unix_diag: Unix socket name NLA

Report the sun_path when requested as NLA. With leading '\0' if
present but without the leading AF_UNIX bits.

Signed-off-by: Pavel Emelyanov <xemul@parallels.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

include/linux/unix_diag.h

@@ -11,6 +11,8 @@ struct unix_diag_req {
 	__u32	udiag_cookie[2];
 };
 
+#define UDIAG_SHOW_NAME		0x00000001	/* show name (not path) */
+
 struct unix_diag_msg {
 	__u8	udiag_family;
 	__u8	udiag_type;
@@ -21,4 +23,10 @@ struct unix_diag_msg {
 	__u32	udiag_cookie[2];
 };
 
+enum {
+	UNIX_DIAG_NAME,
+
+	UNIX_DIAG_MAX,
+};
+
 #endif