diff --git a/Tethering/src/com/android/networkstack/tethering/PrivateAddressCoordinator.java b/Tethering/src/com/android/networkstack/tethering/PrivateAddressCoordinator.java
index cc2422f..41a10ae 100644
--- a/Tethering/src/com/android/networkstack/tethering/PrivateAddressCoordinator.java
+++ b/Tethering/src/com/android/networkstack/tethering/PrivateAddressCoordinator.java
@@ -172,6 +172,9 @@
             return new LinkAddress(LEGACY_WIFI_P2P_IFACE_ADDRESS);
         }
 
+        // This ensures that tethering isn't started on 2 different interfaces with the same type.
+        // Once tethering could support multiple interface with the same type,
+        // TetheringSoftApCallback would need to handle it among others.
         final LinkAddress cachedAddress = mCachedAddresses.get(ipServer.interfaceType());
         if (useLastAddress && cachedAddress != null
                 && !isConflictWithUpstream(asIpPrefix(cachedAddress))) {
diff --git a/Tethering/src/com/android/networkstack/tethering/Tethering.java b/Tethering/src/com/android/networkstack/tethering/Tethering.java
index 551fd63..af017f3 100644
--- a/Tethering/src/com/android/networkstack/tethering/Tethering.java
+++ b/Tethering/src/com/android/networkstack/tethering/Tethering.java
@@ -448,8 +448,22 @@
                 mStateReceiver, noUpstreamFilter, PERMISSION_MAINLINE_NETWORK_STACK, mHandler);
 
         final WifiManager wifiManager = getWifiManager();
+        TetheringSoftApCallback softApCallback = new TetheringSoftApCallback();
         if (wifiManager != null) {
-            wifiManager.registerSoftApCallback(mExecutor, new TetheringSoftApCallback());
+            wifiManager.registerSoftApCallback(mExecutor, softApCallback);
+        }
+        if (SdkLevel.isAtLeastT() && wifiManager != null) {
+            try {
+                // Although WifiManager#registerLocalOnlyHotspotSoftApCallback document that it need
+                // NEARBY_WIFI_DEVICES permission, but actually a caller who have NETWORK_STACK
+                // or MAINLINE_NETWORK_STACK permission would also able to use this API.
+                wifiManager.registerLocalOnlyHotspotSoftApCallback(mExecutor, softApCallback);
+            } catch (UnsupportedOperationException e) {
+                // Since wifi module development in internal branch,
+                // #registerLocalOnlyHotspotSoftApCallback currently doesn't supported in AOSP
+                // before AOSP switch to Android T + 1.
+                Log.wtf(TAG, "registerLocalOnlyHotspotSoftApCallback API is not supported");
+            }
         }
 
         startTrackDefaultNetwork();
@@ -545,6 +559,13 @@
         }
 
         // Called by wifi when the number of soft AP clients changed.
+        // Currently multiple softAp would not behave well in PrivateAddressCoordinator
+        // (where it gets the address from cache), it ensure tethering only support one ipServer for
+        // TETHERING_WIFI. Once tethering support multiple softAp enabled simultaneously,
+        // onConnectedClientsChanged should also be updated to support tracking different softAp's
+        // clients individually.
+        // TODO: Add wtf log and have check to reject request duplicated type with different
+        // interface.
         @Override
         public void onConnectedClientsChanged(final List<WifiClient> clients) {
             updateConnectedClients(clients);
@@ -1297,7 +1318,7 @@
 
             // Finally bring up serving on the new interface
             mWifiP2pTetherInterface = group.getInterface();
-            enableWifiIpServing(mWifiP2pTetherInterface, IFACE_IP_MODE_LOCAL_ONLY);
+            enableWifiP2pIpServing(mWifiP2pTetherInterface);
         }
 
         private void handleUserRestrictionAction() {
@@ -1388,20 +1409,22 @@
         changeInterfaceState(ifname, ipServingMode);
     }
 
-    private void disableWifiIpServingCommon(int tetheringType, String ifname, int apState) {
-        mLog.log("Canceling WiFi tethering request -"
-                + " type=" + tetheringType
-                + " interface=" + ifname
-                + " state=" + apState);
-
-        if (!TextUtils.isEmpty(ifname)) {
-            final TetherState ts = mTetherStates.get(ifname);
-            if (ts != null) {
-                ts.ipServer.unwanted();
-                return;
-            }
+    private void disableWifiIpServingCommon(int tetheringType, String ifname) {
+        if (!TextUtils.isEmpty(ifname) && mTetherStates.containsKey(ifname)) {
+            mTetherStates.get(ifname).ipServer.unwanted();
+            return;
         }
 
+        if (SdkLevel.isAtLeastT()) {
+            mLog.e("Tethering no longer handle untracked interface after T: " + ifname);
+            return;
+        }
+
+        // Attempt to guess the interface name before T. Pure AOSP code should never enter here
+        // because WIFI_AP_STATE_CHANGED intent always include ifname and it should be tracked
+        // by mTetherStates. In case OEMs have some modification in wifi side which pass null
+        // or empty ifname. Before T, tethering allow to disable the first wifi ipServer if
+        // given ifname don't match any tracking ipServer.
         for (int i = 0; i < mTetherStates.size(); i++) {
             final IpServer ipServer = mTetherStates.valueAt(i).ipServer;
             if (ipServer.interfaceType() == tetheringType) {
@@ -1409,7 +1432,6 @@
                 return;
             }
         }
-
         mLog.log("Error disabling Wi-Fi IP serving; "
                 + (TextUtils.isEmpty(ifname) ? "no interface name specified"
                                            : "specified interface: " + ifname));
@@ -1418,20 +1440,39 @@
     private void disableWifiIpServing(String ifname, int apState) {
         // Regardless of whether we requested this transition, the AP has gone
         // down.  Don't try to tether again unless we're requested to do so.
-        // TODO: Remove this altogether, once Wi-Fi reliably gives us an
-        // interface name with every broadcast.
         mWifiTetherRequested = false;
 
-        disableWifiIpServingCommon(TETHERING_WIFI, ifname, apState);
+        mLog.log("Canceling WiFi tethering request - interface=" + ifname + " state=" + apState);
+
+        disableWifiIpServingCommon(TETHERING_WIFI, ifname);
+    }
+
+    private void enableWifiP2pIpServing(String ifname) {
+        if (TextUtils.isEmpty(ifname)) {
+            mLog.e("Cannot enable P2P IP serving with invalid interface");
+            return;
+        }
+
+        // After T, tethering always trust the iface pass by state change intent. This allow
+        // tethering to deprecate tetherable p2p regexs after T.
+        final int type = SdkLevel.isAtLeastT() ? TETHERING_WIFI_P2P : ifaceNameToType(ifname);
+        if (!checkTetherableType(type)) {
+            mLog.e(ifname + " is not a tetherable iface, ignoring");
+            return;
+        }
+        enableIpServing(type, ifname, IpServer.STATE_LOCAL_ONLY);
     }
 
     private void disableWifiP2pIpServingIfNeeded(String ifname) {
         if (TextUtils.isEmpty(ifname)) return;
 
-        disableWifiIpServingCommon(TETHERING_WIFI_P2P, ifname, /* fake */ 0);
+        mLog.log("Canceling P2P tethering request - interface=" + ifname);
+        disableWifiIpServingCommon(TETHERING_WIFI_P2P, ifname);
     }
 
     private void enableWifiIpServing(String ifname, int wifiIpMode) {
+        mLog.log("request WiFi tethering - interface=" + ifname + " state=" + wifiIpMode);
+
         // Map wifiIpMode values to IpServer.Callback serving states, inferring
         // from mWifiTetherRequested as a final "best guess".
         final int ipServingMode;
@@ -1447,13 +1488,18 @@
                 return;
         }
 
+        // After T, tethering always trust the iface pass by state change intent. This allow
+        // tethering to deprecate tetherable wifi regexs after T.
+        final int type = SdkLevel.isAtLeastT() ? TETHERING_WIFI : ifaceNameToType(ifname);
+        if (!checkTetherableType(type)) {
+            mLog.e(ifname + " is not a tetherable iface, ignoring");
+            return;
+        }
+
         if (!TextUtils.isEmpty(ifname)) {
-            ensureIpServerStarted(ifname);
-            changeInterfaceState(ifname, ipServingMode);
+            enableIpServing(type, ifname, ipServingMode);
         } else {
-            mLog.e(String.format(
-                    "Cannot enable IP serving in mode %s on missing interface name",
-                    ipServingMode));
+            mLog.e("Cannot enable IP serving on missing interface name");
         }
     }
 
@@ -2724,23 +2770,28 @@
         mTetherMainSM.sendMessage(which, state, 0, newLp);
     }
 
+    private boolean hasSystemFeature(final String feature) {
+        return mContext.getPackageManager().hasSystemFeature(feature);
+    }
+
+    private boolean checkTetherableType(int type) {
+        if ((type == TETHERING_WIFI || type == TETHERING_WIGIG)
+                && !hasSystemFeature(PackageManager.FEATURE_WIFI)) {
+            return false;
+        }
+
+        if (type == TETHERING_WIFI_P2P && !hasSystemFeature(PackageManager.FEATURE_WIFI_DIRECT)) {
+            return false;
+        }
+
+        return type != TETHERING_INVALID;
+    }
+
     private void ensureIpServerStarted(final String iface) {
         // If we don't care about this type of interface, ignore.
         final int interfaceType = ifaceNameToType(iface);
-        if (interfaceType == TETHERING_INVALID) {
-            mLog.log(iface + " is not a tetherable iface, ignoring");
-            return;
-        }
-
-        final PackageManager pm = mContext.getPackageManager();
-        if ((interfaceType == TETHERING_WIFI || interfaceType == TETHERING_WIGIG)
-                && !pm.hasSystemFeature(PackageManager.FEATURE_WIFI)) {
-            mLog.log(iface + " is not tetherable, because WiFi feature is disabled");
-            return;
-        }
-        if (interfaceType == TETHERING_WIFI_P2P
-                && !pm.hasSystemFeature(PackageManager.FEATURE_WIFI_DIRECT)) {
-            mLog.log(iface + " is not tetherable, because WiFi Direct feature is disabled");
+        if (!checkTetherableType(interfaceType)) {
+            mLog.log(iface + " is used for " + interfaceType + " which is not tetherable");
             return;
         }
 
diff --git a/Tethering/tests/unit/src/com/android/networkstack/tethering/TetheringTest.java b/Tethering/tests/unit/src/com/android/networkstack/tethering/TetheringTest.java
index 4662c96..80666e6 100644
--- a/Tethering/tests/unit/src/com/android/networkstack/tethering/TetheringTest.java
+++ b/Tethering/tests/unit/src/com/android/networkstack/tethering/TetheringTest.java
@@ -58,6 +58,7 @@
 import static android.net.wifi.WifiManager.EXTRA_WIFI_AP_STATE;
 import static android.net.wifi.WifiManager.IFACE_IP_MODE_LOCAL_ONLY;
 import static android.net.wifi.WifiManager.IFACE_IP_MODE_TETHERED;
+import static android.net.wifi.WifiManager.WIFI_AP_STATE_DISABLED;
 import static android.net.wifi.WifiManager.WIFI_AP_STATE_ENABLED;
 import static android.system.OsConstants.RT_SCOPE_UNIVERSE;
 import static android.telephony.SubscriptionManager.INVALID_SUBSCRIPTION_ID;
@@ -194,6 +195,7 @@
 import com.android.networkstack.apishim.common.UnsupportedApiLevelException;
 import com.android.networkstack.tethering.TestConnectivityManager.TestNetworkAgent;
 import com.android.networkstack.tethering.metrics.TetheringMetrics;
+import com.android.testutils.DevSdkIgnoreRule.IgnoreUpTo;
 import com.android.testutils.MiscAsserts;
 
 import org.junit.After;
@@ -300,6 +302,7 @@
     private OffloadController mOffloadCtrl;
     private PrivateAddressCoordinator mPrivateAddressCoordinator;
     private SoftApCallback mSoftApCallback;
+    private SoftApCallback mLocalOnlyHotspotCallback;
     private UpstreamNetworkMonitor mUpstreamNetworkMonitor;
     private TetheredInterfaceCallbackShim mTetheredInterfaceCallbackShim;
 
