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From: mah@wu-wien.ac.at (Michael Haberler)
Newsgroups: comp.unix.internals
Subject: Re: SLIP without kernel modification
Message-ID: <1991Jun26.071138.1425@swdsrv.edvz.univie.ac.at>
Date: 26 Jun 91 07:11:38 GMT
References: <128234@tyrell.stgt.sub.org> <800@minya.UUCP>
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In article <800@minya.UUCP>, jc@minya.UUCP (John Chambers) writes:

|> Recently, I got my hands on a driver for Ultrix that is something that
|> I've wished was in the IP package from the  start.   It's  called  the
|> "PNI" driver, which stands for Pseudo-Network Interface. What it is is
|> a network equivalent to a pty:  It looks like a network interface from

I've been looking into Compressed SLIP for Interactive/386 and came to the
same conclusion for different reasons. 

While theoretically elegant (one could imagine pushing a SLIP framing
module onto a tty, and then a VJ compressor on top, and link this under
the IP multiplexer at runtime) this doesnt work because the Lachman
netd (the program which sets up the STREAMS stacks for IP) doesnt allow
pushing STREAMS modules, only linking them under/over Multiplexer modules.
Great idea, I though, neat, simple and wrong :-(

So the alternatives are to munge evrything from tty access, slip framing to
VJ compression into a single STREAMS device driver, which I'm lacking 
information to do at the tty level. Also, this looks like serious debugging
ahead. 

The other alternative is something like you mentioned, and I finally 
have something close to that for ix/386. It's based on a SLIP driver done
by John Joannides at cmu. It does the same thing-go back to userland for
SLIP framing and such. 

What I have is'nt ready for release yet, but I plugged a memory leak and
reverse-engineered some of the socket ioctls for network interfaces. So
a dedicated hacker should send me mail.

- michael


-- 
Michael Haberler 		mah@wu-wien.ac.at,  mah@awiwuw11.bitnet
University of Economics and Business Administration
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