Subject: Re: Tap(4) interface in NetBSD?
To: Manuel Bouyer <>
From: Brian Buhrow <>
List: current-users
Date: 04/28/2003 11:37:55
	Hello Manuel.  I'm willing to consider adding this functionality to
the if_tun driver, but I have a number of questions which I'd like 
to ask and which I'd like some feedback on before I dive too deep.

1.  I think it would be good to provide interoperability with the FreeBSD
implementation of the tap(4) driver,  What this means is that we need to
provide a /dev/tapX device as well as a /dev/tunX device.  Should that be
done by selecting a range of minor device numbers for the tapX interface?

2.  Can I use the cloning feature with ethernet type devices?  It strikes
me that cloned network devices want to attach at the IP layer rather than
the ethernet layer.  Is this just  lack of understanding on my part?

On Apr 28,  3:46pm, Manuel Bouyer wrote:
} Subject: Re: Tap(4) interface in NetBSD?
} On Mon, Apr 28, 2003 at 09:41:09AM -0400, Andrew Brown wrote:
} > since "extending" the creat/destroy interface might be a little
} > tricky, how about asserting that all programs must go through three
} > phases:
} > 
} > 	open /dev/tun#
} > 
} > 	set required options, specify link layer, etc
} > 
} > 	set interface to "up" and begin operating
} This is how tun works these days. Changing a tun device from point to point
} to broadcast has to be done via ioctl on the control device, before the
} interface is turned up.
} --
} Manuel Bouyer, LIP6, Universite Paris VI. 
}      NetBSD: 24 ans d'experience feront toujours la difference
} --
>-- End of excerpt from Manuel Bouyer