diff --git a/OWNERS b/OWNERS
index b2176cc..988af41 100644
--- a/OWNERS
+++ b/OWNERS
@@ -3,3 +3,4 @@
 file:platform/packages/modules/Connectivity:main:/OWNERS_core_networking
 
 per-file **IpSec* = file:platform/frameworks/base:main:/services/core/java/com/android/server/vcn/OWNERS
+per-file **Xfrm* = file:platform/frameworks/base:main:/services/core/java/com/android/server/vcn/OWNERS
diff --git a/Tethering/src/com/android/networkstack/tethering/Tethering.java b/Tethering/src/com/android/networkstack/tethering/Tethering.java
index 996ee11..3277363 100644
--- a/Tethering/src/com/android/networkstack/tethering/Tethering.java
+++ b/Tethering/src/com/android/networkstack/tethering/Tethering.java
@@ -327,8 +327,10 @@
                         return mConfig;
                     }
                 });
-        mUpstreamNetworkMonitor = mDeps.getUpstreamNetworkMonitor(mContext, mTetherMainSM, mLog,
-                TetherMainSM.EVENT_UPSTREAM_CALLBACK);
+        mUpstreamNetworkMonitor = mDeps.getUpstreamNetworkMonitor(mContext, mHandler, mLog,
+                (what, obj) -> {
+                    mTetherMainSM.sendMessage(TetherMainSM.EVENT_UPSTREAM_CALLBACK, what, 0, obj);
+                });
         mForwardedDownstreams = new HashSet<>();
 
         IntentFilter filter = new IntentFilter();
@@ -2879,4 +2881,9 @@
             } catch (RemoteException e) { }
         });
     }
+
+    @VisibleForTesting
+    public TetherMainSM getTetherMainSMForTesting() {
+        return mTetherMainSM;
+    }
 }
diff --git a/Tethering/src/com/android/networkstack/tethering/TetheringDependencies.java b/Tethering/src/com/android/networkstack/tethering/TetheringDependencies.java
index c274165..d02e8e8 100644
--- a/Tethering/src/com/android/networkstack/tethering/TetheringDependencies.java
+++ b/Tethering/src/com/android/networkstack/tethering/TetheringDependencies.java
@@ -35,7 +35,6 @@
 import androidx.annotation.NonNull;
 import androidx.annotation.RequiresApi;
 
-import com.android.internal.util.StateMachine;
 import com.android.modules.utils.build.SdkLevel;
 import com.android.net.module.util.SdkUtil.LateSdk;
 import com.android.net.module.util.SharedLog;
@@ -84,9 +83,9 @@
     /**
      * Get a reference to the UpstreamNetworkMonitor to be used by tethering.
      */
-    public UpstreamNetworkMonitor getUpstreamNetworkMonitor(Context ctx, StateMachine target,
-            SharedLog log, int what) {
-        return new UpstreamNetworkMonitor(ctx, target, log, what);
+    public UpstreamNetworkMonitor getUpstreamNetworkMonitor(Context ctx, Handler h,
+            SharedLog log, UpstreamNetworkMonitor.EventListener listener) {
+        return new UpstreamNetworkMonitor(ctx, h, log, listener);
     }
 
     /**
diff --git a/Tethering/src/com/android/networkstack/tethering/UpstreamNetworkMonitor.java b/Tethering/src/com/android/networkstack/tethering/UpstreamNetworkMonitor.java
index ac2aa7b..7a05d74 100644
--- a/Tethering/src/com/android/networkstack/tethering/UpstreamNetworkMonitor.java
+++ b/Tethering/src/com/android/networkstack/tethering/UpstreamNetworkMonitor.java
@@ -44,7 +44,6 @@
 import androidx.annotation.Nullable;
 
 import com.android.internal.annotations.VisibleForTesting;
-import com.android.internal.util.StateMachine;
 import com.android.net.module.util.SharedLog;
 import com.android.networkstack.apishim.ConnectivityManagerShimImpl;
 import com.android.networkstack.apishim.common.ConnectivityManagerShim;
@@ -111,9 +110,8 @@
 
     private final Context mContext;
     private final SharedLog mLog;
-    private final StateMachine mTarget;
     private final Handler mHandler;
-    private final int mWhat;
+    private final EventListener mEventListener;
     private final HashMap<Network, UpstreamNetworkState> mNetworkMap = new HashMap<>();
     private HashSet<IpPrefix> mLocalPrefixes;
     private ConnectivityManager mCM;
@@ -135,12 +133,11 @@
     private Network mDefaultInternetNetwork;
     private boolean mPreferTestNetworks;
 
-    public UpstreamNetworkMonitor(Context ctx, StateMachine tgt, SharedLog log, int what) {
+    public UpstreamNetworkMonitor(Context ctx, Handler h, SharedLog log, EventListener listener) {
         mContext = ctx;
-        mTarget = tgt;
-        mHandler = mTarget.getHandler();
+        mHandler = h;
         mLog = log.forSubComponent(TAG);
-        mWhat = what;
+        mEventListener = listener;
         mLocalPrefixes = new HashSet<>();
         mIsDefaultCellularUpstream = false;
         mCM = (ConnectivityManager) ctx.getSystemService(Context.CONNECTIVITY_SERVICE);
@@ -374,11 +371,12 @@
                     network, newNc));
         }
 
