[RFC 1/2] Bluetooth: Header changes for ERTM state machine replacement

[Mat Martineau <mathewm@codeaurora.org>]

This change affects data structures storing ERTM state and control
fields, and adds new definitions for states and events.  An
l2cap_seq_list structure is added for tracking ERTM sequence numbers
without repeated memory allocations.  Control fields are carried in
the bt_skb_cb struct rather than constantly doing shift and mask
operations.

Signed-off-by: Mat Martineau <mathewm@codeaurora.org>
---
 include/net/bluetooth/bluetooth.h |   14 ++-
 include/net/bluetooth/l2cap.h     |  260 +++++++++----------------------------
 2 files changed, 73 insertions(+), 201 deletions(-)

diff --git a/include/net/bluetooth/bluetooth.h b/include/net/bluetooth/bluetooth.h
index 262ebd1..a667cb8 100644
--- a/include/net/bluetooth/bluetooth.h
+++ b/include/net/bluetooth/bluetooth.h
@@ -215,14 +215,24 @@ void bt_accept_unlink(struct sock *sk);
 struct sock *bt_accept_dequeue(struct sock *parent, struct socket *newsock);
 
 /* Skb helpers */
+struct bt_l2cap_control {
+	__u8  frame_type;
+	__u8  final;
+	__u8  sar;
+	__u8  super;
+	__u16 reqseq;
+	__u16 txseq;
+	__u8  poll;
+	__u8  fcs;
+};
+
 struct bt_skb_cb {
 	__u8 pkt_type;
 	__u8 incoming;
 	__u16 expect;
-	__u16 tx_seq;
 	__u8 retries;
-	__u8 sar;
 	__u8 force_active;
+	struct bt_l2cap_control control;
 };
 #define bt_cb(skb) ((struct bt_skb_cb *)((skb)->cb))
 
diff --git a/include/net/bluetooth/l2cap.h b/include/net/bluetooth/l2cap.h
index d6d8ec8..a499b60 100644
--- a/include/net/bluetooth/l2cap.h
+++ b/include/net/bluetooth/l2cap.h
@@ -3,6 +3,7 @@
    Copyright (C) 2000-2001 Qualcomm Incorporated
    Copyright (C) 2009-2010 Gustavo F. Padovan <gustavo@padovan.org>
    Copyright (C) 2010 Google Inc.
+   Copyright (c) 2012 Code Aurora Forum.  All rights reserved.
 
    Written 2000,2001 by Maxim Krasnyansky <maxk@qualcomm.com>
 
@@ -44,6 +45,9 @@
 #define L2CAP_DEFAULT_MAX_SDU_SIZE	0xFFFF
 #define L2CAP_DEFAULT_SDU_ITIME		0xFFFFFFFF
 #define L2CAP_DEFAULT_ACC_LAT		0xFFFFFFFF
+#define L2CAP_BREDR_MAX_PAYLOAD		1019    /* 3-DH5 packet */
+#define L2CAP_MAX_ERTM_QUEUED		5
+#define L2CAP_MIN_ERTM_QUEUED		2
 
 #define L2CAP_DISC_TIMEOUT             (100)
 #define L2CAP_DISC_REJ_TIMEOUT         (5000)  /*  5 seconds */
@@ -139,6 +143,8 @@ struct l2cap_conninfo {
 
 #define L2CAP_CTRL_TXSEQ_SHIFT		1
 #define L2CAP_CTRL_SUPER_SHIFT		2
+#define L2CAP_CTRL_POLL_SHIFT		4
+#define L2CAP_CTRL_FINAL_SHIFT		7
 #define L2CAP_CTRL_REQSEQ_SHIFT		8
 #define L2CAP_CTRL_SAR_SHIFT		14
 
@@ -152,9 +158,11 @@ struct l2cap_conninfo {
 #define L2CAP_EXT_CTRL_FINAL		0x00000002
 #define L2CAP_EXT_CTRL_FRAME_TYPE	0x00000001 /* I- or S-Frame */
 
+#define L2CAP_EXT_CTRL_FINAL_SHIFT	1
 #define L2CAP_EXT_CTRL_REQSEQ_SHIFT	2
 #define L2CAP_EXT_CTRL_SAR_SHIFT	16
 #define L2CAP_EXT_CTRL_SUPER_SHIFT	16
+#define L2CAP_EXT_CTRL_POLL_SHIFT	18
 #define L2CAP_EXT_CTRL_TXSEQ_SHIFT	18
 
 /* L2CAP Supervisory Function */
@@ -186,6 +194,8 @@ struct l2cap_hdr {
 #define L2CAP_FCS_SIZE		2
 #define L2CAP_SDULEN_SIZE	2
 #define L2CAP_PSMLEN_SIZE	2
+#define L2CAP_ENH_CTRL_SIZE	2
+#define L2CAP_EXT_CTRL_SIZE	4
 
 struct l2cap_cmd_hdr {
 	__u8       code;
@@ -401,9 +411,12 @@ struct l2cap_conn_param_update_rsp {
 #define L2CAP_CONN_PARAM_REJECTED	0x0001
 
 /* ----- L2CAP channels and connections ----- */
-struct srej_list {
-	__u16	tx_seq;
-	struct list_head list;
+struct l2cap_seq_list {
+	__u16 head;
+	__u16 tail;
+	__u16 size;
+	__u16 mask;
+	__u16 *list;
 };
 
 struct l2cap_chan {
@@ -446,6 +459,9 @@ struct l2cap_chan {
 	__u16		monitor_timeout;
 	__u16		mps;
 
+	__u8		tx_state;
+	__u8		rx_state;
+
 	unsigned long	conf_state;
 	unsigned long	conn_state;
 	unsigned long	flags;
@@ -454,15 +470,16 @@ struct l2cap_chan {
 	__u16		expected_ack_seq;
 	__u16		expected_tx_seq;
 	__u16		buffer_seq;
-	__u16		buffer_seq_srej;
 	__u16		srej_save_reqseq;
+	__u16		last_acked_seq;
 	__u16		frames_sent;
 	__u16		unacked_frames;
 	__u8		retry_count;
-	__u8		num_acked;
+	__u16		srej_queue_next;
 	__u16		sdu_len;
 	struct sk_buff	*sdu;
 	struct sk_buff	*sdu_last_frag;
+	atomic_t	ertm_queued;
 
 	__u16		remote_tx_win;
 	__u8		remote_max_tx;
@@ -486,11 +503,13 @@ struct l2cap_chan {
 	struct delayed_work	retrans_timer;
 	struct delayed_work	monitor_timer;
 	struct delayed_work	ack_timer;
+	struct work_struct	tx_work;
 
 	struct sk_buff		*tx_send_head;
 	struct sk_buff_head	tx_q;
 	struct sk_buff_head	srej_q;
-	struct list_head	srej_l;
+	struct l2cap_seq_list	srej_list;
+	struct l2cap_seq_list	retrans_list;
 
 	struct list_head list;
 	struct list_head global_l;
@@ -645,200 +664,43 @@ static inline bool l2cap_clear_timer(struct l2cap_chan *chan,
 
