Merge "Notify NetworkStats only when interfaces changed in updateLinkProperties"
diff --git a/service/src/com/android/server/ConnectivityService.java b/service/src/com/android/server/ConnectivityService.java
index 195f046..6ef239d 100755
--- a/service/src/com/android/server/ConnectivityService.java
+++ b/service/src/com/android/server/ConnectivityService.java
@@ -7500,7 +7500,7 @@
     }
 
     private void updateLinkProperties(NetworkAgentInfo networkAgent, @NonNull LinkProperties newLp,
-            @NonNull LinkProperties oldLp) {
+            @Nullable LinkProperties oldLp) {
         int netId = networkAgent.network.getNetId();
 
         // The NetworkAgent does not know whether clatd is running on its network or not, or whether
@@ -7552,7 +7552,13 @@
             }
             // Start or stop DNS64 detection and 464xlat according to network state.
             networkAgent.clatd.update();
-            notifyIfacesChangedForNetworkStats();
+            // Notify NSS when relevant events happened. Currently, NSS only cares about
+            // interface changed to update clat interfaces accounting.
+            final boolean interfacesChanged = oldLp == null
+                    || !Objects.equals(newLp.getAllInterfaceNames(), oldLp.getAllInterfaceNames());
+            if (interfacesChanged) {
+                notifyIfacesChangedForNetworkStats();
+            }
             networkAgent.networkMonitor().notifyLinkPropertiesChanged(
                     new LinkProperties(newLp, true /* parcelSensitiveFields */));
             notifyNetworkCallbacks(networkAgent, ConnectivityManager.CALLBACK_IP_CHANGED);
@@ -8315,7 +8321,8 @@
         }
     }
 
-    public void handleUpdateLinkProperties(NetworkAgentInfo nai, LinkProperties newLp) {
+    public void handleUpdateLinkProperties(@NonNull NetworkAgentInfo nai,
+            @NonNull LinkProperties newLp) {
         ensureRunningOnConnectivityServiceThread();
 
         if (!mNetworkAgentInfos.contains(nai)) {
diff --git a/service/src/com/android/server/connectivity/Nat464Xlat.java b/service/src/com/android/server/connectivity/Nat464Xlat.java
index 4e19781..2ac2ad3 100644
--- a/service/src/com/android/server/connectivity/Nat464Xlat.java
+++ b/service/src/com/android/server/connectivity/Nat464Xlat.java
@@ -22,6 +22,7 @@
 import static com.android.net.module.util.CollectionUtils.contains;
 
 import android.annotation.NonNull;
+import android.annotation.Nullable;
 import android.net.ConnectivityManager;
 import android.net.IDnsResolver;
 import android.net.INetd;
@@ -420,7 +421,7 @@
      * This is necessary because the LinkProperties in mNetwork come from the transport layer, which
      * has no idea that 464xlat is running on top of it.
      */
-    public void fixupLinkProperties(@NonNull LinkProperties oldLp, @NonNull LinkProperties lp) {
+    public void fixupLinkProperties(@Nullable LinkProperties oldLp, @NonNull LinkProperties lp) {
         // This must be done even if clatd is not running, because otherwise shouldStartClat would
         // never return true.
         lp.setNat64Prefix(selectNat64Prefix());
@@ -433,6 +434,8 @@
         }
 
         Log.d(TAG, "clatd running, updating NAI for " + mIface);
+        // oldLp can't be null here since shouldStartClat checks null LinkProperties to start clat.
+        // Thus, the status won't pass isRunning check if the oldLp is null.
         for (LinkProperties stacked: oldLp.getStackedLinks()) {
             if (Objects.equals(mIface, stacked.getInterfaceName())) {
                 lp.addStackedLink(stacked);
diff --git a/tests/unit/java/com/android/server/ConnectivityServiceTest.java b/tests/unit/java/com/android/server/ConnectivityServiceTest.java
index 2d8cf80..65e0b10 100755
--- a/tests/unit/java/com/android/server/ConnectivityServiceTest.java
+++ b/tests/unit/java/com/android/server/ConnectivityServiceTest.java
@@ -7236,6 +7236,15 @@
         expectNotifyNetworkStatus(onlyCell(), onlyCell(), MOBILE_IFNAME);
         reset(mStatsManager);
 
+        // Verify change fields other than interfaces does not trigger a notification to NSS.
+        cellLp.addLinkAddress(new LinkAddress("192.0.2.4/24"));
+        cellLp.addRoute(new RouteInfo((IpPrefix) null, InetAddress.getByName("192.0.2.4"),
+                MOBILE_IFNAME));
+        cellLp.setDnsServers(List.of(InetAddress.getAllByName("8.8.8.8")));
+        mCellNetworkAgent.sendLinkProperties(cellLp);
+        verifyNoMoreInteractions(mStatsManager);
+        reset(mStatsManager);
+
         // Default network switch should update ifaces.
         mWiFiNetworkAgent.connect(false);
         mWiFiNetworkAgent.sendLinkProperties(wifiLp);