add the locking for coordinating between ioctls and a clone destroy.

i wrote this in mpe before porting and committing it in mpw, but
forgot to commit the mpe version.

1 files changed, 29 insertions, 9 deletions

diff --git a/sys/net/if_mpe.c b/sys/net/if_mpe.c
index e4ebe1665a9..ce1d4301b23 100644
--- a/sys/net/if_mpe.c
+++ b/sys/net/if_mpe.c
@@ -1,4 +1,4 @@
-/* $OpenBSD: if_mpe.c,v 1.84 2019/02/14 03:27:42 dlg Exp $ */
+/* $OpenBSD: if_mpe.c,v 1.85 2019/02/20 00:20:19 dlg Exp $ */
 
 /*
  * Copyright (c) 2008 Pierre-Yves Ritschard <pyr@spootnik.org>
@@ -58,6 +58,9 @@ struct mpe_softc {
 	unsigned int		sc_rdomain;
 	struct ifaddr		sc_ifa;
 	struct sockaddr_mpls	sc_smpls;
+
+	struct rwlock		sc_lock;
+	int			sc_dead;
 };
 
 #define MPE_HDRLEN	sizeof(struct shim_hdr)
@@ -110,6 +113,10 @@ mpe_clone_create(struct if_clone *ifc, int unit)
 	ifp->if_type = IFT_MPLS;
 	ifp->if_hdrlen = MPE_HDRLEN;
 	IFQ_SET_MAXLEN(&ifp->if_snd, IFQ_MAXLEN);
+
+	rw_init(&sc->sc_lock, ifp->if_xname);
+	sc->sc_dead = 0;
+
 	if_attach(ifp);
 	if_alloc_sadl(ifp);
 #if NBPFILTER > 0
@@ -130,11 +137,16 @@ mpe_clone_destroy(struct ifnet *ifp)
 {
 	struct mpe_softc	*sc = ifp->if_softc;
 
+	rw_enter_write(&sc->sc_lock);
+	sc->sc_dead = 1;
+
 	if (sc->sc_smpls.smpls_label) {
 		rt_ifa_del(&sc->sc_ifa, RTF_MPLS|RTF_LOCAL,
 		    smplstosa(&sc->sc_smpls), sc->sc_rdomain);
 	}
 
+	rw_exit_write(&sc->sc_lock);
+
 	if_detach(ifp);
 	free(sc, M_DEVBUF, sizeof *sc);
 	return (0);
@@ -281,6 +293,10 @@ mpe_set_label(struct mpe_softc *sc, uint32_t label, unsigned int rdomain)
 {
 	int error;
 
+	rw_assert_wrlock(&sc->sc_lock);
+	if (sc->sc_dead)
+		return (ENXIO);
+
 	if (sc->sc_smpls.smpls_label) {
 		/* remove old MPLS route */
 		rt_ifa_del(&sc->sc_ifa, RTF_MPLS|RTF_LOCAL,
@@ -337,9 +353,12 @@ mpe_ioctl(struct ifnet *ifp, u_long cmd, caddr_t data)
 			break;
 		}
 		shim.shim_label = MPLS_LABEL2SHIM(shim.shim_label);
-		if (sc->sc_smpls.smpls_label == shim.shim_label)
-			break;
-		error = mpe_set_label(sc, shim.shim_label, sc->sc_rdomain);
+		rw_enter_write(&sc->sc_lock);
+		if (sc->sc_smpls.smpls_label != shim.shim_label) {
+			error = mpe_set_label(sc, shim.shim_label,
+			    sc->sc_rdomain);
+		}
+		rw_exit_write(&sc->sc_lock);
 		break;
 	case SIOCSLIFPHYRTABLE:
 		if (ifr->ifr_rdomainid < 0 ||
@@ -349,11 +368,12 @@ mpe_ioctl(struct ifnet *ifp, u_long cmd, caddr_t data)
 			error = EINVAL;
 			break;
 		}
-		if (sc->sc_rdomain == ifr->ifr_rdomainid)
-			break;
-
-		error = mpe_set_label(sc, sc->sc_smpls.smpls_label,
-		    ifr->ifr_rdomainid);
+		rw_enter_write(&sc->sc_lock);
+		if (sc->sc_rdomain != ifr->ifr_rdomainid) {
+			error = mpe_set_label(sc, sc->sc_smpls.smpls_label,
+			    ifr->ifr_rdomainid);
+		}
+		rw_exit_write(&sc->sc_lock);
 		break;
 	case SIOCGLIFPHYRTABLE:
 		ifr->ifr_rdomainid = sc->sc_rdomain;