Sample network statistics for sanity check.

After detailed poll events, sample high-level network statistics to
sanity check iface totals against UID totals.

Bug: 5248382
Change-Id: I1c1fbb7c094c9ff0c9dde416467c563dda68f478

core/java/android/net/NetworkStats.java

@@ -320,15 +320,36 @@ public class NetworkStats implements Parcelable {
      * checking if a {@link #subtract(NetworkStats)} delta passes a threshold.
      */
     public long getTotalBytes() {
-        long totalBytes = 0;
+        final Entry entry = getTotal(null);
+        return entry.rxBytes + entry.txBytes;
+    }
+
+    /**
+     * Return total of all fields represented by this snapshot object.
+     */
+    public Entry getTotal(Entry recycle) {
+        final Entry entry = recycle != null ? recycle : new Entry();
+
+        entry.iface = IFACE_ALL;
+        entry.uid = UID_ALL;
+        entry.set = SET_ALL;
+        entry.tag = TAG_NONE;
+        entry.rxBytes = 0;
+        entry.rxPackets = 0;
+        entry.txBytes = 0;
+        entry.txPackets = 0;
+
         for (int i = 0; i < size; i++) {
             // skip specific tags, since already counted in TAG_NONE
             if (tag[i] != TAG_NONE) continue;
 
-            totalBytes += rxBytes[i];
+            entry.rxBytes += rxBytes[i];
-            totalBytes += txBytes[i];
+            entry.rxPackets += rxPackets[i];
+            entry.txBytes += txBytes[i];
+            entry.txPackets += txPackets[i];
+            entry.operations += operations[i];
         }
-        return totalBytes;
+        return entry;
     }
 
     /**

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

@@ -31,6 +31,8 @@ import static android.net.NetworkStats.SET_DEFAULT;
 import static android.net.NetworkStats.SET_FOREGROUND;
 import static android.net.NetworkStats.TAG_NONE;
 import static android.net.NetworkStats.UID_ALL;
+import static android.net.NetworkTemplate.buildTemplateMobileAll;
+import static android.net.NetworkTemplate.buildTemplateWifi;
 import static android.net.TrafficStats.UID_REMOVED;
 import static android.provider.Settings.Secure.NETSTATS_NETWORK_BUCKET_DURATION;
 import static android.provider.Settings.Secure.NETSTATS_NETWORK_MAX_HISTORY;
@@ -76,6 +78,7 @@ import android.os.RemoteException;
 import android.os.SystemClock;
 import android.provider.Settings;
 import android.telephony.TelephonyManager;
+import android.util.EventLog;
 import android.util.NtpTrustedTime;
 import android.util.Slog;
 import android.util.SparseIntArray;
@@ -83,6 +86,7 @@ import android.util.TrustedTime;
 
 import com.android.internal.os.AtomicFile;
 import com.android.internal.util.Objects;
+import com.android.server.EventLogTags;
 import com.google.android.collect.Lists;
 import com.google.android.collect.Maps;
 import com.google.android.collect.Sets;
@@ -387,7 +391,9 @@ public class NetworkStatsService extends INetworkStatsService.Stub {
                     entry.uid = UID_ALL;
                     entry.tag = TAG_NONE;
                     entry.rxBytes = historyEntry.rxBytes;
+                    entry.rxPackets = historyEntry.rxPackets;
                     entry.txBytes = historyEntry.txBytes;
+                    entry.txPackets = historyEntry.txPackets;
 
                     stats.combineValues(entry);
                 }
@@ -716,6 +722,11 @@ public class NetworkStatsService extends INetworkStatsService.Stub {
             Slog.v(TAG, "performPollLocked() took " + duration + "ms");
         }
 
+        // sample stats after detailed poll
+        if (detailedPoll) {
+            performSample();
+        }
+
         // finally, dispatch updated event to any listeners
         final Intent updatedIntent = new Intent(ACTION_NETWORK_STATS_UPDATED);
         updatedIntent.setFlags(Intent.FLAG_RECEIVER_REGISTERED_ONLY);
@@ -808,6 +819,33 @@ public class NetworkStatsService extends INetworkStatsService.Stub {
         mOperations = new NetworkStats(0L, 10);
     }
 
+    /**
+     * Sample recent statistics summary into {@link EventLog}.
+     */
+    private void performSample() {
+        // take sample as total over last 4 hours
+        final long end = mTime.hasCache() ? mTime.currentTimeMillis() : System.currentTimeMillis();
+        final long start = end - (4 * HOUR_IN_MILLIS);
+
+        NetworkTemplate template = null;
+        NetworkStats.Entry ifaceTotal = null;
+        NetworkStats.Entry uidTotal = null;
+
+        // collect mobile sample
+        template = buildTemplateMobileAll(getActiveSubscriberId(mContext));
+        ifaceTotal = getSummaryForNetwork(template, start, end).getTotal(ifaceTotal);
+        uidTotal = getSummaryForAllUid(template, start, end, false).getTotal(uidTotal);
+        EventLogTags.writeNetstatsMobileSample(
+                ifaceTotal.rxBytes, ifaceTotal.txBytes, uidTotal.rxBytes, uidTotal.txBytes);
+
+        // collect wifi sample
+        template = buildTemplateWifi();
+        ifaceTotal = getSummaryForNetwork(template, start, end).getTotal(ifaceTotal);
+        uidTotal = getSummaryForAllUid(template, start, end, false).getTotal(uidTotal);
+        EventLogTags.writeNetstatsWifiSample(
+                ifaceTotal.rxBytes, ifaceTotal.txBytes, uidTotal.rxBytes, uidTotal.txBytes);
+    }
+
     /**
      * Clean up {@link #mUidStats} after UID is removed.
      */
@@ -1249,6 +1287,12 @@ public class NetworkStatsService extends INetworkStatsService.Stub {
         }
     };
 
+    private static String getActiveSubscriberId(Context context) {
+        final TelephonyManager telephony = (TelephonyManager) context.getSystemService(
+                Context.TELEPHONY_SERVICE);
+        return telephony.getSubscriberId();
+    }
+
     /**
      * Key uniquely identifying a {@link NetworkStatsHistory} for a UID.
      */