-        mNetworkMap.put(network, new UpstreamNetworkState(
-                prev.linkProperties, newNc, network));
+        final UpstreamNetworkState uns =
+                new UpstreamNetworkState(prev.linkProperties, newNc, network);
+        mNetworkMap.put(network, uns);
         // TODO: If sufficient information is available to select a more
         // preferable upstream, do so now and notify the target.
-        notifyTarget(EVENT_ON_CAPABILITIES, network);
+        mEventListener.onUpstreamEvent(EVENT_ON_CAPABILITIES, uns);
     }
 
     private @Nullable UpstreamNetworkState updateLinkProperties(@NonNull Network network,
@@ -411,7 +409,7 @@
     private void handleLinkProp(Network network, LinkProperties newLp) {
         final UpstreamNetworkState ns = updateLinkProperties(network, newLp);
         if (ns != null) {
-            notifyTarget(EVENT_ON_LINKPROPERTIES, ns);
+            mEventListener.onUpstreamEvent(EVENT_ON_LINKPROPERTIES, ns);
         }
     }
 
@@ -438,7 +436,7 @@
         // preferable upstream, do so now and notify the target.  Likewise,
         // if the current upstream network is gone, notify the target of the
         // fact that we now have no upstream at all.
-        notifyTarget(EVENT_ON_LOST, mNetworkMap.remove(network));
+        mEventListener.onUpstreamEvent(EVENT_ON_LOST, mNetworkMap.remove(network));
     }
 
     private void maybeHandleNetworkSwitch(@NonNull Network network) {
@@ -456,14 +454,14 @@
         // Default network changed. Update local data and notify tethering.
         Log.d(TAG, "New default Internet network: " + network);
         mDefaultInternetNetwork = network;
-        notifyTarget(EVENT_DEFAULT_SWITCHED, ns);
+        mEventListener.onUpstreamEvent(EVENT_DEFAULT_SWITCHED, ns);
     }
 
     private void recomputeLocalPrefixes() {
         final HashSet<IpPrefix> localPrefixes = allLocalPrefixes(mNetworkMap.values());
         if (!mLocalPrefixes.equals(localPrefixes)) {
             mLocalPrefixes = localPrefixes;
-            notifyTarget(NOTIFY_LOCAL_PREFIXES, localPrefixes.clone());
+            mEventListener.onUpstreamEvent(NOTIFY_LOCAL_PREFIXES, localPrefixes.clone());
         }
     }
 
@@ -502,12 +500,13 @@
                 // onLinkPropertiesChanged right after this method and mDefaultInternetNetwork will
                 // be updated then.
                 //
-                // Technically, not updating here isn't necessary, because the notifications to
-                // Tethering sent by notifyTarget are messages sent to a state machine running on
-                // the same thread as this method, and so cannot arrive until after this method has
-                // returned. However, it is not a good idea to rely on that because fact that
-                // Tethering uses multiple state machines running on the same thread is a major
-                // source of race conditions and something that should be fixed.
+                // Technically, mDefaultInternetNetwork could be updated here, because the
+                // Callback#onChange implementation sends messages to the state machine running
+                // on the same thread as this method. If there is new default network change,
+                // the message cannot arrive until onLinkPropertiesChanged returns.
+                // However, it is not a good idea to rely on that because fact that Tethering uses
+                // multiple state machines running on the same thread is a major source of race
+                // conditions and something that should be fixed.
                 //
                 // TODO: is it correct that this code always updates EntitlementManager?
                 // This code runs when the default network connects or changes capabilities, but the
@@ -551,7 +550,7 @@
                 mIsDefaultCellularUpstream = false;
                 mEntitlementMgr.notifyUpstream(false);
                 Log.d(TAG, "Lost default Internet network: " + network);
-                notifyTarget(EVENT_DEFAULT_SWITCHED, null);
+                mEventListener.onUpstreamEvent(EVENT_DEFAULT_SWITCHED, null);
                 return;
             }
 
@@ -569,14 +568,6 @@
         if (cb != null) cm().unregisterNetworkCallback(cb);
     }
 
-    private void notifyTarget(int which, Network network) {
-        notifyTarget(which, mNetworkMap.get(network));
-    }
-
-    private void notifyTarget(int which, Object obj) {
-        mTarget.sendMessage(mWhat, which, 0, obj);
-    }
-
     private static class TypeStatePair {
         public int type = TYPE_NONE;
         public UpstreamNetworkState ns = null;
@@ -698,4 +689,10 @@
     public void setPreferTestNetworks(boolean prefer) {
         mPreferTestNetworks = prefer;
     }
+
+    /** An interface to notify upstream network changes. */
+    public interface EventListener {
+        /** Notify the client of some event */
+        void onUpstreamEvent(int what, Object obj);
+    }
 }
diff --git a/Tethering/tests/unit/src/com/android/networkstack/tethering/TetheringTest.java b/Tethering/tests/unit/src/com/android/networkstack/tethering/TetheringTest.java
index 6eba590..5877fc5 100644
--- a/Tethering/tests/unit/src/com/android/networkstack/tethering/TetheringTest.java
+++ b/Tethering/tests/unit/src/com/android/networkstack/tethering/TetheringTest.java
@@ -187,7 +187,6 @@
 import androidx.test.filters.SmallTest;
 import androidx.test.runner.AndroidJUnit4;
 
-import com.android.internal.util.StateMachine;
 import com.android.internal.util.test.BroadcastInterceptingContext;
 import com.android.internal.util.test.FakeSettingsProvider;
 import com.android.net.module.util.CollectionUtils;
@@ -310,6 +309,7 @@
     private BroadcastReceiver mBroadcastReceiver;
     private Tethering mTethering;
     private TestTetheringEventCallback mTetheringEventCallback;
+    private Tethering.TetherMainSM mTetherMainSM;
     private PhoneStateListener mPhoneStateListener;
     private InterfaceConfigurationParcel mInterfaceConfiguration;
     private TetheringConfiguration mConfig;
@@ -319,6 +319,7 @@
     private SoftApCallback mSoftApCallback;
     private SoftApCallback mLocalOnlyHotspotCallback;
     private UpstreamNetworkMonitor mUpstreamNetworkMonitor;
+    private UpstreamNetworkMonitor.EventListener mEventListener;
     private TetheredInterfaceCallbackShim mTetheredInterfaceCallbackShim;
 
     private TestConnectivityManager mCm;
@@ -432,7 +433,6 @@
     }
 
     public class MockTetheringDependencies extends TetheringDependencies {
-        StateMachine mUpstreamNetworkMonitorSM;
         ArrayList<IpServer> mAllDownstreams;
 
         @Override
@@ -456,12 +456,12 @@
         }
 
         @Override
-        public UpstreamNetworkMonitor getUpstreamNetworkMonitor(Context ctx,
-                StateMachine target, SharedLog log, int what) {
+        public UpstreamNetworkMonitor getUpstreamNetworkMonitor(Context ctx, Handler h,
+                SharedLog log, UpstreamNetworkMonitor.EventListener listener) {
             // Use a real object instead of a mock so that some tests can use a real UNM and some
             // can use a mock.
-            mUpstreamNetworkMonitorSM = target;
-            mUpstreamNetworkMonitor = spy(super.getUpstreamNetworkMonitor(ctx, target, log, what));
+            mEventListener = listener;
+            mUpstreamNetworkMonitor = spy(super.getUpstreamNetworkMonitor(ctx, h, log, listener));
             return mUpstreamNetworkMonitor;
         }
 
@@ -688,6 +688,7 @@
     private void initTetheringOnTestThread() throws Exception {
         mLooper = new TestLooper();
         mTethering = new Tethering(mTetheringDependencies);
+        mTetherMainSM = mTethering.getTetherMainSMForTesting();
         verify(mStatsManager, times(1)).registerNetworkStatsProvider(anyString(), any());
         verify(mNetd).registerUnsolicitedEventListener(any());
         verifyDefaultNetworkRequestFiled();
@@ -1182,10 +1183,7 @@
         initTetheringUpstream(upstreamState);
 
         // Upstream LinkProperties changed: UpstreamNetworkMonitor sends EVENT_ON_LINKPROPERTIES.
-        mTetheringDependencies.mUpstreamNetworkMonitorSM.sendMessage(
-                Tethering.TetherMainSM.EVENT_UPSTREAM_CALLBACK,
-                UpstreamNetworkMonitor.EVENT_ON_LINKPROPERTIES,
-                0,
+        mEventListener.onUpstreamEvent(UpstreamNetworkMonitor.EVENT_ON_LINKPROPERTIES,
                 upstreamState);
         mLooper.dispatchAll();
 
@@ -2713,14 +2711,12 @@
     @Test
     public void testUpstreamNetworkChanged() throws Exception {
         initTetheringOnTestThread();
-        final Tethering.TetherMainSM stateMachine = (Tethering.TetherMainSM)
-                mTetheringDependencies.mUpstreamNetworkMonitorSM;
         final InOrder inOrder = inOrder(mNotificationUpdater);
 
         // Gain upstream.
         final UpstreamNetworkState upstreamState = buildMobileIPv4UpstreamState();
         initTetheringUpstream(upstreamState);
-        stateMachine.chooseUpstreamType(true);
+        mTetherMainSM.chooseUpstreamType(true);
         mTetheringEventCallback.expectUpstreamChanged(upstreamState.network);
         inOrder.verify(mNotificationUpdater)
                 .onUpstreamCapabilitiesChanged(upstreamState.networkCapabilities);
@@ -2728,7 +2724,7 @@
         // Set the upstream with the same network ID but different object and the same capability.
         final UpstreamNetworkState upstreamState2 = buildMobileIPv4UpstreamState();
         initTetheringUpstream(upstreamState2);
-        stateMachine.chooseUpstreamType(true);
+        mTetherMainSM.chooseUpstreamType(true);
         // Expect that no upstream change event and capabilities changed event.
         mTetheringEventCallback.assertNoUpstreamChangeCallback();
         inOrder.verify(mNotificationUpdater, never()).onUpstreamCapabilitiesChanged(any());
@@ -2738,17 +2734,17 @@
         assertFalse(upstreamState3.networkCapabilities.hasCapability(NET_CAPABILITY_VALIDATED));
         upstreamState3.networkCapabilities.addCapability(NET_CAPABILITY_VALIDATED);
         initTetheringUpstream(upstreamState3);
-        stateMachine.chooseUpstreamType(true);
+        mTetherMainSM.chooseUpstreamType(true);
         // Expect that no upstream change event and capabilities changed event.
         mTetheringEventCallback.assertNoUpstreamChangeCallback();
-        stateMachine.handleUpstreamNetworkMonitorCallback(EVENT_ON_CAPABILITIES, upstreamState3);
+        mTetherMainSM.handleUpstreamNetworkMonitorCallback(EVENT_ON_CAPABILITIES, upstreamState3);
         inOrder.verify(mNotificationUpdater)
                 .onUpstreamCapabilitiesChanged(upstreamState3.networkCapabilities);
 
 
         // Lose upstream.
         initTetheringUpstream(null);
-        stateMachine.chooseUpstreamType(true);
+        mTetherMainSM.chooseUpstreamType(true);
         mTetheringEventCallback.expectUpstreamChanged(NULL_NETWORK);
         inOrder.verify(mNotificationUpdater).onUpstreamCapabilitiesChanged(null);
     }
@@ -2756,17 +2752,15 @@
     @Test
     public void testUpstreamCapabilitiesChanged() throws Exception {
         initTetheringOnTestThread();
-        final Tethering.TetherMainSM stateMachine = (Tethering.TetherMainSM)
-                mTetheringDependencies.mUpstreamNetworkMonitorSM;
         final InOrder inOrder = inOrder(mNotificationUpdater);
         final UpstreamNetworkState upstreamState = buildMobileIPv4UpstreamState();
         initTetheringUpstream(upstreamState);
 
-        stateMachine.chooseUpstreamType(true);
+        mTetherMainSM.chooseUpstreamType(true);
         inOrder.verify(mNotificationUpdater)
                 .onUpstreamCapabilitiesChanged(upstreamState.networkCapabilities);
 
-        stateMachine.handleUpstreamNetworkMonitorCallback(EVENT_ON_CAPABILITIES, upstreamState);
+        mTetherMainSM.handleUpstreamNetworkMonitorCallback(EVENT_ON_CAPABILITIES, upstreamState);
         inOrder.verify(mNotificationUpdater)
                 .onUpstreamCapabilitiesChanged(upstreamState.networkCapabilities);
 
@@ -2775,7 +2769,7 @@
         // Expect that capability is changed with new capability VALIDATED.
         assertFalse(upstreamState.networkCapabilities.hasCapability(NET_CAPABILITY_VALIDATED));
         upstreamState.networkCapabilities.addCapability(NET_CAPABILITY_VALIDATED);
-        stateMachine.handleUpstreamNetworkMonitorCallback(EVENT_ON_CAPABILITIES, upstreamState);
+        mTetherMainSM.handleUpstreamNetworkMonitorCallback(EVENT_ON_CAPABILITIES, upstreamState);
         inOrder.verify(mNotificationUpdater)
                 .onUpstreamCapabilitiesChanged(upstreamState.networkCapabilities);
 
@@ -2784,7 +2778,7 @@
         final UpstreamNetworkState upstreamState2 = new UpstreamNetworkState(
                 upstreamState.linkProperties, upstreamState.networkCapabilities,
                 new Network(WIFI_NETID));
-        stateMachine.handleUpstreamNetworkMonitorCallback(EVENT_ON_CAPABILITIES, upstreamState2);
+        mTetherMainSM.handleUpstreamNetworkMonitorCallback(EVENT_ON_CAPABILITIES, upstreamState2);
         inOrder.verify(mNotificationUpdater, never()).onUpstreamCapabilitiesChanged(any());
     }
 
@@ -2907,11 +2901,7 @@
             final String iface, final int transportType) {
         final UpstreamNetworkState upstream = buildV4UpstreamState(ipv4Address, network, iface,
                 transportType);
-        mTetheringDependencies.mUpstreamNetworkMonitorSM.sendMessage(
-                Tethering.TetherMainSM.EVENT_UPSTREAM_CALLBACK,
-                UpstreamNetworkMonitor.EVENT_ON_LINKPROPERTIES,
-                0,
-                upstream);
+        mEventListener.onUpstreamEvent(UpstreamNetworkMonitor.EVENT_ON_LINKPROPERTIES, upstream);
         mLooper.dispatchAll();
     }
 
diff --git a/Tethering/tests/unit/src/com/android/networkstack/tethering/UpstreamNetworkMonitorTest.java b/Tethering/tests/unit/src/com/android/networkstack/tethering/UpstreamNetworkMonitorTest.java
index e756bd3..045c0cb 100644
--- a/Tethering/tests/unit/src/com/android/networkstack/tethering/UpstreamNetworkMonitorTest.java
+++ b/Tethering/tests/unit/src/com/android/networkstack/tethering/UpstreamNetworkMonitorTest.java
@@ -30,10 +30,12 @@
 import static org.junit.Assert.assertEquals;
 import static org.junit.Assert.assertFalse;
 import static org.junit.Assert.assertTrue;
+import static org.mockito.ArgumentMatchers.argThat;
 import static org.mockito.ArgumentMatchers.eq;
 import static org.mockito.Mockito.any;
 import static org.mockito.Mockito.anyInt;
 import static org.mockito.Mockito.anyString;
+import static org.mockito.Mockito.inOrder;
 import static org.mockito.Mockito.reset;
 import static org.mockito.Mockito.spy;
 import static org.mockito.Mockito.times;
@@ -51,27 +53,23 @@
 import android.net.NetworkRequest;
 import android.os.Build;
 import android.os.Handler;
-import android.os.Looper;
-import android.os.Message;
 import android.os.test.TestLooper;
 
 import androidx.test.filters.SmallTest;
 import androidx.test.runner.AndroidJUnit4;
 
-import com.android.internal.util.State;
-import com.android.internal.util.StateMachine;
 import com.android.net.module.util.SharedLog;
 import com.android.networkstack.tethering.TestConnectivityManager.NetworkRequestInfo;
 import com.android.networkstack.tethering.TestConnectivityManager.TestNetworkAgent;
 import com.android.testutils.DevSdkIgnoreRule;
 import com.android.testutils.DevSdkIgnoreRule.IgnoreAfter;
 
-import org.junit.After;
 import org.junit.Before;
 import org.junit.Rule;
 import org.junit.Test;
 import org.junit.runner.RunWith;
 import org.mockito.ArgumentCaptor;
+import org.mockito.InOrder;
 import org.mockito.Mock;
 import org.mockito.MockitoAnnotations;
 
@@ -84,8 +82,6 @@
 @RunWith(AndroidJUnit4.class)
 @SmallTest
 public class UpstreamNetworkMonitorTest {
-    private static final int EVENT_UNM_UPDATE = 1;
-
     private static final boolean INCLUDES = true;
     private static final boolean EXCLUDES = false;
 
@@ -102,12 +98,13 @@
     @Mock private EntitlementManager mEntitleMgr;
     @Mock private IConnectivityManager mCS;
     @Mock private SharedLog mLog;
+    @Mock private UpstreamNetworkMonitor.EventListener mListener;
 
-    private TestStateMachine mSM;
     private TestConnectivityManager mCM;
     private UpstreamNetworkMonitor mUNM;
 
     private final TestLooper mLooper = new TestLooper();
+    private InOrder mCallbackOrder;
 
     @Before public void setUp() throws Exception {
         MockitoAnnotations.initMocks(this);
@@ -117,17 +114,11 @@
         when(mLog.forSubComponent(anyString())).thenReturn(mLog);
         when(mEntitleMgr.isCellularUpstreamPermitted()).thenReturn(true);
 
+        mCallbackOrder = inOrder(mListener);
         mCM = spy(new TestConnectivityManager(mContext, mCS));
         when(mContext.getSystemService(eq(Context.CONNECTIVITY_SERVICE))).thenReturn(mCM);
-        mSM = new TestStateMachine(mLooper.getLooper());
-        mUNM = new UpstreamNetworkMonitor(mContext, mSM, mLog, EVENT_UNM_UPDATE);
-    }
-
-    @After public void tearDown() throws Exception {
-        if (mSM != null) {
-            mSM.quit();
-            mSM = null;
-        }
+        mUNM = new UpstreamNetworkMonitor(mContext, new Handler(mLooper.getLooper()), mLog,
+                mListener);
     }
 
     @Test
@@ -603,14 +594,17 @@
         mCM.makeDefaultNetwork(cellAgent);
         mLooper.dispatchAll();
         verifyCurrentLinkProperties(cellAgent);
-        int messageIndex = mSM.messages.size() - 1;
+        verifyNotifyNetworkCapabilitiesChange(cellAgent.networkCapabilities);
+        verifyNotifyLinkPropertiesChange(cellLp);
+        verifyNotifyDefaultSwitch(cellAgent);
+        verifyNoMoreInteractions(mListener);
 
         addLinkAddresses(cellLp, ipv6Addr1);
         mCM.sendLinkProperties(cellAgent, false /* updateDefaultFirst */);
         mLooper.dispatchAll();
         verifyCurrentLinkProperties(cellAgent);
-        verifyNotifyLinkPropertiesChange(messageIndex);
-        messageIndex = mSM.messages.size() - 1;
+        verifyNotifyLinkPropertiesChange(cellLp);
+        verifyNoMoreInteractions(mListener);
 
         removeLinkAddresses(cellLp, ipv6Addr1);
         addLinkAddresses(cellLp, ipv6Addr2);
@@ -618,7 +612,8 @@
         mLooper.dispatchAll();
         assertEquals(cellAgent.linkProperties, mUNM.getCurrentPreferredUpstream().linkProperties);
         verifyCurrentLinkProperties(cellAgent);
-        verifyNotifyLinkPropertiesChange(messageIndex);
+        verifyNotifyLinkPropertiesChange(cellLp);
+        verifyNoMoreInteractions(mListener);
     }
 
     private void verifyCurrentLinkProperties(TestNetworkAgent agent) {
@@ -626,12 +621,33 @@
         assertEquals(agent.linkProperties, mUNM.getCurrentPreferredUpstream().linkProperties);
     }
 
-    private void verifyNotifyLinkPropertiesChange(int lastMessageIndex) {
-        assertEquals(UpstreamNetworkMonitor.EVENT_ON_LINKPROPERTIES,
-                mSM.messages.get(++lastMessageIndex).arg1);
-        assertEquals(UpstreamNetworkMonitor.NOTIFY_LOCAL_PREFIXES,
-                mSM.messages.get(++lastMessageIndex).arg1);
-        assertEquals(lastMessageIndex + 1, mSM.messages.size());
+    private void verifyNotifyNetworkCapabilitiesChange(final NetworkCapabilities cap) {
+        mCallbackOrder.verify(mListener).onUpstreamEvent(
+                eq(UpstreamNetworkMonitor.EVENT_ON_CAPABILITIES),
+                argThat(uns -> uns instanceof UpstreamNetworkState
+                    && cap.equals(((UpstreamNetworkState) uns).networkCapabilities)));
+
+    }
+
+    private void verifyNotifyLinkPropertiesChange(final LinkProperties lp) {
+        mCallbackOrder.verify(mListener).onUpstreamEvent(
+                eq(UpstreamNetworkMonitor.EVENT_ON_LINKPROPERTIES),
+                argThat(uns -> uns instanceof UpstreamNetworkState
+                    && lp.equals(((UpstreamNetworkState) uns).linkProperties)));
+
+        mCallbackOrder.verify(mListener).onUpstreamEvent(
+                eq(UpstreamNetworkMonitor.NOTIFY_LOCAL_PREFIXES), any());
+    }
+
+    private void verifyNotifyDefaultSwitch(TestNetworkAgent agent) {
+        mCallbackOrder.verify(mListener).onUpstreamEvent(
+                eq(UpstreamNetworkMonitor.EVENT_DEFAULT_SWITCHED),
+                argThat(uns ->
+                    uns instanceof UpstreamNetworkState
+                    && agent.networkId.equals(((UpstreamNetworkState) uns).network)
+                    && agent.linkProperties.equals(((UpstreamNetworkState) uns).linkProperties)
+                    && agent.networkCapabilities.equals(
+                        ((UpstreamNetworkState) uns).networkCapabilities)));
     }
 
