If we do this, i think the as-path loop detection needs to also check for
these additional ASes.
Otherwise we create a nice loop when we get our own route
from an ebgp neighbor with this as in the path.
Peter Hessler(phess...@openbsd.org) on 2016.09.26 20:09:13 +0200:
> We already have a local AS saved per peer. Let's use it. This is very
> useful when one needs to change their local AS.
>
> "
> neighbor 192.0.2.1 {
> remote-as 65530
> local-as 131000
> }
> "
>
> OK?
>
>
> Index: parse.y
> ===================================================================
> RCS file: /cvs/openbsd/src/usr.sbin/bgpd/parse.y,v
> retrieving revision 1.288
> diff -u -p -u -p -r1.288 parse.y
> --- parse.y 21 Jun 2016 21:35:24 -0000 1.288
> +++ parse.y 26 Sep 2016 14:46:23 -0000
> @@ -175,7 +175,7 @@ typedef struct {
> %token RDOMAIN RD EXPORTTRGT IMPORTTRGT
> %token RDE RIB EVALUATE IGNORE COMPARE
> %token GROUP NEIGHBOR NETWORK
> -%token REMOTEAS DESCR LOCALADDR MULTIHOP PASSIVE MAXPREFIX RESTART
> +%token LOCALAS REMOTEAS DESCR LOCALADDR MULTIHOP PASSIVE MAXPREFIX
> RESTART
> %token ANNOUNCE CAPABILITIES REFRESH AS4BYTE CONNECTRETRY
> %token DEMOTE ENFORCE NEIGHBORAS REFLECTOR DEPEND DOWN SOFTRECONFIG
> %token DUMP IN OUT SOCKET RESTRICTED
> @@ -1004,6 +1004,9 @@ peeroptsl : peeropts nl
> peeropts : REMOTEAS as4number {
> curpeer->conf.remote_as = $2;
> }
> + | LOCALAS as4number {
> + curpeer->conf.local_as = $2;
> + }
> | DESCR string {
> if (strlcpy(curpeer->conf.descr, $2,
> sizeof(curpeer->conf.descr)) >=
> @@ -2249,6 +2252,7 @@ lookup(char *s)
> { "key", KEY},
> { "listen", LISTEN},
> { "local-address", LOCALADDR},
> + { "local-as", LOCALAS},
> { "localpref", LOCALPREF},
> { "log", LOG},
> { "match", MATCH},
> Index: printconf.c
> ===================================================================
> RCS file: /cvs/openbsd/src/usr.sbin/bgpd/printconf.c,v
> retrieving revision 1.97
> diff -u -p -u -p -r1.97 printconf.c
> --- printconf.c 13 Jul 2016 20:07:38 -0000 1.97
> +++ printconf.c 26 Sep 2016 17:41:58 -0000
> @@ -365,6 +365,8 @@ print_peer(struct peer_config *p, struct
> printf("%s\trib \"%s\"\n", c, p->rib);
> if (p->remote_as)
> printf("%s\tremote-as %s\n", c, log_as(p->remote_as));
> + if (p->local_as != conf->as)
> + printf("%s\tlocale-as %s\n", c, log_as(p->local_as));
> if (p->down)
> printf("%s\tdown\n", c);
> if (p->distance > 1)
> Index: session.c
> ===================================================================
> RCS file: /cvs/openbsd/src/usr.sbin/bgpd/session.c,v
> retrieving revision 1.354
> diff -u -p -u -p -r1.354 session.c
> --- session.c 3 Sep 2016 16:22:17 -0000 1.354
> +++ session.c 26 Sep 2016 17:47:59 -0000
> @@ -1461,7 +1461,7 @@ session_open(struct peer *p)
> if (p->capa.ann.as4byte) { /* 4 bytes data */
> u_int32_t nas;
>
> - nas = htonl(conf->as);
> + nas = htonl(p->conf.local_as);
> errs += session_capa_add(opb, CAPA_AS4BYTE, sizeof(nas));
> errs += ibuf_add(opb, &nas, sizeof(nas));
> }
> @@ -2120,7 +2120,7 @@ parse_open(struct peer *peer)
> /* if remote-as is zero and it's a cloned neighbor, accept any */
> if (peer->template && !peer->conf.remote_as && as != AS_TRANS) {
> peer->conf.remote_as = as;
> - peer->conf.ebgp = (peer->conf.remote_as != conf->as);
> + peer->conf.ebgp = (peer->conf.remote_as != peer->conf.local_as);
> if (!peer->conf.ebgp)
> /* force enforce_as off for iBGP sessions */
> peer->conf.enforce_as = ENFORCE_AS_OFF;
> @@ -3074,7 +3074,7 @@ session_template_clone(struct peer *p, s
>
> if (as) {
> p->conf.remote_as = as;
> - p->conf.ebgp = (p->conf.remote_as != conf->as);
> + p->conf.ebgp = (p->conf.remote_as != p->conf.local_as);
> if (!p->conf.ebgp)
> /* force enforce_as off for iBGP sessions */
> p->conf.enforce_as = ENFORCE_AS_OFF;
> Index: bgpd.conf.5
> ===================================================================
> RCS file: /cvs/openbsd/src/usr.sbin/bgpd/bgpd.conf.5,v
> retrieving revision 1.146
> diff -u -p -u -p -r1.146 bgpd.conf.5
> --- bgpd.conf.5 17 Aug 2016 08:14:40 -0000 1.146
> +++ bgpd.conf.5 26 Sep 2016 18:03:06 -0000
> @@ -855,6 +855,10 @@ is given,
> .Xr bgpd 8
> binds to this address first.
> .Pp
> +.It Ic local-as Ar as-number
> +Set the AS number sent to the remote system.
> +Intended to be used temporarily, for migrations to another AS.
> +.Pp
> .It Ic log no
> Disable neighbor specific logging.
> .Pp
>
>
>
> --
> "But I don't like Spam!!!!"
>
