Don't allow multiple messages to be queued in memory for validation at startup.

Make briar-headless.jar deterministic

See merge request briar/briar!1282

.idea/codeStyles/Project.xml

@@ -1,8 +1,5 @@
 <component name="ProjectCodeStyleConfiguration">
   <code_scheme name="Project" version="173">
-    <AndroidXmlCodeStyleSettings>
-      <option name="ARRANGEMENT_SETTINGS_MIGRATED_TO_191" value="true" />
-    </AndroidXmlCodeStyleSettings>
     <JavaCodeStyleSettings>
       <option name="ANNOTATION_PARAMETER_WRAP" value="1" />
       <option name="IMPORT_LAYOUT_TABLE">

TRANSLATION.md

@@ -0,0 +1,9 @@
+Translations for this project are managed through Transifex:
+
+https://transifex.com/otf/briar
+
+If you'd like to volunteer as a translator, please create a Transifex account and request to be
+added to the project's translation team. The Localization Lab has some instructions and advice for
+translators here:
+
+https://wiki.localizationlab.org/index.php/Briar

bramble-android/build.gradle

@@ -11,8 +11,8 @@ android {
 	defaultConfig {
 		minSdkVersion 16
 		targetSdkVersion 28
-		versionCode 10207
+		versionCode 10209
-		versionName "1.2.7"
+		versionName "1.2.9"
 		consumerProguardFiles 'proguard-rules.txt'
 
 		testInstrumentationRunner "androidx.test.runner.AndroidJUnitRunner"

bramble-android/src/main/AndroidManifest.xml

@@ -16,6 +16,8 @@
 		android:label="@string/app_name"
 		android:supportsRtl="true">
 
+		<receiver android:name=".system.AlarmReceiver" />
+
 	</application>
 
 </manifest>

bramble-android/src/main/java/org/briarproject/bramble/BrambleAndroidModule.java

@@ -6,6 +6,8 @@ import org.briarproject.bramble.plugin.tor.CircumventionModule;
 import org.briarproject.bramble.reporting.ReportingModule;
 import org.briarproject.bramble.socks.SocksModule;
 import org.briarproject.bramble.system.AndroidSystemModule;
+import org.briarproject.bramble.system.AndroidTaskSchedulerModule;
+import org.briarproject.bramble.system.AndroidWakefulIoExecutorModule;
 
 import dagger.Module;
 
@@ -13,6 +15,8 @@ import dagger.Module;
 		AndroidBatteryModule.class,
 		AndroidNetworkModule.class,
 		AndroidSystemModule.class,
+		AndroidTaskSchedulerModule.class,
+		AndroidWakefulIoExecutorModule.class,
 		CircumventionModule.class,
 		ReportingModule.class,
 		SocksModule.class

bramble-android/src/main/java/org/briarproject/bramble/BrambleAppComponent.java

@@ -0,0 +1,8 @@
+package org.briarproject.bramble;
+
+import org.briarproject.bramble.api.system.AlarmListener;
+
+public interface BrambleAppComponent {
+
+	AlarmListener alarmListener();
+}

bramble-android/src/main/java/org/briarproject/bramble/BrambleApplication.java

@@ -0,0 +1,6 @@
+package org.briarproject.bramble;
+
+public interface BrambleApplication {
+
+	BrambleAppComponent getBrambleAppComponent();
+}

bramble-android/src/main/java/org/briarproject/bramble/api/system/AlarmListener.java

@@ -0,0 +1,11 @@
+package org.briarproject.bramble.api.system;
+
+import android.content.Intent;
+
+import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
+
+@NotNullByDefault
+public interface AlarmListener {
+
+	void onAlarm(Intent intent);
+}

bramble-android/src/main/java/org/briarproject/bramble/api/system/AndroidWakeLock.java

@@ -0,0 +1,19 @@
+package org.briarproject.bramble.api.system;
+
+import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
+
+@NotNullByDefault
+public interface AndroidWakeLock {
+
+	/**
+	 * Acquires the wake lock. This has no effect if the wake lock has already
+	 * been acquired.
+	 */
+	void acquire();
+
+	/**
+	 * Releases the wake lock. This has no effect if the wake lock has already
+	 * been released.
+	 */
+	void release();
+}

bramble-android/src/main/java/org/briarproject/bramble/api/system/AndroidWakeLockManager.java

@@ -0,0 +1,38 @@
+package org.briarproject.bramble.api.system;
+
+import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
+
+import java.util.concurrent.Executor;
+
+@NotNullByDefault
+public interface AndroidWakeLockManager {
+
+	/**
+	 * Creates a wake lock with the given tag. The tag is only used for
+	 * logging; the underlying OS wake lock will use its own tag.
+	 */
+	AndroidWakeLock createWakeLock(String tag);
+
+	/**
+	 * Runs the given task while holding a wake lock.
+	 */
+	void runWakefully(Runnable r, String tag);
+
+	/**
+	 * Submits the given task to the given executor while holding a wake lock.
+	 * The lock is released when the task completes, or if an exception is
+	 * thrown while submitting or running the task.
+	 */
+	void executeWakefully(Runnable r, Executor executor, String tag);
+
+	/**
+	 * Starts a dedicated thread to run the given task asynchronously. A wake
+	 * lock is acquired before starting the thread and released when the task
+	 * completes, or if an exception is thrown while starting the thread or
+	 * running the task.
+	 * <p>
+	 * This method should only be used for lifecycle management tasks that
+	 * can't be run on an executor.
+	 */
+	void executeWakefully(Runnable r, String tag);
+}

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

@@ -9,16 +9,17 @@ import android.net.ConnectivityManager;
 import android.net.NetworkInfo;
 
 import org.briarproject.bramble.api.event.EventBus;
+import org.briarproject.bramble.api.event.EventExecutor;
 import org.briarproject.bramble.api.lifecycle.Service;
 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.ParametersNotNullByDefault;
-import org.briarproject.bramble.api.system.Scheduler;
+import org.briarproject.bramble.api.system.TaskScheduler;
+import org.briarproject.bramble.api.system.TaskScheduler.Cancellable;
 
-import java.util.concurrent.Future;
+import java.util.concurrent.Executor;
-import java.util.concurrent.ScheduledExecutorService;
 import java.util.concurrent.TimeUnit;
 import java.util.concurrent.atomic.AtomicBoolean;
 import java.util.concurrent.atomic.AtomicReference;
@@ -50,20 +51,22 @@ class AndroidNetworkManager implements NetworkManager, Service {
 	private static final String WIFI_AP_STATE_CHANGED_ACTION =
 			"android.net.wifi.WIFI_AP_STATE_CHANGED";
 
-	private final ScheduledExecutorService scheduler;
+	private final TaskScheduler scheduler;
 	private final EventBus eventBus;
+	private final Executor eventExecutor;
 	private final Context appContext;
-	private final AtomicReference<Future<?>> connectivityCheck =
+	private final AtomicReference<Cancellable> connectivityCheck =
 			new AtomicReference<>();
 	private final AtomicBoolean used = new AtomicBoolean(false);
 
 	private volatile BroadcastReceiver networkStateReceiver = null;
 
 	@Inject
-	AndroidNetworkManager(@Scheduler ScheduledExecutorService scheduler,
+	AndroidNetworkManager(TaskScheduler scheduler, EventBus eventBus,
-			EventBus eventBus, Application app) {
+			@EventExecutor Executor eventExecutor, Application app) {
 		this.scheduler = scheduler;
 		this.eventBus = eventBus;
+		this.eventExecutor = eventExecutor;
 		this.appContext = app.getApplicationContext();
 	}
 
@@ -104,11 +107,12 @@ class AndroidNetworkManager implements NetworkManager, Service {
 	}
 
 	private void scheduleConnectionStatusUpdate(int delay, TimeUnit unit) {
-		Future<?> newConnectivityCheck =
+		Cancellable newConnectivityCheck =
-				scheduler.schedule(this::updateConnectionStatus, delay, unit);
+				scheduler.schedule(this::updateConnectionStatus, eventExecutor,
-		Future<?> oldConnectivityCheck =
+						delay, unit);
+		Cancellable oldConnectivityCheck =
 				connectivityCheck.getAndSet(newConnectivityCheck);
-		if (oldConnectivityCheck != null) oldConnectivityCheck.cancel(false);
+		if (oldConnectivityCheck != null) oldConnectivityCheck.cancel();
 	}
 
 	private class NetworkStateReceiver extends BroadcastReceiver {

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

@@ -0,0 +1,36 @@
+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.duplex.DuplexPlugin;
+import org.briarproject.bramble.api.plugin.duplex.DuplexTransportConnection;
+import org.briarproject.bramble.api.system.AndroidWakeLockManager;
+
+import java.io.IOException;
+
+@NotNullByDefault
+class AndroidBluetoothConnectionFactory
+		implements BluetoothConnectionFactory<BluetoothSocket> {
+
+	private final BluetoothConnectionLimiter connectionLimiter;
+	private final AndroidWakeLockManager wakeLockManager;
+	private final TimeoutMonitor timeoutMonitor;
+
+	AndroidBluetoothConnectionFactory(
+			BluetoothConnectionLimiter connectionLimiter,
+			AndroidWakeLockManager wakeLockManager,
+			TimeoutMonitor timeoutMonitor) {
+		this.connectionLimiter = connectionLimiter;
+		this.wakeLockManager = wakeLockManager;
+		this.timeoutMonitor = timeoutMonitor;
+	}
+
+	@Override
+	public DuplexTransportConnection wrapSocket(DuplexPlugin plugin,
+			BluetoothSocket s) throws IOException {
+		return new AndroidBluetoothTransportConnection(plugin,
+				connectionLimiter, wakeLockManager, timeoutMonitor, s);
+	}
+}

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

@@ -1,5 +1,6 @@
 package org.briarproject.bramble.plugin.bluetooth;
 
+import android.app.Application;
 import android.bluetooth.BluetoothAdapter;
 import android.bluetooth.BluetoothDevice;
 import android.bluetooth.BluetoothServerSocket;
@@ -9,7 +10,6 @@ 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;
@@ -59,7 +59,8 @@ import static org.briarproject.bramble.util.PrivacyUtils.scrubMacAddress;
 
 @MethodsNotNullByDefault
 @ParametersNotNullByDefault
-class AndroidBluetoothPlugin extends BluetoothPlugin<BluetoothServerSocket> {
+class AndroidBluetoothPlugin
+		extends BluetoothPlugin<BluetoothSocket, BluetoothServerSocket> {
 
 	private static final Logger LOG =
 			getLogger(AndroidBluetoothPlugin.class.getName());
@@ -67,24 +68,31 @@ class AndroidBluetoothPlugin extends BluetoothPlugin<BluetoothServerSocket> {
 	private static final int MAX_DISCOVERY_MS = 10_000;
 
 	private final AndroidExecutor androidExecutor;
-	private final Context appContext;
+	private final Application app;
 	private final Clock clock;
 
-	private volatile boolean wasEnabledByUs = false;
 	private volatile BluetoothStateReceiver receiver = null;
 
 	// Non-null if the plugin started successfully
 	private volatile BluetoothAdapter adapter = null;
 
 	AndroidBluetoothPlugin(BluetoothConnectionLimiter connectionLimiter,
-			TimeoutMonitor timeoutMonitor, Executor ioExecutor,
+			BluetoothConnectionFactory<BluetoothSocket> connectionFactory,
-			SecureRandom secureRandom, AndroidExecutor androidExecutor,
+			Executor ioExecutor,
-			Context appContext, Clock clock, Backoff backoff,
+			Executor wakefulIoExecutor,
-			PluginCallback callback, int maxLatency, int maxIdleTime) {
+			SecureRandom secureRandom,
-		super(connectionLimiter, timeoutMonitor, ioExecutor, secureRandom,
+			AndroidExecutor androidExecutor,
-				backoff, callback, maxLatency, maxIdleTime);
+			Application app,
+			Clock clock,
+			Backoff backoff,
+			PluginCallback callback,
+			int maxLatency,
+			int maxIdleTime) {
+		super(connectionLimiter, connectionFactory, ioExecutor,
+				wakefulIoExecutor, secureRandom, backoff, callback,
+				maxLatency, maxIdleTime);
 		this.androidExecutor = androidExecutor;
-		this.appContext = appContext;
+		this.app = app;
 		this.clock = clock;
 	}
 
@@ -96,13 +104,13 @@ class AndroidBluetoothPlugin extends BluetoothPlugin<BluetoothServerSocket> {
 		filter.addAction(ACTION_STATE_CHANGED);
 		filter.addAction(ACTION_SCAN_MODE_CHANGED);
 		receiver = new BluetoothStateReceiver();
-		appContext.registerReceiver(receiver, filter);
+		app.registerReceiver(receiver, filter);
 	}
 
 	@Override
 	public void stop() {
 		super.stop();
-		if (receiver != null) appContext.unregisterReceiver(receiver);
+		if (receiver != null) app.unregisterReceiver(receiver);
 	}
 
 	@Override
@@ -124,36 +132,10 @@ class AndroidBluetoothPlugin extends BluetoothPlugin<BluetoothServerSocket> {
 		return adapter != null && adapter.isEnabled();
 	}
 
-	@Override
-	void enableAdapter() {
-		if (adapter != null && !adapter.isEnabled()) {
-			if (adapter.enable()) {
-				LOG.info("Enabling Bluetooth");
-				wasEnabledByUs = true;
-			} else {
-				LOG.info("Could not enable Bluetooth");
-			}
-		}
-	}
-
-	@Override
-	void disableAdapterIfEnabledByUs() {
-		if (isAdapterEnabled() && wasEnabledByUs) {
-			if (adapter.disable()) LOG.info("Disabling Bluetooth");
-			else LOG.info("Could not disable Bluetooth");
-			wasEnabledByUs = false;
-		}
-	}
-
-	@Override
-	void setEnabledByUs() {
-		wasEnabledByUs = true;
-	}
-
 	@Override
 	@Nullable
 	String getBluetoothAddress() {
-		String address = AndroidUtils.getBluetoothAddress(appContext, adapter);
+		String address = AndroidUtils.getBluetoothAddress(app, adapter);
 		return address.isEmpty() ? null : address;
 	}
 
@@ -171,13 +153,7 @@ class AndroidBluetoothPlugin extends BluetoothPlugin<BluetoothServerSocket> {
 	@Override
 	DuplexTransportConnection acceptConnection(BluetoothServerSocket ss)
 			throws IOException {
-		return wrapSocket(ss.accept());
+		return connectionFactory.wrapSocket(this, ss.accept());
-	}
-
-	private DuplexTransportConnection wrapSocket(BluetoothSocket s)
-			throws IOException {
-		return new AndroidBluetoothTransportConnection(this, connectionLimiter,
-				timeoutMonitor, s);
 	}
 
 	@Override
@@ -194,7 +170,7 @@ class AndroidBluetoothPlugin extends BluetoothPlugin<BluetoothServerSocket> {
 		try {
 			s = d.createInsecureRfcommSocketToServiceRecord(u);
 			s.connect();
-			return wrapSocket(s);
+			return connectionFactory.wrapSocket(this, s);
 		} catch (IOException e) {
 			IoUtils.tryToClose(s, LOG, WARNING);
 			throw e;
@@ -229,7 +205,7 @@ class AndroidBluetoothPlugin extends BluetoothPlugin<BluetoothServerSocket> {
 		filter.addAction(ACTION_DISCOVERY_STARTED);
 		filter.addAction(ACTION_DISCOVERY_FINISHED);
 		filter.addAction(ACTION_FOUND);
-		appContext.registerReceiver(receiver, filter);
+		app.registerReceiver(receiver, filter);
 		try {
 			if (adapter.startDiscovery()) {
 				long now = clock.currentTimeMillis();
@@ -266,7 +242,7 @@ class AndroidBluetoothPlugin extends BluetoothPlugin<BluetoothServerSocket> {
 		} finally {
 			LOG.info("Cancelling discovery");
 			adapter.cancelDiscovery();
-			appContext.unregisterReceiver(receiver);
+			app.unregisterReceiver(receiver);
 		}
 		// Shuffle the addresses so we don't always try the same one first
 		shuffle(addresses);

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

@@ -1,9 +1,11 @@
 package org.briarproject.bramble.plugin.bluetooth;
 
-import android.content.Context;
+import android.app.Application;
+import android.bluetooth.BluetoothSocket;
 
 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.nullsafety.NotNullByDefault;
 import org.briarproject.bramble.api.plugin.Backoff;
 import org.briarproject.bramble.api.plugin.BackoffFactory;
@@ -12,12 +14,15 @@ 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.AndroidExecutor;
+import org.briarproject.bramble.api.system.AndroidWakeLockManager;
 import org.briarproject.bramble.api.system.Clock;
+import org.briarproject.bramble.api.system.WakefulIoExecutor;
 
 import java.security.SecureRandom;
 import java.util.concurrent.Executor;
 
 import javax.annotation.concurrent.Immutable;
+import javax.inject.Inject;
 
 import static org.briarproject.bramble.api.plugin.BluetoothConstants.ID;
 
@@ -31,22 +36,32 @@ public class AndroidBluetoothPluginFactory implements DuplexPluginFactory {
 	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 Executor ioExecutor, wakefulIoExecutor;
 	private final AndroidExecutor androidExecutor;
-	private final Context appContext;
+	private final AndroidWakeLockManager wakeLockManager;
+	private final Application app;
 	private final SecureRandom secureRandom;
 	private final EventBus eventBus;
 	private final Clock clock;
 	private final TimeoutMonitor timeoutMonitor;
 	private final BackoffFactory backoffFactory;
 
-	public AndroidBluetoothPluginFactory(Executor ioExecutor,
+	@Inject
-			AndroidExecutor androidExecutor, Context appContext,
+	public AndroidBluetoothPluginFactory(@IoExecutor Executor ioExecutor,
-			SecureRandom secureRandom, EventBus eventBus, Clock clock,
+			@WakefulIoExecutor Executor wakefulIoExecutor,
-			TimeoutMonitor timeoutMonitor, BackoffFactory backoffFactory) {
+			AndroidExecutor androidExecutor,
+			AndroidWakeLockManager wakeLockManager,
+			Application app,
+			SecureRandom secureRandom,
+			EventBus eventBus,
+			Clock clock,
+			TimeoutMonitor timeoutMonitor,
+			BackoffFactory backoffFactory) {
 		this.ioExecutor = ioExecutor;
+		this.wakefulIoExecutor = wakefulIoExecutor;
 		this.androidExecutor = androidExecutor;
-		this.appContext = appContext;
+		this.wakeLockManager = wakeLockManager;
+		this.app = app;
 		this.secureRandom = secureRandom;
 		this.eventBus = eventBus;
 		this.clock = clock;
@@ -67,13 +82,16 @@ public class AndroidBluetoothPluginFactory implements DuplexPluginFactory {
 	@Override
 	public DuplexPlugin createPlugin(PluginCallback callback) {
 		BluetoothConnectionLimiter connectionLimiter =
-				new BluetoothConnectionLimiterImpl(eventBus, clock);
+				new BluetoothConnectionLimiterImpl(eventBus);
+		BluetoothConnectionFactory<BluetoothSocket> connectionFactory =
+				new AndroidBluetoothConnectionFactory(connectionLimiter,
+						wakeLockManager, timeoutMonitor);
 		Backoff backoff = backoffFactory.createBackoff(MIN_POLLING_INTERVAL,
 				MAX_POLLING_INTERVAL, BACKOFF_BASE);
 		AndroidBluetoothPlugin plugin = new AndroidBluetoothPlugin(
-				connectionLimiter, timeoutMonitor, ioExecutor, secureRandom,
+				connectionLimiter, connectionFactory, ioExecutor,
-				androidExecutor, appContext, clock, backoff,
+				wakefulIoExecutor, secureRandom, androidExecutor, app,
-				callback, MAX_LATENCY, MAX_IDLE_TIME);
+				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

@@ -6,6 +6,8 @@ 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;
+import org.briarproject.bramble.api.system.AndroidWakeLock;
+import org.briarproject.bramble.api.system.AndroidWakeLockManager;
 
 import java.io.IOException;
 import java.io.InputStream;
@@ -21,16 +23,20 @@ class AndroidBluetoothTransportConnection
 	private final BluetoothConnectionLimiter connectionLimiter;
 	private final BluetoothSocket socket;
 	private final InputStream in;
+	private final AndroidWakeLock wakeLock;
 
 	AndroidBluetoothTransportConnection(Plugin plugin,
 			BluetoothConnectionLimiter connectionLimiter,
-			TimeoutMonitor timeoutMonitor, BluetoothSocket socket)
+			AndroidWakeLockManager wakeLockManager,
-			throws IOException {
+			TimeoutMonitor timeoutMonitor,
+			BluetoothSocket socket) throws IOException {
 		super(plugin);
 		this.connectionLimiter = connectionLimiter;
 		this.socket = socket;
 		in = timeoutMonitor.createTimeoutInputStream(
 				socket.getInputStream(), plugin.getMaxIdleTime() * 2);
+		wakeLock = wakeLockManager.createWakeLock("BluetoothConnection");
+		wakeLock.acquire();
 		String address = socket.getRemoteDevice().getAddress();
 		if (isValidBluetoothAddress(address)) remote.put(PROP_ADDRESS, address);
 	}
@@ -49,7 +55,9 @@ class AndroidBluetoothTransportConnection
 	protected void closeConnection(boolean exception) throws IOException {
 		try {
 			socket.close();
+			in.close();
 		} finally {
+			wakeLock.release();
 			connectionLimiter.connectionClosed(this);
 		}
 	}

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

@@ -1,23 +1,30 @@
 package org.briarproject.bramble.plugin.tcp;
 
-import android.content.Context;
+import android.annotation.TargetApi;
+import android.app.Application;
 import android.net.ConnectivityManager;
+import android.net.LinkAddress;
+import android.net.LinkProperties;
 import android.net.Network;
-import android.net.NetworkInfo;
+import android.net.NetworkCapabilities;
 import android.net.wifi.WifiInfo;
 import android.net.wifi.WifiManager;
 
 import org.briarproject.bramble.PoliteExecutor;
+import org.briarproject.bramble.api.Pair;
 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.InterfaceAddress;
+import java.net.NetworkInterface;
 import java.net.Socket;
+import java.net.SocketException;
 import java.net.UnknownHostException;
 import java.util.List;
 import java.util.concurrent.Executor;
@@ -28,14 +35,22 @@ import javax.net.SocketFactory;
 
 import static android.content.Context.CONNECTIVITY_SERVICE;
 import static android.content.Context.WIFI_SERVICE;
-import static android.net.ConnectivityManager.TYPE_WIFI;
+import static android.net.NetworkCapabilities.TRANSPORT_WIFI;
 import static android.os.Build.VERSION.SDK_INT;
 import static java.util.Collections.emptyList;
+import static java.util.Collections.list;
 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.nullsafety.NullSafety.requireNonNull;
+import static org.briarproject.bramble.api.plugin.LanTcpConstants.DEFAULT_PREF_PLUGIN_ENABLE;
+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;
+import static org.briarproject.bramble.util.LogUtils.logException;
 
 @NotNullByDefault
-class AndroidLanTcpPlugin extends LanTcpPlugin implements EventListener {
+class AndroidLanTcpPlugin extends LanTcpPlugin {
 
 	private static final Logger LOG =
 			getLogger(AndroidLanTcpPlugin.class.getName());
@@ -47,20 +62,22 @@ class AndroidLanTcpPlugin extends LanTcpPlugin implements EventListener {
 
 	private volatile SocketFactory socketFactory;
 
-	AndroidLanTcpPlugin(Executor ioExecutor, Context appContext,
+	AndroidLanTcpPlugin(Executor ioExecutor,
-			Backoff backoff, PluginCallback callback, int maxLatency,
+			Executor wakefulIoExecutor,
-			int maxIdleTime, int connectionTimeout) {
+			Application app,
-		super(ioExecutor, backoff, callback, maxLatency, maxIdleTime,
+			Backoff backoff,
-				connectionTimeout);
+			PluginCallback callback,
+			int maxLatency,
+			int maxIdleTime,
+			int connectionTimeout) {
+		super(ioExecutor, wakefulIoExecutor, backoff, callback, maxLatency,
+				maxIdleTime, connectionTimeout);
 		// Don't execute more than one connection status check at a time
 		connectionStatusExecutor =
 				new PoliteExecutor("AndroidLanTcpPlugin", ioExecutor, 1);
-		ConnectivityManager connectivityManager = (ConnectivityManager)
+		connectivityManager = (ConnectivityManager)
-				appContext.getSystemService(CONNECTIVITY_SERVICE);
+				requireNonNull(app.getSystemService(CONNECTIVITY_SERVICE));
-		if (connectivityManager == null) throw new AssertionError();
+		wifiManager = (WifiManager) app.getSystemService(WIFI_SERVICE);
-		this.connectivityManager = connectivityManager;
-		wifiManager = (WifiManager) appContext.getApplicationContext()
-				.getSystemService(WIFI_SERVICE);
 		socketFactory = SocketFactory.getDefault();
 	}
 
@@ -68,37 +85,137 @@ class AndroidLanTcpPlugin extends LanTcpPlugin implements EventListener {
 	public void start() {
 		if (used.getAndSet(true)) throw new IllegalStateException();
 		initialisePortProperty();
-		running = true;
+		Settings settings = callback.getSettings();
+		state.setStarted(settings.getBoolean(PREF_PLUGIN_ENABLE,
+				DEFAULT_PREF_PLUGIN_ENABLE));
 		updateConnectionStatus();
 	}
 
-	@Override
-	public void stop() {
-		running = false;
-		tryToClose(socket);
-	}
-
 	@Override
 	protected Socket createSocket() throws IOException {
 		return socketFactory.createSocket();
 	}
 
 	@Override
-	protected List<InetAddress> getUsableLocalInetAddresses() {
+	protected List<InetAddress> getUsableLocalInetAddresses(boolean ipv4) {
-		// If the device doesn't have wifi, don't open any sockets
+		InetAddress addr = getWifiAddress(ipv4);
-		if (wifiManager == null) return emptyList();
+		return addr == null ? emptyList() : singletonList(addr);
+	}
+
+	@Nullable
+	private InetAddress getWifiAddress(boolean ipv4) {
+		Pair<InetAddress, Boolean> wifi = getWifiIpv4Address();
+		if (ipv4) return wifi == null ? null : wifi.getFirst();
+		// If there's no wifi IPv4 address, we might be a client on an
+		// IPv6-only wifi network. We can only detect this on API 21+
+		if (wifi == null) {
+			return SDK_INT >= 21 ? getWifiClientIpv6Address() : null;
+		}
+		// Use the wifi IPv4 address to determine which interface's IPv6
+		// address we should return (if the interface has a suitable address)
+		return getIpv6AddressForInterface(wifi.getFirst());
+	}
+
+	/**
+	 * Returns a {@link Pair} where the first element is the IPv4 address of
+	 * the wifi interface and the second element is true if this device is
+	 * providing an access point, or false if this device is a client. Returns
+	 * null if this device isn't connected to wifi as an access point or client.
+	 */
+	@Nullable
+	private Pair<InetAddress, Boolean> getWifiIpv4Address() {
+		if (wifiManager == null) return null;
 		// If we're connected to a wifi network, return its address
 		WifiInfo info = wifiManager.getConnectionInfo();
 		if (info != null && info.getIpAddress() != 0) {
-			return singletonList(intToInetAddress(info.getIpAddress()));
+			return new Pair<>(intToInetAddress(info.getIpAddress()), false);
 		}
-		// If we're running an access point, return its address
+		List<InterfaceAddress> ifAddrs = getLocalInterfaceAddresses();
-		for (InetAddress addr : getLocalInetAddresses()) {
+		// If we're providing a normal access point, return its address
-			if (addr.equals(WIFI_AP_ADDRESS)) return singletonList(addr);
+		for (InterfaceAddress ifAddr : ifAddrs) {
-			if (addr.equals(WIFI_DIRECT_AP_ADDRESS)) return singletonList(addr);
+			if (isAndroidWifiApAddress(ifAddr)) {
+				return new Pair<>(ifAddr.getAddress(), true);
+			}
+		}
+		// If we're providing a wifi direct access point, return its address
+		for (InterfaceAddress ifAddr : ifAddrs) {
+			if (isAndroidWifiDirectApAddress(ifAddr)) {
+				return new Pair<>(ifAddr.getAddress(), true);
+			}
+		}
+		// Not connected to wifi
+		return null;
+	}
+
+	/**
+	 * Returns true if the given address belongs to a network provided by an
+	 * Android access point (including the access point's own address).
+	 * <p>
+	 * The access point's address is usually 192.168.43.1, but at least one
+	 * device (Honor 8A) may use other addresses in the range 192.168.43.0/24.
+	 */
+	private boolean isAndroidWifiApAddress(InterfaceAddress ifAddr) {
+		if (ifAddr.getNetworkPrefixLength() != 24) return false;
+		byte[] ip = ifAddr.getAddress().getAddress();
+		return ip.length == 4
+				&& ip[0] == (byte) 192
+				&& ip[1] == (byte) 168
+				&& ip[2] == (byte) 43;
+	}
+
+	/**
+	 * Returns true if the given address belongs to a network provided by an
+	 * Android wifi direct legacy mode access point (including the access
+	 * point's own address).
+	 */
+	private boolean isAndroidWifiDirectApAddress(InterfaceAddress ifAddr) {
+		if (ifAddr.getNetworkPrefixLength() != 24) return false;
+		byte[] ip = ifAddr.getAddress().getAddress();
+		return ip.length == 4
+				&& ip[0] == (byte) 192
+				&& ip[1] == (byte) 168
+				&& ip[2] == (byte) 49;
+	}
+
+	/**
+	 * Returns a link-local IPv6 address for the wifi client interface, or null
+	 * if there's no such interface or it doesn't have a suitable address.
+	 */
+	@TargetApi(21)
+	@Nullable
+	private InetAddress getWifiClientIpv6Address() {
+		for (Network net : connectivityManager.getAllNetworks()) {
+			NetworkCapabilities caps =
+					connectivityManager.getNetworkCapabilities(net);
+			if (caps == null || !caps.hasTransport(TRANSPORT_WIFI)) continue;
+			LinkProperties props = connectivityManager.getLinkProperties(net);
+			if (props == null) continue;
+			for (LinkAddress linkAddress : props.getLinkAddresses()) {
+				InetAddress addr = linkAddress.getAddress();
+				if (isIpv6LinkLocalAddress(addr)) return addr;
+			}
+		}
+		return null;
+	}
+
+	/**
+	 * Returns a link-local IPv6 address for the interface with the given IPv4
+	 * address, or null if the interface doesn't have a suitable address.
+	 */
+	@Nullable
+	private InetAddress getIpv6AddressForInterface(InetAddress ipv4) {
+		try {
+			NetworkInterface iface = NetworkInterface.getByInetAddress(ipv4);
+			if (iface == null) return null;
+			for (InetAddress addr : list(iface.getInetAddresses())) {
+				if (isIpv6LinkLocalAddress(addr)) return addr;
+			}
+			// No suitable address
+			return null;
+		} catch (SocketException e) {
+			logException(LOG, WARNING, e);
+			return null;
 		}
-		// No suitable addresses
-		return emptyList();
 	}
 
 	private InetAddress intToInetAddress(int ip) {
@@ -120,9 +237,11 @@ class AndroidLanTcpPlugin extends LanTcpPlugin implements EventListener {
 	private SocketFactory getSocketFactory() {
 		if (SDK_INT < 21) return SocketFactory.getDefault();
 		for (Network net : connectivityManager.getAllNetworks()) {
-			NetworkInfo info = connectivityManager.getNetworkInfo(net);
+			NetworkCapabilities caps =
-			if (info != null && info.getType() == TYPE_WIFI)
+					connectivityManager.getNetworkCapabilities(net);
+			if (caps != null && caps.hasTransport(TRANSPORT_WIFI)) {
 				return net.getSocketFactory();
+			}
 		}
 		LOG.warning("Could not find suitable socket factory");
 		return SocketFactory.getDefault();
@@ -130,31 +249,59 @@ class AndroidLanTcpPlugin extends LanTcpPlugin implements EventListener {
 
 	@Override
 	public void eventOccurred(Event e) {
+		super.eventOccurred(e);
 		if (e instanceof NetworkStatusEvent) updateConnectionStatus();
 	}
 
 	private void updateConnectionStatus() {
 		connectionStatusExecutor.execute(() -> {
-			if (!running) return;
+			State s = getState();
-			List<InetAddress> addrs = getUsableLocalInetAddresses();
+			if (s != ACTIVE && s != INACTIVE) return;
-			if (addrs.contains(WIFI_AP_ADDRESS)
+			Pair<InetAddress, Boolean> wifi = getPreferredWifiAddress();
-					|| addrs.contains(WIFI_DIRECT_AP_ADDRESS)) {
+			if (wifi == null) {
+				LOG.info("Not connected to wifi");
+				socketFactory = SocketFactory.getDefault();
+				// Server sockets may not have been closed automatically when
+				// interface was taken down. If any sockets are open, closing
+				// them here will cause the sockets to be cleared and the state
+				// to be updated in acceptContactConnections()
+				if (s == ACTIVE) {
+					LOG.info("Closing server sockets");
+					tryToClose(state.getServerSocket(true), LOG, WARNING);
+					tryToClose(state.getServerSocket(false), LOG, WARNING);
+				}
+			} else if (wifi.getSecond()) {
 				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 (socket == null || socket.isClosed()) bind();
+				bind();
-			} else if (addrs.isEmpty()) {
-				LOG.info("Not connected to wifi");
-				socketFactory = SocketFactory.getDefault();
-				tryToClose(socket);
 			} else {
 				LOG.info("Connected to wifi");
 				socketFactory = getSocketFactory();
-				if (socket == null || socket.isClosed()) bind();
+				bind();
 			}
 		});
 	}
+
+	/**
+	 * Returns a {@link Pair} where the first element is an IP address (IPv4 if
+	 * available, otherwise IPv6) of the wifi interface and the second element
+	 * is true if this device is providing an access point, or false if this
+	 * device is a client. Returns null if this device isn't connected to wifi
+	 * as an access point or client.
+	 */
+	@Nullable
+	private Pair<InetAddress, Boolean> getPreferredWifiAddress() {
+		Pair<InetAddress, Boolean> wifi = getWifiIpv4Address();
+		// If there's no wifi IPv4 address, we might be a client on an
+		// IPv6-only wifi network. We can only detect this on API 21+
+		if (wifi == null && SDK_INT >= 21) {
+			InetAddress ipv6 = getWifiClientIpv6Address();
+			if (ipv6 != null) return new Pair<>(ipv6, false);
+		}
+		return wifi;
+	}
 }

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

@@ -1,8 +1,9 @@
 package org.briarproject.bramble.plugin.tcp;
 
-import android.content.Context;
+import android.app.Application;
 
 import org.briarproject.bramble.api.event.EventBus;
+import org.briarproject.bramble.api.lifecycle.IoExecutor;
 import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
 import org.briarproject.bramble.api.plugin.Backoff;
 import org.briarproject.bramble.api.plugin.BackoffFactory;
@@ -10,10 +11,12 @@ 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.WakefulIoExecutor;
 
 import java.util.concurrent.Executor;
 
 import javax.annotation.concurrent.Immutable;
+import javax.inject.Inject;
 
 import static org.briarproject.bramble.api.plugin.LanTcpConstants.ID;
 
