[Thread] request/release the NAT64 CIDR

This CL implements the logic to maintain the NAT64 CIDR at ThreadNetworkControllerService. When NAT64 is enabled, the service needs to request a CIDR via RoutingCoordinatorManager#requestDownstreamAddress(). When NAT64 is disabled, the service needs to release the CIDR via RoutingCoordinatorManager#releaseDownstreamAddress().

Bug: 350699020

Change-Id: I16397fd48c2925efd9d4833a335cf73832b4f4d6
diff --git a/thread/service/java/com/android/server/thread/ThreadNetworkControllerService.java b/thread/service/java/com/android/server/thread/ThreadNetworkControllerService.java
index 653b2fb..d5d24ac 100644
--- a/thread/service/java/com/android/server/thread/ThreadNetworkControllerService.java
+++ b/thread/service/java/com/android/server/thread/ThreadNetworkControllerService.java
@@ -78,6 +78,8 @@
 import android.content.res.Resources;
 import android.net.ConnectivityManager;
 import android.net.InetAddresses;
+import android.net.IpPrefix;
+import android.net.LinkAddress;
 import android.net.LinkProperties;
 import android.net.LocalNetworkConfig;
 import android.net.LocalNetworkInfo;
@@ -120,6 +122,8 @@
 
 import com.android.connectivity.resources.R;
 import com.android.internal.annotations.VisibleForTesting;
+import com.android.net.module.util.RoutingCoordinatorManager;
+import com.android.net.module.util.IIpv4PrefixRequest;
 import com.android.net.module.util.SharedLog;
 import com.android.server.ServiceManagerWrapper;
 import com.android.server.connectivity.ConnectivityResources;
@@ -193,10 +197,12 @@
     private final NetworkProvider mNetworkProvider;
     private final Supplier<IOtDaemon> mOtDaemonSupplier;
     private final ConnectivityManager mConnectivityManager;
+    private final RoutingCoordinatorManager mRoutingCoordinatorManager;
     private final TunInterfaceController mTunIfController;
     private final InfraInterfaceController mInfraIfController;
     private final NsdPublisher mNsdPublisher;
     private final OtDaemonCallbackProxy mOtDaemonCallbackProxy = new OtDaemonCallbackProxy();
+    private final Nat64CidrController mNat64CidrController = new Nat64CidrController();
     private final ConnectivityResources mResources;
     private final Supplier<String> mCountryCodeSupplier;
     private final Map<IConfigurationReceiver, IBinder.DeathRecipient> mConfigurationReceivers =
@@ -229,6 +235,7 @@
             NetworkProvider networkProvider,
             Supplier<IOtDaemon> otDaemonSupplier,
             ConnectivityManager connectivityManager,
+            RoutingCoordinatorManager routingCoordinatorManager,
             TunInterfaceController tunIfController,
             InfraInterfaceController infraIfController,
             ThreadPersistentSettings persistentSettings,
@@ -242,6 +249,7 @@
         mNetworkProvider = networkProvider;
         mOtDaemonSupplier = otDaemonSupplier;
         mConnectivityManager = connectivityManager;
+        mRoutingCoordinatorManager = routingCoordinatorManager;
         mTunIfController = tunIfController;
         mInfraIfController = infraIfController;
         mUpstreamNetworkRequest = newUpstreamNetworkRequest();
@@ -266,13 +274,19 @@
         NetworkProvider networkProvider =
                 new NetworkProvider(context, handlerThread.getLooper(), "ThreadNetworkProvider");
         Map<Network, LinkProperties> networkToLinkProperties = new HashMap<>();
+        final ConnectivityManager connectivityManager =
+                context.getSystemService(ConnectivityManager.class);
+        final RoutingCoordinatorManager routingCoordinatorManager =
+                new RoutingCoordinatorManager(
+                        context, connectivityManager.getRoutingCoordinatorService());
 
         return new ThreadNetworkControllerService(
                 context,
                 handler,
                 networkProvider,
                 () -> IOtDaemon.Stub.asInterface(ServiceManagerWrapper.waitForService("ot_daemon")),
-                context.getSystemService(ConnectivityManager.class),
+                connectivityManager,
+                routingCoordinatorManager,
                 new TunInterfaceController(TUN_IF_NAME),
                 new InfraInterfaceController(),
                 persistentSettings,
@@ -351,6 +365,7 @@
                 mCountryCodeSupplier.get());
         otDaemon.asBinder().linkToDeath(() -> mHandler.post(this::onOtDaemonDied), 0);
         mOtDaemon = otDaemon;
+        mHandler.post(mNat64CidrController::maybeUpdateNat64Cidr);
         return mOtDaemon;
     }
 
