On Mon, Sep 26, 2016 at 11:14:51PM +0200, Sebastian Benoit wrote:
> 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.
>
I know cisco has a similar feature. Can someone of you check how it
detects AS loops? If it does at all. I guess people expect it to work
similar to other vendors.
> 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!!!!"
> >
>
--
:wq Claudio
