Bluetooth: Add support for BT_PKT_STATUS CMSG data for SCO connections

This change adds support for reporting the BT_PKT_STATUS to the socket
CMSG data to allow the implementation of a packet loss correction on
erroneous data received on the SCO socket.

The patch was partially developed by Marcel Holtmann and validated by
Hsin-yu Chao.

Signed-off-by: Alain Michaud <alainm@chromium.org>
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>

include/net/bluetooth/bluetooth.h

@@ -147,6 +147,10 @@ struct bt_voice {
 #define BT_MODE_LE_FLOWCTL	0x03
 #define BT_MODE_EXT_FLOWCTL	0x04
 
+#define BT_PKT_STATUS          16
+
+#define BT_SCM_PKT_STATUS	0x03
+
 __printf(1, 2)
 void bt_info(const char *fmt, ...);
 __printf(1, 2)
@@ -286,6 +290,7 @@ struct bt_sock {
 	struct sock *parent;
 	unsigned long flags;
 	void (*skb_msg_name)(struct sk_buff *, void *, int *);
+	void (*skb_put_cmsg)(struct sk_buff *, struct msghdr *, struct sock *);
 };
 
 enum {
@@ -335,6 +340,10 @@ struct l2cap_ctrl {
 	struct l2cap_chan *chan;
 };
 
+struct sco_ctrl {
+	u8	pkt_status;
+};
+
 struct hci_dev;
 
 typedef void (*hci_req_complete_t)(struct hci_dev *hdev, u8 status, u16 opcode);
@@ -361,6 +370,7 @@ struct bt_skb_cb {
 	u8 incoming:1;
 	union {
 		struct l2cap_ctrl l2cap;
+		struct sco_ctrl sco;
 		struct hci_ctrl hci;
 	};
 };

include/net/bluetooth/sco.h

@@ -46,4 +46,6 @@ struct sco_conninfo {
 	__u8  dev_class[3];
 };
 
+#define SCO_CMSG_PKT_STATUS	0x01
+
 #endif /* __SCO_H */