2 files changed, 172 insertions, 21 deletions

diff --git a/include/net/bluetooth/l2cap.h b/include/net/bluetooth/l2cap.h
index 8942c2ffc58..d0185cc04c1 100644
--- a/include/net/bluetooth/l2cap.h
+++ b/include/net/bluetooth/l2cap.h
@@ -35,6 +35,7 @@
 #define L2CAP_DEFAULT_MONITOR_TO	12000   /* 12 seconds */
 #define L2CAP_DEFAULT_MAX_PDU_SIZE	672
 #define L2CAP_DEFAULT_ACK_TO		200
+#define L2CAP_LOCAL_BUSY_TRIES		12
 
 #define L2CAP_CONN_TIMEOUT	(40000) /* 40 seconds */
 #define L2CAP_INFO_TIMEOUT	(4000)  /*  4 seconds */
@@ -294,6 +295,7 @@ struct l2cap_conn {
 #define l2cap_pi(sk) ((struct l2cap_pinfo *) sk)
 #define TX_QUEUE(sk) (&l2cap_pi(sk)->tx_queue)
 #define SREJ_QUEUE(sk) (&l2cap_pi(sk)->srej_queue)
+#define BUSY_QUEUE(sk) (&l2cap_pi(sk)->busy_queue)
 #define SREJ_LIST(sk) (&l2cap_pi(sk)->srej_l.list)
 
 struct srej_list {
@@ -356,6 +358,8 @@ struct l2cap_pinfo {
 	struct timer_list	ack_timer;
 	struct sk_buff_head	tx_queue;
 	struct sk_buff_head	srej_queue;
+	struct sk_buff_head	busy_queue;
+	struct work_struct	busy_work;
 	struct srej_list	srej_l;
 	struct l2cap_conn	*conn;
 	struct sock		*next_c;
@@ -383,6 +387,8 @@ struct l2cap_pinfo {
 #define L2CAP_CONN_LOCAL_BUSY      0x0040
 #define L2CAP_CONN_REJ_ACT         0x0080
 #define L2CAP_CONN_SEND_FBIT       0x0100
+#define L2CAP_CONN_RNR_SENT        0x0200
+#define L2CAP_CONN_SAR_RETRY       0x0400
 
 #define __mod_retrans_timer() mod_timer(&l2cap_pi(sk)->retrans_timer, \
 		jiffies +  msecs_to_jiffies(L2CAP_DEFAULT_RETRANS_TO));
diff --git a/net/bluetooth/l2cap.c b/net/bluetooth/l2cap.c
index 481cec22ef9..103e4b54a86 100644
--- a/net/bluetooth/l2cap.c
+++ b/net/bluetooth/l2cap.c
@@ -68,10 +68,14 @@ static u8 l2cap_fixed_chan[8] = { 0x02, };
 
 static const struct proto_ops l2cap_sock_ops;
 
+static struct workqueue_struct *_busy_wq;
+
 static struct bt_sock_list l2cap_sk_list = {
 	.lock = __RW_LOCK_UNLOCKED(l2cap_sk_list.lock)
 };
 
+static void l2cap_busy_work(struct work_struct *work);
+
 static void __l2cap_sock_close(struct sock *sk, int reason);
 static void l2cap_sock_close(struct sock *sk);
 static void l2cap_sock_kill(struct sock *sk);
@@ -386,9 +390,10 @@ static inline void l2cap_send_sframe(struct l2cap_pinfo *pi, u16 control)
 
 static inline void l2cap_send_rr_or_rnr(struct l2cap_pinfo *pi, u16 control)
 {
-	if (pi->conn_state & L2CAP_CONN_LOCAL_BUSY)
+	if (pi->conn_state & L2CAP_CONN_LOCAL_BUSY) {
 		control |= L2CAP_SUPER_RCV_NOT_READY;
-	else
+		pi->conn_state |= L2CAP_CONN_RNR_SENT;
+	} else
 		control |= L2CAP_SUPER_RCV_READY;
 
 	control |= pi->buffer_seq << L2CAP_CTRL_REQSEQ_SHIFT;
@@ -816,6 +821,7 @@ static void l2cap_sock_init(struct sock *sk, struct sock *parent)
 	pi->flush_to = L2CAP_DEFAULT_FLUSH_TO;
 	skb_queue_head_init(TX_QUEUE(sk));
 	skb_queue_head_init(SREJ_QUEUE(sk));
+	skb_queue_head_init(BUSY_QUEUE(sk));
 	INIT_LIST_HEAD(SREJ_LIST(sk));
 }
 
@@ -1439,6 +1445,7 @@ static void l2cap_send_ack(struct l2cap_pinfo *pi)
 
 	if (pi->conn_state & L2CAP_CONN_LOCAL_BUSY) {
 		control |= L2CAP_SUPER_RCV_NOT_READY;
+		pi->conn_state |= L2CAP_CONN_RNR_SENT;
 		l2cap_send_sframe(pi, control);
 		return;
 	} else if (l2cap_ertm_send(sk) == 0) {
@@ -2279,6 +2286,9 @@ static inline void l2cap_ertm_init(struct sock *sk)
 			l2cap_ack_timeout, (unsigned long) sk);
 
 	__skb_queue_head_init(SREJ_QUEUE(sk));
+	__skb_queue_head_init(BUSY_QUEUE(sk));
+
+	INIT_WORK(&l2cap_pi(sk)->busy_work, l2cap_busy_work);
 }
 
 static int l2cap_mode_supported(__u8 mode, __u32 feat_mask)
@@ -3046,6 +3056,7 @@ static inline int l2cap_disconnect_req(struct l2cap_conn *conn, struct l2cap_cmd
 
 	if (l2cap_pi(sk)->mode == L2CAP_MODE_ERTM) {
 		skb_queue_purge(SREJ_QUEUE(sk));
+		skb_queue_purge(BUSY_QUEUE(sk));
 		del_timer(&l2cap_pi(sk)->retrans_timer);
 		del_timer(&l2cap_pi(sk)->monitor_timer);
 		del_timer(&l2cap_pi(sk)->ack_timer);
@@ -3077,6 +3088,7 @@ static inline int l2cap_disconnect_rsp(struct l2cap_conn *conn, struct l2cap_cmd
 
 	if (l2cap_pi(sk)->mode == L2CAP_MODE_ERTM) {
 		skb_queue_purge(SREJ_QUEUE(sk));
+		skb_queue_purge(BUSY_QUEUE(sk));
 		del_timer(&l2cap_pi(sk)->retrans_timer);
 		del_timer(&l2cap_pi(sk)->monitor_timer);
 		del_timer(&l2cap_pi(sk)->ack_timer);
@@ -3287,6 +3299,7 @@ static inline void l2cap_send_i_or_rr_or_rnr(struct sock *sk)
 	if (pi->conn_state & L2CAP_CONN_LOCAL_BUSY) {
 		control |= L2CAP_SUPER_RCV_NOT_READY | L2CAP_CTRL_FINAL;
 		l2cap_send_sframe(pi, control);
+		pi->conn_state |= L2CAP_CONN_RNR_SENT;
 		pi->conn_state &= ~L2CAP_CONN_SEND_FBIT;
 	}
 
@@ -3338,7 +3351,7 @@ static int l2cap_ertm_reassembly_sdu(struct sock *sk, struct sk_buff *skb, u16 c
 {
 	struct l2cap_pinfo *pi = l2cap_pi(sk);
 	struct sk_buff *_skb;
-	int err = 0;
+	int err;
 
 	switch (control & L2CAP_CTRL_SAR) {
 	case L2CAP_SDU_UNSEGMENTED:
@@ -3356,16 +3369,18 @@ static int l2cap_ertm_reassembly_sdu(struct sock *sk, struct sk_buff *skb, u16 c
 			goto drop;
 
 		pi->sdu_len = get_unaligned_le16(skb->data);
-		skb_pull(skb, 2);
 
 		if (pi->sdu_len > pi->imtu)
 			goto disconnect;
 
 		pi->sdu = bt_skb_alloc(pi->sdu_len, GFP_ATOMIC);
-		if (!pi->sdu) {
-			err = -ENOMEM;
-			break;
-		}
+		if (!pi->sdu)
+			return -ENOMEM;
+
+		/* pull sdu_len bytes only after alloc, because of Local Busy
+		 * condition we have to be sure that this will be executed
+		 * only once, i.e., when alloc does not fail */
+		skb_pull(skb, 2);
 
 		memcpy(skb_put(pi->sdu, skb->len), skb->data, skb->len);
 
