Index: if_etherip.c
===================================================================
RCS file: /cvs/src/sys/net/if_etherip.c,v
retrieving revision 1.45
diff -u -p -r1.45 if_etherip.c
--- if_etherip.c	23 Apr 2019 10:53:45 -0000	1.45
+++ if_etherip.c	16 Jul 2019 09:50:34 -0000
@@ -90,6 +90,10 @@ struct etherip_softc {
 	int			sc_rxhprio;
 	uint16_t		sc_df;
 	uint8_t			sc_ttl;
+
+	unsigned int		sc_parent;
+	void			*sc_lcookie;
+	void			*sc_dcookie;
 };
 
 /*
@@ -115,6 +119,12 @@ int etherip_down(struct etherip_softc *)
 struct etherip_softc *etherip_find(const struct etherip_tunnel *);
 int etherip_input(struct etherip_tunnel *, struct mbuf *, uint8_t, int);
 
+static int	etherip_get_parent(struct etherip_softc *, struct if_parent *);
+static int	etherip_set_parent(struct etherip_softc *,
+		    const struct if_parent *);
+static void	etherip_del_parent(void *);
+static void	etherip_parent_link(void *);
+
 struct if_clone	etherip_cloner = IF_CLONE_INITIALIZER("etherip",
     etherip_clone_create, etherip_clone_destroy);
 
@@ -176,6 +186,8 @@ etherip_clone_destroy(struct ifnet *ifp)
 	struct etherip_softc *sc = ifp->if_softc;
 
 	NET_LOCK();
+	etherip_del_parent(sc);
+
 	if (ISSET(ifp->if_flags, IFF_RUNNING))
 		etherip_down(sc);
 
@@ -214,6 +226,11 @@ etherip_start(struct ifnet *ifp)
 	caddr_t if_bpf;
 #endif
 
+	if (ifp->if_link_state == LINK_STATE_DOWN) {
+		ifq_purge(&ifp->if_snd);
+		return;
+	}
+
 	while ((m = ifq_dequeue(&ifp->if_snd)) != NULL) {
 #if NBPFILTER > 0
 		if_bpf = ifp->if_bpf;
@@ -341,6 +358,19 @@ etherip_ioctl(struct ifnet *ifp, u_long 
 	case SIOCDELMULTI:
 		break;
 
+	case SIOCGIFPARENT:
+		error = etherip_get_parent(sc, (struct if_parent *)data);
+		break;
+
+	case SIOCSIFPARENT:
+		error = etherip_set_parent(sc, (struct if_parent *)data);
+		break;
+
+	case SIOCDIFPARENT:
+		etherip_del_parent(sc);
+		error = 0;
+		break;
+
 	default:
 		error = ether_ioctl(ifp, &sc->sc_ac, cmd, data);
 		break;
@@ -352,6 +382,98 @@ etherip_ioctl(struct ifnet *ifp, u_long 
 	}
 
 	return (error);
+}
+
+static int
+etherip_get_parent(struct etherip_softc *sc, struct if_parent *parent)
+{
+	struct ifnet *ifp0;
+
+	ifp0 = if_get(sc->sc_parent);
+	if (ifp0 == NULL)
+		return (ENOTTY); /* invisible to ifconfig until set */
+
+	if (strlcpy(parent->ifp_parent, ifp0->if_xname,
+	    sizeof(parent->ifp_parent)) > sizeof(parent->ifp_parent))
+		return (EINVAL); /* XXX */
+
+	if_put(ifp0);
+
+	return (0);
+}
+
+static void
+etherip_parent_link(void *arg)
+{
+	struct etherip_softc *sc = arg;
+	struct ifnet *ifp = &sc->sc_ac.ac_if;
+	struct ifnet *ifp0;
+	u_char link_state = LINK_STATE_UNKNOWN;
+
+	ifp0 = if_get(sc->sc_parent);
+	if (ifp0 != NULL) {
+		link_state = (ISSET(ifp0->if_flags, IFF_RUNNING) &&
+		    LINK_STATE_IS_UP(ifp0->if_link_state)) ?
+		    LINK_STATE_FULL_DUPLEX : LINK_STATE_DOWN;
+	}
+	if_put(ifp0);
+
+	if (ifp->if_link_state != link_state) {
+		ifp->if_link_state = link_state;
+		if_link_state_change(ifp);
+	}
+}
+
+static int
+etherip_set_parent(struct etherip_softc *sc, const struct if_parent *parent)
+{
+	struct ifnet *ifp0;
+
+	NET_ASSERT_LOCKED();
+
+	ifp0 = ifunit(parent->ifp_parent); /* no ref */
+	if (ifp0 == NULL)
+		return (EINVAL);
+
+	if (sc->sc_parent == ifp0->if_index)
+		return (0); /* nop */
+
+	sc->sc_parent = ifp0->if_index;
+
+	sc->sc_lcookie = hook_establish(ifp0->if_linkstatehooks, 1,
+	    etherip_parent_link, sc);
+
+	sc->sc_dcookie = hook_establish(ifp0->if_detachhooks, 0,
+	   etherip_del_parent, sc);
+
+	etherip_parent_link(sc);
+
+	return (0);
+}
+
+static void
+etherip_del_parent(void *arg)
+{
+	struct etherip_softc *sc = arg;
+	struct ifnet *ifp = &sc->sc_ac.ac_if;
+	struct ifnet *ifp0;
+	u_char link_state = LINK_STATE_UNKNOWN;
+
+	NET_ASSERT_LOCKED();
+
+	ifp0 = if_get(sc->sc_parent);
+	if (ifp0 != NULL) {
+                hook_disestablish(ifp0->if_detachhooks, sc->sc_dcookie);
+                hook_disestablish(ifp0->if_linkstatehooks, sc->sc_lcookie);
+	}
+	if_put(ifp0);
+
+	sc->sc_parent = 0;
+
+	if (ifp->if_link_state != link_state) {
+		ifp->if_link_state = link_state;
+		if_link_state_change(ifp);
+	}
 }
 
 int