Merge "Only send to downstream ifaces for null network"
diff --git a/service-t/src/com/android/server/connectivity/mdns/EnqueueMdnsQueryCallable.java b/service-t/src/com/android/server/connectivity/mdns/EnqueueMdnsQueryCallable.java
index 9a67007..866ecba 100644
--- a/service-t/src/com/android/server/connectivity/mdns/EnqueueMdnsQueryCallable.java
+++ b/service-t/src/com/android/server/connectivity/mdns/EnqueueMdnsQueryCallable.java
@@ -211,7 +211,7 @@
                         | (expectUnicastResponse ? MdnsConstants.QCLASS_UNICAST : 0));
     }
 
-    private void sendPacketTo(MdnsSocketClientBase requestSender, InetSocketAddress address)
+    private void sendPacketTo(MdnsSocketClient requestSender, InetSocketAddress address)
             throws IOException {
         DatagramPacket packet = packetWriter.getPacket(address);
         if (expectUnicastResponse) {
diff --git a/service-t/src/com/android/server/connectivity/mdns/MdnsMultinetworkSocketClient.java b/service-t/src/com/android/server/connectivity/mdns/MdnsMultinetworkSocketClient.java
index 52c8622..d6f2d06 100644
--- a/service-t/src/com/android/server/connectivity/mdns/MdnsMultinetworkSocketClient.java
+++ b/service-t/src/com/android/server/connectivity/mdns/MdnsMultinetworkSocketClient.java
@@ -17,7 +17,6 @@
 package com.android.server.connectivity.mdns;
 
 import static com.android.server.connectivity.mdns.util.MdnsUtils.ensureRunningOnHandlerThread;
-import static com.android.server.connectivity.mdns.util.MdnsUtils.isNetworkMatched;
 
 import android.annotation.NonNull;
 import android.annotation.Nullable;
@@ -34,6 +33,7 @@
 import java.net.Inet6Address;
 import java.net.InetSocketAddress;
 import java.util.List;
+import java.util.Objects;
 
 /**
  * The {@link MdnsMultinetworkSocketClient} manages the multinetwork socket for mDns
@@ -216,7 +216,10 @@
             final Network network = activeSockets.valueAt(i);
             // Check ip capability and network before sending packet
             if (((isIpv6 && socket.hasJoinedIpv6()) || (isIpv4 && socket.hasJoinedIpv4()))
-                    && isNetworkMatched(targetNetwork, network)) {
+                    // Contrary to MdnsUtils.isNetworkMatched, only send packets targeting
+                    // the null network to interfaces that have the null network (tethering
+                    // downstream interfaces).
+                    && Objects.equals(network, targetNetwork)) {
                 try {
                     socket.send(packet);
                 } catch (IOException e) {
@@ -248,12 +251,6 @@
         }
     }
 
-    /** Sends a mDNS request packet that asks for multicast response. */
-    @Override
-    public void sendMulticastPacket(@NonNull DatagramPacket packet) {
-        sendMulticastPacket(packet, null /* network */);
-    }
-
     /**
      * Sends a mDNS request packet via given network that asks for multicast response. Null network
      * means sending packet via all networks.
@@ -263,12 +260,6 @@
         mHandler.post(() -> sendMdnsPacket(packet, network));
     }
 
-    /** Sends a mDNS request packet that asks for unicast response. */
-    @Override
-    public void sendUnicastPacket(@NonNull DatagramPacket packet) {
-        sendUnicastPacket(packet, null /* network */);
-    }
-
     /**
      * Sends a mDNS request packet via given network that asks for unicast response. Null network
      * means sending packet via all networks.
diff --git a/service-t/src/com/android/server/connectivity/mdns/MdnsSocketClient.java b/service-t/src/com/android/server/connectivity/mdns/MdnsSocketClient.java
index 783b18a..1144d16 100644
--- a/service-t/src/com/android/server/connectivity/mdns/MdnsSocketClient.java
+++ b/service-t/src/com/android/server/connectivity/mdns/MdnsSocketClient.java
@@ -195,13 +195,11 @@
     }
 
