diff --git a/Tethering/Android.bp b/Tethering/Android.bp
index 0cfd884..27297c4 100644
--- a/Tethering/Android.bp
+++ b/Tethering/Android.bp
@@ -25,7 +25,7 @@
     ],
     static_libs: [
         "androidx.annotation_annotation",
-        "netd_aidl_interface-unstable-java",
+        "netd_aidl_interface-V3-java",
         "netlink-client",
         "networkstack-aidl-interfaces-unstable-java",
         "android.hardware.tetheroffload.config-V1.0-java",
diff --git a/Tethering/src/android/net/ip/IpServer.java b/Tethering/src/android/net/ip/IpServer.java
index 82b17ac..1dac5b7 100644
--- a/Tethering/src/android/net/ip/IpServer.java
+++ b/Tethering/src/android/net/ip/IpServer.java
@@ -34,6 +34,7 @@
 import android.net.LinkProperties;
 import android.net.MacAddress;
 import android.net.RouteInfo;
+import android.net.TetherOffloadRuleParcel;
 import android.net.TetheredClient;
 import android.net.TetheringManager;
 import android.net.TetheringRequestParcel;
@@ -41,7 +42,7 @@
 import android.net.dhcp.DhcpServerCallbacks;
 import android.net.dhcp.DhcpServingParamsParcel;
 import android.net.dhcp.DhcpServingParamsParcelExt;
-import android.net.dhcp.IDhcpLeaseCallbacks;
+import android.net.dhcp.IDhcpEventCallbacks;
 import android.net.dhcp.IDhcpServer;
 import android.net.ip.IpNeighborMonitor.NeighborEvent;
 import android.net.ip.RouterAdvertisementDaemon.RaParams;
@@ -280,6 +281,19 @@
             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.
+        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;
+        }
     }
     private final LinkedHashMap<Inet6Address, Ipv6ForwardingRule> mIpv6ForwardingRules =
             new LinkedHashMap<>();
@@ -449,7 +463,7 @@
         }
     }
 
-    private class DhcpLeaseCallback extends IDhcpLeaseCallbacks.Stub {
+    private class DhcpLeaseCallback extends IDhcpEventCallbacks.Stub {
         @Override
         public void onLeasesChanged(List<DhcpLeaseParcelable> leaseParcelables) {
             final ArrayList<TetheredClient> leases = new ArrayList<>();
@@ -483,6 +497,11 @@
         }
 
         @Override
+        public void onNewPrefixRequest(IpPrefix currentPrefix) {
+            //TODO: add specific implementation.
+        }
+
+        @Override
         public int getInterfaceVersion() {
             return this.VERSION;
         }
@@ -824,9 +843,7 @@
 
     private void addIpv6ForwardingRule(Ipv6ForwardingRule rule) {
         try {
-            mNetd.tetherRuleAddDownstreamIpv6(mInterfaceParams.index, rule.upstreamIfindex,
-                    rule.address.getAddress(),  mInterfaceParams.macAddr.toByteArray(),
-                    rule.dstMac.toByteArray());
+            mNetd.tetherOffloadRuleAdd(rule.toTetherOffloadRuleParcel());
             mIpv6ForwardingRules.put(rule.address, rule);
         } catch (RemoteException | ServiceSpecificException e) {
             mLog.e("Could not add IPv6 downstream rule: ", e);
@@ -835,7 +852,7 @@
 
