diff --git a/core/java/android/net/NetworkCapabilities.java b/core/java/android/net/NetworkCapabilities.java
index 99375f8..dfd7089 100644
--- a/core/java/android/net/NetworkCapabilities.java
+++ b/core/java/android/net/NetworkCapabilities.java
@@ -822,6 +822,11 @@
         mEstablishingVpnAppUid = uid;
     }
 
+    /** @hide */
+    public int getEstablishingVpnAppUid() {
+        return mEstablishingVpnAppUid;
+    }
+
     /**
      * Value indicating that link bandwidth is unspecified.
      * @hide
diff --git a/core/java/android/net/TestNetworkManager.java b/core/java/android/net/TestNetworkManager.java
index cfda460..e274005 100644
--- a/core/java/android/net/TestNetworkManager.java
+++ b/core/java/android/net/TestNetworkManager.java
@@ -85,4 +85,21 @@
             throw e.rethrowFromSystemServer();
         }
     }
+
+    /**
+     * Create a tap interface for testing purposes
+     *
+     * @return A ParcelFileDescriptor of the underlying TAP interface. Close this to tear down the
+     *     TAP interface.
+     * @hide
+     */
+    @TestApi
+    public TestNetworkInterface createTapInterface() {
+        try {
+            return mService.createTapInterface();
+        } catch (RemoteException e) {
+            throw e.rethrowFromSystemServer();
+        }
+    }
+
 }
diff --git a/core/java/android/net/UidRange.java b/core/java/android/net/UidRange.java
index fa0eeb9..a1ac960 100644
--- a/core/java/android/net/UidRange.java
+++ b/core/java/android/net/UidRange.java
@@ -21,6 +21,8 @@
 import android.os.Parcel;
 import android.os.Parcelable;
 
+import java.util.Collection;
+
 /**
  * An inclusive range of UIDs.
  *
@@ -42,10 +44,16 @@
         return new UidRange(userId * PER_USER_RANGE, (userId + 1) * PER_USER_RANGE - 1);
     }
 
+    /** Returns the smallest user Id which is contained in this UidRange */
     public int getStartUser() {
         return start / PER_USER_RANGE;
     }
 
+    /** Returns the largest user Id which is contained in this UidRange */
+    public int getEndUser() {
+        return stop / PER_USER_RANGE;
+    }
+
     public boolean contains(int uid) {
         return start <= uid && uid <= stop;
     }
@@ -117,4 +125,23 @@
                 return new UidRange[size];
             }
     };
+
+    /**
+     * Returns whether any of the UidRange in the collection contains the specified uid
+     *
+     * @param ranges The collection of UidRange to check
+     * @param uid the uid in question
+     * @return {@code true} if the uid is contained within the ranges, {@code false} otherwise
+     *
+     * @see UidRange#contains(int)
+     */
+    public static boolean containsUid(Collection<UidRange> ranges, int uid) {
+        if (ranges == null) return false;
+        for (UidRange range : ranges) {
+            if (range.contains(uid)) {
+                return true;
+            }
+        }
+        return false;
+    }
 }
diff --git a/services/core/java/com/android/server/ConnectivityService.java b/services/core/java/com/android/server/ConnectivityService.java
index 524548f..c1aff75 100644
--- a/services/core/java/com/android/server/ConnectivityService.java
+++ b/services/core/java/com/android/server/ConnectivityService.java
@@ -47,6 +47,7 @@
 
 import static com.android.internal.util.Preconditions.checkNotNull;
 
+import android.annotation.NonNull;
 import android.annotation.Nullable;
 import android.app.BroadcastOptions;
 import android.app.NotificationManager;
@@ -276,7 +277,8 @@
 
     private Tethering mTethering;
 
-    private final PermissionMonitor mPermissionMonitor;
+    @VisibleForTesting
+    protected final PermissionMonitor mPermissionMonitor;
 
     private KeyStore mKeyStore;
 
@@ -829,13 +831,13 @@
     public ConnectivityService(Context context, INetworkManagementService netManager,
             INetworkStatsService statsService, INetworkPolicyManager policyManager) {
         this(context, netManager, statsService, policyManager,
-            getDnsResolver(), new IpConnectivityLog());
+            getDnsResolver(), new IpConnectivityLog(), NetdService.getInstance());
     }
 
     @VisibleForTesting
     protected ConnectivityService(Context context, INetworkManagementService netManager,
             INetworkStatsService statsService, INetworkPolicyManager policyManager,
-            IDnsResolver dnsresolver, IpConnectivityLog logger) {
+            IDnsResolver dnsresolver, IpConnectivityLog logger, INetd netd) {
         if (DBG) log("ConnectivityService starting up");
 
         mSystemProperties = getSystemProperties();
@@ -875,7 +877,7 @@
         mDnsResolver = checkNotNull(dnsresolver, "missing IDnsResolver");
         mProxyTracker = makeProxyTracker();
 
-        mNetd = NetdService.getInstance();
+        mNetd = netd;
         mKeyStore = KeyStore.getInstance();
         mTelephonyManager = (TelephonyManager) mContext.getSystemService(Context.TELEPHONY_SERVICE);
 
@@ -961,7 +963,7 @@
 
         mTethering = makeTethering();
 
-        mPermissionMonitor = new PermissionMonitor(mContext, mNMS, mNetd);
+        mPermissionMonitor = new PermissionMonitor(mContext, mNetd);
 
         // Set up the listener for user state for creating user VPNs.
         // Should run on mHandler to avoid any races.
@@ -2441,6 +2443,13 @@
         pw.println("NetworkStackClient logs:");
         pw.increaseIndent();
         NetworkStackClient.getInstance().dump(pw);
+        pw.decreaseIndent();
+
+        pw.println();
+        pw.println("Permission Monitor:");
+        pw.increaseIndent();
+        mPermissionMonitor.dump(pw);
+        pw.decreaseIndent();
     }
 
     private void dumpNetworks(IndentingPrintWriter pw) {
@@ -5465,6 +5474,11 @@
         networkAgent.clatd.fixupLinkProperties(oldLp, newLp);
 
         updateInterfaces(newLp, oldLp, netId, networkAgent.networkCapabilities);
+
+        // update filtering rules, need to happen after the interface update so netd knows about the
+        // new interface (the interface name -> index map becomes initialized)
+        updateVpnFiltering(newLp, oldLp, networkAgent);
+
         updateMtu(newLp, oldLp);
         // TODO - figure out what to do for clat
 //        for (LinkProperties lp : newLp.getStackedLinks()) {
@@ -5630,6 +5644,37 @@
         }
     }
 
+    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);
+
+        if (!wasFiltering && !needsFiltering) {
+            // Nothing to do.
+            return;
+        }
+
+        if (Objects.equals(oldIface, newIface) && (wasFiltering == needsFiltering)) {
+            // Nothing changed.
+            return;
+        }
+
+        final Set<UidRange> ranges = nai.networkCapabilities.getUids();
+        final int vpnAppUid = nai.networkCapabilities.getEstablishingVpnAppUid();
+        // 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 whitelisted interfaces so here new rules can be added before the
+        // old rules are being removed.
+        if (wasFiltering) {
+            mPermissionMonitor.onVpnUidRangesRemoved(oldIface, ranges, vpnAppUid);
+        }
+        if (needsFiltering) {
+            mPermissionMonitor.onVpnUidRangesAdded(newIface, ranges, vpnAppUid);
+        }
+    }
+
     private int getNetworkPermission(NetworkCapabilities nc) {
         if (!nc.hasCapability(NET_CAPABILITY_NOT_RESTRICTED)) {
             return INetd.PERMISSION_SYSTEM;
@@ -5772,6 +5817,34 @@
         }
     }
 
+    /**
+     * Returns whether VPN isolation (ingress interface filtering) should be applied on the given
+     * network.
+     *
+     * 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
+     *  1. the network is an app VPN (not legacy VPN)
+     *  2. the VPN does not allow bypass
+     *  3. the VPN is fully-routed
+     *  4. the VPN interface is non-null
+     *
+     * @See INetd#firewallAddUidInterfaceRules
+     * @See INetd#firewallRemoveUidInterfaceRules
+     */
+    private boolean requiresVpnIsolation(@NonNull NetworkAgentInfo nai, NetworkCapabilities nc,
+            LinkProperties lp) {
+        if (nc == null || lp == null) return false;
+        return nai.isVPN()
+                && !nai.networkMisc.allowBypass
+                && nc.getEstablishingVpnAppUid() != Process.SYSTEM_UID
+                && lp.getInterfaceName() != null
+                && (lp.hasIPv4DefaultRoute() || lp.hasIPv6DefaultRoute());
+    }
+
     private void updateUids(NetworkAgentInfo nai, NetworkCapabilities prevNc,
             NetworkCapabilities newNc) {
         Set<UidRange> prevRanges = null == prevNc ? null : prevNc.getUids();
@@ -5784,6 +5857,12 @@
         newRanges.removeAll(prevRangesCopy);
 
         try {
+            // When updating the VPN uid routing rules, add the new range first then remove the old
+            // range. If old range were removed first, there would be a window between the old
+            // range being removed and the new range being added, during which UIDs contained
+            // in both ranges are not subject to any VPN routing rules. Adding new range before
+            // removing old range works because, unlike the filtering rules below, it's possible to
+            // add duplicate UID routing rules.
             if (!newRanges.isEmpty()) {
                 final UidRange[] addedRangesArray = new UidRange[newRanges.size()];
                 newRanges.toArray(addedRangesArray);
@@ -5794,9 +5873,31 @@
                 prevRanges.toArray(removedRangesArray);
                 mNMS.removeVpnUidRanges(nai.network.netId, removedRangesArray);
             }
+            final boolean wasFiltering = requiresVpnIsolation(nai, prevNc, nai.linkProperties);
+            final boolean shouldFilter = requiresVpnIsolation(nai, newNc, nai.linkProperties);
+            final String iface = nai.linkProperties.getInterfaceName();
+            // 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 invidiual UIDs. For example
+            // the UIDs might be updated from [0, 99999] to ([0, 10012], [10014, 99999]) which means
+            // prevRanges = [0, 99999] while newRanges = [0, 10012], [10014, 99999]. If prevRanges
+            // were added first and then newRanges got removed later, there would be only one uid
+            // 10013 left. A consequence of removing old ranges before adding new ranges is that
+            // there is now a window of opportunity when the UIDs are not subject to any filtering.
+            // Note that this is in contrast with the (more robust) update of VPN routing rules
+            // 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.
+            if (wasFiltering && !prevRanges.isEmpty()) {
+                mPermissionMonitor.onVpnUidRangesRemoved(iface, prevRanges,
+                        prevNc.getEstablishingVpnAppUid());
+            }
+            if (shouldFilter && !newRanges.isEmpty()) {
+                mPermissionMonitor.onVpnUidRangesAdded(iface, newRanges,
+                        newNc.getEstablishingVpnAppUid());
+            }
         } catch (Exception e) {
             // Never crash!
-            loge("Exception in updateUids: " + e);
+            loge("Exception in updateUids: ", e);
         }
     }
 
diff --git a/services/core/java/com/android/server/TestNetworkService.java b/services/core/java/com/android/server/TestNetworkService.java
index bd20a24..40bf7bc 100644
--- a/services/core/java/com/android/server/TestNetworkService.java
+++ b/services/core/java/com/android/server/TestNetworkService.java
@@ -60,6 +60,7 @@
     @NonNull private static final String TAG = TestNetworkService.class.getSimpleName();
     @NonNull private static final String TEST_NETWORK_TYPE = "TEST_NETWORK";
     @NonNull private static final String TEST_TUN_PREFIX = "testtun";
+    @NonNull private static final String TEST_TAP_PREFIX = "testtap";
     @NonNull private static final AtomicInteger sTestTunIndex = new AtomicInteger();
 
     @NonNull private final Context mContext;
@@ -70,7 +71,7 @@
     @NonNull private final Handler mHandler;
 
     // Native method stubs
-    private static native int jniCreateTun(@NonNull String iface);
+    private static native int jniCreateTunTap(boolean isTun, @NonNull String iface);
 
     @VisibleForTesting
     protected TestNetworkService(
@@ -85,23 +86,23 @@
     }
 
     /**
-     * Create a TUN interface with the given interface name and link addresses
+     * Create a TUN or TAP interface with the given interface name and link addresses
      *
-     * <p>This method will return the FileDescriptor to the TUN interface. Close it to tear down the
-     * TUN interface.
+     * <p>This method will return the FileDescriptor to the interface. Close it to tear down the
+     * interface.
      */
-    @Override
-    public TestNetworkInterface createTunInterface(@NonNull LinkAddress[] linkAddrs) {
+    private TestNetworkInterface createInterface(boolean isTun, LinkAddress[] linkAddrs) {
         enforceTestNetworkPermissions(mContext);
 
         checkNotNull(linkAddrs, "missing linkAddrs");
 
-        String iface = TEST_TUN_PREFIX + sTestTunIndex.getAndIncrement();
+        String ifacePrefix = isTun ? TEST_TUN_PREFIX : TEST_TAP_PREFIX;
+        String iface = ifacePrefix + sTestTunIndex.getAndIncrement();
         return Binder.withCleanCallingIdentity(
                 () -> {
                     try {
                         ParcelFileDescriptor tunIntf =
-                                ParcelFileDescriptor.adoptFd(jniCreateTun(iface));
+                                ParcelFileDescriptor.adoptFd(jniCreateTunTap(isTun, iface));
                         for (LinkAddress addr : linkAddrs) {
                             mNetd.interfaceAddAddress(
                                     iface,
@@ -116,6 +117,28 @@
                 });
     }
 
+    /**
+     * Create a TUN interface with the given interface name and link addresses
+     *
+     * <p>This method will return the FileDescriptor to the TUN interface. Close it to tear down the
+     * TUN interface.
+     */
+    @Override
+    public TestNetworkInterface createTunInterface(@NonNull LinkAddress[] linkAddrs) {
+        return createInterface(true, linkAddrs);
+    }
+
+    /**
+     * Create a TAP interface with the given interface name
+     *
+     * <p>This method will return the FileDescriptor to the TAP interface. Close it to tear down the
+     * TAP interface.
+     */
+    @Override
+    public TestNetworkInterface createTapInterface() {
+        return createInterface(false, new LinkAddress[0]);
+    }
+
     // Tracker for TestNetworkAgents
     @GuardedBy("mTestNetworkTracker")
     @NonNull
diff --git a/services/core/java/com/android/server/connectivity/PermissionMonitor.java b/services/core/java/com/android/server/connectivity/PermissionMonitor.java
index b694602..f8582cd 100644
--- a/services/core/java/com/android/server/connectivity/PermissionMonitor.java
+++ b/services/core/java/com/android/server/connectivity/PermissionMonitor.java
@@ -37,22 +37,27 @@
 import android.content.pm.PackageManagerInternal;
 import android.content.pm.UserInfo;
 import android.net.INetd;
+import android.net.UidRange;
 import android.os.Build;
-import android.os.INetworkManagementService;
 import android.os.RemoteException;
+import android.os.ServiceSpecificException;
 import android.os.UserHandle;
 import android.os.UserManager;
+import android.system.OsConstants;
 import android.util.ArraySet;
 import android.util.Log;
 import android.util.SparseArray;
 import android.util.SparseIntArray;
 
+import com.android.internal.annotations.GuardedBy;
 import com.android.internal.annotations.VisibleForTesting;
 import com.android.internal.util.ArrayUtils;
+import com.android.internal.util.IndentingPrintWriter;
 import com.android.server.LocalServices;
 import com.android.server.SystemConfig;
 
 import java.util.ArrayList;
+import java.util.Collection;
 import java.util.HashMap;
 import java.util.HashSet;
 import java.util.List;
@@ -60,6 +65,7 @@
 import java.util.Map.Entry;
 import java.util.Set;
 
+
 /**
  * A utility class to inform Netd of UID permisisons.
  * Does a mass update at boot and then monitors for app install/remove.
@@ -73,18 +79,29 @@
     protected static final Boolean NETWORK = Boolean.FALSE;
     private static final int VERSION_Q = Build.VERSION_CODES.Q;
 
-    private final Context mContext;
     private final PackageManager mPackageManager;
     private final UserManager mUserManager;
-    private final INetworkManagementService mNMS;
     private final INetd mNetd;
 
     // Values are User IDs.
+    @GuardedBy("this")
     private final Set<Integer> mUsers = new HashSet<>();
 
-    // Keys are App IDs. Values are true for SYSTEM permission and false for NETWORK permission.
+    // Keys are app uids. Values are true for SYSTEM permission and false for NETWORK permission.
+    @GuardedBy("this")
     private final Map<Integer, Boolean> mApps = new HashMap<>();
 
+    // Keys are active non-bypassable and fully-routed VPN's interface name, Values are uid ranges
+    // for apps under the VPN
+    @GuardedBy("this")
+    private final Map<String, Set<UidRange>> mVpnUidRanges = new HashMap<>();
+
+    // 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
+    // added/removed.
+    @GuardedBy("this")
+    private final Set<Integer> mAllApps = new HashSet<>();
+
     private class PackageListObserver implements PackageManagerInternal.PackageListObserver {
 
         private int getPermissionForUid(int uid) {
@@ -118,12 +135,10 @@
         }
     }
 
