Merge branch 'add-contacts-via-bluetooth' into 'master'

Add contacts via Bluetooth if possible

See merge request briar/briar!1292

bramble-api/src/main/java/org/briarproject/bramble/api/plugin/duplex/DuplexPlugin.java

@@ -41,12 +41,10 @@ public interface DuplexPlugin extends Plugin {
 	/**
 	 * Attempts to connect to the remote peer specified in the given descriptor.
 	 * Returns null if no connection can be established.
-	 *
-	 * @param alice True if the local party is Alice
 	 */
 	@Nullable
 	DuplexTransportConnection createKeyAgreementConnection(
-			byte[] remoteCommitment, BdfList descriptor, boolean alice);
+			byte[] remoteCommitment, BdfList descriptor);
 
 	/**
 	 * Returns true if the plugin supports rendezvous connections.

bramble-core/src/main/java/org/briarproject/bramble/keyagreement/KeyAgreementConnector.java

@@ -1,5 +1,6 @@
 package org.briarproject.bramble.keyagreement;
 
+import org.briarproject.bramble.api.Pair;
 import org.briarproject.bramble.api.crypto.KeyAgreementCrypto;
 import org.briarproject.bramble.api.crypto.KeyPair;
 import org.briarproject.bramble.api.data.BdfList;
@@ -8,6 +9,8 @@ import org.briarproject.bramble.api.keyagreement.KeyAgreementListener;
 import org.briarproject.bramble.api.keyagreement.Payload;
 import org.briarproject.bramble.api.keyagreement.TransportDescriptor;
 import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
+import org.briarproject.bramble.api.plugin.BluetoothConstants;
+import org.briarproject.bramble.api.plugin.LanTcpConstants;
 import org.briarproject.bramble.api.plugin.Plugin;
 import org.briarproject.bramble.api.plugin.PluginManager;
 import org.briarproject.bramble.api.plugin.TransportId;
@@ -19,7 +22,9 @@ import org.briarproject.bramble.api.record.RecordWriterFactory;
 import java.io.IOException;
 import java.io.InputStream;
 import java.util.ArrayList;
+import java.util.HashMap;
 import java.util.List;
+import java.util.Map;
 import java.util.concurrent.Callable;
 import java.util.concurrent.CopyOnWriteArrayList;
 import java.util.concurrent.CountDownLatch;
@@ -28,8 +33,10 @@ import java.util.logging.Logger;
 
 import javax.annotation.Nullable;
 
+import static java.util.Arrays.asList;
 import static java.util.logging.Level.INFO;
 import static java.util.logging.Level.WARNING;
+import static java.util.logging.Logger.getLogger;
 import static org.briarproject.bramble.api.keyagreement.KeyAgreementConstants.CONNECTION_TIMEOUT;
 import static org.briarproject.bramble.util.LogUtils.logException;
 
@@ -41,7 +48,10 @@ class KeyAgreementConnector {
 	}
 
 	private static final Logger LOG =
-			Logger.getLogger(KeyAgreementConnector.class.getName());
+			getLogger(KeyAgreementConnector.class.getName());
+
+	private static final List<TransportId> PREFERRED_TRANSPORTS =
+			asList(BluetoothConstants.ID, LanTcpConstants.ID);
 
 	private final Callbacks callbacks;
 	private final KeyAgreementCrypto keyAgreementCrypto;
@@ -105,24 +115,35 @@ class KeyAgreementConnector {
 		this.alice = alice;
 		aliceLatch.countDown();
 
