in_osrcaddr
nat->in_osrcaddr &= nat->in_osrcmsk;
n->in_ndstaddr = n->in_osrcaddr;
match = ((fin->fin_saddr & np->in_osrcmsk) != np->in_osrcaddr);
} else if ((ipa & np->in_osrcmsk) != np->in_osrcaddr)
j = (n->in_osrcaddr & n->in_osrcmsk);
ipn->in_osrcaddr = nat->nat_osrcaddr;