| /* |
| * 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]); |
| } |
| } |