net/core: Add VF link state control

Add netlink directives and ndo entry to allow for controling
VF link, which can be in one of three states:

Auto - VF link state reflects the PF link state (default)

Up - VF link state is up, traffic from VF to VF works even if
the actual PF link is down

Down - VF link state is down, no traffic from/to this VF, can be of
use while configuring the VF

Signed-off-by: Rony Efraim <ronye@mellanox.com>
Signed-off-by: Or Gerlitz <ogerlitz@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/include/uapi/linux/if_link.h b/include/uapi/linux/if_link.h
index da05a2698..03f6170 100644
--- a/include/uapi/linux/if_link.h
+++ b/include/uapi/linux/if_link.h
@@ -338,6 +338,7 @@
 	IFLA_VF_VLAN,
 	IFLA_VF_TX_RATE,	/* TX Bandwidth Allocation */
 	IFLA_VF_SPOOFCHK,	/* Spoof Checking on/off switch */
+	IFLA_VF_LINK_STATE,	/* link state enable/disable/auto switch */
 	__IFLA_VF_MAX,
 };
 
@@ -364,6 +365,18 @@
 	__u32 setting;
 };
 
+enum {
+	IFLA_VF_LINK_STATE_AUTO,	/* link state of the uplink */
+	IFLA_VF_LINK_STATE_ENABLE,	/* link always up */
+	IFLA_VF_LINK_STATE_DISABLE,	/* link always down */
+	__IFLA_VF_LINK_STATE_MAX,
+};
+
+struct ifla_vf_link_state {
+	__u32 vf;
+	__u32 link_state;
+};
+
 /* VF ports management section
  *
  *	Nested layout of set/get msg is: