restore the previous semantics wrt if up, tunnel, and address config.

our network drivers have a feature where if you configure an address
on the interface, it implicitly brings the interface up. i changed
etherip so you could only change the tunnel configuration while it
down, but maintained the implicit up behaviour. bringing the tunnel
up also relied on having valid configuration, ie, tunnel addreses
must be configured otherwise up will fail.

this means people who have address config in their hostname.etherip
files before config for the tunnel addresses will have problems.
firstly, the address wont be configured because falling through to
the interface up fails because the tunnel isnt configured correctly,
and that error makes the address config roll back. secondly, config
that relies on configuring the address to bring the interface up
will fail because there's no explicit up after the tunnel config.

this diff rolls the tunnel config back to keeping the interface on
a list, and allowing config at any time. the caveat to this is that
it makes mpsafety hard because inconsistent intermediate states are
visible when packets are being processed.

1 files changed, 38 insertions, 33 deletions

diff --git a/sys/net/if_etherip.c b/sys/net/if_etherip.c
index 7a0b4bbd3bb..301dc221d42 100644
--- a/sys/net/if_etherip.c
+++ b/sys/net/if_etherip.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: if_etherip.c,v 1.34 2018/02/12 00:09:39 dlg Exp $	*/
+/*	$OpenBSD: if_etherip.c,v 1.35 2018/02/12 01:43:42 dlg Exp $	*/
 /*
  * Copyright (c) 2015 Kazuya GODA <goda@openbsd.org>
  *
@@ -72,17 +72,15 @@ struct etherip_tunnel {
 	unsigned int	t_rtableid;
 	sa_family_t	t_af;
 
-	RBT_ENTRY(etherip_tunnel)
+	TAILQ_ENTRY(etherip_tunnel)
 			t_entry;
 };
 
-RBT_HEAD(etherip_tree, etherip_tunnel);
+TAILQ_HEAD(etherip_list, etherip_tunnel);
 
 static inline int etherip_cmp(const struct etherip_tunnel *,
     const struct etherip_tunnel *);
 
-RBT_PROTOTYPE(etherip_tree, etherip_tunnel, t_entry, etherip_cmp);
-
 struct etherip_softc {
 	struct etherip_tunnel	sc_tunnel; /* must be first */
 	struct arpcom		sc_ac;
@@ -110,12 +108,13 @@ int etherip_get_tunnel(struct etherip_softc *, struct if_laddrreq *);
 int etherip_del_tunnel(struct etherip_softc *);
 int etherip_up(struct etherip_softc *);
 int etherip_down(struct etherip_softc *);
+struct etherip_softc *etherip_find(const struct etherip_tunnel *);
 int etherip_input(struct etherip_tunnel *, struct mbuf *, int);
 
 struct if_clone	etherip_cloner = IF_CLONE_INITIALIZER("etherip",
     etherip_clone_create, etherip_clone_destroy);
 
-struct etherip_tree etherip_tree = RBT_INITIALIZER();
+struct etherip_list etherip_list = TAILQ_HEAD_INITIALIZER(etherip_list);
 
 void
 etheripattach(int count)
@@ -155,6 +154,10 @@ etherip_clone_create(struct if_clone *ifc, int unit)
 	if_attach(ifp);
 	ether_ifattach(ifp);
 
+	NET_LOCK();
+	TAILQ_INSERT_TAIL(&etherip_list, &sc->sc_tunnel, t_entry);
+	NET_UNLOCK();
+
 	return (0);
 }
 
@@ -166,6 +169,8 @@ etherip_clone_destroy(struct ifnet *ifp)
 	NET_LOCK();
 	if (ISSET(ifp->if_flags, IFF_RUNNING))
 		etherip_down(sc);
+
+	TAILQ_REMOVE(&etherip_list, &sc->sc_tunnel, t_entry);
 	NET_UNLOCK();
 
 	ifmedia_delete_instance(&sc->sc_media, IFM_INST_ANY);
@@ -217,7 +222,9 @@ etherip_start(struct ifnet *ifp)
 			break;
 #endif
 		default:
-			unhandled_af(sc->sc_tunnel.t_af);
+			/* unhandled_af(sc->sc_tunnel.t_af); */
+			m_freem(m);
+			continue;
 		}
 
