From 1dc02a55bc5ddb1e30e366f1326d2e73e1b8db61 Mon Sep 17 00:00:00 2001
From: Naveen Thanikachalam <nthanikachal@vmware.com>
Date: Wed, 8 May 2019 02:58:27 -0700
Subject: [PATCH] lib, bgpd: Disallow processing of duplicate config.

This fix aims to reduce the load on BGPD when certain
exisiting configurations are replayed.
Specifically, the fix prevents BGPD from processing
routes when the following already existing configurations
are replayed:
1) A match criteria is configured within a route-map.
2) When "call" is invoked within a route-map.
3) When a route-map is tied to a BGP neighbor.

Signed-off-by: NaveenThanikachalam <nthanikachal@vmware.com>
---
 bgpd/bgpd.c    |  9 ++++++++-
 lib/routemap.c | 17 +++++++++++++++++
 2 files changed, 25 insertions(+), 1 deletion(-)

diff --git a/bgpd/bgpd.c b/bgpd/bgpd.c
index b2925cd512..6183bbd471 100644
--- a/bgpd/bgpd.c
+++ b/bgpd/bgpd.c
@@ -6186,8 +6186,15 @@ int peer_route_map_set(struct peer *peer, afi_t afi, safi_t safi, int direct,
 
 	/* Set configuration on peer. */
 	filter = &peer->filter[afi][safi];
-	if (filter->map[direct].name)
+	if (filter->map[direct].name) {
+		/* If the neighbor is configured with the same route-map
+		 * again then, ignore the duplicate configuration.
+		 */
+		if (strcmp(filter->map[direct].name, name) == 0)
+			return 0;
+
 		XFREE(MTYPE_BGP_FILTER_NAME, filter->map[direct].name);
+	}
 	route_map_counter_decrement(filter->map[direct].map);
 	filter->map[direct].name = XSTRDUP(MTYPE_BGP_FILTER_NAME, name);
 	filter->map[direct].map = route_map;
diff --git a/lib/routemap.c b/lib/routemap.c
index 5cfcf6651d..e8bdaa68fb 100644
--- a/lib/routemap.c
+++ b/lib/routemap.c
@@ -1308,6 +1308,16 @@ int route_map_add_match(struct route_map_index *index, const char *match_name,
 	for (rule = index->match_list.head; rule; rule = next) {
 		next = rule->next;
 		if (rule->cmd == cmd) {
+			/* If the configured route-map match rule is exactly
+			 * the same as the existing configuration then,
+			 * ignore the duplicate configuration.
+			 */
+			if (strcmp(match_arg, rule->rule_str) == 0) {
+				if (cmd->func_free)
+					(*cmd->func_free)(compile);
+				return RMAP_COMPILE_SUCCESS;
+			}
+
 			route_map_rule_delete(&index->match_list, rule);
 			replaced = 1;
 		}
@@ -2805,6 +2815,13 @@ DEFUN (rmap_call,
 
 	assert(index);
 
+	/* If "call" is invoked with the same route-map name as
+	 * the one previously configured then, ignore the duplicate
+	 * configuration.
+	 */
+	if (index->nextrm && (strcmp(index->nextrm, rmap) == 0))
+		return CMD_SUCCESS;
+
 	if (index->nextrm) {
 		route_map_upd8_dependency(RMAP_EVENT_CALL_DELETED,
 					  index->nextrm, index->map->name);