001 /* 002 * Licensed to the Apache Software Foundation (ASF) under one 003 * or more contributor license agreements. See the NOTICE file 004 * distributed with this work for additional information 005 * regarding copyright ownership. The ASF licenses this file 006 * to you under the Apache License, Version 2.0 (the 007 * "License"); you may not use this file except in compliance 008 * with the License. You may obtain a copy of the License at 009 * 010 * http://www.apache.org/licenses/LICENSE-2.0 011 * 012 * Unless required by applicable law or agreed to in writing, 013 * software distributed under the License is distributed on an 014 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY 015 * KIND, either express or implied. See the License for the 016 * specific language governing permissions and limitations 017 * under the License. 018 * 019 */ 020 021 package org.apache.directory.server.dns.protocol; 022 023 024 import org.apache.directory.server.dns.io.decoder.DnsMessageDecoder; 025 import org.apache.directory.server.i18n.I18n; 026 import org.apache.mina.core.buffer.IoBuffer; 027 import org.apache.mina.core.session.IoSession; 028 import org.apache.mina.filter.codec.CumulativeProtocolDecoder; 029 import org.apache.mina.filter.codec.ProtocolDecoderOutput; 030 031 032 /** 033 * A {@link CumulativeProtocolDecoder} which supports DNS operation over TCP, 034 * by reassembling split packets prior to decoding. 035 * 036 * @author <a href="mailto:dev@directory.apache.org">Apache Directory Project</a> 037 * @version $Rev: 545041 $, $Date: 2007-06-06 20:31:34 -0700 (Wed, 06 Jun 2007) $ 038 */ 039 public class DnsTcpDecoder extends CumulativeProtocolDecoder 040 { 041 private DnsMessageDecoder decoder = new DnsMessageDecoder(); 042 043 private int maxObjectSize = 16384; // 16KB 044 045 046 /** 047 * Returns the allowed maximum size of the object to be decoded. 048 * If the size of the object to be decoded exceeds this value, this 049 * decoder will throw a {@link BufferDataException}. The default 050 * value is <tt>16384</tt> (16KB). 051 * 052 * @return The max object size. 053 */ 054 public int getMaxObjectSize() 055 { 056 return maxObjectSize; 057 } 058 059 060 /** 061 * Sets the allowed maximum size of the object to be decoded. 062 * If the size of the object to be decoded exceeds this value, this 063 * decoder will throw a {@link BufferDataException}. The default 064 * value is <tt>16384</tt> (16KB). 065 * 066 * @param maxObjectSize 067 */ 068 public void setMaxObjectSize( int maxObjectSize ) 069 { 070 if ( maxObjectSize <= 0 ) 071 { 072 throw new IllegalArgumentException( I18n.err( I18n.ERR_634, maxObjectSize ) ); 073 } 074 075 this.maxObjectSize = maxObjectSize; 076 } 077 078 079 @Override 080 protected boolean doDecode( IoSession session, IoBuffer in, ProtocolDecoderOutput out ) throws Exception 081 { 082 if ( !in.prefixedDataAvailable( 2, maxObjectSize ) ) 083 { 084 return false; 085 } 086 087 in.getShort(); 088 089 out.write( decoder.decode( in ) ); 090 091 return true; 092 } 093 }