bridge: netlink: export port's designated cost and port

Add IFLA_BRPORT_DESIGNATED_(COST|PORT) to allow getting the port's
designated cost and port respectively via netlink.
Signed-off-by: Nikolay Aleksandrov <nikolay@cumulusnetworks.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

include/uapi/linux/if_link.h

@@ -294,6 +294,8 @@ enum {
 	IFLA_BRPORT_PROXYARP_WIFI, /* proxy ARP for Wi-Fi */
 	IFLA_BRPORT_ROOT_ID,	/* designated root */
 	IFLA_BRPORT_BRIDGE_ID,	/* designated bridge */
+	IFLA_BRPORT_DESIGNATED_PORT,
+	IFLA_BRPORT_DESIGNATED_COST,
 	__IFLA_BRPORT_MAX
 };
 #define IFLA_BRPORT_MAX (__IFLA_BRPORT_MAX - 1)

net/bridge/br_netlink.c

@@ -129,6 +129,8 @@ static inline size_t br_port_info_size(void)
 		+ nla_total_size(1)	/* IFLA_BRPORT_PROXYARP_WIFI */
 		+ nla_total_size(sizeof(struct ifla_bridge_id))	/* IFLA_BRPORT_ROOT_ID */
 		+ nla_total_size(sizeof(struct ifla_bridge_id))	/* IFLA_BRPORT_BRIDGE_ID */
+		+ nla_total_size(sizeof(u16))	/* IFLA_BRPORT_DESIGNATED_PORT */
+		+ nla_total_size(sizeof(u16))	/* IFLA_BRPORT_DESIGNATED_COST */
 		+ 0;
 }
 
@@ -166,7 +168,9 @@ static int br_port_fill_attrs(struct sk_buff *skb,
 	    nla_put(skb, IFLA_BRPORT_ROOT_ID, sizeof(struct ifla_bridge_id),
 		    &p->designated_root) ||
 	    nla_put(skb, IFLA_BRPORT_BRIDGE_ID, sizeof(struct ifla_bridge_id),
-		    &p->designated_bridge))
+		    &p->designated_bridge) ||
+	    nla_put_u16(skb, IFLA_BRPORT_DESIGNATED_PORT, p->designated_port) ||
+	    nla_put_u16(skb, IFLA_BRPORT_DESIGNATED_COST, p->designated_cost))
 		return -EMSGSIZE;
 
 	return 0;