 #define __set_chan_timer(c, t) l2cap_set_timer(c, &c->chan_timer, (t))
 #define __clear_chan_timer(c) l2cap_clear_timer(c, &c->chan_timer)
-#define __set_retrans_timer(c) l2cap_set_timer(c, &c->retrans_timer, \
-		msecs_to_jiffies(L2CAP_DEFAULT_RETRANS_TO));
-#define __clear_retrans_timer(c) l2cap_clear_timer(c, &c->retrans_timer)
-#define __set_monitor_timer(c) l2cap_set_timer(c, &c->monitor_timer, \
-		msecs_to_jiffies(L2CAP_DEFAULT_MONITOR_TO));
-#define __clear_monitor_timer(c) l2cap_clear_timer(c, &c->monitor_timer)
-#define __set_ack_timer(c) l2cap_set_timer(c, &chan->ack_timer, \
-		msecs_to_jiffies(L2CAP_DEFAULT_ACK_TO));
-#define __clear_ack_timer(c) l2cap_clear_timer(c, &c->ack_timer)
-
-static inline int __seq_offset(struct l2cap_chan *chan, __u16 seq1, __u16 seq2)
-{
-	int offset;
-
-	offset = (seq1 - seq2) % (chan->tx_win_max + 1);
-	if (offset < 0)
-		offset += (chan->tx_win_max + 1);
-
-	return offset;
-}
-
-static inline __u16 __next_seq(struct l2cap_chan *chan, __u16 seq)
-{
-	return (seq + 1) % (chan->tx_win_max + 1);
-}
-
-static inline int l2cap_tx_window_full(struct l2cap_chan *ch)
-{
-	int sub;
-
-	sub = (ch->next_tx_seq - ch->expected_ack_seq) % 64;
-
-	if (sub < 0)
-		sub += 64;
-
-	return sub == ch->remote_tx_win;
-}
-
-static inline __u16 __get_reqseq(struct l2cap_chan *chan, __u32 ctrl)
-{
-	if (test_bit(FLAG_EXT_CTRL, &chan->flags))
-		return (ctrl & L2CAP_EXT_CTRL_REQSEQ) >>
-						L2CAP_EXT_CTRL_REQSEQ_SHIFT;
-	else
-		return (ctrl & L2CAP_CTRL_REQSEQ) >> L2CAP_CTRL_REQSEQ_SHIFT;
-}
-
-static inline __u32 __set_reqseq(struct l2cap_chan *chan, __u32 reqseq)
-{
-	if (test_bit(FLAG_EXT_CTRL, &chan->flags))
-		return (reqseq << L2CAP_EXT_CTRL_REQSEQ_SHIFT) &
-							L2CAP_EXT_CTRL_REQSEQ;
-	else
-		return (reqseq << L2CAP_CTRL_REQSEQ_SHIFT) & L2CAP_CTRL_REQSEQ;
-}
-
-static inline __u16 __get_txseq(struct l2cap_chan *chan, __u32 ctrl)
-{
-	if (test_bit(FLAG_EXT_CTRL, &chan->flags))
-		return (ctrl & L2CAP_EXT_CTRL_TXSEQ) >>
-						L2CAP_EXT_CTRL_TXSEQ_SHIFT;
-	else
-		return (ctrl & L2CAP_CTRL_TXSEQ) >> L2CAP_CTRL_TXSEQ_SHIFT;
-}
-
-static inline __u32 __set_txseq(struct l2cap_chan *chan, __u32 txseq)
-{
-	if (test_bit(FLAG_EXT_CTRL, &chan->flags))
-		return (txseq << L2CAP_EXT_CTRL_TXSEQ_SHIFT) &
-							L2CAP_EXT_CTRL_TXSEQ;
-	else
-		return (txseq << L2CAP_CTRL_TXSEQ_SHIFT) & L2CAP_CTRL_TXSEQ;
-}
-
-static inline bool __is_sframe(struct l2cap_chan *chan, __u32 ctrl)
-{
-	if (test_bit(FLAG_EXT_CTRL, &chan->flags))
-		return ctrl & L2CAP_EXT_CTRL_FRAME_TYPE;
-	else
-		return ctrl & L2CAP_CTRL_FRAME_TYPE;
-}
-
-static inline __u32 __set_sframe(struct l2cap_chan *chan)
-{
-	if (test_bit(FLAG_EXT_CTRL, &chan->flags))
-		return L2CAP_EXT_CTRL_FRAME_TYPE;
-	else
-		return L2CAP_CTRL_FRAME_TYPE;
-}
-
-static inline __u8 __get_ctrl_sar(struct l2cap_chan *chan, __u32 ctrl)
-{
-	if (test_bit(FLAG_EXT_CTRL, &chan->flags))
-		return (ctrl & L2CAP_EXT_CTRL_SAR) >> L2CAP_EXT_CTRL_SAR_SHIFT;
-	else
-		return (ctrl & L2CAP_CTRL_SAR) >> L2CAP_CTRL_SAR_SHIFT;
-}
 
