To make ND6 mp-safe, the life time of struct llinfo_nd6 *ln =

rt->rt_llinfo has to be guaranteed.  Replace the complicated logic
in nd6_rtrequest() case RTM_ADD with what we have in ARP.  This
avoids accessing ln here.
Digging through histroy shows a lot of refactoring that makes
rt_expire handling in RTM_ADD obsolete.  Just initialize it to 0.
Cloning and local routes should never expire.  If RTF_LLINFO is
set, ln should not be NULL.  So nd6_llinfo_settimer() was not reached
in this case.
While there, remove obsolete comments and #if 0 code that never
worked.
OK kn@ claudio@

diff --git a/sys/netinet6/nd6.c b/sys/netinet6/nd6.c
index 491e66f..ea91d42 100644 (file)
--- a/sys/netinet6/nd6.c
+++ b/sys/netinet6/nd6.c
@@ -1,4 +1,4 @@
-/*     $OpenBSD: nd6.c,v 1.277 2023/05/08 11:47:52 bluhm Exp $ */
+/*     $OpenBSD: nd6.c,v 1.278 2023/05/08 13:14:21 bluhm Exp $ */
 /*     $KAME: nd6.c,v 1.280 2002/06/08 19:52:07 itojun Exp $   */
 
 /*
@@ -780,40 +780,12 @@ nd6_rtrequest(struct ifnet *ifp, int req, struct rtentry *rt)
 
        switch (req) {
        case RTM_ADD:
-               if ((rt->rt_flags & RTF_CLONING) ||
-                   ((rt->rt_flags & (RTF_LLINFO | RTF_LOCAL)) && ln == NULL)) {
-                       if (ln != NULL)
-                               nd6_llinfo_settimer(ln, 0);
-                       if ((rt->rt_flags & RTF_CLONING) != 0)
-                               break;
+               if (rt->rt_flags & RTF_CLONING) {
+                       rt->rt_expire = 0;
+                       break;
                }
-               /*
-                * In IPv4 code, we try to announce new RTF_ANNOUNCE entry here.
-                * We don't do that here since llinfo is not ready yet.
-                *
-                * There are also couple of other things to be discussed:
-                * - unsolicited NA code needs improvement beforehand
-                * - RFC2461 says we MAY send multicast unsolicited NA
-                *   (7.2.6 paragraph 4), however, it also says that we
-                *   SHOULD provide a mechanism to prevent multicast NA storm.
-                *   we don't have anything like it right now.
-                *   note that the mechanism needs a mutual agreement
-                *   between proxies, which means that we need to implement
-                *   a new protocol, or a new kludge.
-                * - from RFC2461 6.2.4, host MUST NOT send an unsolicited NA.
-                *   we need to check ip6forwarding before sending it.
-                *   (or should we allow proxy ND configuration only for
-                *   routers?  there's no mention about proxy ND from hosts)
-                */
-#if 0
-               /* XXX it does not work */
-               if (rt->rt_flags & RTF_ANNOUNCE)
-                       nd6_na_output(ifp,
-                             &satosin6(rt_key(rt))->sin6_addr,
-                             &satosin6(rt_key(rt))->sin6_addr,
-                             ip6_forwarding ? ND_NA_FLAG_ROUTER : 0,
-                             1, NULL);
-#endif
+               if ((rt->rt_flags & RTF_LOCAL) && rt->rt_llinfo == NULL)
+                       rt->rt_expire = 0;
                /* FALLTHROUGH */
        case RTM_RESOLVE:
                if (gate->sa_family != AF_LINK ||