-    public PermissionMonitor(Context context, INetworkManagementService nms, INetd netdService) {
-        mContext = context;
+    public PermissionMonitor(Context context, INetd netd) {
         mPackageManager = context.getPackageManager();
-        mUserManager = UserManager.get(context);
-        mNMS = nms;
-        mNetd = netdService;
+        mUserManager = (UserManager) context.getSystemService(Context.USER_SERVICE);
+        mNetd = netd;
     }
 
     // Intended to be called only once at startup, after the system is ready. Installs a broadcast
@@ -151,6 +166,7 @@
             if (uid < 0) {
                 continue;
             }
+            mAllApps.add(UserHandle.getAppId(uid));
 
             boolean isNetwork = hasNetworkPermission(app);
             boolean hasRestrictedPermission = hasRestrictedNetworkPermission(app);
@@ -270,10 +286,11 @@
         }
     }
 
-    private int[] toIntArray(List<Integer> list) {
+    private int[] toIntArray(Collection<Integer> list) {
         int[] array = new int[list.size()];
-        for (int i = 0; i < list.size(); i++) {
-            array[i] = list.get(i);
+        int i = 0;
+        for (Integer item : list) {
+            array[i++] = item;
         }
         return array;
     }
@@ -289,11 +306,11 @@
         }
         try {
             if (add) {
-                mNMS.setPermission("NETWORK", toIntArray(network));
-                mNMS.setPermission("SYSTEM", toIntArray(system));
+                mNetd.networkSetPermissionForUser(INetd.PERMISSION_NETWORK, toIntArray(network));
+                mNetd.networkSetPermissionForUser(INetd.PERMISSION_SYSTEM, toIntArray(system));
             } else {
-                mNMS.clearPermission(toIntArray(network));
-                mNMS.clearPermission(toIntArray(system));
+                mNetd.networkClearPermissionForUser(toIntArray(network));
+                mNetd.networkClearPermissionForUser(toIntArray(system));
             }
         } catch (RemoteException e) {
             loge("Exception when updating permissions: " + e);
@@ -376,6 +393,19 @@
             apps.put(uid, permission);
             update(mUsers, apps, true);
         }
+
+        // If the newly-installed package falls within some VPN's uid range, update Netd with it.
+        // This needs to happen after the mApps update above, since removeBypassingUids() depends
+        // on mApps to check if the package can bypass VPN.
+        for (Map.Entry<String, Set<UidRange>> vpn : mVpnUidRanges.entrySet()) {
+            if (UidRange.containsUid(vpn.getValue(), uid)) {
+                final Set<Integer> changedUids = new HashSet<>();
+                changedUids.add(uid);
+                removeBypassingUids(changedUids, /* vpnAppUid */ -1);
+                updateVpnUids(vpn.getKey(), changedUids, true);
+            }
+        }
+        mAllApps.add(UserHandle.getAppId(uid));
     }
 
     /**
@@ -386,8 +416,23 @@
      * @hide
      */
     public synchronized void onPackageRemoved(int uid) {
-        Map<Integer, Boolean> apps = new HashMap<>();
+        // If the newly-removed package falls within some VPN's uid range, update Netd with it.
+        // This needs to happen before the mApps update below, since removeBypassingUids() depends
+        // on mApps to check if the package can bypass VPN.
+        for (Map.Entry<String, Set<UidRange>> vpn : mVpnUidRanges.entrySet()) {
+            if (UidRange.containsUid(vpn.getValue(), uid)) {
+                final Set<Integer> changedUids = new HashSet<>();
+                changedUids.add(uid);
+                removeBypassingUids(changedUids, /* vpnAppUid */ -1);
+                updateVpnUids(vpn.getKey(), changedUids, false);
+            }
+        }
+        // If the package has been removed from all users on the device, clear it form mAllApps.
+        if (mPackageManager.getNameForUid(uid) == null) {
+            mAllApps.remove(UserHandle.getAppId(uid));
+        }
 
+        Map<Integer, Boolean> apps = new HashMap<>();
         Boolean permission = null;
         String[] packages = mPackageManager.getPackagesForUid(uid);
         if (packages != null && packages.length > 0) {
@@ -443,6 +488,121 @@
     }
 
     /**
+     * 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 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,
+            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.
+        final Set<Integer> changedUids = intersectUids(rangesToAdd, mAllApps);
+        removeBypassingUids(changedUids, vpnAppUid);
+        updateVpnUids(iface, changedUids, true);
+        if (mVpnUidRanges.containsKey(iface)) {
+            mVpnUidRanges.get(iface).addAll(rangesToAdd);
+        } else {
+            mVpnUidRanges.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 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,
+            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);
+        updateVpnUids(iface, changedUids, false);
+        Set<UidRange> existingRanges = mVpnUidRanges.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);
+        }
+    }
+
+    /**
+     * Compute the intersection of a set of UidRanges and appIds. Returns a set of uids
+     * that satisfies:
+     *   1. falls into one of the UidRange
+     *   2. matches one of the appIds
+     */
+    private Set<Integer> intersectUids(Set<UidRange> ranges, Set<Integer> appIds) {
+        Set<Integer> result = new HashSet<>();
+        for (UidRange range : ranges) {
+            for (int userId = range.getStartUser(); userId <= range.getEndUser(); userId++) {
+                for (int appId : appIds) {
+                    final int uid = UserHandle.getUid(userId, appId);
+                    if (range.contains(uid)) {
+                        result.add(uid);
+                    }
+                }
+            }
+        }
+        return result;
+    }
+
+    /**
+     * Remove all apps which can elect to bypass the VPN from the list of uids
+     *
+     * An app can elect to bypass the VPN if it hold SYSTEM permission, or if its the active VPN
+     * app itself.
+     *
+     * @param uids The list of uids to operate on
+     * @param vpnAppUid The uid of the VPN app
+     */
+    private void removeBypassingUids(Set<Integer> uids, int vpnAppUid) {
+        uids.remove(vpnAppUid);
+        uids.removeIf(uid -> mApps.getOrDefault(uid, NETWORK) == SYSTEM);
+    }
+
+    /**
+     * Update netd about the list of uids that are under an active VPN connection which they cannot
+     * bypass.
+     *
+     * 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).
+     *
+     * @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
+     *        are to be removed from the interface.
+     */
+    private void updateVpnUids(String iface, Set<Integer> uids, boolean add) {
+        if (uids.size() == 0) {
+            return;
+        }
+        try {
+            if (add) {
+                mNetd.firewallAddUidInterfaceRules(iface, toIntArray(uids));
+            } else {
+                mNetd.firewallRemoveUidInterfaceRules(toIntArray(uids));
+            }
+        } catch (ServiceSpecificException e) {
+            // Silently ignore exception when device does not support eBPF, otherwise just log
+            // the exception and do not crash
+            if (e.errorCode != OsConstants.EOPNOTSUPP) {
+                loge("Exception when updating permissions: ", e);
+            }
+        } catch (RemoteException e) {
+            loge("Exception when updating permissions: ", e);
+        }
+    }
+
+    /**
      * Called by PackageListObserver when a package is installed/uninstalled. Send the updated
      * permission information to netd.
      *
@@ -528,6 +688,24 @@
         }
     }
 
+    /** Should only be used by unit tests */
+    @VisibleForTesting
+    public Set<UidRange> getVpnUidRanges(String iface) {
+        return mVpnUidRanges.get(iface);
+    }
+
+    /** Dump info to dumpsys */
+    public void dump(IndentingPrintWriter pw) {
+        pw.println("Interface filtering rules:");
+        pw.increaseIndent();
+        for (Map.Entry<String, Set<UidRange>> vpn : mVpnUidRanges.entrySet()) {
+            pw.println("Interface: " + vpn.getKey());
+            pw.println("UIDs: " + vpn.getValue().toString());
+            pw.println();
+        }
+        pw.decreaseIndent();
+    }
+
     private static void log(String s) {
         if (DBG) {
             Log.d(TAG, s);
diff --git a/services/core/jni/com_android_server_TestNetworkService.cpp b/services/core/jni/com_android_server_TestNetworkService.cpp
index b90ff23..36a6fde 100644
--- a/services/core/jni/com_android_server_TestNetworkService.cpp
+++ b/services/core/jni/com_android_server_TestNetworkService.cpp
@@ -54,12 +54,12 @@
     jniThrowException(env, "java/lang/IllegalStateException", msg.c_str());
 }
 
-static int createTunInterface(JNIEnv* env, const char* iface) {
+static int createTunTapInterface(JNIEnv* env, bool isTun, const char* iface) {
     base::unique_fd tun(open("/dev/tun", O_RDWR | O_NONBLOCK));
     ifreq ifr{};
 
