Run contact exchange task on IO executor.

bramble-api/src/main/java/org/briarproject/bramble/api/contact/ContactExchangeTask.java

@@ -38,10 +38,15 @@ public interface ContactExchangeTask {
 	 */
 	String BOB_NONCE_LABEL = "org.briarproject.bramble.contact/BOB_NONCE";
 
+	/**
+	 * Label for signing key binding nonces.
+	 */
+	String SIGNING_LABEL = "org.briarproject.briar.contact/EXCHANGE";
+
 	/**
 	 * Exchanges contact information with a remote peer.
 	 */
-	void startExchange(LocalAuthor localAuthor, SecretKey masterKey,
+	void exchangeContacts(LocalAuthor localAuthor, SecretKey masterKey,
 			DuplexTransportConnection conn, TransportId transportId,
 			boolean alice);
 }

bramble-core/src/main/java/org/briarproject/bramble/contact/ContactExchangeTaskImpl.java

@@ -46,6 +46,7 @@ import java.util.logging.Logger;
 import javax.inject.Inject;
 
 import static java.util.logging.Level.WARNING;
+import static java.util.logging.Logger.getLogger;
 import static org.briarproject.bramble.api.contact.RecordTypes.CONTACT_INFO;
 import static org.briarproject.bramble.api.identity.AuthorConstants.MAX_SIGNATURE_LENGTH;
 import static org.briarproject.bramble.util.LogUtils.logException;
@@ -54,13 +55,10 @@ import static org.briarproject.bramble.util.ValidationUtils.checkSize;
 
 @MethodsNotNullByDefault
 @ParametersNotNullByDefault
-class ContactExchangeTaskImpl extends Thread implements ContactExchangeTask {
+class ContactExchangeTaskImpl implements ContactExchangeTask {
 
 	private static final Logger LOG =
-			Logger.getLogger(ContactExchangeTaskImpl.class.getName());
+			getLogger(ContactExchangeTaskImpl.class.getName());
-
-	private static final String SIGNING_LABEL_EXCHANGE =
-			"org.briarproject.briar.contact/EXCHANGE";
 
 	// Accept records with current protocol version, known record type
 	private static final Predicate<Record> ACCEPT = r ->
@@ -89,12 +87,6 @@ class ContactExchangeTaskImpl extends Thread implements ContactExchangeTask {
 	private final StreamReaderFactory streamReaderFactory;
 	private final StreamWriterFactory streamWriterFactory;
 
-	private volatile LocalAuthor localAuthor;
-	private volatile DuplexTransportConnection conn;
-	private volatile TransportId transportId;
-	private volatile SecretKey masterKey;
-	private volatile boolean alice;
-
 	@Inject
 	ContactExchangeTaskImpl(DatabaseComponent db, ClientHelper clientHelper,
 			RecordReaderFactory recordReaderFactory,
@@ -119,19 +111,9 @@ class ContactExchangeTaskImpl extends Thread implements ContactExchangeTask {
 	}
 
 	@Override
-	public void startExchange(LocalAuthor localAuthor, SecretKey masterKey,
+	public void exchangeContacts(LocalAuthor localAuthor,
-			DuplexTransportConnection conn, TransportId transportId,
+			SecretKey masterKey, DuplexTransportConnection conn,
-			boolean alice) {
+			TransportId transportId, boolean alice) {
-		this.localAuthor = localAuthor;
-		this.conn = conn;
-		this.transportId = transportId;
-		this.masterKey = masterKey;
-		this.alice = alice;
-		start();
-	}
-
-	@Override
-	public void run() {
 		// Get the transport connection's input and output streams
 		InputStream in;
 		OutputStream out;
@@ -195,13 +177,11 @@ class ContactExchangeTaskImpl extends Thread implements ContactExchangeTask {
 			if (alice) {
 				sendContactInfo(recordWriter, localAuthor, localProperties,
 						localSignature, localTimestamp);
-				recordWriter.flush();
 				remoteInfo = receiveContactInfo(recordReader);
 			} else {
 				remoteInfo = receiveContactInfo(recordReader);
 				sendContactInfo(recordWriter, localAuthor, localProperties,
 						localSignature, localTimestamp);
-				recordWriter.flush();
 			}
 			// Send EOF on the outgoing stream
 			streamWriter.sendEndOfStream();
@@ -227,8 +207,8 @@ class ContactExchangeTaskImpl extends Thread implements ContactExchangeTask {
 
