Merge branch 'plugin-toggle-settings' into 'plugin-toggles'

Add toggle settings for transport plugins

See merge request briar/briar!1211

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;
@@ -36,10 +36,11 @@ 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.api.plugin.TcpConstants.PREF_TCP_ENABLE;
 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());
@@ -83,7 +84,8 @@ class AndroidLanTcpPlugin extends LanTcpPlugin implements EventListener {
 	@Override
 	public void start() {
 		if (used.getAndSet(true)) throw new IllegalStateException();
-		state.setStarted();
+		Settings settings = callback.getSettings();
+		state.setStarted(settings.getBoolean(PREF_TCP_ENABLE, false));
 		updateConnectionStatus();
 	}
 
@@ -136,6 +138,7 @@ class AndroidLanTcpPlugin extends LanTcpPlugin implements EventListener {
 
 	@Override
 	public void eventOccurred(Event e) {
+		super.eventOccurred(e);
 		if (e instanceof NetworkStatusEvent) updateConnectionStatus();
 	}
 

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

@@ -10,4 +10,7 @@ public interface BluetoothConstants {
 	String PROP_UUID = "uuid";
 
 	String PREF_BT_ENABLE = "enable";
+
+	// Reason code returned by Plugin#getReasonDisabled()
+	int REASON_NO_BT_ADAPTER = 2;
 }

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

@@ -35,12 +35,18 @@ public interface Plugin {
 	}
 
 	/**
-	 * Reason code returned by {@link #getReasonDisabled()} ()} to indicate
-	 * that the plugin is disabled because it has not been started or has been
+	 * Reason code returned by {@link #getReasonDisabled()} to indicate that
+	 * the plugin is disabled because it has not been started or has been
 	 * stopped.
 	 */
 	int REASON_STARTING_STOPPING = 0;
 
+	/**
+	 * Reason code returned by {@link #getReasonDisabled()} to indicate that
+	 * the plugin has been disabled by the user.
+	 */
+	int REASON_USER = 1;
+
 	/**
 	 * Returns the plugin's transport identifier.
 	 */
@@ -75,9 +81,9 @@ public interface Plugin {
 	 * Returns an integer code indicating why the plugin is
 	 * {@link State#DISABLED disabled}, or -1 if the plugin is not disabled.
 	 * <p>
-	 * The codes used are plugin-specific, except the generic code
-	 * {@link #REASON_STARTING_STOPPING}, which may be used by
-	 * any plugin.
+	 * The codes used are plugin-specific, except the generic codes
+	 * {@link #REASON_STARTING_STOPPING} and {@link #REASON_USER}, which may
+	 * be used by any plugin.
 	 */
 	int getReasonDisabled();
 

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

@@ -0,0 +1,6 @@
+package org.briarproject.bramble.api.plugin;
+
+public interface TcpConstants {
+
+	String PREF_TCP_ENABLE = "enable";
+}

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

@@ -13,6 +13,7 @@ public interface TorConstants {
 	int CONNECT_TO_PROXY_TIMEOUT = 5000; // Milliseconds
 	int EXTRA_SOCKET_TIMEOUT = 30000; // Milliseconds
 
+	String PREF_TOR_ENABLE = "enable";
 	String PREF_TOR_NETWORK = "network2";
 	String PREF_TOR_PORT = "port";
 	String PREF_TOR_MOBILE = "useMobileData";
@@ -23,7 +24,7 @@ public interface TorConstants {
 	int PREF_TOR_NETWORK_WITH_BRIDGES = 2;
 	int PREF_TOR_NETWORK_NEVER = 3;
 
-	int REASON_USER = 1;
+	// Reason codes returned by Plugin#getReasonDisabled()
 	int REASON_BATTERY = 2;
 	int REASON_MOBILE_DATA = 3;
 	int REASON_COUNTRY_BLOCKED = 4;

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

@@ -9,6 +9,7 @@ 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;
@@ -48,6 +49,7 @@ import static org.briarproject.bramble.api.plugin.BluetoothConstants.ID;
 import static org.briarproject.bramble.api.plugin.BluetoothConstants.PREF_BT_ENABLE;
 import static org.briarproject.bramble.api.plugin.BluetoothConstants.PROP_ADDRESS;
 import static org.briarproject.bramble.api.plugin.BluetoothConstants.PROP_UUID;
+import static org.briarproject.bramble.api.plugin.BluetoothConstants.REASON_NO_BT_ADAPTER;
 import static org.briarproject.bramble.api.plugin.BluetoothConstants.UUID_BYTES;
 import static org.briarproject.bramble.api.plugin.Plugin.State.ACTIVE;
 import static org.briarproject.bramble.api.plugin.Plugin.State.DISABLED;
@@ -76,7 +78,6 @@ abstract class BluetoothPlugin<SS> implements DuplexPlugin, EventListener {
 
 	protected final PluginState state = new PluginState();
 
-	private volatile boolean contactConnections = false;
 	private volatile String contactConnectionsUuid = null;
 
 	abstract void initialiseAdapter() throws IOException;
@@ -126,16 +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();
-		callback.pluginStateChanged(getState());
+		if (getState() == INACTIVE) bind();
 	}
 
 	void onAdapterDisabled() {
 		LOG.info("Bluetooth disabled");
 		connectionLimiter.allConnectionsClosed();
 		// The server socket may not have been closed automatically
-		tryToClose(state.clearServerSocket());
-		callback.pluginStateChanged(getState());
+		SS ss = state.clearServerSocket();
+		if (ss != null) {
+			LOG.info("Closing server socket");
+			tryToClose(ss);
+		}
 	}
 
 	@Override
@@ -160,29 +163,22 @@ abstract class BluetoothPlugin<SS> implements DuplexPlugin, EventListener {
 		try {
 			initialiseAdapter();
 		} catch (IOException e) {
+			state.setNoAdapter();
 			throw new PluginException(e);
 		}
 		updateProperties();
-		state.setStarted();
-		loadSettings(callback.getSettings());
-		if (shouldAllowContactConnections()) {
+		Settings settings = callback.getSettings();
+		boolean enabledByUser = settings.getBoolean(PREF_BT_ENABLE, false);
+		state.setStarted(enabledByUser);
+		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 (!shouldAllowContactConnections() || getState() != ACTIVE)
-				return;
+			if (getState() != INACTIVE) return;
 			// Bind a server socket to accept connections from contacts
 			SS ss;
 			try {
@@ -191,8 +187,7 @@ abstract class BluetoothPlugin<SS> implements DuplexPlugin, EventListener {
 				logException(LOG, WARNING, e);
 				return;
 			}
-			if (!shouldAllowContactConnections() ||
-					!state.setServerSocket(ss)) {
+			if (!state.setServerSocket(ss)) {
 				LOG.info("Closing redundant server socket");
 				tryToClose(ss);
 				return;
@@ -259,7 +254,7 @@ abstract class BluetoothPlugin<SS> implements DuplexPlugin, EventListener {
 
 	@Override
 	public int getReasonDisabled() {
-		return getState() == DISABLED ? REASON_STARTING_STOPPING : -1;
+		return state.getReasonDisabled();
 	}
 
 	@Override
@@ -275,7 +270,7 @@ abstract class BluetoothPlugin<SS> implements DuplexPlugin, EventListener {
 	@Override
 	public void poll(Collection<Pair<TransportProperties, ConnectionHandler>>
 			properties) {
-		if (!shouldAllowContactConnections() || getState() != ACTIVE) return;
+		if (getState() != ACTIVE) return;
 		backoff.increment();
 		for (Pair<TransportProperties, ConnectionHandler> p : properties) {
 			connect(p.getFirst(), p.getSecond());
@@ -288,8 +283,7 @@ abstract class BluetoothPlugin<SS> implements DuplexPlugin, EventListener {
 		String uuid = p.get(PROP_UUID);
 		if (isNullOrEmpty(uuid)) return;
 		ioExecutor.execute(() -> {
-			if (!shouldAllowContactConnections() || getState() != ACTIVE)
-				return;
+			if (getState() != ACTIVE) return;
 			if (!connectionLimiter.canOpenContactConnection()) return;
 			DuplexTransportConnection d = createConnection(p);
 			if (d != null) {
@@ -333,8 +327,7 @@ abstract class BluetoothPlugin<SS> implements DuplexPlugin, EventListener {
 
 	@Override
 	public DuplexTransportConnection createConnection(TransportProperties p) {
-		if (!shouldAllowContactConnections() || getState() != ACTIVE)
-			return null;
+		if (getState() != ACTIVE) return null;
 		if (!connectionLimiter.canOpenContactConnection()) return null;
 		String address = p.get(PROP_ADDRESS);
 		if (isNullOrEmpty(address)) return null;
@@ -439,16 +432,17 @@ 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(state.clearServerSocket());
+		boolean enabledByUser = settings.getBoolean(PREF_BT_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();
 		}
@@ -482,13 +476,18 @@ abstract class BluetoothPlugin<SS> implements DuplexPlugin, EventListener {
 	protected class PluginState {
 
 		@GuardedBy("this")
-		private boolean started = false, stopped = false;
+		private boolean started = false,
+				stopped = false,
+				noAdapter = false,
+				enabledByUser = false;
+
 		@GuardedBy("this")
 		@Nullable
 		private SS serverSocket = null;
 
-		synchronized void setStarted() {
+		synchronized void setStarted(boolean enabledByUser) {
 			started = true;
+			this.enabledByUser = enabledByUser;
 			callback.pluginStateChanged(getState());
 		}
 
@@ -501,6 +500,23 @@ abstract class BluetoothPlugin<SS> implements DuplexPlugin, EventListener {
 			return ss;
 		}
 
+		synchronized void setNoAdapter() {
+			noAdapter = true;
+			callback.pluginStateChanged(getState());
+		}
+
+		@Nullable
+		synchronized SS setEnabledByUser(boolean enabledByUser) {
+			this.enabledByUser = enabledByUser;
+			SS ss = null;
+			if (!enabledByUser) {
+				ss = serverSocket;
+				serverSocket = null;
+			}
+			callback.pluginStateChanged(getState());
+			return ss;
+		}
+
 		synchronized boolean setServerSocket(SS ss) {
 			if (stopped || serverSocket != null) return false;
 			serverSocket = ss;
@@ -512,12 +528,19 @@ abstract class BluetoothPlugin<SS> implements DuplexPlugin, EventListener {
 		synchronized SS clearServerSocket() {
 			SS ss = serverSocket;
 			serverSocket = null;
+			callback.pluginStateChanged(getState());
 			return ss;
 		}
 
 		synchronized State getState() {
-			if (!started || stopped) return DISABLED;
-			return isAdapterEnabled() ? ACTIVE : INACTIVE;
+			if (!started || stopped || !enabledByUser) return DISABLED;
+			return serverSocket == null ? INACTIVE : ACTIVE;
+		}
+
+		synchronized int getReasonDisabled() {
+			if (noAdapter && !stopped) return REASON_NO_BT_ADAPTER;
+			if (!started || stopped) return REASON_STARTING_STOPPING;
+			return enabledByUser ? -1 : REASON_USER;
 		}
 	}
 }

bramble-core/src/main/java/org/briarproject/bramble/plugin/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;
@@ -25,11 +26,13 @@ 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;
 	}
 
@@ -47,7 +50,9 @@ 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,
-				MAX_IDLE_TIME);
+		LanTcpPlugin plugin = new LanTcpPlugin(ioExecutor, backoff, callback,
+				MAX_LATENCY, MAX_IDLE_TIME);
+		eventBus.addListener(plugin);
+		return plugin;
 	}
 }

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

@@ -3,7 +3,10 @@ package org.briarproject.bramble.plugin.tcp;
 import org.briarproject.bramble.PoliteExecutor;
 import org.briarproject.bramble.api.Pair;
 import org.briarproject.bramble.api.data.BdfList;
+import org.briarproject.bramble.api.event.Event;
+import org.briarproject.bramble.api.event.EventListener;
 import org.briarproject.bramble.api.keyagreement.KeyAgreementListener;
+import org.briarproject.bramble.api.lifecycle.IoExecutor;
 import org.briarproject.bramble.api.nullsafety.MethodsNotNullByDefault;
 import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
 import org.briarproject.bramble.api.nullsafety.ParametersNotNullByDefault;
@@ -15,6 +18,8 @@ import org.briarproject.bramble.api.plugin.duplex.DuplexTransportConnection;
 import org.briarproject.bramble.api.properties.TransportProperties;
 import org.briarproject.bramble.api.rendezvous.KeyMaterialSource;
 import org.briarproject.bramble.api.rendezvous.RendezvousEndpoint;
+import org.briarproject.bramble.api.settings.Settings;
+import org.briarproject.bramble.api.settings.event.SettingsUpdatedEvent;
 
 import java.io.IOException;
 import java.net.InetAddress;
@@ -46,6 +51,7 @@ 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.TcpConstants.PREF_TCP_ENABLE;
 import static org.briarproject.bramble.util.IoUtils.tryToClose;
 import static org.briarproject.bramble.util.LogUtils.logException;
 import static org.briarproject.bramble.util.PrivacyUtils.scrubSocketAddress;
@@ -53,7 +59,7 @@ 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());
 
@@ -119,7 +125,8 @@ abstract class TcpPlugin implements DuplexPlugin {
 	@Override
 	public void start() {
 		if (used.getAndSet(true)) throw new IllegalStateException();
-		state.setStarted();
+		Settings settings = callback.getSettings();
+		state.setStarted(settings.getBoolean(PREF_TCP_ENABLE, false));
 		bind();
 	}
 
@@ -197,7 +204,7 @@ abstract class TcpPlugin implements DuplexPlugin {
 
 	@Override
 	public int getReasonDisabled() {
-		return getState() == DISABLED ? REASON_STARTING_STOPPING : -1;
+		return state.getReasonDisabled();
 	}
 
 	@Override
@@ -331,18 +338,43 @@ abstract class TcpPlugin implements DuplexPlugin {
 		}
 	}
 
+	@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_TCP_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;
+		private boolean started = false, stopped = false, enabledByUser = false;
+
 		@GuardedBy("this")
 		@Nullable
 		private ServerSocket serverSocket = null;
 
-		synchronized void setStarted() {
+		synchronized void setStarted(boolean enabledByUser) {
 			started = true;
+			this.enabledByUser = enabledByUser;
 			callback.pluginStateChanged(getState());
 		}
 
@@ -355,6 +387,18 @@ abstract class TcpPlugin implements DuplexPlugin {
 			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;
@@ -373,8 +417,13 @@ abstract class TcpPlugin implements DuplexPlugin {
 		}
 
 		synchronized State getState() {
-			if (!started || stopped) return DISABLED;
+			if (!started || stopped || !enabledByUser) return DISABLED;
 			return serverSocket == null ? INACTIVE : ACTIVE;
 		}
+
+		synchronized int getReasonDisabled() {
+			if (!started || stopped) return REASON_STARTING_STOPPING;
+			return enabledByUser ? -1 : REASON_USER;
+		}
 	}
 }

bramble-core/src/main/java/org/briarproject/bramble/plugin/tcp/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;
@@ -26,12 +27,14 @@ 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;
 	}
@@ -50,8 +53,10 @@ 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);
+		eventBus.addListener(plugin);
+		return plugin;
 	}
 }

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

@@ -75,6 +75,7 @@ import static org.briarproject.bramble.api.plugin.Plugin.State.ENABLING;
 import static org.briarproject.bramble.api.plugin.Plugin.State.INACTIVE;
 import static org.briarproject.bramble.api.plugin.TorConstants.CONTROL_PORT;
 import static org.briarproject.bramble.api.plugin.TorConstants.ID;
+import static org.briarproject.bramble.api.plugin.TorConstants.PREF_TOR_ENABLE;
 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_AUTOMATIC;
@@ -87,7 +88,6 @@ import static org.briarproject.bramble.api.plugin.TorConstants.PROP_ONION_V3;
 import static org.briarproject.bramble.api.plugin.TorConstants.REASON_BATTERY;
 import static org.briarproject.bramble.api.plugin.TorConstants.REASON_COUNTRY_BLOCKED;
 import static org.briarproject.bramble.api.plugin.TorConstants.REASON_MOBILE_DATA;
-import static org.briarproject.bramble.api.plugin.TorConstants.REASON_USER;
 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;
@@ -200,7 +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())
@@ -288,6 +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_TOR_ENABLE, false);
+			callback.mergeSettings(settings);
+		}
+		return settings;
+	}
+
 	private boolean assetsAreUpToDate() {
 		return doneFile.lastModified() > getLastUpdateTime();
 	}
@@ -763,6 +775,7 @@ abstract class TorPlugin implements DuplexPlugin, EventHandler, EventListener {
 			String country = locationUtils.getCurrentCountry();
 			boolean blocked =
 					circumventionProvider.isTorProbablyBlocked(country);
+			boolean enabledByUser = settings.getBoolean(PREF_TOR_ENABLE, true);
 			int network = settings.getInt(PREF_TOR_NETWORK,
 					PREF_TOR_NETWORK_AUTOMATIC);
 			boolean useMobile = settings.getBoolean(PREF_TOR_MOBILE, true);
@@ -785,7 +798,7 @@ abstract class TorPlugin implements DuplexPlugin, EventHandler, EventListener {
 
 			if (!online) {
 				LOG.info("Disabling network, device is offline");
-			} else if (network == PREF_TOR_NETWORK_NEVER) {
+			} else if (!enabledByUser) {
 				LOG.info("Disabling network, user has disabled Tor");
 				disabledBySettings = true;
 				reasonDisabled = REASON_USER;
@@ -870,11 +883,11 @@ abstract class TorPlugin implements DuplexPlugin, EventHandler, EventListener {
 			callback.pluginStateChanged(getState());
 		}
 
+		// Doesn't affect getState()
 		synchronized void setTorStarted() {
 			torStarted = true;
 		}
 
-		@SuppressWarnings("BooleanMethodIsAlwaysInverted")
 		synchronized boolean isTorRunning() {
 			return torStarted && !stopped;
 		}
@@ -914,12 +927,14 @@ abstract class TorPlugin implements DuplexPlugin, EventHandler, EventListener {
 			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;
 		}

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

@@ -34,6 +34,7 @@ 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.TcpConstants.PREF_TCP_ENABLE;
 import static org.junit.Assert.assertEquals;
 import static org.junit.Assert.assertFalse;
 import static org.junit.Assert.assertNotNull;
@@ -345,10 +346,15 @@ public class LanTcpPluginTest extends BrambleTestCase {
 		private final CountDownLatch propertiesLatch = new CountDownLatch(1);
 		private final CountDownLatch connectionsLatch = new CountDownLatch(1);
 		private final TransportProperties local = new TransportProperties();
+		private final Settings settings = new Settings();
+
+		private Callback() {
+			settings.putBoolean(PREF_TCP_ENABLE, true);
+		}
 
 		@Override
 		public Settings getSettings() {
-			return new Settings();
+			return settings;
 		}
 
 		@Override

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);

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 +8,23 @@ import android.content.IntentFilter;
 import android.os.Bundle;
 import android.view.MenuItem;
 
