Merge "Remove useless methods from NetworkStatsRecorder"
diff --git a/Tethering/Android.bp b/Tethering/Android.bp
index 026ed54..adcc236 100644
--- a/Tethering/Android.bp
+++ b/Tethering/Android.bp
@@ -21,7 +21,7 @@
 java_defaults {
     name: "TetheringApiLevel",
     sdk_version: "module_current",
-    target_sdk_version: "31",
+    target_sdk_version: "33",
     min_sdk_version: "30",
 }
 
diff --git a/Tethering/tests/integration/Android.bp b/Tethering/tests/integration/Android.bp
index a4d0448..31c3df3 100644
--- a/Tethering/tests/integration/Android.bp
+++ b/Tethering/tests/integration/Android.bp
@@ -49,7 +49,7 @@
 // Use with NetworkStackJarJarRules.
 android_library {
     name: "TetheringIntegrationTestsLatestSdkLib",
-    target_sdk_version: "31",
+    target_sdk_version: "33",
     platform_apis: true,
     defaults: ["TetheringIntegrationTestsDefaults"],
     visibility: [
diff --git a/Tethering/tests/mts/Android.bp b/Tethering/tests/mts/Android.bp
index 18fd63b..a84fdd2 100644
--- a/Tethering/tests/mts/Android.bp
+++ b/Tethering/tests/mts/Android.bp
@@ -22,7 +22,7 @@
     name: "MtsTetheringTestLatestSdk",
 
     min_sdk_version: "30",
-    target_sdk_version: "31",
+    target_sdk_version: "33",
 
     libs: [
         "android.test.base",
diff --git a/Tethering/tests/unit/Android.bp b/Tethering/tests/unit/Android.bp
index d1b8380..0ee12ad 100644
--- a/Tethering/tests/unit/Android.bp
+++ b/Tethering/tests/unit/Android.bp
@@ -89,7 +89,7 @@
     static_libs: [
         "TetheringApiStableLib",
     ],
-    target_sdk_version: "31",
+    target_sdk_version: "33",
     visibility: [
         "//packages/modules/Connectivity/tests:__subpackages__",
         "//packages/modules/Connectivity/Tethering/tests:__subpackages__",
diff --git a/framework-t/src/android/net/nsd/NsdManager.java b/framework-t/src/android/net/nsd/NsdManager.java
index 33b44c8..5dcc40f 100644
--- a/framework-t/src/android/net/nsd/NsdManager.java
+++ b/framework-t/src/android/net/nsd/NsdManager.java
@@ -175,6 +175,7 @@
      *
      * @see #ACTION_NSD_STATE_CHANGED
      */
+    // TODO: Deprecate this since NSD service is never disabled.
     public static final int NSD_STATE_DISABLED = 1;
 
     /**
@@ -230,17 +231,12 @@
     public static final int DAEMON_STARTUP                          = 19;
 
     /** @hide */
-    public static final int ENABLE                                  = 20;
-    /** @hide */
-    public static final int DISABLE                                 = 21;
+    public static final int MDNS_SERVICE_EVENT                      = 20;
 
     /** @hide */
-    public static final int MDNS_SERVICE_EVENT                      = 22;
-
+    public static final int REGISTER_CLIENT                         = 21;
     /** @hide */
-    public static final int REGISTER_CLIENT                         = 23;
-    /** @hide */
-    public static final int UNREGISTER_CLIENT                       = 24;
+    public static final int UNREGISTER_CLIENT                       = 22;
 
     /** Dns based service discovery protocol */
     public static final int PROTOCOL_DNS_SD = 0x0001;
@@ -266,8 +262,6 @@
         EVENT_NAMES.put(RESOLVE_SERVICE_SUCCEEDED, "RESOLVE_SERVICE_SUCCEEDED");
         EVENT_NAMES.put(DAEMON_CLEANUP, "DAEMON_CLEANUP");
         EVENT_NAMES.put(DAEMON_STARTUP, "DAEMON_STARTUP");
-        EVENT_NAMES.put(ENABLE, "ENABLE");
-        EVENT_NAMES.put(DISABLE, "DISABLE");
         EVENT_NAMES.put(MDNS_SERVICE_EVENT, "MDNS_SERVICE_EVENT");
     }
 
diff --git a/netd/BpfHandlerTest.cpp b/netd/BpfHandlerTest.cpp
index 12ae916..1bd222d 100644
--- a/netd/BpfHandlerTest.cpp
+++ b/netd/BpfHandlerTest.cpp
@@ -21,6 +21,7 @@
 
