bce discard frame w/o leading ethernet header and polling (broken?) 7.1-beta2

Jung-uk Kim jkim at FreeBSD.org
Tue Nov 18 10:44:29 PST 2008

On Tuesday 18 November 2008 01:01 pm, security wrote:
> I'm building a WAN emulation box based on 7.1-beta2-ipfw and
> dummynet. The config is basically a router-on-a-stick.  The server
> (FBSD rtr) has two nics which connect to two different switches,
> but both switch ports are in the same untagged interconnected vlan.
>  All the other test boxes in the network are also in the same vlan,
> but broken into different nets.  The different nets are spread
> across the two nics as primary and alias ip address in different
> nets.  I've been getting "bursts" (maybe 8-20 at a time) of the
> discard frame messages.  Mostly on bce1 but I've seen them on bce0
> also. bce1 is probably the busier of the 2 currently. As a shot in
> the dark, I disabled polling system wide and the messages seemed to
> have stopped.

Please try the latest driver from RELENG_7.  The following commit 
seems interesting:


Jung-uk Kim

> thanks
> jim
> kernel: bce1: discard frame w/o leading ethernet header (len
> 4294967292 pkt len 4294967292)
> ipfw/dummynet/pipes are being used to rate limit traffic by src/dst
> ip address.
> The FreeBSD box uses the broadcom bcm5706s gigE interfaces.
> class=0x020000 card=0x310c103c chip=0x16aa14e4 rev=0x02 hdr=0x00. 
> Based on some readings, I've got the following mods in place:
> i386 sources running on a 2 x dual core athalon64 cpus, 4 cores
> active. 8gig of mem available, but only 4 in use
> kernel
> i486 and i586 commented out
> nfs options commented out
> fbsd 4 and 5 commented out
> hz=1000
> ipfirewall
> ipfirewall_default_to accept
> dummynet
> eisa commented out as well as the older nics
> sysctl settings
> kern.polling.enable=1 (setting this to 0 seems to fix the problem,
> but leaves the cpu's busier)
> kern.ipc.maxsockbuf=16777216 (not sure this helps much in the case
> of a rtr) net.inet.ip.forwarding=1
> net.inet..tcp.sendbuf_auto=1
> net.inet..tcp.sendbuf_max=16777216
> net.inet..tcp.recvbuf_auto=1
> net.inet..tcp.recvbuf_max=16777216
> net.inet.tcp.rfc1323=1
> net.link.ether.inet.log_arp_wrong_iface=0 (to suppress the arp
> messages)
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