Lista de NetBSD current <list11@sepc.edu.mx> wrote:
> I am running -current (Feb 2 2002) i386, my kernel was
> compiled with the "altq most common options". After to run
> /etc/rc.d/altqd start, I got a lot of error messages:
> 
> altq_etherclassify: headers span multiple mbufs: 14 < 34
> altq_etherclassify: headers span multiple mbufs: 14 < 34
> altq_etherclassify: headers span multiple mbufs: 14 < 34
> altq_etherclassify: headers span multiple mbufs: 14 < 34
> 
> I have compiled the kernel again with NMBCLUSTERS=4096
> and "make USETOOLS=no depend all", but when I reboot the
> machine and start altqd, the same messages appears,
> exactly with the numbers 14 and 34 (a lot of times).

short answer: you can comment out the corresponding printf()
in altq_etherclassify() in sys/net/if_ethersubr.c.

longer answer:
major protocols reserve a leading space when they allocate a mbuf so
that an ethernet header fits into the first mbuf.
apparently, some types of control protocols don't reserve a leading
space for an ethernet header.
I can't tell what protocol causes this for you.  (one I know of is the
bridge control protocol in OpenBSD.)

when altq_etherclassify() finds the ethernet and ip headers are not in
the fisrt mbuf, it prints a warning message, just gives up classifying
the packet and puts the packet into a default class.
since these protocols are not too important for traffic control,
just supressing the warning message should be ok, at least for now.

-Kenjiro