 #include <gtest/gtest.h>
 
+#define TEST_BPF_MAP
 #include "BpfHandler.h"
 
 using namespace android::bpf;  // NOLINT(google-build-using-namespace): exempted
@@ -55,39 +56,31 @@
         std::lock_guard guard(mBh.mMutex);
         ASSERT_EQ(0, setrlimitForTest());
 
-        mFakeCookieTagMap.reset(createMap(BPF_MAP_TYPE_HASH, sizeof(uint64_t), sizeof(UidTagValue),
-                                          TEST_MAP_SIZE, 0));
+        mFakeCookieTagMap.resetMap(BPF_MAP_TYPE_HASH, TEST_MAP_SIZE);
         ASSERT_VALID(mFakeCookieTagMap);
 
-        mFakeStatsMapA.reset(createMap(BPF_MAP_TYPE_HASH, sizeof(StatsKey), sizeof(StatsValue),
-                                       TEST_MAP_SIZE, 0));
+        mFakeStatsMapA.resetMap(BPF_MAP_TYPE_HASH, TEST_MAP_SIZE);
         ASSERT_VALID(mFakeStatsMapA);
 
-        mFakeConfigurationMap.reset(
-                createMap(BPF_MAP_TYPE_HASH, sizeof(uint32_t), sizeof(uint8_t), 1, 0));
+        mFakeConfigurationMap.resetMap(BPF_MAP_TYPE_HASH, 1);
         ASSERT_VALID(mFakeConfigurationMap);
 
-        mFakeUidPermissionMap.reset(
-                createMap(BPF_MAP_TYPE_HASH, sizeof(uint32_t), sizeof(uint8_t), TEST_MAP_SIZE, 0));
+        mFakeUidPermissionMap.resetMap(BPF_MAP_TYPE_HASH, TEST_MAP_SIZE, 0);
         ASSERT_VALID(mFakeUidPermissionMap);
 
-        mBh.mCookieTagMap.reset(dupFd(mFakeCookieTagMap.getMap()));
+        mBh.mCookieTagMap = mFakeCookieTagMap;
         ASSERT_VALID(mBh.mCookieTagMap);
-        mBh.mStatsMapA.reset(dupFd(mFakeStatsMapA.getMap()));
+        mBh.mStatsMapA = mFakeStatsMapA;
         ASSERT_VALID(mBh.mStatsMapA);
-        mBh.mConfigurationMap.reset(dupFd(mFakeConfigurationMap.getMap()));
+        mBh.mConfigurationMap = mFakeConfigurationMap;
         ASSERT_VALID(mBh.mConfigurationMap);
         // Always write to stats map A by default.
         ASSERT_RESULT_OK(mBh.mConfigurationMap.writeValue(CURRENT_STATS_MAP_CONFIGURATION_KEY,
                                                           SELECT_MAP_A, BPF_ANY));
-        mBh.mUidPermissionMap.reset(dupFd(mFakeUidPermissionMap.getMap()));
+        mBh.mUidPermissionMap = mFakeUidPermissionMap;
         ASSERT_VALID(mBh.mUidPermissionMap);
     }
 
-    int dupFd(const android::base::unique_fd& mapFd) {
-        return fcntl(mapFd.get(), F_DUPFD_CLOEXEC, 0);
-    }
-
     int setUpSocketAndTag(int protocol, uint64_t* cookie, uint32_t tag, uid_t uid,
                           uid_t realUid) {
         int sock = socket(protocol, SOCK_STREAM | SOCK_CLOEXEC, 0);
diff --git a/service-t/src/com/android/server/NsdService.java b/service-t/src/com/android/server/NsdService.java
index 95e6114..7115720 100644
--- a/service-t/src/com/android/server/NsdService.java
+++ b/service-t/src/com/android/server/NsdService.java
@@ -101,7 +101,6 @@
     private class NsdStateMachine extends StateMachine {
 
         private final DefaultState mDefaultState = new DefaultState();
-        private final DisabledState mDisabledState = new DisabledState();
         private final EnabledState mEnabledState = new EnabledState();
 