-		// Start connecting over supported transports
+		// Start connecting over supported transports in order of preference
 		if (LOG.isLoggable(INFO)) {
 			LOG.info("Starting outgoing BQP connections as "
 					+ (alice ? "Alice" : "Bob"));
 		}
+		Map<TransportId, TransportDescriptor> descriptors = new HashMap<>();
 		for (TransportDescriptor d : remotePayload.getTransportDescriptors()) {
-			Plugin p = pluginManager.getPlugin(d.getId());
-			if (p instanceof DuplexPlugin) {
+			descriptors.put(d.getId(), d);
+		}
+		List<Pair<DuplexPlugin, BdfList>> transports = new ArrayList<>();
+		for (TransportId id : PREFERRED_TRANSPORTS) {
+			TransportDescriptor d = descriptors.get(id);
+			Plugin p = pluginManager.getPlugin(id);
+			if (d != null && p instanceof DuplexPlugin) {
 				if (LOG.isLoggable(INFO))
-					LOG.info("Connecting via " + d.getId());
-				DuplexPlugin plugin = (DuplexPlugin) p;
-				byte[] commitment = remotePayload.getCommitment();
-				BdfList descriptor = d.getDescriptor();
-				connectionChooser.submit(new ReadableTask(new ConnectorTask(
-						plugin, commitment, descriptor, alice)));
+					LOG.info("Connecting via " + id);
+				transports.add(new Pair<>((DuplexPlugin) p, d.getDescriptor()));
 			}
 		}
 
+		// TODO: If we don't have any transports in common with the peer,
+		//  warn the user and give up (#1224)
+
+		if (!transports.isEmpty()) {
+			byte[] commitment = remotePayload.getCommitment();
+			connectionChooser.submit(new ReadableTask(new ConnectorTask(
+					transports, commitment)));
+		}
+
 		// Get chosen connection
 		try {
 			KeyAgreementConnection chosen =
@@ -148,17 +169,13 @@ class KeyAgreementConnector {
 
 	private class ConnectorTask implements Callable<KeyAgreementConnection> {
 
-		private final DuplexPlugin plugin;
+		private final List<Pair<DuplexPlugin, BdfList>> transports;
 		private final byte[] commitment;
-		private final BdfList descriptor;
-		private final boolean alice;
 
-		private ConnectorTask(DuplexPlugin plugin, byte[] commitment,
-				BdfList descriptor, boolean alice) {
-			this.plugin = plugin;
+		private ConnectorTask(List<Pair<DuplexPlugin, BdfList>> transports,
+				byte[] commitment) {
+			this.transports = transports;
 			this.commitment = commitment;
-			this.descriptor = descriptor;
-			this.alice = alice;
 		}
 
 		@Nullable
@@ -166,13 +183,18 @@ class KeyAgreementConnector {
 		public KeyAgreementConnection call() throws Exception {
 			// Repeat attempts until we connect, get stopped, or get interrupted
 			while (!stopped) {
-				DuplexTransportConnection conn =
-						plugin.createKeyAgreementConnection(commitment,
-								descriptor, alice);
-				if (conn != null) {
-					if (LOG.isLoggable(INFO))
-						LOG.info(plugin.getId() + ": Outgoing connection");
-					return new KeyAgreementConnection(conn, plugin.getId());
+				for (Pair<DuplexPlugin, BdfList> pair : transports) {
+					if (stopped) return null;
+					DuplexPlugin plugin = pair.getFirst();
+					BdfList descriptor = pair.getSecond();
+					DuplexTransportConnection conn =
+							plugin.createKeyAgreementConnection(commitment,
+									descriptor);
+					if (conn != null) {
+						if (LOG.isLoggable(INFO))
+							LOG.info(plugin.getId() + ": Outgoing connection");
+						return new KeyAgreementConnection(conn, plugin.getId());
+					}
 				}
 				// Wait 2s before retry (to circumvent transient failures)
 				Thread.sleep(2000);

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

@@ -430,22 +430,17 @@ abstract class BluetoothPlugin<S, SS> implements DuplexPlugin, EventListener {
 
 	@Override
 	public DuplexTransportConnection createKeyAgreementConnection(
-			byte[] commitment, BdfList descriptor, boolean alice) {
+			byte[] commitment, BdfList descriptor) {
 		if (getState() != ACTIVE) return null;
 		// No truncation necessary because COMMIT_LENGTH = 16
 		String uuid = UUID.nameUUIDFromBytes(commitment).toString();
 		DuplexTransportConnection conn;
 		if (descriptor.size() == 1) {
-			if (alice) {
-				if (LOG.isLoggable(INFO)) {
-					LOG.info("Discovering address for key agreement UUID " +
-							uuid);
-				}
-				conn = discoverAndConnect(uuid);
-			} else {
-				LOG.info("No address in key agreement descriptor");
-				return null;
+			if (LOG.isLoggable(INFO)) {
+				LOG.info("Discovering address for key agreement UUID " +
+						uuid);
 			}
+			conn = discoverAndConnect(uuid);
 		} else {
 			String address;
 			try {

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

@@ -376,7 +376,7 @@ class LanTcpPlugin extends TcpPlugin {
 
 	@Override
 	public DuplexTransportConnection createKeyAgreementConnection(
-			byte[] commitment, BdfList descriptor, boolean alice) {
+			byte[] commitment, BdfList descriptor) {
 		ServerSocket ss = state.getServerSocket(true);
 		if (ss == null) return null;
 		InterfaceAddress local = getLocalInterfaceAddress(ss.getInetAddress());

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

@@ -367,7 +367,7 @@ abstract class TcpPlugin implements DuplexPlugin, EventListener {
 
 	@Override
 	public DuplexTransportConnection createKeyAgreementConnection(
-			byte[] commitment, BdfList descriptor, boolean alice) {
+			byte[] commitment, BdfList descriptor) {
 		throw new UnsupportedOperationException();
 	}
 

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

@@ -708,7 +708,7 @@ abstract class TorPlugin implements DuplexPlugin, EventHandler, EventListener {
 
 	@Override
 	public DuplexTransportConnection createKeyAgreementConnection(
-			byte[] commitment, BdfList descriptor, boolean alice) {
+			byte[] commitment, BdfList descriptor) {
 		throw new UnsupportedOperationException();
 	}
 

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

@@ -276,7 +276,7 @@ public class LanTcpPluginTest extends BrambleTestCase {
 		descriptor.add(local.getPort());
 		// Connect to the port
 		DuplexTransportConnection d = plugin.createKeyAgreementConnection(
-				new byte[COMMIT_LENGTH], descriptor, true);
+				new byte[COMMIT_LENGTH], descriptor);
 		assertNotNull(d);
 		// Check that the connection was accepted
 		assertTrue(latch.await(5, SECONDS));

bramble-java/src/main/java/org/briarproject/bramble/plugin/modem/ModemPlugin.java

@@ -198,7 +198,7 @@ class ModemPlugin implements DuplexPlugin, Modem.Callback {
 
 	@Override
 	public DuplexTransportConnection createKeyAgreementConnection(
-			byte[] commitment, BdfList descriptor, boolean alice) {
+			byte[] commitment, BdfList descriptor) {
 		throw new UnsupportedOperationException();
 	}
 

briar-android/src/main/java/org/briarproject/briar/android/keyagreement/ContactExchangeActivity.java

@@ -9,7 +9,6 @@ import org.briarproject.bramble.api.nullsafety.MethodsNotNullByDefault;
 import org.briarproject.bramble.api.nullsafety.ParametersNotNullByDefault;
 import org.briarproject.briar.R;
 import org.briarproject.briar.android.activity.ActivityComponent;
-import org.briarproject.briar.android.fragment.BaseFragment;
 
 import javax.annotation.Nullable;
 import javax.inject.Inject;
@@ -114,9 +113,7 @@ public class ContactExchangeActivity extends KeyAgreementActivity {
 		return getString(R.string.exchanging_contact_details);
 	}
 
-	protected void showErrorFragment() {
-		String errorMsg = getString(R.string.connection_error_explanation);
-		BaseFragment f = ContactExchangeErrorFragment.newInstance(errorMsg);
-		showNextFragment(f);
+	private void showErrorFragment() {
+		showNextFragment(new ContactExchangeErrorFragment());
 	}
 }

briar-android/src/main/java/org/briarproject/briar/android/keyagreement/ContactExchangeErrorFragment.java

