adj_cksum
adj_cksum(&ipha->ipha_hdr_checksum, adj_ip_sum);
adj_cksum(tp_cksum, adj_tp_sum);
adj_cksum(tp_cksum, adj_tp_sum);
adj_cksum(&ipha->ipha_hdr_checksum, adj_ip_sum);
adj_cksum(tp_cksum, adj_tp_sum);
adj_cksum(tp_cksum, adj_tp_sum);
adj_cksum(&out_iph->ipha_hdr_checksum, sum);