TCP window scaling on Windows

Question

I have to implement in C/C++ a software for FTP upload in Windows XP and Windows 7 with TCP window scaling disabled.
I know that in Windows 7 is possible to disable it globally with the command

'netsh interface tcp set global autotuning=disabled' 

or in XP with the "Tcp1323Opts" registry parameter.
But these solutions works globally, and I need to change the behaviour only of my program.
I know that it's possible to do it because our customer has shown a program that executes the FTP upload disabling the TCP windows scaling (verified with wireshark), but I don't have the source code of that program.

Please anyone could help me? Thanks

Answer 1

See WSAIoctl with SIO_SET_COMPATIBILITY_MODE in MSDN; link here: http://msdn.microsoft.com/en-us/library/windows/desktop/cc136103(v=vs.85).aspx

This lets you set the WsaBehaviorAutoTuning value which can be used to turn off auto tuning on the socket in question.