Merge "NetworkStatsFactory: no double looping on stats + stacked interfaces" am: 16832244

            NetworkStats lastStats) throws IOException {

        final NetworkStats stats =

              readNetworkStatsDetailInternal(limitUid, limitIfaces, limitTag, lastStats);

        NetworkStats.Entry entry = null; // for recycling

        final ArrayMap<String, String> stackedIfaces;

        synchronized (sStackedIfaces) {

            stackedIfaces = new ArrayMap<>(sStackedIfaces);

        }

        // Total 464xlat traffic to subtract from uid 0 on all base interfaces.

        final NetworkStats adjustments = new NetworkStats(0, stackedIfaces.size());

        NetworkStats.Entry entry = null; // For recycling

        // 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).

            final int size = sStackedIfaces.size();

            for (int i = 0; i < size; i++) {

                final String stackedIface = sStackedIfaces.keyAt(i);

                final String baseIface = sStackedIfaces.valueAt(i);

                if (!stackedIface.startsWith(CLATD_INTERFACE_PREFIX)) {

        for (int i = 0; i < stats.size(); i++) {

            entry = stats.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;

            }

            NetworkStats.Entry adjust =

                    new NetworkStats.Entry(baseIface, 0, 0, 0, 0L, 0L, 0L, 0L, 0L);

                for (int j = 0; j < stats.size(); j++) {

                    entry = stats.getValues(j, entry);

                    if (Objects.equals(entry.iface, stackedIface)) {

            // Subtract any 464lat traffic seen for the root UID on the current base interface.

            adjust.rxBytes -= (entry.rxBytes + entry.rxPackets * IPV4V6_HEADER_DELTA);

            adjust.txBytes -= (entry.txBytes + entry.txPackets * IPV4V6_HEADER_DELTA);

            adjust.rxPackets -= entry.rxPackets;

            adjust.txPackets -= entry.txPackets;

                    }

                }

                stats.combineValues(adjust);

            }

        }

            adjustments.combineValues(adjust);

        // For 464xlat traffic, xt_qtaguid only counts the bytes of the inner 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).

        for (int i = 0; i < stats.size(); i++) {

            entry = stats.getValues(i, entry);

            if (entry.iface == null || !entry.iface.startsWith(CLATD_INTERFACE_PREFIX)) {

                continue;

            }

            // For 464xlat traffic, xt_qtaguid 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;

            entry.rxPackets = 0;

            stats.combineValues(entry);

        }

        stats.combineAllValues(adjustments);

        return stats;

    }