DO NOT MERGE: Add hacky poller method for testing discovery.

Discovery finishes quickly on some devices if called at the wrong time.

bramble-android/build.gradle

@@ -38,7 +38,7 @@ configurations {
 
 dependencies {
 	implementation project(path: ':bramble-core', configuration: 'default')
-	tor 'org.briarproject:tor-android:0.3.5.10@zip'
+	tor 'org.briarproject:tor-android:0.3.5.9@zip'
 	tor 'org.briarproject:obfs4proxy-android:0.0.11-2@zip'
 
 	annotationProcessor 'com.google.dagger:dagger-compiler:2.24'

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

@@ -8,24 +8,34 @@ import android.content.BroadcastReceiver;
 import android.content.Context;
 import android.content.Intent;
 import android.content.IntentFilter;
+import android.os.ParcelUuid;
+import android.os.Parcelable;
 
-import org.briarproject.bramble.api.io.TimeoutMonitor;
+import org.briarproject.bramble.api.Pair;
 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.DiscoveryHandler;
 import org.briarproject.bramble.api.plugin.PluginCallback;
 import org.briarproject.bramble.api.plugin.PluginException;
 import org.briarproject.bramble.api.plugin.duplex.DuplexTransportConnection;
+import org.briarproject.bramble.api.properties.TransportProperties;
 import org.briarproject.bramble.api.system.AndroidExecutor;
 import org.briarproject.bramble.api.system.Clock;
 import org.briarproject.bramble.util.AndroidUtils;
 import org.briarproject.bramble.util.IoUtils;
 
 import java.io.IOException;
+import java.lang.reflect.InvocationTargetException;
+import java.lang.reflect.Method;
+import java.nio.ByteBuffer;
 import java.security.SecureRandom;
 import java.util.ArrayList;
-import java.util.Collection;
+import java.util.HashMap;
 import java.util.List;
+import java.util.Map;
+import java.util.Set;
+import java.util.TreeSet;
 import java.util.UUID;
 import java.util.concurrent.BlockingQueue;
 import java.util.concurrent.ExecutionException;
@@ -47,15 +57,25 @@ import static android.bluetooth.BluetoothAdapter.SCAN_MODE_NONE;
 import static android.bluetooth.BluetoothAdapter.STATE_OFF;
 import static android.bluetooth.BluetoothAdapter.STATE_ON;
 import static android.bluetooth.BluetoothDevice.ACTION_FOUND;
+import static android.bluetooth.BluetoothDevice.ACTION_UUID;
 import static android.bluetooth.BluetoothDevice.DEVICE_TYPE_LE;
 import static android.bluetooth.BluetoothDevice.EXTRA_DEVICE;
+import static android.bluetooth.BluetoothDevice.EXTRA_UUID;
 import static android.os.Build.VERSION.SDK_INT;
+import static java.nio.ByteOrder.LITTLE_ENDIAN;
+import static java.util.Arrays.asList;
+import static java.util.Collections.emptyList;
 import static java.util.Collections.shuffle;
 import static java.util.concurrent.TimeUnit.MILLISECONDS;
 import static java.util.logging.Level.INFO;
 import static java.util.logging.Level.WARNING;
 import static java.util.logging.Logger.getLogger;
+import static org.briarproject.bramble.api.nullsafety.NullSafety.requireNonNull;
+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.util.LogUtils.logException;
 import static org.briarproject.bramble.util.PrivacyUtils.scrubMacAddress;
+import static org.briarproject.bramble.util.StringUtils.isNullOrEmpty;
 
 @MethodsNotNullByDefault
 @ParametersNotNullByDefault
@@ -64,7 +84,9 @@ class AndroidBluetoothPlugin extends BluetoothPlugin<BluetoothServerSocket> {
 	private static final Logger LOG =
 			getLogger(AndroidBluetoothPlugin.class.getName());
 
-	private static final int MAX_DISCOVERY_MS = 10_000;
+	private static final int MIN_DEVICE_DISCOVERY_MS = 2_000;
+	private static final int MAX_DEVICE_DISCOVERY_MS = 30_000;
+	private static final int MAX_SERVICE_DISCOVERY_MS = 15_000;
 
 	private final AndroidExecutor androidExecutor;
 	private final Context appContext;
@@ -77,12 +99,11 @@ class AndroidBluetoothPlugin extends BluetoothPlugin<BluetoothServerSocket> {
 	private volatile BluetoothAdapter adapter = null;
 
 	AndroidBluetoothPlugin(BluetoothConnectionLimiter connectionLimiter,
-			TimeoutMonitor timeoutMonitor, Executor ioExecutor,
-			SecureRandom secureRandom, AndroidExecutor androidExecutor,
-			Context appContext, Clock clock, Backoff backoff,
-			PluginCallback callback, int maxLatency, int maxIdleTime) {
-		super(connectionLimiter, timeoutMonitor, ioExecutor, secureRandom,
-				backoff, callback, maxLatency, maxIdleTime);
+			Executor ioExecutor, AndroidExecutor androidExecutor,
+			Context appContext, SecureRandom secureRandom, Clock clock,
+			Backoff backoff, PluginCallback callback, int maxLatency) {
+		super(connectionLimiter, ioExecutor, secureRandom, backoff, callback,
+				maxLatency);
 		this.androidExecutor = androidExecutor;
 		this.appContext = appContext;
 		this.clock = clock;
@@ -139,17 +160,42 @@ class AndroidBluetoothPlugin extends BluetoothPlugin<BluetoothServerSocket> {
 	@Override
 	void disableAdapterIfEnabledByUs() {
 		if (isAdapterEnabled() && wasEnabledByUs) {
+			cancelDiscoverability();
 			if (adapter.disable()) LOG.info("Disabling Bluetooth");
 			else LOG.info("Could not disable Bluetooth");
 			wasEnabledByUs = false;
 		}
 	}
 
+	private void cancelDiscoverability() {
+		if (adapter.getScanMode() == SCAN_MODE_CONNECTABLE_DISCOVERABLE) {
+			try {
+				Method setDiscoverableTimeout = BluetoothAdapter.class
+						.getDeclaredMethod("setDiscoverableTimeout", int.class);
+				setDiscoverableTimeout.setAccessible(true);
+				setDiscoverableTimeout.invoke(adapter, 1);
+				LOG.info("Cancelled discoverability");
+			} catch (NoSuchMethodException e) {
+				logException(LOG, WARNING, e);
+			} catch (IllegalAccessException e) {
+				logException(LOG, WARNING, e);
+			} catch (InvocationTargetException e) {
+				logException(LOG, WARNING, e);
+			}
+		}
+	}
+
 	@Override
 	void setEnabledByUs() {
 		wasEnabledByUs = true;
 	}
 
+	@Override
+	void onAdapterDisabled() {
+		super.onAdapterDisabled();
+		wasEnabledByUs = false;
+	}
+
 	@Override
 	@Nullable
 	String getBluetoothAddress() {
@@ -174,10 +220,9 @@ class AndroidBluetoothPlugin extends BluetoothPlugin<BluetoothServerSocket> {
 		return wrapSocket(ss.accept());
 	}
 
-	private DuplexTransportConnection wrapSocket(BluetoothSocket s)
-			throws IOException {
-		return new AndroidBluetoothTransportConnection(this, connectionLimiter,
-				timeoutMonitor, s);
+	private DuplexTransportConnection wrapSocket(BluetoothSocket s) {
+		return new AndroidBluetoothTransportConnection(this,
+				connectionLimiter, s);
 	}
 
 	@Override
@@ -205,7 +250,8 @@ class AndroidBluetoothPlugin extends BluetoothPlugin<BluetoothServerSocket> {
 	@Nullable
 	DuplexTransportConnection discoverAndConnect(String uuid) {
 		if (adapter == null) return null;
-		for (String address : discoverDevices()) {
+		for (BluetoothDevice d : discoverDevices()) {
+			String address = d.getAddress();
 			try {
 				if (LOG.isLoggable(INFO))
 					LOG.info("Connecting to " + scrubMacAddress(address));
@@ -221,10 +267,184 @@ class AndroidBluetoothPlugin extends BluetoothPlugin<BluetoothServerSocket> {
 		return null;
 	}
 
-	private Collection<String> discoverDevices() {
-		List<String> addresses = new ArrayList<>();
+	@Override
+	public boolean supportsDiscovery() {
+		return true;
+	}
+
+	@Override
+	public void discoverPeers(
+			List<Pair<TransportProperties, DiscoveryHandler>> properties) {
+		// Discover all nearby devices
+		List<BluetoothDevice> devices = discoverDevices();
+		if (devices.isEmpty()) {
+			LOG.info("No devices discovered");
+			return;
+		}
+
+		List<Pair<TransportProperties, DiscoveryHandler>> discovered =
+				new ArrayList<>();
+		Map<String, Pair<TransportProperties, DiscoveryHandler>> byUuid =
+				new HashMap<>();
+		Map<String, Pair<TransportProperties, DiscoveryHandler>> byAddress =
+				new HashMap<>();
+		for (Pair<TransportProperties, DiscoveryHandler> pair : properties) {
+			TransportProperties p = pair.getFirst();
+			String uuid = p.get(PROP_UUID);
+			if (!isNullOrEmpty(uuid)) {
+				byUuid.put(uuid, pair);
+				String address = p.get(PROP_ADDRESS);
+				if (!isNullOrEmpty(address)) byAddress.put(address, pair);
+			}
+		}
+
+		List<BluetoothDevice> unknown = new ArrayList<>(devices);
+		for (BluetoothDevice d : devices) {
+			Pair<TransportProperties, DiscoveryHandler> pair =
+					byAddress.remove(d.getAddress());
+			if (pair == null) {
+				// Try cached UUIDs
+				for (String uuid : getUuids(d)) {
+					pair = byUuid.remove(uuid);
+					if (pair != null) {
+						if (LOG.isLoggable(INFO)) {
+							LOG.info("Matched "
+									+ scrubMacAddress(d.getAddress())
+									+ " by cached UUID");
+						}
+						TransportProperties p =
+								new TransportProperties(pair.getFirst());
+						p.put(PROP_ADDRESS, d.getAddress());
+						discovered.add(new Pair<>(p, pair.getSecond()));
+						unknown.remove(d);
+						break;
+					}
+				}
+			} else {
+				if (LOG.isLoggable(INFO)) {
+					LOG.info("Matched " + scrubMacAddress(d.getAddress())
+							+ " by address");
+				}
+				discovered.add(pair);
+				unknown.remove(d);
+			}
+		}
+		if (unknown.isEmpty()) {
+			LOG.info("All discovered devices are known, not fetching UUIDs");
+			return;
+		}
+		// Fetch up-to-date UUIDs
+		if (LOG.isLoggable(INFO))
+			LOG.info("Fetching UUIDs for " + unknown.size() + " devices");
 		BlockingQueue<Intent> intents = new LinkedBlockingQueue<>();
-		DiscoveryReceiver receiver = new DiscoveryReceiver(intents);
+		QueueingReceiver receiver = new QueueingReceiver(intents);
+		IntentFilter filter = new IntentFilter();
+		filter.addAction(ACTION_UUID);
+		appContext.registerReceiver(receiver, filter);
+		try {
+			List<BluetoothDevice> pending = new ArrayList<>();
+			for (BluetoothDevice d : unknown) {
+				if (d.fetchUuidsWithSdp()) {
+					if (LOG.isLoggable(INFO)) {
+						LOG.info("Fetching UUIDs for "
+								+ scrubMacAddress(d.getAddress()));
+					}
+					pending.add(d);
+				} else {
+					if (LOG.isLoggable(INFO)) {
+						LOG.info("Failed to fetch UUIDs for "
+								+ scrubMacAddress(d.getAddress()));
+					}
+				}
+			}
+			long now = clock.currentTimeMillis();
+			long end = now + MAX_SERVICE_DISCOVERY_MS;
+			while (now < end && !pending.isEmpty()) {
+				Intent i = intents.poll(end - now, MILLISECONDS);
+				if (i == null) break;
+				BluetoothDevice d = requireNonNull(
+						i.getParcelableExtra(EXTRA_DEVICE));
+				if (LOG.isLoggable(INFO)) {
+					LOG.info("Fetched UUIDs for "
+							+ scrubMacAddress(d.getAddress()));
+				}
+				Set<String> uuids = getUuids(d);
+				Parcelable[] extra = i.getParcelableArrayExtra(EXTRA_UUID);
+				if (extra != null) {
+					for (Parcelable p : extra) {
+						uuids.addAll(getUuidStrings((ParcelUuid) p));
+					}
+				}
+				for (String uuid : uuids) {
+					Pair<TransportProperties, DiscoveryHandler> pair =
+							byUuid.remove(uuid);
+					if (pair != null) {
+						if (LOG.isLoggable(INFO)) {
+							LOG.info("Matched "
+									+ scrubMacAddress(d.getAddress())
+									+ " by fetched UUID");
+						}
+						TransportProperties p =
+								new TransportProperties(pair.getFirst());
+						p.put(PROP_ADDRESS, d.getAddress());
+						discovered.add(new Pair<>(p, pair.getSecond()));
+						break;
+					}
+				}
+				pending.remove(d);
+				now = clock.currentTimeMillis();
+			}
+			if (LOG.isLoggable(INFO)) {
+				if (pending.isEmpty()) {
+					LOG.info("Finished fetching UUIDs");
+				} else {
+					LOG.info("Failed to fetch UUIDs for " + pending.size()
+							+ " devices");
+				}
+			}
+		} catch (InterruptedException e) {
+			LOG.info("Interrupted while fetching UUIDs");
+			Thread.currentThread().interrupt();
+		} finally {
+			appContext.unregisterReceiver(receiver);
+		}
+
+		if (LOG.isLoggable(INFO)) {
+			LOG.info("Discovered " + discovered.size() + " contacts");
+		}
+		for (Pair<TransportProperties, DiscoveryHandler> pair : discovered) {
+			pair.getSecond().handleDevice(pair.getFirst());
+		}
+	}
+
+	private Set<String> getUuids(BluetoothDevice d) {
+		Set<String> strings = new TreeSet<>();
+		ParcelUuid[] uuids = d.getUuids();
+		if (uuids == null) return strings;
+		for (ParcelUuid u : uuids) strings.addAll(getUuidStrings(u));
+		return strings;
+	}
+
+	// Workaround for https://code.google.com/p/android/issues/detail?id=197341
+	private List<String> getUuidStrings(ParcelUuid u) {
+		UUID forwards = u.getUuid();
+		ByteBuffer buf = ByteBuffer.allocate(16);
+		buf.putLong(forwards.getLeastSignificantBits());
+		buf.putLong(forwards.getMostSignificantBits());
+		buf.rewind();
+		buf.order(LITTLE_ENDIAN);
+		UUID backwards = new UUID(buf.getLong(), buf.getLong());
+		return asList(forwards.toString(), backwards.toString());
+	}
+
+	private List<BluetoothDevice> discoverDevices() {
+		if (adapter.isDiscovering()) {
+			LOG.info("Already discovering");
+			return emptyList();
+		}
+		List<BluetoothDevice> devices = new ArrayList<>();
+		BlockingQueue<Intent> intents = new LinkedBlockingQueue<>();
+		QueueingReceiver receiver = new QueueingReceiver(intents);
 		IntentFilter filter = new IntentFilter();
 		filter.addAction(ACTION_DISCOVERY_STARTED);
 		filter.addAction(ACTION_DISCOVERY_FINISHED);
@@ -232,8 +452,9 @@ class AndroidBluetoothPlugin extends BluetoothPlugin<BluetoothServerSocket> {
 		appContext.registerReceiver(receiver, filter);
 		try {
 			if (adapter.startDiscovery()) {
-				long now = clock.currentTimeMillis();
-				long end = now + MAX_DISCOVERY_MS;
+				long start = clock.currentTimeMillis();
+				long end = start + MAX_DEVICE_DISCOVERY_MS;
+				long now = start;
 				while (now < end) {
 					Intent i = intents.poll(end - now, MILLISECONDS);
 					if (i == null) break;
@@ -242,17 +463,26 @@ class AndroidBluetoothPlugin extends BluetoothPlugin<BluetoothServerSocket> {
 						LOG.info("Discovery started");
 					} else if (ACTION_DISCOVERY_FINISHED.equals(action)) {
 						LOG.info("Discovery finished");
-						break;
+						now = clock.currentTimeMillis();
+						if (now - start < MIN_DEVICE_DISCOVERY_MS) {
+							LOG.info("Discovery finished quickly, retrying");
+							if (!adapter.startDiscovery()) {
+								LOG.info("Could not restart discovery");
+								break;
+							}
+						} else {
+							break;
+						}
 					} else if (ACTION_FOUND.equals(action)) {
-						BluetoothDevice d = i.getParcelableExtra(EXTRA_DEVICE);
+						BluetoothDevice d = requireNonNull(
+								i.getParcelableExtra(EXTRA_DEVICE));
 						// Ignore Bluetooth LE devices
 						if (SDK_INT < 18 || d.getType() != DEVICE_TYPE_LE) {
-							String address = d.getAddress();
-							if (LOG.isLoggable(INFO))
-								LOG.info("Discovered " +
-										scrubMacAddress(address));
-							if (!addresses.contains(address))
-								addresses.add(address);
+							if (LOG.isLoggable(INFO)) {
+								LOG.info("Discovered "
+										+ scrubMacAddress(d.getAddress()));
+							}
+							if (!devices.contains(d)) devices.add(d);
 						}
 					}
 					now = clock.currentTimeMillis();
@@ -268,9 +498,9 @@ class AndroidBluetoothPlugin extends BluetoothPlugin<BluetoothServerSocket> {
 			adapter.cancelDiscovery();
 			appContext.unregisterReceiver(receiver);
 		}
-		// Shuffle the addresses so we don't always try the same one first
-		shuffle(addresses);
-		return addresses;
+		// Shuffle the devices so we don't always try the same one first
+		shuffle(devices);
+		return devices;
 	}
 
 	private class BluetoothStateReceiver extends BroadcastReceiver {
@@ -291,11 +521,11 @@ class AndroidBluetoothPlugin extends BluetoothPlugin<BluetoothServerSocket> {
 		}
 	}
 
-	private static class DiscoveryReceiver extends BroadcastReceiver {
+	private static class QueueingReceiver extends BroadcastReceiver {
 
 		private final BlockingQueue<Intent> intents;
 
-		private DiscoveryReceiver(BlockingQueue<Intent> intents) {
+		private QueueingReceiver(BlockingQueue<Intent> intents) {
 			this.intents = intents;
 		}
 

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

@@ -3,7 +3,6 @@ package org.briarproject.bramble.plugin.bluetooth;
 import android.content.Context;
 
 import org.briarproject.bramble.api.event.EventBus;
-import org.briarproject.bramble.api.io.TimeoutMonitor;
 import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
 import org.briarproject.bramble.api.plugin.Backoff;
 import org.briarproject.bramble.api.plugin.BackoffFactory;
@@ -26,7 +25,6 @@ import static org.briarproject.bramble.api.plugin.BluetoothConstants.ID;
 public class AndroidBluetoothPluginFactory implements DuplexPluginFactory {
 
 	private static final int MAX_LATENCY = 30 * 1000; // 30 seconds
-	private static final int MAX_IDLE_TIME = 30 * 1000; // 30 seconds
 	private static final int MIN_POLLING_INTERVAL = 60 * 1000; // 1 minute
 	private static final int MAX_POLLING_INTERVAL = 10 * 60 * 1000; // 10 mins
 	private static final double BACKOFF_BASE = 1.2;
@@ -37,20 +35,18 @@ public class AndroidBluetoothPluginFactory implements DuplexPluginFactory {
 	private final SecureRandom secureRandom;
 	private final EventBus eventBus;
 	private final Clock clock;
-	private final TimeoutMonitor timeoutMonitor;
 	private final BackoffFactory backoffFactory;
 
 	public AndroidBluetoothPluginFactory(Executor ioExecutor,
 			AndroidExecutor androidExecutor, Context appContext,
 			SecureRandom secureRandom, EventBus eventBus, Clock clock,
-			TimeoutMonitor timeoutMonitor, BackoffFactory backoffFactory) {
+			BackoffFactory backoffFactory) {
 		this.ioExecutor = ioExecutor;
 		this.androidExecutor = androidExecutor;
 		this.appContext = appContext;
 		this.secureRandom = secureRandom;
 		this.eventBus = eventBus;
 		this.clock = clock;
-		this.timeoutMonitor = timeoutMonitor;
 		this.backoffFactory = backoffFactory;
 	}
 
@@ -71,9 +67,8 @@ public class AndroidBluetoothPluginFactory implements DuplexPluginFactory {
 		Backoff backoff = backoffFactory.createBackoff(MIN_POLLING_INTERVAL,
 				MAX_POLLING_INTERVAL, BACKOFF_BASE);
 		AndroidBluetoothPlugin plugin = new AndroidBluetoothPlugin(
-				connectionLimiter, timeoutMonitor, ioExecutor, secureRandom,
-				androidExecutor, appContext, clock, backoff,
-				callback, MAX_LATENCY, MAX_IDLE_TIME);
+				connectionLimiter, ioExecutor, androidExecutor, appContext,
+				secureRandom, clock, backoff, callback, MAX_LATENCY);
 		eventBus.addListener(plugin);
 		return plugin;
 	}

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

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

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

@@ -9,11 +9,11 @@ import android.net.wifi.WifiManager;
 
 import org.briarproject.bramble.PoliteExecutor;
 import org.briarproject.bramble.api.event.Event;
-import org.briarproject.bramble.api.event.EventListener;
 import org.briarproject.bramble.api.network.event.NetworkStatusEvent;
 import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
 import org.briarproject.bramble.api.plugin.Backoff;
 import org.briarproject.bramble.api.plugin.PluginCallback;
+import org.briarproject.bramble.api.settings.Settings;
 
 import java.io.IOException;
 import java.net.InetAddress;
@@ -32,10 +32,14 @@ import static android.net.ConnectivityManager.TYPE_WIFI;
 import static android.os.Build.VERSION.SDK_INT;
 import static java.util.Collections.emptyList;
 import static java.util.Collections.singletonList;
+import static java.util.logging.Level.WARNING;
 import static java.util.logging.Logger.getLogger;
+import static org.briarproject.bramble.api.plugin.Plugin.State.ACTIVE;
+import static org.briarproject.bramble.api.plugin.Plugin.State.INACTIVE;
+import static org.briarproject.bramble.util.IoUtils.tryToClose;
 
 @NotNullByDefault
-class AndroidLanTcpPlugin extends LanTcpPlugin implements EventListener {
+class AndroidLanTcpPlugin extends LanTcpPlugin {
 
 	private static final Logger LOG =
 			getLogger(AndroidLanTcpPlugin.class.getName());
@@ -68,16 +72,11 @@ 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, false));
 		updateConnectionStatus();
 	}
 
-	@Override
-	public void stop() {
-		running = false;
-		tryToClose(socket);
-	}
-
 	@Override
 	protected Socket createSocket() throws IOException {
 		return socketFactory.createSocket();
@@ -130,13 +129,15 @@ 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;
-			List<InetAddress> addrs = getUsableLocalInetAddresses();
+			State s = getState();
+			if (s != ACTIVE && s != INACTIVE) return;
+			List<InetAddress> addrs = getLocalInetAddresses();
 			if (addrs.contains(WIFI_AP_ADDRESS)
 					|| addrs.contains(WIFI_DIRECT_AP_ADDRESS)) {
 				LOG.info("Providing wifi hotspot");
@@ -145,15 +146,21 @@ class AndroidLanTcpPlugin extends LanTcpPlugin implements EventListener {
 				// make outgoing connections on API 21+ if another network
 				// has internet access
 				socketFactory = SocketFactory.getDefault();
-				if (socket == null || socket.isClosed()) bind();
+				if (s == INACTIVE) bind();
 			} else if (addrs.isEmpty()) {
 				LOG.info("Not connected to wifi");
 				socketFactory = SocketFactory.getDefault();
-				tryToClose(socket);
+				// Server socket may not have been closed automatically when
+				// interface was taken down. Socket will be cleared and state
+				// updated in acceptContactConnections()
+				if (s == ACTIVE) {
+					LOG.info("Closing server socket");
+					tryToClose(state.getServerSocket(), LOG, WARNING);
+				}
 			} else {
 				LOG.info("Connected to wifi");
 				socketFactory = getSocketFactory();
-				if (socket == null || socket.isClosed()) bind();
+				if (s == INACTIVE) bind();
 			}
 		});
 	}

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

@@ -74,7 +74,6 @@ 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();

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/util/AndroidUtils.java

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

bramble-android/witness.gradle

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

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

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

bramble-api/src/main/java/org/briarproject/bramble/api/connection/InterruptibleConnection.java

@@ -1,19 +0,0 @@
-package org.briarproject.bramble.api.connection;
-
-import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
-
-/**
- * A duplex sync connection that can be closed by interrupting its outgoing
- * sync session.
- */
-@NotNullByDefault
-public interface InterruptibleConnection {
-
-	/**
-	 * Interrupts the connection's outgoing sync session. If the underlying
-	 * transport connection is alive and the remote peer is cooperative, this
-	 * should result in both sync sessions ending and the connection being
-	 * cleanly closed.
-	 */
-	void interruptOutgoingSession();
-}

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

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

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

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

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

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

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

@@ -18,6 +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

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

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

@@ -8,6 +8,4 @@ public interface BluetoothConstants {
 
 	String PROP_ADDRESS = "address";
 	String PROP_UUID = "uuid";
-
-	String PREF_BT_ENABLE = "enable";
 }

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

@@ -1,11 +1,8 @@
-package org.briarproject.bramble.api.connection;
+package org.briarproject.bramble.api.plugin;
 
 import org.briarproject.bramble.api.contact.ContactId;
 import org.briarproject.bramble.api.contact.PendingContactId;
 import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
-import org.briarproject.bramble.api.plugin.TransportConnectionReader;
-import org.briarproject.bramble.api.plugin.TransportConnectionWriter;
-import org.briarproject.bramble.api.plugin.TransportId;
 import org.briarproject.bramble.api.plugin.duplex.DuplexTransportConnection;
 
 @NotNullByDefault

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

@@ -1,17 +1,14 @@
-package org.briarproject.bramble.api.connection;
+package org.briarproject.bramble.api.plugin;
 
 import org.briarproject.bramble.api.contact.ContactId;
 import org.briarproject.bramble.api.contact.PendingContactId;
 import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
-import org.briarproject.bramble.api.plugin.PluginConfig;
-import org.briarproject.bramble.api.plugin.TransportId;
 import org.briarproject.bramble.api.plugin.event.ConnectionClosedEvent;
 import org.briarproject.bramble.api.plugin.event.ConnectionOpenedEvent;
 import org.briarproject.bramble.api.plugin.event.ContactConnectedEvent;
 import org.briarproject.bramble.api.plugin.event.ContactDisconnectedEvent;
 import org.briarproject.bramble.api.rendezvous.event.RendezvousConnectionClosedEvent;
 import org.briarproject.bramble.api.rendezvous.event.RendezvousConnectionOpenedEvent;
-import org.briarproject.bramble.api.sync.Priority;
 
 import java.util.Collection;
 
@@ -23,57 +20,25 @@ public interface ConnectionRegistry {
 
 	/**
 	 * Registers a connection with the given contact over the given transport.
-	 * <p>
 	 * Broadcasts {@link ConnectionOpenedEvent}. Also broadcasts
 	 * {@link ContactConnectedEvent} if this is the only connection with the
 	 * contact.
 	 */
-	void registerConnection(ContactId c, TransportId t,
-			InterruptibleConnection conn, boolean incoming);
+	void registerConnection(ContactId c, TransportId t, boolean incoming);
 
 	/**
 	 * Unregisters a connection with the given contact over the given transport.
-	 * <p>
 	 * Broadcasts {@link ConnectionClosedEvent}. Also broadcasts
 	 * {@link ContactDisconnectedEvent} if this is the only connection with
 	 * the contact.
 	 */
-	void unregisterConnection(ContactId c, TransportId t,
-			InterruptibleConnection conn, boolean incoming, boolean exception);
-
-	/**
-	 * Sets the {@link Priority priority} of a connection that was previously
-	 * registered via {@link #registerConnection(ContactId, TransportId,
-	 * InterruptibleConnection, boolean)}.
-	 * <p>
-	 * If the registry has any "better" connections with the given contact, the
-	 * given connection will be interrupted. If the registry has any "worse"
-	 * connections with the given contact, those connections will be
-	 * interrupted.
-	 * <p>
-	 * Connection A is considered "better" than connection B if both
-	 * connections have had their priorities set, and either A's transport is
-	 * {@link PluginConfig#getTransportPreferences() preferred} to B's, or
-	 * they use the same transport and A has higher {@link Priority priority}
-	 * than B.
-	 * <p>
-	 * For backward compatibility, connections without priorities are not
-	 * considered better or worse than other connections.
-	 */
-	void setPriority(ContactId c, TransportId t, InterruptibleConnection conn,
-			Priority priority);
+	void unregisterConnection(ContactId c, TransportId t, boolean incoming);
 
 	/**
 	 * Returns any contacts that are connected via the given transport.
 	 */
 	Collection<ContactId> getConnectedContacts(TransportId t);
 
-	/**
-	 * Returns any contacts that are connected via the given transport or any
-	 * {@link PluginConfig#getTransportPreferences() better} transport.
-	 */
-	Collection<ContactId> getConnectedOrBetterContacts(TransportId t);
-
 	/**
 	 * Returns true if the given contact is connected via the given transport.
 	 */

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

@@ -0,0 +1,18 @@
+package org.briarproject.bramble.api.plugin;
+
+import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
+import org.briarproject.bramble.api.properties.TransportProperties;
+
+/**
+ * An interface for handling peers discovered by transport plugins.
+ */
+@NotNullByDefault
+public interface DiscoveryHandler {
+
+	/**
+	 * Handles a peer discovered by a transport plugin.
+	 *
+	 * @param p A set of properties describing the discovered peer.
+	 */
+	void handleDevice(TransportProperties p);
+}

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

@@ -3,12 +3,55 @@ package org.briarproject.bramble.api.plugin;
 import org.briarproject.bramble.api.Pair;
 import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
 import org.briarproject.bramble.api.properties.TransportProperties;
+import org.briarproject.bramble.api.settings.SettingsManager;
 
-import java.util.Collection;
+import java.util.List;
 
 @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.
 	 */
@@ -35,9 +78,18 @@ public interface Plugin {
 	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 +106,5 @@ public interface Plugin {
 	 * Attempts to create connections using the given transport properties,
 	 * passing any created connections to the corresponding handlers.
 	 */
-	void poll(Collection<Pair<TransportProperties, ConnectionHandler>>
-			properties);
+	void poll(List<Pair<TransportProperties, ConnectionHandler>> properties);
 }

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

@@ -1,6 +1,10 @@
 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;
 
@@ -32,12 +36,17 @@ 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();
-
-	/**
-	 * Signals that the transport is disabled.
-	 */
-	void transportDisabled();
+	void pluginStateChanged(State state);
 }

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

@@ -5,8 +5,6 @@ import org.briarproject.bramble.api.plugin.duplex.DuplexPluginFactory;
 import org.briarproject.bramble.api.plugin.simplex.SimplexPluginFactory;
 
 import java.util.Collection;
-import java.util.List;
-import java.util.Map;
 
 @NotNullByDefault
 public interface PluginConfig {
@@ -16,11 +14,4 @@ public interface PluginConfig {
 	Collection<SimplexPluginFactory> getSimplexFactories();
 
 	boolean shouldPoll();
-
-	/**
-	 * Returns a map representing transport preferences. For each entry in the
-	 * map, connections via the transports identified by the value are
-	 * preferred to connections via the transport identified by the key.
-	 */
-	Map<TransportId, List<TransportId>> getTransportPreferences();
 }

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

@@ -21,6 +21,21 @@ public interface TorConstants {
 	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;
 
+	/**
+	 * 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/duplex/AbstractDuplexTransportConnection.java

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

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

@@ -1,14 +1,18 @@
 package org.briarproject.bramble.api.plugin.duplex;
 
+import org.briarproject.bramble.api.Pair;
 import org.briarproject.bramble.api.data.BdfList;
 import org.briarproject.bramble.api.keyagreement.KeyAgreementListener;
 import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
 import org.briarproject.bramble.api.plugin.ConnectionHandler;
+import org.briarproject.bramble.api.plugin.DiscoveryHandler;
 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 java.util.List;
+
 import javax.annotation.Nullable;
 
 /**
@@ -58,4 +62,16 @@ public interface DuplexPlugin extends Plugin {
 	@Nullable
 	RendezvousEndpoint createRendezvousEndpoint(KeyMaterialSource k,
 			boolean alice, ConnectionHandler incoming);
+
+	/**
+	 * Returns true if the plugin supports peer discovery.
+	 */
+	boolean supportsDiscovery();
+
+	/**
+	 * Attempts to discover peers using the given transport properties, passing
+	 * any discovered peers to the corresponding handlers.
+	 */
+	void discoverPeers(List<Pair<TransportProperties, DiscoveryHandler>>
+			properties);
 }

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

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

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

@@ -13,14 +13,13 @@ public class ConnectionClosedEvent extends Event {
 
 	private final ContactId contactId;
 	private final TransportId transportId;
-	private final boolean incoming, exception;
+	private final boolean incoming;
 
 	public ConnectionClosedEvent(ContactId contactId, TransportId transportId,
-			boolean incoming, boolean exception) {
+			boolean incoming) {
 		this.contactId = contactId;
 		this.transportId = transportId;
 		this.incoming = incoming;
-		this.exception = exception;
 	}
 
 	public ContactId getContactId() {
@@ -34,8 +33,4 @@ public class ConnectionClosedEvent extends Event {
 	public boolean isIncoming() {
 		return incoming;
 	}
-
-	public boolean isException() {
-		return exception;
-	}
 }

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/properties/TransportPropertyConstants.java

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

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

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

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

@@ -1,23 +0,0 @@
-package org.briarproject.bramble.api.sync;
-
-import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
-
-import javax.annotation.concurrent.Immutable;
-
-/**
- * A record containing a nonce for choosing between redundant sessions.
- */
-@Immutable
-@NotNullByDefault
-public class Priority {
-
-	private final byte[] nonce;
-
-	public Priority(byte[] nonce) {
-		this.nonce = nonce;
-	}
-
-	public byte[] getNonce() {
-		return nonce;
-	}
-}

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

@@ -1,13 +0,0 @@
-package org.briarproject.bramble.api.sync;
-
-import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
-
-/**
- * An interface for handling a {@link Priority} record received by an
- * incoming {@link SyncSession}.
- */
-@NotNullByDefault
-public interface PriorityHandler {
-
-	void handle(Priority p);
-}

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

@@ -10,5 +10,4 @@ public interface RecordTypes {
 	byte OFFER = 2;
 	byte REQUEST = 3;
 	byte VERSIONS = 4;
-	byte PRIORITY = 5;
 }

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

@@ -49,10 +49,4 @@ public interface SyncConstants {
 	 * simultaneously.
 	 */
 	int MAX_SUPPORTED_VERSIONS = 10;
-
-	/**
-	 * The length of the priority nonce used for choosing between redundant
-	 * connections.
-	 */
-	int PRIORITY_NONCE_BYTES = 16;
 }

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

@@ -28,8 +28,4 @@ public interface SyncRecordReader {
 	boolean hasVersions() throws IOException;
 
 	Versions readVersions() throws IOException;
-
-	boolean hasPriority() throws IOException;
-
-	Priority readPriority() throws IOException;
 }

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

@@ -17,7 +17,5 @@ public interface SyncRecordWriter {
 
 	void writeVersions(Versions v) throws IOException;
 
-	void writePriority(Priority p) throws IOException;
-
 	void flush() throws IOException;
 }

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

@@ -6,18 +6,14 @@ import org.briarproject.bramble.api.transport.StreamWriter;
 
 import java.io.InputStream;
 
-import javax.annotation.Nullable;
-
 @NotNullByDefault
 public interface SyncSessionFactory {
 
-	SyncSession createIncomingSession(ContactId c, InputStream in,
-			PriorityHandler handler);
+	SyncSession createIncomingSession(ContactId c, InputStream in);
 
 	SyncSession createSimplexOutgoingSession(ContactId c, int maxLatency,
 			StreamWriter streamWriter);
 
 	SyncSession createDuplexOutgoingSession(ContactId c, int maxLatency,
-			int maxIdleTime, StreamWriter streamWriter,
-			@Nullable Priority priority);
+			int maxIdleTime, StreamWriter streamWriter);
 }

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

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

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

@@ -1,7 +1,6 @@
 package org.briarproject.bramble;
 
 import org.briarproject.bramble.client.ClientModule;
-import org.briarproject.bramble.connection.ConnectionModule;
 import org.briarproject.bramble.contact.ContactModule;
 import org.briarproject.bramble.crypto.CryptoExecutorModule;
 import org.briarproject.bramble.crypto.CryptoModule;
@@ -10,7 +9,6 @@ import org.briarproject.bramble.db.DatabaseExecutorModule;
 import org.briarproject.bramble.db.DatabaseModule;
 import org.briarproject.bramble.event.EventModule;
 import org.briarproject.bramble.identity.IdentityModule;
-import org.briarproject.bramble.io.IoModule;
 import org.briarproject.bramble.keyagreement.KeyAgreementModule;
 import org.briarproject.bramble.lifecycle.LifecycleModule;
 import org.briarproject.bramble.plugin.PluginModule;
@@ -29,7 +27,6 @@ import dagger.Module;
 
 @Module(includes = {
 		ClientModule.class,
-		ConnectionModule.class,
 		ContactModule.class,
 		CryptoModule.class,
 		CryptoExecutorModule.class,
@@ -38,7 +35,6 @@ import dagger.Module;
 		DatabaseExecutorModule.class,
 		EventModule.class,
 		IdentityModule.class,
-		IoModule.class,
 		KeyAgreementModule.class,
 		LifecycleModule.class,
 		PluginModule.class,

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

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

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

@@ -1,79 +0,0 @@
-package org.briarproject.bramble.connection;
-
-import org.briarproject.bramble.api.connection.ConnectionRegistry;
-import org.briarproject.bramble.api.db.DbException;
-import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
-import org.briarproject.bramble.api.plugin.TransportConnectionReader;
-import org.briarproject.bramble.api.plugin.TransportConnectionWriter;
-import org.briarproject.bramble.api.plugin.TransportId;
-import org.briarproject.bramble.api.transport.KeyManager;
-import org.briarproject.bramble.api.transport.StreamContext;
-import org.briarproject.bramble.api.transport.StreamReaderFactory;
-import org.briarproject.bramble.api.transport.StreamWriterFactory;
-
-import java.io.IOException;
-import java.io.InputStream;
-import java.util.logging.Logger;
-
-import javax.annotation.Nullable;
-
-import static java.util.logging.Level.WARNING;
-import static java.util.logging.Logger.getLogger;
-import static org.briarproject.bramble.api.transport.TransportConstants.TAG_LENGTH;
-import static org.briarproject.bramble.util.IoUtils.read;
-import static org.briarproject.bramble.util.LogUtils.logException;
-
-@NotNullByDefault
-abstract class Connection {
-
-	protected static final Logger LOG = getLogger(Connection.class.getName());
-
-	final KeyManager keyManager;
-	final ConnectionRegistry connectionRegistry;
-	final StreamReaderFactory streamReaderFactory;
-	final StreamWriterFactory streamWriterFactory;
-
-	Connection(KeyManager keyManager, ConnectionRegistry connectionRegistry,
-			StreamReaderFactory streamReaderFactory,
-			StreamWriterFactory streamWriterFactory) {
-		this.keyManager = keyManager;
-		this.connectionRegistry = connectionRegistry;
-		this.streamReaderFactory = streamReaderFactory;
-		this.streamWriterFactory = streamWriterFactory;
-	}
-
-	@Nullable
-	StreamContext recogniseTag(TransportConnectionReader reader,
-			TransportId transportId) {
-		StreamContext ctx;
-		try {
-			byte[] tag = readTag(reader.getInputStream());
-			return keyManager.getStreamContext(transportId, tag);
-		} catch (IOException | DbException e) {
-			logException(LOG, WARNING, e);
-			return null;
-		}
-	}
-
-	private byte[] readTag(InputStream in) throws IOException {
-		byte[] tag = new byte[TAG_LENGTH];
-		read(in, tag);
-		return tag;
-	}
-
-	void disposeOnError(TransportConnectionReader reader, boolean recognised) {
-		try {
-			reader.dispose(true, recognised);
-		} catch (IOException e) {
-			logException(LOG, WARNING, e);
-		}
-	}
-
-	void disposeOnError(TransportConnectionWriter writer) {
-		try {
-			writer.dispose(true);
-		} catch (IOException e) {
-			logException(LOG, WARNING, e);
-		}
-	}
-}

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

@@ -1,114 +0,0 @@
-package org.briarproject.bramble.connection;
-
-import org.briarproject.bramble.api.connection.ConnectionManager;
-import org.briarproject.bramble.api.connection.ConnectionRegistry;
-import org.briarproject.bramble.api.contact.ContactExchangeManager;
-import org.briarproject.bramble.api.contact.ContactId;
-import org.briarproject.bramble.api.contact.HandshakeManager;
-import org.briarproject.bramble.api.contact.PendingContactId;
-import org.briarproject.bramble.api.lifecycle.IoExecutor;
-import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
-import org.briarproject.bramble.api.plugin.TransportConnectionReader;
-import org.briarproject.bramble.api.plugin.TransportConnectionWriter;
-import org.briarproject.bramble.api.plugin.TransportId;
-import org.briarproject.bramble.api.plugin.duplex.DuplexTransportConnection;
-import org.briarproject.bramble.api.properties.TransportPropertyManager;
-import org.briarproject.bramble.api.sync.SyncSessionFactory;
-import org.briarproject.bramble.api.transport.KeyManager;
-import org.briarproject.bramble.api.transport.StreamReaderFactory;
-import org.briarproject.bramble.api.transport.StreamWriterFactory;
-
-import java.security.SecureRandom;
-import java.util.concurrent.Executor;
-
-import javax.annotation.concurrent.Immutable;
-import javax.inject.Inject;
-
-@Immutable
-@NotNullByDefault
-class ConnectionManagerImpl implements ConnectionManager {
-
-	private final Executor ioExecutor;
-	private final KeyManager keyManager;
-	private final StreamReaderFactory streamReaderFactory;
-	private final StreamWriterFactory streamWriterFactory;
-	private final SyncSessionFactory syncSessionFactory;
-	private final HandshakeManager handshakeManager;
-	private final ContactExchangeManager contactExchangeManager;
-	private final ConnectionRegistry connectionRegistry;
-	private final TransportPropertyManager transportPropertyManager;
-	private final SecureRandom secureRandom;
-
-	@Inject
-	ConnectionManagerImpl(@IoExecutor Executor ioExecutor,
-			KeyManager keyManager, StreamReaderFactory streamReaderFactory,
-			StreamWriterFactory streamWriterFactory,
-			SyncSessionFactory syncSessionFactory,
-			HandshakeManager handshakeManager,
-			ContactExchangeManager contactExchangeManager,
-			ConnectionRegistry connectionRegistry,
-			TransportPropertyManager transportPropertyManager,
-			SecureRandom secureRandom) {
-		this.ioExecutor = ioExecutor;
-		this.keyManager = keyManager;
-		this.streamReaderFactory = streamReaderFactory;
-		this.streamWriterFactory = streamWriterFactory;
-		this.syncSessionFactory = syncSessionFactory;
-		this.handshakeManager = handshakeManager;
-		this.contactExchangeManager = contactExchangeManager;
-		this.connectionRegistry = connectionRegistry;
-		this.transportPropertyManager = transportPropertyManager;
-		this.secureRandom = secureRandom;
-	}
-
-
-	@Override
-	public void manageIncomingConnection(TransportId t,
-			TransportConnectionReader r) {
-		ioExecutor.execute(new IncomingSimplexSyncConnection(keyManager,
-				connectionRegistry, streamReaderFactory, streamWriterFactory,
-				syncSessionFactory, transportPropertyManager, t, r));
-	}
-
-	@Override
-	public void manageIncomingConnection(TransportId t,
-			DuplexTransportConnection d) {
-		ioExecutor.execute(new IncomingDuplexSyncConnection(keyManager,
-				connectionRegistry, streamReaderFactory, streamWriterFactory,
-				syncSessionFactory, transportPropertyManager, ioExecutor,
-				t, d));
-	}
-
-	@Override
-	public void manageIncomingConnection(PendingContactId p, TransportId t,
-			DuplexTransportConnection d) {
-		ioExecutor.execute(new IncomingHandshakeConnection(keyManager,
-				connectionRegistry, streamReaderFactory, streamWriterFactory,
-				handshakeManager, contactExchangeManager, this, p, t, d));
-	}
-
-	@Override
-	public void manageOutgoingConnection(ContactId c, TransportId t,
-			TransportConnectionWriter w) {
-		ioExecutor.execute(new OutgoingSimplexSyncConnection(keyManager,
-				connectionRegistry, streamReaderFactory, streamWriterFactory,
-				syncSessionFactory, transportPropertyManager, c, t, w));
-	}
-
-	@Override
-	public void manageOutgoingConnection(ContactId c, TransportId t,
-			DuplexTransportConnection d) {
-		ioExecutor.execute(new OutgoingDuplexSyncConnection(keyManager,
-				connectionRegistry, streamReaderFactory, streamWriterFactory,
-				syncSessionFactory, transportPropertyManager, ioExecutor,
-				secureRandom, c, t, d));
-	}
-
-	@Override
-	public void manageOutgoingConnection(PendingContactId p, TransportId t,
-			DuplexTransportConnection d) {
-		ioExecutor.execute(new OutgoingHandshakeConnection(keyManager,
-				connectionRegistry, streamReaderFactory, streamWriterFactory,
-				handshakeManager, contactExchangeManager, this, p, t, d));
-	}
-}

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

@@ -1,26 +0,0 @@
-package org.briarproject.bramble.connection;
-
-import org.briarproject.bramble.api.connection.ConnectionManager;
-import org.briarproject.bramble.api.connection.ConnectionRegistry;
-
-import javax.inject.Singleton;
-
-import dagger.Module;
-import dagger.Provides;
-
-@Module
-public class ConnectionModule {
-
-	@Provides
-	ConnectionManager provideConnectionManager(
-			ConnectionManagerImpl connectionManager) {
-		return connectionManager;
-	}
-
-	@Provides
-	@Singleton
-	ConnectionRegistry provideConnectionRegistry(
-			ConnectionRegistryImpl connectionRegistry) {
-		return connectionRegistry;
-	}
-}

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

@@ -1,270 +0,0 @@
-package org.briarproject.bramble.connection;
-
-import org.briarproject.bramble.api.Bytes;
-import org.briarproject.bramble.api.connection.ConnectionRegistry;
-import org.briarproject.bramble.api.connection.InterruptibleConnection;
-import org.briarproject.bramble.api.contact.ContactId;
-import org.briarproject.bramble.api.contact.PendingContactId;
-import org.briarproject.bramble.api.event.EventBus;
-import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
-import org.briarproject.bramble.api.plugin.PluginConfig;
-import org.briarproject.bramble.api.plugin.TransportId;
-import org.briarproject.bramble.api.plugin.event.ConnectionClosedEvent;
-import org.briarproject.bramble.api.plugin.event.ConnectionOpenedEvent;
-import org.briarproject.bramble.api.plugin.event.ContactConnectedEvent;
-import org.briarproject.bramble.api.plugin.event.ContactDisconnectedEvent;
-import org.briarproject.bramble.api.rendezvous.event.RendezvousConnectionClosedEvent;
-import org.briarproject.bramble.api.rendezvous.event.RendezvousConnectionOpenedEvent;
-import org.briarproject.bramble.api.sync.Priority;
-
-import java.util.ArrayList;
-import java.util.Collection;
-import java.util.HashMap;
-import java.util.HashSet;
-import java.util.List;
-import java.util.Map;
-import java.util.Map.Entry;
-import java.util.Set;
-import java.util.logging.Logger;
-
-import javax.annotation.Nullable;
-import javax.annotation.concurrent.GuardedBy;
-import javax.annotation.concurrent.ThreadSafe;
-import javax.inject.Inject;
-
-import static java.util.Collections.emptyList;
-import static java.util.logging.Level.INFO;
-import static java.util.logging.Logger.getLogger;
-
-@ThreadSafe
-@NotNullByDefault
-class ConnectionRegistryImpl implements ConnectionRegistry {
-
-	private static final Logger LOG =
-			getLogger(ConnectionRegistryImpl.class.getName());
-
-	private final EventBus eventBus;
-	private final Map<TransportId, List<TransportId>> transportPrefs;
-
-	private final Object lock = new Object();
-	@GuardedBy("lock")
-	private final Map<ContactId, List<ConnectionRecord>> contactConnections;
-	@GuardedBy("lock")
-	private final Set<PendingContactId> connectedPendingContacts;
-
-	@Inject
-	ConnectionRegistryImpl(EventBus eventBus, PluginConfig pluginConfig) {
-		this.eventBus = eventBus;
-		transportPrefs = pluginConfig.getTransportPreferences();
-		contactConnections = new HashMap<>();
-		connectedPendingContacts = new HashSet<>();
-	}
-
-	@Override
-	public void registerConnection(ContactId c, TransportId t,
-			InterruptibleConnection conn, boolean incoming) {
-		if (LOG.isLoggable(INFO)) {
-			if (incoming) LOG.info("Incoming connection registered: " + t);
-			else LOG.info("Outgoing connection registered: " + t);
-		}
-		boolean firstConnection;
-		synchronized (lock) {
-			List<ConnectionRecord> recs = contactConnections.get(c);
-			if (recs == null) {
-				recs = new ArrayList<>();
-				contactConnections.put(c, recs);
-			}
-			firstConnection = recs.isEmpty();
-			recs.add(new ConnectionRecord(t, conn));
-		}
-		eventBus.broadcast(new ConnectionOpenedEvent(c, t, incoming));
-		if (firstConnection) {
-			LOG.info("Contact connected");
-			eventBus.broadcast(new ContactConnectedEvent(c));
-		}
-	}
-
-	@Override
-	public void setPriority(ContactId c, TransportId t,
-			InterruptibleConnection conn, Priority priority) {
-		if (LOG.isLoggable(INFO)) LOG.info("Setting connection priority: " + t);
-		List<InterruptibleConnection> toInterrupt;
-		boolean interruptNewConnection = false;
-		synchronized (lock) {
-			List<ConnectionRecord> recs = contactConnections.get(c);
-			if (recs == null) throw new IllegalArgumentException();
-			toInterrupt = new ArrayList<>(recs.size());
-			for (ConnectionRecord rec : recs) {
-				if (rec.conn == conn) {
-					// Store the priority of this connection
-					rec.priority = priority;
-				} else if (rec.priority != null) {
-					int compare = compareConnections(t, priority,
-							rec.transportId, rec.priority);
-					if (compare == -1) {
-						// The old connection is better than the new one
-						interruptNewConnection = true;
-					} else if (compare == 1 && !rec.interrupted) {
-						// The new connection is better than the old one
-						toInterrupt.add(rec.conn);
-						rec.interrupted = true;
-					}
-				}
-			}
-		}
-		if (interruptNewConnection) {
-			LOG.info("Interrupting new connection");
-			conn.interruptOutgoingSession();
-		}
-		for (InterruptibleConnection old : toInterrupt) {
-			LOG.info("Interrupting old connection");
-			old.interruptOutgoingSession();
-		}
-	}
-
-	private int compareConnections(TransportId tA, Priority pA, TransportId tB,
-			Priority pB) {
-		if (getBetterTransports(tA).contains(tB)) return -1;
-		if (getBetterTransports(tB).contains(tA)) return 1;
-		return tA.equals(tB) ? Bytes.compare(pA.getNonce(), pB.getNonce()) : 0;
-	}
-
-	private List<TransportId> getBetterTransports(TransportId t) {
-		List<TransportId> better = transportPrefs.get(t);
-		return better == null ? emptyList() : better;
-	}
-
-	@Override
-	public void unregisterConnection(ContactId c, TransportId t,
-			InterruptibleConnection conn, boolean incoming, boolean exception) {
-		if (LOG.isLoggable(INFO)) {
-			if (incoming) LOG.info("Incoming connection unregistered: " + t);
-			else LOG.info("Outgoing connection unregistered: " + t);
-		}
-		boolean lastConnection;
-		synchronized (lock) {
-			List<ConnectionRecord> recs = contactConnections.get(c);
-			if (recs == null || !recs.remove(new ConnectionRecord(t, conn)))
-				throw new IllegalArgumentException();
-			lastConnection = recs.isEmpty();
-		}
-		eventBus.broadcast(
-				new ConnectionClosedEvent(c, t, incoming, exception));
-		if (lastConnection) {
-			LOG.info("Contact disconnected");
-			eventBus.broadcast(new ContactDisconnectedEvent(c));
-		}
-	}
-
-	@Override
-	public Collection<ContactId> getConnectedContacts(TransportId t) {
-		synchronized (lock) {
-			List<ContactId> contactIds = new ArrayList<>();
-			for (Entry<ContactId, List<ConnectionRecord>> e :
-					contactConnections.entrySet()) {
-				for (ConnectionRecord rec : e.getValue()) {
-					if (rec.transportId.equals(t)) {
-						contactIds.add(e.getKey());
-						break;
-					}
-				}
-			}
-			if (LOG.isLoggable(INFO)) {
-				LOG.info(contactIds.size() + " contacts connected: " + t);
-			}
-			return contactIds;
-		}
-	}
-
-	@Override
-	public Collection<ContactId> getConnectedOrBetterContacts(TransportId t) {
-		synchronized (lock) {
-			List<TransportId> better = getBetterTransports(t);
-			List<ContactId> contactIds = new ArrayList<>();
-			for (Entry<ContactId, List<ConnectionRecord>> e :
-					contactConnections.entrySet()) {
-				for (ConnectionRecord rec : e.getValue()) {
-					if (rec.transportId.equals(t) ||
-							better.contains(rec.transportId)) {
-						contactIds.add(e.getKey());
-						break;
-					}
-				}
-			}
-			if (LOG.isLoggable(INFO)) {
-				LOG.info(contactIds.size()
-						+ " contacts connected or better: " + t);
-			}
-			return contactIds;
-		}
-	}
-
-	@Override
-	public boolean isConnected(ContactId c, TransportId t) {
-		synchronized (lock) {
-			List<ConnectionRecord> recs = contactConnections.get(c);
-			if (recs == null) return false;
-			for (ConnectionRecord rec : recs) {
-				if (rec.transportId.equals(t)) return true;
-			}
-			return false;
-		}
-	}
-
-	@Override
-	public boolean isConnected(ContactId c) {
-		synchronized (lock) {
-			return contactConnections.containsKey(c);
-		}
-	}
-
-	@Override
-	public boolean registerConnection(PendingContactId p) {
-		boolean added;
-		synchronized (lock) {
-			added = connectedPendingContacts.add(p);
-		}
-		if (added) eventBus.broadcast(new RendezvousConnectionOpenedEvent(p));
-		return added;
-	}
-
-	@Override
-	public void unregisterConnection(PendingContactId p, boolean success) {
-		synchronized (lock) {
-			if (!connectedPendingContacts.remove(p))
-				throw new IllegalArgumentException();
-		}
-		eventBus.broadcast(new RendezvousConnectionClosedEvent(p, success));
-	}
-
-	private static class ConnectionRecord {
-
-		private final TransportId transportId;
-		private final InterruptibleConnection conn;
-		@GuardedBy("lock")
-		@Nullable
-		private Priority priority = null;
-		@GuardedBy("lock")
-		private boolean interrupted = false;
-
-		private ConnectionRecord(TransportId transportId,
-				InterruptibleConnection conn) {
-			this.transportId = transportId;
-			this.conn = conn;
-		}
-
-		@Override
-		public boolean equals(Object o) {
-			if (o instanceof ConnectionRecord) {
-				return conn == ((ConnectionRecord) o).conn;
-			} else {
-				return false;
-			}
-		}
-
-		@Override
-		public int hashCode() {
-			return conn.hashCode();
-		}
-	}
-}

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

@@ -1,104 +0,0 @@
-package org.briarproject.bramble.connection;
-
-import org.briarproject.bramble.api.connection.ConnectionRegistry;
-import org.briarproject.bramble.api.connection.InterruptibleConnection;
-import org.briarproject.bramble.api.contact.ContactId;
-import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
-import org.briarproject.bramble.api.plugin.TransportConnectionReader;
-import org.briarproject.bramble.api.plugin.TransportConnectionWriter;
-import org.briarproject.bramble.api.plugin.TransportId;
-import org.briarproject.bramble.api.plugin.duplex.DuplexTransportConnection;
-import org.briarproject.bramble.api.properties.TransportProperties;
-import org.briarproject.bramble.api.properties.TransportPropertyManager;
-import org.briarproject.bramble.api.sync.Priority;
-import org.briarproject.bramble.api.sync.SyncSession;
-import org.briarproject.bramble.api.sync.SyncSessionFactory;
-import org.briarproject.bramble.api.transport.KeyManager;
-import org.briarproject.bramble.api.transport.StreamContext;
-import org.briarproject.bramble.api.transport.StreamReaderFactory;
-import org.briarproject.bramble.api.transport.StreamWriter;
-import org.briarproject.bramble.api.transport.StreamWriterFactory;
-
-import java.io.IOException;
-import java.util.concurrent.Executor;
-
-import javax.annotation.Nullable;
-import javax.annotation.concurrent.GuardedBy;
-
-import static org.briarproject.bramble.api.nullsafety.NullSafety.requireNonNull;
-
-@NotNullByDefault
-abstract class DuplexSyncConnection extends SyncConnection
-		implements InterruptibleConnection {
-
-	final Executor ioExecutor;
-	final TransportId transportId;
-	final TransportConnectionReader reader;
-	final TransportConnectionWriter writer;
-	final TransportProperties remote;
-
-	private final Object interruptLock = new Object();
-
-	@GuardedBy("interruptLock")
-	@Nullable
-	private SyncSession outgoingSession = null;
-	@GuardedBy("interruptLock")
-	private boolean interruptWaiting = false;
-
-	@Override
-	public void interruptOutgoingSession() {
-		synchronized (interruptLock) {
-			if (outgoingSession == null) interruptWaiting = true;
-			else outgoingSession.interrupt();
-		}
-	}
-
-	void setOutgoingSession(SyncSession outgoingSession) {
-		synchronized (interruptLock) {
-			this.outgoingSession = outgoingSession;
-			if (interruptWaiting) {
-				outgoingSession.interrupt();
-				interruptWaiting = false;
-			}
-		}
-	}
-
-	DuplexSyncConnection(KeyManager keyManager,
-			ConnectionRegistry connectionRegistry,
-			StreamReaderFactory streamReaderFactory,
-			StreamWriterFactory streamWriterFactory,
-			SyncSessionFactory syncSessionFactory,
-			TransportPropertyManager transportPropertyManager,
-			Executor ioExecutor, TransportId transportId,
-			DuplexTransportConnection connection) {
-		super(keyManager, connectionRegistry, streamReaderFactory,
-				streamWriterFactory, syncSessionFactory,
-				transportPropertyManager);
-		this.ioExecutor = ioExecutor;
-		this.transportId = transportId;
-		reader = connection.getReader();
-		writer = connection.getWriter();
-		remote = connection.getRemoteProperties();
-	}
-
-	void onReadError(boolean recognised) {
-		disposeOnError(reader, recognised);
-		disposeOnError(writer);
-		interruptOutgoingSession();
-	}
-
-	void onWriteError() {
-		disposeOnError(reader, true);
-		disposeOnError(writer);
-	}
-
-	SyncSession createDuplexOutgoingSession(StreamContext ctx,
-			TransportConnectionWriter w, @Nullable Priority priority)
-			throws IOException {
-		StreamWriter streamWriter = streamWriterFactory.createStreamWriter(
-				w.getOutputStream(), ctx);
-		ContactId c = requireNonNull(ctx.getContactId());
-		return syncSessionFactory.createDuplexOutgoingSession(c,
-				w.getMaxLatency(), w.getMaxIdleTime(), streamWriter, priority);
-	}
-}

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

@@ -1,72 +0,0 @@
-package org.briarproject.bramble.connection;
-
-import org.briarproject.bramble.api.connection.ConnectionManager;
-import org.briarproject.bramble.api.connection.ConnectionRegistry;
-import org.briarproject.bramble.api.contact.ContactExchangeManager;
-import org.briarproject.bramble.api.contact.HandshakeManager;
-import org.briarproject.bramble.api.contact.PendingContactId;
-import org.briarproject.bramble.api.db.DbException;
-import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
-import org.briarproject.bramble.api.plugin.TransportConnectionReader;
-import org.briarproject.bramble.api.plugin.TransportConnectionWriter;
-import org.briarproject.bramble.api.plugin.TransportId;
-import org.briarproject.bramble.api.plugin.duplex.DuplexTransportConnection;
-import org.briarproject.bramble.api.transport.KeyManager;
-import org.briarproject.bramble.api.transport.StreamContext;
-import org.briarproject.bramble.api.transport.StreamReaderFactory;
-import org.briarproject.bramble.api.transport.StreamWriterFactory;
-
-import javax.annotation.Nullable;
-
-import static java.util.logging.Level.WARNING;
-import static org.briarproject.bramble.util.LogUtils.logException;
-
-@NotNullByDefault
-abstract class HandshakeConnection extends Connection {
-
-	final HandshakeManager handshakeManager;
-	final ContactExchangeManager contactExchangeManager;
-	final ConnectionManager connectionManager;
-	final PendingContactId pendingContactId;
-	final TransportId transportId;
-	final DuplexTransportConnection connection;
-	final TransportConnectionReader reader;
-	final TransportConnectionWriter writer;
-
-	HandshakeConnection(KeyManager keyManager,
-			ConnectionRegistry connectionRegistry,
-			StreamReaderFactory streamReaderFactory,
-			StreamWriterFactory streamWriterFactory,
-			HandshakeManager handshakeManager,
-			ContactExchangeManager contactExchangeManager,
-			ConnectionManager connectionManager,
-			PendingContactId pendingContactId,
-			TransportId transportId, DuplexTransportConnection connection) {
-		super(keyManager, connectionRegistry, streamReaderFactory,
-				streamWriterFactory);
-		this.handshakeManager = handshakeManager;
-		this.contactExchangeManager = contactExchangeManager;
-		this.connectionManager = connectionManager;
-		this.pendingContactId = pendingContactId;
-		this.transportId = transportId;
-		this.connection = connection;
-		reader = connection.getReader();
-		writer = connection.getWriter();
-	}
-
-	@Nullable
-	StreamContext allocateStreamContext(PendingContactId pendingContactId,
-			TransportId transportId) {
-		try {
-			return keyManager.getStreamContext(pendingContactId, transportId);
-		} catch (DbException e) {
-			logException(LOG, WARNING, e);
-			return null;
-		}
-	}
-
-	void onError(boolean recognised) {
-		disposeOnError(reader, recognised);
-		disposeOnError(writer);
-	}
-}

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

@@ -1,107 +0,0 @@
-package org.briarproject.bramble.connection;
-
-import org.briarproject.bramble.api.connection.ConnectionRegistry;
-import org.briarproject.bramble.api.contact.ContactId;
-import org.briarproject.bramble.api.db.DbException;
-import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
-import org.briarproject.bramble.api.plugin.TransportId;
-import org.briarproject.bramble.api.plugin.duplex.DuplexTransportConnection;
-import org.briarproject.bramble.api.properties.TransportPropertyManager;
-import org.briarproject.bramble.api.sync.PriorityHandler;
-import org.briarproject.bramble.api.sync.SyncSession;
-import org.briarproject.bramble.api.sync.SyncSessionFactory;
-import org.briarproject.bramble.api.transport.KeyManager;
-import org.briarproject.bramble.api.transport.StreamContext;
-import org.briarproject.bramble.api.transport.StreamReaderFactory;
-import org.briarproject.bramble.api.transport.StreamWriterFactory;
-
-import java.io.IOException;
-import java.util.concurrent.Executor;
-
-import static java.util.logging.Level.WARNING;
-import static org.briarproject.bramble.util.LogUtils.logException;
-
-@NotNullByDefault
-class IncomingDuplexSyncConnection extends DuplexSyncConnection
-		implements Runnable {
-
-	IncomingDuplexSyncConnection(KeyManager keyManager,
-			ConnectionRegistry connectionRegistry,
-			StreamReaderFactory streamReaderFactory,
-			StreamWriterFactory streamWriterFactory,
-			SyncSessionFactory syncSessionFactory,
-			TransportPropertyManager transportPropertyManager,
-			Executor ioExecutor, TransportId transportId,
-			DuplexTransportConnection connection) {
-		super(keyManager, connectionRegistry, streamReaderFactory,
-				streamWriterFactory, syncSessionFactory,
-				transportPropertyManager, ioExecutor, transportId, connection);
-	}
-
-	@Override
-	public void run() {
-		// Read and recognise the tag
-		StreamContext ctx = recogniseTag(reader, transportId);
-		if (ctx == null) {
-			LOG.info("Unrecognised tag");
-			onReadError(false);
-			return;
-		}
-		ContactId contactId = ctx.getContactId();
-		if (contactId == null) {
-			LOG.warning("Expected contact tag, got rendezvous tag");
-			onReadError(true);
-			return;
-		}
-		if (ctx.isHandshakeMode()) {
-			// TODO: Support handshake mode for contacts
-			LOG.warning("Received handshake tag, expected rotation mode");
-			onReadError(true);
-			return;
-		}
-		connectionRegistry.registerConnection(contactId, transportId,
-				this, true);
-		// Start the outgoing session on another thread
-		ioExecutor.execute(() -> runOutgoingSession(contactId));
-		try {
-			// Store any transport properties discovered from the connection
-			transportPropertyManager.addRemotePropertiesFromConnection(
-					contactId, transportId, remote);
-			// Update the connection registry when we receive our priority
-			PriorityHandler handler = p -> connectionRegistry.setPriority(
-					contactId, transportId, this, p);
-			// Create and run the incoming session
-			createIncomingSession(ctx, reader, handler).run();
-			reader.dispose(false, true);
-			interruptOutgoingSession();
-			connectionRegistry.unregisterConnection(contactId, transportId,
-					this, true, false);
-		} catch (DbException | IOException e) {
-			logException(LOG, WARNING, e);
-			onReadError(true);
-			connectionRegistry.unregisterConnection(contactId, transportId,
-					this, true, true);
-		}
-	}
-
-	private void runOutgoingSession(ContactId contactId) {
-		// Allocate a stream context
-		StreamContext ctx = allocateStreamContext(contactId, transportId);
-		if (ctx == null) {
-			LOG.warning("Could not allocate stream context");
-			onWriteError();
-			return;
-		}
-		try {
-			// Create and run the outgoing session
-			SyncSession out = createDuplexOutgoingSession(ctx, writer, null);
-			setOutgoingSession(out);
-			out.run();
-			writer.dispose(false);
-		} catch (IOException e) {
-			logException(LOG, WARNING, e);
-			onWriteError();
-		}
-	}
-}
-

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

@@ -1,93 +0,0 @@
-package org.briarproject.bramble.connection;
-
-import org.briarproject.bramble.api.connection.ConnectionManager;
-import org.briarproject.bramble.api.connection.ConnectionRegistry;
-import org.briarproject.bramble.api.contact.ContactExchangeManager;
-import org.briarproject.bramble.api.contact.HandshakeManager;
-import org.briarproject.bramble.api.contact.HandshakeManager.HandshakeResult;
-import org.briarproject.bramble.api.contact.PendingContactId;
-import org.briarproject.bramble.api.db.DbException;
-import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
-import org.briarproject.bramble.api.plugin.TransportId;
-import org.briarproject.bramble.api.plugin.duplex.DuplexTransportConnection;
-import org.briarproject.bramble.api.transport.KeyManager;
-import org.briarproject.bramble.api.transport.StreamContext;
-import org.briarproject.bramble.api.transport.StreamReaderFactory;
-import org.briarproject.bramble.api.transport.StreamWriter;
-import org.briarproject.bramble.api.transport.StreamWriterFactory;
-
-import java.io.IOException;
-import java.io.InputStream;
-
-import static java.util.logging.Level.WARNING;
-import static org.briarproject.bramble.util.LogUtils.logException;
-
-@NotNullByDefault
-class IncomingHandshakeConnection extends HandshakeConnection
-		implements Runnable {
-
-	IncomingHandshakeConnection(KeyManager keyManager,
-			ConnectionRegistry connectionRegistry,
-			StreamReaderFactory streamReaderFactory,
-			StreamWriterFactory streamWriterFactory,
-			HandshakeManager handshakeManager,
-			ContactExchangeManager contactExchangeManager,
-			ConnectionManager connectionManager,
-			PendingContactId pendingContactId,
-			TransportId transportId, DuplexTransportConnection connection) {
-		super(keyManager, connectionRegistry, streamReaderFactory,
-				streamWriterFactory, handshakeManager, contactExchangeManager,
-				connectionManager, pendingContactId, transportId, connection);
-	}
-
-	@Override
-	public void run() {
-		// Read and recognise the tag
-		StreamContext ctxIn = recogniseTag(reader, transportId);
-		if (ctxIn == null) {
-			LOG.info("Unrecognised tag");
-			onError(false);
-			return;
-		}
-		PendingContactId inPendingContactId = ctxIn.getPendingContactId();
-		if (inPendingContactId == null) {
-			LOG.warning("Expected rendezvous tag, got contact tag");
-			onError(true);
-			return;
-		}
-		// Allocate the outgoing stream context
-		StreamContext ctxOut =
-				allocateStreamContext(pendingContactId, transportId);
-		if (ctxOut == null) {
-			LOG.warning("Could not allocate stream context");
-			onError(true);
-			return;
-		}
-		// Close the connection if it's redundant
-		if (!connectionRegistry.registerConnection(pendingContactId)) {
-			LOG.info("Redundant rendezvous connection");
-			onError(true);
-			return;
-		}
-		// Handshake and exchange contacts
-		try {
-			InputStream in = streamReaderFactory.createStreamReader(
-					reader.getInputStream(), ctxIn);
-			// Flush the output stream to send the outgoing stream header
-			StreamWriter out = streamWriterFactory.createStreamWriter(
-					writer.getOutputStream(), ctxOut);
-			out.getOutputStream().flush();
-			HandshakeResult result =
-					handshakeManager.handshake(pendingContactId, in, out);
-			contactExchangeManager.exchangeContacts(pendingContactId,
-					connection, result.getMasterKey(), result.isAlice(), false);
-			connectionRegistry.unregisterConnection(pendingContactId, true);
-			// Reuse the connection as a transport connection
-			connectionManager.manageIncomingConnection(transportId, connection);
-		} catch (IOException | DbException e) {
-			logException(LOG, WARNING, e);
-			onError(true);
-			connectionRegistry.unregisterConnection(pendingContactId, false);
-		}
-	}
-}

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

@@ -1,79 +0,0 @@
-package org.briarproject.bramble.connection;
-
-import org.briarproject.bramble.api.connection.ConnectionRegistry;
-import org.briarproject.bramble.api.contact.ContactId;
-import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
-import org.briarproject.bramble.api.plugin.TransportConnectionReader;
-import org.briarproject.bramble.api.plugin.TransportId;
-import org.briarproject.bramble.api.properties.TransportPropertyManager;
-import org.briarproject.bramble.api.sync.PriorityHandler;
-import org.briarproject.bramble.api.sync.SyncSessionFactory;
-import org.briarproject.bramble.api.transport.KeyManager;
-import org.briarproject.bramble.api.transport.StreamContext;
-import org.briarproject.bramble.api.transport.StreamReaderFactory;
-import org.briarproject.bramble.api.transport.StreamWriterFactory;
-
-import java.io.IOException;
-
-import static java.util.logging.Level.WARNING;
-import static org.briarproject.bramble.util.LogUtils.logException;
-
-@NotNullByDefault
-class IncomingSimplexSyncConnection extends SyncConnection implements Runnable {
-
-	private final TransportId transportId;
-	private final TransportConnectionReader reader;
-
-	IncomingSimplexSyncConnection(KeyManager keyManager,
-			ConnectionRegistry connectionRegistry,
-			StreamReaderFactory streamReaderFactory,
-			StreamWriterFactory streamWriterFactory,
-			SyncSessionFactory syncSessionFactory,
-			TransportPropertyManager transportPropertyManager,
-			TransportId transportId, TransportConnectionReader reader) {
-		super(keyManager, connectionRegistry, streamReaderFactory,
-				streamWriterFactory, syncSessionFactory,
-				transportPropertyManager);
-		this.transportId = transportId;
-		this.reader = reader;
-	}
-
-	@Override
-	public void run() {
-		// Read and recognise the tag
-		StreamContext ctx = recogniseTag(reader, transportId);
-		if (ctx == null) {
-			LOG.info("Unrecognised tag");
-			onError(false);
-			return;
-		}
-		ContactId contactId = ctx.getContactId();
-		if (contactId == null) {
-			LOG.warning("Received rendezvous stream, expected contact");
-			onError(true);
-			return;
-		}
-		if (ctx.isHandshakeMode()) {
-			// TODO: Support handshake mode for contacts
-			LOG.warning("Received handshake tag, expected rotation mode");
-			onError(true);
-			return;
-		}
-		try {
-			// We don't expect to receive a priority for this connection
-			PriorityHandler handler = p ->
-					LOG.info("Ignoring priority for simplex connection");
-			// Create and run the incoming session
-			createIncomingSession(ctx, reader, handler).run();
-			reader.dispose(false, true);
-		} catch (IOException e) {
-			logException(LOG, WARNING, e);
-			onError(true);
-		}
-	}
-
-	private void onError(boolean recognised) {
-		disposeOnError(reader, recognised);
-	}
-}
-

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

@@ -1,141 +0,0 @@
-package org.briarproject.bramble.connection;
-
-import org.briarproject.bramble.api.connection.ConnectionRegistry;
-import org.briarproject.bramble.api.contact.ContactId;
-import org.briarproject.bramble.api.db.DbException;
-import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
-import org.briarproject.bramble.api.plugin.TransportId;
-import org.briarproject.bramble.api.plugin.duplex.DuplexTransportConnection;
-import org.briarproject.bramble.api.properties.TransportPropertyManager;
-import org.briarproject.bramble.api.sync.Priority;
-import org.briarproject.bramble.api.sync.PriorityHandler;
-import org.briarproject.bramble.api.sync.SyncSession;
-import org.briarproject.bramble.api.sync.SyncSessionFactory;
-import org.briarproject.bramble.api.transport.KeyManager;
-import org.briarproject.bramble.api.transport.StreamContext;
-import org.briarproject.bramble.api.transport.StreamReaderFactory;
-import org.briarproject.bramble.api.transport.StreamWriterFactory;
-
-import java.io.IOException;
-import java.security.SecureRandom;
-import java.util.concurrent.Executor;
-
-import static java.util.logging.Level.WARNING;
-import static org.briarproject.bramble.api.sync.SyncConstants.PRIORITY_NONCE_BYTES;
-import static org.briarproject.bramble.util.LogUtils.logException;
-
-@NotNullByDefault
-class OutgoingDuplexSyncConnection extends DuplexSyncConnection
-		implements Runnable {
-
-	private final SecureRandom secureRandom;
-	private final ContactId contactId;
-
-	OutgoingDuplexSyncConnection(KeyManager keyManager,
-			ConnectionRegistry connectionRegistry,
-			StreamReaderFactory streamReaderFactory,
-			StreamWriterFactory streamWriterFactory,
-			SyncSessionFactory syncSessionFactory,
-			TransportPropertyManager transportPropertyManager,
-			Executor ioExecutor, SecureRandom secureRandom, ContactId contactId,
-			TransportId transportId, DuplexTransportConnection connection) {
-		super(keyManager, connectionRegistry, streamReaderFactory,
-				streamWriterFactory, syncSessionFactory,
-				transportPropertyManager, ioExecutor, transportId, connection);
-		this.secureRandom = secureRandom;
-		this.contactId = contactId;
-	}
-
-	@Override
-	public void run() {
-		// Allocate a stream context
-		StreamContext ctx = allocateStreamContext(contactId, transportId);
-		if (ctx == null) {
-			LOG.warning("Could not allocate stream context");
-			onWriteError();
-			return;
-		}
-		if (ctx.isHandshakeMode()) {
-			// TODO: Support handshake mode for contacts
-			LOG.warning("Cannot use handshake mode stream context");
-			onWriteError();
-			return;
-		}
-		// Start the incoming session on another thread
-		Priority priority = generatePriority();
-		ioExecutor.execute(() -> runIncomingSession(priority));
-		try {
-			// Create and run the outgoing session
-			SyncSession out =
-					createDuplexOutgoingSession(ctx, writer, priority);
-			setOutgoingSession(out);
-			out.run();
-			writer.dispose(false);
-		} catch (IOException e) {
-			logException(LOG, WARNING, e);
-			onWriteError();
-		}
-	}
-
-	private void runIncomingSession(Priority priority) {
-		// Read and recognise the tag
-		StreamContext ctx = recogniseTag(reader, transportId);
-		// Unrecognised tags are suspicious in this case
-		if (ctx == null) {
-			LOG.warning("Unrecognised tag for returning stream");
-			onReadError();
-			return;
-		}
-		// Check that the stream comes from the expected contact
-		ContactId inContactId = ctx.getContactId();
-		if (inContactId == null) {
-			LOG.warning("Expected contact tag, got rendezvous tag");
-			onReadError();
-			return;
-		}
-		if (!contactId.equals(inContactId)) {
-			LOG.warning("Wrong contact ID for returning stream");
-			onReadError();
-			return;
-		}
-		if (ctx.isHandshakeMode()) {
-			// TODO: Support handshake mode for contacts
-			LOG.warning("Received handshake tag, expected rotation mode");
-			onReadError();
-			return;
-		}
-		connectionRegistry.registerConnection(contactId, transportId,
-				this, false);
-		connectionRegistry.setPriority(contactId, transportId, this, priority);
-		try {
-			// Store any transport properties discovered from the connection
-			transportPropertyManager.addRemotePropertiesFromConnection(
-					contactId, transportId, remote);
-			// We don't expect to receive a priority for this connection
-			PriorityHandler handler = p ->
-					LOG.info("Ignoring priority for outgoing connection");
-			// Create and run the incoming session
-			createIncomingSession(ctx, reader, handler).run();
-			reader.dispose(false, true);
-			interruptOutgoingSession();
-			connectionRegistry.unregisterConnection(contactId, transportId,
-					this, false, false);
-		} catch (DbException | IOException e) {
-			logException(LOG, WARNING, e);
-			onReadError();
-			connectionRegistry.unregisterConnection(contactId, transportId,
-					this, false, true);
-		}
-	}
-
-	private void onReadError() {
-		// 'Recognised' is always true for outgoing connections
-		onReadError(true);
-	}
-
-	private Priority generatePriority() {
-		byte[] nonce = new byte[PRIORITY_NONCE_BYTES];
-		secureRandom.nextBytes(nonce);
-		return new Priority(nonce);
-	}
-}

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

@@ -1,115 +0,0 @@
-package org.briarproject.bramble.connection;
-
-import org.briarproject.bramble.api.connection.ConnectionManager;
-import org.briarproject.bramble.api.connection.ConnectionRegistry;
-import org.briarproject.bramble.api.contact.Contact;
-import org.briarproject.bramble.api.contact.ContactExchangeManager;
-import org.briarproject.bramble.api.contact.HandshakeManager;
-import org.briarproject.bramble.api.contact.HandshakeManager.HandshakeResult;
-import org.briarproject.bramble.api.contact.PendingContactId;
-import org.briarproject.bramble.api.db.DbException;
-import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
-import org.briarproject.bramble.api.plugin.TransportId;
-import org.briarproject.bramble.api.plugin.duplex.DuplexTransportConnection;
-import org.briarproject.bramble.api.transport.KeyManager;
-import org.briarproject.bramble.api.transport.StreamContext;
-import org.briarproject.bramble.api.transport.StreamReaderFactory;
-import org.briarproject.bramble.api.transport.StreamWriter;
-import org.briarproject.bramble.api.transport.StreamWriterFactory;
-
-import java.io.IOException;
-import java.io.InputStream;
-
-import static java.util.logging.Level.WARNING;
-import static org.briarproject.bramble.util.LogUtils.logException;
-
-@NotNullByDefault
-class OutgoingHandshakeConnection extends HandshakeConnection
-		implements Runnable {
-
-	OutgoingHandshakeConnection(KeyManager keyManager,
-			ConnectionRegistry connectionRegistry,
-			StreamReaderFactory streamReaderFactory,
-			StreamWriterFactory streamWriterFactory,
-			HandshakeManager handshakeManager,
-			ContactExchangeManager contactExchangeManager,
-			ConnectionManager connectionManager,
-			PendingContactId pendingContactId,
-			TransportId transportId, DuplexTransportConnection connection) {
-		super(keyManager, connectionRegistry, streamReaderFactory,
-				streamWriterFactory, handshakeManager, contactExchangeManager,
-				connectionManager, pendingContactId, transportId, connection);
-	}
-
-	@Override
-	public void run() {
-		// Allocate the outgoing stream context
-		StreamContext ctxOut =
-				allocateStreamContext(pendingContactId, transportId);
-		if (ctxOut == null) {
-			LOG.warning("Could not allocate stream context");
-			onError();
-			return;
-		}
-		// Flush the output stream to send the outgoing stream header
-		StreamWriter out;
-		try {
-			out = streamWriterFactory.createStreamWriter(
-					writer.getOutputStream(), ctxOut);
-			out.getOutputStream().flush();
-		} catch (IOException e) {
-			logException(LOG, WARNING, e);
-			onError();
-			return;
-		}
-		// Read and recognise the tag
-		StreamContext ctxIn = recogniseTag(reader, transportId);
-		// Unrecognised tags are suspicious in this case
-		if (ctxIn == null) {
-			LOG.warning("Unrecognised tag for returning stream");
-			onError();
-			return;
-		}
-		// Check that the stream comes from the expected pending contact
-		PendingContactId inPendingContactId = ctxIn.getPendingContactId();
-		if (inPendingContactId == null) {
-			LOG.warning("Expected rendezvous tag, got contact tag");
-			onError();
-			return;
-		}
-		if (!inPendingContactId.equals(pendingContactId)) {
-			LOG.warning("Wrong pending contact ID for returning stream");
-			onError();
-			return;
-		}
-		// Close the connection if it's redundant
-		if (!connectionRegistry.registerConnection(pendingContactId)) {
-			LOG.info("Redundant rendezvous connection");
-			onError();
-			return;
-		}
-		// Handshake and exchange contacts
-		try {
-			InputStream in = streamReaderFactory.createStreamReader(
-					reader.getInputStream(), ctxIn);
-			HandshakeResult result =
-					handshakeManager.handshake(pendingContactId, in, out);
-			Contact contact = contactExchangeManager.exchangeContacts(
-					pendingContactId, connection, result.getMasterKey(),
-					result.isAlice(), false);
-			connectionRegistry.unregisterConnection(pendingContactId, true);
-			// Reuse the connection as a transport connection
-			connectionManager.manageOutgoingConnection(contact.getId(),
-					transportId, connection);
-		} catch (IOException | DbException e) {
-			logException(LOG, WARNING, e);
-			onError();
-			connectionRegistry.unregisterConnection(pendingContactId, false);
-		}
-	}
-
-	private void onError() {
-		// 'Recognised' is always true for outgoing connections
-		onError(true);
-	}
-}

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

@@ -1,78 +0,0 @@
-package org.briarproject.bramble.connection;
-
-import org.briarproject.bramble.api.connection.ConnectionRegistry;
-import org.briarproject.bramble.api.contact.ContactId;
-import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
-import org.briarproject.bramble.api.plugin.TransportConnectionWriter;
-import org.briarproject.bramble.api.plugin.TransportId;
-import org.briarproject.bramble.api.properties.TransportPropertyManager;
-import org.briarproject.bramble.api.sync.SyncSession;
-import org.briarproject.bramble.api.sync.SyncSessionFactory;
-import org.briarproject.bramble.api.transport.KeyManager;
-import org.briarproject.bramble.api.transport.StreamContext;
-import org.briarproject.bramble.api.transport.StreamReaderFactory;
-import org.briarproject.bramble.api.transport.StreamWriter;
-import org.briarproject.bramble.api.transport.StreamWriterFactory;
-
-import java.io.IOException;
-
-import static java.util.logging.Level.WARNING;
-import static org.briarproject.bramble.api.nullsafety.NullSafety.requireNonNull;
-import static org.briarproject.bramble.util.LogUtils.logException;
-
-@NotNullByDefault
-class OutgoingSimplexSyncConnection extends SyncConnection implements Runnable {
-
-	private final ContactId contactId;
-	private final TransportId transportId;
-	private final TransportConnectionWriter writer;
-
-	OutgoingSimplexSyncConnection(KeyManager keyManager,
-			ConnectionRegistry connectionRegistry,
-			StreamReaderFactory streamReaderFactory,
-			StreamWriterFactory streamWriterFactory,
-			SyncSessionFactory syncSessionFactory,
-			TransportPropertyManager transportPropertyManager,
-			ContactId contactId, TransportId transportId,
-			TransportConnectionWriter writer) {
-		super(keyManager, connectionRegistry, streamReaderFactory,
-				streamWriterFactory, syncSessionFactory,
-				transportPropertyManager);
-		this.contactId = contactId;
-		this.transportId = transportId;
-		this.writer = writer;
-	}
-
-	@Override
-	public void run() {
-		// Allocate a stream context
-		StreamContext ctx = allocateStreamContext(contactId, transportId);
-		if (ctx == null) {
-			LOG.warning("Could not allocate stream context");
-			onError();
-			return;
-		}
-		try {
-			// Create and run the outgoing session
-			createSimplexOutgoingSession(ctx, writer).run();
-			writer.dispose(false);
-		} catch (IOException e) {
-			logException(LOG, WARNING, e);
-			onError();
-		}
-	}
-
-	private void onError() {
-		disposeOnError(writer);
-	}
-
-	private SyncSession createSimplexOutgoingSession(StreamContext ctx,
-			TransportConnectionWriter w) throws IOException {
-		StreamWriter streamWriter = streamWriterFactory.createStreamWriter(
-				w.getOutputStream(), ctx);
-		ContactId c = requireNonNull(ctx.getContactId());
-		return syncSessionFactory.createSimplexOutgoingSession(c,
-				w.getMaxLatency(), streamWriter);
-	}
-}
-

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

@@ -1,64 +0,0 @@
-package org.briarproject.bramble.connection;
-
-import org.briarproject.bramble.api.connection.ConnectionRegistry;
-import org.briarproject.bramble.api.contact.ContactId;
-import org.briarproject.bramble.api.db.DbException;
-import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
-import org.briarproject.bramble.api.plugin.TransportConnectionReader;
-import org.briarproject.bramble.api.plugin.TransportId;
-import org.briarproject.bramble.api.properties.TransportPropertyManager;
-import org.briarproject.bramble.api.sync.PriorityHandler;
-import org.briarproject.bramble.api.sync.SyncSession;
-import org.briarproject.bramble.api.sync.SyncSessionFactory;
-import org.briarproject.bramble.api.transport.KeyManager;
-import org.briarproject.bramble.api.transport.StreamContext;
-import org.briarproject.bramble.api.transport.StreamReaderFactory;
-import org.briarproject.bramble.api.transport.StreamWriterFactory;
-
-import java.io.IOException;
-import java.io.InputStream;
-
-import javax.annotation.Nullable;
-
-import static java.util.logging.Level.WARNING;
-import static org.briarproject.bramble.api.nullsafety.NullSafety.requireNonNull;
-import static org.briarproject.bramble.util.LogUtils.logException;
-
-@NotNullByDefault
-class SyncConnection extends Connection {
-
-	final SyncSessionFactory syncSessionFactory;
-	final TransportPropertyManager transportPropertyManager;
-
-	SyncConnection(KeyManager keyManager, ConnectionRegistry connectionRegistry,
-			StreamReaderFactory streamReaderFactory,
-			StreamWriterFactory streamWriterFactory,
-			SyncSessionFactory syncSessionFactory,
-			TransportPropertyManager transportPropertyManager) {
-		super(keyManager, connectionRegistry, streamReaderFactory,
-				streamWriterFactory);
-		this.syncSessionFactory = syncSessionFactory;
-		this.transportPropertyManager = transportPropertyManager;
-	}
-
-	@Nullable
-	StreamContext allocateStreamContext(ContactId contactId,
-			TransportId transportId) {
-		try {
-			return keyManager.getStreamContext(contactId, transportId);
-		} catch (DbException e) {
-			logException(LOG, WARNING, e);
-			return null;
-		}
-	}
-
-	SyncSession createIncomingSession(StreamContext ctx,
-			TransportConnectionReader r, PriorityHandler handler)
-			throws IOException {
-		InputStream streamReader = streamReaderFactory.createStreamReader(
-				r.getInputStream(), ctx);
-		ContactId c = requireNonNull(ctx.getContactId());
-		return syncSessionFactory
-				.createIncomingSession(c, streamReader, handler);
-	}
-}

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

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

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

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

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

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

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

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

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

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

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

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

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

@@ -0,0 +1,694 @@
+package org.briarproject.bramble.plugin;
+
+import org.briarproject.bramble.api.contact.Contact;
+import org.briarproject.bramble.api.contact.ContactExchangeManager;
+import org.briarproject.bramble.api.contact.ContactId;
+import org.briarproject.bramble.api.contact.HandshakeManager;
+import org.briarproject.bramble.api.contact.HandshakeManager.HandshakeResult;
+import org.briarproject.bramble.api.contact.PendingContactId;
+import org.briarproject.bramble.api.db.DbException;
+import org.briarproject.bramble.api.lifecycle.IoExecutor;
+import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
+import org.briarproject.bramble.api.plugin.ConnectionManager;
+import org.briarproject.bramble.api.plugin.ConnectionRegistry;
+import org.briarproject.bramble.api.plugin.TransportConnectionReader;
+import org.briarproject.bramble.api.plugin.TransportConnectionWriter;
+import org.briarproject.bramble.api.plugin.TransportId;
+import org.briarproject.bramble.api.plugin.duplex.DuplexTransportConnection;
+import org.briarproject.bramble.api.sync.SyncSession;
+import org.briarproject.bramble.api.sync.SyncSessionFactory;
+import org.briarproject.bramble.api.transport.KeyManager;
+import org.briarproject.bramble.api.transport.StreamContext;
+import org.briarproject.bramble.api.transport.StreamReaderFactory;
+import org.briarproject.bramble.api.transport.StreamWriter;
+import org.briarproject.bramble.api.transport.StreamWriterFactory;
+
+import java.io.IOException;
+import java.io.InputStream;
+import java.util.concurrent.Executor;
+import java.util.logging.Logger;
+
+import javax.annotation.Nullable;
+import javax.inject.Inject;
+
+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.transport.TransportConstants.TAG_LENGTH;
+import static org.briarproject.bramble.util.IoUtils.read;
+import static org.briarproject.bramble.util.LogUtils.logException;
+
+@NotNullByDefault
+class ConnectionManagerImpl implements ConnectionManager {
+
+	private static final Logger LOG =
+			getLogger(ConnectionManagerImpl.class.getName());
+
+	private final Executor ioExecutor;
+	private final KeyManager keyManager;
+	private final StreamReaderFactory streamReaderFactory;
+	private final StreamWriterFactory streamWriterFactory;
+	private final SyncSessionFactory syncSessionFactory;
+	private final HandshakeManager handshakeManager;
+	private final ContactExchangeManager contactExchangeManager;
+	private final ConnectionRegistry connectionRegistry;
+
+	@Inject
+	ConnectionManagerImpl(@IoExecutor Executor ioExecutor,
+			KeyManager keyManager, StreamReaderFactory streamReaderFactory,
+			StreamWriterFactory streamWriterFactory,
+			SyncSessionFactory syncSessionFactory,
+			HandshakeManager handshakeManager,
+			ContactExchangeManager contactExchangeManager,
+			ConnectionRegistry connectionRegistry) {
+		this.ioExecutor = ioExecutor;
+		this.keyManager = keyManager;
+		this.streamReaderFactory = streamReaderFactory;
+		this.streamWriterFactory = streamWriterFactory;
+		this.syncSessionFactory = syncSessionFactory;
+		this.handshakeManager = handshakeManager;
+		this.contactExchangeManager = contactExchangeManager;
+		this.connectionRegistry = connectionRegistry;
+	}
+
+	@Override
+	public void manageIncomingConnection(TransportId t,
+			TransportConnectionReader r) {
+		ioExecutor.execute(new ManageIncomingSimplexConnection(t, r));
+	}
+
+	@Override
+	public void manageIncomingConnection(TransportId t,
+			DuplexTransportConnection d) {
+		ioExecutor.execute(new ManageIncomingDuplexConnection(t, d));
+	}
+
+	@Override
+	public void manageIncomingConnection(PendingContactId p, TransportId t,
+			DuplexTransportConnection d) {
+		ioExecutor.execute(new ManageIncomingHandshakeConnection(p, t, d));
+	}
+
+	@Override
+	public void manageOutgoingConnection(ContactId c, TransportId t,
+			TransportConnectionWriter w) {
+		ioExecutor.execute(new ManageOutgoingSimplexConnection(c, t, w));
+	}
+
+	@Override
+	public void manageOutgoingConnection(ContactId c, TransportId t,
+			DuplexTransportConnection d) {
+		ioExecutor.execute(new ManageOutgoingDuplexConnection(c, t, d));
+	}
+
+	@Override
+	public void manageOutgoingConnection(PendingContactId p, TransportId t,
+			DuplexTransportConnection d) {
+		ioExecutor.execute(new ManageOutgoingHandshakeConnection(p, t, d));
+	}
+
+	private byte[] readTag(InputStream in) throws IOException {
+		byte[] tag = new byte[TAG_LENGTH];
+		read(in, tag);
+		return tag;
+	}
+
+	private SyncSession createIncomingSession(StreamContext ctx,
+			TransportConnectionReader r) throws IOException {
+		InputStream streamReader = streamReaderFactory.createStreamReader(
+				r.getInputStream(), ctx);
+		ContactId c = requireNonNull(ctx.getContactId());
+		return syncSessionFactory.createIncomingSession(c, streamReader);
+	}
+
+	private SyncSession createSimplexOutgoingSession(StreamContext ctx,
+			TransportConnectionWriter w) throws IOException {
+		StreamWriter streamWriter = streamWriterFactory.createStreamWriter(
+				w.getOutputStream(), ctx);
+		ContactId c = requireNonNull(ctx.getContactId());
+		return syncSessionFactory.createSimplexOutgoingSession(c,
+				w.getMaxLatency(), streamWriter);
+	}
+
+	private SyncSession createDuplexOutgoingSession(StreamContext ctx,
+			TransportConnectionWriter w) throws IOException {
+		StreamWriter streamWriter = streamWriterFactory.createStreamWriter(
+				w.getOutputStream(), ctx);
+		ContactId c = requireNonNull(ctx.getContactId());
+		return syncSessionFactory.createDuplexOutgoingSession(c,
+				w.getMaxLatency(), w.getMaxIdleTime(), streamWriter);
+	}
+
+	private void disposeOnError(TransportConnectionReader reader,
+			boolean recognised) {
+		try {
+			reader.dispose(true, recognised);
+		} catch (IOException e) {
+			logException(LOG, WARNING, e);
+		}
+	}
+
+	private void disposeOnError(TransportConnectionWriter writer) {
+		try {
+			writer.dispose(true);
+		} catch (IOException e) {
+			logException(LOG, WARNING, e);
+		}
+	}
+
+	private class ManageIncomingSimplexConnection implements Runnable {
+
+		private final TransportId transportId;
+		private final TransportConnectionReader reader;
+
+		private ManageIncomingSimplexConnection(TransportId transportId,
+				TransportConnectionReader reader) {
+			this.transportId = transportId;
+			this.reader = reader;
+		}
+
+		@Override
+		public void run() {
+			// Read and recognise the tag
+			StreamContext ctx;
+			try {
+				byte[] tag = readTag(reader.getInputStream());
+				ctx = keyManager.getStreamContext(transportId, tag);
+			} catch (IOException | DbException e) {
+				logException(LOG, WARNING, e);
+				onError(false);
+				return;
+			}
+			if (ctx == null) {
+				LOG.info("Unrecognised tag");
+				onError(false);
+				return;
+			}
+			ContactId contactId = ctx.getContactId();
+			if (contactId == null) {
+				LOG.warning("Received rendezvous stream, expected contact");
+				onError(true);
+				return;
+			}
+			if (ctx.isHandshakeMode()) {
+				// TODO: Support handshake mode for contacts
+				LOG.warning("Received handshake tag, expected rotation mode");
+				onError(true);
+				return;
+			}
+			connectionRegistry.registerConnection(contactId, transportId, true);
+			try {
+				// Create and run the incoming session
+				createIncomingSession(ctx, reader).run();
+				reader.dispose(false, true);
+			} catch (IOException e) {
+				logException(LOG, WARNING, e);
+				onError(true);
+			} finally {
+				connectionRegistry.unregisterConnection(contactId, transportId,
+						true);
+			}
+		}
+
+		private void onError(boolean recognised) {
+			disposeOnError(reader, recognised);
+		}
+	}
+
+	private class ManageOutgoingSimplexConnection implements Runnable {
+
+		private final ContactId contactId;
+		private final TransportId transportId;
+		private final TransportConnectionWriter writer;
+
+		private ManageOutgoingSimplexConnection(ContactId contactId,
+				TransportId transportId, TransportConnectionWriter writer) {
+			this.contactId = contactId;
+			this.transportId = transportId;
+			this.writer = writer;
+		}
+
+		@Override
+		public void run() {
+			// Allocate a stream context
+			StreamContext ctx;
+			try {
+				ctx = keyManager.getStreamContext(contactId, transportId);
+			} catch (DbException e) {
+				logException(LOG, WARNING, e);
+				onError();
+				return;
+			}
+			if (ctx == null) {
+				LOG.warning("Could not allocate stream context");
+				onError();
+				return;
+			}
+			connectionRegistry.registerConnection(contactId, transportId,
+					false);
+			try {
+				// Create and run the outgoing session
+				createSimplexOutgoingSession(ctx, writer).run();
+				writer.dispose(false);
+			} catch (IOException e) {
+				logException(LOG, WARNING, e);
+				onError();
+			} finally {
+				connectionRegistry.unregisterConnection(contactId, transportId,
+						false);
+			}
+		}
+
+		private void onError() {
+			disposeOnError(writer);
+		}
+	}
+
+	private class ManageIncomingDuplexConnection implements Runnable {
+
+		private final TransportId transportId;
+		private final TransportConnectionReader reader;
+		private final TransportConnectionWriter writer;
+
+		@Nullable
+		private volatile SyncSession outgoingSession = null;
+
+		private ManageIncomingDuplexConnection(TransportId transportId,
+				DuplexTransportConnection connection) {
+			this.transportId = transportId;
+			reader = connection.getReader();
+			writer = connection.getWriter();
+		}
+
+		@Override
+		public void run() {
+			// Read and recognise the tag
+			StreamContext ctx;
+			try {
+				byte[] tag = readTag(reader.getInputStream());
+				ctx = keyManager.getStreamContext(transportId, tag);
+			} catch (IOException | DbException e) {
+				logException(LOG, WARNING, e);
+				onReadError(false);
+				return;
+			}
+			if (ctx == null) {
+				LOG.info("Unrecognised tag");
+				onReadError(false);
+				return;
+			}
+			ContactId contactId = ctx.getContactId();
+			if (contactId == null) {
+				LOG.warning("Expected contact tag, got rendezvous tag");
+				onReadError(true);
+				return;
+			}
+			if (ctx.isHandshakeMode()) {
+				// TODO: Support handshake mode for contacts
+				LOG.warning("Received handshake tag, expected rotation mode");
+				onReadError(true);
+				return;
+			}
+			connectionRegistry.registerConnection(contactId, transportId, true);
+			// Start the outgoing session on another thread
+			ioExecutor.execute(() -> runOutgoingSession(contactId));
+			try {
+				// Create and run the incoming session
+				createIncomingSession(ctx, reader).run();
+				reader.dispose(false, true);
+				// Interrupt the outgoing session so it finishes cleanly
+				SyncSession out = outgoingSession;
+				if (out != null) out.interrupt();
+			} catch (IOException e) {
+				logException(LOG, WARNING, e);
+				onReadError(true);
+			} finally {
+				connectionRegistry.unregisterConnection(contactId, transportId,
+						true);
+			}
+		}
+
+		private void runOutgoingSession(ContactId contactId) {
+			// Allocate a stream context
+			StreamContext ctx;
+			try {
+				ctx = keyManager.getStreamContext(contactId, transportId);
+			} catch (DbException e) {
+				logException(LOG, WARNING, e);
+				onWriteError();
+				return;
+			}
+			if (ctx == null) {
+				LOG.warning("Could not allocate stream context");
+				onWriteError();
+				return;
+			}
+			try {
+				// Create and run the outgoing session
+				SyncSession out = createDuplexOutgoingSession(ctx, writer);
+				outgoingSession = out;
+				out.run();
+				writer.dispose(false);
+			} catch (IOException e) {
+				logException(LOG, WARNING, e);
+				onWriteError();
+			}
+		}
+
+		private void onReadError(boolean recognised) {
+			disposeOnError(reader, recognised);
+			disposeOnError(writer);
+			// Interrupt the outgoing session so it finishes
+			SyncSession out = outgoingSession;
+			if (out != null) out.interrupt();
+		}
+
+		private void onWriteError() {
+			disposeOnError(reader, true);
+			disposeOnError(writer);
+		}
+	}
+
+	private class ManageOutgoingDuplexConnection implements Runnable {
+
+		private final ContactId contactId;
+		private final TransportId transportId;
+		private final TransportConnectionReader reader;
+		private final TransportConnectionWriter writer;
+
+		@Nullable
+		private volatile SyncSession outgoingSession = null;
+
+		private ManageOutgoingDuplexConnection(ContactId contactId,
+				TransportId transportId, DuplexTransportConnection connection) {
+			this.contactId = contactId;
+			this.transportId = transportId;
+			reader = connection.getReader();
+			writer = connection.getWriter();
+		}
+
+		@Override
+		public void run() {
+			// Allocate a stream context
+			StreamContext ctx;
+			try {
+				ctx = keyManager.getStreamContext(contactId, transportId);
+			} catch (DbException e) {
+				logException(LOG, WARNING, e);
+				onWriteError();
+				return;
+			}
+			if (ctx == null) {
+				LOG.warning("Could not allocate stream context");
+				onWriteError();
+				return;
+			}
+			if (ctx.isHandshakeMode()) {
+				// TODO: Support handshake mode for contacts
+				LOG.warning("Cannot use handshake mode stream context");
+				onWriteError();
+				return;
+			}
+			// Start the incoming session on another thread
+			ioExecutor.execute(this::runIncomingSession);
+			try {
+				// Create and run the outgoing session
+				SyncSession out = createDuplexOutgoingSession(ctx, writer);
+				outgoingSession = out;
+				out.run();
+				writer.dispose(false);
+			} catch (IOException e) {
+				logException(LOG, WARNING, e);
+				onWriteError();
+			}
+		}
+
+		private void runIncomingSession() {
+			// Read and recognise the tag
+			StreamContext ctx;
+			try {
+				byte[] tag = readTag(reader.getInputStream());
+				ctx = keyManager.getStreamContext(transportId, tag);
+			} catch (IOException | DbException e) {
+				logException(LOG, WARNING, e);
+				onReadError();
+				return;
+			}
+			// Unrecognised tags are suspicious in this case
+			if (ctx == null) {
+				LOG.warning("Unrecognised tag for returning stream");
+				onReadError();
+				return;
+			}
+			// Check that the stream comes from the expected contact
+			ContactId inContactId = ctx.getContactId();
+			if (inContactId == null) {
+				LOG.warning("Expected contact tag, got rendezvous tag");
+				onReadError();
+				return;
+			}
+			if (!contactId.equals(inContactId)) {
+				LOG.warning("Wrong contact ID for returning stream");
+				onReadError();
+				return;
+			}
+			if (ctx.isHandshakeMode()) {
+				// TODO: Support handshake mode for contacts
+				LOG.warning("Received handshake tag, expected rotation mode");
+				onReadError();
+				return;
+			}
+			connectionRegistry.registerConnection(contactId, transportId,
+					false);
+			try {
+				// Create and run the incoming session
+				createIncomingSession(ctx, reader).run();
+				reader.dispose(false, true);
+				// Interrupt the outgoing session so it finishes cleanly
+				SyncSession out = outgoingSession;
+				if (out != null) out.interrupt();
+			} catch (IOException e) {
+				logException(LOG, WARNING, e);
+				onReadError();
+			} finally {
+				connectionRegistry.unregisterConnection(contactId, transportId,
+						false);
+			}
+		}
+
+		private void onReadError() {
+			// 'Recognised' is always true for outgoing connections
+			disposeOnError(reader, true);
+			disposeOnError(writer);
+			// Interrupt the outgoing session so it finishes
+			SyncSession out = outgoingSession;
+			if (out != null) out.interrupt();
+		}
+
+		private void onWriteError() {
+			disposeOnError(reader, true);
+			disposeOnError(writer);
+		}
+	}
+
+	private class ManageIncomingHandshakeConnection implements Runnable {
+
+		private final PendingContactId pendingContactId;
+		private final TransportId transportId;
+		private final DuplexTransportConnection connection;
+		private final TransportConnectionReader reader;
+		private final TransportConnectionWriter writer;
+
+		private ManageIncomingHandshakeConnection(
+				PendingContactId pendingContactId, TransportId transportId,
+				DuplexTransportConnection connection) {
+			this.pendingContactId = pendingContactId;
+			this.transportId = transportId;
+			this.connection = connection;
+			reader = connection.getReader();
+			writer = connection.getWriter();
+		}
+
+		@Override
+		public void run() {
+			// Read and recognise the tag
+			StreamContext ctxIn;
+			try {
+				byte[] tag = readTag(reader.getInputStream());
+				ctxIn = keyManager.getStreamContext(transportId, tag);
+			} catch (IOException | DbException e) {
+				logException(LOG, WARNING, e);
+				onError(false);
+				return;
+			}
+			if (ctxIn == null) {
+				LOG.info("Unrecognised tag");
+				onError(false);
+				return;
+			}
+			PendingContactId inPendingContactId = ctxIn.getPendingContactId();
+			if (inPendingContactId == null) {
+				LOG.warning("Expected rendezvous tag, got contact tag");
+				onError(true);
+				return;
+			}
+			// Allocate the outgoing stream context
+			StreamContext ctxOut;
+			try {
+				ctxOut = keyManager.getStreamContext(pendingContactId,
+						transportId);
+			} catch (DbException e) {
+				logException(LOG, WARNING, e);
+				onError(true);
+				return;
+			}
+			if (ctxOut == null) {
+				LOG.warning("Could not allocate stream context");
+				onError(true);
+				return;
+			}
+			// Close the connection if it's redundant
+			if (!connectionRegistry.registerConnection(pendingContactId)) {
+				LOG.info("Redundant rendezvous connection");
+				onError(true);
+				return;
+			}
+			// Handshake and exchange contacts
+			try {
+				InputStream in = streamReaderFactory.createStreamReader(
+						reader.getInputStream(), ctxIn);
+				// Flush the output stream to send the outgoing stream header
+				StreamWriter out = streamWriterFactory.createStreamWriter(
+						writer.getOutputStream(), ctxOut);
+				out.getOutputStream().flush();
+				HandshakeResult result = handshakeManager.handshake(
+						pendingContactId, in, out);
+				Contact contact = contactExchangeManager.exchangeContacts(
+						pendingContactId, connection, result.getMasterKey(),
+						result.isAlice(), false);
+				connectionRegistry.unregisterConnection(pendingContactId, true);
+				// Reuse the connection as a transport connection
+				manageOutgoingConnection(contact.getId(), transportId,
+						connection);
+			} catch (IOException | DbException e) {
+				logException(LOG, WARNING, e);
+				onError(true);
+				connectionRegistry.unregisterConnection(pendingContactId,
+						false);
+			}
+		}
+
+		private void onError(boolean recognised) {
+			disposeOnError(reader, recognised);
+			disposeOnError(writer);
+		}
+	}
+
+	private class ManageOutgoingHandshakeConnection implements Runnable {
+
+		private final PendingContactId pendingContactId;
+		private final TransportId transportId;
+		private final DuplexTransportConnection connection;
+		private final TransportConnectionReader reader;
+		private final TransportConnectionWriter writer;
+
+		private ManageOutgoingHandshakeConnection(
+				PendingContactId pendingContactId, TransportId transportId,
+				DuplexTransportConnection connection) {
+			this.pendingContactId = pendingContactId;
+			this.transportId = transportId;
+			this.connection = connection;
+			reader = connection.getReader();
+			writer = connection.getWriter();
+		}
+
+		@Override
+		public void run() {
+			// Allocate the outgoing stream context
+			StreamContext ctxOut;
+			try {
+				ctxOut = keyManager.getStreamContext(pendingContactId,
+						transportId);
+			} catch (DbException e) {
+				logException(LOG, WARNING, e);
+				onError();
+				return;
+			}
+			if (ctxOut == null) {
+				LOG.warning("Could not allocate stream context");
+				onError();
+				return;
+			}
+			// Flush the output stream to send the outgoing stream header
+			StreamWriter out;
+			try {
+				out = streamWriterFactory.createStreamWriter(
+						writer.getOutputStream(), ctxOut);
+				out.getOutputStream().flush();
+			} catch (IOException e) {
+				logException(LOG, WARNING, e);
+				onError();
+				return;
+			}
+			// Read and recognise the tag
+			StreamContext ctxIn;
+			try {
+				byte[] tag = readTag(reader.getInputStream());
+				ctxIn = keyManager.getStreamContext(transportId, tag);
+			} catch (IOException | DbException e) {
+				logException(LOG, WARNING, e);
+				onError();
+				return;
+			}
+			// Unrecognised tags are suspicious in this case
+			if (ctxIn == null) {
+				LOG.warning("Unrecognised tag for returning stream");
+				onError();
+				return;
+			}
+			// Check that the stream comes from the expected pending contact
+			PendingContactId inPendingContactId = ctxIn.getPendingContactId();
+			if (inPendingContactId == null) {
+				LOG.warning("Expected rendezvous tag, got contact tag");
+				onError();
+				return;
+			}
+			if (!inPendingContactId.equals(pendingContactId)) {
+				LOG.warning("Wrong pending contact ID for returning stream");
+				onError();
+				return;
+			}
+			// Close the connection if it's redundant
+			if (!connectionRegistry.registerConnection(pendingContactId)) {
+				LOG.info("Redundant rendezvous connection");
+				onError();
+				return;
+			}
+			// Handshake and exchange contacts
+			try {
+				InputStream in = streamReaderFactory.createStreamReader(
+						reader.getInputStream(), ctxIn);
+				HandshakeResult result = handshakeManager.handshake(
+						pendingContactId, in, out);
+				Contact contact = contactExchangeManager.exchangeContacts(
+						pendingContactId, connection, result.getMasterKey(),
+						result.isAlice(), false);
+				connectionRegistry.unregisterConnection(pendingContactId, true);
+				// Reuse the connection as a transport connection
+				manageOutgoingConnection(contact.getId(), transportId,
+						connection);
+			} catch (IOException | DbException e) {
+				logException(LOG, WARNING, e);
+				onError();
+				connectionRegistry.unregisterConnection(pendingContactId,
+						false);
+			}
+		}
+
+		private void onError() {
+			// 'Recognised' is always true for outgoing connections
+			disposeOnError(reader, true);
+			disposeOnError(writer);
+		}
+	}
+}

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

@@ -0,0 +1,150 @@
+package org.briarproject.bramble.plugin;
+
+import org.briarproject.bramble.api.Multiset;
+import org.briarproject.bramble.api.contact.ContactId;
+import org.briarproject.bramble.api.contact.PendingContactId;
+import org.briarproject.bramble.api.event.EventBus;
+import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
+import org.briarproject.bramble.api.plugin.ConnectionRegistry;
+import org.briarproject.bramble.api.plugin.TransportId;
+import org.briarproject.bramble.api.plugin.event.ConnectionClosedEvent;
+import org.briarproject.bramble.api.plugin.event.ConnectionOpenedEvent;
+import org.briarproject.bramble.api.plugin.event.ContactConnectedEvent;
+import org.briarproject.bramble.api.plugin.event.ContactDisconnectedEvent;
+import org.briarproject.bramble.api.rendezvous.event.RendezvousConnectionClosedEvent;
+import org.briarproject.bramble.api.rendezvous.event.RendezvousConnectionOpenedEvent;
+
+import java.util.ArrayList;
+import java.util.Collection;
+import java.util.Collections;
+import java.util.HashMap;
+import java.util.HashSet;
+import java.util.List;
+import java.util.Map;
+import java.util.Set;
+import java.util.logging.Logger;
+
+import javax.annotation.concurrent.GuardedBy;
+import javax.annotation.concurrent.ThreadSafe;
+import javax.inject.Inject;
+
+import static java.util.logging.Level.INFO;
+import static java.util.logging.Logger.getLogger;
+
+@ThreadSafe
+@NotNullByDefault
+class ConnectionRegistryImpl implements ConnectionRegistry {
+
+	private static final Logger LOG =
+			getLogger(ConnectionRegistryImpl.class.getName());
+
+	private final EventBus eventBus;
+
+	private final Object lock = new Object();
+	@GuardedBy("lock")
+	private final Map<TransportId, Multiset<ContactId>> contactConnections;
+	@GuardedBy("lock")
+	private final Multiset<ContactId> contactCounts;
+	@GuardedBy("lock")
+	private final Set<PendingContactId> connectedPendingContacts;
+
+	@Inject
+	ConnectionRegistryImpl(EventBus eventBus) {
+		this.eventBus = eventBus;
+		contactConnections = new HashMap<>();
+		contactCounts = new Multiset<>();
+		connectedPendingContacts = new HashSet<>();
+	}
+
+	@Override
+	public void registerConnection(ContactId c, TransportId t,
+			boolean incoming) {
+		if (LOG.isLoggable(INFO)) {
+			if (incoming) LOG.info("Incoming connection registered: " + t);
+			else LOG.info("Outgoing connection registered: " + t);
+		}
+		boolean firstConnection = false;
+		synchronized (lock) {
+			Multiset<ContactId> m = contactConnections.get(t);
+			if (m == null) {
+				m = new Multiset<>();
+				contactConnections.put(t, m);
+			}
+			m.add(c);
+			if (contactCounts.add(c) == 1) firstConnection = true;
+		}
+		eventBus.broadcast(new ConnectionOpenedEvent(c, t, incoming));
+		if (firstConnection) {
+			LOG.info("Contact connected");
+			eventBus.broadcast(new ContactConnectedEvent(c));
+		}
+	}
+
+	@Override
+	public void unregisterConnection(ContactId c, TransportId t,
+			boolean incoming) {
+		if (LOG.isLoggable(INFO)) {
+			if (incoming) LOG.info("Incoming connection unregistered: " + t);
+			else LOG.info("Outgoing connection unregistered: " + t);
+		}
+		boolean lastConnection = false;
+		synchronized (lock) {
+			Multiset<ContactId> m = contactConnections.get(t);
+			if (m == null || !m.contains(c))
+				throw new IllegalArgumentException();
+			m.remove(c);
+			if (contactCounts.remove(c) == 0) lastConnection = true;
+		}
+		eventBus.broadcast(new ConnectionClosedEvent(c, t, incoming));
+		if (lastConnection) {
+			LOG.info("Contact disconnected");
+			eventBus.broadcast(new ContactDisconnectedEvent(c));
+		}
+	}
+
+	@Override
+	public Collection<ContactId> getConnectedContacts(TransportId t) {
+		synchronized (lock) {
+			Multiset<ContactId> m = contactConnections.get(t);
+			if (m == null) return Collections.emptyList();
+			List<ContactId> ids = new ArrayList<>(m.keySet());
+			if (LOG.isLoggable(INFO))
+				LOG.info(ids.size() + " contacts connected: " + t);
+			return ids;
+		}
+	}
+
+	@Override
+	public boolean isConnected(ContactId c, TransportId t) {
+		synchronized (lock) {
+			Multiset<ContactId> m = contactConnections.get(t);
+			return m != null && m.contains(c);
+		}
+	}
+
+	@Override
+	public boolean isConnected(ContactId c) {
+		synchronized (lock) {
+			return contactCounts.contains(c);
+		}
+	}
+
+	@Override
+	public boolean registerConnection(PendingContactId p) {
+		boolean added;
+		synchronized (lock) {
+			added = connectedPendingContacts.add(p);
+		}
+		if (added) eventBus.broadcast(new RendezvousConnectionOpenedEvent(p));
+		return added;
+	}
+
+	@Override
+	public void unregisterConnection(PendingContactId p, boolean success) {
+		synchronized (lock) {
+			if (!connectedPendingContacts.remove(p))
+				throw new IllegalArgumentException();
+		}
+		eventBus.broadcast(new RendezvousConnectionClosedEvent(p, success));
+	}
+}

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

@@ -1,13 +1,14 @@
 package org.briarproject.bramble.plugin;
 
-import org.briarproject.bramble.api.connection.ConnectionManager;
 import org.briarproject.bramble.api.db.DbException;
 import org.briarproject.bramble.api.event.EventBus;
 import org.briarproject.bramble.api.lifecycle.IoExecutor;
 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.ConnectionManager;
 import org.briarproject.bramble.api.plugin.Plugin;
+import org.briarproject.bramble.api.plugin.Plugin.State;
 import org.briarproject.bramble.api.plugin.PluginCallback;
 import org.briarproject.bramble.api.plugin.PluginConfig;
 import org.briarproject.bramble.api.plugin.PluginException;
@@ -18,8 +19,9 @@ 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.TransportEnabledEvent;
+import org.briarproject.bramble.api.plugin.event.TransportActiveEvent;
+import org.briarproject.bramble.api.plugin.event.TransportInactiveEvent;
+import org.briarproject.bramble.api.plugin.event.TransportStateEvent;
 import org.briarproject.bramble.api.plugin.simplex.SimplexPlugin;
 import org.briarproject.bramble.api.plugin.simplex.SimplexPluginFactory;
 import org.briarproject.bramble.api.properties.TransportProperties;
@@ -36,6 +38,7 @@ 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;
@@ -45,6 +48,9 @@ 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.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;
@@ -177,6 +183,26 @@ class PluginManagerImpl implements PluginManager, Service {
 		return supported;
 	}
 
+	@Override
+	public void setPluginEnabled(TransportId t, boolean enabled) {
+		Plugin plugin = plugins.get(t);
+		if (plugin == null) return;
+
+		Settings s = new Settings();
+		s.putBoolean(PREF_PLUGIN_ENABLE, enabled);
+		ioExecutor.execute(() -> mergeSettings(s, t.getString()));
+	}
+
+	private void mergeSettings(Settings s, String namespace) {
+		try {
+			long start = now();
+			settingsManager.mergeSettings(s, namespace);
+			logDuration(LOG, "Merging settings", start);
+		} catch (DbException e) {
+			logException(LOG, WARNING, e);
+		}
+	}
+
 	private class PluginStarter implements Runnable {
 
 		private final Plugin plugin;
@@ -250,7 +276,8 @@ 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;
@@ -278,11 +305,7 @@ class PluginManagerImpl implements PluginManager, Service {
 
 		@Override
 		public void mergeSettings(Settings s) {
-			try {
-				settingsManager.mergeSettings(s, id.getString());
-			} catch (DbException e) {
-				logException(LOG, WARNING, e);
-			}
+			PluginManagerImpl.this.mergeSettings(s, id.getString());
 		}
 
 		@Override
@@ -295,15 +318,20 @@ class PluginManagerImpl implements PluginManager, Service {
 		}
 
 		@Override
-		public void transportEnabled() {
-			if (!enabled.getAndSet(true))
-				eventBus.broadcast(new TransportEnabledEvent(id));
-		}
-
-		@Override
-		public void transportDisabled() {
-			if (enabled.getAndSet(false))
-				eventBus.broadcast(new TransportDisabledEvent(id));
+		public void pluginStateChanged(State newState) {
+			State oldState = state.getAndSet(newState);
+			if (newState != oldState) {
+				if (LOG.isLoggable(INFO)) {
+					LOG.info(id + " changed from state " + oldState
+							+ " to " + newState);
+				}
+				eventBus.broadcast(new TransportStateEvent(id, newState));
+				if (newState == ACTIVE) {
+					eventBus.broadcast(new TransportActiveEvent(id));
+				} else if (oldState == ACTIVE) {
+					eventBus.broadcast(new TransportInactiveEvent(id));
+				}
+			}
 		}
 
 		@Override

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

@@ -3,6 +3,8 @@ package org.briarproject.bramble.plugin;
 import org.briarproject.bramble.api.event.EventBus;
 import org.briarproject.bramble.api.lifecycle.LifecycleManager;
 import org.briarproject.bramble.api.plugin.BackoffFactory;
+import org.briarproject.bramble.api.plugin.ConnectionManager;
+import org.briarproject.bramble.api.plugin.ConnectionRegistry;
 import org.briarproject.bramble.api.plugin.PluginConfig;
 import org.briarproject.bramble.api.plugin.PluginManager;
 
@@ -27,6 +29,20 @@ public class PluginModule {
 		return new BackoffFactoryImpl();
 	}
 
+	@Provides
+	@Singleton
+	ConnectionManager provideConnectionManager(
+			ConnectionManagerImpl connectionManager) {
+		return connectionManager;
+	}
+
+	@Provides
+	@Singleton
+	ConnectionRegistry provideConnectionRegistry(
+			ConnectionRegistryImpl connectionRegistry) {
+		return connectionRegistry;
+	}
+
 	@Provides
 	@Singleton
 	PluginManager providePluginManager(LifecycleManager lifecycleManager,

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

@@ -1,8 +1,6 @@
 package org.briarproject.bramble.plugin;
 
 import org.briarproject.bramble.api.Pair;
-import org.briarproject.bramble.api.connection.ConnectionManager;
-import org.briarproject.bramble.api.connection.ConnectionRegistry;
 import org.briarproject.bramble.api.contact.ContactId;
 import org.briarproject.bramble.api.contact.event.ContactAddedEvent;
 import org.briarproject.bramble.api.db.DbException;
@@ -11,6 +9,9 @@ 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.ConnectionHandler;
+import org.briarproject.bramble.api.plugin.ConnectionManager;
+import org.briarproject.bramble.api.plugin.ConnectionRegistry;
+import org.briarproject.bramble.api.plugin.DiscoveryHandler;
 import org.briarproject.bramble.api.plugin.Plugin;
 import org.briarproject.bramble.api.plugin.PluginManager;
 import org.briarproject.bramble.api.plugin.TransportConnectionReader;
@@ -20,8 +21,8 @@ import org.briarproject.bramble.api.plugin.duplex.DuplexPlugin;
 import org.briarproject.bramble.api.plugin.duplex.DuplexTransportConnection;
 import org.briarproject.bramble.api.plugin.event.ConnectionClosedEvent;
 import org.briarproject.bramble.api.plugin.event.ConnectionOpenedEvent;
-import org.briarproject.bramble.api.plugin.event.TransportDisabledEvent;
-import org.briarproject.bramble.api.plugin.event.TransportEnabledEvent;
+import org.briarproject.bramble.api.plugin.event.TransportActiveEvent;
+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;
@@ -32,6 +33,7 @@ import java.security.SecureRandom;
 import java.util.ArrayList;
 import java.util.Collection;
 import java.util.HashMap;
+import java.util.List;
 import java.util.Map;
 import java.util.Map.Entry;
 import java.util.concurrent.Executor;
@@ -98,21 +100,21 @@ class PollerImpl implements Poller, EventListener {
 			ConnectionClosedEvent c = (ConnectionClosedEvent) e;
 			// Reschedule polling, the polling interval may have decreased
 			reschedule(c.getTransportId());
-			// If an outgoing connection failed, try to reconnect
-			if (!c.isIncoming() && c.isException()) {
+			if (!c.isIncoming()) {
+				// Connect to the disconnected contact
 				connectToContact(c.getContactId(), c.getTransportId());
 			}
 		} else if (e instanceof ConnectionOpenedEvent) {
 			ConnectionOpenedEvent c = (ConnectionOpenedEvent) e;
 			// Reschedule polling, the polling interval may have decreased
 			reschedule(c.getTransportId());
-		} else if (e instanceof TransportEnabledEvent) {
-			TransportEnabledEvent t = (TransportEnabledEvent) e;
-			// Poll the newly enabled transport
+		} else if (e instanceof TransportActiveEvent) {
+			TransportActiveEvent t = (TransportActiveEvent) e;
+			// Poll the newly activated transport
 			pollNow(t.getTransportId());
-		} else if (e instanceof TransportDisabledEvent) {
-			TransportDisabledEvent t = (TransportDisabledEvent) e;
-			// Cancel polling for the disabled transport
+		} else if (e instanceof TransportInactiveEvent) {
+			TransportInactiveEvent t = (TransportInactiveEvent) e;
+			// Cancel polling for the deactivated transport
 			cancel(t.getTransportId());
 		}
 	}
@@ -210,18 +212,20 @@ class PollerImpl implements Poller, EventListener {
 	@IoExecutor
 	private void poll(Plugin p) {
 		TransportId t = p.getId();
-		if (LOG.isLoggable(INFO)) LOG.info("Polling plugin " + t);
+		if (LOG.isLoggable(INFO)) LOG.info("Polling " + t);
 		try {
 			Map<ContactId, TransportProperties> remote =
 					transportPropertyManager.getRemoteProperties(t);
 			Collection<ContactId> connected =
-					connectionRegistry.getConnectedOrBetterContacts(t);
-			Collection<Pair<TransportProperties, ConnectionHandler>>
-					properties = new ArrayList<>();
+					connectionRegistry.getConnectedContacts(t);
+			List<Pair<TransportProperties, ConnectionHandler>> properties =
+					new ArrayList<>();
 			for (Entry<ContactId, TransportProperties> e : remote.entrySet()) {
 				ContactId c = e.getKey();
-				if (!connected.contains(c))
-					properties.add(new Pair<>(e.getValue(), new Handler(c, t)));
+				if (!connected.contains(c)) {
+					ConnHandler handler = new ConnHandler(c, t);
+					properties.add(new Pair<>(e.getValue(), handler));
+				}
 			}
 			if (!properties.isEmpty()) p.poll(properties);
 		} catch (DbException e) {
@@ -229,6 +233,30 @@ class PollerImpl implements Poller, EventListener {
 		}
 	}
 
+	@IoExecutor
+	private void discover(DuplexPlugin p) {
+		TransportId t = p.getId();
+		if (LOG.isLoggable(INFO)) LOG.info("Discovering peers for " + t);
+		try {
+			Map<ContactId, TransportProperties> remote =
+					transportPropertyManager.getRemoteProperties(t);
+			Collection<ContactId> connected =
+					connectionRegistry.getConnectedContacts(t);
+			List<Pair<TransportProperties, DiscoveryHandler>> properties =
+					new ArrayList<>();
+			for (Entry<ContactId, TransportProperties> e : remote.entrySet()) {
+				ContactId c = e.getKey();
+				if (!connected.contains(c)) {
+					DiscoHandler handler = new DiscoHandler(c, p);
+					properties.add(new Pair<>(e.getValue(), handler));
+				}
+			}
+			if (!properties.isEmpty()) p.discoverPeers(properties);
+		} catch (DbException e) {
+			logException(LOG, WARNING, e);
+		}
+	}
+
 	private class ScheduledPollTask {
 
 		private final PollTask task;
@@ -268,16 +296,23 @@ class PollerImpl implements Poller, EventListener {
 			int delay = plugin.getPollingInterval();
 			if (randomiseNext) delay = (int) (delay * random.nextDouble());
 			schedule(plugin, delay, false);
-			poll(plugin);
+			// FIXME: Revert
+			if (plugin instanceof DuplexPlugin) {
+				DuplexPlugin d = (DuplexPlugin) plugin;
+				if (d.supportsDiscovery()) discover(d);
+				else poll(d);
+			} else {
+				poll(plugin);
+			}
 		}
 	}
 
-	private class Handler implements ConnectionHandler {
+	private class ConnHandler implements ConnectionHandler {
 
 		private final ContactId contactId;
 		private final TransportId transportId;
 
-		private Handler(ContactId contactId, TransportId transportId) {
+		private ConnHandler(ContactId contactId, TransportId transportId) {
 			this.contactId = contactId;
 			this.transportId = transportId;
 		}
@@ -300,4 +335,27 @@ class PollerImpl implements Poller, EventListener {
 					transportId, w);
 		}
 	}
+
+	private class DiscoHandler implements DiscoveryHandler {
+
+		private final ContactId contactId;
+		private final DuplexPlugin plugin;
+
+		private DiscoHandler(ContactId contactId, DuplexPlugin plugin) {
+			this.contactId = contactId;
+			this.plugin = plugin;
+		}
+
+		@Override
+		public void handleDevice(TransportProperties p) {
+			LOG.info("Discovered contact via " + plugin.getId());
+			ioExecutor.execute(() -> {
+				DuplexTransportConnection c = plugin.createConnection(p);
+				if (c != null) {
+					connectionManager.manageOutgoingConnection(contactId,
+							plugin.getId(), c);
+				}
+			});
+		}
+	}
 }

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

@@ -5,15 +5,17 @@ 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;
+import org.briarproject.bramble.api.plugin.DiscoveryHandler;
 import org.briarproject.bramble.api.plugin.PluginCallback;
 import org.briarproject.bramble.api.plugin.PluginException;
 import org.briarproject.bramble.api.plugin.TransportId;
@@ -30,23 +32,28 @@ import org.briarproject.bramble.api.settings.event.SettingsUpdatedEvent;
 
 import java.io.IOException;
 import java.security.SecureRandom;
-import java.util.Collection;
+import java.util.List;
 import java.util.UUID;
 import java.util.concurrent.Executor;
 import java.util.concurrent.atomic.AtomicBoolean;
 import java.util.logging.Logger;
 
 import javax.annotation.Nullable;
+import javax.annotation.concurrent.GuardedBy;
+import javax.annotation.concurrent.ThreadSafe;
 
 import static java.util.logging.Level.INFO;
 import static java.util.logging.Level.WARNING;
 import static java.util.logging.Logger.getLogger;
 import static org.briarproject.bramble.api.keyagreement.KeyAgreementConstants.TRANSPORT_ID_BLUETOOTH;
 import static org.briarproject.bramble.api.plugin.BluetoothConstants.ID;
-import static org.briarproject.bramble.api.plugin.BluetoothConstants.PREF_BT_ENABLE;
 import static org.briarproject.bramble.api.plugin.BluetoothConstants.PROP_ADDRESS;
 import static org.briarproject.bramble.api.plugin.BluetoothConstants.PROP_UUID;
 import static org.briarproject.bramble.api.plugin.BluetoothConstants.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.util.LogUtils.logException;
 import static org.briarproject.bramble.util.PrivacyUtils.scrubMacAddress;
 import static org.briarproject.bramble.util.StringUtils.isNullOrEmpty;
@@ -61,18 +68,17 @@ abstract class BluetoothPlugin<SS> implements DuplexPlugin, EventListener {
 			getLogger(BluetoothPlugin.class.getName());
 
 	final BluetoothConnectionLimiter connectionLimiter;
-	final TimeoutMonitor timeoutMonitor;
 
 	private final Executor ioExecutor;
 	private final SecureRandom secureRandom;
 	private final Backoff backoff;
 	private final PluginCallback callback;
-	private final int maxLatency, maxIdleTime;
+	private final int maxLatency;
 	private final AtomicBoolean used = new AtomicBoolean(false);
 
-	private volatile boolean running = false, contactConnections = false;
+	protected final PluginState state = new PluginState();
+
 	private volatile String contactConnectionsUuid = null;
-	private volatile SS socket = null;
 
 	abstract void initialiseAdapter() throws IOException;
 
@@ -107,31 +113,32 @@ abstract class BluetoothPlugin<SS> implements DuplexPlugin, EventListener {
 	abstract DuplexTransportConnection discoverAndConnect(String uuid);
 
 	BluetoothPlugin(BluetoothConnectionLimiter connectionLimiter,
-			TimeoutMonitor timeoutMonitor, Executor ioExecutor,
-			SecureRandom secureRandom, Backoff backoff,
-			PluginCallback callback, int maxLatency, int maxIdleTime) {
+			Executor ioExecutor, SecureRandom secureRandom,
+			Backoff backoff, PluginCallback callback, int maxLatency) {
 		this.connectionLimiter = connectionLimiter;
-		this.timeoutMonitor = timeoutMonitor;
 		this.ioExecutor = ioExecutor;
 		this.secureRandom = secureRandom;
 		this.backoff = backoff;
 		this.callback = callback;
 		this.maxLatency = maxLatency;
-		this.maxIdleTime = maxIdleTime;
 	}
 
 	void onAdapterEnabled() {
 		LOG.info("Bluetooth enabled");
 		// We may not have been able to get the local address before
 		ioExecutor.execute(this::updateProperties);
-		if (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
@@ -146,37 +153,31 @@ abstract class BluetoothPlugin<SS> implements DuplexPlugin, EventListener {
 
 	@Override
 	public int getMaxIdleTime() {
-		return maxIdleTime;
+		// Bluetooth detects dead connections so we don't need keepalives
+		return Integer.MAX_VALUE;
 	}
 
 	@Override
 	public void start() throws PluginException {
 		if (used.getAndSet(true)) throw new IllegalStateException();
+		Settings settings = callback.getSettings();
+		boolean enabledByUser = settings.getBoolean(PREF_PLUGIN_ENABLE, false);
+		state.setStarted(enabledByUser);
 		try {
 			initialiseAdapter();
 		} catch (IOException e) {
 			throw new PluginException(e);
 		}
 		updateProperties();
-		running = true;
-		loadSettings(callback.getSettings());
-		if (shouldAllowContactConnections()) {
+		if (enabledByUser) {
 			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 +186,13 @@ 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();
+			acceptContactConnections(ss);
 		});
 	}
 
@@ -221,36 +221,39 @@ abstract class BluetoothPlugin<SS> implements DuplexPlugin, EventListener {
 		if (changed) callback.mergeLocalProperties(p);
 	}
 
-	private void acceptContactConnections() {
+	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
-				if (LOG.isLoggable(INFO)) LOG.info(e.toString());
+				// This is expected when the server socket is closed
+				LOG.info("Server socket closed");
+				state.clearServerSocket();
 				return;
 			}
 			LOG.info("Connection received");
-			if (connectionLimiter.contactConnectionOpened(conn)) {
-				backoff.reset();
+			backoff.reset();
+			if (connectionLimiter.contactConnectionOpened(conn))
 				callback.handleConnection(conn);
-			}
-			if (!running) return;
 		}
 	}
 
 	@Override
 	public void stop() {
-		running = false;
-		tryToClose(socket);
-		callback.transportDisabled();
+		SS ss = state.setStopped();
+		tryToClose(ss);
 		disableAdapterIfEnabledByUs();
 	}
 
 	@Override
-	public boolean isRunning() {
-		return running && isAdapterEnabled();
+	public State getState() {
+		return state.getState();
+	}
+
+	@Override
+	public int getReasonsDisabled() {
+		return state.getReasonsDisabled();
 	}
 
 	@Override
@@ -264,9 +267,9 @@ abstract class BluetoothPlugin<SS> implements DuplexPlugin, EventListener {
 	}
 
 	@Override
-	public void poll(Collection<Pair<TransportProperties, ConnectionHandler>>
-			properties) {
-		if (!isRunning() || !shouldAllowContactConnections()) return;
+	public void poll(
+			List<Pair<TransportProperties, ConnectionHandler>> properties) {
+		if (getState() != ACTIVE) return;
 		backoff.increment();
 		for (Pair<TransportProperties, ConnectionHandler> p : properties) {
 			connect(p.getFirst(), p.getSecond());
@@ -279,10 +282,13 @@ abstract class BluetoothPlugin<SS> implements DuplexPlugin, EventListener {
 		String uuid = p.get(PROP_UUID);
 		if (isNullOrEmpty(uuid)) return;
 		ioExecutor.execute(() -> {
+			if (getState() != ACTIVE) return;
+			if (!connectionLimiter.canOpenContactConnection()) return;
 			DuplexTransportConnection d = createConnection(p);
 			if (d != null) {
 				backoff.reset();
-				h.handleConnection(d);
+				if (connectionLimiter.contactConnectionOpened(d))
+					h.handleConnection(d);
 			}
 		});
 	}
@@ -320,7 +326,7 @@ 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;
@@ -328,6 +334,7 @@ abstract class BluetoothPlugin<SS> implements DuplexPlugin, EventListener {
 		if (isNullOrEmpty(uuid)) return null;
 		DuplexTransportConnection conn = connect(address, uuid);
 		if (conn == null) return null;
+		// TODO: Why don't we reset the backoff here?
 		return connectionLimiter.contactConnectionOpened(conn) ? conn : null;
 	}
 
@@ -338,7 +345,7 @@ 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);
@@ -350,7 +357,7 @@ abstract class BluetoothPlugin<SS> implements DuplexPlugin, EventListener {
 			logException(LOG, WARNING, e);
 			return null;
 		}
-		if (!isRunning()) {
+		if (getState() != ACTIVE) {
 			tryToClose(ss);
 			return null;
 		}
@@ -364,7 +371,7 @@ 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;
@@ -405,6 +412,17 @@ abstract class BluetoothPlugin<SS> implements DuplexPlugin, EventListener {
 		throw new UnsupportedOperationException();
 	}
 
+	@Override
+	public boolean supportsDiscovery() {
+		return false;
+	}
+
+	@Override
+	public void discoverPeers(
+			List<Pair<TransportProperties, DiscoveryHandler>> properties) {
+		throw new UnsupportedOperationException();
+	}
+
 	@Override
 	public void eventOccurred(Event e) {
 		if (e instanceof EnableBluetoothEvent) {
@@ -424,17 +442,17 @@ abstract class BluetoothPlugin<SS> implements DuplexPlugin, EventListener {
 		}
 	}
 
+	@IoExecutor
 	private void onSettingsUpdated(Settings settings) {
-		boolean wasAllowed = shouldAllowContactConnections();
-		loadSettings(settings);
-		boolean isAllowed = shouldAllowContactConnections();
-		if (wasAllowed && !isAllowed) {
-			LOG.info("Contact connections disabled");
-			tryToClose(socket);
-			callback.transportDisabled();
+		boolean enabledByUser = settings.getBoolean(PREF_PLUGIN_ENABLE, false);
+		SS ss = state.setEnabledByUser(enabledByUser);
+		State s = getState();
+		if (ss != null) {
+			LOG.info("Disabled by user, closing server socket");
+			tryToClose(ss);
 			disableAdapterIfEnabledByUs();
-		} else if (!wasAllowed && isAllowed) {
-			LOG.info("Contact connections enabled");
+		} else if (s == INACTIVE) {
+			LOG.info("Enabled by user, opening server socket");
 			if (isAdapterEnabled()) bind();
 			else enableAdapter();
 		}
@@ -462,4 +480,70 @@ 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

@@ -11,7 +11,6 @@ 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;
@@ -41,6 +40,7 @@ import static org.briarproject.bramble.api.plugin.LanTcpConstants.PREF_LAN_IP_PO
 import static org.briarproject.bramble.api.plugin.LanTcpConstants.PROP_IP_PORTS;
 import static org.briarproject.bramble.api.plugin.LanTcpConstants.PROP_PORT;
 import static org.briarproject.bramble.util.ByteUtils.MAX_16_BIT_UNSIGNED;
+import static org.briarproject.bramble.util.IoUtils.tryToClose;
 import static org.briarproject.bramble.util.PrivacyUtils.scrubSocketAddress;
 import static org.briarproject.bramble.util.StringUtils.isNullOrEmpty;
 import static org.briarproject.bramble.util.StringUtils.join;
@@ -91,7 +91,8 @@ 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, false));
 		bind();
 	}
 
@@ -271,10 +272,10 @@ 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()) {
+		if (ss == null) {
 			LOG.info("Could not bind server socket for key agreement");
 			return null;
 		}
@@ -290,8 +291,8 @@ class LanTcpPlugin extends TcpPlugin {
 	@Override
 	public DuplexTransportConnection createKeyAgreementConnection(
 			byte[] commitment, BdfList descriptor) {
-		if (!isRunning()) return null;
-		ServerSocket ss = socket;
+		ServerSocket ss = state.getServerSocket();
+		if (ss == null) return null;
 		InterfaceAddress local = getLocalInterfaceAddress(ss.getInetAddress());
 		if (local == null) {
 			LOG.warning("No interface for key agreement server socket");
@@ -363,7 +364,7 @@ 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 +1,6 @@
 package org.briarproject.bramble.plugin.tcp;
 
+import org.briarproject.bramble.api.event.EventBus;
 import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
 import org.briarproject.bramble.api.plugin.Backoff;
 import org.briarproject.bramble.api.plugin.BackoffFactory;
@@ -26,11 +27,13 @@ public class LanTcpPluginFactory implements DuplexPluginFactory {
 	private static final double BACKOFF_BASE = 1.2;
 
 	private final Executor ioExecutor;
+	private final EventBus eventBus;
 	private final BackoffFactory backoffFactory;
 
-	public LanTcpPluginFactory(Executor ioExecutor,
+	public LanTcpPluginFactory(Executor ioExecutor, EventBus eventBus,
 			BackoffFactory backoffFactory) {
 		this.ioExecutor = ioExecutor;
+		this.eventBus = eventBus;
 		this.backoffFactory = backoffFactory;
 	}
 
@@ -48,7 +51,9 @@ 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, backoff, callback, MAX_LATENCY,
 				MAX_IDLE_TIME, CONNECTION_TIMEOUT);
+		eventBus.addListener(plugin);
+		return plugin;
 	}
 }

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

@@ -2,19 +2,23 @@ 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.keyagreement.KeyAgreementListener;
+import org.briarproject.bramble.api.event.Event;
+import org.briarproject.bramble.api.event.EventListener;
+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;
+import org.briarproject.bramble.api.plugin.DiscoveryHandler;
 import org.briarproject.bramble.api.plugin.PluginCallback;
 import org.briarproject.bramble.api.plugin.duplex.DuplexPlugin;
 import org.briarproject.bramble.api.plugin.duplex.DuplexTransportConnection;
 import org.briarproject.bramble.api.properties.TransportProperties;
 import org.briarproject.bramble.api.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;
@@ -35,19 +39,26 @@ 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());
 
