bgpd: Implement BGP confederation error handling (RFC5065, Par. 5)
This patch implements BGP confederation error handling in Quagga as described
in RFC5065, paragraph 5.
* bgp_aspath.c: (aspath_confed_check, aspath_left_confed_check) new functions
* bgp_attr.c: (bgp_attr_aspath_check) apply previous and NOTIFY if there's
a problem.
diff --git a/bgpd/bgp_aspath.c b/bgpd/bgp_aspath.c
index 13f32b8..e65541f 100644
--- a/bgpd/bgp_aspath.c
+++ b/bgpd/bgp_aspath.c
@@ -1122,6 +1122,42 @@
return 1;
}
+/* AS path confed check. If aspath contains confed set or sequence then return 1. */
+int
+aspath_confed_check (struct aspath *aspath)
+{
+ struct assegment *seg;
+
+ if ( !(aspath && aspath->segments) )
+ return 0;
+
+ seg = aspath->segments;
+
+ while (seg)
+ {
+ if (seg->type == AS_CONFED_SET || seg->type == AS_CONFED_SEQUENCE)
+ return 1;
+ seg = seg->next;
+ }
+ return 0;
+}
+
+/* Leftmost AS path segment confed check. If leftmost AS segment is of type
+ AS_CONFED_SEQUENCE or AS_CONFED_SET then return 1. */
+int
+aspath_left_confed_check (struct aspath *aspath)
+{
+
+ if ( !(aspath && aspath->segments) )
+ return 0;
+
+ if ( (aspath->segments->type == AS_CONFED_SEQUENCE)
+ || (aspath->segments->type == AS_CONFED_SET) )
+ return 1;
+
+ return 0;
+}
+
/* Merge as1 to as2. as2 should be uninterned aspath. */
static struct aspath *
aspath_merge (struct aspath *as1, struct aspath *as2)
diff --git a/bgpd/bgp_aspath.h b/bgpd/bgp_aspath.h
index 2b4625c..9854d18 100644
--- a/bgpd/bgp_aspath.h
+++ b/bgpd/bgp_aspath.h
@@ -88,6 +88,8 @@
extern int aspath_loop_check (struct aspath *, as_t);
extern int aspath_private_as_check (struct aspath *);
extern int aspath_firstas_check (struct aspath *, as_t);
+extern int aspath_confed_check (struct aspath *);
+extern int aspath_left_confed_check (struct aspath *);
extern unsigned long aspath_count (void);
extern unsigned int aspath_count_hops (struct aspath *);
extern unsigned int aspath_count_confeds (struct aspath *);
diff --git a/bgpd/bgp_attr.c b/bgpd/bgp_attr.c
index 9416837..a664858 100644
--- a/bgpd/bgp_attr.c
+++ b/bgpd/bgp_attr.c
@@ -872,6 +872,17 @@
bgp = peer->bgp;
+ /* Confederation sanity check. */
+ if ((peer_sort (peer) == BGP_PEER_CONFED && ! aspath_left_confed_check (attr->aspath)) ||
+ (peer_sort (peer) == BGP_PEER_EBGP && aspath_confed_check (attr->aspath)))
+ {
+ zlog (peer->log, LOG_ERR, "Malformed AS path from %s", peer->host);
+ bgp_notify_send (peer,
+ BGP_NOTIFY_UPDATE_ERR,
+ BGP_NOTIFY_UPDATE_MAL_AS_PATH);
+ return -1;
+ }
+
/* First AS check for EBGP. */
if (bgp != NULL && bgp_flag_check (bgp, BGP_FLAG_ENFORCE_FIRST_AS))
{