Bluetooth: Add support for Retransmission and Monitor Timers

L2CAP uses retransmission and monitor timers to inquiry the other side
about unacked I-frames. After sending each I-frame we (re)start the
retransmission timer. If it expires, we start a monitor timer that send a
S-frame with P bit set and wait for S-frame with F bit set. If monitor
timer expires, try again, at a maximum of L2CAP_DEFAULT_MAX_TX.

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

2 files changed, 13 insertions, 3 deletions

diff --git a/include/net/bluetooth/bluetooth.h b/include/net/bluetooth/bluetooth.h
index 65a5cf868fd6..b8b9a8479525 100644
--- a/include/net/bluetooth/bluetooth.h
+++ b/include/net/bluetooth/bluetooth.h
@@ -139,6 +139,7 @@ struct bt_skb_cb {
         __u8 pkt_type;
         __u8 incoming;
         __u8 tx_seq;
+        __u8 retries;
 };
 #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 a1d8ec468ef3..2cf7003cb1b6 100644
--- a/include/net/bluetooth/l2cap.h
+++ b/include/net/bluetooth/l2cap.h
@@ -31,9 +31,9 @@
 #define L2CAP_DEFAULT_FLUSH_TO          0xffff
 #define L2CAP_DEFAULT_TX_WINDOW         63
 #define L2CAP_DEFAULT_NUM_TO_ACK        (L2CAP_DEFAULT_TX_WINDOW/5)
-#define L2CAP_DEFAULT_MAX_RECEIVE       1
-#define L2CAP_DEFAULT_RETRANS_TO        300    /* 300 milliseconds */
-#define L2CAP_DEFAULT_MONITOR_TO        1000   /* 1 second */
+#define L2CAP_DEFAULT_MAX_TX            3
+#define L2CAP_DEFAULT_RETRANS_TO        1000    /* 1 second */
+#define L2CAP_DEFAULT_MONITOR_TO        12000   /* 12 seconds */
 #define L2CAP_DEFAULT_MAX_PDU_SIZE      672
 
 #define L2CAP_CONN_TIMEOUT      (40000) /* 40 seconds */
@@ -318,6 +318,7 @@ struct l2cap_pinfo {
         __u8            req_seq;
         __u8            expected_tx_seq;
         __u8            unacked_frames;
+        __u8            retry_count;
         __u8            num_to_ack;
         __u16           sdu_len;
         __u16           partial_sdu_len;
@@ -333,6 +334,8 @@ struct l2cap_pinfo {
 
         __le16          sport;
 
+        struct timer_list       retrans_timer;
+        struct timer_list       monitor_timer;
         struct sk_buff_head     tx_queue;
         struct l2cap_conn       *conn;
         struct sock             *next_c;
@@ -352,6 +355,12 @@ struct l2cap_pinfo {
 
 #define L2CAP_CONN_SAR_SDU         0x01
 #define L2CAP_CONN_UNDER_REJ       0x02
+#define L2CAP_CONN_WAIT_F          0x04
+
+#define __mod_retrans_timer() mod_timer(&l2cap_pi(sk)->retrans_timer, \
+                jiffies +  msecs_to_jiffies(L2CAP_DEFAULT_RETRANS_TO));
+#define __mod_monitor_timer() mod_timer(&l2cap_pi(sk)->monitor_timer, \
+                jiffies + msecs_to_jiffies(L2CAP_DEFAULT_MONITOR_TO));
 
 static inline int l2cap_tx_window_full(struct sock *sk)
 {