Use async dns query to resolve all addresses

Currently, it looks like private DNS server resolution uses
OneAddressPerFamilyNetwork and only returns one server address.
It should return all addresses. Use async dns api for this.

Bug: 123435238
Test: atest NetworkStacktests

Change-Id: I2b7e184d9b9800a83b55dceb73af69085668748c
(cherry picked from commit 40c5295cee38166fadb53d5f37dc885d94c4971f)
Merged-In: I2b7e184d9b9800a83b55dceb73af69085668748c
Merged-In: I9f50da3c8c2e3b12b29bc8844291e4bf1559cd1f

2 files changed, 127 insertions, 36 deletions

diff --git a/src/com/android/networkstack/util/DnsUtils.java b/src/com/android/networkstack/util/DnsUtils.java
new file mode 100644
index 0000000..85f94e1
--- /dev/null
+++ b/src/com/android/networkstack/util/DnsUtils.java
@@ -0,0 +1,119 @@
+/*
+ * Copyright (C) 2019 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.android.networkstack.util;
+
+import static android.net.DnsResolver.FLAG_NO_CACHE_LOOKUP;
+import static android.net.DnsResolver.TYPE_A;
+import static android.net.DnsResolver.TYPE_AAAA;
+
+import android.annotation.NonNull;
+import android.net.DnsResolver;
+import android.net.Network;
+import android.net.TrafficStats;
+import android.util.Log;
+
+import com.android.internal.util.TrafficStatsConstants;
+
+import java.net.InetAddress;
+import java.net.UnknownHostException;
+import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.List;
+import java.util.concurrent.CountDownLatch;
+import java.util.concurrent.TimeUnit;
+import java.util.concurrent.atomic.AtomicReference;
+
+/**
+ * Collection of utilities for dns query.
+ */
+public class DnsUtils {
+    // Decide what queries to make depending on what IP addresses are on the system.
+    public static final int TYPE_ADDRCONFIG = -1;
+    private static final String TAG = DnsUtils.class.getSimpleName();
+
+    /**
+     * Return both A and AAAA query results regardless the ip address type of the giving network.
+     * Used for probing in NetworkMonitor.
+     */
+    @NonNull
+    public static InetAddress[] getAllByName(@NonNull final DnsResolver dnsResolver,
+            @NonNull final Network network, @NonNull String host, int timeout)
+            throws UnknownHostException {
+        final List<InetAddress> result = new ArrayList<InetAddress>();
+
+        result.addAll(Arrays.asList(
+                getAllByName(dnsResolver, network, host, TYPE_AAAA, FLAG_NO_CACHE_LOOKUP,
+                timeout)));
+        result.addAll(Arrays.asList(
+                getAllByName(dnsResolver, network, host, TYPE_A, FLAG_NO_CACHE_LOOKUP,
+                timeout)));
+        return result.toArray(new InetAddress[0]);
+    }
+
+    /**
+     * Return dns query result based on the given QueryType(TYPE_A, TYPE_AAAA) or TYPE_ADDRCONFIG.
+     * Used for probing in NetworkMonitor.
+     */
+    @NonNull
+    public static InetAddress[] getAllByName(@NonNull final DnsResolver dnsResolver,
+            @NonNull final Network network, @NonNull final String host, int type, int flag,
+            int timeoutMs) throws UnknownHostException {
+        final CountDownLatch latch = new CountDownLatch(1);
+        final AtomicReference<List<InetAddress>> resultRef = new AtomicReference<>();
+
+        final DnsResolver.Callback<List<InetAddress>> callback =
+                new DnsResolver.Callback<List<InetAddress>>() {
+            @Override
+            public void onAnswer(List<InetAddress> answer, int rcode) {
+                if (rcode == 0) {
+                    resultRef.set(answer);
+                }
+                latch.countDown();
+            }
+
+            @Override
+            public void onError(@NonNull DnsResolver.DnsException e) {
+                Log.d(TAG, "DNS error resolving " + host + ": " + e.getMessage());
+                latch.countDown();
+            }
+        };
+        final int oldTag = TrafficStats.getAndSetThreadStatsTag(
+                TrafficStatsConstants.TAG_SYSTEM_PROBE);
+
+        if (type == TYPE_ADDRCONFIG) {
+            dnsResolver.query(network, host, flag, r -> r.run(), null /* cancellationSignal */,
+                    callback);
+        } else {
+            dnsResolver.query(network, host, type, flag, r -> r.run(),
+                    null /* cancellationSignal */, callback);
+        }
+
+        TrafficStats.setThreadStatsTag(oldTag);
+
+        try {
+            latch.await(timeoutMs, TimeUnit.MILLISECONDS);
+        } catch (InterruptedException e) {
+        }
+
+        final List<InetAddress> result = resultRef.get();
+        if (result == null || result.size() == 0) {
+            throw new UnknownHostException(host);
+        }
+
+        return result.toArray(new InetAddress[0]);
+    }
+}
diff --git a/src/com/android/server/connectivity/NetworkMonitor.java b/src/com/android/server/connectivity/NetworkMonitor.java
index d6355bc..7bdf396 100644
--- a/src/com/android/server/connectivity/NetworkMonitor.java
+++ b/src/com/android/server/connectivity/NetworkMonitor.java
@@ -23,6 +23,7 @@ import static android.net.ConnectivityManager.EXTRA_CAPTIVE_PORTAL_PROBE_SPEC;
 import static android.net.ConnectivityManager.EXTRA_CAPTIVE_PORTAL_URL;
 import static android.net.ConnectivityManager.TYPE_MOBILE;
 import static android.net.ConnectivityManager.TYPE_WIFI;
+import static android.net.DnsResolver.FLAG_EMPTY;
 import static android.net.INetworkMonitor.NETWORK_TEST_RESULT_INVALID;
 import static android.net.INetworkMonitor.NETWORK_TEST_RESULT_PARTIAL_CONNECTIVITY;
 import static android.net.NetworkCapabilities.NET_CAPABILITY_NOT_METERED;
@@ -56,6 +57,8 @@ import static android.net.util.NetworkStackUtils.CAPTIVE_PORTAL_USE_HTTPS;
 import static android.net.util.NetworkStackUtils.NAMESPACE_CONNECTIVITY;
 import static android.net.util.NetworkStackUtils.isEmpty;
 
+import static com.android.networkstack.util.DnsUtils.TYPE_ADDRCONFIG;
+
 import android.annotation.NonNull;
 import android.annotation.Nullable;
 import android.app.PendingIntent;
@@ -113,6 +116,7 @@ import com.android.internal.util.TrafficStatsConstants;
 import com.android.networkstack.R;
 import com.android.networkstack.metrics.DataStallDetectionStats;
 import com.android.networkstack.metrics.DataStallStatsUtils;
+import com.android.networkstack.util.DnsUtils;
 
 import java.io.IOException;
 import java.net.HttpURLConnection;
@@ -129,7 +133,6 @@ import java.util.Random;
 import java.util.UUID;
 import java.util.concurrent.CountDownLatch;
 import java.util.concurrent.TimeUnit;
-import java.util.concurrent.atomic.AtomicReference;
 import java.util.function.Function;
 
 /**
@@ -994,8 +997,8 @@ public class NetworkMonitor extends StateMachine {
         private void resolveStrictModeHostname() {
             try {
                 // Do a blocking DNS resolution using the network-assigned nameservers.
-                final InetAddress[] ips = mCleartextDnsNetwork.getAllByName(
-                        mPrivateDnsProviderHostname);
+                final InetAddress[] ips = DnsUtils.getAllByName(mDependencies.getDnsResolver(),
+                        mCleartextDnsNetwork, mPrivateDnsProviderHostname, getDnsProbeTimeout());
                 mPrivateDnsConfig = new PrivateDnsConfig(mPrivateDnsProviderHostname, ips);
                 validationLog("Strict mode hostname resolved: " + mPrivateDnsConfig);
             } catch (UnknownHostException uhe) {
@@ -1489,39 +1492,8 @@ public class NetworkMonitor extends StateMachine {
     @VisibleForTesting
     protected InetAddress[] sendDnsProbeWithTimeout(String host, int timeoutMs)
                 throws UnknownHostException {
-        final CountDownLatch latch = new CountDownLatch(1);
-        final AtomicReference<List<InetAddress>> resultRef = new AtomicReference<>();
-        final DnsResolver.Callback<List<InetAddress>> callback =
-                    new DnsResolver.Callback<List<InetAddress>>() {
-            public void onAnswer(List<InetAddress> answer, int rcode) {
-                if (rcode == 0) {
-                    resultRef.set(answer);
-                }
-                latch.countDown();
-            }
-            public void onError(@NonNull DnsResolver.DnsException e) {
-                validationLog("DNS error resolving " + host + ": " + e.getMessage());
-                latch.countDown();
-            }
-        };
-
-        final int oldTag = TrafficStats.getAndSetThreadStatsTag(
-                TrafficStatsConstants.TAG_SYSTEM_PROBE);
-        mDependencies.getDnsResolver().query(mCleartextDnsNetwork, host, DnsResolver.FLAG_EMPTY,
-                r -> r.run() /* executor */, null /* cancellationSignal */, callback);
-        TrafficStats.setThreadStatsTag(oldTag);
-
-        try {
-            latch.await(timeoutMs, TimeUnit.MILLISECONDS);
-        } catch (InterruptedException e) {
-        }
-
-        List<InetAddress> result = resultRef.get();
-        if (result == null || result.size() == 0) {
-            throw new UnknownHostException(host);
-        }
-
-        return result.toArray(new InetAddress[0]);
+        return DnsUtils.getAllByName(mDependencies.getDnsResolver(), mCleartextDnsNetwork, host,
+                TYPE_ADDRCONFIG, FLAG_EMPTY, timeoutMs);
     }
 
     /** Do a DNS resolution of the given server. */