diff --git a/service-t/src/com/android/server/NsdService.java b/service-t/src/com/android/server/NsdService.java
index 47a1022..25aa693 100644
--- a/service-t/src/com/android/server/NsdService.java
+++ b/service-t/src/com/android/server/NsdService.java
@@ -17,6 +17,8 @@
 package com.android.server;
 
 import static android.net.ConnectivityManager.NETID_UNSET;
+import static android.net.NetworkCapabilities.TRANSPORT_VPN;
+import static android.net.NetworkCapabilities.TRANSPORT_WIFI;
 import static android.net.nsd.NsdManager.MDNS_DISCOVERY_MANAGER_EVENT;
 import static android.net.nsd.NsdManager.MDNS_SERVICE_EVENT;
 import static android.net.nsd.NsdManager.RESOLVE_SERVICE_SUCCEEDED;
@@ -27,6 +29,7 @@
 
 import android.annotation.NonNull;
 import android.annotation.Nullable;
+import android.app.ActivityManager;
 import android.content.Context;
 import android.content.Intent;
 import android.net.ConnectivityManager;
@@ -45,6 +48,7 @@
 import android.net.nsd.MDnsManager;
 import android.net.nsd.NsdManager;
 import android.net.nsd.NsdServiceInfo;
+import android.net.wifi.WifiManager;
 import android.os.Binder;
 import android.os.Handler;
 import android.os.HandlerThread;
@@ -53,7 +57,9 @@
 import android.os.Message;
 import android.os.RemoteException;
 import android.os.UserHandle;
+import android.provider.DeviceConfig;
 import android.text.TextUtils;
+import android.util.ArraySet;
 import android.util.Log;
 import android.util.Pair;
 import android.util.SparseArray;
@@ -62,6 +68,7 @@
 import com.android.internal.util.IndentingPrintWriter;
 import com.android.internal.util.State;
 import com.android.internal.util.StateMachine;
+import com.android.net.module.util.CollectionUtils;
 import com.android.net.module.util.DeviceConfigUtils;
 import com.android.net.module.util.InetAddressUtils;
 import com.android.net.module.util.PermissionUtils;
@@ -69,6 +76,7 @@
 import com.android.server.connectivity.mdns.ExecutorProvider;
 import com.android.server.connectivity.mdns.MdnsAdvertiser;
 import com.android.server.connectivity.mdns.MdnsDiscoveryManager;
+import com.android.server.connectivity.mdns.MdnsInterfaceSocket;
 import com.android.server.connectivity.mdns.MdnsMultinetworkSocketClient;
 import com.android.server.connectivity.mdns.MdnsSearchOptions;
 import com.android.server.connectivity.mdns.MdnsServiceBrowserListener;
@@ -141,6 +149,14 @@
             "mdns_advertiser_allowlist_";
     private static final String MDNS_ALLOWLIST_FLAG_SUFFIX = "_version";
 
+    @VisibleForTesting
+    static final String MDNS_CONFIG_RUNNING_APP_ACTIVE_IMPORTANCE_CUTOFF =
+            "mdns_config_running_app_active_importance_cutoff";
+    @VisibleForTesting
+    static final int DEFAULT_RUNNING_APP_ACTIVE_IMPORTANCE_CUTOFF =
+            ActivityManager.RunningAppProcessInfo.IMPORTANCE_FOREGROUND;
+    private final int mRunningAppActiveImportanceCutoff;
+
     public static final boolean DBG = Log.isLoggable(TAG, Log.DEBUG);
     private static final long CLEANUP_DELAY_MS = 10000;
     private static final int IFACE_IDX_ANY = 0;
@@ -175,6 +191,16 @@
     /* A map from unique id to client info */
     private final SparseArray<ClientInfo> mIdToClientInfoMap= new SparseArray<>();
 
+    // Note this is not final to avoid depending on the Wi-Fi service starting before NsdService
+    @Nullable
+    private WifiManager.MulticastLock mHeldMulticastLock;
+    // Fulfilled network requests that require the Wi-Fi lock: key is the obtained Network
+    // (non-null), value is the requested Network (nullable)
+    @NonNull
+    private final ArraySet<Network> mWifiLockRequiredNetworks = new ArraySet<>();
+    @NonNull
+    private final ArraySet<Integer> mRunningAppActiveUids = new ArraySet<>();
+
     private final long mCleanupDelayMs;
 
     private static final int INVALID_ID = 0;
@@ -299,6 +325,104 @@
         }
     }
 
+    private class SocketRequestMonitor implements MdnsSocketProvider.SocketRequestMonitor {
+        @Override
+        public void onSocketRequestFulfilled(@Nullable Network socketNetwork,
+                @NonNull MdnsInterfaceSocket socket, @NonNull int[] transports) {
+            // The network may be null for Wi-Fi SoftAp interfaces (tethering), but there is no APF
+            // filtering on such interfaces, so taking the multicast lock is not necessary to
+            // disable APF filtering of multicast.
+            if (socketNetwork == null
+                    || !CollectionUtils.contains(transports, TRANSPORT_WIFI)
+                    || CollectionUtils.contains(transports, TRANSPORT_VPN)) {
+                return;
+            }
+
+            if (mWifiLockRequiredNetworks.add(socketNetwork)) {
+                updateMulticastLock();
+            }
+        }
+
+        @Override
+        public void onSocketDestroyed(@Nullable Network socketNetwork,
+                @NonNull MdnsInterfaceSocket socket) {
+            if (mWifiLockRequiredNetworks.remove(socketNetwork)) {
+                updateMulticastLock();
+            }
+        }
+    }
+
+    private class UidImportanceListener implements ActivityManager.OnUidImportanceListener {
+        private final Handler mHandler;
+
+        private UidImportanceListener(Handler handler) {
+            mHandler = handler;
+        }
+
+        @Override
+        public void onUidImportance(int uid, int importance) {
+            mHandler.post(() -> handleUidImportanceChanged(uid, importance));
+        }
+    }
+
+    private void handleUidImportanceChanged(int uid, int importance) {
+        // Lower importance values are more "important"
+        final boolean modified = importance <= mRunningAppActiveImportanceCutoff
+                ? mRunningAppActiveUids.add(uid)
+                : mRunningAppActiveUids.remove(uid);
+        if (modified) {
+            updateMulticastLock();
+        }
+    }
+
+    /**
+     * Take or release the lock based on updated internal state.
+     *
+     * This determines whether the lock needs to be held based on
+     * {@link #mWifiLockRequiredNetworks}, {@link #mRunningAppActiveUids} and
+     * {@link ClientInfo#mClientRequests}, so it must be called after any of the these have been
+     * updated.
+     */
+    private void updateMulticastLock() {
+        final int needsLockUid = getMulticastLockNeededUid();
+        if (needsLockUid >= 0 && mHeldMulticastLock == null) {
+            final WifiManager wm = mContext.getSystemService(WifiManager.class);
+            if (wm == null) {
+                Log.wtf(TAG, "Got a TRANSPORT_WIFI network without WifiManager");
+                return;
+            }
+            mHeldMulticastLock = wm.createMulticastLock(TAG);
+            mHeldMulticastLock.acquire();
+            mServiceLogs.log("Taking multicast lock for uid " + needsLockUid);
+        } else if (needsLockUid < 0 && mHeldMulticastLock != null) {
+            mHeldMulticastLock.release();
+            mHeldMulticastLock = null;
+            mServiceLogs.log("Released multicast lock");
+        }
+    }
+
+    /**
+     * @return The UID of an app requiring the multicast lock, or -1 if none.
+     */
+    private int getMulticastLockNeededUid() {
+        if (mWifiLockRequiredNetworks.size() == 0) {
+            // Return early if NSD is not active, or not on any relevant network
+            return -1;
+        }
+        for (int i = 0; i < mIdToClientInfoMap.size(); i++) {
+            final ClientInfo clientInfo = mIdToClientInfoMap.valueAt(i);
+            if (!mRunningAppActiveUids.contains(clientInfo.mUid)) {
+                // Ignore non-active UIDs
+                continue;
+            }
+
+            if (clientInfo.hasAnyJavaBackendRequestForNetworks(mWifiLockRequiredNetworks)) {
+                return clientInfo.mUid;
+            }
+        }
+        return -1;
+    }
+
     /**
      * Data class of mdns service callback information.
      */
@@ -404,7 +528,7 @@
                         try {
                             cb.asBinder().linkToDeath(arg.connector, 0);
                             final String tag = "Client" + arg.uid + "-" + mClientNumberId++;
-                            cInfo = new ClientInfo(cb, arg.useJavaBackend,
+                            cInfo = new ClientInfo(cb, arg.uid, arg.useJavaBackend,
                                     mServiceLogs.forSubComponent(tag));
                             mClients.put(arg.connector, cInfo);
                         } catch (RemoteException e) {
@@ -529,9 +653,11 @@
             }
 
