[ns] Urgent, how could I access the value of congestion window of a TCP flow in C code not tcl??

[Aldabbagh Ghadah]

Dear all,
I am designing an Active Queue Management algorithm in ns2.
Basically, a packet enters the system and my algorithm is supposed to decide whether to place the packet in the queue or drop it according to some criteria. I need to know the congestion window value of a TCP flow, how could I access it.
How could I define a TCP agent in my C code not my tcl code??? Then how could I access the congestion window value of that flow, knowing that in tcp.h, the congestion window is protected.
I need your help urgently, please.
Awaiting a response,
Ghadah