Simple multicast question

[Frank Kardel <kardel%netbsd.org@localhost>]

Hi!

If I were to
 1) create an IPv4, DGRAM (UDP) socket
 2) bind that to 224.0.1.1
 3) do a IP_ADD_MEMBERSHIP for address 224.0.1.1 and imr_interface = 
INADDR_ANY on that socket
 4) start recvmsg-ing on it

Would I be able to read the packets that I see via tcpdump going to 
224.0.1.1 ?

The thing is I see the packets via tcpdump, IGMP seems to work 
correctly, but nothing arrives in the
program. Am I missing something or do we have a multicast reception 
problem in NetBSD
(even for older versions of -current)?
Short investigation gave that mcast packets can be dropped for the 
mcast-address not being
in the receiving interface's mcast-address-list (ip_input.c) or when the 
dst-addr/port is not found (udp_usrreq.c).

The interface is wm0 and ifconfig shows the multicast counter going up 
as does the CANTFORWARD IP-statistics counter.

Frank