     private void removeIpv6ForwardingRule(Ipv6ForwardingRule rule, boolean removeFromMap) {
         try {
-            mNetd.tetherRuleRemoveDownstreamIpv6(rule.upstreamIfindex, rule.address.getAddress());
+            mNetd.tetherOffloadRuleRemove(rule.toTetherOffloadRuleParcel());
             if (removeFromMap) {
                 mIpv6ForwardingRules.remove(rule.address);
             }
diff --git a/Tethering/tests/integration/Android.bp b/Tethering/tests/integration/Android.bp
index 1a1c30d..620261b 100644
--- a/Tethering/tests/integration/Android.bp
+++ b/Tethering/tests/integration/Android.bp
@@ -39,4 +39,9 @@
         "android.test.base",
         "android.test.mock",
     ],
+    jni_libs: [
+        // For mockito extended
+        "libdexmakerjvmtiagent",
+        "libstaticjvmtiagent",
+    ],
 }
diff --git a/Tethering/tests/integration/src/android/net/EthernetTetheringTest.java b/Tethering/tests/integration/src/android/net/EthernetTetheringTest.java
index dbd68ef..b02bb23 100644
--- a/Tethering/tests/integration/src/android/net/EthernetTetheringTest.java
+++ b/Tethering/tests/integration/src/android/net/EthernetTetheringTest.java
@@ -205,7 +205,7 @@
                 requestWithStaticIpv4(localAddr, clientAddr));
 
         mTetheringEventCallback.awaitInterfaceTethered();
-        assertInterfaceHasIpAddress(iface, clientAddr);
+        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();
diff --git a/Tethering/tests/unit/AndroidManifest.xml b/Tethering/tests/unit/AndroidManifest.xml
index 530bc07..4ff1d37 100644
--- a/Tethering/tests/unit/AndroidManifest.xml
+++ b/Tethering/tests/unit/AndroidManifest.xml
@@ -20,7 +20,16 @@
 
     <application android:debuggable="true">
         <uses-library android:name="android.test.runner" />
+        <service
+            android:name="com.android.server.connectivity.tethering.MockTetheringService"
+            android:permission="android.permission.TETHER_PRIVILEGED"
+            android:exported="true">
+            <intent-filter>
+                <action android:name="com.android.server.connectivity.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">
diff --git a/Tethering/tests/unit/src/android/net/ip/IpServerTest.java b/Tethering/tests/unit/src/android/net/ip/IpServerTest.java
index 3106e0e..fdfdae8 100644
--- a/Tethering/tests/unit/src/android/net/ip/IpServerTest.java
+++ b/Tethering/tests/unit/src/android/net/ip/IpServerTest.java
@@ -43,7 +43,6 @@
 import static org.junit.Assert.fail;
 import static org.mockito.ArgumentMatchers.argThat;
 import static org.mockito.Matchers.any;
-import static org.mockito.Matchers.anyInt;
 import static org.mockito.Matchers.anyString;
 import static org.mockito.Matchers.eq;
 import static org.mockito.Mockito.doAnswer;
@@ -66,6 +65,7 @@
 import android.net.LinkProperties;
 import android.net.MacAddress;
 import android.net.RouteInfo;
+import android.net.TetherOffloadRuleParcel;
 import android.net.dhcp.DhcpServingParamsParcel;
 import android.net.dhcp.IDhcpServer;
 import android.net.dhcp.IDhcpServerCallbacks;
@@ -85,6 +85,7 @@
 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;
@@ -92,6 +93,7 @@
 
 import java.net.Inet4Address;
 import java.net.InetAddress;
+import java.util.Arrays;
 
 @RunWith(AndroidJUnit4.class)
 @SmallTest
@@ -514,6 +516,65 @@
         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.
+     *
+     * 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);
+        }
+    }
+
+    private TetherOffloadRuleParcel matches(
+            int upstreamIfindex, InetAddress dst, MacAddress dstMac) {
+        return argThat(new TetherOffloadRuleParcelMatcher(upstreamIfindex, dst, dstMac));
+    }
+
     @Test
     public void addRemoveipv6ForwardingRules() throws Exception {
         initTetheredStateMachine(TETHERING_WIFI, UPSTREAM_IFACE, false /* usingLegacyDhcp */);
@@ -537,13 +598,11 @@
 
