[src/trunk]: src/sys/netinet6 Don't GC an NDP cache that is added just before GC

[ozaki-r <ozaki-r%NetBSD.org@localhost>]

details:   https://anonhg.NetBSD.org/src/rev/d22c2870c9a1
branches:  trunk
changeset: 817687:d22c2870c9a1
user:      ozaki-r <ozaki-r%NetBSD.org@localhost>
date:      Fri Sep 02 07:15:14 2016 +0000

description:
Don't GC an NDP cache that is added just before GC

This fixes unstable test results of ndp_neighborgcthresh.

diffstat:

 sys/netinet6/nd6.c |  28 +++++++++++++++++++---------
 1 files changed, 19 insertions(+), 9 deletions(-)

diffs (95 lines):

diff -r 14884eaf388d -r d22c2870c9a1 sys/netinet6/nd6.c
--- a/sys/netinet6/nd6.c        Fri Sep 02 05:59:04 2016 +0000
+++ b/sys/netinet6/nd6.c        Fri Sep 02 07:15:14 2016 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: nd6.c,v 1.206 2016/08/06 20:00:14 roy Exp $    */
+/*     $NetBSD: nd6.c,v 1.207 2016/09/02 07:15:14 ozaki-r Exp $        */
 /*     $KAME: nd6.c,v 1.279 2002/06/08 11:16:51 itojun Exp $   */
 
 /*
@@ -31,7 +31,7 @@
  */
 
 #include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: nd6.c,v 1.206 2016/08/06 20:00:14 roy Exp $");
+__KERNEL_RCSID(0, "$NetBSD: nd6.c,v 1.207 2016/09/02 07:15:14 ozaki-r Exp $");
 
 #ifdef _KERNEL_OPT
 #include "opt_net_mpsafe.h"
@@ -1300,10 +1300,17 @@
        return;
 }
 
+struct gc_args {
+       int gc_entries;
+       const struct in6_addr *skip_in6;
+};
+
 static int
 nd6_purge_entry(struct lltable *llt, struct llentry *ln, void *farg)
 {
-       int *n = farg;
+       struct gc_args *args = farg;
+       int *n = &args->gc_entries;
+       const struct in6_addr *skip_in6 = args->skip_in6;
 
        if (*n <= 0)
                return 0;
@@ -1311,6 +1318,9 @@
        if (ND6_LLINFO_PERMANENT(ln))
                return 0;
 
+       if (IN6_ARE_ADDR_EQUAL(&ln->r_l3addr.addr6, skip_in6))
+               return 0;
+
        LLE_WLOCK(ln);
        if (ln->ln_state > ND6_LLINFO_INCOMPLETE)
                ln->ln_state = ND6_LLINFO_STALE;
@@ -1324,17 +1334,17 @@
 }
 
 static void
-nd6_gc_neighbors(struct lltable *llt)
+nd6_gc_neighbors(struct lltable *llt, const struct in6_addr *in6)
 {
-       int max_gc_entries = 10;
 
        if (ip6_neighborgcthresh >= 0 &&
            lltable_get_entry_count(llt) >= ip6_neighborgcthresh) {
+               struct gc_args gc_args = {10, in6};
                /*
                 * XXX entries that are "less recently used" should be
                 * freed first.
                 */
-               lltable_foreach_lle(llt, nd6_purge_entry, &max_gc_entries);
+               lltable_foreach_lle(llt, nd6_purge_entry, &gc_args);
        }
 }
 
@@ -1546,7 +1556,7 @@
                 * purging for some entries.
                 */
                if (rt->rt_ifp != NULL)
-                       nd6_gc_neighbors(LLTABLE6(rt->rt_ifp));
+                       nd6_gc_neighbors(LLTABLE6(rt->rt_ifp), NULL);
                break;
            }
 
@@ -2138,7 +2148,7 @@
         * purging for some entries.
         */
        if (is_newentry)
-               nd6_gc_neighbors(LLTABLE6(ifp));
+               nd6_gc_neighbors(LLTABLE6(ifp), &ln->r_l3addr.addr6);
 
        /*
         * When the link-layer address of a router changes, select the
@@ -2381,7 +2391,7 @@
                m_freem(m);
   exit:
        if (created)
-               nd6_gc_neighbors(LLTABLE6(ifp));
+               nd6_gc_neighbors(LLTABLE6(ifp), &dst->sin6_addr);
 
        return error;
 #undef senderr