byte[] BuildRequest(Message request)
{
// Always have a query ID.
if (request.Id == 0)
{
request.Id = this.NextQueryId();
}
// Add an OPT if not already present.
var opt = request.AdditionalRecords.OfType <OPTRecord>().FirstOrDefault();
if (opt == null)
{
opt = new OPTRecord();
request.AdditionalRecords.Add(opt);
}
// Keep the connection alive.
if (!opt.Options.Any(o => o.Type == EdnsOptionType.Keepalive))
{
var keepalive = new EdnsKeepaliveOption
{
Timeout = TimeSpan.FromMinutes(2)
};
opt.Options.Add(keepalive);
}
;
// Always use padding. Must be the last transform.
if (!opt.Options.Any(o => o.Type == EdnsOptionType.Padding))
{
var paddingOption = new EdnsPaddingOption();
opt.Options.Add(paddingOption);
var need = BlockLength - ((request.Length() + 2) % BlockLength);
if (need > 0)
{
paddingOption.Padding = new byte[need];
rng.NextBytes(paddingOption.Padding);
}
}
;
using (var tcpRequest = new MemoryStream())
{
tcpRequest.WriteByte(0); // two byte length prefix
tcpRequest.WriteByte(0);
request.Write(tcpRequest); // udpRequest
var length = (ushort)(tcpRequest.Length - 2);
tcpRequest.Position = 0;
tcpRequest.WriteByte((byte)(length >> 8));
tcpRequest.WriteByte((byte)(length));
return(tcpRequest.ToArray());
}
}
public void Roundtrip_Empty()
{
var opt1 = new OPTRecord();
var expected = new EdnsKeepaliveOption();
Assert.AreEqual(EdnsOptionType.Keepalive, expected.Type);
Assert.AreEqual(false, expected.Timeout.HasValue);
opt1.Options.Add(expected);
var opt2 = (OPTRecord) new ResourceRecord().Read(opt1.ToByteArray());
var actual = (EdnsKeepaliveOption)opt2.Options[0];
Assert.AreEqual(expected.Type, actual.Type);
Assert.AreEqual(expected.Timeout.HasValue, actual.Timeout.HasValue);
}
public void Roundtrip()
{
var opt1 = new OPTRecord();
var expected = new EdnsKeepaliveOption
{
Timeout = TimeSpan.FromSeconds(3)
};
Assert.AreEqual(EdnsOptionType.Keepalive, expected.Type);
opt1.Options.Add(expected);
var opt2 = (OPTRecord) new ResourceRecord().Read(opt1.ToByteArray());
var actual = (EdnsKeepaliveOption)opt2.Options[0];
Assert.AreEqual(expected.Type, actual.Type);
Assert.AreEqual(expected.Timeout.Value, actual.Timeout.Value);
}