@@ -670,6 +673,14 @@
         verify(mWifiManager).registerSoftApCallback(any(), softApCallbackCaptor.capture());
         mSoftApCallback = softApCallbackCaptor.getValue();
 
+        if (isAtLeastT()) {
+            final ArgumentCaptor<SoftApCallback> localOnlyCallbackCaptor =
+                    ArgumentCaptor.forClass(SoftApCallback.class);
+            verify(mWifiManager).registerLocalOnlyHotspotSoftApCallback(any(),
+                    localOnlyCallbackCaptor.capture());
+            mLocalOnlyHotspotCallback = localOnlyCallbackCaptor.getValue();
+        }
+
         when(mPackageManager.hasSystemFeature(PackageManager.FEATURE_WIFI)).thenReturn(true);
         when(mPackageManager.hasSystemFeature(PackageManager.FEATURE_WIFI_DIRECT)).thenReturn(true);
     }
@@ -946,7 +957,7 @@
 
         // Emulate externally-visible WifiManager effects, when hotspot mode
         // is being torn down.
-        sendWifiApStateChanged(WifiManager.WIFI_AP_STATE_DISABLED);
+        sendWifiApStateChanged(WIFI_AP_STATE_DISABLED, TEST_WLAN_IFNAME, IFACE_IP_MODE_LOCAL_ONLY);
         mTethering.interfaceRemoved(TEST_WLAN_IFNAME);
         mLooper.dispatchAll();
 
@@ -1521,7 +1532,7 @@
 
         // Emulate externally-visible WifiManager effects, when tethering mode
         // is being torn down.
-        sendWifiApStateChanged(WifiManager.WIFI_AP_STATE_DISABLED);
+        sendWifiApStateChanged(WIFI_AP_STATE_DISABLED, TEST_WLAN_IFNAME, IFACE_IP_MODE_TETHERED);
         mTethering.interfaceRemoved(TEST_WLAN_IFNAME);
         mLooper.dispatchAll();
 
@@ -1922,7 +1933,13 @@
         mTethering.unregisterTetheringEventCallback(callback);
         mLooper.dispatchAll();
         mTethering.stopTethering(TETHERING_WIFI);
-        sendWifiApStateChanged(WifiManager.WIFI_AP_STATE_DISABLED);
+        sendWifiApStateChanged(WIFI_AP_STATE_DISABLED);
+        if (isAtLeastT()) {
+            // After T, tethering doesn't support WIFI_AP_STATE_DISABLED with null interface name.
+            callback2.assertNoStateChangeCallback();
+            sendWifiApStateChanged(WIFI_AP_STATE_DISABLED, TEST_WLAN_IFNAME,
+                    IFACE_IP_MODE_TETHERED);
+        }
         tetherState = callback2.pollTetherStatesChanged();
         assertArrayEquals(tetherState.availableList, new TetheringInterface[] {wifiIface});
         mLooper.dispatchAll();
@@ -2530,12 +2547,11 @@
         eventCallbacks = dhcpEventCbsCaptor.getValue();
         // Update lease for local only tethering.
         final MacAddress testMac1 = MacAddress.fromString("11:11:11:11:11:11");
-        final ArrayList<DhcpLeaseParcelable> p2pLeases = new ArrayList<>();
-        p2pLeases.add(createDhcpLeaseParcelable("clientId1", testMac1, "192.168.50.24", 24,
-                Long.MAX_VALUE, "test1"));
-        notifyDhcpLeasesChanged(p2pLeases, eventCallbacks);
-        final List<TetheredClient> clients = toTetheredClients(p2pLeases, TETHERING_WIFI_P2P);
-        callback.expectTetheredClientChanged(clients);
+        final DhcpLeaseParcelable p2pLease = createDhcpLeaseParcelable("clientId1", testMac1,
+                "192.168.50.24", 24, Long.MAX_VALUE, "test1");
+        final List<TetheredClient> p2pClients = notifyDhcpLeasesChanged(TETHERING_WIFI_P2P,
+                eventCallbacks, p2pLease);
+        callback.expectTetheredClientChanged(p2pClients);
         reset(mDhcpServer);
 
         // Run wifi tethering.
@@ -2545,25 +2561,20 @@
                 any(), dhcpEventCbsCaptor.capture());
         eventCallbacks = dhcpEventCbsCaptor.getValue();
         // Update mac address from softAp callback before getting dhcp lease.
-        final ArrayList<WifiClient> wifiClients = new ArrayList<>();
         final MacAddress testMac2 = MacAddress.fromString("22:22:22:22:22:22");
-        final WifiClient testClient = mock(WifiClient.class);
-        when(testClient.getMacAddress()).thenReturn(testMac2);
-        wifiClients.add(testClient);
-        mSoftApCallback.onConnectedClientsChanged(wifiClients);
-        final TetheredClient noAddrClient = new TetheredClient(testMac2,
-                Collections.emptyList() /* addresses */, TETHERING_WIFI);
-        clients.add(noAddrClient);
-        callback.expectTetheredClientChanged(clients);
+        final TetheredClient noAddrClient = notifyConnectedWifiClientsChanged(testMac2,
+                false /* isLocalOnly */);
+        final List<TetheredClient> p2pAndNoAddrClients = new ArrayList<>(p2pClients);
+        p2pAndNoAddrClients.add(noAddrClient);
+        callback.expectTetheredClientChanged(p2pAndNoAddrClients);
 
         // Update dhcp lease for wifi tethering.
-        clients.remove(noAddrClient);
-        final ArrayList<DhcpLeaseParcelable> wifiLeases = new ArrayList<>();
-        wifiLeases.add(createDhcpLeaseParcelable("clientId2", testMac2, "192.168.43.24", 24,
-                Long.MAX_VALUE, "test2"));
-        notifyDhcpLeasesChanged(wifiLeases, eventCallbacks);
-        clients.addAll(toTetheredClients(wifiLeases, TETHERING_WIFI));
-        callback.expectTetheredClientChanged(clients);
+        final DhcpLeaseParcelable wifiLease = createDhcpLeaseParcelable("clientId2", testMac2,
+                "192.168.43.24", 24, Long.MAX_VALUE, "test2");
+        final List<TetheredClient> p2pAndWifiClients = new ArrayList<>(p2pClients);
+        p2pAndWifiClients.addAll(notifyDhcpLeasesChanged(TETHERING_WIFI,
+                eventCallbacks, wifiLease));
+        callback.expectTetheredClientChanged(p2pAndWifiClients);
 
         // Test onStarted callback that register second callback when tethering is running.
         TestTetheringEventCallback callback2 = new TestTetheringEventCallback();
@@ -2571,18 +2582,74 @@
             mTethering.registerTetheringEventCallback(callback2);
             mLooper.dispatchAll();
         });
-        callback2.expectTetheredClientChanged(clients);
+        callback2.expectTetheredClientChanged(p2pAndWifiClients);
     }
 
-    private void notifyDhcpLeasesChanged(List<DhcpLeaseParcelable> leaseParcelables,
-            IDhcpEventCallbacks callback) throws Exception {
-        callback.onLeasesChanged(leaseParcelables);
+    @Test
+    @IgnoreUpTo(Build.VERSION_CODES.S_V2)
+    public void testUpdateConnectedClientsForLocalOnlyHotspot() throws Exception {
+        TestTetheringEventCallback callback = new TestTetheringEventCallback();
+        runAsShell(NETWORK_SETTINGS, () -> {
+            mTethering.registerTetheringEventCallback(callback);
+            mLooper.dispatchAll();
+        });
+        callback.expectTetheredClientChanged(Collections.emptyList());
+
+        // Run local only hotspot.
+        mTethering.interfaceStatusChanged(TEST_WLAN_IFNAME, true);
+        sendWifiApStateChanged(WIFI_AP_STATE_ENABLED, TEST_WLAN_IFNAME, IFACE_IP_MODE_LOCAL_ONLY);
+
+        final ArgumentCaptor<IDhcpEventCallbacks> dhcpEventCbsCaptor =
+                 ArgumentCaptor.forClass(IDhcpEventCallbacks.class);
+        verify(mDhcpServer, timeout(DHCPSERVER_START_TIMEOUT_MS)).startWithCallbacks(
+                any(), dhcpEventCbsCaptor.capture());
+        final IDhcpEventCallbacks eventCallbacks = dhcpEventCbsCaptor.getValue();
+        // Update mac address from softAp callback before getting dhcp lease.
+        final MacAddress testMac = MacAddress.fromString("22:22:22:22:22:22");
+        final TetheredClient noAddrClient = notifyConnectedWifiClientsChanged(testMac,
+                true /* isLocalOnly */);
+        final List<TetheredClient> noAddrLocalOnlyClients = new ArrayList<>();
+        noAddrLocalOnlyClients.add(noAddrClient);
+        callback.expectTetheredClientChanged(noAddrLocalOnlyClients);
+
+        // Update dhcp lease for local only hotspot.
+        final DhcpLeaseParcelable wifiLease = createDhcpLeaseParcelable("clientId", testMac,
+                "192.168.43.24", 24, Long.MAX_VALUE, "test");
+        final List<TetheredClient> localOnlyClients = notifyDhcpLeasesChanged(TETHERING_WIFI,
+                eventCallbacks, wifiLease);
+        callback.expectTetheredClientChanged(localOnlyClients);
+
+        // Client disconnect from local only hotspot.
+        mLocalOnlyHotspotCallback.onConnectedClientsChanged(Collections.emptyList());
+        callback.expectTetheredClientChanged(Collections.emptyList());
+    }
+
+    private TetheredClient notifyConnectedWifiClientsChanged(final MacAddress mac,
+            boolean isLocalOnly) throws Exception {
+        final ArrayList<WifiClient> wifiClients = new ArrayList<>();
+        final WifiClient testClient = mock(WifiClient.class);
+        when(testClient.getMacAddress()).thenReturn(mac);
+        wifiClients.add(testClient);
+        if (isLocalOnly) {
+            mLocalOnlyHotspotCallback.onConnectedClientsChanged(wifiClients);
+        } else {
+            mSoftApCallback.onConnectedClientsChanged(wifiClients);
+        }
+        return new TetheredClient(mac, Collections.emptyList() /* addresses */, TETHERING_WIFI);
+    }
+
+    private List<TetheredClient> notifyDhcpLeasesChanged(int type, IDhcpEventCallbacks callback,
+            DhcpLeaseParcelable... leases) throws Exception {
+        final List<DhcpLeaseParcelable> dhcpLeases = Arrays.asList(leases);
+        callback.onLeasesChanged(dhcpLeases);
         mLooper.dispatchAll();
+
+        return toTetheredClients(dhcpLeases, type);
     }
 
     private List<TetheredClient> toTetheredClients(List<DhcpLeaseParcelable> leaseParcelables,
             int type) throws Exception {
-        final ArrayList<TetheredClient> leases = new ArrayList<>();
+        final ArrayList<TetheredClient> clients = new ArrayList<>();
         for (DhcpLeaseParcelable lease : leaseParcelables) {
             final LinkAddress address = new LinkAddress(
                     intToInet4AddressHTH(lease.netAddr), lease.prefixLength,
@@ -2592,13 +2659,13 @@
             final MacAddress macAddress = MacAddress.fromBytes(lease.hwAddr);
 
             final AddressInfo addressInfo = new TetheredClient.AddressInfo(address, lease.hostname);
-            leases.add(new TetheredClient(
+            clients.add(new TetheredClient(
                     macAddress,
                     Collections.singletonList(addressInfo),
                     type));
         }
 
-        return leases;
+        return clients;
     }
 
     private DhcpLeaseParcelable createDhcpLeaseParcelable(final String clientId,
diff --git a/bpf_progs/bpf_shared.h b/bpf_progs/bpf_shared.h
index 5378358..14fcdd6 100644
--- a/bpf_progs/bpf_shared.h
+++ b/bpf_progs/bpf_shared.h
@@ -132,6 +132,7 @@
     RESTRICTED_MATCH = (1 << 5),
     LOW_POWER_STANDBY_MATCH = (1 << 6),
     IIF_MATCH = (1 << 7),
+    LOCKDOWN_VPN_MATCH = (1 << 8),
 };
 
 enum BpfPermissionMatch {
diff --git a/bpf_progs/netd.c b/bpf_progs/netd.c
index e484010..d019257 100644
--- a/bpf_progs/netd.c
+++ b/bpf_progs/netd.c
@@ -217,9 +217,16 @@
             return BPF_DROP;
         }
     }
-    if (direction == BPF_INGRESS && (uidRules & IIF_MATCH)) {
-        // Drops packets not coming from lo nor the allowlisted interface
-        if (allowed_iif && skb->ifindex != 1 && skb->ifindex != allowed_iif) {
+    if (direction == BPF_INGRESS && skb->ifindex != 1) {
+        if (uidRules & IIF_MATCH) {
+            if (allowed_iif && skb->ifindex != allowed_iif) {
+                // Drops packets not coming from lo nor the allowed interface
+                // allowed interface=0 is a wildcard and does not drop packets
+                return BPF_DROP_UNLESS_DNS;
+            }
+        } else if (uidRules & LOCKDOWN_VPN_MATCH) {
+            // Drops packets not coming from lo and rule does not have IIF_MATCH but has
+            // LOCKDOWN_VPN_MATCH
             return BPF_DROP_UNLESS_DNS;
         }
     }
@@ -376,8 +383,7 @@
     return BPF_NOMATCH;
 }
 
-DEFINE_BPF_PROG_KVER("cgroupsock/inet/create", AID_ROOT, AID_ROOT, inet_socket_create,
-                     KVER(4, 14, 0))
+DEFINE_BPF_PROG("cgroupsock/inet/create", AID_ROOT, AID_ROOT, inet_socket_create)
 (struct bpf_sock* sk) {
     uint64_t gid_uid = bpf_get_current_uid_gid();
     /*
diff --git a/framework/src/android/net/ConnectivityManager.java b/framework/src/android/net/ConnectivityManager.java
index d16a6f5..9f9ee95 100644
--- a/framework/src/android/net/ConnectivityManager.java
+++ b/framework/src/android/net/ConnectivityManager.java
@@ -982,6 +982,16 @@
     @SystemApi(client = MODULE_LIBRARIES)
     public static final int FIREWALL_CHAIN_LOW_POWER_STANDBY = 5;
 
+    /**
+     * Firewall chain used for lockdown VPN.
+     * Denylist of apps that cannot receive incoming packets except on loopback because they are
+     * subject to an always-on VPN which is not currently connected.
+     *
+     * @see #BLOCKED_REASON_LOCKDOWN_VPN
+     * @hide
+     */
+    public static final int FIREWALL_CHAIN_LOCKDOWN_VPN = 6;
+
     /** @hide */
     @Retention(RetentionPolicy.SOURCE)
     @IntDef(flag = false, prefix = "FIREWALL_CHAIN_", value = {
@@ -989,7 +999,8 @@
         FIREWALL_CHAIN_STANDBY,
         FIREWALL_CHAIN_POWERSAVE,
         FIREWALL_CHAIN_RESTRICTED,
-        FIREWALL_CHAIN_LOW_POWER_STANDBY
+        FIREWALL_CHAIN_LOW_POWER_STANDBY,
+        FIREWALL_CHAIN_LOCKDOWN_VPN
     })
     public @interface FirewallChain {}
     // LINT.ThenChange(packages/modules/Connectivity/service/native/include/Common.h)
diff --git a/netd/BpfHandler.cpp b/netd/BpfHandler.cpp
index f3dfb57..08e66d9 100644
--- a/netd/BpfHandler.cpp
+++ b/netd/BpfHandler.cpp
@@ -73,16 +73,7 @@
     }
     RETURN_IF_NOT_OK(attachProgramToCgroup(BPF_EGRESS_PROG_PATH, cg_fd, BPF_CGROUP_INET_EGRESS));
     RETURN_IF_NOT_OK(attachProgramToCgroup(BPF_INGRESS_PROG_PATH, cg_fd, BPF_CGROUP_INET_INGRESS));
-
-    // For the devices that support cgroup socket filter, the socket filter
-    // should be loaded successfully by bpfloader. So we attach the filter to
-    // cgroup if the program is pinned properly.
-    // TODO: delete the if statement once all devices should support cgroup
-    // socket filter (ie. the minimum kernel version required is 4.14).
-    if (!access(CGROUP_SOCKET_PROG_PATH, F_OK)) {
-        RETURN_IF_NOT_OK(
-                attachProgramToCgroup(CGROUP_SOCKET_PROG_PATH, cg_fd, BPF_CGROUP_INET_SOCK_CREATE));
-    }
+    RETURN_IF_NOT_OK(attachProgramToCgroup(CGROUP_SOCKET_PROG_PATH, cg_fd, BPF_CGROUP_INET_SOCK_CREATE));
     return netdutils::status::ok;
 }
 
diff --git a/service-t/src/com/android/server/NsdService.java b/service-t/src/com/android/server/NsdService.java
index ea57bac..6def44f 100644
--- a/service-t/src/com/android/server/NsdService.java
+++ b/service-t/src/com/android/server/NsdService.java
@@ -513,7 +513,7 @@
                             break;
                         }
 
-                        String name = fullName.substring(0, index);
+                        String name = unescape(fullName.substring(0, index));
                         String rest = fullName.substring(index);
                         String type = rest.replace(".local.", "");
 
@@ -590,6 +590,35 @@
        }
     }
 
+    // The full service name is escaped from standard DNS rules on mdnsresponder, making it suitable
+    // for passing to standard system DNS APIs such as res_query() . Thus, make the service name
+    // unescape for getting right service address. See "Notes on DNS Name Escaping" on
+    // external/mdnsresponder/mDNSShared/dns_sd.h for more details.
+    private String unescape(String s) {
+        StringBuilder sb = new StringBuilder(s.length());
+        for (int i = 0; i < s.length(); ++i) {
+            char c = s.charAt(i);
+            if (c == '\\') {
+                if (++i >= s.length()) {
+                    Log.e(TAG, "Unexpected end of escape sequence in: " + s);
+                    break;
+                }
+                c = s.charAt(i);
+                if (c != '.' && c != '\\') {
+                    if (i + 2 >= s.length()) {
+                        Log.e(TAG, "Unexpected end of escape sequence in: " + s);
+                        break;
+                    }
+                    c = (char) ((c - '0') * 100 + (s.charAt(i + 1) - '0') * 10
+                            + (s.charAt(i + 2) - '0'));
+                    i += 2;
+                }
+            }
+            sb.append(c);
+        }
+        return sb.toString();
+    }
+
     @VisibleForTesting
     NsdService(Context ctx, Handler handler, long cleanupDelayMs) {
         mCleanupDelayMs = cleanupDelayMs;
diff --git a/service/jni/com_android_server_BpfNetMaps.cpp b/service/jni/com_android_server_BpfNetMaps.cpp
index f13c68d..7b1f59c 100644
--- a/service/jni/com_android_server_BpfNetMaps.cpp
+++ b/service/jni/com_android_server_BpfNetMaps.cpp
@@ -133,12 +133,16 @@
 
 static jint native_addUidInterfaceRules(JNIEnv* env, jobject clazz, jstring ifName,
                                     jintArray jUids) {
-    const ScopedUtfChars ifNameUtf8(env, ifName);
-    if (ifNameUtf8.c_str() == nullptr) {
-        return -EINVAL;
+    // Null ifName is a wildcard to allow apps to receive packets on all interfaces and ifIndex is
+    // set to 0.
+    int ifIndex;
+    if (ifName != nullptr) {
+        const ScopedUtfChars ifNameUtf8(env, ifName);
+        const std::string interfaceName(ifNameUtf8.c_str());
+        ifIndex = if_nametoindex(interfaceName.c_str());
+    } else {
+        ifIndex = 0;
     }
-    const std::string interfaceName(ifNameUtf8.c_str());
-    const int ifIndex = if_nametoindex(interfaceName.c_str());
 
     ScopedIntArrayRO uids(env, jUids);
     if (uids.get() == nullptr) {
diff --git a/service/native/TrafficController.cpp b/service/native/TrafficController.cpp
index 473c9e3..5581c40 100644
--- a/service/native/TrafficController.cpp
+++ b/service/native/TrafficController.cpp
@@ -98,6 +98,7 @@
     FLAG_MSG_TRANS(matchType, RESTRICTED_MATCH, match);
     FLAG_MSG_TRANS(matchType, LOW_POWER_STANDBY_MATCH, match);
     FLAG_MSG_TRANS(matchType, IIF_MATCH, match);
+    FLAG_MSG_TRANS(matchType, LOCKDOWN_VPN_MATCH, match);
     if (match) {
         return StringPrintf("Unknown match: %u", match);
     }
@@ -286,16 +287,13 @@
 }
 
 Status TrafficController::addRule(uint32_t uid, UidOwnerMatchType match, uint32_t iif) {
-    // iif should be non-zero if and only if match == MATCH_IIF
-    if (match == IIF_MATCH && iif == 0) {
-        return statusFromErrno(EINVAL, "Interface match must have nonzero interface index");
-    } else if (match != IIF_MATCH && iif != 0) {
+    if (match != IIF_MATCH && iif != 0) {
         return statusFromErrno(EINVAL, "Non-interface match must have zero interface index");
     }
     auto oldMatch = mUidOwnerMap.readValue(uid);
     if (oldMatch.ok()) {
         UidOwnerValue newMatch = {
-                .iif = iif ? iif : oldMatch.value().iif,
+                .iif = (match == IIF_MATCH) ? iif : oldMatch.value().iif,
                 .rule = oldMatch.value().rule | match,
         };
         RETURN_IF_NOT_OK(mUidOwnerMap.writeValue(uid, newMatch, BPF_ANY));
@@ -335,6 +333,8 @@
             return ALLOWLIST;
         case LOW_POWER_STANDBY:
             return ALLOWLIST;
+        case LOCKDOWN:
+            return DENYLIST;
         case NONE:
         default:
             return DENYLIST;
@@ -360,6 +360,9 @@
         case LOW_POWER_STANDBY:
             res = updateOwnerMapEntry(LOW_POWER_STANDBY_MATCH, uid, rule, type);
             break;
+        case LOCKDOWN:
+            res = updateOwnerMapEntry(LOCKDOWN_VPN_MATCH, uid, rule, type);
+            break;
         case NONE:
         default:
             ALOGW("Unknown child chain: %d", chain);
@@ -399,9 +402,6 @@
 
