Ignore ipv6 tx traffic on clat uid.

Currently, 464xlat counts its ipv6 tx traffic into root uid.
When user is making ipv4 upload over ipv6-only network, ipv4
tx traffic may sometimes be counted faster then ipv6 tx
traffic.

Thus, NetworkStatsService may detect non-monotonic values due
to 464xlat adjustment.

So the solution is that: for clatd, make ipv6 tx traffic counts
into clat uid, and then ignore it in the framework side.

Bug: 118602783
Test: 1. manually verify clatd traffic on clat uid.
      2. runtest frameworks-net

Change-Id: Ifb478b79e3e281918c70e16d1f90682c78f33db1

8 files changed, 52 insertions, 26 deletions

diff --git a/core/java/android/net/NetworkStats.java b/core/java/android/net/NetworkStats.java
index a00b9a3caeba..9cf582bef1d4 100644
--- a/core/java/android/net/NetworkStats.java
+++ b/core/java/android/net/NetworkStats.java
@@ -16,6 +16,8 @@
 
 package android.net;
 
+import static android.os.Process.CLAT_UID;
+
 import android.annotation.UnsupportedAppUsage;
 import android.os.Parcel;
 import android.os.Parcelable;
@@ -828,13 +830,15 @@ public class NetworkStats implements Parcelable {
      *
      * <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).
+     * 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.
      *
      * 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.
+     * 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.
      *
      * <p>This method will behave fine if {@code stackedIfaces} is an non-synchronized but add-only
      * {@code ConcurrentHashMap}
@@ -862,17 +866,14 @@ public class NetworkStats implements Parcelable {
             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.
+            // 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;
             }
-            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
@@ -884,6 +885,9 @@ public class NetworkStats implements Parcelable {
             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);
     }
 
diff --git a/core/java/android/os/Process.java b/core/java/android/os/Process.java
index d0cdf6e75224..5ad876e7240a 100644
--- a/core/java/android/os/Process.java
+++ b/core/java/android/os/Process.java
@@ -109,6 +109,12 @@ public class Process {
     public static final int NFC_UID = 1027;
 
     /**
+     * Defines the UID/GID for the clatd process.
+     * @hide
+     * */
+    public static final int CLAT_UID = 1029;
+
+    /**
      * Defines the UID/GID for the Bluetooth service process.
      * @hide
      */
diff --git a/tests/net/java/android/net/NetworkStatsTest.java b/tests/net/java/android/net/NetworkStatsTest.java
index 1e3a49bd8cc8..2c2afd4c6f1c 100644
--- a/tests/net/java/android/net/NetworkStatsTest.java
+++ b/tests/net/java/android/net/NetworkStatsTest.java
@@ -832,25 +832,23 @@ public class NetworkStatsTest {
                 0 /* operations */);
 
         // Traffic measured for the root uid on the base interface if eBPF is in use.
-        // Incorrectly includes appEntry's bytes and packets, plus IPv4-IPv6 translation
-        // overhead (20 bytes per packet), only for TX traffic.
         final NetworkStats.Entry ebpfRootUidEntry = new NetworkStats.Entry(
                 baseIface, rootUid, SET_DEFAULT, TAG_NONE,
                 163577 /* rxBytes */,
                 187 /* rxPackets */,
-                1169942 /* txBytes */,
-                13902 /* txPackets */,
+                17607 /* txBytes */,
+                97 /* txPackets */,
                 0 /* operations */);
 
         // Traffic measured for the root uid on the base interface if xt_qtaguid is in use.
         // Incorrectly includes appEntry's bytes and packets, plus IPv4-IPv6 translation
-        // overhead (20 bytes per packet), in both directions.
+        // overhead (20 bytes per packet), in rx direction.
         final NetworkStats.Entry xtRootUidEntry = new NetworkStats.Entry(
                 baseIface, rootUid, SET_DEFAULT, TAG_NONE,
                 31113087 /* rxBytes */,
                 22588 /* rxPackets */,
-                1169942 /* txBytes */,
-                13902 /* txPackets */,
+                17607 /* txBytes */,
+                97 /* txPackets */,
                 0 /* operations */);
 
         final NetworkStats.Entry otherEntry = new NetworkStats.Entry(
diff --git a/tests/net/java/com/android/internal/net/NetworkStatsFactoryTest.java b/tests/net/java/com/android/internal/net/NetworkStatsFactoryTest.java
index 788924b1d3bf..90bf7b1a83ed 100644
--- a/tests/net/java/com/android/internal/net/NetworkStatsFactoryTest.java
+++ b/tests/net/java/com/android/internal/net/NetworkStatsFactoryTest.java
@@ -159,7 +159,7 @@ public class NetworkStatsFactoryTest {
         assertStatsEntry(stats, "v4-wlan0", 1000, SET_DEFAULT, 0x0, 30812L, 2310L);
         assertStatsEntry(stats, "v4-wlan0", 10102, SET_DEFAULT, 0x0, 10022L, 3330L);
         assertStatsEntry(stats, "v4-wlan0", 10060, SET_DEFAULT, 0x0, 9532772L, 254112L);
-        assertStatsEntry(stats, "wlan0", 0, SET_DEFAULT, 0x0, 15229L, 5766L);
+        assertStatsEntry(stats, "wlan0", 0, SET_DEFAULT, 0x0, 15229L, 0L);
         assertStatsEntry(stats, "wlan0", 1000, SET_DEFAULT, 0x0, 6126L, 2013L);
         assertStatsEntry(stats, "wlan0", 10013, SET_DEFAULT, 0x0, 0L, 144L);
         assertStatsEntry(stats, "wlan0", 10018, SET_DEFAULT, 0x0, 5980263L, 167667L);
@@ -170,6 +170,8 @@ public class NetworkStatsFactoryTest {
         assertStatsEntry(stats, "dummy0", 0, SET_DEFAULT, 0x0, 0L, 168L);
         assertStatsEntry(stats, "lo", 0, SET_DEFAULT, 0x0, 1288L, 1288L);
 
+        assertNoStatsEntry(stats, "wlan0", 1029, SET_DEFAULT, 0x0);
+
         NetworkStatsFactory.clearStackedIfaces();
     }
 
@@ -191,12 +193,12 @@ public class NetworkStatsFactoryTest {
         // Stats snapshot before the download
         stats = parseDetailedStats(R.raw.xt_qtaguid_with_clat_100mb_download_before);
         assertStatsEntry(stats, "v4-wlan0", 10106, SET_FOREGROUND, 0x0, appRxBytesBefore, 5199872L);
-        assertStatsEntry(stats, "wlan0", 0, SET_DEFAULT, 0x0, rootRxBytesBefore, 647888L);
+        assertStatsEntry(stats, "wlan0", 0, SET_DEFAULT, 0x0, rootRxBytesBefore, 0L);
 
         // Stats snapshot after the download
         stats = parseDetailedStats(R.raw.xt_qtaguid_with_clat_100mb_download_after);
         assertStatsEntry(stats, "v4-wlan0", 10106, SET_FOREGROUND, 0x0, appRxBytesAfter, 7867488L);
-        assertStatsEntry(stats, "wlan0", 0, SET_DEFAULT, 0x0, rootRxBytesAfter, 647587L);
+        assertStatsEntry(stats, "wlan0", 0, SET_DEFAULT, 0x0, rootRxBytesAfter, 0L);
 
         NetworkStatsFactory.clearStackedIfaces();
     }
@@ -252,6 +254,15 @@ public class NetworkStatsFactoryTest {
         assertEquals("unexpected txBytes", txBytes, entry.txBytes);
     }
 
+    private static void assertNoStatsEntry(NetworkStats stats, String iface, int uid, int set,
+            int tag) {
+        final int i = stats.findIndex(iface, uid, set, tag, METERED_NO, ROAMING_NO,
+                DEFAULT_NETWORK_NO);
+        if (i >= 0) {
+            fail("unexpected NetworkStats entry at " + i);
+        }
+    }
+
     private static void assertStatsEntry(NetworkStats stats, String iface, int uid, int set,
             int tag, long rxBytes, long rxPackets, long txBytes, long txPackets) {
         final int i = stats.findIndex(iface, uid, set, tag, METERED_NO, ROAMING_NO,
diff --git a/tests/net/res/raw/xt_qtaguid_with_clat b/tests/net/res/raw/xt_qtaguid_with_clat
index 77e5c7ba8e62..6cd7499545be 100644
--- a/tests/net/res/raw/xt_qtaguid_with_clat
+++ b/tests/net/res/raw/xt_qtaguid_with_clat
@@ -7,7 +7,7 @@ idx iface acct_tag_hex uid_tag_int cnt_set rx_bytes rx_packets tx_bytes tx_packe
 7 v4-wlan0 0x0 10060 1 1448660 1041 31192 753 1448660 1041 0 0 0 0 31192 753 0 0 0 0
 8 v4-wlan0 0x0 10102 0 9702 16 2870 23 9702 16 0 0 0 0 2870 23 0 0 0 0
 9 v4-wlan0 0x0 10102 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
-10 wlan0 0x0 0 0 11058671 7892 312046 5113 11043898 7811 13117 61 1656 20 306544 5046 3230 38 2272 29
+10 wlan0 0x0 0 0 11058671 7892 0 0 11043898 7811 13117 61 1656 20 0 0 0 0 0 0
 11 wlan0 0x0 0 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
 12 wlan0 0x0 1000 0 6126 13 2013 16 5934 11 192 2 0 0 1821 14 192 2 0 0
 13 wlan0 0x0 1000 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
@@ -41,3 +41,5 @@ idx iface acct_tag_hex uid_tag_int cnt_set rx_bytes rx_packets tx_bytes tx_packe
 41 dummy0 0x0 0 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
 42 lo 0x0 0 0 1288 16 1288 16 0 0 532 8 756 8 0 0 532 8 756 8
 43 lo 0x0 0 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
+44 wlan0 0x0 1029 0 0 0 312046 5113 0 0 0 0 0 0 306544 5046 3230 38 2272 29
+45 wlan0 0x0 1029 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
\ No newline at end of file
diff --git a/tests/net/res/raw/xt_qtaguid_with_clat_100mb_download_after b/tests/net/res/raw/xt_qtaguid_with_clat_100mb_download_after
index c78f84f3c655..9f86153a33cf 100644
--- a/tests/net/res/raw/xt_qtaguid_with_clat_100mb_download_after
+++ b/tests/net/res/raw/xt_qtaguid_with_clat_100mb_download_after
@@ -9,7 +9,7 @@ idx iface acct_tag_hex uid_tag_int cnt_set rx_bytes rx_packets tx_bytes tx_packe
 9 v4-wlan0 0x0 10057 1 728 7 392 7 0 0 728 7 0 0 0 0 392 7 0 0
 10 v4-wlan0 0x0 10106 0 2232 18 2232 18 0 0 2232 18 0 0 0 0 2232 18 0 0
 11 v4-wlan0 0x0 10106 1 432952718 314238 5442288 121260 432950238 314218 2480 20 0 0 5433900 121029 8388 231 0 0
-12 wlan0 0x0 0 0 440746376 329772 8524052 130894 439660007 315369 232001 1276 854368 13127 7871216 121284 108568 1325 544268 8285
+12 wlan0 0x0 0 0 440746376 329772 0 0 439660007 315369 232001 1276 854368 13127 0 0 0 0 0 0
 13 wlan0 0x0 0 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
 14 wlan0 0x0 1000 0 77113 272 56151 575 77113 272 0 0 0 0 19191 190 36960 385 0 0
 15 wlan0 0x0 1000 1 20227 80 8356 72 18539 74 1688 6 0 0 7562 66 794 6 0 0