     /** Sends a mDNS request packet that asks for multicast response. */
-    @Override
     public void sendMulticastPacket(@NonNull DatagramPacket packet) {
         sendMdnsPacket(packet, multicastPacketQueue);
     }
 
     /** Sends a mDNS request packet that asks for unicast response. */
-    @Override
     public void sendUnicastPacket(DatagramPacket packet) {
         if (useSeparateSocketForUnicast) {
             sendMdnsPacket(packet, unicastPacketQueue);
@@ -210,6 +208,36 @@
         }
     }
 
+    @Override
+    public void sendMulticastPacket(@NonNull DatagramPacket packet, @Nullable Network network) {
+        if (network != null) {
+            throw new IllegalArgumentException("This socket client does not support sending to "
+                    + "specific networks");
+        }
+        sendMulticastPacket(packet);
+    }
+
+    @Override
+    public void sendUnicastPacket(@NonNull DatagramPacket packet, @Nullable Network network) {
+        if (network != null) {
+            throw new IllegalArgumentException("This socket client does not support sending to "
+                    + "specific networks");
+        }
+        sendUnicastPacket(packet);
+    }
+
+    @Override
+    public void notifyNetworkRequested(
+            @NonNull MdnsServiceBrowserListener listener,
+            @Nullable Network network,
+            @NonNull SocketCreationCallback socketCreationCallback) {
+        if (network != null) {
+            throw new IllegalArgumentException("This socket client does not support requesting "
+                    + "specific networks");
+        }
+        socketCreationCallback.onSocketCreated(null);
+    }
+
     private void sendMdnsPacket(DatagramPacket packet, Queue<DatagramPacket> packetQueueToUse) {
         if (shouldStopSocketLoop && !MdnsConfigs.allowAddMdnsPacketAfterDiscoveryStops()) {
             LOGGER.w("sendMdnsPacket() is called after discovery already stopped");
diff --git a/service-t/src/com/android/server/connectivity/mdns/MdnsSocketClientBase.java b/service-t/src/com/android/server/connectivity/mdns/MdnsSocketClientBase.java
index c614cd3..22cf326 100644
--- a/service-t/src/com/android/server/connectivity/mdns/MdnsSocketClientBase.java
+++ b/service-t/src/com/android/server/connectivity/mdns/MdnsSocketClientBase.java
@@ -38,35 +38,25 @@
     /*** Set callback for receiving mDns response */
     void setCallback(@Nullable Callback callback);
 
-    /*** Sends a mDNS request packet that asks for multicast response. */
-    void sendMulticastPacket(@NonNull DatagramPacket packet);
+    /**
+     * Send a mDNS request packet via given network that asks for multicast response.
+     *
+     * <p>The socket client may use a null network to identify some or all interfaces, in which case
+     * passing null sends the packet to these.
+     */
+    void sendMulticastPacket(@NonNull DatagramPacket packet, @Nullable Network network);
 
     /**
-     * Sends a mDNS request packet via given network that asks for multicast response. Null network
-     * means sending packet via all networks.
+     * Send a mDNS request packet via given network that asks for unicast response.
+     *
+     * <p>The socket client may use a null network to identify some or all interfaces, in which case
+     * passing null sends the packet to these.
      */
-    default void sendMulticastPacket(@NonNull DatagramPacket packet, @Nullable Network network) {
-        throw new UnsupportedOperationException(
-                "This socket client doesn't support per-network sending");
-    }
-
-    /*** Sends a mDNS request packet that asks for unicast response. */
-    void sendUnicastPacket(@NonNull DatagramPacket packet);
-
-    /**
-     * Sends a mDNS request packet via given network that asks for unicast response. Null network
-     * means sending packet via all networks.
-     */
-    default void sendUnicastPacket(@NonNull DatagramPacket packet, @Nullable Network network) {
-        throw new UnsupportedOperationException(
-                "This socket client doesn't support per-network sending");
-    }
+    void sendUnicastPacket(@NonNull DatagramPacket packet, @Nullable Network network);
 
     /*** Notify that the given network is requested for mdns discovery / resolution */
-    default void notifyNetworkRequested(@NonNull MdnsServiceBrowserListener listener,
-            @Nullable Network network, @NonNull SocketCreationCallback socketCreationCallback) {
-        socketCreationCallback.onSocketCreated(network);
-    }
+    void notifyNetworkRequested(@NonNull MdnsServiceBrowserListener listener,
+            @Nullable Network network, @NonNull SocketCreationCallback socketCreationCallback);
 
     /*** Notify that the network is unrequested */
     default void notifyNetworkUnrequested(@NonNull MdnsServiceBrowserListener listener) { }
diff --git a/tests/unit/java/com/android/server/connectivity/mdns/MdnsMultinetworkSocketClientTest.java b/tests/unit/java/com/android/server/connectivity/mdns/MdnsMultinetworkSocketClientTest.java
index c6137c6..87ba5d7 100644
--- a/tests/unit/java/com/android/server/connectivity/mdns/MdnsMultinetworkSocketClientTest.java
+++ b/tests/unit/java/com/android/server/connectivity/mdns/MdnsMultinetworkSocketClientTest.java
@@ -38,6 +38,7 @@
 import android.os.HandlerThread;
 
 import com.android.net.module.util.HexDump;
+import com.android.server.connectivity.mdns.MdnsSocketClientBase.SocketCreationCallback;
 import com.android.testutils.DevSdkIgnoreRule;
 import com.android.testutils.DevSdkIgnoreRunner;
 import com.android.testutils.HandlerUtils;
@@ -66,7 +67,7 @@
     @Mock private MdnsInterfaceSocket mSocket;
     @Mock private MdnsServiceBrowserListener mListener;
     @Mock private MdnsSocketClientBase.Callback mCallback;
-    @Mock private MdnsSocketClientBase.SocketCreationCallback mSocketCreationCallback;
+    @Mock private SocketCreationCallback mSocketCreationCallback;
     private MdnsMultinetworkSocketClient mSocketClient;
     private Handler mHandler;
 
@@ -113,22 +114,36 @@
                 InetAddresses.parseNumericAddress("192.0.2.1"), 0 /* port */);
         final DatagramPacket ipv6Packet = new DatagramPacket(BUFFER, 0 /* offset */, BUFFER.length,
                 InetAddresses.parseNumericAddress("2001:db8::"), 0 /* port */);
-        doReturn(true).when(mSocket).hasJoinedIpv4();
-        doReturn(true).when(mSocket).hasJoinedIpv6();
-        doReturn(createEmptyNetworkInterface()).when(mSocket).getInterface();
+
+        final MdnsInterfaceSocket tetherIfaceSock1 = mock(MdnsInterfaceSocket.class);
+        final MdnsInterfaceSocket tetherIfaceSock2 = mock(MdnsInterfaceSocket.class);
+        for (MdnsInterfaceSocket socket : List.of(mSocket, tetherIfaceSock1, tetherIfaceSock2)) {
+            doReturn(true).when(socket).hasJoinedIpv4();
+            doReturn(true).when(socket).hasJoinedIpv6();
+            doReturn(createEmptyNetworkInterface()).when(socket).getInterface();
+        }
+
         // Notify socket created
         callback.onSocketCreated(mNetwork, mSocket, List.of());
         verify(mSocketCreationCallback).onSocketCreated(mNetwork);
+        callback.onSocketCreated(null, tetherIfaceSock1, List.of());
+        verify(mSocketCreationCallback).onSocketCreated(null);
+        callback.onSocketCreated(null, tetherIfaceSock2, List.of());
+        verify(mSocketCreationCallback, times(2)).onSocketCreated(null);
 
         // Send packet to IPv4 with target network and verify sending has been called.
         mSocketClient.sendMulticastPacket(ipv4Packet, mNetwork);
         HandlerUtils.waitForIdle(mHandler, DEFAULT_TIMEOUT);
         verify(mSocket).send(ipv4Packet);
+        verify(tetherIfaceSock1, never()).send(any());
+        verify(tetherIfaceSock2, never()).send(any());
 
