diff --git a/TEST_MAPPING b/TEST_MAPPING
index 1e8babf..6e30fd1 100644
--- a/TEST_MAPPING
+++ b/TEST_MAPPING
@@ -205,6 +205,9 @@
     },
     {
       "path": "packages/modules/CaptivePortalLogin"
+    },
+    {
+      "path": "vendor/xts/gts-tests/hostsidetests/networkstack"
     }
   ]
 }
diff --git a/Tethering/tests/integration/src/android/net/EthernetTetheringTest.java b/Tethering/tests/integration/src/android/net/EthernetTetheringTest.java
index 880a285..9e6fc0b 100644
--- a/Tethering/tests/integration/src/android/net/EthernetTetheringTest.java
+++ b/Tethering/tests/integration/src/android/net/EthernetTetheringTest.java
@@ -139,6 +139,9 @@
     // Kernel treats a confirmed UDP connection which active after two seconds as stream mode.
     // See upstream commit b7b1d02fc43925a4d569ec221715db2dfa1ce4f5.
     private static final int UDP_STREAM_TS_MS = 2000;
+    // Give slack time for waiting UDP stream mode because handling conntrack event in user space
+    // may not in precise time. Used to reduce the flaky rate.
+    private static final int UDP_STREAM_SLACK_MS = 500;
     // Per RX UDP packet size: iphdr (20) + udphdr (8) + payload (2) = 30 bytes.
     private static final int RX_UDP_PACKET_SIZE = 30;
     private static final int RX_UDP_PACKET_COUNT = 456;
@@ -1171,6 +1174,9 @@
             Thread.sleep(UDP_STREAM_TS_MS);
             sendUploadPacketUdp(srcMac, dstMac, clientIp, remoteIp, tester, false /* is4To6 */);
 
+            // Give a slack time for handling conntrack event in user space.
+            Thread.sleep(UDP_STREAM_SLACK_MS);
+
             // [1] Verify IPv4 upstream rule map.
             final HashMap<Tether4Key, Tether4Value> upstreamMap = pollRawMapFromDump(
                     Tether4Key.class, Tether4Value.class, DUMPSYS_RAWMAP_ARG_UPSTREAM4);
@@ -1512,7 +1518,7 @@
         final TestDnsPacket dnsQuery = TestDnsPacket.getTestDnsPacket(buf);
         assertNotNull(dnsQuery);
         Log.d(TAG, "Forwarded UDP source port: " + udpHeader.srcPort + ", DNS query id: "
-                + dnsQuery.getHeader().id);
+                + dnsQuery.getHeader().getId());
 
         // [2] Send DNS reply.
         // DNS server --> upstream --> dnsmasq forwarding --> downstream --> tethered device
@@ -1522,7 +1528,7 @@
         final Inet4Address remoteIp = (Inet4Address) TEST_IP4_DNS;
         final Inet4Address tetheringUpstreamIp = (Inet4Address) TEST_IP4_ADDR.getAddress();
         sendDownloadPacketDnsV4(remoteIp, tetheringUpstreamIp, DNS_PORT,
-                (short) udpHeader.srcPort, (short) dnsQuery.getHeader().id, tester);
+                (short) udpHeader.srcPort, (short) dnsQuery.getHeader().getId(), tester);
     }
 
     private <T> List<T> toList(T... array) {
diff --git a/framework/api/current.txt b/framework/api/current.txt
index 547b7e2..09b4538 100644
--- a/framework/api/current.txt
+++ b/framework/api/current.txt
@@ -188,6 +188,7 @@
     field public static final int FLAG_NO_RETRY = 1; // 0x1
     field public static final int TYPE_A = 1; // 0x1
     field public static final int TYPE_AAAA = 28; // 0x1c
+    field public static final int TYPE_CNAME = 5; // 0x5
   }
 
   public static interface DnsResolver.Callback<T> {
diff --git a/framework/src/android/net/DnsResolver.java b/framework/src/android/net/DnsResolver.java
index 5e637f9..33722fc 100644
--- a/framework/src/android/net/DnsResolver.java
+++ b/framework/src/android/net/DnsResolver.java
@@ -71,12 +71,14 @@
 
     @IntDef(prefix = { "TYPE_" },  value = {
             TYPE_A,
-            TYPE_AAAA
+            TYPE_AAAA,
+            TYPE_CNAME
     })
     @Retention(RetentionPolicy.SOURCE)
     @interface QueryType {}
     public static final int TYPE_A = 1;
     public static final int TYPE_AAAA = 28;
+    public static final int TYPE_CNAME = 5;
 
     @IntDef(prefix = { "FLAG_" }, value = {
             FLAG_EMPTY,
@@ -542,7 +544,7 @@
 
         DnsAddressAnswer(@NonNull byte[] data) throws ParseException {
             super(data);
-            if ((mHeader.flags & (1 << 15)) == 0) {
+            if ((mHeader.getFlags() & (1 << 15)) == 0) {
                 throw new ParseException("Not an answer packet");
             }
             if (mHeader.getRecordCount(QDSECTION) == 0) {
diff --git a/service/src/com/android/server/ConnectivityService.java b/service/src/com/android/server/ConnectivityService.java
index afb3ca2..0035aa0 100755
--- a/service/src/com/android/server/ConnectivityService.java
+++ b/service/src/com/android/server/ConnectivityService.java
@@ -4579,7 +4579,7 @@
             if (req.isListen() || req.isListenForBest()) {
                 continue;
             }
-            // If this Network is already the highest scoring Network for a request, or if
+            // If this Network is already the best Network for a request, or if
             // there is hope for it to become one if it validated, then it is needed.
             if (candidate.satisfies(req)) {
                 // As soon as a network is found that satisfies a request, return. Specifically for
diff --git a/tests/cts/net/src/android/net/cts/DnsResolverTest.java b/tests/cts/net/src/android/net/cts/DnsResolverTest.java
index 0c53411..3821cea 100644
--- a/tests/cts/net/src/android/net/cts/DnsResolverTest.java
+++ b/tests/cts/net/src/android/net/cts/DnsResolverTest.java
@@ -200,13 +200,13 @@
             super(data);
 
             // Check QR field.(query (0), or a response (1)).
-            if ((mHeader.flags & (1 << 15)) == 0) {
+            if ((mHeader.getFlags() & (1 << 15)) == 0) {
                 throw new DnsParseException("Not an answer packet");
             }
         }
 
         int getRcode() {
-            return mHeader.rcode;
+            return mHeader.getFlags() & 0x0F;
         }
 
         int getANCount() {
diff --git a/tests/unit/java/com/android/server/net/NetworkStatsServiceTest.java b/tests/unit/java/com/android/server/net/NetworkStatsServiceTest.java
index 2febd2f..e053252 100644
--- a/tests/unit/java/com/android/server/net/NetworkStatsServiceTest.java
+++ b/tests/unit/java/com/android/server/net/NetworkStatsServiceTest.java
@@ -88,7 +88,6 @@
 import static org.mockito.Mockito.spy;
 import static org.mockito.Mockito.times;
 import static org.mockito.Mockito.verify;
-import static org.mockito.Mockito.when;
 
 import android.annotation.NonNull;
 import android.app.AlarmManager;
@@ -344,9 +343,9 @@
 
         final Context context = InstrumentationRegistry.getContext();
         mServiceContext = new MockContext(context);
-        when(mLocationPermissionChecker.checkCallersLocationPermission(
-                any(), any(), anyInt(), anyBoolean(), any())).thenReturn(true);
-        when(sWifiInfo.getNetworkKey()).thenReturn(TEST_WIFI_NETWORK_KEY);
+        doReturn(true).when(mLocationPermissionChecker).checkCallersLocationPermission(
+                any(), any(), anyInt(), anyBoolean(), any());
+        doReturn(TEST_WIFI_NETWORK_KEY).when(sWifiInfo).getNetworkKey();
         mStatsDir = TestIoUtils.createTemporaryDirectory(getClass().getSimpleName());
         mLegacyStatsDir = TestIoUtils.createTemporaryDirectory(
                 getClass().getSimpleName() + "-legacy");
@@ -1079,8 +1078,8 @@
 
     // TODO: support per IMSI state
     private void setMobileRatTypeAndWaitForIdle(int ratType) {
-        when(mNetworkStatsSubscriptionsMonitor.getRatTypeForSubscriberId(anyString()))
-                .thenReturn(ratType);
+        doReturn(ratType).when(mNetworkStatsSubscriptionsMonitor)
+                .getRatTypeForSubscriberId(anyString());
         mService.handleOnCollapsedRatTypeChanged();
         HandlerUtils.waitForIdle(mHandlerThread, WAIT_TIMEOUT);
     }
@@ -1524,8 +1523,8 @@
         mUsageCallback.expectOnThresholdReached(request);
 
         // Allow binder to disconnect
-        when(mUsageCallbackBinder.unlinkToDeath(any(IBinder.DeathRecipient.class), anyInt()))
-                .thenReturn(true);
+        doReturn(true).when(mUsageCallbackBinder)
+                .unlinkToDeath(any(IBinder.DeathRecipient.class), anyInt());
 
         // Unregister request
         mService.unregisterUsageRequest(request);
@@ -1707,7 +1706,7 @@
     }
 
     private void setCombineSubtypeEnabled(boolean enable) {
-        when(mSettings.getCombineSubtypeEnabled()).thenReturn(enable);
+        doReturn(enable).when(mSettings).getCombineSubtypeEnabled();
         mHandler.post(() -> mContentObserver.onChange(false, Settings.Global
                     .getUriFor(Settings.Global.NETSTATS_COMBINE_SUBTYPE_ENABLED)));
         waitForIdle();
@@ -1867,8 +1866,8 @@
      */
     @Test
     public void testEnforceTemplateLocationPermission() throws Exception {
-        when(mLocationPermissionChecker.checkCallersLocationPermission(
-                any(), any(), anyInt(), anyBoolean(), any())).thenReturn(false);
+        doReturn(false).when(mLocationPermissionChecker)
+                .checkCallersLocationPermission(any(), any(), anyInt(), anyBoolean(), any());
         initWifiStats(buildWifiState(true, TEST_IFACE, IMSI_1));
         assertThrows(SecurityException.class, () ->
                 assertNetworkTotal(sTemplateWifi, 0L, 0L, 0L, 0L, 0));
@@ -1876,8 +1875,8 @@
         assertNetworkTotal(sTemplateCarrierWifi1, 0L, 0L, 0L, 0L, 0);
         assertNetworkTotal(sTemplateImsi1, 0L, 0L, 0L, 0L, 0);
 
