diff --git a/Tethering/tests/integration/src/android/net/EthernetTetheringTest.java b/Tethering/tests/integration/src/android/net/EthernetTetheringTest.java
index 92be84d..237a645 100644
--- a/Tethering/tests/integration/src/android/net/EthernetTetheringTest.java
+++ b/Tethering/tests/integration/src/android/net/EthernetTetheringTest.java
@@ -28,7 +28,6 @@
 import static android.net.TetheringManager.TETHERING_ETHERNET;
 import static android.net.TetheringTester.RemoteResponder;
 import static android.net.TetheringTester.isIcmpv6Type;
-import static android.system.OsConstants.IPPROTO_ICMPV6;
 import static android.system.OsConstants.IPPROTO_IP;
 import static android.system.OsConstants.IPPROTO_IPV6;
 import static android.system.OsConstants.IPPROTO_UDP;
@@ -85,7 +84,6 @@
 import com.android.net.module.util.bpf.TetherStatsKey;
 import com.android.net.module.util.bpf.TetherStatsValue;
 import com.android.net.module.util.structs.EthernetHeader;
-import com.android.net.module.util.structs.Icmpv6Header;
 import com.android.net.module.util.structs.Ipv4Header;
 import com.android.net.module.util.structs.Ipv6Header;
 import com.android.net.module.util.structs.UdpHeader;
@@ -146,6 +144,7 @@
     // Per TX UDP packet size: ethhdr (14) + iphdr (20) + udphdr (8) + payload (2) = 44 bytes.
     private static final int TX_UDP_PACKET_SIZE = 44;
     private static final int TX_UDP_PACKET_COUNT = 123;
+    private static final long WAIT_RA_TIMEOUT_MS = 2000;
 
     private static final LinkAddress TEST_IP4_ADDR = new LinkAddress("10.0.0.1/8");
     private static final LinkAddress TEST_IP6_ADDR = new LinkAddress("2001:db8:1::101/64");
@@ -329,27 +328,13 @@
 
     }
 
-    private static boolean isRouterAdvertisement(byte[] pkt) {
-        if (pkt == null) return false;
-
-        ByteBuffer buf = ByteBuffer.wrap(pkt);
-
-        final EthernetHeader ethHdr = Struct.parse(EthernetHeader.class, buf);
-        if (ethHdr.etherType != ETHER_TYPE_IPV6) return false;
-
-        final Ipv6Header ipv6Hdr = Struct.parse(Ipv6Header.class, buf);
-        if (ipv6Hdr.nextHeader != (byte) IPPROTO_ICMPV6) return false;
-
-        final Icmpv6Header icmpv6Hdr = Struct.parse(Icmpv6Header.class, buf);
-        return icmpv6Hdr.type == (short) ICMPV6_ROUTER_ADVERTISEMENT;
-    }
-
-    private static void expectRouterAdvertisement(TapPacketReader reader, String iface,
+    private static void waitForRouterAdvertisement(TapPacketReader reader, String iface,
             long timeoutMs) {
         final long deadline = SystemClock.uptimeMillis() + timeoutMs;
         do {
             byte[] pkt = reader.popPacket(timeoutMs);
-            if (isRouterAdvertisement(pkt)) return;
+            if (isIcmpv6Type(pkt, true /* hasEth */, ICMPV6_ROUTER_ADVERTISEMENT)) return;
+
             timeoutMs = deadline - SystemClock.uptimeMillis();
         } while (timeoutMs > 0);
         fail("Did not receive router advertisement on " + iface + " after "
@@ -401,7 +386,7 @@
         // before the reader is started.
         mDownstreamReader = makePacketReader(mDownstreamIface);
 
-        expectRouterAdvertisement(mDownstreamReader, iface, 2000 /* timeoutMs */);
+        waitForRouterAdvertisement(mDownstreamReader, iface, WAIT_RA_TIMEOUT_MS);
         expectLocalOnlyAddresses(iface);
     }
 
diff --git a/service/native/TrafficControllerTest.cpp b/service/native/TrafficControllerTest.cpp
index 1aca633..f63a3d9 100644
--- a/service/native/TrafficControllerTest.cpp
+++ b/service/native/TrafficControllerTest.cpp
@@ -790,6 +790,46 @@
     EXPECT_TRUE(expectDumpsysContains(expectedLines));
 }
 
