76 lines
2.6 KiB
Java
76 lines
2.6 KiB
Java
/*
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* Copyright 2019 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 static io.netty.util.internal.ObjectUtil.checkNotNull;
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final class DnsQueryEncoder {
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private final DnsRecordEncoder recordEncoder;
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/**
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* Creates a new encoder with the specified {@code recordEncoder}.
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*/
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DnsQueryEncoder(DnsRecordEncoder recordEncoder) {
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this.recordEncoder = checkNotNull(recordEncoder, "recordEncoder");
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}
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/**
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* Encodes the given {@link DnsQuery} into a {@link ByteBuf}.
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*/
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void encode(DnsQuery query, ByteBuf out) throws Exception {
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encodeHeader(query, out);
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encodeQuestions(query, out);
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encodeRecords(query, DnsSection.ADDITIONAL, out);
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}
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/**
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* Encodes the header that is always 12 bytes long.
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*
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* @param query the query header being encoded
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* @param buf the buffer the encoded data should be written to
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*/
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private static void encodeHeader(DnsQuery query, ByteBuf buf) {
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buf.writeShort(query.id());
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int flags = 0;
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flags |= (query.opCode().byteValue() & 0xFF) << 14;
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if (query.isRecursionDesired()) {
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flags |= 1 << 8;
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}
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buf.writeShort(flags);
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buf.writeShort(query.count(DnsSection.QUESTION));
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buf.writeShort(0); // answerCount
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buf.writeShort(0); // authorityResourceCount
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buf.writeShort(query.count(DnsSection.ADDITIONAL));
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}
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private void encodeQuestions(DnsQuery query, ByteBuf buf) throws Exception {
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final int count = query.count(DnsSection.QUESTION);
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for (int i = 0; i < count; i++) {
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recordEncoder.encodeQuestion((DnsQuestion) query.recordAt(DnsSection.QUESTION, i), buf);
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}
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}
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private void encodeRecords(DnsQuery query, DnsSection section, ByteBuf buf) throws Exception {
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final int count = query.count(section);
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for (int i = 0; i < count; i++) {
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recordEncoder.encodeRecord(query.recordAt(section, i), buf);
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}
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}
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}
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