Merge "Use TransformRecord to get SPI instead of SpiRecord"
diff --git a/core/java/android/app/usage/NetworkStatsManager.java b/core/java/android/app/usage/NetworkStatsManager.java
index 8e40449..d6e7762 100644
--- a/core/java/android/app/usage/NetworkStatsManager.java
+++ b/core/java/android/app/usage/NetworkStatsManager.java
@@ -16,19 +16,23 @@
 
 package android.app.usage;
 
-import static com.android.internal.util.Preconditions.checkNotNull;
-
+import android.annotation.NonNull;
 import android.annotation.Nullable;
+import android.annotation.RequiresPermission;
+import android.annotation.SystemApi;
 import android.annotation.SystemService;
 import android.annotation.TestApi;
-import android.annotation.UnsupportedAppUsage;
 import android.app.usage.NetworkStats.Bucket;
+import android.compat.annotation.UnsupportedAppUsage;
 import android.content.Context;
 import android.net.ConnectivityManager;
 import android.net.DataUsageRequest;
 import android.net.INetworkStatsService;
 import android.net.NetworkIdentity;
+import android.net.NetworkStack;
 import android.net.NetworkTemplate;
+import android.net.netstats.provider.INetworkStatsProviderCallback;
+import android.net.netstats.provider.NetworkStatsProvider;
 import android.os.Binder;
 import android.os.Handler;
 import android.os.Looper;
@@ -42,6 +46,8 @@
 
 import com.android.internal.annotations.VisibleForTesting;
 
+import java.util.Objects;
+
 /**
  * Provides access to network usage history and statistics. Usage data is collected in
  * discrete bins of time called 'Buckets'. See {@link NetworkStats.Bucket} for details.
@@ -146,6 +152,7 @@
     }
 
     /** @hide */
+    @UnsupportedAppUsage
     @TestApi
     public void setPollForce(boolean pollForce) {
         if (pollForce) {
@@ -417,7 +424,7 @@
     /** @hide */
     public void registerUsageCallback(NetworkTemplate template, int networkType,
             long thresholdBytes, UsageCallback callback, @Nullable Handler handler) {
-        checkNotNull(callback, "UsageCallback cannot be null");
+        Objects.requireNonNull(callback, "UsageCallback cannot be null");
 
         final Looper looper;
         if (handler == null) {
@@ -518,6 +525,57 @@
         private DataUsageRequest request;
     }
 
+    /**
+     * Registers a custom provider of {@link android.net.NetworkStats} to provide network statistics
+     * to the system. To unregister, invoke {@link #unregisterNetworkStatsProvider}.
+     * Note that no de-duplication of statistics between providers is performed, so each provider
+     * must only report network traffic that is not being reported by any other provider. Also note
+     * that the provider cannot be re-registered after unregistering.
+     *
+     * @param tag a human readable identifier of the custom network stats provider. This is only
+     *            used for debugging.
+     * @param provider the subclass of {@link NetworkStatsProvider} that needs to be
+     *                 registered to the system.
+     * @hide
+     */
+    @SystemApi
+    @RequiresPermission(anyOf = {
+            android.Manifest.permission.NETWORK_STATS_PROVIDER,
+            NetworkStack.PERMISSION_MAINLINE_NETWORK_STACK})
+    @NonNull public void registerNetworkStatsProvider(
+            @NonNull String tag,
+            @NonNull NetworkStatsProvider provider) {
+        try {
+            if (provider.getProviderCallbackBinder() != null) {
+                throw new IllegalArgumentException("provider is already registered");
+            }
+            final INetworkStatsProviderCallback cbBinder =
+                    mService.registerNetworkStatsProvider(tag, provider.getProviderBinder());
+            provider.setProviderCallbackBinder(cbBinder);
+        } catch (RemoteException e) {
+            e.rethrowAsRuntimeException();
+        }
+    }
+
+    /**
+     * Unregisters an instance of {@link NetworkStatsProvider}.
+     *
+     * @param provider the subclass of {@link NetworkStatsProvider} that needs to be
+     *                 unregistered to the system.
+     * @hide
+     */
+    @SystemApi
+    @RequiresPermission(anyOf = {
+            android.Manifest.permission.NETWORK_STATS_PROVIDER,
+            NetworkStack.PERMISSION_MAINLINE_NETWORK_STACK})
+    @NonNull public void unregisterNetworkStatsProvider(@NonNull NetworkStatsProvider provider) {
+        try {
+            provider.getProviderCallbackBinderOrThrow().unregister();
+        } catch (RemoteException e) {
+            e.rethrowAsRuntimeException();
+        }
+    }
+
     private static NetworkTemplate createTemplate(int networkType, String subscriberId) {
         final NetworkTemplate template;
         switch (networkType) {
diff --git a/core/java/android/net/EthernetManager.java b/core/java/android/net/EthernetManager.java
index 7256502..d975017 100644
--- a/core/java/android/net/EthernetManager.java
+++ b/core/java/android/net/EthernetManager.java
@@ -16,20 +16,28 @@
 
 package android.net;
 
+import android.annotation.NonNull;
+import android.annotation.RequiresPermission;
+import android.annotation.SystemApi;
 import android.annotation.SystemService;
-import android.annotation.UnsupportedAppUsage;
+import android.annotation.TestApi;
+import android.compat.annotation.UnsupportedAppUsage;
 import android.content.Context;
 import android.os.Handler;
 import android.os.Message;
 import android.os.RemoteException;
 
 import java.util.ArrayList;
+import java.util.Objects;
+import java.util.concurrent.Executor;
 
 /**
  * A class representing the IP configuration of the Ethernet network.
  *
  * @hide
  */
+@SystemApi
+@TestApi
 @SystemService(Context.ETHERNET_SERVICE)
 public class EthernetManager {
     private static final String TAG = "EthernetManager";
@@ -37,7 +45,7 @@
 
     private final Context mContext;
     private final IEthernetManager mService;
-    private final Handler mHandler = new Handler() {
+    private final Handler mHandler = new Handler(ConnectivityThread.getInstanceLooper()) {
         @Override
         public void handleMessage(Message msg) {
             if (msg.what == MSG_AVAILABILITY_CHANGED) {
@@ -60,12 +68,14 @@
 
     /**
      * A listener interface to receive notification on changes in Ethernet.
+     * @hide
      */
     public interface Listener {
         /**
          * Called when Ethernet port's availability is changed.
          * @param iface Ethernet interface name
          * @param isAvailable {@code true} if Ethernet port exists.
+         * @hide
          */
         @UnsupportedAppUsage
         void onAvailabilityChanged(String iface, boolean isAvailable);
@@ -76,6 +86,7 @@
      * Applications will almost always want to use
      * {@link android.content.Context#getSystemService Context.getSystemService()} to retrieve
      * the standard {@link android.content.Context#ETHERNET_SERVICE Context.ETHERNET_SERVICE}.
+     * @hide
      */
     public EthernetManager(Context context, IEthernetManager service) {
         mContext = context;
@@ -85,6 +96,7 @@
     /**
      * Get Ethernet configuration.
      * @return the Ethernet Configuration, contained in {@link IpConfiguration}.
+     * @hide
      */
     @UnsupportedAppUsage
     public IpConfiguration getConfiguration(String iface) {
@@ -97,6 +109,7 @@
 
     /**
      * Set Ethernet configuration.
+     * @hide
      */
     @UnsupportedAppUsage
     public void setConfiguration(String iface, IpConfiguration config) {
@@ -109,6 +122,7 @@
 
     /**
      * Indicates whether the system currently has one or more Ethernet interfaces.
+     * @hide
      */
     @UnsupportedAppUsage
     public boolean isAvailable() {
@@ -119,6 +133,7 @@
      * Indicates whether the system has given interface.
      *
      * @param iface Ethernet interface name
+     * @hide
      */
     @UnsupportedAppUsage
     public boolean isAvailable(String iface) {
@@ -133,6 +148,7 @@
      * Adds a listener.
      * @param listener A {@link Listener} to add.
      * @throws IllegalArgumentException If the listener is null.
+     * @hide
      */
     @UnsupportedAppUsage
     public void addListener(Listener listener) {
@@ -151,6 +167,7 @@
 
     /**
      * Returns an array of available Ethernet interface names.
+     * @hide
      */
     @UnsupportedAppUsage
     public String[] getAvailableInterfaces() {
@@ -165,6 +182,7 @@
      * Removes a listener.
      * @param listener A {@link Listener} to remove.
      * @throws IllegalArgumentException If the listener is null.
+     * @hide
      */
     @UnsupportedAppUsage
     public void removeListener(Listener listener) {
@@ -180,4 +198,98 @@
             }
         }
     }
+
+    /**
+     * Whether to treat interfaces created by {@link TestNetworkManager#createTapInterface}
+     * as Ethernet interfaces. The effects of this method apply to any test interfaces that are
+     * already present on the system.
+     * @hide
+     */
+    @TestApi
+    public void setIncludeTestInterfaces(boolean include) {
+        try {
+            mService.setIncludeTestInterfaces(include);
+        } catch (RemoteException e) {
+            throw e.rethrowFromSystemServer();
+        }
+    }
+
+    /**
+     * A request for a tethered interface.
+     */
+    public static class TetheredInterfaceRequest {
+        private final IEthernetManager mService;
+        private final ITetheredInterfaceCallback mCb;
+
+        private TetheredInterfaceRequest(@NonNull IEthernetManager service,
+                @NonNull ITetheredInterfaceCallback cb) {
+            this.mService = service;
+            this.mCb = cb;
+        }
+
+        /**
+         * Release the request, causing the interface to revert back from tethering mode if there
+         * is no other requestor.
+         */
+        public void release() {
+            try {
+                mService.releaseTetheredInterface(mCb);
+            } catch (RemoteException e) {
+                e.rethrowFromSystemServer();
+            }
+        }
+    }
+
+    /**
+     * Callback for {@link #requestTetheredInterface(TetheredInterfaceCallback)}.
+     */
+    public interface TetheredInterfaceCallback {
+        /**
+         * Called when the tethered interface is available.
+         * @param iface The name of the interface.
+         */
+        void onAvailable(@NonNull String iface);
+
+        /**
+         * Called when the tethered interface is now unavailable.
+         */
+        void onUnavailable();
+    }
+
+    /**
+     * Request a tethered interface in tethering mode.
+     *
+     * <p>When this method is called and there is at least one ethernet interface available, the
+     * system will designate one to act as a tethered interface. If there is already a tethered
+     * interface, the existing interface will be used.
+     * @param callback A callback to be called once the request has been fulfilled.
+     */
+    @RequiresPermission(anyOf = {
+            android.Manifest.permission.NETWORK_STACK,
+            android.net.NetworkStack.PERMISSION_MAINLINE_NETWORK_STACK
+    })
+    @NonNull
+    public TetheredInterfaceRequest requestTetheredInterface(@NonNull final Executor executor,
+            @NonNull final TetheredInterfaceCallback callback) {
+        Objects.requireNonNull(callback, "Callback must be non-null");
+        Objects.requireNonNull(executor, "Executor must be non-null");
+        final ITetheredInterfaceCallback cbInternal = new ITetheredInterfaceCallback.Stub() {
+            @Override
+            public void onAvailable(String iface) {
+                executor.execute(() -> callback.onAvailable(iface));
+            }
+
+            @Override
+            public void onUnavailable() {
+                executor.execute(() -> callback.onUnavailable());
+            }
+        };
+
+        try {
+            mService.requestTetheredInterface(cbInternal);
+        } catch (RemoteException e) {
+            throw e.rethrowFromSystemServer();
+        }
+        return new TetheredInterfaceRequest(mService, cbInternal);
+    }
 }
diff --git a/core/java/android/net/IEthernetManager.aidl b/core/java/android/net/IEthernetManager.aidl
index 94960b5..e058e5a 100644
--- a/core/java/android/net/IEthernetManager.aidl
+++ b/core/java/android/net/IEthernetManager.aidl
@@ -18,6 +18,7 @@
 
 import android.net.IpConfiguration;
 import android.net.IEthernetServiceListener;
+import android.net.ITetheredInterfaceCallback;
 
 /**
  * Interface that answers queries about, and allows changing
@@ -32,4 +33,7 @@
     boolean isAvailable(String iface);
     void addListener(in IEthernetServiceListener listener);
     void removeListener(in IEthernetServiceListener listener);
+    void setIncludeTestInterfaces(boolean include);
+    void requestTetheredInterface(in ITetheredInterfaceCallback callback);
+    void releaseTetheredInterface(in ITetheredInterfaceCallback callback);
 }
diff --git a/core/java/android/net/INetworkStatsService.aidl b/core/java/android/net/INetworkStatsService.aidl
index 9994f9f..5fa515a 100644
--- a/core/java/android/net/INetworkStatsService.aidl
+++ b/core/java/android/net/INetworkStatsService.aidl
@@ -23,6 +23,8 @@
 import android.net.NetworkStats;
 import android.net.NetworkStatsHistory;
 import android.net.NetworkTemplate;
+import android.net.netstats.provider.INetworkStatsProvider;
+import android.net.netstats.provider.INetworkStatsProviderCallback;
 import android.os.IBinder;
 import android.os.Messenger;
 import com.android.internal.net.VpnInfo;
@@ -89,4 +91,7 @@
     /** Get the total network stats information since boot */
     long getTotalStats(int type);
 
+    /** Registers a network stats provider */
+    INetworkStatsProviderCallback registerNetworkStatsProvider(String tag,
+            in INetworkStatsProvider provider);
 }
diff --git a/core/java/android/net/ITetheredInterfaceCallback.aidl b/core/java/android/net/ITetheredInterfaceCallback.aidl
new file mode 100644
index 0000000..e3d0759
--- /dev/null
+++ b/core/java/android/net/ITetheredInterfaceCallback.aidl
@@ -0,0 +1,23 @@
+/*
+ * Copyright (C) 2020 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;
+
+/** @hide */
+interface ITetheredInterfaceCallback {
+    void onAvailable(in String iface);
+    void onUnavailable();
+}
\ No newline at end of file
diff --git a/core/java/android/net/IpSecManager.java b/core/java/android/net/IpSecManager.java
index 45d0c73..d83715c 100644
--- a/core/java/android/net/IpSecManager.java
+++ b/core/java/android/net/IpSecManager.java
@@ -17,7 +17,6 @@
 
 import static com.android.internal.util.Preconditions.checkNotNull;
 
-import android.annotation.IntDef;
 import android.annotation.NonNull;
 import android.annotation.RequiresFeature;
 import android.annotation.RequiresPermission;
@@ -26,6 +25,7 @@
 import android.annotation.TestApi;
 import android.content.Context;
 import android.content.pm.PackageManager;
+import android.net.annotations.PolicyDirection;
 import android.os.Binder;
 import android.os.ParcelFileDescriptor;
 import android.os.RemoteException;
@@ -41,8 +41,6 @@
 
 import java.io.FileDescriptor;
 import java.io.IOException;
-import java.lang.annotation.Retention;
-import java.lang.annotation.RetentionPolicy;
 import java.net.DatagramSocket;
 import java.net.InetAddress;
 import java.net.Socket;
@@ -53,7 +51,7 @@
  *
  * <p>Note that not all aspects of IPsec are permitted by this API. Applications may create
  * transport mode security associations and apply them to individual sockets. Applications looking
- * to create a VPN should use {@link VpnService}.
+ * to create an IPsec VPN should use {@link VpnManager} and {@link Ikev2VpnProfile}.
  *
  * @see <a href="https://tools.ietf.org/html/rfc4301">RFC 4301, Security Architecture for the
  *     Internet Protocol</a>
@@ -78,11 +76,6 @@
      */
     public static final int DIRECTION_OUT = 1;
 
-    /** @hide */
-    @IntDef(value = {DIRECTION_IN, DIRECTION_OUT})
-    @Retention(RetentionPolicy.SOURCE)
-    public @interface PolicyDirection {}
-
     /**
      * The Security Parameter Index (SPI) 0 indicates an unknown or invalid index.
      *
diff --git a/core/java/android/net/NetworkIdentity.java b/core/java/android/net/NetworkIdentity.java
index ce2de85..4edbcd0 100644
--- a/core/java/android/net/NetworkIdentity.java
+++ b/core/java/android/net/NetworkIdentity.java
@@ -25,7 +25,7 @@
 import android.net.wifi.WifiManager;
 import android.os.Build;
 import android.service.NetworkIdentityProto;
-import android.telephony.TelephonyManager;
+import android.telephony.Annotation.NetworkType;
 import android.util.Slog;
 import android.util.proto.ProtoOutputStream;
 
@@ -40,16 +40,6 @@
 public class NetworkIdentity implements Comparable<NetworkIdentity> {
     private static final String TAG = "NetworkIdentity";
 
-    /**
-     * When enabled, combine all {@link #mSubType} together under
-     * {@link #SUBTYPE_COMBINED}.
-     *
-     * @deprecated we no longer offer to collect statistics on a per-subtype
-     *             basis; this is always disabled.
-     */
-    @Deprecated
-    public static final boolean COMBINE_SUBTYPE_ENABLED = true;
-
     public static final int SUBTYPE_COMBINED = -1;
 
     final int mType;
@@ -64,7 +54,7 @@
             int type, int subType, String subscriberId, String networkId, boolean roaming,
             boolean metered, boolean defaultNetwork) {
         mType = type;
-        mSubType = COMBINE_SUBTYPE_ENABLED ? SUBTYPE_COMBINED : subType;
+        mSubType = subType;
         mSubscriberId = subscriberId;
         mNetworkId = networkId;
         mRoaming = roaming;
@@ -96,10 +86,8 @@
         final StringBuilder builder = new StringBuilder("{");
         builder.append("type=").append(getNetworkTypeName(mType));
         builder.append(", subType=");
-        if (COMBINE_SUBTYPE_ENABLED) {
+        if (mSubType == SUBTYPE_COMBINED) {
             builder.append("COMBINED");
-        } else if (ConnectivityManager.isNetworkTypeMobile(mType)) {
-            builder.append(TelephonyManager.getNetworkTypeName(mSubType));
         } else {
             builder.append(mSubType);
         }
@@ -190,13 +178,14 @@
     }
 
     /**
-     * Build a {@link NetworkIdentity} from the given {@link NetworkState},
-     * assuming that any mobile networks are using the current IMSI.
+     * Build a {@link NetworkIdentity} from the given {@link NetworkState} and {@code subType},
+     * assuming that any mobile networks are using the current IMSI. The subType if applicable,
+     * should be set as one of the TelephonyManager.NETWORK_TYPE_* constants, or
+     * {@link android.telephony.TelephonyManager#NETWORK_TYPE_UNKNOWN} if not.
      */
     public static NetworkIdentity buildNetworkIdentity(Context context, NetworkState state,
-            boolean defaultNetwork) {
+            boolean defaultNetwork, @NetworkType int subType) {
         final int type = state.networkInfo.getType();
-        final int subType = state.networkInfo.getSubtype();
 
