Remove qtaguid support in NetworkStatsFactory

All devices shipped with S+ release would have 4.9+ kernel
with bpf enabled. And for older devices qtag uid is
already broken for a long time. Hence, it is safe to
remove the related code.

Bug: 234315786
Test: atest FrameworksNetTests CtsNetTestCases \
      ConnectivityCoverageTests
Change-Id: Id2a6bfdf32793e5f48eb74da3b662906e5ed380e
diff --git a/service-t/src/com/android/server/net/NetworkStatsFactory.java b/service-t/src/com/android/server/net/NetworkStatsFactory.java
index 8aa3dbc..4a6741c 100644
--- a/service-t/src/com/android/server/net/NetworkStatsFactory.java
+++ b/service-t/src/com/android/server/net/NetworkStatsFactory.java
@@ -17,9 +17,7 @@
 package com.android.server.net;
 
 import static android.net.NetworkStats.INTERFACES_ALL;
-import static android.net.NetworkStats.SET_ALL;
 import static android.net.NetworkStats.TAG_ALL;
-import static android.net.NetworkStats.TAG_NONE;
 import static android.net.NetworkStats.UID_ALL;
 
 import android.annotation.NonNull;
@@ -28,19 +26,12 @@
 import android.net.NetworkStats;
 import android.net.UnderlyingNetworkInfo;
 import android.os.ServiceSpecificException;
-import android.os.StrictMode;
 import android.os.SystemClock;
 
 import com.android.internal.annotations.GuardedBy;
 import com.android.internal.annotations.VisibleForTesting;
-import com.android.internal.util.ProcFileReader;
-import com.android.net.module.util.CollectionUtils;
 import com.android.server.BpfNetMaps;
 
-import libcore.io.IoUtils;
-
-import java.io.File;
-import java.io.FileInputStream;
 import java.io.IOException;
 import java.net.ProtocolException;
 import java.util.Arrays;
@@ -61,18 +52,6 @@
 
     private static final String TAG = "NetworkStatsFactory";
 
-    private static final boolean USE_NATIVE_PARSING = true;
-    private static final boolean VALIDATE_NATIVE_STATS = false;
-
-    /** Path to {@code /proc/net/xt_qtaguid/iface_stat_all}. */
-    private final File mStatsXtIfaceAll;
-    /** Path to {@code /proc/net/xt_qtaguid/iface_stat_fmt}. */
-    private final File mStatsXtIfaceFmt;
-    /** Path to {@code /proc/net/xt_qtaguid/stats}. */
-    private final File mStatsXtUid;
-
-    private final boolean mUseBpfStats;
-
     private final Context mContext;
 
     private final BpfNetMaps mBpfNetMaps;
@@ -107,12 +86,13 @@
          * are expected to monotonically increase since device boot.
          */
         @NonNull
-        public NetworkStats getNetworkStatsDetail(@Nullable String path, int limitUid,
-                @Nullable String[] limitIfaces, int limitTag, boolean useBpfStats)
-                throws IOException {
+        public NetworkStats getNetworkStatsDetail(int limitUid, @Nullable String[] limitIfaces,
+                int limitTag) throws IOException {
             final NetworkStats stats = new NetworkStats(SystemClock.elapsedRealtime(), 0);
-            final int ret = nativeReadNetworkStatsDetail(stats, path,
-                    limitUid, limitIfaces, limitTag, useBpfStats);
+            // TODO: remove both path and useBpfStats arguments.
+            // The path is never used if useBpfStats is true.
+            final int ret = nativeReadNetworkStatsDetail(stats, null /* path */,
+                    limitUid, limitIfaces, limitTag, true /* useBpfStats */);
             if (ret != 0) {
                 throw new IOException("Failed to parse network stats");
             }
@@ -206,16 +186,11 @@
     }
 
     public NetworkStatsFactory(@NonNull Context ctx) {
-        this(ctx, new File("/proc/"), true, new Dependencies());
+        this(ctx, new Dependencies());
     }
 
     @VisibleForTesting
-    public NetworkStatsFactory(@NonNull Context ctx, File procRoot, boolean useBpfStats,
-            Dependencies deps) {
-        mStatsXtIfaceAll = new File(procRoot, "net/xt_qtaguid/iface_stat_all");
-        mStatsXtIfaceFmt = new File(procRoot, "net/xt_qtaguid/iface_stat_fmt");
-        mStatsXtUid = new File(procRoot, "net/xt_qtaguid/stats");
-        mUseBpfStats = useBpfStats;
+    public NetworkStatsFactory(@NonNull Context ctx, Dependencies deps) {
         mBpfNetMaps = deps.createBpfNetMaps(ctx);
         synchronized (mPersistentDataLock) {
             mPersistSnapshot = new NetworkStats(SystemClock.elapsedRealtime(), -1);
@@ -230,104 +205,18 @@
      * using {@code /proc/net/dev} style hooks, which may include non IP layer
      * traffic. Values monotonically increase since device boot, and may include
      * details about inactive interfaces.
-     *
-     * @throws IllegalStateException when problem parsing stats.
      */
     public NetworkStats readNetworkStatsSummaryDev() throws IOException {
-
-        // Return xt_bpf stats if switched to bpf module.
-        if (mUseBpfStats) return mDeps.getNetworkStatsDev();
-
-        final StrictMode.ThreadPolicy savedPolicy = StrictMode.allowThreadDiskReads();
-
-        final NetworkStats stats = new NetworkStats(SystemClock.elapsedRealtime(), 6);
-        final NetworkStats.Entry entry = new NetworkStats.Entry();
-
-        ProcFileReader reader = null;
-        try {
-            reader = new ProcFileReader(new FileInputStream(mStatsXtIfaceAll));
-
-            while (reader.hasMoreData()) {
-                entry.iface = reader.nextString();
-                entry.uid = UID_ALL;
-                entry.set = SET_ALL;
-                entry.tag = TAG_NONE;
-
-                final boolean active = reader.nextInt() != 0;
-
-                // always include snapshot values
-                entry.rxBytes = reader.nextLong();
-                entry.rxPackets = reader.nextLong();
-                entry.txBytes = reader.nextLong();
-                entry.txPackets = reader.nextLong();
-
-                // fold in active numbers, but only when active
-                if (active) {
-                    entry.rxBytes += reader.nextLong();
-                    entry.rxPackets += reader.nextLong();
-                    entry.txBytes += reader.nextLong();
-                    entry.txPackets += reader.nextLong();
-                }
-
-                stats.insertEntry(entry);
-                reader.finishLine();
-            }
-        } catch (NullPointerException|NumberFormatException e) {
-            throw protocolExceptionWithCause("problem parsing stats", e);
-        } finally {
-            IoUtils.closeQuietly(reader);
-            StrictMode.setThreadPolicy(savedPolicy);
-        }
-        return stats;
+        return mDeps.getNetworkStatsDev();
     }
 