+TEST_F(TrafficControllerTest, uidMatchTypeToString) {
+    // NO_MATCH(0) can't be verified because match type flag is added by OR operator.
+    // See TrafficController::addRule()
+    static const struct TestConfig {
+        UidOwnerMatchType uidOwnerMatchType;
+        std::string expected;
+    } testConfigs[] = {
+            // clang-format off
+            {HAPPY_BOX_MATCH, "HAPPY_BOX_MATCH"},
+            {DOZABLE_MATCH, "DOZABLE_MATCH"},
+            {STANDBY_MATCH, "STANDBY_MATCH"},
+            {POWERSAVE_MATCH, "POWERSAVE_MATCH"},
+            {HAPPY_BOX_MATCH, "HAPPY_BOX_MATCH"},
+            {RESTRICTED_MATCH, "RESTRICTED_MATCH"},
+            {LOW_POWER_STANDBY_MATCH, "LOW_POWER_STANDBY_MATCH"},
+            {IIF_MATCH, "IIF_MATCH"},
+            {LOCKDOWN_VPN_MATCH, "LOCKDOWN_VPN_MATCH"},
+            {OEM_DENY_1_MATCH, "OEM_DENY_1_MATCH"},
+            {OEM_DENY_2_MATCH, "OEM_DENY_2_MATCH"},
+            {OEM_DENY_3_MATCH, "OEM_DENY_3_MATCH"},
+            // clang-format on
+    };
+
+    for (const auto& config : testConfigs) {
+        SCOPED_TRACE(fmt::format("testConfig: [{}, {}]", config.uidOwnerMatchType,
+                     config.expected));
+
+        // Test private function uidMatchTypeToString() via dumpsys.
+        ASSERT_TRUE(isOk(updateUidOwnerMaps({TEST_UID}, config.uidOwnerMatchType,
+                                            TrafficController::IptOpInsert)));
+        std::vector<std::string> expectedLines;
+        expectedLines.emplace_back(fmt::format("{}  {}", TEST_UID, config.expected));
+        EXPECT_TRUE(expectDumpsysContains(expectedLines));
+
+        // Clean up the stubs.
+        ASSERT_TRUE(isOk(updateUidOwnerMaps({TEST_UID}, config.uidOwnerMatchType,
+                                            TrafficController::IptOpDelete)));
+    }
+}
+
 TEST_F(TrafficControllerTest, getFirewallType) {
     static const struct TestConfig {
         ChildChain childChain;
@@ -805,6 +845,7 @@
             {LOCKDOWN, DENYLIST},
             {OEM_DENY_1, DENYLIST},
             {OEM_DENY_2, DENYLIST},
+            {OEM_DENY_3, DENYLIST},
             {INVALID_CHAIN, DENYLIST},
             // clang-format on
     };
diff --git a/service/src/com/android/server/connectivity/ClatCoordinator.java b/service/src/com/android/server/connectivity/ClatCoordinator.java
index 8cefd47..ea89be6 100644
--- a/service/src/com/android/server/connectivity/ClatCoordinator.java
+++ b/service/src/com/android/server/connectivity/ClatCoordinator.java
@@ -498,6 +498,31 @@
         }
     }
 
+    private void maybeCleanUp(ParcelFileDescriptor tunFd, ParcelFileDescriptor readSock6,
+            ParcelFileDescriptor writeSock6) {
+        if (tunFd != null) {
+            try {
+                tunFd.close();
+            } catch (IOException e) {
+                Log.e(TAG, "Fail to close tun file descriptor " + e);
+            }
+        }
+        if (readSock6 != null) {
+            try {
+                readSock6.close();
+            } catch (IOException e) {
+                Log.e(TAG, "Fail to close read socket " + e);
+            }
+        }
+        if (writeSock6 != null) {
+            try {
+                writeSock6.close();
+            } catch (IOException e) {
+                Log.e(TAG, "Fail to close write socket " + e);
+            }
+        }
+    }
+
     /**
      * Start clatd for a given interface and NAT64 prefix.
      */
@@ -546,8 +571,15 @@
 