@@ -589,6 +604,7 @@
         } catch (RemoteException | ThreadNetworkException e) {
             LOG.e("otDaemon.setConfiguration failed. Config: " + configuration, e);
         }
+        mNat64CidrController.maybeUpdateNat64Cidr();
     }
 
     private static OtDaemonConfiguration newOtDaemonConfig(
@@ -833,7 +849,7 @@
                 mHandler.getLooper(),
                 LOG.getTag(),
                 netCaps,
-                mTunIfController.getLinkProperties(),
+                getTunIfLinkProperties(),
                 newLocalNetworkConfig(),
                 score,
                 new NetworkAgentConfig.Builder().build(),
@@ -1391,9 +1407,7 @@
 
         // The OT daemon can send link property updates before the networkAgent is
         // registered
-        if (mNetworkAgent != null) {
-            mNetworkAgent.sendLinkProperties(mTunIfController.getLinkProperties());
-        }
+        maybeSendLinkProperties();
     }
 
     private void handlePrefixChanged(List<OnMeshPrefixConfig> onMeshPrefixConfigList) {
@@ -1403,9 +1417,18 @@
 
         // The OT daemon can send link property updates before the networkAgent is
         // registered
-        if (mNetworkAgent != null) {
-            mNetworkAgent.sendLinkProperties(mTunIfController.getLinkProperties());
+        maybeSendLinkProperties();
+    }
+
+    private void maybeSendLinkProperties() {
+        if (mNetworkAgent == null) {
+            return;
         }
+        mNetworkAgent.sendLinkProperties(getTunIfLinkProperties());
+    }
+
+    private LinkProperties getTunIfLinkProperties() {
+        return mTunIfController.getLinkPropertiesWithNat64Cidr(mNat64CidrController.mNat64Cidr);
     }
 
     @RequiresPermission(
@@ -1851,4 +1874,64 @@
             mHandler.post(() -> handlePrefixChanged(onMeshPrefixConfigList));
         }
     }
+
+    private final class Nat64CidrController extends IIpv4PrefixRequest.Stub {
+        private static final int RETRY_DELAY_ON_FAILURE_MILLIS = 600_000; // 10 minutes
+
+        @Nullable private LinkAddress mNat64Cidr;
+
+        @Override
+        public void onIpv4PrefixConflict(IpPrefix prefix) {
+            mHandler.post(() -> onIpv4PrefixConflictInternal(prefix));
+        }
+
+        private void onIpv4PrefixConflictInternal(IpPrefix prefix) {
+            checkOnHandlerThread();
+
+            LOG.i("Conflict on NAT64 CIDR: " + prefix);
+            maybeReleaseNat64Cidr();
+            maybeUpdateNat64Cidr();
+        }
+
+        public void maybeUpdateNat64Cidr() {
+            checkOnHandlerThread();
+
+            if (mPersistentSettings.getConfiguration().isNat64Enabled()) {
+                maybeRequestNat64Cidr();
+            } else {
+                maybeReleaseNat64Cidr();
+            }
+            try {
+                getOtDaemon()
+                        .setNat64Cidr(
+                                mNat64Cidr == null ? null : mNat64Cidr.toString(),
+                                new LoggingOtStatusReceiver("setNat64Cidr"));
+            } catch (RemoteException | ThreadNetworkException e) {
+                LOG.e("Failed to set NAT64 CIDR at otd-daemon", e);
+            }
+            maybeSendLinkProperties();
+        }
+
+        private void maybeRequestNat64Cidr() {
+            if (mNat64Cidr != null) {
+                return;
+            }
+            final LinkAddress downstreamAddress =
+                    mRoutingCoordinatorManager.requestDownstreamAddress(this);
+            if (downstreamAddress == null) {
+                mHandler.postDelayed(() -> maybeUpdateNat64Cidr(), RETRY_DELAY_ON_FAILURE_MILLIS);
+            }
+            mNat64Cidr = downstreamAddress;
+            LOG.i("Allocated NAT64 CIDR: " + mNat64Cidr);
+        }
+
+        private void maybeReleaseNat64Cidr() {
+            if (mNat64Cidr == null) {
+                return;
+            }
+            LOG.i("Released NAT64 CIDR: " + mNat64Cidr);
+            mNat64Cidr = null;
+            mRoutingCoordinatorManager.releaseDownstream(this);
+        }
+    }
 }
diff --git a/thread/service/java/com/android/server/thread/TunInterfaceController.java b/thread/service/java/com/android/server/thread/TunInterfaceController.java
index 3bff9c6..520a434 100644
--- a/thread/service/java/com/android/server/thread/TunInterfaceController.java
+++ b/thread/service/java/com/android/server/thread/TunInterfaceController.java
@@ -92,10 +92,21 @@
     }
 
     /** Returns link properties of the Thread TUN interface. */
-    public LinkProperties getLinkProperties() {
+    private LinkProperties getLinkProperties() {
         return new LinkProperties(mLinkProperties);
     }
 
+    /** Returns link properties of the Thread TUN interface with the given NAT64 CIDR. */
+    // TODO: manage the NAT64 CIDR in the TunInterfaceController
+    public LinkProperties getLinkPropertiesWithNat64Cidr(@Nullable LinkAddress nat64Cidr) {
+        final LinkProperties lp = getLinkProperties();
+        if (nat64Cidr != null) {
+            lp.addLinkAddress(nat64Cidr);
+            lp.addRoute(getRouteForAddress(nat64Cidr));
+        }
+        return lp;
+    }
+
     /**
      * Creates the tunnel interface.
      *
@@ -148,6 +159,9 @@
 
     /** Adds a new address to the interface. */
     public void addAddress(LinkAddress address) {
+        if (!(address.getAddress() instanceof Inet6Address)) {
+            return;
+        }
         LOG.v("Adding address " + address + " with flags: " + address.getFlags());
 
         long preferredLifetimeSeconds;
@@ -172,7 +186,7 @@
                             (address.getExpirationTime() - SystemClock.elapsedRealtime()) / 1000L,
                             0L);
         }
-
+        // Only apply to Ipv6 address
         if (!NetlinkUtils.sendRtmNewAddressRequest(
                 Os.if_nametoindex(mIfName),
                 address.getAddress(),
@@ -190,6 +204,9 @@
 
     /** Removes an address from the interface. */
     public void removeAddress(LinkAddress address) {
+        if (!(address.getAddress() instanceof Inet6Address)) {
+            return;
+        }
         LOG.v("Removing address " + address);
 
         // Intentionally update the mLinkProperties before send netlink message because the
@@ -197,6 +214,7 @@
         // when the netlink request below fails
         mLinkProperties.removeLinkAddress(address);
         mLinkProperties.removeRoute(getRouteForAddress(address));
+        // Only apply to Ipv6 address
         if (!NetlinkUtils.sendRtmDelAddressRequest(
                 Os.if_nametoindex(mIfName),
                 (Inet6Address) address.getAddress(),
diff --git a/thread/tests/integration/src/android/net/thread/BorderRoutingTest.java b/thread/tests/integration/src/android/net/thread/BorderRoutingTest.java
index f8e92f0..f6dd6b9 100644
--- a/thread/tests/integration/src/android/net/thread/BorderRoutingTest.java
+++ b/thread/tests/integration/src/android/net/thread/BorderRoutingTest.java
@@ -19,6 +19,7 @@
 import static android.Manifest.permission.MANAGE_TEST_NETWORKS;
 import static android.net.InetAddresses.parseNumericAddress;
 import static android.net.thread.utils.IntegrationTestUtils.DEFAULT_DATASET;
+import static android.net.thread.utils.IntegrationTestUtils.buildIcmpv4EchoReply;
 import static android.net.thread.utils.IntegrationTestUtils.getIpv6LinkAddresses;
 import static android.net.thread.utils.IntegrationTestUtils.isExpectedIcmpv4Packet;
 import static android.net.thread.utils.IntegrationTestUtils.isExpectedIcmpv6Packet;
@@ -77,9 +78,11 @@
 import org.junit.Test;
 import org.junit.runner.RunWith;
 
