_in6_cksum:_inet6_cksum _mbuf_data _mbuf_inet6_cksum _mbuf_len _mbuf_next _mbuf_nextpkt _mbuf_pkthdr_header _mbuf_pkthdr_len _mbuf_pkthdr_rcvif _mbuf_pkthdr_setheader _mbuf_setlen _mbuf_setnextpkt _mbuf_type _nd6_lookup_ipv6