Re: HEADSUP: OpenBSD dhclient incoming

M. Warner Losh wrote:
> In message: <20050615061009.GA11914_at_odin.ac.hmc.edu>
>             Brooks Davis <brooks_at_one-eyed-alien.net> writes:
> : On Wed, Jun 15, 2005 at 07:42:48AM +0400, Vladimir Grebenschikov wrote:
> : > ? ??, 14/06/2005 ? 20:57 -0400, Matthew Emmerton ?????:
> : > > On Tue, 14 Jun 2005, Brooks Davis wrote:
> : > > 
> : > > > On Tue, Jun 14, 2005 at 10:01:45AM +0400, Vladimir Grebenschikov wrote:
> : > > >> ? ??, 06/06/2005 ? 20:46 -0700, Brooks Davis ?????:
> : > > >>> I'm about to start importing the OpenBSD dhclient and required
> : > > >>> support in /etc.  I will unhook dhclient from the build while I work so
> : > > >>> there shouldn't be much breakage for most people
> : > > >>
> : > > >> I have strange behavior of new dhclient + devd:
> : > > >>
> : > > >> just after boot (with ethernet plugged) I have no devd events about
> : > > >> state of media and have interface down, but after first ifconfig (even
> : > > >> without parameters, even executed by any user) "link state chages to UP"
> : > > >> event appears and devd starts dhclient on interface.
> : > > >>
> : > > >> I do not think that it is desired behavior.
> : > > >>
> : > > >> my rc.conf, related to this:
> : > > >>
> : > > >> ifconfig_fxp0="dhcp"
> : > > >> network_interfaces="lo0"
> : > > >> devd_enable="YES"
> : > > >>
> : > > >> Probably I need to comment network_interfaces line, but anyway, now it
> : > > >> works strange.
> : > > 
> : > > Shouldn't you have network_interfaces="lo0 fxp0" in order for the rc 
> : > > scripts to run the appropriate ifconfig or dhclient command for each 
> : > > interface?
> : > 
> : > Probably yes (it works), but why first /sbin/ifconfig, issued by uid!=0
> : > triggers dhclient ?
> : > 
> : > I think behavior should be consistent, either rc.d/netif relay only on
> : > devd events and does not depends on network_interfaces= or rc.d/netif
> : > should relay on network_interfaces= and ignore not mentioned interfaces.
> : > 
> : > Also devd's IFUP event should not depend on user's /bin/ifconfig issued
> : > (or not issued) by hands.
> : 
> : There are two issues here.  First, if we're going to keep
> : network_interfaces around, /etc/rc.d/dhclient should honor it and
> : not start dhclient on interfaces not in either network_interfaces or
> : removable interfaces.  Second, running ifconfig should not be triggering
> : link events.  That makes no sense.  I'll have to see if can replicate
> : that, I'm a bit dubious.
> 
> ifconfig fxp0 1.2.3.4/24
> 
> will kill dhclient every time for me.

There are several drivers that have issues with reliably generating LINK 
state up/down events.  The bge driver does not work right for me with a 
5704 (I think) part--the gige part in my Dell 600m.  I tried discussing 
this this with wpaul but he's out of touch these days.

> 
> I've also been seeing weirdness with the new dhclient when i move from
> network to network on boot when I have the 'old' lease around but no
> cable connected.  I'll see if I can replicate this enough to submit a
> report.

I've noticed one issue.  If you mark an interface down then dhclient 
exits but any assigned ip address is not removed.  This is a change from 
the previous dhclient and something I thought I'd fixed (but clearly 
not).  OTOH brooks pointed out that leaving the ip address around means 
tcp sessions don't immediately die so if you reconnect and reacquire the 
same lease your sessions can be revived if they were idle.

	Sam