             private void storeAdvertiserRequestMap(int clientId, int globalId,
-                    ClientInfo clientInfo) {
-                clientInfo.mClientRequests.put(clientId, new AdvertiserClientRequest(globalId));
+                    ClientInfo clientInfo, @Nullable Network requestedNetwork) {
+                clientInfo.mClientRequests.put(clientId,
+                        new AdvertiserClientRequest(globalId, requestedNetwork));
                 mIdToClientInfoMap.put(globalId, clientInfo);
+                updateMulticastLock();
             }
 
             private void removeRequestMap(int clientId, int globalId, ClientInfo clientInfo) {
@@ -544,14 +670,17 @@
                     maybeScheduleStop();
                 } else {
                     maybeStopMonitoringSocketsIfNoActiveRequest();
+                    updateMulticastLock();
                 }
             }
 
             private void storeDiscoveryManagerRequestMap(int clientId, int globalId,
-                    MdnsListener listener, ClientInfo clientInfo) {
+                    MdnsListener listener, ClientInfo clientInfo,
+                    @Nullable Network requestedNetwork) {
                 clientInfo.mClientRequests.put(clientId,
-                        new DiscoveryManagerRequest(globalId, listener));
+                        new DiscoveryManagerRequest(globalId, listener, requestedNetwork));
                 mIdToClientInfoMap.put(globalId, clientInfo);
+                updateMulticastLock();
             }
 
             /**
@@ -628,7 +757,8 @@
                             }
                             mMdnsDiscoveryManager.registerListener(
                                     listenServiceType, listener, optionsBuilder.build());
-                            storeDiscoveryManagerRequestMap(clientId, id, listener, clientInfo);
+                            storeDiscoveryManagerRequestMap(clientId, id, listener, clientInfo,
+                                    info.getNetwork());
                             clientInfo.onDiscoverServicesStarted(clientId, info);
                             clientInfo.log("Register a DiscoveryListener " + id
                                     + " for service type:" + listenServiceType);
@@ -728,7 +858,8 @@
                             // Name._subtype._sub._type._tcp, which is incorrect
                             // (it should be Name._type._tcp).
                             mAdvertiser.addService(id, serviceInfo, typeSubtype.second);
-                            storeAdvertiserRequestMap(clientId, id, clientInfo);
+                            storeAdvertiserRequestMap(clientId, id, clientInfo,
+                                    serviceInfo.getNetwork());
                         } else {
                             maybeStartDaemon();
                             if (registerService(id, serviceInfo)) {
@@ -818,7 +949,8 @@
                                     .build();
                             mMdnsDiscoveryManager.registerListener(
                                     resolveServiceType, listener, options);
-                            storeDiscoveryManagerRequestMap(clientId, id, listener, clientInfo);
+                            storeDiscoveryManagerRequestMap(clientId, id, listener, clientInfo,
+                                    info.getNetwork());
                             clientInfo.log("Register a ResolutionListener " + id
                                     + " for service type:" + resolveServiceType);
                         } else {
@@ -912,7 +1044,8 @@
                                 .build();
                         mMdnsDiscoveryManager.registerListener(
                                 resolveServiceType, listener, options);
-                        storeDiscoveryManagerRequestMap(clientId, id, listener, clientInfo);
+                        storeDiscoveryManagerRequestMap(clientId, id, listener, clientInfo,
+                                info.getNetwork());
                         clientInfo.log("Register a ServiceInfoListener " + id
                                 + " for service type:" + resolveServiceType);
                         break;
@@ -1389,10 +1522,20 @@
         mDeps = deps;
 
         mMdnsSocketProvider = deps.makeMdnsSocketProvider(ctx, handler.getLooper(),
-                LOGGER.forSubComponent("MdnsSocketProvider"));
+                LOGGER.forSubComponent("MdnsSocketProvider"), new SocketRequestMonitor());
         // Netlink monitor starts on boot, and intentionally never stopped, to ensure that all
         // address events are received.
         handler.post(mMdnsSocketProvider::startNetLinkMonitor);
+
+        // NsdService is started after ActivityManager (startOtherServices in SystemServer, vs.
+        // startBootstrapServices).
+        mRunningAppActiveImportanceCutoff = mDeps.getDeviceConfigInt(
+                MDNS_CONFIG_RUNNING_APP_ACTIVE_IMPORTANCE_CUTOFF,
+                DEFAULT_RUNNING_APP_ACTIVE_IMPORTANCE_CUTOFF);
+        final ActivityManager am = ctx.getSystemService(ActivityManager.class);
+        am.addOnUidImportanceListener(new UidImportanceListener(handler),
+                mRunningAppActiveImportanceCutoff);
+
         mMdnsSocketClient =
                 new MdnsMultinetworkSocketClient(handler.getLooper(), mMdnsSocketProvider);
         mMdnsDiscoveryManager = deps.makeMdnsDiscoveryManager(new ExecutorProvider(),
@@ -1471,8 +1614,23 @@
          * @see MdnsSocketProvider
          */
         public MdnsSocketProvider makeMdnsSocketProvider(@NonNull Context context,
-                @NonNull Looper looper, @NonNull SharedLog sharedLog) {
-            return new MdnsSocketProvider(context, looper, sharedLog);
+                @NonNull Looper looper, @NonNull SharedLog sharedLog,
+                @NonNull MdnsSocketProvider.SocketRequestMonitor socketCreationCallback) {
+            return new MdnsSocketProvider(context, looper, sharedLog, socketCreationCallback);
+        }
+
+        /**
+         * @see DeviceConfig#getInt(String, String, int)
+         */
+        public int getDeviceConfigInt(@NonNull String config, int defaultValue) {
+            return DeviceConfig.getInt(NAMESPACE_TETHERING, config, defaultValue);
+        }
+
+        /**
+         * @see Binder#getCallingUid()
+         */
+        public int getCallingUid() {
+            return Binder.getCallingUid();
         }
     }
 
@@ -1626,7 +1784,7 @@
         final INsdServiceConnector connector = new NsdServiceConnector();
         mNsdStateMachine.sendMessage(mNsdStateMachine.obtainMessage(NsdManager.REGISTER_CLIENT,
                 new ConnectorArgs((NsdServiceConnector) connector, cb, useJavaBackend,
-                        Binder.getCallingUid())));
+                        mDeps.getCallingUid())));
         return connector;
     }
 
