Fix watchdog to stop ping after wifi disconnects

- The pings are delayed async messages that were getting handled
after a disconnect as well

- Increase poll time to 200 ms, so we block on a receive for 1ms every 200ms for a
sent packet

Bug: 5361564
Change-Id: I1931a1c4146e78a87407d541d8c3934ff8232604

Author: isheriff

core/java/android/net/DnsPinger.java

@@ -53,7 +53,7 @@
 public final class DnsPinger extends Handler {
     private static final boolean V = true;
 
-    private static final int RECEIVE_POLL_INTERVAL_MS = 30;
+    private static final int RECEIVE_POLL_INTERVAL_MS = 200;
     private static final int DNS_PORT = 53;
 
     /** Short socket timeout so we don't block one any 'receive' call */
@@ -70,6 +70,9 @@ public final class DnsPinger extends Handler {
     private final ArrayList<InetAddress> mDefaultDns;
     private String TAG;
 
+    //Invalidates old dns requests upon a cancel
+    private AtomicInteger mCurrentToken = new AtomicInteger();
+
     private static final int BASE = Protocol.BASE_DNS_PINGER;
 
     /**
@@ -102,6 +105,17 @@ private class ActivePing {
         long start = SystemClock.elapsedRealtime();
     }
 
+    /* Message argument for ACTION_PING_DNS */
+    private class DnsArg {
+        InetAddress dns;
+        int seq;
+
+        DnsArg(InetAddress d, int s) {
+            dns = d;
+            seq = s;
+        }
+    }
+
     public DnsPinger(Context context, String TAG, Looper looper,
             Handler target, int connectionType) {
         super(looper);
@@ -122,9 +136,13 @@ public DnsPinger(Context context, String TAG, Looper looper,
     public void handleMessage(Message msg) {
         switch (msg.what) {
             case ACTION_PING_DNS:
+                DnsArg dnsArg = (DnsArg) msg.obj;
+                if (dnsArg.seq != mCurrentToken.get()) {
+                    break;
+                }
                 try {
                     ActivePing newActivePing = new ActivePing();
-                    InetAddress dnsAddress = (InetAddress) msg.obj;
+                    InetAddress dnsAddress = dnsArg.dns;
                     newActivePing.internalId = msg.arg1;
                     newActivePing.timeout = msg.arg2;
                     newActivePing.socket = new DatagramSocket();
@@ -248,11 +266,13 @@ public List<InetAddress> getDnsList() {
      */
     public int pingDnsAsync(InetAddress dns, int timeout, int delay) {
         int id = sCounter.incrementAndGet();
-        sendMessageDelayed(obtainMessage(ACTION_PING_DNS, id, timeout, dns), delay);
+        sendMessageDelayed(obtainMessage(ACTION_PING_DNS, id, timeout,
+                new DnsArg(dns, mCurrentToken.get())), delay);
         return id;
     }
 
     public void cancelPings() {
+        mCurrentToken.incrementAndGet();
         obtainMessage(ACTION_CANCEL_ALL_PINGS).sendToTarget();
     }
 

wifi/java/android/net/wifi/WifiWatchdogStateMachine.java

@@ -589,12 +589,11 @@ public boolean processMessage(Message msg) {
                             updateBssids();
                             transitionTo(mDnsCheckingState);
                             mNetEventCounter++;
-                            return HANDLED;
-                        case DISCONNECTED:
-                        case DISCONNECTING:
+                            break;
+                        default:
                             mNetEventCounter++;
                             transitionTo(mNotConnectedState);
-                            return HANDLED;
+                            break;
                     }
                     return HANDLED;
                 case EVENT_WIFI_RADIO_STATE_CHANGE: