diff --git a/example/pom.xml b/example/pom.xml index 93e5098095..bf318e0cd2 100644 --- a/example/pom.xml +++ b/example/pom.xml @@ -108,6 +108,11 @@ netty-codec-haproxy ${project.version} + + ${project.groupId} + netty-codec-dns + ${project.version} + com.google.protobuf diff --git a/example/src/main/java/io/netty/example/dns/udp/DnsClient.java b/example/src/main/java/io/netty/example/dns/udp/DnsClient.java new file mode 100644 index 0000000000..7a7381b8b6 --- /dev/null +++ b/example/src/main/java/io/netty/example/dns/udp/DnsClient.java @@ -0,0 +1,107 @@ +/* + * Copyright 2020 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 + * License for the specific language governing permissions and limitations + * under the License. + */ +package io.netty.example.dns.udp; + +import java.net.InetSocketAddress; +import java.util.concurrent.TimeUnit; + +import io.netty.bootstrap.Bootstrap; +import io.netty.buffer.ByteBufUtil; +import io.netty.channel.Channel; +import io.netty.channel.ChannelHandlerContext; +import io.netty.channel.ChannelInitializer; +import io.netty.channel.ChannelPipeline; +import io.netty.channel.EventLoopGroup; +import io.netty.channel.SimpleChannelInboundHandler; +import io.netty.channel.nio.NioEventLoopGroup; +import io.netty.channel.socket.DatagramChannel; +import io.netty.channel.socket.nio.NioDatagramChannel; +import io.netty.handler.codec.dns.DatagramDnsQuery; +import io.netty.handler.codec.dns.DatagramDnsQueryEncoder; +import io.netty.handler.codec.dns.DatagramDnsResponse; +import io.netty.handler.codec.dns.DatagramDnsResponseDecoder; +import io.netty.handler.codec.dns.DefaultDnsQuestion; +import io.netty.handler.codec.dns.DnsQuery; +import io.netty.handler.codec.dns.DnsQuestion; +import io.netty.handler.codec.dns.DnsRawRecord; +import io.netty.handler.codec.dns.DnsRecord; +import io.netty.handler.codec.dns.DnsRecordType; +import io.netty.handler.codec.dns.DnsSection; +import io.netty.util.NetUtil; + +public final class DnsClient { + + private static final String QUERY_DOMAIN = "www.example.com"; + private static final int DNS_SERVER_PORT = 53; + private static final String DNS_SERVER_HOST = "8.8.8.8"; + + private DnsClient() { } + + private static void handleQueryResp(DatagramDnsResponse msg) { + if (msg.count(DnsSection.QUESTION) > 0) { + DnsQuestion question = msg.recordAt(DnsSection.QUESTION, 0); + System.out.printf("name: %s%n", question.name()); + } + for (int i = 0, count = msg.count(DnsSection.ANSWER); i < count; i++) { + DnsRecord record = msg.recordAt(DnsSection.ANSWER, i); + if (record.type() == DnsRecordType.A) { + //just print the IP after query + DnsRawRecord raw = (DnsRawRecord) record; + System.out.println(NetUtil.bytesToIpAddress(ByteBufUtil.getBytes(raw.content()))); + } + } + } + + public static void main(String[] args) throws Exception { + InetSocketAddress addr = new InetSocketAddress(DNS_SERVER_HOST, DNS_SERVER_PORT); + EventLoopGroup group = new NioEventLoopGroup(); + try { + Bootstrap b = new Bootstrap(); + b.group(group) + .channel(NioDatagramChannel.class) + .handler(new ChannelInitializer() { + @Override + protected void initChannel(DatagramChannel ch) throws Exception { + ChannelPipeline p = ch.pipeline(); + p.addLast(new DatagramDnsQueryEncoder()) + .addLast(new DatagramDnsResponseDecoder()) + .addLast(new SimpleChannelInboundHandler() { + @Override + protected void channelRead0(ChannelHandlerContext ctx, DatagramDnsResponse msg) { + try { + handleQueryResp(msg); + } finally { + ctx.close(); + } + } + }); + } + }); + final Channel ch = b.bind(0).sync().channel(); + DnsQuery query = new DatagramDnsQuery(null, addr, 1).setRecord( + DnsSection.QUESTION, + new DefaultDnsQuestion(QUERY_DOMAIN, DnsRecordType.A)); + ch.writeAndFlush(query).sync(); + boolean succ = ch.closeFuture().await(10, TimeUnit.SECONDS); + if (!succ) { + System.err.println("dns query timeout!"); + ch.close().sync(); + } + } finally { + group.shutdownGracefully(); + } + } +}