@@ -1857,18 +2015,34 @@
         }
     }
 
-    private static class AdvertiserClientRequest extends ClientRequest {
-        private AdvertiserClientRequest(int globalId) {
+    private abstract static class JavaBackendClientRequest extends ClientRequest {
+        @Nullable
+        private final Network mRequestedNetwork;
+
+        private JavaBackendClientRequest(int globalId, @Nullable Network requestedNetwork) {
             super(globalId);
+            mRequestedNetwork = requestedNetwork;
+        }
+
+        @Nullable
+        public Network getRequestedNetwork() {
+            return mRequestedNetwork;
         }
     }
 
-    private static class DiscoveryManagerRequest extends ClientRequest {
+    private static class AdvertiserClientRequest extends JavaBackendClientRequest {
+        private AdvertiserClientRequest(int globalId, @Nullable Network requestedNetwork) {
+            super(globalId, requestedNetwork);
+        }
+    }
+
+    private static class DiscoveryManagerRequest extends JavaBackendClientRequest {
         @NonNull
         private final MdnsListener mListener;
 
-        private DiscoveryManagerRequest(int globalId, @NonNull MdnsListener listener) {
-            super(globalId);
+        private DiscoveryManagerRequest(int globalId, @NonNull MdnsListener listener,
+                @Nullable Network requestedNetwork) {
+            super(globalId, requestedNetwork);
             mListener = listener;
         }
     }
@@ -1886,13 +2060,16 @@
 
         // The target SDK of this client < Build.VERSION_CODES.S
         private boolean mIsPreSClient = false;
+        private final int mUid;
         // The flag of using java backend if the client's target SDK >= U
         private final boolean mUseJavaBackend;
         // Store client logs
         private final SharedLog mClientLogs;
 
-        private ClientInfo(INsdManagerCallback cb, boolean useJavaBackend, SharedLog sharedLog) {
+        private ClientInfo(INsdManagerCallback cb, int uid, boolean useJavaBackend,
+                SharedLog sharedLog) {
             mCb = cb;
+            mUid = uid;
             mUseJavaBackend = useJavaBackend;
             mClientLogs = sharedLog;
             mClientLogs.log("New client. useJavaBackend=" + useJavaBackend);
@@ -1903,6 +2080,8 @@
             StringBuilder sb = new StringBuilder();
             sb.append("mResolvedService ").append(mResolvedService).append("\n");
             sb.append("mIsLegacy ").append(mIsPreSClient).append("\n");
+            sb.append("mUseJavaBackend ").append(mUseJavaBackend).append("\n");
+            sb.append("mUid ").append(mUid).append("\n");
             for (int i = 0; i < mClientRequests.size(); i++) {
                 int clientID = mClientRequests.keyAt(i);
                 sb.append("clientId ")
@@ -1974,6 +2153,26 @@
                 }
             }
             mClientRequests.clear();
+            updateMulticastLock();
+        }
+
+        /**
+         * Returns true if this client has any Java backend request that requests one of the given
+         * networks.
+         */
+        boolean hasAnyJavaBackendRequestForNetworks(@NonNull ArraySet<Network> networks) {
+            for (int i = 0; i < mClientRequests.size(); i++) {
+                final ClientRequest req = mClientRequests.valueAt(i);
+                if (!(req instanceof JavaBackendClientRequest)) {
+                    continue;
+                }
+                final Network reqNetwork = ((JavaBackendClientRequest) mClientRequests.valueAt(i))
+                        .getRequestedNetwork();
+                if (MdnsUtils.isAnyNetworkMatched(reqNetwork, networks)) {
+                    return true;
+                }
+            }
+            return false;
         }
 
