Poll Tor plugin infrequently once our HS is reachable.

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

@@ -12,7 +12,6 @@ import android.content.IntentFilter;
 import org.briarproject.bramble.api.io.TimeoutMonitor;
 import org.briarproject.bramble.api.nullsafety.MethodsNotNullByDefault;
 import org.briarproject.bramble.api.nullsafety.ParametersNotNullByDefault;
-import org.briarproject.bramble.api.plugin.Backoff;
 import org.briarproject.bramble.api.plugin.PluginCallback;
 import org.briarproject.bramble.api.plugin.PluginException;
 import org.briarproject.bramble.api.plugin.duplex.DuplexTransportConnection;
@@ -82,10 +81,10 @@ class AndroidBluetoothPlugin extends BluetoothPlugin<BluetoothServerSocket> {
 			TimeoutMonitor timeoutMonitor, Executor ioExecutor,
 			SecureRandom secureRandom, ScheduledExecutorService scheduler,
 			AndroidExecutor androidExecutor, Context appContext, Clock clock,
-			Backoff backoff, PluginCallback callback, int maxLatency,
-			int maxIdleTime) {
+			PluginCallback callback, int maxLatency, int maxIdleTime,
+			int pollingInterval) {
 		super(connectionLimiter, timeoutMonitor, ioExecutor, secureRandom,
-				backoff, callback, maxLatency, maxIdleTime);
+				callback, maxLatency, maxIdleTime, pollingInterval);
 		this.scheduler = scheduler;
 		this.androidExecutor = androidExecutor;
 		this.appContext = appContext;

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

@@ -5,8 +5,6 @@ import android.content.Context;
 import org.briarproject.bramble.api.event.EventBus;
 import org.briarproject.bramble.api.io.TimeoutMonitor;
 import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
-import org.briarproject.bramble.api.plugin.Backoff;
-import org.briarproject.bramble.api.plugin.BackoffFactory;
 import org.briarproject.bramble.api.plugin.PluginCallback;
 import org.briarproject.bramble.api.plugin.TransportId;
 import org.briarproject.bramble.api.plugin.duplex.DuplexPlugin;
@@ -20,17 +18,17 @@ import java.util.concurrent.ScheduledExecutorService;
 
 import javax.annotation.concurrent.Immutable;
 
+import static java.util.concurrent.TimeUnit.MINUTES;
+import static java.util.concurrent.TimeUnit.SECONDS;
 import static org.briarproject.bramble.api.plugin.BluetoothConstants.ID;
 
 @Immutable
 @NotNullByDefault
 public class AndroidBluetoothPluginFactory implements DuplexPluginFactory {
 
-	private static final int MAX_LATENCY = 30 * 1000; // 30 seconds
-	private static final int MAX_IDLE_TIME = 30 * 1000; // 30 seconds
-	private static final int MIN_POLLING_INTERVAL = 60 * 1000; // 1 minute
-	private static final int MAX_POLLING_INTERVAL = 10 * 60 * 1000; // 10 mins
-	private static final double BACKOFF_BASE = 1.2;
+	private static final int MAX_LATENCY = (int) SECONDS.toMillis(30);
+	private static final int MAX_IDLE_TIME = (int) SECONDS.toMillis(30);
+	private static final int POLLING_INTERVAL = (int) MINUTES.toMillis(2);
 
 	private final Executor ioExecutor;
 	private final ScheduledExecutorService scheduler;
@@ -40,13 +38,12 @@ public class AndroidBluetoothPluginFactory implements DuplexPluginFactory {
 	private final EventBus eventBus;
 	private final Clock clock;
 	private final TimeoutMonitor timeoutMonitor;
-	private final BackoffFactory backoffFactory;
 
 	public AndroidBluetoothPluginFactory(Executor ioExecutor,
 			ScheduledExecutorService scheduler,
 			AndroidExecutor androidExecutor, Context appContext,
 			SecureRandom secureRandom, EventBus eventBus, Clock clock,
-			TimeoutMonitor timeoutMonitor, BackoffFactory backoffFactory) {
+			TimeoutMonitor timeoutMonitor) {
 		this.ioExecutor = ioExecutor;
 		this.scheduler = scheduler;
 		this.androidExecutor = androidExecutor;
@@ -55,7 +52,6 @@ public class AndroidBluetoothPluginFactory implements DuplexPluginFactory {
 		this.eventBus = eventBus;
 		this.clock = clock;
 		this.timeoutMonitor = timeoutMonitor;
-		this.backoffFactory = backoffFactory;
 	}
 
 	@Override
@@ -72,12 +68,10 @@ public class AndroidBluetoothPluginFactory implements DuplexPluginFactory {
 	public DuplexPlugin createPlugin(PluginCallback callback) {
 		BluetoothConnectionLimiter connectionLimiter =
 				new BluetoothConnectionLimiterImpl(eventBus);
-		Backoff backoff = backoffFactory.createBackoff(MIN_POLLING_INTERVAL,
-				MAX_POLLING_INTERVAL, BACKOFF_BASE);
 		AndroidBluetoothPlugin plugin = new AndroidBluetoothPlugin(
 				connectionLimiter, timeoutMonitor, ioExecutor, secureRandom,
-				scheduler, androidExecutor, appContext, clock, backoff,
-				callback, MAX_LATENCY, MAX_IDLE_TIME);
+				scheduler, androidExecutor, appContext, clock, callback,
+				MAX_LATENCY, MAX_IDLE_TIME, POLLING_INTERVAL);
 		eventBus.addListener(plugin);
 		return plugin;
 	}

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

@@ -15,7 +15,6 @@ import org.briarproject.bramble.api.Pair;
 import org.briarproject.bramble.api.event.Event;
 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;
 
@@ -62,9 +61,9 @@ class AndroidLanTcpPlugin extends LanTcpPlugin {
 	private volatile SocketFactory socketFactory;
 
 	AndroidLanTcpPlugin(Executor ioExecutor, Context appContext,
-			Backoff backoff, PluginCallback callback, int maxLatency,
-			int maxIdleTime, int connectionTimeout) {
-		super(ioExecutor, backoff, callback, maxLatency, maxIdleTime,
+			PluginCallback callback, int maxLatency, int maxIdleTime,
+			int pollingInterval, int connectionTimeout) {
+		super(ioExecutor, callback, maxLatency, maxIdleTime, pollingInterval,
 				connectionTimeout);
 		// Don't execute more than one connection status check at a time
 		connectionStatusExecutor =

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

@@ -4,8 +4,6 @@ import android.content.Context;
 
 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;
 import org.briarproject.bramble.api.plugin.PluginCallback;
 import org.briarproject.bramble.api.plugin.TransportId;
 import org.briarproject.bramble.api.plugin.duplex.DuplexPlugin;
@@ -15,29 +13,27 @@ import java.util.concurrent.Executor;
 
 import javax.annotation.concurrent.Immutable;
 
+import static java.util.concurrent.TimeUnit.MINUTES;
+import static java.util.concurrent.TimeUnit.SECONDS;
 import static org.briarproject.bramble.api.plugin.LanTcpConstants.ID;
 
 @Immutable
 @NotNullByDefault
 public class AndroidLanTcpPluginFactory implements DuplexPluginFactory {
 
-	private static final int MAX_LATENCY = 30_000; // 30 seconds
-	private static final int MAX_IDLE_TIME = 30_000; // 30 seconds
-	private static final int CONNECTION_TIMEOUT = 3_000; // 3 seconds
-	private static final int MIN_POLLING_INTERVAL = 60_000; // 1 minute
-	private static final int MAX_POLLING_INTERVAL = 600_000; // 10 mins
-	private static final double BACKOFF_BASE = 1.2;
+	private static final int MAX_LATENCY = (int) SECONDS.toMillis(30);
+	private static final int MAX_IDLE_TIME = (int) SECONDS.toMillis(30);
+	private static final int POLLING_INTERVAL = (int) MINUTES.toMillis(1);
+	private static final int CONNECTION_TIMEOUT = (int) SECONDS.toMillis(3);
 
 	private final Executor ioExecutor;
 	private final EventBus eventBus;
-	private final BackoffFactory backoffFactory;
 	private final Context appContext;
 
 	public AndroidLanTcpPluginFactory(Executor ioExecutor, EventBus eventBus,
-			BackoffFactory backoffFactory, Context appContext) {
+			Context appContext) {
 		this.ioExecutor = ioExecutor;
 		this.eventBus = eventBus;
-		this.backoffFactory = backoffFactory;
 		this.appContext = appContext;
 	}
 
@@ -53,11 +49,9 @@ public class AndroidLanTcpPluginFactory implements DuplexPluginFactory {
 
 	@Override
 	public DuplexPlugin createPlugin(PluginCallback callback) {
-		Backoff backoff = backoffFactory.createBackoff(MIN_POLLING_INTERVAL,
-				MAX_POLLING_INTERVAL, BACKOFF_BASE);
 		AndroidLanTcpPlugin plugin = new AndroidLanTcpPlugin(ioExecutor,
-				appContext, backoff, callback, MAX_LATENCY, MAX_IDLE_TIME,
-				CONNECTION_TIMEOUT);
+				appContext, callback, MAX_LATENCY, MAX_IDLE_TIME,
+				POLLING_INTERVAL, CONNECTION_TIMEOUT);
 		eventBus.addListener(plugin);
 		return plugin;
 	}

