NetworkStatsService: Fix getDetailedUidStats to take VPNs into account.

This API is similar to one provided by NetworkStatsFactory with the
difference that NSS also migrates traffic from VPN UID to other apps.

Since traffic can only be migrated over NetworkStats delta, NSS
therefore maintains NetworkStats snapshot across all UIDs/ifaces/tags.

This snapshot gets updated whenever NSS records a new snapshot
(based on various hooks such as VPN updating its underlying networks,
network getting lost, etc.), or getDetailedUidStats API is invoked by
one of its callers.

Bug: 113122541
Bug: 120145746
Test: atest FrameworksNetTests
Test: manually verified that battery stats are migrating traffic off of
TUN (after patching above CL where we point BatteryStats to use this
API).
Change-Id: Ib0f0c2d4d41ee1d7a027ea9da457baaf198d649e

tests/net/java/android/net/NetworkStatsTest.java

@@ -812,6 +812,37 @@ public class NetworkStatsTest {
         assertEquals(entry2, stats.getValues(1, null));
     }
 
+    @Test
+    public void testFilterDebugEntries() {
+        NetworkStats.Entry entry1 = new NetworkStats.Entry(
+                "test1", 10100, SET_DEFAULT, TAG_NONE, METERED_NO, ROAMING_NO,
+                DEFAULT_NETWORK_NO, 50000L, 25L, 100000L, 50L, 0L);
+
+        NetworkStats.Entry entry2 = new NetworkStats.Entry(
+                "test2", 10101, SET_DBG_VPN_IN, TAG_NONE, METERED_NO, ROAMING_NO,
+                DEFAULT_NETWORK_NO, 50000L, 25L, 100000L, 50L, 0L);
+
+        NetworkStats.Entry entry3 = new NetworkStats.Entry(
+                "test2", 10101, SET_DEFAULT, TAG_NONE, METERED_NO, ROAMING_NO,
+                DEFAULT_NETWORK_NO, 50000L, 25L, 100000L, 50L, 0L);
+
+        NetworkStats.Entry entry4 = new NetworkStats.Entry(
+                "test2", 10101, SET_DBG_VPN_OUT, TAG_NONE, METERED_NO, ROAMING_NO,
+                DEFAULT_NETWORK_NO, 50000L, 25L, 100000L, 50L, 0L);
+
+        NetworkStats stats = new NetworkStats(TEST_START, 4)
+                .addValues(entry1)
+                .addValues(entry2)
+                .addValues(entry3)
+                .addValues(entry4);
+
+        stats.filterDebugEntries();
+
+        assertEquals(2, stats.size());
+        assertEquals(entry1, stats.getValues(0, null));
+        assertEquals(entry3, stats.getValues(1, null));
+    }
+
     @Test
     public void testApply464xlatAdjustments() {
         final String v4Iface = "v4-wlan0";

tests/net/java/com/android/server/net/NetworkStatsServiceTest.java

@@ -57,6 +57,7 @@ import static com.android.server.net.NetworkStatsService.ACTION_NETWORK_STATS_PO
 
 import static org.junit.Assert.assertEquals;
 import static org.junit.Assert.assertNotNull;
+import static org.junit.Assert.assertNull;
 import static org.junit.Assert.assertTrue;
 import static org.mockito.ArgumentMatchers.any;
 import static org.mockito.ArgumentMatchers.anyInt;
@@ -216,11 +217,16 @@ public class NetworkStatsServiceTest {
         expectNetworkStatsUidDetail(buildEmptyStats());
         expectSystemReady();
 
+        assertNull(mService.getTunAdjustedStats());
         mService.systemReady();
+        // Verify that system ready fetches realtime stats and initializes tun adjusted stats.
+        verify(mNetManager).getNetworkStatsUidDetail(UID_ALL, INTERFACES_ALL);
+        assertNotNull("failed to initialize TUN adjusted stats", mService.getTunAdjustedStats());
+        assertEquals(0, mService.getTunAdjustedStats().size());
+
         mSession = mService.openSession();
         assertNotNull("openSession() failed", mSession);
 
-
         // catch INetworkManagementEventObserver during systemReady()
         ArgumentCaptor<INetworkManagementEventObserver> networkObserver =
               ArgumentCaptor.forClass(INetworkManagementEventObserver.class);
@@ -733,11 +739,13 @@ public class NetworkStatsServiceTest {
 
         NetworkStats stats = mService.getDetailedUidStats(ifaceFilter);
 
-        verify(mNetManager, times(1)).getNetworkStatsUidDetail(eq(UID_ALL), argThat(ifaces ->
+        // mNetManager#getNetworkStatsUidDetail(UID_ALL, INTERFACES_ALL) has following invocations:
-                ifaces != null && ifaces.length == 2
+        // 1) NetworkStatsService#systemReady from #setUp.
-                        && ArrayUtils.contains(ifaces, TEST_IFACE)
+        // 2) mService#forceUpdateIfaces in the test above.
-                        && ArrayUtils.contains(ifaces, stackedIface)));
+        // 3) Finally, mService#getDetailedUidStats.
-
+        verify(mNetManager, times(3)).getNetworkStatsUidDetail(UID_ALL, INTERFACES_ALL);
+        assertTrue(ArrayUtils.contains(stats.getUniqueIfaces(), TEST_IFACE));
+        assertTrue(ArrayUtils.contains(stats.getUniqueIfaces(), stackedIface));
         assertEquals(2, stats.size());
         assertEquals(uidStats, stats.getValues(0, null));
         assertEquals(tetheredStats1, stats.getValues(1, null));
@@ -1157,6 +1165,134 @@ public class NetworkStatsServiceTest {
         assertUidTotal(buildTemplateMobileWildcard(), UID_VPN, 1100L, 100L, 1100L, 100L, 1);
     }
 
+    @Test
+    public void recordSnapshot_migratesTunTrafficAndUpdatesTunAdjustedStats() throws Exception {
+        assertEquals(0, mService.getTunAdjustedStats().size());
+        // VPN using WiFi (TEST_IFACE).
+        VpnInfo[] vpnInfos = new VpnInfo[] {createVpnInfo(new String[] {TEST_IFACE})};
+        expectBandwidthControlCheck();
+        // create some traffic (assume 10 bytes of MTU for VPN interface and 1 byte encryption
+        // overhead per packet):
+        // 1000 bytes (100 packets) were downloaded by UID_RED over VPN.
+        // VPN received 1100 bytes (100 packets) over WiFi.
+        incrementCurrentTime(HOUR_IN_MILLIS);
+        expectNetworkStatsUidDetail(new NetworkStats(getElapsedRealtime(), 2)
+              .addValues(TUN_IFACE, UID_RED, SET_DEFAULT, TAG_NONE, 1000L, 100L, 0L, 0L, 0L)
+              .addValues(TEST_IFACE, UID_VPN, SET_DEFAULT, TAG_NONE, 1100L, 100L, 0L, 0L, 0L));
+
+        // this should lead to NSS#recordSnapshotLocked
+        mService.forceUpdateIfaces(
+                new Network[0], vpnInfos, new NetworkState[0], null /* activeIface */);
+
+        // Verify TUN adjusted stats have traffic migrated correctly.
+        // Of 1100 bytes VPN received over WiFi, expect 1000 bytes attributed to UID_RED and 100
+        // bytes attributed to UID_VPN.
+        NetworkStats tunAdjStats = mService.getTunAdjustedStats();
+        assertValues(
+                tunAdjStats, TEST_IFACE, UID_RED, SET_ALL, TAG_NONE, METERED_ALL, ROAMING_ALL,
+                DEFAULT_NETWORK_ALL, 1000L, 100L, 0L, 0L, 0);
+        assertValues(
+                tunAdjStats, TEST_IFACE, UID_VPN, SET_ALL, TAG_NONE, METERED_ALL, ROAMING_ALL,
+                DEFAULT_NETWORK_ALL, 100L, 0L, 0L, 0L, 0);
+    }
+
+    @Test
+    public void getDetailedUidStats_migratesTunTrafficAndUpdatesTunAdjustedStats()
+            throws Exception {
+        assertEquals(0, mService.getTunAdjustedStats().size());
+        // VPN using WiFi (TEST_IFACE).
+        VpnInfo[] vpnInfos = new VpnInfo[] {createVpnInfo(new String[] {TEST_IFACE})};
+        expectBandwidthControlCheck();
+        mService.forceUpdateIfaces(
+                new Network[0], vpnInfos, new NetworkState[0], null /* activeIface */);
+        // create some traffic (assume 10 bytes of MTU for VPN interface and 1 byte encryption
+        // overhead per packet):
+        // 1000 bytes (100 packets) were downloaded by UID_RED over VPN.
+        // VPN received 1100 bytes (100 packets) over WiFi.
+        incrementCurrentTime(HOUR_IN_MILLIS);
+        expectNetworkStatsUidDetail(new NetworkStats(getElapsedRealtime(), 2)
+              .addValues(TUN_IFACE, UID_RED, SET_DEFAULT, TAG_NONE, 1000L, 100L, 0L, 0L, 0L)
+              .addValues(TEST_IFACE, UID_VPN, SET_DEFAULT, TAG_NONE, 1100L, 100L, 0L, 0L, 0L));
+
+        mService.getDetailedUidStats(INTERFACES_ALL);
+
+        // Verify internally maintained TUN adjusted stats
+        NetworkStats tunAdjStats = mService.getTunAdjustedStats();
+        // Verify stats for TEST_IFACE (WiFi):
+        // Of 1100 bytes VPN received over WiFi, expect 1000 bytes attributed to UID_RED and 100
+        // bytes attributed to UID_VPN.
+        assertValues(
+                tunAdjStats, TEST_IFACE, UID_RED, SET_ALL, TAG_NONE, METERED_ALL, ROAMING_ALL,
+                DEFAULT_NETWORK_ALL, 1000L, 100L, 0L, 0L, 0);
+        assertValues(
+                tunAdjStats, TEST_IFACE, UID_VPN, SET_ALL, TAG_NONE, METERED_ALL, ROAMING_ALL,
+                DEFAULT_NETWORK_ALL, 100L, 0L, 0L, 0L, 0);
+        // Verify stats for TUN_IFACE; only UID_RED should have usage on it.
+        assertValues(
+                tunAdjStats, TUN_IFACE, UID_RED, SET_ALL, TAG_NONE, METERED_ALL, ROAMING_ALL,
+                DEFAULT_NETWORK_ALL, 1000L, 100L, 0L, 0L, 0);
+        assertValues(
+                tunAdjStats, TUN_IFACE, UID_VPN, SET_ALL, TAG_NONE, METERED_ALL, ROAMING_ALL,
+                DEFAULT_NETWORK_ALL, 0L, 0L, 0L, 0L, 0);
+
+        // lets assume that since last time, VPN received another 1100 bytes (same assumptions as
+        // before i.e. UID_RED downloaded another 1000 bytes).
+        incrementCurrentTime(HOUR_IN_MILLIS);
+        // Note - NetworkStatsFactory returns counters that are monotonically increasing.
+        expectNetworkStatsUidDetail(new NetworkStats(getElapsedRealtime(), 2)
+              .addValues(TUN_IFACE, UID_RED, SET_DEFAULT, TAG_NONE, 2000L, 200L, 0L, 0L, 0L)
+              .addValues(TEST_IFACE, UID_VPN, SET_DEFAULT, TAG_NONE, 2200L, 200L, 0L, 0L, 0L));
+
+        mService.getDetailedUidStats(INTERFACES_ALL);
+
+        tunAdjStats = mService.getTunAdjustedStats();
+        // verify TEST_IFACE stats:
+        assertValues(
+                tunAdjStats, TEST_IFACE, UID_RED, SET_ALL, TAG_NONE, METERED_ALL, ROAMING_ALL,
+                DEFAULT_NETWORK_ALL, 2000L, 200L, 0L, 0L, 0);
+        assertValues(
+                tunAdjStats, TEST_IFACE, UID_VPN, SET_ALL, TAG_NONE, METERED_ALL, ROAMING_ALL,
+                DEFAULT_NETWORK_ALL, 200L, 0L, 0L, 0L, 0);
+        // verify TUN_IFACE stats:
+        assertValues(
+                tunAdjStats, TUN_IFACE, UID_RED, SET_ALL, TAG_NONE, METERED_ALL, ROAMING_ALL,
+                DEFAULT_NETWORK_ALL, 2000L, 200L, 0L, 0L, 0);
+        assertValues(
+                tunAdjStats, TUN_IFACE, UID_VPN, SET_ALL, TAG_NONE, METERED_ALL, ROAMING_ALL,
+                DEFAULT_NETWORK_ALL, 0L, 0L, 0L, 0L, 0);
+    }
+
+    @Test
+    public void getDetailedUidStats_returnsCorrectStatsWithVpnRunning() throws Exception {
+        // VPN using WiFi (TEST_IFACE).
+        VpnInfo[] vpnInfos = new VpnInfo[] {createVpnInfo(new String[] {TEST_IFACE})};
+        expectBandwidthControlCheck();
+        mService.forceUpdateIfaces(
+                new Network[0], vpnInfos, new NetworkState[0], null /* activeIface */);
+        // create some traffic (assume 10 bytes of MTU for VPN interface and 1 byte encryption
+        // overhead per packet):
+        // 1000 bytes (100 packets) were downloaded by UID_RED over VPN.
+        // VPN received 1100 bytes (100 packets) over WiFi.
+        incrementCurrentTime(HOUR_IN_MILLIS);
+        expectNetworkStatsUidDetail(new NetworkStats(getElapsedRealtime(), 2)
+              .addValues(TUN_IFACE, UID_RED, SET_DEFAULT, TAG_NONE, 1000L, 100L, 0L, 0L, 0L)
+              .addValues(TEST_IFACE, UID_VPN, SET_DEFAULT, TAG_NONE, 1100L, 100L, 0L, 0L, 0L));
+
+        // Query realtime stats for TEST_IFACE.
+        NetworkStats queriedStats =
+                mService.getDetailedUidStats(new String[] {TEST_IFACE});
+
+        assertEquals(HOUR_IN_MILLIS, queriedStats.getElapsedRealtime());
+        // verify that returned stats are only for TEST_IFACE and VPN traffic is migrated correctly.
+        assertEquals(new String[] {TEST_IFACE}, queriedStats.getUniqueIfaces());
+        assertValues(
+                queriedStats, TEST_IFACE, UID_RED, SET_ALL, TAG_NONE, METERED_ALL, ROAMING_ALL,
+                DEFAULT_NETWORK_ALL, 1000L, 100L, 0L, 0L, 0);
+        assertValues(
+                queriedStats, TEST_IFACE, UID_VPN, SET_ALL, TAG_NONE, METERED_ALL, ROAMING_ALL,
+                DEFAULT_NETWORK_ALL, 100L, 0L, 0L, 0L, 0);
+    }
+
     @Test
     public void testRegisterUsageCallback() throws Exception {
         // pretend that wifi network comes online; service should ask about full