add TCP data stall metrics

Current metrics contains only DNS signal. Given TCP info is
also considered to detection data stall, the related TCP
information should be included into metrics.

Bug: 150182763
Test: atest NetworkStackTests NetworkStackNextTests
Test: Test with ./out/host/linux-x86/bin/statsd_testdrive 121
      to ensure log properly
Merged-In: I5e306299f3cf4f49c46f161cd0aa4cb40d1ab76e
Change-Id: I5e306299f3cf4f49c46f161cd0aa4cb40d1ab76e

4 files changed, 138 insertions, 31 deletions

diff --git a/src/android/net/util/DataStallUtils.java b/src/android/net/util/DataStallUtils.java
index 5787879..3391a71 100644
--- a/src/android/net/util/DataStallUtils.java
+++ b/src/android/net/util/DataStallUtils.java
@@ -16,15 +16,30 @@
 
 package android.net.util;
 
+import android.annotation.IntDef;
+
+import java.lang.annotation.Retention;
+import java.lang.annotation.RetentionPolicy;
+
 /**
  * Collection of utilities for data stall.
  */
 public class DataStallUtils {
+    public static final int DATA_STALL_EVALUATION_TYPE_NONE = 0;
     /** Detect data stall using dns timeout counts. */
     public static final int DATA_STALL_EVALUATION_TYPE_DNS = 1 << 0;
     /** Detect data stall using tcp connection fail rate. */
     public static final int DATA_STALL_EVALUATION_TYPE_TCP = 1 << 1;
 
+    @IntDef(prefix = { "DATA_STALL_EVALUATION_TYPE_" }, value = {
+        DATA_STALL_EVALUATION_TYPE_NONE,
+        DATA_STALL_EVALUATION_TYPE_DNS,
+        DATA_STALL_EVALUATION_TYPE_TCP,
+    })
+    @Retention(RetentionPolicy.SOURCE)
+    public @interface EvaluationType {
+    }
+
     // Default configuration values for data stall detection.
     public static final int DEFAULT_CONSECUTIVE_DNS_TIMEOUT_THRESHOLD = 5;
     public static final int DEFAULT_DATA_STALL_MIN_EVALUATE_TIME_MS = 60 * 1000;
diff --git a/src/com/android/networkstack/metrics/DataStallDetectionStats.java b/src/com/android/networkstack/metrics/DataStallDetectionStats.java
index 7a1f9ac..d294e04 100644
--- a/src/com/android/networkstack/metrics/DataStallDetectionStats.java
+++ b/src/com/android/networkstack/metrics/DataStallDetectionStats.java
@@ -19,8 +19,10 @@ package com.android.networkstack.metrics;
 import android.net.util.NetworkStackUtils;
 import android.net.wifi.WifiInfo;
 
+import androidx.annotation.IntRange;
 import androidx.annotation.NonNull;
 import androidx.annotation.Nullable;
+import androidx.annotation.VisibleForTesting;
 
 import com.android.internal.util.HexDump;
 import com.android.server.connectivity.nano.CellularData;
@@ -41,18 +43,35 @@ import java.util.Objects;
  * @hide
  */
 public final class DataStallDetectionStats {
-    private static final int UNKNOWN_SIGNAL_STRENGTH = -1;
+    public static final int UNKNOWN_SIGNAL_STRENGTH = -1;
+    // Default value of TCP signals.
+    @VisibleForTesting
+    public static final int UNSPECIFIED_TCP_FAIL_RATE = -1;
+    @VisibleForTesting
+    public static final int UNSPECIFIED_TCP_PACKETS_COUNT = -1;
+    @VisibleForTesting
     @NonNull
-    final byte[] mCellularInfo;
+    public final byte[] mCellularInfo;
+    @VisibleForTesting
     @NonNull
-    final byte[] mWifiInfo;
+    public final byte[] mWifiInfo;
     @NonNull
-    final byte[] mDns;
-    final int mEvaluationType;
-    final int mNetworkType;
+    public final byte[] mDns;
+    @VisibleForTesting
+    public final int mEvaluationType;
+    @VisibleForTesting
+    public final int mNetworkType;
+    // The TCP packets fail rate percentage from the latest tcp polling. -1 means the TCP signal is
+    // not known or not supported on the SDK version of this device.
+    @VisibleForTesting @IntRange(from = -1, to = 100)
+    public final int mTcpFailRate;
+    // Number of packets sent since the last received packet.
+    @VisibleForTesting
+    public final int mTcpSentSinceLastRecv;
 
     public DataStallDetectionStats(@Nullable byte[] cell, @Nullable byte[] wifi,
-                @NonNull int[] returnCode, @NonNull long[] dnsTime, int evalType, int netType) {
+                @NonNull int[] returnCode, @NonNull long[] dnsTime, int evalType, int netType,
+                int failRate, int sentSinceLastRecv) {
         mCellularInfo = emptyCellDataIfNull(cell);
         mWifiInfo = emptyWifiInfoIfNull(wifi);
 
@@ -62,9 +81,20 @@ public final class DataStallDetectionStats {
         mDns = MessageNano.toByteArray(dns);
         mEvaluationType = evalType;
         mNetworkType = netType;
+        mTcpFailRate = failRate;
+        mTcpSentSinceLastRecv = sentSinceLastRecv;
     }
 
-    private byte[] emptyCellDataIfNull(@Nullable byte[] cell) {
+    /**
+     * Because metrics data must contain data for each field even if it's not supported or not
+     * available, generate a byte array representing an empty {@link CellularData} if the
+     * {@link CellularData} is unavailable.
+     *
+     * @param cell a byte array representing current {@link CellularData} of {@code this}
+     * @return a byte array of a {@link CellularData}.
+     */
+    @VisibleForTesting
+    public static byte[] emptyCellDataIfNull(@Nullable byte[] cell) {
         if (cell != null) return cell;
 
         CellularData data  = new CellularData();
@@ -75,7 +105,16 @@ public final class DataStallDetectionStats {
         return MessageNano.toByteArray(data);
     }
 
-    private byte[] emptyWifiInfoIfNull(@Nullable byte[] wifi) {
+    /**
+     * Because metrics data must contain data for each field even if it's not supported or not
+     * available, generate a byte array representing an empty {@link WifiData} if the
+     * {@link WiFiData} is unavailable.
+     *
+     * @param wifi a byte array representing current {@link WiFiData} of {@code this}.
+     * @return a byte array of a {@link WiFiData}.
+     */
+    @VisibleForTesting
+    public static byte[] emptyWifiInfoIfNull(@Nullable byte[] wifi) {
         if (wifi != null) return wifi;
 
         WifiData data = new WifiData();
@@ -95,7 +134,11 @@ public final class DataStallDetectionStats {
           .append(", cell info: ")
           .append(HexDump.toHexString(mCellularInfo))
           .append(", dns: ")
-          .append(HexDump.toHexString(mDns));
+          .append(HexDump.toHexString(mDns))
+          .append(", tcp fail rate: ")
+          .append(mTcpFailRate)
+          .append(", tcp received: ")
+          .append(mTcpSentSinceLastRecv);
         return sb.toString();
     }
 
@@ -107,12 +150,15 @@ public final class DataStallDetectionStats {
             && (mEvaluationType == other.mEvaluationType)
             && Arrays.equals(mWifiInfo, other.mWifiInfo)
             && Arrays.equals(mCellularInfo, other.mCellularInfo)
-            && Arrays.equals(mDns, other.mDns);
+            && Arrays.equals(mDns, other.mDns)
+            && (mTcpFailRate == other.mTcpFailRate)
+            && (mTcpSentSinceLastRecv == other.mTcpSentSinceLastRecv);
     }
 
     @Override
     public int hashCode() {
-        return Objects.hash(mNetworkType, mEvaluationType, mWifiInfo, mCellularInfo, mDns);
+        return Objects.hash(mNetworkType, mEvaluationType, mWifiInfo, mCellularInfo, mDns,
+                mTcpFailRate, mTcpSentSinceLastRecv);
     }
 
     /**
@@ -131,6 +177,8 @@ public final class DataStallDetectionStats {
         private final List<Long> mDnsTimeStamp = new ArrayList<Long>();
         private int mEvaluationType;
         private int mNetworkType;
+        private int mTcpFailRate = UNSPECIFIED_TCP_FAIL_RATE;
+        private int mTcpSentSinceLastRecv = UNSPECIFIED_TCP_PACKETS_COUNT;
 
         /**
          * Add a dns event into Builder.
@@ -168,6 +216,34 @@ public final class DataStallDetectionStats {
         }
 
         /**
+         * Set the TCP packet fail rate into Builder. The data is included since android R.
+         *
+         * @param rate the TCP packet fail rate of the logged network. The default value is
+         *               {@code UNSPECIFIED_TCP_FAIL_RATE}, which means the TCP signal is not known
+         *               or not supported on the SDK version of this device.
+         * @return {@code this} {@link Builder} instance.
+         */
+        public Builder setTcpFailRate(@IntRange(from = -1, to = 100) int rate) {
+            mTcpFailRate = rate;
+            return this;
+        }
+
+        /**
+         * Set the number of TCP packets sent since the last received packet into Builder. The data
+         * starts to be included since android R.
+         *
+         * @param count the number of packets sent since the last received packet of the logged
+         *              network. Keep it unset as default value or set to
+         *              {@code UNSPECIFIED_TCP_PACKETS_COUNT} if the tcp signal is unsupported with
+         *              current device android sdk version or the packets count is unknown.
+         * @return {@code this} {@link Builder} instance.
+         */
+        public Builder setTcpSentSinceLastRecv(int count) {
+            mTcpSentSinceLastRecv = count;
+            return this;
+        }
+
+        /**
          * Set the wifi data into Builder.
          *
          * @param info a {@link WifiInfo} of the connected wifi network.
@@ -223,7 +299,7 @@ public final class DataStallDetectionStats {
             return new DataStallDetectionStats(mCellularInfo, mWifiInfo,
                     NetworkStackUtils.convertToIntArray(mDnsReturnCode),
                     NetworkStackUtils.convertToLongArray(mDnsTimeStamp),
-                    mEvaluationType, mNetworkType);
+                    mEvaluationType, mNetworkType, mTcpFailRate, mTcpSentSinceLastRecv);
         }
     }
 }
diff --git a/src/com/android/networkstack/metrics/DataStallStatsUtils.java b/src/com/android/networkstack/metrics/DataStallStatsUtils.java
index e7a6c3d..c0719c0 100644
--- a/src/com/android/networkstack/metrics/DataStallStatsUtils.java
+++ b/src/com/android/networkstack/metrics/DataStallStatsUtils.java
@@ -74,6 +74,8 @@ public class DataStallStatsUtils {
                 stats.mNetworkType,
                 stats.mWifiInfo,
                 stats.mCellularInfo,
-                stats.mDns);
+                stats.mDns,
+                stats.mTcpFailRate,
+                stats.mTcpSentSinceLastRecv);
     }
 }
diff --git a/src/com/android/server/connectivity/NetworkMonitor.java b/src/com/android/server/connectivity/NetworkMonitor.java
index 7fb6761..093118a 100755
--- a/src/com/android/server/connectivity/NetworkMonitor.java
+++ b/src/com/android/server/connectivity/NetworkMonitor.java
@@ -48,6 +48,7 @@ import static android.net.util.DataStallUtils.CONFIG_DATA_STALL_MIN_EVALUATE_INT
 import static android.net.util.DataStallUtils.CONFIG_DATA_STALL_TCP_POLLING_INTERVAL;
 import static android.net.util.DataStallUtils.CONFIG_DATA_STALL_VALID_DNS_TIME_THRESHOLD;
 import static android.net.util.DataStallUtils.DATA_STALL_EVALUATION_TYPE_DNS;
+import static android.net.util.DataStallUtils.DATA_STALL_EVALUATION_TYPE_NONE;
 import static android.net.util.DataStallUtils.DATA_STALL_EVALUATION_TYPE_TCP;
 import static android.net.util.DataStallUtils.DEFAULT_CONSECUTIVE_DNS_TIMEOUT_THRESHOLD;
 import static android.net.util.DataStallUtils.DEFAULT_DATA_STALL_EVALUATION_TYPES;
@@ -112,6 +113,7 @@ import android.net.metrics.NetworkEvent;
 import android.net.metrics.ValidationProbeEvent;
 import android.net.shared.NetworkMonitorUtils;
 import android.net.shared.PrivateDnsConfig;
+import android.net.util.DataStallUtils.EvaluationType;
 import android.net.util.NetworkStackUtils;
 import android.net.util.SharedLog;
 import android.net.util.Stopwatch;
@@ -489,8 +491,8 @@ public class NetworkMonitor extends StateMachine {
     @Nullable
     private final DnsStallDetector mDnsStallDetector;
     private long mLastProbeTime;
-    // Set to true if data stall is suspected and reset to false after metrics are sent to statsd.
-    private boolean mCollectDataStallMetrics;
+    // The signal causing a data stall to be suspected. Reset to 0 after metrics are sent to statsd.
+    private @EvaluationType int mDataStallTypeToCollect;
     private boolean mAcceptPartialConnectivity = false;
     private final EvaluationState mEvaluationState = new EvaluationState();
 
@@ -977,8 +979,6 @@ public class NetworkMonitor extends StateMachine {
 
         boolean evaluateDataStall() {
             if (isDataStall()) {
-                // TODO: Add tcp info into metrics.
-                mCollectDataStallMetrics = true;
                 validationLog("Suspecting data stall, reevaluate");
                 return true;
             }
@@ -999,7 +999,8 @@ public class NetworkMonitor extends StateMachine {
         }
     }
 
-    private void writeDataStallStats(@NonNull final CaptivePortalProbeResult result) {
+    private void maybeWriteDataStallStats(@NonNull final CaptivePortalProbeResult result) {
+        if (mDataStallTypeToCollect == DATA_STALL_EVALUATION_TYPE_NONE) return;
         /*
          * Collect data stall detection level information for each transport type. Collect type
          * specific information for cellular and wifi only currently. Generate
@@ -1007,19 +1008,22 @@ public class NetworkMonitor extends StateMachine {
          * TRANSPORT_WIFI and TRANSPORT_VPN, two DataStallDetectionStats will be generated.
          */
         final int[] transports = mNetworkCapabilities.getTransportTypes();
-
         for (int i = 0; i < transports.length; i++) {
-            final DataStallDetectionStats stats = buildDataStallDetectionStats(transports[i]);
+            final DataStallDetectionStats stats =
+                    buildDataStallDetectionStats(transports[i], mDataStallTypeToCollect);
             mDependencies.writeDataStallDetectionStats(stats, result);
         }
-        mCollectDataStallMetrics = false;
+        mDataStallTypeToCollect = DATA_STALL_EVALUATION_TYPE_NONE;
     }
 
     @VisibleForTesting
-    protected DataStallDetectionStats buildDataStallDetectionStats(int transport) {
+    protected DataStallDetectionStats buildDataStallDetectionStats(int transport,
+            @EvaluationType int evaluationType) {
         final DataStallDetectionStats.Builder stats = new DataStallDetectionStats.Builder();
-        if (VDBG_STALL) log("collectDataStallMetrics: type=" + transport);
-        stats.setEvaluationType(DATA_STALL_EVALUATION_TYPE_DNS);
+        if (VDBG_STALL) {
+            log("collectDataStallMetrics: type=" + transport + ", evaluation=" + evaluationType);
+        }
+        stats.setEvaluationType(evaluationType);
         stats.setNetworkType(transport);
         switch (transport) {
             case NetworkCapabilities.TRANSPORT_WIFI:
@@ -1044,11 +1048,21 @@ public class NetworkMonitor extends StateMachine {
                 // No transport type specific information for the other types.
                 break;
         }
+
         addDnsEvents(stats);
+        addTcpStats(stats);
 
         return stats.build();
     }
 
+    private void addTcpStats(@NonNull final DataStallDetectionStats.Builder stats) {
+        final TcpSocketTracker tst = getTcpSocketTracker();
+        if (tst == null) return;
+
+        stats.setTcpSentSinceLastRecv(tst.getSentSinceLastRecv());
+        stats.setTcpFailRate(tst.getLatestPacketFailPercentage());
+    }
+
     @VisibleForTesting
     protected void addDnsEvents(@NonNull final DataStallDetectionStats.Builder stats) {
         final DnsStallDetector dsd = getDnsStallDetector();
@@ -1438,9 +1452,7 @@ public class NetworkMonitor extends StateMachine {
                             (CaptivePortalProbeResult) message.obj;
                     mLastProbeTime = SystemClock.elapsedRealtime();
 
-                    if (mCollectDataStallMetrics) {
-                        writeDataStallStats(probeResult);
-                    }
+                    maybeWriteDataStallStats(probeResult);
 
                     if (probeResult.isSuccessful()) {
                         // Transit EvaluatingPrivateDnsState to get to Validated
@@ -1919,7 +1931,8 @@ public class NetworkMonitor extends StateMachine {
                 DEFAULT_DATA_STALL_VALID_DNS_TIME_THRESHOLD_MS);
     }
 
-    private int getDataStallEvaluationType() {
+    @VisibleForTesting
+    int getDataStallEvaluationType() {
         return mDependencies.getDeviceConfigPropertyInt(NAMESPACE_CONNECTIVITY,
                 CONFIG_DATA_STALL_EVALUATION_TYPE,
                 DEFAULT_DATA_STALL_EVALUATION_TYPES);
@@ -3140,9 +3153,8 @@ public class NetworkMonitor extends StateMachine {
         return mDnsStallDetector;
     }
 
-    @VisibleForTesting
     @Nullable
-    protected TcpSocketTracker getTcpSocketTracker() {
+    private TcpSocketTracker getTcpSocketTracker() {
         return mTcpTracker;
     }
 
@@ -3179,6 +3191,7 @@ public class NetworkMonitor extends StateMachine {
                 result = false;
             } else if (tst.isDataStallSuspected()) {
                 result = true;
+                mDataStallTypeToCollect = DATA_STALL_EVALUATION_TYPE_TCP;
 
                 final DataStallReportParcelable p = new DataStallReportParcelable();
                 p.detectionMethod = DETECTION_METHOD_TCP_METRICS;
@@ -3203,6 +3216,7 @@ public class NetworkMonitor extends StateMachine {
             if (dsd.isDataStallSuspected(mConsecutiveDnsTimeoutThreshold,
                     mDataStallValidDnsTimeThreshold)) {
                 result = true;
+                mDataStallTypeToCollect = DATA_STALL_EVALUATION_TYPE_DNS;
                 logNetworkEvent(NetworkEvent.NETWORK_CONSECUTIVE_DNS_TIMEOUT_FOUND);
 
                 final DataStallReportParcelable p = new DataStallReportParcelable();