[SP06] Use system API to communicate with NSS in OffloadController

Test: atest FrameworksNetTests OffloadControllerTest TetheringTest
Bug: 130855321

Change-Id: I294be3a2874f8c8120857e308e629199af014fcd

5 files changed, 211 insertions, 132 deletions

diff --git a/packages/Tethering/src/com/android/server/connectivity/tethering/OffloadController.java b/packages/Tethering/src/com/android/server/connectivity/tethering/OffloadController.java
index ce7c2a669f0a..cc36f4a9c516 100644
--- a/packages/Tethering/src/com/android/server/connectivity/tethering/OffloadController.java
+++ b/packages/Tethering/src/com/android/server/connectivity/tethering/OffloadController.java
@@ -16,35 +16,40 @@
 
 package com.android.server.connectivity.tethering;
 
+import static android.net.NetworkStats.DEFAULT_NETWORK_NO;
+import static android.net.NetworkStats.METERED_NO;
+import static android.net.NetworkStats.ROAMING_NO;
 import static android.net.NetworkStats.SET_DEFAULT;
-import static android.net.NetworkStats.STATS_PER_UID;
 import static android.net.NetworkStats.TAG_NONE;
 import static android.net.NetworkStats.UID_ALL;
-import static android.net.TrafficStats.UID_TETHERING;
+import static android.net.NetworkStats.UID_TETHERING;
 import static android.provider.Settings.Global.TETHER_OFFLOAD_DISABLED;
 
+import android.annotation.NonNull;
+import android.annotation.Nullable;
+import android.app.usage.NetworkStatsManager;
 import android.content.ContentResolver;
-import android.net.ITetheringStatsProvider;
 import android.net.InetAddresses;
 import android.net.IpPrefix;
 import android.net.LinkAddress;
 import android.net.LinkProperties;
 import android.net.NetworkStats;
+import android.net.NetworkStats.Entry;
 import android.net.RouteInfo;
 import android.net.netlink.ConntrackMessage;
 import android.net.netlink.NetlinkConstants;
 import android.net.netlink.NetlinkSocket;
+import android.net.netstats.provider.AbstractNetworkStatsProvider;
+import android.net.netstats.provider.NetworkStatsProviderCallback;
 import android.net.util.SharedLog;
 import android.os.Handler;
-import android.os.INetworkManagementService;
-import android.os.Looper;
-import android.os.RemoteException;
-import android.os.SystemClock;
 import android.provider.Settings;
 import android.system.ErrnoException;
 import android.system.OsConstants;
 import android.text.TextUtils;
+import android.util.Log;
 
+import com.android.internal.annotations.VisibleForTesting;
 import com.android.internal.util.IndentingPrintWriter;
 import com.android.server.connectivity.tethering.OffloadHardwareInterface.ForwardedStats;
 
@@ -73,13 +78,19 @@ public class OffloadController {
     private static final String ANYIP = "0.0.0.0";
     private static final ForwardedStats EMPTY_STATS = new ForwardedStats();
 
+    @VisibleForTesting
+    enum StatsType {
+        STATS_PER_IFACE,
+        STATS_PER_UID,
+    }
+
     private enum UpdateType { IF_NEEDED, FORCE };
 
     private final Handler mHandler;
     private final OffloadHardwareInterface mHwInterface;
     private final ContentResolver mContentResolver;
-    private final INetworkManagementService mNms;
-    private final ITetheringStatsProvider mStatsProvider;
+    private final @NonNull OffloadTetheringStatsProvider mStatsProvider;
+    private final @Nullable NetworkStatsProviderCallback mStatsProviderCb;
     private final SharedLog mLog;
     private final HashMap<String, LinkProperties> mDownstreams;
     private boolean mConfigInitialized;
@@ -109,22 +120,23 @@ public class OffloadController {
     private int mNatUpdateNetlinkErrors;
 
     public OffloadController(Handler h, OffloadHardwareInterface hwi,
-            ContentResolver contentResolver, INetworkManagementService nms, SharedLog log) {
+            ContentResolver contentResolver, NetworkStatsManager nsm, SharedLog log) {
         mHandler = h;
         mHwInterface = hwi;
         mContentResolver = contentResolver;
-        mNms = nms;
         mStatsProvider = new OffloadTetheringStatsProvider();
         mLog = log.forSubComponent(TAG);
         mDownstreams = new HashMap<>();
         mExemptPrefixes = new HashSet<>();
         mLastLocalPrefixStrs = new HashSet<>();
-
+        NetworkStatsProviderCallback providerCallback = null;
         try {
-            mNms.registerTetheringStatsProvider(mStatsProvider, getClass().getSimpleName());
-        } catch (RemoteException e) {
-            mLog.e("Cannot register offload stats provider: " + e);
+            providerCallback = nsm.registerNetworkStatsProvider(
+                    getClass().getSimpleName(), mStatsProvider);
+        } catch (RuntimeException e) {
+            Log.wtf(TAG, "Cannot register offload stats provider: " + e);
         }
+        mStatsProviderCb = providerCallback;
     }
 
     /** Start hardware offload. */
@@ -173,7 +185,7 @@ public class OffloadController {
                         // and we need to synchronize stats and limits between
                         // software and hardware forwarding.
                         updateStatsForAllUpstreams();
-                        forceTetherStatsPoll();
+                        mStatsProvider.pushTetherStats();
                     }
 
                     @Override
@@ -186,7 +198,7 @@ public class OffloadController {
                         // limits set take into account any software tethering
                         // traffic that has been happening in the meantime.
                         updateStatsForAllUpstreams();
-                        forceTetherStatsPoll();
+                        mStatsProvider.pushTetherStats();
                         // [2] (Re)Push all state.
                         computeAndPushLocalPrefixes(UpdateType.FORCE);
                         pushAllDownstreamState();
@@ -204,14 +216,11 @@ public class OffloadController {
                         // the HAL queued the callback.
                         // TODO: rev the HAL so that it provides an interface name.
 
-                        // Fetch current stats, so that when our notification reaches
-                        // NetworkStatsService and triggers a poll, we will respond with
-                        // current data (which will be above the limit that was reached).
-                        // Note that if we just changed upstream, this is unnecessary but harmless.
-                        // The stats for the previous upstream were already updated on this thread
-                        // just after the upstream was changed, so they are also up-to-date.
                         updateStatsForCurrentUpstream();
-                        forceTetherStatsPoll();
+                        mStatsProvider.pushTetherStats();
+                        // Push stats to service does not cause the service react to it immediately.
+                        // Inform the service about limit reached.
+                        if (mStatsProviderCb != null) mStatsProviderCb.onLimitReached();
                     }
 
                     @Override
@@ -253,42 +262,37 @@ public class OffloadController {
         return mConfigInitialized && mControlInitialized;
     }
 
-    private class OffloadTetheringStatsProvider extends ITetheringStatsProvider.Stub {
-        @Override
-        public NetworkStats getTetherStats(int how) {
-            // getTetherStats() is the only function in OffloadController that can be called from
-            // a different thread. Do not attempt to update stats by querying the offload HAL
-            // synchronously from a different thread than our Handler thread. http://b/64771555.
-            Runnable updateStats = () -> {
-                updateStatsForCurrentUpstream();
-            };
-            if (Looper.myLooper() == mHandler.getLooper()) {
-                updateStats.run();
-            } else {
-                mHandler.post(updateStats);
-            }
-
-            NetworkStats stats = new NetworkStats(SystemClock.elapsedRealtime(), 0);
-            NetworkStats.Entry entry = new NetworkStats.Entry();
-            entry.set = SET_DEFAULT;
-            entry.tag = TAG_NONE;
-            entry.uid = (how == STATS_PER_UID) ? UID_TETHERING : UID_ALL;
-
-            for (Map.Entry<String, ForwardedStats> kv : mForwardedStats.entrySet()) {
-                ForwardedStats value = kv.getValue();
-                entry.iface = kv.getKey();
-                entry.rxBytes = value.rxBytes;
-                entry.txBytes = value.txBytes;
-                stats.addEntry(entry);
+    @VisibleForTesting
+    class OffloadTetheringStatsProvider extends AbstractNetworkStatsProvider {
+        // These stats must only ever be touched on the handler thread.
+        @NonNull
+        private NetworkStats mIfaceStats = new NetworkStats(0L, 0);
+        @NonNull
+        private NetworkStats mUidStats = new NetworkStats(0L, 0);
+
+        @VisibleForTesting
+        @NonNull
+        NetworkStats getTetherStats(@NonNull StatsType how) {
+            NetworkStats stats = new NetworkStats(0L, 0);
+            final int uid = (how == StatsType.STATS_PER_UID) ? UID_TETHERING : UID_ALL;
+
+            for (final Map.Entry<String, ForwardedStats> kv : mForwardedStats.entrySet()) {
+                final ForwardedStats value = kv.getValue();
+                final Entry entry = new Entry(kv.getKey(), uid, SET_DEFAULT, TAG_NONE, METERED_NO,
+                        ROAMING_NO, DEFAULT_NETWORK_NO, value.rxBytes, 0L, value.txBytes, 0L, 0L);
+                stats = stats.addValues(entry);
             }
 
             return stats;
         }
 
         @Override
-        public void setInterfaceQuota(String iface, long quotaBytes) {
+        public void setLimit(String iface, long quotaBytes) {
+            mLog.i("setLimit: " + iface + "," + quotaBytes);
+            // Listen for all iface is necessary since upstream might be changed after limit
+            // is set.
             mHandler.post(() -> {
-                if (quotaBytes == ITetheringStatsProvider.QUOTA_UNLIMITED) {
+                if (quotaBytes == QUOTA_UNLIMITED) {
                     mInterfaceQuotas.remove(iface);
                 } else {
                     mInterfaceQuotas.put(iface, quotaBytes);
@@ -296,6 +300,42 @@ public class OffloadController {
                 maybeUpdateDataLimit(iface);
             });
         }
+
+        /**
+         * Push stats to service, but does not cause a force polling. Note that this can only be
+         * called on the handler thread.
+         */
+        public void pushTetherStats() {
+            // TODO: remove the accumulated stats and report the diff from HAL directly.
+            if (null == mStatsProviderCb) return;
+            final NetworkStats ifaceDiff =
+                    getTetherStats(StatsType.STATS_PER_IFACE).subtract(mIfaceStats);
+            final NetworkStats uidDiff =
+                    getTetherStats(StatsType.STATS_PER_UID).subtract(mUidStats);
+            try {
+                mStatsProviderCb.onStatsUpdated(0 /* token */, ifaceDiff, uidDiff);
+                mIfaceStats = mIfaceStats.add(ifaceDiff);
+                mUidStats = mUidStats.add(uidDiff);
+            } catch (RuntimeException e) {
+                mLog.e("Cannot report network stats: ", e);
+            }
+        }
+
+        @Override
+        public void requestStatsUpdate(int token) {
+            mLog.i("requestStatsUpdate: " + token);
+            // Do not attempt to update stats by querying the offload HAL
+            // synchronously from a different thread than the Handler thread. http://b/64771555.
+            mHandler.post(() -> {
+                updateStatsForCurrentUpstream();
+                pushTetherStats();
+            });
+        }
+
+        @Override
+        public void setAlert(long quotaBytes) {
+            // TODO: Ask offload HAL to notify alert without stopping traffic.
+        }
     }
 
     private String currentUpstreamInterface() {
@@ -353,14 +393,6 @@ public class OffloadController {
         }
     }
 
-    private void forceTetherStatsPoll() {
-        try {
-            mNms.tetherLimitReached(mStatsProvider);
-        } catch (RemoteException e) {
-            mLog.e("Cannot report data limit reached: " + e);
-        }
-    }
-
     /** Set current tethering upstream LinkProperties. */
     public void setUpstreamLinkProperties(LinkProperties lp) {
         if (!started() || Objects.equals(mUpstreamLinkProperties, lp)) return;
diff --git a/packages/Tethering/src/com/android/server/connectivity/tethering/OffloadHardwareInterface.java b/packages/Tethering/src/com/android/server/connectivity/tethering/OffloadHardwareInterface.java
index 4a8ef1f92754..90b9d3f148dc 100644
--- a/packages/Tethering/src/com/android/server/connectivity/tethering/OffloadHardwareInterface.java
+++ b/packages/Tethering/src/com/android/server/connectivity/tethering/OffloadHardwareInterface.java
@@ -29,6 +29,8 @@ import android.os.Handler;
 import android.os.RemoteException;
 import android.system.OsConstants;
 
+import com.android.internal.annotations.VisibleForTesting;
+
 import java.util.ArrayList;
 
 
@@ -91,6 +93,12 @@ public class OffloadHardwareInterface {
             txBytes = 0;
         }
 
+        @VisibleForTesting
+        public ForwardedStats(long rxBytes, long txBytes) {
+            this.rxBytes = rxBytes;
+            this.txBytes = txBytes;
+        }
+
         /** Add Tx/Rx bytes. */
         public void add(ForwardedStats other) {
             rxBytes += other.rxBytes;
diff --git a/packages/Tethering/src/com/android/server/connectivity/tethering/Tethering.java b/packages/Tethering/src/com/android/server/connectivity/tethering/Tethering.java
index 5b97f50f1208..0ee8164f3b90 100644
--- a/packages/Tethering/src/com/android/server/connectivity/tethering/Tethering.java
+++ b/packages/Tethering/src/com/android/server/connectivity/tethering/Tethering.java
@@ -53,6 +53,7 @@ import android.app.Notification;
 import android.app.NotificationChannel;
 import android.app.NotificationManager;
 import android.app.PendingIntent;
+import android.app.usage.NetworkStatsManager;
 import android.bluetooth.BluetoothAdapter;
 import android.bluetooth.BluetoothPan;
 import android.bluetooth.BluetoothProfile;
@@ -224,10 +225,11 @@ public class Tethering {
         mTetherMasterSM = new TetherMasterSM("TetherMaster", mLooper, deps);
         mTetherMasterSM.start();
 
+        final NetworkStatsManager statsManager = new NetworkStatsManager(mContext, mStatsService);
         mHandler = mTetherMasterSM.getHandler();
         mOffloadController = new OffloadController(mHandler,
                 mDeps.getOffloadHardwareInterface(mHandler, mLog), mContext.getContentResolver(),
-                mDeps.getINetworkManagementService(), mLog);
+                statsManager, mLog);
         mUpstreamNetworkMonitor = mDeps.getUpstreamNetworkMonitor(mContext, mTetherMasterSM, mLog,
                 TetherMasterSM.EVENT_UPSTREAM_CALLBACK);
         mForwardedDownstreams = new HashSet<>();
@@ -264,7 +266,7 @@ public class Tethering {
         }
 
         final UserManager userManager = (UserManager) mContext.getSystemService(
-                    Context.USER_SERVICE);
+                Context.USER_SERVICE);
         mTetheringRestriction = new UserRestrictionActionListener(userManager, this);
         final TetheringThreadExecutor executor = new TetheringThreadExecutor(mHandler);
         mActiveDataSubIdListener = new ActiveDataSubIdListener(executor);
diff --git a/packages/Tethering/tests/unit/src/com/android/server/connectivity/tethering/OffloadControllerTest.java b/packages/Tethering/tests/unit/src/com/android/server/connectivity/tethering/OffloadControllerTest.java
index 7886ca6c132d..7e62e5aca993 100644
--- a/packages/Tethering/tests/unit/src/com/android/server/connectivity/tethering/OffloadControllerTest.java
+++ b/packages/Tethering/tests/unit/src/com/android/server/connectivity/tethering/OffloadControllerTest.java
@@ -16,21 +16,26 @@
 
 package com.android.server.connectivity.tethering;
 
+import static android.net.NetworkStats.DEFAULT_NETWORK_NO;
+import static android.net.NetworkStats.METERED_NO;
+import static android.net.NetworkStats.ROAMING_NO;
 import static android.net.NetworkStats.SET_DEFAULT;
-import static android.net.NetworkStats.STATS_PER_IFACE;
-import static android.net.NetworkStats.STATS_PER_UID;
 import static android.net.NetworkStats.TAG_NONE;
 import static android.net.NetworkStats.UID_ALL;
+import static android.net.NetworkStats.UID_TETHERING;
 import static android.net.RouteInfo.RTN_UNICAST;
-import static android.net.TrafficStats.UID_TETHERING;
 import static android.provider.Settings.Global.TETHER_OFFLOAD_DISABLED;
 
+import static com.android.server.connectivity.tethering.OffloadController.StatsType.STATS_PER_IFACE;
+import static com.android.server.connectivity.tethering.OffloadController.StatsType.STATS_PER_UID;
 import static com.android.server.connectivity.tethering.OffloadHardwareInterface.ForwardedStats;
 import static com.android.testutils.MiscAssertsKt.assertContainsAll;
 import static com.android.testutils.MiscAssertsKt.assertThrows;
+import static com.android.testutils.NetworkStatsUtilsKt.orderInsensitiveEquals;
 
 import static org.junit.Assert.assertEquals;
 import static org.junit.Assert.assertTrue;
+import static org.mockito.ArgumentMatchers.anyInt;
 import static org.mockito.Matchers.any;
 import static org.mockito.Matchers.anyLong;
 import static org.mockito.Matchers.anyObject;
@@ -39,11 +44,14 @@ import static org.mockito.Matchers.eq;
 import static org.mockito.Mockito.clearInvocations;
 import static org.mockito.Mockito.inOrder;
 import static org.mockito.Mockito.never;
+import static org.mockito.Mockito.reset;
 import static org.mockito.Mockito.times;
 import static org.mockito.Mockito.verify;
 import static org.mockito.Mockito.verifyNoMoreInteractions;
 import static org.mockito.Mockito.when;
 
+import android.annotation.NonNull;
+import android.app.usage.NetworkStatsManager;
 import android.content.Context;
 import android.content.pm.ApplicationInfo;
 import android.net.ITetheringStatsProvider;
@@ -51,10 +59,12 @@ import android.net.IpPrefix;
 import android.net.LinkAddress;
 import android.net.LinkProperties;
 import android.net.NetworkStats;
+import android.net.NetworkStats.Entry;
 import android.net.RouteInfo;
+import android.net.netstats.provider.AbstractNetworkStatsProvider;
+import android.net.netstats.provider.NetworkStatsProviderCallback;
 import android.net.util.SharedLog;
 import android.os.Handler;
-import android.os.INetworkManagementService;
 import android.os.Looper;
 import android.provider.Settings;
 import android.provider.Settings.SettingNotFoundException;
@@ -97,11 +107,13 @@ public class OffloadControllerTest {
     @Mock private OffloadHardwareInterface mHardware;
     @Mock private ApplicationInfo mApplicationInfo;
     @Mock private Context mContext;
-    @Mock private INetworkManagementService mNMService;
+    @Mock private NetworkStatsManager mStatsManager;
+    @Mock private NetworkStatsProviderCallback mTetherStatsProviderCb;
     private final ArgumentCaptor<ArrayList> mStringArrayCaptor =
             ArgumentCaptor.forClass(ArrayList.class);
-    private final ArgumentCaptor<ITetheringStatsProvider.Stub> mTetherStatsProviderCaptor =
-            ArgumentCaptor.forClass(ITetheringStatsProvider.Stub.class);
+    private final ArgumentCaptor<OffloadController.OffloadTetheringStatsProvider>
+            mTetherStatsProviderCaptor =
+            ArgumentCaptor.forClass(OffloadController.OffloadTetheringStatsProvider.class);
     private final ArgumentCaptor<OffloadHardwareInterface.ControlCallback> mControlCallbackCaptor =
             ArgumentCaptor.forClass(OffloadHardwareInterface.ControlCallback.class);
     private MockContentResolver mContentResolver;
@@ -114,6 +126,8 @@ public class OffloadControllerTest {
         mContentResolver.addProvider(Settings.AUTHORITY, new FakeSettingsProvider());
         when(mContext.getContentResolver()).thenReturn(mContentResolver);
         FakeSettingsProvider.clearSettingsProvider();
+        when(mStatsManager.registerNetworkStatsProvider(anyString(), any()))
+                .thenReturn(mTetherStatsProviderCb);
     }
 
     @After public void tearDown() throws Exception {
@@ -139,9 +153,9 @@ public class OffloadControllerTest {
 
     private OffloadController makeOffloadController() throws Exception {
         OffloadController offload = new OffloadController(new Handler(Looper.getMainLooper()),
-                mHardware, mContentResolver, mNMService, new SharedLog("test"));
-        verify(mNMService).registerTetheringStatsProvider(
-                mTetherStatsProviderCaptor.capture(), anyString());
+                mHardware, mContentResolver, mStatsManager, new SharedLog("test"));
+        verify(mStatsManager).registerNetworkStatsProvider(anyString(),
+                mTetherStatsProviderCaptor.capture());
         return offload;
     }
 
@@ -384,12 +398,11 @@ public class OffloadControllerTest {
         inOrder.verifyNoMoreInteractions();
     }
 
-    private void assertNetworkStats(String iface, ForwardedStats stats, NetworkStats.Entry entry) {
-        assertEquals(iface, entry.iface);
-        assertEquals(stats.rxBytes, entry.rxBytes);
-        assertEquals(stats.txBytes, entry.txBytes);
-        assertEquals(SET_DEFAULT, entry.set);
-        assertEquals(TAG_NONE, entry.tag);
+    private static @NonNull Entry buildTestEntry(@NonNull OffloadController.StatsType how,
+            @NonNull String iface, long rxBytes, long txBytes) {
+        return new Entry(iface, how == STATS_PER_IFACE ? UID_ALL : UID_TETHERING, SET_DEFAULT,
+                TAG_NONE, METERED_NO, ROAMING_NO, DEFAULT_NETWORK_NO, rxBytes, 0L,
+                txBytes, 0L, 0L);
     }
 
     @Test
@@ -400,19 +413,16 @@ public class OffloadControllerTest {
         final OffloadController offload = makeOffloadController();
         offload.start();
 
+        final OffloadController.OffloadTetheringStatsProvider provider =
+                mTetherStatsProviderCaptor.getValue();
+
         final String ethernetIface = "eth1";
         final String mobileIface = "rmnet_data0";
 
-        ForwardedStats ethernetStats = new ForwardedStats();
-        ethernetStats.rxBytes = 12345;
-        ethernetStats.txBytes = 54321;
-
-        ForwardedStats mobileStats = new ForwardedStats();
-        mobileStats.rxBytes = 999;
-        mobileStats.txBytes = 99999;
-
-        when(mHardware.getForwardedStats(eq(ethernetIface))).thenReturn(ethernetStats);
-        when(mHardware.getForwardedStats(eq(mobileIface))).thenReturn(mobileStats);
+        when(mHardware.getForwardedStats(eq(ethernetIface))).thenReturn(
+                new ForwardedStats(12345, 54321));
+        when(mHardware.getForwardedStats(eq(mobileIface))).thenReturn(
+                new ForwardedStats(999, 99999));
 
         InOrder inOrder = inOrder(mHardware);
 
@@ -432,10 +442,35 @@ public class OffloadControllerTest {
         // Expect that we fetch stats from the previous upstream.
         inOrder.verify(mHardware, times(1)).getForwardedStats(eq(mobileIface));
 
-        ethernetStats = new ForwardedStats();
-        ethernetStats.rxBytes = 100000;
-        ethernetStats.txBytes = 100000;
-        when(mHardware.getForwardedStats(eq(ethernetIface))).thenReturn(ethernetStats);
+        // Verify that the fetched stats are stored.
+        final NetworkStats ifaceStats = provider.getTetherStats(STATS_PER_IFACE);
+        final NetworkStats uidStats = provider.getTetherStats(STATS_PER_UID);
+        final NetworkStats expectedIfaceStats = new NetworkStats(0L, 2)
+                .addValues(buildTestEntry(STATS_PER_IFACE, mobileIface, 999, 99999))
+                .addValues(buildTestEntry(STATS_PER_IFACE, ethernetIface, 12345, 54321));
+
+        final NetworkStats expectedUidStats = new NetworkStats(0L, 2)
+                .addValues(buildTestEntry(STATS_PER_UID, mobileIface, 999, 99999))
+                .addValues(buildTestEntry(STATS_PER_UID, ethernetIface, 12345, 54321));
+
+        assertTrue(orderInsensitiveEquals(expectedIfaceStats, ifaceStats));
+        assertTrue(orderInsensitiveEquals(expectedUidStats, uidStats));
+
+        final ArgumentCaptor<NetworkStats> ifaceStatsCaptor = ArgumentCaptor.forClass(
+                NetworkStats.class);
+        final ArgumentCaptor<NetworkStats> uidStatsCaptor = ArgumentCaptor.forClass(
+                NetworkStats.class);
+
+        // Force pushing stats update to verify the stats reported.
+        provider.pushTetherStats();
+        verify(mTetherStatsProviderCb, times(1)).onStatsUpdated(anyInt(),
+                ifaceStatsCaptor.capture(), uidStatsCaptor.capture());
+        assertTrue(orderInsensitiveEquals(expectedIfaceStats, ifaceStatsCaptor.getValue()));
+        assertTrue(orderInsensitiveEquals(expectedUidStats, uidStatsCaptor.getValue()));
+
+
+        when(mHardware.getForwardedStats(eq(ethernetIface))).thenReturn(
+                new ForwardedStats(100000, 100000));
         offload.setUpstreamLinkProperties(null);
         // Expect that we first clear the HAL's upstream parameters.
         inOrder.verify(mHardware, times(1)).setUpstreamParameters(
@@ -443,37 +478,38 @@ public class OffloadControllerTest {
         // Expect that we fetch stats from the previous upstream.
         inOrder.verify(mHardware, times(1)).getForwardedStats(eq(ethernetIface));
 
-        ITetheringStatsProvider provider = mTetherStatsProviderCaptor.getValue();
-        NetworkStats stats = provider.getTetherStats(STATS_PER_IFACE);
-        NetworkStats perUidStats = provider.getTetherStats(STATS_PER_UID);
-        waitForIdle();
         // There is no current upstream, so no stats are fetched.
         inOrder.verify(mHardware, never()).getForwardedStats(any());
         inOrder.verifyNoMoreInteractions();
 
-        assertEquals(2, stats.size());
-        assertEquals(2, perUidStats.size());
-
-        NetworkStats.Entry entry = null;
-        for (int i = 0; i < stats.size(); i++) {
-            assertEquals(UID_ALL, stats.getValues(i, entry).uid);
-            assertEquals(UID_TETHERING, perUidStats.getValues(i, entry).uid);
-        }
-
-        int ethernetPosition = ethernetIface.equals(stats.getValues(0, entry).iface) ? 0 : 1;
-        int mobilePosition = 1 - ethernetPosition;
-
-        entry = stats.getValues(mobilePosition, entry);
-        assertNetworkStats(mobileIface, mobileStats, entry);
-        entry = perUidStats.getValues(mobilePosition, entry);
-        assertNetworkStats(mobileIface, mobileStats, entry);
-
-        ethernetStats.rxBytes = 12345 + 100000;
-        ethernetStats.txBytes = 54321 + 100000;
-        entry = stats.getValues(ethernetPosition, entry);
-        assertNetworkStats(ethernetIface, ethernetStats, entry);
-        entry = perUidStats.getValues(ethernetPosition, entry);
-        assertNetworkStats(ethernetIface, ethernetStats, entry);
+        // Verify that the stored stats is accumulated.
+        final NetworkStats ifaceStatsAccu = provider.getTetherStats(STATS_PER_IFACE);
+        final NetworkStats uidStatsAccu = provider.getTetherStats(STATS_PER_UID);
+        final NetworkStats expectedIfaceStatsAccu = new NetworkStats(0L, 2)
+                .addValues(buildTestEntry(STATS_PER_IFACE, mobileIface, 999, 99999))
+                .addValues(buildTestEntry(STATS_PER_IFACE, ethernetIface, 112345, 154321));
+
+        final NetworkStats expectedUidStatsAccu = new NetworkStats(0L, 2)
+                .addValues(buildTestEntry(STATS_PER_UID, mobileIface, 999, 99999))
+                .addValues(buildTestEntry(STATS_PER_UID, ethernetIface, 112345, 154321));
+
+        assertTrue(orderInsensitiveEquals(expectedIfaceStatsAccu, ifaceStatsAccu));
+        assertTrue(orderInsensitiveEquals(expectedUidStatsAccu, uidStatsAccu));
+
+        // Verify that only diff of stats is reported.
+        reset(mTetherStatsProviderCb);
+        provider.pushTetherStats();
+        final NetworkStats expectedIfaceStatsDiff = new NetworkStats(0L, 2)
+                .addValues(buildTestEntry(STATS_PER_IFACE, mobileIface, 0, 0))
+                .addValues(buildTestEntry(STATS_PER_IFACE, ethernetIface, 100000, 100000));
+
+        final NetworkStats expectedUidStatsDiff = new NetworkStats(0L, 2)
+                .addValues(buildTestEntry(STATS_PER_UID, mobileIface, 0, 0))
+                .addValues(buildTestEntry(STATS_PER_UID, ethernetIface, 100000, 100000));
+        verify(mTetherStatsProviderCb, times(1)).onStatsUpdated(anyInt(),
+                ifaceStatsCaptor.capture(), uidStatsCaptor.capture());
+        assertTrue(orderInsensitiveEquals(expectedIfaceStatsDiff, ifaceStatsCaptor.getValue()));
+        assertTrue(orderInsensitiveEquals(expectedUidStatsDiff, uidStatsCaptor.getValue()));
     }
 
     @Test
@@ -493,19 +529,19 @@ public class OffloadControllerTest {
         lp.setInterfaceName(ethernetIface);
         offload.setUpstreamLinkProperties(lp);
 
-        ITetheringStatsProvider provider = mTetherStatsProviderCaptor.getValue();
+        AbstractNetworkStatsProvider provider = mTetherStatsProviderCaptor.getValue();
         final InOrder inOrder = inOrder(mHardware);
         when(mHardware.setUpstreamParameters(any(), any(), any(), any())).thenReturn(true);
         when(mHardware.setDataLimit(anyString(), anyLong())).thenReturn(true);
 
         // Applying an interface quota to the current upstream immediately sends it to the hardware.
-        provider.setInterfaceQuota(ethernetIface, ethernetLimit);
+        provider.setLimit(ethernetIface, ethernetLimit);
         waitForIdle();
         inOrder.verify(mHardware).setDataLimit(ethernetIface, ethernetLimit);
         inOrder.verifyNoMoreInteractions();
 
         // Applying an interface quota to another upstream does not take any immediate action.
-        provider.setInterfaceQuota(mobileIface, mobileLimit);
+        provider.setLimit(mobileIface, mobileLimit);
         waitForIdle();
         inOrder.verify(mHardware, never()).setDataLimit(anyString(), anyLong());
 
@@ -518,7 +554,7 @@ public class OffloadControllerTest {
 
         // Setting a limit of ITetheringStatsProvider.QUOTA_UNLIMITED causes the limit to be set
         // to Long.MAX_VALUE.
-        provider.setInterfaceQuota(mobileIface, ITetheringStatsProvider.QUOTA_UNLIMITED);
+        provider.setLimit(mobileIface, ITetheringStatsProvider.QUOTA_UNLIMITED);
         waitForIdle();
         inOrder.verify(mHardware).setDataLimit(mobileIface, Long.MAX_VALUE);
 
@@ -526,7 +562,7 @@ public class OffloadControllerTest {
         when(mHardware.setUpstreamParameters(any(), any(), any(), any())).thenReturn(false);
         lp.setInterfaceName(ethernetIface);
         offload.setUpstreamLinkProperties(lp);
-        provider.setInterfaceQuota(mobileIface, mobileLimit);
+        provider.setLimit(mobileIface, mobileLimit);
         waitForIdle();
         inOrder.verify(mHardware, never()).setDataLimit(anyString(), anyLong());
 
@@ -535,7 +571,7 @@ public class OffloadControllerTest {
         when(mHardware.setDataLimit(anyString(), anyLong())).thenReturn(false);
         lp.setInterfaceName(mobileIface);
         offload.setUpstreamLinkProperties(lp);
-        provider.setInterfaceQuota(mobileIface, mobileLimit);
+        provider.setLimit(mobileIface, mobileLimit);
         waitForIdle();
         inOrder.verify(mHardware).getForwardedStats(ethernetIface);
         inOrder.verify(mHardware).stopOffloadControl();
@@ -551,7 +587,7 @@ public class OffloadControllerTest {
 
         OffloadHardwareInterface.ControlCallback callback = mControlCallbackCaptor.getValue();
         callback.onStoppedLimitReached();
-        verify(mNMService, times(1)).tetherLimitReached(mTetherStatsProviderCaptor.getValue());
+        verify(mTetherStatsProviderCb, times(1)).onStatsUpdated(anyInt(), any(), any());
     }
 
     @Test
@@ -654,9 +690,10 @@ public class OffloadControllerTest {
         // Verify forwarded stats behaviour.
         verify(mHardware, times(1)).getForwardedStats(eq(RMNET0));
         verify(mHardware, times(1)).getForwardedStats(eq(WLAN0));
+        // TODO: verify the exact stats reported.
+        verify(mTetherStatsProviderCb, times(1)).onStatsUpdated(anyInt(), any(), any());
+        verifyNoMoreInteractions(mTetherStatsProviderCb);
         verifyNoMoreInteractions(mHardware);
-        verify(mNMService, times(1)).tetherLimitReached(mTetherStatsProviderCaptor.getValue());
-        verifyNoMoreInteractions(mNMService);
     }
 
     @Test
@@ -719,8 +756,8 @@ public class OffloadControllerTest {
         // Verify forwarded stats behaviour.
         verify(mHardware, times(1)).getForwardedStats(eq(RMNET0));
         verify(mHardware, times(1)).getForwardedStats(eq(WLAN0));
-        verify(mNMService, times(1)).tetherLimitReached(mTetherStatsProviderCaptor.getValue());
-        verifyNoMoreInteractions(mNMService);
+        verify(mTetherStatsProviderCb, times(1)).onStatsUpdated(anyInt(), any(), any());
+        verifyNoMoreInteractions(mTetherStatsProviderCb);
 
         // TODO: verify local prefixes and downstreams are also pushed to the HAL.
         verify(mHardware, times(1)).setLocalPrefixes(mStringArrayCaptor.capture());
diff --git a/packages/Tethering/tests/unit/src/com/android/server/connectivity/tethering/TetheringTest.java b/packages/Tethering/tests/unit/src/com/android/server/connectivity/tethering/TetheringTest.java
index 0df32fd9f35b..00afb9712097 100644
--- a/packages/Tethering/tests/unit/src/com/android/server/connectivity/tethering/TetheringTest.java
+++ b/packages/Tethering/tests/unit/src/com/android/server/connectivity/tethering/TetheringTest.java
@@ -457,7 +457,7 @@ public class TetheringTest {
         mServiceContext.registerReceiver(mBroadcastReceiver,
                 new IntentFilter(ACTION_TETHER_STATE_CHANGED));
         mTethering = makeTethering();
-        verify(mNMService).registerTetheringStatsProvider(any(), anyString());
+        verify(mStatsService, times(1)).registerNetworkStatsProvider(anyString(), any());
         verify(mNetd).registerUnsolicitedEventListener(any());
         final ArgumentCaptor<PhoneStateListener> phoneListenerCaptor =
                 ArgumentCaptor.forClass(PhoneStateListener.class);