Path: utzoo!attcan!uunet!cs.utexas.edu!asuvax!ncar!midway!oddjob!matt
From: matt@group-w.uchicago.edu (Matt Crawford)
Newsgroups: comp.unix.wizards
Subject: Re: Datagrams Outside the Kernel
Message-ID: <1990Jul2.190738.29732@midway.uchicago.edu>
Date: 2 Jul 90 19:07:38 GMT
References: <8009@inco.UUCP> <414@minya.UUCP>
Sender: news@midway.uchicago.edu (News Administrator)
Reply-To: matt@group-w.uchicago.edu (Matt Crawford)
Organization: If you lived here you'd be home by now
Lines: 22
In-Reply-To: jc@minya.UUCP (John Chambers)

In article <414@minya.UUCP>, jc@minya (John Chambers) writes:
) I'll second this request.  I've been asked whether I can build an
) application which, in effect, "volunteers" to handle any IP address
) that the kernel doesn't know what to do with.  In perusing TFM, I
) haven't found any hint that this is possible.  
) Any better ideas?  Is Unix up to the task?

I think I know how this could be done.  I once wrote a sort of a
"chimeral" device driver which provided open()/read()/write() access and
was also a network interface.  In that case it was meant to be used just
one way or the other at any given time, but in your case I would make
the if_output() routine hand packets to the read queue of the character
device.

Then you'd configure a default route to point to this interface.  Voila!
Packets addressed to "any IP address that the kernel doesn't know what
to do with" go to the process reading the character device.

You did say "build an application," while the above needs a new device
driver, but since you don't need source to your kernel, this probably
counts as a solution.
				Matt Crawford