Re: question regarding tap/tun devices


On Mon, 29 May 2006, Brooks Davis wrote:

On Sun, May 28, 2006 at 08:33:32PM +0200, Goran Gajic wrote:
I'm running 7.0-CURRENT build Thu May 25 23:17:10 CEST 2006 GENERIC config.
While playing with dynamips emulator which uses tap I've noticed that
ifconifg tun0 create or ifconfig tap0 create doesn't work (this doesn't
have anything to do with emulator which works great).

These interfaces don't use the network interface cloning interface and thus can not be created with ifconfig. This should be fixed, but the /dev based cloning hackes they use make this difficult.

I've never quite understood if this is a problem or a benefit. Devfs-cloning of tap and tun are very convenient from an application writer perspective -- you just open /dev/tap or /dev/tun, and magic happens. With our current ifnet cloning interface, is it possible to say "atomically create and return the next available interface number"?

Robert N M Watson
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