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

@@ -8,23 +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.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;
@@ -46,15 +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
@@ -63,7 +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;
@@ -137,17 +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() {
@@ -202,7 +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));
@@ -218,10 +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);
@@ -229,8 +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;
@@ -239,17 +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();
@@ -265,9 +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 {
@@ -288,11 +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/AndroidBluetoothTransportConnection.java

@@ -10,9 +10,6 @@ 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 {
@@ -26,8 +23,6 @@ class AndroidBluetoothTransportConnection
 		super(plugin);
 		this.connectionManager = connectionManager;
 		this.socket = socket;
-		String address = socket.getRemoteDevice().getAddress();
-		if (isValidBluetoothAddress(address)) remote.put(PROP_ADDRESS, address);
 	}
 
 	@Override

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/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/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/ConnectionRegistry.java

@@ -5,7 +5,8 @@ import org.briarproject.bramble.api.contact.PendingContactId;
 import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
 import org.briarproject.bramble.api.plugin.event.ConnectionClosedEvent;
 import org.briarproject.bramble.api.plugin.event.ConnectionOpenedEvent;
-import org.briarproject.bramble.api.plugin.event.ConnectionStatusChangedEvent;
+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;
 
@@ -20,15 +21,15 @@ public interface ConnectionRegistry {
 	/**
 	 * Registers a connection with the given contact over the given transport.
 	 * Broadcasts {@link ConnectionOpenedEvent}. Also broadcasts
-	 * {@link ConnectionStatusChangedEvent} if this is the only connection with
-	 * the contact.
+	 * {@link ContactConnectedEvent} if this is the only connection with the
+	 * contact.
 	 */
 	void registerConnection(ContactId c, TransportId t, boolean incoming);
 
 	/**
 	 * Unregisters a connection with the given contact over the given transport.
 	 * Broadcasts {@link ConnectionClosedEvent}. Also broadcasts
-	 * {@link ConnectionStatusChangedEvent} if this is the only connection with
+	 * {@link ContactDisconnectedEvent} if this is the only connection with
 	 * the contact.
 	 */
 	void unregisterConnection(ContactId c, TransportId t, boolean incoming);
@@ -44,9 +45,9 @@ public interface ConnectionRegistry {
 	boolean isConnected(ContactId c, TransportId t);
 
 	/**
-	 * Returns the connection status of the given contact via all transports.
+	 * Returns true if the given contact is connected via any transport.
 	 */
-	ConnectionStatus getConnectionStatus(ContactId c);
+	boolean isConnected(ContactId c);
 
 	/**
 	 * Registers a connection with the given pending contact. Broadcasts

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

@@ -1,5 +0,0 @@
-package org.briarproject.bramble.api.plugin;
-
-public enum ConnectionStatus {
-	CONNECTED, RECENTLY_CONNECTED, DISCONNECTED
-}

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/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/ContactConnectedEvent.java

@@ -3,31 +3,24 @@ package org.briarproject.bramble.api.plugin.event;
 import org.briarproject.bramble.api.contact.ContactId;
 import org.briarproject.bramble.api.event.Event;
 import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
-import org.briarproject.bramble.api.plugin.ConnectionStatus;
 
 import javax.annotation.concurrent.Immutable;
 
 /**
- * An event that is broadcast when a contact's connection status changes.
+ * An event that is broadcast when a contact connects that was not previously
+ * connected via any transport.
  */
 @Immutable
 @NotNullByDefault
-public class ConnectionStatusChangedEvent extends Event {
+public class ContactConnectedEvent extends Event {
 
 	private final ContactId contactId;
-	private final ConnectionStatus status;
 
-	public ConnectionStatusChangedEvent(ContactId contactId,
-			ConnectionStatus status) {
+	public ContactConnectedEvent(ContactId contactId) {
 		this.contactId = contactId;
-		this.status = status;
 	}
 
 	public ContactId getContactId() {
 		return contactId;
 	}
-
-	public ConnectionStatus getConnectionStatus() {
-		return status;
-	}
 }

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

@@ -0,0 +1,26 @@
+package org.briarproject.bramble.api.plugin.event;
+
+import org.briarproject.bramble.api.contact.ContactId;
+import org.briarproject.bramble.api.event.Event;
+import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
+
+import javax.annotation.concurrent.Immutable;
+
+/**
+ * An event that is broadcast when a contact disconnects and is no longer
+ * connected via any transport.
+ */
+@Immutable
+@NotNullByDefault
+public class ContactDisconnectedEvent extends Event {
+
+	private final ContactId contactId;
+
+	public ContactDisconnectedEvent(ContactId contactId) {
+		this.contactId = contactId;
+	}
+
+	public ContactId getContactId() {
+		return contactId;
+	}
+}

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 enabled.
+ * An event that is broadcast when a plugin enters the {@link State#ACTIVE}
+ * state.
  */
 @Immutable
 @NotNullByDefault
-public class TransportEnabledEvent extends Event {
+public class TransportActiveEvent extends Event {
 
 	private final TransportId transportId;
 
-	public TransportEnabledEvent(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 disabled.
+ * An event that is broadcast when a plugin leaves the {@link State#ACTIVE}
+ * state.
  */
 @Immutable
 @NotNullByDefault
-public class TransportDisabledEvent extends Event {
+public class TransportInactiveEvent extends Event {
 
 	private final TransportId transportId;
 
-	public TransportDisabledEvent(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/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/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/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/plugin/ConnectionManagerImpl.java

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

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

@@ -6,41 +6,30 @@ 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.ConnectionStatus;
 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.ConnectionStatusChangedEvent;
+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.system.Clock;
-import org.briarproject.bramble.api.system.Scheduler;
 
 import java.util.ArrayList;
 import java.util.Collection;
+import java.util.Collections;
 import java.util.HashMap;
 import java.util.HashSet;
-import java.util.Iterator;
 import java.util.List;
 import java.util.Map;
-import java.util.Map.Entry;
 import java.util.Set;
-import java.util.concurrent.ScheduledExecutorService;
 import java.util.logging.Logger;
 
 import javax.annotation.concurrent.GuardedBy;
 import javax.annotation.concurrent.ThreadSafe;
 import javax.inject.Inject;
 
-import static java.util.Collections.emptyList;
-import static java.util.concurrent.TimeUnit.MILLISECONDS;
-import static java.util.concurrent.TimeUnit.MINUTES;
-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.api.plugin.ConnectionStatus.CONNECTED;
-import static org.briarproject.bramble.api.plugin.ConnectionStatus.DISCONNECTED;
-import static org.briarproject.bramble.api.plugin.ConnectionStatus.RECENTLY_CONNECTED;
 
 @ThreadSafe
 @NotNullByDefault
@@ -49,30 +38,22 @@ class ConnectionRegistryImpl implements ConnectionRegistry {
 	private static final Logger LOG =
 			getLogger(ConnectionRegistryImpl.class.getName());
 
-	private static final long RECENTLY_CONNECTED_MS = MINUTES.toMillis(1);
-	private static final long EXPIRY_INTERVAL_MS = SECONDS.toMillis(10);
-
 	private final EventBus eventBus;
-	private final Clock clock;
 
 	private final Object lock = new Object();
 	@GuardedBy("lock")
 	private final Map<TransportId, Multiset<ContactId>> contactConnections;
 	@GuardedBy("lock")
-	private final Map<ContactId, Counter> contactCounts;
+	private final Multiset<ContactId> contactCounts;
 	@GuardedBy("lock")
 	private final Set<PendingContactId> connectedPendingContacts;
 
 	@Inject
-	ConnectionRegistryImpl(EventBus eventBus, Clock clock,
-			@Scheduler ScheduledExecutorService scheduler) {
+	ConnectionRegistryImpl(EventBus eventBus) {
 		this.eventBus = eventBus;
-		this.clock = clock;
 		contactConnections = new HashMap<>();
-		contactCounts = new HashMap<>();
+		contactCounts = new Multiset<>();
 		connectedPendingContacts = new HashSet<>();
-		scheduler.scheduleWithFixedDelay(this::expireRecentConnections,
-				EXPIRY_INTERVAL_MS, EXPIRY_INTERVAL_MS, MILLISECONDS);
 	}
 
 	@Override
@@ -90,22 +71,12 @@ class ConnectionRegistryImpl implements ConnectionRegistry {
 				contactConnections.put(t, m);
 			}
 			m.add(c);
-
-			Counter counter = contactCounts.get(c);
-			if (counter == null) {
-				counter = new Counter();
-				contactCounts.put(c, counter);
-			}
-			if (counter.connections == 0) {
-				counter.disconnectedTime = 0;
-				firstConnection = true;
-			}
-			counter.connections++;
+			if (contactCounts.add(c) == 1) firstConnection = true;
 		}
 		eventBus.broadcast(new ConnectionOpenedEvent(c, t, incoming));
 		if (firstConnection) {
 			LOG.info("Contact connected");
-			eventBus.broadcast(new ConnectionStatusChangedEvent(c, CONNECTED));
+			eventBus.broadcast(new ContactConnectedEvent(c));
 		}
 	}
 
@@ -122,22 +93,12 @@ class ConnectionRegistryImpl implements ConnectionRegistry {
 			if (m == null || !m.contains(c))
 				throw new IllegalArgumentException();
 			m.remove(c);
-
-			Counter counter = contactCounts.get(c);
-			if (counter == null || counter.connections == 0) {
-				throw new IllegalArgumentException();
-			}
-			counter.connections--;
-			if (counter.connections == 0) {
-				counter.disconnectedTime = clock.currentTimeMillis();
-				lastConnection = true;
-			}
+			if (contactCounts.remove(c) == 0) lastConnection = true;
 		}
 		eventBus.broadcast(new ConnectionClosedEvent(c, t, incoming));
 		if (lastConnection) {
 			LOG.info("Contact disconnected");
-			eventBus.broadcast(
-					new ConnectionStatusChangedEvent(c, RECENTLY_CONNECTED));
+			eventBus.broadcast(new ContactDisconnectedEvent(c));
 		}
 	}
 
@@ -145,7 +106,7 @@ class ConnectionRegistryImpl implements ConnectionRegistry {
 	public Collection<ContactId> getConnectedContacts(TransportId t) {
 		synchronized (lock) {
 			Multiset<ContactId> m = contactConnections.get(t);
-			if (m == null) return emptyList();
+			if (m == null) return Collections.emptyList();
 			List<ContactId> ids = new ArrayList<>(m.keySet());
 			if (LOG.isLoggable(INFO))
 				LOG.info(ids.size() + " contacts connected: " + t);
@@ -162,11 +123,9 @@ class ConnectionRegistryImpl implements ConnectionRegistry {
 	}
 
 	@Override
-	public ConnectionStatus getConnectionStatus(ContactId c) {
+	public boolean isConnected(ContactId c) {
 		synchronized (lock) {
-			Counter counter = contactCounts.get(c);
-			if (counter == null) return DISCONNECTED;
-			return counter.connections > 0 ? CONNECTED : RECENTLY_CONNECTED;
+			return contactCounts.contains(c);
 		}
 	}
 
@@ -188,36 +147,4 @@ class ConnectionRegistryImpl implements ConnectionRegistry {
 		}
 		eventBus.broadcast(new RendezvousConnectionClosedEvent(p, success));
 	}
-
-	@Scheduler
-	private void expireRecentConnections() {
-		long now = clock.currentTimeMillis();
-		List<ContactId> disconnected = new ArrayList<>();
-		synchronized (lock) {
-			Iterator<Entry<ContactId, Counter>> it =
-					contactCounts.entrySet().iterator();
-			while (it.hasNext()) {
-				Entry<ContactId, Counter> e = it.next();
-				if (e.getValue().isExpired(now)) {
-					disconnected.add(e.getKey());
-					it.remove();
-				}
-			}
-		}
-		for (ContactId c : disconnected) {
-			eventBus.broadcast(
-					new ConnectionStatusChangedEvent(c, DISCONNECTED));
-		}
-	}
-
-	private static class Counter {
-
-		private int connections = 0;
-		private long disconnectedTime = 0;
-
-		private boolean isExpired(long now) {
-			return connections == 0 &&
-					now - disconnectedTime > RECENTLY_CONNECTED_MS;
-		}
-	}
 }

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

@@ -8,6 +8,7 @@ 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/PollerImpl.java

@@ -11,6 +11,7 @@ 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;
@@ -106,13 +108,13 @@ class PollerImpl implements Poller, EventListener {
 			ConnectionOpenedEvent c = (ConnectionOpenedEvent) e;
 			// Reschedule polling, the polling interval may have decreased
 			reschedule(c.getTransportId());
-		} else if (e instanceof TransportEnabledEvent) {
-			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.getConnectedContacts(t);
-			Collection<Pair<TransportProperties, ConnectionHandler>>
-					properties = new ArrayList<>();
+			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

@@ -9,10 +9,13 @@ 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;
@@ -29,23 +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;
@@ -68,9 +76,9 @@ abstract class BluetoothPlugin<SS> implements DuplexPlugin, EventListener {
 	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;
 
@@ -119,14 +127,18 @@ abstract class BluetoothPlugin<SS> implements DuplexPlugin, EventListener {
 		LOG.info("Bluetooth enabled");
 		// We may not have been able to get the local address before
 		ioExecutor.execute(this::updateProperties);
-		if (shouldAllowContactConnections()) bind();
+		if (getState() == INACTIVE) bind();
 	}
 
 	void onAdapterDisabled() {
 		LOG.info("Bluetooth disabled");
-		tryToClose(socket);
 		connectionLimiter.allConnectionsClosed();
-		callback.transportDisabled();
+		// The server socket may not have been closed automatically
+		SS ss = state.clearServerSocket();
+		if (ss != null) {
+			LOG.info("Closing server socket");
+			tryToClose(ss);
+		}
 	}
 
 	@Override
@@ -148,31 +160,24 @@ abstract class BluetoothPlugin<SS> implements DuplexPlugin, EventListener {
 	@Override
 	public void start() throws PluginException {
 		if (used.getAndSet(true)) throw new IllegalStateException();
+		Settings settings = callback.getSettings();
+		boolean enabledByUser = settings.getBoolean(PREF_PLUGIN_ENABLE, 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 {
@@ -181,14 +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);
 		});
 	}
 
@@ -217,34 +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");
 			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
@@ -258,9 +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());
@@ -273,7 +282,7 @@ abstract class BluetoothPlugin<SS> implements DuplexPlugin, EventListener {
 		String uuid = p.get(PROP_UUID);
 		if (isNullOrEmpty(uuid)) return;
 		ioExecutor.execute(() -> {
-			if (!isRunning() || !shouldAllowContactConnections()) return;
+			if (getState() != ACTIVE) return;
 			if (!connectionLimiter.canOpenContactConnection()) return;
 			DuplexTransportConnection d = createConnection(p);
 			if (d != null) {
@@ -317,7 +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;
@@ -336,7 +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);
@@ -348,7 +357,7 @@ abstract class BluetoothPlugin<SS> implements DuplexPlugin, EventListener {
 			logException(LOG, WARNING, e);
 			return null;
 		}
-		if (!isRunning()) {
+		if (getState() != ACTIVE) {
 			tryToClose(ss);
 			return null;
 		}
@@ -362,7 +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;
@@ -403,6 +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) {
@@ -422,17 +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();
 		}
@@ -460,4 +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

@@ -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/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/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/plugin/ConnectionRegistryImplTest.java

@@ -7,20 +7,18 @@ 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.ConnectionStatusChangedEvent;
+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.system.Clock;
 import org.briarproject.bramble.test.BrambleMockTestCase;
 import org.jmock.Expectations;
 import org.junit.Test;
 
 import java.util.Collection;
-import java.util.concurrent.ScheduledExecutorService;
 
 import static java.util.Collections.emptyList;
 import static java.util.Collections.singletonList;
-import static java.util.concurrent.TimeUnit.MILLISECONDS;
 import static org.briarproject.bramble.test.TestUtils.getContactId;
 import static org.briarproject.bramble.test.TestUtils.getRandomId;
 import static org.briarproject.bramble.test.TestUtils.getTransportId;
@@ -32,9 +30,6 @@ import static org.junit.Assert.fail;
 public class ConnectionRegistryImplTest extends BrambleMockTestCase {
 
 	private final EventBus eventBus = context.mock(EventBus.class);
-	private final Clock clock = context.mock(Clock.class);
-	private final ScheduledExecutorService scheduler =
-			context.mock(ScheduledExecutorService.class);
 
 	private final ContactId contactId = getContactId();
 	private final ContactId contactId1 = getContactId();
@@ -45,25 +40,17 @@ public class ConnectionRegistryImplTest extends BrambleMockTestCase {
 