     private void addLinkAddresses(LinkProperties lp, String... addrs) {
@@ -673,33 +689,6 @@
         return false;
     }
 
-    public static class TestStateMachine extends StateMachine {
-        public final ArrayList<Message> messages = new ArrayList<>();
-        private final State mLoggingState = new LoggingState();
-
-        class LoggingState extends State {
-            @Override public void enter() {
-                messages.clear();
-            }
-
-            @Override public void exit() {
-                messages.clear();
-            }
-
-            @Override public boolean processMessage(Message msg) {
-                messages.add(msg);
-                return true;
-            }
-        }
-
-        public TestStateMachine(Looper looper) {
-            super("UpstreamNetworkMonitor.TestStateMachine", looper);
-            addState(mLoggingState);
-            setInitialState(mLoggingState);
-            super.start();
-        }
-    }
-
     static void assertPrefixSet(Set<IpPrefix> prefixes, boolean expectation, String... expected) {
         final Set<String> expectedSet = new HashSet<>();
         Collections.addAll(expectedSet, expected);
diff --git a/framework/Android.bp b/framework/Android.bp
index fab37e9..73a1ed0 100644
--- a/framework/Android.bp
+++ b/framework/Android.bp
@@ -94,7 +94,9 @@
         "framework-wifi.stubs.module_lib",
     ],
     static_libs: [
-        "mdns_aidl_interface-lateststable-java",
+        // Not using the latest stable version because all functions in the latest version of
+        // mdns_aidl_interface are deprecated.
+        "mdns_aidl_interface-V1-java",
         "modules-utils-backgroundthread",
         "modules-utils-build",
         "modules-utils-preconditions",
diff --git a/service/Android.bp b/service/Android.bp
index 76741bc..e2dab9e 100644
--- a/service/Android.bp
+++ b/service/Android.bp
@@ -185,7 +185,7 @@
         "androidx.annotation_annotation",
         "connectivity-net-module-utils-bpf",
         "connectivity_native_aidl_interface-lateststable-java",
-        "dnsresolver_aidl_interface-V12-java",
+        "dnsresolver_aidl_interface-V13-java",
         "modules-utils-shell-command-handler",
         "net-utils-device-common",
         "net-utils-device-common-ip",
diff --git a/staticlibs/Android.bp b/staticlibs/Android.bp
index 6325b46..9f1debc 100644
--- a/staticlibs/Android.bp
+++ b/staticlibs/Android.bp
@@ -191,7 +191,7 @@
 java_library {
     name: "net-utils-device-common-netlink",
     srcs: [
-        "device/com/android/net/module/util/netlink/*.java",
+        "device/com/android/net/module/util/netlink/**/*.java",
     ],
     sdk_version: "module_current",
     min_sdk_version: "30",
diff --git a/staticlibs/device/com/android/net/module/util/netlink/IpSecStructXfrmAddressT.java b/staticlibs/device/com/android/net/module/util/netlink/xfrm/StructXfrmAddressT.java
similarity index 86%
rename from staticlibs/device/com/android/net/module/util/netlink/IpSecStructXfrmAddressT.java
rename to staticlibs/device/com/android/net/module/util/netlink/xfrm/StructXfrmAddressT.java
index 4c19887..cef1f56 100644
--- a/staticlibs/device/com/android/net/module/util/netlink/IpSecStructXfrmAddressT.java
+++ b/staticlibs/device/com/android/net/module/util/netlink/xfrm/StructXfrmAddressT.java
@@ -13,7 +13,9 @@
  * See the License for the specific language governing permissions and
  * limitations under the License.
  */
-package com.android.net.module.util.netlink;
+package com.android.net.module.util.netlink.xfrm;
+
+import static com.android.net.module.util.NetworkStackConstants.IPV4_ADDR_LEN;
 
 import android.system.OsConstants;
 
@@ -41,21 +43,19 @@
  *
  * @hide
  */
-public class IpSecStructXfrmAddressT extends Struct {
-    private static final int IPV4_ADDRESS_LEN = 4;
-
+public class StructXfrmAddressT extends Struct {
     public static final int STRUCT_SIZE = 16;
 
     @Field(order = 0, type = Type.ByteArray, arraysize = STRUCT_SIZE)
     public final byte[] address;
 
