ip6_mfilter_alloc
im6f[0] = ip6_mfilter_alloc(M_WAITOK, 0, 0);
im6f[1] = ip6_mfilter_alloc(M_WAITOK, 0, 0);
imf = ip6_mfilter_alloc(M_NOWAIT, MCAST_UNDEFINED, MCAST_INCLUDE);
imf = ip6_mfilter_alloc(M_NOWAIT, MCAST_UNDEFINED, MCAST_EXCLUDE);
struct in6_mfilter *ip6_mfilter_alloc(int mflags, int st0, int st1);
im6f = ip6_mfilter_alloc(M_WAITOK, 0, 0);