/*
* Copyright 2004-2006 Luke Quinane and Daniel Frampton
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*
*/
using System;
using NDns.Message.Records;
namespace NDns.Message{
/// <summary>
/// A answer section entry in a DNS message.
/// </summary>
public class AnswerSection
{
#region Attributes
/// <summary>
/// The string name in this answer.
/// </summary>
protected string answerName;
/// <summary>
/// The type of record.
/// </summary>
protected QType answerType;
/// <summary>
/// The query class.
/// </summary>
protected QClass answerClass = QClass.IN;
/// <summary>
/// The time to live for the answer.
/// </summary>
protected uint answerTTL;
/// <summary>
/// The record data associated with this record.
/// </summary>
protected Record answerRecord;
#endregion
#region Constructors
/// <summary>
/// Creates a answer section from the given byte data.
/// </summary>
/// <param name="data">The data to create the answer section from.</param>
/// <param name="start">The position to start reading the byte array from.</param>
/// <param name="length">The number of bytes read from the byte array.</param>
/// <param name="coder">The coder to use when parsing the data.</param>
public AnswerSection(byte[] data, ushort start, out ushort length, DomainCoder coder)
{
// get the answer name
ushort position;
this.answerName = coder.DecodeDomain(data, start, out position);
position += start;
// get the answer type
ushort type = (ushort) (data[position++] << 8);
type |= (ushort) data[position++];
this.answerType = (QType)type;
// ignore the class
position += 2;
this.answerClass = QClass.IN;
// get the TTL
this.answerTTL = (uint) data[position++] << 24;
this.answerTTL |= (uint) data[position++] << 16;
this.answerTTL |= (uint) data[position++] << 8;
this.answerTTL |= (uint) data[position++];
// get the record length
ushort recordLength = (ushort) (data[position++] << 8);
recordLength |= (ushort) data[position++];
// process the record data
ushort dataLength;
switch (this.answerType)
{
case QType.MX:
this.answerRecord = new MXRecord(data, position, out dataLength, coder);
this.answerRecord.TTL = this.answerTTL;
position += dataLength;
break;
case QType.A:
this.answerRecord = new ARecord(data, position, out dataLength, coder);
this.answerRecord.TTL = this.answerTTL;
position += dataLength;
break;
case QType.CNAME:
this.answerRecord = new CNameRecord(data, position, out dataLength, coder);
this.answerRecord.TTL = this.answerTTL;
position += dataLength;
break;
case QType.NS:
this.answerRecord = new NSRecord(data, position, out dataLength, coder);
this.answerRecord.TTL = this.answerTTL;
position += dataLength;
break;
case QType.PTR:
this.answerRecord = new PTRRecord(data, position, out dataLength, coder);
this.answerRecord.TTL = this.answerTTL;
position += dataLength;
break;
default:
throw new FormatException("Invalid answer type: " + this.answerType);
}
length = (ushort) (position - start);
}
#endregion
/// <summary>
/// The answer record associated with this answer entry.
/// </summary>
public Record Record
{
get
{
return this.answerRecord;
}
}
}
}
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