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NetworkStatsFactory: no double looping on stats + stacked interfaces

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This patch uses the associative structure of the stacked/base interface
collection to avoid the two nested for loops over stacked/base
interfaces and all stats entries when correcting 464xlat traffic stats.

Consequently the list of stats entries is iterated only once.

Test: runtest -x frameworks/base/../NetworkStatsFactoryTest.java
Bug: 33681750
Change-Id: I84ae997fb693b909f431764697627b9957131732
This commit is contained in:
Hugo Benichi
2017-04-27 14:52:53 +09:00
parent 6d58a32565
commit 5efd907d85
1 changed files with 31 additions and 32 deletions
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57
core/java/com/android/internal/net/NetworkStatsFactory.java
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@@ -192,46 +192,43 @@ public class NetworkStatsFactory {
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)) {
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)) {
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);
}
}
// 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;
}
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);
// 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;
adjustments.combineValues(adjust);
// 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;
@@ -239,6 +236,8 @@ public class NetworkStatsFactory {
stats.combineValues(entry);
}
stats.combineAllValues(adjustments);
return stats;
}