fix_datacksum
fix_datacksum(&oip->ip_sum, sumd);
fix_datacksum(&tcp->th_sum, sumd);
fix_datacksum(&tcp->th_sum, psumd);
fix_datacksum(&udp->uh_sum, sumd);
fix_datacksum(&udp->uh_sum, psumd);
fix_datacksum(&orgicmp->icmp_cksum, sumd);
fix_datacksum(&tcp->th_sum, sumd);
fix_datacksum(&tcp->th_sum, psumd);
fix_datacksum(&udp->uh_sum, sumd);
fix_datacksum(&udp->uh_sum, psumd);
fix_datacksum(&orgicmp->icmp6_cksum, sumd);
extern void fix_datacksum __P((u_short *, u_32_t));