iplink: bridge: add support for IFLA_BR_MCAST_HASH_ELASTICITY

This patch implements support for the IFLA_BR_MCAST_HASH_ELASTICTITY
attribute in iproute2 so it can change the hash elasticity value.
Signed-off-by: Nikolay Aleksandrov <nikolay@cumulusnetworks.com>

ip/iplink_bridge.c

@@ -37,6 +37,7 @@ static void print_explain(FILE *f)
 		"                  [ mcast_router MULTICAST_ROUTER ]\n"
 		"                  [ mcast_query_use_ifaddr MCAST_QUERY_USE_IFADDR ]\n"
 		"                  [ mcast_querier MULTICAST_QUERIER ]\n"
+		"                  [ mcast_hash_elasticity HASH_ELASTICITY ]\n"
 		"\n"
 		"Where: VLAN_PROTOCOL := { 802.1Q | 802.1ad }\n"
 	);
@@ -178,6 +179,16 @@ static int bridge_parse_opt(struct link_util *lu, int argc, char **argv,
 				invarg("invalid mcast_querier", *argv);
 
 			addattr8(n, 1024, IFLA_BR_MCAST_QUERIER, mcast_querier);
+		} else if (matches(*argv, "mcast_hash_elasticity") == 0) {
+			__u32 mcast_hash_el;
+
+			NEXT_ARG();
+			if (get_u32(&mcast_hash_el, *argv, 0))
+				invarg("invalid mcast_hash_elasticity",
+				       *argv);
+
+			addattr32(n, 1024, IFLA_BR_MCAST_HASH_ELASTICITY,
+				  mcast_hash_el);
 		} else if (matches(*argv, "help") == 0) {
 			explain();
 			return -1;
@@ -331,6 +342,10 @@ static void bridge_print_opt(struct link_util *lu, FILE *f, struct rtattr *tb[])
 	if (tb[IFLA_BR_MCAST_QUERIER])
 		fprintf(f, "mcast_querier %u ",
 			rta_getattr_u8(tb[IFLA_BR_MCAST_QUERIER]));
+
+	if (tb[IFLA_BR_MCAST_HASH_ELASTICITY])
+		fprintf(f, "mcast_hash_elasticity %u ",
+			rta_getattr_u32(tb[IFLA_BR_MCAST_HASH_ELASTICITY]));
 }
 
 static void bridge_print_help(struct link_util *lu, int argc, char **argv,