[e2e] Looking for a User level TCP implementaion

[Jay Lepreau]

The OSKit (SOSP'97) contains lots of completely-separated OS
components, that can be run either in other kernels, on raw hardware,
or in user mode.  Adaptors for the latter two environments
(x86/StrongARM, Linux/FreeBSD) are provided for you.

We and many others have used it a lot both for research and
production.  The FreeBSD TCP/IP stack is one of the components, and
can be used alone.

   http://www.cs.utah.edu/flux/oskit/