Make NsdService only start the native daemon when needed and automatically clean it up.
Currently, NsdService starts the native mdnsresponder daemon if any
NsdManager connect to it, which results in that when any constant
service holds the NsdManager connection, the device would always be
in the mdns multicast group whatever the connection is not used or not.
This is because mdnsresponder will join the multicast group when it
starts.
To solve this problem, start the native daemon only when needed, and
clean it up after the given idle timeout.
1. Start the native daemon when a new request come.
2. If there is no pending request, clean up the daemon after 3 seconds
of idle time.
Bug: 181810560
Test: atest NsdManagerTest NsdServiceTest
Original-Change: https://android-review.googlesource.com/1717479
Merged-In: I3eb04552f6cf6c0c68c07abffe751bb4d0669215
Change-Id: I3eb04552f6cf6c0c68c07abffe751bb4d0669215
diff --git a/core/java/android/net/nsd/NsdManager.java b/core/java/android/net/nsd/NsdManager.java
index 64f20b8..5a25cfc 100644
--- a/core/java/android/net/nsd/NsdManager.java
+++ b/core/java/android/net/nsd/NsdManager.java
@@ -200,6 +200,9 @@
public static final int RESOLVE_SERVICE_SUCCEEDED = BASE + 20;
/** @hide */
+ public static final int DAEMON_CLEANUP = BASE + 21;
+
+ /** @hide */
public static final int ENABLE = BASE + 24;
/** @hide */
public static final int DISABLE = BASE + 25;
diff --git a/services/core/java/com/android/server/NsdService.java b/services/core/java/com/android/server/NsdService.java
index 84f40cb..a481a6a 100644
--- a/services/core/java/com/android/server/NsdService.java
+++ b/services/core/java/com/android/server/NsdService.java
@@ -61,6 +61,7 @@
private static final String MDNS_TAG = "mDnsConnector";
private static final boolean DBG = true;
+ private static final long CLEANUP_DELAY_MS = 3000;
private final Context mContext;
private final NsdSettings mNsdSettings;
@@ -77,6 +78,7 @@
private final SparseArray<ClientInfo> mIdToClientInfoMap= new SparseArray<>();
private final AsyncChannel mReplyChannel = new AsyncChannel();
+ private final long mCleanupDelayMs;
private static final int INVALID_ID = 0;
private int mUniqueId = 1;
@@ -92,6 +94,22 @@
return NsdManager.nameOf(what);
}
+ void maybeStartDaemon() {
+ mDaemon.maybeStart();
+ maybeScheduleStop();
+ }
+
+ void maybeScheduleStop() {
+ if (!isAnyRequestActive()) {
+ cancelStop();
+ sendMessageDelayed(NsdManager.DAEMON_CLEANUP, mCleanupDelayMs);
+ }
+ }
+
+ void cancelStop() {
+ this.removeMessages(NsdManager.DAEMON_CLEANUP);
+ }
+
/**
* Observes the NSD on/off setting, and takes action when changed.
*/
@@ -151,10 +169,6 @@
cInfo.expungeAllRequests();
mClients.remove(msg.replyTo);
}
- //Last client
- if (mClients.size() == 0) {
- mDaemon.stop();
- }
break;
case AsyncChannel.CMD_CHANNEL_FULL_CONNECTION:
AsyncChannel ac = new AsyncChannel();
@@ -180,6 +194,9 @@
replyToMessage(msg, NsdManager.RESOLVE_SERVICE_FAILED,
NsdManager.FAILURE_INTERNAL_ERROR);
break;
+ case NsdManager.DAEMON_CLEANUP:
+ mDaemon.maybeStop();
+ break;
case NsdManager.NATIVE_DAEMON_EVENT:
default:
Slog.e(TAG, "Unhandled " + msg);
@@ -212,16 +229,13 @@
@Override
public void enter() {
sendNsdStateChangeBroadcast(true);
- if (mClients.size() > 0) {
- mDaemon.start();
- }
}
@Override
public void exit() {
- if (mClients.size() > 0) {
- mDaemon.stop();
- }
+ // TODO: it is incorrect to stop the daemon without expunging all requests
+ // and sending error callbacks to clients.
+ maybeScheduleStop();
}
private boolean requestLimitReached(ClientInfo clientInfo) {
@@ -236,12 +250,15 @@
clientInfo.mClientIds.put(clientId, globalId);
clientInfo.mClientRequests.put(clientId, what);
mIdToClientInfoMap.put(globalId, clientInfo);
+ // Remove the cleanup event because here comes a new request.
