net: Add support for filtering neigh dump by master device

Add support for filtering neighbor dumps by master device by adding
the NDA_MASTER attribute to the dump request. A new netlink flag,
NLM_F_DUMP_FILTERED, is added to indicate the kernel supports the
request and output is filtered as requested.

Signed-off-by: David Ahern <dsa@cumulusnetworks.com>
Acked-by: Roopa Prabhu <roopa@cumulusnetworks.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/include/uapi/linux/netlink.h b/include/uapi/linux/netlink.h
index 6f3fe16..f095155 100644
--- a/include/uapi/linux/netlink.h
+++ b/include/uapi/linux/netlink.h
@@ -54,6 +54,7 @@
 #define NLM_F_ACK		4	/* Reply with ack, with zero or error code */
 #define NLM_F_ECHO		8	/* Echo this request 		*/
 #define NLM_F_DUMP_INTR		16	/* Dump was inconsistent due to sequence change */
+#define NLM_F_DUMP_FILTERED	32	/* Dump was filtered as requested */
 
 /* Modifiers to GET request */
 #define NLM_F_ROOT	0x100	/* specify tree	root	*/