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 WriteHostName_should_write_query_name_in_the_data_array_using_utf8_encoding()
{
// Arrange.
const string queryNameRoot = "www.microsoft.com.";
// Act.
writer.WriteHostName(queryNameRoot);
// Assert.
Assert.NotNull(writer.Data);
string result = Encoding.UTF8.GetString(writer.Data.Array, 1, writer.Data.Count);
Assert.AreEqual("www\tmicrosoft\u0003com\0\0", result);
}