+import java.io.IOException;
 import java.net.Inet4Address;
 import java.net.Inet6Address;
 import java.net.InetAddress;
+import java.nio.ByteBuffer;
 import java.time.Duration;
 import java.util.ArrayList;
 import java.util.List;
@@ -101,7 +104,6 @@
             (Inet6Address) parseNumericAddress("ff03::1234");
     private static final Inet4Address IPV4_SERVER_ADDR =
             (Inet4Address) parseNumericAddress("8.8.8.8");
-    private static final String NAT64_CIDR = "192.168.255.0/24";
     private static final IpPrefix DHCP6_PD_PREFIX = new IpPrefix("2001:db8::/64");
     private static final IpPrefix AIL_NAT64_PREFIX = new IpPrefix("2001:db8:1234::/96");
     private static final Inet6Address AIL_NAT64_SYNTHESIZED_SERVER_ADDR =
@@ -647,16 +649,27 @@
     }
 
     @Test
-    public void nat64_threadDevicePingIpv4InfraDevice_outboundPacketIsForwarded() throws Exception {
+    public void nat64_threadDevicePingIpv4InfraDevice_outboundPacketIsForwardedAndReplyIsReceived()
+            throws Exception {
         FullThreadDevice ftd = mFtds.get(0);
         joinNetworkAndWaitForOmr(ftd, DEFAULT_DATASET);
-        mOtCtl.setNat64Cidr(NAT64_CIDR);
         mController.setNat64EnabledAndWait(true);
         waitFor(() -> mOtCtl.hasNat64PrefixInNetdata(), UPDATE_NAT64_PREFIX_TIMEOUT);
+        Thread echoReplyThread = new Thread(() -> respondToEchoRequestOnce(IPV4_SERVER_ADDR));
+        echoReplyThread.start();
 
-        ftd.ping(IPV4_SERVER_ADDR);
+        assertThat(ftd.ping(IPV4_SERVER_ADDR, 1 /* count */)).isEqualTo(1);
 
-        assertNotNull(pollForIcmpPacketOnInfraNetwork(ICMP_ECHO, null, IPV4_SERVER_ADDR));
+        echoReplyThread.join();
+    }
+
+    private void respondToEchoRequestOnce(Inet4Address dstAddress) {
+        byte[] echoRequest = pollForIcmpPacketOnInfraNetwork(ICMP_ECHO, null, dstAddress);
+        assertNotNull(echoRequest);
+        try {
+            mInfraNetworkReader.sendResponse(buildIcmpv4EchoReply(ByteBuffer.wrap(echoRequest)));
+        } catch (IOException ignored) {
+        }
     }
 
     @Test
diff --git a/thread/tests/integration/src/android/net/thread/utils/IntegrationTestUtils.kt b/thread/tests/integration/src/android/net/thread/utils/IntegrationTestUtils.kt
index d903636..dc2a9c9 100644
--- a/thread/tests/integration/src/android/net/thread/utils/IntegrationTestUtils.kt
+++ b/thread/tests/integration/src/android/net/thread/utils/IntegrationTestUtils.kt
@@ -38,9 +38,15 @@
 import android.os.Handler
 import android.os.SystemClock
 import android.system.OsConstants
+import android.system.OsConstants.IPPROTO_ICMP
 import androidx.test.core.app.ApplicationProvider
 import com.android.compatibility.common.util.SystemUtil.runShellCommandOrThrow
+import com.android.net.module.util.IpUtils
 import com.android.net.module.util.NetworkStackConstants
+import com.android.net.module.util.NetworkStackConstants.ICMP_CHECKSUM_OFFSET
+import com.android.net.module.util.NetworkStackConstants.IPV4_CHECKSUM_OFFSET
+import com.android.net.module.util.NetworkStackConstants.IPV4_HEADER_MIN_LEN
+import com.android.net.module.util.NetworkStackConstants.IPV4_LENGTH_OFFSET
 import com.android.net.module.util.Struct
 import com.android.net.module.util.structs.Icmpv4Header
 import com.android.net.module.util.structs.Icmpv6Header
@@ -307,6 +313,73 @@
         return null
     }
 
