IFCAP_TOE6
if ((if_getcapenable(ifp) & IFCAP_TOE6) == 0)
#define IFCAP_TOE (IFCAP_TOE4 | IFCAP_TOE6)
setmask |= mask & (IFCAP_TOE4 | IFCAP_TOE6);
if (nam->sa_family == AF_INET6 && !(ifp->if_capenable & IFCAP_TOE6))
(family == AF_INET6 && !(ifp->if_capenable & IFCAP_TOE6)))