bgpd: Ensure RMAC extended community is unique

The BGP Router MAC extended community should be unique and not occur
multiple times. In a VRF-to-VRF route-leak scenario where EVPN routes
from a source VRF are leaked into the target VRF and then injected
back into EVPN from the target VRF, the resulting route had more than
one RMAC. With this fix, the resulting route will have only the
target VRF's RMAC.

Signed-off-by: Vivek Venkatraman <[email protected]>

bgpd/bgp_evpn.c

@@ -738,7 +738,6 @@ static void build_evpn_type5_route_extcomm(struct bgp *bgp_vrf,
 					   struct attr *attr)
 {
 	struct ecommunity ecom_encap;
-	struct ecommunity ecom_rmac;
 	struct ecommunity_val eval;
 	struct ecommunity_val eval_rmac;
 	bgp_encap_types tnl_type;
@@ -772,12 +771,8 @@ static void build_evpn_type5_route_extcomm(struct bgp *bgp_vrf,
 
 	/* add the router mac extended community */
 	if (!is_zero_mac(&attr->rmac)) {
-		memset(&ecom_rmac, 0, sizeof(ecom_rmac));
 		encode_rmac_extcomm(&eval_rmac, &attr->rmac);
-		ecom_rmac.size = 1;
-		ecom_rmac.val = (uint8_t *)eval_rmac.val;
-		attr->ecommunity =
-			ecommunity_merge(attr->ecommunity, &ecom_rmac);
+		ecommunity_add_val(attr->ecommunity, &eval_rmac, true, true);
 	}
 
 	attr->flag |= ATTR_FLAG_BIT(BGP_ATTR_EXT_COMMUNITIES);
@@ -799,7 +794,6 @@ static void build_evpn_route_extcomm(struct bgpevpn *vpn, struct attr *attr,
 	struct ecommunity ecom_encap;
 	struct ecommunity ecom_sticky;
 	struct ecommunity ecom_default_gw;
-	struct ecommunity ecom_rmac;
 	struct ecommunity ecom_na;
 	struct ecommunity_val eval;
 	struct ecommunity_val eval_sticky;
@@ -853,12 +847,8 @@ static void build_evpn_route_extcomm(struct bgpevpn *vpn, struct attr *attr,
 
 	/* Add RMAC, if told to. */
 	if (add_l3_ecomm) {
-		memset(&ecom_rmac, 0, sizeof(ecom_rmac));
 		encode_rmac_extcomm(&eval_rmac, &attr->rmac);
-		ecom_rmac.size = 1;
-		ecom_rmac.val = (uint8_t *)eval_rmac.val;
-		attr->ecommunity =
-			ecommunity_merge(attr->ecommunity, &ecom_rmac);
+		ecommunity_add_val(attr->ecommunity, &eval_rmac, true, true);
 	}
 
 	/* Add default gateway, if needed. */