         // [3] Open, configure and bring up the tun interface.
         // Create the v4-... tun interface.
+
+        // Initialize all required file descriptors with null pointer. This makes the following
+        // error handling easier. Simply always call #maybeCleanUp for closing file descriptors,
+        // if any valid ones, in error handling.
+        ParcelFileDescriptor tunFd = null;
+        ParcelFileDescriptor readSock6 = null;
+        ParcelFileDescriptor writeSock6 = null;
+
         final String tunIface = CLAT_PREFIX + iface;
-        final ParcelFileDescriptor tunFd;
         try {
             tunFd = mDeps.adoptFd(mDeps.createTunInterface(tunIface));
         } catch (IOException e) {
@@ -556,7 +588,7 @@
 
         final int tunIfIndex = mDeps.getInterfaceIndex(tunIface);
         if (tunIfIndex == INVALID_IFINDEX) {
-            tunFd.close();
+            maybeCleanUp(tunFd, readSock6, writeSock6);
             throw new IOException("Fail to get interface index for interface " + tunIface);
         }
 
@@ -564,7 +596,7 @@
         try {
             mNetd.interfaceSetEnableIPv6(tunIface, false /* enabled */);
         } catch (RemoteException | ServiceSpecificException e) {
-            tunFd.close();
+            maybeCleanUp(tunFd, readSock6, writeSock6);
             Log.e(TAG, "Disable IPv6 on " + tunIface + " failed: " + e);
         }
 
@@ -575,19 +607,17 @@
             detectedMtu = mDeps.detectMtu(pfx96Str,
                 ByteBuffer.wrap(GOOGLE_DNS_4.getAddress()).getInt(), fwmark);
         } catch (IOException e) {
-            tunFd.close();
+            maybeCleanUp(tunFd, readSock6, writeSock6);
             throw new IOException("Detect MTU on " + tunIface + " failed: " + e);
         }
         final int mtu = adjustMtu(detectedMtu);
         Log.i(TAG, "ipv4 mtu is " + mtu);
 
-        // TODO: add setIptablesDropRule
-
         // Config tun interface mtu, address and bring up.
         try {
             mNetd.interfaceSetMtu(tunIface, mtu);
         } catch (RemoteException | ServiceSpecificException e) {
-            tunFd.close();
+            maybeCleanUp(tunFd, readSock6, writeSock6);
             throw new IOException("Set MTU " + mtu + " on " + tunIface + " failed: " + e);
         }
         final InterfaceConfigurationParcel ifConfig = new InterfaceConfigurationParcel();
@@ -599,14 +629,13 @@
         try {
             mNetd.interfaceSetCfg(ifConfig);
         } catch (RemoteException | ServiceSpecificException e) {
-            tunFd.close();
+            maybeCleanUp(tunFd, readSock6, writeSock6);
             throw new IOException("Setting IPv4 address to " + ifConfig.ipv4Addr + "/"
                     + ifConfig.prefixLength + " failed on " + ifConfig.ifName + ": " + e);
         }
 
         // [4] Open and configure local 464xlat read/write sockets.
         // Opens a packet socket to receive IPv6 packets in clatd.
-        final ParcelFileDescriptor readSock6;
         try {
             // Use a JNI call to get native file descriptor instead of Os.socket() because we would
             // like to use ParcelFileDescriptor to manage file descriptor. But ctor
@@ -614,27 +643,23 @@
             // descriptor to initialize ParcelFileDescriptor object instead.
             readSock6 = mDeps.adoptFd(mDeps.openPacketSocket());
         } catch (IOException e) {
-            tunFd.close();
+            maybeCleanUp(tunFd, readSock6, writeSock6);
             throw new IOException("Open packet socket failed: " + e);
         }
 
         // Opens a raw socket with a given fwmark to send IPv6 packets in clatd.
-        final ParcelFileDescriptor writeSock6;
         try {
             // Use a JNI call to get native file descriptor instead of Os.socket(). See above
             // reason why we use jniOpenPacketSocket6().
             writeSock6 = mDeps.adoptFd(mDeps.openRawSocket6(fwmark));
         } catch (IOException e) {
-            tunFd.close();
-            readSock6.close();
+            maybeCleanUp(tunFd, readSock6, writeSock6);
             throw new IOException("Open raw socket failed: " + e);
         }
 
         final int ifIndex = mDeps.getInterfaceIndex(iface);
         if (ifIndex == INVALID_IFINDEX) {
-            tunFd.close();
-            readSock6.close();
-            writeSock6.close();
+            maybeCleanUp(tunFd, readSock6, writeSock6);
             throw new IOException("Fail to get interface index for interface " + iface);
         }
 
