Make mpe(4) work again by:

- Change the way mpe figures out the IP of the MPLS nexthop. Instead of using
RTF_GATEWAY and so a valid (and cachable) gateway route just use the
gateway IP address of the route (rt->rt_gateway).
- Make sure the interface is up when adding a mplslabel. The inserted route
is in rtable 0 and so invisible for the link state tracker. Forcing the if_up
ensures that the added route is RTF_UP.
OK mpi@

diff --git a/sys/net/if_mpe.c b/sys/net/if_mpe.c
index 957934b..28cf41e 100644 (file)
--- a/sys/net/if_mpe.c
+++ b/sys/net/if_mpe.c
@@ -1,4 +1,4 @@
-/* $OpenBSD: if_mpe.c,v 1.62 2017/08/14 16:14:02 reyk Exp $ */
+/* $OpenBSD: if_mpe.c,v 1.63 2017/11/29 19:36:03 claudio Exp $ */
 
 /*
  * Copyright (c) 2008 Pierre-Yves Ritschard <pyr@spootnik.org>
@@ -178,7 +178,6 @@ mpestart(struct ifnet *ifp0)
                        rtfree(rt);
                        continue;
                }
-
 #if NBPFILTER > 0
                if (ifp0->if_bpf) {
                        /* remove MPLS label before passing packet to bpf */
@@ -191,7 +190,7 @@ mpestart(struct ifnet *ifp0)
                        m->m_pkthdr.len += sizeof(struct shim_hdr);
                }
 #endif
-               /* XXX lie, but mpls_output will only look at sa_family */
+               /* XXX lie, but mpls_output looks only at sa_family */
                sa->sa_family = AF_MPLS;
 
                mpls_output(ifp, m, sa, rt);
@@ -207,6 +206,7 @@ mpeoutput(struct ifnet *ifp, struct mbuf *m, struct sockaddr *dst,
        struct shim_hdr shim;
        int             error;
        int             off;
+       in_addr_t       addr;
        u_int8_t        op = 0;
 
 #ifdef DIAGNOSTIC
@@ -223,12 +223,15 @@ mpeoutput(struct ifnet *ifp, struct mbuf *m, struct sockaddr *dst,
        error = 0;
        switch (dst->sa_family) {
        case AF_INET:
-               if (rt && rt->rt_flags & RTF_MPLS) {
-                       shim.shim_label =
-                           ((struct rt_mpls *)rt->rt_llinfo)->mpls_label;
-                       shim.shim_label |= MPLS_BOS_MASK;
-                       op =  ((struct rt_mpls *)rt->rt_llinfo)->mpls_operation;
+               if (!rt || !(rt->rt_flags & RTF_MPLS)) {
+                       m_freem(m);
+                       error = ENETUNREACH;
+                       goto out;
                }
+               shim.shim_label =
+                   ((struct rt_mpls *)rt->rt_llinfo)->mpls_label;
+               shim.shim_label |= MPLS_BOS_MASK;
+               op =  ((struct rt_mpls *)rt->rt_llinfo)->mpls_operation;
                if (op != MPLS_OP_PUSH) {
                        m_freem(m);
                        error = ENETUNREACH;
@@ -247,8 +250,9 @@ mpeoutput(struct ifnet *ifp, struct mbuf *m, struct sockaddr *dst,
                        goto out;
                }
                *mtod(m, sa_family_t *) = AF_INET;
+               addr = satosin(rt->rt_gateway)->sin_addr.s_addr;
                m_copyback(m, sizeof(sa_family_t), sizeof(in_addr_t),
-                   (caddr_t)&((satosin(dst)->sin_addr)), M_NOWAIT);
+                   &addr, M_NOWAIT);
                break;
        default:
                m_freem(m);
@@ -320,6 +324,12 @@ mpeioctl(struct ifnet *ifp, u_long cmd, caddr_t data)
                }
                if (error)
                        break;
+               /*
+                * force interface up for now,
+                * linkstate of MPLS route is not tracked
+                */
+               if (!ISSET(ifp->if_flags, IFF_UP))
+                       if_up(ifp);
                ifm = ifp->if_softc;
                if (ifm->sc_smpls.smpls_label) {
                        /* remove old MPLS route */
@@ -337,6 +347,7 @@ mpeioctl(struct ifnet *ifp, u_long cmd, caddr_t data)
                break;
        case SIOCSIFRDOMAIN:
                /* must readd the MPLS "route" for our label */
+               /* XXX does not make sense, the MPLS route is on rtable 0 */
                ifm = ifp->if_softc;
                if (ifr->ifr_rdomainid != ifp->if_rdomain) {
                        if (ifm->sc_smpls.smpls_label) {