diff --git a/framework/src/android/net/ConnectivityFrameworkInitializer.java b/framework/src/android/net/ConnectivityFrameworkInitializer.java
new file mode 100644
index 0000000..9afa5d1
--- /dev/null
+++ b/framework/src/android/net/ConnectivityFrameworkInitializer.java
@@ -0,0 +1,83 @@
+/*
+ * Copyright (C) 2021 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package android.net;
+
+import android.annotation.SystemApi;
+import android.app.SystemServiceRegistry;
+import android.content.Context;
+
+/**
+ * Class for performing registration for all core connectivity services.
+ *
+ * @hide
+ */
+@SystemApi(client = SystemApi.Client.MODULE_LIBRARIES)
+public final class ConnectivityFrameworkInitializer {
+    private ConnectivityFrameworkInitializer() {}
+
+    /**
+     * Called by {@link SystemServiceRegistry}'s static initializer and registers all core
+     * connectivity services to {@link Context}, so that {@link Context#getSystemService} can
+     * return them.
+     *
+     * @throws IllegalStateException if this is called anywhere besides
+     * {@link SystemServiceRegistry}.
+     */
+    public static void registerServiceWrappers() {
+        // registerContextAwareService will throw if this is called outside of SystemServiceRegistry
+        // initialization.
+        SystemServiceRegistry.registerContextAwareService(
+                Context.CONNECTIVITY_SERVICE,
+                ConnectivityManager.class,
+                (context, serviceBinder) -> {
+                    IConnectivityManager icm = IConnectivityManager.Stub.asInterface(serviceBinder);
+                    return new ConnectivityManager(context, icm);
+                }
+        );
+
+        // TODO: move outside of the connectivity JAR
+        SystemServiceRegistry.registerContextAwareService(
+                Context.VPN_MANAGEMENT_SERVICE,
+                VpnManager.class,
+                (context) -> {
+                    final ConnectivityManager cm = context.getSystemService(
+                            ConnectivityManager.class);
+                    return cm.createVpnManager();
+                }
+        );
+
+        SystemServiceRegistry.registerContextAwareService(
+                Context.CONNECTIVITY_DIAGNOSTICS_SERVICE,
+                ConnectivityDiagnosticsManager.class,
+                (context) -> {
+                    final ConnectivityManager cm = context.getSystemService(
+                            ConnectivityManager.class);
+                    return cm.createDiagnosticsManager();
+                }
+        );
+
+        SystemServiceRegistry.registerContextAwareService(
+                Context.TEST_NETWORK_SERVICE,
+                TestNetworkManager.class,
+                context -> {
+                    final ConnectivityManager cm = context.getSystemService(
+                            ConnectivityManager.class);
+                    return cm.startOrGetTestNetworkManager();
+                }
+        );
+    }
+}
diff --git a/framework/src/android/net/ConnectivityManager.java b/framework/src/android/net/ConnectivityManager.java
index 7f07bba..0976b75 100644
--- a/framework/src/android/net/ConnectivityManager.java
+++ b/framework/src/android/net/ConnectivityManager.java
@@ -21,6 +21,7 @@
 import static android.net.NetworkRequest.Type.LISTEN;
 import static android.net.NetworkRequest.Type.REQUEST;
 import static android.net.NetworkRequest.Type.TRACK_DEFAULT;
+import static android.net.NetworkRequest.Type.TRACK_SYSTEM_DEFAULT;
 import static android.net.QosCallback.QosCallbackRegistrationException;
 
 import android.annotation.CallbackExecutor;
@@ -1368,7 +1369,7 @@
     public NetworkCapabilities[] getDefaultNetworkCapabilitiesForUser(int userId) {
         try {
             return mService.getDefaultNetworkCapabilitiesForUser(
-                    userId, mContext.getOpPackageName());
+                    userId, mContext.getOpPackageName(), getAttributionTag());
         } catch (RemoteException e) {
             throw e.rethrowFromSystemServer();
         }
@@ -1450,7 +1451,8 @@
     @Nullable
     public NetworkCapabilities getNetworkCapabilities(@Nullable Network network) {
         try {
-            return mService.getNetworkCapabilities(network, mContext.getOpPackageName());
+            return mService.getNetworkCapabilities(
+                    network, mContext.getOpPackageName(), getAttributionTag());
         } catch (RemoteException e) {
             throw e.rethrowFromSystemServer();
         }
@@ -2142,7 +2144,7 @@
      */
     // TODO: Remove method and replace with direct call once R code is pushed to AOSP
     private @Nullable String getAttributionTag() {
-        return null;
+        return mContext.getAttributionTag();
     }
 
     /**
@@ -3231,32 +3233,6 @@
         }
     }
 
-    /** {@hide} - returns the factory serial number */
-    @UnsupportedAppUsage
-    @RequiresPermission(anyOf = {
-            NetworkStack.PERMISSION_MAINLINE_NETWORK_STACK,
-            android.Manifest.permission.NETWORK_FACTORY})
-    public int registerNetworkFactory(Messenger messenger, String name) {
-        try {
-            return mService.registerNetworkFactory(messenger, name);
-        } catch (RemoteException e) {
-            throw e.rethrowFromSystemServer();
-        }
-    }
-
-    /** {@hide} */
-    @UnsupportedAppUsage(maxTargetSdk = Build.VERSION_CODES.P, trackingBug = 115609023)
-    @RequiresPermission(anyOf = {
-            NetworkStack.PERMISSION_MAINLINE_NETWORK_STACK,
-            android.Manifest.permission.NETWORK_FACTORY})
-    public void unregisterNetworkFactory(Messenger messenger) {
-        try {
-            mService.unregisterNetworkFactory(messenger);
-        } catch (RemoteException e) {
-            throw e.rethrowFromSystemServer();
-        }
-    }
-
     /**
      * Registers the specified {@link NetworkProvider}.
      * Each listener must only be registered once. The listener can be unregistered with
@@ -3746,7 +3722,8 @@
         printStackTrace();
         checkCallbackNotNull(callback);
         Preconditions.checkArgument(
-                reqType == TRACK_DEFAULT || need != null, "null NetworkCapabilities");
+                reqType == TRACK_DEFAULT || reqType == TRACK_SYSTEM_DEFAULT || need != null,
+                "null NetworkCapabilities");
         final NetworkRequest request;
         final String callingPackageName = mContext.getOpPackageName();
         try {
@@ -3761,7 +3738,8 @@
                 Binder binder = new Binder();
                 if (reqType == LISTEN) {
                     request = mService.listenForNetwork(
-                            need, messenger, binder, callingPackageName);
+                            need, messenger, binder, callingPackageName,
+                            getAttributionTag());
                 } else {
                     request = mService.requestNetwork(
                             need, reqType.ordinal(), messenger, timeoutMs, binder, legacyType,
@@ -4206,7 +4184,8 @@
         checkPendingIntentNotNull(operation);
         try {
             mService.pendingListenForNetwork(
-                    request.networkCapabilities, operation, mContext.getOpPackageName());
+                    request.networkCapabilities, operation, mContext.getOpPackageName(),
+                    getAttributionTag());
         } catch (RemoteException e) {
             throw e.rethrowFromSystemServer();
         } catch (ServiceSpecificException e) {
@@ -4215,8 +4194,9 @@
     }
 
     /**
-     * Registers to receive notifications about changes in the system default network. The callbacks
-     * will continue to be called until either the application exits or
+     * Registers to receive notifications about changes in the application's default network. This
+     * may be a physical network or a virtual network, such as a VPN that applies to the
+     * application. The callbacks will continue to be called until either the application exits or
      * {@link #unregisterNetworkCallback(NetworkCallback)} is called.
      *
      * <p>To avoid performance issues due to apps leaking callbacks, the system will limit the
@@ -4229,7 +4209,7 @@
      * {@link #unregisterNetworkCallback(NetworkCallback)}.
      *
      * @param networkCallback The {@link NetworkCallback} that the system will call as the
-     *                        system default network changes.
+     *                        application's default network changes.
      *                        The callback is invoked on the default internal Handler.
      * @throws RuntimeException if the app already has too many callbacks registered.
      */
@@ -4239,10 +4219,46 @@
     }
 
     /**
+     * Registers to receive notifications about changes in the application's default network. This
+     * may be a physical network or a virtual network, such as a VPN that applies to the
+     * application. The callbacks will continue to be called until either the application exits or
+     * {@link #unregisterNetworkCallback(NetworkCallback)} is called.
+     *
+     * <p>To avoid performance issues due to apps leaking callbacks, the system will limit the
+     * number of outstanding requests to 100 per app (identified by their UID), shared with
+     * all variants of this method, of {@link #requestNetwork} as well as
+     * {@link ConnectivityDiagnosticsManager#registerConnectivityDiagnosticsCallback}.
+     * Requesting a network with this method will count toward this limit. If this limit is
+     * exceeded, an exception will be thrown. To avoid hitting this issue and to conserve resources,
+     * make sure to unregister the callbacks with
+     * {@link #unregisterNetworkCallback(NetworkCallback)}.
+     *
+     * @param networkCallback The {@link NetworkCallback} that the system will call as the
+     *                        application's default network changes.
+     * @param handler {@link Handler} to specify the thread upon which the callback will be invoked.
+     * @throws RuntimeException if the app already has too many callbacks registered.
+     */
+    @RequiresPermission(android.Manifest.permission.ACCESS_NETWORK_STATE)
+    public void registerDefaultNetworkCallback(@NonNull NetworkCallback networkCallback,
+            @NonNull Handler handler) {
+        CallbackHandler cbHandler = new CallbackHandler(handler);
+        sendRequestForNetwork(null /* NetworkCapabilities need */, networkCallback, 0,
+                TRACK_DEFAULT, TYPE_NONE, cbHandler);
+    }
+
+    /**
      * Registers to receive notifications about changes in the system default network. The callbacks
      * will continue to be called until either the application exits or
      * {@link #unregisterNetworkCallback(NetworkCallback)} is called.
      *
+     * This method should not be used to determine networking state seen by applications, because in
+     * many cases, most or even all application traffic may not use the default network directly,
+     * and traffic from different applications may go on different networks by default. As an
+     * example, if a VPN is connected, traffic from all applications might be sent through the VPN
+     * and not onto the system default network. Applications or system components desiring to do
+     * determine network state as seen by applications should use other methods such as
+     * {@link #registerDefaultNetworkCallback(NetworkCallback, Handler)}.
+     *
      * <p>To avoid performance issues due to apps leaking callbacks, the system will limit the
      * number of outstanding requests to 100 per app (identified by their UID), shared with
      * all variants of this method, of {@link #requestNetwork} as well as
@@ -4256,20 +4272,19 @@
      *                        system default network changes.
      * @param handler {@link Handler} to specify the thread upon which the callback will be invoked.
      * @throws RuntimeException if the app already has too many callbacks registered.
+     *
+     * @hide
      */
-    @RequiresPermission(android.Manifest.permission.ACCESS_NETWORK_STATE)
-    public void registerDefaultNetworkCallback(@NonNull NetworkCallback networkCallback,
+    @SystemApi(client = MODULE_LIBRARIES)
+    @SuppressLint({"ExecutorRegistration", "PairedRegistration"})
+    @RequiresPermission(anyOf = {
+            NetworkStack.PERMISSION_MAINLINE_NETWORK_STACK,
+            android.Manifest.permission.NETWORK_SETTINGS})
+    public void registerSystemDefaultNetworkCallback(@NonNull NetworkCallback networkCallback,
             @NonNull Handler handler) {
-        // This works because if the NetworkCapabilities are null,
-        // ConnectivityService takes them from the default request.
-        //
-        // Since the capabilities are exactly the same as the default request's
-        // capabilities, this request is guaranteed, at all times, to be
-        // satisfied by the same network, if any, that satisfies the default
-        // request, i.e., the system default network.
         CallbackHandler cbHandler = new CallbackHandler(handler);
         sendRequestForNetwork(null /* NetworkCapabilities need */, networkCallback, 0,
-                TRACK_DEFAULT, TYPE_NONE, cbHandler);
+                TRACK_SYSTEM_DEFAULT, TYPE_NONE, cbHandler);
     }
 