         String subscriberId = null;
         String networkId = null;
diff --git a/core/java/android/net/NetworkStats.java b/core/java/android/net/NetworkStats.java
index 6c7aa13..b7fb280 100644
--- a/core/java/android/net/NetworkStats.java
+++ b/core/java/android/net/NetworkStats.java
@@ -18,8 +18,11 @@
 
 import static android.os.Process.CLAT_UID;
 
+import android.annotation.IntDef;
 import android.annotation.NonNull;
-import android.annotation.UnsupportedAppUsage;
+import android.annotation.Nullable;
+import android.annotation.SystemApi;
+import android.compat.annotation.UnsupportedAppUsage;
 import android.os.Parcel;
 import android.os.Parcelable;
 import android.os.SystemClock;
@@ -32,6 +35,8 @@
 
 import java.io.CharArrayWriter;
 import java.io.PrintWriter;
+import java.lang.annotation.Retention;
+import java.lang.annotation.RetentionPolicy;
 import java.util.Arrays;
 import java.util.HashSet;
 import java.util.Map;
@@ -48,61 +53,162 @@
  * @hide
  */
 // @NotThreadSafe
-public class NetworkStats implements Parcelable {
+@SystemApi
+public final class NetworkStats implements Parcelable {
     private static final String TAG = "NetworkStats";
-    /** {@link #iface} value when interface details unavailable. */
-    public static final String IFACE_ALL = null;
+
+    /**
+     * {@link #iface} value when interface details unavailable.
+     * @hide
+     */
+    @Nullable public static final String IFACE_ALL = null;
+
+    /**
+     * Virtual network interface for video telephony. This is for VT data usage counting
+     * purpose.
+     */
+    public static final String IFACE_VT = "vt_data0";
+
     /** {@link #uid} value when UID details unavailable. */
     public static final int UID_ALL = -1;
-    /** {@link #tag} value matching any tag. */
+    /** Special UID value for data usage by tethering. */
+    public static final int UID_TETHERING = -5;
+
+    /**
+     * {@link #tag} value matching any tag.
+     * @hide
+     */
     // TODO: Rename TAG_ALL to TAG_ANY.
     public static final int TAG_ALL = -1;
-    /** {@link #set} value for all sets combined, not including debug sets. */
+    /**
+     * {@link #set} value for all sets combined, not including debug sets.
+     * @hide
+     */
     public static final int SET_ALL = -1;
     /** {@link #set} value where background data is accounted. */
     public static final int SET_DEFAULT = 0;
     /** {@link #set} value where foreground data is accounted. */
     public static final int SET_FOREGROUND = 1;
-    /** All {@link #set} value greater than SET_DEBUG_START are debug {@link #set} values. */
+    /**
+     * All {@link #set} value greater than SET_DEBUG_START are debug {@link #set} values.
+     * @hide
+     */
     public static final int SET_DEBUG_START = 1000;
-    /** Debug {@link #set} value when the VPN stats are moved in. */
+    /**
+     * Debug {@link #set} value when the VPN stats are moved in.
+     * @hide
+     */
     public static final int SET_DBG_VPN_IN = 1001;
-    /** Debug {@link #set} value when the VPN stats are moved out of a vpn UID. */
+    /**
+     * Debug {@link #set} value when the VPN stats are moved out of a vpn UID.
+     * @hide
+     */
     public static final int SET_DBG_VPN_OUT = 1002;
 
-    /** Include all interfaces when filtering */
-    public static final String[] INTERFACES_ALL = null;
+    /** @hide */
+    @Retention(RetentionPolicy.SOURCE)
+    @IntDef(prefix = { "SET_" }, value = {
+            SET_ALL,
+            SET_DEFAULT,
+            SET_FOREGROUND,
+            SET_DEBUG_START,
+            SET_DBG_VPN_IN,
+            SET_DBG_VPN_OUT
+    })
+    public @interface State {
+    }
+
+    /**
+     * Include all interfaces when filtering
+     * @hide
+     */
+    public @Nullable static final String[] INTERFACES_ALL = null;
 
     /** {@link #tag} value for total data across all tags. */
     // TODO: Rename TAG_NONE to TAG_ALL.
     public static final int TAG_NONE = 0;
 
-    /** {@link #metered} value to account for all metered states. */
+    /**
+     * {@link #metered} value to account for all metered states.
+     * @hide
+     */
     public static final int METERED_ALL = -1;
     /** {@link #metered} value where native, unmetered data is accounted. */
     public static final int METERED_NO = 0;
     /** {@link #metered} value where metered data is accounted. */
     public static final int METERED_YES = 1;
 
-    /** {@link #roaming} value to account for all roaming states. */
+    /** @hide */
+    @Retention(RetentionPolicy.SOURCE)
+    @IntDef(prefix = { "METERED_" }, value = {
+            METERED_ALL,
+            METERED_NO,
+            METERED_YES
+    })
+    public @interface Meteredness {
+    }
+
+
+    /**
+     * {@link #roaming} value to account for all roaming states.
+     * @hide
+     */
     public static final int ROAMING_ALL = -1;
     /** {@link #roaming} value where native, non-roaming data is accounted. */
     public static final int ROAMING_NO = 0;
     /** {@link #roaming} value where roaming data is accounted. */
     public static final int ROAMING_YES = 1;
 
-    /** {@link #onDefaultNetwork} value to account for all default network states. */
+    /** @hide */
+    @Retention(RetentionPolicy.SOURCE)
+    @IntDef(prefix = { "ROAMING_" }, value = {
+            ROAMING_ALL,
+            ROAMING_NO,
+            ROAMING_YES
+    })
+    public @interface Roaming {
+    }
+
+    /**
+     * {@link #onDefaultNetwork} value to account for all default network states.
+     * @hide
+     */
     public static final int DEFAULT_NETWORK_ALL = -1;
     /** {@link #onDefaultNetwork} value to account for usage while not the default network. */
     public static final int DEFAULT_NETWORK_NO = 0;
     /** {@link #onDefaultNetwork} value to account for usage while the default network. */
     public static final int DEFAULT_NETWORK_YES = 1;
 
-    /** Denotes a request for stats at the interface level. */
+    /** @hide */
+    @Retention(RetentionPolicy.SOURCE)
+    @IntDef(prefix = { "DEFAULT_NETWORK_" }, value = {
+            DEFAULT_NETWORK_ALL,
+            DEFAULT_NETWORK_NO,
+            DEFAULT_NETWORK_YES
+    })
+    public @interface DefaultNetwork {
+    }
+
+    /**
+     * Denotes a request for stats at the interface level.
+     * @hide
+     */
     public static final int STATS_PER_IFACE = 0;
-    /** Denotes a request for stats at the interface and UID level. */
+    /**
+     * Denotes a request for stats at the interface and UID level.
+     * @hide
+     */
     public static final int STATS_PER_UID = 1;
 
+    /** @hide */
+    @Retention(RetentionPolicy.SOURCE)
+    @IntDef(prefix = { "STATS_PER_" }, value = {
+            STATS_PER_IFACE,
+            STATS_PER_UID
+    })
+    public @interface StatsType {
+    }
+
     private static final String CLATD_INTERFACE_PREFIX = "v4-";
     // Delta between IPv4 header (20b) and IPv6 header (40b).
     // Used for correct stats accounting on clatd interfaces.
@@ -144,62 +250,115 @@
     @UnsupportedAppUsage
     private long[] operations;
 
+    /**
+     * Basic element of network statistics. Contains the number of packets and number of bytes
+     * transferred on both directions in a given set of conditions. See
+     * {@link Entry#Entry(String, int, int, int, int, int, int, long, long, long, long, long)}.
+     *
+     * @hide
+     */
+    @SystemApi
     public static class Entry {
+        /** @hide */
         @UnsupportedAppUsage
         public String iface;
+        /** @hide */
         @UnsupportedAppUsage
         public int uid;
+        /** @hide */
         @UnsupportedAppUsage
         public int set;
+        /** @hide */
         @UnsupportedAppUsage
         public int tag;
         /**
          * Note that this is only populated w/ the default value when read from /proc or written
          * to disk. We merge in the correct value when reporting this value to clients of
          * getSummary().
+         * @hide
          */
         public int metered;
         /**
          * Note that this is only populated w/ the default value when read from /proc or written
          * to disk. We merge in the correct value when reporting this value to clients of
          * getSummary().
+         * @hide
          */
         public int roaming;
         /**
          * Note that this is only populated w/ the default value when read from /proc or written
          * to disk. We merge in the correct value when reporting this value to clients of
          * getSummary().
+         * @hide
          */
         public int defaultNetwork;
+        /** @hide */
         @UnsupportedAppUsage
         public long rxBytes;
+        /** @hide */
         @UnsupportedAppUsage
         public long rxPackets;
+        /** @hide */
         @UnsupportedAppUsage
         public long txBytes;
+        /** @hide */
         @UnsupportedAppUsage
         public long txPackets;
+        /** @hide */
+        @UnsupportedAppUsage
         public long operations;
 
+        /** @hide */
         @UnsupportedAppUsage
         public Entry() {
             this(IFACE_ALL, UID_ALL, SET_DEFAULT, TAG_NONE, 0L, 0L, 0L, 0L, 0L);
         }
 
+        /** @hide */
         public Entry(long rxBytes, long rxPackets, long txBytes, long txPackets, long operations) {
             this(IFACE_ALL, UID_ALL, SET_DEFAULT, TAG_NONE, rxBytes, rxPackets, txBytes, txPackets,
                     operations);
         }
 
+        /** @hide */
         public Entry(String iface, int uid, int set, int tag, long rxBytes, long rxPackets,
                 long txBytes, long txPackets, long operations) {
             this(iface, uid, set, tag, METERED_NO, ROAMING_NO, DEFAULT_NETWORK_NO,
                     rxBytes, rxPackets, txBytes, txPackets, operations);
         }
 
-        public Entry(String iface, int uid, int set, int tag, int metered, int roaming,
-                 int defaultNetwork, long rxBytes, long rxPackets, long txBytes, long txPackets,
-                 long operations) {
+        /**
+         * Construct a {@link Entry} object by giving statistics of packet and byte transferred on
+         * both direction, and associated with a set of given conditions.
+         *
+         * @param iface interface name of this {@link Entry}. Or null if not specified.
+         * @param uid uid of this {@link Entry}. {@link #UID_TETHERING} if this {@link Entry} is
+         *            for tethering. Or {@link #UID_ALL} if this {@link NetworkStats} is only
+         *            counting iface stats.
+         * @param set usage state of this {@link Entry}. Should be one of the following
+         *            values: {@link #SET_DEFAULT}, {@link #SET_FOREGROUND}.
+         * @param tag tag of this {@link Entry}.
+         * @param metered metered state of this {@link Entry}. Should be one of the following
+         *                values: {link #METERED_YES}, {link #METERED_NO}.
+         * @param roaming roaming state of this {@link Entry}. Should be one of the following
+         *                values: {link #ROAMING_YES}, {link #ROAMING_NO}.
+         * @param defaultNetwork default network status of this {@link Entry}. Should be one
+         *                       of the following values: {link #DEFAULT_NETWORK_YES},
+         *                       {link #DEFAULT_NETWORK_NO}.
+         * @param rxBytes Number of bytes received for this {@link Entry}. Statistics should
+         *                represent the contents of IP packets, including IP headers.
+         * @param rxPackets Number of packets received for this {@link Entry}. Statistics should
+         *                  represent the contents of IP packets, including IP headers.
+         * @param txBytes Number of bytes transmitted for this {@link Entry}. Statistics should
+         *                represent the contents of IP packets, including IP headers.
+         * @param txPackets Number of bytes transmitted for this {@link Entry}. Statistics should
+         *                  represent the contents of IP packets, including IP headers.
+         * @param operations count of network operations performed for this {@link Entry}. This can
+         *                   be used to derive bytes-per-operation.
+         */
+        public Entry(@Nullable String iface, int uid, @State int set, int tag,
+                @Meteredness int metered, @Roaming int roaming, @DefaultNetwork int defaultNetwork,
+                long rxBytes, long rxPackets, long txBytes, long txPackets, long operations) {
             this.iface = iface;
             this.uid = uid;
             this.set = set;
@@ -214,15 +373,18 @@
             this.operations = operations;
         }
 
+        /** @hide */
         public boolean isNegative() {
             return rxBytes < 0 || rxPackets < 0 || txBytes < 0 || txPackets < 0 || operations < 0;
         }
 
+        /** @hide */
         public boolean isEmpty() {
             return rxBytes == 0 && rxPackets == 0 && txBytes == 0 && txPackets == 0
                     && operations == 0;
         }
 
+        /** @hide */
         public void add(Entry another) {
             this.rxBytes += another.rxBytes;
             this.rxPackets += another.rxPackets;
@@ -249,6 +411,7 @@
             return builder.toString();
         }
 
+        /** @hide */
         @Override
         public boolean equals(Object o) {
             if (o instanceof Entry) {
@@ -262,13 +425,13 @@
             return false;
         }
 
+        /** @hide */
         @Override
         public int hashCode() {
             return Objects.hash(uid, set, tag, metered, roaming, defaultNetwork, iface);
         }
     }
 
-    @UnsupportedAppUsage
     public NetworkStats(long elapsedRealtime, int initialSize) {
         this.elapsedRealtime = elapsedRealtime;
         this.size = 0;
@@ -292,6 +455,7 @@
         }
     }
 
+    /** @hide */
     @UnsupportedAppUsage
     public NetworkStats(Parcel parcel) {
         elapsedRealtime = parcel.readLong();
@@ -312,7 +476,7 @@
     }
 
     @Override
-    public void writeToParcel(Parcel dest, int flags) {
+    public void writeToParcel(@NonNull Parcel dest, int flags) {
         dest.writeLong(elapsedRealtime);
         dest.writeInt(size);
         dest.writeInt(capacity);
@@ -330,19 +494,23 @@
         dest.writeLongArray(operations);
     }
 
+    /**
+     * @hide
+     */
     @Override
     public NetworkStats clone() {
         final NetworkStats clone = new NetworkStats(elapsedRealtime, size);
         NetworkStats.Entry entry = null;
         for (int i = 0; i < size; i++) {
             entry = getValues(i, entry);
-            clone.addValues(entry);
+            clone.insertEntry(entry);
         }
         return clone;
     }
 
     /**
      * Clear all data stored in this object.
+     * @hide
      */
     public void clear() {
         this.capacity = 0;
@@ -360,25 +528,28 @@
         this.operations = EmptyArray.LONG;
     }
 
+    /** @hide */
     @VisibleForTesting
-    public NetworkStats addIfaceValues(
+    public NetworkStats insertEntry(
             String iface, long rxBytes, long rxPackets, long txBytes, long txPackets) {
-        return addValues(
+        return insertEntry(
                 iface, UID_ALL, SET_DEFAULT, TAG_NONE, rxBytes, rxPackets, txBytes, txPackets, 0L);
     }
 
+    /** @hide */
     @VisibleForTesting
-    public NetworkStats addValues(String iface, int uid, int set, int tag, long rxBytes,
+    public NetworkStats insertEntry(String iface, int uid, int set, int tag, long rxBytes,
             long rxPackets, long txBytes, long txPackets, long operations) {
-        return addValues(new Entry(
+        return insertEntry(new Entry(
                 iface, uid, set, tag, rxBytes, rxPackets, txBytes, txPackets, operations));
     }
 
+    /** @hide */
     @VisibleForTesting
-    public NetworkStats addValues(String iface, int uid, int set, int tag, int metered, int roaming,
-            int defaultNetwork, long rxBytes, long rxPackets, long txBytes, long txPackets,
-            long operations) {
-        return addValues(new Entry(
+    public NetworkStats insertEntry(String iface, int uid, int set, int tag, int metered,
+            int roaming, int defaultNetwork, long rxBytes, long rxPackets, long txBytes,
+            long txPackets, long operations) {
+        return insertEntry(new Entry(
                 iface, uid, set, tag, metered, roaming, defaultNetwork, rxBytes, rxPackets,
                 txBytes, txPackets, operations));
     }
@@ -386,8 +557,9 @@
     /**
      * Add new stats entry, copying from given {@link Entry}. The {@link Entry}
      * object can be recycled across multiple calls.
+     * @hide
      */
-    public NetworkStats addValues(Entry entry) {
+    public NetworkStats insertEntry(Entry entry) {
         if (size >= capacity) {
             final int newLength = Math.max(size, 10) * 3 / 2;
             iface = Arrays.copyOf(iface, newLength);
@@ -428,6 +600,7 @@
 
     /**
      * Return specific stats entry.
+     * @hide
      */
     @UnsupportedAppUsage
     public Entry getValues(int i, Entry recycle) {
@@ -467,10 +640,12 @@
         operations[dest] = operations[src];
     }
 
+    /** @hide */
     public long getElapsedRealtime() {
         return elapsedRealtime;
     }
 
+    /** @hide */
     public void setElapsedRealtime(long time) {
         elapsedRealtime = time;
     }
@@ -478,21 +653,25 @@
     /**
      * Return age of this {@link NetworkStats} object with respect to
      * {@link SystemClock#elapsedRealtime()}.
+     * @hide
      */
     public long getElapsedRealtimeAge() {
         return SystemClock.elapsedRealtime() - elapsedRealtime;
     }
 
+    /** @hide */
     @UnsupportedAppUsage
     public int size() {
         return size;
     }
 
+    /** @hide */
     @VisibleForTesting
     public int internalSize() {
         return capacity;
     }
 
+    /** @hide */
     @Deprecated
     public NetworkStats combineValues(String iface, int uid, int tag, long rxBytes, long rxPackets,
             long txBytes, long txPackets, long operations) {
@@ -501,6 +680,7 @@
                 txPackets, operations);
     }
 
+    /** @hide */
     public NetworkStats combineValues(String iface, int uid, int set, int tag,
             long rxBytes, long rxPackets, long txBytes, long txPackets, long operations) {
         return combineValues(new Entry(
@@ -509,16 +689,20 @@
 
     /**
      * Combine given values with an existing row, or create a new row if
-     * {@link #findIndex(String, int, int, int, int)} is unable to find match. Can
-     * also be used to subtract values from existing rows.
+     * {@link #findIndex(String, int, int, int, int, int, int)} is unable to find match. Can
+     * also be used to subtract values from existing rows. This method mutates the referencing
+     * {@link NetworkStats} object.
+     *
+     * @param entry the {@link Entry} to combine.
+     * @return a reference to this mutated {@link NetworkStats} object.
+     * @hide
      */
-    @UnsupportedAppUsage
-    public NetworkStats combineValues(Entry entry) {
+    public @NonNull NetworkStats combineValues(@NonNull Entry entry) {
         final int i = findIndex(entry.iface, entry.uid, entry.set, entry.tag, entry.metered,
                 entry.roaming, entry.defaultNetwork);
         if (i == -1) {
             // only create new entry when positive contribution
-            addValues(entry);
+            insertEntry(entry);
         } else {
             rxBytes[i] += entry.rxBytes;
             rxPackets[i] += entry.rxPackets;
@@ -530,10 +714,33 @@
     }
 