@@ -185,3 +185,5 @@ idx iface acct_tag_hex uid_tag_int cnt_set rx_bytes rx_packets tx_bytes tx_packe
 185 wlan0 0xffffff0900000000 1000 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
 186 dummy0 0x0 0 0 0 0 168 3 0 0 0 0 0 0 0 0 0 0 168 3
 187 dummy0 0x0 0 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
+188 wlan0 0x0 1029 0 0 0 8524052 130894 0 0 0 0 0 0 7871216 121284 108568 1325 544268 8285
+189 wlan0 0x0 1029 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
diff --git a/tests/net/res/raw/xt_qtaguid_with_clat_100mb_download_before b/tests/net/res/raw/xt_qtaguid_with_clat_100mb_download_before
index d0353876c8d3..ce4bcc3a3b43 100644
--- a/tests/net/res/raw/xt_qtaguid_with_clat_100mb_download_before
+++ b/tests/net/res/raw/xt_qtaguid_with_clat_100mb_download_before
@@ -9,7 +9,7 @@ idx iface acct_tag_hex uid_tag_int cnt_set rx_bytes rx_packets tx_bytes tx_packe
 9 v4-wlan0 0x0 10057 1 728 7 392 7 0 0 728 7 0 0 0 0 392 7 0 0
 10 v4-wlan0 0x0 10106 0 1488 12 1488 12 0 0 1488 12 0 0 0 0 1488 12 0 0
 11 v4-wlan0 0x0 10106 1 323981189 235142 3509032 84542 323979453 235128 1736 14 0 0 3502676 84363 6356 179 0 0
-12 wlan0 0x0 0 0 330187296 250652 5855801 94173 329106990 236273 226202 1255 854104 13124 5208040 84634 103637 1256 544124 8283
+12 wlan0 0x0 0 0 330187296 250652 0 0 329106990 236273 226202 1255 854104 13124 0 0 0 0 0 0
 13 wlan0 0x0 0 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
 14 wlan0 0x0 1000 0 77113 272 56151 575 77113 272 0 0 0 0 19191 190 36960 385 0 0
 15 wlan0 0x0 1000 1 20227 80 8356 72 18539 74 1688 6 0 0 7562 66 794 6 0 0
@@ -183,3 +183,5 @@ idx iface acct_tag_hex uid_tag_int cnt_set rx_bytes rx_packets tx_bytes tx_packe
 183 wlan0 0xffffff0900000000 1000 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
 184 dummy0 0x0 0 0 0 0 168 3 0 0 0 0 0 0 0 0 0 0 168 3
 185 dummy0 0x0 0 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
+186 wlan0 0x0 1029 0 0 0 5855801 94173 0 0 0 0 0 0 5208040 84634 103637 1256 544124 8283
+187 wlan0 0x0 1029 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
diff --git a/tests/net/res/raw/xt_qtaguid_with_clat_simple b/tests/net/res/raw/xt_qtaguid_with_clat_simple
index 7f0e56f3ef6b..8c132e7e0a0e 100644
--- a/tests/net/res/raw/xt_qtaguid_with_clat_simple
+++ b/tests/net/res/raw/xt_qtaguid_with_clat_simple
@@ -1,5 +1,6 @@
 idx iface acct_tag_hex uid_tag_int cnt_set rx_bytes rx_packets tx_bytes tx_packets rx_tcp_bytes rx_tcp_packets rx_udp_bytes rx_udp_packets rx_other_bytes rx_other_packets tx_tcp_bytes tx_tcp_packets tx_udp_bytes tx_udp_packets tx_other_bytes tx_other_packets
-2 v4-wlan0 0x0 10060 0 42600 213 4100 41 42600 213 4100 41 0 0 0 0 0 0 0 0
+2 v4-wlan0 0x0 10060 0 42600 213 4100 41 42600 213 0 0 0 0 4100 41 0 0 0 0
 3 v4-wlan0 0x0 10060 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
-4 wlan0 0x0 0 0 46860 213 4920 41 46860 213 4920 41 0 0 0 0 0 0 0 0
+4 wlan0 0x0 0 0 46860 213 0 0 46860 213 0 0 0 0 0 0 0 0 0 0
 5 wlan0 0x0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
+6 wlan0 0x0 1029 0 0 0 4920 41 0 0 0 0 0 0 4920 41 0 0 0 0