     // Constructor that allows Strutc.parse(Class<T>, ByteBuffer) to work
-    public IpSecStructXfrmAddressT(@NonNull byte[] address) {
+    public StructXfrmAddressT(@NonNull final byte[] address) {
         this.address = address.clone();
     }
 
     // Constructor to build a new message
-    public IpSecStructXfrmAddressT(@NonNull InetAddress inetAddress) {
+    public StructXfrmAddressT(@NonNull final InetAddress inetAddress) {
         this.address = new byte[STRUCT_SIZE];
         final byte[] addressBytes = inetAddress.getAddress();
         System.arraycopy(addressBytes, 0, address, 0, addressBytes.length);
@@ -67,7 +67,7 @@
         if (family == OsConstants.AF_INET6) {
             addressBytes = this.address;
         } else if (family == OsConstants.AF_INET) {
-            addressBytes = new byte[IPV4_ADDRESS_LEN];
+            addressBytes = new byte[IPV4_ADDR_LEN];
             System.arraycopy(this.address, 0, addressBytes, 0, addressBytes.length);
         } else {
             throw new IllegalArgumentException("Invalid IP family " + family);
diff --git a/staticlibs/device/com/android/net/module/util/netlink/IpSecStructXfrmUsersaId.java b/staticlibs/device/com/android/net/module/util/netlink/xfrm/StructXfrmUsersaId.java
similarity index 76%
rename from staticlibs/device/com/android/net/module/util/netlink/IpSecStructXfrmUsersaId.java
rename to staticlibs/device/com/android/net/module/util/netlink/xfrm/StructXfrmUsersaId.java
index 6f7b656..5ebc69c 100644
--- a/staticlibs/device/com/android/net/module/util/netlink/IpSecStructXfrmUsersaId.java
+++ b/staticlibs/device/com/android/net/module/util/netlink/xfrm/StructXfrmUsersaId.java
@@ -14,7 +14,7 @@
  * limitations under the License.
  */
 
-package com.android.net.module.util.netlink;
+package com.android.net.module.util.netlink.xfrm;
 
 import androidx.annotation.NonNull;
 
@@ -40,7 +40,7 @@
  *
  * @hide
  */
-public class IpSecStructXfrmUsersaId extends Struct {
+public class StructXfrmUsersaId extends Struct {
     public static final int STRUCT_SIZE = 24;
 
     @Field(order = 0, type = Type.ByteArray, arraysize = 16)
@@ -55,23 +55,23 @@
     @Field(order = 3, type = Type.U8, padding = 1)
     public final short proto;
 
-    @Computed private final IpSecStructXfrmAddressT mDestXfrmAddressT;
+    @Computed private final StructXfrmAddressT mDestXfrmAddressT;
 
     // Constructor that allows Strutc.parse(Class<T>, ByteBuffer) to work
-    public IpSecStructXfrmUsersaId(
-            @NonNull byte[] nestedStructDAddr, long spi, int family, short proto) {
+    public StructXfrmUsersaId(
+            @NonNull final byte[] nestedStructDAddr, long spi, int family, short proto) {
         this.nestedStructDAddr = nestedStructDAddr.clone();
         this.spi = spi;
         this.family = family;
         this.proto = proto;
 
-        mDestXfrmAddressT = new IpSecStructXfrmAddressT(this.nestedStructDAddr);
+        mDestXfrmAddressT = new StructXfrmAddressT(this.nestedStructDAddr);
     }
 
     // Constructor to build a new message
-    public IpSecStructXfrmUsersaId(
-            @NonNull InetAddress destAddress, long spi, int family, short proto) {
-        this(new IpSecStructXfrmAddressT(destAddress).writeToBytes(), spi, family, proto);
+    public StructXfrmUsersaId(
+            @NonNull final InetAddress destAddress, long spi, int family, short proto) {
+        this(new StructXfrmAddressT(destAddress).writeToBytes(), spi, family, proto);
     }
 
     /** Return the destination address */
diff --git a/staticlibs/device/com/android/net/module/util/netlink/IpSecXfrmNetlinkMessage.java b/staticlibs/device/com/android/net/module/util/netlink/xfrm/XfrmNetlinkMessage.java
similarity index 81%
rename from staticlibs/device/com/android/net/module/util/netlink/IpSecXfrmNetlinkMessage.java
rename to staticlibs/device/com/android/net/module/util/netlink/xfrm/XfrmNetlinkMessage.java
index 8ad784b..ee34e57 100644
--- a/staticlibs/device/com/android/net/module/util/netlink/IpSecXfrmNetlinkMessage.java
+++ b/staticlibs/device/com/android/net/module/util/netlink/xfrm/XfrmNetlinkMessage.java
@@ -14,21 +14,24 @@
  * limitations under the License.
  */
 
-package com.android.net.module.util.netlink;
+package com.android.net.module.util.netlink.xfrm;
 
 import androidx.annotation.NonNull;
 
+import com.android.net.module.util.netlink.NetlinkMessage;
+import com.android.net.module.util.netlink.StructNlMsgHdr;
+
 /** Base calss for XFRM netlink messages */
 // Developer notes: The Linux kernel includes a number of XFRM structs that are not standard netlink
 // attributes (e.g., xfrm_usersa_id). These structs are unlikely to change size, so this XFRM
 // netlink message implementation assumes their sizes will remain stable. If any non-attribute
 // struct size changes, it should be caught by CTS and then developers should add
 // kernel-version-based behvaiours.
-public abstract class IpSecXfrmNetlinkMessage extends NetlinkMessage {
+public abstract class XfrmNetlinkMessage extends NetlinkMessage {
     // TODO: STOPSHIP: b/308011229 Remove it when OsConstants.IPPROTO_ESP is exposed
     public static final int IPPROTO_ESP = 50;
 
