This is an old revision of the document!
Adapt to your needs:
iptables -A INPUT -i eth0 -m pkttype --pkt-type multicast -j ACCEPT iptables -A INPUT -i eth0 -m pkttype --pkt-type broadcast -j ACCEPT
Some sources: https://serverfault.com/questions/325652/how-to-make-iptables-allow-rule-for-multicast