Hi there I need your help on doing the following.


I'm writing a program and I need to use the linux network stack so as to do the following.


When a packet arrives to the linux router and its destination is for pc A to forward it to another computer B which is locate outside the network.
Someone may tell me that this can be done with classical routing methods but what I want is to dynamically change the routes under certain circumstances.
So I want to call function of the linux network stack through my program.
Are there any specific system calls?Where can I find more info

thanx

Have a look at NAT with iptables. Mappings can be altered dynamically.

If you insist on writing your own code, you will need to write a kernel module (I think, but you should double-check, maybe by posting a more specific question in the programming forum).

Writing a kernel module can be very long, and I'm almost sure iptables can do the job you need.

http://www.tldp.org/HOWTO/IP-Masquerade-HOWTO/
http://www.netfilter.org/documentation/index.html