NsdService does not clean up after exiting clients

When a client of the NsdService exits, NsdService should
clean up the requests it has sent to the mDNS daemon:
cancel any pending resource-discovery and resource-resolution
queries, and remove any services registered by this client.

If this isn't done, several bad things happen. The daemon will
continue to run unnecessarily, will report service discoveries
that can't be forwarded on to the client, and will continue to
advertise service ports for an application which is no longer
running until the device is rebooted (mDNS pollution).

Bug: 9801184
Change-Id: I0aa7311480322aefcff16f902fbbf34f50985d38

services/java/com/android/server/NsdService.java

@@ -152,25 +152,40 @@ public class NsdService extends INsdManager.Stub {
         class DefaultState extends State {
             @Override
             public boolean processMessage(Message msg) {
+                ClientInfo cInfo = null;
                 switch (msg.what) {
                     case AsyncChannel.CMD_CHANNEL_HALF_CONNECTED:
                         if (msg.arg1 == AsyncChannel.STATUS_SUCCESSFUL) {
                             AsyncChannel c = (AsyncChannel) msg.obj;
                             if (DBG) Slog.d(TAG, "New client listening to asynchronous messages");
                             c.sendMessage(AsyncChannel.CMD_CHANNEL_FULLY_CONNECTED);
-                            ClientInfo cInfo = new ClientInfo(c, msg.replyTo);
+                            cInfo = new ClientInfo(c, msg.replyTo);
                             mClients.put(msg.replyTo, cInfo);
                         } else {
                             Slog.e(TAG, "Client connection failure, error=" + msg.arg1);
                         }
                         break;
                     case AsyncChannel.CMD_CHANNEL_DISCONNECTED:
-                        if (msg.arg1 == AsyncChannel.STATUS_SEND_UNSUCCESSFUL) {
+                        switch (msg.arg1) {
-                            Slog.e(TAG, "Send failed, client connection lost");
+                            case AsyncChannel.STATUS_SEND_UNSUCCESSFUL:
-                        } else {
+                                Slog.e(TAG, "Send failed, client connection lost");
-                            if (DBG) Slog.d(TAG, "Client connection lost with reason: " + msg.arg1);
+                                break;
+                            case AsyncChannel.STATUS_REMOTE_DISCONNECTION:
+                                if (DBG) Slog.d(TAG, "Client disconnected");
+                                break;
+                            default:
+                                if (DBG) Slog.d(TAG, "Client connection lost with reason: " + msg.arg1);
+                                break;
+                        }
+                        cInfo = mClients.get(msg.replyTo);
+                        if (cInfo != null) {
+                            cInfo.expungeAllRequests();
+                            mClients.remove(msg.replyTo);
+                        }
+                        //Last client
+                        if (mClients.size() == 0) {
+                            stopMDnsDaemon();
                         }
-                        mClients.remove(msg.replyTo);
                         break;
                     case AsyncChannel.CMD_CHANNEL_FULL_CONNECTION:
                         AsyncChannel ac = new AsyncChannel();
@@ -248,13 +263,15 @@ public class NsdService extends INsdManager.Stub {
                 return false;
             }
 
-            private void storeRequestMap(int clientId, int globalId, ClientInfo clientInfo) {
+            private void storeRequestMap(int clientId, int globalId, ClientInfo clientInfo, int what) {
                 clientInfo.mClientIds.put(clientId, globalId);
+                clientInfo.mClientRequests.put(clientId, what);
                 mIdToClientInfoMap.put(globalId, clientInfo);
             }
 
             private void removeRequestMap(int clientId, int globalId, ClientInfo clientInfo) {
                 clientInfo.mClientIds.remove(clientId);
+                clientInfo.mClientRequests.remove(clientId);
                 mIdToClientInfoMap.remove(globalId);
             }
 
