NFC: LLCP raw socket support

This adds support for socket of type SOCK_RAW to LLCP.
sk_buff are copied and sent to raw sockets with a 2 bytes extra header:
The first byte header contains the nfc adapter index.
The second one contains flags:
- 0x01 - Direction (0=RX, 1=TX)
- 0x02-0x80 - Reserved
A raw socket has to be explicitly bound to a nfc adapter. This is achieved
by specifying the adapter index to be bound to in the dev_idx field of the
sockaddr_nfc_llcp struct passed to bind().

Signed-off-by: Thierry Escande <thierry.escande@linux.intel.com>
Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>
diff --git a/include/linux/nfc.h b/include/linux/nfc.h
index 6189f27..d908d17 100644
--- a/include/linux/nfc.h
+++ b/include/linux/nfc.h
@@ -183,4 +183,15 @@
 
 #define NFC_HEADER_SIZE 1
 
+/**
+ * Pseudo-header info for raw socket packets
+ * First byte is the adapter index
+ * Second byte contains flags
+ *  - 0x01 - Direction (0=RX, 1=TX)
+ *  - 0x02-0x80 - Reserved
+ **/
+#define NFC_LLCP_RAW_HEADER_SIZE	2
+#define NFC_LLCP_DIRECTION_RX		0x00
+#define NFC_LLCP_DIRECTION_TX		0x01
+
 #endif /*__LINUX_NFC_H */