Bluetooth: Add the l2cap_seq_list structure for tracking frames

A sequence list is a data structure used to track frames that need to
be retransmitted, and frames that have been requested for
retransmission by the remote device.  It can compactly represent a
list of sequence numbers within the ERTM transmit window.  Memory for
the list is allocated once at connection time, and common operations
in ERTM are O(1).

Signed-off-by: Mat Martineau <mathewm@codeaurora.org>
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>

1 files changed, 12 insertions, 0 deletions

diff --git a/include/net/bluetooth/l2cap.h b/include/net/bluetooth/l2cap.h
index a756c2406306..e33165476e83 100644
--- a/include/net/bluetooth/l2cap.h
+++ b/include/net/bluetooth/l2cap.h
@@ -407,6 +407,16 @@ struct l2cap_conn_param_update_rsp {
 #define L2CAP_CONN_PARAM_REJECTED       0x0001
 
 /* ----- L2CAP channels and connections ----- */
+struct l2cap_seq_list {
+        __u16   head;
+        __u16   tail;
+        __u16   mask;
+        __u16   *list;
+};
+
+#define L2CAP_SEQ_LIST_CLEAR    0xFFFF
+#define L2CAP_SEQ_LIST_TAIL     0x8000
+
 struct srej_list {
         __u16   tx_seq;
         struct list_head list;
@@ -501,6 +511,8 @@ struct l2cap_chan {
         struct sk_buff          *tx_send_head;
         struct sk_buff_head     tx_q;
         struct sk_buff_head     srej_q;
+        struct l2cap_seq_list   srej_list;
+        struct l2cap_seq_list   retrans_list;
         struct list_head        srej_l;
 
         struct list_head        list;