/// <summary>
/// Executes the UDP request.
/// </summary>
/// <param name="uri">The URI.</param>
/// <param name="message">The message.</param>
/// <returns>
/// The tracker response message.
/// </returns>
private TrackerMessage ExecuteUdpRequest(Uri uri, TrackerMessage message)
{
uri.CannotBeNull();
message.CannotBeNull();
byte[] data = null;
IAsyncResult asyncResult;
IPEndPoint any = new IPEndPoint(IPAddress.Any, this.ListeningPort);
try
{
using (UdpClient udp = new UdpClient())
{
udp.Client.SendTimeout = (int)TimeSpan.FromSeconds(5).TotalMilliseconds;
udp.Client.ReceiveTimeout = (int)TimeSpan.FromSeconds(15).TotalMilliseconds;
if (this.TrackerUri.Port > 0)
{
udp.Send(message.Encode(), message.Length, this.TrackerUri.Host, this.TrackerUri.Port);
}
else
{
return(null);
}
asyncResult = udp.BeginReceive(null, null);
if (asyncResult.AsyncWaitHandle.WaitOne(TimeSpan.FromSeconds(5)))
{
data = udp.EndReceive(asyncResult, ref any);
}
else
{
// timeout
}
}
}
catch (SocketException ex)
{
Debug.WriteLine($"could not send message to UDP tracker {this.TrackerUri} for torrent {this.TorrentInfoHash}: {ex.Message}");
return(null);
}
if (TrackerMessage.TryDecode(data, 0, MessageType.Response, out message))
{
if (message is ErrorMessage)
{
Debug.WriteLine($"error message received from UDP tracker {this.TrackerUri}: \"{message.As<ErrorMessage>().ErrorText}\"");
}
return(message);
}
else
{
return(null);
}
}