+ cancelStop();
}
private void removeRequestMap(int clientId, int globalId, ClientInfo clientInfo) {
clientInfo.mClientIds.delete(clientId);
clientInfo.mClientRequests.delete(clientId);
mIdToClientInfoMap.remove(globalId);
+ maybeScheduleStop();
}
@Override
@@ -251,14 +268,12 @@
int id;
switch (msg.what) {
case AsyncChannel.CMD_CHANNEL_HALF_CONNECTED:
- //First client
- if (msg.arg1 == AsyncChannel.STATUS_SUCCESSFUL &&
- mClients.size() == 0) {
- mDaemon.start();
- }
return NOT_HANDLED;
case AsyncChannel.CMD_CHANNEL_DISCONNECTED:
return NOT_HANDLED;
+ }
+
+ switch (msg.what) {
case NsdManager.DISABLE:
//TODO: cleanup clients
transitionTo(mDisabledState);
@@ -274,6 +289,7 @@
break;
}
+ maybeStartDaemon();
id = getUniqueId();
if (discoverServices(id, servInfo.getServiceType())) {
if (DBG) {
@@ -316,6 +332,7 @@
break;
}
+ maybeStartDaemon();
id = getUniqueId();
if (registerService(id, (NsdServiceInfo) msg.obj)) {
if (DBG) Slog.d(TAG, "Register " + msg.arg2 + " " + id);
@@ -357,6 +374,7 @@
break;
}
+ maybeStartDaemon();
id = getUniqueId();
if (resolveService(id, servInfo)) {
clientInfo.mResolvedService = new NsdServiceInfo();
@@ -513,6 +531,10 @@
}
}
+ private boolean isAnyRequestActive() {
+ return mIdToClientInfoMap.size() != 0;
+ }
+
private String unescape(String s) {
StringBuilder sb = new StringBuilder(s.length());
for (int i = 0; i < s.length(); ++i) {
@@ -538,7 +560,9 @@
}
@VisibleForTesting
- NsdService(Context ctx, NsdSettings settings, Handler handler, DaemonConnectionSupplier fn) {
+ NsdService(Context ctx, NsdSettings settings, Handler handler,
+ DaemonConnectionSupplier fn, long cleanupDelayMs) {
+ mCleanupDelayMs = cleanupDelayMs;
mContext = ctx;
mNsdSettings = settings;
mNsdStateMachine = new NsdStateMachine(TAG, handler);
@@ -552,7 +576,8 @@
HandlerThread thread = new HandlerThread(TAG);
thread.start();
Handler handler = new Handler(thread.getLooper());
- NsdService service = new NsdService(context, settings, handler, DaemonConnection::new);
+ NsdService service = new NsdService(context, settings, handler,
+ DaemonConnection::new, CLEANUP_DELAY_MS);
service.mDaemonCallback.awaitConnection();
return service;
}
@@ -681,12 +706,16 @@
@VisibleForTesting
public static class DaemonConnection {
final NativeDaemonConnector mNativeConnector;
+ boolean mIsStarted = false;
DaemonConnection(NativeCallbackReceiver callback) {
mNativeConnector = new NativeDaemonConnector(callback, "mdns", 10, MDNS_TAG, 25, null);
new Thread(mNativeConnector, MDNS_TAG).start();
}
+ /**
+ * Executes the specified cmd on the daemon.
+ */
public boolean execute(Object... args) {
if (DBG) {
Slog.d(TAG, "mdnssd " + Arrays.toString(args));
@@ -700,12 +729,26 @@
return true;
}
- public void start() {
+ /**
+ * Starts the daemon if it is not already started.
+ */
+ public void maybeStart() {
+ if (mIsStarted) {
+ return;
+ }
execute("start-service");
+ mIsStarted = true;
}
- public void stop() {
+ /**
+ * Stops the daemon if it is started.
+ */
+ public void maybeStop() {
+ if (!mIsStarted) {
+ return;
+ }
execute("stop-service");
+ mIsStarted = false;
}
}
@@ -864,6 +907,7 @@
}
mClientIds.clear();
mClientRequests.clear();
+ mNsdStateMachine.maybeScheduleStop();
}
// mClientIds is a sparse array of listener id -> mDnsClient id. For a given mDnsClient id,
