API to adjust network stats. DO NOT MERGE.

Enables system apps to correctly account network usage performed on
behalf of another application.

Bug: 6695246
Change-Id: I39e243afd57936b6b30157a6ca511a17b6c55c39

Author: jsharkey

core/java/android/net/INetworkStatsService.aidl

@@ -45,4 +45,7 @@ interface INetworkStatsService {
     /** Advise persistance threshold; may be overridden internally. */
     void advisePersistThreshold(long thresholdBytes);
 
+    /** Adjust recorded network stats. */
+    void adjustNetworkStats(int uid, int tag, long rxBytes, long rxPackets, long txBytes, long txPackets, long operationCount);
+
 }

core/java/android/net/TrafficStats.java

@@ -88,6 +88,13 @@ public class TrafficStats {
      */
     public static final int TAG_SYSTEM_BACKUP = 0xFFFFFF03;
 
+    /**
+     * Default tag value for cloud messaging traffic.
+     *
+     * @hide
+     */
+    public static final int TAG_SYSTEM_CLOUD_MESSAGING = 0xFFFFFF04;
+
     private static INetworkStatsService sStatsService;
 
     private synchronized static INetworkStatsService getStatsService() {
@@ -246,6 +253,27 @@ public static void incrementOperationCount(int tag, int operationCount) {
         }
     }
 
+    /**
+     * Adjust network statistics for the given UID and tag by the requested
+     * amount. This can be used to correctly account network usage performed on
+     * behalf of another application. Values can be negative.
+     * <p>
+     * Requires that caller holds
+     * {@link android.Manifest.permission#MODIFY_NETWORK_ACCOUNTING} permission.
+     *
+     * @see #setThreadStatsUid(int)
+     * @hide
+     */
+    public static void adjustNetworkStats(int uid, int tag, long rxBytes, long rxPackets,
+            long txBytes, long txPackets, long operationCount) {
+        try {
+            getStatsService().adjustNetworkStats(
+                    uid, tag, rxBytes, rxPackets, txBytes, txPackets, operationCount);
+        } catch (RemoteException e) {
+            throw new RuntimeException(e);
+        }
+    }
+
     /** {@hide} */
     public static void closeQuietly(INetworkStatsSession session) {
         // TODO: move to NetworkStatsService once it exists

services/java/com/android/server/net/NetworkStatsService.java

@@ -695,6 +695,14 @@ private void updatePersistThresholds() {
         mGlobalAlertBytes = mSettings.getGlobalAlertBytes(mPersistThreshold);
     }
 
+    @Override
+    public void adjustNetworkStats(int uid, int tag, long rxBytes, long rxPackets, long txBytes,
+            long txPackets, long operationCount) {
+        mContext.enforceCallingOrSelfPermission(MODIFY_NETWORK_ACCOUNTING, TAG);
+
+        // TODO: store adjusted network stats in separate data structure
+    }
+
     /**
      * Receiver that watches for {@link IConnectivityManager} to claim network
      * interfaces. Used to associate {@link TelephonyManager#getSubscriberId()}