Bluetooth: EWS: support extended seq numbers

Adds support for extended sequence numbers found in
extended control fields.
Signed-off-by: Andrei Emeltchenko <andrei.emeltchenko@intel.com>
Signed-off-by: Gustavo F. Padovan <padovan@profusion.mobi>

include/net/bluetooth/bluetooth.h

@@ -158,7 +158,7 @@ struct bt_skb_cb {
 	__u8 pkt_type;
 	__u8 incoming;
 	__u16 expect;
-	__u8 tx_seq;
+	__u16 tx_seq;
 	__u8 retries;
 	__u8 sar;
 	unsigned short channel;

include/net/bluetooth/l2cap.h

@@ -381,6 +381,7 @@ struct l2cap_chan {
 	__u8		fcs;
 
 	__u16		tx_win;
+	__u16		tx_win_max;
 	__u8		max_tx;
 	__u16		retrans_timeout;
 	__u16		monitor_timeout;
@@ -543,6 +544,22 @@ enum {
 		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;

net/bluetooth/l2cap_core.c

@@ -1295,7 +1295,7 @@ static void l2cap_streaming_send(struct l2cap_chan *chan)
 
 		l2cap_do_send(chan, skb);
 
-		chan->next_tx_seq = (chan->next_tx_seq + 1) % 64;
+		chan->next_tx_seq = __next_seq(chan, chan->next_tx_seq);
 	}
 }
 
@@ -1389,7 +1389,8 @@ static int l2cap_ertm_send(struct l2cap_chan *chan)
 		__set_retrans_timer(chan);
 
 		bt_cb(skb)->tx_seq = chan->next_tx_seq;
-		chan->next_tx_seq = (chan->next_tx_seq + 1) % 64;
+
+		chan->next_tx_seq = __next_seq(chan, chan->next_tx_seq);
 
 		if (bt_cb(skb)->retries == 1)
 			chan->unacked_frames++;
@@ -1967,12 +1968,15 @@ static inline bool __l2cap_efs_supported(struct l2cap_chan *chan)
 static inline void l2cap_txwin_setup(struct l2cap_chan *chan)
 {
 	if (chan->tx_win > L2CAP_DEFAULT_TX_WINDOW &&
-						__l2cap_ews_supported(chan))
+						__l2cap_ews_supported(chan)) {
 		/* use extended control field */
 		set_bit(FLAG_EXT_CTRL, &chan->flags);
-	else
+		chan->tx_win_max = L2CAP_DEFAULT_EXT_WINDOW;
+	} else {
 		chan->tx_win = min_t(u16, chan->tx_win,
 						L2CAP_DEFAULT_TX_WINDOW);
+		chan->tx_win_max = L2CAP_DEFAULT_TX_WINDOW;
+	}
 }
 
 static int l2cap_build_conf_req(struct l2cap_chan *chan, void *data)
@@ -2138,6 +2142,7 @@ static int l2cap_parse_conf_req(struct l2cap_chan *chan, void *data)
 
 			set_bit(FLAG_EXT_CTRL, &chan->flags);
 			set_bit(CONF_EWS_RECV, &chan->conf_state);
+			chan->tx_win_max = L2CAP_DEFAULT_EXT_WINDOW;
 			chan->remote_tx_win = val;
 			break;
 
@@ -3225,18 +3230,14 @@ static int l2cap_add_to_srej_queue(struct l2cap_chan *chan, struct sk_buff *skb,
 		return 0;
 	}
 
-	tx_seq_offset = (tx_seq - chan->buffer_seq) % 64;
-	if (tx_seq_offset < 0)
-		tx_seq_offset += 64;
+	tx_seq_offset = __seq_offset(chan, tx_seq, chan->buffer_seq);
 
 	do {
 		if (bt_cb(next_skb)->tx_seq == tx_seq)
 			return -EINVAL;
 
-		next_tx_seq_offset = (bt_cb(next_skb)->tx_seq -
-						chan->buffer_seq) % 64;
-		if (next_tx_seq_offset < 0)
-			next_tx_seq_offset += 64;
+		next_tx_seq_offset = __seq_offset(chan,
+				bt_cb(next_skb)->tx_seq, chan->buffer_seq);
 
 		if (next_tx_seq_offset > tx_seq_offset) {
 			__skb_queue_before(&chan->srej_q, next_skb, skb);
@@ -3426,9 +3427,8 @@ static void l2cap_check_srej_gap(struct l2cap_chan *chan, u16 tx_seq)
 			break;
 		}
 
-		chan->buffer_seq_srej =
-			(chan->buffer_seq_srej + 1) % 64;
-		tx_seq = (tx_seq + 1) % 64;
+		chan->buffer_seq_srej = __next_seq(chan, chan->buffer_seq_srej);
+		tx_seq = __next_seq(chan, tx_seq);
 	}
 }
 
