Added a virtual interface for Video Telephony call usage counting

1. Added a virtual VT interface.
2. Qeury VT usage from telephony service.

bug: 20888836
Change-Id: I3df0c22922f8394554230b53f8ae091e17c95595

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

@@ -31,6 +31,7 @@ import static android.net.NetworkStats.IFACE_ALL;
 import static android.net.NetworkStats.SET_ALL;
 import static android.net.NetworkStats.SET_DEFAULT;
 import static android.net.NetworkStats.SET_FOREGROUND;
+import static android.net.NetworkStats.TAG_ALL;
 import static android.net.NetworkStats.TAG_NONE;
 import static android.net.NetworkStats.UID_ALL;
 import static android.net.NetworkTemplate.buildTemplateMobileWildcard;
@@ -79,6 +80,7 @@ import android.net.INetworkManagementEventObserver;
 import android.net.INetworkStatsService;
 import android.net.INetworkStatsSession;
 import android.net.LinkProperties;
+import android.net.NetworkCapabilities;
 import android.net.NetworkIdentity;
 import android.net.NetworkInfo;
 import android.net.NetworkState;
@@ -178,6 +180,11 @@ public class NetworkStatsService extends INetworkStatsService.Stub {
     private static final String PREFIX_UID = "uid";
     private static final String PREFIX_UID_TAG = "uid_tag";
 
+    /**
+     * Virtual network interface for video telephony. This is for VT data usage counting purpose.
+     */
+    public static final String VT_INTERFACE = "vt_data0";
+
     /**
      * Settings that can be changed externally.
      */
@@ -967,6 +974,23 @@ public class NetworkStatsService extends INetworkStatsService.Stub {
                 if (baseIface != null) {
                     findOrCreateNetworkIdentitySet(mActiveIfaces, baseIface).add(ident);
                     findOrCreateNetworkIdentitySet(mActiveUidIfaces, baseIface).add(ident);
+
+                    // Build a separate virtual interface for VT (Video Telephony) data usage.
+                    // Only do this when IMS is not metered, but VT is metered.
+                    // If IMS is metered, then the IMS network usage has already included VT usage.
+                    // VT is considered always metered in framework's layer. If VT is not metered
+                    // per carrier's policy, modem will report 0 usage for VT calls.
+                    if (state.networkCapabilities.hasCapability(
+                            NetworkCapabilities.NET_CAPABILITY_IMS) && !ident.getMetered()) {
+
+                        // Copy the identify from IMS one but mark it as metered.
+                        NetworkIdentity vtIdent = new NetworkIdentity(ident.getType(),
+                                ident.getSubType(), ident.getSubscriberId(), ident.getNetworkId(),
+                                ident.getRoaming(), true);
+                        findOrCreateNetworkIdentitySet(mActiveIfaces, VT_INTERFACE).add(vtIdent);
+                        findOrCreateNetworkIdentitySet(mActiveUidIfaces, VT_INTERFACE).add(vtIdent);
+                    }
+
                     if (isMobile) {
                         mobileIfaces.add(baseIface);
                     }
@@ -1004,9 +1028,9 @@ public class NetworkStatsService extends INetworkStatsService.Stub {
 
     private void recordSnapshotLocked(long currentTime) throws RemoteException {
         // snapshot and record current counters; read UID stats first to
-        // avoid overcounting dev stats.
+        // avoid over counting dev stats.
         final NetworkStats uidSnapshot = getNetworkStatsUidDetail();
-        final NetworkStats xtSnapshot = mNetworkManager.getNetworkStatsSummaryXt();
+        final NetworkStats xtSnapshot = getNetworkStatsXtAndVt();
         final NetworkStats devSnapshot = mNetworkManager.getNetworkStatsSummaryDev();
 
 
@@ -1311,6 +1335,42 @@ public class NetworkStatsService extends INetworkStatsService.Stub {
         return uidSnapshot;
     }
 
+    /**
+     * Return snapshot of current XT plus VT statistics.
+     */
+    private NetworkStats getNetworkStatsXtAndVt() throws RemoteException {
+        final NetworkStats xtSnapshot = mNetworkManager.getNetworkStatsSummaryXt();
+
+        TelephonyManager tm = (TelephonyManager) mContext.getSystemService(
+                Context.TELEPHONY_SERVICE);
+
+        long usage = tm.getVtDataUsage();
+
+        if (LOGV) Slog.d(TAG, "VT call data usage = " + usage);
+
+        final NetworkStats vtSnapshot = new NetworkStats(SystemClock.elapsedRealtime(), 1);
+
+        final NetworkStats.Entry entry = new NetworkStats.Entry();
+        entry.iface = VT_INTERFACE;
+        entry.uid = -1;
+        entry.set = TAG_ALL;
+        entry.tag = TAG_NONE;
+
+        // Since modem only tell us the total usage instead of each usage for RX and TX,
+        // we need to split it up (though it might not quite accurate). At
+        // least we can make sure the data usage report to the user will still be accurate.
+        entry.rxBytes = usage / 2;
+        entry.rxPackets = 0;
+        entry.txBytes = usage - entry.rxBytes;
+        entry.txPackets = 0;
+        vtSnapshot.combineValues(entry);
+
+        // Merge VT int XT
+        xtSnapshot.combineAllValues(vtSnapshot);
+
+        return xtSnapshot;
+    }
+
     /**
      * Return snapshot of current tethering statistics. Will return empty
      * {@link NetworkStats} if any problems are encountered.