LAN plugin should re-bind each time wifi becomes available. Bug #51.

briar-android/src/org/briarproject/plugins/AndroidPluginsModule.java

@@ -15,7 +15,7 @@ import org.briarproject.api.plugins.simplex.SimplexPluginConfig;
 import org.briarproject.api.plugins.simplex.SimplexPluginFactory;
 import org.briarproject.api.system.LocationUtils;
 import org.briarproject.plugins.droidtooth.DroidtoothPluginFactory;
-import org.briarproject.plugins.tcp.LanTcpPluginFactory;
+import org.briarproject.plugins.tcp.AndroidLanTcpPluginFactory;
 import org.briarproject.plugins.tor.TorPluginFactory;
 
 import android.app.Application;
@@ -44,14 +44,15 @@ public class AndroidPluginsModule extends AbstractModule {
 			CryptoComponent crypto, LocationUtils locationUtils,
 			ShutdownManager shutdownManager) {
 		Context appContext = app.getApplicationContext();
-		DuplexPluginFactory droidtooth = new DroidtoothPluginFactory(
+		DuplexPluginFactory bluetooth = new DroidtoothPluginFactory(
 				pluginExecutor, androidExecutor, appContext,
 				crypto.getSecureRandom());
 		DuplexPluginFactory tor = new TorPluginFactory(pluginExecutor,
 				appContext, locationUtils, shutdownManager);
-		DuplexPluginFactory lan = new LanTcpPluginFactory(pluginExecutor);
+		DuplexPluginFactory lan = new AndroidLanTcpPluginFactory(
+				pluginExecutor, appContext);
 		final Collection<DuplexPluginFactory> factories =
-				Arrays.asList(droidtooth, tor, lan);
+				Arrays.asList(bluetooth, tor, lan);
 		return new DuplexPluginConfig() {
 			public Collection<DuplexPluginFactory> getFactories() {
 				return factories;

briar-android/src/org/briarproject/plugins/tcp/AndroidLanTcpPlugin.java

+package org.briarproject.plugins.tcp;
+
+import static android.content.Context.CONNECTIVITY_SERVICE;
+import static android.net.ConnectivityManager.CONNECTIVITY_ACTION;
+import static android.net.ConnectivityManager.TYPE_WIFI;
+
+import java.util.concurrent.Executor;
+import java.util.logging.Logger;
+
+import org.briarproject.api.plugins.duplex.DuplexPluginCallback;
+
+import android.content.BroadcastReceiver;
+import android.content.Context;
+import android.content.Intent;
+import android.content.IntentFilter;
+import android.net.ConnectivityManager;
+import android.net.NetworkInfo;
+
+class AndroidLanTcpPlugin extends LanTcpPlugin {
+
+	private static final Logger LOG =
+			Logger.getLogger(AndroidLanTcpPlugin.class.getName());
+
+	private final Context appContext;
+
+	private volatile BroadcastReceiver networkStateReceiver = null;
+
+	AndroidLanTcpPlugin(Executor pluginExecutor, Context appContext,
+			DuplexPluginCallback callback, int maxFrameLength, long maxLatency,
+			long pollingInterval) {
+		super(pluginExecutor, callback, maxFrameLength, maxLatency,
+				pollingInterval);
+		this.appContext = appContext;
+	}
+
+	@Override
+	public boolean start() {
+		running = true;
+		// Register to receive network status events
+		networkStateReceiver = new NetworkStateReceiver();
+		IntentFilter filter = new IntentFilter(CONNECTIVITY_ACTION);
+		appContext.registerReceiver(networkStateReceiver, filter);
+		return true;
+	}
+
+	@Override
+	public void stop() {
+		running = false;
+		if(networkStateReceiver != null)
+			appContext.unregisterReceiver(networkStateReceiver);
+		tryToClose(socket);
+	}
+
+	private class NetworkStateReceiver extends BroadcastReceiver {
+
+		@Override
+		public void onReceive(Context ctx, Intent i) {
+			if(!running) return;
+			Object o = ctx.getSystemService(CONNECTIVITY_SERVICE);
+			ConnectivityManager cm = (ConnectivityManager) o;
+			NetworkInfo net = cm.getActiveNetworkInfo();
+			if(net != null && net.getType() == TYPE_WIFI && net.isConnected()) {
+				LOG.info("Connected to Wi-Fi");
+				if(socket == null || socket.isClosed()) bind();
+			} else {
+				LOG.info("Not connected to Wi-Fi");
+				tryToClose(socket);
+			}
+		}
+	}
+}

briar-android/src/org/briarproject/plugins/tcp/AndroidLanTcpPluginFactory.java

+package org.briarproject.plugins.tcp;
+
+import java.util.concurrent.Executor;
+
+import org.briarproject.api.TransportId;
+import org.briarproject.api.plugins.duplex.DuplexPlugin;
+import org.briarproject.api.plugins.duplex.DuplexPluginCallback;
+import org.briarproject.api.plugins.duplex.DuplexPluginFactory;
+
+import android.content.Context;
+
+public class AndroidLanTcpPluginFactory implements DuplexPluginFactory {
+
+	private static final int MAX_FRAME_LENGTH = 1024;
+	private static final long MAX_LATENCY = 60 * 1000; // 1 minute
+	private static final long POLLING_INTERVAL = 60 * 1000; // 1 minute
+
+	private final Executor pluginExecutor;
+	private final Context appContext;
+
+	public AndroidLanTcpPluginFactory(Executor pluginExecutor,
+			Context appContext) {
+		this.pluginExecutor = pluginExecutor;
+		this.appContext = appContext;
+	}
+
+	public TransportId getId() {
+		return LanTcpPlugin.ID;
+	}
+
+	public DuplexPlugin createPlugin(DuplexPluginCallback callback) {
+		return new AndroidLanTcpPlugin(pluginExecutor, appContext, callback,
+				MAX_FRAME_LENGTH, MAX_LATENCY, POLLING_INTERVAL);
+	}
+}

briar-core/src/org/briarproject/plugins/tcp/LanTcpPlugin.java

@@ -18,7 +18,6 @@ import org.briarproject.api.TransportId;
 import org.briarproject.api.TransportProperties;
 import org.briarproject.api.plugins.duplex.DuplexPluginCallback;
 
