in_cksum_skip
csum = in_cksum_skip(m, ntohs(ip->ip_len) + offset -
if (in_cksum_skip(m, len, iphlen)) {
ch_ptr->carp_cksum = in_cksum_skip(m, len, sizeof(*ip));
ch_ptr->carp_cksum = in_cksum_skip(m, len, sizeof(*ip6));
if (in_cksum_skip(m, hlen + icmplen, hlen)) {
csum = in_cksum_skip(m, ntohs(ip->ip_len), offset);