Optionally use MdnsAdvertiser for advertising
Based on a flag, use MdnsAdvertiser for advertising instead of the
legacy mdnsresponder implementation.
Bug: 241738458
Test: atest NsdServiceTest
Change-Id: I2d5069097c11f2959e3792cac326d179a3116479
diff --git a/service-t/src/com/android/server/NsdService.java b/service-t/src/com/android/server/NsdService.java
index 84b9f12..9510c12 100644
--- a/service-t/src/com/android/server/NsdService.java
+++ b/service-t/src/com/android/server/NsdService.java
@@ -60,6 +60,7 @@
import com.android.net.module.util.DeviceConfigUtils;
import com.android.net.module.util.PermissionUtils;
import com.android.server.connectivity.mdns.ExecutorProvider;
+import com.android.server.connectivity.mdns.MdnsAdvertiser;
import com.android.server.connectivity.mdns.MdnsDiscoveryManager;
import com.android.server.connectivity.mdns.MdnsMultinetworkSocketClient;
import com.android.server.connectivity.mdns.MdnsSearchOptions;
@@ -74,6 +75,11 @@
import java.net.NetworkInterface;
import java.net.SocketException;
import java.net.UnknownHostException;
+import java.nio.ByteBuffer;
+import java.nio.CharBuffer;
+import java.nio.charset.Charset;
+import java.nio.charset.CharsetEncoder;
+import java.nio.charset.StandardCharsets;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
@@ -89,10 +95,22 @@
public class NsdService extends INsdManager.Stub {
private static final String TAG = "NsdService";
private static final String MDNS_TAG = "mDnsConnector";
+ /**
+ * Enable discovery using the Java DiscoveryManager, instead of the legacy mdnsresponder
+ * implementation.
+ */
private static final String MDNS_DISCOVERY_MANAGER_VERSION = "mdns_discovery_manager_version";
private static final String LOCAL_DOMAIN_NAME = "local";
+ // Max label length as per RFC 1034/1035
+ private static final int MAX_LABEL_LENGTH = 63;
- private static final boolean DBG = Log.isLoggable(TAG, Log.DEBUG);
+ /**
+ * Enable advertising using the Java MdnsAdvertiser, instead of the legacy mdnsresponder
+ * implementation.
+ */
+ private static final String MDNS_ADVERTISER_VERSION = "mdns_advertiser_version";
+
+ public static final boolean DBG = Log.isLoggable(TAG, Log.DEBUG);
private static final long CLEANUP_DELAY_MS = 10000;
private static final int IFACE_IDX_ANY = 0;
@@ -106,6 +124,8 @@
private final MdnsDiscoveryManager mMdnsDiscoveryManager;
@Nullable
private final MdnsSocketProvider mMdnsSocketProvider;
+ @Nullable
+ private final MdnsAdvertiser mAdvertiser;
// WARNING : Accessing these values in any thread is not safe, it must only be changed in the
// state machine thread. If change this outside state machine, it will need to introduce
// synchronization.
@@ -345,7 +365,7 @@
mLegacyClientCount -= 1;
}
}
- if (mMdnsDiscoveryManager != null) {
+ if (mMdnsDiscoveryManager != null || mAdvertiser != null) {
maybeStopMonitoringSocketsIfNoActiveRequest();
}
maybeScheduleStop();
@@ -446,6 +466,7 @@
clientInfo.mClientRequests.delete(clientId);
mIdToClientInfoMap.remove(globalId);
maybeScheduleStop();
+ maybeStopMonitoringSocketsIfNoActiveRequest();
}
private void storeListenerMap(int clientId, int transactionId, MdnsListener listener,
@@ -484,8 +505,31 @@
final Matcher matcher = serviceTypePattern.matcher(serviceType);
if (!matcher.matches()) return null;
return matcher.group(1) == null
- ? serviceType + ".local"
- : matcher.group(1) + "_sub." + matcher.group(2) + ".local";
+ ? serviceType
+ : matcher.group(1) + "_sub." + matcher.group(2);
+ }
+
+ /**
+ * Truncate a service name to up to 63 UTF-8 bytes.
+ *
+ * See RFC6763 4.1.1: service instance names are UTF-8 and up to 63 bytes. Truncating
+ * names used in registerService follows historical behavior (see mdnsresponder
+ * handle_regservice_request).
+ */
+ @NonNull
+ private String truncateServiceName(@NonNull String originalName) {
+ // UTF-8 is at most 4 bytes per character; return early in the common case where
+ // the name can't possibly be over the limit given its string length.
+ if (originalName.length() <= MAX_LABEL_LENGTH / 4) return originalName;
+
+ final Charset utf8 = StandardCharsets.UTF_8;
+ final CharsetEncoder encoder = utf8.newEncoder();
+ final ByteBuffer out = ByteBuffer.allocate(MAX_LABEL_LENGTH);
+ // encode will write as many characters as possible to the out buffer, and just
+ // return an overflow code if there were too many characters (no need to check the
+ // return code here, this method truncates the name on purpose).
