN_ACTIVE_DATA_SUBSCRIPTION_ID_CHANGE);
+
+        IntentFilter filter = new IntentFilter();
+        filter.addAction(UsbManager.ACTION_USB_STATE);
+        filter.addAction(CONNECTIVITY_ACTION);
+        filter.addAction(WifiManager.WIFI_AP_STATE_CHANGED_ACTION);
+        filter.addAction(Intent.ACTION_CONFIGURATION_CHANGED);
+        filter.addAction(WifiP2pManager.WIFI_P2P_CONNECTION_CHANGED_ACTION);
+        filter.addAction(UserManager.ACTION_USER_RESTRICTIONS_CHANGED);
+        filter.addAction(ACTION_RESTRICT_BACKGROUND_CHANGED);
+        mContext.registerReceiver(mStateReceiver, filter, null, mHandler);
+
+        final IntentFilter noUpstreamFilter = new IntentFilter();
+        noUpstreamFilter.addAction(TetheringNotificationUpdater.ACTION_DISABLE_TETHERING);
+        mContext.registerReceiver(
+                mStateReceiver, noUpstreamFilter, PERMISSION_MAINLINE_NETWORK_STACK, mHandler);
+
+        final WifiManager wifiManager = getWifiManager();
+        if (wifiManager != null) {
+            wifiManager.registerSoftApCallback(mExecutor, new TetheringSoftApCallback());
+        }
+
+        startTrackDefaultNetwork();
+    }
+
+    private class TetheringThreadExecutor implements Executor {
+        private final Handler mTetherHandler;
+        TetheringThreadExecutor(Handler handler) {
+            mTetherHandler = handler;
+        }
+        @Override
+        public void execute(Runnable command) {
+            if (!mTetherHandler.post(command)) {
+                throw new RejectedExecutionException(mTetherHandler + " is shutting down");
+            }
+        }
+    }
+
+    private class ActiveDataSubIdListener extends PhoneStateListener {
+        ActiveDataSubIdListener(Executor executor) {
+            super(executor);
+        }
+
+        @Override
+        public void onActiveDataSubscriptionIdChanged(int subId) {
+            mLog.log("OBSERVED active data subscription change, from " + mActiveDataSubId
+                    + " to " + subId);
+            if (subId == mActiveDataSubId) return;
+
+            mActiveDataSubId = subId;
+            updateConfiguration();
+            mNotificationUpdater.onActiveDataSubscriptionIdChanged(subId);
+            // To avoid launching unexpected provisioning checks, ignore re-provisioning
+            // when no CarrierConfig loaded yet. Assume reevaluateSimCardProvisioning()
+            // will be triggered again when CarrierConfig is loaded.
+            if (mEntitlementMgr.getCarrierConfig(mConfig) != null) {
+                mEntitlementMgr.reevaluateSimCardProvisioning(mConfig);
+            } else {
+                mLog.log("IGNORED reevaluate provisioning, no carrier config loaded");
+            }
+        }
+    }
+
+    private WifiManager getWifiManager() {
+        return (WifiManager) mContext.getSystemService(Context.WIFI_SERVICE);
+    }
+
+    // NOTE: This is always invoked on the mLooper thread.
+    private void updateConfiguration() {
+        mConfig = mDeps.generateTetheringConfiguration(mContext, mLog, mActiveDataSubId);
+        mUpstreamNetworkMonitor.updateMobileRequiresDun(mConfig.isDunRequired);
+        reportConfigurationChanged(mConfig.toStableParcelable());
+    }
+
+    private void maybeDunSettingChanged() {
+        final boolean isDunRequired = TetheringConfiguration.checkDunRequired(mContext);
+        if (isDunRequired == mConfig.isDunRequired) return;
+        updateConfiguration();
+    }
+
+    private class NetdCallback extends BaseNetdUnsolicitedEventListener {
+        @Override
+        public void onInterfaceChanged(String ifName, boolean up) {
+            mHandler.post(() -> interfaceStatusChanged(ifName, up));
+        }
+
+        @Override
+        public void onInterfaceLinkStateChanged(String ifName, boolean up) {
+            mHandler.post(() -> interfaceLinkStateChanged(ifName, up));
+        }
+
+        @Override
+        public void onInterfaceAdded(String ifName) {
+            mHandler.post(() -> interfaceAdded(ifName));
+        }
+
+        @Override
+        public void onInterfaceRemoved(String ifName) {
+            mHandler.post(() -> interfaceRemoved(ifName));
+        }
+    }
+
+    private class TetheringSoftApCallback implements WifiManager.SoftApCallback {
+        // TODO: Remove onStateChanged override when this method has default on
+        // WifiManager#SoftApCallback interface.
+        // Wifi listener for state change of the soft AP
+        @Override
+        public void onStateChanged(final int state, final int failureReason) {
+            // Nothing
+        }
+
+        // Called by wifi when the number of soft AP clients changed.
+        @Override
+        public void onConnectedClientsChanged(final List<WifiClient> clients) {
+            updateConnectedClients(clients);
+        }
+    }
+
+    void interfaceStatusChanged(String iface, boolean up) {
+        // Never called directly: only called from interfaceLinkStateChanged.
+        // See NetlinkHandler.cpp: notifyInterfaceChanged.
+        if (VDBG) Log.d(TAG, "interfaceStatusChanged " + iface + ", " + up);
+        synchronized (mPublicSync) {
+            if (up) {
+                maybeTrackNewInterfaceLocked(iface);
+            } else {
+                if (ifaceNameToType(iface) == TETHERING_BLUETOOTH
+                        || ifaceNameToType(iface) == TETHERING_WIGIG) {
+                    stopTrackingInterfaceLocked(iface);
+                } else {
+                    // Ignore usb0 down after enabling RNDIS.
+                    // We will handle disconnect in interfaceRemoved.
+                    // Similarly, ignore interface down for WiFi.  We monitor WiFi AP status
+                    // through the WifiManager.WIFI_AP_STATE_CHANGED_ACTION intent.
+                    if (VDBG) Log.d(TAG, "ignore interface down for " + iface);
+                }
+            }
+        }
+    }
+
+    void interfaceLinkStateChanged(String iface, boolean up) {
+        interfaceStatusChanged(iface, up);
+    }
+
+    private int ifaceNameToType(String iface) {
+        final TetheringConfiguration cfg = mConfig;
+
+        if (cfg.isWifi(iface)) {
+            return TETHERING_WIFI;
+        } else if (cfg.isWigig(iface)) {
+            return TETHERING_WIGIG;
+        } else if (cfg.isWifiP2p(iface)) {
+            return TETHERING_WIFI_P2P;
+        } else if (cfg.isUsb(iface)) {
+            return TETHERING_USB;
+        } else if (cfg.isBluetooth(iface)) {
+            return TETHERING_BLUETOOTH;
+        } else if (cfg.isNcm(iface)) {
+            return TETHERING_NCM;
+        }
+        return TETHERING_INVALID;
+    }
+
+    void interfaceAdded(String iface) {
+        if (VDBG) Log.d(TAG, "interfaceAdded " + iface);
+        synchronized (mPublicSync) {
+            maybeTrackNewInterfaceLocked(iface);
+        }
+    }
+
+    void interfaceRemoved(String iface) {
+        if (VDBG) Log.d(TAG, "interfaceRemoved " + iface);
+        synchronized (mPublicSync) {
+            stopTrackingInterfaceLocked(iface);
+        }
+    }
+
+    void startTethering(final TetheringRequestParcel request, final IIntResultListener listener) {
+        mHandler.post(() -> {
+            final TetheringRequestParcel unfinishedRequest = mActiveTetheringRequests.get(
+                    request.tetheringType);
+            // If tethering is already enabled with a different request,
+            // disable before re-enabling.
+            if (unfinishedRequest != null
+                    && !TetheringUtils.isTetheringRequestEquals(unfinishedRequest, request)) {
+                enableTetheringInternal(request.tetheringType, false /* disabled */, null);
+                mEntitlementMgr.stopProvisioningIfNeeded(request.tetheringType);
+            }
+            mActiveTetheringRequests.put(request.tetheringType, request);
+
+            if (request.exemptFromEntitlementCheck) {
+                mEntitlementMgr.setExemptedDownstreamType(request.tetheringType);
+            } else {
+                mEntitlementMgr.startProvisioningIfNeeded(request.tetheringType,
+                        request.showProvisioningUi);
+            }
+            enableTetheringInternal(request.tetheringType, true /* enabled */, listener);
+        });
+    }
+
+    void stopTethering(int type) {
+        mHandler.post(() -> {
+            mActiveTetheringRequests.remove(type);
+
+            enableTetheringInternal(type, false /* disabled */, null);
+            mEntitlementMgr.stopProvisioningIfNeeded(type);
+        });
+    }
+
+    /**
+     * Enables or disables tethering for the given type. If provisioning is required, it will
+     * schedule provisioning rechecks for the specified interface.
+     */
+    private void enableTetheringInternal(int type, boolean enable,
+            final IIntResultListener listener) {
+        int result = TETHER_ERROR_NO_ERROR;
+        switch (type) {
+            case TETHERING_WIFI:
+                result = setWifiTethering(enable);
+                break;
+            case TETHERING_USB:
+                result = setUsbTethering(enable);
+                break;
+            case TETHERING_BLUETOOTH:
+                setBluetoothTethering(enable, listener);
+                break;
+            case TETHERING_NCM:
+                result = setNcmTethering(enable);
+                break;
+            case TETHERING_ETHERNET:
+                result = setEthernetTethering(enable);
+                break;
+            default:
+                Log.w(TAG, "Invalid tether type.");
+                result = TETHER_ERROR_UNKNOWN_TYPE;
+        }
+
+        // The result of Bluetooth tethering will be sent by #setBluetoothTethering.
+        if (type != TETHERING_BLUETOOTH) {
+            sendTetherResult(listener, result, type);
+        }
+    }
+
+    private void sendTetherResult(final IIntResultListener listener, final int result,
+            final int type) {
+        if (listener != null) {
+            try {
+                listener.onResult(result);
+            } catch (RemoteException e) { }
+        }
+
+        // If changing tethering fail, remove corresponding request
+        // no matter who trigger the start/stop.
+        if (result != TETHER_ERROR_NO_ERROR) mActiveTetheringRequests.remove(type);
+    }
+
+    private int setWifiTethering(final boolean enable) {
+        final long ident = Binder.clearCallingIdentity();
+        try {
+            synchronized (mPublicSync) {
+                final WifiManager mgr = getWifiManager();
+                if (mgr == null) {
+                    mLog.e("setWifiTethering: failed to get WifiManager!");
+                    return TETHER_ERROR_SERVICE_UNAVAIL;
+                }
+                if ((enable && mgr.startTetheredHotspot(null /* use existing softap config */))
+                        || (!enable && mgr.stopSoftAp())) {
+                    mWifiTetherRequested = enable;
+                    return TETHER_ERROR_NO_ERROR;
+                }
+            }
+        } finally {
+            Binder.restoreCallingIdentity(ident);
+        }
+
+        return TETHER_ERROR_INTERNAL_ERROR;
+    }
+
+    private void setBluetoothTethering(final boolean enable, final IIntResultListener listener) {
+        final BluetoothAdapter adapter = mDeps.getBluetoothAdapter();
+        if (adapter == null || !adapter.isEnabled()) {
+            Log.w(TAG, "Tried to enable bluetooth tethering with null or disabled adapter. null: "
+                    + (adapter == null));
+            sendTetherResult(listener, TETHER_ERROR_SERVICE_UNAVAIL, TETHERING_BLUETOOTH);
+            return;
+        }
+
+        adapter.getProfileProxy(mContext, new ServiceListener() {
+            @Override
+            public void onServiceDisconnected(int profile) { }
+
+            @Override
+            public void onServiceConnected(int profile, BluetoothProfile proxy) {
+                // Clear identify is fine because caller already pass tethering permission at
+                // ConnectivityService#startTethering()(or stopTethering) before the control comes
+                // here. Bluetooth will check tethering permission again that there is
+                // Context#getOpPackageName() under BluetoothPan#setBluetoothTethering() to get
+                // caller's package name for permission check.
+                // Calling BluetoothPan#setBluetoothTethering() here means the package name always
+                // be system server. If calling identity is not cleared, that package's uid might
+                // not match calling uid and end up in permission denied.
+                final long identityToken = Binder.clearCallingIdentity();
+                try {
+                    ((BluetoothPan) proxy).setBluetoothTethering(enable);
+                } finally {
+                    Binder.restoreCallingIdentity(identityToken);
+                }
+                // TODO: Enabling bluetooth tethering can fail asynchronously here.
+                // We should figure out a way to bubble up that failure instead of sending success.
+                final int result = (((BluetoothPan) proxy).isTetheringOn() == enable)
+                        ? TETHER_ERROR_NO_ERROR
+                        : TETHER_ERROR_INTERNAL_ERROR;
+                sendTetherResult(listener, result, TETHERING_BLUETOOTH);
+                adapter.closeProfileProxy(BluetoothProfile.PAN, proxy);
+            }
+        }, BluetoothProfile.PAN);
+    }
+
+    private int setEthernetTethering(final boolean enable) {
+        final EthernetManager em = (EthernetManager) mContext.getSystemService(
+                Context.ETHERNET_SERVICE);
+        synchronized (mPublicSync) {
+            if (enable) {
+                if (mEthernetCallback != null) {
+                    Log.d(TAG, "Ethernet tethering already started");
+                    return TETHER_ERROR_NO_ERROR;
+                }
+
+                mEthernetCallback = new EthernetCallback();
+                mEthernetIfaceRequest = em.requestTetheredInterface(mExecutor, mEthernetCallback);
+            } else {
+                stopEthernetTetheringLocked();
+            }
+        }
+        return TETHER_ERROR_NO_ERROR;
+    }
+
+    private void stopEthernetTetheringLocked() {
+        if (mConfiguredEthernetIface != null) {
+            stopTrackingInterfaceLocked(mConfiguredEthernetIface);
+            mConfiguredEthernetIface = null;
+        }
+        if (mEthernetCallback != null) {
+            mEthernetIfaceRequest.release();
+            mEthernetCallback = null;
+            mEthernetIfaceRequest = null;
+        }
+    }
+
+    private class EthernetCallback implements EthernetManager.TetheredInterfaceCallback {
+        @Override
+        public void onAvailable(String iface) {
+            synchronized (mPublicSync) {
+                if (this != mEthernetCallback) {
+                    // Ethernet callback arrived after Ethernet tethering stopped. Ignore.
+                    return;
+                }
+                maybeTrackNewInterfaceLocked(iface, TETHERING_ETHERNET);
+                changeInterfaceState(iface, IpServer.STATE_TETHERED);
+                mConfiguredEthernetIface = iface;
+            }
+        }
+
+        @Override
+        public void onUnavailable() {
+            synchronized (mPublicSync) {
+                if (this != mEthernetCallback) {
+                    // onAvailable called after stopping Ethernet tethering.
+                    return;
+                }
+                stopEthernetTetheringLocked();
+            }
+        }
+    }
+
+    int tether(String iface) {
+        return tether(iface, IpServer.STATE_TETHERED);
+    }
+
+    private int tether(String iface, int requestedState) {
+        if (DBG) Log.d(TAG, "Tethering " + iface);
+        synchronized (mPublicSync) {
+            TetherState tetherState = mTetherStates.get(iface);
+            if (tetherState == null) {
+                Log.e(TAG, "Tried to Tether an unknown iface: " + iface + ", ignoring");
+                return TETHER_ERROR_UNKNOWN_IFACE;
+            }
+            // Ignore the error status of the interface.  If the interface is available,
+            // the errors are referring to past tethering attempts anyway.
+            if (tetherState.lastState != IpServer.STATE_AVAILABLE) {
+                Log.e(TAG, "Tried to Tether an unavailable iface: " + iface + ", ignoring");
+                return TETHER_ERROR_UNAVAIL_IFACE;
+            }
+            // NOTE: If a CMD_TETHER_REQUESTED message is already in the TISM's queue but not yet
+            // processed, this will be a no-op and it will not return an error.
+            //
+            // This code cannot race with untether() because they both synchronize on mPublicSync.
+            // TODO: reexamine the threading and messaging model to totally remove mPublicSync.
+            final int type = tetherState.ipServer.interfaceType();
+            final TetheringRequestParcel request = mActiveTetheringRequests.get(type, null);
+            if (request != null) {
+                mActiveTetheringRequests.delete(type);
+            }
+            tetherState.ipServer.sendMessage(IpServer.CMD_TETHER_REQUESTED, requestedState, 0,
+                    request);
+            return TETHER_ERROR_NO_ERROR;
+        }
+    }
+
+    int untether(String iface) {
+        if (DBG) Log.d(TAG, "Untethering " + iface);
+        synchronized (mPublicSync) {
+            TetherState tetherState = mTetherStates.get(iface);
+            if (tetherState == null) {
+                Log.e(TAG, "Tried to Untether an unknown iface :" + iface + ", ignoring");
+                return TETHER_ERROR_UNKNOWN_IFACE;
+            }
+            if (!tetherState.isCurrentlyServing()) {
+                Log.e(TAG, "Tried to untether an inactive iface :" + iface + ", ignoring");
+                return TETHER_ERROR_UNAVAIL_IFACE;
+            }
+            tetherState.ipServer.sendMessage(IpServer.CMD_TETHER_UNREQUESTED);
+            return TETHER_ERROR_NO_ERROR;
+        }
+    }
+
+    void untetherAll() {
+        stopTethering(TETHERING_WIFI);
+        stopTethering(TETHERING_WIFI_P2P);
+        stopTethering(TETHERING_USB);
+        stopTethering(TETHERING_BLUETOOTH);
+        stopTethering(TETHERING_ETHERNET);
+    }
+
+    int getLastTetherError(String iface) {
+        synchronized (mPublicSync) {
+            TetherState tetherState = mTetherStates.get(iface);
+            if (tetherState == null) {
+                Log.e(TAG, "Tried to getLastTetherError on an unknown iface :" + iface
+                        + ", ignoring");
+                return TETHER_ERROR_UNKNOWN_IFACE;
+            }
+            return tetherState.lastError;
+        }
+    }
+
+    private boolean isProvisioningNeededButUnavailable() {
+        return isTetherProvisioningRequired() && !doesEntitlementPackageExist();
+    }
+
+    boolean isTetherProvisioningRequired() {
+        final TetheringConfiguration cfg = mConfig;
+        return mEntitlementMgr.isTetherProvisioningRequired(cfg);
+    }
+
+    private boolean doesEntitlementPackageExist() {
+        // provisioningApp must contain package and class name.
+        if (mConfig.provisioningApp.length != 2) {
+            return false;
+        }
+
+        final PackageManager pm = mContext.getPackageManager();
+        try {
+            pm.getPackageInfo(mConfig.provisioningApp[0], GET_ACTIVITIES);
+        } catch (PackageManager.NameNotFoundException e) {
+            return false;
+        }
+        return true;
+    }
+
+    // TODO: Figure out how to update for local hotspot mode interfaces.
+    private void sendTetherStateChangedBroadcast() {
+        if (!isTetheringSupported()) return;
+
+        final ArrayList<String> availableList = new ArrayList<>();
+        final ArrayList<String> tetherList = new ArrayList<>();
+        final ArrayList<String> localOnlyList = new ArrayList<>();
+        final ArrayList<String> erroredList = new ArrayList<>();
+        final ArrayList<Integer> lastErrorList = new ArrayList<>();
+
+        final TetheringConfiguration cfg = mConfig;
+        mTetherStatesParcel = new TetherStatesParcel();
+
+        int downstreamTypesMask = DOWNSTREAM_NONE;
+        synchronized (mPublicSync) {
+            for (int i = 0; i < mTetherStates.size(); i++) {
+                TetherState tetherState = mTetherStates.valueAt(i);
+                String iface = mTetherStates.keyAt(i);
+                if (tetherState.lastError != TETHER_ERROR_NO_ERROR) {
+                    erroredList.add(iface);
+                    lastErrorList.add(tetherState.lastError);
+                } else if (tetherState.lastState == IpServer.STATE_AVAILABLE) {
+                    availableList.add(iface);
+                } else if (tetherState.lastState == IpServer.STATE_LOCAL_ONLY) {
+                    localOnlyList.add(iface);
+                } else if (tetherState.lastState == IpServer.STATE_TETHERED) {
+                    if (cfg.isUsb(iface)) {
+                        downstreamTypesMask |= (1 << TETHERING_USB);
+                    } else if (cfg.isWifi(iface)) {
+                        downstreamTypesMask |= (1 << TETHERING_WIFI);
+                    } else if (cfg.isBluetooth(iface)) {
+                        downstreamTypesMask |= (1 << TETHERING_BLUETOOTH);
+                    }
+                    tetherList.add(iface);
+                }
+            }
+        }
+
+        mTetherStatesParcel.availableList = availableList.toArray(new String[0]);
+        mTetherStatesParcel.tetheredList = tetherList.toArray(new String[0]);
+        mTetherStatesParcel.localOnlyList = localOnlyList.toArray(new String[0]);
+        mTetherStatesParcel.erroredIfaceList = erroredList.toArray(new String[0]);
+        mTetherStatesParcel.lastErrorList = new int[lastErrorList.size()];
+        Iterator<Integer> iterator = lastErrorList.iterator();
+        for (int i = 0; i < lastErrorList.size(); i++) {
+            mTetherStatesParcel.lastErrorList[i] = iterator.next().intValue();
+        }
+        reportTetherStateChanged(mTetherStatesParcel);
+
+        final Intent bcast = new Intent(ACTION_TETHER_STATE_CHANGED);
+        bcast.addFlags(Intent.FLAG_RECEIVER_REPLACE_PENDING);
+        bcast.putStringArrayListExtra(EXTRA_AVAILABLE_TETHER, availableList);
+        bcast.putStringArrayListExtra(EXTRA_ACTIVE_LOCAL_ONLY, localOnlyList);
+        bcast.putStringArrayListExtra(EXTRA_ACTIVE_TETHER, tetherList);
+        bcast.putStringArrayListExtra(EXTRA_ERRORED_TETHER, erroredList);
+        mContext.sendStickyBroadcastAsUser(bcast, UserHandle.ALL);
+        if (DBG) {
+            Log.d(TAG, String.format(
+                    "sendTetherStateChangedBroadcast %s=[%s] %s=[%s] %s=[%s] %s=[%s]",
+                    "avail", TextUtils.join(",", availableList),
+                    "local_only", TextUtils.join(",", localOnlyList),
+                    "tether", TextUtils.join(",", tetherList),
+                    "error", TextUtils.join(",", erroredList)));
+        }
+
+        mNotificationUpdater.onDownstreamChanged(downstreamTypesMask);
+    }
+
+    private class StateReceiver extends BroadcastReceiver {
+        @Override
+        public void onReceive(Context content, Intent intent) {
+            final String action = intent.getAction();
+            if (action == null) return;
+
+            if (action.equals(UsbManager.ACTION_USB_STATE)) {
+                handleUsbAction(intent);
+            } else if (action.equals(CONNECTIVITY_ACTION)) {
+                handleConnectivityAction(intent);
+            } else if (action.equals(WifiManager.WIFI_AP_STATE_CHANGED_ACTION)) {
+                handleWifiApAction(intent);
+            } else if (action.equals(WifiP2pManager.WIFI_P2P_CONNECTION_CHANGED_ACTION)) {
+                handleWifiP2pAction(intent);
+            } else if (action.equals(Intent.ACTION_CONFIGURATION_CHANGED)) {
+                mLog.log("OBSERVED configuration changed");
+                updateConfiguration();
+            } else if (action.equals(UserManager.ACTION_USER_RESTRICTIONS_CHANGED)) {
+                mLog.log("OBSERVED user restrictions changed");
+                handleUserRestrictionAction();
+            } else if (action.equals(ACTION_RESTRICT_BACKGROUND_CHANGED)) {
+                mLog.log("OBSERVED data saver changed");
+                handleDataSaverChanged();
+            } else if (action.equals(TetheringNotificationUpdater.ACTION_DISABLE_TETHERING)) {
+                untetherAll();
+            }
+        }
+
+        private void handleConnectivityAction(Intent intent) {
+            final NetworkInfo networkInfo =
+                    (NetworkInfo) intent.getParcelableExtra(EXTRA_NETWORK_INFO);
+            if (networkInfo == null
+                    || networkInfo.getDetailedState() == NetworkInfo.DetailedState.FAILED) {
+                return;
+            }
+
+            if (VDBG) Log.d(TAG, "Tethering got CONNECTIVITY_ACTION: " + networkInfo.toString());
+            mTetherMainSM.sendMessage(TetherMainSM.CMD_UPSTREAM_CHANGED);
+        }
+
+        private void handleUsbAction(Intent intent) {
+            final boolean usbConnected = intent.getBooleanExtra(USB_CONNECTED, false);
+            final boolean usbConfigured = intent.getBooleanExtra(USB_CONFIGURED, false);
+            final boolean rndisEnabled = intent.getBooleanExtra(USB_FUNCTION_RNDIS, false);
+            final boolean ncmEnabled = intent.getBooleanExtra(USB_FUNCTION_NCM, false);
+
+            mLog.log(String.format("USB bcast connected:%s configured:%s rndis:%s",
+                    usbConnected, usbConfigured, rndisEnabled));
+
+            // There are three types of ACTION_USB_STATE:
+            //
+            //     - DISCONNECTED (USB_CONNECTED and USB_CONFIGURED are 0)
+            //       Meaning: USB connection has ended either because of
+            //       software reset or hard unplug.
+            //
+            //     - CONNECTED (USB_CONNECTED is 1, USB_CONFIGURED is 0)
+            //       Meaning: the first stage of USB protocol handshake has
+            //       occurred but it is not complete.
+            //
+            //     - CONFIGURED (USB_CONNECTED and USB_CONFIGURED are 1)
+            //       Meaning: the USB handshake is completely done and all the
+            //       functions are ready to use.
+            //
+            // For more explanation, see b/62552150 .
+            synchronized (Tethering.this.mPublicSync) {
+                if (!usbConnected && mRndisEnabled) {
+                    // Turn off tethering if it was enabled and there is a disconnect.
+                    tetherMatchingInterfaces(IpServer.STATE_AVAILABLE, TETHERING_USB);
+                    mEntitlementMgr.stopProvisioningIfNeeded(TETHERING_USB);
+                } else if (usbConfigured && rndisEnabled) {
+                    // Tether if rndis is enabled and usb is configured.
+                    tetherMatchingInterfaces(IpServer.STATE_TETHERED, TETHERING_USB);
+                } else if (usbConnected && ncmEnabled) {
+                    tetherMatchingInterfaces(IpServer.STATE_LOCAL_ONLY, TETHERING_NCM);
+                }
+                mRndisEnabled = usbConfigured && rndisEnabled;
+            }
+        }
+
+        private void handleWifiApAction(Intent intent) {
+            final int curState = intent.getIntExtra(EXTRA_WIFI_AP_STATE, WIFI_AP_STATE_DISABLED);
+            final String ifname = intent.getStringExtra(EXTRA_WIFI_AP_INTERFACE_NAME);
+            final int ipmode = intent.getIntExtra(EXTRA_WIFI_AP_MODE, IFACE_IP_MODE_UNSPECIFIED);
+
+            synchronized (Tethering.this.mPublicSync) {
+                switch (curState) {
+                    case WifiManager.WIFI_AP_STATE_ENABLING:
+                        // We can see this state on the way to both enabled and failure states.
+                        break;
+                    case WifiManager.WIFI_AP_STATE_ENABLED:
+                        enableWifiIpServingLocked(ifname, ipmode);
+                        break;
+                    case WifiManager.WIFI_AP_STATE_DISABLING:
+                        // We can see this state on the way to disabled.
+                        break;
+                    case WifiManager.WIFI_AP_STATE_DISABLED:
+                    case WifiManager.WIFI_AP_STATE_FAILED:
+                    default:
+                        disableWifiIpServingLocked(ifname, curState);
+                        break;
+                }
+            }
+        }
+
+        private boolean isGroupOwner(WifiP2pGroup group) {
+            return group != null && group.isGroupOwner()
+                    && !TextUtils.isEmpty(group.getInterface());
+        }
+
+        private void handleWifiP2pAction(Intent intent) {
+            if (mConfig.isWifiP2pLegacyTetheringMode()) return;
+
+            final WifiP2pInfo p2pInfo =
+                    (WifiP2pInfo) intent.getParcelableExtra(WifiP2pManager.EXTRA_WIFI_P2P_INFO);
+            final WifiP2pGroup group =
+                    (WifiP2pGroup) intent.getParcelableExtra(WifiP2pManager.EXTRA_WIFI_P2P_GROUP);
+
+            if (VDBG) {
+                Log.d(TAG, "WifiP2pAction: P2pInfo: " + p2pInfo + " Group: " + group);
+            }
+
+            synchronized (Tethering.this.mPublicSync) {
+                // if no group is formed, bring it down if needed.
+                if (p2pInfo == null || !p2pInfo.groupFormed) {
+                    disableWifiP2pIpServingLockedIfNeeded(mWifiP2pTetherInterface);
+                    mWifiP2pTetherInterface = null;
+                    return;
+                }
+
+                // If there is a group but the device is not the owner, bail out.
+                if (!isGroupOwner(group)) return;
+
+                // If already serving from the correct interface, nothing to do.
+                if (group.getInterface().equals(mWifiP2pTetherInterface)) return;
+
+                // If already serving from another interface, turn it down first.
+                if (!TextUtils.isEmpty(mWifiP2pTetherInterface)) {
+                    mLog.w("P2P tethered interface " + mWifiP2pTetherInterface
+                            + "is different from current interface "
+                            + group.getInterface() + ", re-tether it");
+                    disableWifiP2pIpServingLockedIfNeeded(mWifiP2pTetherInterface);
+                }
+
+                // Finally bring up serving on the new interface
+                mWifiP2pTetherInterface = group.getInterface();
+                enableWifiIpServingLocked(mWifiP2pTetherInterface, IFACE_IP_MODE_LOCAL_ONLY);
+            }
+        }
+
+        private void handleUserRestrictionAction() {
+            mTetheringRestriction.onUserRestrictionsChanged();
+        }
+
+        private void handleDataSaverChanged() {
+            final ConnectivityManager connMgr = (ConnectivityManager) mContext.getSystemService(
+                    Context.CONNECTIVITY_SERVICE);
+            final boolean isDataSaverEnabled = connMgr.getRestrictBackgroundStatus()
+                    != ConnectivityManager.RESTRICT_BACKGROUND_STATUS_DISABLED;
+
+            if (mDataSaverEnabled == isDataSaverEnabled) return;
+
+            mDataSaverEnabled = isDataSaverEnabled;
+            if (mDataSaverEnabled) {
+                untetherAll();
+            }
+        }
+    }
+
+    @VisibleForTesting
+    boolean isTetheringActive() {
+        return mActiveTetheringRequests.size() > 0;
+    }
+
+    @VisibleForTesting
+    protected static class UserRestrictionActionListener {
+        private final UserManager mUserMgr;
+        private final Tethering mWrapper;
+        private final TetheringNotificationUpdater mNotificationUpdater;
+        public boolean mDisallowTethering;
+
+        public UserRestrictionActionListener(@NonNull UserManager um, @NonNull Tethering wrapper,
+                @NonNull TetheringNotificationUpdater updater) {
+            mUserMgr = um;
+            mWrapper = wrapper;
+            mNotificationUpdater = updater;
+            mDisallowTethering = false;
+        }
+
+        public void onUserRestrictionsChanged() {
+            // getUserRestrictions gets restriction for this process' user, which is the primary
+            // user. This is fine because DISALLOW_CONFIG_TETHERING can only be set on the primary
+            // user. See UserManager.DISALLOW_CONFIG_TETHERING.
+            final Bundle restrictions = mUserMgr.getUserRestrictions();
+            final boolean newlyDisallowed =
+                    restrictions.getBoolean(UserManager.DISALLOW_CONFIG_TETHERING);
+            final boolean prevDisallowed = mDisallowTethering;
+            mDisallowTethering = newlyDisallowed;
+
+            final boolean tetheringDisallowedChanged = (newlyDisallowed != prevDisallowed);
+            if (!tetheringDisallowedChanged) {
+                return;
+            }
+
+            if (!newlyDisallowed) {
+                // Clear the restricted notification when user is allowed to have tethering
+                // function.
+                mNotificationUpdater.tetheringRestrictionLifted();
+                return;
+            }
+
+            if (mWrapper.isTetheringActive()) {
+                // Restricted notification is shown when tethering function is disallowed on
+                // user's device.
+                mNotificationUpdater.notifyTetheringDisabledByRestriction();
+
+                // Untether from all downstreams since tethering is disallowed.
+                mWrapper.untetherAll();
+            }
+            // TODO(b/148139325): send tetheringSupported on restriction change
+        }
+    }
+
+    private void disableWifiIpServingLockedCommon(int tetheringType, String ifname, int apState) {
+        mLog.log("Canceling WiFi tethering request -"
+                + " type=" + tetheringType
+                + " interface=" + ifname
+                + " state=" + apState);
+
+        if (!TextUtils.isEmpty(ifname)) {
+            final TetherState ts = mTetherStates.get(ifname);
+            if (ts != null) {
+                ts.ipServer.unwanted();
+                return;
+            }
+        }
+
+        for (int i = 0; i < mTetherStates.size(); i++) {
+            final IpServer ipServer = mTetherStates.valueAt(i).ipServer;
+            if (ipServer.interfaceType() == tetheringType) {
+                ipServer.unwanted();
+                return;
+            }
+        }
+
+        mLog.log("Error disabling Wi-Fi IP serving; "
+                + (TextUtils.isEmpty(ifname) ? "no interface name specified"
+                                           : "specified interface: " + ifname));
+    }
+
+    private void disableWifiIpServingLocked(String ifname, int apState) {
+        // Regardless of whether we requested this transition, the AP has gone
+        // down.  Don't try to tether again unless we're requested to do so.
+        // TODO: Remove this altogether, once Wi-Fi reliably gives us an
+        // interface name with every broadcast.
+        mWifiTetherRequested = false;
+
+        disableWifiIpServingLockedCommon(TETHERING_WIFI, ifname, apState);
+    }
+
+    private void disableWifiP2pIpServingLockedIfNeeded(String ifname) {
+        if (TextUtils.isEmpty(ifname)) return;
+
+        disableWifiIpServingLockedCommon(TETHERING_WIFI_P2P, ifname, /* fake */ 0);
+    }
+
+    private void enableWifiIpServingLocked(String ifname, int wifiIpMode) {
+        // Map wifiIpMode values to IpServer.Callback serving states, inferring
+        // from mWifiTetherRequested as a final "best guess".
+        final int ipServingMode;
+        switch (wifiIpMode) {
+            case IFACE_IP_MODE_TETHERED:
+                ipServingMode = IpServer.STATE_TETHERED;
+                break;
+            case IFACE_IP_MODE_LOCAL_ONLY:
+                ipServingMode = IpServer.STATE_LOCAL_ONLY;
+                break;
+            default:
+                mLog.e("Cannot enable IP serving in unknown WiFi mode: " + wifiIpMode);
+                return;
+        }
+
+        if (!TextUtils.isEmpty(ifname)) {
+            maybeTrackNewInterfaceLocked(ifname);
+            changeInterfaceState(ifname, ipServingMode);
+        } else {
+            mLog.e(String.format(
+                    "Cannot enable IP serving in mode %s on missing interface name",
+                    ipServingMode));
+        }
+    }
+
+    // TODO: Consider renaming to something more accurate in its description.
+    // This method:
+    //     - allows requesting either tethering or local hotspot serving states
+    //     - handles both enabling and disabling serving states
+    //     - only tethers the first matching interface in listInterfaces()
+    //       order of a given type
+    private void tetherMatchingInterfaces(int requestedState, int interfaceType) {
+        if (VDBG) {
+            Log.d(TAG, "tetherMatchingInterfaces(" + requestedState + ", " + interfaceType + ")");
+        }
+
+        String[] ifaces = null;
+        try {
+            ifaces = mNetd.interfaceGetList();
+        } catch (RemoteException | ServiceSpecificException e) {
+            Log.e(TAG, "Error listing Interfaces", e);
+            return;
+        }
+        String chosenIface = null;
+        if (ifaces != null) {
+            for (String iface : ifaces) {
+                if (ifaceNameToType(iface) == interfaceType) {
+                    chosenIface = iface;
+                    break;
+                }
+            }
+        }
+        if (chosenIface == null) {
+            Log.e(TAG, "could not find iface of type " + interfaceType);
+            return;
+        }
+
+        changeInterfaceState(chosenIface, requestedState);
+    }
+
+    private void changeInterfaceState(String ifname, int requestedState) {
+        final int result;
+        switch (requestedState) {
+            case IpServer.STATE_UNAVAILABLE:
+            case IpServer.STATE_AVAILABLE:
+                result = untether(ifname);
+                break;
+            case IpServer.STATE_TETHERED:
+            case IpServer.STATE_LOCAL_ONLY:
+                result = tether(ifname, requestedState);
+                break;
+            default:
+                Log.wtf(TAG, "Unknown interface state: " + requestedState);
+                return;
+        }
+        if (result != TETHER_ERROR_NO_ERROR) {
+            Log.e(TAG, "unable start or stop tethering on iface " + ifname);
+            return;
+        }
+    }
+
+    TetheringConfiguration getTetheringConfiguration() {
+        return mConfig;
+    }
+
+    boolean hasTetherableConfiguration() {
+        final TetheringConfiguration cfg = mConfig;
+        final boolean hasDownstreamConfiguration =
+                (cfg.tetherableUsbRegexs.length != 0)
+                || (cfg.tetherableWifiRegexs.length != 0)
+                || (cfg.tetherableBluetoothRegexs.length != 0);
+        final boolean hasUpstreamConfiguration = !cfg.preferredUpstreamIfaceTypes.isEmpty()
+                || cfg.chooseUpstreamAutomatically;
+
+        return hasDownstreamConfiguration && hasUpstreamConfiguration;
+    }
+
+    // TODO - update callers to use getTetheringConfiguration(),
+    // which has only final members.
+    String[] getTetherableUsbRegexs() {
+        return copy(mConfig.tetherableUsbRegexs);
+    }
+
+    String[] getTetherableWifiRegexs() {
+        return copy(mConfig.tetherableWifiRegexs);
+    }
+
+    String[] getTetherableBluetoothRegexs() {
+        return copy(mConfig.tetherableBluetoothRegexs);
+    }
+
+    int setUsbTethering(boolean enable) {
+        if (VDBG) Log.d(TAG, "setUsbTethering(" + enable + ")");
+        UsbManager usbManager = (UsbManager) mContext.getSystemService(Context.USB_SERVICE);
+        if (usbManager == null) {
+            mLog.e("setUsbTethering: failed to get UsbManager!");
+            return TETHER_ERROR_SERVICE_UNAVAIL;
+        }
+
+        synchronized (mPublicSync) {
+            usbManager.setCurrentFunctions(enable ? UsbManager.FUNCTION_RNDIS
+                    : UsbManager.FUNCTION_NONE);
+        }
+        return TETHER_ERROR_NO_ERROR;
+    }
+
+    private int setNcmTethering(boolean enable) {
+        if (VDBG) Log.d(TAG, "setNcmTethering(" + enable + ")");
+        UsbManager usbManager = (UsbManager) mContext.getSystemService(Context.USB_SERVICE);
+        synchronized (mPublicSync) {
+            usbManager.setCurrentFunctions(enable ? UsbManager.FUNCTION_NCM
+                    : UsbManager.FUNCTION_NONE);
+        }
+        return TETHER_ERROR_NO_ERROR;
+    }
+
+    // TODO review API - figure out how to delete these entirely.
+    String[] getTetheredIfaces() {
+        ArrayList<String> list = new ArrayList<String>();
+        synchronized (mPublicSync) {
+            for (int i = 0; i < mTetherStates.size(); i++) {
+                TetherState tetherState = mTetherStates.valueAt(i);
+                if (tetherState.lastState == IpServer.STATE_TETHERED) {
+                    list.add(mTetherStates.keyAt(i));
+                }
+            }
+        }
+        return list.toArray(new String[list.size()]);
+    }
+
+    String[] getTetherableIfaces() {
+        ArrayList<String> list = new ArrayList<String>();
+        synchronized (mPublicSync) {
+            for (int i = 0; i < mTetherStates.size(); i++) {
+                TetherState tetherState = mTetherStates.valueAt(i);
+                if (tetherState.lastState == IpServer.STATE_AVAILABLE) {
+                    list.add(mTetherStates.keyAt(i));
+                }
+            }
+        }
+        return list.toArray(new String[list.size()]);
+    }
+
+    String[] getTetheredDhcpRanges() {
+        // TODO: this is only valid for the old DHCP server. Latest search suggests it is only used
+        // by WifiP2pServiceImpl to start dnsmasq: remove/deprecate after migrating callers.
+        return mConfig.legacyDhcpRanges;
+    }
+
+    String[] getErroredIfaces() {
+        ArrayList<String> list = new ArrayList<String>();
+        synchronized (mPublicSync) {
+            for (int i = 0; i < mTetherStates.size(); i++) {
+                TetherState tetherState = mTetherStates.valueAt(i);
+                if (tetherState.lastError != TETHER_ERROR_NO_ERROR) {
+                    list.add(mTetherStates.keyAt(i));
+                }
+            }
+        }
+        return list.toArray(new String[list.size()]);
+    }
+
+    private void logMessage(State state, int what) {
+        mLog.log(state.getName() + " got " + sMagicDecoderRing.get(what, Integer.toString(what)));
+    }
+
+    private boolean upstreamWanted() {
+        if (!mForwardedDownstreams.isEmpty()) return true;
+
+        synchronized (mPublicSync) {
+            return mWifiTetherRequested;
+        }
+    }
+
+    // Needed because the canonical source of upstream truth is just the
+    // upstream interface set, |mCurrentUpstreamIfaceSet|.
+    private boolean pertainsToCurrentUpstream(UpstreamNetworkState ns) {
+        if (ns != null && ns.linkProperties != null && mCurrentUpstreamIfaceSet != null) {
+            for (String ifname : ns.linkProperties.getAllInterfaceNames()) {
+                if (mCurrentUpstreamIfaceSet.ifnames.contains(ifname)) {
+                    return true;
+                }
+            }
+        }
+        return false;
+    }
+
+    class TetherMainSM extends StateMachine {
+        // an interface SM has requested Tethering/Local Hotspot
+        static final int EVENT_IFACE_SERVING_STATE_ACTIVE       = BASE_MAIN_SM + 1;
+        // an interface SM has unrequested Tethering/Local Hotspot
+        static final int EVENT_IFACE_SERVING_STATE_INACTIVE     = BASE_MAIN_SM + 2;
+        // upstream connection change - do the right thing
+        static final int CMD_UPSTREAM_CHANGED                   = BASE_MAIN_SM + 3;
+        // we don't have a valid upstream conn, check again after a delay
+        static final int CMD_RETRY_UPSTREAM                     = BASE_MAIN_SM + 4;
+        // Events from NetworkCallbacks that we process on the main state
+        // machine thread on behalf of the UpstreamNetworkMonitor.
+        static final int EVENT_UPSTREAM_CALLBACK                = BASE_MAIN_SM + 5;
+        // we treated the error and want now to clear it
+        static final int CMD_CLEAR_ERROR                        = BASE_MAIN_SM + 6;
+        static final int EVENT_IFACE_UPDATE_LINKPROPERTIES      = BASE_MAIN_SM + 7;
+        // Events from EntitlementManager to choose upstream again.
+        static final int EVENT_UPSTREAM_PERMISSION_CHANGED      = BASE_MAIN_SM + 8;
+        private final State mInitialState;
+        private final State mTetherModeAliveState;
+
+        private final State mSetIpForwardingEnabledErrorState;
+        private final State mSetIpForwardingDisabledErrorState;
+        private final State mStartTetheringErrorState;
+        private final State mStopTetheringErrorState;
+        private final State mSetDnsForwardersErrorState;
+
+        // This list is a little subtle.  It contains all the interfaces that currently are
+        // requesting tethering, regardless of whether these interfaces are still members of
+        // mTetherStates.  This allows us to maintain the following predicates:
+        //
+        // 1) mTetherStates contains the set of all currently existing, tetherable, link state up
+        //    interfaces.
+        // 2) mNotifyList contains all state machines that may have outstanding tethering state
+        //    that needs to be torn down.
+        //
+        // Because we excise interfaces immediately from mTetherStates, we must maintain mNotifyList
+        // so that the garbage collector does not clean up the state machine before it has a chance
+        // to tear itself down.
+        private final ArrayList<IpServer> mNotifyList;
+        private final IPv6TetheringCoordinator mIPv6TetheringCoordinator;
+        private final OffloadWrapper mOffload;
+
+        private static final int UPSTREAM_SETTLE_TIME_MS     = 10000;
+
+        TetherMainSM(String name, Looper looper, TetheringDependencies deps) {
+            super(name, looper);
+
+            mInitialState = new InitialState();
+            mTetherModeAliveState = new TetherModeAliveState();
+            mSetIpForwardingEnabledErrorState = new SetIpForwardingEnabledErrorState();
+            mSetIpForwardingDisabledErrorState = new SetIpForwardingDisabledErrorState();
+            mStartTetheringErrorState = new StartTetheringErrorState();
+            mStopTetheringErrorState = new StopTetheringErrorState();
+            mSetDnsForwardersErrorState = new SetDnsForwardersErrorState();
+
+            addState(mInitialState);
+            addState(mTetherModeAliveState);
+            addState(mSetIpForwardingEnabledErrorState);
+            addState(mSetIpForwardingDisabledErrorState);
+            addState(mStartTetheringErrorState);
+            addState(mStopTetheringErrorState);
+            addState(mSetDnsForwardersErrorState);
+
+            mNotifyList = new ArrayList<>();
+            mIPv6TetheringCoordinator = deps.getIPv6TetheringCoordinator(mNotifyList, mLog);
+            mOffload = new OffloadWrapper();
+
+            setInitialState(mInitialState);
+        }
+
+        class InitialState extends State {
+            @Override
+            public boolean processMessage(Message message) {
+                logMessage(this, message.what);
+                switch (message.what) {
+                    case EVENT_IFACE_SERVING_STATE_ACTIVE: {
+                        final IpServer who = (IpServer) message.obj;
+                        if (VDBG) Log.d(TAG, "Tether Mode requested by " + who);
+                        handleInterfaceServingStateActive(message.arg1, who);
+                        transitionTo(mTetherModeAliveState);
+                        break;
+                    }
+                    case EVENT_IFACE_SERVING_STATE_INACTIVE: {
+                        final IpServer who = (IpServer) message.obj;
+                        if (VDBG) Log.d(TAG, "Tether Mode unrequested by " + who);
+                        handleInterfaceServingStateInactive(who);
+                        break;
+                    }
+                    case EVENT_IFACE_UPDATE_LINKPROPERTIES:
+                        // Silently ignore these for now.
+                        break;
+                    default:
+                        return NOT_HANDLED;
+                }
+                return HANDLED;
+            }
+        }
+
+        protected boolean turnOnMainTetherSettings() {
+            final TetheringConfiguration cfg = mConfig;
+            try {
+                mNetd.ipfwdEnableForwarding(TAG);
+            } catch (RemoteException | ServiceSpecificException e) {
+                mLog.e(e);
+                transitionTo(mSetIpForwardingEnabledErrorState);
+                return false;
+            }
+
+            // TODO: Randomize DHCPv4 ranges, especially in hotspot mode.
+            // Legacy DHCP server is disabled if passed an empty ranges array
+            final String[] dhcpRanges = cfg.enableLegacyDhcpServer
+                    ? cfg.legacyDhcpRanges : new String[0];
+            try {
+                NetdUtils.tetherStart(mNetd, true /** usingLegacyDnsProxy */, dhcpRanges);
+            } catch (RemoteException | ServiceSpecificException e) {
+                try {
+                    // Stop and retry.
+                    mNetd.tetherStop();
+                    NetdUtils.tetherStart(mNetd, true /** usingLegacyDnsProxy */, dhcpRanges);
+                } catch (RemoteException | ServiceSpecificException ee) {
+                    mLog.e(ee);
+                    transitionTo(mStartTetheringErrorState);
+                    return false;
+                }
+            }
+            mLog.log("SET main tether settings: ON");
+            return true;
+        }
+
+        protected boolean turnOffMainTetherSettings() {
+            try {
+                mNetd.tetherStop();
+            } catch (RemoteException | ServiceSpecificException e) {
+                mLog.e(e);
+                transitionTo(mStopTetheringErrorState);
+                return false;
+            }
+            try {
+                mNetd.ipfwdDisableForwarding(TAG);
+            } catch (RemoteException | ServiceSpecificException e) {
+                mLog.e(e);
+                transitionTo(mSetIpForwardingDisabledErrorState);
+                return false;
+            }
+            transitionTo(mInitialState);
+            mLog.log("SET main tether settings: OFF");
+            return true;
+        }
+
+        protected void chooseUpstreamType(boolean tryCell) {
+            // We rebuild configuration on ACTION_CONFIGURATION_CHANGED, but we
+            // do not currently know how to watch for changes in DUN settings.
+            maybeDunSettingChanged();
+
+            final TetheringConfiguration config = mConfig;
+            final UpstreamNetworkState ns = (config.chooseUpstreamAutomatically)
+                    ? mUpstreamNetworkMonitor.getCurrentPreferredUpstream()
+                    : mUpstreamNetworkMonitor.selectPreferredUpstreamType(
+                            config.preferredUpstreamIfaceTypes);
+            if (ns == null) {
+                if (tryCell) {
+                    mUpstreamNetworkMonitor.registerMobileNetworkRequest();
+                    // We think mobile should be coming up; don't set a retry.
+                } else {
+                    sendMessageDelayed(CMD_RETRY_UPSTREAM, UPSTREAM_SETTLE_TIME_MS);
+                }
+            }
+            setUpstreamNetwork(ns);
+            final Network newUpstream = (ns != null) ? ns.network : null;
+            if (mTetherUpstream != newUpstream) {
+                mTetherUpstream = newUpstream;
+                mUpstreamNetworkMonitor.setCurrentUpstream(mTetherUpstream);
+                reportUpstreamChanged(ns);
+            }
+        }
+
+        protected void setUpstreamNetwork(UpstreamNetworkState ns) {
+            InterfaceSet ifaces = null;
+            if (ns != null) {
+                // Find the interface with the default IPv4 route. It may be the
+                // interface described by linkProperties, or one of the interfaces
+                // stacked on top of it.
+                mLog.i("Looking for default routes on: " + ns.linkProperties);
+                ifaces = TetheringInterfaceUtils.getTetheringInterfaces(ns);
+                mLog.i("Found upstream interface(s): " + ifaces);
+            }
+
+            if (ifaces != null) {
+                setDnsForwarders(ns.network, ns.linkProperties);
+            }
+            notifyDownstreamsOfNewUpstreamIface(ifaces);
+            if (ns != null && pertainsToCurrentUpstream(ns)) {
+                // If we already have UpstreamNetworkState for this network update it immediately.
+                handleNewUpstreamNetworkState(ns);
+            } else if (mCurrentUpstreamIfaceSet == null) {
+                // There are no available upstream networks.
+                handleNewUpstreamNetworkState(null);
+            }
+        }
+
+        protected void setDnsForwarders(final Network network, final LinkProperties lp) {
+            // TODO: Set v4 and/or v6 DNS per available connectivity.
+            final Collection<InetAddress> dnses = lp.getDnsServers();
+            // TODO: Properly support the absence of DNS servers.
+            final String[] dnsServers;
+            if (dnses != null && !dnses.isEmpty()) {
+                dnsServers = new String[dnses.size()];
+                int i = 0;
+                for (InetAddress dns : dnses) {
+                    dnsServers[i++] = dns.getHostAddress();
+                }
+            } else {
+                dnsServers = mConfig.defaultIPv4DNS;
+            }
+            final int netId = (network != null) ? network.getNetId() : NETID_UNSET;
+            try {
+                mNetd.tetherDnsSet(netId, dnsServers);
+                mLog.log(String.format(
+                        "SET DNS forwarders: network=%s dnsServers=%s",
+                        network, Arrays.toString(dnsServers)));
+            } catch (RemoteException | ServiceSpecificException e) {
+                // TODO: Investigate how this can fail and what exactly
+                // happens if/when such failures occur.
+                mLog.e("setting DNS forwarders failed, " + e);
+                transitionTo(mSetDnsForwardersErrorState);
+            }
+        }
+
+        protected void notifyDownstreamsOfNewUpstreamIface(InterfaceSet ifaces) {
+            mCurrentUpstreamIfaceSet = ifaces;
+            for (IpServer ipServer : mNotifyList) {
+                ipServer.sendMessage(IpServer.CMD_TETHER_CONNECTION_CHANGED, ifaces);
+            }
+        }
+
+        protected void handleNewUpstreamNetworkState(UpstreamNetworkState ns) {
+            mIPv6TetheringCoordinator.updateUpstreamNetworkState(ns);
+            mOffload.updateUpstreamNetworkState(ns);
+        }
+
+        private void handleInterfaceServingStateActive(int mode, IpServer who) {
+            if (mNotifyList.indexOf(who) < 0) {
+                mNotifyList.add(who);
+                mIPv6TetheringCoordinator.addActiveDownstream(who, mode);
+            }
+
+            if (mode == IpServer.STATE_TETHERED) {
+                // No need to notify OffloadController just yet as there are no
+                // "offload-able" prefixes to pass along. This will handled
+                // when the TISM informs Tethering of its LinkProperties.
+                mForwardedDownstreams.add(who);
+            } else {
+                mOffload.excludeDownstreamInterface(who.interfaceName());
+                mForwardedDownstreams.remove(who);
+            }
+
+            // If this is a Wi-Fi interface, notify WifiManager of the active serving state.
+            if (who.interfaceType() == TETHERING_WIFI) {
+                final WifiManager mgr = getWifiManager();
+                final String iface = who.interfaceName();
+                switch (mode) {
+                    case IpServer.STATE_TETHERED:
+                        mgr.updateInterfaceIpState(iface, IFACE_IP_MODE_TETHERED);
+                        break;
+                    case IpServer.STATE_LOCAL_ONLY:
+                        mgr.updateInterfaceIpState(iface, IFACE_IP_MODE_LOCAL_ONLY);
+                        break;
+                    default:
+                        Log.wtf(TAG, "Unknown active serving mode: " + mode);
+                        break;
+                }
+            }
+        }
+
+        private void handleInterfaceServingStateInactive(IpServer who) {
+            mNotifyList.remove(who);
+            mIPv6TetheringCoordinator.removeActiveDownstream(who);
+            mOffload.excludeDownstreamInterface(who.interfaceName());
+            mForwardedDownstreams.remove(who);
+            updateConnectedClients(null /* wifiClients */);
+
+            // If this is a Wi-Fi interface, tell WifiManager of any errors
+            // or the inactive serving state.
+            if (who.interfaceType() == TETHERING_WIFI) {
+                if (who.lastError() != TETHER_ERROR_NO_ERROR) {
+                    getWifiManager().updateInterfaceIpState(
+                            who.interfaceName(), IFACE_IP_MODE_CONFIGURATION_ERROR);
+                } else {
+                    getWifiManager().updateInterfaceIpState(
+                            who.interfaceName(), IFACE_IP_MODE_UNSPECIFIED);
+                }
+            }
+        }
+
+        @VisibleForTesting
+        void handleUpstreamNetworkMonitorCallback(int arg1, Object o) {
+            if (arg1 == UpstreamNetworkMonitor.NOTIFY_LOCAL_PREFIXES) {
+                mOffload.sendOffloadExemptPrefixes((Set<IpPrefix>) o);
+                return;
+            }
+
+            final UpstreamNetworkState ns = (UpstreamNetworkState) o;
+            switch (arg1) {
+                case UpstreamNetworkMonitor.EVENT_ON_LINKPROPERTIES:
+                    mPrivateAddressCoordinator.updateUpstreamPrefix(ns);
+                    break;
+                case UpstreamNetworkMonitor.EVENT_ON_LOST:
+                    mPrivateAddressCoordinator.removeUpstreamPrefix(ns.network);
+                    break;
+            }
+
+            if (ns == null || !pertainsToCurrentUpstream(ns)) {
+                // TODO: In future, this is where upstream evaluation and selection
+                // could be handled for notifications which include sufficient data.
+                // For example, after CONNECTIVITY_ACTION listening is removed, here
+                // is where we could observe a Wi-Fi network becoming available and
+                // passing validation.
+                if (mCurrentUpstreamIfaceSet == null) {
+                    // If we have no upstream interface, try to run through upstream
+                    // selection again.  If, for example, IPv4 connectivity has shown up
+                    // after IPv6 (e.g., 464xlat became available) we want the chance to
+                    // notice and act accordingly.
+                    chooseUpstreamType(false);
+                }
+                return;
+            }
+
+            switch (arg1) {
+                case UpstreamNetworkMonitor.EVENT_ON_CAPABILITIES:
+                    if (ns.network.equals(mTetherUpstream)) {
+                        mNotificationUpdater.onUpstreamCapabilitiesChanged(ns.networkCapabilities);
+                    }
+                    handleNewUpstreamNetworkState(ns);
+                    break;
+                case UpstreamNetworkMonitor.EVENT_ON_LINKPROPERTIES:
+                    chooseUpstreamType(false);
+                    break;
+                case UpstreamNetworkMonitor.EVENT_ON_LOST:
+                    // TODO: Re-evaluate possible upstreams. Currently upstream
+                    // reevaluation is triggered via received CONNECTIVITY_ACTION
+                    // broadcasts that result in being passed a
+                    // TetherMainSM.CMD_UPSTREAM_CHANGED.
+                    handleNewUpstreamNetworkState(null);
+                    break;
+                default:
+                    mLog.e("Unknown arg1 value: " + arg1);
+                    break;
+            }
+        }
+
+        class TetherModeAliveState extends State {
+            boolean mUpstreamWanted = false;
+            boolean mTryCell = true;
+
+            @Override
+            public void enter() {
+                // If turning on main tether settings fails, we have already
+                // transitioned to an error state; exit early.
+                if (!turnOnMainTetherSettings()) {
+                    return;
+                }
+
+                mPrivateAddressCoordinator.maybeRemoveDeprecatedUpstreams();
+                mUpstreamNetworkMonitor.startObserveAllNetworks();
+
+                // TODO: De-duplicate with updateUpstreamWanted() below.
+                if (upstreamWanted()) {
+                    mUpstreamWanted = true;
+                    mOffload.start();
+                    chooseUpstreamType(true);
+                    mTryCell = false;
+                }
+
+                // TODO: Check the upstream interface if it is managed by BPF offload.
+                mBpfCoordinator.startPolling();
+            }
+
+            @Override
+            public void exit() {
+                mOffload.stop();
+                mUpstreamNetworkMonitor.stop();
+                notifyDownstreamsOfNewUpstreamIface(null);
+                handleNewUpstreamNetworkState(null);
+                if (mTetherUpstream != null) {
+                    mTetherUpstream = null;
+                    reportUpstreamChanged(null);
+                }
+                mBpfCoordinator.stopPolling();
+            }
+
+            private boolean updateUpstreamWanted() {
+                final boolean previousUpstreamWanted = mUpstreamWanted;
+                mUpstreamWanted = upstreamWanted();
+                if (mUpstreamWanted != previousUpstreamWanted) {
+                    if (mUpstreamWanted) {
+                        mOffload.start();
+                    } else {
+                        mOffload.stop();
+                    }
+                }
+                return previousUpstreamWanted;
+            }
+
+            @Override
+            public boolean processMessage(Message message) {
+                logMessage(this, message.what);
+                boolean retValue = true;
+                switch (message.what) {
+                    case EVENT_IFACE_SERVING_STATE_ACTIVE: {
+                        IpServer who = (IpServer) message.obj;
+                        if (VDBG) Log.d(TAG, "Tether Mode requested by " + who);
+                        handleInterfaceServingStateActive(message.arg1, who);
+                        who.sendMessage(IpServer.CMD_TETHER_CONNECTION_CHANGED,
+                                mCurrentUpstreamIfaceSet);
+                        // If there has been a change and an upstream is now
+                        // desired, kick off the selection process.
+                        final boolean previousUpstreamWanted = updateUpstreamWanted();
+                        if (!previousUpstreamWanted && mUpstreamWanted) {
+                            chooseUpstreamType(true);
+                        }
+                        break;
+                    }
+                    case EVENT_IFACE_SERVING_STATE_INACTIVE: {
+                        IpServer who = (IpServer) message.obj;
+                        if (VDBG) Log.d(TAG, "Tether Mode unrequested by " + who);
+                        handleInterfaceServingStateInactive(who);
+
+                        if (mNotifyList.isEmpty()) {
+                            // This transitions us out of TetherModeAliveState,
+                            // either to InitialState or an error state.
+                            turnOffMainTetherSettings();
+                            break;
+                        }
+
+                        if (DBG) {
+                            Log.d(TAG, "TetherModeAlive still has " + mNotifyList.size()
+                                    + " live requests:");
+                            for (IpServer o : mNotifyList) {
+                                Log.d(TAG, "  " + o);
+                            }
+                        }
+                        // If there has been a change and an upstream is no
+                        // longer desired, release any mobile requests.
+                        final boolean previousUpstreamWanted = updateUpstreamWanted();
+                        if (previousUpstreamWanted && !mUpstreamWanted) {
+                            mUpstreamNetworkMonitor.releaseMobileNetworkRequest();
+                        }
+                        break;
+                    }
+                    case EVENT_IFACE_UPDATE_LINKPROPERTIES: {
+                        final LinkProperties newLp = (LinkProperties) message.obj;
+                        if (message.arg1 == IpServer.STATE_TETHERED) {
+                            mOffload.updateDownstreamLinkProperties(newLp);
+                        } else {
+                            mOffload.excludeDownstreamInterface(newLp.getInterfaceName());
+                        }
+                        break;
+                    }
+                    case EVENT_UPSTREAM_PERMISSION_CHANGED:
+                    case CMD_UPSTREAM_CHANGED:
+                        updateUpstreamWanted();
+                        if (!mUpstreamWanted) break;
+
+                        // Need to try DUN immediately if Wi-Fi goes down.
+                        chooseUpstreamType(true);
+                        mTryCell = false;
+                        break;
+                    case CMD_RETRY_UPSTREAM:
+                        updateUpstreamWanted();
+                        if (!mUpstreamWanted) break;
+
+                        chooseUpstreamType(mTryCell);
+                        mTryCell = !mTryCell;
+                        break;
+                    case EVENT_UPSTREAM_CALLBACK: {
+                        updateUpstreamWanted();
+                        if (mUpstreamWanted) {
+                            handleUpstreamNetworkMonitorCallback(message.arg1, message.obj);
+                        }
+                        break;
+                    }
+                    default:
+                        retValue = false;
+                        break;
+                }
+                return retValue;
+            }
+        }
+
+        class ErrorState extends State {
+            private int mErrorNotification;
+
+            @Override
+            public boolean processMessage(Message message) {
+                boolean retValue = true;
+                switch (message.what) {
+                    case EVENT_IFACE_SERVING_STATE_ACTIVE:
+                        IpServer who = (IpServer) message.obj;
+                        who.sendMessage(mErrorNotification);
+                        break;
+                    case CMD_CLEAR_ERROR:
+                        mErrorNotification = TETHER_ERROR_NO_ERROR;
+                        transitionTo(mInitialState);
+                        break;
+                    default:
+                        retValue = false;
+                }
+                return retValue;
+            }
+
+            void notify(int msgType) {
+                mErrorNotification = msgType;
+                for (IpServer ipServer : mNotifyList) {
+                    ipServer.sendMessage(msgType);
+                }
+            }
+
+        }
+
+        class SetIpForwardingEnabledErrorState extends ErrorState {
+            @Override
+            public void enter() {
+                Log.e(TAG, "Error in setIpForwardingEnabled");
+                notify(IpServer.CMD_IP_FORWARDING_ENABLE_ERROR);
+            }
+        }
+
+        class SetIpForwardingDisabledErrorState extends ErrorState {
+            @Override
+            public void enter() {
+                Log.e(TAG, "Error in setIpForwardingDisabled");
+                notify(IpServer.CMD_IP_FORWARDING_DISABLE_ERROR);
+            }
+        }
+
+        class StartTetheringErrorState extends ErrorState {
+            @Override
+            public void enter() {
+                Log.e(TAG, "Error in startTethering");
+                notify(IpServer.CMD_START_TETHERING_ERROR);
+                try {
+                    mNetd.ipfwdDisableForwarding(TAG);
+                } catch (RemoteException | ServiceSpecificException e) { }
+            }
+        }
+
+        class StopTetheringErrorState extends ErrorState {
+            @Override
+            public void enter() {
+                Log.e(TAG, "Error in stopTethering");
+                notify(IpServer.CMD_STOP_TETHERING_ERROR);
+                try {
+                    mNetd.ipfwdDisableForwarding(TAG);
+                } catch (RemoteException | ServiceSpecificException e) { }
+            }
+        }
+
+        class SetDnsForwardersErrorState extends ErrorState {
+            @Override
+            public void enter() {
+                Log.e(TAG, "Error in setDnsForwarders");
+                notify(IpServer.CMD_SET_DNS_FORWARDERS_ERROR);
+                try {
+                    mNetd.tetherStop();
+                } catch (RemoteException | ServiceSpecificException e) { }
+                try {
+                    mNetd.ipfwdDisableForwarding(TAG);
+                } catch (RemoteException | ServiceSpecificException e) { }
+            }
+        }
+
+        // A wrapper class to handle multiple situations where several calls to
+        // the OffloadController need to happen together.
+        //
+        // TODO: This suggests that the interface between OffloadController and
+        // Tethering is in need of improvement. Refactor these calls into the
+        // OffloadController implementation.
+        class OffloadWrapper {
+            public void start() {
+                final int status = mOffloadController.start() ? TETHER_HARDWARE_OFFLOAD_STARTED
+                        : TETHER_HARDWARE_OFFLOAD_FAILED;
+                updateOffloadStatus(status);
+                sendOffloadExemptPrefixes();
+            }
+
+            public void stop() {
+                mOffloadController.stop();
+                updateOffloadStatus(TETHER_HARDWARE_OFFLOAD_STOPPED);
+            }
+
+            public void updateUpstreamNetworkState(UpstreamNetworkState ns) {
+                mOffloadController.setUpstreamLinkProperties(
+                        (ns != null) ? ns.linkProperties : null);
+            }
+
+            public void updateDownstreamLinkProperties(LinkProperties newLp) {
+                // Update the list of offload-exempt prefixes before adding
+                // new prefixes on downstream interfaces to the offload HAL.
+                sendOffloadExemptPrefixes();
+                mOffloadController.notifyDownstreamLinkProperties(newLp);
+            }
+
+            public void excludeDownstreamInterface(String ifname) {
+                // This and other interfaces may be in local-only hotspot mode;
+                // resend all local prefixes to the OffloadController.
+                sendOffloadExemptPrefixes();
+                mOffloadController.removeDownstreamInterface(ifname);
+            }
+
+            public void sendOffloadExemptPrefixes() {
+                sendOffloadExemptPrefixes(mUpstreamNetworkMonitor.getLocalPrefixes());
+            }
+
+            public void sendOffloadExemptPrefixes(final Set<IpPrefix> localPrefixes) {
+                // Add in well-known minimum set.
+                PrefixUtils.addNonForwardablePrefixes(localPrefixes);
+                // Add tragically hardcoded prefixes.
+                localPrefixes.add(PrefixUtils.DEFAULT_WIFI_P2P_PREFIX);
+
+                // Maybe add prefixes or addresses for downstreams, depending on
+                // the IP serving mode of each.
+                for (IpServer ipServer : mNotifyList) {
+                    final LinkProperties lp = ipServer.linkProperties();
+
+                    switch (ipServer.servingMode()) {
+                        case IpServer.STATE_UNAVAILABLE:
+                        case IpServer.STATE_AVAILABLE:
+                            // No usable LinkProperties in these states.
+                            continue;
+                        case IpServer.STATE_TETHERED:
+                            // Only add IPv4 /32 and IPv6 /128 prefixes. The
+                            // directly-connected prefixes will be sent as
+                            // downstream "offload-able" prefixes.
+                            for (LinkAddress addr : lp.getAllLinkAddresses()) {
+                                final InetAddress ip = addr.getAddress();
+                                if (ip.isLinkLocalAddress()) continue;
+                                localPrefixes.add(PrefixUtils.ipAddressAsPrefix(ip));
+                            }
+                            break;
+                        case IpServer.STATE_LOCAL_ONLY:
+                            // Add prefixes covering all local IPs.
+                            localPrefixes.addAll(PrefixUtils.localPrefixesFrom(lp));
+                            break;
+                    }
+                }
+
+                mOffloadController.setLocalPrefixes(localPrefixes);
+            }
+
+            private void updateOffloadStatus(final int newStatus) {
+                if (newStatus == mOffloadStatus) return;
+
+                mOffloadStatus = newStatus;
+                reportOffloadStatusChanged(mOffloadStatus);
+            }
+        }
+    }
+
+    private void startTrackDefaultNetwork() {
+        mUpstreamNetworkMonitor.startTrackDefaultNetwork(mDeps.getDefaultNetworkRequest(),
+                mEntitlementMgr);
+    }
+
+    /** Get the latest value of the tethering entitlement check. */
+    void requestLatestTetheringEntitlementResult(int type, ResultReceiver receiver,
+            boolean showEntitlementUi) {
+        if (receiver == null) return;
+
+        mHandler.post(() -> {
+            mEntitlementMgr.requestLatestTetheringEntitlementResult(type, receiver,
+                    showEntitlementUi);
+        });
+    }
+
+    /** Register tethering event callback */
+    void registerTetheringEventCallback(ITetheringEventCallback callback) {
+        final boolean hasListPermission =
+                hasCallingPermission(NETWORK_SETTINGS)
+                        || hasCallingPermission(PERMISSION_MAINLINE_NETWORK_STACK)
+                        || hasCallingPermission(NETWORK_STACK);
+        mHandler.post(() -> {
+            mTetheringEventCallbacks.register(callback, new CallbackCookie(hasListPermission));
+            final TetheringCallbackStartedParcel parcel = new TetheringCallbackStartedParcel();
+            parcel.tetheringSupported = isTetheringSupported();
+            parcel.upstreamNetwork = mTetherUpstream;
+            parcel.config = mConfig.toStableParcelable();
+            parcel.states =
+                    mTetherStatesParcel != null ? mTetherStatesParcel : emptyTetherStatesParcel();
+            parcel.tetheredClients = hasListPermission
+                    ? mConnectedClientsTracker.getLastTetheredClients()
+                    : Collections.emptyList();
+            parcel.offloadStatus = mOffloadStatus;
+            try {
+                callback.onCallbackStarted(parcel);
+            } catch (RemoteException e) {
+                // Not really very much to do here.
+            }
+        });
+    }
+
+    private TetherStatesParcel emptyTetherStatesParcel() {
+        final TetherStatesParcel parcel = new TetherStatesParcel();
+        parcel.availableList = new String[0];
+        parcel.tetheredList = new String[0];
+        parcel.localOnlyList = new String[0];
+        parcel.erroredIfaceList = new String[0];
+        parcel.lastErrorList = new int[0];
+
+        return parcel;
+    }
+
+    private boolean hasCallingPermission(@NonNull String permission) {
+        return mContext.checkCallingOrSelfPermission(permission) == PERMISSION_GRANTED;
+    }
+
+    /** Unregister tethering event callback */
+    void unregisterTetheringEventCallback(ITetheringEventCallback callback) {
+        mHandler.post(() -> {
+            mTetheringEventCallbacks.unregister(callback);
+        });
+    }
+
+    private void reportUpstreamChanged(UpstreamNetworkState ns) {
+        final int length = mTetheringEventCallbacks.beginBroadcast();
+        final Network network = (ns != null) ? ns.network : null;
+        final NetworkCapabilities capabilities = (ns != null) ? ns.networkCapabilities : null;
+        try {
+            for (int i = 0; i < length; i++) {
+                try {
+                    mTetheringEventCallbacks.getBroadcastItem(i).onUpstreamChanged(network);
+                } catch (RemoteException e) {
+                    // Not really very much to do here.
+                }
+            }
+        } finally {
+            mTetheringEventCallbacks.finishBroadcast();
+        }
+        // Need to notify capabilities change after upstream network changed because new network's
+        // capabilities should be checked every time.
+        mNotificationUpdater.onUpstreamCapabilitiesChanged(capabilities);
+    }
+
+    private void reportConfigurationChanged(TetheringConfigurationParcel config) {
+        final int length = mTetheringEventCallbacks.beginBroadcast();
+        try {
+            for (int i = 0; i < length; i++) {
+                try {
+                    mTetheringEventCallbacks.getBroadcastItem(i).onConfigurationChanged(config);
+                    // TODO(b/148139325): send tetheringSupported on configuration change
+                } catch (RemoteException e) {
+                    // Not really very much to do here.
+                }
+            }
+        } finally {
+            mTetheringEventCallbacks.finishBroadcast();
+        }
+    }
+
+    private void reportTetherStateChanged(TetherStatesParcel states) {
+        final int length = mTetheringEventCallbacks.beginBroadcast();
+        try {
+            for (int i = 0; i < length; i++) {
+                try {
+                    mTetheringEventCallbacks.getBroadcastItem(i).onTetherStatesChanged(states);
+                } catch (RemoteException e) {
+                    // Not really very much to do here.
+                }
+            }
+        } finally {
+            mTetheringEventCallbacks.finishBroadcast();
+        }
+    }
+
+    private void reportTetherClientsChanged(List<TetheredClient> clients) {
+        final int length = mTetheringEventCallbacks.beginBroadcast();
+        try {
+            for (int i = 0; i < length; i++) {
+                try {
+                    final CallbackCookie cookie =
+                            (CallbackCookie) mTetheringEventCallbacks.getBroadcastCookie(i);
+                    if (!cookie.hasListClientsPermission) continue;
+                    mTetheringEventCallbacks.getBroadcastItem(i).onTetherClientsChanged(clients);
+                } catch (RemoteException e) {
+                    // Not really very much to do here.
+                }
+            }
+        } finally {
+            mTetheringEventCallbacks.finishBroadcast();
+        }
+    }
+
+    private void reportOffloadStatusChanged(final int status) {
+        final int length = mTetheringEventCallbacks.beginBroadcast();
+        try {
+            for (int i = 0; i < length; i++) {
+                try {
+                    mTetheringEventCallbacks.getBroadcastItem(i).onOffloadStatusChanged(status);
+                } catch (RemoteException e) {
+                    // Not really very much to do here.
+                }
+            }
+        } finally {
+            mTetheringEventCallbacks.finishBroadcast();
+        }
+    }
+
+    // if ro.tether.denied = true we default to no tethering
+    // gservices could set the secure setting to 1 though to enable it on a build where it
+    // had previously been turned off.
+    boolean isTetheringSupported() {
+        final int defaultVal = mDeps.isTetheringDenied() ? 0 : 1;
+        final boolean tetherSupported = Settings.Global.getInt(mContext.getContentResolver(),
+                Settings.Global.TETHER_SUPPORTED, defaultVal) != 0;
+        final boolean tetherEnabledInSettings = tetherSupported
+                && !mUserManager.hasUserRestriction(UserManager.DISALLOW_CONFIG_TETHERING);
+
+        return tetherEnabledInSettings && hasTetherableConfiguration()
+                && !isProvisioningNeededButUnavailable();
+    }
+
+    void dump(@NonNull FileDescriptor fd, @NonNull PrintWriter writer, @Nullable String[] args) {
+        // Binder.java closes the resource for us.
+        @SuppressWarnings("resource")
+        final IndentingPrintWriter pw = new IndentingPrintWriter(writer, "  ");
+        if (mContext.checkCallingOrSelfPermission(android.Manifest.permission.DUMP)
+                != PERMISSION_GRANTED) {
+            pw.println("Permission Denial: can't dump.");
+            return;
+        }
+
+        pw.println("Tethering:");
+        pw.increaseIndent();
+
+        pw.println("Configuration:");
+        pw.increaseIndent();
+        final TetheringConfiguration cfg = mConfig;
+        cfg.dump(pw);
+        pw.decreaseIndent();
+
+        pw.println("Entitlement:");
+        pw.increaseIndent();
+        mEntitlementMgr.dump(pw);
+        pw.decreaseIndent();
+
+        synchronized (mPublicSync) {
+            pw.println("Tether state:");
+            pw.increaseIndent();
+            for (int i = 0; i < mTetherStates.size(); i++) {
+                final String iface = mTetherStates.keyAt(i);
+                final TetherState tetherState = mTetherStates.valueAt(i);
+                pw.print(iface + " - ");
+
+                switch (tetherState.lastState) {
+                    case IpServer.STATE_UNAVAILABLE:
+                        pw.print("UnavailableState");
+                        break;
+                    case IpServer.STATE_AVAILABLE:
+                        pw.print("AvailableState");
+                        break;
+                    case IpServer.STATE_TETHERED:
+                        pw.print("TetheredState");
+                        break;
+                    case IpServer.STATE_LOCAL_ONLY:
+                        pw.print("LocalHotspotState");
+                        break;
+                    default:
+                        pw.print("UnknownState");
+                        break;
+                }
+                pw.println(" - lastError = " + tetherState.lastError);
+            }
+            pw.println("Upstream wanted: " + upstreamWanted());
+            pw.println("Current upstream interface(s): " + mCurrentUpstreamIfaceSet);
+            pw.decreaseIndent();
+        }
+
+        pw.println("Hardware offload:");
+        pw.increaseIndent();
+        mOffloadController.dump(pw);
+        pw.decreaseIndent();
+
+        pw.println("BPF offload:");
+        pw.increaseIndent();
+        mBpfCoordinator.dump(pw);
+        pw.decreaseIndent();
+
+        pw.println("Private address coordinator:");
+        pw.increaseIndent();
+        mPrivateAddressCoordinator.dump(pw);
+        pw.decreaseIndent();
+
+        pw.println("Log:");
+        pw.increaseIndent();
+        if (argsContain(args, "--short")) {
+            pw.println("<log removed for brevity>");
+        } else {
+            mLog.dump(fd, pw, args);
+        }
+        pw.decreaseIndent();
+
+        pw.decreaseIndent();
+    }
+
+    private static boolean argsContain(String[] args, String target) {
+        for (String arg : args) {
+            if (target.equals(arg)) return true;
+        }
+        return false;
+    }
+
+    private void updateConnectedClients(final List<WifiClient> wifiClients) {
+        if (mConnectedClientsTracker.updateConnectedClients(mForwardedDownstreams, wifiClients)) {
+            reportTetherClientsChanged(mConnectedClientsTracker.getLastTetheredClients());
+        }
+    }
+
+    private IpServer.Callback makeControlCallback() {
+        return new IpServer.Callback() {
+            @Override
+            public void updateInterfaceState(IpServer who, int state, int lastError) {
+                notifyInterfaceStateChange(who, state, lastError);
+            }
+
+            @Override
+            public void updateLinkProperties(IpServer who, LinkProperties newLp) {
+                notifyLinkPropertiesChanged(who, newLp);
+            }
+
+            @Override
+            public void dhcpLeasesChanged() {
+                updateConnectedClients(null /* wifiClients */);
+            }
+
+            @Override
+            public void requestEnableTethering(int tetheringType, boolean enabled) {
+                enableTetheringInternal(tetheringType, enabled, null);
+            }
+        };
+    }
+
+    // TODO: Move into TetherMainSM.
+    private void notifyInterfaceStateChange(IpServer who, int state, int error) {
+        final String iface = who.interfaceName();
+        synchronized (mPublicSync) {
+            final TetherState tetherState = mTetherStates.get(iface);
+            if (tetherState != null && tetherState.ipServer.equals(who)) {
+                tetherState.lastState = state;
+                tetherState.lastError = error;
+            } else {
+                if (DBG) Log.d(TAG, "got notification from stale iface " + iface);
+            }
+        }
+
+        mLog.log(String.format("OBSERVED iface=%s state=%s error=%s", iface, state, error));
+
+        // If TetherMainSM is in ErrorState, TetherMainSM stays there.
+        // Thus we give a chance for TetherMainSM to recover to InitialState
+        // by sending CMD_CLEAR_ERROR
+        if (error == TETHER_ERROR_INTERNAL_ERROR) {
+            mTetherMainSM.sendMessage(TetherMainSM.CMD_CLEAR_ERROR, who);
+        }
+        int which;
+        switch (state) {
+            case IpServer.STATE_UNAVAILABLE:
+            case IpServer.STATE_AVAILABLE:
+                which = TetherMainSM.EVENT_IFACE_SERVING_STATE_INACTIVE;
+                break;
+            case IpServer.STATE_TETHERED:
+            case IpServer.STATE_LOCAL_ONLY:
+                which = TetherMainSM.EVENT_IFACE_SERVING_STATE_ACTIVE;
+                break;
+            default:
+                Log.wtf(TAG, "Unknown interface state: " + state);
+                return;
+        }
+        mTetherMainSM.sendMessage(which, state, 0, who);
+        sendTetherStateChangedBroadcast();
+    }
+
+    private void notifyLinkPropertiesChanged(IpServer who, LinkProperties newLp) {
+        final String iface = who.interfaceName();
+        final int state;
+        synchronized (mPublicSync) {
+            final TetherState tetherState = mTetherStates.get(iface);
+            if (tetherState != null && tetherState.ipServer.equals(who)) {
+                state = tetherState.lastState;
+            } else {
+                mLog.log("got notification from stale iface " + iface);
+                return;
+            }
+        }
+
+        mLog.log(String.format(
+                "OBSERVED LinkProperties update iface=%s state=%s lp=%s",
+                iface, IpServer.getStateString(state), newLp));
+        final int which = TetherMainSM.EVENT_IFACE_UPDATE_LINKPROPERTIES;
+        mTetherMainSM.sendMessage(which, state, 0, newLp);
+    }
+
+    private void maybeTrackNewInterfaceLocked(final String iface) {
+        // If we don't care about this type of interface, ignore.
+        final int interfaceType = ifaceNameToType(iface);
+        if (interfaceType == TETHERING_INVALID) {
+            mLog.log(iface + " is not a tetherable iface, ignoring");
+            return;
+        }
+        maybeTrackNewInterfaceLocked(iface, interfaceType);
+    }
+
+    private void maybeTrackNewInterfaceLocked(final String iface, int interfaceType) {
+        // If we have already started a TISM for this interface, skip.
+        if (mTetherStates.containsKey(iface)) {
+            mLog.log("active iface (" + iface + ") reported as added, ignoring");
+            return;
+        }
+
+        mLog.log("adding TetheringInterfaceStateMachine for: " + iface);
+        final TetherState tetherState = new TetherState(
+                new IpServer(iface, mLooper, interfaceType, mLog, mNetd, mBpfCoordinator,
+                             makeControlCallback(), mConfig.enableLegacyDhcpServer,
+                             mConfig.isBpfOffloadEnabled(), mPrivateAddressCoordinator,
+                             mDeps.getIpServerDependencies()));
+        mTetherStates.put(iface, tetherState);
+        tetherState.ipServer.start();
+    }
+
+    private void stopTrackingInterfaceLocked(final String iface) {
+        final TetherState tetherState = mTetherStates.get(iface);
+        if (tetherState == null) {
+            mLog.log("attempting to remove unknown iface (" + iface + "), ignoring");
+            return;
+        }
+        tetherState.ipServer.stop();
+        mLog.log("removing TetheringInterfaceStateMachine for: " + iface);
+        mTetherStates.remove(iface);
+    }
+
+    private static String[] copy(String[] strarray) {
+        return Arrays.copyOf(strarray, strarray.length);
+    }
+}
diff --git a/Tethering/src/com/android/networkstack/tethering/TetheringConfiguration.java b/Tethering/src/com/android/networkstack/tethering/TetheringConfiguration.java
new file mode 100644
index 0000000..799637c
--- /dev/null
+++ b/Tethering/src/com/android/networkstack/tethering/TetheringConfiguration.java
@@ -0,0 +1,521 @@
+/*
+ * Copyright (C) 2017 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.android.networkstack.tethering;
+
+import static android.content.Context.TELEPHONY_SERVICE;
+import static android.net.ConnectivityManager.TYPE_ETHERNET;
+import static android.net.ConnectivityManager.TYPE_MOBILE;
+import static android.net.ConnectivityManager.TYPE_MOBILE_DUN;
+import static android.net.ConnectivityManager.TYPE_MOBILE_HIPRI;
+import static android.provider.DeviceConfig.NAMESPACE_CONNECTIVITY;
+
+import android.content.Context;
+import android.content.res.Resources;
+import android.net.TetheringConfigurationParcel;
+import android.net.util.SharedLog;
+import android.provider.DeviceConfig;
+import android.telephony.SubscriptionManager;
+import android.telephony.TelephonyManager;
+import android.text.TextUtils;
+
+import com.android.internal.annotations.VisibleForTesting;
+
+import java.io.PrintWriter;
+import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.Collection;
+import java.util.StringJoiner;
+
+/**
+ * A utility class to encapsulate the various tethering configuration elements.
+ *
+ * This configuration data includes elements describing upstream properties
+ * (preferred and required types of upstream connectivity as well as default
+ * DNS servers to use if none are available) and downstream properties (such
+ * as regular expressions use to match suitable downstream interfaces and the
+ * DHCPv4 ranges to use).
+ *
+ * @hide
+ */
+public class TetheringConfiguration {
+    private static final String TAG = TetheringConfiguration.class.getSimpleName();
+
+    private static final String[] EMPTY_STRING_ARRAY = new String[0];
+
+    // Default ranges used for the legacy DHCP server.
+    // USB is  192.168.42.1 and 255.255.255.0
+    // Wifi is 192.168.43.1 and 255.255.255.0
+    // BT is limited to max default of 5 connections. 192.168.44.1 to 192.168.48.1
+    // with 255.255.255.0
+    // P2P is 192.168.49.1 and 255.255.255.0
+    private static final String[] LEGACY_DHCP_DEFAULT_RANGE = {
+        "192.168.42.2", "192.168.42.254", "192.168.43.2", "192.168.43.254",
+        "192.168.44.2", "192.168.44.254", "192.168.45.2", "192.168.45.254",
+        "192.168.46.2", "192.168.46.254", "192.168.47.2", "192.168.47.254",
+        "192.168.48.2", "192.168.48.254", "192.168.49.2", "192.168.49.254",
+    };
+
+    private static final String[] DEFAULT_IPV4_DNS = {"8.8.4.4", "8.8.8.8"};
+
+    /**
+     * Override enabling BPF offload configuration for tethering.
+     */
+    public static final String OVERRIDE_TETHER_ENABLE_BPF_OFFLOAD =
+            "override_tether_enable_bpf_offload";
+
+    /**
+     * Use the old dnsmasq DHCP server for tethering instead of the framework implementation.
+     */
+    public static final String TETHER_ENABLE_LEGACY_DHCP_SERVER =
+            "tether_enable_legacy_dhcp_server";
+
+    public static final String USE_LEGACY_WIFI_P2P_DEDICATED_IP =
+            "use_legacy_wifi_p2p_dedicated_ip";
+
+    /**
+     * Flag use to enable select all prefix ranges feature.
+     * TODO: Remove this flag if there are no problems after M-2020-12 rolls out.
+     */
+    public static final String TETHER_ENABLE_SELECT_ALL_PREFIX_RANGES =
+            "tether_enable_select_all_prefix_ranges";
+
+    /**
+     * Default value that used to periodic polls tether offload stats from tethering offload HAL
+     * to make the data warnings work.
+     */
+    public static final int DEFAULT_TETHER_OFFLOAD_POLL_INTERVAL_MS = 5000;
+
+    public final String[] tetherableUsbRegexs;
+    public final String[] tetherableWifiRegexs;
+    public final String[] tetherableWigigRegexs;
+    public final String[] tetherableWifiP2pRegexs;
+    public final String[] tetherableBluetoothRegexs;
+    public final String[] tetherableNcmRegexs;
+    public final boolean isDunRequired;
+    public final boolean chooseUpstreamAutomatically;
+    public final Collection<Integer> preferredUpstreamIfaceTypes;
+    public final String[] legacyDhcpRanges;
+    public final String[] defaultIPv4DNS;
+    public final boolean enableLegacyDhcpServer;
+
+    public final String[] provisioningApp;
+    public final String provisioningAppNoUi;
+    public final int provisioningCheckPeriod;
+    public final String provisioningResponse;
+
+    public final int activeDataSubId;
+
+    private final int mOffloadPollInterval;
+    // TODO: Add to TetheringConfigurationParcel if required.
+    private final boolean mEnableBpfOffload;
+    private final boolean mEnableWifiP2pDedicatedIp;
+
+    private final boolean mEnableSelectAllPrefixRange;
+
+    public TetheringConfiguration(Context ctx, SharedLog log, int id) {
+        final SharedLog configLog = log.forSubComponent("config");
+
+        activeDataSubId = id;
+        Resources res = getResources(ctx, activeDataSubId);
+
+        tetherableUsbRegexs = getResourceStringArray(res, R.array.config_tether_usb_regexs);
+        tetherableNcmRegexs = getResourceStringArray(res, R.array.config_tether_ncm_regexs);
+        // TODO: Evaluate deleting this altogether now that Wi-Fi always passes
+        // us an interface name. Careful consideration needs to be given to
+        // implications for Settings and for provisioning checks.
+        tetherableWifiRegexs = getResourceStringArray(res, R.array.config_tether_wifi_regexs);
+        tetherableWigigRegexs = getResourceStringArray(res, R.array.config_tether_wigig_regexs);
+        tetherableWifiP2pRegexs = getResourceStringArray(
+                res, R.array.config_tether_wifi_p2p_regexs);
+        tetherableBluetoothRegexs = getResourceStringArray(
+                res, R.array.config_tether_bluetooth_regexs);
+
+        isDunRequired = checkDunRequired(ctx);
+
+        chooseUpstreamAutomatically = getResourceBoolean(
+                res, R.bool.config_tether_upstream_automatic, false /** defaultValue */);
+        preferredUpstreamIfaceTypes = getUpstreamIfaceTypes(res, isDunRequired);
+
+        legacyDhcpRanges = getLegacyDhcpRanges(res);
+        defaultIPv4DNS = copy(DEFAULT_IPV4_DNS);
+        mEnableBpfOffload = getEnableBpfOffload(res);
+        enableLegacyDhcpServer = getEnableLegacyDhcpServer(res);
+
+        provisioningApp = getResourceStringArray(res, R.array.config_mobile_hotspot_provision_app);
+        provisioningAppNoUi = getResourceString(res,
+                R.string.config_mobile_hotspot_provision_app_no_ui);
+        provisioningCheckPeriod = getResourceInteger(res,
+                R.integer.config_mobile_hotspot_provision_check_period,
+                0 /* No periodic re-check */);
+        provisioningResponse = getResourceString(res,
+                R.string.config_mobile_hotspot_provision_response);
+
+        mOffloadPollInterval = getResourceInteger(res,
+                R.integer.config_tether_offload_poll_interval,
+                DEFAULT_TETHER_OFFLOAD_POLL_INTERVAL_MS);
+
+        mEnableWifiP2pDedicatedIp = getResourceBoolean(res,
+                R.bool.config_tether_enable_legacy_wifi_p2p_dedicated_ip,
+                false /* defaultValue */);
+
+        // Flags should normally not be booleans, but this is a kill-switch flag that is only used
+        // to turn off the feature, so binary rollback problems do not apply.
+        mEnableSelectAllPrefixRange = getDeviceConfigBoolean(
+                TETHER_ENABLE_SELECT_ALL_PREFIX_RANGES, true /* defaultValue */);
+
+        configLog.log(toString());
+    }
+
+    /** Check whether input interface belong to usb.*/
+    public boolean isUsb(String iface) {
+        return matchesDownstreamRegexs(iface, tetherableUsbRegexs);
+    }
+
+    /** Check whether input interface belong to wifi.*/
+    public boolean isWifi(String iface) {
+        return matchesDownstreamRegexs(iface, tetherableWifiRegexs);
+    }
+
+    /** Check whether input interface belong to wigig.*/
+    public boolean isWigig(String iface) {
+        return matchesDownstreamRegexs(iface, tetherableWigigRegexs);
+    }
+
+    /** Check whether this interface is Wifi P2P interface. */
+    public boolean isWifiP2p(String iface) {
+        return matchesDownstreamRegexs(iface, tetherableWifiP2pRegexs);
+    }
+
+    /** Check whether using legacy mode for wifi P2P. */
+    public boolean isWifiP2pLegacyTetheringMode() {
+        return (tetherableWifiP2pRegexs == null || tetherableWifiP2pRegexs.length == 0);
+    }
+
+    /** Check whether input interface belong to bluetooth.*/
+    public boolean isBluetooth(String iface) {
+        return matchesDownstreamRegexs(iface, tetherableBluetoothRegexs);
+    }
+
+    /** Check if interface is ncm */
+    public boolean isNcm(String iface) {
+        return matchesDownstreamRegexs(iface, tetherableNcmRegexs);
+    }
+
+    /** Check whether no ui entitlement application is available.*/
+    public boolean hasMobileHotspotProvisionApp() {
+        return !TextUtils.isEmpty(provisioningAppNoUi);
+    }
+
+    /** Check whether dedicated wifi p2p address is enabled. */
+    public boolean shouldEnableWifiP2pDedicatedIp() {
+        return mEnableWifiP2pDedicatedIp;
+    }
+
+    /** Does the dumping.*/
+    public void dump(PrintWriter pw) {
+        pw.print("activeDataSubId: ");
+        pw.println(activeDataSubId);
+
+        dumpStringArray(pw, "tetherableUsbRegexs", tetherableUsbRegexs);
+        dumpStringArray(pw, "tetherableWifiRegexs", tetherableWifiRegexs);
+        dumpStringArray(pw, "tetherableWifiP2pRegexs", tetherableWifiP2pRegexs);
+        dumpStringArray(pw, "tetherableBluetoothRegexs", tetherableBluetoothRegexs);
+        dumpStringArray(pw, "tetherableNcmRegexs", tetherableNcmRegexs);
+
+        pw.print("isDunRequired: ");
+        pw.println(isDunRequired);
+
+        pw.print("chooseUpstreamAutomatically: ");
+        pw.println(chooseUpstreamAutomatically);
+        pw.print("legacyPreredUpstreamIfaceTypes: ");
+        pw.println(Arrays.toString(toIntArray(preferredUpstreamIfaceTypes)));
+
+        dumpStringArray(pw, "legacyDhcpRanges", legacyDhcpRanges);
+        dumpStringArray(pw, "defaultIPv4DNS", defaultIPv4DNS);
+
+        pw.print("offloadPollInterval: ");
+        pw.println(mOffloadPollInterval);
+
+        dumpStringArray(pw, "provisioningApp", provisioningApp);
+        pw.print("provisioningAppNoUi: ");
+        pw.println(provisioningAppNoUi);
+
+        pw.print("enableBpfOffload: ");
+        pw.println(mEnableBpfOffload);
+
+        pw.print("enableLegacyDhcpServer: ");
+        pw.println(enableLegacyDhcpServer);
+
+        pw.print("enableWifiP2pDedicatedIp: ");
+        pw.println(mEnableWifiP2pDedicatedIp);
+
+        pw.print("mEnableSelectAllPrefixRange: ");
+        pw.println(mEnableSelectAllPrefixRange);
+    }
+
+    /** Returns the string representation of this object.*/
+    public String toString() {
+        final StringJoiner sj = new StringJoiner(" ");
+        sj.add(String.format("activeDataSubId:%d", activeDataSubId));
+        sj.add(String.format("tetherableUsbRegexs:%s", makeString(tetherableUsbRegexs)));
+        sj.add(String.format("tetherableWifiRegexs:%s", makeString(tetherableWifiRegexs)));
+        sj.add(String.format("tetherableWifiP2pRegexs:%s", makeString(tetherableWifiP2pRegexs)));
+        sj.add(String.format("tetherableBluetoothRegexs:%s",
+                makeString(tetherableBluetoothRegexs)));
+        sj.add(String.format("isDunRequired:%s", isDunRequired));
+        sj.add(String.format("chooseUpstreamAutomatically:%s", chooseUpstreamAutomatically));
+        sj.add(String.format("offloadPollInterval:%d", mOffloadPollInterval));
+        sj.add(String.format("preferredUpstreamIfaceTypes:%s",
+                toIntArray(preferredUpstreamIfaceTypes)));
+        sj.add(String.format("provisioningApp:%s", makeString(provisioningApp)));
+        sj.add(String.format("provisioningAppNoUi:%s", provisioningAppNoUi));
+        sj.add(String.format("enableBpfOffload:%s", mEnableBpfOffload));
+        sj.add(String.format("enableLegacyDhcpServer:%s", enableLegacyDhcpServer));
+        return String.format("TetheringConfiguration{%s}", sj.toString());
+    }
+
+    private static void dumpStringArray(PrintWriter pw, String label, String[] values) {
+        pw.print(label);
+        pw.print(": ");
+
+        if (values != null) {
+            final StringJoiner sj = new StringJoiner(", ", "[", "]");
+            for (String value : values) sj.add(value);
+            pw.print(sj.toString());
+        } else {
+            pw.print("null");
+        }
+
+        pw.println();
+    }
+
+    private static String makeString(String[] strings) {
+        if (strings == null) return "null";
+        final StringJoiner sj = new StringJoiner(",", "[", "]");
+        for (String s : strings) sj.add(s);
+        return sj.toString();
+    }
+
+    /** Check whether dun is required. */
+    public static boolean checkDunRequired(Context ctx) {
+        final TelephonyManager tm = (TelephonyManager) ctx.getSystemService(TELEPHONY_SERVICE);
+        // TelephonyManager would uses the active data subscription, which should be the one used
+        // by tethering.
+        return (tm != null) ? tm.isTetheringApnRequired() : false;
+    }
+
+    public int getOffloadPollInterval() {
+        return mOffloadPollInterval;
+    }
+
+    public boolean isBpfOffloadEnabled() {
+        return mEnableBpfOffload;
+    }
+
+    public boolean isSelectAllPrefixRangeEnabled() {
+        return mEnableSelectAllPrefixRange;
+    }
+
+    private static Collection<Integer> getUpstreamIfaceTypes(Resources res, boolean dunRequired) {
+        final int[] ifaceTypes = res.getIntArray(R.array.config_tether_upstream_types);
+        final ArrayList<Integer> upstreamIfaceTypes = new ArrayList<>(ifaceTypes.length);
+        for (int i : ifaceTypes) {
+            switch (i) {
+                case TYPE_MOBILE:
+                case TYPE_MOBILE_HIPRI:
+                    if (dunRequired) continue;
+                    break;
+                case TYPE_MOBILE_DUN:
+                    if (!dunRequired) continue;
+                    break;
+            }
+            upstreamIfaceTypes.add(i);
+        }
+
+        // Fix up upstream interface types for DUN or mobile. NOTE: independent
+        // of the value of |dunRequired|, cell data of one form or another is
+        // *always* an upstream, regardless of the upstream interface types
+        // specified by configuration resources.
+        if (dunRequired) {
+            appendIfNotPresent(upstreamIfaceTypes, TYPE_MOBILE_DUN);
+        } else {
+            // Do not modify if a cellular interface type is already present in the
+            // upstream interface types. Add TYPE_MOBILE and TYPE_MOBILE_HIPRI if no
+            // cellular interface types are found in the upstream interface types.
+            // This preserves backwards compatibility and prevents the DUN and default
+            // mobile types incorrectly appearing together, which could happen on
+            // previous releases in the common case where checkDunRequired returned
+            // DUN_UNSPECIFIED.
+            if (!containsOneOf(upstreamIfaceTypes, TYPE_MOBILE, TYPE_MOBILE_HIPRI)) {
+                upstreamIfaceTypes.add(TYPE_MOBILE);
+                upstreamIfaceTypes.add(TYPE_MOBILE_HIPRI);
+            }
+        }
+
+        // Always make sure our good friend Ethernet is present.
+        // TODO: consider unilaterally forcing this at the front.
+        prependIfNotPresent(upstreamIfaceTypes, TYPE_ETHERNET);
+
+        return upstreamIfaceTypes;
+    }
+
+    private static boolean matchesDownstreamRegexs(String iface, String[] regexs) {
+        for (String regex : regexs) {
+            if (iface.matches(regex)) return true;
+        }
+        return false;
+    }
+
+    private static String[] getLegacyDhcpRanges(Resources res) {
+        final String[] fromResource = getResourceStringArray(res, R.array.config_tether_dhcp_range);
+        if ((fromResource.length > 0) && (fromResource.length % 2 == 0)) {
+            return fromResource;
+        }
+        return copy(LEGACY_DHCP_DEFAULT_RANGE);
+    }
+
+    private static String getResourceString(Resources res, final int resId) {
+        try {
+            return res.getString(resId);
+        } catch (Resources.NotFoundException e) {
+            return "";
+        }
+    }
+
+    private static boolean getResourceBoolean(Resources res, int resId, boolean defaultValue) {
+        try {
+            return res.getBoolean(resId);
+        } catch (Resources.NotFoundException e404) {
+            return defaultValue;
+        }
+    }
+
+    private static String[] getResourceStringArray(Resources res, int resId) {
+        try {
+            final String[] strArray = res.getStringArray(resId);
+            return (strArray != null) ? strArray : EMPTY_STRING_ARRAY;
+        } catch (Resources.NotFoundException e404) {
+            return EMPTY_STRING_ARRAY;
+        }
+    }
+
+    private static int getResourceInteger(Resources res, int resId, int defaultValue) {
+        try {
+            return res.getInteger(resId);
+        } catch (Resources.NotFoundException e404) {
+            return defaultValue;
+        }
+    }
+
+    private boolean getEnableBpfOffload(final Resources res) {
+        // Get BPF offload config
+        // Priority 1: Device config
+        // Priority 2: Resource config
+        // Priority 3: Default value
+        final boolean defaultValue = getResourceBoolean(
+                res, R.bool.config_tether_enable_bpf_offload, true /** default value */);
+
+        return getDeviceConfigBoolean(OVERRIDE_TETHER_ENABLE_BPF_OFFLOAD, defaultValue);
+    }
+
+    private boolean getEnableLegacyDhcpServer(final Resources res) {
+        return getResourceBoolean(
+                res, R.bool.config_tether_enable_legacy_dhcp_server, false /** defaultValue */)
+                || getDeviceConfigBoolean(
+                TETHER_ENABLE_LEGACY_DHCP_SERVER, false /** defaultValue */);
+    }
+
+    private boolean getDeviceConfigBoolean(final String name, final boolean defaultValue) {
+        // Due to the limitation of static mock for testing, using #getDeviceConfigProperty instead
+        // of DeviceConfig#getBoolean. If using #getBoolean here, the test can't know that the
+        // returned boolean value comes from device config or default value (because of null
+        // property string). See the test case testBpfOffload{*} in TetheringConfigurationTest.java.
+        final String value = getDeviceConfigProperty(name);
+        return value != null ? Boolean.parseBoolean(value) : defaultValue;
+    }
+
+    @VisibleForTesting
+    protected String getDeviceConfigProperty(String name) {
+        return DeviceConfig.getProperty(NAMESPACE_CONNECTIVITY, name);
+    }
+
+    private Resources getResources(Context ctx, int subId) {
+        if (subId != SubscriptionManager.INVALID_SUBSCRIPTION_ID) {
+            return getResourcesForSubIdWrapper(ctx, subId);
+        } else {
+            return ctx.getResources();
+        }
+    }
+
+    @VisibleForTesting
+    protected Resources getResourcesForSubIdWrapper(Context ctx, int subId) {
+        return SubscriptionManager.getResourcesForSubId(ctx, subId);
+    }
+
+    private static String[] copy(String[] strarray) {
+        return Arrays.copyOf(strarray, strarray.length);
+    }
+
+    private static void prependIfNotPresent(ArrayList<Integer> list, int value) {
+        if (list.contains(value)) return;
+        list.add(0, value);
+    }
+
+    private static void appendIfNotPresent(ArrayList<Integer> list, int value) {
+        if (list.contains(value)) return;
+        list.add(value);
+    }
+
+    private static boolean containsOneOf(ArrayList<Integer> list, Integer... values) {
+        for (Integer value : values) {
+            if (list.contains(value)) return true;
+        }
+        return false;
+    }
+
+    private static int[] toIntArray(Collection<Integer> values) {
+        final int[] result = new int[values.size()];
+        int index = 0;
+        for (Integer value : values) {
+            result[index++] = value;
+        }
+        return result;
+    }
+
+    /**
+     * Convert this TetheringConfiguration to a TetheringConfigurationParcel.
+     */
+    public TetheringConfigurationParcel toStableParcelable() {
+        final TetheringConfigurationParcel parcel = new TetheringConfigurationParcel();
+        parcel.subId = activeDataSubId;
+        parcel.tetherableUsbRegexs = tetherableUsbRegexs;
+        parcel.tetherableWifiRegexs = tetherableWifiRegexs;
+        parcel.tetherableBluetoothRegexs = tetherableBluetoothRegexs;
+        parcel.isDunRequired = isDunRequired;
+        parcel.chooseUpstreamAutomatically = chooseUpstreamAutomatically;
+
+        parcel.preferredUpstreamIfaceTypes = toIntArray(preferredUpstreamIfaceTypes);
+
+        parcel.legacyDhcpRanges = legacyDhcpRanges;
+        parcel.defaultIPv4DNS = defaultIPv4DNS;
+        parcel.enableLegacyDhcpServer = enableLegacyDhcpServer;
+        parcel.provisioningApp = provisioningApp;
+        parcel.provisioningAppNoUi = provisioningAppNoUi;
+        parcel.provisioningCheckPeriod = provisioningCheckPeriod;
+        return parcel;
+    }
+}
diff --git a/Tethering/src/com/android/networkstack/tethering/TetheringDependencies.java b/Tethering/src/com/android/networkstack/tethering/TetheringDependencies.java
new file mode 100644
index 0000000..45b9141
--- /dev/null
+++ b/Tethering/src/com/android/networkstack/tethering/TetheringDependencies.java
@@ -0,0 +1,167 @@
+/*
+ * Copyright (C) 2017 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.android.networkstack.tethering;
+
+import android.app.usage.NetworkStatsManager;
+import android.bluetooth.BluetoothAdapter;
+import android.content.Context;
+import android.net.INetd;
+import android.net.NetworkRequest;
+import android.net.ip.IpServer;
+import android.net.util.SharedLog;
+import android.os.Handler;
+import android.os.IBinder;
+import android.os.Looper;
+import android.os.SystemProperties;
+import android.text.TextUtils;
+
+import androidx.annotation.NonNull;
+
+import com.android.internal.util.StateMachine;
+
+import java.util.ArrayList;
+
+
+/**
+ * Capture tethering dependencies, for injection.
+ *
+ * @hide
+ */
+public abstract class TetheringDependencies {
+    /**
+     * Get a reference to the BpfCoordinator to be used by tethering.
+     */
+    public @NonNull BpfCoordinator getBpfCoordinator(
+            @NonNull BpfCoordinator.Dependencies deps) {
+        return new BpfCoordinator(deps);
+    }
+
+    /**
+     * Get a reference to the offload hardware interface to be used by tethering.
+     */
+    public OffloadHardwareInterface getOffloadHardwareInterface(Handler h, SharedLog log) {
+        return new OffloadHardwareInterface(h, log);
+    }
+
+    /**
+     * Get a reference to the offload controller to be used by tethering.
+     */
+    @NonNull
+    public OffloadController getOffloadController(@NonNull Handler h,
+            @NonNull SharedLog log, @NonNull OffloadController.Dependencies deps) {
+        final NetworkStatsManager statsManager =
+                (NetworkStatsManager) getContext().getSystemService(Context.NETWORK_STATS_SERVICE);
+        return new OffloadController(h, getOffloadHardwareInterface(h, log),
+                getContext().getContentResolver(), statsManager, log, deps);
+    }
+
+
+    /**
+     * Get a reference to the UpstreamNetworkMonitor to be used by tethering.
+     */
+    public UpstreamNetworkMonitor getUpstreamNetworkMonitor(Context ctx, StateMachine target,
+            SharedLog log, int what) {
+        return new UpstreamNetworkMonitor(ctx, target, log, what);
+    }
+
+    /**
+     * Get a reference to the IPv6TetheringCoordinator to be used by tethering.
+     */
+    public IPv6TetheringCoordinator getIPv6TetheringCoordinator(
+            ArrayList<IpServer> notifyList, SharedLog log) {
+        return new IPv6TetheringCoordinator(notifyList, log);
+    }
+
+    /**
+     * Get dependencies to be used by IpServer.
+     */
+    public abstract IpServer.Dependencies getIpServerDependencies();
+
+    /**
+     * Indicates whether tethering is supported on the device.
+     */
+    public boolean isTetheringSupported() {
+        return true;
+    }
+
+    /**
+     * Get the NetworkRequest that should be fulfilled by the default network.
+     */
+    public abstract NetworkRequest getDefaultNetworkRequest();
+
+    /**
+     * Get a reference to the EntitlementManager to be used by tethering.
+     */
+    public EntitlementManager getEntitlementManager(Context ctx, Handler h, SharedLog log,
+            Runnable callback) {
+        return new EntitlementManager(ctx, h, log, callback);
+    }
+
+    /**
+     * Generate a new TetheringConfiguration according to input sub Id.
+     */
+    public TetheringConfiguration generateTetheringConfiguration(Context ctx, SharedLog log,
+            int subId) {
+        return new TetheringConfiguration(ctx, log, subId);
+    }
+
+    /**
+     * Get a reference to INetd to be used by tethering.
+     */
+    public INetd getINetd(Context context) {
+        return INetd.Stub.asInterface(
+                (IBinder) context.getSystemService(Context.NETD_SERVICE));
+    }
+
+    /**
+     * Get a reference to the TetheringNotificationUpdater to be used by tethering.
+     */
+    public TetheringNotificationUpdater getNotificationUpdater(@NonNull final Context ctx,
+            @NonNull final Looper looper) {
+        return new TetheringNotificationUpdater(ctx, looper);
+    }
+
+    /**
+     * Get tethering thread looper.
+     */
+    public abstract Looper getTetheringLooper();
+
+    /**
+     *  Get Context of TetheringSerice.
+     */
+    public abstract Context getContext();
+
+    /**
+     * Get a reference to BluetoothAdapter to be used by tethering.
+     */
+    public abstract BluetoothAdapter getBluetoothAdapter();
+
+    /**
+     * Get SystemProperties which indicate whether tethering is denied.
+     */
+    public boolean isTetheringDenied() {
+        return TextUtils.equals(SystemProperties.get("ro.tether.denied"), "true");
+    }
+
+    /**
+     * Get a reference to PrivateAddressCoordinator to be used by Tethering.
+     */
+    public PrivateAddressCoordinator getPrivateAddressCoordinator(Context ctx,
+            TetheringConfiguration cfg) {
+        return new PrivateAddressCoordinator(ctx, cfg);
+    }
+}
diff --git a/Tethering/src/com/android/networkstack/tethering/TetheringInterfaceUtils.java b/Tethering/src/com/android/networkstack/tethering/TetheringInterfaceUtils.java
new file mode 100644
index 0000000..ff38f71
--- /dev/null
+++ b/Tethering/src/com/android/networkstack/tethering/TetheringInterfaceUtils.java
@@ -0,0 +1,102 @@
+/*
+ * Copyright (C) 2018 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.android.networkstack.tethering;
+
+import android.annotation.Nullable;
+import android.net.LinkProperties;
+import android.net.NetworkCapabilities;
+import android.net.RouteInfo;
+import android.net.util.InterfaceSet;
+
+import com.android.net.module.util.NetUtils;
+
+import java.net.InetAddress;
+import java.net.UnknownHostException;
+
+/**
+ * @hide
+ */
+public final class TetheringInterfaceUtils {
+    private static final InetAddress IN6ADDR_ANY = getByAddress(
+            new byte[] {0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0});
+    private static final InetAddress INADDR_ANY = getByAddress(new byte[] {0, 0, 0, 0});
+
+    /**
+     * Get upstream interfaces for tethering based on default routes for IPv4/IPv6.
+     * @return null if there is no usable interface, or a set of at least one interface otherwise.
+     */
+    public static @Nullable InterfaceSet getTetheringInterfaces(UpstreamNetworkState ns) {
+        if (ns == null) {
+            return null;
+        }
+
+        final LinkProperties lp = ns.linkProperties;
+        final String if4 = getInterfaceForDestination(lp, INADDR_ANY);
+        final String if6 = getIPv6Interface(ns);
+
+        return (if4 == null && if6 == null) ? null : new InterfaceSet(if4, if6);
+    }
+
+    /**
+     * Get the upstream interface for IPv6 tethering.
+     * @return null if there is no usable interface, or the interface name otherwise.
+     */
+    public static @Nullable String getIPv6Interface(UpstreamNetworkState ns) {
+        // Broadly speaking:
+        //
+        //     [1] does the upstream have an IPv6 default route?
+        //
+        // and
+        //
+        //     [2] does the upstream have one or more global IPv6 /64s
+        //         dedicated to this device?
+        //
+        // In lieu of Prefix Delegation and other evaluation of whether a
+        // prefix may or may not be dedicated to this device, for now just
+        // check whether the upstream is TRANSPORT_CELLULAR. This works
+        // because "[t]he 3GPP network allocates each default bearer a unique
+        // /64 prefix", per RFC 6459, Section 5.2.
+        final boolean canTether =
+                (ns != null) && (ns.network != null)
+                && (ns.linkProperties != null) && (ns.networkCapabilities != null)
+                // At least one upstream DNS server:
+                && ns.linkProperties.hasIpv6DnsServer()
+                // Minimal amount of IPv6 provisioning:
+                && ns.linkProperties.hasGlobalIpv6Address()
+                // Temporary approximation of "dedicated prefix":
+                && ns.networkCapabilities.hasTransport(NetworkCapabilities.TRANSPORT_CELLULAR);
+
+        return canTether
+                ? getInterfaceForDestination(ns.linkProperties, IN6ADDR_ANY)
+                : null;
+    }
+
+    private static String getInterfaceForDestination(LinkProperties lp, InetAddress dst) {
+        final RouteInfo ri = (lp != null)
+                ? NetUtils.selectBestRoute(lp.getAllRoutes(), dst)
+                : null;
+        return (ri != null) ? ri.getInterface() : null;
+    }
+
+    private static InetAddress getByAddress(final byte[] addr) {
+        try {
+            return InetAddress.getByAddress(null, addr);
+        } catch (UnknownHostException e) {
+            throw new AssertionError("illegal address length" + addr.length);
+        }
+    }
+}
diff --git a/Tethering/src/com/android/networkstack/tethering/TetheringNotificationUpdater.java b/Tethering/src/com/android/networkstack/tethering/TetheringNotificationUpdater.java
new file mode 100644
index 0000000..a0198cc
--- /dev/null
+++ b/Tethering/src/com/android/networkstack/tethering/TetheringNotificationUpdater.java
@@ -0,0 +1,362 @@
+/*
+ * Copyright (C) 2020 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.android.networkstack.tethering;
+
+import static android.net.NetworkCapabilities.NET_CAPABILITY_NOT_ROAMING;
+import static android.text.TextUtils.isEmpty;
+
+import android.app.Notification;
+import android.app.Notification.Action;
+import android.app.NotificationChannel;
+import android.app.NotificationManager;
+import android.app.PendingIntent;
+import android.content.ComponentName;
+import android.content.Context;
+import android.content.Intent;
+import android.content.pm.PackageManager;
+import android.content.res.Configuration;
+import android.content.res.Resources;
+import android.net.NetworkCapabilities;
+import android.os.Handler;
+import android.os.Looper;
+import android.os.Message;
+import android.os.UserHandle;
+import android.provider.Settings;
+import android.telephony.SubscriptionManager;
+import android.telephony.TelephonyManager;
+import android.util.SparseArray;
+
+import androidx.annotation.DrawableRes;
+import androidx.annotation.IntDef;
+import androidx.annotation.IntRange;
+import androidx.annotation.NonNull;
+import androidx.annotation.Nullable;
+
+import com.android.internal.annotations.VisibleForTesting;
+
+import java.lang.annotation.Retention;
+import java.lang.annotation.RetentionPolicy;
+
+/**
+ * A class to display tethering-related notifications.
+ *
+ * <p>This class is not thread safe, it is intended to be used only from the tethering handler
+ * thread. However the constructor is an exception, as it is called on another thread ;
+ * therefore for thread safety all members of this class MUST either be final or initialized
+ * to their default value (0, false or null).
+ *
+ * @hide
+ */
+public class TetheringNotificationUpdater {
+    private static final String TAG = TetheringNotificationUpdater.class.getSimpleName();
+    private static final String CHANNEL_ID = "TETHERING_STATUS";
+    private static final String WIFI_DOWNSTREAM = "WIFI";
+    private static final String USB_DOWNSTREAM = "USB";
+    private static final String BLUETOOTH_DOWNSTREAM = "BT";
+    @VisibleForTesting
+    static final String ACTION_DISABLE_TETHERING =
+            "com.android.server.connectivity.tethering.DISABLE_TETHERING";
+    private static final boolean NOTIFY_DONE = true;
+    private static final boolean NO_NOTIFY = false;
+    @VisibleForTesting
+    static final int EVENT_SHOW_NO_UPSTREAM = 1;
+    // Id to update and cancel restricted notification. Must be unique within the tethering app.
+    @VisibleForTesting
+    static final int RESTRICTED_NOTIFICATION_ID = 1001;
+    // Id to update and cancel no upstream notification. Must be unique within the tethering app.
+    @VisibleForTesting
+    static final int NO_UPSTREAM_NOTIFICATION_ID = 1002;
+    // Id to update and cancel roaming notification. Must be unique within the tethering app.
+    @VisibleForTesting
+    static final int ROAMING_NOTIFICATION_ID = 1003;
+    @VisibleForTesting
+    static final int NO_ICON_ID = 0;
+    @VisibleForTesting
+    static final int DOWNSTREAM_NONE = 0;
+    // Refer to TelephonyManager#getSimCarrierId for more details about carrier id.
+    @VisibleForTesting
+    static final int VERIZON_CARRIER_ID = 1839;
+    private final Context mContext;
+    private final NotificationManager mNotificationManager;
+    private final NotificationChannel mChannel;
+    private final Handler mHandler;
+
+    // WARNING : the constructor is called on a different thread. Thread safety therefore
+    // relies on these values being initialized to 0, false or null, and not any other value. If you
+    // need to change this, you will need to change the thread where the constructor is invoked, or
+    // to introduce synchronization.
+    // Downstream type is one of ConnectivityManager.TETHERING_* constants, 0 1 or 2.
+    // This value has to be made 1 2 and 4, and OR'd with the others.
+    private int mDownstreamTypesMask = DOWNSTREAM_NONE;
+    private boolean mNoUpstream = false;
+    private boolean mRoaming = false;
+
+    // WARNING : this value is not able to being initialized to 0 and must have volatile because
+    // telephony service is not guaranteed that is up before tethering service starts. If telephony
+    // is up later than tethering, TetheringNotificationUpdater will use incorrect and valid
+    // subscription id(0) to query resources. Therefore, initialized subscription id must be
+    // INVALID_SUBSCRIPTION_ID.
+    private volatile int mActiveDataSubId = SubscriptionManager.INVALID_SUBSCRIPTION_ID;
+
+    @Retention(RetentionPolicy.SOURCE)
+    @IntDef(value = {
+            RESTRICTED_NOTIFICATION_ID,
+            NO_UPSTREAM_NOTIFICATION_ID,
+            ROAMING_NOTIFICATION_ID
+    })
+    @interface NotificationId {}
+
+    private static final class MccMncOverrideInfo {
+        public final String visitedMccMnc;
+        public final int homeMcc;
+        public final int homeMnc;
+        MccMncOverrideInfo(String visitedMccMnc, int mcc, int mnc) {
+            this.visitedMccMnc = visitedMccMnc;
+            this.homeMcc = mcc;
+            this.homeMnc = mnc;
+        }
+    }
+
+    private static final SparseArray<MccMncOverrideInfo> sCarrierIdToMccMnc = new SparseArray<>();
+
+    static {
+        sCarrierIdToMccMnc.put(VERIZON_CARRIER_ID, new MccMncOverrideInfo("20404", 311, 480));
+    }
+
+    public TetheringNotificationUpdater(@NonNull final Context context,
+            @NonNull final Looper looper) {
+        mContext = context;
+        mNotificationManager = (NotificationManager) context.createContextAsUser(UserHandle.ALL, 0)
+                .getSystemService(Context.NOTIFICATION_SERVICE);
+        mChannel = new NotificationChannel(
+                CHANNEL_ID,
+                context.getResources().getString(R.string.notification_channel_tethering_status),
+                NotificationManager.IMPORTANCE_LOW);
+        mNotificationManager.createNotificationChannel(mChannel);
+        mHandler = new NotificationHandler(looper);
+    }
+
+    private class NotificationHandler extends Handler {
+        NotificationHandler(Looper looper) {
+            super(looper);
+        }
+
+        @Override
+        public void handleMessage(Message msg) {
+            switch(msg.what) {
+                case EVENT_SHOW_NO_UPSTREAM:
+                    notifyTetheringNoUpstream();
+                    break;
+            }
+        }
+    }
+
+    /** Called when downstream has changed */
+    public void onDownstreamChanged(@IntRange(from = 0, to = 7) final int downstreamTypesMask) {
+        updateActiveNotifications(
+                mActiveDataSubId, downstreamTypesMask, mNoUpstream, mRoaming);
+    }
+
+    /** Called when active data subscription id changed */
+    public void onActiveDataSubscriptionIdChanged(final int subId) {
+        updateActiveNotifications(subId, mDownstreamTypesMask, mNoUpstream, mRoaming);
+    }
+
+    /** Called when upstream network capabilities changed */
+    public void onUpstreamCapabilitiesChanged(@Nullable final NetworkCapabilities capabilities) {
+        final boolean isNoUpstream = (capabilities == null);
+        final boolean isRoaming = capabilities != null
+                && !capabilities.hasCapability(NET_CAPABILITY_NOT_ROAMING);
+        updateActiveNotifications(
+                mActiveDataSubId, mDownstreamTypesMask, isNoUpstream, isRoaming);
+    }
+
+    @NonNull
+    @VisibleForTesting
+    final Handler getHandler() {
+        return mHandler;
+    }
+
+    @NonNull
+    @VisibleForTesting
+    Resources getResourcesForSubId(@NonNull final Context context, final int subId) {
+        final Resources res = SubscriptionManager.getResourcesForSubId(context, subId);
+        final TelephonyManager tm =
+                ((TelephonyManager) context.getSystemService(Context.TELEPHONY_SERVICE))
+                        .createForSubscriptionId(mActiveDataSubId);
+        final int carrierId = tm.getSimCarrierId();
+        final String mccmnc = tm.getSimOperator();
+        final MccMncOverrideInfo overrideInfo = sCarrierIdToMccMnc.get(carrierId);
+        if (overrideInfo != null && overrideInfo.visitedMccMnc.equals(mccmnc)) {
+            // Re-configure MCC/MNC value to specific carrier to get right resources.
+            final Configuration config = res.getConfiguration();
+            config.mcc = overrideInfo.homeMcc;
+            config.mnc = overrideInfo.homeMnc;
+            return context.createConfigurationContext(config).getResources();
+        }
+        return res;
+    }
+
+    private void updateActiveNotifications(final int subId, final int downstreamTypes,
+            final boolean noUpstream, final boolean isRoaming) {
+        final boolean tetheringActiveChanged =
+                (downstreamTypes == DOWNSTREAM_NONE) != (mDownstreamTypesMask == DOWNSTREAM_NONE);
+        final boolean subIdChanged = subId != mActiveDataSubId;
+        final boolean upstreamChanged = noUpstream != mNoUpstream;
+        final boolean roamingChanged = isRoaming != mRoaming;
+        final boolean updateAll = tetheringActiveChanged || subIdChanged;
+        mActiveDataSubId = subId;
+        mDownstreamTypesMask = downstreamTypes;
+        mNoUpstream = noUpstream;
+        mRoaming = isRoaming;
+
+        if (updateAll || upstreamChanged) updateNoUpstreamNotification();
+        if (updateAll || roamingChanged) updateRoamingNotification();
+    }
+
+    private void updateNoUpstreamNotification() {
+        final boolean tetheringInactive = mDownstreamTypesMask == DOWNSTREAM_NONE;
+
+        if (tetheringInactive || !mNoUpstream || setupNoUpstreamNotification() == NO_NOTIFY) {
+            clearNotification(NO_UPSTREAM_NOTIFICATION_ID);
+            mHandler.removeMessages(EVENT_SHOW_NO_UPSTREAM);
+        }
+    }
+
+    private void updateRoamingNotification() {
+        final boolean tetheringInactive = mDownstreamTypesMask == DOWNSTREAM_NONE;
+
+        if (tetheringInactive || !mRoaming || setupRoamingNotification() == NO_NOTIFY) {
+            clearNotification(ROAMING_NOTIFICATION_ID);
+        }
+    }
+
+    @VisibleForTesting
+    void tetheringRestrictionLifted() {
+        clearNotification(RESTRICTED_NOTIFICATION_ID);
+    }
+
+    private void clearNotification(@NotificationId final int id) {
+        mNotificationManager.cancel(null /* tag */, id);
+    }
+
+    @VisibleForTesting
+    static String getSettingsPackageName(@NonNull final PackageManager pm) {
+        final Intent settingsIntent = new Intent(Settings.ACTION_SETTINGS);
+        final ComponentName settingsComponent = settingsIntent.resolveActivity(pm);
+        return settingsComponent != null
+                ? settingsComponent.getPackageName() : "com.android.settings";
+    }
+
+    @VisibleForTesting
+    void notifyTetheringDisabledByRestriction() {
+        final Resources res = getResourcesForSubId(mContext, mActiveDataSubId);
+        final String title = res.getString(R.string.disable_tether_notification_title);
+        final String message = res.getString(R.string.disable_tether_notification_message);
+        if (isEmpty(title) || isEmpty(message)) return;
+
+        final PendingIntent pi = PendingIntent.getActivity(
+                mContext.createContextAsUser(UserHandle.CURRENT, 0 /* flags */),
+                0 /* requestCode */,
+                new Intent(Settings.ACTION_TETHER_SETTINGS)
+                        .setPackage(getSettingsPackageName(mContext.getPackageManager()))
+                        .addFlags(Intent.FLAG_ACTIVITY_NEW_TASK),
+                PendingIntent.FLAG_IMMUTABLE,
+                null /* options */);
+
+        showNotification(R.drawable.stat_sys_tether_general, title, message,
+                RESTRICTED_NOTIFICATION_ID, false /* ongoing */, pi, new Action[0]);
+    }
+
+    private void notifyTetheringNoUpstream() {
+        final Resources res = getResourcesForSubId(mContext, mActiveDataSubId);
+        final String title = res.getString(R.string.no_upstream_notification_title);
+        final String message = res.getString(R.string.no_upstream_notification_message);
+        final String disableButton =
+                res.getString(R.string.no_upstream_notification_disable_button);
+        if (isEmpty(title) || isEmpty(message) || isEmpty(disableButton)) return;
+
+        final Intent intent = new Intent(ACTION_DISABLE_TETHERING);
+        intent.setPackage(mContext.getPackageName());
+        final PendingIntent pi = PendingIntent.getBroadcast(
+                mContext.createContextAsUser(UserHandle.CURRENT, 0 /* flags */),
+                0 /* requestCode */,
+                intent,
+                PendingIntent.FLAG_IMMUTABLE);
+        final Action action = new Action.Builder(NO_ICON_ID, disableButton, pi).build();
+
+        showNotification(R.drawable.stat_sys_tether_general, title, message,
+                NO_UPSTREAM_NOTIFICATION_ID, true /* ongoing */, null /* pendingIntent */, action);
+    }
+
+    private boolean setupRoamingNotification() {
+        final Resources res = getResourcesForSubId(mContext, mActiveDataSubId);
+        final boolean upstreamRoamingNotification =
+                res.getBoolean(R.bool.config_upstream_roaming_notification);
+
+        if (!upstreamRoamingNotification) return NO_NOTIFY;
+
+        final String title = res.getString(R.string.upstream_roaming_notification_title);
+        final String message = res.getString(R.string.upstream_roaming_notification_message);
+        if (isEmpty(title) || isEmpty(message)) return NO_NOTIFY;
+
+        final PendingIntent pi = PendingIntent.getActivity(
+                mContext.createContextAsUser(UserHandle.CURRENT, 0 /* flags */),
+                0 /* requestCode */,
+                new Intent(Settings.ACTION_TETHER_SETTINGS)
+                        .setPackage(getSettingsPackageName(mContext.getPackageManager()))
+                        .addFlags(Intent.FLAG_ACTIVITY_NEW_TASK),
+                PendingIntent.FLAG_IMMUTABLE,
+                null /* options */);
+
+        showNotification(R.drawable.stat_sys_tether_general, title, message,
+                ROAMING_NOTIFICATION_ID, true /* ongoing */, pi, new Action[0]);
+        return NOTIFY_DONE;
+    }
+
+    private boolean setupNoUpstreamNotification() {
+        final Resources res = getResourcesForSubId(mContext, mActiveDataSubId);
+        final int delayToShowUpstreamNotification =
+                res.getInteger(R.integer.delay_to_show_no_upstream_after_no_backhaul);
+
+        if (delayToShowUpstreamNotification < 0) return NO_NOTIFY;
+
+        mHandler.sendMessageDelayed(mHandler.obtainMessage(EVENT_SHOW_NO_UPSTREAM),
+                delayToShowUpstreamNotification);
+        return NOTIFY_DONE;
+    }
+
+    private void showNotification(@DrawableRes final int iconId, @NonNull final String title,
+            @NonNull final String message, @NotificationId final int id, final boolean ongoing,
+            @Nullable PendingIntent pi, @NonNull final Action... actions) {
+        final Notification notification =
+                new Notification.Builder(mContext, mChannel.getId())
+                        .setSmallIcon(iconId)
+                        .setContentTitle(title)
+                        .setContentText(message)
+                        .setOngoing(ongoing)
+                        .setColor(mContext.getColor(
+                                android.R.color.system_notification_accent_color))
+                        .setVisibility(Notification.VISIBILITY_PUBLIC)
+                        .setCategory(Notification.CATEGORY_STATUS)
+                        .setContentIntent(pi)
+                        .setActions(actions)
+                        .build();
+
+        mNotificationManager.notify(null /* tag */, id, notification);
+    }
+}
diff --git a/Tethering/src/com/android/networkstack/tethering/TetheringService.java b/Tethering/src/com/android/networkstack/tethering/TetheringService.java
new file mode 100644
index 0000000..613328d
--- /dev/null
+++ b/Tethering/src/com/android/networkstack/tethering/TetheringService.java
@@ -0,0 +1,389 @@
+/*
+ * Copyright (C) 2019 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.android.networkstack.tethering;
+
+import static android.Manifest.permission.ACCESS_NETWORK_STATE;
+import static android.Manifest.permission.NETWORK_STACK;
+import static android.Manifest.permission.TETHER_PRIVILEGED;
+import static android.content.pm.PackageManager.PERMISSION_GRANTED;
+import static android.net.NetworkStack.PERMISSION_MAINLINE_NETWORK_STACK;
+import static android.net.TetheringManager.TETHER_ERROR_NO_ACCESS_TETHERING_PERMISSION;
+import static android.net.TetheringManager.TETHER_ERROR_NO_CHANGE_TETHERING_PERMISSION;
+import static android.net.TetheringManager.TETHER_ERROR_NO_ERROR;
+import static android.net.TetheringManager.TETHER_ERROR_UNSUPPORTED;
+import static android.net.dhcp.IDhcpServer.STATUS_UNKNOWN_ERROR;
+
+import android.app.Service;
+import android.bluetooth.BluetoothAdapter;
+import android.content.Context;
+import android.content.Intent;
+import android.net.IIntResultListener;
+import android.net.INetworkStackConnector;
+import android.net.ITetheringConnector;
+import android.net.ITetheringEventCallback;
+import android.net.NetworkCapabilities;
+import android.net.NetworkRequest;
+import android.net.NetworkStack;
+import android.net.TetheringRequestParcel;
+import android.net.dhcp.DhcpServerCallbacks;
+import android.net.dhcp.DhcpServingParamsParcel;
+import android.net.ip.IpServer;
+import android.os.Binder;
+import android.os.HandlerThread;
+import android.os.IBinder;
+import android.os.Looper;
+import android.os.RemoteException;
+import android.os.ResultReceiver;
+import android.provider.Settings;
+import android.util.Log;
+
+import androidx.annotation.NonNull;
+import androidx.annotation.Nullable;
+
+import com.android.internal.annotations.VisibleForTesting;
+
+import java.io.FileDescriptor;
+import java.io.PrintWriter;
+
+/**
+ * Android service used to manage tethering.
+ *
+ * <p>The service returns a binder for the system server to communicate with the tethering.
+ */
+public class TetheringService extends Service {
+    private static final String TAG = TetheringService.class.getSimpleName();
+
+    private TetheringConnector mConnector;
+
+    @Override
+    public void onCreate() {
+        final TetheringDependencies deps = makeTetheringDependencies();
+        // The Tethering object needs a fully functional context to start, so this can't be done
+        // in the constructor.
+        mConnector = new TetheringConnector(makeTethering(deps), TetheringService.this);
+    }
+
+    /**
+     * Make a reference to Tethering object.
+     */
+    @VisibleForTesting
+    public Tethering makeTethering(TetheringDependencies deps) {
+        System.loadLibrary("tetherutilsjni");
+        return new Tethering(deps);
+    }
+
+    @NonNull
+    @Override
+    public IBinder onBind(Intent intent) {
+        return mConnector;
+    }
+
+    private static class TetheringConnector extends ITetheringConnector.Stub {
+        private final TetheringService mService;
+        private final Tethering mTethering;
+
+        TetheringConnector(Tethering tether, TetheringService service) {
+            mTethering = tether;
+            mService = service;
+        }
+
+        @Override
+        public void tether(String iface, String callerPkg, String callingAttributionTag,
+                IIntResultListener listener) {
+            if (checkAndNotifyCommonError(callerPkg, callingAttributionTag, listener)) return;
+
+            try {
+                listener.onResult(mTethering.tether(iface));
+            } catch (RemoteException e) { }
+        }
+
+        @Override
+        public void untether(String iface, String callerPkg, String callingAttributionTag,
+                IIntResultListener listener) {
+            if (checkAndNotifyCommonError(callerPkg, callingAttributionTag, listener)) return;
+
+            try {
+                listener.onResult(mTethering.untether(iface));
+            } catch (RemoteException e) { }
+        }
+
+        @Override
+        public void setUsbTethering(boolean enable, String callerPkg, String callingAttributionTag,
+                IIntResultListener listener) {
+            if (checkAndNotifyCommonError(callerPkg, callingAttributionTag, listener)) return;
+
+            try {
+                listener.onResult(mTethering.setUsbTethering(enable));
+            } catch (RemoteException e) { }
+        }
+
+        @Override
+        public void startTethering(TetheringRequestParcel request, String callerPkg,
+                String callingAttributionTag, IIntResultListener listener) {
+            if (checkAndNotifyCommonError(callerPkg,
+                    callingAttributionTag,
+                    request.exemptFromEntitlementCheck /* onlyAllowPrivileged */,
+                    listener)) {
+                return;
+            }
+
+            mTethering.startTethering(request, listener);
+        }
+
+        @Override
+        public void stopTethering(int type, String callerPkg, String callingAttributionTag,
+                IIntResultListener listener) {
+            if (checkAndNotifyCommonError(callerPkg, callingAttributionTag, listener)) return;
+
+            try {
+                mTethering.stopTethering(type);
+                listener.onResult(TETHER_ERROR_NO_ERROR);
+            } catch (RemoteException e) { }
+        }
+
+        @Override
+        public void requestLatestTetheringEntitlementResult(int type, ResultReceiver receiver,
+                boolean showEntitlementUi, String callerPkg, String callingAttributionTag) {
+            if (checkAndNotifyCommonError(callerPkg, callingAttributionTag, receiver)) return;
+
+            mTethering.requestLatestTetheringEntitlementResult(type, receiver, showEntitlementUi);
+        }
+
+        @Override
+        public void registerTetheringEventCallback(ITetheringEventCallback callback,
+                String callerPkg) {
+            try {
+                if (!hasTetherAccessPermission()) {
+                    callback.onCallbackStopped(TETHER_ERROR_NO_ACCESS_TETHERING_PERMISSION);
+                    return;
+                }
+                mTethering.registerTetheringEventCallback(callback);
+            } catch (RemoteException e) { }
+        }
+
+        @Override
+        public void unregisterTetheringEventCallback(ITetheringEventCallback callback,
+                String callerPkg) {
+            try {
+                if (!hasTetherAccessPermission()) {
+                    callback.onCallbackStopped(TETHER_ERROR_NO_ACCESS_TETHERING_PERMISSION);
+                    return;
+                }
+                mTethering.unregisterTetheringEventCallback(callback);
+            } catch (RemoteException e) { }
+        }
+
+        @Override
+        public void stopAllTethering(String callerPkg, String callingAttributionTag,
+                IIntResultListener listener) {
+            if (checkAndNotifyCommonError(callerPkg, callingAttributionTag, listener)) return;
+
+            try {
+                mTethering.untetherAll();
+                listener.onResult(TETHER_ERROR_NO_ERROR);
+            } catch (RemoteException e) { }
+        }
+
+        @Override
+        public void isTetheringSupported(String callerPkg, String callingAttributionTag,
+                IIntResultListener listener) {
+            if (checkAndNotifyCommonError(callerPkg, callingAttributionTag, listener)) return;
+
+            try {
+                listener.onResult(TETHER_ERROR_NO_ERROR);
+            } catch (RemoteException e) { }
+        }
+
+        @Override
+        protected void dump(@NonNull FileDescriptor fd, @NonNull PrintWriter writer,
+                    @Nullable String[] args) {
+            mTethering.dump(fd, writer, args);
+        }
+
+        private boolean checkAndNotifyCommonError(final String callerPkg,
+                final String callingAttributionTag, final IIntResultListener listener) {
+            return checkAndNotifyCommonError(callerPkg, callingAttributionTag,
+                    false /* onlyAllowPrivileged */, listener);
+        }
+
+        private boolean checkAndNotifyCommonError(final String callerPkg,
+                final String callingAttributionTag, final boolean onlyAllowPrivileged,
+                final IIntResultListener listener) {
+            try {
+                if (!hasTetherChangePermission(callerPkg, callingAttributionTag,
+                        onlyAllowPrivileged)) {
+                    listener.onResult(TETHER_ERROR_NO_CHANGE_TETHERING_PERMISSION);
+                    return true;
+                }
+                if (!mTethering.isTetheringSupported()) {
+                    listener.onResult(TETHER_ERROR_UNSUPPORTED);
+                    return true;
+                }
+            } catch (RemoteException e) {
+                return true;
+            }
+
+            return false;
+        }
+
+        private boolean checkAndNotifyCommonError(final String callerPkg,
+                final String callingAttributionTag, final ResultReceiver receiver) {
+            if (!hasTetherChangePermission(callerPkg, callingAttributionTag,
+                    false /* onlyAllowPrivileged */)) {
+                receiver.send(TETHER_ERROR_NO_CHANGE_TETHERING_PERMISSION, null);
+                return true;
+            }
+            if (!mTethering.isTetheringSupported()) {
+                receiver.send(TETHER_ERROR_UNSUPPORTED, null);
+                return true;
+            }
+
+            return false;
+        }
+
+        private boolean hasNetworkStackPermission() {
+            return checkCallingOrSelfPermission(NETWORK_STACK)
+                    || checkCallingOrSelfPermission(PERMISSION_MAINLINE_NETWORK_STACK);
+        }
+
+        private boolean hasTetherPrivilegedPermission() {
+            return checkCallingOrSelfPermission(TETHER_PRIVILEGED);
+        }
+
+        private boolean checkCallingOrSelfPermission(final String permission) {
+            return mService.checkCallingOrSelfPermission(permission) == PERMISSION_GRANTED;
+        }
+
+        private boolean hasTetherChangePermission(final String callerPkg,
+                final String callingAttributionTag, final boolean onlyAllowPrivileged) {
+            if (onlyAllowPrivileged && !hasNetworkStackPermission()) return false;
+
+            if (hasTetherPrivilegedPermission()) return true;
+
+            if (mTethering.isTetherProvisioningRequired()) return false;
+
+            int uid = Binder.getCallingUid();
+
+            // If callerPkg's uid is not same as Binder.getCallingUid(),
+            // checkAndNoteWriteSettingsOperation will return false and the operation will be
+            // denied.
+            return mService.checkAndNoteWriteSettingsOperation(mService, uid, callerPkg,
+                    callingAttributionTag, false /* throwException */);
+        }
+
+        private boolean hasTetherAccessPermission() {
+            if (hasTetherPrivilegedPermission()) return true;
+
+            return mService.checkCallingOrSelfPermission(
+                    ACCESS_NETWORK_STATE) == PERMISSION_GRANTED;
+        }
+    }
+
+    /**
+     * Check if the package is a allowed to write settings. This also accounts that such an access
+     * happened.
+     *
+     * @return {@code true} iff the package is allowed to write settings.
+     */
+    @VisibleForTesting
+    boolean checkAndNoteWriteSettingsOperation(@NonNull Context context, int uid,
+            @NonNull String callingPackage, @Nullable String callingAttributionTag,
+            boolean throwException) {
+        return Settings.checkAndNoteWriteSettingsOperation(context, uid, callingPackage,
+                throwException);
+    }
+
+    /**
+     * An injection method for testing.
+     */
+    @VisibleForTesting
+    public TetheringDependencies makeTetheringDependencies() {
+        return new TetheringDependencies() {
+            @Override
+            public NetworkRequest getDefaultNetworkRequest() {
+                // TODO: b/147280869, add a proper system API to replace this.
+                final NetworkRequest trackDefaultRequest = new NetworkRequest.Builder()
+                        .clearCapabilities()
+                        .addCapability(NetworkCapabilities.NET_CAPABILITY_NOT_RESTRICTED)
+                        .addCapability(NetworkCapabilities.NET_CAPABILITY_TRUSTED)
+                        .addCapability(NetworkCapabilities.NET_CAPABILITY_NOT_VPN)
+                        .addCapability(NetworkCapabilities.NET_CAPABILITY_INTERNET)
+                        .build();
+                return trackDefaultRequest;
+            }
+
+            @Override
+            public Looper getTetheringLooper() {
+                final HandlerThread tetherThread = new HandlerThread("android.tethering");
+                tetherThread.start();
+                return tetherThread.getLooper();
+            }
+
+            @Override
+            public Context getContext() {
+                return TetheringService.this;
+            }
+
+            @Override
+            public IpServer.Dependencies getIpServerDependencies() {
+                return new IpServer.Dependencies() {
+                    @Override
+                    public void makeDhcpServer(String ifName, DhcpServingParamsParcel params,
+                            DhcpServerCallbacks cb) {
+                        try {
+                            final INetworkStackConnector service = getNetworkStackConnector();
+                            if (service == null) return;
+
+                            service.makeDhcpServer(ifName, params, cb);
+                        } catch (RemoteException e) {
+                            Log.e(TAG, "Fail to make dhcp server");
+                            try {
+                                cb.onDhcpServerCreated(STATUS_UNKNOWN_ERROR, null);
+                            } catch (RemoteException re) { }
+                        }
+                    }
+                };
+            }
+
+            // TODO: replace this by NetworkStackClient#getRemoteConnector after refactoring
+            // networkStackClient.
+            static final int NETWORKSTACK_TIMEOUT_MS = 60_000;
+            private INetworkStackConnector getNetworkStackConnector() {
+                IBinder connector;
+                try {
+                    final long before = System.currentTimeMillis();
+                    while ((connector = NetworkStack.getService()) == null) {
+                        if (System.currentTimeMillis() - before > NETWORKSTACK_TIMEOUT_MS) {
+                            Log.wtf(TAG, "Timeout, fail to get INetworkStackConnector");
+                            return null;
+                        }
+                        Thread.sleep(200);
+                    }
+                } catch (InterruptedException e) {
+                    Log.wtf(TAG, "Interrupted, fail to get INetworkStackConnector");
+                    return null;
+                }
+                return INetworkStackConnector.Stub.asInterface(connector);
+            }
+
+            @Override
+            public BluetoothAdapter getBluetoothAdapter() {
+                return BluetoothAdapter.getDefaultAdapter();
+            }
+        };
+    }
+}
diff --git a/Tethering/src/com/android/networkstack/tethering/UpstreamNetworkMonitor.java b/Tethering/src/com/android/networkstack/tethering/UpstreamNetworkMonitor.java
new file mode 100644
index 0000000..b17065c
--- /dev/null
+++ b/Tethering/src/com/android/networkstack/tethering/UpstreamNetworkMonitor.java
@@ -0,0 +1,607 @@
+/*
+ * Copyright (C) 2017 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.android.networkstack.tethering;
+
+import static android.net.ConnectivityManager.TYPE_BLUETOOTH;
+import static android.net.ConnectivityManager.TYPE_ETHERNET;
+import static android.net.ConnectivityManager.TYPE_MOBILE;
+import static android.net.ConnectivityManager.TYPE_MOBILE_DUN;
+import static android.net.ConnectivityManager.TYPE_MOBILE_HIPRI;
+import static android.net.ConnectivityManager.TYPE_WIFI;
+import static android.net.NetworkCapabilities.NET_CAPABILITY_DUN;
+import static android.net.NetworkCapabilities.NET_CAPABILITY_INTERNET;
+import static android.net.NetworkCapabilities.NET_CAPABILITY_NOT_RESTRICTED;
+import static android.net.NetworkCapabilities.NET_CAPABILITY_NOT_VPN;
+import static android.net.NetworkCapabilities.TRANSPORT_CELLULAR;
+
+import android.content.Context;
+import android.net.ConnectivityManager;
+import android.net.ConnectivityManager.NetworkCallback;
+import android.net.IpPrefix;
+import android.net.LinkProperties;
+import android.net.Network;
+import android.net.NetworkCapabilities;
+import android.net.NetworkRequest;
+import android.net.util.PrefixUtils;
+import android.net.util.SharedLog;
+import android.os.Handler;
+import android.util.Log;
+import android.util.SparseIntArray;
+
+import com.android.internal.annotations.VisibleForTesting;
+import com.android.internal.util.StateMachine;
+
+import java.util.HashMap;
+import java.util.HashSet;
+import java.util.Set;
+
+
+/**
+ * A class to centralize all the network and link properties information
+ * pertaining to the current and any potential upstream network.
+ *
+ * The owner of UNM gets it to register network callbacks by calling the
+ * following methods :
+ * Calling #startTrackDefaultNetwork() to track the system default network.
+ * Calling #startObserveAllNetworks() to observe all networks. Listening all
+ * networks is necessary while the expression of preferred upstreams remains
+ * a list of legacy connectivity types.  In future, this can be revisited.
+ * Calling #registerMobileNetworkRequest() to bring up mobile DUN/HIPRI network.
+ *
+ * The methods and data members of this class are only to be accessed and
+ * modified from the tethering main state machine thread. Any other
+ * access semantics would necessitate the addition of locking.
+ *
+ * TODO: Move upstream selection logic here.
+ *
+ * All callback methods are run on the same thread as the specified target
+ * state machine.  This class does not require locking when accessed from this
+ * thread.  Access from other threads is not advised.
+ *
+ * @hide
+ */
+public class UpstreamNetworkMonitor {
+    private static final String TAG = UpstreamNetworkMonitor.class.getSimpleName();
+    private static final boolean DBG = false;
+    private static final boolean VDBG = false;
+
+    public static final int EVENT_ON_CAPABILITIES   = 1;
+    public static final int EVENT_ON_LINKPROPERTIES = 2;
+    public static final int EVENT_ON_LOST           = 3;
+    public static final int NOTIFY_LOCAL_PREFIXES   = 10;
+    // This value is used by deprecated preferredUpstreamIfaceTypes selection which is default
+    // disabled.
+    @VisibleForTesting
+    public static final int TYPE_NONE = -1;
+
+    private static final int CALLBACK_LISTEN_ALL = 1;
+    private static final int CALLBACK_DEFAULT_INTERNET = 2;
+    private static final int CALLBACK_MOBILE_REQUEST = 3;
+
+    private static final SparseIntArray sLegacyTypeToTransport = new SparseIntArray();
+    static {
+        sLegacyTypeToTransport.put(TYPE_MOBILE,       NetworkCapabilities.TRANSPORT_CELLULAR);
+        sLegacyTypeToTransport.put(TYPE_MOBILE_DUN,   NetworkCapabilities.TRANSPORT_CELLULAR);
+        sLegacyTypeToTransport.put(TYPE_MOBILE_HIPRI, NetworkCapabilities.TRANSPORT_CELLULAR);
+        sLegacyTypeToTransport.put(TYPE_WIFI,         NetworkCapabilities.TRANSPORT_WIFI);
+        sLegacyTypeToTransport.put(TYPE_BLUETOOTH,    NetworkCapabilities.TRANSPORT_BLUETOOTH);
+        sLegacyTypeToTransport.put(TYPE_ETHERNET,     NetworkCapabilities.TRANSPORT_ETHERNET);
+    }
+
+    private final Context mContext;
+    private final SharedLog mLog;
+    private final StateMachine mTarget;
+    private final Handler mHandler;
+    private final int mWhat;
+    private final HashMap<Network, UpstreamNetworkState> mNetworkMap = new HashMap<>();
+    private HashSet<IpPrefix> mLocalPrefixes;
+    private ConnectivityManager mCM;
+    private EntitlementManager mEntitlementMgr;
+    private NetworkCallback mListenAllCallback;
+    private NetworkCallback mDefaultNetworkCallback;
+    private NetworkCallback mMobileNetworkCallback;
+    private boolean mDunRequired;
+    // Whether the current default upstream is mobile or not.
+    private boolean mIsDefaultCellularUpstream;
+    // The current system default network (not really used yet).
+    private Network mDefaultInternetNetwork;
+    // The current upstream network used for tethering.
+    private Network mTetheringUpstreamNetwork;
+
+    public UpstreamNetworkMonitor(Context ctx, StateMachine tgt, SharedLog log, int what) {
+        mContext = ctx;
+        mTarget = tgt;
+        mHandler = mTarget.getHandler();
+        mLog = log.forSubComponent(TAG);
+        mWhat = what;
+        mLocalPrefixes = new HashSet<>();
+        mIsDefaultCellularUpstream = false;
+    }
+
+    @VisibleForTesting
+    public UpstreamNetworkMonitor(
+            ConnectivityManager cm, StateMachine tgt, SharedLog log, int what) {
+        this((Context) null, tgt, log, what);
+        mCM = cm;
+    }
+
+    /**
+     * Tracking the system default network. This method should be called when system is ready.
+     *
+     * @param defaultNetworkRequest should be the same as ConnectivityService default request
+     * @param entitle a EntitlementManager object to communicate between EntitlementManager and
+     * UpstreamNetworkMonitor
+     */
+    public void startTrackDefaultNetwork(NetworkRequest defaultNetworkRequest,
+            EntitlementManager entitle) {
+
+        // defaultNetworkRequest is not really a "request", just a way of tracking the system
+        // default network. It's guaranteed not to actually bring up any networks because it's
+        // the should be the same request as the ConnectivityService default request, and thus
+        // shares fate with it. We can't use registerDefaultNetworkCallback because it will not
+        // track the system default network if there is a VPN that applies to our UID.
+        if (mDefaultNetworkCallback == null) {
+            mDefaultNetworkCallback = new UpstreamNetworkCallback(CALLBACK_DEFAULT_INTERNET);
+            cm().requestNetwork(defaultNetworkRequest, mDefaultNetworkCallback, mHandler);
+        }
+        if (mEntitlementMgr == null) {
+            mEntitlementMgr = entitle;
+        }
+    }
+
+    /** Listen all networks. */
+    public void startObserveAllNetworks() {
+        stop();
+
+        final NetworkRequest listenAllRequest = new NetworkRequest.Builder()
+                .clearCapabilities().build();
+        mListenAllCallback = new UpstreamNetworkCallback(CALLBACK_LISTEN_ALL);
+        cm().registerNetworkCallback(listenAllRequest, mListenAllCallback, mHandler);
+    }
+
+    /**
+     * Stop tracking candidate tethering upstreams and release mobile network request.
+     * Note: this function is used when tethering is stopped because tethering do not need to
+     * choose upstream anymore. But it would not stop default network tracking because
+     * EntitlementManager may need to know default network to decide whether to request entitlement
+     * check even tethering is not active yet.
+     */
+    public void stop() {
+        releaseMobileNetworkRequest();
+
+        releaseCallback(mListenAllCallback);
+        mListenAllCallback = null;
+
+        mTetheringUpstreamNetwork = null;
+        mNetworkMap.clear();
+    }
+
+    /** Setup or teardown DUN connection according to |dunRequired|. */
+    public void updateMobileRequiresDun(boolean dunRequired) {
+        final boolean valueChanged = (mDunRequired != dunRequired);
+        mDunRequired = dunRequired;
+        if (valueChanged && mobileNetworkRequested()) {
+            releaseMobileNetworkRequest();
+            registerMobileNetworkRequest();
+        }
+    }
+
+    /** Whether mobile network is requested. */
+    public boolean mobileNetworkRequested() {
+        return (mMobileNetworkCallback != null);
+    }
+
+    /** Request mobile network if mobile upstream is permitted. */
+    public void registerMobileNetworkRequest() {
+        if (!isCellularUpstreamPermitted()) {
+            mLog.i("registerMobileNetworkRequest() is not permitted");
+            releaseMobileNetworkRequest();
+            return;
+        }
+        if (mMobileNetworkCallback != null) {
+            mLog.e("registerMobileNetworkRequest() already registered");
+            return;
+        }
+
+        final NetworkRequest mobileUpstreamRequest;
+        if (mDunRequired) {
+            mobileUpstreamRequest = new NetworkRequest.Builder()
+                    .addCapability(NET_CAPABILITY_DUN)
+                    .removeCapability(NET_CAPABILITY_NOT_RESTRICTED)
+                    .addTransportType(TRANSPORT_CELLULAR).build();
+        } else {
+            mobileUpstreamRequest = new NetworkRequest.Builder()
+                    .addCapability(NET_CAPABILITY_INTERNET)
+                    .addTransportType(TRANSPORT_CELLULAR).build();
+        }
+
+        // The existing default network and DUN callbacks will be notified.
+        // Therefore, to avoid duplicate notifications, we only register a no-op.
+        mMobileNetworkCallback = new UpstreamNetworkCallback(CALLBACK_MOBILE_REQUEST);
+
+        // The following use of the legacy type system cannot be removed until
+        // upstream selection no longer finds networks by legacy type.
+        // See also http://b/34364553 .
+        final int legacyType = mDunRequired ? TYPE_MOBILE_DUN : TYPE_MOBILE_HIPRI;
+
+        // TODO: Change the timeout from 0 (no onUnavailable callback) to some
+        // moderate callback timeout. This might be useful for updating some UI.
+        // Additionally, we log a message to aid in any subsequent debugging.
+        mLog.i("requesting mobile upstream network: " + mobileUpstreamRequest);
+
+        cm().requestNetwork(mobileUpstreamRequest, 0, legacyType, mHandler,
+                mMobileNetworkCallback);
+    }
+
+    /** Release mobile network request. */
+    public void releaseMobileNetworkRequest() {
+        if (mMobileNetworkCallback == null) return;
+
+        cm().unregisterNetworkCallback(mMobileNetworkCallback);
+        mMobileNetworkCallback = null;
+    }
+
+    // So many TODOs here, but chief among them is: make this functionality an
+    // integral part of this class such that whenever a higher priority network
+    // becomes available and useful we (a) file a request to keep it up as
+    // necessary and (b) change all upstream tracking state accordingly (by
+    // passing LinkProperties up to Tethering).
+    /**
+     * Select the first available network from |perferredTypes|.
+     */
+    public UpstreamNetworkState selectPreferredUpstreamType(Iterable<Integer> preferredTypes) {
+        final TypeStatePair typeStatePair = findFirstAvailableUpstreamByType(
+                mNetworkMap.values(), preferredTypes, isCellularUpstreamPermitted());
+
+        mLog.log("preferred upstream type: " + typeStatePair.type);
+
+        switch (typeStatePair.type) {
+            case TYPE_MOBILE_DUN:
+            case TYPE_MOBILE_HIPRI:
+                // Tethering just selected mobile upstream in spite of the default network being
+                // not mobile. This can happen because of the priority list.
+                // Notify EntitlementManager to check permission for using mobile upstream.
+                if (!mIsDefaultCellularUpstream) {
+                    mEntitlementMgr.maybeRunProvisioning();
+                }
+                // If we're on DUN, put our own grab on it.
+                registerMobileNetworkRequest();
+                break;
+            case TYPE_NONE:
+                // If we found NONE and mobile upstream is permitted we don't want to do this
+                // as we want any previous requests to keep trying to bring up something we can use.
+                if (!isCellularUpstreamPermitted()) releaseMobileNetworkRequest();
+                break;
+            default:
+                // If we've found an active upstream connection that's not DUN/HIPRI
+                // we should stop any outstanding DUN/HIPRI requests.
+                releaseMobileNetworkRequest();
+                break;
+        }
+
+        return typeStatePair.ns;
+    }
+
+    /**
+     * Get current preferred upstream network. If default network is cellular and DUN is required,
+     * preferred upstream would be DUN otherwise preferred upstream is the same as default network.
+     * Returns null if no current upstream is available.
+     */
+    public UpstreamNetworkState getCurrentPreferredUpstream() {
+        final UpstreamNetworkState dfltState = (mDefaultInternetNetwork != null)
+                ? mNetworkMap.get(mDefaultInternetNetwork)
+                : null;
+        if (isNetworkUsableAndNotCellular(dfltState)) return dfltState;
+
+        if (!isCellularUpstreamPermitted()) return null;
+
+        if (!mDunRequired) return dfltState;
+
+        // Find a DUN network. Note that code in Tethering causes a DUN request
+        // to be filed, but this might be moved into this class in future.
+        return findFirstDunNetwork(mNetworkMap.values());
+    }
+
+    /** Tell UpstreamNetworkMonitor which network is the current upstream of tethering. */
+    public void setCurrentUpstream(Network upstream) {
+        mTetheringUpstreamNetwork = upstream;
+    }
+
+    /** Return local prefixes. */
+    public Set<IpPrefix> getLocalPrefixes() {
+        return (Set<IpPrefix>) mLocalPrefixes.clone();
+    }
+
+    private boolean isCellularUpstreamPermitted() {
+        if (mEntitlementMgr != null) {
+            return mEntitlementMgr.isCellularUpstreamPermitted();
+        } else {
+            // This flow should only happens in testing.
+            return true;
+        }
+    }
+
+    private void handleAvailable(Network network) {
+        if (mNetworkMap.containsKey(network)) return;
+
+        if (VDBG) Log.d(TAG, "onAvailable for " + network);
+        mNetworkMap.put(network, new UpstreamNetworkState(null, null, network));
+    }
+
+    private void handleNetCap(Network network, NetworkCapabilities newNc) {
+        final UpstreamNetworkState prev = mNetworkMap.get(network);
+        if (prev == null || newNc.equals(prev.networkCapabilities)) {
+            // Ignore notifications about networks for which we have not yet
+            // received onAvailable() (should never happen) and any duplicate
+            // notifications (e.g. matching more than one of our callbacks).
+            return;
+        }
+
+        if (VDBG) {
+            Log.d(TAG, String.format("EVENT_ON_CAPABILITIES for %s: %s",
+                    network, newNc));
+        }
+
+        mNetworkMap.put(network, new UpstreamNetworkState(
+                prev.linkProperties, newNc, network));
+        // TODO: If sufficient information is available to select a more
+        // preferable upstream, do so now and notify the target.
+        notifyTarget(EVENT_ON_CAPABILITIES, network);
+    }
+
+    private void handleLinkProp(Network network, LinkProperties newLp) {
+        final UpstreamNetworkState prev = mNetworkMap.get(network);
+        if (prev == null || newLp.equals(prev.linkProperties)) {
+            // Ignore notifications about networks for which we have not yet
+            // received onAvailable() (should never happen) and any duplicate
+            // notifications (e.g. matching more than one of our callbacks).
+            return;
+        }
+
+        if (VDBG) {
+            Log.d(TAG, String.format("EVENT_ON_LINKPROPERTIES for %s: %s",
+                    network, newLp));
+        }
+
+        mNetworkMap.put(network, new UpstreamNetworkState(
+                newLp, prev.networkCapabilities, network));
+        // TODO: If sufficient information is available to select a more
+        // preferable upstream, do so now and notify the target.
+        notifyTarget(EVENT_ON_LINKPROPERTIES, network);
+    }
+
+    private void handleLost(Network network) {
+        // There are few TODOs within ConnectivityService's rematching code
+        // pertaining to spurious onLost() notifications.
+        //
+        // TODO: simplify this, probably if favor of code that:
+        //     - selects a new upstream if mTetheringUpstreamNetwork has
+        //       been lost (by any callback)
+        //     - deletes the entry from the map only when the LISTEN_ALL
+        //       callback gets notified.
+
+        if (!mNetworkMap.containsKey(network)) {
+            // Ignore loss of networks about which we had not previously
+            // learned any information or for which we have already processed
+            // an onLost() notification.
+            return;
+        }
+
+        if (VDBG) Log.d(TAG, "EVENT_ON_LOST for " + network);
+
+        // TODO: If sufficient information is available to select a more
+        // preferable upstream, do so now and notify the target.  Likewise,
+        // if the current upstream network is gone, notify the target of the
+        // fact that we now have no upstream at all.
+        notifyTarget(EVENT_ON_LOST, mNetworkMap.remove(network));
+    }
+
+    private void recomputeLocalPrefixes() {
+        final HashSet<IpPrefix> localPrefixes = allLocalPrefixes(mNetworkMap.values());
+        if (!mLocalPrefixes.equals(localPrefixes)) {
+            mLocalPrefixes = localPrefixes;
+            notifyTarget(NOTIFY_LOCAL_PREFIXES, localPrefixes.clone());
+        }
+    }
+
+    // Fetch (and cache) a ConnectivityManager only if and when we need one.
+    private ConnectivityManager cm() {
+        if (mCM == null) {
+            // MUST call the String variant to be able to write unittests.
+            mCM = (ConnectivityManager) mContext.getSystemService(Context.CONNECTIVITY_SERVICE);
+        }
+        return mCM;
+    }
+
+    /**
+     * A NetworkCallback class that handles information of interest directly
+     * in the thread on which it is invoked. To avoid locking, this MUST be
+     * run on the same thread as the target state machine's handler.
+     */
+    private class UpstreamNetworkCallback extends NetworkCallback {
+        private final int mCallbackType;
+
+        UpstreamNetworkCallback(int callbackType) {
+            mCallbackType = callbackType;
+        }
+
+        @Override
+        public void onAvailable(Network network) {
+            handleAvailable(network);
+        }
+
+        @Override
+        public void onCapabilitiesChanged(Network network, NetworkCapabilities newNc) {
+            if (mCallbackType == CALLBACK_DEFAULT_INTERNET) {
+                mDefaultInternetNetwork = network;
+                final boolean newIsCellular = isCellular(newNc);
+                if (mIsDefaultCellularUpstream != newIsCellular) {
+                    mIsDefaultCellularUpstream = newIsCellular;
+                    mEntitlementMgr.notifyUpstream(newIsCellular);
+                }
+                return;
+            }
+
+            handleNetCap(network, newNc);
+        }
+
+        @Override
+        public void onLinkPropertiesChanged(Network network, LinkProperties newLp) {
+            if (mCallbackType == CALLBACK_DEFAULT_INTERNET) return;
+
+            handleLinkProp(network, newLp);
+            // Any non-LISTEN_ALL callback will necessarily concern a network that will
+            // also match the LISTEN_ALL callback by construction of the LISTEN_ALL callback.
+            // So it's not useful to do this work for non-LISTEN_ALL callbacks.
+            if (mCallbackType == CALLBACK_LISTEN_ALL) {
+                recomputeLocalPrefixes();
+            }
+        }
+
+        @Override
+        public void onLost(Network network) {
+            if (mCallbackType == CALLBACK_DEFAULT_INTERNET) {
+                mDefaultInternetNetwork = null;
+                mIsDefaultCellularUpstream = false;
+                mEntitlementMgr.notifyUpstream(false);
+                return;
+            }
+
+            handleLost(network);
+            // Any non-LISTEN_ALL callback will necessarily concern a network that will
+            // also match the LISTEN_ALL callback by construction of the LISTEN_ALL callback.
+            // So it's not useful to do this work for non-LISTEN_ALL callbacks.
+            if (mCallbackType == CALLBACK_LISTEN_ALL) {
+                recomputeLocalPrefixes();
+            }
+        }
+    }
+
+    private void releaseCallback(NetworkCallback cb) {
+        if (cb != null) cm().unregisterNetworkCallback(cb);
+    }
+
+    private void notifyTarget(int which, Network network) {
+        notifyTarget(which, mNetworkMap.get(network));
+    }
+
+    private void notifyTarget(int which, Object obj) {
+        mTarget.sendMessage(mWhat, which, 0, obj);
+    }
+
+    private static class TypeStatePair {
+        public int type = TYPE_NONE;
+        public UpstreamNetworkState ns = null;
+    }
+
+    private static TypeStatePair findFirstAvailableUpstreamByType(
+            Iterable<UpstreamNetworkState> netStates, Iterable<Integer> preferredTypes,
+            boolean isCellularUpstreamPermitted) {
+        final TypeStatePair result = new TypeStatePair();
+
+        for (int type : preferredTypes) {
+            NetworkCapabilities nc;
+            try {
+                nc = networkCapabilitiesForType(type);
+            } catch (IllegalArgumentException iae) {
+                Log.e(TAG, "No NetworkCapabilities mapping for legacy type: " + type);
+                continue;
+            }
+            if (!isCellularUpstreamPermitted && isCellular(nc)) {
+                continue;
+            }
+
+            for (UpstreamNetworkState value : netStates) {
+                if (!nc.satisfiedByNetworkCapabilities(value.networkCapabilities)) {
+                    continue;
+                }
+
+                result.type = type;
+                result.ns = value;
+                return result;
+            }
+        }
+
+        return result;
+    }
+
+    private static HashSet<IpPrefix> allLocalPrefixes(Iterable<UpstreamNetworkState> netStates) {
+        final HashSet<IpPrefix> prefixSet = new HashSet<>();
+
+        for (UpstreamNetworkState ns : netStates) {
+            final LinkProperties lp = ns.linkProperties;
+            if (lp == null) continue;
+            prefixSet.addAll(PrefixUtils.localPrefixesFrom(lp));
+        }
+
+        return prefixSet;
+    }
+
+    private static boolean isCellular(UpstreamNetworkState ns) {
+        return (ns != null) && isCellular(ns.networkCapabilities);
+    }
+
+    private static boolean isCellular(NetworkCapabilities nc) {
+        return (nc != null) && nc.hasTransport(TRANSPORT_CELLULAR)
+               && nc.hasCapability(NET_CAPABILITY_NOT_VPN);
+    }
+
+    private static boolean hasCapability(UpstreamNetworkState ns, int netCap) {
+        return (ns != null) && (ns.networkCapabilities != null)
+               && ns.networkCapabilities.hasCapability(netCap);
+    }
+
+    private static boolean isNetworkUsableAndNotCellular(UpstreamNetworkState ns) {
+        return (ns != null) && (ns.networkCapabilities != null) && (ns.linkProperties != null)
+               && !isCellular(ns.networkCapabilities);
+    }
+
+    private static UpstreamNetworkState findFirstDunNetwork(
+            Iterable<UpstreamNetworkState> netStates) {
+        for (UpstreamNetworkState ns : netStates) {
+            if (isCellular(ns) && hasCapability(ns, NET_CAPABILITY_DUN)) return ns;
+        }
+
+        return null;
+    }
+
+    /**
+     * Given a legacy type (TYPE_WIFI, ...) returns the corresponding NetworkCapabilities instance.
+     * This function is used for deprecated legacy type and be disabled by default.
+     */
+    @VisibleForTesting
+    public static NetworkCapabilities networkCapabilitiesForType(int type) {
+        final NetworkCapabilities.Builder builder = new NetworkCapabilities.Builder();
+
+        // Map from type to transports.
+        final int notFound = -1;
+        final int transport = sLegacyTypeToTransport.get(type, notFound);
+        if (transport == notFound) {
+            throw new IllegalArgumentException("unknown legacy type: " + type);
+        }
+        builder.addTransportType(transport);
+
+        if (type == TYPE_MOBILE_DUN) {
+            builder.addCapability(NetworkCapabilities.NET_CAPABILITY_DUN);
+            // DUN is restricted network, see NetworkCapabilities#FORCE_RESTRICTED_CAPABILITIES.
+            builder.removeCapability(NetworkCapabilities.NET_CAPABILITY_NOT_RESTRICTED);
+        } else {
+            builder.addCapability(NetworkCapabilities.NET_CAPABILITY_INTERNET);
+        }
+        return builder.build();
+    }
+}
diff --git a/Tethering/src/com/android/networkstack/tethering/UpstreamNetworkState.java b/Tethering/src/com/android/networkstack/tethering/UpstreamNetworkState.java
new file mode 100644
index 0000000..bab9f84
--- /dev/null
+++ b/Tethering/src/com/android/networkstack/tethering/UpstreamNetworkState.java
@@ -0,0 +1,51 @@
+/*
+ * Copyright (C) 2019 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package com.android.networkstack.tethering;
+
+import android.net.LinkProperties;
+import android.net.Network;
+import android.net.NetworkCapabilities;
+
+import androidx.annotation.NonNull;
+
+/**
+ * Snapshot of tethering upstream network state.
+ */
+public class UpstreamNetworkState {
+    /** {@link LinkProperties}. */
+    public final LinkProperties linkProperties;
+    /** {@link NetworkCapabilities}. */
+    public final NetworkCapabilities networkCapabilities;
+    /** {@link Network}. */
+    public final Network network;
+
+    /** Constructs a new UpstreamNetworkState. */
+    public UpstreamNetworkState(LinkProperties linkProperties,
+            NetworkCapabilities networkCapabilities, Network network) {
+        this.linkProperties = linkProperties;
+        this.networkCapabilities = networkCapabilities;
+        this.network = network;
+    }
+
+    @NonNull
+    @Override
+    public String toString() {
+        return String.format("UpstreamNetworkState{%s, %s, %s}",
+                network == null ? "null" : network,
+                networkCapabilities == null ? "null" : networkCapabilities,
+                linkProperties == null ? "null" : linkProperties);
+    }
+}
diff --git a/Tethering/tests/Android.bp b/Tethering/tests/Android.bp
new file mode 100644
index 0000000..731144c
--- /dev/null
+++ b/Tethering/tests/Android.bp
@@ -0,0 +1,24 @@
+//
+// Copyright (C) 2020 The Android Open Source Project
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//      http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+//
+
+filegroup {
+    name: "TetheringTestsJarJarRules",
+    srcs: ["jarjar-rules.txt"],
+    visibility: [
+        "//frameworks/base/packages/Tethering/tests:__subpackages__",
+        "//packages/modules/Connectivity/Tethering/tests:__subpackages__",
+    ]
+}
diff --git a/Tethering/tests/integration/Android.bp b/Tethering/tests/integration/Android.bp
new file mode 100644
index 0000000..5765c01
--- /dev/null
+++ b/Tethering/tests/integration/Android.bp
@@ -0,0 +1,85 @@
+//
+// Copyright (C) 2020 The Android Open Source Project
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//      http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+//
+java_defaults {
+    name: "TetheringIntegrationTestsDefaults",
+    srcs: [
+        "src/**/*.java",
+        "src/**/*.kt",
+    ],
+    static_libs: [
+        "NetworkStackApiStableLib",
+        "androidx.test.rules",
+        "mockito-target-extended-minus-junit4",
+        "net-tests-utils",
+        "testables",
+    ],
+    libs: [
+        "android.test.runner",
+        "android.test.base",
+        "android.test.mock",
+    ],
+    jni_libs: [
+        // For mockito extended
+        "libdexmakerjvmtiagent",
+        "libstaticjvmtiagent",
+    ],
+    jarjar_rules: ":NetworkStackJarJarRules",
+}
+
+android_library {
+    name: "TetheringIntegrationTestsLib",
+    platform_apis: true,
+    defaults: ["TetheringIntegrationTestsDefaults"],
+    visibility: ["//cts/tests/tests/tethering"]
+}
+
+android_test {
+    name: "TetheringIntegrationTests",
+    platform_apis: true,
+    defaults: ["TetheringIntegrationTestsDefaults"],
+    test_suites: [
+        "device-tests",
+        "mts",
+    ],
+    compile_multilib: "both",
+}
+
+// Special version of the tethering tests that includes all tests necessary for code coverage
+// purposes. This is currently the union of TetheringTests, TetheringIntegrationTests and
+// NetworkStackTests.
+android_test {
+    name: "TetheringCoverageTests",
+    platform_apis: true,
+    test_suites: ["device-tests", "mts"],
+    test_config: "AndroidTest_Coverage.xml",
+    defaults: ["libnetworkstackutilsjni_deps"],
+    static_libs: [
+        "NetworkStaticLibTestsLib",
+        "NetworkStackTestsLib",
+        "TetheringTestsLib",
+        "TetheringIntegrationTestsLib",
+    ],
+    jni_libs: [
+        // For mockito extended
+        "libdexmakerjvmtiagent",
+        "libstaticjvmtiagent",
+        // For NetworkStackUtils included in NetworkStackBase
+        "libnetworkstackutilsjni",
+    ],
+    jarjar_rules: ":TetheringTestsJarJarRules",
+    compile_multilib: "both",
+    manifest: "AndroidManifest_coverage.xml",
+}
diff --git a/Tethering/tests/integration/AndroidManifest.xml b/Tethering/tests/integration/AndroidManifest.xml
new file mode 100644
index 0000000..fddfaad
--- /dev/null
+++ b/Tethering/tests/integration/AndroidManifest.xml
@@ -0,0 +1,28 @@
+<?xml version="1.0" encoding="utf-8"?>
+<!-- Copyright (C) 2020 The Android Open Source Project
+
+     Licensed under the Apache License, Version 2.0 (the "License");
+     you may not use this file except in compliance with the License.