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

@@ -10,7 +10,6 @@ import org.briarproject.bramble.api.battery.BatteryManager;
 import org.briarproject.bramble.api.network.NetworkManager;
 import org.briarproject.bramble.api.nullsafety.MethodsNotNullByDefault;
 import org.briarproject.bramble.api.nullsafety.ParametersNotNullByDefault;
-import org.briarproject.bramble.api.plugin.Backoff;
 import org.briarproject.bramble.api.plugin.PluginCallback;
 import org.briarproject.bramble.api.system.Clock;
 import org.briarproject.bramble.api.system.LocationUtils;
@@ -41,13 +40,15 @@ class AndroidTorPlugin extends TorPlugin {
 			LocationUtils locationUtils, SocketFactory torSocketFactory,
 			Clock clock, ResourceProvider resourceProvider,
 			CircumventionProvider circumventionProvider,
-			BatteryManager batteryManager, Backoff backoff,
+			BatteryManager batteryManager,
 			TorRendezvousCrypto torRendezvousCrypto,
 			PluginCallback callback, String architecture, int maxLatency,
-			int maxIdleTime) {
+			int maxIdleTime, int initialPollingInterval,
+			int stablePollingInterval) {
 		super(ioExecutor, networkManager, locationUtils, torSocketFactory,
 				clock, resourceProvider, circumventionProvider, batteryManager,
-				backoff, torRendezvousCrypto, callback, architecture, maxLatency, maxIdleTime,
+				torRendezvousCrypto, callback, architecture, maxLatency,
+				maxIdleTime, initialPollingInterval, stablePollingInterval,
 				appContext.getDir("tor", MODE_PRIVATE));
 		this.appContext = appContext;
 		PowerManager pm = (PowerManager)

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

@@ -6,8 +6,6 @@ import org.briarproject.bramble.api.battery.BatteryManager;
 import org.briarproject.bramble.api.event.EventBus;
 import org.briarproject.bramble.api.network.NetworkManager;
 import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
-import org.briarproject.bramble.api.plugin.Backoff;
-import org.briarproject.bramble.api.plugin.BackoffFactory;
 import org.briarproject.bramble.api.plugin.PluginCallback;
 import org.briarproject.bramble.api.plugin.TorConstants;
 import org.briarproject.bramble.api.plugin.TransportId;
@@ -25,18 +23,33 @@ import java.util.logging.Logger;
 import javax.annotation.concurrent.Immutable;
 import javax.net.SocketFactory;
 
+import static java.util.concurrent.TimeUnit.MINUTES;
+import static java.util.concurrent.TimeUnit.SECONDS;
+import static java.util.logging.Logger.getLogger;
+
 @Immutable
 @NotNullByDefault
 public class AndroidTorPluginFactory implements DuplexPluginFactory {
 
 	private static final Logger LOG =
-			Logger.getLogger(AndroidTorPluginFactory.class.getName());
+			getLogger(AndroidTorPluginFactory.class.getName());
 
-	private static final int MAX_LATENCY = 30 * 1000; // 30 seconds
-	private static final int MAX_IDLE_TIME = 30 * 1000; // 30 seconds
-	private static final int MIN_POLLING_INTERVAL = 60 * 1000; // 1 minute
-	private static final int MAX_POLLING_INTERVAL = 10 * 60 * 1000; // 10 mins
-	private static final double BACKOFF_BASE = 1.2;
+	private static final int MAX_LATENCY = (int) SECONDS.toMillis(30);
+	private static final int MAX_IDLE_TIME = (int) SECONDS.toMillis(30);
+
+	/**
+	 * How often to poll before our hidden service becomes reachable.
+	 */
+	private static final int INITIAL_POLLING_INTERVAL =
+			(int) MINUTES.toMillis(1);
+
+	/**
+	 * How often to poll when our hidden service is reachable. Our contacts
+	 * will poll when they come online, so our polling is just a fallback in
+	 * case of repeated connection failures.
+	 */
+	private static final int STABLE_POLLING_INTERVAL =
+			(int) MINUTES.toMillis(15);
 
 	private final Executor ioExecutor;
 	private final ScheduledExecutorService scheduler;
@@ -45,7 +58,6 @@ public class AndroidTorPluginFactory implements DuplexPluginFactory {
 	private final LocationUtils locationUtils;
 	private final EventBus eventBus;
 	private final SocketFactory torSocketFactory;
-	private final BackoffFactory backoffFactory;
 	private final ResourceProvider resourceProvider;
 	private final CircumventionProvider circumventionProvider;
 	private final BatteryManager batteryManager;
@@ -55,7 +67,7 @@ public class AndroidTorPluginFactory implements DuplexPluginFactory {
 			ScheduledExecutorService scheduler, Context appContext,
 			NetworkManager networkManager, LocationUtils locationUtils,
 			EventBus eventBus, SocketFactory torSocketFactory,
-			BackoffFactory backoffFactory, ResourceProvider resourceProvider,
+			ResourceProvider resourceProvider,
 			CircumventionProvider circumventionProvider,
 			BatteryManager batteryManager, Clock clock) {
 		this.ioExecutor = ioExecutor;
@@ -65,7 +77,6 @@ public class AndroidTorPluginFactory implements DuplexPluginFactory {
 		this.locationUtils = locationUtils;
 		this.eventBus = eventBus;
 		this.torSocketFactory = torSocketFactory;
-		this.backoffFactory = backoffFactory;
 		this.resourceProvider = resourceProvider;
 		this.circumventionProvider = circumventionProvider;
 		this.batteryManager = batteryManager;
@@ -109,14 +120,13 @@ public class AndroidTorPluginFactory implements DuplexPluginFactory {
 		// Use position-independent executable
 		architecture += "_pie";
 
-		Backoff backoff = backoffFactory.createBackoff(MIN_POLLING_INTERVAL,
-				MAX_POLLING_INTERVAL, BACKOFF_BASE);
 		TorRendezvousCrypto torRendezvousCrypto = new TorRendezvousCryptoImpl();
 		AndroidTorPlugin plugin = new AndroidTorPlugin(ioExecutor, scheduler,
 				appContext, networkManager, locationUtils, torSocketFactory,
 				clock, resourceProvider, circumventionProvider, batteryManager,
-				backoff, torRendezvousCrypto, callback, architecture,
-				MAX_LATENCY, MAX_IDLE_TIME);
+				torRendezvousCrypto, callback, architecture, MAX_LATENCY,
+				MAX_IDLE_TIME, INITIAL_POLLING_INTERVAL,
+				STABLE_POLLING_INTERVAL);
 		eventBus.addListener(plugin);
 		return plugin;
 	}

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

@@ -1,22 +0,0 @@
-package org.briarproject.bramble.api.plugin;
-
-/**
- * Calculates polling intervals for transport plugins that use backoff.
- */
-public interface Backoff {
-
-	/**
-	 * Returns the current polling interval.
-	 */
-	int getPollingInterval();
-
-	/**
-	 * Increments the backoff counter.
-	 */
-	void increment();
-
-	/**
-	 * Resets the backoff counter.
-	 */
-	void reset();
-}

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

@@ -1,7 +0,0 @@
-package org.briarproject.bramble.api.plugin;
-
-public interface BackoffFactory {
-
-	Backoff createBackoff(int minInterval, int maxInterval,
-			double base);
-}

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

@@ -1,18 +0,0 @@
-package org.briarproject.bramble.plugin;
-
-import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
-import org.briarproject.bramble.api.plugin.Backoff;
-import org.briarproject.bramble.api.plugin.BackoffFactory;
-
-import javax.annotation.concurrent.Immutable;
-
-@Immutable
-@NotNullByDefault
-class BackoffFactoryImpl implements BackoffFactory {
-
-	@Override
-	public Backoff createBackoff(int minInterval, int maxInterval,
-			double base) {
-		return new BackoffImpl(minInterval, maxInterval, base);
-	}
-}

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

@@ -1,42 +0,0 @@
-package org.briarproject.bramble.plugin;
-
-import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
-import org.briarproject.bramble.api.plugin.Backoff;
-
-import java.util.concurrent.atomic.AtomicInteger;
-
-import javax.annotation.concurrent.ThreadSafe;
-
-@ThreadSafe
-@NotNullByDefault
-class BackoffImpl implements Backoff {
-
-	private final int minInterval, maxInterval;
-	private final double base;
-	private final AtomicInteger backoff;
-
-	BackoffImpl(int minInterval, int maxInterval, double base) {
-		this.minInterval = minInterval;
-		this.maxInterval = maxInterval;
-		this.base = base;
-		backoff = new AtomicInteger(0);
-	}
-
-	@Override
-	public int getPollingInterval() {
-		double multiplier = Math.pow(base, backoff.get());
-		// Large or infinite values will be rounded to Integer.MAX_VALUE
-		int interval = (int) (minInterval * multiplier);
-		return Math.min(interval, maxInterval);
-	}
-
-	@Override
-	public void increment() {
-		backoff.incrementAndGet();
-	}
-
-	@Override
-	public void reset() {
-		backoff.set(0);
-	}
-}

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

@@ -2,7 +2,6 @@ package org.briarproject.bramble.plugin;
 
 import org.briarproject.bramble.api.event.EventBus;
 import org.briarproject.bramble.api.lifecycle.LifecycleManager;
-import org.briarproject.bramble.api.plugin.BackoffFactory;
 import org.briarproject.bramble.api.plugin.PluginConfig;
 import org.briarproject.bramble.api.plugin.PluginManager;
 
@@ -22,11 +21,6 @@ public class PluginModule {
 		Poller poller;
 	}
 
-	@Provides
-	BackoffFactory provideBackoffFactory() {
-		return new BackoffFactoryImpl();
-	}
-
 	@Provides
 	@Singleton
 	PluginManager providePluginManager(LifecycleManager lifecycleManager,

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

@@ -19,7 +19,6 @@ 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.ConnectionClosedEvent;
-import org.briarproject.bramble.api.plugin.event.ConnectionOpenedEvent;
 import org.briarproject.bramble.api.plugin.event.TransportActiveEvent;
 import org.briarproject.bramble.api.plugin.event.TransportInactiveEvent;
 import org.briarproject.bramble.api.plugin.simplex.SimplexPlugin;
@@ -96,16 +95,10 @@ class PollerImpl implements Poller, EventListener {
 			connectToContact(c.getContactId());
 		} else if (e instanceof ConnectionClosedEvent) {
 			ConnectionClosedEvent c = (ConnectionClosedEvent) e;
-			// Reschedule polling, the polling interval may have decreased
-			reschedule(c.getTransportId());
 			// If an outgoing connection failed, try to reconnect
 			if (!c.isIncoming() && c.isException()) {
 				connectToContact(c.getContactId(), c.getTransportId());
 			}
-		} else if (e instanceof ConnectionOpenedEvent) {
-			ConnectionOpenedEvent c = (ConnectionOpenedEvent) e;
-			// Reschedule polling, the polling interval may have decreased
-			reschedule(c.getTransportId());
 		} else if (e instanceof TransportActiveEvent) {
 			TransportActiveEvent t = (TransportActiveEvent) e;
 			// Poll the newly activated transport
@@ -164,12 +157,6 @@ class PollerImpl implements Poller, EventListener {
 		});
 	}
 
-	private void reschedule(TransportId t) {
-		Plugin p = pluginManager.getPlugin(t);
-		if (p != null && p.shouldPoll())
-			schedule(p, p.getPollingInterval(), false);
-	}
-
 	private void pollNow(TransportId t) {
 		Plugin p = pluginManager.getPlugin(t);
 		// Randomise next polling interval

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

@@ -14,7 +14,6 @@ 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.PluginCallback;
 import org.briarproject.bramble.api.plugin.PluginException;
@@ -73,9 +72,8 @@ abstract class BluetoothPlugin<SS> implements DuplexPlugin, EventListener {
 
 	private final Executor ioExecutor;
 	private final SecureRandom secureRandom;
-	private final Backoff backoff;
 	private final PluginCallback callback;
-	private final int maxLatency, maxIdleTime;
+	private final int maxLatency, maxIdleTime, pollingInterval;
 	private final AtomicBoolean used = new AtomicBoolean(false);
 
 	protected final PluginState state = new PluginState();
@@ -116,16 +114,16 @@ abstract class BluetoothPlugin<SS> implements DuplexPlugin, EventListener {
 
 	BluetoothPlugin(BluetoothConnectionLimiter connectionLimiter,
 			TimeoutMonitor timeoutMonitor, Executor ioExecutor,
-			SecureRandom secureRandom, Backoff backoff,
-			PluginCallback callback, int maxLatency, int maxIdleTime) {
+			SecureRandom secureRandom, PluginCallback callback, int maxLatency, int maxIdleTime,
+			int pollingInterval) {
 		this.connectionLimiter = connectionLimiter;
 		this.timeoutMonitor = timeoutMonitor;
 		this.ioExecutor = ioExecutor;
 		this.secureRandom = secureRandom;
-		this.backoff = backoff;
 		this.callback = callback;
 		this.maxLatency = maxLatency;
 		this.maxIdleTime = maxIdleTime;
+		this.pollingInterval = pollingInterval;
 	}
 
 	void onAdapterEnabled() {
@@ -196,7 +194,6 @@ abstract class BluetoothPlugin<SS> implements DuplexPlugin, EventListener {
 				tryToClose(ss);
 				return;
 			}
-			backoff.reset();
 			acceptContactConnections(ss);
 		});
 	}
@@ -239,7 +236,6 @@ abstract class BluetoothPlugin<SS> implements DuplexPlugin, EventListener {
 			}
 			LOG.info("Connection received");
 			connectionLimiter.connectionOpened(conn);
-			backoff.reset();
 			callback.handleConnection(conn);
 		}
 	}
@@ -268,14 +264,13 @@ abstract class BluetoothPlugin<SS> implements DuplexPlugin, EventListener {
 
 	@Override
 	public int getPollingInterval() {
-		return backoff.getPollingInterval();
+		return pollingInterval;
 	}
 
 	@Override
 	public void poll(Collection<Pair<TransportProperties, ConnectionHandler>>
 			properties) {
 		if (getState() != ACTIVE) return;
-		backoff.increment();
 		for (Pair<TransportProperties, ConnectionHandler> p : properties) {
 			connect(p.getFirst(), p.getSecond());
 		}
@@ -288,10 +283,7 @@ abstract class BluetoothPlugin<SS> implements DuplexPlugin, EventListener {
 		if (isNullOrEmpty(uuid)) return;
 		ioExecutor.execute(() -> {
 			DuplexTransportConnection d = createConnection(p);
-			if (d != null) {
-				backoff.reset();
-				h.handleConnection(d);
-			}
+			if (d != null) h.handleConnection(d);
 		});
 	}
 

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

@@ -5,7 +5,6 @@ import org.briarproject.bramble.api.data.BdfList;
 import org.briarproject.bramble.api.keyagreement.KeyAgreementConnection;
 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.PluginCallback;
 import org.briarproject.bramble.api.plugin.TransportId;
 import org.briarproject.bramble.api.plugin.duplex.DuplexTransportConnection;
@@ -88,9 +87,9 @@ class LanTcpPlugin extends TcpPlugin {
 		}
 	}
 
-	LanTcpPlugin(Executor ioExecutor, Backoff backoff, PluginCallback callback,
-			int maxLatency, int maxIdleTime, int connectionTimeout) {
-		super(ioExecutor, backoff, callback, maxLatency, maxIdleTime,
+	LanTcpPlugin(Executor ioExecutor, PluginCallback callback, int maxLatency,
+			int maxIdleTime, int pollingInterval, int connectionTimeout) {
+		super(ioExecutor, callback, maxLatency, maxIdleTime, pollingInterval,
 				connectionTimeout);
 	}
 

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

@@ -2,8 +2,6 @@ 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;
 import org.briarproject.bramble.api.plugin.PluginCallback;
 import org.briarproject.bramble.api.plugin.TransportId;
 import org.briarproject.bramble.api.plugin.duplex.DuplexPlugin;
@@ -13,28 +11,25 @@ import java.util.concurrent.Executor;
 
 import javax.annotation.concurrent.Immutable;
 
+import static java.util.concurrent.TimeUnit.MINUTES;
+import static java.util.concurrent.TimeUnit.SECONDS;
 import static org.briarproject.bramble.api.plugin.LanTcpConstants.ID;
 
 @Immutable
 @NotNullByDefault
 public class LanTcpPluginFactory implements DuplexPluginFactory {
 
-	private static final int MAX_LATENCY = 30_000; // 30 seconds
-	private static final int MAX_IDLE_TIME = 30_000; // 30 seconds
-	private static final int CONNECTION_TIMEOUT = 3_000; // 3 seconds
-	private static final int MIN_POLLING_INTERVAL = 60_000; // 1 minute
-	private static final int MAX_POLLING_INTERVAL = 600_000; // 10 mins
-	private static final double BACKOFF_BASE = 1.2;
+	private static final int MAX_LATENCY = (int) SECONDS.toMillis(30);
+	private static final int MAX_IDLE_TIME = (int) SECONDS.toMillis(30);
+	private static final int POLLING_INTERVAL = (int) MINUTES.toMillis(1);
+	private static final int CONNECTION_TIMEOUT = (int) SECONDS.toMillis(3);
 
 	private final Executor ioExecutor;
 	private final EventBus eventBus;
-	private final BackoffFactory backoffFactory;
 
-	public LanTcpPluginFactory(Executor ioExecutor, EventBus eventBus,
-			BackoffFactory backoffFactory) {
+	public LanTcpPluginFactory(Executor ioExecutor, EventBus eventBus) {
 		this.ioExecutor = ioExecutor;
 		this.eventBus = eventBus;
-		this.backoffFactory = backoffFactory;
 	}
 
 	@Override
@@ -49,10 +44,9 @@ public class LanTcpPluginFactory implements DuplexPluginFactory {
 
 	@Override
 	public DuplexPlugin createPlugin(PluginCallback callback) {
-		Backoff backoff = backoffFactory.createBackoff(MIN_POLLING_INTERVAL,
-				MAX_POLLING_INTERVAL, BACKOFF_BASE);
-		LanTcpPlugin plugin =  new LanTcpPlugin(ioExecutor, backoff, callback, MAX_LATENCY,
-				MAX_IDLE_TIME, CONNECTION_TIMEOUT);
+		LanTcpPlugin plugin = new LanTcpPlugin(ioExecutor, callback,
+				MAX_LATENCY, MAX_IDLE_TIME, POLLING_INTERVAL,
+				CONNECTION_TIMEOUT);
 		eventBus.addListener(plugin);
 		return plugin;
 	}

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

@@ -10,7 +10,6 @@ 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.PluginCallback;
 import org.briarproject.bramble.api.plugin.duplex.DuplexPlugin;
@@ -67,9 +66,8 @@ abstract class TcpPlugin implements DuplexPlugin, EventListener {
 			Pattern.compile("^\\d{1,3}\\.\\d{1,3}\\.\\d{1,3}\\.\\d{1,3}$");
 
 	protected final Executor ioExecutor, bindExecutor;
-	protected final Backoff backoff;
 	protected final PluginCallback callback;
-	protected final int maxLatency, maxIdleTime;
+	protected final int maxLatency, maxIdleTime, pollingInterval;
 	protected final int connectionTimeout, socketTimeout;
 	protected final AtomicBoolean used = new AtomicBoolean(false);
 	protected final PluginState state = new PluginState();
@@ -107,13 +105,13 @@ abstract class TcpPlugin implements DuplexPlugin, EventListener {
 	 */
 	protected abstract boolean isEnabledByDefault();
 
-	TcpPlugin(Executor ioExecutor, Backoff backoff, PluginCallback callback,
-			int maxLatency, int maxIdleTime, int connectionTimeout) {
+	TcpPlugin(Executor ioExecutor, PluginCallback callback, int maxLatency,
+			int maxIdleTime, int pollingInterval, int connectionTimeout) {
 		this.ioExecutor = ioExecutor;
-		this.backoff = backoff;
 		this.callback = callback;
 		this.maxLatency = maxLatency;
 		this.maxIdleTime = maxIdleTime;
+		this.pollingInterval = pollingInterval;
 		this.connectionTimeout = connectionTimeout;
 		if (maxIdleTime > Integer.MAX_VALUE / 2)
 			socketTimeout = Integer.MAX_VALUE;
@@ -171,7 +169,6 @@ abstract class TcpPlugin implements DuplexPlugin, EventListener {
 			tryToClose(ss, LOG, WARNING);
 			return;
 		}
-		backoff.reset();
 		InetSocketAddress local =
 				(InetSocketAddress) ss.getLocalSocketAddress();
 		setLocalSocketAddress(local, ipv4);
@@ -204,7 +201,6 @@ abstract class TcpPlugin implements DuplexPlugin, EventListener {
 				LOG.info("Connection from " +
 						scrubSocketAddress(s.getRemoteSocketAddress()));
 			}
-			backoff.reset();
 			callback.handleConnection(new TcpTransportConnection(this, s));
 		}
 	}
@@ -231,14 +227,13 @@ abstract class TcpPlugin implements DuplexPlugin, EventListener {
 
 	@Override
 	public int getPollingInterval() {
-		return backoff.getPollingInterval();
+		return pollingInterval;
 	}
 
 	@Override
 	public void poll(Collection<Pair<TransportProperties, ConnectionHandler>>
 			properties) {
 		if (getState() != ACTIVE) return;
-		backoff.increment();
 		for (Pair<TransportProperties, ConnectionHandler> p : properties) {
 			connect(p.getFirst(), p.getSecond());
 		}
@@ -247,10 +242,7 @@ abstract class TcpPlugin implements DuplexPlugin, EventListener {
 	private void connect(TransportProperties p, ConnectionHandler h) {
 		ioExecutor.execute(() -> {
 			DuplexTransportConnection d = createConnection(p);
-			if (d != null) {
-				backoff.reset();
-				h.handleConnection(d);
-			}
+			if (d != null) h.handleConnection(d);
 		});
 	}
 

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

@@ -2,7 +2,6 @@ package org.briarproject.bramble.plugin.tcp;
 
 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.properties.TransportProperties;
@@ -30,10 +29,10 @@ class WanTcpPlugin extends TcpPlugin {
 
 	private volatile MappingResult mappingResult;
 
-	WanTcpPlugin(Executor ioExecutor, Backoff backoff, PortMapper portMapper,
+	WanTcpPlugin(Executor ioExecutor, PortMapper portMapper,
 			PluginCallback callback, int maxLatency, int maxIdleTime,
-			int connectionTimeout) {
-		super(ioExecutor, backoff, callback, maxLatency, maxIdleTime,
+			int pollingInterval, int connectionTimeout) {
+		super(ioExecutor, callback, maxLatency, maxIdleTime, pollingInterval,
 				connectionTimeout);
 		this.portMapper = portMapper;
 	}

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

@@ -3,8 +3,6 @@ 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;
-import org.briarproject.bramble.api.plugin.BackoffFactory;
 import org.briarproject.bramble.api.plugin.PluginCallback;
 import org.briarproject.bramble.api.plugin.TransportId;
 import org.briarproject.bramble.api.plugin.duplex.DuplexPlugin;
@@ -14,29 +12,27 @@ import java.util.concurrent.Executor;
 
 import javax.annotation.concurrent.Immutable;
 
+import static java.util.concurrent.TimeUnit.MINUTES;
+import static java.util.concurrent.TimeUnit.SECONDS;
 import static org.briarproject.bramble.api.plugin.WanTcpConstants.ID;
 
 @Immutable
 @NotNullByDefault
 public class WanTcpPluginFactory implements DuplexPluginFactory {
 
-	private static final int MAX_LATENCY = 30_000; // 30 seconds
-	private static final int MAX_IDLE_TIME = 30_000; // 30 seconds
-	private static final int CONNECTION_TIMEOUT = 30_000; // 30 seconds
-	private static final int MIN_POLLING_INTERVAL = 60_000; // 1 minute
-	private static final int MAX_POLLING_INTERVAL = 600_000; // 10 mins
-	private static final double BACKOFF_BASE = 1.2;
+	private static final int MAX_LATENCY = (int) SECONDS.toMillis(30);
+	private static final int MAX_IDLE_TIME = (int) SECONDS.toMillis(30);
+	private static final int POLLING_INTERVAL = (int) MINUTES.toMillis(1);
+	private static final int CONNECTION_TIMEOUT = (int) SECONDS.toMillis(30);
 
 	private final Executor ioExecutor;
 	private final EventBus eventBus;
-	private final BackoffFactory backoffFactory;
 	private final ShutdownManager shutdownManager;
 
 	public WanTcpPluginFactory(Executor ioExecutor, EventBus eventBus,
-			BackoffFactory backoffFactory, ShutdownManager shutdownManager) {
+			ShutdownManager shutdownManager) {
 		this.ioExecutor = ioExecutor;
 		this.eventBus = eventBus;
-		this.backoffFactory = backoffFactory;
 		this.shutdownManager = shutdownManager;
 	}
 
@@ -52,11 +48,9 @@ public class WanTcpPluginFactory implements DuplexPluginFactory {
 
 	@Override
 	public DuplexPlugin createPlugin(PluginCallback callback) {
-		Backoff backoff = backoffFactory.createBackoff(MIN_POLLING_INTERVAL,
-				MAX_POLLING_INTERVAL, BACKOFF_BASE);
-		WanTcpPlugin plugin = new WanTcpPlugin(ioExecutor, backoff,
+		WanTcpPlugin plugin = new WanTcpPlugin(ioExecutor,
 				new PortMapperImpl(shutdownManager), callback, MAX_LATENCY,
-				MAX_IDLE_TIME, CONNECTION_TIMEOUT);
+				MAX_IDLE_TIME, POLLING_INTERVAL, CONNECTION_TIMEOUT);
 		eventBus.addListener(plugin);
 		return plugin;
 	}

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

@@ -17,7 +17,6 @@ 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.PluginCallback;
 import org.briarproject.bramble.api.plugin.PluginException;
@@ -46,9 +45,11 @@ import java.net.ServerSocket;
 import java.net.Socket;
 import java.util.ArrayList;
 import java.util.Collection;
+import java.util.HashSet;
 import java.util.List;
 import java.util.Map;
 import java.util.Scanner;
+import java.util.Set;
 import java.util.concurrent.Executor;
 import java.util.concurrent.atomic.AtomicBoolean;
 import java.util.logging.Logger;
@@ -109,28 +110,59 @@ abstract class TorPlugin implements DuplexPlugin, EventHandler, EventListener {
 
 	private static final Logger LOG = getLogger(TorPlugin.class.getName());
 
+	/**
+	 * Controller events we want to receive.
+	 */
 	private static final String[] EVENTS = {
 			"CIRC", "ORCONN", "HS_DESC", "NOTICE", "WARN", "ERR"
 	};
+
+	/**
+	 * Command-line argument to set our process as Tor's owning controller
+	 * so Tor exits when our process dies.
+	 */
 	private static final String OWNER = "__OwningControllerProcess";
+
+	/**
+	 * How long to wait for the authentication cookie file to be created.
+	 */
 	private static final int COOKIE_TIMEOUT_MS = 3000;
+
+	/**
+	 * How often to check whether the authentication cookie file has been
+	 * created.
+	 */
 	private static final int COOKIE_POLLING_INTERVAL_MS = 200;
+
+	/**
+	 * Regex for matching v2 hidden service names.
+	 */
 	private static final Pattern ONION_V2 = Pattern.compile("[a-z2-7]{16}");
+
+	/**
+	 * Regex for matching v3 hidden service names.
+	 */
 	private static final Pattern ONION_V3 = Pattern.compile("[a-z2-7]{56}");
 
+	/**
+	 * How many copies of our descriptor must be uploaded before we consider
+	 * our hidden service to be reachable and switch to less frequent polling.
+	 */
+	private static final int MIN_DESCRIPTORS_UPLOADED = 5;
+
 	private final Executor ioExecutor, connectionStatusExecutor;
 	private final NetworkManager networkManager;
 	private final LocationUtils locationUtils;
 	private final SocketFactory torSocketFactory;
 	private final Clock clock;
 	private final BatteryManager batteryManager;
-	private final Backoff backoff;
 	private final TorRendezvousCrypto torRendezvousCrypto;
 	private final PluginCallback callback;
 	private final String architecture;
 	private final CircumventionProvider circumventionProvider;
 	private final ResourceProvider resourceProvider;
 	private final int maxLatency, maxIdleTime, socketTimeout;
+	private final int initialPollingInterval, stablePollingInterval;
 	private final File torDirectory, torFile, geoIpFile, obfs4File, configFile;
 	private final File doneFile, cookieFile;
 	private final AtomicBoolean used = new AtomicBoolean(false);
@@ -149,10 +181,11 @@ abstract class TorPlugin implements DuplexPlugin, EventHandler, EventListener {
 			LocationUtils locationUtils, SocketFactory torSocketFactory,
 			Clock clock, ResourceProvider resourceProvider,
 			CircumventionProvider circumventionProvider,
-			BatteryManager batteryManager, Backoff backoff,
+			BatteryManager batteryManager,
 			TorRendezvousCrypto torRendezvousCrypto,
 			PluginCallback callback, String architecture, int maxLatency,
-			int maxIdleTime, File torDirectory) {
+			int maxIdleTime, int initialPollingInterval,
+			int stablePollingInterval, File torDirectory) {
 		this.ioExecutor = ioExecutor;
 		this.networkManager = networkManager;
 		this.locationUtils = locationUtils;
@@ -161,7 +194,6 @@ abstract class TorPlugin implements DuplexPlugin, EventHandler, EventListener {
 		this.resourceProvider = resourceProvider;
 		this.circumventionProvider = circumventionProvider;
 		this.batteryManager = batteryManager;
-		this.backoff = backoff;
 		this.torRendezvousCrypto = torRendezvousCrypto;
 		this.callback = callback;
 		this.architecture = architecture;
@@ -170,6 +202,8 @@ abstract class TorPlugin implements DuplexPlugin, EventHandler, EventListener {
 		if (maxIdleTime > Integer.MAX_VALUE / 2)
 			socketTimeout = Integer.MAX_VALUE;
 		else socketTimeout = maxIdleTime * 2;
+		this.initialPollingInterval = initialPollingInterval;
+		this.stablePollingInterval = stablePollingInterval;
 		this.torDirectory = torDirectory;
 		torFile = new File(torDirectory, "tor");
 		geoIpFile = new File(torDirectory, "geoip");
@@ -434,7 +468,6 @@ abstract class TorPlugin implements DuplexPlugin, EventHandler, EventListener {
 			callback.mergeSettings(s);
 			// Create a hidden service if necessary
 			ioExecutor.execute(() -> publishHiddenService(localPort));
-			backoff.reset();
 			// Accept incoming hidden service connections from Tor
 			acceptContactConnections(ss);
 		});
@@ -544,7 +577,6 @@ abstract class TorPlugin implements DuplexPlugin, EventHandler, EventListener {
 				return;
 			}
 			LOG.info("Connection received");
-			backoff.reset();
 			callback.handleConnection(new TorTransportConnection(this, s));
 		}
 	}
@@ -606,14 +638,19 @@ abstract class TorPlugin implements DuplexPlugin, EventHandler, EventListener {
 
 	@Override
 	public int getPollingInterval() {
-		return backoff.getPollingInterval();
+		if (state.isDescriptorPublished()) {
+			LOG.info("Using stable polling interval");
+			return stablePollingInterval;
+		} else {
+			LOG.info("Using initial polling interval");
+			return initialPollingInterval;
+		}
 	}
 
 	@Override
 	public void poll(Collection<Pair<TransportProperties, ConnectionHandler>>
 			properties) {
 		if (getState() != ACTIVE) return;
-		backoff.increment();
 		for (Pair<TransportProperties, ConnectionHandler> p : properties) {
 			connect(p.getFirst(), p.getSecond());
 		}
@@ -622,10 +659,7 @@ abstract class TorPlugin implements DuplexPlugin, EventHandler, EventListener {
 	private void connect(TransportProperties p, ConnectionHandler h) {
 		ioExecutor.execute(() -> {
 			DuplexTransportConnection d = createConnection(p);
-			if (d != null) {
-				backoff.reset();
-				h.handleConnection(d);
-			}
+			if (d != null) h.handleConnection(d);
 		});
 	}
 
@@ -755,10 +789,8 @@ abstract class TorPlugin implements DuplexPlugin, EventHandler, EventListener {
 
 	@Override
 	public void circuitStatus(String status, String id, String path) {
-		if (status.equals("BUILT") &&
-				state.getAndSetCircuitBuilt()) {
+		if (status.equals("BUILT") && state.getAndSetCircuitBuilt()) {
 			LOG.info("First circuit built");
-			backoff.reset();
 		}
 	}
 
@@ -768,8 +800,8 @@ abstract class TorPlugin implements DuplexPlugin, EventHandler, EventListener {
 
 	@Override
 	public void orConnStatus(String status, String orName) {
-		if (LOG.isLoggable(INFO))
-			LOG.info("OR connection " + status + " " + orName);
+		if (LOG.isLoggable(INFO)) LOG.info("OR connection " + status);
+		state.setOrConnectionStatus(orName, status);
 		if (status.equals("CLOSED") || status.equals("FAILED")) {
 			// Check whether we've lost connectivity
 			updateConnectionStatus(networkManager.getNetworkStatus(),
@@ -790,20 +822,18 @@ abstract class TorPlugin implements DuplexPlugin, EventHandler, EventListener {
 		if (LOG.isLoggable(INFO)) LOG.info(severity + " " + msg);
 		if (severity.equals("NOTICE") && msg.startsWith("Bootstrapped 100%")) {
 			state.setBootstrapped();
-			backoff.reset();
 		}
 	}
 
 	@Override
 	public void unrecognized(String type, String msg) {
 		if (type.equals("HS_DESC") && msg.startsWith("UPLOADED")) {
-			if (LOG.isLoggable(INFO)) {
-				String[] words = msg.split(" ");
-				if (words.length > 1 && ONION_V3.matcher(words[1]).matches()) {
-					LOG.info("V3 descriptor uploaded");
-				} else {
-					LOG.info("V2 descriptor uploaded");
-				}
+			String[] words = msg.split(" ");
+			if (words.length > 1 && ONION_V3.matcher(words[1]).matches()) {
+				LOG.info("V3 descriptor uploaded");
+				state.descriptorUploaded();
+			} else {
+				LOG.info("V2 descriptor uploaded");
 			}
 		}
 	}
@@ -959,6 +989,12 @@ abstract class TorPlugin implements DuplexPlugin, EventHandler, EventListener {
 		@Nullable
 		private ServerSocket serverSocket = null;
 
+		@GuardedBy("this")
+		private final Set<String> orConnections = new HashSet<>();
+
+		@GuardedBy("this")
+		private int descriptorsUploaded = 0;
+
 		synchronized void setStarted() {
 			started = true;
 			callback.pluginStateChanged(getState());
@@ -992,7 +1028,10 @@ abstract class TorPlugin implements DuplexPlugin, EventHandler, EventListener {
 		synchronized void enableNetwork(boolean enable) {
 			networkInitialised = true;
 			networkEnabled = enable;
-			if (!enable) circuitBuilt = false;
+			if (!enable) {
+				circuitBuilt = false;
+				descriptorsUploaded = 0;
+			}
 			callback.pluginStateChanged(getState());
 		}
 
@@ -1002,6 +1041,34 @@ abstract class TorPlugin implements DuplexPlugin, EventHandler, EventListener {
 			callback.pluginStateChanged(getState());
 		}
 
+		synchronized void setOrConnectionStatus(String orName, String status) {
+			if (status.equals("CONNECTED")) {
+				if (!orConnections.add(orName)) {
+					LOG.warning("Duplicate OR connection");
+				}
+			} else {
+				orConnections.remove(orName);
+				if (orConnections.isEmpty()) descriptorsUploaded = 0;
+			}
+			if (LOG.isLoggable(INFO)) {
+				LOG.info(orConnections.size() + " OR connections");
+			}
+			callback.pluginStateChanged(getState());
+		}
+
+		// Doesn't affect getState()
+		synchronized void descriptorUploaded() {
+			if (networkEnabled && !orConnections.isEmpty()) {
+				descriptorsUploaded++;
+			} else {
+				LOG.warning("Descriptor was uploaded with no OR connection");
+			}
+		}
+
+		synchronized boolean isDescriptorPublished() {
+			return descriptorsUploaded >= MIN_DESCRIPTORS_UPLOADED;
+		}
+
 		// Doesn't affect getState()
 		synchronized boolean setServerSocket(ServerSocket ss) {
 			if (stopped || serverSocket != null) return false;
@@ -1021,7 +1088,8 @@ abstract class TorPlugin implements DuplexPlugin, EventHandler, EventListener {
 			if (reasonsDisabled != 0) return DISABLED;
 			if (!networkInitialised) return ENABLING;
 			if (!networkEnabled) return INACTIVE;
-			return bootstrapped && circuitBuilt ? ACTIVE : ENABLING;
+			return bootstrapped && circuitBuilt && !orConnections.isEmpty()
+					? ACTIVE : ENABLING;
 		}
 
 		synchronized int getReasonsDisabled() {

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

@@ -1,63 +0,0 @@
-package org.briarproject.bramble.plugin;
-
-import org.briarproject.bramble.test.BrambleTestCase;
-import org.junit.Test;
-
-import static org.junit.Assert.assertEquals;
-import static org.junit.Assert.assertTrue;
-
-public class BackoffImplTest extends BrambleTestCase {
-
-	private static final int MIN_INTERVAL = 60 * 1000;
-	private static final int MAX_INTERVAL = 60 * 60 * 1000;
-	private static final double BASE = 1.2;
-
-	@Test
-	public void testPollingIntervalStartsAtMinimum() {
-		BackoffImpl b = new BackoffImpl(MIN_INTERVAL, MAX_INTERVAL, BASE);
-		assertEquals(MIN_INTERVAL, b.getPollingInterval());
-	}
-
-	@Test
-	public void testIncrementIncreasesPollingInterval() {
-		BackoffImpl b = new BackoffImpl(MIN_INTERVAL, MAX_INTERVAL, BASE);
-		b.increment();
-		assertTrue(b.getPollingInterval() > MIN_INTERVAL);
-	}
-
-	@Test
-	public void testResetResetsPollingInterval() {
-		BackoffImpl b = new BackoffImpl(MIN_INTERVAL, MAX_INTERVAL, BASE);
-		b.increment();
-		b.increment();
-		b.reset();
-		assertEquals(MIN_INTERVAL, b.getPollingInterval());
-	}
-
-	@Test
-	public void testBaseAffectsBackoffSpeed() {
-		BackoffImpl b = new BackoffImpl(MIN_INTERVAL, MAX_INTERVAL, BASE);
-		b.increment();
-		int interval = b.getPollingInterval();
-		BackoffImpl b1 = new BackoffImpl(MIN_INTERVAL, MAX_INTERVAL, BASE * 2);
-		b1.increment();
-		int interval1 = b1.getPollingInterval();
-		assertTrue(interval < interval1);
-	}
-
-	@Test
-	public void testIntervalDoesNotExceedMaxInterval() {
-		BackoffImpl b = new BackoffImpl(MIN_INTERVAL, MAX_INTERVAL, BASE);
-		for (int i = 0; i < 100; i++) b.increment();
-		assertEquals(MAX_INTERVAL, b.getPollingInterval());
-	}
-
-	@Test
-	public void testIntervalDoesNotExceedMaxIntervalWithInfiniteMultiplier() {
-		BackoffImpl b = new BackoffImpl(MIN_INTERVAL, MAX_INTERVAL,
-				Double.POSITIVE_INFINITY);
-		b.increment();
-		assertEquals(MAX_INTERVAL, b.getPollingInterval());
-	}
-}
-

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

@@ -12,7 +12,6 @@ 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.ConnectionClosedEvent;
-import org.briarproject.bramble.api.plugin.event.ConnectionOpenedEvent;
 import org.briarproject.bramble.api.plugin.event.TransportActiveEvent;
 import org.briarproject.bramble.api.plugin.event.TransportInactiveEvent;
 import org.briarproject.bramble.api.plugin.simplex.SimplexPlugin;
@@ -157,22 +156,20 @@ public class PollerImplTest extends BrambleMockTestCase {
 	}
 
 	@Test
-	public void testRescheduleOnOutgoingConnectionClosed() {
+	public void testDoesNotReconnectOnOutgoingConnectionClosed() {
 		DuplexPlugin plugin = context.mock(DuplexPlugin.class);
 
 		context.checking(new Expectations() {{
 			allowing(plugin).getId();
 			will(returnValue(transportId));
 		}});
-		expectReschedule(plugin);
 
 		poller.eventOccurred(new ConnectionClosedEvent(contactId, transportId,
 				false, false));
 	}
 
 	@Test
-	public void testRescheduleAndReconnectOnOutgoingConnectionFailed()
-			throws Exception {
+	public void testReconnectsOnOutgoingConnectionFailed() throws Exception {
 		DuplexPlugin plugin = context.mock(DuplexPlugin.class);
 		DuplexTransportConnection duplexConnection =
 				context.mock(DuplexTransportConnection.class);
@@ -181,7 +178,6 @@ public class PollerImplTest extends BrambleMockTestCase {
 			allowing(plugin).getId();
 			will(returnValue(transportId));
 		}});
-		expectReschedule(plugin);
 		expectReconnect(plugin, duplexConnection);
 
 		poller.eventOccurred(new ConnectionClosedEvent(contactId, transportId,
@@ -189,147 +185,31 @@ public class PollerImplTest extends BrambleMockTestCase {
 	}
 
 	@Test
-	public void testRescheduleOnIncomingConnectionClosed() {
+	public void testDoesNotReconnectOnIncomingConnectionClosed() {
 		DuplexPlugin plugin = context.mock(DuplexPlugin.class);
 
 		context.checking(new Expectations() {{
 			allowing(plugin).getId();
 			will(returnValue(transportId));
 		}});
-		expectReschedule(plugin);
 
 		poller.eventOccurred(new ConnectionClosedEvent(contactId, transportId,
 				true, false));
 	}
 
 	@Test
-	public void testRescheduleOnIncomingConnectionFailed() {
+	public void testDoesNotReconnectOnIncomingConnectionFailed() {
 		DuplexPlugin plugin = context.mock(DuplexPlugin.class);
 
 		context.checking(new Expectations() {{
 			allowing(plugin).getId();
 			will(returnValue(transportId));
 		}});
-		expectReschedule(plugin);
 
 		poller.eventOccurred(new ConnectionClosedEvent(contactId, transportId,
 				true, false));
 	}
 
-	@Test
-	public void testRescheduleOnConnectionOpened() {
-		Plugin plugin = context.mock(Plugin.class);
-
-		context.checking(new Expectations() {{
-			allowing(plugin).getId();
-			will(returnValue(transportId));
-			// Get the plugin
-			oneOf(pluginManager).getPlugin(transportId);
-			will(returnValue(plugin));
-			// The plugin supports polling
-			oneOf(plugin).shouldPoll();
-			will(returnValue(true));
-			// Schedule the next poll
-			oneOf(plugin).getPollingInterval();
-			will(returnValue(pollingInterval));
-			oneOf(clock).currentTimeMillis();
-			will(returnValue(now));
-			oneOf(scheduler).schedule(with(any(Runnable.class)),
-					with((long) pollingInterval), with(MILLISECONDS));
-			will(returnValue(future));
-		}});
-
-		poller.eventOccurred(new ConnectionOpenedEvent(contactId, transportId,
-				false));
-	}
-
-	@Test
-	public void testRescheduleDoesNotReplaceEarlierTask() {
-		Plugin plugin = context.mock(Plugin.class);
-
-		context.checking(new Expectations() {{
-			allowing(plugin).getId();
-			will(returnValue(transportId));
-			// First event
-			// Get the plugin
-			oneOf(pluginManager).getPlugin(transportId);
-			will(returnValue(plugin));
-			// The plugin supports polling
-			oneOf(plugin).shouldPoll();
-			will(returnValue(true));
-			// Schedule the next poll
-			oneOf(plugin).getPollingInterval();
-			will(returnValue(pollingInterval));
-			oneOf(clock).currentTimeMillis();
-			will(returnValue(now));
-			oneOf(scheduler).schedule(with(any(Runnable.class)),
-					with((long) pollingInterval), with(MILLISECONDS));
-			will(returnValue(future));
-			// Second event
-			// Get the plugin
-			oneOf(pluginManager).getPlugin(transportId);
-			will(returnValue(plugin));
-			// The plugin supports polling
-			oneOf(plugin).shouldPoll();
-			will(returnValue(true));
-			// Don't replace the previously scheduled task, due earlier
-			oneOf(plugin).getPollingInterval();
-			will(returnValue(pollingInterval));
-			oneOf(clock).currentTimeMillis();
-			will(returnValue(now + 1));
-		}});
-
-		poller.eventOccurred(new ConnectionOpenedEvent(contactId, transportId,
-				false));
-		poller.eventOccurred(new ConnectionOpenedEvent(contactId, transportId,
-				false));
-	}
-
-	@Test
-	public void testRescheduleReplacesLaterTask() {
-		Plugin plugin = context.mock(Plugin.class);
-
-		context.checking(new Expectations() {{
-			allowing(plugin).getId();
-			will(returnValue(transportId));
-			// First event
-			// Get the plugin
-			oneOf(pluginManager).getPlugin(transportId);
-			will(returnValue(plugin));
-			// The plugin supports polling
-			oneOf(plugin).shouldPoll();
-			will(returnValue(true));
-			// Schedule the next poll
-			oneOf(plugin).getPollingInterval();
-			will(returnValue(pollingInterval));
-			oneOf(clock).currentTimeMillis();
-			will(returnValue(now));
-			oneOf(scheduler).schedule(with(any(Runnable.class)),
-					with((long) pollingInterval), with(MILLISECONDS));
-			will(returnValue(future));
-			// Second event
-			// Get the plugin
-			oneOf(pluginManager).getPlugin(transportId);
-			will(returnValue(plugin));
-			// The plugin supports polling
-			oneOf(plugin).shouldPoll();
-			will(returnValue(true));
-			// Replace the previously scheduled task, due later
-			oneOf(plugin).getPollingInterval();
-			will(returnValue(pollingInterval - 2));
-			oneOf(clock).currentTimeMillis();
-			will(returnValue(now + 1));
-			oneOf(future).cancel(false);
-			oneOf(scheduler).schedule(with(any(Runnable.class)),
-					with((long) pollingInterval - 2), with(MILLISECONDS));
-		}});
-
-		poller.eventOccurred(new ConnectionOpenedEvent(contactId, transportId,
-				false));
-		poller.eventOccurred(new ConnectionOpenedEvent(contactId, transportId,
-				false));
-	}
-
 	@Test
 	public void testPollsOnTransportActivated() throws Exception {
 		DuplexPlugin plugin = context.mock(DuplexPlugin.class);
@@ -441,25 +321,6 @@ public class PollerImplTest extends BrambleMockTestCase {
 		poller.eventOccurred(new TransportInactiveEvent(transportId));
 	}
 
-	private void expectReschedule(Plugin plugin) {
-		context.checking(new Expectations() {{
-			// Get the plugin
-			oneOf(pluginManager).getPlugin(transportId);
-			will(returnValue(plugin));
-			// The plugin supports polling
-			oneOf(plugin).shouldPoll();
-			will(returnValue(true));
-			// Schedule the next poll
-			oneOf(plugin).getPollingInterval();
-			will(returnValue(pollingInterval));
-			oneOf(clock).currentTimeMillis();
-			will(returnValue(now));
-			oneOf(scheduler).schedule(with(any(Runnable.class)),
-					with((long) pollingInterval), with(MILLISECONDS));
-			will(returnValue(future));
-		}});
-	}
-
 	private void expectReconnect(DuplexPlugin plugin,
 			DuplexTransportConnection duplexConnection) throws Exception {
 		context.checking(new Expectations() {{

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

@@ -3,7 +3,6 @@ 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.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;
@@ -42,7 +41,6 @@ import static org.junit.Assume.assumeTrue;
 
 public class LanTcpPluginTest extends BrambleTestCase {
 
-	private final Backoff backoff = new TestBackoff();
 	private final ExecutorService ioExecutor = newCachedThreadPool();
 
 	private Callback callback = null;
@@ -51,7 +49,7 @@ public class LanTcpPluginTest extends BrambleTestCase {
 	@Before
 	public void setUp() {
 		callback = new Callback();
-		plugin = new LanTcpPlugin(ioExecutor, backoff, callback, 0, 0, 1000) {
+		plugin = new LanTcpPlugin(ioExecutor, callback, 0, 0, 0, 1000) {
 			@Override
 			protected boolean canConnectToOwnAddress() {
 				return true;
@@ -347,20 +345,4 @@ public class LanTcpPluginTest extends BrambleTestCase {
 		public void handleWriter(TransportConnectionWriter w) {
 		}
 	}
-
-	private static class TestBackoff implements Backoff {
-
-		@Override
-		public int getPollingInterval() {
-			return 60 * 1000;
-		}
-
-		@Override
-		public void increment() {
-		}
-
-		@Override
-		public void reset() {
-		}
-	}
 }

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

@@ -5,7 +5,6 @@ import org.briarproject.bramble.api.io.TimeoutMonitor;
 import org.briarproject.bramble.api.lifecycle.IoExecutor;
 import org.briarproject.bramble.api.lifecycle.ShutdownManager;
 import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
-import org.briarproject.bramble.api.plugin.BackoffFactory;
 import org.briarproject.bramble.api.plugin.BluetoothConstants;
 import org.briarproject.bramble.api.plugin.LanTcpConstants;
 import org.briarproject.bramble.api.plugin.PluginConfig;
@@ -37,18 +36,16 @@ public class DesktopPluginModule extends PluginModule {
 
 	@Provides
 	PluginConfig getPluginConfig(@IoExecutor Executor ioExecutor,
-			SecureRandom random, BackoffFactory backoffFactory,
-			ReliabilityLayerFactory reliabilityFactory,
+			SecureRandom random, ReliabilityLayerFactory reliabilityFactory,
 			ShutdownManager shutdownManager, EventBus eventBus,
 			TimeoutMonitor timeoutMonitor) {
 		DuplexPluginFactory bluetooth = new JavaBluetoothPluginFactory(
-				ioExecutor, random, eventBus, timeoutMonitor, backoffFactory);
+				ioExecutor, random, eventBus, timeoutMonitor);
 		DuplexPluginFactory modem = new ModemPluginFactory(ioExecutor,
 				reliabilityFactory);
-		DuplexPluginFactory lan = new LanTcpPluginFactory(ioExecutor, eventBus,
-				backoffFactory);
+		DuplexPluginFactory lan = new LanTcpPluginFactory(ioExecutor, eventBus);
 		DuplexPluginFactory wan = new WanTcpPluginFactory(ioExecutor, eventBus,
-				backoffFactory, shutdownManager);
+				shutdownManager);
 		Collection<DuplexPluginFactory> duplex =
 				asList(bluetooth, modem, lan, wan);
 		@NotNullByDefault

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

@@ -3,7 +3,6 @@ package org.briarproject.bramble.plugin.bluetooth;
 import org.briarproject.bramble.api.io.TimeoutMonitor;
 import org.briarproject.bramble.api.nullsafety.MethodsNotNullByDefault;
 import org.briarproject.bramble.api.nullsafety.ParametersNotNullByDefault;
-import org.briarproject.bramble.api.plugin.Backoff;
 import org.briarproject.bramble.api.plugin.PluginCallback;
 import org.briarproject.bramble.api.plugin.duplex.DuplexTransportConnection;
 
@@ -36,10 +35,10 @@ class JavaBluetoothPlugin extends BluetoothPlugin<StreamConnectionNotifier> {
 
 	JavaBluetoothPlugin(BluetoothConnectionLimiter connectionManager,
 			TimeoutMonitor timeoutMonitor, Executor ioExecutor,
-			SecureRandom secureRandom, Backoff backoff,
-			PluginCallback callback, int maxLatency, int maxIdleTime) {
+			SecureRandom secureRandom, PluginCallback callback, int maxLatency,
+			int maxIdleTime, int pollingInterval) {
 		super(connectionManager, timeoutMonitor, ioExecutor, secureRandom,
-				backoff, callback, maxLatency, maxIdleTime);
+				callback, maxLatency, maxIdleTime, pollingInterval);
 	}
 
 	@Override

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

@@ -3,8 +3,6 @@ package org.briarproject.bramble.plugin.bluetooth;
 import org.briarproject.bramble.api.event.EventBus;
 import org.briarproject.bramble.api.io.TimeoutMonitor;
 import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
-import org.briarproject.bramble.api.plugin.Backoff;
-import org.briarproject.bramble.api.plugin.BackoffFactory;
 import org.briarproject.bramble.api.plugin.PluginCallback;
 import org.briarproject.bramble.api.plugin.TransportId;
 import org.briarproject.bramble.api.plugin.duplex.DuplexPlugin;
@@ -15,32 +13,30 @@ import java.util.concurrent.Executor;
 
 import javax.annotation.concurrent.Immutable;
 
+import static java.util.concurrent.TimeUnit.MINUTES;
+import static java.util.concurrent.TimeUnit.SECONDS;
 import static org.briarproject.bramble.api.plugin.BluetoothConstants.ID;
 
 @Immutable
 @NotNullByDefault
 public class JavaBluetoothPluginFactory implements DuplexPluginFactory {
 
-	private static final int MAX_LATENCY = 30 * 1000; // 30 seconds
-	private static final int MAX_IDLE_TIME = 30 * 1000; // 30 seconds
-	private static final int MIN_POLLING_INTERVAL = 60 * 1000; // 1 minute
-	private static final int MAX_POLLING_INTERVAL = 10 * 60 * 1000; // 10 mins
-	private static final double BACKOFF_BASE = 1.2;
+	private static final int MAX_LATENCY = (int) SECONDS.toMillis(30);
+	private static final int MAX_IDLE_TIME = (int) SECONDS.toMillis(30);
+	private static final int POLLING_INTERVAL = (int) MINUTES.toMillis(2);
 
 	private final Executor ioExecutor;
 	private final SecureRandom secureRandom;
 	private final EventBus eventBus;
 	private final TimeoutMonitor timeoutMonitor;
-	private final BackoffFactory backoffFactory;
 
 	public JavaBluetoothPluginFactory(Executor ioExecutor,
 			SecureRandom secureRandom, EventBus eventBus,
-			TimeoutMonitor timeoutMonitor, BackoffFactory backoffFactory) {
+			TimeoutMonitor timeoutMonitor) {
 		this.ioExecutor = ioExecutor;
 		this.secureRandom = secureRandom;
 		this.eventBus = eventBus;
 		this.timeoutMonitor = timeoutMonitor;
-		this.backoffFactory = backoffFactory;
 	}
 
 	@Override
@@ -57,11 +53,9 @@ public class JavaBluetoothPluginFactory implements DuplexPluginFactory {
 	public DuplexPlugin createPlugin(PluginCallback callback) {
 		BluetoothConnectionLimiter connectionLimiter =
 				new BluetoothConnectionLimiterImpl(eventBus);
-		Backoff backoff = backoffFactory.createBackoff(MIN_POLLING_INTERVAL,
-				MAX_POLLING_INTERVAL, BACKOFF_BASE);
 		JavaBluetoothPlugin plugin = new JavaBluetoothPlugin(connectionLimiter,
-				timeoutMonitor, ioExecutor, secureRandom, backoff, callback,
-				MAX_LATENCY, MAX_IDLE_TIME);
+				timeoutMonitor, ioExecutor, secureRandom, callback, MAX_LATENCY,
+				MAX_IDLE_TIME, POLLING_INTERVAL);
 		eventBus.addListener(plugin);
 		return plugin;
 	}

bramble-java/src/main/java/org/briarproject/bramble/plugin/tor/JavaTorPlugin.java

@@ -3,7 +3,6 @@ package org.briarproject.bramble.plugin.tor;
 import org.briarproject.bramble.api.battery.BatteryManager;
 import org.briarproject.bramble.api.network.NetworkManager;
 import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
-import org.briarproject.bramble.api.plugin.Backoff;
 import org.briarproject.bramble.api.plugin.PluginCallback;
 import org.briarproject.bramble.api.system.Clock;
 import org.briarproject.bramble.api.system.LocationUtils;
@@ -24,14 +23,16 @@ abstract class JavaTorPlugin extends TorPlugin {
 			LocationUtils locationUtils, SocketFactory torSocketFactory,
 			Clock clock, ResourceProvider resourceProvider,
 			CircumventionProvider circumventionProvider,
-			BatteryManager batteryManager, Backoff backoff,
+			BatteryManager batteryManager,
 			TorRendezvousCrypto torRendezvousCrypto,
 			PluginCallback callback, String architecture, int maxLatency,
-			int maxIdleTime, File torDirectory) {
+			int maxIdleTime, int initialPollingInterval,
+			int stablePollingInterval, File torDirectory) {
 		super(ioExecutor, networkManager, locationUtils, torSocketFactory,
 				clock, resourceProvider, circumventionProvider, batteryManager,
-				backoff, torRendezvousCrypto, callback, architecture,
-				maxLatency, maxIdleTime, torDirectory);
+				torRendezvousCrypto, callback, architecture, maxLatency,
+				maxIdleTime, initialPollingInterval, stablePollingInterval,
+				torDirectory);
 	}
 
 	@Override

bramble-java/src/main/java/org/briarproject/bramble/plugin/tor/UnixTorPlugin.java

@@ -6,7 +6,6 @@ import com.sun.jna.Native;
 import org.briarproject.bramble.api.battery.BatteryManager;
 import org.briarproject.bramble.api.network.NetworkManager;
 import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
-import org.briarproject.bramble.api.plugin.Backoff;
 import org.briarproject.bramble.api.plugin.PluginCallback;
 import org.briarproject.bramble.api.system.Clock;
 import org.briarproject.bramble.api.system.LocationUtils;
@@ -24,14 +23,16 @@ class UnixTorPlugin extends JavaTorPlugin {
 			LocationUtils locationUtils, SocketFactory torSocketFactory,
 			Clock clock, ResourceProvider resourceProvider,
 			CircumventionProvider circumventionProvider,
-			BatteryManager batteryManager, Backoff backoff,
+			BatteryManager batteryManager,
 			TorRendezvousCrypto torRendezvousCrypto,
 			PluginCallback callback, String architecture, int maxLatency,
-			int maxIdleTime, File torDirectory) {
+			int maxIdleTime, int initialPollingInterval,
+			int stablePollingInterval, File torDirectory) {
 		super(ioExecutor, networkManager, locationUtils, torSocketFactory,
 				clock, resourceProvider, circumventionProvider, batteryManager,
-				backoff, torRendezvousCrypto, callback, architecture,
-				maxLatency, maxIdleTime, torDirectory);
+				torRendezvousCrypto, callback, architecture,
+				maxLatency, maxIdleTime, initialPollingInterval,
+				stablePollingInterval, torDirectory);
 	}
 
 	@Override

bramble-java/src/main/java/org/briarproject/bramble/plugin/tor/UnixTorPluginFactory.java

@@ -4,8 +4,6 @@ import org.briarproject.bramble.api.battery.BatteryManager;
 import org.briarproject.bramble.api.event.EventBus;
 import org.briarproject.bramble.api.network.NetworkManager;
 import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
-import org.briarproject.bramble.api.plugin.Backoff;
-import org.briarproject.bramble.api.plugin.BackoffFactory;
 import org.briarproject.bramble.api.plugin.PluginCallback;
 import org.briarproject.bramble.api.plugin.TorConstants;
 import org.briarproject.bramble.api.plugin.TransportId;
@@ -22,6 +20,8 @@ import java.util.logging.Logger;
 import javax.annotation.concurrent.Immutable;
 import javax.net.SocketFactory;
 
