Try to use the real Bluetooth address on Android 6. #225

briar-android/src/org/briarproject/android/fragment/SettingsFragment.java

@@ -342,7 +342,7 @@ public class SettingsFragment extends BaseEventFragment implements
 			bluetoothSetting = !bluetoothSetting;
 			BluetoothAdapter adapter = BluetoothAdapter.getDefaultAdapter();
 			if (adapter != null) {
-				AndroidUtils.setBluetooth(adapter, bluetoothSetting);
+				AndroidUtils.enableBluetooth(adapter, bluetoothSetting);
 			}
 			storeBluetoothSettings();
 			displaySettings();

briar-android/src/org/briarproject/android/util/AndroidUtils.java

@@ -2,9 +2,13 @@ package org.briarproject.android.util;
 
 import android.annotation.SuppressLint;
 import android.bluetooth.BluetoothAdapter;
+import android.content.Context;
 import android.os.Build;
+import android.provider.Settings;
 import android.support.design.widget.TextInputLayout;
 
+import org.briarproject.util.StringUtils;
+
 import java.util.ArrayList;
 import java.util.Arrays;
 import java.util.Collection;
@@ -13,6 +17,9 @@ import java.util.List;
 
 public class AndroidUtils {
 
+	// Fake Bluetooth address returned by BluetoothAdapter on API 23 and later
+	private static final String FAKE_BLUETOOTH_ADDRESS = "02:00:00:00:00:00";
+
 	@SuppressLint("NewApi")
 	@SuppressWarnings("deprecation")
 	public static Collection<String> getSupportedArchitectures() {
@@ -26,7 +33,8 @@ public class AndroidUtils {
 		return Collections.unmodifiableList(abis);
 	}
 
-	public static void setError(TextInputLayout til, String error, boolean condition) {
+	public static void setError(TextInputLayout til, String error,
+			boolean condition) {
 		if (condition) {
 			if (til.getError() == null)
 				til.setError(error);
@@ -34,15 +42,34 @@ public class AndroidUtils {
 			til.setError(null);
 	}
 
-	public static void setBluetooth(final BluetoothAdapter adapter,
-			final boolean activate) {
-
+	public static void enableBluetooth(final BluetoothAdapter adapter,
+			final boolean enable) {
 		new Thread() {
 			@Override
 			public void run() {
-				if (activate) adapter.enable();
+				if (enable) adapter.enable();
 				else adapter.disable();
 			}
 		}.start();
 	}
+
+	public static String getBluetoothAddress(Context ctx,
+			BluetoothAdapter adapter) {
+		// Return the adapter's address if it's valid and not fake
+		String address = adapter.getAddress();
+		if (!StringUtils.isNullOrEmpty(address)
+				&& BluetoothAdapter.checkBluetoothAddress(address)
+				&& !address.equals(FAKE_BLUETOOTH_ADDRESS)) {
+			return address;
+		}
+		// Return the address from settings if it's valid
+		address = Settings.Secure.getString(ctx.getContentResolver(),
+				"bluetooth_address");
+		if (!StringUtils.isNullOrEmpty(address)
+				&& BluetoothAdapter.checkBluetoothAddress(address)) {
+			return address;
+		}
+		// As a last resort, return a fake but valid address
+		return FAKE_BLUETOOTH_ADDRESS;
+	}
 }

briar-android/src/org/briarproject/plugins/droidtooth/DroidtoothPlugin.java

@@ -9,6 +9,7 @@ import android.content.Context;
 import android.content.Intent;
 import android.content.IntentFilter;
 
+import org.briarproject.android.util.AndroidUtils;
 import org.briarproject.api.TransportId;
 import org.briarproject.api.android.AndroidExecutor;
 import org.briarproject.api.contact.ContactId;
@@ -152,11 +153,13 @@ class DroidtoothPlugin implements DuplexPlugin {
 		ioExecutor.execute(new Runnable() {
 			public void run() {
 				if (!isRunning()) return;
+				String address = AndroidUtils.getBluetoothAddress(appContext,
+						adapter);
 				if (LOG.isLoggable(INFO))
-					LOG.info("Local address " + adapter.getAddress());
+					LOG.info("Local address " + address);
 				// Advertise the Bluetooth address to contacts
 				TransportProperties p = new TransportProperties();
-				p.put("address", adapter.getAddress());
+				p.put("address", address);
 				callback.mergeLocalProperties(p);
 				// Bind a server socket to accept connections from contacts
 				BluetoothServerSocket ss;