@@ -1,5 +1,6 @@
 package org.briarproject.briar.android.keyagreement;
 
+import android.content.Intent;
 import android.os.Bundle;
 import android.view.LayoutInflater;
 import android.view.View;
@@ -18,7 +19,10 @@ import org.briarproject.briar.android.util.UiUtils;
 import javax.inject.Inject;
 
 import androidx.annotation.Nullable;
+import androidx.fragment.app.FragmentActivity;
 
+import static android.content.Intent.FLAG_ACTIVITY_CLEAR_TOP;
+import static android.view.View.GONE;
 import static org.briarproject.briar.android.util.UiUtils.onSingleLinkClick;
 
 @MethodsNotNullByDefault
@@ -58,13 +62,12 @@ public class ContactExchangeErrorFragment extends BaseFragment {
 		View v = inflater.inflate(R.layout.fragment_error_contact_exchange,
 				container, false);
 
-		// set humanized error message
+		// set optional error message
 		TextView explanation = v.findViewById(R.id.errorMessage);
 		Bundle args = getArguments();
-		if (args == null) {
-			throw new IllegalArgumentException("Use newInstance()");
-		}
-		explanation.setText(args.getString(ERROR_MSG));
+		String errorMessage = args == null ? null : args.getString(ERROR_MSG);
+		if (errorMessage == null) explanation.setVisibility(GONE);
+		else explanation.setText(args.getString(ERROR_MSG));
 
 		// make feedback link clickable
 		TextView sendFeedback = v.findViewById(R.id.sendFeedback);
@@ -73,7 +76,11 @@ public class ContactExchangeErrorFragment extends BaseFragment {
 		// buttons
 		Button tryAgain = v.findViewById(R.id.tryAgainButton);
 		tryAgain.setOnClickListener(view -> {
-			if (getActivity() != null) getActivity().onBackPressed();
+			// Recreate the activity so we return to the intro fragment
+			FragmentActivity activity = requireActivity();
+			Intent i = new Intent(activity, ContactExchangeActivity.class);
+			i.setFlags(FLAG_ACTIVITY_CLEAR_TOP);
+			activity.startActivity(i);
 		});
 		Button cancel = v.findViewById(R.id.cancelButton);
 		cancel.setOnClickListener(view -> finish());

briar-android/src/main/java/org/briarproject/briar/android/keyagreement/KeyAgreementActivity.java

@@ -26,7 +26,6 @@ import org.briarproject.briar.android.fragment.BaseFragment;
 import org.briarproject.briar.android.fragment.BaseFragment.BaseFragmentListener;
 import org.briarproject.briar.android.keyagreement.IntroFragment.IntroScreenSeenListener;
 import org.briarproject.briar.android.keyagreement.KeyAgreementFragment.KeyAgreementEventListener;
-import org.briarproject.briar.android.util.UiUtils;
 
 import java.util.logging.Logger;
 
@@ -46,6 +45,7 @@ import static android.bluetooth.BluetoothAdapter.ACTION_REQUEST_DISCOVERABLE;
 import static android.bluetooth.BluetoothAdapter.ACTION_SCAN_MODE_CHANGED;
 import static android.bluetooth.BluetoothAdapter.SCAN_MODE_CONNECTABLE_DISCOVERABLE;
 import static android.content.pm.PackageManager.PERMISSION_GRANTED;
+import static android.os.Build.VERSION.SDK_INT;
 import static java.util.logging.Level.INFO;
 import static java.util.logging.Logger.getLogger;
 import static org.briarproject.bramble.api.nullsafety.NullSafety.requireNonNull;
@@ -55,6 +55,7 @@ import static org.briarproject.bramble.api.plugin.Plugin.State.INACTIVE;
 import static org.briarproject.bramble.api.plugin.Plugin.State.STARTING_STOPPING;
 import static org.briarproject.briar.android.activity.RequestCodes.REQUEST_BLUETOOTH_DISCOVERABLE;
 import static org.briarproject.briar.android.activity.RequestCodes.REQUEST_PERMISSION_CAMERA_LOCATION;
+import static org.briarproject.briar.android.util.UiUtils.getGoToSettingsListener;
 
 @MethodsNotNullByDefault
 @ParametersNotNullByDefault
@@ -133,6 +134,8 @@ public abstract class KeyAgreementActivity extends BriarActivity implements
 	private Permission locationPermission = Permission.UNKNOWN;
 	private BluetoothDecision bluetoothDecision = BluetoothDecision.UNKNOWN;
 	private BroadcastReceiver bluetoothReceiver = null;
+	private Plugin wifiPlugin = null, bluetoothPlugin = null;
+	private BluetoothAdapter bt = null;
 
 	@Override
 	public void injectActivity(ActivityComponent component) {
@@ -152,6 +155,9 @@ public abstract class KeyAgreementActivity extends BriarActivity implements
 		IntentFilter filter = new IntentFilter(ACTION_SCAN_MODE_CHANGED);
 		bluetoothReceiver = new BluetoothStateReceiver();
 		registerReceiver(bluetoothReceiver, filter);
+		wifiPlugin = pluginManager.getPlugin(LanTcpConstants.ID);
+		bluetoothPlugin = pluginManager.getPlugin(BluetoothConstants.ID);
+		bt = BluetoothAdapter.getDefaultAdapter();
 	}
 
 	@Override
@@ -187,6 +193,7 @@ public abstract class KeyAgreementActivity extends BriarActivity implements
 		showQrCodeFragmentIfAllowed();
 	}
 
+	@SuppressWarnings("StatementWithEmptyBody")
 	private void showQrCodeFragmentIfAllowed() {
 		if (isResumed && continueClicked && areEssentialPermissionsGranted()) {
 			if (isWifiReady() && isBluetoothReady()) {
@@ -200,6 +207,8 @@ public abstract class KeyAgreementActivity extends BriarActivity implements
 				}
 				if (bluetoothDecision == BluetoothDecision.UNKNOWN) {
 					requestBluetoothDiscoverable();
+				} else if (bluetoothDecision == BluetoothDecision.REFUSED) {
+					// Ask again when the user clicks "continue"
 				} else if (shouldEnableBluetooth()) {
 					LOG.info("Enabling Bluetooth plugin");
 					hasEnabledBluetooth = true;
@@ -210,55 +219,50 @@ public abstract class KeyAgreementActivity extends BriarActivity implements
 	}
 
 	private boolean areEssentialPermissionsGranted() {
-		// If the camera permission has been granted, and the location
-		// permission has been granted or permanently denied, we can continue
 		return cameraPermission == Permission.GRANTED &&
-				(locationPermission == Permission.GRANTED ||
-						locationPermission == Permission.PERMANENTLY_DENIED);
+				(SDK_INT < 23 || locationPermission == Permission.GRANTED ||
+						!isBluetoothSupported());
+	}
+
+	private boolean isBluetoothSupported() {
+		return bt != null && bluetoothPlugin != null;
 	}
 
 	private boolean isWifiReady() {
-		Plugin p = pluginManager.getPlugin(LanTcpConstants.ID);
-		if (p == null) return true; // Continue without wifi
-		State state = p.getState();
+		if (wifiPlugin == null) return true; // Continue without wifi
+		State state = wifiPlugin.getState();
 		// Wait for plugin to become enabled
 		return state == ACTIVE || state == INACTIVE;
 	}
 