@@ -28,17 +31,22 @@ public class AndroidLanTcpPluginFactory implements DuplexPluginFactory {
 	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 Executor ioExecutor, wakefulIoExecutor;
 	private final EventBus eventBus;
 	private final BackoffFactory backoffFactory;
-	private final Context appContext;
+	private final Application app;
 
-	public AndroidLanTcpPluginFactory(Executor ioExecutor, EventBus eventBus,
+	@Inject
-			BackoffFactory backoffFactory, Context appContext) {
+	public AndroidLanTcpPluginFactory(@IoExecutor Executor ioExecutor,
+			@WakefulIoExecutor Executor wakefulIoExecutor,
+			EventBus eventBus,
+			BackoffFactory backoffFactory,
+			Application app) {
 		this.ioExecutor = ioExecutor;
+		this.wakefulIoExecutor = wakefulIoExecutor;
 		this.eventBus = eventBus;
 		this.backoffFactory = backoffFactory;
-		this.appContext = appContext;
+		this.app = app;
 	}
 
 	@Override
@@ -56,8 +64,8 @@ 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,
+				wakefulIoExecutor, app, backoff, callback,
-				CONNECTION_TIMEOUT);
+				MAX_LATENCY, MAX_IDLE_TIME, CONNECTION_TIMEOUT);
 		eventBus.addListener(plugin);
 		return plugin;
 	}

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

@@ -1,10 +1,9 @@
 package org.briarproject.bramble.plugin.tor;
 
-import android.content.Context;
+import android.app.Application;
 import android.content.pm.PackageInfo;
 import android.content.pm.PackageManager;
 import android.content.pm.PackageManager.NameNotFoundException;
-import android.os.PowerManager;
 
 import org.briarproject.bramble.api.battery.BatteryManager;
 import org.briarproject.bramble.api.network.NetworkManager;
@@ -12,48 +11,50 @@ import org.briarproject.bramble.api.nullsafety.MethodsNotNullByDefault;
 import org.briarproject.bramble.api.nullsafety.ParametersNotNullByDefault;
 import org.briarproject.bramble.api.plugin.Backoff;
 import org.briarproject.bramble.api.plugin.PluginCallback;
+import org.briarproject.bramble.api.system.AndroidWakeLock;
+import org.briarproject.bramble.api.system.AndroidWakeLockManager;
 import org.briarproject.bramble.api.system.Clock;
 import org.briarproject.bramble.api.system.LocationUtils;
 import org.briarproject.bramble.api.system.ResourceProvider;
-import org.briarproject.bramble.util.RenewableWakeLock;
 
+import java.io.File;
 import java.io.IOException;
 import java.util.concurrent.Executor;
-import java.util.concurrent.ScheduledExecutorService;
 
 import javax.net.SocketFactory;
 
-import static android.content.Context.MODE_PRIVATE;
-import static android.content.Context.POWER_SERVICE;
-import static android.os.PowerManager.PARTIAL_WAKE_LOCK;
-import static java.util.concurrent.TimeUnit.MINUTES;
-
 @MethodsNotNullByDefault
 @ParametersNotNullByDefault
 class AndroidTorPlugin extends TorPlugin {
 
-	private final Context appContext;
+	private final Application app;
-	private final RenewableWakeLock wakeLock;
+	private final AndroidWakeLock wakeLock;
 
-	AndroidTorPlugin(Executor ioExecutor, ScheduledExecutorService scheduler,
+	AndroidTorPlugin(Executor ioExecutor,
-			Context appContext, NetworkManager networkManager,
+			Executor wakefulIoExecutor,
-			LocationUtils locationUtils, SocketFactory torSocketFactory,
+			Application app,
-			Clock clock, ResourceProvider resourceProvider,
+			NetworkManager networkManager,
+			LocationUtils locationUtils,
+			SocketFactory torSocketFactory,
+			Clock clock,
+			ResourceProvider resourceProvider,
 			CircumventionProvider circumventionProvider,
-			BatteryManager batteryManager, Backoff backoff,
+			BatteryManager batteryManager,
+			AndroidWakeLockManager wakeLockManager,
+			Backoff backoff,
 			TorRendezvousCrypto torRendezvousCrypto,
-			PluginCallback callback, String architecture, int maxLatency,
+			PluginCallback callback,
-			int maxIdleTime) {
+			String architecture,
-		super(ioExecutor, networkManager, locationUtils, torSocketFactory,
+			int maxLatency,
-				clock, resourceProvider, circumventionProvider, batteryManager,
+			int maxIdleTime,
-				backoff, torRendezvousCrypto, callback, architecture, maxLatency, maxIdleTime,
+			File torDirectory) {
-				appContext.getDir("tor", MODE_PRIVATE));
+		super(ioExecutor, wakefulIoExecutor, networkManager, locationUtils,
-		this.appContext = appContext;
+				torSocketFactory, clock, resourceProvider,
-		PowerManager pm = (PowerManager)
+				circumventionProvider, batteryManager, backoff,
-				appContext.getSystemService(POWER_SERVICE);
+				torRendezvousCrypto, callback, architecture, maxLatency,
-		if (pm == null) throw new AssertionError();
+				maxIdleTime, torDirectory);
-		wakeLock = new RenewableWakeLock(pm, scheduler, PARTIAL_WAKE_LOCK,
+		this.app = app;
-				getWakeLockTag(), 1, MINUTES);
+		wakeLock = wakeLockManager.createWakeLock("TorPlugin");
 	}
 
 	@Override
@@ -64,8 +65,8 @@ class AndroidTorPlugin extends TorPlugin {
 	@Override
 	protected long getLastUpdateTime() {
 		try {
-			PackageManager pm = appContext.getPackageManager();
+			PackageManager pm = app.getPackageManager();
-			PackageInfo pi = pm.getPackageInfo(appContext.getPackageName(), 0);
+			PackageInfo pi = pm.getPackageInfo(app.getPackageName(), 0);
 			return pi.lastUpdateTime;
 		} catch (NameNotFoundException e) {
 			throw new AssertionError(e);
@@ -74,7 +75,6 @@ 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();
@@ -85,17 +85,4 @@ class AndroidTorPlugin extends TorPlugin {
 		super.stop();
 		wakeLock.release();
 	}
-
-	private String getWakeLockTag() {
-		PackageManager pm = appContext.getPackageManager();
-		for (PackageInfo info : pm.getInstalledPackages(0)) {
-			String name = info.packageName.toLowerCase();
-			if (name.startsWith("com.huawei.powergenie")) {
-				return "LocationManagerService";
-			} else if (name.startsWith("com.evenwell.powermonitor")) {
-				return "AudioIn";
-			}
-		}
-		return getClass().getSimpleName();
-	}
 }

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

@@ -1,28 +1,33 @@
 package org.briarproject.bramble.plugin.tor;
 
-import android.content.Context;
+import android.app.Application;
 
 import org.briarproject.bramble.api.battery.BatteryManager;
 import org.briarproject.bramble.api.event.EventBus;
+import org.briarproject.bramble.api.lifecycle.IoExecutor;
 import org.briarproject.bramble.api.network.NetworkManager;
 import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
 import org.briarproject.bramble.api.plugin.Backoff;
 import org.briarproject.bramble.api.plugin.BackoffFactory;
 import org.briarproject.bramble.api.plugin.PluginCallback;
 import org.briarproject.bramble.api.plugin.TorConstants;
+import org.briarproject.bramble.api.plugin.TorDirectory;
 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.AndroidWakeLockManager;
 import org.briarproject.bramble.api.system.Clock;
 import org.briarproject.bramble.api.system.LocationUtils;
 import org.briarproject.bramble.api.system.ResourceProvider;
+import org.briarproject.bramble.api.system.WakefulIoExecutor;
 import org.briarproject.bramble.util.AndroidUtils;
 
+import java.io.File;
 import java.util.concurrent.Executor;
-import java.util.concurrent.ScheduledExecutorService;
 import java.util.logging.Logger;
 
 import javax.annotation.concurrent.Immutable;
+import javax.inject.Inject;
 import javax.net.SocketFactory;
 
 @Immutable
@@ -38,9 +43,8 @@ public class AndroidTorPluginFactory implements DuplexPluginFactory {
 	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 Executor ioExecutor, wakefulIoExecutor;
-	private final ScheduledExecutorService scheduler;
+	private final Application app;
-	private final Context appContext;
 	private final NetworkManager networkManager;
 	private final LocationUtils locationUtils;
 	private final EventBus eventBus;
@@ -49,18 +53,28 @@ public class AndroidTorPluginFactory implements DuplexPluginFactory {
 	private final ResourceProvider resourceProvider;
 	private final CircumventionProvider circumventionProvider;
 	private final BatteryManager batteryManager;
+	private final AndroidWakeLockManager wakeLockManager;
 	private final Clock clock;
+	private final File torDirectory;
 
-	public AndroidTorPluginFactory(Executor ioExecutor,
+	@Inject
-			ScheduledExecutorService scheduler, Context appContext,
+	public AndroidTorPluginFactory(@IoExecutor Executor ioExecutor,
-			NetworkManager networkManager, LocationUtils locationUtils,
+			@WakefulIoExecutor Executor wakefulIoExecutor,
-			EventBus eventBus, SocketFactory torSocketFactory,
+			Application app,
-			BackoffFactory backoffFactory, ResourceProvider resourceProvider,
+			NetworkManager networkManager,
+			LocationUtils locationUtils,
+			EventBus eventBus,
+			SocketFactory torSocketFactory,
+			BackoffFactory backoffFactory,
+			ResourceProvider resourceProvider,
 			CircumventionProvider circumventionProvider,
-			BatteryManager batteryManager, Clock clock) {
+			BatteryManager batteryManager,
+			AndroidWakeLockManager wakeLockManager,
+			Clock clock,
+			@TorDirectory File torDirectory) {
 		this.ioExecutor = ioExecutor;
-		this.scheduler = scheduler;
+		this.wakefulIoExecutor = wakefulIoExecutor;
-		this.appContext = appContext;
+		this.app = app;
 		this.networkManager = networkManager;
 		this.locationUtils = locationUtils;
 		this.eventBus = eventBus;
@@ -69,7 +83,9 @@ public class AndroidTorPluginFactory implements DuplexPluginFactory {
 		this.resourceProvider = resourceProvider;
 		this.circumventionProvider = circumventionProvider;
 		this.batteryManager = batteryManager;
+		this.wakeLockManager = wakeLockManager;
 		this.clock = clock;
+		this.torDirectory = torDirectory;
 	}
 
 	@Override
@@ -112,11 +128,12 @@ public class AndroidTorPluginFactory implements DuplexPluginFactory {
 		Backoff backoff = backoffFactory.createBackoff(MIN_POLLING_INTERVAL,
 				MAX_POLLING_INTERVAL, BACKOFF_BASE);
 		TorRendezvousCrypto torRendezvousCrypto = new TorRendezvousCryptoImpl();
-		AndroidTorPlugin plugin = new AndroidTorPlugin(ioExecutor, scheduler,
+		AndroidTorPlugin plugin = new AndroidTorPlugin(ioExecutor,
-				appContext, networkManager, locationUtils, torSocketFactory,
+				wakefulIoExecutor, app, networkManager, locationUtils,
-				clock, resourceProvider, circumventionProvider, batteryManager,
+				torSocketFactory, clock, resourceProvider,
+				circumventionProvider, batteryManager, wakeLockManager,
 				backoff, torRendezvousCrypto, callback, architecture,
-				MAX_LATENCY, MAX_IDLE_TIME);
+				MAX_LATENCY, MAX_IDLE_TIME, torDirectory);
 		eventBus.addListener(plugin);
 		return plugin;
 	}

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

@@ -0,0 +1,18 @@
+package org.briarproject.bramble.system;
+
+import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
+
+@NotNullByDefault
+interface AlarmConstants {
+
+	/**
+	 * Request code for the broadcast intent attached to the periodic alarm.
+	 */
+	int REQUEST_ALARM = 1;
+
+	/**
+	 * Key for storing the process ID in the extras of the periodic alarm's
+	 * intent. This allows us to ignore alarms scheduled by dead processes.
+	 */
+	String EXTRA_PID = "org.briarproject.bramble.EXTRA_PID";
+}

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

@@ -0,0 +1,17 @@
+package org.briarproject.bramble.system;
+
+import android.content.BroadcastReceiver;
+import android.content.Context;
+import android.content.Intent;
+
+import org.briarproject.bramble.BrambleApplication;
+
+public class AlarmReceiver extends BroadcastReceiver {
+
+	@Override
+	public void onReceive(Context ctx, Intent intent) {
+		BrambleApplication app =
+				(BrambleApplication) ctx.getApplicationContext();
+		app.getBrambleAppComponent().alarmListener().onAlarm(intent);
+	}
+}

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.getNetworkCountryIso();
+		return tm == null ? "" : tm.getNetworkCountryIso();
 	}
 
 	private String getCountryFromSimCard() {
 		Object o = appContext.getSystemService(TELEPHONY_SERVICE);
 		TelephonyManager tm = (TelephonyManager) o;
-		return tm.getSimCountryIso();
+		return tm == null ? "" : tm.getSimCountryIso();
 	}
 }

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

@@ -1,12 +1,17 @@
 package org.briarproject.bramble.system;
 
 import org.briarproject.bramble.api.event.EventExecutor;
+import org.briarproject.bramble.api.lifecycle.LifecycleManager;
 import org.briarproject.bramble.api.system.AndroidExecutor;
+import org.briarproject.bramble.api.system.AndroidWakeLockManager;
 import org.briarproject.bramble.api.system.LocationUtils;
 import org.briarproject.bramble.api.system.ResourceProvider;
 import org.briarproject.bramble.api.system.SecureRandomProvider;
 
 import java.util.concurrent.Executor;
+import java.util.concurrent.RejectedExecutionHandler;
+import java.util.concurrent.ScheduledExecutorService;
+import java.util.concurrent.ScheduledThreadPoolExecutor;
 
 import javax.inject.Singleton;
 
@@ -16,6 +21,23 @@ import dagger.Provides;
 @Module
 public class AndroidSystemModule {
 
+	private final ScheduledExecutorService scheduledExecutorService;
+
+	public AndroidSystemModule() {
+		// Discard tasks that are submitted during shutdown
+		RejectedExecutionHandler policy =
+				new ScheduledThreadPoolExecutor.DiscardPolicy();
+		scheduledExecutorService = new ScheduledThreadPoolExecutor(1, policy);
+	}
+
+	@Provides
+	@Singleton
+	ScheduledExecutorService provideScheduledExecutorService(
+			LifecycleManager lifecycleManager) {
+		lifecycleManager.registerForShutdown(scheduledExecutorService);
+		return scheduledExecutorService;
+	}
+
 	@Provides
 	@Singleton
 	SecureRandomProvider provideSecureRandomProvider(
@@ -47,4 +69,11 @@ public class AndroidSystemModule {
 	ResourceProvider provideResourceProvider(AndroidResourceProvider provider) {
 		return provider;
 	}
+
+	@Provides
+	@Singleton
+	AndroidWakeLockManager provideWakeLockManager(
+			AndroidWakeLockManagerImpl wakeLockManager) {
+		return wakeLockManager;
+	}
 }

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

@@ -0,0 +1,242 @@
+package org.briarproject.bramble.system;
+
+import android.annotation.TargetApi;
+import android.app.AlarmManager;
+import android.app.Application;
+import android.app.PendingIntent;
+import android.content.Intent;
+import android.os.Process;
+import android.os.SystemClock;
+
+import org.briarproject.bramble.api.lifecycle.Service;
+import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
+import org.briarproject.bramble.api.system.AlarmListener;
+import org.briarproject.bramble.api.system.AndroidWakeLockManager;
+import org.briarproject.bramble.api.system.TaskScheduler;
+import org.briarproject.bramble.api.system.Wakeful;
+
+import java.util.ArrayList;
+import java.util.List;
+import java.util.PriorityQueue;
+import java.util.Queue;
+import java.util.concurrent.Executor;
+import java.util.concurrent.Future;
+import java.util.concurrent.ScheduledExecutorService;
+import java.util.concurrent.TimeUnit;
+import java.util.concurrent.atomic.AtomicBoolean;
+import java.util.logging.Logger;
+
+import javax.annotation.concurrent.GuardedBy;
+import javax.annotation.concurrent.ThreadSafe;
+
+import static android.app.AlarmManager.ELAPSED_REALTIME_WAKEUP;
+import static android.app.AlarmManager.INTERVAL_FIFTEEN_MINUTES;
+import static android.app.PendingIntent.FLAG_CANCEL_CURRENT;
+import static android.content.Context.ALARM_SERVICE;
+import static android.os.Build.VERSION.SDK_INT;
+import static java.util.Objects.requireNonNull;
+import static java.util.concurrent.TimeUnit.MILLISECONDS;
+import static java.util.logging.Level.INFO;
+import static java.util.logging.Logger.getLogger;
+import static org.briarproject.bramble.system.AlarmConstants.EXTRA_PID;
+import static org.briarproject.bramble.system.AlarmConstants.REQUEST_ALARM;
+
+@ThreadSafe
+@NotNullByDefault
+class AndroidTaskScheduler implements TaskScheduler, Service, AlarmListener {
+
+	private static final Logger LOG =
+			getLogger(AndroidTaskScheduler.class.getName());
+
+	private static final long ALARM_MS = INTERVAL_FIFTEEN_MINUTES;
+
+	private final Application app;
+	private final AndroidWakeLockManager wakeLockManager;
+	private final ScheduledExecutorService scheduledExecutorService;
+	private final AlarmManager alarmManager;
+
+	private final Object lock = new Object();
+	@GuardedBy("lock")
+	private final Queue<ScheduledTask> tasks = new PriorityQueue<>();
+
+	AndroidTaskScheduler(Application app,
+			AndroidWakeLockManager wakeLockManager,
+			ScheduledExecutorService scheduledExecutorService) {
+		this.app = app;
+		this.wakeLockManager = wakeLockManager;
+		this.scheduledExecutorService = scheduledExecutorService;
+		alarmManager = (AlarmManager)
+				requireNonNull(app.getSystemService(ALARM_SERVICE));
+	}
+
+	@Override
+	public void startService() {
+		scheduleAlarm();
+	}
+
+	@Override
+	public void stopService() {
+		cancelAlarm();
+	}
+
+	@Override
+	public Cancellable schedule(Runnable task, Executor executor, long delay,
+			TimeUnit unit) {
+		AtomicBoolean cancelled = new AtomicBoolean(false);
+		return schedule(task, executor, delay, unit, cancelled);
+	}
+
+	@Override
+	public Cancellable scheduleWithFixedDelay(Runnable task, Executor executor,
+			long delay, long interval, TimeUnit unit) {
+		AtomicBoolean cancelled = new AtomicBoolean(false);
+		return scheduleWithFixedDelay(task, executor, delay, interval, unit,
+				cancelled);
+	}
+
+	@Override
+	public void onAlarm(Intent intent) {
+		wakeLockManager.runWakefully(() -> {
+			int extraPid = intent.getIntExtra(EXTRA_PID, -1);
+			int currentPid = Process.myPid();
+			if (extraPid == currentPid) {
+				LOG.info("Alarm");
+				rescheduleAlarm();
+				runDueTasks();
+			} else if (LOG.isLoggable(INFO)) {
+				LOG.info("Ignoring alarm with PID " + extraPid
+						+ ", current PID is " + currentPid);
+			}
+		}, "TaskAlarm");
+	}
+
+	private Cancellable schedule(Runnable task, Executor executor, long delay,
+			TimeUnit unit, AtomicBoolean cancelled) {
+		long now = SystemClock.elapsedRealtime();
+		long dueMillis = now + MILLISECONDS.convert(delay, unit);
+		Runnable wakeful = () ->
+				wakeLockManager.executeWakefully(task, executor, "TaskHandoff");
+		Future<?> check = scheduleCheckForDueTasks(delay, unit);
+		ScheduledTask s = new ScheduledTask(wakeful, dueMillis, check,
+				cancelled);
+		synchronized (lock) {
+			tasks.add(s);
+		}
+		return s;
+	}
+
+	private Cancellable scheduleWithFixedDelay(Runnable task, Executor executor,
+			long delay, long interval, TimeUnit unit, AtomicBoolean cancelled) {
+		// All executions of this periodic task share a cancelled flag
+		Runnable wrapped = () -> {
+			task.run();
+			scheduleWithFixedDelay(task, executor, interval, interval, unit,
+					cancelled);
+		};
+		return schedule(wrapped, executor, delay, unit, cancelled);
+	}
+
+	private Future<?> scheduleCheckForDueTasks(long delay, TimeUnit unit) {
+		Runnable wakeful = () -> wakeLockManager.runWakefully(
+				this::runDueTasks, "TaskScheduler");
+		return scheduledExecutorService.schedule(wakeful, delay, unit);
+	}
+
+	@Wakeful
+	private void runDueTasks() {
+		long now = SystemClock.elapsedRealtime();
+		List<ScheduledTask> due = new ArrayList<>();
+		synchronized (lock) {
+			while (true) {
+				ScheduledTask s = tasks.peek();
+				if (s == null || s.dueMillis > now) break;
+				due.add(tasks.remove());
+			}
+		}
+		if (LOG.isLoggable(INFO)) {
+			LOG.info("Running " + due.size() + " due tasks");
+		}
+		for (ScheduledTask s : due) {
+			if (LOG.isLoggable(INFO)) {
+				LOG.info("Task is " + (now - s.dueMillis) + " ms overdue");
+			}
+			s.run();
+		}
+	}
+
+	private void scheduleAlarm() {
+		if (SDK_INT >= 23) scheduleIdleAlarm();
+		else scheduleInexactRepeatingAlarm();
+	}
+
+	private void rescheduleAlarm() {
+		// If SDK_INT < 23 the alarm repeats automatically
+		if (SDK_INT >= 23) scheduleIdleAlarm();
+	}
+
+	private void cancelAlarm() {
+		alarmManager.cancel(getAlarmPendingIntent());
+	}
+
+	private void scheduleInexactRepeatingAlarm() {
+		alarmManager.setInexactRepeating(ELAPSED_REALTIME_WAKEUP,
+				SystemClock.elapsedRealtime() + ALARM_MS, ALARM_MS,
+				getAlarmPendingIntent());
+	}
+
+	@TargetApi(23)
+	private void scheduleIdleAlarm() {
+		alarmManager.setAndAllowWhileIdle(ELAPSED_REALTIME_WAKEUP,
+				SystemClock.elapsedRealtime() + ALARM_MS,
+				getAlarmPendingIntent());
+	}
+
+	private PendingIntent getAlarmPendingIntent() {
+		Intent i = new Intent(app, AlarmReceiver.class);
+		i.putExtra(EXTRA_PID, android.os.Process.myPid());
+		return PendingIntent.getBroadcast(app, REQUEST_ALARM, i,
+				FLAG_CANCEL_CURRENT);
+	}
+
+	private class ScheduledTask
+			implements Runnable, Cancellable, Comparable<ScheduledTask> {
+
+		private final Runnable task;
+		private final long dueMillis;
+		private final Future<?> check;
+		private final AtomicBoolean cancelled;
+
+		public ScheduledTask(Runnable task, long dueMillis,
+				Future<?> check, AtomicBoolean cancelled) {
+			this.task = task;
+			this.dueMillis = dueMillis;
+			this.check = check;
+			this.cancelled = cancelled;
+		}
+
+		@Override
+		public void run() {
+			if (!cancelled.get()) task.run();
+		}
+
+		@Override
+		public void cancel() {
+			// Cancel any future executions of this task
+			cancelled.set(true);
+			// Cancel the scheduled check for due tasks
+			check.cancel(false);
+			// Remove the task from the queue
+			synchronized (lock) {
+				tasks.remove(this);
+			}
+		}
+
+		@Override
+		public int compareTo(ScheduledTask s) {
+			//noinspection UseCompareMethod
+			if (dueMillis < s.dueMillis) return -1;
+			if (dueMillis > s.dueMillis) return 1;
+			return 0;
+		}
+	}
+}

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

@@ -0,0 +1,49 @@
+package org.briarproject.bramble.system;
+
+import android.app.Application;
+
+import org.briarproject.bramble.api.lifecycle.LifecycleManager;
+import org.briarproject.bramble.api.system.AlarmListener;
+import org.briarproject.bramble.api.system.AndroidWakeLockManager;
+import org.briarproject.bramble.api.system.TaskScheduler;
+
+import java.util.concurrent.ScheduledExecutorService;
+
+import javax.inject.Inject;
+import javax.inject.Singleton;
+
+import dagger.Module;
+import dagger.Provides;
+
+@Module
+public class AndroidTaskSchedulerModule {
+
+	public static class EagerSingletons {
+		@Inject
+		AndroidTaskScheduler scheduler;
+	}
+
+	@Provides
+	@Singleton
+	AndroidTaskScheduler provideAndroidTaskScheduler(
+			LifecycleManager lifecycleManager, Application app,
+			AndroidWakeLockManager wakeLockManager,
+			ScheduledExecutorService scheduledExecutorService) {
+		AndroidTaskScheduler scheduler = new AndroidTaskScheduler(app,
+				wakeLockManager, scheduledExecutorService);
+		lifecycleManager.registerService(scheduler);
+		return scheduler;
+	}
+
+	@Provides
+	@Singleton
+	AlarmListener provideAlarmListener(AndroidTaskScheduler scheduler) {
+		return scheduler;
+	}
+
+	@Provides
+	@Singleton
+	TaskScheduler provideTaskScheduler(AndroidTaskScheduler scheduler) {
+		return scheduler;
+	}
+}

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

@@ -0,0 +1,74 @@
+package org.briarproject.bramble.system;
+
+import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
+import org.briarproject.bramble.api.system.AndroidWakeLock;
+
+import java.util.concurrent.atomic.AtomicInteger;
+import java.util.logging.Logger;
+
+import javax.annotation.concurrent.GuardedBy;
+import javax.annotation.concurrent.ThreadSafe;
+
+import static java.util.logging.Level.FINE;
+import static java.util.logging.Logger.getLogger;
+
+/**
+ * A wrapper around a {@link SharedWakeLock} that provides the more convenient
+ * semantics of {@link AndroidWakeLock} (i.e. calls to acquire() and release()
+ * don't need to be balanced).
+ */
+@ThreadSafe
+@NotNullByDefault
+class AndroidWakeLockImpl implements AndroidWakeLock {
+
+	private static final Logger LOG =
+			getLogger(AndroidWakeLockImpl.class.getName());
+
+	private static final AtomicInteger INSTANCE_ID = new AtomicInteger(0);
+
+	private final SharedWakeLock sharedWakeLock;
+	private final String tag;
+
+	private final Object lock = new Object();
+	@GuardedBy("lock")
+	private boolean held = false;
+
+	AndroidWakeLockImpl(SharedWakeLock sharedWakeLock, String tag) {
+		this.sharedWakeLock = sharedWakeLock;
+		this.tag = tag + "_" + INSTANCE_ID.getAndIncrement();
+	}
+
+	@Override
+	public void acquire() {
+		synchronized (lock) {
+			if (held) {
+				if (LOG.isLoggable(FINE)) {
+					LOG.fine(tag + " already acquired");
+				}
+			} else {
+				if (LOG.isLoggable(FINE)) {
+					LOG.fine(tag + " acquiring shared wake lock");
+				}
+				held = true;
+				sharedWakeLock.acquire();
+			}
+		}
+	}
+
+	@Override
+	public void release() {
+		synchronized (lock) {
+			if (held) {
+				if (LOG.isLoggable(FINE)) {
+					LOG.fine(tag + " releasing shared wake lock");
+				}
+				held = false;
+				sharedWakeLock.release();
+			} else {
+				if (LOG.isLoggable(FINE)) {
+					LOG.fine(tag + " already released");
+				}
+			}
+		}
+	}
+}

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

@@ -0,0 +1,119 @@
+package org.briarproject.bramble.system;
+
+import android.app.Application;
+import android.content.Context;
+import android.content.pm.PackageInfo;
+import android.content.pm.PackageManager;
+import android.os.PowerManager;
+
+import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
+import org.briarproject.bramble.api.system.AndroidWakeLock;
+import org.briarproject.bramble.api.system.AndroidWakeLockManager;
+
+import java.util.concurrent.Executor;
+import java.util.concurrent.ScheduledExecutorService;
+
+import javax.inject.Inject;
+
+import static android.content.Context.POWER_SERVICE;
+import static android.os.PowerManager.PARTIAL_WAKE_LOCK;
+import static java.util.concurrent.TimeUnit.MINUTES;
+import static java.util.concurrent.TimeUnit.SECONDS;
+import static org.briarproject.bramble.api.nullsafety.NullSafety.requireNonNull;
+
+@NotNullByDefault
+class AndroidWakeLockManagerImpl implements AndroidWakeLockManager {
+
+	/**
+	 * How often to replace the wake lock.
+	 */
+	private static final long LOCK_DURATION_MS = MINUTES.toMillis(1);
+
+	/**
+	 * Automatically release the lock this many milliseconds after it's due
+	 * to have been replaced and released.
+	 */
+	private static final long SAFETY_MARGIN_MS = SECONDS.toMillis(30);
+
+	private final SharedWakeLock sharedWakeLock;
+
+	@Inject
+	AndroidWakeLockManagerImpl(Application app,
+			ScheduledExecutorService scheduledExecutorService) {
+		PowerManager powerManager = (PowerManager)
+				requireNonNull(app.getSystemService(POWER_SERVICE));
+		String tag = getWakeLockTag(app);
+		sharedWakeLock = new RenewableWakeLock(powerManager,
+				scheduledExecutorService, PARTIAL_WAKE_LOCK, tag,
+				LOCK_DURATION_MS, SAFETY_MARGIN_MS);
+	}
+
+	@Override
+	public AndroidWakeLock createWakeLock(String tag) {
+		return new AndroidWakeLockImpl(sharedWakeLock, tag);
+	}
+
+	@Override
+	public void runWakefully(Runnable r, String tag) {
+		AndroidWakeLock wakeLock = createWakeLock(tag);
+		wakeLock.acquire();
+		try {
+			r.run();
+		} finally {
+			wakeLock.release();
+		}
+	}
+
+	@Override
+	public void executeWakefully(Runnable r, Executor executor, String tag) {
+		AndroidWakeLock wakeLock = createWakeLock(tag);
+		wakeLock.acquire();
+		try {
+			executor.execute(() -> {
+				try {
+					r.run();
+				} finally {
+					// Release the wake lock if the task throws an exception
+					wakeLock.release();
+				}
+			});
+		} catch (Exception e) {
+			// Release the wake lock if the executor throws an exception when
+			// we submit the task (in which case the release() call above won't
+			// happen)
+			wakeLock.release();
+			throw e;
+		}
+	}
+
+	@Override
+	public void executeWakefully(Runnable r, String tag) {
+		AndroidWakeLock wakeLock = createWakeLock(tag);
+		wakeLock.acquire();
+		try {
+			new Thread(() -> {
+				try {
+					r.run();
+				} finally {
+					wakeLock.release();
+				}
+			}).start();
+		} catch (Exception e) {
+			wakeLock.release();
+			throw e;
+		}
+	}
+
+	private String getWakeLockTag(Context ctx) {
+		PackageManager pm = ctx.getPackageManager();
+		for (PackageInfo info : pm.getInstalledPackages(0)) {
+			String name = info.packageName.toLowerCase();
+			if (name.startsWith("com.huawei.powergenie")) {
+				return "LocationManagerService";
+			} else if (name.startsWith("com.evenwell.powermonitor")) {
+				return "AudioIn";
+			}
+		}
+		return ctx.getPackageName();
+	}
+}

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

@@ -0,0 +1,23 @@
+package org.briarproject.bramble.system;
+
+import org.briarproject.bramble.api.lifecycle.IoExecutor;
+import org.briarproject.bramble.api.system.AndroidWakeLockManager;
+import org.briarproject.bramble.api.system.WakefulIoExecutor;
+
+import java.util.concurrent.Executor;
+
+import dagger.Module;
+import dagger.Provides;
+
+@Module
+public
+class AndroidWakefulIoExecutorModule {
+
+	@Provides
+	@WakefulIoExecutor
+	Executor provideWakefulIoExecutor(@IoExecutor Executor ioExecutor,
+			AndroidWakeLockManager wakeLockManager) {
+		return r -> wakeLockManager.executeWakefully(r, ioExecutor,
+				"WakefulIoExecutor");
+	}
+}

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

@@ -0,0 +1,130 @@
+package org.briarproject.bramble.system;
+
+import android.os.PowerManager;
+import android.os.PowerManager.WakeLock;
+
+import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
+
+import java.util.concurrent.Future;
+import java.util.concurrent.ScheduledExecutorService;
+import java.util.logging.Logger;
+
+import javax.annotation.Nullable;
+import javax.annotation.concurrent.GuardedBy;
+import javax.annotation.concurrent.ThreadSafe;
+
+import static java.util.concurrent.TimeUnit.MILLISECONDS;
+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.nullsafety.NullSafety.requireNonNull;
+
+@ThreadSafe
+@NotNullByDefault
+class RenewableWakeLock implements SharedWakeLock {
+
+	private static final Logger LOG =
+			getLogger(RenewableWakeLock.class.getName());
+
+	private final PowerManager powerManager;
+	private final ScheduledExecutorService scheduledExecutorService;
+	private final int levelAndFlags;
+	private final String tag;
+	private final long durationMs, safetyMarginMs;
+
+	private final Object lock = new Object();
+	@GuardedBy("lock")
+	@Nullable
+	private WakeLock wakeLock;
+	@GuardedBy("lock")
+	@Nullable
+	private Future<?> future;
+	@GuardedBy("lock")
+	private int refCount = 0;
+	@GuardedBy("lock")
+	private long acquired = 0;
+
+	RenewableWakeLock(PowerManager powerManager,
+			ScheduledExecutorService scheduledExecutorService,
+			int levelAndFlags,
+			String tag,
+			long durationMs,
+			long safetyMarginMs) {
+		this.powerManager = powerManager;
+		this.scheduledExecutorService = scheduledExecutorService;
+		this.levelAndFlags = levelAndFlags;
+		this.tag = tag;
+		this.durationMs = durationMs;
+		this.safetyMarginMs = safetyMarginMs;
+	}
+
+	@Override
+	public void acquire() {
+		synchronized (lock) {
+			refCount++;
+			if (refCount == 1) {
+				if (LOG.isLoggable(INFO)) {
+					LOG.info("Acquiring wake lock " + tag);
+				}
+				wakeLock = powerManager.newWakeLock(levelAndFlags, tag);
+				// We do our own reference counting so we can replace the lock
+				// TODO: Check whether using a ref-counted wake lock affects
+				//  power management apps
+				wakeLock.setReferenceCounted(false);
+				wakeLock.acquire(durationMs + safetyMarginMs);
+				future = scheduledExecutorService.schedule(this::renew,
+						durationMs, MILLISECONDS);
+				acquired = android.os.SystemClock.elapsedRealtime();
+			} else if (LOG.isLoggable(FINE)) {
+				LOG.fine("Wake lock " + tag + " has " + refCount + " holders");
+			}
+		}
+	}
+
+	private void renew() {
+		if (LOG.isLoggable(INFO)) LOG.info("Renewing wake lock " + tag);
+		synchronized (lock) {
+			if (wakeLock == null) {
+				LOG.info("Already released");
+				return;
+			}
+			if (LOG.isLoggable(FINE)) {
+				LOG.fine("Wake lock " + tag + " has " + refCount + " holders");
+			}
+			long now = android.os.SystemClock.elapsedRealtime();
+			long expiry = acquired + durationMs + safetyMarginMs;
+			if (now > expiry && LOG.isLoggable(WARNING)) {
+				LOG.warning("Wake lock expired " + (now - expiry) + " ms ago");
+			}
+			WakeLock oldWakeLock = wakeLock;
+			wakeLock = powerManager.newWakeLock(levelAndFlags, tag);
+			wakeLock.setReferenceCounted(false);
+			wakeLock.acquire(durationMs + safetyMarginMs);
+			oldWakeLock.release();
+			future = scheduledExecutorService.schedule(this::renew, durationMs,
+					MILLISECONDS);
+			acquired = now;
+		}
+	}
+
+	@Override
+	public void release() {
+		synchronized (lock) {
+			refCount--;
+			if (refCount == 0) {
+				if (LOG.isLoggable(INFO)) {
+					LOG.info("Releasing wake lock " + tag);
+				}
+				requireNonNull(future).cancel(false);
+				future = null;
+				requireNonNull(wakeLock).release();
+				wakeLock = null;
+				acquired = 0;
+			} else if (LOG.isLoggable(FINE)) {
+				LOG.fine("Wake lock " + tag + " has " + refCount + " holders");
+			}
+		}
+	}
+}
+

