Bluetooth: Implement 'Send IorRRorRNR' event

After receive a RR with P bit set ERTM shall use this funcion to choose
what type of frame to reply with F bit = 1.

Signed-off-by: Gustavo F. Padovan <padovan@profusion.mobi>
Reviewed-by: João Paulo Rechi Vita <jprvita@profusion.mobi>
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>
diff --git a/net/bluetooth/l2cap.c b/net/bluetooth/l2cap.c
index a9c152a..06687e2 100644
--- a/net/bluetooth/l2cap.c
+++ b/net/bluetooth/l2cap.c
@@ -1383,6 +1383,10 @@
 		bt_cb(skb)->retries++;
 
 		control = get_unaligned_le16(tx_skb->data + L2CAP_HDR_SIZE);
+		if (pi->conn_state & L2CAP_CONN_SEND_FBIT) {
+			control |= L2CAP_CTRL_FINAL;
+			pi->conn_state &= ~L2CAP_CONN_SEND_FBIT;
+		}
 		control |= (pi->buffer_seq << L2CAP_CTRL_REQSEQ_SHIFT)
 				| (pi->next_tx_seq << L2CAP_CTRL_TXSEQ_SHIFT);
 		put_unaligned_le16(control, tx_skb->data + L2CAP_HDR_SIZE);
@@ -1404,6 +1408,7 @@
 		pi->next_tx_seq = (pi->next_tx_seq + 1) % 64;
 
 		pi->unacked_frames++;
+		pi->frames_sent++;
 
 		if (skb_queue_is_last(TX_QUEUE(sk), skb))
 			sk->sk_send_head = NULL;
@@ -2191,6 +2196,7 @@
 	l2cap_pi(sk)->unacked_frames = 0;
 	l2cap_pi(sk)->buffer_seq = 0;
 	l2cap_pi(sk)->num_to_ack = 0;
+	l2cap_pi(sk)->frames_sent = 0;
 
 	setup_timer(&l2cap_pi(sk)->retrans_timer,
 			l2cap_retrans_timeout, (unsigned long) sk);
@@ -3148,6 +3154,38 @@
 	return 0;
 }
 
+static inline void l2cap_send_i_or_rr_or_rnr(struct sock *sk)
+{
+	struct l2cap_pinfo *pi = l2cap_pi(sk);
+	u16 control = 0;
+
+	pi->frames_sent = 0;
+	pi->conn_state |= L2CAP_CONN_SEND_FBIT;
+
+	control |= pi->buffer_seq << L2CAP_CTRL_REQSEQ_SHIFT;
+
+	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_SEND_FBIT;
+	}
+
+	if (pi->conn_state & L2CAP_CONN_REMOTE_BUSY && pi->unacked_frames > 0)
+		__mod_retrans_timer();
+
+	l2cap_ertm_send(sk);
+
+	if (!(pi->conn_state & L2CAP_CONN_LOCAL_BUSY) &&
+			pi->frames_sent == 0) {
+		control |= L2CAP_SUPER_RCV_READY;
+		if (pi->conn_state & L2CAP_CONN_SEND_FBIT) {
+			control |= L2CAP_CTRL_FINAL;
+			pi->conn_state &= ~L2CAP_CONN_SEND_FBIT;
+		}
+		l2cap_send_sframe(pi, control);
+	}
+}
+
 static void l2cap_add_to_srej_queue(struct sock *sk, struct sk_buff *skb, u8 tx_seq, u8 sar)
 {
 	struct sk_buff *next_skb;
@@ -3418,10 +3456,7 @@
 	switch (rx_control & L2CAP_CTRL_SUPERVISE) {
 	case L2CAP_SUPER_RCV_READY:
 		if (rx_control & L2CAP_CTRL_POLL) {
-			u16 control = L2CAP_CTRL_FINAL;
-			control |= L2CAP_SUPER_RCV_READY |
-				(pi->buffer_seq << L2CAP_CTRL_REQSEQ_SHIFT);
-			l2cap_send_sframe(l2cap_pi(sk), control);
+			l2cap_send_i_or_rr_or_rnr(sk);
 			pi->conn_state &= ~L2CAP_CONN_REMOTE_BUSY;
 
 		} else if (rx_control & L2CAP_CTRL_FINAL) {