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 021package org.apache.directory.server.dns.protocol; 022 023 024import org.apache.directory.server.dns.io.encoder.DnsMessageEncoder; 025import org.apache.directory.server.dns.messages.DnsMessage; 026import org.apache.mina.core.buffer.IoBuffer; 027import org.apache.mina.core.session.IoSession; 028import org.apache.mina.filter.codec.ProtocolEncoderAdapter; 029import org.apache.mina.filter.codec.ProtocolEncoderOutput; 030 031 032/** 033 * A ProtocolEncoder for use in the MINA framework that uses the 034 * DnsMessageEncoder to encode DnsMessages. 035 * 036 * @author <a href="mailto:dev@directory.apache.org">Apache Directory Project</a> 037 */ 038public class DnsTcpEncoder extends ProtocolEncoderAdapter 039{ 040 private DnsMessageEncoder encoder = new DnsMessageEncoder(); 041 042 043 public void encode( IoSession session, Object message, ProtocolEncoderOutput out ) 044 { 045 IoBuffer buf = IoBuffer.allocate( 1024 ); 046 047 // make space for short length 048 buf.putShort( ( short ) 0 ); 049 050 encoder.encode( buf, ( DnsMessage ) message ); 051 052 // mark position 053 int end = buf.position(); 054 055 // length is the data minus 2 bytes for the pre-pended length 056 short recordLength = ( short ) ( end - 2 ); 057 058 // write the length 059 buf.rewind(); 060 buf.putShort( recordLength ); 061 062 // set the position back before flipping the buffer 063 buf.position( end ); 064 buf.flip(); 065 066 out.write( buf ); 067 } 068}