+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.IoExecutor;
 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.TransportId;
 import org.briarproject.bramble.api.plugin.event.BluetoothEnabledEvent;
+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.briar.R;
 import org.briarproject.briar.android.activity.ActivityComponent;
 import org.briarproject.briar.android.activity.BriarActivity;
@@ -21,6 +34,7 @@ import org.briarproject.briar.android.keyagreement.IntroFragment.IntroScreenSeen
 import org.briarproject.briar.android.keyagreement.KeyAgreementFragment.KeyAgreementEventListener;
 import org.briarproject.briar.android.util.UiUtils;
 
+import java.util.concurrent.Executor;
 import java.util.logging.Logger;
 
 import javax.annotation.Nullable;
@@ -37,13 +51,18 @@ 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.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.PREF_BT_ENABLE;
+import static org.briarproject.bramble.api.plugin.Plugin.State.ACTIVE;
+import static org.briarproject.bramble.api.plugin.Plugin.State.DISABLED;
+import static org.briarproject.bramble.api.plugin.Plugin.State.INACTIVE;
+import static org.briarproject.bramble.api.plugin.TcpConstants.PREF_TCP_ENABLE;
+import static org.briarproject.bramble.util.LogUtils.logException;
 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 +70,33 @@ 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 +104,21 @@ 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;
+
+	@Inject
+	@IoExecutor
+	Executor ioExecutor;
+
+	@Inject
+	SettingsManager settingsManager;
+
 	/**
 	 * Set to true in onPostResume() and false in onPause(). This prevents the
 	 * QR code fragment from being shown if onRequestPermissionsResult() is
@@ -74,21 +126,36 @@ 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 +163,17 @@ 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 +186,17 @@ 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 +213,22 @@ 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;
+					enablePlugin(LanTcpConstants.ID, PREF_TCP_ENABLE);
+				}
+				if (bluetoothDecision == BluetoothDecision.UNKNOWN) {
+					requestBluetoothDiscoverable();
+				} else if (shouldEnableBluetooth()) {
+					LOG.info("Enabling Bluetooth plugin");
+					hasEnabledBluetooth = true;
+					enablePlugin(BluetoothConstants.ID, PREF_BT_ENABLE);
+				}
 			}
 		}
 	}
@@ -167,57 +241,116 @@ 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);
+		return p != null && p.getState() == DISABLED;
+	}
+
+	private void enablePlugin(TransportId t, String settingKey) {
+		ioExecutor.execute(() -> {
+			try {
+				Settings s = new Settings();
+				s.putBoolean(settingKey, true);
+				settingsManager.mergeSettings(s, t.getString());
+			} catch (DbException e) {
+				logException(LOG, WARNING, e);
+			}
+		});
+	}
+
+	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);
+		return p != null && p.getState() == 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 +360,12 @@ 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 +377,6 @@ 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 +467,30 @@ 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/settings/SettingsFragment.java

@@ -21,6 +21,7 @@ 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.TorConstants;
 import org.briarproject.bramble.api.settings.Settings;
 import org.briarproject.bramble.api.settings.SettingsManager;
@@ -73,6 +74,8 @@ import static androidx.core.view.ViewCompat.LAYOUT_DIRECTION_LTR;
 import static java.util.logging.Level.INFO;
 import static java.util.logging.Level.WARNING;
 import static org.briarproject.bramble.api.plugin.BluetoothConstants.PREF_BT_ENABLE;
+import static org.briarproject.bramble.api.plugin.TcpConstants.PREF_TCP_ENABLE;
+import static org.briarproject.bramble.api.plugin.TorConstants.PREF_TOR_ENABLE;
 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_AUTOMATIC;
@@ -105,16 +108,24 @@ public class SettingsFragment extends PreferenceFragmentCompat
 		implements EventListener, OnPreferenceChangeListener {
 
 	public static final String SETTINGS_NAMESPACE = "android-ui";
-	public static final String BT_NAMESPACE = BluetoothConstants.ID.getString();
-	public static final String TOR_NAMESPACE = TorConstants.ID.getString();
 	public static final String LANGUAGE = "pref_key_language";
 	public static final String PREF_SCREEN_LOCK = "pref_key_lock";
 	public static final String PREF_SCREEN_LOCK_TIMEOUT =
 			"pref_key_lock_timeout";
 	public static final String NOTIFY_SIGN_IN = "pref_key_notify_sign_in";
-	public static final String TOR_NETWORK = "pref_key_tor_network";
-	public static final String TOR_MOBILE = "pref_key_tor_mobile_data";
-	public static final String TOR_ONLY_WHEN_CHARGING =
+
+	private static final String BT_NAMESPACE =
+			BluetoothConstants.ID.getString();
+	private static final String BT_ENABLE = "pref_key_bluetooth";
+
+	private static final String WIFI_NAMESPACE = LanTcpConstants.ID.getString();
+	private static final String WIFI_ENABLE = "pref_key_wifi";
+
+	private static final String TOR_NAMESPACE = TorConstants.ID.getString();
+	private static final String TOR_ENABLE = "pref_key_tor_enable";
+	private static final String TOR_NETWORK = "pref_key_tor_network";
+	private static final String TOR_MOBILE = "pref_key_tor_mobile_data";
+	private static final String TOR_ONLY_WHEN_CHARGING =
 			"pref_key_tor_only_when_charging";
 
 	private static final Logger LOG =
@@ -122,7 +133,9 @@ public class SettingsFragment extends PreferenceFragmentCompat
 
 	private SettingsActivity listener;
 	private ListPreference language;
-	private ListPreference enableBluetooth;
+	private SwitchPreference enableBluetooth;
+	private SwitchPreference enableWifi;
+	private SwitchPreference enableTor;
 	private ListPreference torNetwork;
 	private SwitchPreference torMobile;
 	private SwitchPreference torOnlyWhenCharging;
@@ -137,7 +150,7 @@ public class SettingsFragment extends PreferenceFragmentCompat
 	private Preference notifySound;
 
 	// Fields that are accessed from background threads must be volatile
-	private volatile Settings settings, btSettings, torSettings;
+	private volatile Settings settings, btSettings, wifiSettings, torSettings;
 	private volatile boolean settingsLoaded = false;
 
 	@Inject
@@ -163,28 +176,23 @@ public class SettingsFragment extends PreferenceFragmentCompat
 	public void onCreatePreferences(Bundle bundle, String s) {
 		addPreferencesFromResource(R.xml.settings);
 
-		language = (ListPreference) findPreference(LANGUAGE);
+		language = findPreference(LANGUAGE);
 		setLanguageEntries();
-		ListPreference theme =
-				(ListPreference) findPreference("pref_key_theme");
-		enableBluetooth = (ListPreference) findPreference("pref_key_bluetooth");
-		torNetwork = (ListPreference) findPreference(TOR_NETWORK);
-		torMobile = (SwitchPreference) findPreference(TOR_MOBILE);
-		torOnlyWhenCharging =
-				(SwitchPreference) findPreference(TOR_ONLY_WHEN_CHARGING);
-		screenLock = (SwitchPreference) findPreference(PREF_SCREEN_LOCK);
-		screenLockTimeout =
-				(ListPreference) findPreference(PREF_SCREEN_LOCK_TIMEOUT);
-		notifyPrivateMessages = (SwitchPreference) findPreference(
-				"pref_key_notify_private_messages");
-		notifyGroupMessages = (SwitchPreference) findPreference(
-				"pref_key_notify_group_messages");
-		notifyForumPosts = (SwitchPreference) findPreference(
-				"pref_key_notify_forum_posts");
-		notifyBlogPosts = (SwitchPreference) findPreference(
-				"pref_key_notify_blog_posts");
-		notifyVibration = (SwitchPreference) findPreference(
-				"pref_key_notify_vibration");
+		ListPreference theme = findPreference("pref_key_theme");
+		enableBluetooth = findPreference(BT_ENABLE);
+		enableWifi = findPreference(WIFI_ENABLE);
+		enableTor = findPreference(TOR_ENABLE);
+		torNetwork = findPreference(TOR_NETWORK);
+		torMobile = findPreference(TOR_MOBILE);
+		torOnlyWhenCharging = findPreference(TOR_ONLY_WHEN_CHARGING);
+		screenLock = findPreference(PREF_SCREEN_LOCK);
+		screenLockTimeout = findPreference(PREF_SCREEN_LOCK_TIMEOUT);
+		notifyPrivateMessages =
+				findPreference("pref_key_notify_private_messages");
+		notifyGroupMessages = findPreference("pref_key_notify_group_messages");
+		notifyForumPosts = findPreference("pref_key_notify_forum_posts");
+		notifyBlogPosts = findPreference("pref_key_notify_blog_posts");
+		notifyVibration = findPreference("pref_key_notify_vibration");
 		notifySound = findPreference("pref_key_notify_sound");
 