+    /** Builds an ICMPv4 Echo Reply packet to respond to the given ICMPv4 Echo Request packet. */
+    @JvmStatic
+    fun buildIcmpv4EchoReply(request: ByteBuffer): ByteBuffer? {
+        val requestIpv4Header = Struct.parse(Ipv4Header::class.java, request) ?: return null
+        val requestIcmpv4Header = Struct.parse(Icmpv4Header::class.java, request) ?: return null
+
+        val id = request.getShort()
+        val seq = request.getShort()
+
+        val payload = ByteBuffer.allocate(4 + request.limit() - request.position())
+        payload.putShort(id)
+        payload.putShort(seq)
+        payload.put(request)
+        payload.rewind()
+
+        val ipv4HeaderLen = Struct.getSize(Ipv4Header::class.java)
+        val Icmpv4HeaderLen = Struct.getSize(Icmpv4Header::class.java)
+        val payloadLen = payload.limit();
+
+        val reply = ByteBuffer.allocate(ipv4HeaderLen + Icmpv4HeaderLen + payloadLen)
+
+        // IPv4 header
+        val replyIpv4Header = Ipv4Header(
+            0 /* TYPE OF SERVICE */,
+            0.toShort().toInt()/* totalLength, calculate later */,
+            requestIpv4Header.id,
+            requestIpv4Header.flagsAndFragmentOffset,
+            0x40 /* ttl */,
+            IPPROTO_ICMP.toByte(),
+            0.toShort()/* checksum, calculate later */,
+            requestIpv4Header.dstIp /* srcIp */,
+            requestIpv4Header.srcIp /* dstIp */
+        )
+        replyIpv4Header.writeToByteBuffer(reply)
+
+        // ICMPv4 header
+        val replyIcmpv4Header = Icmpv4Header(
+            0 /* type, ICMP_ECHOREPLY */,
+            requestIcmpv4Header.code,
+            0.toShort() /* checksum, calculate later */
+        )
+        replyIcmpv4Header.writeToByteBuffer(reply)
+
+        // Payload
+        reply.put(payload)
+        reply.flip()
+
+        // Populate the IPv4 totalLength field.
+        reply.putShort(
+            IPV4_LENGTH_OFFSET, (ipv4HeaderLen + Icmpv4HeaderLen + payloadLen).toShort()
+        )
+
+        // Populate the IPv4 header checksum field.
+        reply.putShort(
+            IPV4_CHECKSUM_OFFSET, IpUtils.ipChecksum(reply, 0 /* headerOffset */)
+        )
+
+        // Populate the ICMP checksum field.
+        reply.putShort(
+            IPV4_HEADER_MIN_LEN + ICMP_CHECKSUM_OFFSET, IpUtils.icmpChecksum(
+                reply, IPV4_HEADER_MIN_LEN, Icmpv4HeaderLen + payloadLen
+            )
+        )
+
+        return reply
+    }
+
     /** Returns the Prefix Information Options (PIO) extracted from an ICMPv6 RA message.  */
     @JvmStatic
     fun getRaPios(raMsg: ByteArray?): List<PrefixInformationOption> {
diff --git a/thread/tests/unit/src/com/android/server/thread/ThreadNetworkControllerServiceTest.java b/thread/tests/unit/src/com/android/server/thread/ThreadNetworkControllerServiceTest.java
index 7ac404f..e188491 100644
--- a/thread/tests/unit/src/com/android/server/thread/ThreadNetworkControllerServiceTest.java
+++ b/thread/tests/unit/src/com/android/server/thread/ThreadNetworkControllerServiceTest.java
@@ -44,6 +44,8 @@
 import static org.mockito.ArgumentMatchers.anyString;
 import static org.mockito.ArgumentMatchers.argThat;
 import static org.mockito.ArgumentMatchers.eq;
+import static org.mockito.ArgumentMatchers.isNotNull;
+import static org.mockito.ArgumentMatchers.isNull;
 import static org.mockito.Mockito.any;
 import static org.mockito.Mockito.atLeastOnce;
 import static org.mockito.Mockito.clearInvocations;
@@ -64,6 +66,7 @@
 import android.content.Intent;
 import android.content.res.Resources;
 import android.net.ConnectivityManager;
+import android.net.LinkAddress;
 import android.net.LinkProperties;
 import android.net.Network;
 import android.net.NetworkAgent;
@@ -91,9 +94,12 @@
 
 import com.android.connectivity.resources.R;
 import com.android.dx.mockito.inline.extended.ExtendedMockito;
+import com.android.net.module.util.RoutingCoordinatorManager;
 import com.android.server.connectivity.ConnectivityResources;
 import com.android.server.thread.openthread.DnsTxtAttribute;
+import com.android.server.thread.openthread.IOtStatusReceiver;
 import com.android.server.thread.openthread.MeshcopTxtAttributes;
+import com.android.server.thread.openthread.OtDaemonConfiguration;
 import com.android.server.thread.openthread.testing.FakeOtDaemon;
 
 import org.junit.Before;
@@ -164,8 +170,10 @@
     private static final byte[] TEST_VENDOR_OUI_BYTES = new byte[] {(byte) 0xAC, (byte) 0xDE, 0x48};
     private static final String TEST_VENDOR_NAME = "test vendor";
     private static final String TEST_MODEL_NAME = "test model";
+    private static final LinkAddress TEST_NAT64_CIDR = new LinkAddress("192.168.255.0/24");
 
     @Mock private ConnectivityManager mMockConnectivityManager;
+    @Mock private RoutingCoordinatorManager mMockRoutingCoordinatorManager;
     @Mock private NetworkAgent mMockNetworkAgent;
     @Mock private TunInterfaceController mMockTunIfController;
     @Mock private ParcelFileDescriptor mMockTunFd;
@@ -208,7 +216,10 @@
         NetworkProvider networkProvider =
                 new NetworkProvider(mContext, mTestLooper.getLooper(), "ThreadNetworkProvider");
 
-        mFakeOtDaemon = new FakeOtDaemon(handler);
+        when(mMockRoutingCoordinatorManager.requestDownstreamAddress(any()))
+                .thenReturn(TEST_NAT64_CIDR);
+
+        mFakeOtDaemon = spy(new FakeOtDaemon(handler));
         when(mMockTunIfController.getTunFd()).thenReturn(mMockTunFd);
 
         when(mMockUserManager.hasUserRestriction(eq(DISALLOW_THREAD_NETWORK))).thenReturn(false);
@@ -235,6 +246,7 @@
                         networkProvider,
                         () -> mFakeOtDaemon,
                         mMockConnectivityManager,
+                        mMockRoutingCoordinatorManager,
                         mMockTunIfController,
                         mMockInfraIfController,
                         mPersistentSettings,
@@ -281,6 +293,37 @@
     }
 
     @Test
+    public void initialize_nat64Disabled_doesNotRequestNat64CidrAndConfiguresOtDaemon()
+            throws Exception {
+        ThreadConfiguration config =
+                new ThreadConfiguration.Builder().setNat64Enabled(false).build();
+        mPersistentSettings.putConfiguration(config);
+        mService.initialize();
+        mTestLooper.dispatchAll();
+
+        verify(mMockRoutingCoordinatorManager, never()).requestDownstreamAddress(any());
+        verify(mFakeOtDaemon, times(1)).setNat64Cidr(isNull(), any());
+        verify(mFakeOtDaemon, never()).setNat64Cidr(isNotNull(), any());
+    }
+
+    @Test
+    public void initialize_nat64Enabled_requestsNat64CidrAndConfiguresAtOtDaemon()
+            throws Exception {
+        ThreadConfiguration config =
+                new ThreadConfiguration.Builder().setNat64Enabled(true).build();
+        mPersistentSettings.putConfiguration(config);
+        mService.initialize();
+        mTestLooper.dispatchAll();
+
+        verify(mMockRoutingCoordinatorManager, times(1)).requestDownstreamAddress(any());
+        verify(mFakeOtDaemon, times(1))
+                .setConfiguration(
+                        new OtDaemonConfiguration.Builder().setNat64Enabled(true).build(),
+                        null /* receiver */);
+        verify(mFakeOtDaemon, times(1)).setNat64Cidr(eq(TEST_NAT64_CIDR.toString()), any());
+    }
+
+    @Test
     public void getMeshcopTxtAttributes_emptyVendorName_accepted() {
         when(mResources.getString(eq(R.string.config_thread_vendor_name))).thenReturn("");
 