-static inline __u32 __set_ctrl_sar(struct l2cap_chan *chan, __u32 sar)
-{
-	if (test_bit(FLAG_EXT_CTRL, &chan->flags))
-		return (sar << L2CAP_EXT_CTRL_SAR_SHIFT) & L2CAP_EXT_CTRL_SAR;
-	else
-		return (sar << L2CAP_CTRL_SAR_SHIFT) & L2CAP_CTRL_SAR;
-}
-
-static inline bool __is_sar_start(struct l2cap_chan *chan, __u32 ctrl)
-{
-	return __get_ctrl_sar(chan, ctrl) == L2CAP_SAR_START;
-}
-
-static inline __u32 __get_sar_mask(struct l2cap_chan *chan)
-{
-	if (test_bit(FLAG_EXT_CTRL, &chan->flags))
-		return L2CAP_EXT_CTRL_SAR;
-	else
-		return L2CAP_CTRL_SAR;
-}
-
-static inline __u8 __get_ctrl_super(struct l2cap_chan *chan, __u32 ctrl)
-{
-	if (test_bit(FLAG_EXT_CTRL, &chan->flags))
-		return (ctrl & L2CAP_EXT_CTRL_SUPERVISE) >>
-						L2CAP_EXT_CTRL_SUPER_SHIFT;
-	else
-		return (ctrl & L2CAP_CTRL_SUPERVISE) >> L2CAP_CTRL_SUPER_SHIFT;
-}
-
-static inline __u32 __set_ctrl_super(struct l2cap_chan *chan, __u32 super)
-{
-	if (test_bit(FLAG_EXT_CTRL, &chan->flags))
-		return (super << L2CAP_EXT_CTRL_SUPER_SHIFT) &
-						L2CAP_EXT_CTRL_SUPERVISE;
-	else
-		return (super << L2CAP_CTRL_SUPER_SHIFT) &
-							L2CAP_CTRL_SUPERVISE;
-}
-
-static inline __u32 __set_ctrl_final(struct l2cap_chan *chan)
-{
-	if (test_bit(FLAG_EXT_CTRL, &chan->flags))
-		return L2CAP_EXT_CTRL_FINAL;
-	else
-		return L2CAP_CTRL_FINAL;
-}
-
-static inline bool __is_ctrl_final(struct l2cap_chan *chan, __u32 ctrl)
-{
-	if (test_bit(FLAG_EXT_CTRL, &chan->flags))
-		return ctrl & L2CAP_EXT_CTRL_FINAL;
-	else
-		return ctrl & L2CAP_CTRL_FINAL;
-}
-
-static inline __u32 __set_ctrl_poll(struct l2cap_chan *chan)
-{
-	if (test_bit(FLAG_EXT_CTRL, &chan->flags))
-		return L2CAP_EXT_CTRL_POLL;
-	else
-		return L2CAP_CTRL_POLL;
-}
-
-static inline bool __is_ctrl_poll(struct l2cap_chan *chan, __u32 ctrl)
-{
-	if (test_bit(FLAG_EXT_CTRL, &chan->flags))
-		return ctrl & L2CAP_EXT_CTRL_POLL;
-	else
-		return ctrl & L2CAP_CTRL_POLL;
-}
-
-static inline __u32 __get_control(struct l2cap_chan *chan, void *p)
-{
-	if (test_bit(FLAG_EXT_CTRL, &chan->flags))
-		return get_unaligned_le32(p);
-	else
-		return get_unaligned_le16(p);
-}
-
-static inline void __put_control(struct l2cap_chan *chan, __u32 control,
-								void *p)
-{
-	if (test_bit(FLAG_EXT_CTRL, &chan->flags))
-		return put_unaligned_le32(control, p);
-	else
-		return put_unaligned_le16(control, p);
-}
-
-static inline __u8 __ctrl_size(struct l2cap_chan *chan)
-{
-	if (test_bit(FLAG_EXT_CTRL, &chan->flags))
-		return L2CAP_EXT_HDR_SIZE - L2CAP_HDR_SIZE;
-	else
-		return L2CAP_ENH_HDR_SIZE - L2CAP_HDR_SIZE;
-}
+#define L2CAP_SEQ_LIST_CLEAR       0xFFFF
+#define L2CAP_SEQ_LIST_TAIL        0x8000
+
+#define L2CAP_ERTM_TX_STATE_XMIT          0x01
+#define L2CAP_ERTM_TX_STATE_WAIT_F        0x02
+
+#define L2CAP_ERTM_RX_STATE_RECV                    0x01
+#define L2CAP_ERTM_RX_STATE_SREJ_SENT               0x02
+
+#define L2CAP_ERTM_TXSEQ_EXPECTED        0x00
+#define L2CAP_ERTM_TXSEQ_EXPECTED_SREJ   0x01
+#define L2CAP_ERTM_TXSEQ_UNEXPECTED      0x02
+#define L2CAP_ERTM_TXSEQ_UNEXPECTED_SREJ 0x03
+#define L2CAP_ERTM_TXSEQ_DUPLICATE       0x04
+#define L2CAP_ERTM_TXSEQ_DUPLICATE_SREJ  0x05
+#define L2CAP_ERTM_TXSEQ_INVALID         0x06
+#define L2CAP_ERTM_TXSEQ_INVALID_IGNORE  0x07
+
+#define L2CAP_ERTM_EVENT_DATA_REQUEST          0x01
+#define L2CAP_ERTM_EVENT_LOCAL_BUSY_DETECTED   0x02
+#define L2CAP_ERTM_EVENT_LOCAL_BUSY_CLEAR      0x03
+#define L2CAP_ERTM_EVENT_RECV_REQSEQ_AND_FBIT  0x04
+#define L2CAP_ERTM_EVENT_RECV_FBIT             0x05
+#define L2CAP_ERTM_EVENT_RETRANS_TIMER_EXPIRES 0x06
+#define L2CAP_ERTM_EVENT_MONITOR_TIMER_EXPIRES 0x07
+#define L2CAP_ERTM_EVENT_EXPLICIT_POLL         0x08
+#define L2CAP_ERTM_EVENT_RECV_IFRAME           0x09
+#define L2CAP_ERTM_EVENT_RECV_RR               0x0a
+#define L2CAP_ERTM_EVENT_RECV_REJ              0x0b
+#define L2CAP_ERTM_EVENT_RECV_RNR              0x0c
+#define L2CAP_ERTM_EVENT_RECV_SREJ             0x0d
+#define L2CAP_ERTM_EVENT_RECV_FRAME            0x0e
+
+#define __delta_seq(x, y, c) ((x) >= (y) ? (x) - (y) : \
+				(c)->tx_win_max + 1 - (y) + (x))
+#define __next_seq(x, c) ((x + 1) & ((c)->tx_win_max))
 
 extern bool disable_ertm;
 
-- 
1.7.9

--
Mat Martineau
Employee of Qualcomm Innovation Center, Inc.
Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum