If intra area prefixes move from one router to another router, cloning routes

may become gateway routes and contrary. The kernel does not allow to change the
flags RTF_GATEWAY / RTF_CLONING in RTM_CHANGE messages, but ospf6d tried this
anyway. The result is a broken route.
Instead of modifying such routes remove the old route and insert a new one.

Thanks to Raimund Specht for reporting the problem and testing the fix.

OK claudio@

diff --git a/usr.sbin/ospf6d/kroute.c b/usr.sbin/ospf6d/kroute.c
index 833ef98..5e485ff 100644 (file)
--- a/usr.sbin/ospf6d/kroute.c
+++ b/usr.sbin/ospf6d/kroute.c
@@ -1,4 +1,4 @@
-/*     $OpenBSD: kroute.c,v 1.55 2018/07/10 10:55:21 friehm Exp $ */
+/*     $OpenBSD: kroute.c,v 1.56 2018/07/10 12:17:38 friehm Exp $ */
 
 /*
  * Copyright (c) 2004 Esben Norby <norby@openbsd.org>
@@ -241,9 +241,28 @@ kr_change(struct kroute *kroute, int krcount)
        kroute->rtlabel = rtlabel_tag2id(kroute->ext_tag);
 
        kr = kroute_find(&kroute->prefix, kroute->prefixlen, RTP_OSPF);
-       if (kr != NULL && kr->next == NULL && krcount == 1)
-               /* single path OSPF route */
-               action = RTM_CHANGE;
+       if (kr != NULL && kr->next == NULL && krcount == 1) {
+               /*
+                * single path OSPF route.
+                * The kernel does not allow to change a gateway route to a
+                * cloning route or contrary. In this case remove and add the
+                * route, otherwise change the existing one.
+                */
+               if ((IN6_IS_ADDR_UNSPECIFIED(&kroute->nexthop) &&
+                   !IN6_IS_ADDR_UNSPECIFIED(&kr->r.nexthop)) ||
+                   (!IN6_IS_ADDR_UNSPECIFIED(&kroute->nexthop) &&
+                   IN6_IS_ADDR_UNSPECIFIED(&kr->r.nexthop))) {
+                       if (kr_delete_fib(kr) == 0)
+                               kr = NULL;
+                       else {
+                               log_warn("kr_change: failed to remove route: "
+                                   "%s/%d", log_in6addr(&kr->r.prefix),
+                                   kr->r.prefixlen);
+                               return (-1);
+                       }
+               } else
+                       action = RTM_CHANGE;
+       }
 
        return (kr_change_fib(kr, kroute, krcount, action));
 }