CONTRIBUTING.md

+Folder-Description:
+===================
+* `briar-*`: Specifically for the Briar app (Phone/Desktop/Headless)
+* `bramble-*`: The protocol stack - not necessarily Briar-dependent
+
+---
+
+* `*-api`: public stuff that can be referenced from other packages and modules - mostly interfaces + a few utility classes
+* `*-core`: implementations of api that are portable across Android/Desktop/Headless
+* `*-java`: implementations of api that are specific to Desktop & Headless

LICENSE.txt

@@ -13,23 +13,6 @@
     You should have received a copy of the GNU General Public License
     along with this program.  If not, see <http://www.gnu.org/licenses/>.
 
--------------------------------------------------------------------------
-
-    All files under the directories briar-android/src, briar-api/src,
-    briar-core/src, briar-desktop/src and briar-test/src are licensed
-    under the Apache License, version 2.0 (the "License"); you may not
-    use these files except in compliance with the License.
-
-    You may obtain a copy of the License at
-
-    http://www.apache.org/licenses/LICENSE-2.0
-
-    Unless required by applicable law or agreed to in writing, software
-    distributed under the License is distributed on an "AS IS" BASIS,
-    WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or
-    implied. See the License for the specific language governing
-    permissions and limitations under the License.
-
 -------------------------------------------------------------------------
 
                     GNU GENERAL PUBLIC LICENSE

README.md

-Briar is a messaging app designed for activists, journalists, and anyone else who needs a safe, easy and robust way to communicate. Unlike traditional messaging tools such as email, Twitter or Telegram, Briar doesn't rely on a central server - messages are synchronized directly between the users' devices. If the Internet's down, Briar can sync via Bluetooth or Wi-Fi, keeping the information flowing in a crisis. If the Internet's up, Briar can sync via the Tor network, protecting users and their relationships from surveillance.
+# Briar
+Briar is a messaging app designed for activists, journalists, and anyone else who needs a safe, easy and robust way to communicate.
+
+Unlike traditional messaging apps, Briar doesn't rely on a central server - messages are synchronized directly between the users' devices. 
+
+If the Internet's down, Briar can sync via Bluetooth or Wi-Fi, keeping information flowing in a crisis. If the Internet's up, Briar can sync via the Tor network, protecting users and their relationships from surveillance.
+
+## Download Briar
+
+[<img src="https://briarproject.org//img/fdroid_badge.png"  width="240">](https://briarproject.org/fdroid)
+[<img src="https://briarproject.org/img/google_play_badge_web_generic.png"  width="240">](https://play.google.com/store/apps/details?id=org.briarproject.briar.android)
+
+You can also [download the APK file](https://briarproject.org/apk) directly from
+our site.
+
+## Useful links
+[Project website](https://briarproject.org/)
+
+[Source code](https://code.briarproject.org/briar/briar/tree/master)
+
+[User manual](https://briarproject.org/manual/)
+
+[Wiki](https://code.briarproject.org/briar/briar/-/wikis/home)
+
+[Privacy policy](https://briarproject.org/privacy)
+
+## Reproducible builds
+
+We provide [docker images](https://code.briarproject.org/briar/briar-reproducer#briar-reproducer)
+to ease the task of verifying that the published APK binaries
+include nothing but our publicly available source code.
+
+You can either use those images or use them as a blueprint to build your own environment
+for reproduction.
+
+## Donate
+
+[![Donate using Liberapay](https://briarproject.org/img/liberapay.svg)](https://liberapay.com/Briar/donate)   
+Bitcoin and BCH: 1NZCKkUCtJV2U2Y9hDb9uq8S7ksFCFGR6K

TRANSLATION.md

+Translations for this project are managed through Transifex:
+
+https://transifex.com/otf/briar
+
+If you'd like to volunteer as a translator, please create a Transifex account and request to be
+added to the project's translation team. The Localization Lab has some instructions and advice for
+translators here:
+
+https://wiki.localizationlab.org/index.php/Briar

bramble-android/.gitignore

+bin
+gen
+build
+.settings
+src/main/res/raw/*.zip
+src/main/jniLibs
\ No newline at end of file

bramble-android/build.gradle

+apply plugin: 'com.android.library'
+apply plugin: 'witness'
+apply from: 'witness.gradle'
+
+android {
+	compileSdkVersion 34
+	buildToolsVersion '34.0.0'
+
+	packagingOptions {
+		doNotStrip '**/*.so'
+	}
+
+	defaultConfig {
+		minSdkVersion 21
+		targetSdkVersion 33
+		versionCode 10514
+		versionName "1.5.14"
+		consumerProguardFiles 'proguard-rules.txt'
+
+		testInstrumentationRunner "androidx.test.runner.AndroidJUnitRunner"
+		testInstrumentationRunnerArguments disableAnalytics: 'true'
+	}
+
+	compileOptions {
+		sourceCompatibility JavaVersion.VERSION_1_8
+		targetCompatibility JavaVersion.VERSION_1_8
+	}
+
+	lintOptions {
+		// FIXME
+		warning "LintError"
+		warning "InvalidPackage"
+		warning "MissingPermission"
+		warning "InlinedApi", "ObsoleteSdkInt", "Override", "NewApi", "UnusedAttribute"
+	}
+}
+
+configurations {
+	tor
+}
+
+dependencies {
+	api 'org.briarproject:dont-kill-me-lib:0.2.8'
+
+	// In theory this dependency shouldn't be needed, but without it Android Studio's linter will
+	// complain about unresolved symbols for bramble-api test classes in bramble-android tests,
+	// even though the bramble-api test classes are provided by the testImplementation dependency
+	// below and the compiler can find them
+	implementation project(':bramble-api')
+
+	implementation project(':bramble-core')
+
+	implementation 'androidx.annotation:annotation:1.5.0'
+	implementation "org.briarproject:onionwrapper-android:$onionwrapper_version"
+
+	tor "org.briarproject:tor-android:$tor_version"
+	tor "org.briarproject:lyrebird-android:$lyrebird_version"
+
+	annotationProcessor "com.google.dagger:dagger-compiler:$dagger_version"
+
+	compileOnly 'javax.annotation:jsr250-api:1.0'
+
+	testImplementation project(path: ':bramble-api', configuration: 'testOutput')
+
+	testImplementation "junit:junit:$junit_version"
+	testImplementation "org.jmock:jmock:$jmock_version"
+	testImplementation "org.jmock:jmock-junit4:$jmock_version"
+	testImplementation "org.jmock:jmock-imposters:$jmock_version"
+}
+
+def torLibsDir = 'src/main/jniLibs'
+
+task cleanTorBinaries {
+	outputs.dir torLibsDir
+	doLast {
+		delete fileTree(torLibsDir)
+	}
+}
+
+clean.dependsOn cleanTorBinaries
+
+task unpackTorBinaries {
+	outputs.dir torLibsDir
+	doLast {
+		copy {
+			from configurations.tor.collect { zipTree(it) }
+			into torLibsDir
+		}
+	}
+	dependsOn cleanTorBinaries
+}
+
+preBuild.dependsOn unpackTorBinaries

bramble-android/proguard-rules.txt

+# Keep the H2 classes that are loaded via reflection
+-keep class org.h2.Driver { *; }
+-keep class org.h2.engine.Engine { *; }
+-keep class org.h2.store.fs.** { *; }
+# Don't warn about unused dependencies of H2 classes
+-dontwarn org.h2.**
+-dontnote org.h2.**
+
+-keep class dagger.** { *; }
+-dontwarn dagger.**
+-dontnote dagger.**
+
+-keep class net.i2p.crypto.eddsa.** { *; }
+
+-keep class org.whispersystems.curve25519.** { *; }
+
+-dontwarn sun.misc.Unsafe
+-dontnote com.google.common.**
+
+-dontwarn com.fasterxml.jackson.databind.ext.Java7SupportImpl
+
+# Keep all Jackson-serialisable classes and their members
+-keep interface com.fasterxml.jackson.databind.annotation.JsonSerialize
+-keep @com.fasterxml.jackson.databind.annotation.JsonSerialize class * { *; }

bramble-android/src/main/AndroidManifest.xml

+<manifest xmlns:android="http://schemas.android.com/apk/res/android"
+	xmlns:tools="http://schemas.android.com/tools"
+	package="org.briarproject.bramble">
+
+	<uses-feature
+		android:name="android.hardware.bluetooth"
+		android:required="false" />
+
+	<uses-permission android:name="android.permission.ACCESS_NETWORK_STATE" />
+	<uses-permission android:name="android.permission.ACCESS_WIFI_STATE" />
+	<!-- The BLUETOOTH permission was supposed to be removed in API 31 but is still needed on some Xiaomi/Redmi/POCO devices running API 31 and Nubia devices running API 32/33 -->
+	<uses-permission android:name="android.permission.BLUETOOTH" />
+	<uses-permission
+		android:name="android.permission.BLUETOOTH_ADMIN"
+		android:maxSdkVersion="30" />
+	<uses-permission
+		android:name="android.permission.BLUETOOTH_SCAN"
+		android:usesPermissionFlags="neverForLocation"
+		tools:targetApi="31" />
+	<uses-permission android:name="android.permission.BLUETOOTH_CONNECT" />
+	<uses-permission android:name="android.permission.BLUETOOTH_ADVERTISE" />
+	<uses-permission android:name="android.permission.INTERNET" />
+	<uses-permission android:name="android.permission.WAKE_LOCK" />
+
+	<application
+		android:allowBackup="false"
+		android:label="@string/app_name"
+		android:supportsRtl="true">
+
+		<receiver android:name=".system.AlarmReceiver" />
+
+	</application>
+
+</manifest>

bramble-android/src/main/java/org/briarproject/bramble/BrambleAndroidEagerSingletons.java

+package org.briarproject.bramble;
+
+import org.briarproject.bramble.battery.AndroidBatteryModule;
+import org.briarproject.bramble.network.AndroidNetworkModule;
+import org.briarproject.bramble.reporting.ReportingModule;
+
+public interface BrambleAndroidEagerSingletons {
+
+	void inject(AndroidBatteryModule.EagerSingletons init);
+
+	void inject(AndroidNetworkModule.EagerSingletons init);
+
+	void inject(ReportingModule.EagerSingletons init);
+
+	class Helper {
+
+		public static void injectEagerSingletons(
+				BrambleAndroidEagerSingletons c) {
+			c.inject(new AndroidBatteryModule.EagerSingletons());
+			c.inject(new AndroidNetworkModule.EagerSingletons());
+			c.inject(new ReportingModule.EagerSingletons());
+		}
+	}
+}

bramble-android/src/main/java/org/briarproject/bramble/BrambleAndroidModule.java

+package org.briarproject.bramble;
+
+import org.briarproject.bramble.battery.AndroidBatteryModule;
+import org.briarproject.bramble.io.DnsModule;
+import org.briarproject.bramble.network.AndroidNetworkModule;
+import org.briarproject.bramble.plugin.tor.CircumventionModule;
+import org.briarproject.bramble.reporting.ReportingModule;
+import org.briarproject.bramble.socks.SocksModule;
+import org.briarproject.bramble.system.AndroidSystemModule;
+import org.briarproject.bramble.system.AndroidTaskSchedulerModule;
+import org.briarproject.bramble.system.AndroidWakeLockModule;
+import org.briarproject.bramble.system.AndroidWakefulIoExecutorModule;
+import org.briarproject.bramble.system.DefaultThreadFactoryModule;
+
+import dagger.Module;
+
+@Module(includes = {
+		AndroidBatteryModule.class,
+		AndroidNetworkModule.class,
+		AndroidSystemModule.class,
+		AndroidTaskSchedulerModule.class,
+		AndroidWakefulIoExecutorModule.class,
+		AndroidWakeLockModule.class,
+		DefaultThreadFactoryModule.class,
+		CircumventionModule.class,
+		DnsModule.class,
+		ReportingModule.class,
+		SocksModule.class
+})
+public class BrambleAndroidModule {
+}

bramble-android/src/main/java/org/briarproject/bramble/BrambleAppComponent.java

+package org.briarproject.bramble;
+
+import org.briarproject.bramble.api.system.AlarmListener;
+
+public interface BrambleAppComponent {
+
+	AlarmListener alarmListener();
+}

bramble-android/src/main/java/org/briarproject/bramble/BrambleApplication.java

+package org.briarproject.bramble;
+
+public interface BrambleApplication {
+
+	BrambleAppComponent getBrambleAppComponent();
+}

bramble-android/src/main/java/org/briarproject/bramble/account/AndroidAccountManager.java

+package org.briarproject.bramble.account;
+
+import android.app.Application;
+import android.content.Context;
+import android.content.SharedPreferences;
+import android.preference.PreferenceManager;
+
+import org.briarproject.bramble.api.account.AccountManager;
+import org.briarproject.bramble.api.crypto.CryptoComponent;
+import org.briarproject.bramble.api.db.DatabaseConfig;
+import org.briarproject.bramble.api.identity.IdentityManager;
+
+import java.io.File;
+import java.util.HashSet;
+import java.util.List;
+import java.util.Set;
+import java.util.logging.Logger;
+
+import javax.annotation.Nullable;
+import javax.annotation.concurrent.GuardedBy;
+import javax.inject.Inject;
+
+import static java.util.Arrays.asList;
+import static java.util.logging.Level.INFO;
+import static org.briarproject.bramble.util.IoUtils.deleteFileOrDir;
+import static org.briarproject.bramble.util.LogUtils.logFileOrDir;
+
+class AndroidAccountManager extends AccountManagerImpl
+		implements AccountManager {
+
+	private static final Logger LOG =
+			Logger.getLogger(AndroidAccountManager.class.getName());
+
+	/**
+	 * Directories that shouldn't be deleted when deleting the user's account.
+	 */
+	private static final List<String> PROTECTED_DIR_NAMES =
+			asList("cache", "code_cache", "lib", "shared_prefs");
+
+	protected final Context appContext;
+	private final SharedPreferences prefs;
+
+	@Inject
+	AndroidAccountManager(DatabaseConfig databaseConfig,
+			CryptoComponent crypto, IdentityManager identityManager,
+			SharedPreferences prefs, Application app) {
+		super(databaseConfig, crypto, identityManager);
+		this.prefs = prefs;
+		appContext = app.getApplicationContext();
+	}
+
+	@Override
+	public boolean accountExists() {
+		boolean exists = super.accountExists();
+		if (!exists && LOG.isLoggable(INFO)) {
+			LOG.info("Account does not exist. Contents of account directory:");
+			logFileOrDir(LOG, INFO, getDataDir());
+		}
+		return exists;
+	}
+
+	@Override
+	public void deleteAccount() {
+		synchronized (stateChangeLock) {
+			if (LOG.isLoggable(INFO)) {
+				LOG.info("Contents of account directory before deleting:");
+				logFileOrDir(LOG, INFO, getDataDir());
+			}
+			super.deleteAccount();
+			SharedPreferences defaultPrefs = getDefaultSharedPreferences();
+			deleteAppData(prefs, defaultPrefs);
+			if (LOG.isLoggable(INFO)) {
+				LOG.info("Contents of account directory after deleting:");
+				logFileOrDir(LOG, INFO, getDataDir());
+			}
+		}
+	}
+
+	// Package access for testing
+	SharedPreferences getDefaultSharedPreferences() {
+		return PreferenceManager.getDefaultSharedPreferences(appContext);
+	}
+
+	@GuardedBy("stateChangeLock")
+	private void deleteAppData(SharedPreferences... clear) {
+		// Clear and commit shared preferences
+		for (SharedPreferences prefs : clear) {
+			if (!prefs.edit().clear().commit())
+				LOG.warning("Could not clear shared preferences");
+		}
+		// Delete files, except protected directories
+		Set<File> files = new HashSet<>();
+		File dataDir = getDataDir();
+		@Nullable
+		File[] fileArray = dataDir.listFiles();
+		if (fileArray == null) {
+			LOG.warning("Could not list files in app data dir");
+		} else {
+			for (File file : fileArray) {
+				if (!PROTECTED_DIR_NAMES.contains(file.getName())) {
+					files.add(file);
+				}
+			}
+		}
+		files.add(appContext.getFilesDir());
+		addIfNotNull(files, appContext.getExternalCacheDir());
+		for (File file : appContext.getExternalCacheDirs()) {
+			addIfNotNull(files, file);
+		}
+		for (File file : appContext.getExternalMediaDirs()) {
+			addIfNotNull(files, file);
+		}
+		// Clear the cache directory but don't delete it
+		File cacheDir = appContext.getCacheDir();
+		File[] children = cacheDir.listFiles();
+		if (children != null) files.addAll(asList(children));
+		for (File file : files) {
+			if (LOG.isLoggable(INFO)) {
+				LOG.info("Deleting " + file.getAbsolutePath());
+			}
+			deleteFileOrDir(file);
+		}
+	}
+
+	private File getDataDir() {
+		return new File(appContext.getApplicationInfo().dataDir);
+	}
+
+	private void addIfNotNull(Set<File> files, @Nullable File file) {
+		if (file != null) files.add(file);
+	}
+}

bramble-android/src/main/java/org/briarproject/bramble/api/system/AlarmListener.java

+package org.briarproject.bramble.api.system;
+
+import android.content.Intent;
+
+import org.briarproject.nullsafety.NotNullByDefault;
+
+@NotNullByDefault
+public interface AlarmListener {
+
+	void onAlarm(Intent intent);
+}

bramble-android/src/main/java/org/briarproject/bramble/api/system/AndroidExecutor.java

+package org.briarproject.bramble.api.system;
+
+import java.util.concurrent.Callable;
+import java.util.concurrent.Future;
+
+/**
+ * Enables background threads to make Android API calls that must be made from
+ * a thread with a message queue.
+ */
+public interface AndroidExecutor {
+
+	/**
+	 * Runs the given task on a background thread with a message queue and
+	 * returns a Future for getting the result.
+	 */
+	<V> Future<V> runOnBackgroundThread(Callable<V> c);
+
+	/**
+	 * Runs the given task on a background thread with a message queue.
+	 */
+	void runOnBackgroundThread(Runnable r);
+
+	/**
+	 * Runs the given task on the main UI thread and returns a Future for
+	 * getting the result.
+	 */
+	<V> Future<V> runOnUiThread(Callable<V> c);
+
+	/**
+	 * Runs the given task on the main UI thread.
+	 */
+	void runOnUiThread(Runnable r);
+}

bramble-android/src/main/java/org/briarproject/bramble/battery/AndroidBatteryManager.java

