android-35/android/net/netstats/NetworkStatsDataMigrationUtils.java - platform/prebuilts/fullsdk/sources - Git at Google

 /*
  * Copyright (C) 2022 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;

 import static android.annotation.SystemApi.Client.MODULE_LIBRARIES;
 import static android.net.ConnectivityManager.TYPE_MOBILE;
 import static android.net.ConnectivityManager.TYPE_MOBILE_DUN;
 import static android.net.ConnectivityManager.TYPE_MOBILE_HIPRI;
 import static android.net.ConnectivityManager.TYPE_MOBILE_MMS;
 import static android.net.ConnectivityManager.TYPE_MOBILE_SUPL;
 import static android.net.NetworkStats.SET_DEFAULT;
 import static android.net.NetworkStats.TAG_NONE;
 import static android.telephony.SubscriptionManager.INVALID_SUBSCRIPTION_ID;

 import android.annotation.NonNull;
 import android.annotation.StringDef;
 import android.annotation.SystemApi;
 import android.net.NetworkIdentity;
 import android.net.NetworkStatsCollection;
 import android.net.NetworkStatsHistory;
 import android.net.NetworkTemplate;
 import android.os.Environment;
 import android.util.AtomicFile;

 import com.android.internal.annotations.VisibleForTesting;
 import com.android.internal.util.ArtFastDataInput;

 import libcore.io.IoUtils;

 import java.io.BufferedInputStream;
 import java.io.DataInput;
 import java.io.DataInputStream;
 import java.io.File;
 import java.io.FileInputStream;
 import java.io.FileNotFoundException;
 import java.io.IOException;
 import java.lang.annotation.Retention;
 import java.lang.annotation.RetentionPolicy;
 import java.net.ProtocolException;
 import java.util.ArrayList;
 import java.util.Arrays;
 import java.util.HashSet;
 import java.util.Map;
 import java.util.Set;

 /**
  * Helper class to read old version of persistent network statistics.
  *
  * The implementation is intended to be modified by OEM partners to
  * accommodate their custom changes.
  *
  * @hide
  */
 @SystemApi(client = MODULE_LIBRARIES)
 public class NetworkStatsDataMigrationUtils {
     /**
      * Prefix of the files which are used to store per network interface statistics.
      */
     public static final String PREFIX_XT = "xt";
     /**
      * Prefix of the files which are used to store per uid statistics.
      */
     public static final String PREFIX_UID = "uid";
     /**
      * Prefix of the files which are used to store per uid tagged traffic statistics.
      */
     public static final String PREFIX_UID_TAG = "uid_tag";

     /** @hide */
     @StringDef(prefix = {"PREFIX_"}, value = {
         PREFIX_XT,
         PREFIX_UID,
         PREFIX_UID_TAG,
     })
     @Retention(RetentionPolicy.SOURCE)
     public @interface Prefix {}

     private static final Map<String, String> sPrefixLegacyFileNameMap = Map.of(
             PREFIX_XT, "netstats_xt.bin",
             PREFIX_UID, "netstats_uid.bin",
             PREFIX_UID_TAG, "netstats_uid.bin");

     // These version constants are copied from NetworkStatsCollection/History, which is okay for
     // OEMs to modify to adapt their own logic.
     private static class CollectionVersion {
         static final int VERSION_NETWORK_INIT = 1;

         static final int VERSION_UID_INIT = 1;
         static final int VERSION_UID_WITH_IDENT = 2;
         static final int VERSION_UID_WITH_TAG = 3;
         static final int VERSION_UID_WITH_SET = 4;

         static final int VERSION_UNIFIED_INIT = 16;
     }

     private static class HistoryVersion {
         static final int VERSION_INIT = 1;
         static final int VERSION_ADD_PACKETS = 2;
         static final int VERSION_ADD_ACTIVE = 3;
     }

     private static class IdentitySetVersion {
         static final int VERSION_INIT = 1;
         static final int VERSION_ADD_ROAMING = 2;
         static final int VERSION_ADD_NETWORK_ID = 3;
         static final int VERSION_ADD_METERED = 4;
         static final int VERSION_ADD_DEFAULT_NETWORK = 5;
         static final int VERSION_ADD_OEM_MANAGED_NETWORK = 6;
         static final int VERSION_ADD_SUB_ID = 7;
     }

     /**
      * File header magic number: "ANET". The definition is copied from NetworkStatsCollection,
      * but it is fine for OEM to re-define to their own value to adapt the legacy file reading
      * logic.
      */
     private static final int FILE_MAGIC = 0x414E4554;
     /** Default buffer size from BufferedInputStream */
     private static final int BUFFER_SIZE = 8192;

     // Constructing this object is not allowed.
     private NetworkStatsDataMigrationUtils() {
     }

     // Used to read files at /data/system/netstats_*.bin.
     @NonNull
     private static File getPlatformSystemDir() {
         return new File(Environment.getDataDirectory(), "system");
     }

     // Used to read files at /data/system/netstats/<tag>.<start>-<end>.
     @NonNull
     private static File getPlatformBaseDir() {
         File baseDir = new File(getPlatformSystemDir(), "netstats");
         baseDir.mkdirs();
         return baseDir;
     }

     // Get /data/system/netstats_*.bin legacy files. Does not check for existence.
     @NonNull
     private static File getLegacyBinFileForPrefix(@NonNull @Prefix String prefix) {
         return new File(getPlatformSystemDir(), sPrefixLegacyFileNameMap.get(prefix));
     }

     // List /data/system/netstats/[xt|uid|uid_tag].<start>-<end> legacy files.
     @NonNull
     private static ArrayList<File> getPlatformFileListForPrefix(@NonNull @Prefix String prefix) {
         final ArrayList<File> list = new ArrayList<>();
         final File platformFiles = getPlatformBaseDir();
         if (platformFiles.exists()) {
             final String[] files = platformFiles.list();
             if (files == null) return list;
             Arrays.sort(files);
             for (String name : files) {
                 // Skip when prefix doesn't match.
                 if (!name.startsWith(prefix + ".")) continue;

                 list.add(new File(platformFiles, name));
             }
         }
         return list;
     }

     /**
      * Read legacy persisted network stats from disk.
      *
      * This function provides the implementation to read legacy network stats
      * from disk. It is used for migration of legacy network stats into the
      * stats provided by the Connectivity module.
      * This function needs to know about the previous format(s) of the network
      * stats data that might be stored on this device so it can be read and
      * conserved upon upgrade to Android 13 or above.
      *
      * This function will be called multiple times sequentially, all on the
      * same thread, and will not be called multiple times concurrently. This
      * function is expected to do a substantial amount of disk access, and
      * doesn't need to return particularly fast, but the first boot after
      * an upgrade to Android 13+ will be held until migration is done. As
      * migration is only necessary once, after the first boot following the
      * upgrade, this delay is not incurred.
      *
      * If this function fails in any way, it should throw an exception. If this
      * happens, the system can't know about the data that was stored in the
      * legacy files, but it will still count data usage happening on this
      * session. On the next boot, the system will try migration again, and
      * merge the returned data with the data used with the previous session.
      * The system will only try the migration up to three (3) times. The remaining
      * count is stored in the netstats_import_legacy_file_needed device config. The
      * legacy data is never deleted by the mainline module to avoid any possible
      * data loss.
      *
      * It is possible to set the netstats_import_legacy_file_needed device config
      * to any positive integer to force the module to perform the migration. This
      * can be achieved by calling the following command before rebooting :
      *     adb shell device_config put connectivity netstats_import_legacy_file_needed 1
      *
      * The AOSP implementation provides code to read persisted network stats as
      * they were written by AOSP prior to Android 13.
      * OEMs who have used the AOSP implementation of persisting network stats
      * to disk don't need to change anything.
      * OEM that had modifications to this format should modify this function
      * to read from their custom file format or locations if necessary.
      *
      * @param prefix         Type of data which is being read by the service.
      * @param bucketDuration Duration of the buckets of the object, in milliseconds.
      * @return {@link NetworkStatsCollection} instance.
      */
     @NonNull
     public static NetworkStatsCollection readPlatformCollection(
             @NonNull @Prefix String prefix, long bucketDuration) throws IOException {
         final NetworkStatsCollection.Builder builder =
                 new NetworkStatsCollection.Builder(bucketDuration);

         // Import /data/system/netstats_uid.bin legacy files if exists.
         switch (prefix) {
             case PREFIX_UID:
             case PREFIX_UID_TAG:
                 final File uidFile = getLegacyBinFileForPrefix(prefix);
                 if (uidFile.exists()) {
                     readLegacyUid(builder, uidFile, PREFIX_UID_TAG.equals(prefix) ? true : false);
                 }
                 break;
             default:
                 // Ignore other types.
         }

         // Import /data/system/netstats/[xt|uid|uid_tag].<start>-<end> legacy files if exists.
         final ArrayList<File> platformFiles = getPlatformFileListForPrefix(prefix);
         for (final File platformFile : platformFiles) {
             if (platformFile.exists()) {
                 readPlatformCollection(builder, platformFile);
             }
         }

         return builder.build();
     }

     private static void readPlatformCollection(@NonNull NetworkStatsCollection.Builder builder,
             @NonNull File file) throws IOException {
         final FileInputStream is = new FileInputStream(file);
         final ArtFastDataInput dataIn = new ArtFastDataInput(is, BUFFER_SIZE);
         try {
             readPlatformCollection(builder, dataIn);
         } finally {
             IoUtils.closeQuietly(dataIn);
         }
     }

     /**
      * Helper function to read old version of NetworkStatsCollections that resided in the platform.
      *
      * @hide
      */
     @VisibleForTesting
     public static void readPlatformCollection(@NonNull NetworkStatsCollection.Builder builder,
             @NonNull DataInput in) throws IOException {
         // verify file magic header intact
         final int magic = in.readInt();
         if (magic != FILE_MAGIC) {
             throw new ProtocolException("unexpected magic: " + magic);
         }

         final int version = in.readInt();
         switch (version) {
             case CollectionVersion.VERSION_UNIFIED_INIT: {
                 // uid := size *(NetworkIdentitySet size *(uid set tag NetworkStatsHistory))
                 final int identSize = in.readInt();
                 for (int i = 0; i < identSize; i++) {
                     final Set<NetworkIdentity> ident = readPlatformNetworkIdentitySet(in);

                     final int size = in.readInt();
                     for (int j = 0; j < size; j++) {
                         final int uid = in.readInt();
                         final int set = in.readInt();
                         final int tag = in.readInt();