         @Override
@@ -152,7 +151,6 @@
         NsdStateMachine(String name, Handler handler) {
             super(name, handler);
             addState(mDefaultState);
-                addState(mDisabledState, mDefaultState);
                 addState(mEnabledState, mDefaultState);
             State initialState = mEnabledState;
             setInitialState(initialState);
@@ -250,25 +248,6 @@
             }
         }
 
-        class DisabledState extends State {
-            @Override
-            public void enter() {
-                sendNsdStateChangeBroadcast(false);
-            }
-
-            @Override
-            public boolean processMessage(Message msg) {
-                switch (msg.what) {
-                    case NsdManager.ENABLE:
-                        transitionTo(mEnabledState);
-                        break;
-                    default:
-                        return NOT_HANDLED;
-                }
-                return HANDLED;
-            }
-        }
-
         class EnabledState extends State {
             @Override
             public void enter() {
@@ -312,10 +291,6 @@
                 final int clientId = msg.arg2;
                 final ListenerArgs args;
                 switch (msg.what) {
-                    case NsdManager.DISABLE:
-                        //TODO: cleanup clients
-                        transitionTo(mDisabledState);
-                        break;
                     case NsdManager.DISCOVER_SERVICES:
                         if (DBG) Log.d(TAG, "Discover services");
                         args = (ListenerArgs) msg.obj;
diff --git a/service/native/TrafficControllerTest.cpp b/service/native/TrafficControllerTest.cpp
index 96bd57c..fb18f35 100644
--- a/service/native/TrafficControllerTest.cpp
+++ b/service/native/TrafficControllerTest.cpp
@@ -36,6 +36,7 @@
 
 #include <netdutils/MockSyscalls.h>
 
+#define TEST_BPF_MAP
 #include "TrafficController.h"
 #include "bpf/BpfUtils.h"
 #include "NetdUpdatablePublic.h"
@@ -73,52 +74,42 @@
         std::lock_guard guard(mTc.mMutex);
         ASSERT_EQ(0, setrlimitForTest());
 
-        mFakeCookieTagMap.reset(createMap(BPF_MAP_TYPE_HASH, sizeof(uint64_t), sizeof(UidTagValue),
-                                          TEST_MAP_SIZE, 0));
+        mFakeCookieTagMap.resetMap(BPF_MAP_TYPE_HASH, TEST_MAP_SIZE);
         ASSERT_VALID(mFakeCookieTagMap);
 
-        mFakeAppUidStatsMap.reset(createMap(BPF_MAP_TYPE_HASH, sizeof(uint32_t), sizeof(StatsValue),
-                                            TEST_MAP_SIZE, 0));
+        mFakeAppUidStatsMap.resetMap(BPF_MAP_TYPE_HASH, TEST_MAP_SIZE);
         ASSERT_VALID(mFakeAppUidStatsMap);
 
-        mFakeStatsMapA.reset(createMap(BPF_MAP_TYPE_HASH, sizeof(StatsKey), sizeof(StatsValue),
-                                       TEST_MAP_SIZE, 0));
+        mFakeStatsMapA.resetMap(BPF_MAP_TYPE_HASH, TEST_MAP_SIZE);
         ASSERT_VALID(mFakeStatsMapA);
 
-        mFakeConfigurationMap.reset(
-                createMap(BPF_MAP_TYPE_HASH, sizeof(uint32_t), sizeof(uint8_t), 1, 0));
+        mFakeConfigurationMap.resetMap(BPF_MAP_TYPE_HASH, 1);
         ASSERT_VALID(mFakeConfigurationMap);
 
-        mFakeUidOwnerMap.reset(createMap(BPF_MAP_TYPE_HASH, sizeof(uint32_t), sizeof(UidOwnerValue),
-                                         TEST_MAP_SIZE, 0));
+        mFakeUidOwnerMap.resetMap(BPF_MAP_TYPE_HASH, TEST_MAP_SIZE);
         ASSERT_VALID(mFakeUidOwnerMap);
-        mFakeUidPermissionMap.reset(
-                createMap(BPF_MAP_TYPE_HASH, sizeof(uint32_t), sizeof(uint8_t), TEST_MAP_SIZE, 0));
+        mFakeUidPermissionMap.resetMap(BPF_MAP_TYPE_HASH, TEST_MAP_SIZE);
         ASSERT_VALID(mFakeUidPermissionMap);
 
-        mTc.mCookieTagMap.reset(dupFd(mFakeCookieTagMap.getMap()));
+        mTc.mCookieTagMap = mFakeCookieTagMap;
         ASSERT_VALID(mTc.mCookieTagMap);
-        mTc.mAppUidStatsMap.reset(dupFd(mFakeAppUidStatsMap.getMap()));
+        mTc.mAppUidStatsMap = mFakeAppUidStatsMap;
         ASSERT_VALID(mTc.mAppUidStatsMap);
-        mTc.mStatsMapA.reset(dupFd(mFakeStatsMapA.getMap()));
+        mTc.mStatsMapA = mFakeStatsMapA;
         ASSERT_VALID(mTc.mStatsMapA);
-        mTc.mConfigurationMap.reset(dupFd(mFakeConfigurationMap.getMap()));
+        mTc.mConfigurationMap = mFakeConfigurationMap;
         ASSERT_VALID(mTc.mConfigurationMap);
 
         // Always write to stats map A by default.
         ASSERT_RESULT_OK(mTc.mConfigurationMap.writeValue(CURRENT_STATS_MAP_CONFIGURATION_KEY,
                                                           SELECT_MAP_A, BPF_ANY));
-        mTc.mUidOwnerMap.reset(dupFd(mFakeUidOwnerMap.getMap()));
+        mTc.mUidOwnerMap = mFakeUidOwnerMap;
         ASSERT_VALID(mTc.mUidOwnerMap);
-        mTc.mUidPermissionMap.reset(dupFd(mFakeUidPermissionMap.getMap()));
+        mTc.mUidPermissionMap = mFakeUidPermissionMap;
         ASSERT_VALID(mTc.mUidPermissionMap);
         mTc.mPrivilegedUser.clear();
     }
 
-    int dupFd(const android::base::unique_fd& mapFd) {
-        return fcntl(mapFd.get(), F_DUPFD_CLOEXEC, 0);
-    }
-
     void populateFakeStats(uint64_t cookie, uint32_t uid, uint32_t tag, StatsKey* key) {
         UidTagValue cookieMapkey = {.uid = (uint32_t)uid, .tag = tag};
         EXPECT_RESULT_OK(mFakeCookieTagMap.writeValue(cookie, cookieMapkey, BPF_ANY));
@@ -673,7 +664,7 @@
     BpfMap<uint64_t, UidTagValue> mCookieTagMap;
 
     void SetUp() {
-        mCookieTagMap.reset(android::bpf::mapRetrieveRW(COOKIE_TAG_MAP_PATH));
+        mCookieTagMap.init(COOKIE_TAG_MAP_PATH);
         ASSERT_TRUE(mCookieTagMap.isValid());
     }
 
diff --git a/service/native/libs/libclat/Android.bp b/service/native/libs/libclat/Android.bp
index 68e4dc4..54d40ac 100644
--- a/service/native/libs/libclat/Android.bp
+++ b/service/native/libs/libclat/Android.bp
@@ -35,7 +35,8 @@
 cc_test {
     name: "libclat_test",
     defaults: ["netd_defaults"],
-    test_suites: ["device-tests"],
+    test_suites: ["general-tests", "mts-tethering"],
+    test_config_template: ":net_native_test_config_template",
     srcs: [
         "clatutils_test.cpp",
     ],
@@ -49,5 +50,14 @@
         "liblog",
         "libnetutils",
     ],
+    compile_multilib: "both",
+    multilib: {
+        lib32: {
+            suffix: "32",
+        },
+        lib64: {
+            suffix: "64",
+        },
+    },
     require_root: true,
 }
diff --git a/service/src/com/android/server/net/DelayedDiskWrite.java b/service/src/com/android/server/net/DelayedDiskWrite.java
index 35dc455..41cb419 100644
--- a/service/src/com/android/server/net/DelayedDiskWrite.java
+++ b/service/src/com/android/server/net/DelayedDiskWrite.java
@@ -21,6 +21,8 @@
 import android.text.TextUtils;
 import android.util.Log;
 
