From 6c277682d55136fbfdfb4f8de5ac175208071767 Mon Sep 17 00:00:00 2001
From: Junyu Lai <junyulai@google.com>
Date: Wed, 21 Feb 2024 11:10:58 +0800
Subject: [PATCH] Clear TrafficStats cache before getting readings from
 TrafficStats

Currently, TrafficStats have rate-limit on all get* APIs.
It is possible that result of uid traffic is updated but result
of iface is not. Thus, clear cache before read.

Test: atest CtsNetTestCases:android.net.cts.IpSecManagerTest#testIkeOverUdpEncapSocket --rerun-until-failure 100
Test: atest FrameworksNetIntegrationTests:com.android.server.net.integrationtests.NetworkStatsIntegrationTest
Bug: N/A
Change-Id: I1b7574d3062837fdded79cb945b582f2afad859b
---
 .../net/src/android/net/cts/IpSecManagerTest.java    | 12 ++++++++++++
 .../integrationtests/NetworkStatsIntegrationTest.kt  |  9 +++++++++
 2 files changed, 21 insertions(+)

diff --git a/tests/cts/net/src/android/net/cts/IpSecManagerTest.java b/tests/cts/net/src/android/net/cts/IpSecManagerTest.java
index a40ed0f127..b703f773af 100644
--- a/tests/cts/net/src/android/net/cts/IpSecManagerTest.java
+++ b/tests/cts/net/src/android/net/cts/IpSecManagerTest.java
@@ -81,6 +81,7 @@ import androidx.test.InstrumentationRegistry;
 import androidx.test.runner.AndroidJUnit4;
 
 import com.android.modules.utils.build.SdkLevel;
+import com.android.testutils.ConnectivityModuleTest;
 import com.android.testutils.DevSdkIgnoreRule;
 import com.android.testutils.DevSdkIgnoreRule.IgnoreUpTo;
 import com.android.testutils.SkipMainlinePresubmit;
@@ -101,6 +102,7 @@ import java.util.Map;
 import java.util.Map.Entry;
 import java.util.Set;
 
+@ConnectivityModuleTest
 @RunWith(AndroidJUnit4.class)
 @AppModeFull(reason = "Socket cannot bind in instant app mode")
 public class IpSecManagerTest extends IpSecBaseTest {
@@ -444,6 +446,11 @@ public class IpSecManagerTest extends IpSecBaseTest {
             long uidTxDelta = 0;
             long uidRxDelta = 0;
             for (int i = 0; i < 100; i++) {
+                // Clear TrafficStats cache is needed to avoid rate-limit caching for
+                // TrafficStats API results on V+ devices.
+                if (SdkLevel.isAtLeastV()) {
+                    runAsShell(NETWORK_SETTINGS, () -> TrafficStats.clearRateLimitCaches());
+                }
                 uidTxDelta = TrafficStats.getUidTxPackets(Os.getuid()) - uidTxPackets;
                 uidRxDelta = TrafficStats.getUidRxPackets(Os.getuid()) - uidRxPackets;
 
@@ -518,6 +525,11 @@ public class IpSecManagerTest extends IpSecBaseTest {
         }
 
         private static void initStatsChecker() throws Exception {
+            // Clear TrafficStats cache is needed to avoid rate-limit caching for
+            // TrafficStats API results on V+ devices.
+            if (SdkLevel.isAtLeastV()) {
+                runAsShell(NETWORK_SETTINGS, () -> TrafficStats.clearRateLimitCaches());
+            }
             uidTxBytes = TrafficStats.getUidTxBytes(Os.getuid());
             uidRxBytes = TrafficStats.getUidRxBytes(Os.getuid());
             uidTxPackets = TrafficStats.getUidTxPackets(Os.getuid());
diff --git a/tests/integration/src/com/android/server/net/integrationtests/NetworkStatsIntegrationTest.kt b/tests/integration/src/com/android/server/net/integrationtests/NetworkStatsIntegrationTest.kt
index 52e502dd4f..4780c5d4b9 100644
--- a/tests/integration/src/com/android/server/net/integrationtests/NetworkStatsIntegrationTest.kt
+++ b/tests/integration/src/com/android/server/net/integrationtests/NetworkStatsIntegrationTest.kt
@@ -38,6 +38,7 @@ import android.net.TrafficStats
 import android.os.Build
 import android.os.Process
 import androidx.test.platform.app.InstrumentationRegistry
+import com.android.modules.utils.build.SdkLevel
 import com.android.server.net.integrationtests.NetworkStatsIntegrationTest.Direction.DOWNLOAD
 import com.android.server.net.integrationtests.NetworkStatsIntegrationTest.Direction.UPLOAD
 import com.android.testutils.DevSdkIgnoreRule.IgnoreUpTo
@@ -214,6 +215,11 @@ class NetworkStatsIntegrationTest {
         // In practice, for one way 10k download payload, the download usage is about
         // 11222~12880 bytes, with 14~17 packets. And the upload usage is about 1279~1626 bytes
         // with 14~17 packets, which is majorly contributed by TCP ACK packets.
+        // Clear TrafficStats cache is needed to avoid rate-limit caching for
+        // TrafficStats API results on V+ devices.
+        if (SdkLevel.isAtLeastV()) {
+            TrafficStats.clearRateLimitCaches()
+        }
         val snapshotAfterDownload = StatsSnapshot(context, internalInterfaceName)
         val (expectedDownloadLower, expectedDownloadUpper) = getExpectedStatsBounds(
             TEST_DOWNLOAD_SIZE,
@@ -236,6 +242,9 @@ class NetworkStatsIntegrationTest {
         )
 
         // Verify upload data usage accounting.
+        if (SdkLevel.isAtLeastV()) {
+            TrafficStats.clearRateLimitCaches()
+        }
         val snapshotAfterUpload = StatsSnapshot(context, internalInterfaceName)
         val (expectedUploadLower, expectedUploadUpper) = getExpectedStatsBounds(
             TEST_UPLOAD_SIZE,