                         final NetworkStatsCollection.Key key = new NetworkStatsCollection.Key(
                                 ident, uid, set, tag);
                         final NetworkStatsHistory history = readPlatformHistory(in);
                         builder.addEntry(key, history);
                     }
                 }
                 break;
             }
             default: {
                 throw new ProtocolException("unexpected version: " + version);
             }
         }
     }

     // Copied from NetworkStatsHistory#DataStreamUtils.
     private static long[] readFullLongArray(DataInput in) throws IOException {
         final int size = in.readInt();
         if (size < 0) throw new ProtocolException("negative array size");
         final long[] values = new long[size];
         for (int i = 0; i < values.length; i++) {
             values[i] = in.readLong();
         }
         return values;
     }

     // Copied from NetworkStatsHistory#DataStreamUtils.
     private static long[] readVarLongArray(@NonNull DataInput in) throws IOException {
         final int size = in.readInt();
         if (size == -1) return null;
         if (size < 0) throw new ProtocolException("negative array size");
         final long[] values = new long[size];
         for (int i = 0; i < values.length; i++) {
             values[i] = readVarLong(in);
         }
         return values;
     }

     /**
      * Read variable-length {@link Long} using protobuf-style approach.
      */
     // Copied from NetworkStatsHistory#DataStreamUtils.
     private static long readVarLong(DataInput in) throws IOException {
         int shift = 0;
         long result = 0;
         while (shift < 64) {
             byte b = in.readByte();
             result |= (long) (b & 0x7F) << shift;
             if ((b & 0x80) == 0) {
                 return result;
             }
             shift += 7;
         }
         throw new ProtocolException("malformed var long");
     }

     // Copied from NetworkIdentitySet.
     private static String readOptionalString(DataInput in) throws IOException {
         if (in.readByte() != 0) {
             return in.readUTF();
         } else {
             return null;
         }
     }

     /**
      * This is copied from NetworkStatsHistory#NetworkStatsHistory(DataInput in). But it is fine
      * for OEM to re-write the logic to adapt the legacy file reading.
      */
     @NonNull
     private static NetworkStatsHistory readPlatformHistory(@NonNull DataInput in)
             throws IOException {
         final long bucketDuration;
         final long[] bucketStart;
         final long[] rxBytes;
         final long[] rxPackets;
         final long[] txBytes;
         final long[] txPackets;
         final long[] operations;
         final int bucketCount;
         long[] activeTime = new long[0];

         final int version = in.readInt();
         switch (version) {
             case HistoryVersion.VERSION_INIT: {
                 bucketDuration = in.readLong();
                 bucketStart = readFullLongArray(in);
                 rxBytes = readFullLongArray(in);
                 rxPackets = new long[bucketStart.length];
                 txBytes = readFullLongArray(in);
                 txPackets = new long[bucketStart.length];
                 operations = new long[bucketStart.length];
                 bucketCount = bucketStart.length;
                 break;
             }
             case HistoryVersion.VERSION_ADD_PACKETS:
             case HistoryVersion.VERSION_ADD_ACTIVE: {
                 bucketDuration = in.readLong();
                 bucketStart = readVarLongArray(in);
                 activeTime = (version >= HistoryVersion.VERSION_ADD_ACTIVE)
                         ? readVarLongArray(in)
                         : new long[bucketStart.length];
                 rxBytes = readVarLongArray(in);
                 rxPackets = readVarLongArray(in);
                 txBytes = readVarLongArray(in);
                 txPackets = readVarLongArray(in);
                 operations = readVarLongArray(in);
                 bucketCount = bucketStart.length;
                 break;
             }
             default: {
                 throw new ProtocolException("unexpected version: " + version);
             }
         }

         final NetworkStatsHistory.Builder historyBuilder =
                 new NetworkStatsHistory.Builder(bucketDuration, bucketCount);
         for (int i = 0; i < bucketCount; i++) {
             final NetworkStatsHistory.Entry entry = new NetworkStatsHistory.Entry(
                     bucketStart[i], activeTime[i],
                     rxBytes[i], rxPackets[i], txBytes[i], txPackets[i], operations[i]);
             historyBuilder.addEntry(entry);
         }

         return historyBuilder.build();
     }

     @NonNull
     private static Set<NetworkIdentity> readPlatformNetworkIdentitySet(@NonNull DataInput in)
             throws IOException {
         final int version = in.readInt();
         final int size = in.readInt();
         final Set<NetworkIdentity> set = new HashSet<>();
         for (int i = 0; i < size; i++) {
             if (version <= IdentitySetVersion.VERSION_INIT) {
                 final int ignored = in.readInt();
             }
             final int type = in.readInt();
             final int ratType = in.readInt();
             final String subscriberId = readOptionalString(in);
             final String networkId;
             if (version >= IdentitySetVersion.VERSION_ADD_NETWORK_ID) {
                 networkId = readOptionalString(in);
             } else {
                 networkId = null;
             }
             final boolean roaming;
             if (version >= IdentitySetVersion.VERSION_ADD_ROAMING) {
                 roaming = in.readBoolean();
             } else {
                 roaming = false;
             }

             final boolean metered;
             if (version >= IdentitySetVersion.VERSION_ADD_METERED) {
                 metered = in.readBoolean();
             } else {
                 // If this is the old data and the type is mobile, treat it as metered. (Note that
                 // if this is a mobile network, TYPE_MOBILE is the only possible type that could be
                 // used.)
                 metered = (type == TYPE_MOBILE);
             }