+import com.android.internal.annotations.VisibleForTesting;
+
 import java.io.BufferedOutputStream;
 import java.io.DataOutputStream;
 import java.io.FileOutputStream;
@@ -32,11 +34,42 @@
 public class DelayedDiskWrite {
     private static final String TAG = "DelayedDiskWrite";
 
+    private final Dependencies mDeps;
+
     private HandlerThread mDiskWriteHandlerThread;
     private Handler mDiskWriteHandler;
     /* Tracks multiple writes on the same thread */
     private int mWriteSequence = 0;
 
+    public DelayedDiskWrite() {
+        this(new Dependencies());
+    }
+
+    @VisibleForTesting
+    DelayedDiskWrite(Dependencies deps) {
+        mDeps = deps;
+    }
+
+    /**
+     * Dependencies class of DelayedDiskWrite, used for injection in tests.
+     */
+    @VisibleForTesting
+    static class Dependencies {
+        /**
+         * Create a HandlerThread to use in DelayedDiskWrite.
+         */
+        public HandlerThread makeHandlerThread() {
+            return new HandlerThread("DelayedDiskWriteThread");
+        }
+
+        /**
+         * Quit the HandlerThread looper.
+         */
+        public void quitHandlerThread(HandlerThread handlerThread) {
+            handlerThread.getLooper().quit();
+        }
+    }
+
     /**
      * Used to do a delayed data write to a given {@link OutputStream}.
      */
@@ -65,7 +98,7 @@
         /* Do a delayed write to disk on a separate handler thread */
         synchronized (this) {
             if (++mWriteSequence == 1) {
-                mDiskWriteHandlerThread = new HandlerThread("DelayedDiskWriteThread");
+                mDiskWriteHandlerThread = mDeps.makeHandlerThread();
                 mDiskWriteHandlerThread.start();
                 mDiskWriteHandler = new Handler(mDiskWriteHandlerThread.getLooper());
             }
@@ -99,9 +132,9 @@
             // Quit if no more writes sent
             synchronized (this) {
                 if (--mWriteSequence == 0) {
-                    mDiskWriteHandler.getLooper().quit();
-                    mDiskWriteHandler = null;
+                    mDeps.quitHandlerThread(mDiskWriteHandlerThread);
                     mDiskWriteHandlerThread = null;
+                    mDiskWriteHandler = null;
                 }
             }
         }
diff --git a/tests/cts/tethering/Android.bp b/tests/cts/tethering/Android.bp
index e9c4e5a..6096a8b 100644
--- a/tests/cts/tethering/Android.bp
+++ b/tests/cts/tethering/Android.bp
@@ -56,7 +56,7 @@
     defaults: ["CtsTetheringTestDefaults"],
 
     min_sdk_version: "30",
-    target_sdk_version: "30",
+    target_sdk_version: "33",
 
     static_libs: [
         "TetheringIntegrationTestsLatestSdkLib",
diff --git a/tests/unit/java/com/android/server/net/IpConfigStoreTest.java b/tests/unit/java/com/android/server/net/IpConfigStoreTest.java
index 1801c45..4adc999 100644
--- a/tests/unit/java/com/android/server/net/IpConfigStoreTest.java
+++ b/tests/unit/java/com/android/server/net/IpConfigStoreTest.java
@@ -20,6 +20,7 @@
 import static org.junit.Assert.assertNotNull;
 import static org.junit.Assert.fail;
 
+import android.content.Context;
 import android.net.InetAddresses;
 import android.net.IpConfiguration;
 import android.net.IpConfiguration.IpAssignment;
@@ -28,10 +29,14 @@
 import android.net.ProxyInfo;
 import android.net.StaticIpConfiguration;
 import android.os.Build;
+import android.os.HandlerThread;
 import android.util.ArrayMap;
 
