通過Socket.SetSocketOption()實現TCP/IP KeepAlive機制(C#)

Using TCP/IP KeepAlive in C# I have been trying to make NetSocket.SetSocketOption work for TCP/IP KeepAlive

I have tried the following code

  public virtual void SetKeepAlive(ulong keepalive_time, ulong keepalive_interval)<br /> {<br /> int bytes_per_long = 32 / 8;<br /> byte[] keep_alive = new byte[3 * bytes_per_long];<br /> ulong[] input_params = new ulong[3];<br /> int i1;<br /> int bits_per_byte = 8;</p><p> if (keepalive_time == 0 || keepalive_interval == 0)<br /> input_params[0] = 0;<br /> else<br /> input_params[0] = 1;<br /> input_params[1] = keepalive_time;<br /> input_params[2] = keepalive_interval;<br /> for (i1 = 0; i1 < input_params.Length; i1++)<br /> {<br /> keep_alive[i1 * bytes_per_long + 3] = (byte)(input_params[i1] >> ((bytes_per_long - 1) * bits_per_byte) & 0xff);<br /> keep_alive[i1 * bytes_per_long + 2] = (byte)(input_params[i1] >> ((bytes_per_long - 2) * bits_per_byte) & 0xff);<br /> keep_alive[i1 * bytes_per_long + 1] = (byte)(input_params[i1] >> ((bytes_per_long - 3) * bits_per_byte) & 0xff);<br /> keep_alive[i1 * bytes_per_long + 0] = (byte)(input_params[i1] >> ((bytes_per_long - 4) * bits_per_byte) & 0xff);<br /> }<br /> LogTrace.Trace(this, "Keep Alive Bits: {0}", ByteArrayFormater.HexDump(keep_alive));<br /> NetSocket.SetSocketOption(SocketOptionLevel.Socket, SocketOptionName.KeepAlive, keep_alive);<br /> } /* method AsyncSocket SetKeepAlive */

The result is not error, no exception and no keepalive in the expected time frame.
I am passing both times in mill-seconds. The Trace that I have shows 12 bytes in the form of
01 00 00 00 10 27 00 00 98 3a 00 00 when called as SetKeepAlive(10000,15000);

I am not really sure if I need to put the bytes in this order or not. If working directly with the Winsock API, the keepalive
option uses a structure of 3 ULONGS with a 1 in the first one, the time in the 2nd one and the retry time (interval in this code)
in the third one.

另外，通過Socket.IOControl()也可以實現這種機制：http://blog.csdn.net/kenkao/archive/2010/03/25/5415159.aspx