 	private boolean isBluetoothReady() {
-		if (bluetoothDecision == BluetoothDecision.UNKNOWN ||
-				bluetoothDecision == BluetoothDecision.WAITING) {
-			// Wait for decision
-			return false;
-		}
-		if (bluetoothDecision == BluetoothDecision.NO_ADAPTER
-				|| bluetoothDecision == BluetoothDecision.REFUSED) {
+		if (!isBluetoothSupported()) {
 			// Continue without Bluetooth
 			return true;
 		}
-		BluetoothAdapter bt = BluetoothAdapter.getDefaultAdapter();
-		if (bt == null) return true; // Continue without Bluetooth
+		if (bluetoothDecision == BluetoothDecision.UNKNOWN ||
+				bluetoothDecision == BluetoothDecision.WAITING ||
+				bluetoothDecision == BluetoothDecision.REFUSED) {
+			// Wait for user to accept
+			return false;
+		}
 		if (bt.getScanMode() != SCAN_MODE_CONNECTABLE_DISCOVERABLE) {
 			// Wait for adapter to become discoverable
 			return false;
 		}
-		Plugin p = pluginManager.getPlugin(BluetoothConstants.ID);
-		if (p == null) return true; // Continue without Bluetooth
 		// Wait for plugin to become active
-		return p.getState() == ACTIVE;
+		return bluetoothPlugin.getState() == ACTIVE;
 	}
 
 	private boolean shouldEnableWifi() {
 		if (hasEnabledWifi) return false;
-		Plugin p = pluginManager.getPlugin(LanTcpConstants.ID);
-		if (p == null) return false;
-		State state = p.getState();
+		if (wifiPlugin == null) return false;
+		State state = wifiPlugin.getState();
 		return state == STARTING_STOPPING || state == DISABLED;
 	}
 
 	private void requestBluetoothDiscoverable() {
-		BluetoothAdapter bt = BluetoothAdapter.getDefaultAdapter();
-		if (bt == null) {
+		if (!isBluetoothSupported()) {
 			bluetoothDecision = BluetoothDecision.NO_ADAPTER;
 			showQrCodeFragmentIfAllowed();
 		} else {
@@ -277,9 +281,8 @@ public abstract class KeyAgreementActivity extends BriarActivity implements
 	private boolean shouldEnableBluetooth() {
 		if (bluetoothDecision != BluetoothDecision.ACCEPTED) return false;
 		if (hasEnabledBluetooth) return false;
-		Plugin p = pluginManager.getPlugin(BluetoothConstants.ID);
-		if (p == null) return false;
-		State state = p.getState();
+		if (!isBluetoothSupported()) return false;
+		State state = bluetoothPlugin.getState();
 		return state == STARTING_STOPPING || state == DISABLED;
 	}
 
@@ -298,6 +301,9 @@ public abstract class KeyAgreementActivity extends BriarActivity implements
 	@Override
 	public void showNextScreen() {
 		continueClicked = true;
+		if (bluetoothDecision == BluetoothDecision.REFUSED) {
+			bluetoothDecision = BluetoothDecision.UNKNOWN; // Ask again
+		}
 		if (checkPermissions()) showQrCodeFragmentIfAllowed();
 	}
 
@@ -341,17 +347,17 @@ public abstract class KeyAgreementActivity extends BriarActivity implements
 
 	private boolean checkPermissions() {
 		if (areEssentialPermissionsGranted()) return true;
-		// If the camera permission has been permanently denied, ask the
+		// If an essential permission has been permanently denied, ask the
 		// user to change the setting
 		if (cameraPermission == Permission.PERMANENTLY_DENIED) {
-			Builder builder = new Builder(this, R.style.BriarDialogTheme);
-			builder.setTitle(R.string.permission_camera_title);
-			builder.setMessage(R.string.permission_camera_denied_body);
-			builder.setPositiveButton(R.string.ok,
-					UiUtils.getGoToSettingsListener(this));
-			builder.setNegativeButton(R.string.cancel,
-					(dialog, which) -> supportFinishAfterTransition());
-			builder.show();
+			showDenialDialog(R.string.permission_camera_title,
+					R.string.permission_camera_denied_body);
+			return false;
+		}
+		if (isBluetoothSupported() &&
+				locationPermission == Permission.PERMANENTLY_DENIED) {
+			showDenialDialog(R.string.permission_location_title,
+					R.string.permission_location_denied_body);
 			return false;
 		}
 		// Should we show the rationale for one or both permissions?
@@ -371,6 +377,16 @@ public abstract class KeyAgreementActivity extends BriarActivity implements
 		return false;
 	}
 