     /**
@@ -4823,6 +4838,28 @@
         }
     }
 
+    /** @hide */
+    public TestNetworkManager startOrGetTestNetworkManager() {
+        final IBinder tnBinder;
+        try {
+            tnBinder = mService.startOrGetTestNetworkService();
+        } catch (RemoteException e) {
+            throw e.rethrowFromSystemServer();
+        }
+
+        return new TestNetworkManager(ITestNetworkManager.Stub.asInterface(tnBinder));
+    }
+
+    /** @hide */
+    public VpnManager createVpnManager() {
+        return new VpnManager(mContext, mService);
+    }
+
+    /** @hide */
+    public ConnectivityDiagnosticsManager createDiagnosticsManager() {
+        return new ConnectivityDiagnosticsManager(mContext, mService);
+    }
+
     /**
      * Simulates a Data Stall for the specified Network.
      *
@@ -4849,9 +4886,13 @@
         }
     }
 
-    private void setOemNetworkPreference(@NonNull OemNetworkPreferences preference) {
-        Log.d(TAG, "setOemNetworkPreference called with preference: "
-                + preference.toString());
+    private void setOemNetworkPreference(@NonNull final OemNetworkPreferences preference) {
+        try {
+            mService.setOemNetworkPreference(preference);
+        } catch (RemoteException e) {
+            Log.e(TAG, "setOemNetworkPreference() failed for preference: " + preference.toString());
+            throw e.rethrowFromSystemServer();
+        }
     }
 
     @NonNull
diff --git a/framework/src/android/net/IConnectivityManager.aidl b/framework/src/android/net/IConnectivityManager.aidl
index 1b4d2e4..f909d13 100644
--- a/framework/src/android/net/IConnectivityManager.aidl
+++ b/framework/src/android/net/IConnectivityManager.aidl
@@ -29,6 +29,7 @@
 import android.net.NetworkInfo;
 import android.net.NetworkRequest;
 import android.net.NetworkState;
+import android.net.OemNetworkPreferences;
 import android.net.ProxyInfo;
 import android.net.UidRange;
 import android.net.QosSocketInfo;
@@ -65,7 +66,7 @@
     Network getNetworkForType(int networkType);
     Network[] getAllNetworks();
     NetworkCapabilities[] getDefaultNetworkCapabilitiesForUser(
-            int userId, String callingPackageName);
+            int userId, String callingPackageName, String callingAttributionTag);
 
     boolean isNetworkSupported(int networkType);
 
@@ -74,7 +75,8 @@
     LinkProperties getLinkPropertiesForType(int networkType);
     LinkProperties getLinkProperties(in Network network);
 
-    NetworkCapabilities getNetworkCapabilities(in Network network, String callingPackageName);
+    NetworkCapabilities getNetworkCapabilities(in Network network, String callingPackageName,
+            String callingAttributionTag);
 
     @UnsupportedAppUsage(maxTargetSdk = 30, trackingBug = 170729553)
     NetworkState[] getAllNetworkState();
@@ -156,9 +158,6 @@
 
     boolean requestBandwidthUpdate(in Network network);
 
-    int registerNetworkFactory(in Messenger messenger, in String name);
-    void unregisterNetworkFactory(in Messenger messenger);
-
     int registerNetworkProvider(in Messenger messenger, in String name);
     void unregisterNetworkProvider(in Messenger messenger);
 
@@ -178,10 +177,12 @@
     void releasePendingNetworkRequest(in PendingIntent operation);
 
     NetworkRequest listenForNetwork(in NetworkCapabilities networkCapabilities,
-            in Messenger messenger, in IBinder binder, String callingPackageName);
+            in Messenger messenger, in IBinder binder, String callingPackageName,
+            String callingAttributionTag);
 
     void pendingListenForNetwork(in NetworkCapabilities networkCapabilities,
-            in PendingIntent operation, String callingPackageName);
+            in PendingIntent operation, String callingPackageName,
+            String callingAttributionTag);
 
     void releaseNetworkRequest(in NetworkRequest networkRequest);
 
@@ -243,4 +244,6 @@
 
     void registerQosSocketCallback(in QosSocketInfo socketInfo, in IQosCallback callback);
     void unregisterQosCallback(in IQosCallback callback);
+
+    void setOemNetworkPreference(in OemNetworkPreferences preference);
 }
diff --git a/framework/src/android/net/IpConfiguration.java b/framework/src/android/net/IpConfiguration.java
index 0b20564..d5f8b2e 100644
--- a/framework/src/android/net/IpConfiguration.java
+++ b/framework/src/android/net/IpConfiguration.java
@@ -167,7 +167,7 @@
     }
 
     @Override
-    public boolean equals(Object o) {
+    public boolean equals(@Nullable Object o) {
         if (o == this) {
             return true;
         }
diff --git a/framework/src/android/net/IpPrefix.java b/framework/src/android/net/IpPrefix.java
index e7c8014..bcb65fa 100644
--- a/framework/src/android/net/IpPrefix.java
+++ b/framework/src/android/net/IpPrefix.java
@@ -18,6 +18,7 @@
 
 import android.annotation.IntRange;
 import android.annotation.NonNull;
+import android.annotation.Nullable;
 import android.annotation.SystemApi;
 import android.os.Parcel;
 import android.os.Parcelable;
@@ -124,7 +125,7 @@
      * @return {@code true} if both objects are equal, {@code false} otherwise.
      */
     @Override
-    public boolean equals(Object obj) {
+    public boolean equals(@Nullable Object obj) {
         if (!(obj instanceof IpPrefix)) {
             return false;
         }
diff --git a/framework/src/android/net/LinkAddress.java b/framework/src/android/net/LinkAddress.java
index 44d25a1..d1bdaa0 100644
--- a/framework/src/android/net/LinkAddress.java
+++ b/framework/src/android/net/LinkAddress.java
@@ -349,7 +349,7 @@
      * @return {@code true} if both objects are equal, {@code false} otherwise.
      */
     @Override
-    public boolean equals(Object obj) {
+    public boolean equals(@Nullable Object obj) {
         if (!(obj instanceof LinkAddress)) {
             return false;
         }
diff --git a/framework/src/android/net/LinkProperties.java b/framework/src/android/net/LinkProperties.java
index 486e2d7..e41ed72 100644
--- a/framework/src/android/net/LinkProperties.java
+++ b/framework/src/android/net/LinkProperties.java
@@ -1613,7 +1613,7 @@
      * @return {@code true} if both objects are equal, {@code false} otherwise.
      */
     @Override
-    public boolean equals(Object obj) {
+    public boolean equals(@Nullable Object obj) {
         if (this == obj) return true;
 
         if (!(obj instanceof LinkProperties)) return false;
diff --git a/framework/src/android/net/MacAddress.java b/framework/src/android/net/MacAddress.java
index c7116b4..c83c23a 100644
--- a/framework/src/android/net/MacAddress.java
+++ b/framework/src/android/net/MacAddress.java
@@ -161,7 +161,7 @@
     }
 
     @Override
-    public boolean equals(Object o) {
+    public boolean equals(@Nullable Object o) {
         return (o instanceof MacAddress) && ((MacAddress) o).mAddr == mAddr;
     }
 
diff --git a/framework/src/android/net/Network.java b/framework/src/android/net/Network.java
index b07bd68..46141e0 100644
--- a/framework/src/android/net/Network.java
+++ b/framework/src/android/net/Network.java
@@ -17,6 +17,7 @@
 package android.net;
 
 import android.annotation.NonNull;
+import android.annotation.Nullable;
 import android.annotation.SystemApi;
 import android.compat.annotation.UnsupportedAppUsage;
 import android.os.Build;
@@ -510,7 +511,7 @@
     };
 
     @Override
-    public boolean equals(Object obj) {
+    public boolean equals(@Nullable Object obj) {
         if (!(obj instanceof Network)) return false;
         Network other = (Network)obj;
         return this.netId == other.netId;
diff --git a/framework/src/android/net/NetworkAgent.java b/framework/src/android/net/NetworkAgent.java
index d22d82d..27aa15d 100644
--- a/framework/src/android/net/NetworkAgent.java
+++ b/framework/src/android/net/NetworkAgent.java
@@ -20,6 +20,7 @@
 import android.annotation.IntRange;
 import android.annotation.NonNull;
 import android.annotation.Nullable;
+import android.annotation.SuppressLint;
 import android.annotation.SystemApi;
 import android.compat.annotation.UnsupportedAppUsage;
 import android.content.Context;
@@ -775,7 +776,8 @@
      * @param underlyingNetworks the new list of underlying networks.
      * @see {@link VpnService.Builder#setUnderlyingNetworks(Network[])}
      */
-    public final void setUnderlyingNetworks(@Nullable List<Network> underlyingNetworks) {
+    public final void setUnderlyingNetworks(
+            @SuppressLint("NullableCollection") @Nullable List<Network> underlyingNetworks) {
         final ArrayList<Network> underlyingArray = (underlyingNetworks != null)
                 ? new ArrayList<>(underlyingNetworks) : null;
         queueOrSendMessage(reg -> reg.sendUnderlyingNetworks(underlyingArray));
diff --git a/framework/src/android/net/NetworkCapabilities.java b/framework/src/android/net/NetworkCapabilities.java
index 3843b9a..9d67f0b 100644
--- a/framework/src/android/net/NetworkCapabilities.java
+++ b/framework/src/android/net/NetworkCapabilities.java
@@ -34,9 +34,9 @@
 import android.util.proto.ProtoOutputStream;
 
 import com.android.internal.annotations.VisibleForTesting;
-import com.android.internal.util.ArrayUtils;
 import com.android.internal.util.BitUtils;
 import com.android.internal.util.Preconditions;
+import com.android.net.module.util.CollectionUtils;
 
 import java.lang.annotation.Retention;
 import java.lang.annotation.RetentionPolicy;
@@ -401,11 +401,18 @@
     public static final int NET_CAPABILITY_VEHICLE_INTERNAL = 27;
 
     /**
-     * Indicates that this network is not managed by a Virtual Carrier Network (VCN).
-     *
-     * TODO(b/177299683): Add additional clarifying javadoc.
+     * Indicates that this network is not subsumed by a Virtual Carrier Network (VCN).
+     * <p>
+     * To provide an experience on a VCN similar to a single traditional carrier network, in
+     * some cases the system sets this bit is set by default in application's network requests,
+     * and may choose to remove it at its own discretion when matching the request to a network.
+     * <p>
+     * Applications that want to know about a Virtual Carrier Network's underlying networks,
+     * for example to use them for multipath purposes, should remove this bit from their network
+     * requests ; the system will not add it back once removed.
      * @hide
      */
+    @SystemApi
     public static final int NET_CAPABILITY_NOT_VCN_MANAGED = 28;
 
     private static final int MIN_NET_CAPABILITY = NET_CAPABILITY_MMS;
@@ -755,19 +762,21 @@
         final int originalSignalStrength = mSignalStrength;
         final int originalOwnerUid = getOwnerUid();
         final int[] originalAdministratorUids = getAdministratorUids();
+        final TransportInfo originalTransportInfo = getTransportInfo();
         clearAll();
         mTransportTypes = (originalTransportTypes & TEST_NETWORKS_ALLOWED_TRANSPORTS)
                 | (1 << TRANSPORT_TEST);
         mNetworkCapabilities = originalCapabilities & TEST_NETWORKS_ALLOWED_CAPABILITIES;
         mNetworkSpecifier = originalSpecifier;
         mSignalStrength = originalSignalStrength;
+        mTransportInfo = originalTransportInfo;
 
         // Only retain the owner and administrator UIDs if they match the app registering the remote
         // caller that registered the network.
         if (originalOwnerUid == creatorUid) {
             setOwnerUid(creatorUid);
         }
-        if (ArrayUtils.contains(originalAdministratorUids, creatorUid)) {
+        if (CollectionUtils.contains(originalAdministratorUids, creatorUid)) {
             setAdministratorUids(new int[] {creatorUid});
         }
         // There is no need to clear the UIDs, they have already been cleared by clearAll() above.
@@ -1779,6 +1788,15 @@
         return 0;
     }
 