-/** A TCP plugin that supports exchanging invitations over a LAN. */
 class LanTcpPlugin extends TcpPlugin {
 
 	static final TransportId ID = new TransportId("lan");

briar-core/src/org/briarproject/plugins/tcp/TcpPlugin.java

@@ -38,7 +38,7 @@ abstract class TcpPlugin implements DuplexPlugin {
 	protected final long maxLatency, pollingInterval;
 
 	protected volatile boolean running = false;
-	private volatile ServerSocket socket = null;
+	protected volatile ServerSocket socket = null;
 
 	/**
 	 * Returns zero or more socket addresses on which the plugin should listen,
@@ -65,47 +65,47 @@ abstract class TcpPlugin implements DuplexPlugin {
 
 	public boolean start() {
 		running = true;
-		pluginExecutor.execute(new Runnable() {
-			public void run() {
-				bind();
-			}
-		});
+		bind();
 		return true;
 	}
 
-	private void bind() {
-		ServerSocket ss = null;
-		boolean found = false;
-		for(SocketAddress addr : getLocalSocketAddresses()) {
-			try {
-				ss = new ServerSocket();
-				ss.bind(addr);
-				found = true;
-				break;
-			} catch(IOException e) {
-				if(LOG.isLoggable(INFO)) LOG.info("Failed to bind " + addr);
-				tryToClose(ss);
-				continue;
+	protected void bind() {
+		pluginExecutor.execute(new Runnable() {
+			public void run() {
+				if(!running) return;
+				ServerSocket ss = null;
+				for(SocketAddress addr : getLocalSocketAddresses()) {
+					try {
+						ss = new ServerSocket();
+						ss.bind(addr);
+						break;
+					} catch(IOException e) {
+						if(LOG.isLoggable(INFO))
+							LOG.info("Failed to bind " + addr);
+						tryToClose(ss);
+						continue;
+					}
+				}
+				if(ss == null || !ss.isBound()) {
+					LOG.info("Could not bind server socket");
+					return;
+				}
+				if(!running) {
+					tryToClose(ss);
+					return;
+				}
+				socket = ss;
+				SocketAddress local = ss.getLocalSocketAddress();
+				setLocalSocketAddress((InetSocketAddress) local);
+				if(LOG.isLoggable(INFO)) LOG.info("Listening on " + local);
+				acceptContactConnections();
 			}
-		}
-		if(!found) {
-			LOG.info("Could not bind server socket");
-			return;
-		}
-		if(!running) {
-			tryToClose(ss);
-			return;
-		}
-		socket = ss;
-		if(LOG.isLoggable(INFO))
-			LOG.info("Listening on " + ss.getLocalSocketAddress());
-		setLocalSocketAddress((InetSocketAddress) ss.getLocalSocketAddress());
-		acceptContactConnections(ss);
+		});
 	}
 
 	protected void tryToClose(ServerSocket ss) {
 		try {
-			ss.close();
+			if(ss != null) ss.close();
 		} catch(IOException e) {
 			if(LOG.isLoggable(WARNING)) LOG.log(WARNING, e.toString(), e);
 		}
@@ -124,32 +124,31 @@ abstract class TcpPlugin implements DuplexPlugin {
 		callback.mergeLocalProperties(p);
 	}
 
-	private void acceptContactConnections(ServerSocket ss) {
-		while(true) {
+	private void acceptContactConnections() {
+		while(isRunning()) {
 			Socket s;
 			try {
-				s = ss.accept();
+				s = socket.accept();
 			} catch(IOException e) {
 				// This is expected when the socket is closed
 				if(LOG.isLoggable(INFO)) LOG.info(e.toString());
-				tryToClose(ss);
+				tryToClose(socket);
 				return;
 			}
 			if(LOG.isLoggable(INFO))
 				LOG.info("Connection from " + s.getRemoteSocketAddress());
 			TcpTransportConnection conn = new TcpTransportConnection(this, s);
 			callback.incomingConnectionCreated(conn);
-			if(!running) return;
 		}
 	}
 
 	public void stop() {
 		running = false;
-		if(socket != null) tryToClose(socket);
+		tryToClose(socket);
 	}
 
 	public boolean isRunning() {
-		return running && socket != null && socket.isBound();
+		return running && socket != null && !socket.isClosed();
 	}
 
 	public boolean shouldPoll() {
@@ -161,7 +160,7 @@ abstract class TcpPlugin implements DuplexPlugin {
 	}
 
 	public void poll(Collection<ContactId> connected) {
-		if(!running) return;
+		if(!isRunning()) return;
 		Map<ContactId, TransportProperties> remote =
 				callback.getRemoteProperties();
 		for(final ContactId c : remote.keySet()) {
@@ -180,7 +179,7 @@ abstract class TcpPlugin implements DuplexPlugin {
 	}
 
 	public DuplexTransportConnection createConnection(ContactId c) {
-		if(!running) return null;
+		if(!isRunning()) return null;
 		SocketAddress addr = getRemoteSocketAddress(c);
 		if(addr == null) return null;
 		Socket s = new Socket();