Don't allow BT contact connections during key agreement.

bramble-android/src/main/java/org/briarproject/bramble/plugin/bluetooth/AndroidBluetoothPlugin.java

@@ -55,10 +55,12 @@ class AndroidBluetoothPlugin extends BluetoothPlugin<BluetoothServerSocket> {
 	// Non-null if the plugin started successfully
 	private volatile BluetoothAdapter adapter = null;
 
-	AndroidBluetoothPlugin(Executor ioExecutor, AndroidExecutor androidExecutor,
+	AndroidBluetoothPlugin(BluetoothConnectionLimiter connectionLimiter,
+			Executor ioExecutor, AndroidExecutor androidExecutor,
 			Context appContext, SecureRandom secureRandom, Backoff backoff,
 			DuplexPluginCallback callback, int maxLatency) {
-		super(ioExecutor, secureRandom, backoff, callback, maxLatency);
+		super(connectionLimiter, ioExecutor, secureRandom, backoff, callback,
+				maxLatency);
 		this.androidExecutor = androidExecutor;
 		this.appContext = appContext;
 	}
@@ -154,7 +156,8 @@ class AndroidBluetoothPlugin extends BluetoothPlugin<BluetoothServerSocket> {
 	}
 
 	private DuplexTransportConnection wrapSocket(BluetoothSocket s) {
-		return new AndroidBluetoothTransportConnection(this, s);
+		return new AndroidBluetoothTransportConnection(this,
+				connectionLimiter, s);
 	}
 
 	@Override

bramble-android/src/main/java/org/briarproject/bramble/plugin/bluetooth/AndroidBluetoothPluginFactory.java

@@ -59,11 +59,13 @@ public class AndroidBluetoothPluginFactory implements DuplexPluginFactory {
 
 	@Override
 	public DuplexPlugin createPlugin(DuplexPluginCallback callback) {
+		BluetoothConnectionLimiter connectionLimiter =
+				new BluetoothConnectionLimiterImpl();
 		Backoff backoff = backoffFactory.createBackoff(MIN_POLLING_INTERVAL,
 				MAX_POLLING_INTERVAL, BACKOFF_BASE);
-		AndroidBluetoothPlugin plugin = new AndroidBluetoothPlugin(ioExecutor,
-				androidExecutor, appContext, secureRandom, backoff, callback,
-				MAX_LATENCY);
+		AndroidBluetoothPlugin plugin = new AndroidBluetoothPlugin(
+				connectionLimiter, ioExecutor, androidExecutor, appContext,
+				secureRandom, backoff, callback, MAX_LATENCY);
 		eventBus.addListener(plugin);
 		return plugin;
 	}

bramble-android/src/main/java/org/briarproject/bramble/plugin/bluetooth/AndroidBluetoothTransportConnection.java

@@ -14,10 +14,14 @@ import java.io.OutputStream;
 class AndroidBluetoothTransportConnection
 		extends AbstractDuplexTransportConnection {
 
+	private final BluetoothConnectionLimiter connectionManager;
 	private final BluetoothSocket socket;
 
-	AndroidBluetoothTransportConnection(Plugin plugin, BluetoothSocket socket) {
+	AndroidBluetoothTransportConnection(Plugin plugin,
+			BluetoothConnectionLimiter connectionManager,
+			BluetoothSocket socket) {
 		super(plugin);
+		this.connectionManager = connectionManager;
 		this.socket = socket;
 	}
 
@@ -33,6 +37,10 @@ class AndroidBluetoothTransportConnection
 
 	@Override
 	protected void closeConnection(boolean exception) throws IOException {
-		socket.close();
+		try {
+			socket.close();
+		} finally {
+			connectionManager.connectionClosed(this);
+		}
 	}
 }

bramble-api/src/main/java/org/briarproject/bramble/api/keyagreement/event/KeyAgreementStoppedListeningEvent.java