 		language.setOnPreferenceChangeListener(this);
@@ -194,8 +202,7 @@ public class SettingsFragment extends PreferenceFragmentCompat
 				UiUtils.setTheme(getActivity(), (String) newValue);
 				// bring up parent activity, so it can change its theme as well
 				// upstream bug: https://issuetracker.google.com/issues/38352704
-				Intent intent =
-						new Intent(getActivity(), ENTRY_ACTIVITY);
+				Intent intent = new Intent(getActivity(), ENTRY_ACTIVITY);
 				intent.setFlags(
 						FLAG_ACTIVITY_CLEAR_TASK | FLAG_ACTIVITY_NEW_TASK);
 				startActivity(intent);
@@ -207,6 +214,8 @@ public class SettingsFragment extends PreferenceFragmentCompat
 			return true;
 		});
 		enableBluetooth.setOnPreferenceChangeListener(this);
+		enableWifi.setOnPreferenceChangeListener(this);
+		enableTor.setOnPreferenceChangeListener(this);
 		torNetwork.setOnPreferenceChangeListener(this);
 		torMobile.setOnPreferenceChangeListener(this);
 		torOnlyWhenCharging.setOnPreferenceChangeListener(this);
@@ -335,7 +344,8 @@ public class SettingsFragment extends PreferenceFragmentCompat
 		boolean blocked =
 				circumventionProvider.isTorProbablyBlocked(country);
 		boolean useBridges = circumventionProvider.doBridgesWork(country);
-		String setting = getString(R.string.tor_network_setting_without_bridges);
+		String setting =
+				getString(R.string.tor_network_setting_without_bridges);
 		if (blocked && useBridges) {
 			setting = getString(R.string.tor_network_setting_with_bridges);
 		} else if (blocked) {
@@ -352,6 +362,7 @@ public class SettingsFragment extends PreferenceFragmentCompat
 				long start = now();
 				settings = settingsManager.getSettings(SETTINGS_NAMESPACE);
 				btSettings = settingsManager.getSettings(BT_NAMESPACE);
+				wifiSettings = settingsManager.getSettings(WIFI_NAMESPACE);
 				torSettings = settingsManager.getSettings(TOR_NAMESPACE);
 				settingsLoaded = true;
 				logDuration(LOG, "Loading settings", start);
@@ -369,7 +380,15 @@ public class SettingsFragment extends PreferenceFragmentCompat
 
 			boolean btEnabledSetting =
 					btSettings.getBoolean(PREF_BT_ENABLE, false);
-			enableBluetooth.setValue(Boolean.toString(btEnabledSetting));
+			enableBluetooth.setChecked(btEnabledSetting);
+
+			boolean wifiEnabledSetting =
+					wifiSettings.getBoolean(PREF_TCP_ENABLE, false);
+			enableWifi.setChecked(wifiEnabledSetting);
+
+			boolean torEnabledSetting =
+					torSettings.getBoolean(PREF_TOR_ENABLE, true);
+			enableTor.setChecked(torEnabledSetting);
 
 			int torNetworkSetting = torSettings.getInt(PREF_TOR_NETWORK,
 					PREF_TOR_NETWORK_AUTOMATIC);
@@ -443,6 +462,8 @@ public class SettingsFragment extends PreferenceFragmentCompat
 		// - pref_key_lock (screenLock -> displayScreenLockSetting())
 		// - pref_key_lock_timeout (screenLockTimeout)
 		enableBluetooth.setEnabled(enabled);
+		enableWifi.setEnabled(enabled);
+		enableTor.setEnabled(enabled);
 		torNetwork.setEnabled(enabled);
 		torMobile.setEnabled(enabled);
 		torOnlyWhenCharging.setEnabled(enabled);
@@ -545,8 +566,14 @@ public class SettingsFragment extends PreferenceFragmentCompat
 				languageChanged((String) newValue);
 			return false;
 		} else if (preference == enableBluetooth) {
-			boolean btSetting = Boolean.valueOf((String) newValue);
-			storeBluetoothSettings(btSetting);
+			boolean btSetting = (Boolean) newValue;
+			storeBluetoothSetting(btSetting);
+		} else if (preference == enableWifi) {
+			boolean wifiSetting = (Boolean) newValue;
+			storeWifiSetting(wifiSetting);
+		} else if (preference == enableTor) {
+			boolean torEnabledSetting = (Boolean) newValue;
+			storeTorEnabledSetting(torEnabledSetting);
 		} else if (preference == torNetwork) {
 			int torNetworkSetting = Integer.valueOf((String) newValue);
 			storeTorNetworkSetting(torNetworkSetting);
@@ -610,6 +637,12 @@ public class SettingsFragment extends PreferenceFragmentCompat
 		builder.show();
 	}
 
+	private void storeTorEnabledSetting(boolean torEnabledSetting) {
+		Settings s = new Settings();
+		s.putBoolean(PREF_TOR_ENABLE, torEnabledSetting);
+		mergeSettings(s, TOR_NAMESPACE);
+	}
+
 	private void storeTorNetworkSetting(int torNetworkSetting) {
 		Settings s = new Settings();
 		s.putInt(PREF_TOR_NETWORK, torNetworkSetting);
@@ -628,12 +661,18 @@ public class SettingsFragment extends PreferenceFragmentCompat
 		mergeSettings(s, TOR_NAMESPACE);
 	}
 
-	private void storeBluetoothSettings(boolean btSetting) {
+	private void storeBluetoothSetting(boolean btSetting) {
 		Settings s = new Settings();
 		s.putBoolean(PREF_BT_ENABLE, btSetting);
 		mergeSettings(s, BT_NAMESPACE);
 	}
 
