Delay connectivity change notifications.

Because changes to the route tables take time to propagate
we add a delay when sending out change notifications. This allows
applications, such as GTalk, to create sockets without encountering
a 3 minute timeout.

Bug: 5008488
Change-Id: I0eefb03a5d6358a58ea6ae5b4f697ff302b5511d

Author: Wink Saville

core/java/android/provider/Settings.java

@@ -3022,6 +3022,18 @@ public static final String getBluetoothInputDevicePriorityKey(String address) {
          */
         public static final String TTY_MODE_ENABLED = "tty_mode_enabled";
 
+        /**
+         * The number of milliseconds to delay before sending out Connectivyt Change broadcasts
+         * @hide
+         */
+        public static final String CONNECTIVITY_CHANGE_DELAY = "connectivity_change_delay";
+
+        /**
+         * Default value for CONNECTIVITY_CHANGE_DELAY in milliseconds.
+         * @hide
+         */
+        public static final int CONNECTIVITY_CHANGE_DELAY_DEFAULT = 3000;
+
         /**
          * Controls whether settings backup is enabled.
          * Type: int ( 0 = disabled, 1 = enabled )

services/java/com/android/server/ConnectivityService.java

@@ -216,6 +216,12 @@ public class ConnectivityService extends IConnectivityManager.Stub {
     private static final int EVENT_SET_DEPENDENCY_MET =
             MAX_NETWORK_STATE_TRACKER_EVENT + 10;
 
+    /**
+     * used internally to send a sticky broadcast delayed.
+     */
+    private static final int EVENT_SEND_STICKY_BROADCAST_INTENT =
+            MAX_NETWORK_STATE_TRACKER_EVENT + 11;
+
     private Handler mHandler;
 
     // list of DeathRecipients used to make sure features are turned off when
@@ -511,6 +517,17 @@ private void handleSetNetworkPreference(int preference) {
         }
     }
 
+    private int getConnectivityChangeDelay() {
+        final ContentResolver cr = mContext.getContentResolver();
+
+        /** Check system properties for the default value then use secure settings value, if any. */
+        int defaultDelay = SystemProperties.getInt(
+                "conn." + Settings.Secure.CONNECTIVITY_CHANGE_DELAY,
+                Settings.Secure.CONNECTIVITY_CHANGE_DELAY_DEFAULT);
+        return Settings.Secure.getInt(cr, Settings.Secure.CONNECTIVITY_CHANGE_DELAY,
+                defaultDelay);
+    }
+
     private int getPersistedNetworkPreference() {
         final ContentResolver cr = mContext.getContentResolver();
 
@@ -1243,13 +1260,14 @@ private void handleDisconnect(NetworkInfo info) {
         // do this before we broadcast the change
         handleConnectivityChange(prevNetType, doReset);
 
-        sendStickyBroadcast(intent);
+        sendStickyBroadcastDelayed(intent, getConnectivityChangeDelay());
         /*
          * If the failover network is already connected, then immediately send
          * out a followup broadcast indicating successful failover
          */
         if (mActiveDefaultNetwork != -1) {
-            sendConnectedBroadcast(mNetTrackers[mActiveDefaultNetwork].getNetworkInfo());
+            sendConnectedBroadcastDelayed(mNetTrackers[mActiveDefaultNetwork].getNetworkInfo(),
+                    getConnectivityChangeDelay());
         }
     }
 
@@ -1303,11 +1321,15 @@ private void sendConnectedBroadcast(NetworkInfo info) {
         sendGeneralBroadcast(info, ConnectivityManager.CONNECTIVITY_ACTION);
     }
 
+    private void sendConnectedBroadcastDelayed(NetworkInfo info, int delayMs) {
+        sendGeneralBroadcastDelayed(info, ConnectivityManager.CONNECTIVITY_ACTION, delayMs);
+    }
+
     private void sendInetConditionBroadcast(NetworkInfo info) {
         sendGeneralBroadcast(info, ConnectivityManager.INET_CONDITION_ACTION);
     }
 