 Status TrafficController::addUidInterfaceRules(const int iif,
                                                const std::vector<int32_t>& uidsToAdd) {
-    if (!iif) {
-        return statusFromErrno(EINVAL, "Interface rule must specify interface");
-    }
     std::lock_guard guard(mMutex);
 
     for (auto uid : uidsToAdd) {
diff --git a/service/native/TrafficControllerTest.cpp b/service/native/TrafficControllerTest.cpp
index 9529cae..ad53cb8 100644
--- a/service/native/TrafficControllerTest.cpp
+++ b/service/native/TrafficControllerTest.cpp
@@ -307,6 +307,7 @@
     checkUidOwnerRuleForChain(POWERSAVE, POWERSAVE_MATCH);
     checkUidOwnerRuleForChain(RESTRICTED, RESTRICTED_MATCH);
     checkUidOwnerRuleForChain(LOW_POWER_STANDBY, LOW_POWER_STANDBY_MATCH);
+    checkUidOwnerRuleForChain(LOCKDOWN, LOCKDOWN_VPN_MATCH);
     ASSERT_EQ(-EINVAL, mTc.changeUidOwnerRule(NONE, TEST_UID, ALLOW, ALLOWLIST));
     ASSERT_EQ(-EINVAL, mTc.changeUidOwnerRule(INVALID_CHAIN, TEST_UID, ALLOW, ALLOWLIST));
 }
@@ -491,6 +492,70 @@
     checkEachUidValue({10001, 10002}, IIF_MATCH);
 }
 
+TEST_F(TrafficControllerTest, TestAddUidInterfaceFilteringRulesWithWildcard) {
+    // iif=0 is a wildcard
+    int iif = 0;
+    // Add interface rule with wildcard to uids
+    ASSERT_TRUE(isOk(mTc.addUidInterfaceRules(iif, {1000, 1001})));
+    expectUidOwnerMapValues({1000, 1001}, IIF_MATCH, iif);
+}
+
+TEST_F(TrafficControllerTest, TestRemoveUidInterfaceFilteringRulesWithWildcard) {
+    // iif=0 is a wildcard
+    int iif = 0;
+    // Add interface rule with wildcard to two uids
+    ASSERT_TRUE(isOk(mTc.addUidInterfaceRules(iif, {1000, 1001})));
+    expectUidOwnerMapValues({1000, 1001}, IIF_MATCH, iif);
+
+    // Remove interface rule from one of the uids
+    ASSERT_TRUE(isOk(mTc.removeUidInterfaceRules({1000})));
+    expectUidOwnerMapValues({1001}, IIF_MATCH, iif);
+    checkEachUidValue({1001}, IIF_MATCH);
+
+    // Remove interface rule from the remaining uid
+    ASSERT_TRUE(isOk(mTc.removeUidInterfaceRules({1001})));
+    expectMapEmpty(mFakeUidOwnerMap);
+}
+
+TEST_F(TrafficControllerTest, TestUidInterfaceFilteringRulesWithWildcardAndExistingMatches) {
+    // Set up existing DOZABLE_MATCH and POWERSAVE_MATCH rule
+    ASSERT_TRUE(isOk(updateUidOwnerMaps({1000}, DOZABLE_MATCH,
+                                        TrafficController::IptOpInsert)));
+    ASSERT_TRUE(isOk(updateUidOwnerMaps({1000}, POWERSAVE_MATCH,
+                                        TrafficController::IptOpInsert)));
+
+    // iif=0 is a wildcard
+    int iif = 0;
+    // Add interface rule with wildcard to the existing uid
+    ASSERT_TRUE(isOk(mTc.addUidInterfaceRules(iif, {1000})));
+    expectUidOwnerMapValues({1000}, POWERSAVE_MATCH | DOZABLE_MATCH | IIF_MATCH, iif);
+
+    // Remove interface rule with wildcard from the existing uid
+    ASSERT_TRUE(isOk(mTc.removeUidInterfaceRules({1000})));
+    expectUidOwnerMapValues({1000}, POWERSAVE_MATCH | DOZABLE_MATCH, 0);
+}
+
+TEST_F(TrafficControllerTest, TestUidInterfaceFilteringRulesWithWildcardAndNewMatches) {
+    // iif=0 is a wildcard
+    int iif = 0;
+    // Set up existing interface rule with wildcard
+    ASSERT_TRUE(isOk(mTc.addUidInterfaceRules(iif, {1000})));
+
+    // Add DOZABLE_MATCH and POWERSAVE_MATCH rule to the existing uid
+    ASSERT_TRUE(isOk(updateUidOwnerMaps({1000}, DOZABLE_MATCH,
+                                        TrafficController::IptOpInsert)));
+    ASSERT_TRUE(isOk(updateUidOwnerMaps({1000}, POWERSAVE_MATCH,
+                                        TrafficController::IptOpInsert)));
+    expectUidOwnerMapValues({1000}, POWERSAVE_MATCH | DOZABLE_MATCH | IIF_MATCH, iif);
+
+    // Remove DOZABLE_MATCH and POWERSAVE_MATCH rule from the existing uid
+    ASSERT_TRUE(isOk(updateUidOwnerMaps({1000}, DOZABLE_MATCH,
+                                        TrafficController::IptOpDelete)));
+    ASSERT_TRUE(isOk(updateUidOwnerMaps({1000}, POWERSAVE_MATCH,
+                                        TrafficController::IptOpDelete)));
+    expectUidOwnerMapValues({1000}, IIF_MATCH, iif);
+}
+
 TEST_F(TrafficControllerTest, TestGrantInternetPermission) {
     std::vector<uid_t> appUids = {TEST_UID, TEST_UID2, TEST_UID3};
 
diff --git a/service/native/include/Common.h b/service/native/include/Common.h
index dc44845..847acec 100644
--- a/service/native/include/Common.h
+++ b/service/native/include/Common.h
@@ -35,6 +35,7 @@
     POWERSAVE = 3,
     RESTRICTED = 4,
     LOW_POWER_STANDBY = 5,
+    LOCKDOWN = 6,
     INVALID_CHAIN
 };
 // LINT.ThenChange(packages/modules/Connectivity/framework/src/android/net/ConnectivityManager.java)
diff --git a/service/src/com/android/server/ConnectivityService.java b/service/src/com/android/server/ConnectivityService.java
index 88bc058..6e6b020 100644
--- a/service/src/com/android/server/ConnectivityService.java
+++ b/service/src/com/android/server/ConnectivityService.java
@@ -5969,6 +5969,10 @@
                     + Arrays.toString(ranges) + "): netd command failed: " + e);
         }
 
+        if (SdkLevel.isAtLeastT()) {
+            mPermissionMonitor.updateVpnLockdownUidRanges(requireVpn, ranges);
+        }
+
         for (final NetworkAgentInfo nai : mNetworkAgentInfos) {
             final boolean curMetered = nai.networkCapabilities.isMetered();
             maybeNotifyNetworkBlocked(nai, curMetered, curMetered,
@@ -7732,10 +7736,10 @@
 
     private void updateVpnFiltering(LinkProperties newLp, LinkProperties oldLp,
             NetworkAgentInfo nai) {
-        final String oldIface = oldLp != null ? oldLp.getInterfaceName() : null;
-        final String newIface = newLp != null ? newLp.getInterfaceName() : null;
-        final boolean wasFiltering = requiresVpnIsolation(nai, nai.networkCapabilities, oldLp);
-        final boolean needsFiltering = requiresVpnIsolation(nai, nai.networkCapabilities, newLp);
+        final String oldIface = getVpnIsolationInterface(nai, nai.networkCapabilities, oldLp);
+        final String newIface = getVpnIsolationInterface(nai, nai.networkCapabilities, newLp);
+        final boolean wasFiltering = requiresVpnAllowRule(nai, oldLp, oldIface);
+        final boolean needsFiltering = requiresVpnAllowRule(nai, newLp, newIface);
 
         if (!wasFiltering && !needsFiltering) {
             // Nothing to do.
@@ -7748,11 +7752,19 @@
         }
 
         final Set<UidRange> ranges = nai.networkCapabilities.getUidRanges();
+        if (ranges == null || ranges.isEmpty()) {
+            return;
+        }
+
         final int vpnAppUid = nai.networkCapabilities.getOwnerUid();
         // TODO: this create a window of opportunity for apps to receive traffic between the time
         // when the old rules are removed and the time when new rules are added. To fix this,
         // make eBPF support two allowlisted interfaces so here new rules can be added before the
         // old rules are being removed.
+
+        // Null iface given to onVpnUidRangesAdded/Removed is a wildcard to allow apps to receive
+        // packets on all interfaces. This is required to accept incoming traffic in Lockdown mode
+        // by overriding the Lockdown blocking rule.
         if (wasFiltering) {
             mPermissionMonitor.onVpnUidRangesRemoved(oldIface, ranges, vpnAppUid);
         }
@@ -8041,15 +8053,14 @@
     }
 
     /**
-     * Returns whether VPN isolation (ingress interface filtering) should be applied on the given
-     * network.
+     * Returns the interface which requires VPN isolation (ingress interface filtering).
      *
      * Ingress interface filtering enforces that all apps under the given network can only receive
      * packets from the network's interface (and loopback). This is important for VPNs because
      * apps that cannot bypass a fully-routed VPN shouldn't be able to receive packets from any
      * non-VPN interfaces.
      *
-     * As a result, this method should return true iff
+     * As a result, this method should return Non-null interface iff
      *  1. the network is an app VPN (not legacy VPN)
      *  2. the VPN does not allow bypass
      *  3. the VPN is fully-routed
@@ -8058,16 +8069,32 @@
      * @see INetd#firewallAddUidInterfaceRules
      * @see INetd#firewallRemoveUidInterfaceRules
      */
-    private boolean requiresVpnIsolation(@NonNull NetworkAgentInfo nai, NetworkCapabilities nc,
+    @Nullable
+    private String getVpnIsolationInterface(@NonNull NetworkAgentInfo nai, NetworkCapabilities nc,
             LinkProperties lp) {
-        if (nc == null || lp == null) return false;
-        return nai.isVPN()
+        if (nc == null || lp == null) return null;
+        if (nai.isVPN()
                 && !nai.networkAgentConfig.allowBypass
                 && nc.getOwnerUid() != Process.SYSTEM_UID
                 && lp.getInterfaceName() != null
                 && (lp.hasIpv4DefaultRoute() || lp.hasIpv4UnreachableDefaultRoute())
                 && (lp.hasIpv6DefaultRoute() || lp.hasIpv6UnreachableDefaultRoute())
-                && !lp.hasExcludeRoute();
+                && !lp.hasExcludeRoute()) {
+            return lp.getInterfaceName();
+        }
+        return null;
+    }
+
+    /**
+     * Returns whether we need to set interface filtering rule or not
+     */
+    private boolean requiresVpnAllowRule(NetworkAgentInfo nai, LinkProperties lp,
+            String filterIface) {
+        // Only filter if lp has an interface.
+        if (lp == null || lp.getInterfaceName() == null) return false;
+        // Before T, allow rules are only needed if VPN isolation is enabled.
+        // T and After T, allow rules are needed for all VPNs.
+        return filterIface != null || (nai.isVPN() && SdkLevel.isAtLeastT());
     }
 
