ip_select_route_v4
ire = ip_select_route_v4(firsthop, *src_addrp, ixa,
ire = ip_select_route_v4(firsthop, ipha->ipha_src, ixa, NULL,
extern ire_t *ip_select_route_v4(ipaddr_t, ipaddr_t, ip_xmit_attr_t *,