 	@Test
 	public void testRegisterAndUnregister() {
-		context.checking(new Expectations() {{
-			oneOf(scheduler).scheduleWithFixedDelay(with(any(Runnable.class)),
-					with(10_000L), with(10_000L), with(MILLISECONDS));
-		}});
-
-		ConnectionRegistry c = new ConnectionRegistryImpl(eventBus, clock,
-				scheduler);
-		context.assertIsSatisfied();
+		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 ConnectionStatusChangedEvent
+		// broadcast a ConnectionOpenedEvent and a ContactConnectedEvent
 		context.checking(new Expectations() {{
 			oneOf(eventBus).broadcast(with(any(ConnectionOpenedEvent.class)));
-			oneOf(eventBus).broadcast(with(any(
-					ConnectionStatusChangedEvent.class)));
+			oneOf(eventBus).broadcast(with(any(ContactConnectedEvent.class)));
 		}});
 		c.registerConnection(contactId, transportId, true);
 		assertEquals(singletonList(contactId),
@@ -94,13 +81,11 @@ public class ConnectionRegistryImplTest extends BrambleMockTestCase {
 		context.assertIsSatisfied();
 
 		// Unregister the other connection - this should broadcast a
-		// ConnectionClosedEvent and a ConnectionStatusChangedEvent
+		// ConnectionClosedEvent and a ContactDisconnectedEvent
 		context.checking(new Expectations() {{
-			oneOf(clock).currentTimeMillis();
-			will(returnValue(System.currentTimeMillis()));
 			oneOf(eventBus).broadcast(with(any(ConnectionClosedEvent.class)));
 			oneOf(eventBus).broadcast(with(any(
-					ConnectionStatusChangedEvent.class)));
+					ContactDisconnectedEvent.class)));
 		}});
 		c.unregisterConnection(contactId, transportId, true);
 		assertEquals(emptyList(), c.getConnectedContacts(transportId));
@@ -117,12 +102,12 @@ public class ConnectionRegistryImplTest extends BrambleMockTestCase {
 
 		// Register both contacts with one transport, one contact with both -
 		// this should broadcast three ConnectionOpenedEvents and two
-		// ConnectionStatusChangedEvents
+		// ContactConnectedEvents
 		context.checking(new Expectations() {{
 			exactly(3).of(eventBus).broadcast(with(any(
 					ConnectionOpenedEvent.class)));
 			exactly(2).of(eventBus).broadcast(with(any(
-					ConnectionStatusChangedEvent.class)));
+					ContactConnectedEvent.class)));
 		}});
 		c.registerConnection(contactId, transportId, true);
 		c.registerConnection(contactId1, transportId, true);
@@ -137,14 +122,7 @@ public class ConnectionRegistryImplTest extends BrambleMockTestCase {
 
 	@Test
 	public void testRegisterAndUnregisterPendingContacts() {
-		context.checking(new Expectations() {{
-			oneOf(scheduler).scheduleWithFixedDelay(with(any(Runnable.class)),
-					with(10_000L), with(10_000L), with(MILLISECONDS));
-		}});
-
-		ConnectionRegistry c = new ConnectionRegistryImpl(eventBus, clock,
-				scheduler);
-		context.assertIsSatisfied();
+		ConnectionRegistry c = new ConnectionRegistryImpl(eventBus);
 
 		context.checking(new Expectations() {{
 			oneOf(eventBus).broadcast(with(any(

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

@@ -13,8 +13,8 @@ import org.briarproject.bramble.api.plugin.duplex.DuplexPlugin;
 import org.briarproject.bramble.api.plugin.duplex.DuplexTransportConnection;
 import org.briarproject.bramble.api.plugin.event.ConnectionClosedEvent;
 import org.briarproject.bramble.api.plugin.event.ConnectionOpenedEvent;
-import org.briarproject.bramble.api.plugin.event.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;
@@ -322,7 +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() {{
@@ -351,17 +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).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
@@ -394,6 +397,9 @@ 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)));
@@ -402,11 +408,11 @@ public class PollerImplTest extends BrambleMockTestCase {
 			// All contacts are connected, so don't poll the plugin
 		}});
 
-		poller.eventOccurred(new TransportEnabledEvent(transportId));
+		poller.eventOccurred(new TransportActiveEvent(transportId));
 	}
 
 	@Test
-	public void testCancelsPollingOnTransportDisabled() {
+	public void testCancelsPollingOnTransportDeactivated() {
 		Plugin plugin = context.mock(Plugin.class);
 
 		context.checking(new Expectations() {{
@@ -424,11 +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));
+		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

@@ -17,8 +17,8 @@ import org.briarproject.bramble.api.plugin.ConnectionManager;
 import org.briarproject.bramble.api.plugin.PluginManager;
 import org.briarproject.bramble.api.plugin.TransportId;
 import org.briarproject.bramble.api.plugin.duplex.DuplexPlugin;
-import org.briarproject.bramble.api.plugin.event.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/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.

bramble-java/build.gradle

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

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

@@ -37,9 +37,9 @@ public class DesktopPluginModule extends PluginModule {
 						backoffFactory);
 		DuplexPluginFactory modem = new ModemPluginFactory(ioExecutor,
 				reliabilityFactory);
-		DuplexPluginFactory lan = new LanTcpPluginFactory(ioExecutor,
+		DuplexPluginFactory lan = new LanTcpPluginFactory(ioExecutor, eventBus,
 				backoffFactory);
-		DuplexPluginFactory wan = new WanTcpPluginFactory(ioExecutor,
+		DuplexPluginFactory wan = new WanTcpPluginFactory(ioExecutor, eventBus,
 				backoffFactory, shutdownManager);
 		Collection<DuplexPluginFactory> duplex =
 				asList(bluetooth, modem, lan, wan);

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

@@ -4,8 +4,10 @@ import org.briarproject.bramble.api.Pair;
 import org.briarproject.bramble.api.data.BdfList;
 import org.briarproject.bramble.api.keyagreement.KeyAgreementListener;
 import org.briarproject.bramble.api.nullsafety.MethodsNotNullByDefault;
+import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
 import org.briarproject.bramble.api.nullsafety.ParametersNotNullByDefault;
 import org.briarproject.bramble.api.plugin.ConnectionHandler;
+import org.briarproject.bramble.api.plugin.DiscoveryHandler;
 import org.briarproject.bramble.api.plugin.PluginCallback;
 import org.briarproject.bramble.api.plugin.PluginException;
 import org.briarproject.bramble.api.plugin.TransportId;
@@ -19,13 +21,20 @@ import org.briarproject.bramble.api.rendezvous.RendezvousEndpoint;
 import java.io.IOException;
 import java.io.InputStream;
 import java.io.OutputStream;
-import java.util.Collection;
+import java.util.List;
 import java.util.concurrent.atomic.AtomicBoolean;
 import java.util.logging.Logger;
 
+import javax.annotation.concurrent.GuardedBy;
+import javax.annotation.concurrent.ThreadSafe;
+
 import static java.util.logging.Level.INFO;
 import static java.util.logging.Level.WARNING;
 import static java.util.logging.Logger.getLogger;
+import static org.briarproject.bramble.api.plugin.Plugin.State.ACTIVE;
+import static org.briarproject.bramble.api.plugin.Plugin.State.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.util.LogUtils.logException;
 import static org.briarproject.bramble.util.StringUtils.isNullOrEmpty;
 
@@ -44,8 +53,8 @@ class ModemPlugin implements DuplexPlugin, Modem.Callback {
 	private final PluginCallback callback;
 	private final int maxLatency;
 	private final AtomicBoolean used = new AtomicBoolean(false);
+	private final PluginState state = new PluginState();
 
-	private volatile boolean running = false;
 	private volatile Modem modem = null;
 
 	ModemPlugin(ModemFactory modemFactory, SerialPortList serialPortList,
@@ -75,6 +84,7 @@ class ModemPlugin implements DuplexPlugin, Modem.Callback {
 	@Override
 	public void start() throws PluginException {
 		if (used.getAndSet(true)) throw new IllegalStateException();
+		state.setStarted();
 		for (String portName : serialPortList.getPortNames()) {
 			if (LOG.isLoggable(INFO))
 				LOG.info("Trying to initialise modem on " + portName);
@@ -83,18 +93,20 @@ class ModemPlugin implements DuplexPlugin, Modem.Callback {
 				if (!modem.start()) continue;
 				if (LOG.isLoggable(INFO))
 					LOG.info("Initialised modem on " + portName);
-				running = true;
+				state.setInitialised();
 				return;
 			} catch (IOException e) {
 				logException(LOG, WARNING, e);
 			}
 		}
+		LOG.warning("Failed to initialised modem");
+		state.setFailed();
 		throw new PluginException();
 	}
 
 	@Override
 	public void stop() {
-		running = false;
+		state.setStopped();
 		if (modem != null) {
 			try {
 				modem.stop();
@@ -105,8 +117,13 @@ class ModemPlugin implements DuplexPlugin, Modem.Callback {
 	}
 
 	@Override
-	public boolean isRunning() {
-		return running;
+	public State getState() {
+		return state.getState();
+	}
+
+	@Override
+	public int getReasonsDisabled() {
+		return 0;
 	}
 
 	@Override
@@ -120,13 +137,13 @@ class ModemPlugin implements DuplexPlugin, Modem.Callback {
 	}
 
 	@Override
-	public void poll(Collection<Pair<TransportProperties, ConnectionHandler>>
-			properties) {
+	public void poll(
+			List<Pair<TransportProperties, ConnectionHandler>> properties) {
 		throw new UnsupportedOperationException();
 	}
 
-	private boolean resetModem() {
-		if (!running) return false;
+	private void resetModem() {
+		if (getState() != ACTIVE) return;
 		for (String portName : serialPortList.getPortNames()) {
 			if (LOG.isLoggable(INFO))
 				LOG.info("Trying to initialise modem on " + portName);
@@ -135,18 +152,18 @@ class ModemPlugin implements DuplexPlugin, Modem.Callback {
 				if (!modem.start()) continue;
 				if (LOG.isLoggable(INFO))
 					LOG.info("Initialised modem on " + portName);
-				return true;
+				return;
 			} catch (IOException e) {
 				logException(LOG, WARNING, e);
 			}
 		}
-		running = false;
-		return false;
+		LOG.warning("Failed to initialise modem");
+		state.setFailed();
 	}
 
 	@Override
 	public DuplexTransportConnection createConnection(TransportProperties p) {
-		if (!running) return null;
+		if (getState() != ACTIVE) return null;
 		// Get the ISO 3166 code for the caller's country
 		String fromIso = callback.getLocalProperties().get("iso3166");
 		if (isNullOrEmpty(fromIso)) return null;
@@ -197,6 +214,17 @@ class ModemPlugin implements DuplexPlugin, Modem.Callback {
 		throw new UnsupportedOperationException();
 	}
 
+	@Override
+	public boolean supportsDiscovery() {
+		return false;
+	}
+
+	@Override
+	public void discoverPeers(
+			List<Pair<TransportProperties, DiscoveryHandler>> properties) {
+		throw new UnsupportedOperationException();
+	}
+
 	@Override
 	public void incomingCallConnected() {
 		LOG.info("Incoming call connected");
@@ -232,4 +260,41 @@ class ModemPlugin implements DuplexPlugin, Modem.Callback {
 			if (exception) resetModem();
 		}
 	}
+
+	@ThreadSafe
+	@NotNullByDefault
+	private class PluginState {
+
+		@GuardedBy("this")
+		private boolean started = false,
+				stopped = false,
+				initialised = false,
+				failed = false;
+
+		private synchronized void setStarted() {
+			started = true;
+			callback.pluginStateChanged(getState());
+		}
+
+		private synchronized void setStopped() {
+			stopped = true;
+			callback.pluginStateChanged(getState());
+		}
+
+		private synchronized void setInitialised() {
+			initialised = true;
+			callback.pluginStateChanged(getState());
+		}
+
+		private synchronized void setFailed() {
+			failed = true;
+			callback.pluginStateChanged(getState());
+		}
+
+		private State getState() {
+			if (!started || stopped) return STARTING_STOPPING;
+			if (failed) return INACTIVE;
+			return initialised ? ACTIVE : ENABLING;
+		}
+	}
 }

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

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

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

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

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

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

bramble-java/witness.gradle

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

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

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

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

@@ -36,7 +36,7 @@ import org.briarproject.bramble.util.AndroidUtils;
 import org.briarproject.bramble.util.StringUtils;
 import org.briarproject.briar.android.account.LockManagerImpl;
 import org.briarproject.briar.android.keyagreement.ContactExchangeModule;
-import org.briarproject.briar.android.login.LoginModule;
+import org.briarproject.briar.android.navdrawer.NavDrawerModule;
 import org.briarproject.briar.android.viewmodel.ViewModelModule;
 import org.briarproject.briar.api.android.AndroidNotificationManager;
 import org.briarproject.briar.api.android.DozeWatchdog;
@@ -66,8 +66,8 @@ import static org.briarproject.bramble.api.reporting.ReportingConstants.DEV_PUBL
 import static org.briarproject.briar.android.TestingConstants.IS_DEBUG_BUILD;
 
 @Module(includes = {
+		NavDrawerModule.class,
 		ContactExchangeModule.class,
-		LoginModule.class,
 		ViewModelModule.class
 })
 public class AppModule {

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

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

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

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

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

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

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

@@ -2,38 +2,35 @@ package org.briarproject.briar.android.contact;
 
 import org.briarproject.bramble.api.contact.Contact;
 import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
-import org.briarproject.bramble.api.plugin.ConnectionStatus;
 
 import javax.annotation.concurrent.NotThreadSafe;
 
-import static org.briarproject.bramble.api.plugin.ConnectionStatus.DISCONNECTED;
-
 @NotThreadSafe
 @NotNullByDefault
 public class ContactItem {
 
 	private final Contact contact;
-	private ConnectionStatus status;
+	private boolean connected;
 
 	public ContactItem(Contact contact) {
-		this(contact, DISCONNECTED);
+		this(contact, false);
 	}
 
-	public ContactItem(Contact contact, ConnectionStatus status) {
+	public ContactItem(Contact contact, boolean connected) {
 		this.contact = contact;
-		this.status = status;
+		this.connected = connected;
 	}
 
 	public Contact getContact() {
 		return contact;
 	}
 
-	ConnectionStatus getConnectionStatus() {
-		return status;
+	boolean isConnected() {
+		return connected;
 	}
 
-	void setConnectionStatus(ConnectionStatus status) {
-		this.status = status;
+	void setConnected(boolean connected) {
+		this.connected = connected;
 	}
 
 }

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

@@ -7,7 +7,6 @@ import android.widget.TextView;
 
 import org.briarproject.bramble.api.identity.Author;
 import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
-import org.briarproject.bramble.api.plugin.ConnectionStatus;
 import org.briarproject.briar.R;
 import org.briarproject.briar.android.contact.BaseContactListAdapter.OnContactClickListener;
 
@@ -17,8 +16,6 @@ import androidx.annotation.UiThread;
 import androidx.recyclerview.widget.RecyclerView;
 import im.delight.android.identicons.IdenticonDrawable;
 
-import static org.briarproject.bramble.api.plugin.ConnectionStatus.CONNECTED;
-import static org.briarproject.bramble.api.plugin.ConnectionStatus.RECENTLY_CONNECTED;
 import static org.briarproject.briar.android.util.UiUtils.getContactDisplayName;
 
 @UiThread
@@ -30,7 +27,7 @@ public class ContactItemViewHolder<I extends ContactItem>
 	protected final ImageView avatar;
 	protected final TextView name;
 	@Nullable
-	private final ImageView bulb;
+	protected final ImageView bulb;
 
 	public ContactItemViewHolder(View v) {
 		super(v);
@@ -50,13 +47,10 @@ public class ContactItemViewHolder<I extends ContactItem>
 
 		if (bulb != null) {
 			// online/offline
-			ConnectionStatus status = item.getConnectionStatus();
-			if (status == CONNECTED) {
-				bulb.setImageResource(R.drawable.ic_connected);
-			} else if (status == RECENTLY_CONNECTED) {
-				bulb.setImageResource(R.drawable.ic_recently_connected);
+			if (item.isConnected()) {
+				bulb.setImageResource(R.drawable.contact_connected);
 			} else {
-				bulb.setImageResource(R.drawable.ic_disconnected);
+				bulb.setImageResource(R.drawable.contact_disconnected);
 			}
 		}
 

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

@@ -39,7 +39,7 @@ public class ContactListAdapter extends
 		if (c1.getTimestamp() != c2.getTimestamp()) {
 			return false;
 		}
-		return c1.getConnectionStatus() == c2.getConnectionStatus();
+		return c1.isConnected() == c2.isConnected();
 	}
 
 	@Override

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

@@ -25,8 +25,8 @@ import org.briarproject.bramble.api.event.EventListener;
 import org.briarproject.bramble.api.nullsafety.MethodsNotNullByDefault;
 import org.briarproject.bramble.api.nullsafety.ParametersNotNullByDefault;
 import org.briarproject.bramble.api.plugin.ConnectionRegistry;
-import org.briarproject.bramble.api.plugin.ConnectionStatus;
-import org.briarproject.bramble.api.plugin.event.ConnectionStatusChangedEvent;
+import org.briarproject.bramble.api.plugin.event.ContactConnectedEvent;
+import org.briarproject.bramble.api.plugin.event.ContactDisconnectedEvent;
 import org.briarproject.briar.R;
 import org.briarproject.briar.android.activity.ActivityComponent;
 import org.briarproject.briar.android.contact.BaseContactListAdapter.OnContactClickListener;
@@ -53,6 +53,7 @@ import javax.inject.Inject;
 import androidx.annotation.UiThread;
 import androidx.core.app.ActivityCompat;
 import androidx.core.app.ActivityOptionsCompat;
+import androidx.core.util.Pair;
 import androidx.recyclerview.widget.LinearLayoutManager;
 import io.github.kobakei.materialfabspeeddial.FabSpeedDial;
 import io.github.kobakei.materialfabspeeddial.FabSpeedDial.OnMenuItemClickListener;
@@ -136,15 +137,26 @@ public class ContactListFragment extends BaseFragment implements EventListener,
 					ContactId contactId = item.getContact().getId();
 					i.putExtra(CONTACT_ID, contactId.getInt());
 
-					Bundle options = null;
-					// work-around for android bug #224270
 					if (SDK_INT >= 23 && !isSamsung7()) {
-						options = makeTransitionOptions(view);
-					}
-					if (options == null) {
-						startActivity(i);
+						ContactListItemViewHolder holder =
+								(ContactListItemViewHolder) list
+										.getRecyclerView()
+										.findViewHolderForAdapterPosition(
+												adapter.findItemPosition(item));
+						Pair<View, String> avatar =
+								Pair.create(holder.avatar,
+										getTransitionName(holder.avatar));
+						Pair<View, String> bulb =
+								Pair.create(holder.bulb,
+										getTransitionName(holder.bulb));
+						ActivityOptionsCompat options =
+								makeSceneTransitionAnimation(getActivity(),
+										avatar, bulb);
+						ActivityCompat.startActivity(getActivity(), i,
+								options.toBundle());
 					} else {
-						ActivityCompat.startActivity(getActivity(), i, options);
+						// work-around for android bug #224270
+						startActivity(i);
 					}
 				};
 		adapter = new ContactListAdapter(requireContext(),
@@ -159,15 +171,6 @@ public class ContactListFragment extends BaseFragment implements EventListener,
 		return contentView;
 	}
 
-	@Nullable
-	private Bundle makeTransitionOptions(View view) {
-		View avatar = view.findViewById(R.id.avatarView);
-		String name = requireNonNull(getTransitionName(avatar));
-		ActivityOptionsCompat options = makeSceneTransitionAnimation(
-				requireActivity(), view, name);
-		return options.toBundle();
-	}
-
 	@Override
 	public void onMenuItemClick(FloatingActionButton fab, @Nullable TextView v,
 			int itemId) {
@@ -229,9 +232,9 @@ public class ContactListFragment extends BaseFragment implements EventListener,
 						ContactId id = c.getId();
 						GroupCount count =
 								conversationManager.getGroupCount(id);
-						ConnectionStatus status = connectionRegistry
-								.getConnectionStatus(c.getId());
-						contacts.add(new ContactListItem(c, status, count));
+						boolean connected =
+								connectionRegistry.isConnected(c.getId());
+						contacts.add(new ContactListItem(c, connected, count));
 					} catch (NoSuchContactException e) {
 						// Continue
 					}
@@ -262,9 +265,10 @@ public class ContactListFragment extends BaseFragment implements EventListener,
 		if (e instanceof ContactAddedEvent) {
 			LOG.info("Contact added, reloading");
 			loadContacts();
-		} else if (e instanceof ConnectionStatusChangedEvent) {
-			ConnectionStatusChangedEvent c = (ConnectionStatusChangedEvent) e;
-			setConnectionStatus(c.getContactId(), c.getConnectionStatus());
+		} else if (e instanceof ContactConnectedEvent) {
+			setConnected(((ContactConnectedEvent) e).getContactId(), true);
+		} else if (e instanceof ContactDisconnectedEvent) {
+			setConnected(((ContactDisconnectedEvent) e).getContactId(), false);
 		} else if (e instanceof ContactRemovedEvent) {
 			LOG.info("Contact removed, removing item");
 			removeItem(((ContactRemovedEvent) e).getContactId());
@@ -300,12 +304,12 @@ public class ContactListFragment extends BaseFragment implements EventListener,
 	}
 
 	@UiThread
-	private void setConnectionStatus(ContactId c, ConnectionStatus status) {
+	private void setConnected(ContactId c, boolean connected) {
 		adapter.incrementRevision();
 		int position = adapter.findItemPosition(c);
 		ContactListItem item = adapter.getItemAt(position);
 		if (item != null) {
-			item.setConnectionStatus(status);
+			item.setConnected(connected);
 			adapter.updateItemAt(position, item);
 		}
 	}

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

@@ -2,7 +2,6 @@ package org.briarproject.briar.android.contact;
 
 import org.briarproject.bramble.api.contact.Contact;
 import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
-import org.briarproject.bramble.api.plugin.ConnectionStatus;
 import org.briarproject.briar.api.client.MessageTracker.GroupCount;
 import org.briarproject.briar.api.conversation.ConversationMessageHeader;
 
@@ -16,9 +15,9 @@ public class ContactListItem extends ContactItem {
 	private long timestamp;
 	private int unread;
 
-	public ContactListItem(Contact contact, ConnectionStatus status,
+	public ContactListItem(Contact contact, boolean connected,
 			GroupCount count) {
-		super(contact, status);
+		super(contact, connected);
 		this.empty = count.getMsgCount() == 0;
 		this.unread = count.getUnreadCount();
 		this.timestamp = count.getLatestMsgTime();

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

@@ -7,6 +7,7 @@ import org.briarproject.bramble.api.contact.ContactId;
 import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
 import org.briarproject.briar.R;
 import org.briarproject.briar.android.contact.BaseContactListAdapter.OnContactClickListener;
+import org.briarproject.briar.android.util.UiUtils;
 
 import java.util.Locale;
 
@@ -14,11 +15,8 @@ import javax.annotation.Nullable;
 
 import androidx.annotation.UiThread;
 
-import static android.view.View.INVISIBLE;
-import static android.view.View.VISIBLE;
 import static androidx.core.view.ViewCompat.setTransitionName;
 import static org.briarproject.briar.android.util.UiUtils.formatDate;
-import static org.briarproject.briar.android.util.UiUtils.getAvatarTransitionName;
 
 @UiThread
 @NotNullByDefault
@@ -41,11 +39,10 @@ class ContactListItemViewHolder extends ContactItemViewHolder<ContactListItem> {
 		// unread count
 		int unreadCount = item.getUnreadCount();
 		if (unreadCount > 0) {
-			unread.setText(String.format(Locale.getDefault(), "%d",
-					unreadCount));
-			unread.setVisibility(VISIBLE);
+			unread.setText(String.format(Locale.getDefault(), "%d", unreadCount));
+			unread.setVisibility(View.VISIBLE);
 		} else {
-			unread.setVisibility(INVISIBLE);
+			unread.setVisibility(View.INVISIBLE);
 		}
 
 		// date of last message
@@ -57,7 +54,8 @@ class ContactListItemViewHolder extends ContactItemViewHolder<ContactListItem> {
 		}
 
 		ContactId c = item.getContact().getId();
-		setTransitionName(avatar, getAvatarTransitionName(c));
+		setTransitionName(avatar, UiUtils.getAvatarTransitionName(c));
+		setTransitionName(bulb, UiUtils.getBulbTransitionName(c));
 	}
 
 }

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

@@ -3,7 +3,6 @@ package org.briarproject.briar.android.contact.add.remote;
 import android.content.Context;
 import android.content.DialogInterface.OnClickListener;
 import android.content.Intent;
-import android.graphics.drawable.Drawable;
 import android.os.Bundle;
 import android.text.Editable;
 import android.view.LayoutInflater;
@@ -38,12 +37,10 @@ import androidx.lifecycle.ViewModelProviders;
 import static android.view.View.INVISIBLE;
 import static android.view.View.VISIBLE;
 import static android.widget.Toast.LENGTH_LONG;
-import static androidx.core.content.ContextCompat.getColor;
-import static androidx.core.content.ContextCompat.getDrawable;
-import static androidx.core.graphics.drawable.DrawableCompat.setTint;
 import static java.util.Objects.requireNonNull;
 import static org.briarproject.bramble.api.identity.AuthorConstants.MAX_AUTHOR_NAME_LENGTH;
 import static org.briarproject.bramble.util.StringUtils.utf8IsTooLong;
+import static org.briarproject.briar.android.util.UiUtils.getDialogIcon;
 
 @MethodsNotNullByDefault
 @ParametersNotNullByDefault
@@ -199,9 +196,7 @@ public class NicknameFragment extends BaseFragment {
 	private void showWarningDialog(String name1, String name2) {
 		Context ctx = requireContext();
 		Builder b = new Builder(ctx, R.style.BriarDialogTheme);
-		Drawable icon = getDrawable(ctx, R.drawable.alerts_and_states_error);
-		setTint(requireNonNull(icon), getColor(ctx, R.color.color_primary));
-		b.setIcon(icon);
+		b.setIcon(getDialogIcon(ctx, R.drawable.alerts_and_states_error));
 		b.setTitle(getString(R.string.duplicate_link_dialog_title));
 		b.setMessage(
 				getString(R.string.duplicate_link_dialog_text_3, name1, name2));

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

@@ -6,7 +6,8 @@ import org.briarproject.bramble.api.event.EventBus;
 import org.briarproject.bramble.api.event.EventListener;
 import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
 import org.briarproject.bramble.api.plugin.ConnectionRegistry;
-import org.briarproject.bramble.api.plugin.event.ConnectionStatusChangedEvent;
+import org.briarproject.bramble.api.plugin.event.ContactConnectedEvent;
+import org.briarproject.bramble.api.plugin.event.ContactDisconnectedEvent;
 
 import java.util.Collection;
 import java.util.HashSet;
@@ -17,8 +18,6 @@ import javax.inject.Inject;
 
 import androidx.annotation.UiThread;
 
-import static org.briarproject.bramble.api.plugin.ConnectionStatus.CONNECTED;
-
 @NotNullByDefault
 public class SharingControllerImpl implements SharingController, EventListener {
 
@@ -61,14 +60,15 @@ public class SharingControllerImpl implements SharingController, EventListener {
 
 	@Override
 	public void eventOccurred(Event e) {
-		if (e instanceof ConnectionStatusChangedEvent) {
-			ConnectionStatusChangedEvent c = (ConnectionStatusChangedEvent) e;
-			setConnectionStatus(c.getContactId());
+		if (e instanceof ContactConnectedEvent) {
+			setConnected(((ContactConnectedEvent) e).getContactId());
+		} else if (e instanceof ContactDisconnectedEvent) {
+			setConnected(((ContactDisconnectedEvent) e).getContactId());
 		}
 	}
 
 	@UiThread
-	private void setConnectionStatus(ContactId c) {
+	private void setConnected(ContactId c) {
 		if (listener == null) throw new IllegalStateException();
 		if (contacts.contains(c)) {
 			int online = getOnlineCount();
@@ -95,9 +95,7 @@ public class SharingControllerImpl implements SharingController, EventListener {
 	public int getOnlineCount() {
 		int online = 0;
 		for (ContactId c : contacts) {
-			if (connectionRegistry.getConnectionStatus(c) == CONNECTED) {
-				online++;
-			}
+			if (connectionRegistry.isConnected(c)) online++;
 		}
 		return online;
 	}

briar-android/src/main/java/org/briarproject/briar/android/conversation/ConversationActivity.java

@@ -13,6 +13,7 @@ import android.view.Menu;
 import android.view.MenuInflater;
 import android.view.MenuItem;
 import android.view.View;
+import android.widget.ImageView;
 import android.widget.TextView;
 import android.widget.Toast;
 
@@ -33,8 +34,8 @@ import org.briarproject.bramble.api.event.EventListener;
 import org.briarproject.bramble.api.nullsafety.MethodsNotNullByDefault;
 import org.briarproject.bramble.api.nullsafety.ParametersNotNullByDefault;
 import org.briarproject.bramble.api.plugin.ConnectionRegistry;
-import org.briarproject.bramble.api.plugin.ConnectionStatus;
-import org.briarproject.bramble.api.plugin.event.ConnectionStatusChangedEvent;
+import org.briarproject.bramble.api.plugin.event.ContactConnectedEvent;
+import org.briarproject.bramble.api.plugin.event.ContactDisconnectedEvent;
 import org.briarproject.bramble.api.sync.ClientId;
 import org.briarproject.bramble.api.sync.MessageId;
 import org.briarproject.bramble.api.sync.event.MessagesAckedEvent;
@@ -124,8 +125,6 @@ import static java.util.Objects.requireNonNull;
 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.ConnectionStatus.CONNECTED;
-import static org.briarproject.bramble.api.plugin.ConnectionStatus.RECENTLY_CONNECTED;
 import static org.briarproject.bramble.util.LogUtils.logDuration;
 import static org.briarproject.bramble.util.LogUtils.logException;
 import static org.briarproject.bramble.util.LogUtils.now;
@@ -139,6 +138,7 @@ import static org.briarproject.briar.android.conversation.ImageActivity.ATTACHME
 import static org.briarproject.briar.android.conversation.ImageActivity.DATE;
 import static org.briarproject.briar.android.conversation.ImageActivity.NAME;
 import static org.briarproject.briar.android.util.UiUtils.getAvatarTransitionName;
+import static org.briarproject.briar.android.util.UiUtils.getBulbTransitionName;
 import static org.briarproject.briar.android.util.UiUtils.observeOnce;
 import static org.briarproject.briar.api.messaging.MessagingConstants.MAX_ATTACHMENTS_PER_MESSAGE;
 import static org.briarproject.briar.api.messaging.MessagingConstants.MAX_PRIVATE_MESSAGE_TEXT_LENGTH;
@@ -198,8 +198,8 @@ public class ConversationActivity extends BriarActivity
 	private ConversationAdapter adapter;
 	private Toolbar toolbar;
 	private CircleImageView toolbarAvatar;
+	private ImageView toolbarStatus;
 	private TextView toolbarTitle;
-	private TextView toolbarStatus;
 	private BriarRecyclerView list;
 	private LinearLayoutManager layoutManager;
 	private TextInputView textInputView;
@@ -237,8 +237,8 @@ public class ConversationActivity extends BriarActivity
 		// Custom Toolbar
 		toolbar = requireNonNull(setUpCustomToolbar(true));
 		toolbarAvatar = toolbar.findViewById(R.id.contactAvatar);
-		toolbarTitle = toolbar.findViewById(R.id.contactName);
 		toolbarStatus = toolbar.findViewById(R.id.contactStatus);
+		toolbarTitle = toolbar.findViewById(R.id.contactName);
 
 		observeOnce(viewModel.getContactAuthorId(), this, authorId -> {
 			requireNonNull(authorId);
@@ -257,6 +257,7 @@ public class ConversationActivity extends BriarActivity
 				this::onAddedPrivateMessage);
 
 		setTransitionName(toolbarAvatar, getAvatarTransitionName(contactId));
+		setTransitionName(toolbarStatus, getBulbTransitionName(contactId));
 
 		visitor = new ConversationVisitor(this, this, this,
 				viewModel.getContactDisplayName());
@@ -498,14 +499,14 @@ public class ConversationActivity extends BriarActivity
 
 	@UiThread
 	private void displayContactOnlineStatus() {
-		ConnectionStatus status =
-				connectionRegistry.getConnectionStatus(contactId);
-		if (status == CONNECTED) {
-			toolbarStatus.setText(R.string.online);
-		} else if (status == RECENTLY_CONNECTED) {
-			toolbarStatus.setText(R.string.recently_online);
+		if (connectionRegistry.isConnected(contactId)) {
+			toolbarStatus.setImageDrawable(ContextCompat.getDrawable(
+					ConversationActivity.this, R.drawable.contact_online));
+			toolbarStatus.setContentDescription(getString(R.string.online));
 		} else {
-			toolbarStatus.setText(R.string.offline);
+			toolbarStatus.setImageDrawable(ContextCompat.getDrawable(
+					ConversationActivity.this, R.drawable.contact_offline));
+			toolbarStatus.setContentDescription(getString(R.string.offline));
 		}
 	}
 
@@ -728,10 +729,16 @@ public class ConversationActivity extends BriarActivity
 				LOG.info("Messages acked");
 				markMessages(m.getMessageIds(), true, true);
 			}
-		} else if (e instanceof ConnectionStatusChangedEvent) {
-			ConnectionStatusChangedEvent c = (ConnectionStatusChangedEvent) e;
+		} else if (e instanceof ContactConnectedEvent) {
+			ContactConnectedEvent c = (ContactConnectedEvent) e;
 			if (c.getContactId().equals(contactId)) {
-				LOG.info("Connection status changed");
+				LOG.info("Contact connected");
+				displayContactOnlineStatus();
+			}
+		} else if (e instanceof ContactDisconnectedEvent) {
+			ContactDisconnectedEvent c = (ContactDisconnectedEvent) e;
+			if (c.getContactId().equals(contactId)) {
+				LOG.info("Contact disconnected");
 				displayContactOnlineStatus();
 			}
 		} else if (e instanceof ClientVersionUpdatedEvent) {

briar-android/src/main/java/org/briarproject/briar/android/conversation/ImageActivity.java

@@ -2,7 +2,6 @@ package org.briarproject.briar.android.conversation;
 
 import android.content.DialogInterface.OnClickListener;
 import android.content.Intent;
-import android.graphics.drawable.Drawable;
 import android.os.Bundle;
 import android.transition.Fade;
 import android.transition.Transition;
@@ -35,8 +34,6 @@ import androidx.annotation.Nullable;
 import androidx.annotation.RequiresApi;
 import androidx.appcompat.app.AlertDialog.Builder;
 import androidx.appcompat.widget.Toolbar;
-import androidx.core.content.ContextCompat;
-import androidx.core.graphics.drawable.DrawableCompat;
 import androidx.fragment.app.Fragment;
 import androidx.fragment.app.FragmentManager;
 import androidx.fragment.app.FragmentStatePagerAdapter;
@@ -59,6 +56,7 @@ import static com.google.android.material.snackbar.Snackbar.LENGTH_LONG;
 import static java.util.Objects.requireNonNull;
 import static org.briarproject.briar.android.activity.RequestCodes.REQUEST_SAVE_ATTACHMENT;
 import static org.briarproject.briar.android.util.UiUtils.formatDateAbsolute;
+import static org.briarproject.briar.android.util.UiUtils.getDialogIcon;
 
 @MethodsNotNullByDefault
 @ParametersNotNullByDefault
@@ -278,10 +276,7 @@ public class ImageActivity extends BriarActivity
 		Builder builder = new Builder(this, R.style.BriarDialogTheme);
 		builder.setTitle(getString(R.string.dialog_title_save_image));
 		builder.setMessage(getString(R.string.dialog_message_save_image));
-		Drawable icon = ContextCompat.getDrawable(this, R.drawable.ic_security);
-		DrawableCompat.setTint(requireNonNull(icon),
-				ContextCompat.getColor(this, R.color.color_primary));
-		builder.setIcon(icon);
+		builder.setIcon(getDialogIcon(this, R.drawable.ic_security));
 		builder.setPositiveButton(R.string.save_image, okListener);
 		builder.setNegativeButton(R.string.cancel, null);
 		builder.show();

briar-android/src/main/java/org/briarproject/briar/android/introduction/ContactChooserFragment.java

@@ -12,7 +12,6 @@ import org.briarproject.bramble.api.db.DbException;
 import org.briarproject.bramble.api.nullsafety.MethodsNotNullByDefault;
 import org.briarproject.bramble.api.nullsafety.ParametersNotNullByDefault;
 import org.briarproject.bramble.api.plugin.ConnectionRegistry;
-import org.briarproject.bramble.api.plugin.ConnectionStatus;
 import org.briarproject.briar.R;
 import org.briarproject.briar.android.activity.ActivityComponent;
 import org.briarproject.briar.android.contact.BaseContactListAdapter.OnContactClickListener;
@@ -74,8 +73,7 @@ public class ContactChooserFragment extends BaseFragment {
 	}
 
 	@Override
-	public View onCreateView(LayoutInflater inflater,
-			@Nullable ViewGroup container,
+	public View onCreateView(LayoutInflater inflater, @Nullable ViewGroup container,
 			@Nullable Bundle savedInstanceState) {
 
 		View contentView = inflater.inflate(R.layout.list, container, false);
@@ -129,9 +127,9 @@ public class ContactChooserFragment extends BaseFragment {
 						ContactId id = c.getId();
 						GroupCount count =
 								conversationManager.getGroupCount(id);
-						ConnectionStatus status = connectionRegistry
-								.getConnectionStatus(c.getId());
-						contacts.add(new ContactListItem(c, status, count));
+						boolean connected =
+								connectionRegistry.isConnected(c.getId());
+						contacts.add(new ContactListItem(c, connected, count));
 					}
 				}
 				displayContacts(contacts);

briar-android/src/main/java/org/briarproject/briar/android/keyagreement/ContactExchangeActivity.java

@@ -9,6 +9,7 @@ import org.briarproject.bramble.api.nullsafety.MethodsNotNullByDefault;
 import org.briarproject.bramble.api.nullsafety.ParametersNotNullByDefault;
 import org.briarproject.briar.R;
 import org.briarproject.briar.android.activity.ActivityComponent;
+import org.briarproject.briar.android.fragment.BaseFragment;
 
 import javax.annotation.Nullable;
 import javax.inject.Inject;
@@ -79,13 +80,13 @@ public class ContactExchangeActivity extends KeyAgreementActivity {
 
 	@UiThread
 	private void contactExchangeFailed() {
-		showErrorFragment(R.string.connection_error_explanation);
+		showErrorFragment();
 	}
 
 	@UiThread
 	@Override
 	public void keyAgreementFailed() {
-		showErrorFragment(R.string.connection_error_explanation);
+		showErrorFragment();
 	}
 
 	@UiThread
@@ -103,7 +104,7 @@ public class ContactExchangeActivity extends KeyAgreementActivity {
 	@UiThread
 	@Override
 	public void keyAgreementAborted(boolean remoteAborted) {
-		showErrorFragment(R.string.connection_error_explanation);
+		showErrorFragment();
 	}
 
 	@UiThread
@@ -112,4 +113,10 @@ public class ContactExchangeActivity extends KeyAgreementActivity {
 		startContactExchange(result);
 		return getString(R.string.exchanging_contact_details);
 	}
+
+	protected void showErrorFragment() {
+		String errorMsg = getString(R.string.connection_error_explanation);
+		BaseFragment f = ContactExchangeErrorFragment.newInstance(errorMsg);
+		showNextFragment(f);
+	}
 }

briar-android/src/main/java/org/briarproject/briar/android/keyagreement/KeyAgreementActivity.java

@@ -8,10 +8,18 @@ import android.content.IntentFilter;
 import android.os.Bundle;
 import android.view.MenuItem;
 
+import org.briarproject.bramble.api.event.Event;
 import org.briarproject.bramble.api.event.EventBus;
+import org.briarproject.bramble.api.event.EventListener;
 import org.briarproject.bramble.api.nullsafety.MethodsNotNullByDefault;
 import org.briarproject.bramble.api.nullsafety.ParametersNotNullByDefault;
+import org.briarproject.bramble.api.plugin.BluetoothConstants;
+import org.briarproject.bramble.api.plugin.LanTcpConstants;
+import org.briarproject.bramble.api.plugin.Plugin;
+import org.briarproject.bramble.api.plugin.Plugin.State;
+import org.briarproject.bramble.api.plugin.PluginManager;
 import org.briarproject.bramble.api.plugin.event.BluetoothEnabledEvent;
+import org.briarproject.bramble.api.plugin.event.TransportStateEvent;
 import org.briarproject.briar.R;
 import org.briarproject.briar.android.activity.ActivityComponent;
 import org.briarproject.briar.android.activity.BriarActivity;
@@ -37,13 +45,15 @@ import static android.Manifest.permission.ACCESS_COARSE_LOCATION;
 import static android.Manifest.permission.CAMERA;
 import static android.bluetooth.BluetoothAdapter.ACTION_REQUEST_DISCOVERABLE;
 import static android.bluetooth.BluetoothAdapter.ACTION_SCAN_MODE_CHANGED;
-import static android.bluetooth.BluetoothAdapter.ACTION_STATE_CHANGED;
-import static android.bluetooth.BluetoothAdapter.EXTRA_SCAN_MODE;
-import static android.bluetooth.BluetoothAdapter.EXTRA_STATE;
-import static android.bluetooth.BluetoothAdapter.SCAN_MODE_CONNECTABLE;
 import static android.bluetooth.BluetoothAdapter.SCAN_MODE_CONNECTABLE_DISCOVERABLE;
-import static android.bluetooth.BluetoothAdapter.STATE_ON;
 import static android.content.pm.PackageManager.PERMISSION_GRANTED;
+import static java.util.logging.Level.INFO;
+import static java.util.logging.Logger.getLogger;
+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.INACTIVE;
+import static org.briarproject.bramble.api.plugin.Plugin.State.STARTING_STOPPING;
 import static org.briarproject.briar.android.activity.RequestCodes.REQUEST_BLUETOOTH_DISCOVERABLE;
 import static org.briarproject.briar.android.activity.RequestCodes.REQUEST_PERMISSION_CAMERA_LOCATION;
 
@@ -51,10 +61,33 @@ import static org.briarproject.briar.android.activity.RequestCodes.REQUEST_PERMI
 @ParametersNotNullByDefault
 public abstract class KeyAgreementActivity extends BriarActivity implements
 		BaseFragmentListener, IntroScreenSeenListener,
-		KeyAgreementEventListener {
+		KeyAgreementEventListener, EventListener {
 
-	private enum BluetoothState {
-		UNKNOWN, NO_ADAPTER, WAITING, REFUSED, ENABLED, DISCOVERABLE
+	private enum BluetoothDecision {
+		/**
+		 * We haven't asked the user about Bluetooth discoverability.
+		 */
+		UNKNOWN,
+
+		/**
+		 * The device doesn't have a Bluetooth adapter.
+		 */
+		NO_ADAPTER,
+
+		/**
+		 * We're waiting for the user to accept or refuse discoverability.
+		 */
+		WAITING,
+
+		/**
+		 * The user has accepted discoverability.
+		 */
+		ACCEPTED,
+
+		/**
+		 * The user has refused discoverability.
+		 */
+		REFUSED
 	}
 
 	private enum Permission {
@@ -62,11 +95,14 @@ public abstract class KeyAgreementActivity extends BriarActivity implements
 	}
 
 	private static final Logger LOG =
-			Logger.getLogger(KeyAgreementActivity.class.getName());
+			getLogger(KeyAgreementActivity.class.getName());
 
 	@Inject
 	EventBus eventBus;
 
+	@Inject
+	PluginManager pluginManager;
+
 	/**
 	 * Set to true in onPostResume() and false in onPause(). This prevents the
 	 * QR code fragment from being shown if onRequestPermissionsResult() is
@@ -74,21 +110,36 @@ public abstract class KeyAgreementActivity extends BriarActivity implements
 	 * https://issuetracker.google.com/issues/37067655.
 	 */
 	private boolean isResumed = false;
+
 	/**
 	 * Set to true when the continue button is clicked, and false when the QR
 	 * code fragment is shown. This prevents the QR code fragment from being
 	 * shown automatically before the continue button has been clicked.
 	 */
 	private boolean continueClicked = false;
+
 	/**
 	 * Records whether the Bluetooth adapter was already enabled before we
 	 * asked for Bluetooth discoverability, so we know whether to broadcast a
 	 * {@link BluetoothEnabledEvent}.
 	 */
 	private boolean wasAdapterEnabled = false;
+
+	/**
+	 * Records whether we've enabled the wifi plugin so we don't enable it more
+	 * than once.
+	 */
+	private boolean hasEnabledWifi = false;
+
+	/**
+	 * Records whether we've enabled the Bluetooth plugin so we don't enable it
+	 * more than once.
+	 */
+	private boolean hasEnabledBluetooth = false;
+
 	private Permission cameraPermission = Permission.UNKNOWN;
 	private Permission locationPermission = Permission.UNKNOWN;
-	private BluetoothState bluetoothState = BluetoothState.UNKNOWN;
+	private BluetoothDecision bluetoothDecision = BluetoothDecision.UNKNOWN;
 	private BroadcastReceiver bluetoothReceiver = null;
 
 	@Override
@@ -96,20 +147,17 @@ public abstract class KeyAgreementActivity extends BriarActivity implements
 		component.inject(this);
 	}
 
-	@SuppressWarnings("ConstantConditions")
 	@Override
 	public void onCreate(@Nullable Bundle state) {
 		super.onCreate(state);
 		setContentView(R.layout.activity_fragment_container_toolbar);
 		Toolbar toolbar = findViewById(R.id.toolbar);
 		setSupportActionBar(toolbar);
-		getSupportActionBar().setDisplayHomeAsUpEnabled(true);
+		requireNonNull(getSupportActionBar()).setDisplayHomeAsUpEnabled(true);
 		if (state == null) {
 			showInitialFragment(IntroFragment.newInstance());
 		}
-		IntentFilter filter = new IntentFilter();
-		filter.addAction(ACTION_STATE_CHANGED);
-		filter.addAction(ACTION_SCAN_MODE_CHANGED);
+		IntentFilter filter = new IntentFilter(ACTION_SCAN_MODE_CHANGED);
 		bluetoothReceiver = new BluetoothStateReceiver();
 		registerReceiver(bluetoothReceiver, filter);
 	}
@@ -122,18 +170,17 @@ public abstract class KeyAgreementActivity extends BriarActivity implements
 
 	@Override
 	public boolean onOptionsItemSelected(MenuItem item) {
-		switch (item.getItemId()) {
-			case android.R.id.home:
-				onBackPressed();
-				return true;
-			default:
-				return super.onOptionsItemSelected(item);
+		if (item.getItemId() == android.R.id.home) {
+			onBackPressed();
+			return true;
 		}
+		return super.onOptionsItemSelected(item);
 	}
 
 	@Override
 	public void onStart() {
 		super.onStart();
+		eventBus.addListener(this);
 		// Permissions may have been granted manually while we were stopped
 		cameraPermission = Permission.UNKNOWN;
 		locationPermission = Permission.UNKNOWN;
@@ -150,11 +197,22 @@ public abstract class KeyAgreementActivity extends BriarActivity implements
 
 	private void showQrCodeFragmentIfAllowed() {
 		if (isResumed && continueClicked && areEssentialPermissionsGranted()) {
-			if (bluetoothState == BluetoothState.UNKNOWN ||
-					bluetoothState == BluetoothState.ENABLED) {
-				requestBluetoothDiscoverable();
-			} else if (bluetoothState != BluetoothState.WAITING) {
+			if (isWifiReady() && isBluetoothReady()) {
+				LOG.info("Wifi and Bluetooth are ready");
 				showQrCodeFragment();
+			} else {
+				if (shouldEnableWifi()) {
+					LOG.info("Enabling wifi plugin");
+					hasEnabledWifi = true;
+					pluginManager.setPluginEnabled(LanTcpConstants.ID, true);
+				}
+				if (bluetoothDecision == BluetoothDecision.UNKNOWN) {
+					requestBluetoothDiscoverable();
+				} else if (shouldEnableBluetooth()) {
+					LOG.info("Enabling Bluetooth plugin");
+					hasEnabledBluetooth = true;
+					pluginManager.setPluginEnabled(BluetoothConstants.ID, true);
+				}
 			}
 		}
 	}
@@ -167,57 +225,108 @@ public abstract class KeyAgreementActivity extends BriarActivity implements
 						locationPermission == Permission.PERMANENTLY_DENIED);
 	}
 
+	private boolean isWifiReady() {
+		Plugin p = pluginManager.getPlugin(LanTcpConstants.ID);
+		if (p == null) return true; // Continue without wifi
+		State state = p.getState();
+		// Wait for plugin to become enabled
+		return state == ACTIVE || state == INACTIVE;
+	}
+
+	private boolean isBluetoothReady() {
+		if (bluetoothDecision == BluetoothDecision.UNKNOWN ||
+				bluetoothDecision == BluetoothDecision.WAITING) {
+			// Wait for decision
+			return false;
+		}
+		if (bluetoothDecision == BluetoothDecision.NO_ADAPTER
+				|| bluetoothDecision == BluetoothDecision.REFUSED) {
+			// Continue without Bluetooth
+			return true;
+		}
+		BluetoothAdapter bt = BluetoothAdapter.getDefaultAdapter();
+		if (bt == null) return true; // Continue without Bluetooth
+		if (bt.getScanMode() != SCAN_MODE_CONNECTABLE_DISCOVERABLE) {
+			// Wait for adapter to become discoverable
+			return false;
+		}
+		Plugin p = pluginManager.getPlugin(BluetoothConstants.ID);
+		if (p == null) return true; // Continue without Bluetooth
+		// Wait for plugin to become active
+		return p.getState() == ACTIVE;
+	}
+
+	private boolean shouldEnableWifi() {
+		if (hasEnabledWifi) return false;
+		Plugin p = pluginManager.getPlugin(LanTcpConstants.ID);
+		if (p == null) return false;
+		State state = p.getState();
+		return state == STARTING_STOPPING || state == DISABLED;
+	}
+
+	private void requestBluetoothDiscoverable() {
+		BluetoothAdapter bt = BluetoothAdapter.getDefaultAdapter();
+		if (bt == null) {
+			bluetoothDecision = BluetoothDecision.NO_ADAPTER;
+			showQrCodeFragmentIfAllowed();
+		} else {
+			Intent i = new Intent(ACTION_REQUEST_DISCOVERABLE);
+			if (i.resolveActivity(getPackageManager()) != null) {
+				LOG.info("Asking for Bluetooth discoverability");
+				bluetoothDecision = BluetoothDecision.WAITING;
+				wasAdapterEnabled = bt.isEnabled();
+				startActivityForResult(i, REQUEST_BLUETOOTH_DISCOVERABLE);
+			} else {
+				bluetoothDecision = BluetoothDecision.NO_ADAPTER;
+				showQrCodeFragmentIfAllowed();
+			}
+		}
+	}
+
+	private boolean shouldEnableBluetooth() {
+		if (bluetoothDecision != BluetoothDecision.ACCEPTED) return false;
+		if (hasEnabledBluetooth) return false;
+		Plugin p = pluginManager.getPlugin(BluetoothConstants.ID);
+		if (p == null) return false;
+		State state = p.getState();
+		return state == STARTING_STOPPING || state == DISABLED;
+	}
+
 	@Override
 	protected void onPause() {
 		super.onPause();
 		isResumed = false;
 	}
 
+	@Override
+	protected void onStop() {
+		super.onStop();
+		eventBus.removeListener(this);
+	}
+
 	@Override
 	public void showNextScreen() {
 		continueClicked = true;
 		if (checkPermissions()) showQrCodeFragmentIfAllowed();
 	}
 
-	private void requestBluetoothDiscoverable() {
-		BluetoothAdapter bt = BluetoothAdapter.getDefaultAdapter();
-		if (bt == null) {
-			setBluetoothState(BluetoothState.NO_ADAPTER);
-		} else {
-			Intent i = new Intent(ACTION_REQUEST_DISCOVERABLE);
-			if (i.resolveActivity(getPackageManager()) != null) {
-				setBluetoothState(BluetoothState.WAITING);
-				wasAdapterEnabled = bt.isEnabled();
-				startActivityForResult(i, REQUEST_BLUETOOTH_DISCOVERABLE);
-			} else {
-				setBluetoothState(BluetoothState.NO_ADAPTER);
-			}
-		}
-	}
-
-	private void setBluetoothState(BluetoothState bluetoothState) {
-		LOG.info("Setting Bluetooth state to " + bluetoothState);
-		this.bluetoothState = bluetoothState;
-		if (!wasAdapterEnabled && bluetoothState == BluetoothState.ENABLED) {
-			eventBus.broadcast(new BluetoothEnabledEvent());
-			wasAdapterEnabled = true;
-		}
-		showQrCodeFragmentIfAllowed();
-	}
-
 	@Override
-	public void onActivityResult(int request, int result, Intent data) {
+	public void onActivityResult(int request, int result,
+			@Nullable Intent data) {
 		if (request == REQUEST_BLUETOOTH_DISCOVERABLE) {
 			if (result == RESULT_CANCELED) {
-				setBluetoothState(BluetoothState.REFUSED);
+				LOG.info("Bluetooth discoverability was refused");
+				bluetoothDecision = BluetoothDecision.REFUSED;
 			} else {
-				// If Bluetooth is already discoverable, show the QR code -
-				// otherwise wait for the state or scan mode to change
-				BluetoothAdapter bt = BluetoothAdapter.getDefaultAdapter();
-				if (bt == null) throw new AssertionError();
-				if (bt.getScanMode() == SCAN_MODE_CONNECTABLE_DISCOVERABLE)
-					setBluetoothState(BluetoothState.DISCOVERABLE);
+				LOG.info("Bluetooth discoverability was accepted");
+				bluetoothDecision = BluetoothDecision.ACCEPTED;
+				if (!wasAdapterEnabled) {
+					LOG.info("Bluetooth adapter was enabled by us");
+					eventBus.broadcast(new BluetoothEnabledEvent());
+					wasAdapterEnabled = true;
+				}
 			}
+			showQrCodeFragmentIfAllowed();
 		} else super.onActivityResult(request, result, data);
 	}
 
@@ -227,7 +336,12 @@ public abstract class KeyAgreementActivity extends BriarActivity implements
 		continueClicked = false;
 		// If we return to the intro fragment, ask for Bluetooth
 		// discoverability again before showing the QR code fragment
-		bluetoothState = BluetoothState.UNKNOWN;
+		bluetoothDecision = BluetoothDecision.UNKNOWN;
+		// If we return to the intro fragment, we may need to enable wifi and
+		// Bluetooth again
+		hasEnabledWifi = false;
+		hasEnabledBluetooth = false;
+
 		// FIXME #824
 		FragmentManager fm = getSupportFragmentManager();
 		if (fm.findFragmentByTag(KeyAgreementFragment.TAG) == null) {
@@ -239,12 +353,6 @@ public abstract class KeyAgreementActivity extends BriarActivity implements
 		}
 	}
 
-	protected void showErrorFragment(@StringRes int errorResId) {
-		String errorMsg = getString(errorResId);
-		BaseFragment f = ContactExchangeErrorFragment.newInstance(errorMsg);
-		showNextFragment(f);
-	}
-
 	private boolean checkPermissions() {
 		if (areEssentialPermissionsGranted()) return true;
 		// If the camera permission has been permanently denied, ask the
@@ -335,24 +443,30 @@ public abstract class KeyAgreementActivity extends BriarActivity implements
 				permission);
 	}
 
+	@Override
+	public void eventOccurred(Event e) {
+		if (e instanceof TransportStateEvent) {
+			TransportStateEvent t = (TransportStateEvent) e;
+			if (t.getTransportId().equals(BluetoothConstants.ID)) {
+				if (LOG.isLoggable(INFO)) {
+					LOG.info("Bluetooth state changed to " + t.getState());
+				}
+				showQrCodeFragmentIfAllowed();
+			} else if (t.getTransportId().equals(LanTcpConstants.ID)) {
+				if (LOG.isLoggable(INFO)) {
+					LOG.info("Wifi state changed to " + t.getState());
+				}
+				showQrCodeFragmentIfAllowed();
+			}
+		}
+	}
+
 	private class BluetoothStateReceiver extends BroadcastReceiver {
 
 		@Override
 		public void onReceive(Context context, Intent intent) {
-			String action = intent.getAction();
-			if (ACTION_STATE_CHANGED.equals(action)) {
-				int state = intent.getIntExtra(EXTRA_STATE, 0);
-				if (state == STATE_ON)
-					setBluetoothState(BluetoothState.ENABLED);
-				else setBluetoothState(BluetoothState.UNKNOWN);
-			} else if (ACTION_SCAN_MODE_CHANGED.equals(action)) {
-				int scanMode = intent.getIntExtra(EXTRA_SCAN_MODE, 0);
-				if (scanMode == SCAN_MODE_CONNECTABLE_DISCOVERABLE)
-					setBluetoothState(BluetoothState.DISCOVERABLE);
-				else if (scanMode == SCAN_MODE_CONNECTABLE)
-					setBluetoothState(BluetoothState.ENABLED);
-				else setBluetoothState(BluetoothState.UNKNOWN);
-			}
+			LOG.info("Bluetooth scan mode changed");
+			showQrCodeFragmentIfAllowed();
 		}
 	}
 }

briar-android/src/main/java/org/briarproject/briar/android/login/ChangePasswordActivity.java

@@ -15,33 +15,27 @@ import android.widget.Toast;
 
 import com.google.android.material.textfield.TextInputLayout;
 
-import org.briarproject.bramble.api.crypto.DecryptionResult;
 import org.briarproject.briar.R;
 import org.briarproject.briar.android.activity.ActivityComponent;
 import org.briarproject.briar.android.activity.BriarActivity;
+import org.briarproject.briar.android.controller.handler.UiResultHandler;
+import org.briarproject.briar.android.util.UiUtils;
 
 import javax.inject.Inject;
 
-import androidx.annotation.VisibleForTesting;
-import androidx.lifecycle.ViewModelProvider;
-import androidx.lifecycle.ViewModelProviders;
+import androidx.annotation.NonNull;
 
 import static android.view.View.INVISIBLE;
 import static android.view.View.VISIBLE;
-import static android.widget.Toast.LENGTH_LONG;
-import static org.briarproject.bramble.api.crypto.DecryptionResult.KEY_STRENGTHENER_ERROR;
-import static org.briarproject.bramble.api.crypto.DecryptionResult.SUCCESS;
 import static org.briarproject.bramble.api.crypto.PasswordStrengthEstimator.QUITE_WEAK;
-import static org.briarproject.briar.android.login.LoginUtils.createKeyStrengthenerErrorDialog;
 import static org.briarproject.briar.android.util.UiUtils.hideSoftKeyboard;
-import static org.briarproject.briar.android.util.UiUtils.setError;
 import static org.briarproject.briar.android.util.UiUtils.showSoftKeyboard;
 
 public class ChangePasswordActivity extends BriarActivity
 		implements OnClickListener, OnEditorActionListener {
 
 	@Inject
-	ViewModelProvider.Factory viewModelFactory;
+	protected ChangePasswordController passwordController;
 
 	private TextInputLayout currentPasswordEntryWrapper;
 	private TextInputLayout newPasswordEntryWrapper;
@@ -53,17 +47,11 @@ public class ChangePasswordActivity extends BriarActivity
 	private Button changePasswordButton;
 	private ProgressBar progress;
 
-	@VisibleForTesting
-	ChangePasswordViewModel viewModel;
-
 	@Override
 	public void onCreate(Bundle state) {
 		super.onCreate(state);
 		setContentView(R.layout.activity_change_password);
 
-		viewModel = ViewModelProviders.of(this, viewModelFactory)
-				.get(ChangePasswordViewModel.class);
-
 		currentPasswordEntryWrapper =
 				findViewById(R.id.current_password_entry_wrapper);
 		newPasswordEntryWrapper = findViewById(R.id.new_password_entry_wrapper);
@@ -114,12 +102,13 @@ public class ChangePasswordActivity extends BriarActivity
 		String firstPassword = newPassword.getText().toString();
 		String secondPassword = newPasswordConfirmation.getText().toString();
 		boolean passwordsMatch = firstPassword.equals(secondPassword);
-		float strength = viewModel.estimatePasswordStrength(firstPassword);
+		float strength =
+				passwordController.estimatePasswordStrength(firstPassword);
 		strengthMeter.setStrength(strength);
-		setError(newPasswordEntryWrapper,
+		UiUtils.setError(newPasswordEntryWrapper,
 				getString(R.string.password_too_weak),
 				firstPassword.length() > 0 && strength < QUITE_WEAK);
-		setError(newPasswordConfirmationWrapper,
+		UiUtils.setError(newPasswordConfirmationWrapper,
 				getString(R.string.passwords_do_not_match),
 				secondPassword.length() > 0 && !passwordsMatch);
 		changePasswordButton.setEnabled(
@@ -138,34 +127,32 @@ public class ChangePasswordActivity extends BriarActivity
 		// Replace the button with a progress bar
 		changePasswordButton.setVisibility(INVISIBLE);
 		progress.setVisibility(VISIBLE);
-
-		String curPwd = currentPassword.getText().toString();
-		String newPwd = newPassword.getText().toString();
-		viewModel.changePassword(curPwd, newPwd).observeEvent(this, result -> {
-					if (result == SUCCESS) {
-						Toast.makeText(ChangePasswordActivity.this,
-								R.string.password_changed,
-								LENGTH_LONG).show();
-						setResult(RESULT_OK);
-						supportFinishAfterTransition();
-					} else {
-						tryAgain(result);
+		passwordController.changePassword(currentPassword.getText().toString(),
+				newPassword.getText().toString(),
+				new UiResultHandler<Boolean>(this) {
+					@Override
+					public void onResultUi(@NonNull Boolean result) {
+						if (result) {
+							Toast.makeText(ChangePasswordActivity.this,
+									R.string.password_changed,
+									Toast.LENGTH_LONG).show();
+							setResult(RESULT_OK);
+							supportFinishAfterTransition();
+						} else {
+							tryAgain();
+						}
 					}
-				}
-		);
+				});
 	}
 
-	private void tryAgain(DecryptionResult result) {
+	private void tryAgain() {
+		UiUtils.setError(currentPasswordEntryWrapper,
+				getString(R.string.try_again), true);
 		changePasswordButton.setVisibility(VISIBLE);
 		progress.setVisibility(INVISIBLE);
-		if (result == KEY_STRENGTHENER_ERROR) {
-			createKeyStrengthenerErrorDialog(this).show();
-		} else {
-			setError(currentPasswordEntryWrapper,
-					getString(R.string.try_again), true);
-			currentPassword.setText("");
-			// show the keyboard again
-			showSoftKeyboard(currentPassword);
-		}
+		currentPassword.setText("");
+
+		// show the keyboard again
+		showSoftKeyboard(currentPassword);
 	}
 }

briar-android/src/main/java/org/briarproject/briar/android/login/ChangePasswordControllerImpl.java

@@ -0,0 +1,43 @@
+package org.briarproject.briar.android.login;
+
+import org.briarproject.bramble.api.account.AccountManager;
+import org.briarproject.bramble.api.crypto.PasswordStrengthEstimator;
+import org.briarproject.bramble.api.lifecycle.IoExecutor;
+import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
+import org.briarproject.briar.android.controller.handler.ResultHandler;
+
+import java.util.concurrent.Executor;
+
+import javax.inject.Inject;
+
+@NotNullByDefault
+public class ChangePasswordControllerImpl implements ChangePasswordController {
+
+	protected final AccountManager accountManager;
+	protected final Executor ioExecutor;
+	private final PasswordStrengthEstimator strengthEstimator;
+
+	@Inject
+	ChangePasswordControllerImpl(AccountManager accountManager,
+			@IoExecutor Executor ioExecutor,
+			PasswordStrengthEstimator strengthEstimator) {
+		this.accountManager = accountManager;
+		this.ioExecutor = ioExecutor;
+		this.strengthEstimator = strengthEstimator;
+	}
+
+	@Override
+	public float estimatePasswordStrength(String password) {
+		return strengthEstimator.estimateStrength(password);
+	}
+
+	@Override
+	public void changePassword(String oldPassword, String newPassword,
+			ResultHandler<Boolean> resultHandler) {
+		ioExecutor.execute(() -> {
+			boolean changed =
+					accountManager.changePassword(oldPassword, newPassword);
+			resultHandler.onResult(changed);
+		});
+	}
+}

briar-android/src/main/java/org/briarproject/briar/android/login/ChangePasswordViewModel.java

@@ -1,53 +0,0 @@
-package org.briarproject.briar.android.login;
-
-import org.briarproject.bramble.api.account.AccountManager;
-import org.briarproject.bramble.api.crypto.DecryptionException;
-import org.briarproject.bramble.api.crypto.DecryptionResult;
-import org.briarproject.bramble.api.crypto.PasswordStrengthEstimator;
-import org.briarproject.bramble.api.lifecycle.IoExecutor;
-import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
-import org.briarproject.briar.android.viewmodel.LiveEvent;
-import org.briarproject.briar.android.viewmodel.MutableLiveEvent;
-
-import java.util.concurrent.Executor;
-
-import javax.inject.Inject;
-
-import androidx.lifecycle.ViewModel;
-
-import static org.briarproject.bramble.api.crypto.DecryptionResult.SUCCESS;
-
-@NotNullByDefault
-public class ChangePasswordViewModel extends ViewModel {
-
-	private final AccountManager accountManager;
-	private final Executor ioExecutor;
-	private final PasswordStrengthEstimator strengthEstimator;
-
-	@Inject
-	ChangePasswordViewModel(AccountManager accountManager,
-			@IoExecutor Executor ioExecutor,
-			PasswordStrengthEstimator strengthEstimator) {
-		this.accountManager = accountManager;
-		this.ioExecutor = ioExecutor;
-		this.strengthEstimator = strengthEstimator;
-	}
-
-	float estimatePasswordStrength(String password) {
-		return strengthEstimator.estimateStrength(password);
-	}
-
-	LiveEvent<DecryptionResult> changePassword(String oldPassword,
-			String newPassword) {
-		MutableLiveEvent<DecryptionResult> result = new MutableLiveEvent<>();
-		ioExecutor.execute(() -> {
-			try {
-				accountManager.changePassword(oldPassword, newPassword);
-				result.postEvent(SUCCESS);
-			} catch (DecryptionException e) {
-				result.postEvent(e.getDecryptionResult());
-			}
-		});
-		return result;
-	}
-}

briar-android/src/main/java/org/briarproject/briar/android/login/LoginModule.java

@@ -1,23 +0,0 @@
-package org.briarproject.briar.android.login;
-
-import org.briarproject.briar.android.viewmodel.ViewModelKey;
-
-import androidx.lifecycle.ViewModel;
-import dagger.Binds;
-import dagger.Module;
-import dagger.multibindings.IntoMap;
-
-@Module
-public abstract class LoginModule {
-
-	@Binds
-	@IntoMap
-	@ViewModelKey(StartupViewModel.class)
-	abstract ViewModel bindStartupViewModel(StartupViewModel viewModel);
-
-	@Binds
-	@IntoMap
-	@ViewModelKey(ChangePasswordViewModel.class)
-	abstract ViewModel bindChangePasswordViewModel(
-			ChangePasswordViewModel viewModel);
-}

briar-android/src/main/java/org/briarproject/briar/android/login/LoginUtils.java

@@ -1,30 +0,0 @@
-package org.briarproject.briar.android.login;
-
-import android.content.Context;
-import android.graphics.drawable.Drawable;
-
-import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
-import org.briarproject.briar.R;
-
-import androidx.appcompat.app.AlertDialog;
-
-import static androidx.core.content.ContextCompat.getColor;
-import static androidx.core.content.ContextCompat.getDrawable;
-import static androidx.core.graphics.drawable.DrawableCompat.setTint;
-import static java.util.Objects.requireNonNull;
-
-@NotNullByDefault
-class LoginUtils {
-
-	static AlertDialog createKeyStrengthenerErrorDialog(Context ctx) {
-		AlertDialog.Builder builder =
-				new AlertDialog.Builder(ctx, R.style.BriarDialogTheme);
-		Drawable icon = getDrawable(ctx, R.drawable.alerts_and_states_error);
-		setTint(requireNonNull(icon), getColor(ctx, R.color.color_primary));
-		builder.setIcon(icon);
-		builder.setTitle(R.string.dialog_title_cannot_check_password);
-		builder.setMessage(R.string.dialog_message_cannot_check_password);
-		builder.setPositiveButton(R.string.ok, null);
-		return builder.create();
-	}
-}

briar-android/src/main/java/org/briarproject/briar/android/login/PasswordFragment.java

@@ -12,7 +12,6 @@ import android.widget.ProgressBar;
 import com.google.android.material.textfield.TextInputEditText;
 import com.google.android.material.textfield.TextInputLayout;
 
-import org.briarproject.bramble.api.crypto.DecryptionResult;
 import org.briarproject.bramble.api.nullsafety.MethodsNotNullByDefault;
 import org.briarproject.bramble.api.nullsafety.ParametersNotNullByDefault;
 import org.briarproject.briar.R;
@@ -29,9 +28,6 @@ import androidx.lifecycle.ViewModelProviders;
 import static android.view.View.INVISIBLE;
 import static android.view.View.VISIBLE;
 import static android.view.inputmethod.EditorInfo.IME_ACTION_DONE;
-import static org.briarproject.bramble.api.crypto.DecryptionResult.KEY_STRENGTHENER_ERROR;
-import static org.briarproject.bramble.api.crypto.DecryptionResult.SUCCESS;
-import static org.briarproject.briar.android.login.LoginUtils.createKeyStrengthenerErrorDialog;
 import static org.briarproject.briar.android.util.UiUtils.enterPressed;
 import static org.briarproject.briar.android.util.UiUtils.hideSoftKeyboard;
 import static org.briarproject.briar.android.util.UiUtils.setError;
@@ -62,13 +58,12 @@ public class PasswordFragment extends BaseFragment implements TextWatcher {
 			@Nullable ViewGroup container,
 			@Nullable Bundle savedInstanceState) {
 		View v = inflater.inflate(R.layout.fragment_password, container,
-				false);
+						false);
 
 		viewModel = ViewModelProviders.of(requireActivity(), viewModelFactory)
 				.get(StartupViewModel.class);
-
-		viewModel.getPasswordValidated().observeEvent(this, result -> {
-			if (result != SUCCESS) onPasswordInvalid(result);
+		viewModel.getPasswordValidated().observeEvent(this, valid -> {
+			if (!valid) onPasswordInvalid();
 		});
 
 		signInButton = v.findViewById(R.id.btn_sign_in);
@@ -112,20 +107,18 @@ public class PasswordFragment extends BaseFragment implements TextWatcher {
 		viewModel.validatePassword(password.getText().toString());
 	}
 
-	private void onPasswordInvalid(DecryptionResult result) {
+	private void onPasswordInvalid() {
+		setError(input, getString(R.string.try_again), true);
 		signInButton.setVisibility(VISIBLE);
 		progress.setVisibility(INVISIBLE);
-		if (result == KEY_STRENGTHENER_ERROR) {
-			createKeyStrengthenerErrorDialog(requireContext()).show();
-		} else {
-			setError(input, getString(R.string.try_again), true);
-			password.setText(null);
-			// show the keyboard again
-			showSoftKeyboard(password);
-		}
+		password.setText(null);
+
+		// show the keyboard again
+		showSoftKeyboard(password);
 	}
 
-	private void onForgottenPasswordClick() {
+	public void onForgottenPasswordClick() {
+		// TODO Encapsulate the dialog in a re-usable fragment
 		AlertDialog.Builder builder = new AlertDialog.Builder(requireContext(),
 				R.style.BriarDialogTheme);
 		builder.setTitle(R.string.dialog_title_lost_password);

briar-android/src/main/java/org/briarproject/briar/android/login/StartupViewModel.java

@@ -3,8 +3,6 @@ package org.briarproject.briar.android.login;
 import android.app.Application;
 
 import org.briarproject.bramble.api.account.AccountManager;
-import org.briarproject.bramble.api.crypto.DecryptionException;
-import org.briarproject.bramble.api.crypto.DecryptionResult;
 import org.briarproject.bramble.api.event.Event;
 import org.briarproject.bramble.api.event.EventBus;
 import org.briarproject.bramble.api.event.EventListener;
@@ -26,7 +24,6 @@ import androidx.lifecycle.AndroidViewModel;
 import androidx.lifecycle.LiveData;
 import androidx.lifecycle.MutableLiveData;
 
-import static org.briarproject.bramble.api.crypto.DecryptionResult.SUCCESS;
 import static org.briarproject.bramble.api.lifecycle.LifecycleManager.LifecycleState.COMPACTING_DATABASE;
 import static org.briarproject.bramble.api.lifecycle.LifecycleManager.LifecycleState.MIGRATING_DATABASE;
 import static org.briarproject.bramble.api.lifecycle.LifecycleManager.LifecycleState.STARTING_SERVICES;
@@ -49,7 +46,7 @@ public class StartupViewModel extends AndroidViewModel
 	@IoExecutor
 	private final Executor ioExecutor;
 
-	private final MutableLiveEvent<DecryptionResult> passwordValidated =
+	private final MutableLiveEvent<Boolean> passwordValidated =
 			new MutableLiveEvent<>();
 	private final MutableLiveEvent<Boolean> accountDeleted =
 			new MutableLiveEvent<>();
@@ -108,17 +105,13 @@ public class StartupViewModel extends AndroidViewModel
 
 	void validatePassword(String password) {
 		ioExecutor.execute(() -> {
-			try {
-				accountManager.signIn(password);
-				passwordValidated.postEvent(SUCCESS);
-				state.postValue(SIGNED_IN);
-			} catch (DecryptionException e) {
-				passwordValidated.postEvent(e.getDecryptionResult());
-			}
+			boolean signedIn = accountManager.signIn(password);
+			passwordValidated.postEvent(signedIn);
+			if (signedIn) state.postValue(SIGNED_IN);
 		});
 	}
 
-	LiveEvent<DecryptionResult> getPasswordValidated() {
+	LiveEvent<Boolean> getPasswordValidated() {
 		return passwordValidated;
 	}
 

briar-android/src/main/java/org/briarproject/briar/android/navdrawer/NavDrawerActivity.java

@@ -1,16 +1,12 @@
 package org.briarproject.briar.android.navdrawer;
 
-import android.annotation.SuppressLint;
 import android.content.Intent;
 import android.content.res.Configuration;
 import android.net.Uri;
 import android.os.Bundle;
-import android.view.LayoutInflater;
 import android.view.MenuItem;
 import android.view.View;
 import android.view.ViewGroup;
-import android.widget.BaseAdapter;
-import android.widget.GridView;
 import android.widget.ImageView;
 import android.widget.TextView;
 
@@ -21,16 +17,11 @@ import org.briarproject.bramble.api.db.DbException;
 import org.briarproject.bramble.api.lifecycle.LifecycleManager;
 import org.briarproject.bramble.api.nullsafety.MethodsNotNullByDefault;
 import org.briarproject.bramble.api.nullsafety.ParametersNotNullByDefault;
-import org.briarproject.bramble.api.plugin.BluetoothConstants;
-import org.briarproject.bramble.api.plugin.LanTcpConstants;
-import org.briarproject.bramble.api.plugin.TorConstants;
-import org.briarproject.bramble.api.plugin.TransportId;
 import org.briarproject.briar.R;
 import org.briarproject.briar.android.activity.ActivityComponent;
 import org.briarproject.briar.android.activity.BriarActivity;
 import org.briarproject.briar.android.blog.FeedFragment;
 import org.briarproject.briar.android.contact.ContactListFragment;
-import org.briarproject.briar.android.controller.handler.UiResultHandler;
 import org.briarproject.briar.android.forum.ForumListFragment;
 import org.briarproject.briar.android.fragment.BaseFragment;
 import org.briarproject.briar.android.fragment.BaseFragment.BaseFragmentListener;
@@ -38,23 +29,21 @@ import org.briarproject.briar.android.logout.SignOutFragment;
 import org.briarproject.briar.android.privategroup.list.GroupListFragment;
 import org.briarproject.briar.android.settings.SettingsActivity;
 
-import java.util.ArrayList;
-import java.util.List;
 import java.util.logging.Logger;
 
 import javax.inject.Inject;
 
 import androidx.annotation.NonNull;
 import androidx.annotation.Nullable;
-import androidx.annotation.UiThread;
 import androidx.appcompat.app.ActionBar;
 import androidx.appcompat.app.ActionBarDrawerToggle;
 import androidx.appcompat.widget.Toolbar;
 import androidx.core.app.ActivityCompat;
-import androidx.core.content.ContextCompat;
 import androidx.drawerlayout.widget.DrawerLayout;
 import androidx.fragment.app.FragmentManager;
 import androidx.fragment.app.FragmentTransaction;
+import androidx.lifecycle.ViewModelProvider;
+import androidx.lifecycle.ViewModelProviders;
 
 import static android.view.View.GONE;
 import static android.view.View.VISIBLE;
@@ -72,8 +61,7 @@ import static org.briarproject.briar.android.util.UiUtils.getDaysUntilExpiry;
 @MethodsNotNullByDefault
 @ParametersNotNullByDefault
 public class NavDrawerActivity extends BriarActivity implements
-		BaseFragmentListener, TransportStateListener,
-		OnNavigationItemSelectedListener {
+		BaseFragmentListener, OnNavigationItemSelectedListener {
 
 	private static final Logger LOG =
 			getLogger(NavDrawerActivity.class.getName());
@@ -91,19 +79,18 @@ public class NavDrawerActivity extends BriarActivity implements
 	public static Uri SIGN_OUT_URI =
 			Uri.parse("briar-content://org.briarproject.briar/sign-out");
 
+	private NavDrawerViewModel viewModel;
 	private ActionBarDrawerToggle drawerToggle;
 
 	@Inject
-	NavDrawerController controller;
+	ViewModelProvider.Factory viewModelFactory;
+
 	@Inject
 	LifecycleManager lifecycleManager;
 
 	private DrawerLayout drawerLayout;
 	private NavigationView navigation;
 
-	private List<Transport> transports;
-	private BaseAdapter transportsAdapter;
-
 	@Override
 	public void injectActivity(ActivityComponent component) {
 		component.inject(this);
@@ -115,10 +102,20 @@ public class NavDrawerActivity extends BriarActivity implements
 		exitIfStartupFailed(getIntent());
 		setContentView(R.layout.activity_nav_drawer);
 
+		viewModel = ViewModelProviders.of(this, viewModelFactory)
+				.get(NavDrawerViewModel.class);
+
+		viewModel.showExpiryWarning().observe(this, this::showExpiryWarning);
+		viewModel.shouldAskForDozeWhitelisting().observe(this, ask -> {
+			if (ask) showDozeDialog(getString(R.string.setup_doze_intro));
+		});
+
+		View drawerScrollView = findViewById(R.id.drawerScrollView);
+		new PluginViewController(drawerScrollView, this, viewModel);
+
 		Toolbar toolbar = findViewById(R.id.toolbar);
 		drawerLayout = findViewById(R.id.drawer_layout);
 		navigation = findViewById(R.id.navigation);
-		GridView transportsView = findViewById(R.id.transportsView);
 
 		setSupportActionBar(toolbar);
 		ActionBar actionBar = requireNonNull(getSupportActionBar());
@@ -131,9 +128,6 @@ public class NavDrawerActivity extends BriarActivity implements
 		drawerLayout.addDrawerListener(drawerToggle);
 		navigation.setNavigationItemSelectedListener(this);
 
-		initializeTransports(getLayoutInflater());
-		transportsView.setAdapter(transportsAdapter);
-
 		lockManager.isLockable().observe(this, this::setLockVisible);
 
 		if (lifecycleManager.getLifecycleState().isAfter(RUNNING)) {
@@ -149,17 +143,10 @@ public class NavDrawerActivity extends BriarActivity implements
 	}
 
 	@Override
-	@SuppressLint("NewApi")
 	public void onStart() {
 		super.onStart();
-		updateTransports();
 		lockManager.checkIfLockable();
-		controller.showExpiryWarning(new UiResultHandler<Boolean>(this) {
-			@Override
-			public void onResultUi(Boolean expiry) {
-				if (expiry) showExpiryWarning();
-			}
-		});
+		viewModel.checkExpiryWarning();
 	}
 
 	@Override
@@ -167,16 +154,7 @@ public class NavDrawerActivity extends BriarActivity implements
 			@Nullable Intent data) {
 		super.onActivityResult(request, result, data);
 		if (request == REQUEST_PASSWORD && result == RESULT_OK) {
-			controller.shouldAskForDozeWhitelisting(this,
-					new UiResultHandler<Boolean>(this) {
-						@Override
-						public void onResultUi(Boolean ask) {
-							if (ask) {
-								showDozeDialog(
-										getString(R.string.setup_doze_intro));
-							}
-						}
-					});
+			viewModel.checkDozeWhitelisting();
 		}
 	}
 
