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using System;
namespace Heijden.DNS
{
#region RFC info
/*
3.2. RR definitions
3.2.1. Format
All RRs have the same top level format shown below:
1 1 1 1 1 1
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5
+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
| |
/ /
/ NAME /
| |
+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
| TYPE |
+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
| CLASS |
+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
| TTL |
| |
+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
| RDLENGTH |
+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--|
/ RDATA /
/ /
+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
where:
NAME an owner name, i.e., the name of the node to which this
resource record pertains.
TYPE two octets containing one of the RR TYPE codes.
CLASS two octets containing one of the RR CLASS codes.
TTL a 32 bit signed integer that specifies the time interval
that the resource record may be cached before the source
of the information should again be consulted. Zero
values are interpreted to mean that the RR can only be
used for the transaction in progress, and should not be
cached. For example, SOA records are always distributed
with a zero TTL to prohibit caching. Zero values can
also be used for extremely volatile data.
RDLENGTH an unsigned 16 bit integer that specifies the length in
octets of the RDATA field.
RDATA a variable length string of octets that describes the
resource. The format of this information varies
according to the TYPE and CLASS of the resource record.
*/
#endregion
/// <summary>
/// Resource Record (rfc1034 3.6.)
/// </summary>
public class RR
{
/// <summary>
/// The name of the node to which this resource record pertains
/// </summary>
public string NAME;
/// <summary>
/// Specifies type of resource record
/// </summary>
public Type Type;
/// <summary>
/// Specifies type class of resource record, mostly IN but can be CS, CH or HS
/// </summary>
public Class Class;
/// <summary>
/// Time to live, the time interval that the resource record may be cached
/// </summary>
public uint TTL
{
get
{
return (uint)Math.Max(0, m_TTL - TimeLived);
}
set
{
m_TTL = value;
}
}
private uint m_TTL;
/// <summary>
///
/// </summary>
public ushort RDLENGTH;
/// <summary>
/// One of the Record* classes
/// </summary>
public Record RECORD;
public int TimeLived;
public RR(RecordReader rr)
{
TimeLived = 0;
NAME = rr.ReadDomainName();
Type = (Type)rr.ReadUInt16();
Class = (Class)rr.ReadUInt16();
TTL = rr.ReadUInt32();
RDLENGTH = rr.ReadUInt16();
RECORD = rr.ReadRecord(Type, RDLENGTH);
RECORD.RR = this;
}
public override string ToString()
{
return string.Format("{0,-32} {1}\t{2}\t{3}\t{4}",
NAME,
TTL,
Class,
Type,
RECORD);
}
}
public class AnswerRR : RR
{
public AnswerRR(RecordReader br)
: base(br)
{
}
}
public class AuthorityRR : RR
{
public AuthorityRR(RecordReader br)
: base(br)
{
}
}
public class AdditionalRR : RR
{
public AdditionalRR(RecordReader br)
: base(br)
{
}
}
}
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Vasudevan Deepak Kumar is from Chennai, India who has been in the programming career since 1994, when he was 15 years old. He has his Bachelors of Engineering (in Computer Science and Engineering) from
Vellore Engineering College. He also has a MBA in Systems from
Alagappa University, Karaikudi, India.
He started his programming career with GWBasic and then in his college was involved in developing programs in Fortran, Cobol, C++. He has been developing in Microsoft technologies like ASP, SQLServer 2000.
His current focus is ASP.NET, C#, VB.NET, PHP, SQL Server and MySQL. In his past-time, he listens to polite Carnatic Music. But the big question is that with his current Todolist backlog, does he get some past time?