@@ -60,9 +71,7 @@ abstract class TcpPlugin implements DuplexPlugin {
 	protected final int maxLatency, maxIdleTime;
 	protected final int connectionTimeout, socketTimeout;
 	protected final AtomicBoolean used = new AtomicBoolean(false);
-
-	protected volatile boolean running = false;
-	protected volatile ServerSocket socket = null;
+	protected final PluginState state = new PluginState();
 
 	/**
 	 * Returns zero or more socket addresses on which the plugin should listen,
@@ -118,14 +127,14 @@ 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, false));
 		bind();
 	}
 
 	protected void bind() {
 		bindExecutor.execute(() -> {
-			if (!running) return;
-			if (socket != null && !socket.isClosed()) return;
+			if (getState() != INACTIVE) return;
 			ServerSocket ss = null;
 			for (InetSocketAddress addr : getLocalSocketAddresses()) {
 				try {
@@ -135,34 +144,28 @@ abstract class TcpPlugin implements DuplexPlugin {
 				} 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()) {
+			if (ss == null) {
 				LOG.info("Could not bind server socket");
 				return;
 			}
-			if (!running) {
-				tryToClose(ss);
+			if (!state.setServerSocket(ss)) {
+				LOG.info("Closing redundant server socket");
+				tryToClose(ss, LOG, WARNING);
 				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();
+			acceptContactConnections(ss);
 		});
 	}
 
-	protected void tryToClose(@Nullable ServerSocket ss) {
-		IoUtils.tryToClose(ss, LOG, WARNING);
-		callback.transportDisabled();
-	}
-
 	String getIpPortString(InetSocketAddress a) {
 		String addr = a.getAddress().getHostAddress();
 		int percent = addr.indexOf('%');
@@ -170,15 +173,16 @@ abstract class TcpPlugin implements DuplexPlugin {
 		return addr + ":" + a.getPort();
 	}
 
-	private void acceptContactConnections() {
-		while (isRunning()) {
+	private void acceptContactConnections(ServerSocket ss) {
+		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
-				if (LOG.isLoggable(INFO)) LOG.info(e.toString());
+				// This is expected when the server socket is closed
+				LOG.info("Server socket closed");
+				state.clearServerSocket(ss);
 				return;
 			}
 			if (LOG.isLoggable(INFO))
@@ -191,13 +195,18 @@ abstract class TcpPlugin implements DuplexPlugin {
 
 	@Override
 	public void stop() {
-		running = false;
-		tryToClose(socket);
+		ServerSocket ss = state.setStopped();
+		tryToClose(ss, LOG, WARNING);
 	}
 
 	@Override
-	public boolean isRunning() {
-		return running && socket != null && !socket.isClosed();
+	public State getState() {
+		return state.getState();
+	}
+
+	@Override
+	public int getReasonsDisabled() {
+		return state.getReasonsDisabled();
 	}
 
 	@Override
@@ -211,9 +220,9 @@ abstract class TcpPlugin implements DuplexPlugin {
 	}
 
 	@Override
-	public void poll(Collection<Pair<TransportProperties, ConnectionHandler>>
-			properties) {
-		if (!isRunning()) return;
+	public void poll(
+			List<Pair<TransportProperties, ConnectionHandler>> properties) {
+		if (getState() != ACTIVE) return;
 		backoff.increment();
 		for (Pair<TransportProperties, ConnectionHandler> p : properties) {
 			connect(p.getFirst(), p.getSecond());
@@ -232,8 +241,8 @@ abstract class TcpPlugin implements DuplexPlugin {
 
 	@Override
 	public DuplexTransportConnection createConnection(TransportProperties p) {
-		if (!isRunning()) return null;
-		ServerSocket ss = socket;
+		ServerSocket ss = state.getServerSocket();
+		if (ss == null) return null;
 		InterfaceAddress local = getLocalInterfaceAddress(ss.getInetAddress());
 		if (local == null) {
 			LOG.warning("No interface for server socket");
@@ -313,22 +322,6 @@ abstract class TcpPlugin implements DuplexPlugin {
 		}
 	}
 
-	@Override
-	public boolean supportsKeyAgreement() {
-		return false;
-	}
-
-	@Override
-	public KeyAgreementListener createKeyAgreementListener(byte[] commitment) {
-		throw new UnsupportedOperationException();
-	}
-
-	@Override
-	public DuplexTransportConnection createKeyAgreementConnection(
-			byte[] commitment, BdfList descriptor) {
-		throw new UnsupportedOperationException();
-	}
-
 	@Override
 	public boolean supportsRendezvous() {
 		return false;
@@ -340,6 +333,17 @@ abstract class TcpPlugin implements DuplexPlugin {
 		throw new UnsupportedOperationException();
 	}
 
+	@Override
+	public boolean supportsDiscovery() {
+		return false;
+	}
+
+	@Override
+	public void discoverPeers(
+			List<Pair<TransportProperties, DiscoveryHandler>> properties) {
+		throw new UnsupportedOperationException();
+	}
+
 	List<InterfaceAddress> getLocalInterfaceAddresses() {
 		List<InterfaceAddress> addrs = new ArrayList<>();
 		for (NetworkInterface iface : getNetworkInterfaces()) {
@@ -366,4 +370,93 @@ 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, false);
+		ServerSocket ss = state.setEnabledByUser(enabledByUser);
+		State s = getState();
+		if (ss != null) {
+			LOG.info("Disabled by user, closing server socket");
+			tryToClose(ss, LOG, WARNING);
+		} else if (s == INACTIVE) {
+			LOG.info("Enabled by user, opening server socket");
+			bind();
+		}
+	}
+
+	@ThreadSafe
+	@NotNullByDefault
+	protected class PluginState {
+
+		@GuardedBy("this")
+		private boolean started = false, stopped = false, enabledByUser = false;
+
+		@GuardedBy("this")
+		@Nullable
+		private ServerSocket serverSocket = null;
+
+		synchronized void setStarted(boolean enabledByUser) {
+			started = true;
+			this.enabledByUser = enabledByUser;
+			callback.pluginStateChanged(getState());
+		}
+
+		@Nullable
+		synchronized ServerSocket setStopped() {
+			stopped = true;
+			ServerSocket ss = serverSocket;
+			serverSocket = null;
+			callback.pluginStateChanged(getState());
+			return ss;
+		}
+
+		@Nullable
+		synchronized ServerSocket setEnabledByUser(boolean enabledByUser) {
+			this.enabledByUser = enabledByUser;
+			ServerSocket ss = null;
+			if (!enabledByUser) {
+				ss = serverSocket;
+				serverSocket = null;
+			}
+			callback.pluginStateChanged(getState());
+			return ss;
+		}
+
+		@Nullable
+		synchronized ServerSocket getServerSocket() {
+			return serverSocket;
+		}
+
+		synchronized boolean setServerSocket(ServerSocket ss) {
+			if (stopped || serverSocket != null) return false;
+			serverSocket = ss;
+			callback.pluginStateChanged(getState());
+			return true;
+		}
+
+		synchronized void clearServerSocket(ServerSocket ss) {
+			if (serverSocket == ss) serverSocket = null;
+			callback.pluginStateChanged(getState());
+		}
+
+		synchronized State getState() {
+			if (!started || stopped) 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/tcp/WanTcpPlugin.java

@@ -1,10 +1,13 @@
 package org.briarproject.bramble.plugin.tcp;
 
+import org.briarproject.bramble.api.data.BdfList;
+import org.briarproject.bramble.api.keyagreement.KeyAgreementListener;
 import org.briarproject.bramble.api.nullsafety.MethodsNotNullByDefault;
 import org.briarproject.bramble.api.nullsafety.ParametersNotNullByDefault;
 import org.briarproject.bramble.api.plugin.Backoff;
 import org.briarproject.bramble.api.plugin.PluginCallback;
 import org.briarproject.bramble.api.plugin.TransportId;
+import org.briarproject.bramble.api.plugin.duplex.DuplexTransportConnection;
 import org.briarproject.bramble.api.properties.TransportProperties;
 
 import java.net.Inet4Address;
@@ -42,6 +45,22 @@ class WanTcpPlugin extends TcpPlugin {
 		return ID;
 	}
 
+	@Override
+	public boolean supportsKeyAgreement() {
+		return false;
+	}
+
+	@Override
+	public KeyAgreementListener createKeyAgreementListener(byte[] commitment) {
+		throw new UnsupportedOperationException();
+	}
+
+	@Override
+	public DuplexTransportConnection createKeyAgreementConnection(
+			byte[] commitment, BdfList descriptor) {
+		throw new UnsupportedOperationException();
+	}
+
 	@Override
 	protected List<InetSocketAddress> getLocalSocketAddresses() {
 		// Use the same address and port as last time if available

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

@@ -1,5 +1,6 @@
 package org.briarproject.bramble.plugin.tcp;
 
+import org.briarproject.bramble.api.event.EventBus;
 import org.briarproject.bramble.api.lifecycle.ShutdownManager;
 import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
 import org.briarproject.bramble.api.plugin.Backoff;
@@ -27,12 +28,14 @@ public class WanTcpPluginFactory implements DuplexPluginFactory {
 	private static final double BACKOFF_BASE = 1.2;
 
 	private final Executor ioExecutor;
+	private final EventBus eventBus;
 	private final BackoffFactory backoffFactory;
 	private final ShutdownManager shutdownManager;
 
-	public WanTcpPluginFactory(Executor ioExecutor,
+	public WanTcpPluginFactory(Executor ioExecutor, EventBus eventBus,
 			BackoffFactory backoffFactory, ShutdownManager shutdownManager) {
 		this.ioExecutor = ioExecutor;
+		this.eventBus = eventBus;
 		this.backoffFactory = backoffFactory;
 		this.shutdownManager = shutdownManager;
 	}
@@ -51,8 +54,10 @@ 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,
+		WanTcpPlugin plugin = new WanTcpPlugin(ioExecutor, backoff,
 				new PortMapperImpl(shutdownManager), 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

@@ -15,9 +15,11 @@ 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;
+import org.briarproject.bramble.api.plugin.DiscoveryHandler;
 import org.briarproject.bramble.api.plugin.PluginCallback;
 import org.briarproject.bramble.api.plugin.PluginException;
 import org.briarproject.bramble.api.plugin.TorConstants;
@@ -54,6 +56,9 @@ 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;
@@ -65,6 +70,11 @@ 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.ID;
 import static org.briarproject.bramble.api.plugin.TorConstants.PREF_TOR_MOBILE;
@@ -76,6 +86,9 @@ import static org.briarproject.bramble.api.plugin.TorConstants.PREF_TOR_ONLY_WHE
 import static org.briarproject.bramble.api.plugin.TorConstants.PREF_TOR_PORT;
 import static org.briarproject.bramble.api.plugin.TorConstants.PROP_ONION_V2;
 import static org.briarproject.bramble.api.plugin.TorConstants.PROP_ONION_V3;
+import static org.briarproject.bramble.api.plugin.TorConstants.REASON_BATTERY;
+import static org.briarproject.bramble.api.plugin.TorConstants.REASON_COUNTRY_BLOCKED;
+import static org.briarproject.bramble.api.plugin.TorConstants.REASON_MOBILE_DATA;
 import static org.briarproject.bramble.plugin.tor.TorRendezvousCrypto.SEED_BYTES;
 import static org.briarproject.bramble.util.IoUtils.copyAndClose;
 import static org.briarproject.bramble.util.IoUtils.tryToClose;
@@ -113,16 +126,14 @@ 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();
@@ -159,7 +170,6 @@ 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 +200,7 @@ 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 +268,6 @@ 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 +275,12 @@ 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 +288,18 @@ abstract class TorPlugin implements DuplexPlugin, EventHandler, EventListener {
 		bind();
 	}
 
+	// TODO: Remove after a reasonable migration period (added 2020-01-16)
+	private Settings migrateSettings(Settings settings) {
+		int network = settings.getInt(PREF_TOR_NETWORK,
+				PREF_TOR_NETWORK_AUTOMATIC);
+		if (network == PREF_TOR_NETWORK_NEVER) {
+			settings.putInt(PREF_TOR_NETWORK, PREF_TOR_NETWORK_AUTOMATIC);
+			settings.putBoolean(PREF_PLUGIN_ENABLE, false);
+			callback.mergeSettings(settings);
+		}
+		return settings;
+	}
+
 	private boolean assetsAreUpToDate() {
 		return doneFile.lastModified() > getLastUpdateTime();
 	}
@@ -393,11 +415,11 @@ 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();
@@ -412,7 +434,7 @@ abstract class TorPlugin implements DuplexPlugin, EventHandler, EventListener {
 	}
 
 	private void publishHiddenService(String port) {
-		if (!running) return;
+		if (!state.isTorRunning()) return;
 		LOG.info("Creating hidden service");
 		String privKey = settings.get(HS_PRIVKEY);
 		Map<Integer, String> portLines = singletonMap(80, "127.0.0.1:" + port);
@@ -450,14 +472,15 @@ abstract class TorPlugin implements DuplexPlugin, EventHandler, EventListener {
 	}
 
 	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
-				if (LOG.isLoggable(INFO)) LOG.info(e.toString());
+				// This is expected when the server socket is closed
+				LOG.info("Server socket closed");
+				state.clearServerSocket(ss);
 				return;
 			}
 			LOG.info("Connection received");
@@ -467,10 +490,8 @@ abstract class TorPlugin implements DuplexPlugin, EventHandler, EventListener {
 	}
 
 	protected void enableNetwork(boolean enable) throws IOException {
-		if (!running) return;
-		connectionStatus.enableNetwork(enable);
+		state.enableNetwork(enable);
 		controlConnection.setConf("DisableNetwork", enable ? "0" : "1");
-		if (!enable) callback.transportDisabled();
 	}
 
 	private void enableBridges(boolean enable, boolean needsMeek)
@@ -494,9 +515,8 @@ abstract class TorPlugin implements DuplexPlugin, EventHandler, EventListener {
 
 	@Override
 	public void stop() {
-		running = false;
-		tryToClose(socket, LOG, WARNING);
-		callback.transportDisabled();
+		ServerSocket ss = state.setStopped();
+		tryToClose(ss, LOG, WARNING);
 		if (controlSocket != null && controlConnection != null) {
 			try {
 				LOG.info("Stopping Tor");
@@ -510,8 +530,13 @@ abstract class TorPlugin implements DuplexPlugin, EventHandler, EventListener {
 	}
 
 	@Override
-	public boolean isRunning() {
-		return running && connectionStatus.isConnected();
+	public State getState() {
+		return state.getState();
+	}
+
+	@Override
+	public int getReasonsDisabled() {
+		return state.getReasonsDisabled();
 	}
 
 	@Override
@@ -525,9 +550,9 @@ abstract class TorPlugin implements DuplexPlugin, EventHandler, EventListener {
 	}
 
 	@Override
-	public void poll(Collection<Pair<TransportProperties, ConnectionHandler>>
-			properties) {
-		if (!isRunning()) return;
+	public void poll(
+			List<Pair<TransportProperties, ConnectionHandler>> properties) {
+		if (getState() != ACTIVE) return;
 		backoff.increment();
 		for (Pair<TransportProperties, ConnectionHandler> p : properties) {
 			connect(p.getFirst(), p.getSecond());
@@ -546,7 +571,7 @@ 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;
 		String onion2 = p.get(PROP_ONION_V2);
 		String onion3 = p.get(PROP_ONION_V3);
@@ -634,8 +659,8 @@ abstract class TorPlugin implements DuplexPlugin, EventHandler, EventListener {
 								new TorTransportConnection(this, s));
 					}
 				} catch (IOException e) {
-					// This is expected when the socket is closed
-					if (LOG.isLoggable(INFO)) LOG.info(e.toString());
+					// This is expected when the server socket is closed
+					LOG.info("Rendezvous server socket closed");
 				}
 			});
 			Map<Integer, String> portLines =
@@ -660,13 +685,23 @@ abstract class TorPlugin implements DuplexPlugin, EventHandler, EventListener {
 		}
 	}
 
+	@Override
+	public boolean supportsDiscovery() {
+		return false;
+	}
+
+	@Override
+	public void discoverPeers(
+			List<Pair<TransportProperties, DiscoveryHandler>> properties) {
+		throw new UnsupportedOperationException();
+	}
+
 	@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();
 		}
 	}
 
@@ -697,9 +732,8 @@ 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();
 		}
 	}
 
@@ -736,7 +770,7 @@ 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);
 			}
@@ -746,12 +780,14 @@ 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, true);
 			int network = settings.getInt(PREF_TOR_NETWORK,
 					PREF_TOR_NETWORK_AUTOMATIC);
 			boolean useMobile = settings.getBoolean(PREF_TOR_MOBILE, true);
@@ -762,47 +798,70 @@ abstract class TorPlugin implements DuplexPlugin, EventHandler, EventListener {
 
 			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 {
-				if (!online) {
-					LOG.info("Disabling network, device is offline");
-					enableNetwork(false);
-				} else if (!charging && onlyWhenCharging) {
-					LOG.info("Disabling network, device is on battery");
-					enableNetwork(false);
-				} else if (network == PREF_TOR_NETWORK_NEVER ||
-						(!useMobile && !wifi)) {
-					LOG.info("Disabling network, device is using mobile data");
-					enableNetwork(false);
-				} else if (automatic && blocked && !bridgesWork) {
-					LOG.info("Disabling network, country is blocked");
-					enableNetwork(false);
-				} else if (network == PREF_TOR_NETWORK_WITH_BRIDGES ||
-						(automatic && bridgesWork)) {
-					if (circumventionProvider.needsMeek(country)) {
-						LOG.info("Enabling network, using meek bridges");
-						enableBridges(true, true);
+			int reasonsDisabled = 0;
+			boolean enableNetwork = false, enableBridges = false;
+			boolean useMeek = false, enableConnectionPadding = false;
+
+			if (!online) {
+				LOG.info("Disabling network, device is offline");
+			} else {
+				if (!enabledByUser) {
+					LOG.info("User has disabled Tor");
+					reasonsDisabled |= REASON_USER;
+				}
+				if (!charging && onlyWhenCharging) {
+					LOG.info("Configured not to use battery");
+					reasonsDisabled |= REASON_BATTERY;
+				}
+				if (!useMobile && !wifi) {
+					LOG.info("Configured not to use mobile data");
+					reasonsDisabled |= REASON_MOBILE_DATA;
+				}
+				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");
-						enableBridges(true, false);
+						LOG.info("Not using bridges");
+					}
+					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);
-				} else {
-					LOG.info("Disabling connection padding");
-					enableConnectionPadding(false);
+			}
+
+			state.setReasonsDisabled(reasonsDisabled);
+
+			try {
+				if (enableNetwork) {
+					enableBridges(enableBridges, useMeek);
+					enableConnectionPadding(enableConnectionPadding);
 				}
+				enableNetwork(enableNetwork);
 			} catch (IOException e) {
 				logException(LOG, WARNING, e);
 			}
@@ -810,33 +869,96 @@ 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
-		private boolean networkEnabled = false;
-		private boolean bootstrapped = false, circuitBuilt = false;
+		@GuardedBy("this")
+		private boolean started = false,
+				stopped = false,
+				networkInitialised = false,
+				networkEnabled = false,
+				bootstrapped = false,
+				circuitBuilt = false,
+				settingsChecked = false;
 
-		private synchronized void setBootstrapped() {
-			bootstrapped = true;
+		@GuardedBy("this")
+		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() {
-			return networkEnabled && bootstrapped && circuitBuilt;
+		synchronized void setReasonsDisabled(int reasonsDisabled) {
+			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

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

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

@@ -2,7 +2,6 @@ package org.briarproject.bramble.rendezvous;
 
 import org.briarproject.bramble.PoliteExecutor;
 import org.briarproject.bramble.api.Pair;
-import org.briarproject.bramble.api.connection.ConnectionManager;
 import org.briarproject.bramble.api.contact.PendingContact;
 import org.briarproject.bramble.api.contact.PendingContactId;
 import org.briarproject.bramble.api.contact.PendingContactState;
@@ -24,6 +23,7 @@ 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.ConnectionHandler;
+import org.briarproject.bramble.api.plugin.ConnectionManager;
 import org.briarproject.bramble.api.plugin.Plugin;
 import org.briarproject.bramble.api.plugin.PluginManager;
 import org.briarproject.bramble.api.plugin.TransportConnectionReader;
@@ -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.TransportEnabledEvent;
+import org.briarproject.bramble.api.plugin.event.TransportActiveEvent;
+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;
@@ -269,11 +269,11 @@ class RendezvousPollerImpl implements RendezvousPoller, Service, EventListener {
 		} else if (e instanceof PendingContactRemovedEvent) {
 			PendingContactRemovedEvent p = (PendingContactRemovedEvent) e;
 			removePendingContactAsync(p.getId());
-		} else if (e instanceof TransportEnabledEvent) {
-			TransportEnabledEvent t = (TransportEnabledEvent) e;
+		} else if (e instanceof TransportActiveEvent) {
+			TransportActiveEvent t = (TransportActiveEvent) e;
 			addTransportAsync(t.getTransportId());
-		} else if (e instanceof TransportDisabledEvent) {
-			TransportDisabledEvent t = (TransportDisabledEvent) e;
+		} else if (e instanceof TransportInactiveEvent) {
+			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) {
-			TransportEnabledEvent t = (TransportEnabledEvent) e;
+		if (e instanceof TransportActiveEvent) {
+			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

@@ -14,7 +14,6 @@ import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
 import org.briarproject.bramble.api.sync.Ack;
 import org.briarproject.bramble.api.sync.Message;
 import org.briarproject.bramble.api.sync.Offer;
-import org.briarproject.bramble.api.sync.Priority;
 import org.briarproject.bramble.api.sync.Request;
 import org.briarproject.bramble.api.sync.SyncRecordWriter;
 import org.briarproject.bramble.api.sync.SyncSession;
@@ -36,7 +35,6 @@ import java.util.concurrent.atomic.AtomicBoolean;
 import java.util.concurrent.atomic.AtomicLong;
 import java.util.logging.Logger;
 
-import javax.annotation.Nullable;
 import javax.annotation.concurrent.ThreadSafe;
 
 import static java.util.concurrent.TimeUnit.MILLISECONDS;
@@ -76,8 +74,6 @@ class DuplexOutgoingSession implements SyncSession, EventListener {
 	private final int maxLatency, maxIdleTime;
 	private final StreamWriter streamWriter;
 	private final SyncRecordWriter recordWriter;
-	@Nullable
-	private final Priority priority;
 	private final BlockingQueue<ThrowingRunnable<IOException>> writerTasks;
 
 	private final AtomicBoolean generateAckQueued = new AtomicBoolean(false);
@@ -92,7 +88,7 @@ class DuplexOutgoingSession implements SyncSession, EventListener {
 	DuplexOutgoingSession(DatabaseComponent db, Executor dbExecutor,
 			EventBus eventBus, Clock clock, ContactId contactId, int maxLatency,
 			int maxIdleTime, StreamWriter streamWriter,
-			SyncRecordWriter recordWriter, @Nullable Priority priority) {
+			SyncRecordWriter recordWriter) {
 		this.db = db;
 		this.dbExecutor = dbExecutor;
 		this.eventBus = eventBus;
@@ -102,7 +98,6 @@ class DuplexOutgoingSession implements SyncSession, EventListener {
 		this.maxIdleTime = maxIdleTime;
 		this.streamWriter = streamWriter;
 		this.recordWriter = recordWriter;
-		this.priority = priority;
 		writerTasks = new LinkedBlockingQueue<>();
 	}
 
@@ -113,8 +108,6 @@ class DuplexOutgoingSession implements SyncSession, EventListener {
 		try {
 			// Send our supported protocol versions
 			recordWriter.writeVersions(new Versions(SUPPORTED_VERSIONS));
-			// Send our connection priority, if this is an outgoing connection
-			if (priority != null) recordWriter.writePriority(priority);
 			// Start a query for each type of record
 			generateAck();
 			generateBatch();
@@ -166,9 +159,6 @@ class DuplexOutgoingSession implements SyncSession, EventListener {
 						dataToFlush = true;
 					}
 				}
-				// Write any records that were already in the queue
-				ThrowingRunnable<IOException> task;
-				while ((task = writerTasks.poll()) != null) task.run();
 				streamWriter.sendEndOfStream();
 			} catch (InterruptedException e) {
 				LOG.info("Interrupted while waiting for a record to write");

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

@@ -15,8 +15,6 @@ import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
 import org.briarproject.bramble.api.sync.Ack;
 import org.briarproject.bramble.api.sync.Message;
 import org.briarproject.bramble.api.sync.Offer;
-import org.briarproject.bramble.api.sync.Priority;
-import org.briarproject.bramble.api.sync.PriorityHandler;
 import org.briarproject.bramble.api.sync.Request;
 import org.briarproject.bramble.api.sync.SyncRecordReader;
 import org.briarproject.bramble.api.sync.SyncSession;
@@ -49,19 +47,17 @@ class IncomingSession implements SyncSession, EventListener {
 	private final EventBus eventBus;
 	private final ContactId contactId;
 	private final SyncRecordReader recordReader;
-	private final PriorityHandler priorityHandler;
 
 	private volatile boolean interrupted = false;
 
 	IncomingSession(DatabaseComponent db, Executor dbExecutor,
 			EventBus eventBus, ContactId contactId,
-			SyncRecordReader recordReader, PriorityHandler priorityHandler) {
+			SyncRecordReader recordReader) {
 		this.db = db;
 		this.dbExecutor = dbExecutor;
 		this.eventBus = eventBus;
 		this.contactId = contactId;
 		this.recordReader = recordReader;
-		this.priorityHandler = priorityHandler;
 	}
 
 	@IoExecutor
@@ -90,9 +86,6 @@ class IncomingSession implements SyncSession, EventListener {
 				} else if (recordReader.hasVersions()) {
 					Versions v = recordReader.readVersions();
 					dbExecutor.execute(new ReceiveVersions(v));
-				} else if (recordReader.hasPriority()) {
-					Priority p = recordReader.readPriority();
-					priorityHandler.handle(p);
 				} else {
 					// unknown records are ignored in RecordReader#eof()
 					throw new FormatException();

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

@@ -95,9 +95,6 @@ class SimplexOutgoingSession implements SyncSession, EventListener {
 					if (task == CLOSE) break;
 					task.run();
 				}
-				// Write any records that were already in the queue
-				ThrowingRunnable<IOException> task;
-				while ((task = writerTasks.poll()) != null) task.run();
 				streamWriter.sendEndOfStream();
 			} catch (InterruptedException e) {
 				LOG.info("Interrupted while waiting for a record to write");

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

@@ -11,7 +11,6 @@ import org.briarproject.bramble.api.sync.Message;
 import org.briarproject.bramble.api.sync.MessageFactory;
 import org.briarproject.bramble.api.sync.MessageId;
 import org.briarproject.bramble.api.sync.Offer;
-import org.briarproject.bramble.api.sync.Priority;
 import org.briarproject.bramble.api.sync.Request;
 import org.briarproject.bramble.api.sync.SyncRecordReader;
 import org.briarproject.bramble.api.sync.Versions;
@@ -27,12 +26,10 @@ import javax.annotation.concurrent.NotThreadSafe;
 import static org.briarproject.bramble.api.sync.RecordTypes.ACK;
 import static org.briarproject.bramble.api.sync.RecordTypes.MESSAGE;
 import static org.briarproject.bramble.api.sync.RecordTypes.OFFER;
-import static org.briarproject.bramble.api.sync.RecordTypes.PRIORITY;
 import static org.briarproject.bramble.api.sync.RecordTypes.REQUEST;
 import static org.briarproject.bramble.api.sync.RecordTypes.VERSIONS;
 import static org.briarproject.bramble.api.sync.SyncConstants.MAX_SUPPORTED_VERSIONS;
 import static org.briarproject.bramble.api.sync.SyncConstants.MESSAGE_HEADER_LENGTH;
-import static org.briarproject.bramble.api.sync.SyncConstants.PRIORITY_NONCE_BYTES;
 import static org.briarproject.bramble.api.sync.SyncConstants.PROTOCOL_VERSION;
 
