Linux 2.4 packet filter and the "nfmark" field.

[Zornitza Genova]

Hi all,
I am new to this board, working on implementing an TCP connection engine,
i.e. responsible for connection establishement and shutdown only. For this
purpose I need to implement my own stripped down version of TCP.
To do that, I need to fool TCP/IP on the Linux box, so that it does not
reply on packets destined to my stack.

One idea I have is to use the Linux 2.4 filter, and screen incoming
packets, i.e. set the nfmark filed and then, access them from my user
level code. Well, I can't find a place to show the function calls needed
to do that. I know how to mark the incoming packets (with the IPTABLES
command) but I don't know, how
to access their kernel headers from my code.

Any help will be much appreciated.

Zornitza

You can find the first steps to a Windows implementation of the connection
engine at:

http://www.csee.usf.edu/~christen/tools/toolpage.html

rawstuff.zip