bgpd: implement route-map set as-path prepend last-as
It picks up the AS to add from the aspath, or uses the peers
AS number. Useful mostly in iBGP setups.
Signed-off-by: Timo Teräs <timo.teras@iki.fi>
Reviewed-by: Paul Jakma <paul@opensourcerouting.org>
diff --git a/bgpd/bgp_aspath.c b/bgpd/bgp_aspath.c
index e8559be..cfa9bc1 100644
--- a/bgpd/bgp_aspath.c
+++ b/bgpd/bgp_aspath.c
@@ -476,6 +476,19 @@
return highest;
}
+/* Return the left-most ASN in path */
+as_t
+aspath_leftmost (struct aspath *aspath)
+{
+ struct assegment *seg = aspath->segments;
+ as_t leftmost = 0;
+
+ if (seg && seg->length && seg->type == AS_SEQUENCE)
+ leftmost = seg->as[0];
+
+ return leftmost;
+}
+
/* Return 1 if there are any 4-byte ASes in the path */
unsigned int
aspath_has_as4 (struct aspath *aspath)
@@ -1362,46 +1375,50 @@
/* Add specified AS to the leftmost of aspath. */
static struct aspath *
-aspath_add_one_as (struct aspath *aspath, as_t asno, u_char type)
+aspath_add_asns (struct aspath *aspath, as_t asno, u_char type, unsigned num)
{
struct assegment *assegment = aspath->segments;
+ int i;
- /* In case of empty aspath. */
- if (assegment == NULL || assegment->length == 0)
+ if (assegment && assegment->type == type)
{
- aspath->segments = assegment_new (type, 1);
- aspath->segments->as[0] = asno;
-
- if (assegment)
- assegment_free (assegment);
-
- return aspath;
+ /* extend existing segment */
+ aspath->segments = assegment_prepend_asns (aspath->segments, asno, num);
}
-
- if (assegment->type == type)
- aspath->segments = assegment_prepend_asns (aspath->segments, asno, 1);
else
{
- /* create new segment
- * push it onto head of aspath's segment chain
- */
- struct assegment *newsegment;
-
- newsegment = assegment_new (type, 1);
- newsegment->as[0] = asno;
-
- newsegment->next = assegment;
+ /* prepend with new segment */
+ struct assegment *newsegment = assegment_new (type, num);
+ for (i = 0; i < num; i++)
+ newsegment->as[i] = asno;
+
+ /* insert potentially replacing empty segment */
+ if (assegment && assegment->length == 0)
+ {
+ newsegment->next = assegment->next;
+ assegment_free (assegment);
+ }
+ else
+ newsegment->next = assegment;
aspath->segments = newsegment;
}
+ aspath_str_update (aspath);
return aspath;
}
+/* Add specified AS to the leftmost of aspath num times. */
+struct aspath *
+aspath_add_seq_n (struct aspath *aspath, as_t asno, unsigned num)
+{
+ return aspath_add_asns (aspath, asno, AS_SEQUENCE, num);
+}
+
/* Add specified AS to the leftmost of aspath. */
struct aspath *
aspath_add_seq (struct aspath *aspath, as_t asno)
{
- return aspath_add_one_as (aspath, asno, AS_SEQUENCE);
+ return aspath_add_asns (aspath, asno, AS_SEQUENCE, 1);
}
/* Compare leftmost AS value for MED check. If as1's leftmost AS and
@@ -1600,7 +1617,7 @@
struct aspath*
aspath_add_confed_seq (struct aspath *aspath, as_t asno)
{
- return aspath_add_one_as (aspath, asno, AS_CONFED_SEQUENCE);
+ return aspath_add_asns (aspath, asno, AS_CONFED_SEQUENCE, 1);
}
/* Add new as value to as path structure. */