if_addrlist
if (ifp->if_addrlist.tqh_first != NULL)
if (ifp->if_addrlist != NULL)
ifp->if_addrlist.tqh_first = ifa;
ifp->if_addrlist = ifa;
TAILQ_INIT(&ifp->if_addrlist);
ifa = ifp->if_addrlist.tqh_first;
ifa = ifp->if_addrlist;
STAILQ_HEAD(, ifaddr) if_addrlist;