     private static UidRangeParcel[] toUidRangeStableParcels(final @NonNull Set<UidRange> ranges) {
@@ -8195,9 +8222,10 @@
             if (!prevRanges.isEmpty()) {
                 updateVpnUidRanges(false, nai, prevRanges);
             }
-            final boolean wasFiltering = requiresVpnIsolation(nai, prevNc, nai.linkProperties);
-            final boolean shouldFilter = requiresVpnIsolation(nai, newNc, nai.linkProperties);
-            final String iface = nai.linkProperties.getInterfaceName();
+            final String oldIface = getVpnIsolationInterface(nai, prevNc, nai.linkProperties);
+            final String newIface = getVpnIsolationInterface(nai, newNc, nai.linkProperties);
+            final boolean wasFiltering = requiresVpnAllowRule(nai, nai.linkProperties, oldIface);
+            final boolean shouldFilter = requiresVpnAllowRule(nai, nai.linkProperties, newIface);
             // For VPN uid interface filtering, old ranges need to be removed before new ranges can
             // be added, due to the range being expanded and stored as individual UIDs. For example
             // the UIDs might be updated from [0, 99999] to ([0, 10012], [10014, 99999]) which means
@@ -8209,11 +8237,16 @@
             // above, where the addition of new ranges happens before the removal of old ranges.
             // TODO Fix this window by computing an accurate diff on Set<UidRange>, so the old range
             // to be removed will never overlap with the new range to be added.
+
+            // Null iface given to onVpnUidRangesAdded/Removed is a wildcard to allow apps to
+            // receive packets on all interfaces. This is required to accept incoming traffic in
+            // Lockdown mode by overriding the Lockdown blocking rule.
             if (wasFiltering && !prevRanges.isEmpty()) {
-                mPermissionMonitor.onVpnUidRangesRemoved(iface, prevRanges, prevNc.getOwnerUid());
+                mPermissionMonitor.onVpnUidRangesRemoved(oldIface, prevRanges,
+                        prevNc.getOwnerUid());
             }
             if (shouldFilter && !newRanges.isEmpty()) {
-                mPermissionMonitor.onVpnUidRangesAdded(iface, newRanges, newNc.getOwnerUid());
+                mPermissionMonitor.onVpnUidRangesAdded(newIface, newRanges, newNc.getOwnerUid());
             }
         } catch (Exception e) {
             // Never crash!
diff --git a/service/src/com/android/server/connectivity/PermissionMonitor.java b/service/src/com/android/server/connectivity/PermissionMonitor.java
index 8d99cb4..e4a2c20 100755
--- a/service/src/com/android/server/connectivity/PermissionMonitor.java
+++ b/service/src/com/android/server/connectivity/PermissionMonitor.java
@@ -23,6 +23,9 @@
 import static android.Manifest.permission.UPDATE_DEVICE_STATS;
 import static android.content.pm.PackageInfo.REQUESTED_PERMISSION_GRANTED;
 import static android.content.pm.PackageManager.GET_PERMISSIONS;
+import static android.net.ConnectivityManager.FIREWALL_CHAIN_LOCKDOWN_VPN;
+import static android.net.ConnectivityManager.FIREWALL_RULE_ALLOW;
+import static android.net.ConnectivityManager.FIREWALL_RULE_DENY;
 import static android.net.ConnectivitySettingsManager.UIDS_ALLOWED_ON_RESTRICTED_NETWORKS;
 import static android.net.INetd.PERMISSION_INTERNET;
 import static android.net.INetd.PERMISSION_NETWORK;
@@ -37,6 +40,7 @@
 import static com.android.net.module.util.CollectionUtils.toIntArray;
 
 import android.annotation.NonNull;
+import android.annotation.Nullable;
 import android.content.BroadcastReceiver;
 import android.content.Context;
 import android.content.Intent;
@@ -74,7 +78,6 @@
 import com.android.server.BpfNetMaps;
 
 import java.util.ArrayList;
-import java.util.HashMap;
 import java.util.HashSet;
 import java.util.List;
 import java.util.Map;
@@ -108,10 +111,19 @@
     @GuardedBy("this")
     private final SparseIntArray mUidToNetworkPerm = new SparseIntArray();
 
-    // Keys are active non-bypassable and fully-routed VPN's interface name, Values are uid ranges
-    // for apps under the VPN
+    // NonNull keys are active non-bypassable and fully-routed VPN's interface name, Values are uid
+    // ranges for apps under the VPNs which enable interface filtering.
+    // If key is null, Values are uid ranges for apps under the VPNs which are connected but do not
+    // enable interface filtering.
     @GuardedBy("this")
-    private final Map<String, Set<UidRange>> mVpnUidRanges = new HashMap<>();
+    private final Map<String, Set<UidRange>> mVpnInterfaceUidRanges = new ArrayMap<>();
+
+    // Items are uid ranges for apps under the VPN Lockdown
+    // Ranges were given through ConnectivityManager#setRequireVpnForUids, and ranges are allowed to
+    // have duplicates. Also, it is allowed to give ranges that are already subject to lockdown.
+    // So we need to maintain uid range with multiset.
+    @GuardedBy("this")
+    private final MultiSet<UidRange> mVpnLockdownUidRanges = new MultiSet<>();
 
     // A set of appIds for apps across all users on the device. We track appIds instead of uids
     // directly to reduce its size and also eliminate the need to update this set when user is
@@ -201,6 +213,38 @@
         }
     }
 
+    private static class MultiSet<T> {
+        private final Map<T, Integer> mMap = new ArrayMap<>();
+
+        /**
+         * Returns the number of key in the set before this addition.
+         */
+        public int add(T key) {
+            final int oldCount = mMap.getOrDefault(key, 0);
+            mMap.put(key, oldCount + 1);
+            return oldCount;
+        }
+
+        /**
+         * Return the number of key in the set before this removal.
+         */
+        public int remove(T key) {
+            final int oldCount = mMap.getOrDefault(key, 0);
+            if (oldCount == 0) {
+                Log.wtf(TAG, "Attempt to remove non existing key = " + key.toString());
+            } else if (oldCount == 1) {
+                mMap.remove(key);
+            } else {
+                mMap.put(key, oldCount - 1);
+            }
+            return oldCount;
+        }
+
+        public Set<T> getSet() {
+            return mMap.keySet();
+        }
+    }
+
     public PermissionMonitor(@NonNull final Context context, @NonNull final INetd netd,
             @NonNull final BpfNetMaps bpfNetMaps) {
         this(context, netd, bpfNetMaps, new Dependencies());
@@ -626,16 +670,26 @@
     }
 
     private synchronized void updateVpnUid(int uid, boolean add) {
-        for (Map.Entry<String, Set<UidRange>> vpn : mVpnUidRanges.entrySet()) {
+        // Apps that can use restricted networks can always bypass VPNs.
+        if (hasRestrictedNetworksPermission(uid)) {
+            return;
+        }
+        for (Map.Entry<String, Set<UidRange>> vpn : mVpnInterfaceUidRanges.entrySet()) {
             if (UidRange.containsUid(vpn.getValue(), uid)) {
                 final Set<Integer> changedUids = new HashSet<>();
                 changedUids.add(uid);
-                removeBypassingUids(changedUids, -1 /* vpnAppUid */);
                 updateVpnUidsInterfaceRules(vpn.getKey(), changedUids, add);
             }
         }
     }
 
+    private synchronized void updateLockdownUid(int uid, boolean add) {
+        if (UidRange.containsUid(mVpnLockdownUidRanges.getSet(), uid)
+                && !hasRestrictedNetworksPermission(uid)) {
+            updateLockdownUidRule(uid, add);
+        }
+    }
+
     /**
      * This handles both network and traffic permission, because there is no overlap in actual
      * values, where network permission is NETWORK or SYSTEM, and traffic permission is INTERNET
@@ -729,9 +783,10 @@
 
         // If the newly-installed package falls within some VPN's uid range, update Netd with it.
         // This needs to happen after the mUidToNetworkPerm update above, since
-        // removeBypassingUids() in updateVpnUid() depends on mUidToNetworkPerm to check if the
-        // package can bypass VPN.
+        // hasRestrictedNetworksPermission() in updateVpnUid() and updateLockdownUid() depends on
+        // mUidToNetworkPerm to check if the package can bypass VPN.
         updateVpnUid(uid, true /* add */);
+        updateLockdownUid(uid, true /* add */);
         mAllApps.add(appId);
 
         // Log package added.
@@ -775,9 +830,10 @@
 
         // If the newly-removed package falls within some VPN's uid range, update Netd with it.
         // This needs to happen before the mUidToNetworkPerm update below, since
-        // removeBypassingUids() in updateVpnUid() depends on mUidToNetworkPerm to check if the
-        // package can bypass VPN.
+        // hasRestrictedNetworksPermission() in updateVpnUid() and updateLockdownUid() depends on
+        // mUidToNetworkPerm to check if the package can bypass VPN.
         updateVpnUid(uid, false /* add */);
+        updateLockdownUid(uid, false /* add */);
         // If the package has been removed from all users on the device, clear it form mAllApps.
         if (mPackageManager.getNameForUid(uid) == null) {
             mAllApps.remove(appId);
@@ -859,48 +915,100 @@
     /**
      * Called when a new set of UID ranges are added to an active VPN network
      *
-     * @param iface The active VPN network's interface name
+     * @param iface The active VPN network's interface name. Null iface indicates that the app is
+     *              allowed to receive packets on all interfaces.
      * @param rangesToAdd The new UID ranges to be added to the network
      * @param vpnAppUid The uid of the VPN app
      */
-    public synchronized void onVpnUidRangesAdded(@NonNull String iface, Set<UidRange> rangesToAdd,
+    public synchronized void onVpnUidRangesAdded(@Nullable String iface, Set<UidRange> rangesToAdd,
             int vpnAppUid) {
         // Calculate the list of new app uids under the VPN due to the new UID ranges and update
         // Netd about them. Because mAllApps only contains appIds instead of uids, the result might
         // be an overestimation if an app is not installed on the user on which the VPN is running,
-        // but that's safe.
+        // but that's safe: if an app is not installed, it cannot receive any packets, so dropping
+        // packets to that UID is fine.
         final Set<Integer> changedUids = intersectUids(rangesToAdd, mAllApps);
         removeBypassingUids(changedUids, vpnAppUid);
         updateVpnUidsInterfaceRules(iface, changedUids, true /* add */);
-        if (mVpnUidRanges.containsKey(iface)) {
-            mVpnUidRanges.get(iface).addAll(rangesToAdd);
+        if (mVpnInterfaceUidRanges.containsKey(iface)) {
+            mVpnInterfaceUidRanges.get(iface).addAll(rangesToAdd);
         } else {
-            mVpnUidRanges.put(iface, new HashSet<UidRange>(rangesToAdd));
+            mVpnInterfaceUidRanges.put(iface, new HashSet<UidRange>(rangesToAdd));
         }
     }
 
     /**
      * Called when a set of UID ranges are removed from an active VPN network
      *
-     * @param iface The VPN network's interface name
+     * @param iface The VPN network's interface name. Null iface indicates that the app is allowed
+     *              to receive packets on all interfaces.
      * @param rangesToRemove Existing UID ranges to be removed from the VPN network
      * @param vpnAppUid The uid of the VPN app
      */
-    public synchronized void onVpnUidRangesRemoved(@NonNull String iface,
+    public synchronized void onVpnUidRangesRemoved(@Nullable String iface,
             Set<UidRange> rangesToRemove, int vpnAppUid) {
         // Calculate the list of app uids that are no longer under the VPN due to the removed UID
         // ranges and update Netd about them.
         final Set<Integer> changedUids = intersectUids(rangesToRemove, mAllApps);
         removeBypassingUids(changedUids, vpnAppUid);
         updateVpnUidsInterfaceRules(iface, changedUids, false /* add */);
-        Set<UidRange> existingRanges = mVpnUidRanges.getOrDefault(iface, null);
+        Set<UidRange> existingRanges = mVpnInterfaceUidRanges.getOrDefault(iface, null);
         if (existingRanges == null) {
             loge("Attempt to remove unknown vpn uid Range iface = " + iface);
             return;
         }
         existingRanges.removeAll(rangesToRemove);
         if (existingRanges.size() == 0) {
-            mVpnUidRanges.remove(iface);
+            mVpnInterfaceUidRanges.remove(iface);
+        }
+    }
+
+    /**
+     * Called when UID ranges under VPN Lockdown are updated
+     *
+     * @param add {@code true} if the uids are to be added to the Lockdown, {@code false} if they
+     *        are to be removed from the Lockdown.
+     * @param ranges The updated UID ranges under VPN Lockdown. This function does not treat the VPN
+     *               app's UID in any special way. The caller is responsible for excluding the VPN
+     *               app UID from the passed-in ranges.
+     *               Ranges can have duplications and/or contain the range that is already subject
+     *               to lockdown. However, ranges can not have overlaps with other ranges including
+     *               ranges that are currently subject to lockdown.
+     */
+    public synchronized void updateVpnLockdownUidRanges(boolean add, UidRange[] ranges) {
+        final Set<UidRange> affectedUidRanges = new HashSet<>();
+
+        for (final UidRange range : ranges) {
+            if (add) {
+                // Rule will be added if mVpnLockdownUidRanges does not have this uid range entry
+                // currently.
+                if (mVpnLockdownUidRanges.add(range) == 0) {
+                    affectedUidRanges.add(range);
+                }
+            } else {
+                // Rule will be removed if the number of the range in the set is 1 before the
+                // removal.
+                if (mVpnLockdownUidRanges.remove(range) == 1) {
+                    affectedUidRanges.add(range);
+                }
+            }
+        }
+
+        // mAllApps only contains appIds instead of uids. So the generated uid list might contain
+        // apps that are installed only on some users but not others. But that's safe: if an app is
+        // not installed, it cannot receive any packets, so dropping packets to that UID is fine.
+        final Set<Integer> affectedUids = intersectUids(affectedUidRanges, mAllApps);
+
+        // We skip adding rule to privileged apps and allow them to bypass incoming packet
+        // filtering. The behaviour is consistent with how lockdown works for outgoing packets, but
+        // the implementation is different: while ConnectivityService#setRequireVpnForUids does not
+        // exclude privileged apps from the prohibit routing rules used to implement outgoing packet
+        // filtering, privileged apps can still bypass outgoing packet filtering because the
+        // prohibit rules observe the protected from VPN bit.
+        for (final int uid: affectedUids) {
+            if (!hasRestrictedNetworksPermission(uid)) {
+                updateLockdownUidRule(uid, add);
+            }
         }
     }
 
@@ -939,7 +1047,7 @@
      */
     private void removeBypassingUids(Set<Integer> uids, int vpnAppUid) {
         uids.remove(vpnAppUid);
-        uids.removeIf(uid -> mUidToNetworkPerm.get(uid, PERMISSION_NONE) == PERMISSION_SYSTEM);
+        uids.removeIf(this::hasRestrictedNetworksPermission);
     }
 
     /**
@@ -948,6 +1056,7 @@
      *
      * This is to instruct netd to set up appropriate filtering rules for these uids, such that they
      * can only receive ingress packets from the VPN's tunnel interface (and loopback).
+     * Null iface set up a wildcard rule that allow app to receive packets on all interfaces.
      *
      * @param iface the interface name of the active VPN connection
      * @param add {@code true} if the uids are to be added to the interface, {@code false} if they
@@ -968,6 +1077,18 @@
         }
     }
 
+    private void updateLockdownUidRule(int uid, boolean add) {
+        try {
+            if (add) {
+                mBpfNetMaps.setUidRule(FIREWALL_CHAIN_LOCKDOWN_VPN, uid, FIREWALL_RULE_DENY);
+            } else {
+                mBpfNetMaps.setUidRule(FIREWALL_CHAIN_LOCKDOWN_VPN, uid, FIREWALL_RULE_ALLOW);
+            }
+        } catch (ServiceSpecificException e) {
+            loge("Failed to " + (add ? "add" : "remove") + " Lockdown rule: " + e);
+        }
+    }
+
     /**
      * Send the updated permission information to netd. Called upon package install/uninstall.
      *
@@ -1055,8 +1176,14 @@
 
     /** Should only be used by unit tests */
     @VisibleForTesting
-    public Set<UidRange> getVpnUidRanges(String iface) {
-        return mVpnUidRanges.get(iface);
+    public Set<UidRange> getVpnInterfaceUidRanges(String iface) {
+        return mVpnInterfaceUidRanges.get(iface);
+    }
+
+    /** Should only be used by unit tests */
+    @VisibleForTesting
+    public Set<UidRange> getVpnLockdownUidRanges() {
+        return mVpnLockdownUidRanges.getSet();
     }
 
     private synchronized void onSettingChanged() {
@@ -1121,7 +1248,7 @@
     public void dump(IndentingPrintWriter pw) {
         pw.println("Interface filtering rules:");
         pw.increaseIndent();
-        for (Map.Entry<String, Set<UidRange>> vpn : mVpnUidRanges.entrySet()) {
+        for (Map.Entry<String, Set<UidRange>> vpn : mVpnInterfaceUidRanges.entrySet()) {
             pw.println("Interface: " + vpn.getKey());
             pw.println("UIDs: " + vpn.getValue().toString());
             pw.println();
@@ -1129,6 +1256,14 @@
         pw.decreaseIndent();
 
         pw.println();
+        pw.println("Lockdown filtering rules:");
+        pw.increaseIndent();
+        for (final UidRange range : mVpnLockdownUidRanges.getSet()) {
+            pw.println("UIDs: " + range.toString());
+        }
+        pw.decreaseIndent();
+
+        pw.println();
         pw.println("Update logs:");
         pw.increaseIndent();
         mPermissionUpdateLogs.reverseDump(pw);
diff --git a/tests/cts/net/src/android/net/cts/NsdManagerTest.kt b/tests/cts/net/src/android/net/cts/NsdManagerTest.kt
index 6c5b792..088d202 100644
--- a/tests/cts/net/src/android/net/cts/NsdManagerTest.kt
+++ b/tests/cts/net/src/android/net/cts/NsdManagerTest.kt
@@ -608,6 +608,41 @@
         }
     }
 
+    @Test
+    fun testNsdManager_RegisterServiceNameWithNonStandardCharacters() {
+        val serviceNames = "^Nsd.Test|Non-#AsCiI\\Characters&\\ufffe テスト 測試"
+        val si = NsdServiceInfo().apply {
+            serviceType = SERVICE_TYPE
+            serviceName = serviceNames
+            port = 12345 // Test won't try to connect so port does not matter
+        }
+
+        // Register the service name which contains non-standard characters.
+        val registrationRecord = NsdRegistrationRecord()
+        nsdManager.registerService(si, NsdManager.PROTOCOL_DNS_SD, registrationRecord)
+        registrationRecord.expectCallback<ServiceRegistered>()
+
+        tryTest {
+            // Discover that service name.
+            val discoveryRecord = NsdDiscoveryRecord()
+            nsdManager.discoverServices(
+                SERVICE_TYPE, NsdManager.PROTOCOL_DNS_SD, discoveryRecord
+            )
+            val foundInfo = discoveryRecord.waitForServiceDiscovered(serviceNames)
+
+            // Expect that resolving the service name works properly even service name contains
+            // non-standard characters.
+            val resolveRecord = NsdResolveRecord()
+            nsdManager.resolveService(foundInfo, resolveRecord)
+            val resolvedCb = resolveRecord.expectCallback<ServiceResolved>()
+            assertEquals(foundInfo.serviceName, resolvedCb.serviceInfo.serviceName)
+        } cleanupStep {
+            nsdManager.unregisterService(registrationRecord)
+        } cleanup {
+            registrationRecord.expectCallback<ServiceUnregistered>()
+        }
+    }
+
     /**
      * Register a service and return its registration record.
      */
diff --git a/tests/unit/java/com/android/server/ConnectivityServiceTest.java b/tests/unit/java/com/android/server/ConnectivityServiceTest.java
index 3374672..52cebec 100644
--- a/tests/unit/java/com/android/server/ConnectivityServiceTest.java
+++ b/tests/unit/java/com/android/server/ConnectivityServiceTest.java
@@ -51,6 +51,9 @@
 import static android.net.ConnectivityManager.CONNECTIVITY_ACTION;
 import static android.net.ConnectivityManager.EXTRA_NETWORK_INFO;
 import static android.net.ConnectivityManager.EXTRA_NETWORK_TYPE;
+import static android.net.ConnectivityManager.FIREWALL_CHAIN_LOCKDOWN_VPN;
+import static android.net.ConnectivityManager.FIREWALL_RULE_ALLOW;
+import static android.net.ConnectivityManager.FIREWALL_RULE_DENY;
 import static android.net.ConnectivityManager.PROFILE_NETWORK_PREFERENCE_DEFAULT;
 import static android.net.ConnectivityManager.PROFILE_NETWORK_PREFERENCE_ENTERPRISE;
 import static android.net.ConnectivityManager.PROFILE_NETWORK_PREFERENCE_ENTERPRISE_NO_FALLBACK;
@@ -9502,6 +9505,46 @@
         b2.expectBroadcast();
     }
 
+    @Test
+    public void testLockdownSetFirewallUidRule() throws Exception {
+        // For ConnectivityService#setAlwaysOnVpnPackage.
+        mServiceContext.setPermission(
+                Manifest.permission.CONTROL_ALWAYS_ON_VPN, PERMISSION_GRANTED);
+        // Needed to call Vpn#setAlwaysOnPackage.
+        mServiceContext.setPermission(Manifest.permission.CONTROL_VPN, PERMISSION_GRANTED);
+        // Needed to call Vpn#isAlwaysOnPackageSupported.
+        mServiceContext.setPermission(NETWORK_SETTINGS, PERMISSION_GRANTED);
+
+        // Enable Lockdown
+        final ArrayList<String> allowList = new ArrayList<>();
+        mVpnManagerService.setAlwaysOnVpnPackage(PRIMARY_USER, ALWAYS_ON_PACKAGE,
+                true /* lockdown */, allowList);
+        waitForIdle();
+
+        // Lockdown rule is set to apps uids
+        verify(mBpfNetMaps).setUidRule(
+                eq(FIREWALL_CHAIN_LOCKDOWN_VPN), eq(APP1_UID), eq(FIREWALL_RULE_DENY));
+        verify(mBpfNetMaps).setUidRule(
+                eq(FIREWALL_CHAIN_LOCKDOWN_VPN), eq(APP2_UID), eq(FIREWALL_RULE_DENY));
+
+        reset(mBpfNetMaps);
+
+        // Disable lockdown
+        mVpnManagerService.setAlwaysOnVpnPackage(PRIMARY_USER, null, false /* lockdown */,
+                allowList);
+        waitForIdle();
+
+        // Lockdown rule is removed from apps uids
+        verify(mBpfNetMaps).setUidRule(
+                eq(FIREWALL_CHAIN_LOCKDOWN_VPN), eq(APP1_UID), eq(FIREWALL_RULE_ALLOW));
+        verify(mBpfNetMaps).setUidRule(
+                eq(FIREWALL_CHAIN_LOCKDOWN_VPN), eq(APP2_UID), eq(FIREWALL_RULE_ALLOW));
+
+        // Interface rules are not changed by Lockdown mode enable/disable
+        verify(mBpfNetMaps, never()).addUidInterfaceRules(any(), any());
+        verify(mBpfNetMaps, never()).removeUidInterfaceRules(any());
+    }
+
     /**
      * Test mutable and requestable network capabilities such as
      * {@link NetworkCapabilities#NET_CAPABILITY_TRUSTED} and
@@ -10373,7 +10416,7 @@
         verify(mBpfNetMaps, times(2)).addUidInterfaceRules(eq("tun0"), uidCaptor.capture());
         assertContainsExactly(uidCaptor.getAllValues().get(0), APP1_UID, APP2_UID);
         assertContainsExactly(uidCaptor.getAllValues().get(1), APP1_UID, APP2_UID);
-        assertTrue(mService.mPermissionMonitor.getVpnUidRanges("tun0").equals(vpnRange));
+        assertTrue(mService.mPermissionMonitor.getVpnInterfaceUidRanges("tun0").equals(vpnRange));
 
         mMockVpn.disconnect();
         waitForIdle();
@@ -10381,11 +10424,11 @@
         // Disconnected VPN should have interface rules removed
         verify(mBpfNetMaps).removeUidInterfaceRules(uidCaptor.capture());
         assertContainsExactly(uidCaptor.getValue(), APP1_UID, APP2_UID);
-        assertNull(mService.mPermissionMonitor.getVpnUidRanges("tun0"));
+        assertNull(mService.mPermissionMonitor.getVpnInterfaceUidRanges("tun0"));
     }
 