 		try {
 			// Add the contact
-			ContactId contactId = addContact(remoteInfo.author, timestamp,
+			ContactId contactId = addContact(remoteInfo.author, localAuthor,
-					remoteInfo.properties);
+					masterKey, timestamp, alice, remoteInfo.properties);
 			// Reuse the connection as a transport connection
 			connectionManager.manageOutgoingConnection(contactId, transportId,
 					conn);
@@ -250,8 +230,7 @@ class ContactExchangeTaskImpl extends Thread implements ContactExchangeTask {
 
 	private byte[] sign(LocalAuthor author, byte[] nonce) {
 		try {
-			return crypto.sign(SIGNING_LABEL_EXCHANGE, nonce,
+			return crypto.sign(SIGNING_LABEL, nonce, author.getPrivateKey());
-					author.getPrivateKey());
 		} catch (GeneralSecurityException e) {
 			throw new AssertionError();
 		}
@@ -259,8 +238,8 @@ class ContactExchangeTaskImpl extends Thread implements ContactExchangeTask {
 
 	private boolean verify(Author author, byte[] nonce, byte[] signature) {
 		try {
-			return crypto.verifySignature(signature, SIGNING_LABEL_EXCHANGE,
+			return crypto.verifySignature(signature, SIGNING_LABEL, nonce,
-					nonce, author.getPublicKey());
+					author.getPublicKey());
 		} catch (GeneralSecurityException e) {
 			return false;
 		}
@@ -274,6 +253,7 @@ class ContactExchangeTaskImpl extends Thread implements ContactExchangeTask {
 		BdfList payload = BdfList.of(authorList, props, signature, timestamp);
 		recordWriter.writeRecord(new Record(PROTOCOL_VERSION, CONTACT_INFO,
 				clientHelper.toByteArray(payload)));
+		recordWriter.flush();
 		LOG.info("Sent contact info");
 	}
 
@@ -295,7 +275,8 @@ class ContactExchangeTaskImpl extends Thread implements ContactExchangeTask {
 		return new ContactInfo(author, properties, signature, timestamp);
 	}
 
-	private ContactId addContact(Author remoteAuthor, long timestamp,
+	private ContactId addContact(Author remoteAuthor, LocalAuthor localAuthor,
+			SecretKey masterKey, long timestamp, boolean alice,
 			Map<TransportId, TransportProperties> remoteProperties)
 			throws DbException {
 		return db.transactionWithResult(false, txn -> {

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

@@ -14,11 +14,13 @@ import org.briarproject.bramble.api.identity.Author;
 import org.briarproject.bramble.api.identity.IdentityManager;
 import org.briarproject.bramble.api.identity.LocalAuthor;
 import org.briarproject.bramble.api.keyagreement.KeyAgreementResult;
+import org.briarproject.bramble.api.lifecycle.IoExecutor;
 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 java.util.concurrent.Executor;
 import java.util.logging.Logger;
 
 import javax.annotation.Nullable;
@@ -36,6 +38,10 @@ public class ContactExchangeActivity extends KeyAgreementActivity implements
 	private static final Logger LOG =
 			Logger.getLogger(ContactExchangeActivity.class.getName());
 
+	@Inject
+	@IoExecutor
+	Executor ioExecutor;
+
 	// Fields that are accessed from background threads must be volatile
 	@Inject
 	volatile ContactExchangeTask contactExchangeTask;
@@ -63,12 +69,12 @@ public class ContactExchangeActivity extends KeyAgreementActivity implements
 	@Override
 	protected void onStop() {
 		super.onStop();
-		// Stop listen to updates from contactExchangeTask
+		// Stop listening to updates from contactExchangeTask
 		eventBus.addListener(this);
 	}
 
 	private void startContactExchange(KeyAgreementResult result) {
-		runOnDbThread(() -> {
+		ioExecutor.execute(() -> {
 			LocalAuthor localAuthor;
 			// Load the local pseudonym
 			try {
@@ -78,9 +84,8 @@ public class ContactExchangeActivity extends KeyAgreementActivity implements
 				contactExchangeFailed();
 				return;
 			}
-
 			// Exchange contact details
-			contactExchangeTask.startExchange(localAuthor,
+			contactExchangeTask.exchangeContacts(localAuthor,
 					result.getMasterKey(), result.getConnection(),
 					result.getTransportId(), result.wasAlice());
 		});