diff options
Diffstat (limited to 'proto/bgp/attrs.c')
| -rw-r--r-- | proto/bgp/attrs.c | 46 |
1 files changed, 36 insertions, 10 deletions
diff --git a/proto/bgp/attrs.c b/proto/bgp/attrs.c index b5d8fba..2210cbe 100644 --- a/proto/bgp/attrs.c +++ b/proto/bgp/attrs.c @@ -146,7 +146,7 @@ static struct attr_desc bgp_attr_table[] = { bgp_check_as_path, NULL }, { "next_hop", 4, BAF_TRANSITIVE, EAF_TYPE_IP_ADDRESS, 1, /* BA_NEXT_HOP */ bgp_check_next_hop, NULL }, - { "med", 4, BAF_OPTIONAL, EAF_TYPE_INT, 0, /* BA_MULTI_EXIT_DISC */ + { "med", 4, BAF_OPTIONAL, EAF_TYPE_INT, 1, /* BA_MULTI_EXIT_DISC */ NULL, NULL }, { "local_pref", 4, BAF_TRANSITIVE, EAF_TYPE_INT, 0, /* BA_LOCAL_PREF */ NULL, NULL }, @@ -829,7 +829,17 @@ bgp_update_attrs(struct bgp_proto *p, rte *e, ea_list **attrs, struct linpool *p eattr *a; if (!p->is_internal) - bgp_path_prepend(e, attrs, pool, p->local_as); + { + bgp_path_prepend(e, attrs, pool, p->local_as); + + /* The MULTI_EXIT_DISC attribute received from a neighboring AS MUST NOT be + * propagated to other neighboring ASes. + * Perhaps it would be better to undefine it. + */ + a = ea_find(e->attrs->eattrs, EA_CODE(EAP_BGP, BA_MULTI_EXIT_DISC)); + if (a) + bgp_attach_attr(attrs, pool, BA_MULTI_EXIT_DISC, 0); + } a = ea_find(e->attrs->eattrs, EA_CODE(EAP_BGP, BA_NEXT_HOP)); if (a && (p->is_internal || (!p->is_internal && e->attrs->iface == p->neigh->iface))) @@ -894,6 +904,18 @@ bgp_import_control(struct proto *P, rte **new, ea_list **attrs, struct linpool * return bgp_create_attrs(p, e, attrs, pool); } +static inline u32 +bgp_get_neighbor(rte *r) +{ + eattr *e = ea_find(r->attrs->eattrs, EA_CODE(EAP_BGP, BA_AS_PATH)); + u32 as; + + if (e && as_path_get_last(e->u.ptr, &as)) + return as; + else + return ((struct bgp_proto *) r->attrs->proto)->remote_as; +} + int bgp_rte_better(rte *new, rte *old) { @@ -936,14 +958,18 @@ bgp_rte_better(rte *new, rte *old) return 0; /* RFC 4271 9.1.2.2. c) Compare MED's */ - x = ea_find(new->attrs->eattrs, EA_CODE(EAP_BGP, BA_MULTI_EXIT_DISC)); - y = ea_find(old->attrs->eattrs, EA_CODE(EAP_BGP, BA_MULTI_EXIT_DISC)); - n = x ? x->u.data : new_bgp->cf->default_med; - o = y ? y->u.data : old_bgp->cf->default_med; - if (n < o) - return 1; - if (n > o) - return 0; + + if (bgp_get_neighbor(new) == bgp_get_neighbor(old)) + { + x = ea_find(new->attrs->eattrs, EA_CODE(EAP_BGP, BA_MULTI_EXIT_DISC)); + y = ea_find(old->attrs->eattrs, EA_CODE(EAP_BGP, BA_MULTI_EXIT_DISC)); + n = x ? x->u.data : new_bgp->cf->default_med; + o = y ? y->u.data : old_bgp->cf->default_med; + if (n < o) + return 1; + if (n > o) + return 0; + } /* RFC 4271 9.1.2.2. d) Prefer external peers */ if (new_bgp->is_internal > old_bgp->is_internal) |