 		if (error)
@@ -250,10 +257,6 @@ etherip_ioctl(struct ifnet *ifp, u_long cmd, caddr_t data)
 		break;
 
 	case SIOCSLIFPHYRTABLE:
-		if (ISSET(ifp->if_flags, IFF_RUNNING)) {
-			error = EBUSY;
-			break;
-		}
 		if (ifr->ifr_rdomainid < 0 ||
 		    ifr->ifr_rdomainid > RT_TABLEID_MAX ||
 		    !rtable_exists(ifr->ifr_rdomainid)) {
@@ -268,21 +271,12 @@ etherip_ioctl(struct ifnet *ifp, u_long cmd, caddr_t data)
 		break;
 
 	case SIOCSLIFPHYADDR:
-		if (ISSET(ifp->if_flags, IFF_RUNNING)) {
-			error = EBUSY;
-			break;
-		}
-
 		error = etherip_set_tunnel(sc, (struct if_laddrreq *)data);
 		break;
 	case SIOCGLIFPHYADDR:
 		error = etherip_get_tunnel(sc, (struct if_laddrreq *)data);
 		break;
 	case SIOCDIFPHYADDR:
-		if (ISSET(ifp->if_flags, IFF_RUNNING)) {
-			error = EBUSY;
-			break;
-		}
 		error = etherip_del_tunnel(sc);
 		break;
 
@@ -443,14 +437,11 @@ etherip_del_tunnel(struct etherip_softc *sc)
 int
 etherip_up(struct etherip_softc *sc)
 {
-	if (sc->sc_tunnel.t_af == AF_UNSPEC)
-		return (ENXIO);
+	struct ifnet *ifp = &sc->sc_ac.ac_if;
 
 	NET_ASSERT_LOCKED();
-	if (RBT_INSERT(etherip_tree, &etherip_tree, &sc->sc_tunnel) != NULL)
-		return (EADDRINUSE);
 
-	SET(sc->sc_ac.ac_if.if_flags, IFF_RUNNING);
+	SET(ifp->if_flags, IFF_RUNNING);
 
 	return (0);
 }
@@ -459,14 +450,11 @@ int
 etherip_down(struct etherip_softc *sc)
 {
 	struct ifnet *ifp = &sc->sc_ac.ac_if;
-	NET_ASSERT_LOCKED();
 
-	RBT_REMOVE(etherip_tree, &etherip_tree, &sc->sc_tunnel);
+	NET_ASSERT_LOCKED();
 
 	CLR(ifp->if_flags, IFF_RUNNING);
 
-	ifq_barrier(&ifp->if_snd);
-
 	return (0);
 }
 
@@ -531,6 +519,26 @@ ip_etherip_input(struct mbuf **mp, int *offp, int type, int af)
 	return (etherip_input(&key, m, *offp));
 }
 
+struct etherip_softc *
+etherip_find(const struct etherip_tunnel *key)
+{
+	struct etherip_tunnel *t;
+	struct etherip_softc *sc;
+
+	TAILQ_FOREACH(t, &etherip_list, t_entry) {
+		if (etherip_cmp(key, t) != 0)
+			continue;
+
+		sc = (struct etherip_softc *)t;
+		if (!ISSET(sc->sc_ac.ac_if.if_flags, IFF_RUNNING))
+			continue;
+
+		return (sc);
+	}
+
+	return (NULL);
+}
+
 int
 etherip_input(struct etherip_tunnel *key, struct mbuf *m, int hlen)
 {
@@ -547,8 +555,7 @@ etherip_input(struct etherip_tunnel *key, struct mbuf *m, int hlen)
 	key->t_rtableid = m->m_pkthdr.ph_rtableid;
 
 	NET_ASSERT_LOCKED();
-	sc = (struct etherip_softc *)RBT_FIND(etherip_tree,
-	    &etherip_tree, key);
+	sc = etherip_find(key);
 	if (sc == NULL) {
 		etheripstat_inc(etherips_noifdrops);
 		goto drop;
@@ -747,5 +754,3 @@ etherip_cmp(const struct etherip_tunnel *a, const struct etherip_tunnel *b)
 
 	return (0);
 }
-
-RBT_GENERATE(etherip_tree, etherip_tunnel, t_entry, etherip_cmp);