@@ -642,9 +667,7 @@
         try {
             mDeps.addAnycastSetsockopt(writeSock6.getFileDescriptor(), v6Str, ifIndex);
         } catch (IOException e) {
-            tunFd.close();
-            readSock6.close();
-            writeSock6.close();
+            maybeCleanUp(tunFd, readSock6, writeSock6);
             throw new IOException("add anycast sockopt failed: " + e);
         }
 
@@ -653,9 +676,7 @@
         try {
             cookie = mDeps.tagSocketAsClat(writeSock6.getFileDescriptor());
         } catch (IOException e) {
-            tunFd.close();
-            readSock6.close();
-            writeSock6.close();
+            maybeCleanUp(tunFd, readSock6, writeSock6);
             throw new IOException("tag raw socket failed: " + e);
         }
 
@@ -663,9 +684,7 @@
         try {
             mDeps.configurePacketSocket(readSock6.getFileDescriptor(), v6Str, ifIndex);
         } catch (IOException e) {
-            tunFd.close();
-            readSock6.close();
-            writeSock6.close();
+            maybeCleanUp(tunFd, readSock6, writeSock6);
             throw new IOException("configure packet socket failed: " + e);
         }
 
@@ -679,9 +698,9 @@
             mDeps.untagSocket(cookie);
             throw new IOException("Error start clatd on " + iface + ": " + e);
         } finally {
-            tunFd.close();
-            readSock6.close();
-            writeSock6.close();
+            // The file descriptors have been duplicated (dup2) to clatd in native_startClatd().
+            // Close these file descriptor stubs which are unused anymore.
+            maybeCleanUp(tunFd, readSock6, writeSock6);
         }
 
         // [6] Initialize and store clatd tracker object.
diff --git a/tests/unit/java/com/android/server/connectivity/ClatCoordinatorTest.java b/tests/unit/java/com/android/server/connectivity/ClatCoordinatorTest.java
index 3047a16..8dfe924 100644
--- a/tests/unit/java/com/android/server/connectivity/ClatCoordinatorTest.java
+++ b/tests/unit/java/com/android/server/connectivity/ClatCoordinatorTest.java
@@ -37,6 +37,7 @@
 import static org.mockito.Mockito.clearInvocations;
 import static org.mockito.Mockito.eq;
 import static org.mockito.Mockito.inOrder;
+import static org.mockito.Mockito.never;
 import static org.mockito.Mockito.spy;
 import static org.mockito.Mockito.verify;
 
@@ -556,14 +557,28 @@
                 () -> coordinator.clatStart(BASE_IFACE, NETID, NAT64_IP_PREFIX));
     }
 
-    private void checkNotStartClat(final TestDependencies deps, final boolean verifyTunFd,
-            final boolean verifyPacketSockFd, final boolean verifyRawSockFd) throws Exception {
+    private void checkNotStartClat(final TestDependencies deps, final boolean needToCloseTunFd,
+            final boolean needToClosePacketSockFd, final boolean needToCloseRawSockFd)
+            throws Exception {
         // [1] Expect that modified TestDependencies can't start clatd.
+        // Use precise check to make sure that there is no unexpected file descriptor closing.
         clearInvocations(TUN_PFD, RAW_SOCK_PFD, PACKET_SOCK_PFD);
         assertNotStartClat(deps);
-        if (verifyTunFd) verify(TUN_PFD).close();
-        if (verifyPacketSockFd) verify(PACKET_SOCK_PFD).close();
-        if (verifyRawSockFd) verify(RAW_SOCK_PFD).close();
+        if (needToCloseTunFd) {
+            verify(TUN_PFD).close();
+        } else {
+            verify(TUN_PFD, never()).close();
+        }
+        if (needToClosePacketSockFd) {
+            verify(PACKET_SOCK_PFD).close();
+        } else {
+            verify(PACKET_SOCK_PFD, never()).close();
+        }
+        if (needToCloseRawSockFd) {
+            verify(RAW_SOCK_PFD).close();
+        } else {
+            verify(RAW_SOCK_PFD, never()).close();
+        }
 