@@ -274,10 +291,6 @@ public class NsdService extends INsdManager.Stub {
                         result = NOT_HANDLED;
                         break;
                     case AsyncChannel.CMD_CHANNEL_DISCONNECTED:
-                        //Last client
-                        if (mClients.size() == 1) {
-                            stopMDnsDaemon();
-                        }
                         result = NOT_HANDLED;
                         break;
                     case NsdManager.DISABLE:
@@ -301,7 +314,7 @@ public class NsdService extends INsdManager.Stub {
                                 Slog.d(TAG, "Discover " + msg.arg2 + " " + id +
                                         servInfo.getServiceType());
                             }
-                            storeRequestMap(msg.arg2, id, clientInfo);
+                            storeRequestMap(msg.arg2, id, clientInfo, msg.what);
                             replyToMessage(msg, NsdManager.DISCOVER_SERVICES_STARTED, servInfo);
                         } else {
                             stopServiceDiscovery(id);
@@ -340,7 +353,7 @@ public class NsdService extends INsdManager.Stub {
                         id = getUniqueId();
                         if (registerService(id, (NsdServiceInfo) msg.obj)) {
                             if (DBG) Slog.d(TAG, "Register " + msg.arg2 + " " + id);
-                            storeRequestMap(msg.arg2, id, clientInfo);
+                            storeRequestMap(msg.arg2, id, clientInfo, msg.what);
                             // Return success after mDns reports success
                         } else {
                             unregisterService(id);
@@ -381,7 +394,7 @@ public class NsdService extends INsdManager.Stub {
                         id = getUniqueId();
                         if (resolveService(id, servInfo)) {
                             clientInfo.mResolvedService = new NsdServiceInfo();
-                            storeRequestMap(msg.arg2, id, clientInfo);
+                            storeRequestMap(msg.arg2, id, clientInfo, msg.what);
                         } else {
                             replyToMessage(msg, NsdManager.RESOLVE_SERVICE_FAILED,
                                     NsdManager.FAILURE_INTERNAL_ERROR);
@@ -487,7 +500,7 @@ public class NsdService extends INsdManager.Stub {
 
                         int id2 = getUniqueId();
                         if (getAddrInfo(id2, cooked[3])) {
-                            storeRequestMap(clientId, id2, clientInfo);
+                            storeRequestMap(clientId, id2, clientInfo, NsdManager.RESOLVE_SERVICE);
                         } else {
                             clientInfo.mChannel.sendMessage(NsdManager.RESOLVE_SERVICE_FAILED,
                                     NsdManager.FAILURE_INTERNAL_ERROR, clientId);
@@ -827,6 +840,9 @@ public class NsdService extends INsdManager.Stub {
         /* A map from client id to unique id sent to mDns */
         private SparseArray<Integer> mClientIds = new SparseArray<Integer>();
 
+        /* A map from client id to the type of the request we had received */
+        private SparseArray<Integer> mClientRequests = new SparseArray<Integer>();
+
         private ClientInfo(AsyncChannel c, Messenger m) {
             mChannel = c;
             mMessenger = m;
@@ -840,10 +856,41 @@ public class NsdService extends INsdManager.Stub {
             sb.append("mMessenger ").append(mMessenger).append("\n");
             sb.append("mResolvedService ").append(mResolvedService).append("\n");
             for(int i = 0; i< mClientIds.size(); i++) {
-                sb.append("clientId ").append(mClientIds.keyAt(i));
+                int clientID = mClientIds.keyAt(i);
-                sb.append(" mDnsId ").append(mClientIds.valueAt(i)).append("\n");
+                sb.append("clientId ").append(clientID).
+                    append(" mDnsId ").append(mClientIds.valueAt(i)).
+                    append(" type ").append(mClientRequests.get(clientID)).append("\n");
             }
             return sb.toString();
         }
+
+        // Remove any pending requests from the global map when we get rid of a client,
+        // and send cancellations to the daemon.
+        private void expungeAllRequests() {
+            int globalId, clientId, i;
+            for (i = 0; i < mClientIds.size(); i++) {
+                clientId = mClientIds.keyAt(i);
+                globalId = mClientIds.valueAt(i);
+                mIdToClientInfoMap.remove(globalId);
+                if (DBG) Slog.d(TAG, "Terminating client-ID " + clientId +
+                        " global-ID " + globalId + " type " + mClientRequests.get(clientId));
+                switch (mClientRequests.get(clientId)) {
+                    case NsdManager.DISCOVER_SERVICES:
+                        stopServiceDiscovery(globalId);
+                        break;
+                    case NsdManager.RESOLVE_SERVICE:
+                        stopResolveService(globalId);
+                        break;
+                    case NsdManager.REGISTER_SERVICE:
+                        unregisterService(globalId);
+                        break;
+                    default:
+                        break;
+                }
+            }
+            mClientIds.clear();
+            mClientRequests.clear();
+        }
+
     }
 }