         // Send packet to IPv6 without target network and verify sending has been called.
-        mSocketClient.sendMulticastPacket(ipv6Packet);
+        mSocketClient.sendMulticastPacket(ipv6Packet, null);
         HandlerUtils.waitForIdle(mHandler, DEFAULT_TIMEOUT);
-        verify(mSocket).send(ipv6Packet);
+        verify(mSocket, never()).send(ipv6Packet);
+        verify(tetherIfaceSock1).send(ipv6Packet);
+        verify(tetherIfaceSock2).send(ipv6Packet);
     }
 
     @Test
@@ -181,61 +196,86 @@
 
     @Test
     public void testSocketRemovedAfterNetworkUnrequested() throws IOException {
-        // Request a socket
-        final SocketCallback callback = expectSocketCallback(mListener, mNetwork);
+        // Request sockets on all networks
+        final SocketCallback callback = expectSocketCallback(mListener, null);
         final DatagramPacket ipv4Packet = new DatagramPacket(BUFFER, 0 /* offset */, BUFFER.length,
                 InetAddresses.parseNumericAddress("192.0.2.1"), 0 /* port */);
+
+        // Notify 3 socket created, including 2 tethered interfaces (null network)
+        final MdnsInterfaceSocket socket2 = mock(MdnsInterfaceSocket.class);
+        final MdnsInterfaceSocket socket3 = mock(MdnsInterfaceSocket.class);
         doReturn(true).when(mSocket).hasJoinedIpv4();
         doReturn(true).when(mSocket).hasJoinedIpv6();
-        doReturn(createEmptyNetworkInterface()).when(mSocket).getInterface();
-        // Notify socket created
-        callback.onSocketCreated(mNetwork, mSocket, List.of());
-        verify(mSocketCreationCallback).onSocketCreated(mNetwork);
-
-        // Send IPv4 packet and verify sending has been called.
-        mSocketClient.sendMulticastPacket(ipv4Packet);
-        HandlerUtils.waitForIdle(mHandler, DEFAULT_TIMEOUT);
-        verify(mSocket).send(ipv4Packet);
-
-        // Request another socket with null network
-        final MdnsServiceBrowserListener listener2 = mock(MdnsServiceBrowserListener.class);
-        final Network network2 = mock(Network.class);
-        final MdnsInterfaceSocket socket2 = mock(MdnsInterfaceSocket.class);
-        final SocketCallback callback2 = expectSocketCallback(listener2, null);
         doReturn(true).when(socket2).hasJoinedIpv4();
         doReturn(true).when(socket2).hasJoinedIpv6();
+        doReturn(true).when(socket3).hasJoinedIpv4();
+        doReturn(true).when(socket3).hasJoinedIpv6();
+        doReturn(createEmptyNetworkInterface()).when(mSocket).getInterface();
         doReturn(createEmptyNetworkInterface()).when(socket2).getInterface();
-        // Notify socket created for two networks.
-        callback2.onSocketCreated(mNetwork, mSocket, List.of());
-        callback2.onSocketCreated(network2, socket2, List.of());
-        verify(mSocketCreationCallback, times(2)).onSocketCreated(mNetwork);
-        verify(mSocketCreationCallback).onSocketCreated(network2);
+        doReturn(createEmptyNetworkInterface()).when(socket3).getInterface();
 
-        // Send IPv4 packet and verify sending to two sockets.
-        mSocketClient.sendMulticastPacket(ipv4Packet);
+        callback.onSocketCreated(mNetwork, mSocket, List.of());
+        callback.onSocketCreated(null, socket2, List.of());
+        callback.onSocketCreated(null, socket3, List.of());
+        verify(mSocketCreationCallback).onSocketCreated(mNetwork);
+        verify(mSocketCreationCallback, times(2)).onSocketCreated(null);
+
+        // Send IPv4 packet on the non-null Network and verify sending has been called.
+        mSocketClient.sendMulticastPacket(ipv4Packet, mNetwork);
         HandlerUtils.waitForIdle(mHandler, DEFAULT_TIMEOUT);
-        verify(mSocket, times(2)).send(ipv4Packet);
-        verify(socket2).send(ipv4Packet);
+        verify(mSocket).send(ipv4Packet);
+        verify(socket2, never()).send(any());
+        verify(socket3, never()).send(any());
 
-        // Unrequest another socket
+        // Request another socket with null network, get the same interfaces
+        final SocketCreationCallback socketCreationCb2 = mock(SocketCreationCallback.class);
+        final MdnsServiceBrowserListener listener2 = mock(MdnsServiceBrowserListener.class);
+
+        // requestSocket is called a second time
+        final ArgumentCaptor<SocketCallback> callback2Captor =
+                ArgumentCaptor.forClass(SocketCallback.class);
+        mHandler.post(() -> mSocketClient.notifyNetworkRequested(
+                listener2, null, socketCreationCb2));
+        HandlerUtils.waitForIdle(mHandler, DEFAULT_TIMEOUT);
+        verify(mProvider, times(2)).requestSocket(eq(null), callback2Captor.capture());
+        final SocketCallback callback2 = callback2Captor.getAllValues().get(1);
+
+        // Notify socket created for all networks.
+        callback2.onSocketCreated(mNetwork, mSocket, List.of());
+        callback2.onSocketCreated(null, socket2, List.of());
+        callback2.onSocketCreated(null, socket3, List.of());
+        verify(socketCreationCb2).onSocketCreated(mNetwork);
+        verify(socketCreationCb2, times(2)).onSocketCreated(null);
+
+        // Send IPv4 packet to null network and verify sending to the 2 tethered interface sockets.
+        mSocketClient.sendMulticastPacket(ipv4Packet, null);
+        HandlerUtils.waitForIdle(mHandler, DEFAULT_TIMEOUT);
+        // ipv4Packet still sent only once on mSocket: times(1) matches the packet sent earlier on
+        // mNetwork
+        verify(mSocket, times(1)).send(ipv4Packet);
+        verify(socket2).send(ipv4Packet);
+        verify(socket3).send(ipv4Packet);
+
+        // Unregister the second request
         mHandler.post(() -> mSocketClient.notifyNetworkUnrequested(listener2));
         verify(mProvider, timeout(DEFAULT_TIMEOUT)).unrequestSocket(callback2);
 
-        // Send IPv4 packet again and verify only sending via mSocket
-        mSocketClient.sendMulticastPacket(ipv4Packet);
+        // Send IPv4 packet again and verify it's still sent a second time
+        mSocketClient.sendMulticastPacket(ipv4Packet, null);
         HandlerUtils.waitForIdle(mHandler, DEFAULT_TIMEOUT);
-        verify(mSocket, times(3)).send(ipv4Packet);
-        verify(socket2).send(ipv4Packet);
+        verify(socket2, times(2)).send(ipv4Packet);
+        verify(socket3, times(2)).send(ipv4Packet);
 
-        // Unrequest remaining socket
+        // Unrequest remaining sockets
         mHandler.post(() -> mSocketClient.notifyNetworkUnrequested(mListener));
         verify(mProvider, timeout(DEFAULT_TIMEOUT)).unrequestSocket(callback);
 
         // Send IPv4 packet and verify no more sending.
-        mSocketClient.sendMulticastPacket(ipv4Packet);
+        mSocketClient.sendMulticastPacket(ipv4Packet, null);
         HandlerUtils.waitForIdle(mHandler, DEFAULT_TIMEOUT);
-        verify(mSocket, times(3)).send(ipv4Packet);
-        verify(socket2).send(ipv4Packet);
+        verify(mSocket, times(1)).send(ipv4Packet);
+        verify(socket2, times(2)).send(ipv4Packet);
+        verify(socket3, times(2)).send(ipv4Packet);
     }
 
     @Test