don't start tor if it's probably blocked

briar-android/src/org/briarproject/plugins/AndroidPluginsModule.java

@@ -13,6 +13,7 @@ import org.briarproject.api.plugins.duplex.DuplexPluginConfig;
 import org.briarproject.api.plugins.duplex.DuplexPluginFactory;
 import org.briarproject.api.plugins.simplex.SimplexPluginConfig;
 import org.briarproject.api.plugins.simplex.SimplexPluginFactory;
+import org.briarproject.api.system.LocationUtils;
 import org.briarproject.plugins.droidtooth.DroidtoothPluginFactory;
 import org.briarproject.plugins.tcp.LanTcpPluginFactory;
 import org.briarproject.plugins.tor.TorPluginFactory;
@@ -39,12 +40,13 @@ public class AndroidPluginsModule extends AbstractModule {
 	DuplexPluginConfig getDuplexPluginConfig(
 			@PluginExecutor Executor pluginExecutor,
 			AndroidExecutor androidExecutor, Context appContext,
-			CryptoComponent crypto, ShutdownManager shutdownManager) {
+			CryptoComponent crypto, LocationUtils locationUtils,
+			ShutdownManager shutdownManager) {
 		DuplexPluginFactory droidtooth = new DroidtoothPluginFactory(
 				pluginExecutor, androidExecutor, appContext,
 				crypto.getSecureRandom());
 		DuplexPluginFactory tor = new TorPluginFactory(pluginExecutor,
-				appContext, shutdownManager);
+				appContext, locationUtils, shutdownManager);
 		DuplexPluginFactory lan = new LanTcpPluginFactory(pluginExecutor);
 		final Collection<DuplexPluginFactory> factories =
 				Arrays.asList(droidtooth, tor, lan);

briar-android/src/org/briarproject/plugins/tor/TorNetworkMetadata.java

@@ -0,0 +1,39 @@
+package org.briarproject.plugins.tor;
+
+import java.util.Arrays;
+import java.util.HashSet;
+import java.util.Set;
+import java.util.logging.Logger;
+
+import org.briarproject.api.system.LocationUtils;
+
+public class TorNetworkMetadata {
+
+	private static final Logger LOG =
+			Logger.getLogger(TorNetworkMetadata.class.getName());
+
+	// for country codes see https://en.wikipedia.org/wiki/ISO_3166-1_alpha-2
+	// below list from https://trac.torproject.org/projects/tor/wiki/doc/OONI/censorshipwiki
+	// TODO: get a more complete list
+	public static final Set<String> BLOCKED_IN_COUNTRIES = new HashSet<String>(Arrays.asList(
+		"CN",
+		"IR",
+		"SY",
+		//"ET", // possibly lifted       - https://metrics.torproject.org/users.html?graph=userstats-relay-country&start=2012-02-08&end=2014-02-06&country=et&events=off#userstats-relay-country
+		//"KZ", // unclear due to botnet - https://metrics.torproject.org/users.html?graph=userstats-relay-country&start=2012-02-08&end=2014-02-06&country=kz&events=off#userstats-relay-country
+		//"PH", // unclear due to botnet - https://metrics.torproject.org/users.html?graph=userstats-relay-country&start=2012-02-08&end=2014-02-06&country=ph&events=off#userstats-relay-country
+		//"AE", // unclear due to botnet - https://metrics.torproject.org/users.html?graph=userstats-relay-country&start=2012-02-08&end=2014-02-06&country=ae&events=off#userstats-relay-country
+		//"GB", // for testing
+		"ZZ"
+	));
+
+	public static boolean isTorProbablyBlocked(LocationUtils locationUtils) {
+		String countryCode = locationUtils.getCurrentCountry();
+		if (BLOCKED_IN_COUNTRIES.contains(countryCode)) {
+			LOG.info("Tor is probably blocked in your country: " + countryCode);
+			return true;
+		}
+		return false;
+	}
+
+}

briar-android/src/org/briarproject/plugins/tor/TorPluginFactory.java

@@ -1,30 +1,39 @@
 package org.briarproject.plugins.tor;
 
 import java.util.concurrent.Executor;
+import java.util.logging.Logger;
 
 import org.briarproject.api.TransportId;
 import org.briarproject.api.lifecycle.ShutdownManager;
 import org.briarproject.api.plugins.duplex.DuplexPlugin;
 import org.briarproject.api.plugins.duplex.DuplexPluginCallback;
 import org.briarproject.api.plugins.duplex.DuplexPluginFactory;
+import org.briarproject.api.system.LocationUtils;
+import org.briarproject.plugins.AndroidPluginsModule;
+import org.briarproject.plugins.tor.TorNetworkMetadata;
 
 import android.content.Context;
 import android.os.Build;
 
 public class TorPluginFactory implements DuplexPluginFactory {
 
+	private static final Logger LOG =
+			Logger.getLogger(TorPluginFactory.class.getName());
+
 	private static final int MAX_FRAME_LENGTH = 1024;
 	private static final long MAX_LATENCY = 60 * 1000; // 1 minute
 	private static final long POLLING_INTERVAL = 3 * 60 * 1000; // 3 minutes
 
 	private final Executor pluginExecutor;
 	private final Context appContext;
+	private final LocationUtils locationUtils;
 	private final ShutdownManager shutdownManager;
 
 	public TorPluginFactory(Executor pluginExecutor, Context appContext,
-			ShutdownManager shutdownManager) {
+			LocationUtils locationUtils, ShutdownManager shutdownManager) {
 		this.pluginExecutor = pluginExecutor;
 		this.appContext = appContext;
+		this.locationUtils = locationUtils;
 		this.shutdownManager = shutdownManager;
 	}
 
@@ -35,6 +44,11 @@ public class TorPluginFactory implements DuplexPluginFactory {
 	public DuplexPlugin createPlugin(DuplexPluginCallback callback) {
 		// Check that we have a Tor binary for this architecture
 		if(!Build.CPU_ABI.startsWith("armeabi")) return null;
+		// Check that we don't know that Tor is blocked here
+		if (TorNetworkMetadata.isTorProbablyBlocked(locationUtils)) {
+			LOG.info("Tor has been pre-emptively disabled since it is probably blocked");
+			return null;
+		}
 		return new TorPlugin(pluginExecutor,appContext, shutdownManager,
 				callback, MAX_FRAME_LENGTH, MAX_LATENCY, POLLING_INTERVAL);
 	}