bridge: netlink: export per-vlan stats

Add a new LINK_XSTATS_TYPE_BRIDGE attribute and implement the
RTM_GETSTATS callbacks for IFLA_STATS_LINK_XSTATS (fill_linkxstats and
get_linkxstats_size) in order to export the per-vlan stats.
The paddings were added because soon these fields will be needed for
per-port per-vlan stats (or something else if someone beats me to it) so
avoiding at least a few more netlink attributes.

Signed-off-by: Nikolay Aleksandrov <nikolay@cumulusnetworks.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/include/uapi/linux/if_bridge.h b/include/uapi/linux/if_bridge.h
index 0536eef..397d503 100644
--- a/include/uapi/linux/if_bridge.h
+++ b/include/uapi/linux/if_bridge.h
@@ -134,6 +134,16 @@
 	__u16 vid;
 };
 
+struct bridge_vlan_xstats {
+	__u64 rx_bytes;
+	__u64 rx_packets;
+	__u64 tx_bytes;
+	__u64 tx_packets;
+	__u16 vid;
+	__u16 pad1;
+	__u32 pad2;
+};
+
 /* Bridge multicast database attributes
  * [MDBA_MDB] = {
  *     [MDBA_MDB_ENTRY] = {
@@ -233,4 +243,12 @@
 };
 #define MDBA_SET_ENTRY_MAX (__MDBA_SET_ENTRY_MAX - 1)
 
+/* Embedded inside LINK_XSTATS_TYPE_BRIDGE */
+enum {
+	BRIDGE_XSTATS_UNSPEC,
+	BRIDGE_XSTATS_VLAN,
+	__BRIDGE_XSTATS_MAX
+};
+#define BRIDGE_XSTATS_MAX (__BRIDGE_XSTATS_MAX - 1)
+
 #endif /* _UAPI_LINUX_IF_BRIDGE_H */