Also I am a techie and wanna know how to join the developer network of Ubuntu?
The implementation of ARP in Linux is part of the kernel.
The kernel in 10.10 is kernel version 2.6.35 ; you can get this from git repositories.
As for joining the Ubuntu developers ; hang around on Ubuntu channels on the FreeNode IRC network, sign up for a Launchpad account, find a project which you think needs improving, and contribute. You don't have to do great things - just _some_thing. A whole of little things come together to make something great.