/*
 * Copyright (C) 2011 The Android Open Source Project
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package android.net;

import android.os.Parcel;
import android.os.Parcelable;
import android.os.SystemClock;
import android.util.Slog;
import android.util.SparseBooleanArray;

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

import libcore.util.EmptyArray;

import java.io.CharArrayWriter;
import java.io.PrintWriter;
import java.util.Arrays;
import java.util.HashSet;
import java.util.Map;
import java.util.Objects;

Collection of active network statistics. Can contain summary details across all interfaces, or details with per-UID granularity. Internally stores data as a large table, closely matching /proc/ data format. This structure optimizes for rapid in-memory comparison, but consider using NetworkStatsHistory when persisting. 
@hide
/**
 * Collection of active network statistics. Can contain summary details across
 * all interfaces, or details with per-UID granularity. Internally stores data
 * as a large table, closely matching {@code /proc/} data format. This structure
 * optimizes for rapid in-memory comparison, but consider using
 * {@link NetworkStatsHistory} when persisting.
 *
 * @hide
 */
public class NetworkStats implements Parcelable {
    private static final String TAG = "NetworkStats";
    
iface value when interface details unavailable. /** {@link #iface} value when interface details unavailable. */
    public static final String IFACE_ALL = null;
    
uid value when UID details unavailable. /** {@link #uid} value when UID details unavailable. */
    public static final int UID_ALL = -1;
    
tag value matching any tag. /** {@link #tag} value matching any tag. */
    // TODO: Rename TAG_ALL to TAG_ANY.
    public static final int TAG_ALL = -1;
    
set value for all sets combined, not including debug sets. /** {@link #set} value for all sets combined, not including debug sets. */
    public static final int SET_ALL = -1;
    
set value where background data is accounted. /** {@link #set} value where background data is accounted. */
    public static final int SET_DEFAULT = 0;
    
set value where foreground data is accounted. /** {@link #set} value where foreground data is accounted. */
    public static final int SET_FOREGROUND = 1;
    
All set value greater than SET_DEBUG_START are debug set values. /** All {@link #set} value greater than SET_DEBUG_START are debug {@link #set} values. */
    public static final int SET_DEBUG_START = 1000;
    
Debug set value when the VPN stats are moved in. /** Debug {@link #set} value when the VPN stats are moved in. */
    public static final int SET_DBG_VPN_IN = 1001;
    
Debug 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. */
    public static final int SET_DBG_VPN_OUT = 1002;

    
Include all interfaces when filtering /** Include all interfaces when filtering */
    public static final String[] INTERFACES_ALL = null;

    
tag value for total data across all tags. /** {@link #tag} value for total data across all tags. */
    // TODO: Rename TAG_NONE to TAG_ALL.
    public static final int TAG_NONE = 0;

    
metered value to account for all metered states. /** {@link #metered} value to account for all metered states. */
    public static final int METERED_ALL = -1;
    
metered value where native, unmetered data is accounted. /** {@link #metered} value where native, unmetered data is accounted. */
    public static final int METERED_NO = 0;
    
metered value where metered data is accounted. /** {@link #metered} value where metered data is accounted. */
    public static final int METERED_YES = 1;

    
roaming value to account for all roaming states. /** {@link #roaming} value to account for all roaming states. */
    public static final int ROAMING_ALL = -1;
    
roaming value where native, non-roaming data is accounted. /** {@link #roaming} value where native, non-roaming data is accounted. */
    public static final int ROAMING_NO = 0;
    
roaming value where roaming data is accounted. /** {@link #roaming} value where roaming data is accounted. */
    public static final int ROAMING_YES = 1;

    
onDefaultNetwork value to account for all default network states. /** {@link #onDefaultNetwork} value to account for all default network states. */
    public static final int DEFAULT_NETWORK_ALL = -1;
    
onDefaultNetwork value to account for usage while not the default network. /** {@link #onDefaultNetwork} value to account for usage while not the default network. */
    public static final int DEFAULT_NETWORK_NO = 0;
    
onDefaultNetwork value to account for usage while the default network. /** {@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. /** Denotes a request for stats at the interface level. */
    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. */
    public static final int STATS_PER_UID = 1;

    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.
    private static final int IPV4V6_HEADER_DELTA = 20;

    // TODO: move fields to "mVariable" notation

    
SystemClock.elapsedRealtime() timestamp when this data was generated. /**
     * {@link SystemClock#elapsedRealtime()} timestamp when this data was
     * generated.
     */
    private long elapsedRealtime;
    private int size;
    private int capacity;
    private String[] iface;
    private int[] uid;
    private int[] set;
    private int[] tag;
    private int[] metered;
    private int[] roaming;
    private int[] defaultNetwork;
    private long[] rxBytes;
    private long[] rxPackets;
    private long[] txBytes;
    private long[] txPackets;
    private long[] operations;

    public static class Entry {
        public String iface;
        public int uid;
        public int set;
        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().
/**
         * 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().
         */
        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().
/**
         * 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().
         */
        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().
/**
         * 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().
         */
        public int defaultNetwork;
        public long rxBytes;
        public long rxPackets;
        public long txBytes;
        public long txPackets;
        public long operations;

        public Entry() {
            this(IFACE_ALL, UID_ALL, SET_DEFAULT, TAG_NONE, 0L, 0L, 0L, 0L, 0L);
        }

        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);
        }

        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) {
            this.iface = iface;
            this.uid = uid;
            this.set = set;
            this.tag = tag;
            this.metered = metered;
            this.roaming = roaming;
            this.defaultNetwork = defaultNetwork;
            this.rxBytes = rxBytes;
            this.rxPackets = rxPackets;
            this.txBytes = txBytes;
            this.txPackets = txPackets;
            this.operations = operations;
        }

        public boolean isNegative() {
            return rxBytes < 0 || rxPackets < 0 || txBytes < 0 || txPackets < 0 || operations < 0;
        }

        public boolean isEmpty() {
            return rxBytes == 0 && rxPackets == 0 && txBytes == 0 && txPackets == 0
                    && operations == 0;
        }

        public void add(Entry another) {
            this.rxBytes += another.rxBytes;
            this.rxPackets += another.rxPackets;
            this.txBytes += another.txBytes;
            this.txPackets += another.txPackets;
            this.operations += another.operations;
        }