+    private <T extends Parcelable> void writeParcelableArraySet(Parcel in,
+            @Nullable ArraySet<T> val, int flags) {
+        final int size = (val != null) ? val.size() : -1;
+        in.writeInt(size);
+        for (int i = 0; i < size; i++) {
+            in.writeParcelable(val.valueAt(i), flags);
+        }
+    }
+
     @Override
     public void writeToParcel(Parcel dest, int flags) {
         dest.writeLong(mNetworkCapabilities);
@@ -1789,7 +1807,7 @@
         dest.writeParcelable((Parcelable) mNetworkSpecifier, flags);
         dest.writeParcelable((Parcelable) mTransportInfo, flags);
         dest.writeInt(mSignalStrength);
-        dest.writeArraySet(mUids);
+        writeParcelableArraySet(dest, mUids, flags);
         dest.writeString(mSSID);
         dest.writeBoolean(mPrivateDnsBroken);
         dest.writeIntArray(getAdministratorUids());
@@ -1812,8 +1830,7 @@
                 netCap.mNetworkSpecifier = in.readParcelable(null);
                 netCap.mTransportInfo = in.readParcelable(null);
                 netCap.mSignalStrength = in.readInt();
-                netCap.mUids = (ArraySet<UidRange>) in.readArraySet(
-                        null /* ClassLoader, null for default */);
+                netCap.mUids = readParcelableArraySet(in, null /* ClassLoader, null for default */);
                 netCap.mSSID = in.readString();
                 netCap.mPrivateDnsBroken = in.readBoolean();
                 netCap.setAdministratorUids(in.createIntArray());
@@ -1826,6 +1843,20 @@
             public NetworkCapabilities[] newArray(int size) {
                 return new NetworkCapabilities[size];
             }
+
+            private @Nullable <T extends Parcelable> ArraySet<T> readParcelableArraySet(Parcel in,
+                    @Nullable ClassLoader loader) {
+                final int size = in.readInt();
+                if (size < 0) {
+                    return null;
+                }
+                final ArraySet<T> result = new ArraySet<>(size);
+                for (int i = 0; i < size; i++) {
+                    final T value = in.readParcelable(loader);
+                    result.append(value);
+                }
+                return result;
+            }
         };
 
     @Override
@@ -1873,7 +1904,7 @@
             sb.append(" OwnerUid: ").append(mOwnerUid);
         }
 
-        if (!ArrayUtils.isEmpty(mAdministratorUids)) {
+        if (mAdministratorUids != null && mAdministratorUids.length != 0) {
             sb.append(" AdminUids: ").append(Arrays.toString(mAdministratorUids));
         }
 
@@ -2506,7 +2537,7 @@
         @NonNull
         public NetworkCapabilities build() {
             if (mCaps.getOwnerUid() != Process.INVALID_UID) {
-                if (!ArrayUtils.contains(mCaps.getAdministratorUids(), mCaps.getOwnerUid())) {
+                if (!CollectionUtils.contains(mCaps.getAdministratorUids(), mCaps.getOwnerUid())) {
                     throw new IllegalStateException("The owner UID must be included in "
                             + " administrator UIDs.");
                 }
diff --git a/framework/src/android/net/NetworkRequest.java b/framework/src/android/net/NetworkRequest.java
index 04011fc..b4a651c 100644
--- a/framework/src/android/net/NetworkRequest.java
+++ b/framework/src/android/net/NetworkRequest.java
@@ -16,6 +16,22 @@
 
 package android.net;
 
+import static android.net.NetworkCapabilities.NET_CAPABILITY_CAPTIVE_PORTAL;
+import static android.net.NetworkCapabilities.NET_CAPABILITY_DUN;
+import static android.net.NetworkCapabilities.NET_CAPABILITY_FOREGROUND;
+import static android.net.NetworkCapabilities.NET_CAPABILITY_INTERNET;
+import static android.net.NetworkCapabilities.NET_CAPABILITY_NOT_CONGESTED;
+import static android.net.NetworkCapabilities.NET_CAPABILITY_NOT_METERED;
+import static android.net.NetworkCapabilities.NET_CAPABILITY_NOT_RESTRICTED;
+import static android.net.NetworkCapabilities.NET_CAPABILITY_NOT_ROAMING;
+import static android.net.NetworkCapabilities.NET_CAPABILITY_NOT_SUSPENDED;
+import static android.net.NetworkCapabilities.NET_CAPABILITY_NOT_VCN_MANAGED;
+import static android.net.NetworkCapabilities.NET_CAPABILITY_NOT_VPN;
+import static android.net.NetworkCapabilities.NET_CAPABILITY_PARTIAL_CONNECTIVITY;
+import static android.net.NetworkCapabilities.NET_CAPABILITY_TEMPORARILY_NOT_METERED;
+import static android.net.NetworkCapabilities.NET_CAPABILITY_TRUSTED;
+import static android.net.NetworkCapabilities.NET_CAPABILITY_VALIDATED;
+
 import android.annotation.NonNull;
 import android.annotation.Nullable;
 import android.annotation.RequiresPermission;
@@ -30,6 +46,8 @@
 import android.text.TextUtils;
 import android.util.proto.ProtoOutputStream;
 
+import java.util.Arrays;
+import java.util.List;
 import java.util.Objects;
 import java.util.Set;
 
@@ -86,17 +104,14 @@
      *       callbacks about the single, highest scoring current network
      *       (if any) that matches the specified NetworkCapabilities, or
      *
-     *     - TRACK_DEFAULT, a hybrid of the two designed such that the
-     *       framework will issue callbacks for the single, highest scoring
-     *       current network (if any) that matches the capabilities of the
-     *       default Internet request (mDefaultRequest), but which cannot cause
-     *       the framework to either create or retain the existence of any
-     *       specific network. Note that from the point of view of the request
-     *       matching code, TRACK_DEFAULT is identical to REQUEST: its special
-     *       behaviour is not due to different semantics, but to the fact that
-     *       the system will only ever create a TRACK_DEFAULT with capabilities
-     *       that are identical to the default request's capabilities, thus
-     *       causing it to share fate in every way with the default request.
+     *     - TRACK_DEFAULT, which causes the framework to issue callbacks for
+     *       the single, highest scoring current network (if any) that will
+     *       be chosen for an app, but which cannot cause the framework to
+     *       either create or retain the existence of any specific network.
+     *
+     *     - TRACK_SYSTEM_DEFAULT, which causes the framework to send callbacks
+     *       for the network (if any) that satisfies the default Internet
+     *       request.
      *
      *     - BACKGROUND_REQUEST, like REQUEST but does not cause any networks
      *       to retain the NET_CAPABILITY_FOREGROUND capability. A network with
@@ -119,6 +134,7 @@
         TRACK_DEFAULT,
         REQUEST,
         BACKGROUND_REQUEST,
+        TRACK_SYSTEM_DEFAULT,
     };
 
     /**
@@ -156,8 +172,30 @@
      * needed in terms of {@link NetworkCapabilities} features
      */
     public static class Builder {
+        /**
+         * Capabilities that are currently compatible with VCN networks.
+         */
+        private static final List<Integer> VCN_SUPPORTED_CAPABILITIES = Arrays.asList(
+                NET_CAPABILITY_CAPTIVE_PORTAL,
+                NET_CAPABILITY_DUN,
+                NET_CAPABILITY_FOREGROUND,
+                NET_CAPABILITY_INTERNET,
+                NET_CAPABILITY_NOT_CONGESTED,
+                NET_CAPABILITY_NOT_METERED,
+                NET_CAPABILITY_NOT_RESTRICTED,
+                NET_CAPABILITY_NOT_ROAMING,
+                NET_CAPABILITY_NOT_SUSPENDED,
+                NET_CAPABILITY_NOT_VPN,
+                NET_CAPABILITY_PARTIAL_CONNECTIVITY,
+                NET_CAPABILITY_TEMPORARILY_NOT_METERED,
+                NET_CAPABILITY_TRUSTED,
+                NET_CAPABILITY_VALIDATED);
+
         private final NetworkCapabilities mNetworkCapabilities;
 
+        // A boolean that represents the user modified NOT_VCN_MANAGED capability.
+        private boolean mModifiedNotVcnManaged = false;
+
         /**
          * Default constructor for Builder.
          */
@@ -179,6 +217,7 @@
             // maybeMarkCapabilitiesRestricted() doesn't add back.
             final NetworkCapabilities nc = new NetworkCapabilities(mNetworkCapabilities);
             nc.maybeMarkCapabilitiesRestricted();
+            deduceNotVcnManagedCapability(nc);
             return new NetworkRequest(nc, ConnectivityManager.TYPE_NONE,
                     ConnectivityManager.REQUEST_ID_UNSET, Type.NONE);
         }
@@ -195,6 +234,9 @@
          */
         public Builder addCapability(@NetworkCapabilities.NetCapability int capability) {
             mNetworkCapabilities.addCapability(capability);
+            if (capability == NetworkCapabilities.NET_CAPABILITY_NOT_VCN_MANAGED) {
+                mModifiedNotVcnManaged = true;
+            }
             return this;
         }
 
@@ -206,6 +248,9 @@
          */
         public Builder removeCapability(@NetworkCapabilities.NetCapability int capability) {
             mNetworkCapabilities.removeCapability(capability);
+            if (capability == NetworkCapabilities.NET_CAPABILITY_NOT_VCN_MANAGED) {
+                mModifiedNotVcnManaged = true;
+            }
             return this;
         }
 
@@ -263,6 +308,9 @@
         @NonNull
         public Builder clearCapabilities() {
             mNetworkCapabilities.clearAll();
+            // If the caller explicitly clear all capabilities, the NOT_VCN_MANAGED capabilities
+            // should not be add back later.
+            mModifiedNotVcnManaged = true;
             return this;
         }
 
@@ -382,6 +430,25 @@
             mNetworkCapabilities.setSignalStrength(signalStrength);
             return this;
         }
+
+        /**
+         * Deduce the NET_CAPABILITY_NOT_VCN_MANAGED capability from other capabilities
+         * and user intention, which includes:
+         *   1. For the requests that don't have anything besides
+         *      {@link #VCN_SUPPORTED_CAPABILITIES}, add the NET_CAPABILITY_NOT_VCN_MANAGED to
+         *      allow the callers automatically utilize VCN networks if available.
+         *   2. For the requests that explicitly add or remove NET_CAPABILITY_NOT_VCN_MANAGED,
+         *      do not alter them to allow user fire request that suits their need.
+         *
+         * @hide
+         */
+        private void deduceNotVcnManagedCapability(final NetworkCapabilities nc) {
+            if (mModifiedNotVcnManaged) return;
+            for (final int cap : nc.getCapabilities()) {
+                if (!VCN_SUPPORTED_CAPABILITIES.contains(cap)) return;
+            }
+            nc.addCapability(NET_CAPABILITY_NOT_VCN_MANAGED);
+        }
     }
 
     // implement the Parcelable interface
@@ -435,25 +502,7 @@
      * @hide
      */
     public boolean isRequest() {
-        return isForegroundRequest() || isBackgroundRequest();
-    }
-
-    /**
-     * Returns true iff. the contained NetworkRequest is one that:
-     *
-     *     - should be associated with at most one satisfying network
-     *       at a time;
-     *
-     *     - should cause a network to be kept up and in the foreground if
-     *       it is the best network which can satisfy the NetworkRequest.
-     *
-     * For full detail of how isRequest() is used for pairing Networks with
-     * NetworkRequests read rematchNetworkAndRequests().
-     *
-     * @hide
-     */
-    public boolean isForegroundRequest() {
-        return type == Type.TRACK_DEFAULT || type == Type.REQUEST;
+        return type == Type.REQUEST || type == Type.BACKGROUND_REQUEST;
     }
 
     /**
@@ -550,6 +599,8 @@
                 return NetworkRequestProto.TYPE_REQUEST;
             case BACKGROUND_REQUEST:
                 return NetworkRequestProto.TYPE_BACKGROUND_REQUEST;
+            case TRACK_SYSTEM_DEFAULT:
+                return NetworkRequestProto.TYPE_TRACK_SYSTEM_DEFAULT;
             default:
                 return NetworkRequestProto.TYPE_UNKNOWN;
         }
@@ -567,7 +618,7 @@
         proto.end(token);
     }
 
-    public boolean equals(Object obj) {
+    public boolean equals(@Nullable Object obj) {
         if (obj instanceof NetworkRequest == false) return false;
         NetworkRequest that = (NetworkRequest)obj;
         return (that.legacyType == this.legacyType &&
diff --git a/framework/src/android/net/Proxy.java b/framework/src/android/net/Proxy.java
index 03b07e0..9cd7ab2 100644
--- a/framework/src/android/net/Proxy.java
+++ b/framework/src/android/net/Proxy.java
@@ -30,8 +30,6 @@
 import java.net.ProxySelector;
 import java.net.URI;
 import java.util.List;
-import java.util.regex.Matcher;
-import java.util.regex.Pattern;
 
 /**
  * A convenience class for accessing the user and default proxy
@@ -64,40 +62,9 @@
     @Deprecated
     public static final String EXTRA_PROXY_INFO = "android.intent.extra.PROXY_INFO";
 
-    /** @hide */
-    public static final int PROXY_VALID             = 0;
-    /** @hide */
-    public static final int PROXY_HOSTNAME_EMPTY    = 1;
-    /** @hide */
-    public static final int PROXY_HOSTNAME_INVALID  = 2;
-    /** @hide */
-    public static final int PROXY_PORT_EMPTY        = 3;
-    /** @hide */
-    public static final int PROXY_PORT_INVALID      = 4;
-    /** @hide */
-    public static final int PROXY_EXCLLIST_INVALID  = 5;
-
     private static ConnectivityManager sConnectivityManager = null;
 
-    // Hostname / IP REGEX validation
-    // Matches blank input, ips, and domain names
-    private static final String NAME_IP_REGEX =
-        "[a-zA-Z0-9]+(\\-[a-zA-Z0-9]+)*(\\.[a-zA-Z0-9]+(\\-[a-zA-Z0-9]+)*)*";
-
-    private static final String HOSTNAME_REGEXP = "^$|^" + NAME_IP_REGEX + "$";
-
-    private static final Pattern HOSTNAME_PATTERN;
-
-    private static final String EXCL_REGEX =
-        "[a-zA-Z0-9*]+(\\-[a-zA-Z0-9*]+)*(\\.[a-zA-Z0-9*]+(\\-[a-zA-Z0-9*]+)*)*";
-
-    private static final String EXCLLIST_REGEXP = "^$|^" + EXCL_REGEX + "(," + EXCL_REGEX + ")*$";
-
-    private static final Pattern EXCLLIST_PATTERN;
-
     static {
-        HOSTNAME_PATTERN = Pattern.compile(HOSTNAME_REGEXP);
-        EXCLLIST_PATTERN = Pattern.compile(EXCLLIST_REGEXP);
         sDefaultProxySelector = ProxySelector.getDefault();
     }
 
@@ -216,33 +183,6 @@
         return false;
     }
 
-    /**
-     * Validate syntax of hostname, port and exclusion list entries
-     * {@hide}
-     */
-    public static int validate(String hostname, String port, String exclList) {
-        Matcher match = HOSTNAME_PATTERN.matcher(hostname);
-        Matcher listMatch = EXCLLIST_PATTERN.matcher(exclList);
-
-        if (!match.matches()) return PROXY_HOSTNAME_INVALID;
-
-        if (!listMatch.matches()) return PROXY_EXCLLIST_INVALID;
-
-        if (hostname.length() > 0 && port.length() == 0) return PROXY_PORT_EMPTY;
-
-        if (port.length() > 0) {
-            if (hostname.length() == 0) return PROXY_HOSTNAME_EMPTY;
-            int portVal = -1;
-            try {
-                portVal = Integer.parseInt(port);
-            } catch (NumberFormatException ex) {
-                return PROXY_PORT_INVALID;
-            }
-            if (portVal <= 0 || portVal > 0xFFFF) return PROXY_PORT_INVALID;
-        }
-        return PROXY_VALID;
-    }
-
     /** @hide */
     @UnsupportedAppUsage(maxTargetSdk = Build.VERSION_CODES.R, trackingBug = 170729553)
     public static final void setHttpProxySystemProperty(ProxyInfo p) {
diff --git a/framework/src/android/net/ProxyInfo.java b/framework/src/android/net/ProxyInfo.java
index c9bca28..229db0d 100644
--- a/framework/src/android/net/ProxyInfo.java
+++ b/framework/src/android/net/ProxyInfo.java
@@ -23,6 +23,8 @@
 import android.os.Parcelable;
 import android.text.TextUtils;
 
+import com.android.net.module.util.ProxyUtils;
+
 import java.net.InetSocketAddress;
 import java.net.URLConnection;
 import java.util.List;
@@ -233,7 +235,7 @@
      */
     public boolean isValid() {
         if (!Uri.EMPTY.equals(mPacFileUrl)) return true;
-        return Proxy.PROXY_VALID == Proxy.validate(mHost == null ? "" : mHost,
+        return ProxyUtils.PROXY_VALID == ProxyUtils.validate(mHost == null ? "" : mHost,
                 mPort == 0 ? "" : Integer.toString(mPort),
                 mExclusionList == null ? "" : mExclusionList);
     }
@@ -275,7 +277,7 @@
     }
 
     @Override
-    public boolean equals(Object o) {
+    public boolean equals(@Nullable Object o) {
         if (!(o instanceof ProxyInfo)) return false;
         ProxyInfo p = (ProxyInfo)o;
         // If PAC URL is present in either then they must be equal.
diff --git a/framework/src/android/net/RouteInfo.java b/framework/src/android/net/RouteInfo.java
index 94f849f..5b6684a 100644
--- a/framework/src/android/net/RouteInfo.java
+++ b/framework/src/android/net/RouteInfo.java
@@ -534,7 +534,7 @@
      * Compares this RouteInfo object against the specified object and indicates if they are equal.
      * @return {@code true} if the objects are equal, {@code false} otherwise.
      */
-    public boolean equals(Object obj) {
+    public boolean equals(@Nullable Object obj) {
         if (this == obj) return true;
 
         if (!(obj instanceof RouteInfo)) return false;
@@ -570,7 +570,7 @@
         }
 
         @Override
-        public boolean equals(Object o) {
+        public boolean equals(@Nullable Object o) {
             if (!(o instanceof RouteKey)) {
                 return false;
             }
diff --git a/framework/src/android/net/VpnManager.java b/framework/src/android/net/VpnManager.java
index c87b827..1e30283 100644
--- a/framework/src/android/net/VpnManager.java
+++ b/framework/src/android/net/VpnManager.java
@@ -21,6 +21,7 @@
 import android.annotation.IntDef;
 import android.annotation.NonNull;
 import android.annotation.Nullable;
+import android.annotation.UserIdInt;
 import android.app.Activity;
 import android.content.ComponentName;
 import android.content.Context;
@@ -28,6 +29,8 @@
 import android.content.res.Resources;
 import android.os.RemoteException;
 
+import com.android.internal.net.LegacyVpnInfo;
+import com.android.internal.net.VpnConfig;
 import com.android.internal.net.VpnProfile;
 
 import java.io.IOException;
@@ -52,13 +55,29 @@
 public class VpnManager {
     /** Type representing a lack of VPN @hide */
     public static final int TYPE_VPN_NONE = -1;
-    /** VPN service type code @hide */
+
+    /**
+     * A VPN created by an app using the {@link VpnService} API.
+     * @hide
+     */
     public static final int TYPE_VPN_SERVICE = 1;
-    /** Platform VPN type code @hide */
+
+    /**
+     * A VPN created using a {@link VpnManager} API such as {@link #startProvisionedVpnProfile}.
+     * @hide
+     */
     public static final int TYPE_VPN_PLATFORM = 2;
 
+    /**
+     * An IPsec VPN created by the built-in LegacyVpnRunner.
+     * @deprecated new Android devices should use VPN_TYPE_PLATFORM instead.
+     * @hide
+     */
+    @Deprecated
+    public static final int TYPE_VPN_LEGACY = 3;
+
     /** @hide */
-    @IntDef(value = {TYPE_VPN_NONE, TYPE_VPN_SERVICE, TYPE_VPN_PLATFORM})
+    @IntDef(value = {TYPE_VPN_NONE, TYPE_VPN_SERVICE, TYPE_VPN_PLATFORM, TYPE_VPN_LEGACY})
     @Retention(RetentionPolicy.SOURCE)
     public @interface VpnType {}
 
@@ -161,4 +180,104 @@
             throw e.rethrowFromSystemServer();
         }
     }
-}
+
+    /**
+     * Return the VPN configuration for the given user ID.
+     * @hide
+     */
+    @Nullable
+    public VpnConfig getVpnConfig(@UserIdInt int userId) {
+        try {
+            return mService.getVpnConfig(userId);
+        } catch (RemoteException e) {
+            throw e.rethrowFromSystemServer();
+        }
+    }
+
+    /**
+     * Prepare for a VPN application.
+     * VPN permissions are checked in the {@link Vpn} class. If the caller is not {@code userId},
+     * {@link android.Manifest.permission.INTERACT_ACROSS_USERS_FULL} permission is required.
+     *
+     * @param oldPackage Package name of the application which currently controls VPN, which will
+     *                   be replaced. If there is no such application, this should should either be
+     *                   {@code null} or {@link VpnConfig.LEGACY_VPN}.
+     * @param newPackage Package name of the application which should gain control of VPN, or
+     *                   {@code null} to disable.
+     * @param userId User for whom to prepare the new VPN.
+     *
+     * @hide
+     */
+    public boolean prepareVpn(@Nullable String oldPackage, @Nullable String newPackage,
+            int userId) {
+        try {
+            return mService.prepareVpn(oldPackage, newPackage, userId);
+        } catch (RemoteException e) {
+            throw e.rethrowFromSystemServer();
+        }
+    }
+
+    /**
+     * Set whether the VPN package has the ability to launch VPNs without user intervention. This
+     * method is used by system-privileged apps. VPN permissions are checked in the {@link Vpn}
+     * class. If the caller is not {@code userId}, {@link
+     * android.Manifest.permission.INTERACT_ACROSS_USERS_FULL} permission is required.
+     *
+     * @param packageName The package for which authorization state should change.
+     * @param userId User for whom {@code packageName} is installed.
+     * @param vpnType The {@link VpnManager.VpnType} constant representing what class of VPN
+     *     permissions should be granted. When unauthorizing an app, {@link
+     *     VpnManager.TYPE_VPN_NONE} should be used.
+     * @hide
+     */
+    public void setVpnPackageAuthorization(
+            String packageName, int userId, @VpnManager.VpnType int vpnType) {
+        try {
+            mService.setVpnPackageAuthorization(packageName, userId, vpnType);
+        } catch (RemoteException e) {
+            throw e.rethrowFromSystemServer();
+        }
+    }
+
+    /**
+     * Return the legacy VPN information for the specified user ID.
+     * @hide
+     */
+    public LegacyVpnInfo getLegacyVpnInfo(@UserIdInt int userId) {
+        try {
+            return mService.getLegacyVpnInfo(userId);
+        } catch (RemoteException e) {
+            throw e.rethrowFromSystemServer();
+        }
+    }
+
+    /**
+     * Starts a legacy VPN.
+     * @hide
+     */
+    public void startLegacyVpn(VpnProfile profile) {
+        try {
+            mService.startLegacyVpn(profile);
+        } catch (RemoteException e) {
+            throw e.rethrowFromSystemServer();
+        }
+    }
+
+    /**
+     * Informs the service that legacy lockdown VPN state should be updated (e.g., if its keystore
+     * entry has been updated). If the LockdownVpn mechanism is enabled, updates the vpn
+     * with a reload of its profile.
+     *
+     * <p>This method can only be called by the system UID
+     * @return a boolean indicating success
+     *
+     * @hide
+     */
+    public boolean updateLockdownVpn() {
+        try {
+            return mService.updateLockdownVpn();
+        } catch (RemoteException e) {
+            throw e.rethrowFromSystemServer();
+        }
+    }
+}
\ No newline at end of file
diff --git a/service/Android.bp b/service/Android.bp
index c8f3bd3..8fc3181 100644
--- a/service/Android.bp
+++ b/service/Android.bp
@@ -57,6 +57,7 @@
     static_libs: [
         "net-utils-device-common",
         "net-utils-framework-common",
+        "netd-client",
     ],
     apex_available: [
         "//apex_available:platform",