@@ -346,134 +324,30 @@ public class NavDrawerActivity extends BriarActivity implements
 		if (item != null) item.setVisible(visible);
 	}
 
-	private void showExpiryWarning() {
+	private void showExpiryWarning(boolean show) {
 		int daysUntilExpiry = getDaysUntilExpiry();
-		if (daysUntilExpiry < 0) signOut();
+		if (daysUntilExpiry < 0) {
+			signOut();
+			return;
+		}
 
-		// show expiry warning text
 		ViewGroup expiryWarning = findViewById(R.id.expiryWarning);
-		TextView expiryWarningText =
-				expiryWarning.findViewById(R.id.expiryWarningText);
-		// make close button functional
-		ImageView expiryWarningClose =
-				expiryWarning.findViewById(R.id.expiryWarningClose);
-
-		expiryWarningText.setText(getResources()
-				.getQuantityString(R.plurals.expiry_warning,
-						daysUntilExpiry, daysUntilExpiry));
-
-		expiryWarningClose.setOnClickListener(v -> {
-			controller.expiryWarningDismissed();
+		if (show) {
+			// show expiry warning text
+			TextView expiryWarningText =
+					expiryWarning.findViewById(R.id.expiryWarningText);
+			String text = getResources().getQuantityString(
+					R.plurals.expiry_warning, daysUntilExpiry, daysUntilExpiry);
+			expiryWarningText.setText(text);
+			// make close button functional
+			ImageView expiryWarningClose =
+					expiryWarning.findViewById(R.id.expiryWarningClose);
+			expiryWarningClose.setOnClickListener(v ->
+					viewModel.expiryWarningDismissed()
+			);
+			expiryWarning.setVisibility(VISIBLE);
+		} else {
 			expiryWarning.setVisibility(GONE);
-		});
-
-		expiryWarning.setVisibility(VISIBLE);
-	}
-
-	private void initializeTransports(LayoutInflater inflater) {
-		transports = new ArrayList<>(3);
-
-		Transport tor = new Transport();
-		tor.id = TorConstants.ID;
-		tor.enabled = controller.isTransportRunning(tor.id);
-		tor.iconId = R.drawable.transport_tor;
-		tor.textId = R.string.transport_tor;
-		transports.add(tor);
-
-		Transport bt = new Transport();
-		bt.id = BluetoothConstants.ID;
-		bt.enabled = controller.isTransportRunning(bt.id);
-		bt.iconId = R.drawable.transport_bt;
-		bt.textId = R.string.transport_bt;
-		transports.add(bt);
-
-		Transport lan = new Transport();
-		lan.id = LanTcpConstants.ID;
-		lan.enabled = controller.isTransportRunning(lan.id);
-		lan.iconId = R.drawable.transport_lan;
-		lan.textId = R.string.transport_lan;
-		transports.add(lan);
-
-		transportsAdapter = new BaseAdapter() {
-			@Override
-			public int getCount() {
-				return transports.size();
-			}
-
-			@Override
-			public Transport getItem(int position) {
-				return transports.get(position);
-			}
-
-			@Override
-			public long getItemId(int position) {
-				return 0;
-			}
-
-			@Override
-			public View getView(int position, View convertView,
-					ViewGroup parent) {
-				View view;
-				if (convertView != null) {
-					view = convertView;
-				} else {
-					view = inflater.inflate(R.layout.list_item_transport,
-							parent, false);
-				}
-
-				Transport t = getItem(position);
-				int c;
-				if (t.enabled) {
-					c = ContextCompat.getColor(NavDrawerActivity.this,
-							R.color.briar_green_light);
-				} else {
-					c = ContextCompat.getColor(NavDrawerActivity.this,
-							android.R.color.tertiary_text_light);
-				}
-
-				ImageView icon = view.findViewById(R.id.imageView);
-				icon.setImageDrawable(ContextCompat
-						.getDrawable(NavDrawerActivity.this, t.iconId));
-				icon.setColorFilter(c);
-
-				TextView text = view.findViewById(R.id.textView);
-				text.setText(getString(t.textId));
-
-				return view;
-			}
-		};
-	}
-
-	@UiThread
-	private void setTransport(TransportId id, boolean enabled) {
-		if (transports == null || transportsAdapter == null) return;
-		for (Transport t : transports) {
-			if (t.id.equals(id)) {
-				t.enabled = enabled;
-				transportsAdapter.notifyDataSetChanged();
-				break;
-			}
 		}
 	}
-
-	private void updateTransports() {
-		if (transports == null || transportsAdapter == null) return;
-		for (Transport t : transports) {
-			t.enabled = controller.isTransportRunning(t.id);
-		}
-		transportsAdapter.notifyDataSetChanged();
-	}
-
-	@Override
-	public void stateUpdate(TransportId id, boolean enabled) {
-		setTransport(id, enabled);
-	}
-
-	private static class Transport {
-
-		private TransportId id;
-		private boolean enabled;
-		private int iconId;
-		private int textId;
-	}
 }

briar-android/src/main/java/org/briarproject/briar/android/navdrawer/NavDrawerController.java

@@ -1,22 +0,0 @@
-package org.briarproject.briar.android.navdrawer;
-
-import android.content.Context;
-
-import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
-import org.briarproject.bramble.api.plugin.TransportId;
-import org.briarproject.briar.android.controller.ActivityLifecycleController;
-import org.briarproject.briar.android.controller.handler.ResultHandler;
-
-@NotNullByDefault
-public interface NavDrawerController extends ActivityLifecycleController {
-
-	boolean isTransportRunning(TransportId transportId);
-
-	void showExpiryWarning(ResultHandler<Boolean> handler);
-
-	void expiryWarningDismissed();
-
-	void shouldAskForDozeWhitelisting(Context ctx,
-			ResultHandler<Boolean> handler);
-
-}

briar-android/src/main/java/org/briarproject/briar/android/navdrawer/NavDrawerControllerImpl.java

@@ -1,182 +0,0 @@
-package org.briarproject.briar.android.navdrawer;
-
-import android.app.Activity;
-import android.content.Context;
-
-import org.briarproject.bramble.api.db.DatabaseExecutor;
-import org.briarproject.bramble.api.db.DbException;
-import org.briarproject.bramble.api.event.Event;
-import org.briarproject.bramble.api.event.EventBus;
-import org.briarproject.bramble.api.event.EventListener;
-import org.briarproject.bramble.api.lifecycle.LifecycleManager;
-import org.briarproject.bramble.api.nullsafety.MethodsNotNullByDefault;
-import org.briarproject.bramble.api.nullsafety.ParametersNotNullByDefault;
-import org.briarproject.bramble.api.plugin.Plugin;
-import org.briarproject.bramble.api.plugin.PluginManager;
-import org.briarproject.bramble.api.plugin.TransportId;
-import org.briarproject.bramble.api.plugin.event.TransportDisabledEvent;
-import org.briarproject.bramble.api.plugin.event.TransportEnabledEvent;
-import org.briarproject.bramble.api.settings.Settings;
-import org.briarproject.bramble.api.settings.SettingsManager;
-import org.briarproject.briar.android.controller.DbControllerImpl;
-import org.briarproject.briar.android.controller.handler.ResultHandler;
-
-import java.util.concurrent.Executor;
-import java.util.logging.Logger;
-
-import javax.inject.Inject;
-
-import static java.util.concurrent.TimeUnit.DAYS;
-import static java.util.logging.Level.INFO;
-import static java.util.logging.Level.WARNING;
-import static java.util.logging.Logger.getLogger;
-import static org.briarproject.bramble.util.LogUtils.logException;
-import static org.briarproject.briar.android.TestingConstants.EXPIRY_DATE;
-import static org.briarproject.briar.android.TestingConstants.IS_DEBUG_BUILD;
-import static org.briarproject.briar.android.controller.BriarControllerImpl.DOZE_ASK_AGAIN;
-import static org.briarproject.briar.android.settings.SettingsFragment.SETTINGS_NAMESPACE;
-import static org.briarproject.briar.android.util.UiUtils.needsDozeWhitelisting;
-
-@MethodsNotNullByDefault
-@ParametersNotNullByDefault
-public class NavDrawerControllerImpl extends DbControllerImpl
-		implements NavDrawerController, EventListener {
-
-	private static final Logger LOG =
-			getLogger(NavDrawerControllerImpl.class.getName());
-
-	private static final String EXPIRY_DATE_WARNING = "expiryDateWarning";
-
-	private final PluginManager pluginManager;
-	private final SettingsManager settingsManager;
-	private final EventBus eventBus;
-
-	// UI thread
-	private TransportStateListener listener;
-
-	@Inject
-	NavDrawerControllerImpl(@DatabaseExecutor Executor dbExecutor,
-			LifecycleManager lifecycleManager, PluginManager pluginManager,
-			SettingsManager settingsManager, EventBus eventBus) {
-		super(dbExecutor, lifecycleManager);
-		this.pluginManager = pluginManager;
-		this.settingsManager = settingsManager;
-		this.eventBus = eventBus;
-	}
-
-	@Override
-	public void onActivityCreate(Activity activity) {
-		listener = (TransportStateListener) activity;
-	}
-
-	@Override
-	public void onActivityStart() {
-		eventBus.addListener(this);
-	}
-
-	@Override
-	public void onActivityStop() {
-		eventBus.removeListener(this);
-	}
-
-	@Override
-	public void onActivityDestroy() {
-	}
-
-	@Override
-	public void eventOccurred(Event e) {
-		if (e instanceof TransportEnabledEvent) {
-			TransportId id = ((TransportEnabledEvent) e).getTransportId();
-			if (LOG.isLoggable(INFO)) {
-				LOG.info("TransportEnabledEvent: " + id.getString());
-			}
-			listener.stateUpdate(id, true);
-		} else if (e instanceof TransportDisabledEvent) {
-			TransportId id = ((TransportDisabledEvent) e).getTransportId();
-			if (LOG.isLoggable(INFO)) {
-				LOG.info("TransportDisabledEvent: " + id.getString());
-			}
-			listener.stateUpdate(id, false);
-		}
-	}
-
-	@Override
-	public void showExpiryWarning(ResultHandler<Boolean> handler) {
-		if (!IS_DEBUG_BUILD) {
-			handler.onResult(false);
-			return;
-		}
-		runOnDbThread(() -> {
-			try {
-				Settings settings =
-						settingsManager.getSettings(SETTINGS_NAMESPACE);
-				int warningInt = settings.getInt(EXPIRY_DATE_WARNING, 0);
-
-				if (warningInt == 0) {
-					// we have not warned before
-					handler.onResult(true);
-				} else {
-					long warningLong = warningInt * 1000L;
-					long now = System.currentTimeMillis();
-					long daysSinceLastWarning =
-							(now - warningLong) / DAYS.toMillis(1);
-					long daysBeforeExpiry =
-							(EXPIRY_DATE - now) / DAYS.toMillis(1);
-
-					if (daysSinceLastWarning >= 30) {
-						handler.onResult(true);
-					} else if (daysBeforeExpiry <= 3 &&
-							daysSinceLastWarning > 0) {
-						handler.onResult(true);
-					} else {
-						handler.onResult(false);
-					}
-				}
-			} catch (DbException e) {
-				logException(LOG, WARNING, e);
-			}
-		});
-	}
-
-	@Override
-	public void expiryWarningDismissed() {
-		runOnDbThread(() -> {
-			try {
-				Settings settings = new Settings();
-				int date = (int) (System.currentTimeMillis() / 1000L);
-				settings.putInt(EXPIRY_DATE_WARNING, date);
-				settingsManager.mergeSettings(settings, SETTINGS_NAMESPACE);
-			} catch (DbException e) {
-				logException(LOG, WARNING, e);
-			}
-		});
-	}
-
-	@Override
-	public void shouldAskForDozeWhitelisting(Context ctx,
-			ResultHandler<Boolean> handler) {
-		// check this first, to hit the DbThread only when really necessary
-		if (!needsDozeWhitelisting(ctx)) {
-			handler.onResult(false);
-			return;
-		}
-		runOnDbThread(() -> {
-			try {
-				Settings settings =
-						settingsManager.getSettings(SETTINGS_NAMESPACE);
-				boolean ask = settings.getBoolean(DOZE_ASK_AGAIN, true);
-				handler.onResult(ask);
-			} catch (DbException e) {
-				logException(LOG, WARNING, e);
-				handler.onResult(true);
-			}
-		});
-	}
-
-	@Override
-	public boolean isTransportRunning(TransportId transportId) {
-		Plugin plugin = pluginManager.getPlugin(transportId);
-		return plugin != null && plugin.isRunning();
-	}
-
-}

briar-android/src/main/java/org/briarproject/briar/android/navdrawer/NavDrawerModule.java

@@ -0,0 +1,19 @@
+package org.briarproject.briar.android.navdrawer;
+
+import org.briarproject.briar.android.viewmodel.ViewModelKey;
+
+import androidx.lifecycle.ViewModel;
+import dagger.Binds;
+import dagger.Module;
+import dagger.multibindings.IntoMap;
+
+@Module
+public abstract class NavDrawerModule {
+
+	@Binds
+	@IntoMap
+	@ViewModelKey(NavDrawerViewModel.class)
+	abstract ViewModel bindNavDrawerViewModel(
+			NavDrawerViewModel navDrawerViewModel);
+
+}

briar-android/src/main/java/org/briarproject/briar/android/navdrawer/NavDrawerViewModel.java

@@ -0,0 +1,255 @@
+package org.briarproject.briar.android.navdrawer;
+
+import android.app.Application;
+
+import org.briarproject.bramble.api.db.DatabaseExecutor;
+import org.briarproject.bramble.api.db.DbException;
+import org.briarproject.bramble.api.event.Event;
+import org.briarproject.bramble.api.event.EventBus;
+import org.briarproject.bramble.api.event.EventListener;
+import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
+import org.briarproject.bramble.api.plugin.BluetoothConstants;
+import org.briarproject.bramble.api.plugin.LanTcpConstants;
+import org.briarproject.bramble.api.plugin.Plugin;
+import org.briarproject.bramble.api.plugin.Plugin.State;
+import org.briarproject.bramble.api.plugin.PluginManager;
+import org.briarproject.bramble.api.plugin.TorConstants;
+import org.briarproject.bramble.api.plugin.TransportId;
+import org.briarproject.bramble.api.plugin.event.TransportStateEvent;
+import org.briarproject.bramble.api.settings.Settings;
+import org.briarproject.bramble.api.settings.SettingsManager;
+import org.briarproject.bramble.api.system.LocationUtils;
+
+import java.util.concurrent.Executor;
+import java.util.logging.Logger;
+
+import javax.inject.Inject;
+
+import androidx.annotation.Nullable;
+import androidx.annotation.UiThread;
+import androidx.lifecycle.AndroidViewModel;
+import androidx.lifecycle.LiveData;
+import androidx.lifecycle.MutableLiveData;
+
+import static java.util.concurrent.TimeUnit.DAYS;
+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.STARTING_STOPPING;
+import static org.briarproject.bramble.api.plugin.TorConstants.PREF_TOR_MOBILE;
+import static org.briarproject.bramble.api.plugin.TorConstants.PREF_TOR_NETWORK;
+import static org.briarproject.bramble.api.plugin.TorConstants.PREF_TOR_NETWORK_WITH_BRIDGES;
+import static org.briarproject.bramble.api.plugin.TorConstants.PREF_TOR_ONLY_WHEN_CHARGING;
+import static org.briarproject.bramble.util.LogUtils.logException;
+import static org.briarproject.briar.android.TestingConstants.EXPIRY_DATE;
+import static org.briarproject.briar.android.TestingConstants.IS_DEBUG_BUILD;
+import static org.briarproject.briar.android.controller.BriarControllerImpl.DOZE_ASK_AGAIN;
+import static org.briarproject.briar.android.settings.SettingsFragment.SETTINGS_NAMESPACE;
+import static org.briarproject.briar.android.util.UiUtils.getCountryDisplayName;
+import static org.briarproject.briar.android.util.UiUtils.needsDozeWhitelisting;
+
+@NotNullByDefault
+public class NavDrawerViewModel extends AndroidViewModel
+		implements EventListener {
+
+	private static final Logger LOG =
+			getLogger(NavDrawerViewModel.class.getName());
+
+	private static final String EXPIRY_DATE_WARNING = "expiryDateWarning";
+	static final TransportId[] TRANSPORT_IDS =
+			{TorConstants.ID, LanTcpConstants.ID, BluetoothConstants.ID};
+
+	@DatabaseExecutor
+	private final Executor dbExecutor;
+	private final SettingsManager settingsManager;
+	private final PluginManager pluginManager;
+	private final LocationUtils locationUtils;
+	private final EventBus eventBus;
+
+	private final MutableLiveData<Boolean> showExpiryWarning =
+			new MutableLiveData<>();
+	private final MutableLiveData<Boolean> shouldAskForDozeWhitelisting =
+			new MutableLiveData<>();
+
+	private final MutableLiveData<Plugin.State> torPluginState =
+			new MutableLiveData<>();
+	private final MutableLiveData<Plugin.State> wifiPluginState =
+			new MutableLiveData<>();
+	private final MutableLiveData<Plugin.State> btPluginState =
+			new MutableLiveData<>();
+
+	@Inject
+	NavDrawerViewModel(Application app, @DatabaseExecutor Executor dbExecutor,
+			SettingsManager settingsManager, PluginManager pluginManager,
+			LocationUtils locationUtils, EventBus eventBus) {
+		super(app);
+		this.dbExecutor = dbExecutor;
+		this.settingsManager = settingsManager;
+		this.pluginManager = pluginManager;
+		this.locationUtils = locationUtils;
+		this.eventBus = eventBus;
+		eventBus.addListener(this);
+		updatePluginStates();
+	}
+
+	@Override
+	protected void onCleared() {
+		eventBus.removeListener(this);
+	}
+
+	@Override
+	public void eventOccurred(Event e) {
+		if (e instanceof TransportStateEvent) {
+			TransportStateEvent t = (TransportStateEvent) e;
+			TransportId id = t.getTransportId();
+			State state = t.getState();
+			if (LOG.isLoggable(INFO)) {
+				LOG.info("TransportStateEvent: " + id + " is " + state);
+			}
+			MutableLiveData<Plugin.State> liveData = getPluginLiveData(id);
+			if (liveData != null) liveData.postValue(state);
+		}
+	}
+
+	LiveData<Boolean> showExpiryWarning() {
+		return showExpiryWarning;
+	}
+
+	@UiThread
+	void checkExpiryWarning() {
+		if (!IS_DEBUG_BUILD) {
+			showExpiryWarning.setValue(false);
+			return;
+		}
+		dbExecutor.execute(() -> {
+			try {
+				Settings settings =
+						settingsManager.getSettings(SETTINGS_NAMESPACE);
+				int warningInt = settings.getInt(EXPIRY_DATE_WARNING, 0);
+
+				if (warningInt == 0) {
+					// we have not warned before
+					showExpiryWarning.postValue(true);
+				} else {
+					long warningLong = warningInt * 1000L;
+					long now = System.currentTimeMillis();
+					long daysSinceLastWarning =
+							(now - warningLong) / DAYS.toMillis(1);
+					long daysBeforeExpiry =
+							(EXPIRY_DATE - now) / DAYS.toMillis(1);
+
+					if (daysSinceLastWarning >= 30) {
+						showExpiryWarning.postValue(true);
+					} else if (daysBeforeExpiry <= 3 &&
+							daysSinceLastWarning > 0) {
+						showExpiryWarning.postValue(true);
+					} else {
+						showExpiryWarning.postValue(false);
+					}
+				}
+			} catch (DbException e) {
+				logException(LOG, WARNING, e);
+			}
+		});
+	}
+
+	@UiThread
+	void expiryWarningDismissed() {
+		showExpiryWarning.setValue(false);
+		dbExecutor.execute(() -> {
+			try {
+				Settings settings = new Settings();
+				int date = (int) (System.currentTimeMillis() / 1000L);
+				settings.putInt(EXPIRY_DATE_WARNING, date);
+				settingsManager.mergeSettings(settings, SETTINGS_NAMESPACE);
+			} catch (DbException e) {
+				logException(LOG, WARNING, e);
+			}
+		});
+	}
+
+	LiveData<Boolean> shouldAskForDozeWhitelisting() {
+		return shouldAskForDozeWhitelisting;
+	}
+
+	@UiThread
+	void checkDozeWhitelisting() {
+		// check this first, to hit the DbThread only when really necessary
+		if (!needsDozeWhitelisting(getApplication())) {
+			shouldAskForDozeWhitelisting.setValue(false);
+			return;
+		}
+		dbExecutor.execute(() -> {
+			try {
+				Settings settings =
+						settingsManager.getSettings(SETTINGS_NAMESPACE);
+				boolean ask = settings.getBoolean(DOZE_ASK_AGAIN, true);
+				shouldAskForDozeWhitelisting.postValue(ask);
+			} catch (DbException e) {
+				logException(LOG, WARNING, e);
+				shouldAskForDozeWhitelisting.postValue(true);
+			}
+		});
+	}
+
+	private void updatePluginStates() {
+		for (TransportId t : TRANSPORT_IDS) {
+			MutableLiveData<Plugin.State> liveData = getPluginLiveData(t);
+			if (liveData == null) throw new AssertionError();
+			liveData.setValue(getTransportState(t));
+		}
+	}
+
+	private State getTransportState(TransportId id) {
+		Plugin plugin = pluginManager.getPlugin(id);
+		return plugin == null ? STARTING_STOPPING : plugin.getState();
+	}
+
+	@Nullable
+	private MutableLiveData<State> getPluginLiveData(TransportId t) {
+		if (t.equals(TorConstants.ID)) {
+			return torPluginState;
+		} else if (t.equals(LanTcpConstants.ID)) {
+			return wifiPluginState;
+		} else if (t.equals(BluetoothConstants.ID)) {
+			return btPluginState;
+		} else {
+			return null;
+		}
+	}
+
+	LiveData<State> getPluginState(TransportId t) {
+		LiveData<Plugin.State> liveData = getPluginLiveData(t);
+		if (liveData == null) throw new AssertionError();
+		return liveData;
+	}
+
+	int getReasonsDisabled(TransportId id) {
+		Plugin plugin = pluginManager.getPlugin(id);
+		return plugin == null ? 0 : plugin.getReasonsDisabled();
+	}
+
+	void setPluginEnabled(TransportId t, boolean enabled) {
+		pluginManager.setPluginEnabled(t, enabled);
+	}
+
+	void setTorEnabled(boolean battery, boolean mobileData, boolean location) {
+		Settings s = new Settings();
+		s.putBoolean(PREF_PLUGIN_ENABLE, true);
+		if (battery) s.putBoolean(PREF_TOR_ONLY_WHEN_CHARGING, false);
+		if (mobileData) s.putBoolean(PREF_TOR_MOBILE, true);
+		if (location) s.putInt(PREF_TOR_NETWORK, PREF_TOR_NETWORK_WITH_BRIDGES);
+		dbExecutor.execute(() -> {
+			try {
+				settingsManager.mergeSettings(s, TorConstants.ID.getString());
+			} catch (DbException e) {
+				logException(LOG, WARNING, e);
+			}
+		});
+	}
+
+	String getCurrentCountryName() {
+		return getCountryDisplayName(locationUtils.getCurrentCountry());
+	}
+}

briar-android/src/main/java/org/briarproject/briar/android/navdrawer/PluginViewController.java

@@ -0,0 +1,213 @@
+package org.briarproject.briar.android.navdrawer;
+
+import android.content.Intent;
+import android.content.pm.PackageManager;
+import android.view.View;
+import android.widget.ImageView;
+import android.widget.ScrollView;
+
+import org.briarproject.bramble.api.plugin.BluetoothConstants;
+import org.briarproject.bramble.api.plugin.LanTcpConstants;
+import org.briarproject.bramble.api.plugin.Plugin.State;
+import org.briarproject.bramble.api.plugin.TorConstants;
+import org.briarproject.bramble.api.plugin.TransportId;
+import org.briarproject.briar.R;
+
+import androidx.appcompat.app.AlertDialog;
+import androidx.appcompat.app.AppCompatActivity;
+import androidx.appcompat.widget.AppCompatImageButton;
+import androidx.appcompat.widget.SwitchCompat;
+import androidx.constraintlayout.widget.ConstraintLayout;
+import androidx.constraintlayout.widget.ConstraintSet;
+import androidx.core.app.ActivityCompat;
+
+import static android.bluetooth.BluetoothAdapter.ACTION_REQUEST_DISCOVERABLE;
+import static android.bluetooth.BluetoothAdapter.EXTRA_DISCOVERABLE_DURATION;
+import static android.os.Build.VERSION.SDK_INT;
+import static android.transition.TransitionManager.beginDelayedTransition;
+import static android.view.View.FOCUS_DOWN;
+import static androidx.core.content.ContextCompat.getColor;
+import static org.briarproject.bramble.api.plugin.Plugin.REASON_USER;
+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.STARTING_STOPPING;
+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.briar.android.navdrawer.NavDrawerViewModel.TRANSPORT_IDS;
+import static org.briarproject.briar.android.util.UiUtils.getDialogIcon;
+
+class PluginViewController {
+
+	private final AppCompatActivity activity;
+	private final NavDrawerViewModel viewModel;
+	private final ConstraintLayout drawerContent;
+	private final ConstraintSet collapsedConstraints, expandedConstraints;
+	private final AppCompatImageButton chevronView;
+	private final ImageView torIcon, wifiIcon, btIcon;
+	private final SwitchCompat torSwitch, wifiSwitch, btSwitch;
+
+	private boolean expanded = false;
+
+	PluginViewController(View v, AppCompatActivity activity,
+			NavDrawerViewModel viewModel) {
+		this.activity = activity;
+		this.viewModel = viewModel;
+		drawerContent = v.findViewById(R.id.drawerContent);
+
+		collapsedConstraints = new ConstraintSet();
+		collapsedConstraints.clone(v.getContext(),
+				R.layout.navigation_menu_collapsed);
+
+		expandedConstraints = new ConstraintSet();
+		expandedConstraints.clone(v.getContext(),
+				R.layout.navigation_menu_expanded);
+
+		// Scroll the drawer to the bottom when the view is expanded/collapsed
+		ScrollView scrollView = v.findViewById(R.id.drawerScrollView);
+		drawerContent.addOnLayoutChangeListener((view, left, top, right,
+				bottom, oldLeft, oldTop, oldRight, oldBottom) ->
+				scrollView.fullScroll(FOCUS_DOWN));
+
+		// Clicking the chevron expands or collapses the view
+		chevronView = v.findViewById(R.id.chevronView);
+		chevronView.setOnClickListener(view -> expandOrCollapseView());
+
+		// The whole view is clickable when collapsed
+		v.findViewById(R.id.connectionsBackground).setOnClickListener(view ->
+				expandOrCollapseView());
+
+		torIcon = v.findViewById(R.id.torIcon);
+		wifiIcon = v.findViewById(R.id.wifiIcon);
+		btIcon = v.findViewById(R.id.btIcon);
+
+		torSwitch = v.findViewById(R.id.torSwitch);
+		wifiSwitch = v.findViewById(R.id.wifiSwitch);
+		btSwitch = v.findViewById(R.id.btSwitch);
+
+		for (TransportId t : TRANSPORT_IDS) {
+			// a OnCheckedChangeListener would get triggered on programmatic updates
+			SwitchCompat switchCompat = getSwitch(t);
+			switchCompat.setOnClickListener(buttonView -> {
+				if (switchCompat.isChecked()) tryToEnablePlugin(t);
+				else viewModel.setPluginEnabled(t, false);
+				// Revert the switch to its previous state until the plugin
+				// changes its state
+				switchCompat.toggle();
+			});
+			viewModel.getPluginState(t).observe(activity, state ->
+					stateUpdate(t, state));
+		}
+	}
+
+	private void expandOrCollapseView() {
+		if (SDK_INT >= 19) beginDelayedTransition(drawerContent);
+		if (expanded) {
+			collapsedConstraints.applyTo(drawerContent);
+			chevronView.setImageResource(R.drawable.chevron_up_white);
+		} else {
+			expandedConstraints.applyTo(drawerContent);
+			chevronView.setImageResource(R.drawable.chevron_down_white);
+		}
+		expanded = !expanded;
+	}
+
+	private void tryToEnablePlugin(TransportId id) {
+		if (id.equals(TorConstants.ID)) {
+			int reasons = viewModel.getReasonsDisabled(id);
+			if (reasons == 0 || reasons == REASON_USER) {
+				viewModel.setPluginEnabled(id, true);
+			} else {
+				showTorSettingsDialog(reasons);
+			}
+		} else if (id.equals(BluetoothConstants.ID)) {
+			Intent i = new Intent(ACTION_REQUEST_DISCOVERABLE);
+			i.putExtra(EXTRA_DISCOVERABLE_DURATION, 0);
+			PackageManager pm = activity.getPackageManager();
+			if (i.resolveActivity(pm) != null) {
+				ActivityCompat.startActivity(activity, i, null);
+			}
+			viewModel.setPluginEnabled(id, true);
+		} else {
+			viewModel.setPluginEnabled(id, true);
+		}
+	}
+
+	private void stateUpdate(TransportId id, State state) {
+		updateIcon(getIcon(id), state);
+		updateSwitch(getSwitch(id), state);
+	}
+
+	private SwitchCompat getSwitch(TransportId id) {
+		if (id == TorConstants.ID) return torSwitch;
+		if (id == BluetoothConstants.ID) return btSwitch;
+		if (id == LanTcpConstants.ID) return wifiSwitch;
+		throw new AssertionError();
+	}
+
+	private void updateSwitch(SwitchCompat switchCompat, State state) {
+		boolean checked = state != STARTING_STOPPING && state != DISABLED;
+		switchCompat.setChecked(checked);
+		switchCompat.setEnabled(state != STARTING_STOPPING);
+	}
+
+	private ImageView getIcon(TransportId id) {
+		if (id == TorConstants.ID) return torIcon;
+		if (id == BluetoothConstants.ID) return btIcon;
+		if (id == LanTcpConstants.ID) return wifiIcon;
+		throw new AssertionError();
+	}
+
+	private void updateIcon(ImageView icon, State state) {
+		int colorRes;
+		if (state == ACTIVE) {
+			colorRes = R.color.briar_green_light;
+		} else if (state == ENABLING) {
+			colorRes = R.color.briar_yellow;
+		} else {
+			colorRes = android.R.color.tertiary_text_light;
+		}
+		int color = getColor(icon.getContext(), colorRes);
+		icon.setColorFilter(color);
+	}
+
+	private void showTorSettingsDialog(int reasonsDisabled) {
+		boolean battery = (reasonsDisabled & REASON_BATTERY) != 0;
+		boolean mobileData = (reasonsDisabled & REASON_MOBILE_DATA) != 0;
+		boolean location = (reasonsDisabled & REASON_COUNTRY_BLOCKED) != 0;
+
+		StringBuilder s = new StringBuilder();
+		if (location) {
+			s.append("\t\u2022 ");
+			s.append(activity.getString(R.string.tor_override_network_setting,
+					viewModel.getCurrentCountryName()));
+			s.append('\n');
+		}
+		if (mobileData) {
+			s.append("\t\u2022 ");
+			s.append(activity.getString(
+					R.string.tor_override_mobile_data_setting));
+			s.append('\n');
+		}
+		if (battery) {
+			s.append("\t\u2022 ");
+			s.append(activity.getString(R.string.tor_only_when_charging_title));
+			s.append('\n');
+		}
+		String message = activity.getString(
+				R.string.tor_override_settings_body, s.toString());
+
+		AlertDialog.Builder b =
+				new AlertDialog.Builder(activity, R.style.BriarDialogTheme);
+		b.setTitle(R.string.tor_override_settings_title);
+		b.setIcon(getDialogIcon(activity, R.drawable.ic_settings_black_24dp));
+		b.setMessage(message);
+		b.setPositiveButton(R.string.tor_override_settings_confirm,
+				(dialog, which) ->
+						viewModel.setTorEnabled(battery, mobileData, location));
+		b.setNegativeButton(R.string.cancel, (dialog, which) ->
+				dialog.dismiss());
+		b.show();
+	}
+}

briar-android/src/main/java/org/briarproject/briar/android/navdrawer/TransportStateListener.java

@@ -1,11 +0,0 @@
-package org.briarproject.briar.android.navdrawer;
-
-import org.briarproject.bramble.api.plugin.TransportId;
-
-import androidx.annotation.UiThread;
-
-interface TransportStateListener {
-
-	@UiThread
-	void stateUpdate(TransportId id, boolean enabled);
-}