Keep the native mdns daemon alive for pre-S application
Roll back the behavior changes by checking the target SDK to ensure that
there are no compatibility issues with the pre-S application.
If the target SDK of the application <S, NsdManager will actively send a
cmd to start the native daemon, and NsdService will keep the daemon
until the last client with the target SDK <S disconnects.
Test: atest NsdManagerTest NsdServiceTest
Bug: 191844585
Change-Id: Ie93d5d585e126fe220ae865bbc7274f21a925984
diff --git a/core/java/android/net/nsd/NsdManager.java b/core/java/android/net/nsd/NsdManager.java
index 5a25cfc..ae8d010 100644
--- a/core/java/android/net/nsd/NsdManager.java
+++ b/core/java/android/net/nsd/NsdManager.java
@@ -23,6 +23,9 @@
import android.annotation.SdkConstant;
import android.annotation.SdkConstant.SdkConstantType;
import android.annotation.SystemService;
+import android.app.compat.CompatChanges;
+import android.compat.annotation.ChangeId;
+import android.compat.annotation.EnabledSince;
import android.content.Context;
import android.os.Handler;
import android.os.HandlerThread;
@@ -126,6 +129,24 @@
private static final boolean DBG = false;
/**
+ * When enabled, apps targeting < Android 12 are considered legacy for
+ * the NSD native daemon.
+ * The platform will only keep the daemon running as long as there are
+ * any legacy apps connected.
+ *
+ * After Android 12, directly communicate with native daemon might not
+ * work since the native damon won't always stay alive.
+ * Use the NSD APIs from NsdManager as the replacement is recommended.
+ * An another alternative could be bundling your own mdns solutions instead of
+ * depending on the system mdns native daemon.
+ *
+ * @hide
+ */
+ @ChangeId
+ @EnabledSince(targetSdkVersion = android.os.Build.VERSION_CODES.S)
+ public static final long RUN_NATIVE_NSD_ONLY_IF_LEGACY_APPS = 191844585L;
+
+ /**
* Broadcast intent action to indicate whether network service discovery is
* enabled or disabled. An extra {@link #EXTRA_NSD_STATE} provides the state
* information as int.
@@ -203,6 +224,9 @@
public static final int DAEMON_CLEANUP = BASE + 21;
/** @hide */
+ public static final int DAEMON_STARTUP = BASE + 22;
+
+ /** @hide */
public static final int ENABLE = BASE + 24;
/** @hide */
public static final int DISABLE = BASE + 25;
@@ -232,6 +256,8 @@
EVENT_NAMES.put(RESOLVE_SERVICE, "RESOLVE_SERVICE");
EVENT_NAMES.put(RESOLVE_SERVICE_FAILED, "RESOLVE_SERVICE_FAILED");
EVENT_NAMES.put(RESOLVE_SERVICE_SUCCEEDED, "RESOLVE_SERVICE_SUCCEEDED");
+ EVENT_NAMES.put(DAEMON_CLEANUP, "DAEMON_CLEANUP");
+ EVENT_NAMES.put(DAEMON_STARTUP, "DAEMON_STARTUP");
EVENT_NAMES.put(ENABLE, "ENABLE");
EVENT_NAMES.put(DISABLE, "DISABLE");
EVENT_NAMES.put(NATIVE_DAEMON_EVENT, "NATIVE_DAEMON_EVENT");
@@ -494,6 +520,12 @@
} catch (InterruptedException e) {
fatal("Interrupted wait at init");
}
+ if (CompatChanges.isChangeEnabled(RUN_NATIVE_NSD_ONLY_IF_LEGACY_APPS)) {
+ return;
+ }
+ // Only proactively start the daemon if the target SDK < S, otherwise the internal service
+ // would automatically start/stop the native daemon as needed.
+ mAsyncChannel.sendMessage(DAEMON_STARTUP);
}
private static void fatal(String msg) {
diff --git a/services/core/java/com/android/server/NsdService.java b/services/core/java/com/android/server/NsdService.java
index a9f3a1b..462ed5c 100644
--- a/services/core/java/com/android/server/NsdService.java
+++ b/services/core/java/com/android/server/NsdService.java
@@ -82,6 +82,8 @@
private static final int INVALID_ID = 0;
private int mUniqueId = 1;
+ // The count of the connected legacy clients.
+ private int mLegacyClientCount = 0;
private class NsdStateMachine extends StateMachine {
@@ -107,7 +109,9 @@
sendMessageDelayed(NsdManager.DAEMON_CLEANUP, mCleanupDelayMs);
}
private void maybeScheduleStop() {
- if (!isAnyRequestActive()) {
+ // The native daemon should stay alive and can't be cleanup
+ // if any legacy client connected.
+ if (!isAnyRequestActive() && mLegacyClientCount == 0) {
scheduleStop();
}
}
@@ -175,11 +179,11 @@
if (cInfo != null) {
cInfo.expungeAllRequests();
mClients.remove(msg.replyTo);
+ if (cInfo.isLegacy()) {
+ mLegacyClientCount -= 1;
+ }
}
- //Last client
- if (mClients.size() == 0) {
- scheduleStop();
- }
+ maybeScheduleStop();
break;
case AsyncChannel.CMD_CHANNEL_FULL_CONNECTION:
AsyncChannel ac = new AsyncChannel();
@@ -208,6 +212,17 @@
case NsdManager.DAEMON_CLEANUP:
mDaemon.maybeStop();
break;
+ // This event should be only sent by the legacy (target SDK < S) clients.
+ // Mark the sending client as legacy.
+ case NsdManager.DAEMON_STARTUP:
+ cInfo = mClients.get(msg.replyTo);
+ if (cInfo != null) {
+ cancelStop();
+ cInfo.setLegacy();
+ mLegacyClientCount += 1;
+ maybeStartDaemon();
+ }
+ break;
case NsdManager.NATIVE_DAEMON_EVENT:
default:
Slog.e(TAG, "Unhandled " + msg);
@@ -863,6 +878,9 @@
/* A map from client id to the type of the request we had received */
private final SparseIntArray mClientRequests = new SparseIntArray();
+ // The target SDK of this client < Build.VERSION_CODES.S
+ private boolean mIsLegacy = false;
+
private ClientInfo(AsyncChannel c, Messenger m) {
mChannel = c;
mMessenger = m;
@@ -875,6 +893,7 @@
sb.append("mChannel ").append(mChannel).append("\n");
sb.append("mMessenger ").append(mMessenger).append("\n");
sb.append("mResolvedService ").append(mResolvedService).append("\n");
+ sb.append("mIsLegacy ").append(mIsLegacy).append("\n");
for(int i = 0; i< mClientIds.size(); i++) {
int clientID = mClientIds.keyAt(i);
sb.append("clientId ").append(clientID).
@@ -884,6 +903,14 @@
return sb.toString();
}
+ private boolean isLegacy() {
+ return mIsLegacy;
+ }
+
+ private void setLegacy() {
+ mIsLegacy = true;
+ }
+
// Remove any pending requests from the global map when we get rid of a client,
// and send cancellations to the daemon.
private void expungeAllRequests() {