+import static java.util.concurrent.TimeUnit.MINUTES;
+import static java.util.concurrent.TimeUnit.SECONDS;
 import static java.util.logging.Logger.getLogger;
 import static org.briarproject.bramble.util.OsUtils.isLinux;
 
@@ -32,18 +32,28 @@ public class UnixTorPluginFactory implements DuplexPluginFactory {
 	private static final Logger LOG =
 			getLogger(UnixTorPluginFactory.class.getName());
 
-	private static final int MAX_LATENCY = 30 * 1000; // 30 seconds
-	private static final int MAX_IDLE_TIME = 30 * 1000; // 30 seconds
-	private static final int MIN_POLLING_INTERVAL = 60 * 1000; // 1 minute
-	private static final int MAX_POLLING_INTERVAL = 10 * 60 * 1000; // 10 mins
-	private static final double BACKOFF_BASE = 1.2;
+	private static final int MAX_LATENCY = (int) SECONDS.toMillis(30);
+	private static final int MAX_IDLE_TIME = (int) SECONDS.toMillis(30);
+
+	/**
+	 * How often to poll before our hidden service becomes reachable.
+	 */
+	private static final int INITIAL_POLLING_INTERVAL =
+			(int) MINUTES.toMillis(1);
+
+	/**
+	 * How often to poll when our hidden service is reachable. Our contacts
+	 * will poll when they come online, so our polling is just a fallback in
+	 * case of repeated connection failures.
+	 */
+	private static final int STABLE_POLLING_INTERVAL =
+			(int) MINUTES.toMillis(15);
 
 	private final Executor ioExecutor;
 	private final NetworkManager networkManager;
 	private final LocationUtils locationUtils;
 	private final EventBus eventBus;
 	private final SocketFactory torSocketFactory;
-	private final BackoffFactory backoffFactory;
 	private final ResourceProvider resourceProvider;
 	private final CircumventionProvider circumventionProvider;
 	private final BatteryManager batteryManager;
@@ -53,7 +63,7 @@ public class UnixTorPluginFactory implements DuplexPluginFactory {
 	public UnixTorPluginFactory(Executor ioExecutor,
 			NetworkManager networkManager, LocationUtils locationUtils,
 			EventBus eventBus, SocketFactory torSocketFactory,
-			BackoffFactory backoffFactory, ResourceProvider resourceProvider,
+			ResourceProvider resourceProvider,
 			CircumventionProvider circumventionProvider,
 			BatteryManager batteryManager, Clock clock, File torDirectory) {
 		this.ioExecutor = ioExecutor;
@@ -61,7 +71,6 @@ public class UnixTorPluginFactory implements DuplexPluginFactory {
 		this.locationUtils = locationUtils;
 		this.eventBus = eventBus;
 		this.torSocketFactory = torSocketFactory;
-		this.backoffFactory = backoffFactory;
 		this.resourceProvider = resourceProvider;
 		this.circumventionProvider = circumventionProvider;
 		this.batteryManager = batteryManager;
@@ -94,14 +103,13 @@ public class UnixTorPluginFactory implements DuplexPluginFactory {
 			return null;
 		}
 
-		Backoff backoff = backoffFactory.createBackoff(MIN_POLLING_INTERVAL,
-				MAX_POLLING_INTERVAL, BACKOFF_BASE);
 		TorRendezvousCrypto torRendezvousCrypto = new TorRendezvousCryptoImpl();
 		UnixTorPlugin plugin = new UnixTorPlugin(ioExecutor, networkManager,
 				locationUtils, torSocketFactory, clock, resourceProvider,
-				circumventionProvider, batteryManager, backoff,
-				torRendezvousCrypto, callback, architecture, MAX_LATENCY,
-				MAX_IDLE_TIME, torDirectory);
+				circumventionProvider, batteryManager, torRendezvousCrypto,
+				callback, architecture, MAX_LATENCY, MAX_IDLE_TIME,
+				INITIAL_POLLING_INTERVAL, STABLE_POLLING_INTERVAL,
+				torDirectory);
 		eventBus.addListener(plugin);
 		return plugin;
 	}

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

@@ -5,7 +5,6 @@ import org.briarproject.bramble.api.battery.BatteryManager;
 import org.briarproject.bramble.api.event.EventBus;
 import org.briarproject.bramble.api.lifecycle.IoExecutor;
 import org.briarproject.bramble.api.network.NetworkManager;
-import org.briarproject.bramble.api.plugin.BackoffFactory;
 import org.briarproject.bramble.api.plugin.duplex.DuplexPlugin;
 import org.briarproject.bramble.api.system.Clock;
 import org.briarproject.bramble.api.system.LocationUtils;
@@ -69,8 +68,6 @@ public class BridgeTest extends BrambleTestCase {
 	@Inject
 	EventBus eventBus;
 	@Inject
-	BackoffFactory backoffFactory;
-	@Inject
 	Clock clock;
 
 	private final File torDir = getTestDirectory();
@@ -120,9 +117,8 @@ public class BridgeTest extends BrambleTestCase {
 			}
 		};
 		factory = new UnixTorPluginFactory(ioExecutor, networkManager,
-				locationUtils, eventBus, torSocketFactory, backoffFactory,
-				resourceProvider, bridgeProvider, batteryManager, clock,
-				torDir);
+				locationUtils, eventBus, torSocketFactory, resourceProvider,
+				bridgeProvider, batteryManager, clock, torDir);
 	}
 
 	@After

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

@@ -19,7 +19,6 @@ import org.briarproject.bramble.api.lifecycle.IoExecutor;
 import org.briarproject.bramble.api.lifecycle.LifecycleManager;
 import org.briarproject.bramble.api.network.NetworkManager;
 import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
-import org.briarproject.bramble.api.plugin.BackoffFactory;
 import org.briarproject.bramble.api.plugin.BluetoothConstants;
 import org.briarproject.bramble.api.plugin.LanTcpConstants;
 import org.briarproject.bramble.api.plugin.PluginConfig;
@@ -127,23 +126,22 @@ public class AppModule {
 	PluginConfig providePluginConfig(@IoExecutor Executor ioExecutor,
 			@Scheduler ScheduledExecutorService scheduler,
 			AndroidExecutor androidExecutor, SecureRandom random,
-			SocketFactory torSocketFactory, BackoffFactory backoffFactory,
-			Application app, NetworkManager networkManager,
-			LocationUtils locationUtils, EventBus eventBus,
-			ResourceProvider resourceProvider,
+			SocketFactory torSocketFactory, Application app,
+			NetworkManager networkManager, LocationUtils locationUtils,
+			EventBus eventBus, ResourceProvider resourceProvider,
 			CircumventionProvider circumventionProvider,
 			BatteryManager batteryManager, Clock clock,
 			TimeoutMonitor timeoutMonitor) {
 		Context appContext = app.getApplicationContext();
 		DuplexPluginFactory bluetooth = new AndroidBluetoothPluginFactory(
 				ioExecutor, scheduler, androidExecutor, appContext, random,
-				eventBus, clock, timeoutMonitor, backoffFactory);
+				eventBus, clock, timeoutMonitor);
 		DuplexPluginFactory tor = new AndroidTorPluginFactory(ioExecutor,
 				scheduler, appContext, networkManager, locationUtils, eventBus,
-				torSocketFactory, backoffFactory, resourceProvider,
-				circumventionProvider, batteryManager, clock);
+				torSocketFactory, resourceProvider, circumventionProvider,
+				batteryManager, clock);
 		DuplexPluginFactory lan = new AndroidLanTcpPluginFactory(ioExecutor,
-				eventBus, backoffFactory, appContext);
+				eventBus, appContext);
 		Collection<DuplexPluginFactory> duplex = asList(bluetooth, tor, lan);
 		@NotNullByDefault
 		PluginConfig pluginConfig = new PluginConfig() {

briar-headless/src/main/java/org/briarproject/briar/headless/HeadlessModule.kt

@@ -9,7 +9,6 @@ import org.briarproject.bramble.api.db.DatabaseConfig
 import org.briarproject.bramble.api.event.EventBus
 import org.briarproject.bramble.api.lifecycle.IoExecutor
 import org.briarproject.bramble.api.network.NetworkManager
-import org.briarproject.bramble.api.plugin.BackoffFactory
 import org.briarproject.bramble.api.plugin.PluginConfig
 import org.briarproject.bramble.api.plugin.TransportId
 import org.briarproject.bramble.api.plugin.duplex.DuplexPluginFactory
@@ -70,16 +69,15 @@ internal class HeadlessModule(private val appDir: File) {
     @Provides
     internal fun providePluginConfig(
         @IoExecutor ioExecutor: Executor, torSocketFactory: SocketFactory,
-        backoffFactory: BackoffFactory, networkManager: NetworkManager,
-        locationUtils: LocationUtils, eventBus: EventBus, resourceProvider: ResourceProvider,
-        circumventionProvider: CircumventionProvider, batteryManager: BatteryManager, clock: Clock
+        networkManager: NetworkManager, locationUtils: LocationUtils, eventBus: EventBus,
+        resourceProvider: ResourceProvider, circumventionProvider: CircumventionProvider,
+        batteryManager: BatteryManager, clock: Clock
     ): PluginConfig {
         val duplex: List<DuplexPluginFactory> = if (isLinux() || isMac()) {
             val torDirectory = File(appDir, "tor")
             val tor = UnixTorPluginFactory(
                 ioExecutor, networkManager, locationUtils, eventBus, torSocketFactory,
-                backoffFactory, resourceProvider, circumventionProvider, batteryManager, clock,
-                torDirectory
+                resourceProvider, circumventionProvider, batteryManager, clock, torDirectory
             )
             listOf(tor)
         } else {