+package org.briarproject.bramble.battery;
+
+import android.app.Application;
+import android.content.BroadcastReceiver;
+import android.content.Context;
+import android.content.Intent;
+import android.content.IntentFilter;
+import android.os.PowerManager;
+
+import org.briarproject.bramble.api.battery.BatteryManager;
+import org.briarproject.bramble.api.battery.event.BatteryEvent;
+import org.briarproject.bramble.api.event.EventBus;
+import org.briarproject.bramble.api.lifecycle.Service;
+
+import java.util.concurrent.atomic.AtomicBoolean;
+import java.util.logging.Logger;
+
+import javax.inject.Inject;
+
+import androidx.annotation.RequiresApi;
+
+import static android.content.Intent.ACTION_BATTERY_CHANGED;
+import static android.content.Intent.ACTION_POWER_CONNECTED;
+import static android.content.Intent.ACTION_POWER_DISCONNECTED;
+import static android.os.BatteryManager.EXTRA_PLUGGED;
+import static android.os.Build.VERSION.SDK_INT;
+import static android.os.PowerManager.ACTION_DEVICE_IDLE_MODE_CHANGED;
+import static android.os.PowerManager.ACTION_DEVICE_LIGHT_IDLE_MODE_CHANGED;
+import static android.os.PowerManager.ACTION_LOW_POWER_STANDBY_ENABLED_CHANGED;
+import static android.os.PowerManager.ACTION_POWER_SAVE_MODE_CHANGED;
+import static java.util.logging.Level.INFO;
+import static java.util.logging.Logger.getLogger;
+import static org.briarproject.bramble.util.AndroidUtils.registerReceiver;
+
+class AndroidBatteryManager implements BatteryManager, Service {
+
+	private static final Logger LOG =
+			getLogger(AndroidBatteryManager.class.getName());
+
+	private final Context appContext;
+	private final EventBus eventBus;
+	private final AtomicBoolean used = new AtomicBoolean(false);
+
+	private volatile BroadcastReceiver batteryReceiver = null;
+
+	@Inject
+	AndroidBatteryManager(Application app, EventBus eventBus) {
+		this.appContext = app.getApplicationContext();
+		this.eventBus = eventBus;
+	}
+
+	@Override
+	public boolean isCharging() {
+		// Get the sticky intent for ACTION_BATTERY_CHANGED
+		IntentFilter filter = new IntentFilter(ACTION_BATTERY_CHANGED);
+		Intent i = registerReceiver(appContext, null, filter);
+		if (i == null) return false;
+		int status = i.getIntExtra(EXTRA_PLUGGED, 0);
+		return status != 0;
+	}
+
+	@Override
+	public void startService() {
+		if (used.getAndSet(true)) throw new IllegalStateException();
+		batteryReceiver = new BatteryReceiver();
+		IntentFilter filter = new IntentFilter();
+		filter.addAction(ACTION_POWER_CONNECTED);
+		filter.addAction(ACTION_POWER_DISCONNECTED);
+		filter.addAction(ACTION_POWER_SAVE_MODE_CHANGED);
+		if (SDK_INT >= 23) filter.addAction(ACTION_DEVICE_IDLE_MODE_CHANGED);
+		if (SDK_INT >= 33) {
+			filter.addAction(ACTION_LOW_POWER_STANDBY_ENABLED_CHANGED);
+			filter.addAction(ACTION_DEVICE_LIGHT_IDLE_MODE_CHANGED);
+		}
+		registerReceiver(appContext, batteryReceiver, filter);
+	}
+
+	@Override
+	public void stopService() {
+		if (batteryReceiver != null)
+			appContext.unregisterReceiver(batteryReceiver);
+	}
+
+	private class BatteryReceiver extends BroadcastReceiver {
+
+		@Override
+		public void onReceive(Context ctx, Intent i) {
+			String action = i.getAction();
+			if (LOG.isLoggable(INFO)) LOG.info("Received broadcast " + action);
+			if (ACTION_POWER_CONNECTED.equals(action))
+				eventBus.broadcast(new BatteryEvent(true));
+			else if (ACTION_POWER_DISCONNECTED.equals(action))
+				eventBus.broadcast(new BatteryEvent(false));
+			else if (SDK_INT >= 23 &&
+					ACTION_DEVICE_IDLE_MODE_CHANGED.equals(action) &&
+					LOG.isLoggable(INFO)) {
+				LOG.info("Device idle mode changed to: " +
+						getPowerManager(ctx).isDeviceIdleMode());
+			} else if (SDK_INT >= 23 &&
+					ACTION_POWER_SAVE_MODE_CHANGED.equals(action) &&
+					LOG.isLoggable(INFO)) {
+				LOG.info("Power save mode changed to: " +
+						getPowerManager(ctx).isPowerSaveMode());
+			} else if (SDK_INT >= 33 && LOG.isLoggable(INFO) &&
+					ACTION_LOW_POWER_STANDBY_ENABLED_CHANGED.equals(action)) {
+				PowerManager powerManager =
+						ctx.getSystemService(PowerManager.class);
+				LOG.info("Low power standby now is: " +
+						powerManager.isLowPowerStandbyEnabled());
+			} else if (SDK_INT >= 33 && LOG.isLoggable(INFO) &&
+					ACTION_DEVICE_LIGHT_IDLE_MODE_CHANGED.equals(action)) {
+				PowerManager powerManager = getPowerManager(ctx);
+				LOG.info("Light idle mode now is: " +
+						powerManager.isDeviceLightIdleMode());
+			}
+		}
+	}
+
+	@RequiresApi(api = 23)
+	private PowerManager getPowerManager(Context ctx) {
+		return ctx.getSystemService(PowerManager.class);
+	}
+}

bramble-android/src/main/java/org/briarproject/bramble/battery/AndroidBatteryModule.java

