ipf_fix_outcksum
ipf_fix_outcksum(0, &ip->ip_sum, sum2, 0);
ipf_fix_outcksum(0, &fin->fin_ip->ip_sum, msumd, 0);
ipf_fix_outcksum(fin->fin_cksum & FI_CK_L4PART,
ipf_fix_outcksum(0, &ip->ip_sum, sumd, 0);
ipf_fix_outcksum(fin->fin_cksum, csump,
ipf_fix_outcksum(0, &fin->fin_ip->ip_sum, ipsumd, 0);
ipf_fix_outcksum(0, &ip->ip_sum, sumd, 0);
ipf_fix_outcksum(0, csump, nat->nat_sumd[0], 0);
ipf_fix_outcksum(0, csump, sumd, 0);
ipf_fix_outcksum(0, &fin->fin_ip->ip_sum, sumd, 0);
extern void ipf_fix_outcksum(int, u_short *, u_32_t, u_32_t);
ipf_fix_outcksum(fin->fin_cksum, csump,
ipf_fix_outcksum(0, csump, nat->nat_sumd[0], 0);
ipf_fix_outcksum(0, &ip->ip_sum, sd, 0);
ipf_fix_outcksum(0, &tcp->th_sum, is->is_sumd[0], 0);
ipf_fix_outcksum(0, &tcp->th_sum, is->is_sumd[1], 0);