>> 	sys/net/if_ethersubr.c has IFF_SIMPLEX checks for broadcast cases
>> 	(M_BCAST) and not for multicast (M_MCAST).  are there specific
>> 	reasons for this?   if multicast handling was introduced after
>> 	IFF_SIMPLEX is invented, it may be a bug in L2 multicast support.
>Unless explicitly disabled, multicast packets are looped back in L3,
>aren't they?

	oops, you right.  i still have one question - should we put a check
	for "multicast outgoing packet looped back to myself" packets,
	in sys/net/if_ethersubr.c?  we have a couple of ethernet
	chips/drivers that do this.  for example, see sys/dev/ic/smc91cxx.c.
	(the chip loops outgoing multicast packets back to itself, while
	it does not loop back broadcasts)

itojun