+	private void storeWifiSetting(boolean wifiSetting) {
+		Settings s = new Settings();
+		s.putBoolean(PREF_TCP_ENABLE, wifiSetting);
+		mergeSettings(s, WIFI_NAMESPACE);
+	}
+
 	private void storeSettings(Settings s) {
 		mergeSettings(s, SETTINGS_NAMESPACE);
 	}
@@ -696,6 +735,10 @@ public class SettingsFragment extends PreferenceFragmentCompat
 				LOG.info("Bluetooth settings updated");
 				btSettings = s.getSettings();
 				displaySettings();
+			} else if (namespace.equals(WIFI_NAMESPACE)) {
+				LOG.info("Wifi settings updated");
+				wifiSettings = s.getSettings();
+				displaySettings();
 			} else if (namespace.equals(TOR_NAMESPACE)) {
 				LOG.info("Tor settings updated");
 				torSettings = s.getSettings();

briar-android/src/main/res/values/arrays.xml

@@ -1,14 +1,5 @@
 <?xml version="1.0" encoding="utf-8"?>
 <resources>
-	<string-array name="boolean_array">
-		<item>true</item>
-		<item>false</item>
-	</string-array>
-	<string-array name="bt_setting_names">
-		<item>@string/bluetooth_setting_enabled</item>
-		<item>@string/bluetooth_setting_disabled</item>
-	</string-array>
-
 	<string-array name="tor_network_setting_names">
 		<item>@string/tor_network_setting_automatic</item>
 		<item>@string/tor_network_setting_without_bridges</item>
@@ -66,6 +57,7 @@
 		<item>zh-CN</item>
 		<item>zh-TW</item>
 	</string-array>
+
 	<string-array name="pref_theme_entries">
 		<item>@string/pref_theme_light</item>
 		<item>@string/pref_theme_dark</item>

briar-android/src/main/res/values/strings.xml

@@ -441,12 +441,12 @@
 	<string name="pref_theme_auto">Automatic (Daytime)</string>
 	<string name="pref_theme_system">System Default</string>
 
-	<!-- Settings Network -->
-	<string name="network_settings_title">Networks</string>
-	<string name="bluetooth_setting">Connect via Bluetooth</string>
-	<string name="bluetooth_setting_enabled">Whenever contacts are nearby</string>
-	<string name="bluetooth_setting_disabled">Only when adding contacts</string>
-	<string name="tor_network_setting">Connect via Internet (Tor)</string>
+	<!-- Settings Connections -->
+	<string name="network_settings_title">Connections</string>
+	<string name="bluetooth_setting">Connect to contacts via Bluetooth</string>
+	<string name="wifi_setting">Connect to contacts on the same Wi-Fi network</string>
+	<string name="tor_enable_title">Connect to contacts via Internet (Tor)</string>
+	<string name="tor_network_setting">Connection method for Internet (Tor)</string>
 	<string name="tor_network_setting_automatic">Automatic based on location</string>
 	<string name="tor_network_setting_without_bridges">Use Tor without bridges</string>
 	<string name="tor_network_setting_with_bridges">Use Tor with bridges</string>

briar-android/src/main/res/xml/settings.xml

@@ -29,18 +29,33 @@
 		android:layout="@layout/preferences_category"
 		android:title="@string/network_settings_title">
 
-		<ListPreference
+		<SwitchPreference
 			android:defaultValue="false"
-			android:entries="@array/bt_setting_names"
-			android:entryValues="@array/boolean_array"
 			android:key="pref_key_bluetooth"
 			android:persistent="false"
-			android:summary="%s"
 			android:title="@string/bluetooth_setting"
+			android:widgetLayout="@layout/preference_switch_compat"
+			app:iconSpaceReserved="false"/>
+
+		<SwitchPreference
+			android:defaultValue="false"
+			android:key="pref_key_wifi"
+			android:persistent="false"
+			android:title="@string/wifi_setting"
+			android:widgetLayout="@layout/preference_switch_compat"
+			app:iconSpaceReserved="false"/>
+
+		<SwitchPreference
+			android:defaultValue="true"
+			android:key="pref_key_tor_enable"
+			android:persistent="false"
+			android:title="@string/tor_enable_title"
+			android:widgetLayout="@layout/preference_switch_compat"
 			app:iconSpaceReserved="false"/>
 
 		<ListPreference
 			android:defaultValue="0"
+			android:dependency="pref_key_tor_enable"
 			android:entries="@array/tor_network_setting_names"
 			android:entryValues="@array/tor_network_setting_values"
 			android:key="pref_key_tor_network"
@@ -51,6 +66,7 @@
 
 		<SwitchPreference
 			android:defaultValue="true"
+			android:dependency="pref_key_tor_enable"
 			android:key="pref_key_tor_mobile_data"
 			android:persistent="false"
 			android:title="@string/tor_mobile_data_title"
@@ -59,6 +75,7 @@
 
 		<SwitchPreference
 			android:defaultValue="false"
+			android:dependency="pref_key_tor_enable"
 			android:key="pref_key_tor_only_when_charging"
 			android:persistent="false"
 			android:title="@string/tor_only_when_charging_title"