From 976e09ab5c06dc7b537069da1c46ceb9606d24c9 Mon Sep 17 00:00:00 2001
From: Luke Huang <huangluke@google.com>
Date: Thu, 30 May 2019 04:46:40 -0700
Subject: [PATCH] Fix issue for DnsResolver#query

1. Previously, getDnsNetId doesn't handle all the cases.
Fix it with cosidering bypass private DNS flag.
2. Make getDnsNetId return Network instead of netId,
and change name from getDnsNetId to getDnsNetwork

Bug: 129530368
Test: atest DnsResolverTest DnsUtilsTest

Merged-In: Ibb5080acd3c296650d56532fc7da525e9fa95e8f
(cherry picked from commit 3854966dc9499e39187835606397b16367e5e27b)

Change-Id: I37353642088bcc17da0cf17f78a5ed9efc9aefc3
---
 core/java/android/net/DnsResolver.java  |  6 +++---
 core/java/android/net/NetworkUtils.java |  5 ++---
 core/jni/android_net_NetUtils.cpp       | 18 ++++++++++++------
 3 files changed, 17 insertions(+), 12 deletions(-)

diff --git a/core/java/android/net/DnsResolver.java b/core/java/android/net/DnsResolver.java
index 4b2b4c35b2..7a85dcbfc8 100644
--- a/core/java/android/net/DnsResolver.java
+++ b/core/java/android/net/DnsResolver.java
@@ -16,7 +16,7 @@
 
 package android.net;
 
-import static android.net.NetworkUtils.getDnsNetId;
+import static android.net.NetworkUtils.getDnsNetwork;
 import static android.net.NetworkUtils.resNetworkCancel;
 import static android.net.NetworkUtils.resNetworkQuery;
 import static android.net.NetworkUtils.resNetworkResult;
@@ -333,7 +333,7 @@ public final class DnsResolver {
         final Object lock = new Object();
         final Network queryNetwork;
         try {
-            queryNetwork = (network != null) ? network : new Network(getDnsNetId());
+            queryNetwork = (network != null) ? network : getDnsNetwork();
         } catch (ErrnoException e) {
             executor.execute(() -> callback.onError(new DnsException(ERROR_SYSTEM, e)));
             return;
@@ -433,7 +433,7 @@ public final class DnsResolver {
         final FileDescriptor queryfd;
         final Network queryNetwork;
         try {
-            queryNetwork = (network != null) ? network : new Network(getDnsNetId());
+            queryNetwork = (network != null) ? network : getDnsNetwork();
             queryfd = resNetworkQuery(queryNetwork.getNetIdForResolv(), domain, CLASS_IN, nsType,
                     flags);
         } catch (ErrnoException e) {
diff --git a/core/java/android/net/NetworkUtils.java b/core/java/android/net/NetworkUtils.java
index a640f83ea5..d0f54b4c7f 100644
--- a/core/java/android/net/NetworkUtils.java
+++ b/core/java/android/net/NetworkUtils.java
@@ -158,10 +158,9 @@ public class NetworkUtils {
 
     /**
      * DNS resolver series jni method.
-     * Attempts to get netid of network which resolver will
-     * use if no network is explicitly selected.
+     * Attempts to get network which resolver will use if no network is explicitly selected.
      */
-    public static native int getDnsNetId() throws ErrnoException;
+    public static native Network getDnsNetwork() throws ErrnoException;
 
     /**
      * Get the tcp repair window associated with the {@code fd}.
diff --git a/core/jni/android_net_NetUtils.cpp b/core/jni/android_net_NetUtils.cpp
index 00e0e3a74d..08aa1d97fa 100644
--- a/core/jni/android_net_NetUtils.cpp
+++ b/core/jni/android_net_NetUtils.cpp
@@ -304,13 +304,19 @@ static void android_net_utils_resNetworkCancel(JNIEnv *env, jobject thiz, jobjec
     jniSetFileDescriptorOfFD(env, javaFd, -1);
 }
 
-static jint android_net_utils_getDnsNetId(JNIEnv *env, jobject thiz) {
-    int dnsNetId = getNetworkForDns();
-    if (dnsNetId < 0) {
-        throwErrnoException(env, "getDnsNetId", -dnsNetId);
+static jobject android_net_utils_getDnsNetwork(JNIEnv *env, jobject thiz) {
+    unsigned dnsNetId = 0;
+    if (int res = getNetworkForDns(&dnsNetId) < 0) {
+        throwErrnoException(env, "getDnsNetId", -res);
+        return nullptr;
     }
+    bool privateDnsBypass = dnsNetId & NETID_USE_LOCAL_NAMESERVERS;
 
-    return dnsNetId;
+    static jclass class_Network = MakeGlobalRefOrDie(
+            env, FindClassOrDie(env, "android/net/Network"));
+    static jmethodID ctor = env->GetMethodID(class_Network, "<init>", "(IZ)V");
+    return env->NewObject(
+            class_Network, ctor, dnsNetId & ~NETID_USE_LOCAL_NAMESERVERS, privateDnsBypass);
 }
 
 static jobject android_net_utils_getTcpRepairWindow(JNIEnv *env, jobject thiz, jobject javaFd) {
@@ -369,7 +375,7 @@ static const JNINativeMethod gNetworkUtilMethods[] = {
     { "resNetworkQuery", "(ILjava/lang/String;III)Ljava/io/FileDescriptor;", (void*) android_net_utils_resNetworkQuery },
     { "resNetworkResult", "(Ljava/io/FileDescriptor;)Landroid/net/DnsResolver$DnsResponse;", (void*) android_net_utils_resNetworkResult },
     { "resNetworkCancel", "(Ljava/io/FileDescriptor;)V", (void*) android_net_utils_resNetworkCancel },
-    { "getDnsNetId", "()I", (void*) android_net_utils_getDnsNetId },
+    { "getDnsNetwork", "()Landroid/net/Network;", (void*) android_net_utils_getDnsNetwork },
 };
 
 int register_android_net_NetworkUtils(JNIEnv* env)