fix KAME hack in bgpd sa2addr()

[Claudio Jeker]

Copy the version of the __KAME__ hack from route/show.c and more
importantly copy the address after modifying the sa.

This only affects IPv6 link local addresses which are not really used by
bgpd. Still happy if a few more people can give this a spin.
-- 
:wq Claudio

? obj
Index: util.c
===================================================================
RCS file: /cvs/src/usr.sbin/bgpd/util.c,v
retrieving revision 1.64
diff -u -p -r1.64 util.c
--- util.c      16 Jun 2022 15:33:05 -0000      1.64
+++ util.c      16 Jun 2022 15:46:09 -0000
@@ -897,24 +897,24 @@ sa2addr(struct sockaddr *sa, struct bgpd
                break;
        case AF_INET6:
                addr->aid = AID_INET6;
-               memcpy(&addr->v6, &sa_in6->sin6_addr, sizeof(addr->v6));
 #ifdef __KAME__
                /*
                 * XXX thanks, KAME, for this ugliness...
                 * adopted from route/show.c
                 */
-               if (IN6_IS_ADDR_LINKLOCAL(&sa_in6->sin6_addr) ||
-                   IN6_IS_ADDR_MC_LINKLOCAL(&sa_in6->sin6_addr)) {
+               if ((IN6_IS_ADDR_LINKLOCAL(&sa_in6->sin6_addr) ||
+                   IN6_IS_ADDR_MC_LINKLOCAL(&sa_in6->sin6_addr) ||
+                   IN6_IS_ADDR_MC_INTFACELOCAL(&sa_in6->sin6_addr)) &&
+                   sa_in6->sin6_scope_id == 0) {
                        uint16_t tmp16;
                        memcpy(&tmp16, &sa_in6->sin6_addr.s6_addr[2],
                            sizeof(tmp16));
-                       if (tmp16 != 0) {
-                               sa_in6->sin6_scope_id = ntohs(tmp16);
-                               sa_in6->sin6_addr.s6_addr[2] = 0;
-                               sa_in6->sin6_addr.s6_addr[3] = 0;
-                       }
+                       sa_in6->sin6_scope_id = ntohs(tmp16);
+                       sa_in6->sin6_addr.s6_addr[2] = 0;
+                       sa_in6->sin6_addr.s6_addr[3] = 0;
                }
 #endif
+               memcpy(&addr->v6, &sa_in6->sin6_addr, sizeof(addr->v6));
                addr->scope_id = sa_in6->sin6_scope_id; /* I hate v6 */
                if (port)
                        *port = ntohs(sa_in6->sin6_port);