OK, well, I enabled pim, robert bradley killed more traps, and I bumped the
clock rate up,
so we basically now have the same kernel config that 3.3.8 had.

As well as had polipo try TFO by default, and update uftp to 3.7.1, and
tried to
config dhcpv6 appropriately for dhcpv6, and twiddle some firewall rules.

And booted it up only to see no /proc/whatever/net/igmp file once again,
and no 224.x.x.x in ip maddr...

It turned out the igmp entries in /proc ARE being  stripped out by a
openwrt patch... which I killed... so I built it again....

and walla! ip maddr shows multicast stuff and the igmp file exists.

Hopefully this will resolve the dlna issue and others.

Get it at:

http://snapon.lab.bufferbloat.net/~cero2/cerowrt/wndr/3.7.2-4/

BTW:

I had a little fun with uftp and uftpd with this (which are capable
of thoroughly exercising multicast and igmp)

http://www.tcnj.edu/~bush/uftp.html

Basically setting up a uftpd client on a couple of machines and
initiating uftp from the router, or vice versa, I was able to transfer
multiple files around at the same time to multiple machines
over wifi and wired.

I've long yearned to have time to truly benchmark multicast
at scale, and that's why uftp has been in there so long...

To setup uftpd on cero (the file receiving deamon)

uftpd -I se00,sw00,sw10,gw00,gw10 -D /tmp # or somewhere

To send a file from somewhere to a listening uftpd

uftp -I the_interface thefile

tons of options, and it's kind of inobvious that sending files
requires an interface to send on, and that the mesh interfaces
won't multicast...

happy multicasting. Have fun with high rates over wifi,
in particular....

-- 
Dave Täht

Fixing bufferbloat with cerowrt:
http://www.teklibre.com/cerowrt/subscribe.html