             final boolean defaultNetwork;
             if (version >= IdentitySetVersion.VERSION_ADD_DEFAULT_NETWORK) {
                 defaultNetwork = in.readBoolean();
             } else {
                 defaultNetwork = true;
             }

             final int oemNetCapabilities;
             if (version >= IdentitySetVersion.VERSION_ADD_OEM_MANAGED_NETWORK) {
                 oemNetCapabilities = in.readInt();
             } else {
                 oemNetCapabilities = NetworkTemplate.OEM_MANAGED_NO;
             }

             final int subId;
             if (version >= IdentitySetVersion.VERSION_ADD_SUB_ID) {
                 subId = in.readInt();
             } else {
                 subId = INVALID_SUBSCRIPTION_ID;
             }

             // Legacy files might contain TYPE_MOBILE_* types which were deprecated in later
             // releases. For backward compatibility, record them as TYPE_MOBILE instead.
             final int collapsedLegacyType = getCollapsedLegacyType(type);
             final NetworkIdentity.Builder builder = new NetworkIdentity.Builder()
                     .setType(collapsedLegacyType)
                     .setSubscriberId(subscriberId)
                     .setWifiNetworkKey(networkId)
                     .setRoaming(roaming).setMetered(metered)
                     .setDefaultNetwork(defaultNetwork)
                     .setOemManaged(oemNetCapabilities)
                     .setSubId(subId);
             if (type == TYPE_MOBILE && ratType != NetworkTemplate.NETWORK_TYPE_ALL) {
                 builder.setRatType(ratType);
             }
             set.add(builder.build());
         }
         return set;
     }

     private static int getCollapsedLegacyType(int networkType) {
         // The constants are referenced from ConnectivityManager#TYPE_MOBILE_*.
         switch (networkType) {
             case TYPE_MOBILE:
             case TYPE_MOBILE_SUPL:
             case TYPE_MOBILE_MMS:
             case TYPE_MOBILE_DUN:
             case TYPE_MOBILE_HIPRI:
             case 10 /* TYPE_MOBILE_FOTA */:
             case 11 /* TYPE_MOBILE_IMS */:
             case 12 /* TYPE_MOBILE_CBS */:
             case 14 /* TYPE_MOBILE_IA */:
             case 15 /* TYPE_MOBILE_EMERGENCY */:
                 return TYPE_MOBILE;
         }
         return networkType;
     }

     private static void readLegacyUid(@NonNull NetworkStatsCollection.Builder builder,
             @NonNull File uidFile, boolean onlyTaggedData) throws IOException {
         final AtomicFile inputFile = new AtomicFile(uidFile);
         DataInputStream in = new DataInputStream(new BufferedInputStream(inputFile.openRead()));
         try {
             readLegacyUid(builder, in, onlyTaggedData);
         } finally {
             IoUtils.closeQuietly(in);
         }
     }

     /**
      * Read legacy Uid statistics file format into the collection.
      *
      * This is copied from {@code NetworkStatsCollection#readLegacyUid}.
      * See {@code NetworkStatsService#maybeUpgradeLegacyStatsLocked}.
      *
      * @param taggedData whether to read only tagged data (true) or only non-tagged data
      *                   (false). For legacy uid files, the tagged data was stored in
      *                   the same binary file with non-tagged data. But in later releases,
      *                   these data should be kept in different recorders.
      * @hide
      */
     @VisibleForTesting
     public static void readLegacyUid(@NonNull NetworkStatsCollection.Builder builder,
             @NonNull DataInput in, boolean taggedData) throws IOException {
         try {
             // verify file magic header intact
             final int magic = in.readInt();
             if (magic != FILE_MAGIC) {
                 throw new ProtocolException("unexpected magic: " + magic);
             }

             final int version = in.readInt();
             switch (version) {
                 case CollectionVersion.VERSION_UID_INIT: {
                     // uid := size *(UID NetworkStatsHistory)
                     // drop this data version, since we don't have a good
                     // mapping into NetworkIdentitySet.
                     break;
                 }
                 case CollectionVersion.VERSION_UID_WITH_IDENT: {
                     // uid := size *(NetworkIdentitySet size *(UID NetworkStatsHistory))
                     // drop this data version, since this version only existed
                     // for a short time.
                     break;
                 }
                 case CollectionVersion.VERSION_UID_WITH_TAG:
                 case CollectionVersion.VERSION_UID_WITH_SET: {
                     // uid := size *(NetworkIdentitySet size *(uid set tag NetworkStatsHistory))
                     final int identSize = in.readInt();
                     for (int i = 0; i < identSize; i++) {
                         final Set<NetworkIdentity> ident = readPlatformNetworkIdentitySet(in);

                         final int size = in.readInt();
                         for (int j = 0; j < size; j++) {
                             final int uid = in.readInt();
                             final int set = (version >= CollectionVersion.VERSION_UID_WITH_SET)
                                     ? in.readInt()
                                     : SET_DEFAULT;
                             final int tag = in.readInt();

                             final NetworkStatsCollection.Key key = new NetworkStatsCollection.Key(
                                     ident, uid, set, tag);
                             final NetworkStatsHistory history = readPlatformHistory(in);

                             if ((tag == TAG_NONE) != taggedData) {
                                 builder.addEntry(key, history);
                             }
                         }
                     }
                     break;
                 }
                 default: {
                     throw new ProtocolException("unknown version: " + version);
                 }
             }
         } catch (FileNotFoundException | ProtocolException e) {
             // missing stats is okay, probably first boot
         }
     }
 }
	/*
	* Copyright (C) 2022 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;

	import static android.annotation.SystemApi.Client.MODULE_LIBRARIES;
	import static android.net.ConnectivityManager.TYPE_MOBILE;
	import static android.net.ConnectivityManager.TYPE_MOBILE_DUN;
	import static android.net.ConnectivityManager.TYPE_MOBILE_HIPRI;
	import static android.net.ConnectivityManager.TYPE_MOBILE_MMS;
	import static android.net.ConnectivityManager.TYPE_MOBILE_SUPL;
	import static android.net.NetworkStats.SET_DEFAULT;
	import static android.net.NetworkStats.TAG_NONE;
	import static android.telephony.SubscriptionManager.INVALID_SUBSCRIPTION_ID;

	import android.annotation.NonNull;
	import android.annotation.StringDef;
	import android.annotation.SystemApi;
	import android.net.NetworkIdentity;
	import android.net.NetworkStatsCollection;
	import android.net.NetworkStatsHistory;
	import android.net.NetworkTemplate;
	import android.os.Environment;
	import android.util.AtomicFile;

	import com.android.internal.annotations.VisibleForTesting;
	import com.android.internal.util.ArtFastDataInput;

	import libcore.io.IoUtils;

	import java.io.BufferedInputStream;
	import java.io.DataInput;
	import java.io.DataInputStream;
	import java.io.File;
	import java.io.FileInputStream;
	import java.io.FileNotFoundException;
	import java.io.IOException;
	import java.lang.annotation.Retention;
	import java.lang.annotation.RetentionPolicy;
	import java.net.ProtocolException;
	import java.util.ArrayList;
	import java.util.Arrays;
	import java.util.HashSet;
	import java.util.Map;
	import java.util.Set;

	/**
	* Helper class to read old version of persistent network statistics.
	*
	* The implementation is intended to be modified by OEM partners to
	* accommodate their custom changes.
	*
	* @hide
	*/
	@SystemApi(client = MODULE_LIBRARIES)
	public class NetworkStatsDataMigrationUtils {
	/**
	* Prefix of the files which are used to store per network interface statistics.
	*/
	public static final String PREFIX_XT = "xt";
	/**
	* Prefix of the files which are used to store per uid statistics.
	*/
	public static final String PREFIX_UID = "uid";
	/**
	* Prefix of the files which are used to store per uid tagged traffic statistics.
	*/
	public static final String PREFIX_UID_TAG = "uid_tag";

	/** @hide */
	@StringDef(prefix = {"PREFIX_"}, value = {
	PREFIX_XT,
	PREFIX_UID,
	PREFIX_UID_TAG,
	})
	@Retention(RetentionPolicy.SOURCE)
	public @interface Prefix {}

	private static final Map<String, String> sPrefixLegacyFileNameMap = Map.of(
	PREFIX_XT, "netstats_xt.bin",
	PREFIX_UID, "netstats_uid.bin",
	PREFIX_UID_TAG, "netstats_uid.bin");

	// These version constants are copied from NetworkStatsCollection/History, which is okay for
	// OEMs to modify to adapt their own logic.
	private static class CollectionVersion {
	static final int VERSION_NETWORK_INIT = 1;

	static final int VERSION_UID_INIT = 1;
	static final int VERSION_UID_WITH_IDENT = 2;
	static final int VERSION_UID_WITH_TAG = 3;
	static final int VERSION_UID_WITH_SET = 4;

	static final int VERSION_UNIFIED_INIT = 16;
	}

	private static class HistoryVersion {
	static final int VERSION_INIT = 1;
	static final int VERSION_ADD_PACKETS = 2;
	static final int VERSION_ADD_ACTIVE = 3;
	}

	private static class IdentitySetVersion {
	static final int VERSION_INIT = 1;
	static final int VERSION_ADD_ROAMING = 2;
	static final int VERSION_ADD_NETWORK_ID = 3;
	static final int VERSION_ADD_METERED = 4;
	static final int VERSION_ADD_DEFAULT_NETWORK = 5;
	static final int VERSION_ADD_OEM_MANAGED_NETWORK = 6;
	static final int VERSION_ADD_SUB_ID = 7;
	}

	/**
	* File header magic number: "ANET". The definition is copied from NetworkStatsCollection,
	* but it is fine for OEM to re-define to their own value to adapt the legacy file reading
	* logic.
	*/
	private static final int FILE_MAGIC = 0x414E4554;
	/** Default buffer size from BufferedInputStream */
	private static final int BUFFER_SIZE = 8192;

	// Constructing this object is not allowed.
	private NetworkStatsDataMigrationUtils() {
	}

	// Used to read files at /data/system/netstats_*.bin.
	@NonNull
	private static File getPlatformSystemDir() {
	return new File(Environment.getDataDirectory(), "system");
	}

	// Used to read files at /data/system/netstats/<tag>.<start>-<end>.
	@NonNull
	private static File getPlatformBaseDir() {
	File baseDir = new File(getPlatformSystemDir(), "netstats");
	baseDir.mkdirs();
	return baseDir;
	}

	// Get /data/system/netstats_*.bin legacy files. Does not check for existence.
	@NonNull
	private static File getLegacyBinFileForPrefix(@NonNull @Prefix String prefix) {
	return new File(getPlatformSystemDir(), sPrefixLegacyFileNameMap.get(prefix));
	}

	// List /data/system/netstats/[xt\|uid\|uid_tag].<start>-<end> legacy files.
	@NonNull
	private static ArrayList<File> getPlatformFileListForPrefix(@NonNull @Prefix String prefix) {
	final ArrayList<File> list = new ArrayList<>();
	final File platformFiles = getPlatformBaseDir();
	if (platformFiles.exists()) {
	final String[] files = platformFiles.list();
	if (files == null) return list;
	Arrays.sort(files);
	for (String name : files) {
	// Skip when prefix doesn't match.
	if (!name.startsWith(prefix + ".")) continue;

	list.add(new File(platformFiles, name));
	}
	}
	return list;
	}

	/**
	* Read legacy persisted network stats from disk.
	*
	* This function provides the implementation to read legacy network stats
	* from disk. It is used for migration of legacy network stats into the
	* stats provided by the Connectivity module.
	* This function needs to know about the previous format(s) of the network
	* stats data that might be stored on this device so it can be read and
	* conserved upon upgrade to Android 13 or above.
	*
	* This function will be called multiple times sequentially, all on the
	* same thread, and will not be called multiple times concurrently. This
	* function is expected to do a substantial amount of disk access, and
	* doesn't need to return particularly fast, but the first boot after
	* an upgrade to Android 13+ will be held until migration is done. As
	* migration is only necessary once, after the first boot following the
	* upgrade, this delay is not incurred.
	*
	* If this function fails in any way, it should throw an exception. If this
	* happens, the system can't know about the data that was stored in the
	* legacy files, but it will still count data usage happening on this
	* session. On the next boot, the system will try migration again, and
	* merge the returned data with the data used with the previous session.
	* The system will only try the migration up to three (3) times. The remaining
	* count is stored in the netstats_import_legacy_file_needed device config. The
	* legacy data is never deleted by the mainline module to avoid any possible
	* data loss.
	*
	* It is possible to set the netstats_import_legacy_file_needed device config
	* to any positive integer to force the module to perform the migration. This
	* can be achieved by calling the following command before rebooting :
	* adb shell device_config put connectivity netstats_import_legacy_file_needed 1
	*
	* The AOSP implementation provides code to read persisted network stats as
	* they were written by AOSP prior to Android 13.
	* OEMs who have used the AOSP implementation of persisting network stats
	* to disk don't need to change anything.
	* OEM that had modifications to this format should modify this function
	* to read from their custom file format or locations if necessary.
	*
	* @param prefix Type of data which is being read by the service.
	* @param bucketDuration Duration of the buckets of the object, in milliseconds.
	* @return {@link NetworkStatsCollection} instance.
	*/
	@NonNull
	public static NetworkStatsCollection readPlatformCollection(
	@NonNull @Prefix String prefix, long bucketDuration) throws IOException {
	final NetworkStatsCollection.Builder builder =
	new NetworkStatsCollection.Builder(bucketDuration);

	// Import /data/system/netstats_uid.bin legacy files if exists.
	switch (prefix) {
	case PREFIX_UID:
	case PREFIX_UID_TAG:
	final File uidFile = getLegacyBinFileForPrefix(prefix);
	if (uidFile.exists()) {
	readLegacyUid(builder, uidFile, PREFIX_UID_TAG.equals(prefix) ? true : false);
	}
	break;
	default:
	// Ignore other types.
	}

	// Import /data/system/netstats/[xt\|uid\|uid_tag].<start>-<end> legacy files if exists.
	final ArrayList<File> platformFiles = getPlatformFileListForPrefix(prefix);
	for (final File platformFile : platformFiles) {
	if (platformFile.exists()) {
	readPlatformCollection(builder, platformFile);
	}
	}

	return builder.build();
	}

	private static void readPlatformCollection(@NonNull NetworkStatsCollection.Builder builder,
	@NonNull File file) throws IOException {
	final FileInputStream is = new FileInputStream(file);
	final ArtFastDataInput dataIn = new ArtFastDataInput(is, BUFFER_SIZE);
	try {
	readPlatformCollection(builder, dataIn);
	} finally {
	IoUtils.closeQuietly(dataIn);
	}
	}

	/**
	* Helper function to read old version of NetworkStatsCollections that resided in the platform.
	*
	* @hide
	*/
	@VisibleForTesting
	public static void readPlatformCollection(@NonNull NetworkStatsCollection.Builder builder,
	@NonNull DataInput in) throws IOException {
	// verify file magic header intact
	final int magic = in.readInt();
	if (magic != FILE_MAGIC) {
	throw new ProtocolException("unexpected magic: " + magic);
	}

	final int version = in.readInt();
	switch (version) {
	case CollectionVersion.VERSION_UNIFIED_INIT: {
	// uid := size (NetworkIdentitySet size (uid set tag NetworkStatsHistory))
	final int identSize = in.readInt();
	for (int i = 0; i < identSize; i++) {
	final Set<NetworkIdentity> ident = readPlatformNetworkIdentitySet(in);

	final int size = in.readInt();
	for (int j = 0; j < size; j++) {
	final int uid = in.readInt();
	final int set = in.readInt();
	final int tag = in.readInt();

	final NetworkStatsCollection.Key key = new NetworkStatsCollection.Key(
	ident, uid, set, tag);
	final NetworkStatsHistory history = readPlatformHistory(in);
	builder.addEntry(key, history);
	}
	}
	break;
	}
	default: {
	throw new ProtocolException("unexpected version: " + version);
	}
	}
	}

	// Copied from NetworkStatsHistory#DataStreamUtils.
	private static long[] readFullLongArray(DataInput in) throws IOException {
	final int size = in.readInt();
	if (size < 0) throw new ProtocolException("negative array size");
	final long[] values = new long[size];
	for (int i = 0; i < values.length; i++) {
	values[i] = in.readLong();
	}
	return values;
	}

	// Copied from NetworkStatsHistory#DataStreamUtils.
	private static long[] readVarLongArray(@NonNull DataInput in) throws IOException {
	final int size = in.readInt();
	if (size == -1) return null;
	if (size < 0) throw new ProtocolException("negative array size");
	final long[] values = new long[size];
	for (int i = 0; i < values.length; i++) {
	values[i] = readVarLong(in);
	}
	return values;
	}

	/**
	* Read variable-length {@link Long} using protobuf-style approach.
	*/
	// Copied from NetworkStatsHistory#DataStreamUtils.
	private static long readVarLong(DataInput in) throws IOException {
	int shift = 0;
	long result = 0;
	while (shift < 64) {
	byte b = in.readByte();
	result \|= (long) (b & 0x7F) << shift;
	if ((b & 0x80) == 0) {
	return result;
	}
	shift += 7;
	}
	throw new ProtocolException("malformed var long");
	}

	// Copied from NetworkIdentitySet.
	private static String readOptionalString(DataInput in) throws IOException {
	if (in.readByte() != 0) {
	return in.readUTF();
	} else {
	return null;
	}
	}

	/**
	* This is copied from NetworkStatsHistory#NetworkStatsHistory(DataInput in). But it is fine
	* for OEM to re-write the logic to adapt the legacy file reading.
	*/
	@NonNull
	private static NetworkStatsHistory readPlatformHistory(@NonNull DataInput in)
	throws IOException {
	final long bucketDuration;
	final long[] bucketStart;
	final long[] rxBytes;
	final long[] rxPackets;
	final long[] txBytes;
	final long[] txPackets;
	final long[] operations;
	final int bucketCount;
	long[] activeTime = new long[0];

	final int version = in.readInt();
	switch (version) {
	case HistoryVersion.VERSION_INIT: {
	bucketDuration = in.readLong();
	bucketStart = readFullLongArray(in);
	rxBytes = readFullLongArray(in);
	rxPackets = new long[bucketStart.length];
	txBytes = readFullLongArray(in);
	txPackets = new long[bucketStart.length];
	operations = new long[bucketStart.length];
	bucketCount = bucketStart.length;
	break;
	}
	case HistoryVersion.VERSION_ADD_PACKETS:
	case HistoryVersion.VERSION_ADD_ACTIVE: {
	bucketDuration = in.readLong();
	bucketStart = readVarLongArray(in);
	activeTime = (version >= HistoryVersion.VERSION_ADD_ACTIVE)
	? readVarLongArray(in)
	: new long[bucketStart.length];
	rxBytes = readVarLongArray(in);
	rxPackets = readVarLongArray(in);
	txBytes = readVarLongArray(in);
	txPackets = readVarLongArray(in);
	operations = readVarLongArray(in);
	bucketCount = bucketStart.length;
	break;
	}
	default: {
	throw new ProtocolException("unexpected version: " + version);
	}
	}

	final NetworkStatsHistory.Builder historyBuilder =
	new NetworkStatsHistory.Builder(bucketDuration, bucketCount);
	for (int i = 0; i < bucketCount; i++) {
	final NetworkStatsHistory.Entry entry = new NetworkStatsHistory.Entry(
	bucketStart[i], activeTime[i],
	rxBytes[i], rxPackets[i], txBytes[i], txPackets[i], operations[i]);
	historyBuilder.addEntry(entry);
	}

	return historyBuilder.build();
	}

	@NonNull
	private static Set<NetworkIdentity> readPlatformNetworkIdentitySet(@NonNull DataInput in)
	throws IOException {
	final int version = in.readInt();
	final int size = in.readInt();
	final Set<NetworkIdentity> set = new HashSet<>();
	for (int i = 0; i < size; i++) {
	if (version <= IdentitySetVersion.VERSION_INIT) {
	final int ignored = in.readInt();
	}
	final int type = in.readInt();
	final int ratType = in.readInt();
	final String subscriberId = readOptionalString(in);
	final String networkId;
	if (version >= IdentitySetVersion.VERSION_ADD_NETWORK_ID) {
	networkId = readOptionalString(in);
	} else {
	networkId = null;
	}
	final boolean roaming;
	if (version >= IdentitySetVersion.VERSION_ADD_ROAMING) {
	roaming = in.readBoolean();
	} else {
	roaming = false;
	}

	final boolean metered;
	if (version >= IdentitySetVersion.VERSION_ADD_METERED) {
	metered = in.readBoolean();
	} else {
	// If this is the old data and the type is mobile, treat it as metered. (Note that
	// if this is a mobile network, TYPE_MOBILE is the only possible type that could be
	// used.)
	metered = (type == TYPE_MOBILE);
	}

	final boolean defaultNetwork;
	if (version >= IdentitySetVersion.VERSION_ADD_DEFAULT_NETWORK) {
	defaultNetwork = in.readBoolean();
	} else {
	defaultNetwork = true;
	}

	final int oemNetCapabilities;
	if (version >= IdentitySetVersion.VERSION_ADD_OEM_MANAGED_NETWORK) {
	oemNetCapabilities = in.readInt();
	} else {
	oemNetCapabilities = NetworkTemplate.OEM_MANAGED_NO;
	}

	final int subId;
	if (version >= IdentitySetVersion.VERSION_ADD_SUB_ID) {
	subId = in.readInt();
	} else {
	subId = INVALID_SUBSCRIPTION_ID;
	}