         // Events on this interface are received and sent to netd.
         recvNewNeigh(myIfindex, neighA, NUD_REACHABLE, macA);
-        verify(mNetd).tetherRuleAddDownstreamIpv6(eq(myIfindex), eq(UPSTREAM_IFINDEX),
-                eq(neighA.getAddress()), eq(myMac.toByteArray()), eq(macA.toByteArray()));
+        verify(mNetd).tetherOffloadRuleAdd(matches(UPSTREAM_IFINDEX, neighA, macA));
         reset(mNetd);
 
         recvNewNeigh(myIfindex, neighB, NUD_REACHABLE, macB);
-        verify(mNetd).tetherRuleAddDownstreamIpv6(eq(myIfindex), eq(UPSTREAM_IFINDEX),
-                eq(neighB.getAddress()), eq(myMac.toByteArray()), eq(macB.toByteArray()));
+        verify(mNetd).tetherOffloadRuleAdd(matches(UPSTREAM_IFINDEX, neighB, macB));
         reset(mNetd);
 
         // Link-local and multicast neighbors are ignored.
@@ -554,12 +613,12 @@
 
         // A neighbor that is no longer valid causes the rule to be removed.
         recvNewNeigh(myIfindex, neighA, NUD_FAILED, macA);
-        verify(mNetd).tetherRuleRemoveDownstreamIpv6(eq(UPSTREAM_IFINDEX), eq(neighA.getAddress()));
+        verify(mNetd).tetherOffloadRuleRemove(matches(UPSTREAM_IFINDEX, neighA, macA));
         reset(mNetd);
 
         // A neighbor that is deleted causes the rule to be removed.
         recvDelNeigh(myIfindex, neighB, NUD_STALE, macB);
-        verify(mNetd).tetherRuleRemoveDownstreamIpv6(eq(UPSTREAM_IFINDEX), eq(neighB.getAddress()));
+        verify(mNetd).tetherOffloadRuleRemove(matches(UPSTREAM_IFINDEX, neighB, macB));
         reset(mNetd);
 
         // Upstream changes result in deleting and re-adding the rules.
@@ -571,22 +630,16 @@
         LinkProperties lp = new LinkProperties();
         lp.setInterfaceName(UPSTREAM_IFACE2);
         dispatchTetherConnectionChanged(UPSTREAM_IFACE2, lp);
-        inOrder.verify(mNetd).tetherRuleAddDownstreamIpv6(eq(myIfindex), eq(UPSTREAM_IFINDEX2),
-                eq(neighA.getAddress()), eq(myMac.toByteArray()), eq(macA.toByteArray()));
-        inOrder.verify(mNetd).tetherRuleRemoveDownstreamIpv6(eq(UPSTREAM_IFINDEX),
-                    eq(neighA.getAddress()));
-        inOrder.verify(mNetd).tetherRuleAddDownstreamIpv6(eq(myIfindex), eq(UPSTREAM_IFINDEX2),
-                eq(neighB.getAddress()), eq(myMac.toByteArray()), eq(macB.toByteArray()));
-        inOrder.verify(mNetd).tetherRuleRemoveDownstreamIpv6(eq(UPSTREAM_IFINDEX),
-                eq(neighB.getAddress()));
+        inOrder.verify(mNetd).tetherOffloadRuleAdd(matches(UPSTREAM_IFINDEX2, neighA, macA));
+        inOrder.verify(mNetd).tetherOffloadRuleRemove(matches(UPSTREAM_IFINDEX, neighA, macA));
+        inOrder.verify(mNetd).tetherOffloadRuleAdd(matches(UPSTREAM_IFINDEX2, neighB, macB));
+        inOrder.verify(mNetd).tetherOffloadRuleRemove(matches(UPSTREAM_IFINDEX, neighB, macB));
         reset(mNetd);
 
         // When the upstream is lost, rules are removed.
         dispatchTetherConnectionChanged(null, null);
-        verify(mNetd).tetherRuleRemoveDownstreamIpv6(eq(UPSTREAM_IFINDEX2),
-                eq(neighA.getAddress()));
-        verify(mNetd).tetherRuleRemoveDownstreamIpv6(eq(UPSTREAM_IFINDEX2),
-                eq(neighB.getAddress()));
+        verify(mNetd).tetherOffloadRuleRemove(matches(UPSTREAM_IFINDEX2, neighA, macA));
+        verify(mNetd).tetherOffloadRuleRemove(matches(UPSTREAM_IFINDEX2, neighB, macB));
         reset(mNetd);
 
         // If the upstream is IPv4-only, no rules are added.
@@ -599,31 +652,27 @@
         lp.setInterfaceName(UPSTREAM_IFACE);
         dispatchTetherConnectionChanged(UPSTREAM_IFACE, lp);
         recvNewNeigh(myIfindex, neighB, NUD_REACHABLE, macB);
-        verify(mNetd).tetherRuleAddDownstreamIpv6(eq(myIfindex), eq(UPSTREAM_IFINDEX),
-                eq(neighB.getAddress()), eq(myMac.toByteArray()), eq(macB.toByteArray()));
-        verify(mNetd, never()).tetherRuleAddDownstreamIpv6(anyInt(), anyInt(),
-                eq(neighA.getAddress()), any(), any());
+        verify(mNetd).tetherOffloadRuleAdd(matches(UPSTREAM_IFINDEX, neighB, macB));
+        verify(mNetd, never()).tetherOffloadRuleAdd(matches(UPSTREAM_IFINDEX, neighA, macA));
 
         // If upstream IPv6 connectivity is lost, rules are removed.
         reset(mNetd);
         dispatchTetherConnectionChanged(UPSTREAM_IFACE, null);
-        verify(mNetd).tetherRuleRemoveDownstreamIpv6(eq(UPSTREAM_IFINDEX), eq(neighB.getAddress()));
+        verify(mNetd).tetherOffloadRuleRemove(matches(UPSTREAM_IFINDEX, neighB, macB));
 
         // When the interface goes down, rules are removed.
         lp.setInterfaceName(UPSTREAM_IFACE);
         dispatchTetherConnectionChanged(UPSTREAM_IFACE, lp);
         recvNewNeigh(myIfindex, neighA, NUD_REACHABLE, macA);
         recvNewNeigh(myIfindex, neighB, NUD_REACHABLE, macB);
-        verify(mNetd).tetherRuleAddDownstreamIpv6(eq(myIfindex), eq(UPSTREAM_IFINDEX),
-                eq(neighA.getAddress()), eq(myMac.toByteArray()), eq(macA.toByteArray()));
-        verify(mNetd).tetherRuleAddDownstreamIpv6(eq(myIfindex), eq(UPSTREAM_IFINDEX),
-                eq(neighB.getAddress()), eq(myMac.toByteArray()), eq(macB.toByteArray()));
+        verify(mNetd).tetherOffloadRuleAdd(matches(UPSTREAM_IFINDEX, neighA, macA));
+        verify(mNetd).tetherOffloadRuleAdd(matches(UPSTREAM_IFINDEX, neighB, macB));
         reset(mNetd);
 
         mIpServer.stop();
         mLooper.dispatchAll();
-        verify(mNetd).tetherRuleRemoveDownstreamIpv6(eq(UPSTREAM_IFINDEX), eq(neighA.getAddress()));
-        verify(mNetd).tetherRuleRemoveDownstreamIpv6(eq(UPSTREAM_IFINDEX), eq(neighB.getAddress()));
+        verify(mNetd).tetherOffloadRuleRemove(matches(UPSTREAM_IFINDEX, neighA, macA));
+        verify(mNetd).tetherOffloadRuleRemove(matches(UPSTREAM_IFINDEX, neighB, macB));
         reset(mNetd);
     }
 
diff --git a/Tethering/tests/unit/src/com/android/server/connectivity/tethering/IPv6TetheringCoordinatorTest.java b/Tethering/tests/unit/src/com/android/server/connectivity/tethering/IPv6TetheringCoordinatorTest.java
new file mode 100644
index 0000000..9121243
--- /dev/null
+++ b/Tethering/tests/unit/src/com/android/server/connectivity/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.server.connectivity.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(0), 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(0), 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/server/connectivity/tethering/MockTetheringService.java b/Tethering/tests/unit/src/com/android/server/connectivity/tethering/MockTetheringService.java
new file mode 100644
index 0000000..355ece9
--- /dev/null
+++ b/Tethering/tests/unit/src/com/android/server/connectivity/tethering/MockTetheringService.java
@@ -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.
+ */
+package com.android.server.connectivity.tethering;
+
+import static org.mockito.Mockito.mock;
+
+import android.content.Intent;
+import android.net.ITetheringConnector;
+import android.os.Binder;
+import android.os.IBinder;
+
+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;
+    }
+
+    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/server/connectivity/tethering/TetheringServiceTest.java b/Tethering/tests/unit/src/com/android/server/connectivity/tethering/TetheringServiceTest.java
new file mode 100644
index 0000000..d9d3e73
--- /dev/null
+++ b/Tethering/tests/unit/src/com/android/server/connectivity/tethering/TetheringServiceTest.java
@@ -0,0 +1,194 @@
+/*
+ * Copyright (C) 2020 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT 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.tethering;
+
+import static android.net.TetheringManager.TETHERING_WIFI;
+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.verify;
+import static org.mockito.Mockito.verifyNoMoreInteractions;
+import static org.mockito.Mockito.when;
+
+import android.content.Intent;
+import android.net.IIntResultListener;
+import android.net.ITetheringConnector;
+import android.net.ITetheringEventCallback;
+import android.net.TetheringRequestParcel;
+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.server.connectivity.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 = "test_pkg";
+    @Mock private ITetheringEventCallback mITetheringEventCallback;
+    @Rule public ServiceTestRule mServiceTestRule;
+    private Tethering mTethering;
+    private Intent mMockServiceIntent;
+    private ITetheringConnector mTetheringConnector;
+
+    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);
+        }
+    }
+
+    @Before
+    public void setUp() throws Exception {
+        MockitoAnnotations.initMocks(this);
+        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();
+        verify(mTethering).startStateMachineUpdaters();
+        when(mTethering.hasTetherableConfiguration()).thenReturn(true);
+    }
+
+    @After
+    public void tearDown() throws Exception {
+        mServiceTestRule.unbindService();
+    }
+
+    @Test
+    public void testTether() throws Exception {
+        when(mTethering.tether(TEST_IFACE_NAME)).thenReturn(TETHER_ERROR_NO_ERROR);
+        final TestTetheringResult result = new TestTetheringResult();
+        mTetheringConnector.tether(TEST_IFACE_NAME, TEST_CALLER_PKG, result);
+        verify(mTethering).hasTetherableConfiguration();
+        verify(mTethering).tether(TEST_IFACE_NAME);
+        verifyNoMoreInteractions(mTethering);
+        result.assertResult(TETHER_ERROR_NO_ERROR);
+    }
+
+    @Test
+    public void testUntether() throws Exception {
+        when(mTethering.untether(TEST_IFACE_NAME)).thenReturn(TETHER_ERROR_NO_ERROR);
+        final TestTetheringResult result = new TestTetheringResult();
+        mTetheringConnector.untether(TEST_IFACE_NAME, TEST_CALLER_PKG, result);
+        verify(mTethering).hasTetherableConfiguration();
+        verify(mTethering).untether(TEST_IFACE_NAME);
+        verifyNoMoreInteractions(mTethering);
+        result.assertResult(TETHER_ERROR_NO_ERROR);
+    }
+
+    @Test
+    public void testSetUsbTethering() throws Exception {
+        when(mTethering.setUsbTethering(true /* enable */)).thenReturn(TETHER_ERROR_NO_ERROR);
+        final TestTetheringResult result = new TestTetheringResult();
+        mTetheringConnector.setUsbTethering(true /* enable */, TEST_CALLER_PKG, result);
+        verify(mTethering).hasTetherableConfiguration();
+        verify(mTethering).setUsbTethering(true /* enable */);
+        verifyNoMoreInteractions(mTethering);
+        result.assertResult(TETHER_ERROR_NO_ERROR);
+    }
+
+    @Test
+    public void testStartTethering() throws Exception {
+        final TestTetheringResult result = new TestTetheringResult();
+        final TetheringRequestParcel request = new TetheringRequestParcel();
+        request.tetheringType = TETHERING_WIFI;
+        mTetheringConnector.startTethering(request, TEST_CALLER_PKG, result);
+        verify(mTethering).hasTetherableConfiguration();
+        verify(mTethering).startTethering(eq(request), eq(result));
+        verifyNoMoreInteractions(mTethering);
+    }
+
+    @Test
+    public void testStopTethering() throws Exception {
+        final TestTetheringResult result = new TestTetheringResult();
+        mTetheringConnector.stopTethering(TETHERING_WIFI, TEST_CALLER_PKG, result);
+        verify(mTethering).hasTetherableConfiguration();
+        verify(mTethering).stopTethering(TETHERING_WIFI);
+        verifyNoMoreInteractions(mTethering);
+        result.assertResult(TETHER_ERROR_NO_ERROR);
+    }
+
+    @Test
+    public void testRequestLatestTetheringEntitlementResult() throws Exception {
+        final ResultReceiver result = new ResultReceiver(null);
+        mTetheringConnector.requestLatestTetheringEntitlementResult(TETHERING_WIFI, result,
+                true /* showEntitlementUi */, TEST_CALLER_PKG);
+        verify(mTethering).hasTetherableConfiguration();
+        verify(mTethering).requestLatestTetheringEntitlementResult(eq(TETHERING_WIFI),
+                eq(result), eq(true) /* showEntitlementUi */);
+        verifyNoMoreInteractions(mTethering);
+    }
+
+    @Test
+    public void testRegisterTetheringEventCallback() throws Exception {
+        mTetheringConnector.registerTetheringEventCallback(mITetheringEventCallback,
+                TEST_CALLER_PKG);
+        verify(mTethering).registerTetheringEventCallback(eq(mITetheringEventCallback));
+        verifyNoMoreInteractions(mTethering);
+    }
+
+    @Test
+    public void testUnregisterTetheringEventCallback() throws Exception {
+        mTetheringConnector.unregisterTetheringEventCallback(mITetheringEventCallback,
+                TEST_CALLER_PKG);
+        verify(mTethering).unregisterTetheringEventCallback(
+                eq(mITetheringEventCallback));
+        verifyNoMoreInteractions(mTethering);
+    }
+
+    @Test
+    public void testStopAllTethering() throws Exception {
+        final TestTetheringResult result = new TestTetheringResult();
+        mTetheringConnector.stopAllTethering(TEST_CALLER_PKG, result);
+        verify(mTethering).hasTetherableConfiguration();
+        verify(mTethering).untetherAll();
+        verifyNoMoreInteractions(mTethering);
+        result.assertResult(TETHER_ERROR_NO_ERROR);
+    }
+
+    @Test
+    public void testIsTetheringSupported() throws Exception {
+        final TestTetheringResult result = new TestTetheringResult();
+        mTetheringConnector.isTetheringSupported(TEST_CALLER_PKG, result);
+        verify(mTethering).hasTetherableConfiguration();
+        verifyNoMoreInteractions(mTethering);
+        result.assertResult(TETHER_ERROR_NO_ERROR);
+    }
+}
diff --git a/Tethering/tests/unit/src/com/android/server/connectivity/tethering/TetheringTest.java b/Tethering/tests/unit/src/com/android/server/connectivity/tethering/TetheringTest.java
index a418c4a..38059fc 100644
--- a/Tethering/tests/unit/src/com/android/server/connectivity/tethering/TetheringTest.java
+++ b/Tethering/tests/unit/src/com/android/server/connectivity/tethering/TetheringTest.java
@@ -141,7 +141,9 @@
 import com.android.testutils.MiscAssertsKt;
 
 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;
@@ -440,6 +442,18 @@
         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);