modification of tcp flags using netfilter hooks??

Hello,
I have wriiten a module using netfilter hooks for catching
packets n then modifying it.. First using NF_IP_PRE_ROUTING hook i am
trying to modify the incoming tcp packet.. I want to change the tcp
flags for the incoming packet..I have handled the checksum issues for
that.. What othere issues i need to handle???
Thanks...

Regards
Sunny

 

It depends on which flags you're working.
If it's on URG, you've got to see the urgent pointer in the header.

If you touch SYN, FIN, ACK or RST, you should'nt count on a normal
TCP/IP
connection.

 

Hi Sunny,
I am trying to do the same thing. Did you eventually found a solution?

Thanks,
Arrigo

 

You're replying to a posting which is almost seven years old. "Sunny"
is probably no longer reading this group.

What are you trying to accomplish? Modifying TCP flags (the
SYN/ACK/RST/PSH/etc bits) before they reach ip_rcv() seems rather
pointless, so I'm thinking the solution to your problem probably lies
elsewhere?

/Jorgen