 @NotThreadSafe
@@ -51,7 +48,7 @@ class SyncRecordReaderImpl implements SyncRecordReader {
 
 	private static boolean isKnownRecordType(byte type) {
 		return type == ACK || type == MESSAGE || type == OFFER ||
-				type == REQUEST || type == VERSIONS || type == PRIORITY;
+				type == REQUEST || type == VERSIONS;
 	}
 
 	private final MessageFactory messageFactory;
@@ -177,23 +174,4 @@ class SyncRecordReaderImpl implements SyncRecordReader {
 		nextRecord = null;
 		return supported;
 	}
-
-	@Override
-	public boolean hasPriority() throws IOException {
-		return !eof() && getNextRecordType() == PRIORITY;
-	}
-
-	@Override
-	public Priority readPriority() throws IOException {
-		if (!hasPriority()) throw new FormatException();
-		return new Priority(readNonce());
-	}
-
-	private byte[] readNonce() throws IOException {
-		if (nextRecord == null) throw new AssertionError();
-		byte[] payload = nextRecord.getPayload();
-		if (payload.length != PRIORITY_NONCE_BYTES) throw new FormatException();
-		nextRecord = null;
-		return payload;
-	}
 }

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

@@ -8,7 +8,6 @@ import org.briarproject.bramble.api.sync.Message;
 import org.briarproject.bramble.api.sync.MessageFactory;
 import org.briarproject.bramble.api.sync.MessageId;
 import org.briarproject.bramble.api.sync.Offer;
-import org.briarproject.bramble.api.sync.Priority;
 import org.briarproject.bramble.api.sync.Request;
 import org.briarproject.bramble.api.sync.SyncRecordWriter;
 import org.briarproject.bramble.api.sync.Versions;
@@ -21,7 +20,6 @@ import javax.annotation.concurrent.NotThreadSafe;
 import static org.briarproject.bramble.api.sync.RecordTypes.ACK;
 import static org.briarproject.bramble.api.sync.RecordTypes.MESSAGE;
 import static org.briarproject.bramble.api.sync.RecordTypes.OFFER;
-import static org.briarproject.bramble.api.sync.RecordTypes.PRIORITY;
 import static org.briarproject.bramble.api.sync.RecordTypes.REQUEST;
 import static org.briarproject.bramble.api.sync.RecordTypes.VERSIONS;
 import static org.briarproject.bramble.api.sync.SyncConstants.PROTOCOL_VERSION;
@@ -75,12 +73,6 @@ class SyncRecordWriterImpl implements SyncRecordWriter {
 		writeRecord(VERSIONS);
 	}
 
-	@Override
-	public void writePriority(Priority p) throws IOException {
-		writer.writeRecord(
-				new Record(PROTOCOL_VERSION, PRIORITY, p.getNonce()));
-	}
-
 	@Override
 	public void flush() throws IOException {
 		writer.flush();

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

@@ -5,8 +5,6 @@ import org.briarproject.bramble.api.db.DatabaseComponent;
 import org.briarproject.bramble.api.db.DatabaseExecutor;
 import org.briarproject.bramble.api.event.EventBus;
 import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
-import org.briarproject.bramble.api.sync.Priority;
-import org.briarproject.bramble.api.sync.PriorityHandler;
 import org.briarproject.bramble.api.sync.SyncRecordReader;
 import org.briarproject.bramble.api.sync.SyncRecordReaderFactory;
 import org.briarproject.bramble.api.sync.SyncRecordWriter;
@@ -20,7 +18,6 @@ import java.io.InputStream;
 import java.io.OutputStream;
 import java.util.concurrent.Executor;
 
-import javax.annotation.Nullable;
 import javax.annotation.concurrent.Immutable;
 import javax.inject.Inject;
 
@@ -49,12 +46,10 @@ class SyncSessionFactoryImpl implements SyncSessionFactory {
 	}
 
 	@Override
-	public SyncSession createIncomingSession(ContactId c, InputStream in,
-			PriorityHandler handler) {
+	public SyncSession createIncomingSession(ContactId c, InputStream in) {
 		SyncRecordReader recordReader =
 				recordReaderFactory.createRecordReader(in);
-		return new IncomingSession(db, dbExecutor, eventBus, c, recordReader,
-				handler);
+		return new IncomingSession(db, dbExecutor, eventBus, c, recordReader);
 	}
 
 	@Override
@@ -69,12 +64,11 @@ class SyncSessionFactoryImpl implements SyncSessionFactory {
 
 	@Override
 	public SyncSession createDuplexOutgoingSession(ContactId c, int maxLatency,
-			int maxIdleTime, StreamWriter streamWriter,
-			@Nullable Priority priority) {
+			int maxIdleTime, StreamWriter streamWriter) {
 		OutputStream out = streamWriter.getOutputStream();
 		SyncRecordWriter recordWriter =
 				recordWriterFactory.createRecordWriter(out);
 		return new DuplexOutgoingSession(db, dbExecutor, eventBus, clock, c,
-				maxLatency, maxIdleTime, streamWriter, recordWriter, priority);
+				maxLatency, maxIdleTime, streamWriter, recordWriter);
 	}
 }

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

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

bramble-core/src/test/java/org/briarproject/bramble/connection/ConnectionRegistryImplTest.java

@@ -1,600 +0,0 @@
-package org.briarproject.bramble.connection;
-
-import org.briarproject.bramble.api.connection.ConnectionRegistry;
-import org.briarproject.bramble.api.connection.InterruptibleConnection;
-import org.briarproject.bramble.api.contact.ContactId;
-import org.briarproject.bramble.api.contact.PendingContactId;
-import org.briarproject.bramble.api.event.EventBus;
-import org.briarproject.bramble.api.plugin.PluginConfig;
-import org.briarproject.bramble.api.plugin.TransportId;
-import org.briarproject.bramble.api.plugin.event.ConnectionClosedEvent;
-import org.briarproject.bramble.api.plugin.event.ConnectionOpenedEvent;
-import org.briarproject.bramble.api.plugin.event.ContactConnectedEvent;
-import org.briarproject.bramble.api.plugin.event.ContactDisconnectedEvent;
-import org.briarproject.bramble.api.rendezvous.event.RendezvousConnectionClosedEvent;
-import org.briarproject.bramble.api.rendezvous.event.RendezvousConnectionOpenedEvent;
-import org.briarproject.bramble.api.sync.Priority;
-import org.briarproject.bramble.test.BrambleMockTestCase;
-import org.jmock.Expectations;
-import org.junit.Test;
-
-import java.util.Collection;
-
-import static java.util.Collections.emptyList;
-import static java.util.Collections.emptyMap;
-import static java.util.Collections.singletonList;
-import static java.util.Collections.singletonMap;
-import static org.briarproject.bramble.test.TestUtils.getContactId;
-import static org.briarproject.bramble.test.TestUtils.getRandomId;
-import static org.briarproject.bramble.test.TestUtils.getTransportId;
-import static org.briarproject.bramble.util.StringUtils.fromHexString;
-import static org.junit.Assert.assertEquals;
-import static org.junit.Assert.assertFalse;
-import static org.junit.Assert.assertTrue;
-import static org.junit.Assert.fail;
-
-public class ConnectionRegistryImplTest extends BrambleMockTestCase {
-
-	private final EventBus eventBus = context.mock(EventBus.class);
-	private final PluginConfig pluginConfig = context.mock(PluginConfig.class);
-	private final InterruptibleConnection conn1 =
-			context.mock(InterruptibleConnection.class, "conn1");
-	private final InterruptibleConnection conn2 =
-			context.mock(InterruptibleConnection.class, "conn2");
-	private final InterruptibleConnection conn3 =
-			context.mock(InterruptibleConnection.class, "conn3");
-
-	private final ContactId contactId1 = getContactId();
-	private final ContactId contactId2 = getContactId();
-	private final TransportId transportId1 = getTransportId();
-	private final TransportId transportId2 = getTransportId();
-	private final TransportId transportId3 = getTransportId();
-	private final PendingContactId pendingContactId =
-			new PendingContactId(getRandomId());
-
-	private final Priority low =
-			new Priority(fromHexString("00000000000000000000000000000000"));
-	private final Priority high =
-			new Priority(fromHexString("FFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFF"));
-
-	@Test
-	public void testRegisterMultipleConnections() {
-		context.checking(new Expectations() {{
-			allowing(pluginConfig).getTransportPreferences();
-			will(returnValue(emptyMap()));
-		}});
-
-		ConnectionRegistry c =
-				new ConnectionRegistryImpl(eventBus, pluginConfig);
-
-		// The registry should be empty
-		assertEquals(emptyList(), c.getConnectedContacts(transportId1));
-		assertEquals(emptyList(), c.getConnectedOrBetterContacts(transportId1));
-		assertEquals(emptyList(), c.getConnectedContacts(transportId2));
-		assertEquals(emptyList(), c.getConnectedOrBetterContacts(transportId2));
-		assertEquals(emptyList(), c.getConnectedContacts(transportId3));
-		assertEquals(emptyList(), c.getConnectedOrBetterContacts(transportId3));
-
-		// Check that a registered connection shows up - this should
-		// broadcast a ConnectionOpenedEvent and a ContactConnectedEvent
-		context.checking(new Expectations() {{
-			oneOf(eventBus).broadcast(with(any(ConnectionOpenedEvent.class)));
-			oneOf(eventBus).broadcast(with(any(ContactConnectedEvent.class)));
-		}});
-		c.registerConnection(contactId1, transportId1, conn1, true);
-		context.assertIsSatisfied();
-
-		assertEquals(singletonList(contactId1),
-				c.getConnectedContacts(transportId1));
-		assertEquals(singletonList(contactId1),
-				c.getConnectedOrBetterContacts(transportId1));
-
-		// Register another connection with the same contact and transport -
-		// this should broadcast a ConnectionOpenedEvent and lookup should be
-		// unaffected
-		context.checking(new Expectations() {{
-			oneOf(eventBus).broadcast(with(any(ConnectionOpenedEvent.class)));
-		}});
-		c.registerConnection(contactId1, transportId1, conn2, true);
-		context.assertIsSatisfied();
-
-		assertEquals(singletonList(contactId1),
-				c.getConnectedContacts(transportId1));
-		assertEquals(singletonList(contactId1),
-				c.getConnectedOrBetterContacts(transportId1));
-
-		// Unregister one of the connections - this should broadcast a
-		// ConnectionClosedEvent and lookup should be unaffected
-		context.checking(new Expectations() {{
-			oneOf(eventBus).broadcast(with(any(ConnectionClosedEvent.class)));
-		}});
-		c.unregisterConnection(contactId1, transportId1, conn1, true, false);
-		context.assertIsSatisfied();
-
-		assertEquals(singletonList(contactId1),
-				c.getConnectedContacts(transportId1));
-		assertEquals(singletonList(contactId1),
-				c.getConnectedOrBetterContacts(transportId1));
-
-		// Unregister the other connection - this should broadcast a
-		// ConnectionClosedEvent and a ContactDisconnectedEvent
-		context.checking(new Expectations() {{
-			oneOf(eventBus).broadcast(with(any(ConnectionClosedEvent.class)));
-			oneOf(eventBus).broadcast(with(any(
-					ContactDisconnectedEvent.class)));
-		}});
-		c.unregisterConnection(contactId1, transportId1, conn2, true, false);
-		context.assertIsSatisfied();
-
-		assertEquals(emptyList(), c.getConnectedContacts(transportId1));
-		assertEquals(emptyList(), c.getConnectedOrBetterContacts(transportId1));
-
-		// Try to unregister the connection again - exception should be thrown
-		try {
-			c.unregisterConnection(contactId1, transportId1, conn2,
-					true, false);
-			fail();
-		} catch (IllegalArgumentException expected) {
-			// Expected
-		}
-	}
-
-	@Test
-	public void testRegisterMultipleContacts() {
-		context.checking(new Expectations() {{
-			allowing(pluginConfig).getTransportPreferences();
-			will(returnValue(emptyMap()));
-		}});
-
-		ConnectionRegistry c =
-				new ConnectionRegistryImpl(eventBus, pluginConfig);
-
-		// Register two contacts with one transport, then one of the contacts
-		// with a second transport - this should broadcast three
-		// ConnectionOpenedEvents and two ContactConnectedEvents
-		context.checking(new Expectations() {{
-			exactly(3).of(eventBus).broadcast(with(any(
-					ConnectionOpenedEvent.class)));
-			exactly(2).of(eventBus).broadcast(with(any(
-					ContactConnectedEvent.class)));
-		}});
-		c.registerConnection(contactId1, transportId1, conn1, true);
-		c.registerConnection(contactId2, transportId1, conn2, true);
-		c.registerConnection(contactId2, transportId2, conn3, true);
-		context.assertIsSatisfied();
-
-		Collection<ContactId> connected = c.getConnectedContacts(transportId1);
-		assertEquals(2, connected.size());
-		assertTrue(connected.contains(contactId1));
-		assertTrue(connected.contains(contactId2));
-
-		connected = c.getConnectedOrBetterContacts(transportId1);
-		assertEquals(2, connected.size());
-		assertTrue(connected.contains(contactId1));
-		assertTrue(connected.contains(contactId2));
-
-		assertEquals(singletonList(contactId2),
-				c.getConnectedContacts(transportId2));
-		assertEquals(singletonList(contactId2),
-				c.getConnectedOrBetterContacts(transportId2));
-	}
-
-	@Test
-	public void testConnectionsAreNotInterruptedUnlessPriorityIsSet() {
-		// Prefer transport 2 to transport 1
-		context.checking(new Expectations() {{
-			allowing(pluginConfig).getTransportPreferences();
-			will(returnValue(
-					singletonMap(transportId1, singletonList(transportId2))));
-		}});
-
-		ConnectionRegistry c =
-				new ConnectionRegistryImpl(eventBus, pluginConfig);
-
-		// Connect via transport 1 (worse than 2) and set priority to low
-		context.checking(new Expectations() {{
-			oneOf(eventBus).broadcast(with(any(ConnectionOpenedEvent.class)));
-			oneOf(eventBus).broadcast(with(any(ContactConnectedEvent.class)));
-		}});
-		c.registerConnection(contactId1, transportId1, conn1, true);
-		context.assertIsSatisfied();
-
-		assertEquals(singletonList(contactId1),
-				c.getConnectedContacts(transportId1));
-		assertEquals(singletonList(contactId1),
-				c.getConnectedOrBetterContacts(transportId1));
-
-		assertEquals(emptyList(), c.getConnectedContacts(transportId2));
-		assertEquals(emptyList(), c.getConnectedOrBetterContacts(transportId2));
-
-		// Connect via transport 2 (better than 1) and set priority to high -
-		// the old connection should not be interrupted, despite using a worse
-		// transport, to remain compatible with old peers
-		context.checking(new Expectations() {{
-			oneOf(eventBus).broadcast(with(any(ConnectionOpenedEvent.class)));
-		}});
-		c.registerConnection(contactId1, transportId2, conn2, true);
-		c.setPriority(contactId1, transportId2, conn2, high);
-		context.assertIsSatisfied();
-
-		assertEquals(singletonList(contactId1),
-				c.getConnectedContacts(transportId1));
-		assertEquals(singletonList(contactId1),
-				c.getConnectedOrBetterContacts(transportId1));
-
-		assertEquals(singletonList(contactId1),
-				c.getConnectedContacts(transportId2));
-		assertEquals(singletonList(contactId1),
-				c.getConnectedOrBetterContacts(transportId2));
-
-		// Connect via transport 3 (no preference) and set priority to high -
-		// again, no interruptions are expected
-		context.checking(new Expectations() {{
-			oneOf(eventBus).broadcast(with(any(ConnectionOpenedEvent.class)));
-		}});
-		c.registerConnection(contactId1, transportId3, conn3, true);
-		c.setPriority(contactId1, transportId3, conn3, high);
-		context.assertIsSatisfied();
-
-		assertEquals(singletonList(contactId1),
-				c.getConnectedContacts(transportId1));
-		assertEquals(singletonList(contactId1),
-				c.getConnectedOrBetterContacts(transportId1));
-
-		assertEquals(singletonList(contactId1),
-				c.getConnectedContacts(transportId2));
-		assertEquals(singletonList(contactId1),
-				c.getConnectedOrBetterContacts(transportId2));
-
-		assertEquals(singletonList(contactId1),
-				c.getConnectedContacts(transportId3));
-		assertEquals(singletonList(contactId1),
-				c.getConnectedOrBetterContacts(transportId3));
-	}
-
-	@Test
-	public void testNewConnectionIsInterruptedIfOldConnectionUsesBetterTransport() {
-		// Prefer transport 1 to transport 2
-		context.checking(new Expectations() {{
-			allowing(pluginConfig).getTransportPreferences();
-			will(returnValue(
-					singletonMap(transportId2, singletonList(transportId1))));
-		}});
-
-		ConnectionRegistry c =
-				new ConnectionRegistryImpl(eventBus, pluginConfig);
-
-		// Connect via transport 1 (better than 2) and set priority to low
-		context.checking(new Expectations() {{
-			oneOf(eventBus).broadcast(with(any(ConnectionOpenedEvent.class)));
-			oneOf(eventBus).broadcast(with(any(ContactConnectedEvent.class)));
-		}});
-		c.registerConnection(contactId1, transportId1, conn1, true);
-		c.setPriority(contactId1, transportId1, conn1, low);
-		context.assertIsSatisfied();
-
-		assertEquals(singletonList(contactId1),
-				c.getConnectedContacts(transportId1));
-		assertEquals(singletonList(contactId1),
-				c.getConnectedOrBetterContacts(transportId1));
-
-		// The contact is not connected via transport 2 but is connected via a
-		// better transport
-		assertEquals(emptyList(), c.getConnectedContacts(transportId2));
-		assertEquals(singletonList(contactId1),
-				c.getConnectedOrBetterContacts(transportId2));
-
-		// Connect via transport 2 (worse than 1) and set priority to high -
-		// the new connection should be interrupted because it uses a worse
-		// transport
-		context.checking(new Expectations() {{
-			oneOf(conn2).interruptOutgoingSession();
-			oneOf(eventBus).broadcast(with(any(ConnectionOpenedEvent.class)));
-		}});
-		c.registerConnection(contactId1, transportId2, conn2, true);
-		c.setPriority(contactId1, transportId2, conn2, high);
-		context.assertIsSatisfied();
-
-		assertEquals(singletonList(contactId1),
-				c.getConnectedContacts(transportId1));
-		assertEquals(singletonList(contactId1),
-				c.getConnectedOrBetterContacts(transportId1));
-
-		assertEquals(singletonList(contactId1),
-				c.getConnectedContacts(transportId2));
-		assertEquals(singletonList(contactId1),
-				c.getConnectedOrBetterContacts(transportId2));
-
-		// Connect via transport 3 (no preference) and set priority to low -
-		// no further interruptions
-		context.checking(new Expectations() {{
-			oneOf(eventBus).broadcast(with(any(ConnectionOpenedEvent.class)));
-		}});
-		c.registerConnection(contactId1, transportId3, conn3, true);
-		c.setPriority(contactId1, transportId3, conn3, low);
-		context.assertIsSatisfied();
-
-		assertEquals(singletonList(contactId1),
-				c.getConnectedContacts(transportId1));
-		assertEquals(singletonList(contactId1),
-				c.getConnectedOrBetterContacts(transportId1));
-
-		assertEquals(singletonList(contactId1),
-				c.getConnectedContacts(transportId2));
-		assertEquals(singletonList(contactId1),
-				c.getConnectedOrBetterContacts(transportId2));
-
-		assertEquals(singletonList(contactId1),
-				c.getConnectedContacts(transportId3));
-		assertEquals(singletonList(contactId1),
-				c.getConnectedOrBetterContacts(transportId3));
-
-		// Unregister the interrupted connection (transport 2)
-		context.checking(new Expectations() {{
-			oneOf(eventBus).broadcast(with(any(ConnectionClosedEvent.class)));
-		}});
-		c.unregisterConnection(contactId1, transportId2, conn2, true, false);
-		context.assertIsSatisfied();
-
-		assertEquals(singletonList(contactId1),
-				c.getConnectedContacts(transportId1));
-		assertEquals(singletonList(contactId1),
-				c.getConnectedOrBetterContacts(transportId1));
-
-		// The contact is not connected via transport 2 but is connected via a
-		// better transport
-		assertEquals(emptyList(), c.getConnectedContacts(transportId2));
-		assertEquals(singletonList(contactId1),
-				c.getConnectedOrBetterContacts(transportId2));
-
-		assertEquals(singletonList(contactId1),
-				c.getConnectedContacts(transportId3));
-		assertEquals(singletonList(contactId1),
-				c.getConnectedOrBetterContacts(transportId3));
-	}
-
-	@Test
-	public void testOldConnectionIsInterruptedIfNewConnectionUsesBetterTransport() {
-		// Prefer transport 2 to transport 1
-		context.checking(new Expectations() {{
-			allowing(pluginConfig).getTransportPreferences();
-			will(returnValue(
-					singletonMap(transportId1, singletonList(transportId2))));
-		}});
-
-		ConnectionRegistry c =
-				new ConnectionRegistryImpl(eventBus, pluginConfig);
-
-		// Connect via transport 1 (worse than 2) and set priority to high
-		context.checking(new Expectations() {{
-			oneOf(eventBus).broadcast(with(any(ConnectionOpenedEvent.class)));
-			oneOf(eventBus).broadcast(with(any(ContactConnectedEvent.class)));
-		}});
-		c.registerConnection(contactId1, transportId1, conn1, true);
-		c.setPriority(contactId1, transportId1, conn1, high);
-		context.assertIsSatisfied();
-
-		assertEquals(singletonList(contactId1),
-				c.getConnectedContacts(transportId1));
-		assertEquals(singletonList(contactId1),
-				c.getConnectedOrBetterContacts(transportId1));
-
-		assertEquals(emptyList(), c.getConnectedContacts(transportId2));
-		assertEquals(emptyList(), c.getConnectedOrBetterContacts(transportId2));
-
-		// Connect via transport 2 (better than 1) and set priority to low -
-		// the old connection should be interrupted because it uses a worse
-		// transport
-		context.checking(new Expectations() {{
-			oneOf(conn1).interruptOutgoingSession();
-			oneOf(eventBus).broadcast(with(any(ConnectionOpenedEvent.class)));
-		}});
-		c.registerConnection(contactId1, transportId2, conn2, true);
-		c.setPriority(contactId1, transportId2, conn2, low);
-		context.assertIsSatisfied();
-
-		assertEquals(singletonList(contactId1),
-				c.getConnectedContacts(transportId1));
-		assertEquals(singletonList(contactId1),
-				c.getConnectedOrBetterContacts(transportId1));
-
-		assertEquals(singletonList(contactId1),
-				c.getConnectedContacts(transportId2));
-		assertEquals(singletonList(contactId1),
-				c.getConnectedOrBetterContacts(transportId2));
-
-		// Connect via transport 3 (no preference) and set priority to high -
-		// no further interruptions
-		context.checking(new Expectations() {{
-			oneOf(eventBus).broadcast(with(any(ConnectionOpenedEvent.class)));
-		}});
-		c.registerConnection(contactId1, transportId3, conn3, true);
-		context.assertIsSatisfied();
-
-		assertEquals(singletonList(contactId1),
-				c.getConnectedContacts(transportId1));
-		assertEquals(singletonList(contactId1),
-				c.getConnectedOrBetterContacts(transportId1));
-
-		assertEquals(singletonList(contactId1),
-				c.getConnectedContacts(transportId2));
-		assertEquals(singletonList(contactId1),
-				c.getConnectedOrBetterContacts(transportId2));
-
-		assertEquals(singletonList(contactId1),
-				c.getConnectedContacts(transportId3));
-		assertEquals(singletonList(contactId1),
-				c.getConnectedOrBetterContacts(transportId3));
-
-		// Unregister the interrupted connection (transport 1)
-		context.checking(new Expectations() {{
-			oneOf(eventBus).broadcast(with(any(ConnectionClosedEvent.class)));
-		}});
-		c.unregisterConnection(contactId1, transportId1, conn1, true, false);
-		context.assertIsSatisfied();
-
-		// The contact is not connected via transport 1 but is connected via a
-		// better transport
-		assertEquals(emptyList(), c.getConnectedContacts(transportId1));
-		assertEquals(singletonList(contactId1),
-				c.getConnectedOrBetterContacts(transportId1));
-
-		assertEquals(singletonList(contactId1),
-				c.getConnectedContacts(transportId2));
-		assertEquals(singletonList(contactId1),
-				c.getConnectedOrBetterContacts(transportId2));
-
-		assertEquals(singletonList(contactId1),
-				c.getConnectedContacts(transportId3));
-		assertEquals(singletonList(contactId1),
-				c.getConnectedOrBetterContacts(transportId3));
-	}
-
-	@Test
-	public void testNewConnectionIsInterruptedIfOldConnectionHasHigherPriority() {
-		context.checking(new Expectations() {{
-			allowing(pluginConfig).getTransportPreferences();
-			will(returnValue(emptyMap()));
-		}});
-
-		ConnectionRegistry c =
-				new ConnectionRegistryImpl(eventBus, pluginConfig);
-
-		// Register a connection with high priority
-		context.checking(new Expectations() {{
-			oneOf(eventBus).broadcast(with(any(ConnectionOpenedEvent.class)));
-			oneOf(eventBus).broadcast(with(any(ContactConnectedEvent.class)));
-		}});
-		c.registerConnection(contactId1, transportId1, conn1, true);
-		c.setPriority(contactId1, transportId1, conn1, high);
-		context.assertIsSatisfied();
-
-		assertEquals(singletonList(contactId1),
-				c.getConnectedContacts(transportId1));
-		assertEquals(singletonList(contactId1),
-				c.getConnectedOrBetterContacts(transportId1));
-
-		// Register another connection via the same transport (no priority yet)
-		context.checking(new Expectations() {{
-			oneOf(eventBus).broadcast(with(any(ConnectionOpenedEvent.class)));
-		}});
-		c.registerConnection(contactId1, transportId1, conn2, true);
-		context.assertIsSatisfied();
-
-		assertEquals(singletonList(contactId1),
-				c.getConnectedContacts(transportId1));
-		assertEquals(singletonList(contactId1),
-				c.getConnectedOrBetterContacts(transportId1));
-
-		// Set the priority of the second connection to low - the second
-		// connection should be interrupted
-		context.checking(new Expectations() {{
-			oneOf(conn2).interruptOutgoingSession();
-		}});
-		c.setPriority(contactId1, transportId1, conn2, low);
-		context.assertIsSatisfied();
-
-		assertEquals(singletonList(contactId1),
-				c.getConnectedContacts(transportId1));
-		assertEquals(singletonList(contactId1),
-				c.getConnectedOrBetterContacts(transportId1));
-
-		// Register a third connection with low priority - it should also be
-		// interrupted
-		context.checking(new Expectations() {{
-			oneOf(conn3).interruptOutgoingSession();
-			oneOf(eventBus).broadcast(with(any(ConnectionOpenedEvent.class)));
-		}});
-		c.registerConnection(contactId1, transportId1, conn3, true);
-		c.setPriority(contactId1, transportId1, conn3, low);
-		context.assertIsSatisfied();
-
-		assertEquals(singletonList(contactId1),
-				c.getConnectedContacts(transportId1));
-		assertEquals(singletonList(contactId1),
-				c.getConnectedOrBetterContacts(transportId1));
-	}
-
-	@Test
-	public void testOldConnectionIsInterruptedIfNewConnectionHasHigherPriority() {
-		context.checking(new Expectations() {{
-			allowing(pluginConfig).getTransportPreferences();
-			will(returnValue(emptyMap()));
-		}});
-
-		ConnectionRegistry c =
-				new ConnectionRegistryImpl(eventBus, pluginConfig);
-
-		// Register a connection with low priority
-		context.checking(new Expectations() {{
-			oneOf(eventBus).broadcast(with(any(ConnectionOpenedEvent.class)));
-			oneOf(eventBus).broadcast(with(any(ContactConnectedEvent.class)));
-		}});
-		c.registerConnection(contactId1, transportId1, conn1, true);
-		c.setPriority(contactId1, transportId1, conn1, low);
-		context.assertIsSatisfied();
-
-		assertEquals(singletonList(contactId1),
-				c.getConnectedContacts(transportId1));
-		assertEquals(singletonList(contactId1),
-				c.getConnectedOrBetterContacts(transportId1));
-
-		// Register another connection via the same transport (no priority yet)
-		context.checking(new Expectations() {{
-			oneOf(eventBus).broadcast(with(any(ConnectionOpenedEvent.class)));
-		}});
-		c.registerConnection(contactId1, transportId1, conn2, true);
-		context.assertIsSatisfied();
-
-		assertEquals(singletonList(contactId1),
-				c.getConnectedContacts(transportId1));
-		assertEquals(singletonList(contactId1),
-				c.getConnectedOrBetterContacts(transportId1));
-
-		// Set the priority of the second connection to high - the first
-		// connection should be interrupted
-		context.checking(new Expectations() {{
-			oneOf(conn1).interruptOutgoingSession();
-		}});
-		c.setPriority(contactId1, transportId1, conn2, high);
-		context.assertIsSatisfied();
-
-		assertEquals(singletonList(contactId1),
-				c.getConnectedContacts(transportId1));
-		assertEquals(singletonList(contactId1),
-				c.getConnectedOrBetterContacts(transportId1));
-	}
-
-	@Test
-	public void testRegisterAndUnregisterPendingContacts() {
-		context.checking(new Expectations() {{
-			allowing(pluginConfig).getTransportPreferences();
-			will(returnValue(emptyMap()));
-		}});
-
-		ConnectionRegistry c =
-				new ConnectionRegistryImpl(eventBus, pluginConfig);
-
-		context.checking(new Expectations() {{
-			oneOf(eventBus).broadcast(with(any(
-					RendezvousConnectionOpenedEvent.class)));
-		}});
-		assertTrue(c.registerConnection(pendingContactId));
-		assertFalse(c.registerConnection(pendingContactId)); // Redundant
-		context.assertIsSatisfied();
-
-		context.checking(new Expectations() {{
-			oneOf(eventBus).broadcast(with(any(
-					RendezvousConnectionClosedEvent.class)));
-		}});
-		c.unregisterConnection(pendingContactId, true);
-		context.assertIsSatisfied();
-
-		try {
-			c.unregisterConnection(pendingContactId, true);
-			fail();
-		} catch (IllegalArgumentException expected) {
-			// Expected
-		}
-	}
-}

