panic: IP header len too small

[Allan Fields]

On Tue, Jul 06, 2004 at 12:57:14PM -0700, Jeffrey Hsu wrote:
> Now I'm concerned.  Which TCP/IP stack is generating the illegal
> short IP packet?  If the sending host, the one that didn't panic,
> is running DragonFly, please let us know so we can look into it
> further.  Thanks.

It's a FreeBSD 5 box acting as a router.  The NFS server is also
a FreeBSD machine on the LAN.

What is worthwhile mentioning is that this an ad-hoc setup using an
old laptop temporarily connected w/ plip (laplink) in place of
proper ethernet due to problems w/ setting up ethernet (interface
works w/ NetBSD CD so can be made to work).

The panics are reproduceable and occur after random interval (1-15
minutes) of IP activity (panics happen during FTP and ping -f).  I
can't recall whether I've tried a similar exercise with FreeBSD 4
installed.

Setup is:
laptop:             gateway host:           NFS server:
 DragonFly           FreeBSD 5               FreeBSD 5.2.1
 10.1.0.2 <--plip--> 10.1.0.1
 (Used to be         10.0.0.5 <--ethernet--> 10.0.0.2
  FreeBSD 4.x)

laptop# ping 10.0.0.2
64 bytes from 10.0.0.2: icmp_seq=0 ttl=63 time=4.334 ms
64 bytes from 10.0.0.2: icmp_seq=1 ttl=63 time=3.607 ms
64 bytes from 10.0.0.2: icmp_seq=2 ttl=63 time=3.874 ms
. ..
^C
--- 10.0.0.2 ping statistics ---
135 packets transmitted, 135 packets received, 0% packet loss
roud-trip min/avg/max/stddev = 3.598/3.759/4.344/0.118 ms


I'm not sure if in FreeBSD 5 the plip interface is in a working
state at this time and it might have severe locking and other issues.
I could try w/ 802.11, but DragonFly support for pcmcia/pc-card
slots doesn't work on this machine.

pccardd returns fatal error: no PC-CARD slots.  So I could look
into what has changed to drop support w/ upgrade from FreeBSD-4.

Thanks,
-- 
 Allan Fields, AFRSL - http://afields.ca
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