68 lines
2.3 KiB
Java
68 lines
2.3 KiB
Java
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/*
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* Copyright 2018 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.resolver.dns;
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import java.net.IDN;
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import java.net.InetAddress;
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import java.net.UnknownHostException;
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import io.netty.buffer.ByteBuf;
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import io.netty.buffer.ByteBufHolder;
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import io.netty.handler.codec.dns.DnsRawRecord;
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import io.netty.handler.codec.dns.DnsRecord;
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/**
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* Decodes an {@link InetAddress} from an A or AAAA {@link DnsRawRecord}.
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*/
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final class DnsAddressDecoder {
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private static final int INADDRSZ4 = 4;
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private static final int INADDRSZ6 = 16;
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/**
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* Decodes an {@link InetAddress} from an A or AAAA {@link DnsRawRecord}.
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*
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* @param record the {@link DnsRecord}, most likely a {@link DnsRawRecord}
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* @param name the host name of the decoded address
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* @param decodeIdn whether to convert {@code name} to a unicode host name
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*
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* @return the {@link InetAddress}, or {@code null} if {@code record} is not a {@link DnsRawRecord} or
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* its content is malformed
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*/
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static InetAddress decodeAddress(DnsRecord record, String name, boolean decodeIdn) {
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if (!(record instanceof DnsRawRecord)) {
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return null;
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}
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final ByteBuf content = ((ByteBufHolder) record).content();
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final int contentLen = content.readableBytes();
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if (contentLen != INADDRSZ4 && contentLen != INADDRSZ6) {
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return null;
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}
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final byte[] addrBytes = new byte[contentLen];
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content.getBytes(content.readerIndex(), addrBytes);
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try {
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return InetAddress.getByAddress(decodeIdn ? IDN.toUnicode(name) : name, addrBytes);
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} catch (UnknownHostException e) {
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// Should never reach here.
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throw new Error(e);
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}
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}
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private DnsAddressDecoder() { }
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}
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