Wait for carrier in /etc/rc.d/defaultroute

[Jeremy Chadwick]

On Wed, Sep 29, 2010 at 12:46:28AM -0700, Jeremy Chadwick wrote:
> On Mon, Sep 27, 2010 at 08:23:52PM -0700, Doug Barton wrote:
> > On 9/24/2010 5:04 PM, Ed Maste wrote:
> > >/etc/rc.d/defaultroute currently bails immediately if all interfaces
> > >set to use DHCP have no carrier.  This caused grief at work as it takes
> > >some time for link to be established, and defaultroute ran before this
> > >happened.  The rest of rc.d/ ran then before DHCP could assign an
> > >address and route.
> > >
> > >The attached patch introduces a defaultroute_carrier_delay variable
> > >and a change to /etc/rc.d/defaultroute to wait that long before bailing
> > >out if there are no interfaces with carrier.  With the default settings
> > >defaultroute will wait for five seconds to see if any interface gets
> > >carrier.  The original 30 second wait for a default route to appear is
> > >unchanged.
> > >
> > >Any comments?  I'll commit it sometime next week if there's no concern.
> > 
> > There was a more generic solution floating around fairly recently,
> > from Jeremy Chadwick. The thread on this list starts back in april,
> > but the latest version of the script appeared in june, so you might
> > want to start there. I used versions of that script for most of this
> > calendar year, and offered to commit it if the rc.conf.5 update was
> > written.
> > 
> > Jeremy, if you've done that bit and I lost track, apologies, my
> > FreeBSD time has been super limited lately, but it's on the upswing
> > at the moment, so maybe you could update us?
> 
> Ack, I forgot all about this (and despite recommending the script to
> someone on the lists a couple weeks ago)!  The script Doug's referring
> to is available below, and should be placed into /usr/local/etc/rc.d (be
> sure to chmod 755/555 it as well):
> 
> http://jdc.parodius.com/freebsd/netwait
> 
> Example usage in /etc/rc.conf:
> 
> netwait_enable="yes"
> netwait_ip="4.2.2.1 4.2.2.2"
> netwait_if="em0"
> netwait_timeout="15"
> 
> This version lacks some of Doug's recommended changes (some minor syntax
> changes and a more realtime indicator of what's going on by printing
> dots/periods) -- I'll dig up Doug's Email from a while back and make
> some time to implement his recommendations.

I misread Doug's proposed changes -- it's not to print dots/periods to
indicate status, I misread the patch.  :-)

I've implemented his changes and the above script has been updated to
include them.  We should be good to go, aside from removal of a couple
commented out default variables near the top of the script.

> The idea in the long-run is to get this script committed to the base
> system (e.g. /etc/rc.d), have rc.conf(5) updated to mention the
> variables, in addition to src/etc/defaults/rc.conf.
> 
> Furthermore, I should probably file a PR for all of this...

I just spent the past couple hours doing the rc.conf.5 and
defaults/rc.conf modifications.  These, as well as the netwait script
itself, should be reviewed by those more familiar with the base system
rc(8) stuff (hi Doug.  :-) ).  Meaning: I'm not sure where the default
values should be set.

The official PR, which contains URLs to the patches and the script
itself.  Not showing up on the web yet, but I got the GNATS response.

http://www.freebsd.org/cgi/query-pr.cgi?pr=151063

-- 
| Jeremy Chadwick                                   jdc at parodius.com |
| Parodius Networking                       http://www.parodius.com/ |
| UNIX Systems Administrator                  Mountain View, CA, USA |
| Making life hard for others since 1977.              PGP: 4BD6C0CB |