icmp6_seq
icp->icmp6_seq = htons(seq);
seq = ntohs(icp->icmp6_seq);
hv += oic->icmp6_seq;
(oic->icmp6_seq == ic->ici_seq) &&
hv += oic->icmp6_seq;
icp->icmp6_seq = htons(seq);
icmp->icmp6_seq == htons(seq))
icp->icmp6_seq == htons(seq))