Register network tracing in system_server after boot

This runs the Perfetto and NetworkTraceHandler initialization on system
initialization along with the existing NetworkStatsService. The code is
run within the context of the system_server and is only executed on U or
later devices running eng or userdebug builds.

Bug: 246985031
Test: build & flash
Change-Id: I2b091e31c3ded54c0d7062d7d73f33ed47e0bf98

Former-commit-id: 1b71b7f70b

service-t/jni/com_android_server_net_NetworkStatsService.cpp

@@ -30,9 +30,11 @@
 
 #include "bpf/BpfUtils.h"
 #include "netdbpf/BpfNetworkStats.h"
+#include "netdbpf/NetworkTraceHandler.h"
 
 using android::bpf::bpfGetUidStats;
 using android::bpf::bpfGetIfaceStats;
+using android::bpf::NetworkTraceHandler;
 
 namespace android {
 
@@ -67,7 +69,7 @@ static uint64_t getStatsType(Stats* stats, StatsType type) {
     }
 }
 
-static jlong getTotalStat(JNIEnv* env, jclass clazz, jint type) {
+static jlong nativeGetTotalStat(JNIEnv* env, jclass clazz, jint type) {
     Stats stats = {};
 
     if (bpfGetIfaceStats(NULL, &stats) == 0) {
@@ -77,7 +79,7 @@ static jlong getTotalStat(JNIEnv* env, jclass clazz, jint type) {
     }
 }
 
-static jlong getIfaceStat(JNIEnv* env, jclass clazz, jstring iface, jint type) {
+static jlong nativeGetIfaceStat(JNIEnv* env, jclass clazz, jstring iface, jint type) {
     ScopedUtfChars iface8(env, iface);
     if (iface8.c_str() == NULL) {
         return UNKNOWN;
@@ -92,7 +94,7 @@ static jlong getIfaceStat(JNIEnv* env, jclass clazz, jstring iface, jint type) {
     }
 }
 
-static jlong getUidStat(JNIEnv* env, jclass clazz, jint uid, jint type) {
+static jlong nativeGetUidStat(JNIEnv* env, jclass clazz, jint uid, jint type) {
     Stats stats = {};
 
     if (bpfGetUidStats(uid, &stats) == 0) {
@@ -102,10 +104,15 @@ static jlong getUidStat(JNIEnv* env, jclass clazz, jint uid, jint type) {
     }
 }
 
+static void nativeInitNetworkTracing(JNIEnv* env, jclass clazz) {
+    NetworkTraceHandler::InitPerfettoTracing();
+}
+
 static const JNINativeMethod gMethods[] = {
-        {"nativeGetTotalStat", "(I)J", (void*)getTotalStat},
-        {"nativeGetIfaceStat", "(Ljava/lang/String;I)J", (void*)getIfaceStat},
-        {"nativeGetUidStat", "(II)J", (void*)getUidStat},
+        {"nativeGetTotalStat", "(I)J", (void*)nativeGetTotalStat},
+        {"nativeGetIfaceStat", "(Ljava/lang/String;I)J", (void*)nativeGetIfaceStat},
+        {"nativeGetUidStat", "(II)J", (void*)nativeGetUidStat},
+        {"nativeInitNetworkTracing", "()V", (void*)nativeInitNetworkTracing},
 };
 
 int register_android_server_net_NetworkStatsService(JNIEnv* env) {

service-t/native/libs/libnetworkstats/NetworkTraceHandler.cpp

@@ -25,6 +25,7 @@
 #include <perfetto/trace/android/network_trace.pbzero.h>
 #include <perfetto/trace/profiling/profile_packet.pbzero.h>
 #include <perfetto/tracing/platform.h>
+#include <perfetto/tracing/tracing.h>
 
 // Note: this is initializing state for a templated Perfetto type that resides
 // in the `perfetto` namespace. This must be defined in the global scope.
@@ -45,6 +46,14 @@ void NetworkTraceHandler::RegisterDataSource() {
   NetworkTraceHandler::Register(dsd);
 }
 
+// static
+void NetworkTraceHandler::InitPerfettoTracing() {
+  perfetto::TracingInitArgs args = {};
+  args.backends |= perfetto::kSystemBackend;
+  perfetto::Tracing::Initialize(args);
+  NetworkTraceHandler::RegisterDataSource();
+}
+
 NetworkTraceHandler::NetworkTraceHandler()
     : NetworkTraceHandler([this](const PacketTrace& pkt) {
         NetworkTraceHandler::Trace(

service-t/native/libs/libnetworkstats/include/netdbpf/NetworkTraceHandler.h

@@ -36,6 +36,9 @@ class NetworkTraceHandler : public perfetto::DataSource<NetworkTraceHandler> {
   // Registers this DataSource.
   static void RegisterDataSource();
 
+  // Connects to the system Perfetto daemon and registers the trace handler.
+  static void InitPerfettoTracing();
+
   // Initialize with the default Perfetto callback.
   NetworkTraceHandler();
 

service-t/src/com/android/server/NetworkStatsServiceInitializer.java

@@ -18,6 +18,7 @@ package com.android.server;
 
 import android.content.Context;
 import android.net.TrafficStats;
+import android.os.Build;
 import android.util.Log;
 
 import com.android.modules.utils.build.SdkLevel;
@@ -46,6 +47,15 @@ public final class NetworkStatsServiceInitializer extends SystemService {
                     /* allowIsolated= */ false);
             TrafficStats.init(getContext());
         }
+
+        // The following code registers the Perfetto Network Trace Handler on non-user builds.
+        // The enhanced tracing is intended to be used for debugging and diagnosing issues. This
+        // is conditional on the build type rather than `isDebuggable` to match the system_server
+        // selinux rules which only allow the Perfetto connection under the same circumstances.
+        if (SdkLevel.isAtLeastU() && !Build.TYPE.equals("user")) {
+            Log.i(TAG, "Initializing network tracing hooks");
+            NetworkStatsService.nativeInitNetworkTracing();
+        }
     }
 
     @Override

service-t/src/com/android/server/net/NetworkStatsService.java

@@ -3269,4 +3269,7 @@ public class NetworkStatsService extends INetworkStatsService.Stub {
     private static native long nativeGetTotalStat(int type);
     private static native long nativeGetIfaceStat(String iface, int type);
     private static native long nativeGetUidStat(int uid, int type);
+
+    /** Initializes and registers the Perfetto Network Trace data source */
+    public static native void nativeInitNetworkTracing();
 }