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Date:      Sun, 6 May 2001 11:02:53 -0400
From:      "Matthew Emmerton" <matt@gsicomp.on.ca>
To:        "Brian Somers" <brian@Awfulhak.org>
Cc:        <freebsd-net@freebsd.org>
Subject:   Re: Netgraph/fxp/pppoe causing system panic in 4.3 stable. 
Message-ID:  <007b01c0d63d$a0adaea0$1200a8c0@gsicomp.on.ca>
References:  <200105061425.f46EPMB56450@hak.lan.Awfulhak.org>

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However, in 3.4, netgraph + pppoe didn't require "ifconfig iface up" in
rc.conf in order to use PPPoE, but that requirement has been in 4.x from the
beginning.  The big question is, why did this behaviour change? (Insert POLA
argument here.)

I can't really see why we shoudl be forcing users to "ifconfig iface up"
their ethernet NIC in rc.conf, when it's really abstracted away by PPPoE --
netgraph should look after bringing the interface up, and perhaps complain
loudly if someone should down it while it's being used.  (I'm thinking that
the control of the interface should lie under netgraph and it's tools, not
standard userland tools like ifconfig, for "abstracted" cases like this.)

> I guess the key question is whether PPPoE should use the interface if
> it's not IFF_UP.
>
> If it shouldn't, the interface should drop the data on the floor.
>
> If it should, the interface should just deal with it.
>
> I'd suggest that we should fix the guilty interfaces and
> automatically ``ifconfig iface up'' from the rc script.  ppp
> shouldn't be bringing the interface up itself.
>
> > I'm not sure if it's just fxp0 -- a few weeks ago a few people reported
this
> > very same problem with PPPoE for cards other than fxp0.
> > Adding an ifconfig_xxx="up" to /etc/rc.conf (as suggested by an article
on
> > daemonnews or freebsddiary) "fixed" the problems for the people that I
heard
> > about -- but you're right that it isn't the best solution.
> >
> > The problem is this:  if a card is down, it's because a) it's never been
> > configured or b) it was downed manually.  In the former case, we want
PPPoE
> > to initialize and start using the card (since you'd never have to
initialize
> > the NIC being used for PPPoE.)  However, in case b), the driver should
just
> > ignore the data.
> >
> > How can we differentiate between case a) and case b)?  I could see some
> > admins getting pretty peeved if they 'ifconfig down fxp0' and then a few
> > seconds later, PPPoE brings the interface back up to send data. (Of
course,
> > it would be better to kill the PPPoE daemon first before doing that,
but...)
> >
> > > PPPoE now brings the interface IFF_UP before using it, but this isn't
> > > the right solution (someone could manually down it again).
> > >
> > > fxp should just drop data if it's not up.
>
> --
> 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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