	// Legacy files might contain TYPE_MOBILE_* types which were deprecated in later
	// releases. For backward compatibility, record them as TYPE_MOBILE instead.
	final int collapsedLegacyType = getCollapsedLegacyType(type);
	final NetworkIdentity.Builder builder = new NetworkIdentity.Builder()
	.setType(collapsedLegacyType)
	.setSubscriberId(subscriberId)
	.setWifiNetworkKey(networkId)
	.setRoaming(roaming).setMetered(metered)
	.setDefaultNetwork(defaultNetwork)
	.setOemManaged(oemNetCapabilities)
	.setSubId(subId);
	if (type == TYPE_MOBILE && ratType != NetworkTemplate.NETWORK_TYPE_ALL) {
	builder.setRatType(ratType);
	}
	set.add(builder.build());
	}
	return set;
	}

	private static int getCollapsedLegacyType(int networkType) {
	// The constants are referenced from ConnectivityManager#TYPE_MOBILE_*.
	switch (networkType) {
	case TYPE_MOBILE:
	case TYPE_MOBILE_SUPL:
	case TYPE_MOBILE_MMS:
	case TYPE_MOBILE_DUN:
	case TYPE_MOBILE_HIPRI:
	case 10 /* TYPE_MOBILE_FOTA */:
	case 11 /* TYPE_MOBILE_IMS */:
	case 12 /* TYPE_MOBILE_CBS */:
	case 14 /* TYPE_MOBILE_IA */:
	case 15 /* TYPE_MOBILE_EMERGENCY */:
	return TYPE_MOBILE;
	}
	return networkType;
	}

	private static void readLegacyUid(@NonNull NetworkStatsCollection.Builder builder,
	@NonNull File uidFile, boolean onlyTaggedData) throws IOException {
	final AtomicFile inputFile = new AtomicFile(uidFile);
	DataInputStream in = new DataInputStream(new BufferedInputStream(inputFile.openRead()));
	try {
	readLegacyUid(builder, in, onlyTaggedData);
	} finally {
	IoUtils.closeQuietly(in);
	}
	}

	/**
	* Read legacy Uid statistics file format into the collection.
	*
	* This is copied from {@code NetworkStatsCollection#readLegacyUid}.
	* See {@code NetworkStatsService#maybeUpgradeLegacyStatsLocked}.
	*
	* @param taggedData whether to read only tagged data (true) or only non-tagged data
	* (false). For legacy uid files, the tagged data was stored in
	* the same binary file with non-tagged data. But in later releases,
	* these data should be kept in different recorders.
	* @hide
	*/
	@VisibleForTesting
	public static void readLegacyUid(@NonNull NetworkStatsCollection.Builder builder,
	@NonNull DataInput in, boolean taggedData) throws IOException {
	try {
	// verify file magic header intact
	final int magic = in.readInt();
	if (magic != FILE_MAGIC) {
	throw new ProtocolException("unexpected magic: " + magic);
	}

	final int version = in.readInt();
	switch (version) {
	case CollectionVersion.VERSION_UID_INIT: {
	// uid := size *(UID NetworkStatsHistory)
	// drop this data version, since we don't have a good
	// mapping into NetworkIdentitySet.
	break;
	}
	case CollectionVersion.VERSION_UID_WITH_IDENT: {
	// uid := size (NetworkIdentitySet size (UID NetworkStatsHistory))
	// drop this data version, since this version only existed
	// for a short time.
	break;
	}
	case CollectionVersion.VERSION_UID_WITH_TAG:
	case CollectionVersion.VERSION_UID_WITH_SET: {
	// uid := size (NetworkIdentitySet size (uid set tag NetworkStatsHistory))
	final int identSize = in.readInt();
	for (int i = 0; i < identSize; i++) {
	final Set<NetworkIdentity> ident = readPlatformNetworkIdentitySet(in);

	final int size = in.readInt();
	for (int j = 0; j < size; j++) {
	final int uid = in.readInt();
	final int set = (version >= CollectionVersion.VERSION_UID_WITH_SET)
	? in.readInt()
	: SET_DEFAULT;
	final int tag = in.readInt();

	final NetworkStatsCollection.Key key = new NetworkStatsCollection.Key(
	ident, uid, set, tag);
	final NetworkStatsHistory history = readPlatformHistory(in);

	if ((tag == TAG_NONE) != taggedData) {
	builder.addEntry(key, history);
	}
	}
	}
	break;
	}
	default: {
	throw new ProtocolException("unknown version: " + version);
	}
	}
	} catch (FileNotFoundException \| ProtocolException e) {
	// missing stats is okay, probably first boot
	}
	}
	}