     /**
-     * Combine all values from another {@link NetworkStats} into this object.
+     * Add given values with an existing row, or create a new row if
+     * {@link #findIndex(String, int, int, int, int, int, int)} is unable to find match. Can
+     * also be used to subtract values from existing rows.
+     *
+     * @param entry the {@link Entry} to add.
+     * @return a new constructed {@link NetworkStats} object that contains the result.
      */
-    @UnsupportedAppUsage
-    public void combineAllValues(NetworkStats another) {
+    public @NonNull NetworkStats addEntry(@NonNull Entry entry) {
+        return this.clone().combineValues(entry);
+    }
+
+    /**
+     * Add the given {@link NetworkStats} objects.
+     *
+     * @return the sum of two objects.
+     */
+    public @NonNull NetworkStats add(@NonNull NetworkStats another) {
+        final NetworkStats ret = this.clone();
+        ret.combineAllValues(another);
+        return ret;
+    }
+
+    /**
+     * Combine all values from another {@link NetworkStats} into this object.
+     * @hide
+     */
+    public void combineAllValues(@NonNull NetworkStats another) {
         NetworkStats.Entry entry = null;
         for (int i = 0; i < another.size; i++) {
             entry = another.getValues(i, entry);
@@ -543,6 +750,7 @@
 
     /**
      * Find first stats index that matches the requested parameters.
+     * @hide
      */
     public int findIndex(String iface, int uid, int set, int tag, int metered, int roaming,
             int defaultNetwork) {
@@ -560,6 +768,7 @@
     /**
      * Find first stats index that matches the requested parameters, starting
      * search around the hinted index as an optimization.
+     * @hide
      */
     @VisibleForTesting
     public int findIndexHinted(String iface, int uid, int set, int tag, int metered, int roaming,
@@ -589,6 +798,7 @@
      * Splice in {@link #operations} from the given {@link NetworkStats} based
      * on matching {@link #uid} and {@link #tag} rows. Ignores {@link #iface},
      * since operation counts are at data layer.
+     * @hide
      */
     public void spliceOperationsFrom(NetworkStats stats) {
         for (int i = 0; i < size; i++) {
@@ -604,6 +814,7 @@
 
     /**
      * Return list of unique interfaces known by this data structure.
+     * @hide
      */
     public String[] getUniqueIfaces() {
         final HashSet<String> ifaces = new HashSet<String>();
@@ -617,6 +828,7 @@
 
     /**
      * Return list of unique UIDs known by this data structure.
+     * @hide
      */
     @UnsupportedAppUsage
     public int[] getUniqueUids() {
@@ -636,6 +848,7 @@
     /**
      * Return total bytes represented by this snapshot object, usually used when
      * checking if a {@link #subtract(NetworkStats)} delta passes a threshold.
+     * @hide
      */
     @UnsupportedAppUsage
     public long getTotalBytes() {
@@ -645,6 +858,7 @@
 
     /**
      * Return total of all fields represented by this snapshot object.
+     * @hide
      */
     @UnsupportedAppUsage
     public Entry getTotal(Entry recycle) {
@@ -654,6 +868,7 @@
     /**
      * Return total of all fields represented by this snapshot object matching
      * the requested {@link #uid}.
+     * @hide
      */
     @UnsupportedAppUsage
     public Entry getTotal(Entry recycle, int limitUid) {
@@ -663,11 +878,13 @@
     /**
      * Return total of all fields represented by this snapshot object matching
      * the requested {@link #iface}.
+     * @hide
      */
     public Entry getTotal(Entry recycle, HashSet<String> limitIface) {
         return getTotal(recycle, limitIface, UID_ALL, false);
     }
 
+    /** @hide */
     @UnsupportedAppUsage
     public Entry getTotalIncludingTags(Entry recycle) {
         return getTotal(recycle, null, UID_ALL, true);
@@ -717,6 +934,7 @@
 
     /**
      * Fast path for battery stats.
+     * @hide
      */
     public long getTotalPackets() {
         long total = 0;
@@ -729,9 +947,12 @@
     /**
      * Subtract the given {@link NetworkStats}, effectively leaving the delta
      * between two snapshots in time. Assumes that statistics rows collect over
-     * time, and that none of them have disappeared.
+     * time, and that none of them have disappeared. This method does not mutate
+     * the referencing object.
+     *
+     * @return the delta between two objects.
      */
-    public NetworkStats subtract(NetworkStats right) {
+    public @NonNull NetworkStats subtract(@NonNull NetworkStats right) {
         return subtract(this, right, null, null);
     }
 
@@ -742,6 +963,7 @@
      * <p>
      * If counters have rolled backwards, they are clamped to {@code 0} and
      * reported to the given {@link NonMonotonicObserver}.
+     * @hide
      */
     public static <C> NetworkStats subtract(NetworkStats left, NetworkStats right,
             NonMonotonicObserver<C> observer, C cookie) {
@@ -759,6 +981,7 @@
      * If <var>recycle</var> is supplied, this NetworkStats object will be
      * reused (and returned) as the result if it is large enough to contain
      * the data.
+     * @hide
      */
     public static <C> NetworkStats subtract(NetworkStats left, NetworkStats right,
             NonMonotonicObserver<C> observer, C cookie, NetworkStats recycle) {
@@ -817,7 +1040,7 @@
                 entry.operations = Math.max(entry.operations, 0);
             }
 
-            result.addValues(entry);
+            result.insertEntry(entry);
         }
 
         return result;
@@ -847,6 +1070,7 @@
      * @param stackedTraffic Stats with traffic stacked on top of our ifaces. Will also be mutated.
      * @param stackedIfaces Mapping ipv6if -> ipv4if interface where traffic is counted on both.
      * @param useBpfStats True if eBPF is in use.
+     * @hide
      */
     public static void apply464xlatAdjustments(NetworkStats baseTraffic,
             NetworkStats stackedTraffic, Map<String, String> stackedIfaces, boolean useBpfStats) {
@@ -899,6 +1123,7 @@
      * {@link #apply464xlatAdjustments(NetworkStats, NetworkStats, Map)} with {@code this} as
      * base and stacked traffic.
      * @param stackedIfaces Mapping ipv6if -> ipv4if interface where traffic is counted on both.
+     * @hide
      */
     public void apply464xlatAdjustments(Map<String, String> stackedIfaces, boolean useBpfStats) {
         apply464xlatAdjustments(this, this, stackedIfaces, useBpfStats);
@@ -907,6 +1132,7 @@
     /**
      * Return total statistics grouped by {@link #iface}; doesn't mutate the
      * original structure.
+     * @hide
      */
     public NetworkStats groupedByIface() {
         final NetworkStats stats = new NetworkStats(elapsedRealtime, 10);
@@ -938,6 +1164,7 @@
     /**
      * Return total statistics grouped by {@link #uid}; doesn't mutate the
      * original structure.
+     * @hide
      */
     public NetworkStats groupedByUid() {
         final NetworkStats stats = new NetworkStats(elapsedRealtime, 10);
@@ -968,17 +1195,24 @@
 
     /**
      * Remove all rows that match one of specified UIDs.
+     * This mutates the original structure in place.
+     * @hide
      */
     public void removeUids(int[] uids) {
-        int nextOutputEntry = 0;
-        for (int i = 0; i < size; i++) {
-            if (!ArrayUtils.contains(uids, uid[i])) {
-                maybeCopyEntry(nextOutputEntry, i);
-                nextOutputEntry++;
-            }
-        }
+        filter(e -> !ArrayUtils.contains(uids, e.uid));
+    }
 
-        size = nextOutputEntry;
+    /**
+     * Remove all rows that match one of specified UIDs.
+     * @return the result object.
+     * @hide
+     */
+    @NonNull
+    public NetworkStats removeEmptyEntries() {
+        final NetworkStats ret = this.clone();
+        ret.filter(e -> e.rxBytes != 0 || e.rxPackets != 0 || e.txBytes != 0 || e.txPackets != 0
+                || e.operations != 0);
+        return ret;
     }
 
     /**
@@ -989,6 +1223,7 @@
      * @param limitUid UID to filter for, or {@link #UID_ALL}.
      * @param limitIfaces Interfaces to filter for, or {@link #INTERFACES_ALL}.
      * @param limitTag Tag to filter for, or {@link #TAG_ALL}.
+     * @hide
      */
     public void filter(int limitUid, String[] limitIfaces, int limitTag) {
         if (limitUid == UID_ALL && limitTag == TAG_ALL && limitIfaces == INTERFACES_ALL) {
@@ -1004,6 +1239,7 @@
      * Only keep entries with {@link #set} value less than {@link #SET_DEBUG_START}.
      *
      * <p>This mutates the original structure in place.
+     * @hide
      */
     public void filterDebugEntries() {
         filter(e -> e.set < SET_DEBUG_START);
@@ -1024,6 +1260,7 @@
         size = nextOutputEntry;
     }
 
+    /** @hide */
     public void dump(String prefix, PrintWriter pw) {
         pw.print(prefix);
         pw.print("NetworkStats: elapsedRealtime="); pw.println(elapsedRealtime);
@@ -1047,6 +1284,7 @@
 
     /**
      * Return text description of {@link #set} value.
+     * @hide
      */
     public static String setToString(int set) {
         switch (set) {
@@ -1067,6 +1305,7 @@
 
     /**
      * Return text description of {@link #set} value.
+     * @hide
      */
     public static String setToCheckinString(int set) {
         switch (set) {
@@ -1087,6 +1326,7 @@
 
     /**
      * @return true if the querySet matches the dataSet.
+     * @hide
      */
     public static boolean setMatches(int querySet, int dataSet) {
         if (querySet == dataSet) {
@@ -1098,6 +1338,7 @@
 
     /**
      * Return text description of {@link #tag} value.
+     * @hide
      */
     public static String tagToString(int tag) {
         return "0x" + Integer.toHexString(tag);
@@ -1105,6 +1346,7 @@
 
     /**
      * Return text description of {@link #metered} value.
+     * @hide
      */
     public static String meteredToString(int metered) {
         switch (metered) {
@@ -1121,6 +1363,7 @@
 
     /**
      * Return text description of {@link #roaming} value.
+     * @hide
      */
     public static String roamingToString(int roaming) {
         switch (roaming) {
@@ -1137,6 +1380,7 @@
 
     /**
      * Return text description of {@link #defaultNetwork} value.
+     * @hide
      */
     public static String defaultNetworkToString(int defaultNetwork) {
         switch (defaultNetwork) {
@@ -1151,6 +1395,7 @@
         }
     }
 
+    /** @hide */
     @Override
     public String toString() {
         final CharArrayWriter writer = new CharArrayWriter();
@@ -1163,8 +1408,7 @@
         return 0;
     }
 
-    @UnsupportedAppUsage
-    public static final @android.annotation.NonNull Creator<NetworkStats> CREATOR = new Creator<NetworkStats>() {
+    public static final @NonNull Creator<NetworkStats> CREATOR = new Creator<NetworkStats>() {
         @Override
         public NetworkStats createFromParcel(Parcel in) {
             return new NetworkStats(in);
@@ -1176,6 +1420,7 @@
         }
     };
 
+    /** @hide */
     public interface NonMonotonicObserver<C> {
         public void foundNonMonotonic(
                 NetworkStats left, int leftIndex, NetworkStats right, int rightIndex, C cookie);
@@ -1195,6 +1440,7 @@
      * @param tunUid uid of the VPN application
      * @param tunIface iface of the vpn tunnel
      * @param underlyingIfaces underlying network ifaces used by the VPN application
+     * @hide
      */
     public void migrateTun(int tunUid, @NonNull String tunIface,
             @NonNull String[] underlyingIfaces) {
diff --git a/core/java/android/net/NetworkStatsHistory.java b/core/java/android/net/NetworkStatsHistory.java
index f61260e..c82c288 100644
--- a/core/java/android/net/NetworkStatsHistory.java
+++ b/core/java/android/net/NetworkStatsHistory.java
@@ -30,7 +30,7 @@
 
 import static com.android.internal.util.ArrayUtils.total;
 
-import android.annotation.UnsupportedAppUsage;
+import android.compat.annotation.UnsupportedAppUsage;
 import android.os.Parcel;
 import android.os.Parcelable;
 import android.service.NetworkStatsHistoryBucketProto;
@@ -548,32 +548,32 @@
         final int startIndex = getIndexAfter(end);
         for (int i = startIndex; i >= 0; i--) {
             final long curStart = bucketStart[i];
-            final long curEnd = curStart + bucketDuration;
+            long curEnd = curStart + bucketDuration;
 
             // bucket is older than request; we're finished
             if (curEnd <= start) break;
             // bucket is newer than request; keep looking
             if (curStart >= end) continue;
 
-            // include full value for active buckets, otherwise only fractional
-            final boolean activeBucket = curStart < now && curEnd > now;
-            final long overlap;
-            if (activeBucket) {
-                overlap = bucketDuration;
-            } else {
-                final long overlapEnd = curEnd < end ? curEnd : end;
-                final long overlapStart = curStart > start ? curStart : start;
-                overlap = overlapEnd - overlapStart;
-            }
+            // the active bucket is shorter then a normal completed bucket
+            if (curEnd > now) curEnd = now;
+            // usually this is simply bucketDuration
+            final long bucketSpan = curEnd - curStart;
+            // prevent division by zero
+            if (bucketSpan <= 0) continue;
+
+            final long overlapEnd = curEnd < end ? curEnd : end;
+            final long overlapStart = curStart > start ? curStart : start;
+            final long overlap = overlapEnd - overlapStart;
             if (overlap <= 0) continue;
 
             // integer math each time is faster than floating point
-            if (activeTime != null) entry.activeTime += activeTime[i] * overlap / bucketDuration;
-            if (rxBytes != null) entry.rxBytes += rxBytes[i] * overlap / bucketDuration;
-            if (rxPackets != null) entry.rxPackets += rxPackets[i] * overlap / bucketDuration;
-            if (txBytes != null) entry.txBytes += txBytes[i] * overlap / bucketDuration;
-            if (txPackets != null) entry.txPackets += txPackets[i] * overlap / bucketDuration;
-            if (operations != null) entry.operations += operations[i] * overlap / bucketDuration;
+            if (activeTime != null) entry.activeTime += activeTime[i] * overlap / bucketSpan;
+            if (rxBytes != null) entry.rxBytes += rxBytes[i] * overlap / bucketSpan;
+            if (rxPackets != null) entry.rxPackets += rxPackets[i] * overlap / bucketSpan;
+            if (txBytes != null) entry.txBytes += txBytes[i] * overlap / bucketSpan;
+            if (txPackets != null) entry.txPackets += txPackets[i] * overlap / bucketSpan;
+            if (operations != null) entry.operations += operations[i] * overlap / bucketSpan;
         }
         return entry;
     }
diff --git a/core/java/android/net/NetworkTemplate.java b/core/java/android/net/NetworkTemplate.java
index ae421a4..cb9463a 100644
--- a/core/java/android/net/NetworkTemplate.java
+++ b/core/java/android/net/NetworkTemplate.java
@@ -32,11 +32,15 @@
 import static android.net.NetworkStats.ROAMING_ALL;
 import static android.net.NetworkStats.ROAMING_NO;
 import static android.net.NetworkStats.ROAMING_YES;
-import static android.net.wifi.WifiInfo.removeDoubleQuotes;
+import static android.net.wifi.WifiInfo.sanitizeSsid;
 
-import android.annotation.UnsupportedAppUsage;
+import android.annotation.Nullable;
+import android.compat.annotation.UnsupportedAppUsage;
 import android.os.Parcel;
 import android.os.Parcelable;
+import android.telephony.Annotation.NetworkType;
+import android.telephony.TelephonyManager;
+import android.text.TextUtils;
 import android.util.BackupUtils;
 import android.util.Log;
 
@@ -48,6 +52,7 @@
 import java.io.DataOutputStream;
 import java.io.IOException;
 import java.util.Arrays;
+import java.util.List;
 import java.util.Objects;
 
 /**
@@ -72,6 +77,14 @@
     public static final int MATCH_BLUETOOTH = 8;
     public static final int MATCH_PROXY = 9;
 
+    /**
+     * Include all network types when filtering. This is meant to merge in with the
+     * {@code TelephonyManager.NETWORK_TYPE_*} constants, and thus needs to stay in sync.
+     *
+     * @hide
+     */
+    public static final int NETWORK_TYPE_ALL = -1;
+
     private static boolean isKnownMatchRule(final int rule) {
         switch (rule) {
             case MATCH_MOBILE:
@@ -116,7 +129,22 @@
     }
 
     /**
-     * Template to match {@link ConnectivityManager#TYPE_MOBILE} networks,
+     * Template to match cellular networks with the given IMSI and {@code ratType}.
+     * Use {@link #NETWORK_TYPE_ALL} to include all network types when filtering.
+     * See {@code TelephonyManager.NETWORK_TYPE_*}.
+     */
+    public static NetworkTemplate buildTemplateMobileWithRatType(@Nullable String subscriberId,
+            @NetworkType int ratType) {
+        if (TextUtils.isEmpty(subscriberId)) {
+            return new NetworkTemplate(MATCH_MOBILE_WILDCARD, null, null, null,
+                    METERED_ALL, ROAMING_ALL, DEFAULT_NETWORK_ALL, ratType);
+        }
+        return new NetworkTemplate(MATCH_MOBILE, subscriberId, new String[]{subscriberId}, null,
+                METERED_ALL, ROAMING_ALL, DEFAULT_NETWORK_ALL, ratType);
+    }
+
+    /**
+     * Template to match metered {@link ConnectivityManager#TYPE_MOBILE} networks,
      * regardless of IMSI.
      */
     @UnsupportedAppUsage
@@ -125,7 +153,7 @@
     }
 
     /**
-     * Template to match all {@link ConnectivityManager#TYPE_WIFI} networks,
+     * Template to match all metered {@link ConnectivityManager#TYPE_WIFI} networks,
      * regardless of SSID.
      */
     @UnsupportedAppUsage
@@ -191,6 +219,7 @@
     private final int mMetered;
     private final int mRoaming;
     private final int mDefaultNetwork;
+    private final int mSubType;
 