+package org.briarproject.bramble.battery;
+
+import org.briarproject.bramble.api.battery.BatteryManager;
+import org.briarproject.bramble.api.lifecycle.LifecycleManager;
+
+import javax.inject.Inject;
+import javax.inject.Singleton;
+
+import dagger.Module;
+import dagger.Provides;
+
+@Module
+public class AndroidBatteryModule {
+
+	public static class EagerSingletons {
+		@Inject
+		BatteryManager batteryManager;
+	}
+
+	@Provides
+	@Singleton
+	BatteryManager provideBatteryManager(LifecycleManager lifecycleManager,
+			AndroidBatteryManager batteryManager) {
+		lifecycleManager.registerService(batteryManager);
+		return batteryManager;
+	}
+}

bramble-android/src/main/java/org/briarproject/bramble/network/AndroidNetworkManager.java

+package org.briarproject.bramble.network;
+
+import android.annotation.TargetApi;
+import android.app.Application;
+import android.content.BroadcastReceiver;
+import android.content.Context;
+import android.content.Intent;
+import android.content.IntentFilter;
+import android.net.ConnectivityManager;
+import android.net.LinkAddress;
+import android.net.LinkProperties;
+import android.net.Network;
+import android.net.NetworkInfo;
+import android.net.wifi.WifiInfo;
+import android.net.wifi.WifiManager;
+
+import org.briarproject.bramble.api.Cancellable;
+import org.briarproject.bramble.api.event.EventBus;
+import org.briarproject.bramble.api.event.EventExecutor;
+import org.briarproject.bramble.api.lifecycle.Service;
+import org.briarproject.bramble.api.network.NetworkManager;
+import org.briarproject.bramble.api.network.NetworkStatus;
+import org.briarproject.bramble.api.network.event.NetworkStatusEvent;
+import org.briarproject.bramble.api.system.TaskScheduler;
+import org.briarproject.nullsafety.MethodsNotNullByDefault;
+import org.briarproject.nullsafety.ParametersNotNullByDefault;
+
+import java.net.Inet4Address;
+import java.net.InetAddress;
+import java.net.NetworkInterface;
+import java.net.SocketException;
+import java.util.Enumeration;
+import java.util.concurrent.Executor;
+import java.util.concurrent.TimeUnit;
+import java.util.concurrent.atomic.AtomicBoolean;
+import java.util.concurrent.atomic.AtomicReference;
+import java.util.logging.Logger;
+
+import javax.annotation.Nullable;
+import javax.inject.Inject;
+
+import static android.content.Context.CONNECTIVITY_SERVICE;
+import static android.content.Context.WIFI_SERVICE;
+import static android.content.Intent.ACTION_SCREEN_OFF;
+import static android.content.Intent.ACTION_SCREEN_ON;
+import static android.net.ConnectivityManager.CONNECTIVITY_ACTION;
+import static android.net.ConnectivityManager.TYPE_WIFI;
+import static android.net.wifi.p2p.WifiP2pManager.WIFI_P2P_THIS_DEVICE_CHANGED_ACTION;
+import static android.os.Build.VERSION.SDK_INT;
+import static android.os.PowerManager.ACTION_DEVICE_IDLE_MODE_CHANGED;
+import static java.net.NetworkInterface.getNetworkInterfaces;
+import static java.util.Collections.list;
+import static java.util.concurrent.TimeUnit.MINUTES;
+import static java.util.concurrent.TimeUnit.SECONDS;
+import static java.util.logging.Level.INFO;
+import static java.util.logging.Level.WARNING;
+import static java.util.logging.Logger.getLogger;
+import static org.briarproject.bramble.util.AndroidUtils.registerReceiver;
+import static org.briarproject.bramble.util.LogUtils.logException;
+import static org.briarproject.nullsafety.NullSafety.requireNonNull;
+
+@MethodsNotNullByDefault
+@ParametersNotNullByDefault
+class AndroidNetworkManager implements NetworkManager, Service {
+
+	private static final Logger LOG =
+			getLogger(AndroidNetworkManager.class.getName());
+
+	// See android.net.wifi.WifiManager
+	private static final String WIFI_AP_STATE_CHANGED_ACTION =
+			"android.net.wifi.WIFI_AP_STATE_CHANGED";
+
+	private final TaskScheduler scheduler;
+	private final EventBus eventBus;
+	private final Executor eventExecutor;
+	private final Application app;
+	private final ConnectivityManager connectivityManager;
+	private final AtomicReference<Cancellable> connectivityCheck =
+			new AtomicReference<>();
+	private final AtomicBoolean used = new AtomicBoolean(false);
+
+	private volatile BroadcastReceiver networkStateReceiver = null;
+
+	@Inject
+	AndroidNetworkManager(TaskScheduler scheduler, EventBus eventBus,
+			@EventExecutor Executor eventExecutor, Application app) {
+		this.scheduler = scheduler;
+		this.eventBus = eventBus;
+		this.eventExecutor = eventExecutor;
+		this.app = app;
+		connectivityManager = (ConnectivityManager)
+				requireNonNull(app.getSystemService(CONNECTIVITY_SERVICE));
+	}
+
+	@Override
+	public void startService() {
+		if (used.getAndSet(true)) throw new IllegalStateException();
+		// Register to receive network status events
+		networkStateReceiver = new NetworkStateReceiver();
+		IntentFilter filter = new IntentFilter();
+		filter.addAction(CONNECTIVITY_ACTION);
+		filter.addAction(ACTION_SCREEN_ON);
+		filter.addAction(ACTION_SCREEN_OFF);
+		filter.addAction(WIFI_AP_STATE_CHANGED_ACTION);
+		filter.addAction(WIFI_P2P_THIS_DEVICE_CHANGED_ACTION);
+		if (SDK_INT >= 23) filter.addAction(ACTION_DEVICE_IDLE_MODE_CHANGED);
+		registerReceiver(app, networkStateReceiver, filter);
+	}
+
+	@Override
+	public void stopService() {
+		if (networkStateReceiver != null)
+			app.unregisterReceiver(networkStateReceiver);
+	}
+
+	@Override
+	public NetworkStatus getNetworkStatus() {