@@ -0,0 +1,9 @@
+package org.briarproject.bramble.api.keyagreement.event;
+
+import org.briarproject.bramble.api.event.Event;
+
+/**
+ * An event that is broadcast when a BQP task stops listening.
+ */
+public class KeyAgreementStoppedListeningEvent extends Event {
+}

bramble-core/src/main/java/org/briarproject/bramble/keyagreement/KeyAgreementTaskImpl.java

@@ -14,6 +14,7 @@ import org.briarproject.bramble.api.keyagreement.event.KeyAgreementFailedEvent;
 import org.briarproject.bramble.api.keyagreement.event.KeyAgreementFinishedEvent;
 import org.briarproject.bramble.api.keyagreement.event.KeyAgreementListeningEvent;
 import org.briarproject.bramble.api.keyagreement.event.KeyAgreementStartedEvent;
+import org.briarproject.bramble.api.keyagreement.event.KeyAgreementStoppedListeningEvent;
 import org.briarproject.bramble.api.keyagreement.event.KeyAgreementWaitingEvent;
 import org.briarproject.bramble.api.nullsafety.MethodsNotNullByDefault;
 import org.briarproject.bramble.api.nullsafety.ParametersNotNullByDefault;
@@ -71,6 +72,7 @@ class KeyAgreementTaskImpl extends Thread implements KeyAgreementTask,
 		if (localPayload != null) {
 			if (remotePayload == null) connector.stopListening();
 			else interrupt();
+			eventBus.broadcast(new KeyAgreementStoppedListeningEvent());
 		}
 	}
 

bramble-core/src/main/java/org/briarproject/bramble/plugin/bluetooth/BluetoothConnectionLimiter.java

@@ -0,0 +1,47 @@
+package org.briarproject.bramble.plugin.bluetooth;
+
+import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
+import org.briarproject.bramble.api.plugin.duplex.DuplexTransportConnection;
+
+@NotNullByDefault
+interface BluetoothConnectionLimiter {
+
+	/**
+	 * Informs the limiter that key agreement has started.
+	 */
+	void keyAgreementStarted();
+
+	/**
+	 * Informs the limiter that key agreement has ended.
+	 */
+	void keyAgreementEnded();
+
+	/**
+	 * Returns true if a contact connection can be opened. This method does not
+	 * need to be called for key agreement connections.
+	 */
+	boolean canOpenContactConnection();
+
+	/**
+	 * Informs the limiter that a contact connection has been opened. The
+	 * limiter may close the new connection if key agreement is in progress.
+	 * <p/>
+	 * Returns false if the limiter has closed the new connection.
+	 */
+	boolean contactConnectionOpened(DuplexTransportConnection conn);
+
+	/**
+	 * Informs the limiter that a key agreement connection has been opened.
+	 */
+	void keyAgreementConnectionOpened(DuplexTransportConnection conn);
+
+	/**
+	 * Informs the limiter that the given connection has been closed.
+	 */
+	void connectionClosed(DuplexTransportConnection conn);
+
+	/**
+	 * Informs the limiter that all connections have been closed.
+	 */
+	void allConnectionsClosed();
+}

bramble-core/src/main/java/org/briarproject/bramble/plugin/bluetooth/BluetoothConnectionLimiterImpl.java

@@ -0,0 +1,115 @@
+package org.briarproject.bramble.plugin.bluetooth;
+
+import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
+import org.briarproject.bramble.api.plugin.duplex.DuplexTransportConnection;
+
+import java.io.IOException;
+import java.util.ArrayList;
+import java.util.LinkedList;
+import java.util.List;
+import java.util.logging.Logger;
+
+import javax.annotation.concurrent.ThreadSafe;
+
+import static java.util.logging.Level.INFO;
+import static java.util.logging.Level.WARNING;
+
+@NotNullByDefault
+@ThreadSafe
+class BluetoothConnectionLimiterImpl implements BluetoothConnectionLimiter {
+
+	private static final Logger LOG =
+			Logger.getLogger(BluetoothConnectionLimiterImpl.class.getName());
+
+	private final Object lock = new Object();
+	// The following are locking: lock
+	private final LinkedList<DuplexTransportConnection> connections =
+			new LinkedList<>();
+	private boolean keyAgreementInProgress = false;
+
+	@Override
+	public void keyAgreementStarted() {
+		List<DuplexTransportConnection> close;
+		synchronized (lock) {
+			keyAgreementInProgress = true;
+			close = new ArrayList<>(connections);
+			connections.clear();
+		}
+		if (LOG.isLoggable(INFO)) {
+			LOG.info("Key agreement started, closing " + close.size() +
+					" connections");
+		}
+		for (DuplexTransportConnection conn : close) tryToClose(conn);
+	}
+
+	@Override
+	public void keyAgreementEnded() {
+		synchronized (lock) {
+			keyAgreementInProgress = false;
+		}
+		LOG.info("Key agreement ended");
+	}
+
+	@Override
+	public boolean canOpenContactConnection() {
+		synchronized (lock) {
+			if (keyAgreementInProgress) {
+				LOG.info("Can't open contact connection during key agreement");
+				return false;
+			} else {
+				LOG.info("Can open contact connection");
+				return true;
+			}
+		}
+	}
+
+	@Override
+	public boolean contactConnectionOpened(DuplexTransportConnection conn) {
+		boolean accept = true;
+		synchronized (lock) {
+			if (keyAgreementInProgress) {
+				LOG.info("Refusing contact connection during key agreement");
+				accept = false;
+			} else {
+				LOG.info("Accepting contact connection");
+				connections.add(conn);
+			}
+		}
+		if (!accept) tryToClose(conn);
+		return accept;
+	}
+
+	@Override
+	public void keyAgreementConnectionOpened(DuplexTransportConnection conn) {
+		synchronized (lock) {
+			LOG.info("Accepting key agreement connection");
+			connections.add(conn);
+		}
+	}
+
+	private void tryToClose(DuplexTransportConnection conn) {
+		try {
+			conn.getWriter().dispose(false);
+			conn.getReader().dispose(false, false);
+		} catch (IOException e) {
+			if (LOG.isLoggable(WARNING)) LOG.log(WARNING, e.toString(), e);
+		}
+	}
+
+	@Override
+	public void connectionClosed(DuplexTransportConnection conn) {
+		synchronized (lock) {
+			connections.remove(conn);
+			if (LOG.isLoggable(INFO))
+				LOG.info("Connection closed, " + connections.size() + " open");
+		}
+	}
+
+	@Override
+	public void allConnectionsClosed() {
+		synchronized (lock) {
+			connections.clear();
+			LOG.info("All connections closed");
+		}
+	}
+}

bramble-core/src/main/java/org/briarproject/bramble/plugin/bluetooth/BluetoothPlugin.java

@@ -7,6 +7,8 @@ import org.briarproject.bramble.api.event.Event;
 import org.briarproject.bramble.api.event.EventListener;
 import org.briarproject.bramble.api.keyagreement.KeyAgreementConnection;
 import org.briarproject.bramble.api.keyagreement.KeyAgreementListener;
+import org.briarproject.bramble.api.keyagreement.event.KeyAgreementListeningEvent;
+import org.briarproject.bramble.api.keyagreement.event.KeyAgreementStoppedListeningEvent;
 import org.briarproject.bramble.api.nullsafety.MethodsNotNullByDefault;
 import org.briarproject.bramble.api.nullsafety.ParametersNotNullByDefault;
 import org.briarproject.bramble.api.plugin.Backoff;
@@ -51,6 +53,8 @@ abstract class BluetoothPlugin<SS> implements DuplexPlugin, EventListener {
 	private static final Logger LOG =
 			Logger.getLogger(BluetoothPlugin.class.getName());
 
+	final BluetoothConnectionLimiter connectionLimiter;
+
 	private final Executor ioExecutor;
 	private final SecureRandom secureRandom;
 	private final Backoff backoff;
@@ -91,8 +95,10 @@ abstract class BluetoothPlugin<SS> implements DuplexPlugin, EventListener {
 	abstract DuplexTransportConnection connectTo(String address, String uuid)
 			throws IOException;
 
-	BluetoothPlugin(Executor ioExecutor, SecureRandom secureRandom,
+	BluetoothPlugin(BluetoothConnectionLimiter connectionLimiter,
+			Executor ioExecutor, SecureRandom secureRandom,
 			Backoff backoff, DuplexPluginCallback callback, int maxLatency) {
+		this.connectionLimiter = connectionLimiter;
 		this.ioExecutor = ioExecutor;
 		this.secureRandom = secureRandom;
 		this.backoff = backoff;
@@ -110,6 +116,7 @@ abstract class BluetoothPlugin<SS> implements DuplexPlugin, EventListener {
 	void onAdapterDisabled() {
 		LOG.info("Bluetooth disabled");
 		tryToClose(socket);
+		connectionLimiter.allConnectionsClosed();
 		callback.transportDisabled();
 	}
 
@@ -213,7 +220,8 @@ abstract class BluetoothPlugin<SS> implements DuplexPlugin, EventListener {
 				return;
 			}
 			backoff.reset();
-			callback.incomingConnectionCreated(conn);
+			if (connectionLimiter.contactConnectionOpened(conn))
+				callback.incomingConnectionCreated(conn);
 			if (!running) return;
 		}
 	}
@@ -257,10 +265,12 @@ abstract class BluetoothPlugin<SS> implements DuplexPlugin, EventListener {
 			if (StringUtils.isNullOrEmpty(uuid)) continue;
 			ioExecutor.execute(() -> {
 				if (!isRunning() || !shouldAllowContactConnections()) return;
+				if (!connectionLimiter.canOpenContactConnection()) return;
 				DuplexTransportConnection conn = connect(address, uuid);
 				if (conn != null) {
 					backoff.reset();
-					callback.outgoingConnectionCreated(c, conn);
+					if (connectionLimiter.contactConnectionOpened(conn))
+						callback.outgoingConnectionCreated(c, conn);
 				}
 			});
 		}
@@ -300,12 +310,16 @@ abstract class BluetoothPlugin<SS> implements DuplexPlugin, EventListener {
 	@Override
 	public DuplexTransportConnection createConnection(ContactId c) {
 		if (!isRunning() || !shouldAllowContactConnections()) return null;
+		if (!connectionLimiter.canOpenContactConnection()) return null;
 		TransportProperties p = callback.getRemoteProperties(c);
 		String address = p.get(PROP_ADDRESS);
 		if (StringUtils.isNullOrEmpty(address)) return null;
 		String uuid = p.get(PROP_UUID);
 		if (StringUtils.isNullOrEmpty(uuid)) return null;
-		return connect(address, uuid);
+		DuplexTransportConnection conn = connect(address, uuid);
+		if (conn == null) return null;
+		// TODO: Why don't we reset the backoff here?
+		return connectionLimiter.contactConnectionOpened(conn) ? conn : null;
 	}
 
 	@Override
@@ -355,7 +369,9 @@ abstract class BluetoothPlugin<SS> implements DuplexPlugin, EventListener {
 		String uuid = UUID.nameUUIDFromBytes(commitment).toString();
 		if (LOG.isLoggable(INFO))
 			LOG.info("Connecting to key agreement UUID " + uuid);
-		return connect(address, uuid);
+		DuplexTransportConnection conn = connect(address, uuid);
+		if (conn != null) connectionLimiter.keyAgreementConnectionOpened(conn);
+		return conn;
 	}
 
 	private String parseAddress(BdfList descriptor) throws FormatException {
@@ -376,6 +392,10 @@ abstract class BluetoothPlugin<SS> implements DuplexPlugin, EventListener {
 			SettingsUpdatedEvent s = (SettingsUpdatedEvent) e;
 			if (s.getNamespace().equals(ID.getString()))
 				ioExecutor.execute(this::onSettingsUpdated);
+		} else if (e instanceof KeyAgreementListeningEvent) {
+			ioExecutor.execute(connectionLimiter::keyAgreementStarted);
+		} else if (e instanceof KeyAgreementStoppedListeningEvent) {
+			ioExecutor.execute(connectionLimiter::keyAgreementEnded);
 		}
 	}
 
@@ -408,6 +428,7 @@ abstract class BluetoothPlugin<SS> implements DuplexPlugin, EventListener {
 		public KeyAgreementConnection accept() throws IOException {
 			DuplexTransportConnection conn = acceptConnection(ss);
 			if (LOG.isLoggable(INFO)) LOG.info(ID + ": Incoming connection");
+			connectionLimiter.keyAgreementConnectionOpened(conn);
 			return new KeyAgreementConnection(conn, ID);
 		}
 

bramble-j2se/src/main/java/org/briarproject/bramble/plugin/bluetooth/JavaBluetoothPlugin.java

@@ -31,9 +31,11 @@ class JavaBluetoothPlugin extends BluetoothPlugin<StreamConnectionNotifier> {
 	// Non-null if the plugin started successfully
 	private volatile LocalDevice localDevice = null;
 
-	JavaBluetoothPlugin(Executor ioExecutor, SecureRandom secureRandom,
+	JavaBluetoothPlugin(BluetoothConnectionLimiter connectionManager,
+			Executor ioExecutor, SecureRandom secureRandom,
 			Backoff backoff, DuplexPluginCallback callback, int maxLatency) {
-		super(ioExecutor, secureRandom, backoff, callback, maxLatency);
+		super(connectionManager, ioExecutor, secureRandom, backoff, callback,
+				maxLatency);
 	}
 
 	@Override
@@ -110,6 +112,6 @@ class JavaBluetoothPlugin extends BluetoothPlugin<StreamConnectionNotifier> {
 	}
 
 	private DuplexTransportConnection wrapSocket(StreamConnection s) {
-		return new JavaBluetoothTransportConnection(this, s);
+		return new JavaBluetoothTransportConnection(this, connectionLimiter, s);
 	}
 }

bramble-j2se/src/main/java/org/briarproject/bramble/plugin/bluetooth/JavaBluetoothPluginFactory.java

@@ -51,10 +51,12 @@ public class JavaBluetoothPluginFactory implements DuplexPluginFactory {
 
 	@Override
 	public DuplexPlugin createPlugin(DuplexPluginCallback callback) {
+		BluetoothConnectionLimiter connectionLimiter =
+				new BluetoothConnectionLimiterImpl();
 		Backoff backoff = backoffFactory.createBackoff(MIN_POLLING_INTERVAL,
 				MAX_POLLING_INTERVAL, BACKOFF_BASE);
-		JavaBluetoothPlugin plugin = new JavaBluetoothPlugin(ioExecutor,
-				secureRandom, backoff, callback, MAX_LATENCY);
+		JavaBluetoothPlugin plugin = new JavaBluetoothPlugin(connectionLimiter,
+				ioExecutor, secureRandom, backoff, callback, MAX_LATENCY);
 		eventBus.addListener(plugin);
 		return plugin;
 	}

bramble-j2se/src/main/java/org/briarproject/bramble/plugin/bluetooth/JavaBluetoothTransportConnection.java

@@ -14,11 +14,15 @@ import javax.microedition.io.StreamConnection;
 class JavaBluetoothTransportConnection
 		extends AbstractDuplexTransportConnection {
 
+	private final BluetoothConnectionLimiter connectionManager;
 	private final StreamConnection stream;
 
-	JavaBluetoothTransportConnection(Plugin plugin, StreamConnection stream) {
+	JavaBluetoothTransportConnection(Plugin plugin,
+			BluetoothConnectionLimiter connectionManager,
+			StreamConnection stream) {
 		super(plugin);
 		this.stream = stream;
+		this.connectionManager = connectionManager;
 	}
 
 	@Override
@@ -33,6 +37,10 @@ class JavaBluetoothTransportConnection
 
 	@Override
 	protected void closeConnection(boolean exception) throws IOException {
-		stream.close();
+		try {
+			stream.close();
+		} finally {
+			connectionManager.connectionClosed(this);
+		}
 	}
 }