     /**
      * Parse and return interface-level summary {@link NetworkStats}. Designed
      * to return only IP layer traffic. Values monotonically increase since
      * device boot, and may include details about inactive interfaces.
-     *
-     * @throws IllegalStateException when problem parsing stats.
      */
     public NetworkStats readNetworkStatsSummaryXt() throws IOException {
-
-        // Return xt_bpf stats if qtaguid  module is replaced.
-        if (mUseBpfStats) return mDeps.getNetworkStatsDev();
-
-        final StrictMode.ThreadPolicy savedPolicy = StrictMode.allowThreadDiskReads();
-
-        // return null when kernel doesn't support
-        if (!mStatsXtIfaceFmt.exists()) return null;
-
-        final NetworkStats stats = new NetworkStats(SystemClock.elapsedRealtime(), 6);
-        final NetworkStats.Entry entry = new NetworkStats.Entry();
-
-        ProcFileReader reader = null;
-        try {
-            // open and consume header line
-            reader = new ProcFileReader(new FileInputStream(mStatsXtIfaceFmt));
-            reader.finishLine();
-
-            while (reader.hasMoreData()) {
-                entry.iface = reader.nextString();
-                entry.uid = UID_ALL;
-                entry.set = SET_ALL;
-                entry.tag = TAG_NONE;
-
-                entry.rxBytes = reader.nextLong();
-                entry.rxPackets = reader.nextLong();
-                entry.txBytes = reader.nextLong();
-                entry.txPackets = reader.nextLong();
-
-                stats.insertEntry(entry);
-                reader.finishLine();
-            }
-        } catch (NullPointerException|NumberFormatException e) {
-            throw protocolExceptionWithCause("problem parsing stats", e);
-        } finally {
-            IoUtils.closeQuietly(reader);
-            StrictMode.setThreadPolicy(savedPolicy);
-        }
-        return stats;
+        return mDeps.getNetworkStatsDev();
     }
 
     public NetworkStats readNetworkStatsDetail() throws IOException {
@@ -364,33 +253,14 @@
             // Take a defensive copy. mPersistSnapshot is mutated in some cases below
             final NetworkStats prev = mPersistSnapshot.clone();
 
-            if (USE_NATIVE_PARSING) {
-                if (mUseBpfStats) {
-                    requestSwapActiveStatsMapLocked();
-                    // Stats are always read from the inactive map, so they must be read after the
-                    // swap
-                    final NetworkStats stats = mDeps.getNetworkStatsDetail(null /* path */, UID_ALL,
-                            INTERFACES_ALL, TAG_ALL, true /* useBpfStats */);
-
-                    // BPF stats are incremental; fold into mPersistSnapshot.
-                    mPersistSnapshot.setElapsedRealtime(stats.getElapsedRealtime());
-                    mPersistSnapshot.combineAllValues(stats);
-                } else {
-                    final NetworkStats stats = mDeps.getNetworkStatsDetail(
-                            mStatsXtUid.getAbsolutePath(), UID_ALL,
-                            INTERFACES_ALL, TAG_ALL, false /* useBpfStats */);
-                    if (VALIDATE_NATIVE_STATS) {
-                        final NetworkStats javaStats = javaReadNetworkStatsDetail(mStatsXtUid,
-                                UID_ALL, INTERFACES_ALL, TAG_ALL);
-                        assertEquals(javaStats, stats);
-                    }
-
-                    mPersistSnapshot = stats;
-                }
-            } else {
-                mPersistSnapshot = javaReadNetworkStatsDetail(mStatsXtUid, UID_ALL, INTERFACES_ALL,
-                        TAG_ALL);
-            }
+            requestSwapActiveStatsMapLocked();
+            // Stats are always read from the inactive map, so they must be read after the
+            // swap
+            final NetworkStats stats = mDeps.getNetworkStatsDetail(
+                    UID_ALL, INTERFACES_ALL, TAG_ALL);
+            // BPF stats are incremental; fold into mPersistSnapshot.
+            mPersistSnapshot.setElapsedRealtime(stats.getElapsedRealtime());
+            mPersistSnapshot.combineAllValues(stats);
 
             NetworkStats adjustedStats = adjustForTunAnd464Xlat(mPersistSnapshot, prev, vpnArray);
 
@@ -427,62 +297,6 @@
         return mTunAnd464xlatAdjustedStats.clone();
     }
 
-    /**
-     * Parse and return {@link NetworkStats} with UID-level details. Values are
-     * expected to monotonically increase since device boot.
-     */
-    @VisibleForTesting
-    public static NetworkStats javaReadNetworkStatsDetail(File detailPath, int limitUid,
-            String[] limitIfaces, int limitTag)
-            throws IOException {
-        final StrictMode.ThreadPolicy savedPolicy = StrictMode.allowThreadDiskReads();
-
-        final NetworkStats stats = new NetworkStats(SystemClock.elapsedRealtime(), 24);
-        final NetworkStats.Entry entry = new NetworkStats.Entry();
-
-        int idx = 1;
-        int lastIdx = 1;
-
-        ProcFileReader reader = null;
-        try {
-            // open and consume header line
-            reader = new ProcFileReader(new FileInputStream(detailPath));
-            reader.finishLine();
-
-            while (reader.hasMoreData()) {
-                idx = reader.nextInt();
-                if (idx != lastIdx + 1) {
-                    throw new ProtocolException(
-                            "inconsistent idx=" + idx + " after lastIdx=" + lastIdx);
-                }
-                lastIdx = idx;
-
-                entry.iface = reader.nextString();
-                entry.tag = kernelToTag(reader.nextString());
-                entry.uid = reader.nextInt();
-                entry.set = reader.nextInt();
-                entry.rxBytes = reader.nextLong();
-                entry.rxPackets = reader.nextLong();
-                entry.txBytes = reader.nextLong();
-                entry.txPackets = reader.nextLong();
-
-                if ((limitIfaces == null || CollectionUtils.contains(limitIfaces, entry.iface))
-                        && (limitUid == UID_ALL || limitUid == entry.uid)
-                        && (limitTag == TAG_ALL || limitTag == entry.tag)) {
-                    stats.insertEntry(entry);
-                }
-
-                reader.finishLine();
-            }
-        } catch (NullPointerException|NumberFormatException e) {
-            throw protocolExceptionWithCause("problem parsing idx " + idx, e);
-        } finally {
-            IoUtils.closeQuietly(reader);
-            StrictMode.setThreadPolicy(savedPolicy);
-        }
-
-        return stats;
-    }
 
     public void assertEquals(NetworkStats expected, NetworkStats actual) {
         if (expected.size() != actual.size()) {
diff --git a/tests/unit/java/com/android/server/net/NetworkStatsFactoryTest.java b/tests/unit/java/com/android/server/net/NetworkStatsFactoryTest.java
index 8f47e1f..14455fa 100644
--- a/tests/unit/java/com/android/server/net/NetworkStatsFactoryTest.java
+++ b/tests/unit/java/com/android/server/net/NetworkStatsFactoryTest.java
@@ -34,7 +34,6 @@
 import static org.junit.Assert.assertEquals;
 import static org.junit.Assert.fail;
 import static org.mockito.ArgumentMatchers.any;
-import static org.mockito.ArgumentMatchers.anyBoolean;
 import static org.mockito.ArgumentMatchers.anyInt;
 import static org.mockito.Mockito.doReturn;
 
@@ -90,7 +89,7 @@
         // related to networkStatsFactory is compiled to a minimal native library and loaded here.
         System.loadLibrary("networkstatsfactorytestjni");
         doReturn(mBpfNetMaps).when(mDeps).createBpfNetMaps(any());
-        mFactory = new NetworkStatsFactory(mContext, mTestProc, true, mDeps);
+        mFactory = new NetworkStatsFactory(mContext, mDeps);
         mFactory.updateUnderlyingNetworkInfos(new UnderlyingNetworkInfo[0]);
     }
 
@@ -533,8 +532,8 @@
         final NetworkStats statsFromResource = parseNetworkStatsFromGoldenSample(resourceId,
                 24 /* initialSize */, true /* consumeHeader */, false /* checkActive */,
                 true /* isUidData */);
-        doReturn(statsFromResource).when(mDeps).getNetworkStatsDetail(any(), anyInt(), any(),
-                anyInt(), anyBoolean());
+        doReturn(statsFromResource).when(mDeps).getNetworkStatsDetail(anyInt(), any(),
+                anyInt());
         return mFactory.readNetworkStatsDetail();
     }