KeepAliveExtention

KeepAlive.cs

        public static void UseKeepAlive(this TcpClient client, ulong time = 2000, ulong interval = 500)
        {
            if (client == null)
                return;
            // "consts" to help understand calculations
            const int bytesperlong = 4; // 32 / 8
            const int bitsperbyte = 8;

            try
            {
                // resulting structure
                byte[] SIO_KEEPALIVE_VALS = new byte[3 * bytesperlong];

                // array to hold input values
                ulong[] input = new ulong[3];

                // put input arguments in input array
                if (time == 0 | interval == 0) // enable disable keep-alive
                    input[0] = (0UL); // off
                else
                    input[0] = (1UL); // on

                input[1] = (time); // time millis
                input[2] = (interval); // interval millis

                // pack input into byte struct
                for (int i = 0; i < input.Length; i++)
                {
                    SIO_KEEPALIVE_VALS[i * bytesperlong + 3] = (byte)(input[i] >> ((bytesperlong - 1) * bitsperbyte) & 0xff);
                    SIO_KEEPALIVE_VALS[i * bytesperlong + 2] = (byte)(input[i] >> ((bytesperlong - 2) * bitsperbyte) & 0xff);
                    SIO_KEEPALIVE_VALS[i * bytesperlong + 1] = (byte)(input[i] >> ((bytesperlong - 3) * bitsperbyte) & 0xff);
                    SIO_KEEPALIVE_VALS[i * bytesperlong + 0] = (byte)(input[i] >> ((bytesperlong - 4) * bitsperbyte) & 0xff);
                }
                // create bytestruct for result (bytes pending on server socket)
                byte[] result = BitConverter.GetBytes(0);
                // write SIO_VALS to Socket IOControl
                client.Client.IOControl(IOControlCode.KeepAliveValues, SIO_KEEPALIVE_VALS, result);
            }
            catch (Exception ex)
            {
                Log.HandleException(ex);
            }
        }