rtnl: Add support for netdev event to link messages

When netdev events happen, a rtnetlink_event() handler will send
messages for every event in it's white list.  These messages contain
current information about a particular device, but they do not include
the iformation about which event just happened.  The consumer of
the message has to try to infer this information.  In some cases
(ex: NETDEV_NOTIFY_PEERS), that is not possible.

This patch adds a new extension to RTM_NEWLINK message called IFLA_EVENT
that would have an encoding of the which event triggered this
message.  This would allow the the message consumer to easily determine
if it is interested in a particular event or not.

Signed-off-by: Vladislav Yasevich <vyasevic@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

include/uapi/linux/if_link.h

@@ -157,6 +157,7 @@ enum {
 	IFLA_GSO_MAX_SIZE,
 	IFLA_PAD,
 	IFLA_XDP,
+	IFLA_EVENT,
 	__IFLA_MAX
 };
 
@@ -899,4 +900,24 @@ enum {
 
 #define IFLA_XDP_MAX (__IFLA_XDP_MAX - 1)
 
+enum {
+	IFLA_EVENT_UNSPEC,
+	IFLA_EVENT_REBOOT,
+	IFLA_EVENT_CHANGE_MTU,
+	IFLA_EVENT_CHANGE_ADDR,
+	IFLA_EVENT_CHANGE_NAME,
+	IFLA_EVENT_FEAT_CHANGE,
+	IFLA_EVENT_BONDING_FAILOVER,
+	IFLA_EVENT_POST_TYPE_CHANGE,
+	IFLA_EVENT_NOTIFY_PEERS,
+	IFLA_EVENT_CHANGE_UPPER,
+	IFLA_EVENT_RESEND_IGMP,
+	IFLA_EVENT_PRE_CHANGE_MTU,
+	IFLA_EVENT_CHANGE_INFO_DATA,
+	IFLA_EVENT_PRE_CHANGE_UPPER,
+	IFLA_EVENT_CHANGE_LOWER_STATE,
+	IFLA_EVENT_UDP_TUNNEL_PUSH_INFO,
+	IFLA_EVENT_CHANGE_TX_QUEUE_LEN,
+};
+
 #endif /* _UAPI_LINUX_IF_LINK_H */