     @UnsupportedAppUsage
     public NetworkTemplate(int matchRule, String subscriberId, String networkId) {
@@ -200,11 +229,11 @@
     public NetworkTemplate(int matchRule, String subscriberId, String[] matchSubscriberIds,
             String networkId) {
         this(matchRule, subscriberId, matchSubscriberIds, networkId, METERED_ALL, ROAMING_ALL,
-                DEFAULT_NETWORK_ALL);
+                DEFAULT_NETWORK_ALL, NETWORK_TYPE_ALL);
     }
 
     public NetworkTemplate(int matchRule, String subscriberId, String[] matchSubscriberIds,
-            String networkId, int metered, int roaming, int defaultNetwork) {
+            String networkId, int metered, int roaming, int defaultNetwork, int subType) {
         mMatchRule = matchRule;
         mSubscriberId = subscriberId;
         mMatchSubscriberIds = matchSubscriberIds;
@@ -212,6 +241,7 @@
         mMetered = metered;
         mRoaming = roaming;
         mDefaultNetwork = defaultNetwork;
+        mSubType = subType;
 
         if (!isKnownMatchRule(matchRule)) {
             Log.e(TAG, "Unknown network template rule " + matchRule
@@ -227,6 +257,7 @@
         mMetered = in.readInt();
         mRoaming = in.readInt();
         mDefaultNetwork = in.readInt();
+        mSubType = in.readInt();
     }
 
     @Override
@@ -238,6 +269,7 @@
         dest.writeInt(mMetered);
         dest.writeInt(mRoaming);
         dest.writeInt(mDefaultNetwork);
+        dest.writeInt(mSubType);
     }
 
     @Override
@@ -270,13 +302,16 @@
             builder.append(", defaultNetwork=").append(NetworkStats.defaultNetworkToString(
                     mDefaultNetwork));
         }
+        if (mSubType != NETWORK_TYPE_ALL) {
+            builder.append(", subType=").append(mSubType);
+        }
         return builder.toString();
     }
 
     @Override
     public int hashCode() {
         return Objects.hash(mMatchRule, mSubscriberId, mNetworkId, mMetered, mRoaming,
-                mDefaultNetwork);
+                mDefaultNetwork, mSubType);
     }
 
     @Override
@@ -288,7 +323,8 @@
                     && Objects.equals(mNetworkId, other.mNetworkId)
                     && mMetered == other.mMetered
                     && mRoaming == other.mRoaming
-                    && mDefaultNetwork == other.mDefaultNetwork;
+                    && mDefaultNetwork == other.mDefaultNetwork
+                    && mSubType == other.mSubType;
         }
         return false;
     }
@@ -375,6 +411,11 @@
             || (mDefaultNetwork == DEFAULT_NETWORK_NO && !ident.mDefaultNetwork);
     }
 
+    private boolean matchesCollapsedRatType(NetworkIdentity ident) {
+        return mSubType == NETWORK_TYPE_ALL
+                || getCollapsedRatType(mSubType) == getCollapsedRatType(ident.mSubType);
+    }
+
     public boolean matchesSubscriberId(String subscriberId) {
         return ArrayUtils.contains(mMatchSubscriberIds, subscriberId);
     }
@@ -387,9 +428,52 @@
             // TODO: consider matching against WiMAX subscriber identity
             return true;
         } else {
+            // Only metered mobile network would be matched regardless of metered filter.
+            // This is used to exclude non-metered APNs, e.g. IMS. See ag/908650.
+            // TODO: Respect metered filter and remove mMetered condition.
             return (sForceAllNetworkTypes || (ident.mType == TYPE_MOBILE && ident.mMetered))
                     && !ArrayUtils.isEmpty(mMatchSubscriberIds)
-                    && ArrayUtils.contains(mMatchSubscriberIds, ident.mSubscriberId);
+                    && ArrayUtils.contains(mMatchSubscriberIds, ident.mSubscriberId)
+                    && matchesCollapsedRatType(ident);
+        }
+    }
+
+    /**
+     * Get a Radio Access Technology(RAT) type that is representative of a group of RAT types.
+     * The mapping is corresponding to {@code TelephonyManager#NETWORK_CLASS_BIT_MASK_*}.
+     *
+     * @param ratType An integer defined in {@code TelephonyManager#NETWORK_TYPE_*}.
+     */
+    // TODO: 1. Consider move this to TelephonyManager if used by other modules.
+    //       2. Consider make this configurable.
+    //       3. Use TelephonyManager APIs when available.
+    public static int getCollapsedRatType(int ratType) {
+        switch (ratType) {
+            case TelephonyManager.NETWORK_TYPE_GPRS:
+            case TelephonyManager.NETWORK_TYPE_GSM:
+            case TelephonyManager.NETWORK_TYPE_EDGE:
+            case TelephonyManager.NETWORK_TYPE_IDEN:
+            case TelephonyManager.NETWORK_TYPE_CDMA:
+            case TelephonyManager.NETWORK_TYPE_1xRTT:
+                return TelephonyManager.NETWORK_TYPE_GSM;
+            case TelephonyManager.NETWORK_TYPE_EVDO_0:
+            case TelephonyManager.NETWORK_TYPE_EVDO_A:
+            case TelephonyManager.NETWORK_TYPE_EVDO_B:
+            case TelephonyManager.NETWORK_TYPE_EHRPD:
+            case TelephonyManager.NETWORK_TYPE_UMTS:
+            case TelephonyManager.NETWORK_TYPE_HSDPA:
+            case TelephonyManager.NETWORK_TYPE_HSUPA:
+            case TelephonyManager.NETWORK_TYPE_HSPA:
+            case TelephonyManager.NETWORK_TYPE_HSPAP:
+            case TelephonyManager.NETWORK_TYPE_TD_SCDMA:
+                return TelephonyManager.NETWORK_TYPE_UMTS;
+            case TelephonyManager.NETWORK_TYPE_LTE:
+            case TelephonyManager.NETWORK_TYPE_IWLAN:
+                return TelephonyManager.NETWORK_TYPE_LTE;
+            case TelephonyManager.NETWORK_TYPE_NR:
+                return TelephonyManager.NETWORK_TYPE_NR;
+            default:
+                return TelephonyManager.NETWORK_TYPE_UNKNOWN;
         }
     }
 
@@ -400,7 +484,7 @@
         switch (ident.mType) {
             case TYPE_WIFI:
                 return Objects.equals(
-                        removeDoubleQuotes(mNetworkId), removeDoubleQuotes(ident.mNetworkId));
+                        sanitizeSsid(mNetworkId), sanitizeSsid(ident.mNetworkId));
             default:
                 return false;
         }
@@ -420,7 +504,8 @@
         if (ident.mType == TYPE_WIMAX) {
             return true;
         } else {
-            return sForceAllNetworkTypes || (ident.mType == TYPE_MOBILE && ident.mMetered);
+            return (sForceAllNetworkTypes || (ident.mType == TYPE_MOBILE && ident.mMetered))
+                    && matchesCollapsedRatType(ident);
         }
     }
 
@@ -481,17 +566,39 @@
      * For example, given an incoming template matching B, and the currently
      * active merge set [A,B], we'd return a new template that primarily matches
      * A, but also matches B.
+     * TODO: remove and use {@link #normalize(NetworkTemplate, List)}.
      */
     @UnsupportedAppUsage
     public static NetworkTemplate normalize(NetworkTemplate template, String[] merged) {
-        if (template.isMatchRuleMobile() && ArrayUtils.contains(merged, template.mSubscriberId)) {
-            // Requested template subscriber is part of the merge group; return
-            // a template that matches all merged subscribers.
-            return new NetworkTemplate(template.mMatchRule, merged[0], merged,
-                    template.mNetworkId);
-        } else {
-            return template;
+        return normalize(template, Arrays.<String[]>asList(merged));
+    }
+
+    /**
+     * Examine the given template and normalize if it refers to a "merged"
+     * mobile subscriber. We pick the "lowest" merged subscriber as the primary
+     * for key purposes, and expand the template to match all other merged
+     * subscribers.
+     *
+     * There can be multiple merged subscriberIds for multi-SIM devices.
+     *
+     * <p>
+     * For example, given an incoming template matching B, and the currently
+     * active merge set [A,B], we'd return a new template that primarily matches
+     * A, but also matches B.
+     */
+    public static NetworkTemplate normalize(NetworkTemplate template, List<String[]> mergedList) {
+        if (!template.isMatchRuleMobile()) return template;
+
+        for (String[] merged : mergedList) {
+            if (ArrayUtils.contains(merged, template.mSubscriberId)) {
+                // Requested template subscriber is part of the merge group; return
+                // a template that matches all merged subscribers.
+                return new NetworkTemplate(template.mMatchRule, merged[0], merged,
+                        template.mNetworkId);
+            }
         }
+
+        return template;
     }
 
     @UnsupportedAppUsage
diff --git a/core/java/android/net/TrafficStats.java b/core/java/android/net/TrafficStats.java
index 1c6a484..8108cf0 100644
--- a/core/java/android/net/TrafficStats.java
+++ b/core/java/android/net/TrafficStats.java
@@ -16,13 +16,14 @@
 
 package android.net;
 
+import android.annotation.NonNull;
 import android.annotation.SuppressLint;
 import android.annotation.SystemApi;
 import android.annotation.TestApi;
-import android.annotation.UnsupportedAppUsage;
 import android.app.DownloadManager;
 import android.app.backup.BackupManager;
 import android.app.usage.NetworkStatsManager;
+import android.compat.annotation.UnsupportedAppUsage;
 import android.content.Context;
 import android.media.MediaPlayer;
 import android.os.Build;
@@ -88,7 +89,7 @@
      *
      * @hide
      */
-    public static final int UID_TETHERING = -5;
+    public static final int UID_TETHERING = NetworkStats.UID_TETHERING;
 
     /**
      * Tag values in this range are reserved for the network stack. The network stack is
@@ -595,8 +596,15 @@
         return total;
     }
 
-    /** {@hide} */
-    public static long getTxPackets(String iface) {
+    /**
+     * Return the number of packets transmitted on the specified interface since
+     * device boot. Statistics are measured at the network layer, so both TCP and
+     * UDP usage are included.
+     *
+     * @param iface The name of the interface.
+     * @return The number of transmitted packets.
+     */
+    public static long getTxPackets(@NonNull String iface) {
         try {
             return getStatsService().getIfaceStats(iface, TYPE_TX_PACKETS);
         } catch (RemoteException e) {
@@ -604,8 +612,15 @@
         }
     }
 
-    /** {@hide} */
-    public static long getRxPackets(String iface) {
+    /**
+     * Return the number of packets received on the specified interface since
+     * device boot. Statistics are measured at the network layer, so both TCP
+     * and UDP usage are included.
+     *
+     * @param iface The name of the interface.
+     * @return The number of received packets.
+     */
+    public static long getRxPackets(@NonNull String iface) {
         try {
             return getStatsService().getIfaceStats(iface, TYPE_RX_PACKETS);
         } catch (RemoteException e) {
diff --git a/core/java/android/net/netstats/provider/INetworkStatsProvider.aidl b/core/java/android/net/netstats/provider/INetworkStatsProvider.aidl
new file mode 100644
index 0000000..4078b24
--- /dev/null
+++ b/core/java/android/net/netstats/provider/INetworkStatsProvider.aidl
@@ -0,0 +1,28 @@
+/*
+ * Copyright (C) 2020 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.netstats.provider;
+
+/**
+ * Interface for NetworkStatsService to query network statistics and set data limits.
+ *
+ * @hide
+ */
+oneway interface INetworkStatsProvider {
+    void onRequestStatsUpdate(int token);
+    void onSetLimit(String iface, long quotaBytes);
+    void onSetAlert(long quotaBytes);
+}
diff --git a/core/java/android/net/netstats/provider/INetworkStatsProviderCallback.aidl b/core/java/android/net/netstats/provider/INetworkStatsProviderCallback.aidl
new file mode 100644
index 0000000..bd336dd
--- /dev/null
+++ b/core/java/android/net/netstats/provider/INetworkStatsProviderCallback.aidl
@@ -0,0 +1,31 @@
+/*
+ * Copyright (C) 2020 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.netstats.provider;
+
+import android.net.NetworkStats;
+
+/**
+ * Interface for implementor of {@link INetworkStatsProviderCallback} to push events
+ * such as network statistics update or notify limit reached.
+ * @hide
+ */
+oneway interface INetworkStatsProviderCallback {
+    void notifyStatsUpdated(int token, in NetworkStats ifaceStats, in NetworkStats uidStats);
+    void notifyAlertReached();
+    void notifyLimitReached();
+    void unregister();
+}
diff --git a/core/java/android/net/netstats/provider/NetworkStatsProvider.java b/core/java/android/net/netstats/provider/NetworkStatsProvider.java
new file mode 100644
index 0000000..7639d22
--- /dev/null
+++ b/core/java/android/net/netstats/provider/NetworkStatsProvider.java
@@ -0,0 +1,195 @@
+/*
+ * Copyright (C) 2020 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.netstats.provider;
+
+import android.annotation.NonNull;
+import android.annotation.Nullable;
+import android.annotation.SystemApi;
+import android.net.NetworkStats;
+import android.os.RemoteException;
+
+/**
+ * A base class that allows external modules to implement a custom network statistics provider.
+ * @hide
+ */
+@SystemApi
+public abstract class NetworkStatsProvider {
+    /**
+     * A value used by {@link #onSetLimit} and {@link #onSetAlert} indicates there is no limit.
+     */
+    public static final int QUOTA_UNLIMITED = -1;
+
+    @NonNull private final INetworkStatsProvider mProviderBinder =
+            new INetworkStatsProvider.Stub() {
+
+        @Override
+        public void onRequestStatsUpdate(int token) {
+            NetworkStatsProvider.this.onRequestStatsUpdate(token);
+        }
+
+        @Override
+        public void onSetLimit(String iface, long quotaBytes) {
+            NetworkStatsProvider.this.onSetLimit(iface, quotaBytes);
+        }
+
+        @Override
+        public void onSetAlert(long quotaBytes) {
+            NetworkStatsProvider.this.onSetAlert(quotaBytes);
+        }
+    };
+
+    // The binder given by the service when successfully registering. Only null before registering,
+    // never null once non-null.
+    @Nullable
+    private INetworkStatsProviderCallback mProviderCbBinder;
+
+    /**
+     * Return the binder invoked by the service and redirect function calls to the overridden
+     * methods.
+     * @hide
+     */
+    @NonNull
+    public INetworkStatsProvider getProviderBinder() {
+        return mProviderBinder;
+    }
+
+    /**
+     * Store the binder that was returned by the service when successfully registering. Note that
+     * the provider cannot be re-registered. Hence this method can only be called once per provider.
+     *
+     * @hide
+     */
+    public void setProviderCallbackBinder(@NonNull INetworkStatsProviderCallback binder) {
+        if (mProviderCbBinder != null) {
+            throw new IllegalArgumentException("provider is already registered");
+        }
+        mProviderCbBinder = binder;
+    }
+
+    /**
+     * Get the binder that was returned by the service when successfully registering. Or null if the
+     * provider was never registered.
+     *
+     * @hide
+     */
+    @Nullable
+    public INetworkStatsProviderCallback getProviderCallbackBinder() {
+        return mProviderCbBinder;
+    }
+
+    /**
+     * Get the binder that was returned by the service when successfully registering. Throw an
+     * {@link IllegalStateException} if the provider is not registered.
+     *
+     * @hide
+     */
+    @NonNull
+    public INetworkStatsProviderCallback getProviderCallbackBinderOrThrow() {
+        if (mProviderCbBinder == null) {
+            throw new IllegalStateException("the provider is not registered");
+        }
+        return mProviderCbBinder;
+    }
+
+    /**
+     * Notify the system of new network statistics.
+     *
+     * Send the network statistics recorded since the last call to {@link #notifyStatsUpdated}. Must
+     * be called as soon as possible after {@link NetworkStatsProvider#onRequestStatsUpdate(int)}
+     * being called. Responding later increases the probability stats will be dropped. The
+     * provider can also call this whenever it wants to reports new stats for any reason.
+     * Note that the system will not necessarily immediately propagate the statistics to
+     * reflect the update.
+     *
+     * @param token the token under which these stats were gathered. Providers can call this method
+     *              with the current token as often as they want, until the token changes.
+     *              {@see NetworkStatsProvider#onRequestStatsUpdate()}
+     * @param ifaceStats the {@link NetworkStats} per interface to be reported.
+     *                   The provider should not include any traffic that is already counted by
+     *                   kernel interface counters.
+     * @param uidStats the same stats as above, but counts {@link NetworkStats}
+     *                 per uid.
+     */
+    public void notifyStatsUpdated(int token, @NonNull NetworkStats ifaceStats,
+            @NonNull NetworkStats uidStats) {
+        try {
+            getProviderCallbackBinderOrThrow().notifyStatsUpdated(token, ifaceStats, uidStats);
+        } catch (RemoteException e) {
+            e.rethrowAsRuntimeException();
+        }
+    }
+
+    /**
+     * Notify system that the quota set by {@code onSetAlert} has been reached.
+     */
+    public void notifyAlertReached() {
+        try {
+            getProviderCallbackBinderOrThrow().notifyAlertReached();
+        } catch (RemoteException e) {
+            e.rethrowAsRuntimeException();
+        }
+    }
+
+    /**
+     * Notify system that the quota set by {@code onSetLimit} has been reached.
+     */
+    public void notifyLimitReached() {
+        try {
+            getProviderCallbackBinderOrThrow().notifyLimitReached();
+        } catch (RemoteException e) {
+            e.rethrowAsRuntimeException();
+        }
+    }
+
+    /**
+     * Called by {@code NetworkStatsService} when it requires to know updated stats.
+     * The provider MUST respond by calling {@link #notifyStatsUpdated} as soon as possible.
+     * Responding later increases the probability stats will be dropped. Memory allowing, the
+     * system will try to take stats into account up to one minute after calling
+     * {@link #onRequestStatsUpdate}.
+     *
+     * @param token a positive number identifying the new state of the system under which
+     *              {@link NetworkStats} have to be gathered from now on. When this is called,
+     *              custom implementations of providers MUST tally and report the latest stats with
+     *              the previous token, under which stats were being gathered so far.
+     */
+    public abstract void onRequestStatsUpdate(int token);
+
+    /**
+     * Called by {@code NetworkStatsService} when setting the interface quota for the specified
+     * upstream interface. When this is called, the custom implementation should block all egress
+     * packets on the {@code iface} associated with the provider when {@code quotaBytes} bytes have
+     * been reached, and MUST respond to it by calling
+     * {@link NetworkStatsProvider#notifyLimitReached()}.
+     *
+     * @param iface the interface requiring the operation.
+     * @param quotaBytes the quota defined as the number of bytes, starting from zero and counting
+     *                   from now. A value of {@link #QUOTA_UNLIMITED} indicates there is no limit.
+     */
+    public abstract void onSetLimit(@NonNull String iface, long quotaBytes);
+
+    /**
+     * Called by {@code NetworkStatsService} when setting the alert bytes. Custom implementations
+     * MUST call {@link NetworkStatsProvider#notifyAlertReached()} when {@code quotaBytes} bytes
+     * have been reached. Unlike {@link #onSetLimit(String, long)}, the custom implementation should
+     * not block all egress packets.
+     *
+     * @param quotaBytes the quota defined as the number of bytes, starting from zero and counting
+     *                   from now. A value of {@link #QUOTA_UNLIMITED} indicates there is no alert.
+     */
+    public abstract void onSetAlert(long quotaBytes);
+}
diff --git a/core/java/android/net/nsd/NsdManager.java b/core/java/android/net/nsd/NsdManager.java
index 535bf67..64f20b8 100644
--- a/core/java/android/net/nsd/NsdManager.java
+++ b/core/java/android/net/nsd/NsdManager.java
@@ -49,8 +49,8 @@
  * limited to a local network over Multicast DNS. DNS service discovery is described at
  * http://files.dns-sd.org/draft-cheshire-dnsext-dns-sd.txt
  *
- * <p> The API is asynchronous and responses to requests from an application are on listener
- * callbacks on a seperate internal thread.
+ * <p> The API is asynchronous, and responses to requests from an application are on listener
+ * callbacks on a separate internal thread.
  *
  * <p> There are three main operations the API supports - registration, discovery and resolution.
  * <pre>
diff --git a/core/java/android/net/nsd/NsdServiceInfo.java b/core/java/android/net/nsd/NsdServiceInfo.java
index 459b140..0946499 100644
--- a/core/java/android/net/nsd/NsdServiceInfo.java
+++ b/core/java/android/net/nsd/NsdServiceInfo.java
@@ -17,13 +17,13 @@
 package android.net.nsd;
 
