Detecting LINK_UP / LINK_DOWN events

[Sastry Tumuluri]

> -----Original Message-----
> From: Tom Judge [mailto:tom at tomjudge.com] 
> Sent: Tuesday, May 22, 2007 12:01 AM
> To: Sastry Tumuluri
> Cc: freebsd-net at freebsd.org
> Subject: Re: Detecting LINK_UP / LINK_DOWN events
> 
> Sastry Tumuluri wrote:
> > Friends,
> > 
> > I am trying to catch and do some extra processing on LINK_UP and 
> > LINK_DOWN events for my net interfaces (e.g., notify my 
> admin, log the event, ...).
> > Tried this on both FreeBSD 6.1 and on FreeBSD 6.2.
> > 
> > I tried using the devd.conf file with the following code (shows 
> > LINK_DOWN; wrote similar stuff for LINK_UP):
> > 
> > notify 10 {
> >    match   "type"    "LINK_DOWN";
> >    action   "logger -s alert: Caught LINK_DOWN on dev: $device-name
> > subsys:  $subsystem";
> > };
> > 
> > Didn't work. I tried the above with both strict match conditions 
> > (using vendor, device and class matches) as well as very 
> general (like the above).
> > Didn't work.
> > I ran killed devd and ran it in the foreground with "devd 
> -dD". Then I 
> > logged into a different pty and used
> > ifconfig lnc0 down     #(lnc0 is my ethernet device).
> > devd doesn't even seem to catch the event (no output at all 
> - both on 
> > screen and in syslog).
> > 
> > 
> > On the other hand, "nomatch" and "attach" messages do seem to get 
> > through (I wrote similar stuff for nomatch & attach, and they are 
> > showing up at bootup and in syslog).
> > What could I be doing wrong?
> > 
> 
> Have you had a look at net/ifstated in ports?
> 
> Tom
> 

Thanks, Tom! Though I had not heard of ifstated before this, it looks
interesting. I've managed to quickly get the latest port and install it
without any hassles - but am still a bit short on documentation - esp., how
the .conf file works, and how to make ifstated work for me. I haven't used
carp so far; and am not sure whether I need to, if all I want is a simple
"notification / logging". Any suggestions?

On the other hand, I am still curious why devd didn't work in the first
place. Is it a "futuristic" feature already advertised (in the devd.conf
file, there are examples of LINK_UP/LINK_DOWN that make it look like it
should work)? Or a case for better documentation?

Regards,

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