         // [2] Expect that unmodified TestDependencies can start clatd.
         // Used to make sure that the above modified TestDependencies has really broken the
@@ -582,8 +597,8 @@
                 throw new IOException();
             }
         }
-        checkNotStartClat(new FailureDependencies(), false /* verifyTunFd */,
-                false /* verifyPacketSockFd */, false /* verifyRawSockFd */);
+        checkNotStartClat(new FailureDependencies(), false /* needToCloseTunFd */,
+                false /* needToClosePacketSockFd */, false /* needToCloseRawSockFd */);
     }
 
     @Test
@@ -595,8 +610,8 @@
                 throw new IOException();
             }
         }
-        checkNotStartClat(new FailureDependencies(), false /* verifyTunFd */,
-                false /* verifyPacketSockFd */, false /* verifyRawSockFd */);
+        checkNotStartClat(new FailureDependencies(), false /* needToCloseTunFd */,
+                false /* needToClosePacketSockFd */, false /* needToCloseRawSockFd */);
     }
 
     @Test
@@ -607,8 +622,8 @@
                 throw new IOException();
             }
         }
-        checkNotStartClat(new FailureDependencies(), false /* verifyTunFd */,
-                false /* verifyPacketSockFd */, false /* verifyRawSockFd */);
+        checkNotStartClat(new FailureDependencies(), false /* needToCloseTunFd */,
+                false /* needToClosePacketSockFd */, false /* needToCloseRawSockFd */);
     }
 
     @Test
@@ -620,8 +635,8 @@
                 throw new IOException();
             }
         }
-        checkNotStartClat(new FailureDependencies(), true /* verifyTunFd */,
-                false /* verifyPacketSockFd */, false /* verifyRawSockFd */);
+        checkNotStartClat(new FailureDependencies(), true /* needToCloseTunFd */,
+                false /* needToClosePacketSockFd */, false /* needToCloseRawSockFd */);
     }
 
     @Test
@@ -632,8 +647,8 @@
                 throw new IOException();
             }
         }
-        checkNotStartClat(new FailureDependencies(), true /* verifyTunFd */,
-                false /* verifyPacketSockFd */, false /* verifyRawSockFd */);
+        checkNotStartClat(new FailureDependencies(), true /* needToCloseTunFd */,
+                false /* needToClosePacketSockFd */, false /* needToCloseRawSockFd */);
     }
 
     @Test
@@ -644,8 +659,8 @@
                 throw new IOException();
             }
         }
-        checkNotStartClat(new FailureDependencies(), true /* verifyTunFd */,
-                true /* verifyPacketSockFd */, false /* verifyRawSockFd */);
+        checkNotStartClat(new FailureDependencies(), true /* needToCloseTunFd */,
+                true /* needToClosePacketSockFd */, false /* needToCloseRawSockFd */);
     }
 
     @Test
@@ -657,8 +672,8 @@
                 throw new IOException();
             }
         }
-        checkNotStartClat(new FailureDependencies(), true /* verifyTunFd */,
-                true /* verifyPacketSockFd */, true /* verifyRawSockFd */);
+        checkNotStartClat(new FailureDependencies(), true /* needToCloseTunFd */,
+                true /* needToClosePacketSockFd */, true /* needToCloseRawSockFd */);
     }
 
     @Test
@@ -669,8 +684,8 @@
                 throw new IOException();
             }
         }
-        checkNotStartClat(new FailureDependencies(), true /* verifyTunFd */,
-                true /* verifyPacketSockFd */, true /* verifyRawSockFd */);
+        checkNotStartClat(new FailureDependencies(), true /* needToCloseTunFd */,
+                true /* needToClosePacketSockFd */, true /* needToCloseRawSockFd */);
     }
 
     @Test
@@ -682,8 +697,8 @@
                 throw new IOException();
             }
         }
-        checkNotStartClat(new FailureDependencies(), true /* verifyTunFd */,
-                true /* verifyPacketSockFd */, true /* verifyRawSockFd */);
+        checkNotStartClat(new FailureDependencies(), true /* needToCloseTunFd */,
+                true /* needToClosePacketSockFd */, true /* needToCloseRawSockFd */);
     }
 
     @Test
@@ -697,7 +712,7 @@
                 throw new IOException();
             }
         }
-        checkNotStartClat(new FailureDependencies(), true /* verifyTunFd */,
-                true /* verifyPacketSockFd */, true /* verifyRawSockFd */);
+        checkNotStartClat(new FailureDependencies(), true /* needToCloseTunFd */,
+                true /* needToClosePacketSockFd */, true /* needToCloseRawSockFd */);
     }
 }