e8efcd82a8
Motivation: We can just use Objects.requireNonNull(...) as a replacement for ObjectUtil.checkNotNull(....) Modifications: - Use Objects.requireNonNull(...) Result: Less code to maintain.
116 lines
3.9 KiB
Java
116 lines
3.9 KiB
Java
/*
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* Copyright 2015 The Netty Project
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*
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* The Netty Project licenses this file to you under the Apache License,
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* version 2.0 (the "License"); you may not use this file except in compliance
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* with the License. You may obtain a copy of the License at:
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
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* WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
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* License for the specific language governing permissions and limitations
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* under the License.
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*/
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package io.netty.handler.codec.dns;
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import io.netty.buffer.ByteBuf;
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import io.netty.channel.ChannelHandler;
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import io.netty.channel.ChannelHandlerContext;
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import io.netty.channel.socket.DatagramPacket;
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import io.netty.handler.codec.CorruptedFrameException;
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import io.netty.handler.codec.MessageToMessageDecoder;
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import io.netty.util.internal.UnstableApi;
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import java.util.List;
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import static java.util.Objects.requireNonNull;
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/**
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* Decodes a {@link DatagramPacket} into a {@link DatagramDnsQuery}.
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*/
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@UnstableApi
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@ChannelHandler.Sharable
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public class DatagramDnsQueryDecoder extends MessageToMessageDecoder<DatagramPacket> {
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private final DnsRecordDecoder recordDecoder;
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/**
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* Creates a new decoder with {@linkplain DnsRecordDecoder#DEFAULT the default record decoder}.
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*/
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public DatagramDnsQueryDecoder() {
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this(DnsRecordDecoder.DEFAULT);
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}
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/**
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* Creates a new decoder with the specified {@code recordDecoder}.
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*/
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public DatagramDnsQueryDecoder(DnsRecordDecoder recordDecoder) {
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this.recordDecoder = requireNonNull(recordDecoder, "recordDecoder");
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}
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@Override
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protected void decode(ChannelHandlerContext ctx, DatagramPacket packet, List<Object> out) throws Exception {
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final ByteBuf buf = packet.content();
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final DnsQuery query = newQuery(packet, buf);
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boolean success = false;
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try {
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final int questionCount = buf.readUnsignedShort();
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final int answerCount = buf.readUnsignedShort();
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final int authorityRecordCount = buf.readUnsignedShort();
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final int additionalRecordCount = buf.readUnsignedShort();
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decodeQuestions(query, buf, questionCount);
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decodeRecords(query, DnsSection.ANSWER, buf, answerCount);
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decodeRecords(query, DnsSection.AUTHORITY, buf, authorityRecordCount);
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decodeRecords(query, DnsSection.ADDITIONAL, buf, additionalRecordCount);
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out.add(query);
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success = true;
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} finally {
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if (!success) {
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query.release();
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}
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}
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}
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private static DnsQuery newQuery(DatagramPacket packet, ByteBuf buf) {
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final int id = buf.readUnsignedShort();
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final int flags = buf.readUnsignedShort();
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if (flags >> 15 == 1) {
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throw new CorruptedFrameException("not a query");
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}
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final DnsQuery query =
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new DatagramDnsQuery(
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packet.sender(),
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packet.recipient(),
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id,
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DnsOpCode.valueOf((byte) (flags >> 11 & 0xf)));
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query.setRecursionDesired((flags >> 8 & 1) == 1);
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query.setZ(flags >> 4 & 0x7);
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return query;
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}
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private void decodeQuestions(DnsQuery query, ByteBuf buf, int questionCount) throws Exception {
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for (int i = questionCount; i > 0; i--) {
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query.addRecord(DnsSection.QUESTION, recordDecoder.decodeQuestion(buf));
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}
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}
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private void decodeRecords(
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DnsQuery query, DnsSection section, ByteBuf buf, int count) throws Exception {
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for (int i = count; i > 0; i--) {
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final DnsRecord r = recordDecoder.decodeRecord(buf);
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if (r == null) {
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// Truncated response
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break;
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}
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query.addRecord(section, r);
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}
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}
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}
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