netty5/resolver-dns/src/test/java/io/netty/resolver/dns/DnsNameResolverClientSubnetTest.java
Scott Mitchell e074df2ae6 DNS Resolve ambiguity in which DNS servers are used during resolution
Motivation:
Recently DnsServerAddressStreamProvider was introduced to allow control for each query as to which DNS server should be used for resolution to respect the local host's default DNS server configuration. However resolver-dns also accepts a stream of DNS servers to use by default, but this stream is not host name aware. This creates an ambiguity as to which method is used to determine the DNS server to user during resolution, and in which order. We can remove this ambiguity and provide a more general API by just supporting DnsServerAddressStreamProvider.

Modifications:
- Remove the fixed DnsServerAddresses and instead only accept a DnsServerAddressStreamProvider.
- Add utility methods to help use DnsServerAddressStreamProvider for a single entry, a list of entries, and get the default for the current machine.

Result:
Fixes https://github.com/netty/netty/issues/6573.
2017-03-31 15:29:49 -07:00

69 lines
2.7 KiB
Java

/*
* Copyright 2016 The Netty Project
*
* The Netty Project licenses this file to you 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
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package io.netty.resolver.dns;
import io.netty.channel.EventLoopGroup;
import io.netty.channel.nio.NioEventLoopGroup;
import io.netty.channel.socket.nio.NioDatagramChannel;
import io.netty.handler.codec.dns.DefaultDnsOptEcsRecord;
import io.netty.handler.codec.dns.DnsRecord;
import io.netty.util.internal.SocketUtils;
import io.netty.util.concurrent.Future;
import org.junit.Ignore;
import org.junit.Test;
import java.net.InetAddress;
import java.util.Collections;
import java.util.List;
import java.util.concurrent.TimeUnit;
public class DnsNameResolverClientSubnetTest {
// See https://www.gsic.uva.es/~jnisigl/dig-edns-client-subnet.html
// Ignore as this needs to query real DNS servers.
@Ignore
@Test
public void testSubnetQuery() throws Exception {
EventLoopGroup group = new NioEventLoopGroup(1);
DnsNameResolver resolver = newResolver(group).build();
try {
// Same as:
// # /.bind-9.9.3-edns/bin/dig @ns1.google.com www.google.es +client=157.88.0.0/24
Future<List<InetAddress>> future = resolver.resolveAll("www.google.es",
Collections.<DnsRecord>singleton(
// Suggest max payload size of 1024
// 157.88.0.0 / 24
new DefaultDnsOptEcsRecord(1024, 24,
SocketUtils.addressByName("157.88.0.0").getAddress())));
for (InetAddress address: future.syncUninterruptibly().getNow()) {
System.err.println(address);
}
} finally {
resolver.close();
group.shutdownGracefully(0, 0, TimeUnit.SECONDS);
}
}
private static DnsNameResolverBuilder newResolver(EventLoopGroup group) {
return new DnsNameResolverBuilder(group.next())
.channelType(NioDatagramChannel.class)
.nameServerProvider(
new SingletonDnsServerAddressStreamProvider(SocketUtils.socketAddress("8.8.8.8", 53)))
.maxQueriesPerResolve(1)
.optResourceEnabled(false);
}
}