Add wifi multicast filter api (enable/disable).

Fixes 1833432.  Automatically re-disables any request when the app
exits/crashes.  Also hooked into Battery Stats for power managment analysis.

3 files changed, 76 insertions, 5 deletions

diff --git a/wifi/java/android/net/wifi/IWifiManager.aidl b/wifi/java/android/net/wifi/IWifiManager.aidl
index f9a0845..00829d6 100644
--- a/wifi/java/android/net/wifi/IWifiManager.aidl
+++ b/wifi/java/android/net/wifi/IWifiManager.aidl
@@ -69,5 +69,11 @@ interface IWifiManager
     boolean acquireWifiLock(IBinder lock, int lockType, String tag);
 
     boolean releaseWifiLock(IBinder lock);
+
+    boolean isWifiMulticastEnabled();
+
+    void enableWifiMulticast(IBinder binder, String tag);
+
+    void disableWifiMulticast();
 }
 
diff --git a/wifi/java/android/net/wifi/WifiManager.java b/wifi/java/android/net/wifi/WifiManager.java
index a51e88f..658a7b2 100644
--- a/wifi/java/android/net/wifi/WifiManager.java
+++ b/wifi/java/android/net/wifi/WifiManager.java
@@ -823,4 +823,65 @@ public class WifiManager {
     public WifiLock createWifiLock(String tag) {
         return new WifiLock(WIFI_MODE_FULL, tag);
     }
+
+    /**
+     * Check multicast filter status.
+     *
+     * @return true if multicast packets are allowed.
+     *
+     * @hide pending API council approval
+     */
+    public boolean isWifiMulticastEnabled() {
+        try {
+            return mService.isWifiMulticastEnabled();
+        } catch (RemoteException e) {
+            return false;
+        }
+    }
+
+    /**
+     * Turn on the reception of multicast packets.
+     * The default behavior is to disable multicast packets as they
+     * have a noticable negative effect on battery life.  An
+     * application can turn them on, but should not leave it on for longer
+     * than needed.  When the app quits (or crashes) its request will
+     * be reverted.
+     *
+     * @param tag a string associated with this request for debugging.
+     *
+     * @return true on success
+     *
+     * @see #disableWifiMulticast
+     *
+     * @hide pending API council approval
+     */
+    public boolean enableWifiMulticast(String tag) {
+        try {
+            mService.enableWifiMulticast(new Binder(), tag);
+            return true;
+        } catch (RemoteException e) {
+            return false;
+        }
+    }
+
+    /**
+     * Return to the default multicast-off setting.
+     * Note that if others had turned on Multicast reception, your
+     * call will not turn it back off - they must also turn off their
+     * request for multicast reception.
+     *
+     * @return true on success
+     *
+     * @see #enableWifiMulticast
+     *
+     * @hide pending API council approval
+     */
+    public boolean disableWifiMulticast() {
+        try {
+            mService.disableWifiMulticast();
+            return true;
+        } catch (RemoteException e) {
+            return false;
+        }
+    }
 }
diff --git a/wifi/java/android/net/wifi/WifiStateTracker.java b/wifi/java/android/net/wifi/WifiStateTracker.java
index 6ea35f5..64084cf 100644
--- a/wifi/java/android/net/wifi/WifiStateTracker.java
+++ b/wifi/java/android/net/wifi/WifiStateTracker.java
@@ -732,15 +732,19 @@ public class WifiStateTracker extends NetworkStateTracker {
                 /*
                  * Filter out multicast packets. This saves battery power, since
                  * the CPU doesn't have to spend time processing packets that
-                 * are going to end up being thrown away. Obviously, if we
-                 * ever want to support multicast, this will have to change.
+                 * are going to end up being thrown away.
+                 *
+                 * Note that rather than turn this off directly, we use the
+                 * public api - this keeps us all in sync - turn multicast on
+                 * first and then off.. if nobody else wants it on it'll be
+                 * off then and it's all synchronized within the API.
                  */
+                mWM.enableWifiMulticast("WifiStateTracker");
+                mWM.disableWifiMulticast();
+
                 if (mBluetoothA2dp == null) {
                     mBluetoothA2dp = new BluetoothA2dp(mContext);
                 }
-                synchronized (this) {
-                    WifiNative.startPacketFiltering();
-                }
                 checkIsBluetoothPlaying();
                 break;