+     You may obtain a copy of the License at
+
+          http://www.apache.org/licenses/LICENSE-2.0
+
+     Unless required by applicable law or agreed to in writing, software
+     distributed under the License is distributed on an "AS IS" BASIS,
+     WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+     See the License for the specific language governing permissions and
+     limitations under the License.
+-->
+<manifest xmlns:android="http://schemas.android.com/apk/res/android"
+          package="com.android.networkstack.tethering.tests.integration">
+
+    <uses-permission android:name="android.permission.INTERNET"/>
+
+    <application android:debuggable="true">
+        <uses-library android:name="android.test.runner" />
+    </application>
+    <instrumentation android:name="androidx.test.runner.AndroidJUnitRunner"
+        android:targetPackage="com.android.networkstack.tethering.tests.integration"
+        android:label="Tethering integration tests">
+    </instrumentation>
+</manifest>
diff --git a/Tethering/tests/integration/AndroidManifest_coverage.xml b/Tethering/tests/integration/AndroidManifest_coverage.xml
new file mode 100644
index 0000000..06de00d
--- /dev/null
+++ b/Tethering/tests/integration/AndroidManifest_coverage.xml
@@ -0,0 +1,29 @@
+<?xml version="1.0" encoding="utf-8"?>
+<!-- Copyright (C) 2020 The Android Open Source Project
+
+     Licensed under the Apache License, Version 2.0 (the "License");
+     you may not use this file except in compliance with the License.
+     You may obtain a copy of the License at
+
+          http://www.apache.org/licenses/LICENSE-2.0
+
+     Unless required by applicable law or agreed to in writing, software
+     distributed under the License is distributed on an "AS IS" BASIS,
+     WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+     See the License for the specific language governing permissions and
+     limitations under the License.
+-->
+<manifest xmlns:android="http://schemas.android.com/apk/res/android"
+          xmlns:tools="http://schemas.android.com/tools"
+          package="com.android.networkstack.tethering.tests.coverage">
+
+    <application tools:replace="android:label"
+                 android:debuggable="true"
+                 android:label="Tethering coverage tests">
+        <uses-library android:name="android.test.runner" />
+    </application>
+    <instrumentation android:name="androidx.test.runner.AndroidJUnitRunner"
+                     android:targetPackage="com.android.networkstack.tethering.tests.coverage"
+                     android:label="Tethering coverage tests">
+    </instrumentation>
+</manifest>
diff --git a/Tethering/tests/integration/AndroidTest_Coverage.xml b/Tethering/tests/integration/AndroidTest_Coverage.xml
new file mode 100644
index 0000000..3def209
--- /dev/null
+++ b/Tethering/tests/integration/AndroidTest_Coverage.xml
@@ -0,0 +1,12 @@
+<configuration description="Runs coverage tests for Tethering">
+    <target_preparer class="com.android.tradefed.targetprep.TestAppInstallSetup">
+        <option name="test-file-name" value="TetheringCoverageTests.apk" />
+    </target_preparer>
+
+    <option name="test-tag" value="TetheringCoverageTests" />
+    <test class="com.android.tradefed.testtype.AndroidJUnitTest" >
+        <option name="package" value="com.android.networkstack.tethering.tests.coverage" />
+        <option name="runner" value="androidx.test.runner.AndroidJUnitRunner" />
+        <option name="hidden-api-checks" value="false"/>
+    </test>
+</configuration>
\ No newline at end of file
diff --git a/Tethering/tests/integration/src/android/net/EthernetTetheringTest.java b/Tethering/tests/integration/src/android/net/EthernetTetheringTest.java
new file mode 100644
index 0000000..d206ea0
--- /dev/null
+++ b/Tethering/tests/integration/src/android/net/EthernetTetheringTest.java
@@ -0,0 +1,566 @@
+/*
+ * Copyright (C) 2020 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package android.net;
+
+import static android.Manifest.permission.MANAGE_TEST_NETWORKS;
+import static android.Manifest.permission.NETWORK_SETTINGS;
+import static android.Manifest.permission.TETHER_PRIVILEGED;
+import static android.net.TetheringManager.TETHERING_ETHERNET;
+
+import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertNotNull;
+import static org.junit.Assert.assertNull;
+import static org.junit.Assert.assertTrue;
+import static org.junit.Assert.fail;
+import static org.junit.Assume.assumeFalse;
+import static org.junit.Assume.assumeTrue;
+
+import android.app.UiAutomation;
+import android.content.Context;
+import android.net.EthernetManager.TetheredInterfaceCallback;
+import android.net.EthernetManager.TetheredInterfaceRequest;
+import android.net.TetheringManager.StartTetheringCallback;
+import android.net.TetheringManager.TetheringEventCallback;
+import android.net.TetheringManager.TetheringRequest;
+import android.net.dhcp.DhcpAckPacket;
+import android.net.dhcp.DhcpOfferPacket;
+import android.net.dhcp.DhcpPacket;
+import android.os.Handler;
+import android.os.HandlerThread;
+import android.os.SystemClock;
+import android.os.SystemProperties;
+import android.system.Os;
+import android.util.Log;
+
+import androidx.test.InstrumentationRegistry;
+import androidx.test.filters.MediumTest;
+import androidx.test.runner.AndroidJUnit4;
+
+import com.android.testutils.HandlerUtils;
+import com.android.testutils.TapPacketReader;
+
+import org.junit.After;
+import org.junit.Before;
+import org.junit.Test;
+import org.junit.runner.RunWith;
+
+import java.io.FileDescriptor;
+import java.net.Inet4Address;
+import java.net.InterfaceAddress;
+import java.net.NetworkInterface;
+import java.net.SocketException;
+import java.nio.ByteBuffer;
+import java.util.Collection;
+import java.util.List;
+import java.util.Random;
+import java.util.concurrent.CompletableFuture;
+import java.util.concurrent.CountDownLatch;
+import java.util.concurrent.TimeUnit;
+import java.util.concurrent.TimeoutException;
+
+@RunWith(AndroidJUnit4.class)
+@MediumTest
+public class EthernetTetheringTest {
+
+    private static final String TAG = EthernetTetheringTest.class.getSimpleName();
+    private static final int TIMEOUT_MS = 5000;
+    private static final int PACKET_READ_TIMEOUT_MS = 100;
+    private static final int DHCP_DISCOVER_ATTEMPTS = 10;
+    private static final byte[] DHCP_REQUESTED_PARAMS = new byte[] {
+            DhcpPacket.DHCP_SUBNET_MASK,
+            DhcpPacket.DHCP_ROUTER,
+            DhcpPacket.DHCP_DNS_SERVER,
+            DhcpPacket.DHCP_LEASE_TIME,
+    };
+    private static final String DHCP_HOSTNAME = "testhostname";
+
+    private final Context mContext = InstrumentationRegistry.getContext();
+    private final EthernetManager mEm = mContext.getSystemService(EthernetManager.class);
+    private final TetheringManager mTm = mContext.getSystemService(TetheringManager.class);
+
+    private TestNetworkInterface mTestIface;
+    private HandlerThread mHandlerThread;
+    private Handler mHandler;
+    private TapPacketReader mTapPacketReader;
+
+    private TetheredInterfaceRequester mTetheredInterfaceRequester;
+    private MyTetheringEventCallback mTetheringEventCallback;
+
+    private UiAutomation mUiAutomation =
+            InstrumentationRegistry.getInstrumentation().getUiAutomation();
+    private boolean mRunTests;
+
+    @Before
+    public void setUp() throws Exception {
+        // Needed to create a TestNetworkInterface, to call requestTetheredInterface, and to receive
+        // tethered client callbacks.
+        mUiAutomation.adoptShellPermissionIdentity(
+                MANAGE_TEST_NETWORKS, NETWORK_SETTINGS, TETHER_PRIVILEGED);
+        mRunTests = mTm.isTetheringSupported() && mEm != null;
+        assumeTrue(mRunTests);
+
+        mHandlerThread = new HandlerThread(getClass().getSimpleName());
+        mHandlerThread.start();
+        mHandler = new Handler(mHandlerThread.getLooper());
+        mTetheredInterfaceRequester = new TetheredInterfaceRequester(mHandler, mEm);
+    }
+
+    private void cleanUp() throws Exception {
+        mTm.stopTethering(TETHERING_ETHERNET);
+        if (mTetheringEventCallback != null) {
+            mTetheringEventCallback.awaitInterfaceUntethered();
+            mTetheringEventCallback.unregister();
+            mTetheringEventCallback = null;
+        }
+        if (mTapPacketReader != null) {
+            TapPacketReader reader = mTapPacketReader;
+            mHandler.post(() -> reader.stop());
+            mTapPacketReader = null;
+        }
+        mHandlerThread.quitSafely();
+        mTetheredInterfaceRequester.release();
+        mEm.setIncludeTestInterfaces(false);
+        maybeDeleteTestInterface();
+    }
+
+    @After
+    public void tearDown() throws Exception {
+        try {
+            if (mRunTests) cleanUp();
+        } finally {
+            mUiAutomation.dropShellPermissionIdentity();
+        }
+    }
+
+    @Test
+    public void testVirtualEthernetAlreadyExists() throws Exception {
+        // This test requires manipulating packets. Skip if there is a physical Ethernet connected.
+        assumeFalse(mEm.isAvailable());
+
+        mTestIface = createTestInterface();
+        // This must be done now because as soon as setIncludeTestInterfaces(true) is called, the
+        // interface will be placed in client mode, which will delete the link-local address.
+        // At that point NetworkInterface.getByName() will cease to work on the interface, because
+        // starting in R NetworkInterface can no longer see interfaces without IP addresses.
+        int mtu = getMTU(mTestIface);
+
+        Log.d(TAG, "Including test interfaces");
+        mEm.setIncludeTestInterfaces(true);
+
+        final String iface = mTetheredInterfaceRequester.getInterface();
+        assertEquals("TetheredInterfaceCallback for unexpected interface",
+                mTestIface.getInterfaceName(), iface);
+
+        checkVirtualEthernet(mTestIface, mtu);
+    }
+
+    @Test
+    public void testVirtualEthernet() throws Exception {
+        // This test requires manipulating packets. Skip if there is a physical Ethernet connected.
+        assumeFalse(mEm.isAvailable());
+
+        CompletableFuture<String> futureIface = mTetheredInterfaceRequester.requestInterface();
+
+        mEm.setIncludeTestInterfaces(true);
+
+        mTestIface = createTestInterface();
+
+        final String iface = futureIface.get(TIMEOUT_MS, TimeUnit.MILLISECONDS);
+        assertEquals("TetheredInterfaceCallback for unexpected interface",
+                mTestIface.getInterfaceName(), iface);
+
+        checkVirtualEthernet(mTestIface, getMTU(mTestIface));
+    }
+
+    @Test
+    public void testStaticIpv4() throws Exception {
+        assumeFalse(mEm.isAvailable());
+
+        mEm.setIncludeTestInterfaces(true);
+
+        mTestIface = createTestInterface();
+
+        final String iface = mTetheredInterfaceRequester.getInterface();
+        assertEquals("TetheredInterfaceCallback for unexpected interface",
+                mTestIface.getInterfaceName(), iface);
+
+        assertInvalidStaticIpv4Request(iface, null, null);
+        assertInvalidStaticIpv4Request(iface, "2001:db8::1/64", "2001:db8:2::/64");
+        assertInvalidStaticIpv4Request(iface, "192.0.2.2/28", "2001:db8:2::/28");
+        assertInvalidStaticIpv4Request(iface, "2001:db8:2::/28", "192.0.2.2/28");
+        assertInvalidStaticIpv4Request(iface, "192.0.2.2/28", null);
+        assertInvalidStaticIpv4Request(iface, null, "192.0.2.2/28");
+        assertInvalidStaticIpv4Request(iface, "192.0.2.3/27", "192.0.2.2/28");
+
+        final String localAddr = "192.0.2.3/28";
+        final String clientAddr = "192.0.2.2/28";
+        mTetheringEventCallback = enableEthernetTethering(iface,
+                requestWithStaticIpv4(localAddr, clientAddr));
+
+        mTetheringEventCallback.awaitInterfaceTethered();
+        assertInterfaceHasIpAddress(iface, localAddr);
+
+        byte[] client1 = MacAddress.fromString("1:2:3:4:5:6").toByteArray();
+        byte[] client2 = MacAddress.fromString("a:b:c:d:e:f").toByteArray();
+
+        FileDescriptor fd = mTestIface.getFileDescriptor().getFileDescriptor();
+        mTapPacketReader = makePacketReader(fd, getMTU(mTestIface));
+        DhcpResults dhcpResults = runDhcp(fd, client1);
+        assertEquals(new LinkAddress(clientAddr), dhcpResults.ipAddress);
+
+        try {
+            runDhcp(fd, client2);
+            fail("Only one client should get an IP address");
+        } catch (TimeoutException expected) { }
+
+    }
+
+    private boolean isAdbOverNetwork() {
+        // If adb TCP port opened, this test may running by adb over network.
+        return (SystemProperties.getInt("persist.adb.tcp.port", -1) > -1)
+                || (SystemProperties.getInt("service.adb.tcp.port", -1) > -1);
+    }
+
+    @Test
+    public void testPhysicalEthernet() throws Exception {
+        assumeTrue(mEm.isAvailable());
+        // Do not run this test if adb is over network and ethernet is connected.
+        // It is likely the adb run over ethernet, the adb would break when ethernet is switching
+        // from client mode to server mode. See b/160389275.
+        assumeFalse(isAdbOverNetwork());
+
+        // Get an interface to use.
+        final String iface = mTetheredInterfaceRequester.getInterface();
+
+        // Enable Ethernet tethering and check that it starts.
+        mTetheringEventCallback = enableEthernetTethering(iface);
+
+        // There is nothing more we can do on a physical interface without connecting an actual
+        // client, which is not possible in this test.
+    }
+
+    private static final class MyTetheringEventCallback implements TetheringEventCallback {
+        private final TetheringManager mTm;
+        private final CountDownLatch mTetheringStartedLatch = new CountDownLatch(1);
+        private final CountDownLatch mTetheringStoppedLatch = new CountDownLatch(1);
+        private final CountDownLatch mClientConnectedLatch = new CountDownLatch(1);
+        private final String mIface;
+
+        private volatile boolean mInterfaceWasTethered = false;
+        private volatile boolean mUnregistered = false;
+        private volatile Collection<TetheredClient> mClients = null;
+
+        MyTetheringEventCallback(TetheringManager tm, String iface) {
+            mTm = tm;
+            mIface = iface;
+        }
+
+        public void unregister() {
+            mTm.unregisterTetheringEventCallback(this);
+            mUnregistered = true;
+        }
+
+        @Override
+        public void onTetheredInterfacesChanged(List<String> interfaces) {
+            // Ignore stale callbacks registered by previous test cases.
+            if (mUnregistered) return;
+
+            final boolean wasTethered = mTetheringStartedLatch.getCount() == 0;
+            if (!mInterfaceWasTethered && (mIface == null || interfaces.contains(mIface))) {
+                // This interface is being tethered for the first time.
+                Log.d(TAG, "Tethering started: " + interfaces);
+                mInterfaceWasTethered = true;
+                mTetheringStartedLatch.countDown();
+            } else if (mInterfaceWasTethered && !interfaces.contains(mIface)) {
+                Log.d(TAG, "Tethering stopped: " + interfaces);
+                mTetheringStoppedLatch.countDown();
+            }
+        }
+
+        public void awaitInterfaceTethered() throws Exception {
+            assertTrue("Ethernet not tethered after " + TIMEOUT_MS + "ms",
+                    mTetheringStartedLatch.await(TIMEOUT_MS, TimeUnit.MILLISECONDS));
+        }
+
+        public void awaitInterfaceUntethered() throws Exception {
+            // Don't block teardown if the interface was never tethered.
+            // This is racy because the interface might become tethered right after this check, but
+            // that can only happen in tearDown if startTethering timed out, which likely means
+            // the test has already failed.
+            if (!mInterfaceWasTethered) return;
+
+            assertTrue(mIface + " not untethered after " + TIMEOUT_MS + "ms",
+                    mTetheringStoppedLatch.await(TIMEOUT_MS, TimeUnit.MILLISECONDS));
+        }
+
+        @Override
+        public void onError(String ifName, int error) {
+            // Ignore stale callbacks registered by previous test cases.
+            if (mUnregistered) return;
+
+            fail("TetheringEventCallback got error:" + error + " on iface " + ifName);
+        }
+
+        @Override
+        public void onClientsChanged(Collection<TetheredClient> clients) {
+            // Ignore stale callbacks registered by previous test cases.
+            if (mUnregistered) return;
+
+            Log.d(TAG, "Got clients changed: " + clients);
+            mClients = clients;
+            if (clients.size() > 0) {
+                mClientConnectedLatch.countDown();
+            }
+        }
+
+        public Collection<TetheredClient> awaitClientConnected() throws Exception {
+            assertTrue("Did not receive client connected callback after " + TIMEOUT_MS + "ms",
+                    mClientConnectedLatch.await(TIMEOUT_MS, TimeUnit.MILLISECONDS));
+            return mClients;
+        }
+    }
+
+    private MyTetheringEventCallback enableEthernetTethering(String iface,
+            TetheringRequest request) throws Exception {
+        MyTetheringEventCallback callback = new MyTetheringEventCallback(mTm, iface);
+        mTm.registerTetheringEventCallback(mHandler::post, callback);
+
+        StartTetheringCallback startTetheringCallback = new StartTetheringCallback() {
+            @Override
+            public void onTetheringFailed(int resultCode) {
+                fail("Unexpectedly got onTetheringFailed");
+            }
+        };
+        Log.d(TAG, "Starting Ethernet tethering");
+        mTm.startTethering(request, mHandler::post /* executor */,  startTetheringCallback);
+        callback.awaitInterfaceTethered();
+        return callback;
+    }
+
+    private MyTetheringEventCallback enableEthernetTethering(String iface) throws Exception {
+        return enableEthernetTethering(iface,
+                new TetheringRequest.Builder(TETHERING_ETHERNET)
+                .setShouldShowEntitlementUi(false).build());
+    }
+
+    private int getMTU(TestNetworkInterface iface) throws SocketException {
+        NetworkInterface nif = NetworkInterface.getByName(iface.getInterfaceName());
+        assertNotNull("Can't get NetworkInterface object for " + iface.getInterfaceName(), nif);
+        return nif.getMTU();
+    }
+
+    private TapPacketReader makePacketReader(FileDescriptor fd, int mtu) {
+        final TapPacketReader reader = new TapPacketReader(mHandler, fd, mtu);
+        mHandler.post(() -> reader.start());
+        HandlerUtils.waitForIdle(mHandler, TIMEOUT_MS);
+        return reader;
+    }
+
+    private void checkVirtualEthernet(TestNetworkInterface iface, int mtu) throws Exception {
+        FileDescriptor fd = iface.getFileDescriptor().getFileDescriptor();
+        mTapPacketReader = makePacketReader(fd, mtu);
+        mTetheringEventCallback = enableEthernetTethering(iface.getInterfaceName());
+        checkTetheredClientCallbacks(fd);
+    }
+
+    private DhcpResults runDhcp(FileDescriptor fd, byte[] clientMacAddr) throws Exception {
+        // We have to retransmit DHCP requests because IpServer declares itself to be ready before
+        // its DhcpServer is actually started. TODO: fix this race and remove this loop.
+        DhcpPacket offerPacket = null;
+        for (int i = 0; i < DHCP_DISCOVER_ATTEMPTS; i++) {
+            Log.d(TAG, "Sending DHCP discover");
+            sendDhcpDiscover(fd, clientMacAddr);
+            offerPacket = getNextDhcpPacket();
+            if (offerPacket instanceof DhcpOfferPacket) break;
+        }
+        if (!(offerPacket instanceof DhcpOfferPacket)) {
+            throw new TimeoutException("No DHCPOFFER received on interface within timeout");
+        }
+
+        sendDhcpRequest(fd, offerPacket, clientMacAddr);
+        DhcpPacket ackPacket = getNextDhcpPacket();
+        if (!(ackPacket instanceof DhcpAckPacket)) {
+            throw new TimeoutException("No DHCPACK received on interface within timeout");
+        }
+
+        return ackPacket.toDhcpResults();
+    }
+
+    private void checkTetheredClientCallbacks(FileDescriptor fd) throws Exception {
+        // Create a fake client.
+        byte[] clientMacAddr = new byte[6];
+        new Random().nextBytes(clientMacAddr);
+
+        DhcpResults dhcpResults = runDhcp(fd, clientMacAddr);
+
+        final Collection<TetheredClient> clients = mTetheringEventCallback.awaitClientConnected();
+        assertEquals(1, clients.size());
+        final TetheredClient client = clients.iterator().next();
+
+        // Check the MAC address.
+        assertEquals(MacAddress.fromBytes(clientMacAddr), client.getMacAddress());
+        assertEquals(TETHERING_ETHERNET, client.getTetheringType());
+
+        // Check the hostname.
+        assertEquals(1, client.getAddresses().size());
+        TetheredClient.AddressInfo info = client.getAddresses().get(0);
+        assertEquals(DHCP_HOSTNAME, info.getHostname());
+
+        // Check the address is the one that was handed out in the DHCP ACK.
+        assertLinkAddressMatches(dhcpResults.ipAddress, info.getAddress());
+
+        // Check that the lifetime is correct +/- 10s.
+        final long now = SystemClock.elapsedRealtime();
+        final long actualLeaseDuration = (info.getAddress().getExpirationTime() - now) / 1000;
+        final String msg = String.format("IP address should have lifetime of %d, got %d",
+                dhcpResults.leaseDuration, actualLeaseDuration);
+        assertTrue(msg, Math.abs(dhcpResults.leaseDuration - actualLeaseDuration) < 10);
+    }
+
+    private DhcpPacket getNextDhcpPacket() throws ParseException {
+        byte[] packet;
+        while ((packet = mTapPacketReader.popPacket(PACKET_READ_TIMEOUT_MS)) != null) {
+            try {
+                return DhcpPacket.decodeFullPacket(packet, packet.length, DhcpPacket.ENCAP_L2);
+            } catch (DhcpPacket.ParseException e) {
+                // Not a DHCP packet. Continue.
+            }
+        }
+        return null;
+    }
+
+    private static final class TetheredInterfaceRequester implements TetheredInterfaceCallback {
+        private final CountDownLatch mInterfaceAvailableLatch = new CountDownLatch(1);
+        private final Handler mHandler;
+        private final EthernetManager mEm;
+
+        private TetheredInterfaceRequest mRequest;
+        private final CompletableFuture<String> mFuture = new CompletableFuture<>();
+
+        TetheredInterfaceRequester(Handler handler, EthernetManager em) {
+            mHandler = handler;
+            mEm = em;
+        }
+
+        @Override
+        public void onAvailable(String iface) {
+            Log.d(TAG, "Ethernet interface available: " + iface);
+            mFuture.complete(iface);
+        }
+
+        @Override
+        public void onUnavailable() {
+            mFuture.completeExceptionally(new IllegalStateException("onUnavailable received"));
+        }
+
+        public CompletableFuture<String> requestInterface() {
+            assertNull("BUG: more than one tethered interface request", mRequest);
+            Log.d(TAG, "Requesting tethered interface");
+            mRequest = mEm.requestTetheredInterface(mHandler::post, this);
+            return mFuture;
+        }
+
+        public String getInterface() throws Exception {
+            return requestInterface().get(TIMEOUT_MS, TimeUnit.MILLISECONDS);
+        }
+
+        public void release() {
+            if (mRequest != null) {
+                mFuture.obtrudeException(new IllegalStateException("Request already released"));
+                mRequest.release();
+                mRequest = null;
+            }
+        }
+    }
+
+    private void sendDhcpDiscover(FileDescriptor fd, byte[] macAddress) throws Exception {
+        ByteBuffer packet = DhcpPacket.buildDiscoverPacket(DhcpPacket.ENCAP_L2,
+                new Random().nextInt() /* transactionId */, (short) 0 /* secs */,
+                macAddress,  false /* unicast */, DHCP_REQUESTED_PARAMS,
+                false /* rapid commit */,  DHCP_HOSTNAME);
+        sendPacket(fd, packet);
+    }
+
+    private void sendDhcpRequest(FileDescriptor fd, DhcpPacket offerPacket, byte[] macAddress)
+            throws Exception {
+        DhcpResults results = offerPacket.toDhcpResults();
+        Inet4Address clientIp = (Inet4Address) results.ipAddress.getAddress();
+        Inet4Address serverIdentifier = results.serverAddress;
+        ByteBuffer packet = DhcpPacket.buildRequestPacket(DhcpPacket.ENCAP_L2,
+                0 /* transactionId */, (short) 0 /* secs */, DhcpPacket.INADDR_ANY /* clientIp */,
+                false /* broadcast */, macAddress, clientIp /* requestedIpAddress */,
+                serverIdentifier, DHCP_REQUESTED_PARAMS, DHCP_HOSTNAME);
+        sendPacket(fd, packet);
+    }
+
+    private void sendPacket(FileDescriptor fd, ByteBuffer packet) throws Exception {
+        assertNotNull("Only tests on virtual interfaces can send packets", fd);
+        Os.write(fd, packet);
+    }
+
+    public void assertLinkAddressMatches(LinkAddress l1, LinkAddress l2) {
+        // Check all fields except the deprecation and expiry times.
+        String msg = String.format("LinkAddresses do not match. expected: %s actual: %s", l1, l2);
+        assertTrue(msg, l1.isSameAddressAs(l2));
+        assertEquals("LinkAddress flags do not match", l1.getFlags(), l2.getFlags());
+        assertEquals("LinkAddress scope does not match", l1.getScope(), l2.getScope());
+    }
+
+    private TetheringRequest requestWithStaticIpv4(String local, String client) {
+        LinkAddress localAddr = local == null ? null : new LinkAddress(local);
+        LinkAddress clientAddr = client == null ? null : new LinkAddress(client);
+        return new TetheringRequest.Builder(TETHERING_ETHERNET)
+                .setStaticIpv4Addresses(localAddr, clientAddr)
+                .setShouldShowEntitlementUi(false).build();
+    }
+
+    private void assertInvalidStaticIpv4Request(String iface, String local, String client)
+            throws Exception {
+        try {
+            enableEthernetTethering(iface, requestWithStaticIpv4(local, client));
+            fail("Unexpectedly accepted invalid IPv4 configuration: " + local + ", " + client);
+        } catch (IllegalArgumentException | NullPointerException expected) { }
+    }
+
+    private void assertInterfaceHasIpAddress(String iface, String expected) throws Exception {
+        LinkAddress expectedAddr = new LinkAddress(expected);
+        NetworkInterface nif = NetworkInterface.getByName(iface);
+        for (InterfaceAddress ia : nif.getInterfaceAddresses()) {
+            final LinkAddress addr = new LinkAddress(ia.getAddress(), ia.getNetworkPrefixLength());
+            if (expectedAddr.equals(addr)) {
+                return;
+            }
+        }
+        fail("Expected " + iface + " to have IP address " + expected + ", found "
+                + nif.getInterfaceAddresses());
+    }
+
+    private TestNetworkInterface createTestInterface() throws Exception {
+        TestNetworkManager tnm = mContext.getSystemService(TestNetworkManager.class);
+        TestNetworkInterface iface = tnm.createTapInterface();
+        Log.d(TAG, "Created test interface " + iface.getInterfaceName());
+        return iface;
+    }
+
+    private void maybeDeleteTestInterface() throws Exception {
+        if (mTestIface != null) {
+            mTestIface.getFileDescriptor().close();
+            Log.d(TAG, "Deleted test interface " + mTestIface.getInterfaceName());
+            mTestIface = null;
+        }
+    }
+}
diff --git a/Tethering/tests/jarjar-rules.txt b/Tethering/tests/jarjar-rules.txt
new file mode 100644
index 0000000..c99ff7f
--- /dev/null
+++ b/Tethering/tests/jarjar-rules.txt
@@ -0,0 +1,19 @@
+# Don't jar-jar the entire package because this test use some
+# internal classes (like ArrayUtils in com.android.internal.util)
+rule com.android.internal.util.BitUtils* com.android.networkstack.tethering.util.BitUtils@1
+rule com.android.internal.util.IndentingPrintWriter.java* com.android.networkstack.tethering.util.IndentingPrintWriter.java@1
+rule com.android.internal.util.IState.java* com.android.networkstack.tethering.util.IState.java@1
+rule com.android.internal.util.MessageUtils* com.android.networkstack.tethering.util.MessageUtils@1
+rule com.android.internal.util.State* com.android.networkstack.tethering.util.State@1
+rule com.android.internal.util.StateMachine* com.android.networkstack.tethering.util.StateMachine@1
+rule com.android.internal.util.TrafficStatsConstants* com.android.networkstack.tethering.util.TrafficStatsConstants@1
+
+rule android.util.LocalLog* com.android.networkstack.tethering.util.LocalLog@1
+
+# Classes from net-utils-framework-common
+rule com.android.net.module.util.** com.android.networkstack.tethering.util.@1
+
+# TODO: either stop using frameworks-base-testutils or remove the unit test classes it contains.
+# TestableLooper from "testables" can be used instead of TestLooper from frameworks-base-testutils.
+zap android.os.test.TestLooperTest*
+zap com.android.test.filters.SelectTestTests*
diff --git a/Tethering/tests/mts/Android.bp b/Tethering/tests/mts/Android.bp
new file mode 100644
index 0000000..f925b0a
--- /dev/null
+++ b/Tethering/tests/mts/Android.bp
@@ -0,0 +1,56 @@
+// Copyright (C) 2020 The Android Open Source Project
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//      http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+android_test {
+    // This tests for functionality that is not required for devices that
+    // don't use Tethering mainline module.
+    name: "MtsTetheringTest",
+
+    libs: [
+        "android.test.base",
+    ],
+
+    srcs: [
+        "src/**/*.java",
+    ],
+
+    static_libs: [
+        "androidx.test.rules",
+        // mockito-target-extended-minus-junit4 used in this lib have dependency with
+        // jni_libs libdexmakerjvmtiagent and libstaticjvmtiagent.
+        "cts-net-utils",
+        // This is needed for androidx.test.runner.AndroidJUnitRunner.
+        "ctstestrunner-axt",
+        "junit",
+        "junit-params",
+    ],
+
+    jni_libs: [
+        // For mockito extended which is pulled in from -net-utils -> net-tests-utils
+        // (mockito-target-extended-minus-junit4).
+        "libdexmakerjvmtiagent",
+        "libstaticjvmtiagent",
+    ],
+
+    platform_apis: true,
+
+    // Tag this module as a mts test artifact
+    test_suites: [
+        "general-tests",
+        "mts",
+    ],
+
+    // Include both the 32 and 64 bit versions
+    compile_multilib: "both",
+}
diff --git a/Tethering/tests/mts/AndroidManifest.xml b/Tethering/tests/mts/AndroidManifest.xml
new file mode 100644
index 0000000..6d2abca
--- /dev/null
+++ b/Tethering/tests/mts/AndroidManifest.xml
@@ -0,0 +1,34 @@
+<?xml version="1.0" encoding="utf-8"?>
+<!--
+ * Copyright (C) 2020 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ -->
+
+<manifest xmlns:android="http://schemas.android.com/apk/res/android"
+    package="android.tethering.mts">
+
+    <uses-permission android:name="android.permission.ACCESS_NETWORK_STATE" />
+    <uses-permission android:name="android.permission.INTERNET"/>
+
+    <application android:debuggable="true">
+        <uses-library android:name="android.test.runner" />
+    </application>
+    <instrumentation android:name="androidx.test.runner.AndroidJUnitRunner"
+                     android:targetPackage="android.tethering.mts"
+                     android:label="MTS tests of android.tethering">
+        <meta-data android:name="listener"
+            android:value="com.android.cts.runner.CtsTestRunListener" />
+    </instrumentation>
+
+</manifest>
diff --git a/Tethering/tests/mts/AndroidTest.xml b/Tethering/tests/mts/AndroidTest.xml
new file mode 100644
index 0000000..80788df
--- /dev/null
+++ b/Tethering/tests/mts/AndroidTest.xml
@@ -0,0 +1,36 @@
+<?xml version="1.0" encoding="utf-8"?>
+<!-- Copyright (C) 2019 The Android Open Source Project
+
+     Licensed under the Apache License, Version 2.0 (the "License");
+     you may not use this file except in compliance with the License.
+     You may obtain a copy of the License at
+
+          http://www.apache.org/licenses/LICENSE-2.0
+
+     Unless required by applicable law or agreed to in writing, software
+     distributed under the License is distributed on an "AS IS" BASIS,
+     WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+     See the License for the specific language governing permissions and
+     limitations under the License.
+-->
+<configuration description="Config for MTS Tethering test cases">
+    <option name="test-suite-tag" value="mts" />
+    <option name="config-descriptor:metadata" key="component" value="networking" />
+    <!-- Instant app do not have INTERNET permission. -->
+    <option name="config-descriptor:metadata" key="parameter" value="not_instant_app" />
+    <!-- Feature is not backed by native code. -->
+    <option name="config-descriptor:metadata" key="parameter" value="not_multi_abi" />
+    <!-- Allow running this against a secondary user. -->
+    <option name="config-descriptor:metadata" key="parameter" value="secondary_user" />
+    <target_preparer class="com.android.tradefed.targetprep.suite.SuiteApkInstaller">
+        <option name="cleanup-apks" value="true" />
+        <option name="test-file-name" value="MtsTetheringTest.apk" />
+    </target_preparer>
+    <test class="com.android.tradefed.testtype.AndroidJUnitTest" >
+        <option name="package" value="android.tethering.mts" />
+    </test>
+
+    <object type="module_controller" class="com.android.tradefed.testtype.suite.module.MainlineTestModuleController">
+        <option name="mainline-module-package-name" value="com.google.android.tethering" />
+    </object>
+</configuration>
diff --git a/Tethering/tests/mts/src/android/tethering/mts/TetheringModuleTest.java b/Tethering/tests/mts/src/android/tethering/mts/TetheringModuleTest.java
new file mode 100644
index 0000000..7ffe37a
--- /dev/null
+++ b/Tethering/tests/mts/src/android/tethering/mts/TetheringModuleTest.java
@@ -0,0 +1,183 @@
+/*
+ * Copyright (C) 2020 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package android.tethering.mts;
+
+import static android.Manifest.permission.MANAGE_TEST_NETWORKS;
+import static android.Manifest.permission.NETWORK_SETTINGS;
+import static android.Manifest.permission.READ_DEVICE_CONFIG;
+import static android.Manifest.permission.TETHER_PRIVILEGED;
+import static android.Manifest.permission.WRITE_SETTINGS;
+import static android.net.cts.util.CtsTetheringUtils.isWifiTetheringSupported;
+import static android.provider.DeviceConfig.NAMESPACE_CONNECTIVITY;
+
+import static com.android.testutils.TestNetworkTrackerKt.initTestNetwork;
+
+import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertFalse;
+import static org.junit.Assert.assertNotNull;
+import static org.junit.Assert.fail;
+import static org.junit.Assume.assumeTrue;
+
+import android.app.UiAutomation;
+import android.content.Context;
+import android.net.IpPrefix;
+import android.net.LinkAddress;
+import android.net.TetheringManager;
+import android.net.cts.util.CtsTetheringUtils;
+import android.net.cts.util.CtsTetheringUtils.TestTetheringEventCallback;
+import android.provider.DeviceConfig;
+
+import androidx.annotation.NonNull;
+import androidx.test.InstrumentationRegistry;
+import androidx.test.runner.AndroidJUnit4;
+
+import com.android.testutils.TestNetworkTracker;
+
+import org.junit.After;
+import org.junit.Before;
+import org.junit.Test;
+import org.junit.runner.RunWith;
+
+import java.net.InterfaceAddress;
+import java.net.NetworkInterface;
+import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.List;
+
+@RunWith(AndroidJUnit4.class)
+public class TetheringModuleTest {
+    private Context mContext;
+    private TetheringManager mTm;
+    private CtsTetheringUtils mCtsTetheringUtils;
+
+    private UiAutomation mUiAutomation =
+            InstrumentationRegistry.getInstrumentation().getUiAutomation();
+
+    @Before
+    public void setUp() throws Exception {
+        mUiAutomation.adoptShellPermissionIdentity(MANAGE_TEST_NETWORKS, NETWORK_SETTINGS,
+                WRITE_SETTINGS, READ_DEVICE_CONFIG, TETHER_PRIVILEGED);
+        mContext = InstrumentationRegistry.getContext();
+        mTm = mContext.getSystemService(TetheringManager.class);
+        mCtsTetheringUtils = new CtsTetheringUtils(mContext);
+    }
+
+    @After
+    public void tearDown() throws Exception {
+        mUiAutomation.dropShellPermissionIdentity();
+    }
+
+    private static final String TETHER_ENABLE_SELECT_ALL_PREFIX_RANGES =
+            "tether_enable_select_all_prefix_ranges";
+    @Test
+    public void testSwitchBasePrefixRangeWhenConflict() throws Exception {
+        assumeTrue(isFeatureEnabled(TETHER_ENABLE_SELECT_ALL_PREFIX_RANGES, true));
+
+        addressConflictTest(true);
+    }
+
+    @Test
+    public void testSwitchPrefixRangeWhenConflict() throws Exception {
+        addressConflictTest(false);
+    }
+
+    private void addressConflictTest(final boolean wholeRangeConflict) throws Exception {
+        final TestTetheringEventCallback tetherEventCallback =
+                mCtsTetheringUtils.registerTetheringEventCallback();
+
+        TestNetworkTracker tnt = null;
+        try {
+            tetherEventCallback.assumeTetheringSupported();
+            assumeTrue(isWifiTetheringSupported(tetherEventCallback));
+
+            mCtsTetheringUtils.startWifiTethering(tetherEventCallback);
+
+            final List<String> tetheredIfaces = tetherEventCallback.getTetheredInterfaces();
+            assertEquals(1, tetheredIfaces.size());
+            final String wifiTetheringIface = tetheredIfaces.get(0);
+
+            NetworkInterface nif = NetworkInterface.getByName(wifiTetheringIface);
+            // Tethering downstream only have one ipv4 address.
+            final LinkAddress hotspotAddr = getFirstIpv4Address(nif);
+            assertNotNull(hotspotAddr);
+
+            final IpPrefix testPrefix = getConflictingPrefix(hotspotAddr, wholeRangeConflict);
+            assertNotNull(testPrefix);
+
+            tnt = setUpTestNetwork(
+                    new LinkAddress(testPrefix.getAddress(), testPrefix.getPrefixLength()));
+
+            tetherEventCallback.expectTetheredInterfacesChanged(null);
+            final List<String> wifiRegexs =
+                    tetherEventCallback.getTetheringInterfaceRegexps().getTetherableWifiRegexs();
+
+            tetherEventCallback.expectTetheredInterfacesChanged(wifiRegexs);
+            nif = NetworkInterface.getByName(wifiTetheringIface);
+            final LinkAddress newHotspotAddr = getFirstIpv4Address(nif);
+            assertNotNull(newHotspotAddr);
+
+            assertFalse(testPrefix.containsPrefix(
+                    new IpPrefix(newHotspotAddr.getAddress(), newHotspotAddr.getPrefixLength())));
+
+            mCtsTetheringUtils.stopWifiTethering(tetherEventCallback);
+        } finally {
+            if (tnt != null) {
+                tnt.teardown();
+            }
+            mTm.stopAllTethering();
+            mCtsTetheringUtils.unregisterTetheringEventCallback(tetherEventCallback);
+        }
+    }
+
+    private LinkAddress getFirstIpv4Address(final NetworkInterface nif) {
+        for (InterfaceAddress ia : nif.getInterfaceAddresses()) {
+            final LinkAddress addr = new LinkAddress(ia.getAddress(), ia.getNetworkPrefixLength());
+            if (addr.isIpv4()) return addr;
+        }
+        return null;
+    }
+
+    @NonNull
+    private IpPrefix getConflictingPrefix(final LinkAddress address,
+            final boolean wholeRangeConflict) {
+        if (!wholeRangeConflict) {
+            return new IpPrefix(address.getAddress(), address.getPrefixLength());
+        }
+
+        final ArrayList<IpPrefix> prefixPool = new ArrayList<>(Arrays.asList(
+                new IpPrefix("192.168.0.0/16"),
+                new IpPrefix("172.16.0.0/12"),
+                new IpPrefix("10.0.0.0/8")));
+
+        for (IpPrefix prefix : prefixPool) {
+            if (prefix.contains(address.getAddress())) return prefix;
+        }
+
+        fail("Could not find sutiable conflict prefix");
+
+        // Never go here.
+        return null;
+    }
+
+    private TestNetworkTracker setUpTestNetwork(final LinkAddress address) throws Exception {
+        return initTestNetwork(mContext, address, 10_000L /* test timeout ms*/);
+
+    }
+
+    public static boolean isFeatureEnabled(final String name, final boolean defaultValue) {
+        return DeviceConfig.getBoolean(NAMESPACE_CONNECTIVITY, name, defaultValue);
+    }
+}
diff --git a/Tethering/tests/privileged/Android.bp b/Tethering/tests/privileged/Android.bp
new file mode 100644
index 0000000..9217345
--- /dev/null
+++ b/Tethering/tests/privileged/Android.bp
@@ -0,0 +1,49 @@
+//
+// Copyright (C) 2020 The Android Open Source Project
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//      http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+//
+
+java_defaults {
+    name: "TetheringPrivilegedTestsJniDefaults",
+    jni_libs: [
+        "libdexmakerjvmtiagent",
+        "libstaticjvmtiagent",
+        "libtetherutilsjni",
+    ],
+    jni_uses_sdk_apis: true,
+    visibility: ["//visibility:private"],
+}
+
+android_test {
+    name: "TetheringPrivilegedTests",
+    defaults: [
+        "TetheringPrivilegedTestsJniDefaults",
+    ],
+    srcs: [
+        "src/**/*.java",
+        "src/**/*.kt",
+    ],
+    certificate: "networkstack",
+    platform_apis: true,
+    test_suites: [
+        "device-tests",
+        "mts",
+    ],
+    static_libs: [
+        "androidx.test.rules",
+        "net-tests-utils",
+        "TetheringApiCurrentLib",
+    ],
+    compile_multilib: "both",
+}
diff --git a/Tethering/tests/privileged/AndroidManifest.xml b/Tethering/tests/privileged/AndroidManifest.xml
new file mode 100644
index 0000000..49eba15
--- /dev/null
+++ b/Tethering/tests/privileged/AndroidManifest.xml
@@ -0,0 +1,32 @@
+<?xml version="1.0" encoding="utf-8"?>
+<!-- Copyright (C) 2020 The Android Open Source Project
+
+     Licensed under the Apache License, Version 2.0 (the "License");
+     you may not use this file except in compliance with the License.
+     You may obtain a copy of the License at
+
+          http://www.apache.org/licenses/LICENSE-2.0
+
+     Unless required by applicable law or agreed to in writing, software
+     distributed under the License is distributed on an "AS IS" BASIS,
+     WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+     See the License for the specific language governing permissions and
+     limitations under the License.
+-->
+<manifest xmlns:android="http://schemas.android.com/apk/res/android"
+          package="com.android.networkstack.tethering.tests.privileged"
+          android:sharedUserId="android.uid.networkstack">
+
+    <!-- Note: do not add any privileged or signature permissions that are granted
+         to the network stack and its shared uid apps. Otherwise, the test APK will
+         install, but when the device is rebooted, it will bootloop because this
+         test APK is not in the privileged permission allow list -->
+
+    <application android:debuggable="true">
+        <uses-library android:name="android.test.runner" />
+    </application>
+    <instrumentation android:name="androidx.test.runner.AndroidJUnitRunner"
+        android:targetPackage="com.android.networkstack.tethering.tests.privileged"
+        android:label="Tethering privileged tests">
+    </instrumentation>
+</manifest>
diff --git a/Tethering/tests/privileged/src/android/net/ip/DadProxyTest.java b/Tethering/tests/privileged/src/android/net/ip/DadProxyTest.java
new file mode 100644
index 0000000..42a91aa
--- /dev/null
+++ b/Tethering/tests/privileged/src/android/net/ip/DadProxyTest.java
@@ -0,0 +1,276 @@
+/*
+ * Copyright (C) 2020 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package android.net.ip;
+
+import static android.system.OsConstants.IPPROTO_ICMPV6;
+
+import static com.android.net.module.util.IpUtils.icmpv6Checksum;
+import static com.android.net.module.util.NetworkStackConstants.ETHER_SRC_ADDR_OFFSET;
+
+import static org.junit.Assert.assertFalse;
+import static org.junit.Assert.assertNotNull;
+import static org.junit.Assert.assertTrue;
+
+import android.app.Instrumentation;
+import android.content.Context;
+import android.net.INetd;
+import android.net.InetAddresses;
+import android.net.MacAddress;
+import android.net.util.InterfaceParams;
+import android.net.util.TetheringUtils;
+import android.os.Handler;
+import android.os.HandlerThread;
+import android.os.IBinder;
+import android.os.Looper;
+
+import androidx.test.InstrumentationRegistry;
+import androidx.test.filters.SmallTest;
+import androidx.test.runner.AndroidJUnit4;
+
+import com.android.testutils.TapPacketReader;
+import com.android.testutils.TapPacketReaderRule;
+
+import org.junit.After;
+import org.junit.Before;
+import org.junit.BeforeClass;
+import org.junit.Rule;
+import org.junit.Test;
+import org.junit.runner.RunWith;
+import org.mockito.MockitoAnnotations;
+
+import java.nio.ByteBuffer;
+
+@RunWith(AndroidJUnit4.class)
+@SmallTest
+public class DadProxyTest {
+    private static final int DATA_BUFFER_LEN = 4096;
+    private static final int PACKET_TIMEOUT_MS = 5_000;
+
+    // Start the readers manually on a common handler shared with DadProxy, for simplicity
+    @Rule
+    public final TapPacketReaderRule mUpstreamReader = new TapPacketReaderRule(
+            DATA_BUFFER_LEN, false /* autoStart */);
+    @Rule
+    public final TapPacketReaderRule mTetheredReader = new TapPacketReaderRule(
+            DATA_BUFFER_LEN, false /* autoStart */);
+
+    private InterfaceParams mUpstreamParams, mTetheredParams;
+    private HandlerThread mHandlerThread;
+    private Handler mHandler;
+    private TapPacketReader mUpstreamPacketReader, mTetheredPacketReader;
+
+    private static INetd sNetd;
+
+    @BeforeClass
+    public static void setupOnce() {
+        System.loadLibrary("tetherutilsjni");
+
+        final Instrumentation inst = InstrumentationRegistry.getInstrumentation();
+        final IBinder netdIBinder =
+                (IBinder) inst.getContext().getSystemService(Context.NETD_SERVICE);
+        sNetd = INetd.Stub.asInterface(netdIBinder);
+    }
+
+    @Before
+    public void setUp() throws Exception {
+        MockitoAnnotations.initMocks(this);
+
+        mHandlerThread = new HandlerThread(getClass().getSimpleName());
+        mHandlerThread.start();
+        mHandler = new Handler(mHandlerThread.getLooper());
+
+        setupTapInterfaces();
+
+        // Looper must be prepared here since AndroidJUnitRunner runs tests on separate threads.
+        if (Looper.myLooper() == null) Looper.prepare();
+
+        DadProxy mProxy = setupProxy();
+    }
+
+    @After
+    public void tearDown() throws Exception {
+        mUpstreamReader.stop();
+        mTetheredReader.stop();
+
+        if (mHandlerThread != null) {
+            mHandlerThread.quitSafely();
+            mHandlerThread.join(PACKET_TIMEOUT_MS);
+        }
+
+        if (mTetheredParams != null) {
+            sNetd.networkRemoveInterface(INetd.LOCAL_NET_ID, mTetheredParams.name);
+        }
+        if (mUpstreamParams != null) {
+            sNetd.networkRemoveInterface(INetd.LOCAL_NET_ID, mUpstreamParams.name);
+        }
+    }
+
+    private void setupTapInterfaces() {
+        // Create upstream test iface.
+        mUpstreamReader.start(mHandler);
+        mUpstreamParams = InterfaceParams.getByName(mUpstreamReader.iface.getInterfaceName());
+        assertNotNull(mUpstreamParams);
+        mUpstreamPacketReader = mUpstreamReader.getReader();
+
+        // Create tethered test iface.
+        mTetheredReader.start(mHandler);
+        mTetheredParams = InterfaceParams.getByName(mTetheredReader.getIface().getInterfaceName());
+        assertNotNull(mTetheredParams);
+        mTetheredPacketReader = mTetheredReader.getReader();
+    }
+
+    private static final int IPV6_HEADER_LEN = 40;
+    private static final int ETH_HEADER_LEN = 14;
+    private static final int ICMPV6_NA_NS_LEN = 24;
+    private static final int LL_TARGET_OPTION_LEN = 8;
+    private static final int ICMPV6_CHECKSUM_OFFSET = 2;
+    private static final int ETHER_TYPE_IPV6 = 0x86dd;
+
+    private static ByteBuffer createDadPacket(int type) {
+        // Refer to buildArpPacket()
+        int icmpLen = ICMPV6_NA_NS_LEN
+                + (type == NeighborPacketForwarder.ICMPV6_NEIGHBOR_ADVERTISEMENT
+                ? LL_TARGET_OPTION_LEN : 0);
+        final ByteBuffer buf = ByteBuffer.allocate(icmpLen + IPV6_HEADER_LEN + ETH_HEADER_LEN);
+
+        // Ethernet header.
+        final MacAddress srcMac = MacAddress.fromString("33:33:ff:66:77:88");
+        buf.put(srcMac.toByteArray());
+        final MacAddress dstMac = MacAddress.fromString("01:02:03:04:05:06");
+        buf.put(dstMac.toByteArray());
+        buf.putShort((short) ETHER_TYPE_IPV6);
+
+        // IPv6 header
+        byte[] version = {(byte) 0x60, 0x00, 0x00, 0x00};
+        buf.put(version);                                           // Version
+        buf.putShort((byte) icmpLen);                               // Length
+        buf.put((byte) IPPROTO_ICMPV6);                             // Next header
+        buf.put((byte) 0xff);                                       // Hop limit
+
+        final byte[] target =
+            InetAddresses.parseNumericAddress("fe80::1122:3344:5566:7788").getAddress();
+        final byte[] src;
+        final byte[] dst;
+        if (type == NeighborPacketForwarder.ICMPV6_NEIGHBOR_SOLICITATION) {
+            src = InetAddresses.parseNumericAddress("::").getAddress();
+            dst = InetAddresses.parseNumericAddress("ff02::1:ff66:7788").getAddress();
+        } else {
+            src = target;
+            dst = TetheringUtils.ALL_NODES;
+        }
+        buf.put(src);
+        buf.put(dst);
+
+        // ICMPv6 Header
+        buf.put((byte) type);                                       // Type
+        buf.put((byte) 0x00);                                       // Code
+        buf.putShort((short) 0);                                    // Checksum
+        buf.putInt(0);                                              // Reserved
+        buf.put(target);
+
+        if (type == NeighborPacketForwarder.ICMPV6_NEIGHBOR_ADVERTISEMENT) {
+            //NA packet has LL target address
+            //ICMPv6 Option
+            buf.put((byte) 0x02);                                   // Type
+            buf.put((byte) 0x01);                                   // Length
+            byte[] ll_target = MacAddress.fromString("01:02:03:04:05:06").toByteArray();
+            buf.put(ll_target);
+        }
+
+        // Populate checksum field
+        final int transportOffset = ETH_HEADER_LEN + IPV6_HEADER_LEN;
+        final short checksum = icmpv6Checksum(buf, ETH_HEADER_LEN, transportOffset, icmpLen);
+        buf.putShort(transportOffset + ICMPV6_CHECKSUM_OFFSET, checksum);
+
+        buf.flip();
+        return buf;
+    }
+
+    private DadProxy setupProxy() throws Exception {
+        DadProxy proxy = new DadProxy(mHandler, mTetheredParams);
+        mHandler.post(() -> proxy.setUpstreamIface(mUpstreamParams));
+
+        // Upstream iface is added to local network to simplify test case.
+        // Otherwise the test needs to create and destroy a network for the upstream iface.
+        sNetd.networkAddInterface(INetd.LOCAL_NET_ID, mUpstreamParams.name);
+        sNetd.networkAddInterface(INetd.LOCAL_NET_ID, mTetheredParams.name);
+
+        return proxy;
+    }
+
+    // TODO: change to assert.
+    private boolean waitForPacket(ByteBuffer packet, TapPacketReader reader) {
+        byte[] p;
+
+        while ((p = reader.popPacket(PACKET_TIMEOUT_MS)) != null) {
+            final ByteBuffer buffer = ByteBuffer.wrap(p);
+
+            if (buffer.compareTo(packet) == 0) return true;
+        }
+        return false;
+    }
+
+    private void updateDstMac(ByteBuffer buf, MacAddress mac) {
+        buf.put(mac.toByteArray());
+        buf.rewind();
+    }
+    private void updateSrcMac(ByteBuffer buf, InterfaceParams ifaceParams) {
+        buf.position(ETHER_SRC_ADDR_OFFSET);
+        buf.put(ifaceParams.macAddr.toByteArray());
+        buf.rewind();
+    }
+
+    @Test
+    public void testNaForwardingFromUpstreamToTether() throws Exception {
+        ByteBuffer na = createDadPacket(NeighborPacketForwarder.ICMPV6_NEIGHBOR_ADVERTISEMENT);
+
+        mUpstreamPacketReader.sendResponse(na);
+        updateDstMac(na, MacAddress.fromString("33:33:00:00:00:01"));
+        updateSrcMac(na, mTetheredParams);
+        assertTrue(waitForPacket(na, mTetheredPacketReader));
+    }
+
+    @Test
+    // TODO: remove test once DAD works in both directions.
+    public void testNaForwardingFromTetherToUpstream() throws Exception {
+        ByteBuffer na = createDadPacket(NeighborPacketForwarder.ICMPV6_NEIGHBOR_ADVERTISEMENT);
+
+        mTetheredPacketReader.sendResponse(na);
+        updateDstMac(na, MacAddress.fromString("33:33:00:00:00:01"));
+        updateSrcMac(na, mTetheredParams);
+        assertFalse(waitForPacket(na, mUpstreamPacketReader));
+    }
+
+    @Test
+    public void testNsForwardingFromTetherToUpstream() throws Exception {
+        ByteBuffer ns = createDadPacket(NeighborPacketForwarder.ICMPV6_NEIGHBOR_SOLICITATION);
+
+        mTetheredPacketReader.sendResponse(ns);
+        updateSrcMac(ns, mUpstreamParams);
+        assertTrue(waitForPacket(ns, mUpstreamPacketReader));
+    }
+
+    @Test
+    // TODO: remove test once DAD works in both directions.
+    public void testNsForwardingFromUpstreamToTether() throws Exception {
+        ByteBuffer ns = createDadPacket(NeighborPacketForwarder.ICMPV6_NEIGHBOR_SOLICITATION);
+
+        mUpstreamPacketReader.sendResponse(ns);
+        updateSrcMac(ns, mUpstreamParams);
+        assertFalse(waitForPacket(ns, mTetheredPacketReader));
+    }
+}
diff --git a/Tethering/tests/privileged/src/com/android/networkstack/tethering/ConntrackSocketTest.java b/Tethering/tests/privileged/src/com/android/networkstack/tethering/ConntrackSocketTest.java
new file mode 100644
index 0000000..57c28fc
--- /dev/null
+++ b/Tethering/tests/privileged/src/com/android/networkstack/tethering/ConntrackSocketTest.java
@@ -0,0 +1,130 @@
+/*
+ * Copyright (C) 2020 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.android.networkstack.tethering;
+
+import static android.net.netlink.NetlinkSocket.DEFAULT_RECV_BUFSIZE;
+import static android.net.netlink.StructNlMsgHdr.NLM_F_DUMP;
+import static android.net.netlink.StructNlMsgHdr.NLM_F_REQUEST;
+
+import static com.android.networkstack.tethering.OffloadHardwareInterface.IPCTNL_MSG_CT_GET;
+import static com.android.networkstack.tethering.OffloadHardwareInterface.IPCTNL_MSG_CT_NEW;
+import static com.android.networkstack.tethering.OffloadHardwareInterface.NFNL_SUBSYS_CTNETLINK;
+import static com.android.networkstack.tethering.OffloadHardwareInterface.NF_NETLINK_CONNTRACK_DESTROY;
+import static com.android.networkstack.tethering.OffloadHardwareInterface.NF_NETLINK_CONNTRACK_NEW;
+
+import static org.junit.Assert.assertNotNull;
+import static org.junit.Assert.assertTrue;
+
+import android.net.netlink.StructNlMsgHdr;
+import android.net.util.SharedLog;
+import android.os.Handler;
+import android.os.HandlerThread;
+import android.os.Looper;
+import android.os.NativeHandle;
+import android.system.Os;
+
+import androidx.test.filters.SmallTest;
+import androidx.test.runner.AndroidJUnit4;
+
+import org.junit.Before;
+import org.junit.Test;
+import org.junit.runner.RunWith;
+import org.mockito.MockitoAnnotations;
+
+import java.net.InetAddress;
+import java.net.InetSocketAddress;
+import java.net.ServerSocket;
+import java.net.Socket;
+import java.net.SocketAddress;
+import java.nio.ByteBuffer;
+import java.nio.ByteOrder;
+
+@RunWith(AndroidJUnit4.class)
+@SmallTest
+public class ConntrackSocketTest {
+    private static final long TIMEOUT = 500;
+
+    private HandlerThread mHandlerThread;
+    private Handler mHandler;
+    private final SharedLog mLog = new SharedLog("privileged-test");
+
+    private OffloadHardwareInterface mOffloadHw;
+    private OffloadHardwareInterface.Dependencies mDeps;
+
+    @Before
+    public void setUp() throws Exception {
+        MockitoAnnotations.initMocks(this);
+
+        mHandlerThread = new HandlerThread(getClass().getSimpleName());
+        mHandlerThread.start();
+        mHandler = new Handler(mHandlerThread.getLooper());
+
+        // Looper must be prepared here since AndroidJUnitRunner runs tests on separate threads.
+        if (Looper.myLooper() == null) Looper.prepare();
+
+        mDeps = new OffloadHardwareInterface.Dependencies(mLog);
+        mOffloadHw = new OffloadHardwareInterface(mHandler, mLog, mDeps);
+    }
+
+    @Test
+    public void testIpv4ConntrackSocket() throws Exception {
+        // Set up server and connect.
+        final InetSocketAddress anyAddress = new InetSocketAddress(
+                InetAddress.getByName("127.0.0.1"), 0);
+        final ServerSocket serverSocket = new ServerSocket();
+        serverSocket.bind(anyAddress);
+        final SocketAddress theAddress = serverSocket.getLocalSocketAddress();
+
+        // Make a connection to the server.
+        final Socket socket = new Socket();
+        socket.connect(theAddress);
+        final Socket acceptedSocket = serverSocket.accept();
+
+        final NativeHandle handle = mDeps.createConntrackSocket(
+                NF_NETLINK_CONNTRACK_NEW | NF_NETLINK_CONNTRACK_DESTROY);
+        mOffloadHw.sendIpv4NfGenMsg(handle,
+                (short) ((NFNL_SUBSYS_CTNETLINK << 8) | IPCTNL_MSG_CT_GET),
+                (short) (NLM_F_REQUEST | NLM_F_DUMP));
+
+        boolean foundConntrackEntry = false;
+        ByteBuffer buffer = ByteBuffer.allocate(DEFAULT_RECV_BUFSIZE);
+        buffer.order(ByteOrder.nativeOrder());
+
+        try {
+            while (Os.read(handle.getFileDescriptor(), buffer) > 0) {
+                buffer.flip();
+
+                // TODO: ConntrackMessage should get a parse API like StructNlMsgHdr
+                // so we can confirm that the conntrack added is for the TCP connection above.
+                final StructNlMsgHdr nlmsghdr = StructNlMsgHdr.parse(buffer);
+                assertNotNull(nlmsghdr);
+
+                // As long as 1 conntrack entry is found test case will pass, even if it's not
+                // the from the TCP connection above.
+                if (nlmsghdr.nlmsg_type == ((NFNL_SUBSYS_CTNETLINK << 8) | IPCTNL_MSG_CT_NEW)) {
+                    foundConntrackEntry = true;
+                    break;
+                }
+            }
+        } finally {
+            socket.close();
+            serverSocket.close();
+        }
+        assertTrue("Did not receive any NFNL_SUBSYS_CTNETLINK/IPCTNL_MSG_CT_NEW message",
+                foundConntrackEntry);
+    }
+}
diff --git a/Tethering/tests/unit/Android.bp b/Tethering/tests/unit/Android.bp
new file mode 100644
index 0000000..956e2e8
--- /dev/null
+++ b/Tethering/tests/unit/Android.bp
@@ -0,0 +1,94 @@
+//
+// Copyright (C) 2019 The Android Open Source Project
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//      http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+//
+
+// Tests in this folder are included both in unit tests and CTS.
+java_library {
+    name: "TetheringCommonTests",
+    srcs: [
+        "common/**/*.java",
+        "common/**/*.kt"
+    ],
+    static_libs: [
+        "androidx.test.rules",
+        "net-tests-utils",
+    ],
+    // TODO(b/147200698) change sdk_version to module-current and remove framework-minus-apex
+    sdk_version: "core_platform",
+    libs: [
+        "framework-minus-apex",
+        "framework-tethering.impl",
+    ],
+    visibility: ["//cts/tests/tests/tethering"],
+}
+
+java_defaults {
+    name: "TetheringTestsDefaults",
+    srcs: [
+        "src/**/*.java",
+        "src/**/*.kt",
+    ],
+    static_libs: [
+        "TetheringApiCurrentLib",
+        "TetheringCommonTests",
+        "androidx.test.rules",
+        "frameworks-base-testutils",
+        "mockito-target-extended-minus-junit4",
+        "net-tests-utils",
+        "testables",
+    ],
+    // TODO(b/147200698) change sdk_version to module-current and
+    // remove framework-minus-apex, ext, and framework-res
+    sdk_version: "core_platform",
+    libs: [
+        "android.test.runner",
+        "android.test.base",
+        "android.test.mock",
+        "ext",
+        "framework-minus-apex",
+        "framework-res",
+        "framework-tethering.impl",
+        "framework-wifi.stubs.module_lib",
+    ],
+    jni_libs: [
+        // For mockito extended
+        "libdexmakerjvmtiagent",
+        "libstaticjvmtiagent",
+    ],
+}
+
+// Library containing the unit tests. This is used by the coverage test target to pull in the
+// unit test code. It is not currently used by the tests themselves because all the build
+// configuration needed by the tests is in the TetheringTestsDefaults rule.
+android_library {
+    name: "TetheringTestsLib",
+    defaults: ["TetheringTestsDefaults"],
+    visibility: [
+        "//frameworks/base/packages/Tethering/tests/integration",
+        "//packages/modules/Connectivity/Tethering/tests/integration",
+    ]
+}
+
+android_test {
+    name: "TetheringTests",
+    platform_apis: true,
+    test_suites: [
+        "device-tests",
+        "mts",
+    ],
+    jarjar_rules: ":TetheringTestsJarJarRules",
+    defaults: ["TetheringTestsDefaults"],
+    compile_multilib: "both",
+}
diff --git a/Tethering/tests/unit/AndroidManifest.xml b/Tethering/tests/unit/AndroidManifest.xml
new file mode 100644
index 0000000..355342f
--- /dev/null
+++ b/Tethering/tests/unit/AndroidManifest.xml
@@ -0,0 +1,35 @@
+<?xml version="1.0" encoding="utf-8"?>
+<!-- Copyright (C) 2019 The Android Open Source Project
+
+     Licensed under the Apache License, Version 2.0 (the "License");
+     you may not use this file except in compliance with the License.
+     You may obtain a copy of the License at
+
+          http://www.apache.org/licenses/LICENSE-2.0
+
+     Unless required by applicable law or agreed to in writing, software
+     distributed under the License is distributed on an "AS IS" BASIS,
+     WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+     See the License for the specific language governing permissions and
+     limitations under the License.
+-->
+<manifest xmlns:android="http://schemas.android.com/apk/res/android"
+          package="com.android.networkstack.tethering.tests.unit">
+
+    <application android:debuggable="true">
+        <uses-library android:name="android.test.runner" />
+        <service
+            android:name="com.android.networkstack.tethering.MockTetheringService"
+            android:permission="android.permission.TETHER_PRIVILEGED"
+            android:exported="true">
+            <intent-filter>
+                <action android:name="com.android.networkstack.tethering.TetheringService"/>
+            </intent-filter>
+        </service>
+    </application>
+
+    <instrumentation android:name="androidx.test.runner.AndroidJUnitRunner"
+        android:targetPackage="com.android.networkstack.tethering.tests.unit"
+        android:label="Tethering service tests">
+    </instrumentation>
+</manifest>
diff --git a/Tethering/tests/unit/common/android/net/TetheredClientTest.kt b/Tethering/tests/unit/common/android/net/TetheredClientTest.kt
new file mode 100644
index 0000000..55c59dd
--- /dev/null
+++ b/Tethering/tests/unit/common/android/net/TetheredClientTest.kt
@@ -0,0 +1,122 @@
+/*
+ * Copyright (C) 2020 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package android.net
+
+import android.net.InetAddresses.parseNumericAddress
+import android.net.TetheredClient.AddressInfo
+import android.net.TetheringManager.TETHERING_BLUETOOTH
+import android.net.TetheringManager.TETHERING_USB
+import android.system.OsConstants.RT_SCOPE_UNIVERSE
+import androidx.test.filters.SmallTest
+import androidx.test.runner.AndroidJUnit4
+import com.android.testutils.assertParcelSane
+import org.junit.Test
+import org.junit.runner.RunWith
+import kotlin.test.assertEquals
+import kotlin.test.assertNotEquals
+
+private val TEST_MACADDR = MacAddress.fromBytes(byteArrayOf(12, 23, 34, 45, 56, 67))
+private val TEST_OTHER_MACADDR = MacAddress.fromBytes(byteArrayOf(23, 34, 45, 56, 67, 78))
+private val TEST_ADDR1 = makeLinkAddress("192.168.113.3", prefixLength = 24, expTime = 123L)
+private val TEST_ADDR2 = makeLinkAddress("fe80::1:2:3", prefixLength = 64, expTime = 456L)
+private val TEST_HOSTNAME = "test_hostname"
+private val TEST_OTHER_HOSTNAME = "test_other_hostname"
+private val TEST_ADDRINFO1 = AddressInfo(TEST_ADDR1, TEST_HOSTNAME)
+private val TEST_ADDRINFO2 = AddressInfo(TEST_ADDR2, null)
+
+private fun makeLinkAddress(addr: String, prefixLength: Int, expTime: Long) = LinkAddress(
+        parseNumericAddress(addr),
+        prefixLength,
+        0 /* flags */,
+        RT_SCOPE_UNIVERSE,
+        expTime /* deprecationTime */,
+        expTime /* expirationTime */)
+
+@RunWith(AndroidJUnit4::class)
+@SmallTest
+class TetheredClientTest {
+    @Test
+    fun testParceling() {
+        assertParcelSane(TEST_ADDRINFO1, fieldCount = 2)
+        assertParcelSane(makeTestClient(), fieldCount = 3)
+    }
+
+    @Test
+    fun testEquals() {
+        assertEquals(makeTestClient(), makeTestClient())
+
+        // Different mac address
+        assertNotEquals(makeTestClient(), TetheredClient(
+                TEST_OTHER_MACADDR,
+                listOf(TEST_ADDRINFO1, TEST_ADDRINFO2),
+                TETHERING_BLUETOOTH))
+
+        // Different hostname
+        assertNotEquals(makeTestClient(), TetheredClient(
+                TEST_MACADDR,
+                listOf(AddressInfo(TEST_ADDR1, TEST_OTHER_HOSTNAME), TEST_ADDRINFO2),
+                TETHERING_BLUETOOTH))
+
+        // Null hostname
+        assertNotEquals(makeTestClient(), TetheredClient(
+                TEST_MACADDR,
+                listOf(AddressInfo(TEST_ADDR1, null), TEST_ADDRINFO2),
+                TETHERING_BLUETOOTH))
+
+        // Missing address
+        assertNotEquals(makeTestClient(), TetheredClient(
+                TEST_MACADDR,
+                listOf(TEST_ADDRINFO2),
+                TETHERING_BLUETOOTH))
+
+        // Different type
+        assertNotEquals(makeTestClient(), TetheredClient(
+                TEST_MACADDR,
+                listOf(TEST_ADDRINFO1, TEST_ADDRINFO2),
+                TETHERING_USB))
+    }
+
+    @Test
+    fun testAddAddresses() {
+        val client1 = TetheredClient(TEST_MACADDR, listOf(TEST_ADDRINFO1), TETHERING_USB)
+        val client2 = TetheredClient(TEST_OTHER_MACADDR, listOf(TEST_ADDRINFO2), TETHERING_USB)
+        assertEquals(TetheredClient(
+                TEST_MACADDR,
+                listOf(TEST_ADDRINFO1, TEST_ADDRINFO2),
+                TETHERING_USB), client1.addAddresses(client2))
+    }
+
+    @Test
+    fun testGetters() {
+        assertEquals(TEST_MACADDR, makeTestClient().macAddress)
+        assertEquals(listOf(TEST_ADDRINFO1, TEST_ADDRINFO2), makeTestClient().addresses)
+        assertEquals(TETHERING_BLUETOOTH, makeTestClient().tetheringType)
+    }
+
+    @Test
+    fun testAddressInfo_Getters() {
+        assertEquals(TEST_ADDR1, TEST_ADDRINFO1.address)
+        assertEquals(TEST_ADDR2, TEST_ADDRINFO2.address)
+        assertEquals(TEST_HOSTNAME, TEST_ADDRINFO1.hostname)
+        assertEquals(null, TEST_ADDRINFO2.hostname)
+    }
+
+    private fun makeTestClient() = TetheredClient(
+            TEST_MACADDR,
+            listOf(TEST_ADDRINFO1, TEST_ADDRINFO2),
+            TETHERING_BLUETOOTH)
+}
\ No newline at end of file
diff --git a/Tethering/tests/unit/src/android/net/dhcp/DhcpServingParamsParcelExtTest.java b/Tethering/tests/unit/src/android/net/dhcp/DhcpServingParamsParcelExtTest.java
new file mode 100644
index 0000000..a8857b2
--- /dev/null
+++ b/Tethering/tests/unit/src/android/net/dhcp/DhcpServingParamsParcelExtTest.java
@@ -0,0 +1,123 @@
+/*
+ * Copyright (C) 2018 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package android.net.dhcp;
+
+import static android.net.InetAddresses.parseNumericAddress;
+
+import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertFalse;
+import static org.junit.Assert.assertTrue;
+
+import android.net.LinkAddress;
+
+import androidx.test.filters.SmallTest;
+import androidx.test.runner.AndroidJUnit4;
+
+import org.junit.Before;
+import org.junit.Test;
+import org.junit.runner.RunWith;
+
+import java.net.Inet4Address;
+import java.util.Arrays;
+import java.util.HashSet;
+import java.util.Set;
+import java.util.stream.Collectors;
+import java.util.stream.IntStream;
+
+@RunWith(AndroidJUnit4.class)
+@SmallTest
+public class DhcpServingParamsParcelExtTest {
+    private static final Inet4Address TEST_ADDRESS = inet4Addr("192.168.0.123");
+    private static final Inet4Address TEST_CLIENT_ADDRESS = inet4Addr("192.168.0.42");
+    private static final int TEST_ADDRESS_PARCELED = 0xc0a8007b;
+    private static final int TEST_CLIENT_ADDRESS_PARCELED = 0xc0a8002a;
+    private static final int TEST_PREFIX_LENGTH = 17;
+    private static final int TEST_LEASE_TIME_SECS = 120;
+    private static final int TEST_MTU = 1000;
+    private static final Set<Inet4Address> TEST_ADDRESS_SET =
+            new HashSet<Inet4Address>(Arrays.asList(
+            new Inet4Address[] {inet4Addr("192.168.1.123"), inet4Addr("192.168.1.124")}));
+    private static final Set<Integer> TEST_ADDRESS_SET_PARCELED =
+            new HashSet<Integer>(Arrays.asList(new Integer[] {0xc0a8017b, 0xc0a8017c}));
+
+    private DhcpServingParamsParcelExt mParcel;
+
+    @Before
+    public void setUp() {
+        mParcel = new DhcpServingParamsParcelExt();
+    }
+
+    @Test
+    public void testSetServerAddr() {
+        mParcel.setServerAddr(new LinkAddress(TEST_ADDRESS, TEST_PREFIX_LENGTH));
+
+        assertEquals(TEST_ADDRESS_PARCELED, mParcel.serverAddr);
+        assertEquals(TEST_PREFIX_LENGTH, mParcel.serverAddrPrefixLength);
+    }
+
+    @Test
+    public void testSetDefaultRouters() {
+        mParcel.setDefaultRouters(TEST_ADDRESS_SET);
+        assertEquals(TEST_ADDRESS_SET_PARCELED, asSet(mParcel.defaultRouters));
+    }
+
+    @Test
+    public void testSetDnsServers() {
+        mParcel.setDnsServers(TEST_ADDRESS_SET);
+        assertEquals(TEST_ADDRESS_SET_PARCELED, asSet(mParcel.dnsServers));
+    }
+
+    @Test
+    public void testSetExcludedAddrs() {
+        mParcel.setExcludedAddrs(TEST_ADDRESS_SET);
+        assertEquals(TEST_ADDRESS_SET_PARCELED, asSet(mParcel.excludedAddrs));
+    }
+
+    @Test
+    public void testSetDhcpLeaseTimeSecs() {
+        mParcel.setDhcpLeaseTimeSecs(TEST_LEASE_TIME_SECS);
+        assertEquals(TEST_LEASE_TIME_SECS, mParcel.dhcpLeaseTimeSecs);
+    }
+
+    @Test
+    public void testSetLinkMtu() {
+        mParcel.setLinkMtu(TEST_MTU);
+        assertEquals(TEST_MTU, mParcel.linkMtu);
+    }
+
+    @Test
+    public void testSetMetered() {
+        mParcel.setMetered(true);
+        assertTrue(mParcel.metered);
+        mParcel.setMetered(false);
+        assertFalse(mParcel.metered);
+    }
+
+    @Test
+    public void testSetClientAddr() {
+        mParcel.setSingleClientAddr(TEST_CLIENT_ADDRESS);
+        assertEquals(TEST_CLIENT_ADDRESS_PARCELED, mParcel.singleClientAddr);
+    }
+
+    private static Inet4Address inet4Addr(String addr) {
+        return (Inet4Address) parseNumericAddress(addr);
+    }
+
+    private static Set<Integer> asSet(int[] ints) {
+        return IntStream.of(ints).boxed().collect(Collectors.toSet());
+    }
+}
diff --git a/Tethering/tests/unit/src/android/net/ip/IpServerTest.java b/Tethering/tests/unit/src/android/net/ip/IpServerTest.java
new file mode 100644
index 0000000..2eb7589
--- /dev/null
+++ b/Tethering/tests/unit/src/android/net/ip/IpServerTest.java
@@ -0,0 +1,1201 @@
+/*
+ * Copyright (C) 2016 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package android.net.ip;
+
+import static android.net.INetd.IF_STATE_UP;
+import static android.net.RouteInfo.RTN_UNICAST;
+import static android.net.TetheringManager.TETHERING_BLUETOOTH;
+import static android.net.TetheringManager.TETHERING_NCM;
+import static android.net.TetheringManager.TETHERING_USB;
+import static android.net.TetheringManager.TETHERING_WIFI;
+import static android.net.TetheringManager.TETHERING_WIFI_P2P;
+import static android.net.TetheringManager.TETHER_ERROR_ENABLE_FORWARDING_ERROR;
+import static android.net.TetheringManager.TETHER_ERROR_NO_ERROR;
+import static android.net.TetheringManager.TETHER_ERROR_TETHER_IFACE_ERROR;
+import static android.net.dhcp.IDhcpServer.STATUS_SUCCESS;
+import static android.net.ip.IpServer.STATE_AVAILABLE;
+import static android.net.ip.IpServer.STATE_LOCAL_ONLY;
+import static android.net.ip.IpServer.STATE_TETHERED;
+import static android.net.ip.IpServer.STATE_UNAVAILABLE;
+import static android.net.netlink.NetlinkConstants.RTM_DELNEIGH;
+import static android.net.netlink.NetlinkConstants.RTM_NEWNEIGH;
+import static android.net.netlink.StructNdMsg.NUD_FAILED;
+import static android.net.netlink.StructNdMsg.NUD_REACHABLE;
+import static android.net.netlink.StructNdMsg.NUD_STALE;
+
+import static com.android.net.module.util.Inet4AddressUtils.intToInet4AddressHTH;
+
+import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertFalse;
+import static org.junit.Assert.assertNotEquals;
+import static org.junit.Assert.assertNotNull;
+import static org.junit.Assert.assertTrue;
+import static org.junit.Assert.fail;
+import static org.mockito.ArgumentMatchers.argThat;
+import static org.mockito.Matchers.any;
+import static org.mockito.Matchers.anyBoolean;
+import static org.mockito.Matchers.anyString;
+import static org.mockito.Matchers.eq;
+import static org.mockito.Mockito.doAnswer;
+import static org.mockito.Mockito.doNothing;
+import static org.mockito.Mockito.doReturn;
+import static org.mockito.Mockito.doThrow;
+import static org.mockito.Mockito.inOrder;
+import static org.mockito.Mockito.never;
+import static org.mockito.Mockito.reset;
+import static org.mockito.Mockito.spy;
+import static org.mockito.Mockito.timeout;
+import static org.mockito.Mockito.times;
+import static org.mockito.Mockito.verify;
+import static org.mockito.Mockito.verifyNoMoreInteractions;
+import static org.mockito.Mockito.when;
+
+import android.app.usage.NetworkStatsManager;
+import android.net.INetd;
+import android.net.InetAddresses;
+import android.net.InterfaceConfigurationParcel;
+import android.net.IpPrefix;
+import android.net.LinkAddress;
+import android.net.LinkProperties;
+import android.net.MacAddress;
+import android.net.RouteInfo;
+import android.net.TetherOffloadRuleParcel;
+import android.net.TetherStatsParcel;
+import android.net.dhcp.DhcpServerCallbacks;
+import android.net.dhcp.DhcpServingParamsParcel;
+import android.net.dhcp.IDhcpEventCallbacks;
+import android.net.dhcp.IDhcpServer;
+import android.net.dhcp.IDhcpServerCallbacks;
+import android.net.ip.IpNeighborMonitor.NeighborEvent;
+import android.net.ip.IpNeighborMonitor.NeighborEventConsumer;
+import android.net.ip.RouterAdvertisementDaemon.RaParams;
+import android.net.util.InterfaceParams;
+import android.net.util.InterfaceSet;
+import android.net.util.PrefixUtils;
+import android.net.util.SharedLog;
+import android.os.Build;
+import android.os.Handler;
+import android.os.RemoteException;
+import android.os.test.TestLooper;
+import android.text.TextUtils;
+
+import androidx.annotation.NonNull;
+import androidx.annotation.Nullable;
+import androidx.test.filters.SmallTest;
+import androidx.test.runner.AndroidJUnit4;
+
+import com.android.networkstack.tethering.BpfCoordinator;
+import com.android.networkstack.tethering.BpfCoordinator.Ipv6ForwardingRule;
+import com.android.networkstack.tethering.PrivateAddressCoordinator;
+import com.android.networkstack.tethering.TetheringConfiguration;
+import com.android.testutils.DevSdkIgnoreRule;
+import com.android.testutils.DevSdkIgnoreRule.IgnoreAfter;
+import com.android.testutils.DevSdkIgnoreRule.IgnoreUpTo;
+
+import org.junit.Before;
+import org.junit.Rule;
+import org.junit.Test;
+import org.junit.runner.RunWith;
+import org.mockito.ArgumentCaptor;
+import org.mockito.ArgumentMatcher;
+import org.mockito.Captor;
+import org.mockito.InOrder;
+import org.mockito.Mock;
+import org.mockito.MockitoAnnotations;
+
+import java.net.Inet4Address;
+import java.net.Inet6Address;
+import java.net.InetAddress;
+import java.util.Arrays;
+import java.util.List;
+
+@RunWith(AndroidJUnit4.class)
+@SmallTest
+public class IpServerTest {
+    @Rule
+    public final DevSdkIgnoreRule mIgnoreRule = new DevSdkIgnoreRule();
+
+    private static final String IFACE_NAME = "testnet1";
+    private static final String UPSTREAM_IFACE = "upstream0";
+    private static final String UPSTREAM_IFACE2 = "upstream1";
+    private static final int UPSTREAM_IFINDEX = 101;
+    private static final int UPSTREAM_IFINDEX2 = 102;
+    private static final String BLUETOOTH_IFACE_ADDR = "192.168.44.1";
+    private static final int BLUETOOTH_DHCP_PREFIX_LENGTH = 24;
+    private static final int DHCP_LEASE_TIME_SECS = 3600;
+    private static final boolean DEFAULT_USING_BPF_OFFLOAD = true;
+
+    private static final InterfaceParams TEST_IFACE_PARAMS = new InterfaceParams(
+            IFACE_NAME, 42 /* index */, MacAddress.ALL_ZEROS_ADDRESS, 1500 /* defaultMtu */);
+    private static final InterfaceParams UPSTREAM_IFACE_PARAMS = new InterfaceParams(
+            UPSTREAM_IFACE, UPSTREAM_IFINDEX, MacAddress.ALL_ZEROS_ADDRESS, 1500 /* defaultMtu */);
+    private static final InterfaceParams UPSTREAM_IFACE_PARAMS2 = new InterfaceParams(
+            UPSTREAM_IFACE2, UPSTREAM_IFINDEX2, MacAddress.ALL_ZEROS_ADDRESS,
+            1500 /* defaultMtu */);
+
+    private static final int MAKE_DHCPSERVER_TIMEOUT_MS = 1000;
+
+    private final LinkAddress mTestAddress = new LinkAddress("192.168.42.5/24");
+    private final IpPrefix mBluetoothPrefix = new IpPrefix("192.168.44.0/24");
+
+    @Mock private INetd mNetd;
+    @Mock private IpServer.Callback mCallback;
+    @Mock private SharedLog mSharedLog;
+    @Mock private IDhcpServer mDhcpServer;
+    @Mock private DadProxy mDadProxy;
+    @Mock private RouterAdvertisementDaemon mRaDaemon;
+    @Mock private IpNeighborMonitor mIpNeighborMonitor;
+    @Mock private IpServer.Dependencies mDependencies;
+    @Mock private PrivateAddressCoordinator mAddressCoordinator;
+    @Mock private NetworkStatsManager mStatsManager;
+    @Mock private TetheringConfiguration mTetherConfig;
+
+    @Captor private ArgumentCaptor<DhcpServingParamsParcel> mDhcpParamsCaptor;
+
+    private final TestLooper mLooper = new TestLooper();
+    private final ArgumentCaptor<LinkProperties> mLinkPropertiesCaptor =
+            ArgumentCaptor.forClass(LinkProperties.class);
+    private IpServer mIpServer;
+    private InterfaceConfigurationParcel mInterfaceConfiguration;
+    private NeighborEventConsumer mNeighborEventConsumer;
+    private BpfCoordinator mBpfCoordinator;
+
+    private void initStateMachine(int interfaceType) throws Exception {
+        initStateMachine(interfaceType, false /* usingLegacyDhcp */, DEFAULT_USING_BPF_OFFLOAD);
+    }
+
+    private void initStateMachine(int interfaceType, boolean usingLegacyDhcp,
+            boolean usingBpfOffload) throws Exception {
+        when(mDependencies.getDadProxy(any(), any())).thenReturn(mDadProxy);
+        when(mDependencies.getRouterAdvertisementDaemon(any())).thenReturn(mRaDaemon);
+        when(mDependencies.getInterfaceParams(IFACE_NAME)).thenReturn(TEST_IFACE_PARAMS);
+        when(mDependencies.getInterfaceParams(UPSTREAM_IFACE)).thenReturn(UPSTREAM_IFACE_PARAMS);
+        when(mDependencies.getInterfaceParams(UPSTREAM_IFACE2)).thenReturn(UPSTREAM_IFACE_PARAMS2);
+
+        when(mDependencies.getIfindex(eq(UPSTREAM_IFACE))).thenReturn(UPSTREAM_IFINDEX);
+        when(mDependencies.getIfindex(eq(UPSTREAM_IFACE2))).thenReturn(UPSTREAM_IFINDEX2);
+
+        mInterfaceConfiguration = new InterfaceConfigurationParcel();
+        mInterfaceConfiguration.flags = new String[0];
+        if (interfaceType == TETHERING_BLUETOOTH) {
+            mInterfaceConfiguration.ipv4Addr = BLUETOOTH_IFACE_ADDR;
+            mInterfaceConfiguration.prefixLength = BLUETOOTH_DHCP_PREFIX_LENGTH;
+        }
+
+        ArgumentCaptor<NeighborEventConsumer> neighborCaptor =
+                ArgumentCaptor.forClass(NeighborEventConsumer.class);
+        doReturn(mIpNeighborMonitor).when(mDependencies).getIpNeighborMonitor(any(), any(),
+                neighborCaptor.capture());
+
+        mIpServer = new IpServer(
+                IFACE_NAME, mLooper.getLooper(), interfaceType, mSharedLog, mNetd, mBpfCoordinator,
+                mCallback, usingLegacyDhcp, usingBpfOffload, mAddressCoordinator, mDependencies);
+        mIpServer.start();
+        mNeighborEventConsumer = neighborCaptor.getValue();
+
+        // Starting the state machine always puts us in a consistent state and notifies
+        // the rest of the world that we've changed from an unknown to available state.
+        mLooper.dispatchAll();
+        reset(mNetd, mCallback);
+
+        when(mRaDaemon.start()).thenReturn(true);
+    }
+
+    private void initTetheredStateMachine(int interfaceType, String upstreamIface)
+            throws Exception {
+        initTetheredStateMachine(interfaceType, upstreamIface, false,
+                DEFAULT_USING_BPF_OFFLOAD);
+    }
+
+    private void initTetheredStateMachine(int interfaceType, String upstreamIface,
+            boolean usingLegacyDhcp, boolean usingBpfOffload) throws Exception {
+        initStateMachine(interfaceType, usingLegacyDhcp, usingBpfOffload);
+        dispatchCommand(IpServer.CMD_TETHER_REQUESTED, STATE_TETHERED);
+        if (upstreamIface != null) {
+            LinkProperties lp = new LinkProperties();
+            lp.setInterfaceName(upstreamIface);
+            dispatchTetherConnectionChanged(upstreamIface, lp, 0);
+        }
+        reset(mNetd, mCallback, mAddressCoordinator);
+        when(mAddressCoordinator.requestDownstreamAddress(any(), anyBoolean())).thenReturn(
+                mTestAddress);
+    }
+
+    private void setUpDhcpServer() throws Exception {
+        doAnswer(inv -> {
+            final IDhcpServerCallbacks cb = inv.getArgument(2);
+            new Thread(() -> {
+                try {
+                    cb.onDhcpServerCreated(STATUS_SUCCESS, mDhcpServer);
+                } catch (RemoteException e) {
+                    fail(e.getMessage());
+                }
+            }).run();
+            return null;
+        }).when(mDependencies).makeDhcpServer(any(), mDhcpParamsCaptor.capture(), any());
+    }
+
+    @Before public void setUp() throws Exception {
+        MockitoAnnotations.initMocks(this);
+        when(mSharedLog.forSubComponent(anyString())).thenReturn(mSharedLog);
+        when(mAddressCoordinator.requestDownstreamAddress(any(), anyBoolean())).thenReturn(
+                mTestAddress);
+        when(mTetherConfig.isBpfOffloadEnabled()).thenReturn(true /* default value */);
+
+        mBpfCoordinator = spy(new BpfCoordinator(
+                new BpfCoordinator.Dependencies() {
+                    @NonNull
+                    public Handler getHandler() {
+                        return new Handler(mLooper.getLooper());
+                    }
+
+                    @NonNull
+                    public INetd getNetd() {
+                        return mNetd;
+                    }
+
+                    @NonNull
+                    public NetworkStatsManager getNetworkStatsManager() {
+                        return mStatsManager;
+                    }
+
+                    @NonNull
+                    public SharedLog getSharedLog() {
+                        return mSharedLog;
+                    }
+
+                    @Nullable
+                    public TetheringConfiguration getTetherConfig() {
+                        return mTetherConfig;
+                    }
+                }));
+
+        setUpDhcpServer();
+    }
+
+    @Test
+    public void startsOutAvailable() {
+        when(mDependencies.getIpNeighborMonitor(any(), any(), any()))
+                .thenReturn(mIpNeighborMonitor);
+        mIpServer = new IpServer(IFACE_NAME, mLooper.getLooper(), TETHERING_BLUETOOTH, mSharedLog,
+                mNetd, mBpfCoordinator, mCallback, false /* usingLegacyDhcp */,
+                DEFAULT_USING_BPF_OFFLOAD, mAddressCoordinator, mDependencies);
+        mIpServer.start();
+        mLooper.dispatchAll();
+        verify(mCallback).updateInterfaceState(
+                mIpServer, STATE_AVAILABLE, TETHER_ERROR_NO_ERROR);
+        verify(mCallback).updateLinkProperties(eq(mIpServer), any(LinkProperties.class));
+        verifyNoMoreInteractions(mCallback, mNetd);
+    }
+
+    @Test
+    public void shouldDoNothingUntilRequested() throws Exception {
+        initStateMachine(TETHERING_BLUETOOTH);
+        final int [] noOp_commands = {
+            IpServer.CMD_TETHER_UNREQUESTED,
+            IpServer.CMD_IP_FORWARDING_ENABLE_ERROR,
+            IpServer.CMD_IP_FORWARDING_DISABLE_ERROR,
+            IpServer.CMD_START_TETHERING_ERROR,
+            IpServer.CMD_STOP_TETHERING_ERROR,
+            IpServer.CMD_SET_DNS_FORWARDERS_ERROR,
+            IpServer.CMD_TETHER_CONNECTION_CHANGED
+        };
+        for (int command : noOp_commands) {
+            // None of these commands should trigger us to request action from
+            // the rest of the system.
+            dispatchCommand(command);
+            verifyNoMoreInteractions(mNetd, mCallback);
+        }
+    }
+
+    @Test
+    public void handlesImmediateInterfaceDown() throws Exception {
+        initStateMachine(TETHERING_BLUETOOTH);
+
+        dispatchCommand(IpServer.CMD_INTERFACE_DOWN);
+        verify(mCallback).updateInterfaceState(
+                mIpServer, STATE_UNAVAILABLE, TETHER_ERROR_NO_ERROR);
+        verify(mCallback).updateLinkProperties(eq(mIpServer), any(LinkProperties.class));
+        verifyNoMoreInteractions(mNetd, mCallback);
+    }
+
+    @Test
+    public void canBeTethered() throws Exception {
+        initStateMachine(TETHERING_BLUETOOTH);
+
+        dispatchCommand(IpServer.CMD_TETHER_REQUESTED, STATE_TETHERED);
+        InOrder inOrder = inOrder(mCallback, mNetd);
+        inOrder.verify(mNetd).tetherInterfaceAdd(IFACE_NAME);
+        inOrder.verify(mNetd).networkAddInterface(INetd.LOCAL_NET_ID, IFACE_NAME);
+        // One for ipv4 route, one for ipv6 link local route.
+        inOrder.verify(mNetd, times(2)).networkAddRoute(eq(INetd.LOCAL_NET_ID), eq(IFACE_NAME),
+                any(), any());
+        inOrder.verify(mCallback).updateInterfaceState(
+                mIpServer, STATE_TETHERED, TETHER_ERROR_NO_ERROR);
+        inOrder.verify(mCallback).updateLinkProperties(
+                eq(mIpServer), any(LinkProperties.class));
+        verifyNoMoreInteractions(mNetd, mCallback);
+    }
+
+    @Test
+    public void canUnrequestTethering() throws Exception {
+        initTetheredStateMachine(TETHERING_BLUETOOTH, null);
+
+        dispatchCommand(IpServer.CMD_TETHER_UNREQUESTED);
+        InOrder inOrder = inOrder(mCallback, mNetd, mAddressCoordinator);
+        inOrder.verify(mNetd).tetherApplyDnsInterfaces();
+        inOrder.verify(mNetd).tetherInterfaceRemove(IFACE_NAME);
+        inOrder.verify(mNetd).networkRemoveInterface(INetd.LOCAL_NET_ID, IFACE_NAME);
+        inOrder.verify(mNetd).interfaceSetCfg(argThat(cfg -> IFACE_NAME.equals(cfg.ifName)));
+        inOrder.verify(mAddressCoordinator).releaseDownstream(any());
+        inOrder.verify(mCallback).updateInterfaceState(
+                mIpServer, STATE_AVAILABLE, TETHER_ERROR_NO_ERROR);
+        inOrder.verify(mCallback).updateLinkProperties(
+                eq(mIpServer), any(LinkProperties.class));
+        verifyNoMoreInteractions(mNetd, mCallback, mAddressCoordinator);
+    }
+
+    @Test
+    public void canBeTetheredAsUsb() throws Exception {
+        initStateMachine(TETHERING_USB);
+
+        dispatchCommand(IpServer.CMD_TETHER_REQUESTED, STATE_TETHERED);
+        InOrder inOrder = inOrder(mCallback, mNetd, mAddressCoordinator);
+        inOrder.verify(mAddressCoordinator).requestDownstreamAddress(any(), eq(true));
+        inOrder.verify(mNetd).interfaceSetCfg(argThat(cfg ->
+                  IFACE_NAME.equals(cfg.ifName) && assertContainsFlag(cfg.flags, IF_STATE_UP)));
+        inOrder.verify(mNetd).tetherInterfaceAdd(IFACE_NAME);
+        inOrder.verify(mNetd).networkAddInterface(INetd.LOCAL_NET_ID, IFACE_NAME);
+        inOrder.verify(mNetd, times(2)).networkAddRoute(eq(INetd.LOCAL_NET_ID), eq(IFACE_NAME),
+                any(), any());
+        inOrder.verify(mCallback).updateInterfaceState(
+                mIpServer, STATE_TETHERED, TETHER_ERROR_NO_ERROR);
+        inOrder.verify(mCallback).updateLinkProperties(
+                eq(mIpServer), mLinkPropertiesCaptor.capture());
+        assertIPv4AddressAndDirectlyConnectedRoute(mLinkPropertiesCaptor.getValue());
+        verifyNoMoreInteractions(mNetd, mCallback, mAddressCoordinator);
+    }
+
+    @Test
+    public void canBeTetheredAsWifiP2p() throws Exception {
+        initStateMachine(TETHERING_WIFI_P2P);
+
+        dispatchCommand(IpServer.CMD_TETHER_REQUESTED, STATE_LOCAL_ONLY);
+        InOrder inOrder = inOrder(mCallback, mNetd, mAddressCoordinator);
+        inOrder.verify(mAddressCoordinator).requestDownstreamAddress(any(), eq(true));
+        inOrder.verify(mNetd).interfaceSetCfg(argThat(cfg ->
+                  IFACE_NAME.equals(cfg.ifName) && assertNotContainsFlag(cfg.flags, IF_STATE_UP)));
+        inOrder.verify(mNetd).tetherInterfaceAdd(IFACE_NAME);
+        inOrder.verify(mNetd).networkAddInterface(INetd.LOCAL_NET_ID, IFACE_NAME);
+        inOrder.verify(mNetd, times(2)).networkAddRoute(eq(INetd.LOCAL_NET_ID), eq(IFACE_NAME),
+                any(), any());
+        inOrder.verify(mCallback).updateInterfaceState(
+                mIpServer, STATE_LOCAL_ONLY, TETHER_ERROR_NO_ERROR);
+        inOrder.verify(mCallback).updateLinkProperties(
+                eq(mIpServer), mLinkPropertiesCaptor.capture());
+        assertIPv4AddressAndDirectlyConnectedRoute(mLinkPropertiesCaptor.getValue());
+        verifyNoMoreInteractions(mNetd, mCallback, mAddressCoordinator);
+    }
+
+    @Test
+    public void handlesFirstUpstreamChange() throws Exception {
+        initTetheredStateMachine(TETHERING_BLUETOOTH, null);
+
+        // Telling the state machine about its upstream interface triggers
+        // a little more configuration.
+        dispatchTetherConnectionChanged(UPSTREAM_IFACE);
+        InOrder inOrder = inOrder(mNetd);
+        inOrder.verify(mNetd).tetherAddForward(IFACE_NAME, UPSTREAM_IFACE);
+        inOrder.verify(mNetd).ipfwdAddInterfaceForward(IFACE_NAME, UPSTREAM_IFACE);
+        verifyNoMoreInteractions(mNetd, mCallback);
+    }
+
+    @Test
+    public void handlesChangingUpstream() throws Exception {
+        initTetheredStateMachine(TETHERING_BLUETOOTH, UPSTREAM_IFACE);
+
+        dispatchTetherConnectionChanged(UPSTREAM_IFACE2);
+        InOrder inOrder = inOrder(mNetd);
+        inOrder.verify(mNetd).ipfwdRemoveInterfaceForward(IFACE_NAME, UPSTREAM_IFACE);
+        inOrder.verify(mNetd).tetherRemoveForward(IFACE_NAME, UPSTREAM_IFACE);
+        inOrder.verify(mNetd).tetherAddForward(IFACE_NAME, UPSTREAM_IFACE2);
+        inOrder.verify(mNetd).ipfwdAddInterfaceForward(IFACE_NAME, UPSTREAM_IFACE2);
+        verifyNoMoreInteractions(mNetd, mCallback);
+    }
+
+    @Test
+    public void handlesChangingUpstreamNatFailure() throws Exception {
+        initTetheredStateMachine(TETHERING_WIFI, UPSTREAM_IFACE);
+
+        doThrow(RemoteException.class).when(mNetd).tetherAddForward(IFACE_NAME, UPSTREAM_IFACE2);
+
+        dispatchTetherConnectionChanged(UPSTREAM_IFACE2);
+        InOrder inOrder = inOrder(mNetd);
+        inOrder.verify(mNetd).ipfwdRemoveInterfaceForward(IFACE_NAME, UPSTREAM_IFACE);
+        inOrder.verify(mNetd).tetherRemoveForward(IFACE_NAME, UPSTREAM_IFACE);
+        inOrder.verify(mNetd).tetherAddForward(IFACE_NAME, UPSTREAM_IFACE2);
+        inOrder.verify(mNetd).ipfwdRemoveInterfaceForward(IFACE_NAME, UPSTREAM_IFACE2);
+        inOrder.verify(mNetd).tetherRemoveForward(IFACE_NAME, UPSTREAM_IFACE2);
+    }
+
+    @Test
+    public void handlesChangingUpstreamInterfaceForwardingFailure() throws Exception {
+        initTetheredStateMachine(TETHERING_WIFI, UPSTREAM_IFACE);
+
+        doThrow(RemoteException.class).when(mNetd).ipfwdAddInterfaceForward(
+                IFACE_NAME, UPSTREAM_IFACE2);
+
+        dispatchTetherConnectionChanged(UPSTREAM_IFACE2);
+        InOrder inOrder = inOrder(mNetd);
+        inOrder.verify(mNetd).ipfwdRemoveInterfaceForward(IFACE_NAME, UPSTREAM_IFACE);
+        inOrder.verify(mNetd).tetherRemoveForward(IFACE_NAME, UPSTREAM_IFACE);
+        inOrder.verify(mNetd).tetherAddForward(IFACE_NAME, UPSTREAM_IFACE2);
+        inOrder.verify(mNetd).ipfwdAddInterfaceForward(IFACE_NAME, UPSTREAM_IFACE2);
+        inOrder.verify(mNetd).ipfwdRemoveInterfaceForward(IFACE_NAME, UPSTREAM_IFACE2);
+        inOrder.verify(mNetd).tetherRemoveForward(IFACE_NAME, UPSTREAM_IFACE2);
+    }
+
+    @Test
+    public void canUnrequestTetheringWithUpstream() throws Exception {
+        initTetheredStateMachine(TETHERING_BLUETOOTH, UPSTREAM_IFACE);
+
+        dispatchCommand(IpServer.CMD_TETHER_UNREQUESTED);
+        InOrder inOrder = inOrder(mNetd, mCallback, mAddressCoordinator);
+        inOrder.verify(mNetd).ipfwdRemoveInterfaceForward(IFACE_NAME, UPSTREAM_IFACE);
+        inOrder.verify(mNetd).tetherRemoveForward(IFACE_NAME, UPSTREAM_IFACE);
+        inOrder.verify(mNetd).tetherApplyDnsInterfaces();
+        inOrder.verify(mNetd).tetherInterfaceRemove(IFACE_NAME);
+        inOrder.verify(mNetd).networkRemoveInterface(INetd.LOCAL_NET_ID, IFACE_NAME);
+        inOrder.verify(mNetd).interfaceSetCfg(argThat(cfg -> IFACE_NAME.equals(cfg.ifName)));
+        inOrder.verify(mAddressCoordinator).releaseDownstream(any());
+        inOrder.verify(mCallback).updateInterfaceState(
+                mIpServer, STATE_AVAILABLE, TETHER_ERROR_NO_ERROR);
+        inOrder.verify(mCallback).updateLinkProperties(
+                eq(mIpServer), any(LinkProperties.class));
+        verifyNoMoreInteractions(mNetd, mCallback, mAddressCoordinator);
+    }
+
+    @Test
+    public void interfaceDownLeadsToUnavailable() throws Exception {
+        for (boolean shouldThrow : new boolean[]{true, false}) {
+            initTetheredStateMachine(TETHERING_USB, null);
+
+            if (shouldThrow) {
+                doThrow(RemoteException.class).when(mNetd).tetherInterfaceRemove(IFACE_NAME);
+            }
+            dispatchCommand(IpServer.CMD_INTERFACE_DOWN);
+            InOrder usbTeardownOrder = inOrder(mNetd, mCallback);
+            // Currently IpServer interfaceSetCfg twice to stop IPv4. One just set interface down
+            // Another one is set IPv4 to 0.0.0.0/0 as clearng ipv4 address.
+            usbTeardownOrder.verify(mNetd, times(2)).interfaceSetCfg(
+                    argThat(cfg -> IFACE_NAME.equals(cfg.ifName)));
+            usbTeardownOrder.verify(mCallback).updateInterfaceState(
+                    mIpServer, STATE_UNAVAILABLE, TETHER_ERROR_NO_ERROR);
+            usbTeardownOrder.verify(mCallback).updateLinkProperties(
+                    eq(mIpServer), mLinkPropertiesCaptor.capture());
+            assertNoAddressesNorRoutes(mLinkPropertiesCaptor.getValue());
+        }
+    }
+
+    @Test
+    public void usbShouldBeTornDownOnTetherError() throws Exception {
+        initStateMachine(TETHERING_USB);
+
+        doThrow(RemoteException.class).when(mNetd).tetherInterfaceAdd(IFACE_NAME);
+        dispatchCommand(IpServer.CMD_TETHER_REQUESTED, STATE_TETHERED);
+        InOrder usbTeardownOrder = inOrder(mNetd, mCallback);
+        usbTeardownOrder.verify(mNetd).interfaceSetCfg(
+                argThat(cfg -> IFACE_NAME.equals(cfg.ifName)));
+        usbTeardownOrder.verify(mNetd).tetherInterfaceAdd(IFACE_NAME);
+
+        usbTeardownOrder.verify(mNetd, times(2)).interfaceSetCfg(
+                argThat(cfg -> IFACE_NAME.equals(cfg.ifName)));
+        usbTeardownOrder.verify(mCallback).updateInterfaceState(
+                mIpServer, STATE_AVAILABLE, TETHER_ERROR_TETHER_IFACE_ERROR);
+        usbTeardownOrder.verify(mCallback).updateLinkProperties(
+                eq(mIpServer), mLinkPropertiesCaptor.capture());
+        assertNoAddressesNorRoutes(mLinkPropertiesCaptor.getValue());
+    }
+
+    @Test
+    public void shouldTearDownUsbOnUpstreamError() throws Exception {
+        initTetheredStateMachine(TETHERING_USB, null);
+
+        doThrow(RemoteException.class).when(mNetd).tetherAddForward(anyString(), anyString());
+        dispatchTetherConnectionChanged(UPSTREAM_IFACE);
+        InOrder usbTeardownOrder = inOrder(mNetd, mCallback);
+        usbTeardownOrder.verify(mNetd).tetherAddForward(IFACE_NAME, UPSTREAM_IFACE);
+
+        usbTeardownOrder.verify(mNetd, times(2)).interfaceSetCfg(
+                argThat(cfg -> IFACE_NAME.equals(cfg.ifName)));
+        usbTeardownOrder.verify(mCallback).updateInterfaceState(
+                mIpServer, STATE_AVAILABLE, TETHER_ERROR_ENABLE_FORWARDING_ERROR);
+        usbTeardownOrder.verify(mCallback).updateLinkProperties(
+                eq(mIpServer), mLinkPropertiesCaptor.capture());
+        assertNoAddressesNorRoutes(mLinkPropertiesCaptor.getValue());
+    }
+
+    @Test
+    public void ignoresDuplicateUpstreamNotifications() throws Exception {
+        initTetheredStateMachine(TETHERING_WIFI, UPSTREAM_IFACE);
+
+        verifyNoMoreInteractions(mNetd, mCallback);
+
+        for (int i = 0; i < 5; i++) {
+            dispatchTetherConnectionChanged(UPSTREAM_IFACE);
+            verifyNoMoreInteractions(mNetd, mCallback);
+        }
+    }
+
+    @Test
+    public void startsDhcpServer() throws Exception {
+        initTetheredStateMachine(TETHERING_WIFI, UPSTREAM_IFACE);
+        dispatchTetherConnectionChanged(UPSTREAM_IFACE);
+
+        assertDhcpStarted(PrefixUtils.asIpPrefix(mTestAddress));
+    }
+
+    @Test
+    public void startsDhcpServerOnBluetooth() throws Exception {
+        initTetheredStateMachine(TETHERING_BLUETOOTH, UPSTREAM_IFACE);
+        dispatchTetherConnectionChanged(UPSTREAM_IFACE);
+
+        assertDhcpStarted(mBluetoothPrefix);
+    }
+
+    @Test
+    public void startsDhcpServerOnWifiP2p() throws Exception {
+        initTetheredStateMachine(TETHERING_WIFI_P2P, UPSTREAM_IFACE);
+        dispatchTetherConnectionChanged(UPSTREAM_IFACE);
+
+        assertDhcpStarted(PrefixUtils.asIpPrefix(mTestAddress));
+    }
+
+    @Test
+    public void startsDhcpServerOnNcm() throws Exception {
+        initStateMachine(TETHERING_NCM);
+        dispatchCommand(IpServer.CMD_TETHER_REQUESTED, STATE_LOCAL_ONLY);
+        dispatchTetherConnectionChanged(UPSTREAM_IFACE);
+
+        assertDhcpStarted(new IpPrefix("192.168.42.0/24"));
+    }
+
+    @Test
+    public void testOnNewPrefixRequest() throws Exception {
+        initStateMachine(TETHERING_NCM);
+        dispatchCommand(IpServer.CMD_TETHER_REQUESTED, STATE_LOCAL_ONLY);
+
+        final IDhcpEventCallbacks eventCallbacks;
+        final ArgumentCaptor<IDhcpEventCallbacks> dhcpEventCbsCaptor =
+                 ArgumentCaptor.forClass(IDhcpEventCallbacks.class);
+        verify(mDhcpServer, timeout(MAKE_DHCPSERVER_TIMEOUT_MS).times(1)).startWithCallbacks(
+                any(), dhcpEventCbsCaptor.capture());
+        eventCallbacks = dhcpEventCbsCaptor.getValue();
+        assertDhcpStarted(new IpPrefix("192.168.42.0/24"));
+
+        final ArgumentCaptor<LinkProperties> lpCaptor =
+                ArgumentCaptor.forClass(LinkProperties.class);
+        InOrder inOrder = inOrder(mNetd, mCallback, mAddressCoordinator);
+        inOrder.verify(mAddressCoordinator).requestDownstreamAddress(any(), eq(true));
+        inOrder.verify(mNetd).networkAddInterface(INetd.LOCAL_NET_ID, IFACE_NAME);
+        // One for ipv4 route, one for ipv6 link local route.
+        inOrder.verify(mNetd, times(2)).networkAddRoute(eq(INetd.LOCAL_NET_ID), eq(IFACE_NAME),
+                any(), any());
+        inOrder.verify(mCallback).updateInterfaceState(
+                mIpServer, STATE_LOCAL_ONLY, TETHER_ERROR_NO_ERROR);
+        inOrder.verify(mCallback).updateLinkProperties(eq(mIpServer), lpCaptor.capture());
+        verifyNoMoreInteractions(mCallback, mAddressCoordinator);
+
+        // Simulate the DHCP server receives DHCPDECLINE on MirrorLink and then signals
+        // onNewPrefixRequest callback.
+        final LinkAddress newAddress = new LinkAddress("192.168.100.125/24");
+        when(mAddressCoordinator.requestDownstreamAddress(any(), anyBoolean())).thenReturn(
+                newAddress);
+        eventCallbacks.onNewPrefixRequest(new IpPrefix("192.168.42.0/24"));
+        mLooper.dispatchAll();
+
+        inOrder.verify(mAddressCoordinator).requestDownstreamAddress(any(), eq(false));
+        inOrder.verify(mNetd).tetherApplyDnsInterfaces();
+        inOrder.verify(mCallback).updateLinkProperties(eq(mIpServer), lpCaptor.capture());
+        verifyNoMoreInteractions(mCallback);
+
+        final LinkProperties linkProperties = lpCaptor.getValue();
+        final List<LinkAddress> linkAddresses = linkProperties.getLinkAddresses();
+        assertEquals(1, linkProperties.getLinkAddresses().size());
+        assertEquals(1, linkProperties.getRoutes().size());
+        final IpPrefix prefix = new IpPrefix(linkAddresses.get(0).getAddress(),
+                linkAddresses.get(0).getPrefixLength());
+        assertNotEquals(prefix, new IpPrefix("192.168.42.0/24"));
+
+        verify(mDhcpServer).updateParams(mDhcpParamsCaptor.capture(), any());
+        assertDhcpServingParams(mDhcpParamsCaptor.getValue(), prefix);
+    }
+
+    @Test
+    public void doesNotStartDhcpServerIfDisabled() throws Exception {
+        initTetheredStateMachine(TETHERING_WIFI, UPSTREAM_IFACE, true /* usingLegacyDhcp */,
+                DEFAULT_USING_BPF_OFFLOAD);
+        dispatchTetherConnectionChanged(UPSTREAM_IFACE);
+
+        verify(mDependencies, never()).makeDhcpServer(any(), any(), any());
+    }
+
+    private InetAddress addr(String addr) throws Exception {
+        return InetAddresses.parseNumericAddress(addr);
+    }
+
+    private void recvNewNeigh(int ifindex, InetAddress addr, short nudState, MacAddress mac) {
+        mNeighborEventConsumer.accept(new NeighborEvent(0, RTM_NEWNEIGH, ifindex, addr,
+                nudState, mac));
+        mLooper.dispatchAll();
+    }
+
+    private void recvDelNeigh(int ifindex, InetAddress addr, short nudState, MacAddress mac) {
+        mNeighborEventConsumer.accept(new NeighborEvent(0, RTM_DELNEIGH, ifindex, addr,
+                nudState, mac));
+        mLooper.dispatchAll();
+    }
+
+    /**
+     * Custom ArgumentMatcher for TetherOffloadRuleParcel. This is needed because generated stable
+     * AIDL classes don't have equals(), so we cannot just use eq(). A custom assert, such as:
+     *
+     * private void checkFooCalled(StableParcelable p, ...) {
+     *     ArgumentCaptor<FooParam> captor = ArgumentCaptor.forClass(FooParam.class);
+     *     verify(mMock).foo(captor.capture());
+     *     Foo foo = captor.getValue();
+     *     assertFooMatchesExpectations(foo);
+     * }
+     *
+     * almost works, but not quite. This is because if the code under test calls foo() twice, the
+     * first call to checkFooCalled() matches both the calls, putting both calls into the captor,
+     * and then fails with TooManyActualInvocations. It also makes it harder to use other mockito
+     * features such as never(), inOrder(), etc.
+     *
+     * This approach isn't great because if the match fails, the error message is unhelpful
+     * (actual: "android.net.TetherOffloadRuleParcel@8c827b0" or some such), but at least it does
+     * work.
+     *
+     * TODO: consider making the error message more readable by adding a method that catching the
+     * AssertionFailedError and throwing a new assertion with more details. See
+     * NetworkMonitorTest#verifyNetworkTested.
+     *
+     * See ConnectivityServiceTest#assertRoutesAdded for an alternative approach which solves the
+     * TooManyActualInvocations problem described above by forcing the caller of the custom assert
+     * method to specify all expected invocations in one call. This is useful when the stable
+     * parcelable class being asserted on has a corresponding Java object (eg., RouteInfo and
+     * RouteInfoParcelable), and the caller can just pass in a list of them. It not useful here
+     * because there is no such object.
+     */
+    private static class TetherOffloadRuleParcelMatcher implements
+            ArgumentMatcher<TetherOffloadRuleParcel> {
+        public final int upstreamIfindex;
+        public final InetAddress dst;
+        public final MacAddress dstMac;
+
+        TetherOffloadRuleParcelMatcher(int upstreamIfindex, InetAddress dst, MacAddress dstMac) {
+            this.upstreamIfindex = upstreamIfindex;
+            this.dst = dst;
+            this.dstMac = dstMac;
+        }
+
+        public boolean matches(TetherOffloadRuleParcel parcel) {
+            return upstreamIfindex == parcel.inputInterfaceIndex
+                    && (TEST_IFACE_PARAMS.index == parcel.outputInterfaceIndex)
+                    && Arrays.equals(dst.getAddress(), parcel.destination)
+                    && (128 == parcel.prefixLength)
+                    && Arrays.equals(TEST_IFACE_PARAMS.macAddr.toByteArray(), parcel.srcL2Address)
+                    && Arrays.equals(dstMac.toByteArray(), parcel.dstL2Address);
+        }
+
+        public String toString() {
+            return String.format("TetherOffloadRuleParcelMatcher(%d, %s, %s",
+                    upstreamIfindex, dst.getHostAddress(), dstMac);
+        }
+    }
+
+    @NonNull
+    private static TetherOffloadRuleParcel matches(
+            int upstreamIfindex, InetAddress dst, MacAddress dstMac) {
+        return argThat(new TetherOffloadRuleParcelMatcher(upstreamIfindex, dst, dstMac));
+    }
+
+    @NonNull
+    private static Ipv6ForwardingRule makeForwardingRule(
+            int upstreamIfindex, @NonNull InetAddress dst, @NonNull MacAddress dstMac) {
+        return new Ipv6ForwardingRule(upstreamIfindex, TEST_IFACE_PARAMS.index,
+                (Inet6Address) dst, TEST_IFACE_PARAMS.macAddr, dstMac);
+    }
+
+    @NonNull
+    private static TetherStatsParcel buildEmptyTetherStatsParcel(int ifIndex) {
+        TetherStatsParcel parcel = new TetherStatsParcel();
+        parcel.ifIndex = ifIndex;
+        return parcel;
+    }
+
+    private void resetNetdAndBpfCoordinator() throws Exception {
+        reset(mNetd, mBpfCoordinator);
+        when(mNetd.tetherOffloadGetStats()).thenReturn(new TetherStatsParcel[0]);
+        when(mNetd.tetherOffloadGetAndClearStats(UPSTREAM_IFINDEX))
+                .thenReturn(buildEmptyTetherStatsParcel(UPSTREAM_IFINDEX));
+        when(mNetd.tetherOffloadGetAndClearStats(UPSTREAM_IFINDEX2))
+                .thenReturn(buildEmptyTetherStatsParcel(UPSTREAM_IFINDEX2));
+    }
+
+    @Test
+    public void addRemoveipv6ForwardingRules() throws Exception {
+        initTetheredStateMachine(TETHERING_WIFI, UPSTREAM_IFACE, false /* usingLegacyDhcp */,
+                DEFAULT_USING_BPF_OFFLOAD);
+
+        final int myIfindex = TEST_IFACE_PARAMS.index;
+        final int notMyIfindex = myIfindex - 1;
+
+        final MacAddress myMac = TEST_IFACE_PARAMS.macAddr;
+        final InetAddress neighA = InetAddresses.parseNumericAddress("2001:db8::1");
+        final InetAddress neighB = InetAddresses.parseNumericAddress("2001:db8::2");
+        final InetAddress neighLL = InetAddresses.parseNumericAddress("fe80::1");
+        final InetAddress neighMC = InetAddresses.parseNumericAddress("ff02::1234");
+        final MacAddress macNull = MacAddress.fromString("00:00:00:00:00:00");
+        final MacAddress macA = MacAddress.fromString("00:00:00:00:00:0a");
+        final MacAddress macB = MacAddress.fromString("11:22:33:00:00:0b");
+
+        resetNetdAndBpfCoordinator();
+        verifyNoMoreInteractions(mBpfCoordinator, mNetd);
+
+        // TODO: Perhaps verify the interaction of tetherOffloadSetInterfaceQuota and
+        // tetherOffloadGetAndClearStats in netd while the rules are changed.
+
+        // Events on other interfaces are ignored.
+        recvNewNeigh(notMyIfindex, neighA, NUD_REACHABLE, macA);
+        verifyNoMoreInteractions(mBpfCoordinator, mNetd);
+
+        // Events on this interface are received and sent to netd.
+        recvNewNeigh(myIfindex, neighA, NUD_REACHABLE, macA);
+        verify(mBpfCoordinator).tetherOffloadRuleAdd(
+                mIpServer, makeForwardingRule(UPSTREAM_IFINDEX, neighA, macA));
+        verify(mNetd).tetherOffloadRuleAdd(matches(UPSTREAM_IFINDEX, neighA, macA));
+        resetNetdAndBpfCoordinator();
+
+        recvNewNeigh(myIfindex, neighB, NUD_REACHABLE, macB);
+        verify(mBpfCoordinator).tetherOffloadRuleAdd(
+                mIpServer, makeForwardingRule(UPSTREAM_IFINDEX, neighB, macB));
+        verify(mNetd).tetherOffloadRuleAdd(matches(UPSTREAM_IFINDEX, neighB, macB));
+        resetNetdAndBpfCoordinator();
+
+        // Link-local and multicast neighbors are ignored.
+        recvNewNeigh(myIfindex, neighLL, NUD_REACHABLE, macA);
+        verifyNoMoreInteractions(mBpfCoordinator, mNetd);
+        recvNewNeigh(myIfindex, neighMC, NUD_REACHABLE, macA);
+        verifyNoMoreInteractions(mBpfCoordinator, mNetd);
+
+        // A neighbor that is no longer valid causes the rule to be removed.
+        // NUD_FAILED events do not have a MAC address.
+        recvNewNeigh(myIfindex, neighA, NUD_FAILED, null);
+        verify(mBpfCoordinator).tetherOffloadRuleRemove(
+                mIpServer, makeForwardingRule(UPSTREAM_IFINDEX, neighA, macNull));
+        verify(mNetd).tetherOffloadRuleRemove(matches(UPSTREAM_IFINDEX, neighA, macNull));
+        resetNetdAndBpfCoordinator();
+
+        // A neighbor that is deleted causes the rule to be removed.
+        recvDelNeigh(myIfindex, neighB, NUD_STALE, macB);
+        verify(mBpfCoordinator).tetherOffloadRuleRemove(
+                mIpServer,  makeForwardingRule(UPSTREAM_IFINDEX, neighB, macNull));
+        verify(mNetd).tetherOffloadRuleRemove(matches(UPSTREAM_IFINDEX, neighB, macNull));
+        resetNetdAndBpfCoordinator();
+
+        // Upstream changes result in updating the rules.
+        recvNewNeigh(myIfindex, neighA, NUD_REACHABLE, macA);
+        recvNewNeigh(myIfindex, neighB, NUD_REACHABLE, macB);
+        resetNetdAndBpfCoordinator();
+
+        InOrder inOrder = inOrder(mNetd);
+        LinkProperties lp = new LinkProperties();
+        lp.setInterfaceName(UPSTREAM_IFACE2);
+        dispatchTetherConnectionChanged(UPSTREAM_IFACE2, lp, -1);
+        verify(mBpfCoordinator).tetherOffloadRuleUpdate(mIpServer, UPSTREAM_IFINDEX2);
+        inOrder.verify(mNetd).tetherOffloadRuleRemove(matches(UPSTREAM_IFINDEX, neighA, macA));
+        inOrder.verify(mNetd).tetherOffloadRuleAdd(matches(UPSTREAM_IFINDEX2, neighA, macA));
+        inOrder.verify(mNetd).tetherOffloadRuleRemove(matches(UPSTREAM_IFINDEX, neighB, macB));
+        inOrder.verify(mNetd).tetherOffloadRuleAdd(matches(UPSTREAM_IFINDEX2, neighB, macB));
+        resetNetdAndBpfCoordinator();
+
+        // When the upstream is lost, rules are removed.
+        dispatchTetherConnectionChanged(null, null, 0);
+        // Clear function is called two times by:
+        // - processMessage CMD_TETHER_CONNECTION_CHANGED for the upstream is lost.
+        // - processMessage CMD_IPV6_TETHER_UPDATE for the IPv6 upstream is lost.
+        // See dispatchTetherConnectionChanged.
+        verify(mBpfCoordinator, times(2)).tetherOffloadRuleClear(mIpServer);
+        verify(mNetd).tetherOffloadRuleRemove(matches(UPSTREAM_IFINDEX2, neighA, macA));
+        verify(mNetd).tetherOffloadRuleRemove(matches(UPSTREAM_IFINDEX2, neighB, macB));
+        resetNetdAndBpfCoordinator();
+
+        // If the upstream is IPv4-only, no rules are added.
+        dispatchTetherConnectionChanged(UPSTREAM_IFACE);
+        resetNetdAndBpfCoordinator();
+        recvNewNeigh(myIfindex, neighA, NUD_REACHABLE, macA);
+        // Clear function is called by #updateIpv6ForwardingRules for the IPv6 upstream is lost.
+        verify(mBpfCoordinator).tetherOffloadRuleClear(mIpServer);
+        verifyNoMoreInteractions(mBpfCoordinator, mNetd);
+
+        // Rules can be added again once upstream IPv6 connectivity is available.
+        lp.setInterfaceName(UPSTREAM_IFACE);
+        dispatchTetherConnectionChanged(UPSTREAM_IFACE, lp, -1);
+        recvNewNeigh(myIfindex, neighB, NUD_REACHABLE, macB);
+        verify(mBpfCoordinator).tetherOffloadRuleAdd(
+                mIpServer, makeForwardingRule(UPSTREAM_IFINDEX, neighB, macB));
+        verify(mNetd).tetherOffloadRuleAdd(matches(UPSTREAM_IFINDEX, neighB, macB));
+        verify(mBpfCoordinator, never()).tetherOffloadRuleAdd(
+                mIpServer, makeForwardingRule(UPSTREAM_IFINDEX, neighA, macA));
+        verify(mNetd, never()).tetherOffloadRuleAdd(matches(UPSTREAM_IFINDEX, neighA, macA));
+
+        // If upstream IPv6 connectivity is lost, rules are removed.
+        resetNetdAndBpfCoordinator();
+        dispatchTetherConnectionChanged(UPSTREAM_IFACE, null, 0);
+        verify(mBpfCoordinator).tetherOffloadRuleClear(mIpServer);
+        verify(mNetd).tetherOffloadRuleRemove(matches(UPSTREAM_IFINDEX, neighB, macB));
+
+        // When the interface goes down, rules are removed.
+        lp.setInterfaceName(UPSTREAM_IFACE);
+        dispatchTetherConnectionChanged(UPSTREAM_IFACE, lp, -1);
+        recvNewNeigh(myIfindex, neighA, NUD_REACHABLE, macA);
+        recvNewNeigh(myIfindex, neighB, NUD_REACHABLE, macB);
+        verify(mBpfCoordinator).tetherOffloadRuleAdd(
+                mIpServer, makeForwardingRule(UPSTREAM_IFINDEX, neighA, macA));
+        verify(mNetd).tetherOffloadRuleAdd(matches(UPSTREAM_IFINDEX, neighA, macA));
+        verify(mBpfCoordinator).tetherOffloadRuleAdd(
+                mIpServer, makeForwardingRule(UPSTREAM_IFINDEX, neighB, macB));
+        verify(mNetd).tetherOffloadRuleAdd(matches(UPSTREAM_IFINDEX, neighB, macB));
+        resetNetdAndBpfCoordinator();
+
+        mIpServer.stop();
+        mLooper.dispatchAll();
+        verify(mBpfCoordinator).tetherOffloadRuleClear(mIpServer);
+        verify(mNetd).tetherOffloadRuleRemove(matches(UPSTREAM_IFINDEX, neighA, macA));
+        verify(mNetd).tetherOffloadRuleRemove(matches(UPSTREAM_IFINDEX, neighB, macB));
+        verify(mIpNeighborMonitor).stop();
+        resetNetdAndBpfCoordinator();
+    }
+
+    @Test
+    public void enableDisableUsingBpfOffload() throws Exception {
+        final int myIfindex = TEST_IFACE_PARAMS.index;
+        final InetAddress neigh = InetAddresses.parseNumericAddress("2001:db8::1");
+        final MacAddress macA = MacAddress.fromString("00:00:00:00:00:0a");
+        final MacAddress macNull = MacAddress.fromString("00:00:00:00:00:00");
+
+        // Expect that rules can be only added/removed when the BPF offload config is enabled.
+        // Note that the BPF offload disabled case is not a realistic test case. Because IP
+        // neighbor monitor doesn't start if BPF offload is disabled, there should have no
+        // neighbor event listening. This is used for testing the protection check just in case.
+        // TODO: Perhaps remove the BPF offload disabled case test once this check isn't needed
+        // anymore.
+
+        // [1] Enable BPF offload.
+        // A neighbor that is added or deleted causes the rule to be added or removed.
+        initTetheredStateMachine(TETHERING_WIFI, UPSTREAM_IFACE, false /* usingLegacyDhcp */,
+                true /* usingBpfOffload */);
+        resetNetdAndBpfCoordinator();
+
+        recvNewNeigh(myIfindex, neigh, NUD_REACHABLE, macA);
+        verify(mBpfCoordinator).tetherOffloadRuleAdd(
+                mIpServer, makeForwardingRule(UPSTREAM_IFINDEX, neigh, macA));
+        verify(mNetd).tetherOffloadRuleAdd(matches(UPSTREAM_IFINDEX, neigh, macA));
+        resetNetdAndBpfCoordinator();
+
+        recvDelNeigh(myIfindex, neigh, NUD_STALE, macA);
+        verify(mBpfCoordinator).tetherOffloadRuleRemove(
+                mIpServer, makeForwardingRule(UPSTREAM_IFINDEX, neigh, macNull));
+        verify(mNetd).tetherOffloadRuleRemove(matches(UPSTREAM_IFINDEX, neigh, macNull));
+        resetNetdAndBpfCoordinator();
+
+        // [2] Disable BPF offload.
+        // A neighbor that is added or deleted doesn’t cause the rule to be added or removed.
+        initTetheredStateMachine(TETHERING_WIFI, UPSTREAM_IFACE, false /* usingLegacyDhcp */,
+                false /* usingBpfOffload */);
+        resetNetdAndBpfCoordinator();
+
+        recvNewNeigh(myIfindex, neigh, NUD_REACHABLE, macA);
+        verify(mBpfCoordinator, never()).tetherOffloadRuleAdd(any(), any());
+        verify(mNetd, never()).tetherOffloadRuleAdd(any());
+        resetNetdAndBpfCoordinator();
+
+        recvDelNeigh(myIfindex, neigh, NUD_STALE, macA);
+        verify(mBpfCoordinator, never()).tetherOffloadRuleRemove(any(), any());
+        verify(mNetd, never()).tetherOffloadRuleRemove(any());
+        resetNetdAndBpfCoordinator();
+    }
+
+    @Test
+    public void doesNotStartIpNeighborMonitorIfBpfOffloadDisabled() throws Exception {
+        initTetheredStateMachine(TETHERING_WIFI, UPSTREAM_IFACE, false /* usingLegacyDhcp */,
+                false /* usingBpfOffload */);
+
+        // IP neighbor monitor doesn't start if BPF offload is disabled.
+        verify(mIpNeighborMonitor, never()).start();
+    }
+
+    private LinkProperties buildIpv6OnlyLinkProperties(final String iface) {
+        final LinkProperties linkProp = new LinkProperties();
+        linkProp.setInterfaceName(iface);
+        linkProp.addLinkAddress(new LinkAddress("2001:db8::1/64"));
+        linkProp.addRoute(new RouteInfo(new IpPrefix("::/0"), null, iface, RTN_UNICAST));
+        final InetAddress dns = InetAddresses.parseNumericAddress("2001:4860:4860::8888");
+        linkProp.addDnsServer(dns);
+
+        return linkProp;
+    }
+
+    @Test
+    public void testAdjustTtlValue() throws Exception {
+        final ArgumentCaptor<RaParams> raParamsCaptor =
+                ArgumentCaptor.forClass(RaParams.class);
+        initTetheredStateMachine(TETHERING_WIFI, UPSTREAM_IFACE);
+        verify(mRaDaemon).buildNewRa(any(), raParamsCaptor.capture());
+        final RaParams noV6Params = raParamsCaptor.getValue();
+        assertEquals(65, noV6Params.hopLimit);
+        reset(mRaDaemon);
+
+        when(mNetd.getProcSysNet(
+                INetd.IPV6, INetd.CONF, UPSTREAM_IFACE, "hop_limit")).thenReturn("64");
+        final LinkProperties lp = buildIpv6OnlyLinkProperties(UPSTREAM_IFACE);
+        dispatchTetherConnectionChanged(UPSTREAM_IFACE, lp, 1);
+        verify(mRaDaemon).buildNewRa(any(), raParamsCaptor.capture());
+        final RaParams nonCellularParams = raParamsCaptor.getValue();
+        assertEquals(65, nonCellularParams.hopLimit);
+        reset(mRaDaemon);
+
+        dispatchTetherConnectionChanged(UPSTREAM_IFACE, null, 0);
+        verify(mRaDaemon).buildNewRa(any(), raParamsCaptor.capture());
+        final RaParams noUpstream = raParamsCaptor.getValue();
+        assertEquals(65, nonCellularParams.hopLimit);
+        reset(mRaDaemon);
+
+        dispatchTetherConnectionChanged(UPSTREAM_IFACE, lp, -1);
+        verify(mRaDaemon).buildNewRa(any(), raParamsCaptor.capture());
+        final RaParams cellularParams = raParamsCaptor.getValue();
+        assertEquals(63, cellularParams.hopLimit);
+        reset(mRaDaemon);
+    }
+
+    @Test
+    public void testStopObsoleteDhcpServer() throws Exception {
+        final ArgumentCaptor<DhcpServerCallbacks> cbCaptor =
+                ArgumentCaptor.forClass(DhcpServerCallbacks.class);
+        doNothing().when(mDependencies).makeDhcpServer(any(), mDhcpParamsCaptor.capture(),
+                cbCaptor.capture());
+        initStateMachine(TETHERING_WIFI);
+        dispatchCommand(IpServer.CMD_TETHER_REQUESTED, STATE_TETHERED);
+        verify(mDhcpServer, never()).startWithCallbacks(any(), any());
+
+        // No stop dhcp server because dhcp server is not created yet.
+        dispatchCommand(IpServer.CMD_TETHER_UNREQUESTED);
+        verify(mDhcpServer, never()).stop(any());
+
+        // Stop obsolete dhcp server.
+        try {
+            final DhcpServerCallbacks cb = cbCaptor.getValue();
+            cb.onDhcpServerCreated(STATUS_SUCCESS, mDhcpServer);
+            mLooper.dispatchAll();
+        } catch (RemoteException e) {
+            fail(e.getMessage());
+        }
+        verify(mDhcpServer).stop(any());
+    }
+
+    private void assertDhcpServingParams(final DhcpServingParamsParcel params,
+            final IpPrefix prefix) {
+        // Last address byte is random
+        assertTrue(prefix.contains(intToInet4AddressHTH(params.serverAddr)));
+        assertEquals(prefix.getPrefixLength(), params.serverAddrPrefixLength);
+        assertEquals(1, params.defaultRouters.length);
+        assertEquals(params.serverAddr, params.defaultRouters[0]);
+        assertEquals(1, params.dnsServers.length);
+        assertEquals(params.serverAddr, params.dnsServers[0]);
+        assertEquals(DHCP_LEASE_TIME_SECS, params.dhcpLeaseTimeSecs);
+        if (mIpServer.interfaceType() == TETHERING_NCM) {
+            assertTrue(params.changePrefixOnDecline);
+        }
+    }
+
+    private void assertDhcpStarted(IpPrefix expectedPrefix) throws Exception {
+        verify(mDependencies, times(1)).makeDhcpServer(eq(IFACE_NAME), any(), any());
+        verify(mDhcpServer, timeout(MAKE_DHCPSERVER_TIMEOUT_MS).times(1)).startWithCallbacks(
+                any(), any());
+        assertDhcpServingParams(mDhcpParamsCaptor.getValue(), expectedPrefix);
+    }
+
+    /**
+     * Send a command to the state machine under test, and run the event loop to idle.
+     *
+     * @param command One of the IpServer.CMD_* constants.
+     * @param arg1 An additional argument to pass.
+     */
+    private void dispatchCommand(int command, int arg1) {
+        mIpServer.sendMessage(command, arg1);
+        mLooper.dispatchAll();
+    }
+
+    /**
+     * Send a command to the state machine under test, and run the event loop to idle.
+     *
+     * @param command One of the IpServer.CMD_* constants.
+     */
+    private void dispatchCommand(int command) {
+        mIpServer.sendMessage(command);
+        mLooper.dispatchAll();
+    }
+
+    /**
+     * Special override to tell the state machine that the upstream interface has changed.
+     *
+     * @see #dispatchCommand(int)
+     * @param upstreamIface String name of upstream interface (or null)
+     * @param v6lp IPv6 LinkProperties of the upstream interface, or null for an IPv4-only upstream.
+     */
+    private void dispatchTetherConnectionChanged(String upstreamIface, LinkProperties v6lp,
+            int ttlAdjustment) {
+        dispatchTetherConnectionChanged(upstreamIface);
+        mIpServer.sendMessage(IpServer.CMD_IPV6_TETHER_UPDATE, ttlAdjustment, 0, v6lp);
+        mLooper.dispatchAll();
+    }
+
+    private void dispatchTetherConnectionChanged(String upstreamIface) {
+        final InterfaceSet ifs = (upstreamIface != null) ? new InterfaceSet(upstreamIface) : null;
+        mIpServer.sendMessage(IpServer.CMD_TETHER_CONNECTION_CHANGED, ifs);
+        mLooper.dispatchAll();
+    }
+
+    private void assertIPv4AddressAndDirectlyConnectedRoute(LinkProperties lp) {
+        // Find the first IPv4 LinkAddress.
+        LinkAddress addr4 = null;
+        for (LinkAddress addr : lp.getLinkAddresses()) {
+            if (!(addr.getAddress() instanceof Inet4Address)) continue;
+            addr4 = addr;
+            break;
+        }
+        assertNotNull("missing IPv4 address", addr4);
+
+        final IpPrefix destination = new IpPrefix(addr4.getAddress(), addr4.getPrefixLength());
+        // Assert the presence of the associated directly connected route.
+        final RouteInfo directlyConnected = new RouteInfo(destination, null, lp.getInterfaceName(),
+                RouteInfo.RTN_UNICAST);
+        assertTrue("missing directly connected route: '" + directlyConnected.toString() + "'",
+                   lp.getRoutes().contains(directlyConnected));
+    }
+
+    private void assertNoAddressesNorRoutes(LinkProperties lp) {
+        assertTrue(lp.getLinkAddresses().isEmpty());
+        assertTrue(lp.getRoutes().isEmpty());
+        // We also check that interface name is non-empty, because we should
+        // never see an empty interface name in any LinkProperties update.
+        assertFalse(TextUtils.isEmpty(lp.getInterfaceName()));
+    }
+
+    private boolean assertContainsFlag(String[] flags, String match) {
+        for (String flag : flags) {
+            if (flag.equals(match)) return true;
+        }
+        fail("Missing flag: " + match);
+        return false;
+    }
+
+    private boolean assertNotContainsFlag(String[] flags, String match) {
+        for (String flag : flags) {
+            if (flag.equals(match)) {
+                fail("Unexpected flag: " + match);
+                return false;
+            }
+        }
+        return true;
+    }
+
+    @Test @IgnoreUpTo(Build.VERSION_CODES.R)
+    public void dadProxyUpdates() throws Exception {
+        InOrder inOrder = inOrder(mDadProxy);
+        initTetheredStateMachine(TETHERING_WIFI, UPSTREAM_IFACE);
+        inOrder.verify(mDadProxy).setUpstreamIface(UPSTREAM_IFACE_PARAMS);
+
+        // Add an upstream without IPv6.
+        dispatchTetherConnectionChanged(UPSTREAM_IFACE, null, 0);
+        inOrder.verify(mDadProxy).setUpstreamIface(null);
+
+        // Add IPv6 to the upstream.
+        LinkProperties lp = new LinkProperties();
+        lp.setInterfaceName(UPSTREAM_IFACE);
+        dispatchTetherConnectionChanged(UPSTREAM_IFACE, lp, 0);
+        inOrder.verify(mDadProxy).setUpstreamIface(UPSTREAM_IFACE_PARAMS);
+
+        // Change upstream.
+        // New linkproperties is needed, otherwise changing the iface has no impact.
+        LinkProperties lp2 = new LinkProperties();
+        lp2.setInterfaceName(UPSTREAM_IFACE2);
+        dispatchTetherConnectionChanged(UPSTREAM_IFACE2, lp2, 0);
+        inOrder.verify(mDadProxy).setUpstreamIface(UPSTREAM_IFACE_PARAMS2);
+
+        // Lose IPv6 on the upstream...
+        dispatchTetherConnectionChanged(UPSTREAM_IFACE2, null, 0);
+        inOrder.verify(mDadProxy).setUpstreamIface(null);
+
+        // ... and regain it on a different upstream.
+        dispatchTetherConnectionChanged(UPSTREAM_IFACE, lp, 0);
+        inOrder.verify(mDadProxy).setUpstreamIface(UPSTREAM_IFACE_PARAMS);
+
+        // Lose upstream.
+        dispatchTetherConnectionChanged(null, null, 0);
+        inOrder.verify(mDadProxy).setUpstreamIface(null);
+
+        // Regain upstream.
+        dispatchTetherConnectionChanged(UPSTREAM_IFACE, lp, 0);
+        inOrder.verify(mDadProxy).setUpstreamIface(UPSTREAM_IFACE_PARAMS);
+
+        // Stop tethering.
+        mIpServer.stop();
+        mLooper.dispatchAll();
+    }
+
+    private void checkDadProxyEnabled(boolean expectEnabled) throws Exception {
+        initTetheredStateMachine(TETHERING_WIFI, UPSTREAM_IFACE);
+        InOrder inOrder = inOrder(mDadProxy);
+        // Add IPv6 to the upstream.
+        LinkProperties lp = new LinkProperties();
+        lp.setInterfaceName(UPSTREAM_IFACE);
+        if (expectEnabled) {
+            inOrder.verify(mDadProxy).setUpstreamIface(UPSTREAM_IFACE_PARAMS);
+        } else {
+            inOrder.verifyNoMoreInteractions();
+        }
+        // Stop tethering.
+        mIpServer.stop();
+        mLooper.dispatchAll();
+        if (expectEnabled) {
+            inOrder.verify(mDadProxy).stop();
+        }
+        else {
+            verify(mDependencies, never()).getDadProxy(any(), any());
+        }
+    }
+    @Test @IgnoreAfter(Build.VERSION_CODES.R)
+    public void testDadProxyUpdates_DisabledUpToR() throws Exception {
+        checkDadProxyEnabled(false);
+    }
+    @Test @IgnoreUpTo(Build.VERSION_CODES.R)
+    public void testDadProxyUpdates_EnabledAfterR() throws Exception {
+        checkDadProxyEnabled(true);
+    }
+}
diff --git a/Tethering/tests/unit/src/android/net/util/InterfaceSetTest.java b/Tethering/tests/unit/src/android/net/util/InterfaceSetTest.java
new file mode 100644
index 0000000..ea084b6
--- /dev/null
+++ b/Tethering/tests/unit/src/android/net/util/InterfaceSetTest.java
@@ -0,0 +1,61 @@
+/*
+ * Copyright (C) 2018 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package android.net.util;
+
+import static junit.framework.Assert.assertEquals;
+import static junit.framework.Assert.assertFalse;
+import static junit.framework.Assert.assertTrue;
+
+import androidx.test.filters.SmallTest;
+import androidx.test.runner.AndroidJUnit4;
+
+import org.junit.Test;
+import org.junit.runner.RunWith;
+
+@RunWith(AndroidJUnit4.class)
+@SmallTest
+public class InterfaceSetTest {
+    @Test
+    public void testNullNamesIgnored() {
+        final InterfaceSet set = new InterfaceSet(null, "if1", null, "if2", null);
+        assertEquals(2, set.ifnames.size());
+        assertTrue(set.ifnames.contains("if1"));
+        assertTrue(set.ifnames.contains("if2"));
+    }
+
+    @Test
+    public void testToString() {
+        final InterfaceSet set = new InterfaceSet("if1", "if2");
+        final String setString = set.toString();
+        assertTrue(setString.equals("[if1,if2]") || setString.equals("[if2,if1]"));
+    }
+
+    @Test
+    public void testToString_Empty() {
+        final InterfaceSet set = new InterfaceSet(null, null);
+        assertEquals("[]", set.toString());
+    }
+
+    @Test
+    public void testEquals() {
+        assertEquals(new InterfaceSet(null, "if1", "if2"), new InterfaceSet("if2", "if1"));
+        assertEquals(new InterfaceSet(null, null), new InterfaceSet());
+        assertFalse(new InterfaceSet("if1", "if3").equals(new InterfaceSet("if1", "if2")));
+        assertFalse(new InterfaceSet("if1", "if2").equals(new InterfaceSet("if1")));
+        assertFalse(new InterfaceSet().equals(null));
+    }
+}
diff --git a/Tethering/tests/unit/src/android/net/util/TetheringUtilsTest.java b/Tethering/tests/unit/src/android/net/util/TetheringUtilsTest.java
new file mode 100644
index 0000000..91c7771
--- /dev/null
+++ b/Tethering/tests/unit/src/android/net/util/TetheringUtilsTest.java
@@ -0,0 +1,87 @@
+/*
+ * Copyright (C) 2019 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package android.net.util;
+
+import static android.net.TetheringManager.TETHERING_USB;
+import static android.net.TetheringManager.TETHERING_WIFI;
+
+import static junit.framework.Assert.assertFalse;
+import static junit.framework.Assert.assertTrue;
+
+import android.net.LinkAddress;
+import android.net.TetheringRequestParcel;
+
+import androidx.test.filters.SmallTest;
+import androidx.test.runner.AndroidJUnit4;
+
+import com.android.testutils.MiscAsserts;
+
+import org.junit.Before;
+import org.junit.Test;
+import org.junit.runner.RunWith;
+
+@RunWith(AndroidJUnit4.class)
+@SmallTest
+public class TetheringUtilsTest {
+    private static final LinkAddress TEST_SERVER_ADDR = new LinkAddress("192.168.43.1/24");
+    private static final LinkAddress TEST_CLIENT_ADDR = new LinkAddress("192.168.43.5/24");
+    private TetheringRequestParcel mTetheringRequest;
+
+    @Before
+    public void setUp() {
+        mTetheringRequest = makeTetheringRequestParcel();
+    }
+
+    public TetheringRequestParcel makeTetheringRequestParcel() {
+        final TetheringRequestParcel request = new TetheringRequestParcel();
+        request.tetheringType = TETHERING_WIFI;
+        request.localIPv4Address = TEST_SERVER_ADDR;
+        request.staticClientAddress = TEST_CLIENT_ADDR;
+        request.exemptFromEntitlementCheck = false;
+        request.showProvisioningUi = true;
+        return request;
+    }
+
+    @Test
+    public void testIsTetheringRequestEquals() throws Exception {
+        TetheringRequestParcel request = makeTetheringRequestParcel();
+
+        assertTrue(TetheringUtils.isTetheringRequestEquals(mTetheringRequest, mTetheringRequest));
+        assertTrue(TetheringUtils.isTetheringRequestEquals(mTetheringRequest, request));
+        assertTrue(TetheringUtils.isTetheringRequestEquals(null, null));
+        assertFalse(TetheringUtils.isTetheringRequestEquals(mTetheringRequest, null));
+        assertFalse(TetheringUtils.isTetheringRequestEquals(null, mTetheringRequest));
+
+        request = makeTetheringRequestParcel();
+        request.tetheringType = TETHERING_USB;
+        assertFalse(TetheringUtils.isTetheringRequestEquals(mTetheringRequest, request));
+
+        request = makeTetheringRequestParcel();
+        request.localIPv4Address = null;
+        request.staticClientAddress = null;
+        assertFalse(TetheringUtils.isTetheringRequestEquals(mTetheringRequest, request));
+
+        request = makeTetheringRequestParcel();
+        request.exemptFromEntitlementCheck = true;
+        assertFalse(TetheringUtils.isTetheringRequestEquals(mTetheringRequest, request));
+
+        request = makeTetheringRequestParcel();
+        request.showProvisioningUi = false;
+        assertFalse(TetheringUtils.isTetheringRequestEquals(mTetheringRequest, request));
+
+        MiscAsserts.assertFieldCountEquals(5, TetheringRequestParcel.class);
+    }
+}
diff --git a/Tethering/tests/unit/src/android/net/util/VersionedBroadcastListenerTest.java b/Tethering/tests/unit/src/android/net/util/VersionedBroadcastListenerTest.java
new file mode 100644
index 0000000..5a9b6e3
--- /dev/null
+++ b/Tethering/tests/unit/src/android/net/util/VersionedBroadcastListenerTest.java
@@ -0,0 +1,131 @@
+/*
+ * Copyright (C) 2017 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package android.net.util;
+
+import static org.junit.Assert.assertEquals;
+import static org.mockito.Mockito.reset;
+
+import android.content.Context;
+import android.content.Intent;
+import android.content.IntentFilter;
+import android.os.Handler;
+import android.os.Looper;
+import android.os.UserHandle;
+
+import androidx.test.filters.SmallTest;
+import androidx.test.runner.AndroidJUnit4;
+
+import com.android.internal.util.test.BroadcastInterceptingContext;
+
+import org.junit.After;
+import org.junit.Before;
+import org.junit.BeforeClass;
+import org.junit.Test;
+import org.junit.runner.RunWith;
+import org.mockito.Mock;
+import org.mockito.MockitoAnnotations;
+
+@RunWith(AndroidJUnit4.class)
+@SmallTest
+public class VersionedBroadcastListenerTest {
+    private static final String TAG = VersionedBroadcastListenerTest.class.getSimpleName();
+    private static final String ACTION_TEST = "action.test.happy.broadcasts";
+
+    @Mock private Context mContext;
+    private BroadcastInterceptingContext mServiceContext;
+    private Handler mHandler;
+    private VersionedBroadcastListener mListener;
+    private int mCallbackCount;
+
+    private void doCallback() {
+        mCallbackCount++;
+    }
+
+    private class MockContext extends BroadcastInterceptingContext {
+        MockContext(Context base) {
+            super(base);
+        }
+    }
+
+    @BeforeClass
+    public static void setUpBeforeClass() throws Exception {
+        if (Looper.myLooper() == null) {
+            Looper.prepare();
+        }
+    }
+
+    @Before public void setUp() throws Exception {
+        MockitoAnnotations.initMocks(this);
+        reset(mContext);
+        mServiceContext = new MockContext(mContext);
+        mHandler = new Handler(Looper.myLooper());
+        mCallbackCount = 0;
+        final IntentFilter filter = new IntentFilter();
+        filter.addAction(ACTION_TEST);
+        mListener = new VersionedBroadcastListener(
+                TAG, mServiceContext, mHandler, filter, (Intent intent) -> doCallback());
+    }
+
+    @After public void tearDown() throws Exception {
+        if (mListener != null) {
+            mListener.stopListening();
+            mListener = null;
+        }
+    }
+
+    private void sendBroadcast() {
+        final Intent intent = new Intent(ACTION_TEST);
+        mServiceContext.sendStickyBroadcastAsUser(intent, UserHandle.ALL);
+    }
+
+    @Test
+    public void testBasicListening() {
+        assertEquals(0, mCallbackCount);
+        mListener.startListening();
+        for (int i = 0; i < 5; i++) {
+            sendBroadcast();
+            assertEquals(i + 1, mCallbackCount);
+        }
+        mListener.stopListening();
+    }
+
+    @Test
+    public void testBroadcastsBeforeStartAreIgnored() {
+        assertEquals(0, mCallbackCount);
+        for (int i = 0; i < 5; i++) {
+            sendBroadcast();
+            assertEquals(0, mCallbackCount);
+        }
+
+        mListener.startListening();
+        sendBroadcast();
+        assertEquals(1, mCallbackCount);
+    }
+
+    @Test
+    public void testBroadcastsAfterStopAreIgnored() {
+        mListener.startListening();
+        sendBroadcast();
+        assertEquals(1, mCallbackCount);
+        mListener.stopListening();
+
+        for (int i = 0; i < 5; i++) {
+            sendBroadcast();
+            assertEquals(1, mCallbackCount);
+        }
+    }
+}
diff --git a/Tethering/tests/unit/src/com/android/networkstack/tethering/BpfCoordinatorTest.java b/Tethering/tests/unit/src/com/android/networkstack/tethering/BpfCoordinatorTest.java
new file mode 100644
index 0000000..64242ae
--- /dev/null
+++ b/Tethering/tests/unit/src/com/android/networkstack/tethering/BpfCoordinatorTest.java
@@ -0,0 +1,607 @@
+/*
+ * Copyright (C) 2020 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.android.networkstack.tethering;
+
+import static android.net.NetworkStats.DEFAULT_NETWORK_NO;
+import static android.net.NetworkStats.METERED_NO;
+import static android.net.NetworkStats.ROAMING_NO;
+import static android.net.NetworkStats.SET_DEFAULT;
+import static android.net.NetworkStats.TAG_NONE;
+import static android.net.NetworkStats.UID_ALL;
+import static android.net.NetworkStats.UID_TETHERING;
+import static android.net.netstats.provider.NetworkStatsProvider.QUOTA_UNLIMITED;
+
+import static com.android.networkstack.tethering.BpfCoordinator.StatsType;
+import static com.android.networkstack.tethering.BpfCoordinator.StatsType.STATS_PER_IFACE;
+import static com.android.networkstack.tethering.BpfCoordinator.StatsType.STATS_PER_UID;
+import static com.android.networkstack.tethering.TetheringConfiguration.DEFAULT_TETHER_OFFLOAD_POLL_INTERVAL_MS;
+
+import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertNotNull;
+import static org.junit.Assert.assertNull;
+import static org.junit.Assert.fail;
+import static org.mockito.Matchers.any;
+import static org.mockito.Matchers.anyInt;
+import static org.mockito.Matchers.anyLong;
+import static org.mockito.Matchers.anyString;
+import static org.mockito.Mockito.argThat;
+import static org.mockito.Mockito.clearInvocations;
+import static org.mockito.Mockito.inOrder;
+import static org.mockito.Mockito.never;
+import static org.mockito.Mockito.verify;
+import static org.mockito.Mockito.when;
+
+import android.app.usage.NetworkStatsManager;
+import android.net.INetd;
+import android.net.InetAddresses;
+import android.net.MacAddress;
+import android.net.NetworkStats;
+import android.net.TetherOffloadRuleParcel;
+import android.net.TetherStatsParcel;
+import android.net.ip.IpServer;
+import android.net.util.SharedLog;
+import android.os.Handler;
+import android.os.test.TestLooper;
+
+import androidx.annotation.NonNull;
+import androidx.annotation.Nullable;
+import androidx.test.filters.SmallTest;
+import androidx.test.runner.AndroidJUnit4;
+
+import com.android.networkstack.tethering.BpfCoordinator.Ipv6ForwardingRule;
+import com.android.testutils.TestableNetworkStatsProviderCbBinder;
+
+import org.junit.Before;
+import org.junit.Test;
+import org.junit.runner.RunWith;
+import org.mockito.ArgumentCaptor;
+import org.mockito.ArgumentMatcher;
+import org.mockito.InOrder;
+import org.mockito.Mock;
+import org.mockito.MockitoAnnotations;
+
+import java.net.Inet6Address;
+import java.net.InetAddress;
+import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.LinkedHashMap;
+
+@RunWith(AndroidJUnit4.class)
+@SmallTest
+public class BpfCoordinatorTest {
+    private static final int DOWNSTREAM_IFINDEX = 10;
+    private static final MacAddress DOWNSTREAM_MAC = MacAddress.ALL_ZEROS_ADDRESS;
+    private static final InetAddress NEIGH_A = InetAddresses.parseNumericAddress("2001:db8::1");
+    private static final InetAddress NEIGH_B = InetAddresses.parseNumericAddress("2001:db8::2");
+    private static final MacAddress MAC_A = MacAddress.fromString("00:00:00:00:00:0a");
+    private static final MacAddress MAC_B = MacAddress.fromString("11:22:33:00:00:0b");
+
+    @Mock private NetworkStatsManager mStatsManager;
+    @Mock private INetd mNetd;
+    @Mock private IpServer mIpServer;
+    @Mock private TetheringConfiguration mTetherConfig;
+
+    // Late init since methods must be called by the thread that created this object.
+    private TestableNetworkStatsProviderCbBinder mTetherStatsProviderCb;
+    private BpfCoordinator.BpfTetherStatsProvider mTetherStatsProvider;
+    private final ArgumentCaptor<ArrayList> mStringArrayCaptor =
+            ArgumentCaptor.forClass(ArrayList.class);
+    private final TestLooper mTestLooper = new TestLooper();
+    private BpfCoordinator.Dependencies mDeps =
+            new BpfCoordinator.Dependencies() {
+            @NonNull
+            public Handler getHandler() {
+                return new Handler(mTestLooper.getLooper());
+            }
+
+            @NonNull
+            public INetd getNetd() {
+                return mNetd;
+            }
+
+            @NonNull
+            public NetworkStatsManager getNetworkStatsManager() {
+                return mStatsManager;
+            }
+
+            @NonNull
+            public SharedLog getSharedLog() {
+                return new SharedLog("test");
+            }
+
+            @Nullable
+            public TetheringConfiguration getTetherConfig() {
+                return mTetherConfig;
+            }
+    };
+
+    @Before public void setUp() {
+        MockitoAnnotations.initMocks(this);
+        when(mTetherConfig.isBpfOffloadEnabled()).thenReturn(true /* default value */);
+    }
+
+    private void waitForIdle() {
+        mTestLooper.dispatchAll();
+    }
+
+    private void setupFunctioningNetdInterface() throws Exception {
+        when(mNetd.tetherOffloadGetStats()).thenReturn(new TetherStatsParcel[0]);
+    }
+
+    @NonNull
+    private BpfCoordinator makeBpfCoordinator() throws Exception {
+        final BpfCoordinator coordinator = new BpfCoordinator(mDeps);
+        final ArgumentCaptor<BpfCoordinator.BpfTetherStatsProvider>
+                tetherStatsProviderCaptor =
+                ArgumentCaptor.forClass(BpfCoordinator.BpfTetherStatsProvider.class);
+        verify(mStatsManager).registerNetworkStatsProvider(anyString(),
+                tetherStatsProviderCaptor.capture());
+        mTetherStatsProvider = tetherStatsProviderCaptor.getValue();
+        assertNotNull(mTetherStatsProvider);
+        mTetherStatsProviderCb = new TestableNetworkStatsProviderCbBinder();
+        mTetherStatsProvider.setProviderCallbackBinder(mTetherStatsProviderCb);
+        return coordinator;
+    }
+
+    @NonNull
+    private static NetworkStats.Entry buildTestEntry(@NonNull StatsType how,
+            @NonNull String iface, long rxBytes, long rxPackets, long txBytes, long txPackets) {
+        return new NetworkStats.Entry(iface, how == STATS_PER_IFACE ? UID_ALL : UID_TETHERING,
+                SET_DEFAULT, TAG_NONE, METERED_NO, ROAMING_NO, DEFAULT_NETWORK_NO, rxBytes,
+                rxPackets, txBytes, txPackets, 0L);
+    }
+
+    @NonNull
+    private static TetherStatsParcel buildTestTetherStatsParcel(@NonNull Integer ifIndex,
+            long rxBytes, long rxPackets, long txBytes, long txPackets) {
+        final TetherStatsParcel parcel = new TetherStatsParcel();
+        parcel.ifIndex = ifIndex;
+        parcel.rxBytes = rxBytes;
+        parcel.rxPackets = rxPackets;
+        parcel.txBytes = txBytes;
+        parcel.txPackets = txPackets;
+        return parcel;
+    }
+
+    // Set up specific tether stats list and wait for the stats cache is updated by polling thread
+    // in the coordinator. Beware of that it is only used for the default polling interval.
+    private void setTetherOffloadStatsList(TetherStatsParcel[] tetherStatsList) throws Exception {
+        when(mNetd.tetherOffloadGetStats()).thenReturn(tetherStatsList);
+        mTestLooper.moveTimeForward(DEFAULT_TETHER_OFFLOAD_POLL_INTERVAL_MS);
+        waitForIdle();
+    }
+
+    @Test
+    public void testGetForwardedStats() throws Exception {
+        setupFunctioningNetdInterface();
+
+        final BpfCoordinator coordinator = makeBpfCoordinator();
+        coordinator.startPolling();
+
+        final String wlanIface = "wlan0";
+        final Integer wlanIfIndex = 100;
+        final String mobileIface = "rmnet_data0";
+        final Integer mobileIfIndex = 101;
+
+        // Add interface name to lookup table. In realistic case, the upstream interface name will
+        // be added by IpServer when IpServer has received with a new IPv6 upstream update event.
+        coordinator.addUpstreamNameToLookupTable(wlanIfIndex, wlanIface);
+        coordinator.addUpstreamNameToLookupTable(mobileIfIndex, mobileIface);
+
+        // [1] Both interface stats are changed.
+        // Setup the tether stats of wlan and mobile interface. Note that move forward the time of
+        // the looper to make sure the new tether stats has been updated by polling update thread.
+        setTetherOffloadStatsList(new TetherStatsParcel[] {
+                buildTestTetherStatsParcel(wlanIfIndex, 1000, 100, 2000, 200),
+                buildTestTetherStatsParcel(mobileIfIndex, 3000, 300, 4000, 400)});
+
+        final NetworkStats expectedIfaceStats = new NetworkStats(0L, 2)
+                .addEntry(buildTestEntry(STATS_PER_IFACE, wlanIface, 1000, 100, 2000, 200))
+                .addEntry(buildTestEntry(STATS_PER_IFACE, mobileIface, 3000, 300, 4000, 400));
+
+        final NetworkStats expectedUidStats = new NetworkStats(0L, 2)
+                .addEntry(buildTestEntry(STATS_PER_UID, wlanIface, 1000, 100, 2000, 200))
+                .addEntry(buildTestEntry(STATS_PER_UID, mobileIface, 3000, 300, 4000, 400));
+
+        // Force pushing stats update to verify the stats reported.
+        // TODO: Perhaps make #expectNotifyStatsUpdated to use test TetherStatsParcel object for
+        // verifying the notification.
+        mTetherStatsProvider.pushTetherStats();
+        mTetherStatsProviderCb.expectNotifyStatsUpdated(expectedIfaceStats, expectedUidStats);
+
+        // [2] Only one interface stats is changed.
+        // The tether stats of mobile interface is accumulated and The tether stats of wlan
+        // interface is the same.
+        setTetherOffloadStatsList(new TetherStatsParcel[] {
+                buildTestTetherStatsParcel(wlanIfIndex, 1000, 100, 2000, 200),
+                buildTestTetherStatsParcel(mobileIfIndex, 3010, 320, 4030, 440)});
+
+        final NetworkStats expectedIfaceStatsDiff = new NetworkStats(0L, 2)
+                .addEntry(buildTestEntry(STATS_PER_IFACE, wlanIface, 0, 0, 0, 0))
+                .addEntry(buildTestEntry(STATS_PER_IFACE, mobileIface, 10, 20, 30, 40));
+
+        final NetworkStats expectedUidStatsDiff = new NetworkStats(0L, 2)
+                .addEntry(buildTestEntry(STATS_PER_UID, wlanIface, 0, 0, 0, 0))
+                .addEntry(buildTestEntry(STATS_PER_UID, mobileIface, 10, 20, 30, 40));
+
+        // Force pushing stats update to verify that only diff of stats is reported.
+        mTetherStatsProvider.pushTetherStats();
+        mTetherStatsProviderCb.expectNotifyStatsUpdated(expectedIfaceStatsDiff,
+                expectedUidStatsDiff);
+
+        // [3] Stop coordinator.
+        // Shutdown the coordinator and clear the invocation history, especially the
+        // tetherOffloadGetStats() calls.
+        coordinator.stopPolling();
+        clearInvocations(mNetd);
+
+        // Verify the polling update thread stopped.
+        mTestLooper.moveTimeForward(DEFAULT_TETHER_OFFLOAD_POLL_INTERVAL_MS);
+        waitForIdle();
+        verify(mNetd, never()).tetherOffloadGetStats();
+    }
+
+    @Test
+    public void testOnSetAlert() throws Exception {
+        setupFunctioningNetdInterface();
+
+        final BpfCoordinator coordinator = makeBpfCoordinator();
+        coordinator.startPolling();
+
+        final String mobileIface = "rmnet_data0";
+        final Integer mobileIfIndex = 100;
+        coordinator.addUpstreamNameToLookupTable(mobileIfIndex, mobileIface);
+
+        // Verify that set quota to 0 will immediately triggers a callback.
+        mTetherStatsProvider.onSetAlert(0);
+        waitForIdle();
+        mTetherStatsProviderCb.expectNotifyAlertReached();
+
+        // Verify that notifyAlertReached never fired if quota is not yet reached.
+        when(mNetd.tetherOffloadGetStats()).thenReturn(
+                new TetherStatsParcel[] {buildTestTetherStatsParcel(mobileIfIndex, 0, 0, 0, 0)});
+        mTetherStatsProvider.onSetAlert(100);
+        mTestLooper.moveTimeForward(DEFAULT_TETHER_OFFLOAD_POLL_INTERVAL_MS);
+        waitForIdle();
+        mTetherStatsProviderCb.assertNoCallback();
+
+        // Verify that notifyAlertReached fired when quota is reached.
+        when(mNetd.tetherOffloadGetStats()).thenReturn(
+                new TetherStatsParcel[] {buildTestTetherStatsParcel(mobileIfIndex, 50, 0, 50, 0)});
+        mTestLooper.moveTimeForward(DEFAULT_TETHER_OFFLOAD_POLL_INTERVAL_MS);
+        waitForIdle();
+        mTetherStatsProviderCb.expectNotifyAlertReached();
+
+        // Verify that set quota with UNLIMITED won't trigger any callback.
+        mTetherStatsProvider.onSetAlert(QUOTA_UNLIMITED);
+        mTestLooper.moveTimeForward(DEFAULT_TETHER_OFFLOAD_POLL_INTERVAL_MS);
+        waitForIdle();
+        mTetherStatsProviderCb.assertNoCallback();
+    }
+
+    // The custom ArgumentMatcher simply comes from IpServerTest.
+    // TODO: move both of them into a common utility class for reusing the code.
+    private static class TetherOffloadRuleParcelMatcher implements
+            ArgumentMatcher<TetherOffloadRuleParcel> {
+        public final int upstreamIfindex;
+        public final int downstreamIfindex;
+        public final Inet6Address address;
+        public final MacAddress srcMac;
+        public final MacAddress dstMac;
+
+        TetherOffloadRuleParcelMatcher(@NonNull Ipv6ForwardingRule rule) {
+            upstreamIfindex = rule.upstreamIfindex;
+            downstreamIfindex = rule.downstreamIfindex;
+            address = rule.address;
+            srcMac = rule.srcMac;
+            dstMac = rule.dstMac;
+        }
+
+        public boolean matches(@NonNull TetherOffloadRuleParcel parcel) {
+            return upstreamIfindex == parcel.inputInterfaceIndex
+                    && (downstreamIfindex == parcel.outputInterfaceIndex)
+                    && Arrays.equals(address.getAddress(), parcel.destination)
+                    && (128 == parcel.prefixLength)
+                    && Arrays.equals(srcMac.toByteArray(), parcel.srcL2Address)
+                    && Arrays.equals(dstMac.toByteArray(), parcel.dstL2Address);
+        }
+
+        public String toString() {
+            return String.format("TetherOffloadRuleParcelMatcher(%d, %d, %s, %s, %s",
+                    upstreamIfindex, downstreamIfindex, address.getHostAddress(), srcMac, dstMac);
+        }
+    }
+
+    @NonNull
+    private TetherOffloadRuleParcel matches(@NonNull Ipv6ForwardingRule rule) {
+        return argThat(new TetherOffloadRuleParcelMatcher(rule));
+    }
+
+    @NonNull
+    private static Ipv6ForwardingRule buildTestForwardingRule(
+            int upstreamIfindex, @NonNull InetAddress address, @NonNull MacAddress dstMac) {
+        return new Ipv6ForwardingRule(upstreamIfindex, DOWNSTREAM_IFINDEX, (Inet6Address) address,
+                DOWNSTREAM_MAC, dstMac);
+    }
+
+    @Test
+    public void testSetDataLimit() throws Exception {
+        setupFunctioningNetdInterface();
+
+        final BpfCoordinator coordinator = makeBpfCoordinator();
+
+        final String mobileIface = "rmnet_data0";
+        final Integer mobileIfIndex = 100;
+        coordinator.addUpstreamNameToLookupTable(mobileIfIndex, mobileIface);
+
+        // [1] Default limit.
+        // Set the unlimited quota as default if the service has never applied a data limit for a
+        // given upstream. Note that the data limit only be applied on an upstream which has rules.
+        final Ipv6ForwardingRule rule = buildTestForwardingRule(mobileIfIndex, NEIGH_A, MAC_A);
+        final InOrder inOrder = inOrder(mNetd);
+        coordinator.tetherOffloadRuleAdd(mIpServer, rule);
+        inOrder.verify(mNetd).tetherOffloadRuleAdd(matches(rule));
+        inOrder.verify(mNetd).tetherOffloadSetInterfaceQuota(mobileIfIndex, QUOTA_UNLIMITED);
+        inOrder.verifyNoMoreInteractions();
+
+        // [2] Specific limit.
+        // Applying the data limit boundary {min, 1gb, max, infinity} on current upstream.
+        for (final long quota : new long[] {0, 1048576000, Long.MAX_VALUE, QUOTA_UNLIMITED}) {
+            mTetherStatsProvider.onSetLimit(mobileIface, quota);
+            waitForIdle();
+            inOrder.verify(mNetd).tetherOffloadSetInterfaceQuota(mobileIfIndex, quota);
+            inOrder.verifyNoMoreInteractions();
+        }
+
+        // [3] Invalid limit.
+        // The valid range of quota is 0..max_int64 or -1 (unlimited).
+        final long invalidLimit = Long.MIN_VALUE;
+        try {
+            mTetherStatsProvider.onSetLimit(mobileIface, invalidLimit);
+            waitForIdle();
+            fail("No exception thrown for invalid limit " + invalidLimit + ".");
+        } catch (IllegalArgumentException expected) {
+            assertEquals(expected.getMessage(), "invalid quota value " + invalidLimit);
+        }
+    }
+
+    // TODO: Test the case in which the rules are changed from different IpServer objects.
+    @Test
+    public void testSetDataLimitOnRuleChange() throws Exception {
+        setupFunctioningNetdInterface();
+
+        final BpfCoordinator coordinator = makeBpfCoordinator();
+
+        final String mobileIface = "rmnet_data0";
+        final Integer mobileIfIndex = 100;
+        coordinator.addUpstreamNameToLookupTable(mobileIfIndex, mobileIface);
+
+        // Applying a data limit to the current upstream does not take any immediate action.
+        // The data limit could be only set on an upstream which has rules.
+        final long limit = 12345;
+        final InOrder inOrder = inOrder(mNetd);
+        mTetherStatsProvider.onSetLimit(mobileIface, limit);
+        waitForIdle();
+        inOrder.verify(mNetd, never()).tetherOffloadSetInterfaceQuota(anyInt(), anyLong());
+
+        // Adding the first rule on current upstream immediately sends the quota to netd.
+        final Ipv6ForwardingRule ruleA = buildTestForwardingRule(mobileIfIndex, NEIGH_A, MAC_A);
+        coordinator.tetherOffloadRuleAdd(mIpServer, ruleA);
+        inOrder.verify(mNetd).tetherOffloadRuleAdd(matches(ruleA));
+        inOrder.verify(mNetd).tetherOffloadSetInterfaceQuota(mobileIfIndex, limit);
+        inOrder.verifyNoMoreInteractions();
+
+        // Adding the second rule on current upstream does not send the quota to netd.
+        final Ipv6ForwardingRule ruleB = buildTestForwardingRule(mobileIfIndex, NEIGH_B, MAC_B);
+        coordinator.tetherOffloadRuleAdd(mIpServer, ruleB);
+        inOrder.verify(mNetd).tetherOffloadRuleAdd(matches(ruleB));
+        inOrder.verify(mNetd, never()).tetherOffloadSetInterfaceQuota(anyInt(), anyLong());
+
+        // Removing the second rule on current upstream does not send the quota to netd.
+        coordinator.tetherOffloadRuleRemove(mIpServer, ruleB);
+        inOrder.verify(mNetd).tetherOffloadRuleRemove(matches(ruleB));
+        inOrder.verify(mNetd, never()).tetherOffloadSetInterfaceQuota(anyInt(), anyLong());
+
+        // Removing the last rule on current upstream immediately sends the cleanup stuff to netd.
+        when(mNetd.tetherOffloadGetAndClearStats(mobileIfIndex))
+                .thenReturn(buildTestTetherStatsParcel(mobileIfIndex, 0, 0, 0, 0));
+        coordinator.tetherOffloadRuleRemove(mIpServer, ruleA);
+        inOrder.verify(mNetd).tetherOffloadRuleRemove(matches(ruleA));
+        inOrder.verify(mNetd).tetherOffloadGetAndClearStats(mobileIfIndex);
+        inOrder.verifyNoMoreInteractions();
+    }
+
+    @Test
+    public void testTetherOffloadRuleUpdateAndClear() throws Exception {
+        setupFunctioningNetdInterface();
+
+        final BpfCoordinator coordinator = makeBpfCoordinator();
+
+        final String ethIface = "eth1";
+        final String mobileIface = "rmnet_data0";
+        final Integer ethIfIndex = 100;
+        final Integer mobileIfIndex = 101;
+        coordinator.addUpstreamNameToLookupTable(ethIfIndex, ethIface);
+        coordinator.addUpstreamNameToLookupTable(mobileIfIndex, mobileIface);
+
+        final InOrder inOrder = inOrder(mNetd);
+
+        // Before the rule test, here are the additional actions while the rules are changed.
+        // - After adding the first rule on a given upstream, the coordinator adds a data limit.
+        //   If the service has never applied the data limit, set an unlimited quota as default.
+        // - After removing the last rule on a given upstream, the coordinator gets the last stats.
+        //   Then, it clears the stats and the limit entry from BPF maps.
+        // See tetherOffloadRule{Add, Remove, Clear, Clean}.
+
+        // [1] Adding rules on the upstream Ethernet.
+        // Note that the default data limit is applied after the first rule is added.
+        final Ipv6ForwardingRule ethernetRuleA = buildTestForwardingRule(
+                ethIfIndex, NEIGH_A, MAC_A);
+        final Ipv6ForwardingRule ethernetRuleB = buildTestForwardingRule(
+                ethIfIndex, NEIGH_B, MAC_B);
+
+        coordinator.tetherOffloadRuleAdd(mIpServer, ethernetRuleA);
+        inOrder.verify(mNetd).tetherOffloadRuleAdd(matches(ethernetRuleA));
+        inOrder.verify(mNetd).tetherOffloadSetInterfaceQuota(ethIfIndex, QUOTA_UNLIMITED);
+
+        coordinator.tetherOffloadRuleAdd(mIpServer, ethernetRuleB);
+        inOrder.verify(mNetd).tetherOffloadRuleAdd(matches(ethernetRuleB));
+
+        // [2] Update the existing rules from Ethernet to cellular.
+        final Ipv6ForwardingRule mobileRuleA = buildTestForwardingRule(
+                mobileIfIndex, NEIGH_A, MAC_A);
+        final Ipv6ForwardingRule mobileRuleB = buildTestForwardingRule(
+                mobileIfIndex, NEIGH_B, MAC_B);
+        when(mNetd.tetherOffloadGetAndClearStats(ethIfIndex))
+                .thenReturn(buildTestTetherStatsParcel(ethIfIndex, 10, 20, 30, 40));
+
+        // Update the existing rules for upstream changes. The rules are removed and re-added one
+        // by one for updating upstream interface index by #tetherOffloadRuleUpdate.
+        coordinator.tetherOffloadRuleUpdate(mIpServer, mobileIfIndex);
+        inOrder.verify(mNetd).tetherOffloadRuleRemove(matches(ethernetRuleA));
+        inOrder.verify(mNetd).tetherOffloadRuleAdd(matches(mobileRuleA));
+        inOrder.verify(mNetd).tetherOffloadSetInterfaceQuota(mobileIfIndex, QUOTA_UNLIMITED);
+        inOrder.verify(mNetd).tetherOffloadRuleRemove(matches(ethernetRuleB));
+        inOrder.verify(mNetd).tetherOffloadGetAndClearStats(ethIfIndex);
+        inOrder.verify(mNetd).tetherOffloadRuleAdd(matches(mobileRuleB));
+
+        // [3] Clear all rules for a given IpServer.
