Date: Sun, 19 Mar 2000 17:00:02 -0800 (PST) From: Brian Somers <brian@Awfulhak.org> To: freebsd-bugs@FreeBSD.org Subject: Re: kern/17494: Two issues with the tun device Message-ID: <200003200100.RAA85606@freefall.freebsd.org>
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The following reply was made to PR kern/17494; it has been noted by GNATS.
From: Brian Somers <brian@Awfulhak.org>
To: scott_long@btc.adaptec.com
Cc: FreeBSD-gnats-submit@FreeBSD.ORG, brian@hak.lan.Awfulhak.org
Subject: Re: kern/17494: Two issues with the tun device
Date: Mon, 20 Mar 2000 00:54:45 +0000
> 1. the ifnet structure for the tun device is not created at attach time like
> it is for other network drivers. Instead, it is created when the device is
> opened, if it hasn't already been created in a previous open. This behaviour
> causes my program to not see the tun device unless a program like ppp(8) is
> run first, which defeats one of the goals of this program: to control dialup
> networking. Comparing code in if_[tun|ppp|sl|lo].c shows that all but tun
> create the ifnet structure from within their respective attach routine. But
> on the other hand, if_tun.c uses make_dev while the others do not. Making
> if_tun.c resemble the others is a trivial task, but I am not sure what would
> be lost by eliminating make_dev (which requires a dev_t argument that attach
> cannot supply, if I understand things correctly).
Interfaces are moving towards being a lot more dynamic than they have
been in the past. This new behaviour of the tun device is IMHO the
way forward rather than a problem that has to be fixed.
The way things currently are, you don't even need a tun device
specified in your kernel. The module is as functional and will
create new interfaces and softcs as required. In the future, I
would think it's likely that the last close() will remove the
interface.
Why does you program require the interfaces existence up front ?
Surely this is where the problem lies ?
--
Brian <brian@Awfulhak.org> <brian@[uk.]FreeBSD.org>
<http://www.Awfulhak.org>; <brian@[uk.]OpenBSD.org>
Don't _EVER_ lose your sense of humour !
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