+ encoder.encode(CharBuffer.wrap(originalName), out, true /* endOfInput */);
+ return new String(out.array(), 0, out.position(), utf8);
}
@Override
@@ -523,14 +567,16 @@
break;
}
+ final String listenServiceType = serviceType + ".local";
maybeStartMonitoringSockets();
final MdnsListener listener =
- new DiscoveryListener(clientId, id, info, serviceType);
+ new DiscoveryListener(clientId, id, info, listenServiceType);
final MdnsSearchOptions options = MdnsSearchOptions.newBuilder()
.setNetwork(info.getNetwork())
.setIsPassiveMode(true)
.build();
- mMdnsDiscoveryManager.registerListener(serviceType, listener, options);
+ mMdnsDiscoveryManager.registerListener(
+ listenServiceType, listener, options);
storeListenerMap(clientId, id, listener, clientInfo);
clientInfo.onDiscoverServicesStarted(clientId, info);
} else {
@@ -608,16 +654,36 @@
break;
}
- maybeStartDaemon();
id = getUniqueId();
- if (registerService(id, args.serviceInfo)) {
- if (DBG) Log.d(TAG, "Register " + clientId + " " + id);
+ if (mAdvertiser != null) {
+ final NsdServiceInfo serviceInfo = args.serviceInfo;
+ final String serviceType = serviceInfo.getServiceType();
+ final String registerServiceType = constructServiceType(serviceType);
+ if (registerServiceType == null) {
+ Log.e(TAG, "Invalid service type: " + serviceType);
+ clientInfo.onRegisterServiceFailed(clientId,
+ NsdManager.FAILURE_INTERNAL_ERROR);
+ break;
+ }
+ serviceInfo.setServiceType(registerServiceType);
+ serviceInfo.setServiceName(truncateServiceName(
+ serviceInfo.getServiceName()));
+
+ maybeStartMonitoringSockets();
+ mAdvertiser.addService(id, serviceInfo);
storeRequestMap(clientId, id, clientInfo, msg.what);
- // Return success after mDns reports success
} else {
- unregisterService(id);
- clientInfo.onRegisterServiceFailed(
- clientId, NsdManager.FAILURE_INTERNAL_ERROR);
+ maybeStartDaemon();
+ if (registerService(id, args.serviceInfo)) {
+ if (DBG) Log.d(TAG, "Register " + clientId + " " + id);
+ storeRequestMap(clientId, id, clientInfo, msg.what);
+ // Return success after mDns reports success
+ } else {
+ unregisterService(id);
+ clientInfo.onRegisterServiceFailed(
+ clientId, NsdManager.FAILURE_INTERNAL_ERROR);
+ }
+
}
break;
case NsdManager.UNREGISTER_SERVICE:
@@ -633,11 +699,17 @@
}
id = clientInfo.mClientIds.get(clientId);
removeRequestMap(clientId, id, clientInfo);
- if (unregisterService(id)) {
+
+ if (mAdvertiser != null) {
+ mAdvertiser.removeService(id);
clientInfo.onUnregisterServiceSucceeded(clientId);
} else {
- clientInfo.onUnregisterServiceFailed(
- clientId, NsdManager.FAILURE_INTERNAL_ERROR);
+ if (unregisterService(id)) {
+ clientInfo.onUnregisterServiceSucceeded(clientId);
+ } else {
+ clientInfo.onUnregisterServiceFailed(
+ clientId, NsdManager.FAILURE_INTERNAL_ERROR);
+ }
}
break;
case NsdManager.RESOLVE_SERVICE: {
@@ -661,15 +733,17 @@
NsdManager.FAILURE_INTERNAL_ERROR);
break;
}
+ final String resolveServiceType = serviceType + ".local";
maybeStartMonitoringSockets();
final MdnsListener listener =
- new ResolutionListener(clientId, id, info, serviceType);
+ new ResolutionListener(clientId, id, info, resolveServiceType);
final MdnsSearchOptions options = MdnsSearchOptions.newBuilder()
.setNetwork(info.getNetwork())
.setIsPassiveMode(true)
.build();
- mMdnsDiscoveryManager.registerListener(serviceType, listener, options);
+ mMdnsDiscoveryManager.registerListener(
+ resolveServiceType, listener, options);
storeListenerMap(clientId, id, listener, clientInfo);
} else {
if (clientInfo.mResolvedService != null) {
@@ -1005,18 +1079,32 @@
mNsdStateMachine.start();
mMDnsManager = ctx.getSystemService(MDnsManager.class);
mMDnsEventCallback = new MDnsEventCallback(mNsdStateMachine);
- if (deps.isMdnsDiscoveryManagerEnabled(ctx)) {
+
+ final boolean discoveryManagerEnabled = deps.isMdnsDiscoveryManagerEnabled(ctx);
+ final boolean advertiserEnabled = deps.isMdnsAdvertiserEnabled(ctx);
+ if (discoveryManagerEnabled || advertiserEnabled) {
mMdnsSocketProvider = deps.makeMdnsSocketProvider(ctx, handler.getLooper());
+ } else {
+ mMdnsSocketProvider = null;
+ }
+
+ if (discoveryManagerEnabled) {
mMdnsSocketClient =
new MdnsMultinetworkSocketClient(handler.getLooper(), mMdnsSocketProvider);
mMdnsDiscoveryManager =
deps.makeMdnsDiscoveryManager(new ExecutorProvider(), mMdnsSocketClient);
handler.post(() -> mMdnsSocketClient.setCallback(mMdnsDiscoveryManager));
} else {
- mMdnsSocketProvider = null;
mMdnsSocketClient = null;
mMdnsDiscoveryManager = null;
}
+
+ if (advertiserEnabled) {
+ mAdvertiser = deps.makeMdnsAdvertiser(handler.getLooper(), mMdnsSocketProvider,
+ new AdvertiserCallback());
+ } else {
+ mAdvertiser = null;
+ }
}
/**
@@ -1025,10 +1113,10 @@
@VisibleForTesting
public static class Dependencies {
/**
- * Check whether or not MdnsDiscoveryManager feature is enabled.
+ * Check whether the MdnsDiscoveryManager feature is enabled.
*
* @param context The global context information about an app environment.
- * @return true if MdnsDiscoveryManager feature is enabled.
+ * @return true if the MdnsDiscoveryManager feature is enabled.
*/
public boolean isMdnsDiscoveryManagerEnabled(Context context) {
return DeviceConfigUtils.isFeatureEnabled(context, NAMESPACE_CONNECTIVITY,
@@ -1036,6 +1124,17 @@
}
/**
+ * Check whether the MdnsAdvertiser feature is enabled.
+ *
+ * @param context The global context information about an app environment.
+ * @return true if the MdnsAdvertiser feature is enabled.
+ */
+ public boolean isMdnsAdvertiserEnabled(Context context) {
+ return DeviceConfigUtils.isFeatureEnabled(context, NAMESPACE_CONNECTIVITY,
+ MDNS_ADVERTISER_VERSION, false /* defaultEnabled */);
+ }
+
+ /**
* @see MdnsDiscoveryManager
*/
public MdnsDiscoveryManager makeMdnsDiscoveryManager(
@@ -1044,6 +1143,15 @@
}
/**
+ * @see MdnsAdvertiser
+ */
+ public MdnsAdvertiser makeMdnsAdvertiser(
+ @NonNull Looper looper, @NonNull MdnsSocketProvider socketProvider,
+ @NonNull MdnsAdvertiser.AdvertiserCallback cb) {
+ return new MdnsAdvertiser(looper, socketProvider, cb);
+ }
+
+ /**
* @see MdnsSocketProvider
*/
public MdnsSocketProvider makeMdnsSocketProvider(Context context, Looper looper) {
@@ -1101,6 +1209,49 @@
}
}
+ private class AdvertiserCallback implements MdnsAdvertiser.AdvertiserCallback {
+ @Override
+ public void onRegisterServiceSucceeded(int serviceId, NsdServiceInfo registeredInfo) {
+ final ClientInfo clientInfo = getClientInfoOrLog(serviceId);
+ if (clientInfo == null) return;
+
+ final int clientId = getClientIdOrLog(clientInfo, serviceId);
+ if (clientId < 0) return;
+
+ // onRegisterServiceSucceeded only has the service name in its info. This aligns with
+ // historical behavior.
+ final NsdServiceInfo cbInfo = new NsdServiceInfo(registeredInfo.getServiceName(), null);
+ clientInfo.onRegisterServiceSucceeded(clientId, cbInfo);
+ }
+
+ @Override
+ public void onRegisterServiceFailed(int serviceId, int errorCode) {
+ final ClientInfo clientInfo = getClientInfoOrLog(serviceId);
+ if (clientInfo == null) return;
+
+ final int clientId = getClientIdOrLog(clientInfo, serviceId);
+ if (clientId < 0) return;
+
+ clientInfo.onRegisterServiceFailed(clientId, errorCode);
+ }
+
+ private ClientInfo getClientInfoOrLog(int serviceId) {
+ final ClientInfo clientInfo = mIdToClientInfoMap.get(serviceId);
+ if (clientInfo == null) {
+ Log.e(TAG, String.format("Callback for service %d has no client", serviceId));
+ }
+ return clientInfo;
+ }
+
+ private int getClientIdOrLog(@NonNull ClientInfo info, int serviceId) {
+ final int clientId = info.getClientId(serviceId);
+ if (clientId < 0) {
+ Log.e(TAG, String.format("Client ID not found for service %d", serviceId));
+ }
+ return clientId;
+ }
+ }
+
@Override
public INsdServiceConnector connect(INsdManagerCallback cb) {
mContext.enforceCallingOrSelfPermission(android.Manifest.permission.INTERNET, "NsdService");
@@ -1364,7 +1515,11 @@
stopResolveService(globalId);
break;
case NsdManager.REGISTER_SERVICE:
- unregisterService(globalId);
+ if (mAdvertiser != null) {
+ mAdvertiser.removeService(globalId);
+ } else {
+ unregisterService(globalId);
+ }
break;
default:
break;