1 /*
2 * Licensed to the Apache Software Foundation (ASF) under one
3 * or more contributor license agreements. See the NOTICE file
4 * distributed with this work for additional information
5 * regarding copyright ownership. The ASF licenses this file
6 * to you under the Apache License, Version 2.0 (the
7 * "License"); you may not use this file except in compliance
8 * with the License. You may obtain a copy of the License at
9 *
10 * http://www.apache.org/licenses/LICENSE-2.0
11 *
12 * Unless required by applicable law or agreed to in writing,
13 * software distributed under the License is distributed on an
14 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
15 * KIND, either express or implied. See the License for the
16 * specific language governing permissions and limitations
17 * under the License.
18 *
19 */
20
21 package org.apache.directory.server.dns.protocol;
22
23
24 import org.apache.directory.server.dns.io.decoder.DnsMessageDecoder;
25 import org.apache.directory.server.i18n.I18n;
26 import org.apache.mina.core.buffer.IoBuffer;
27 import org.apache.mina.core.session.IoSession;
28 import org.apache.mina.filter.codec.CumulativeProtocolDecoder;
29 import org.apache.mina.filter.codec.ProtocolDecoderOutput;
30
31
32 /**
33 * A {@link CumulativeProtocolDecoder} which supports DNS operation over TCP,
34 * by reassembling split packets prior to decoding.
35 *
36 * @author <a href="mailto:dev@directory.apache.org">Apache Directory Project</a>
37 */
38 public class DnsTcpDecoder extends CumulativeProtocolDecoder
39 {
40 private DnsMessageDecoder/decoder/DnsMessageDecoder.html#DnsMessageDecoder">DnsMessageDecoder decoder = new DnsMessageDecoder();
41
42 private int maxObjectSize = 16384; // 16KB
43
44
45 /**
46 * Returns the allowed maximum size of the object to be decoded.
47 *
48 * @return The max object size.
49 */
50 public int getMaxObjectSize()
51 {
52 return maxObjectSize;
53 }
54
55
56 /**
57 * Sets the allowed maximum size of the object to be decoded.
58 * If the size of the object to be decoded exceeds this value, this
59 * decoder will throw a {@link IllegalArgumentException}. The default
60 * value is <tt>16384</tt> (16KB).
61 *
62 * @param maxObjectSize
63 */
64 public void setMaxObjectSize( int maxObjectSize )
65 {
66 if ( maxObjectSize <= 0 )
67 {
68 throw new IllegalArgumentException( I18n.err( I18n.ERR_634, maxObjectSize ) );
69 }
70
71 this.maxObjectSize = maxObjectSize;
72 }
73
74
75 @Override
76 protected boolean doDecode( IoSession session, IoBuffer in, ProtocolDecoderOutput out ) throws Exception
77 {
78 if ( !in.prefixedDataAvailable( 2, maxObjectSize ) )
79 {
80 return false;
81 }
82
83 in.getShort();
84
85 out.write( decoder.decode( in ) );
86
87 return true;
88 }
89 }