     // Allocate interface.
-    ifr.ifr_flags = IFF_TUN | IFF_NO_PI;
+    ifr.ifr_flags = (isTun ? IFF_TUN : IFF_TAP) | IFF_NO_PI;
     strlcpy(ifr.ifr_name, iface, IFNAMSIZ);
     if (ioctl(tun.get(), TUNSETIFF, &ifr)) {
         throwException(env, errno, "allocating", ifr.ifr_name);
@@ -80,23 +80,23 @@
 
 //------------------------------------------------------------------------------
 
-static jint create(JNIEnv* env, jobject /* thiz */, jstring jIface) {
+static jint create(JNIEnv* env, jobject /* thiz */, jboolean isTun, jstring jIface) {
     ScopedUtfChars iface(env, jIface);
     if (!iface.c_str()) {
         jniThrowNullPointerException(env, "iface");
         return -1;
     }
 
-    int tun = createTunInterface(env, iface.c_str());
+    int tun = createTunTapInterface(env, isTun, iface.c_str());
 
-    // Any exceptions will be thrown from the createTunInterface call
+    // Any exceptions will be thrown from the createTunTapInterface call
     return tun;
 }
 
 //------------------------------------------------------------------------------
 
 static const JNINativeMethod gMethods[] = {
-    {"jniCreateTun", "(Ljava/lang/String;)I", (void*)create},
+    {"jniCreateTunTap", "(ZLjava/lang/String;)I", (void*)create},
 };
 
 int register_android_server_TestNetworkService(JNIEnv* env) {
diff --git a/tests/net/java/android/net/RouteInfoTest.java b/tests/net/java/android/net/RouteInfoTest.java
index 831fefd..2edbd40 100644
--- a/tests/net/java/android/net/RouteInfoTest.java
+++ b/tests/net/java/android/net/RouteInfoTest.java
@@ -16,15 +16,16 @@
 
 package android.net;
 
-import java.lang.reflect.Method;
-import java.net.InetAddress;
+import static android.net.RouteInfo.RTN_UNREACHABLE;
 
-import android.net.IpPrefix;
-import android.net.RouteInfo;
 import android.os.Parcel;
+import android.test.suitebuilder.annotation.SmallTest;
 
 import junit.framework.TestCase;
-import android.test.suitebuilder.annotation.SmallTest;
+
+import java.net.Inet4Address;
+import java.net.Inet6Address;
+import java.net.InetAddress;
 
 public class RouteInfoTest extends TestCase {
 
@@ -152,67 +153,85 @@
     }
 
     public void testHostAndDefaultRoutes() {
-      RouteInfo r;
+        RouteInfo r;
 
-      r = new RouteInfo(Prefix("0.0.0.0/0"), Address("0.0.0.0"), "wlan0");
-      assertFalse(r.isHostRoute());
-      assertTrue(r.isDefaultRoute());
-      assertTrue(r.isIPv4Default());
-      assertFalse(r.isIPv6Default());
+        r = new RouteInfo(Prefix("0.0.0.0/0"), Address("0.0.0.0"), "wlan0");
+        assertFalse(r.isHostRoute());
+        assertTrue(r.isDefaultRoute());
+        assertTrue(r.isIPv4Default());
+        assertFalse(r.isIPv6Default());
 
-      r = new RouteInfo(Prefix("::/0"), Address("::"), "wlan0");
-      assertFalse(r.isHostRoute());
-      assertTrue(r.isDefaultRoute());
-      assertFalse(r.isIPv4Default());
-      assertTrue(r.isIPv6Default());
+        r = new RouteInfo(Prefix("::/0"), Address("::"), "wlan0");
+        assertFalse(r.isHostRoute());
+        assertTrue(r.isDefaultRoute());
+        assertFalse(r.isIPv4Default());
+        assertTrue(r.isIPv6Default());
 
-      r = new RouteInfo(Prefix("192.0.2.0/24"), null, "wlan0");
-      assertFalse(r.isHostRoute());
-      assertFalse(r.isDefaultRoute());
-      assertFalse(r.isIPv4Default());
-      assertFalse(r.isIPv6Default());
+        r = new RouteInfo(Prefix("192.0.2.0/24"), null, "wlan0");
+        assertFalse(r.isHostRoute());
+        assertFalse(r.isDefaultRoute());
+        assertFalse(r.isIPv4Default());
+        assertFalse(r.isIPv6Default());
 
-      r = new RouteInfo(Prefix("2001:db8::/48"), null, "wlan0");
-      assertFalse(r.isHostRoute());
-      assertFalse(r.isDefaultRoute());
-      assertFalse(r.isIPv4Default());
-      assertFalse(r.isIPv6Default());
+        r = new RouteInfo(Prefix("2001:db8::/48"), null, "wlan0");
+        assertFalse(r.isHostRoute());
+        assertFalse(r.isDefaultRoute());
+        assertFalse(r.isIPv4Default());
+        assertFalse(r.isIPv6Default());
 
-      r = new RouteInfo(Prefix("192.0.2.0/32"), Address("0.0.0.0"), "wlan0");
-      assertTrue(r.isHostRoute());
-      assertFalse(r.isDefaultRoute());
-      assertFalse(r.isIPv4Default());
-      assertFalse(r.isIPv6Default());
+        r = new RouteInfo(Prefix("192.0.2.0/32"), Address("0.0.0.0"), "wlan0");
+        assertTrue(r.isHostRoute());
+        assertFalse(r.isDefaultRoute());
+        assertFalse(r.isIPv4Default());
+        assertFalse(r.isIPv6Default());
 
-      r = new RouteInfo(Prefix("2001:db8::/128"), Address("::"), "wlan0");
-      assertTrue(r.isHostRoute());
-      assertFalse(r.isDefaultRoute());
-      assertFalse(r.isIPv4Default());
-      assertFalse(r.isIPv6Default());
+        r = new RouteInfo(Prefix("2001:db8::/128"), Address("::"), "wlan0");
+        assertTrue(r.isHostRoute());
+        assertFalse(r.isDefaultRoute());
+        assertFalse(r.isIPv4Default());
+        assertFalse(r.isIPv6Default());
 
-      r = new RouteInfo(Prefix("192.0.2.0/32"), null, "wlan0");
-      assertTrue(r.isHostRoute());
-      assertFalse(r.isDefaultRoute());
-      assertFalse(r.isIPv4Default());
-      assertFalse(r.isIPv6Default());
+        r = new RouteInfo(Prefix("192.0.2.0/32"), null, "wlan0");
+        assertTrue(r.isHostRoute());
+        assertFalse(r.isDefaultRoute());
+        assertFalse(r.isIPv4Default());
+        assertFalse(r.isIPv6Default());
 
-      r = new RouteInfo(Prefix("2001:db8::/128"), null, "wlan0");
-      assertTrue(r.isHostRoute());
-      assertFalse(r.isDefaultRoute());
-      assertFalse(r.isIPv4Default());
-      assertFalse(r.isIPv6Default());
+        r = new RouteInfo(Prefix("2001:db8::/128"), null, "wlan0");
+        assertTrue(r.isHostRoute());
+        assertFalse(r.isDefaultRoute());
+        assertFalse(r.isIPv4Default());
+        assertFalse(r.isIPv6Default());
 
-      r = new RouteInfo(Prefix("::/128"), Address("fe80::"), "wlan0");
-      assertTrue(r.isHostRoute());
-      assertFalse(r.isDefaultRoute());
-      assertFalse(r.isIPv4Default());
-      assertFalse(r.isIPv6Default());
+        r = new RouteInfo(Prefix("::/128"), Address("fe80::"), "wlan0");
+        assertTrue(r.isHostRoute());
+        assertFalse(r.isDefaultRoute());
+        assertFalse(r.isIPv4Default());
+        assertFalse(r.isIPv6Default());
 
-      r = new RouteInfo(Prefix("0.0.0.0/32"), Address("192.0.2.1"), "wlan0");
-      assertTrue(r.isHostRoute());
-      assertFalse(r.isDefaultRoute());
-      assertFalse(r.isIPv4Default());
-      assertFalse(r.isIPv6Default());
+        r = new RouteInfo(Prefix("0.0.0.0/32"), Address("192.0.2.1"), "wlan0");
+        assertTrue(r.isHostRoute());
+        assertFalse(r.isDefaultRoute());
+        assertFalse(r.isIPv4Default());
+        assertFalse(r.isIPv6Default());
+
+        r = new RouteInfo(Prefix("0.0.0.0/32"), Address("192.0.2.1"), "wlan0");
+        assertTrue(r.isHostRoute());
+        assertFalse(r.isDefaultRoute());
+        assertFalse(r.isIPv4Default());
+        assertFalse(r.isIPv6Default());
+
+        r = new RouteInfo(new IpPrefix(Inet4Address.ANY, 0), RTN_UNREACHABLE);
+        assertFalse(r.isHostRoute());
+        assertFalse(r.isDefaultRoute());
+        assertFalse(r.isIPv4Default());
+        assertFalse(r.isIPv6Default());
+
+        r = new RouteInfo(new IpPrefix(Inet6Address.ANY, 0), RTN_UNREACHABLE);
+        assertFalse(r.isHostRoute());
+        assertFalse(r.isDefaultRoute());
+        assertFalse(r.isIPv4Default());
+        assertFalse(r.isIPv6Default());
     }
 
     public void testTruncation() {
diff --git a/tests/net/java/com/android/server/ConnectivityServiceTest.java b/tests/net/java/com/android/server/ConnectivityServiceTest.java
index c2fc0b3..ee9d785 100644
--- a/tests/net/java/com/android/server/ConnectivityServiceTest.java
+++ b/tests/net/java/com/android/server/ConnectivityServiceTest.java
@@ -16,6 +16,8 @@
 
 package com.android.server;
 
