private void ConstructRequestData(DnsRequestMessage request, IDnsDatagramWriter writer)
{
DnsQuestion question = request.Question;
/*
* 1 1 1 1 1 1
* 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5
+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
| ID |
+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
|QR| Opcode |AA|TC|RD|RA| Z | RCODE |
+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
| QDCOUNT |
+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
| ANCOUNT |
+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
| NSCOUNT |
+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
| ARCOUNT |
+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
* */
// 4 more bytes for the type and class
writer.WriteInt16NetworkOrder((short)request.Header.Identifier);
writer.WriteUInt16NetworkOrder(request.Header.RawFlags);
writer.WriteInt16NetworkOrder(1); // we support single question only... (as most DNS servers anyways).
writer.WriteInt16NetworkOrder(0);
writer.WriteInt16NetworkOrder(0);
writer.WriteInt16NetworkOrder(1); // one additional for the Opt record.
writer.WriteHostName(question.QueryName.Value);
writer.WriteUInt16NetworkOrder((ushort)question.QuestionType);
writer.WriteUInt16NetworkOrder((ushort)question.QuestionClass);
/*
+------------+--------------+------------------------------+
| Field Name | Field Type | Description |
+------------+--------------+------------------------------+
| NAME | domain name | MUST be 0 (root domain) |
| TYPE | u_int16_t | OPT (41) |
| CLASS | u_int16_t | requester's UDP payload size |
| TTL | u_int32_t | extended RCODE and flags |
| RDLEN | u_int16_t | length of all RDATA |
| RDATA | octet stream | {attribute,value} pairs |
+------------+--------------+------------------------------+
* */
var opt = new OptRecord();
writer.WriteHostName("");
writer.WriteUInt16NetworkOrder((ushort)opt.RecordType);
writer.WriteUInt16NetworkOrder((ushort)opt.RecordClass);
writer.WriteUInt32NetworkOrder((ushort)opt.InitialTimeToLive);
writer.WriteUInt16NetworkOrder(0);
}
public void WriteInt16NetworkOrder_should_write_value_in_the_data_array()
{
// Arrange.
const short value = 45;
// Act.
writer.WriteInt16NetworkOrder(value);
// not so 'Act'
byte[] data = SubArray(writer.Data.Array, 0, writer.Data.Count);
ArraySegment <byte> arrData = new ArraySegment <byte>(data);
ushort result = Read(arrData); // (ushort)(ReadByte(arrData, 0) << 8 | ReadByte(arrData, 1));
// Assert.
Assert.AreEqual(value, result);
}
