/// <summary>
/// Does STUN transaction. Returns transaction response or null if transaction failed.
/// </summary>
/// <param name="request">STUN message.</param>
/// <param name="socket">Socket to use for send/receive.</param>
/// <param name="remoteEndPoint">Remote end point.</param>
/// <param name="timeout">Timeout in milliseconds.</param>
/// <returns>Returns transaction response or null if transaction failed.</returns>
private static StunMessage DoTransaction(StunMessage request, Socket socket, IPEndPoint remoteEndPoint, int timeout)
{
var requestBytes = request.ToByteData();
var startTime = DateTime.Now;
// Retransmit with 500 ms.
while (startTime.AddMilliseconds(timeout) > DateTime.Now)
{
try
{
socket.SendTo(requestBytes, remoteEndPoint);
// We got response.
if (socket.Poll(500 * 1000, SelectMode.SelectRead))
{
var receiveBuffer = new byte[512];
socket.Receive(receiveBuffer);
// Parse message
var response = new StunMessage();
response.Parse(receiveBuffer);
// Check that transaction ID matches or not response what we want.
if (NetUtils.CompareArray(request.TransactionId, response.TransactionId))
{
return(response);
}
}
}
catch
{
// ignored
}
}
return(null);
}