+		// https://issuetracker.google.com/issues/175055271
+		try {
+			NetworkInfo net = connectivityManager.getActiveNetworkInfo();
+			boolean connected = net != null && net.isConnected();
+			// Research into Android's behavior to check network connectivity
+			// (https://code.briarproject.org/briar/public-mesh-research/-/issues/19)
+			// has shown that NetworkInfo#isConnected() returns true if the device
+			// is connected to any Wifi, independent of whether any specific IP
+			// address can be reached using it or any domain names can be resolved.
+			boolean wifi = false, ipv6Only = false;
+			if (connected) {
+				wifi = net.getType() == TYPE_WIFI;
+				if (SDK_INT >= 23) ipv6Only = isActiveNetworkIpv6Only();
+				else ipv6Only = areAllAvailableNetworksIpv6Only();
+			}
+			return new NetworkStatus(connected, wifi, ipv6Only);
+		} catch (SecurityException e) {
+			logException(LOG, WARNING, e);
+			// Without the ConnectivityManager we can't detect whether we have
+			// internet access. Assume we do, which is probably less harmful
+			// than assuming we don't. Likewise, assume the connection is
+			// IPv6-only. Fall back to the WifiManager to detect whether we
+			// have a wifi connection.
+			LOG.info("ConnectivityManager is broken, guessing connectivity");
+			boolean connected = true, wifi = false, ipv6Only = true;
+			WifiManager wm = (WifiManager) app.getSystemService(WIFI_SERVICE);
+			if (wm != null) {
+				WifiInfo info = wm.getConnectionInfo();
+				if (info != null && info.getIpAddress() != 0) {
+					LOG.info("Connected to wifi");
+					wifi = true;
+					ipv6Only = false;
+				}
+			}
+			return new NetworkStatus(connected, wifi, ipv6Only);
+		}
+	}
+
+	/**
+	 * Returns true if the
+	 * {@link ConnectivityManager#getActiveNetwork() active network} has an
+	 * IPv6 unicast address and no IPv4 addresses. The active network is
+	 * assumed not to be a loopback interface.
+	 */
+	@TargetApi(23)
+	private boolean isActiveNetworkIpv6Only() {
+		// https://issuetracker.google.com/issues/175055271
+		try {
+			Network net = connectivityManager.getActiveNetwork();
+			if (net == null) {
+				LOG.info("No active network");
+				return false;
+			}
+			LinkProperties props = connectivityManager.getLinkProperties(net);
+			if (props == null) {
+				LOG.info("No link properties for active network");
+				return false;
+			}
+			boolean hasIpv6Unicast = false;
+			for (LinkAddress linkAddress : props.getLinkAddresses()) {
+				InetAddress addr = linkAddress.getAddress();
+				if (addr instanceof Inet4Address) return false;
+				if (!addr.isMulticastAddress()) hasIpv6Unicast = true;
+			}
+			return hasIpv6Unicast;
+		} catch (SecurityException e) {
+			logException(LOG, WARNING, e);
+			return false;
+		}
+	}
+
+	/**
+	 * Returns true if the device has at least one network interface with an
+	 * IPv6 unicast address and no interfaces with IPv4 addresses, excluding
+	 * loopback interfaces and interfaces that are
+	 * {@link NetworkInterface#isUp() down}. If this method returns true and
+	 * the device has internet access then it's via IPv6 only.
+	 */
+	private boolean areAllAvailableNetworksIpv6Only() {
+		try {
+			Enumeration<NetworkInterface> interfaces = getNetworkInterfaces();
+			if (interfaces == null) {
+				LOG.info("No network interfaces");
+				return false;
+			}
+			boolean hasIpv6Unicast = false;
+			for (NetworkInterface i : list(interfaces)) {
+				if (i.isLoopback() || !i.isUp()) continue;
+				for (InetAddress addr : list(i.getInetAddresses())) {
+					if (addr instanceof Inet4Address) return false;
+					if (!addr.isMulticastAddress()) hasIpv6Unicast = true;
+				}
+			}
+			return hasIpv6Unicast;
+		} catch (SocketException e) {
+			logException(LOG, WARNING, e);
+			return false;
+		}
+	}
+
+	private void updateConnectionStatus() {
+		eventBus.broadcast(new NetworkStatusEvent(getNetworkStatus()));
+	}
+
+	private void scheduleConnectionStatusUpdate(int delay, TimeUnit unit) {
+		Cancellable newConnectivityCheck =
+				scheduler.schedule(this::updateConnectionStatus, eventExecutor,
+						delay, unit);
+		Cancellable oldConnectivityCheck =
+				connectivityCheck.getAndSet(newConnectivityCheck);
+		if (oldConnectivityCheck != null) oldConnectivityCheck.cancel();
+	}
+
+	private class NetworkStateReceiver extends BroadcastReceiver {
+
+		@Override
+		public void onReceive(Context ctx, Intent i) {
+			String action = i.getAction();
+			if (LOG.isLoggable(INFO)) LOG.info("Received broadcast " + action);
+			updateConnectionStatus();
+			if (isSleepOrDozeEvent(action)) {
+				// Allow time for the network to be enabled or disabled
+				scheduleConnectionStatusUpdate(1, MINUTES);
+			} else if (isApEvent(action)) {
+				// The state change may be broadcast before the AP address is
+				// visible, so delay handling the event
+				scheduleConnectionStatusUpdate(5, SECONDS);
+			}
+		}
+
+		private boolean isSleepOrDozeEvent(@Nullable String action) {
+			boolean isSleep = ACTION_SCREEN_ON.equals(action) ||
+					ACTION_SCREEN_OFF.equals(action);
+			boolean isDoze = SDK_INT >= 23 &&
+					ACTION_DEVICE_IDLE_MODE_CHANGED.equals(action);
+			return isSleep || isDoze;
+		}
+
+		private boolean isApEvent(@Nullable String action) {
+			return WIFI_AP_STATE_CHANGED_ACTION.equals(action) ||
+					WIFI_P2P_THIS_DEVICE_CHANGED_ACTION.equals(action);
+		}
+	}
+}