+import static android.content.pm.PackageManager.GET_PERMISSIONS;
+import static android.content.pm.PackageManager.MATCH_ANY_USER;
 import static android.net.ConnectivityManager.CONNECTIVITY_ACTION;
 import static android.net.ConnectivityManager.NETID_UNSET;
 import static android.net.ConnectivityManager.PRIVATE_DNS_MODE_OFF;
@@ -60,11 +62,13 @@
 import static android.net.NetworkPolicyManager.RULE_NONE;
 import static android.net.NetworkPolicyManager.RULE_REJECT_ALL;
 import static android.net.NetworkPolicyManager.RULE_REJECT_METERED;
+import static android.net.RouteInfo.RTN_UNREACHABLE;
 
 import static com.android.internal.util.TestUtils.waitForIdleHandler;
 import static com.android.internal.util.TestUtils.waitForIdleLooper;
 import static com.android.internal.util.TestUtils.waitForIdleSerialExecutor;
 
+import static org.junit.Assert.assertArrayEquals;
 import static org.junit.Assert.assertEquals;
 import static org.junit.Assert.assertFalse;
 import static org.junit.Assert.assertNotEquals;
@@ -72,12 +76,14 @@
 import static org.junit.Assert.assertNull;
 import static org.junit.Assert.assertTrue;
 import static org.junit.Assert.fail;
+import static org.mockito.ArgumentMatchers.eq;
 import static org.mockito.Matchers.anyInt;
 import static org.mockito.Mockito.any;
 import static org.mockito.Mockito.atLeastOnce;
 import static org.mockito.Mockito.doAnswer;
 import static org.mockito.Mockito.doNothing;
 import static org.mockito.Mockito.eq;
+import static org.mockito.Mockito.inOrder;
 import static org.mockito.Mockito.mock;
 import static org.mockito.Mockito.never;
 import static org.mockito.Mockito.reset;
@@ -97,6 +103,10 @@
 import android.content.Context;
 import android.content.Intent;
 import android.content.IntentFilter;
+import android.content.pm.ApplicationInfo;
+import android.content.pm.PackageInfo;
+import android.content.pm.PackageManager;
+import android.content.pm.UserInfo;
 import android.content.res.Resources;
 import android.net.ConnectivityManager;
 import android.net.ConnectivityManager.NetworkCallback;
@@ -151,6 +161,7 @@
 import android.os.RemoteException;
 import android.os.SystemClock;
 import android.os.UserHandle;
+import android.os.UserManager;
 import android.provider.Settings;
 import android.system.Os;
 import android.test.mock.MockContentResolver;
@@ -186,6 +197,7 @@
 import org.junit.Test;
 import org.junit.runner.RunWith;
 import org.mockito.ArgumentCaptor;
+import org.mockito.InOrder;
 import org.mockito.Mock;
 import org.mockito.MockitoAnnotations;
 import org.mockito.Spy;
@@ -194,6 +206,7 @@
 import java.io.IOException;
 import java.net.DatagramSocket;
 import java.net.Inet4Address;
+import java.net.Inet6Address;
 import java.net.InetAddress;
 import java.net.InetSocketAddress;
 import java.net.Socket;
@@ -261,6 +274,8 @@
     @Mock IDnsResolver mMockDnsResolver;
     @Mock INetd mMockNetd;
     @Mock NetworkStackClient mNetworkStack;
+    @Mock PackageManager mPackageManager;
+    @Mock UserManager mUserManager;
 
     private ArgumentCaptor<String[]> mStringArrayCaptor = ArgumentCaptor.forClass(String[].class);
 
@@ -331,6 +346,7 @@
             if (Context.CONNECTIVITY_SERVICE.equals(name)) return mCm;
             if (Context.NOTIFICATION_SERVICE.equals(name)) return mock(NotificationManager.class);
             if (Context.NETWORK_STACK_SERVICE.equals(name)) return mNetworkStack;
+            if (Context.USER_SERVICE.equals(name)) return mUserManager;
             return super.getSystemService(name);
         }
 
@@ -343,6 +359,11 @@
         public Resources getResources() {
             return mResources;
         }
+
+        @Override
+        public PackageManager getPackageManager() {
+            return mPackageManager;
+        }
     }
 
     public void waitForIdle(int timeoutMsAsInt) {
@@ -1057,7 +1078,7 @@
         public WrappedConnectivityService(Context context, INetworkManagementService netManager,
                 INetworkStatsService statsService, INetworkPolicyManager policyManager,
                 IpConnectivityLog log, INetd netd, IDnsResolver dnsResolver) {
-            super(context, netManager, statsService, policyManager, dnsResolver, log);
+            super(context, netManager, statsService, policyManager, dnsResolver, log, netd);
             mNetd = netd;
             mLingerDelayMs = TEST_LINGER_DELAY_MS;
         }
@@ -1196,6 +1217,11 @@
         fail("ConditionVariable was blocked for more than " + TIMEOUT_MS + "ms");
     }
 
+    private static final int VPN_USER = 0;
+    private static final int APP1_UID = UserHandle.getUid(VPN_USER, 10100);
+    private static final int APP2_UID = UserHandle.getUid(VPN_USER, 10101);
+    private static final int VPN_UID = UserHandle.getUid(VPN_USER, 10043);
+
     @Before
     public void setUp() throws Exception {
         mContext = InstrumentationRegistry.getContext();
@@ -1203,6 +1229,17 @@
         MockitoAnnotations.initMocks(this);
         when(mMetricsService.defaultNetworkMetrics()).thenReturn(mDefaultNetworkMetrics);
 