         // mClientRequests is a sparse array of listener id -> ClientRequest.  For a given
diff --git a/service-t/src/com/android/server/connectivity/mdns/MdnsSocketProvider.java b/service-t/src/com/android/server/connectivity/mdns/MdnsSocketProvider.java
index dc09bef..d90f67f 100644
--- a/service-t/src/com/android/server/connectivity/mdns/MdnsSocketProvider.java
+++ b/service-t/src/com/android/server/connectivity/mdns/MdnsSocketProvider.java
@@ -97,6 +97,8 @@
     // the netlink monitor is never stop and the old states must be kept.
     private final SparseArray<LinkProperties> mIfaceIdxToLinkProperties = new SparseArray<>();
     private final byte[] mPacketReadBuffer = new byte[READ_BUFFER_SIZE];
+    @NonNull
+    private final SocketRequestMonitor mSocketRequestMonitor;
     private boolean mMonitoringSockets = false;
     private boolean mRequestStop = false;
     private String mWifiP2pTetherInterface = null;
@@ -155,17 +157,20 @@
     }
 
     public MdnsSocketProvider(@NonNull Context context, @NonNull Looper looper,
-            @NonNull SharedLog sharedLog) {
-        this(context, looper, new Dependencies(), sharedLog);
+            @NonNull SharedLog sharedLog,
+            @NonNull SocketRequestMonitor socketRequestMonitor) {
+        this(context, looper, new Dependencies(), sharedLog, socketRequestMonitor);
     }
 
     MdnsSocketProvider(@NonNull Context context, @NonNull Looper looper,
-            @NonNull Dependencies deps, @NonNull SharedLog sharedLog) {
+            @NonNull Dependencies deps, @NonNull SharedLog sharedLog,
+            @NonNull SocketRequestMonitor socketRequestMonitor) {
         mContext = context;
         mLooper = looper;
         mHandler = new Handler(looper);
         mDependencies = deps;
         mSharedLog = sharedLog;
+        mSocketRequestMonitor = socketRequestMonitor;
         mNetworkCallback = new NetworkCallback() {
             @Override
             public void onLost(Network network) {
@@ -312,10 +317,12 @@
     private static class SocketInfo {
         final MdnsInterfaceSocket mSocket;
         final List<LinkAddress> mAddresses;
+        final int[] mTransports;
 
-        SocketInfo(MdnsInterfaceSocket socket, List<LinkAddress> addresses) {
+        SocketInfo(MdnsInterfaceSocket socket, List<LinkAddress> addresses, int[] transports) {
             mSocket = socket;
             mAddresses = new ArrayList<>(addresses);
+            mTransports = transports;
         }
     }
 
@@ -498,9 +505,13 @@
             if (networkKey == LOCAL_NET) {
                 transports = new int[0];
             } else {
-                transports = mActiveNetworksTransports.get(((NetworkAsKey) networkKey).mNetwork);
-                if (transports == null) {
+                final int[] knownTransports =
+                        mActiveNetworksTransports.get(((NetworkAsKey) networkKey).mNetwork);
+                if (knownTransports != null) {
+                    transports = knownTransports;
+                } else {
                     Log.wtf(TAG, "transports is missing for key: " + networkKey);
+                    transports = new int[0];
                 }
             }
             if (networkInterface == null || !isMdnsCapableInterface(networkInterface, transports)) {
@@ -512,21 +523,22 @@
                     networkInterface.getNetworkInterface(), MdnsConstants.MDNS_PORT, mLooper,
                     mPacketReadBuffer);
             final List<LinkAddress> addresses = lp.getLinkAddresses();
+            // TODO: technically transport types are mutable, although generally not in ways that
+            // would meaningfully impact the logic using it here. Consider updating logic to
+            // support transports being added/removed.
+            final SocketInfo socketInfo = new SocketInfo(socket, addresses, transports);
             if (networkKey == LOCAL_NET) {
-                mTetherInterfaceSockets.put(interfaceName, new SocketInfo(socket, addresses));
+                mTetherInterfaceSockets.put(interfaceName, socketInfo);
             } else {
-                mNetworkSockets.put(((NetworkAsKey) networkKey).mNetwork,
-                        new SocketInfo(socket, addresses));
+                mNetworkSockets.put(((NetworkAsKey) networkKey).mNetwork, socketInfo);
             }
             // Try to join IPv4/IPv6 group.
             socket.joinGroup(addresses);
 
