It was possible to create a gateway route pointing to another gateway

route by changing the gateway.  Despite the error message when doing
so, the route did actually change.  The gateway is modified by
rt_setgate(), the error is created by rt_getifa().  Do these
operations the other way around.
OK mpi@

diff --git a/sys/net/rtsock.c b/sys/net/rtsock.c
index 12d963e..8c81e1b 100644 (file)
--- a/sys/net/rtsock.c
+++ b/sys/net/rtsock.c
@@ -1,4 +1,4 @@
-/*     $OpenBSD: rtsock.c,v 1.174 2015/10/23 10:22:29 claudio Exp $    */
+/*     $OpenBSD: rtsock.c,v 1.175 2015/10/23 13:41:41 bluhm Exp $      */
 /*     $NetBSD: rtsock.c,v 1.18 1996/03/29 00:32:10 cgd Exp $  */
 
 /*
@@ -747,14 +747,11 @@ report:
                                    info.rti_info[RTAX_GATEWAY]->sa_len)) {
                                        newgate = 1;
                                }
-                       if (info.rti_info[RTAX_GATEWAY] != NULL &&
-                           (error = rt_setgate(rt, info.rti_info[RTAX_GATEWAY],
-                            tableid)))
-                               goto flush;
                        /*
-                        * new gateway could require new ifaddr, ifp;
+                        * Check reachable gateway before changing the route.
+                        * New gateway could require new ifaddr, ifp;
                         * flags may also be different; ifp may be specified
-                        * by ll sockaddr when protocol address is ambiguous
+                        * by ll sockaddr when protocol address is ambiguous.
                         */
                        if (newgate || info.rti_info[RTAX_IFP] != NULL ||
                            info.rti_info[RTAX_IFA] != NULL) {
@@ -762,6 +759,10 @@ report:
                                        goto flush;
                                ifa = info.rti_ifa;
                        }
+                       if (info.rti_info[RTAX_GATEWAY] != NULL &&
+                           (error = rt_setgate(rt, info.rti_info[RTAX_GATEWAY],
+                            tableid)))
+                               goto flush;
                        if (ifa) {
                                if (rt->rt_ifa != ifa) {
                                        if (rt->rt_ifa->ifa_rtrequest)