+        when(mUserManager.getUsers(eq(true))).thenReturn(
+                Arrays.asList(new UserInfo[] {
+                        new UserInfo(VPN_USER, "", 0),
+                }));
+        when(mPackageManager.getInstalledPackages(eq(GET_PERMISSIONS | MATCH_ANY_USER))).thenReturn(
+                Arrays.asList(new PackageInfo[] {
+                        buildPackageInfo(/* SYSTEM */ false, APP1_UID),
+                        buildPackageInfo(/* SYSTEM */ false, APP2_UID),
+                        buildPackageInfo(/* SYSTEM */ false, VPN_UID)
+                }));
+
         // InstrumentationTestRunner prepares a looper, but AndroidJUnitRunner does not.
         // http://b/25897652 .
         if (Looper.myLooper() == null) {
@@ -6129,4 +6166,165 @@
         assertEquals(testProxyInfo, mService.getProxyForNetwork(mWiFiNetworkAgent.getNetwork()));
         assertEquals(testProxyInfo, mService.getProxyForNetwork(null));
     }
+
+    @Test
+    public void testFullyRoutedVpnResultsInInterfaceFilteringRules() throws Exception {
+        LinkProperties lp = new LinkProperties();
+        lp.setInterfaceName("tun0");
+        lp.addRoute(new RouteInfo(new IpPrefix(Inet4Address.ANY, 0), null));
+        // The uid range needs to cover the test app so the network is visible to it.
+        final Set<UidRange> vpnRange = Collections.singleton(UidRange.createForUser(VPN_USER));
+        final MockNetworkAgent vpnNetworkAgent = establishVpn(lp, VPN_UID, vpnRange);
+
+        // Connected VPN should have interface rules set up. There are two expected invocations,
+        // one during VPN uid update, one during VPN LinkProperties update
+        ArgumentCaptor<int[]> uidCaptor = ArgumentCaptor.forClass(int[].class);
+        verify(mMockNetd, times(2)).firewallAddUidInterfaceRules(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));
+
+        vpnNetworkAgent.disconnect();
+        waitForIdle();
+
+        // Disconnected VPN should have interface rules removed
+        verify(mMockNetd).firewallRemoveUidInterfaceRules(uidCaptor.capture());
+        assertContainsExactly(uidCaptor.getValue(), APP1_UID, APP2_UID);
+        assertNull(mService.mPermissionMonitor.getVpnUidRanges("tun0"));
+    }
+
+    @Test
+    public void testLegacyVpnDoesNotResultInInterfaceFilteringRule() throws Exception {
+        LinkProperties lp = new LinkProperties();
+        lp.setInterfaceName("tun0");
+        lp.addRoute(new RouteInfo(new IpPrefix(Inet4Address.ANY, 0), null));
+        // The uid range needs to cover the test app so the network is visible to it.
+        final Set<UidRange> vpnRange = Collections.singleton(UidRange.createForUser(VPN_USER));
+        final MockNetworkAgent vpnNetworkAgent = establishVpn(lp, Process.SYSTEM_UID, vpnRange);
+
+        // Legacy VPN should not have interface rules set up
+        verify(mMockNetd, never()).firewallAddUidInterfaceRules(any(), any());
+    }
+
+    public void testLocalIpv4OnlyVpnDoesNotResultInInterfaceFilteringRule()
+            throws Exception {
+        LinkProperties lp = new LinkProperties();
+        lp.setInterfaceName("tun0");
+        lp.addRoute(new RouteInfo(new IpPrefix("192.0.2.0/24"), null, "tun0"));
+        lp.addRoute(new RouteInfo(new IpPrefix(Inet6Address.ANY, 0), RTN_UNREACHABLE));
+        // The uid range needs to cover the test app so the network is visible to it.
+        final Set<UidRange> vpnRange = Collections.singleton(UidRange.createForUser(VPN_USER));
+        final MockNetworkAgent vpnNetworkAgent = establishVpn(lp, Process.SYSTEM_UID, vpnRange);
+
+        // IPv6 unreachable route should not be misinterpreted as a default route
+        verify(mMockNetd, never()).firewallAddUidInterfaceRules(any(), any());
+    }
+
+    @Test
+    public void testVpnHandoverChangesInterfaceFilteringRule() throws Exception {
+        LinkProperties lp = new LinkProperties();
+        lp.setInterfaceName("tun0");
+        lp.addRoute(new RouteInfo(new IpPrefix(Inet4Address.ANY, 0), null));
+        // The uid range needs to cover the test app so the network is visible to it.
+        final Set<UidRange> vpnRange = Collections.singleton(UidRange.createForUser(VPN_USER));
+        final MockNetworkAgent vpnNetworkAgent = establishVpn(lp, VPN_UID, vpnRange);
+
+        // Connected VPN should have interface rules set up. There are two expected invocations,
+        // one during VPN uid update, one during VPN LinkProperties update
+        ArgumentCaptor<int[]> uidCaptor = ArgumentCaptor.forClass(int[].class);
+        verify(mMockNetd, times(2)).firewallAddUidInterfaceRules(eq("tun0"), uidCaptor.capture());
+        assertContainsExactly(uidCaptor.getAllValues().get(0), APP1_UID, APP2_UID);
+        assertContainsExactly(uidCaptor.getAllValues().get(1), APP1_UID, APP2_UID);
+
+        reset(mMockNetd);
+        InOrder inOrder = inOrder(mMockNetd);
+        lp.setInterfaceName("tun1");
+        vpnNetworkAgent.sendLinkProperties(lp);
+        waitForIdle();
+        // VPN handover (switch to a new interface) should result in rules being updated (old rules
+        // removed first, then new rules added)
+        inOrder.verify(mMockNetd).firewallRemoveUidInterfaceRules(uidCaptor.capture());
+        assertContainsExactly(uidCaptor.getValue(), APP1_UID, APP2_UID);
+        inOrder.verify(mMockNetd).firewallAddUidInterfaceRules(eq("tun1"), uidCaptor.capture());
+        assertContainsExactly(uidCaptor.getValue(), APP1_UID, APP2_UID);
+
+        reset(mMockNetd);
+        lp = new LinkProperties();
+        lp.setInterfaceName("tun1");
+        lp.addRoute(new RouteInfo(new IpPrefix("192.0.2.0/24"), null, "tun1"));
+        vpnNetworkAgent.sendLinkProperties(lp);
+        waitForIdle();
+        // VPN not routing everything should no longer have interface filtering rules
+        verify(mMockNetd).firewallRemoveUidInterfaceRules(uidCaptor.capture());
+        assertContainsExactly(uidCaptor.getValue(), APP1_UID, APP2_UID);
+
+        reset(mMockNetd);
+        lp = new LinkProperties();
+        lp.setInterfaceName("tun1");
+        lp.addRoute(new RouteInfo(new IpPrefix(Inet6Address.ANY, 0), null));
+        vpnNetworkAgent.sendLinkProperties(lp);
+        waitForIdle();
+        // Back to routing all IPv6 traffic should have filtering rules
+        verify(mMockNetd).firewallAddUidInterfaceRules(eq("tun1"), uidCaptor.capture());
+        assertContainsExactly(uidCaptor.getValue(), APP1_UID, APP2_UID);
+    }
+
+    @Test
+    public void testUidUpdateChangesInterfaceFilteringRule() throws Exception {
+        LinkProperties lp = new LinkProperties();
+        lp.setInterfaceName("tun0");
+        lp.addRoute(new RouteInfo(new IpPrefix(Inet6Address.ANY, 0), null));
+        // The uid range needs to cover the test app so the network is visible to it.
+        final UidRange vpnRange = UidRange.createForUser(VPN_USER);
+        final MockNetworkAgent vpnNetworkAgent = establishVpn(lp, VPN_UID,
+                Collections.singleton(vpnRange));
+
+        reset(mMockNetd);
+        InOrder inOrder = inOrder(mMockNetd);
+
+        // Update to new range which is old range minus APP1, i.e. only APP2
+        final Set<UidRange> newRanges = new HashSet<>(Arrays.asList(
+                new UidRange(vpnRange.start, APP1_UID - 1),
+                new UidRange(APP1_UID + 1, vpnRange.stop)));
+        vpnNetworkAgent.setUids(newRanges);
+        waitForIdle();
+
+        ArgumentCaptor<int[]> uidCaptor = ArgumentCaptor.forClass(int[].class);
+        // Verify old rules are removed before new rules are added
+        inOrder.verify(mMockNetd).firewallRemoveUidInterfaceRules(uidCaptor.capture());
+        assertContainsExactly(uidCaptor.getValue(), APP1_UID, APP2_UID);
+        inOrder.verify(mMockNetd).firewallAddUidInterfaceRules(eq("tun0"), uidCaptor.capture());
+        assertContainsExactly(uidCaptor.getValue(), APP2_UID);
+    }
+
+
+    private MockNetworkAgent establishVpn(LinkProperties lp, int establishingUid,
+            Set<UidRange> vpnRange) {
+        final MockNetworkAgent vpnNetworkAgent = new MockNetworkAgent(TRANSPORT_VPN, lp);
+        vpnNetworkAgent.getNetworkCapabilities().setEstablishingVpnAppUid(establishingUid);
+        mMockVpn.setNetworkAgent(vpnNetworkAgent);
+        mMockVpn.connect();
+        mMockVpn.setUids(vpnRange);
+        vpnNetworkAgent.connect(true);
+        waitForIdle();
+        return vpnNetworkAgent;
+    }
+
+    private void assertContainsExactly(int[] actual, int... expected) {
+        int[] sortedActual = Arrays.copyOf(actual, actual.length);
+        int[] sortedExpected = Arrays.copyOf(expected, expected.length);
+        Arrays.sort(sortedActual);
+        Arrays.sort(sortedExpected);
+        assertArrayEquals(sortedExpected, sortedActual);
+    }
+
+    private static PackageInfo buildPackageInfo(boolean hasSystemPermission, int uid) {
+        final PackageInfo packageInfo = new PackageInfo();
+        packageInfo.requestedPermissions = new String[0];
+        packageInfo.applicationInfo = new ApplicationInfo();
+        packageInfo.applicationInfo.privateFlags = 0;
+        packageInfo.applicationInfo.uid = UserHandle.getUid(UserHandle.USER_SYSTEM,
+                UserHandle.getAppId(uid));
+        return packageInfo;
+    }
 }
diff --git a/tests/net/java/com/android/server/connectivity/PermissionMonitorTest.java b/tests/net/java/com/android/server/connectivity/PermissionMonitorTest.java
index 106cd1f..62a4718 100644
--- a/tests/net/java/com/android/server/connectivity/PermissionMonitorTest.java
+++ b/tests/net/java/com/android/server/connectivity/PermissionMonitorTest.java
@@ -28,6 +28,7 @@
 import static android.content.pm.ApplicationInfo.PRIVATE_FLAG_VENDOR;
 import static android.content.pm.PackageInfo.REQUESTED_PERMISSION_GRANTED;
 import static android.content.pm.PackageManager.GET_PERMISSIONS;
+import static android.content.pm.PackageManager.MATCH_ANY_USER;
 import static android.os.Process.SYSTEM_UID;
 
 import static com.android.server.connectivity.PermissionMonitor.NETWORK;
@@ -36,13 +37,16 @@
 import static junit.framework.Assert.fail;
 
 import static org.junit.Assert.assertFalse;
+import static org.junit.Assert.assertNull;
 import static org.junit.Assert.assertTrue;
+import static org.mockito.AdditionalMatchers.aryEq;
 import static org.mockito.ArgumentMatchers.any;
-import static org.mockito.Matchers.anyString;
-import static org.mockito.Mockito.anyInt;
+import static org.mockito.ArgumentMatchers.anyInt;
+import static org.mockito.ArgumentMatchers.anyString;
+import static org.mockito.ArgumentMatchers.eq;
 import static org.mockito.Mockito.doAnswer;
 import static org.mockito.Mockito.doReturn;
-import static org.mockito.Mockito.eq;
+import static org.mockito.Mockito.reset;
 import static org.mockito.Mockito.spy;
 import static org.mockito.Mockito.verify;
 import static org.mockito.Mockito.when;
@@ -53,10 +57,12 @@
 import android.content.pm.PackageList;
 import android.content.pm.PackageManager;
 import android.content.pm.PackageManagerInternal;
+import android.content.pm.UserInfo;
 import android.net.INetd;
+import android.net.UidRange;
 import android.os.Build;
-import android.os.INetworkManagementService;
 import android.os.UserHandle;
+import android.os.UserManager;
 import android.util.SparseIntArray;
 
 import androidx.test.filters.SmallTest;
@@ -73,7 +79,12 @@
 import org.mockito.invocation.InvocationOnMock;
 
 import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.Collections;
 import java.util.HashMap;
+import java.util.HashSet;
+import java.util.Set;
+
 
 @RunWith(AndroidJUnit4.class)
 @SmallTest
@@ -84,10 +95,12 @@
     private static final int MOCK_UID2 = 10086;
     private static final int SYSTEM_UID1 = 1000;
     private static final int SYSTEM_UID2 = 1008;
+    private static final int VPN_UID = 10002;
     private static final String MOCK_PACKAGE1 = "appName1";
     private static final String MOCK_PACKAGE2 = "appName2";
     private static final String SYSTEM_PACKAGE1 = "sysName1";
     private static final String SYSTEM_PACKAGE2 = "sysName2";
+    private static final String VPN_PACKAGE = "vpnApp";
     private static final String PARTITION_SYSTEM = "system";
     private static final String PARTITION_OEM = "oem";
     private static final String PARTITION_PRODUCT = "product";
@@ -97,9 +110,9 @@
 
     @Mock private Context mContext;
     @Mock private PackageManager mPackageManager;
-    @Mock private INetworkManagementService mNMS;
     @Mock private INetd mNetdService;
     @Mock private PackageManagerInternal mMockPmi;
+    @Mock private UserManager mUserManager;
 
     private PackageManagerInternal.PackageListObserver mObserver;
     private PermissionMonitor mPermissionMonitor;
@@ -108,7 +121,14 @@
     public void setUp() throws Exception {
         MockitoAnnotations.initMocks(this);
         when(mContext.getPackageManager()).thenReturn(mPackageManager);
-        mPermissionMonitor = spy(new PermissionMonitor(mContext, mNMS, mNetdService));
+        when(mContext.getSystemService(eq(Context.USER_SERVICE))).thenReturn(mUserManager);
+        when(mUserManager.getUsers(eq(true))).thenReturn(
+                Arrays.asList(new UserInfo[] {
+                        new UserInfo(MOCK_USER1, "", 0),
+                        new UserInfo(MOCK_USER2, "", 0),
+                }));
+
+        mPermissionMonitor = spy(new PermissionMonitor(mContext, mNetdService));
 
         LocalServices.removeServiceForTest(PackageManagerInternal.class);
         LocalServices.addService(PackageManagerInternal.class, mMockPmi);
@@ -134,7 +154,7 @@
         return mPermissionMonitor.hasUseBackgroundNetworksPermission(uid);
     }
 
-    private PackageInfo packageInfoWithPermissions(String[] permissions, String partition) {
+    private static PackageInfo packageInfoWithPermissions(String[] permissions, String partition) {
         int[] requestedPermissionsFlags = new int[permissions.length];
         for (int i = 0; i < permissions.length; i++) {
             requestedPermissionsFlags[i] = REQUESTED_PERMISSION_GRANTED;
@@ -143,7 +163,7 @@
                 requestedPermissionsFlags);
     }
 
-    private PackageInfo packageInfoWithPermissions(String[] permissions, String partition,
+    private static PackageInfo packageInfoWithPermissions(String[] permissions, String partition,
             int[] requestedPermissionsFlags) {
         final PackageInfo packageInfo = new PackageInfo();
         packageInfo.requestedPermissions = permissions;
@@ -165,6 +185,18 @@
         return packageInfo;
     }
 
+    private static PackageInfo buildPackageInfo(boolean hasSystemPermission, int uid, int userId) {
+        final PackageInfo pkgInfo;
+        if (hasSystemPermission) {
+            pkgInfo = packageInfoWithPermissions(new String[] {CHANGE_NETWORK_STATE, NETWORK_STACK},
+                    PARTITION_SYSTEM);
+        } else {
+            pkgInfo = packageInfoWithPermissions(new String[] {}, "");
+        }
+        pkgInfo.applicationInfo.uid = UserHandle.getUid(userId, UserHandle.getAppId(uid));
+        return pkgInfo;
+    }
+
     @Test
     public void testHasPermission() {
         PackageInfo app = packageInfoWithPermissions(new String[] {}, PARTITION_SYSTEM);
@@ -245,14 +277,14 @@
         assertFalse(hasBgPermission(PARTITION_VENDOR, VERSION_Q, MOCK_UID1, CHANGE_WIFI_STATE));
     }
 
-    private class NMSMonitor {
+    private class NetdMonitor {
         private final HashMap<Integer, Boolean> mApps = new HashMap<>();
 
-        NMSMonitor(INetworkManagementService mockNMS) throws Exception {
+        NetdMonitor(INetd mockNetd) throws Exception {
             // Add hook to verify and track result of setPermission.
             doAnswer((InvocationOnMock invocation) -> {
                 final Object[] args = invocation.getArguments();
-                final Boolean isSystem = args[0].equals("SYSTEM");
+                final Boolean isSystem = args[0].equals(INetd.PERMISSION_SYSTEM);
                 for (final int uid : (int[]) args[1]) {
                     // TODO: Currently, permission monitor will send duplicate commands for each uid
                     // corresponding to each user. Need to fix that and uncomment below test.
@@ -262,7 +294,7 @@
                     mApps.put(uid, isSystem);
                 }
                 return null;
-            }).when(mockNMS).setPermission(anyString(), any(int[].class));
+            }).when(mockNetd).networkSetPermissionForUser(anyInt(), any(int[].class));
 
             // Add hook to verify and track result of clearPermission.
             doAnswer((InvocationOnMock invocation) -> {
@@ -276,7 +308,7 @@
                     mApps.remove(uid);
                 }
                 return null;
-            }).when(mockNMS).clearPermission(any(int[].class));
+            }).when(mockNetd).networkClearPermissionForUser(any(int[].class));
         }
 
         public void expectPermission(Boolean permission, int[] users, int[] apps) {
@@ -307,7 +339,7 @@
 
     @Test
     public void testUserAndPackageAddRemove() throws Exception {
-        final NMSMonitor mNMSMonitor = new NMSMonitor(mNMS);
+        final NetdMonitor mNetdMonitor = new NetdMonitor(mNetdService);
 
         // MOCK_UID1: MOCK_PACKAGE1 only has network permission.
         // SYSTEM_UID: SYSTEM_PACKAGE1 has system permission.
@@ -323,48 +355,123 @@
         // Add SYSTEM_PACKAGE2, expect only have network permission.
         mPermissionMonitor.onUserAdded(MOCK_USER1);
         addPackageForUsers(new int[]{MOCK_USER1}, SYSTEM_PACKAGE2, SYSTEM_UID);
-        mNMSMonitor.expectPermission(NETWORK, new int[]{MOCK_USER1}, new int[]{SYSTEM_UID});
+        mNetdMonitor.expectPermission(NETWORK, new int[]{MOCK_USER1}, new int[]{SYSTEM_UID});
 
         // Add SYSTEM_PACKAGE1, expect permission escalate.
         addPackageForUsers(new int[]{MOCK_USER1}, SYSTEM_PACKAGE1, SYSTEM_UID);
-        mNMSMonitor.expectPermission(SYSTEM, new int[]{MOCK_USER1}, new int[]{SYSTEM_UID});
+        mNetdMonitor.expectPermission(SYSTEM, new int[]{MOCK_USER1}, new int[]{SYSTEM_UID});
 
         mPermissionMonitor.onUserAdded(MOCK_USER2);
-        mNMSMonitor.expectPermission(SYSTEM, new int[]{MOCK_USER1, MOCK_USER2},
+        mNetdMonitor.expectPermission(SYSTEM, new int[]{MOCK_USER1, MOCK_USER2},
                 new int[]{SYSTEM_UID});
 
         addPackageForUsers(new int[]{MOCK_USER1, MOCK_USER2}, MOCK_PACKAGE1, MOCK_UID1);
-        mNMSMonitor.expectPermission(SYSTEM, new int[]{MOCK_USER1, MOCK_USER2},
+        mNetdMonitor.expectPermission(SYSTEM, new int[]{MOCK_USER1, MOCK_USER2},
                 new int[]{SYSTEM_UID});
-        mNMSMonitor.expectPermission(NETWORK, new int[]{MOCK_USER1, MOCK_USER2},
+        mNetdMonitor.expectPermission(NETWORK, new int[]{MOCK_USER1, MOCK_USER2},
                 new int[]{MOCK_UID1});
 
         // Remove MOCK_UID1, expect no permission left for all user.
         mPermissionMonitor.onPackageRemoved(MOCK_UID1);
         removePackageForUsers(new int[]{MOCK_USER1, MOCK_USER2}, MOCK_UID1);
-        mNMSMonitor.expectNoPermission(new int[]{MOCK_USER1, MOCK_USER2}, new int[]{MOCK_UID1});
+        mNetdMonitor.expectNoPermission(new int[]{MOCK_USER1, MOCK_USER2}, new int[]{MOCK_UID1});
 
         // Remove SYSTEM_PACKAGE1, expect permission downgrade.
         when(mPackageManager.getPackagesForUid(anyInt())).thenReturn(new String[]{SYSTEM_PACKAGE2});
         removePackageForUsers(new int[]{MOCK_USER1, MOCK_USER2}, SYSTEM_UID);
-        mNMSMonitor.expectPermission(NETWORK, new int[]{MOCK_USER1, MOCK_USER2},
+        mNetdMonitor.expectPermission(NETWORK, new int[]{MOCK_USER1, MOCK_USER2},
                 new int[]{SYSTEM_UID});
 
         mPermissionMonitor.onUserRemoved(MOCK_USER1);
-        mNMSMonitor.expectPermission(NETWORK, new int[]{MOCK_USER2}, new int[]{SYSTEM_UID});
+        mNetdMonitor.expectPermission(NETWORK, new int[]{MOCK_USER2}, new int[]{SYSTEM_UID});
 
         // Remove all packages, expect no permission left.
         when(mPackageManager.getPackagesForUid(anyInt())).thenReturn(new String[]{});
         removePackageForUsers(new int[]{MOCK_USER2}, SYSTEM_UID);
-        mNMSMonitor.expectNoPermission(new int[]{MOCK_USER1, MOCK_USER2},
+        mNetdMonitor.expectNoPermission(new int[]{MOCK_USER1, MOCK_USER2},
                 new int[]{SYSTEM_UID, MOCK_UID1});
 
         // Remove last user, expect no redundant clearPermission is invoked.
         mPermissionMonitor.onUserRemoved(MOCK_USER2);
-        mNMSMonitor.expectNoPermission(new int[]{MOCK_USER1, MOCK_USER2},
+        mNetdMonitor.expectNoPermission(new int[]{MOCK_USER1, MOCK_USER2},
                 new int[]{SYSTEM_UID, MOCK_UID1});
     }
 
+    @Test
+    public void testUidFilteringDuringVpnConnectDisconnectAndUidUpdates() throws Exception {
+        when(mPackageManager.getInstalledPackages(eq(GET_PERMISSIONS | MATCH_ANY_USER))).thenReturn(
+                Arrays.asList(new PackageInfo[] {
+                        buildPackageInfo(/* SYSTEM */ true, SYSTEM_UID1, MOCK_USER1),
+                        buildPackageInfo(/* SYSTEM */ false, MOCK_UID1, MOCK_USER1),
+                        buildPackageInfo(/* SYSTEM */ false, MOCK_UID2, MOCK_USER1),
+                        buildPackageInfo(/* SYSTEM */ false, VPN_UID, MOCK_USER1)
+                }));
+        when(mPackageManager.getPackageInfo(eq(MOCK_PACKAGE1), eq(GET_PERMISSIONS))).thenReturn(
+                buildPackageInfo(false, MOCK_UID1, MOCK_USER1));
+        mPermissionMonitor.startMonitoring();
+        // Every app on user 0 except MOCK_UID2 are under VPN.
+        final Set<UidRange> vpnRange1 = new HashSet<>(Arrays.asList(new UidRange[] {
+                new UidRange(0, MOCK_UID2 - 1),
+                new UidRange(MOCK_UID2 + 1, UserHandle.PER_USER_RANGE - 1)}));
+        final Set<UidRange> vpnRange2 = Collections.singleton(new UidRange(MOCK_UID2, MOCK_UID2));
+
+        // When VPN is connected, expect a rule to be set up for user app MOCK_UID1
+        mPermissionMonitor.onVpnUidRangesAdded("tun0", vpnRange1, VPN_UID);
+        verify(mNetdService).firewallAddUidInterfaceRules(eq("tun0"),
+                aryEq(new int[] {MOCK_UID1}));
+
+        reset(mNetdService);
+
+        // When MOCK_UID1 package is uninstalled and reinstalled, expect Netd to be updated
+        mPermissionMonitor.onPackageRemoved(UserHandle.getUid(MOCK_USER1, MOCK_UID1));
+        verify(mNetdService).firewallRemoveUidInterfaceRules(aryEq(new int[] {MOCK_UID1}));
+        mPermissionMonitor.onPackageAdded(MOCK_PACKAGE1, UserHandle.getUid(MOCK_USER1, MOCK_UID1));
+        verify(mNetdService).firewallAddUidInterfaceRules(eq("tun0"),
+                aryEq(new int[] {MOCK_UID1}));
+
+        reset(mNetdService);
+
+        // 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);
+        verify(mNetdService).firewallRemoveUidInterfaceRules(aryEq(new int[] {MOCK_UID1}));
+        mPermissionMonitor.onVpnUidRangesAdded("tun0", vpnRange2, VPN_UID);
+        verify(mNetdService).firewallAddUidInterfaceRules(eq("tun0"),
+                aryEq(new int[] {MOCK_UID2}));
+
+        reset(mNetdService);
+
+        // When VPN is disconnected, expect rules to be torn down
+        mPermissionMonitor.onVpnUidRangesRemoved("tun0", vpnRange2, VPN_UID);
+        verify(mNetdService).firewallRemoveUidInterfaceRules(aryEq(new int[] {MOCK_UID2}));
+        assertNull(mPermissionMonitor.getVpnUidRanges("tun0"));
+    }
+
+    @Test
+    public void testUidFilteringDuringPackageInstallAndUninstall() throws Exception {
+        when(mPackageManager.getInstalledPackages(eq(GET_PERMISSIONS | MATCH_ANY_USER))).thenReturn(
+                Arrays.asList(new PackageInfo[] {
+                        buildPackageInfo(true, SYSTEM_UID1, MOCK_USER1),
+                        buildPackageInfo(false, VPN_UID, MOCK_USER1)
+                }));
+        when(mPackageManager.getPackageInfo(eq(MOCK_PACKAGE1), eq(GET_PERMISSIONS))).thenReturn(
+                        buildPackageInfo(false, MOCK_UID1, MOCK_USER1));
+
+        mPermissionMonitor.startMonitoring();
+        final Set<UidRange> vpnRange = Collections.singleton(UidRange.createForUser(MOCK_USER1));
+        mPermissionMonitor.onVpnUidRangesAdded("tun0", vpnRange, VPN_UID);
+
+        // Newly-installed package should have uid rules added
+        mPermissionMonitor.onPackageAdded(MOCK_PACKAGE1, UserHandle.getUid(MOCK_USER1, MOCK_UID1));
+        verify(mNetdService).firewallAddUidInterfaceRules(eq("tun0"),
+                aryEq(new int[] {MOCK_UID1}));
+
+        // Removed package should have its uid rules removed
+        mPermissionMonitor.onPackageRemoved(UserHandle.getUid(MOCK_USER1, MOCK_UID1));
+        verify(mNetdService).firewallRemoveUidInterfaceRules(aryEq(new int[] {MOCK_UID1}));
+    }
+
+
     // 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
     // called multiple times with the uid corresponding to each user.