Netgraph. panic in kernel

[Alexey Lukashin]

Hi all,

I'm studying how Netgraph system works and trying to write my own 
netgraph node similar to ng_bridge.
It catches packets from lower ng_ether hooks and transmits it to other 
interfaces using mac address hashtable.

Packet processing in my node implemented similar to ng_bridge_rcvdata() 
in ng_bridge.c.
I don't do anything with packet. I don't modifying packet header, I only 
send it to another interface.

My interfaces are working in promiscuous mode with autosrc=0.

But sometimes (after one or two hours working in network) I have an 
error with message:

"rl1: discard frame w/o packet header"

After it, my system halts.

Is anybody knows, where the problem can be? When does this message appears?

(system is FreeBSD 7.1-STABLE)

Thank you.

--
Best regards,
    Alexey Lukashin
Saint-Petersburg, Russia