Library to Perform Link-Layer Packet Modification

Question

Is there a library out there that will allow me to perform link-layer packet modification for both incoming and outgoing packets?

Basically I want to do some transformations to a packet (for eg. changing IP payload) based on incoming MAC address, IP address, port, etc. I also want to be able to do the same thing for outgoing packets, i.e., modify packets before they leave the system.

Answer 1

I'm not sure if IPTables can do the kind of packet payload modification that I want to do. The article linked in the 1st answer allows modification only at network layer, not at link layer.

Solution: WinpkFilter

Answer 2

Windows or linux? for linux there's iptables which has extensive code. As for Windows, here's an article that might help you.

Hope this helps.