[Twisted-Python] adding a new connection type

[Eric C. Newton]

Itamar Shtull-Trauring <twisted at itamarst.org> writes:
> Well, first of all, what does it run over?  

X.25.  Be afraid.

> And in what languages is it written?  

It runs in Python of course.

> And, what is it good for?

X.25 is an international standard for wide area communications widely
adopted by companies in the 1970's and early 80's using
packet-oriented, synchronous serial communications devices.

I'm using Linux, and playing with 2-year-old patches for version 2.4
of the kernel which enables me to play with the API over a loopback
device.

Sometimes it even works.

The linux X.25 API is broadly based upon BSD sockets.  Unfortunately,
the python sockets module only really supports INET and UNIX domain
addresses.  I've written my own C module to provide an alternative
interface because doing X.25 is just so much fun.

I've managed to get past all the Twisted (.tap) stuff and I've got the
process accepting these faux X.25 connections and data is flying back
and forth.  I subclassed from the tcp.Port class, and re-wrote the
startListening() method.  I haven't tried the client side of
things yet.

Among other things, I needed to add a shutdown() method, which socket
provides and Twisted seems to need.

-Eric