Re: SLIP coexisting with serial data?

[Steven Bellovin <smb%cs.columbia.edu@localhost>]

On Oct 10, 2010, at 4:41 40AM, der Mouse wrote:

> I have a situation in which it would be useful to run SLIP on a serial
> console.  Obviously, this won't work very well at present.  (The
> machine has only one serial port and no useful network interfaces.)
> 
> I was looking at improving if_sl.c to support encapsulating "normal"
> serial data on the SLIP's tty as packets, thus merging it into the
> packet stream.  I ran into some problems, but think I can handle them;
> I'm writing to ask if there's any interest from anyone else in this
> sort of thing, in upgrading SLIP to support "normal" serial output.
> 
> I was thinking of making this another protocol type, akin to what I
> mentioned (probably on tech-net) back in '02 - I just now (finally)
> filed kern/43959 containing patches to support v6 as well as v4,
> something that's easy compared to making the tty still work as a tty,
> but which includes a good deal of multi-protocol scaffolding that's
> semi-necessary for the way I've been envisioning doing serial data.
> 
Given how rare the situation is, maybe it's best to do the 
encapsulation/decapsulation in user mode, and feed into SLIP via a pty.  (I 
also suspect that the speeds are low, but I know you often run older machines.)


                --Steve Bellovin, http://www.cs.columbia.edu/~smb