MF6CHASH
hash = MF6CHASH(ip6->ip6_src, ip6->ip6_dst);
struct mf6c *_rt = mf6ctable[MF6CHASH(o,g)]; \
hash = MF6CHASH(mfccp->mf6cc_origin.sin6_addr,
hash = MF6CHASH(origin.sin6_addr, mcastgrp.sin6_addr);