bramble-android/src/main/java/org/briarproject/bramble/network/AndroidNetworkModule.java

+package org.briarproject.bramble.network;
+
+import org.briarproject.bramble.api.lifecycle.LifecycleManager;
+import org.briarproject.bramble.api.network.NetworkManager;
+
+import javax.inject.Inject;
+import javax.inject.Singleton;
+
+import dagger.Module;
+import dagger.Provides;
+
+@Module
+public class AndroidNetworkModule {
+
+	public static class EagerSingletons {
+		@Inject
+		NetworkManager networkManager;
+	}
+
+	@Provides
+	@Singleton
+	NetworkManager provideNetworkManager(LifecycleManager lifecycleManager,
+			AndroidNetworkManager networkManager) {
+		lifecycleManager.registerService(networkManager);
+		return networkManager;
+	}
+}

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

+package org.briarproject.bramble.plugin.bluetooth;
+
+import android.bluetooth.BluetoothSocket;
+
+import org.briarproject.android.dontkillmelib.wakelock.AndroidWakeLockManager;
+import org.briarproject.bramble.api.io.TimeoutMonitor;
+import org.briarproject.bramble.api.plugin.duplex.DuplexPlugin;
+import org.briarproject.bramble.api.plugin.duplex.DuplexTransportConnection;
+import org.briarproject.nullsafety.NotNullByDefault;
+
+import java.io.IOException;
+
+@NotNullByDefault
+class AndroidBluetoothConnectionFactory
+		implements BluetoothConnectionFactory<BluetoothSocket> {
+
+	private final BluetoothConnectionLimiter connectionLimiter;
+	private final AndroidWakeLockManager wakeLockManager;
+	private final TimeoutMonitor timeoutMonitor;
+
+	AndroidBluetoothConnectionFactory(
+			BluetoothConnectionLimiter connectionLimiter,
+			AndroidWakeLockManager wakeLockManager,
+			TimeoutMonitor timeoutMonitor) {
+		this.connectionLimiter = connectionLimiter;
+		this.wakeLockManager = wakeLockManager;
+		this.timeoutMonitor = timeoutMonitor;
+	}
+
+	@Override
+	public DuplexTransportConnection wrapSocket(DuplexPlugin plugin,
+			BluetoothSocket s) throws IOException {
+		return new AndroidBluetoothTransportConnection(plugin,
+				connectionLimiter, wakeLockManager, timeoutMonitor, s);
+	}
+}