From 8cfa1e78463844518bb95d59fee2da440bbd208e Mon Sep 17 00:00:00 2001
From: Donatas Abraitis <donatas@opensourcerouting.org>
Date: Thu, 26 May 2022 20:15:35 +0300
Subject: [PATCH] bgpd: Simplify BGP community alias handling

Also, warn in CLI an operator if we are trying to overwrite an existing
community alias with an existing alias.

Signed-off-by: Donatas Abraitis <donatas@opensourcerouting.org>
---
 bgpd/bgp_vty.c | 46 ++++++++++++++++++++++++++++------------------
 1 file changed, 28 insertions(+), 18 deletions(-)

diff --git a/bgpd/bgp_vty.c b/bgpd/bgp_vty.c
index c013160d95..0a4083e5f6 100644
--- a/bgpd/bgp_vty.c
+++ b/bgpd/bgp_vty.c
@@ -1640,8 +1640,7 @@ DEFPY(bgp_community_alias, bgp_community_alias_cmd,
       "Community (AA:BB or AA:BB:CC)\n"
       "Alias name\n")
 {
-	struct community_alias ca1;
-	struct community_alias ca2;
+	struct community_alias ca = {};
 	struct community_alias *lookup_community;
 	struct community_alias *lookup_alias;
 	struct community *comm;
@@ -1663,39 +1662,50 @@ DEFPY(bgp_community_alias, bgp_community_alias_cmd,
 		return CMD_WARNING;
 	}
 
-	memset(&ca1, 0, sizeof(ca1));
-	memset(&ca2, 0, sizeof(ca2));
-	strlcpy(ca1.community, community, sizeof(ca1.community));
-	strlcpy(ca1.alias, alias_name, sizeof(ca1.alias));
+	strlcpy(ca.community, community, sizeof(ca.community));
+	strlcpy(ca.alias, alias_name, sizeof(ca.alias));
 
-	lookup_community = bgp_ca_community_lookup(&ca1);
-	lookup_alias = bgp_ca_alias_lookup(&ca1);
+	lookup_community = bgp_ca_community_lookup(&ca);
+	lookup_alias = bgp_ca_alias_lookup(&ca);
 
 	if (no) {
-		bgp_ca_alias_delete(&ca1);
-		bgp_ca_community_delete(&ca1);
+		bgp_ca_alias_delete(&ca);
+		bgp_ca_community_delete(&ca);
 	} else {
 		if (lookup_alias) {
 			/* Lookup if community hash table has an item
 			 * with the same alias name.
 			 */
-			strlcpy(ca2.community, lookup_alias->community,
-				sizeof(ca2.community));
-			if (bgp_ca_community_lookup(&ca2)) {
+			strlcpy(ca.community, lookup_alias->community,
+				sizeof(ca.community));
+			if (bgp_ca_community_lookup(&ca)) {
 				vty_out(vty,
 					"community (%s) already has this alias (%s)\n",
 					lookup_alias->community,
 					lookup_alias->alias);
 				return CMD_WARNING;
 			}
-			bgp_ca_alias_delete(&ca1);
+			bgp_ca_alias_delete(&ca);
 		}
 
-		if (lookup_community)
-			bgp_ca_community_delete(&ca1);
+		if (lookup_community) {
+			/* Lookup if alias hash table has an item
+			 * with the same community.
+			 */
+			strlcpy(ca.alias, lookup_community->alias,
+				sizeof(ca.alias));
+			if (bgp_ca_alias_lookup(&ca)) {
+				vty_out(vty,
+					"alias (%s) already has this community (%s)\n",
+					lookup_community->alias,
+					lookup_community->community);
+				return CMD_WARNING;
+			}
+			bgp_ca_community_delete(&ca);
+		}
 
-		bgp_ca_alias_insert(&ca1);
-		bgp_ca_community_insert(&ca1);
+		bgp_ca_alias_insert(&ca);
+		bgp_ca_community_insert(&ca);
 	}
 
 	return CMD_SUCCESS;