DnsMessage.cs

using System;
using System.Collections.Generic;
using System.IO;
using Waher.Networking.DNS.Enumerations;
using Waher.Networking.DNS.ResourceRecords;
 
namespace Waher.Networking.DNS.Communication
{
    public class DnsMessage
    {
        private readonly byte[] binary;
        private readonly ushort id;
        private readonly bool response;
        private readonly OpCode opCode;
        private readonly bool authoritativeAnswer;
        private readonly bool truncation;
        private readonly bool recursionDesired;
        private readonly bool recursionAvailable;
        private readonly RCode rCode;
        private readonly Question[] questions;
        private readonly ResourceRecord[] answer;
        private readonly ResourceRecord[] authority;
        private readonly ResourceRecord[] additional;
 
        public DnsMessage(byte[] Data)
        {
            this.binary = Data;
 
            using (MemoryStream ms = new MemoryStream(Data))
            {
                this.id = DnsClient.ReadUInt16(ms);
 
                byte b = (byte)ms.ReadByte();
                this.response = (b & 0x80) != 0;
                this.opCode = (OpCode)((b >> 3) & 15);
                this.authoritativeAnswer = (b & 4) != 0;
                this.truncation = (b & 2) != 0;
                this.recursionDesired = (b & 1) != 0;
 
                b = (byte)ms.ReadByte();
                this.recursionAvailable = (b & 128) != 0;
                this.rCode = (RCode)(b & 31);
 
                ushort QDCOUNT = DnsClient.ReadUInt16(ms);
                ushort ANCOUNT = DnsClient.ReadUInt16(ms);
                ushort NSCOUNT = DnsClient.ReadUInt16(ms);
                ushort ARCOUNT = DnsClient.ReadUInt16(ms);
 
                this.questions = new Question[QDCOUNT];
                ushort i;
 
                for (i = 0; i < QDCOUNT; i++)
                {
                    string QNAME = DnsClient.ReadName(ms);
                    QTYPE QTYPE = (QTYPE)DnsClient.ReadUInt16(ms);
                    QCLASS QCLASS = (QCLASS)DnsClient.ReadUInt16(ms);
 
                    this.questions[i] = new Question(QNAME, QTYPE, QCLASS);
                }
 
                this.answer = DnsClient.ReadResourceRecords(ms, ANCOUNT);
                this.authority = DnsClient.ReadResourceRecords(ms, NSCOUNT);
                this.additional = DnsClient.ReadResourceRecords(ms, ARCOUNT);
            }
        }
 
        public byte[] Binary => this.binary;
 
        public ushort ID => this.id;
 
        public bool Response => this.response;
 
        public OpCode OpCode => this.opCode;
 
        public bool AuthoritativeAnswer => this.authoritativeAnswer;
 
        public bool Truncation => this.truncation;
 
        public bool RecursionDesired => this.recursionDesired;
 
        public bool RecursionAvailable => this.recursionAvailable;
 
        public RCode RCode => this.rCode;
 
        public Question[] Questions => this.questions;
 
        public ResourceRecord[] Answer => this.answer;
 
        public ResourceRecord[] Authority => this.authority;
 
        public ResourceRecord[] Additional => this.additional;
 
    }
}