 import android.annotation.NonNull;
-import android.annotation.UnsupportedAppUsage;
-import android.os.Parcelable;
+import android.compat.annotation.UnsupportedAppUsage;
 import android.os.Parcel;
+import android.os.Parcelable;
 import android.text.TextUtils;
+import android.util.ArrayMap;
 import android.util.Base64;
 import android.util.Log;
-import android.util.ArrayMap;
 
 import java.io.UnsupportedEncodingException;
 import java.net.InetAddress;
diff --git a/packages/Tethering/src/android/net/util/TetheringMessageBase.java b/packages/Tethering/src/android/net/util/TetheringMessageBase.java
new file mode 100644
index 0000000..1b763ce
--- /dev/null
+++ b/packages/Tethering/src/android/net/util/TetheringMessageBase.java
@@ -0,0 +1,25 @@
+/*
+ * Copyright (C) 2020 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.util;
+
+/**
+ * This class defines Message.what base addresses for various state machine.
+ */
+public class TetheringMessageBase {
+    public static final int BASE_MASTER   = 0;
+    public static final int BASE_IPSERVER = 100;
+
+}
diff --git a/services/core/java/com/android/server/IpSecService.java b/services/core/java/com/android/server/IpSecService.java
index 3964b39..6402e07 100644
--- a/services/core/java/com/android/server/IpSecService.java
+++ b/services/core/java/com/android/server/IpSecService.java
@@ -25,8 +25,6 @@
 import static android.system.OsConstants.IPPROTO_UDP;
 import static android.system.OsConstants.SOCK_DGRAM;
 
-import static com.android.internal.util.Preconditions.checkNotNull;
-
 import android.annotation.NonNull;
 import android.app.AppOpsManager;
 import android.content.Context;
@@ -48,6 +46,7 @@
 import android.net.util.NetdService;
 import android.os.Binder;
 import android.os.IBinder;
+import android.os.INetworkManagementService;
 import android.os.ParcelFileDescriptor;
 import android.os.RemoteException;
 import android.os.ServiceSpecificException;
@@ -76,6 +75,7 @@
 import java.net.UnknownHostException;
 import java.util.ArrayList;
 import java.util.List;
+import java.util.Objects;
 
 /**
  * A service to manage multiple clients that want to access the IpSec API. The service is
@@ -115,6 +115,9 @@
     /* Binder context for this service */
     private final Context mContext;
 
+    /* NetworkManager instance */
+    private final INetworkManagementService mNetworkManager;
+
     /**
      * The next non-repeating global ID for tracking resources between users, this service, and
      * kernel data structures. Accessing this variable is not thread safe, so it is only read or
@@ -360,10 +363,14 @@
     @VisibleForTesting
     static final class UserRecord {
         /* Maximum number of each type of resource that a single UID may possess */
-        public static final int MAX_NUM_TUNNEL_INTERFACES = 2;
-        public static final int MAX_NUM_ENCAP_SOCKETS = 2;
-        public static final int MAX_NUM_TRANSFORMS = 4;
-        public static final int MAX_NUM_SPIS = 8;
+
+        // Up to 4 active VPNs/IWLAN with potential soft handover.
+        public static final int MAX_NUM_TUNNEL_INTERFACES = 8;
+        public static final int MAX_NUM_ENCAP_SOCKETS = 16;
+
+        // SPIs and Transforms are both cheap, and are 1:1 correlated.
+        public static final int MAX_NUM_TRANSFORMS = 64;
+        public static final int MAX_NUM_SPIS = 64;
 
         /**
          * Store each of the OwnedResource types in an (thinly wrapped) sparse array for indexing
@@ -566,7 +573,7 @@
         }
 
         void put(int key, RefcountedResource<T> obj) {
-            checkNotNull(obj, "Null resources cannot be added");
+            Objects.requireNonNull(obj, "Null resources cannot be added");
             mArray.put(key, obj);
         }
 
@@ -989,12 +996,13 @@
      *
      * @param context Binder context for this service
      */
-    private IpSecService(Context context) {
-        this(context, IpSecServiceConfiguration.GETSRVINSTANCE);
+    private IpSecService(Context context, INetworkManagementService networkManager) {
+        this(context, networkManager, IpSecServiceConfiguration.GETSRVINSTANCE);
     }
 
-    static IpSecService create(Context context) throws InterruptedException {
-        final IpSecService service = new IpSecService(context);
+    static IpSecService create(Context context, INetworkManagementService networkManager)
+            throws InterruptedException {
+        final IpSecService service = new IpSecService(context, networkManager);
         service.connectNativeNetdService();
         return service;
     }
@@ -1008,9 +1016,11 @@
 
     /** @hide */
     @VisibleForTesting
-    public IpSecService(Context context, IpSecServiceConfiguration config) {
+    public IpSecService(Context context, INetworkManagementService networkManager,
+            IpSecServiceConfiguration config) {
         this(
                 context,
+                networkManager,
                 config,
                 (fd, uid) -> {
                     try {
@@ -1024,9 +1034,10 @@
 
     /** @hide */
     @VisibleForTesting
-    public IpSecService(
-            Context context, IpSecServiceConfiguration config, UidFdTagger uidFdTagger) {
+    public IpSecService(Context context, INetworkManagementService networkManager,
+            IpSecServiceConfiguration config, UidFdTagger uidFdTagger) {
         mContext = context;
+        mNetworkManager = Objects.requireNonNull(networkManager);
         mSrvConfig = config;
         mUidFdTagger = uidFdTagger;
     }
@@ -1101,7 +1112,7 @@
         if (requestedSpi > 0 && requestedSpi < 256) {
             throw new IllegalArgumentException("ESP SPI must not be in the range of 0-255.");
         }
-        checkNotNull(binder, "Null Binder passed to allocateSecurityParameterIndex");
+        Objects.requireNonNull(binder, "Null Binder passed to allocateSecurityParameterIndex");
 
         int callingUid = Binder.getCallingUid();
         UserRecord userRecord = mUserResourceTracker.getUserRecord(callingUid);
@@ -1218,7 +1229,7 @@
             throw new IllegalArgumentException(
                     "Specified port number must be a valid non-reserved UDP port");
         }
-        checkNotNull(binder, "Null Binder passed to openUdpEncapsulationSocket");
+        Objects.requireNonNull(binder, "Null Binder passed to openUdpEncapsulationSocket");
 
         int callingUid = Binder.getCallingUid();
         UserRecord userRecord = mUserResourceTracker.getUserRecord(callingUid);
@@ -1278,8 +1289,8 @@
             String localAddr, String remoteAddr, Network underlyingNetwork, IBinder binder,
             String callingPackage) {
         enforceTunnelFeatureAndPermissions(callingPackage);
-        checkNotNull(binder, "Null Binder passed to createTunnelInterface");
-        checkNotNull(underlyingNetwork, "No underlying network was specified");
+        Objects.requireNonNull(binder, "Null Binder passed to createTunnelInterface");
+        Objects.requireNonNull(underlyingNetwork, "No underlying network was specified");
         checkInetAddress(localAddr);
         checkInetAddress(remoteAddr);
 
@@ -1305,6 +1316,10 @@
             final INetd netd = mSrvConfig.getNetdInstance();
             netd.ipSecAddTunnelInterface(intfName, localAddr, remoteAddr, ikey, okey, resourceId);
 
+            Binder.withCleanCallingIdentity(() -> {
+                mNetworkManager.setInterfaceUp(intfName);
+            });
+
             for (int selAddrFamily : ADDRESS_FAMILIES) {
                 // Always send down correct local/remote addresses for template.
                 netd.ipSecAddSecurityPolicy(
@@ -1556,17 +1571,17 @@
                     "IPsec Tunnel Mode requires PackageManager.FEATURE_IPSEC_TUNNELS");
         }
 
-        checkNotNull(callingPackage, "Null calling package cannot create IpSec tunnels");
-        switch (getAppOpsManager().noteOp(TUNNEL_OP, Binder.getCallingUid(), callingPackage)) {
-            case AppOpsManager.MODE_DEFAULT:
-                mContext.enforceCallingOrSelfPermission(
-                        android.Manifest.permission.MANAGE_IPSEC_TUNNELS, "IpSecService");
-                break;
-            case AppOpsManager.MODE_ALLOWED:
-                return;
-            default:
-                throw new SecurityException("Request to ignore AppOps for non-legacy API");
+        Objects.requireNonNull(callingPackage, "Null calling package cannot create IpSec tunnels");
+
+        // OP_MANAGE_IPSEC_TUNNELS will return MODE_ERRORED by default, including for the system
+        // server. If the appop is not granted, require that the caller has the MANAGE_IPSEC_TUNNELS
+        // permission or is the System Server.
+        if (AppOpsManager.MODE_ALLOWED == getAppOpsManager().noteOpNoThrow(
+                TUNNEL_OP, Binder.getCallingUid(), callingPackage)) {
+            return;
         }
+        mContext.enforceCallingOrSelfPermission(
+                android.Manifest.permission.MANAGE_IPSEC_TUNNELS, "IpSecService");
     }
 
     private void createOrUpdateTransform(
@@ -1625,12 +1640,12 @@
     @Override
     public synchronized IpSecTransformResponse createTransform(
             IpSecConfig c, IBinder binder, String callingPackage) throws RemoteException {
-        checkNotNull(c);
+        Objects.requireNonNull(c);
         if (c.getMode() == IpSecTransform.MODE_TUNNEL) {
             enforceTunnelFeatureAndPermissions(callingPackage);
         }
         checkIpSecConfig(c);
-        checkNotNull(binder, "Null Binder passed to createTransform");
+        Objects.requireNonNull(binder, "Null Binder passed to createTransform");
         final int resourceId = mNextResourceId++;
 
         UserRecord userRecord = mUserResourceTracker.getUserRecord(Binder.getCallingUid());
diff --git a/services/core/java/com/android/server/NativeDaemonConnector.java b/services/core/java/com/android/server/NativeDaemonConnector.java
index ad02aad..eac767f 100644
--- a/services/core/java/com/android/server/NativeDaemonConnector.java
+++ b/services/core/java/com/android/server/NativeDaemonConnector.java
@@ -46,6 +46,7 @@
 import java.util.concurrent.CountDownLatch;
 import java.util.concurrent.TimeUnit;
 import java.util.LinkedList;
+import java.util.Objects;
 
 /**
  * Generic connector class for interfacing with a native daemon which uses the
@@ -126,7 +127,7 @@
      */
     public void setWarnIfHeld(Object warnIfHeld) {
         Preconditions.checkState(mWarnIfHeld == null);
-        mWarnIfHeld = Preconditions.checkNotNull(warnIfHeld);
+        mWarnIfHeld = Objects.requireNonNull(warnIfHeld);
     }
 
     @Override
diff --git a/services/core/java/com/android/server/NsdService.java b/services/core/java/com/android/server/NsdService.java
index 3efef01..4a1820a 100644
--- a/services/core/java/com/android/server/NsdService.java
+++ b/services/core/java/com/android/server/NsdService.java
@@ -16,19 +16,18 @@
 
 package com.android.server;
 
-import android.content.Context;
 import android.content.ContentResolver;
+import android.content.Context;
 import android.content.Intent;
-import android.content.pm.PackageManager;
 import android.database.ContentObserver;
+import android.net.NetworkStack;
 import android.net.Uri;
-import android.net.nsd.NsdServiceInfo;
-import android.net.nsd.DnsSdTxtRecord;
 import android.net.nsd.INsdManager;
 import android.net.nsd.NsdManager;
-import android.os.Binder;
-import android.os.HandlerThread;
+import android.net.nsd.NsdServiceInfo;
+import android.net.util.nsd.DnsSdTxtRecord;
 import android.os.Handler;
+import android.os.HandlerThread;
 import android.os.Message;
 import android.os.Messenger;
 import android.os.UserHandle;
@@ -38,6 +37,12 @@
 import android.util.SparseArray;
 import android.util.SparseIntArray;
 
+import com.android.internal.annotations.VisibleForTesting;
+import com.android.internal.util.AsyncChannel;
+import com.android.internal.util.DumpUtils;
+import com.android.internal.util.State;
+import com.android.internal.util.StateMachine;
+
 import java.io.FileDescriptor;
 import java.io.PrintWriter;
 import java.net.InetAddress;
@@ -45,13 +50,6 @@
 import java.util.HashMap;
 import java.util.concurrent.CountDownLatch;
 
-import com.android.internal.annotations.VisibleForTesting;
-import com.android.internal.util.AsyncChannel;
-import com.android.internal.util.DumpUtils;
-import com.android.internal.util.Protocol;
-import com.android.internal.util.State;
-import com.android.internal.util.StateMachine;
-
 /**
  * Network Service Discovery Service handles remote service discovery operation requests by
  * implementing the INsdManager interface.
@@ -565,8 +563,7 @@
     }
 
     public void setEnabled(boolean isEnabled) {
-        mContext.enforceCallingOrSelfPermission(android.Manifest.permission.CONNECTIVITY_INTERNAL,
-                "NsdService");
+        NetworkStack.checkNetworkStackPermission(mContext);
         mNsdSettings.putEnabledStatus(isEnabled);
         notifyEnabled(isEnabled);
     }
diff --git a/services/core/java/com/android/server/net/NetworkStatsFactory.java b/services/core/java/com/android/server/net/NetworkStatsFactory.java
index 3ca1803..75ffe35 100644
--- a/services/core/java/com/android/server/net/NetworkStatsFactory.java
+++ b/services/core/java/com/android/server/net/NetworkStatsFactory.java
@@ -229,7 +229,7 @@
                     entry.txPackets += reader.nextLong();
                 }
 
-                stats.addValues(entry);
+                stats.insertEntry(entry);
                 reader.finishLine();
             }
         } catch (NullPointerException|NumberFormatException e) {
@@ -279,7 +279,7 @@
                 entry.txBytes = reader.nextLong();
                 entry.txPackets = reader.nextLong();
 
-                stats.addValues(entry);
+                stats.insertEntry(entry);
                 reader.finishLine();
             }
         } catch (NullPointerException|NumberFormatException e) {
@@ -439,7 +439,7 @@
                 if ((limitIfaces == null || ArrayUtils.contains(limitIfaces, entry.iface))
                         && (limitUid == UID_ALL || limitUid == entry.uid)
                         && (limitTag == TAG_ALL || limitTag == entry.tag)) {
-                    stats.addValues(entry);
+                    stats.insertEntry(entry);
                 }
 
                 reader.finishLine();
diff --git a/services/core/java/com/android/server/net/NetworkStatsRecorder.java b/services/core/java/com/android/server/net/NetworkStatsRecorder.java
index 06ec341..a94a2f7 100644
--- a/services/core/java/com/android/server/net/NetworkStatsRecorder.java
+++ b/services/core/java/com/android/server/net/NetworkStatsRecorder.java
@@ -21,8 +21,6 @@
 import static android.net.TrafficStats.MB_IN_BYTES;
 import static android.text.format.DateUtils.YEAR_IN_MILLIS;
 
-import static com.android.internal.util.Preconditions.checkNotNull;
-
 import android.net.NetworkStats;
 import android.net.NetworkStats.NonMonotonicObserver;
 import android.net.NetworkStatsHistory;
@@ -54,6 +52,7 @@
 import java.util.Arrays;
 import java.util.HashSet;
 import java.util.Map;
+import java.util.Objects;
 
 /**
  * Logic to record deltas between periodic {@link NetworkStats} snapshots into
@@ -116,9 +115,9 @@
      */
     public NetworkStatsRecorder(FileRotator rotator, NonMonotonicObserver<String> observer,
             DropBoxManager dropBox, String cookie, long bucketDuration, boolean onlyTags) {
-        mRotator = checkNotNull(rotator, "missing FileRotator");
-        mObserver = checkNotNull(observer, "missing NonMonotonicObserver");
-        mDropBox = checkNotNull(dropBox, "missing DropBoxManager");
+        mRotator = Objects.requireNonNull(rotator, "missing FileRotator");
+        mObserver = Objects.requireNonNull(observer, "missing NonMonotonicObserver");
+        mDropBox = Objects.requireNonNull(dropBox, "missing DropBoxManager");
         mCookie = cookie;
 
         mBucketDuration = bucketDuration;
@@ -165,7 +164,7 @@
      * as reference is valid.
      */
     public NetworkStatsCollection getOrLoadCompleteLocked() {
-        checkNotNull(mRotator, "missing FileRotator");
+        Objects.requireNonNull(mRotator, "missing FileRotator");
         NetworkStatsCollection res = mComplete != null ? mComplete.get() : null;
         if (res == null) {
             res = loadLocked(Long.MIN_VALUE, Long.MAX_VALUE);
@@ -175,7 +174,7 @@
     }
 
     public NetworkStatsCollection getOrLoadPartialLocked(long start, long end) {
-        checkNotNull(mRotator, "missing FileRotator");
+        Objects.requireNonNull(mRotator, "missing FileRotator");
         NetworkStatsCollection res = mComplete != null ? mComplete.get() : null;
         if (res == null) {
             res = loadLocked(start, end);
@@ -280,7 +279,7 @@
      * {@link #mPersistThresholdBytes}.
      */
     public void maybePersistLocked(long currentTimeMillis) {
-        checkNotNull(mRotator, "missing FileRotator");
+        Objects.requireNonNull(mRotator, "missing FileRotator");
         final long pendingBytes = mPending.getTotalBytes();
         if (pendingBytes >= mPersistThresholdBytes) {
             forcePersistLocked(currentTimeMillis);
@@ -293,7 +292,7 @@
      * Force persisting any pending deltas.
      */
     public void forcePersistLocked(long currentTimeMillis) {
-        checkNotNull(mRotator, "missing FileRotator");
+        Objects.requireNonNull(mRotator, "missing FileRotator");
         if (mPending.isDirty()) {
             if (LOGD) Slog.d(TAG, "forcePersistLocked() writing for " + mCookie);
             try {
@@ -356,7 +355,7 @@
         private final NetworkStatsCollection mCollection;
 
         public CombiningRewriter(NetworkStatsCollection collection) {
-            mCollection = checkNotNull(collection, "missing NetworkStatsCollection");
+            mCollection = Objects.requireNonNull(collection, "missing NetworkStatsCollection");
         }
 
         @Override
@@ -418,7 +417,7 @@
     }
 
     public void importLegacyNetworkLocked(File file) throws IOException {
-        checkNotNull(mRotator, "missing FileRotator");
+        Objects.requireNonNull(mRotator, "missing FileRotator");
 
         // legacy file still exists; start empty to avoid double importing
         mRotator.deleteAll();
@@ -438,7 +437,7 @@
     }
 
     public void importLegacyUidLocked(File file) throws IOException {
-        checkNotNull(mRotator, "missing FileRotator");
+        Objects.requireNonNull(mRotator, "missing FileRotator");
 
         // legacy file still exists; start empty to avoid double importing
         mRotator.deleteAll();
diff --git a/services/core/java/com/android/server/net/NetworkStatsService.java b/services/core/java/com/android/server/net/NetworkStatsService.java
index 41806ca..2680858 100644
--- a/services/core/java/com/android/server/net/NetworkStatsService.java
+++ b/services/core/java/com/android/server/net/NetworkStatsService.java
@@ -17,17 +17,21 @@
 package com.android.server.net;
 
 import static android.Manifest.permission.ACCESS_NETWORK_STATE;
-import static android.Manifest.permission.CONNECTIVITY_INTERNAL;
+import static android.Manifest.permission.NETWORK_STATS_PROVIDER;
 import static android.Manifest.permission.READ_NETWORK_USAGE_HISTORY;
+import static android.Manifest.permission.UPDATE_DEVICE_STATS;
 import static android.content.Intent.ACTION_SHUTDOWN;
 import static android.content.Intent.ACTION_UID_REMOVED;
 import static android.content.Intent.ACTION_USER_REMOVED;
 import static android.content.Intent.EXTRA_UID;
+import static android.content.pm.PackageManager.PERMISSION_GRANTED;
 import static android.net.ConnectivityManager.ACTION_TETHER_STATE_CHANGED;
 import static android.net.ConnectivityManager.isNetworkTypeMobile;
+import static android.net.NetworkIdentity.SUBTYPE_COMBINED;
 import static android.net.NetworkStack.checkNetworkStackPermission;
 import static android.net.NetworkStats.DEFAULT_NETWORK_ALL;
 import static android.net.NetworkStats.IFACE_ALL;
+import static android.net.NetworkStats.IFACE_VT;
 import static android.net.NetworkStats.INTERFACES_ALL;
 import static android.net.NetworkStats.METERED_ALL;
 import static android.net.NetworkStats.ROAMING_ALL;
@@ -42,10 +46,12 @@
 import static android.net.NetworkStatsHistory.FIELD_ALL;
 import static android.net.NetworkTemplate.buildTemplateMobileWildcard;
 import static android.net.NetworkTemplate.buildTemplateWifiWildcard;
+import static android.net.NetworkTemplate.getCollapsedRatType;
 import static android.net.TrafficStats.KB_IN_BYTES;
 import static android.net.TrafficStats.MB_IN_BYTES;
 import static android.os.Trace.TRACE_TAG_NETWORK;
 import static android.provider.Settings.Global.NETSTATS_AUGMENT_ENABLED;
+import static android.provider.Settings.Global.NETSTATS_COMBINE_SUBTYPE_ENABLED;
 import static android.provider.Settings.Global.NETSTATS_DEV_BUCKET_DURATION;
 import static android.provider.Settings.Global.NETSTATS_DEV_DELETE_AGE;
 import static android.provider.Settings.Global.NETSTATS_DEV_PERSIST_BYTES;
@@ -61,17 +67,20 @@
 import static android.provider.Settings.Global.NETSTATS_UID_TAG_DELETE_AGE;
 import static android.provider.Settings.Global.NETSTATS_UID_TAG_PERSIST_BYTES;
 import static android.provider.Settings.Global.NETSTATS_UID_TAG_ROTATE_AGE;
+import static android.telephony.PhoneStateListener.LISTEN_NONE;
+import static android.telephony.PhoneStateListener.LISTEN_SERVICE_STATE;
+import static android.telephony.TelephonyManager.NETWORK_TYPE_UNKNOWN;
 import static android.text.format.DateUtils.DAY_IN_MILLIS;
 import static android.text.format.DateUtils.HOUR_IN_MILLIS;
 import static android.text.format.DateUtils.MINUTE_IN_MILLIS;
 import static android.text.format.DateUtils.SECOND_IN_MILLIS;
 
-import static com.android.internal.util.Preconditions.checkNotNull;
 import static com.android.server.NetworkManagementService.LIMIT_GLOBAL_ALERT;
 import static com.android.server.NetworkManagementSocketTagger.resetKernelUidStats;
 import static com.android.server.NetworkManagementSocketTagger.setKernelCounterSet;
 
 import android.annotation.NonNull;
+import android.annotation.Nullable;
 import android.app.AlarmManager;
 import android.app.PendingIntent;
 import android.app.usage.NetworkStatsManager;
@@ -91,17 +100,22 @@
 import android.net.NetworkCapabilities;
 import android.net.NetworkIdentity;
 import android.net.NetworkInfo;
+import android.net.NetworkStack;
 import android.net.NetworkState;
 import android.net.NetworkStats;
 import android.net.NetworkStats.NonMonotonicObserver;
 import android.net.NetworkStatsHistory;
 import android.net.NetworkTemplate;
 import android.net.TrafficStats;
+import android.net.netstats.provider.INetworkStatsProvider;
+import android.net.netstats.provider.INetworkStatsProviderCallback;
+import android.net.netstats.provider.NetworkStatsProvider;
 import android.os.BestClock;
 import android.os.Binder;
 import android.os.DropBoxManager;
 import android.os.Environment;
 import android.os.Handler;
+import android.os.HandlerExecutor;
 import android.os.HandlerThread;
 import android.os.IBinder;
 import android.os.INetworkManagementService;
@@ -109,6 +123,7 @@
 import android.os.Message;
 import android.os.Messenger;
 import android.os.PowerManager;
+import android.os.RemoteCallbackList;
 import android.os.RemoteException;
 import android.os.SystemClock;
 import android.os.Trace;
@@ -117,6 +132,8 @@
 import android.provider.Settings.Global;
 import android.service.NetworkInterfaceProto;
 import android.service.NetworkStatsServiceDumpProto;
+import android.telephony.PhoneStateListener;
+import android.telephony.ServiceState;
 import android.telephony.SubscriptionPlan;
 import android.telephony.TelephonyManager;
 import android.text.format.DateUtils;
@@ -138,7 +155,6 @@
 import com.android.internal.util.IndentingPrintWriter;
 import com.android.server.EventLogTags;
 import com.android.server.LocalServices;
-import com.android.server.connectivity.Tethering;
 
 import java.io.File;
 import java.io.FileDescriptor;
@@ -149,6 +165,10 @@
 import java.util.Arrays;
 import java.util.HashSet;
 import java.util.List;
+import java.util.Objects;
+import java.util.concurrent.Executor;
+import java.util.concurrent.Semaphore;
+import java.util.concurrent.TimeUnit;
 
 /**
  * Collect and persist detailed network statistics, and provide this data to
@@ -163,6 +183,7 @@
     private static final int MSG_PERFORM_POLL = 1;
     // Perform polling, persist network, and register the global alert again.
     private static final int MSG_PERFORM_POLL_REGISTER_ALERT = 2;
+    private static final int MSG_UPDATE_IFACES = 3;
 
     /** Flags to control detail level of poll event. */
     private static final int FLAG_PERSIST_NETWORK = 0x1;
@@ -176,7 +197,7 @@
      * This avoids firing the global alert too often on devices with high transfer speeds and
      * high quota.
      */
-    private static final int PERFORM_POLL_DELAY_MS = 1000;
+    private static final int DEFAULT_PERFORM_POLL_DELAY_MS = 1000;
 
     private static final String TAG_NETSTATS_ERROR = "netstats_error";
 
@@ -212,17 +233,27 @@
     /**
      * Virtual network interface for video telephony. This is for VT data usage counting purpose.
      */
-    public static final String VT_INTERFACE = "vt_data0";
+    // TODO: Remove this after no one is using it.
+    public static final String VT_INTERFACE = NetworkStats.IFACE_VT;
 
     /**
      * Settings that can be changed externally.
      */
     public interface NetworkStatsSettings {
-        public long getPollInterval();
-        public boolean getSampleEnabled();
-        public boolean getAugmentEnabled();
+        long getPollInterval();
+        long getPollDelay();
+        boolean getSampleEnabled();
+        boolean getAugmentEnabled();
+        /**
+         * When enabled, all mobile data is reported under {@link NetworkIdentity#SUBTYPE_COMBINED}.
+         * When disabled, mobile data is broken down by a granular subtype representative of the
+         * actual subtype. {@see NetworkTemplate#getCollapsedRatType}.
+         * Enabling this decreases the level of detail but saves performance, disk space and
+         * amount of data logged.
+         */
+        boolean getCombineSubtypeEnabled();
 
-        public static class Config {
+        class Config {
             public final long bucketDuration;
             public final long rotateAgeMillis;
             public final long deleteAgeMillis;
@@ -234,16 +265,16 @@
             }
         }
 
-        public Config getDevConfig();
-        public Config getXtConfig();
-        public Config getUidConfig();
-        public Config getUidTagConfig();
+        Config getDevConfig();
+        Config getXtConfig();
+        Config getUidConfig();
+        Config getUidTagConfig();
 
-        public long getGlobalAlertBytes(long def);
-        public long getDevPersistBytes(long def);
-        public long getXtPersistBytes(long def);
-        public long getUidPersistBytes(long def);
-        public long getUidTagPersistBytes(long def);
+        long getGlobalAlertBytes(long def);
+        long getDevPersistBytes(long def);
+        long getXtPersistBytes(long def);
+        long getUidPersistBytes(long def);
+        long getUidTagPersistBytes(long def);
     }
 
     private final Object mStatsLock = new Object();
@@ -268,9 +299,20 @@
     @GuardedBy("mStatsLock")
     private Network[] mDefaultNetworks = new Network[0];
 
+    /** Last states of all networks sent from ConnectivityService. */
+    @GuardedBy("mStatsLock")
+    @Nullable
+    private NetworkState[] mLastNetworkStates = null;
+
     private final DropBoxNonMonotonicObserver mNonMonotonicObserver =
             new DropBoxNonMonotonicObserver();
 
+    private static final int MAX_STATS_PROVIDER_POLL_WAIT_TIME_MS = 100;
+    private final RemoteCallbackList<NetworkStatsProviderCallbackImpl> mStatsProviderCbList =
+            new RemoteCallbackList<>();
+    /** Semaphore used to wait for stats provider to respond to request stats update. */
+    private final Semaphore mStatsProviderSem = new Semaphore(0, true);
+
     @GuardedBy("mStatsLock")
     private NetworkStatsRecorder mDevRecorder;
     @GuardedBy("mStatsLock")
@@ -290,9 +332,8 @@
     /** Data layer operation counters for splicing into other structures. */
     private NetworkStats mUidOperations = new NetworkStats(0L, 10);
 
-    /** Must be set in factory by calling #setHandler. */
-    private Handler mHandler;
-    private Handler.Callback mHandlerCallback;
+    @NonNull
+    private final Handler mHandler;
 
     private volatile boolean mSystemReady;
     private long mPersistThreshold = 2 * MB_IN_BYTES;
@@ -308,6 +349,9 @@
 
     private final static int DUMP_STATS_SESSION_COUNT = 20;
 
+    @NonNull
+    private final Dependencies mDeps;
+
     private static @NonNull File getDefaultSystemDir() {
         return new File(Environment.getDataDirectory(), "system");
     }
@@ -323,9 +367,30 @@
                 Clock.systemUTC());
     }
 
-    private static final class NetworkStatsHandler extends Handler {
-        NetworkStatsHandler(Looper looper, Handler.Callback callback) {
-            super(looper, callback);
+    private final class NetworkStatsHandler extends Handler {
+        NetworkStatsHandler(@NonNull Looper looper) {
+            super(looper);
+        }
+
+        @Override
+        public void handleMessage(Message msg) {
+            switch (msg.what) {
+                case MSG_PERFORM_POLL: {
+                    performPoll(FLAG_PERSIST_ALL);
+                    break;
+                }
+                case MSG_UPDATE_IFACES: {
+                    // If no cached states, ignore.
+                    if (mLastNetworkStates == null) break;
+                    updateIfaces(mDefaultNetworks, mLastNetworkStates, mActiveIface);
+                    break;
+                }
+                case MSG_PERFORM_POLL_REGISTER_ALERT: {
+                    performPoll(FLAG_PERSIST_NETWORK);
+                    registerGlobalAlert();
+                    break;
+                }
+            }
         }
     }
 
@@ -337,16 +402,12 @@
                 powerManager.newWakeLock(PowerManager.PARTIAL_WAKE_LOCK, TAG);
 
         NetworkStatsService service = new NetworkStatsService(context, networkManager, alarmManager,
-                wakeLock, getDefaultClock(), TelephonyManager.getDefault(),
+                wakeLock, getDefaultClock(), context.getSystemService(TelephonyManager.class),
                 new DefaultNetworkStatsSettings(context), new NetworkStatsFactory(),
-                new NetworkStatsObservers(), getDefaultSystemDir(), getDefaultBaseDir());
+                new NetworkStatsObservers(), getDefaultSystemDir(), getDefaultBaseDir(),
+                new Dependencies());
         service.registerLocalService();
 
-        HandlerThread handlerThread = new HandlerThread(TAG);
-        Handler.Callback callback = new HandlerCallback(service);
-        handlerThread.start();
-        Handler handler = new NetworkStatsHandler(handlerThread.getLooper(), callback);
-        service.setHandler(handler, callback);
         return service;
     }
 
@@ -357,19 +418,41 @@
             AlarmManager alarmManager, PowerManager.WakeLock wakeLock, Clock clock,
             TelephonyManager teleManager, NetworkStatsSettings settings,
             NetworkStatsFactory factory, NetworkStatsObservers statsObservers, File systemDir,
-            File baseDir) {
-        mContext = checkNotNull(context, "missing Context");
-        mNetworkManager = checkNotNull(networkManager, "missing INetworkManagementService");
-        mAlarmManager = checkNotNull(alarmManager, "missing AlarmManager");
-        mClock = checkNotNull(clock, "missing Clock");
-        mSettings = checkNotNull(settings, "missing NetworkStatsSettings");
-        mTeleManager = checkNotNull(teleManager, "missing TelephonyManager");
-        mWakeLock = checkNotNull(wakeLock, "missing WakeLock");
-        mStatsFactory = checkNotNull(factory, "missing factory");
-        mStatsObservers = checkNotNull(statsObservers, "missing NetworkStatsObservers");
-        mSystemDir = checkNotNull(systemDir, "missing systemDir");
-        mBaseDir = checkNotNull(baseDir, "missing baseDir");
+            File baseDir, @NonNull Dependencies deps) {
+        mContext = Objects.requireNonNull(context, "missing Context");
+        mNetworkManager = Objects.requireNonNull(networkManager,
+            "missing INetworkManagementService");
+        mAlarmManager = Objects.requireNonNull(alarmManager, "missing AlarmManager");
+        mClock = Objects.requireNonNull(clock, "missing Clock");
+        mSettings = Objects.requireNonNull(settings, "missing NetworkStatsSettings");
+        mTeleManager = Objects.requireNonNull(teleManager, "missing TelephonyManager");
+        mWakeLock = Objects.requireNonNull(wakeLock, "missing WakeLock");
+        mStatsFactory = Objects.requireNonNull(factory, "missing factory");
+        mStatsObservers = Objects.requireNonNull(statsObservers, "missing NetworkStatsObservers");
+        mSystemDir = Objects.requireNonNull(systemDir, "missing systemDir");
+        mBaseDir = Objects.requireNonNull(baseDir, "missing baseDir");
         mUseBpfTrafficStats = new File("/sys/fs/bpf/map_netd_app_uid_stats_map").exists();
+        mDeps = Objects.requireNonNull(deps, "missing Dependencies");
+
+        final HandlerThread handlerThread = mDeps.makeHandlerThread();
+        handlerThread.start();
+        mHandler = new NetworkStatsHandler(handlerThread.getLooper());
+        mPhoneListener = new NetworkTypeListener(new HandlerExecutor(mHandler));
+    }
+
+    /**
+     * Dependencies of NetworkStatsService, for injection in tests.
+     */
+    // TODO: Move more stuff into dependencies object.
+    @VisibleForTesting
+    public static class Dependencies {
+        /**
+         * Create a HandlerThread to use in NetworkStatsService.
+         */
+        @NonNull
+        public HandlerThread makeHandlerThread() {
+            return new HandlerThread(TAG);
+        }
     }
 
     private void registerLocalService() {
@@ -377,12 +460,6 @@
                 new NetworkStatsManagerInternalImpl());
     }
 
-    @VisibleForTesting
-    void setHandler(Handler handler, Handler.Callback callback) {
-        mHandler = handler;
-        mHandlerCallback = callback;
-    }
-
     public void systemReady() {
         synchronized (mStatsLock) {
             mSystemReady = true;
@@ -440,6 +517,13 @@
         mAlarmManager.setInexactRepeating(AlarmManager.ELAPSED_REALTIME, currentRealtime,
                 mSettings.getPollInterval(), pollIntent);
 
+        // TODO: 1. listen to changes from all subscriptions.
+        //       2. listen to settings changed to support dynamically enable/disable.
+        // watch for networkType changes
+        if (!mSettings.getCombineSubtypeEnabled()) {
+            mTeleManager.listen(mPhoneListener, LISTEN_SERVICE_STATE);
+        }
+
         registerGlobalAlert();
     }
 
@@ -460,6 +544,8 @@
         mContext.unregisterReceiver(mUserReceiver);
         mContext.unregisterReceiver(mShutdownReceiver);
 
+        mTeleManager.listen(mPhoneListener, LISTEN_NONE);
+
         final long currentTime = mClock.millis();
 
         // persist any pending stats
@@ -500,9 +586,9 @@
     }
 
     /**
-     * Register for a global alert that is delivered through
-     * {@link INetworkManagementEventObserver} once a threshold amount of data
-     * has been transferred.
+     * Register for a global alert that is delivered through {@link INetworkManagementEventObserver}
+     * or {@link NetworkStatsProviderCallback#onAlertReached()} once a threshold amount of data has
+     * been transferred.
      */
     private void registerGlobalAlert() {
         try {
@@ -512,6 +598,7 @@
         } catch (RemoteException e) {
             // ignored; service lives in system_server
         }
+        invokeForAllStatsProviderCallbacks((cb) -> cb.mProvider.onSetAlert(mGlobalAlertBytes));
     }
 
     @Override
@@ -712,7 +799,7 @@
         final NetworkStatsHistory.Entry entry = history.getValues(start, end, now, null);
 
         final NetworkStats stats = new NetworkStats(end - start, 1);
-        stats.addValues(new NetworkStats.Entry(IFACE_ALL, UID_ALL, SET_ALL, TAG_NONE,
+        stats.insertEntry(new NetworkStats.Entry(IFACE_ALL, UID_ALL, SET_ALL, TAG_NONE,
                 METERED_ALL, ROAMING_ALL, DEFAULT_NETWORK_ALL, entry.rxBytes, entry.rxPackets,
                 entry.txBytes, entry.txPackets, entry.operations));
         return stats;
@@ -801,8 +888,7 @@
     @Override
     public void incrementOperationCount(int uid, int tag, int operationCount) {
         if (Binder.getCallingUid() != uid) {
-            mContext.enforceCallingOrSelfPermission(
-                    android.Manifest.permission.UPDATE_DEVICE_STATS, TAG);
+            mContext.enforceCallingOrSelfPermission(UPDATE_DEVICE_STATS, TAG);
         }
 
         if (operationCount < 0) {
@@ -874,6 +960,8 @@
                     + mPersistThreshold);
         }
 
+        final long oldGlobalAlertBytes = mGlobalAlertBytes;
+
         // update and persist if beyond new thresholds
         final long currentTime = mClock.millis();
         synchronized (mStatsLock) {
@@ -887,18 +975,19 @@
             mUidTagRecorder.maybePersistLocked(currentTime);
         }
 
-        // re-arm global alert
-        registerGlobalAlert();
+        if (oldGlobalAlertBytes != mGlobalAlertBytes) {
+            registerGlobalAlert();
+        }
     }
 
     @Override
     public DataUsageRequest registerUsageCallback(String callingPackage,
                 DataUsageRequest request, Messenger messenger, IBinder binder) {
-        checkNotNull(callingPackage, "calling package is null");
-        checkNotNull(request, "DataUsageRequest is null");
-        checkNotNull(request.template, "NetworkTemplate is null");
-        checkNotNull(messenger, "messenger is null");
-        checkNotNull(binder, "binder is null");
+        Objects.requireNonNull(callingPackage, "calling package is null");
+        Objects.requireNonNull(request, "DataUsageRequest is null");
+        Objects.requireNonNull(request.template, "NetworkTemplate is null");
+        Objects.requireNonNull(messenger, "messenger is null");
+        Objects.requireNonNull(binder, "binder is null");
 
         int callingUid = Binder.getCallingUid();
         @NetworkStatsAccess.Level int accessLevel = checkAccessLevel(callingPackage);
@@ -919,7 +1008,7 @@
 
     @Override
     public void unregisterUsageRequest(DataUsageRequest request) {
-        checkNotNull(request, "DataUsageRequest is null");
+        Objects.requireNonNull(request, "DataUsageRequest is null");
 
         int callingUid = Binder.getCallingUid();
         final long token = Binder.clearCallingIdentity();
@@ -1021,8 +1110,6 @@
     private BroadcastReceiver mTetherReceiver = new BroadcastReceiver() {
         @Override
         public void onReceive(Context context, Intent intent) {
-            // on background handler thread, and verified CONNECTIVITY_INTERNAL
-            // permission above.
             performPoll(FLAG_PERSIST_NETWORK);
         }
     };
@@ -1092,23 +1179,55 @@
     /**
      * Observer that watches for {@link INetworkManagementService} alerts.
      */
-    private INetworkManagementEventObserver mAlertObserver = new BaseNetworkObserver() {
+    private final INetworkManagementEventObserver mAlertObserver = new BaseNetworkObserver() {
         @Override
         public void limitReached(String limitName, String iface) {
             // only someone like NMS should be calling us
-            mContext.enforceCallingOrSelfPermission(CONNECTIVITY_INTERNAL, TAG);
+            NetworkStack.checkNetworkStackPermission(mContext);
 
             if (LIMIT_GLOBAL_ALERT.equals(limitName)) {
                 // kick off background poll to collect network stats unless there is already
                 // such a call pending; UID stats are handled during normal polling interval.
                 if (!mHandler.hasMessages(MSG_PERFORM_POLL_REGISTER_ALERT)) {
                     mHandler.sendEmptyMessageDelayed(MSG_PERFORM_POLL_REGISTER_ALERT,
-                            PERFORM_POLL_DELAY_MS);
+                            mSettings.getPollDelay());
                 }
             }
         }
     };
 
+    /**
+     * Receiver that watches for {@link TelephonyManager} changes, such as
+     * transitioning between Radio Access Technology(RAT) types.
+     */
+    @NonNull
+    private final NetworkTypeListener mPhoneListener;
+
+    class NetworkTypeListener extends PhoneStateListener {
+        private volatile int mLastCollapsedRatType = NETWORK_TYPE_UNKNOWN;
+
+        NetworkTypeListener(@NonNull Executor executor) {
+            super(executor);
+        }
+
+        @Override
+        public void onServiceStateChanged(@NonNull ServiceState ss) {
+            final int networkType = ss.getDataNetworkType();
+            final int collapsedRatType = getCollapsedRatType(networkType);
+            if (collapsedRatType == mLastCollapsedRatType) return;
+
+            if (LOGD) {
+                Log.d(TAG, "subtype changed for mobile: "
+                        + mLastCollapsedRatType + " -> " + collapsedRatType);
+            }
+            // Protect service from frequently updating. Remove pending messages if any.
+            mHandler.removeMessages(MSG_UPDATE_IFACES);
+            mLastCollapsedRatType = collapsedRatType;
+            mHandler.sendMessageDelayed(
+                    mHandler.obtainMessage(MSG_UPDATE_IFACES), mSettings.getPollDelay());
+        }
+    }
+
     private void updateIfaces(
             Network[] defaultNetworks,
             NetworkState[] networkStates,
@@ -1130,7 +1249,8 @@
      * they are combined under a single {@link NetworkIdentitySet}.
      */
     @GuardedBy("mStatsLock")
-    private void updateIfacesLocked(Network[] defaultNetworks, NetworkState[] states) {
+    private void updateIfacesLocked(@Nullable Network[] defaultNetworks,
+            @NonNull NetworkState[] states) {
         if (!mSystemReady) return;
         if (LOGV) Slog.v(TAG, "updateIfacesLocked()");
 
@@ -1150,13 +1270,18 @@
             mDefaultNetworks = defaultNetworks;
         }
 
+        mLastNetworkStates = states;
+
+        final boolean combineSubtypeEnabled = mSettings.getCombineSubtypeEnabled();
         final ArraySet<String> mobileIfaces = new ArraySet<>();
         for (NetworkState state : states) {
             if (state.networkInfo.isConnected()) {
                 final boolean isMobile = isNetworkTypeMobile(state.networkInfo.getType());
                 final boolean isDefault = ArrayUtils.contains(mDefaultNetworks, state.network);
+                final int subType = combineSubtypeEnabled ? SUBTYPE_COMBINED
+                        : getSubTypeForState(state);
                 final NetworkIdentity ident = NetworkIdentity.buildNetworkIdentity(mContext, state,
-                        isDefault);
+                        isDefault, subType);
 
                 // Traffic occurring on the base interface is always counted for
                 // both total usage and UID details.
@@ -1178,8 +1303,8 @@
                                 ident.getSubType(), ident.getSubscriberId(), ident.getNetworkId(),
                                 ident.getRoaming(), true /* metered */,
                                 true /* onDefaultNetwork */);
-                        findOrCreateNetworkIdentitySet(mActiveIfaces, VT_INTERFACE).add(vtIdent);
-                        findOrCreateNetworkIdentitySet(mActiveUidIfaces, VT_INTERFACE).add(vtIdent);
+                        findOrCreateNetworkIdentitySet(mActiveIfaces, IFACE_VT).add(vtIdent);
+                        findOrCreateNetworkIdentitySet(mActiveUidIfaces, IFACE_VT).add(vtIdent);
                     }
 
                     if (isMobile) {
@@ -1217,6 +1342,20 @@
         mMobileIfaces = mobileIfaces.toArray(new String[mobileIfaces.size()]);
     }
 
+    /**
+     * For networks with {@code TRANSPORT_CELLULAR}, get subType that was obtained through
+     * {@link PhoneStateListener}. Otherwise, return 0 given that other networks with different
+     * transport types do not actually fill this value.
+     */
+    private int getSubTypeForState(@NonNull NetworkState state) {
+        if (!state.networkCapabilities.hasTransport(NetworkCapabilities.TRANSPORT_CELLULAR)) {
+            return 0;
+        }
+
+        // TODO: return different subType for different subscriptions.
+        return mPhoneListener.mLastCollapsedRatType;
+    }
+
     private static <K> NetworkIdentitySet findOrCreateNetworkIdentitySet(
             ArrayMap<K, NetworkIdentitySet> map, K key) {
         NetworkIdentitySet ident = map.get(key);
@@ -1235,7 +1374,7 @@
         final NetworkStats uidSnapshot = getNetworkStatsUidDetail(INTERFACES_ALL);
         Trace.traceEnd(TRACE_TAG_NETWORK);
         Trace.traceBegin(TRACE_TAG_NETWORK, "snapshotXt");
-        final NetworkStats xtSnapshot = getNetworkStatsXt();
+        final NetworkStats xtSnapshot = readNetworkStatsSummaryXt();
         Trace.traceEnd(TRACE_TAG_NETWORK);
         Trace.traceBegin(TRACE_TAG_NETWORK, "snapshotDev");
         final NetworkStats devSnapshot = readNetworkStatsSummaryDev();
@@ -1249,6 +1388,14 @@
         xtSnapshot.combineAllValues(tetherSnapshot);
         devSnapshot.combineAllValues(tetherSnapshot);
 
+        // Snapshot for dev/xt stats from all custom stats providers. Counts per-interface data
+        // from stats providers that isn't already counted by dev and XT stats.
+        Trace.traceBegin(TRACE_TAG_NETWORK, "snapshotStatsProvider");
+        final NetworkStats providersnapshot = getNetworkStatsFromProviders(STATS_PER_IFACE);
+        Trace.traceEnd(TRACE_TAG_NETWORK);
+        xtSnapshot.combineAllValues(providersnapshot);
+        devSnapshot.combineAllValues(providersnapshot);
+
         // For xt/dev, we pass a null VPN array because usage is aggregated by UID, so VPN traffic
         // can't be reattributed to responsible apps.
         Trace.traceBegin(TRACE_TAG_NETWORK, "recordDev");
@@ -1315,6 +1462,26 @@
         final boolean persistUid = (flags & FLAG_PERSIST_UID) != 0;
         final boolean persistForce = (flags & FLAG_PERSIST_FORCE) != 0;
 
+        // Request asynchronous stats update from all providers for next poll. And wait a bit of
+        // time to allow providers report-in given that normally binder call should be fast.
+        // TODO: request with a valid token.
+        Trace.traceBegin(TRACE_TAG_NETWORK, "provider.requestStatsUpdate");
+        final int registeredCallbackCount = mStatsProviderCbList.getRegisteredCallbackCount();
+        mStatsProviderSem.drainPermits();
+        invokeForAllStatsProviderCallbacks(
+                (cb) -> cb.mProvider.onRequestStatsUpdate(0 /* unused */));
+        try {
+            mStatsProviderSem.tryAcquire(registeredCallbackCount,
+                    MAX_STATS_PROVIDER_POLL_WAIT_TIME_MS, TimeUnit.MILLISECONDS);
+        } catch (InterruptedException e) {
+            // Strictly speaking it's possible a provider happened to deliver between the timeout
+            // and the log, and that doesn't matter too much as this is just a debug log.
+            Log.d(TAG, "requestStatsUpdate - providers responded "
+                    + mStatsProviderSem.availablePermits()
+                    + "/" + registeredCallbackCount + " : " + e);
+        }
+        Trace.traceEnd(TRACE_TAG_NETWORK);
+
         // TODO: consider marking "untrusted" times in historical stats
         final long currentTime = mClock.millis();
 
@@ -1473,6 +1640,12 @@
         public void forceUpdate() {
             NetworkStatsService.this.forceUpdate();
         }
+
+        @Override
+        public void setStatsProviderLimitAsync(@NonNull String iface, long quota) {
+            Slog.v(TAG, "setStatsProviderLimitAsync(" + iface + "," + quota + ")");
+            invokeForAllStatsProviderCallbacks((cb) -> cb.mProvider.onSetLimit(iface, quota));
+        }
     }
 
     @Override
@@ -1536,6 +1709,12 @@
                 return;
             }
 
+            pw.println("Configs:");
+            pw.increaseIndent();
+            pw.printPair(NETSTATS_COMBINE_SUBTYPE_ENABLED, mSettings.getCombineSubtypeEnabled());
+            pw.println();
+            pw.decreaseIndent();
+
             pw.println("Active interfaces:");
             pw.increaseIndent();
             for (int i = 0; i < mActiveIfaces.size(); i++) {
@@ -1578,6 +1757,22 @@
             pw.decreaseIndent();
             pw.println();
 
+            pw.println("Stats Providers:");
+            pw.increaseIndent();
+            invokeForAllStatsProviderCallbacks((cb) -> {
+                pw.println(cb.mTag + " Xt:");
+                pw.increaseIndent();
+                pw.print(cb.getCachedStats(STATS_PER_IFACE).toString());
+                pw.decreaseIndent();
+                if (includeUid) {
+                    pw.println(cb.mTag + " Uid:");
+                    pw.increaseIndent();
+                    pw.print(cb.getCachedStats(STATS_PER_UID).toString());
+                    pw.decreaseIndent();
+                }
+            });
+            pw.decreaseIndent();
+
             pw.println("Dev stats:");
             pw.increaseIndent();
             mDevRecorder.dumpLocked(pw, fullHistory);
@@ -1675,17 +1870,11 @@
                 mUseBpfTrafficStats);
         uidSnapshot.combineAllValues(tetherSnapshot);
 
-        final TelephonyManager telephonyManager = (TelephonyManager) mContext.getSystemService(
-                Context.TELEPHONY_SERVICE);
-
-        // fold video calling data usage stats into uid snapshot
-        final NetworkStats vtStats = telephonyManager.getVtDataUsage(STATS_PER_UID);
-        if (vtStats != null) {
-            vtStats.filter(UID_ALL, ifaces, TAG_ALL);
-            mStatsFactory.apply464xlatAdjustments(uidSnapshot, vtStats,
-                    mUseBpfTrafficStats);
-            uidSnapshot.combineAllValues(vtStats);
-        }
+        // get a stale copy of uid stats snapshot provided by providers.
+        final NetworkStats providerStats = getNetworkStatsFromProviders(STATS_PER_UID);
+        providerStats.filter(UID_ALL, ifaces, TAG_ALL);
+        mStatsFactory.apply464xlatAdjustments(uidSnapshot, providerStats, mUseBpfTrafficStats);
+        uidSnapshot.combineAllValues(providerStats);
 
         uidSnapshot.combineAllValues(mUidOperations);
 
@@ -1693,24 +1882,6 @@
     }
 
     /**
-     * Return snapshot of current XT statistics with video calling data usage statistics.
-     */
-    private NetworkStats getNetworkStatsXt() throws RemoteException {
-        final NetworkStats xtSnapshot = readNetworkStatsSummaryXt();
-
-        final TelephonyManager telephonyManager = (TelephonyManager) mContext.getSystemService(
-                Context.TELEPHONY_SERVICE);
-
-        // Merge video calling data usage into XT
-        final NetworkStats vtSnapshot = telephonyManager.getVtDataUsage(STATS_PER_IFACE);
-        if (vtSnapshot != null) {
-            xtSnapshot.combineAllValues(vtSnapshot);
-        }
-
-        return xtSnapshot;
-    }
-
-    /**
      * Return snapshot of current tethering statistics. Will return empty
      * {@link NetworkStats} if any problems are encountered.
      */
@@ -1723,31 +1894,175 @@
         }
     }
 
-    @VisibleForTesting
-    static class HandlerCallback implements Handler.Callback {
-        private final NetworkStatsService mService;
+    // TODO: It is copied from ConnectivityService, consider refactor these check permission
+    //  functions to a proper util.
+    private boolean checkAnyPermissionOf(String... permissions) {
+        for (String permission : permissions) {
+            if (mContext.checkCallingOrSelfPermission(permission) == PERMISSION_GRANTED) {
+                return true;
+            }
+        }
+        return false;
+    }
 
-        HandlerCallback(NetworkStatsService service) {
-            this.mService = service;
+    private void enforceAnyPermissionOf(String... permissions) {
+        if (!checkAnyPermissionOf(permissions)) {
+            throw new SecurityException("Requires one of the following permissions: "
+                    + String.join(", ", permissions) + ".");
+        }
+    }
+
+    /**
+     * Registers a custom provider of {@link android.net.NetworkStats} to combine the network
+     * statistics that cannot be seen by the kernel to system. To unregister, invoke the
+     * {@code unregister()} of the returned callback.
+     *
+     * @param tag a human readable identifier of the custom network stats provider.
+     * @param provider the {@link INetworkStatsProvider} binder corresponding to the
+     *                 {@link NetworkStatsProvider} to be registered.
+     *
+     * @return a {@link INetworkStatsProviderCallback} binder
+     *         interface, which can be used to report events to the system.
+     */
+    public @NonNull INetworkStatsProviderCallback registerNetworkStatsProvider(
+            @NonNull String tag, @NonNull INetworkStatsProvider provider) {
+        enforceAnyPermissionOf(NETWORK_STATS_PROVIDER,
+                NetworkStack.PERMISSION_MAINLINE_NETWORK_STACK);
+        Objects.requireNonNull(provider, "provider is null");
+        Objects.requireNonNull(tag, "tag is null");
+        try {
+            NetworkStatsProviderCallbackImpl callback = new NetworkStatsProviderCallbackImpl(
+                    tag, provider, mStatsProviderSem, mAlertObserver,
+                    mStatsProviderCbList);
+            mStatsProviderCbList.register(callback);
+            Log.d(TAG, "registerNetworkStatsProvider from " + callback.mTag + " uid/pid="
+                    + getCallingUid() + "/" + getCallingPid());
+            return callback;
+        } catch (RemoteException e) {
+            Log.e(TAG, "registerNetworkStatsProvider failed", e);
+        }
+        return null;
+    }
+
+    // Collect stats from local cache of providers.
+    private @NonNull NetworkStats getNetworkStatsFromProviders(int how) {
+        final NetworkStats ret = new NetworkStats(0L, 0);
+        invokeForAllStatsProviderCallbacks((cb) -> ret.combineAllValues(cb.getCachedStats(how)));
+        return ret;
+    }
+
+    @FunctionalInterface
+    private interface ThrowingConsumer<S, T extends Throwable> {
+        void accept(S s) throws T;
+    }
+
+    private void invokeForAllStatsProviderCallbacks(
+            @NonNull ThrowingConsumer<NetworkStatsProviderCallbackImpl, RemoteException> task) {
+        synchronized (mStatsLock) {
+            final int length = mStatsProviderCbList.beginBroadcast();
+            try {
+                for (int i = 0; i < length; i++) {
+                    final NetworkStatsProviderCallbackImpl cb =
+                            mStatsProviderCbList.getBroadcastItem(i);
+                    try {
+                        task.accept(cb);
+                    } catch (RemoteException e) {
+                        Log.e(TAG, "Fail to broadcast to provider: " + cb.mTag, e);
+                    }
+                }
+            } finally {
+                mStatsProviderCbList.finishBroadcast();
+            }
+        }
+    }
+
+    private static class NetworkStatsProviderCallbackImpl extends INetworkStatsProviderCallback.Stub
+            implements IBinder.DeathRecipient {
+        @NonNull final String mTag;
+
+        @NonNull final INetworkStatsProvider mProvider;
+        @NonNull private final Semaphore mSemaphore;
+        @NonNull final INetworkManagementEventObserver mAlertObserver;
+        @NonNull final RemoteCallbackList<NetworkStatsProviderCallbackImpl> mStatsProviderCbList;
+
+        @NonNull private final Object mProviderStatsLock = new Object();
+
+        @GuardedBy("mProviderStatsLock")
+        // Track STATS_PER_IFACE and STATS_PER_UID separately.
+        private final NetworkStats mIfaceStats = new NetworkStats(0L, 0);
+        @GuardedBy("mProviderStatsLock")
+        private final NetworkStats mUidStats = new NetworkStats(0L, 0);
+
+        NetworkStatsProviderCallbackImpl(
+                @NonNull String tag, @NonNull INetworkStatsProvider provider,
+                @NonNull Semaphore semaphore,
+                @NonNull INetworkManagementEventObserver alertObserver,
+                @NonNull RemoteCallbackList<NetworkStatsProviderCallbackImpl> cbList)
+                throws RemoteException {
+            mTag = tag;
+            mProvider = provider;
+            mProvider.asBinder().linkToDeath(this, 0);
+            mSemaphore = semaphore;
+            mAlertObserver = alertObserver;
+            mStatsProviderCbList = cbList;
+        }
+
+        @NonNull
+        public NetworkStats getCachedStats(int how) {
+            synchronized (mProviderStatsLock) {
+                NetworkStats stats;
+                switch (how) {
+                    case STATS_PER_IFACE:
+                        stats = mIfaceStats;
+                        break;
+                    case STATS_PER_UID:
+                        stats = mUidStats;
+                        break;
+                    default:
+                        throw new IllegalArgumentException("Invalid type: " + how);
+                }
+                // Callers might be able to mutate the returned object. Return a defensive copy
+                // instead of local reference.
+                return stats.clone();
+            }
         }
 
         @Override
-        public boolean handleMessage(Message msg) {
-            switch (msg.what) {
-                case MSG_PERFORM_POLL: {
-                    mService.performPoll(FLAG_PERSIST_ALL);
-                    return true;
-                }
-                case MSG_PERFORM_POLL_REGISTER_ALERT: {
-                    mService.performPoll(FLAG_PERSIST_NETWORK);
-                    mService.registerGlobalAlert();
-                    return true;
-                }
-                default: {
-                    return false;
-                }
+        public void notifyStatsUpdated(int token, @Nullable NetworkStats ifaceStats,
+                @Nullable NetworkStats uidStats) {
+            // TODO: 1. Use token to map ifaces to correct NetworkIdentity.
+            //       2. Store the difference and store it directly to the recorder.
+            synchronized (mProviderStatsLock) {
+                if (ifaceStats != null) mIfaceStats.combineAllValues(ifaceStats);
+                if (uidStats != null) mUidStats.combineAllValues(uidStats);
             }
+            mSemaphore.release();
         }
+
+        @Override
+        public void notifyAlertReached() throws RemoteException {
+            mAlertObserver.limitReached(LIMIT_GLOBAL_ALERT, null /* unused */);
+        }
+
+        @Override
+        public void notifyLimitReached() {
+            Log.d(TAG, mTag + ": onLimitReached");
+            LocalServices.getService(NetworkPolicyManagerInternal.class)
+                    .onStatsProviderLimitReached(mTag);
+        }
+
+        @Override
+        public void binderDied() {
+            Log.d(TAG, mTag + ": binderDied");
+            mStatsProviderCbList.unregister(this);
+        }
+
+        @Override
+        public void unregister() {
+            Log.d(TAG, mTag + ": unregister");
+            mStatsProviderCbList.unregister(this);
+        }
+
     }
 
     private void assertSystemReady() {
@@ -1795,7 +2110,7 @@
         private final ContentResolver mResolver;
 
         public DefaultNetworkStatsSettings(Context context) {
-            mResolver = checkNotNull(context.getContentResolver());
+            mResolver = Objects.requireNonNull(context.getContentResolver());
             // TODO: adjust these timings for production builds
         }
 
@@ -1812,6 +2127,10 @@
             return getGlobalLong(NETSTATS_POLL_INTERVAL, 30 * MINUTE_IN_MILLIS);
         }
         @Override
+        public long getPollDelay() {
+            return DEFAULT_PERFORM_POLL_DELAY_MS;
+        }
+        @Override
         public long getGlobalAlertBytes(long def) {
             return getGlobalLong(NETSTATS_GLOBAL_ALERT_BYTES, def);
         }
@@ -1824,6 +2143,10 @@
             return getGlobalBoolean(NETSTATS_AUGMENT_ENABLED, true);
         }
         @Override
+        public boolean getCombineSubtypeEnabled() {
+            return getGlobalBoolean(NETSTATS_COMBINE_SUBTYPE_ENABLED, false);
+        }
+        @Override
         public Config getDevConfig() {
             return new Config(getGlobalLong(NETSTATS_DEV_BUCKET_DURATION, HOUR_IN_MILLIS),
                     getGlobalLong(NETSTATS_DEV_ROTATE_AGE, 15 * DAY_IN_MILLIS),
diff --git a/services/core/java/com/android/server/net/NetworkStatsSubscriptionsMonitor.java b/services/core/java/com/android/server/net/NetworkStatsSubscriptionsMonitor.java
new file mode 100644
index 0000000..16a63d5
--- /dev/null
+++ b/services/core/java/com/android/server/net/NetworkStatsSubscriptionsMonitor.java
@@ -0,0 +1,211 @@
+/*
+ * Copyright (C) 2020 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 com.android.server.net;
+
+import static android.net.NetworkTemplate.getCollapsedRatType;
+
+import android.annotation.NonNull;
+import android.content.Context;
+import android.telephony.Annotation;
+import android.telephony.PhoneStateListener;
+import android.telephony.ServiceState;
+import android.telephony.SubscriptionManager;
+import android.telephony.TelephonyManager;
+import android.text.TextUtils;
+import android.util.Log;
+
+import com.android.internal.util.CollectionUtils;
+
+import java.util.ArrayList;
+import java.util.List;
+import java.util.concurrent.CopyOnWriteArrayList;
+import java.util.concurrent.Executor;
+
+/**
+ * Helper class that watches for events that are triggered per subscription.
+ */
+// TODO (b/152176562): Write tests to verify subscription changes generate corresponding
+//  register/unregister calls.
+public class NetworkStatsSubscriptionsMonitor extends
+        SubscriptionManager.OnSubscriptionsChangedListener {
+
+    /**
+     * Interface that this monitor uses to delegate event handling to NetworkStatsService.
+     */
+    public interface Delegate {
+        /**
+         * Notify that the collapsed RAT type has been changed for any subscription. The method
+         * will also be triggered for any existing sub when start and stop monitoring.
+         *
+         * @param subscriberId IMSI of the subscription.
+         * @param collapsedRatType collapsed RAT type.
+         *                         @see android.net.NetworkTemplate#getCollapsedRatType(int).
+         */
+        void onCollapsedRatTypeChanged(@NonNull String subscriberId,
+                @Annotation.NetworkType int collapsedRatType);
+    }
+    private final Delegate mDelegate;
+
+    /**
+     * Receivers that watches for {@link ServiceState} changes for each subscription, to
+     * monitor the transitioning between Radio Access Technology(RAT) types for each sub.
+     */
+    @NonNull
+    private final CopyOnWriteArrayList<RatTypeListener> mRatListeners =
+            new CopyOnWriteArrayList<>();
+
+    @NonNull
+    private final SubscriptionManager mSubscriptionManager;
+    @NonNull
+    private final TelephonyManager mTeleManager;
+
+    @NonNull
+    private final Executor mExecutor;
+
+    NetworkStatsSubscriptionsMonitor(@NonNull Context context, @NonNull Executor executor,
+            @NonNull Delegate delegate) {
+        super();
+        mSubscriptionManager = (SubscriptionManager) context.getSystemService(
+                Context.TELEPHONY_SUBSCRIPTION_SERVICE);
+        mTeleManager = (TelephonyManager) context.getSystemService(Context.TELEPHONY_SERVICE);
+        mExecutor = executor;
+        mDelegate = delegate;
+    }
+
+    @Override
+    public void onSubscriptionsChanged() {
+        // Collect active subId list, hidden subId such as opportunistic subscriptions are
+        // also needed to track CBRS.
+        final List<Integer> newSubs = getActiveSubIdList(mSubscriptionManager);
+
+        for (final int subId : newSubs) {
+            final RatTypeListener match = CollectionUtils.find(mRatListeners,
+                    it -> it.mSubId == subId);
+            if (match != null) continue;
+
+            // Create listener for every newly added sub. Also store subscriberId into it to
+            // prevent binder call to telephony when querying RAT.
+            final String subscriberId = mTeleManager.getSubscriberId(subId);
+            if (TextUtils.isEmpty(subscriberId)) {
+                Log.wtf(NetworkStatsService.TAG,
+                        "Empty subscriberId for newly added sub: " + subId);
+            }
+            final RatTypeListener listener =
+                    new RatTypeListener(mExecutor, this, subId, subscriberId);
+            mRatListeners.add(listener);
+
+            // Register listener to the telephony manager that associated with specific sub.
+            mTeleManager.createForSubscriptionId(subId)
+                    .listen(listener, PhoneStateListener.LISTEN_SERVICE_STATE);
+        }
+
+        for (final RatTypeListener listener : new ArrayList<>(mRatListeners)) {
+            // If the new list contains the subId of the listener, keeps it.
+            final Integer match = CollectionUtils.find(newSubs, it -> it == listener.mSubId);
+            if (match != null) continue;
+
+            handleRemoveRatTypeListener(listener);
+        }
+    }
+
+    @NonNull
+    private List<Integer> getActiveSubIdList(@NonNull SubscriptionManager subscriptionManager) {
+        final ArrayList<Integer> ret = new ArrayList<>();
+        final int[] ids = subscriptionManager.getActiveAndHiddenSubscriptionIdList();
+        for (int id : ids) ret.add(id);
+        return ret;
+    }
+
+    /**
+     * Get a collapsed RatType for the given subscriberId.
+     *
+     * @param subscriberId the target subscriberId
+     * @return collapsed RatType for the given subscriberId
+     */
+    public int getRatTypeForSubscriberId(@NonNull String subscriberId) {
+        final RatTypeListener match = CollectionUtils.find(mRatListeners,
+                it -> TextUtils.equals(subscriberId, it.mSubscriberId));
+        return match != null ? match.mLastCollapsedRatType : TelephonyManager.NETWORK_TYPE_UNKNOWN;
+    }
+
+    /**
+     * Start monitoring events that triggered per subscription.
+     */
+    public void start() {
+        mSubscriptionManager.addOnSubscriptionsChangedListener(mExecutor, this);
+    }
+
+    /**
+     * Unregister subscription changes and all listeners for each subscription.
+     */
+    public void stop() {
+        mSubscriptionManager.removeOnSubscriptionsChangedListener(this);
+
+        for (final RatTypeListener listener : new ArrayList<>(mRatListeners)) {
+            handleRemoveRatTypeListener(listener);
+        }
+    }
+
+    private void handleRemoveRatTypeListener(@NonNull RatTypeListener listener) {
+        mTeleManager.createForSubscriptionId(listener.mSubId)
+                .listen(listener, PhoneStateListener.LISTEN_NONE);
+        mRatListeners.remove(listener);
+
+        // Removal of subscriptions doesn't generate RAT changed event, fire it for every
+        // RatTypeListener.
+        mDelegate.onCollapsedRatTypeChanged(
+                listener.mSubscriberId, TelephonyManager.NETWORK_TYPE_UNKNOWN);
+    }
+
+    static class RatTypeListener extends PhoneStateListener {
+        // Unique id for the subscription. See {@link SubscriptionInfo#getSubscriptionId}.
+        @NonNull
+        private final int mSubId;
+
+        // IMSI to identifying the corresponding network from {@link NetworkState}.
+        // See {@link TelephonyManager#getSubscriberId}.
+        @NonNull
+        private final String mSubscriberId;
+
+        private volatile int mLastCollapsedRatType = TelephonyManager.NETWORK_TYPE_UNKNOWN;
+        @NonNull
+        private final NetworkStatsSubscriptionsMonitor mMonitor;
+
+        RatTypeListener(@NonNull Executor executor,
+                @NonNull NetworkStatsSubscriptionsMonitor monitor, int subId,
+                @NonNull String subscriberId) {
+            super(executor);
+            mSubId = subId;
+            mSubscriberId = subscriberId;
+            mMonitor = monitor;
+        }
+
+        @Override
+        public void onServiceStateChanged(@NonNull ServiceState ss) {
+            final int networkType = ss.getDataNetworkType();
+            final int collapsedRatType = getCollapsedRatType(networkType);
+            if (collapsedRatType == mLastCollapsedRatType) return;
+
+            if (NetworkStatsService.LOGD) {
+                Log.d(NetworkStatsService.TAG, "subtype changed for sub(" + mSubId + "): "
+                        + mLastCollapsedRatType + " -> " + collapsedRatType);
+            }
+            mLastCollapsedRatType = collapsedRatType;
+            mMonitor.mDelegate.onCollapsedRatTypeChanged(mSubscriberId, mLastCollapsedRatType);
+        }
+    }
+}
diff --git a/services/core/jni/com_android_server_net_NetworkStatsFactory.cpp b/services/core/jni/com_android_server_net_NetworkStatsFactory.cpp
index 9cd743b..8b6526f 100644
--- a/services/core/jni/com_android_server_net_NetworkStatsFactory.cpp
+++ b/services/core/jni/com_android_server_net_NetworkStatsFactory.cpp
@@ -20,6 +20,7 @@
 #include <inttypes.h>
 #include <sys/stat.h>
 #include <sys/types.h>
+#include <vector>
 
 #include <jni.h>
 
diff --git a/services/core/jni/com_android_server_net_NetworkStatsService.cpp b/services/core/jni/com_android_server_net_NetworkStatsService.cpp
index 4d4a7b4..0275f3e 100644
--- a/services/core/jni/com_android_server_net_NetworkStatsService.cpp
+++ b/services/core/jni/com_android_server_net_NetworkStatsService.cpp
@@ -33,7 +33,6 @@
 #include "bpf/BpfUtils.h"
 #include "netdbpf/BpfNetworkStats.h"
 
-using android::bpf::Stats;
 using android::bpf::bpfGetUidStats;
 using android::bpf::bpfGetIfaceStats;
 
@@ -54,7 +53,7 @@
     TCP_TX_PACKETS = 5
 };
 
-static uint64_t getStatsType(struct Stats* stats, StatsType type) {
+static uint64_t getStatsType(Stats* stats, StatsType type) {
     switch (type) {
         case RX_BYTES:
             return stats->rxBytes;
@@ -73,7 +72,7 @@
     }
 }
 
-static int parseIfaceStats(const char* iface, struct Stats* stats) {
+static int parseIfaceStats(const char* iface, Stats* stats) {
     FILE *fp = fopen(QTAGUID_IFACE_STATS, "r");
     if (fp == NULL) {
         return -1;
@@ -117,7 +116,7 @@
     return 0;
 }
 
-static int parseUidStats(const uint32_t uid, struct Stats* stats) {
+static int parseUidStats(const uint32_t uid, Stats* stats) {
     FILE *fp = fopen(QTAGUID_UID_STATS, "r");
     if (fp == NULL) {
         return -1;
@@ -150,8 +149,7 @@
 }
 
 static jlong getTotalStat(JNIEnv* env, jclass clazz, jint type, jboolean useBpfStats) {
-    struct Stats stats;
-    memset(&stats, 0, sizeof(Stats));
+    Stats stats = {};
 
     if (useBpfStats) {
         if (bpfGetIfaceStats(NULL, &stats) == 0) {
@@ -175,8 +173,7 @@
         return UNKNOWN;
     }
 
-    struct Stats stats;
-    memset(&stats, 0, sizeof(Stats));
+    Stats stats = {};
 
     if (useBpfStats) {
         if (bpfGetIfaceStats(iface8.c_str(), &stats) == 0) {
@@ -194,8 +191,7 @@
 }
 
 static jlong getUidStat(JNIEnv* env, jclass clazz, jint uid, jint type, jboolean useBpfStats) {
-    struct Stats stats;
-    memset(&stats, 0, sizeof(Stats));
+    Stats stats = {};
 
     if (useBpfStats) {
         if (bpfGetUidStats(uid, &stats) == 0) {