On 19/02/14(Wed) 12:53, Martin Pieuchot wrote:
> Generally, when a NA is received we check if the receiving interface
> has the target address advertised and if it's the case we warn about
> duplicate addresses and bail.
>
> But in the case of a carp interface in BACKUP state it's different. In
> this case we have a hack that sets the ifa to NULL and continue. This
> hack relies on the fact that no cache entry will be found later on
> (because it was removed when the state switch to BACKUP) or that there
> is no lladdr change in the NA (like it is right now) to work properly.
>
> So instead of expecting such things, simply ignore NAs with matching
> address on carp BACKUP nodes since they are more likely to come from
> the carp MASTER.
>
> Less is more, ok?
Anybody?
>
> Index: nd6_nbr.c
> ===================================================================
> RCS file: /home/ncvs/src/sys/netinet6/nd6_nbr.c,v
> retrieving revision 1.75
> diff -u -p -r1.75 nd6_nbr.c
> --- nd6_nbr.c 24 Jan 2014 12:20:22 -0000 1.75
> +++ nd6_nbr.c 13 Feb 2014 11:14:04 -0000
> @@ -570,9 +570,6 @@ nd6_na_input(struct mbuf *m, int off, in
> struct rtentry *rt;
> struct sockaddr_dl *sdl;
> union nd_opts ndopts;
> -#if NCARP > 0
> - struct sockaddr_dl *proxydl = NULL;
> -#endif
> char addr[INET6_ADDRSTRLEN], addr0[INET6_ADDRSTRLEN];
>
> if (ip6->ip6_hlim != 255) {
> @@ -632,11 +629,6 @@ nd6_na_input(struct mbuf *m, int off, in
> }
>
> ifa = &in6ifa_ifpwithaddr(ifp, &taddr6)->ia_ifa;
> -#if NCARP > 0
> - if (ifp->if_type == IFT_CARP && ifa &&
> - !carp_iamatch6(ifp, lladdr, &proxydl))
> - ifa = NULL;
> -#endif
>
> /*
> * Target address matches one of my interface address.
> @@ -652,8 +644,18 @@ nd6_na_input(struct mbuf *m, int off, in
> goto freeit;
> }
>
> - /* Just for safety, maybe unnecessary. */
> if (ifa) {
> +#if NCARP > 0
> + struct sockaddr_dl *proxydl = NULL;
> +
> + /*
> + * Ignore NAs silently for carp addresses if we're not
> + * the CARP master.
> + */
> + if (ifp->if_type == IFT_CARP ||
> + !carp_iamatch6(ifp, lladdr, &proxydl))
> + goto freeit;
> +#endif
> log(LOG_ERR,
> "nd6_na_input: duplicate IP6 address %s\n",
> inet_ntop(AF_INET6, &taddr6, addr, sizeof(addr)));
>
