Hi kcedisonguru ;
Have you check this code [Linux/net/ipv4/igmp.c - Linux Cross Reference - Free Electrons]?
Are you building a new image or are you working with the latest Release?
There are some links trying to work with an IGMP on Linux, we could start with that.
CMata - Thanks for the information.
I was able to accomplish what I needed by using the iperf command followed by tcpdump. The exact command line was:
iperf -s -u -B MULTICAST_ADDRESS