        @Override
        public String toString() {
            final StringBuilder builder = new StringBuilder();
            builder.append("iface=").append(iface);
            builder.append(" uid=").append(uid);
            builder.append(" set=").append(setToString(set));
            builder.append(" tag=").append(tagToString(tag));
            builder.append(" metered=").append(meteredToString(metered));
            builder.append(" roaming=").append(roamingToString(roaming));
            builder.append(" defaultNetwork=").append(defaultNetworkToString(defaultNetwork));
            builder.append(" rxBytes=").append(rxBytes);
            builder.append(" rxPackets=").append(rxPackets);
            builder.append(" txBytes=").append(txBytes);
            builder.append(" txPackets=").append(txPackets);
            builder.append(" operations=").append(operations);
            return builder.toString();
        }

        @Override
        public boolean equals(Object o) {
            if (o instanceof Entry) {
                final Entry e = (Entry) o;
                return uid == e.uid && set == e.set && tag == e.tag && metered == e.metered
                        && roaming == e.roaming && defaultNetwork == e.defaultNetwork
                        && rxBytes == e.rxBytes && rxPackets == e.rxPackets
                        && txBytes == e.txBytes && txPackets == e.txPackets
                        && operations == e.operations && iface.equals(e.iface);
            }
            return false;
        }

        @Override
        public int hashCode() {
            return Objects.hash(uid, set, tag, metered, roaming, defaultNetwork, iface);
        }
    }

    public NetworkStats(long elapsedRealtime, int initialSize) {
        this.elapsedRealtime = elapsedRealtime;
        this.size = 0;
        if (initialSize > 0) {
            this.capacity = initialSize;
            this.iface = new String[initialSize];
            this.uid = new int[initialSize];
            this.set = new int[initialSize];
            this.tag = new int[initialSize];
            this.metered = new int[initialSize];
            this.roaming = new int[initialSize];
            this.defaultNetwork = new int[initialSize];
            this.rxBytes = new long[initialSize];
            this.rxPackets = new long[initialSize];
            this.txBytes = new long[initialSize];
            this.txPackets = new long[initialSize];
            this.operations = new long[initialSize];
        } else {
            // Special case for use by NetworkStatsFactory to start out *really* empty.
            clear();
        }
    }

    public NetworkStats(Parcel parcel) {
        elapsedRealtime = parcel.readLong();
        size = parcel.readInt();
        capacity = parcel.readInt();
        iface = parcel.createStringArray();
        uid = parcel.createIntArray();
        set = parcel.createIntArray();
        tag = parcel.createIntArray();
        metered = parcel.createIntArray();
        roaming = parcel.createIntArray();
        defaultNetwork = parcel.createIntArray();
        rxBytes = parcel.createLongArray();
        rxPackets = parcel.createLongArray();
        txBytes = parcel.createLongArray();
        txPackets = parcel.createLongArray();
        operations = parcel.createLongArray();
    }

    @Override
    public void writeToParcel(Parcel dest, int flags) {
        dest.writeLong(elapsedRealtime);
        dest.writeInt(size);
        dest.writeInt(capacity);
        dest.writeStringArray(iface);
        dest.writeIntArray(uid);
        dest.writeIntArray(set);
        dest.writeIntArray(tag);
        dest.writeIntArray(metered);
        dest.writeIntArray(roaming);
        dest.writeIntArray(defaultNetwork);
        dest.writeLongArray(rxBytes);
        dest.writeLongArray(rxPackets);
        dest.writeLongArray(txBytes);
        dest.writeLongArray(txPackets);
        dest.writeLongArray(operations);
    }

    @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);
        }
        return clone;
    }

    
Clear all data stored in this object.
/**
     * Clear all data stored in this object.
     */
    public void clear() {
        this.capacity = 0;
        this.iface = EmptyArray.STRING;
        this.uid = EmptyArray.INT;
        this.set = EmptyArray.INT;
        this.tag = EmptyArray.INT;
        this.metered = EmptyArray.INT;
        this.roaming = EmptyArray.INT;
        this.defaultNetwork = EmptyArray.INT;
        this.rxBytes = EmptyArray.LONG;
        this.rxPackets = EmptyArray.LONG;
        this.txBytes = EmptyArray.LONG;
        this.txPackets = EmptyArray.LONG;
        this.operations = EmptyArray.LONG;
    }

    @VisibleForTesting
    public NetworkStats addIfaceValues(
            String iface, long rxBytes, long rxPackets, long txBytes, long txPackets) {
        return addValues(
                iface, UID_ALL, SET_DEFAULT, TAG_NONE, rxBytes, rxPackets, txBytes, txPackets, 0L);
    }

    @VisibleForTesting
    public NetworkStats addValues(String iface, int uid, int set, int tag, long rxBytes,
            long rxPackets, long txBytes, long txPackets, long operations) {
        return addValues(new Entry(
                iface, uid, set, tag, rxBytes, rxPackets, txBytes, txPackets, operations));
    }

    @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(
                iface, uid, set, tag, metered, roaming, defaultNetwork, rxBytes, rxPackets,
                txBytes, txPackets, operations));
    }

    
Add new stats entry, copying from given Entry. The Entry object can be recycled across multiple calls. /**
     * Add new stats entry, copying from given {@link Entry}. The {@link Entry}
     * object can be recycled across multiple calls.
     */
    public NetworkStats addValues(Entry entry) {
        if (size >= capacity) {
            final int newLength = Math.max(size, 10) * 3 / 2;
            iface = Arrays.copyOf(iface, newLength);
            uid = Arrays.copyOf(uid, newLength);
            set = Arrays.copyOf(set, newLength);
            tag = Arrays.copyOf(tag, newLength);
            metered = Arrays.copyOf(metered, newLength);
            roaming = Arrays.copyOf(roaming, newLength);
            defaultNetwork = Arrays.copyOf(defaultNetwork, newLength);
            rxBytes = Arrays.copyOf(rxBytes, newLength);
            rxPackets = Arrays.copyOf(rxPackets, newLength);
            txBytes = Arrays.copyOf(txBytes, newLength);
            txPackets = Arrays.copyOf(txPackets, newLength);
            operations = Arrays.copyOf(operations, newLength);
            capacity = newLength;
        }

        setValues(size, entry);
        size++;

        return this;
    }

    private void setValues(int i, Entry entry) {
        iface[i] = entry.iface;
        uid[i] = entry.uid;
        set[i] = entry.set;
        tag[i] = entry.tag;
        metered[i] = entry.metered;
        roaming[i] = entry.roaming;
        defaultNetwork[i] = entry.defaultNetwork;
        rxBytes[i] = entry.rxBytes;
        rxPackets[i] = entry.rxPackets;
        txBytes[i] = entry.txBytes;
        txPackets[i] = entry.txPackets;
        operations[i] = entry.operations;
    }

    
Return specific stats entry.
/**
     * Return specific stats entry.
     */
    public Entry getValues(int i, Entry recycle) {
        final Entry entry = recycle != null ? recycle : new Entry();
        entry.iface = iface[i];
        entry.uid = uid[i];
        entry.set = set[i];
        entry.tag = tag[i];
        entry.metered = metered[i];
        entry.roaming = roaming[i];
        entry.defaultNetwork = defaultNetwork[i];
        entry.rxBytes = rxBytes[i];
        entry.rxPackets = rxPackets[i];
        entry.txBytes = txBytes[i];
        entry.txPackets = txPackets[i];
        entry.operations = operations[i];
        return entry;
    }

    public long getElapsedRealtime() {
        return elapsedRealtime;
    }

    public void setElapsedRealtime(long time) {
        elapsedRealtime = time;
    }

    
Return age of this NetworkStats object with respect to SystemClock.elapsedRealtime(). /**
     * Return age of this {@link NetworkStats} object with respect to
     * {@link SystemClock#elapsedRealtime()}.
     */
    public long getElapsedRealtimeAge() {
        return SystemClock.elapsedRealtime() - elapsedRealtime;
    }

    public int size() {
        return size;
    }

    @VisibleForTesting
    public int internalSize() {
        return capacity;
    }

    @Deprecated
    public NetworkStats combineValues(String iface, int uid, int tag, long rxBytes, long rxPackets,
            long txBytes, long txPackets, long operations) {
        return combineValues(
                iface, uid, SET_DEFAULT, tag, rxBytes, rxPackets, txBytes,
                txPackets, operations);
    }

    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(
                iface, uid, set, tag, rxBytes, rxPackets, txBytes, txPackets, operations));
    }

    
Combine given values with an existing row, or create a new row if findIndex(String, int, int, int, int) is unable to find match. Can also be used to subtract values from existing rows. /**
     * 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.
     */
    public NetworkStats combineValues(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);
        } else {
            rxBytes[i] += entry.rxBytes;
            rxPackets[i] += entry.rxPackets;
            txBytes[i] += entry.txBytes;
            txPackets[i] += entry.txPackets;
            operations[i] += entry.operations;
        }
        return this;
    }

    
Combine all values from another NetworkStats into this object. /**
     * Combine all values from another {@link NetworkStats} into this object.
     */
    public void combineAllValues(NetworkStats another) {
        NetworkStats.Entry entry = null;
        for (int i = 0; i < another.size; i++) {
            entry = another.getValues(i, entry);
            combineValues(entry);
        }
    }

    
Find first stats index that matches the requested parameters.
/**
     * Find first stats index that matches the requested parameters.
     */
    public int findIndex(String iface, int uid, int set, int tag, int metered, int roaming,
            int defaultNetwork) {
        for (int i = 0; i < size; i++) {
            if (uid == this.uid[i] && set == this.set[i] && tag == this.tag[i]
                    && metered == this.metered[i] && roaming == this.roaming[i]
                    && defaultNetwork == this.defaultNetwork[i]
                    && Objects.equals(iface, this.iface[i])) {
                return i;
            }
        }
        return -1;
    }

    
Find first stats index that matches the requested parameters, starting
search around the hinted index as an optimization.
/**
     * Find first stats index that matches the requested parameters, starting
     * search around the hinted index as an optimization.
     */
    @VisibleForTesting
    public int findIndexHinted(String iface, int uid, int set, int tag, int metered, int roaming,
            int defaultNetwork, int hintIndex) {
        for (int offset = 0; offset < size; offset++) {
            final int halfOffset = offset / 2;

            // search outwards from hint index, alternating forward and backward
            final int i;
            if (offset % 2 == 0) {
                i = (hintIndex + halfOffset) % size;
            } else {
                i = (size + hintIndex - halfOffset - 1) % size;
            }

            if (uid == this.uid[i] && set == this.set[i] && tag == this.tag[i]
                    && metered == this.metered[i] && roaming == this.roaming[i]
                    && defaultNetwork == this.defaultNetwork[i]
                    && Objects.equals(iface, this.iface[i])) {
                return i;
            }
        }
        return -1;
    }

    
Splice in operations from the given NetworkStats based on matching uid and tag rows. Ignores iface, since operation counts are at data layer. /**
     * 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.
     */
    public void spliceOperationsFrom(NetworkStats stats) {
        for (int i = 0; i < size; i++) {
            final int j = stats.findIndex(iface[i], uid[i], set[i], tag[i], metered[i], roaming[i],
                    defaultNetwork[i]);
            if (j == -1) {
                operations[i] = 0;
            } else {
                operations[i] = stats.operations[j];
            }
        }
    }

    
Return list of unique interfaces known by this data structure.
/**
     * Return list of unique interfaces known by this data structure.
     */
    public String[] getUniqueIfaces() {
        final HashSet<String> ifaces = new HashSet<String>();
        for (String iface : this.iface) {
            if (iface != IFACE_ALL) {
                ifaces.add(iface);
            }
        }
        return ifaces.toArray(new String[ifaces.size()]);
    }

    
Return list of unique UIDs known by this data structure.
/**
     * Return list of unique UIDs known by this data structure.
     */
    public int[] getUniqueUids() {
        final SparseBooleanArray uids = new SparseBooleanArray();
        for (int uid : this.uid) {
            uids.put(uid, true);
        }

        final int size = uids.size();
        final int[] result = new int[size];
        for (int i = 0; i < size; i++) {
            result[i] = uids.keyAt(i);
        }
        return result;
    }

    
Return total bytes represented by this snapshot object, usually used when checking if a subtract(NetworkStats) delta passes a threshold. /**
     * Return total bytes represented by this snapshot object, usually used when
     * checking if a {@link #subtract(NetworkStats)} delta passes a threshold.
     */
    public long getTotalBytes() {
        final Entry entry = getTotal(null);
        return entry.rxBytes + entry.txBytes;
    }

    
Return total of all fields represented by this snapshot object.
/**
     * Return total of all fields represented by this snapshot object.
     */
    public Entry getTotal(Entry recycle) {
        return getTotal(recycle, null, UID_ALL, false);
    }

    
Return total of all fields represented by this snapshot object matching the requested uid. /**
     * Return total of all fields represented by this snapshot object matching
     * the requested {@link #uid}.
     */
    public Entry getTotal(Entry recycle, int limitUid) {
        return getTotal(recycle, null, limitUid, false);
    }

    
Return total of all fields represented by this snapshot object matching the requested iface. /**
     * Return total of all fields represented by this snapshot object matching
     * the requested {@link #iface}.
     */
    public Entry getTotal(Entry recycle, HashSet<String> limitIface) {
        return getTotal(recycle, limitIface, UID_ALL, false);
    }

    public Entry getTotalIncludingTags(Entry recycle) {
        return getTotal(recycle, null, UID_ALL, true);
    }

    
Return total of all fields represented by this snapshot object matching the requested iface and uid. 
Params:
limitIface – Set of iface to include in total; or 
           null to include all ifaces./**
     * Return total of all fields represented by this snapshot object matching
     * the requested {@link #iface} and {@link #uid}.
     *
     * @param limitIface Set of {@link #iface} to include in total; or {@code
     *            null} to include all ifaces.
     */
    private Entry getTotal(
            Entry recycle, HashSet<String> limitIface, int limitUid, boolean includeTags) {
        final Entry entry = recycle != null ? recycle : new Entry();

        entry.iface = IFACE_ALL;
        entry.uid = limitUid;
        entry.set = SET_ALL;
        entry.tag = TAG_NONE;
        entry.metered = METERED_ALL;
        entry.roaming = ROAMING_ALL;
        entry.defaultNetwork = DEFAULT_NETWORK_ALL;
        entry.rxBytes = 0;
        entry.rxPackets = 0;
        entry.txBytes = 0;
        entry.txPackets = 0;
        entry.operations = 0;

        for (int i = 0; i < size; i++) {
            final boolean matchesUid = (limitUid == UID_ALL) || (limitUid == uid[i]);
            final boolean matchesIface = (limitIface == null) || (limitIface.contains(iface[i]));

            if (matchesUid && matchesIface) {
                // skip specific tags, since already counted in TAG_NONE
                if (tag[i] != TAG_NONE && !includeTags) continue;

                entry.rxBytes += rxBytes[i];
                entry.rxPackets += rxPackets[i];
                entry.txBytes += txBytes[i];
                entry.txPackets += txPackets[i];
                entry.operations += operations[i];
            }
        }
        return entry;
    }

    
Fast path for battery stats.
/**
     * Fast path for battery stats.
     */
    public long getTotalPackets() {
        long total = 0;
        for (int i = size-1; i >= 0; i--) {
            total += rxPackets[i] + txPackets[i];
        }
        return total;
    }

    
Subtract the given NetworkStats, effectively leaving the delta between two snapshots in time. Assumes that statistics rows collect over time, and that none of them have disappeared. /**
     * 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.
     */
    public NetworkStats subtract(NetworkStats right) {
        return subtract(this, right, null, null);
    }

    
Subtract the two given NetworkStats objects, returning the delta between two snapshots in time. Assumes that statistics rows collect over time, and that none of them have disappeared. 
 If counters have rolled backwards, they are clamped to 0 and reported to the given NonMonotonicObserver. /**
     * Subtract the two given {@link NetworkStats} objects, returning the delta
     * between two snapshots in time. Assumes that statistics rows collect over
     * time, and that none of them have disappeared.
     * <p>
     * If counters have rolled backwards, they are clamped to {@code 0} and
     * reported to the given {@link NonMonotonicObserver}.
     */
    public static <C> NetworkStats subtract(NetworkStats left, NetworkStats right,
            NonMonotonicObserver<C> observer, C cookie) {
        return subtract(left, right, observer, cookie, null);
    }

    
Subtract the two given NetworkStats objects, returning the delta between two snapshots in time. Assumes that statistics rows collect over time, and that none of them have disappeared. 
 If counters have rolled backwards, they are clamped to 0 and reported to the given NonMonotonicObserver. 

If recycle is supplied, this NetworkStats object will be
reused (and returned) as the result if it is large enough to contain
the data.
/**
     * Subtract the two given {@link NetworkStats} objects, returning the delta
     * between two snapshots in time. Assumes that statistics rows collect over
     * time, and that none of them have disappeared.
     * <p>
     * If counters have rolled backwards, they are clamped to {@code 0} and
     * reported to the given {@link NonMonotonicObserver}.
     * <p>
     * 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.
     */
    public static <C> NetworkStats subtract(NetworkStats left, NetworkStats right,
            NonMonotonicObserver<C> observer, C cookie, NetworkStats recycle) {
        long deltaRealtime = left.elapsedRealtime - right.elapsedRealtime;
        if (deltaRealtime < 0) {
            if (observer != null) {
                observer.foundNonMonotonic(left, -1, right, -1, cookie);
            }
            deltaRealtime = 0;
        }

        // result will have our rows, and elapsed time between snapshots
        final Entry entry = new Entry();
        final NetworkStats result;
        if (recycle != null && recycle.capacity >= left.size) {
            result = recycle;
            result.size = 0;
            result.elapsedRealtime = deltaRealtime;
        } else {
            result = new NetworkStats(deltaRealtime, left.size);
        }
        for (int i = 0; i < left.size; i++) {
            entry.iface = left.iface[i];
            entry.uid = left.uid[i];
            entry.set = left.set[i];
            entry.tag = left.tag[i];
            entry.metered = left.metered[i];
            entry.roaming = left.roaming[i];
            entry.defaultNetwork = left.defaultNetwork[i];
            entry.rxBytes = left.rxBytes[i];
            entry.rxPackets = left.rxPackets[i];
            entry.txBytes = left.txBytes[i];
            entry.txPackets = left.txPackets[i];
            entry.operations = left.operations[i];

            // find remote row that matches, and subtract
            final int j = right.findIndexHinted(entry.iface, entry.uid, entry.set, entry.tag,
                    entry.metered, entry.roaming, entry.defaultNetwork, i);
            if (j != -1) {
                // Found matching row, subtract remote value.
                entry.rxBytes -= right.rxBytes[j];
                entry.rxPackets -= right.rxPackets[j];
                entry.txBytes -= right.txBytes[j];
                entry.txPackets -= right.txPackets[j];
                entry.operations -= right.operations[j];
            }

            if (entry.isNegative()) {
                if (observer != null) {
                    observer.foundNonMonotonic(left, i, right, j, cookie);
                }
                entry.rxBytes = Math.max(entry.rxBytes, 0);
                entry.rxPackets = Math.max(entry.rxPackets, 0);
                entry.txBytes = Math.max(entry.txBytes, 0);
                entry.txPackets = Math.max(entry.txPackets, 0);
                entry.operations = Math.max(entry.operations, 0);
            }

            result.addValues(entry);
        }

        return result;
    }

    
Calculate and apply adjustments to captured statistics for 464xlat traffic counted twice.
This mutates both base and stacked traffic stats, to account respectively for
double-counted traffic and IPv4/IPv6 header size difference.
For 464xlat traffic, xt_qtaguid sees every IPv4 packet twice, once as a native IPv4
packet on the stacked interface, and once as translated to an IPv6 packet on the
base interface. For correct stats accounting on the base interface, every 464xlat
packet needs to be subtracted from the root UID on the base interface both for tx
and rx traffic (http://b/12249687, http:/b/33681750).
As for eBPF, the per uid stats is collected by different hook, the rx packets on base
interface will not be counted. Thus, the adjustment on root uid is only needed in tx
direction.
This method will behave fine if stackedIfaces is an non-synchronized but add-only ConcurrentHashMap 
Params:
baseTraffic – Traffic on the base interfaces. Will be mutated.
stackedTraffic – Stats with traffic stacked on top of our ifaces. Will also be mutated.
stackedIfaces – Mapping ipv6if -> ipv4if interface where traffic is counted on both.
useBpfStats – True if eBPF is in use./**
     * Calculate and apply adjustments to captured statistics for 464xlat traffic counted twice.
     *
     * <p>This mutates both base and stacked traffic stats, to account respectively for
     * double-counted traffic and IPv4/IPv6 header size difference.
     *
     * <p>For 464xlat traffic, xt_qtaguid sees every IPv4 packet twice, once as a native IPv4
     * packet on the stacked interface, and once as translated to an IPv6 packet on the
     * base interface. For correct stats accounting on the base interface, every 464xlat
     * packet needs to be subtracted from the root UID on the base interface both for tx
     * and rx traffic (http://b/12249687, http:/b/33681750).
     *
     * As for eBPF, the per uid stats is collected by different hook, the rx packets on base
     * interface will not be counted. Thus, the adjustment on root uid is only needed in tx
     * direction.
     *
     * <p>This method will behave fine if {@code stackedIfaces} is an non-synchronized but add-only
     * {@code ConcurrentHashMap}
     * @param baseTraffic Traffic on the base interfaces. Will be mutated.
     * @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.
     */
    public static void apply464xlatAdjustments(NetworkStats baseTraffic,
            NetworkStats stackedTraffic, Map<String, String> stackedIfaces, boolean useBpfStats) {
        // Total 464xlat traffic to subtract from uid 0 on all base interfaces.
        // stackedIfaces may grow afterwards, but NetworkStats will just be resized automatically.
        final NetworkStats adjustments = new NetworkStats(0, stackedIfaces.size());

        // For recycling
        Entry entry = null;
        Entry adjust = new NetworkStats.Entry(IFACE_ALL, 0, 0, 0, 0, 0, 0, 0L, 0L, 0L, 0L, 0L);

        for (int i = 0; i < stackedTraffic.size; i++) {
            entry = stackedTraffic.getValues(i, entry);
            if (entry.iface == null || !entry.iface.startsWith(CLATD_INTERFACE_PREFIX)) {
                continue;
            }
            final String baseIface = stackedIfaces.get(entry.iface);
            if (baseIface == null) {
                continue;
            }
            // Subtract any 464lat traffic seen for the root UID on the current base interface.
            // However, for eBPF, the per uid stats is collected by different hook, the rx packets
            // on base interface will not be counted. Thus, the adjustment on root uid is only
            // needed in tx direction.
            adjust.iface = baseIface;
            if (!useBpfStats) {
                adjust.rxBytes = -(entry.rxBytes + entry.rxPackets * IPV4V6_HEADER_DELTA);
                adjust.rxPackets = -entry.rxPackets;
            }
            adjust.txBytes = -(entry.txBytes + entry.txPackets * IPV4V6_HEADER_DELTA);
            adjust.txPackets = -entry.txPackets;
            adjustments.combineValues(adjust);

            // For 464xlat traffic, per uid stats only counts the bytes of the native IPv4 packet
            // sent on the stacked interface with prefix "v4-" and drops the IPv6 header size after
            // unwrapping. To account correctly for on-the-wire traffic, add the 20 additional bytes
            // difference for all packets (http://b/12249687, http:/b/33681750).
            entry.rxBytes += entry.rxPackets * IPV4V6_HEADER_DELTA;
            entry.txBytes += entry.txPackets * IPV4V6_HEADER_DELTA;
            stackedTraffic.setValues(i, entry);
        }

        baseTraffic.combineAllValues(adjustments);
    }

    
Calculate and apply adjustments to captured statistics for 464xlat traffic counted twice.
This mutates the object this method is called on. Equivalent to calling apply464xlatAdjustments(NetworkStats, NetworkStats, Map<String,String>) with this as base and stacked traffic. 
Params:
stackedIfaces – Mapping ipv6if -> ipv4if interface where traffic is counted on both./**
     * Calculate and apply adjustments to captured statistics for 464xlat traffic counted twice.
     *
     * <p>This mutates the object this method is called on. Equivalent to calling
     * {@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.
     */
    public void apply464xlatAdjustments(Map<String, String> stackedIfaces, boolean useBpfStats) {
        apply464xlatAdjustments(this, this, stackedIfaces, useBpfStats);
    }

    
Return total statistics grouped by iface; doesn't mutate the original structure. /**
     * Return total statistics grouped by {@link #iface}; doesn't mutate the
     * original structure.
     */
    public NetworkStats groupedByIface() {
        final NetworkStats stats = new NetworkStats(elapsedRealtime, 10);

        final Entry entry = new Entry();
        entry.uid = UID_ALL;
        entry.set = SET_ALL;
        entry.tag = TAG_NONE;
        entry.metered = METERED_ALL;
        entry.roaming = ROAMING_ALL;
        entry.defaultNetwork = DEFAULT_NETWORK_ALL;
        entry.operations = 0L;

        for (int i = 0; i < size; i++) {
            // skip specific tags, since already counted in TAG_NONE
            if (tag[i] != TAG_NONE) continue;

            entry.iface = iface[i];
            entry.rxBytes = rxBytes[i];
            entry.rxPackets = rxPackets[i];
            entry.txBytes = txBytes[i];
            entry.txPackets = txPackets[i];
            stats.combineValues(entry);
        }

        return stats;
    }

    
Return total statistics grouped by uid; doesn't mutate the original structure. /**
     * Return total statistics grouped by {@link #uid}; doesn't mutate the
     * original structure.
     */
    public NetworkStats groupedByUid() {
        final NetworkStats stats = new NetworkStats(elapsedRealtime, 10);

        final Entry entry = new Entry();
        entry.iface = IFACE_ALL;
        entry.set = SET_ALL;
        entry.tag = TAG_NONE;
        entry.metered = METERED_ALL;
        entry.roaming = ROAMING_ALL;
        entry.defaultNetwork = DEFAULT_NETWORK_ALL;

        for (int i = 0; i < size; i++) {
            // skip specific tags, since already counted in TAG_NONE
            if (tag[i] != TAG_NONE) continue;

            entry.uid = uid[i];
            entry.rxBytes = rxBytes[i];
            entry.rxPackets = rxPackets[i];
            entry.txBytes = txBytes[i];
            entry.txPackets = txPackets[i];
            entry.operations = operations[i];
            stats.combineValues(entry);
        }

        return stats;
    }

    
Return all rows except those attributed to the requested UID; doesn't
mutate the original structure.
/**
     * Return all rows except those attributed to the requested UID; doesn't
     * mutate the original structure.
     */
    public NetworkStats withoutUids(int[] uids) {
        final NetworkStats stats = new NetworkStats(elapsedRealtime, 10);

        Entry entry = new Entry();
        for (int i = 0; i < size; i++) {
            entry = getValues(i, entry);
            if (!ArrayUtils.contains(uids, entry.uid)) {
                stats.addValues(entry);
            }
        }

        return stats;
    }

    
Only keep entries that match all specified filters.
This mutates the original structure in place. After this method is called,
size is the number of matching entries, and capacity is the previous capacity.
Params:
limitUid – UID to filter for, or UID_ALL.
limitIfaces – Interfaces to filter for, or INTERFACES_ALL.
limitTag – Tag to filter for, or TAG_ALL./**
     * Only keep entries that match all specified filters.
     *
     * <p>This mutates the original structure in place. After this method is called,
     * size is the number of matching entries, and capacity is the previous capacity.
     * @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}.
     */
    public void filter(int limitUid, String[] limitIfaces, int limitTag) {
        if (limitUid == UID_ALL && limitTag == TAG_ALL && limitIfaces == INTERFACES_ALL) {
            return;
        }

        Entry entry = new Entry();
        int nextOutputEntry = 0;
        for (int i = 0; i < size; i++) {
            entry = getValues(i, entry);
            final boolean matches =
                    (limitUid == UID_ALL || limitUid == entry.uid)
                    && (limitTag == TAG_ALL || limitTag == entry.tag)
                    && (limitIfaces == INTERFACES_ALL
                            || ArrayUtils.contains(limitIfaces, entry.iface));

            if (matches) {
                setValues(nextOutputEntry, entry);
                nextOutputEntry++;
            }
        }

        size = nextOutputEntry;
    }

    public void dump(String prefix, PrintWriter pw) {
        pw.print(prefix);
        pw.print("NetworkStats: elapsedRealtime="); pw.println(elapsedRealtime);
        for (int i = 0; i < size; i++) {
            pw.print(prefix);
            pw.print("  ["); pw.print(i); pw.print("]");
            pw.print(" iface="); pw.print(iface[i]);
            pw.print(" uid="); pw.print(uid[i]);
            pw.print(" set="); pw.print(setToString(set[i]));
            pw.print(" tag="); pw.print(tagToString(tag[i]));
            pw.print(" metered="); pw.print(meteredToString(metered[i]));
            pw.print(" roaming="); pw.print(roamingToString(roaming[i]));
            pw.print(" defaultNetwork="); pw.print(defaultNetworkToString(defaultNetwork[i]));
            pw.print(" rxBytes="); pw.print(rxBytes[i]);
            pw.print(" rxPackets="); pw.print(rxPackets[i]);
            pw.print(" txBytes="); pw.print(txBytes[i]);
            pw.print(" txPackets="); pw.print(txPackets[i]);
            pw.print(" operations="); pw.println(operations[i]);
        }
    }

    
Return text description of set value. /**
     * Return text description of {@link #set} value.
     */
    public static String setToString(int set) {
        switch (set) {
            case SET_ALL:
                return "ALL";
            case SET_DEFAULT:
                return "DEFAULT";
            case SET_FOREGROUND:
                return "FOREGROUND";
            case SET_DBG_VPN_IN:
                return "DBG_VPN_IN";
            case SET_DBG_VPN_OUT:
                return "DBG_VPN_OUT";
            default:
                return "UNKNOWN";
        }
    }

    
Return text description of set value. /**
     * Return text description of {@link #set} value.
     */
    public static String setToCheckinString(int set) {
        switch (set) {
            case SET_ALL:
                return "all";
            case SET_DEFAULT:
                return "def";
            case SET_FOREGROUND:
                return "fg";
            case SET_DBG_VPN_IN:
                return "vpnin";
            case SET_DBG_VPN_OUT:
                return "vpnout";
            default:
                return "unk";
        }
    }

    
Returns:
true if the querySet matches the dataSet./**
     * @return true if the querySet matches the dataSet.
     */
    public static boolean setMatches(int querySet, int dataSet) {
        if (querySet == dataSet) {
            return true;
        }
        // SET_ALL matches all non-debugging sets.
        return querySet == SET_ALL && dataSet < SET_DEBUG_START;
    }

    
Return text description of tag value. /**
     * Return text description of {@link #tag} value.
     */
    public static String tagToString(int tag) {
        return "0x" + Integer.toHexString(tag);
    }

    
Return text description of metered value. /**
     * Return text description of {@link #metered} value.
     */
    public static String meteredToString(int metered) {
        switch (metered) {
            case METERED_ALL:
                return "ALL";
            case METERED_NO:
                return "NO";
            case METERED_YES:
                return "YES";
            default:
                return "UNKNOWN";
        }
    }

    
Return text description of roaming value. /**
     * Return text description of {@link #roaming} value.
     */
    public static String roamingToString(int roaming) {
        switch (roaming) {
            case ROAMING_ALL:
                return "ALL";
            case ROAMING_NO:
                return "NO";
            case ROAMING_YES:
                return "YES";
            default:
                return "UNKNOWN";
        }
    }

    
Return text description of defaultNetwork value. /**
     * Return text description of {@link #defaultNetwork} value.
     */
    public static String defaultNetworkToString(int defaultNetwork) {
        switch (defaultNetwork) {
            case DEFAULT_NETWORK_ALL:
                return "ALL";
            case DEFAULT_NETWORK_NO:
                return "NO";
            case DEFAULT_NETWORK_YES:
                return "YES";
            default:
                return "UNKNOWN";
        }
    }

    @Override
    public String toString() {
        final CharArrayWriter writer = new CharArrayWriter();
        dump("", new PrintWriter(writer));
        return writer.toString();
    }

    @Override
    public int describeContents() {
        return 0;
    }

    public static final Creator<NetworkStats> CREATOR = new Creator<NetworkStats>() {
        @Override
        public NetworkStats createFromParcel(Parcel in) {
            return new NetworkStats(in);
        }

        @Override
        public NetworkStats[] newArray(int size) {
            return new NetworkStats[size];
        }
    };

    public interface NonMonotonicObserver<C> {
        public void foundNonMonotonic(
                NetworkStats left, int leftIndex, NetworkStats right, int rightIndex, C cookie);
        public void foundNonMonotonic(
                NetworkStats stats, int statsIndex, C cookie);
    }

    
VPN accounting. Move some VPN's underlying traffic to other UIDs that use tun0 iface. This method should only be called on delta NetworkStats. Do not call this method on a snapshot NetworkStats object because the tunUid and/or the underlyingIface may change over time. This method performs adjustments for one active VPN package and one VPN iface at a time. It is possible for the VPN software to use multiple underlying networks. This method only migrates traffic for the primary underlying network. 
Params:
tunUid – uid of the VPN application
tunIface – iface of the vpn tunnel
underlyingIface – the primary underlying network iface used by the VPN application
Returns:
true if it successfully adjusts the accounting for VPN, false otherwise/**
     * VPN accounting. Move some VPN's underlying traffic to other UIDs that use tun0 iface.
     *
     * This method should only be called on delta NetworkStats. Do not call this method on a
     * snapshot {@link NetworkStats} object because the tunUid and/or the underlyingIface may
     * change over time.
     *
     * This method performs adjustments for one active VPN package and one VPN iface at a time.
     *
     * It is possible for the VPN software to use multiple underlying networks. This method
     * only migrates traffic for the primary underlying network.
     *
     * @param tunUid uid of the VPN application
     * @param tunIface iface of the vpn tunnel
     * @param underlyingIface the primary underlying network iface used by the VPN application
     * @return true if it successfully adjusts the accounting for VPN, false otherwise
     */
    public boolean migrateTun(int tunUid, String tunIface, String underlyingIface) {
        Entry tunIfaceTotal = new Entry();
        Entry underlyingIfaceTotal = new Entry();

        tunAdjustmentInit(tunUid, tunIface, underlyingIface, tunIfaceTotal, underlyingIfaceTotal);

        // If tunIface < underlyingIface, it leaves the overhead traffic in the VPN app.
        // If tunIface > underlyingIface, the VPN app doesn't get credit for data compression.
        // Negative stats should be avoided.
        Entry pool = tunGetPool(tunIfaceTotal, underlyingIfaceTotal);
        if (pool.isEmpty()) {
            return true;
        }
        Entry moved =
                addTrafficToApplications(tunUid, tunIface, underlyingIface, tunIfaceTotal, pool);
        deductTrafficFromVpnApp(tunUid, underlyingIface, moved);

        if (!moved.isEmpty()) {
            Slog.wtf(TAG, "Failed to deduct underlying network traffic from VPN package. Moved="
                    + moved);
            return false;
        }
        return true;
    }

    
Initializes the data used by the migrateTun() method.
This is the first pass iteration which does the following work:
(1) Adds up all the traffic through the tunUid's underlyingIface
    (both foreground and background).
(2) Adds up all the traffic through tun0 excluding traffic from the vpn app itself.
/**
     * Initializes the data used by the migrateTun() method.
     *
     * This is the first pass iteration which does the following work:
     * (1) Adds up all the traffic through the tunUid's underlyingIface
     *     (both foreground and background).
     * (2) Adds up all the traffic through tun0 excluding traffic from the vpn app itself.
     */
    private void tunAdjustmentInit(int tunUid, String tunIface, String underlyingIface,
            Entry tunIfaceTotal, Entry underlyingIfaceTotal) {
        Entry recycle = new Entry();
        for (int i = 0; i < size; i++) {
            getValues(i, recycle);
            if (recycle.uid == UID_ALL) {
                throw new IllegalStateException(
                        "Cannot adjust VPN accounting on an iface aggregated NetworkStats.");
            } if (recycle.set == SET_DBG_VPN_IN || recycle.set == SET_DBG_VPN_OUT) {
                throw new IllegalStateException(
                        "Cannot adjust VPN accounting on a NetworkStats containing SET_DBG_VPN_*");
            }

            if (recycle.uid == tunUid && recycle.tag == TAG_NONE
                    && Objects.equals(underlyingIface, recycle.iface)) {
                underlyingIfaceTotal.add(recycle);
            }

            if (recycle.uid != tunUid && recycle.tag == TAG_NONE
                    && Objects.equals(tunIface, recycle.iface)) {
                // Add up all tunIface traffic excluding traffic from the vpn app itself.
                tunIfaceTotal.add(recycle);
            }
        }
    }

    private static Entry tunGetPool(Entry tunIfaceTotal, Entry underlyingIfaceTotal) {
        Entry pool = new Entry();
        pool.rxBytes = Math.min(tunIfaceTotal.rxBytes, underlyingIfaceTotal.rxBytes);
        pool.rxPackets = Math.min(tunIfaceTotal.rxPackets, underlyingIfaceTotal.rxPackets);
        pool.txBytes = Math.min(tunIfaceTotal.txBytes, underlyingIfaceTotal.txBytes);
        pool.txPackets = Math.min(tunIfaceTotal.txPackets, underlyingIfaceTotal.txPackets);
        pool.operations = Math.min(tunIfaceTotal.operations, underlyingIfaceTotal.operations);
        return pool;
    }

    private Entry addTrafficToApplications(int tunUid, String tunIface, String underlyingIface,
            Entry tunIfaceTotal, Entry pool) {
        Entry moved = new Entry();
        Entry tmpEntry = new Entry();
        tmpEntry.iface = underlyingIface;
        for (int i = 0; i < size; i++) {
            // the vpn app is excluded from the redistribution but all moved traffic will be
            // deducted from the vpn app (see deductTrafficFromVpnApp below).
            if (Objects.equals(iface[i], tunIface) && uid[i] != tunUid) {
                if (tunIfaceTotal.rxBytes > 0) {
                    tmpEntry.rxBytes = pool.rxBytes * rxBytes[i] / tunIfaceTotal.rxBytes;
                } else {
                    tmpEntry.rxBytes = 0;
                }
                if (tunIfaceTotal.rxPackets > 0) {
                    tmpEntry.rxPackets = pool.rxPackets * rxPackets[i] / tunIfaceTotal.rxPackets;
                } else {
                    tmpEntry.rxPackets = 0;
                }
                if (tunIfaceTotal.txBytes > 0) {
                    tmpEntry.txBytes = pool.txBytes * txBytes[i] / tunIfaceTotal.txBytes;
                } else {
                    tmpEntry.txBytes = 0;
                }
                if (tunIfaceTotal.txPackets > 0) {
                    tmpEntry.txPackets = pool.txPackets * txPackets[i] / tunIfaceTotal.txPackets;
                } else {
                    tmpEntry.txPackets = 0;
                }
                if (tunIfaceTotal.operations > 0) {
                    tmpEntry.operations =
                            pool.operations * operations[i] / tunIfaceTotal.operations;
                } else {
                    tmpEntry.operations = 0;
                }
                tmpEntry.uid = uid[i];
                tmpEntry.tag = tag[i];
                tmpEntry.set = set[i];
                tmpEntry.metered = metered[i];
                tmpEntry.roaming = roaming[i];
                tmpEntry.defaultNetwork = defaultNetwork[i];
                combineValues(tmpEntry);
                if (tag[i] == TAG_NONE) {
                    moved.add(tmpEntry);
                    // Add debug info
                    tmpEntry.set = SET_DBG_VPN_IN;
                    combineValues(tmpEntry);
                }
            }
        }
        return moved;
    }

    private void deductTrafficFromVpnApp(int tunUid, String underlyingIface, Entry moved) {
        // Add debug info
        moved.uid = tunUid;
        moved.set = SET_DBG_VPN_OUT;
        moved.tag = TAG_NONE;
        moved.iface = underlyingIface;
        moved.metered = METERED_ALL;
        moved.roaming = ROAMING_ALL;
        moved.defaultNetwork = DEFAULT_NETWORK_ALL;
        combineValues(moved);

        // Caveat: if the vpn software uses tag, the total tagged traffic may be greater than
        // the TAG_NONE traffic.
        //
        // Relies on the fact that the underlying traffic only has state ROAMING_NO and METERED_NO,
        // which should be the case as it comes directly from the /proc file. We only blend in the
        // roaming data after applying these adjustments, by checking the NetworkIdentity of the
        // underlying iface.
        int idxVpnBackground = findIndex(underlyingIface, tunUid, SET_DEFAULT, TAG_NONE,
                METERED_NO, ROAMING_NO, DEFAULT_NETWORK_NO);
        if (idxVpnBackground != -1) {
            tunSubtract(idxVpnBackground, this, moved);
        }

        int idxVpnForeground = findIndex(underlyingIface, tunUid, SET_FOREGROUND, TAG_NONE,
                METERED_NO, ROAMING_NO, DEFAULT_NETWORK_NO);
        if (idxVpnForeground != -1) {
            tunSubtract(idxVpnForeground, this, moved);
        }
    }

    private static void tunSubtract(int i, NetworkStats left, Entry right) {
        long rxBytes = Math.min(left.rxBytes[i], right.rxBytes);
        left.rxBytes[i] -= rxBytes;
        right.rxBytes -= rxBytes;

        long rxPackets = Math.min(left.rxPackets[i], right.rxPackets);
        left.rxPackets[i] -= rxPackets;
        right.rxPackets -= rxPackets;

        long txBytes = Math.min(left.txBytes[i], right.txBytes);
        left.txBytes[i] -= txBytes;
        right.txBytes -= txBytes;

        long txPackets = Math.min(left.txPackets[i], right.txPackets);
        left.txPackets[i] -= txPackets;
        right.txPackets -= txPackets;
    }
}