             // Notify the listeners which need this socket.
-            if (networkKey == LOCAL_NET) {
-                notifySocketCreated(null /* network */, socket, addresses);
-            } else {
-                notifySocketCreated(((NetworkAsKey) networkKey).mNetwork, socket, addresses);
-            }
+            final Network network =
+                    networkKey == LOCAL_NET ? null : ((NetworkAsKey) networkKey).mNetwork;
+            notifySocketCreated(network, socketInfo);
         } catch (IOException e) {
             mSharedLog.e("Create socket failed ifName:" + interfaceName, e);
         }
@@ -568,6 +580,7 @@
 
         socketInfo.mSocket.destroy();
         notifyInterfaceDestroyed(network, socketInfo.mSocket);
+        mSocketRequestMonitor.onSocketDestroyed(network, socketInfo.mSocket);
         mSharedLog.log("Remove socket on net:" + network);
     }
 
@@ -576,15 +589,18 @@
         if (socketInfo == null) return;
         socketInfo.mSocket.destroy();
         notifyInterfaceDestroyed(null /* network */, socketInfo.mSocket);
+        mSocketRequestMonitor.onSocketDestroyed(null /* network */, socketInfo.mSocket);
         mSharedLog.log("Remove socket on ifName:" + interfaceName);
     }
 
-    private void notifySocketCreated(Network network, MdnsInterfaceSocket socket,
-            List<LinkAddress> addresses) {
+    private void notifySocketCreated(Network network, SocketInfo socketInfo) {
         for (int i = 0; i < mCallbacksToRequestedNetworks.size(); i++) {
             final Network requestedNetwork = mCallbacksToRequestedNetworks.valueAt(i);
             if (isNetworkMatched(requestedNetwork, network)) {
-                mCallbacksToRequestedNetworks.keyAt(i).onSocketCreated(network, socket, addresses);
+                mCallbacksToRequestedNetworks.keyAt(i).onSocketCreated(network, socketInfo.mSocket,
+                        socketInfo.mAddresses);
+                mSocketRequestMonitor.onSocketRequestFulfilled(network, socketInfo.mSocket,
+                        socketInfo.mTransports);
             }
         }
     }
@@ -622,6 +638,8 @@
         } else {
             // Notify the socket for requested network.
             cb.onSocketCreated(network, socketInfo.mSocket, socketInfo.mAddresses);
+            mSocketRequestMonitor.onSocketRequestFulfilled(network, socketInfo.mSocket,
+                    socketInfo.mTransports);
         }
     }
 
@@ -636,6 +654,8 @@
             // Notify the socket for requested network.
             cb.onSocketCreated(
                     null /* network */, socketInfo.mSocket, socketInfo.mAddresses);
+            mSocketRequestMonitor.onSocketRequestFulfilled(null /* socketNetwork */,
+                    socketInfo.mSocket, socketInfo.mTransports);
         }
     }
 
@@ -690,6 +710,7 @@
             if (matchRequestedNetwork(network)) continue;
             final SocketInfo info = mNetworkSockets.removeAt(i);
             info.mSocket.destroy();
+            mSocketRequestMonitor.onSocketDestroyed(network, info.mSocket);
             mSharedLog.log("Remove socket on net:" + network + " after unrequestSocket");
         }
 
@@ -699,6 +720,7 @@
         for (int i = mTetherInterfaceSockets.size() - 1; i >= 0; i--) {
             final SocketInfo info = mTetherInterfaceSockets.valueAt(i);
             info.mSocket.destroy();
+            mSocketRequestMonitor.onSocketDestroyed(null /* network */, info.mSocket);
             mSharedLog.log("Remove socket on ifName:" + mTetherInterfaceSockets.keyAt(i)
                     + " after unrequestSocket");
         }
@@ -709,19 +731,61 @@
     }
 
