Advertise paired status to fix iOS9

iOS9 requires that homekit accessories advertise their paired status. It seems like Apple is enforcing a single user being paired with an accessory. However, it's not entirely clear, so the fix does not involve refactoring HomekitAuthInfo around a single user. Instead, HomekitAuthInfo now includes a hasUser method that should be implemented.

Author: andylintner

src/main/java/com/beowulfe/hap/HomekitAuthInfo.java

@@ -69,4 +69,13 @@ public interface HomekitAuthInfo {
 	 * @return the previously stored public key for this user.
 	 */
 	byte[] getUserPublicKey(String username);
+	
+	/**
+	 * Called to check if a user has been created. The homekit accessory advertises whether the accessory has already been paired.
+	 * At this time, it's unclear whether multiple users can be created, however it is known that advertising as unpaired
+	 * will break in iOS 9. The default value has been provided to maintain API compatibility for implementations targeting iOS 8.
+	 * 
+	 * @return whether a user has been created and stored
+	 */
+	default boolean hasUser() { return false; };
 }

src/main/java/com/beowulfe/hap/HomekitRoot.java

@@ -98,8 +98,9 @@ public void start() {
 		started = true;
 		registry.reset();
 		webHandler.start(new HomekitClientConnectionFactoryImpl(authInfo,
-				registry, subscriptions)).thenAccept(port -> {
+				registry, subscriptions, advertiser)).thenAccept(port -> {
 					try {
+						advertiser.setDiscoverable(authInfo.hasUser());
 						advertiser.advertise(label, authInfo.getMac(), port);
 					} catch (Exception e) {
 						throw new RuntimeException(e);

src/main/java/com/beowulfe/hap/impl/connections/ConnectionImpl.java

@@ -18,6 +18,7 @@
 import com.beowulfe.hap.impl.http.HomekitClientConnection;
 import com.beowulfe.hap.impl.http.HttpRequest;
 import com.beowulfe.hap.impl.http.HttpResponse;
+import com.beowulfe.hap.impl.jmdns.JmdnsHomekitAdvertiser;
 import com.beowulfe.hap.impl.pairing.UpgradeResponse;
 
 class ConnectionImpl implements HomekitClientConnection {
@@ -35,8 +36,9 @@ class ConnectionImpl implements HomekitClientConnection {
 	private final static Logger LOGGER = LoggerFactory.getLogger(HomekitClientConnection.class);
 
 	public ConnectionImpl(HomekitAuthInfo authInfo, HomekitRegistry registry, 
-			Consumer<HttpResponse> outOfBandMessageCallback, SubscriptionManager subscriptions) {
-		httpSession = new HttpSession(authInfo, registry, subscriptions, this);
+			Consumer<HttpResponse> outOfBandMessageCallback, SubscriptionManager subscriptions,
+			JmdnsHomekitAdvertiser advertiser) {
+		httpSession = new HttpSession(authInfo, registry, subscriptions, this, advertiser);
 		this.outOfBandMessageCallback = outOfBandMessageCallback;
 		this.subscriptions = subscriptions;
 	}

src/main/java/com/beowulfe/hap/impl/connections/HomekitClientConnectionFactoryImpl.java

@@ -7,23 +7,26 @@
 import com.beowulfe.hap.impl.http.HomekitClientConnection;
 import com.beowulfe.hap.impl.http.HomekitClientConnectionFactory;
 import com.beowulfe.hap.impl.http.HttpResponse;
+import com.beowulfe.hap.impl.jmdns.JmdnsHomekitAdvertiser;
 
 public class HomekitClientConnectionFactoryImpl implements HomekitClientConnectionFactory{
 
 	private final HomekitAuthInfo authInfo;
 	private final HomekitRegistry registry;
 	private final SubscriptionManager subscriptions;
+	private final JmdnsHomekitAdvertiser advertiser;
 
 	public HomekitClientConnectionFactoryImpl(HomekitAuthInfo authInfo,
-			HomekitRegistry registry, SubscriptionManager subscriptions) {
+			HomekitRegistry registry, SubscriptionManager subscriptions, JmdnsHomekitAdvertiser advertiser) {
 		this.registry = registry;
 		this.authInfo = authInfo;
 		this.subscriptions = subscriptions;
+		this.advertiser = advertiser;
 	}
 
 	@Override
 	public HomekitClientConnection createConnection(Consumer<HttpResponse> outOfBandMessageCallback) {
-		return new ConnectionImpl(authInfo, registry, outOfBandMessageCallback, subscriptions);
+		return new ConnectionImpl(authInfo, registry, outOfBandMessageCallback, subscriptions, advertiser);
 	}
 