+	private void showDenialDialog(@StringRes int title, @StringRes int body) {
+		Builder builder = new Builder(this, R.style.BriarDialogTheme);
+		builder.setTitle(title);
+		builder.setMessage(body);
+		builder.setPositiveButton(R.string.ok, getGoToSettingsListener(this));
+		builder.setNegativeButton(R.string.cancel,
+				(dialog, which) -> supportFinishAfterTransition());
+		builder.show();
+	}
+
 	private void showRationale(@StringRes int title, @StringRes int body) {
 		Builder builder = new Builder(this, R.style.BriarDialogTheme);
 		builder.setTitle(title);
@@ -381,8 +397,13 @@ public abstract class KeyAgreementActivity extends BriarActivity implements
 	}
 
 	private void requestPermissions() {
-		ActivityCompat.requestPermissions(this,
-				new String[] {CAMERA, ACCESS_FINE_LOCATION},
+		String[] permissions;
+		if (isBluetoothSupported()) {
+			permissions = new String[] {CAMERA, ACCESS_FINE_LOCATION};
+		} else {
+			permissions = new String[] {CAMERA};
+		}
+		ActivityCompat.requestPermissions(this, permissions,
 				REQUEST_PERMISSION_CAMERA_LOCATION);
 	}
 
@@ -399,12 +420,15 @@ public abstract class KeyAgreementActivity extends BriarActivity implements
 		} else {
 			cameraPermission = Permission.PERMANENTLY_DENIED;
 		}
-		if (gotPermission(ACCESS_FINE_LOCATION, permissions, grantResults)) {
-			locationPermission = Permission.GRANTED;
-		} else if (shouldShowRationale(ACCESS_FINE_LOCATION)) {
-			locationPermission = Permission.SHOW_RATIONALE;
-		} else {
-			locationPermission = Permission.PERMANENTLY_DENIED;
+		if (isBluetoothSupported()) {
+			if (gotPermission(ACCESS_FINE_LOCATION, permissions,
+					grantResults)) {
+				locationPermission = Permission.GRANTED;
+			} else if (shouldShowRationale(ACCESS_FINE_LOCATION)) {
+				locationPermission = Permission.SHOW_RATIONALE;
+			} else {
+				locationPermission = Permission.PERMANENTLY_DENIED;
+			}
 		}
 		// If a permission dialog has been shown, showing the QR code fragment
 		// on this call path would cause a crash due to

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

@@ -210,7 +210,6 @@
 	<string name="connecting_to_device">Connecting to device\u2026</string>
 	<string name="authenticating_with_device">Authenticating with device\u2026</string>
 	<string name="connection_error_title">Could not connect to your contact</string>
-	<string name="connection_error_explanation">Please check that you\'re both connected to the same Wi-Fi network.</string>
 	<string name="connection_error_feedback">If this problem persists, please <a href="feedback">send feedback</a> to help us improve the app.</string>
 
 	<!-- Adding Contacts Remotely -->
@@ -589,6 +588,7 @@
 	<string name="permission_camera_location_title">Camera and location</string>
 	<string name="permission_camera_location_request_body">To scan the QR code, Briar needs access to the camera.\n\nTo discover Bluetooth devices, Briar needs permission to access your location.\n\nBriar does not store your location or share it with anyone.</string>
 	<string name="permission_camera_denied_body">You have denied access to the camera, but adding contacts requires using the camera.\n\nPlease consider granting access.</string>
+	<string name="permission_location_denied_body">You have denied access to your location, but Briar needs this permission to discover Bluetooth devices.\n\nPlease consider granting access.</string>
 	<string name="qr_code">QR code</string>
 	<string name="show_qr_code_fullscreen">Show QR code fullscreen</string>