Subject: Re: Moving ethfoo in the main tree
To: Daniel Carosone <>
From: Quentin Garnier <>
List: tech-kern
Date: 12/14/2004 23:12:43
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On Wed, Dec 15, 2004 at 08:15:22AM +1100, Daniel Carosone wrote:
> On Tue, Dec 14, 2004 at 07:32:33AM -0800, Jason Thorpe wrote:
> > How about using ifmedia to determine the link type to emulate in tun?
> I like this idea, and would suggest taking it further if it makes sense.
> As I said elsewhere, on a number of occasions I've wished to be able
> to bridge(4) between a local ethernet and a gre tunnel, for transport
> of layer2 frames across a WAN to a remote site. I can do this with
> cisco gear, and it has all sorts of valuable uses I can elaborate upon
> request. Being able to do it with NetBSD machines instead, or with
> NetBSD at one end and a cisco at the other, would enhance this
> usefulness and applicability.
> So the current ethfoo/tap/tun/whatever interface semantics are
> partially relevant, but don't get me all the way there - I'd still
> need some userspace process (or perhaps ipf fastroute hackery?) to
> copy the frames from this device to the gre interface and back again.
> If instead this "synthetic ethernet" property could be something in
> the ifmedia layer, that could be applied equally to tun or gre (or yet
> some other example) in a generic fashion, so it would work with
> bridge(4), I think we'd have a much cleaner and better solution.
> Perhaps these requirements are a little different, and merit a
> different solution specifically in gre itself, but if a generic
> solution is feasible I'd like to encourage that path.

I can't say I know it enough to be positive on this, but isn't
netgraph(4) exactly what you want?

Quentin Garnier - -
"Commala-come-five! / Even when the shadows rise!
To see the world and walk the world / Makes ya glad to be alive."
Susannah's Song, The Dark Tower VI, Stephen King, 2004.

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