-        when(mLocationPermissionChecker.checkCallersLocationPermission(
-                any(), any(), anyInt(), anyBoolean(), any())).thenReturn(true);
+        doReturn(true).when(mLocationPermissionChecker)
+                .checkCallersLocationPermission(any(), any(), anyInt(), anyBoolean(), any());
         assertNetworkTotal(sTemplateCarrierWifi1, 0L, 0L, 0L, 0L, 0);
         assertNetworkTotal(sTemplateWifi, 0L, 0L, 0L, 0L, 0);
         assertNetworkTotal(sTemplateImsi1, 0L, 0L, 0L, 0L, 0);
@@ -2205,11 +2204,11 @@
     }
 
     private void mockNetworkStatsSummaryDev(NetworkStats summary) throws Exception {
-        when(mStatsFactory.readNetworkStatsSummaryDev()).thenReturn(summary);
+        doReturn(summary).when(mStatsFactory).readNetworkStatsSummaryDev();
     }
 
     private void mockNetworkStatsSummaryXt(NetworkStats summary) throws Exception {
-        when(mStatsFactory.readNetworkStatsSummaryXt()).thenReturn(summary);
+        doReturn(summary).when(mStatsFactory).readNetworkStatsSummaryXt();
     }
 
     private void mockNetworkStatsUidDetail(NetworkStats detail) throws Exception {
@@ -2219,11 +2218,11 @@
 
     private void mockNetworkStatsUidDetail(NetworkStats detail,
             TetherStatsParcel[] tetherStatsParcels) throws Exception {
-        when(mStatsFactory.readNetworkStatsDetail(UID_ALL, INTERFACES_ALL, TAG_ALL))
-                .thenReturn(detail);
+        doReturn(detail).when(mStatsFactory)
+                .readNetworkStatsDetail(UID_ALL, INTERFACES_ALL, TAG_ALL);
 
         // also include tethering details, since they are folded into UID
-        when(mNetd.tetherGetStats()).thenReturn(tetherStatsParcels);
+        doReturn(tetherStatsParcels).when(mNetd).tetherGetStats();
     }
 
     private void mockDefaultSettings() throws Exception {
@@ -2231,22 +2230,22 @@
     }
 
     private void mockSettings(long bucketDuration, long deleteAge) throws Exception {
-        when(mSettings.getPollInterval()).thenReturn(HOUR_IN_MILLIS);
-        when(mSettings.getPollDelay()).thenReturn(0L);
-        when(mSettings.getSampleEnabled()).thenReturn(true);
-        when(mSettings.getCombineSubtypeEnabled()).thenReturn(false);
+        doReturn(HOUR_IN_MILLIS).when(mSettings).getPollInterval();
+        doReturn(0L).when(mSettings).getPollDelay();
+        doReturn(true).when(mSettings).getSampleEnabled();
+        doReturn(false).when(mSettings).getCombineSubtypeEnabled();
 
         final Config config = new Config(bucketDuration, deleteAge, deleteAge);
-        when(mSettings.getDevConfig()).thenReturn(config);
-        when(mSettings.getXtConfig()).thenReturn(config);
-        when(mSettings.getUidConfig()).thenReturn(config);
-        when(mSettings.getUidTagConfig()).thenReturn(config);
+        doReturn(config).when(mSettings).getDevConfig();
+        doReturn(config).when(mSettings).getXtConfig();
+        doReturn(config).when(mSettings).getUidConfig();
+        doReturn(config).when(mSettings).getUidTagConfig();
 
-        when(mSettings.getGlobalAlertBytes(anyLong())).thenReturn(MB_IN_BYTES);
-        when(mSettings.getDevPersistBytes(anyLong())).thenReturn(MB_IN_BYTES);
-        when(mSettings.getXtPersistBytes(anyLong())).thenReturn(MB_IN_BYTES);
-        when(mSettings.getUidPersistBytes(anyLong())).thenReturn(MB_IN_BYTES);
-        when(mSettings.getUidTagPersistBytes(anyLong())).thenReturn(MB_IN_BYTES);
+        doReturn(MB_IN_BYTES).when(mSettings).getGlobalAlertBytes(anyLong());
+        doReturn(MB_IN_BYTES).when(mSettings).getDevPersistBytes(anyLong());
+        doReturn(MB_IN_BYTES).when(mSettings).getXtPersistBytes(anyLong());
+        doReturn(MB_IN_BYTES).when(mSettings).getUidPersistBytes(anyLong());
+        doReturn(MB_IN_BYTES).when(mSettings).getUidTagPersistBytes(anyLong());
     }
 
     private void assertStatsFilesExist(boolean exist) {