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

@@ -2,13 +2,13 @@ package org.briarproject.bramble.contact;
 
 import org.briarproject.bramble.BrambleCoreEagerSingletons;
 import org.briarproject.bramble.BrambleCoreModule;
-import org.briarproject.bramble.api.connection.ConnectionManager;
 import org.briarproject.bramble.api.contact.ContactExchangeManager;
 import org.briarproject.bramble.api.contact.ContactManager;
 import org.briarproject.bramble.api.event.EventBus;
 import org.briarproject.bramble.api.identity.IdentityManager;
 import org.briarproject.bramble.api.lifecycle.IoExecutor;
 import org.briarproject.bramble.api.lifecycle.LifecycleManager;
+import org.briarproject.bramble.api.plugin.ConnectionManager;
 import org.briarproject.bramble.test.BrambleCoreIntegrationTestModule;
 
 import java.util.concurrent.Executor;

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

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

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

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

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

@@ -0,0 +1,149 @@
+package org.briarproject.bramble.plugin;
+
+import org.briarproject.bramble.api.contact.ContactId;
+import org.briarproject.bramble.api.contact.PendingContactId;
+import org.briarproject.bramble.api.event.EventBus;
+import org.briarproject.bramble.api.plugin.ConnectionRegistry;
+import org.briarproject.bramble.api.plugin.TransportId;
+import org.briarproject.bramble.api.plugin.event.ConnectionClosedEvent;
+import org.briarproject.bramble.api.plugin.event.ConnectionOpenedEvent;
+import org.briarproject.bramble.api.plugin.event.ContactConnectedEvent;
+import org.briarproject.bramble.api.plugin.event.ContactDisconnectedEvent;
+import org.briarproject.bramble.api.rendezvous.event.RendezvousConnectionClosedEvent;
+import org.briarproject.bramble.api.rendezvous.event.RendezvousConnectionOpenedEvent;
+import org.briarproject.bramble.test.BrambleMockTestCase;
+import org.jmock.Expectations;
+import org.junit.Test;
+
+import java.util.Collection;
+
+import static java.util.Collections.emptyList;
+import static java.util.Collections.singletonList;
+import static org.briarproject.bramble.test.TestUtils.getContactId;
+import static org.briarproject.bramble.test.TestUtils.getRandomId;
+import static org.briarproject.bramble.test.TestUtils.getTransportId;
+import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertFalse;
+import static org.junit.Assert.assertTrue;
+import static org.junit.Assert.fail;
+
+public class ConnectionRegistryImplTest extends BrambleMockTestCase {
+
+	private final EventBus eventBus = context.mock(EventBus.class);
+
+	private final ContactId contactId = getContactId();
+	private final ContactId contactId1 = getContactId();
+	private final TransportId transportId = getTransportId();
+	private final TransportId transportId1 = getTransportId();
+	private final PendingContactId pendingContactId =
+			new PendingContactId(getRandomId());
+
+	@Test
+	public void testRegisterAndUnregister() {
+		ConnectionRegistry c = new ConnectionRegistryImpl(eventBus);
+
+		// The registry should be empty
+		assertEquals(emptyList(), c.getConnectedContacts(transportId));
+		assertEquals(emptyList(), c.getConnectedContacts(transportId1));
+
+		// Check that a registered connection shows up - this should
+		// broadcast a ConnectionOpenedEvent and a ContactConnectedEvent
+		context.checking(new Expectations() {{
+			oneOf(eventBus).broadcast(with(any(ConnectionOpenedEvent.class)));
+			oneOf(eventBus).broadcast(with(any(ContactConnectedEvent.class)));
+		}});
+		c.registerConnection(contactId, transportId, true);
+		assertEquals(singletonList(contactId),
+				c.getConnectedContacts(transportId));
+		assertEquals(emptyList(), c.getConnectedContacts(transportId1));
+		context.assertIsSatisfied();
+
+		// Register an identical connection - this should broadcast a
+		// ConnectionOpenedEvent and lookup should be unaffected
+		context.checking(new Expectations() {{
+			oneOf(eventBus).broadcast(with(any(ConnectionOpenedEvent.class)));
+		}});
+		c.registerConnection(contactId, transportId, true);
+		assertEquals(singletonList(contactId),
+				c.getConnectedContacts(transportId));
+		assertEquals(emptyList(), c.getConnectedContacts(transportId1));
+		context.assertIsSatisfied();
+
+		// Unregister one of the connections - this should broadcast a
+		// ConnectionClosedEvent and lookup should be unaffected
+		context.checking(new Expectations() {{
+			oneOf(eventBus).broadcast(with(any(ConnectionClosedEvent.class)));
+		}});
+		c.unregisterConnection(contactId, transportId, true);
+		assertEquals(singletonList(contactId),
+				c.getConnectedContacts(transportId));
+		assertEquals(emptyList(), c.getConnectedContacts(transportId1));
+		context.assertIsSatisfied();
+
+		// Unregister the other connection - this should broadcast a
+		// ConnectionClosedEvent and a ContactDisconnectedEvent
+		context.checking(new Expectations() {{
+			oneOf(eventBus).broadcast(with(any(ConnectionClosedEvent.class)));
+			oneOf(eventBus).broadcast(with(any(
+					ContactDisconnectedEvent.class)));
+		}});
+		c.unregisterConnection(contactId, transportId, true);
+		assertEquals(emptyList(), c.getConnectedContacts(transportId));
+		assertEquals(emptyList(), c.getConnectedContacts(transportId1));
+		context.assertIsSatisfied();
+
+		// Try to unregister the connection again - exception should be thrown
+		try {
+			c.unregisterConnection(contactId, transportId, true);
+			fail();
+		} catch (IllegalArgumentException expected) {
+			// Expected
+		}
+
+		// Register both contacts with one transport, one contact with both -
+		// this should broadcast three ConnectionOpenedEvents and two
+		// ContactConnectedEvents
+		context.checking(new Expectations() {{
+			exactly(3).of(eventBus).broadcast(with(any(
+					ConnectionOpenedEvent.class)));
+			exactly(2).of(eventBus).broadcast(with(any(
+					ContactConnectedEvent.class)));
+		}});
+		c.registerConnection(contactId, transportId, true);
+		c.registerConnection(contactId1, transportId, true);
+		c.registerConnection(contactId1, transportId1, true);
+		Collection<ContactId> connected = c.getConnectedContacts(transportId);
+		assertEquals(2, connected.size());
+		assertTrue(connected.contains(contactId));
+		assertTrue(connected.contains(contactId1));
+		assertEquals(singletonList(contactId1),
+				c.getConnectedContacts(transportId1));
+	}
+
+	@Test
+	public void testRegisterAndUnregisterPendingContacts() {
+		ConnectionRegistry c = new ConnectionRegistryImpl(eventBus);
+
+		context.checking(new Expectations() {{
+			oneOf(eventBus).broadcast(with(any(
+					RendezvousConnectionOpenedEvent.class)));
+		}});
+		assertTrue(c.registerConnection(pendingContactId));
+		assertFalse(c.registerConnection(pendingContactId)); // Redundant
+		context.assertIsSatisfied();
+
+		context.checking(new Expectations() {{
+			oneOf(eventBus).broadcast(with(any(
+					RendezvousConnectionClosedEvent.class)));
+		}});
+		c.unregisterConnection(pendingContactId, true);
+		context.assertIsSatisfied();
+
+		try {
+			c.unregisterConnection(pendingContactId, true);
+			fail();
+		} catch (IllegalArgumentException expected) {
+			// Expected
+		}
+	}
+}

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

@@ -1,7 +1,7 @@
 package org.briarproject.bramble.plugin;
 
-import org.briarproject.bramble.api.connection.ConnectionManager;
 import org.briarproject.bramble.api.event.EventBus;
+import org.briarproject.bramble.api.plugin.ConnectionManager;
 import org.briarproject.bramble.api.plugin.PluginCallback;
 import org.briarproject.bramble.api.plugin.PluginConfig;
 import org.briarproject.bramble.api.plugin.PluginException;

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

@@ -1,10 +1,10 @@
 package org.briarproject.bramble.plugin;
 
-import org.briarproject.bramble.api.connection.ConnectionManager;
-import org.briarproject.bramble.api.connection.ConnectionRegistry;
 import org.briarproject.bramble.api.contact.ContactId;
 import org.briarproject.bramble.api.contact.event.ContactAddedEvent;
 import org.briarproject.bramble.api.plugin.ConnectionHandler;
+import org.briarproject.bramble.api.plugin.ConnectionManager;
+import org.briarproject.bramble.api.plugin.ConnectionRegistry;
 import org.briarproject.bramble.api.plugin.Plugin;
 import org.briarproject.bramble.api.plugin.PluginManager;
 import org.briarproject.bramble.api.plugin.TransportConnectionWriter;
@@ -13,8 +13,8 @@ import org.briarproject.bramble.api.plugin.duplex.DuplexPlugin;
 import org.briarproject.bramble.api.plugin.duplex.DuplexTransportConnection;
 import org.briarproject.bramble.api.plugin.event.ConnectionClosedEvent;
 import org.briarproject.bramble.api.plugin.event.ConnectionOpenedEvent;
-import org.briarproject.bramble.api.plugin.event.TransportDisabledEvent;
-import org.briarproject.bramble.api.plugin.event.TransportEnabledEvent;
+import org.briarproject.bramble.api.plugin.event.TransportActiveEvent;
+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;
@@ -38,7 +38,7 @@ import static java.util.Collections.emptyList;
 import static java.util.Collections.singletonList;
 import static java.util.Collections.singletonMap;
 import static java.util.concurrent.TimeUnit.MILLISECONDS;
-import static org.briarproject.bramble.test.CollectionMatcher.collectionOf;
+import static org.briarproject.bramble.test.ListMatcher.listOf;
 import static org.briarproject.bramble.test.PairMatcher.pairOf;
 import static org.briarproject.bramble.test.TestUtils.getContactId;
 import static org.briarproject.bramble.test.TestUtils.getTransportId;
@@ -157,21 +157,7 @@ public class PollerImplTest extends BrambleMockTestCase {
 	}
 
 	@Test
-	public void testRescheduleOnOutgoingConnectionClosed() {
-		DuplexPlugin plugin = context.mock(DuplexPlugin.class);
-
-		context.checking(new Expectations() {{
-			allowing(plugin).getId();
-			will(returnValue(transportId));
-		}});
-		expectReschedule(plugin);
-
-		poller.eventOccurred(new ConnectionClosedEvent(contactId, transportId,
-				false, false));
-	}
-
-	@Test
-	public void testRescheduleAndReconnectOnOutgoingConnectionFailed()
+	public void testRescheduleAndReconnectOnConnectionClosed()
 			throws Exception {
 		DuplexPlugin plugin = context.mock(DuplexPlugin.class);
 		DuplexTransportConnection duplexConnection =
@@ -180,40 +166,45 @@ public class PollerImplTest extends BrambleMockTestCase {
 		context.checking(new Expectations() {{
 			allowing(plugin).getId();
 			will(returnValue(transportId));
+			// reschedule()
+			// Get the plugin
+			oneOf(pluginManager).getPlugin(transportId);
+			will(returnValue(plugin));
+			// The plugin supports polling
+			oneOf(plugin).shouldPoll();
+			will(returnValue(true));
+			// Get the plugin
+			oneOf(pluginManager).getPlugin(transportId);
+			will(returnValue(plugin));
+			// The plugin supports polling
+			oneOf(plugin).shouldPoll();
+			will(returnValue(true));
+			// Schedule the next poll
+			oneOf(plugin).getPollingInterval();
+			will(returnValue(pollingInterval));
+			oneOf(clock).currentTimeMillis();
+			will(returnValue(now));
+			oneOf(scheduler).schedule(with(any(Runnable.class)),
+					with((long) pollingInterval), with(MILLISECONDS));
+			will(returnValue(future));
+			// connectToContact()
+			// Check whether the contact is already connected
+			oneOf(connectionRegistry).isConnected(contactId, transportId);
+			will(returnValue(false));
+			// Get the transport properties
+			oneOf(transportPropertyManager).getRemoteProperties(contactId,
+					transportId);
+			will(returnValue(properties));
+			// Connect to the contact
+			oneOf(plugin).createConnection(properties);
+			will(returnValue(duplexConnection));
+			// Pass the connection to the connection manager
+			oneOf(connectionManager).manageOutgoingConnection(contactId,
+					transportId, duplexConnection);
 		}});
-		expectReschedule(plugin);
-		expectReconnect(plugin, duplexConnection);
 
 		poller.eventOccurred(new ConnectionClosedEvent(contactId, transportId,
-				false, true));
-	}
-
-	@Test
-	public void testRescheduleOnIncomingConnectionClosed() {
-		DuplexPlugin plugin = context.mock(DuplexPlugin.class);
-
-		context.checking(new Expectations() {{
-			allowing(plugin).getId();
-			will(returnValue(transportId));
-		}});
-		expectReschedule(plugin);
-
-		poller.eventOccurred(new ConnectionClosedEvent(contactId, transportId,
-				true, false));
-	}
-
-	@Test
-	public void testRescheduleOnIncomingConnectionFailed() {
-		DuplexPlugin plugin = context.mock(DuplexPlugin.class);
-
-		context.checking(new Expectations() {{
-			allowing(plugin).getId();
-			will(returnValue(transportId));
-		}});
-		expectReschedule(plugin);
-
-		poller.eventOccurred(new ConnectionClosedEvent(contactId, transportId,
-				true, false));
+				false));
 	}
 
 	@Test
@@ -331,7 +322,7 @@ 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() {{
@@ -360,17 +351,20 @@ public class PollerImplTest extends BrambleMockTestCase {
 			oneOf(scheduler).schedule(with(any(Runnable.class)),
 					with((long) (pollingInterval * 0.5)), with(MILLISECONDS));
 			will(returnValue(future));
+			// FIXME: Revert
+			oneOf(plugin).supportsDiscovery();
+			will(returnValue(false));
 			// Get the transport properties and connected contacts
 			oneOf(transportPropertyManager).getRemoteProperties(transportId);
 			will(returnValue(singletonMap(contactId, properties)));
-			oneOf(connectionRegistry).getConnectedOrBetterContacts(transportId);
+			oneOf(connectionRegistry).getConnectedContacts(transportId);
 			will(returnValue(emptyList()));
 			// Poll the plugin
-			oneOf(plugin).poll(with(collectionOf(
-					pairOf(equal(properties), any(ConnectionHandler.class)))));
+			oneOf(plugin).poll(with(listOf(pairOf(
+					equal(properties), any(ConnectionHandler.class)))));
 		}});
 
-		poller.eventOccurred(new TransportEnabledEvent(transportId));
+		poller.eventOccurred(new TransportActiveEvent(transportId));
 	}
 
 	@Test
@@ -403,19 +397,22 @@ public class PollerImplTest extends BrambleMockTestCase {
 			oneOf(scheduler).schedule(with(any(Runnable.class)),
 					with((long) (pollingInterval * 0.5)), with(MILLISECONDS));
 			will(returnValue(future));
+			// FIXME: Revert
+			oneOf(plugin).supportsDiscovery();
+			will(returnValue(false));
 			// Get the transport properties and connected contacts
 			oneOf(transportPropertyManager).getRemoteProperties(transportId);
 			will(returnValue(singletonMap(contactId, properties)));
-			oneOf(connectionRegistry).getConnectedOrBetterContacts(transportId);
+			oneOf(connectionRegistry).getConnectedContacts(transportId);
 			will(returnValue(singletonList(contactId)));
 			// 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() {{
@@ -433,55 +430,11 @@ public class PollerImplTest extends BrambleMockTestCase {
 			oneOf(scheduler).schedule(with(any(Runnable.class)), with(0L),
 					with(MILLISECONDS));
 			will(returnValue(future));
-			// 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);
 		}});
 
-		poller.eventOccurred(new TransportEnabledEvent(transportId));
-		poller.eventOccurred(new TransportDisabledEvent(transportId));
-	}
-
-	private void expectReschedule(Plugin plugin) {
-		context.checking(new Expectations() {{
-			// Get the plugin
-			oneOf(pluginManager).getPlugin(transportId);
-			will(returnValue(plugin));
-			// The plugin supports polling
-			oneOf(plugin).shouldPoll();
-			will(returnValue(true));
-			// Schedule the next poll
-			oneOf(plugin).getPollingInterval();
-			will(returnValue(pollingInterval));
-			oneOf(clock).currentTimeMillis();
-			will(returnValue(now));
-			oneOf(scheduler).schedule(with(any(Runnable.class)),
-					with((long) pollingInterval), with(MILLISECONDS));
-			will(returnValue(future));
-		}});
-	}
-
-	private void expectReconnect(DuplexPlugin plugin,
-			DuplexTransportConnection duplexConnection) throws Exception {
-		context.checking(new Expectations() {{
-			// Get the plugin
-			oneOf(pluginManager).getPlugin(transportId);
-			will(returnValue(plugin));
-			// The plugin supports polling
-			oneOf(plugin).shouldPoll();
-			will(returnValue(true));
-			// Check whether the contact is already connected
-			oneOf(connectionRegistry).isConnected(contactId, transportId);
-			will(returnValue(false));
-			// Get the transport properties
-			oneOf(transportPropertyManager).getRemoteProperties(contactId,
-					transportId);
-			will(returnValue(properties));
-			// Connect to the contact
-			oneOf(plugin).createConnection(properties);
-			will(returnValue(duplexConnection));
-			// Pass the connection to the connection manager
-			oneOf(connectionManager).manageOutgoingConnection(contactId,
-					transportId, duplexConnection);
-		}});
+		poller.eventOccurred(new TransportActiveEvent(transportId));
+		poller.eventOccurred(new TransportInactiveEvent(transportId));
 	}
 }

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;
@@ -31,6 +32,7 @@ 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;
@@ -302,10 +304,15 @@ 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
@@ -324,11 +331,7 @@ public class LanTcpPluginTest extends BrambleTestCase {
 		}
 
 		@Override
-		public void transportEnabled() {
-		}
-
-		@Override
-		public void transportDisabled() {
+		public void pluginStateChanged(State newState) {
 		}
 
 		@Override

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

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

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

@@ -1,6 +1,5 @@
 package org.briarproject.bramble.rendezvous;
 
-import org.briarproject.bramble.api.connection.ConnectionManager;
 import org.briarproject.bramble.api.contact.PendingContact;
 import org.briarproject.bramble.api.contact.PendingContactState;
 import org.briarproject.bramble.api.contact.event.PendingContactAddedEvent;
@@ -14,11 +13,12 @@ import org.briarproject.bramble.api.db.Transaction;
 import org.briarproject.bramble.api.event.EventBus;
 import org.briarproject.bramble.api.identity.IdentityManager;
 import org.briarproject.bramble.api.plugin.ConnectionHandler;
+import org.briarproject.bramble.api.plugin.ConnectionManager;
 import org.briarproject.bramble.api.plugin.PluginManager;
 import org.briarproject.bramble.api.plugin.TransportId;
 import org.briarproject.bramble.api.plugin.duplex.DuplexPlugin;
-import org.briarproject.bramble.api.plugin.event.TransportDisabledEvent;
-import org.briarproject.bramble.api.plugin.event.TransportEnabledEvent;
+import org.briarproject.bramble.api.plugin.event.TransportActiveEvent;
+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;
@@ -49,7 +49,7 @@ 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.rendezvous.RendezvousConstants.POLLING_INTERVAL_MS;
 import static org.briarproject.bramble.rendezvous.RendezvousConstants.RENDEZVOUS_TIMEOUT_MS;
-import static org.briarproject.bramble.test.CollectionMatcher.collectionOf;
+import static org.briarproject.bramble.test.ListMatcher.listOf;
 import static org.briarproject.bramble.test.PairMatcher.pairOf;
 import static org.briarproject.bramble.test.TestUtils.getAgreementPrivateKey;
 import static org.briarproject.bramble.test.TestUtils.getAgreementPublicKey;
@@ -178,10 +178,10 @@ 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
@@ -196,7 +196,7 @@ public class RendezvousPollerImplTest extends BrambleMockTestCase {
 			oneOf(clock).currentTimeMillis();
 			will(returnValue(beforeExpiry));
 			oneOf(eventBus).broadcast(with(any(RendezvousPollEvent.class)));
-			oneOf(plugin).poll(with(collectionOf(pairOf(
+			oneOf(plugin).poll(with(listOf(pairOf(
 					equal(transportProperties),
 					any(ConnectionHandler.class)))));
 		}});
@@ -212,8 +212,8 @@ public class RendezvousPollerImplTest extends BrambleMockTestCase {
 				new PendingContactRemovedEvent(pendingContact.getId()));
 		context.assertIsSatisfied();
 
-		// Disable the transport - endpoint is already closed
-		rendezvousPoller.eventOccurred(new TransportDisabledEvent(transportId));
+		// Deactivate the transport - endpoint is already closed
+		rendezvousPoller.eventOccurred(new TransportInactiveEvent(transportId));
 	}
 
 	@Test
@@ -230,10 +230,10 @@ 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
@@ -248,7 +248,7 @@ public class RendezvousPollerImplTest extends BrambleMockTestCase {
 			oneOf(clock).currentTimeMillis();
 			will(returnValue(beforeExpiry));
 			oneOf(eventBus).broadcast(with(any(RendezvousPollEvent.class)));
-			oneOf(plugin).poll(with(collectionOf(pairOf(
+			oneOf(plugin).poll(with(listOf(pairOf(
 					equal(transportProperties),
 					any(ConnectionHandler.class)))));
 		}});
@@ -269,12 +269,12 @@ public class RendezvousPollerImplTest extends BrambleMockTestCase {
 				new PendingContactRemovedEvent(pendingContact.getId()));
 		context.assertIsSatisfied();
 
-		// Disable the transport - endpoint is already closed
-		rendezvousPoller.eventOccurred(new TransportDisabledEvent(transportId));
+		// Deactivate the transport - endpoint is already closed
+		rendezvousPoller.eventOccurred(new TransportInactiveEvent(transportId));
 	}
 
 	@Test
-	public void testCreatesAndClosesEndpointsWhenTransportIsEnabledAndDisabled()
+	public void testCreatesAndClosesEndpointsWhenTransportIsActivatedAndDeactivated()
 			throws Exception {
 		long beforeExpiry = pendingContact.getTimestamp();
 
@@ -292,19 +292,19 @@ public class RendezvousPollerImplTest extends BrambleMockTestCase {
 				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

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

@@ -8,7 +8,6 @@ import org.briarproject.bramble.api.record.RecordReader;
 import org.briarproject.bramble.api.sync.Ack;
 import org.briarproject.bramble.api.sync.MessageFactory;
 import org.briarproject.bramble.api.sync.Offer;
-import org.briarproject.bramble.api.sync.Priority;
 import org.briarproject.bramble.api.sync.Request;
 import org.briarproject.bramble.api.sync.SyncRecordReader;
 import org.briarproject.bramble.api.sync.Versions;
@@ -25,14 +24,11 @@ import javax.annotation.Nullable;
 import static org.briarproject.bramble.api.record.Record.MAX_RECORD_PAYLOAD_BYTES;
 import static org.briarproject.bramble.api.sync.RecordTypes.ACK;
 import static org.briarproject.bramble.api.sync.RecordTypes.OFFER;
-import static org.briarproject.bramble.api.sync.RecordTypes.PRIORITY;
 import static org.briarproject.bramble.api.sync.RecordTypes.REQUEST;
 import static org.briarproject.bramble.api.sync.RecordTypes.VERSIONS;
 import static org.briarproject.bramble.api.sync.SyncConstants.MAX_MESSAGE_IDS;
 import static org.briarproject.bramble.api.sync.SyncConstants.MAX_SUPPORTED_VERSIONS;
-import static org.briarproject.bramble.api.sync.SyncConstants.PRIORITY_NONCE_BYTES;
 import static org.briarproject.bramble.api.sync.SyncConstants.PROTOCOL_VERSION;
-import static org.briarproject.bramble.test.TestUtils.getRandomBytes;
 import static org.briarproject.bramble.test.TestUtils.getRandomId;
 import static org.junit.Assert.assertEquals;
 import static org.junit.Assert.assertFalse;
@@ -123,31 +119,6 @@ public class SyncRecordReaderImplTest extends BrambleMockTestCase {
 		reader.readVersions();
 	}
 
-	@Test(expected = FormatException.class)
-	public void testFormatExceptionIfPriorityNonceIsTooSmall()
-			throws Exception {
-		expectReadRecord(createPriority(PRIORITY_NONCE_BYTES - 1));
-
-		reader.readPriority();
-	}
-
-	@Test(expected = FormatException.class)
-	public void testFormatExceptionIfPriorityNonceIsTooLarge()
-			throws Exception {
-		expectReadRecord(createPriority(PRIORITY_NONCE_BYTES + 1));
-
-		reader.readPriority();
-	}
-
-	@Test
-	public void testNoFormatExceptionIfPriorityNonceIsCorrectSize()
-			throws Exception {
-		expectReadRecord(createPriority(PRIORITY_NONCE_BYTES));
-
-		Priority priority = reader.readPriority();
-		assertEquals(PRIORITY_NONCE_BYTES, priority.getNonce().length);
-	}
-
 	@Test
 	public void testEofReturnsTrueWhenAtEndOfStream() throws Exception {
 		expectReadRecord(createAck());
@@ -202,11 +173,6 @@ public class SyncRecordReaderImplTest extends BrambleMockTestCase {
 		return new Record(PROTOCOL_VERSION, VERSIONS, payload);
 	}
 
-	private Record createPriority(int nonceBytes) {
-		byte[] payload = getRandomBytes(nonceBytes);
-		return new Record(PROTOCOL_VERSION, PRIORITY, payload);
-	}
-
 	private byte[] createPayload() throws Exception {
 		ByteArrayOutputStream payload = new ByteArrayOutputStream();
 		while (payload.size() + UniqueId.LENGTH <= MAX_RECORD_PAYLOAD_BYTES) {

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

@@ -5,24 +5,24 @@ import org.hamcrest.BaseMatcher;
 import org.hamcrest.Description;
 import org.hamcrest.Matcher;
 
-import java.util.Collection;
+import java.util.List;
 
 import javax.annotation.Nullable;
 
 @NotNullByDefault
-public class CollectionMatcher<T> extends BaseMatcher<Collection<T>> {
+public class ListMatcher<T> extends BaseMatcher<List<T>> {
 
 	private final Matcher<T> elementMatcher;
 
-	public CollectionMatcher(Matcher<T> elementMatcher) {
+	public ListMatcher(Matcher<T> elementMatcher) {
 		this.elementMatcher = elementMatcher;
 	}
 
 	@Override
 	public boolean matches(@Nullable Object item) {
-		if (!(item instanceof Collection)) return false;
-		Collection collection = (Collection) item;
-		for (Object element : collection) {
+		if (!(item instanceof List)) return false;
+		List list = (List) item;
+		for (Object element : list) {
 			if (!elementMatcher.matches(element)) return false;
 		}
 		return true;
@@ -33,7 +33,7 @@ public class CollectionMatcher<T> extends BaseMatcher<Collection<T>> {
 		description.appendText("matches a collection");
 	}
 
-	public static <T> CollectionMatcher<T> collectionOf(Matcher<T> t) {
-		return new CollectionMatcher<>(t);
+	public static <T> ListMatcher<T> listOf(Matcher<T> t) {
+		return new ListMatcher<>(t);
 	}
 }

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

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