[src/trunk]: src/sys/netinet6 Userland really has no business with NA messages.

[roy <roy%NetBSD.org@localhost>]

details:   https://anonhg.NetBSD.org/src/rev/bf44db62babe
branches:  trunk
changeset: 459182:bf44db62babe
user:      roy <roy%NetBSD.org@localhost>
date:      Thu Aug 29 16:26:43 2019 +0000

description:
Userland really has no business with NA messages.
However, RFC 4861 6.2.5 only says departing routers
*SHOULD* send RA with lifetime of zero and *MUST*
send all subsequent NA messages if the router flag
unset.

To help userland avoid the expensive process of
parsing NA messages, send RTM_CHANGE without a
lladdr in the gateway.
This is different from the intial RTM_ADD also
without a lladdr in the gateway and RTM_DELETE.

diffstat:

 sys/netinet6/nd6_nbr.c |  30 ++++++++++++++++++++++++------
 1 files changed, 24 insertions(+), 6 deletions(-)

diffs (60 lines):

diff -r b1098aadd0bb -r bf44db62babe sys/netinet6/nd6_nbr.c
--- a/sys/netinet6/nd6_nbr.c    Thu Aug 29 16:20:48 2019 +0000
+++ b/sys/netinet6/nd6_nbr.c    Thu Aug 29 16:26:43 2019 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: nd6_nbr.c,v 1.169 2019/08/29 14:28:06 roy Exp $        */
+/*     $NetBSD: nd6_nbr.c,v 1.170 2019/08/29 16:26:43 roy Exp $        */
 /*     $KAME: nd6_nbr.c,v 1.61 2001/02/10 16:06:14 jinmei Exp $        */
 
 /*
@@ -31,7 +31,7 @@
  */
 
 #include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: nd6_nbr.c,v 1.169 2019/08/29 14:28:06 roy Exp $");
+__KERNEL_RCSID(0, "$NetBSD: nd6_nbr.c,v 1.170 2019/08/29 16:26:43 roy Exp $");
 
 #ifdef _KERNEL_OPT
 #include "opt_inet.h"
@@ -854,10 +854,27 @@
                         * Remove the sender from the Default Router List and
                         * update the Destination Cache entries.
                         */
+                       const struct in6_addr *in6 = &ln->r_l3addr.addr6;
                        struct nd_defrouter *dr;
-                       const struct in6_addr *in6;
+                       struct sockaddr_in6 sin6;
 
-                       in6 = &ln->r_l3addr.addr6;
+                       /*
+                        * Userland really has no business with NA messages.
+                        * However, RFC 4861 6.2.5 only says departing routers
+                        * *SHOULD* send RA with lifetime of zero and *MUST*
+                        * send all subsequent NA messages if the router flag
+                        * unset.
+                        *
+                        * To help userland avoid the expensive process of
+                        * parsing NA messages, send RTM_CHANGE without a
+                        * lladdr in the gateway.
+                        * This is different from the intial RTM_ADD also
+                        * without a lladdr in the gateway and RTM_DELETE.
+                        */
+                       sockaddr_in6_init(&sin6, in6, 0, 0, 0);
+                       rt_clonedmsg(RTM_CHANGE, sin6tosa(&sin6), NULL,
+                           ln->lle_tbl->llt_ifp);
+                       rt_announce = true;
 
                        ND6_WLOCK();
                        dr = nd6_defrouter_lookup(in6, ln->lle_tbl->llt_ifp);
@@ -887,8 +904,9 @@
        if (rt_announce) {
                struct sockaddr_in6 sin6;
 
-               sockaddr_in6_init(&sin6, &taddr6, 0, 0, 0);
-               rt_clonedmsg(RTM_CHANGE, sin6tosa(&sin6), lladdr, ifp);
+               sockaddr_in6_init(&sin6, &ln->r_l3addr.addr6, 0, 0, 0);
+               rt_clonedmsg(RTM_CHANGE, sin6tosa(&sin6),
+                   (char *)&ln->ll_addr, ln->lle_tbl->llt_ifp);
        }
 
  freeit: