[CLATJ#7] ClatCoordinator: select IPv4 address for clatd
Introduce ClatCoordinator to replace netd/ClatdController.
This is a startup commit. Starting clatd needs to prepare local
464xlat ipv4 address, local 464xlat ipv6 address, tun interface,
clat read/write sockets. These will be implemented from this
and followup commits. This commit implements that prepare local
464xlat ipv4 address.
Bug: 212345928
Test: flash and boot
Run "atest ClatCoordinatorTest" in a followup commit.
Change-Id: I486db8aef0181ee1aedd7cd7702f95d5a1cef812
diff --git a/service/Android.bp b/service/Android.bp
index 76f9153..5ba6a00 100644
--- a/service/Android.bp
+++ b/service/Android.bp
@@ -57,12 +57,18 @@
],
srcs: [
"jni/com_android_server_TestNetworkService.cpp",
+ "jni/com_android_server_connectivity_ClatCoordinator.cpp",
"jni/onload.cpp",
],
stl: "libc++_static",
header_libs: [
"libbase_headers",
],
+ static_libs: [
+ "libclat",
+ "libip_checksum",
+ "libnetjniutils",
+ ],
shared_libs: [
"liblog",
"libnativehelper",
diff --git a/service/jni/com_android_server_connectivity_ClatCoordinator.cpp b/service/jni/com_android_server_connectivity_ClatCoordinator.cpp
new file mode 100644
index 0000000..e042bf3
--- /dev/null
+++ b/service/jni/com_android_server_connectivity_ClatCoordinator.cpp
@@ -0,0 +1,69 @@
+/*
+ * Copyright (C) 2022 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT 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 <arpa/inet.h>
+#include <nativehelper/JNIHelp.h>
+
+#include <netjniutils/netjniutils.h>
+
+#include "libclat/clatutils.h"
+#include "nativehelper/scoped_utf_chars.h"
+
+namespace android {
+jstring com_android_server_connectivity_ClatCoordinator_selectIpv4Address(JNIEnv* env,
+ jobject clazz,
+ jstring v4addr,
+ jint prefixlen) {
+ ScopedUtfChars address(env, v4addr);
+ in_addr ip;
+ if (inet_pton(AF_INET, address.c_str(), &ip) != 1) {
+ return nullptr;
+ }
+
+ // Pick an IPv4 address.
+ // TODO: this picks the address based on other addresses that are assigned to interfaces, but
+ // the address is only actually assigned to an interface once clatd starts up. So we could end
+ // up with two clatd instances with the same IPv4 address.
+ // Stop doing this and instead pick a free one from the kV4Addr pool.
+ in_addr v4 = {net::clat::selectIpv4Address(ip, prefixlen)};
+ if (v4.s_addr == INADDR_NONE) {
+ jniThrowExceptionFmt(env, "java/io/IOException", "No free IPv4 address in %s/%d",
+ address.c_str(), prefixlen);
+ return nullptr;
+ }
+
+ char addrstr[INET_ADDRSTRLEN];
+ if (!inet_ntop(AF_INET, (void*)&v4, addrstr, sizeof(addrstr))) {
+ return nullptr;
+ }
+ return env->NewStringUTF(addrstr);
+}
+
+/*
+ * JNI registration.
+ */
+static const JNINativeMethod gMethods[] = {
+ /* name, signature, funcPtr */
+ {"selectIpv4Address", "(Ljava/lang/String;I)Ljava/lang/String;",
+ (void*)com_android_server_connectivity_ClatCoordinator_selectIpv4Address},
+};
+
+int register_android_server_connectivity_ClatCoordinator(JNIEnv* env) {
+ return jniRegisterNativeMethods(env, "com/android/server/connectivity/ClatCoordinator",
+ gMethods, NELEM(gMethods));
+}
+
+}; // namespace android
diff --git a/service/jni/onload.cpp b/service/jni/onload.cpp
index 0012879..04d9671 100644
--- a/service/jni/onload.cpp
+++ b/service/jni/onload.cpp
@@ -20,6 +20,7 @@
namespace android {
int register_android_server_TestNetworkService(JNIEnv* env);
+int register_android_server_connectivity_ClatCoordinator(JNIEnv* env);
extern "C" jint JNI_OnLoad(JavaVM* vm, void*) {
JNIEnv *env;
@@ -32,6 +33,10 @@
return JNI_ERR;
}
+ if (register_android_server_connectivity_ClatCoordinator(env) < 0) {
+ return JNI_ERR;
+ }
+
return JNI_VERSION_1_6;
}
diff --git a/service/src/com/android/server/connectivity/ClatCoordinator.java b/service/src/com/android/server/connectivity/ClatCoordinator.java
new file mode 100644
index 0000000..cf22e24
--- /dev/null
+++ b/service/src/com/android/server/connectivity/ClatCoordinator.java
@@ -0,0 +1,100 @@
+/*
+ * Copyright (C) 2022 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT 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.server.connectivity;
+
+import android.annotation.NonNull;
+import android.annotation.Nullable;
+import android.net.INetd;
+import android.net.IpPrefix;
+
+import com.android.internal.annotations.VisibleForTesting;
+
+import java.io.IOException;
+
+/**
+ * This coordinator is responsible for providing clat relevant functionality.
+ *
+ * {@hide}
+ */
+public class ClatCoordinator {
+ private static final String TAG = ClatCoordinator.class.getSimpleName();
+
+ // For historical reasons, start with 192.0.0.4, and after that, use all subsequent addresses
+ // in 192.0.0.0/29 (RFC 7335).
+ @VisibleForTesting
+ static final String INIT_V4ADDR_STRING = "192.0.0.4";
+ @VisibleForTesting
+ static final int INIT_V4ADDR_PREFIX_LEN = 29;
+
+ private static final int INVALID_PID = 0;
+
+ @NonNull
+ private final INetd mNetd;
+ @NonNull
+ private final Dependencies mDeps;
+ @Nullable
+ private String mIface = null;
+ private int mPid = INVALID_PID;
+
+ @VisibleForTesting
+ abstract static class Dependencies {
+ /**
+ * Get netd.
+ */
+ @NonNull
+ public abstract INetd getNetd();
+
+ /**
+ * Pick an IPv4 address for clat.
+ */
+ @NonNull
+ public String jniSelectIpv4Address(@NonNull String v4addr, int prefixlen)
+ throws IOException {
+ return selectIpv4Address(v4addr, prefixlen);
+ }
+ }
+
+ public ClatCoordinator(@NonNull Dependencies deps) {
+ mDeps = deps;
+ mNetd = mDeps.getNetd();
+ }
+
+ /**
+ * Start clatd for a given interface and NAT64 prefix.
+ */
+ public String clatStart(final String iface, final int netId,
+ @NonNull final IpPrefix nat64Prefix)
+ throws IOException {
+ if (nat64Prefix.getPrefixLength() != 96) {
+ throw new IOException("Prefix must be 96 bits long: " + nat64Prefix);
+ }
+
+ // [1] Pick an IPv4 address from 192.0.0.4, 192.0.0.5, 192.0.0.6 ..
+ final String v4;
+ try {
+ v4 = mDeps.jniSelectIpv4Address(INIT_V4ADDR_STRING, INIT_V4ADDR_PREFIX_LEN);
+ } catch (IOException e) {
+ throw new IOException("no IPv4 addresses were available for clat: " + e);
+ }
+
+ // TODO: start clatd and returns local xlat464 v6 address.
+ return null;
+ }
+
+ private static native String selectIpv4Address(String v4addr, int prefixlen)
+ throws IOException;
+}