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authorOndrej Zajicek <santiago@crfreenet.org>2008-10-26 22:45:09 +0100
committerOndrej Zajicek <santiago@crfreenet.org>2008-10-26 22:45:09 +0100
commit4847a894bf7d4852325c3f1ea4bb4890054a1f66 (patch)
tree46d0f400b9e6fc3dfaf64d7058c473e44501ddc1 /proto/bgp/attrs.c
parentd51aa2819005a03e4cfb6f62333be6ccadfb3c06 (diff)
downloadbird-4847a894bf7d4852325c3f1ea4bb4890054a1f66.tar
bird-4847a894bf7d4852325c3f1ea4bb4890054a1f66.zip
Implementation of route reflection for BGP
Diffstat (limited to 'proto/bgp/attrs.c')
-rw-r--r--proto/bgp/attrs.c223
1 files changed, 161 insertions, 62 deletions
diff --git a/proto/bgp/attrs.c b/proto/bgp/attrs.c
index 48cb9dd..a42a488 100644
--- a/proto/bgp/attrs.c
+++ b/proto/bgp/attrs.c
@@ -104,7 +104,7 @@ bgp_check_next_hop(struct bgp_proto *p UNUSED, byte *a, int len)
}
static int
-bgp_check_aggregator(struct bgp_proto *p UNUSED, UNUSED byte *a, int len)
+bgp_check_aggregator(struct bgp_proto *p, UNUSED byte *a, int len)
{
int exp_len = (bgp_as4_support && p->as4_support) ? 8 : 6;
@@ -112,6 +112,12 @@ bgp_check_aggregator(struct bgp_proto *p UNUSED, UNUSED byte *a, int len)
}
static int
+bgp_check_cluster_list(struct bgp_proto *p UNUSED, UNUSED byte *a, int len)
+{
+ return ((len % 4) == 0) ? 0 : 5;
+}
+
+static int
bgp_check_reach_nlri(struct bgp_proto *p UNUSED, byte *a UNUSED, int len UNUSED)
{
#ifdef IPV6
@@ -150,8 +156,10 @@ static struct attr_desc bgp_attr_table[] = {
bgp_check_aggregator, NULL },
{ "community", -1, BAF_OPTIONAL | BAF_TRANSITIVE, EAF_TYPE_INT_SET, 1, /* BA_COMMUNITY */
NULL, NULL },
- { NULL, }, /* BA_ORIGINATOR_ID */
- { NULL, }, /* BA_CLUSTER_LIST */
+ { "originator_id", 4, BAF_OPTIONAL, EAF_TYPE_INT, 0, /* BA_ORIGINATOR_ID */
+ NULL, NULL },
+ { "cluster_list", -1, BAF_OPTIONAL, EAF_TYPE_INT_SET, 0, /* BA_CLUSTER_LIST */
+ bgp_check_cluster_list, NULL },
{ NULL, }, /* BA_DPA */
{ NULL, }, /* BA_ADVERTISER */
{ NULL, }, /* BA_RCID_PATH */
@@ -173,35 +181,52 @@ static struct attr_desc bgp_attr_table[] = {
#define ATTR_KNOWN(code) ((code) < ARRAY_SIZE(bgp_attr_table) && bgp_attr_table[code].name)
-static byte *
-bgp_set_attr(eattr *e, struct linpool *pool, unsigned attr, unsigned val)
+static inline struct adata *
+bgp_alloc_adata(struct linpool *pool, unsigned len)
+{
+ struct adata *ad = lp_alloc(pool, sizeof(struct adata) + len);
+ ad->length = len;
+ return ad;
+}
+
+static void
+bgp_set_attr(eattr *e, unsigned attr, uintptr_t val)
{
ASSERT(ATTR_KNOWN(attr));
e->id = EA_CODE(EAP_BGP, attr);
e->type = bgp_attr_table[attr].type;
e->flags = bgp_attr_table[attr].expected_flags;
if (e->type & EAF_EMBEDDED)
- {
- e->u.data = val;
- return NULL;
- }
+ e->u.data = val;
else
- {
- e->u.ptr = lp_alloc(pool, sizeof(struct adata) + val);
- e->u.ptr->length = val;
- return e->u.ptr->data;
- }
+ e->u.ptr = (struct adata *) val;
}
-byte *
-bgp_attach_attr(ea_list **to, struct linpool *pool, unsigned attr, unsigned val)
+static byte *
+bgp_set_attr_wa(eattr *e, struct linpool *pool, unsigned attr, unsigned len)
+{
+ struct adata *ad = bgp_alloc_adata(pool, len);
+ bgp_set_attr(e, attr, (uintptr_t) ad);
+ return ad->data;
+}
+
+void
+bgp_attach_attr(ea_list **to, struct linpool *pool, unsigned attr, uintptr_t val)
{
ea_list *a = lp_alloc(pool, sizeof(ea_list) + sizeof(eattr));
a->next = *to;
*to = a;
a->flags = EALF_SORTED;
a->count = 1;
- return bgp_set_attr(a->attrs, pool, attr, val);
+ bgp_set_attr(a->attrs, attr, val);
+}
+
+byte *
+bgp_attach_attr_wa(ea_list **to, struct linpool *pool, unsigned attr, unsigned len)
+{
+ struct adata *ad = bgp_alloc_adata(pool, len);
+ bgp_attach_attr(to, pool, attr, (uintptr_t) ad);
+ return ad->data;
}
static int
@@ -713,6 +738,7 @@ bgp_rt_notify(struct proto *P, net *n, rte *new, rte *old UNUSED, ea_list *attrs
bgp_schedule_packet(p->conn, PKT_UPDATE);
}
+
static int
bgp_create_attrs(struct bgp_proto *p, rte *e, ea_list **attrs, struct linpool *pool)
{
@@ -725,14 +751,14 @@ bgp_create_attrs(struct bgp_proto *p, rte *e, ea_list **attrs, struct linpool *p
ea->flags = EALF_SORTED;
ea->count = 4;
- bgp_set_attr(ea->attrs, pool, BA_ORIGIN,
+ bgp_set_attr(ea->attrs, BA_ORIGIN,
((rta->source == RTS_OSPF_EXT1) || (rta->source == RTS_OSPF_EXT2)) ? ORIGIN_INCOMPLETE : ORIGIN_IGP);
if (p->is_internal)
- bgp_set_attr(ea->attrs+1, pool, BA_AS_PATH, 0);
+ bgp_set_attr_wa(ea->attrs+1, pool, BA_AS_PATH, 0);
else
{
- z = bgp_set_attr(ea->attrs+1, pool, BA_AS_PATH, bgp_as4_support ? 6 : 4);
+ z = bgp_set_attr_wa(ea->attrs+1, pool, BA_AS_PATH, bgp_as4_support ? 6 : 4);
z[0] = AS_PATH_SEQUENCE;
z[1] = 1; /* 1 AS */
@@ -742,7 +768,7 @@ bgp_create_attrs(struct bgp_proto *p, rte *e, ea_list **attrs, struct linpool *p
put_u16(z+2, p->local_as);
}
- z = bgp_set_attr(ea->attrs+2, pool, BA_NEXT_HOP, sizeof(ip_addr));
+ z = bgp_set_attr_wa(ea->attrs+2, pool, BA_NEXT_HOP, sizeof(ip_addr));
if (p->cf->next_hop_self ||
!p->is_internal ||
rta->dest != RTD_ROUTER)
@@ -755,34 +781,55 @@ bgp_create_attrs(struct bgp_proto *p, rte *e, ea_list **attrs, struct linpool *p
else
*(ip_addr *)z = e->attrs->gw;
- bgp_set_attr(ea->attrs+3, pool, BA_LOCAL_PREF, 0);
+ bgp_set_attr(ea->attrs+3, BA_LOCAL_PREF, 0);
return 0; /* Leave decision to the filters */
}
-static ea_list *
-bgp_path_prepend(struct linpool *pool, eattr *a, ea_list *old, int as)
+
+static inline int
+bgp_as_path_loopy(struct bgp_proto *p, rta *a)
+{
+ eattr *e = ea_find(a->eattrs, EA_CODE(EAP_BGP, BA_AS_PATH));
+ return (e && as_path_is_member(e->u.ptr, p->local_as));
+}
+
+static inline int
+bgp_originator_id_loopy(struct bgp_proto *p, rta *a)
{
- struct ea_list *e = lp_alloc(pool, sizeof(ea_list) + sizeof(eattr));
- struct adata *olda = a->u.ptr;
-
- e->next = old;
- e->flags = EALF_SORTED;
- e->count = 1;
- e->attrs[0].id = EA_CODE(EAP_BGP, BA_AS_PATH);
- e->attrs[0].flags = BAF_TRANSITIVE;
- e->attrs[0].type = EAF_TYPE_AS_PATH;
- e->attrs[0].u.ptr = as_path_prepend(pool, olda, as);
- return e;
+ eattr *e = ea_find(a->eattrs, EA_CODE(EAP_BGP, BA_ORIGINATOR_ID));
+ return (e && (e->u.data == p->local_id));
+}
+
+static inline int
+bgp_cluster_list_loopy(struct bgp_proto *p, rta *a)
+{
+ eattr *e = ea_find(a->eattrs, EA_CODE(EAP_BGP, BA_CLUSTER_LIST));
+ return (e && p->rr_client && int_set_contains(e->u.ptr, p->rr_cluster_id));
+}
+
+
+static inline void
+bgp_path_prepend(rte *e, ea_list **attrs, struct linpool *pool, u32 as)
+{
+ eattr *a = ea_find(e->attrs->eattrs, EA_CODE(EAP_BGP, BA_AS_PATH));
+ bgp_attach_attr(attrs, pool, BA_AS_PATH, (uintptr_t) as_path_prepend(pool, a->u.ptr, as));
+}
+
+static inline void
+bgp_cluster_list_prepend(rte *e, ea_list **attrs, struct linpool *pool, u32 cid)
+{
+ eattr *a = ea_find(e->attrs->eattrs, EA_CODE(EAP_BGP, BA_CLUSTER_LIST));
+ bgp_attach_attr(attrs, pool, BA_CLUSTER_LIST, (uintptr_t) int_set_add(pool, a ? a->u.ptr : NULL, cid));
}
static int
-bgp_update_attrs(struct bgp_proto *p, rte *e, ea_list **attrs, struct linpool *pool)
+bgp_update_attrs(struct bgp_proto *p, rte *e, ea_list **attrs, struct linpool *pool, int rr)
{
eattr *a;
- if (!p->is_internal && (a = ea_find(e->attrs->eattrs, EA_CODE(EAP_BGP, BA_AS_PATH))))
- *attrs = bgp_path_prepend(pool, a, *attrs, p->local_as);
+ if (!p->is_internal)
+ bgp_path_prepend(e, attrs, pool, p->local_as);
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)))
@@ -792,7 +839,24 @@ bgp_update_attrs(struct bgp_proto *p, rte *e, ea_list **attrs, struct linpool *p
else
{
/* Need to create new one */
- *(ip_addr *) bgp_attach_attr(attrs, pool, BA_NEXT_HOP, sizeof(ip_addr)) = p->local_addr;
+ bgp_attach_attr_ip(attrs, pool, BA_NEXT_HOP, p->local_addr);
+ }
+
+ if (rr)
+ {
+ /* Handling route reflection, RFC 4456 */
+ struct bgp_proto *src = (struct bgp_proto *) e->attrs->proto;
+
+ a = ea_find(e->attrs->eattrs, EA_CODE(EAP_BGP, BA_ORIGINATOR_ID));
+ if (!a)
+ bgp_attach_attr(attrs, pool, BA_ORIGINATOR_ID, src->remote_id);
+
+ /* We attach proper cluster ID according to whether the route is entering or leaving the cluster */
+ bgp_cluster_list_prepend(e, attrs, pool, src->rr_client ? src->rr_cluster_id : p->rr_cluster_id);
+
+ /* Two RR clients with different cluster ID, hmmm */
+ if (src->rr_client && p->rr_client && (src->rr_cluster_id != p->rr_cluster_id))
+ bgp_cluster_list_prepend(e, attrs, pool, p->rr_cluster_id);
}
return 0; /* Leave decision to the filters */
@@ -809,9 +873,22 @@ bgp_import_control(struct proto *P, rte **new, ea_list **attrs, struct linpool *
return -1;
if (new_bgp)
{
+ /* We should check here for cluster list loop, because the receiving BGP instance
+ might have different cluster ID */
+ if (bgp_cluster_list_loopy(p, e->attrs))
+ return -1;
+
if (p->local_as == new_bgp->local_as && p->is_internal && new_bgp->is_internal)
- return -1; /* Don't redistribute internal routes with IBGP */
- return bgp_update_attrs(p, e, attrs, pool);
+ {
+ /* Redistribution of internal routes with IBGP */
+ if (p->rr_client || new_bgp->rr_client)
+ /* Route reflection, RFC 4456 */
+ return bgp_update_attrs(p, e, attrs, pool, 1);
+ else
+ return -1;
+ }
+ else
+ return bgp_update_attrs(p, e, attrs, pool, 0);
}
else
return bgp_create_attrs(p, e, attrs, pool);
@@ -835,7 +912,7 @@ bgp_rte_better(rte *new, rte *old)
if (n < o)
return 0;
- /* Use AS path lengths */
+ /* RFC 4271 9.1.2.2. a) Use AS path lengths */
if (new_bgp->cf->compare_path_lengths || old_bgp->cf->compare_path_lengths)
{
x = ea_find(new->attrs->eattrs, EA_CODE(EAP_BGP, BA_AS_PATH));
@@ -848,7 +925,7 @@ bgp_rte_better(rte *new, rte *old)
return 0;
}
- /* Use origins */
+ /* RFC 4271 9.1.2.2. b) Use origins */
x = ea_find(new->attrs->eattrs, EA_CODE(EAP_BGP, BA_ORIGIN));
y = ea_find(old->attrs->eattrs, EA_CODE(EAP_BGP, BA_ORIGIN));
n = x ? x->u.data : ORIGIN_INCOMPLETE;
@@ -858,7 +935,7 @@ bgp_rte_better(rte *new, rte *old)
if (n > o)
return 0;
- /* Compare MED's */
+ /* 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;
@@ -868,24 +945,41 @@ bgp_rte_better(rte *new, rte *old)
if (n > o)
return 0;
- /* A tie breaking procedure according to RFC 1771, section 9.1.2.1 */
- /* We don't have interior distances */
- /* We prefer external peers */
+ /* RFC 4271 9.1.2.2. d) Prefer external peers */
if (new_bgp->is_internal > old_bgp->is_internal)
return 0;
if (new_bgp->is_internal < old_bgp->is_internal)
return 1;
- /* Finally we compare BGP identifiers */
- return (new_bgp->remote_id < old_bgp->remote_id);
-}
-static int
-bgp_path_loopy(struct bgp_proto *p, eattr *a)
-{
- return as_path_is_member(a->u.ptr, p->local_as);
-}
+ /* Skipping RFC 4271 9.1.2.2. e) */
+ /* We don't have interior distances */
+
+ /* RFC 4456 9. b) Compare cluster list lengths */
+ x = ea_find(new->attrs->eattrs, EA_CODE(EAP_BGP, BA_CLUSTER_LIST));
+ y = ea_find(old->attrs->eattrs, EA_CODE(EAP_BGP, BA_CLUSTER_LIST));
+ n = x ? int_set_get_size(x->u.ptr) : 0;
+ o = y ? int_set_get_size(y->u.ptr) : 0;
+ if (n < o)
+ return 1;
+ if (n > o)
+ return 0;
+
+ /* RFC 4271 9.1.2.2. f) Compare BGP identifiers */
+ /* RFC 4456 9. a) Use ORIGINATOR_ID instead of local neighor ID */
+ x = ea_find(new->attrs->eattrs, EA_CODE(EAP_BGP, BA_ORIGINATOR_ID));
+ y = ea_find(old->attrs->eattrs, EA_CODE(EAP_BGP, BA_ORIGINATOR_ID));
+ n = x ? x->u.data : new_bgp->remote_id;
+ o = y ? y->u.data : old_bgp->remote_id;
+ if (n < o)
+ return 1;
+ if (n > o)
+ return 0;
+ /* RFC 4271 9.1.2.2. g) Compare peer IP adresses */
+ return (ipa_compare(new_bgp->cf->remote_ip, old_bgp->cf->remote_ip) < 0);
+}
+
static struct adata *
bgp_aggregator_convert_to_new(struct adata *old, struct linpool *pool)
{
@@ -916,7 +1010,7 @@ bgp_merge_as_paths(struct adata *old2, struct adata *old4, int req_as, struct li
}
-/* Reconstruct 4B AS_PATH and AGGREGATOR according to RFC4893 4.2.3 */
+/* Reconstruct 4B AS_PATH and AGGREGATOR according to RFC 4893 4.2.3 */
static void
bgp_reconstruct_4b_atts(struct bgp_proto *p, rta *a, struct linpool *pool)
{
@@ -1159,18 +1253,23 @@ bgp_decode_attrs(struct bgp_conn *conn, byte *attr, unsigned int len, struct lin
bgp_remove_as4_attrs(bgp, a);
/* If the AS path attribute contains our AS, reject the routes */
- e = ea_find(a->eattrs, EA_CODE(EAP_BGP, BA_AS_PATH));
- if (e && bgp_path_loopy(bgp, e))
- {
- DBG("BGP: Path loop!\n");
- return NULL;
- }
+ if (bgp_as_path_loopy(bgp, a))
+ goto loop;
+
+ /* Two checks for IBGP loops caused by route reflection, RFC 4456 */
+ if (bgp_originator_id_loopy(bgp, a) ||
+ bgp_cluster_list_loopy(bgp, a))
+ goto loop;
/* If there's no local preference, define one */
if (!(seen[0] && (1 << BA_LOCAL_PREF)))
bgp_attach_attr(&a->eattrs, pool, BA_LOCAL_PREF, 0);
return a;
+loop:
+ DBG("BGP: Path loop!\n");
+ return NULL;
+
malformed:
bgp_error(conn, 3, 1, NULL, 0);
return NULL;