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_routemap.c b/bgpd/bgp_routemap.c
index b74554d..857781f 100644
--- a/bgpd/bgp_routemap.c
+++ b/bgpd/bgp_routemap.c
@@ -1230,7 +1230,6 @@
if (type == RMAP_BGP)
{
- aspath = rule;
binfo = object;
if (binfo->attr->aspath->refcnt)
@@ -1238,20 +1237,50 @@
else
new = binfo->attr->aspath;
- aspath_prepend (aspath, new);
+ if ((uintptr_t)rule > 10)
+ {
+ aspath = rule;
+ aspath_prepend (aspath, new);
+ }
+ else
+ {
+ as_t as = aspath_leftmost(new);
+ if (!as) as = binfo->peer->as;
+ new = aspath_add_seq_n (new, as, (uintptr_t) rule);
+ }
+
binfo->attr->aspath = new;
}
return RMAP_OKAY;
}
+static void *
+route_set_aspath_prepend_compile (const char *arg)
+{
+ unsigned int num;
+
+ if (sscanf(arg, "last-as %u", &num) == 1 && num > 0 && num < 10)
+ return (void*)(uintptr_t)num;
+
+ return route_aspath_compile(arg);
+}
+
+static void
+route_set_aspath_prepend_free (void *rule)
+{
+ if ((uintptr_t)rule > 10)
+ route_aspath_free(rule);
+}
+
+
/* Set as-path prepend rule structure. */
struct route_map_rule_cmd route_set_aspath_prepend_cmd =
{
"as-path prepend",
route_set_aspath_prepend,
- route_aspath_compile,
- route_aspath_free,
+ route_set_aspath_prepend_compile,
+ route_set_aspath_prepend_free,
};
/* `set as-path exclude ASn' */
@@ -3127,6 +3156,15 @@
return ret;
}
+ALIAS (set_aspath_prepend,
+ set_aspath_prepend_lastas_cmd,
+ "set as-path prepend (last-as) <1-10>",
+ SET_STR
+ "Transform BGP AS_PATH attribute\n"
+ "Prepend to the as-path\n"
+ "Use the peer's AS-number\n"
+ "Number of times to insert");
+
DEFUN (no_set_aspath_prepend,
no_set_aspath_prepend_cmd,
"no set as-path prepend",
@@ -3983,6 +4021,7 @@
install_element (RMAP_NODE, &no_set_metric_cmd);
install_element (RMAP_NODE, &no_set_metric_val_cmd);
install_element (RMAP_NODE, &set_aspath_prepend_cmd);
+ install_element (RMAP_NODE, &set_aspath_prepend_lastas_cmd);
install_element (RMAP_NODE, &set_aspath_exclude_cmd);
install_element (RMAP_NODE, &no_set_aspath_prepend_cmd);
install_element (RMAP_NODE, &no_set_aspath_prepend_val_cmd);