-    private void sendGeneralBroadcast(NetworkInfo info, String bcastType) {
+    private Intent makeGeneralIntent(NetworkInfo info, String bcastType) {
         Intent intent = new Intent(bcastType);
         intent.putExtra(ConnectivityManager.EXTRA_NETWORK_INFO, info);
         if (info.isFailover()) {
@@ -1322,7 +1344,15 @@ private void sendGeneralBroadcast(NetworkInfo info, String bcastType) {
                     info.getExtraInfo());
         }
         intent.putExtra(ConnectivityManager.EXTRA_INET_CONDITION, mDefaultInetConditionPublished);
-        sendStickyBroadcast(intent);
+        return intent;
+    }
+
+    private void sendGeneralBroadcast(NetworkInfo info, String bcastType) {
+        sendStickyBroadcast(makeGeneralIntent(info, bcastType));
+    }
+
+    private void sendGeneralBroadcastDelayed(NetworkInfo info, String bcastType, int delayMs) {
+        sendStickyBroadcastDelayed(makeGeneralIntent(info, bcastType), delayMs);
     }
 
     /**
@@ -1387,10 +1417,25 @@ private void sendStickyBroadcast(Intent intent) {
                 mInitialBroadcast = new Intent(intent);
             }
             intent.addFlags(Intent.FLAG_RECEIVER_REGISTERED_ONLY_BEFORE_BOOT);
+            if (DBG) {
+                log("sendStickyBroadcast: NetworkInfo=" +
+                    intent.getParcelableExtra(ConnectivityManager.EXTRA_NETWORK_INFO));
+            }
+
             mContext.sendStickyBroadcast(intent);
         }
     }
 
+    private void sendStickyBroadcastDelayed(Intent intent, int delayMs) {
+        if (delayMs <= 0) {
+            sendStickyBroadcast(intent);
+        } else {
+            if (DBG) log("sendStickyBroadcastDelayed: delayMs=" + delayMs + " intent=" + intent);
+            mHandler.sendMessageDelayed(mHandler.obtainMessage(
+                    EVENT_SEND_STICKY_BROADCAST_INTENT, intent), delayMs);
+        }
+    }
+
     void systemReady() {
         IBinder b = ServiceManager.getService(Context.NETWORKMANAGEMENT_SERVICE);
         mNetd = INetworkManagementService.Stub.asInterface(b);
@@ -1466,7 +1511,7 @@ private void handleConnect(NetworkInfo info) {
         thisNet.setTeardownRequested(false);
         updateNetworkSettings(thisNet);
         handleConnectivityChange(type, false);
-        sendConnectedBroadcast(info);
+        sendConnectedBroadcastDelayed(info, getConnectivityChangeDelay());
     }
 
     /**
@@ -2036,6 +2081,13 @@ public void handleMessage(Message msg) {
                     handleSetDependencyMet(msg.arg2, met);
                     break;
                 }
+                case EVENT_SEND_STICKY_BROADCAST_INTENT:
+                {
+                    Intent intent = (Intent)msg.obj;
+                    log("EVENT_SEND_STICKY_BROADCAST_INTENT: sendStickyBroadcast intent=" + intent);
+                    sendStickyBroadcast(intent);
+                    break;
+                }
             }
         }
     }
@@ -2222,10 +2274,13 @@ private void handleInetConditionHoldEnd(int netType, int sequence) {
             if (DBG) log("event hold for obsolete network - aborting");
             return;
         }
-        if (mDefaultInetConditionPublished == mDefaultInetCondition) {
-            if (DBG) log("no change in condition - aborting");
-            return;
-        }
+        // TODO: Figure out why this optimization sometimes causes a
+        //       change in mDefaultInetCondition to be missed and the
+        //       UI to not be updated.
+        //if (mDefaultInetConditionPublished == mDefaultInetCondition) {
+        //    if (DBG) log("no change in condition - aborting");
+        //    return;
+        //}
         NetworkInfo networkInfo = mNetTrackers[mActiveDefaultNetwork].getNetworkInfo();
         if (networkInfo.isConnected() == false) {
             if (DBG) log("default network not connected - aborting");