On Tue, May 05, 2020 at 10:51:40AM +0200, Claudio Jeker wrote:
> On Tue, May 05, 2020 at 09:07:34AM +0100, Richard Chivers wrote:
> > After some more work this morning we have managed to extract the
> > information from tcpdump of the full LS-Update packet, we couldn't see it
> > on bsd, but running:
> >
> > tcpdump -v -r ~/Downloads/ospf.pcap on osx did the trick.
> >
> > What we are seeing is that a pair of firewalls are both sending updates
> > like this:
> >
> > 07:16:09.346525 IP (tos 0xc0, ttl 1, id 47473, offset 0, flags [+], proto
> > OSPF (89), length 1500)
> > x.x.x.x > ospf-dsig.mcast.net: OSPFv2, LS-Update, length 1480 [len 1672]
> > Router-ID x.x.x.x, Backbone Area, Authentication Type: simple (1)
> > Simple text password: dslkfjld, 1 LSA
> > LSA #1
> > Advertising Router x.x.x.x, seq 0x8000006e, age 0s, length 1624
> > Router LSA (1), LSA-ID: x.x.x.x
> > Options: [External]
> > Router LSA Options: [ASBR]
> > Stub Network: 10.128.32.128, Mask: 255.255.255.128
> > topology default (0), metric 10
> > Stub Network: 10.128.9.0, Mask: 255.255.255.128
> > *{ another 50 or so networks here}*
> >
> > Each time we get one of these updates the DR logs the lsa_check: bad age.
> >
> > Another 5 or so seconds later the same LS-Update comes in with the same seq
> > number. This appears to continue indefinitely. Our only fix appears to be
> > restarting ospfd on the routers.
> >
> > Does anyone have an idea what is going wrong here?
> >
> > Something we have considered being a problem is that we do have many
> > interfaces, we have 90 or so, so the LS-Update packets are quite large and
> > do get fragmented, as we are using a 1500mtu.
> >
> > The fact that ospfd sees the age and complains though makes us think this
> > is not a problem.
> >
>
> Looking at the tcpdump output there is something strange with the various
> reported length fields. Is it possible to get the raw packet dumps?
>
Can you try the following diff and see if it fixes the issue?
--
:wq Claudio
Index: lsupdate.c
===================================================================
RCS file: /cvs/src/usr.sbin/ospfd/lsupdate.c,v
retrieving revision 1.47
diff -u -p -r1.47 lsupdate.c
--- lsupdate.c 19 Nov 2019 09:55:55 -0000 1.47
+++ lsupdate.c 5 May 2020 09:20:50 -0000
@@ -186,7 +186,7 @@ add_ls_update(struct ibuf *buf, struct i
return (0);
}
- lsage = ibuf_reserve(buf, 0);
+ lsage = ibuf_reserve(buf, len);
if (ibuf_add(buf, data, len)) {
log_warn("add_ls_update");
return (0);