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

@@ -0,0 +1,22 @@
+package org.briarproject.bramble.system;
+
+import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
+import org.briarproject.bramble.api.system.AndroidWakeLock;
+
+@NotNullByDefault
+interface SharedWakeLock {
+
+	/**
+	 * Acquires the wake lock. This increments the wake lock's reference count,
+	 * so unlike {@link AndroidWakeLock#acquire()} every call to this method
+	 * must be followed by a balancing call to {@link #release()}.
+	 */
+	void acquire();
+
+	/**
+	 * Releases the wake lock. This decrements the wake lock's reference count,
+	 * so unlike {@link AndroidWakeLock#release()} every call to this method
+	 * must follow a balancing call to {@link #acquire()}.
+	 */
+	void release();
+}

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

@@ -1,100 +0,0 @@
-package org.briarproject.bramble.util;
-
-import android.os.PowerManager;
-
-import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
-
-import java.util.concurrent.ScheduledExecutorService;
-import java.util.concurrent.ScheduledFuture;
-import java.util.concurrent.TimeUnit;
-import java.util.logging.Logger;
-
-import javax.annotation.Nullable;
-import javax.annotation.concurrent.ThreadSafe;
-
-import static java.util.concurrent.TimeUnit.MILLISECONDS;
-import static java.util.logging.Level.INFO;
-
-@ThreadSafe
-@NotNullByDefault
-public class RenewableWakeLock {
-
-	private static final Logger LOG =
-			Logger.getLogger(RenewableWakeLock.class.getName());
-
-	/**
-	 * Automatically release the lock this many milliseconds after it's due
-	 * to have been replaced and released.
-	 */
-	private static final int SAFETY_MARGIN_MS = 10_000;
-
-	private final PowerManager powerManager;
-	private final ScheduledExecutorService scheduler;
-	private final int levelAndFlags;
-	private final String tag;
-	private final long durationMs;
-	private final Runnable renewTask;
-
-	private final Object lock = new Object();
-	@Nullable
-	private PowerManager.WakeLock wakeLock; // Locking: lock
-	@Nullable
-	private ScheduledFuture future; // Locking: lock
-
-	public RenewableWakeLock(PowerManager powerManager,
-			ScheduledExecutorService scheduler, int levelAndFlags, String tag,
-			long duration, TimeUnit timeUnit) {
-		this.powerManager = powerManager;
-		this.scheduler = scheduler;
-		this.levelAndFlags = levelAndFlags;
-		this.tag = tag;
-		durationMs = MILLISECONDS.convert(duration, timeUnit);
-		renewTask = this::renew;
-	}
-
-	public void acquire() {
-		if (LOG.isLoggable(INFO)) LOG.info("Acquiring wake lock " + tag);
-		synchronized (lock) {
-			if (wakeLock != null) {
-				LOG.info("Already acquired");
-				return;
-			}
-			wakeLock = powerManager.newWakeLock(levelAndFlags, tag);
-			wakeLock.setReferenceCounted(false);
-			wakeLock.acquire(durationMs + SAFETY_MARGIN_MS);
-			future = scheduler.schedule(renewTask, durationMs, MILLISECONDS);
-		}
-	}
-
-	private void renew() {
-		if (LOG.isLoggable(INFO)) LOG.info("Renewing wake lock " + tag);
-		synchronized (lock) {
-			if (wakeLock == null) {
-				LOG.info("Already released");
-				return;
-			}
-			PowerManager.WakeLock oldWakeLock = wakeLock;
-			wakeLock = powerManager.newWakeLock(levelAndFlags, tag);
-			wakeLock.setReferenceCounted(false);
-			wakeLock.acquire(durationMs + SAFETY_MARGIN_MS);
-			oldWakeLock.release();
-			future = scheduler.schedule(renewTask, durationMs, MILLISECONDS);
-		}
-	}
-
-	public void release() {
-		if (LOG.isLoggable(INFO)) LOG.info("Releasing wake lock " + tag);
-		synchronized (lock) {
-			if (wakeLock == null) {
-				LOG.info("Already released");
-				return;
-			}
-			if (future == null) throw new AssertionError();
-			future.cancel(false);
-			future = null;
-			wakeLock.release();
-			wakeLock = null;
-		}
-	}
-}
-

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

@@ -18,6 +18,8 @@ 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

@@ -7,6 +7,10 @@ public interface TimeoutMonitor {
 	/**
 	 * Returns an {@link InputStream} that wraps the given stream and allows
 	 * read timeouts to be detected.
+	 * <p>
+	 * The returned stream must be {@link InputStream#close() closed} when it's
+	 * no longer needed to ensure that resources held by the timeout monitor
+	 * are released.
 	 *
 	 * @param timeoutMs The read timeout in milliseconds. Timeouts will be
 	 * detected eventually but are not guaranteed to be detected immediately.

bramble-api/src/main/java/org/briarproject/bramble/api/lifecycle/LifecycleManager.java

@@ -5,6 +5,7 @@ import org.briarproject.bramble.api.db.DatabaseComponent;
 import org.briarproject.bramble.api.db.DbException;
 import org.briarproject.bramble.api.db.Transaction;
 import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
+import org.briarproject.bramble.api.system.Wakeful;
 
 import java.util.concurrent.ExecutorService;
 
@@ -65,6 +66,7 @@ public interface LifecycleManager {
 	 * Opens the {@link DatabaseComponent} using the given key and starts any
 	 * registered {@link Service Services}.
 	 */
+	@Wakeful
 	StartResult startServices(SecretKey dbKey);
 
 	/**
@@ -72,6 +74,7 @@ public interface LifecycleManager {
 	 * registered {@link ExecutorService ExecutorServices}, and closes the
 	 * {@link DatabaseComponent}.
 	 */
+	@Wakeful
 	void stopServices();
 
 	/**
@@ -104,6 +107,7 @@ public interface LifecycleManager {
 		 *
 		 * @param txn A read-write transaction
 		 */
+		@Wakeful
 		void onDatabaseOpened(Transaction txn) throws DbException;
 	}
 }

bramble-api/src/main/java/org/briarproject/bramble/api/lifecycle/Service.java

@@ -1,16 +1,20 @@
 package org.briarproject.bramble.api.lifecycle;
 
+import org.briarproject.bramble.api.system.Wakeful;
+
 public interface Service {
 
 	/**
-	 * Starts the service.This method must not be called concurrently with
+	 * Starts the service. This method must not be called concurrently with
 	 * {@link #stopService()}.
 	 */
+	@Wakeful
 	void startService() throws ServiceException;
 
 	/**
 	 * Stops the service. This method must not be called concurrently with
 	 * {@link #startService()}.
 	 */
+	@Wakeful
 	void stopService() throws ServiceException;
 }

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

@@ -6,8 +6,16 @@ public interface BluetoothConstants {
 
 	int UUID_BYTES = 16;
 
+	// Transport properties
 	String PROP_ADDRESS = "address";
 	String PROP_UUID = "uuid";
 
-	String PREF_BT_ENABLE = "enable";
+	// Local settings (not shared with contacts)
+	String PREF_ADDRESS_IS_REFLECTED = "addressIsReflected";
+	String PREF_EVER_CONNECTED = "everConnected";
+
+	// Default values for local settings
+	boolean DEFAULT_PREF_PLUGIN_ENABLE = false;
+	boolean DEFAULT_PREF_ADDRESS_IS_REFLECTED = false;
+	boolean DEFAULT_PREF_EVER_CONNECTED = false;
 }

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

@@ -7,7 +7,12 @@ public interface LanTcpConstants {
 	// Transport properties (shared with contacts)
 	String PROP_IP_PORTS = "ipPorts";
 	String PROP_PORT = "port";
+	String PROP_IPV6 = "ipv6";
 
-	// A local setting
+	// Local settings (not shared with contacts)
 	String PREF_LAN_IP_PORTS = "ipPorts";
+	String PREF_IPV6 = "ipv6";
+
+	// Default value for PREF_PLUGIN_ENABLE
+	boolean DEFAULT_PREF_PLUGIN_ENABLE = true;
 }

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

@@ -3,12 +3,56 @@ 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 org.briarproject.bramble.api.system.Wakeful;
 
 import java.util.Collection;
 
 @NotNullByDefault
 public interface Plugin {
 
+	enum State {
+
+		/**
+		 * The plugin has not finished starting or has been stopped.
+		 */
+		STARTING_STOPPING,
+
+		/**
+		 * The plugin is disabled by settings. Use {@link #getReasonsDisabled()}
+		 * to find out which settings are responsible.
+		 */
+		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 flag returned by {@link #getReasonsDisabled()} to indicate that
+	 * the plugin has been disabled by the user.
+	 */
+	int REASON_USER = 1;
+
 	/**
 	 * Returns the plugin's transport identifier.
 	 */
@@ -27,17 +71,28 @@ public interface Plugin {
 	/**
 	 * Starts the plugin.
 	 */
+	@Wakeful
 	void start() throws PluginException;
 
 	/**
 	 * Stops the plugin.
 	 */
+	@Wakeful
 	void stop() throws PluginException;
 
 	/**
-	 * Returns true if the plugin is running.
+	 * Returns the current state of the plugin.
 	 */
-	boolean isRunning();
+	State getState();
+
+	/**
+	 * Returns a set of flags indicating why the plugin is
+	 * {@link State#DISABLED disabled}, or 0 if the plugin is not disabled.
+	 * <p>
+	 * The flags used are plugin-specific, except the generic flag
+	 * {@link #REASON_USER}, which may be used by any plugin.
+	 */
+	int getReasonsDisabled();
 
 	/**
 	 * Returns true if the plugin should be polled periodically to attempt to
@@ -54,6 +109,7 @@ public interface Plugin {
 	 * Attempts to create connections using the given transport properties,
 	 * passing any created connections to the corresponding handlers.
 	 */
+	@Wakeful
 	void poll(Collection<Pair<TransportProperties, ConnectionHandler>>
 			properties);
 }

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

@@ -1,9 +1,15 @@
 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;
 
+import java.util.Collection;
+
 /**
  * An interface through which a transport plugin interacts with the rest of
  * the application.
@@ -21,6 +27,11 @@ public interface PluginCallback extends ConnectionHandler {
 	 */
 	TransportProperties getLocalProperties();
 
+	/**
+	 * Returns the plugin's remote transport properties.
+	 */
+	Collection<TransportProperties> getRemoteProperties();
+
 	/**
 	 * Merges the given settings with the plugin's settings
 	 */
@@ -32,12 +43,17 @@ public interface PluginCallback extends ConnectionHandler {
 	void mergeLocalProperties(TransportProperties p);
 
 	/**
-	 * Signals that the transport is enabled.
+	 * 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.
 	 */
-	void transportEnabled();
+	void pluginStateChanged(State state);
-
-	/**
-	 * Signals that the transport is disabled.
-	 */
-	void transportDisabled();
 }

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

@@ -41,4 +41,17 @@ 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

@@ -1,9 +1,12 @@
 package org.briarproject.bramble.api.plugin;
 
+import static java.util.concurrent.TimeUnit.DAYS;
+
 public interface TorConstants {
 
 	TransportId ID = new TransportId("org.briarproject.bramble.tor");
 
+	// Transport properties
 	String PROP_ONION_V2 = "onion";
 	String PROP_ONION_V3 = "onion3";
 
@@ -13,14 +16,45 @@ public interface TorConstants {
 	int CONNECT_TO_PROXY_TIMEOUT = 5000; // Milliseconds
 	int EXTRA_SOCKET_TIMEOUT = 30000; // Milliseconds
 
+	// Local settings (not shared with contacts)
 	String PREF_TOR_NETWORK = "network2";
 	String PREF_TOR_PORT = "port";
 	String PREF_TOR_MOBILE = "useMobileData";
 	String PREF_TOR_ONLY_WHEN_CHARGING = "onlyWhenCharging";
+	String HS_PRIVATE_KEY_V2 = "onionPrivKey";
+	String HS_PRIVATE_KEY_V3 = "onionPrivKey3";
+	String HS_V3_CREATED = "onionPrivKey3Created";
 
+	/**
+	 * How long to publish a v3 hidden service before retiring the v2 service.
+	 */
+	long V3_MIGRATION_PERIOD_MS = DAYS.toMillis(180);
+
+	// Values for PREF_TOR_NETWORK
 	int PREF_TOR_NETWORK_AUTOMATIC = 0;
 	int PREF_TOR_NETWORK_WITHOUT_BRIDGES = 1;
 	int PREF_TOR_NETWORK_WITH_BRIDGES = 2;
+	// TODO: Remove when settings migration code is removed
 	int PREF_TOR_NETWORK_NEVER = 3;
 
+	// Default values for local settings
+	boolean DEFAULT_PREF_PLUGIN_ENABLE = true;
+	int DEFAULT_PREF_TOR_NETWORK = PREF_TOR_NETWORK_AUTOMATIC;
+	boolean DEFAULT_PREF_TOR_MOBILE = true;
+	boolean DEFAULT_PREF_TOR_ONLY_WHEN_CHARGING = false;
+
+	/**
+	 * Reason flag returned by {@link Plugin#getReasonsDisabled()}.
+	 */
+	int REASON_BATTERY = 2;
+
+	/**
+	 * Reason flag returned by {@link Plugin#getReasonsDisabled()}.
+	 */
+	int REASON_MOBILE_DATA = 4;
+
+	/**
+	 * Reason flag returned by {@link Plugin#getReasonsDisabled()}.
+	 */
+	int REASON_COUNTRY_BLOCKED = 8;
 }

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

@@ -1,5 +1,6 @@
-package org.briarproject.bramble.api.system;
+package org.briarproject.bramble.api.plugin;
 
+import java.io.File;
 import java.lang.annotation.Retention;
 import java.lang.annotation.Target;
 
@@ -11,15 +12,11 @@ import static java.lang.annotation.ElementType.PARAMETER;
 import static java.lang.annotation.RetentionPolicy.RUNTIME;
 
 /**
- * Annotation for injecting a scheduled executor service
+ * Annotation for injecting the {@link File directory} where the Tor plugin
- * that can be used to schedule the execution of tasks.
+ * should store its state.
- * <p>
- * The service should <b>only</b> be used for running tasks on other executors
- * at scheduled times.
- * No significant work should be run by the service itself!
  */
 @Qualifier
 @Target({FIELD, METHOD, PARAMETER})
 @Retention(RUNTIME)
-public @interface Scheduler {
+public @interface TorDirectory {
 }

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

@@ -4,4 +4,7 @@ public interface WanTcpConstants {
 
 	TransportId ID = new TransportId("org.briarproject.bramble.wan");
 
+	// Default value for PREF_PLUGIN_ENABLE
+	boolean DEFAULT_PREF_PLUGIN_ENABLE = false;
 }
+

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

@@ -8,6 +8,7 @@ import org.briarproject.bramble.api.plugin.Plugin;
 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.system.Wakeful;
 
 import javax.annotation.Nullable;
 
@@ -21,6 +22,7 @@ public interface DuplexPlugin extends Plugin {
 	 * Attempts to create and return a connection using the given transport
 	 * properties. Returns null if a connection cannot be created.
 	 */
+	@Wakeful
 	@Nullable
 	DuplexTransportConnection createConnection(TransportProperties p);
 

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

@@ -1,15 +0,0 @@
-package org.briarproject.bramble.api.plugin.event;
-
-import org.briarproject.bramble.api.event.Event;
-import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
-
-import javax.annotation.concurrent.Immutable;
-
-/**
- * An event that informs the Bluetooth plugin that we have enabled the
- * Bluetooth adapter.
- */
-@Immutable
-@NotNullByDefault
-public class BluetoothEnabledEvent extends Event {
-}

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

@@ -1,15 +0,0 @@
-package org.briarproject.bramble.api.plugin.event;
-
-import org.briarproject.bramble.api.event.Event;
-import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
-
-import javax.annotation.concurrent.Immutable;
-
-/**
- * An event that asks the Bluetooth plugin to disable the Bluetooth adapter if
- * we previously enabled it.
- */
-@Immutable
-@NotNullByDefault
-public class DisableBluetoothEvent extends Event {
-}

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

@@ -1,14 +0,0 @@
-package org.briarproject.bramble.api.plugin.event;
-
-import org.briarproject.bramble.api.event.Event;
-import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
-
-import javax.annotation.concurrent.Immutable;
-
-/**
- * An event that asks the Bluetooth plugin to enable the Bluetooth adapter.
- */
-@Immutable
-@NotNullByDefault
-public class EnableBluetoothEvent extends Event {
-}

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

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

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

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

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

@@ -0,0 +1,32 @@
+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 the {@link State state} of a plugin changes.
+ */
+@Immutable
+@NotNullByDefault
+public class TransportStateEvent extends Event {
+
+	private final TransportId transportId;
+	private final State state;
+
+	public TransportStateEvent(TransportId transportId, State state) {
+		this.transportId = transportId;
+		this.state = state;
+	}
+
+	public TransportId getTransportId() {
+		return transportId;
+	}
+
+	public State getState() {
+		return state;
+	}
+}

bramble-api/src/main/java/org/briarproject/bramble/api/plugin/simplex/SimplexPlugin.java

@@ -5,6 +5,7 @@ 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 org.briarproject.bramble.api.system.Wakeful;
 
 import javax.annotation.Nullable;
 
@@ -18,6 +19,7 @@ public interface SimplexPlugin extends Plugin {
 	 * Attempts to create and return a reader for the given transport
 	 * properties. Returns null if a reader cannot be created.
 	 */
+	@Wakeful
 	@Nullable
 	TransportConnectionReader createReader(TransportProperties p);
 
@@ -25,6 +27,7 @@ public interface SimplexPlugin extends Plugin {
 	 * Attempts to create and return a writer for the given transport
 	 * properties. Returns null if a writer cannot be created.
 	 */
+	@Wakeful
 	@Nullable
 	TransportConnectionWriter createWriter(TransportProperties p);
 }

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

@@ -12,6 +12,11 @@ public interface TransportPropertyConstants {
 	 */
 	int MAX_PROPERTY_LENGTH = 100;
 
+	/**
+	 * Prefix for keys that represent reflected properties.
+	 */
+	String REFLECTED_PROPERTY_PREFIX = "u:";
+
 	/**
 	 * Message metadata key for the transport ID of a local or remote update,
 	 * as a BDF string.

bramble-api/src/main/java/org/briarproject/bramble/api/properties/event/RemoteTransportPropertiesUpdatedEvent.java

@@ -0,0 +1,27 @@
+package org.briarproject.bramble.api.properties.event;
+
+import org.briarproject.bramble.api.event.Event;
+import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
+import org.briarproject.bramble.api.plugin.TransportId;
+import org.briarproject.bramble.api.properties.TransportProperties;
+
+import javax.annotation.concurrent.Immutable;
+
+/**
+ * An event that is broadcast when {@link TransportProperties} are received
+ * from a contact.
+ */
+@Immutable
+@NotNullByDefault
+public class RemoteTransportPropertiesUpdatedEvent extends Event {
+
+	private final TransportId transportId;
+
+	public RemoteTransportPropertiesUpdatedEvent(TransportId transportId) {
+		this.transportId = transportId;
+	}
+
+	public TransportId getTransportId() {
+		return transportId;
+	}
+}

bramble-api/src/main/java/org/briarproject/bramble/api/system/TaskScheduler.java

@@ -0,0 +1,43 @@
+package org.briarproject.bramble.api.system;
+
+import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
+
+import java.util.concurrent.Executor;
+import java.util.concurrent.TimeUnit;
+
+/**
+ * A service that can be used to schedule the execution of tasks.
+ */
+@NotNullByDefault
+public interface TaskScheduler {
+
+	/**
+	 * Submits the given task to the given executor after the given delay.
+	 * <p>
+	 * If the platform supports wake locks, a wake lock will be held while
+	 * submitting and running the task.
+	 */
+	Cancellable schedule(Runnable task, Executor executor, long delay,
+			TimeUnit unit);
+
+	/**
+	 * Submits the given task to the given executor after the given delay,
+	 * and then repeatedly with the given interval between executions
+	 * (measured from the end of one execution to the beginning of the next).
+	 * <p>
+	 * If the platform supports wake locks, a wake lock will be held while
+	 * submitting and running the task.
+	 */
+	Cancellable scheduleWithFixedDelay(Runnable task, Executor executor,
+			long delay, long interval, TimeUnit unit);
+
+	interface Cancellable {
+
+		/**
+		 * Cancels the task if it has not already started running. If the task
+		 * is {@link #scheduleWithFixedDelay(Runnable, Executor, long, long, TimeUnit) periodic},
+		 * all future executions of the task are cancelled.
+		 */
+		void cancel();
+	}
+}

bramble-api/src/main/java/org/briarproject/bramble/api/system/Wakeful.java

@@ -0,0 +1,19 @@
+package org.briarproject.bramble.api.system;
+
+import java.lang.annotation.Retention;
+import java.lang.annotation.Target;
+
+import javax.inject.Qualifier;
+
+import static java.lang.annotation.ElementType.METHOD;
+import static java.lang.annotation.RetentionPolicy.RUNTIME;
+
+/**
+ * Annotation for methods that must be called while holding a wake lock, if
+ * the platform supports wake locks.
+ */
+@Qualifier
+@Target(METHOD)
+@Retention(RUNTIME)
+public @interface Wakeful {
+}

bramble-api/src/main/java/org/briarproject/bramble/api/system/WakefulIoExecutor.java

@@ -0,0 +1,26 @@
+package org.briarproject.bramble.api.system;
+
+import java.lang.annotation.Retention;
+import java.lang.annotation.Target;
+
+import javax.inject.Qualifier;
+
+import static java.lang.annotation.ElementType.FIELD;
+import static java.lang.annotation.ElementType.METHOD;
+import static java.lang.annotation.ElementType.PARAMETER;
+import static java.lang.annotation.RetentionPolicy.RUNTIME;
+
+/**
+ * Annotation for injecting the executor for long-running IO tasks that should
+ * run without sleeping. Also used for annotating methods that should run on
+ * this executor.
+ * <p>
+ * The contract of this executor is that tasks may be run concurrently, and
+ * submitting a task will never block. Tasks must not run indefinitely. Tasks
+ * submitted during shutdown are discarded.
+ */
+@Qualifier
+@Target({FIELD, METHOD, PARAMETER})
+@Retention(RUNTIME)
+public @interface WakefulIoExecutor {
+}

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

@@ -2,13 +2,17 @@ package org.briarproject.bramble.util;
 
 import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
 
-import java.net.Inet6Address;
+import java.net.Inet4Address;
 import java.net.InetAddress;
 import java.net.InetSocketAddress;
 import java.net.SocketAddress;
 
 import javax.annotation.Nullable;
 
+import static org.briarproject.bramble.util.StringUtils.isNullOrEmpty;
+import static org.briarproject.bramble.util.StringUtils.isValidMac;
+import static org.briarproject.bramble.util.StringUtils.toHexString;
+
 @NotNullByDefault
 public class PrivacyUtils {
 
@@ -19,7 +23,7 @@ public class PrivacyUtils {
 
 	@Nullable
 	public static String scrubMacAddress(@Nullable String address) {
-		if (address == null || address.length() == 0) return null;
+		if (isNullOrEmpty(address) || !isValidMac(address)) return address;
 		// this is a fake address we need to know about
 		if (address.equals("02:00:00:00:00:00")) return address;
 		// keep first and last octet of MAC address
@@ -27,39 +31,37 @@ public class PrivacyUtils {
 				+ address.substring(14, 17);
 	}
 
-	@Nullable
 	public static String scrubInetAddress(InetAddress address) {
-		// don't scrub link and site local addresses
+		if (address instanceof Inet4Address) {
-		if (address.isLinkLocalAddress() || address.isSiteLocalAddress())
+			// Don't scrub local IPv4 addresses
-			return address.toString();
+			if (address.isLoopbackAddress() || address.isLinkLocalAddress() ||
-		// completely scrub IPv6 addresses
+					address.isSiteLocalAddress()) {
-		if (address instanceof Inet6Address) return "[scrubbed]";
+				return address.getHostAddress();
-		// keep first and last octet of IPv4 addresses
+			}
-		return scrubInetAddress(address.toString());
+			// Keep first and last octet of non-local IPv4 addresses
+			return scrubIpv4Address(address.getAddress());
+		} else {
+			// Keep first and last octet of IPv6 addresses
+			return scrubIpv6Address(address.getAddress());
+		}
 	}
 
-	@Nullable
+	private static String scrubIpv4Address(byte[] ipv4) {
-	public static String scrubInetAddress(@Nullable String address) {
+		return (ipv4[0] & 0xFF) + ".[scrubbed]." + (ipv4[3] & 0xFF);
-		if (address == null) return null;
+	}
-
+
-		int firstDot = address.indexOf(".");
+	private static String scrubIpv6Address(byte[] ipv6) {
-		if (firstDot == -1) return "[scrubbed]";
+		String hex = toHexString(ipv6).toLowerCase();
-		String prefix = address.substring(0, firstDot + 1);
+		return hex.substring(0, 2) + "[scrubbed]" + hex.substring(30);
-		int lastDot = address.lastIndexOf(".");
-		String suffix = address.substring(lastDot, address.length());
-		return prefix + "[scrubbed]" + suffix;
 	}
 
-	@Nullable
 	public static String scrubSocketAddress(InetSocketAddress address) {
-		InetAddress inetAddress = address.getAddress();
+		return scrubInetAddress(address.getAddress());
-		return scrubInetAddress(inetAddress);
 	}
 
-	@Nullable
 	public static String scrubSocketAddress(SocketAddress address) {
 		if (address instanceof InetSocketAddress)
 			return scrubSocketAddress((InetSocketAddress) address);
-		return scrubInetAddress(address.toString());
+		return "[scrubbed]";
 	}
 }

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

@@ -9,7 +9,6 @@ import org.briarproject.bramble.plugin.PluginModule;
 import org.briarproject.bramble.properties.PropertiesModule;
 import org.briarproject.bramble.rendezvous.RendezvousModule;
 import org.briarproject.bramble.sync.validation.ValidationModule;
-import org.briarproject.bramble.system.SystemModule;
 import org.briarproject.bramble.transport.TransportModule;
 import org.briarproject.bramble.versioning.VersioningModule;
 
@@ -31,8 +30,6 @@ public interface BrambleCoreEagerSingletons {
 
 	void inject(RendezvousModule.EagerSingletons init);
 
-	void inject(SystemModule.EagerSingletons init);
-
 	void inject(TransportModule.EagerSingletons init);
 
 	void inject(ValidationModule.EagerSingletons init);
@@ -50,7 +47,6 @@ public interface BrambleCoreEagerSingletons {
 			c.inject(new RendezvousModule.EagerSingletons());
 			c.inject(new PluginModule.EagerSingletons());
 			c.inject(new PropertiesModule.EagerSingletons());
-			c.inject(new SystemModule.EagerSingletons());
 			c.inject(new TransportModule.EagerSingletons());
 			c.inject(new ValidationModule.EagerSingletons());
 			c.inject(new VersioningModule.EagerSingletons());

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

@@ -21,7 +21,7 @@ import org.briarproject.bramble.rendezvous.RendezvousModule;
 import org.briarproject.bramble.settings.SettingsModule;
 import org.briarproject.bramble.sync.SyncModule;
 import org.briarproject.bramble.sync.validation.ValidationModule;
-import org.briarproject.bramble.system.SystemModule;
+import org.briarproject.bramble.system.ClockModule;
 import org.briarproject.bramble.transport.TransportModule;
 import org.briarproject.bramble.versioning.VersioningModule;
 
@@ -29,6 +29,7 @@ import dagger.Module;
 
 @Module(includes = {
 		ClientModule.class,
+		ClockModule.class,
 		ConnectionModule.class,
 		ContactModule.class,
 		CryptoModule.class,
@@ -48,7 +49,6 @@ import dagger.Module;
 		RendezvousModule.class,
 		SettingsModule.class,
 		SyncModule.class,
-		SystemModule.class,
 		TransportModule.class,
 		ValidationModule.class,
 		VersioningModule.class

bramble-core/src/main/java/org/briarproject/bramble/connection/ConnectionRegistryImpl.java

@@ -63,18 +63,12 @@ class ConnectionRegistryImpl implements ConnectionRegistry {
 	@Override
 	public void registerIncomingConnection(ContactId c, TransportId t,
 			InterruptibleConnection conn) {
-		if (LOG.isLoggable(INFO)) {
-			LOG.info("Incoming connection registered: " + t);
-		}
 		registerConnection(c, t, conn, true);
 	}
 
 	@Override
 	public void registerOutgoingConnection(ContactId c, TransportId t,
 			InterruptibleConnection conn, Priority priority) {
-		if (LOG.isLoggable(INFO)) {
-			LOG.info("Outgoing connection registered: " + t);
-		}
 		registerConnection(c, t, conn, false);
 		setPriority(c, t, conn, priority);
 	}

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

@@ -3,15 +3,15 @@ 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 org.briarproject.bramble.api.system.TaskScheduler;
+import org.briarproject.bramble.api.system.TaskScheduler.Cancellable;
+import org.briarproject.bramble.api.system.Wakeful;
 
 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;
@@ -30,7 +30,7 @@ class TimeoutMonitorImpl implements TimeoutMonitor {
 
 	private static final long CHECK_INTERVAL_MS = SECONDS.toMillis(10);
 
-	private final ScheduledExecutorService scheduler;
+	private final TaskScheduler scheduler;
 	private final Executor ioExecutor;
 	private final Clock clock;
 	private final Object lock = new Object();
@@ -38,10 +38,10 @@ class TimeoutMonitorImpl implements TimeoutMonitor {
 	private final List<TimeoutInputStream> streams = new ArrayList<>();
 
 	@GuardedBy("lock")
-	private Future<?> task = null;
+	private Cancellable cancellable = null;
 
 	@Inject
-	TimeoutMonitorImpl(@Scheduler ScheduledExecutorService scheduler,
+	TimeoutMonitorImpl(TaskScheduler scheduler,
 			@IoExecutor Executor ioExecutor, Clock clock) {
 		this.scheduler = scheduler;
 		this.ioExecutor = ioExecutor;
@@ -55,8 +55,9 @@ class TimeoutMonitorImpl implements TimeoutMonitor {
 				timeoutMs, this::removeStream);
 		synchronized (lock) {
 			if (streams.isEmpty()) {
-				task = scheduler.scheduleWithFixedDelay(this::checkTimeouts,
+				cancellable = scheduler.scheduleWithFixedDelay(
-						CHECK_INTERVAL_MS, CHECK_INTERVAL_MS, MILLISECONDS);
+						this::checkTimeouts, ioExecutor, CHECK_INTERVAL_MS,
+						CHECK_INTERVAL_MS, MILLISECONDS);
 			}
 			streams.add(stream);
 		}
@@ -64,33 +65,35 @@ class TimeoutMonitorImpl implements TimeoutMonitor {
 	}
 
 	private void removeStream(TimeoutInputStream stream) {
-		Future<?> toCancel = null;
+		Cancellable toCancel = null;
 		synchronized (lock) {
 			if (streams.remove(stream) && streams.isEmpty()) {
-				toCancel = task;
+				toCancel = cancellable;
-				task = null;
+				cancellable = null;
 			}
 		}
-		if (toCancel != null) toCancel.cancel(false);
+		if (toCancel != null) {
+			LOG.info("Cancelling timeout monitor task");
+			toCancel.cancel();
+		}
 	}
 
-	@Scheduler
+	@IoExecutor
+	@Wakeful
 	private void checkTimeouts() {
-		ioExecutor.execute(() -> {
+		List<TimeoutInputStream> snapshot;
-			List<TimeoutInputStream> snapshot;
+		synchronized (lock) {
-			synchronized (lock) {
+			snapshot = new ArrayList<>(streams);
-				snapshot = new ArrayList<>(streams);
+		}
-			}
+		for (TimeoutInputStream stream : snapshot) {
-			for (TimeoutInputStream stream : snapshot) {
+			if (stream.hasTimedOut()) {
-				if (stream.hasTimedOut()) {
+				LOG.info("Input stream has timed out");
-					LOG.info("Input stream has timed out");
+				try {
-					try {
+					stream.close();
-						stream.close();
+				} catch (IOException e) {
-					} catch (IOException e) {
+					logException(LOG, INFO, e);
-						logException(LOG, INFO, e);
-					}
 				}
 			}
-		});
+		}
 	}
 }

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

@@ -1,6 +1,7 @@
 package org.briarproject.bramble.plugin;
 
 import org.briarproject.bramble.api.connection.ConnectionManager;
+import org.briarproject.bramble.api.contact.ContactId;
 import org.briarproject.bramble.api.db.DbException;
 import org.briarproject.bramble.api.event.EventBus;
 import org.briarproject.bramble.api.lifecycle.IoExecutor;
@@ -8,6 +9,7 @@ import org.briarproject.bramble.api.lifecycle.Service;
 import org.briarproject.bramble.api.lifecycle.ServiceException;
 import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
 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;
@@ -18,14 +20,16 @@ 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.TransportDisabledEvent;
+import org.briarproject.bramble.api.plugin.event.TransportActiveEvent;
-import org.briarproject.bramble.api.plugin.event.TransportEnabledEvent;
+import org.briarproject.bramble.api.plugin.event.TransportInactiveEvent;
+import org.briarproject.bramble.api.plugin.event.TransportStateEvent;
 import org.briarproject.bramble.api.plugin.simplex.SimplexPlugin;
 import org.briarproject.bramble.api.plugin.simplex.SimplexPluginFactory;
 import org.briarproject.bramble.api.properties.TransportProperties;
 import org.briarproject.bramble.api.properties.TransportPropertyManager;
 import org.briarproject.bramble.api.settings.Settings;
 import org.briarproject.bramble.api.settings.SettingsManager;
+import org.briarproject.bramble.api.system.WakefulIoExecutor;
 
 import java.util.ArrayList;
 import java.util.Collection;
@@ -36,15 +40,21 @@ 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;
 import javax.inject.Inject;
 
+import static java.util.Collections.emptyList;
 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.api.plugin.Plugin.State.STARTING_STOPPING;
 import static org.briarproject.bramble.util.LogUtils.logDuration;
 import static org.briarproject.bramble.util.LogUtils.logException;
 import static org.briarproject.bramble.util.LogUtils.now;
@@ -56,7 +66,7 @@ class PluginManagerImpl implements PluginManager, Service {
 	private static final Logger LOG =
 			getLogger(PluginManagerImpl.class.getName());
 
-	private final Executor ioExecutor;
+	private final Executor ioExecutor, wakefulIoExecutor;
 	private final EventBus eventBus;
 	private final PluginConfig pluginConfig;
 	private final ConnectionManager connectionManager;
@@ -69,11 +79,15 @@ class PluginManagerImpl implements PluginManager, Service {
 	private final AtomicBoolean used = new AtomicBoolean(false);
 
 	@Inject
-	PluginManagerImpl(@IoExecutor Executor ioExecutor, EventBus eventBus,
+	PluginManagerImpl(@IoExecutor Executor ioExecutor,
-			PluginConfig pluginConfig, ConnectionManager connectionManager,
+			@WakefulIoExecutor Executor wakefulIoExecutor,
+			EventBus eventBus,
+			PluginConfig pluginConfig,
+			ConnectionManager connectionManager,
 			SettingsManager settingsManager,
 			TransportPropertyManager transportPropertyManager) {
 		this.ioExecutor = ioExecutor;
+		this.wakefulIoExecutor = wakefulIoExecutor;
 		this.eventBus = eventBus;
 		this.pluginConfig = pluginConfig;
 		this.connectionManager = connectionManager;
@@ -101,7 +115,7 @@ class PluginManagerImpl implements PluginManager, Service {
 				simplexPlugins.add(s);
 				CountDownLatch startLatch = new CountDownLatch(1);
 				startLatches.put(t, startLatch);
-				ioExecutor.execute(new PluginStarter(s, startLatch));
+				wakefulIoExecutor.execute(new PluginStarter(s, startLatch));
 			}
 		}
 		// Instantiate the duplex plugins and start them asynchronously
@@ -117,7 +131,7 @@ class PluginManagerImpl implements PluginManager, Service {
 				duplexPlugins.add(d);
 				CountDownLatch startLatch = new CountDownLatch(1);
 				startLatches.put(t, startLatch);
-				ioExecutor.execute(new PluginStarter(d, startLatch));
+				wakefulIoExecutor.execute(new PluginStarter(d, startLatch));
 			}
 		}
 	}
@@ -129,12 +143,16 @@ class PluginManagerImpl implements PluginManager, Service {
 		LOG.info("Stopping simplex plugins");
 		for (SimplexPlugin s : simplexPlugins) {
 			CountDownLatch startLatch = startLatches.get(s.getId());
+			// Don't need the wakeful executor here as we wait for the plugin
+			// to stop before returning
 			ioExecutor.execute(new PluginStopper(s, startLatch, stopLatch));
 		}
 		// Stop the duplex plugins
 		LOG.info("Stopping duplex plugins");
 		for (DuplexPlugin d : duplexPlugins) {
 			CountDownLatch startLatch = startLatches.get(d.getId());
+			// Don't need the wakeful executor here as we wait for the plugin
+			// to stop before returning
 			ioExecutor.execute(new PluginStopper(d, startLatch, stopLatch));
 		}
 		// Wait for all the plugins to stop
@@ -177,7 +195,27 @@ class PluginManagerImpl implements PluginManager, Service {
 		return supported;
 	}
 
-	private class PluginStarter implements Runnable {
+	@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 static class PluginStarter implements Runnable {
 
 		private final Plugin plugin;
 		private final CountDownLatch startLatch;
@@ -207,7 +245,7 @@ class PluginManagerImpl implements PluginManager, Service {
 		}
 	}
 
-	private class PluginStopper implements Runnable {
+	private static class PluginStopper implements Runnable {
 
 		private final Plugin plugin;
 		private final CountDownLatch startLatch, stopLatch;
@@ -250,7 +288,8 @@ class PluginManagerImpl implements PluginManager, Service {
 	private class Callback implements PluginCallback {
 
 		private final TransportId id;
-		private final AtomicBoolean enabled = new AtomicBoolean(false);
+		private final AtomicReference<State> state =
+				new AtomicReference<>(STARTING_STOPPING);
 
 		private Callback(TransportId id) {
 			this.id = id;
@@ -277,14 +316,22 @@ class PluginManagerImpl implements PluginManager, Service {
 		}
 
 		@Override
-		public void mergeSettings(Settings s) {
+		public Collection<TransportProperties> getRemoteProperties() {
 			try {
-				settingsManager.mergeSettings(s, id.getString());
+				Map<ContactId, TransportProperties> remote =
+						transportPropertyManager.getRemoteProperties(id);
+				return remote.values();
 			} catch (DbException e) {
 				logException(LOG, WARNING, e);
+				return emptyList();
 			}
 		}
 
+		@Override
+		public void mergeSettings(Settings s) {
+			PluginManagerImpl.this.mergeSettings(s, id.getString());
+		}
+
 		@Override
 		public void mergeLocalProperties(TransportProperties p) {
 			try {
@@ -295,15 +342,24 @@ class PluginManagerImpl implements PluginManager, Service {
 		}
 
 		@Override
-		public void transportEnabled() {
+		public void pluginStateChanged(State newState) {
-			if (!enabled.getAndSet(true))
+			State oldState = state.getAndSet(newState);
-				eventBus.broadcast(new TransportEnabledEvent(id));
+			if (newState != oldState) {
-		}
+				if (LOG.isLoggable(INFO)) {
-
+					LOG.info(id + " changed from state " + oldState
-		@Override
+							+ " to " + newState);
-		public void transportDisabled() {
+				}
-			if (enabled.getAndSet(false))
+				eventBus.broadcast(new TransportStateEvent(id, newState));
-				eventBus.broadcast(new TransportDisabledEvent(id));
+				if (newState == ACTIVE) {
+					eventBus.broadcast(new TransportActiveEvent(id));
+				} else if (oldState == ACTIVE) {
+					eventBus.broadcast(new TransportInactiveEvent(id));
+				}
+			} else if (newState == DISABLED) {
+				// Broadcast an event even though the state hasn't changed, as
+				// the reasons for the plugin being disabled may have changed
+				eventBus.broadcast(new TransportStateEvent(id, newState));
+			}
 		}
 
 		@Override

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

@@ -20,13 +20,16 @@ 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.TransportDisabledEvent;
+import org.briarproject.bramble.api.plugin.event.TransportActiveEvent;
-import org.briarproject.bramble.api.plugin.event.TransportEnabledEvent;
+import org.briarproject.bramble.api.plugin.event.TransportInactiveEvent;
 import org.briarproject.bramble.api.plugin.simplex.SimplexPlugin;
 import org.briarproject.bramble.api.properties.TransportProperties;
 import org.briarproject.bramble.api.properties.TransportPropertyManager;
 import org.briarproject.bramble.api.system.Clock;
-import org.briarproject.bramble.api.system.Scheduler;
+import org.briarproject.bramble.api.system.TaskScheduler;
+import org.briarproject.bramble.api.system.TaskScheduler.Cancellable;
+import org.briarproject.bramble.api.system.Wakeful;
+import org.briarproject.bramble.api.system.WakefulIoExecutor;
 
 import java.security.SecureRandom;
 import java.util.ArrayList;
@@ -35,8 +38,6 @@ import java.util.HashMap;
 import java.util.Map;
 import java.util.Map.Entry;
 import java.util.concurrent.Executor;
-import java.util.concurrent.Future;
-import java.util.concurrent.ScheduledExecutorService;
 import java.util.concurrent.locks.Lock;
 import java.util.concurrent.locks.ReentrantLock;
 import java.util.logging.Logger;
@@ -57,8 +58,8 @@ class PollerImpl implements Poller, EventListener {
 
 	private static final Logger LOG = getLogger(PollerImpl.class.getName());
 
-	private final Executor ioExecutor;
+	private final Executor ioExecutor, wakefulIoExecutor;
-	private final ScheduledExecutorService scheduler;
+	private final TaskScheduler scheduler;
 	private final ConnectionManager connectionManager;
 	private final ConnectionRegistry connectionRegistry;
 	private final PluginManager pluginManager;
@@ -71,12 +72,16 @@ class PollerImpl implements Poller, EventListener {
 
 	@Inject
 	PollerImpl(@IoExecutor Executor ioExecutor,
-			@Scheduler ScheduledExecutorService scheduler,
+			@WakefulIoExecutor Executor wakefulIoExecutor,
+			TaskScheduler scheduler,
 			ConnectionManager connectionManager,
-			ConnectionRegistry connectionRegistry, PluginManager pluginManager,
+			ConnectionRegistry connectionRegistry,
+			PluginManager pluginManager,
 			TransportPropertyManager transportPropertyManager,
-			SecureRandom random, Clock clock) {
+			SecureRandom random,
+			Clock clock) {
 		this.ioExecutor = ioExecutor;
+		this.wakefulIoExecutor = wakefulIoExecutor;
 		this.scheduler = scheduler;
 		this.connectionManager = connectionManager;
 		this.connectionRegistry = connectionRegistry;
@@ -106,13 +111,13 @@ class PollerImpl implements Poller, EventListener {
 			ConnectionOpenedEvent c = (ConnectionOpenedEvent) e;
 			// Reschedule polling, the polling interval may have decreased
 			reschedule(c.getTransportId());
-		} else if (e instanceof TransportEnabledEvent) {
+		} else if (e instanceof TransportActiveEvent) {
-			TransportEnabledEvent t = (TransportEnabledEvent) e;
+			TransportActiveEvent t = (TransportActiveEvent) e;
-			// Poll the newly enabled transport
+			// Poll the newly activated transport
 			pollNow(t.getTransportId());
-		} else if (e instanceof TransportDisabledEvent) {
+		} else if (e instanceof TransportInactiveEvent) {
-			TransportDisabledEvent t = (TransportDisabledEvent) e;
+			TransportInactiveEvent t = (TransportInactiveEvent) e;
-			// Cancel polling for the disabled transport
+			// Cancel polling for the deactivated transport
 			cancel(t.getTransportId());
 		}
 	}
@@ -133,7 +138,7 @@ class PollerImpl implements Poller, EventListener {
 	}
 
 	private void connectToContact(ContactId c, SimplexPlugin p) {
-		ioExecutor.execute(() -> {
+		wakefulIoExecutor.execute(() -> {
 			TransportId t = p.getId();
 			if (connectionRegistry.isConnected(c, t)) return;
 			try {
@@ -149,7 +154,7 @@ class PollerImpl implements Poller, EventListener {
 	}
 
 	private void connectToContact(ContactId c, DuplexPlugin p) {
-		ioExecutor.execute(() -> {
+		wakefulIoExecutor.execute(() -> {
 			TransportId t = p.getId();
 			if (connectionRegistry.isConnected(c, t)) return;
 			try {
@@ -186,11 +191,11 @@ class PollerImpl implements Poller, EventListener {
 			if (scheduled == null || due < scheduled.task.due) {
 				// If a later task exists, cancel it. If it's already started
 				// it will abort safely when it finds it's been replaced
-				if (scheduled != null) scheduled.future.cancel(false);
+				if (scheduled != null) scheduled.cancellable.cancel();
 				PollTask task = new PollTask(p, due, randomiseNext);
-				Future future = scheduler.schedule(() ->
+				Cancellable cancellable = scheduler.schedule(task, ioExecutor,
-						ioExecutor.execute(task), delay, MILLISECONDS);
+						delay, MILLISECONDS);
-				tasks.put(t, new ScheduledPollTask(task, future));
+				tasks.put(t, new ScheduledPollTask(task, cancellable));
 			}
 		} finally {
 			lock.unlock();
@@ -201,7 +206,7 @@ class PollerImpl implements Poller, EventListener {
 		lock.lock();
 		try {
 			ScheduledPollTask scheduled = tasks.remove(t);
-			if (scheduled != null) scheduled.future.cancel(false);
+			if (scheduled != null) scheduled.cancellable.cancel();
 		} finally {
 			lock.unlock();
 		}
@@ -232,11 +237,11 @@ class PollerImpl implements Poller, EventListener {
 	private class ScheduledPollTask {
 
 		private final PollTask task;
-		private final Future future;
+		private final Cancellable cancellable;
 
-		private ScheduledPollTask(PollTask task, Future future) {
+		private ScheduledPollTask(PollTask task, Cancellable cancellable) {
 			this.task = task;
-			this.future = future;
+			this.cancellable = cancellable;
 		}
 	}
 
@@ -254,6 +259,7 @@ class PollerImpl implements Poller, EventListener {
 
 		@Override
 		@IoExecutor
+		@Wakeful
 		public void run() {
 			lock.lock();
 			try {

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

@@ -0,0 +1,14 @@
+package org.briarproject.bramble.plugin.bluetooth;
+
+import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
+import org.briarproject.bramble.api.plugin.duplex.DuplexPlugin;
+import org.briarproject.bramble.api.plugin.duplex.DuplexTransportConnection;
+
+import java.io.IOException;
+
+@NotNullByDefault
+interface BluetoothConnectionFactory<S> {
+
+	DuplexTransportConnection wrapSocket(DuplexPlugin plugin, S socket)
+			throws IOException;
+}

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

@@ -3,16 +3,9 @@ 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.SECONDS;
-
 @NotNullByDefault
 interface BluetoothConnectionLimiter {
 
-	/**
-	 * How long a connection must remain open before it's considered stable.
-	 */
-	long STABILITY_PERIOD_MS = SECONDS.toMillis(90);
-
 	/**
 	 * Informs the limiter that key agreement has started.
 	 */

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

@@ -4,9 +4,7 @@ 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.util.Iterator;
 import java.util.LinkedList;
 import java.util.List;
 import java.util.logging.Logger;
@@ -26,19 +24,16 @@ class BluetoothConnectionLimiterImpl implements BluetoothConnectionLimiter {
 			getLogger(BluetoothConnectionLimiterImpl.class.getName());
 
 	private final EventBus eventBus;
-	private final Clock clock;
 
 	private final Object lock = new Object();
 	@GuardedBy("lock")
-	private final List<ConnectionRecord> connections = new LinkedList<>();
+	private final List<DuplexTransportConnection> connections =
+			new LinkedList<>();
 	@GuardedBy("lock")
 	private boolean keyAgreementInProgress = false;
-	@GuardedBy("lock")
-	private int connectionLimit = 2;
 
-	BluetoothConnectionLimiterImpl(EventBus eventBus, Clock clock) {
+	BluetoothConnectionLimiterImpl(EventBus eventBus) {
 		this.eventBus = eventBus;
-		this.clock = clock;
 	}
 
 	@Override
@@ -64,15 +59,9 @@ class BluetoothConnectionLimiterImpl implements BluetoothConnectionLimiter {
 			if (keyAgreementInProgress) {
 				LOG.info("Can't open contact connection during key agreement");
 				return false;
-			}
+			} else {
-			long now = clock.currentTimeMillis();
-			countStableConnections(now);
-			if (connections.size() < connectionLimit) {
 				LOG.info("Can open contact connection");
 				return true;
-			} else {
-				LOG.info("Can't open contact connection due to limit");
-				return false;
 			}
 		}
 	}
@@ -80,9 +69,7 @@ class BluetoothConnectionLimiterImpl implements BluetoothConnectionLimiter {
 	@Override
 	public void connectionOpened(DuplexTransportConnection conn) {
 		synchronized (lock) {
-			long now = clock.currentTimeMillis();
+			connections.add(conn);
-			countStableConnections(now);
-			connections.add(new ConnectionRecord(conn, now));
 			if (LOG.isLoggable(INFO)) {
 				LOG.info("Connection opened, " + connections.size() + " open");
 			}
@@ -92,14 +79,7 @@ class BluetoothConnectionLimiterImpl implements BluetoothConnectionLimiter {
 	@Override
 	public void connectionClosed(DuplexTransportConnection conn) {
 		synchronized (lock) {
-			countStableConnections(clock.currentTimeMillis());
+			connections.remove(conn);
-			Iterator<ConnectionRecord> it = connections.iterator();
-			while (it.hasNext()) {
-				if (it.next().conn == conn) {
-					it.remove();
-					break;
-				}
-			}
 			if (LOG.isLoggable(INFO)) {
 				LOG.info("Connection closed, " + connections.size() + " open");
 			}
@@ -109,36 +89,8 @@ class BluetoothConnectionLimiterImpl implements BluetoothConnectionLimiter {
 	@Override
 	public void allConnectionsClosed() {
 		synchronized (lock) {
-			long now = clock.currentTimeMillis();
-			countStableConnections(now);
 			connections.clear();
 			LOG.info("All connections closed");
 		}
 	}
-
-	@GuardedBy("lock")
-	private void countStableConnections(long now) {
-		int stable = 0;
-		for (ConnectionRecord rec : connections) {
-			if (now - rec.timeOpened >= STABILITY_PERIOD_MS) stable++;
-		}
-		if (stable > connectionLimit) {
-			connectionLimit = stable;
-			if (LOG.isLoggable(INFO)) {
-				LOG.info("Raising connection limit to " + connectionLimit);
-			}
-		}
-	}
-
-	private static class ConnectionRecord {
-
-		private final DuplexTransportConnection conn;
-		private final long timeOpened;
-
-		private ConnectionRecord(DuplexTransportConnection conn,
-				long timeOpened) {
-			this.conn = conn;
-			this.timeOpened = timeOpened;
-		}
-	}
 }

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

@@ -1,16 +1,18 @@
 package org.briarproject.bramble.plugin.bluetooth;
 
 import org.briarproject.bramble.api.FormatException;
+import org.briarproject.bramble.api.Multiset;
 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;
@@ -19,10 +21,8 @@ import org.briarproject.bramble.api.plugin.PluginException;
 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.BluetoothEnabledEvent;
-import org.briarproject.bramble.api.plugin.event.DisableBluetoothEvent;
-import org.briarproject.bramble.api.plugin.event.EnableBluetoothEvent;
 import org.briarproject.bramble.api.properties.TransportProperties;
+import org.briarproject.bramble.api.properties.event.RemoteTransportPropertiesUpdatedEvent;
 import org.briarproject.bramble.api.rendezvous.KeyMaterialSource;
 import org.briarproject.bramble.api.rendezvous.RendezvousEndpoint;
 import org.briarproject.bramble.api.settings.Settings;
@@ -37,16 +37,27 @@ 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.DEFAULT_PREF_ADDRESS_IS_REFLECTED;
+import static org.briarproject.bramble.api.plugin.BluetoothConstants.DEFAULT_PREF_EVER_CONNECTED;
+import static org.briarproject.bramble.api.plugin.BluetoothConstants.DEFAULT_PREF_PLUGIN_ENABLE;
 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.PREF_ADDRESS_IS_REFLECTED;
+import static org.briarproject.bramble.api.plugin.BluetoothConstants.PREF_EVER_CONNECTED;
 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.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.api.plugin.Plugin.State.STARTING_STOPPING;
+import static org.briarproject.bramble.api.properties.TransportPropertyConstants.REFLECTED_PROPERTY_PREFIX;
 import static org.briarproject.bramble.util.LogUtils.logException;
 import static org.briarproject.bramble.util.PrivacyUtils.scrubMacAddress;
 import static org.briarproject.bramble.util.StringUtils.isNullOrEmpty;
@@ -55,35 +66,30 @@ import static org.briarproject.bramble.util.StringUtils.macToString;
 
 @MethodsNotNullByDefault
 @ParametersNotNullByDefault
-abstract class BluetoothPlugin<SS> implements DuplexPlugin, EventListener {
+abstract class BluetoothPlugin<S, SS> implements DuplexPlugin, EventListener {
 
 	private static final Logger LOG =
 			getLogger(BluetoothPlugin.class.getName());
 
 	final BluetoothConnectionLimiter connectionLimiter;
-	final TimeoutMonitor timeoutMonitor;
+	final BluetoothConnectionFactory<S> connectionFactory;
 
-	private final Executor ioExecutor;
+	private final Executor ioExecutor, wakefulIoExecutor;
 	private final SecureRandom secureRandom;
 	private final Backoff backoff;
 	private final PluginCallback callback;
 	private final int maxLatency, maxIdleTime;
 	private final AtomicBoolean used = new AtomicBoolean(false);
+	private final AtomicBoolean everConnected = 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;
 
 	abstract boolean isAdapterEnabled();
 
-	abstract void enableAdapter();
-
-	abstract void disableAdapterIfEnabledByUs();
-
-	abstract void setEnabledByUs();
-
 	/**
 	 * Returns the local Bluetooth address, or null if no valid address can
 	 * be found.
@@ -107,12 +113,18 @@ abstract class BluetoothPlugin<SS> implements DuplexPlugin, EventListener {
 	abstract DuplexTransportConnection discoverAndConnect(String uuid);
 
 	BluetoothPlugin(BluetoothConnectionLimiter connectionLimiter,
-			TimeoutMonitor timeoutMonitor, Executor ioExecutor,
+			BluetoothConnectionFactory<S> connectionFactory,
-			SecureRandom secureRandom, Backoff backoff,
+			Executor ioExecutor,
-			PluginCallback callback, int maxLatency, int maxIdleTime) {
+			Executor wakefulIoExecutor,
+			SecureRandom secureRandom,
+			Backoff backoff,
+			PluginCallback callback,
+			int maxLatency,
+			int maxIdleTime) {
 		this.connectionLimiter = connectionLimiter;
-		this.timeoutMonitor = timeoutMonitor;
+		this.connectionFactory = connectionFactory;
 		this.ioExecutor = ioExecutor;
+		this.wakefulIoExecutor = wakefulIoExecutor;
 		this.secureRandom = secureRandom;
 		this.backoff = backoff;
 		this.callback = callback;
@@ -124,14 +136,18 @@ abstract class BluetoothPlugin<SS> implements DuplexPlugin, EventListener {
 		LOG.info("Bluetooth enabled");
 		// We may not have been able to get the local address before
 		ioExecutor.execute(this::updateProperties);
-		if (shouldAllowContactConnections()) bind();
+		if (getState() == INACTIVE) bind();
 	}
 
 	void onAdapterDisabled() {
 		LOG.info("Bluetooth disabled");
-		tryToClose(socket);
 		connectionLimiter.allConnectionsClosed();
-		callback.transportDisabled();
+		// The server socket may not have been closed automatically
+		SS ss = state.clearServerSocket();
+		if (ss != null) {
+			LOG.info("Closing server socket");
+			tryToClose(ss);
+		}
 	}
 
 	@Override
@@ -152,31 +168,24 @@ abstract class BluetoothPlugin<SS> implements DuplexPlugin, EventListener {
 	@Override
 	public void start() throws PluginException {
 		if (used.getAndSet(true)) throw new IllegalStateException();
+		Settings settings = callback.getSettings();
+		boolean enabledByUser = settings.getBoolean(PREF_PLUGIN_ENABLE,
+				DEFAULT_PREF_PLUGIN_ENABLE);
+		everConnected.set(settings.getBoolean(PREF_EVER_CONNECTED,
+				DEFAULT_PREF_EVER_CONNECTED));
+		state.setStarted(enabledByUser);
 		try {
 			initialiseAdapter();
 		} catch (IOException e) {
 			throw new PluginException(e);
 		}
 		updateProperties();
-		running = true;
+		if (enabledByUser && isAdapterEnabled()) bind();
-		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 (!isRunning() || !shouldAllowContactConnections()) return;
+			if (getState() != INACTIVE) return;
 			// Bind a server socket to accept connections from contacts
 			SS ss;
 			try {
@@ -185,14 +194,13 @@ abstract class BluetoothPlugin<SS> implements DuplexPlugin, EventListener {
 				logException(LOG, WARNING, e);
 				return;
 			}
-			if (!isRunning() || !shouldAllowContactConnections()) {
+			if (!state.setServerSocket(ss)) {
+				LOG.info("Closing redundant server socket");
 				tryToClose(ss);
 				return;
 			}
-			socket = ss;
 			backoff.reset();
-			callback.transportEnabled();
+			acceptContactConnections(ss);
-			acceptContactConnections();
 		});
 	}
 
@@ -200,56 +208,115 @@ abstract class BluetoothPlugin<SS> implements DuplexPlugin, EventListener {
 		TransportProperties p = callback.getLocalProperties();
 		String address = p.get(PROP_ADDRESS);
 		String uuid = p.get(PROP_UUID);
+		Settings s = callback.getSettings();
+		boolean isReflected = s.getBoolean(PREF_ADDRESS_IS_REFLECTED,
+				DEFAULT_PREF_ADDRESS_IS_REFLECTED);
 		boolean changed = false;
-		if (address == null) {
+		if (address == null || isReflected) {
 			address = getBluetoothAddress();
-			if (LOG.isLoggable(INFO))
+			if (LOG.isLoggable(INFO)) {
 				LOG.info("Local address " + scrubMacAddress(address));
-			if (!isNullOrEmpty(address)) {
+			}
-				p.put(PROP_ADDRESS, address);
+			if (address == null) {
+				if (everConnected.get()) {
+					address = getReflectedAddress();
+					if (LOG.isLoggable(INFO)) {
+						LOG.info("Reflected address " +
+								scrubMacAddress(address));
+					}
+					if (address != null) {
+						changed = true;
+						isReflected = true;
+					}
+				}
+			} else {
 				changed = true;
+				isReflected = false;
 			}
 		}
 		if (uuid == null) {
 			byte[] random = new byte[UUID_BYTES];
 			secureRandom.nextBytes(random);
 			uuid = UUID.nameUUIDFromBytes(random).toString();
-			p.put(PROP_UUID, uuid);
 			changed = true;
 		}
 		contactConnectionsUuid = uuid;
-		if (changed) callback.mergeLocalProperties(p);
+		if (changed) {
+			p = new TransportProperties();
+			// If we previously used a reflected address and there's no longer
+			// a reflected address with enough votes to be used, we'll continue
+			// to use the old reflected address until there's a new winner
+			if (address != null) p.put(PROP_ADDRESS, address);
+			p.put(PROP_UUID, uuid);
+			callback.mergeLocalProperties(p);
+			s = new Settings();
+			s.putBoolean(PREF_ADDRESS_IS_REFLECTED, isReflected);
+			callback.mergeSettings(s);
+		}
 	}
 
-	private void acceptContactConnections() {
+	@Nullable
+	private String getReflectedAddress() {
+		// Count the number of votes for each reflected address
+		String key = REFLECTED_PROPERTY_PREFIX + PROP_ADDRESS;
+		Multiset<String> votes = new Multiset<>();
+		for (TransportProperties p : callback.getRemoteProperties()) {
+			String address = p.get(key);
+			if (address != null && isValidAddress(address)) votes.add(address);
+		}
+		// If an address gets more than half of the votes, accept it
+		int total = votes.getTotal();
+		for (String address : votes.keySet()) {
+			if (votes.getCount(address) * 2 > total) return address;
+		}
+		return null;
+	}
+
+	private void acceptContactConnections(SS ss) {
 		while (true) {
 			DuplexTransportConnection conn;
 			try {
-				conn = acceptConnection(socket);
+				conn = acceptConnection(ss);
 			} catch (IOException e) {
-				// This is expected when the socket is closed
+				// This is expected when the server socket is closed
-				if (LOG.isLoggable(INFO)) LOG.info(e.toString());
+				LOG.info("Server socket closed");
+				state.clearServerSocket();
 				return;
 			}
 			LOG.info("Connection received");
 			connectionLimiter.connectionOpened(conn);
 			backoff.reset();
+			setEverConnected();
 			callback.handleConnection(conn);
-			if (!running) return;
+		}
+	}
+
+	private void setEverConnected() {
+		if (!everConnected.getAndSet(true)) {
+			ioExecutor.execute(() -> {
+				Settings s = new Settings();
+				s.putBoolean(PREF_EVER_CONNECTED, true);
+				callback.mergeSettings(s);
+				// Contacts may already have sent a reflected address
+				updateProperties();
+			});
 		}
 	}
 
 	@Override
 	public void stop() {
-		running = false;
+		SS ss = state.setStopped();
-		tryToClose(socket);
+		tryToClose(ss);
-		callback.transportDisabled();
-		disableAdapterIfEnabledByUs();
 	}
 
 	@Override
-	public boolean isRunning() {
+	public State getState() {
-		return running && isAdapterEnabled();
+		return state.getState();
+	}
+
+	@Override
+	public int getReasonsDisabled() {
+		return state.getReasonsDisabled();
 	}
 
 	@Override
@@ -265,7 +332,7 @@ abstract class BluetoothPlugin<SS> implements DuplexPlugin, EventListener {
 	@Override
 	public void poll(Collection<Pair<TransportProperties, ConnectionHandler>>
 			properties) {
-		if (!isRunning() || !shouldAllowContactConnections()) return;
+		if (getState() != ACTIVE) return;
 		backoff.increment();
 		for (Pair<TransportProperties, ConnectionHandler> p : properties) {
 			connect(p.getFirst(), p.getSecond());
@@ -277,10 +344,11 @@ abstract class BluetoothPlugin<SS> implements DuplexPlugin, EventListener {
 		if (isNullOrEmpty(address)) return;
 		String uuid = p.get(PROP_UUID);
 		if (isNullOrEmpty(uuid)) return;
-		ioExecutor.execute(() -> {
+		wakefulIoExecutor.execute(() -> {
 			DuplexTransportConnection d = createConnection(p);
 			if (d != null) {
 				backoff.reset();
+				setEverConnected();
 				h.handleConnection(d);
 			}
 		});
@@ -319,7 +387,7 @@ abstract class BluetoothPlugin<SS> implements DuplexPlugin, EventListener {
 
 	@Override
 	public DuplexTransportConnection createConnection(TransportProperties p) {
-		if (!isRunning() || !shouldAllowContactConnections()) return null;
+		if (getState() != ACTIVE) return null;
 		if (!connectionLimiter.canOpenContactConnection()) return null;
 		String address = p.get(PROP_ADDRESS);
 		if (isNullOrEmpty(address)) return null;
@@ -337,7 +405,7 @@ abstract class BluetoothPlugin<SS> implements DuplexPlugin, EventListener {
 
 	@Override
 	public KeyAgreementListener createKeyAgreementListener(byte[] commitment) {
-		if (!isRunning()) return null;
+		if (getState() != ACTIVE) 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);
@@ -349,7 +417,7 @@ abstract class BluetoothPlugin<SS> implements DuplexPlugin, EventListener {
 			logException(LOG, WARNING, e);
 			return null;
 		}
-		if (!isRunning()) {
+		if (getState() != ACTIVE) {
 			tryToClose(ss);
 			return null;
 		}
@@ -363,7 +431,7 @@ abstract class BluetoothPlugin<SS> implements DuplexPlugin, EventListener {
 	@Override
 	public DuplexTransportConnection createKeyAgreementConnection(
 			byte[] commitment, BdfList descriptor) {
-		if (!isRunning()) return null;
+		if (getState() != ACTIVE) return null;
 		// No truncation necessary because COMMIT_LENGTH = 16
 		String uuid = UUID.nameUUIDFromBytes(commitment).toString();
 		DuplexTransportConnection conn;
@@ -383,7 +451,10 @@ abstract class BluetoothPlugin<SS> implements DuplexPlugin, EventListener {
 				LOG.info("Connecting to key agreement UUID " + uuid);
 			conn = connect(address, uuid);
 		}
-		if (conn != null) connectionLimiter.connectionOpened(conn);
+		if (conn != null) {
+			connectionLimiter.connectionOpened(conn);
+			setEverConnected();
+		}
 		return conn;
 	}
 
@@ -406,13 +477,7 @@ abstract class BluetoothPlugin<SS> implements DuplexPlugin, EventListener {
 
 	@Override
 	public void eventOccurred(Event e) {
-		if (e instanceof EnableBluetoothEvent) {
+		if (e instanceof SettingsUpdatedEvent) {
-			ioExecutor.execute(this::enableAdapter);
-		} else if (e instanceof DisableBluetoothEvent) {
-			ioExecutor.execute(this::disableAdapterIfEnabledByUs);
-		} else if (e instanceof BluetoothEnabledEvent) {
-			setEnabledByUs();
-		} else if (e instanceof SettingsUpdatedEvent) {
 			SettingsUpdatedEvent s = (SettingsUpdatedEvent) e;
 			if (s.getNamespace().equals(ID.getString()))
 				ioExecutor.execute(() -> onSettingsUpdated(s.getSettings()));
@@ -420,22 +485,31 @@ abstract class BluetoothPlugin<SS> implements DuplexPlugin, EventListener {
 			ioExecutor.execute(connectionLimiter::keyAgreementStarted);
 		} else if (e instanceof KeyAgreementStoppedListeningEvent) {
 			ioExecutor.execute(connectionLimiter::keyAgreementEnded);
+		} else if (e instanceof RemoteTransportPropertiesUpdatedEvent) {
+			RemoteTransportPropertiesUpdatedEvent r =
+					(RemoteTransportPropertiesUpdatedEvent) e;
+			if (r.getTransportId().equals(ID)) {
+				ioExecutor.execute(this::updateProperties);
+			}
 		}
 	}
 
+	@IoExecutor
 	private void onSettingsUpdated(Settings settings) {
-		boolean wasAllowed = shouldAllowContactConnections();
+		boolean enabledByUser = settings.getBoolean(PREF_PLUGIN_ENABLE,
-		loadSettings(settings);
+				DEFAULT_PREF_PLUGIN_ENABLE);
-		boolean isAllowed = shouldAllowContactConnections();
+		SS ss = state.setEnabledByUser(enabledByUser);
-		if (wasAllowed && !isAllowed) {
+		State s = getState();
-			LOG.info("Contact connections disabled");
+		if (ss != null) {
-			tryToClose(socket);
+			LOG.info("Disabled by user, closing server socket");
-			callback.transportDisabled();
+			tryToClose(ss);
-			disableAdapterIfEnabledByUs();
+		} else if (s == INACTIVE) {
-		} else if (!wasAllowed && isAllowed) {
+			if (isAdapterEnabled()) {
-			LOG.info("Contact connections enabled");
+				LOG.info("Enabled by user, opening server socket");
-			if (isAdapterEnabled()) bind();
+				bind();
-			else enableAdapter();
+			} else {
+				LOG.info("Enabled by user but adapter is disabled");
+			}
 		}
 	}
 
@@ -461,4 +535,70 @@ abstract class BluetoothPlugin<SS> implements DuplexPlugin, EventListener {
 			tryToClose(ss);
 		}
 	}
+
+	@ThreadSafe
+	@NotNullByDefault
+	protected class PluginState {
+
+		@GuardedBy("this")
+		private boolean started = false,
+				stopped = 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;
+		}
+
+		@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) return STARTING_STOPPING;
+			if (!enabledByUser) return DISABLED;
+			return serverSocket == null ? INACTIVE : ACTIVE;
+		}
+
+		synchronized int getReasonsDisabled() {
+			return getState() == DISABLED ? REASON_USER : 0;
+		}
+	}
 }

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

@@ -16,6 +16,7 @@ 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;
 
@@ -45,7 +46,7 @@ abstract class FilePlugin implements SimplexPlugin {
 
 	@Override
 	public TransportConnectionReader createReader(TransportProperties p) {
-		if (!isRunning()) return null;
+		if (getState() != ACTIVE) return null;
 		String path = p.get(PROP_PATH);
 		if (isNullOrEmpty(path)) return null;
 		try {
@@ -60,7 +61,7 @@ abstract class FilePlugin implements SimplexPlugin {
 
 	@Override
 	public TransportConnectionWriter createWriter(TransportProperties p) {
-		if (!isRunning()) return null;
+		if (getState() != ACTIVE) 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

@@ -11,10 +11,10 @@ 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.Inet6Address;
 import java.net.InetAddress;
 import java.net.InetSocketAddress;
 import java.net.InterfaceAddress;
@@ -22,8 +22,9 @@ import java.net.ServerSocket;
 import java.net.Socket;
 import java.net.UnknownHostException;
 import java.util.ArrayList;
+import java.util.Deque;
+import java.util.LinkedList;
 import java.util.List;
-import java.util.Random;
 import java.util.concurrent.Executor;
 import java.util.logging.Logger;
 
@@ -31,38 +32,49 @@ 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;
 import static java.util.logging.Logger.getLogger;
 import static org.briarproject.bramble.api.keyagreement.KeyAgreementConstants.TRANSPORT_ID_LAN;
+import static org.briarproject.bramble.api.plugin.LanTcpConstants.DEFAULT_PREF_PLUGIN_ENABLE;
 import static org.briarproject.bramble.api.plugin.LanTcpConstants.ID;
+import static org.briarproject.bramble.api.plugin.LanTcpConstants.PREF_IPV6;
 import static org.briarproject.bramble.api.plugin.LanTcpConstants.PREF_LAN_IP_PORTS;
+import static org.briarproject.bramble.api.plugin.LanTcpConstants.PROP_IPV6;
 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.api.properties.TransportPropertyConstants.MAX_PROPERTY_LENGTH;
 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.fromHexString;
 import static org.briarproject.bramble.util.StringUtils.isNullOrEmpty;
 import static org.briarproject.bramble.util.StringUtils.join;
+import static org.briarproject.bramble.util.StringUtils.toHexString;
+import static org.briarproject.bramble.util.StringUtils.utf8IsTooLong;
 
 @NotNullByDefault
 class LanTcpPlugin extends TcpPlugin {
 
 	private static final Logger LOG = getLogger(LanTcpPlugin.class.getName());
 
-	private static final int MAX_ADDRESSES = 4;
 	private static final String SEPARATOR = ",";
 
 	/**
 	 * The IP address of an Android device providing a wifi access point.
+	 * <p>
+	 * Most devices use this address, but at least one device (Honor 8A) may
+	 * use other addresses in the range 192.168.43.0/24.
 	 */
-	protected static final InetAddress WIFI_AP_ADDRESS;
+	private 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;
+	private static final InetAddress WIFI_DIRECT_AP_ADDRESS;
 
 	static {
 		try {
@@ -76,10 +88,15 @@ class LanTcpPlugin extends TcpPlugin {
 		}
 	}
 
-	LanTcpPlugin(Executor ioExecutor, Backoff backoff, PluginCallback callback,
+	LanTcpPlugin(Executor ioExecutor,
-			int maxLatency, int maxIdleTime, int connectionTimeout) {
+			Executor wakefulIoExecutor,
-		super(ioExecutor, backoff, callback, maxLatency, maxIdleTime,
+			Backoff backoff,
-				connectionTimeout);
+			PluginCallback callback,
+			int maxLatency,
+			int maxIdleTime,
+			int connectionTimeout) {
+		super(ioExecutor, wakefulIoExecutor, backoff, callback, maxLatency,
+				maxIdleTime, connectionTimeout);
 	}
 
 	@Override
@@ -91,29 +108,36 @@ class LanTcpPlugin extends TcpPlugin {
 	public void start() {
 		if (used.getAndSet(true)) throw new IllegalStateException();
 		initialisePortProperty();
-		running = true;
+		Settings settings = callback.getSettings();
+		state.setStarted(settings.getBoolean(PREF_PLUGIN_ENABLE,
+				DEFAULT_PREF_PLUGIN_ENABLE));
 		bind();
 	}
 
 	protected void initialisePortProperty() {
 		TransportProperties p = callback.getLocalProperties();
 		if (isNullOrEmpty(p.get(PROP_PORT))) {
-			int port = new Random().nextInt(32768) + 32768;
+			int port = chooseEphemeralPort();
 			p.put(PROP_PORT, String.valueOf(port));
 			callback.mergeLocalProperties(p);
 		}
 	}
 
 	@Override
-	protected List<InetSocketAddress> getLocalSocketAddresses() {
+	protected boolean isEnabledByDefault() {
+		return DEFAULT_PREF_PLUGIN_ENABLE;
+	}
+
+	@Override
+	protected List<InetSocketAddress> getLocalSocketAddresses(boolean ipv4) {
 		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> olds = parseIpv4SocketAddresses(oldIpPorts);
 
 		List<InetSocketAddress> locals = new ArrayList<>();
 		List<InetSocketAddress> fallbacks = new ArrayList<>();
-		for (InetAddress local : getUsableLocalInetAddresses()) {
+		for (InetAddress local : getUsableLocalInetAddresses(ipv4)) {
 			// If we've used this address before, try to use the same port
 			int port = preferredPort;
 			for (InetSocketAddress old : olds) {
@@ -139,17 +163,17 @@ class LanTcpPlugin extends TcpPlugin {
 		}
 	}
 
-	private List<InetSocketAddress> parseSocketAddresses(String ipPorts) {
+	private List<InetSocketAddress> parseIpv4SocketAddresses(String ipPorts) {
 		List<InetSocketAddress> addresses = new ArrayList<>();
 		if (isNullOrEmpty(ipPorts)) return addresses;
 		for (String ipPort : ipPorts.split(SEPARATOR)) {
-			InetSocketAddress a = parseSocketAddress(ipPort);
+			InetSocketAddress a = parseIpv4SocketAddress(ipPort);
 			if (a != null) addresses.add(a);
 		}
 		return addresses;
 	}
 
-	protected List<InetAddress> getUsableLocalInetAddresses() {
+	protected List<InetAddress> getUsableLocalInetAddresses(boolean ipv4) {
 		List<InterfaceAddress> ifAddrs =
 				new ArrayList<>(getLocalInterfaceAddresses());
 		// Prefer longer network prefixes
@@ -158,50 +182,74 @@ class LanTcpPlugin extends TcpPlugin {
 		List<InetAddress> addrs = new ArrayList<>();
 		for (InterfaceAddress ifAddr : ifAddrs) {
 			InetAddress addr = ifAddr.getAddress();
-			if (isAcceptableAddress(addr)) addrs.add(addr);
+			if (isAcceptableAddress(addr, ipv4)) addrs.add(addr);
 		}
 		return addrs;
 	}
 
 	@Override
-	protected void setLocalSocketAddress(InetSocketAddress a) {
+	protected void setLocalSocketAddress(InetSocketAddress a, boolean ipv4) {
+		if (ipv4) setLocalIpv4SocketAddress(a);
+		else setLocalIpv6SocketAddress(a);
+	}
+
+	private void setLocalIpv4SocketAddress(InetSocketAddress a) {
 		String ipPort = getIpPortString(a);
+		updateRecentAddresses(PREF_LAN_IP_PORTS, PROP_IP_PORTS, ipPort);
+	}
+
+	private void setLocalIpv6SocketAddress(InetSocketAddress a) {
+		String hex = toHexString(a.getAddress().getAddress());
+		updateRecentAddresses(PREF_IPV6, PROP_IPV6, hex);
+	}
+
+	private void updateRecentAddresses(String settingKey, String propertyKey,
+			String item) {
 		// Get the list of recently used addresses
-		String setting = callback.getSettings().get(PREF_LAN_IP_PORTS);
+		String setting = callback.getSettings().get(settingKey);
-		List<String> recent = new ArrayList<>();
+		Deque<String> recent = new LinkedList<>();
-		if (!isNullOrEmpty(setting))
+		if (!isNullOrEmpty(setting)) {
 			addAll(recent, setting.split(SEPARATOR));
-		// Is the address already in the list?
+		}
-		if (recent.remove(ipPort)) {
+		if (recent.remove(item)) {
-			// Move the address to the start of the list
+			// Move the item to the start of the list
-			recent.add(0, ipPort);
+			recent.addFirst(item);
 			setting = join(recent, SEPARATOR);
 		} else {
-			// Add the address to the start of the list
+			// Add the item to the start of the list
-			recent.add(0, ipPort);
+			recent.addFirst(item);
-			// Drop the least recently used address if the list is full
+			// Drop items from the end of the list if it's too long to encode
-			if (recent.size() > MAX_ADDRESSES)
-				recent = recent.subList(0, MAX_ADDRESSES);
 			setting = join(recent, SEPARATOR);
+			while (utf8IsTooLong(setting, MAX_PROPERTY_LENGTH)) {
+				recent.removeLast();
+				setting = join(recent, SEPARATOR);
+			}
 			// Update the list of addresses shared with contacts
-			List<String> shared = new ArrayList<>(recent);
-			sort(shared);
-			String property = join(shared, SEPARATOR);
 			TransportProperties properties = new TransportProperties();
-			properties.put(PROP_IP_PORTS, property);
+			properties.put(propertyKey, setting);
 			callback.mergeLocalProperties(properties);
 		}
 		// Save the setting
 		Settings settings = new Settings();
-		settings.put(PREF_LAN_IP_PORTS, setting);
+		settings.put(settingKey, setting);
 		callback.mergeSettings(settings);
 	}
 
+	protected boolean isIpv6LinkLocalAddress(InetAddress a) {
+		return a instanceof Inet6Address && a.isLinkLocalAddress();
+	}
+
 	@Override
 	protected List<InetSocketAddress> getRemoteSocketAddresses(
+			TransportProperties p, boolean ipv4) {
+		if (ipv4) return getRemoteIpv4SocketAddresses(p);
+		else return getRemoteIpv6SocketAddresses(p);
+	}
+
+	private List<InetSocketAddress> getRemoteIpv4SocketAddresses(
 			TransportProperties p) {
 		String ipPorts = p.get(PROP_IP_PORTS);
-		List<InetSocketAddress> remotes = parseSocketAddresses(ipPorts);
+		List<InetSocketAddress> remotes = parseIpv4SocketAddresses(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
@@ -216,20 +264,52 @@ class LanTcpPlugin extends TcpPlugin {
 		return remotes;
 	}
 
-	private boolean isAcceptableAddress(InetAddress a) {
+	private List<InetSocketAddress> getRemoteIpv6SocketAddresses(
-		// Accept link-local and site-local IPv4 addresses
+			TransportProperties p) {
-		boolean ipv4 = a instanceof Inet4Address;
+		List<InetAddress> addrs = parseIpv6Addresses(p.get(PROP_IPV6));
-		boolean loop = a.isLoopbackAddress();
+		int port = parsePortProperty(p.get(PROP_PORT));
-		boolean link = a.isLinkLocalAddress();
+		if (addrs.isEmpty() || port == 0) return emptyList();
-		boolean site = a.isSiteLocalAddress();
+		List<InetSocketAddress> remotes = new ArrayList<>();
-		return ipv4 && !loop && (link || site);
+		for (InetAddress addr : addrs) {
+			remotes.add(new InetSocketAddress(addr, port));
+		}
+		return remotes;
+	}
+
+	private List<InetAddress> parseIpv6Addresses(String property) {
+		if (isNullOrEmpty(property)) return emptyList();
+		try {
+			List<InetAddress> addrs = new ArrayList<>();
+			for (String hex : property.split(SEPARATOR)) {
+				byte[] ip = fromHexString(hex);
+				if (ip.length == 16) addrs.add(InetAddress.getByAddress(ip));
+			}
+			return addrs;
+		} catch (IllegalArgumentException | UnknownHostException e) {
+			return emptyList();
+		}
+	}
+
+	private boolean isAcceptableAddress(InetAddress a, boolean ipv4) {
+		if (ipv4) {
+			// Accept link-local and site-local IPv4 addresses
+			boolean isIpv4 = a instanceof Inet4Address;
+			boolean link = a.isLinkLocalAddress();
+			boolean site = a.isSiteLocalAddress();
+			return isIpv4 && (link || site);
+		} else {
+			// Accept link-local IPv6 addresses
+			return isIpv6LinkLocalAddress(a);
+		}
 	}
 
 	@Override
 	protected boolean isConnectable(InterfaceAddress local,
 			InetSocketAddress remote) {
 		if (remote.getPort() == 0) return false;
-		if (!isAcceptableAddress(remote.getAddress())) return false;
+		InetAddress remoteAddress = remote.getAddress();
+		boolean ipv4 = local.getAddress() instanceof Inet4Address;
+		if (!isAcceptableAddress(remoteAddress, ipv4)) return false;
 		// Try to determine whether the address is on the same LAN as us
 		byte[] localIp = local.getAddress().getAddress();
 		byte[] remoteIp = remote.getAddress().getAddress();
@@ -271,7 +351,7 @@ class LanTcpPlugin extends TcpPlugin {
 			} catch (IOException e) {
 				if (LOG.isLoggable(INFO))
 					LOG.info("Failed to bind " + scrubSocketAddress(addr));
-				tryToClose(ss);
+				tryToClose(ss, LOG, WARNING);
 			}
 		}
 		if (ss == null || !ss.isBound()) {
@@ -287,11 +367,18 @@ class LanTcpPlugin extends TcpPlugin {
 		return new LanKeyAgreementListener(descriptor, ss);
 	}
 
+	private List<InetSocketAddress> getLocalSocketAddresses() {
+		List<InetSocketAddress> addrs = new ArrayList<>();
+		addrs.addAll(getLocalSocketAddresses(true));
+		addrs.addAll(getLocalSocketAddresses(false));
+		return addrs;
+	}
+
 	@Override
 	public DuplexTransportConnection createKeyAgreementConnection(
 			byte[] commitment, BdfList descriptor) {
-		if (!isRunning()) return null;
+		ServerSocket ss = state.getServerSocket(true);
-		ServerSocket ss = socket;
+		if (ss == null) return null;
 		InterfaceAddress local = getLocalInterfaceAddress(ss.getInetAddress());
 		if (local == null) {
 			LOG.warning("No interface for key agreement server socket");
@@ -363,7 +450,7 @@ class LanTcpPlugin extends TcpPlugin {
 
 		@Override
 		public void close() {
-			IoUtils.tryToClose(ss, LOG, WARNING);
+			tryToClose(ss, LOG, WARNING);
 		}
 	}
 }

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

@@ -1,5 +1,7 @@
 package org.briarproject.bramble.plugin.tcp;
 
+import org.briarproject.bramble.api.event.EventBus;
+import org.briarproject.bramble.api.lifecycle.IoExecutor;
 import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
 import org.briarproject.bramble.api.plugin.Backoff;
 import org.briarproject.bramble.api.plugin.BackoffFactory;
@@ -7,10 +9,12 @@ 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.WakefulIoExecutor;
 
 import java.util.concurrent.Executor;
 
 import javax.annotation.concurrent.Immutable;
+import javax.inject.Inject;
 
 import static org.briarproject.bramble.api.plugin.LanTcpConstants.ID;
 
@@ -25,12 +29,18 @@ public class LanTcpPluginFactory implements DuplexPluginFactory {
 	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 Executor ioExecutor, wakefulIoExecutor;
+	private final EventBus eventBus;
 	private final BackoffFactory backoffFactory;
 
-	public LanTcpPluginFactory(Executor ioExecutor,
+	@Inject
+	public LanTcpPluginFactory(@IoExecutor Executor ioExecutor,
+			@WakefulIoExecutor Executor wakefulIoExecutor,
+			EventBus eventBus,
 			BackoffFactory backoffFactory) {
 		this.ioExecutor = ioExecutor;
+		this.wakefulIoExecutor = wakefulIoExecutor;
+		this.eventBus = eventBus;
 		this.backoffFactory = backoffFactory;
 	}
 
@@ -48,7 +58,10 @@ public class LanTcpPluginFactory implements DuplexPluginFactory {
 	public DuplexPlugin createPlugin(PluginCallback callback) {
 		Backoff backoff = backoffFactory.createBackoff(MIN_POLLING_INTERVAL,
 				MAX_POLLING_INTERVAL, BACKOFF_BASE);
-		return new LanTcpPlugin(ioExecutor, backoff, callback, MAX_LATENCY,
+		LanTcpPlugin plugin = new LanTcpPlugin(ioExecutor, wakefulIoExecutor,
-				MAX_IDLE_TIME, CONNECTION_TIMEOUT);
+				backoff, callback, MAX_LATENCY, MAX_IDLE_TIME,
+				CONNECTION_TIMEOUT);
+		eventBus.addListener(plugin);
+		return plugin;
 	}
 }

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

@@ -54,11 +54,13 @@ class PortMapperImpl implements PortMapper {
 				shutdownManager.addShutdownHook(() -> deleteMapping(port));
 			}
 			String externalString = gateway.getExternalIPAddress();
-			if (LOG.isLoggable(INFO))
+			if (externalString == null) {
-				LOG.info(
+				LOG.info("External address not available");
-						"External address " + scrubInetAddress(externalString));
+			} else {
-			if (externalString != null)
 				external = InetAddress.getByName(externalString);
+				if (LOG.isLoggable(INFO))
+					LOG.info("External address " + scrubInetAddress(external));
+			}
 		} catch (IOException | SAXException e) {
 			logException(LOG, WARNING, e);
 		}

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

@@ -3,8 +3,12 @@ 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;
@@ -14,7 +18,8 @@ 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.util.IoUtils;
+import org.briarproject.bramble.api.settings.Settings;
+import org.briarproject.bramble.api.settings.event.SettingsUpdatedEvent;
 
 import java.io.IOException;
 import java.net.InetAddress;
@@ -35,53 +40,60 @@ 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.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.api.plugin.Plugin.State.STARTING_STOPPING;
+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 {
+abstract class TcpPlugin implements DuplexPlugin, EventListener {
 
 	private static final Logger LOG = getLogger(TcpPlugin.class.getName());
 
 	private static final Pattern DOTTED_QUAD =
 			Pattern.compile("^\\d{1,3}\\.\\d{1,3}\\.\\d{1,3}\\.\\d{1,3}$");
 
-	protected final Executor ioExecutor, bindExecutor;
+	protected final Executor ioExecutor, wakefulIoExecutor, bindExecutor;
 	protected final Backoff backoff;
 	protected final PluginCallback callback;
 	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,
 	 * in order of preference. At most one of the addresses will be bound.
 	 */
-	protected abstract List<InetSocketAddress> getLocalSocketAddresses();
+	protected abstract List<InetSocketAddress> getLocalSocketAddresses(
+			boolean ipv4);
 
 	/**
 	 * Adds the address on which the plugin is listening to the transport
 	 * properties.
 	 */
-	protected abstract void setLocalSocketAddress(InetSocketAddress a);
+	protected abstract void setLocalSocketAddress(InetSocketAddress a,
+			boolean ipv4);
 
 	/**
 	 * Returns zero or more socket addresses for connecting to a contact with
 	 * the given transport properties.
 	 */
 	protected abstract List<InetSocketAddress> getRemoteSocketAddresses(
-			TransportProperties p);
+			TransportProperties p, boolean ipv4);
 
 	/**
 	 * Returns true if connections to the given address can be attempted.
@@ -90,9 +102,20 @@ abstract class TcpPlugin implements DuplexPlugin {
 	protected abstract boolean isConnectable(InterfaceAddress local,
 			InetSocketAddress remote);
 
-	TcpPlugin(Executor ioExecutor, Backoff backoff, PluginCallback callback,
+	/**
-			int maxLatency, int maxIdleTime, int connectionTimeout) {
+	 * Returns true if the plugin is enabled by default.
+	 */
+	protected abstract boolean isEnabledByDefault();
+
+	TcpPlugin(Executor ioExecutor,
+			Executor wakefulIoExecutor,
+			Backoff backoff,
+			PluginCallback callback,
+			int maxLatency,
+			int maxIdleTime,
+			int connectionTimeout) {
 		this.ioExecutor = ioExecutor;
+		this.wakefulIoExecutor = wakefulIoExecutor;
 		this.backoff = backoff;
 		this.callback = callback;
 		this.maxLatency = maxLatency;
@@ -118,49 +141,56 @@ abstract class TcpPlugin implements DuplexPlugin {
 	@Override
 	public void start() {
 		if (used.getAndSet(true)) throw new IllegalStateException();
-		running = true;
+		Settings settings = callback.getSettings();
+		state.setStarted(
+				settings.getBoolean(PREF_PLUGIN_ENABLE, isEnabledByDefault()));
 		bind();
 	}
 
 	protected void bind() {
 		bindExecutor.execute(() -> {
-			if (!running) return;
+			State s = getState();
-			if (socket != null && !socket.isClosed()) return;
+			if (s != ACTIVE && s != INACTIVE) return;
-			ServerSocket ss = null;
+			bind(true);
-			for (InetSocketAddress addr : getLocalSocketAddresses()) {
+			bind(false);
-				try {
-					ss = new ServerSocket();
-					ss.bind(addr);
-					break;
-				} catch (IOException e) {
-					if (LOG.isLoggable(INFO))
-						LOG.info("Failed to bind " + scrubSocketAddress(addr));
-					tryToClose(ss);
-				}
-			}
-			if (ss == null || !ss.isBound()) {
-				LOG.info("Could not bind server socket");
-				return;
-			}
-			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));
-			callback.transportEnabled();
-			acceptContactConnections();
 		});
 	}
 
-	protected void tryToClose(@Nullable ServerSocket ss) {
+	private void bind(boolean ipv4) {
-		IoUtils.tryToClose(ss, LOG, WARNING);
+		ServerSocket old = state.getServerSocket(ipv4);
-		callback.transportDisabled();
+		ServerSocket ss = null;
+		for (InetSocketAddress addr : getLocalSocketAddresses(ipv4)) {
+			if (old != null && addr.equals(old.getLocalSocketAddress())) {
+				LOG.info("Server socket already bound");
+				return;
+			}
+			try {
+				ss = new ServerSocket();
+				ss.bind(addr);
+				break;
+			} catch (IOException e) {
+				if (LOG.isLoggable(INFO))
+					LOG.info("Failed to bind " + scrubSocketAddress(addr));
+				tryToClose(ss, LOG, WARNING);
+			}
+		}
+		if (ss == null || !ss.isBound()) {
+			LOG.info("Could not bind server socket");
+			return;
+		}
+		if (!state.setServerSocket(ss, ipv4)) {
+			LOG.info("Closing redundant server socket");
+			tryToClose(ss, LOG, WARNING);
+			return;
+		}
+		backoff.reset();
+		InetSocketAddress local =
+				(InetSocketAddress) ss.getLocalSocketAddress();
+		setLocalSocketAddress(local, ipv4);
+		if (LOG.isLoggable(INFO))
+			LOG.info("Listening on " + scrubSocketAddress(local));
+		ServerSocket finalSocket = ss;
+		ioExecutor.execute(() -> acceptContactConnections(finalSocket, ipv4));
 	}
 
 	String getIpPortString(InetSocketAddress a) {
@@ -170,20 +200,22 @@ abstract class TcpPlugin implements DuplexPlugin {
 		return addr + ":" + a.getPort();
 	}
 
-	private void acceptContactConnections() {
+	private void acceptContactConnections(ServerSocket ss, boolean ipv4) {
-		while (isRunning()) {
+		while (true) {
 			Socket s;
 			try {
-				s = socket.accept();
+				s = ss.accept();
 				s.setSoTimeout(socketTimeout);
 			} catch (IOException e) {
-				// This is expected when the socket is closed
+				// This is expected when the server socket is closed
-				if (LOG.isLoggable(INFO)) LOG.info(e.toString());
+				LOG.info("Server socket closed");
+				state.clearServerSocket(ss, ipv4);
 				return;
 			}
-			if (LOG.isLoggable(INFO))
+			if (LOG.isLoggable(INFO)) {
 				LOG.info("Connection from " +
 						scrubSocketAddress(s.getRemoteSocketAddress()));
+			}
 			backoff.reset();
 			callback.handleConnection(new TcpTransportConnection(this, s));
 		}
@@ -191,13 +223,17 @@ abstract class TcpPlugin implements DuplexPlugin {
 
 	@Override
 	public void stop() {
-		running = false;
+		for (ServerSocket ss : state.setStopped()) tryToClose(ss, LOG, WARNING);
-		tryToClose(socket);
 	}
 
 	@Override
-	public boolean isRunning() {
+	public State getState() {
-		return running && socket != null && !socket.isClosed();
+		return state.getState();
+	}
+
+	@Override
+	public int getReasonsDisabled() {
+		return state.getReasonsDisabled();
 	}
 
 	@Override
@@ -213,7 +249,7 @@ abstract class TcpPlugin implements DuplexPlugin {
 	@Override
 	public void poll(Collection<Pair<TransportProperties, ConnectionHandler>>
 			properties) {
-		if (!isRunning()) return;
+		if (getState() != ACTIVE) return;
 		backoff.increment();
 		for (Pair<TransportProperties, ConnectionHandler> p : properties) {
 			connect(p.getFirst(), p.getSecond());
@@ -221,7 +257,7 @@ abstract class TcpPlugin implements DuplexPlugin {
 	}
 
 	private void connect(TransportProperties p, ConnectionHandler h) {
-		ioExecutor.execute(() -> {
+		wakefulIoExecutor.execute(() -> {
 			DuplexTransportConnection d = createConnection(p);
 			if (d != null) {
 				backoff.reset();
@@ -232,14 +268,22 @@ abstract class TcpPlugin implements DuplexPlugin {
 
 	@Override
 	public DuplexTransportConnection createConnection(TransportProperties p) {
-		if (!isRunning()) return null;
+		DuplexTransportConnection c = createConnection(p, true);
-		ServerSocket ss = socket;
+		if (c != null) return c;
+		return createConnection(p, false);
+	}
+
+	@Nullable
+	private DuplexTransportConnection createConnection(TransportProperties p,
+			boolean ipv4) {
+		ServerSocket ss = state.getServerSocket(ipv4);
+		if (ss == null) return null;
 		InterfaceAddress local = getLocalInterfaceAddress(ss.getInetAddress());
 		if (local == null) {
 			LOG.warning("No interface for server socket");
 			return null;
 		}
-		for (InetSocketAddress remote : getRemoteSocketAddresses(p)) {
+		for (InetSocketAddress remote : getRemoteSocketAddresses(p, ipv4)) {
 			// Don't try to connect to our own address
 			if (!canConnectToOwnAddress() &&
 					remote.getAddress().equals(ss.getInetAddress())) {
@@ -264,9 +308,10 @@ abstract class TcpPlugin implements DuplexPlugin {
 					LOG.info("Connected to " + scrubSocketAddress(remote));
 				return new TcpTransportConnection(this, s);
 			} catch (IOException e) {
-				if (LOG.isLoggable(INFO))
+				if (LOG.isLoggable(INFO)) {
 					LOG.info("Could not connect to " +
 							scrubSocketAddress(remote));
+				}
 			}
 		}
 		return null;
@@ -289,8 +334,12 @@ abstract class TcpPlugin implements DuplexPlugin {
 		return new Socket();
 	}
 
+	int chooseEphemeralPort() {
+		return 32768 + (int) (Math.random() * 32768);
+	}
+
 	@Nullable
-	InetSocketAddress parseSocketAddress(String ipPort) {
+	InetSocketAddress parseIpv4SocketAddress(String ipPort) {
 		if (isNullOrEmpty(ipPort)) return null;
 		String[] split = ipPort.split(":");
 		if (split.length != 2) return null;
@@ -301,14 +350,7 @@ abstract class TcpPlugin implements DuplexPlugin {
 			InetAddress a = InetAddress.getByName(addr);
 			int p = Integer.parseInt(port);
 			return new InetSocketAddress(a, p);
-		} catch (UnknownHostException e) {
+		} catch (UnknownHostException | NumberFormatException e) {
-			if (LOG.isLoggable(WARNING))
-				// not scrubbing to enable us to find the problem
-				LOG.warning("Invalid address: " + addr);
-			return null;
-		} catch (NumberFormatException e) {
-			if (LOG.isLoggable(WARNING))
-				LOG.warning("Invalid port: " + port);
 			return null;
 		}
 	}
@@ -366,4 +408,114 @@ abstract class TcpPlugin implements DuplexPlugin {
 			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, isEnabledByDefault());
+		List<ServerSocket> toClose = state.setEnabledByUser(enabledByUser);
+		State s = getState();
+		if (!toClose.isEmpty()) {
+			LOG.info("Disabled by user, closing server sockets");
+			for (ServerSocket ss : toClose) tryToClose(ss, LOG, WARNING);
+		} else if (s == INACTIVE) {
+			LOG.info("Enabled by user, opening server sockets");
+			bind();
+		}
+	}
+
+	@ThreadSafe
+	@NotNullByDefault
+	protected class PluginState {
+
+		@GuardedBy("this")
+		private boolean started = false, stopped = false, enabledByUser = false;
+
+		@GuardedBy("this")
+		@Nullable
+		private ServerSocket serverSocketV4 = null, serverSocketV6 = null;
+
+		synchronized void setStarted(boolean enabledByUser) {
+			started = true;
+			this.enabledByUser = enabledByUser;
+			callback.pluginStateChanged(getState());
+		}
+
+		synchronized List<ServerSocket> setStopped() {
+			stopped = true;
+			List<ServerSocket> toClose = clearServerSockets();
+			callback.pluginStateChanged(getState());
+			return toClose;
+		}
+
+		@GuardedBy("this")
+		private List<ServerSocket> clearServerSockets() {
+			List<ServerSocket> toClose = new ArrayList<>(2);
+			if (serverSocketV4 != null) {
+				toClose.add(serverSocketV4);
+				serverSocketV4 = null;
+			}
+			if (serverSocketV6 != null) {
+				toClose.add(serverSocketV6);
+				serverSocketV6 = null;
+			}
+			return toClose;
+		}
+
+		synchronized List<ServerSocket> setEnabledByUser(
+				boolean enabledByUser) {
+			this.enabledByUser = enabledByUser;
+			List<ServerSocket> toClose = enabledByUser
+					? emptyList() : clearServerSockets();
+			callback.pluginStateChanged(getState());
+			return toClose;
+		}
+
+		@Nullable
+		synchronized ServerSocket getServerSocket(boolean ipv4) {
+			return ipv4 ? serverSocketV4 : serverSocketV6;
+		}
+
+		synchronized boolean setServerSocket(ServerSocket ss, boolean ipv4) {
+			if (stopped) return false;
+			if (ipv4) {
+				if (serverSocketV4 != null) return false;
+				serverSocketV4 = ss;
+			} else {
+				if (serverSocketV6 != null) return false;
+				serverSocketV6 = ss;
+			}
+			callback.pluginStateChanged(getState());
+			return true;
+		}
+
+		synchronized void clearServerSocket(ServerSocket ss, boolean ipv4) {
+			if (ipv4) {
+				if (serverSocketV4 == ss) serverSocketV4 = null;
+			} else {
+				if (serverSocketV6 == ss) serverSocketV6 = null;
+			}
+			callback.pluginStateChanged(getState());
+		}
+
+		synchronized State getState() {
+			if (!started || stopped) return STARTING_STOPPING;
+			if (!enabledByUser) return DISABLED;
+			if (serverSocketV4 != null || serverSocketV6 != null) return ACTIVE;
+			return INACTIVE;
+		}
+
+		synchronized int getReasonsDisabled() {
+			return getState() == DISABLED ? REASON_USER : 0;
+		}
+	}
 }

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

@@ -17,6 +17,7 @@ import java.util.concurrent.Executor;
 
 import static java.util.Collections.emptyList;
 import static java.util.Collections.singletonList;
+import static org.briarproject.bramble.api.plugin.WanTcpConstants.DEFAULT_PREF_PLUGIN_ENABLE;
 import static org.briarproject.bramble.api.plugin.WanTcpConstants.ID;
 
 @MethodsNotNullByDefault
@@ -29,11 +30,16 @@ class WanTcpPlugin extends TcpPlugin {
 
 	private volatile MappingResult mappingResult;
 
-	WanTcpPlugin(Executor ioExecutor, Backoff backoff, PortMapper portMapper,
+	WanTcpPlugin(Executor ioExecutor,
-			PluginCallback callback, int maxLatency, int maxIdleTime,
+			Executor wakefulIoExecutor,
+			Backoff backoff,
+			PortMapper portMapper,
+			PluginCallback callback,
+			int maxLatency,
+			int maxIdleTime,
 			int connectionTimeout) {
-		super(ioExecutor, backoff, callback, maxLatency, maxIdleTime,
+		super(ioExecutor, wakefulIoExecutor, backoff, callback, maxLatency,
-				connectionTimeout);
+				maxIdleTime, connectionTimeout);
 		this.portMapper = portMapper;
 	}
 
@@ -43,10 +49,16 @@ class WanTcpPlugin extends TcpPlugin {
 	}
 
 	@Override
-	protected List<InetSocketAddress> getLocalSocketAddresses() {
+	protected boolean isEnabledByDefault() {
+		return DEFAULT_PREF_PLUGIN_ENABLE;
+	}
+
+	@Override
+	protected List<InetSocketAddress> getLocalSocketAddresses(boolean ipv4) {
+		if (!ipv4) return emptyList();
 		// Use the same address and port as last time if available
 		TransportProperties p = callback.getLocalProperties();
-		InetSocketAddress old = parseSocketAddress(p.get(PROP_IP_PORT));
+		InetSocketAddress old = parseIpv4SocketAddress(p.get(PROP_IP_PORT));
 		List<InetSocketAddress> addrs = new LinkedList<>();
 		for (InetAddress a : getLocalInetAddresses()) {
 			if (isAcceptableAddress(a)) {
@@ -76,14 +88,11 @@ class WanTcpPlugin extends TcpPlugin {
 		return ipv4 && !loop && !link && !site;
 	}
 
-	private int chooseEphemeralPort() {
-		return 32768 + (int) (Math.random() * 32768);
-	}
-
 	@Override
 	protected List<InetSocketAddress> getRemoteSocketAddresses(
-			TransportProperties p) {
+			TransportProperties p, boolean ipv4) {
-		InetSocketAddress parsed = parseSocketAddress(p.get(PROP_IP_PORT));
+		if (!ipv4) return emptyList();
+		InetSocketAddress parsed = parseIpv4SocketAddress(p.get(PROP_IP_PORT));
 		if (parsed == null) return emptyList();
 		return singletonList(parsed);
 	}
@@ -96,7 +105,8 @@ class WanTcpPlugin extends TcpPlugin {
 	}
 
 	@Override
-	protected void setLocalSocketAddress(InetSocketAddress a) {
+	protected void setLocalSocketAddress(InetSocketAddress a, boolean ipv4) {
+		if (!ipv4) throw new AssertionError();
 		if (mappingResult != null && mappingResult.isUsable()) {
 			// Advertise the external address to contacts
 			if (a.equals(mappingResult.getInternal())) {

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

@@ -1,5 +1,7 @@
 package org.briarproject.bramble.plugin.tcp;
 
+import org.briarproject.bramble.api.event.EventBus;
+import org.briarproject.bramble.api.lifecycle.IoExecutor;
 import org.briarproject.bramble.api.lifecycle.ShutdownManager;
 import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
 import org.briarproject.bramble.api.plugin.Backoff;
@@ -8,10 +10,12 @@ 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.WakefulIoExecutor;
 
 import java.util.concurrent.Executor;
 
 import javax.annotation.concurrent.Immutable;
+import javax.inject.Inject;
 
 import static org.briarproject.bramble.api.plugin.WanTcpConstants.ID;
 
@@ -26,13 +30,20 @@ public class WanTcpPluginFactory implements DuplexPluginFactory {
 	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 Executor ioExecutor, wakefulIoExecutor;
+	private final EventBus eventBus;
 	private final BackoffFactory backoffFactory;
 	private final ShutdownManager shutdownManager;
 