+import androidx.test.InstrumentationRegistry;
+
 import com.android.testutils.DevSdkIgnoreRule;
 import com.android.testutils.DevSdkIgnoreRunner;
+import com.android.testutils.HandlerUtils;
 
 import org.junit.Test;
 import org.junit.runner.RunWith;
@@ -39,11 +44,13 @@
 import java.io.ByteArrayInputStream;
 import java.io.ByteArrayOutputStream;
 import java.io.DataOutputStream;
+import java.io.File;
 import java.io.IOException;
 import java.io.InputStream;
 import java.net.InetAddress;
 import java.util.ArrayList;
 import java.util.Arrays;
+import java.util.List;
 
 /**
  * Unit tests for {@link IpConfigStore}
@@ -51,6 +58,7 @@
 @RunWith(DevSdkIgnoreRunner.class)
 @DevSdkIgnoreRule.IgnoreUpTo(Build.VERSION_CODES.S_V2)
 public class IpConfigStoreTest {
+    private static final int TIMEOUT_MS = 2_000;
     private static final int KEY_CONFIG = 17;
     private static final String IFACE_1 = "eth0";
     private static final String IFACE_2 = "eth1";
@@ -59,6 +67,22 @@
     private static final String DNS_IP_ADDR_1 = "1.2.3.4";
     private static final String DNS_IP_ADDR_2 = "5.6.7.8";
 
+    private static final ArrayList<InetAddress> DNS_SERVERS = new ArrayList<>(List.of(
+            InetAddresses.parseNumericAddress(DNS_IP_ADDR_1),
+            InetAddresses.parseNumericAddress(DNS_IP_ADDR_2)));
+    private static final StaticIpConfiguration STATIC_IP_CONFIG_1 =
+            new StaticIpConfiguration.Builder()
+                    .setIpAddress(new LinkAddress(IP_ADDR_1))
+                    .setDnsServers(DNS_SERVERS)
+                    .build();
+    private static final StaticIpConfiguration STATIC_IP_CONFIG_2 =
+            new StaticIpConfiguration.Builder()
+                    .setIpAddress(new LinkAddress(IP_ADDR_2))
+                    .setDnsServers(DNS_SERVERS)
+                    .build();
+    private static final ProxyInfo PROXY_INFO =
+            ProxyInfo.buildDirectProxy("10.10.10.10", 88, Arrays.asList("host1", "host2"));
+
     @Test
     public void backwardCompatibility2to3() throws IOException {
         ByteArrayOutputStream byteStream = new ByteArrayOutputStream();
@@ -82,40 +106,73 @@
 
     @Test
     public void staticIpMultiNetworks() throws Exception {
-        final ArrayList<InetAddress> dnsServers = new ArrayList<>();
-        dnsServers.add(InetAddresses.parseNumericAddress(DNS_IP_ADDR_1));
-        dnsServers.add(InetAddresses.parseNumericAddress(DNS_IP_ADDR_2));
-        final StaticIpConfiguration staticIpConfiguration1 = new StaticIpConfiguration.Builder()
-                .setIpAddress(new LinkAddress(IP_ADDR_1))
-                .setDnsServers(dnsServers).build();
-        final StaticIpConfiguration staticIpConfiguration2 = new StaticIpConfiguration.Builder()
-                .setIpAddress(new LinkAddress(IP_ADDR_2))
-                .setDnsServers(dnsServers).build();
+        final IpConfiguration expectedConfig1 = newIpConfiguration(IpAssignment.STATIC,
+                ProxySettings.STATIC, STATIC_IP_CONFIG_1, PROXY_INFO);
+        final IpConfiguration expectedConfig2 = newIpConfiguration(IpAssignment.STATIC,
+                ProxySettings.STATIC, STATIC_IP_CONFIG_2, PROXY_INFO);
 