     @Test
-    public void testLegacyVpnDoesNotResultInInterfaceFilteringRule() throws Exception {
+    public void testLegacyVpnSetInterfaceFilteringRuleWithWildcard() throws Exception {
         LinkProperties lp = new LinkProperties();
         lp.setInterfaceName("tun0");
         lp.addRoute(new RouteInfo(new IpPrefix(Inet6Address.ANY, 0), null));
@@ -10395,13 +10438,29 @@
         mMockVpn.establish(lp, Process.SYSTEM_UID, vpnRange);
         assertVpnUidRangesUpdated(true, vpnRange, Process.SYSTEM_UID);
 
-        // Legacy VPN should not have interface rules set up
-        verify(mBpfNetMaps, never()).addUidInterfaceRules(any(), any());
+        // A connected Legacy VPN should have interface rules with null interface.
+        // Null Interface is a wildcard and this accepts traffic from all the interfaces.
+        // There are two expected invocations, one during the VPN initial connection,
+        // one during the VPN LinkProperties update.
+        ArgumentCaptor<int[]> uidCaptor = ArgumentCaptor.forClass(int[].class);
+        verify(mBpfNetMaps, times(2)).addUidInterfaceRules(
+                eq(null) /* iface */, uidCaptor.capture());
+        assertContainsExactly(uidCaptor.getAllValues().get(0), APP1_UID, APP2_UID, VPN_UID);
+        assertContainsExactly(uidCaptor.getAllValues().get(1), APP1_UID, APP2_UID, VPN_UID);
+        assertEquals(mService.mPermissionMonitor.getVpnInterfaceUidRanges(null /* iface */),
+                vpnRange);
+
+        mMockVpn.disconnect();
+        waitForIdle();
+
+        // Disconnected VPN should have interface rules removed
+        verify(mBpfNetMaps).removeUidInterfaceRules(uidCaptor.capture());
+        assertContainsExactly(uidCaptor.getValue(), APP1_UID, APP2_UID, VPN_UID);
+        assertNull(mService.mPermissionMonitor.getVpnInterfaceUidRanges(null /* iface */));
     }
 
     @Test
-    public void testLocalIpv4OnlyVpnDoesNotResultInInterfaceFilteringRule()
-            throws Exception {
+    public void testLocalIpv4OnlyVpnSetInterfaceFilteringRuleWithWildcard() throws Exception {
         LinkProperties lp = new LinkProperties();
         lp.setInterfaceName("tun0");
         lp.addRoute(new RouteInfo(new IpPrefix("192.0.2.0/24"), null, "tun0"));
@@ -10412,7 +10471,25 @@
         assertVpnUidRangesUpdated(true, vpnRange, Process.SYSTEM_UID);
 
         // IPv6 unreachable route should not be misinterpreted as a default route
-        verify(mBpfNetMaps, never()).addUidInterfaceRules(any(), any());
+        // A connected VPN should have interface rules with null interface.
+        // Null Interface is a wildcard and this accepts traffic from all the interfaces.
+        // There are two expected invocations, one during the VPN initial connection,
+        // one during the VPN LinkProperties update.
+        ArgumentCaptor<int[]> uidCaptor = ArgumentCaptor.forClass(int[].class);
+        verify(mBpfNetMaps, times(2)).addUidInterfaceRules(
+                eq(null) /* iface */, uidCaptor.capture());
+        assertContainsExactly(uidCaptor.getAllValues().get(0), APP1_UID, APP2_UID, VPN_UID);
+        assertContainsExactly(uidCaptor.getAllValues().get(1), APP1_UID, APP2_UID, VPN_UID);
+        assertEquals(mService.mPermissionMonitor.getVpnInterfaceUidRanges(null /* iface */),
+                vpnRange);
+
+        mMockVpn.disconnect();
+        waitForIdle();
+
+        // Disconnected VPN should have interface rules removed
+        verify(mBpfNetMaps).removeUidInterfaceRules(uidCaptor.capture());
+        assertContainsExactly(uidCaptor.getValue(), APP1_UID, APP2_UID, VPN_UID);
+        assertNull(mService.mPermissionMonitor.getVpnInterfaceUidRanges(null /* iface */));
     }
 
     @Test
diff --git a/tests/unit/java/com/android/server/connectivity/PermissionMonitorTest.java b/tests/unit/java/com/android/server/connectivity/PermissionMonitorTest.java
index fb821c3..ecd17ba 100644
--- a/tests/unit/java/com/android/server/connectivity/PermissionMonitorTest.java
+++ b/tests/unit/java/com/android/server/connectivity/PermissionMonitorTest.java
@@ -30,6 +30,9 @@
 import static android.content.pm.PackageInfo.REQUESTED_PERMISSION_REQUIRED;
 import static android.content.pm.PackageManager.GET_PERMISSIONS;
 import static android.content.pm.PackageManager.MATCH_ANY_USER;
+import static android.net.ConnectivityManager.FIREWALL_CHAIN_LOCKDOWN_VPN;
+import static android.net.ConnectivityManager.FIREWALL_RULE_ALLOW;
+import static android.net.ConnectivityManager.FIREWALL_RULE_DENY;
 import static android.net.ConnectivitySettingsManager.UIDS_ALLOWED_ON_RESTRICTED_NETWORKS;
 import static android.net.INetd.PERMISSION_INTERNET;
 import static android.net.INetd.PERMISSION_NETWORK;
@@ -761,8 +764,8 @@
                 MOCK_APPID1);
     }
 
-    @Test
-    public void testUidFilteringDuringVpnConnectDisconnectAndUidUpdates() throws Exception {
+    private void doTestuidFilteringDuringVpnConnectDisconnectAndUidUpdates(@Nullable String ifName)
+            throws Exception {
         doReturn(List.of(buildPackageInfo(SYSTEM_PACKAGE1, SYSTEM_APP_UID11, CHANGE_NETWORK_STATE,
                         CONNECTIVITY_USE_RESTRICTED_NETWORKS),
                 buildPackageInfo(MOCK_PACKAGE1, MOCK_UID11),
@@ -778,8 +781,8 @@
         final Set<UidRange> vpnRange2 = Set.of(new UidRange(MOCK_UID12, MOCK_UID12));
 
         // When VPN is connected, expect a rule to be set up for user app MOCK_UID11
-        mPermissionMonitor.onVpnUidRangesAdded("tun0", vpnRange1, VPN_UID);
-        verify(mBpfNetMaps).addUidInterfaceRules(eq("tun0"), aryEq(new int[]{MOCK_UID11}));
+        mPermissionMonitor.onVpnUidRangesAdded(ifName, vpnRange1, VPN_UID);
+        verify(mBpfNetMaps).addUidInterfaceRules(eq(ifName), aryEq(new int[]{MOCK_UID11}));
 
         reset(mBpfNetMaps);
 
@@ -787,27 +790,38 @@
         mPermissionMonitor.onPackageRemoved(MOCK_PACKAGE1, MOCK_UID11);
         verify(mBpfNetMaps).removeUidInterfaceRules(aryEq(new int[]{MOCK_UID11}));
         mPermissionMonitor.onPackageAdded(MOCK_PACKAGE1, MOCK_UID11);
-        verify(mBpfNetMaps).addUidInterfaceRules(eq("tun0"), aryEq(new int[]{MOCK_UID11}));
+        verify(mBpfNetMaps).addUidInterfaceRules(eq(ifName), aryEq(new int[]{MOCK_UID11}));
 
         reset(mBpfNetMaps);
 
         // During VPN uid update (vpnRange1 -> vpnRange2), ConnectivityService first deletes the
         // old UID rules then adds the new ones. Expect netd to be updated
-        mPermissionMonitor.onVpnUidRangesRemoved("tun0", vpnRange1, VPN_UID);
+        mPermissionMonitor.onVpnUidRangesRemoved(ifName, vpnRange1, VPN_UID);
         verify(mBpfNetMaps).removeUidInterfaceRules(aryEq(new int[] {MOCK_UID11}));
-        mPermissionMonitor.onVpnUidRangesAdded("tun0", vpnRange2, VPN_UID);
-        verify(mBpfNetMaps).addUidInterfaceRules(eq("tun0"), aryEq(new int[]{MOCK_UID12}));
+        mPermissionMonitor.onVpnUidRangesAdded(ifName, vpnRange2, VPN_UID);
+        verify(mBpfNetMaps).addUidInterfaceRules(eq(ifName), aryEq(new int[]{MOCK_UID12}));
 
         reset(mBpfNetMaps);
 
         // When VPN is disconnected, expect rules to be torn down
-        mPermissionMonitor.onVpnUidRangesRemoved("tun0", vpnRange2, VPN_UID);
+        mPermissionMonitor.onVpnUidRangesRemoved(ifName, vpnRange2, VPN_UID);
         verify(mBpfNetMaps).removeUidInterfaceRules(aryEq(new int[] {MOCK_UID12}));
-        assertNull(mPermissionMonitor.getVpnUidRanges("tun0"));
+        assertNull(mPermissionMonitor.getVpnInterfaceUidRanges(ifName));
     }
 
     @Test
-    public void testUidFilteringDuringPackageInstallAndUninstall() throws Exception {
+    public void testUidFilteringDuringVpnConnectDisconnectAndUidUpdates() throws Exception {
+        doTestuidFilteringDuringVpnConnectDisconnectAndUidUpdates("tun0");
+    }
+
+    @Test
+    public void testUidFilteringDuringVpnConnectDisconnectAndUidUpdatesWithWildcard()
+            throws Exception {
+        doTestuidFilteringDuringVpnConnectDisconnectAndUidUpdates(null /* ifName */);
+    }
+
+    private void doTestUidFilteringDuringPackageInstallAndUninstall(@Nullable String ifName) throws
+            Exception {
         doReturn(List.of(buildPackageInfo(SYSTEM_PACKAGE1, SYSTEM_APP_UID11, CHANGE_NETWORK_STATE,
                         NETWORK_STACK, CONNECTIVITY_USE_RESTRICTED_NETWORKS),
                 buildPackageInfo(SYSTEM_PACKAGE2, VPN_UID)))
@@ -818,12 +832,12 @@
         mPermissionMonitor.startMonitoring();
         final Set<UidRange> vpnRange = Set.of(UidRange.createForUser(MOCK_USER1),
                 UidRange.createForUser(MOCK_USER2));
-        mPermissionMonitor.onVpnUidRangesAdded("tun0", vpnRange, VPN_UID);
+        mPermissionMonitor.onVpnUidRangesAdded(ifName, vpnRange, VPN_UID);
 
         // Newly-installed package should have uid rules added
         addPackageForUsers(new UserHandle[]{MOCK_USER1, MOCK_USER2}, MOCK_PACKAGE1, MOCK_APPID1);
-        verify(mBpfNetMaps).addUidInterfaceRules(eq("tun0"), aryEq(new int[]{MOCK_UID11}));
-        verify(mBpfNetMaps).addUidInterfaceRules(eq("tun0"), aryEq(new int[]{MOCK_UID21}));
+        verify(mBpfNetMaps).addUidInterfaceRules(eq(ifName), aryEq(new int[]{MOCK_UID11}));
+        verify(mBpfNetMaps).addUidInterfaceRules(eq(ifName), aryEq(new int[]{MOCK_UID21}));
 
         // Removed package should have its uid rules removed
         mPermissionMonitor.onPackageRemoved(MOCK_PACKAGE1, MOCK_UID11);
@@ -831,6 +845,168 @@
         verify(mBpfNetMaps, never()).removeUidInterfaceRules(aryEq(new int[]{MOCK_UID21}));
     }
 
+    @Test
+    public void testUidFilteringDuringPackageInstallAndUninstall() throws Exception {
+        doTestUidFilteringDuringPackageInstallAndUninstall("tun0");
+    }
+
+    @Test
+    public void testUidFilteringDuringPackageInstallAndUninstallWithWildcard() throws Exception {
+        doTestUidFilteringDuringPackageInstallAndUninstall(null /* ifName */);
+    }
+
+    @Test
+    public void testLockdownUidFilteringWithLockdownEnableDisable() {
+        doReturn(List.of(buildPackageInfo(SYSTEM_PACKAGE1, SYSTEM_APP_UID11, CHANGE_NETWORK_STATE,
+                        CONNECTIVITY_USE_RESTRICTED_NETWORKS),
+                buildPackageInfo(MOCK_PACKAGE1, MOCK_UID11),
+                buildPackageInfo(MOCK_PACKAGE2, MOCK_UID12),
+                buildPackageInfo(SYSTEM_PACKAGE2, VPN_UID)))
+                .when(mPackageManager).getInstalledPackagesAsUser(eq(GET_PERMISSIONS), anyInt());
+        mPermissionMonitor.startMonitoring();
+        // Every app on user 0 except MOCK_UID12 are under VPN.
+        final UidRange[] vpnRange1 = {
+                new UidRange(0, MOCK_UID12 - 1),
+                new UidRange(MOCK_UID12 + 1, UserHandle.PER_USER_RANGE - 1)
+        };
+
+        // Add Lockdown uid range, expect a rule to be set up for user app MOCK_UID11
+        mPermissionMonitor.updateVpnLockdownUidRanges(true /* add */, vpnRange1);
+        verify(mBpfNetMaps)
+                .setUidRule(
+                        eq(FIREWALL_CHAIN_LOCKDOWN_VPN), eq(MOCK_UID11),
+                        eq(FIREWALL_RULE_DENY));
+        assertEquals(mPermissionMonitor.getVpnLockdownUidRanges(), Set.of(vpnRange1));
+
+        reset(mBpfNetMaps);
+
+        // Remove Lockdown uid range, expect rules to be torn down
+        mPermissionMonitor.updateVpnLockdownUidRanges(false /* false */, vpnRange1);
+        verify(mBpfNetMaps)
+                .setUidRule(eq(FIREWALL_CHAIN_LOCKDOWN_VPN), eq(MOCK_UID11),
+                        eq(FIREWALL_RULE_ALLOW));
+        assertTrue(mPermissionMonitor.getVpnLockdownUidRanges().isEmpty());
+    }
+
+    @Test
+    public void testLockdownUidFilteringWithLockdownEnableDisableWithMultiAdd() {
+        doReturn(List.of(buildPackageInfo(SYSTEM_PACKAGE1, SYSTEM_APP_UID11, CHANGE_NETWORK_STATE,
+                        CONNECTIVITY_USE_RESTRICTED_NETWORKS),
+                buildPackageInfo(MOCK_PACKAGE1, MOCK_UID11),
+                buildPackageInfo(SYSTEM_PACKAGE2, VPN_UID)))
+                .when(mPackageManager).getInstalledPackagesAsUser(eq(GET_PERMISSIONS), anyInt());
+        mPermissionMonitor.startMonitoring();
+        // MOCK_UID11 is under VPN.
+        final UidRange range = new UidRange(MOCK_UID11, MOCK_UID11);
+        final UidRange[] vpnRange = {range};
+
+        // Add Lockdown uid range at 1st time, expect a rule to be set up
+        mPermissionMonitor.updateVpnLockdownUidRanges(true /* add */, vpnRange);
+        verify(mBpfNetMaps)
+                .setUidRule(eq(FIREWALL_CHAIN_LOCKDOWN_VPN), eq(MOCK_UID11),
+                        eq(FIREWALL_RULE_DENY));
+        assertEquals(mPermissionMonitor.getVpnLockdownUidRanges(), Set.of(vpnRange));
+
+        reset(mBpfNetMaps);
+
+        // Add Lockdown uid range at 2nd time, expect a rule not to be set up because the uid
+        // already has the rule
+        mPermissionMonitor.updateVpnLockdownUidRanges(true /* add */, vpnRange);
+        verify(mBpfNetMaps, never()).setUidRule(anyInt(), anyInt(), anyInt());
+        assertEquals(mPermissionMonitor.getVpnLockdownUidRanges(), Set.of(vpnRange));
+
+        reset(mBpfNetMaps);
+
+        // Remove Lockdown uid range at 1st time, expect a rule not to be torn down because we added
+        // the range 2 times.
+        mPermissionMonitor.updateVpnLockdownUidRanges(false /* false */, vpnRange);
+        verify(mBpfNetMaps, never()).setUidRule(anyInt(), anyInt(), anyInt());
+        assertEquals(mPermissionMonitor.getVpnLockdownUidRanges(), Set.of(vpnRange));
+
+        reset(mBpfNetMaps);
+
+        // Remove Lockdown uid range at 2nd time, expect a rule to be torn down because we added
+        // twice and we removed twice.
+        mPermissionMonitor.updateVpnLockdownUidRanges(false /* false */, vpnRange);
+        verify(mBpfNetMaps)
+                .setUidRule(eq(FIREWALL_CHAIN_LOCKDOWN_VPN), eq(MOCK_UID11),
+                        eq(FIREWALL_RULE_ALLOW));
+        assertTrue(mPermissionMonitor.getVpnLockdownUidRanges().isEmpty());
+    }
+
+    @Test
+    public void testLockdownUidFilteringWithLockdownEnableDisableWithDuplicates() {
+        doReturn(List.of(buildPackageInfo(SYSTEM_PACKAGE1, SYSTEM_APP_UID11, CHANGE_NETWORK_STATE,
+                        CONNECTIVITY_USE_RESTRICTED_NETWORKS),
+                buildPackageInfo(MOCK_PACKAGE1, MOCK_UID11),
+                buildPackageInfo(SYSTEM_PACKAGE2, VPN_UID)))
+                .when(mPackageManager).getInstalledPackagesAsUser(eq(GET_PERMISSIONS), anyInt());
+        mPermissionMonitor.startMonitoring();
+        // MOCK_UID11 is under VPN.
+        final UidRange range = new UidRange(MOCK_UID11, MOCK_UID11);
+        final UidRange[] vpnRangeDuplicates = {range, range};
+        final UidRange[] vpnRange = {range};
+
+        // Add Lockdown uid ranges which contains duplicated uid ranges
+        mPermissionMonitor.updateVpnLockdownUidRanges(true /* add */, vpnRangeDuplicates);
+        verify(mBpfNetMaps)
+                .setUidRule(eq(FIREWALL_CHAIN_LOCKDOWN_VPN), eq(MOCK_UID11),
+                        eq(FIREWALL_RULE_DENY));
+        assertEquals(mPermissionMonitor.getVpnLockdownUidRanges(), Set.of(vpnRange));
+
+        reset(mBpfNetMaps);
+
+        // Remove Lockdown uid range at 1st time, expect a rule not to be torn down because uid
+        // ranges we added contains duplicated uid ranges.
+        mPermissionMonitor.updateVpnLockdownUidRanges(false /* false */, vpnRange);
+        verify(mBpfNetMaps, never()).setUidRule(anyInt(), anyInt(), anyInt());
+        assertEquals(mPermissionMonitor.getVpnLockdownUidRanges(), Set.of(vpnRange));
+
+        reset(mBpfNetMaps);
+
+        // Remove Lockdown uid range at 2nd time, expect a rule to be torn down.
+        mPermissionMonitor.updateVpnLockdownUidRanges(false /* false */, vpnRange);
+        verify(mBpfNetMaps)
+                .setUidRule(eq(FIREWALL_CHAIN_LOCKDOWN_VPN), eq(MOCK_UID11),
+                        eq(FIREWALL_RULE_ALLOW));
+        assertTrue(mPermissionMonitor.getVpnLockdownUidRanges().isEmpty());
+    }
+
+    @Test
+    public void testLockdownUidFilteringWithInstallAndUnInstall() {
+        doReturn(List.of(buildPackageInfo(SYSTEM_PACKAGE1, SYSTEM_APP_UID11, CHANGE_NETWORK_STATE,
+                        NETWORK_STACK, CONNECTIVITY_USE_RESTRICTED_NETWORKS),
+                buildPackageInfo(SYSTEM_PACKAGE2, VPN_UID)))
+                .when(mPackageManager).getInstalledPackagesAsUser(eq(GET_PERMISSIONS), anyInt());
+        doReturn(List.of(MOCK_USER1, MOCK_USER2)).when(mUserManager).getUserHandles(eq(true));
+
+        mPermissionMonitor.startMonitoring();
+        final UidRange[] vpnRange = {
+                UidRange.createForUser(MOCK_USER1),
+                UidRange.createForUser(MOCK_USER2)
+        };
+        mPermissionMonitor.updateVpnLockdownUidRanges(true /* add */, vpnRange);
+
+        // Installing package should add Lockdown rules
+        addPackageForUsers(new UserHandle[]{MOCK_USER1, MOCK_USER2}, MOCK_PACKAGE1, MOCK_APPID1);
+        verify(mBpfNetMaps)
+                .setUidRule(eq(FIREWALL_CHAIN_LOCKDOWN_VPN), eq(MOCK_UID11),
+                        eq(FIREWALL_RULE_DENY));
+        verify(mBpfNetMaps)
+                .setUidRule(eq(FIREWALL_CHAIN_LOCKDOWN_VPN), eq(MOCK_UID21),
+                        eq(FIREWALL_RULE_DENY));
+
+        reset(mBpfNetMaps);
+
+        // Uninstalling package should remove Lockdown rules
+        mPermissionMonitor.onPackageRemoved(MOCK_PACKAGE1, MOCK_UID11);
+        verify(mBpfNetMaps)
+                .setUidRule(eq(FIREWALL_CHAIN_LOCKDOWN_VPN), eq(MOCK_UID11),
+                        eq(FIREWALL_RULE_ALLOW));
+        verify(mBpfNetMaps, never())
+                .setUidRule(eq(FIREWALL_CHAIN_LOCKDOWN_VPN), eq(MOCK_UID21),
+                        eq(FIREWALL_RULE_ALLOW));
+    }
 
     // Normal package add/remove operations will trigger multiple intent for uids corresponding to
     // each user. To simulate generic package operations, the onPackageAdded/Removed will need to be