@@ -3395,28 +3410,40 @@ static int l2cap_ertm_reassembly_sdu(struct sock *sk, struct sk_buff *skb, u16 c
 		if (!pi->sdu)
 			goto disconnect;
 
-		memcpy(skb_put(pi->sdu, skb->len), skb->data, skb->len);
+		if (!(pi->conn_state & L2CAP_CONN_SAR_RETRY)) {
+			memcpy(skb_put(pi->sdu, skb->len), skb->data, skb->len);
 
-		pi->conn_state &= ~L2CAP_CONN_SAR_SDU;
-		pi->partial_sdu_len += skb->len;
+			pi->partial_sdu_len += skb->len;
 
-		if (pi->partial_sdu_len > pi->imtu)
-			goto drop;
+			if (pi->partial_sdu_len > pi->imtu)
+				goto drop;
 
-		if (pi->partial_sdu_len != pi->sdu_len)
-			goto drop;
+			if (pi->partial_sdu_len != pi->sdu_len)
+				goto drop;
+		}
 
 		_skb = skb_clone(pi->sdu, GFP_ATOMIC);
+		if (!_skb) {
+			pi->conn_state |= L2CAP_CONN_SAR_RETRY;
+			return -ENOMEM;
+		}
+
 		err = sock_queue_rcv_skb(sk, _skb);
-		if (err < 0)
+		if (err < 0) {
 			kfree_skb(_skb);
+			pi->conn_state |= L2CAP_CONN_SAR_RETRY;
+			return err;
+		}
+
+		pi->conn_state &= ~L2CAP_CONN_SAR_RETRY;
+		pi->conn_state &= ~L2CAP_CONN_SAR_SDU;
 
 		kfree_skb(pi->sdu);
 		break;
 	}
 
 	kfree_skb(skb);
-	return err;
+	return 0;
 
 drop:
 	kfree_skb(pi->sdu);
@@ -3428,6 +3455,115 @@ disconnect:
 	return 0;
 }
 
+static void l2cap_busy_work(struct work_struct *work)
+{
+	DECLARE_WAITQUEUE(wait, current);
+	struct l2cap_pinfo *pi =
+		container_of(work, struct l2cap_pinfo, busy_work);
+	struct sock *sk = (struct sock *)pi;
+	int n_tries = 0, timeo = HZ/5, err;
+	struct sk_buff *skb;
+	u16 control;
+
+	lock_sock(sk);
+
+	add_wait_queue(sk->sk_sleep, &wait);
+	while ((skb = skb_peek(BUSY_QUEUE(sk)))) {
+		set_current_state(TASK_INTERRUPTIBLE);
+
+		if (n_tries++ > L2CAP_LOCAL_BUSY_TRIES) {
+			err = -EBUSY;
+			l2cap_send_disconn_req(pi->conn, sk);
+			goto done;
+		}
+
+		if (!timeo)
+			timeo = HZ/5;
+
+		if (signal_pending(current)) {
+			err = sock_intr_errno(timeo);
+			goto done;
+		}
+
+		release_sock(sk);
+		timeo = schedule_timeout(timeo);
+		lock_sock(sk);
+
+		err = sock_error(sk);
+		if (err)
+			goto done;
+
+		while ((skb = skb_dequeue(BUSY_QUEUE(sk)))) {
+			control = bt_cb(skb)->sar << L2CAP_CTRL_SAR_SHIFT;
+			err = l2cap_ertm_reassembly_sdu(sk, skb, control);
+			if (err < 0) {
+				skb_queue_head(BUSY_QUEUE(sk), skb);
+				break;
+			}
+
+			pi->buffer_seq = (pi->buffer_seq + 1) % 64;
+		}
+
+		if (!skb)
+			break;
+	}
+
+	if (!(pi->conn_state & L2CAP_CONN_RNR_SENT))
+		goto done;
+
+	control = pi->buffer_seq << L2CAP_CTRL_REQSEQ_SHIFT;
+	control |= L2CAP_SUPER_RCV_READY | L2CAP_CTRL_POLL;
+	l2cap_send_sframe(pi, control);
+	l2cap_pi(sk)->retry_count = 1;
+
+	del_timer(&pi->retrans_timer);
+	__mod_monitor_timer();
+
+	l2cap_pi(sk)->conn_state |= L2CAP_CONN_WAIT_F;
+
+done:
+	pi->conn_state &= ~L2CAP_CONN_LOCAL_BUSY;
+	pi->conn_state &= ~L2CAP_CONN_RNR_SENT;
+
+	set_current_state(TASK_RUNNING);
+	remove_wait_queue(sk->sk_sleep, &wait);
+
+	release_sock(sk);
+}
+
+static int l2cap_push_rx_skb(struct sock *sk, struct sk_buff *skb, u16 control)
+{
+	struct l2cap_pinfo *pi = l2cap_pi(sk);
+	int sctrl, err;
+
+	if (pi->conn_state & L2CAP_CONN_LOCAL_BUSY) {
+		bt_cb(skb)->sar = control >> L2CAP_CTRL_SAR_SHIFT;
+		__skb_queue_tail(BUSY_QUEUE(sk), skb);
+		return -EBUSY;
+	}
+
+	err = l2cap_ertm_reassembly_sdu(sk, skb, control);
+	if (err >= 0) {
+		pi->buffer_seq = (pi->buffer_seq + 1) % 64;
+		return err;
+	}
+
+	/* Busy Condition */
+	pi->conn_state |= L2CAP_CONN_LOCAL_BUSY;
+	bt_cb(skb)->sar = control >> L2CAP_CTRL_SAR_SHIFT;
+	__skb_queue_tail(BUSY_QUEUE(sk), skb);
+
+	sctrl = pi->buffer_seq << L2CAP_CTRL_REQSEQ_SHIFT;
+	sctrl |= L2CAP_SUPER_RCV_NOT_READY;
+	l2cap_send_sframe(pi, sctrl);
+
+	pi->conn_state |= L2CAP_CONN_RNR_SENT;
+
+	queue_work(_busy_wq, &pi->busy_work);
+
+	return err;
+}
+
 static int l2cap_streaming_reassembly_sdu(struct sock *sk, struct sk_buff *skb, u16 control)
 {
 	struct l2cap_pinfo *pi = l2cap_pi(sk);
@@ -3614,6 +3750,9 @@ static inline int l2cap_data_channel_iframe(struct sock *sk, u16 rx_control, str
 		goto drop;
 	}
 
+	if (pi->conn_state == L2CAP_CONN_LOCAL_BUSY)
+		goto drop;
+
 	if (pi->conn_state & L2CAP_CONN_SREJ_SENT) {
 		struct srej_list *first;
 
@@ -3662,6 +3801,7 @@ static inline int l2cap_data_channel_iframe(struct sock *sk, u16 rx_control, str
 		pi->buffer_seq_srej = pi->buffer_seq;
 
 		__skb_queue_head_init(SREJ_QUEUE(sk));
+		__skb_queue_head_init(BUSY_QUEUE(sk));
 		l2cap_add_to_srej_queue(sk, skb, tx_seq, sar);
 
 		pi->conn_state |= L2CAP_CONN_SEND_PBIT;
@@ -3691,11 +3831,9 @@ expected:
 		}
 	}
 
-	pi->buffer_seq = (pi->buffer_seq + 1) % 64;
-
-	err = l2cap_ertm_reassembly_sdu(sk, skb, rx_control);
+	err = l2cap_push_rx_skb(sk, skb, rx_control);
 	if (err < 0)
-		return err;
+		return 0;
 
 	__mod_ack_timer();
 
@@ -4406,6 +4544,10 @@ static int __init l2cap_init(void)
 	if (err < 0)
 		return err;
 
+	_busy_wq = create_singlethread_workqueue("l2cap");
+	if (!_busy_wq)
+		goto error;
+
 	err = bt_sock_register(BTPROTO_L2CAP, &l2cap_sock_family_ops);
 	if (err < 0) {
 		BT_ERR("L2CAP socket registration failed");
@@ -4440,6 +4582,9 @@ static void __exit l2cap_exit(void)
 {
 	debugfs_remove(l2cap_debugfs);
 
+	flush_workqueue(_busy_wq);
+	destroy_workqueue(_busy_wq);
+
 	if (bt_sock_unregister(BTPROTO_L2CAP) < 0)
 		BT_ERR("L2CAP socket unregistration failed");