From bd2d8190dd79645174beeef1a306c8df53db3b60 Mon Sep 17 00:00:00 2001
From: Martin Mares <mj@ucw.cz>
Date: Mon, 17 Apr 2000 13:13:08 +0000
Subject: [PATCH] Honor standard communities (no_export, no_advertise,
no_export_subconfed) when exporting routes.
---
proto/bgp/attrs.c | 41 +++++++++++++++++++++++++++++++++++++----
proto/bgp/bgp.h | 6 ++++++
2 files changed, 43 insertions(+), 4 deletions(-)
diff --git a/proto/bgp/attrs.c b/proto/bgp/attrs.c
index 22c73ca90..03f8ed37a 100644
--- a/proto/bgp/attrs.c
+++ b/proto/bgp/attrs.c
@@ -297,6 +297,42 @@ bgp_new_bucket(struct bgp_proto *p, ea_list *new, unsigned hash)
return b;
}
+static int
+bgp_export_check(struct bgp_proto *p, ea_list *new)
+{
+ eattr *a;
+ struct adata *d;
+
+ /* Check if next hop is valid */
+ a = ea_find(new, EA_CODE(EAP_BGP, BA_NEXT_HOP));
+ if (!a || ipa_equal(p->next_hop, *(ip_addr *)a->u.ptr))
+ {
+ DBG("\tInvalid NEXT_HOP\n");
+ return 0;
+ }
+
+ /* Check if we aren't forbidden to export the route by communities */
+ a = ea_find(new, EA_CODE(EAP_BGP, BA_COMMUNITY));
+ if (a)
+ {
+ d = a->u.ptr;
+ if (int_set_contains(d, BGP_COMM_NO_ADVERTISE))
+ {
+ DBG("\tNO_ADVERTISE\n");
+ return 0;
+ }
+ if (!p->is_internal &&
+ (int_set_contains(d, BGP_COMM_NO_EXPORT) ||
+ int_set_contains(d, BGP_COMM_NO_EXPORT_SUBCONFED)))
+ {
+ DBG("\tNO_EXPORT\n");
+ return 0;
+ }
+ }
+
+ return 1;
+}
+
static struct bgp_bucket *
bgp_get_bucket(struct bgp_proto *p, ea_list *old, ea_list *tmp, int originate)
{
@@ -375,10 +411,7 @@ bgp_get_bucket(struct bgp_proto *p, ea_list *old, ea_list *tmp, int originate)
return NULL;
}
- /* Check if next hop is valid */
- a = ea_find(new, EA_CODE(EAP_BGP, BA_NEXT_HOP));
- ASSERT(a);
- if (ipa_equal(p->next_hop, *(ip_addr *)a->u.ptr))
+ if (!bgp_export_check(p, new))
return NULL;
/* Create new bucket */
diff --git a/proto/bgp/bgp.h b/proto/bgp/bgp.h
index ba4f2d4ba..f579ce66f 100644
--- a/proto/bgp/bgp.h
+++ b/proto/bgp/bgp.h
@@ -151,4 +151,10 @@ int bgp_rx(struct birdsock *sk, int size);
#define BS_OPENCONFIRM 4
#define BS_ESTABLISHED 5
+/* Well-known communities */
+
+#define BGP_COMM_NO_EXPORT 0xffffff01 /* Don't export outside local AS / confed. */
+#define BGP_COMM_NO_ADVERTISE 0xffffff02 /* Don't export at all */
+#define BGP_COMM_NO_EXPORT_SUBCONFED 0xffffff03 /* NO_EXPORT even in local confederation */
+
#endif