-        ProxyInfo proxyInfo =
-                ProxyInfo.buildDirectProxy("10.10.10.10", 88, Arrays.asList("host1", "host2"));
-
-        IpConfiguration expectedConfig1 = newIpConfiguration(IpAssignment.STATIC,
-                ProxySettings.STATIC, staticIpConfiguration1, proxyInfo);
-        IpConfiguration expectedConfig2 = newIpConfiguration(IpAssignment.STATIC,
-                ProxySettings.STATIC, staticIpConfiguration2, proxyInfo);
-
-        ArrayMap<String, IpConfiguration> expectedNetworks = new ArrayMap<>();
+        final ArrayMap<String, IpConfiguration> expectedNetworks = new ArrayMap<>();
         expectedNetworks.put(IFACE_1, expectedConfig1);
         expectedNetworks.put(IFACE_2, expectedConfig2);
 
-        MockedDelayedDiskWrite writer = new MockedDelayedDiskWrite();
-        IpConfigStore store = new IpConfigStore(writer);
+        final MockedDelayedDiskWrite writer = new MockedDelayedDiskWrite();
+        final IpConfigStore store = new IpConfigStore(writer);
         store.writeIpConfigurations("file/path/not/used/", expectedNetworks);
 
-        InputStream in = new ByteArrayInputStream(writer.mByteStream.toByteArray());
-        ArrayMap<String, IpConfiguration> actualNetworks = IpConfigStore.readIpConfigurations(in);
+        final InputStream in = new ByteArrayInputStream(writer.mByteStream.toByteArray());
+        final ArrayMap<String, IpConfiguration> actualNetworks =
+                IpConfigStore.readIpConfigurations(in);
         assertNotNull(actualNetworks);
         assertEquals(2, actualNetworks.size());
         assertEquals(expectedNetworks.get(IFACE_1), actualNetworks.get(IFACE_1));
         assertEquals(expectedNetworks.get(IFACE_2), actualNetworks.get(IFACE_2));
     }
 
+    @Test
+    public void readIpConfigurationFromFilePath() throws Exception {
+        final HandlerThread testHandlerThread = new HandlerThread("IpConfigStoreTest");
+        final DelayedDiskWrite.Dependencies dependencies =
+                new DelayedDiskWrite.Dependencies() {
+                    @Override
+                    public HandlerThread makeHandlerThread() {
+                        return testHandlerThread;
+                    }
+                    @Override
+                    public void quitHandlerThread(HandlerThread handlerThread) {
+                        testHandlerThread.quitSafely();
+                    }
+        };
+
+        final IpConfiguration ipConfig = newIpConfiguration(IpAssignment.STATIC,
+                ProxySettings.STATIC, STATIC_IP_CONFIG_1, PROXY_INFO);
+        final ArrayMap<String, IpConfiguration> expectedNetworks = new ArrayMap<>();
+        expectedNetworks.put(IFACE_1, ipConfig);
+
+        // Write IP config to specific file path and read it later.
+        final Context context = InstrumentationRegistry.getContext();
+        final File configFile = new File(context.getFilesDir().getPath(),
+                "IpConfigStoreTest-ipconfig.txt");
+        final DelayedDiskWrite writer = new DelayedDiskWrite(dependencies);
+        final IpConfigStore store = new IpConfigStore(writer);
+        store.writeIpConfigurations(configFile.getPath(), expectedNetworks);
+        HandlerUtils.waitForIdle(testHandlerThread, TIMEOUT_MS);
+
+        // Read IP config from the file path.
+        final ArrayMap<String, IpConfiguration> actualNetworks =
+                IpConfigStore.readIpConfigurations(configFile.getPath());
+        assertNotNull(actualNetworks);
+        assertEquals(1, actualNetworks.size());
+        assertEquals(expectedNetworks.get(IFACE_1), actualNetworks.get(IFACE_1));
+
+        // Return an empty array when reading IP configuration from an non-exist config file.
+        final ArrayMap<String, IpConfiguration> emptyNetworks =
+                IpConfigStore.readIpConfigurations("/dev/null");
+        assertNotNull(emptyNetworks);
+        assertEquals(0, emptyNetworks.size());
+
+        configFile.delete();
+    }
+
     private IpConfiguration newIpConfiguration(IpAssignment ipAssignment,
             ProxySettings proxySettings, StaticIpConfiguration staticIpConfig, ProxyInfo info) {
         final IpConfiguration config = new IpConfiguration();