diff --git a/core/java/android/net/NetworkStats.java b/core/java/android/net/NetworkStats.java index b7fb280efd..34e48eb44f 100644 --- a/core/java/android/net/NetworkStats.java +++ b/core/java/android/net/NetworkStats.java @@ -16,8 +16,6 @@ package android.net; -import static android.os.Process.CLAT_UID; - import android.annotation.IntDef; import android.annotation.NonNull; import android.annotation.Nullable; @@ -1047,73 +1045,54 @@ public final class NetworkStats implements Parcelable { } /** - * Calculate and apply adjustments to captured statistics for 464xlat traffic counted twice. + * Calculate and apply adjustments to captured statistics for 464xlat traffic. * - *

This mutates both base and stacked traffic stats, to account respectively for - * double-counted traffic and IPv4/IPv6 header size difference. + *

This mutates stacked traffic stats, to account for 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, if using xt_qtaguid, - * every rx 464xlat packet needs to be subtracted from the root UID on the base interface - * (http://b/12249687, http:/b/33681750), and every tx 464xlat packet which was counted onto - * clat uid should be ignored. + *

UID stats, which are only accounted on the stacked interface, need to be increased + * by 20 bytes/packet to account for translation overhead. * - * 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 not needed. However, the - * tx traffic counted in the same way xt_qtaguid does, so the traffic on clat uid still - * needs to be ignored. + *

The potential additional overhead of 8 bytes/packet for ip fragments is ignored. + * + *

Interface stats need to sum traffic on both stacked and base interface because: + * - eBPF offloaded packets appear only on the stacked interface + * - Non-offloaded ingress packets appear only on the stacked interface + * (due to iptables raw PREROUTING drop rules) + * - Non-offloaded egress packets appear only on the stacked interface + * (due to ignoring traffic from clat daemon by uid match) + * (and of course the 20 bytes/packet overhead needs to be applied to stacked interface stats) * *

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. * @hide */ public static void apply464xlatAdjustments(NetworkStats baseTraffic, - NetworkStats stackedTraffic, Map 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()); - + NetworkStats stackedTraffic, Map stackedIfaces) { // 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 xt_qtaguid 464lat rx traffic seen for the root UID on the current base - // interface. As for eBPF, the per uid stats is collected by different hook, the rx - // packets on base interface will not be counted. - adjust.iface = baseIface; - if (!useBpfStats) { - adjust.rxBytes = -(entry.rxBytes + entry.rxPackets * IPV4V6_HEADER_DELTA); - adjust.rxPackets = -entry.rxPackets; - } - adjustments.combineValues(adjust); + if (entry == null) continue; + if (entry.iface == null) continue; + if (!entry.iface.startsWith(CLATD_INTERFACE_PREFIX)) continue; // 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). + // + // Note: this doesn't account for LRO/GRO/GSO/TSO (ie. >mtu) traffic correctly, nor + // does it correctly account for the 8 extra bytes in the IPv6 fragmentation header. + // + // While the ebpf code path does try to simulate proper post segmentation packet + // counts, we have nothing of the sort of xt_qtaguid stats. entry.rxBytes += entry.rxPackets * IPV4V6_HEADER_DELTA; entry.txBytes += entry.txPackets * IPV4V6_HEADER_DELTA; stackedTraffic.setValues(i, entry); } - - // Traffic on clat uid is v6 tx traffic that is already counted with app uid on the stacked - // v4 interface, so it needs to be removed to avoid double-counting. - baseTraffic.removeUids(new int[] {CLAT_UID}); - baseTraffic.combineAllValues(adjustments); } /** @@ -1125,8 +1104,8 @@ public final class NetworkStats implements Parcelable { * @param stackedIfaces Mapping ipv6if -> ipv4if interface where traffic is counted on both. * @hide */ - public void apply464xlatAdjustments(Map stackedIfaces, boolean useBpfStats) { - apply464xlatAdjustments(this, this, stackedIfaces, useBpfStats); + public void apply464xlatAdjustments(Map stackedIfaces) { + apply464xlatAdjustments(this, this, stackedIfaces); } /** diff --git a/services/core/java/com/android/server/net/NetworkStatsFactory.java b/services/core/java/com/android/server/net/NetworkStatsFactory.java index 3dac106418..86ad0b3086 100644 --- a/services/core/java/com/android/server/net/NetworkStatsFactory.java +++ b/services/core/java/com/android/server/net/NetworkStatsFactory.java @@ -152,12 +152,10 @@ public class NetworkStatsFactory { /** * Applies 464xlat adjustments with ifaces noted with {@link #noteStackedIface(String, String)}. - * @see NetworkStats#apply464xlatAdjustments(NetworkStats, NetworkStats, Map, boolean) + * @see NetworkStats#apply464xlatAdjustments(NetworkStats, NetworkStats, Map) */ - public void apply464xlatAdjustments(NetworkStats baseTraffic, - NetworkStats stackedTraffic, boolean useBpfStats) { - NetworkStats.apply464xlatAdjustments(baseTraffic, stackedTraffic, mStackedIfaces, - useBpfStats); + public void apply464xlatAdjustments(NetworkStats baseTraffic, NetworkStats stackedTraffic) { + NetworkStats.apply464xlatAdjustments(baseTraffic, stackedTraffic, mStackedIfaces); } public NetworkStatsFactory() { @@ -380,7 +378,7 @@ public class NetworkStatsFactory { // network, the overhead is their fault. // No locking here: apply464xlatAdjustments behaves fine with an add-only // ConcurrentHashMap. - delta.apply464xlatAdjustments(mStackedIfaces, mUseBpfStats); + delta.apply464xlatAdjustments(mStackedIfaces); // Migrate data usage over a VPN to the TUN network. for (VpnInfo info : vpnArray) { diff --git a/services/core/java/com/android/server/net/NetworkStatsService.java b/services/core/java/com/android/server/net/NetworkStatsService.java index dcbdfdf7a2..ba9f486092 100644 --- a/services/core/java/com/android/server/net/NetworkStatsService.java +++ b/services/core/java/com/android/server/net/NetworkStatsService.java @@ -1311,21 +1311,39 @@ public class NetworkStatsService extends INetworkStatsService.Stub { } // Traffic occurring on stacked interfaces is usually clatd. - // UID stats are always counted on the stacked interface and never - // on the base interface, because the packets on the base interface - // do not actually match application sockets until they are translated. // - // Interface stats are more complicated. Packets subject to BPF offload - // never appear on the base interface and only appear on the stacked - // interface, so to ensure those packets increment interface stats, interface - // stats from stacked interfaces must be collected. + // UID stats are always counted on the stacked interface and never on the base + // interface, because the packets on the base interface do not actually match + // application sockets (they're not IPv4) and thus the app uid is not known. + // For receive this is obvious: packets must be translated from IPv6 to IPv4 + // before the application socket can be found. + // For transmit: either they go through the clat daemon which by virtue of going + // through userspace strips the original socket association during the IPv4 to + // IPv6 translation process, or they are offloaded by eBPF, which doesn't: + // However, on an ebpf device the accounting is done in cgroup ebpf hooks, + // which don't trigger again post ebpf translation. + // (as such stats accounted to the clat uid are ignored) + // + // Interface stats are more complicated. + // + // eBPF offloaded 464xlat'ed packets never hit base interface ip6tables, and thus + // *all* statistics are collected by iptables on the stacked v4-* interface. + // + // Additionally for ingress all packets bound for the clat IPv6 address are dropped + // in ip6tables raw prerouting and thus even non-offloaded packets are only + // accounted for on the stacked interface. + // + // For egress, packets subject to eBPF offload never appear on the base interface + // and only appear on the stacked interface. Thus to ensure packets increment + // interface stats, we must collate data from stacked interfaces. For xt_qtaguid + // (or non eBPF offloaded) TX they would appear on both, however egress interface + // accounting is explicitly bypassed for traffic from the clat uid. + // final List stackedLinks = state.linkProperties.getStackedLinks(); for (LinkProperties stackedLink : stackedLinks) { final String stackedIface = stackedLink.getInterfaceName(); if (stackedIface != null) { - if (mUseBpfTrafficStats) { - findOrCreateNetworkIdentitySet(mActiveIfaces, stackedIface).add(ident); - } + findOrCreateNetworkIdentitySet(mActiveIfaces, stackedIface).add(ident); findOrCreateNetworkIdentitySet(mActiveUidIfaces, stackedIface).add(ident); if (isMobile) { mobileIfaces.add(stackedIface); @@ -1864,14 +1882,13 @@ public class NetworkStatsService extends INetworkStatsService.Stub { // fold tethering stats and operations into uid snapshot final NetworkStats tetherSnapshot = getNetworkStatsTethering(STATS_PER_UID); tetherSnapshot.filter(UID_ALL, ifaces, TAG_ALL); - mStatsFactory.apply464xlatAdjustments(uidSnapshot, tetherSnapshot, - mUseBpfTrafficStats); + mStatsFactory.apply464xlatAdjustments(uidSnapshot, tetherSnapshot); uidSnapshot.combineAllValues(tetherSnapshot); // get a stale copy of uid stats snapshot provided by providers. final NetworkStats providerStats = getNetworkStatsFromProviders(STATS_PER_UID); providerStats.filter(UID_ALL, ifaces, TAG_ALL); - mStatsFactory.apply464xlatAdjustments(uidSnapshot, providerStats, mUseBpfTrafficStats); + mStatsFactory.apply464xlatAdjustments(uidSnapshot, providerStats); uidSnapshot.combineAllValues(providerStats); uidSnapshot.combineAllValues(mUidOperations);