public byte[] ToByteArray()
{
byte[] header = new byte[12];
int index = 0;
DnsUtil.GetBytes(header, ref index, Identification);
header[index++] = (byte)((QueryResponse ? 1 << 7 : 0)
| (((int)Opcode) << 3)
| (AuthoritativeAnswer ? 1 << 2 : 0)
| (Truncated ? 1 << 1 : 0)
| (RecursionDesired ? 1 : 0));
header[index++] = (byte)((RecursionAvailable ? 1 << 7 : 0)
| (AuthenticatedData ? 1 << 5 : 0)
| (CheckingDisabled ? 1 << 4 : 0)
| ((int)ReturnCode));
DnsUtil.GetBytes(header, ref index, TotalQuestions);
DnsUtil.GetBytes(header, ref index, TotalAnswers);
DnsUtil.GetBytes(header, ref index, TotalAuthorities);
DnsUtil.GetBytes(header, ref index, TotalAdditionalResources);
return(header.Concat(Questions.SelectMany(o => o.ToByteArray()))
.Concat(Answers.SelectMany(o => o.ToByteArray()))
.Concat(Authorities.SelectMany(o => o.ToByteArray()))
.Concat(AdditionalResources.SelectMany(o => o.ToByteArray()))
.ToArray());
}
public DnsPacket(byte[] buffer)
{
int index = 0;
Identification = DnsUtil.ToUInt16(buffer, ref index);
QueryResponse = (buffer[index] & (1 << 7)) != 0;
Opcode = (DnsOpcode)((buffer[index] >> 3) & 0b1111);
AuthoritativeAnswer = (buffer[index] & (1 << 2)) != 0;
Truncated = (buffer[index] & (1 << 1)) != 0;
RecursionDesired = (buffer[index++] & 1) != 0;
RecursionAvailable = (buffer[index] & (1 << 7)) != 0;
AuthenticatedData = (buffer[index] & (1 << 5)) != 0;
CheckingDisabled = (buffer[index] & (1 << 4)) != 0;
ReturnCode = (DnsReturnCode)(buffer[index++] & 0b1111);
TotalQuestions = DnsUtil.ToUInt16(buffer, ref index);
TotalAnswers = DnsUtil.ToUInt16(buffer, ref index);
TotalAuthorities = DnsUtil.ToUInt16(buffer, ref index);
TotalAdditionalResources = DnsUtil.ToUInt16(buffer, ref index);
for (int i = 0; i < TotalQuestions; ++i)
{
Questions[i] = new DnsQuestion(buffer, ref index);
}
for (int i = 0; i < TotalAnswers; ++i)
{
Answers[i] = new DnsResourceRecord(buffer, ref index);
}
for (int i = 0; i < TotalAuthorities; ++i)
{
Authorities[i] = new DnsResourceRecord(buffer, ref index);
}
for (int i = 0; i < TotalAdditionalResources; ++i)
{
AdditionalResources[i] = new DnsResourceRecord(buffer, ref index);
}
}
public DnsResourceRecord(byte[] buffer, ref int index)
{
Name = DnsUtil.DecodeQuestionName(buffer, ref index);
Type = (DnsRecordType)DnsUtil.ToUInt16(buffer, ref index);
Class = (DnsClass)DnsUtil.ToUInt16(buffer, ref index);
TimeToLive = DnsUtil.ToUInt32(buffer, ref index);
DataLength = DnsUtil.ToUInt16(buffer, ref index);
Array.Copy(buffer, index, Data, 0, DataLength);
index += DataLength;
}
public byte[] ToByteArray()
{
int index = Name.Length + 2;
byte[] data = new byte[index + 10 + DataLength];
DnsUtil.EncodeQuestionName(Name, data, 0);
DnsUtil.GetBytes(data, ref index, (ushort)Type);
DnsUtil.GetBytes(data, ref index, (ushort)Class);
DnsUtil.GetBytes(data, ref index, TimeToLive);
DnsUtil.GetBytes(data, ref index, DataLength);
Data.CopyTo(data, index);
return(data);
}
static IEnumerable <string> DecodeQuestionNameParts(byte[] buffer, ref int index)
{
List <string> parts = new List <string>();
while (buffer[index] != 0)
{
if ((buffer[index] & 0b11000000) == 0b11000000)
{
int ptr = DnsUtil.ToUInt16(buffer, ref index);
ptr ^= 0b1100000000000000;
parts.AddRange(DecodeQuestionNameParts(buffer, ref ptr));
return(parts);
}