 
-    /*** Callbacks for listening socket changes */
+    /**
+     * Callback used to register socket requests.
+     */
     public interface SocketCallback {
-        /*** Notify the socket is created */
+        /**
+         * Notify the socket was created for the registered request.
+         *
+         * This may be called immediately when the request is registered with an existing socket,
+         * if it had been created previously for other requests.
+         */
         default void onSocketCreated(@Nullable Network network, @NonNull MdnsInterfaceSocket socket,
                 @NonNull List<LinkAddress> addresses) {}
-        /*** Notify the interface is destroyed */
+
+        /**
+         * Notify that the interface was destroyed, so the provided socket cannot be used anymore.
+         *
+         * This indicates that although the socket was still requested, it had to be destroyed.
+         */
         default void onInterfaceDestroyed(@Nullable Network network,
                 @NonNull MdnsInterfaceSocket socket) {}
-        /*** Notify the addresses is changed on the network */
+
+        /**
+         * Notify the interface addresses have changed for the network.
+         */
         default void onAddressesChanged(@Nullable Network network,
                 @NonNull MdnsInterfaceSocket socket, @NonNull List<LinkAddress> addresses) {}
     }
 
+    /**
+     * Global callback indicating when sockets are created or destroyed for requests.
+     */
+    public interface SocketRequestMonitor {
+        /**
+         * Indicates that the socket was used to fulfill the request of one requester.
+         *
+         * There is always at most one socket created for each interface. The interface is available
+         * in {@link MdnsInterfaceSocket#getInterface()}.
+         * @param socketNetwork The network of the socket interface, if any.
+         * @param socket The socket that was provided to a requester.
+         * @param transports Array of TRANSPORT_* from {@link NetworkCapabilities}. Empty if the
+         *                   interface is not part of a network with known transports.
+         */
+        default void onSocketRequestFulfilled(@Nullable Network socketNetwork,
+                @NonNull MdnsInterfaceSocket socket, @NonNull int[] transports) {}
+
+        /**
+         * Indicates that a previously created socket was destroyed.
+         *
+         * @param socketNetwork The network of the socket interface, if any.
+         * @param socket The destroyed socket.
+         */
+        default void onSocketDestroyed(@Nullable Network socketNetwork,
+                @NonNull MdnsInterfaceSocket socket) {}
+    }
+
     private interface NetworkKey {
     }
 
diff --git a/service-t/src/com/android/server/connectivity/mdns/util/MdnsUtils.java b/service-t/src/com/android/server/connectivity/mdns/util/MdnsUtils.java
index eb12b9a..3180a6f 100644
--- a/service-t/src/com/android/server/connectivity/mdns/util/MdnsUtils.java
+++ b/service-t/src/com/android/server/connectivity/mdns/util/MdnsUtils.java
@@ -20,6 +20,7 @@
 import android.annotation.Nullable;
 import android.net.Network;
 import android.os.Handler;
+import android.util.ArraySet;
 
 import com.android.server.connectivity.mdns.MdnsConstants;
 import com.android.server.connectivity.mdns.MdnsRecord;
@@ -129,12 +130,21 @@
         return false;
     }
 
-    /*** Check whether the target network is matched current network */
+    /*** Check whether the target network matches the current network */
     public static boolean isNetworkMatched(@Nullable Network targetNetwork,
             @Nullable Network currentNetwork) {
         return targetNetwork == null || targetNetwork.equals(currentNetwork);
     }
 
+    /*** Check whether the target network matches any of the current networks */
+    public static boolean isAnyNetworkMatched(@Nullable Network targetNetwork,
+            ArraySet<Network> currentNetworks) {
+        if (targetNetwork == null) {
+            return !currentNetworks.isEmpty();
+        }
+        return currentNetworks.contains(targetNetwork);
+    }
+
     /**
      * Truncate a service name to up to maxLength UTF-8 bytes.
      */