 

src/main/java/com/beowulfe/hap/impl/connections/HttpSession.java

@@ -12,6 +12,7 @@
 import com.beowulfe.hap.impl.http.HomekitClientConnection;
 import com.beowulfe.hap.impl.http.HttpRequest;
 import com.beowulfe.hap.impl.http.HttpResponse;
+import com.beowulfe.hap.impl.jmdns.JmdnsHomekitAdvertiser;
 import com.beowulfe.hap.impl.json.AccessoryController;
 import com.beowulfe.hap.impl.json.CharacteristicsController;
 import com.beowulfe.hap.impl.pairing.PairVerificationManager;
@@ -31,15 +32,17 @@ class HttpSession {
 	private final HomekitRegistry registry;
 	private final SubscriptionManager subscriptions;
 	private final HomekitClientConnection connection;
+	private final JmdnsHomekitAdvertiser advertiser;
 
 	private final static Logger logger = LoggerFactory.getLogger(HttpSession.class);
 
 	public HttpSession(HomekitAuthInfo authInfo, HomekitRegistry registry, SubscriptionManager subscriptions,
-			HomekitClientConnection connection) {
+			HomekitClientConnection connection, JmdnsHomekitAdvertiser advertiser) {
 		this.authInfo = authInfo;
 		this.registry = registry;
 		this.subscriptions = subscriptions;
 		this.connection = connection;
+		this.advertiser = advertiser;
 	}
 
 	public HttpResponse handleRequest(HttpRequest request) throws IOException {
@@ -76,7 +79,7 @@ public HttpResponse handleAuthenticatedRequest(HttpRequest request) throws IOExc
 				}
 
 			case "/pairings":
-				return new PairingUpdateController(authInfo).handle(request);
+				return new PairingUpdateController(authInfo, advertiser).handle(request);
 
 			default:
 				if (request.getUri().startsWith("/characteristics?")) {
@@ -95,7 +98,7 @@ private HttpResponse handlePairSetup(HttpRequest request) {
 		if (pairingManager == null) {
 			synchronized(HttpSession.class) {
 				if (pairingManager == null) {
-					pairingManager = new PairingManager(authInfo, registry);
+					pairingManager = new PairingManager(authInfo, registry, advertiser);
 				}
 			}
 		}

src/main/java/com/beowulfe/hap/impl/jmdns/JmdnsHomekitAdvertiser.java

@@ -17,35 +17,61 @@ public class JmdnsHomekitAdvertiser {
 	private static final String SERVICE_TYPE = "_hap._tcp.local.";
 
 	private final JmDNS jmdns;
-	
+	private boolean discoverable = true;
 	private final static Logger logger = LoggerFactory.getLogger(JmdnsHomekitAdvertiser.class);
+	private boolean isAdvertising = false;
+	
+	private String label;
+	private String mac;
+	private int port;
 
 	public JmdnsHomekitAdvertiser(InetAddress localAddress) throws UnknownHostException, IOException {
 		jmdns = JmDNS.create(localAddress);
 	}
 
-	public void advertise(String label, String mac, int port) throws Exception {
+	public synchronized void advertise(String label, String mac, int port) throws Exception {
+		if (isAdvertising) {
+			throw new IllegalStateException("Homekit advertiser is already running");
+		}
+		this.label = label;
+		this.mac = mac;
+		this.port = port;
+		
 		logger.info("Advertising accessory "+label);
 
-		logger.info("Registering "+SERVICE_TYPE+" on port "+port);
-		Map<String, String> props = new HashMap<>();
-		props.put("sf", "1");
-		props.put("pv", "1.0");
-		props.put("id", mac);
-		props.put("md", label);
-		props.put("c#", "1");
-		props.put("s#", "1");
-		props.put("ff", "0");
-		jmdns.registerService(ServiceInfo.create(SERVICE_TYPE, label, port, 1, 1, props));
+		registerService();
 
 		Runtime.getRuntime().addShutdownHook(new Thread(() -> {
     		logger.info("Stopping advertising in response to shutdown.");
     		jmdns.unregisterAllServices();
     	}));
+		isAdvertising = true;
 	}
 
 	public void stop() {
 		jmdns.unregisterAllServices();
 	}
 
+	public void setDiscoverable(boolean discoverable) throws IOException {
+		this.discoverable = discoverable;
+		if (isAdvertising) {
+			logger.info("Re-creating service due to change in discoverability to "+discoverable);
+			jmdns.unregisterAllServices();
+			registerService();
+		}
+	}
+	
+	private void registerService() throws IOException {
+		logger.info("Registering "+SERVICE_TYPE+" on port "+port);
+		Map<String, String> props = new HashMap<>();
+		props.put("sf", discoverable ? "1" : "0");
+		props.put("pv", "1.0");
+		props.put("id", mac);
+		props.put("md", label);
+		props.put("c#", "1");
+		props.put("s#", "1");
+		props.put("ff", "0");
+		jmdns.registerService(ServiceInfo.create(SERVICE_TYPE, label, port, 1, 1, props));
+	}
+	
 }

src/main/java/com/beowulfe/hap/impl/pairing/FinalPairHandler.java

@@ -10,6 +10,7 @@
 import com.beowulfe.hap.impl.crypto.EdsaSigner;
 import com.beowulfe.hap.impl.crypto.EdsaVerifier;
 import com.beowulfe.hap.impl.http.HttpResponse;
+import com.beowulfe.hap.impl.jmdns.JmdnsHomekitAdvertiser;
 import com.beowulfe.hap.impl.pairing.PairSetupRequest.Stage3Request;
 import com.beowulfe.hap.impl.pairing.TypeLengthValueUtils.DecodeResult;
 import com.beowulfe.hap.impl.pairing.TypeLengthValueUtils.Encoder;
@@ -18,12 +19,14 @@ class FinalPairHandler {
 
 	private final byte[] k;
 	private final HomekitAuthInfo authInfo;
+	private final JmdnsHomekitAdvertiser advertiser;
 
 	private byte[] hkdf_enc_key;
 
-	public FinalPairHandler(byte[] k, HomekitAuthInfo authInfo) {
+	public FinalPairHandler(byte[] k, HomekitAuthInfo authInfo, JmdnsHomekitAdvertiser advertiser) {
 		this.k = k;
 		this.authInfo = authInfo;
+		this.advertiser = advertiser;
 	}
 
 	public HttpResponse handle(PairSetupRequest req) throws Exception {
@@ -60,7 +63,7 @@ private HttpResponse createUser(byte[] username, byte[] ltpk, byte[] proof) thro
 			throw new Exception("Invalid signature");
 		}
 		authInfo.createUser(authInfo.getMac()+new String(username), ltpk);
-		
+		advertiser.setDiscoverable(false);
 		return createResponse();
 	}
 

src/main/java/com/beowulfe/hap/impl/pairing/PairingManager.java

@@ -7,6 +7,7 @@
 import com.beowulfe.hap.impl.HomekitRegistry;
 import com.beowulfe.hap.impl.http.HttpRequest;
 import com.beowulfe.hap.impl.http.HttpResponse;
+import com.beowulfe.hap.impl.jmdns.JmdnsHomekitAdvertiser;
 import com.beowulfe.hap.impl.responses.NotFoundResponse;
 import com.beowulfe.hap.impl.responses.UnauthorizedResponse;
 
@@ -16,12 +17,14 @@ public class PairingManager {
 
 	private final HomekitAuthInfo authInfo;
 	private final HomekitRegistry registry;
+	private final JmdnsHomekitAdvertiser advertiser;
 
 	private SrpHandler srpHandler;
 
-	public PairingManager(HomekitAuthInfo authInfo, HomekitRegistry registry) {
+	public PairingManager(HomekitAuthInfo authInfo, HomekitRegistry registry, JmdnsHomekitAdvertiser advertiser) {
 		this.authInfo = authInfo;
 		this.registry = registry;
+		this.advertiser = advertiser;
 	}
 
 	public HttpResponse handle(HttpRequest httpRequest) throws Exception {
@@ -51,7 +54,7 @@ public HttpResponse handle(HttpRequest httpRequest) throws Exception {
 				logger.warn("Received unexpected stage 3 request for "+registry.getLabel());
 				return new UnauthorizedResponse();
 			} else {
-				FinalPairHandler handler = new FinalPairHandler(srpHandler.getK(), authInfo);
+				FinalPairHandler handler = new FinalPairHandler(srpHandler.getK(), authInfo, advertiser);
 				try {
 					return handler.handle(req);
 				} catch (Exception e) {

src/main/java/com/beowulfe/hap/impl/pairing/PairingUpdateController.java

@@ -5,14 +5,17 @@
 import com.beowulfe.hap.HomekitAuthInfo;
 import com.beowulfe.hap.impl.http.HttpRequest;
 import com.beowulfe.hap.impl.http.HttpResponse;
+import com.beowulfe.hap.impl.jmdns.JmdnsHomekitAdvertiser;
 import com.beowulfe.hap.impl.pairing.TypeLengthValueUtils.DecodeResult;
 
 public class PairingUpdateController {
 
 	private final HomekitAuthInfo authInfo;
+	private final JmdnsHomekitAdvertiser advertiser;
 
-	public PairingUpdateController(HomekitAuthInfo authInfo) {
+	public PairingUpdateController(HomekitAuthInfo authInfo, JmdnsHomekitAdvertiser advertiser) {
 		this.authInfo = authInfo;
+		this.advertiser = advertiser;
 	}
 
 	public HttpResponse handle(HttpRequest request) throws IOException {
@@ -26,6 +29,9 @@ public HttpResponse handle(HttpRequest request) throws IOException {
 		} else if (method == 4) { //Remove pairing
 			byte[] username = d.getBytes(MessageType.USERNAME);
 			authInfo.removeUser(authInfo.getMac()+new String(username));
+			if (!authInfo.hasUser()) {
+				advertiser.setDiscoverable(false);
+			}
 		} else {
 			throw new RuntimeException("Unrecognized method: "+method);
 		}