sock_diag: allow to dump bpf filters

This patch allows to dump BPF filters attached to a socket with
SO_ATTACH_FILTER.
Note that we check CAP_SYS_ADMIN before allowing to dump this info.

For now, only AF_PACKET sockets use this feature.

Signed-off-by: Nicolas Dichtel <nicolas.dichtel@6wind.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/include/uapi/linux/packet_diag.h b/include/uapi/linux/packet_diag.h
index c0802c1..b2cc0cd 100644
--- a/include/uapi/linux/packet_diag.h
+++ b/include/uapi/linux/packet_diag.h
@@ -17,6 +17,7 @@
 #define PACKET_SHOW_RING_CFG	0x00000004 /* Rings configuration parameters */
 #define PACKET_SHOW_FANOUT	0x00000008
 #define PACKET_SHOW_MEMINFO	0x00000010
+#define PACKET_SHOW_FILTER	0x00000020
 
 struct packet_diag_msg {
 	__u8	pdiag_family;
@@ -35,6 +36,7 @@
 	PACKET_DIAG_FANOUT,
 	PACKET_DIAG_UID,
 	PACKET_DIAG_MEMINFO,
+	PACKET_DIAG_FILTER,
 
 	__PACKET_DIAG_MAX,
 };