psample: Add additional metadata attributes

Extend psample to report the following attributes when available:

* Output traffic class as a 16-bit value
* Output traffic class occupancy in bytes as a 64-bit value
* End-to-end latency of the packet in nanoseconds resolution
* Software timestamp in nanoseconds resolution (always available)
* Packet's protocol. Needed for packet dissection in user space (always
  available)

Signed-off-by: Ido Schimmel <idosch@nvidia.com>
Reviewed-by: Jiri Pirko <jiri@nvidia.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

include/uapi/linux/psample.h

@@ -16,6 +16,13 @@ enum {
 	/* commands attributes */
 	PSAMPLE_ATTR_GROUP_REFCOUNT,
 
+	PSAMPLE_ATTR_PAD,
+	PSAMPLE_ATTR_OUT_TC,		/* u16 */
+	PSAMPLE_ATTR_OUT_TC_OCC,	/* u64, bytes */
+	PSAMPLE_ATTR_LATENCY,		/* u64, nanoseconds */
+	PSAMPLE_ATTR_TIMESTAMP,		/* u64, nanoseconds */
+	PSAMPLE_ATTR_PROTO,		/* u16 */
+
 	__PSAMPLE_ATTR_MAX
 };