Detecting LINK_UP / LINK_DOWN events
Sastry Tumuluri
sas3 at tumuluri.name
Wed May 23 05:46:50 UTC 2007
Finally got ifstated working the way I wanted. Thanks to Tom & Nikos.
The port included a man page for ifstated(8) - but was not sufficient
to get a newbie like me going. I found a good addition on openbsd
man pages ifstated.conf(5).
br,
==Sas3==
> -----Original Message-----
> > -----Original Message-----
> > From: Nikos Vassiliadis [mailto:nvass at teledomenet.gr]
> > Sent: Tuesday, May 22, 2007 2:58 PM
>
> > On Tuesday 22 May 2007 12:19, Sastry Tumuluri wrote:
> > > > -----Original Message-----
> > > > From: Tom Judge [mailto:tom at tomjudge.com]
> > > > Sent: Tuesday, May 22, 2007 12:01 AM
>
> > > > 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: $subsystem";
> > > > > };
> > > > >
> > > > > Didn't work. I tried the above with both strict match
> > conditions
> > > > > (using vendor, device and class matches) as well as very
> > > >
> > > > general (like the above).
> > > >
> > > > > Didn't work.
> > > > > I ran killed devd and ran it in the foreground with "devd
> > > >
> > > > -dD". Then I
> > > >
> > > > > logged into a different pty and used
> > > > > ifconfig lnc0 down #(lnc0 is my ethernet device).
> > > > > devd doesn't even seem to catch the event (no output at all
> > > >
> > > > - both on
> > > >
> > > > > screen and in syslog).
> > > > >
> > > > >
> > > > > On the other hand, "nomatch" and "attach" messages do
> > seem to get
> > > > > through (I wrote similar stuff for nomatch & attach,
> > and they are
> > > > > showing up at bootup and in syslog).
> > > > > What could I be doing wrong?
> > > >
> > > > Have you had a look at net/ifstated in ports?
> > > >
> > > > Tom
> > >
> > > Thanks, Tom! Though I had not heard of ifstated before
> > this, it looks
> > > interesting. I've managed to quickly get the latest port
> > and install
> > > it without any hassles - but am still a bit short on
> > documentation -
> > > esp., how the .conf file works, and how to make ifstated
> > work for me.
> > > I haven't used carp so far; and am not sure whether I need
> > to, if all
> > > I want is a simple "notification / logging". Any suggestions?
> > >
> > > On the other hand, I am still curious why devd didn't work in the
> > > first place. Is it a "futuristic" feature already
> > advertised (in the
> > > devd.conf file, there are examples of LINK_UP/LINK_DOWN
> > that make it
> > > look like it should work)? Or a case for better documentation?
> >
> > Did you try pulling the plug?
> > LINK events refer to the change of link status, not the "UP"
> > status. That is the "status: active" line .
> >
> > nik:0:~$ ifconfig fxp0
> > fxp0: flags=8843<UP,BROADCAST,RUNNING,SIMPLEX,MULTICAST> mtu 1500
> > options=8<VLAN_MTU>
> > inet 192.168.1.71 netmask 0xffffff00 broadcast 192.168.1.255
> > ether 00:0c:f1:b9:38:50
> > media: Ethernet autoselect (100baseTX <full-duplex>)
> > status: active
> >
> > HTH, Nikos
> >
>
> That solved one mystery, Nikos! Yes, the LINK_UP/LINK_DOWN do
> seem to refer to the status of the physical media (plugged in
> or out). While at it, I also found that
> ifconfig em0 down (not pulling out the media, just the command)
> does not send any status message (perhaps a driver
> feature? Not sure), but ifconfig em0 up
> does send a LINK_DOWN first and then a LINK_UP. This
> doesn't seem to
> have any relation to whether or not the IP address is
> there or -aliased.
>
> It still leaves me with my original problem that of
> "detecting changes to the interfaces and logging them /
> sending alerts". This needs to work for me for any
> Interface: real / psuedo (is that word for ppp0/tun0/etc...?)
> and any type of
> change: e.g. ip-addr change thru dhcp/pppoe/static etc.. :-(
> So I guess I'll keep plugging away at ifstated (carp or
> no-carp), then!! :-)
>
> Regards,
>
> ==Sas3==
>
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3:49 PM
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