-	public WanTcpPluginFactory(Executor ioExecutor,
+	@Inject
-			BackoffFactory backoffFactory, ShutdownManager shutdownManager) {
+	public WanTcpPluginFactory(@IoExecutor Executor ioExecutor,
+			@WakefulIoExecutor Executor wakefulIoExecutor,
+			EventBus eventBus,
+			BackoffFactory backoffFactory,
+			ShutdownManager shutdownManager) {
 		this.ioExecutor = ioExecutor;
+		this.wakefulIoExecutor = wakefulIoExecutor;
+		this.eventBus = eventBus;
 		this.backoffFactory = backoffFactory;
 		this.shutdownManager = shutdownManager;
 	}
@@ -51,8 +62,11 @@ public class WanTcpPluginFactory implements DuplexPluginFactory {
 	public DuplexPlugin createPlugin(PluginCallback callback) {
 		Backoff backoff = backoffFactory.createBackoff(MIN_POLLING_INTERVAL,
 				MAX_POLLING_INTERVAL, BACKOFF_BASE);
-		return new WanTcpPlugin(ioExecutor, backoff,
+		PortMapper portMapper = new PortMapperImpl(shutdownManager);
-				new PortMapperImpl(shutdownManager), callback, MAX_LATENCY,
+		WanTcpPlugin plugin = new WanTcpPlugin(ioExecutor, wakefulIoExecutor,
-				MAX_IDLE_TIME, CONNECTION_TIMEOUT);
+				backoff, portMapper, callback, MAX_LATENCY, MAX_IDLE_TIME,
+				CONNECTION_TIMEOUT);
+		eventBus.addListener(plugin);
+		return plugin;
 	}
 }

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

@@ -17,7 +17,7 @@ public interface CircumventionProvider {
 	String[] BLOCKED = {"CN", "IR", "EG", "BY", "TR", "SY", "VE"};
 
 	/**
-	 * Countries where obfs4 bridge connection are likely to work.
+	 * Countries where obfs4 or meek bridge connections are likely to work.
 	 * Should be a subset of {@link #BLOCKED}.
 	 */
 	String[] BRIDGES = { "CN", "IR", "EG", "BY", "TR", "SY", "VE" };

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

@@ -15,6 +15,7 @@ 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;
@@ -54,6 +55,9 @@ 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;
@@ -65,7 +69,19 @@ 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.Plugin.State.STARTING_STOPPING;
 import static org.briarproject.bramble.api.plugin.TorConstants.CONTROL_PORT;
+import static org.briarproject.bramble.api.plugin.TorConstants.DEFAULT_PREF_PLUGIN_ENABLE;
+import static org.briarproject.bramble.api.plugin.TorConstants.DEFAULT_PREF_TOR_MOBILE;
+import static org.briarproject.bramble.api.plugin.TorConstants.DEFAULT_PREF_TOR_NETWORK;
+import static org.briarproject.bramble.api.plugin.TorConstants.DEFAULT_PREF_TOR_ONLY_WHEN_CHARGING;
+import static org.briarproject.bramble.api.plugin.TorConstants.HS_PRIVATE_KEY_V2;
+import static org.briarproject.bramble.api.plugin.TorConstants.HS_PRIVATE_KEY_V3;
+import static org.briarproject.bramble.api.plugin.TorConstants.HS_V3_CREATED;
 import static org.briarproject.bramble.api.plugin.TorConstants.ID;
 import static org.briarproject.bramble.api.plugin.TorConstants.PREF_TOR_MOBILE;
 import static org.briarproject.bramble.api.plugin.TorConstants.PREF_TOR_NETWORK;
@@ -76,6 +92,10 @@ 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.api.plugin.TorConstants.V3_MIGRATION_PERIOD_MS;
 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;
@@ -98,7 +118,8 @@ abstract class TorPlugin implements DuplexPlugin, EventHandler, EventListener {
 	private static final Pattern ONION_V2 = Pattern.compile("[a-z2-7]{16}");
 	private static final Pattern ONION_V3 = Pattern.compile("[a-z2-7]{56}");
 
-	private final Executor ioExecutor, connectionStatusExecutor;
+	private final Executor ioExecutor, wakefulIoExecutor;
+	private final Executor connectionStatusExecutor;
 	private final NetworkManager networkManager;
 	private final LocationUtils locationUtils;
 	private final SocketFactory torSocketFactory;
@@ -113,29 +134,36 @@ 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);
 
-	private volatile ServerSocket socket = null;
+	protected final PluginState state = new PluginState();
+
 	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();
 
-	TorPlugin(Executor ioExecutor, NetworkManager networkManager,
+	TorPlugin(Executor ioExecutor,
-			LocationUtils locationUtils, SocketFactory torSocketFactory,
+			Executor wakefulIoExecutor,
-			Clock clock, ResourceProvider resourceProvider,
+			NetworkManager networkManager,
+			LocationUtils locationUtils,
+			SocketFactory torSocketFactory,
+			Clock clock,
+			ResourceProvider resourceProvider,
 			CircumventionProvider circumventionProvider,
-			BatteryManager batteryManager, Backoff backoff,
+			BatteryManager batteryManager,
+			Backoff backoff,
 			TorRendezvousCrypto torRendezvousCrypto,
-			PluginCallback callback, String architecture, int maxLatency,
+			PluginCallback callback,
-			int maxIdleTime, File torDirectory) {
+			String architecture,
+			int maxLatency,
+			int maxIdleTime,
+			File torDirectory) {
 		this.ioExecutor = ioExecutor;
+		this.wakefulIoExecutor = wakefulIoExecutor;
 		this.networkManager = networkManager;
 		this.locationUtils = locationUtils;
 		this.torSocketFactory = torSocketFactory;
@@ -159,7 +187,6 @@ 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);
@@ -190,7 +217,7 @@ abstract class TorPlugin implements DuplexPlugin, EventHandler, EventListener {
 			}
 		}
 		// Load the settings
-		settings = callback.getSettings();
+		settings = migrateSettings(callback.getSettings());
 		// Install or update the assets if necessary
 		if (!assetsAreUpToDate()) installAssets();
 		if (cookieFile.exists() && !cookieFile.delete())
@@ -258,7 +285,6 @@ 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));
@@ -266,11 +292,12 @@ 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");
-				connectionStatus.setBootstrapped();
+				state.setBootstrapped();
 			}
 		} catch (IOException e) {
 			throw new PluginException(e);
 		}
+		state.setStarted();
 		// Check whether we're online
 		updateConnectionStatus(networkManager.getNetworkStatus(),
 				batteryManager.isCharging());
@@ -278,6 +305,18 @@ abstract class TorPlugin implements DuplexPlugin, EventHandler, EventListener {
 		bind();
 	}
 
+	// TODO: Remove after a reasonable migration period (added 2020-06-25)
+	private Settings migrateSettings(Settings settings) {
+		int network = settings.getInt(PREF_TOR_NETWORK,
+				DEFAULT_PREF_TOR_NETWORK);
+		if (network == PREF_TOR_NETWORK_NEVER) {
+			settings.putInt(PREF_TOR_NETWORK, DEFAULT_PREF_TOR_NETWORK);
+			settings.putBoolean(PREF_PLUGIN_ENABLE, false);
+			callback.mergeSettings(settings);
+		}
+		return settings;
+	}
+
 	private boolean assetsAreUpToDate() {
 		return doneFile.lastModified() > getLastUpdateTime();
 	}
@@ -393,11 +432,11 @@ abstract class TorPlugin implements DuplexPlugin, EventHandler, EventListener {
 				tryToClose(ss, LOG, WARNING);
 				return;
 			}
-			if (!running) {
+			if (!state.setServerSocket(ss)) {
+				LOG.info("Closing redundant server socket");
 				tryToClose(ss, LOG, WARNING);
 				return;
 			}
-			socket = ss;
 			// Store the port number
 			String localPort = String.valueOf(ss.getLocalPort());
 			Settings s = new Settings();
@@ -412,16 +451,67 @@ abstract class TorPlugin implements DuplexPlugin, EventHandler, EventListener {
 	}
 
 	private void publishHiddenService(String port) {
-		if (!running) return;
+		if (!state.isTorRunning()) return;
-		LOG.info("Creating hidden service");
+		// TODO: Remove support for v2 hidden services after a reasonable
-		String privKey = settings.get(HS_PRIVKEY);
+		// migration period (migration started 2020-06-30)
+		String privKey2 = settings.get(HS_PRIVATE_KEY_V2);
+		String privKey3 = settings.get(HS_PRIVATE_KEY_V3);
+		String v3Created = settings.get(HS_V3_CREATED);
+		// Publish a v2 hidden service if we've already created one, and
+		// either we've never published a v3 hidden service or we're still
+		// in the migration period since first publishing it
+		if (!isNullOrEmpty(privKey2)) {
+			long now = clock.currentTimeMillis();
+			long then = v3Created == null ? now : Long.parseLong(v3Created);
+			if (now - then >= V3_MIGRATION_PERIOD_MS) retireV2HiddenService();
+			else publishV2HiddenService(port, privKey2);
+		}
+		publishV3HiddenService(port, privKey3);
+	}
+
+	private void publishV2HiddenService(String port, String privKey) {
+		LOG.info("Creating v2 hidden service");
+		Map<Integer, String> portLines = singletonMap(80, "127.0.0.1:" + port);
+		Map<String, String> response;
+		try {
+			response = controlConnection.addOnion(privKey, portLines);
+		} catch (IOException e) {
+			logException(LOG, WARNING, e);
+			return;
+		}
+		if (!response.containsKey(HS_ADDRESS)) {
+			LOG.warning("Tor did not return a hidden service address");
+			return;
+		}
+		String onion2 = response.get(HS_ADDRESS);
+		if (LOG.isLoggable(INFO)) {
+			LOG.info("V2 hidden service " + scrubOnion(onion2));
+		}
+		// The hostname has already been published and the private key stored
+	}
+
+	private void retireV2HiddenService() {
+		LOG.info("Retiring v2 hidden service");
+		TransportProperties p = new TransportProperties();
+		p.put(PROP_ONION_V2, "");
+		callback.mergeLocalProperties(p);
+		Settings s = new Settings();
+		s.put(HS_PRIVATE_KEY_V2, "");
+		callback.mergeSettings(s);
+	}
+
+	private void publishV3HiddenService(String port, @Nullable String privKey) {
+		LOG.info("Creating v3 hidden service");
 		Map<Integer, String> portLines = singletonMap(80, "127.0.0.1:" + port);
 		Map<String, String> response;
 		try {
 			// Use the control connection to set up the hidden service
-			if (privKey == null)
+			if (privKey == null) {
-				response = controlConnection.addOnion(portLines);
+				response = controlConnection.addOnion("NEW:ED25519-V3",
-			else response = controlConnection.addOnion(privKey, portLines);
+						portLines, null);
+			} else {
+				response = controlConnection.addOnion(privKey, portLines);
+			}
 		} catch (IOException e) {
 			logException(LOG, WARNING, e);
 			return;
@@ -434,30 +524,33 @@ abstract class TorPlugin implements DuplexPlugin, EventHandler, EventListener {
 			LOG.warning("Tor did not return a private key");
 			return;
 		}
-		// Publish the hidden service's onion hostname in transport properties
+		String onion3 = response.get(HS_ADDRESS);
-		String onion2 = response.get(HS_ADDRESS);
+		if (LOG.isLoggable(INFO)) {
-		if (LOG.isLoggable(INFO))
+			LOG.info("V3 hidden service " + scrubOnion(onion3));
-			LOG.info("Hidden service " + scrubOnion(onion2));
+		}
-		TransportProperties p = new TransportProperties();
-		p.put(PROP_ONION_V2, onion2);
-		callback.mergeLocalProperties(p);
 		if (privKey == null) {
+			// Publish the hidden service's onion hostname in transport props
+			TransportProperties p = new TransportProperties();
+			p.put(PROP_ONION_V3, onion3);
+			callback.mergeLocalProperties(p);
 			// Save the hidden service's private key for next time
 			Settings s = new Settings();
-			s.put(HS_PRIVKEY, response.get(HS_PRIVKEY));
+			s.put(HS_PRIVATE_KEY_V3, response.get(HS_PRIVKEY));
+			s.put(HS_V3_CREATED, String.valueOf(clock.currentTimeMillis()));
 			callback.mergeSettings(s);
 		}
 	}
 
 	private void acceptContactConnections(ServerSocket ss) {
-		while (running) {
+		while (true) {
 			Socket s;
 			try {
 				s = ss.accept();
 				s.setSoTimeout(socketTimeout);
 			} catch (IOException e) {
-				// This is expected when the socket is closed
+				// This is expected when the server socket is closed
-				if (LOG.isLoggable(INFO)) LOG.info(e.toString());
+				LOG.info("Server socket closed");
+				state.clearServerSocket(ss);
 				return;
 			}
 			LOG.info("Connection received");
@@ -467,10 +560,8 @@ abstract class TorPlugin implements DuplexPlugin, EventHandler, EventListener {
 	}
 
 	protected void enableNetwork(boolean enable) throws IOException {
-		if (!running) return;
+		state.enableNetwork(enable);
-		connectionStatus.enableNetwork(enable);
 		controlConnection.setConf("DisableNetwork", enable ? "0" : "1");
-		if (!enable) callback.transportDisabled();
 	}
 
 	private void enableBridges(boolean enable, boolean needsMeek)
@@ -494,9 +585,8 @@ abstract class TorPlugin implements DuplexPlugin, EventHandler, EventListener {
 
 	@Override
 	public void stop() {
-		running = false;
+		ServerSocket ss = state.setStopped();
-		tryToClose(socket, LOG, WARNING);
+		tryToClose(ss, LOG, WARNING);
-		callback.transportDisabled();
 		if (controlSocket != null && controlConnection != null) {
 			try {
 				LOG.info("Stopping Tor");
@@ -510,8 +600,13 @@ abstract class TorPlugin implements DuplexPlugin, EventHandler, EventListener {
 	}
 
 	@Override
-	public boolean isRunning() {
+	public State getState() {
-		return running && connectionStatus.isConnected();
+		return state.getState();
+	}
+
+	@Override
+	public int getReasonsDisabled() {
+		return state.getReasonsDisabled();
 	}
 
 	@Override
@@ -527,7 +622,7 @@ abstract class TorPlugin implements DuplexPlugin, EventHandler, EventListener {
 	@Override
 	public void poll(Collection<Pair<TransportProperties, ConnectionHandler>>
 			properties) {
-		if (!isRunning()) return;
+		if (getState() != ACTIVE) return;
 		backoff.increment();
 		for (Pair<TransportProperties, ConnectionHandler> p : properties) {
 			connect(p.getFirst(), p.getSecond());
@@ -535,7 +630,7 @@ abstract class TorPlugin implements DuplexPlugin, EventHandler, EventListener {
 	}
 
 	private void connect(TransportProperties p, ConnectionHandler h) {
-		ioExecutor.execute(() -> {
+		wakefulIoExecutor.execute(() -> {
 			DuplexTransportConnection d = createConnection(p);
 			if (d != null) {
 				backoff.reset();
@@ -546,13 +641,16 @@ abstract class TorPlugin implements DuplexPlugin, EventHandler, EventListener {
 
 	@Override
 	public DuplexTransportConnection createConnection(TransportProperties p) {
-		if (!isRunning()) return null;
+		if (getState() != ACTIVE) return null;
-		String bestOnion = null;
+		// TODO: Remove support for v2 hidden services after a reasonable
+		// migration period (migration started 2020-06-30)
+		String bestOnion = null, version = null;
 		String onion2 = p.get(PROP_ONION_V2);
 		String onion3 = p.get(PROP_ONION_V3);
 		if (!isNullOrEmpty(onion2)) {
 			if (ONION_V2.matcher(onion2).matches()) {
 				bestOnion = onion2;
+				version = "v2";
 			} else {
 				// Don't scrub the address so we can find the problem
 				if (LOG.isLoggable(INFO))
@@ -562,6 +660,7 @@ abstract class TorPlugin implements DuplexPlugin, EventHandler, EventListener {
 		if (!isNullOrEmpty(onion3)) {
 			if (ONION_V3.matcher(onion3).matches()) {
 				bestOnion = onion3;
+				version = "v3";
 			} else {
 				// Don't scrub the address so we can find the problem
 				if (LOG.isLoggable(INFO))
@@ -571,17 +670,21 @@ abstract class TorPlugin implements DuplexPlugin, EventHandler, EventListener {
 		if (bestOnion == null) return null;
 		Socket s = null;
 		try {
-			if (LOG.isLoggable(INFO))
+			if (LOG.isLoggable(INFO)) {
-				LOG.info("Connecting to " + scrubOnion(bestOnion));
+				LOG.info("Connecting to " + version + " "
+						+ scrubOnion(bestOnion));
+			}
 			s = torSocketFactory.createSocket(bestOnion + ".onion", 80);
 			s.setSoTimeout(socketTimeout);
-			if (LOG.isLoggable(INFO))
+			if (LOG.isLoggable(INFO)) {
-				LOG.info("Connected to " + scrubOnion(bestOnion));
+				LOG.info("Connected to " + version + " "
+						+ scrubOnion(bestOnion));
+			}
 			return new TorTransportConnection(this, s);
 		} catch (IOException e) {
 			if (LOG.isLoggable(INFO)) {
-				LOG.info("Could not connect to " + scrubOnion(bestOnion)
+				LOG.info("Could not connect to " + version + " "
-						+ ": " + e.toString());
+						+ scrubOnion(bestOnion) + ": " + e.toString());
 			}
 			tryToClose(s, LOG, WARNING);
 			return null;
@@ -634,8 +737,8 @@ abstract class TorPlugin implements DuplexPlugin, EventHandler, EventListener {
 								new TorTransportConnection(this, s));
 					}
 				} catch (IOException e) {
-					// This is expected when the socket is closed
+					// This is expected when the server socket is closed
-					if (LOG.isLoggable(INFO)) LOG.info(e.toString());
+					LOG.info("Rendezvous server socket closed");
 				}
 			});
 			Map<Integer, String> portLines =
@@ -663,10 +766,9 @@ abstract class TorPlugin implements DuplexPlugin, EventHandler, EventListener {
 	@Override
 	public void circuitStatus(String status, String id, String path) {
 		if (status.equals("BUILT") &&
-				connectionStatus.getAndSetCircuitBuilt()) {
+				state.getAndSetCircuitBuilt()) {
 			LOG.info("First circuit built");
 			backoff.reset();
-			if (isRunning()) callback.transportEnabled();
 		}
 	}
 
@@ -697,16 +799,23 @@ 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%")) {
-			connectionStatus.setBootstrapped();
+			state.setBootstrapped();
 			backoff.reset();
-			if (isRunning()) callback.transportEnabled();
 		}
 	}
 
 	@Override
 	public void unrecognized(String type, String msg) {
-		if (type.equals("HS_DESC") && msg.startsWith("UPLOADED"))
+		if (type.equals("HS_DESC") && msg.startsWith("UPLOADED")) {
-			LOG.info("Descriptor uploaded");
+			if (LOG.isLoggable(INFO)) {
+				String[] words = msg.split(" ");
+				if (words.length > 1 && ONION_V3.matcher(words[1]).matches()) {
+					LOG.info("V3 descriptor uploaded");
+				} else {
+					LOG.info("V2 descriptor uploaded");
+				}
+			}
+		}
 	}
 
 	@Override
@@ -736,7 +845,7 @@ abstract class TorPlugin implements DuplexPlugin, EventHandler, EventListener {
 	private void disableNetwork() {
 		connectionStatusExecutor.execute(() -> {
 			try {
-				enableNetwork(false);
+				if (state.isTorRunning()) enableNetwork(false);
 			} catch (IOException ex) {
 				logException(LOG, WARNING, ex);
 			}
@@ -746,63 +855,90 @@ abstract class TorPlugin implements DuplexPlugin, EventHandler, EventListener {
 	private void updateConnectionStatus(NetworkStatus status,
 			boolean charging) {
 		connectionStatusExecutor.execute(() -> {
-			if (!running) return;
+			if (!state.isTorRunning()) 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,
+					DEFAULT_PREF_PLUGIN_ENABLE);
 			int network = settings.getInt(PREF_TOR_NETWORK,
-					PREF_TOR_NETWORK_AUTOMATIC);
+					DEFAULT_PREF_TOR_NETWORK);
-			boolean useMobile = settings.getBoolean(PREF_TOR_MOBILE, true);
+			boolean useMobile = settings.getBoolean(PREF_TOR_MOBILE,
+					DEFAULT_PREF_TOR_MOBILE);
 			boolean onlyWhenCharging =
-					settings.getBoolean(PREF_TOR_ONLY_WHEN_CHARGING, false);
+					settings.getBoolean(PREF_TOR_ONLY_WHEN_CHARGING,
+							DEFAULT_PREF_TOR_ONLY_WHEN_CHARGING);
 			boolean bridgesWork = circumventionProvider.doBridgesWork(country);
 			boolean automatic = network == PREF_TOR_NETWORK_AUTOMATIC;
 
 			if (LOG.isLoggable(INFO)) {
 				LOG.info("Online: " + online + ", wifi: " + wifi);
-				if ("".equals(country)) LOG.info("Country code unknown");
+				if (country.isEmpty()) LOG.info("Country code unknown");
 				else LOG.info("Country code: " + country);
 				LOG.info("Charging: " + charging);
 			}
 
-			try {
+			int reasonsDisabled = 0;
-				if (!online) {
+			boolean enableNetwork = false, enableBridges = false;
-					LOG.info("Disabling network, device is offline");
+			boolean useMeek = false, enableConnectionPadding = false;
-					enableNetwork(false);
+
-				} else if (!charging && onlyWhenCharging) {
+			if (!online) {
-					LOG.info("Disabling network, device is on battery");
+				LOG.info("Disabling network, device is offline");
-					enableNetwork(false);
+			} else {
-				} else if (network == PREF_TOR_NETWORK_NEVER ||
+				if (!enabledByUser) {
-						(!useMobile && !wifi)) {
+					LOG.info("User has disabled Tor");
-					LOG.info("Disabling network, device is using mobile data");
+					reasonsDisabled |= REASON_USER;
-					enableNetwork(false);
+				}
-				} else if (automatic && blocked && !bridgesWork) {
+				if (!charging && onlyWhenCharging) {
-					LOG.info("Disabling network, country is blocked");
+					LOG.info("Configured not to use battery");
-					enableNetwork(false);
+					reasonsDisabled |= REASON_BATTERY;
-				} else if (network == PREF_TOR_NETWORK_WITH_BRIDGES ||
+				}
-						(automatic && bridgesWork)) {
+				if (!useMobile && !wifi) {
-					if (circumventionProvider.needsMeek(country)) {
+					LOG.info("Configured not to use mobile data");
-						LOG.info("Enabling network, using meek bridges");
+					reasonsDisabled |= REASON_MOBILE_DATA;
-						enableBridges(true, true);
+				}
+				if (automatic && blocked && !bridgesWork) {
+					LOG.info("Country is blocked");
+					reasonsDisabled |= REASON_COUNTRY_BLOCKED;
+				}
+
+				if (reasonsDisabled != 0) {
+					LOG.info("Disabling network due to settings");
+				} else {
+					LOG.info("Enabling network");
+					enableNetwork = true;
+					if (network == PREF_TOR_NETWORK_WITH_BRIDGES ||
+							(automatic && bridgesWork)) {
+						if (circumventionProvider.needsMeek(country)) {
+							LOG.info("Using meek bridges");
+							enableBridges = true;
+							useMeek = true;
+						} else {
+							LOG.info("Using obfs4 bridges");
+							enableBridges = true;
+						}
 					} else {
-						LOG.info("Enabling network, using obfs4 bridges");
+						LOG.info("Not using bridges");
-						enableBridges(true, false);
+					}
+					if (wifi && charging) {
+						LOG.info("Enabling connection padding");
+						enableConnectionPadding = true;
+					} else {
+						LOG.info("Disabling connection padding");
 					}
-					enableNetwork(true);
-				} else {
-					LOG.info("Enabling network, not using bridges");
-					enableBridges(false, false);
-					enableNetwork(true);
 				}
-				if (online && wifi && charging) {
+			}
-					LOG.info("Enabling connection padding");
+
-					enableConnectionPadding(true);
+			state.setReasonsDisabled(reasonsDisabled);
-				} else {
+
-					LOG.info("Disabling connection padding");
+			try {
-					enableConnectionPadding(false);
+				if (enableNetwork) {
+					enableBridges(enableBridges, useMeek);
+					enableConnectionPadding(enableConnectionPadding);
 				}
+				enableNetwork(enableNetwork);
 			} catch (IOException e) {
 				logException(LOG, WARNING, e);
 			}
@@ -810,33 +946,96 @@ abstract class TorPlugin implements DuplexPlugin, EventHandler, EventListener {
 	}
 
 	private void enableConnectionPadding(boolean enable) throws IOException {
-		if (!running) return;
 		controlConnection.setConf("ConnectionPadding", enable ? "1" : "0");
 	}
 
-	private static class ConnectionStatus {
+	@ThreadSafe
+	@NotNullByDefault
+	protected class PluginState {
 
-		// All of the following are locking: this
+		@GuardedBy("this")
-		private boolean networkEnabled = false;
+		private boolean started = false,
-		private boolean bootstrapped = false, circuitBuilt = false;
+				stopped = false,
+				networkInitialised = false,
+				networkEnabled = false,
+				bootstrapped = false,
+				circuitBuilt = false,
+				settingsChecked = false;
 
-		private synchronized void setBootstrapped() {
+		@GuardedBy("this")
-			bootstrapped = true;
+		private int reasonsDisabled = 0;
+
+		@GuardedBy("this")
+		@Nullable
+		private ServerSocket serverSocket = null;
+
+		synchronized void setStarted() {
+			started = true;
+			callback.pluginStateChanged(getState());
 		}
 
-		private synchronized boolean getAndSetCircuitBuilt() {
+		synchronized boolean isTorRunning() {
+			return started && !stopped;
+		}
+
+		@Nullable
+		synchronized ServerSocket setStopped() {
+			stopped = true;
+			ServerSocket ss = serverSocket;
+			serverSocket = null;
+			callback.pluginStateChanged(getState());
+			return ss;
+		}
+
+		synchronized void setBootstrapped() {
+			bootstrapped = true;
+			callback.pluginStateChanged(getState());
+		}
+
+		synchronized boolean getAndSetCircuitBuilt() {
 			boolean firstCircuit = !circuitBuilt;
 			circuitBuilt = true;
+			callback.pluginStateChanged(getState());
 			return firstCircuit;
 		}
 
-		private synchronized void enableNetwork(boolean enable) {
+		synchronized void enableNetwork(boolean enable) {
+			networkInitialised = true;
 			networkEnabled = enable;
 			if (!enable) circuitBuilt = false;
+			callback.pluginStateChanged(getState());
 		}
 
-		private synchronized boolean isConnected() {
+		synchronized void setReasonsDisabled(int reasonsDisabled) {
-			return networkEnabled && bootstrapped && circuitBuilt;
+			settingsChecked = true;
+			this.reasonsDisabled = reasonsDisabled;
+			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 || !settingsChecked) {
+				return STARTING_STOPPING;
+			}
+			if (reasonsDisabled != 0) return DISABLED;
+			if (!networkInitialised) return ENABLING;
+			if (!networkEnabled) return INACTIVE;
+			return bootstrapped && circuitBuilt ? ACTIVE : ENABLING;
+		}
+
+		synchronized int getReasonsDisabled() {
+			return getState() == DISABLED ? reasonsDisabled : 0;
 		}
 	}
 }

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

@@ -18,6 +18,7 @@ import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
 import org.briarproject.bramble.api.plugin.TransportId;
 import org.briarproject.bramble.api.properties.TransportProperties;
 import org.briarproject.bramble.api.properties.TransportPropertyManager;
+import org.briarproject.bramble.api.properties.event.RemoteTransportPropertiesUpdatedEvent;
 import org.briarproject.bramble.api.sync.Group;
 import org.briarproject.bramble.api.sync.Group.Visibility;
 import org.briarproject.bramble.api.sync.GroupId;
@@ -30,6 +31,7 @@ import org.briarproject.bramble.api.versioning.ClientVersioningManager;
 import org.briarproject.bramble.api.versioning.ClientVersioningManager.ClientVersioningHook;
 
 import java.util.HashMap;
+import java.util.Iterator;
 import java.util.Map;
 import java.util.Map.Entry;
 
@@ -41,6 +43,8 @@ import static org.briarproject.bramble.api.properties.TransportPropertyConstants
 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.TransportPropertyConstants.REFLECTED_PROPERTY_PREFIX;
+import static org.briarproject.bramble.util.StringUtils.isNullOrEmpty;
 
 @Immutable
 @NotNullByDefault
@@ -127,8 +131,10 @@ class TransportPropertyManagerImpl implements TransportPropertyManager,
 					// We've already received a newer update - delete this one
 					db.deleteMessage(txn, m.getId());
 					db.deleteMessageMetadata(txn, m.getId());
+					return false;
 				}
 			}
+			txn.attach(new RemoteTransportPropertiesUpdatedEvent(t));
 		} catch (FormatException e) {
 			throw new InvalidMessageException(e);
 		}
@@ -151,15 +157,27 @@ class TransportPropertyManagerImpl implements TransportPropertyManager,
 		if (props.isEmpty()) return;
 		try {
 			db.transaction(false, txn -> {
-				Group g = getContactGroup(db.getContact(txn, c));
+				Contact contact = db.getContact(txn, c);
+				Group g = getContactGroup(contact);
 				BdfDictionary meta = clientHelper.getGroupMetadataAsDictionary(
 						txn, g.getId());
 				BdfDictionary discovered =
 						meta.getOptionalDictionary(GROUP_KEY_DISCOVERED);
-				if (discovered == null) discovered = new BdfDictionary();
+				BdfDictionary merged;
-				discovered.putAll(props);
+				boolean changed;
-				meta.put(GROUP_KEY_DISCOVERED, discovered);
+				if (discovered == null) {
-				clientHelper.mergeGroupMetadata(txn, g.getId(), meta);
+					merged = new BdfDictionary(props);
+					changed = true;
+				} else {
+					merged = new BdfDictionary(discovered);
+					merged.putAll(props);
+					changed = !merged.equals(discovered);
+				}
+				if (changed) {
+					meta.put(GROUP_KEY_DISCOVERED, merged);
+					clientHelper.mergeGroupMetadata(txn, g.getId(), meta);
+					updateLocalProperties(txn, contact, t);
+				}
 			});
 		} catch (FormatException e) {
 			throw new DbException(e);
@@ -224,6 +242,24 @@ class TransportPropertyManagerImpl implements TransportPropertyManager,
 		});
 	}
 
+	private void updateLocalProperties(Transaction txn, Contact c,
+			TransportId t) throws DbException {
+		try {
+			TransportProperties local;
+			LatestUpdate latest = findLatest(txn, localGroup.getId(), t, true);
+			if (latest == null) {
+				local = new TransportProperties();
+			} else {
+				BdfList message = clientHelper.getMessageAsList(txn,
+						latest.messageId);
+				local = parseProperties(message);
+			}
+			storeLocalProperties(txn, c, t, local);
+		} catch (FormatException e) {
+			throw new DbException(e);
+		}
+	}
+
 	private TransportProperties getRemoteProperties(Transaction txn, Contact c,
 			TransportId t) throws DbException {
 		Group g = getContactGroup(c);
@@ -272,14 +308,22 @@ class TransportPropertyManagerImpl implements TransportPropertyManager,
 				LatestUpdate latest = findLatest(txn, localGroup.getId(), t,
 						true);
 				if (latest == null) {
-					merged = p;
+					merged = new TransportProperties(p);
+					Iterator<String> it = merged.values().iterator();
+					while (it.hasNext()) {
+						if (isNullOrEmpty(it.next())) it.remove();
+					}
 					changed = true;
 				} else {
 					BdfList message = clientHelper.getMessageAsList(txn,
 							latest.messageId);
 					TransportProperties old = parseProperties(message);
 					merged = new TransportProperties(old);
-					merged.putAll(p);
+					for (Entry<String, String> e : p.entrySet()) {
+						String key = e.getKey(), value = e.getValue();
+						if (isNullOrEmpty(value)) merged.remove(key);
+						else merged.put(key, value);
+					}
 					changed = !merged.equals(old);
 				}
 				if (changed) {
@@ -288,18 +332,10 @@ class TransportPropertyManagerImpl implements TransportPropertyManager,
 					storeMessage(txn, localGroup.getId(), t, merged, version,
 							true, false);
 					// Delete the previous update, if any
-					if (latest != null)
+					if (latest != null) db.removeMessage(txn, latest.messageId);
-						db.removeMessage(txn, latest.messageId);
 					// Store the merged properties in each contact's group
 					for (Contact c : db.getContacts(txn)) {
-						Group g = getContactGroup(c);
+						storeLocalProperties(txn, c, t, merged);
-						latest = findLatest(txn, g.getId(), t, true);
-						version = latest == null ? 1 : latest.version + 1;
-						storeMessage(txn, g.getId(), t, merged, version,
-								true, true);
-						// Delete the previous update, if any
-						if (latest != null)
-							db.removeMessage(txn, latest.messageId);
 					}
 				}
 			});
@@ -308,6 +344,34 @@ class TransportPropertyManagerImpl implements TransportPropertyManager,
 		}
 	}
 
+	private void storeLocalProperties(Transaction txn, Contact c,
+			TransportId t, TransportProperties p)
+			throws DbException, FormatException {
+		Group g = getContactGroup(c);
+		LatestUpdate latest = findLatest(txn, g.getId(), t, true);
+		long version = latest == null ? 1 : latest.version + 1;
+		// Reflect any remote properties we've discovered
+		BdfDictionary meta = clientHelper.getGroupMetadataAsDictionary(txn,
+				g.getId());
+		BdfDictionary discovered =
+				meta.getOptionalDictionary(GROUP_KEY_DISCOVERED);
+		TransportProperties combined;
+		if (discovered == null) {
+			combined = p;
+		} else {
+			combined = new TransportProperties(p);
+			TransportProperties d = clientHelper
+					.parseAndValidateTransportProperties(discovered);
+			for (Entry<String, String> e : d.entrySet()) {
+				String key = REFLECTED_PROPERTY_PREFIX + e.getKey();
+				combined.put(key, e.getValue());
+			}
+		}
+		storeMessage(txn, g.getId(), t, combined, version, true, true);
+		// Delete the previous update, if any
+		if (latest != null) db.removeMessage(txn, latest.messageId);
+	}
+
 	private Group getContactGroup(Contact c) {
 		return contactGroupFactory.createContactGroup(CLIENT_ID,
 				MAJOR_VERSION, c);

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.TransportDisabledEvent;
+import org.briarproject.bramble.api.plugin.event.TransportActiveEvent;
-import org.briarproject.bramble.api.plugin.event.TransportEnabledEvent;
+import org.briarproject.bramble.api.plugin.event.TransportInactiveEvent;
 import org.briarproject.bramble.api.properties.TransportProperties;
 import org.briarproject.bramble.api.rendezvous.KeyMaterialSource;
 import org.briarproject.bramble.api.rendezvous.RendezvousEndpoint;
@@ -41,7 +41,9 @@ import org.briarproject.bramble.api.rendezvous.event.RendezvousConnectionClosedE
 import org.briarproject.bramble.api.rendezvous.event.RendezvousConnectionOpenedEvent;
 import org.briarproject.bramble.api.rendezvous.event.RendezvousPollEvent;
 import org.briarproject.bramble.api.system.Clock;
-import org.briarproject.bramble.api.system.Scheduler;
+import org.briarproject.bramble.api.system.TaskScheduler;
+import org.briarproject.bramble.api.system.TaskScheduler.Cancellable;
+import org.briarproject.bramble.api.system.Wakeful;
 
 import java.security.GeneralSecurityException;
 import java.util.ArrayList;
@@ -52,7 +54,6 @@ import java.util.Map;
 import java.util.Map.Entry;
 import java.util.concurrent.ConcurrentHashMap;
 import java.util.concurrent.Executor;
-import java.util.concurrent.ScheduledExecutorService;
 import java.util.concurrent.atomic.AtomicBoolean;
 import java.util.logging.Logger;
 
@@ -68,6 +69,7 @@ import static org.briarproject.bramble.api.contact.PendingContactState.ADDING_CO
 import static org.briarproject.bramble.api.contact.PendingContactState.FAILED;
 import static org.briarproject.bramble.api.contact.PendingContactState.OFFLINE;
 import static org.briarproject.bramble.api.contact.PendingContactState.WAITING_FOR_CONNECTION;
+import static org.briarproject.bramble.api.nullsafety.NullSafety.requireNonNull;
 import static org.briarproject.bramble.api.nullsafety.NullSafety.requireNull;
 import static org.briarproject.bramble.rendezvous.RendezvousConstants.POLLING_INTERVAL_MS;
 import static org.briarproject.bramble.rendezvous.RendezvousConstants.RENDEZVOUS_TIMEOUT_MS;
@@ -80,7 +82,7 @@ class RendezvousPollerImpl implements RendezvousPoller, Service, EventListener {
 	private static final Logger LOG =
 			getLogger(RendezvousPollerImpl.class.getName());
 
-	private final ScheduledExecutorService scheduler;
+	private final TaskScheduler scheduler;
 	private final DatabaseComponent db;
 	private final IdentityManager identityManager;
 	private final TransportCrypto transportCrypto;
@@ -102,10 +104,12 @@ class RendezvousPollerImpl implements RendezvousPoller, Service, EventListener {
 			new HashMap<>();
 	@Nullable
 	private KeyPair handshakeKeyPair = null;
+	@Nullable
+	private Cancellable pollTask = null;
 
 	@Inject
 	RendezvousPollerImpl(@IoExecutor Executor ioExecutor,
-			@Scheduler ScheduledExecutorService scheduler,
+			TaskScheduler scheduler,
 			DatabaseComponent db,
 			IdentityManager identityManager,
 			TransportCrypto transportCrypto,
@@ -144,8 +148,6 @@ class RendezvousPollerImpl implements RendezvousPoller, Service, EventListener {
 		} catch (DbException e) {
 			throw new ServiceException(e);
 		}
-		scheduler.scheduleAtFixedRate(this::poll, POLLING_INTERVAL_MS,
-				POLLING_INTERVAL_MS, MILLISECONDS);
 	}
 
 	@EventExecutor
@@ -186,6 +188,12 @@ class RendezvousPollerImpl implements RendezvousPoller, Service, EventListener {
 			}
 			if (cs.numEndpoints == 0) broadcastState(p.getId(), OFFLINE);
 			else broadcastState(p.getId(), WAITING_FOR_CONNECTION);
+			if (cryptoStates.size() == 1) {
+				LOG.info("Starting poller");
+				requireNull(pollTask);
+				pollTask = scheduler.scheduleWithFixedDelay(this::poll, worker,
+						POLLING_INTERVAL_MS, POLLING_INTERVAL_MS, MILLISECONDS);
+			}
 		} catch (DbException | GeneralSecurityException e) {
 			logException(LOG, WARNING, e);
 		}
@@ -205,12 +213,12 @@ class RendezvousPollerImpl implements RendezvousPoller, Service, EventListener {
 		return plugin.createRendezvousEndpoint(k, cs.alice, h);
 	}
 
-	@Scheduler
+	// Worker
+	@Wakeful
 	private void poll() {
-		worker.execute(() -> {
+		LOG.info("Polling");
-			removeExpiredPendingContacts();
+		removeExpiredPendingContacts();
-			for (PluginState ps : pluginStates.values()) poll(ps);
+		for (PluginState ps : pluginStates.values()) poll(ps);
-		});
 	}
 
 	// Worker
@@ -235,9 +243,15 @@ class RendezvousPollerImpl implements RendezvousPoller, Service, EventListener {
 			RendezvousEndpoint endpoint = ps.endpoints.remove(p);
 			if (endpoint != null) tryToClose(endpoint, LOG, INFO);
 		}
+		if (cryptoStates.isEmpty()) {
+			LOG.info("Stopping poller");
+			requireNonNull(pollTask).cancel();
+			pollTask = null;
+		}
 	}
 
 	// Worker
+	@Wakeful
 	private void poll(PluginState ps) {
 		if (ps.endpoints.isEmpty()) return;
 		TransportId t = ps.plugin.getId();
@@ -269,11 +283,11 @@ class RendezvousPollerImpl implements RendezvousPoller, Service, EventListener {
 		} else if (e instanceof PendingContactRemovedEvent) {
 			PendingContactRemovedEvent p = (PendingContactRemovedEvent) e;
 			removePendingContactAsync(p.getId());
-		} else if (e instanceof TransportEnabledEvent) {
+		} else if (e instanceof TransportActiveEvent) {
-			TransportEnabledEvent t = (TransportEnabledEvent) e;
+			TransportActiveEvent t = (TransportActiveEvent) e;
 			addTransportAsync(t.getTransportId());
-		} else if (e instanceof TransportDisabledEvent) {
+		} else if (e instanceof TransportInactiveEvent) {
-			TransportDisabledEvent t = (TransportDisabledEvent) e;
+			TransportInactiveEvent t = (TransportInactiveEvent) 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.TransportEnabledEvent;
+import org.briarproject.bramble.api.plugin.event.TransportActiveEvent;
 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 TransportEnabledEvent) {
+		if (e instanceof TransportActiveEvent) {
-			TransportEnabledEvent t = (TransportEnabledEvent) e;
+			TransportActiveEvent t = (TransportActiveEvent) e;
 			if (t.getTransportId().equals(TorConstants.ID))
 				ioExecutor.execute(this::sendReports);
 		}

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

@@ -12,6 +12,7 @@ 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.plugin.event.TransportInactiveEvent;
 import org.briarproject.bramble.api.sync.Ack;
 import org.briarproject.bramble.api.sync.Message;
 import org.briarproject.bramble.api.sync.Offer;
@@ -238,6 +239,9 @@ class DuplexOutgoingSession implements SyncSession, EventListener {
 		} else if (e instanceof CloseSyncConnectionsEvent) {
 			CloseSyncConnectionsEvent c = (CloseSyncConnectionsEvent) e;
 			if (c.getTransportId().equals(transportId)) interrupt();
+		} else if (e instanceof TransportInactiveEvent) {
+			TransportInactiveEvent t = (TransportInactiveEvent) e;
+			if (t.getTransportId().equals(transportId)) interrupt();
 		}
 	}
 

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

@@ -12,6 +12,7 @@ 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.plugin.event.TransportInactiveEvent;
 import org.briarproject.bramble.api.sync.Ack;
 import org.briarproject.bramble.api.sync.Message;
 import org.briarproject.bramble.api.sync.SyncRecordWriter;
@@ -131,6 +132,9 @@ class SimplexOutgoingSession implements SyncSession, EventListener {
 		} else if (e instanceof CloseSyncConnectionsEvent) {
 			CloseSyncConnectionsEvent c = (CloseSyncConnectionsEvent) e;
 			if (c.getTransportId().equals(transportId)) interrupt();
+		} else if (e instanceof TransportInactiveEvent) {
+			TransportInactiveEvent t = (TransportInactiveEvent) e;
+			if (t.getTransportId().equals(transportId)) interrupt();
 		}
 	}
 

bramble-core/src/main/java/org/briarproject/bramble/sync/validation/ValidationManagerImpl.java

@@ -35,6 +35,7 @@ import java.util.concurrent.Executor;
 import java.util.concurrent.atomic.AtomicBoolean;
 import java.util.logging.Logger;
 
+import javax.annotation.Nullable;
 import javax.annotation.concurrent.ThreadSafe;
 import javax.inject.Inject;
 
@@ -124,8 +125,7 @@ class ValidationManagerImpl implements ValidationManager, Service,
 				Group g = db.getGroup(txn, m.getGroupId());
 				return new Pair<>(m, g);
 			});
-			validateMessageAsync(mg.getFirst(), mg.getSecond());
+			validateMessageAsync(mg.getFirst(), mg.getSecond(), unvalidated);
-			validateNextMessageAsync(unvalidated);
 		} catch (NoSuchMessageException e) {
 			LOG.info("Message removed before validation");
 			validateNextMessageAsync(unvalidated);
@@ -213,12 +213,14 @@ class ValidationManagerImpl implements ValidationManager, Service,
 		}
 	}
 
-	private void validateMessageAsync(Message m, Group g) {
+	private void validateMessageAsync(Message m, Group g,
-		validationExecutor.execute(() -> validateMessage(m, g));
+			@Nullable Queue<MessageId> unvalidated) {
+		validationExecutor.execute(() -> validateMessage(m, g, unvalidated));
 	}
 
 	@ValidationExecutor
-	private void validateMessage(Message m, Group g) {
+	private void validateMessage(Message m, Group g,
+			@Nullable Queue<MessageId> unvalidated) {
 		ClientMajorVersion cv =
 				new ClientMajorVersion(g.getClientId(), g.getMajorVersion());
 		MessageValidator v = validators.get(cv);
@@ -234,6 +236,8 @@ class ValidationManagerImpl implements ValidationManager, Service,
 				Queue<MessageId> invalidate = new LinkedList<>();
 				invalidate.add(m.getId());
 				invalidateNextMessageAsync(invalidate);
+			} finally {
+				if (unvalidated != null) validateNextMessageAsync(unvalidated);
 			}
 		}
 	}
@@ -440,7 +444,7 @@ class ValidationManagerImpl implements ValidationManager, Service,
 		try {
 			Group g = db.transactionWithResult(true, txn ->
 					db.getGroup(txn, m.getGroupId()));
-			validateMessageAsync(m, g);
+			validateMessageAsync(m, g, null);
 		} catch (NoSuchGroupException e) {
 			LOG.info("Group removed before validation");
 		} catch (DbException e) {

bramble-core/src/main/java/org/briarproject/bramble/system/ClockModule.java

@@ -0,0 +1,15 @@
+package org.briarproject.bramble.system;
+
+import org.briarproject.bramble.api.system.Clock;
+
+import dagger.Module;
+import dagger.Provides;
+
+@Module
+public class ClockModule {
+
+	@Provides
+	Clock provideClock() {
+		return new SystemClock();
+	}
+}

bramble-core/src/main/java/org/briarproject/bramble/system/DefaultTaskSchedulerModule.java

@@ -1,8 +1,7 @@
 package org.briarproject.bramble.system;
 
 import org.briarproject.bramble.api.lifecycle.LifecycleManager;
-import org.briarproject.bramble.api.system.Clock;
+import org.briarproject.bramble.api.system.TaskScheduler;
-import org.briarproject.bramble.api.system.Scheduler;
 
 import java.util.concurrent.RejectedExecutionHandler;
 import java.util.concurrent.ScheduledExecutorService;
@@ -15,34 +14,26 @@ import dagger.Module;
 import dagger.Provides;
 
 @Module
-public class SystemModule {
+public class DefaultTaskSchedulerModule {
 
 	public static class EagerSingletons {
 		@Inject
-		@Scheduler
+		TaskScheduler scheduler;
-		ScheduledExecutorService scheduledExecutorService;
 	}
 
-	private final ScheduledExecutorService scheduler;
+	private final ScheduledExecutorService scheduledExecutorService;
 
-	public SystemModule() {
+	public DefaultTaskSchedulerModule() {
 		// Discard tasks that are submitted during shutdown
 		RejectedExecutionHandler policy =
 				new ScheduledThreadPoolExecutor.DiscardPolicy();
-		scheduler = new ScheduledThreadPoolExecutor(1, policy);
+		scheduledExecutorService = new ScheduledThreadPoolExecutor(1, policy);
-	}
-
-	@Provides
-	Clock provideClock() {
-		return new SystemClock();
 	}
 
 	@Provides
 	@Singleton
-	@Scheduler
+	TaskScheduler provideTaskScheduler(LifecycleManager lifecycleManager) {
-	ScheduledExecutorService provideScheduledExecutorService(
+		lifecycleManager.registerForShutdown(scheduledExecutorService);
-			LifecycleManager lifecycleManager) {
+		return new TaskSchedulerImpl(scheduledExecutorService);
-		lifecycleManager.registerForShutdown(scheduler);
-		return scheduler;
 	}
 }

bramble-core/src/main/java/org/briarproject/bramble/system/DefaultWakefulIoExecutorModule.java

@@ -0,0 +1,23 @@
+package org.briarproject.bramble.system;
+
+import org.briarproject.bramble.api.lifecycle.IoExecutor;
+import org.briarproject.bramble.api.system.WakefulIoExecutor;
+
+import java.util.concurrent.Executor;
+
+import dagger.Module;
+import dagger.Provides;
+
+/**
+ * Provides a default implementation of {@link WakefulIoExecutor} for systems
+ * without wake locks.
+ */
+@Module
+public class DefaultWakefulIoExecutorModule {
+
+	@Provides
+	@WakefulIoExecutor
+	Executor provideWakefulIoExecutor(@IoExecutor Executor ioExecutor) {
+		return ioExecutor;
+	}
+}

bramble-core/src/main/java/org/briarproject/bramble/system/TaskSchedulerImpl.java

@@ -0,0 +1,43 @@
+package org.briarproject.bramble.system;
+
+import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
+import org.briarproject.bramble.api.system.TaskScheduler;
+
+import java.util.concurrent.Executor;
+import java.util.concurrent.ScheduledExecutorService;
+import java.util.concurrent.ScheduledFuture;
+import java.util.concurrent.TimeUnit;
+
+import javax.annotation.concurrent.ThreadSafe;
+
+/**
+ * A {@link TaskScheduler} that uses a {@link ScheduledExecutorService}.
+ */
+@ThreadSafe
+@NotNullByDefault
+class TaskSchedulerImpl implements TaskScheduler {
+
+	private final ScheduledExecutorService scheduledExecutorService;
+
+	TaskSchedulerImpl(ScheduledExecutorService scheduledExecutorService) {
+		this.scheduledExecutorService = scheduledExecutorService;
+	}
+
+	@Override
+	public Cancellable schedule(Runnable task, Executor executor, long delay,
+			TimeUnit unit) {
+		Runnable execute = () -> executor.execute(task);
+		ScheduledFuture<?> future =
+				scheduledExecutorService.schedule(execute, delay, unit);
+		return () -> future.cancel(false);
+	}
+
+	@Override
+	public Cancellable scheduleWithFixedDelay(Runnable task, Executor executor,
+			long delay, long interval, TimeUnit unit) {
+		Runnable execute = () -> executor.execute(task);
+		ScheduledFuture<?> future = scheduledExecutorService.
+				scheduleWithFixedDelay(execute, delay, interval, unit);
+		return () -> future.cancel(false);
+	}
+}

bramble-core/src/main/java/org/briarproject/bramble/transport/TransportKeyManagerFactoryImpl.java

@@ -6,10 +6,9 @@ import org.briarproject.bramble.api.db.DatabaseExecutor;
 import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
 import org.briarproject.bramble.api.plugin.TransportId;
 import org.briarproject.bramble.api.system.Clock;
-import org.briarproject.bramble.api.system.Scheduler;
+import org.briarproject.bramble.api.system.TaskScheduler;
 
 import java.util.concurrent.Executor;
-import java.util.concurrent.ScheduledExecutorService;
 
 import javax.annotation.concurrent.Immutable;
 import javax.inject.Inject;
@@ -22,14 +21,15 @@ class TransportKeyManagerFactoryImpl implements
 	private final DatabaseComponent db;
 	private final TransportCrypto transportCrypto;
 	private final Executor dbExecutor;
-	private final ScheduledExecutorService scheduler;
+	private final TaskScheduler scheduler;
 	private final Clock clock;
 
 	@Inject
 	TransportKeyManagerFactoryImpl(DatabaseComponent db,
 			TransportCrypto transportCrypto,
 			@DatabaseExecutor Executor dbExecutor,
-			@Scheduler ScheduledExecutorService scheduler, Clock clock) {
+			TaskScheduler scheduler,
+			Clock clock) {
 		this.db = db;
 		this.transportCrypto = transportCrypto;
 		this.dbExecutor = dbExecutor;

bramble-core/src/main/java/org/briarproject/bramble/transport/TransportKeyManagerImpl.java

@@ -6,12 +6,14 @@ import org.briarproject.bramble.api.contact.PendingContactId;
 import org.briarproject.bramble.api.crypto.SecretKey;
 import org.briarproject.bramble.api.crypto.TransportCrypto;
 import org.briarproject.bramble.api.db.DatabaseComponent;
+import org.briarproject.bramble.api.db.DatabaseExecutor;
 import org.briarproject.bramble.api.db.DbException;
 import org.briarproject.bramble.api.db.Transaction;
 import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
 import org.briarproject.bramble.api.plugin.TransportId;
 import org.briarproject.bramble.api.system.Clock;
-import org.briarproject.bramble.api.system.Scheduler;
+import org.briarproject.bramble.api.system.TaskScheduler;
+import org.briarproject.bramble.api.system.Wakeful;
 import org.briarproject.bramble.api.transport.KeySetId;
 import org.briarproject.bramble.api.transport.StreamContext;
 import org.briarproject.bramble.api.transport.TransportKeySet;
@@ -24,7 +26,6 @@ import java.util.HashMap;
 import java.util.Iterator;
 import java.util.Map;
 import java.util.concurrent.Executor;
-import java.util.concurrent.ScheduledExecutorService;
 import java.util.concurrent.atomic.AtomicBoolean;
 import java.util.concurrent.locks.ReentrantLock;
 import java.util.logging.Logger;
@@ -53,7 +54,7 @@ class TransportKeyManagerImpl implements TransportKeyManager {
 	private final DatabaseComponent db;
 	private final TransportCrypto transportCrypto;
 	private final Executor dbExecutor;
-	private final ScheduledExecutorService scheduler;
+	private final TaskScheduler scheduler;
 	private final Clock clock;
 	private final TransportId transportId;
 	private final long timePeriodLength;
@@ -72,9 +73,12 @@ class TransportKeyManagerImpl implements TransportKeyManager {
 			pendingContactOutContexts = new HashMap<>();
 
 	TransportKeyManagerImpl(DatabaseComponent db,
-			TransportCrypto transportCrypto, Executor dbExecutor,
+			TransportCrypto transportCrypto,
-			@Scheduler ScheduledExecutorService scheduler, Clock clock,
+			Executor dbExecutor,
-			TransportId transportId, long maxLatency) {
+			TaskScheduler scheduler,
+			Clock clock,
+			TransportId transportId,
+			long maxLatency) {
 		this.db = db;
 		this.transportCrypto = transportCrypto;
 		this.dbExecutor = dbExecutor;
@@ -196,17 +200,17 @@ class TransportKeyManagerImpl implements TransportKeyManager {
 
 	private void scheduleKeyUpdate(long now) {
 		long delay = timePeriodLength - now % timePeriodLength;
-		scheduler.schedule((Runnable) this::updateKeys, delay, MILLISECONDS);
+		scheduler.schedule(this::updateKeys, dbExecutor, delay, MILLISECONDS);
 	}
 
+	@DatabaseExecutor
+	@Wakeful
 	private void updateKeys() {
-		dbExecutor.execute(() -> {
+		try {
-			try {
+			db.transaction(false, this::updateKeys);
-				db.transaction(false, this::updateKeys);
+		} catch (DbException e) {
-			} catch (DbException e) {
+			logException(LOG, WARNING, e);
-				logException(LOG, WARNING, e);
+		}
-			}
-		});
 	}
 
 	@Override
@@ -439,6 +443,8 @@ class TransportKeyManagerImpl implements TransportKeyManager {
 		}
 	}
 
+	@DatabaseExecutor
+	@Wakeful
 	private void updateKeys(Transaction txn) throws DbException {
 		long now = clock.currentTimeMillis();
 		lock.lock();

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

@@ -0,0 +1,18 @@
+package org.briarproject.bramble;
+
+import org.briarproject.bramble.system.DefaultTaskSchedulerModule;
+
+public interface BrambleCoreIntegrationTestEagerSingletons
+		extends BrambleCoreEagerSingletons {
+
+	void inject(DefaultTaskSchedulerModule.EagerSingletons init);
+
+	class Helper {
+
+		public static void injectEagerSingletons(
+				BrambleCoreIntegrationTestEagerSingletons c) {
+			BrambleCoreEagerSingletons.Helper.injectEagerSingletons(c);
+			c.inject(new DefaultTaskSchedulerModule.EagerSingletons());
+		}
+	}
+}

bramble-core/src/test/java/org/briarproject/bramble/contact/ContactExchangeIntegrationTest.java

@@ -1,6 +1,6 @@
 package org.briarproject.bramble.contact;
 
-import org.briarproject.bramble.BrambleCoreEagerSingletons;
+import org.briarproject.bramble.BrambleCoreIntegrationTestEagerSingletons;
 import org.briarproject.bramble.api.Pair;
 import org.briarproject.bramble.api.contact.Contact;
 import org.briarproject.bramble.api.contact.ContactManager;
@@ -62,11 +62,13 @@ public class ContactExchangeIntegrationTest extends BrambleTestCase {
 		alice = DaggerContactExchangeIntegrationTestComponent.builder()
 				.testDatabaseConfigModule(
 						new TestDatabaseConfigModule(aliceDir)).build();
-		BrambleCoreEagerSingletons.Helper.injectEagerSingletons(alice);
+		BrambleCoreIntegrationTestEagerSingletons.Helper
+				.injectEagerSingletons(alice);
 		bob = DaggerContactExchangeIntegrationTestComponent.builder()
 				.testDatabaseConfigModule(new TestDatabaseConfigModule(bobDir))
 				.build();
-		BrambleCoreEagerSingletons.Helper.injectEagerSingletons(bob);
+		BrambleCoreIntegrationTestEagerSingletons.Helper
+				.injectEagerSingletons(bob);
 		// Set up the devices and get the identities
 		aliceIdentity = setUp(alice, "Alice");
 		bobIdentity = setUp(bob, "Bob");

bramble-core/src/test/java/org/briarproject/bramble/contact/ContactExchangeIntegrationTestComponent.java

@@ -1,6 +1,6 @@
 package org.briarproject.bramble.contact;
 
-import org.briarproject.bramble.BrambleCoreEagerSingletons;
+import org.briarproject.bramble.BrambleCoreIntegrationTestEagerSingletons;
 import org.briarproject.bramble.BrambleCoreModule;
 import org.briarproject.bramble.api.connection.ConnectionManager;
 import org.briarproject.bramble.api.contact.ContactExchangeManager;
@@ -23,7 +23,7 @@ import dagger.Component;
 		BrambleCoreModule.class
 })
 interface ContactExchangeIntegrationTestComponent
-		extends BrambleCoreEagerSingletons {
+		extends BrambleCoreIntegrationTestEagerSingletons {
 
 	ConnectionManager getConnectionManager();
 

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

@@ -109,8 +109,8 @@ public class PluginManagerImplTest extends BrambleTestCase {
 			oneOf(duplexPlugin).stop();
 		}});
 
-		PluginManagerImpl p = new PluginManagerImpl(ioExecutor, eventBus,
+		PluginManagerImpl p = new PluginManagerImpl(ioExecutor, ioExecutor,
-				pluginConfig, connectionManager, settingsManager,
+				eventBus, pluginConfig, connectionManager, settingsManager,
 				transportPropertyManager);
 
 		// Two plugins should be started and stopped

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

@@ -13,12 +13,14 @@ 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.TransportDisabledEvent;
+import org.briarproject.bramble.api.plugin.event.TransportActiveEvent;
-import org.briarproject.bramble.api.plugin.event.TransportEnabledEvent;
+import org.briarproject.bramble.api.plugin.event.TransportInactiveEvent;
 import org.briarproject.bramble.api.plugin.simplex.SimplexPlugin;
 import org.briarproject.bramble.api.properties.TransportProperties;
 import org.briarproject.bramble.api.properties.TransportPropertyManager;
 import org.briarproject.bramble.api.system.Clock;
+import org.briarproject.bramble.api.system.TaskScheduler;
+import org.briarproject.bramble.api.system.TaskScheduler.Cancellable;
 import org.briarproject.bramble.test.BrambleMockTestCase;
 import org.briarproject.bramble.test.ImmediateExecutor;
 import org.briarproject.bramble.test.RunAction;
@@ -30,8 +32,6 @@ import org.junit.Test;
 import java.security.SecureRandom;
 import java.util.List;
 import java.util.concurrent.Executor;
-import java.util.concurrent.ScheduledExecutorService;
-import java.util.concurrent.ScheduledFuture;
 
 import static java.util.Arrays.asList;
 import static java.util.Collections.emptyList;
@@ -45,8 +45,7 @@ import static org.briarproject.bramble.test.TestUtils.getTransportId;
 
 public class PollerImplTest extends BrambleMockTestCase {
 
-	private final ScheduledExecutorService scheduler =
+	private final TaskScheduler scheduler = context.mock(TaskScheduler.class);
-			context.mock(ScheduledExecutorService.class);
 	private final ConnectionManager connectionManager =
 			context.mock(ConnectionManager.class);
 	private final ConnectionRegistry connectionRegistry =
@@ -56,10 +55,11 @@ public class PollerImplTest extends BrambleMockTestCase {
 	private final TransportPropertyManager transportPropertyManager =
 			context.mock(TransportPropertyManager.class);
 	private final Clock clock = context.mock(Clock.class);
-	private final ScheduledFuture future = context.mock(ScheduledFuture.class);
+	private final Cancellable cancellable = context.mock(Cancellable.class);
 	private final SecureRandom random;
 
 	private final Executor ioExecutor = new ImmediateExecutor();
+	private final Executor wakefulIoExecutor = new ImmediateExecutor();
 	private final TransportId transportId = getTransportId();
 	private final ContactId contactId = getContactId();
 	private final TransportProperties properties = new TransportProperties();
@@ -75,9 +75,9 @@ public class PollerImplTest extends BrambleMockTestCase {
 
 	@Before
 	public void setUp() {
-		poller = new PollerImpl(ioExecutor, scheduler, connectionManager,
+		poller = new PollerImpl(ioExecutor, wakefulIoExecutor, scheduler,
-				connectionRegistry, pluginManager, transportPropertyManager,
+				connectionManager, connectionRegistry, pluginManager,
-				random, clock);
+				transportPropertyManager, random, clock);
 	}
 
 	@Test
@@ -235,8 +235,9 @@ public class PollerImplTest extends BrambleMockTestCase {
 			oneOf(clock).currentTimeMillis();
 			will(returnValue(now));
 			oneOf(scheduler).schedule(with(any(Runnable.class)),
-					with((long) pollingInterval), with(MILLISECONDS));
+					with(ioExecutor), with((long) pollingInterval),
-			will(returnValue(future));
+					with(MILLISECONDS));
+			will(returnValue(cancellable));
 		}});
 
 		poller.eventOccurred(new ConnectionOpenedEvent(contactId, transportId,
@@ -263,8 +264,9 @@ public class PollerImplTest extends BrambleMockTestCase {
 			oneOf(clock).currentTimeMillis();
 			will(returnValue(now));
 			oneOf(scheduler).schedule(with(any(Runnable.class)),
-					with((long) pollingInterval), with(MILLISECONDS));
+					with(ioExecutor), with((long) pollingInterval),
-			will(returnValue(future));
+					with(MILLISECONDS));
+			will(returnValue(cancellable));
 			// Second event
 			// Get the plugin
 			oneOf(pluginManager).getPlugin(transportId);
@@ -305,8 +307,9 @@ public class PollerImplTest extends BrambleMockTestCase {
 			oneOf(clock).currentTimeMillis();
 			will(returnValue(now));
 			oneOf(scheduler).schedule(with(any(Runnable.class)),
-					with((long) pollingInterval), with(MILLISECONDS));
+					with(ioExecutor), with((long) pollingInterval),
-			will(returnValue(future));
+					with(MILLISECONDS));
+			will(returnValue(cancellable));
 			// Second event
 			// Get the plugin
 			oneOf(pluginManager).getPlugin(transportId);
@@ -319,9 +322,10 @@ public class PollerImplTest extends BrambleMockTestCase {
 			will(returnValue(pollingInterval - 2));
 			oneOf(clock).currentTimeMillis();
 			will(returnValue(now + 1));
-			oneOf(future).cancel(false);
+			oneOf(cancellable).cancel();
 			oneOf(scheduler).schedule(with(any(Runnable.class)),
-					with((long) pollingInterval - 2), with(MILLISECONDS));
+					with(ioExecutor), with((long) pollingInterval - 2),
+					with(MILLISECONDS));
 		}});
 
 		poller.eventOccurred(new ConnectionOpenedEvent(contactId, transportId,
@@ -331,7 +335,7 @@ public class PollerImplTest extends BrambleMockTestCase {
 	}
 
 	@Test
-	public void testPollsOnTransportEnabled() throws Exception {
+	public void testPollsOnTransportActivated() throws Exception {
 		DuplexPlugin plugin = context.mock(DuplexPlugin.class);
 
 		context.checking(new Expectations() {{
@@ -346,9 +350,9 @@ public class PollerImplTest extends BrambleMockTestCase {
 			// Schedule a polling task immediately
 			oneOf(clock).currentTimeMillis();
 			will(returnValue(now));
-			oneOf(scheduler).schedule(with(any(Runnable.class)), with(0L),
+			oneOf(scheduler).schedule(with(any(Runnable.class)),
-					with(MILLISECONDS));
+					with(ioExecutor), with(0L), with(MILLISECONDS));
-			will(returnValue(future));
+			will(returnValue(cancellable));
 			will(new RunAction());
 			// Running the polling task schedules the next polling task
 			oneOf(plugin).getPollingInterval();
@@ -358,8 +362,9 @@ public class PollerImplTest extends BrambleMockTestCase {
 			oneOf(clock).currentTimeMillis();
 			will(returnValue(now));
 			oneOf(scheduler).schedule(with(any(Runnable.class)),
-					with((long) (pollingInterval * 0.5)), with(MILLISECONDS));
+					with(ioExecutor), with((long) (pollingInterval * 0.5)),
-			will(returnValue(future));
+					with(MILLISECONDS));
+			will(returnValue(cancellable));
 			// Get the transport properties and connected contacts
 			oneOf(transportPropertyManager).getRemoteProperties(transportId);
 			will(returnValue(singletonMap(contactId, properties)));
@@ -370,7 +375,7 @@ public class PollerImplTest extends BrambleMockTestCase {
 					pairOf(equal(properties), any(ConnectionHandler.class)))));
 		}});
 
-		poller.eventOccurred(new TransportEnabledEvent(transportId));
+		poller.eventOccurred(new TransportActiveEvent(transportId));
 	}
 
 	@Test
@@ -389,9 +394,9 @@ public class PollerImplTest extends BrambleMockTestCase {
 			// Schedule a polling task immediately
 			oneOf(clock).currentTimeMillis();
 			will(returnValue(now));
-			oneOf(scheduler).schedule(with(any(Runnable.class)), with(0L),
+			oneOf(scheduler).schedule(with(any(Runnable.class)),
-					with(MILLISECONDS));
+					with(ioExecutor), with(0L), with(MILLISECONDS));
-			will(returnValue(future));
+			will(returnValue(cancellable));
 			will(new RunAction());
 			// Running the polling task schedules the next polling task
 			oneOf(plugin).getPollingInterval();
@@ -401,8 +406,9 @@ public class PollerImplTest extends BrambleMockTestCase {
 			oneOf(clock).currentTimeMillis();
 			will(returnValue(now));
 			oneOf(scheduler).schedule(with(any(Runnable.class)),
-					with((long) (pollingInterval * 0.5)), with(MILLISECONDS));
+					with(ioExecutor), with((long) (pollingInterval * 0.5)),
-			will(returnValue(future));
+					with(MILLISECONDS));
+			will(returnValue(cancellable));
 			// Get the transport properties and connected contacts
 			oneOf(transportPropertyManager).getRemoteProperties(transportId);
 			will(returnValue(singletonMap(contactId, properties)));
@@ -411,11 +417,11 @@ public class PollerImplTest extends BrambleMockTestCase {
 			// All contacts are connected, so don't poll the plugin
 		}});
 
-		poller.eventOccurred(new TransportEnabledEvent(transportId));
+		poller.eventOccurred(new TransportActiveEvent(transportId));
 	}
 
 	@Test
-	public void testCancelsPollingOnTransportDisabled() {
+	public void testCancelsPollingOnTransportDeactivated() {
 		Plugin plugin = context.mock(Plugin.class);
 
 		context.checking(new Expectations() {{
@@ -430,15 +436,15 @@ public class PollerImplTest extends BrambleMockTestCase {
 			// Schedule a polling task immediately
 			oneOf(clock).currentTimeMillis();
 			will(returnValue(now));
-			oneOf(scheduler).schedule(with(any(Runnable.class)), with(0L),
+			oneOf(scheduler).schedule(with(any(Runnable.class)),
-					with(MILLISECONDS));
+					with(ioExecutor), with(0L), with(MILLISECONDS));
-			will(returnValue(future));
+			will(returnValue(cancellable));
-			// The plugin is disabled before the task runs - cancel the task
+			// The plugin is deactivated before the task runs - cancel the task
-			oneOf(future).cancel(false);
+			oneOf(cancellable).cancel();
 		}});
 
-		poller.eventOccurred(new TransportEnabledEvent(transportId));
+		poller.eventOccurred(new TransportActiveEvent(transportId));
-		poller.eventOccurred(new TransportDisabledEvent(transportId));
+		poller.eventOccurred(new TransportInactiveEvent(transportId));
 	}
 
 	private void expectReschedule(Plugin plugin) {
@@ -455,8 +461,9 @@ public class PollerImplTest extends BrambleMockTestCase {
 			oneOf(clock).currentTimeMillis();
 			will(returnValue(now));
 			oneOf(scheduler).schedule(with(any(Runnable.class)),
-					with((long) pollingInterval), with(MILLISECONDS));
+					with(ioExecutor), with((long) pollingInterval),
-			will(returnValue(future));
+					with(MILLISECONDS));
+			will(returnValue(cancellable));
 		}});
 	}
 

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

@@ -4,6 +4,7 @@ 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;
@@ -21,16 +22,19 @@ import java.net.InetSocketAddress;
 import java.net.NetworkInterface;
 import java.net.ServerSocket;
 import java.net.Socket;
+import java.util.Collection;
 import java.util.concurrent.CountDownLatch;
 import java.util.concurrent.ExecutorService;
 import java.util.concurrent.atomic.AtomicBoolean;
 
 import static java.net.NetworkInterface.getNetworkInterfaces;
+import static java.util.Collections.emptyList;
 import static java.util.Collections.list;
 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;
@@ -49,7 +53,8 @@ public class LanTcpPluginTest extends BrambleTestCase {
 	@Before
 	public void setUp() {
 		callback = new Callback();
-		plugin = new LanTcpPlugin(ioExecutor, backoff, callback, 0, 0, 1000) {
+		plugin = new LanTcpPlugin(ioExecutor, ioExecutor, backoff, callback,
+				0, 0, 1000) {
 			@Override
 			protected boolean canConnectToOwnAddress() {
 				return true;
@@ -302,10 +307,15 @@ public class LanTcpPluginTest extends BrambleTestCase {
 		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 new Settings();
+			return settings;
 		}
 
 		@Override
@@ -313,6 +323,11 @@ public class LanTcpPluginTest extends BrambleTestCase {
 			return local;
 		}
 
+		@Override
+		public Collection<TransportProperties> getRemoteProperties() {
+			return emptyList();
+		}
+
 		@Override
 		public void mergeSettings(Settings s) {
 		}
@@ -324,11 +339,7 @@ public class LanTcpPluginTest extends BrambleTestCase {
 		}
 
 		@Override
-		public void transportEnabled() {
+		public void pluginStateChanged(State newState) {
-		}
-
-		@Override
-		public void transportDisabled() {
 		}
 
 		@Override

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

@@ -8,11 +8,15 @@ import org.briarproject.bramble.api.data.BdfDictionary;
 import org.briarproject.bramble.api.data.BdfEntry;
 import org.briarproject.bramble.api.data.BdfList;
 import org.briarproject.bramble.api.data.MetadataParser;
+import org.briarproject.bramble.api.db.CommitAction;
 import org.briarproject.bramble.api.db.DatabaseComponent;
+import org.briarproject.bramble.api.db.EventAction;
 import org.briarproject.bramble.api.db.Metadata;
 import org.briarproject.bramble.api.db.Transaction;
+import org.briarproject.bramble.api.event.Event;
 import org.briarproject.bramble.api.plugin.TransportId;
 import org.briarproject.bramble.api.properties.TransportProperties;
+import org.briarproject.bramble.api.properties.event.RemoteTransportPropertiesUpdatedEvent;
 import org.briarproject.bramble.api.sync.Group;
 import org.briarproject.bramble.api.sync.GroupId;
 import org.briarproject.bramble.api.sync.Message;
@@ -45,6 +49,7 @@ import static org.briarproject.bramble.test.TestUtils.getMessage;
 import static org.briarproject.bramble.test.TestUtils.getRandomId;
 import static org.junit.Assert.assertEquals;
 import static org.junit.Assert.assertFalse;
+import static org.junit.Assert.assertTrue;
 
 public class TransportPropertyManagerImplTest extends BrambleMockTestCase {
 
@@ -59,23 +64,28 @@ public class TransportPropertyManagerImplTest extends BrambleMockTestCase {
 	private final Clock clock = context.mock(Clock.class);
 
 	private final Group localGroup = getGroup(CLIENT_ID, MAJOR_VERSION);
-	private final BdfDictionary fooPropertiesDict = BdfDictionary.of(
+	private final BdfDictionary fooPropertiesDict, barPropertiesDict;
-			new BdfEntry("fooKey1", "fooValue1"),
+	private final BdfDictionary discoveredPropertiesDict, mergedPropertiesDict;
-			new BdfEntry("fooKey2", "fooValue2")
-	);
-	private final BdfDictionary barPropertiesDict = BdfDictionary.of(
-			new BdfEntry("barKey1", "barValue1"),
-			new BdfEntry("barKey2", "barValue2")
-	);
 	private final TransportProperties fooProperties, barProperties;
+	private final TransportProperties discoveredProperties;
 
-	public TransportPropertyManagerImplTest() throws Exception {
+	public TransportPropertyManagerImplTest() {
 		fooProperties = new TransportProperties();
-		for (String key : fooPropertiesDict.keySet())
+		fooProperties.put("fooKey1", "fooValue1");
-			fooProperties.put(key, fooPropertiesDict.getString(key));
+		fooProperties.put("fooKey2", "fooValue2");
+		fooPropertiesDict = new BdfDictionary(fooProperties);
+
 		barProperties = new TransportProperties();
-		for (String key : barPropertiesDict.keySet())
+		barProperties.put("barKey1", "barValue1");
-			barProperties.put(key, barPropertiesDict.getString(key));
+		barProperties.put("barKey2", "barValue2");
+		barPropertiesDict = new BdfDictionary(barProperties);
+
+		discoveredProperties = new TransportProperties();
+		discoveredProperties.put("fooKey3", "fooValue3");
+		discoveredPropertiesDict = new BdfDictionary(discoveredProperties);
+
+		mergedPropertiesDict = new BdfDictionary(fooProperties);
+		mergedPropertiesDict.put("u:fooKey3", "fooValue3");
 	}
 
 	private TransportPropertyManagerImpl createInstance() {
@@ -221,6 +231,7 @@ public class TransportPropertyManagerImplTest extends BrambleMockTestCase {
 
 		TransportPropertyManagerImpl t = createInstance();
 		assertFalse(t.incomingMessage(txn, message, meta));
+		assertTrue(hasEvent(txn, RemoteTransportPropertiesUpdatedEvent.class));
 	}
 
 	@Test
@@ -259,6 +270,7 @@ public class TransportPropertyManagerImplTest extends BrambleMockTestCase {
 
 		TransportPropertyManagerImpl t = createInstance();
 		assertFalse(t.incomingMessage(txn, message, meta));
+		assertTrue(hasEvent(txn, RemoteTransportPropertiesUpdatedEvent.class));
 	}
 
 	@Test
@@ -292,10 +304,12 @@ public class TransportPropertyManagerImplTest extends BrambleMockTestCase {
 			// The update being delivered (version 3) should be deleted
 			oneOf(db).deleteMessage(txn, message.getId());
 			oneOf(db).deleteMessageMetadata(txn, message.getId());
+			// No event should be broadcast
 		}});
 
 		TransportPropertyManagerImpl t = createInstance();
 		assertFalse(t.incomingMessage(txn, message, meta));
+		assertFalse(hasEvent(txn, RemoteTransportPropertiesUpdatedEvent.class));
 	}
 
 	@Test
@@ -566,6 +580,10 @@ public class TransportPropertyManagerImplTest extends BrambleMockTestCase {
 		Contact contact = getContact();
 		Group contactGroup = getGroup(CLIENT_ID, MAJOR_VERSION);
 
+		// Property with an empty value should be discarded
+		TransportProperties properties = new TransportProperties(fooProperties);
+		properties.put("fooKey3", "");
+
 		context.checking(new DbExpectations() {{
 			oneOf(db).transaction(with(false), withDbRunnable(txn));
 			// There are no existing properties to merge with
@@ -584,10 +602,56 @@ public class TransportPropertyManagerImplTest extends BrambleMockTestCase {
 			oneOf(clientHelper).getMessageMetadataAsDictionary(txn,
 					contactGroup.getId());
 			will(returnValue(emptyMap()));
+			oneOf(clientHelper).getGroupMetadataAsDictionary(txn,
+					contactGroup.getId());
+			will(returnValue(new BdfDictionary()));
 			expectStoreMessage(txn, contactGroup.getId(), "foo",
 					fooPropertiesDict, 1, true, true);
 		}});
 
+		TransportPropertyManagerImpl t = createInstance();
+		t.mergeLocalProperties(new TransportId("foo"), properties);
+	}
+
+	@Test
+	public void testMergingNewPropertiesCreatesUpdateWithReflectedProperties()
+			throws Exception {
+		Transaction txn = new Transaction(null, false);
+		Contact contact = getContact();
+		Group contactGroup = getGroup(CLIENT_ID, MAJOR_VERSION);
+		BdfDictionary contactGroupMeta = BdfDictionary.of(
+				new BdfEntry(GROUP_KEY_DISCOVERED, discoveredPropertiesDict)
+		);
+
+		context.checking(new DbExpectations() {{
+			oneOf(db).transaction(with(false), withDbRunnable(txn));
+			// There are no existing properties to merge with
+			oneOf(clientHelper).getMessageMetadataAsDictionary(txn,
+					localGroup.getId());
+			will(returnValue(emptyMap()));
+			// Store the new properties in the local group, version 1
+			expectStoreMessage(txn, localGroup.getId(), "foo",
+					fooPropertiesDict, 1, true, false);
+			// Store the new properties in each contact's group, version 1
+			oneOf(db).getContacts(txn);
+			will(returnValue(singletonList(contact)));
+			oneOf(contactGroupFactory).createContactGroup(CLIENT_ID,
+					MAJOR_VERSION, contact);
+			will(returnValue(contactGroup));
+			oneOf(clientHelper).getMessageMetadataAsDictionary(txn,
+					contactGroup.getId());
+			will(returnValue(emptyMap()));
+			oneOf(clientHelper).getGroupMetadataAsDictionary(txn,
+					contactGroup.getId());
+			will(returnValue(contactGroupMeta));
+			// Reflect discovered properties
+			oneOf(clientHelper).parseAndValidateTransportProperties(
+					discoveredPropertiesDict);
+			will(returnValue(discoveredProperties));
+			expectStoreMessage(txn, contactGroup.getId(), "foo",
+					mergedPropertiesDict, 1, true, true);
+		}});
+
 		TransportPropertyManagerImpl t = createInstance();
 		t.mergeLocalProperties(new TransportId("foo"), fooProperties);
 	}
@@ -603,6 +667,79 @@ public class TransportPropertyManagerImplTest extends BrambleMockTestCase {
 				new BdfEntry(MSG_KEY_LOCAL, true)
 		);
 		MessageId localGroupUpdateId = new MessageId(getRandomId());
+		Map<MessageId, BdfDictionary> localGroupMessageMetadata =
+				singletonMap(localGroupUpdateId, oldMetadata);
+
+		MessageId contactGroupUpdateId = new MessageId(getRandomId());
+		Map<MessageId, BdfDictionary> contactGroupMessageMetadata =
+				singletonMap(contactGroupUpdateId, oldMetadata);
+
+		TransportProperties oldProperties = new TransportProperties();
+		oldProperties.put("fooKey1", "oldFooValue1");
+		oldProperties.put("fooKey3", "oldFooValue3");
+		BdfDictionary oldPropertiesDict = BdfDictionary.of(
+				new BdfEntry("fooKey1", "oldFooValue1"),
+				new BdfEntry("fooKey3", "oldFooValue3")
+		);
+		BdfList oldUpdate = BdfList.of("foo", 1, oldPropertiesDict);
+
+		// Property assigned an empty value should be removed
+		TransportProperties properties = new TransportProperties(fooProperties);
+		properties.put("fooKey3", "");
+
+		context.checking(new DbExpectations() {{
+			oneOf(db).transaction(with(false), withDbRunnable(txn));
+			// Merge the new properties with the existing properties
+			oneOf(clientHelper).getMessageMetadataAsDictionary(txn,
+					localGroup.getId());
+			will(returnValue(localGroupMessageMetadata));
+			oneOf(clientHelper).getMessageAsList(txn, localGroupUpdateId);
+			will(returnValue(oldUpdate));
+			oneOf(clientHelper).parseAndValidateTransportProperties(
+					oldPropertiesDict);
+			will(returnValue(oldProperties));
+			// Store the merged properties in the local group, version 2
+			expectStoreMessage(txn, localGroup.getId(), "foo",
+					fooPropertiesDict, 2, true, false);
+			// Delete the previous update
+			oneOf(db).removeMessage(txn, localGroupUpdateId);
+			// Store the merged properties in each contact's group, version 2
+			oneOf(db).getContacts(txn);
+			will(returnValue(singletonList(contact)));
+			oneOf(contactGroupFactory).createContactGroup(CLIENT_ID,
+					MAJOR_VERSION, contact);
+			will(returnValue(contactGroup));
+			oneOf(clientHelper).getMessageMetadataAsDictionary(txn,
+					contactGroup.getId());
+			will(returnValue(contactGroupMessageMetadata));
+			oneOf(clientHelper).getGroupMetadataAsDictionary(txn,
+					contactGroup.getId());
+			will(returnValue(new BdfDictionary()));
+			expectStoreMessage(txn, contactGroup.getId(), "foo",
+					fooPropertiesDict, 2, true, true);
+			// Delete the previous update
+			oneOf(db).removeMessage(txn, contactGroupUpdateId);
+		}});
+
+		TransportPropertyManagerImpl t = createInstance();
+		t.mergeLocalProperties(new TransportId("foo"), properties);
+	}
+
+	@Test
+	public void testMergingUpdatedPropertiesCreatesUpdateWithReflectedProperties()
+			throws Exception {
+		Transaction txn = new Transaction(null, false);
+		Contact contact = getContact();
+		Group contactGroup = getGroup(CLIENT_ID, MAJOR_VERSION);
+		BdfDictionary contactGroupMeta = BdfDictionary.of(
+				new BdfEntry(GROUP_KEY_DISCOVERED, discoveredPropertiesDict)
+		);
+		BdfDictionary oldMetadata = BdfDictionary.of(
+				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 =
 				singletonMap(localGroupUpdateId, oldMetadata);
 		MessageId contactGroupUpdateId = new MessageId(getRandomId());
@@ -640,8 +777,15 @@ public class TransportPropertyManagerImplTest extends BrambleMockTestCase {
 			oneOf(clientHelper).getMessageMetadataAsDictionary(txn,
 					contactGroup.getId());
 			will(returnValue(contactGroupMessageMetadata));
+			oneOf(clientHelper).getGroupMetadataAsDictionary(txn,
+					contactGroup.getId());
+			will(returnValue(contactGroupMeta));
+			// Reflect discovered properties
+			oneOf(clientHelper).parseAndValidateTransportProperties(
+					discoveredPropertiesDict);
+			will(returnValue(discoveredProperties));
 			expectStoreMessage(txn, contactGroup.getId(), "foo",
-					fooPropertiesDict, 2, true, true);
+					mergedPropertiesDict, 2, true, true);
 			// Delete the previous update
 			oneOf(db).removeMessage(txn, contactGroupUpdateId);
 		}});
@@ -707,4 +851,15 @@ public class TransportPropertyManagerImplTest extends BrambleMockTestCase {
 					false);
 		}});
 	}
+
+	private boolean hasEvent(Transaction txn,
+			Class<? extends Event> eventClass) {
+		for (CommitAction action : txn.getActions()) {
+			if (action instanceof EventAction) {
+				Event event = ((EventAction) action).getEvent();
+				if (eventClass.isInstance(event)) return true;
+			}
+		}
+		return false;
+	}
 }

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

@@ -17,8 +17,8 @@ import org.briarproject.bramble.api.plugin.ConnectionHandler;
 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.TransportDisabledEvent;
+import org.briarproject.bramble.api.plugin.event.TransportActiveEvent;
-import org.briarproject.bramble.api.plugin.event.TransportEnabledEvent;
+import org.briarproject.bramble.api.plugin.event.TransportInactiveEvent;
 import org.briarproject.bramble.api.properties.TransportProperties;
 import org.briarproject.bramble.api.rendezvous.KeyMaterialSource;
 import org.briarproject.bramble.api.rendezvous.RendezvousEndpoint;
@@ -26,6 +26,8 @@ import org.briarproject.bramble.api.rendezvous.event.RendezvousConnectionClosedE
 import org.briarproject.bramble.api.rendezvous.event.RendezvousConnectionOpenedEvent;
 import org.briarproject.bramble.api.rendezvous.event.RendezvousPollEvent;
 import org.briarproject.bramble.api.system.Clock;
+import org.briarproject.bramble.api.system.TaskScheduler;
+import org.briarproject.bramble.api.system.TaskScheduler.Cancellable;
 import org.briarproject.bramble.test.BrambleMockTestCase;
 import org.briarproject.bramble.test.CaptureArgumentAction;
 import org.briarproject.bramble.test.DbExpectations;
@@ -37,7 +39,6 @@ import org.junit.Test;
 
 import java.util.Random;
 import java.util.concurrent.Executor;
-import java.util.concurrent.ScheduledExecutorService;
 import java.util.concurrent.atomic.AtomicReference;
 
 import static java.util.Collections.emptyList;
@@ -60,8 +61,7 @@ import static org.briarproject.bramble.test.TestUtils.getTransportProperties;
 
 public class RendezvousPollerImplTest extends BrambleMockTestCase {
 
-	private final ScheduledExecutorService scheduler =
+	private final TaskScheduler scheduler = context.mock(TaskScheduler.class);
-			context.mock(ScheduledExecutorService.class);
 	private final DatabaseComponent db = context.mock(DatabaseComponent.class);
 	private final IdentityManager identityManager =
 			context.mock(IdentityManager.class);
@@ -80,6 +80,7 @@ public class RendezvousPollerImplTest extends BrambleMockTestCase {
 			context.mock(KeyMaterialSource.class);
 	private final RendezvousEndpoint rendezvousEndpoint =
 			context.mock(RendezvousEndpoint.class);
+	private final Cancellable cancellable = context.mock(Cancellable.class);
 
 	private final Executor ioExecutor = new ImmediateExecutor();
 	private final PendingContact pendingContact = getPendingContact();
@@ -108,7 +109,7 @@ public class RendezvousPollerImplTest extends BrambleMockTestCase {
 		long beforeExpiry = pendingContact.getTimestamp()
 				+ RENDEZVOUS_TIMEOUT_MS - 1000;
 		long afterExpiry = beforeExpiry + POLLING_INTERVAL_MS;
-		AtomicReference<Runnable> capturePollTask = new AtomicReference<>();
+		AtomicReference<Runnable> capturePollTask;
 
 		// Start the service
 		context.checking(new DbExpectations() {{
@@ -122,21 +123,17 @@ public class RendezvousPollerImplTest extends BrambleMockTestCase {
 			oneOf(eventBus).broadcast(with(new PredicateMatcher<>(
 					PendingContactStateChangedEvent.class, e ->
 					e.getPendingContactState() == OFFLINE)));
-			// Capture the poll task
-			oneOf(scheduler).scheduleAtFixedRate(with(any(Runnable.class)),
-					with(POLLING_INTERVAL_MS), with(POLLING_INTERVAL_MS),
-					with(MILLISECONDS));
-			will(new CaptureArgumentAction<>(capturePollTask, Runnable.class,
-					0));
 		}});
 
 		expectDeriveRendezvousKey();
+		capturePollTask = expectSchedulePolling();
 
 		rendezvousPoller.startService();
 		context.assertIsSatisfied();
 
-		// Run the poll task - pending contact expires
+		// Run the poll task - pending contact expires, polling is cancelled
 		expectPendingContactExpires(afterExpiry);
+		expectCancelPolling();
 
 		capturePollTask.get().run();
 	}
@@ -158,10 +155,6 @@ public class RendezvousPollerImplTest extends BrambleMockTestCase {
 			oneOf(eventBus).broadcast(with(new PredicateMatcher<>(
 					PendingContactStateChangedEvent.class, e ->
 					e.getPendingContactState() == FAILED)));
-			// Schedule the poll task
-			oneOf(scheduler).scheduleAtFixedRate(with(any(Runnable.class)),
-					with(POLLING_INTERVAL_MS), with(POLLING_INTERVAL_MS),
-					with(MILLISECONDS));
 		}});
 
 		rendezvousPoller.startService();
@@ -178,13 +171,14 @@ public class RendezvousPollerImplTest extends BrambleMockTestCase {
 		rendezvousPoller.startService();
 		context.assertIsSatisfied();
 
-		// Enable the transport - no endpoints should be created yet
+		// Activate the transport - no endpoints should be created yet
 		expectGetPlugin();
 
-		rendezvousPoller.eventOccurred(new TransportEnabledEvent(transportId));
+		rendezvousPoller.eventOccurred(new TransportActiveEvent(transportId));
 		context.assertIsSatisfied();
 
-		// Add the pending contact - endpoint should be created and polled
+		// Add the pending contact - endpoint should be created and polled,
+		// polling should be scheduled
 		expectAddPendingContact(beforeExpiry, WAITING_FOR_CONNECTION);
 		expectDeriveRendezvousKey();
 		expectCreateEndpoint();
@@ -201,19 +195,23 @@ public class RendezvousPollerImplTest extends BrambleMockTestCase {
 					any(ConnectionHandler.class)))));
 		}});
 
+		expectSchedulePolling();
+
 		rendezvousPoller.eventOccurred(
 				new PendingContactAddedEvent(pendingContact));
 		context.assertIsSatisfied();
 
-		// Remove the pending contact - endpoint should be closed
+		// Remove the pending contact - endpoint should be closed,
+		// polling should be cancelled
 		expectCloseEndpoint();
+		expectCancelPolling();
 
 		rendezvousPoller.eventOccurred(
 				new PendingContactRemovedEvent(pendingContact.getId()));
 		context.assertIsSatisfied();
 
-		// Disable the transport - endpoint is already closed
+		// Deactivate the transport - endpoint is already closed
-		rendezvousPoller.eventOccurred(new TransportDisabledEvent(transportId));
+		rendezvousPoller.eventOccurred(new TransportInactiveEvent(transportId));
 	}
 
 	@Test
@@ -222,21 +220,22 @@ public class RendezvousPollerImplTest extends BrambleMockTestCase {
 		long beforeExpiry = pendingContact.getTimestamp()
 				+ RENDEZVOUS_TIMEOUT_MS - 1000;
 		long afterExpiry = beforeExpiry + POLLING_INTERVAL_MS;
+		AtomicReference<Runnable> capturePollTask;
 
-		// Start the service, capturing the poll task
+		// Start the service
-		AtomicReference<Runnable> capturePollTask =
+		expectStartupWithNoPendingContacts();
-				expectStartupWithNoPendingContacts();
 
 		rendezvousPoller.startService();
 		context.assertIsSatisfied();
 
-		// Enable the transport - no endpoints should be created yet
+		// Activate the transport - no endpoints should be created yet
 		expectGetPlugin();
 
-		rendezvousPoller.eventOccurred(new TransportEnabledEvent(transportId));
+		rendezvousPoller.eventOccurred(new TransportActiveEvent(transportId));
 		context.assertIsSatisfied();
 
-		// Add the pending contact - endpoint should be created and polled
+		// Add the pending contact - endpoint should be created and polled,
+		// polling should be scheduled
 		expectAddPendingContact(beforeExpiry, WAITING_FOR_CONNECTION);
 		expectDeriveRendezvousKey();
 		expectCreateEndpoint();
@@ -253,13 +252,17 @@ public class RendezvousPollerImplTest extends BrambleMockTestCase {
 					any(ConnectionHandler.class)))));
 		}});
 
+		capturePollTask = expectSchedulePolling();
+
 		rendezvousPoller.eventOccurred(
 				new PendingContactAddedEvent(pendingContact));
 		context.assertIsSatisfied();
 
-		// Run the poll task - pending contact expires, endpoint is closed
+		// Run the poll task - pending contact expires, endpoint is closed,
+		// polling is cancelled
 		expectPendingContactExpires(afterExpiry);
 		expectCloseEndpoint();
+		expectCancelPolling();
 
 		capturePollTask.get().run();
 		context.assertIsSatisfied();
@@ -269,12 +272,12 @@ public class RendezvousPollerImplTest extends BrambleMockTestCase {
 				new PendingContactRemovedEvent(pendingContact.getId()));
 		context.assertIsSatisfied();
 
-		// Disable the transport - endpoint is already closed
+		// Deactivate the transport - endpoint is already closed
-		rendezvousPoller.eventOccurred(new TransportDisabledEvent(transportId));
+		rendezvousPoller.eventOccurred(new TransportInactiveEvent(transportId));
 	}
 
 	@Test
-	public void testCreatesAndClosesEndpointsWhenTransportIsEnabledAndDisabled()
+	public void testCreatesAndClosesEndpointsWhenTransportIsActivatedAndDeactivated()
 			throws Exception {
 		long beforeExpiry = pendingContact.getTimestamp();
 
@@ -287,27 +290,30 @@ public class RendezvousPollerImplTest extends BrambleMockTestCase {
 		// Add the pending contact - no endpoints should be created yet
 		expectAddPendingContact(beforeExpiry, OFFLINE);
 		expectDeriveRendezvousKey();
+		expectSchedulePolling();
 
 		rendezvousPoller.eventOccurred(
 				new PendingContactAddedEvent(pendingContact));
 		context.assertIsSatisfied();
 
-		// Enable the transport - endpoint should be created
+		// Activate the transport - endpoint should be created
 		expectGetPlugin();
 		expectCreateEndpoint();
 		expectStateChangedEvent(WAITING_FOR_CONNECTION);
 
-		rendezvousPoller.eventOccurred(new TransportEnabledEvent(transportId));
+		rendezvousPoller.eventOccurred(new TransportActiveEvent(transportId));
 		context.assertIsSatisfied();
 
-		// Disable the transport - endpoint should be closed
+		// Deactivate the transport - endpoint should be closed
 		expectCloseEndpoint();
 		expectStateChangedEvent(OFFLINE);
 
-		rendezvousPoller.eventOccurred(new TransportDisabledEvent(transportId));
+		rendezvousPoller.eventOccurred(new TransportInactiveEvent(transportId));
 		context.assertIsSatisfied();
 
 		// Remove the pending contact - endpoint is already closed
+		expectCancelPolling();
+
 		rendezvousPoller.eventOccurred(
 				new PendingContactRemovedEvent(pendingContact.getId()));
 	}
@@ -349,8 +355,9 @@ public class RendezvousPollerImplTest extends BrambleMockTestCase {
 		rendezvousPoller.startService();
 		context.assertIsSatisfied();
 
-		// Run the poll task - pending contact expires
+		// Run the poll task - pending contact expires, polling is cancelled
 		expectPendingContactExpires(afterExpiry);
+		expectCancelPolling();
 
 		capturePollTask.get().run();
 		context.assertIsSatisfied();
@@ -386,8 +393,9 @@ public class RendezvousPollerImplTest extends BrambleMockTestCase {
 				new RendezvousConnectionOpenedEvent(pendingContact.getId()));
 		context.assertIsSatisfied();
 
-		// Run the poll task - pending contact expires
+		// Run the poll task - pending contact expires, polling is cancelled
 		expectPendingContactExpires(afterExpiry);
+		expectCancelPolling();
 
 		capturePollTask.get().run();
 		context.assertIsSatisfied();
@@ -418,8 +426,9 @@ public class RendezvousPollerImplTest extends BrambleMockTestCase {
 				new RendezvousConnectionOpenedEvent(pendingContact.getId()));
 		context.assertIsSatisfied();
 
-		// Run the poll task - pending contact expires
+		// Run the poll task - pending contact expires, polling is cancelled
 		expectPendingContactExpires(afterExpiry);
+		expectCancelPolling();
 
 		capturePollTask.get().run();
 		context.assertIsSatisfied();
@@ -448,6 +457,8 @@ public class RendezvousPollerImplTest extends BrambleMockTestCase {
 		context.assertIsSatisfied();
 
 		// Pending contact is removed - no event should be broadcast
+		expectCancelPolling();
+
 		rendezvousPoller.eventOccurred(
 				new PendingContactRemovedEvent(pendingContact.getId()));
 		context.assertIsSatisfied();
@@ -457,25 +468,35 @@ public class RendezvousPollerImplTest extends BrambleMockTestCase {
 				pendingContact.getId(), false));
 	}
 
-	private AtomicReference<Runnable> expectStartupWithNoPendingContacts()
+	private AtomicReference<Runnable> expectSchedulePolling() {
-			throws Exception {
-		Transaction txn = new Transaction(null, true);
 		AtomicReference<Runnable> capturePollTask = new AtomicReference<>();
 
+		context.checking(new Expectations() {{
+			oneOf(scheduler).scheduleWithFixedDelay(with(any(Runnable.class)),
+					with(any(Executor.class)), with(POLLING_INTERVAL_MS),
+					with(POLLING_INTERVAL_MS), with(MILLISECONDS));
+			will(doAll(new CaptureArgumentAction<>(capturePollTask,
+					Runnable.class, 0), returnValue(cancellable)));
+		}});
+
+		return capturePollTask;
+	}
+
+	private void expectCancelPolling() {
+		context.checking(new Expectations() {{
+			oneOf(cancellable).cancel();
+		}});
+	}
+
+	private void expectStartupWithNoPendingContacts() throws Exception {
+		Transaction txn = new Transaction(null, true);
+
 		context.checking(new DbExpectations() {{
 			// Load the pending contacts
 			oneOf(db).transaction(with(true), withDbRunnable(txn));
 			oneOf(db).getPendingContacts(txn);
 			will(returnValue(emptyList()));
-			// Capture the poll task
-			oneOf(scheduler).scheduleAtFixedRate(with(any(Runnable.class)),
-					with(POLLING_INTERVAL_MS), with(POLLING_INTERVAL_MS),
-					with(MILLISECONDS));
-			will(new CaptureArgumentAction<>(capturePollTask, Runnable.class,
-					0));
 		}});
-
-		return capturePollTask;
 	}
 
 	private void expectAddPendingContact(long now,
@@ -531,7 +552,6 @@ public class RendezvousPollerImplTest extends BrambleMockTestCase {
 	private AtomicReference<Runnable> expectStartupWithPendingContact(long now)
 			throws Exception {
 		Transaction txn = new Transaction(null, true);
-		AtomicReference<Runnable> capturePollTask = new AtomicReference<>();
 
 		context.checking(new DbExpectations() {{
 			// Load the pending contacts
@@ -544,17 +564,10 @@ public class RendezvousPollerImplTest extends BrambleMockTestCase {
 			oneOf(eventBus).broadcast(with(new PredicateMatcher<>(
 					PendingContactStateChangedEvent.class, e ->
 					e.getPendingContactState() == OFFLINE)));
-			// Capture the poll task
-			oneOf(scheduler).scheduleAtFixedRate(with(any(Runnable.class)),
-					with(POLLING_INTERVAL_MS), with(POLLING_INTERVAL_MS),
-					with(MILLISECONDS));
-			will(new CaptureArgumentAction<>(capturePollTask, Runnable.class,
-					0));
 		}});
 
 		expectDeriveRendezvousKey();
-
+		return expectSchedulePolling();
-		return capturePollTask;
 	}
 
 	private void expectPendingContactExpires(long now) {

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

@@ -1,6 +1,6 @@
 package org.briarproject.bramble.sync;
 
-import org.briarproject.bramble.BrambleCoreEagerSingletons;
+import org.briarproject.bramble.BrambleCoreIntegrationTestEagerSingletons;
 import org.briarproject.bramble.api.contact.ContactId;
 import org.briarproject.bramble.api.crypto.SecretKey;
 import org.briarproject.bramble.api.crypto.TransportCrypto;
@@ -73,7 +73,8 @@ public class SyncIntegrationTest extends BrambleTestCase {
 
 		SyncIntegrationTestComponent component =
 				DaggerSyncIntegrationTestComponent.builder().build();
-		BrambleCoreEagerSingletons.Helper.injectEagerSingletons(component);
+		BrambleCoreIntegrationTestEagerSingletons.Helper
+				.injectEagerSingletons(component);
 		component.inject(this);
 
 		contactId = getContactId();

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

@@ -1,6 +1,6 @@
 package org.briarproject.bramble.sync;
 
-import org.briarproject.bramble.BrambleCoreEagerSingletons;
+import org.briarproject.bramble.BrambleCoreIntegrationTestEagerSingletons;
 import org.briarproject.bramble.BrambleCoreModule;
 import org.briarproject.bramble.test.BrambleCoreIntegrationTestModule;
 
@@ -13,7 +13,8 @@ import dagger.Component;
 		BrambleCoreIntegrationTestModule.class,
 		BrambleCoreModule.class
 })
-interface SyncIntegrationTestComponent extends BrambleCoreEagerSingletons {
+interface SyncIntegrationTestComponent extends
+		BrambleCoreIntegrationTestEagerSingletons {
 
 	void inject(SyncIntegrationTest testCase);
 }

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

@@ -3,6 +3,8 @@ package org.briarproject.bramble.test;
 import org.briarproject.bramble.api.FeatureFlags;
 import org.briarproject.bramble.battery.DefaultBatteryManagerModule;
 import org.briarproject.bramble.event.DefaultEventExecutorModule;
+import org.briarproject.bramble.system.DefaultTaskSchedulerModule;
+import org.briarproject.bramble.system.DefaultWakefulIoExecutorModule;
 
 import dagger.Module;
 import dagger.Provides;
@@ -10,6 +12,8 @@ import dagger.Provides;
 @Module(includes = {
 		DefaultBatteryManagerModule.class,
 		DefaultEventExecutorModule.class,
+		DefaultTaskSchedulerModule.class,
+		DefaultWakefulIoExecutorModule.class,
 		TestDatabaseConfigModule.class,
 		TestPluginConfigModule.class,
 		TestSecureRandomModule.class

bramble-core/src/test/java/org/briarproject/bramble/transport/TransportKeyManagerImplTest.java

@@ -8,6 +8,7 @@ import org.briarproject.bramble.api.db.DatabaseComponent;
 import org.briarproject.bramble.api.db.Transaction;
 import org.briarproject.bramble.api.plugin.TransportId;
 import org.briarproject.bramble.api.system.Clock;
+import org.briarproject.bramble.api.system.TaskScheduler;
 import org.briarproject.bramble.api.transport.IncomingKeys;
 import org.briarproject.bramble.api.transport.KeySetId;
 import org.briarproject.bramble.api.transport.OutgoingKeys;
@@ -29,7 +30,6 @@ import java.util.Collection;
 import java.util.List;
 import java.util.Random;
 import java.util.concurrent.Executor;
-import java.util.concurrent.ScheduledExecutorService;
 
 import static java.util.Arrays.asList;
 import static java.util.Collections.singletonList;
@@ -55,8 +55,7 @@ public class TransportKeyManagerImplTest extends BrambleMockTestCase {
 	private final TransportCrypto transportCrypto =
 			context.mock(TransportCrypto.class);
 	private final Executor dbExecutor = context.mock(Executor.class);
-	private final ScheduledExecutorService scheduler =
+	private final TaskScheduler scheduler = context.mock(TaskScheduler.class);
-			context.mock(ScheduledExecutorService.class);
 	private final Clock clock = context.mock(Clock.class);
 
 	private final TransportId transportId = getTransportId();
@@ -118,7 +117,8 @@ public class TransportKeyManagerImplTest extends BrambleMockTestCase {
 					new TransportKeySet(keySetId, contactId, null, updated)));
 			// Schedule a key update at the start of the next time period
 			oneOf(scheduler).schedule(with(any(Runnable.class)),
-					with(timePeriodLength - 1), with(MILLISECONDS));
+					with(dbExecutor), with(timePeriodLength - 1),
+					with(MILLISECONDS));
 		}});
 
 		transportKeyManager.start(txn);
@@ -421,9 +421,8 @@ public class TransportKeyManagerImplTest extends BrambleMockTestCase {
 			}
 			// Schedule a key update at the start of the next time period
 			oneOf(scheduler).schedule(with(any(Runnable.class)),
-					with(timePeriodLength), with(MILLISECONDS));
+					with(dbExecutor), with(timePeriodLength),
-			will(new RunAction());
+					with(MILLISECONDS));
-			oneOf(dbExecutor).execute(with(any(Runnable.class)));
 			will(new RunAction());
 			// Start a transaction for updating keys
 			oneOf(db).transaction(with(false), withDbRunnable(txn1));
@@ -446,7 +445,8 @@ public class TransportKeyManagerImplTest extends BrambleMockTestCase {
 					new TransportKeySet(keySetId, contactId, null, updated)));
 			// Schedule a key update at the start of the next time period
 			oneOf(scheduler).schedule(with(any(Runnable.class)),
-					with(timePeriodLength), with(MILLISECONDS));
+					with(dbExecutor), with(timePeriodLength),
+					with(MILLISECONDS));
 		}});
 
 		transportKeyManager.start(txn);