> I intended to say it will be used within bpf(4), i.e. using bpfattach()
> but not ifattach().

I recalled another possibility discussed with enami-san.

Make existing wireless lan interface to handle raw 802.11 only and
create a dynamic adaptation layer to handle ethernet emulation.
	ex) 
	    ifconfig wi0 nwid SSID nwkey WEPKY up
	    ifconfig wlan0 create wlanif wi0
	    dhclient wlan0		# enable and use the interface
	    tcpdump -i wlan0		# capture ethernet emulation
	    brconfig bridge0 add wlan0	# add to ethernet bridge
	    tcpdump -i wi0		# capture raw 802.11 frame
	    ifconfig wi0 a.b.c.d	# should fail?

Atsushi Onoe