Bluetooth: Full support for receiving L2CAP SREJ frames

Support for receiving of SREJ frames as specified by the state table.

Signed-off-by: Gustavo F. Padovan <gustavo@las.ic.unicamp.br>
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>

2 files changed, 32 insertions, 1 deletions

diff --git a/include/net/bluetooth/l2cap.h b/include/net/bluetooth/l2cap.h
index 9f2126a4f6f5..7ca614ac5d43 100644
--- a/include/net/bluetooth/l2cap.h
+++ b/include/net/bluetooth/l2cap.h
@@ -328,6 +328,7 @@ struct l2cap_pinfo {
         __u8            expected_tx_seq;
         __u8            buffer_seq;
         __u8            buffer_seq_srej;
+        __u8            srej_save_reqseq;
         __u8            unacked_frames;
         __u8            retry_count;
         __u8            num_to_ack;
@@ -370,6 +371,8 @@ struct l2cap_pinfo {
 #define L2CAP_CONN_SAR_SDU         0x01
 #define L2CAP_CONN_SREJ_SENT       0x02
 #define L2CAP_CONN_WAIT_F          0x04
+#define L2CAP_CONN_SREJ_ACT        0x08
+#define L2CAP_CONN_SEND_PBIT       0x10
 
 #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 70aff921db8c..c04526f3df2e 100644
--- a/net/bluetooth/l2cap.c
+++ b/net/bluetooth/l2cap.c
@@ -3241,6 +3241,10 @@ static void l2cap_send_srejframe(struct sock *sk, u8 tx_seq)
         while (tx_seq != pi->expected_tx_seq) {
                 control = L2CAP_SUPER_SELECT_REJECT;
                 control |= pi->expected_tx_seq << L2CAP_CTRL_REQSEQ_SHIFT;
+                if (pi->conn_state & L2CAP_CONN_SEND_PBIT) {
+                        control |= L2CAP_CTRL_POLL;
+                        pi->conn_state &= ~L2CAP_CONN_SEND_PBIT;
+                }
                 l2cap_send_sframe(pi, control);
 
                 new = kzalloc(sizeof(struct srej_list), GFP_ATOMIC);
@@ -3300,6 +3304,8 @@ static inline int l2cap_data_channel_iframe(struct sock *sk, u16 rx_control, str
                 __skb_queue_head_init(SREJ_QUEUE(sk));
                 l2cap_add_to_srej_queue(sk, skb, tx_seq, sar);
 
+                pi->conn_state |= L2CAP_CONN_SEND_PBIT;
+
                 l2cap_send_srejframe(sk, tx_seq);
         }
         return 0;
@@ -3370,7 +3376,29 @@ static inline int l2cap_data_channel_sframe(struct sock *sk, u16 rx_control, str
                 break;
 
         case L2CAP_SUPER_SELECT_REJECT:
-                l2cap_retransmit_frame(sk, tx_seq);
+                if (rx_control & L2CAP_CTRL_POLL) {
+                        l2cap_retransmit_frame(sk, tx_seq);
+                        pi->expected_ack_seq = tx_seq;
+                        l2cap_drop_acked_frames(sk);
+                        l2cap_ertm_send(sk);
+                        if (pi->conn_state & L2CAP_CONN_WAIT_F) {
+                                pi->srej_save_reqseq = tx_seq;
+                                pi->conn_state |= L2CAP_CONN_SREJ_ACT;
+                        }
+                } else if (rx_control & L2CAP_CTRL_FINAL) {
+                        if ((pi->conn_state & L2CAP_CONN_SREJ_ACT) &&
+                                        pi->srej_save_reqseq == tx_seq)
+                                pi->srej_save_reqseq &= ~L2CAP_CONN_SREJ_ACT;
+                        else
+                                l2cap_retransmit_frame(sk, tx_seq);
+                }
+                else {
+                        l2cap_retransmit_frame(sk, tx_seq);
+                        if (pi->conn_state & L2CAP_CONN_WAIT_F) {
+                                pi->srej_save_reqseq = tx_seq;
+                                pi->conn_state |= L2CAP_CONN_SREJ_ACT;
+                        }
+                }
                 break;
 
         case L2CAP_SUPER_RCV_NOT_READY: