ifa_ifwithnet
struct ifaddr *ifa_ifwithnet(const struct sockaddr *, int, int);
ifa = ifa_ifwithnet(gateway, 0, fibnum);
ifa = ifa_ifwithnet(info->rti_info[RTAX_DST], 1,
ia = ifatoia(ifa_ifwithnet((struct sockaddr *)sin, 0,
ia = ifatoia(ifa_ifwithnet(sintosa(&dst), 0,
if ((ifa = ifa_ifwithnet((struct sockaddr *)gateway, 0, fibnum))==NULL)
ia = (INA)ifa_ifwithnet((SA)&ipaddr, 0,
(ia = ifatoia(ifa_ifwithnet(sintosa(dst), 0,