+        when(mNetd.tetherOffloadGetAndClearStats(mobileIfIndex))
+                .thenReturn(buildTestTetherStatsParcel(mobileIfIndex, 50, 60, 70, 80));
+        coordinator.tetherOffloadRuleClear(mIpServer);
+        inOrder.verify(mNetd).tetherOffloadRuleRemove(matches(mobileRuleA));
+        inOrder.verify(mNetd).tetherOffloadRuleRemove(matches(mobileRuleB));
+        inOrder.verify(mNetd).tetherOffloadGetAndClearStats(mobileIfIndex);
+
+        // [4] Force pushing stats update to verify that the last diff of stats is reported on all
+        // upstreams.
+        mTetherStatsProvider.pushTetherStats();
+        mTetherStatsProviderCb.expectNotifyStatsUpdated(
+                new NetworkStats(0L, 2)
+                .addEntry(buildTestEntry(STATS_PER_IFACE, ethIface, 10, 20, 30, 40))
+                .addEntry(buildTestEntry(STATS_PER_IFACE, mobileIface, 50, 60, 70, 80)),
+                new NetworkStats(0L, 2)
+                .addEntry(buildTestEntry(STATS_PER_UID, ethIface, 10, 20, 30, 40))
+                .addEntry(buildTestEntry(STATS_PER_UID, mobileIface, 50, 60, 70, 80)));
+    }
+
+    @Test
+    public void testTetheringConfigDisable() throws Exception {
+        setupFunctioningNetdInterface();
+        when(mTetherConfig.isBpfOffloadEnabled()).thenReturn(false);
+
+        final BpfCoordinator coordinator = makeBpfCoordinator();
+        coordinator.startPolling();
+
+        // The tether stats polling task should not be scheduled.
+        mTestLooper.moveTimeForward(DEFAULT_TETHER_OFFLOAD_POLL_INTERVAL_MS);
+        waitForIdle();
+        verify(mNetd, never()).tetherOffloadGetStats();
+
+        // The interface name lookup table can't be added.
+        final String iface = "rmnet_data0";
+        final Integer ifIndex = 100;
+        coordinator.addUpstreamNameToLookupTable(ifIndex, iface);
+        assertEquals(0, coordinator.getInterfaceNamesForTesting().size());
+
+        // The rule can't be added.
+        final InetAddress neigh = InetAddresses.parseNumericAddress("2001:db8::1");
+        final MacAddress mac = MacAddress.fromString("00:00:00:00:00:0a");
+        final Ipv6ForwardingRule rule = buildTestForwardingRule(ifIndex, neigh, mac);
+        coordinator.tetherOffloadRuleAdd(mIpServer, rule);
+        verify(mNetd, never()).tetherOffloadRuleAdd(any());
+        LinkedHashMap<Inet6Address, Ipv6ForwardingRule> rules =
+                coordinator.getForwardingRulesForTesting().get(mIpServer);
+        assertNull(rules);
+
+        // The rule can't be removed. This is not a realistic case because adding rule is not
+        // allowed. That implies no rule could be removed, cleared or updated. Verify these
+        // cases just in case.
+        rules = new LinkedHashMap<Inet6Address, Ipv6ForwardingRule>();
+        rules.put(rule.address, rule);
+        coordinator.getForwardingRulesForTesting().put(mIpServer, rules);
+        coordinator.tetherOffloadRuleRemove(mIpServer, rule);
+        verify(mNetd, never()).tetherOffloadRuleRemove(any());
+        rules = coordinator.getForwardingRulesForTesting().get(mIpServer);
+        assertNotNull(rules);
+        assertEquals(1, rules.size());
+
+        // The rule can't be cleared.
+        coordinator.tetherOffloadRuleClear(mIpServer);
+        verify(mNetd, never()).tetherOffloadRuleRemove(any());
+        rules = coordinator.getForwardingRulesForTesting().get(mIpServer);
+        assertNotNull(rules);
+        assertEquals(1, rules.size());
+
+        // The rule can't be updated.
+        coordinator.tetherOffloadRuleUpdate(mIpServer, rule.upstreamIfindex + 1 /* new */);
+        verify(mNetd, never()).tetherOffloadRuleRemove(any());
+        verify(mNetd, never()).tetherOffloadRuleAdd(any());
+        rules = coordinator.getForwardingRulesForTesting().get(mIpServer);
+        assertNotNull(rules);
+        assertEquals(1, rules.size());
+    }
+
+    @Test
+    public void testTetheringConfigSetPollingInterval() throws Exception {
+        setupFunctioningNetdInterface();
+
+        final BpfCoordinator coordinator = makeBpfCoordinator();
+
+        // [1] The default polling interval.
+        coordinator.startPolling();
+        assertEquals(DEFAULT_TETHER_OFFLOAD_POLL_INTERVAL_MS, coordinator.getPollingInterval());
+        coordinator.stopPolling();
+
+        // [2] Expect the invalid polling interval isn't applied. The valid range of interval is
+        // DEFAULT_TETHER_OFFLOAD_POLL_INTERVAL_MS..max_long.
+        for (final int interval
+                : new int[] {0, 100, DEFAULT_TETHER_OFFLOAD_POLL_INTERVAL_MS - 1}) {
+            when(mTetherConfig.getOffloadPollInterval()).thenReturn(interval);
+            coordinator.startPolling();
+            assertEquals(DEFAULT_TETHER_OFFLOAD_POLL_INTERVAL_MS, coordinator.getPollingInterval());
+            coordinator.stopPolling();
+        }
+
+        // [3] Set a specific polling interval which is larger than default value.
+        // Use a large polling interval to avoid flaky test because the time forwarding
+        // approximation is used to verify the scheduled time of the polling thread.
+        final int pollingInterval = 100_000;
+        when(mTetherConfig.getOffloadPollInterval()).thenReturn(pollingInterval);
+        coordinator.startPolling();
+
+        // Expect the specific polling interval to be applied.
+        assertEquals(pollingInterval, coordinator.getPollingInterval());
+
+        // Start on a new polling time slot.
+        mTestLooper.moveTimeForward(pollingInterval);
+        waitForIdle();
+        clearInvocations(mNetd);
+
+        // Move time forward to 90% polling interval time. Expect that the polling thread has not
+        // scheduled yet.
+        mTestLooper.moveTimeForward((long) (pollingInterval * 0.9));
+        waitForIdle();
+        verify(mNetd, never()).tetherOffloadGetStats();
+
+        // Move time forward to the remaining 10% polling interval time. Expect that the polling
+        // thread has scheduled.
+        mTestLooper.moveTimeForward((long) (pollingInterval * 0.1));
+        waitForIdle();
+        verify(mNetd).tetherOffloadGetStats();
+    }
+}
diff --git a/Tethering/tests/unit/src/com/android/networkstack/tethering/ConnectedClientsTrackerTest.kt b/Tethering/tests/unit/src/com/android/networkstack/tethering/ConnectedClientsTrackerTest.kt
new file mode 100644
index 0000000..d915354
--- /dev/null
+++ b/Tethering/tests/unit/src/com/android/networkstack/tethering/ConnectedClientsTrackerTest.kt
@@ -0,0 +1,162 @@
+/*
+ * Copyright (C) 2020 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.android.networkstack.tethering
+
+import android.net.LinkAddress
+import android.net.MacAddress
+import android.net.TetheredClient
+import android.net.TetheredClient.AddressInfo
+import android.net.TetheringManager.TETHERING_USB
+import android.net.TetheringManager.TETHERING_WIFI
+import android.net.ip.IpServer
+import android.net.wifi.WifiClient
+import androidx.test.filters.SmallTest
+import androidx.test.runner.AndroidJUnit4
+import org.junit.Test
+import org.junit.runner.RunWith
+import org.mockito.Mockito.doReturn
+import org.mockito.Mockito.mock
+import kotlin.test.assertEquals
+import kotlin.test.assertFalse
+import kotlin.test.assertTrue
+
+@RunWith(AndroidJUnit4::class)
+@SmallTest
+class ConnectedClientsTrackerTest {
+
+    private val server1 = mock(IpServer::class.java)
+    private val server2 = mock(IpServer::class.java)
+    private val servers = listOf(server1, server2)
+
+    private val clock = TestClock(1324L)
+
+    private val client1Addr = MacAddress.fromString("01:23:45:67:89:0A")
+    private val client1 = TetheredClient(client1Addr, listOf(
+            makeAddrInfo("192.168.43.44/32", null /* hostname */, clock.time + 20)),
+            TETHERING_WIFI)
+    private val wifiClient1 = makeWifiClient(client1Addr)
+    private val client2Addr = MacAddress.fromString("02:34:56:78:90:AB")
+    private val client2Exp30AddrInfo = makeAddrInfo(
+            "192.168.43.45/32", "my_hostname", clock.time + 30)
+    private val client2 = TetheredClient(client2Addr, listOf(
+            client2Exp30AddrInfo,
+            makeAddrInfo("2001:db8:12::34/72", "other_hostname", clock.time + 10)),
+            TETHERING_WIFI)
+    private val wifiClient2 = makeWifiClient(client2Addr)
+    private val client3Addr = MacAddress.fromString("03:45:67:89:0A:BC")
+    private val client3 = TetheredClient(client3Addr,
+            listOf(makeAddrInfo("2001:db8:34::34/72", "other_other_hostname", clock.time + 10)),
+            TETHERING_USB)
+
+    private fun makeAddrInfo(addr: String, hostname: String?, expTime: Long) =
+            LinkAddress(addr).let {
+                AddressInfo(LinkAddress(it.address, it.prefixLength, it.flags, it.scope,
+                        expTime /* deprecationTime */, expTime /* expirationTime */), hostname)
+            }
+
+    @Test
+    fun testUpdateConnectedClients() {
+        doReturn(emptyList<TetheredClient>()).`when`(server1).allLeases
+        doReturn(emptyList<TetheredClient>()).`when`(server2).allLeases
+
+        val tracker = ConnectedClientsTracker(clock)
+        assertFalse(tracker.updateConnectedClients(servers, null))
+
+        // Obtain a lease for client 1
+        doReturn(listOf(client1)).`when`(server1).allLeases
+        assertSameClients(listOf(client1), assertNewClients(tracker, servers, listOf(wifiClient1)))
+
+        // Client 2 L2-connected, no lease yet
+        val client2WithoutAddr = TetheredClient(client2Addr, emptyList(), TETHERING_WIFI)
+        assertSameClients(listOf(client1, client2WithoutAddr),
+                assertNewClients(tracker, servers, listOf(wifiClient1, wifiClient2)))
+
+        // Client 2 lease obtained
+        doReturn(listOf(client1, client2)).`when`(server1).allLeases
+        assertSameClients(listOf(client1, client2), assertNewClients(tracker, servers, null))
+
+        // Client 3 lease obtained
+        doReturn(listOf(client3)).`when`(server2).allLeases
+        assertSameClients(listOf(client1, client2, client3),
+                assertNewClients(tracker, servers, null))
+
+        // Client 2 L2-disconnected
+        assertSameClients(listOf(client1, client3),
+                assertNewClients(tracker, servers, listOf(wifiClient1)))
+
+        // Client 1 L2-disconnected
+        assertSameClients(listOf(client3), assertNewClients(tracker, servers, emptyList()))
+
+        // Client 1 comes back
+        assertSameClients(listOf(client1, client3),
+                assertNewClients(tracker, servers, listOf(wifiClient1)))
+
+        // Leases lost, client 1 still L2-connected
+        doReturn(emptyList<TetheredClient>()).`when`(server1).allLeases
+        doReturn(emptyList<TetheredClient>()).`when`(server2).allLeases
+        assertSameClients(listOf(TetheredClient(client1Addr, emptyList(), TETHERING_WIFI)),
+                assertNewClients(tracker, servers, null))
+    }
+
+    @Test
+    fun testUpdateConnectedClients_LeaseExpiration() {
+        val tracker = ConnectedClientsTracker(clock)
+        doReturn(listOf(client1, client2)).`when`(server1).allLeases
+        doReturn(listOf(client3)).`when`(server2).allLeases
+        assertSameClients(listOf(client1, client2, client3), assertNewClients(
+                tracker, servers, listOf(wifiClient1, wifiClient2)))
+
+        clock.time += 20
+        // Client 3 has no remaining lease: removed
+        val expectedClients = listOf(
+                // Client 1 has no remaining lease but is L2-connected
+                TetheredClient(client1Addr, emptyList(), TETHERING_WIFI),
+                // Client 2 has some expired leases
+                TetheredClient(
+                        client2Addr,
+                        // Only the "t + 30" address is left, the "t + 10" address expired
+                        listOf(client2Exp30AddrInfo),
+                        TETHERING_WIFI))
+        assertSameClients(expectedClients, assertNewClients(tracker, servers, null))
+    }
+
+    private fun assertNewClients(
+        tracker: ConnectedClientsTracker,
+        ipServers: Iterable<IpServer>,
+        wifiClients: List<WifiClient>?
+    ): List<TetheredClient> {
+        assertTrue(tracker.updateConnectedClients(ipServers, wifiClients))
+        return tracker.lastTetheredClients
+    }
+
+    private fun assertSameClients(expected: List<TetheredClient>, actual: List<TetheredClient>) {
+        val expectedSet = HashSet(expected)
+        assertEquals(expected.size, expectedSet.size)
+        assertEquals(expectedSet, HashSet(actual))
+    }
+
+    private fun makeWifiClient(macAddr: MacAddress): WifiClient {
+        // Use a mock WifiClient as the constructor is not part of the WiFi module exported API.
+        return mock(WifiClient::class.java).apply { doReturn(macAddr).`when`(this).macAddress }
+    }
+
+    private class TestClock(var time: Long) : ConnectedClientsTracker.Clock() {
+        override fun elapsedRealtime(): Long {
+            return time
+        }
+    }
+}
diff --git a/Tethering/tests/unit/src/com/android/networkstack/tethering/EntitlementManagerTest.java b/Tethering/tests/unit/src/com/android/networkstack/tethering/EntitlementManagerTest.java
new file mode 100644
index 0000000..354e753
--- /dev/null
+++ b/Tethering/tests/unit/src/com/android/networkstack/tethering/EntitlementManagerTest.java
@@ -0,0 +1,623 @@
+/*
+ * Copyright (C) 2018 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.android.networkstack.tethering;
+
+import static android.net.TetheringConstants.EXTRA_ADD_TETHER_TYPE;
+import static android.net.TetheringConstants.EXTRA_PROVISION_CALLBACK;
+import static android.net.TetheringConstants.EXTRA_RUN_PROVISION;
+import static android.net.TetheringConstants.EXTRA_TETHER_PROVISIONING_RESPONSE;
+import static android.net.TetheringConstants.EXTRA_TETHER_SILENT_PROVISIONING_ACTION;
+import static android.net.TetheringConstants.EXTRA_TETHER_SUBID;
+import static android.net.TetheringConstants.EXTRA_TETHER_UI_PROVISIONING_APP_NAME;
+import static android.net.TetheringManager.TETHERING_BLUETOOTH;
+import static android.net.TetheringManager.TETHERING_ETHERNET;
+import static android.net.TetheringManager.TETHERING_INVALID;
+import static android.net.TetheringManager.TETHERING_USB;
+import static android.net.TetheringManager.TETHERING_WIFI;
+import static android.net.TetheringManager.TETHERING_WIFI_P2P;
+import static android.net.TetheringManager.TETHER_ERROR_ENTITLEMENT_UNKNOWN;
+import static android.net.TetheringManager.TETHER_ERROR_NO_ERROR;
+import static android.net.TetheringManager.TETHER_ERROR_PROVISIONING_FAILED;
+import static android.provider.DeviceConfig.NAMESPACE_CONNECTIVITY;
+import static android.telephony.SubscriptionManager.INVALID_SUBSCRIPTION_ID;
+
+import static com.android.dx.mockito.inline.extended.ExtendedMockito.doReturn;
+import static com.android.dx.mockito.inline.extended.ExtendedMockito.mockitoSession;
+
+import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertFalse;
+import static org.junit.Assert.assertTrue;
+import static org.mockito.Matchers.anyBoolean;
+import static org.mockito.Matchers.anyInt;
+import static org.mockito.Matchers.anyString;
+import static org.mockito.Matchers.eq;
+import static org.mockito.Mockito.inOrder;
+import static org.mockito.Mockito.spy;
+import static org.mockito.Mockito.times;
+import static org.mockito.Mockito.verify;
+import static org.mockito.Mockito.when;
+
+import android.content.Context;
+import android.content.Intent;
+import android.content.res.Resources;
+import android.net.util.SharedLog;
+import android.os.Bundle;
+import android.os.Handler;
+import android.os.PersistableBundle;
+import android.os.ResultReceiver;
+import android.os.SystemProperties;
+import android.os.test.TestLooper;
+import android.provider.DeviceConfig;
+import android.provider.Settings;
+import android.telephony.CarrierConfigManager;
+
+import androidx.test.filters.SmallTest;
+import androidx.test.runner.AndroidJUnit4;
+
+import com.android.internal.util.test.BroadcastInterceptingContext;
+
+import org.junit.After;
+import org.junit.Before;
+import org.junit.Test;
+import org.junit.runner.RunWith;
+import org.mockito.InOrder;
+import org.mockito.Mock;
+import org.mockito.MockitoAnnotations;
+import org.mockito.MockitoSession;
+import org.mockito.quality.Strictness;
+
+@RunWith(AndroidJUnit4.class)
+@SmallTest
+public final class EntitlementManagerTest {
+
+    private static final String[] PROVISIONING_APP_NAME = {"some", "app"};
+    private static final String PROVISIONING_NO_UI_APP_NAME = "no_ui_app";
+    private static final String PROVISIONING_APP_RESPONSE = "app_response";
+
+    @Mock private CarrierConfigManager mCarrierConfigManager;
+    @Mock private Context mContext;
+    @Mock private Resources mResources;
+    @Mock private SharedLog mLog;
+    @Mock private EntitlementManager.OnUiEntitlementFailedListener mEntitlementFailedListener;
+
+    // Like so many Android system APIs, these cannot be mocked because it is marked final.
+    // We have to use the real versions.
+    private final PersistableBundle mCarrierConfig = new PersistableBundle();
+    private final TestLooper mLooper = new TestLooper();
+    private Context mMockContext;
+    private Runnable mPermissionChangeCallback;
+
+    private WrappedEntitlementManager mEnMgr;
+    private TetheringConfiguration mConfig;
+    private MockitoSession mMockingSession;
+
+    private class MockContext extends BroadcastInterceptingContext {
+        MockContext(Context base) {
+            super(base);
+        }
+
+        @Override
+        public Resources getResources() {
+            return mResources;
+        }
+    }
+
+    public class WrappedEntitlementManager extends EntitlementManager {
+        public int fakeEntitlementResult = TETHER_ERROR_ENTITLEMENT_UNKNOWN;
+        public int uiProvisionCount = 0;
+        public int silentProvisionCount = 0;
+
+        public WrappedEntitlementManager(Context ctx, Handler h, SharedLog log,
+                Runnable callback) {
+            super(ctx, h, log, callback);
+        }
+
+        public void reset() {
+            fakeEntitlementResult = TETHER_ERROR_ENTITLEMENT_UNKNOWN;
+            uiProvisionCount = 0;
+            silentProvisionCount = 0;
+        }
+
+        @Override
+        protected Intent runUiTetherProvisioning(int type,
+                final TetheringConfiguration config, final ResultReceiver receiver) {
+            Intent intent = super.runUiTetherProvisioning(type, config, receiver);
+            assertUiTetherProvisioningIntent(type, config, receiver, intent);
+            uiProvisionCount++;
+            receiver.send(fakeEntitlementResult, null);
+            return intent;
+        }
+
+        private void assertUiTetherProvisioningIntent(int type, final TetheringConfiguration config,
+                final ResultReceiver receiver, final Intent intent) {
+            assertEquals(Settings.ACTION_TETHER_PROVISIONING_UI, intent.getAction());
+            assertEquals(type, intent.getIntExtra(EXTRA_ADD_TETHER_TYPE, TETHERING_INVALID));
+            final String[] appName = intent.getStringArrayExtra(
+                    EXTRA_TETHER_UI_PROVISIONING_APP_NAME);
+            assertEquals(PROVISIONING_APP_NAME.length, appName.length);
+            for (int i = 0; i < PROVISIONING_APP_NAME.length; i++) {
+                assertEquals(PROVISIONING_APP_NAME[i], appName[i]);
+            }
+            assertEquals(receiver, intent.getParcelableExtra(EXTRA_PROVISION_CALLBACK));
+            assertEquals(config.activeDataSubId,
+                    intent.getIntExtra(EXTRA_TETHER_SUBID, INVALID_SUBSCRIPTION_ID));
+        }
+
+        @Override
+        protected Intent runSilentTetherProvisioning(int type,
+                final TetheringConfiguration config) {
+            Intent intent = super.runSilentTetherProvisioning(type, config);
+            assertSilentTetherProvisioning(type, config, intent);
+            silentProvisionCount++;
+            addDownstreamMapping(type, fakeEntitlementResult);
+            return intent;
+        }
+
+        private void assertSilentTetherProvisioning(int type, final TetheringConfiguration config,
+                final Intent intent) {
+            assertEquals(type, intent.getIntExtra(EXTRA_ADD_TETHER_TYPE, TETHERING_INVALID));
+            assertEquals(true, intent.getBooleanExtra(EXTRA_RUN_PROVISION, false));
+            assertEquals(PROVISIONING_NO_UI_APP_NAME,
+                    intent.getStringExtra(EXTRA_TETHER_SILENT_PROVISIONING_ACTION));
+            assertEquals(PROVISIONING_APP_RESPONSE,
+                    intent.getStringExtra(EXTRA_TETHER_PROVISIONING_RESPONSE));
+            assertTrue(intent.hasExtra(EXTRA_PROVISION_CALLBACK));
+            assertEquals(config.activeDataSubId,
+                    intent.getIntExtra(EXTRA_TETHER_SUBID, INVALID_SUBSCRIPTION_ID));
+        }
+    }
+
+    @Before
+    public void setUp() {
+        MockitoAnnotations.initMocks(this);
+        mMockingSession = mockitoSession()
+                .initMocks(this)
+                .mockStatic(SystemProperties.class)
+                .mockStatic(DeviceConfig.class)
+                .strictness(Strictness.WARN)
+                .startMocking();
+        // Don't disable tethering provisioning unless requested.
+        doReturn(false).when(
+                () -> SystemProperties.getBoolean(
+                eq(EntitlementManager.DISABLE_PROVISIONING_SYSPROP_KEY), anyBoolean()));
+        doReturn(null).when(
+                () -> DeviceConfig.getProperty(eq(NAMESPACE_CONNECTIVITY), anyString()));
+
+        when(mResources.getStringArray(R.array.config_tether_dhcp_range))
+                .thenReturn(new String[0]);
+        when(mResources.getStringArray(R.array.config_tether_usb_regexs))
+                .thenReturn(new String[0]);
+        when(mResources.getStringArray(R.array.config_tether_wifi_regexs))
+                .thenReturn(new String[0]);
+        when(mResources.getStringArray(R.array.config_tether_bluetooth_regexs))
+                .thenReturn(new String[0]);
+        when(mResources.getIntArray(R.array.config_tether_upstream_types))
+                .thenReturn(new int[0]);
+        when(mResources.getBoolean(R.bool.config_tether_enable_legacy_dhcp_server)).thenReturn(
+                false);
+        when(mResources.getString(R.string.config_wifi_tether_enable)).thenReturn("");
+        when(mLog.forSubComponent(anyString())).thenReturn(mLog);
+
+        mMockContext = new MockContext(mContext);
+        mPermissionChangeCallback = spy(() -> { });
+        mEnMgr = new WrappedEntitlementManager(mMockContext, new Handler(mLooper.getLooper()), mLog,
+                mPermissionChangeCallback);
+        mEnMgr.setOnUiEntitlementFailedListener(mEntitlementFailedListener);
+        mConfig = new TetheringConfiguration(mMockContext, mLog, INVALID_SUBSCRIPTION_ID);
+        mEnMgr.setTetheringConfigurationFetcher(() -> {
+            return mConfig;
+        });
+    }
+
+    @After
+    public void tearDown() throws Exception {
+        mMockingSession.finishMocking();
+    }
+
+    private void setupForRequiredProvisioning() {
+        // Produce some acceptable looking provision app setting if requested.
+        when(mResources.getStringArray(R.array.config_mobile_hotspot_provision_app))
+                .thenReturn(PROVISIONING_APP_NAME);
+        when(mResources.getString(R.string.config_mobile_hotspot_provision_app_no_ui))
+                .thenReturn(PROVISIONING_NO_UI_APP_NAME);
+        when(mResources.getString(R.string.config_mobile_hotspot_provision_response)).thenReturn(
+                PROVISIONING_APP_RESPONSE);
+        // Act like the CarrierConfigManager is present and ready unless told otherwise.
+        when(mContext.getSystemService(Context.CARRIER_CONFIG_SERVICE))
+                .thenReturn(mCarrierConfigManager);
+        when(mCarrierConfigManager.getConfigForSubId(anyInt())).thenReturn(mCarrierConfig);
+        mCarrierConfig.putBoolean(CarrierConfigManager.KEY_REQUIRE_ENTITLEMENT_CHECKS_BOOL, true);
+        mCarrierConfig.putBoolean(CarrierConfigManager.KEY_CARRIER_CONFIG_APPLIED_BOOL, true);
+        mConfig = new TetheringConfiguration(mMockContext, mLog, INVALID_SUBSCRIPTION_ID);
+    }
+
+    @Test
+    public void canRequireProvisioning() {
+        setupForRequiredProvisioning();
+        assertTrue(mEnMgr.isTetherProvisioningRequired(mConfig));
+    }
+
+    @Test
+    public void toleratesCarrierConfigManagerMissing() {
+        setupForRequiredProvisioning();
+        when(mContext.getSystemService(Context.CARRIER_CONFIG_SERVICE))
+            .thenReturn(null);
+        mConfig = new TetheringConfiguration(mMockContext, mLog, INVALID_SUBSCRIPTION_ID);
+        // Couldn't get the CarrierConfigManager, but still had a declared provisioning app.
+        // Therefore provisioning still be required.
+        assertTrue(mEnMgr.isTetherProvisioningRequired(mConfig));
+    }
+
+    @Test
+    public void toleratesCarrierConfigMissing() {
+        setupForRequiredProvisioning();
+        when(mCarrierConfigManager.getConfig()).thenReturn(null);
+        mConfig = new TetheringConfiguration(mMockContext, mLog, INVALID_SUBSCRIPTION_ID);
+        // We still have a provisioning app configured, so still require provisioning.
+        assertTrue(mEnMgr.isTetherProvisioningRequired(mConfig));
+    }
+
+    @Test
+    public void toleratesCarrierConfigNotLoaded() {
+        setupForRequiredProvisioning();
+        mCarrierConfig.putBoolean(CarrierConfigManager.KEY_CARRIER_CONFIG_APPLIED_BOOL, false);
+        // We still have a provisioning app configured, so still require provisioning.
+        assertTrue(mEnMgr.isTetherProvisioningRequired(mConfig));
+    }
+
+    @Test
+    public void provisioningNotRequiredWhenAppNotFound() {
+        setupForRequiredProvisioning();
+        when(mResources.getStringArray(R.array.config_mobile_hotspot_provision_app))
+            .thenReturn(null);
+        mConfig = new TetheringConfiguration(mMockContext, mLog, INVALID_SUBSCRIPTION_ID);
+        assertFalse(mEnMgr.isTetherProvisioningRequired(mConfig));
+        when(mResources.getStringArray(R.array.config_mobile_hotspot_provision_app))
+            .thenReturn(new String[] {"malformedApp"});
+        mConfig = new TetheringConfiguration(mMockContext, mLog, INVALID_SUBSCRIPTION_ID);
+        assertFalse(mEnMgr.isTetherProvisioningRequired(mConfig));
+    }
+
+    @Test
+    public void testRequestLastEntitlementCacheValue() throws Exception {
+        // 1. Entitlement check is not required.
+        mEnMgr.fakeEntitlementResult = TETHER_ERROR_NO_ERROR;
+        ResultReceiver receiver = new ResultReceiver(null) {
+            @Override
+            protected void onReceiveResult(int resultCode, Bundle resultData) {
+                assertEquals(TETHER_ERROR_NO_ERROR, resultCode);
+            }
+        };
+        mEnMgr.requestLatestTetheringEntitlementResult(TETHERING_WIFI, receiver, true);
+        mLooper.dispatchAll();
+        assertEquals(0, mEnMgr.uiProvisionCount);
+        mEnMgr.reset();
+
+        setupForRequiredProvisioning();
+        // 2. No cache value and don't need to run entitlement check.
+        receiver = new ResultReceiver(null) {
+            @Override
+            protected void onReceiveResult(int resultCode, Bundle resultData) {
+                assertEquals(TETHER_ERROR_ENTITLEMENT_UNKNOWN, resultCode);
+            }
+        };
+        mEnMgr.requestLatestTetheringEntitlementResult(TETHERING_WIFI, receiver, false);
+        mLooper.dispatchAll();
+        assertEquals(0, mEnMgr.uiProvisionCount);
+        mEnMgr.reset();
+        // 3. No cache value and ui entitlement check is needed.
+        mEnMgr.fakeEntitlementResult = TETHER_ERROR_PROVISIONING_FAILED;
+        receiver = new ResultReceiver(null) {
+            @Override
+            protected void onReceiveResult(int resultCode, Bundle resultData) {
+                assertEquals(TETHER_ERROR_PROVISIONING_FAILED, resultCode);
+            }
+        };
+        mEnMgr.requestLatestTetheringEntitlementResult(TETHERING_WIFI, receiver, true);
+        mLooper.dispatchAll();
+        assertEquals(1, mEnMgr.uiProvisionCount);
+        mEnMgr.reset();
+        // 4. Cache value is TETHER_ERROR_PROVISIONING_FAILED and don't need to run entitlement
+        // check.
+        mEnMgr.fakeEntitlementResult = TETHER_ERROR_NO_ERROR;
+        receiver = new ResultReceiver(null) {
+            @Override
+            protected void onReceiveResult(int resultCode, Bundle resultData) {
+                assertEquals(TETHER_ERROR_PROVISIONING_FAILED, resultCode);
+            }
+        };
+        mEnMgr.requestLatestTetheringEntitlementResult(TETHERING_WIFI, receiver, false);
+        mLooper.dispatchAll();
+        assertEquals(0, mEnMgr.uiProvisionCount);
+        mEnMgr.reset();
+        // 5. Cache value is TETHER_ERROR_PROVISIONING_FAILED and ui entitlement check is needed.
+        mEnMgr.fakeEntitlementResult = TETHER_ERROR_NO_ERROR;
+        receiver = new ResultReceiver(null) {
+            @Override
+            protected void onReceiveResult(int resultCode, Bundle resultData) {
+                assertEquals(TETHER_ERROR_NO_ERROR, resultCode);
+            }
+        };
+        mEnMgr.requestLatestTetheringEntitlementResult(TETHERING_WIFI, receiver, true);
+        mLooper.dispatchAll();
+        assertEquals(1, mEnMgr.uiProvisionCount);
+        mEnMgr.reset();
+        // 6. Cache value is TETHER_ERROR_NO_ERROR.
+        mEnMgr.fakeEntitlementResult = TETHER_ERROR_NO_ERROR;
+        receiver = new ResultReceiver(null) {
+            @Override
+            protected void onReceiveResult(int resultCode, Bundle resultData) {
+                assertEquals(TETHER_ERROR_NO_ERROR, resultCode);
+            }
+        };
+        mEnMgr.requestLatestTetheringEntitlementResult(TETHERING_WIFI, receiver, true);
+        mLooper.dispatchAll();
+        assertEquals(0, mEnMgr.uiProvisionCount);
+        mEnMgr.reset();
+        // 7. Test get value for other downstream type.
+        receiver = new ResultReceiver(null) {
+            @Override
+            protected void onReceiveResult(int resultCode, Bundle resultData) {
+                assertEquals(TETHER_ERROR_ENTITLEMENT_UNKNOWN, resultCode);
+            }
+        };
+        mEnMgr.requestLatestTetheringEntitlementResult(TETHERING_USB, receiver, false);
+        mLooper.dispatchAll();
+        assertEquals(0, mEnMgr.uiProvisionCount);
+        mEnMgr.reset();
+        // 8. Test get value for invalid downstream type.
+        mEnMgr.fakeEntitlementResult = TETHER_ERROR_NO_ERROR;
+        receiver = new ResultReceiver(null) {
+            @Override
+            protected void onReceiveResult(int resultCode, Bundle resultData) {
+                assertEquals(TETHER_ERROR_ENTITLEMENT_UNKNOWN, resultCode);
+            }
+        };
+        mEnMgr.requestLatestTetheringEntitlementResult(TETHERING_WIFI_P2P, receiver, true);
+        mLooper.dispatchAll();
+        assertEquals(0, mEnMgr.uiProvisionCount);
+        mEnMgr.reset();
+    }
+
+    private void assertPermissionChangeCallback(InOrder inOrder) {
+        inOrder.verify(mPermissionChangeCallback, times(1)).run();
+    }
+
+    private void assertNoPermissionChange(InOrder inOrder) {
+        inOrder.verifyNoMoreInteractions();
+    }
+
+    @Test
+    public void verifyPermissionResult() {
+        final InOrder inOrder = inOrder(mPermissionChangeCallback);
+        setupForRequiredProvisioning();
+        mEnMgr.notifyUpstream(true);
+        mEnMgr.fakeEntitlementResult = TETHER_ERROR_PROVISIONING_FAILED;
+        mEnMgr.startProvisioningIfNeeded(TETHERING_WIFI, true);
+        mLooper.dispatchAll();
+        // Permitted: true -> false
+        assertPermissionChangeCallback(inOrder);
+        assertFalse(mEnMgr.isCellularUpstreamPermitted());
+
+        mEnMgr.stopProvisioningIfNeeded(TETHERING_WIFI);
+        mLooper.dispatchAll();
+        // Permitted: false -> false
+        assertNoPermissionChange(inOrder);
+
+        mEnMgr.fakeEntitlementResult = TETHER_ERROR_NO_ERROR;
+        mEnMgr.startProvisioningIfNeeded(TETHERING_WIFI, true);
+        mLooper.dispatchAll();
+        // Permitted: false -> true
+        assertPermissionChangeCallback(inOrder);
+        assertTrue(mEnMgr.isCellularUpstreamPermitted());
+    }
+
+    @Test
+    public void verifyPermissionIfAllNotApproved() {
+        final InOrder inOrder = inOrder(mPermissionChangeCallback);
+        setupForRequiredProvisioning();
+        mEnMgr.notifyUpstream(true);
+        mEnMgr.fakeEntitlementResult = TETHER_ERROR_PROVISIONING_FAILED;
+        mEnMgr.startProvisioningIfNeeded(TETHERING_WIFI, true);
+        mLooper.dispatchAll();
+        // Permitted: true -> false
+        assertPermissionChangeCallback(inOrder);
+        assertFalse(mEnMgr.isCellularUpstreamPermitted());
+
+        mEnMgr.fakeEntitlementResult = TETHER_ERROR_PROVISIONING_FAILED;
+        mEnMgr.startProvisioningIfNeeded(TETHERING_USB, true);
+        mLooper.dispatchAll();
+        // Permitted: false -> false
+        assertNoPermissionChange(inOrder);
+        assertFalse(mEnMgr.isCellularUpstreamPermitted());
+
+        mEnMgr.fakeEntitlementResult = TETHER_ERROR_PROVISIONING_FAILED;
+        mEnMgr.startProvisioningIfNeeded(TETHERING_BLUETOOTH, true);
+        mLooper.dispatchAll();
+        // Permitted: false -> false
+        assertNoPermissionChange(inOrder);
+        assertFalse(mEnMgr.isCellularUpstreamPermitted());
+    }
+
+    @Test
+    public void verifyPermissionIfAnyApproved() {
+        final InOrder inOrder = inOrder(mPermissionChangeCallback);
+        setupForRequiredProvisioning();
+        mEnMgr.notifyUpstream(true);
+        mEnMgr.fakeEntitlementResult = TETHER_ERROR_NO_ERROR;
+        mEnMgr.startProvisioningIfNeeded(TETHERING_WIFI, true);
+        mLooper.dispatchAll();
+        // Permitted: true -> true
+        assertNoPermissionChange(inOrder);
+        assertTrue(mEnMgr.isCellularUpstreamPermitted());
+
+        mEnMgr.fakeEntitlementResult = TETHER_ERROR_PROVISIONING_FAILED;
+        mEnMgr.startProvisioningIfNeeded(TETHERING_USB, true);
+        mLooper.dispatchAll();
+        // Permitted: true -> true
+        assertNoPermissionChange(inOrder);
+        assertTrue(mEnMgr.isCellularUpstreamPermitted());
+
+        mEnMgr.stopProvisioningIfNeeded(TETHERING_WIFI);
+        mLooper.dispatchAll();
+        // Permitted: true -> false
+        assertPermissionChangeCallback(inOrder);
+        assertFalse(mEnMgr.isCellularUpstreamPermitted());
+    }
+
+    @Test
+    public void verifyPermissionWhenProvisioningNotStarted() {
+        final InOrder inOrder = inOrder(mPermissionChangeCallback);
+        assertTrue(mEnMgr.isCellularUpstreamPermitted());
+        assertNoPermissionChange(inOrder);
+        setupForRequiredProvisioning();
+        assertFalse(mEnMgr.isCellularUpstreamPermitted());
+        assertNoPermissionChange(inOrder);
+    }
+
+    @Test
+    public void testRunTetherProvisioning() {
+        final InOrder inOrder = inOrder(mPermissionChangeCallback);
+        setupForRequiredProvisioning();
+        // 1. start ui provisioning, upstream is mobile
+        mEnMgr.fakeEntitlementResult = TETHER_ERROR_NO_ERROR;
+        mEnMgr.notifyUpstream(true);
+        mLooper.dispatchAll();
+        mEnMgr.startProvisioningIfNeeded(TETHERING_USB, true);
+        mLooper.dispatchAll();
+        assertEquals(1, mEnMgr.uiProvisionCount);
+        assertEquals(0, mEnMgr.silentProvisionCount);
+        // Permitted: true -> true
+        assertNoPermissionChange(inOrder);
+        assertTrue(mEnMgr.isCellularUpstreamPermitted());
+        mEnMgr.reset();
+
+        // 2. start no-ui provisioning
+        mEnMgr.fakeEntitlementResult = TETHER_ERROR_NO_ERROR;
+        mEnMgr.startProvisioningIfNeeded(TETHERING_WIFI, false);
+        mLooper.dispatchAll();
+        assertEquals(0, mEnMgr.uiProvisionCount);
+        assertEquals(1, mEnMgr.silentProvisionCount);
+        // Permitted: true -> true
+        assertNoPermissionChange(inOrder);
+        assertTrue(mEnMgr.isCellularUpstreamPermitted());
+        mEnMgr.reset();
+
+        // 3. tear down mobile, then start ui provisioning
+        mEnMgr.notifyUpstream(false);
+        mLooper.dispatchAll();
+        mEnMgr.startProvisioningIfNeeded(TETHERING_BLUETOOTH, true);
+        mLooper.dispatchAll();
+        assertEquals(0, mEnMgr.uiProvisionCount);
+        assertEquals(0, mEnMgr.silentProvisionCount);
+        assertNoPermissionChange(inOrder);
+        mEnMgr.reset();
+
+        // 4. switch upstream back to mobile
+        mEnMgr.fakeEntitlementResult = TETHER_ERROR_NO_ERROR;
+        mEnMgr.notifyUpstream(true);
+        mLooper.dispatchAll();
+        assertEquals(1, mEnMgr.uiProvisionCount);
+        assertEquals(0, mEnMgr.silentProvisionCount);
+        // Permitted: true -> true
+        assertNoPermissionChange(inOrder);
+        assertTrue(mEnMgr.isCellularUpstreamPermitted());
+        mEnMgr.reset();
+
+        // 5. tear down mobile, then switch SIM
+        mEnMgr.notifyUpstream(false);
+        mLooper.dispatchAll();
+        mEnMgr.reevaluateSimCardProvisioning(mConfig);
+        assertEquals(0, mEnMgr.uiProvisionCount);
+        assertEquals(0, mEnMgr.silentProvisionCount);
+        assertNoPermissionChange(inOrder);
+        mEnMgr.reset();
+
+        // 6. switch upstream back to mobile again
+        mEnMgr.fakeEntitlementResult = TETHER_ERROR_PROVISIONING_FAILED;
+        mEnMgr.notifyUpstream(true);
+        mLooper.dispatchAll();
+        assertEquals(0, mEnMgr.uiProvisionCount);
+        assertEquals(3, mEnMgr.silentProvisionCount);
+        // Permitted: true -> false
+        assertPermissionChangeCallback(inOrder);
+        assertFalse(mEnMgr.isCellularUpstreamPermitted());
+        mEnMgr.reset();
+
+        // 7. start ui provisioning, upstream is mobile, downstream is ethernet
+        mEnMgr.fakeEntitlementResult = TETHER_ERROR_NO_ERROR;
+        mEnMgr.startProvisioningIfNeeded(TETHERING_ETHERNET, true);
+        mLooper.dispatchAll();
+        assertEquals(1, mEnMgr.uiProvisionCount);
+        assertEquals(0, mEnMgr.silentProvisionCount);
+        // Permitted: false -> true
+        assertPermissionChangeCallback(inOrder);
+        assertTrue(mEnMgr.isCellularUpstreamPermitted());
+        mEnMgr.reset();
+
+        // 8. downstream is invalid
+        mEnMgr.fakeEntitlementResult = TETHER_ERROR_NO_ERROR;
+        mEnMgr.startProvisioningIfNeeded(TETHERING_WIFI_P2P, true);
+        mLooper.dispatchAll();
+        assertEquals(0, mEnMgr.uiProvisionCount);
+        assertEquals(0, mEnMgr.silentProvisionCount);
+        assertNoPermissionChange(inOrder);
+        mEnMgr.reset();
+    }
+
+    @Test
+    public void testCallStopTetheringWhenUiProvisioningFail() {
+        setupForRequiredProvisioning();
+        verify(mEntitlementFailedListener, times(0)).onUiEntitlementFailed(TETHERING_WIFI);
+        mEnMgr.fakeEntitlementResult = TETHER_ERROR_PROVISIONING_FAILED;
+        mEnMgr.notifyUpstream(true);
+        mLooper.dispatchAll();
+        mEnMgr.startProvisioningIfNeeded(TETHERING_WIFI, true);
+        mLooper.dispatchAll();
+        assertEquals(1, mEnMgr.uiProvisionCount);
+        verify(mEntitlementFailedListener, times(1)).onUiEntitlementFailed(TETHERING_WIFI);
+    }
+
+    @Test
+    public void testsetExemptedDownstreamType() throws Exception {
+        setupForRequiredProvisioning();
+        // Cellular upstream is not permitted when no entitlement result.
+        assertFalse(mEnMgr.isCellularUpstreamPermitted());
+
+        // If there is exempted downstream and no other non-exempted downstreams, cellular is
+        // permitted.
+        mEnMgr.setExemptedDownstreamType(TETHERING_WIFI);
+        assertTrue(mEnMgr.isCellularUpstreamPermitted());
+
+        // If second downstream run entitlement check fail, cellular upstream is not permitted.
+        mEnMgr.fakeEntitlementResult = TETHER_ERROR_PROVISIONING_FAILED;
+        mEnMgr.notifyUpstream(true);
+        mLooper.dispatchAll();
+        mEnMgr.startProvisioningIfNeeded(TETHERING_USB, true);
+        mLooper.dispatchAll();
+        assertFalse(mEnMgr.isCellularUpstreamPermitted());
+
+        // When second downstream is down, exempted downstream can use cellular upstream.
+        assertEquals(1, mEnMgr.uiProvisionCount);
+        verify(mEntitlementFailedListener).onUiEntitlementFailed(TETHERING_USB);
+        mEnMgr.stopProvisioningIfNeeded(TETHERING_USB);
+        assertTrue(mEnMgr.isCellularUpstreamPermitted());
+
+        mEnMgr.stopProvisioningIfNeeded(TETHERING_WIFI);
+        assertFalse(mEnMgr.isCellularUpstreamPermitted());
+    }
+}
diff --git a/Tethering/tests/unit/src/com/android/networkstack/tethering/IPv6TetheringCoordinatorTest.java b/Tethering/tests/unit/src/com/android/networkstack/tethering/IPv6TetheringCoordinatorTest.java
new file mode 100644
index 0000000..f2b5314
--- /dev/null
+++ b/Tethering/tests/unit/src/com/android/networkstack/tethering/IPv6TetheringCoordinatorTest.java
@@ -0,0 +1,156 @@
+/*
+ * Copyright (C) 2020 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.android.networkstack.tethering;
+
+import static android.net.NetworkCapabilities.TRANSPORT_CELLULAR;
+import static android.net.RouteInfo.RTN_UNICAST;
+import static android.net.ip.IpServer.STATE_LOCAL_ONLY;
+import static android.net.ip.IpServer.STATE_TETHERED;
+
+import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertFalse;
+import static org.junit.Assert.assertNotEquals;
+import static org.junit.Assert.assertNotNull;
+import static org.mockito.ArgumentMatchers.anyString;
+import static org.mockito.ArgumentMatchers.eq;
+import static org.mockito.Mockito.mock;
+import static org.mockito.Mockito.reset;
+import static org.mockito.Mockito.verify;
+import static org.mockito.Mockito.verifyNoMoreInteractions;
+import static org.mockito.Mockito.when;
+
+import android.net.InetAddresses;
+import android.net.IpPrefix;
+import android.net.LinkAddress;
+import android.net.LinkProperties;
+import android.net.Network;
+import android.net.NetworkCapabilities;
+import android.net.RouteInfo;
+import android.net.ip.IpServer;
+import android.net.util.SharedLog;
+
+import androidx.test.filters.SmallTest;
+import androidx.test.runner.AndroidJUnit4;
+
+import org.junit.Before;
+import org.junit.Test;
+import org.junit.runner.RunWith;
+import org.mockito.ArgumentCaptor;
+import org.mockito.Mock;
+import org.mockito.MockitoAnnotations;
+
+import java.net.InetAddress;
+import java.util.ArrayList;
+import java.util.List;
+
+@RunWith(AndroidJUnit4.class)
+@SmallTest
+public class IPv6TetheringCoordinatorTest {
+    private static final String TEST_DNS_SERVER = "2001:4860:4860::8888";
+    private static final String TEST_INTERFACE = "test_rmnet0";
+    private static final String TEST_IPV6_ADDRESS = "2001:db8::1/64";
+    private static final String TEST_IPV4_ADDRESS = "192.168.100.1/24";
+
+    private IPv6TetheringCoordinator mIPv6TetheringCoordinator;
+    private ArrayList<IpServer> mNotifyList;
+
+    @Mock private SharedLog mSharedLog;
+
+    @Before
+    public void setUp() throws Exception {
+        MockitoAnnotations.initMocks(this);
+        when(mSharedLog.forSubComponent(anyString())).thenReturn(mSharedLog);
+        mNotifyList = new ArrayList<IpServer>();
+        mIPv6TetheringCoordinator = new IPv6TetheringCoordinator(mNotifyList, mSharedLog);
+    }
+
+    private UpstreamNetworkState createDualStackUpstream(final int transportType) {
+        final Network network = mock(Network.class);
+        final NetworkCapabilities netCap =
+                new NetworkCapabilities.Builder().addTransportType(transportType).build();
+        final InetAddress dns = InetAddresses.parseNumericAddress(TEST_DNS_SERVER);
+        final LinkProperties linkProp = new LinkProperties();
+        linkProp.setInterfaceName(TEST_INTERFACE);
+        linkProp.addLinkAddress(new LinkAddress(TEST_IPV6_ADDRESS));
+        linkProp.addLinkAddress(new LinkAddress(TEST_IPV4_ADDRESS));
+        linkProp.addRoute(new RouteInfo(new IpPrefix("::/0"), null, TEST_INTERFACE, RTN_UNICAST));
+        linkProp.addRoute(new RouteInfo(new IpPrefix("0.0.0.0/0"), null, TEST_INTERFACE,
+                    RTN_UNICAST));
+        linkProp.addDnsServer(dns);
+        return new UpstreamNetworkState(linkProp, netCap, network);
+    }
+
+    private void assertOnlyOneV6AddressAndNoV4(LinkProperties lp) {
+        assertEquals(lp.getInterfaceName(), TEST_INTERFACE);
+        assertFalse(lp.hasIpv4Address());
+        final List<LinkAddress> addresses = lp.getLinkAddresses();
+        assertEquals(addresses.size(), 1);
+        final LinkAddress v6Address = addresses.get(0);
+        assertEquals(v6Address, new LinkAddress(TEST_IPV6_ADDRESS));
+    }
+
+    @Test
+    public void testUpdateIpv6Upstream() throws Exception {
+        // 1. Add first IpServer.
+        final IpServer firstServer = mock(IpServer.class);
+        mNotifyList.add(firstServer);
+        mIPv6TetheringCoordinator.addActiveDownstream(firstServer, STATE_TETHERED);
+        verify(firstServer).sendMessage(IpServer.CMD_IPV6_TETHER_UPDATE, 0, 0, null);
+        verifyNoMoreInteractions(firstServer);
+
+        // 2. Add second IpServer and it would not have ipv6 tethering.
+        final IpServer secondServer = mock(IpServer.class);
+        mNotifyList.add(secondServer);
+        mIPv6TetheringCoordinator.addActiveDownstream(secondServer, STATE_LOCAL_ONLY);
+        verifyNoMoreInteractions(secondServer);
+        reset(firstServer, secondServer);
+
+        // 3. No upstream.
+        mIPv6TetheringCoordinator.updateUpstreamNetworkState(null);
+        verify(secondServer).sendMessage(IpServer.CMD_IPV6_TETHER_UPDATE, 0, 0, null);
+        reset(firstServer, secondServer);
+
+        // 4. Update ipv6 mobile upstream.
+        final UpstreamNetworkState mobileUpstream = createDualStackUpstream(TRANSPORT_CELLULAR);
+        final ArgumentCaptor<LinkProperties> lp = ArgumentCaptor.forClass(LinkProperties.class);
+        mIPv6TetheringCoordinator.updateUpstreamNetworkState(mobileUpstream);
+        verify(firstServer).sendMessage(eq(IpServer.CMD_IPV6_TETHER_UPDATE), eq(-1), eq(0),
+                lp.capture());
+        final LinkProperties v6OnlyLink = lp.getValue();
+        assertOnlyOneV6AddressAndNoV4(v6OnlyLink);
+        verifyNoMoreInteractions(firstServer);
+        verifyNoMoreInteractions(secondServer);
+        reset(firstServer, secondServer);
+
+        // 5. Remove first IpServer.
+        mNotifyList.remove(firstServer);
+        mIPv6TetheringCoordinator.removeActiveDownstream(firstServer);
+        verify(firstServer).sendMessage(IpServer.CMD_IPV6_TETHER_UPDATE, 0, 0, null);
+        verify(secondServer).sendMessage(eq(IpServer.CMD_IPV6_TETHER_UPDATE), eq(-1), eq(0),
+                lp.capture());
+        final LinkProperties localOnlyLink = lp.getValue();
+        assertNotNull(localOnlyLink);
+        assertNotEquals(localOnlyLink, v6OnlyLink);
+        reset(firstServer, secondServer);
+
+        // 6. Remove second IpServer.
+        mNotifyList.remove(secondServer);
+        mIPv6TetheringCoordinator.removeActiveDownstream(secondServer);
+        verifyNoMoreInteractions(firstServer);
+        verify(secondServer).sendMessage(IpServer.CMD_IPV6_TETHER_UPDATE, 0, 0, null);
+    }
+}
diff --git a/Tethering/tests/unit/src/com/android/networkstack/tethering/MockTetheringService.java b/Tethering/tests/unit/src/com/android/networkstack/tethering/MockTetheringService.java
new file mode 100644
index 0000000..071a290
--- /dev/null
+++ b/Tethering/tests/unit/src/com/android/networkstack/tethering/MockTetheringService.java
@@ -0,0 +1,72 @@
+/*
+ * Copyright (C) 2020 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package com.android.networkstack.tethering;
+
+import static android.Manifest.permission.WRITE_SETTINGS;
+import static android.content.pm.PackageManager.PERMISSION_GRANTED;
+
+import static org.mockito.Mockito.mock;
+
+import android.content.Context;
+import android.content.Intent;
+import android.net.ITetheringConnector;
+import android.os.Binder;
+import android.os.IBinder;
+
+import androidx.annotation.NonNull;
+import androidx.annotation.Nullable;
+
+public class MockTetheringService extends TetheringService {
+    private final Tethering mTethering = mock(Tethering.class);
+
+    @Override
+    public IBinder onBind(Intent intent) {
+        return new MockTetheringConnector(super.onBind(intent));
+    }
+
+    @Override
+    public Tethering makeTethering(TetheringDependencies deps) {
+        return mTethering;
+    }
+
+    @Override
+    boolean checkAndNoteWriteSettingsOperation(@NonNull Context context, int uid,
+            @NonNull String callingPackage, @Nullable String callingAttributionTag,
+            boolean throwException) {
+        // Test this does not verify the calling package / UID, as calling package could be shell
+        // and not match the UID.
+        return context.checkCallingOrSelfPermission(WRITE_SETTINGS) == PERMISSION_GRANTED;
+    }
+
+    public Tethering getTethering() {
+        return mTethering;
+    }
+
+    public class MockTetheringConnector extends Binder {
+        final IBinder mBase;
+        MockTetheringConnector(IBinder base) {
+            mBase = base;
+        }
+
+        public ITetheringConnector getTetheringConnector() {
+            return ITetheringConnector.Stub.asInterface(mBase);
+        }
+
+        public MockTetheringService getService() {
+            return MockTetheringService.this;
+        }
+    }
+}
diff --git a/Tethering/tests/unit/src/com/android/networkstack/tethering/OffloadControllerTest.java b/Tethering/tests/unit/src/com/android/networkstack/tethering/OffloadControllerTest.java
new file mode 100644
index 0000000..ce52ae2
--- /dev/null
+++ b/Tethering/tests/unit/src/com/android/networkstack/tethering/OffloadControllerTest.java
@@ -0,0 +1,827 @@
+/*
+ * Copyright (C) 2017 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.android.networkstack.tethering;
+
+import static android.net.NetworkStats.DEFAULT_NETWORK_NO;
+import static android.net.NetworkStats.METERED_NO;
+import static android.net.NetworkStats.ROAMING_NO;
+import static android.net.NetworkStats.SET_DEFAULT;
+import static android.net.NetworkStats.TAG_NONE;
+import static android.net.NetworkStats.UID_ALL;
+import static android.net.NetworkStats.UID_TETHERING;
+import static android.net.RouteInfo.RTN_UNICAST;
+import static android.provider.Settings.Global.TETHER_OFFLOAD_DISABLED;
+
+import static com.android.networkstack.tethering.OffloadController.StatsType.STATS_PER_IFACE;
+import static com.android.networkstack.tethering.OffloadController.StatsType.STATS_PER_UID;
+import static com.android.networkstack.tethering.OffloadHardwareInterface.ForwardedStats;
+import static com.android.networkstack.tethering.TetheringConfiguration.DEFAULT_TETHER_OFFLOAD_POLL_INTERVAL_MS;
+import static com.android.testutils.MiscAsserts.assertContainsAll;
+import static com.android.testutils.MiscAsserts.assertThrows;
+import static com.android.testutils.NetworkStatsUtilsKt.assertNetworkStatsEquals;
+
+import static junit.framework.Assert.assertNotNull;
+
+import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertTrue;
+import static org.mockito.Matchers.any;
+import static org.mockito.Matchers.anyLong;
+import static org.mockito.Matchers.anyObject;
+import static org.mockito.Matchers.anyString;
+import static org.mockito.Matchers.eq;
+import static org.mockito.Mockito.clearInvocations;
+import static org.mockito.Mockito.inOrder;
+import static org.mockito.Mockito.never;
+import static org.mockito.Mockito.reset;
+import static org.mockito.Mockito.times;
+import static org.mockito.Mockito.verify;
+import static org.mockito.Mockito.verifyNoMoreInteractions;
+import static org.mockito.Mockito.when;
+
+import android.annotation.NonNull;
+import android.app.usage.NetworkStatsManager;
+import android.content.Context;
+import android.content.pm.ApplicationInfo;
+import android.net.ITetheringStatsProvider;
+import android.net.IpPrefix;
+import android.net.LinkAddress;
+import android.net.LinkProperties;
+import android.net.NetworkStats;
+import android.net.NetworkStats.Entry;
+import android.net.RouteInfo;
+import android.net.netstats.provider.NetworkStatsProvider;
+import android.net.util.SharedLog;
+import android.os.Handler;
+import android.os.test.TestLooper;
+import android.provider.Settings;
+import android.provider.Settings.SettingNotFoundException;
+import android.test.mock.MockContentResolver;
+
+import androidx.test.filters.SmallTest;
+import androidx.test.runner.AndroidJUnit4;
+
+import com.android.internal.util.test.FakeSettingsProvider;
+import com.android.testutils.TestableNetworkStatsProviderCbBinder;
+
+import org.junit.After;
+import org.junit.Before;
+import org.junit.Test;
+import org.junit.runner.RunWith;
+import org.mockito.ArgumentCaptor;
+import org.mockito.InOrder;
+import org.mockito.Mock;
+import org.mockito.MockitoAnnotations;
+
+import java.net.InetAddress;
+import java.util.ArrayList;
+import java.util.HashSet;
+import java.util.Set;
+
+@RunWith(AndroidJUnit4.class)
+@SmallTest
+public class OffloadControllerTest {
+    private static final String RNDIS0 = "test_rndis0";
+    private static final String RMNET0 = "test_rmnet_data0";
+    private static final String WLAN0 = "test_wlan0";
+
+    private static final String IPV6_LINKLOCAL = "fe80::/64";
+    private static final String IPV6_DOC_PREFIX = "2001:db8::/64";
+    private static final String IPV6_DISCARD_PREFIX = "100::/64";
+    private static final String USB_PREFIX = "192.168.42.0/24";
+    private static final String WIFI_PREFIX = "192.168.43.0/24";
+    private static final long WAIT_FOR_IDLE_TIMEOUT = 2 * 1000;
+
+    @Mock private OffloadHardwareInterface mHardware;
+    @Mock private ApplicationInfo mApplicationInfo;
+    @Mock private Context mContext;
+    @Mock private NetworkStatsManager mStatsManager;
+    @Mock private TetheringConfiguration mTetherConfig;
+    // Late init since methods must be called by the thread that created this object.
+    private TestableNetworkStatsProviderCbBinder mTetherStatsProviderCb;
+    private OffloadController.OffloadTetheringStatsProvider mTetherStatsProvider;
+    private final ArgumentCaptor<ArrayList> mStringArrayCaptor =
+            ArgumentCaptor.forClass(ArrayList.class);
+    private final ArgumentCaptor<OffloadHardwareInterface.ControlCallback> mControlCallbackCaptor =
+            ArgumentCaptor.forClass(OffloadHardwareInterface.ControlCallback.class);
+    private MockContentResolver mContentResolver;
+    private final TestLooper mTestLooper = new TestLooper();
+    private OffloadController.Dependencies mDeps = new OffloadController.Dependencies() {
+        @Override
+        public TetheringConfiguration getTetherConfig() {
+            return mTetherConfig;
+        }
+    };
+
+    @Before public void setUp() {
+        MockitoAnnotations.initMocks(this);
+        when(mContext.getApplicationInfo()).thenReturn(mApplicationInfo);
+        when(mContext.getPackageName()).thenReturn("OffloadControllerTest");
+        mContentResolver = new MockContentResolver(mContext);
+        mContentResolver.addProvider(Settings.AUTHORITY, new FakeSettingsProvider());
+        when(mContext.getContentResolver()).thenReturn(mContentResolver);
+        FakeSettingsProvider.clearSettingsProvider();
+        when(mTetherConfig.getOffloadPollInterval()).thenReturn(-1); // Disabled.
+    }
+
+    @After public void tearDown() throws Exception {
+        FakeSettingsProvider.clearSettingsProvider();
+    }
+
+    private void setupFunctioningHardwareInterface() {
+        when(mHardware.initOffloadConfig()).thenReturn(true);
+        when(mHardware.initOffloadControl(mControlCallbackCaptor.capture()))
+                .thenReturn(true);
+        when(mHardware.setUpstreamParameters(anyString(), any(), any(), any())).thenReturn(true);
+        when(mHardware.getForwardedStats(any())).thenReturn(new ForwardedStats());
+        when(mHardware.setDataLimit(anyString(), anyLong())).thenReturn(true);
+    }
+
+    private void enableOffload() {
+        Settings.Global.putInt(mContentResolver, TETHER_OFFLOAD_DISABLED, 0);
+    }
+
+    private void setOffloadPollInterval(int interval) {
+        when(mTetherConfig.getOffloadPollInterval()).thenReturn(interval);
+    }
+
+    private void waitForIdle() {
+        mTestLooper.dispatchAll();
+    }
+
+    private OffloadController makeOffloadController() throws Exception {
+        OffloadController offload = new OffloadController(new Handler(mTestLooper.getLooper()),
+                mHardware, mContentResolver, mStatsManager, new SharedLog("test"), mDeps);
+        final ArgumentCaptor<OffloadController.OffloadTetheringStatsProvider>
+                tetherStatsProviderCaptor =
+                ArgumentCaptor.forClass(OffloadController.OffloadTetheringStatsProvider.class);
+        verify(mStatsManager).registerNetworkStatsProvider(anyString(),
+                tetherStatsProviderCaptor.capture());
+        mTetherStatsProvider = tetherStatsProviderCaptor.getValue();
+        assertNotNull(mTetherStatsProvider);
+        mTetherStatsProviderCb = new TestableNetworkStatsProviderCbBinder();
+        mTetherStatsProvider.setProviderCallbackBinder(mTetherStatsProviderCb);
+        return offload;
+    }
+
+    @Test
+    public void testNoSettingsValueDefaultDisabledDoesNotStart() throws Exception {
+        setupFunctioningHardwareInterface();
+        when(mHardware.getDefaultTetherOffloadDisabled()).thenReturn(1);
+        assertThrows(SettingNotFoundException.class, () ->
+                Settings.Global.getInt(mContentResolver, TETHER_OFFLOAD_DISABLED));
+
+        final OffloadController offload = makeOffloadController();
+        offload.start();
+
+        final InOrder inOrder = inOrder(mHardware);
+        inOrder.verify(mHardware, times(1)).getDefaultTetherOffloadDisabled();
+        inOrder.verify(mHardware, never()).initOffloadConfig();
+        inOrder.verify(mHardware, never()).initOffloadControl(
+                any(OffloadHardwareInterface.ControlCallback.class));
+        inOrder.verifyNoMoreInteractions();
+    }
+
+    @Test
+    public void testNoSettingsValueDefaultEnabledDoesStart() throws Exception {
+        setupFunctioningHardwareInterface();
+        when(mHardware.getDefaultTetherOffloadDisabled()).thenReturn(0);
+        assertThrows(SettingNotFoundException.class, () ->
+                Settings.Global.getInt(mContentResolver, TETHER_OFFLOAD_DISABLED));
+
+        final OffloadController offload = makeOffloadController();
+        offload.start();
+
+        final InOrder inOrder = inOrder(mHardware);
+        inOrder.verify(mHardware, times(1)).getDefaultTetherOffloadDisabled();
+        inOrder.verify(mHardware, times(1)).initOffloadConfig();
+        inOrder.verify(mHardware, times(1)).initOffloadControl(
+                any(OffloadHardwareInterface.ControlCallback.class));
+        inOrder.verifyNoMoreInteractions();
+    }
+
+    @Test
+    public void testSettingsAllowsStart() throws Exception {
+        setupFunctioningHardwareInterface();
+        Settings.Global.putInt(mContentResolver, TETHER_OFFLOAD_DISABLED, 0);
+
+        final OffloadController offload = makeOffloadController();
+        offload.start();
+
+        final InOrder inOrder = inOrder(mHardware);
+        inOrder.verify(mHardware, times(1)).getDefaultTetherOffloadDisabled();
+        inOrder.verify(mHardware, times(1)).initOffloadConfig();
+        inOrder.verify(mHardware, times(1)).initOffloadControl(
+                any(OffloadHardwareInterface.ControlCallback.class));
+        inOrder.verifyNoMoreInteractions();
+    }
+
+    @Test
+    public void testSettingsDisablesStart() throws Exception {
+        setupFunctioningHardwareInterface();
+        Settings.Global.putInt(mContentResolver, TETHER_OFFLOAD_DISABLED, 1);
+
+        final OffloadController offload = makeOffloadController();
+        offload.start();
+
+        final InOrder inOrder = inOrder(mHardware);
+        inOrder.verify(mHardware, times(1)).getDefaultTetherOffloadDisabled();
+        inOrder.verify(mHardware, never()).initOffloadConfig();
+        inOrder.verify(mHardware, never()).initOffloadControl(anyObject());
+        inOrder.verifyNoMoreInteractions();
+    }
+
+    @Test
+    public void testSetUpstreamLinkPropertiesWorking() throws Exception {
+        setupFunctioningHardwareInterface();
+        enableOffload();
+
+        final OffloadController offload = makeOffloadController();
+        offload.start();
+
+        final InOrder inOrder = inOrder(mHardware);
+        inOrder.verify(mHardware, times(1)).getDefaultTetherOffloadDisabled();
+        inOrder.verify(mHardware, times(1)).initOffloadConfig();
+        inOrder.verify(mHardware, times(1)).initOffloadControl(
+                any(OffloadHardwareInterface.ControlCallback.class));
+        inOrder.verifyNoMoreInteractions();
+
+        // In reality, the UpstreamNetworkMonitor would have passed down to us
+        // a covering set of local prefixes representing a minimum essential
+        // set plus all the prefixes on networks with network agents.
+        //
+        // We simulate that there, and then add upstream elements one by one
+        // and watch what happens.
+        final Set<IpPrefix> minimumLocalPrefixes = new HashSet<>();
+        for (String s : new String[]{
+                "127.0.0.0/8", "192.0.2.0/24", "fe80::/64", "2001:db8::/64"}) {
+            minimumLocalPrefixes.add(new IpPrefix(s));
+        }
+        offload.setLocalPrefixes(minimumLocalPrefixes);
+        inOrder.verify(mHardware, times(1)).setLocalPrefixes(mStringArrayCaptor.capture());
+        ArrayList<String> localPrefixes = mStringArrayCaptor.getValue();
+        assertEquals(4, localPrefixes.size());
+        assertContainsAll(localPrefixes,
+                "127.0.0.0/8", "192.0.2.0/24", "fe80::/64", "2001:db8::/64");
+        inOrder.verifyNoMoreInteractions();
+
+        offload.setUpstreamLinkProperties(null);
+        // No change in local addresses means no call to setLocalPrefixes().
+        inOrder.verify(mHardware, never()).setLocalPrefixes(mStringArrayCaptor.capture());
+        // This LinkProperties value does not differ from the default upstream.
+        // There should be no extraneous call to setUpstreamParameters().
+        inOrder.verify(mHardware, never()).setUpstreamParameters(
+                anyObject(), anyObject(), anyObject(), anyObject());
+        inOrder.verifyNoMoreInteractions();
+
+        final LinkProperties lp = new LinkProperties();
+
+        final String testIfName = "rmnet_data17";
+        lp.setInterfaceName(testIfName);
+        offload.setUpstreamLinkProperties(lp);
+        // No change in local addresses means no call to setLocalPrefixes().
+        inOrder.verify(mHardware, never()).setLocalPrefixes(mStringArrayCaptor.capture());
+        inOrder.verify(mHardware, times(1)).setUpstreamParameters(
+                eq(testIfName), eq(null), eq(null), eq(null));
+        inOrder.verify(mHardware, times(1)).setDataLimit(eq(testIfName), eq(Long.MAX_VALUE));
+        inOrder.verifyNoMoreInteractions();
+
+        final String ipv4Addr = "192.0.2.5";
+        final String linkAddr = ipv4Addr + "/24";
+        lp.addLinkAddress(new LinkAddress(linkAddr));
+        lp.addRoute(new RouteInfo(new IpPrefix("192.0.2.0/24"), null, null, RTN_UNICAST));
+        offload.setUpstreamLinkProperties(lp);
+        // IPv4 prefixes and addresses on the upstream are simply left as whole
+        // prefixes (already passed in from UpstreamNetworkMonitor code). If a
+        // tethering client sends traffic to the IPv4 default router or other
+        // clients on the upstream this will not be hardware-forwarded, and that
+        // should be fine for now. Ergo: no change in local addresses, no call
+        // to setLocalPrefixes().
+        inOrder.verify(mHardware, never()).setLocalPrefixes(mStringArrayCaptor.capture());
+        inOrder.verify(mHardware, times(1)).setUpstreamParameters(
+                eq(testIfName), eq(ipv4Addr), eq(null), eq(null));
+        inOrder.verify(mHardware, times(1)).getForwardedStats(eq(testIfName));
+        inOrder.verify(mHardware, times(1)).setDataLimit(eq(testIfName), eq(Long.MAX_VALUE));
+        inOrder.verifyNoMoreInteractions();
+
+        final String ipv4Gateway = "192.0.2.1";
+        lp.addRoute(new RouteInfo(null, InetAddress.getByName(ipv4Gateway), null, RTN_UNICAST));
+        offload.setUpstreamLinkProperties(lp);
+        // No change in local addresses means no call to setLocalPrefixes().
+        inOrder.verify(mHardware, never()).setLocalPrefixes(mStringArrayCaptor.capture());
+        inOrder.verify(mHardware, times(1)).setUpstreamParameters(
+                eq(testIfName), eq(ipv4Addr), eq(ipv4Gateway), eq(null));
+        inOrder.verify(mHardware, times(1)).getForwardedStats(eq(testIfName));
+        inOrder.verify(mHardware, times(1)).setDataLimit(eq(testIfName), eq(Long.MAX_VALUE));
+        inOrder.verifyNoMoreInteractions();
+
+        final String ipv6Gw1 = "fe80::cafe";
+        lp.addRoute(new RouteInfo(null, InetAddress.getByName(ipv6Gw1), null, RTN_UNICAST));
+        offload.setUpstreamLinkProperties(lp);
+        // No change in local addresses means no call to setLocalPrefixes().
+        inOrder.verify(mHardware, never()).setLocalPrefixes(mStringArrayCaptor.capture());
+        inOrder.verify(mHardware, times(1)).setUpstreamParameters(
+                eq(testIfName), eq(ipv4Addr), eq(ipv4Gateway), mStringArrayCaptor.capture());
+        inOrder.verify(mHardware, times(1)).getForwardedStats(eq(testIfName));
+        ArrayList<String> v6gws = mStringArrayCaptor.getValue();
+        assertEquals(1, v6gws.size());
+        assertTrue(v6gws.contains(ipv6Gw1));
+        inOrder.verify(mHardware, times(1)).setDataLimit(eq(testIfName), eq(Long.MAX_VALUE));
+        inOrder.verifyNoMoreInteractions();
+
+        final String ipv6Gw2 = "fe80::d00d";
+        lp.addRoute(new RouteInfo(null, InetAddress.getByName(ipv6Gw2), null, RTN_UNICAST));
+        offload.setUpstreamLinkProperties(lp);
+        // No change in local addresses means no call to setLocalPrefixes().
+        inOrder.verify(mHardware, never()).setLocalPrefixes(mStringArrayCaptor.capture());
+        inOrder.verify(mHardware, times(1)).setUpstreamParameters(
+                eq(testIfName), eq(ipv4Addr), eq(ipv4Gateway), mStringArrayCaptor.capture());
+        inOrder.verify(mHardware, times(1)).getForwardedStats(eq(testIfName));
+        v6gws = mStringArrayCaptor.getValue();
+        assertEquals(2, v6gws.size());
+        assertTrue(v6gws.contains(ipv6Gw1));
+        assertTrue(v6gws.contains(ipv6Gw2));
+        inOrder.verify(mHardware, times(1)).setDataLimit(eq(testIfName), eq(Long.MAX_VALUE));
+        inOrder.verifyNoMoreInteractions();
+
+        final LinkProperties stacked = new LinkProperties();
+        stacked.setInterfaceName("stacked");
+        stacked.addLinkAddress(new LinkAddress("192.0.2.129/25"));
+        stacked.addRoute(new RouteInfo(null, InetAddress.getByName("192.0.2.254"), null,
+                RTN_UNICAST));
+        stacked.addRoute(new RouteInfo(null, InetAddress.getByName("fe80::bad:f00"), null,
+                RTN_UNICAST));
+        assertTrue(lp.addStackedLink(stacked));
+        offload.setUpstreamLinkProperties(lp);
+        // No change in local addresses means no call to setLocalPrefixes().
+        inOrder.verify(mHardware, never()).setLocalPrefixes(mStringArrayCaptor.capture());
+        inOrder.verify(mHardware, times(1)).setUpstreamParameters(
+                eq(testIfName), eq(ipv4Addr), eq(ipv4Gateway), mStringArrayCaptor.capture());
+        inOrder.verify(mHardware, times(1)).getForwardedStats(eq(testIfName));
+        v6gws = mStringArrayCaptor.getValue();
+        assertEquals(2, v6gws.size());
+        assertTrue(v6gws.contains(ipv6Gw1));
+        assertTrue(v6gws.contains(ipv6Gw2));
+        inOrder.verify(mHardware, times(1)).setDataLimit(eq(testIfName), eq(Long.MAX_VALUE));
+        inOrder.verifyNoMoreInteractions();
+
+        // Add in some IPv6 upstream info. When there is a tethered downstream
+        // making use of the IPv6 prefix we would expect to see the /64 route
+        // removed from "local prefixes" and /128s added for the upstream IPv6
+        // addresses.  This is not yet implemented, and for now we simply
+        // expect to see these /128s.
+        lp.addRoute(new RouteInfo(new IpPrefix("2001:db8::/64"), null, null, RTN_UNICAST));
+        // "2001:db8::/64" plus "assigned" ASCII in hex
+        lp.addLinkAddress(new LinkAddress("2001:db8::6173:7369:676e:6564/64"));
+        // "2001:db8::/64" plus "random" ASCII in hex
+        lp.addLinkAddress(new LinkAddress("2001:db8::7261:6e64:6f6d/64"));
+        offload.setUpstreamLinkProperties(lp);
+        inOrder.verify(mHardware, times(1)).setLocalPrefixes(mStringArrayCaptor.capture());
+        localPrefixes = mStringArrayCaptor.getValue();
+        assertEquals(6, localPrefixes.size());
+        assertContainsAll(localPrefixes,
+                "127.0.0.0/8", "192.0.2.0/24", "fe80::/64", "2001:db8::/64",
+                "2001:db8::6173:7369:676e:6564/128", "2001:db8::7261:6e64:6f6d/128");
+        // The relevant parts of the LinkProperties have not changed, but at the
+        // moment we do not de-dup upstream LinkProperties this carefully.
+        inOrder.verify(mHardware, times(1)).setUpstreamParameters(
+                eq(testIfName), eq(ipv4Addr), eq(ipv4Gateway), mStringArrayCaptor.capture());
+        v6gws = mStringArrayCaptor.getValue();
+        assertEquals(2, v6gws.size());
+        assertTrue(v6gws.contains(ipv6Gw1));
+        assertTrue(v6gws.contains(ipv6Gw2));
+        inOrder.verify(mHardware, times(1)).getForwardedStats(eq(testIfName));
+        inOrder.verify(mHardware, times(1)).setDataLimit(eq(testIfName), eq(Long.MAX_VALUE));
+        inOrder.verifyNoMoreInteractions();
+
+        // Completely identical LinkProperties updates are de-duped.
+        offload.setUpstreamLinkProperties(lp);
+        // This LinkProperties value does not differ from the default upstream.
+        // There should be no extraneous call to setUpstreamParameters().
+        inOrder.verify(mHardware, never()).setUpstreamParameters(
+                anyObject(), anyObject(), anyObject(), anyObject());
+        inOrder.verifyNoMoreInteractions();
+    }
+
+    private static @NonNull Entry buildTestEntry(@NonNull OffloadController.StatsType how,
+            @NonNull String iface, long rxBytes, long txBytes) {
+        return new Entry(iface, how == STATS_PER_IFACE ? UID_ALL : UID_TETHERING, SET_DEFAULT,
+                TAG_NONE, METERED_NO, ROAMING_NO, DEFAULT_NETWORK_NO, rxBytes, 0L,
+                txBytes, 0L, 0L);
+    }
+
+    @Test
+    public void testGetForwardedStats() throws Exception {
+        setupFunctioningHardwareInterface();
+        enableOffload();
+
+        final OffloadController offload = makeOffloadController();
+        offload.start();
+
+        final String ethernetIface = "eth1";
+        final String mobileIface = "rmnet_data0";
+
+        when(mHardware.getForwardedStats(eq(ethernetIface))).thenReturn(
+                new ForwardedStats(12345, 54321));
+        when(mHardware.getForwardedStats(eq(mobileIface))).thenReturn(
+                new ForwardedStats(999, 99999));
+
+        InOrder inOrder = inOrder(mHardware);
+
+        final LinkProperties lp = new LinkProperties();
+        lp.setInterfaceName(ethernetIface);
+        offload.setUpstreamLinkProperties(lp);
+        // Previous upstream was null, so no stats are fetched.
+        inOrder.verify(mHardware, never()).getForwardedStats(any());
+
+        lp.setInterfaceName(mobileIface);
+        offload.setUpstreamLinkProperties(lp);
+        // Expect that we fetch stats from the previous upstream.
+        inOrder.verify(mHardware, times(1)).getForwardedStats(eq(ethernetIface));
+
+        lp.setInterfaceName(ethernetIface);
+        offload.setUpstreamLinkProperties(lp);
+        // Expect that we fetch stats from the previous upstream.
+        inOrder.verify(mHardware, times(1)).getForwardedStats(eq(mobileIface));
+
+        // Verify that the fetched stats are stored.
+        final NetworkStats ifaceStats = mTetherStatsProvider.getTetherStats(STATS_PER_IFACE);
+        final NetworkStats uidStats = mTetherStatsProvider.getTetherStats(STATS_PER_UID);
+        final NetworkStats expectedIfaceStats = new NetworkStats(0L, 2)
+                .addEntry(buildTestEntry(STATS_PER_IFACE, mobileIface, 999, 99999))
+                .addEntry(buildTestEntry(STATS_PER_IFACE, ethernetIface, 12345, 54321));
+
+        final NetworkStats expectedUidStats = new NetworkStats(0L, 2)
+                .addEntry(buildTestEntry(STATS_PER_UID, mobileIface, 999, 99999))
+                .addEntry(buildTestEntry(STATS_PER_UID, ethernetIface, 12345, 54321));
+
+        assertNetworkStatsEquals(expectedIfaceStats, ifaceStats);
+        assertNetworkStatsEquals(expectedUidStats, uidStats);
+
+        // Force pushing stats update to verify the stats reported.
+        mTetherStatsProvider.pushTetherStats();
+        mTetherStatsProviderCb.expectNotifyStatsUpdated(expectedIfaceStats, expectedUidStats);
+
+        when(mHardware.getForwardedStats(eq(ethernetIface))).thenReturn(
+                new ForwardedStats(100000, 100000));
+        offload.setUpstreamLinkProperties(null);
+        // Expect that we first clear the HAL's upstream parameters.
+        inOrder.verify(mHardware, times(1)).setUpstreamParameters(
+                eq(""), eq("0.0.0.0"), eq("0.0.0.0"), eq(null));
+        // Expect that we fetch stats from the previous upstream.
+        inOrder.verify(mHardware, times(1)).getForwardedStats(eq(ethernetIface));
+
+        // There is no current upstream, so no stats are fetched.
+        inOrder.verify(mHardware, never()).getForwardedStats(any());
+        inOrder.verifyNoMoreInteractions();
+
+        // Verify that the stored stats is accumulated.
+        final NetworkStats ifaceStatsAccu = mTetherStatsProvider.getTetherStats(STATS_PER_IFACE);
+        final NetworkStats uidStatsAccu = mTetherStatsProvider.getTetherStats(STATS_PER_UID);
+        final NetworkStats expectedIfaceStatsAccu = new NetworkStats(0L, 2)
+                .addEntry(buildTestEntry(STATS_PER_IFACE, mobileIface, 999, 99999))
+                .addEntry(buildTestEntry(STATS_PER_IFACE, ethernetIface, 112345, 154321));
+
+        final NetworkStats expectedUidStatsAccu = new NetworkStats(0L, 2)
+                .addEntry(buildTestEntry(STATS_PER_UID, mobileIface, 999, 99999))
+                .addEntry(buildTestEntry(STATS_PER_UID, ethernetIface, 112345, 154321));
+
+        assertNetworkStatsEquals(expectedIfaceStatsAccu, ifaceStatsAccu);
+        assertNetworkStatsEquals(expectedUidStatsAccu, uidStatsAccu);
+
+        // Verify that only diff of stats is reported.
+        mTetherStatsProvider.pushTetherStats();
+        final NetworkStats expectedIfaceStatsDiff = new NetworkStats(0L, 2)
+                .addEntry(buildTestEntry(STATS_PER_IFACE, mobileIface, 0, 0))
+                .addEntry(buildTestEntry(STATS_PER_IFACE, ethernetIface, 100000, 100000));
+
+        final NetworkStats expectedUidStatsDiff = new NetworkStats(0L, 2)
+                .addEntry(buildTestEntry(STATS_PER_UID, mobileIface, 0, 0))
+                .addEntry(buildTestEntry(STATS_PER_UID, ethernetIface, 100000, 100000));
+        mTetherStatsProviderCb.expectNotifyStatsUpdated(expectedIfaceStatsDiff,
+                expectedUidStatsDiff);
+    }
+
+    @Test
+    public void testSetInterfaceQuota() throws Exception {
+        setupFunctioningHardwareInterface();
+        enableOffload();
+
+        final OffloadController offload = makeOffloadController();
+        offload.start();
+
+        final String ethernetIface = "eth1";
+        final String mobileIface = "rmnet_data0";
+        final long ethernetLimit = 12345;
+        final long mobileLimit = 12345678;
+
+        final LinkProperties lp = new LinkProperties();
+        lp.setInterfaceName(ethernetIface);
+        offload.setUpstreamLinkProperties(lp);
+
+        final InOrder inOrder = inOrder(mHardware);
+        when(mHardware.setUpstreamParameters(any(), any(), any(), any())).thenReturn(true);
+        when(mHardware.setDataLimit(anyString(), anyLong())).thenReturn(true);
+
+        // Applying an interface quota to the current upstream immediately sends it to the hardware.
+        mTetherStatsProvider.onSetLimit(ethernetIface, ethernetLimit);
+        waitForIdle();
+        inOrder.verify(mHardware).setDataLimit(ethernetIface, ethernetLimit);
+        inOrder.verifyNoMoreInteractions();
+
+        // Applying an interface quota to another upstream does not take any immediate action.
+        mTetherStatsProvider.onSetLimit(mobileIface, mobileLimit);
+        waitForIdle();
+        inOrder.verify(mHardware, never()).setDataLimit(anyString(), anyLong());
+
+        // Switching to that upstream causes the quota to be applied if the parameters were applied
+        // correctly.
+        lp.setInterfaceName(mobileIface);
+        offload.setUpstreamLinkProperties(lp);
+        waitForIdle();
+        inOrder.verify(mHardware).setDataLimit(mobileIface, mobileLimit);
+
+        // Setting a limit of ITetheringStatsProvider.QUOTA_UNLIMITED causes the limit to be set
+        // to Long.MAX_VALUE.
+        mTetherStatsProvider.onSetLimit(mobileIface, ITetheringStatsProvider.QUOTA_UNLIMITED);
+        waitForIdle();
+        inOrder.verify(mHardware).setDataLimit(mobileIface, Long.MAX_VALUE);
+
+        // If setting upstream parameters fails, then the data limit is not set.
+        when(mHardware.setUpstreamParameters(any(), any(), any(), any())).thenReturn(false);
+        lp.setInterfaceName(ethernetIface);
+        offload.setUpstreamLinkProperties(lp);
+        mTetherStatsProvider.onSetLimit(mobileIface, mobileLimit);
+        waitForIdle();
+        inOrder.verify(mHardware, never()).setDataLimit(anyString(), anyLong());
+
+        // If setting the data limit fails while changing upstreams, offload is stopped.
+        when(mHardware.setUpstreamParameters(any(), any(), any(), any())).thenReturn(true);
+        when(mHardware.setDataLimit(anyString(), anyLong())).thenReturn(false);
+        lp.setInterfaceName(mobileIface);
+        offload.setUpstreamLinkProperties(lp);
+        mTetherStatsProvider.onSetLimit(mobileIface, mobileLimit);
+        waitForIdle();
+        inOrder.verify(mHardware).getForwardedStats(ethernetIface);
+        inOrder.verify(mHardware).stopOffloadControl();
+    }
+
+    @Test
+    public void testDataLimitCallback() throws Exception {
+        setupFunctioningHardwareInterface();
+        enableOffload();
+
+        final OffloadController offload = makeOffloadController();
+        offload.start();
+
+        OffloadHardwareInterface.ControlCallback callback = mControlCallbackCaptor.getValue();
+        callback.onStoppedLimitReached();
+        mTetherStatsProviderCb.expectNotifyStatsUpdated();
+    }
+
+    @Test
+    public void testAddRemoveDownstreams() throws Exception {
+        setupFunctioningHardwareInterface();
+        enableOffload();
+
+        final OffloadController offload = makeOffloadController();
+        offload.start();
+
+        final InOrder inOrder = inOrder(mHardware);
+        inOrder.verify(mHardware, times(1)).initOffloadConfig();
+        inOrder.verify(mHardware, times(1)).initOffloadControl(
+                any(OffloadHardwareInterface.ControlCallback.class));
+        inOrder.verifyNoMoreInteractions();
+
+        // Tethering makes several calls to setLocalPrefixes() before add/remove
+        // downstream calls are made. This is not tested here; only the behavior
+        // of notifyDownstreamLinkProperties() and removeDownstreamInterface()
+        // are tested.
+
+        // [1] USB tethering is started.
+        final LinkProperties usbLinkProperties = new LinkProperties();
+        usbLinkProperties.setInterfaceName(RNDIS0);
+        usbLinkProperties.addLinkAddress(new LinkAddress("192.168.42.1/24"));
+        usbLinkProperties.addRoute(
+                new RouteInfo(new IpPrefix(USB_PREFIX), null, null, RTN_UNICAST));
+        offload.notifyDownstreamLinkProperties(usbLinkProperties);
+        inOrder.verify(mHardware, times(1)).addDownstreamPrefix(RNDIS0, USB_PREFIX);
+        inOrder.verifyNoMoreInteractions();
+
+        // [2] Routes for IPv6 link-local prefixes should never be added.
+        usbLinkProperties.addRoute(
+                new RouteInfo(new IpPrefix(IPV6_LINKLOCAL), null, null, RTN_UNICAST));
+        offload.notifyDownstreamLinkProperties(usbLinkProperties);
+        inOrder.verify(mHardware, never()).addDownstreamPrefix(eq(RNDIS0), anyString());
+        inOrder.verifyNoMoreInteractions();
+
+        // [3] Add an IPv6 prefix for good measure. Only new offload-able
+        // prefixes should be passed to the HAL.
