Per http://www.solacesystems.com/blog/kernel-bypass-revving-up-linux-networking:
[...]a network driver called OpenOnload that use “kernel bypass” tec
Do you perhaps want to send and recieve raw IP packets?
Basically you will need to fill in headers and data in a ip-packet. There are some examples here on how to send raw ethernet packets: :http://austinmarton.wordpress.com/2011/09/14/sending-raw-ethernet-packets-from-a-specific-interface-in-c-on-linux/
To handle TCP/IP on your own, i think that you might need to disable the TCP driver in a custom kernel, and then write your own user space server that reads raw ip.
It's probably not that efficient though...