if_setrdomain: allow empty rtables to be turned into rdomains, not just

nonexistant ones as before. nasty error handling with bluhm, feedback mpi as
well. ok bluhm

diff --git a/sys/net/if.c b/sys/net/if.c
index a78b53d..0a6c415 100644 (file)
--- a/sys/net/if.c
+++ b/sys/net/if.c
@@ -1,4 +1,4 @@
-/*     $OpenBSD: if.c,v 1.560 2018/09/08 01:03:59 yasuoka Exp $        */
+/*     $OpenBSD: if.c,v 1.561 2018/09/09 10:09:06 henning Exp $        */
 /*     $NetBSD: if.c,v 1.35 1996/05/07 05:26:04 thorpej Exp $  */
 
 /*
@@ -1738,7 +1738,7 @@ int
 if_setrdomain(struct ifnet *ifp, int rdomain)
 {
        struct ifreq ifr;
-       int error, up = 0, s;
+       int error, createerr, up = 0, s;
 
        if (rdomain < 0 || rdomain > RT_TABLEID_MAX)
                return (EINVAL);
@@ -1752,28 +1752,29 @@ if_setrdomain(struct ifnet *ifp, int rdomain)
         * Create the routing table if it does not exist, including its
         * loopback interface with unit == rdomain.
         */
-       if (!rtable_exists(rdomain)) {
+       if (!rtable_exists(rdomain) || rtable_empty(rdomain)) {
                struct ifnet *loifp;
                char loifname[IFNAMSIZ];
                unsigned int unit = rdomain;
 
                snprintf(loifname, sizeof(loifname), "lo%u", unit);
-               error = if_clone_create(loifname, 0);
+               createerr = if_clone_create(loifname, 0);
+               if (createerr && createerr != EEXIST)
+                       return (createerr);
 
                if ((loifp = ifunit(loifname)) == NULL)
                        return (ENXIO);
 
-               /* Do not error out if creating the default lo(4) interface */
-               if (error && (ifp != loifp || error != EEXIST))
-                       return (error);
-
-               if ((error = rtable_add(rdomain)) == 0)
-                       rtable_l2set(rdomain, rdomain, loifp->if_index);
-               if (error) {
-                       if_clone_destroy(loifname);
-                       return (error);
+               if (!rtable_exists(rdomain)) {
+                       error = rtable_add(rdomain);
+                       if (error) {
+                               if (createerr != EEXIST)
+                                       if_clone_destroy(loifname);
+                               return (error);
+                       }
                }
 
+               rtable_l2set(rdomain, rdomain, loifp->if_index);
                loifp->if_rdomain = rdomain;
        }