+        usbLinkProperties.addLinkAddress(new LinkAddress("2001:db8::1/64"));
+        usbLinkProperties.addRoute(
+                new RouteInfo(new IpPrefix(IPV6_DOC_PREFIX), null, null, RTN_UNICAST));
+        offload.notifyDownstreamLinkProperties(usbLinkProperties);
+        inOrder.verify(mHardware, times(1)).addDownstreamPrefix(RNDIS0, IPV6_DOC_PREFIX);
+        inOrder.verifyNoMoreInteractions();
+
+        // [4] Adding addresses doesn't affect notifyDownstreamLinkProperties().
+        // The address is passed in by a separate setLocalPrefixes() invocation.
+        usbLinkProperties.addLinkAddress(new LinkAddress("2001:db8::2/64"));
+        offload.notifyDownstreamLinkProperties(usbLinkProperties);
+        inOrder.verify(mHardware, never()).addDownstreamPrefix(eq(RNDIS0), anyString());
+
+        // [5] Differences in local routes are converted into addDownstream()
+        // and removeDownstream() invocations accordingly.
+        usbLinkProperties.removeRoute(
+                new RouteInfo(new IpPrefix(IPV6_DOC_PREFIX), null, RNDIS0, RTN_UNICAST));
+        usbLinkProperties.addRoute(
+                new RouteInfo(new IpPrefix(IPV6_DISCARD_PREFIX), null, null, RTN_UNICAST));
+        offload.notifyDownstreamLinkProperties(usbLinkProperties);
+        inOrder.verify(mHardware, times(1)).removeDownstreamPrefix(RNDIS0, IPV6_DOC_PREFIX);
+        inOrder.verify(mHardware, times(1)).addDownstreamPrefix(RNDIS0, IPV6_DISCARD_PREFIX);
+        inOrder.verifyNoMoreInteractions();
+
+        // [6] Removing a downstream interface which was never added causes no
+        // interactions with the HAL.
+        offload.removeDownstreamInterface(WLAN0);
+        inOrder.verifyNoMoreInteractions();
+
+        // [7] Removing an active downstream removes all remaining prefixes.
+        offload.removeDownstreamInterface(RNDIS0);
+        inOrder.verify(mHardware, times(1)).removeDownstreamPrefix(RNDIS0, USB_PREFIX);
+        inOrder.verify(mHardware, times(1)).removeDownstreamPrefix(RNDIS0, IPV6_DISCARD_PREFIX);
+        inOrder.verifyNoMoreInteractions();
+    }
+
+    @Test
+    public void testControlCallbackOnStoppedUnsupportedFetchesAllStats() throws Exception {
+        setupFunctioningHardwareInterface();
+        enableOffload();
+
+        final OffloadController offload = makeOffloadController();
+        offload.start();
+
+        // Pretend to set a few different upstreams (only the interface name
+        // matters for this test; we're ignoring IP and route information).
+        final LinkProperties upstreamLp = new LinkProperties();
+        for (String ifname : new String[]{RMNET0, WLAN0, RMNET0}) {
+            upstreamLp.setInterfaceName(ifname);
+            offload.setUpstreamLinkProperties(upstreamLp);
+        }
+
+        // Clear invocation history, especially the getForwardedStats() calls
+        // that happen with setUpstreamParameters().
+        clearInvocations(mHardware);
+
+        OffloadHardwareInterface.ControlCallback callback = mControlCallbackCaptor.getValue();
+        callback.onStoppedUnsupported();
+
+        // Verify forwarded stats behaviour.
+        verify(mHardware, times(1)).getForwardedStats(eq(RMNET0));
+        verify(mHardware, times(1)).getForwardedStats(eq(WLAN0));
+        // TODO: verify the exact stats reported.
+        mTetherStatsProviderCb.expectNotifyStatsUpdated();
+        mTetherStatsProviderCb.assertNoCallback();
+        verifyNoMoreInteractions(mHardware);
+    }
+
+    @Test
+    public void testControlCallbackOnSupportAvailableFetchesAllStatsAndPushesAllParameters()
+            throws Exception {
+        setupFunctioningHardwareInterface();
+        enableOffload();
+
+        final OffloadController offload = makeOffloadController();
+        offload.start();
+
+        // Pretend to set a few different upstreams (only the interface name
+        // matters for this test; we're ignoring IP and route information).
+        final LinkProperties upstreamLp = new LinkProperties();
+        for (String ifname : new String[]{RMNET0, WLAN0, RMNET0}) {
+            upstreamLp.setInterfaceName(ifname);
+            offload.setUpstreamLinkProperties(upstreamLp);
+        }
+
+        // Pretend that some local prefixes and downstreams have been added
+        // (and removed, for good measure).
+        final Set<IpPrefix> minimumLocalPrefixes = new HashSet<>();
+        for (String s : new String[]{
+                "127.0.0.0/8", "192.0.2.0/24", "fe80::/64", "2001:db8::/64"}) {
+            minimumLocalPrefixes.add(new IpPrefix(s));
+        }
+        offload.setLocalPrefixes(minimumLocalPrefixes);
+
+        final LinkProperties usbLinkProperties = new LinkProperties();
+        usbLinkProperties.setInterfaceName(RNDIS0);
+        usbLinkProperties.addLinkAddress(new LinkAddress("192.168.42.1/24"));
+        usbLinkProperties.addRoute(
+                new RouteInfo(new IpPrefix(USB_PREFIX), null, null, RTN_UNICAST));
+        offload.notifyDownstreamLinkProperties(usbLinkProperties);
+
+        final LinkProperties wifiLinkProperties = new LinkProperties();
+        wifiLinkProperties.setInterfaceName(WLAN0);
+        wifiLinkProperties.addLinkAddress(new LinkAddress("192.168.43.1/24"));
+        wifiLinkProperties.addRoute(
+                new RouteInfo(new IpPrefix(WIFI_PREFIX), null, null, RTN_UNICAST));
+        wifiLinkProperties.addRoute(
+                new RouteInfo(new IpPrefix(IPV6_LINKLOCAL), null, null, RTN_UNICAST));
+        // Use a benchmark prefix (RFC 5180 + erratum), since the documentation
+        // prefix is included in the excluded prefix list.
+        wifiLinkProperties.addLinkAddress(new LinkAddress("2001:2::1/64"));
+        wifiLinkProperties.addLinkAddress(new LinkAddress("2001:2::2/64"));
+        wifiLinkProperties.addRoute(
+                new RouteInfo(new IpPrefix("2001:2::/64"), null, null, RTN_UNICAST));
+        offload.notifyDownstreamLinkProperties(wifiLinkProperties);
+
+        offload.removeDownstreamInterface(RNDIS0);
+
+        // Clear invocation history, especially the getForwardedStats() calls
+        // that happen with setUpstreamParameters().
+        clearInvocations(mHardware);
+
+        OffloadHardwareInterface.ControlCallback callback = mControlCallbackCaptor.getValue();
+        callback.onSupportAvailable();
+
+        // Verify forwarded stats behaviour.
+        verify(mHardware, times(1)).getForwardedStats(eq(RMNET0));
+        verify(mHardware, times(1)).getForwardedStats(eq(WLAN0));
+        mTetherStatsProviderCb.expectNotifyStatsUpdated();
+        mTetherStatsProviderCb.assertNoCallback();
+
+        // TODO: verify local prefixes and downstreams are also pushed to the HAL.
+        verify(mHardware, times(1)).setLocalPrefixes(mStringArrayCaptor.capture());
+        ArrayList<String> localPrefixes = mStringArrayCaptor.getValue();
+        assertEquals(4, localPrefixes.size());
+        assertContainsAll(localPrefixes,
+                // TODO: The logic to find and exclude downstream IP prefixes
+                // is currently in Tethering's OffloadWrapper but must be moved
+                // into OffloadController proper. After this, also check for:
+                //     "192.168.43.1/32", "2001:2::1/128", "2001:2::2/128"
+                "127.0.0.0/8", "192.0.2.0/24", "fe80::/64", "2001:db8::/64");
+        verify(mHardware, times(1)).addDownstreamPrefix(WLAN0, "192.168.43.0/24");
+        verify(mHardware, times(1)).addDownstreamPrefix(WLAN0, "2001:2::/64");
+        verify(mHardware, times(1)).setUpstreamParameters(eq(RMNET0), any(), any(), any());
+        verify(mHardware, times(1)).setDataLimit(eq(RMNET0), anyLong());
+        verifyNoMoreInteractions(mHardware);
+    }
+
+    @Test
+    public void testOnSetAlert() throws Exception {
+        setupFunctioningHardwareInterface();
+        enableOffload();
+        setOffloadPollInterval(DEFAULT_TETHER_OFFLOAD_POLL_INTERVAL_MS);
+        final OffloadController offload = makeOffloadController();
+        offload.start();
+
+        // Initialize with fake eth upstream.
+        final String ethernetIface = "eth1";
+        InOrder inOrder = inOrder(mHardware);
+        final LinkProperties lp = new LinkProperties();
+        lp.setInterfaceName(ethernetIface);
+        offload.setUpstreamLinkProperties(lp);
+        // Previous upstream was null, so no stats are fetched.
+        inOrder.verify(mHardware, never()).getForwardedStats(any());
+
+        // Verify that set quota to 0 will immediately triggers an callback.
+        mTetherStatsProvider.onSetAlert(0);
+        waitForIdle();
+        mTetherStatsProviderCb.expectNotifyAlertReached();
+
+        // Verify that notifyAlertReached never fired if quota is not yet reached.
+        when(mHardware.getForwardedStats(eq(ethernetIface))).thenReturn(
+                new ForwardedStats(0, 0));
+        mTetherStatsProvider.onSetAlert(100);
+        mTestLooper.moveTimeForward(DEFAULT_TETHER_OFFLOAD_POLL_INTERVAL_MS);
+        waitForIdle();
+        mTetherStatsProviderCb.assertNoCallback();
+
+        // Verify that notifyAlertReached fired when quota is reached.
+        when(mHardware.getForwardedStats(eq(ethernetIface))).thenReturn(
+                new ForwardedStats(50, 50));
+        mTestLooper.moveTimeForward(DEFAULT_TETHER_OFFLOAD_POLL_INTERVAL_MS);
+        waitForIdle();
+        mTetherStatsProviderCb.expectNotifyAlertReached();
+
+        // Verify that set quota with UNLIMITED won't trigger any callback, and won't fetch
+        // any stats since the polling is stopped.
+        reset(mHardware);
+        mTetherStatsProvider.onSetAlert(NetworkStatsProvider.QUOTA_UNLIMITED);
+        mTestLooper.moveTimeForward(DEFAULT_TETHER_OFFLOAD_POLL_INTERVAL_MS);
+        waitForIdle();
+        mTetherStatsProviderCb.assertNoCallback();
+        verify(mHardware, never()).getForwardedStats(any());
+    }
+}
diff --git a/Tethering/tests/unit/src/com/android/networkstack/tethering/OffloadHardwareInterfaceTest.java b/Tethering/tests/unit/src/com/android/networkstack/tethering/OffloadHardwareInterfaceTest.java
new file mode 100644
index 0000000..38b19dd
--- /dev/null
+++ b/Tethering/tests/unit/src/com/android/networkstack/tethering/OffloadHardwareInterfaceTest.java
@@ -0,0 +1,264 @@
+/*
+ * Copyright (C) 2020 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.android.networkstack.tethering;
+
+import static android.net.util.TetheringUtils.uint16;
+import static android.system.OsConstants.AF_INET;
+import static android.system.OsConstants.AF_UNIX;
+import static android.system.OsConstants.SOCK_STREAM;
+
+import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertNotNull;
+import static org.junit.Assert.fail;
+import static org.mockito.ArgumentMatchers.any;
+import static org.mockito.ArgumentMatchers.eq;
+import static org.mockito.Mockito.spy;
+import static org.mockito.Mockito.verify;
+import static org.mockito.Mockito.when;
+
+import android.hardware.tetheroffload.config.V1_0.IOffloadConfig;
+import android.hardware.tetheroffload.control.V1_0.IOffloadControl;
+import android.hardware.tetheroffload.control.V1_0.ITetheringOffloadCallback;
+import android.hardware.tetheroffload.control.V1_0.NatTimeoutUpdate;
+import android.hardware.tetheroffload.control.V1_0.NetworkProtocol;
+import android.hardware.tetheroffload.control.V1_0.OffloadCallbackEvent;
+import android.net.netlink.StructNfGenMsg;
+import android.net.netlink.StructNlMsgHdr;
+import android.net.util.SharedLog;
+import android.os.Handler;
+import android.os.NativeHandle;
+import android.os.test.TestLooper;
+import android.system.ErrnoException;
+import android.system.Os;
+import android.system.OsConstants;
+
+import androidx.test.filters.SmallTest;
+import androidx.test.runner.AndroidJUnit4;
+
+import org.junit.Before;
+import org.junit.Test;
+import org.junit.runner.RunWith;
+import org.mockito.ArgumentCaptor;
+import org.mockito.Mock;
+import org.mockito.MockitoAnnotations;
+
+import java.io.FileDescriptor;
+import java.nio.ByteBuffer;
+import java.nio.ByteOrder;
+import java.util.ArrayList;
+
+@RunWith(AndroidJUnit4.class)
+@SmallTest
+public final class OffloadHardwareInterfaceTest {
+    private static final String RMNET0 = "test_rmnet_data0";
+
+    private final TestLooper mTestLooper = new TestLooper();
+
+    private OffloadHardwareInterface mOffloadHw;
+    private ITetheringOffloadCallback mTetheringOffloadCallback;
+    private OffloadHardwareInterface.ControlCallback mControlCallback;
+
+    @Mock private IOffloadConfig mIOffloadConfig;
+    @Mock private IOffloadControl mIOffloadControl;
+    @Mock private NativeHandle mNativeHandle;
+
+    // Random values to test Netlink message.
+    private static final short TEST_TYPE = 184;
+    private static final short TEST_FLAGS = 263;
+
+    class MyDependencies extends OffloadHardwareInterface.Dependencies {
+        MyDependencies(SharedLog log) {
+            super(log);
+        }
+
+        @Override
+        public IOffloadConfig getOffloadConfig() {
+            return mIOffloadConfig;
+        }
+
+        @Override
+        public IOffloadControl getOffloadControl() {
+            return mIOffloadControl;
+        }
+
+        @Override
+        public NativeHandle createConntrackSocket(final int groups) {
+            return mNativeHandle;
+        }
+    }
+
+    @Before
+    public void setUp() {
+        MockitoAnnotations.initMocks(this);
+        final SharedLog log = new SharedLog("test");
+        mOffloadHw = new OffloadHardwareInterface(new Handler(mTestLooper.getLooper()), log,
+                new MyDependencies(log));
+        mControlCallback = spy(new OffloadHardwareInterface.ControlCallback());
+    }
+
+    private void startOffloadHardwareInterface() throws Exception {
+        mOffloadHw.initOffloadConfig();
+        mOffloadHw.initOffloadControl(mControlCallback);
+        final ArgumentCaptor<ITetheringOffloadCallback> mOffloadCallbackCaptor =
+                ArgumentCaptor.forClass(ITetheringOffloadCallback.class);
+        verify(mIOffloadControl).initOffload(mOffloadCallbackCaptor.capture(), any());
+        mTetheringOffloadCallback = mOffloadCallbackCaptor.getValue();
+    }
+
+    @Test
+    public void testGetForwardedStats() throws Exception {
+        startOffloadHardwareInterface();
+        final OffloadHardwareInterface.ForwardedStats stats = mOffloadHw.getForwardedStats(RMNET0);
+        verify(mIOffloadControl).getForwardedStats(eq(RMNET0), any());
+        assertNotNull(stats);
+    }
+
+    @Test
+    public void testSetLocalPrefixes() throws Exception {
+        startOffloadHardwareInterface();
+        final ArrayList<String> localPrefixes = new ArrayList<>();
+        localPrefixes.add("127.0.0.0/8");
+        localPrefixes.add("fe80::/64");
+        mOffloadHw.setLocalPrefixes(localPrefixes);
+        verify(mIOffloadControl).setLocalPrefixes(eq(localPrefixes), any());
+    }
+
+    @Test
+    public void testSetDataLimit() throws Exception {
+        startOffloadHardwareInterface();
+        final long limit = 12345;
+        mOffloadHw.setDataLimit(RMNET0, limit);
+        verify(mIOffloadControl).setDataLimit(eq(RMNET0), eq(limit), any());
+    }
+
+    @Test
+    public void testSetUpstreamParameters() throws Exception {
+        startOffloadHardwareInterface();
+        final String v4addr = "192.168.10.1";
+        final String v4gateway = "192.168.10.255";
+        final ArrayList<String> v6gws = new ArrayList<>(0);
+        v6gws.add("2001:db8::1");
+        mOffloadHw.setUpstreamParameters(RMNET0, v4addr, v4gateway, v6gws);
+        verify(mIOffloadControl).setUpstreamParameters(eq(RMNET0), eq(v4addr), eq(v4gateway),
+                eq(v6gws), any());
+
+        final ArgumentCaptor<ArrayList<String>> mArrayListCaptor =
+                ArgumentCaptor.forClass(ArrayList.class);
+        mOffloadHw.setUpstreamParameters(null, null, null, null);
+        verify(mIOffloadControl).setUpstreamParameters(eq(""), eq(""), eq(""),
+                mArrayListCaptor.capture(), any());
+        assertEquals(mArrayListCaptor.getValue().size(), 0);
+    }
+
+    @Test
+    public void testUpdateDownstreamPrefix() throws Exception {
+        startOffloadHardwareInterface();
+        final String ifName = "wlan1";
+        final String prefix = "192.168.43.0/24";
+        mOffloadHw.addDownstreamPrefix(ifName, prefix);
+        verify(mIOffloadControl).addDownstream(eq(ifName), eq(prefix), any());
+
+        mOffloadHw.removeDownstreamPrefix(ifName, prefix);
+        verify(mIOffloadControl).removeDownstream(eq(ifName), eq(prefix), any());
+    }
+
+    @Test
+    public void testTetheringOffloadCallback() throws Exception {
+        startOffloadHardwareInterface();
+
+        mTetheringOffloadCallback.onEvent(OffloadCallbackEvent.OFFLOAD_STARTED);
+        mTestLooper.dispatchAll();
+        verify(mControlCallback).onStarted();
+
+        mTetheringOffloadCallback.onEvent(OffloadCallbackEvent.OFFLOAD_STOPPED_ERROR);
+        mTestLooper.dispatchAll();
+        verify(mControlCallback).onStoppedError();
+
+        mTetheringOffloadCallback.onEvent(OffloadCallbackEvent.OFFLOAD_STOPPED_UNSUPPORTED);
+        mTestLooper.dispatchAll();
+        verify(mControlCallback).onStoppedUnsupported();
+
+        mTetheringOffloadCallback.onEvent(OffloadCallbackEvent.OFFLOAD_SUPPORT_AVAILABLE);
+        mTestLooper.dispatchAll();
+        verify(mControlCallback).onSupportAvailable();
+
+        mTetheringOffloadCallback.onEvent(OffloadCallbackEvent.OFFLOAD_STOPPED_LIMIT_REACHED);
+        mTestLooper.dispatchAll();
+        verify(mControlCallback).onStoppedLimitReached();
+
+        final NatTimeoutUpdate tcpParams = buildNatTimeoutUpdate(NetworkProtocol.TCP);
+        mTetheringOffloadCallback.updateTimeout(tcpParams);
+        mTestLooper.dispatchAll();
+        verify(mControlCallback).onNatTimeoutUpdate(eq(OsConstants.IPPROTO_TCP),
+                eq(tcpParams.src.addr),
+                eq(uint16(tcpParams.src.port)),
+                eq(tcpParams.dst.addr),
+                eq(uint16(tcpParams.dst.port)));
+
+        final NatTimeoutUpdate udpParams = buildNatTimeoutUpdate(NetworkProtocol.UDP);
+        mTetheringOffloadCallback.updateTimeout(udpParams);
+        mTestLooper.dispatchAll();
+        verify(mControlCallback).onNatTimeoutUpdate(eq(OsConstants.IPPROTO_UDP),
+                eq(udpParams.src.addr),
+                eq(uint16(udpParams.src.port)),
+                eq(udpParams.dst.addr),
+                eq(uint16(udpParams.dst.port)));
+    }
+
+    @Test
+    public void testSendIpv4NfGenMsg() throws Exception {
+        FileDescriptor writeSocket = new FileDescriptor();
+        FileDescriptor readSocket = new FileDescriptor();
+        try {
+            Os.socketpair(AF_UNIX, SOCK_STREAM, 0, writeSocket, readSocket);
+        } catch (ErrnoException e) {
+            fail();
+            return;
+        }
+        when(mNativeHandle.getFileDescriptor()).thenReturn(writeSocket);
+
+        mOffloadHw.sendIpv4NfGenMsg(mNativeHandle, TEST_TYPE, TEST_FLAGS);
+
+        ByteBuffer buffer = ByteBuffer.allocate(9823);  // Arbitrary value > expectedLen.
+        buffer.order(ByteOrder.nativeOrder());
+
+        int read = Os.read(readSocket, buffer);
+        final int expectedLen = StructNlMsgHdr.STRUCT_SIZE + StructNfGenMsg.STRUCT_SIZE;
+        assertEquals(expectedLen, read);
+
+        buffer.flip();
+        assertEquals(expectedLen, buffer.getInt());
+        assertEquals(TEST_TYPE, buffer.getShort());
+        assertEquals(TEST_FLAGS, buffer.getShort());
+        assertEquals(0 /* seq */, buffer.getInt());
+        assertEquals(0 /* pid */, buffer.getInt());
+        assertEquals(AF_INET, buffer.get());             // nfgen_family
+        assertEquals(0 /* error */, buffer.get());       // version
+        assertEquals(0 /* error */, buffer.getShort());  // res_id
+        assertEquals(expectedLen, buffer.position());
+    }
+
+    private NatTimeoutUpdate buildNatTimeoutUpdate(final int proto) {
+        final NatTimeoutUpdate params = new NatTimeoutUpdate();
+        params.proto = proto;
+        params.src.addr = "192.168.43.200";
+        params.src.port = 100;
+        params.dst.addr = "172.50.46.169";
+        params.dst.port = 150;
+        return params;
+    }
+}
diff --git a/Tethering/tests/unit/src/com/android/networkstack/tethering/PrivateAddressCoordinatorTest.java b/Tethering/tests/unit/src/com/android/networkstack/tethering/PrivateAddressCoordinatorTest.java
new file mode 100644
index 0000000..41d46e5
--- /dev/null
+++ b/Tethering/tests/unit/src/com/android/networkstack/tethering/PrivateAddressCoordinatorTest.java
@@ -0,0 +1,551 @@
+/*
+ * Copyright (C) 2020 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package com.android.networkstack.tethering;
+
+import static android.net.NetworkCapabilities.NET_CAPABILITY_NOT_VPN;
+import static android.net.NetworkCapabilities.TRANSPORT_CELLULAR;
+import static android.net.NetworkCapabilities.TRANSPORT_VPN;
+import static android.net.NetworkCapabilities.TRANSPORT_WIFI;
+import static android.net.TetheringManager.TETHERING_ETHERNET;
+import static android.net.TetheringManager.TETHERING_USB;
+import static android.net.TetheringManager.TETHERING_WIFI;
+import static android.net.TetheringManager.TETHERING_WIFI_P2P;
+import static android.net.util.PrefixUtils.asIpPrefix;
+
+import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertNotEquals;
+import static org.mockito.Mockito.never;
+import static org.mockito.Mockito.reset;
+import static org.mockito.Mockito.spy;
+import static org.mockito.Mockito.verify;
+import static org.mockito.Mockito.when;
+
+import android.content.Context;
+import android.net.ConnectivityManager;
+import android.net.IpPrefix;
+import android.net.LinkAddress;
+import android.net.LinkProperties;
+import android.net.Network;
+import android.net.NetworkCapabilities;
+import android.net.ip.IpServer;
+
+import androidx.test.filters.SmallTest;
+import androidx.test.runner.AndroidJUnit4;
+
+import org.junit.Before;
+import org.junit.Test;
+import org.junit.runner.RunWith;
+import org.mockito.Mock;
+import org.mockito.MockitoAnnotations;
+
+import java.util.ArrayList;
+import java.util.Arrays;
+
+@RunWith(AndroidJUnit4.class)
+@SmallTest
+public final class PrivateAddressCoordinatorTest {
+    private static final String TEST_IFNAME = "test0";
+
+    @Mock private IpServer mHotspotIpServer;
+    @Mock private IpServer mUsbIpServer;
+    @Mock private IpServer mEthernetIpServer;
+    @Mock private IpServer mWifiP2pIpServer;
+    @Mock private Context mContext;
+    @Mock private ConnectivityManager mConnectivityMgr;
+    @Mock private TetheringConfiguration mConfig;
+
+    private PrivateAddressCoordinator mPrivateAddressCoordinator;
+    private final LinkAddress mBluetoothAddress = new LinkAddress("192.168.44.1/24");
+    private final LinkAddress mLegacyWifiP2pAddress = new LinkAddress("192.168.49.1/24");
+    private final Network mWifiNetwork = new Network(1);
+    private final Network mMobileNetwork = new Network(2);
+    private final Network mVpnNetwork = new Network(3);
+    private final Network mMobileNetwork2 = new Network(4);
+    private final Network mMobileNetwork3 = new Network(5);
+    private final Network mMobileNetwork4 = new Network(6);
+    private final Network mMobileNetwork5 = new Network(7);
+    private final Network mMobileNetwork6 = new Network(8);
+    private final Network[] mAllNetworks = {mMobileNetwork, mWifiNetwork, mVpnNetwork,
+            mMobileNetwork2, mMobileNetwork3, mMobileNetwork4, mMobileNetwork5, mMobileNetwork6};
+    private final ArrayList<IpPrefix> mTetheringPrefixes = new ArrayList<>(Arrays.asList(
+            new IpPrefix("192.168.0.0/16"),
+            new IpPrefix("172.16.0.0/12"),
+            new IpPrefix("10.0.0.0/8")));
+
+    private void setUpIpServers() throws Exception {
+        when(mUsbIpServer.interfaceType()).thenReturn(TETHERING_USB);
+        when(mEthernetIpServer.interfaceType()).thenReturn(TETHERING_ETHERNET);
+        when(mHotspotIpServer.interfaceType()).thenReturn(TETHERING_WIFI);
+        when(mWifiP2pIpServer.interfaceType()).thenReturn(TETHERING_WIFI_P2P);
+    }
+
+    @Before
+    public void setUp() throws Exception {
+        MockitoAnnotations.initMocks(this);
+
+        when(mContext.getSystemService(Context.CONNECTIVITY_SERVICE)).thenReturn(mConnectivityMgr);
+        when(mConnectivityMgr.getAllNetworks()).thenReturn(mAllNetworks);
+        when(mConfig.shouldEnableWifiP2pDedicatedIp()).thenReturn(false);
+        when(mConfig.isSelectAllPrefixRangeEnabled()).thenReturn(true);
+        setUpIpServers();
+        mPrivateAddressCoordinator = spy(new PrivateAddressCoordinator(mContext, mConfig));
+    }
+
+    private LinkAddress requestDownstreamAddress(final IpServer ipServer, boolean useLastAddress) {
+        final LinkAddress address = mPrivateAddressCoordinator.requestDownstreamAddress(
+                ipServer, useLastAddress);
+        when(ipServer.getAddress()).thenReturn(address);
+        return address;
+    }
+
+    @Test
+    public void testRequestDownstreamAddressWithoutUsingLastAddress() throws Exception {
+        final IpPrefix bluetoothPrefix = asIpPrefix(mBluetoothAddress);
+        final LinkAddress address = requestDownstreamAddress(mHotspotIpServer,
+                false /* useLastAddress */);
+        final IpPrefix hotspotPrefix = asIpPrefix(address);
+        assertNotEquals(hotspotPrefix, bluetoothPrefix);
+
+        final LinkAddress newAddress = requestDownstreamAddress(mHotspotIpServer,
+                false /* useLastAddress */);
+        final IpPrefix testDupRequest = asIpPrefix(newAddress);
+        assertNotEquals(hotspotPrefix, testDupRequest);
+        assertNotEquals(bluetoothPrefix, testDupRequest);
+        mPrivateAddressCoordinator.releaseDownstream(mHotspotIpServer);
+
+        final LinkAddress usbAddress = requestDownstreamAddress(mUsbIpServer,
+                false /* useLastAddress */);
+        final IpPrefix usbPrefix = asIpPrefix(usbAddress);
+        assertNotEquals(usbPrefix, bluetoothPrefix);
+        assertNotEquals(usbPrefix, hotspotPrefix);
+        mPrivateAddressCoordinator.releaseDownstream(mUsbIpServer);
+    }
+
+    @Test
+    public void testSanitizedAddress() throws Exception {
+        int fakeSubAddr = 0x2b00; // 43.0.
+        when(mPrivateAddressCoordinator.getRandomInt()).thenReturn(fakeSubAddr);
+        LinkAddress actualAddress = requestDownstreamAddress(mHotspotIpServer,
+                false /* useLastAddress */);
+        assertEquals(new LinkAddress("192.168.43.2/24"), actualAddress);
+        mPrivateAddressCoordinator.releaseDownstream(mHotspotIpServer);
+
+        fakeSubAddr = 0x2d01; // 45.1.
+        when(mPrivateAddressCoordinator.getRandomInt()).thenReturn(fakeSubAddr);
+        actualAddress = requestDownstreamAddress(mHotspotIpServer, false /* useLastAddress */);
+        assertEquals(new LinkAddress("192.168.45.2/24"), actualAddress);
+        mPrivateAddressCoordinator.releaseDownstream(mHotspotIpServer);
+
+        fakeSubAddr = 0x2eff; // 46.255.
+        when(mPrivateAddressCoordinator.getRandomInt()).thenReturn(fakeSubAddr);
+        actualAddress = requestDownstreamAddress(mHotspotIpServer, false /* useLastAddress */);
+        assertEquals(new LinkAddress("192.168.46.254/24"), actualAddress);
+        mPrivateAddressCoordinator.releaseDownstream(mHotspotIpServer);
+
+        fakeSubAddr = 0x2f05; // 47.5.
+        when(mPrivateAddressCoordinator.getRandomInt()).thenReturn(fakeSubAddr);
+        actualAddress = requestDownstreamAddress(mHotspotIpServer, false /* useLastAddress */);
+        assertEquals(new LinkAddress("192.168.47.5/24"), actualAddress);
+        mPrivateAddressCoordinator.releaseDownstream(mHotspotIpServer);
+    }
+
+    @Test
+    public void testReservedPrefix() throws Exception {
+        // - Test bluetooth prefix is reserved.
+        when(mPrivateAddressCoordinator.getRandomInt()).thenReturn(
+                getSubAddress(mBluetoothAddress.getAddress().getAddress()));
+        final LinkAddress hotspotAddress = requestDownstreamAddress(mHotspotIpServer,
+                false /* useLastAddress */);
+        final IpPrefix hotspotPrefix = asIpPrefix(hotspotAddress);
+        assertNotEquals(asIpPrefix(mBluetoothAddress), hotspotPrefix);
+        mPrivateAddressCoordinator.releaseDownstream(mHotspotIpServer);
+
+        // - Test previous enabled hotspot prefix(cached prefix) is reserved.
+        when(mPrivateAddressCoordinator.getRandomInt()).thenReturn(
+                getSubAddress(hotspotAddress.getAddress().getAddress()));
+        final LinkAddress usbAddress = requestDownstreamAddress(mUsbIpServer,
+                false /* useLastAddress */);
+        final IpPrefix usbPrefix = asIpPrefix(usbAddress);
+        assertNotEquals(asIpPrefix(mBluetoothAddress), usbPrefix);
+        assertNotEquals(hotspotPrefix, usbPrefix);
+        mPrivateAddressCoordinator.releaseDownstream(mUsbIpServer);
+
+        // - Test wifi p2p prefix is reserved.
+        when(mPrivateAddressCoordinator.getRandomInt()).thenReturn(
+                getSubAddress(mLegacyWifiP2pAddress.getAddress().getAddress()));
+        final LinkAddress etherAddress = requestDownstreamAddress(mEthernetIpServer,
+                false /* useLastAddress */);
+        final IpPrefix etherPrefix = asIpPrefix(etherAddress);
+        assertNotEquals(asIpPrefix(mLegacyWifiP2pAddress), etherPrefix);
+        assertNotEquals(asIpPrefix(mBluetoothAddress), etherPrefix);
+        assertNotEquals(hotspotPrefix, etherPrefix);
+        mPrivateAddressCoordinator.releaseDownstream(mEthernetIpServer);
+    }
+
+    @Test
+    public void testRequestLastDownstreamAddress() throws Exception {
+        final int fakeHotspotSubAddr = 0x2b05; // 43.5
+        when(mPrivateAddressCoordinator.getRandomInt()).thenReturn(fakeHotspotSubAddr);
+        final LinkAddress hotspotAddress = requestDownstreamAddress(mHotspotIpServer,
+                true /* useLastAddress */);
+        assertEquals("Wrong wifi prefix: ", new LinkAddress("192.168.43.5/24"), hotspotAddress);
+
+        final LinkAddress usbAddress = requestDownstreamAddress(mUsbIpServer,
+                true /* useLastAddress */);
+        assertEquals("Wrong wifi prefix: ", new LinkAddress("192.168.45.5/24"), usbAddress);
+
+        mPrivateAddressCoordinator.releaseDownstream(mHotspotIpServer);
+        mPrivateAddressCoordinator.releaseDownstream(mUsbIpServer);
+
+        final int newFakeSubAddr = 0x3c05;
+        when(mPrivateAddressCoordinator.getRandomInt()).thenReturn(fakeHotspotSubAddr);
+
+        final LinkAddress newHotspotAddress = requestDownstreamAddress(mHotspotIpServer,
+                true /* useLastAddress */);
+        assertEquals(hotspotAddress, newHotspotAddress);
+        final LinkAddress newUsbAddress = requestDownstreamAddress(mUsbIpServer,
+                true /* useLastAddress */);
+        assertEquals(usbAddress, newUsbAddress);
+
+        final UpstreamNetworkState wifiUpstream = buildUpstreamNetworkState(mWifiNetwork,
+                new LinkAddress("192.168.88.23/16"), null,
+                makeNetworkCapabilities(TRANSPORT_WIFI));
+        mPrivateAddressCoordinator.updateUpstreamPrefix(wifiUpstream);
+        verify(mHotspotIpServer).sendMessage(IpServer.CMD_NOTIFY_PREFIX_CONFLICT);
+        verify(mUsbIpServer).sendMessage(IpServer.CMD_NOTIFY_PREFIX_CONFLICT);
+    }
+
+    private UpstreamNetworkState buildUpstreamNetworkState(final Network network,
+            final LinkAddress v4Addr, final LinkAddress v6Addr, final NetworkCapabilities cap) {
+        final LinkProperties prop = new LinkProperties();
+        prop.setInterfaceName(TEST_IFNAME);
+        if (v4Addr != null) prop.addLinkAddress(v4Addr);
+
+        if (v6Addr != null) prop.addLinkAddress(v6Addr);
+
+        return new UpstreamNetworkState(prop, cap, network);
+    }
+
+    private NetworkCapabilities makeNetworkCapabilities(final int transportType) {
+        final NetworkCapabilities cap = new NetworkCapabilities();
+        cap.addTransportType(transportType);
+        if (transportType == TRANSPORT_VPN) {
+            cap.removeCapability(NET_CAPABILITY_NOT_VPN);
+        }
+
+        return cap;
+    }
+
+    @Test
+    public void testNoConflictUpstreamPrefix() throws Exception {
+        final int fakeHotspotSubAddr = 0x2b05; // 43.5
+        final IpPrefix predefinedPrefix = new IpPrefix("192.168.43.0/24");
+        // Force always get subAddress "43.5" for conflict testing.
+        when(mPrivateAddressCoordinator.getRandomInt()).thenReturn(fakeHotspotSubAddr);
+        // - Enable hotspot with prefix 192.168.43.0/24
+        final LinkAddress hotspotAddr = requestDownstreamAddress(mHotspotIpServer,
+                true /* useLastAddress */);
+        final IpPrefix hotspotPrefix = asIpPrefix(hotspotAddr);
+        assertEquals("Wrong wifi prefix: ", predefinedPrefix, hotspotPrefix);
+        // - test mobile network with null NetworkCapabilities. Ideally this should not happen
+        // because NetworkCapabilities update should always happen before LinkProperties update
+        // and the UpstreamNetworkState update, just make sure no crash in this case.
+        final UpstreamNetworkState noCapUpstream = buildUpstreamNetworkState(mMobileNetwork,
+                new LinkAddress("10.0.0.8/24"), null, null);
+        mPrivateAddressCoordinator.updateUpstreamPrefix(noCapUpstream);
+        verify(mHotspotIpServer, never()).sendMessage(IpServer.CMD_NOTIFY_PREFIX_CONFLICT);
+        // - test mobile upstream with no address.
+        final UpstreamNetworkState noAddress = buildUpstreamNetworkState(mMobileNetwork,
+                null, null, makeNetworkCapabilities(TRANSPORT_CELLULAR));
+        mPrivateAddressCoordinator.updateUpstreamPrefix(noCapUpstream);
+        verify(mHotspotIpServer, never()).sendMessage(IpServer.CMD_NOTIFY_PREFIX_CONFLICT);
+        // - Update v6 only mobile network, hotspot prefix should not be removed.
+        final UpstreamNetworkState v6OnlyMobile = buildUpstreamNetworkState(mMobileNetwork,
+                null, new LinkAddress("2001:db8::/64"),
+                makeNetworkCapabilities(TRANSPORT_CELLULAR));
+        mPrivateAddressCoordinator.updateUpstreamPrefix(v6OnlyMobile);
+        verify(mHotspotIpServer, never()).sendMessage(IpServer.CMD_NOTIFY_PREFIX_CONFLICT);
+        mPrivateAddressCoordinator.removeUpstreamPrefix(mMobileNetwork);
+        // - Update v4 only mobile network, hotspot prefix should not be removed.
+        final UpstreamNetworkState v4OnlyMobile = buildUpstreamNetworkState(mMobileNetwork,
+                new LinkAddress("10.0.0.8/24"), null,
+                makeNetworkCapabilities(TRANSPORT_CELLULAR));
+        mPrivateAddressCoordinator.updateUpstreamPrefix(v4OnlyMobile);
+        verify(mHotspotIpServer, never()).sendMessage(IpServer.CMD_NOTIFY_PREFIX_CONFLICT);
+        // - Update v4v6 mobile network, hotspot prefix should not be removed.
+        final UpstreamNetworkState v4v6Mobile = buildUpstreamNetworkState(mMobileNetwork,
+                new LinkAddress("10.0.0.8/24"), new LinkAddress("2001:db8::/64"),
+                makeNetworkCapabilities(TRANSPORT_CELLULAR));
+        mPrivateAddressCoordinator.updateUpstreamPrefix(v4v6Mobile);
+        verify(mHotspotIpServer, never()).sendMessage(IpServer.CMD_NOTIFY_PREFIX_CONFLICT);
+        // - Update v6 only wifi network, hotspot prefix should not be removed.
+        final UpstreamNetworkState v6OnlyWifi = buildUpstreamNetworkState(mWifiNetwork,
+                null, new LinkAddress("2001:db8::/64"), makeNetworkCapabilities(TRANSPORT_WIFI));
+        mPrivateAddressCoordinator.updateUpstreamPrefix(v6OnlyWifi);
+        verify(mHotspotIpServer, never()).sendMessage(IpServer.CMD_NOTIFY_PREFIX_CONFLICT);
+        mPrivateAddressCoordinator.removeUpstreamPrefix(mWifiNetwork);
+        // - Update vpn network, it conflict with hotspot prefix but VPN networks are ignored.
+        final UpstreamNetworkState v4OnlyVpn = buildUpstreamNetworkState(mVpnNetwork,
+                new LinkAddress("192.168.43.5/24"), null, makeNetworkCapabilities(TRANSPORT_VPN));
+        mPrivateAddressCoordinator.updateUpstreamPrefix(v4OnlyVpn);
+        verify(mHotspotIpServer, never()).sendMessage(IpServer.CMD_NOTIFY_PREFIX_CONFLICT);
+        // - Update v4 only wifi network, it conflict with hotspot prefix.
+        final UpstreamNetworkState v4OnlyWifi = buildUpstreamNetworkState(mWifiNetwork,
+                new LinkAddress("192.168.43.5/24"), null, makeNetworkCapabilities(TRANSPORT_WIFI));
+        mPrivateAddressCoordinator.updateUpstreamPrefix(v4OnlyWifi);
+        verify(mHotspotIpServer).sendMessage(IpServer.CMD_NOTIFY_PREFIX_CONFLICT);
+        reset(mHotspotIpServer);
+        // - Restart hotspot again and its prefix is different previous.
+        mPrivateAddressCoordinator.releaseDownstream(mHotspotIpServer);
+        final LinkAddress hotspotAddr2 = requestDownstreamAddress(mHotspotIpServer,
+                true /* useLastAddress */);
+        final IpPrefix hotspotPrefix2 = asIpPrefix(hotspotAddr2);
+        assertNotEquals(hotspotPrefix, hotspotPrefix2);
+        mPrivateAddressCoordinator.updateUpstreamPrefix(v4OnlyWifi);
+        verify(mHotspotIpServer, never()).sendMessage(IpServer.CMD_NOTIFY_PREFIX_CONFLICT);
+        // - Usb tethering can be enabled and its prefix is different with conflict one.
+        final LinkAddress usbAddr = requestDownstreamAddress(mUsbIpServer,
+                true /* useLastAddress */);
+        final IpPrefix usbPrefix = asIpPrefix(usbAddr);
+        assertNotEquals(predefinedPrefix, usbPrefix);
+        assertNotEquals(hotspotPrefix2, usbPrefix);
+        // - Disable wifi upstream, then wifi's prefix can be selected again.
+        mPrivateAddressCoordinator.removeUpstreamPrefix(mWifiNetwork);
+        final LinkAddress ethAddr = requestDownstreamAddress(mEthernetIpServer,
+                true /* useLastAddress */);
+        final IpPrefix ethPrefix = asIpPrefix(ethAddr);
+        assertEquals(predefinedPrefix, ethPrefix);
+    }
+
+    @Test
+    public void testChooseAvailablePrefix() throws Exception {
+        final int randomAddress = 0x8605; // 134.5
+        when(mPrivateAddressCoordinator.getRandomInt()).thenReturn(randomAddress);
+        final LinkAddress addr0 = requestDownstreamAddress(mHotspotIpServer,
+                true /* useLastAddress */);
+        // Check whether return address is prefix 192.168.0.0/16 + subAddress 0.0.134.5.
+        assertEquals("Wrong prefix: ", new LinkAddress("192.168.134.5/24"), addr0);
+        final UpstreamNetworkState wifiUpstream = buildUpstreamNetworkState(mWifiNetwork,
+                new LinkAddress("192.168.134.13/26"), null,
+                makeNetworkCapabilities(TRANSPORT_WIFI));
+        mPrivateAddressCoordinator.updateUpstreamPrefix(wifiUpstream);
+
+        // Check whether return address is next prefix of 192.168.134.0/24.
+        final LinkAddress addr1 = requestDownstreamAddress(mHotspotIpServer,
+                true /* useLastAddress */);
+        assertEquals("Wrong prefix: ", new LinkAddress("192.168.135.5/24"), addr1);
+        final UpstreamNetworkState wifiUpstream2 = buildUpstreamNetworkState(mWifiNetwork,
+                new LinkAddress("192.168.149.16/19"), null,
+                makeNetworkCapabilities(TRANSPORT_WIFI));
+        mPrivateAddressCoordinator.updateUpstreamPrefix(wifiUpstream2);
+
+
+        // The conflict range is 128 ~ 159, so the address is 192.168.160.5/24.
+        final LinkAddress addr2 = requestDownstreamAddress(mHotspotIpServer,
+                true /* useLastAddress */);
+        assertEquals("Wrong prefix: ", new LinkAddress("192.168.160.5/24"), addr2);
+        final UpstreamNetworkState mobileUpstream = buildUpstreamNetworkState(mMobileNetwork,
+                new LinkAddress("192.168.129.53/18"), null,
+                makeNetworkCapabilities(TRANSPORT_CELLULAR));
+        // Update another conflict upstream which is covered by the previous one (but not the first
+        // one) and verify whether this would affect the result.
+        final UpstreamNetworkState mobileUpstream2 = buildUpstreamNetworkState(mMobileNetwork2,
+                new LinkAddress("192.168.170.7/19"), null,
+                makeNetworkCapabilities(TRANSPORT_CELLULAR));
+        mPrivateAddressCoordinator.updateUpstreamPrefix(mobileUpstream);
+        mPrivateAddressCoordinator.updateUpstreamPrefix(mobileUpstream2);
+
+        // The conflict range are 128 ~ 159 and 159 ~ 191, so the address is 192.168.192.5/24.
+        final LinkAddress addr3 = requestDownstreamAddress(mHotspotIpServer,
+                true /* useLastAddress */);
+        assertEquals("Wrong prefix: ", new LinkAddress("192.168.192.5/24"), addr3);
+        final UpstreamNetworkState mobileUpstream3 = buildUpstreamNetworkState(mMobileNetwork3,
+                new LinkAddress("192.168.188.133/17"), null,
+                makeNetworkCapabilities(TRANSPORT_CELLULAR));
+        mPrivateAddressCoordinator.updateUpstreamPrefix(mobileUpstream3);
+
+        // Conflict range: 128 ~ 255. The next available address is 192.168.0.5 because
+        // 192.168.134/24 ~ 192.168.255.255/24 is not available.
+        final LinkAddress addr4 = requestDownstreamAddress(mHotspotIpServer,
+                true /* useLastAddress */);
+        assertEquals("Wrong prefix: ", new LinkAddress("192.168.0.5/24"), addr4);
+        final UpstreamNetworkState mobileUpstream4 = buildUpstreamNetworkState(mMobileNetwork4,
+                new LinkAddress("192.168.3.59/21"), null,
+                makeNetworkCapabilities(TRANSPORT_CELLULAR));
+        mPrivateAddressCoordinator.updateUpstreamPrefix(mobileUpstream4);
+
+        // Conflict ranges: 128 ~ 255 and 0 ~ 7, so the address is 192.168.8.5/24.
+        final LinkAddress addr5 = requestDownstreamAddress(mHotspotIpServer,
+                true /* useLastAddress */);
+        assertEquals("Wrong prefix: ", new LinkAddress("192.168.8.5/24"), addr5);
+        final UpstreamNetworkState mobileUpstream5 = buildUpstreamNetworkState(mMobileNetwork5,
+                new LinkAddress("192.168.68.43/21"), null,
+                makeNetworkCapabilities(TRANSPORT_CELLULAR));
+        mPrivateAddressCoordinator.updateUpstreamPrefix(mobileUpstream5);
+
+        // Update an upstream that does *not* conflict, check whether return the same address
+        // 192.168.5/24.
+        final LinkAddress addr6 = requestDownstreamAddress(mHotspotIpServer,
+                true /* useLastAddress */);
+        assertEquals("Wrong prefix: ", new LinkAddress("192.168.8.5/24"), addr6);
+        final UpstreamNetworkState mobileUpstream6 = buildUpstreamNetworkState(mMobileNetwork6,
+                new LinkAddress("192.168.10.97/21"), null,
+                makeNetworkCapabilities(TRANSPORT_CELLULAR));
+        mPrivateAddressCoordinator.updateUpstreamPrefix(mobileUpstream6);
+
+        // Conflict ranges: 0 ~ 15 and 128 ~ 255, so the address is 192.168.16.5/24.
+        final LinkAddress addr7 = requestDownstreamAddress(mHotspotIpServer,
+                true /* useLastAddress */);
+        assertEquals("Wrong prefix: ", new LinkAddress("192.168.16.5/24"), addr7);
+        final UpstreamNetworkState mobileUpstream7 = buildUpstreamNetworkState(mMobileNetwork6,
+                new LinkAddress("192.168.0.0/17"), null,
+                makeNetworkCapabilities(TRANSPORT_CELLULAR));
+        mPrivateAddressCoordinator.updateUpstreamPrefix(mobileUpstream7);
+
+        // Choose prefix from next range(172.16.0.0/12) when no available prefix in 192.168.0.0/16.
+        final LinkAddress addr8 = requestDownstreamAddress(mHotspotIpServer,
+                true /* useLastAddress */);
+        assertEquals("Wrong prefix: ", new LinkAddress("172.16.134.5/24"), addr8);
+    }
+
+    @Test
+    public void testChoosePrefixFromDifferentRanges() throws Exception {
+        final int randomAddress = 0x1f2b2a; // 31.43.42
+        when(mPrivateAddressCoordinator.getRandomInt()).thenReturn(randomAddress);
+        final LinkAddress classC1 = requestDownstreamAddress(mHotspotIpServer,
+                true /* useLastAddress */);
+        // Check whether return address is prefix 192.168.0.0/16 + subAddress 0.0.43.42.
+        assertEquals("Wrong prefix: ", new LinkAddress("192.168.43.42/24"), classC1);
+        final UpstreamNetworkState wifiUpstream = buildUpstreamNetworkState(mWifiNetwork,
+                new LinkAddress("192.168.88.23/17"), null,
+                makeNetworkCapabilities(TRANSPORT_WIFI));
+        mPrivateAddressCoordinator.updateUpstreamPrefix(wifiUpstream);
+        verifyNotifyConflictAndRelease(mHotspotIpServer);
+
+        // Check whether return address is next address of prefix 192.168.128.0/17.
+        final LinkAddress classC2 = requestDownstreamAddress(mHotspotIpServer,
+                true /* useLastAddress */);
+        assertEquals("Wrong prefix: ", new LinkAddress("192.168.128.42/24"), classC2);
+        final UpstreamNetworkState mobileUpstream = buildUpstreamNetworkState(mMobileNetwork,
+                new LinkAddress("192.1.2.3/8"), null,
+                makeNetworkCapabilities(TRANSPORT_CELLULAR));
+        mPrivateAddressCoordinator.updateUpstreamPrefix(mobileUpstream);
+        verifyNotifyConflictAndRelease(mHotspotIpServer);
+
+        // Check whether return address is under prefix 172.16.0.0/12.
+        final LinkAddress classB1 = requestDownstreamAddress(mHotspotIpServer,
+                true /* useLastAddress */);
+        assertEquals("Wrong prefix: ", new LinkAddress("172.31.43.42/24"), classB1);
+        final UpstreamNetworkState mobileUpstream2 = buildUpstreamNetworkState(mMobileNetwork2,
+                new LinkAddress("172.28.123.100/14"), null,
+                makeNetworkCapabilities(TRANSPORT_CELLULAR));
+        mPrivateAddressCoordinator.updateUpstreamPrefix(mobileUpstream2);
+        verifyNotifyConflictAndRelease(mHotspotIpServer);
+
+        // 172.28.0.0 ~ 172.31.255.255 is not available.
+        // Check whether return address is next address of prefix 172.16.0.0/14.
+        final LinkAddress classB2 = requestDownstreamAddress(mHotspotIpServer,
+                true /* useLastAddress */);
+        assertEquals("Wrong prefix: ", new LinkAddress("172.16.0.42/24"), classB2);
+
+        // Check whether new downstream is next address of address 172.16.0.42/24.
+        final LinkAddress classB3 = requestDownstreamAddress(mUsbIpServer,
+                true /* useLastAddress */);
+        assertEquals("Wrong prefix: ", new LinkAddress("172.16.1.42/24"), classB3);
+        final UpstreamNetworkState mobileUpstream3 = buildUpstreamNetworkState(mMobileNetwork3,
+                new LinkAddress("172.16.0.1/24"), null,
+                makeNetworkCapabilities(TRANSPORT_CELLULAR));
+        mPrivateAddressCoordinator.updateUpstreamPrefix(mobileUpstream3);
+        verifyNotifyConflictAndRelease(mHotspotIpServer);
+        verify(mUsbIpServer, never()).sendMessage(IpServer.CMD_NOTIFY_PREFIX_CONFLICT);
+
+        // Check whether return address is next address of prefix 172.16.1.42/24.
+        final LinkAddress classB4 = requestDownstreamAddress(mHotspotIpServer,
+                true /* useLastAddress */);
+        assertEquals("Wrong prefix: ", new LinkAddress("172.16.2.42/24"), classB4);
+        final UpstreamNetworkState mobileUpstream4 = buildUpstreamNetworkState(mMobileNetwork4,
+                new LinkAddress("172.16.0.1/13"), null,
+                makeNetworkCapabilities(TRANSPORT_CELLULAR));
+        mPrivateAddressCoordinator.updateUpstreamPrefix(mobileUpstream4);
+        verifyNotifyConflictAndRelease(mHotspotIpServer);
+        verifyNotifyConflictAndRelease(mUsbIpServer);
+
+        // Check whether return address is next address of prefix 172.16.0.1/13.
+        final LinkAddress classB5 = requestDownstreamAddress(mHotspotIpServer,
+                true /* useLastAddress */);
+        assertEquals("Wrong prefix: ", new LinkAddress("172.24.0.42/24"), classB5);
+        // Check whether return address is next address of prefix 172.24.0.42/24.
+        final LinkAddress classB6 = requestDownstreamAddress(mUsbIpServer,
+                true /* useLastAddress */);
+        assertEquals("Wrong prefix: ", new LinkAddress("172.24.1.42/24"), classB6);
+        final UpstreamNetworkState mobileUpstream5 = buildUpstreamNetworkState(mMobileNetwork5,
+                new LinkAddress("172.24.0.1/12"), null,
+                makeNetworkCapabilities(TRANSPORT_CELLULAR));
+        mPrivateAddressCoordinator.updateUpstreamPrefix(mobileUpstream5);
+        verifyNotifyConflictAndRelease(mHotspotIpServer);
+        verifyNotifyConflictAndRelease(mUsbIpServer);
+
+        // Check whether return address is prefix 10.0.0.0/8 + subAddress 0.31.43.42.
+        final LinkAddress classA1 = requestDownstreamAddress(mHotspotIpServer,
+                true /* useLastAddress */);
+        assertEquals("Wrong prefix: ", new LinkAddress("10.31.43.42/24"), classA1);
+        // Check whether new downstream is next address of address 10.31.43.42/24.
+        final LinkAddress classA2 = requestDownstreamAddress(mUsbIpServer,
+                true /* useLastAddress */);
+        assertEquals("Wrong prefix: ", new LinkAddress("10.31.44.42/24"), classA2);
+    }
+
+    private void verifyNotifyConflictAndRelease(final IpServer ipServer) throws Exception {
+        verify(ipServer).sendMessage(IpServer.CMD_NOTIFY_PREFIX_CONFLICT);
+        mPrivateAddressCoordinator.releaseDownstream(ipServer);
+        reset(ipServer);
+        setUpIpServers();
+    }
+
+    private int getSubAddress(final byte... ipv4Address) {
+        assertEquals(4, ipv4Address.length);
+
+        int subnet = Byte.toUnsignedInt(ipv4Address[2]);
+        return (subnet << 8) + ipv4Address[3];
+    }
+
+    private void assertReseveredWifiP2pPrefix() throws Exception {
+        LinkAddress address = requestDownstreamAddress(mHotspotIpServer,
+                true /* useLastAddress */);
+        final IpPrefix hotspotPrefix = asIpPrefix(address);
+        final IpPrefix legacyWifiP2pPrefix = asIpPrefix(mLegacyWifiP2pAddress);
+        assertNotEquals(legacyWifiP2pPrefix, hotspotPrefix);
+        mPrivateAddressCoordinator.releaseDownstream(mHotspotIpServer);
+    }
+
+    @Test
+    public void testEnableLegacyWifiP2PAddress() throws Exception {
+        when(mPrivateAddressCoordinator.getRandomInt()).thenReturn(
+                getSubAddress(mLegacyWifiP2pAddress.getAddress().getAddress()));
+        // No matter #shouldEnableWifiP2pDedicatedIp() is enabled or not, legacy wifi p2p prefix
+        // is resevered.
+        assertReseveredWifiP2pPrefix();
+
+        when(mConfig.shouldEnableWifiP2pDedicatedIp()).thenReturn(true);
+        assertReseveredWifiP2pPrefix();
+
+        // If #shouldEnableWifiP2pDedicatedIp() is enabled, wifi P2P gets the configured address.
+        LinkAddress address = requestDownstreamAddress(mWifiP2pIpServer,
+                true /* useLastAddress */);
+        assertEquals(mLegacyWifiP2pAddress, address);
+        mPrivateAddressCoordinator.releaseDownstream(mWifiP2pIpServer);
+    }
+}
diff --git a/Tethering/tests/unit/src/com/android/networkstack/tethering/TetheringConfigurationTest.java b/Tethering/tests/unit/src/com/android/networkstack/tethering/TetheringConfigurationTest.java
new file mode 100644
index 0000000..237e2c2
--- /dev/null
+++ b/Tethering/tests/unit/src/com/android/networkstack/tethering/TetheringConfigurationTest.java
@@ -0,0 +1,458 @@
+/*
+ * Copyright (C) 2017 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.android.networkstack.tethering;
+
+import static android.net.ConnectivityManager.TYPE_ETHERNET;
+import static android.net.ConnectivityManager.TYPE_MOBILE;
+import static android.net.ConnectivityManager.TYPE_MOBILE_DUN;
+import static android.net.ConnectivityManager.TYPE_MOBILE_HIPRI;
+import static android.net.ConnectivityManager.TYPE_WIFI;
+import static android.provider.DeviceConfig.NAMESPACE_CONNECTIVITY;
+import static android.telephony.SubscriptionManager.INVALID_SUBSCRIPTION_ID;
+
+import static com.android.dx.mockito.inline.extended.ExtendedMockito.doReturn;
+import static com.android.dx.mockito.inline.extended.ExtendedMockito.mockitoSession;
+
+import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertFalse;
+import static org.junit.Assert.assertTrue;
+import static org.mockito.Matchers.eq;
+import static org.mockito.Mockito.when;
+
+import android.content.Context;
+import android.content.res.Resources;
+import android.net.util.SharedLog;
+import android.provider.DeviceConfig;
+import android.telephony.TelephonyManager;
+
+import androidx.test.filters.SmallTest;
+import androidx.test.runner.AndroidJUnit4;
+
+import com.android.internal.util.test.BroadcastInterceptingContext;
+
+import org.junit.After;
+import org.junit.Before;
+import org.junit.Test;
+import org.junit.runner.RunWith;
+import org.mockito.Mock;
+import org.mockito.MockitoSession;
+import org.mockito.quality.Strictness;
+
+import java.util.Arrays;
+import java.util.Iterator;
+
+@RunWith(AndroidJUnit4.class)
+@SmallTest
+public class TetheringConfigurationTest {
+    private final SharedLog mLog = new SharedLog("TetheringConfigurationTest");
+
+    private static final String[] PROVISIONING_APP_NAME = {"some", "app"};
+    private static final String PROVISIONING_NO_UI_APP_NAME = "no_ui_app";
+    private static final String PROVISIONING_APP_RESPONSE = "app_response";
+    @Mock private Context mContext;
+    @Mock private TelephonyManager mTelephonyManager;
+    @Mock private Resources mResources;
+    @Mock private Resources mResourcesForSubId;
+    private Context mMockContext;
+    private boolean mHasTelephonyManager;
+    private boolean mEnableLegacyDhcpServer;
+    private MockitoSession mMockingSession;
+
+    private class MockTetheringConfiguration extends TetheringConfiguration {
+        MockTetheringConfiguration(Context ctx, SharedLog log, int id) {
+            super(ctx, log, id);
+        }
+
+        @Override
+        protected Resources getResourcesForSubIdWrapper(Context ctx, int subId) {
+            return mResourcesForSubId;
+        }
+    }
+
+    private class MockContext extends BroadcastInterceptingContext {
+        MockContext(Context base) {
+            super(base);
+        }
+
+        @Override
+        public Resources getResources() {
+            return mResources;
+        }
+
+        @Override
+        public Object getSystemService(String name) {
+            if (Context.TELEPHONY_SERVICE.equals(name)) {
+                return mHasTelephonyManager ? mTelephonyManager : null;
+            }
+            return super.getSystemService(name);
+        }
+    }
+
+    @Before
+    public void setUp() throws Exception {
+        // TODO: use a dependencies class instead of mock statics.
+        mMockingSession = mockitoSession()
+                .initMocks(this)
+                .mockStatic(DeviceConfig.class)
+                .strictness(Strictness.WARN)
+                .startMocking();
+        doReturn(null).when(
+                () -> DeviceConfig.getProperty(eq(NAMESPACE_CONNECTIVITY),
+                eq(TetheringConfiguration.TETHER_ENABLE_LEGACY_DHCP_SERVER)));
+
+        when(mResources.getStringArray(R.array.config_tether_dhcp_range)).thenReturn(
+                new String[0]);
+        when(mResources.getInteger(R.integer.config_tether_offload_poll_interval)).thenReturn(
+                TetheringConfiguration.DEFAULT_TETHER_OFFLOAD_POLL_INTERVAL_MS);
+        when(mResources.getStringArray(R.array.config_tether_usb_regexs)).thenReturn(new String[0]);
+        when(mResources.getStringArray(R.array.config_tether_wifi_regexs))
+                .thenReturn(new String[]{ "test_wlan\\d" });
+        when(mResources.getStringArray(R.array.config_tether_bluetooth_regexs)).thenReturn(
+                new String[0]);
+        when(mResources.getIntArray(R.array.config_tether_upstream_types)).thenReturn(new int[0]);
+        when(mResources.getStringArray(R.array.config_mobile_hotspot_provision_app))
+                .thenReturn(new String[0]);
+        when(mResources.getBoolean(R.bool.config_tether_enable_legacy_dhcp_server)).thenReturn(
+                false);
+        when(mResources.getBoolean(R.bool.config_tether_enable_legacy_wifi_p2p_dedicated_ip))
+                .thenReturn(false);
+        initializeBpfOffloadConfiguration(true, null /* unset */);
+        initEnableSelectAllPrefixRangeFlag(null /* unset */);
+
+        mHasTelephonyManager = true;
+        mMockContext = new MockContext(mContext);
+        mEnableLegacyDhcpServer = false;
+    }
+
+    @After
+    public void tearDown() throws Exception {
+        mMockingSession.finishMocking();
+    }
+
+    private TetheringConfiguration getTetheringConfiguration(int... legacyTetherUpstreamTypes) {
+        when(mResources.getIntArray(R.array.config_tether_upstream_types)).thenReturn(
+                legacyTetherUpstreamTypes);
+        return new TetheringConfiguration(mMockContext, mLog, INVALID_SUBSCRIPTION_ID);
+    }
+
+    @Test
+    public void testNoTelephonyManagerMeansNoDun() {
+        mHasTelephonyManager = false;
+        final TetheringConfiguration cfg = getTetheringConfiguration(
+                new int[]{TYPE_MOBILE_DUN, TYPE_WIFI});
+        assertFalse(cfg.isDunRequired);
+        assertFalse(cfg.preferredUpstreamIfaceTypes.contains(TYPE_MOBILE_DUN));
+        // Just to prove we haven't clobbered Wi-Fi:
+        assertTrue(cfg.preferredUpstreamIfaceTypes.contains(TYPE_WIFI));
+    }
+
+    @Test
+    public void testDunFromTelephonyManagerMeansDun() {
+        when(mTelephonyManager.isTetheringApnRequired()).thenReturn(true);
+
+        final TetheringConfiguration cfgWifi = getTetheringConfiguration(TYPE_WIFI);
+        final TetheringConfiguration cfgMobileWifiHipri = getTetheringConfiguration(
+                TYPE_MOBILE, TYPE_WIFI, TYPE_MOBILE_HIPRI);
+        final TetheringConfiguration cfgWifiDun = getTetheringConfiguration(
+                TYPE_WIFI, TYPE_MOBILE_DUN);
+        final TetheringConfiguration cfgMobileWifiHipriDun = getTetheringConfiguration(
+                TYPE_MOBILE, TYPE_WIFI, TYPE_MOBILE_HIPRI, TYPE_MOBILE_DUN);
+
+        for (TetheringConfiguration cfg : Arrays.asList(cfgWifi, cfgMobileWifiHipri,
+                cfgWifiDun, cfgMobileWifiHipriDun)) {
+            String msg = "config=" + cfg.toString();
+            assertTrue(msg, cfg.isDunRequired);
+            assertTrue(msg, cfg.preferredUpstreamIfaceTypes.contains(TYPE_MOBILE_DUN));
+            assertFalse(msg, cfg.preferredUpstreamIfaceTypes.contains(TYPE_MOBILE));
+            assertFalse(msg, cfg.preferredUpstreamIfaceTypes.contains(TYPE_MOBILE_HIPRI));
+            // Just to prove we haven't clobbered Wi-Fi:
+            assertTrue(msg, cfg.preferredUpstreamIfaceTypes.contains(TYPE_WIFI));
+        }
+    }
+
+    @Test
+    public void testDunNotRequiredFromTelephonyManagerMeansNoDun() {
+        when(mTelephonyManager.isTetheringApnRequired()).thenReturn(false);
+
+        final TetheringConfiguration cfgWifi = getTetheringConfiguration(TYPE_WIFI);
+        final TetheringConfiguration cfgMobileWifiHipri = getTetheringConfiguration(
+                TYPE_MOBILE, TYPE_WIFI, TYPE_MOBILE_HIPRI);
+        final TetheringConfiguration cfgWifiDun = getTetheringConfiguration(
+                TYPE_WIFI, TYPE_MOBILE_DUN);
+        final TetheringConfiguration cfgWifiMobile = getTetheringConfiguration(
+                TYPE_WIFI, TYPE_MOBILE);
+        final TetheringConfiguration cfgWifiHipri = getTetheringConfiguration(
+                TYPE_WIFI, TYPE_MOBILE_HIPRI);
+        final TetheringConfiguration cfgMobileWifiHipriDun = getTetheringConfiguration(
+                TYPE_MOBILE, TYPE_WIFI, TYPE_MOBILE_HIPRI, TYPE_MOBILE_DUN);
+
+        String msg;
+        // TYPE_MOBILE_DUN should be present in none of the combinations.
+        // TYPE_WIFI should not be affected.
+        for (TetheringConfiguration cfg : Arrays.asList(cfgWifi, cfgMobileWifiHipri, cfgWifiDun,
+                cfgWifiMobile, cfgWifiHipri, cfgMobileWifiHipriDun)) {
+            msg = "config=" + cfg.toString();
+            assertFalse(msg, cfg.isDunRequired);
+            assertFalse(msg, cfg.preferredUpstreamIfaceTypes.contains(TYPE_MOBILE_DUN));
+            assertTrue(msg, cfg.preferredUpstreamIfaceTypes.contains(TYPE_WIFI));
+        }
+
+        for (TetheringConfiguration cfg : Arrays.asList(cfgWifi, cfgMobileWifiHipri, cfgWifiDun,
+                cfgMobileWifiHipriDun)) {
+            msg = "config=" + cfg.toString();
+            assertTrue(msg, cfg.preferredUpstreamIfaceTypes.contains(TYPE_MOBILE));
+            assertTrue(msg, cfg.preferredUpstreamIfaceTypes.contains(TYPE_MOBILE_HIPRI));
+        }
+        msg = "config=" + cfgWifiMobile.toString();
+        assertTrue(msg, cfgWifiMobile.preferredUpstreamIfaceTypes.contains(TYPE_MOBILE));
+        assertFalse(msg, cfgWifiMobile.preferredUpstreamIfaceTypes.contains(TYPE_MOBILE_HIPRI));
+        msg = "config=" + cfgWifiHipri.toString();
+        assertFalse(msg, cfgWifiHipri.preferredUpstreamIfaceTypes.contains(TYPE_MOBILE));
+        assertTrue(msg, cfgWifiHipri.preferredUpstreamIfaceTypes.contains(TYPE_MOBILE_HIPRI));
+
+    }
+
+    @Test
+    public void testNoDefinedUpstreamTypesAddsEthernet() {
+        when(mResources.getIntArray(R.array.config_tether_upstream_types)).thenReturn(new int[]{});
+        when(mTelephonyManager.isTetheringApnRequired()).thenReturn(false);
+
+        final TetheringConfiguration cfg = new TetheringConfiguration(
+                mMockContext, mLog, INVALID_SUBSCRIPTION_ID);
+        final Iterator<Integer> upstreamIterator = cfg.preferredUpstreamIfaceTypes.iterator();
+        assertTrue(upstreamIterator.hasNext());
+        assertEquals(TYPE_ETHERNET, upstreamIterator.next().intValue());
+        // The following is because the code always adds some kind of mobile
+        // upstream, be it DUN or, in this case where DUN is NOT required,
+        // make sure there is at least one of MOBILE or HIPRI. With the empty
+        // list of the configuration in this test, it will always add both
+        // MOBILE and HIPRI, in that order.
+        assertTrue(upstreamIterator.hasNext());
+        assertEquals(TYPE_MOBILE, upstreamIterator.next().intValue());
+        assertTrue(upstreamIterator.hasNext());
+        assertEquals(TYPE_MOBILE_HIPRI, upstreamIterator.next().intValue());
+        assertFalse(upstreamIterator.hasNext());
+    }
+
+    @Test
+    public void testDefinedUpstreamTypesSansEthernetAddsEthernet() {
+        when(mResources.getIntArray(R.array.config_tether_upstream_types)).thenReturn(
+                new int[]{TYPE_WIFI, TYPE_MOBILE_HIPRI});
+        when(mTelephonyManager.isTetheringApnRequired()).thenReturn(false);
+
+        final TetheringConfiguration cfg = new TetheringConfiguration(
+                mMockContext, mLog, INVALID_SUBSCRIPTION_ID);
+        final Iterator<Integer> upstreamIterator = cfg.preferredUpstreamIfaceTypes.iterator();
+        assertTrue(upstreamIterator.hasNext());
+        assertEquals(TYPE_ETHERNET, upstreamIterator.next().intValue());
+        assertTrue(upstreamIterator.hasNext());
+        assertEquals(TYPE_WIFI, upstreamIterator.next().intValue());
+        assertTrue(upstreamIterator.hasNext());
+        assertEquals(TYPE_MOBILE_HIPRI, upstreamIterator.next().intValue());
+        assertFalse(upstreamIterator.hasNext());
+    }
+
+    @Test
+    public void testDefinedUpstreamTypesWithEthernetDoesNotAddEthernet() {
+        when(mResources.getIntArray(R.array.config_tether_upstream_types))
+                .thenReturn(new int[]{TYPE_WIFI, TYPE_ETHERNET, TYPE_MOBILE_HIPRI});
+        when(mTelephonyManager.isTetheringApnRequired()).thenReturn(false);
+
+        final TetheringConfiguration cfg = new TetheringConfiguration(
+                mMockContext, mLog, INVALID_SUBSCRIPTION_ID);
+        final Iterator<Integer> upstreamIterator = cfg.preferredUpstreamIfaceTypes.iterator();
+        assertTrue(upstreamIterator.hasNext());
+        assertEquals(TYPE_WIFI, upstreamIterator.next().intValue());
+        assertTrue(upstreamIterator.hasNext());
+        assertEquals(TYPE_ETHERNET, upstreamIterator.next().intValue());
+        assertTrue(upstreamIterator.hasNext());
+        assertEquals(TYPE_MOBILE_HIPRI, upstreamIterator.next().intValue());
+        assertFalse(upstreamIterator.hasNext());
+    }
+
+    private void initializeBpfOffloadConfiguration(
+            final boolean fromRes, final String fromDevConfig) {
+        when(mResources.getBoolean(R.bool.config_tether_enable_bpf_offload)).thenReturn(fromRes);
+        doReturn(fromDevConfig).when(
+                () -> DeviceConfig.getProperty(eq(NAMESPACE_CONNECTIVITY),
+                eq(TetheringConfiguration.OVERRIDE_TETHER_ENABLE_BPF_OFFLOAD)));
+    }
+
+    @Test
+    public void testBpfOffloadEnabledByResource() {
+        initializeBpfOffloadConfiguration(true, null /* unset */);
+        final TetheringConfiguration enableByRes =
+                new TetheringConfiguration(mMockContext, mLog, INVALID_SUBSCRIPTION_ID);
+        assertTrue(enableByRes.isBpfOffloadEnabled());
+    }
+
+    @Test
+    public void testBpfOffloadEnabledByDeviceConfigOverride() {
+        for (boolean res : new boolean[]{true, false}) {
+            initializeBpfOffloadConfiguration(res, "true");
+            final TetheringConfiguration enableByDevConOverride =
+                    new TetheringConfiguration(mMockContext, mLog, INVALID_SUBSCRIPTION_ID);
+            assertTrue(enableByDevConOverride.isBpfOffloadEnabled());
+        }
+    }
+
+    @Test
+    public void testBpfOffloadDisabledByResource() {
+        initializeBpfOffloadConfiguration(false, null /* unset */);
+        final TetheringConfiguration disableByRes =
+                new TetheringConfiguration(mMockContext, mLog, INVALID_SUBSCRIPTION_ID);
+        assertFalse(disableByRes.isBpfOffloadEnabled());
+    }
+
+    @Test
+    public void testBpfOffloadDisabledByDeviceConfigOverride() {
+        for (boolean res : new boolean[]{true, false}) {
+            initializeBpfOffloadConfiguration(res, "false");
+            final TetheringConfiguration disableByDevConOverride =
+                    new TetheringConfiguration(mMockContext, mLog, INVALID_SUBSCRIPTION_ID);
+            assertFalse(disableByDevConOverride.isBpfOffloadEnabled());
+        }
+    }
+
+    @Test
+    public void testNewDhcpServerDisabled() {
+        when(mResources.getBoolean(R.bool.config_tether_enable_legacy_dhcp_server)).thenReturn(
+                true);
+        doReturn("false").when(
+                () -> DeviceConfig.getProperty(eq(NAMESPACE_CONNECTIVITY),
+                eq(TetheringConfiguration.TETHER_ENABLE_LEGACY_DHCP_SERVER)));
+
+        final TetheringConfiguration enableByRes =
+                new TetheringConfiguration(mMockContext, mLog, INVALID_SUBSCRIPTION_ID);
+        assertTrue(enableByRes.enableLegacyDhcpServer);
+
+        when(mResources.getBoolean(R.bool.config_tether_enable_legacy_dhcp_server)).thenReturn(
+                false);
+        doReturn("true").when(
+                () -> DeviceConfig.getProperty(eq(NAMESPACE_CONNECTIVITY),
+                eq(TetheringConfiguration.TETHER_ENABLE_LEGACY_DHCP_SERVER)));
+
+        final TetheringConfiguration enableByDevConfig =
+                new TetheringConfiguration(mMockContext, mLog, INVALID_SUBSCRIPTION_ID);
+        assertTrue(enableByDevConfig.enableLegacyDhcpServer);
+    }
+
+    @Test
+    public void testNewDhcpServerEnabled() {
+        when(mResources.getBoolean(R.bool.config_tether_enable_legacy_dhcp_server)).thenReturn(
+                false);
+        doReturn("false").when(
+                () -> DeviceConfig.getProperty(eq(NAMESPACE_CONNECTIVITY),
+                eq(TetheringConfiguration.TETHER_ENABLE_LEGACY_DHCP_SERVER)));
+
+        final TetheringConfiguration cfg =
+                new TetheringConfiguration(mMockContext, mLog, INVALID_SUBSCRIPTION_ID);
+
+        assertFalse(cfg.enableLegacyDhcpServer);
+    }
+
+    @Test
+    public void testOffloadIntervalByResource() {
+        final TetheringConfiguration intervalByDefault =
+                new TetheringConfiguration(mMockContext, mLog, INVALID_SUBSCRIPTION_ID);
+        assertEquals(TetheringConfiguration.DEFAULT_TETHER_OFFLOAD_POLL_INTERVAL_MS,
+                intervalByDefault.getOffloadPollInterval());
+
+        final int[] testOverrides = {0, 3000, -1};
+        for (final int override : testOverrides) {
+            when(mResources.getInteger(R.integer.config_tether_offload_poll_interval)).thenReturn(
+                    override);
+            final TetheringConfiguration overrideByRes =
+                    new TetheringConfiguration(mMockContext, mLog, INVALID_SUBSCRIPTION_ID);
+            assertEquals(override, overrideByRes.getOffloadPollInterval());
+        }
+    }
+
+    @Test
+    public void testGetResourcesBySubId() {
+        setUpResourceForSubId();
+        final TetheringConfiguration cfg = new TetheringConfiguration(
+                mMockContext, mLog, INVALID_SUBSCRIPTION_ID);
+        assertTrue(cfg.provisioningApp.length == 0);
+        final int anyValidSubId = 1;
+        final MockTetheringConfiguration mockCfg =
+                new MockTetheringConfiguration(mMockContext, mLog, anyValidSubId);
+        assertEquals(mockCfg.provisioningApp[0], PROVISIONING_APP_NAME[0]);
+        assertEquals(mockCfg.provisioningApp[1], PROVISIONING_APP_NAME[1]);
+        assertEquals(mockCfg.provisioningAppNoUi, PROVISIONING_NO_UI_APP_NAME);
+        assertEquals(mockCfg.provisioningResponse, PROVISIONING_APP_RESPONSE);
+    }
+
+    private void setUpResourceForSubId() {
+        when(mResourcesForSubId.getStringArray(
+                R.array.config_tether_dhcp_range)).thenReturn(new String[0]);
+        when(mResourcesForSubId.getStringArray(
+                R.array.config_tether_usb_regexs)).thenReturn(new String[0]);
+        when(mResourcesForSubId.getStringArray(
+                R.array.config_tether_wifi_regexs)).thenReturn(new String[]{ "test_wlan\\d" });
+        when(mResourcesForSubId.getStringArray(
+                R.array.config_tether_bluetooth_regexs)).thenReturn(new String[0]);
+        when(mResourcesForSubId.getIntArray(R.array.config_tether_upstream_types)).thenReturn(
+                new int[0]);
+        when(mResourcesForSubId.getStringArray(
+                R.array.config_mobile_hotspot_provision_app)).thenReturn(PROVISIONING_APP_NAME);
+        when(mResourcesForSubId.getString(R.string.config_mobile_hotspot_provision_app_no_ui))
+                .thenReturn(PROVISIONING_NO_UI_APP_NAME);
+        when(mResourcesForSubId.getString(
+                R.string.config_mobile_hotspot_provision_response)).thenReturn(
+                PROVISIONING_APP_RESPONSE);
+    }
+
+    @Test
+    public void testEnableLegacyWifiP2PAddress() throws Exception {
+        final TetheringConfiguration defaultCfg = new TetheringConfiguration(
+                mMockContext, mLog, INVALID_SUBSCRIPTION_ID);
+        assertFalse(defaultCfg.shouldEnableWifiP2pDedicatedIp());
+
+        when(mResources.getBoolean(R.bool.config_tether_enable_legacy_wifi_p2p_dedicated_ip))
+                .thenReturn(true);
+        final TetheringConfiguration testCfg = new TetheringConfiguration(
+                mMockContext, mLog, INVALID_SUBSCRIPTION_ID);
+        assertTrue(testCfg.shouldEnableWifiP2pDedicatedIp());
+    }
+
+    private void initEnableSelectAllPrefixRangeFlag(final String value) {
+        doReturn(value).when(
+                () -> DeviceConfig.getProperty(eq(NAMESPACE_CONNECTIVITY),
+                eq(TetheringConfiguration.TETHER_ENABLE_SELECT_ALL_PREFIX_RANGES)));
+    }
+
+    @Test
+    public void testSelectAllPrefixRangeFlag() throws Exception {
+        // Test default value.
+        final TetheringConfiguration defaultCfg = new TetheringConfiguration(
+                mMockContext, mLog, INVALID_SUBSCRIPTION_ID);
+        assertTrue(defaultCfg.isSelectAllPrefixRangeEnabled());
+
+        // Test disable flag.
+        initEnableSelectAllPrefixRangeFlag("false");
+        final TetheringConfiguration testDisable = new TetheringConfiguration(
+                mMockContext, mLog, INVALID_SUBSCRIPTION_ID);
+        assertFalse(testDisable.isSelectAllPrefixRangeEnabled());
+
+        // Test enable flag.
+        initEnableSelectAllPrefixRangeFlag("true");
+        final TetheringConfiguration testEnable = new TetheringConfiguration(
+                mMockContext, mLog, INVALID_SUBSCRIPTION_ID);
+        assertTrue(testEnable.isSelectAllPrefixRangeEnabled());
+    }
+}
diff --git a/Tethering/tests/unit/src/com/android/networkstack/tethering/TetheringNotificationUpdaterTest.kt b/Tethering/tests/unit/src/com/android/networkstack/tethering/TetheringNotificationUpdaterTest.kt
new file mode 100644
index 0000000..75c819b
--- /dev/null
+++ b/Tethering/tests/unit/src/com/android/networkstack/tethering/TetheringNotificationUpdaterTest.kt
@@ -0,0 +1,444 @@
+/*
+ * Copyright (C) 2020 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.android.networkstack.tethering
+
+import android.app.Notification
+import android.app.NotificationManager
+import android.app.PendingIntent
+import android.app.PendingIntent.FLAG_IMMUTABLE
+import android.content.Context
+import android.content.Intent
+import android.content.pm.ActivityInfo
+import android.content.pm.ApplicationInfo
+import android.content.pm.PackageManager
+import android.content.pm.ResolveInfo
+import android.content.res.Resources
+import android.net.ConnectivityManager.TETHERING_WIFI
+import android.net.NetworkCapabilities
+import android.net.NetworkCapabilities.NET_CAPABILITY_NOT_ROAMING
+import android.os.Handler
+import android.os.HandlerThread
+import android.os.Looper
+import android.os.UserHandle
+import android.provider.Settings
+import android.telephony.TelephonyManager
+import androidx.test.filters.SmallTest
+import androidx.test.platform.app.InstrumentationRegistry
+import androidx.test.runner.AndroidJUnit4
+import com.android.internal.util.test.BroadcastInterceptingContext
+import com.android.networkstack.tethering.TetheringNotificationUpdater.ACTION_DISABLE_TETHERING
+import com.android.networkstack.tethering.TetheringNotificationUpdater.DOWNSTREAM_NONE
+import com.android.networkstack.tethering.TetheringNotificationUpdater.EVENT_SHOW_NO_UPSTREAM
+import com.android.networkstack.tethering.TetheringNotificationUpdater.NO_UPSTREAM_NOTIFICATION_ID
+import com.android.networkstack.tethering.TetheringNotificationUpdater.RESTRICTED_NOTIFICATION_ID
+import com.android.networkstack.tethering.TetheringNotificationUpdater.ROAMING_NOTIFICATION_ID
+import com.android.networkstack.tethering.TetheringNotificationUpdater.VERIZON_CARRIER_ID
+import com.android.networkstack.tethering.TetheringNotificationUpdater.getSettingsPackageName
+import com.android.testutils.waitForIdle
+import org.junit.After
+import org.junit.Assert.assertEquals
+import org.junit.Assert.assertNotNull
+import org.junit.Assert.fail
+import org.junit.Before
+import org.junit.Test
+import org.junit.runner.RunWith
+import org.mockito.ArgumentCaptor
+import org.mockito.ArgumentMatchers.any
+import org.mockito.ArgumentMatchers.anyInt
+import org.mockito.ArgumentMatchers.eq
+import org.mockito.Mock
+import org.mockito.Mockito.doReturn
+import org.mockito.Mockito.mock
+import org.mockito.Mockito.never
+import org.mockito.Mockito.reset
+import org.mockito.Mockito.times
+import org.mockito.Mockito.verify
+import org.mockito.Mockito.verifyZeroInteractions
+import org.mockito.MockitoAnnotations
+
+const val TEST_SUBID = 1
+const val WIFI_MASK = 1 shl TETHERING_WIFI
+const val TEST_DISALLOW_TITLE = "Tether function is disallowed"
+const val TEST_DISALLOW_MESSAGE = "Please contact your admin"
+const val TEST_NO_UPSTREAM_TITLE = "Hotspot has no internet access"
+const val TEST_NO_UPSTREAM_MESSAGE = "Device cannot connect to internet."
+const val TEST_NO_UPSTREAM_BUTTON = "Turn off hotspot"
+const val TEST_ROAMING_TITLE = "Hotspot is on"
+const val TEST_ROAMING_MESSAGE = "Additional charges may apply while roaming."
+
+@RunWith(AndroidJUnit4::class)
+@SmallTest
+class TetheringNotificationUpdaterTest {
+    // lateinit used here for mocks as they need to be reinitialized between each test and the test
+    // should crash if they are used before being initialized.
+    @Mock private lateinit var mockContext: Context
+    @Mock private lateinit var notificationManager: NotificationManager
+    @Mock private lateinit var telephonyManager: TelephonyManager
+    @Mock private lateinit var testResources: Resources
+
+    // lateinit for these classes under test, as they should be reset to a different instance for
+    // every test but should always be initialized before use (or the test should crash).
+    private lateinit var context: TestContext
+    private lateinit var notificationUpdater: TetheringNotificationUpdater
+
+    // Initializing the following members depends on initializing some of the mocks and
+    // is more logically done in setup().
+    private lateinit var fakeTetheringThread: HandlerThread
+
+    private val ROAMING_CAPABILITIES = NetworkCapabilities()
+    private val HOME_CAPABILITIES = NetworkCapabilities().addCapability(NET_CAPABILITY_NOT_ROAMING)
+    private val NOTIFICATION_ICON_ID = R.drawable.stat_sys_tether_general
+    private val TIMEOUT_MS = 500L
+    private val ACTIVITY_PENDING_INTENT = 0
+    private val BROADCAST_PENDING_INTENT = 1
+
+    private inner class TestContext(c: Context) : BroadcastInterceptingContext(c) {
+        override fun createContextAsUser(user: UserHandle, flags: Int) =
+                if (user == UserHandle.ALL) mockContext else this
+        override fun getSystemService(name: String) =
+                if (name == Context.TELEPHONY_SERVICE) telephonyManager
+                else super.getSystemService(name)
+    }
+
+    private inner class WrappedNotificationUpdater(c: Context, looper: Looper)
+        : TetheringNotificationUpdater(c, looper) {
+        override fun getResourcesForSubId(c: Context, subId: Int) =
+                if (subId == TEST_SUBID) testResources else super.getResourcesForSubId(c, subId)
+    }
+
+    private fun setupResources() {
+        doReturn(5).`when`(testResources)
+                .getInteger(R.integer.delay_to_show_no_upstream_after_no_backhaul)
+        doReturn(true).`when`(testResources)
+                .getBoolean(R.bool.config_upstream_roaming_notification)
+        doReturn(TEST_DISALLOW_TITLE).`when`(testResources)
+                .getString(R.string.disable_tether_notification_title)
+        doReturn(TEST_DISALLOW_MESSAGE).`when`(testResources)
+                .getString(R.string.disable_tether_notification_message)
+        doReturn(TEST_NO_UPSTREAM_TITLE).`when`(testResources)
+                .getString(R.string.no_upstream_notification_title)
+        doReturn(TEST_NO_UPSTREAM_MESSAGE).`when`(testResources)
+                .getString(R.string.no_upstream_notification_message)
+        doReturn(TEST_NO_UPSTREAM_BUTTON).`when`(testResources)
+                .getString(R.string.no_upstream_notification_disable_button)
+        doReturn(TEST_ROAMING_TITLE).`when`(testResources)
+                .getString(R.string.upstream_roaming_notification_title)
+        doReturn(TEST_ROAMING_MESSAGE).`when`(testResources)
+                .getString(R.string.upstream_roaming_notification_message)
+    }
+
+    @Before
+    fun setUp() {
+        MockitoAnnotations.initMocks(this)
+        context = TestContext(InstrumentationRegistry.getInstrumentation().context)
+        doReturn(notificationManager).`when`(mockContext)
+                .getSystemService(Context.NOTIFICATION_SERVICE)
+        fakeTetheringThread = HandlerThread(this::class.java.simpleName)
+        fakeTetheringThread.start()
+        notificationUpdater = WrappedNotificationUpdater(context, fakeTetheringThread.looper)
+        setupResources()
+    }
+
+    @After
+    fun tearDown() {
+        fakeTetheringThread.quitSafely()
+    }
+
+    private fun verifyActivityPendingIntent(intent: Intent, flags: Int) {
+        // Use FLAG_NO_CREATE to verify whether PendingIntent has FLAG_IMMUTABLE flag(forcefully add
+        // the flag in creating arguments). If the described PendingIntent does not already exist,
+        // getActivity() will return null instead of PendingIntent object.
+        val pi = PendingIntent.getActivity(
+                context.createContextAsUser(UserHandle.CURRENT, 0 /* flags */),
+                0 /* requestCode */,
+                intent,
+                flags or FLAG_IMMUTABLE or PendingIntent.FLAG_NO_CREATE,
+                null /* options */)
+        assertNotNull("Activity PendingIntent with FLAG_IMMUTABLE does not exist.", pi)
+    }
+
+    private fun verifyBroadcastPendingIntent(intent: Intent, flags: Int) {
+        // Use FLAG_NO_CREATE to verify whether PendingIntent has FLAG_IMMUTABLE flag(forcefully add
+        // the flag in creating arguments). If the described PendingIntent does not already exist,
+        // getBroadcast() will return null instead of PendingIntent object.
+        val pi = PendingIntent.getBroadcast(
+                context.createContextAsUser(UserHandle.CURRENT, 0 /* flags */),
+                0 /* requestCode */,
+                intent,
+                flags or FLAG_IMMUTABLE or PendingIntent.FLAG_NO_CREATE)
+        assertNotNull("Broadcast PendingIntent with FLAG_IMMUTABLE does not exist.", pi)
+    }
+
+    private fun Notification.title() = this.extras.getString(Notification.EXTRA_TITLE)
+    private fun Notification.text() = this.extras.getString(Notification.EXTRA_TEXT)
+
+    private fun verifyNotification(
+        iconId: Int,
+        title: String,
+        text: String,
+        id: Int,
+        intentSenderType: Int,
+        intent: Intent,
+        flags: Int
+    ) {
+        verify(notificationManager, never()).cancel(any(), eq(id))
+
+        val notificationCaptor = ArgumentCaptor.forClass(Notification::class.java)
+        verify(notificationManager, times(1))
+                .notify(any(), eq(id), notificationCaptor.capture())
+
+        val notification = notificationCaptor.getValue()
+        assertEquals(iconId, notification.smallIcon.resId)
+        assertEquals(title, notification.title())
+        assertEquals(text, notification.text())
+
+        when (intentSenderType) {
+            ACTIVITY_PENDING_INTENT -> verifyActivityPendingIntent(intent, flags)
+            BROADCAST_PENDING_INTENT -> verifyBroadcastPendingIntent(intent, flags)
+        }
+
+        reset(notificationManager)
+    }
+
+    private fun verifyNotificationCancelled(
+        notificationIds: List<Int>,
+        resetAfterVerified: Boolean = true
+    ) {
+        notificationIds.forEach {
+            verify(notificationManager, times(1)).cancel(any(), eq(it))
+        }
+        if (resetAfterVerified) reset(notificationManager)
+    }
+
+    @Test
+    fun testRestrictedNotification() {
+        val settingsIntent = Intent(Settings.ACTION_TETHER_SETTINGS)
+                .setPackage(getSettingsPackageName(context.packageManager))
+                .addFlags(Intent.FLAG_ACTIVITY_NEW_TASK)
+
+        // Set test sub id.
+        notificationUpdater.onActiveDataSubscriptionIdChanged(TEST_SUBID)
+        verifyNotificationCancelled(listOf(NO_UPSTREAM_NOTIFICATION_ID, ROAMING_NOTIFICATION_ID))
+
+        // User restrictions on. Show restricted notification.
+        notificationUpdater.notifyTetheringDisabledByRestriction()
+        verifyNotification(NOTIFICATION_ICON_ID, TEST_DISALLOW_TITLE, TEST_DISALLOW_MESSAGE,
+                RESTRICTED_NOTIFICATION_ID, ACTIVITY_PENDING_INTENT, settingsIntent, FLAG_IMMUTABLE)
+
+        // User restrictions off. Clear notification.
+        notificationUpdater.tetheringRestrictionLifted()
+        verifyNotificationCancelled(listOf(RESTRICTED_NOTIFICATION_ID))
+
+        // No downstream.
+        notificationUpdater.onDownstreamChanged(DOWNSTREAM_NONE)
+        verifyZeroInteractions(notificationManager)
+
+        // User restrictions on again. Show restricted notification.
+        notificationUpdater.notifyTetheringDisabledByRestriction()
+        verifyNotification(NOTIFICATION_ICON_ID, TEST_DISALLOW_TITLE, TEST_DISALLOW_MESSAGE,
+                RESTRICTED_NOTIFICATION_ID, ACTIVITY_PENDING_INTENT, settingsIntent, FLAG_IMMUTABLE)
+    }
+
+    val MAX_BACKOFF_MS = 200L
+    /**
+     * Waits for all messages, including delayed ones, to be processed.
+     *
+     * This will wait until the handler has no more messages to be processed including
+     * delayed ones, or the timeout has expired. It uses an exponential backoff strategy
+     * to wait longer and longer to consume less CPU, with the max granularity being
+     * MAX_BACKOFF_MS.
+     *
+     * @return true if all messages have been processed including delayed ones, false if timeout
+     *
+     * TODO: Move this method to com.android.testutils.HandlerUtils.kt.
+     */
+    private fun Handler.waitForDelayedMessage(what: Int?, timeoutMs: Long) {
+        fun hasMatchingMessages() =
+                if (what == null) hasMessagesOrCallbacks() else hasMessages(what)
+        val expiry = System.currentTimeMillis() + timeoutMs
+        var delay = 5L
+        while (System.currentTimeMillis() < expiry && hasMatchingMessages()) {
+            // None of Handler, Looper, Message and MessageQueue expose any way to retrieve
+            // the time when the next (let alone the last) message will be processed, so
+            // short of examining the internals with reflection sleep() is the only solution.
+            Thread.sleep(delay)
+            delay = (delay * 2)
+                    .coerceAtMost(expiry - System.currentTimeMillis())
+                    .coerceAtMost(MAX_BACKOFF_MS)
+        }
+
+        val timeout = expiry - System.currentTimeMillis()
+        if (timeout <= 0) fail("Delayed message did not process yet after ${timeoutMs}ms")
+        waitForIdle(timeout)
+    }
+
+    @Test
+    fun testNoUpstreamNotification() {
+        val disableIntent = Intent(ACTION_DISABLE_TETHERING).setPackage(context.packageName)
+
+        // Set test sub id.
+        notificationUpdater.onActiveDataSubscriptionIdChanged(TEST_SUBID)
+        verifyNotificationCancelled(listOf(NO_UPSTREAM_NOTIFICATION_ID, ROAMING_NOTIFICATION_ID))
+
+        // Wifi downstream.
+        notificationUpdater.onDownstreamChanged(WIFI_MASK)
+        verifyNotificationCancelled(listOf(NO_UPSTREAM_NOTIFICATION_ID, ROAMING_NOTIFICATION_ID))
+
+        // There is no upstream. Show no upstream notification.
+        notificationUpdater.onUpstreamCapabilitiesChanged(null)
+        notificationUpdater.handler.waitForDelayedMessage(EVENT_SHOW_NO_UPSTREAM, TIMEOUT_MS)
+        verifyNotification(NOTIFICATION_ICON_ID, TEST_NO_UPSTREAM_TITLE, TEST_NO_UPSTREAM_MESSAGE,
+                NO_UPSTREAM_NOTIFICATION_ID, BROADCAST_PENDING_INTENT, disableIntent,
+                FLAG_IMMUTABLE)
+
+        // Same capabilities changed. Nothing happened.
+        notificationUpdater.onUpstreamCapabilitiesChanged(null)
+        verifyZeroInteractions(notificationManager)
+
+        // Upstream come back. Clear no upstream notification.
+        notificationUpdater.onUpstreamCapabilitiesChanged(HOME_CAPABILITIES)
+        verifyNotificationCancelled(listOf(NO_UPSTREAM_NOTIFICATION_ID))
+
+        // No upstream again. Show no upstream notification.
+        notificationUpdater.onUpstreamCapabilitiesChanged(null)
+        notificationUpdater.handler.waitForDelayedMessage(EVENT_SHOW_NO_UPSTREAM, TIMEOUT_MS)
+        verifyNotification(NOTIFICATION_ICON_ID, TEST_NO_UPSTREAM_TITLE, TEST_NO_UPSTREAM_MESSAGE,
+                NO_UPSTREAM_NOTIFICATION_ID, BROADCAST_PENDING_INTENT, disableIntent,
+                FLAG_IMMUTABLE)
+
+        // No downstream.
+        notificationUpdater.onDownstreamChanged(DOWNSTREAM_NONE)
+        verifyNotificationCancelled(listOf(NO_UPSTREAM_NOTIFICATION_ID, ROAMING_NOTIFICATION_ID))
+
+        // Wifi downstream and home capabilities.
+        notificationUpdater.onDownstreamChanged(WIFI_MASK)
+        notificationUpdater.onUpstreamCapabilitiesChanged(HOME_CAPABILITIES)
+        verifyNotificationCancelled(listOf(NO_UPSTREAM_NOTIFICATION_ID, ROAMING_NOTIFICATION_ID))
+
+        // Set R.integer.delay_to_show_no_upstream_after_no_backhaul to -1 and change to no upstream
+        // again. Don't put up no upstream notification.
+        doReturn(-1).`when`(testResources)
+                .getInteger(R.integer.delay_to_show_no_upstream_after_no_backhaul)
+        notificationUpdater.onUpstreamCapabilitiesChanged(null)
+        notificationUpdater.handler.waitForDelayedMessage(EVENT_SHOW_NO_UPSTREAM, TIMEOUT_MS)
+        verifyNotificationCancelled(listOf(NO_UPSTREAM_NOTIFICATION_ID))
+    }
+
+    @Test
+    fun testGetResourcesForSubId() {
+        doReturn(telephonyManager).`when`(telephonyManager).createForSubscriptionId(anyInt())
+        doReturn(1234).`when`(telephonyManager).getSimCarrierId()
+        doReturn("000000").`when`(telephonyManager).getSimOperator()
+
+        val subId = -2 // Use invalid subId to avoid getting resource from cache or real subId.
+        val config = context.resources.configuration
+        var res = notificationUpdater.getResourcesForSubId(context, subId)
+        assertEquals(config.mcc, res.configuration.mcc)
+        assertEquals(config.mnc, res.configuration.mnc)
+
+        doReturn(VERIZON_CARRIER_ID).`when`(telephonyManager).getSimCarrierId()
+        res = notificationUpdater.getResourcesForSubId(context, subId)
+        assertEquals(config.mcc, res.configuration.mcc)
+        assertEquals(config.mnc, res.configuration.mnc)
+
+        doReturn("20404").`when`(telephonyManager).getSimOperator()
+        res = notificationUpdater.getResourcesForSubId(context, subId)
+        assertEquals(311, res.configuration.mcc)
+        assertEquals(480, res.configuration.mnc)
+    }
+
+    @Test
+    fun testRoamingNotification() {
+        val disableIntent = Intent(ACTION_DISABLE_TETHERING).setPackage(context.packageName)
+        val settingsIntent = Intent(Settings.ACTION_TETHER_SETTINGS)
+                .setPackage(getSettingsPackageName(context.packageManager))
+                .addFlags(Intent.FLAG_ACTIVITY_NEW_TASK)
+
+        // Set test sub id.
+        notificationUpdater.onActiveDataSubscriptionIdChanged(TEST_SUBID)
+        verifyNotificationCancelled(listOf(NO_UPSTREAM_NOTIFICATION_ID, ROAMING_NOTIFICATION_ID))
+
+        // Wifi downstream.
+        notificationUpdater.onDownstreamChanged(WIFI_MASK)
+        verifyNotificationCancelled(listOf(NO_UPSTREAM_NOTIFICATION_ID, ROAMING_NOTIFICATION_ID))
+
+        // Upstream capabilities changed to roaming state. Show roaming notification.
+        notificationUpdater.onUpstreamCapabilitiesChanged(ROAMING_CAPABILITIES)
+        verifyNotification(NOTIFICATION_ICON_ID, TEST_ROAMING_TITLE, TEST_ROAMING_MESSAGE,
+                ROAMING_NOTIFICATION_ID, ACTIVITY_PENDING_INTENT, settingsIntent, FLAG_IMMUTABLE)
+
+        // Same capabilities change. Nothing happened.
+        notificationUpdater.onUpstreamCapabilitiesChanged(ROAMING_CAPABILITIES)
+        verifyZeroInteractions(notificationManager)
+
+        // Upstream capabilities changed to home state. Clear roaming notification.
+        notificationUpdater.onUpstreamCapabilitiesChanged(HOME_CAPABILITIES)
+        verifyNotificationCancelled(listOf(ROAMING_NOTIFICATION_ID))
+
+        // Upstream capabilities changed to roaming state again. Show roaming notification.
+        notificationUpdater.onUpstreamCapabilitiesChanged(ROAMING_CAPABILITIES)
+        verifyNotification(NOTIFICATION_ICON_ID, TEST_ROAMING_TITLE, TEST_ROAMING_MESSAGE,
+                ROAMING_NOTIFICATION_ID, ACTIVITY_PENDING_INTENT, settingsIntent, FLAG_IMMUTABLE)
+
+        // No upstream. Clear roaming notification and show no upstream notification.
+        notificationUpdater.onUpstreamCapabilitiesChanged(null)
+        notificationUpdater.handler.waitForDelayedMessage(EVENT_SHOW_NO_UPSTREAM, TIMEOUT_MS)
+        verifyNotificationCancelled(listOf(ROAMING_NOTIFICATION_ID), false)
+        verifyNotification(NOTIFICATION_ICON_ID, TEST_NO_UPSTREAM_TITLE, TEST_NO_UPSTREAM_MESSAGE,
+                NO_UPSTREAM_NOTIFICATION_ID, BROADCAST_PENDING_INTENT, disableIntent,
+                FLAG_IMMUTABLE)
+
+        // No downstream.
+        notificationUpdater.onDownstreamChanged(DOWNSTREAM_NONE)
+        verifyNotificationCancelled(listOf(NO_UPSTREAM_NOTIFICATION_ID, ROAMING_NOTIFICATION_ID))
+
+        // Wifi downstream again.
+        notificationUpdater.onDownstreamChanged(WIFI_MASK)
+        notificationUpdater.handler.waitForDelayedMessage(EVENT_SHOW_NO_UPSTREAM, TIMEOUT_MS)
+        verifyNotificationCancelled(listOf(ROAMING_NOTIFICATION_ID), false)
+        verifyNotification(NOTIFICATION_ICON_ID, TEST_NO_UPSTREAM_TITLE, TEST_NO_UPSTREAM_MESSAGE,
+                NO_UPSTREAM_NOTIFICATION_ID, BROADCAST_PENDING_INTENT, disableIntent,
+                FLAG_IMMUTABLE)
+
+        // Set R.bool.config_upstream_roaming_notification to false and change upstream
+        // network to roaming state again. No roaming notification.
+        doReturn(false).`when`(testResources)
+                .getBoolean(R.bool.config_upstream_roaming_notification)
+        notificationUpdater.onUpstreamCapabilitiesChanged(ROAMING_CAPABILITIES)
+        verifyNotificationCancelled(listOf(NO_UPSTREAM_NOTIFICATION_ID, ROAMING_NOTIFICATION_ID))
+    }
+
+    @Test
+    fun testGetSettingsPackageName() {
+        val defaultSettingsPackageName = "com.android.settings"
+        val testSettingsPackageName = "com.android.test.settings"
+        val pm = mock(PackageManager::class.java)
+        doReturn(null).`when`(pm).resolveActivity(any(), anyInt())
+        assertEquals(defaultSettingsPackageName, getSettingsPackageName(pm))
+
+        val resolveInfo = ResolveInfo().apply {
+            activityInfo = ActivityInfo().apply {
+                name = "test"
+                applicationInfo = ApplicationInfo().apply {
+                    packageName = testSettingsPackageName
+                }
+            }
+        }
+        doReturn(resolveInfo).`when`(pm).resolveActivity(any(), anyInt())
+        assertEquals(testSettingsPackageName, getSettingsPackageName(pm))
+    }
+}
diff --git a/Tethering/tests/unit/src/com/android/networkstack/tethering/TetheringServiceTest.java b/Tethering/tests/unit/src/com/android/networkstack/tethering/TetheringServiceTest.java
new file mode 100644
index 0000000..7bba67b
--- /dev/null
+++ b/Tethering/tests/unit/src/com/android/networkstack/tethering/TetheringServiceTest.java
@@ -0,0 +1,484 @@
+/*
+ * Copyright (C) 2020 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.android.networkstack.tethering;
+
+import static android.Manifest.permission.ACCESS_NETWORK_STATE;
+import static android.Manifest.permission.TETHER_PRIVILEGED;
+import static android.Manifest.permission.WRITE_SETTINGS;
+import static android.net.TetheringManager.TETHERING_WIFI;
+import static android.net.TetheringManager.TETHER_ERROR_NO_ACCESS_TETHERING_PERMISSION;
+import static android.net.TetheringManager.TETHER_ERROR_NO_CHANGE_TETHERING_PERMISSION;
+import static android.net.TetheringManager.TETHER_ERROR_NO_ERROR;
+
+import static org.junit.Assert.assertEquals;
+import static org.mockito.ArgumentMatchers.eq;
+import static org.mockito.Mockito.reset;
+import static org.mockito.Mockito.verify;
+import static org.mockito.Mockito.verifyNoMoreInteractions;
+import static org.mockito.Mockito.when;
+
+import android.app.UiAutomation;
+import android.content.Intent;
+import android.net.IIntResultListener;
+import android.net.ITetheringConnector;
+import android.net.ITetheringEventCallback;
+import android.net.TetheringRequestParcel;
+import android.os.Bundle;
+import android.os.Handler;
+import android.os.ResultReceiver;
+
+import androidx.test.InstrumentationRegistry;
+import androidx.test.filters.SmallTest;
+import androidx.test.rule.ServiceTestRule;
+import androidx.test.runner.AndroidJUnit4;
+
+import com.android.networkstack.tethering.MockTetheringService.MockTetheringConnector;
+
+import org.junit.After;
+import org.junit.Before;
+import org.junit.Rule;
+import org.junit.Test;
+import org.junit.runner.RunWith;
+import org.mockito.Mock;
+import org.mockito.MockitoAnnotations;
+
+@RunWith(AndroidJUnit4.class)
+@SmallTest
+public final class TetheringServiceTest {
+    private static final String TEST_IFACE_NAME = "test_wlan0";
+    private static final String TEST_CALLER_PKG = "com.android.shell";
+    private static final String TEST_ATTRIBUTION_TAG = null;
+    @Mock private ITetheringEventCallback mITetheringEventCallback;
+    @Rule public ServiceTestRule mServiceTestRule;
+    private Tethering mTethering;
+    private Intent mMockServiceIntent;
+    private ITetheringConnector mTetheringConnector;
+    private UiAutomation mUiAutomation;
+
+    private class TestTetheringResult extends IIntResultListener.Stub {
+        private int mResult = -1; // Default value that does not match any result code.
+        @Override
+        public void onResult(final int resultCode) {
+            mResult = resultCode;
+        }
+
+        public void assertResult(final int expected) {
+            assertEquals(expected, mResult);
+        }
+    }
+
+    private class MyResultReceiver extends ResultReceiver {
+        MyResultReceiver(Handler handler) {
+            super(handler);
+        }
+        private int mResult = -1; // Default value that does not match any result code.
+        @Override
+        protected void onReceiveResult(int resultCode, Bundle resultData) {
+            mResult = resultCode;
+        }
+
+        public void assertResult(int expected) {
+            assertEquals(expected, mResult);
+        }
+    }
+
+    @Before
+    public void setUp() throws Exception {
+        MockitoAnnotations.initMocks(this);
+        mUiAutomation =
+            InstrumentationRegistry.getInstrumentation().getUiAutomation();
+        mServiceTestRule = new ServiceTestRule();
+        mMockServiceIntent = new Intent(
+                InstrumentationRegistry.getTargetContext(),
+                MockTetheringService.class);
+        final MockTetheringConnector mockConnector =
+                (MockTetheringConnector) mServiceTestRule.bindService(mMockServiceIntent);
+        mTetheringConnector = mockConnector.getTetheringConnector();
+        final MockTetheringService service = mockConnector.getService();
+        mTethering = service.getTethering();
+    }
+
+    @After
+    public void tearDown() throws Exception {
+        mServiceTestRule.unbindService();
+        mUiAutomation.dropShellPermissionIdentity();
+    }
+
+    private interface TestTetheringCall {
+        void runTetheringCall(TestTetheringResult result) throws Exception;
+    }
+
+    private void runAsNoPermission(final TestTetheringCall test) throws Exception {
+        runTetheringCall(test, new String[0]);
+    }
+
+    private void runAsTetherPrivileged(final TestTetheringCall test) throws Exception {
+        runTetheringCall(test, TETHER_PRIVILEGED);
+    }
+
+    private void runAsAccessNetworkState(final TestTetheringCall test) throws Exception {
+        runTetheringCall(test, ACCESS_NETWORK_STATE);
+    }
+
+    private void runAsWriteSettings(final TestTetheringCall test) throws Exception {
+        runTetheringCall(test, WRITE_SETTINGS);
+    }
+
+    private void runTetheringCall(final TestTetheringCall test, String... permissions)
+            throws Exception {
+        if (permissions.length > 0) mUiAutomation.adoptShellPermissionIdentity(permissions);
+        try {
+            when(mTethering.isTetheringSupported()).thenReturn(true);
+            test.runTetheringCall(new TestTetheringResult());
+        } finally {
+            mUiAutomation.dropShellPermissionIdentity();
+        }
+    }
+
+    private void verifyNoMoreInteractionsForTethering() {
+        verifyNoMoreInteractions(mTethering);
+        verifyNoMoreInteractions(mITetheringEventCallback);
+        reset(mTethering, mITetheringEventCallback);
+    }
+
+    private void runTether(final TestTetheringResult result) throws Exception {
+        when(mTethering.tether(TEST_IFACE_NAME)).thenReturn(TETHER_ERROR_NO_ERROR);
+        mTetheringConnector.tether(TEST_IFACE_NAME, TEST_CALLER_PKG, TEST_ATTRIBUTION_TAG, result);
+        verify(mTethering).isTetheringSupported();
+        verify(mTethering).tether(TEST_IFACE_NAME);
+        result.assertResult(TETHER_ERROR_NO_ERROR);
+    }
+
+    @Test
+    public void testTether() throws Exception {
+        runAsNoPermission((result) -> {
+            mTetheringConnector.tether(TEST_IFACE_NAME, TEST_CALLER_PKG, TEST_ATTRIBUTION_TAG,
+                    result);
+            verify(mTethering).isTetherProvisioningRequired();
+            result.assertResult(TETHER_ERROR_NO_CHANGE_TETHERING_PERMISSION);
+            verifyNoMoreInteractionsForTethering();
+        });
+
+        runAsTetherPrivileged((result) -> {
+            runTether(result);
+            verifyNoMoreInteractionsForTethering();
+        });
+
+        runAsWriteSettings((result) -> {
+            runTether(result);
+            verify(mTethering).isTetherProvisioningRequired();
+            verifyNoMoreInteractionsForTethering();
+        });
+    }
+
+    private void runUnTether(final TestTetheringResult result) throws Exception {
+        when(mTethering.untether(TEST_IFACE_NAME)).thenReturn(TETHER_ERROR_NO_ERROR);
+        mTetheringConnector.untether(TEST_IFACE_NAME, TEST_CALLER_PKG, TEST_ATTRIBUTION_TAG,
+                result);
+        verify(mTethering).isTetheringSupported();
+        verify(mTethering).untether(TEST_IFACE_NAME);
+        result.assertResult(TETHER_ERROR_NO_ERROR);
+    }
+
+    @Test
+    public void testUntether() throws Exception {
+        runAsNoPermission((result) -> {
+            mTetheringConnector.untether(TEST_IFACE_NAME, TEST_CALLER_PKG, TEST_ATTRIBUTION_TAG,
+                    result);
+            verify(mTethering).isTetherProvisioningRequired();
+            result.assertResult(TETHER_ERROR_NO_CHANGE_TETHERING_PERMISSION);
+            verifyNoMoreInteractionsForTethering();
+        });
+
+        runAsTetherPrivileged((result) -> {
+            runUnTether(result);
+            verifyNoMoreInteractionsForTethering();
+        });
+
+        runAsWriteSettings((result) -> {
+            runUnTether(result);
+            verify(mTethering).isTetherProvisioningRequired();
+            verifyNoMoreInteractionsForTethering();
+        });
+    }
+
+    private void runSetUsbTethering(final TestTetheringResult result) throws Exception {
+        when(mTethering.setUsbTethering(true /* enable */)).thenReturn(TETHER_ERROR_NO_ERROR);
+        mTetheringConnector.setUsbTethering(true /* enable */, TEST_CALLER_PKG,
+                TEST_ATTRIBUTION_TAG, result);
+        verify(mTethering).isTetheringSupported();
+        verify(mTethering).setUsbTethering(true /* enable */);
+        result.assertResult(TETHER_ERROR_NO_ERROR);
+    }
+
+    @Test
+    public void testSetUsbTethering() throws Exception {
+        runAsNoPermission((result) -> {
+            mTetheringConnector.setUsbTethering(true /* enable */, TEST_CALLER_PKG,
+                    TEST_ATTRIBUTION_TAG, result);
+            verify(mTethering).isTetherProvisioningRequired();
+            result.assertResult(TETHER_ERROR_NO_CHANGE_TETHERING_PERMISSION);
+            verifyNoMoreInteractionsForTethering();
+        });
+
+        runAsTetherPrivileged((result) -> {
+            runSetUsbTethering(result);
+            verifyNoMoreInteractionsForTethering();
+        });
+
+        runAsWriteSettings((result) -> {
+            runSetUsbTethering(result);
+            verify(mTethering).isTetherProvisioningRequired();
+            verifyNoMoreInteractionsForTethering();
+        });
+
+    }
+
+    private void runStartTethering(final TestTetheringResult result,
+            final TetheringRequestParcel request) throws Exception {
+        mTetheringConnector.startTethering(request, TEST_CALLER_PKG, TEST_ATTRIBUTION_TAG,
+                result);
+        verify(mTethering).isTetheringSupported();
+        verify(mTethering).startTethering(eq(request), eq(result));
+    }
+
+    @Test
+    public void testStartTethering() throws Exception {
+        final TetheringRequestParcel request = new TetheringRequestParcel();
+        request.tetheringType = TETHERING_WIFI;
+
+        runAsNoPermission((result) -> {
+            mTetheringConnector.startTethering(request, TEST_CALLER_PKG, TEST_ATTRIBUTION_TAG,
+                    result);
+            verify(mTethering).isTetherProvisioningRequired();
+            result.assertResult(TETHER_ERROR_NO_CHANGE_TETHERING_PERMISSION);
+            verifyNoMoreInteractionsForTethering();
+        });
+
+        runAsTetherPrivileged((result) -> {
+            runStartTethering(result, request);
+            verifyNoMoreInteractionsForTethering();
+        });
+
+        runAsWriteSettings((result) -> {
+            runStartTethering(result, request);
+            verify(mTethering).isTetherProvisioningRequired();
+            verifyNoMoreInteractionsForTethering();
+        });
+    }
+
+    private void runStartTetheringAndVerifyNoPermission(final TestTetheringResult result)
+            throws Exception {
+        final TetheringRequestParcel request = new TetheringRequestParcel();
+        request.tetheringType = TETHERING_WIFI;
+        request.exemptFromEntitlementCheck = true;
+        mTetheringConnector.startTethering(request, TEST_CALLER_PKG, TEST_ATTRIBUTION_TAG,
+                result);
+        result.assertResult(TETHER_ERROR_NO_CHANGE_TETHERING_PERMISSION);
+        verifyNoMoreInteractionsForTethering();
+    }
+
+    @Test
+    public void testFailToBypassEntitlementWithoutNeworkStackPermission() throws Exception {
+        final TetheringRequestParcel request = new TetheringRequestParcel();
+        request.tetheringType = TETHERING_WIFI;
+        request.exemptFromEntitlementCheck = true;
+
+        runAsNoPermission((result) -> {
+            runStartTetheringAndVerifyNoPermission(result);
+        });
+
+        runAsTetherPrivileged((result) -> {
+            runStartTetheringAndVerifyNoPermission(result);
+        });
+
+        runAsWriteSettings((result) -> {
+            runStartTetheringAndVerifyNoPermission(result);
+        });
+    }
+
+    private void runStopTethering(final TestTetheringResult result) throws Exception {
+        mTetheringConnector.stopTethering(TETHERING_WIFI, TEST_CALLER_PKG,
+                TEST_ATTRIBUTION_TAG, result);
+        verify(mTethering).isTetheringSupported();
+        verify(mTethering).stopTethering(TETHERING_WIFI);
+        result.assertResult(TETHER_ERROR_NO_ERROR);
+    }
+
+    @Test
+    public void testStopTethering() throws Exception {
+        runAsNoPermission((result) -> {
+            mTetheringConnector.stopTethering(TETHERING_WIFI, TEST_CALLER_PKG,
+                    TEST_ATTRIBUTION_TAG, result);
+            verify(mTethering).isTetherProvisioningRequired();
+            result.assertResult(TETHER_ERROR_NO_CHANGE_TETHERING_PERMISSION);
+            verifyNoMoreInteractionsForTethering();
+        });
+
+        runAsTetherPrivileged((result) -> {
+            runStopTethering(result);
+            verifyNoMoreInteractionsForTethering();
+        });
+
+        runAsWriteSettings((result) -> {
+            runStopTethering(result);
+            verify(mTethering).isTetherProvisioningRequired();
+            verifyNoMoreInteractionsForTethering();
+        });
+    }
+
+    private void runRequestLatestTetheringEntitlementResult() throws Exception {
+        final MyResultReceiver result = new MyResultReceiver(null);
+        mTetheringConnector.requestLatestTetheringEntitlementResult(TETHERING_WIFI, result,
+                true /* showEntitlementUi */, TEST_CALLER_PKG, TEST_ATTRIBUTION_TAG);
+        verify(mTethering).isTetheringSupported();
+        verify(mTethering).requestLatestTetheringEntitlementResult(eq(TETHERING_WIFI),
+                eq(result), eq(true) /* showEntitlementUi */);
+    }
+
+    @Test
+    public void testRequestLatestTetheringEntitlementResult() throws Exception {
+        // Run as no permission.
+        final MyResultReceiver result = new MyResultReceiver(null);
+        mTetheringConnector.requestLatestTetheringEntitlementResult(TETHERING_WIFI, result,
+                true /* showEntitlementUi */, TEST_CALLER_PKG, TEST_ATTRIBUTION_TAG);
+        verify(mTethering).isTetherProvisioningRequired();
+        result.assertResult(TETHER_ERROR_NO_CHANGE_TETHERING_PERMISSION);
+        verifyNoMoreInteractions(mTethering);
+
+        runAsTetherPrivileged((none) -> {
+            runRequestLatestTetheringEntitlementResult();
+            verifyNoMoreInteractionsForTethering();
+        });
+
+        runAsWriteSettings((none) -> {
+            runRequestLatestTetheringEntitlementResult();
+            verify(mTethering).isTetherProvisioningRequired();
+            verifyNoMoreInteractionsForTethering();
+        });
+    }
+
+    private void runRegisterTetheringEventCallback() throws Exception {
+        mTetheringConnector.registerTetheringEventCallback(mITetheringEventCallback,
+                TEST_CALLER_PKG);
+        verify(mTethering).registerTetheringEventCallback(eq(mITetheringEventCallback));
+    }
+
+    @Test
+    public void testRegisterTetheringEventCallback() throws Exception {
+        runAsNoPermission((result) -> {
+            mTetheringConnector.registerTetheringEventCallback(mITetheringEventCallback,
+                    TEST_CALLER_PKG);
+            verify(mITetheringEventCallback).onCallbackStopped(
+                    TETHER_ERROR_NO_ACCESS_TETHERING_PERMISSION);
+            verifyNoMoreInteractionsForTethering();
+        });
+
+        runAsTetherPrivileged((none) -> {
+            runRegisterTetheringEventCallback();
+            verifyNoMoreInteractionsForTethering();
+        });
+
+        runAsAccessNetworkState((none) -> {
+            runRegisterTetheringEventCallback();
+            verifyNoMoreInteractionsForTethering();
+        });
+    }
+
+    private void runUnregisterTetheringEventCallback() throws Exception {
+        mTetheringConnector.unregisterTetheringEventCallback(mITetheringEventCallback,
+                TEST_CALLER_PKG);
+        verify(mTethering).unregisterTetheringEventCallback(eq(mITetheringEventCallback));
+    }
+
+    @Test
+    public void testUnregisterTetheringEventCallback() throws Exception {
+        runAsNoPermission((result) -> {
+            mTetheringConnector.unregisterTetheringEventCallback(mITetheringEventCallback,
+                    TEST_CALLER_PKG);
+            verify(mITetheringEventCallback).onCallbackStopped(
+                    TETHER_ERROR_NO_ACCESS_TETHERING_PERMISSION);
+            verifyNoMoreInteractionsForTethering();
+        });
+
+        runAsTetherPrivileged((none) -> {
+            runUnregisterTetheringEventCallback();
+            verifyNoMoreInteractionsForTethering();
+        });
+
+        runAsAccessNetworkState((none) -> {
+            runUnregisterTetheringEventCallback();
+            verifyNoMoreInteractionsForTethering();
+        });
+    }
+
+    private void runStopAllTethering(final TestTetheringResult result) throws Exception {
+        mTetheringConnector.stopAllTethering(TEST_CALLER_PKG, TEST_ATTRIBUTION_TAG, result);
+        verify(mTethering).isTetheringSupported();
+        verify(mTethering).untetherAll();
+        result.assertResult(TETHER_ERROR_NO_ERROR);
+    }
+
+    @Test
+    public void testStopAllTethering() throws Exception {
+        runAsNoPermission((result) -> {
+            mTetheringConnector.stopAllTethering(TEST_CALLER_PKG, TEST_ATTRIBUTION_TAG, result);
+            verify(mTethering).isTetherProvisioningRequired();
+            result.assertResult(TETHER_ERROR_NO_CHANGE_TETHERING_PERMISSION);
+            verifyNoMoreInteractionsForTethering();
+        });
+
+        runAsTetherPrivileged((result) -> {
+            runStopAllTethering(result);
+            verifyNoMoreInteractionsForTethering();
+        });
+
+        runAsWriteSettings((result) -> {
+            runStopAllTethering(result);
+            verify(mTethering).isTetherProvisioningRequired();
+            verifyNoMoreInteractionsForTethering();
+        });
+    }
+
+    private void runIsTetheringSupported(final TestTetheringResult result) throws Exception {
+        mTetheringConnector.isTetheringSupported(TEST_CALLER_PKG, TEST_ATTRIBUTION_TAG, result);
+        verify(mTethering).isTetheringSupported();
+        result.assertResult(TETHER_ERROR_NO_ERROR);
+    }
+
+    @Test
+    public void testIsTetheringSupported() throws Exception {
+        runAsNoPermission((result) -> {
+            mTetheringConnector.isTetheringSupported(TEST_CALLER_PKG, TEST_ATTRIBUTION_TAG,
+                    result);
+            verify(mTethering).isTetherProvisioningRequired();
+            result.assertResult(TETHER_ERROR_NO_CHANGE_TETHERING_PERMISSION);
+            verifyNoMoreInteractionsForTethering();
+        });
+
+        runAsTetherPrivileged((result) -> {
+            runIsTetheringSupported(result);
+            verifyNoMoreInteractionsForTethering();
+        });
+
+        runAsWriteSettings((result) -> {
+            runIsTetheringSupported(result);
+            verify(mTethering).isTetherProvisioningRequired();
+            verifyNoMoreInteractionsForTethering();
+        });
+    }
+}
diff --git a/Tethering/tests/unit/src/com/android/networkstack/tethering/TetheringTest.java b/Tethering/tests/unit/src/com/android/networkstack/tethering/TetheringTest.java
new file mode 100644
index 0000000..114cb7c
--- /dev/null
+++ b/Tethering/tests/unit/src/com/android/networkstack/tethering/TetheringTest.java
@@ -0,0 +1,2019 @@
+/*
+ * Copyright (C) 2016 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.android.networkstack.tethering;
+
+import static android.content.pm.PackageManager.GET_ACTIVITIES;
+import static android.hardware.usb.UsbManager.USB_CONFIGURED;
+import static android.hardware.usb.UsbManager.USB_CONNECTED;
+import static android.hardware.usb.UsbManager.USB_FUNCTION_NCM;
+import static android.hardware.usb.UsbManager.USB_FUNCTION_RNDIS;
+import static android.net.ConnectivityManager.ACTION_RESTRICT_BACKGROUND_CHANGED;
+import static android.net.ConnectivityManager.RESTRICT_BACKGROUND_STATUS_DISABLED;
+import static android.net.ConnectivityManager.RESTRICT_BACKGROUND_STATUS_ENABLED;
+import static android.net.NetworkCapabilities.TRANSPORT_BLUETOOTH;
+import static android.net.NetworkCapabilities.TRANSPORT_CELLULAR;
+import static android.net.NetworkCapabilities.TRANSPORT_WIFI;
+import static android.net.RouteInfo.RTN_UNICAST;
+import static android.net.TetheringManager.ACTION_TETHER_STATE_CHANGED;
+import static android.net.TetheringManager.EXTRA_ACTIVE_LOCAL_ONLY;
+import static android.net.TetheringManager.EXTRA_ACTIVE_TETHER;
+import static android.net.TetheringManager.EXTRA_AVAILABLE_TETHER;
+import static android.net.TetheringManager.TETHERING_ETHERNET;
+import static android.net.TetheringManager.TETHERING_NCM;
+import static android.net.TetheringManager.TETHERING_USB;
+import static android.net.TetheringManager.TETHERING_WIFI;
+import static android.net.TetheringManager.TETHER_ERROR_IFACE_CFG_ERROR;
+import static android.net.TetheringManager.TETHER_ERROR_NO_ERROR;
+import static android.net.TetheringManager.TETHER_ERROR_UNKNOWN_IFACE;
+import static android.net.TetheringManager.TETHER_HARDWARE_OFFLOAD_FAILED;
+import static android.net.TetheringManager.TETHER_HARDWARE_OFFLOAD_STARTED;
+import static android.net.TetheringManager.TETHER_HARDWARE_OFFLOAD_STOPPED;
+import static android.net.dhcp.IDhcpServer.STATUS_SUCCESS;
+import static android.net.wifi.WifiManager.EXTRA_WIFI_AP_INTERFACE_NAME;
+import static android.net.wifi.WifiManager.EXTRA_WIFI_AP_MODE;
+import static android.net.wifi.WifiManager.EXTRA_WIFI_AP_STATE;
+import static android.net.wifi.WifiManager.IFACE_IP_MODE_LOCAL_ONLY;
+import static android.net.wifi.WifiManager.IFACE_IP_MODE_TETHERED;
+import static android.net.wifi.WifiManager.WIFI_AP_STATE_ENABLED;
+import static android.telephony.SubscriptionManager.INVALID_SUBSCRIPTION_ID;
+
+import static com.android.net.module.util.Inet4AddressUtils.intToInet4AddressHTH;
+import static com.android.networkstack.tethering.TetheringNotificationUpdater.DOWNSTREAM_NONE;
+import static com.android.networkstack.tethering.UpstreamNetworkMonitor.EVENT_ON_CAPABILITIES;
+
+import static org.junit.Assert.assertArrayEquals;
+import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertFalse;
+import static org.junit.Assert.assertTrue;
+import static org.junit.Assert.fail;
+import static org.mockito.ArgumentMatchers.argThat;
+import static org.mockito.ArgumentMatchers.notNull;
+import static org.mockito.Matchers.anyInt;
+import static org.mockito.Matchers.anyString;
+import static org.mockito.Matchers.eq;
+import static org.mockito.Mockito.any;
+import static org.mockito.Mockito.doThrow;
+import static org.mockito.Mockito.mock;
+import static org.mockito.Mockito.never;
+import static org.mockito.Mockito.reset;
+import static org.mockito.Mockito.spy;
+import static org.mockito.Mockito.timeout;
+import static org.mockito.Mockito.times;
+import static org.mockito.Mockito.verify;
+import static org.mockito.Mockito.verifyNoMoreInteractions;
+import static org.mockito.Mockito.when;
+
+import android.app.usage.NetworkStatsManager;
+import android.bluetooth.BluetoothAdapter;
+import android.content.BroadcastReceiver;
+import android.content.ContentResolver;
+import android.content.Context;
+import android.content.Intent;
+import android.content.IntentFilter;
+import android.content.pm.ApplicationInfo;
+import android.content.pm.PackageManager;
+import android.content.res.Resources;
+import android.hardware.usb.UsbManager;
+import android.net.ConnectivityManager;
+import android.net.EthernetManager;
+import android.net.EthernetManager.TetheredInterfaceCallback;
+import android.net.EthernetManager.TetheredInterfaceRequest;
+import android.net.IIntResultListener;
+import android.net.INetd;
+import android.net.ITetheringEventCallback;
+import android.net.InetAddresses;
+import android.net.InterfaceConfigurationParcel;
+import android.net.IpPrefix;
+import android.net.LinkAddress;
+import android.net.LinkProperties;
+import android.net.MacAddress;
+import android.net.Network;
+import android.net.NetworkCapabilities;
+import android.net.NetworkRequest;
+import android.net.RouteInfo;
+import android.net.TetherStatesParcel;
+import android.net.TetheredClient;
+import android.net.TetheringCallbackStartedParcel;
+import android.net.TetheringConfigurationParcel;
+import android.net.TetheringRequestParcel;
+import android.net.dhcp.DhcpServerCallbacks;
+import android.net.dhcp.DhcpServingParamsParcel;
+import android.net.dhcp.IDhcpServer;
+import android.net.ip.DadProxy;
+import android.net.ip.IpNeighborMonitor;
+import android.net.ip.IpServer;
+import android.net.ip.RouterAdvertisementDaemon;
+import android.net.util.InterfaceParams;
+import android.net.util.NetworkConstants;
+import android.net.util.SharedLog;
+import android.net.wifi.SoftApConfiguration;
+import android.net.wifi.WifiManager;
+import android.net.wifi.p2p.WifiP2pGroup;
+import android.net.wifi.p2p.WifiP2pInfo;
+import android.net.wifi.p2p.WifiP2pManager;
+import android.os.Bundle;
+import android.os.Handler;
+import android.os.Looper;
+import android.os.PersistableBundle;
+import android.os.RemoteException;
+import android.os.UserHandle;
+import android.os.UserManager;
+import android.os.test.TestLooper;
+import android.provider.Settings;
+import android.telephony.CarrierConfigManager;
+import android.telephony.PhoneStateListener;
+import android.telephony.TelephonyManager;
+import android.test.mock.MockContentResolver;
+
+import androidx.annotation.NonNull;
+import androidx.test.filters.SmallTest;
+import androidx.test.runner.AndroidJUnit4;
+
+import com.android.internal.util.ArrayUtils;
+import com.android.internal.util.StateMachine;
+import com.android.internal.util.test.BroadcastInterceptingContext;
+import com.android.internal.util.test.FakeSettingsProvider;
+import com.android.testutils.MiscAsserts;
+
+import org.junit.After;
+import org.junit.AfterClass;
+import org.junit.Before;
+import org.junit.BeforeClass;
+import org.junit.Test;
+import org.junit.runner.RunWith;
+import org.mockito.ArgumentCaptor;
+import org.mockito.Mock;
+import org.mockito.MockitoAnnotations;
+
+import java.io.FileDescriptor;
+import java.io.PrintWriter;
+import java.net.Inet4Address;
+import java.net.Inet6Address;
+import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.Collection;
+import java.util.List;
+import java.util.Vector;
+
+@RunWith(AndroidJUnit4.class)
+@SmallTest
+public class TetheringTest {
+    private static final int IFINDEX_OFFSET = 100;
+
+    private static final String TEST_MOBILE_IFNAME = "test_rmnet_data0";
+    private static final String TEST_XLAT_MOBILE_IFNAME = "v4-test_rmnet_data0";
+    private static final String TEST_USB_IFNAME = "test_rndis0";
+    private static final String TEST_WIFI_IFNAME = "test_wlan0";
+    private static final String TEST_WLAN_IFNAME = "test_wlan1";
+    private static final String TEST_P2P_IFNAME = "test_p2p-p2p0-0";
+    private static final String TEST_NCM_IFNAME = "test_ncm0";
+    private static final String TEST_ETH_IFNAME = "test_eth0";
+    private static final String TEST_BT_IFNAME = "test_pan0";
+    private static final String TETHERING_NAME = "Tethering";
+    private static final String[] PROVISIONING_APP_NAME = {"some", "app"};
+    private static final String PROVISIONING_NO_UI_APP_NAME = "no_ui_app";
+
+    private static final int DHCPSERVER_START_TIMEOUT_MS = 1000;
+
+    @Mock private ApplicationInfo mApplicationInfo;
+    @Mock private Context mContext;
+    @Mock private NetworkStatsManager mStatsManager;
+    @Mock private OffloadHardwareInterface mOffloadHardwareInterface;
+    @Mock private OffloadHardwareInterface.ForwardedStats mForwardedStats;
+    @Mock private Resources mResources;
+    @Mock private TelephonyManager mTelephonyManager;
+    @Mock private UsbManager mUsbManager;
+    @Mock private WifiManager mWifiManager;
+    @Mock private CarrierConfigManager mCarrierConfigManager;
+    @Mock private UpstreamNetworkMonitor mUpstreamNetworkMonitor;
+    @Mock private IPv6TetheringCoordinator mIPv6TetheringCoordinator;
+    @Mock private DadProxy mDadProxy;
+    @Mock private RouterAdvertisementDaemon mRouterAdvertisementDaemon;
+    @Mock private IpNeighborMonitor mIpNeighborMonitor;
+    @Mock private IDhcpServer mDhcpServer;
+    @Mock private INetd mNetd;
+    @Mock private UserManager mUserManager;
+    @Mock private NetworkRequest mNetworkRequest;
+    @Mock private ConnectivityManager mCm;
+    @Mock private EthernetManager mEm;
+    @Mock private TetheringNotificationUpdater mNotificationUpdater;
+    @Mock private BpfCoordinator mBpfCoordinator;
+    @Mock private PackageManager mPackageManager;
+
+    private final MockIpServerDependencies mIpServerDependencies =
+            spy(new MockIpServerDependencies());
+    private final MockTetheringDependencies mTetheringDependencies =
+            new MockTetheringDependencies();
+
+    // Like so many Android system APIs, these cannot be mocked because it is marked final.
+    // We have to use the real versions.
+    private final PersistableBundle mCarrierConfig = new PersistableBundle();
+    private final TestLooper mLooper = new TestLooper();
+
+    private Vector<Intent> mIntents;
+    private BroadcastInterceptingContext mServiceContext;
+    private MockContentResolver mContentResolver;
+    private BroadcastReceiver mBroadcastReceiver;
+    private Tethering mTethering;
+    private PhoneStateListener mPhoneStateListener;
+    private InterfaceConfigurationParcel mInterfaceConfiguration;
+    private TetheringConfiguration mConfig;
+    private EntitlementManager mEntitleMgr;
+    private OffloadController mOffloadCtrl;
+    private PrivateAddressCoordinator mPrivateAddressCoordinator;
+
+    private class TestContext extends BroadcastInterceptingContext {
+        TestContext(Context base) {
+            super(base);
+        }
+
+        @Override
+        public ApplicationInfo getApplicationInfo() {
+            return mApplicationInfo;
+        }
+
+        @Override
+        public ContentResolver getContentResolver() {
+            return mContentResolver;
+        }
+
+        @Override
+        public String getPackageName() {
+            return "TetheringTest";
+        }
+
+        @Override
+        public Resources getResources() {
+            return mResources;
+        }
+
+        @Override
+        public Object getSystemService(String name) {
+            if (Context.WIFI_SERVICE.equals(name)) return mWifiManager;
+            if (Context.USB_SERVICE.equals(name)) return mUsbManager;
+            if (Context.TELEPHONY_SERVICE.equals(name)) return mTelephonyManager;
+            if (Context.USER_SERVICE.equals(name)) return mUserManager;
+            if (Context.NETWORK_STATS_SERVICE.equals(name)) return mStatsManager;
+            if (Context.CONNECTIVITY_SERVICE.equals(name)) return mCm;
+            if (Context.ETHERNET_SERVICE.equals(name)) return mEm;
+            return super.getSystemService(name);
+        }
+
+        @Override
+        public PackageManager getPackageManager() {
+            return mPackageManager;
+        }
+
+        @Override
+        public String getSystemServiceName(Class<?> serviceClass) {
+            if (TelephonyManager.class.equals(serviceClass)) return Context.TELEPHONY_SERVICE;
+            return super.getSystemServiceName(serviceClass);
+        }
+    }
+
+    public class MockIpServerDependencies extends IpServer.Dependencies {
+        @Override
+        public DadProxy getDadProxy(
+                Handler handler, InterfaceParams ifParams) {
+            return mDadProxy;
+        }
+
+        @Override
+        public RouterAdvertisementDaemon getRouterAdvertisementDaemon(
+                InterfaceParams ifParams) {
+            return mRouterAdvertisementDaemon;
+        }
+
+        @Override
+        public InterfaceParams getInterfaceParams(String ifName) {
+            assertTrue("Non-mocked interface " + ifName,
+                    ifName.equals(TEST_USB_IFNAME)
+                            || ifName.equals(TEST_WLAN_IFNAME)
+                            || ifName.equals(TEST_MOBILE_IFNAME)
+                            || ifName.equals(TEST_P2P_IFNAME)
+                            || ifName.equals(TEST_NCM_IFNAME)
+                            || ifName.equals(TEST_ETH_IFNAME));
+            final String[] ifaces = new String[] {
+                    TEST_USB_IFNAME, TEST_WLAN_IFNAME, TEST_MOBILE_IFNAME, TEST_P2P_IFNAME,
+                    TEST_NCM_IFNAME, TEST_ETH_IFNAME};
+            return new InterfaceParams(ifName, ArrayUtils.indexOf(ifaces, ifName) + IFINDEX_OFFSET,
+                    MacAddress.ALL_ZEROS_ADDRESS);
+        }
+
+        @Override
+        public void makeDhcpServer(String ifName, DhcpServingParamsParcel params,
+                DhcpServerCallbacks cb) {
+            new Thread(() -> {
+                try {
+                    cb.onDhcpServerCreated(STATUS_SUCCESS, mDhcpServer);
+                } catch (RemoteException e) {
+                    fail(e.getMessage());
+                }
+            }).run();
+        }
+
+        public IpNeighborMonitor getIpNeighborMonitor(Handler h, SharedLog l,
+                IpNeighborMonitor.NeighborEventConsumer c) {
+            return mIpNeighborMonitor;
+        }
+    }
+
+    // MyTetheringConfiguration is used to override static method for testing.
+    private class MyTetheringConfiguration extends TetheringConfiguration {
+        MyTetheringConfiguration(Context ctx, SharedLog log, int id) {
+            super(ctx, log, id);
+        }
+
+        @Override
+        protected String getDeviceConfigProperty(final String name) {
+            return null;
+        }
+
+        @Override
+        protected Resources getResourcesForSubIdWrapper(Context ctx, int subId) {
+            return mResources;
+        }
+    }
+
+    public class MockTetheringDependencies extends TetheringDependencies {
+        StateMachine mUpstreamNetworkMonitorSM;
+        ArrayList<IpServer> mIpv6CoordinatorNotifyList;
+
+        public void reset() {
+            mUpstreamNetworkMonitorSM = null;
+            mIpv6CoordinatorNotifyList = null;
+        }
+
+        @Override
+        public BpfCoordinator getBpfCoordinator(
+                BpfCoordinator.Dependencies deps) {
+            return mBpfCoordinator;
+        }
+
+        @Override
+        public OffloadHardwareInterface getOffloadHardwareInterface(Handler h, SharedLog log) {
+            return mOffloadHardwareInterface;
+        }
+
+        @Override
+        public OffloadController getOffloadController(Handler h, SharedLog log,
+                OffloadController.Dependencies deps) {
+            mOffloadCtrl = spy(super.getOffloadController(h, log, deps));
+            // Return real object here instead of mock because
+            // testReportFailCallbackIfOffloadNotSupported depend on real OffloadController object.
+            return mOffloadCtrl;
+        }
+
+        @Override
+        public UpstreamNetworkMonitor getUpstreamNetworkMonitor(Context ctx,
+                StateMachine target, SharedLog log, int what) {
+            mUpstreamNetworkMonitorSM = target;
+            return mUpstreamNetworkMonitor;
+        }
+
+        @Override
+        public IPv6TetheringCoordinator getIPv6TetheringCoordinator(
+                ArrayList<IpServer> notifyList, SharedLog log) {
+            mIpv6CoordinatorNotifyList = notifyList;
+            return mIPv6TetheringCoordinator;
+        }
+
+        @Override
+        public IpServer.Dependencies getIpServerDependencies() {
+            return mIpServerDependencies;
+        }
+
+        @Override
+        public NetworkRequest getDefaultNetworkRequest() {
+            return mNetworkRequest;
+        }
+
+        @Override
+        public EntitlementManager getEntitlementManager(Context ctx, Handler h, SharedLog log,
+                Runnable callback) {
+            mEntitleMgr = spy(super.getEntitlementManager(ctx, h, log, callback));
+            return mEntitleMgr;
+        }
+
+        @Override
+        public boolean isTetheringSupported() {
+            return true;
+        }
+
+        @Override
+        public TetheringConfiguration generateTetheringConfiguration(Context ctx, SharedLog log,
+                int subId) {
+            mConfig = spy(new MyTetheringConfiguration(ctx, log, subId));
+            return mConfig;
+        }
+
+        @Override
+        public INetd getINetd(Context context) {
+            return mNetd;
+        }
+
+        @Override
+        public Looper getTetheringLooper() {
+            return mLooper.getLooper();
+        }
+
+        @Override
+        public Context getContext() {
+            return mServiceContext;
+        }
+
+        @Override
+        public BluetoothAdapter getBluetoothAdapter() {
+            // TODO: add test for bluetooth tethering.
+            return null;
+        }
+
+        @Override
+        public TetheringNotificationUpdater getNotificationUpdater(Context ctx, Looper looper) {
+            return mNotificationUpdater;
+        }
+
+        @Override
+        public boolean isTetheringDenied() {
+            return false;
+        }
+
+
+        @Override
+        public PrivateAddressCoordinator getPrivateAddressCoordinator(Context ctx,
+                TetheringConfiguration cfg) {
+            mPrivateAddressCoordinator = super.getPrivateAddressCoordinator(ctx, cfg);
+            return mPrivateAddressCoordinator;
+        }
+    }
+
+    private static UpstreamNetworkState buildMobileUpstreamState(boolean withIPv4,
+            boolean withIPv6, boolean with464xlat) {
+        final LinkProperties prop = new LinkProperties();
+        prop.setInterfaceName(TEST_MOBILE_IFNAME);
+
+        if (withIPv4) {
+            prop.addRoute(new RouteInfo(new IpPrefix(Inet4Address.ANY, 0),
+                    InetAddresses.parseNumericAddress("10.0.0.1"),
+                    TEST_MOBILE_IFNAME, RTN_UNICAST));
+        }
+
+        if (withIPv6) {
+            prop.addDnsServer(InetAddresses.parseNumericAddress("2001:db8::2"));
+            prop.addLinkAddress(
+                    new LinkAddress(InetAddresses.parseNumericAddress("2001:db8::"),
+                            NetworkConstants.RFC7421_PREFIX_LENGTH));
+            prop.addRoute(new RouteInfo(new IpPrefix(Inet6Address.ANY, 0),
+                    InetAddresses.parseNumericAddress("2001:db8::1"),
+                    TEST_MOBILE_IFNAME, RTN_UNICAST));
+        }
+
+        if (with464xlat) {
+            final LinkProperties stackedLink = new LinkProperties();
+            stackedLink.setInterfaceName(TEST_XLAT_MOBILE_IFNAME);
+            stackedLink.addRoute(new RouteInfo(new IpPrefix(Inet4Address.ANY, 0),
+                    InetAddresses.parseNumericAddress("192.0.0.1"),
+                    TEST_XLAT_MOBILE_IFNAME, RTN_UNICAST));
+
+            prop.addStackedLink(stackedLink);
+        }
+
+
+        final NetworkCapabilities capabilities = new NetworkCapabilities()
+                .addTransportType(NetworkCapabilities.TRANSPORT_CELLULAR);
+        return new UpstreamNetworkState(prop, capabilities, new Network(100));
+    }
+
+    private static UpstreamNetworkState buildMobileIPv4UpstreamState() {
+        return buildMobileUpstreamState(true, false, false);
+    }
+
+    private static UpstreamNetworkState buildMobileIPv6UpstreamState() {
+        return buildMobileUpstreamState(false, true, false);
+    }
+
+    private static UpstreamNetworkState buildMobileDualStackUpstreamState() {
+        return buildMobileUpstreamState(true, true, false);
+    }
+
+    private static UpstreamNetworkState buildMobile464xlatUpstreamState() {
+        return buildMobileUpstreamState(false, true, true);
+    }
+
+    // See FakeSettingsProvider#clearSettingsProvider() that this needs to be called before and
+    // after use.
+    @BeforeClass
+    public static void setupOnce() {
+        FakeSettingsProvider.clearSettingsProvider();
+    }
+
+    @AfterClass
+    public static void tearDownOnce() {
+        FakeSettingsProvider.clearSettingsProvider();
+    }
+
+    @Before
+    public void setUp() throws Exception {
+        MockitoAnnotations.initMocks(this);
+        when(mResources.getStringArray(R.array.config_tether_dhcp_range))
+                .thenReturn(new String[0]);
+        when(mResources.getBoolean(R.bool.config_tether_enable_legacy_dhcp_server)).thenReturn(
+                false);
+        when(mNetd.interfaceGetList())
+                .thenReturn(new String[] {
+                        TEST_MOBILE_IFNAME, TEST_WLAN_IFNAME, TEST_USB_IFNAME, TEST_P2P_IFNAME,
+                        TEST_NCM_IFNAME, TEST_ETH_IFNAME});
+        when(mResources.getString(R.string.config_wifi_tether_enable)).thenReturn("");
+        mInterfaceConfiguration = new InterfaceConfigurationParcel();
+        mInterfaceConfiguration.flags = new String[0];
+        when(mRouterAdvertisementDaemon.start())
+                .thenReturn(true);
+        initOffloadConfiguration(true /* offloadConfig */, true /* offloadControl */,
+                0 /* defaultDisabled */);
+        when(mOffloadHardwareInterface.getForwardedStats(any())).thenReturn(mForwardedStats);
+
+        mServiceContext = new TestContext(mContext);
+        mContentResolver = new MockContentResolver(mServiceContext);
+        mContentResolver.addProvider(Settings.AUTHORITY, new FakeSettingsProvider());
+        setTetheringSupported(true /* supported */);
+        mIntents = new Vector<>();
+        mBroadcastReceiver = new BroadcastReceiver() {
+            @Override
+            public void onReceive(Context context, Intent intent) {
+                mIntents.addElement(intent);
+            }
+        };
+        mServiceContext.registerReceiver(mBroadcastReceiver,
+                new IntentFilter(ACTION_TETHER_STATE_CHANGED));
+        mTethering = makeTethering();
+        verify(mStatsManager, times(1)).registerNetworkStatsProvider(anyString(), any());
+        verify(mNetd).registerUnsolicitedEventListener(any());
+        final ArgumentCaptor<PhoneStateListener> phoneListenerCaptor =
+                ArgumentCaptor.forClass(PhoneStateListener.class);
+        verify(mTelephonyManager).listen(phoneListenerCaptor.capture(),
+                eq(PhoneStateListener.LISTEN_ACTIVE_DATA_SUBSCRIPTION_ID_CHANGE));
+        verify(mWifiManager).registerSoftApCallback(any(), any());
+        mPhoneStateListener = phoneListenerCaptor.getValue();
+    }
+
+    private void setTetheringSupported(final boolean supported) {
+        Settings.Global.putInt(mContentResolver, Settings.Global.TETHER_SUPPORTED,
+                supported ? 1 : 0);
+        when(mUserManager.hasUserRestriction(
+                UserManager.DISALLOW_CONFIG_TETHERING)).thenReturn(!supported);
+        // Setup tetherable configuration.
+        when(mResources.getStringArray(R.array.config_tether_usb_regexs))
+                .thenReturn(new String[] { "test_rndis\\d" });
+        when(mResources.getStringArray(R.array.config_tether_wifi_regexs))
+                .thenReturn(new String[]{ "test_wlan\\d" });
+        when(mResources.getStringArray(R.array.config_tether_wifi_p2p_regexs))
+                .thenReturn(new String[]{ "test_p2p-p2p\\d-.*" });
+        when(mResources.getStringArray(R.array.config_tether_bluetooth_regexs))
+                .thenReturn(new String[0]);
+        when(mResources.getStringArray(R.array.config_tether_ncm_regexs))
+                .thenReturn(new String[] { "test_ncm\\d" });
+        when(mResources.getIntArray(R.array.config_tether_upstream_types)).thenReturn(new int[0]);
+        when(mResources.getBoolean(R.bool.config_tether_upstream_automatic)).thenReturn(true);
+    }
+
+    private void initTetheringUpstream(UpstreamNetworkState upstreamState) {
+        when(mUpstreamNetworkMonitor.getCurrentPreferredUpstream()).thenReturn(upstreamState);
+        when(mUpstreamNetworkMonitor.selectPreferredUpstreamType(any())).thenReturn(upstreamState);
+    }
+
+    private Tethering makeTethering() {
+        mTetheringDependencies.reset();
+        return new Tethering(mTetheringDependencies);
+    }
+
+    private TetheringRequestParcel createTetheringRequestParcel(final int type) {
+        return createTetheringRequestParcel(type, null, null, false);
+    }
+
+    private TetheringRequestParcel createTetheringRequestParcel(final int type,
+            final LinkAddress serverAddr, final LinkAddress clientAddr, final boolean exempt) {
+        final TetheringRequestParcel request = new TetheringRequestParcel();
+        request.tetheringType = type;
+        request.localIPv4Address = serverAddr;
+        request.staticClientAddress = clientAddr;
+        request.exemptFromEntitlementCheck = exempt;
+        request.showProvisioningUi = false;
+
+        return request;
+    }
+
+    @After
+    public void tearDown() {
+        mServiceContext.unregisterReceiver(mBroadcastReceiver);
+    }
+
+    private void sendWifiApStateChanged(int state) {
+        final Intent intent = new Intent(WifiManager.WIFI_AP_STATE_CHANGED_ACTION);
+        intent.putExtra(EXTRA_WIFI_AP_STATE, state);
+        mServiceContext.sendStickyBroadcastAsUser(intent, UserHandle.ALL);
+    }
+
+    private void sendWifiApStateChanged(int state, String ifname, int ipmode) {
+        final Intent intent = new Intent(WifiManager.WIFI_AP_STATE_CHANGED_ACTION);
+        intent.putExtra(EXTRA_WIFI_AP_STATE, state);
+        intent.putExtra(EXTRA_WIFI_AP_INTERFACE_NAME, ifname);
+        intent.putExtra(EXTRA_WIFI_AP_MODE, ipmode);
+        mServiceContext.sendStickyBroadcastAsUser(intent, UserHandle.ALL);
+    }
+
+    private static final String[] P2P_RECEIVER_PERMISSIONS_FOR_BROADCAST = {
+            android.Manifest.permission.ACCESS_FINE_LOCATION,
+            android.Manifest.permission.ACCESS_WIFI_STATE
+    };
+
+    private void sendWifiP2pConnectionChanged(
+            boolean isGroupFormed, boolean isGroupOwner, String ifname) {
+        WifiP2pGroup group = null;
+        WifiP2pInfo p2pInfo = new WifiP2pInfo();
+        p2pInfo.groupFormed = isGroupFormed;
+        if (isGroupFormed) {
+            p2pInfo.isGroupOwner = isGroupOwner;
+            group = mock(WifiP2pGroup.class);
+            when(group.isGroupOwner()).thenReturn(isGroupOwner);
+            when(group.getInterface()).thenReturn(ifname);
+        }
+
+        final Intent intent = mock(Intent.class);
+        when(intent.getAction()).thenReturn(WifiP2pManager.WIFI_P2P_CONNECTION_CHANGED_ACTION);
+        when(intent.getParcelableExtra(WifiP2pManager.EXTRA_WIFI_P2P_INFO)).thenReturn(p2pInfo);
+        when(intent.getParcelableExtra(WifiP2pManager.EXTRA_WIFI_P2P_GROUP)).thenReturn(group);
+
+        mServiceContext.sendBroadcastAsUserMultiplePermissions(intent, UserHandle.ALL,
+                P2P_RECEIVER_PERMISSIONS_FOR_BROADCAST);
+    }
+
+    private void sendUsbBroadcast(boolean connected, boolean configured, boolean function,
+            int type) {
+        final Intent intent = new Intent(UsbManager.ACTION_USB_STATE);
+        intent.putExtra(USB_CONNECTED, connected);
+        intent.putExtra(USB_CONFIGURED, configured);
+        if (type == TETHERING_USB) {
+            intent.putExtra(USB_FUNCTION_RNDIS, function);
+        } else {
+            intent.putExtra(USB_FUNCTION_NCM, function);
+        }
+        mServiceContext.sendStickyBroadcastAsUser(intent, UserHandle.ALL);
+    }
+
+    private void sendConfigurationChanged() {
+        final Intent intent = new Intent(Intent.ACTION_CONFIGURATION_CHANGED);
+        mServiceContext.sendStickyBroadcastAsUser(intent, UserHandle.ALL);
+    }
+
+    private void verifyInterfaceServingModeStarted(String ifname) throws Exception {
+        verify(mNetd, times(1)).interfaceSetCfg(any(InterfaceConfigurationParcel.class));
+        verify(mNetd, times(1)).tetherInterfaceAdd(ifname);
+        verify(mNetd, times(1)).networkAddInterface(INetd.LOCAL_NET_ID, ifname);
+        verify(mNetd, times(2)).networkAddRoute(eq(INetd.LOCAL_NET_ID), eq(ifname),
+                anyString(), anyString());
+    }
+
+    private void verifyTetheringBroadcast(String ifname, String whichExtra) {
+        // Verify that ifname is in the whichExtra array of the tether state changed broadcast.
+        final Intent bcast = mIntents.get(0);
+        assertEquals(ACTION_TETHER_STATE_CHANGED, bcast.getAction());
+        final ArrayList<String> ifnames = bcast.getStringArrayListExtra(whichExtra);
+        assertTrue(ifnames.contains(ifname));
+        mIntents.remove(bcast);
+    }
+
+    public void failingLocalOnlyHotspotLegacyApBroadcast(
+            boolean emulateInterfaceStatusChanged) throws Exception {
+        // Emulate externally-visible WifiManager effects, causing the
+        // per-interface state machine to start up, and telling us that
+        // hotspot mode is to be started.
+        if (emulateInterfaceStatusChanged) {
+            mTethering.interfaceStatusChanged(TEST_WLAN_IFNAME, true);
+        }
+        sendWifiApStateChanged(WIFI_AP_STATE_ENABLED);
+        mLooper.dispatchAll();
+
+        // If, and only if, Tethering received an interface status changed then
+        // it creates a IpServer and sends out a broadcast indicating that the
+        // interface is "available".
+        if (emulateInterfaceStatusChanged) {
+            // There is 1 IpServer state change event: STATE_AVAILABLE
+            verify(mNotificationUpdater, times(1)).onDownstreamChanged(DOWNSTREAM_NONE);
+            verifyTetheringBroadcast(TEST_WLAN_IFNAME, EXTRA_AVAILABLE_TETHER);
+            verify(mWifiManager).updateInterfaceIpState(
+                    TEST_WLAN_IFNAME, WifiManager.IFACE_IP_MODE_UNSPECIFIED);
+        }
+        verifyNoMoreInteractions(mNetd);
+        verifyNoMoreInteractions(mWifiManager);
+    }
+
+    private void prepareNcmTethering() {
+        // Emulate startTethering(TETHERING_NCM) called
+        mTethering.startTethering(createTetheringRequestParcel(TETHERING_NCM), null);
+        mLooper.dispatchAll();
+        verify(mUsbManager, times(1)).setCurrentFunctions(UsbManager.FUNCTION_NCM);
+
+        mTethering.interfaceStatusChanged(TEST_NCM_IFNAME, true);
+    }
+
+    private void prepareUsbTethering(UpstreamNetworkState upstreamState) {
+        initTetheringUpstream(upstreamState);
+
+        // Emulate pressing the USB tethering button in Settings UI.
+        mTethering.startTethering(createTetheringRequestParcel(TETHERING_USB), null);
+        mLooper.dispatchAll();
+        verify(mUsbManager, times(1)).setCurrentFunctions(UsbManager.FUNCTION_RNDIS);
+
+        mTethering.interfaceStatusChanged(TEST_USB_IFNAME, true);
+    }
+
+    @Test
+    public void testUsbConfiguredBroadcastStartsTethering() throws Exception {
+        UpstreamNetworkState upstreamState = buildMobileIPv4UpstreamState();
+        prepareUsbTethering(upstreamState);
+
+        // This should produce no activity of any kind.
+        verifyNoMoreInteractions(mNetd);
+
+        // Pretend we then receive USB configured broadcast.
+        sendUsbBroadcast(true, true, true, TETHERING_USB);
+        mLooper.dispatchAll();
+        // Now we should see the start of tethering mechanics (in this case:
+        // tetherMatchingInterfaces() which starts by fetching all interfaces).
+        verify(mNetd, times(1)).interfaceGetList();
+
+        // UpstreamNetworkMonitor should receive selected upstream
+        verify(mUpstreamNetworkMonitor, times(1)).getCurrentPreferredUpstream();
+        verify(mUpstreamNetworkMonitor, times(1)).setCurrentUpstream(upstreamState.network);
+    }
+
+    @Test
+    public void failingLocalOnlyHotspotLegacyApBroadcastWithIfaceStatusChanged() throws Exception {
+        failingLocalOnlyHotspotLegacyApBroadcast(true);
+    }
+
+    @Test
+    public void failingLocalOnlyHotspotLegacyApBroadcastSansIfaceStatusChanged() throws Exception {
+        failingLocalOnlyHotspotLegacyApBroadcast(false);
+    }
+
+    public void workingLocalOnlyHotspotEnrichedApBroadcast(
+            boolean emulateInterfaceStatusChanged) throws Exception {
+        // Emulate externally-visible WifiManager effects, causing the
+        // per-interface state machine to start up, and telling us that
+        // hotspot mode is to be started.
+        if (emulateInterfaceStatusChanged) {
+            mTethering.interfaceStatusChanged(TEST_WLAN_IFNAME, true);
+        }
+        sendWifiApStateChanged(WIFI_AP_STATE_ENABLED, TEST_WLAN_IFNAME, IFACE_IP_MODE_LOCAL_ONLY);
+        mLooper.dispatchAll();
+
+        verifyInterfaceServingModeStarted(TEST_WLAN_IFNAME);
+        verifyTetheringBroadcast(TEST_WLAN_IFNAME, EXTRA_AVAILABLE_TETHER);
+        verify(mNetd, times(1)).ipfwdEnableForwarding(TETHERING_NAME);
+        verify(mNetd, times(1)).tetherStartWithConfiguration(any());
+        verifyNoMoreInteractions(mNetd);
+        verify(mWifiManager).updateInterfaceIpState(
+                TEST_WLAN_IFNAME, WifiManager.IFACE_IP_MODE_UNSPECIFIED);
+        verify(mWifiManager).updateInterfaceIpState(
+                TEST_WLAN_IFNAME, WifiManager.IFACE_IP_MODE_LOCAL_ONLY);
+        verifyNoMoreInteractions(mWifiManager);
+        verifyTetheringBroadcast(TEST_WLAN_IFNAME, EXTRA_ACTIVE_LOCAL_ONLY);
+        verify(mUpstreamNetworkMonitor, times(1)).startObserveAllNetworks();
+        // There are 2 IpServer state change events: STATE_AVAILABLE -> STATE_LOCAL_ONLY
+        verify(mNotificationUpdater, times(2)).onDownstreamChanged(DOWNSTREAM_NONE);
+
+        // Emulate externally-visible WifiManager effects, when hotspot mode
+        // is being torn down.
+        sendWifiApStateChanged(WifiManager.WIFI_AP_STATE_DISABLED);
+        mTethering.interfaceRemoved(TEST_WLAN_IFNAME);
+        mLooper.dispatchAll();
+
+        verify(mNetd, times(1)).tetherApplyDnsInterfaces();
+        verify(mNetd, times(1)).tetherInterfaceRemove(TEST_WLAN_IFNAME);
+        verify(mNetd, times(1)).networkRemoveInterface(INetd.LOCAL_NET_ID, TEST_WLAN_IFNAME);
+        // interfaceSetCfg() called once for enabling and twice disabling IPv4.
+        verify(mNetd, times(3)).interfaceSetCfg(any(InterfaceConfigurationParcel.class));
+        verify(mNetd, times(1)).tetherStop();
+        verify(mNetd, times(1)).ipfwdDisableForwarding(TETHERING_NAME);
+        verify(mWifiManager, times(3)).updateInterfaceIpState(
+                TEST_WLAN_IFNAME, WifiManager.IFACE_IP_MODE_UNSPECIFIED);
+        verifyNoMoreInteractions(mNetd);
+        verifyNoMoreInteractions(mWifiManager);
+        // Asking for the last error after the per-interface state machine
+        // has been reaped yields an unknown interface error.
+        assertEquals(TETHER_ERROR_UNKNOWN_IFACE, mTethering.getLastTetherError(TEST_WLAN_IFNAME));
+    }
+
+    /**
+     * Send CMD_IPV6_TETHER_UPDATE to IpServers as would be done by IPv6TetheringCoordinator.
+     */
+    private void sendIPv6TetherUpdates(UpstreamNetworkState upstreamState) {
+        // IPv6TetheringCoordinator must have been notified of downstream
+        verify(mIPv6TetheringCoordinator, times(1)).addActiveDownstream(
+                argThat(sm -> sm.linkProperties().getInterfaceName().equals(TEST_USB_IFNAME)),
+                eq(IpServer.STATE_TETHERED));
+
+        for (IpServer ipSrv : mTetheringDependencies.mIpv6CoordinatorNotifyList) {
+            UpstreamNetworkState ipv6OnlyState = buildMobileUpstreamState(false, true, false);
+            ipSrv.sendMessage(IpServer.CMD_IPV6_TETHER_UPDATE, 0, 0,
+                    upstreamState.linkProperties.isIpv6Provisioned()
+                            ? ipv6OnlyState.linkProperties
+                            : null);
+        }
+        mLooper.dispatchAll();
+    }
+
+    private void runUsbTethering(UpstreamNetworkState upstreamState) {
+        prepareUsbTethering(upstreamState);
+        sendUsbBroadcast(true, true, true, TETHERING_USB);
+        mLooper.dispatchAll();
+    }
+
+    @Test
+    public void workingMobileUsbTethering_IPv4() throws Exception {
+        UpstreamNetworkState upstreamState = buildMobileIPv4UpstreamState();
+        runUsbTethering(upstreamState);
+
+        verify(mNetd, times(1)).tetherAddForward(TEST_USB_IFNAME, TEST_MOBILE_IFNAME);
+        verify(mNetd, times(1)).ipfwdAddInterfaceForward(TEST_USB_IFNAME, TEST_MOBILE_IFNAME);
+
+        sendIPv6TetherUpdates(upstreamState);
+        verify(mDadProxy, never()).setUpstreamIface(notNull());
+        verify(mRouterAdvertisementDaemon, never()).buildNewRa(any(), notNull());
+        verify(mDhcpServer, timeout(DHCPSERVER_START_TIMEOUT_MS).times(1)).startWithCallbacks(
+                any(), any());
+    }
+
+    @Test
+    public void workingMobileUsbTethering_IPv4LegacyDhcp() {
+        when(mResources.getBoolean(R.bool.config_tether_enable_legacy_dhcp_server)).thenReturn(
+                true);
+        sendConfigurationChanged();
+        final UpstreamNetworkState upstreamState = buildMobileIPv4UpstreamState();
+        runUsbTethering(upstreamState);
+        sendIPv6TetherUpdates(upstreamState);
+
+        verify(mIpServerDependencies, never()).makeDhcpServer(any(), any(), any());
+    }
+
+    @Test
+    public void workingMobileUsbTethering_IPv6() throws Exception {
+        UpstreamNetworkState upstreamState = buildMobileIPv6UpstreamState();
+        runUsbTethering(upstreamState);
+
+        verify(mNetd, times(1)).tetherAddForward(TEST_USB_IFNAME, TEST_MOBILE_IFNAME);
+        verify(mNetd, times(1)).ipfwdAddInterfaceForward(TEST_USB_IFNAME, TEST_MOBILE_IFNAME);
+
+        sendIPv6TetherUpdates(upstreamState);
+        // TODO: add interfaceParams to compare in verify.
+        verify(mDadProxy, times(1)).setUpstreamIface(notNull());
+        verify(mRouterAdvertisementDaemon, times(1)).buildNewRa(any(), notNull());
+        verify(mNetd, times(1)).tetherApplyDnsInterfaces();
+    }
+
+    @Test
+    public void workingMobileUsbTethering_DualStack() throws Exception {
+        UpstreamNetworkState upstreamState = buildMobileDualStackUpstreamState();
+        runUsbTethering(upstreamState);
+
+        verify(mNetd, times(1)).tetherAddForward(TEST_USB_IFNAME, TEST_MOBILE_IFNAME);
+        verify(mNetd, times(1)).ipfwdAddInterfaceForward(TEST_USB_IFNAME, TEST_MOBILE_IFNAME);
+        verify(mRouterAdvertisementDaemon, times(1)).start();
+        verify(mDhcpServer, timeout(DHCPSERVER_START_TIMEOUT_MS).times(1)).startWithCallbacks(
+                any(), any());
+
+        sendIPv6TetherUpdates(upstreamState);
+        verify(mDadProxy, times(1)).setUpstreamIface(notNull());
+        verify(mRouterAdvertisementDaemon, times(1)).buildNewRa(any(), notNull());
+        verify(mNetd, times(1)).tetherApplyDnsInterfaces();
+    }
+
+    @Test
+    public void workingMobileUsbTethering_MultipleUpstreams() throws Exception {
+        UpstreamNetworkState upstreamState = buildMobile464xlatUpstreamState();
+        runUsbTethering(upstreamState);
+
+        verify(mNetd, times(1)).tetherAddForward(TEST_USB_IFNAME, TEST_XLAT_MOBILE_IFNAME);
+        verify(mNetd, times(1)).tetherAddForward(TEST_USB_IFNAME, TEST_MOBILE_IFNAME);
+        verify(mDhcpServer, timeout(DHCPSERVER_START_TIMEOUT_MS).times(1)).startWithCallbacks(
+                any(), any());
+        verify(mNetd, times(1)).ipfwdAddInterfaceForward(TEST_USB_IFNAME, TEST_XLAT_MOBILE_IFNAME);
+        verify(mNetd, times(1)).ipfwdAddInterfaceForward(TEST_USB_IFNAME, TEST_MOBILE_IFNAME);
+
+        sendIPv6TetherUpdates(upstreamState);
+        verify(mDadProxy, times(1)).setUpstreamIface(notNull());
+        verify(mRouterAdvertisementDaemon, times(1)).buildNewRa(any(), notNull());
+        verify(mNetd, times(1)).tetherApplyDnsInterfaces();
+    }
+
+    @Test
+    public void workingMobileUsbTethering_v6Then464xlat() throws Exception {
+        // Setup IPv6
+        UpstreamNetworkState upstreamState = buildMobileIPv6UpstreamState();
+        runUsbTethering(upstreamState);
+
+        verify(mNetd, times(1)).tetherAddForward(TEST_USB_IFNAME, TEST_MOBILE_IFNAME);
+        verify(mDhcpServer, timeout(DHCPSERVER_START_TIMEOUT_MS).times(1)).startWithCallbacks(
+                any(), any());
+        verify(mNetd, times(1)).ipfwdAddInterfaceForward(TEST_USB_IFNAME, TEST_MOBILE_IFNAME);
+
+        // Then 464xlat comes up
+        upstreamState = buildMobile464xlatUpstreamState();
+        initTetheringUpstream(upstreamState);
+
+        // Upstream LinkProperties changed: UpstreamNetworkMonitor sends EVENT_ON_LINKPROPERTIES.
+        mTetheringDependencies.mUpstreamNetworkMonitorSM.sendMessage(
+                Tethering.TetherMainSM.EVENT_UPSTREAM_CALLBACK,
+                UpstreamNetworkMonitor.EVENT_ON_LINKPROPERTIES,
+                0,
+                upstreamState);
+        mLooper.dispatchAll();
+
+        // Forwarding is added for 464xlat
+        verify(mNetd, times(1)).tetherAddForward(TEST_USB_IFNAME, TEST_XLAT_MOBILE_IFNAME);
+        verify(mNetd, times(1)).ipfwdAddInterfaceForward(TEST_USB_IFNAME, TEST_XLAT_MOBILE_IFNAME);
+        // Forwarding was not re-added for v6 (still times(1))
+        verify(mNetd, times(1)).tetherAddForward(TEST_USB_IFNAME, TEST_MOBILE_IFNAME);
+        verify(mNetd, times(1)).ipfwdAddInterfaceForward(TEST_USB_IFNAME, TEST_MOBILE_IFNAME);
+        // DHCP not restarted on downstream (still times(1))
+        verify(mDhcpServer, timeout(DHCPSERVER_START_TIMEOUT_MS).times(1)).startWithCallbacks(
+                any(), any());
+    }
+
+    @Test
+    public void configTetherUpstreamAutomaticIgnoresConfigTetherUpstreamTypes() throws Exception {
+        when(mResources.getBoolean(R.bool.config_tether_upstream_automatic)).thenReturn(true);
+        sendConfigurationChanged();
+
+        // Setup IPv6
+        final UpstreamNetworkState upstreamState = buildMobileIPv6UpstreamState();
+        runUsbTethering(upstreamState);
+
+        // UpstreamNetworkMonitor should choose upstream automatically
+        // (in this specific case: choose the default network).
+        verify(mUpstreamNetworkMonitor, times(1)).getCurrentPreferredUpstream();
+        verify(mUpstreamNetworkMonitor, never()).selectPreferredUpstreamType(any());
+
+        verify(mUpstreamNetworkMonitor, times(1)).setCurrentUpstream(upstreamState.network);
+    }
+
+    private void runNcmTethering() {
+        prepareNcmTethering();
+        sendUsbBroadcast(true, true, true, TETHERING_NCM);
+        mLooper.dispatchAll();
+    }
+
+    @Test
+    public void workingNcmTethering() throws Exception {
+        runNcmTethering();
+
+        verify(mDhcpServer, timeout(DHCPSERVER_START_TIMEOUT_MS).times(1)).startWithCallbacks(
+                any(), any());
+    }
+
+    @Test
+    public void workingNcmTethering_LegacyDhcp() {
+        when(mResources.getBoolean(R.bool.config_tether_enable_legacy_dhcp_server)).thenReturn(
+                true);
+        sendConfigurationChanged();
+        runNcmTethering();
+
+        verify(mIpServerDependencies, never()).makeDhcpServer(any(), any(), any());
+    }
+
+    @Test
+    public void workingLocalOnlyHotspotEnrichedApBroadcastWithIfaceChanged() throws Exception {
+        workingLocalOnlyHotspotEnrichedApBroadcast(true);
+    }
+
+    @Test
+    public void workingLocalOnlyHotspotEnrichedApBroadcastSansIfaceChanged() throws Exception {
+        workingLocalOnlyHotspotEnrichedApBroadcast(false);
+    }
+
+    // TODO: Test with and without interfaceStatusChanged().
+    @Test
+    public void failingWifiTetheringLegacyApBroadcast() throws Exception {
+        when(mWifiManager.startTetheredHotspot(any(SoftApConfiguration.class))).thenReturn(true);
+
+        // Emulate pressing the WiFi tethering button.
+        mTethering.startTethering(createTetheringRequestParcel(TETHERING_WIFI), null);
+        mLooper.dispatchAll();
+        verify(mWifiManager, times(1)).startTetheredHotspot(null);
+        verifyNoMoreInteractions(mWifiManager);
+        verifyNoMoreInteractions(mNetd);
+
+        // Emulate externally-visible WifiManager effects, causing the
+        // per-interface state machine to start up, and telling us that
+        // tethering mode is to be started.
+        mTethering.interfaceStatusChanged(TEST_WLAN_IFNAME, true);
+        sendWifiApStateChanged(WIFI_AP_STATE_ENABLED);
+        mLooper.dispatchAll();
+
+        // There is 1 IpServer state change event: STATE_AVAILABLE
+        verify(mNotificationUpdater, times(1)).onDownstreamChanged(DOWNSTREAM_NONE);
+        verifyTetheringBroadcast(TEST_WLAN_IFNAME, EXTRA_AVAILABLE_TETHER);
+        verify(mWifiManager).updateInterfaceIpState(
+                TEST_WLAN_IFNAME, WifiManager.IFACE_IP_MODE_UNSPECIFIED);
+        verifyNoMoreInteractions(mNetd);
+        verifyNoMoreInteractions(mWifiManager);
+    }
+
+    // TODO: Test with and without interfaceStatusChanged().
+    @Test
+    public void workingWifiTetheringEnrichedApBroadcast() throws Exception {
+        when(mWifiManager.startTetheredHotspot(any(SoftApConfiguration.class))).thenReturn(true);
+
+        // Emulate pressing the WiFi tethering button.
+        mTethering.startTethering(createTetheringRequestParcel(TETHERING_WIFI), null);
+        mLooper.dispatchAll();
+        verify(mWifiManager, times(1)).startTetheredHotspot(null);
+        verifyNoMoreInteractions(mWifiManager);
+        verifyNoMoreInteractions(mNetd);
+
+        // Emulate externally-visible WifiManager effects, causing the
+        // per-interface state machine to start up, and telling us that
+        // tethering mode is to be started.
+        mTethering.interfaceStatusChanged(TEST_WLAN_IFNAME, true);
+        sendWifiApStateChanged(WIFI_AP_STATE_ENABLED, TEST_WLAN_IFNAME, IFACE_IP_MODE_TETHERED);
+        mLooper.dispatchAll();
+
+        verifyInterfaceServingModeStarted(TEST_WLAN_IFNAME);
+        verifyTetheringBroadcast(TEST_WLAN_IFNAME, EXTRA_AVAILABLE_TETHER);
+        verify(mNetd, times(1)).ipfwdEnableForwarding(TETHERING_NAME);
+        verify(mNetd, times(1)).tetherStartWithConfiguration(any());
+        verify(mNetd, times(2)).networkAddRoute(eq(INetd.LOCAL_NET_ID), eq(TEST_WLAN_IFNAME),
+                anyString(), anyString());
+        verifyNoMoreInteractions(mNetd);
+        verify(mWifiManager).updateInterfaceIpState(
+                TEST_WLAN_IFNAME, WifiManager.IFACE_IP_MODE_UNSPECIFIED);
+        verify(mWifiManager).updateInterfaceIpState(
+                TEST_WLAN_IFNAME, WifiManager.IFACE_IP_MODE_TETHERED);
+        verifyNoMoreInteractions(mWifiManager);
+        verifyTetheringBroadcast(TEST_WLAN_IFNAME, EXTRA_ACTIVE_TETHER);
+        verify(mUpstreamNetworkMonitor, times(1)).startObserveAllNetworks();
+        // In tethering mode, in the default configuration, an explicit request
+        // for a mobile network is also made.
+        verify(mUpstreamNetworkMonitor, times(1)).registerMobileNetworkRequest();
+        // There are 2 IpServer state change events: STATE_AVAILABLE -> STATE_TETHERED
+        verify(mNotificationUpdater, times(1)).onDownstreamChanged(DOWNSTREAM_NONE);
+        verify(mNotificationUpdater, times(1)).onDownstreamChanged(eq(1 << TETHERING_WIFI));
+
+        /////
+        // We do not currently emulate any upstream being found.
+        //
+        // This is why there are no calls to verify mNetd.tetherAddForward() or
+        // mNetd.ipfwdAddInterfaceForward().
+        /////
+
+        // Emulate pressing the WiFi tethering button.
+        mTethering.stopTethering(TETHERING_WIFI);
+        mLooper.dispatchAll();
+        verify(mWifiManager, times(1)).stopSoftAp();
+        verifyNoMoreInteractions(mWifiManager);
+        verifyNoMoreInteractions(mNetd);
+
+        // Emulate externally-visible WifiManager effects, when tethering mode
+        // is being torn down.
+        sendWifiApStateChanged(WifiManager.WIFI_AP_STATE_DISABLED);
+        mTethering.interfaceRemoved(TEST_WLAN_IFNAME);
+        mLooper.dispatchAll();
+
+        verify(mNetd, times(1)).tetherApplyDnsInterfaces();
+        verify(mNetd, times(1)).tetherInterfaceRemove(TEST_WLAN_IFNAME);
+        verify(mNetd, times(1)).networkRemoveInterface(INetd.LOCAL_NET_ID, TEST_WLAN_IFNAME);
+        // interfaceSetCfg() called once for enabling and twice for disabling IPv4.
+        verify(mNetd, times(3)).interfaceSetCfg(any(InterfaceConfigurationParcel.class));
+        verify(mNetd, times(1)).tetherStop();
+        verify(mNetd, times(1)).ipfwdDisableForwarding(TETHERING_NAME);
+        verify(mWifiManager, times(3)).updateInterfaceIpState(
+                TEST_WLAN_IFNAME, WifiManager.IFACE_IP_MODE_UNSPECIFIED);
+        verifyNoMoreInteractions(mNetd);
+        verifyNoMoreInteractions(mWifiManager);
+        // Asking for the last error after the per-interface state machine
+        // has been reaped yields an unknown interface error.
+        assertEquals(TETHER_ERROR_UNKNOWN_IFACE, mTethering.getLastTetherError(TEST_WLAN_IFNAME));
+    }
+
+    // TODO: Test with and without interfaceStatusChanged().
+    @Test
+    public void failureEnablingIpForwarding() throws Exception {
+        when(mWifiManager.startTetheredHotspot(any(SoftApConfiguration.class))).thenReturn(true);
+        doThrow(new RemoteException()).when(mNetd).ipfwdEnableForwarding(TETHERING_NAME);
+
+        // Emulate pressing the WiFi tethering button.
+        mTethering.startTethering(createTetheringRequestParcel(TETHERING_WIFI), null);
+        mLooper.dispatchAll();
+        verify(mWifiManager, times(1)).startTetheredHotspot(null);
+        verifyNoMoreInteractions(mWifiManager);
+        verifyNoMoreInteractions(mNetd);
+
+        // Emulate externally-visible WifiManager effects, causing the
+        // per-interface state machine to start up, and telling us that
+        // tethering mode is to be started.
+        mTethering.interfaceStatusChanged(TEST_WLAN_IFNAME, true);
+        sendWifiApStateChanged(WIFI_AP_STATE_ENABLED, TEST_WLAN_IFNAME, IFACE_IP_MODE_TETHERED);
+        mLooper.dispatchAll();
+
+        // We verify get/set called three times here: twice for setup and once during
+        // teardown because all events happen over the course of the single
+        // dispatchAll() above. Note that once the IpServer IPv4 address config
+        // code is refactored the two calls during shutdown will revert to one.
+        verify(mNetd, times(3)).interfaceSetCfg(argThat(p -> TEST_WLAN_IFNAME.equals(p.ifName)));
+        verify(mNetd, times(1)).tetherInterfaceAdd(TEST_WLAN_IFNAME);
+        verify(mNetd, times(1)).networkAddInterface(INetd.LOCAL_NET_ID, TEST_WLAN_IFNAME);
+        verify(mNetd, times(2)).networkAddRoute(eq(INetd.LOCAL_NET_ID), eq(TEST_WLAN_IFNAME),
+                anyString(), anyString());
+        verify(mWifiManager).updateInterfaceIpState(
+                TEST_WLAN_IFNAME, WifiManager.IFACE_IP_MODE_UNSPECIFIED);
+        verify(mWifiManager).updateInterfaceIpState(
+                TEST_WLAN_IFNAME, WifiManager.IFACE_IP_MODE_TETHERED);
+        // There are 3 IpServer state change event:
+        //         STATE_AVAILABLE -> STATE_TETHERED -> STATE_AVAILABLE.
+        verify(mNotificationUpdater, times(2)).onDownstreamChanged(DOWNSTREAM_NONE);
+        verify(mNotificationUpdater, times(1)).onDownstreamChanged(eq(1 << TETHERING_WIFI));
+        verifyTetheringBroadcast(TEST_WLAN_IFNAME, EXTRA_AVAILABLE_TETHER);
+        // This is called, but will throw.
+        verify(mNetd, times(1)).ipfwdEnableForwarding(TETHERING_NAME);
+        // This never gets called because of the exception thrown above.
+        verify(mNetd, times(0)).tetherStartWithConfiguration(any());
+        // When the main state machine transitions to an error state it tells
+        // downstream interfaces, which causes us to tell Wi-Fi about the error
+        // so it can take down AP mode.
+        verify(mNetd, times(1)).tetherApplyDnsInterfaces();
+        verify(mNetd, times(1)).tetherInterfaceRemove(TEST_WLAN_IFNAME);
+        verify(mNetd, times(1)).networkRemoveInterface(INetd.LOCAL_NET_ID, TEST_WLAN_IFNAME);
+        verify(mWifiManager).updateInterfaceIpState(
+                TEST_WLAN_IFNAME, WifiManager.IFACE_IP_MODE_CONFIGURATION_ERROR);
+
+        verifyNoMoreInteractions(mWifiManager);
+        verifyNoMoreInteractions(mNetd);
+    }
+
+    private void runUserRestrictionsChange(
+            boolean currentDisallow, boolean nextDisallow, boolean isTetheringActive,
+            int expectedInteractionsWithShowNotification) throws  Exception {
+        final Bundle newRestrictions = new Bundle();
+        newRestrictions.putBoolean(UserManager.DISALLOW_CONFIG_TETHERING, nextDisallow);
+        final Tethering mockTethering = mock(Tethering.class);
+        when(mockTethering.isTetheringActive()).thenReturn(isTetheringActive);
+        when(mUserManager.getUserRestrictions()).thenReturn(newRestrictions);
+
+        final Tethering.UserRestrictionActionListener ural =
+                new Tethering.UserRestrictionActionListener(
+                        mUserManager, mockTethering, mNotificationUpdater);
+        ural.mDisallowTethering = currentDisallow;
+
+        ural.onUserRestrictionsChanged();
+
+        verify(mNotificationUpdater, times(expectedInteractionsWithShowNotification))
+                .notifyTetheringDisabledByRestriction();
+        verify(mockTethering, times(expectedInteractionsWithShowNotification)).untetherAll();
+    }
+
+    @Test
+    public void testDisallowTetheringWhenTetheringIsNotActive() throws Exception {
+        final boolean isTetheringActive = false;
+        final boolean currDisallow = false;
+        final boolean nextDisallow = true;
+        final int expectedInteractionsWithShowNotification = 0;
+
+        runUserRestrictionsChange(currDisallow, nextDisallow, isTetheringActive,
+                expectedInteractionsWithShowNotification);
+    }
+
+    @Test
+    public void testDisallowTetheringWhenTetheringIsActive() throws Exception {
+        final boolean isTetheringActive = true;
+        final boolean currDisallow = false;
+        final boolean nextDisallow = true;
+        final int expectedInteractionsWithShowNotification = 1;
+
+        runUserRestrictionsChange(currDisallow, nextDisallow, isTetheringActive,
+                expectedInteractionsWithShowNotification);
+    }
+
+    @Test
+    public void testAllowTetheringWhenTetheringIsNotActive() throws Exception {
+        final boolean isTetheringActive = false;
+        final boolean currDisallow = true;
+        final boolean nextDisallow = false;
+        final int expectedInteractionsWithShowNotification = 0;
+
+        runUserRestrictionsChange(currDisallow, nextDisallow, isTetheringActive,
+                expectedInteractionsWithShowNotification);
+    }
+
+    @Test
+    public void testAllowTetheringWhenTetheringIsActive() throws Exception {
+        final boolean isTetheringActive = true;
+        final boolean currDisallow = true;
+        final boolean nextDisallow = false;
+        final int expectedInteractionsWithShowNotification = 0;
+
+        runUserRestrictionsChange(currDisallow, nextDisallow, isTetheringActive,
+                expectedInteractionsWithShowNotification);
+    }
+
+    @Test
+    public void testDisallowTetheringUnchanged() throws Exception {
+        final boolean isTetheringActive = true;
+        final int expectedInteractionsWithShowNotification = 0;
+        boolean currDisallow = true;
+        boolean nextDisallow = true;
+
+        runUserRestrictionsChange(currDisallow, nextDisallow, isTetheringActive,
+                expectedInteractionsWithShowNotification);
+
+        currDisallow = false;
+        nextDisallow = false;
+
+        runUserRestrictionsChange(currDisallow, nextDisallow, isTetheringActive,
+                expectedInteractionsWithShowNotification);
+    }
+
+    private class TestTetheringEventCallback extends ITetheringEventCallback.Stub {
+        private final ArrayList<Network> mActualUpstreams = new ArrayList<>();
+        private final ArrayList<TetheringConfigurationParcel> mTetheringConfigs =
+                new ArrayList<>();
+        private final ArrayList<TetherStatesParcel> mTetherStates = new ArrayList<>();
+        private final ArrayList<Integer> mOffloadStatus = new ArrayList<>();
+
+        // This function will remove the recorded callbacks, so it must be called once for
+        // each callback. If this is called after multiple callback, the order matters.
+        // onCallbackCreated counts as the first call to expectUpstreamChanged with
+        // @see onCallbackCreated.
+        public void expectUpstreamChanged(Network... networks) {
+            if (networks == null) {
+                assertNoUpstreamChangeCallback();
+                return;
+            }
+
+            final ArrayList<Network> expectedUpstreams =
+                    new ArrayList<Network>(Arrays.asList(networks));
+            for (Network upstream : expectedUpstreams) {
+                // throws OOB if no expectations
+                assertEquals(mActualUpstreams.remove(0), upstream);
+            }
+            assertNoUpstreamChangeCallback();
+        }
+
+        // This function will remove the recorded callbacks, so it must be called once
+        // for each callback. If this is called after multiple callback, the order matters.
+        // onCallbackCreated counts as the first call to onConfigurationChanged with
+        // @see onCallbackCreated.
+        public void expectConfigurationChanged(TetheringConfigurationParcel... tetherConfigs) {
+            final ArrayList<TetheringConfigurationParcel> expectedTetherConfig =
+                    new ArrayList<TetheringConfigurationParcel>(Arrays.asList(tetherConfigs));
+            for (TetheringConfigurationParcel config : expectedTetherConfig) {
+                // throws OOB if no expectations
+                final TetheringConfigurationParcel actualConfig = mTetheringConfigs.remove(0);
+                assertTetherConfigParcelEqual(actualConfig, config);
+            }
+            assertNoConfigChangeCallback();
+        }
+
+        public void expectOffloadStatusChanged(final int expectedStatus) {
+            assertOffloadStatusChangedCallback();
+            assertEquals(mOffloadStatus.remove(0), new Integer(expectedStatus));
+        }
+
+        public TetherStatesParcel pollTetherStatesChanged() {
+            assertStateChangeCallback();
+            return mTetherStates.remove(0);
+        }
+
+        @Override
+        public void onUpstreamChanged(Network network) {
+            mActualUpstreams.add(network);
+        }
+
+        @Override
+        public void onConfigurationChanged(TetheringConfigurationParcel config) {
+            mTetheringConfigs.add(config);
+        }
+
+        @Override
+        public void onTetherStatesChanged(TetherStatesParcel states) {
+            mTetherStates.add(states);
+        }
+
+        @Override
+        public void onTetherClientsChanged(List<TetheredClient> clients) {
+            // TODO: check this
+        }
+
+        @Override
+        public void onOffloadStatusChanged(final int status) {
+            mOffloadStatus.add(status);
+        }
+
+        @Override
+        public void onCallbackStarted(TetheringCallbackStartedParcel parcel) {
+            mActualUpstreams.add(parcel.upstreamNetwork);
+            mTetheringConfigs.add(parcel.config);
+            mTetherStates.add(parcel.states);
+            mOffloadStatus.add(parcel.offloadStatus);
+        }
+
+        @Override
+        public void onCallbackStopped(int errorCode) { }
+
+        public void assertNoUpstreamChangeCallback() {
+            assertTrue(mActualUpstreams.isEmpty());
+        }
+
+        public void assertNoConfigChangeCallback() {
+            assertTrue(mTetheringConfigs.isEmpty());
+        }
+
+        public void assertNoStateChangeCallback() {
+            assertTrue(mTetherStates.isEmpty());
+        }
+
+        public void assertStateChangeCallback() {
+            assertFalse(mTetherStates.isEmpty());
+        }
+
+        public void assertOffloadStatusChangedCallback() {
+            assertFalse(mOffloadStatus.isEmpty());
+        }
+
+        public void assertNoCallback() {
+            assertNoUpstreamChangeCallback();
+            assertNoConfigChangeCallback();
+            assertNoStateChangeCallback();
+        }
+
+        private void assertTetherConfigParcelEqual(@NonNull TetheringConfigurationParcel actual,
+                @NonNull TetheringConfigurationParcel expect) {
+            assertEquals(actual.subId, expect.subId);
+            assertArrayEquals(actual.tetherableUsbRegexs, expect.tetherableUsbRegexs);
+            assertArrayEquals(actual.tetherableWifiRegexs, expect.tetherableWifiRegexs);
+            assertArrayEquals(actual.tetherableBluetoothRegexs, expect.tetherableBluetoothRegexs);
+            assertEquals(actual.isDunRequired, expect.isDunRequired);
+            assertEquals(actual.chooseUpstreamAutomatically, expect.chooseUpstreamAutomatically);
+            assertArrayEquals(actual.preferredUpstreamIfaceTypes,
+                    expect.preferredUpstreamIfaceTypes);
+            assertArrayEquals(actual.legacyDhcpRanges, expect.legacyDhcpRanges);
+            assertArrayEquals(actual.defaultIPv4DNS, expect.defaultIPv4DNS);
+            assertEquals(actual.enableLegacyDhcpServer, expect.enableLegacyDhcpServer);
+            assertArrayEquals(actual.provisioningApp, expect.provisioningApp);
+            assertEquals(actual.provisioningAppNoUi, expect.provisioningAppNoUi);
+            assertEquals(actual.provisioningCheckPeriod, expect.provisioningCheckPeriod);
+        }
+    }
+
+    private void assertTetherStatesNotNullButEmpty(final TetherStatesParcel parcel) {
+        assertFalse(parcel == null);
+        assertEquals(0, parcel.availableList.length);
+        assertEquals(0, parcel.tetheredList.length);
+        assertEquals(0, parcel.localOnlyList.length);
+        assertEquals(0, parcel.erroredIfaceList.length);
+        assertEquals(0, parcel.lastErrorList.length);
+        MiscAsserts.assertFieldCountEquals(5, TetherStatesParcel.class);
+    }
+
+    @Test
+    public void testRegisterTetheringEventCallback() throws Exception {
+        TestTetheringEventCallback callback = new TestTetheringEventCallback();
+        TestTetheringEventCallback callback2 = new TestTetheringEventCallback();
+
+        // 1. Register one callback before running any tethering.
+        mTethering.registerTetheringEventCallback(callback);
+        mLooper.dispatchAll();
+        callback.expectUpstreamChanged(new Network[] {null});
+        callback.expectConfigurationChanged(
+                mTethering.getTetheringConfiguration().toStableParcelable());
+        TetherStatesParcel tetherState = callback.pollTetherStatesChanged();
+        assertTetherStatesNotNullButEmpty(tetherState);
+        callback.expectOffloadStatusChanged(TETHER_HARDWARE_OFFLOAD_STOPPED);
+        // 2. Enable wifi tethering.
+        UpstreamNetworkState upstreamState = buildMobileDualStackUpstreamState();
+        initTetheringUpstream(upstreamState);
+        when(mWifiManager.startTetheredHotspot(any(SoftApConfiguration.class))).thenReturn(true);
+        mTethering.interfaceStatusChanged(TEST_WLAN_IFNAME, true);
+        mLooper.dispatchAll();
+        tetherState = callback.pollTetherStatesChanged();
+        assertArrayEquals(tetherState.availableList, new String[] {TEST_WLAN_IFNAME});
+
+        mTethering.startTethering(createTetheringRequestParcel(TETHERING_WIFI), null);
+        sendWifiApStateChanged(WIFI_AP_STATE_ENABLED, TEST_WLAN_IFNAME, IFACE_IP_MODE_TETHERED);
+        mLooper.dispatchAll();
+        tetherState = callback.pollTetherStatesChanged();
+        assertArrayEquals(tetherState.tetheredList, new String[] {TEST_WLAN_IFNAME});
+        callback.expectUpstreamChanged(upstreamState.network);
+        callback.expectOffloadStatusChanged(TETHER_HARDWARE_OFFLOAD_STARTED);
+
+        // 3. Register second callback.
+        mTethering.registerTetheringEventCallback(callback2);
+        mLooper.dispatchAll();
+        callback2.expectUpstreamChanged(upstreamState.network);
+        callback2.expectConfigurationChanged(
+                mTethering.getTetheringConfiguration().toStableParcelable());
+        tetherState = callback2.pollTetherStatesChanged();
+        assertEquals(tetherState.tetheredList, new String[] {TEST_WLAN_IFNAME});
+        callback2.expectOffloadStatusChanged(TETHER_HARDWARE_OFFLOAD_STARTED);
+
+        // 4. Unregister first callback and disable wifi tethering
+        mTethering.unregisterTetheringEventCallback(callback);
+        mLooper.dispatchAll();
+        mTethering.stopTethering(TETHERING_WIFI);
+        sendWifiApStateChanged(WifiManager.WIFI_AP_STATE_DISABLED);
+        mLooper.dispatchAll();
+        tetherState = callback2.pollTetherStatesChanged();
+        assertArrayEquals(tetherState.availableList, new String[] {TEST_WLAN_IFNAME});
+        mLooper.dispatchAll();
+        callback2.expectUpstreamChanged(new Network[] {null});
+        callback2.expectOffloadStatusChanged(TETHER_HARDWARE_OFFLOAD_STOPPED);
+        callback.assertNoCallback();
+    }
+
+    @Test
+    public void testReportFailCallbackIfOffloadNotSupported() throws Exception {
+        final UpstreamNetworkState upstreamState = buildMobileDualStackUpstreamState();
+        TestTetheringEventCallback callback = new TestTetheringEventCallback();
+        mTethering.registerTetheringEventCallback(callback);
+        mLooper.dispatchAll();
+        callback.expectOffloadStatusChanged(TETHER_HARDWARE_OFFLOAD_STOPPED);
+
+        // 1. Offload fail if no OffloadConfig.
+        initOffloadConfiguration(false /* offloadConfig */, true /* offloadControl */,
+                0 /* defaultDisabled */);
+        runUsbTethering(upstreamState);
+        callback.expectOffloadStatusChanged(TETHER_HARDWARE_OFFLOAD_FAILED);
+        runStopUSBTethering();
+        callback.expectOffloadStatusChanged(TETHER_HARDWARE_OFFLOAD_STOPPED);
+        reset(mUsbManager);
+        // 2. Offload fail if no OffloadControl.
+        initOffloadConfiguration(true /* offloadConfig */, false /* offloadControl */,
+                0 /* defaultDisabled */);
+        runUsbTethering(upstreamState);
+        callback.expectOffloadStatusChanged(TETHER_HARDWARE_OFFLOAD_FAILED);
+        runStopUSBTethering();
+        callback.expectOffloadStatusChanged(TETHER_HARDWARE_OFFLOAD_STOPPED);
+        reset(mUsbManager);
+        // 3. Offload fail if disabled by settings.
+        initOffloadConfiguration(true /* offloadConfig */, true /* offloadControl */,
+                1 /* defaultDisabled */);
+        runUsbTethering(upstreamState);
+        callback.expectOffloadStatusChanged(TETHER_HARDWARE_OFFLOAD_FAILED);
+        runStopUSBTethering();
+        callback.expectOffloadStatusChanged(TETHER_HARDWARE_OFFLOAD_STOPPED);
+    }
+
+    private void runStopUSBTethering() {
+        mTethering.stopTethering(TETHERING_USB);
+        mLooper.dispatchAll();
+        mTethering.interfaceRemoved(TEST_USB_IFNAME);
+        mLooper.dispatchAll();
+    }
+
+    private void initOffloadConfiguration(final boolean offloadConfig,
+            final boolean offloadControl, final int defaultDisabled) {
+        when(mOffloadHardwareInterface.initOffloadConfig()).thenReturn(offloadConfig);
+        when(mOffloadHardwareInterface.initOffloadControl(any())).thenReturn(offloadControl);
+        when(mOffloadHardwareInterface.getDefaultTetherOffloadDisabled()).thenReturn(
+                defaultDisabled);
+    }
+
+    @Test
+    public void testMultiSimAware() throws Exception {
+        final TetheringConfiguration initailConfig = mTethering.getTetheringConfiguration();
+        assertEquals(INVALID_SUBSCRIPTION_ID, initailConfig.activeDataSubId);
+
+        final int fakeSubId = 1234;
+        mPhoneStateListener.onActiveDataSubscriptionIdChanged(fakeSubId);
+        final TetheringConfiguration newConfig = mTethering.getTetheringConfiguration();
+        assertEquals(fakeSubId, newConfig.activeDataSubId);
+        verify(mNotificationUpdater, times(1)).onActiveDataSubscriptionIdChanged(eq(fakeSubId));
+    }
+
+    @Test
+    public void testNoDuplicatedEthernetRequest() throws Exception {
+        final TetheredInterfaceRequest mockRequest = mock(TetheredInterfaceRequest.class);
+        when(mEm.requestTetheredInterface(any(), any())).thenReturn(mockRequest);
+        mTethering.startTethering(createTetheringRequestParcel(TETHERING_ETHERNET), null);
+        mLooper.dispatchAll();
+        verify(mEm, times(1)).requestTetheredInterface(any(), any());
+        mTethering.startTethering(createTetheringRequestParcel(TETHERING_ETHERNET), null);
+        mLooper.dispatchAll();
+        verifyNoMoreInteractions(mEm);
+        mTethering.stopTethering(TETHERING_ETHERNET);
+        mLooper.dispatchAll();
+        verify(mockRequest, times(1)).release();
+        mTethering.stopTethering(TETHERING_ETHERNET);
+        mLooper.dispatchAll();
+        verifyNoMoreInteractions(mEm);
+    }
+
+    private void workingWifiP2pGroupOwner(
+            boolean emulateInterfaceStatusChanged) throws Exception {
+        if (emulateInterfaceStatusChanged) {
+            mTethering.interfaceStatusChanged(TEST_P2P_IFNAME, true);
+        }
+        sendWifiP2pConnectionChanged(true, true, TEST_P2P_IFNAME);
+        mLooper.dispatchAll();
+
+        verifyInterfaceServingModeStarted(TEST_P2P_IFNAME);
+        verifyTetheringBroadcast(TEST_P2P_IFNAME, EXTRA_AVAILABLE_TETHER);
+        verify(mNetd, times(1)).ipfwdEnableForwarding(TETHERING_NAME);
+        verify(mNetd, times(1)).tetherStartWithConfiguration(any());
+        verifyNoMoreInteractions(mNetd);
+        verifyTetheringBroadcast(TEST_P2P_IFNAME, EXTRA_ACTIVE_LOCAL_ONLY);
+        verify(mUpstreamNetworkMonitor, times(1)).startObserveAllNetworks();
+        // There are 2 IpServer state change events: STATE_AVAILABLE -> STATE_LOCAL_ONLY
+        verify(mNotificationUpdater, times(2)).onDownstreamChanged(DOWNSTREAM_NONE);
+
+        assertEquals(TETHER_ERROR_NO_ERROR, mTethering.getLastTetherError(TEST_P2P_IFNAME));
+
+        // Emulate externally-visible WifiP2pManager effects, when wifi p2p group
+        // is being removed.
+        sendWifiP2pConnectionChanged(false, true, TEST_P2P_IFNAME);
+        mTethering.interfaceRemoved(TEST_P2P_IFNAME);
+        mLooper.dispatchAll();
+
+        verify(mNetd, times(1)).tetherApplyDnsInterfaces();
+        verify(mNetd, times(1)).tetherInterfaceRemove(TEST_P2P_IFNAME);
+        verify(mNetd, times(1)).networkRemoveInterface(INetd.LOCAL_NET_ID, TEST_P2P_IFNAME);
+        // interfaceSetCfg() called once for enabling and twice for disabling IPv4.
+        verify(mNetd, times(3)).interfaceSetCfg(any(InterfaceConfigurationParcel.class));
+        verify(mNetd, times(1)).tetherStop();
+        verify(mNetd, times(1)).ipfwdDisableForwarding(TETHERING_NAME);
+        verify(mUpstreamNetworkMonitor, never()).getCurrentPreferredUpstream();
+        verify(mUpstreamNetworkMonitor, never()).selectPreferredUpstreamType(any());
+        verifyNoMoreInteractions(mNetd);
+        // Asking for the last error after the per-interface state machine
+        // has been reaped yields an unknown interface error.
+        assertEquals(TETHER_ERROR_UNKNOWN_IFACE, mTethering.getLastTetherError(TEST_P2P_IFNAME));
+    }
+
+    private void workingWifiP2pGroupClient(
+            boolean emulateInterfaceStatusChanged) throws Exception {
+        if (emulateInterfaceStatusChanged) {
+            mTethering.interfaceStatusChanged(TEST_P2P_IFNAME, true);
+        }
+        sendWifiP2pConnectionChanged(true, false, TEST_P2P_IFNAME);
+        mLooper.dispatchAll();
+
+        verify(mNetd, never()).interfaceSetCfg(any(InterfaceConfigurationParcel.class));
+        verify(mNetd, never()).tetherInterfaceAdd(TEST_P2P_IFNAME);
+        verify(mNetd, never()).networkAddInterface(INetd.LOCAL_NET_ID, TEST_P2P_IFNAME);
+        verify(mNetd, never()).ipfwdEnableForwarding(TETHERING_NAME);
+        verify(mNetd, never()).tetherStartWithConfiguration(any());
+
+        // Emulate externally-visible WifiP2pManager effects, when wifi p2p group
+        // is being removed.
+        sendWifiP2pConnectionChanged(false, false, TEST_P2P_IFNAME);
+        mTethering.interfaceRemoved(TEST_P2P_IFNAME);
+        mLooper.dispatchAll();
+
+        verify(mNetd, never()).tetherApplyDnsInterfaces();
+        verify(mNetd, never()).tetherInterfaceRemove(TEST_P2P_IFNAME);
+        verify(mNetd, never()).networkRemoveInterface(INetd.LOCAL_NET_ID, TEST_P2P_IFNAME);
+        verify(mNetd, never()).interfaceSetCfg(any(InterfaceConfigurationParcel.class));
+        verify(mNetd, never()).tetherStop();
+        verify(mNetd, never()).ipfwdDisableForwarding(TETHERING_NAME);
+        verifyNoMoreInteractions(mNetd);
+        // Asking for the last error after the per-interface state machine
+        // has been reaped yields an unknown interface error.
+        assertEquals(TETHER_ERROR_UNKNOWN_IFACE, mTethering.getLastTetherError(TEST_P2P_IFNAME));
+    }
+
+    @Test
+    public void workingWifiP2pGroupOwnerWithIfaceChanged() throws Exception {
+        workingWifiP2pGroupOwner(true);
+    }
+
+    @Test
+    public void workingWifiP2pGroupOwnerSansIfaceChanged() throws Exception {
+        workingWifiP2pGroupOwner(false);
+    }
+
+    private void workingWifiP2pGroupOwnerLegacyMode(
+            boolean emulateInterfaceStatusChanged) throws Exception {
+        // change to legacy mode and update tethering information by chaning SIM
+        when(mResources.getStringArray(R.array.config_tether_wifi_p2p_regexs))
+                .thenReturn(new String[]{});
+        final int fakeSubId = 1234;
+        mPhoneStateListener.onActiveDataSubscriptionIdChanged(fakeSubId);
+
+        if (emulateInterfaceStatusChanged) {
+            mTethering.interfaceStatusChanged(TEST_P2P_IFNAME, true);
+        }
+        sendWifiP2pConnectionChanged(true, true, TEST_P2P_IFNAME);
+        mLooper.dispatchAll();
+
+        verify(mNetd, never()).interfaceSetCfg(any(InterfaceConfigurationParcel.class));
+        verify(mNetd, never()).tetherInterfaceAdd(TEST_P2P_IFNAME);
+        verify(mNetd, never()).networkAddInterface(INetd.LOCAL_NET_ID, TEST_P2P_IFNAME);
+        verify(mNetd, never()).ipfwdEnableForwarding(TETHERING_NAME);
+        verify(mNetd, never()).tetherStartWithConfiguration(any());
+        assertEquals(TETHER_ERROR_UNKNOWN_IFACE, mTethering.getLastTetherError(TEST_P2P_IFNAME));
+    }
+    @Test
+    public void workingWifiP2pGroupOwnerLegacyModeWithIfaceChanged() throws Exception {
+        workingWifiP2pGroupOwnerLegacyMode(true);
+    }
+
+    @Test
+    public void workingWifiP2pGroupOwnerLegacyModeSansIfaceChanged() throws Exception {
+        workingWifiP2pGroupOwnerLegacyMode(false);
+    }
+
+    @Test
+    public void workingWifiP2pGroupClientWithIfaceChanged() throws Exception {
+        workingWifiP2pGroupClient(true);
+    }
+
+    @Test
+    public void workingWifiP2pGroupClientSansIfaceChanged() throws Exception {
+        workingWifiP2pGroupClient(false);
+    }
+
+    private void setDataSaverEnabled(boolean enabled) {
+        final Intent intent = new Intent(ACTION_RESTRICT_BACKGROUND_CHANGED);
+        mServiceContext.sendBroadcastAsUser(intent, UserHandle.ALL);
+
+        final int status = enabled ? RESTRICT_BACKGROUND_STATUS_ENABLED
+                : RESTRICT_BACKGROUND_STATUS_DISABLED;
+        when(mCm.getRestrictBackgroundStatus()).thenReturn(status);
+        mLooper.dispatchAll();
+    }
+
+    @Test
+    public void testDataSaverChanged() {
+        // Start Tethering.
+        final UpstreamNetworkState upstreamState = buildMobileIPv4UpstreamState();
+        runUsbTethering(upstreamState);
+        assertContains(Arrays.asList(mTethering.getTetheredIfaces()), TEST_USB_IFNAME);
+        // Data saver is ON.
+        setDataSaverEnabled(true);
+        // Verify that tethering should be disabled.
+        verify(mUsbManager, times(1)).setCurrentFunctions(UsbManager.FUNCTION_NONE);
+        mTethering.interfaceRemoved(TEST_USB_IFNAME);
+        mLooper.dispatchAll();
+        assertEquals(mTethering.getTetheredIfaces(), new String[0]);
+        reset(mUsbManager);
+
+        runUsbTethering(upstreamState);
+        // Verify that user can start tethering again without turning OFF data saver.
+        assertContains(Arrays.asList(mTethering.getTetheredIfaces()), TEST_USB_IFNAME);
+
+        // If data saver is keep ON with change event, tethering should not be OFF this time.
+        setDataSaverEnabled(true);
+        verify(mUsbManager, times(0)).setCurrentFunctions(UsbManager.FUNCTION_NONE);
+        assertContains(Arrays.asList(mTethering.getTetheredIfaces()), TEST_USB_IFNAME);
+
+        // If data saver is turned OFF, it should not change tethering.
+        setDataSaverEnabled(false);
+        verify(mUsbManager, times(0)).setCurrentFunctions(UsbManager.FUNCTION_NONE);
+        assertContains(Arrays.asList(mTethering.getTetheredIfaces()), TEST_USB_IFNAME);
+    }
+
+    private static <T> void assertContains(Collection<T> collection, T element) {
+        assertTrue(element + " not found in " + collection, collection.contains(element));
+    }
+
+    private class ResultListener extends IIntResultListener.Stub {
+        private final int mExpectedResult;
+        private boolean mHasResult = false;
+        ResultListener(final int expectedResult) {
+            mExpectedResult = expectedResult;
+        }
+
+        @Override
+        public void onResult(final int resultCode) {
+            mHasResult = true;
+            if (resultCode != mExpectedResult) {
+                fail("expected result: " + mExpectedResult + " but actual result: " + resultCode);
+            }
+        }
+
+        public void assertHasResult() {
+            if (!mHasResult) fail("No callback result");
+        }
+    }
+
+    @Test
+    public void testMultipleStartTethering() throws Exception {
+        final LinkAddress serverLinkAddr = new LinkAddress("192.168.20.1/24");
+        final LinkAddress clientLinkAddr = new LinkAddress("192.168.20.42/24");
+        final String serverAddr = "192.168.20.1";
+        final ResultListener firstResult = new ResultListener(TETHER_ERROR_NO_ERROR);
+        final ResultListener secondResult = new ResultListener(TETHER_ERROR_NO_ERROR);
+        final ResultListener thirdResult = new ResultListener(TETHER_ERROR_NO_ERROR);
+
+        // Enable USB tethering and check that Tethering starts USB.
+        mTethering.startTethering(createTetheringRequestParcel(TETHERING_USB,
+                  null, null, false), firstResult);
+        mLooper.dispatchAll();
+        firstResult.assertHasResult();
+        verify(mUsbManager, times(1)).setCurrentFunctions(UsbManager.FUNCTION_RNDIS);
+        verifyNoMoreInteractions(mUsbManager);
+
+        // Enable USB tethering again with the same request and expect no change to USB.
+        mTethering.startTethering(createTetheringRequestParcel(TETHERING_USB,
+                  null, null, false), secondResult);
+        mLooper.dispatchAll();
+        secondResult.assertHasResult();
+        verify(mUsbManager, never()).setCurrentFunctions(UsbManager.FUNCTION_NONE);
+        reset(mUsbManager);
+
+        // Enable USB tethering with a different request and expect that USB is stopped and
+        // started.
+        mTethering.startTethering(createTetheringRequestParcel(TETHERING_USB,
+                  serverLinkAddr, clientLinkAddr, false), thirdResult);
+        mLooper.dispatchAll();
+        thirdResult.assertHasResult();
+        verify(mUsbManager, times(1)).setCurrentFunctions(UsbManager.FUNCTION_NONE);
+        verify(mUsbManager, times(1)).setCurrentFunctions(UsbManager.FUNCTION_RNDIS);
+
+        // Expect that when USB comes up, the DHCP server is configured with the requested address.
+        mTethering.interfaceStatusChanged(TEST_USB_IFNAME, true);
+        sendUsbBroadcast(true, true, true, TETHERING_USB);
+        mLooper.dispatchAll();
+        verify(mDhcpServer, timeout(DHCPSERVER_START_TIMEOUT_MS).times(1)).startWithCallbacks(
+                any(), any());
+        verify(mNetd).interfaceSetCfg(argThat(cfg -> serverAddr.equals(cfg.ipv4Addr)));
+    }
+
+    @Test
+    public void testRequestStaticIp() throws Exception {
+        final LinkAddress serverLinkAddr = new LinkAddress("192.168.0.123/24");
+        final LinkAddress clientLinkAddr = new LinkAddress("192.168.0.42/24");
+        final String serverAddr = "192.168.0.123";
+        final int clientAddrParceled = 0xc0a8002a;
+        final ArgumentCaptor<DhcpServingParamsParcel> dhcpParamsCaptor =
+                ArgumentCaptor.forClass(DhcpServingParamsParcel.class);
+        mTethering.startTethering(createTetheringRequestParcel(TETHERING_USB,
+                  serverLinkAddr, clientLinkAddr, false), null);
+        mLooper.dispatchAll();
+        verify(mUsbManager, times(1)).setCurrentFunctions(UsbManager.FUNCTION_RNDIS);
+        mTethering.interfaceStatusChanged(TEST_USB_IFNAME, true);
+        sendUsbBroadcast(true, true, true, TETHERING_USB);
+        mLooper.dispatchAll();
+        verify(mNetd).interfaceSetCfg(argThat(cfg -> serverAddr.equals(cfg.ipv4Addr)));
+        verify(mIpServerDependencies, times(1)).makeDhcpServer(any(), dhcpParamsCaptor.capture(),
+                any());
+        final DhcpServingParamsParcel params = dhcpParamsCaptor.getValue();
+        assertEquals(serverAddr, intToInet4AddressHTH(params.serverAddr).getHostAddress());
+        assertEquals(24, params.serverAddrPrefixLength);
+        assertEquals(clientAddrParceled, params.singleClientAddr);
+    }
+
+    @Test
+    public void testUpstreamNetworkChanged() {
+        final Tethering.TetherMainSM stateMachine = (Tethering.TetherMainSM)
+                mTetheringDependencies.mUpstreamNetworkMonitorSM;
+        final UpstreamNetworkState upstreamState = buildMobileIPv4UpstreamState();
+        initTetheringUpstream(upstreamState);
+        stateMachine.chooseUpstreamType(true);
+
+        verify(mUpstreamNetworkMonitor, times(1)).setCurrentUpstream(eq(upstreamState.network));
+        verify(mNotificationUpdater, times(1)).onUpstreamCapabilitiesChanged(any());
+    }
+
+    @Test
+    public void testUpstreamCapabilitiesChanged() {
+        final Tethering.TetherMainSM stateMachine = (Tethering.TetherMainSM)
+                mTetheringDependencies.mUpstreamNetworkMonitorSM;
+        final UpstreamNetworkState upstreamState = buildMobileIPv4UpstreamState();
+        initTetheringUpstream(upstreamState);
+        stateMachine.chooseUpstreamType(true);
+
+        stateMachine.handleUpstreamNetworkMonitorCallback(EVENT_ON_CAPABILITIES, upstreamState);
+        // Should have two onUpstreamCapabilitiesChanged().
+        // One is called by reportUpstreamChanged(). One is called by EVENT_ON_CAPABILITIES.
+        verify(mNotificationUpdater, times(2)).onUpstreamCapabilitiesChanged(any());
+        reset(mNotificationUpdater);
+
+        // Verify that onUpstreamCapabilitiesChanged won't be called if not current upstream network
+        // capabilities changed.
+        final UpstreamNetworkState upstreamState2 = new UpstreamNetworkState(
+                upstreamState.linkProperties, upstreamState.networkCapabilities, new Network(101));
+        stateMachine.handleUpstreamNetworkMonitorCallback(EVENT_ON_CAPABILITIES, upstreamState2);
+        verify(mNotificationUpdater, never()).onUpstreamCapabilitiesChanged(any());
+    }
+
+    @Test
+    public void testDumpTetheringLog() throws Exception {
+        final FileDescriptor mockFd = mock(FileDescriptor.class);
+        final PrintWriter mockPw = mock(PrintWriter.class);
+        runUsbTethering(null);
+        mLooper.startAutoDispatch();
+        mTethering.dump(mockFd, mockPw, new String[0]);
+        verify(mConfig).dump(any());
+        verify(mEntitleMgr).dump(any());
+        verify(mOffloadCtrl).dump(any());
+        mLooper.stopAutoDispatch();
+    }
+
+    @Test
+    public void testExemptFromEntitlementCheck() throws Exception {
+        setupForRequiredProvisioning();
+        final TetheringRequestParcel wifiNotExemptRequest =
+                createTetheringRequestParcel(TETHERING_WIFI, null, null, false);
+        mTethering.startTethering(wifiNotExemptRequest, null);
+        mLooper.dispatchAll();
+        verify(mEntitleMgr).startProvisioningIfNeeded(TETHERING_WIFI, false);
+        verify(mEntitleMgr, never()).setExemptedDownstreamType(TETHERING_WIFI);
+        assertFalse(mEntitleMgr.isCellularUpstreamPermitted());
+        mTethering.stopTethering(TETHERING_WIFI);
+        mLooper.dispatchAll();
+        verify(mEntitleMgr).stopProvisioningIfNeeded(TETHERING_WIFI);
+        reset(mEntitleMgr);
+
+        setupForRequiredProvisioning();
+        final TetheringRequestParcel wifiExemptRequest =
+                createTetheringRequestParcel(TETHERING_WIFI, null, null, true);
+        mTethering.startTethering(wifiExemptRequest, null);
+        mLooper.dispatchAll();
+        verify(mEntitleMgr, never()).startProvisioningIfNeeded(TETHERING_WIFI, false);
+        verify(mEntitleMgr).setExemptedDownstreamType(TETHERING_WIFI);
+        assertTrue(mEntitleMgr.isCellularUpstreamPermitted());
+        mTethering.stopTethering(TETHERING_WIFI);
+        mLooper.dispatchAll();
+        verify(mEntitleMgr).stopProvisioningIfNeeded(TETHERING_WIFI);
+        reset(mEntitleMgr);
+
+        // If one app enables tethering without provisioning check first, then another app enables
+        // tethering of the same type but does not disable the provisioning check.
+        setupForRequiredProvisioning();
+        mTethering.startTethering(wifiExemptRequest, null);
+        mLooper.dispatchAll();
+        verify(mEntitleMgr, never()).startProvisioningIfNeeded(TETHERING_WIFI, false);
+        verify(mEntitleMgr).setExemptedDownstreamType(TETHERING_WIFI);
+        assertTrue(mEntitleMgr.isCellularUpstreamPermitted());
+        reset(mEntitleMgr);
+        setupForRequiredProvisioning();
+        mTethering.startTethering(wifiNotExemptRequest, null);
+        mLooper.dispatchAll();
+        verify(mEntitleMgr).startProvisioningIfNeeded(TETHERING_WIFI, false);
+        verify(mEntitleMgr, never()).setExemptedDownstreamType(TETHERING_WIFI);
+        assertFalse(mEntitleMgr.isCellularUpstreamPermitted());
+        mTethering.stopTethering(TETHERING_WIFI);
+        mLooper.dispatchAll();
+        verify(mEntitleMgr).stopProvisioningIfNeeded(TETHERING_WIFI);
+        reset(mEntitleMgr);
+    }
+
+    private void setupForRequiredProvisioning() {
+        // Produce some acceptable looking provision app setting if requested.
+        when(mResources.getStringArray(R.array.config_mobile_hotspot_provision_app))
+                .thenReturn(PROVISIONING_APP_NAME);
+        when(mResources.getString(R.string.config_mobile_hotspot_provision_app_no_ui))
+                .thenReturn(PROVISIONING_NO_UI_APP_NAME);
+        // Act like the CarrierConfigManager is present and ready unless told otherwise.
+        when(mContext.getSystemService(Context.CARRIER_CONFIG_SERVICE))
+                .thenReturn(mCarrierConfigManager);
+        when(mCarrierConfigManager.getConfigForSubId(anyInt())).thenReturn(mCarrierConfig);
+        mCarrierConfig.putBoolean(CarrierConfigManager.KEY_REQUIRE_ENTITLEMENT_CHECKS_BOOL, true);
+        mCarrierConfig.putBoolean(CarrierConfigManager.KEY_CARRIER_CONFIG_APPLIED_BOOL, true);
+        sendConfigurationChanged();
+    }
+
+    private static UpstreamNetworkState buildV4UpstreamState(final LinkAddress address,
+            final Network network, final String iface, final int transportType) {
+        final LinkProperties prop = new LinkProperties();
+        prop.setInterfaceName(iface);
+
+        prop.addLinkAddress(address);
+
+        final NetworkCapabilities capabilities = new NetworkCapabilities()
+                .addTransportType(transportType);
+        return new UpstreamNetworkState(prop, capabilities, network);
+    }
+
+    private void updateV4Upstream(final LinkAddress ipv4Address, final Network network,
+            final String iface, final int transportType) {
+        final UpstreamNetworkState upstream = buildV4UpstreamState(ipv4Address, network, iface,
+                transportType);
+        mTetheringDependencies.mUpstreamNetworkMonitorSM.sendMessage(
+                Tethering.TetherMainSM.EVENT_UPSTREAM_CALLBACK,
+                UpstreamNetworkMonitor.EVENT_ON_LINKPROPERTIES,
+                0,
+                upstream);
+        mLooper.dispatchAll();
+    }
+
+    @Test
+    public void testHandleIpConflict() throws Exception {
+        final Network wifiNetwork = new Network(200);
+        final Network[] allNetworks = { wifiNetwork };
+        when(mCm.getAllNetworks()).thenReturn(allNetworks);
+        runUsbTethering(null);
+        final ArgumentCaptor<InterfaceConfigurationParcel> ifaceConfigCaptor =
+                ArgumentCaptor.forClass(InterfaceConfigurationParcel.class);
+        verify(mNetd).interfaceSetCfg(ifaceConfigCaptor.capture());
+        final String ipv4Address = ifaceConfigCaptor.getValue().ipv4Addr;
+        verify(mDhcpServer, timeout(DHCPSERVER_START_TIMEOUT_MS).times(1)).startWithCallbacks(
+                any(), any());
+        reset(mNetd, mUsbManager);
+
+        // Cause a prefix conflict by assigning a /30 out of the downstream's /24 to the upstream.
+        updateV4Upstream(new LinkAddress(InetAddresses.parseNumericAddress(ipv4Address), 30),
+                wifiNetwork, TEST_WIFI_IFNAME, TRANSPORT_WIFI);
+        // verify turn off usb tethering
+        verify(mUsbManager).setCurrentFunctions(UsbManager.FUNCTION_NONE);
+        mTethering.interfaceRemoved(TEST_USB_IFNAME);
+        mLooper.dispatchAll();
+        // verify restart usb tethering
+        verify(mUsbManager).setCurrentFunctions(UsbManager.FUNCTION_RNDIS);
+    }
+
+    @Test
+    public void testNoAddressAvailable() throws Exception {
+        final Network wifiNetwork = new Network(200);
+        final Network btNetwork = new Network(201);
+        final Network mobileNetwork = new Network(202);
+        final Network[] allNetworks = { wifiNetwork, btNetwork, mobileNetwork };
+        when(mCm.getAllNetworks()).thenReturn(allNetworks);
+        runUsbTethering(null);
+        verify(mDhcpServer, timeout(DHCPSERVER_START_TIMEOUT_MS).times(1)).startWithCallbacks(
+                any(), any());
+        reset(mUsbManager);
+        final TetheredInterfaceRequest mockRequest = mock(TetheredInterfaceRequest.class);
+        when(mEm.requestTetheredInterface(any(), any())).thenReturn(mockRequest);
+        final ArgumentCaptor<TetheredInterfaceCallback> callbackCaptor =
+                ArgumentCaptor.forClass(TetheredInterfaceCallback.class);
+        mTethering.startTethering(createTetheringRequestParcel(TETHERING_ETHERNET), null);
+        mLooper.dispatchAll();
+        verify(mEm).requestTetheredInterface(any(), callbackCaptor.capture());
+        TetheredInterfaceCallback ethCallback = callbackCaptor.getValue();
+        ethCallback.onAvailable(TEST_ETH_IFNAME);
+        mLooper.dispatchAll();
+        reset(mUsbManager, mEm);
+
+        updateV4Upstream(new LinkAddress("192.168.0.100/16"), wifiNetwork, TEST_WIFI_IFNAME,
+                TRANSPORT_WIFI);
+        updateV4Upstream(new LinkAddress("172.16.0.0/12"), btNetwork, TEST_BT_IFNAME,
+                TRANSPORT_BLUETOOTH);
+        updateV4Upstream(new LinkAddress("10.0.0.0/8"), mobileNetwork, TEST_MOBILE_IFNAME,
+                TRANSPORT_CELLULAR);
+
+        mLooper.dispatchAll();
+        // verify turn off usb tethering
+        verify(mUsbManager).setCurrentFunctions(UsbManager.FUNCTION_NONE);
+        // verify turn off ethernet tethering
+        verify(mockRequest).release();
+        mTethering.interfaceRemoved(TEST_USB_IFNAME);
+        ethCallback.onUnavailable();
+        mLooper.dispatchAll();
+        // verify restart usb tethering
+        verify(mUsbManager).setCurrentFunctions(UsbManager.FUNCTION_RNDIS);
+        // verify restart ethernet tethering
+        verify(mEm).requestTetheredInterface(any(), callbackCaptor.capture());
+        ethCallback = callbackCaptor.getValue();
+        ethCallback.onAvailable(TEST_ETH_IFNAME);
+
+        reset(mUsbManager, mEm);
+        when(mNetd.interfaceGetList())
+                .thenReturn(new String[] {
+                        TEST_MOBILE_IFNAME, TEST_WLAN_IFNAME, TEST_USB_IFNAME, TEST_P2P_IFNAME,
+                        TEST_NCM_IFNAME, TEST_ETH_IFNAME});
+
+        mTethering.interfaceStatusChanged(TEST_USB_IFNAME, true);
+        sendUsbBroadcast(true, true, true, TETHERING_USB);
+        mLooper.dispatchAll();
+        assertContains(Arrays.asList(mTethering.getTetherableIfaces()), TEST_USB_IFNAME);
+        assertContains(Arrays.asList(mTethering.getTetherableIfaces()), TEST_ETH_IFNAME);
+        assertEquals(TETHER_ERROR_IFACE_CFG_ERROR, mTethering.getLastTetherError(TEST_USB_IFNAME));
+        assertEquals(TETHER_ERROR_IFACE_CFG_ERROR, mTethering.getLastTetherError(TEST_ETH_IFNAME));
+    }
+
+    @Test
+    public void testProvisioningNeededButUnavailable() throws Exception {
+        assertTrue(mTethering.isTetheringSupported());
+        verify(mPackageManager, never()).getPackageInfo(PROVISIONING_APP_NAME[0], GET_ACTIVITIES);
+
+        setupForRequiredProvisioning();
+        assertTrue(mTethering.isTetheringSupported());
+        verify(mPackageManager).getPackageInfo(PROVISIONING_APP_NAME[0], GET_ACTIVITIES);
+        reset(mPackageManager);
+
+        doThrow(PackageManager.NameNotFoundException.class).when(mPackageManager).getPackageInfo(
+                PROVISIONING_APP_NAME[0], GET_ACTIVITIES);
+        setupForRequiredProvisioning();
+        assertFalse(mTethering.isTetheringSupported());
+        verify(mPackageManager).getPackageInfo(PROVISIONING_APP_NAME[0], GET_ACTIVITIES);
+    }
+
+    // TODO: Test that a request for hotspot mode doesn't interfere with an
+    // already operating tethering mode interface.
+}
diff --git a/Tethering/tests/unit/src/com/android/networkstack/tethering/UpstreamNetworkMonitorTest.java b/Tethering/tests/unit/src/com/android/networkstack/tethering/UpstreamNetworkMonitorTest.java
new file mode 100644
index 0000000..232588c
--- /dev/null
+++ b/Tethering/tests/unit/src/com/android/networkstack/tethering/UpstreamNetworkMonitorTest.java
@@ -0,0 +1,800 @@
+/*
+ * Copyright (C) 2017 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.android.networkstack.tethering;
+
+import static android.net.ConnectivityManager.TYPE_MOBILE_DUN;
+import static android.net.ConnectivityManager.TYPE_MOBILE_HIPRI;
+import static android.net.ConnectivityManager.TYPE_WIFI;
+import static android.net.NetworkCapabilities.NET_CAPABILITY_DUN;
+import static android.net.NetworkCapabilities.NET_CAPABILITY_INTERNET;
+import static android.net.NetworkCapabilities.TRANSPORT_CELLULAR;
+import static android.net.NetworkCapabilities.TRANSPORT_WIFI;
+
+import static com.android.networkstack.tethering.UpstreamNetworkMonitor.TYPE_NONE;
+
+import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertFalse;
+import static org.junit.Assert.assertTrue;
+import static org.junit.Assert.fail;
+import static org.mockito.Mockito.any;
+import static org.mockito.Mockito.anyInt;
+import static org.mockito.Mockito.anyString;
+import static org.mockito.Mockito.eq;
+import static org.mockito.Mockito.reset;
+import static org.mockito.Mockito.spy;
+import static org.mockito.Mockito.times;
+import static org.mockito.Mockito.verify;
+import static org.mockito.Mockito.verifyNoMoreInteractions;
+import static org.mockito.Mockito.when;
+
+import android.content.Context;
+import android.net.ConnectivityManager;
+import android.net.ConnectivityManager.NetworkCallback;
+import android.net.IConnectivityManager;
+import android.net.IpPrefix;
+import android.net.LinkAddress;
+import android.net.LinkProperties;
+import android.net.Network;
+import android.net.NetworkCapabilities;
+import android.net.NetworkRequest;
+import android.net.util.SharedLog;
+import android.os.Handler;
+import android.os.Message;
+
+import androidx.test.filters.SmallTest;
+import androidx.test.runner.AndroidJUnit4;
+
+import com.android.internal.util.State;
+import com.android.internal.util.StateMachine;
+
+import org.junit.After;
+import org.junit.Before;
+import org.junit.Test;
+import org.junit.runner.RunWith;
+import org.mockito.Mock;
+import org.mockito.MockitoAnnotations;
+
+import java.util.ArrayList;
+import java.util.Collection;
+import java.util.Collections;
+import java.util.HashMap;
+import java.util.HashSet;
+import java.util.Map;
+import java.util.Objects;
+import java.util.Set;
+
+@RunWith(AndroidJUnit4.class)
+@SmallTest
+public class UpstreamNetworkMonitorTest {
+    private static final int EVENT_UNM_UPDATE = 1;
+
+    private static final boolean INCLUDES = true;
+    private static final boolean EXCLUDES = false;
+
+    // Actual contents of the request don't matter for this test. The lack of
+    // any specific TRANSPORT_* is sufficient to identify this request.
+    private static final NetworkRequest sDefaultRequest = new NetworkRequest.Builder().build();
+
+    @Mock private Context mContext;
+    @Mock private EntitlementManager mEntitleMgr;
+    @Mock private IConnectivityManager mCS;
+    @Mock private SharedLog mLog;
+
+    private TestStateMachine mSM;
+    private TestConnectivityManager mCM;
+    private UpstreamNetworkMonitor mUNM;
+
+    @Before public void setUp() throws Exception {
+        MockitoAnnotations.initMocks(this);
+        reset(mContext);
+        reset(mCS);
+        reset(mLog);
+        when(mLog.forSubComponent(anyString())).thenReturn(mLog);
+        when(mEntitleMgr.isCellularUpstreamPermitted()).thenReturn(true);
+
+        mCM = spy(new TestConnectivityManager(mContext, mCS));
+        mSM = new TestStateMachine();
+        mUNM = new UpstreamNetworkMonitor(
+                (ConnectivityManager) mCM, mSM, mLog, EVENT_UNM_UPDATE);
+    }
+
+    @After public void tearDown() throws Exception {
+        if (mSM != null) {
+            mSM.quit();
+            mSM = null;
+        }
+    }
+
+    @Test
+    public void testStopWithoutStartIsNonFatal() {
+        mUNM.stop();
+        mUNM.stop();
+        mUNM.stop();
+    }
+
+    @Test
+    public void testDoesNothingBeforeTrackDefaultAndStarted() throws Exception {
+        assertTrue(mCM.hasNoCallbacks());
+        assertFalse(mUNM.mobileNetworkRequested());
+
+        mUNM.updateMobileRequiresDun(true);
+        assertTrue(mCM.hasNoCallbacks());
+        mUNM.updateMobileRequiresDun(false);
+        assertTrue(mCM.hasNoCallbacks());
+    }
+
+    @Test
+    public void testDefaultNetworkIsTracked() throws Exception {
+        assertTrue(mCM.hasNoCallbacks());
+        mUNM.startTrackDefaultNetwork(sDefaultRequest, mEntitleMgr);
+
+        mUNM.startObserveAllNetworks();
+        assertEquals(1, mCM.trackingDefault.size());
+
+        mUNM.stop();
+        assertTrue(mCM.onlyHasDefaultCallbacks());
+    }
+
+    @Test
+    public void testListensForAllNetworks() throws Exception {
+        assertTrue(mCM.listening.isEmpty());
+
+        mUNM.startTrackDefaultNetwork(sDefaultRequest, mEntitleMgr);
+        mUNM.startObserveAllNetworks();
+        assertFalse(mCM.listening.isEmpty());
+        assertTrue(mCM.isListeningForAll());
+
+        mUNM.stop();
+        assertTrue(mCM.onlyHasDefaultCallbacks());
+    }
+
+    @Test
+    public void testCallbacksRegistered() {
+        mUNM.startTrackDefaultNetwork(sDefaultRequest, mEntitleMgr);
+        verify(mCM, times(1)).requestNetwork(
+                eq(sDefaultRequest), any(NetworkCallback.class), any(Handler.class));
+        mUNM.startObserveAllNetworks();
+        verify(mCM, times(1)).registerNetworkCallback(
+                any(NetworkRequest.class), any(NetworkCallback.class), any(Handler.class));
+
+        mUNM.stop();
+        verify(mCM, times(1)).unregisterNetworkCallback(any(NetworkCallback.class));
+    }
+
+    @Test
+    public void testRequestsMobileNetwork() throws Exception {
+        assertFalse(mUNM.mobileNetworkRequested());
+        assertEquals(0, mCM.requested.size());
+
+        mUNM.startObserveAllNetworks();
+        assertFalse(mUNM.mobileNetworkRequested());
+        assertEquals(0, mCM.requested.size());
+
+        mUNM.updateMobileRequiresDun(false);
+        assertFalse(mUNM.mobileNetworkRequested());
+        assertEquals(0, mCM.requested.size());
+
+        mUNM.registerMobileNetworkRequest();
+        assertTrue(mUNM.mobileNetworkRequested());
+        assertUpstreamTypeRequested(TYPE_MOBILE_HIPRI);
+        assertFalse(isDunRequested());
+
+        mUNM.stop();
+        assertFalse(mUNM.mobileNetworkRequested());
+        assertTrue(mCM.hasNoCallbacks());
+    }
+
+    @Test
+    public void testDuplicateMobileRequestsIgnored() throws Exception {
+        assertFalse(mUNM.mobileNetworkRequested());
+        assertEquals(0, mCM.requested.size());
+
+        mUNM.startObserveAllNetworks();
+        verify(mCM, times(1)).registerNetworkCallback(
+                any(NetworkRequest.class), any(NetworkCallback.class), any(Handler.class));
+        assertFalse(mUNM.mobileNetworkRequested());
+        assertEquals(0, mCM.requested.size());
+
+        mUNM.updateMobileRequiresDun(true);
+        mUNM.registerMobileNetworkRequest();
+        verify(mCM, times(1)).requestNetwork(
+                any(NetworkRequest.class), anyInt(), anyInt(), any(Handler.class),
+                any(NetworkCallback.class));
+
+        assertTrue(mUNM.mobileNetworkRequested());
+        assertUpstreamTypeRequested(TYPE_MOBILE_DUN);
+        assertTrue(isDunRequested());
+
+        // Try a few things that must not result in any state change.
+        mUNM.registerMobileNetworkRequest();
+        mUNM.updateMobileRequiresDun(true);
+        mUNM.registerMobileNetworkRequest();
+
+        assertTrue(mUNM.mobileNetworkRequested());
+        assertUpstreamTypeRequested(TYPE_MOBILE_DUN);
+        assertTrue(isDunRequested());
+
+        mUNM.stop();
+        verify(mCM, times(2)).unregisterNetworkCallback(any(NetworkCallback.class));
+
+        verifyNoMoreInteractions(mCM);
+    }
+
+    @Test
+    public void testRequestsDunNetwork() throws Exception {
+        assertFalse(mUNM.mobileNetworkRequested());
+        assertEquals(0, mCM.requested.size());
+
+        mUNM.startObserveAllNetworks();
+        assertFalse(mUNM.mobileNetworkRequested());
+        assertEquals(0, mCM.requested.size());
+
+        mUNM.updateMobileRequiresDun(true);
+        assertFalse(mUNM.mobileNetworkRequested());
+        assertEquals(0, mCM.requested.size());
+
+        mUNM.registerMobileNetworkRequest();
+        assertTrue(mUNM.mobileNetworkRequested());
+        assertUpstreamTypeRequested(TYPE_MOBILE_DUN);
+        assertTrue(isDunRequested());
+
+        mUNM.stop();
+        assertFalse(mUNM.mobileNetworkRequested());
+        assertTrue(mCM.hasNoCallbacks());
+    }
+
+    @Test
+    public void testUpdateMobileRequiresDun() throws Exception {
+        mUNM.startObserveAllNetworks();
+
+        // Test going from no-DUN to DUN correctly re-registers callbacks.
+        mUNM.updateMobileRequiresDun(false);
+        mUNM.registerMobileNetworkRequest();
+        assertTrue(mUNM.mobileNetworkRequested());
+        assertUpstreamTypeRequested(TYPE_MOBILE_HIPRI);
+        assertFalse(isDunRequested());
+        mUNM.updateMobileRequiresDun(true);
+        assertTrue(mUNM.mobileNetworkRequested());
+        assertUpstreamTypeRequested(TYPE_MOBILE_DUN);
+        assertTrue(isDunRequested());
+
+        // Test going from DUN to no-DUN correctly re-registers callbacks.
+        mUNM.updateMobileRequiresDun(false);
+        assertTrue(mUNM.mobileNetworkRequested());
+        assertUpstreamTypeRequested(TYPE_MOBILE_HIPRI);
+        assertFalse(isDunRequested());
+
+        mUNM.stop();
+        assertFalse(mUNM.mobileNetworkRequested());
+    }
+
+    @Test
+    public void testSelectPreferredUpstreamType() throws Exception {
+        final Collection<Integer> preferredTypes = new ArrayList<>();
+        preferredTypes.add(TYPE_WIFI);
+
+        mUNM.startTrackDefaultNetwork(sDefaultRequest, mEntitleMgr);
+        mUNM.startObserveAllNetworks();
+        // There are no networks, so there is nothing to select.
+        assertSatisfiesLegacyType(TYPE_NONE, mUNM.selectPreferredUpstreamType(preferredTypes));
+
+        final TestNetworkAgent wifiAgent = new TestNetworkAgent(mCM, TRANSPORT_WIFI);
+        wifiAgent.fakeConnect();
+        // WiFi is up, we should prefer it.
+        assertSatisfiesLegacyType(TYPE_WIFI, mUNM.selectPreferredUpstreamType(preferredTypes));
+        wifiAgent.fakeDisconnect();
+        // There are no networks, so there is nothing to select.
+        assertSatisfiesLegacyType(TYPE_NONE, mUNM.selectPreferredUpstreamType(preferredTypes));
+
+        final TestNetworkAgent cellAgent = new TestNetworkAgent(mCM, TRANSPORT_CELLULAR);
+        cellAgent.fakeConnect();
+        assertSatisfiesLegacyType(TYPE_NONE, mUNM.selectPreferredUpstreamType(preferredTypes));
+
+        preferredTypes.add(TYPE_MOBILE_DUN);
+        // This is coupled with preferred types in TetheringConfiguration.
+        mUNM.updateMobileRequiresDun(true);
+        // DUN is available, but only use regular cell: no upstream selected.
+        assertSatisfiesLegacyType(TYPE_NONE, mUNM.selectPreferredUpstreamType(preferredTypes));
+        preferredTypes.remove(TYPE_MOBILE_DUN);
+        // No WiFi, but our preferred flavour of cell is up.
+        preferredTypes.add(TYPE_MOBILE_HIPRI);
+        // This is coupled with preferred types in TetheringConfiguration.
+        mUNM.updateMobileRequiresDun(false);
+        assertSatisfiesLegacyType(TYPE_MOBILE_HIPRI,
+                mUNM.selectPreferredUpstreamType(preferredTypes));
+        // Check to see we filed an explicit request.
+        assertEquals(1, mCM.requested.size());
+        NetworkRequest netReq = (NetworkRequest) mCM.requested.values().toArray()[0];
+        assertTrue(netReq.networkCapabilities.hasTransport(TRANSPORT_CELLULAR));
+        assertFalse(netReq.networkCapabilities.hasCapability(NET_CAPABILITY_DUN));
+        // mobile is not permitted, we should not use HIPRI.
+        when(mEntitleMgr.isCellularUpstreamPermitted()).thenReturn(false);
+        assertSatisfiesLegacyType(TYPE_NONE, mUNM.selectPreferredUpstreamType(preferredTypes));
+        assertEquals(0, mCM.requested.size());
+        // mobile change back to permitted, HIRPI should come back
+        when(mEntitleMgr.isCellularUpstreamPermitted()).thenReturn(true);
+        assertSatisfiesLegacyType(TYPE_MOBILE_HIPRI,
+                mUNM.selectPreferredUpstreamType(preferredTypes));
+
+        wifiAgent.fakeConnect();
+        // WiFi is up, and we should prefer it over cell.
+        assertSatisfiesLegacyType(TYPE_WIFI, mUNM.selectPreferredUpstreamType(preferredTypes));
+        assertEquals(0, mCM.requested.size());
+
+        preferredTypes.remove(TYPE_MOBILE_HIPRI);
+        preferredTypes.add(TYPE_MOBILE_DUN);
+        // This is coupled with preferred types in TetheringConfiguration.
+        mUNM.updateMobileRequiresDun(true);
+        assertSatisfiesLegacyType(TYPE_WIFI, mUNM.selectPreferredUpstreamType(preferredTypes));
+
+        final TestNetworkAgent dunAgent = new TestNetworkAgent(mCM, TRANSPORT_CELLULAR);
+        dunAgent.networkCapabilities.addCapability(NET_CAPABILITY_DUN);
+        dunAgent.fakeConnect();
+
+        // WiFi is still preferred.
+        assertSatisfiesLegacyType(TYPE_WIFI, mUNM.selectPreferredUpstreamType(preferredTypes));
+
+        // WiFi goes down, cell and DUN are still up but only DUN is preferred.
+        wifiAgent.fakeDisconnect();
+        assertSatisfiesLegacyType(TYPE_MOBILE_DUN,
+                mUNM.selectPreferredUpstreamType(preferredTypes));
+        // Check to see we filed an explicit request.
+        assertEquals(1, mCM.requested.size());
+        netReq = (NetworkRequest) mCM.requested.values().toArray()[0];
+        assertTrue(netReq.networkCapabilities.hasTransport(TRANSPORT_CELLULAR));
+        assertTrue(netReq.networkCapabilities.hasCapability(NET_CAPABILITY_DUN));
+        // mobile is not permitted, we should not use DUN.
+        when(mEntitleMgr.isCellularUpstreamPermitted()).thenReturn(false);
+        assertSatisfiesLegacyType(TYPE_NONE, mUNM.selectPreferredUpstreamType(preferredTypes));
+        assertEquals(0, mCM.requested.size());
+        // mobile change back to permitted, DUN should come back
+        when(mEntitleMgr.isCellularUpstreamPermitted()).thenReturn(true);
+        assertSatisfiesLegacyType(TYPE_MOBILE_DUN,
+                mUNM.selectPreferredUpstreamType(preferredTypes));
+    }
+
+    @Test
+    public void testGetCurrentPreferredUpstream() throws Exception {
+        mUNM.startTrackDefaultNetwork(sDefaultRequest, mEntitleMgr);
+        mUNM.startObserveAllNetworks();
+        mUNM.updateMobileRequiresDun(false);
+
+        // [0] Mobile connects, DUN not required -> mobile selected.
+        final TestNetworkAgent cellAgent = new TestNetworkAgent(mCM, TRANSPORT_CELLULAR);
+        cellAgent.fakeConnect();
+        mCM.makeDefaultNetwork(cellAgent);
+        assertEquals(cellAgent.networkId, mUNM.getCurrentPreferredUpstream().network);
+
+        // [1] Mobile connects but not permitted -> null selected
+        when(mEntitleMgr.isCellularUpstreamPermitted()).thenReturn(false);
+        assertEquals(null, mUNM.getCurrentPreferredUpstream());
+        when(mEntitleMgr.isCellularUpstreamPermitted()).thenReturn(true);
+
+        // [2] WiFi connects but not validated/promoted to default -> mobile selected.
+        final TestNetworkAgent wifiAgent = new TestNetworkAgent(mCM, TRANSPORT_WIFI);
+        wifiAgent.fakeConnect();
+        assertEquals(cellAgent.networkId, mUNM.getCurrentPreferredUpstream().network);
+
+        // [3] WiFi validates and is promoted to the default network -> WiFi selected.
+        mCM.makeDefaultNetwork(wifiAgent);
+        assertEquals(wifiAgent.networkId, mUNM.getCurrentPreferredUpstream().network);
+
+        // [4] DUN required, no other changes -> WiFi still selected
+        mUNM.updateMobileRequiresDun(true);
+        assertEquals(wifiAgent.networkId, mUNM.getCurrentPreferredUpstream().network);
+
+        // [5] WiFi no longer validated, mobile becomes default, DUN required -> null selected.
+        mCM.makeDefaultNetwork(cellAgent);
+        assertEquals(null, mUNM.getCurrentPreferredUpstream());
+        // TODO: make sure that a DUN request has been filed. This is currently
+        // triggered by code over in Tethering, but once that has been moved
+        // into UNM we should test for this here.
+
+        // [6] DUN network arrives -> DUN selected
+        final TestNetworkAgent dunAgent = new TestNetworkAgent(mCM, TRANSPORT_CELLULAR);
+        dunAgent.networkCapabilities.addCapability(NET_CAPABILITY_DUN);
+        dunAgent.networkCapabilities.removeCapability(NET_CAPABILITY_INTERNET);
+        dunAgent.fakeConnect();
+        assertEquals(dunAgent.networkId, mUNM.getCurrentPreferredUpstream().network);
+
+        // [7] Mobile is not permitted -> null selected
+        when(mEntitleMgr.isCellularUpstreamPermitted()).thenReturn(false);
+        assertEquals(null, mUNM.getCurrentPreferredUpstream());
+    }
+
+    @Test
+    public void testLocalPrefixes() throws Exception {
+        mUNM.startTrackDefaultNetwork(sDefaultRequest, mEntitleMgr);
+        mUNM.startObserveAllNetworks();
+
+        // [0] Test minimum set of local prefixes.
+        Set<IpPrefix> local = mUNM.getLocalPrefixes();
+        assertTrue(local.isEmpty());
+
+        final Set<String> alreadySeen = new HashSet<>();
+
+        // [1] Pretend Wi-Fi connects.
+        final TestNetworkAgent wifiAgent = new TestNetworkAgent(mCM, TRANSPORT_WIFI);
+        final LinkProperties wifiLp = wifiAgent.linkProperties;
+        wifiLp.setInterfaceName("wlan0");
+        final String[] wifi_addrs = {
+                "fe80::827a:bfff:fe6f:374d", "100.112.103.18",
+                "2001:db8:4:fd00:827a:bfff:fe6f:374d",
+                "2001:db8:4:fd00:6dea:325a:fdae:4ef4",
+                "fd6a:a640:60bf:e985::123",  // ULA address for good measure.
+        };
+        for (String addrStr : wifi_addrs) {
+            final String cidr = addrStr.contains(":") ? "/64" : "/20";
+            wifiLp.addLinkAddress(new LinkAddress(addrStr + cidr));
+        }
+        wifiAgent.fakeConnect();
+        wifiAgent.sendLinkProperties();
+
+        local = mUNM.getLocalPrefixes();
+        assertPrefixSet(local, INCLUDES, alreadySeen);
+        final String[] wifiLinkPrefixes = {
+                // Link-local prefixes are excluded and dealt with elsewhere.
+                "100.112.96.0/20", "2001:db8:4:fd00::/64", "fd6a:a640:60bf:e985::/64",
+        };
+        assertPrefixSet(local, INCLUDES, wifiLinkPrefixes);
+        Collections.addAll(alreadySeen, wifiLinkPrefixes);
+        assertEquals(alreadySeen.size(), local.size());
+
+        // [2] Pretend mobile connects.
+        final TestNetworkAgent cellAgent = new TestNetworkAgent(mCM, TRANSPORT_CELLULAR);
+        final LinkProperties cellLp = cellAgent.linkProperties;
+        cellLp.setInterfaceName("rmnet_data0");
+        final String[] cell_addrs = {
+                "10.102.211.48", "2001:db8:0:1:b50e:70d9:10c9:433d",
+        };
+        for (String addrStr : cell_addrs) {
+            final String cidr = addrStr.contains(":") ? "/64" : "/27";
+            cellLp.addLinkAddress(new LinkAddress(addrStr + cidr));
+        }
+        cellAgent.fakeConnect();
+        cellAgent.sendLinkProperties();
+
+        local = mUNM.getLocalPrefixes();
+        assertPrefixSet(local, INCLUDES, alreadySeen);
+        final String[] cellLinkPrefixes = { "10.102.211.32/27", "2001:db8:0:1::/64" };
+        assertPrefixSet(local, INCLUDES, cellLinkPrefixes);
+        Collections.addAll(alreadySeen, cellLinkPrefixes);
+        assertEquals(alreadySeen.size(), local.size());
+
+        // [3] Pretend DUN connects.
+        final TestNetworkAgent dunAgent = new TestNetworkAgent(mCM, TRANSPORT_CELLULAR);
+        dunAgent.networkCapabilities.addCapability(NET_CAPABILITY_DUN);
+        dunAgent.networkCapabilities.removeCapability(NET_CAPABILITY_INTERNET);
+        final LinkProperties dunLp = dunAgent.linkProperties;
+        dunLp.setInterfaceName("rmnet_data1");
+        final String[] dun_addrs = {
+                "192.0.2.48", "2001:db8:1:2:b50e:70d9:10c9:433d",
+        };
+        for (String addrStr : dun_addrs) {
+            final String cidr = addrStr.contains(":") ? "/64" : "/27";
+            dunLp.addLinkAddress(new LinkAddress(addrStr + cidr));
+        }
+        dunAgent.fakeConnect();
+        dunAgent.sendLinkProperties();
+
+        local = mUNM.getLocalPrefixes();
+        assertPrefixSet(local, INCLUDES, alreadySeen);
+        final String[] dunLinkPrefixes = { "192.0.2.32/27", "2001:db8:1:2::/64" };
+        assertPrefixSet(local, INCLUDES, dunLinkPrefixes);
+        Collections.addAll(alreadySeen, dunLinkPrefixes);
+        assertEquals(alreadySeen.size(), local.size());
+
+        // [4] Pretend Wi-Fi disconnected.  It's addresses/prefixes should no
+        // longer be included (should be properly removed).
+        wifiAgent.fakeDisconnect();
+        local = mUNM.getLocalPrefixes();
+        assertPrefixSet(local, EXCLUDES, wifiLinkPrefixes);
+        assertPrefixSet(local, INCLUDES, cellLinkPrefixes);
+        assertPrefixSet(local, INCLUDES, dunLinkPrefixes);
+
+        // [5] Pretend mobile disconnected.
+        cellAgent.fakeDisconnect();
+        local = mUNM.getLocalPrefixes();
+        assertPrefixSet(local, EXCLUDES, wifiLinkPrefixes);
+        assertPrefixSet(local, EXCLUDES, cellLinkPrefixes);
+        assertPrefixSet(local, INCLUDES, dunLinkPrefixes);
+
+        // [6] Pretend DUN disconnected.
+        dunAgent.fakeDisconnect();
+        local = mUNM.getLocalPrefixes();
+        assertTrue(local.isEmpty());
+    }
+
+    @Test
+    public void testSelectMobileWhenMobileIsNotDefault() {
+        final Collection<Integer> preferredTypes = new ArrayList<>();
+        // Mobile has higher pirority than wifi.
+        preferredTypes.add(TYPE_MOBILE_HIPRI);
+        preferredTypes.add(TYPE_WIFI);
+        mUNM.startTrackDefaultNetwork(sDefaultRequest, mEntitleMgr);
+        mUNM.startObserveAllNetworks();
+        // Setup wifi and make wifi as default network.
+        final TestNetworkAgent wifiAgent = new TestNetworkAgent(mCM, TRANSPORT_WIFI);
+        wifiAgent.fakeConnect();
+        mCM.makeDefaultNetwork(wifiAgent);
+        // Setup mobile network.
+        final TestNetworkAgent cellAgent = new TestNetworkAgent(mCM, TRANSPORT_CELLULAR);
+        cellAgent.fakeConnect();
+
+        assertSatisfiesLegacyType(TYPE_MOBILE_HIPRI,
+                mUNM.selectPreferredUpstreamType(preferredTypes));
+        verify(mEntitleMgr, times(1)).maybeRunProvisioning();
+    }
+
+    private void assertSatisfiesLegacyType(int legacyType, UpstreamNetworkState ns) {
+        if (legacyType == TYPE_NONE) {
+            assertTrue(ns == null);
+            return;
+        }
+
+        final NetworkCapabilities nc =
+                UpstreamNetworkMonitor.networkCapabilitiesForType(legacyType);
+        assertTrue(nc.satisfiedByNetworkCapabilities(ns.networkCapabilities));
+    }
+
+    private void assertUpstreamTypeRequested(int upstreamType) throws Exception {
+        assertEquals(1, mCM.requested.size());
+        assertEquals(1, mCM.legacyTypeMap.size());
+        assertEquals(Integer.valueOf(upstreamType),
+                mCM.legacyTypeMap.values().iterator().next());
+    }
+
+    private boolean isDunRequested() {
+        for (NetworkRequest req : mCM.requested.values()) {
+            if (req.networkCapabilities.hasCapability(NET_CAPABILITY_DUN)) {
+                return true;
+            }
+        }
+        return false;
+    }
+
+    public static class TestConnectivityManager extends ConnectivityManager {
+        public Map<NetworkCallback, Handler> allCallbacks = new HashMap<>();
+        public Set<NetworkCallback> trackingDefault = new HashSet<>();
+        public TestNetworkAgent defaultNetwork = null;
+        public Map<NetworkCallback, NetworkRequest> listening = new HashMap<>();
+        public Map<NetworkCallback, NetworkRequest> requested = new HashMap<>();
+        public Map<NetworkCallback, Integer> legacyTypeMap = new HashMap<>();
+
+        private int mNetworkId = 100;
+
+        public TestConnectivityManager(Context ctx, IConnectivityManager svc) {
+            super(ctx, svc);
+        }
+
+        boolean hasNoCallbacks() {
+            return allCallbacks.isEmpty()
+                    && trackingDefault.isEmpty()
+                    && listening.isEmpty()
+                    && requested.isEmpty()
+                    && legacyTypeMap.isEmpty();
+        }
+
+        boolean onlyHasDefaultCallbacks() {
+            return (allCallbacks.size() == 1)
+                    && (trackingDefault.size() == 1)
+                    && listening.isEmpty()
+                    && requested.isEmpty()
+                    && legacyTypeMap.isEmpty();
+        }
+
+        boolean isListeningForAll() {
+            final NetworkCapabilities empty = new NetworkCapabilities();
+            empty.clearAll();
+
+            for (NetworkRequest req : listening.values()) {
+                if (req.networkCapabilities.equalRequestableCapabilities(empty)) {
+                    return true;
+                }
+            }
+            return false;
+        }
+
+        int getNetworkId() {
+            return ++mNetworkId;
+        }
+
+        void makeDefaultNetwork(TestNetworkAgent agent) {
+            if (Objects.equals(defaultNetwork, agent)) return;
+
+            final TestNetworkAgent formerDefault = defaultNetwork;
+            defaultNetwork = agent;
+
+            for (NetworkCallback cb : trackingDefault) {
+                if (defaultNetwork != null) {
+                    cb.onAvailable(defaultNetwork.networkId);
+                    cb.onCapabilitiesChanged(
+                            defaultNetwork.networkId, defaultNetwork.networkCapabilities);
+                    cb.onLinkPropertiesChanged(
+                            defaultNetwork.networkId, defaultNetwork.linkProperties);
+                }
+            }
+        }
+
+        @Override
+        public void requestNetwork(NetworkRequest req, NetworkCallback cb, Handler h) {
+            assertFalse(allCallbacks.containsKey(cb));
+            allCallbacks.put(cb, h);
+            if (sDefaultRequest.equals(req)) {
+                assertFalse(trackingDefault.contains(cb));
+                trackingDefault.add(cb);
+            } else {
+                assertFalse(requested.containsKey(cb));
+                requested.put(cb, req);
+            }
+        }
+
+        @Override
+        public void requestNetwork(NetworkRequest req, NetworkCallback cb) {
+            fail("Should never be called.");
+        }
+
+        @Override
+        public void requestNetwork(NetworkRequest req,
+                int timeoutMs, int legacyType, Handler h, NetworkCallback cb) {
+            assertFalse(allCallbacks.containsKey(cb));
+            allCallbacks.put(cb, h);
+            assertFalse(requested.containsKey(cb));
+            requested.put(cb, req);
+            assertFalse(legacyTypeMap.containsKey(cb));
+            if (legacyType != ConnectivityManager.TYPE_NONE) {
+                legacyTypeMap.put(cb, legacyType);
+            }
+        }
+
+        @Override
+        public void registerNetworkCallback(NetworkRequest req, NetworkCallback cb, Handler h) {
+            assertFalse(allCallbacks.containsKey(cb));
+            allCallbacks.put(cb, h);
+            assertFalse(listening.containsKey(cb));
+            listening.put(cb, req);
+        }
+
+        @Override
+        public void registerNetworkCallback(NetworkRequest req, NetworkCallback cb) {
+            fail("Should never be called.");
+        }
+
+        @Override
+        public void registerDefaultNetworkCallback(NetworkCallback cb, Handler h) {
+            fail("Should never be called.");
+        }
+
+        @Override
+        public void registerDefaultNetworkCallback(NetworkCallback cb) {
+            fail("Should never be called.");
+        }
+
+        @Override
+        public void unregisterNetworkCallback(NetworkCallback cb) {
+            if (trackingDefault.contains(cb)) {
+                trackingDefault.remove(cb);
+            } else if (listening.containsKey(cb)) {
+                listening.remove(cb);
+            } else if (requested.containsKey(cb)) {
+                requested.remove(cb);
+                legacyTypeMap.remove(cb);
+            } else {
+                fail("Unexpected callback removed");
+            }
+            allCallbacks.remove(cb);
+
+            assertFalse(allCallbacks.containsKey(cb));
+            assertFalse(trackingDefault.contains(cb));
+            assertFalse(listening.containsKey(cb));
+            assertFalse(requested.containsKey(cb));
+        }
+    }
+
+    public static class TestNetworkAgent {
+        public final TestConnectivityManager cm;
+        public final Network networkId;
+        public final int transportType;
+        public final NetworkCapabilities networkCapabilities;
+        public final LinkProperties linkProperties;
+
+        public TestNetworkAgent(TestConnectivityManager cm, int transportType) {
+            this.cm = cm;
+            this.networkId = new Network(cm.getNetworkId());
+            this.transportType = transportType;
+            networkCapabilities = new NetworkCapabilities();
+            networkCapabilities.addTransportType(transportType);
+            networkCapabilities.addCapability(NET_CAPABILITY_INTERNET);
+            linkProperties = new LinkProperties();
+        }
+
+        public void fakeConnect() {
+            for (NetworkCallback cb : cm.listening.keySet()) {
+                cb.onAvailable(networkId);
+                cb.onCapabilitiesChanged(networkId, copy(networkCapabilities));
+                cb.onLinkPropertiesChanged(networkId, copy(linkProperties));
+            }
+        }
+
+        public void fakeDisconnect() {
+            for (NetworkCallback cb : cm.listening.keySet()) {
+                cb.onLost(networkId);
+            }
+        }
+
+        public void sendLinkProperties() {
+            for (NetworkCallback cb : cm.listening.keySet()) {
+                cb.onLinkPropertiesChanged(networkId, copy(linkProperties));
+            }
+        }
+
+        @Override
+        public String toString() {
+            return String.format("TestNetworkAgent: %s %s", networkId, networkCapabilities);
+        }
+    }
+
+    public static class TestStateMachine extends StateMachine {
+        public final ArrayList<Message> messages = new ArrayList<>();
+        private final State mLoggingState = new LoggingState();
+
+        class LoggingState extends State {
+            @Override public void enter() {
+                messages.clear();
+            }
+
+            @Override public void exit() {
+                messages.clear();
+            }
+
+            @Override public boolean processMessage(Message msg) {
+                messages.add(msg);
+                return true;
+            }
+        }
+
+        public TestStateMachine() {
+            super("UpstreamNetworkMonitor.TestStateMachine");
+            addState(mLoggingState);
+            setInitialState(mLoggingState);
+            super.start();
+        }
+    }
+
+    static NetworkCapabilities copy(NetworkCapabilities nc) {
+        return new NetworkCapabilities(nc);
+    }
+
+    static LinkProperties copy(LinkProperties lp) {
+        return new LinkProperties(lp);
+    }
+
+    static void assertPrefixSet(Set<IpPrefix> prefixes, boolean expectation, String... expected) {
+        final Set<String> expectedSet = new HashSet<>();
+        Collections.addAll(expectedSet, expected);
+        assertPrefixSet(prefixes, expectation, expectedSet);
+    }
+
+    static void assertPrefixSet(Set<IpPrefix> prefixes, boolean expectation, Set<String> expected) {
+        for (String expectedPrefix : expected) {
+            final String errStr = expectation ? "did not find" : "found";
+            assertEquals(
+                    String.format("Failed expectation: %s prefix: %s", errStr, expectedPrefix),
+                    expectation, prefixes.contains(new IpPrefix(expectedPrefix)));
+        }
+    }
+}