Clean up the onClatInterfaceStateUpdate() in IpClient

* Remove the unnecessary comment.
* Remove the redundant mClatInterfaceExists in IpClientLinkObserver and
  use mHasClatInterface in IpClient to handle the duplicated event.

Test: TH
Change-Id: I81794e97d6850d09847bec9a59d248b60db5bb3f

2 files changed, 4 insertions, 10 deletions

diff --git a/src/android/net/ip/IpClient.java b/src/android/net/ip/IpClient.java
index 92be9c1a..780f952b 100644
--- a/src/android/net/ip/IpClient.java
+++ b/src/android/net/ip/IpClient.java
@@ -991,10 +991,11 @@ public class IpClient extends StateMachine {
 
                     @Override
                     public void onClatInterfaceStateUpdate(boolean add) {
-                        // TODO: when clat interface was removed, consider sending a message to
-                        // the IpClient main StateMachine thread, in case "NDO enabled" state
-                        // becomes tied to more things that 464xlat operation.
                         getHandler().post(() -> {
+                            if (mHasClatInterface == add) return;
+                            // Clat interface information is spliced into LinkProperties by
+                            // ConnectivityService, so it cannot be added to the LinkProperties
+                            // here as those propagate back to ConnectivityService.
                             mCallback.setNeighborDiscoveryOffload(add ? false : true);
                             mHasClatInterface = add;
                             if (mApfFilter != null) {
diff --git a/src/android/net/ip/IpClientLinkObserver.java b/src/android/net/ip/IpClientLinkObserver.java
index 624143bd..8f2856ff 100644
--- a/src/android/net/ip/IpClientLinkObserver.java
+++ b/src/android/net/ip/IpClientLinkObserver.java
@@ -159,7 +159,6 @@ public class IpClientLinkObserver {
     private final NetworkInformationShim mShim;
     private final AlarmManager.OnAlarmListener mExpirePref64Alarm;
 
-    private boolean mClatInterfaceExists;
     private long mNat64PrefixExpiry;
 
     /**
@@ -515,17 +514,11 @@ public class IpClientLinkObserver {
     private void updateClatInterfaceLinkState(@Nullable final String ifname, short nlMsgType) {
         switch (nlMsgType) {
             case NetlinkConstants.RTM_NEWLINK:
-                if (mClatInterfaceExists) break;
-                maybeLog("clatInterfaceAdded", ifname);
                 mCallback.onClatInterfaceStateUpdate(true /* add interface */);
-                mClatInterfaceExists = true;
                 break;
 
             case NetlinkConstants.RTM_DELLINK:
-                if (!mClatInterfaceExists) break;
-                maybeLog("clatInterfaceRemoved", ifname);
                 mCallback.onClatInterfaceStateUpdate(false /* remove interface */);
-                mClatInterfaceExists = false;
                 break;
 
             default: