From 5aee36bf7e0d93b2a1bbe4ddc6958aa414821303 Mon Sep 17 00:00:00 2001
From: Remi NGUYEN VAN <reminv@google.com>
Date: Sun, 21 Mar 2021 14:30:38 +0000
Subject: [PATCH] Add NDK API for getprocnetwork

The API is the getter couterpart for setprocnetwork.
Use it in NetworkUtils so that the NDK API can be the source of truth
for the process network.

Bug: 171540887
Test: atest CtsNetTestCases
      Tests in change I311b58585033c2ca50ce5477ea9cd94b6f127507
Change-Id: Ie8f68cf1fa57deddb63324c1abf3d6fd5b0ef500
---
 framework/Android.bp                        |  2 ++
 framework/jni/android_net_NetworkUtils.cpp  | 20 ++++++++++++++------
 framework/src/android/net/NetworkUtils.java | 15 +++++++++++++--
 3 files changed, 29 insertions(+), 8 deletions(-)

diff --git a/framework/Android.bp b/framework/Android.bp
index 657d5a3d2e..3553c1f053 100644
--- a/framework/Android.bp
+++ b/framework/Android.bp
@@ -128,6 +128,7 @@ cc_library_static {
     srcs: [
         "jni/android_net_NetworkUtils.cpp",
     ],
+    shared_libs: ["libandroid_net"],
     apex_available: [
         "//apex_available:platform",
         "com.android.tethering",
@@ -140,6 +141,7 @@ cc_library_shared {
     srcs: [
         "jni/onload.cpp",
     ],
+    shared_libs: ["libandroid"],
     static_libs: ["libconnectivityframeworkutils"],
     apex_available: [
         "//apex_available:platform",
diff --git a/framework/jni/android_net_NetworkUtils.cpp b/framework/jni/android_net_NetworkUtils.cpp
index 19ffe77c1f..89b058af69 100644
--- a/framework/jni/android_net_NetworkUtils.cpp
+++ b/framework/jni/android_net_NetworkUtils.cpp
@@ -19,6 +19,7 @@
 #include <vector>
 
 #include <android/file_descriptor_jni.h>
+#include <android/multinetwork.h>
 #include <arpa/inet.h>
 #include <linux/filter.h>
 #include <linux/if_arp.h>
@@ -122,14 +123,21 @@ static void android_net_utils_detachBPFFilter(JNIEnv *env, jobject clazz, jobjec
     }
 }
 
-static jboolean android_net_utils_bindProcessToNetwork(JNIEnv *env, jobject thiz, jint netId)
+static jboolean android_net_utils_bindProcessToNetworkHandle(JNIEnv *env, jobject thiz,
+        jlong netHandle)
 {
-    return (jboolean) !setNetworkForProcess(netId);
+    return (jboolean) !android_setprocnetwork(netHandle);
 }
 
-static jint android_net_utils_getBoundNetworkForProcess(JNIEnv *env, jobject thiz)
+static jlong android_net_utils_getBoundNetworkHandleForProcess(JNIEnv *env, jobject thiz)
 {
-    return getNetworkForProcess();
+    net_handle_t network;
+    if (android_getprocnetwork(&network) != 0) {
+        jniThrowExceptionFmt(env, "java/lang/IllegalStateException",
+                "android_getprocnetwork(): %s", strerror(errno));
+        return NETWORK_UNSPECIFIED;
+    }
+    return (jlong) network;
 }
 
 static jboolean android_net_utils_bindProcessToNetworkForHostResolution(JNIEnv *env, jobject thiz,
@@ -283,8 +291,8 @@ static jobject android_net_utils_getTcpRepairWindow(JNIEnv *env, jobject thiz, j
 // clang-format off
 static const JNINativeMethod gNetworkUtilMethods[] = {
     /* name, signature, funcPtr */
-    { "bindProcessToNetwork", "(I)Z", (void*) android_net_utils_bindProcessToNetwork },
-    { "getBoundNetworkForProcess", "()I", (void*) android_net_utils_getBoundNetworkForProcess },
+    { "bindProcessToNetworkHandle", "(J)Z", (void*) android_net_utils_bindProcessToNetworkHandle },
+    { "getBoundNetworkHandleForProcess", "()J", (void*) android_net_utils_getBoundNetworkHandleForProcess },
     { "bindProcessToNetworkForHostResolution", "(I)Z", (void*) android_net_utils_bindProcessToNetworkForHostResolution },
     { "bindSocketToNetwork", "(Ljava/io/FileDescriptor;I)I", (void*) android_net_utils_bindSocketToNetwork },
     { "queryUserAccess", "(II)Z", (void*)android_net_utils_queryUserAccess },
diff --git a/framework/src/android/net/NetworkUtils.java b/framework/src/android/net/NetworkUtils.java
index c0f262815b..4c61d4089d 100644
--- a/framework/src/android/net/NetworkUtils.java
+++ b/framework/src/android/net/NetworkUtils.java
@@ -16,6 +16,8 @@
 
 package android.net;
 
+import static android.net.ConnectivityManager.NETID_UNSET;
+
 import android.compat.annotation.UnsupportedAppUsage;
 import android.os.Build;
 import android.system.ErrnoException;
@@ -55,6 +57,8 @@ public class NetworkUtils {
      */
     public static native void detachBPFFilter(FileDescriptor fd) throws SocketException;
 
+    private static native boolean bindProcessToNetworkHandle(long netHandle);
+
     /**
      * Binds the current process to the network designated by {@code netId}.  All sockets created
      * in the future (and not explicitly bound via a bound {@link SocketFactory} (see
@@ -63,13 +67,20 @@ public class NetworkUtils {
      * is by design so an application doesn't accidentally use sockets it thinks are still bound to
      * a particular {@code Network}.  Passing NETID_UNSET clears the binding.
      */
-    public native static boolean bindProcessToNetwork(int netId);
+    public static boolean bindProcessToNetwork(int netId) {
+        return bindProcessToNetworkHandle(new Network(netId).getNetworkHandle());
+    }
+
+    private static native long getBoundNetworkHandleForProcess();
 
     /**
      * Return the netId last passed to {@link #bindProcessToNetwork}, or NETID_UNSET if
      * {@link #unbindProcessToNetwork} has been called since {@link #bindProcessToNetwork}.
      */
-    public native static int getBoundNetworkForProcess();
+    public static int getBoundNetworkForProcess() {
+        final long netHandle = getBoundNetworkHandleForProcess();
+        return netHandle == 0L ? NETID_UNSET : Network.fromNetworkHandle(netHandle).getNetId();
+    }
 
     /**
      * Binds host resolutions performed by this process to the network designated by {@code netId}.