Don't treat an incoming connection as an attempt to raise the limit.

Detect and close dead Bluetooth connections

See merge request briar/briar!1246

bramble-android/build.gradle

@@ -11,8 +11,8 @@ android {
 	defaultConfig {
 		minSdkVersion 16
 		targetSdkVersion 28
-		versionCode 10205
-		versionName "1.2.5"
+		versionCode 10207
+		versionName "1.2.7"
 		consumerProguardFiles 'proguard-rules.txt'
 
 		testInstrumentationRunner "androidx.test.runner.AndroidJUnitRunner"
@@ -38,7 +38,7 @@ configurations {
 
 dependencies {
 	implementation project(path: ':bramble-core', configuration: 'default')
-	tor 'org.briarproject:tor-android:0.3.5.9@zip'
+	tor 'org.briarproject:tor-android:0.3.5.10@zip'
 	tor 'org.briarproject:obfs4proxy-android:0.0.11-2@zip'
 
 	annotationProcessor 'com.google.dagger:dagger-compiler:2.24'

bramble-android/src/main/java/org/briarproject/bramble/account/AndroidAccountManager.java

@@ -12,6 +12,7 @@ import org.briarproject.bramble.api.identity.IdentityManager;
 
 import java.io.File;
 import java.util.HashSet;
+import java.util.List;
 import java.util.Set;
 import java.util.logging.Logger;
 
@@ -20,6 +21,7 @@ import javax.annotation.concurrent.GuardedBy;
 import javax.inject.Inject;
 
 import static android.os.Build.VERSION.SDK_INT;
+import static java.util.Arrays.asList;
 import static java.util.logging.Level.INFO;
 import static org.briarproject.bramble.util.IoUtils.deleteFileOrDir;
 import static org.briarproject.bramble.util.LogUtils.logFileOrDir;
@@ -30,6 +32,12 @@ class AndroidAccountManager extends AccountManagerImpl
 	private static final Logger LOG =
 			Logger.getLogger(AndroidAccountManager.class.getName());
 
+	/**
+	 * Directories that shouldn't be deleted when deleting the user's account.
+	 */
+	private static final List<String> PROTECTED_DIR_NAMES =
+			asList("cache", "code_cache", "lib", "shared_prefs");
+
 	protected final Context appContext;
 	private final SharedPreferences prefs;
 
@@ -81,7 +89,7 @@ class AndroidAccountManager extends AccountManagerImpl
 			if (!prefs.edit().clear().commit())
 				LOG.warning("Could not clear shared preferences");
 		}
-		// Delete files, except lib and shared_prefs directories
+		// Delete files, except protected directories
 		Set<File> files = new HashSet<>();
 		File dataDir = getDataDir();
 		@Nullable
@@ -90,14 +98,12 @@ class AndroidAccountManager extends AccountManagerImpl
 			LOG.warning("Could not list files in app data dir");
 		} else {
 			for (File file : fileArray) {
-				String name = file.getName();
-				if (!name.equals("lib") && !name.equals("shared_prefs")) {
+				if (!PROTECTED_DIR_NAMES.contains(file.getName())) {
 					files.add(file);
 				}
 			}
 		}
 		files.add(appContext.getFilesDir());
-		files.add(appContext.getCacheDir());
 		addIfNotNull(files, appContext.getExternalCacheDir());
 		if (SDK_INT >= 19) {
 			for (File file : appContext.getExternalCacheDirs()) {
@@ -109,12 +115,16 @@ class AndroidAccountManager extends AccountManagerImpl
 				addIfNotNull(files, file);
 			}
 		}
+		// Clear the cache directory but don't delete it
+		File cacheDir = appContext.getCacheDir();
+		File[] children = cacheDir.listFiles();
+		if (children != null) files.addAll(asList(children));
 		for (File file : files) {
+			if (LOG.isLoggable(INFO)) {
+				LOG.info("Deleting " + file.getAbsolutePath());
+			}
 			deleteFileOrDir(file);
 		}
-		// Recreate the cache dir as some OpenGL drivers expect it to exist
-		if (!new File(dataDir, "cache").mkdirs())
-			LOG.warning("Could not recreate cache dir");
 	}
 
 	private File getDataDir() {

bramble-android/src/main/java/org/briarproject/bramble/network/AndroidNetworkManager.java

@@ -32,6 +32,7 @@ import static android.content.Intent.ACTION_SCREEN_OFF;
 import static android.content.Intent.ACTION_SCREEN_ON;
 import static android.net.ConnectivityManager.CONNECTIVITY_ACTION;
 import static android.net.ConnectivityManager.TYPE_WIFI;
+import static android.net.wifi.p2p.WifiP2pManager.WIFI_P2P_THIS_DEVICE_CHANGED_ACTION;
 import static android.os.Build.VERSION.SDK_INT;
 import static android.os.PowerManager.ACTION_DEVICE_IDLE_MODE_CHANGED;
 import static java.util.concurrent.TimeUnit.MINUTES;
@@ -76,9 +77,9 @@ class AndroidNetworkManager implements NetworkManager, Service {
 		filter.addAction(ACTION_SCREEN_ON);
 		filter.addAction(ACTION_SCREEN_OFF);
 		filter.addAction(WIFI_AP_STATE_CHANGED_ACTION);
+		filter.addAction(WIFI_P2P_THIS_DEVICE_CHANGED_ACTION);
 		if (SDK_INT >= 23) filter.addAction(ACTION_DEVICE_IDLE_MODE_CHANGED);
 		appContext.registerReceiver(networkStateReceiver, filter);
-
 	}
 
 	@Override
@@ -136,7 +137,8 @@ class AndroidNetworkManager implements NetworkManager, Service {
 		}
 
 		private boolean isApEvent(@Nullable String action) {
-			return WIFI_AP_STATE_CHANGED_ACTION.equals(action);
+			return WIFI_AP_STATE_CHANGED_ACTION.equals(action) ||
+					WIFI_P2P_THIS_DEVICE_CHANGED_ACTION.equals(action);
 		}
 	}
 }

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

@@ -9,6 +9,7 @@ import android.content.Context;
 import android.content.Intent;
 import android.content.IntentFilter;
 
+import org.briarproject.bramble.api.io.TimeoutMonitor;
 import org.briarproject.bramble.api.nullsafety.MethodsNotNullByDefault;
 import org.briarproject.bramble.api.nullsafety.ParametersNotNullByDefault;
 import org.briarproject.bramble.api.plugin.Backoff;
@@ -24,7 +25,6 @@ import java.io.IOException;
 import java.security.SecureRandom;
 import java.util.ArrayList;
 import java.util.Collection;
-import java.util.Collections;
 import java.util.List;
 import java.util.UUID;
 import java.util.concurrent.BlockingQueue;
@@ -47,7 +47,10 @@ import static android.bluetooth.BluetoothAdapter.SCAN_MODE_NONE;
 import static android.bluetooth.BluetoothAdapter.STATE_OFF;
 import static android.bluetooth.BluetoothAdapter.STATE_ON;
 import static android.bluetooth.BluetoothDevice.ACTION_FOUND;
+import static android.bluetooth.BluetoothDevice.DEVICE_TYPE_LE;
 import static android.bluetooth.BluetoothDevice.EXTRA_DEVICE;
+import static android.os.Build.VERSION.SDK_INT;
+import static java.util.Collections.shuffle;
 import static java.util.concurrent.TimeUnit.MILLISECONDS;
 import static java.util.logging.Level.INFO;
 import static java.util.logging.Level.WARNING;
@@ -74,11 +77,12 @@ class AndroidBluetoothPlugin extends BluetoothPlugin<BluetoothServerSocket> {
 	private volatile BluetoothAdapter adapter = null;
 
 	AndroidBluetoothPlugin(BluetoothConnectionLimiter connectionLimiter,
-			Executor ioExecutor, AndroidExecutor androidExecutor,
-			Context appContext, SecureRandom secureRandom, Clock clock,
-			Backoff backoff, PluginCallback callback, int maxLatency) {
-		super(connectionLimiter, ioExecutor, secureRandom, backoff, callback,
-				maxLatency);
+			TimeoutMonitor timeoutMonitor, Executor ioExecutor,
+			SecureRandom secureRandom, AndroidExecutor androidExecutor,
+			Context appContext, Clock clock, Backoff backoff,
+			PluginCallback callback, int maxLatency, int maxIdleTime) {
+		super(connectionLimiter, timeoutMonitor, ioExecutor, secureRandom,
+				backoff, callback, maxLatency, maxIdleTime);
 		this.androidExecutor = androidExecutor;
 		this.appContext = appContext;
 		this.clock = clock;
@@ -146,12 +150,6 @@ class AndroidBluetoothPlugin extends BluetoothPlugin<BluetoothServerSocket> {
 		wasEnabledByUs = true;
 	}
 
-	@Override
-	void onAdapterDisabled() {
-		super.onAdapterDisabled();
-		wasEnabledByUs = false;
-	}
-
 	@Override
 	@Nullable
 	String getBluetoothAddress() {
@@ -176,9 +174,10 @@ class AndroidBluetoothPlugin extends BluetoothPlugin<BluetoothServerSocket> {
 		return wrapSocket(ss.accept());
 	}
 
-	private DuplexTransportConnection wrapSocket(BluetoothSocket s) {
-		return new AndroidBluetoothTransportConnection(this,
-				connectionLimiter, s);
+	private DuplexTransportConnection wrapSocket(BluetoothSocket s)
+			throws IOException {
+		return new AndroidBluetoothTransportConnection(this, connectionLimiter,
+				timeoutMonitor, s);
 	}
 
 	@Override
@@ -246,11 +245,15 @@ class AndroidBluetoothPlugin extends BluetoothPlugin<BluetoothServerSocket> {
 						break;
 					} else if (ACTION_FOUND.equals(action)) {
 						BluetoothDevice d = i.getParcelableExtra(EXTRA_DEVICE);
-						String address = d.getAddress();
-						if (LOG.isLoggable(INFO))
-							LOG.info("Discovered " + scrubMacAddress(address));
-						if (!addresses.contains(address))
-							addresses.add(address);
+						// Ignore Bluetooth LE devices
+						if (SDK_INT < 18 || d.getType() != DEVICE_TYPE_LE) {
+							String address = d.getAddress();
+							if (LOG.isLoggable(INFO))
+								LOG.info("Discovered " +
+										scrubMacAddress(address));
+							if (!addresses.contains(address))
+								addresses.add(address);
+						}
 					}
 					now = clock.currentTimeMillis();
 				}
@@ -266,7 +269,7 @@ class AndroidBluetoothPlugin extends BluetoothPlugin<BluetoothServerSocket> {
 			appContext.unregisterReceiver(receiver);
 		}
 		// Shuffle the addresses so we don't always try the same one first
-		Collections.shuffle(addresses);
+		shuffle(addresses);
 		return addresses;
 	}
 

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

@@ -3,6 +3,7 @@ package org.briarproject.bramble.plugin.bluetooth;
 import android.content.Context;
 
 import org.briarproject.bramble.api.event.EventBus;
+import org.briarproject.bramble.api.io.TimeoutMonitor;
 import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
 import org.briarproject.bramble.api.plugin.Backoff;
 import org.briarproject.bramble.api.plugin.BackoffFactory;
@@ -25,6 +26,7 @@ import static org.briarproject.bramble.api.plugin.BluetoothConstants.ID;
 public class AndroidBluetoothPluginFactory implements DuplexPluginFactory {
 
 	private static final int MAX_LATENCY = 30 * 1000; // 30 seconds
+	private static final int MAX_IDLE_TIME = 30 * 1000; // 30 seconds
 	private static final int MIN_POLLING_INTERVAL = 60 * 1000; // 1 minute
 	private static final int MAX_POLLING_INTERVAL = 10 * 60 * 1000; // 10 mins
 	private static final double BACKOFF_BASE = 1.2;
@@ -35,18 +37,20 @@ public class AndroidBluetoothPluginFactory implements DuplexPluginFactory {
 	private final SecureRandom secureRandom;
 	private final EventBus eventBus;
 	private final Clock clock;
+	private final TimeoutMonitor timeoutMonitor;
 	private final BackoffFactory backoffFactory;
 
 	public AndroidBluetoothPluginFactory(Executor ioExecutor,
 			AndroidExecutor androidExecutor, Context appContext,
 			SecureRandom secureRandom, EventBus eventBus, Clock clock,
-			BackoffFactory backoffFactory) {
+			TimeoutMonitor timeoutMonitor, BackoffFactory backoffFactory) {
 		this.ioExecutor = ioExecutor;
 		this.androidExecutor = androidExecutor;
 		this.appContext = appContext;
 		this.secureRandom = secureRandom;
 		this.eventBus = eventBus;
 		this.clock = clock;
+		this.timeoutMonitor = timeoutMonitor;
 		this.backoffFactory = backoffFactory;
 	}
 
@@ -63,12 +67,13 @@ public class AndroidBluetoothPluginFactory implements DuplexPluginFactory {
 	@Override
 	public DuplexPlugin createPlugin(PluginCallback callback) {
 		BluetoothConnectionLimiter connectionLimiter =
-				new BluetoothConnectionLimiterImpl();
+				new BluetoothConnectionLimiterImpl(eventBus, clock);
 		Backoff backoff = backoffFactory.createBackoff(MIN_POLLING_INTERVAL,
 				MAX_POLLING_INTERVAL, BACKOFF_BASE);
 		AndroidBluetoothPlugin plugin = new AndroidBluetoothPlugin(
-				connectionLimiter, ioExecutor, androidExecutor, appContext,
-				secureRandom, clock, backoff, callback, MAX_LATENCY);
+				connectionLimiter, timeoutMonitor, ioExecutor, secureRandom,
+				androidExecutor, appContext, clock, backoff,
+				callback, MAX_LATENCY, MAX_IDLE_TIME);
 		eventBus.addListener(plugin);
 		return plugin;
 	}

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

@@ -2,6 +2,7 @@ package org.briarproject.bramble.plugin.bluetooth;
 
 import android.bluetooth.BluetoothSocket;
 
+import org.briarproject.bramble.api.io.TimeoutMonitor;
 import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
 import org.briarproject.bramble.api.plugin.Plugin;
 import org.briarproject.bramble.api.plugin.duplex.AbstractDuplexTransportConnection;
@@ -10,24 +11,33 @@ import java.io.IOException;
 import java.io.InputStream;
 import java.io.OutputStream;
 
+import static org.briarproject.bramble.api.plugin.BluetoothConstants.PROP_ADDRESS;
+import static org.briarproject.bramble.util.AndroidUtils.isValidBluetoothAddress;
+
 @NotNullByDefault
 class AndroidBluetoothTransportConnection
 		extends AbstractDuplexTransportConnection {
 
-	private final BluetoothConnectionLimiter connectionManager;
+	private final BluetoothConnectionLimiter connectionLimiter;
 	private final BluetoothSocket socket;
+	private final InputStream in;
 
 	AndroidBluetoothTransportConnection(Plugin plugin,
-			BluetoothConnectionLimiter connectionManager,
-			BluetoothSocket socket) {
+			BluetoothConnectionLimiter connectionLimiter,
+			TimeoutMonitor timeoutMonitor, BluetoothSocket socket)
+			throws IOException {
 		super(plugin);
-		this.connectionManager = connectionManager;
+		this.connectionLimiter = connectionLimiter;
 		this.socket = socket;
+		in = timeoutMonitor.createTimeoutInputStream(
+				socket.getInputStream(), plugin.getMaxIdleTime() * 2);
+		String address = socket.getRemoteDevice().getAddress();
+		if (isValidBluetoothAddress(address)) remote.put(PROP_ADDRESS, address);
 	}
 
 	@Override
-	protected InputStream getInputStream() throws IOException {
-		return socket.getInputStream();
+	protected InputStream getInputStream() {
+		return in;
 	}
 
 	@Override
@@ -40,7 +50,7 @@ class AndroidBluetoothTransportConnection
 		try {
 			socket.close();
 		} finally {
-			connectionManager.connectionClosed(this);
+			connectionLimiter.connectionClosed(this, exception);
 		}
 	}
 }

bramble-android/src/main/java/org/briarproject/bramble/plugin/tcp/AndroidLanTcpPlugin.java

@@ -9,17 +9,17 @@ import android.net.wifi.WifiManager;
 
 import org.briarproject.bramble.PoliteExecutor;
 import org.briarproject.bramble.api.event.Event;
+import org.briarproject.bramble.api.event.EventListener;
 import org.briarproject.bramble.api.network.event.NetworkStatusEvent;
 import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
 import org.briarproject.bramble.api.plugin.Backoff;
 import org.briarproject.bramble.api.plugin.PluginCallback;
-import org.briarproject.bramble.api.settings.Settings;
 
 import java.io.IOException;
 import java.net.InetAddress;
 import java.net.Socket;
 import java.net.UnknownHostException;
-import java.util.Collection;
+import java.util.List;
 import java.util.concurrent.Executor;
 import java.util.logging.Logger;
 
@@ -32,31 +32,14 @@ import static android.net.ConnectivityManager.TYPE_WIFI;
 import static android.os.Build.VERSION.SDK_INT;
 import static java.util.Collections.emptyList;
 import static java.util.Collections.singletonList;
-import static java.util.logging.Level.WARNING;
 import static java.util.logging.Logger.getLogger;
-import static org.briarproject.bramble.api.plugin.Plugin.State.ACTIVE;
-import static org.briarproject.bramble.api.plugin.Plugin.State.INACTIVE;
-import static org.briarproject.bramble.util.IoUtils.tryToClose;
 
 @NotNullByDefault
-class AndroidLanTcpPlugin extends LanTcpPlugin {
+class AndroidLanTcpPlugin extends LanTcpPlugin implements EventListener {
 
 	private static final Logger LOG =
 			getLogger(AndroidLanTcpPlugin.class.getName());
 
-	private static final byte[] WIFI_AP_ADDRESS_BYTES =
-			{(byte) 192, (byte) 168, 43, 1};
-	private static final InetAddress WIFI_AP_ADDRESS;
-
-	static {
-		try {
-			WIFI_AP_ADDRESS = InetAddress.getByAddress(WIFI_AP_ADDRESS_BYTES);
-		} catch (UnknownHostException e) {
-			// Should only be thrown if the address has an illegal length
-			throw new AssertionError(e);
-		}
-	}
-
 	private final Executor connectionStatusExecutor;
 	private final ConnectivityManager connectivityManager;
 	@Nullable
@@ -66,8 +49,9 @@ class AndroidLanTcpPlugin extends LanTcpPlugin {
 
 	AndroidLanTcpPlugin(Executor ioExecutor, Context appContext,
 			Backoff backoff, PluginCallback callback, int maxLatency,
-			int maxIdleTime) {
-		super(ioExecutor, backoff, callback, maxLatency, maxIdleTime);
+			int maxIdleTime, int connectionTimeout) {
+		super(ioExecutor, backoff, callback, maxLatency, maxIdleTime,
+				connectionTimeout);
 		// Don't execute more than one connection status check at a time
 		connectionStatusExecutor =
 				new PoliteExecutor("AndroidLanTcpPlugin", ioExecutor, 1);
@@ -83,27 +67,36 @@ class AndroidLanTcpPlugin extends LanTcpPlugin {
 	@Override
 	public void start() {
 		if (used.getAndSet(true)) throw new IllegalStateException();
-		Settings settings = callback.getSettings();
-		state.setStarted(settings.getBoolean(PREF_PLUGIN_ENABLE, false));
+		initialisePortProperty();
+		running = true;
 		updateConnectionStatus();
 	}
 
+	@Override
+	public void stop() {
+		running = false;
+		tryToClose(socket);
+	}
+
 	@Override
 	protected Socket createSocket() throws IOException {
 		return socketFactory.createSocket();
 	}
 
 	@Override
-	protected Collection<InetAddress> getLocalIpAddresses() {
+	protected List<InetAddress> getUsableLocalInetAddresses() {
 		// If the device doesn't have wifi, don't open any sockets
 		if (wifiManager == null) return emptyList();
-		// If we're connected to a wifi network, use that network
+		// If we're connected to a wifi network, return its address
 		WifiInfo info = wifiManager.getConnectionInfo();
-		if (info != null && info.getIpAddress() != 0)
+		if (info != null && info.getIpAddress() != 0) {
 			return singletonList(intToInetAddress(info.getIpAddress()));
+		}
 		// If we're running an access point, return its address
-		if (super.getLocalIpAddresses().contains(WIFI_AP_ADDRESS))
-			return singletonList(WIFI_AP_ADDRESS);
+		for (InetAddress addr : getLocalInetAddresses()) {
+			if (addr.equals(WIFI_AP_ADDRESS)) return singletonList(addr);
+			if (addr.equals(WIFI_DIRECT_AP_ADDRESS)) return singletonList(addr);
+		}
 		// No suitable addresses
 		return emptyList();
 	}
@@ -137,37 +130,30 @@ class AndroidLanTcpPlugin extends LanTcpPlugin {
 
 	@Override
 	public void eventOccurred(Event e) {
-		super.eventOccurred(e);
 		if (e instanceof NetworkStatusEvent) updateConnectionStatus();
 	}
 
 	private void updateConnectionStatus() {
 		connectionStatusExecutor.execute(() -> {
-			State s = getState();
-			if (s != ACTIVE && s != INACTIVE) return;
-			Collection<InetAddress> addrs = getLocalIpAddresses();
-			if (addrs.contains(WIFI_AP_ADDRESS)) {
+			if (!running) return;
+			List<InetAddress> addrs = getUsableLocalInetAddresses();
+			if (addrs.contains(WIFI_AP_ADDRESS)
+					|| addrs.contains(WIFI_DIRECT_AP_ADDRESS)) {
 				LOG.info("Providing wifi hotspot");
 				// There's no corresponding Network object and thus no way
 				// to get a suitable socket factory, so we won't be able to
 				// make outgoing connections on API 21+ if another network
 				// has internet access
 				socketFactory = SocketFactory.getDefault();
-				if (s == INACTIVE) bind();
+				if (socket == null || socket.isClosed()) bind();
 			} else if (addrs.isEmpty()) {
 				LOG.info("Not connected to wifi");
 				socketFactory = SocketFactory.getDefault();
-				// Server socket may not have been closed automatically when
-				// interface was taken down. Socket will be cleared and state
-				// updated in acceptContactConnections()
-				if (s == ACTIVE) {
-					LOG.info("Closing server socket");
-					tryToClose(state.getServerSocket(), LOG, WARNING);
-				}
+				tryToClose(socket);
 			} else {
 				LOG.info("Connected to wifi");
 				socketFactory = getSocketFactory();
-				if (s == INACTIVE) bind();
+				if (socket == null || socket.isClosed()) bind();
 			}
 		});
 	}

bramble-android/src/main/java/org/briarproject/bramble/plugin/tcp/AndroidLanTcpPluginFactory.java

@@ -21,10 +21,11 @@ import static org.briarproject.bramble.api.plugin.LanTcpConstants.ID;
 @NotNullByDefault
 public class AndroidLanTcpPluginFactory implements DuplexPluginFactory {
 
-	private static final int MAX_LATENCY = 30 * 1000; // 30 seconds
-	private static final int MAX_IDLE_TIME = 30 * 1000; // 30 seconds
-	private static final int MIN_POLLING_INTERVAL = 60 * 1000; // 1 minute
-	private static final int MAX_POLLING_INTERVAL = 10 * 60 * 1000; // 10 mins
+	private static final int MAX_LATENCY = 30_000; // 30 seconds
+	private static final int MAX_IDLE_TIME = 30_000; // 30 seconds
+	private static final int CONNECTION_TIMEOUT = 3_000; // 3 seconds
+	private static final int MIN_POLLING_INTERVAL = 60_000; // 1 minute
+	private static final int MAX_POLLING_INTERVAL = 600_000; // 10 mins
 	private static final double BACKOFF_BASE = 1.2;
 
 	private final Executor ioExecutor;
@@ -55,7 +56,8 @@ public class AndroidLanTcpPluginFactory implements DuplexPluginFactory {
 		Backoff backoff = backoffFactory.createBackoff(MIN_POLLING_INTERVAL,
 				MAX_POLLING_INTERVAL, BACKOFF_BASE);
 		AndroidLanTcpPlugin plugin = new AndroidLanTcpPlugin(ioExecutor,
-				appContext, backoff, callback, MAX_LATENCY, MAX_IDLE_TIME);
+				appContext, backoff, callback, MAX_LATENCY, MAX_IDLE_TIME,
+				CONNECTION_TIMEOUT);
 		eventBus.addListener(plugin);
 		return plugin;
 	}

bramble-android/src/main/java/org/briarproject/bramble/plugin/tor/AndroidTorPlugin.java

@@ -74,6 +74,7 @@ class AndroidTorPlugin extends TorPlugin {
 
 	@Override
 	protected void enableNetwork(boolean enable) throws IOException {
+		if (!running) return;
 		if (enable) wakeLock.acquire();
 		super.enableNetwork(enable);
 		if (!enable) wakeLock.release();

bramble-android/src/main/java/org/briarproject/bramble/system/AndroidLocationUtils.java

@@ -61,12 +61,12 @@ class AndroidLocationUtils implements LocationUtils {
 	private String getCountryFromPhoneNetwork() {
 		Object o = appContext.getSystemService(TELEPHONY_SERVICE);
 		TelephonyManager tm = (TelephonyManager) o;
-		return tm == null ? "" : tm.getNetworkCountryIso();
+		return tm.getNetworkCountryIso();
 	}
 
 	private String getCountryFromSimCard() {
 		Object o = appContext.getSystemService(TELEPHONY_SERVICE);
 		TelephonyManager tm = (TelephonyManager) o;
-		return tm == null ? "" : tm.getSimCountryIso();
+		return tm.getSimCountryIso();
 	}
 }

bramble-android/src/main/java/org/briarproject/bramble/util/AndroidUtils.java

@@ -71,7 +71,7 @@ public class AndroidUtils {
 		return new Pair<>("", "");
 	}
 
-	private static boolean isValidBluetoothAddress(@Nullable String address) {
+	public static boolean isValidBluetoothAddress(@Nullable String address) {
 		return !StringUtils.isNullOrEmpty(address)
 				&& BluetoothAdapter.checkBluetoothAddress(address)
 				&& !address.equals(FAKE_BLUETOOTH_ADDRESS);

bramble-android/src/test/java/org/briarproject/bramble/account/AndroidAccountManagerTest.java

@@ -72,7 +72,9 @@ public class AndroidAccountManagerTest extends BrambleMockTestCase {
 	@Test
 	public void testDeleteAccountClearsSharedPrefsAndDeletesFiles()
 			throws Exception {
-		// Directories 'lib' and 'shared_prefs' should be spared
+		// Directories 'code_cache', 'lib' and 'shared_prefs' should be spared
+		File codeCacheDir = new File(testDir, "code_cache");
+		File codeCacheFile = new File(codeCacheDir, "file");
 		File libDir = new File(testDir, "lib");
 		File libFile = new File(libDir, "file");
 		File sharedPrefsDir = new File(testDir, "shared_prefs");
@@ -111,6 +113,8 @@ public class AndroidAccountManagerTest extends BrambleMockTestCase {
 
 		assertTrue(dbDir.mkdirs());
 		assertTrue(keyDir.mkdirs());
+		assertTrue(codeCacheDir.mkdirs());
+		assertTrue(codeCacheFile.createNewFile());
 		assertTrue(libDir.mkdirs());
 		assertTrue(libFile.createNewFile());
 		assertTrue(sharedPrefsDir.mkdirs());
@@ -126,6 +130,8 @@ public class AndroidAccountManagerTest extends BrambleMockTestCase {
 
 		assertFalse(dbDir.exists());
 		assertFalse(keyDir.exists());
+		assertTrue(codeCacheDir.exists());
+		assertTrue(codeCacheFile.exists());
 		assertTrue(libDir.exists());
 		assertTrue(libFile.exists());
 		assertTrue(sharedPrefsDir.exists());

bramble-android/witness.gradle

@@ -70,7 +70,7 @@ dependencyVerification {
         'org.bouncycastle:bcpkix-jdk15on:1.56:bcpkix-jdk15on-1.56.jar:7043dee4e9e7175e93e0b36f45b1ec1ecb893c5f755667e8b916eb8dd201c6ca',
         'org.bouncycastle:bcprov-jdk15on:1.56:bcprov-jdk15on-1.56.jar:963e1ee14f808ffb99897d848ddcdb28fa91ddda867eb18d303e82728f878349',
         'org.briarproject:obfs4proxy-android:0.0.11-2:obfs4proxy-android-0.0.11-2.zip:57e55cbe87aa2aac210fdbb6cd8cdeafe15f825406a08ebf77a8b787aa2c6a8a',
-        'org.briarproject:tor-android:0.3.5.9:tor-android-0.3.5.9.zip:853b0440feccd6904bd03e6b2de53a62ebcde1d58068beeadc447a7dff950bc8',
+        'org.briarproject:tor-android:0.3.5.10:tor-android-0.3.5.10.zip:edd83bf557fcff2105eaa0bdb3f607a6852ebe7360920929ae3039dd5f4774c5',
         'org.checkerframework:checker-compat-qual:2.5.3:checker-compat-qual-2.5.3.jar:d76b9afea61c7c082908023f0cbc1427fab9abd2df915c8b8a3e7a509bccbc6d',
         'org.checkerframework:checker-qual:2.5.2:checker-qual-2.5.2.jar:64b02691c8b9d4e7700f8ee2e742dce7ea2c6e81e662b7522c9ee3bf568c040a',
         'org.codehaus.groovy:groovy-all:2.4.15:groovy-all-2.4.15.jar:51d6c4e71782e85674239189499854359d380fb75e1a703756e3aaa5b98a5af0',

bramble-api/src/main/java/org/briarproject/bramble/api/account/AccountManager.java

@@ -1,5 +1,6 @@
 package org.briarproject.bramble.api.account;
 
+import org.briarproject.bramble.api.crypto.DecryptionException;
 import org.briarproject.bramble.api.crypto.SecretKey;
 import org.briarproject.bramble.api.identity.IdentityManager;
 import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
@@ -13,7 +14,8 @@ public interface AccountManager {
 	 * Returns true if the manager has the database key. This will be false
 	 * before {@link #createAccount(String, String)} or {@link #signIn(String)}
 	 * has been called, and true after {@link #createAccount(String, String)}
-	 * or {@link #signIn(String)} has returned true, until the process exits.
+	 * or {@link #signIn(String)} has returned true, until
+	 * {@link #deleteAccount()} is called or the process exits.
 	 */
 	boolean hasDatabaseKey();
 
@@ -22,25 +24,22 @@ public interface AccountManager {
 	 * before {@link #createAccount(String, String)} or {@link #signIn(String)}
 	 * has been called, and non-null after
 	 * {@link #createAccount(String, String)} or {@link #signIn(String)} has
-	 * returned true, until the process exits.
+	 * returned true, until {@link #deleteAccount()} is called or the process
+	 * exits.
 	 */
 	@Nullable
 	SecretKey getDatabaseKey();
 
 	/**
-	 * Returns true if the encrypted database key can be loaded from disk, and
-	 * the database directory exists and is a directory.
+	 * Returns true if the encrypted database key can be loaded from disk.
 	 */
 	boolean accountExists();
 
 	/**
 	 * Creates an identity with the given name and registers it with the
 	 * {@link IdentityManager}. Creates a database key, encrypts it with the
-	 * given password and stores it on disk.
-	 * <p/>
-	 * This method does not create the database directory, so
-	 * {@link #accountExists()} will continue to return false until the
-	 * database directory is created.
+	 * given password and stores it on disk. {@link #accountExists()} will
+	 * return true after this method returns true.
 	 */
 	boolean createAccount(String name, String password);
 
@@ -54,17 +53,19 @@ public interface AccountManager {
 	 * Loads the encrypted database key from disk and decrypts it with the
 	 * given password.
 	 *
-	 * @return true if the database key was successfully loaded and decrypted.
+	 * @throws DecryptionException If the database key could not be loaded and
+	 * decrypted.
 	 */
-	boolean signIn(String password);
+	void signIn(String password) throws DecryptionException;
 
 	/**
 	 * Loads the encrypted database key from disk, decrypts it with the old
 	 * password, encrypts it with the new password, and stores it on disk,
 	 * replacing the old key.
 	 *
-	 * @return true if the database key was successfully loaded, re-encrypted
-	 * and stored.
+	 * @throws DecryptionException If the database key could not be loaded and
+	 * decrypted.
 	 */
-	boolean changePassword(String oldPassword, String newPassword);
+	void changePassword(String oldPassword, String newPassword)
+			throws DecryptionException;
 }

bramble-api/src/main/java/org/briarproject/bramble/api/crypto/CryptoComponent.java

@@ -142,16 +142,17 @@ public interface CryptoComponent {
 	/**
 	 * Decrypts and authenticates the given ciphertext that has been read from
 	 * storage. The encryption and authentication keys are derived from the
-	 * given password. Returns null if the ciphertext cannot be decrypted and
-	 * authenticated (for example, if the password is wrong).
+	 * given password.
 	 *
 	 * @param keyStrengthener Used to strengthen the password-based key. If
 	 * null, or if strengthening was not used when encrypting the ciphertext,
 	 * the password-based key will not be strengthened
+	 * @throws DecryptionException If the ciphertext cannot be decrypted and
+	 * authenticated (for example, if the password is wrong).
 	 */
-	@Nullable
 	byte[] decryptWithPassword(byte[] ciphertext, String password,
-			@Nullable KeyStrengthener keyStrengthener);
+			@Nullable KeyStrengthener keyStrengthener)
+			throws DecryptionException;
 
 	/**
 	 * Returns true if the given ciphertext was encrypted using a strengthened

bramble-api/src/main/java/org/briarproject/bramble/api/crypto/DecryptionException.java

@@ -0,0 +1,17 @@
+package org.briarproject.bramble.api.crypto;
+
+import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
+
+@NotNullByDefault
+public class DecryptionException extends Exception {
+
+	private final DecryptionResult result;
+
+	public DecryptionException(DecryptionResult result) {
+		this.result = result;
+	}
+
+	public DecryptionResult getDecryptionResult() {
+		return result;
+	}
+}

bramble-api/src/main/java/org/briarproject/bramble/api/crypto/DecryptionResult.java

@@ -0,0 +1,29 @@
+package org.briarproject.bramble.api.crypto;
+
+/**
+ * The result of a password-based decryption operation.
+ */
+public enum DecryptionResult {
+
+	/**
+	 * Decryption succeeded.
+	 */
+	SUCCESS,
+
+	/**
+	 * Decryption failed because the format of the ciphertext was invalid.
+	 */
+	INVALID_CIPHERTEXT,
+
+	/**
+	 * Decryption failed because the {@link KeyStrengthener} used for
+	 * encryption was not available for decryption.
+	 */
+	KEY_STRENGTHENER_ERROR,
+
+	/**
+	 * Decryption failed because the password used for decryption did not match
+	 * the password used for encryption.
+	 */
+	INVALID_PASSWORD
+}

bramble-api/src/main/java/org/briarproject/bramble/api/event/EventBus.java

@@ -18,8 +18,6 @@ public interface EventBus {
 	/**
 	 * Asynchronously notifies all listeners of an event. Listeners are
 	 * notified on the {@link EventExecutor}.
-	 * <p>
-	 * This method can safely be called while holding a lock.
 	 */
 	void broadcast(Event e);
 }

bramble-api/src/main/java/org/briarproject/bramble/api/io/TimeoutMonitor.java

@@ -0,0 +1,15 @@
+package org.briarproject.bramble.api.io;
+
+import java.io.InputStream;
+
+public interface TimeoutMonitor {
+
+	/**
+	 * Returns an {@link InputStream} that wraps the given stream and allows
+	 * read timeouts to be detected.
+	 *
+	 * @param timeoutMs The read timeout in milliseconds. Timeouts will be
+	 * detected eventually but are not guaranteed to be detected immediately.
+	 */
+	InputStream createTimeoutInputStream(InputStream in, long timeoutMs);
+}

bramble-api/src/main/java/org/briarproject/bramble/api/plugin/BluetoothConstants.java

@@ -9,6 +9,5 @@ public interface BluetoothConstants {
 	String PROP_ADDRESS = "address";
 	String PROP_UUID = "uuid";
 
-	// Reason code returned by Plugin#getReasonDisabled()
-	int REASON_NO_BT_ADAPTER = 2;
+	String PREF_BT_ENABLE = "enable";
 }

bramble-api/src/main/java/org/briarproject/bramble/api/plugin/LanTcpConstants.java

@@ -4,10 +4,10 @@ public interface LanTcpConstants {
 
 	TransportId ID = new TransportId("org.briarproject.bramble.lan");
 
-	// a transport property (shared with contacts)
+	// Transport properties (shared with contacts)
 	String PROP_IP_PORTS = "ipPorts";
+	String PROP_PORT = "port";
 
-	// a local setting
+	// A local setting
 	String PREF_LAN_IP_PORTS = "ipPorts";
-
 }

bramble-api/src/main/java/org/briarproject/bramble/api/plugin/Plugin.java

@@ -3,57 +3,12 @@ package org.briarproject.bramble.api.plugin;
 import org.briarproject.bramble.api.Pair;
 import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
 import org.briarproject.bramble.api.properties.TransportProperties;
-import org.briarproject.bramble.api.settings.SettingsManager;
 
 import java.util.Collection;
 
 @NotNullByDefault
 public interface Plugin {
 
-	enum State {
-
-		/**
-		 * The plugin has not been started, has been stopped, or is disabled by
-		 * settings.
-		 */
-		DISABLED,
-
-		/**
-		 * The plugin is being enabled and can't yet make or receive
-		 * connections.
-		 */
-		ENABLING,
-
-		/**
-		 * The plugin is enabled and can make or receive connections.
-		 */
-		ACTIVE,
-
-		/**
-		 * The plugin is enabled but can't make or receive connections
-		 */
-		INACTIVE
-	}
-
-	/**
-	 * The string for the boolean preference
-	 * to use with the {@link SettingsManager} to enable or disable the plugin.
-	 */
-	String PREF_PLUGIN_ENABLE = "enable";
-
-	/**
-	 * Reason code returned by {@link #getReasonDisabled()} to indicate that
-	 * the plugin is disabled because it has not been started or has been
-	 * stopped.
-	 */
-	int REASON_STARTING_STOPPING = 0;
-
-	/**
-	 * Reason code returned by {@link #getReasonDisabled()} to indicate that
-	 * the plugin has been disabled by the user.
-	 */
-	int REASON_USER = 1;
-
 	/**
 	 * Returns the plugin's transport identifier.
 	 */
@@ -80,19 +35,9 @@ public interface Plugin {
 	void stop() throws PluginException;
 
 	/**
-	 * Returns the current state of the plugin.
+	 * Returns true if the plugin is running.
 	 */
-	State getState();
-
-	/**
-	 * Returns an integer code indicating why the plugin is
-	 * {@link State#DISABLED disabled}, or -1 if the plugin is not disabled.
-	 * <p>
-	 * The codes used are plugin-specific, except the generic codes
-	 * {@link #REASON_STARTING_STOPPING} and {@link #REASON_USER}, which may
-	 * be used by any plugin.
-	 */
-	int getReasonDisabled();
+	boolean isRunning();
 
 	/**
 	 * Returns true if the plugin should be polled periodically to attempt to

bramble-api/src/main/java/org/briarproject/bramble/api/plugin/PluginCallback.java

@@ -1,10 +1,6 @@
 package org.briarproject.bramble.api.plugin;
 
 import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
-import org.briarproject.bramble.api.plugin.Plugin.State;
-import org.briarproject.bramble.api.plugin.event.TransportActiveEvent;
-import org.briarproject.bramble.api.plugin.event.TransportInactiveEvent;
-import org.briarproject.bramble.api.plugin.event.TransportStateEvent;
 import org.briarproject.bramble.api.properties.TransportProperties;
 import org.briarproject.bramble.api.settings.Settings;
 
@@ -36,17 +32,12 @@ public interface PluginCallback extends ConnectionHandler {
 	void mergeLocalProperties(TransportProperties p);
 
 	/**
-	 * Informs the callback of the plugin's current state.
-	 * <p>
-	 * If the current state is different from the previous state, the callback
-	 * will broadcast a {@link TransportStateEvent}. If the current state is
-	 * {@link State#ACTIVE} and the previous state was not
-	 * {@link State#ACTIVE}, the callback will broadcast a
-	 * {@link TransportActiveEvent}. If the current state is not
-	 * {@link State#ACTIVE} and the previous state was {@link State#ACTIVE},
-	 * the callback will broadcast a {@link TransportInactiveEvent}.
-	 * <p>
-	 * This method can safely be called while holding a lock.
+	 * Signals that the transport is enabled.
 	 */
-	void pluginStateChanged(State state);
+	void transportEnabled();
+
+	/**
+	 * Signals that the transport is disabled.
+	 */
+	void transportDisabled();
 }

bramble-api/src/main/java/org/briarproject/bramble/api/plugin/PluginManager.java

@@ -41,17 +41,4 @@ public interface PluginManager {
 	 * Returns any duplex plugins that support rendezvous.
 	 */
 	Collection<DuplexPlugin> getRendezvousPlugins();
-
-	/**
-	 * Enables or disables the plugin
-	 * identified by the given {@link TransportId}.
-	 * <p>
-	 * Note that this applies the change asynchronously
-	 * and there are no order guarantees.
-	 * <p>
-	 * If no plugin with the given {@link TransportId} is registered,
-	 * this is a no-op.
-	 */
-	void setPluginEnabled(TransportId t, boolean enabled);
-
 }

bramble-api/src/main/java/org/briarproject/bramble/api/plugin/TorConstants.java

@@ -23,8 +23,4 @@ public interface TorConstants {
 	int PREF_TOR_NETWORK_WITH_BRIDGES = 2;
 	int PREF_TOR_NETWORK_NEVER = 3;
 
-	// Reason codes returned by Plugin#getReasonDisabled()
-	int REASON_BATTERY = 2;
-	int REASON_MOBILE_DATA = 3;
-	int REASON_COUNTRY_BLOCKED = 4;
 }

bramble-api/src/main/java/org/briarproject/bramble/api/plugin/duplex/AbstractDuplexTransportConnection.java

@@ -4,6 +4,7 @@ import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
 import org.briarproject.bramble.api.plugin.Plugin;
 import org.briarproject.bramble.api.plugin.TransportConnectionReader;
 import org.briarproject.bramble.api.plugin.TransportConnectionWriter;
+import org.briarproject.bramble.api.properties.TransportProperties;
 
 import java.io.IOException;
 import java.io.InputStream;
@@ -14,6 +15,8 @@ import java.util.concurrent.atomic.AtomicBoolean;
 public abstract class AbstractDuplexTransportConnection
 		implements DuplexTransportConnection {
 
+	protected final TransportProperties remote = new TransportProperties();
+
 	private final Plugin plugin;
 	private final Reader reader;
 	private final Writer writer;
@@ -44,6 +47,11 @@ public abstract class AbstractDuplexTransportConnection
 		return writer;
 	}
 
+	@Override
+	public TransportProperties getRemoteProperties() {
+		return remote;
+	}
+
 	private class Reader implements TransportConnectionReader {
 
 		@Override

bramble-api/src/main/java/org/briarproject/bramble/api/plugin/duplex/DuplexTransportConnection.java

@@ -3,6 +3,7 @@ package org.briarproject.bramble.api.plugin.duplex;
 import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
 import org.briarproject.bramble.api.plugin.TransportConnectionReader;
 import org.briarproject.bramble.api.plugin.TransportConnectionWriter;
+import org.briarproject.bramble.api.properties.TransportProperties;
 
 /**
  * An interface for reading and writing data over a duplex transport. The
@@ -23,4 +24,10 @@ public interface DuplexTransportConnection {
 	 * for writing to the connection.
 	 */
 	TransportConnectionWriter getWriter();
+
+	/**
+	 * Returns a possibly empty set of {@link TransportProperties} describing
+	 * the remote peer.
+	 */
+	TransportProperties getRemoteProperties();
 }

bramble-api/src/main/java/org/briarproject/bramble/api/plugin/event/TransportDisabledEvent.java

@@ -2,22 +2,20 @@ package org.briarproject.bramble.api.plugin.event;
 
 import org.briarproject.bramble.api.event.Event;
 import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
-import org.briarproject.bramble.api.plugin.Plugin.State;
 import org.briarproject.bramble.api.plugin.TransportId;
 
 import javax.annotation.concurrent.Immutable;
 
 /**
- * An event that is broadcast when a plugin enters the {@link State#ACTIVE}
- * state.
+ * An event that is broadcast when a transport is disabled.
  */
 @Immutable
 @NotNullByDefault
-public class TransportActiveEvent extends Event {
+public class TransportDisabledEvent extends Event {
 
 	private final TransportId transportId;
 
-	public TransportActiveEvent(TransportId transportId) {
+	public TransportDisabledEvent(TransportId transportId) {
 		this.transportId = transportId;
 	}
 

bramble-api/src/main/java/org/briarproject/bramble/api/plugin/event/TransportEnabledEvent.java

@@ -2,22 +2,20 @@ package org.briarproject.bramble.api.plugin.event;
 
 import org.briarproject.bramble.api.event.Event;
 import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
-import org.briarproject.bramble.api.plugin.Plugin.State;
 import org.briarproject.bramble.api.plugin.TransportId;
 
 import javax.annotation.concurrent.Immutable;
 
 /**
- * An event that is broadcast when a plugin leaves the {@link State#ACTIVE}
- * state.
+ * An event that is broadcast when a transport is enabled.
  */
 @Immutable
 @NotNullByDefault
-public class TransportInactiveEvent extends Event {
+public class TransportEnabledEvent extends Event {
 
 	private final TransportId transportId;
 
-	public TransportInactiveEvent(TransportId transportId) {
+	public TransportEnabledEvent(TransportId transportId) {
 		this.transportId = transportId;
 	}
 

bramble-api/src/main/java/org/briarproject/bramble/api/properties/TransportPropertyConstants.java

@@ -11,4 +11,28 @@ public interface TransportPropertyConstants {
 	 * The maximum length of a property's key or value in UTF-8 bytes.
 	 */
 	int MAX_PROPERTY_LENGTH = 100;
+
+	/**
+	 * Message metadata key for the transport ID of a local or remote update,
+	 * as a BDF string.
+	 */
+	String MSG_KEY_TRANSPORT_ID = "transportId";
+
+	/**
+	 * Message metadata key for the version number of a local or remote update,
+	 * as a BDF long.
+	 */
+	String MSG_KEY_VERSION = "version";
+
+	/**
+	 * Message metadata key for whether an update is local or remote, as a BDF
+	 * boolean.
+	 */
+	String MSG_KEY_LOCAL = "local";
+
+	/**
+	 * Group metadata key for any discovered transport properties of the
+	 * contact, as a BDF dictionary.
+	 */
+	String GROUP_KEY_DISCOVERED = "discovered";
 }

bramble-api/src/main/java/org/briarproject/bramble/api/properties/TransportPropertyManager.java

@@ -34,6 +34,14 @@ public interface TransportPropertyManager {
 	void addRemoteProperties(Transaction txn, ContactId c,
 			Map<TransportId, TransportProperties> props) throws DbException;
 
+	/**
+	 * Stores the given properties discovered from an incoming transport
+	 * connection. They will be overridden by any properties received while
+	 * adding the contact or synced from the contact.
+	 */
+	void addRemotePropertiesFromConnection(ContactId c, TransportId t,
+			TransportProperties props) throws DbException;
+
 	/**
 	 * Returns the local transport properties for all transports.
 	 */

bramble-api/src/main/java/org/briarproject/bramble/api/sync/SyncSessionFactory.java

@@ -2,6 +2,7 @@ package org.briarproject.bramble.api.sync;
 
 import org.briarproject.bramble.api.contact.ContactId;
 import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
+import org.briarproject.bramble.api.plugin.TransportId;
 import org.briarproject.bramble.api.transport.StreamWriter;
 
 import java.io.InputStream;
@@ -11,9 +12,9 @@ public interface SyncSessionFactory {
 
 	SyncSession createIncomingSession(ContactId c, InputStream in);
 
-	SyncSession createSimplexOutgoingSession(ContactId c, int maxLatency,
-			StreamWriter streamWriter);
+	SyncSession createSimplexOutgoingSession(ContactId c, TransportId t,
+			int maxLatency, StreamWriter streamWriter);
 
-	SyncSession createDuplexOutgoingSession(ContactId c, int maxLatency,
-			int maxIdleTime, StreamWriter streamWriter);
+	SyncSession createDuplexOutgoingSession(ContactId c, TransportId t,
+			int maxLatency, int maxIdleTime, StreamWriter streamWriter);
 }

bramble-api/src/main/java/org/briarproject/bramble/api/sync/event/CloseSyncConnectionsEvent.java

@@ -1,32 +1,26 @@
-package org.briarproject.bramble.api.plugin.event;
+package org.briarproject.bramble.api.sync.event;
 
 import org.briarproject.bramble.api.event.Event;
 import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
-import org.briarproject.bramble.api.plugin.Plugin.State;
 import org.briarproject.bramble.api.plugin.TransportId;
 
 import javax.annotation.concurrent.Immutable;
 
 /**
- * An event that is broadcast when the {@link State state} of a plugin changes.
+ * An event that is broadcast when all sync connections using a given
+ * transport should be closed.
  */
 @Immutable
 @NotNullByDefault
-public class TransportStateEvent extends Event {
+public class CloseSyncConnectionsEvent extends Event {
 
 	private final TransportId transportId;
-	private final State state;
 
-	public TransportStateEvent(TransportId transportId, State state) {
+	public CloseSyncConnectionsEvent(TransportId transportId) {
 		this.transportId = transportId;
-		this.state = state;
 	}
 
 	public TransportId getTransportId() {
 		return transportId;
 	}
-
-	public State getState() {
-		return state;
-	}
 }

bramble-api/src/main/java/org/briarproject/bramble/util/IoUtils.java

@@ -117,4 +117,10 @@ public class IoUtils {
 			throw new IOException(e);
 		}
 	}
+
+	public static boolean isNonEmptyDirectory(File f) {
+		if (!f.isDirectory()) return false;
+		File[] children = f.listFiles();
+		return children != null && children.length > 0;
+	}
 }

bramble-core/src/main/java/org/briarproject/bramble/BrambleCoreModule.java

@@ -9,6 +9,7 @@ import org.briarproject.bramble.db.DatabaseExecutorModule;
 import org.briarproject.bramble.db.DatabaseModule;
 import org.briarproject.bramble.event.EventModule;
 import org.briarproject.bramble.identity.IdentityModule;
+import org.briarproject.bramble.io.IoModule;
 import org.briarproject.bramble.keyagreement.KeyAgreementModule;
 import org.briarproject.bramble.lifecycle.LifecycleModule;
 import org.briarproject.bramble.plugin.PluginModule;
@@ -35,6 +36,7 @@ import dagger.Module;
 		DatabaseExecutorModule.class,
 		EventModule.class,
 		IdentityModule.class,
+		IoModule.class,
 		KeyAgreementModule.class,
 		LifecycleModule.class,
 		PluginModule.class,

bramble-core/src/main/java/org/briarproject/bramble/account/AccountManagerImpl.java

@@ -2,6 +2,7 @@ package org.briarproject.bramble.account;
 
 import org.briarproject.bramble.api.account.AccountManager;
 import org.briarproject.bramble.api.crypto.CryptoComponent;
+import org.briarproject.bramble.api.crypto.DecryptionException;
 import org.briarproject.bramble.api.crypto.KeyStrengthener;
 import org.briarproject.bramble.api.crypto.SecretKey;
 import org.briarproject.bramble.api.db.DatabaseConfig;
@@ -17,6 +18,7 @@ import java.io.FileInputStream;
 import java.io.FileOutputStream;
 import java.io.IOException;
 import java.io.InputStreamReader;
+import java.nio.charset.Charset;
 import java.util.logging.Logger;
 
 import javax.annotation.Nullable;
@@ -24,6 +26,7 @@ import javax.annotation.concurrent.GuardedBy;
 import javax.inject.Inject;
 
 import static java.util.logging.Level.WARNING;
+import static org.briarproject.bramble.api.crypto.DecryptionResult.INVALID_CIPHERTEXT;
 import static org.briarproject.bramble.util.LogUtils.logException;
 import static org.briarproject.bramble.util.StringUtils.fromHexString;
 import static org.briarproject.bramble.util.StringUtils.toHexString;
@@ -95,7 +98,7 @@ class AccountManagerImpl implements AccountManager {
 		}
 		try {
 			BufferedReader reader = new BufferedReader(new InputStreamReader(
-					new FileInputStream(f), "UTF-8"));
+					new FileInputStream(f), Charset.forName("UTF-8")));
 			String key = reader.readLine();
 			reader.close();
 			return key;
@@ -147,7 +150,7 @@ class AccountManagerImpl implements AccountManager {
 	@GuardedBy("stateChangeLock")
 	private void writeDbKeyToFile(String key, File f) throws IOException {
 		FileOutputStream out = new FileOutputStream(f);
-		out.write(key.getBytes("UTF-8"));
+		out.write(key.getBytes(Charset.forName("UTF-8")));
 		out.flush();
 		out.close();
 	}
@@ -155,8 +158,7 @@ class AccountManagerImpl implements AccountManager {
 	@Override
 	public boolean accountExists() {
 		synchronized (stateChangeLock) {
-			return loadEncryptedDatabaseKey() != null
-					&& databaseConfig.getDatabaseDirectory().isDirectory();
+			return loadEncryptedDatabaseKey() != null;
 		}
 	}
 
@@ -193,31 +195,24 @@ class AccountManagerImpl implements AccountManager {
 	}
 
 	@Override
-	public boolean signIn(String password) {
+	public void signIn(String password) throws DecryptionException {
 		synchronized (stateChangeLock) {
-			SecretKey key = loadAndDecryptDatabaseKey(password);
-			if (key == null) return false;
-			databaseKey = key;
-			return true;
+			databaseKey = loadAndDecryptDatabaseKey(password);
 		}
 	}
 
 	@GuardedBy("stateChangeLock")
-	@Nullable
-	private SecretKey loadAndDecryptDatabaseKey(String password) {
+	private SecretKey loadAndDecryptDatabaseKey(String password)
+			throws DecryptionException {
 		String hex = loadEncryptedDatabaseKey();
 		if (hex == null) {
 			LOG.warning("Failed to load encrypted database key");
-			return null;
+			throw new DecryptionException(INVALID_CIPHERTEXT);
 		}
 		byte[] ciphertext = fromHexString(hex);
 		KeyStrengthener keyStrengthener = databaseConfig.getKeyStrengthener();
 		byte[] plaintext = crypto.decryptWithPassword(ciphertext, password,
 				keyStrengthener);
-		if (plaintext == null) {
-			LOG.info("Failed to decrypt database key");
-			return null;
-		}
 		SecretKey key = new SecretKey(plaintext);
 		// If the DB key was encrypted with a weak key and a key strengthener
 		// is now available, re-encrypt the DB key with a strengthened key
@@ -230,10 +225,11 @@ class AccountManagerImpl implements AccountManager {
 	}
 
 	@Override
-	public boolean changePassword(String oldPassword, String newPassword) {
+	public void changePassword(String oldPassword, String newPassword)
+			throws DecryptionException {
 		synchronized (stateChangeLock) {
 			SecretKey key = loadAndDecryptDatabaseKey(oldPassword);
-			return key != null && encryptAndStoreDatabaseKey(key, newPassword);
+			encryptAndStoreDatabaseKey(key, newPassword);
 		}
 	}
 }

bramble-core/src/main/java/org/briarproject/bramble/crypto/CryptoComponentImpl.java

@@ -7,6 +7,7 @@ import net.i2p.crypto.eddsa.KeyPairGenerator;
 import org.briarproject.bramble.api.crypto.AgreementPrivateKey;
 import org.briarproject.bramble.api.crypto.AgreementPublicKey;
 import org.briarproject.bramble.api.crypto.CryptoComponent;
+import org.briarproject.bramble.api.crypto.DecryptionException;
 import org.briarproject.bramble.api.crypto.KeyPair;
 import org.briarproject.bramble.api.crypto.KeyParser;
 import org.briarproject.bramble.api.crypto.KeyStrengthener;
@@ -39,6 +40,9 @@ import static java.lang.System.arraycopy;
 import static java.util.logging.Level.INFO;
 import static org.briarproject.bramble.api.crypto.CryptoConstants.KEY_TYPE_AGREEMENT;
 import static org.briarproject.bramble.api.crypto.CryptoConstants.KEY_TYPE_SIGNATURE;
+import static org.briarproject.bramble.api.crypto.DecryptionResult.INVALID_CIPHERTEXT;
+import static org.briarproject.bramble.api.crypto.DecryptionResult.INVALID_PASSWORD;
+import static org.briarproject.bramble.api.crypto.DecryptionResult.KEY_STRENGTHENER_ERROR;
 import static org.briarproject.bramble.util.ByteUtils.INT_32_BYTES;
 import static org.briarproject.bramble.util.LogUtils.logDuration;
 import static org.briarproject.bramble.util.LogUtils.now;
@@ -359,16 +363,17 @@ class CryptoComponentImpl implements CryptoComponent {
 	}
 
 	@Override
-	@Nullable
 	public byte[] decryptWithPassword(byte[] input, String password,
-			@Nullable KeyStrengthener keyStrengthener) {
+			@Nullable KeyStrengthener keyStrengthener)
+			throws DecryptionException {
 		AuthenticatedCipher cipher = new XSalsa20Poly1305AuthenticatedCipher();
 		int macBytes = cipher.getMacBytes();
 		// The input contains the format version, salt, cost parameter, IV,
 		// ciphertext and MAC
 		if (input.length < 1 + PBKDF_SALT_BYTES + INT_32_BYTES
-				+ STORAGE_IV_BYTES + macBytes)
-			return null; // Invalid input
+				+ STORAGE_IV_BYTES + macBytes) {
+			throw new DecryptionException(INVALID_CIPHERTEXT);
+		}
 		int inputOff = 0;
 		// Format version
 		byte formatVersion = input[inputOff];
@@ -376,7 +381,7 @@ class CryptoComponentImpl implements CryptoComponent {
 		// Check whether we support this format version
 		if (formatVersion != PBKDF_FORMAT_SCRYPT &&
 				formatVersion != PBKDF_FORMAT_SCRYPT_STRENGTHENED) {
-			return null;
+			throw new DecryptionException(INVALID_CIPHERTEXT);
 		}
 		// Salt
 		byte[] salt = new byte[PBKDF_SALT_BYTES];
@@ -385,8 +390,9 @@ class CryptoComponentImpl implements CryptoComponent {
 		// Cost parameter
 		long cost = ByteUtils.readUint32(input, inputOff);
 		inputOff += INT_32_BYTES;
-		if (cost < 2 || cost > Integer.MAX_VALUE)
-			return null; // Invalid cost parameter
+		if (cost < 2 || cost > Integer.MAX_VALUE) {
+			throw new DecryptionException(INVALID_CIPHERTEXT);
+		}
 		// IV
 		byte[] iv = new byte[STORAGE_IV_BYTES];
 		arraycopy(input, inputOff, iv, 0, iv.length);
@@ -394,8 +400,10 @@ class CryptoComponentImpl implements CryptoComponent {
 		// Derive the decryption key from the password
 		SecretKey key = passwordBasedKdf.deriveKey(password, salt, (int) cost);
 		if (formatVersion == PBKDF_FORMAT_SCRYPT_STRENGTHENED) {
-			if (keyStrengthener == null || !keyStrengthener.isInitialised())
-				return null; // Can't derive the same strengthened key
+			if (keyStrengthener == null || !keyStrengthener.isInitialised()) {
+				// Can't derive the same strengthened key
+				throw new DecryptionException(KEY_STRENGTHENER_ERROR);
+			}
 			key = keyStrengthener.strengthenKey(key);
 		}
 		// Initialise the cipher
@@ -411,7 +419,7 @@ class CryptoComponentImpl implements CryptoComponent {
 			cipher.process(input, inputOff, inputLen, output, 0);
 			return output;
 		} catch (GeneralSecurityException e) {
-			return null; // Invalid ciphertext
+			throw new DecryptionException(INVALID_PASSWORD);
 		}
 	}
 

bramble-core/src/main/java/org/briarproject/bramble/db/H2Database.java

@@ -25,6 +25,7 @@ import static java.util.logging.Level.INFO;
 import static java.util.logging.Level.WARNING;
 import static java.util.logging.Logger.getLogger;
 import static org.briarproject.bramble.db.JdbcUtils.tryToClose;
+import static org.briarproject.bramble.util.IoUtils.isNonEmptyDirectory;
 import static org.briarproject.bramble.util.LogUtils.logFileOrDir;
 
 /**
@@ -69,8 +70,9 @@ class H2Database extends JdbcDatabase {
 			LOG.info("Contents of account directory before opening DB:");
 			logFileOrDir(LOG, INFO, dir.getParentFile());
 		}
-		boolean reopen = !dir.mkdirs();
+		boolean reopen = isNonEmptyDirectory(dir);
 		if (LOG.isLoggable(INFO)) LOG.info("Reopening DB: " + reopen);
+		if (!reopen && dir.mkdirs()) LOG.info("Created database directory");
 		super.open("org.h2.Driver", reopen, key, listener);
 		if (LOG.isLoggable(INFO)) {
 			LOG.info("Contents of account directory after opening DB:");

bramble-core/src/main/java/org/briarproject/bramble/db/HyperSqlDatabase.java

@@ -20,9 +20,11 @@ import java.util.logging.Logger;
 import javax.annotation.Nullable;
 import javax.inject.Inject;
 
+import static java.util.logging.Level.INFO;
 import static java.util.logging.Level.WARNING;
 import static java.util.logging.Logger.getLogger;
 import static org.briarproject.bramble.db.JdbcUtils.tryToClose;
+import static org.briarproject.bramble.util.IoUtils.isNonEmptyDirectory;
 
 /**
  * Contains all the HSQLDB-specific code for the database.
@@ -64,7 +66,10 @@ class HyperSqlDatabase extends JdbcDatabase {
 	public boolean open(SecretKey key, @Nullable MigrationListener listener)
 			throws DbException {
 		this.key = key;
-		boolean reopen = !config.getDatabaseDirectory().mkdirs();
+		File dir = config.getDatabaseDirectory();
+		boolean reopen = isNonEmptyDirectory(dir);
+		if (LOG.isLoggable(INFO)) LOG.info("Reopening DB: " + reopen);
+		if (!reopen && dir.mkdirs()) LOG.info("Created database directory");
 		super.open("org.hsqldb.jdbc.JDBCDriver", reopen, key, listener);
 		return reopen;
 	}

bramble-core/src/main/java/org/briarproject/bramble/io/IoModule.java

@@ -0,0 +1,18 @@
+package org.briarproject.bramble.io;
+
+import org.briarproject.bramble.api.io.TimeoutMonitor;
+
+import javax.inject.Singleton;
+
+import dagger.Module;
+import dagger.Provides;
+
+@Module
+public class IoModule {
+
+	@Provides
+	@Singleton
+	TimeoutMonitor provideTimeoutMonitor(TimeoutMonitorImpl timeoutMonitor) {
+		return timeoutMonitor;
+	}
+}

bramble-core/src/main/java/org/briarproject/bramble/io/TimeoutInputStream.java

@@ -0,0 +1,104 @@
+package org.briarproject.bramble.io;
+
+import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
+import org.briarproject.bramble.api.system.Clock;
+
+import java.io.IOException;
+import java.io.InputStream;
+
+import javax.annotation.concurrent.GuardedBy;
+
+@NotNullByDefault
+class TimeoutInputStream extends InputStream {
+
+	private final Clock clock;
+	private final InputStream in;
+	private final long timeoutMs;
+	private final CloseListener listener;
+	private final Object lock = new Object();
+	@GuardedBy("lock")
+	private long readStartedMs = -1;
+
+	TimeoutInputStream(Clock clock, InputStream in, long timeoutMs,
+			CloseListener listener) {
+		this.clock = clock;
+		this.in = in;
+		this.timeoutMs = timeoutMs;
+		this.listener = listener;
+	}
+
+	@Override
+	public int read() throws IOException {
+		synchronized (lock) {
+			readStartedMs = clock.currentTimeMillis();
+		}
+		int input = in.read();
+		synchronized (lock) {
+			readStartedMs = -1;
+		}
+		return input;
+	}
+
+	@Override
+	public int read(byte[] b) throws IOException {
+		return read(b, 0, b.length);
+	}
+
+	@Override
+	public int read(byte[] b, int off, int len) throws IOException {
+		synchronized (lock) {
+			readStartedMs = clock.currentTimeMillis();
+		}
+		int read = in.read(b, off, len);
+		synchronized (lock) {
+			readStartedMs = -1;
+		}
+		return read;
+	}
+
+	@Override
+	public void close() throws IOException {
+		try {
+			in.close();
+		} finally {
+			listener.onClose(this);
+		}
+	}
+
+	@Override
+	public int available() throws IOException {
+		return in.available();
+	}
+
+	@Override
+	public void mark(int readlimit) {
+		in.mark(readlimit);
+	}
+
+	@Override
+	public boolean markSupported() {
+		return in.markSupported();
+	}
+
+	@Override
+	public void reset() throws IOException {
+		in.reset();
+	}
+
+	@Override
+	public long skip(long n) throws IOException {
+		return in.skip(n);
+	}
+
+	boolean hasTimedOut() {
+		synchronized (lock) {
+			return readStartedMs != -1 &&
+					clock.currentTimeMillis() - readStartedMs > timeoutMs;
+		}
+	}
+
+	interface CloseListener {
+
+		void onClose(TimeoutInputStream closed);
+	}
+}

bramble-core/src/main/java/org/briarproject/bramble/io/TimeoutMonitorImpl.java

@@ -0,0 +1,96 @@
+package org.briarproject.bramble.io;
+
+import org.briarproject.bramble.api.io.TimeoutMonitor;
+import org.briarproject.bramble.api.lifecycle.IoExecutor;
+import org.briarproject.bramble.api.system.Clock;
+import org.briarproject.bramble.api.system.Scheduler;
+
+import java.io.IOException;
+import java.io.InputStream;
+import java.util.ArrayList;
+import java.util.List;
+import java.util.concurrent.Executor;
+import java.util.concurrent.Future;
+import java.util.concurrent.ScheduledExecutorService;
+import java.util.logging.Logger;
+
+import javax.annotation.concurrent.GuardedBy;
+import javax.inject.Inject;
+
+import static java.util.concurrent.TimeUnit.MILLISECONDS;
+import static java.util.concurrent.TimeUnit.SECONDS;
+import static java.util.logging.Level.INFO;
+import static java.util.logging.Logger.getLogger;
+import static org.briarproject.bramble.util.LogUtils.logException;
+
+class TimeoutMonitorImpl implements TimeoutMonitor {
+
+	private static final Logger LOG =
+			getLogger(TimeoutMonitorImpl.class.getName());
+
+	private static final long CHECK_INTERVAL_MS = SECONDS.toMillis(10);
+
+	private final ScheduledExecutorService scheduler;
+	private final Executor ioExecutor;
+	private final Clock clock;
+	private final Object lock = new Object();
+	@GuardedBy("lock")
+	private final List<TimeoutInputStream> streams = new ArrayList<>();
+
+	@GuardedBy("lock")
+	private Future<?> task = null;
+
+	@Inject
+	TimeoutMonitorImpl(@Scheduler ScheduledExecutorService scheduler,
+			@IoExecutor Executor ioExecutor, Clock clock) {
+		this.scheduler = scheduler;
+		this.ioExecutor = ioExecutor;
+		this.clock = clock;
+	}
+
+	@Override
+	public InputStream createTimeoutInputStream(InputStream in,
+			long timeoutMs) {
+		TimeoutInputStream stream = new TimeoutInputStream(clock, in,
+				timeoutMs, this::removeStream);
+		synchronized (lock) {
+			if (streams.isEmpty()) {
+				task = scheduler.scheduleWithFixedDelay(this::checkTimeouts,
+						CHECK_INTERVAL_MS, CHECK_INTERVAL_MS, MILLISECONDS);
+			}
+			streams.add(stream);
+		}
+		return stream;
+	}
+
+	private void removeStream(TimeoutInputStream stream) {
+		Future<?> toCancel = null;
+		synchronized (lock) {
+			if (streams.remove(stream) && streams.isEmpty()) {
+				toCancel = task;
+				task = null;
+			}
+		}
+		if (toCancel != null) toCancel.cancel(false);
+	}
+
+	@Scheduler
+	private void checkTimeouts() {
+		ioExecutor.execute(() -> {
+			List<TimeoutInputStream> snapshot;
+			synchronized (lock) {
+				snapshot = new ArrayList<>(streams);
+			}
+			for (TimeoutInputStream stream : snapshot) {
+				if (stream.hasTimedOut()) {
+					LOG.info("Input stream has timed out");
+					try {
+						stream.close();
+					} catch (IOException e) {
+						logException(LOG, INFO, e);
+					}
+				}
+			}
+		});
+	}
+}

bramble-core/src/main/java/org/briarproject/bramble/plugin/ConnectionManagerImpl.java

@@ -15,6 +15,8 @@ import org.briarproject.bramble.api.plugin.TransportConnectionReader;
 import org.briarproject.bramble.api.plugin.TransportConnectionWriter;
 import org.briarproject.bramble.api.plugin.TransportId;
 import org.briarproject.bramble.api.plugin.duplex.DuplexTransportConnection;
+import org.briarproject.bramble.api.properties.TransportProperties;
+import org.briarproject.bramble.api.properties.TransportPropertyManager;
 import org.briarproject.bramble.api.sync.SyncSession;
 import org.briarproject.bramble.api.sync.SyncSessionFactory;
 import org.briarproject.bramble.api.transport.KeyManager;
@@ -52,6 +54,7 @@ class ConnectionManagerImpl implements ConnectionManager {
 	private final HandshakeManager handshakeManager;
 	private final ContactExchangeManager contactExchangeManager;
 	private final ConnectionRegistry connectionRegistry;
+	private final TransportPropertyManager transportPropertyManager;
 
 	@Inject
 	ConnectionManagerImpl(@IoExecutor Executor ioExecutor,
@@ -60,7 +63,8 @@ class ConnectionManagerImpl implements ConnectionManager {
 			SyncSessionFactory syncSessionFactory,
 			HandshakeManager handshakeManager,
 			ContactExchangeManager contactExchangeManager,
-			ConnectionRegistry connectionRegistry) {
+			ConnectionRegistry connectionRegistry,
+			TransportPropertyManager transportPropertyManager) {
 		this.ioExecutor = ioExecutor;
 		this.keyManager = keyManager;
 		this.streamReaderFactory = streamReaderFactory;
@@ -69,6 +73,7 @@ class ConnectionManagerImpl implements ConnectionManager {
 		this.handshakeManager = handshakeManager;
 		this.contactExchangeManager = contactExchangeManager;
 		this.connectionRegistry = connectionRegistry;
+		this.transportPropertyManager = transportPropertyManager;
 	}
 
 	@Override
@@ -125,8 +130,8 @@ class ConnectionManagerImpl implements ConnectionManager {
 			TransportConnectionWriter w) throws IOException {
 		StreamWriter streamWriter = streamWriterFactory.createStreamWriter(
 				w.getOutputStream(), ctx);
-		ContactId c = requireNonNull(ctx.getContactId());
-		return syncSessionFactory.createSimplexOutgoingSession(c,
+		return syncSessionFactory.createSimplexOutgoingSession(
+				requireNonNull(ctx.getContactId()), ctx.getTransportId(),
 				w.getMaxLatency(), streamWriter);
 	}
 
@@ -134,8 +139,8 @@ class ConnectionManagerImpl implements ConnectionManager {
 			TransportConnectionWriter w) throws IOException {
 		StreamWriter streamWriter = streamWriterFactory.createStreamWriter(
 				w.getOutputStream(), ctx);
-		ContactId c = requireNonNull(ctx.getContactId());
-		return syncSessionFactory.createDuplexOutgoingSession(c,
+		return syncSessionFactory.createDuplexOutgoingSession(
+				requireNonNull(ctx.getContactId()), ctx.getTransportId(),
 				w.getMaxLatency(), w.getMaxIdleTime(), streamWriter);
 	}
 
@@ -269,6 +274,7 @@ class ConnectionManagerImpl implements ConnectionManager {
 		private final TransportId transportId;
 		private final TransportConnectionReader reader;
 		private final TransportConnectionWriter writer;
+		private final TransportProperties remote;
 
 		@Nullable
 		private volatile SyncSession outgoingSession = null;
@@ -278,6 +284,7 @@ class ConnectionManagerImpl implements ConnectionManager {
 			this.transportId = transportId;
 			reader = connection.getReader();
 			writer = connection.getWriter();
+			remote = connection.getRemoteProperties();
 		}
 
 		@Override
@@ -313,13 +320,16 @@ class ConnectionManagerImpl implements ConnectionManager {
 			// Start the outgoing session on another thread
 			ioExecutor.execute(() -> runOutgoingSession(contactId));
 			try {
+				// Store any transport properties discovered from the connection
+				transportPropertyManager.addRemotePropertiesFromConnection(
+						contactId, transportId, remote);
 				// Create and run the incoming session
 				createIncomingSession(ctx, reader).run();
 				reader.dispose(false, true);
 				// Interrupt the outgoing session so it finishes cleanly
 				SyncSession out = outgoingSession;
 				if (out != null) out.interrupt();
-			} catch (IOException e) {
+			} catch (DbException | IOException e) {
 				logException(LOG, WARNING, e);
 				onReadError(true);
 			} finally {
@@ -375,6 +385,7 @@ class ConnectionManagerImpl implements ConnectionManager {
 		private final TransportId transportId;
 		private final TransportConnectionReader reader;
 		private final TransportConnectionWriter writer;
+		private final TransportProperties remote;
 
 		@Nullable
 		private volatile SyncSession outgoingSession = null;
@@ -385,6 +396,7 @@ class ConnectionManagerImpl implements ConnectionManager {
 			this.transportId = transportId;
 			reader = connection.getReader();
 			writer = connection.getWriter();
+			remote = connection.getRemoteProperties();
 		}
 
 		@Override
@@ -461,13 +473,16 @@ class ConnectionManagerImpl implements ConnectionManager {
 			connectionRegistry.registerConnection(contactId, transportId,
 					false);
 			try {
+				// Store any transport properties discovered from the connection
+				transportPropertyManager.addRemotePropertiesFromConnection(
+						contactId, transportId, remote);
 				// Create and run the incoming session
 				createIncomingSession(ctx, reader).run();
 				reader.dispose(false, true);
 				// Interrupt the outgoing session so it finishes cleanly
 				SyncSession out = outgoingSession;
 				if (out != null) out.interrupt();
-			} catch (IOException e) {
+			} catch (DbException | IOException e) {
 				logException(LOG, WARNING, e);
 				onReadError();
 			} finally {

bramble-core/src/main/java/org/briarproject/bramble/plugin/PluginManagerImpl.java

@@ -8,7 +8,6 @@ import org.briarproject.bramble.api.lifecycle.ServiceException;
 import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
 import org.briarproject.bramble.api.plugin.ConnectionManager;
 import org.briarproject.bramble.api.plugin.Plugin;
-import org.briarproject.bramble.api.plugin.Plugin.State;
 import org.briarproject.bramble.api.plugin.PluginCallback;
 import org.briarproject.bramble.api.plugin.PluginConfig;
 import org.briarproject.bramble.api.plugin.PluginException;
@@ -19,9 +18,8 @@ import org.briarproject.bramble.api.plugin.TransportId;
 import org.briarproject.bramble.api.plugin.duplex.DuplexPlugin;
 import org.briarproject.bramble.api.plugin.duplex.DuplexPluginFactory;
 import org.briarproject.bramble.api.plugin.duplex.DuplexTransportConnection;
-import org.briarproject.bramble.api.plugin.event.TransportActiveEvent;
-import org.briarproject.bramble.api.plugin.event.TransportInactiveEvent;
-import org.briarproject.bramble.api.plugin.event.TransportStateEvent;
+import org.briarproject.bramble.api.plugin.event.TransportDisabledEvent;
+import org.briarproject.bramble.api.plugin.event.TransportEnabledEvent;
 import org.briarproject.bramble.api.plugin.simplex.SimplexPlugin;
 import org.briarproject.bramble.api.plugin.simplex.SimplexPluginFactory;
 import org.briarproject.bramble.api.properties.TransportProperties;
@@ -38,7 +36,6 @@ import java.util.concurrent.CopyOnWriteArrayList;
 import java.util.concurrent.CountDownLatch;
 import java.util.concurrent.Executor;
 import java.util.concurrent.atomic.AtomicBoolean;
-import java.util.concurrent.atomic.AtomicReference;
 import java.util.logging.Logger;
 
 import javax.annotation.concurrent.ThreadSafe;
@@ -48,9 +45,6 @@ import static java.util.logging.Level.FINE;
 import static java.util.logging.Level.INFO;
 import static java.util.logging.Level.WARNING;
 import static java.util.logging.Logger.getLogger;
-import static org.briarproject.bramble.api.plugin.Plugin.PREF_PLUGIN_ENABLE;
-import static org.briarproject.bramble.api.plugin.Plugin.State.ACTIVE;
-import static org.briarproject.bramble.api.plugin.Plugin.State.DISABLED;
 import static org.briarproject.bramble.util.LogUtils.logDuration;
 import static org.briarproject.bramble.util.LogUtils.logException;
 import static org.briarproject.bramble.util.LogUtils.now;
@@ -183,26 +177,6 @@ class PluginManagerImpl implements PluginManager, Service {
 		return supported;
 	}
 
-	@Override
-	public void setPluginEnabled(TransportId t, boolean enabled) {
-		Plugin plugin = plugins.get(t);
-		if (plugin == null) return;
-
-		Settings s = new Settings();
-		s.putBoolean(PREF_PLUGIN_ENABLE, enabled);
-		ioExecutor.execute(() -> mergeSettings(s, t.getString()));
-	}
-
-	private void mergeSettings(Settings s, String namespace) {
-		try {
-			long start = now();
-			settingsManager.mergeSettings(s, namespace);
-			logDuration(LOG, "Merging settings", start);
-		} catch (DbException e) {
-			logException(LOG, WARNING, e);
-		}
-	}
-
 	private class PluginStarter implements Runnable {
 
 		private final Plugin plugin;
@@ -276,8 +250,7 @@ class PluginManagerImpl implements PluginManager, Service {
 	private class Callback implements PluginCallback {
 
 		private final TransportId id;
-		private final AtomicReference<State> state =
-				new AtomicReference<>(DISABLED);
+		private final AtomicBoolean enabled = new AtomicBoolean(false);
 
 		private Callback(TransportId id) {
 			this.id = id;
@@ -305,7 +278,11 @@ class PluginManagerImpl implements PluginManager, Service {
 
 		@Override
 		public void mergeSettings(Settings s) {
-			PluginManagerImpl.this.mergeSettings(s, id.getString());
+			try {
+				settingsManager.mergeSettings(s, id.getString());
+			} catch (DbException e) {
+				logException(LOG, WARNING, e);
+			}
 		}
 
 		@Override
@@ -318,20 +295,15 @@ class PluginManagerImpl implements PluginManager, Service {
 		}
 
 		@Override
-		public void pluginStateChanged(State newState) {
-			State oldState = state.getAndSet(newState);
-			if (newState != oldState) {
-				if (LOG.isLoggable(INFO)) {
-					LOG.info(id + " changed from state " + oldState
-							+ " to " + newState);
-				}
-				eventBus.broadcast(new TransportStateEvent(id, newState));
-				if (newState == ACTIVE) {
-					eventBus.broadcast(new TransportActiveEvent(id));
-				} else if (oldState == ACTIVE) {
-					eventBus.broadcast(new TransportInactiveEvent(id));
-				}
-			}
+		public void transportEnabled() {
+			if (!enabled.getAndSet(true))
+				eventBus.broadcast(new TransportEnabledEvent(id));
+		}
+
+		@Override
+		public void transportDisabled() {
+			if (enabled.getAndSet(false))
+				eventBus.broadcast(new TransportDisabledEvent(id));
 		}
 
 		@Override

bramble-core/src/main/java/org/briarproject/bramble/plugin/PollerImpl.java

@@ -20,8 +20,8 @@ import org.briarproject.bramble.api.plugin.duplex.DuplexPlugin;
 import org.briarproject.bramble.api.plugin.duplex.DuplexTransportConnection;
 import org.briarproject.bramble.api.plugin.event.ConnectionClosedEvent;
 import org.briarproject.bramble.api.plugin.event.ConnectionOpenedEvent;
-import org.briarproject.bramble.api.plugin.event.TransportActiveEvent;
-import org.briarproject.bramble.api.plugin.event.TransportInactiveEvent;
+import org.briarproject.bramble.api.plugin.event.TransportDisabledEvent;
+import org.briarproject.bramble.api.plugin.event.TransportEnabledEvent;
 import org.briarproject.bramble.api.plugin.simplex.SimplexPlugin;
 import org.briarproject.bramble.api.properties.TransportProperties;
 import org.briarproject.bramble.api.properties.TransportPropertyManager;
@@ -106,13 +106,13 @@ class PollerImpl implements Poller, EventListener {
 			ConnectionOpenedEvent c = (ConnectionOpenedEvent) e;
 			// Reschedule polling, the polling interval may have decreased
 			reschedule(c.getTransportId());
-		} else if (e instanceof TransportActiveEvent) {
-			TransportActiveEvent t = (TransportActiveEvent) e;
-			// Poll the newly activated transport
+		} else if (e instanceof TransportEnabledEvent) {
+			TransportEnabledEvent t = (TransportEnabledEvent) e;
+			// Poll the newly enabled transport
 			pollNow(t.getTransportId());
-		} else if (e instanceof TransportInactiveEvent) {
-			TransportInactiveEvent t = (TransportInactiveEvent) e;
-			// Cancel polling for the deactivated transport
+		} else if (e instanceof TransportDisabledEvent) {
+			TransportDisabledEvent t = (TransportDisabledEvent) e;
+			// Cancel polling for the disabled transport
 			cancel(t.getTransportId());
 		}
 	}

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

@@ -3,9 +3,30 @@ package org.briarproject.bramble.plugin.bluetooth;
 import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
 import org.briarproject.bramble.api.plugin.duplex.DuplexTransportConnection;
 
+import static java.util.concurrent.TimeUnit.DAYS;
+import static java.util.concurrent.TimeUnit.MINUTES;
+import static java.util.concurrent.TimeUnit.SECONDS;
+
 @NotNullByDefault
 interface BluetoothConnectionLimiter {
 
+	/**
+	 * How long a connection must remain open before it's considered stable.
+	 */
+	long STABILITY_PERIOD_MS = SECONDS.toMillis(90);
+
+	/**
+	 * The minimum interval between attempts to raise the connection limit.
+	 * This is longer than {@link #STABILITY_PERIOD_MS} so we don't start
+	 * another attempt before knowing the outcome of the last one.
+	 */
+	long MIN_ATTEMPT_INTERVAL_MS = MINUTES.toMillis(2);
+
+	/**
+	 * The maximum interval between attempts to raise the connection limit.
+	 */
+	long MAX_ATTEMPT_INTERVAL_MS = DAYS.toMillis(2);
+
 	/**
 	 * Informs the limiter that key agreement has started.
 	 */
@@ -23,12 +44,12 @@ interface BluetoothConnectionLimiter {
 	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.
+	 * Informs the limiter that a contact connection has been opened.
 	 * <p/>
-	 * Returns false if the limiter has closed the new connection.
+	 * Returns true if the connection is allowed.
 	 */
-	boolean contactConnectionOpened(DuplexTransportConnection conn);
+	boolean contactConnectionOpened(DuplexTransportConnection conn,
+			boolean incoming);
 
 	/**
 	 * Informs the limiter that a key agreement connection has been opened.
@@ -37,11 +58,13 @@ interface BluetoothConnectionLimiter {
 
 	/**
 	 * Informs the limiter that the given connection has been closed.
+	 *
+	 * @param exception True if the connection was closed due to an exception.
 	 */
-	void connectionClosed(DuplexTransportConnection conn);
+	void connectionClosed(DuplexTransportConnection conn, boolean exception);
 
 	/**
-	 * Informs the limiter that all connections have been closed.
+	 * Informs the limiter that the Bluetooth adapter has been disabled.
 	 */
-	void allConnectionsClosed();
+	void bluetoothDisabled();
 }

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

@@ -1,46 +1,59 @@
 package org.briarproject.bramble.plugin.bluetooth;
 
+import org.briarproject.bramble.api.event.EventBus;
 import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
 import org.briarproject.bramble.api.plugin.duplex.DuplexTransportConnection;
+import org.briarproject.bramble.api.sync.event.CloseSyncConnectionsEvent;
+import org.briarproject.bramble.api.system.Clock;
 
-import java.io.IOException;
-import java.util.ArrayList;
+import java.util.Iterator;
 import java.util.LinkedList;
 import java.util.List;
 import java.util.logging.Logger;
 
+import javax.annotation.concurrent.GuardedBy;
 import javax.annotation.concurrent.ThreadSafe;
+import javax.inject.Inject;
 
+import static java.lang.Math.min;
 import static java.util.logging.Level.INFO;
-import static java.util.logging.Level.WARNING;
-import static org.briarproject.bramble.util.LogUtils.logException;
+import static java.util.logging.Logger.getLogger;
+import static org.briarproject.bramble.api.plugin.BluetoothConstants.ID;
 
 @NotNullByDefault
 @ThreadSafe
 class BluetoothConnectionLimiterImpl implements BluetoothConnectionLimiter {
 
 	private static final Logger LOG =
-			Logger.getLogger(BluetoothConnectionLimiterImpl.class.getName());
+			getLogger(BluetoothConnectionLimiterImpl.class.getName());
+
+	private final EventBus eventBus;
+	private final Clock clock;
 
 	private final Object lock = new Object();
-	// The following are locking: lock
-	private final LinkedList<DuplexTransportConnection> connections =
-			new LinkedList<>();
+	@GuardedBy("lock")
+	private final List<ConnectionRecord> connections = new LinkedList<>();
+	@GuardedBy("lock")
 	private boolean keyAgreementInProgress = false;
+	@GuardedBy("lock")
+	private int connectionLimit = 1;
+	@GuardedBy("lock")
+	private long timeOfLastAttempt = 0,
+			attemptInterval = MIN_ATTEMPT_INTERVAL_MS;
+
+	@Inject
+	BluetoothConnectionLimiterImpl(EventBus eventBus, Clock clock) {
+		this.eventBus = eventBus;
+		this.clock = clock;
+	}
 
 	@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);
+		LOG.info("Key agreement started");
+		eventBus.broadcast(new CloseSyncConnectionsEvent(ID));
 	}
 
 	@Override
@@ -55,62 +68,128 @@ class BluetoothConnectionLimiterImpl implements BluetoothConnectionLimiter {
 	public boolean canOpenContactConnection() {
 		synchronized (lock) {
 			if (keyAgreementInProgress) {
-				LOG.info("Can't open contact connection during key agreement");
+				LOG.info("Refusing contact connection during key agreement");
 				return false;
 			} else {
-				LOG.info("Can open contact connection");
-				return true;
+				long now = clock.currentTimeMillis();
+				return isContactConnectionAllowedByLimit(now);
 			}
 		}
 	}
 
 	@Override
-	public boolean contactConnectionOpened(DuplexTransportConnection conn) {
-		boolean accept = true;
+	public boolean contactConnectionOpened(DuplexTransportConnection conn,
+			boolean incoming) {
 		synchronized (lock) {
 			if (keyAgreementInProgress) {
 				LOG.info("Refusing contact connection during key agreement");
-				accept = false;
+				return false;
 			} else {
-				LOG.info("Accepting contact connection");
-				connections.add(conn);
+				long now = clock.currentTimeMillis();
+				if (incoming || isContactConnectionAllowedByLimit(now)) {
+					connections.add(new ConnectionRecord(conn, now));
+					if (!incoming && connections.size() > connectionLimit) {
+						LOG.info("Attempting to raise connection limit");
+						timeOfLastAttempt = now;
+					}
+					return true;
+				} else {
+					return false;
+				}
 			}
 		}
-		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) {
-			logException(LOG, WARNING, e);
+			connections.add(
+					new ConnectionRecord(conn, clock.currentTimeMillis()));
 		}
 	}
 
 	@Override
-	public void connectionClosed(DuplexTransportConnection conn) {
+	public void connectionClosed(DuplexTransportConnection conn,
+			boolean exception) {
 		synchronized (lock) {
-			connections.remove(conn);
+			Iterator<ConnectionRecord> it = connections.iterator();
+			while (it.hasNext()) {
+				if (it.next().connection == conn) {
+					long now = clock.currentTimeMillis();
+					if (exception) connectionFailed(now);
+					else considerRaisingConnectionLimit(now);
+					it.remove();
+					break;
+				}
+			}
 			if (LOG.isLoggable(INFO))
 				LOG.info("Connection closed, " + connections.size() + " open");
 		}
 	}
 
 	@Override
-	public void allConnectionsClosed() {
+	public void bluetoothDisabled() {
 		synchronized (lock) {
+			LOG.info("Bluetooth disabled");
+			considerRaisingConnectionLimit(clock.currentTimeMillis());
 			connections.clear();
-			LOG.info("All connections closed");
+		}
+	}
+
+	@GuardedBy("lock")
+	private boolean isContactConnectionAllowedByLimit(long now) {
+		considerRaisingConnectionLimit(now);
+		if (connections.size() > connectionLimit) {
+			LOG.info("Refusing contact connection, above limit");
+			return false;
+		} else if (connections.size() < connectionLimit) {
+			LOG.info("Allowing contact connection, below limit");
+			return true;
+		} else if (now - timeOfLastAttempt >= attemptInterval) {
+			LOG.info("Allowing contact connection, at limit");
+			return true;
+		} else {
+			LOG.info("Refusing contact connection, at limit");
+			return false;
+		}
+	}
+
+	@GuardedBy("lock")
+	private void considerRaisingConnectionLimit(long now) {
+		int stable = 0;
+		for (ConnectionRecord rec : connections) {
+			if (now - rec.timeOpened >= STABILITY_PERIOD_MS) stable++;
+		}
+		if (stable > connectionLimit) {
+			LOG.info("Raising connection limit");
+			connectionLimit = stable;
+			attemptInterval = MIN_ATTEMPT_INTERVAL_MS;
+		}
+		if (LOG.isLoggable(INFO)) {
+			LOG.info(stable + " connections are stable, limit is "
+					+ connectionLimit);
+		}
+	}
+
+	@GuardedBy("lock")
+	private void connectionFailed(long now) {
+		if (connections.size() > connectionLimit &&
+				now - timeOfLastAttempt < STABILITY_PERIOD_MS) {
+			LOG.info("Connection failed above limit, increasing interval");
+			attemptInterval = min(attemptInterval * 2, MAX_ATTEMPT_INTERVAL_MS);
+		}
+	}
+
+	private static final class ConnectionRecord {
+
+		private final DuplexTransportConnection connection;
+		private final long timeOpened;
+
+		private ConnectionRecord(DuplexTransportConnection connection,
+				long timeOpened) {
+			this.connection = connection;
+			this.timeOpened = timeOpened;
 		}
 	}
 }

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

@@ -5,13 +5,12 @@ import org.briarproject.bramble.api.Pair;
 import org.briarproject.bramble.api.data.BdfList;
 import org.briarproject.bramble.api.event.Event;
 import org.briarproject.bramble.api.event.EventListener;
+import org.briarproject.bramble.api.io.TimeoutMonitor;
 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.lifecycle.IoExecutor;
 import org.briarproject.bramble.api.nullsafety.MethodsNotNullByDefault;
-import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
 import org.briarproject.bramble.api.nullsafety.ParametersNotNullByDefault;
 import org.briarproject.bramble.api.plugin.Backoff;
 import org.briarproject.bramble.api.plugin.ConnectionHandler;
@@ -38,21 +37,16 @@ import java.util.concurrent.atomic.AtomicBoolean;
 import java.util.logging.Logger;
 
 import javax.annotation.Nullable;
-import javax.annotation.concurrent.GuardedBy;
-import javax.annotation.concurrent.ThreadSafe;
 
 import static java.util.logging.Level.INFO;
 import static java.util.logging.Level.WARNING;
 import static java.util.logging.Logger.getLogger;
 import static org.briarproject.bramble.api.keyagreement.KeyAgreementConstants.TRANSPORT_ID_BLUETOOTH;
 import static org.briarproject.bramble.api.plugin.BluetoothConstants.ID;
+import static org.briarproject.bramble.api.plugin.BluetoothConstants.PREF_BT_ENABLE;
 import static org.briarproject.bramble.api.plugin.BluetoothConstants.PROP_ADDRESS;
 import static org.briarproject.bramble.api.plugin.BluetoothConstants.PROP_UUID;
-import static org.briarproject.bramble.api.plugin.BluetoothConstants.REASON_NO_BT_ADAPTER;
 import static org.briarproject.bramble.api.plugin.BluetoothConstants.UUID_BYTES;
-import static org.briarproject.bramble.api.plugin.Plugin.State.ACTIVE;
-import static org.briarproject.bramble.api.plugin.Plugin.State.DISABLED;
-import static org.briarproject.bramble.api.plugin.Plugin.State.INACTIVE;
 import static org.briarproject.bramble.util.LogUtils.logException;
 import static org.briarproject.bramble.util.PrivacyUtils.scrubMacAddress;
 import static org.briarproject.bramble.util.StringUtils.isNullOrEmpty;
@@ -67,17 +61,18 @@ abstract class BluetoothPlugin<SS> implements DuplexPlugin, EventListener {
 			getLogger(BluetoothPlugin.class.getName());
 
 	final BluetoothConnectionLimiter connectionLimiter;
+	final TimeoutMonitor timeoutMonitor;
 
 	private final Executor ioExecutor;
 	private final SecureRandom secureRandom;
 	private final Backoff backoff;
 	private final PluginCallback callback;
-	private final int maxLatency;
+	private final int maxLatency, maxIdleTime;
 	private final AtomicBoolean used = new AtomicBoolean(false);
 
-	protected final PluginState state = new PluginState();
-
+	private volatile boolean running = false, contactConnections = false;
 	private volatile String contactConnectionsUuid = null;
+	private volatile SS socket = null;
 
 	abstract void initialiseAdapter() throws IOException;
 
@@ -112,32 +107,31 @@ abstract class BluetoothPlugin<SS> implements DuplexPlugin, EventListener {
 	abstract DuplexTransportConnection discoverAndConnect(String uuid);
 
 	BluetoothPlugin(BluetoothConnectionLimiter connectionLimiter,
-			Executor ioExecutor, SecureRandom secureRandom,
-			Backoff backoff, PluginCallback callback, int maxLatency) {
+			TimeoutMonitor timeoutMonitor, Executor ioExecutor,
+			SecureRandom secureRandom, Backoff backoff,
+			PluginCallback callback, int maxLatency, int maxIdleTime) {
 		this.connectionLimiter = connectionLimiter;
+		this.timeoutMonitor = timeoutMonitor;
 		this.ioExecutor = ioExecutor;
 		this.secureRandom = secureRandom;
 		this.backoff = backoff;
 		this.callback = callback;
 		this.maxLatency = maxLatency;
+		this.maxIdleTime = maxIdleTime;
 	}
 
 	void onAdapterEnabled() {
 		LOG.info("Bluetooth enabled");
 		// We may not have been able to get the local address before
 		ioExecutor.execute(this::updateProperties);
-		if (getState() == INACTIVE) bind();
+		if (shouldAllowContactConnections()) bind();
 	}
 
 	void onAdapterDisabled() {
 		LOG.info("Bluetooth disabled");
-		connectionLimiter.allConnectionsClosed();
-		// The server socket may not have been closed automatically
-		SS ss = state.clearServerSocket();
-		if (ss != null) {
-			LOG.info("Closing server socket");
-			tryToClose(ss);
-		}
+		tryToClose(socket);
+		connectionLimiter.bluetoothDisabled();
+		callback.transportDisabled();
 	}
 
 	@Override
@@ -152,8 +146,7 @@ abstract class BluetoothPlugin<SS> implements DuplexPlugin, EventListener {
 
 	@Override
 	public int getMaxIdleTime() {
-		// Bluetooth detects dead connections so we don't need keepalives
-		return Integer.MAX_VALUE;
+		return maxIdleTime;
 	}
 
 	@Override
@@ -162,22 +155,28 @@ abstract class BluetoothPlugin<SS> implements DuplexPlugin, EventListener {
 		try {
 			initialiseAdapter();
 		} catch (IOException e) {
-			state.setNoAdapter();
 			throw new PluginException(e);
 		}
 		updateProperties();
-		Settings settings = callback.getSettings();
-		boolean enabledByUser = settings.getBoolean(PREF_PLUGIN_ENABLE, false);
-		state.setStarted(enabledByUser);
-		if (enabledByUser) {
+		running = true;
+		loadSettings(callback.getSettings());
+		if (shouldAllowContactConnections()) {
 			if (isAdapterEnabled()) bind();
 			else enableAdapter();
 		}
 	}
 
+	private void loadSettings(Settings settings) {
+		contactConnections = settings.getBoolean(PREF_BT_ENABLE, false);
+	}
+
+	private boolean shouldAllowContactConnections() {
+		return contactConnections;
+	}
+
 	private void bind() {
 		ioExecutor.execute(() -> {
-			if (getState() != INACTIVE) return;
+			if (!isRunning() || !shouldAllowContactConnections()) return;
 			// Bind a server socket to accept connections from contacts
 			SS ss;
 			try {
@@ -186,13 +185,14 @@ abstract class BluetoothPlugin<SS> implements DuplexPlugin, EventListener {
 				logException(LOG, WARNING, e);
 				return;
 			}
-			if (!state.setServerSocket(ss)) {
-				LOG.info("Closing redundant server socket");
+			if (!isRunning() || !shouldAllowContactConnections()) {
 				tryToClose(ss);
 				return;
 			}
+			socket = ss;
 			backoff.reset();
-			acceptContactConnections(ss);
+			callback.transportEnabled();
+			acceptContactConnections();
 		});
 	}
 
@@ -221,39 +221,47 @@ abstract class BluetoothPlugin<SS> implements DuplexPlugin, EventListener {
 		if (changed) callback.mergeLocalProperties(p);
 	}
 
-	private void acceptContactConnections(SS ss) {
+	private void acceptContactConnections() {
 		while (true) {
 			DuplexTransportConnection conn;
 			try {
-				conn = acceptConnection(ss);
+				conn = acceptConnection(socket);
 			} catch (IOException e) {
-				// This is expected when the server socket is closed
-				LOG.info("Server socket closed");
-				state.clearServerSocket();
+				// This is expected when the socket is closed
+				if (LOG.isLoggable(INFO)) LOG.info(e.toString());
 				return;
 			}
 			LOG.info("Connection received");
-			backoff.reset();
-			if (connectionLimiter.contactConnectionOpened(conn))
+			if (connectionLimiter.contactConnectionOpened(conn, true)) {
+				backoff.reset();
 				callback.handleConnection(conn);
+			} else {
+				tryToClose(conn);
+			}
+			if (!running) return;
+		}
+	}
+
+	private void tryToClose(DuplexTransportConnection conn) {
+		try {
+			conn.getWriter().dispose(false);
+			conn.getReader().dispose(false, false);
+		} catch (IOException e) {
+			logException(LOG, WARNING, e);
 		}
 	}
 
 	@Override
 	public void stop() {
-		SS ss = state.setStopped();
-		tryToClose(ss);
+		running = false;
+		tryToClose(socket);
+		callback.transportDisabled();
 		disableAdapterIfEnabledByUs();
 	}
 
 	@Override
-	public State getState() {
-		return state.getState();
-	}
-
-	@Override
-	public int getReasonDisabled() {
-		return state.getReasonDisabled();
+	public boolean isRunning() {
+		return running && isAdapterEnabled();
 	}
 
 	@Override
@@ -269,7 +277,7 @@ abstract class BluetoothPlugin<SS> implements DuplexPlugin, EventListener {
 	@Override
 	public void poll(Collection<Pair<TransportProperties, ConnectionHandler>>
 			properties) {
-		if (getState() != ACTIVE) return;
+		if (!isRunning() || !shouldAllowContactConnections()) return;
 		backoff.increment();
 		for (Pair<TransportProperties, ConnectionHandler> p : properties) {
 			connect(p.getFirst(), p.getSecond());
@@ -282,13 +290,10 @@ abstract class BluetoothPlugin<SS> implements DuplexPlugin, EventListener {
 		String uuid = p.get(PROP_UUID);
 		if (isNullOrEmpty(uuid)) return;
 		ioExecutor.execute(() -> {
-			if (getState() != ACTIVE) return;
-			if (!connectionLimiter.canOpenContactConnection()) return;
 			DuplexTransportConnection d = createConnection(p);
 			if (d != null) {
 				backoff.reset();
-				if (connectionLimiter.contactConnectionOpened(d))
-					h.handleConnection(d);
+				h.handleConnection(d);
 			}
 		});
 	}
@@ -326,7 +331,7 @@ abstract class BluetoothPlugin<SS> implements DuplexPlugin, EventListener {
 
 	@Override
 	public DuplexTransportConnection createConnection(TransportProperties p) {
-		if (getState() != ACTIVE) return null;
+		if (!isRunning() || !shouldAllowContactConnections()) return null;
 		if (!connectionLimiter.canOpenContactConnection()) return null;
 		String address = p.get(PROP_ADDRESS);
 		if (isNullOrEmpty(address)) return null;
@@ -334,8 +339,12 @@ abstract class BluetoothPlugin<SS> implements DuplexPlugin, EventListener {
 		if (isNullOrEmpty(uuid)) return null;
 		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;
+		if (connectionLimiter.contactConnectionOpened(conn, false)) {
+			return conn;
+		} else {
+			tryToClose(conn);
+			return null;
+		}
 	}
 
 	@Override
@@ -345,7 +354,7 @@ abstract class BluetoothPlugin<SS> implements DuplexPlugin, EventListener {
 
 	@Override
 	public KeyAgreementListener createKeyAgreementListener(byte[] commitment) {
-		if (getState() != ACTIVE) return null;
+		if (!isRunning()) return null;
 		// No truncation necessary because COMMIT_LENGTH = 16
 		String uuid = UUID.nameUUIDFromBytes(commitment).toString();
 		if (LOG.isLoggable(INFO)) LOG.info("Key agreement UUID " + uuid);
@@ -357,7 +366,7 @@ abstract class BluetoothPlugin<SS> implements DuplexPlugin, EventListener {
 			logException(LOG, WARNING, e);
 			return null;
 		}
-		if (getState() != ACTIVE) {
+		if (!isRunning()) {
 			tryToClose(ss);
 			return null;
 		}
@@ -371,7 +380,7 @@ abstract class BluetoothPlugin<SS> implements DuplexPlugin, EventListener {
 	@Override
 	public DuplexTransportConnection createKeyAgreementConnection(
 			byte[] commitment, BdfList descriptor) {
-		if (getState() != ACTIVE) return null;
+		if (!isRunning()) return null;
 		// No truncation necessary because COMMIT_LENGTH = 16
 		String uuid = UUID.nameUUIDFromBytes(commitment).toString();
 		DuplexTransportConnection conn;
@@ -431,17 +440,17 @@ abstract class BluetoothPlugin<SS> implements DuplexPlugin, EventListener {
 		}
 	}
 
-	@IoExecutor
 	private void onSettingsUpdated(Settings settings) {
-		boolean enabledByUser = settings.getBoolean(PREF_PLUGIN_ENABLE, false);
-		SS ss = state.setEnabledByUser(enabledByUser);
-		State s = getState();
-		if (ss != null) {
-			LOG.info("Disabled by user, closing server socket");
-			tryToClose(ss);
+		boolean wasAllowed = shouldAllowContactConnections();
+		loadSettings(settings);
+		boolean isAllowed = shouldAllowContactConnections();
+		if (wasAllowed && !isAllowed) {
+			LOG.info("Contact connections disabled");
+			tryToClose(socket);
+			callback.transportDisabled();
 			disableAdapterIfEnabledByUs();
-		} else if (s == INACTIVE) {
-			LOG.info("Enabled by user, opening server socket");
+		} else if (!wasAllowed && isAllowed) {
+			LOG.info("Contact connections enabled");
 			if (isAdapterEnabled()) bind();
 			else enableAdapter();
 		}
@@ -469,77 +478,4 @@ abstract class BluetoothPlugin<SS> implements DuplexPlugin, EventListener {
 			tryToClose(ss);
 		}
 	}
-
-	@ThreadSafe
-	@NotNullByDefault
-	protected class PluginState {
-
-		@GuardedBy("this")
-		private boolean started = false,
-				stopped = false,
-				noAdapter = false,
-				enabledByUser = false;
-
-		@GuardedBy("this")
-		@Nullable
-		private SS serverSocket = null;
-
-		synchronized void setStarted(boolean enabledByUser) {
-			started = true;
-			this.enabledByUser = enabledByUser;
-			callback.pluginStateChanged(getState());
-		}
-
-		@Nullable
-		synchronized SS setStopped() {
-			stopped = true;
-			SS ss = serverSocket;
-			serverSocket = null;
-			callback.pluginStateChanged(getState());
-			return ss;
-		}
-
-		synchronized void setNoAdapter() {
-			noAdapter = true;
-			callback.pluginStateChanged(getState());
-		}
-
-		@Nullable
-		synchronized SS setEnabledByUser(boolean enabledByUser) {
-			this.enabledByUser = enabledByUser;
-			SS ss = null;
-			if (!enabledByUser) {
-				ss = serverSocket;
-				serverSocket = null;
-			}
-			callback.pluginStateChanged(getState());
-			return ss;
-		}
-
-		synchronized boolean setServerSocket(SS ss) {
-			if (stopped || serverSocket != null) return false;
-			serverSocket = ss;
-			callback.pluginStateChanged(getState());
-			return true;
-		}
-
-		@Nullable
-		synchronized SS clearServerSocket() {
-			SS ss = serverSocket;
-			serverSocket = null;
-			callback.pluginStateChanged(getState());
-			return ss;
-		}
-
-		synchronized State getState() {
-			if (!started || stopped || !enabledByUser) return DISABLED;
-			return serverSocket == null ? INACTIVE : ACTIVE;
-		}
-
-		synchronized int getReasonDisabled() {
-			if (noAdapter && !stopped) return REASON_NO_BT_ADAPTER;
-			if (!started || stopped) return REASON_STARTING_STOPPING;
-			return enabledByUser ? -1 : REASON_USER;
-		}
-	}
 }

bramble-core/src/main/java/org/briarproject/bramble/plugin/file/FilePlugin.java

@@ -16,7 +16,6 @@ import java.util.logging.Logger;
 import static java.util.logging.Level.WARNING;
 import static java.util.logging.Logger.getLogger;
 import static org.briarproject.bramble.api.plugin.FileConstants.PROP_PATH;
-import static org.briarproject.bramble.api.plugin.Plugin.State.ACTIVE;
 import static org.briarproject.bramble.util.LogUtils.logException;
 import static org.briarproject.bramble.util.StringUtils.isNullOrEmpty;
 
@@ -46,7 +45,7 @@ abstract class FilePlugin implements SimplexPlugin {
 
 	@Override
 	public TransportConnectionReader createReader(TransportProperties p) {
-		if (getState() != ACTIVE) return null;
+		if (!isRunning()) return null;
 		String path = p.get(PROP_PATH);
 		if (isNullOrEmpty(path)) return null;
 		try {
@@ -61,7 +60,7 @@ abstract class FilePlugin implements SimplexPlugin {
 
 	@Override
 	public TransportConnectionWriter createWriter(TransportProperties p) {
-		if (getState() != ACTIVE) return null;
+		if (!isRunning()) return null;
 		String path = p.get(PROP_PATH);
 		if (isNullOrEmpty(path)) return null;
 		try {

bramble-core/src/main/java/org/briarproject/bramble/plugin/tcp/LanTcpPlugin.java

@@ -11,22 +11,26 @@ import org.briarproject.bramble.api.plugin.TransportId;
 import org.briarproject.bramble.api.plugin.duplex.DuplexTransportConnection;
 import org.briarproject.bramble.api.properties.TransportProperties;
 import org.briarproject.bramble.api.settings.Settings;
+import org.briarproject.bramble.util.IoUtils;
 
 import java.io.IOException;
 import java.net.Inet4Address;
 import java.net.InetAddress;
 import java.net.InetSocketAddress;
+import java.net.InterfaceAddress;
 import java.net.ServerSocket;
 import java.net.Socket;
 import java.net.UnknownHostException;
 import java.util.ArrayList;
-import java.util.Comparator;
 import java.util.List;
+import java.util.Random;
 import java.util.concurrent.Executor;
 import java.util.logging.Logger;
 
+import javax.annotation.Nullable;
+
+import static java.lang.Integer.parseInt;
 import static java.util.Collections.addAll;
-import static java.util.Collections.emptyList;
 import static java.util.Collections.sort;
 import static java.util.logging.Level.INFO;
 import static java.util.logging.Level.WARNING;
@@ -35,8 +39,8 @@ import static org.briarproject.bramble.api.keyagreement.KeyAgreementConstants.TR
 import static org.briarproject.bramble.api.plugin.LanTcpConstants.ID;
 import static org.briarproject.bramble.api.plugin.LanTcpConstants.PREF_LAN_IP_PORTS;
 import static org.briarproject.bramble.api.plugin.LanTcpConstants.PROP_IP_PORTS;
+import static org.briarproject.bramble.api.plugin.LanTcpConstants.PROP_PORT;
 import static org.briarproject.bramble.util.ByteUtils.MAX_16_BIT_UNSIGNED;
-import static org.briarproject.bramble.util.IoUtils.tryToClose;
 import static org.briarproject.bramble.util.PrivacyUtils.scrubSocketAddress;
 import static org.briarproject.bramble.util.StringUtils.isNullOrEmpty;
 import static org.briarproject.bramble.util.StringUtils.join;
@@ -46,15 +50,36 @@ class LanTcpPlugin extends TcpPlugin {
 
 	private static final Logger LOG = getLogger(LanTcpPlugin.class.getName());
 
-	private static final LanAddressComparator ADDRESS_COMPARATOR =
-			new LanAddressComparator();
-
 	private static final int MAX_ADDRESSES = 4;
 	private static final String SEPARATOR = ",";
 
+	/**
+	 * The IP address of an Android device providing a wifi access point.
+	 */
+	protected static final InetAddress WIFI_AP_ADDRESS;
+
+	/**
+	 * The IP address of an Android device providing a wifi direct
+	 * legacy mode access point.
+	 */
+	protected static final InetAddress WIFI_DIRECT_AP_ADDRESS;
+
+	static {
+		try {
+			WIFI_AP_ADDRESS = InetAddress.getByAddress(
+					new byte[] {(byte) 192, (byte) 168, 43, 1});
+			WIFI_DIRECT_AP_ADDRESS = InetAddress.getByAddress(
+					new byte[] {(byte) 192, (byte) 168, 49, 1});
+		} catch (UnknownHostException e) {
+			// Should only be thrown if the address has an illegal length
+			throw new AssertionError(e);
+		}
+	}
+
 	LanTcpPlugin(Executor ioExecutor, Backoff backoff, PluginCallback callback,
-			int maxLatency, int maxIdleTime) {
-		super(ioExecutor, backoff, callback, maxLatency, maxIdleTime);
+			int maxLatency, int maxIdleTime, int connectionTimeout) {
+		super(ioExecutor, backoff, callback, maxLatency, maxIdleTime,
+				connectionTimeout);
 	}
 
 	@Override
@@ -63,37 +88,81 @@ class LanTcpPlugin extends TcpPlugin {
 	}
 
 	@Override
-	protected List<InetSocketAddress> getLocalSocketAddresses() {
-		// Use the same address and port as last time if available
+	public void start() {
+		if (used.getAndSet(true)) throw new IllegalStateException();
+		initialisePortProperty();
+		running = true;
+		bind();
+	}
+
+	protected void initialisePortProperty() {
 		TransportProperties p = callback.getLocalProperties();
+		if (isNullOrEmpty(p.get(PROP_PORT))) {
+			int port = new Random().nextInt(32768) + 32768;
+			p.put(PROP_PORT, String.valueOf(port));
+			callback.mergeLocalProperties(p);
+		}
+	}
+
+	@Override
+	protected List<InetSocketAddress> getLocalSocketAddresses() {
+		TransportProperties p = callback.getLocalProperties();
+		int preferredPort = parsePortProperty(p.get(PROP_PORT));
 		String oldIpPorts = p.get(PROP_IP_PORTS);
 		List<InetSocketAddress> olds = parseSocketAddresses(oldIpPorts);
+
 		List<InetSocketAddress> locals = new ArrayList<>();
-		for (InetAddress local : getLocalIpAddresses()) {
-			if (isAcceptableAddress(local)) {
-				// If this is the old address, try to use the same port
-				for (InetSocketAddress old : olds) {
-					if (old.getAddress().equals(local))
-						locals.add(new InetSocketAddress(local, old.getPort()));
+		List<InetSocketAddress> fallbacks = new ArrayList<>();
+		for (InetAddress local : getUsableLocalInetAddresses()) {
+			// If we've used this address before, try to use the same port
+			int port = preferredPort;
+			for (InetSocketAddress old : olds) {
+				if (old.getAddress().equals(local)) {
+					port = old.getPort();
+					break;
 				}
-				locals.add(new InetSocketAddress(local, 0));
 			}
+			locals.add(new InetSocketAddress(local, port));
+			// Fall back to any available port
+			fallbacks.add(new InetSocketAddress(local, 0));
 		}
-		sort(locals, ADDRESS_COMPARATOR);
+		locals.addAll(fallbacks);
 		return locals;
 	}
 
+	private int parsePortProperty(@Nullable String portProperty) {
+		if (isNullOrEmpty(portProperty)) return 0;
+		try {
+			return parseInt(portProperty);
+		} catch (NumberFormatException e) {
+			return 0;
+		}
+	}
+
 	private List<InetSocketAddress> parseSocketAddresses(String ipPorts) {
-		if (isNullOrEmpty(ipPorts)) return emptyList();
-		String[] split = ipPorts.split(SEPARATOR);
 		List<InetSocketAddress> addresses = new ArrayList<>();
-		for (String ipPort : split) {
+		if (isNullOrEmpty(ipPorts)) return addresses;
+		for (String ipPort : ipPorts.split(SEPARATOR)) {
 			InetSocketAddress a = parseSocketAddress(ipPort);
 			if (a != null) addresses.add(a);
 		}
 		return addresses;
 	}
 
+	protected List<InetAddress> getUsableLocalInetAddresses() {
+		List<InterfaceAddress> ifAddrs =
+				new ArrayList<>(getLocalInterfaceAddresses());
+		// Prefer longer network prefixes
+		sort(ifAddrs, (a, b) ->
+				b.getNetworkPrefixLength() - a.getNetworkPrefixLength());
+		List<InetAddress> addrs = new ArrayList<>();
+		for (InterfaceAddress ifAddr : ifAddrs) {
+			InetAddress addr = ifAddr.getAddress();
+			if (isAcceptableAddress(addr)) addrs.add(addr);
+		}
+		return addrs;
+	}
+
 	@Override
 	protected void setLocalSocketAddress(InetSocketAddress a) {
 		String ipPort = getIpPortString(a);
@@ -131,7 +200,20 @@ class LanTcpPlugin extends TcpPlugin {
 	@Override
 	protected List<InetSocketAddress> getRemoteSocketAddresses(
 			TransportProperties p) {
-		return parseSocketAddresses(p.get(PROP_IP_PORTS));
+		String ipPorts = p.get(PROP_IP_PORTS);
+		List<InetSocketAddress> remotes = parseSocketAddresses(ipPorts);
+		int port = parsePortProperty(p.get(PROP_PORT));
+		// If the contact has a preferred port, we can guess their IP:port when
+		// they're providing a wifi access point
+		if (port != 0) {
+			InetSocketAddress wifiAp =
+					new InetSocketAddress(WIFI_AP_ADDRESS, port);
+			if (!remotes.contains(wifiAp)) remotes.add(wifiAp);
+			InetSocketAddress wifiDirectAp =
+					new InetSocketAddress(WIFI_DIRECT_AP_ADDRESS, port);
+			if (!remotes.contains(wifiDirectAp)) remotes.add(wifiDirectAp);
+		}
+		return remotes;
 	}
 
 	private boolean isAcceptableAddress(InetAddress a) {
@@ -144,53 +226,33 @@ class LanTcpPlugin extends TcpPlugin {
 	}
 
 	@Override
-	protected boolean isConnectable(InetSocketAddress remote) {
+	protected boolean isConnectable(InterfaceAddress local,
+			InetSocketAddress remote) {
 		if (remote.getPort() == 0) return false;
 		if (!isAcceptableAddress(remote.getAddress())) return false;
 		// Try to determine whether the address is on the same LAN as us
-		ServerSocket ss = state.getServerSocket();
-		if (ss == null) return false;
-		byte[] localIp = ss.getInetAddress().getAddress();
+		byte[] localIp = local.getAddress().getAddress();
 		byte[] remoteIp = remote.getAddress().getAddress();
-		return addressesAreOnSameLan(localIp, remoteIp);
+		int prefixLength = local.getNetworkPrefixLength();
+		return areAddressesInSameNetwork(localIp, remoteIp, prefixLength);
 	}
 
 	// Package access for testing
-	boolean addressesAreOnSameLan(byte[] localIp, byte[] remoteIp) {
-		// 10.0.0.0/8
-		if (isPrefix10(localIp)) return isPrefix10(remoteIp);
-		// 172.16.0.0/12
-		if (isPrefix172(localIp)) return isPrefix172(remoteIp);
-		// 192.168.0.0/16
-		if (isPrefix192(localIp)) return isPrefix192(remoteIp);
-		// Unrecognised prefix - may be compatible
+	static boolean areAddressesInSameNetwork(byte[] localIp, byte[] remoteIp,
+			int prefixLength) {
+		if (localIp.length != remoteIp.length) return false;
+		// Compare the first prefixLength bits of the addresses
+		for (int i = 0; i < prefixLength; i++) {
+			int byteIndex = i >> 3;
+			int bitIndex = i & 7; // 0 to 7
+			int mask = 128 >> bitIndex; // Select the bit at bitIndex
+			if ((localIp[byteIndex] & mask) != (remoteIp[byteIndex] & mask)) {
+				return false; // Addresses differ at bit i
+			}
+		}
 		return true;
 	}
 
-	private static boolean isPrefix10(byte[] ipv4) {
-		return ipv4[0] == 10;
-	}
-
-	private static boolean isPrefix172(byte[] ipv4) {
-		return ipv4[0] == (byte) 172 && (ipv4[1] & 0xF0) == 16;
-	}
-
-	private static boolean isPrefix192(byte[] ipv4) {
-		return ipv4[0] == (byte) 192 && ipv4[1] == (byte) 168;
-	}
-
-	// Returns the prefix length for an RFC 1918 address, or 0 for any other
-	// address
-	private static int getRfc1918PrefixLength(InetAddress addr) {
-		if (!(addr instanceof Inet4Address)) return 0;
-		if (!addr.isSiteLocalAddress()) return 0;
-		byte[] ipv4 = addr.getAddress();
-		if (isPrefix10(ipv4)) return 8;
-		if (isPrefix172(ipv4)) return 12;
-		if (isPrefix192(ipv4)) return 16;
-		return 0;
-	}
-
 	@Override
 	public boolean supportsKeyAgreement() {
 		return true;
@@ -209,10 +271,10 @@ class LanTcpPlugin extends TcpPlugin {
 			} catch (IOException e) {
 				if (LOG.isLoggable(INFO))
 					LOG.info("Failed to bind " + scrubSocketAddress(addr));
-				tryToClose(ss, LOG, WARNING);
+				tryToClose(ss);
 			}
 		}
-		if (ss == null) {
+		if (ss == null || !ss.isBound()) {
 			LOG.info("Could not bind server socket for key agreement");
 			return null;
 		}
@@ -228,8 +290,13 @@ class LanTcpPlugin extends TcpPlugin {
 	@Override
 	public DuplexTransportConnection createKeyAgreementConnection(
 			byte[] commitment, BdfList descriptor) {
-		ServerSocket ss = state.getServerSocket();
-		if (ss == null) return null;
+		if (!isRunning()) return null;
+		ServerSocket ss = socket;
+		InterfaceAddress local = getLocalInterfaceAddress(ss.getInetAddress());
+		if (local == null) {
+			LOG.warning("No interface for key agreement server socket");
+			return null;
+		}
 		InetSocketAddress remote;
 		try {
 			remote = parseSocketAddress(descriptor);
@@ -237,7 +304,7 @@ class LanTcpPlugin extends TcpPlugin {
 			LOG.info("Invalid IP/port in key agreement descriptor");
 			return null;
 		}
-		if (!isConnectable(remote)) {
+		if (!isConnectable(local, remote)) {
 			if (LOG.isLoggable(INFO)) {
 				LOG.info(scrubSocketAddress(remote) +
 						" is not connectable from " +
@@ -250,7 +317,7 @@ class LanTcpPlugin extends TcpPlugin {
 				LOG.info("Connecting to " + scrubSocketAddress(remote));
 			Socket s = createSocket();
 			s.bind(new InetSocketAddress(ss.getInetAddress(), 0));
-			s.connect(remote);
+			s.connect(remote, connectionTimeout);
 			s.setSoTimeout(socketTimeout);
 			if (LOG.isLoggable(INFO))
 				LOG.info("Connected to " + scrubSocketAddress(remote));
@@ -296,22 +363,7 @@ class LanTcpPlugin extends TcpPlugin {
 
 		@Override
 		public void close() {
-			tryToClose(ss, LOG, WARNING);
-		}
-	}
-
-	static class LanAddressComparator implements Comparator<InetSocketAddress> {
-
-		@Override
-		public int compare(InetSocketAddress a, InetSocketAddress b) {
-			// Prefer addresses with non-zero ports
-			int aPort = a.getPort(), bPort = b.getPort();
-			if (aPort > 0 && bPort == 0) return -1;
-			if (aPort == 0 && bPort > 0) return 1;
-			// Prefer addresses with longer RFC 1918 prefixes
-			int aPrefix = getRfc1918PrefixLength(a.getAddress());
-			int bPrefix = getRfc1918PrefixLength(b.getAddress());
-			return bPrefix - aPrefix;
+			IoUtils.tryToClose(ss, LOG, WARNING);
 		}
 	}
 }

bramble-core/src/main/java/org/briarproject/bramble/plugin/tcp/LanTcpPluginFactory.java

@@ -1,6 +1,5 @@
 package org.briarproject.bramble.plugin.tcp;
 
-import org.briarproject.bramble.api.event.EventBus;
 import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
 import org.briarproject.bramble.api.plugin.Backoff;
 import org.briarproject.bramble.api.plugin.BackoffFactory;
@@ -19,20 +18,19 @@ import static org.briarproject.bramble.api.plugin.LanTcpConstants.ID;
 @NotNullByDefault
 public class LanTcpPluginFactory implements DuplexPluginFactory {
 
-	private static final int MAX_LATENCY = 30 * 1000; // 30 seconds
-	private static final int MAX_IDLE_TIME = 30 * 1000; // 30 seconds
-	private static final int MIN_POLLING_INTERVAL = 60 * 1000; // 1 minute
-	private static final int MAX_POLLING_INTERVAL = 10 * 60 * 1000; // 10 mins
+	private static final int MAX_LATENCY = 30_000; // 30 seconds
+	private static final int MAX_IDLE_TIME = 30_000; // 30 seconds
+	private static final int CONNECTION_TIMEOUT = 3_000; // 3 seconds
+	private static final int MIN_POLLING_INTERVAL = 60_000; // 1 minute
+	private static final int MAX_POLLING_INTERVAL = 600_000; // 10 mins
 	private static final double BACKOFF_BASE = 1.2;
 
 	private final Executor ioExecutor;
-	private final EventBus eventBus;
 	private final BackoffFactory backoffFactory;
 
-	public LanTcpPluginFactory(Executor ioExecutor, EventBus eventBus,
+	public LanTcpPluginFactory(Executor ioExecutor,
 			BackoffFactory backoffFactory) {
 		this.ioExecutor = ioExecutor;
-		this.eventBus = eventBus;
 		this.backoffFactory = backoffFactory;
 	}
 
@@ -50,9 +48,7 @@ public class LanTcpPluginFactory implements DuplexPluginFactory {
 	public DuplexPlugin createPlugin(PluginCallback callback) {
 		Backoff backoff = backoffFactory.createBackoff(MIN_POLLING_INTERVAL,
 				MAX_POLLING_INTERVAL, BACKOFF_BASE);
-		LanTcpPlugin plugin = new LanTcpPlugin(ioExecutor, backoff, callback,
-				MAX_LATENCY, MAX_IDLE_TIME);
-		eventBus.addListener(plugin);
-		return plugin;
+		return new LanTcpPlugin(ioExecutor, backoff, callback, MAX_LATENCY,
+				MAX_IDLE_TIME, CONNECTION_TIMEOUT);
 	}
 }

bramble-core/src/main/java/org/briarproject/bramble/plugin/tcp/TcpPlugin.java

@@ -3,12 +3,8 @@ package org.briarproject.bramble.plugin.tcp;
 import org.briarproject.bramble.PoliteExecutor;
 import org.briarproject.bramble.api.Pair;
 import org.briarproject.bramble.api.data.BdfList;
-import org.briarproject.bramble.api.event.Event;
-import org.briarproject.bramble.api.event.EventListener;
 import org.briarproject.bramble.api.keyagreement.KeyAgreementListener;
-import org.briarproject.bramble.api.lifecycle.IoExecutor;
 import org.briarproject.bramble.api.nullsafety.MethodsNotNullByDefault;
-import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
 import org.briarproject.bramble.api.nullsafety.ParametersNotNullByDefault;
 import org.briarproject.bramble.api.plugin.Backoff;
 import org.briarproject.bramble.api.plugin.ConnectionHandler;
@@ -18,12 +14,12 @@ import org.briarproject.bramble.api.plugin.duplex.DuplexTransportConnection;
 import org.briarproject.bramble.api.properties.TransportProperties;
 import org.briarproject.bramble.api.rendezvous.KeyMaterialSource;
 import org.briarproject.bramble.api.rendezvous.RendezvousEndpoint;
-import org.briarproject.bramble.api.settings.Settings;
-import org.briarproject.bramble.api.settings.event.SettingsUpdatedEvent;
+import org.briarproject.bramble.util.IoUtils;
 
 import java.io.IOException;
 import java.net.InetAddress;
 import java.net.InetSocketAddress;
+import java.net.InterfaceAddress;
 import java.net.NetworkInterface;
 import java.net.ServerSocket;
 import java.net.Socket;
@@ -39,26 +35,19 @@ import java.util.logging.Logger;
 import java.util.regex.Pattern;
 
 import javax.annotation.Nullable;
-import javax.annotation.concurrent.GuardedBy;
-import javax.annotation.concurrent.ThreadSafe;
 
-import static java.net.NetworkInterface.getNetworkInterfaces;
 import static java.util.Collections.emptyList;
 import static java.util.Collections.list;
 import static java.util.logging.Level.INFO;
 import static java.util.logging.Level.WARNING;
 import static java.util.logging.Logger.getLogger;
-import static org.briarproject.bramble.api.plugin.Plugin.State.ACTIVE;
-import static org.briarproject.bramble.api.plugin.Plugin.State.DISABLED;
-import static org.briarproject.bramble.api.plugin.Plugin.State.INACTIVE;
-import static org.briarproject.bramble.util.IoUtils.tryToClose;
 import static org.briarproject.bramble.util.LogUtils.logException;
 import static org.briarproject.bramble.util.PrivacyUtils.scrubSocketAddress;
 import static org.briarproject.bramble.util.StringUtils.isNullOrEmpty;
 
 @MethodsNotNullByDefault
 @ParametersNotNullByDefault
-abstract class TcpPlugin implements DuplexPlugin, EventListener {
+abstract class TcpPlugin implements DuplexPlugin {
 
 	private static final Logger LOG = getLogger(TcpPlugin.class.getName());
 
@@ -68,9 +57,12 @@ abstract class TcpPlugin implements DuplexPlugin, EventListener {
 	protected final Executor ioExecutor, bindExecutor;
 	protected final Backoff backoff;
 	protected final PluginCallback callback;
-	protected final int maxLatency, maxIdleTime, socketTimeout;
+	protected final int maxLatency, maxIdleTime;
+	protected final int connectionTimeout, socketTimeout;
 	protected final AtomicBoolean used = new AtomicBoolean(false);
-	protected final PluginState state = new PluginState();
+
+	protected volatile boolean running = false;
+	protected volatile ServerSocket socket = null;
 
 	/**
 	 * Returns zero or more socket addresses on which the plugin should listen,
@@ -95,15 +87,17 @@ abstract class TcpPlugin implements DuplexPlugin, EventListener {
 	 * Returns true if connections to the given address can be attempted.
 	 */
 	@SuppressWarnings("BooleanMethodIsAlwaysInverted")
-	protected abstract boolean isConnectable(InetSocketAddress remote);
+	protected abstract boolean isConnectable(InterfaceAddress local,
+			InetSocketAddress remote);
 
 	TcpPlugin(Executor ioExecutor, Backoff backoff, PluginCallback callback,
-			int maxLatency, int maxIdleTime) {
+			int maxLatency, int maxIdleTime, int connectionTimeout) {
 		this.ioExecutor = ioExecutor;
 		this.backoff = backoff;
 		this.callback = callback;
 		this.maxLatency = maxLatency;
 		this.maxIdleTime = maxIdleTime;
+		this.connectionTimeout = connectionTimeout;
 		if (maxIdleTime > Integer.MAX_VALUE / 2)
 			socketTimeout = Integer.MAX_VALUE;
 		else socketTimeout = maxIdleTime * 2;
@@ -124,14 +118,14 @@ abstract class TcpPlugin implements DuplexPlugin, EventListener {
 	@Override
 	public void start() {
 		if (used.getAndSet(true)) throw new IllegalStateException();
-		Settings settings = callback.getSettings();
-		state.setStarted(settings.getBoolean(PREF_PLUGIN_ENABLE, false));
+		running = true;
 		bind();
 	}
 
 	protected void bind() {
 		bindExecutor.execute(() -> {
-			if (getState() != INACTIVE) return;
+			if (!running) return;
+			if (socket != null && !socket.isClosed()) return;
 			ServerSocket ss = null;
 			for (InetSocketAddress addr : getLocalSocketAddresses()) {
 				try {
@@ -141,28 +135,34 @@ abstract class TcpPlugin implements DuplexPlugin, EventListener {
 				} catch (IOException e) {
 					if (LOG.isLoggable(INFO))
 						LOG.info("Failed to bind " + scrubSocketAddress(addr));
-					tryToClose(ss, LOG, WARNING);
+					tryToClose(ss);
 				}
 			}
-			if (ss == null) {
+			if (ss == null || !ss.isBound()) {
 				LOG.info("Could not bind server socket");
 				return;
 			}
-			if (!state.setServerSocket(ss)) {
-				LOG.info("Closing redundant server socket");
-				tryToClose(ss, LOG, WARNING);
+			if (!running) {
+				tryToClose(ss);
 				return;
 			}
+			socket = ss;
 			backoff.reset();
 			InetSocketAddress local =
 					(InetSocketAddress) ss.getLocalSocketAddress();
 			setLocalSocketAddress(local);
 			if (LOG.isLoggable(INFO))
 				LOG.info("Listening on " + scrubSocketAddress(local));
-			acceptContactConnections(ss);
+			callback.transportEnabled();
+			acceptContactConnections();
 		});
 	}
 
+	protected void tryToClose(@Nullable ServerSocket ss) {
+		IoUtils.tryToClose(ss, LOG, WARNING);
+		callback.transportDisabled();
+	}
+
 	String getIpPortString(InetSocketAddress a) {
 		String addr = a.getAddress().getHostAddress();
 		int percent = addr.indexOf('%');
@@ -170,16 +170,15 @@ abstract class TcpPlugin implements DuplexPlugin, EventListener {
 		return addr + ":" + a.getPort();
 	}
 
-	private void acceptContactConnections(ServerSocket ss) {
-		while (true) {
+	private void acceptContactConnections() {
+		while (isRunning()) {
 			Socket s;
 			try {
-				s = ss.accept();
+				s = socket.accept();
 				s.setSoTimeout(socketTimeout);
 			} catch (IOException e) {
-				// This is expected when the server socket is closed
-				LOG.info("Server socket closed");
-				state.clearServerSocket(ss);
+				// This is expected when the socket is closed
+				if (LOG.isLoggable(INFO)) LOG.info(e.toString());
 				return;
 			}
 			if (LOG.isLoggable(INFO))
@@ -192,18 +191,13 @@ abstract class TcpPlugin implements DuplexPlugin, EventListener {
 
 	@Override
 	public void stop() {
-		ServerSocket ss = state.setStopped();
-		tryToClose(ss, LOG, WARNING);
+		running = false;
+		tryToClose(socket);
 	}
 
 	@Override
-	public State getState() {
-		return state.getState();
-	}
-
-	@Override
-	public int getReasonDisabled() {
-		return state.getReasonDisabled();
+	public boolean isRunning() {
+		return running && socket != null && !socket.isClosed();
 	}
 
 	@Override
@@ -219,7 +213,7 @@ abstract class TcpPlugin implements DuplexPlugin, EventListener {
 	@Override
 	public void poll(Collection<Pair<TransportProperties, ConnectionHandler>>
 			properties) {
-		if (getState() != ACTIVE) return;
+		if (!isRunning()) return;
 		backoff.increment();
 		for (Pair<TransportProperties, ConnectionHandler> p : properties) {
 			connect(p.getFirst(), p.getSecond());
@@ -238,10 +232,20 @@ abstract class TcpPlugin implements DuplexPlugin, EventListener {
 
 	@Override
 	public DuplexTransportConnection createConnection(TransportProperties p) {
-		ServerSocket ss = state.getServerSocket();
-		if (ss == null) return null;
+		if (!isRunning()) return null;
+		ServerSocket ss = socket;
+		InterfaceAddress local = getLocalInterfaceAddress(ss.getInetAddress());
+		if (local == null) {
+			LOG.warning("No interface for server socket");
+			return null;
+		}
 		for (InetSocketAddress remote : getRemoteSocketAddresses(p)) {
-			if (!isConnectable(remote)) {
+			// Don't try to connect to our own address
+			if (!canConnectToOwnAddress() &&
+					remote.getAddress().equals(ss.getInetAddress())) {
+				continue;
+			}
+			if (!isConnectable(local, remote)) {
 				if (LOG.isLoggable(INFO)) {
 					LOG.info(scrubSocketAddress(remote) +
 							" is not connectable from " +
@@ -254,7 +258,7 @@ abstract class TcpPlugin implements DuplexPlugin, EventListener {
 					LOG.info("Connecting to " + scrubSocketAddress(remote));
 				Socket s = createSocket();
 				s.bind(new InetSocketAddress(ss.getInetAddress(), 0));
-				s.connect(remote);
+				s.connect(remote, connectionTimeout);
 				s.setSoTimeout(socketTimeout);
 				if (LOG.isLoggable(INFO))
 					LOG.info("Connected to " + scrubSocketAddress(remote));
@@ -268,6 +272,19 @@ abstract class TcpPlugin implements DuplexPlugin, EventListener {
 		return null;
 	}
 
+	@Nullable
+	InterfaceAddress getLocalInterfaceAddress(InetAddress a) {
+		for (InterfaceAddress ifAddr : getLocalInterfaceAddresses()) {
+			if (ifAddr.getAddress().equals(a)) return ifAddr;
+		}
+		return null;
+	}
+
+	// Override for testing
+	protected boolean canConnectToOwnAddress() {
+		return false;
+	}
+
 	protected Socket createSocket() throws IOException {
 		return new Socket();
 	}
@@ -323,106 +340,30 @@ abstract class TcpPlugin implements DuplexPlugin, EventListener {
 		throw new UnsupportedOperationException();
 	}
 
-	Collection<InetAddress> getLocalIpAddresses() {
+	List<InterfaceAddress> getLocalInterfaceAddresses() {
+		List<InterfaceAddress> addrs = new ArrayList<>();
+		for (NetworkInterface iface : getNetworkInterfaces()) {
+			addrs.addAll(iface.getInterfaceAddresses());
+		}
+		return addrs;
+	}
+
+	List<InetAddress> getLocalInetAddresses() {
+		List<InetAddress> addrs = new ArrayList<>();
+		for (NetworkInterface iface : getNetworkInterfaces()) {
+			addrs.addAll(list(iface.getInetAddresses()));
+		}
+		return addrs;
+	}
+
+	private List<NetworkInterface> getNetworkInterfaces() {
 		try {
-			Enumeration<NetworkInterface> ifaces = getNetworkInterfaces();
-			if (ifaces == null) return emptyList();
-			List<InetAddress> addrs = new ArrayList<>();
-			for (NetworkInterface iface : list(ifaces))
-				addrs.addAll(list(iface.getInetAddresses()));
-			return addrs;
+			Enumeration<NetworkInterface> ifaces =
+					NetworkInterface.getNetworkInterfaces();
+			return ifaces == null ? emptyList() : list(ifaces);
 		} catch (SocketException e) {
 			logException(LOG, WARNING, e);
 			return emptyList();
 		}
 	}
-
-	@Override
-	public void eventOccurred(Event e) {
-		if (e instanceof SettingsUpdatedEvent) {
-			SettingsUpdatedEvent s = (SettingsUpdatedEvent) e;
-			if (s.getNamespace().equals(getId().getString()))
-				ioExecutor.execute(() -> onSettingsUpdated(s.getSettings()));
-		}
-	}
-
-	@IoExecutor
-	private void onSettingsUpdated(Settings settings) {
-		boolean enabledByUser = settings.getBoolean(PREF_PLUGIN_ENABLE, false);
-		ServerSocket ss = state.setEnabledByUser(enabledByUser);
-		State s = getState();
-		if (ss != null) {
-			LOG.info("Disabled by user, closing server socket");
-			tryToClose(ss, LOG, WARNING);
-		} else if (s == INACTIVE) {
-			LOG.info("Enabled by user, opening server socket");
-			bind();
-		}
-	}
-
-	@ThreadSafe
-	@NotNullByDefault
-	protected class PluginState {
-
-		@GuardedBy("this")
-		private boolean started = false, stopped = false, enabledByUser = false;
-
-		@GuardedBy("this")
-		@Nullable
-		private ServerSocket serverSocket = null;
-
-		synchronized void setStarted(boolean enabledByUser) {
-			started = true;
-			this.enabledByUser = enabledByUser;
-			callback.pluginStateChanged(getState());
-		}
-
-		@Nullable
-		synchronized ServerSocket setStopped() {
-			stopped = true;
-			ServerSocket ss = serverSocket;
-			serverSocket = null;
-			callback.pluginStateChanged(getState());
-			return ss;
-		}
-
-		@Nullable
-		synchronized ServerSocket setEnabledByUser(boolean enabledByUser) {
-			this.enabledByUser = enabledByUser;
-			ServerSocket ss = null;
-			if (!enabledByUser) {
-				ss = serverSocket;
-				serverSocket = null;
-			}
-			callback.pluginStateChanged(getState());
-			return ss;
-		}
-
-		@Nullable
-		synchronized ServerSocket getServerSocket() {
-			return serverSocket;
-		}
-
-		synchronized boolean setServerSocket(ServerSocket ss) {
-			if (stopped || serverSocket != null) return false;
-			serverSocket = ss;
-			callback.pluginStateChanged(getState());
-			return true;
-		}
-
-		synchronized void clearServerSocket(ServerSocket ss) {
-			if (serverSocket == ss) serverSocket = null;
-			callback.pluginStateChanged(getState());
-		}
-
-		synchronized State getState() {
-			if (!started || stopped || !enabledByUser) return DISABLED;
-			return serverSocket == null ? INACTIVE : ACTIVE;
-		}
-
-		synchronized int getReasonDisabled() {
-			if (!started || stopped) return REASON_STARTING_STOPPING;
-			return enabledByUser ? -1 : REASON_USER;
-		}
-	}
 }

bramble-core/src/main/java/org/briarproject/bramble/plugin/tcp/WanTcpPlugin.java

@@ -10,6 +10,7 @@ import org.briarproject.bramble.api.properties.TransportProperties;
 import java.net.Inet4Address;
 import java.net.InetAddress;
 import java.net.InetSocketAddress;
+import java.net.InterfaceAddress;
 import java.util.LinkedList;
 import java.util.List;
 import java.util.concurrent.Executor;
@@ -29,8 +30,10 @@ class WanTcpPlugin extends TcpPlugin {
 	private volatile MappingResult mappingResult;
 
 	WanTcpPlugin(Executor ioExecutor, Backoff backoff, PortMapper portMapper,
-			PluginCallback callback, int maxLatency, int maxIdleTime) {
-		super(ioExecutor, backoff, callback, maxLatency, maxIdleTime);
+			PluginCallback callback, int maxLatency, int maxIdleTime,
+			int connectionTimeout) {
+		super(ioExecutor, backoff, callback, maxLatency, maxIdleTime,
+				connectionTimeout);
 		this.portMapper = portMapper;
 	}
 
@@ -45,7 +48,7 @@ class WanTcpPlugin extends TcpPlugin {
 		TransportProperties p = callback.getLocalProperties();
 		InetSocketAddress old = parseSocketAddress(p.get(PROP_IP_PORT));
 		List<InetSocketAddress> addrs = new LinkedList<>();
-		for (InetAddress a : getLocalIpAddresses()) {
+		for (InetAddress a : getLocalInetAddresses()) {
 			if (isAcceptableAddress(a)) {
 				// If this is the old address, try to use the same port
 				if (old != null && old.getAddress().equals(a))
@@ -86,7 +89,8 @@ class WanTcpPlugin extends TcpPlugin {
 	}
 
 	@Override
-	protected boolean isConnectable(InetSocketAddress remote) {
+	protected boolean isConnectable(InterfaceAddress local,
+			InetSocketAddress remote) {
 		if (remote.getPort() == 0) return false;
 		return isAcceptableAddress(remote.getAddress());
 	}

bramble-core/src/main/java/org/briarproject/bramble/plugin/tcp/WanTcpPluginFactory.java

@@ -1,6 +1,5 @@
 package org.briarproject.bramble.plugin.tcp;
 
-import org.briarproject.bramble.api.event.EventBus;
 import org.briarproject.bramble.api.lifecycle.ShutdownManager;
 import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
 import org.briarproject.bramble.api.plugin.Backoff;
@@ -20,21 +19,20 @@ import static org.briarproject.bramble.api.plugin.WanTcpConstants.ID;
 @NotNullByDefault
 public class WanTcpPluginFactory implements DuplexPluginFactory {
 
-	private static final int MAX_LATENCY = 30 * 1000; // 30 seconds
-	private static final int MAX_IDLE_TIME = 30 * 1000; // 30 seconds
-	private static final int MIN_POLLING_INTERVAL = 60 * 1000; // 1 minute
-	private static final int MAX_POLLING_INTERVAL = 10 * 60 * 1000; // 10 mins
+	private static final int MAX_LATENCY = 30_000; // 30 seconds
+	private static final int MAX_IDLE_TIME = 30_000; // 30 seconds
+	private static final int CONNECTION_TIMEOUT = 30_000; // 30 seconds
+	private static final int MIN_POLLING_INTERVAL = 60_000; // 1 minute
+	private static final int MAX_POLLING_INTERVAL = 600_000; // 10 mins
 	private static final double BACKOFF_BASE = 1.2;
 
 	private final Executor ioExecutor;
-	private final EventBus eventBus;
 	private final BackoffFactory backoffFactory;
 	private final ShutdownManager shutdownManager;
 
-	public WanTcpPluginFactory(Executor ioExecutor, EventBus eventBus,
+	public WanTcpPluginFactory(Executor ioExecutor,
 			BackoffFactory backoffFactory, ShutdownManager shutdownManager) {
 		this.ioExecutor = ioExecutor;
-		this.eventBus = eventBus;
 		this.backoffFactory = backoffFactory;
 		this.shutdownManager = shutdownManager;
 	}
@@ -53,10 +51,8 @@ public class WanTcpPluginFactory implements DuplexPluginFactory {
 	public DuplexPlugin createPlugin(PluginCallback callback) {
 		Backoff backoff = backoffFactory.createBackoff(MIN_POLLING_INTERVAL,
 				MAX_POLLING_INTERVAL, BACKOFF_BASE);
-		WanTcpPlugin plugin = new WanTcpPlugin(ioExecutor, backoff,
+		return new WanTcpPlugin(ioExecutor, backoff,
 				new PortMapperImpl(shutdownManager), callback, MAX_LATENCY,
-				MAX_IDLE_TIME);
-		eventBus.addListener(plugin);
-		return plugin;
+				MAX_IDLE_TIME, CONNECTION_TIMEOUT);
 	}
 }

bramble-core/src/main/java/org/briarproject/bramble/plugin/tor/TorPlugin.java

@@ -15,7 +15,6 @@ import org.briarproject.bramble.api.network.NetworkManager;
 import org.briarproject.bramble.api.network.NetworkStatus;
 import org.briarproject.bramble.api.network.event.NetworkStatusEvent;
 import org.briarproject.bramble.api.nullsafety.MethodsNotNullByDefault;
-import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
 import org.briarproject.bramble.api.nullsafety.ParametersNotNullByDefault;
 import org.briarproject.bramble.api.plugin.Backoff;
 import org.briarproject.bramble.api.plugin.ConnectionHandler;
@@ -55,9 +54,6 @@ import java.util.logging.Logger;
 import java.util.regex.Pattern;
 import java.util.zip.ZipInputStream;
 
-import javax.annotation.Nullable;
-import javax.annotation.concurrent.GuardedBy;
-import javax.annotation.concurrent.ThreadSafe;
 import javax.net.SocketFactory;
 
 import static java.util.Arrays.asList;
@@ -69,10 +65,6 @@ import static java.util.logging.Logger.getLogger;
 import static net.freehaven.tor.control.TorControlCommands.HS_ADDRESS;
 import static net.freehaven.tor.control.TorControlCommands.HS_PRIVKEY;
 import static org.briarproject.bramble.api.nullsafety.NullSafety.requireNonNull;
-import static org.briarproject.bramble.api.plugin.Plugin.State.ACTIVE;
-import static org.briarproject.bramble.api.plugin.Plugin.State.DISABLED;
-import static org.briarproject.bramble.api.plugin.Plugin.State.ENABLING;
-import static org.briarproject.bramble.api.plugin.Plugin.State.INACTIVE;
 import static org.briarproject.bramble.api.plugin.TorConstants.CONTROL_PORT;
 import static org.briarproject.bramble.api.plugin.TorConstants.ID;
 import static org.briarproject.bramble.api.plugin.TorConstants.PREF_TOR_MOBILE;
@@ -84,9 +76,6 @@ import static org.briarproject.bramble.api.plugin.TorConstants.PREF_TOR_ONLY_WHE
 import static org.briarproject.bramble.api.plugin.TorConstants.PREF_TOR_PORT;
 import static org.briarproject.bramble.api.plugin.TorConstants.PROP_ONION_V2;
 import static org.briarproject.bramble.api.plugin.TorConstants.PROP_ONION_V3;
-import static org.briarproject.bramble.api.plugin.TorConstants.REASON_BATTERY;
-import static org.briarproject.bramble.api.plugin.TorConstants.REASON_COUNTRY_BLOCKED;
-import static org.briarproject.bramble.api.plugin.TorConstants.REASON_MOBILE_DATA;
 import static org.briarproject.bramble.plugin.tor.TorRendezvousCrypto.SEED_BYTES;
 import static org.briarproject.bramble.util.IoUtils.copyAndClose;
 import static org.briarproject.bramble.util.IoUtils.tryToClose;
@@ -124,14 +113,16 @@ abstract class TorPlugin implements DuplexPlugin, EventHandler, EventListener {
 	private final int maxLatency, maxIdleTime, socketTimeout;
 	private final File torDirectory, torFile, geoIpFile, obfs4File, configFile;
 	private final File doneFile, cookieFile;
+	private final ConnectionStatus connectionStatus;
 	private final AtomicBoolean used = new AtomicBoolean(false);
 
-	protected final PluginState state = new PluginState();
-
+	private volatile ServerSocket socket = null;
 	private volatile Socket controlSocket = null;
 	private volatile TorControlConnection controlConnection = null;
 	private volatile Settings settings = null;
 
+	protected volatile boolean running = false;
+
 	protected abstract int getProcessId();
 
 	protected abstract long getLastUpdateTime();
@@ -168,6 +159,7 @@ abstract class TorPlugin implements DuplexPlugin, EventHandler, EventListener {
 		configFile = new File(torDirectory, "torrc");
 		doneFile = new File(torDirectory, "done");
 		cookieFile = new File(torDirectory, ".tor/control_auth_cookie");
+		connectionStatus = new ConnectionStatus();
 		// Don't execute more than one connection status check at a time
 		connectionStatusExecutor =
 				new PoliteExecutor("TorPlugin", ioExecutor, 1);
@@ -191,7 +183,6 @@ abstract class TorPlugin implements DuplexPlugin, EventHandler, EventListener {
 	@Override
 	public void start() throws PluginException {
 		if (used.getAndSet(true)) throw new IllegalStateException();
-		state.setStarted();
 		if (!torDirectory.exists()) {
 			if (!torDirectory.mkdirs()) {
 				LOG.warning("Could not create Tor directory.");
@@ -199,7 +190,7 @@ abstract class TorPlugin implements DuplexPlugin, EventHandler, EventListener {
 			}
 		}
 		// Load the settings
-		settings = migrateSettings(callback.getSettings());
+		settings = callback.getSettings();
 		// Install or update the assets if necessary
 		if (!assetsAreUpToDate()) installAssets();
 		if (cookieFile.exists() && !cookieFile.delete())
@@ -267,6 +258,7 @@ abstract class TorPlugin implements DuplexPlugin, EventHandler, EventListener {
 			// Tell Tor to exit when the control connection is closed
 			controlConnection.takeOwnership();
 			controlConnection.resetConf(singletonList(OWNER));
+			running = true;
 			// Register to receive events from the Tor process
 			controlConnection.setEventHandler(this);
 			controlConnection.setEvents(asList(EVENTS));
@@ -274,12 +266,11 @@ abstract class TorPlugin implements DuplexPlugin, EventHandler, EventListener {
 			String phase = controlConnection.getInfo("status/bootstrap-phase");
 			if (phase != null && phase.contains("PROGRESS=100")) {
 				LOG.info("Tor has already bootstrapped");
-				state.setBootstrapped();
+				connectionStatus.setBootstrapped();
 			}
 		} catch (IOException e) {
 			throw new PluginException(e);
 		}
-		state.setTorStarted();
 		// Check whether we're online
 		updateConnectionStatus(networkManager.getNetworkStatus(),
 				batteryManager.isCharging());
@@ -287,18 +278,6 @@ abstract class TorPlugin implements DuplexPlugin, EventHandler, EventListener {
 		bind();
 	}
 
-	// TODO: Remove after a reasonable migration period (added 2020-01-16)
-	private Settings migrateSettings(Settings settings) {
-		int network = settings.getInt(PREF_TOR_NETWORK,
-				PREF_TOR_NETWORK_AUTOMATIC);
-		if (network == PREF_TOR_NETWORK_NEVER) {
-			settings.putInt(PREF_TOR_NETWORK, PREF_TOR_NETWORK_AUTOMATIC);
-			settings.putBoolean(PREF_PLUGIN_ENABLE, false);
-			callback.mergeSettings(settings);
-		}
-		return settings;
-	}
-
 	private boolean assetsAreUpToDate() {
 		return doneFile.lastModified() > getLastUpdateTime();
 	}
@@ -414,11 +393,11 @@ abstract class TorPlugin implements DuplexPlugin, EventHandler, EventListener {
 				tryToClose(ss, LOG, WARNING);
 				return;
 			}
-			if (!state.setServerSocket(ss)) {
-				LOG.info("Closing redundant server socket");
+			if (!running) {
 				tryToClose(ss, LOG, WARNING);
 				return;
 			}
+			socket = ss;
 			// Store the port number
 			String localPort = String.valueOf(ss.getLocalPort());
 			Settings s = new Settings();
@@ -433,7 +412,7 @@ abstract class TorPlugin implements DuplexPlugin, EventHandler, EventListener {
 	}
 
 	private void publishHiddenService(String port) {
-		if (!state.isTorRunning()) return;
+		if (!running) return;
 		LOG.info("Creating hidden service");
 		String privKey = settings.get(HS_PRIVKEY);
 		Map<Integer, String> portLines = singletonMap(80, "127.0.0.1:" + port);
@@ -471,15 +450,14 @@ abstract class TorPlugin implements DuplexPlugin, EventHandler, EventListener {
 	}
 
 	private void acceptContactConnections(ServerSocket ss) {
-		while (true) {
+		while (running) {
 			Socket s;
 			try {
 				s = ss.accept();
 				s.setSoTimeout(socketTimeout);
 			} catch (IOException e) {
-				// This is expected when the server socket is closed
-				LOG.info("Server socket closed");
-				state.clearServerSocket(ss);
+				// This is expected when the socket is closed
+				if (LOG.isLoggable(INFO)) LOG.info(e.toString());
 				return;
 			}
 			LOG.info("Connection received");
@@ -489,8 +467,10 @@ abstract class TorPlugin implements DuplexPlugin, EventHandler, EventListener {
 	}
 
 	protected void enableNetwork(boolean enable) throws IOException {
-		state.enableNetwork(enable);
+		if (!running) return;
+		connectionStatus.enableNetwork(enable);
 		controlConnection.setConf("DisableNetwork", enable ? "0" : "1");
+		if (!enable) callback.transportDisabled();
 	}
 
 	private void enableBridges(boolean enable, boolean needsMeek)
@@ -514,8 +494,9 @@ abstract class TorPlugin implements DuplexPlugin, EventHandler, EventListener {
 
 	@Override
 	public void stop() {
-		ServerSocket ss = state.setStopped();
-		tryToClose(ss, LOG, WARNING);
+		running = false;
+		tryToClose(socket, LOG, WARNING);
+		callback.transportDisabled();
 		if (controlSocket != null && controlConnection != null) {
 			try {
 				LOG.info("Stopping Tor");
@@ -529,13 +510,8 @@ abstract class TorPlugin implements DuplexPlugin, EventHandler, EventListener {
 	}
 
 	@Override
-	public State getState() {
-		return state.getState();
-	}
-
-	@Override
-	public int getReasonDisabled() {
-		return state.getReasonDisabled();
+	public boolean isRunning() {
+		return running && connectionStatus.isConnected();
 	}
 
 	@Override
@@ -551,7 +527,7 @@ abstract class TorPlugin implements DuplexPlugin, EventHandler, EventListener {
 	@Override
 	public void poll(Collection<Pair<TransportProperties, ConnectionHandler>>
 			properties) {
-		if (getState() != ACTIVE) return;
+		if (!isRunning()) return;
 		backoff.increment();
 		for (Pair<TransportProperties, ConnectionHandler> p : properties) {
 			connect(p.getFirst(), p.getSecond());
@@ -570,7 +546,7 @@ abstract class TorPlugin implements DuplexPlugin, EventHandler, EventListener {
 
 	@Override
 	public DuplexTransportConnection createConnection(TransportProperties p) {
-		if (getState() != ACTIVE) return null;
+		if (!isRunning()) return null;
 		String bestOnion = null;
 		String onion2 = p.get(PROP_ONION_V2);
 		String onion3 = p.get(PROP_ONION_V3);
@@ -658,8 +634,8 @@ abstract class TorPlugin implements DuplexPlugin, EventHandler, EventListener {
 								new TorTransportConnection(this, s));
 					}
 				} catch (IOException e) {
-					// This is expected when the server socket is closed
-					LOG.info("Rendezvous server socket closed");
+					// This is expected when the socket is closed
+					if (LOG.isLoggable(INFO)) LOG.info(e.toString());
 				}
 			});
 			Map<Integer, String> portLines =
@@ -687,9 +663,10 @@ abstract class TorPlugin implements DuplexPlugin, EventHandler, EventListener {
 	@Override
 	public void circuitStatus(String status, String id, String path) {
 		if (status.equals("BUILT") &&
-				state.getAndSetCircuitBuilt()) {
+				connectionStatus.getAndSetCircuitBuilt()) {
 			LOG.info("First circuit built");
 			backoff.reset();
+			if (isRunning()) callback.transportEnabled();
 		}
 	}
 
@@ -720,8 +697,9 @@ abstract class TorPlugin implements DuplexPlugin, EventHandler, EventListener {
 	public void message(String severity, String msg) {
 		if (LOG.isLoggable(INFO)) LOG.info(severity + " " + msg);
 		if (severity.equals("NOTICE") && msg.startsWith("Bootstrapped 100%")) {
-			state.setBootstrapped();
+			connectionStatus.setBootstrapped();
 			backoff.reset();
+			if (isRunning()) callback.transportEnabled();
 		}
 	}
 
@@ -758,7 +736,7 @@ abstract class TorPlugin implements DuplexPlugin, EventHandler, EventListener {
 	private void disableNetwork() {
 		connectionStatusExecutor.execute(() -> {
 			try {
-				if (state.isTorRunning()) enableNetwork(false);
+				enableNetwork(false);
 			} catch (IOException ex) {
 				logException(LOG, WARNING, ex);
 			}
@@ -768,13 +746,12 @@ abstract class TorPlugin implements DuplexPlugin, EventHandler, EventListener {
 	private void updateConnectionStatus(NetworkStatus status,
 			boolean charging) {
 		connectionStatusExecutor.execute(() -> {
-			if (!state.isTorRunning()) return;
+			if (!running) return;
 			boolean online = status.isConnected();
 			boolean wifi = status.isWifi();
 			String country = locationUtils.getCurrentCountry();
 			boolean blocked =
 					circumventionProvider.isTorProbablyBlocked(country);
-			boolean enabledByUser = settings.getBoolean(PREF_PLUGIN_ENABLE, true);
 			int network = settings.getInt(PREF_TOR_NETWORK,
 					PREF_TOR_NETWORK_AUTOMATIC);
 			boolean useMobile = settings.getBoolean(PREF_TOR_MOBILE, true);
@@ -785,67 +762,47 @@ abstract class TorPlugin implements DuplexPlugin, EventHandler, EventListener {
 
 			if (LOG.isLoggable(INFO)) {
 				LOG.info("Online: " + online + ", wifi: " + wifi);
-				if (country.isEmpty()) LOG.info("Country code unknown");
+				if ("".equals(country)) LOG.info("Country code unknown");
 				else LOG.info("Country code: " + country);
 				LOG.info("Charging: " + charging);
 			}
 
-			boolean enableNetwork = false, enableBridges = false;
-			boolean useMeek = false, enableConnectionPadding = false;
-			boolean disabledBySettings = false;
-			int reasonDisabled = REASON_STARTING_STOPPING;
-
-			if (!online) {
-				LOG.info("Disabling network, device is offline");
-			} else if (!enabledByUser) {
-				LOG.info("Disabling network, user has disabled Tor");
-				disabledBySettings = true;
-				reasonDisabled = REASON_USER;
-			} else if (!charging && onlyWhenCharging) {
-				LOG.info("Disabling network, device is on battery");
-				disabledBySettings = true;
-				reasonDisabled = REASON_BATTERY;
-			} else if (!useMobile && !wifi) {
-				LOG.info("Disabling network, device is using mobile data");
-				disabledBySettings = true;
-				reasonDisabled = REASON_MOBILE_DATA;
-			} else if (automatic && blocked && !bridgesWork) {
-				LOG.info("Disabling network, country is blocked");
-				disabledBySettings = true;
-				reasonDisabled = REASON_COUNTRY_BLOCKED;
-			} else {
-				LOG.info("Enabling network");
-				enableNetwork = true;
-				if (network == PREF_TOR_NETWORK_WITH_BRIDGES ||
+			try {
+				if (!online) {
+					LOG.info("Disabling network, device is offline");
+					enableNetwork(false);
+				} else if (!charging && onlyWhenCharging) {
+					LOG.info("Disabling network, device is on battery");
+					enableNetwork(false);
+				} else if (network == PREF_TOR_NETWORK_NEVER ||
+						(!useMobile && !wifi)) {
+					LOG.info("Disabling network, device is using mobile data");
+					enableNetwork(false);
+				} else if (automatic && blocked && !bridgesWork) {
+					LOG.info("Disabling network, country is blocked");
+					enableNetwork(false);
+				} else if (network == PREF_TOR_NETWORK_WITH_BRIDGES ||
 						(automatic && bridgesWork)) {
 					if (circumventionProvider.needsMeek(country)) {
-						LOG.info("Using meek bridges");
-						enableBridges = true;
-						useMeek = true;
+						LOG.info("Enabling network, using meek bridges");
+						enableBridges(true, true);
 					} else {
-						LOG.info("Using obfs4 bridges");
-						enableBridges = true;
+						LOG.info("Enabling network, using obfs4 bridges");
+						enableBridges(true, false);
 					}
+					enableNetwork(true);
 				} else {
-					LOG.info("Not using bridges");
+					LOG.info("Enabling network, not using bridges");
+					enableBridges(false, false);
+					enableNetwork(true);
 				}
-				if (wifi && charging) {
+				if (online && wifi && charging) {
 					LOG.info("Enabling connection padding");
-					enableConnectionPadding = true;
+					enableConnectionPadding(true);
 				} else {
 					LOG.info("Disabling connection padding");
+					enableConnectionPadding(false);
 				}
-			}
-
-
-			state.setDisabledBySettings(disabledBySettings, reasonDisabled);
-
-			try {
-				if (enableNetwork) {
-					enableBridges(enableBridges, useMeek);
-					enableConnectionPadding(enableConnectionPadding);
-				}
-				enableNetwork(enableNetwork);
 			} catch (IOException e) {
 				logException(LOG, WARNING, e);
 			}
@@ -853,100 +810,33 @@ abstract class TorPlugin implements DuplexPlugin, EventHandler, EventListener {
 	}
 
 	private void enableConnectionPadding(boolean enable) throws IOException {
+		if (!running) return;
 		controlConnection.setConf("ConnectionPadding", enable ? "1" : "0");
 	}
 
-	@ThreadSafe
-	@NotNullByDefault
-	protected class PluginState {
+	private static class ConnectionStatus {
 
-		@GuardedBy("this")
-		private boolean started = false,
-				stopped = false,
-				torStarted = false,
-				networkInitialised = false,
-				networkEnabled = false,
-				bootstrapped = false,
-				circuitBuilt = false,
-				disabledBySettings = false;
+		// All of the following are locking: this
+		private boolean networkEnabled = false;
+		private boolean bootstrapped = false, circuitBuilt = false;
 
-		@GuardedBy("this")
-		private int reasonDisabled = REASON_STARTING_STOPPING;
-
-		@GuardedBy("this")
-		@Nullable
-		private ServerSocket serverSocket = null;
-
-		synchronized void setStarted() {
-			started = true;
-			callback.pluginStateChanged(getState());
-		}
-
-		// Doesn't affect getState()
-		synchronized void setTorStarted() {
-			torStarted = true;
-		}
-
-		synchronized boolean isTorRunning() {
-			return torStarted && !stopped;
-		}
-
-		@Nullable
-		synchronized ServerSocket setStopped() {
-			stopped = true;
-			ServerSocket ss = serverSocket;
-			serverSocket = null;
-			callback.pluginStateChanged(getState());
-			return ss;
-		}
-
-		synchronized void setBootstrapped() {
+		private synchronized void setBootstrapped() {
 			bootstrapped = true;
-			callback.pluginStateChanged(getState());
 		}
 
-		synchronized boolean getAndSetCircuitBuilt() {
+		private synchronized boolean getAndSetCircuitBuilt() {
 			boolean firstCircuit = !circuitBuilt;
 			circuitBuilt = true;
-			callback.pluginStateChanged(getState());
 			return firstCircuit;
 		}
 
-		synchronized void enableNetwork(boolean enable) {
-			networkInitialised = true;
+		private synchronized void enableNetwork(boolean enable) {
 			networkEnabled = enable;
 			if (!enable) circuitBuilt = false;
-			callback.pluginStateChanged(getState());
 		}
 
-		synchronized void setDisabledBySettings(boolean disabledBySettings,
-				int reasonDisabled) {
-			this.disabledBySettings = disabledBySettings;
-			this.reasonDisabled = reasonDisabled;
-			callback.pluginStateChanged(getState());
-		}
-
-		// Doesn't affect getState()
-		synchronized boolean setServerSocket(ServerSocket ss) {
-			if (stopped || serverSocket != null) return false;
-			serverSocket = ss;
-			return true;
-		}
-
-		// Doesn't affect getState()
-		synchronized void clearServerSocket(ServerSocket ss) {
-			if (serverSocket == ss) serverSocket = null;
-		}
-
-		synchronized State getState() {
-			if (!started || stopped || disabledBySettings) return DISABLED;
-			if (!networkInitialised) return ENABLING;
-			if (!networkEnabled) return INACTIVE;
-			return bootstrapped && circuitBuilt ? ACTIVE : ENABLING;
-		}
-
-		synchronized int getReasonDisabled() {
-			return getState() == DISABLED ? reasonDisabled : -1;
+		private synchronized boolean isConnected() {
+			return networkEnabled && bootstrapped && circuitBuilt;
 		}
 	}
 }

bramble-core/src/main/java/org/briarproject/bramble/properties/TransportPropertyManagerImpl.java

@@ -37,6 +37,11 @@ import javax.annotation.Nullable;
 import javax.annotation.concurrent.Immutable;
 import javax.inject.Inject;
 
+import static org.briarproject.bramble.api.properties.TransportPropertyConstants.GROUP_KEY_DISCOVERED;
+import static org.briarproject.bramble.api.properties.TransportPropertyConstants.MSG_KEY_LOCAL;
+import static org.briarproject.bramble.api.properties.TransportPropertyConstants.MSG_KEY_TRANSPORT_ID;
+import static org.briarproject.bramble.api.properties.TransportPropertyConstants.MSG_KEY_VERSION;
+
 @Immutable
 @NotNullByDefault
 class TransportPropertyManagerImpl implements TransportPropertyManager,
@@ -111,10 +116,10 @@ class TransportPropertyManagerImpl implements TransportPropertyManager,
 		try {
 			// Find the latest update for this transport, if any
 			BdfDictionary d = metadataParser.parse(meta);
-			TransportId t = new TransportId(d.getString("transportId"));
+			TransportId t = new TransportId(d.getString(MSG_KEY_TRANSPORT_ID));
 			LatestUpdate latest = findLatest(txn, m.getGroupId(), t, false);
 			if (latest != null) {
-				if (d.getLong("version") > latest.version) {
+				if (d.getLong(MSG_KEY_VERSION) > latest.version) {
 					// This update is newer - delete the previous update
 					db.deleteMessage(txn, latest.messageId);
 					db.deleteMessageMetadata(txn, latest.messageId);
@@ -140,6 +145,27 @@ class TransportPropertyManagerImpl implements TransportPropertyManager,
 		}
 	}
 
+	@Override
+	public void addRemotePropertiesFromConnection(ContactId c, TransportId t,
+			TransportProperties props) throws DbException {
+		if (props.isEmpty()) return;
+		try {
+			db.transaction(false, txn -> {
+				Group g = getContactGroup(db.getContact(txn, c));
+				BdfDictionary meta = clientHelper.getGroupMetadataAsDictionary(
+						txn, g.getId());
+				BdfDictionary discovered =
+						meta.getOptionalDictionary(GROUP_KEY_DISCOVERED);
+				if (discovered == null) discovered = new BdfDictionary();
+				discovered.putAll(props);
+				meta.put(GROUP_KEY_DISCOVERED, discovered);
+				clientHelper.mergeGroupMetadata(txn, g.getId(), meta);
+			});
+		} catch (FormatException e) {
+			throw new DbException(e);
+		}
+	}
+
 	@Override
 	public Map<TransportId, TransportProperties> getLocalProperties()
 			throws DbException {
@@ -203,12 +229,26 @@ class TransportPropertyManagerImpl implements TransportPropertyManager,
 		Group g = getContactGroup(c);
 		try {
 			// Find the latest remote update
+			TransportProperties remote;
 			LatestUpdate latest = findLatest(txn, g.getId(), t, false);
-			if (latest == null) return new TransportProperties();
-			// Retrieve and parse the latest remote properties
-			BdfList message =
-					clientHelper.getMessageAsList(txn, latest.messageId);
-			return parseProperties(message);
+			if (latest == null) {
+				remote = new TransportProperties();
+			} else {
+				// Retrieve and parse the latest remote properties
+				BdfList message =
+						clientHelper.getMessageAsList(txn, latest.messageId);
+				remote = parseProperties(message);
+			}
+			// Merge in any discovered properties
+			BdfDictionary meta =
+					clientHelper.getGroupMetadataAsDictionary(txn, g.getId());
+			BdfDictionary d = meta.getOptionalDictionary(GROUP_KEY_DISCOVERED);
+			if (d == null) return remote;
+			TransportProperties merged =
+					clientHelper.parseAndValidateTransportProperties(d);
+			// Received properties override discovered properties
+			merged.putAll(remote);
+			return merged;
 		} catch (FormatException e) {
 			throw new DbException(e);
 		}
@@ -281,9 +321,9 @@ class TransportPropertyManagerImpl implements TransportPropertyManager,
 			long now = clock.currentTimeMillis();
 			Message m = clientHelper.createMessage(g, now, body);
 			BdfDictionary meta = new BdfDictionary();
-			meta.put("transportId", t.getString());
-			meta.put("version", version);
-			meta.put("local", local);
+			meta.put(MSG_KEY_TRANSPORT_ID, t.getString());
+			meta.put(MSG_KEY_VERSION, version);
+			meta.put(MSG_KEY_LOCAL, local);
 			clientHelper.addLocalMessage(txn, m, meta, shared, false);
 		} catch (FormatException e) {
 			throw new RuntimeException(e);
@@ -302,8 +342,9 @@ class TransportPropertyManagerImpl implements TransportPropertyManager,
 				.getMessageMetadataAsDictionary(txn, localGroup.getId());
 		for (Entry<MessageId, BdfDictionary> e : metadata.entrySet()) {
 			BdfDictionary meta = e.getValue();
-			TransportId t = new TransportId(meta.getString("transportId"));
-			long version = meta.getLong("version");
+			TransportId t =
+					new TransportId(meta.getString(MSG_KEY_TRANSPORT_ID));
+			long version = meta.getLong(MSG_KEY_VERSION);
 			latestUpdates.put(t, new LatestUpdate(e.getKey(), version));
 		}
 		return latestUpdates;
@@ -316,9 +357,10 @@ class TransportPropertyManagerImpl implements TransportPropertyManager,
 				clientHelper.getMessageMetadataAsDictionary(txn, g);
 		for (Entry<MessageId, BdfDictionary> e : metadata.entrySet()) {
 			BdfDictionary meta = e.getValue();
-			if (meta.getString("transportId").equals(t.getString())
-					&& meta.getBoolean("local") == local) {
-				return new LatestUpdate(e.getKey(), meta.getLong("version"));
+			if (meta.getString(MSG_KEY_TRANSPORT_ID).equals(t.getString())
+					&& meta.getBoolean(MSG_KEY_LOCAL) == local) {
+				return new LatestUpdate(e.getKey(),
+						meta.getLong(MSG_KEY_VERSION));
 			}
 		}
 		return null;

bramble-core/src/main/java/org/briarproject/bramble/rendezvous/RendezvousPollerImpl.java

@@ -31,8 +31,8 @@ import org.briarproject.bramble.api.plugin.TransportConnectionWriter;
 import org.briarproject.bramble.api.plugin.TransportId;
 import org.briarproject.bramble.api.plugin.duplex.DuplexPlugin;
 import org.briarproject.bramble.api.plugin.duplex.DuplexTransportConnection;
-import org.briarproject.bramble.api.plugin.event.TransportActiveEvent;
-import org.briarproject.bramble.api.plugin.event.TransportInactiveEvent;
+import org.briarproject.bramble.api.plugin.event.TransportDisabledEvent;
+import org.briarproject.bramble.api.plugin.event.TransportEnabledEvent;
 import org.briarproject.bramble.api.properties.TransportProperties;
 import org.briarproject.bramble.api.rendezvous.KeyMaterialSource;
 import org.briarproject.bramble.api.rendezvous.RendezvousEndpoint;
@@ -269,11 +269,11 @@ class RendezvousPollerImpl implements RendezvousPoller, Service, EventListener {
 		} else if (e instanceof PendingContactRemovedEvent) {
 			PendingContactRemovedEvent p = (PendingContactRemovedEvent) e;
 			removePendingContactAsync(p.getId());
-		} else if (e instanceof TransportActiveEvent) {
-			TransportActiveEvent t = (TransportActiveEvent) e;
+		} else if (e instanceof TransportEnabledEvent) {
+			TransportEnabledEvent t = (TransportEnabledEvent) e;
 			addTransportAsync(t.getTransportId());
-		} else if (e instanceof TransportInactiveEvent) {
-			TransportInactiveEvent t = (TransportInactiveEvent) e;
+		} else if (e instanceof TransportDisabledEvent) {
+			TransportDisabledEvent t = (TransportDisabledEvent) e;
 			removeTransportAsync(t.getTransportId());
 		} else if (e instanceof RendezvousConnectionOpenedEvent) {
 			RendezvousConnectionOpenedEvent r =

bramble-core/src/main/java/org/briarproject/bramble/reporting/DevReporterImpl.java

@@ -6,7 +6,7 @@ import org.briarproject.bramble.api.event.EventListener;
 import org.briarproject.bramble.api.lifecycle.IoExecutor;
 import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
 import org.briarproject.bramble.api.plugin.TorConstants;
-import org.briarproject.bramble.api.plugin.event.TransportActiveEvent;
+import org.briarproject.bramble.api.plugin.event.TransportEnabledEvent;
 import org.briarproject.bramble.api.reporting.DevConfig;
 import org.briarproject.bramble.api.reporting.DevReporter;
 import org.briarproject.bramble.util.IoUtils;
@@ -92,8 +92,8 @@ class DevReporterImpl implements DevReporter, EventListener {
 
 	@Override
 	public void eventOccurred(Event e) {
-		if (e instanceof TransportActiveEvent) {
-			TransportActiveEvent t = (TransportActiveEvent) e;
+		if (e instanceof TransportEnabledEvent) {
+			TransportEnabledEvent t = (TransportEnabledEvent) e;
 			if (t.getTransportId().equals(TorConstants.ID))
 				ioExecutor.execute(this::sendReports);
 		}

bramble-core/src/main/java/org/briarproject/bramble/sync/DuplexOutgoingSession.java

@@ -11,6 +11,7 @@ import org.briarproject.bramble.api.event.EventListener;
 import org.briarproject.bramble.api.lifecycle.IoExecutor;
 import org.briarproject.bramble.api.lifecycle.event.LifecycleEvent;
 import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
+import org.briarproject.bramble.api.plugin.TransportId;
 import org.briarproject.bramble.api.sync.Ack;
 import org.briarproject.bramble.api.sync.Message;
 import org.briarproject.bramble.api.sync.Offer;
@@ -18,6 +19,7 @@ import org.briarproject.bramble.api.sync.Request;
 import org.briarproject.bramble.api.sync.SyncRecordWriter;
 import org.briarproject.bramble.api.sync.SyncSession;
 import org.briarproject.bramble.api.sync.Versions;
+import org.briarproject.bramble.api.sync.event.CloseSyncConnectionsEvent;
 import org.briarproject.bramble.api.sync.event.GroupVisibilityUpdatedEvent;
 import org.briarproject.bramble.api.sync.event.MessageRequestedEvent;
 import org.briarproject.bramble.api.sync.event.MessageSharedEvent;
@@ -71,6 +73,7 @@ class DuplexOutgoingSession implements SyncSession, EventListener {
 	private final EventBus eventBus;
 	private final Clock clock;
 	private final ContactId contactId;
+	private final TransportId transportId;
 	private final int maxLatency, maxIdleTime;
 	private final StreamWriter streamWriter;
 	private final SyncRecordWriter recordWriter;
@@ -86,14 +89,15 @@ class DuplexOutgoingSession implements SyncSession, EventListener {
 	private volatile boolean interrupted = false;
 
 	DuplexOutgoingSession(DatabaseComponent db, Executor dbExecutor,
-			EventBus eventBus, Clock clock, ContactId contactId, int maxLatency,
-			int maxIdleTime, StreamWriter streamWriter,
-			SyncRecordWriter recordWriter) {
+			EventBus eventBus, Clock clock, ContactId contactId,
+			TransportId transportId, int maxLatency, int maxIdleTime,
+			StreamWriter streamWriter, SyncRecordWriter recordWriter) {
 		this.db = db;
 		this.dbExecutor = dbExecutor;
 		this.eventBus = eventBus;
 		this.clock = clock;
 		this.contactId = contactId;
+		this.transportId = transportId;
 		this.maxLatency = maxLatency;
 		this.maxIdleTime = maxIdleTime;
 		this.streamWriter = streamWriter;
@@ -223,6 +227,9 @@ class DuplexOutgoingSession implements SyncSession, EventListener {
 		} else if (e instanceof LifecycleEvent) {
 			LifecycleEvent l = (LifecycleEvent) e;
 			if (l.getLifecycleState() == STOPPING) interrupt();
+		} else if (e instanceof CloseSyncConnectionsEvent) {
+			CloseSyncConnectionsEvent c = (CloseSyncConnectionsEvent) e;
+			if (c.getTransportId().equals(transportId)) interrupt();
 		}
 	}
 

bramble-core/src/main/java/org/briarproject/bramble/sync/SimplexOutgoingSession.java

@@ -11,11 +11,13 @@ import org.briarproject.bramble.api.event.EventListener;
 import org.briarproject.bramble.api.lifecycle.IoExecutor;
 import org.briarproject.bramble.api.lifecycle.event.LifecycleEvent;
 import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
+import org.briarproject.bramble.api.plugin.TransportId;
 import org.briarproject.bramble.api.sync.Ack;
 import org.briarproject.bramble.api.sync.Message;
 import org.briarproject.bramble.api.sync.SyncRecordWriter;
 import org.briarproject.bramble.api.sync.SyncSession;
 import org.briarproject.bramble.api.sync.Versions;
+import org.briarproject.bramble.api.sync.event.CloseSyncConnectionsEvent;
 import org.briarproject.bramble.api.transport.StreamWriter;
 
 import java.io.IOException;
@@ -56,6 +58,7 @@ class SimplexOutgoingSession implements SyncSession, EventListener {
 	private final Executor dbExecutor;
 	private final EventBus eventBus;
 	private final ContactId contactId;
+	private final TransportId transportId;
 	private final int maxLatency;
 	private final StreamWriter streamWriter;
 	private final SyncRecordWriter recordWriter;
@@ -65,12 +68,14 @@ class SimplexOutgoingSession implements SyncSession, EventListener {
 	private volatile boolean interrupted = false;
 
 	SimplexOutgoingSession(DatabaseComponent db, Executor dbExecutor,
-			EventBus eventBus, ContactId contactId, int maxLatency,
-			StreamWriter streamWriter, SyncRecordWriter recordWriter) {
+			EventBus eventBus, ContactId contactId, TransportId transportId,
+			int maxLatency, StreamWriter streamWriter,
+			SyncRecordWriter recordWriter) {
 		this.db = db;
 		this.dbExecutor = dbExecutor;
 		this.eventBus = eventBus;
 		this.contactId = contactId;
+		this.transportId = transportId;
 		this.maxLatency = maxLatency;
 		this.streamWriter = streamWriter;
 		this.recordWriter = recordWriter;
@@ -123,6 +128,9 @@ class SimplexOutgoingSession implements SyncSession, EventListener {
 		} else if (e instanceof LifecycleEvent) {
 			LifecycleEvent l = (LifecycleEvent) e;
 			if (l.getLifecycleState() == STOPPING) interrupt();
+		} else if (e instanceof CloseSyncConnectionsEvent) {
+			CloseSyncConnectionsEvent c = (CloseSyncConnectionsEvent) e;
+			if (c.getTransportId().equals(transportId)) interrupt();
 		}
 	}
 

bramble-core/src/main/java/org/briarproject/bramble/sync/SyncSessionFactoryImpl.java

@@ -5,6 +5,7 @@ import org.briarproject.bramble.api.db.DatabaseComponent;
 import org.briarproject.bramble.api.db.DatabaseExecutor;
 import org.briarproject.bramble.api.event.EventBus;
 import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
+import org.briarproject.bramble.api.plugin.TransportId;
 import org.briarproject.bramble.api.sync.SyncRecordReader;
 import org.briarproject.bramble.api.sync.SyncRecordReaderFactory;
 import org.briarproject.bramble.api.sync.SyncRecordWriter;
@@ -53,22 +54,23 @@ class SyncSessionFactoryImpl implements SyncSessionFactory {
 	}
 
 	@Override
-	public SyncSession createSimplexOutgoingSession(ContactId c,
+	public SyncSession createSimplexOutgoingSession(ContactId c, TransportId t,
 			int maxLatency, StreamWriter streamWriter) {
 		OutputStream out = streamWriter.getOutputStream();
 		SyncRecordWriter recordWriter =
 				recordWriterFactory.createRecordWriter(out);
-		return new SimplexOutgoingSession(db, dbExecutor, eventBus, c,
+		return new SimplexOutgoingSession(db, dbExecutor, eventBus, c, t,
 				maxLatency, streamWriter, recordWriter);
 	}
 
 	@Override
-	public SyncSession createDuplexOutgoingSession(ContactId c, int maxLatency,
-			int maxIdleTime, StreamWriter streamWriter) {
+	public SyncSession createDuplexOutgoingSession(ContactId c,
+			TransportId t, int maxLatency, int maxIdleTime,
+			StreamWriter streamWriter) {
 		OutputStream out = streamWriter.getOutputStream();
 		SyncRecordWriter recordWriter =
 				recordWriterFactory.createRecordWriter(out);
-		return new DuplexOutgoingSession(db, dbExecutor, eventBus, clock, c,
+		return new DuplexOutgoingSession(db, dbExecutor, eventBus, clock, c, t,
 				maxLatency, maxIdleTime, streamWriter, recordWriter);
 	}
 }

bramble-core/src/test/java/org/briarproject/bramble/account/AccountManagerImplTest.java

@@ -1,6 +1,7 @@
 package org.briarproject.bramble.account;
 
 import org.briarproject.bramble.api.crypto.CryptoComponent;
+import org.briarproject.bramble.api.crypto.DecryptionException;
 import org.briarproject.bramble.api.crypto.KeyStrengthener;
 import org.briarproject.bramble.api.crypto.SecretKey;
 import org.briarproject.bramble.api.db.DatabaseConfig;
@@ -19,12 +20,15 @@ import java.io.FileInputStream;
 import java.io.FileOutputStream;
 import java.io.IOException;
 import java.io.InputStreamReader;
+import java.nio.charset.Charset;
 
 import javax.annotation.Nullable;
 
 import static junit.framework.Assert.assertFalse;
 import static junit.framework.Assert.assertNull;
 import static junit.framework.Assert.assertTrue;
+import static org.briarproject.bramble.api.crypto.DecryptionResult.INVALID_CIPHERTEXT;
+import static org.briarproject.bramble.api.crypto.DecryptionResult.INVALID_PASSWORD;
 import static org.briarproject.bramble.test.TestUtils.deleteTestDirectory;
 import static org.briarproject.bramble.test.TestUtils.getIdentity;
 import static org.briarproject.bramble.test.TestUtils.getRandomBytes;
@@ -35,6 +39,7 @@ import static org.briarproject.bramble.util.StringUtils.toHexString;
 import static org.junit.Assert.assertArrayEquals;
 import static org.junit.Assert.assertEquals;
 import static org.junit.Assert.assertNotNull;
+import static org.junit.Assert.fail;
 
 public class AccountManagerImplTest extends BrambleMockTestCase {
 
@@ -83,8 +88,13 @@ public class AccountManagerImplTest extends BrambleMockTestCase {
 	}
 
 	@Test
-	public void testSignInReturnsFalseIfDbKeyCannotBeLoaded() {
-		assertFalse(accountManager.signIn(password));
+	public void testSignInThrowsExceptionIfDbKeyCannotBeLoaded() {
+		try {
+			accountManager.signIn(password);
+			fail();
+		} catch (DecryptionException expected) {
+			assertEquals(INVALID_CIPHERTEXT, expected.getDecryptionResult());
+		}
 		assertFalse(accountManager.hasDatabaseKey());
 
 		assertFalse(keyFile.exists());
@@ -92,11 +102,11 @@ public class AccountManagerImplTest extends BrambleMockTestCase {
 	}
 
 	@Test
-	public void testSignInReturnsFalseIfPasswordIsWrong() throws Exception {
+	public void testSignInThrowsExceptionIfPasswordIsWrong() throws Exception {
 		context.checking(new Expectations() {{
 			oneOf(crypto).decryptWithPassword(encryptedKey, password,
 					keyStrengthener);
-			will(returnValue(null));
+			will(throwException(new DecryptionException(INVALID_PASSWORD)));
 		}});
 
 		storeDatabaseKey(keyFile, encryptedKeyHex);
@@ -105,7 +115,12 @@ public class AccountManagerImplTest extends BrambleMockTestCase {
 		assertEquals(encryptedKeyHex, loadDatabaseKey(keyFile));
 		assertEquals(encryptedKeyHex, loadDatabaseKey(keyBackupFile));
 
-		assertFalse(accountManager.signIn(password));
+		try {
+			accountManager.signIn(password);
+			fail();
+		} catch (DecryptionException expected) {
+			assertEquals(INVALID_PASSWORD, expected.getDecryptionResult());
+		}
 		assertFalse(accountManager.hasDatabaseKey());
 
 		assertEquals(encryptedKeyHex, loadDatabaseKey(keyFile));
@@ -128,7 +143,7 @@ public class AccountManagerImplTest extends BrambleMockTestCase {
 		assertEquals(encryptedKeyHex, loadDatabaseKey(keyFile));
 		assertEquals(encryptedKeyHex, loadDatabaseKey(keyBackupFile));
 
-		assertTrue(accountManager.signIn(password));
+		accountManager.signIn(password);
 		assertTrue(accountManager.hasDatabaseKey());
 		SecretKey decrypted = accountManager.getDatabaseKey();
 		assertNotNull(decrypted);
@@ -157,7 +172,7 @@ public class AccountManagerImplTest extends BrambleMockTestCase {
 		assertEquals(encryptedKeyHex, loadDatabaseKey(keyFile));
 		assertEquals(encryptedKeyHex, loadDatabaseKey(keyBackupFile));
 
-		assertTrue(accountManager.signIn(password));
+		accountManager.signIn(password);
 		assertTrue(accountManager.hasDatabaseKey());
 		SecretKey decrypted = accountManager.getDatabaseKey();
 		assertNotNull(decrypted);
@@ -239,55 +254,6 @@ public class AccountManagerImplTest extends BrambleMockTestCase {
 		assertFalse(keyBackupFile.exists());
 	}
 
-	@Test
-	public void testAccountExistsReturnsFalseIfDbDirectoryDoesNotExist()
-			throws Exception {
-		storeDatabaseKey(keyFile, encryptedKeyHex);
-		storeDatabaseKey(keyBackupFile, encryptedKeyHex);
-
-		assertFalse(dbDir.exists());
-
-		assertFalse(accountManager.accountExists());
-
-		assertEquals(encryptedKeyHex, loadDatabaseKey(keyFile));
-		assertEquals(encryptedKeyHex, loadDatabaseKey(keyBackupFile));
-		assertFalse(dbDir.exists());
-	}
-
-	@Test
-	public void testAccountExistsReturnsFalseIfDbDirectoryIsNotDirectory()
-			throws Exception {
-		storeDatabaseKey(keyFile, encryptedKeyHex);
-		storeDatabaseKey(keyBackupFile, encryptedKeyHex);
-
-		assertTrue(dbDir.createNewFile());
-		assertFalse(dbDir.isDirectory());
-
-		assertFalse(accountManager.accountExists());
-
-		assertEquals(encryptedKeyHex, loadDatabaseKey(keyFile));
-		assertEquals(encryptedKeyHex, loadDatabaseKey(keyBackupFile));
-		assertTrue(dbDir.exists());
-		assertFalse(dbDir.isDirectory());
-	}
-
-	@Test
-	public void testAccountExistsReturnsTrueIfDbDirectoryIsDirectory()
-			throws Exception {
-		storeDatabaseKey(keyFile, encryptedKeyHex);
-		storeDatabaseKey(keyBackupFile, encryptedKeyHex);
-
-		assertTrue(dbDir.mkdirs());
-		assertTrue(dbDir.isDirectory());
-
-		assertTrue(accountManager.accountExists());
-
-		assertEquals(encryptedKeyHex, loadDatabaseKey(keyFile));
-		assertEquals(encryptedKeyHex, loadDatabaseKey(keyBackupFile));
-		assertTrue(dbDir.exists());
-		assertTrue(dbDir.isDirectory());
-	}
-
 	@Test
 	public void testCreateAccountStoresDbKey() throws Exception {
 		context.checking(new Expectations() {{
@@ -315,26 +281,36 @@ public class AccountManagerImplTest extends BrambleMockTestCase {
 	}
 
 	@Test
-	public void testChangePasswordReturnsFalseIfDbKeyCannotBeLoaded() {
-		assertFalse(accountManager.changePassword(password, newPassword));
+	public void testChangePasswordThrowsExceptionIfDbKeyCannotBeLoaded() {
+		try {
+			accountManager.changePassword(password, newPassword);
+			fail();
+		} catch (DecryptionException expected) {
+			assertEquals(INVALID_CIPHERTEXT, expected.getDecryptionResult());
+		}
 
 		assertFalse(keyFile.exists());
 		assertFalse(keyBackupFile.exists());
 	}
 
 	@Test
-	public void testChangePasswordReturnsFalseIfPasswordIsWrong()
+	public void testChangePasswordThrowsExceptionIfPasswordIsWrong()
 			throws Exception {
 		context.checking(new Expectations() {{
 			oneOf(crypto).decryptWithPassword(encryptedKey, password,
 					keyStrengthener);
-			will(returnValue(null));
+			will(throwException(new DecryptionException(INVALID_PASSWORD)));
 		}});
 
 		storeDatabaseKey(keyFile, encryptedKeyHex);
 		storeDatabaseKey(keyBackupFile, encryptedKeyHex);
 
-		assertFalse(accountManager.changePassword(password, newPassword));
+		try {
+			accountManager.changePassword(password, newPassword);
+			fail();
+		} catch (DecryptionException expected) {
+			assertEquals(INVALID_PASSWORD, expected.getDecryptionResult());
+		}
 
 		assertEquals(encryptedKeyHex, loadDatabaseKey(keyFile));
 		assertEquals(encryptedKeyHex, loadDatabaseKey(keyBackupFile));
@@ -357,7 +333,7 @@ public class AccountManagerImplTest extends BrambleMockTestCase {
 		storeDatabaseKey(keyFile, encryptedKeyHex);
 		storeDatabaseKey(keyBackupFile, encryptedKeyHex);
 
-		assertTrue(accountManager.changePassword(password, newPassword));
+		accountManager.changePassword(password, newPassword);
 
 		assertEquals(newEncryptedKeyHex, loadDatabaseKey(keyFile));
 		assertEquals(newEncryptedKeyHex, loadDatabaseKey(keyBackupFile));
@@ -366,7 +342,7 @@ public class AccountManagerImplTest extends BrambleMockTestCase {
 	private void storeDatabaseKey(File f, String hex) throws IOException {
 		f.getParentFile().mkdirs();
 		FileOutputStream out = new FileOutputStream(f);
-		out.write(hex.getBytes("UTF-8"));
+		out.write(hex.getBytes(Charset.forName("UTF-8")));
 		out.flush();
 		out.close();
 	}
@@ -374,7 +350,7 @@ public class AccountManagerImplTest extends BrambleMockTestCase {
 	@Nullable
 	private String loadDatabaseKey(File f) throws IOException {
 		BufferedReader reader = new BufferedReader(new InputStreamReader(
-				new FileInputStream(f), "UTF-8"));
+				new FileInputStream(f), Charset.forName("UTF-8")));
 		String hex = reader.readLine();
 		reader.close();
 		return hex;

bramble-core/src/test/java/org/briarproject/bramble/crypto/PasswordBasedEncryptionTest.java

@@ -1,25 +1,35 @@
 package org.briarproject.bramble.crypto;
 
+import org.briarproject.bramble.api.crypto.DecryptionException;
+import org.briarproject.bramble.api.crypto.KeyStrengthener;
+import org.briarproject.bramble.api.crypto.SecretKey;
 import org.briarproject.bramble.system.SystemClock;
-import org.briarproject.bramble.test.BrambleTestCase;
+import org.briarproject.bramble.test.BrambleMockTestCase;
 import org.briarproject.bramble.test.TestSecureRandomProvider;
-import org.briarproject.bramble.test.TestUtils;
+import org.jmock.Expectations;
 import org.junit.Test;
 
-import java.util.Random;
-
+import static org.briarproject.bramble.api.crypto.DecryptionResult.INVALID_CIPHERTEXT;
+import static org.briarproject.bramble.api.crypto.DecryptionResult.INVALID_PASSWORD;
+import static org.briarproject.bramble.api.crypto.DecryptionResult.KEY_STRENGTHENER_ERROR;
+import static org.briarproject.bramble.test.TestUtils.getRandomBytes;
+import static org.briarproject.bramble.test.TestUtils.getSecretKey;
 import static org.junit.Assert.assertArrayEquals;
-import static org.junit.Assert.assertNull;
+import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.fail;
 
-public class PasswordBasedEncryptionTest extends BrambleTestCase {
+public class PasswordBasedEncryptionTest extends BrambleMockTestCase {
+
+	private final KeyStrengthener keyStrengthener =
+			context.mock(KeyStrengthener.class);
 
 	private final CryptoComponentImpl crypto =
 			new CryptoComponentImpl(new TestSecureRandomProvider(),
 					new ScryptKdf(new SystemClock()));
 
 	@Test
-	public void testEncryptionAndDecryption() {
-		byte[] input = TestUtils.getRandomBytes(1234);
+	public void testEncryptionAndDecryption() throws Exception {
+		byte[] input = getRandomBytes(1234);
 		String password = "password";
 		byte[] ciphertext = crypto.encryptWithPassword(input, password, null);
 		byte[] output = crypto.decryptWithPassword(ciphertext, password, null);
@@ -27,14 +37,80 @@ public class PasswordBasedEncryptionTest extends BrambleTestCase {
 	}
 
 	@Test
-	public void testInvalidCiphertextReturnsNull() {
-		byte[] input = TestUtils.getRandomBytes(1234);
+	public void testInvalidFormatVersionThrowsException() {
+		byte[] input = getRandomBytes(1234);
 		String password = "password";
 		byte[] ciphertext = crypto.encryptWithPassword(input, password, null);
-		// Modify the ciphertext
-		int position = new Random().nextInt(ciphertext.length);
-		ciphertext[position] = (byte) (ciphertext[position] ^ 0xFF);
-		byte[] output = crypto.decryptWithPassword(ciphertext, password, null);
-		assertNull(output);
+
+		// Modify the format version
+		ciphertext[0] ^= (byte) 0xFF;
+		try {
+			crypto.decryptWithPassword(ciphertext, password, null);
+			fail();
+		} catch (DecryptionException expected) {
+			assertEquals(INVALID_CIPHERTEXT, expected.getDecryptionResult());
+		}
+	}
+
+	@Test
+	public void testInvalidPasswordThrowsException() {
+		byte[] input = getRandomBytes(1234);
+		byte[] ciphertext = crypto.encryptWithPassword(input, "password", null);
+
+		// Try to decrypt with the wrong password
+		try {
+			crypto.decryptWithPassword(ciphertext, "wrong", null);
+			fail();
+		} catch (DecryptionException expected) {
+			assertEquals(INVALID_PASSWORD, expected.getDecryptionResult());
+		}
+	}
+
+	@Test
+	public void testMissingKeyStrengthenerThrowsException() {
+		SecretKey strengthened = getSecretKey();
+		context.checking(new Expectations() {{
+			oneOf(keyStrengthener).strengthenKey(with(any(SecretKey.class)));
+			will(returnValue(strengthened));
+		}});
+
+		// Use the key strengthener during encryption
+		byte[] input = getRandomBytes(1234);
+		String password = "password";
+		byte[] ciphertext =
+				crypto.encryptWithPassword(input, password, keyStrengthener);
+
+		// The key strengthener is missing during decryption
+		try {
+			crypto.decryptWithPassword(ciphertext, password, null);
+			fail();
+		} catch (DecryptionException expected) {
+			assertEquals(KEY_STRENGTHENER_ERROR, expected.getDecryptionResult());
+		}
+	}
+
+	@Test
+	public void testKeyStrengthenerFailureThrowsException() {
+		SecretKey strengthened = getSecretKey();
+		context.checking(new Expectations() {{
+			oneOf(keyStrengthener).strengthenKey(with(any(SecretKey.class)));
+			will(returnValue(strengthened));
+			oneOf(keyStrengthener).isInitialised();
+			will(returnValue(false));
+		}});
+
+		// Use the key strengthener during encryption
+		byte[] input = getRandomBytes(1234);
+		String password = "password";
+		byte[] ciphertext =
+				crypto.encryptWithPassword(input, password, keyStrengthener);
+
+		// The key strengthener fails during decryption
+		try {
+			crypto.decryptWithPassword(ciphertext, password, keyStrengthener);
+			fail();
+		} catch (DecryptionException expected) {
+			assertEquals(KEY_STRENGTHENER_ERROR, expected.getDecryptionResult());
+		}
 	}
 }

bramble-core/src/test/java/org/briarproject/bramble/io/TimeoutInputStreamTest.java

@@ -0,0 +1,143 @@
+package org.briarproject.bramble.io;
+
+import org.briarproject.bramble.test.BrambleTestCase;
+import org.briarproject.bramble.test.SettableClock;
+import org.junit.Before;
+import org.junit.Test;
+
+import java.io.IOException;
+import java.io.InputStream;
+import java.util.concurrent.CountDownLatch;
+import java.util.concurrent.atomic.AtomicBoolean;
+import java.util.concurrent.atomic.AtomicLong;
+
+import static java.util.concurrent.TimeUnit.MINUTES;
+import static java.util.concurrent.TimeUnit.SECONDS;
+import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertFalse;
+import static org.junit.Assert.assertTrue;
+import static org.junit.Assert.fail;
+
+public class TimeoutInputStreamTest extends BrambleTestCase {
+
+	private static final long TIMEOUT_MS = MINUTES.toMillis(1);
+
+	private final long now = System.currentTimeMillis();
+
+	private AtomicLong time;
+	private UnresponsiveInputStream in;
+	private AtomicBoolean listenerCalled;
+	private TimeoutInputStream stream;
+	private CountDownLatch readReturned;
+
+	@Before
+	public void setUp() {
+		time = new AtomicLong(now);
+		in = new UnresponsiveInputStream();
+		listenerCalled = new AtomicBoolean(false);
+		stream = new TimeoutInputStream(new SettableClock(time), in,
+				TIMEOUT_MS, stream -> listenerCalled.set(true));
+		readReturned = new CountDownLatch(1);
+	}
+
+	@Test
+	public void testTimeoutIsReportedIfReadDoesNotReturn() throws Exception {
+		startReading();
+		try {
+			// The stream should not report a timeout
+			assertFalse(stream.hasTimedOut());
+
+			// Time passes
+			time.set(now + TIMEOUT_MS);
+
+			// The stream still shouldn't report a timeout
+			assertFalse(stream.hasTimedOut());
+
+			// Time passes
+			time.set(now + TIMEOUT_MS + 1);
+
+			// The stream should report a timeout
+			assertTrue(stream.hasTimedOut());
+
+			// The listener should not have been called yet
+			assertFalse(listenerCalled.get());
+
+			// Close the stream
+			stream.close();
+
+			// The listener should have been called
+			assertTrue(listenerCalled.get());
+		} finally {
+			// Allow the read to return
+			in.readFinished.countDown();
+		}
+	}
+
+	@Test
+	public void testTimeoutIsNotReportedIfReadReturns() throws Exception {
+		startReading();
+		try {
+			// The stream should not report a timeout
+			assertFalse(stream.hasTimedOut());
+
+			// Time passes
+			time.set(now + TIMEOUT_MS);
+
+			// The stream still shouldn't report a timeout
+			assertFalse(stream.hasTimedOut());
+
+			// Allow the read to finish and wait for it to return
+			in.readFinished.countDown();
+			readReturned.await(10, SECONDS);
+
+			// Time passes
+			time.set(now + TIMEOUT_MS + 1);
+
+			// The stream should not report a timeout as the read has returned
+			assertFalse(stream.hasTimedOut());
+
+			// The listener should not have been called yet
+			assertFalse(listenerCalled.get());
+
+			// Close the stream
+			stream.close();
+
+			// The listener should have been called
+			assertTrue(listenerCalled.get());
+		} finally {
+			// Allow the read to return in case an assertion was thrown
+			in.readFinished.countDown();
+		}
+	}
+
+	private void startReading() throws Exception {
+		// Start a background thread to read from the unresponsive stream
+		new Thread(() -> {
+			try {
+				assertEquals(123, stream.read());
+				readReturned.countDown();
+			} catch (IOException e) {
+				fail();
+			}
+		}).start();
+		// Wait for the background thread to start reading
+		assertTrue(in.readStarted.await(10, SECONDS));
+	}
+
+	private class UnresponsiveInputStream extends InputStream {
+
+		private final CountDownLatch readStarted = new CountDownLatch(1);
+		private final CountDownLatch readFinished = new CountDownLatch(1);
+
+		@Override
+		public int read() throws IOException {
+			readStarted.countDown();
+			try {
+				readFinished.await();
+				return 123;
+			} catch (InterruptedException e) {
+				throw new IOException(e);
+			}
+		}
+	}
+}

bramble-core/src/test/java/org/briarproject/bramble/plugin/PollerImplTest.java

@@ -13,8 +13,8 @@ import org.briarproject.bramble.api.plugin.duplex.DuplexPlugin;
 import org.briarproject.bramble.api.plugin.duplex.DuplexTransportConnection;
 import org.briarproject.bramble.api.plugin.event.ConnectionClosedEvent;
 import org.briarproject.bramble.api.plugin.event.ConnectionOpenedEvent;
-import org.briarproject.bramble.api.plugin.event.TransportActiveEvent;
-import org.briarproject.bramble.api.plugin.event.TransportInactiveEvent;
+import org.briarproject.bramble.api.plugin.event.TransportDisabledEvent;
+import org.briarproject.bramble.api.plugin.event.TransportEnabledEvent;
 import org.briarproject.bramble.api.plugin.simplex.SimplexPlugin;
 import org.briarproject.bramble.api.properties.TransportProperties;
 import org.briarproject.bramble.api.properties.TransportPropertyManager;
@@ -322,7 +322,7 @@ public class PollerImplTest extends BrambleMockTestCase {
 	}
 
 	@Test
-	public void testPollsOnTransportActivated() throws Exception {
+	public void testPollsOnTransportEnabled() throws Exception {
 		DuplexPlugin plugin = context.mock(DuplexPlugin.class);
 
 		context.checking(new Expectations() {{
@@ -361,7 +361,7 @@ public class PollerImplTest extends BrambleMockTestCase {
 					pairOf(equal(properties), any(ConnectionHandler.class)))));
 		}});
 
-		poller.eventOccurred(new TransportActiveEvent(transportId));
+		poller.eventOccurred(new TransportEnabledEvent(transportId));
 	}
 
 	@Test
@@ -402,11 +402,11 @@ public class PollerImplTest extends BrambleMockTestCase {
 			// All contacts are connected, so don't poll the plugin
 		}});
 
-		poller.eventOccurred(new TransportActiveEvent(transportId));
+		poller.eventOccurred(new TransportEnabledEvent(transportId));
 	}
 
 	@Test
-	public void testCancelsPollingOnTransportDeactivated() {
+	public void testCancelsPollingOnTransportDisabled() {
 		Plugin plugin = context.mock(Plugin.class);
 
 		context.checking(new Expectations() {{
@@ -424,11 +424,11 @@ public class PollerImplTest extends BrambleMockTestCase {
 			oneOf(scheduler).schedule(with(any(Runnable.class)), with(0L),
 					with(MILLISECONDS));
 			will(returnValue(future));
-			// The plugin is deactivated before the task runs - cancel the task
+			// The plugin is disabled before the task runs - cancel the task
 			oneOf(future).cancel(false);
 		}});
 
-		poller.eventOccurred(new TransportActiveEvent(transportId));
-		poller.eventOccurred(new TransportInactiveEvent(transportId));
+		poller.eventOccurred(new TransportEnabledEvent(transportId));
+		poller.eventOccurred(new TransportDisabledEvent(transportId));
 	}
 }

bramble-core/src/test/java/org/briarproject/bramble/plugin/bluetooth/BluetoothConnectionLimiterImplTest.java

@@ -0,0 +1,182 @@
+package org.briarproject.bramble.plugin.bluetooth;
+
+import org.briarproject.bramble.api.event.EventBus;
+import org.briarproject.bramble.api.plugin.duplex.DuplexTransportConnection;
+import org.briarproject.bramble.api.sync.event.CloseSyncConnectionsEvent;
+import org.briarproject.bramble.api.system.Clock;
+import org.briarproject.bramble.test.BrambleMockTestCase;
+import org.briarproject.bramble.test.SettableClock;
+import org.jmock.Expectations;
+import org.junit.Before;
+import org.junit.Test;
+
+import java.util.concurrent.atomic.AtomicLong;
+
+import static org.briarproject.bramble.plugin.bluetooth.BluetoothConnectionLimiter.MIN_ATTEMPT_INTERVAL_MS;
+import static org.briarproject.bramble.plugin.bluetooth.BluetoothConnectionLimiter.STABILITY_PERIOD_MS;
+import static org.junit.Assert.assertFalse;
+import static org.junit.Assert.assertTrue;
+
+public class BluetoothConnectionLimiterImplTest extends BrambleMockTestCase {
+
+	private final EventBus eventBus = context.mock(EventBus.class);
+
+	private final DuplexTransportConnection conn1 =
+			context.mock(DuplexTransportConnection.class, "conn1");
+	private final DuplexTransportConnection conn2 =
+			context.mock(DuplexTransportConnection.class, "conn2");
+	private final DuplexTransportConnection conn3 =
+			context.mock(DuplexTransportConnection.class, "conn3");
+
+	private final long now = System.currentTimeMillis();
+
+	private AtomicLong time;
+	private BluetoothConnectionLimiter limiter;
+
+	@Before
+	public void setUp() {
+		time = new AtomicLong(now);
+		Clock clock = new SettableClock(time);
+		limiter = new BluetoothConnectionLimiterImpl(eventBus, clock);
+	}
+
+	@Test
+	public void testLimiterDoesNotAllowContactConnectionsDuringKeyAgreement() {
+		assertTrue(limiter.canOpenContactConnection());
+
+		expectCloseSyncConnectionsEvent();
+		limiter.keyAgreementStarted();
+
+		assertFalse(limiter.canOpenContactConnection());
+
+		limiter.keyAgreementEnded();
+
+		assertTrue(limiter.canOpenContactConnection());
+	}
+
+	@Test
+	public void testLimiterAllowsAttemptToRaiseLimitAtStartup() {
+		// First outgoing connection is allowed - we're below the limit of 1
+		assertTrue(limiter.canOpenContactConnection());
+		assertTrue(limiter.contactConnectionOpened(conn1, false));
+
+		// Second outgoing connection is allowed - it's time to try raising
+		// the limit to 2
+		assertTrue(limiter.canOpenContactConnection());
+		assertTrue(limiter.contactConnectionOpened(conn2, false));
+
+		// Third outgoing connection is not allowed - we're above the limit of 1
+		assertFalse(limiter.canOpenContactConnection());
+	}
+
+	@Test
+	public void testLimiterAllowsThirdConnectionAfterFirstTwoAreClosed() {
+		// First outgoing connection is allowed - we're below the limit of 1
+		assertTrue(limiter.canOpenContactConnection());
+		assertTrue(limiter.contactConnectionOpened(conn1, false));
+
+		// Second outgoing connection is allowed - it's time to try raising
+		// the limit to 2
+		assertTrue(limiter.canOpenContactConnection());
+		assertTrue(limiter.contactConnectionOpened(conn2, false));
+
+		// Third outgoing connection is not allowed - we're above the limit of 1
+		assertFalse(limiter.canOpenContactConnection());
+
+		// Close the first connection
+		limiter.connectionClosed(conn1, false);
+
+		// Third outgoing connection is not allowed - we're at the limit of 1
+		assertFalse(limiter.canOpenContactConnection());
+
+		// Close the second connection
+		limiter.connectionClosed(conn2, false);
+
+		// Third outgoing connection is allowed - we're below the limit of 1
+		assertTrue(limiter.canOpenContactConnection());
+		assertTrue(limiter.contactConnectionOpened(conn3, false));
+	}
+
+	@Test
+	public void testLimiterRaisesLimitWhenConnectionsAreStable() {
+		// First outgoing connection is allowed - we're below the limit of 1
+		assertTrue(limiter.canOpenContactConnection());
+		assertTrue(limiter.contactConnectionOpened(conn1, false));
+
+		// Second outgoing connection is allowed - it's time to try raising
+		// the limit to 2
+		assertTrue(limiter.canOpenContactConnection());
+		assertTrue(limiter.contactConnectionOpened(conn2, false));
+
+		// Third outgoing connection is not allowed - we're above the limit of 1
+		assertFalse(limiter.canOpenContactConnection());
+
+		// Time passes
+		time.set(now + STABILITY_PERIOD_MS);
+
+		// Third outgoing connection is still not allowed - first two are now
+		// stable so limit is raised to 2, but we're already at the new limit
+		assertFalse(limiter.canOpenContactConnection());
+
+		// Time passes
+		time.set(now + MIN_ATTEMPT_INTERVAL_MS);
+
+		// Third outgoing connection is allowed - it's time to try raising
+		// the limit to 3
+		assertTrue(limiter.canOpenContactConnection());
+		assertTrue(limiter.contactConnectionOpened(conn3, false));
+
+		// Fourth outgoing connection is not allowed - we're above the limit
+		// of 2
+		assertFalse(limiter.canOpenContactConnection());
+	}
+
+	@Test
+	public void testLimiterIncreasesIntervalWhenConnectionFailsAboveLimit() {
+		// First outgoing connection is allowed - we're below the limit of 1
+		assertTrue(limiter.canOpenContactConnection());
+		assertTrue(limiter.contactConnectionOpened(conn1, false));
+
+		// Time passes
+		time.set(now + 1);
+
+		// Second outgoing connection is allowed - it's time to try raising
+		// the limit to 2
+		assertTrue(limiter.canOpenContactConnection());
+		assertTrue(limiter.contactConnectionOpened(conn2, false));
+
+		// Time passes - the first connection is stable, the second isn't
+		time.set(now + STABILITY_PERIOD_MS);
+
+		// First connection fails. The second connection isn't stable yet, so
+		// the limiter considers this a failed attempt and doubles the interval
+		// between attempts
+		limiter.connectionClosed(conn1, true);
+
+		// Third outgoing connection is not allowed - we're still at the limit
+		// of 1
+		assertFalse(limiter.canOpenContactConnection());
+
+		// Time passes - nearly time for the second attempt
+		time.set(now + MIN_ATTEMPT_INTERVAL_MS * 2);
+
+		// Third outgoing connection is not allowed - we're still at the limit
+		// of 1
+		assertFalse(limiter.canOpenContactConnection());
+
+		// Time passes - now it's time for the second attempt
+		time.set(now + 1 + MIN_ATTEMPT_INTERVAL_MS * 2);
+
+		// Third outgoing connection is allowed - it's time to try raising the
+		// limit to 2 again
+		assertTrue(limiter.canOpenContactConnection());
+		assertTrue(limiter.contactConnectionOpened(conn3, false));
+	}
+
+	private void expectCloseSyncConnectionsEvent() {
+		context.checking(new Expectations() {{
+			oneOf(eventBus).broadcast(with(any(
+					CloseSyncConnectionsEvent.class)));
+		}});
+	}
+}

bramble-core/src/test/java/org/briarproject/bramble/plugin/tcp/LanTcpPluginTest.java

@@ -4,16 +4,14 @@ import org.briarproject.bramble.api.data.BdfList;
 import org.briarproject.bramble.api.keyagreement.KeyAgreementListener;
 import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
 import org.briarproject.bramble.api.plugin.Backoff;
-import org.briarproject.bramble.api.plugin.Plugin.State;
 import org.briarproject.bramble.api.plugin.PluginCallback;
 import org.briarproject.bramble.api.plugin.TransportConnectionReader;
 import org.briarproject.bramble.api.plugin.TransportConnectionWriter;
-import org.briarproject.bramble.api.plugin.duplex.DuplexPlugin;
 import org.briarproject.bramble.api.plugin.duplex.DuplexTransportConnection;
 import org.briarproject.bramble.api.properties.TransportProperties;
 import org.briarproject.bramble.api.settings.Settings;
-import org.briarproject.bramble.plugin.tcp.LanTcpPlugin.LanAddressComparator;
 import org.briarproject.bramble.test.BrambleTestCase;
+import org.junit.Before;
 import org.junit.Test;
 
 import java.io.IOException;
@@ -23,7 +21,6 @@ import java.net.InetSocketAddress;
 import java.net.NetworkInterface;
 import java.net.ServerSocket;
 import java.net.Socket;
-import java.util.Comparator;
 import java.util.concurrent.CountDownLatch;
 import java.util.concurrent.ExecutorService;
 import java.util.concurrent.atomic.AtomicBoolean;
@@ -34,57 +31,89 @@ import static java.util.concurrent.Executors.newCachedThreadPool;
 import static java.util.concurrent.TimeUnit.SECONDS;
 import static org.briarproject.bramble.api.keyagreement.KeyAgreementConstants.COMMIT_LENGTH;
 import static org.briarproject.bramble.api.keyagreement.KeyAgreementConstants.TRANSPORT_ID_LAN;
-import static org.briarproject.bramble.api.plugin.Plugin.PREF_PLUGIN_ENABLE;
+import static org.briarproject.bramble.plugin.tcp.LanTcpPlugin.areAddressesInSameNetwork;
 import static org.junit.Assert.assertEquals;
 import static org.junit.Assert.assertFalse;
 import static org.junit.Assert.assertNotNull;
 import static org.junit.Assert.assertTrue;
+import static org.junit.Assume.assumeTrue;
 
 public class LanTcpPluginTest extends BrambleTestCase {
 
 	private final Backoff backoff = new TestBackoff();
 	private final ExecutorService ioExecutor = newCachedThreadPool();
 
+	private Callback callback = null;
+	private LanTcpPlugin plugin = null;
+
+	@Before
+	public void setUp() {
+		callback = new Callback();
+		plugin = new LanTcpPlugin(ioExecutor, backoff, callback, 0, 0, 1000) {
+			@Override
+			protected boolean canConnectToOwnAddress() {
+				return true;
+			}
+		};
+	}
+
 	@Test
-	public void testAddressesAreOnSameLan() {
-		Callback callback = new Callback();
-		LanTcpPlugin plugin = new LanTcpPlugin(ioExecutor, backoff, callback,
-				0, 0);
-		// Local and remote in 10.0.0.0/8 should return true
-		assertTrue(plugin.addressesAreOnSameLan(makeAddress(10, 0, 0, 0),
-				makeAddress(10, 255, 255, 255)));
-		// Local and remote in 172.16.0.0/12 should return true
-		assertTrue(plugin.addressesAreOnSameLan(makeAddress(172, 16, 0, 0),
-				makeAddress(172, 31, 255, 255)));
-		// Local and remote in 192.168.0.0/16 should return true
-		assertTrue(plugin.addressesAreOnSameLan(makeAddress(192, 168, 0, 0),
-				makeAddress(192, 168, 255, 255)));
-		// Local and remote in 169.254.0.0/16 (link-local) should return true
-		assertTrue(plugin.addressesAreOnSameLan(makeAddress(169, 254, 0, 0),
-				makeAddress(169, 254, 255, 255)));
-		// Local and remote in different recognised prefixes should return false
-		assertFalse(plugin.addressesAreOnSameLan(makeAddress(10, 0, 0, 0),
-				makeAddress(172, 31, 255, 255)));
-		assertFalse(plugin.addressesAreOnSameLan(makeAddress(10, 0, 0, 0),
-				makeAddress(192, 168, 255, 255)));
-		assertFalse(plugin.addressesAreOnSameLan(makeAddress(172, 16, 0, 0),
-				makeAddress(10, 255, 255, 255)));
-		assertFalse(plugin.addressesAreOnSameLan(makeAddress(172, 16, 0, 0),
-				makeAddress(192, 168, 255, 255)));
-		assertFalse(plugin.addressesAreOnSameLan(makeAddress(192, 168, 0, 0),
-				makeAddress(10, 255, 255, 255)));
-		assertFalse(plugin.addressesAreOnSameLan(makeAddress(192, 168, 0, 0),
-				makeAddress(172, 31, 255, 255)));
-		// Remote prefix unrecognised should return false
-		assertFalse(plugin.addressesAreOnSameLan(makeAddress(10, 0, 0, 0),
-				makeAddress(1, 2, 3, 4)));
-		assertFalse(plugin.addressesAreOnSameLan(makeAddress(172, 16, 0, 0),
-				makeAddress(1, 2, 3, 4)));
-		assertFalse(plugin.addressesAreOnSameLan(makeAddress(192, 168, 0, 0),
-				makeAddress(1, 2, 3, 4)));
-		// Both prefixes unrecognised should return true (could be link-local)
-		assertTrue(plugin.addressesAreOnSameLan(makeAddress(1, 2, 3, 4),
-				makeAddress(5, 6, 7, 8)));
+	public void testAreAddressesInSameNetwork() {
+		// Local and remote in 10.0.0.0/8
+		assertTrue(areAddressesInSameNetwork(makeAddress(10, 0, 0, 0),
+				makeAddress(10, 255, 255, 255), 8));
+		assertFalse(areAddressesInSameNetwork(makeAddress(10, 0, 0, 0),
+				makeAddress(10, 255, 255, 255), 9));
+
+		// Local and remote in 172.16.0.0/12
+		assertTrue(areAddressesInSameNetwork(makeAddress(172, 16, 0, 0),
+				makeAddress(172, 31, 255, 255), 12));
+		assertFalse(areAddressesInSameNetwork(makeAddress(172, 16, 0, 0),
+				makeAddress(172, 31, 255, 255), 13));
+
+		// Local and remote in 192.168.0.0/16
+		assertTrue(areAddressesInSameNetwork(makeAddress(192, 168, 0, 0),
+				makeAddress(192, 168, 255, 255), 16));
+		assertFalse(areAddressesInSameNetwork(makeAddress(192, 168, 0, 0),
+				makeAddress(192, 168, 255, 255), 17));
+
+		// Local and remote in 169.254.0.0/16
+		assertTrue(areAddressesInSameNetwork(makeAddress(169, 254, 0, 0),
+				makeAddress(169, 254, 255, 255), 16));
+		assertFalse(areAddressesInSameNetwork(makeAddress(169, 254, 0, 0),
+				makeAddress(169, 254, 255, 255), 17));
+
+		// Local in 10.0.0.0/8, remote in a different network
+		assertFalse(areAddressesInSameNetwork(makeAddress(10, 0, 0, 0),
+				makeAddress(172, 31, 255, 255), 8));
+		assertFalse(areAddressesInSameNetwork(makeAddress(10, 0, 0, 0),
+				makeAddress(192, 168, 255, 255), 8));
+		assertFalse(areAddressesInSameNetwork(makeAddress(10, 0, 0, 0),
+				makeAddress(169, 254, 255, 255), 8));
+
+		// Local in 172.16.0.0/12, remote in a different network
+		assertFalse(areAddressesInSameNetwork(makeAddress(172, 16, 0, 0),
+				makeAddress(10, 255, 255, 255), 12));
+		assertFalse(areAddressesInSameNetwork(makeAddress(172, 16, 0, 0),
+				makeAddress(192, 168, 255, 255), 12));
+		assertFalse(areAddressesInSameNetwork(makeAddress(172, 16, 0, 0),
+				makeAddress(169, 254, 255, 255), 12));
+
+		// Local in 192.168.0.0/16, remote in a different network
+		assertFalse(areAddressesInSameNetwork(makeAddress(192, 168, 0, 0),
+				makeAddress(10, 255, 255, 255), 16));
+		assertFalse(areAddressesInSameNetwork(makeAddress(192, 168, 0, 0),
+				makeAddress(172, 31, 255, 255), 16));
+		assertFalse(areAddressesInSameNetwork(makeAddress(192, 168, 0, 0),
+				makeAddress(169, 254, 255, 255), 16));
+
+		// Local in 169.254.0.0/16, remote in a different network
+		assertFalse(areAddressesInSameNetwork(makeAddress(169, 254, 0, 0),
+				makeAddress(10, 255, 255, 255), 16));
+		assertFalse(areAddressesInSameNetwork(makeAddress(169, 254, 0, 0),
+				makeAddress(172, 31, 255, 255), 16));
+		assertFalse(areAddressesInSameNetwork(makeAddress(169, 254, 0, 0),
+				makeAddress(192, 168, 255, 255), 16));
 	}
 
 	private byte[] makeAddress(int... parts) {
@@ -95,13 +124,7 @@ public class LanTcpPluginTest extends BrambleTestCase {
 
 	@Test
 	public void testIncomingConnection() throws Exception {
-		if (!systemHasLocalIpv4Address()) {
-			System.err.println("WARNING: Skipping test, no local IPv4 address");
-			return;
-		}
-		Callback callback = new Callback();
-		DuplexPlugin plugin = new LanTcpPlugin(ioExecutor, backoff, callback,
-				0, 0);
+		assumeTrue(systemHasLocalIpv4Address());
 		plugin.start();
 		// The plugin should have bound a socket and stored the port number
 		assertTrue(callback.propertiesLatch.await(5, SECONDS));
@@ -130,13 +153,7 @@ public class LanTcpPluginTest extends BrambleTestCase {
 
 	@Test
 	public void testOutgoingConnection() throws Exception {
-		if (!systemHasLocalIpv4Address()) {
-			System.err.println("WARNING: Skipping test, no local IPv4 address");
-			return;
-		}
-		Callback callback = new Callback();
-		DuplexPlugin plugin = new LanTcpPlugin(ioExecutor, backoff, callback,
-				0, 0);
+		assumeTrue(systemHasLocalIpv4Address());
 		plugin.start();
 		// The plugin should have bound a socket and stored the port number
 		assertTrue(callback.propertiesLatch.await(5, SECONDS));
@@ -179,13 +196,7 @@ public class LanTcpPluginTest extends BrambleTestCase {
 
 	@Test
 	public void testIncomingKeyAgreementConnection() throws Exception {
-		if (!systemHasLocalIpv4Address()) {
-			System.err.println("WARNING: Skipping test, no local IPv4 address");
-			return;
-		}
-		Callback callback = new Callback();
-		DuplexPlugin plugin = new LanTcpPlugin(ioExecutor, backoff, callback,
-				0, 0);
+		assumeTrue(systemHasLocalIpv4Address());
 		plugin.start();
 		assertTrue(callback.propertiesLatch.await(5, SECONDS));
 		KeyAgreementListener kal =
@@ -227,13 +238,7 @@ public class LanTcpPluginTest extends BrambleTestCase {
 
 	@Test
 	public void testOutgoingKeyAgreementConnection() throws Exception {
-		if (!systemHasLocalIpv4Address()) {
-			System.err.println("WARNING: Skipping test, no local IPv4 address");
-			return;
-		}
-		Callback callback = new Callback();
-		DuplexPlugin plugin = new LanTcpPlugin(ioExecutor, backoff, callback,
-				0, 0);
+		assumeTrue(systemHasLocalIpv4Address());
 		plugin.start();
 		// The plugin should have bound a socket and stored the port number
 		assertTrue(callback.propertiesLatch.await(5, SECONDS));
@@ -278,63 +283,12 @@ public class LanTcpPluginTest extends BrambleTestCase {
 		plugin.stop();
 	}
 
-	@Test
-	public void testComparatorPrefersNonZeroPorts() {
-		Comparator<InetSocketAddress> comparator = new LanAddressComparator();
-		InetSocketAddress nonZero = new InetSocketAddress("1.2.3.4", 1234);
-		InetSocketAddress zero = new InetSocketAddress("1.2.3.4", 0);
-
-		assertEquals(0, comparator.compare(nonZero, nonZero));
-		assertTrue(comparator.compare(nonZero, zero) < 0);
-
-		assertTrue(comparator.compare(zero, nonZero) > 0);
-		assertEquals(0, comparator.compare(zero, zero));
-	}
-
-	@Test
-	public void testComparatorPrefersLongerPrefixes() {
-		Comparator<InetSocketAddress> comparator = new LanAddressComparator();
-		InetSocketAddress prefix192 = new InetSocketAddress("192.168.0.1", 0);
-		InetSocketAddress prefix172 = new InetSocketAddress("172.16.0.1", 0);
-		InetSocketAddress prefix10 = new InetSocketAddress("10.0.0.1", 0);
-
-		assertEquals(0, comparator.compare(prefix192, prefix192));
-		assertTrue(comparator.compare(prefix192, prefix172) < 0);
-		assertTrue(comparator.compare(prefix192, prefix10) < 0);
-
-		assertTrue(comparator.compare(prefix172, prefix192) > 0);
-		assertEquals(0, comparator.compare(prefix172, prefix172));
-		assertTrue(comparator.compare(prefix172, prefix10) < 0);
-
-		assertTrue(comparator.compare(prefix10, prefix192) > 0);
-		assertTrue(comparator.compare(prefix10, prefix172) > 0);
-		assertEquals(0, comparator.compare(prefix10, prefix10));
-	}
-
-	@Test
-	public void testComparatorPrefersSiteLocalToLinkLocal() {
-		Comparator<InetSocketAddress> comparator = new LanAddressComparator();
-		InetSocketAddress prefix192 = new InetSocketAddress("192.168.0.1", 0);
-		InetSocketAddress prefix172 = new InetSocketAddress("172.16.0.1", 0);
-		InetSocketAddress prefix10 = new InetSocketAddress("10.0.0.1", 0);
-		InetSocketAddress linkLocal = new InetSocketAddress("169.254.0.1", 0);
-
-		assertTrue(comparator.compare(prefix192, linkLocal) < 0);
-		assertTrue(comparator.compare(prefix172, linkLocal) < 0);
-		assertTrue(comparator.compare(prefix10, linkLocal) < 0);
-
-		assertTrue(comparator.compare(linkLocal, prefix192) > 0);
-		assertTrue(comparator.compare(linkLocal, prefix172) > 0);
-		assertTrue(comparator.compare(linkLocal, prefix10) > 0);
-		assertEquals(0, comparator.compare(linkLocal, linkLocal));
-	}
-
-	@SuppressWarnings("BooleanMethodIsAlwaysInverted")
 	private boolean systemHasLocalIpv4Address() throws Exception {
 		for (NetworkInterface i : list(getNetworkInterfaces())) {
 			for (InetAddress a : list(i.getInetAddresses())) {
-				if (a instanceof Inet4Address)
+				if (a instanceof Inet4Address) {
 					return a.isLinkLocalAddress() || a.isSiteLocalAddress();
+				}
 			}
 		}
 		return false;
@@ -343,18 +297,15 @@ public class LanTcpPluginTest extends BrambleTestCase {
 	@NotNullByDefault
 	private static class Callback implements PluginCallback {
 
-		private final CountDownLatch propertiesLatch = new CountDownLatch(1);
+		// Properties will be stored twice: the preferred port at startup,
+		// and the IP:port when the server socket is bound
+		private final CountDownLatch propertiesLatch = new CountDownLatch(2);
 		private final CountDownLatch connectionsLatch = new CountDownLatch(1);
 		private final TransportProperties local = new TransportProperties();
-		private final Settings settings = new Settings();
-
-		private Callback() {
-			settings.putBoolean(PREF_PLUGIN_ENABLE, true);
-		}
 
 		@Override
 		public Settings getSettings() {
-			return settings;
+			return new Settings();
 		}
 
 		@Override
@@ -373,7 +324,11 @@ public class LanTcpPluginTest extends BrambleTestCase {
 		}
 
 		@Override
-		public void pluginStateChanged(State newState) {
+		public void transportEnabled() {
+		}
+
+		@Override
+		public void transportDisabled() {
 		}
 
 		@Override

bramble-core/src/test/java/org/briarproject/bramble/properties/TransportPropertyManagerImplTest.java

@@ -24,14 +24,18 @@ import org.briarproject.bramble.test.DbExpectations;
 import org.jmock.Expectations;
 import org.junit.Test;
 
-import java.util.Collections;
 import java.util.LinkedHashMap;
 import java.util.List;
 import java.util.Map;
 
 import static java.util.Arrays.asList;
+import static java.util.Collections.emptyMap;
 import static java.util.Collections.singletonList;
 import static java.util.Collections.singletonMap;
+import static org.briarproject.bramble.api.properties.TransportPropertyConstants.GROUP_KEY_DISCOVERED;
+import static org.briarproject.bramble.api.properties.TransportPropertyConstants.MSG_KEY_LOCAL;
+import static org.briarproject.bramble.api.properties.TransportPropertyConstants.MSG_KEY_TRANSPORT_ID;
+import static org.briarproject.bramble.api.properties.TransportPropertyConstants.MSG_KEY_VERSION;
 import static org.briarproject.bramble.api.properties.TransportPropertyManager.CLIENT_ID;
 import static org.briarproject.bramble.api.properties.TransportPropertyManager.MAJOR_VERSION;
 import static org.briarproject.bramble.api.sync.Group.Visibility.SHARED;
@@ -186,25 +190,25 @@ public class TransportPropertyManagerImplTest extends BrambleMockTestCase {
 		Message message = getMessage(contactGroupId);
 		Metadata meta = new Metadata();
 		BdfDictionary metaDictionary = BdfDictionary.of(
-				new BdfEntry("transportId", "foo"),
-				new BdfEntry("version", 2),
-				new BdfEntry("local", false)
+				new BdfEntry(MSG_KEY_TRANSPORT_ID, "foo"),
+				new BdfEntry(MSG_KEY_VERSION, 2),
+				new BdfEntry(MSG_KEY_LOCAL, false)
 		);
 		Map<MessageId, BdfDictionary> messageMetadata =
 				new LinkedHashMap<>();
 		// A remote update for another transport should be ignored
 		MessageId barUpdateId = new MessageId(getRandomId());
 		messageMetadata.put(barUpdateId, BdfDictionary.of(
-				new BdfEntry("transportId", "bar"),
-				new BdfEntry("version", 1),
-				new BdfEntry("local", false)
+				new BdfEntry(MSG_KEY_TRANSPORT_ID, "bar"),
+				new BdfEntry(MSG_KEY_VERSION, 1),
+				new BdfEntry(MSG_KEY_LOCAL, false)
 		));
 		// A local update for the same transport should be ignored
 		MessageId localUpdateId = new MessageId(getRandomId());
 		messageMetadata.put(localUpdateId, BdfDictionary.of(
-				new BdfEntry("transportId", "foo"),
-				new BdfEntry("version", 1),
-				new BdfEntry("local", true)
+				new BdfEntry(MSG_KEY_TRANSPORT_ID, "foo"),
+				new BdfEntry(MSG_KEY_VERSION, 1),
+				new BdfEntry(MSG_KEY_LOCAL, true)
 		));
 
 		context.checking(new Expectations() {{
@@ -228,18 +232,18 @@ public class TransportPropertyManagerImplTest extends BrambleMockTestCase {
 		Metadata meta = new Metadata();
 		// Version 4 is being delivered
 		BdfDictionary metaDictionary = BdfDictionary.of(
-				new BdfEntry("transportId", "foo"),
-				new BdfEntry("version", 4),
-				new BdfEntry("local", false)
+				new BdfEntry(MSG_KEY_TRANSPORT_ID, "foo"),
+				new BdfEntry(MSG_KEY_VERSION, 4),
+				new BdfEntry(MSG_KEY_LOCAL, false)
 		);
 		Map<MessageId, BdfDictionary> messageMetadata =
 				new LinkedHashMap<>();
 		// An older remote update for the same transport should be deleted
 		MessageId fooVersion3 = new MessageId(getRandomId());
 		messageMetadata.put(fooVersion3, BdfDictionary.of(
-				new BdfEntry("transportId", "foo"),
-				new BdfEntry("version", 3),
-				new BdfEntry("local", false)
+				new BdfEntry(MSG_KEY_TRANSPORT_ID, "foo"),
+				new BdfEntry(MSG_KEY_VERSION, 3),
+				new BdfEntry(MSG_KEY_LOCAL, false)
 		));
 
 		context.checking(new Expectations() {{
@@ -265,18 +269,18 @@ public class TransportPropertyManagerImplTest extends BrambleMockTestCase {
 		Metadata meta = new Metadata();
 		// Version 3 is being delivered
 		BdfDictionary metaDictionary = BdfDictionary.of(
-				new BdfEntry("transportId", "foo"),
-				new BdfEntry("version", 3),
-				new BdfEntry("local", false)
+				new BdfEntry(MSG_KEY_TRANSPORT_ID, "foo"),
+				new BdfEntry(MSG_KEY_VERSION, 3),
+				new BdfEntry(MSG_KEY_LOCAL, false)
 		);
 		Map<MessageId, BdfDictionary> messageMetadata =
 				new LinkedHashMap<>();
 		// A newer remote update for the same transport should not be deleted
 		MessageId fooVersion4 = new MessageId(getRandomId());
 		messageMetadata.put(fooVersion4, BdfDictionary.of(
-				new BdfEntry("transportId", "foo"),
-				new BdfEntry("version", 4),
-				new BdfEntry("local", false)
+				new BdfEntry(MSG_KEY_TRANSPORT_ID, "foo"),
+				new BdfEntry(MSG_KEY_VERSION, 4),
+				new BdfEntry(MSG_KEY_LOCAL, false)
 		));
 
 		context.checking(new Expectations() {{
@@ -342,9 +346,9 @@ public class TransportPropertyManagerImplTest extends BrambleMockTestCase {
 		// A local update for another transport should be ignored
 		MessageId barUpdateId = new MessageId(getRandomId());
 		messageMetadata.put(barUpdateId, BdfDictionary.of(
-				new BdfEntry("transportId", "bar"),
-				new BdfEntry("version", 1),
-				new BdfEntry("local", true)
+				new BdfEntry(MSG_KEY_TRANSPORT_ID, "bar"),
+				new BdfEntry(MSG_KEY_VERSION, 1),
+				new BdfEntry(MSG_KEY_LOCAL, true)
 		));
 
 		context.checking(new DbExpectations() {{
@@ -366,16 +370,16 @@ public class TransportPropertyManagerImplTest extends BrambleMockTestCase {
 		// A local update for another transport should be ignored
 		MessageId barUpdateId = new MessageId(getRandomId());
 		messageMetadata.put(barUpdateId, BdfDictionary.of(
-				new BdfEntry("transportId", "bar"),
-				new BdfEntry("version", 1),
-				new BdfEntry("local", true)
+				new BdfEntry(MSG_KEY_TRANSPORT_ID, "bar"),
+				new BdfEntry(MSG_KEY_VERSION, 1),
+				new BdfEntry(MSG_KEY_LOCAL, true)
 		));
 		// A local update for the right transport should be returned
 		MessageId fooUpdateId = new MessageId(getRandomId());
 		messageMetadata.put(fooUpdateId, BdfDictionary.of(
-				new BdfEntry("transportId", "foo"),
-				new BdfEntry("version", 1),
-				new BdfEntry("local", true)
+				new BdfEntry(MSG_KEY_TRANSPORT_ID, "foo"),
+				new BdfEntry(MSG_KEY_VERSION, 1),
+				new BdfEntry(MSG_KEY_LOCAL, true)
 		));
 		BdfList fooUpdate = BdfList.of("foo", 1, fooPropertiesDict);
 
@@ -405,28 +409,28 @@ public class TransportPropertyManagerImplTest extends BrambleMockTestCase {
 		List<Contact> contacts = asList(contact1, contact2);
 		Group contactGroup1 = getGroup(CLIENT_ID, MAJOR_VERSION);
 		Group contactGroup2 = getGroup(CLIENT_ID, MAJOR_VERSION);
-		Map<MessageId, BdfDictionary> messageMetadata2 =
+		Map<MessageId, BdfDictionary> messageMetadata =
 				new LinkedHashMap<>();
 		// A remote update for another transport should be ignored
 		MessageId barUpdateId = new MessageId(getRandomId());
-		messageMetadata2.put(barUpdateId, BdfDictionary.of(
-				new BdfEntry("transportId", "bar"),
-				new BdfEntry("version", 1),
-				new BdfEntry("local", false)
+		messageMetadata.put(barUpdateId, BdfDictionary.of(
+				new BdfEntry(MSG_KEY_TRANSPORT_ID, "bar"),
+				new BdfEntry(MSG_KEY_VERSION, 1),
+				new BdfEntry(MSG_KEY_LOCAL, false)
 		));
 		// A local update for the right transport should be ignored
 		MessageId localUpdateId = new MessageId(getRandomId());
-		messageMetadata2.put(localUpdateId, BdfDictionary.of(
-				new BdfEntry("transportId", "foo"),
-				new BdfEntry("version", 1),
-				new BdfEntry("local", true)
+		messageMetadata.put(localUpdateId, BdfDictionary.of(
+				new BdfEntry(MSG_KEY_TRANSPORT_ID, "foo"),
+				new BdfEntry(MSG_KEY_VERSION, 1),
+				new BdfEntry(MSG_KEY_LOCAL, true)
 		));
 		// A remote update for the right transport should be returned
 		MessageId fooUpdateId = new MessageId(getRandomId());
-		messageMetadata2.put(fooUpdateId, BdfDictionary.of(
-				new BdfEntry("transportId", "foo"),
-				new BdfEntry("version", 1),
-				new BdfEntry("local", false)
+		messageMetadata.put(fooUpdateId, BdfDictionary.of(
+				new BdfEntry(MSG_KEY_TRANSPORT_ID, "foo"),
+				new BdfEntry(MSG_KEY_VERSION, 1),
+				new BdfEntry(MSG_KEY_LOCAL, false)
 		));
 		BdfList fooUpdate = BdfList.of("foo", 1, fooPropertiesDict);
 
@@ -440,19 +444,25 @@ public class TransportPropertyManagerImplTest extends BrambleMockTestCase {
 			will(returnValue(contactGroup1));
 			oneOf(clientHelper).getMessageMetadataAsDictionary(txn,
 					contactGroup1.getId());
-			will(returnValue(Collections.emptyMap()));
+			will(returnValue(emptyMap()));
+			oneOf(clientHelper).getGroupMetadataAsDictionary(txn,
+					contactGroup1.getId());
+			will(returnValue(new BdfDictionary()));
 			// Second contact: returns an update
 			oneOf(contactGroupFactory).createContactGroup(CLIENT_ID,
 					MAJOR_VERSION, contact2);
 			will(returnValue(contactGroup2));
 			oneOf(clientHelper).getMessageMetadataAsDictionary(txn,
 					contactGroup2.getId());
-			will(returnValue(messageMetadata2));
+			will(returnValue(messageMetadata));
 			oneOf(clientHelper).getMessageAsList(txn, fooUpdateId);
 			will(returnValue(fooUpdate));
 			oneOf(clientHelper).parseAndValidateTransportProperties(
 					fooPropertiesDict);
 			will(returnValue(fooProperties));
+			oneOf(clientHelper).getGroupMetadataAsDictionary(txn,
+					contactGroup2.getId());
+			will(returnValue(new BdfDictionary()));
 		}});
 
 		TransportPropertyManagerImpl t = createInstance();
@@ -463,6 +473,62 @@ public class TransportPropertyManagerImplTest extends BrambleMockTestCase {
 		assertEquals(fooProperties, properties.get(contact2.getId()));
 	}
 
+	@Test
+	public void testReceivePropertiesOverrideDiscoveredProperties()
+			throws Exception {
+		Transaction txn = new Transaction(null, true);
+		Contact contact = getContact();
+		List<Contact> contacts = singletonList(contact);
+		Group contactGroup = getGroup(CLIENT_ID, MAJOR_VERSION);
+		MessageId updateId = new MessageId(getRandomId());
+		Map<MessageId, BdfDictionary> messageMetadata = singletonMap(updateId,
+				BdfDictionary.of(
+						new BdfEntry(MSG_KEY_TRANSPORT_ID, "foo"),
+						new BdfEntry(MSG_KEY_VERSION, 1),
+						new BdfEntry(MSG_KEY_LOCAL, false)
+				));
+		BdfList update = BdfList.of("foo", 1, fooPropertiesDict);
+		TransportProperties discovered = new TransportProperties();
+		discovered.put("fooKey1", "overridden");
+		discovered.put("fooKey3", "fooValue3");
+		BdfDictionary discoveredDict = new BdfDictionary(discovered);
+		BdfDictionary groupMeta = BdfDictionary.of(
+				new BdfEntry(GROUP_KEY_DISCOVERED, discoveredDict)
+		);
+		TransportProperties merged = new TransportProperties();
+		merged.putAll(fooProperties);
+		merged.put("fooKey3", "fooValue3");
+
+		context.checking(new DbExpectations() {{
+			oneOf(db).transactionWithResult(with(true), withDbCallable(txn));
+			oneOf(db).getContacts(txn);
+			will(returnValue(contacts));
+			// One update
+			oneOf(contactGroupFactory).createContactGroup(CLIENT_ID,
+					MAJOR_VERSION, contact);
+			will(returnValue(contactGroup));
+			oneOf(clientHelper).getMessageMetadataAsDictionary(txn,
+					contactGroup.getId());
+			will(returnValue(messageMetadata));
+			oneOf(clientHelper).getMessageAsList(txn, updateId);
+			will(returnValue(update));
+			oneOf(clientHelper).parseAndValidateTransportProperties(
+					fooPropertiesDict);
+			will(returnValue(fooProperties));
+			oneOf(clientHelper).getGroupMetadataAsDictionary(txn,
+					contactGroup.getId());
+			will(returnValue(groupMeta));
+			oneOf(clientHelper).parseAndValidateTransportProperties(
+					discoveredDict);
+			will(returnValue(discovered));
+		}});
+
+		TransportPropertyManagerImpl t = createInstance();
+		Map<ContactId, TransportProperties> properties =
+				t.getRemoteProperties(new TransportId("foo"));
+		assertEquals(merged, properties.get(contact.getId()));
+	}
+
 	@Test
 	public void testMergingUnchangedPropertiesDoesNotCreateUpdate()
 			throws Exception {
@@ -470,9 +536,9 @@ public class TransportPropertyManagerImplTest extends BrambleMockTestCase {
 		MessageId updateId = new MessageId(getRandomId());
 		Map<MessageId, BdfDictionary> messageMetadata = singletonMap(updateId,
 				BdfDictionary.of(
-						new BdfEntry("transportId", "foo"),
-						new BdfEntry("version", 1),
-						new BdfEntry("local", true)
+						new BdfEntry(MSG_KEY_TRANSPORT_ID, "foo"),
+						new BdfEntry(MSG_KEY_VERSION, 1),
+						new BdfEntry(MSG_KEY_LOCAL, true)
 				));
 		BdfList update = BdfList.of("foo", 1, fooPropertiesDict);
 
@@ -505,7 +571,7 @@ public class TransportPropertyManagerImplTest extends BrambleMockTestCase {
 			// There are no existing properties to merge with
 			oneOf(clientHelper).getMessageMetadataAsDictionary(txn,
 					localGroup.getId());
-			will(returnValue(Collections.emptyMap()));
+			will(returnValue(emptyMap()));
 			// Store the new properties in the local group, version 1
 			expectStoreMessage(txn, localGroup.getId(), "foo",
 					fooPropertiesDict, 1, true, false);
@@ -517,7 +583,7 @@ public class TransportPropertyManagerImplTest extends BrambleMockTestCase {
 			will(returnValue(contactGroup));
 			oneOf(clientHelper).getMessageMetadataAsDictionary(txn,
 					contactGroup.getId());
-			will(returnValue(Collections.emptyMap()));
+			will(returnValue(emptyMap()));
 			expectStoreMessage(txn, contactGroup.getId(), "foo",
 					fooPropertiesDict, 1, true, true);
 		}});
@@ -532,9 +598,9 @@ public class TransportPropertyManagerImplTest extends BrambleMockTestCase {
 		Contact contact = getContact();
 		Group contactGroup = getGroup(CLIENT_ID, MAJOR_VERSION);
 		BdfDictionary oldMetadata = BdfDictionary.of(
-				new BdfEntry("transportId", "foo"),
-				new BdfEntry("version", 1),
-				new BdfEntry("local", true)
+				new BdfEntry(MSG_KEY_TRANSPORT_ID, "foo"),
+				new BdfEntry(MSG_KEY_VERSION, 1),
+				new BdfEntry(MSG_KEY_LOCAL, true)
 		);
 		MessageId localGroupUpdateId = new MessageId(getRandomId());
 		Map<MessageId, BdfDictionary> localGroupMessageMetadata =
@@ -589,14 +655,14 @@ public class TransportPropertyManagerImplTest extends BrambleMockTestCase {
 		// The latest update for transport "foo" should be returned
 		MessageId fooVersion999 = new MessageId(getRandomId());
 		messageMetadata.put(fooVersion999, BdfDictionary.of(
-				new BdfEntry("transportId", "foo"),
-				new BdfEntry("version", 999)
+				new BdfEntry(MSG_KEY_TRANSPORT_ID, "foo"),
+				new BdfEntry(MSG_KEY_VERSION, 999)
 		));
 		// The latest update for transport "bar" should be returned
 		MessageId barVersion3 = new MessageId(getRandomId());
 		messageMetadata.put(barVersion3, BdfDictionary.of(
-				new BdfEntry("transportId", "bar"),
-				new BdfEntry("version", 3)
+				new BdfEntry(MSG_KEY_TRANSPORT_ID, "bar"),
+				new BdfEntry(MSG_KEY_VERSION, 3)
 		));
 		BdfList fooUpdate = BdfList.of("foo", 999, fooPropertiesDict);
 		BdfList barUpdate = BdfList.of("bar", 3, barPropertiesDict);
@@ -627,9 +693,9 @@ public class TransportPropertyManagerImplTest extends BrambleMockTestCase {
 		Message message = getMessage(g);
 		long timestamp = message.getTimestamp();
 		BdfDictionary meta = BdfDictionary.of(
-				new BdfEntry("transportId", transportId),
-				new BdfEntry("version", version),
-				new BdfEntry("local", local)
+				new BdfEntry(MSG_KEY_TRANSPORT_ID, transportId),
+				new BdfEntry(MSG_KEY_VERSION, version),
+				new BdfEntry(MSG_KEY_LOCAL, local)
 		);
 
 		context.checking(new Expectations() {{

bramble-core/src/test/java/org/briarproject/bramble/rendezvous/RendezvousPollerImplTest.java

@@ -17,8 +17,8 @@ import org.briarproject.bramble.api.plugin.ConnectionManager;
 import org.briarproject.bramble.api.plugin.PluginManager;
 import org.briarproject.bramble.api.plugin.TransportId;
 import org.briarproject.bramble.api.plugin.duplex.DuplexPlugin;
-import org.briarproject.bramble.api.plugin.event.TransportActiveEvent;
-import org.briarproject.bramble.api.plugin.event.TransportInactiveEvent;
+import org.briarproject.bramble.api.plugin.event.TransportDisabledEvent;
+import org.briarproject.bramble.api.plugin.event.TransportEnabledEvent;
 import org.briarproject.bramble.api.properties.TransportProperties;
 import org.briarproject.bramble.api.rendezvous.KeyMaterialSource;
 import org.briarproject.bramble.api.rendezvous.RendezvousEndpoint;
@@ -178,10 +178,10 @@ public class RendezvousPollerImplTest extends BrambleMockTestCase {
 		rendezvousPoller.startService();
 		context.assertIsSatisfied();
 
-		// Activate the transport - no endpoints should be created yet
+		// Enable the transport - no endpoints should be created yet
 		expectGetPlugin();
 
-		rendezvousPoller.eventOccurred(new TransportActiveEvent(transportId));
+		rendezvousPoller.eventOccurred(new TransportEnabledEvent(transportId));
 		context.assertIsSatisfied();
 
 		// Add the pending contact - endpoint should be created and polled
@@ -212,8 +212,8 @@ public class RendezvousPollerImplTest extends BrambleMockTestCase {
 				new PendingContactRemovedEvent(pendingContact.getId()));
 		context.assertIsSatisfied();
 
-		// Deactivate the transport - endpoint is already closed
-		rendezvousPoller.eventOccurred(new TransportInactiveEvent(transportId));
+		// Disable the transport - endpoint is already closed
+		rendezvousPoller.eventOccurred(new TransportDisabledEvent(transportId));
 	}
 
 	@Test
@@ -230,10 +230,10 @@ public class RendezvousPollerImplTest extends BrambleMockTestCase {
 		rendezvousPoller.startService();
 		context.assertIsSatisfied();
 
-		// Activate the transport - no endpoints should be created yet
+		// Enable the transport - no endpoints should be created yet
 		expectGetPlugin();
 
-		rendezvousPoller.eventOccurred(new TransportActiveEvent(transportId));
+		rendezvousPoller.eventOccurred(new TransportEnabledEvent(transportId));
 		context.assertIsSatisfied();
 
 		// Add the pending contact - endpoint should be created and polled
@@ -269,12 +269,12 @@ public class RendezvousPollerImplTest extends BrambleMockTestCase {
 				new PendingContactRemovedEvent(pendingContact.getId()));
 		context.assertIsSatisfied();
 
-		// Deactivate the transport - endpoint is already closed
-		rendezvousPoller.eventOccurred(new TransportInactiveEvent(transportId));
+		// Disable the transport - endpoint is already closed
+		rendezvousPoller.eventOccurred(new TransportDisabledEvent(transportId));
 	}
 
 	@Test
-	public void testCreatesAndClosesEndpointsWhenTransportIsActivatedAndDeactivated()
+	public void testCreatesAndClosesEndpointsWhenTransportIsEnabledAndDisabled()
 			throws Exception {
 		long beforeExpiry = pendingContact.getTimestamp();
 
@@ -292,19 +292,19 @@ public class RendezvousPollerImplTest extends BrambleMockTestCase {
 				new PendingContactAddedEvent(pendingContact));
 		context.assertIsSatisfied();
 
-		// Activate the transport - endpoint should be created
+		// Enable the transport - endpoint should be created
 		expectGetPlugin();
 		expectCreateEndpoint();
 		expectStateChangedEvent(WAITING_FOR_CONNECTION);
 
-		rendezvousPoller.eventOccurred(new TransportActiveEvent(transportId));
+		rendezvousPoller.eventOccurred(new TransportEnabledEvent(transportId));
 		context.assertIsSatisfied();
 
-		// Deactivate the transport - endpoint should be closed
+		// Disable the transport - endpoint should be closed
 		expectCloseEndpoint();
 		expectStateChangedEvent(OFFLINE);
 
-		rendezvousPoller.eventOccurred(new TransportInactiveEvent(transportId));
+		rendezvousPoller.eventOccurred(new TransportDisabledEvent(transportId));
 		context.assertIsSatisfied();
 
 		// Remove the pending contact - endpoint is already closed

bramble-core/src/test/java/org/briarproject/bramble/sync/SimplexOutgoingSessionTest.java

@@ -4,6 +4,7 @@ import org.briarproject.bramble.api.contact.ContactId;
 import org.briarproject.bramble.api.db.DatabaseComponent;
 import org.briarproject.bramble.api.db.Transaction;
 import org.briarproject.bramble.api.event.EventBus;
+import org.briarproject.bramble.api.plugin.TransportId;
 import org.briarproject.bramble.api.sync.Ack;
 import org.briarproject.bramble.api.sync.GroupId;
 import org.briarproject.bramble.api.sync.Message;
@@ -23,6 +24,7 @@ import static org.briarproject.bramble.api.sync.SyncConstants.MAX_MESSAGE_IDS;
 import static org.briarproject.bramble.test.TestUtils.getContactId;
 import static org.briarproject.bramble.test.TestUtils.getMessage;
 import static org.briarproject.bramble.test.TestUtils.getRandomId;
+import static org.briarproject.bramble.test.TestUtils.getTransportId;
 
 public class SimplexOutgoingSessionTest extends BrambleMockTestCase {
 
@@ -36,14 +38,15 @@ public class SimplexOutgoingSessionTest extends BrambleMockTestCase {
 
 	private final Executor dbExecutor = new ImmediateExecutor();
 	private final ContactId contactId = getContactId();
+	private final TransportId transportId = getTransportId();
 	private final Message message = getMessage(new GroupId(getRandomId()));
 	private final MessageId messageId = message.getId();
 
 	@Test
 	public void testNothingToSend() throws Exception {
 		SimplexOutgoingSession session = new SimplexOutgoingSession(db,
-				dbExecutor, eventBus, contactId, MAX_LATENCY, streamWriter,
-				recordWriter);
+				dbExecutor, eventBus, contactId, transportId, MAX_LATENCY,
+				streamWriter, recordWriter);
 		Transaction noAckTxn = new Transaction(null, false);
 		Transaction noMsgTxn = new Transaction(null, false);
 
@@ -76,8 +79,8 @@ public class SimplexOutgoingSessionTest extends BrambleMockTestCase {
 	public void testSomethingToSend() throws Exception {
 		Ack ack = new Ack(singletonList(messageId));
 		SimplexOutgoingSession session = new SimplexOutgoingSession(db,
-				dbExecutor, eventBus, contactId, MAX_LATENCY, streamWriter,
-				recordWriter);
+				dbExecutor, eventBus, contactId, transportId, MAX_LATENCY,
+				streamWriter, recordWriter);
 		Transaction ackTxn = new Transaction(null, false);
 		Transaction noAckTxn = new Transaction(null, false);
 		Transaction msgTxn = new Transaction(null, false);

bramble-core/src/test/java/org/briarproject/bramble/test/TestDuplexTransportConnection.java

@@ -4,6 +4,7 @@ import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
 import org.briarproject.bramble.api.plugin.TransportConnectionReader;
 import org.briarproject.bramble.api.plugin.TransportConnectionWriter;
 import org.briarproject.bramble.api.plugin.duplex.DuplexTransportConnection;
+import org.briarproject.bramble.api.properties.TransportProperties;
 
 import java.io.IOException;
 import java.io.InputStream;
@@ -37,6 +38,11 @@ public class TestDuplexTransportConnection
 		return writer;
 	}
 
+	@Override
+	public TransportProperties getRemoteProperties() {
+		return new TransportProperties();
+	}
+
 	/**
 	 * Creates and returns a pair of TestDuplexTransportConnections that are
 	 * connected to each other.

bramble-java/build.gradle

@@ -16,7 +16,7 @@ dependencies {
 	implementation fileTree(dir: 'libs', include: '*.jar')
 	implementation 'net.java.dev.jna:jna:4.5.2'
 	implementation 'net.java.dev.jna:jna-platform:4.5.2'
-	tor 'org.briarproject:tor:0.3.5.9@zip'
+	tor 'org.briarproject:tor:0.3.5.10@zip'
 	tor 'org.briarproject:obfs4proxy:0.0.7@zip'
 
 	annotationProcessor 'com.google.dagger:dagger-compiler:2.24'

bramble-java/src/main/java/org/briarproject/bramble/plugin/DesktopPluginModule.java

@@ -1,6 +1,7 @@
 package org.briarproject.bramble.plugin;
 
 import org.briarproject.bramble.api.event.EventBus;
+import org.briarproject.bramble.api.io.TimeoutMonitor;
 import org.briarproject.bramble.api.lifecycle.IoExecutor;
 import org.briarproject.bramble.api.lifecycle.ShutdownManager;
 import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
@@ -9,6 +10,7 @@ import org.briarproject.bramble.api.plugin.PluginConfig;
 import org.briarproject.bramble.api.plugin.duplex.DuplexPluginFactory;
 import org.briarproject.bramble.api.plugin.simplex.SimplexPluginFactory;
 import org.briarproject.bramble.api.reliability.ReliabilityLayerFactory;
+import org.briarproject.bramble.api.system.Clock;
 import org.briarproject.bramble.plugin.bluetooth.JavaBluetoothPluginFactory;
 import org.briarproject.bramble.plugin.modem.ModemPluginFactory;
 import org.briarproject.bramble.plugin.tcp.LanTcpPluginFactory;
@@ -31,15 +33,16 @@ public class DesktopPluginModule extends PluginModule {
 	PluginConfig getPluginConfig(@IoExecutor Executor ioExecutor,
 			SecureRandom random, BackoffFactory backoffFactory,
 			ReliabilityLayerFactory reliabilityFactory,
-			ShutdownManager shutdownManager, EventBus eventBus) {
-		DuplexPluginFactory bluetooth =
-				new JavaBluetoothPluginFactory(ioExecutor, random, eventBus,
-						backoffFactory);
+			ShutdownManager shutdownManager, EventBus eventBus, Clock clock,
+			TimeoutMonitor timeoutMonitor) {
+		DuplexPluginFactory bluetooth = new JavaBluetoothPluginFactory(
+				ioExecutor, random, eventBus, clock, timeoutMonitor,
+				backoffFactory);
 		DuplexPluginFactory modem = new ModemPluginFactory(ioExecutor,
 				reliabilityFactory);
-		DuplexPluginFactory lan = new LanTcpPluginFactory(ioExecutor, eventBus,
+		DuplexPluginFactory lan = new LanTcpPluginFactory(ioExecutor,
 				backoffFactory);
-		DuplexPluginFactory wan = new WanTcpPluginFactory(ioExecutor, eventBus,
+		DuplexPluginFactory wan = new WanTcpPluginFactory(ioExecutor,
 				backoffFactory, shutdownManager);
 		Collection<DuplexPluginFactory> duplex =
 				asList(bluetooth, modem, lan, wan);

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

@@ -1,5 +1,6 @@
 package org.briarproject.bramble.plugin.bluetooth;
 
+import org.briarproject.bramble.api.io.TimeoutMonitor;
 import org.briarproject.bramble.api.nullsafety.MethodsNotNullByDefault;
 import org.briarproject.bramble.api.nullsafety.ParametersNotNullByDefault;
 import org.briarproject.bramble.api.plugin.Backoff;
@@ -34,10 +35,11 @@ class JavaBluetoothPlugin extends BluetoothPlugin<StreamConnectionNotifier> {
 	private volatile LocalDevice localDevice = null;
 
 	JavaBluetoothPlugin(BluetoothConnectionLimiter connectionManager,
-			Executor ioExecutor, SecureRandom secureRandom,
-			Backoff backoff, PluginCallback callback, int maxLatency) {
-		super(connectionManager, ioExecutor, secureRandom, backoff, callback,
-				maxLatency);
+			TimeoutMonitor timeoutMonitor, Executor ioExecutor,
+			SecureRandom secureRandom, Backoff backoff,
+			PluginCallback callback, int maxLatency, int maxIdleTime) {
+		super(connectionManager, timeoutMonitor, ioExecutor, secureRandom,
+				backoff, callback, maxLatency, maxIdleTime);
 	}
 
 	@Override
@@ -119,7 +121,9 @@ class JavaBluetoothPlugin extends BluetoothPlugin<StreamConnectionNotifier> {
 		return "btspp://" + address + ":" + uuid + ";name=RFCOMM";
 	}
 
-	private DuplexTransportConnection wrapSocket(StreamConnection s) {
-		return new JavaBluetoothTransportConnection(this, connectionLimiter, s);
+	private DuplexTransportConnection wrapSocket(StreamConnection s)
+			throws IOException {
+		return new JavaBluetoothTransportConnection(this, connectionLimiter,
+				timeoutMonitor, s);
 	}
 }

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

@@ -1,6 +1,7 @@
 package org.briarproject.bramble.plugin.bluetooth;
 
 import org.briarproject.bramble.api.event.EventBus;
+import org.briarproject.bramble.api.io.TimeoutMonitor;
 import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
 import org.briarproject.bramble.api.plugin.Backoff;
 import org.briarproject.bramble.api.plugin.BackoffFactory;
@@ -8,6 +9,7 @@ import org.briarproject.bramble.api.plugin.PluginCallback;
 import org.briarproject.bramble.api.plugin.TransportId;
 import org.briarproject.bramble.api.plugin.duplex.DuplexPlugin;
 import org.briarproject.bramble.api.plugin.duplex.DuplexPluginFactory;
+import org.briarproject.bramble.api.system.Clock;
 
 import java.security.SecureRandom;
 import java.util.concurrent.Executor;
@@ -21,22 +23,27 @@ import static org.briarproject.bramble.api.plugin.BluetoothConstants.ID;
 public class JavaBluetoothPluginFactory implements DuplexPluginFactory {
 
 	private static final int MAX_LATENCY = 30 * 1000; // 30 seconds
+	private static final int MAX_IDLE_TIME = 30 * 1000; // 30 seconds
 	private static final int MIN_POLLING_INTERVAL = 60 * 1000; // 1 minute
 	private static final int MAX_POLLING_INTERVAL = 10 * 60 * 1000; // 10 mins
 	private static final double BACKOFF_BASE = 1.2;
 
 	private final Executor ioExecutor;
 	private final SecureRandom secureRandom;
-	private final BackoffFactory backoffFactory;
 	private final EventBus eventBus;
+	private final Clock clock;
+	private final TimeoutMonitor timeoutMonitor;
+	private final BackoffFactory backoffFactory;
 
 	public JavaBluetoothPluginFactory(Executor ioExecutor,
-			SecureRandom secureRandom, EventBus eventBus,
-			BackoffFactory backoffFactory) {
+			SecureRandom secureRandom, EventBus eventBus, Clock clock,
+			TimeoutMonitor timeoutMonitor, BackoffFactory backoffFactory) {
 		this.ioExecutor = ioExecutor;
 		this.secureRandom = secureRandom;
-		this.backoffFactory = backoffFactory;
 		this.eventBus = eventBus;
+		this.clock = clock;
+		this.timeoutMonitor = timeoutMonitor;
+		this.backoffFactory = backoffFactory;
 	}
 
 	@Override
@@ -52,11 +59,12 @@ public class JavaBluetoothPluginFactory implements DuplexPluginFactory {
 	@Override
 	public DuplexPlugin createPlugin(PluginCallback callback) {
 		BluetoothConnectionLimiter connectionLimiter =
-				new BluetoothConnectionLimiterImpl();
+				new BluetoothConnectionLimiterImpl(eventBus, clock);
 		Backoff backoff = backoffFactory.createBackoff(MIN_POLLING_INTERVAL,
 				MAX_POLLING_INTERVAL, BACKOFF_BASE);
 		JavaBluetoothPlugin plugin = new JavaBluetoothPlugin(connectionLimiter,
-				ioExecutor, secureRandom, backoff, callback, MAX_LATENCY);
+				timeoutMonitor, ioExecutor, secureRandom, backoff, callback,
+				MAX_LATENCY, MAX_IDLE_TIME);
 		eventBus.addListener(plugin);
 		return plugin;
 	}

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

@@ -1,5 +1,6 @@
 package org.briarproject.bramble.plugin.bluetooth;
 
+import org.briarproject.bramble.api.io.TimeoutMonitor;
 import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
 import org.briarproject.bramble.api.plugin.Plugin;
 import org.briarproject.bramble.api.plugin.duplex.AbstractDuplexTransportConnection;
@@ -14,20 +15,24 @@ import javax.microedition.io.StreamConnection;
 class JavaBluetoothTransportConnection
 		extends AbstractDuplexTransportConnection {
 
-	private final BluetoothConnectionLimiter connectionManager;
+	private final BluetoothConnectionLimiter connectionLimiter;
 	private final StreamConnection stream;
+	private final InputStream in;
 
 	JavaBluetoothTransportConnection(Plugin plugin,
-			BluetoothConnectionLimiter connectionManager,
-			StreamConnection stream) {
+			BluetoothConnectionLimiter connectionLimiter,
+			TimeoutMonitor timeoutMonitor,
+			StreamConnection stream) throws IOException {
 		super(plugin);
+		this.connectionLimiter = connectionLimiter;
 		this.stream = stream;
-		this.connectionManager = connectionManager;
+		in = timeoutMonitor.createTimeoutInputStream(
+				stream.openInputStream(), plugin.getMaxIdleTime() * 2);
 	}
 
 	@Override
-	protected InputStream getInputStream() throws IOException {
-		return stream.openInputStream();
+	protected InputStream getInputStream() {
+		return in;
 	}
 
 	@Override
@@ -40,7 +45,7 @@ class JavaBluetoothTransportConnection
 		try {
 			stream.close();
 		} finally {
-			connectionManager.connectionClosed(this);
+			connectionLimiter.connectionClosed(this, exception);
 		}
 	}
 }

bramble-java/src/main/java/org/briarproject/bramble/plugin/modem/ModemPlugin.java

@@ -4,7 +4,6 @@ import org.briarproject.bramble.api.Pair;
 import org.briarproject.bramble.api.data.BdfList;
 import org.briarproject.bramble.api.keyagreement.KeyAgreementListener;
 import org.briarproject.bramble.api.nullsafety.MethodsNotNullByDefault;
-import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
 import org.briarproject.bramble.api.nullsafety.ParametersNotNullByDefault;
 import org.briarproject.bramble.api.plugin.ConnectionHandler;
 import org.briarproject.bramble.api.plugin.PluginCallback;
@@ -24,16 +23,9 @@ import java.util.Collection;
 import java.util.concurrent.atomic.AtomicBoolean;
 import java.util.logging.Logger;
 
-import javax.annotation.concurrent.GuardedBy;
-import javax.annotation.concurrent.ThreadSafe;
-
 import static java.util.logging.Level.INFO;
 import static java.util.logging.Level.WARNING;
 import static java.util.logging.Logger.getLogger;
-import static org.briarproject.bramble.api.plugin.Plugin.State.ACTIVE;
-import static org.briarproject.bramble.api.plugin.Plugin.State.DISABLED;
-import static org.briarproject.bramble.api.plugin.Plugin.State.ENABLING;
-import static org.briarproject.bramble.api.plugin.Plugin.State.INACTIVE;
 import static org.briarproject.bramble.util.LogUtils.logException;
 import static org.briarproject.bramble.util.StringUtils.isNullOrEmpty;
 
@@ -52,8 +44,8 @@ class ModemPlugin implements DuplexPlugin, Modem.Callback {
 	private final PluginCallback callback;
 	private final int maxLatency;
 	private final AtomicBoolean used = new AtomicBoolean(false);
-	private final PluginState state = new PluginState();
 
+	private volatile boolean running = false;
 	private volatile Modem modem = null;
 
 	ModemPlugin(ModemFactory modemFactory, SerialPortList serialPortList,
@@ -83,7 +75,6 @@ class ModemPlugin implements DuplexPlugin, Modem.Callback {
 	@Override
 	public void start() throws PluginException {
 		if (used.getAndSet(true)) throw new IllegalStateException();
-		state.setStarted();
 		for (String portName : serialPortList.getPortNames()) {
 			if (LOG.isLoggable(INFO))
 				LOG.info("Trying to initialise modem on " + portName);
@@ -92,20 +83,18 @@ class ModemPlugin implements DuplexPlugin, Modem.Callback {
 				if (!modem.start()) continue;
 				if (LOG.isLoggable(INFO))
 					LOG.info("Initialised modem on " + portName);
-				state.setInitialised();
+				running = true;
 				return;
 			} catch (IOException e) {
 				logException(LOG, WARNING, e);
 			}
 		}
-		LOG.warning("Failed to initialised modem");
-		state.setFailed();
 		throw new PluginException();
 	}
 
 	@Override
 	public void stop() {
-		state.setStopped();
+		running = false;
 		if (modem != null) {
 			try {
 				modem.stop();
@@ -116,13 +105,8 @@ class ModemPlugin implements DuplexPlugin, Modem.Callback {
 	}
 
 	@Override
-	public State getState() {
-		return state.getState();
-	}
-
-	@Override
-	public int getReasonDisabled() {
-		return getState() == DISABLED ? REASON_STARTING_STOPPING : -1;
+	public boolean isRunning() {
+		return running;
 	}
 
 	@Override
@@ -141,8 +125,8 @@ class ModemPlugin implements DuplexPlugin, Modem.Callback {
 		throw new UnsupportedOperationException();
 	}
 
-	private void resetModem() {
-		if (getState() != ACTIVE) return;
+	private boolean resetModem() {
+		if (!running) return false;
 		for (String portName : serialPortList.getPortNames()) {
 			if (LOG.isLoggable(INFO))
 				LOG.info("Trying to initialise modem on " + portName);
@@ -151,18 +135,18 @@ class ModemPlugin implements DuplexPlugin, Modem.Callback {
 				if (!modem.start()) continue;
 				if (LOG.isLoggable(INFO))
 					LOG.info("Initialised modem on " + portName);
-				return;
+				return true;
 			} catch (IOException e) {
 				logException(LOG, WARNING, e);
 			}
 		}
-		LOG.warning("Failed to initialise modem");
-		state.setFailed();
+		running = false;
+		return false;
 	}
 
 	@Override
 	public DuplexTransportConnection createConnection(TransportProperties p) {
-		if (getState() != ACTIVE) return null;
+		if (!running) return null;
 		// Get the ISO 3166 code for the caller's country
 		String fromIso = callback.getLocalProperties().get("iso3166");
 		if (isNullOrEmpty(fromIso)) return null;
@@ -248,41 +232,4 @@ class ModemPlugin implements DuplexPlugin, Modem.Callback {
 			if (exception) resetModem();
 		}
 	}
-
-	@ThreadSafe
-	@NotNullByDefault
-	private class PluginState {
-
-		@GuardedBy("this")
-		private boolean started = false,
-				stopped = false,
-				initialised = false,
-				failed = false;
-
-		private synchronized void setStarted() {
-			started = true;
-			callback.pluginStateChanged(getState());
-		}
-
-		private synchronized void setStopped() {
-			stopped = true;
-			callback.pluginStateChanged(getState());
-		}
-
-		private synchronized void setInitialised() {
-			initialised = true;
-			callback.pluginStateChanged(getState());
-		}
-
-		private synchronized void setFailed() {
-			failed = true;
-			callback.pluginStateChanged(getState());
-		}
-
-		private State getState() {
-			if (!started || stopped) return DISABLED;
-			if (failed) return INACTIVE;
-			return initialised ? ACTIVE : ENABLING;
-		}
-	}
 }

bramble-java/src/test/java/org/briarproject/bramble/plugin/modem/ModemPluginTest.java

@@ -9,8 +9,6 @@ import org.junit.Test;
 
 import java.io.IOException;
 
-import static org.briarproject.bramble.api.plugin.Plugin.State.ACTIVE;
-import static org.briarproject.bramble.api.plugin.Plugin.State.ENABLING;
 import static org.junit.Assert.assertNotNull;
 import static org.junit.Assert.assertNull;
 
@@ -35,7 +33,6 @@ public class ModemPluginTest extends BrambleMockTestCase {
 	@Test
 	public void testModemCreation() throws Exception {
 		context.checking(new Expectations() {{
-			oneOf(callback).pluginStateChanged(ENABLING);
 			oneOf(serialPortList).getPortNames();
 			will(returnValue(new String[] {"foo", "bar", "baz"}));
 			// First call to createModem() returns false
@@ -53,7 +50,6 @@ public class ModemPluginTest extends BrambleMockTestCase {
 			will(returnValue(modem));
 			oneOf(modem).start();
 			will(returnValue(true));
-			oneOf(callback).pluginStateChanged(ACTIVE);
 		}});
 
 		plugin.start();
@@ -69,14 +65,12 @@ public class ModemPluginTest extends BrambleMockTestCase {
 
 		context.checking(new Expectations() {{
 			// start()
-			oneOf(callback).pluginStateChanged(ENABLING);
 			oneOf(serialPortList).getPortNames();
 			will(returnValue(new String[] {"foo"}));
 			oneOf(modemFactory).createModem(plugin, "foo");
 			will(returnValue(modem));
 			oneOf(modem).start();
 			will(returnValue(true));
-			oneOf(callback).pluginStateChanged(ACTIVE);
 			// createConnection()
 			oneOf(callback).getLocalProperties();
 			will(returnValue(local));
@@ -99,14 +93,12 @@ public class ModemPluginTest extends BrambleMockTestCase {
 
 		context.checking(new Expectations() {{
 			// start()
-			oneOf(callback).pluginStateChanged(ENABLING);
 			oneOf(serialPortList).getPortNames();
 			will(returnValue(new String[] {"foo"}));
 			oneOf(modemFactory).createModem(plugin, "foo");
 			will(returnValue(modem));
 			oneOf(modem).start();
 			will(returnValue(true));
-			oneOf(callback).pluginStateChanged(ACTIVE);
 			// createConnection()
 			oneOf(callback).getLocalProperties();
 			will(returnValue(local));
@@ -129,14 +121,12 @@ public class ModemPluginTest extends BrambleMockTestCase {
 
 		context.checking(new Expectations() {{
 			// start()
-			oneOf(callback).pluginStateChanged(ENABLING);
 			oneOf(serialPortList).getPortNames();
 			will(returnValue(new String[] {"foo"}));
 			oneOf(modemFactory).createModem(plugin, "foo");
 			will(returnValue(modem));
 			oneOf(modem).start();
 			will(returnValue(true));
-			oneOf(callback).pluginStateChanged(ACTIVE);
 			// createConnection()
 			oneOf(callback).getLocalProperties();
 			will(returnValue(local));

bramble-java/src/test/java/org/briarproject/bramble/plugin/tor/BridgeTest.java

@@ -32,7 +32,6 @@ import javax.net.SocketFactory;
 import static java.util.Collections.singletonList;
 import static java.util.concurrent.TimeUnit.SECONDS;
 import static java.util.logging.Logger.getLogger;
-import static org.briarproject.bramble.api.plugin.Plugin.State.ACTIVE;
 import static org.briarproject.bramble.test.TestUtils.deleteTestDirectory;
 import static org.briarproject.bramble.test.TestUtils.getTestDirectory;
 import static org.briarproject.bramble.test.TestUtils.isOptionalTestEnabled;
@@ -142,10 +141,10 @@ public class BridgeTest extends BrambleTestCase {
 			plugin.start();
 			long start = clock.currentTimeMillis();
 			while (clock.currentTimeMillis() - start < TIMEOUT) {
-				if (plugin.getState() == ACTIVE) return;
+				if (plugin.isRunning()) return;
 				clock.sleep(500);
 			}
-			if (plugin.getState() != ACTIVE) {
+			if (!plugin.isRunning()) {
 				fail("Could not connect to Tor within timeout.");
 			}
 		} finally {

bramble-java/src/test/java/org/briarproject/bramble/plugin/tor/TestPluginCallback.java

@@ -1,7 +1,6 @@
 package org.briarproject.bramble.plugin.tor;
 
 import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
-import org.briarproject.bramble.api.plugin.Plugin.State;
 import org.briarproject.bramble.api.plugin.PluginCallback;
 import org.briarproject.bramble.api.plugin.TransportConnectionReader;
 import org.briarproject.bramble.api.plugin.TransportConnectionWriter;
@@ -31,7 +30,11 @@ public class TestPluginCallback implements PluginCallback {
 	}
 
 	@Override
-	public void pluginStateChanged(State state) {
+	public void transportEnabled() {
+	}
+
+	@Override
+	public void transportDisabled() {
 	}
 
 	@Override

bramble-java/witness.gradle

@@ -24,7 +24,7 @@ dependencyVerification {
         'org.apache.ant:ant:1.9.4:ant-1.9.4.jar:649ae0730251de07b8913f49286d46bba7b92d47c5f332610aa426c4f02161d8',
         'org.beanshell:bsh:1.3.0:bsh-1.3.0.jar:9b04edc75d19db54f1b4e8b5355e9364384c6cf71eb0a1b9724c159d779879f8',
         'org.briarproject:obfs4proxy:0.0.7:obfs4proxy-0.0.7.zip:5b2f693262ce43a7e130f7cc7d5d1617925330640a2eb6d71085e95df8ee0642',
-        'org.briarproject:tor:0.3.5.9:tor-0.3.5.9.zip:6c3994b129db019cc23caaf50d6b4383903c40d05fbc47fc94211170a3e5d38c',
+        'org.briarproject:tor:0.3.5.10:tor-0.3.5.10.zip:7b387d3523ae8af289c23be59dc4c64ec5d3721385d7825a09705095e3318d5c',
         'org.checkerframework:checker-compat-qual:2.5.3:checker-compat-qual-2.5.3.jar:d76b9afea61c7c082908023f0cbc1427fab9abd2df915c8b8a3e7a509bccbc6d',
         'org.checkerframework:checker-qual:2.5.2:checker-qual-2.5.2.jar:64b02691c8b9d4e7700f8ee2e742dce7ea2c6e81e662b7522c9ee3bf568c040a',
         'org.codehaus.mojo:animal-sniffer-annotations:1.17:animal-sniffer-annotations-1.17.jar:92654f493ecfec52082e76354f0ebf87648dc3d5cec2e3c3cdb947c016747a53',

briar-android/artwork/transports_list_scene.xml

@@ -1,117 +0,0 @@
-<?xml version="1.0" encoding="utf-8"?>
-<MotionScene xmlns:android="http://schemas.android.com/apk/res/android"
-	xmlns:app="http://schemas.android.com/apk/res-auto">
-
-	<Transition
-		app:constraintSetEnd="@+id/end"
-		app:constraintSetStart="@id/start"
-		app:duration="1000">
-		<OnClick app:targetId="@+id/chevronView" />
-	</Transition>
-
-	<ConstraintSet android:id="@+id/start">
-		<Constraint
-			android:id="@+id/chevronView"
-			android:layout_width="0dp"
-			android:layout_height="24dp"
-			android:layout_marginBottom="8dp"
-			app:layout_constraintBottom_toTopOf="@+id/longRangeLabel"
-			app:layout_constraintEnd_toEndOf="parent"
-			app:layout_constraintStart_toStartOf="parent"
-			app:layout_constraintTop_toBottomOf="@+id/navigation"
-			app:layout_constraintVertical_bias="1.0">
-			<CustomAttribute
-				app:attributeName="crossfade"
-				app:customFloatValue="0" />
-		</Constraint>
-	</ConstraintSet>
-
-	<ConstraintSet android:id="@+id/end">
-		<Constraint
-			android:id="@+id/chevronView"
-			android:layout_width="0dp"
-			android:layout_height="24dp"
-			android:layout_marginBottom="8dp"
-			app:layout_constraintBottom_toTopOf="@+id/connectionsLabel"
-			app:layout_constraintEnd_toEndOf="parent"
-			app:layout_constraintStart_toStartOf="parent"
-			app:layout_constraintVertical_bias="1.0">
-			<CustomAttribute
-				app:attributeName="crossfade"
-				app:customFloatValue="1" />
-		</Constraint>
-		<Constraint
-			android:id="@+id/backgroundView"
-			android:layout_width="0dp"
-			android:layout_height="0dp"
-			app:layout_constraintBottom_toBottomOf="parent"
-			app:layout_constraintEnd_toEndOf="parent"
-			app:layout_constraintStart_toStartOf="parent"
-			app:layout_constraintTop_toBottomOf="@+id/chevronView" />
-		<Constraint
-			android:id="@+id/torSwitch"
-			android:visibility="gone"
-			app:layout_constraintBottom_toTopOf="@id/nearbyLabel"
-			app:layout_constraintStart_toEndOf="parent" />
-		<Constraint
-			android:id="@+id/wifiSwitch"
-			android:visibility="gone"
-			app:layout_constraintBottom_toTopOf="@+id/btSwitch"
-			app:layout_constraintStart_toEndOf="parent" />
-		<Constraint
-			android:id="@+id/btSwitch"
-			android:visibility="gone"
-			app:layout_constraintBottom_toBottomOf="parent"
-			app:layout_constraintStart_toEndOf="parent" />
-		<Constraint
-			android:id="@+id/longRangeLabel"
-			android:visibility="gone"
-			app:layout_constraintBottom_toTopOf="@+id/torSwitch"
-			app:layout_constraintStart_toEndOf="parent" />
-		<Constraint
-			android:id="@+id/nearbyLabel"
-			android:visibility="gone"
-			app:layout_constraintBottom_toTopOf="@+id/wifiSwitch"
-			app:layout_constraintStart_toEndOf="parent" />
-		<Constraint
-			android:id="@+id/torIcon"
-			android:layout_width="20dp"
-			android:layout_height="20dp"
-			android:layout_marginEnd="8dp"
-			android:layout_marginRight="8dp"
-			app:layout_constraintBottom_toBottomOf="parent"
-			app:layout_constraintEnd_toStartOf="@+id/wifiIcon"
-			app:layout_constraintTop_toBottomOf="@+id/chevronView" />
-		<Constraint
-			android:id="@+id/wifiIcon"
-			android:layout_width="20dp"
-			android:layout_height="20dp"
-			android:layout_marginEnd="8dp"
-			android:layout_marginRight="8dp"
-			app:layout_constraintBottom_toBottomOf="parent"
-			app:layout_constraintEnd_toStartOf="@+id/btIcon"
-			app:layout_constraintTop_toBottomOf="@+id/chevronView" />
-		<Constraint
-			android:id="@+id/btIcon"
-			android:layout_width="20dp"
-			android:layout_height="20dp"
-			android:layout_marginTop="8dp"
-			android:layout_marginEnd="8dp"
-			android:layout_marginRight="8dp"
-			android:layout_marginBottom="8dp"
-			app:layout_constraintBottom_toBottomOf="parent"
-			app:layout_constraintEnd_toEndOf="parent"
-			app:layout_constraintTop_toBottomOf="@+id/chevronView" />
-		<Constraint
-			android:id="@+id/connectionsLabel"
-			android:layout_marginStart="8dp"
-			android:layout_marginLeft="8dp"
-			android:layout_marginEnd="8dp"
-			android:layout_marginRight="8dp"
-			android:visibility="visible"
-			app:layout_constraintBottom_toBottomOf="@+id/torIcon"
-			app:layout_constraintEnd_toStartOf="@+id/torIcon"
-			app:layout_constraintStart_toStartOf="parent"
-			app:layout_constraintTop_toTopOf="@+id/torIcon" />
-	</ConstraintSet>
-</MotionScene>

briar-android/build.gradle

@@ -22,8 +22,8 @@ android {
 	defaultConfig {
 		minSdkVersion 16
 		targetSdkVersion 28
-		versionCode 10205
-		versionName "1.2.5"
+		versionCode 10207
+		versionName "1.2.7"
 		applicationId "org.briarproject.briar.android"
 		buildConfigField "String", "GitHash",
 				"\"${getStdout(['git', 'rev-parse', '--short=7', 'HEAD'], 'No commit hash')}\""
@@ -98,7 +98,7 @@ dependencies {
 	implementation 'androidx.lifecycle:lifecycle-extensions:2.1.0'
 	implementation 'androidx.constraintlayout:constraintlayout:1.1.3'
 	implementation 'com.google.android.material:material:1.1.0-beta01'
-	implementation 'androidx.recyclerview:recyclerview-selection:1.0.0'
+	implementation 'androidx.recyclerview:recyclerview-selection:1.1.0-rc01'
 
 	implementation 'ch.acra:acra:4.11'
 	implementation 'info.guardianproject.panic:panic:1.0'

briar-android/src/main/java/org/briarproject/briar/android/AndroidKeyStrengthener.java

@@ -28,7 +28,9 @@ import static android.security.keystore.KeyProperties.PURPOSE_SIGN;
 import static java.util.Arrays.asList;
 import static java.util.Collections.singletonList;
 import static java.util.logging.Level.INFO;
+import static java.util.logging.Level.WARNING;
 import static java.util.logging.Logger.getLogger;
+import static org.briarproject.bramble.util.LogUtils.logException;
 
 @RequiresApi(23)
 @NotNullByDefault
@@ -79,7 +81,10 @@ class AndroidKeyStrengthener implements KeyStrengthener {
 				return true;
 			}
 			return false;
-		} catch (GeneralSecurityException | IOException e) {
+		} catch (GeneralSecurityException e) {
+			logException(LOG, WARNING, e);
+			return false;
+		} catch (IOException e) {
 			throw new RuntimeException(e);
 		}
 	}

briar-android/src/main/java/org/briarproject/briar/android/AppModule.java

@@ -14,6 +14,7 @@ import org.briarproject.bramble.api.crypto.KeyStrengthener;
 import org.briarproject.bramble.api.crypto.PublicKey;
 import org.briarproject.bramble.api.db.DatabaseConfig;
 import org.briarproject.bramble.api.event.EventBus;
+import org.briarproject.bramble.api.io.TimeoutMonitor;
 import org.briarproject.bramble.api.lifecycle.IoExecutor;
 import org.briarproject.bramble.api.lifecycle.LifecycleManager;
 import org.briarproject.bramble.api.network.NetworkManager;
@@ -36,7 +37,7 @@ import org.briarproject.bramble.util.AndroidUtils;
 import org.briarproject.bramble.util.StringUtils;
 import org.briarproject.briar.android.account.LockManagerImpl;
 import org.briarproject.briar.android.keyagreement.ContactExchangeModule;
-import org.briarproject.briar.android.navdrawer.NavDrawerModule;
+import org.briarproject.briar.android.login.LoginModule;
 import org.briarproject.briar.android.viewmodel.ViewModelModule;
 import org.briarproject.briar.api.android.AndroidNotificationManager;
 import org.briarproject.briar.api.android.DozeWatchdog;
@@ -66,8 +67,8 @@ import static org.briarproject.bramble.api.reporting.ReportingConstants.DEV_PUBL
 import static org.briarproject.briar.android.TestingConstants.IS_DEBUG_BUILD;
 
 @Module(includes = {
-		NavDrawerModule.class,
 		ContactExchangeModule.class,
+		LoginModule.class,
 		ViewModelModule.class
 })
 public class AppModule {
@@ -122,11 +123,12 @@ public class AppModule {
 			LocationUtils locationUtils, EventBus eventBus,
 			ResourceProvider resourceProvider,
 			CircumventionProvider circumventionProvider,
-			BatteryManager batteryManager, Clock clock) {
+			BatteryManager batteryManager, Clock clock,
+			TimeoutMonitor timeoutMonitor) {
 		Context appContext = app.getApplicationContext();
-		DuplexPluginFactory bluetooth =
-				new AndroidBluetoothPluginFactory(ioExecutor, androidExecutor,
-						appContext, random, eventBus, clock, backoffFactory);
+		DuplexPluginFactory bluetooth = new AndroidBluetoothPluginFactory(
+				ioExecutor, androidExecutor, appContext, random, eventBus,
+				clock, timeoutMonitor, backoffFactory);
 		DuplexPluginFactory tor = new AndroidTorPluginFactory(ioExecutor,
 				scheduler, appContext, networkManager, locationUtils, eventBus,
 				torSocketFactory, backoffFactory, resourceProvider,

briar-android/src/main/java/org/briarproject/briar/android/activity/ActivityModule.java

@@ -8,8 +8,8 @@ import org.briarproject.briar.android.controller.BriarController;
 import org.briarproject.briar.android.controller.BriarControllerImpl;
 import org.briarproject.briar.android.controller.DbController;
 import org.briarproject.briar.android.controller.DbControllerImpl;
-import org.briarproject.briar.android.login.ChangePasswordController;
-import org.briarproject.briar.android.login.ChangePasswordControllerImpl;
+import org.briarproject.briar.android.navdrawer.NavDrawerController;
+import org.briarproject.briar.android.navdrawer.NavDrawerControllerImpl;
 
 import dagger.Module;
 import dagger.Provides;
@@ -44,13 +44,6 @@ public class ActivityModule {
 		return setupController;
 	}
 
-	@ActivityScope
-	@Provides
-	ChangePasswordController providePasswordController(
-			ChangePasswordControllerImpl passwordController) {
-		return passwordController;
-	}
-
 	@ActivityScope
 	@Provides
 	protected BriarController provideBriarController(
@@ -65,10 +58,17 @@ public class ActivityModule {
 		return dbController;
 	}
 
+	@ActivityScope
+	@Provides
+	NavDrawerController provideNavDrawerController(
+			NavDrawerControllerImpl navDrawerController) {
+		activity.addLifecycleController(navDrawerController);
+		return navDrawerController;
+	}
+
 	@ActivityScope
 	@Provides
 	BriarServiceConnection provideBriarServiceConnection() {
 		return new BriarServiceConnection();
 	}
-
 }

briar-android/src/main/java/org/briarproject/briar/android/activity/BaseActivity.java

@@ -92,6 +92,9 @@ public abstract class BaseActivity extends AppCompatActivity
 				.build();
 		injectActivity(activityComponent);
 		super.onCreate(state);
+		if (LOG.isLoggable(INFO)) {
+			LOG.info("Creating " + getClass().getSimpleName());
+		}
 
 		// WARNING: When removing this or making it possible to turn it off,
 		//          we need a solution for the app lock feature.
@@ -127,8 +130,9 @@ public abstract class BaseActivity extends AppCompatActivity
 	@Override
 	protected void onStart() {
 		super.onStart();
-		if (LOG.isLoggable(INFO))
-			LOG.info("Starting " + this.getClass().getSimpleName());
+		if (LOG.isLoggable(INFO)) {
+			LOG.info("Starting " + getClass().getSimpleName());
+		}
 		for (ActivityLifecycleController alc : lifecycleControllers) {
 			alc.onActivityStart();
 		}
@@ -144,11 +148,28 @@ public abstract class BaseActivity extends AppCompatActivity
 		return (ScreenFilterDialogFragment) f;
 	}
 
+	@Override
+	protected void onResume() {
+		super.onResume();
+		if (LOG.isLoggable(INFO)) {
+			LOG.info("Resuming " + getClass().getSimpleName());
+		}
+	}
+
+	@Override
+	protected void onPause() {
+		super.onPause();
+		if (LOG.isLoggable(INFO)) {
+			LOG.info("Pausing " + getClass().getSimpleName());
+		}
+	}
+
 	@Override
 	protected void onStop() {
 		super.onStop();
-		if (LOG.isLoggable(INFO))
-			LOG.info("Stopping " + this.getClass().getSimpleName());
+		if (LOG.isLoggable(INFO)) {
+			LOG.info("Stopping " + getClass().getSimpleName());
+		}
 		for (ActivityLifecycleController alc : lifecycleControllers) {
 			alc.onActivityStop();
 		}
@@ -203,6 +224,9 @@ public abstract class BaseActivity extends AppCompatActivity
 	@Override
 	protected void onDestroy() {
 		super.onDestroy();
+		if (LOG.isLoggable(INFO)) {
+			LOG.info("Destroying " + getClass().getSimpleName());
+		}
 		destroyed = true;
 		for (ActivityLifecycleController alc : lifecycleControllers) {
 			alc.onActivityDestroy();

briar-android/src/main/java/org/briarproject/briar/android/activity/BriarActivity.java

@@ -95,12 +95,14 @@ public abstract class BriarActivity extends BaseActivity {
 			// Also check that the activity isn't finishing already.
 			// This is possible if we finished in onActivityResult().
 			// Launching another StartupActivity would cause a loop.
+			LOG.info("Not signed in, launching StartupActivity");
 			Intent i = new Intent(this, StartupActivity.class);
 			startActivityForResult(i, REQUEST_PASSWORD);
 		} else if (lockManager.isLocked() && !isFinishing()) {
 			// Also check that the activity isn't finishing already.
 			// This is possible if we finished in onActivityResult().
 			// Launching another UnlockActivity would cause a loop.
+			LOG.info("Locked, launching UnlockActivity");
 			Intent i = new Intent(this, UnlockActivity.class);
 			startActivityForResult(i, REQUEST_UNLOCK);
 		} else if (SDK_INT >= 23) {

briar-android/src/main/java/org/briarproject/briar/android/blog/BlogController.java

@@ -9,7 +9,6 @@ import org.briarproject.briar.android.controller.handler.ResultExceptionHandler;
 
 import java.util.Collection;
 
-import androidx.annotation.Nullable;
 import androidx.annotation.UiThread;
 
 @NotNullByDefault
@@ -18,7 +17,10 @@ public interface BlogController extends BaseController {
 	void setGroupId(GroupId g);
 
 	@UiThread
-	void setBlogSharingListener(@Nullable BlogSharingListener listener);
+	void setBlogSharingListener(BlogSharingListener listener);
+
+	@UiThread
+	void unsetBlogSharingListener(BlogSharingListener listener);
 
 	void loadBlogPosts(
 			ResultExceptionHandler<Collection<BlogPostItem>, DbException> handler);

briar-android/src/main/java/org/briarproject/briar/android/blog/BlogControllerImpl.java

@@ -96,10 +96,15 @@ class BlogControllerImpl extends BaseControllerImpl
 	}
 
 	@Override
-	public void setBlogSharingListener(@Nullable BlogSharingListener listener) {
+	public void setBlogSharingListener(BlogSharingListener listener) {
 		this.listener = listener;
 	}
 
+	@Override
+	public void unsetBlogSharingListener(BlogSharingListener listener) {
+		if (this.listener == listener) this.listener = null;
+	}
+
 	@Override
 	public void eventOccurred(Event e) {
 		if (groupId == null || listener == null)

briar-android/src/main/java/org/briarproject/briar/android/blog/BlogFragment.java

@@ -141,7 +141,8 @@ public class BlogFragment extends BaseFragment
 	@Override
 	public void onDestroy() {
 		super.onDestroy();
-		blogController.setBlogSharingListener(null);
+		blogController.unsetBlogSharingListener(this);
+		sharingController.unsetSharingListener(this);
 	}
 
 	@Override

briar-android/src/main/java/org/briarproject/briar/android/blog/FeedController.java

@@ -7,7 +7,6 @@ import org.briarproject.briar.api.blog.Blog;
 
 import java.util.Collection;
 
-import androidx.annotation.Nullable;
 import androidx.annotation.UiThread;
 
 @NotNullByDefault
@@ -19,7 +18,10 @@ public interface FeedController extends BaseController {
 	void loadPersonalBlog(ResultExceptionHandler<Blog, DbException> handler);
 
 	@UiThread
-	void setFeedListener(@Nullable FeedListener listener);
+	void setFeedListener(FeedListener listener);
+
+	@UiThread
+	void unsetFeedListener(FeedListener listener);
 
 	@NotNullByDefault
 	interface FeedListener extends BlogListener {

briar-android/src/main/java/org/briarproject/briar/android/blog/FeedControllerImpl.java

@@ -69,10 +69,15 @@ class FeedControllerImpl extends BaseControllerImpl implements FeedController {
 	}
 
 	@Override
-	public void setFeedListener(@Nullable FeedListener listener) {
+	public void setFeedListener(FeedListener listener) {
 		this.listener = listener;
 	}
 
+	@Override
+	public void unsetFeedListener(FeedListener listener) {
+		if (this.listener == listener) this.listener = null;
+	}
+
 	@Override
 	public void eventOccurred(Event e) {
 		if (listener == null) throw new IllegalStateException();

briar-android/src/main/java/org/briarproject/briar/android/blog/FeedFragment.java

@@ -134,7 +134,7 @@ public class FeedFragment extends BaseFragment implements
 	@Override
 	public void onDestroy() {
 		super.onDestroy();
-		feedController.setFeedListener(null);
+		feedController.unsetFeedListener(this);
 	}
 
 	@Override

briar-android/src/main/java/org/briarproject/briar/android/contact/ContactListFragment.java

@@ -61,7 +61,7 @@ import io.github.kobakei.materialfabspeeddial.FabSpeedDial.OnMenuItemClickListen
 import static android.os.Build.VERSION.SDK_INT;
 import static androidx.core.app.ActivityOptionsCompat.makeSceneTransitionAnimation;
 import static androidx.core.view.ViewCompat.getTransitionName;
-import static com.google.android.material.snackbar.Snackbar.LENGTH_INDEFINITE;
+import static com.google.android.material.snackbar.BaseTransientBottomBar.LENGTH_INDEFINITE;
 import static java.util.Objects.requireNonNull;
 import static java.util.logging.Level.WARNING;
 import static org.briarproject.bramble.util.LogUtils.logDuration;
@@ -87,7 +87,12 @@ public class ContactListFragment extends BaseFragment implements EventListener,
 
 	private ContactListAdapter adapter;
 	private BriarRecyclerView list;
-	private Snackbar snackbar;
+	/**
+	 * The Snackbar is non-null when shown and null otherwise.
+	 * Use {@link #showSnackBar()} and {@link #dismissSnackBar()} to interact.
+	 */
+	@Nullable
+	private Snackbar snackbar = null;
 
 	// Fields that are accessed from background threads must be volatile
 	@Inject
@@ -163,13 +168,6 @@ public class ContactListFragment extends BaseFragment implements EventListener,
 		list.setEmptyText(getString(R.string.no_contacts));
 		list.setEmptyAction(getString(R.string.no_contacts_action));
 
-		snackbar = new BriarSnackbarBuilder()
-				.setAction(R.string.show, v ->
-						startActivity(new Intent(getContext(),
-								PendingContactListActivity.class)))
-				.make(contentView, R.string.pending_contact_requests_snackbar,
-						LENGTH_INDEFINITE);
-
 		return contentView;
 	}
 
@@ -203,9 +201,9 @@ public class ContactListFragment extends BaseFragment implements EventListener,
 		listener.runOnDbThread(() -> {
 			try {
 				if (contactManager.getPendingContacts().isEmpty()) {
-					runOnUiThreadUnlessDestroyed(() -> snackbar.dismiss());
+					runOnUiThreadUnlessDestroyed(this::dismissSnackBar);
 				} else {
-					runOnUiThreadUnlessDestroyed(() -> snackbar.show());
+					runOnUiThreadUnlessDestroyed(this::showSnackBar);
 				}
 			} catch (DbException e) {
 				logException(LOG, WARNING, e);
@@ -220,6 +218,7 @@ public class ContactListFragment extends BaseFragment implements EventListener,
 		adapter.clear();
 		list.showProgressBar();
 		list.stopPeriodicUpdate();
+		dismissSnackBar();
 	}
 
 	private void loadContacts() {
@@ -315,4 +314,27 @@ public class ContactListFragment extends BaseFragment implements EventListener,
 		}
 	}
 
+	@UiThread
+	private void showSnackBar() {
+		if (snackbar != null) return;
+		View v = requireNonNull(getView());
+		int stringRes = R.string.pending_contact_requests_snackbar;
+		snackbar = new BriarSnackbarBuilder()
+				.setAction(R.string.show, view -> showPendingContactList())
+				.make(v, stringRes, LENGTH_INDEFINITE);
+		snackbar.show();
+	}
+
+	@UiThread
+	private void dismissSnackBar() {
+		if (snackbar == null) return;
+		snackbar.dismiss();
+		snackbar = null;
+	}
+
+	private void showPendingContactList() {
+		Intent i = new Intent(getContext(), PendingContactListActivity.class);
+		startActivity(i);
+	}
+
 }

briar-android/src/main/java/org/briarproject/briar/android/contact/add/remote/PendingContactListViewModel.java

@@ -92,7 +92,7 @@ public class PendingContactListViewModel extends AndroidViewModel
 				Collection<Pair<PendingContact, PendingContactState>> pairs =
 						contactManager.getPendingContacts();
 				List<PendingContactItem> items = new ArrayList<>(pairs.size());
-				boolean online = items.isEmpty();
+				boolean online = pairs.isEmpty();
 				for (Pair<PendingContact, PendingContactState> pair : pairs) {
 					PendingContact p = pair.getFirst();
 					PendingContactState state = pair.getSecond();

briar-android/src/main/java/org/briarproject/briar/android/contact/add/remote/PendingContactViewHolder.java

@@ -54,8 +54,6 @@ class PendingContactViewHolder extends ViewHolder {
 				status.setText(R.string.waiting_for_contact_to_come_online);
 				break;
 			case OFFLINE:
-				color = ContextCompat
-						.getColor(status.getContext(), R.color.briar_yellow);
 				status.setText("");
 				break;
 			case CONNECTING:

briar-android/src/main/java/org/briarproject/briar/android/controller/SharingController.java

@@ -16,6 +16,12 @@ public interface SharingController {
 	@UiThread
 	void setSharingListener(SharingListener listener);
 
+	/**
+	 * Unsets the listener.
+	 */
+	@UiThread
+	void unsetSharingListener(SharingListener listener);
+
 	/**
 	 * Call this when your lifecycle starts,
 	 * so the listener will be called when information changes.

briar-android/src/main/java/org/briarproject/briar/android/controller/SharingControllerImpl.java

@@ -43,6 +43,11 @@ public class SharingControllerImpl implements SharingController, EventListener {
 		this.listener = listener;
 	}
 
+	@Override
+	public void unsetSharingListener(SharingListener listener) {
+		if (this.listener == listener) this.listener = null;
+	}
+
 	@Override
 	public void onStart() {
 		eventBus.addListener(this);