-    public IpSecXfrmNetlinkMessage(@NonNull StructNlMsgHdr header) {
+    public XfrmNetlinkMessage(@NonNull final StructNlMsgHdr header) {
         super(header);
     }
 
diff --git a/staticlibs/netd/Android.bp b/staticlibs/netd/Android.bp
index 56565ed..637a938 100644
--- a/staticlibs/netd/Android.bp
+++ b/staticlibs/netd/Android.bp
@@ -225,19 +225,6 @@
 
 }
 
-java_library {
-    name: "mdns_aidl_interface-lateststable-java",
-    sdk_version: "module_current",
-    min_sdk_version: "30",
-    static_libs: [
-        "mdns_aidl_interface-V1-java",
-    ],
-    apex_available: [
-        "//apex_available:platform",
-        "com.android.tethering",
-    ],
-}
-
 aidl_interface {
     name: "mdns_aidl_interface",
     local_include_dir: "binder",
diff --git a/staticlibs/tests/unit/src/com/android/net/module/util/netlink/IpSecStructXfrmUsersaIdTest.java b/staticlibs/tests/unit/src/com/android/net/module/util/netlink/xfrm/StructXfrmUsersaIdTest.java
similarity index 84%
rename from staticlibs/tests/unit/src/com/android/net/module/util/netlink/IpSecStructXfrmUsersaIdTest.java
rename to staticlibs/tests/unit/src/com/android/net/module/util/netlink/xfrm/StructXfrmUsersaIdTest.java
index 4266f68..52fd591 100644
--- a/staticlibs/tests/unit/src/com/android/net/module/util/netlink/IpSecStructXfrmUsersaIdTest.java
+++ b/staticlibs/tests/unit/src/com/android/net/module/util/netlink/xfrm/StructXfrmUsersaIdTest.java
@@ -14,9 +14,9 @@
  * limitations under the License.
  */
 
-package com.android.net.module.util.netlink;
+package com.android.net.module.util.netlink.xfrm;
 
-import static com.android.net.module.util.netlink.IpSecXfrmNetlinkMessage.IPPROTO_ESP;
+import static com.android.net.module.util.netlink.xfrm.XfrmNetlinkMessage.IPPROTO_ESP;
 
 import static org.junit.Assert.assertArrayEquals;
 import static org.junit.Assert.assertEquals;
@@ -38,7 +38,7 @@
 
 @RunWith(AndroidJUnit4.class)
 @SmallTest
-public class IpSecStructXfrmUsersaIdTest {
+public class StructXfrmUsersaIdTest {
     private static final String EXPECTED_HEX_STRING =
             "C0000201000000000000000000000000" + "7768440002003200";
     private static final byte[] EXPECTED_HEX = HexDump.hexStringToByteArray(EXPECTED_HEX_STRING);
@@ -50,8 +50,7 @@
 
     @Test
     public void testEncode() throws Exception {
-        final IpSecStructXfrmUsersaId struct =
-                new IpSecStructXfrmUsersaId(DEST_ADDRESS, SPI, FAMILY, PROTO);
+        final StructXfrmUsersaId struct = new StructXfrmUsersaId(DEST_ADDRESS, SPI, FAMILY, PROTO);
 
         ByteBuffer buffer = ByteBuffer.allocate(EXPECTED_HEX.length);
         buffer.order(ByteOrder.nativeOrder());
@@ -65,8 +64,8 @@
         final ByteBuffer buffer = ByteBuffer.wrap(EXPECTED_HEX);
         buffer.order(ByteOrder.nativeOrder());
 
-        final IpSecStructXfrmUsersaId struct =
-                IpSecStructXfrmUsersaId.parse(IpSecStructXfrmUsersaId.class, buffer);
+        final StructXfrmUsersaId struct =
+                StructXfrmUsersaId.parse(StructXfrmUsersaId.class, buffer);
 
         assertEquals(DEST_ADDRESS, struct.getDestAddress());
         assertEquals(SPI, struct.spi);
diff --git a/tests/unit/java/com/android/server/connectivity/DnsManagerTest.java b/tests/unit/java/com/android/server/connectivity/DnsManagerTest.java
index 545ed16..afb9abd 100644
--- a/tests/unit/java/com/android/server/connectivity/DnsManagerTest.java
+++ b/tests/unit/java/com/android/server/connectivity/DnsManagerTest.java
@@ -140,7 +140,8 @@
         assertResolverOptionsEquals(actual.resolverOptions, expected.resolverOptions);
         assertContainsExactly(actual.transportTypes, expected.transportTypes);
         assertEquals(actual.meteredNetwork, expected.meteredNetwork);
-        assertFieldCountEquals(17, ResolverParamsParcel.class);
+        assertEquals(actual.dohParams, expected.dohParams);
+        assertFieldCountEquals(18, ResolverParamsParcel.class);
     }
 
     @Before
@@ -381,6 +382,7 @@
         expectedParams.transportTypes = TEST_TRANSPORT_TYPES;
         expectedParams.resolverOptions = null;
         expectedParams.meteredNetwork = true;
+        expectedParams.dohParams = null;
         assertResolverParamsEquals(actualParams, expectedParams);
     }