@@ -758,6 +801,71 @@
     }
 
     @Test
+    public void setConfiguration_enablesNat64_requestsNat64CidrAndConfiguresOtdaemon()
+            throws Exception {
+        mService.initialize();
+        mTestLooper.dispatchAll();
+        clearInvocations(mMockRoutingCoordinatorManager, mFakeOtDaemon);
+
+        final IOperationReceiver mockReceiver = mock(IOperationReceiver.class);
+        mService.setConfiguration(
+                new ThreadConfiguration.Builder().setNat64Enabled(true).build(), mockReceiver);
+        mTestLooper.dispatchAll();
+
+        verify(mockReceiver, times(1)).onSuccess();
+        verify(mMockRoutingCoordinatorManager, times(1)).requestDownstreamAddress(any());
+        verify(mFakeOtDaemon, times(1))
+                .setConfiguration(
+                        eq(new OtDaemonConfiguration.Builder().setNat64Enabled(true).build()),
+                        any(IOtStatusReceiver.class));
+        verify(mFakeOtDaemon, times(1))
+                .setNat64Cidr(eq(TEST_NAT64_CIDR.toString()), any(IOtStatusReceiver.class));
+    }
+
+    @Test
+    public void setConfiguration_enablesNat64_otDaemonRemoteFailure_serviceDoesNotCrash()
+            throws Exception {
+        mService.initialize();
+        mTestLooper.dispatchAll();
+        clearInvocations(mMockRoutingCoordinatorManager, mFakeOtDaemon);
+        mFakeOtDaemon.setSetNat64CidrException(
+                new RemoteException("ot-daemon setNat64Cidr() throws"));
+
+        final IOperationReceiver mockReceiver = mock(IOperationReceiver.class);
+        mService.setConfiguration(
+                new ThreadConfiguration.Builder().setNat64Enabled(true).build(), mockReceiver);
+        mTestLooper.dispatchAll();
+
+        verify(mFakeOtDaemon, times(1))
+                .setNat64Cidr(eq(TEST_NAT64_CIDR.toString()), any(IOtStatusReceiver.class));
+    }
+
+    @Test
+    public void setConfiguration_disablesNat64_releasesNat64CidrAndConfiguresOtdaemon()
+            throws Exception {
+        mPersistentSettings.putConfiguration(
+                new ThreadConfiguration.Builder().setNat64Enabled(true).build());
+        mService.initialize();
+        mTestLooper.dispatchAll();
+        clearInvocations(mMockRoutingCoordinatorManager, mFakeOtDaemon);
+
+        final IOperationReceiver mockReceiver = mock(IOperationReceiver.class);
+        mService.setConfiguration(
+                new ThreadConfiguration.Builder().setNat64Enabled(false).build(), mockReceiver);
+        mTestLooper.dispatchAll();
+
+        verify(mockReceiver, times(1)).onSuccess();
+        verify(mMockRoutingCoordinatorManager, times(1)).releaseDownstream(any());
+        verify(mMockRoutingCoordinatorManager, never()).requestDownstreamAddress(any());
+        verify(mFakeOtDaemon, times(1))
+                .setConfiguration(
+                        eq(new OtDaemonConfiguration.Builder().setNat64Enabled(false).build()),
+                        any(IOtStatusReceiver.class));
+        verify(mFakeOtDaemon, times(1)).setNat64Cidr(isNull(), any(IOtStatusReceiver.class));
+        verify(mFakeOtDaemon, never()).setNat64Cidr(isNotNull(), any(IOtStatusReceiver.class));
+    }
+
+    @Test
     public void initialize_upstreamNetworkRequestHasCertainTransportTypesAndCapabilities() {
         mService.initialize();
         mTestLooper.dispatchAll();