net/ncsi: Extend NC-SI Netlink interface to allow user space to send NC-SI command

The new command (NCSI_CMD_SEND_CMD) is added to allow user space application
to send NC-SI command to the network card.
Also, add a new attribute (NCSI_ATTR_DATA) for transferring request and response.

The work flow is as below.

Request:
User space application
	-> Netlink interface (msg)
	-> new Netlink handler - ncsi_send_cmd_nl()
	-> ncsi_xmit_cmd()

Response:
Response received - ncsi_rcv_rsp()
	-> internal response handler - ncsi_rsp_handler_xxx()
	-> ncsi_rsp_handler_netlink()
	-> ncsi_send_netlink_rsp ()
	-> Netlink interface (msg)
	-> user space application

Command timeout - ncsi_request_timeout()
	-> ncsi_send_netlink_timeout ()
	-> Netlink interface (msg with zero data length)
	-> user space application

Error:
Error detected
	-> ncsi_send_netlink_err ()
	-> Netlink interface (err msg)
	-> user space application

Signed-off-by: Justin Lee <justin.lee1@dell.com>
Reviewed-by: Samuel Mendoza-Jonas <sam@mendozajonas.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/ncsi/ncsi-netlink.h b/net/ncsi/ncsi-netlink.h
index 91a5c25..c4a4688 100644
--- a/net/ncsi/ncsi-netlink.h
+++ b/net/ncsi/ncsi-netlink.h
@@ -14,6 +14,18 @@
 
 #include "internal.h"
 
+int ncsi_send_netlink_rsp(struct ncsi_request *nr,
+			  struct ncsi_package *np,
+			  struct ncsi_channel *nc);
+int ncsi_send_netlink_timeout(struct ncsi_request *nr,
+			      struct ncsi_package *np,
+			      struct ncsi_channel *nc);
+int ncsi_send_netlink_err(struct net_device *dev,
+			  u32 snd_seq,
+			  u32 snd_portid,
+			  struct nlmsghdr *nlhdr,
+			  int err);
+
 int ncsi_init_netlink(struct net_device *dev);
 int ncsi_unregister_netlink(struct net_device *dev);