@@ -3463,10 +3463,13 @@ static void l2cap_send_srejframe(struct l2cap_chan *chan, u16 tx_seq)
 
 		new = kzalloc(sizeof(struct srej_list), GFP_ATOMIC);
 		new->tx_seq = chan->expected_tx_seq;
-		chan->expected_tx_seq = (chan->expected_tx_seq + 1) % 64;
+
+		chan->expected_tx_seq = __next_seq(chan, chan->expected_tx_seq);
+
 		list_add_tail(&new->list, &chan->srej_l);
 	}
-	chan->expected_tx_seq = (chan->expected_tx_seq + 1) % 64;
+
+	chan->expected_tx_seq = __next_seq(chan, chan->expected_tx_seq);
 }
 
 static inline int l2cap_data_channel_iframe(struct l2cap_chan *chan, u32 rx_control, struct sk_buff *skb)
@@ -3492,9 +3495,7 @@ static inline int l2cap_data_channel_iframe(struct l2cap_chan *chan, u32 rx_cont
 	chan->expected_ack_seq = req_seq;
 	l2cap_drop_acked_frames(chan);
 
-	tx_seq_offset = (tx_seq - chan->buffer_seq) % 64;
-	if (tx_seq_offset < 0)
-		tx_seq_offset += 64;
+	tx_seq_offset = __seq_offset(chan, tx_seq, chan->buffer_seq);
 
 	/* invalid tx_seq */
 	if (tx_seq_offset >= chan->tx_win) {
@@ -3542,10 +3543,8 @@ static inline int l2cap_data_channel_iframe(struct l2cap_chan *chan, u32 rx_cont
 			l2cap_send_srejframe(chan, tx_seq);
 		}
 	} else {
-		expected_tx_seq_offset =
-			(chan->expected_tx_seq - chan->buffer_seq) % 64;
-		if (expected_tx_seq_offset < 0)
-			expected_tx_seq_offset += 64;
+		expected_tx_seq_offset = __seq_offset(chan,
+				chan->expected_tx_seq, chan->buffer_seq);
 
 		/* duplicated tx_seq */
 		if (tx_seq_offset < expected_tx_seq_offset)
@@ -3570,7 +3569,7 @@ static inline int l2cap_data_channel_iframe(struct l2cap_chan *chan, u32 rx_cont
 	return 0;
 
 expected:
-	chan->expected_tx_seq = (chan->expected_tx_seq + 1) % 64;
+	chan->expected_tx_seq = __next_seq(chan, chan->expected_tx_seq);
 
 	if (test_bit(CONN_SREJ_SENT, &chan->conn_state)) {
 		bt_cb(skb)->tx_seq = tx_seq;
@@ -3580,7 +3579,8 @@ static inline int l2cap_data_channel_iframe(struct l2cap_chan *chan, u32 rx_cont
 	}
 
 	err = l2cap_reassemble_sdu(chan, skb, rx_control);
-	chan->buffer_seq = (chan->buffer_seq + 1) % 64;
+	chan->buffer_seq = __next_seq(chan, chan->buffer_seq);
+
 	if (err < 0) {
 		l2cap_send_disconn_req(chan->conn, chan, ECONNRESET);
 		return err;
@@ -3794,14 +3794,11 @@ static int l2cap_ertm_data_rcv(struct sock *sk, struct sk_buff *skb)
 	}
 
 	req_seq = __get_reqseq(chan, control);
-	req_seq_offset = (req_seq - chan->expected_ack_seq) % 64;
-	if (req_seq_offset < 0)
-		req_seq_offset += 64;
 
-	next_tx_seq_offset =
-		(chan->next_tx_seq - chan->expected_ack_seq) % 64;
-	if (next_tx_seq_offset < 0)
-		next_tx_seq_offset += 64;
+	req_seq_offset = __seq_offset(chan, req_seq, chan->expected_ack_seq);
+
+	next_tx_seq_offset = __seq_offset(chan, chan->next_tx_seq,
+						chan->expected_ack_seq);
 
 	/* check for invalid req-seq */
 	if (req_seq_offset > next_tx_seq_offset) {
@@ -3907,7 +3904,7 @@ static inline int l2cap_data_channel(struct l2cap_conn *conn, u16 cid, struct sk
 			/* TODO: Notify userland of missing data */
 		}
 
-		chan->expected_tx_seq = (tx_seq + 1) % 64;
+		chan->expected_tx_seq = __next_seq(chan, tx_seq);
 
 		if (l2cap_reassemble_sdu(chan, skb, control) == -EMSGSIZE)
 			l2cap_send_disconn_req(chan->conn, chan, ECONNRESET);