L2CAP uses rentransmission and monitor timers to inquiry the other side
about unacked I-frames. After send 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, it try again, at a maximum of
L2CAP_DEFAULT_MAX_TX.
Signed-off-by: Gustavo F. Padovan <gustavo@xxxxxxxxxxxxxxxxx>
---
include/net/bluetooth/bluetooth.h | 1 +
include/net/bluetooth/l2cap.h | 15 ++++++-
net/bluetooth/l2cap.c | 80 +++++++++++++++++++++++++++++++++++--
3 files changed, 89 insertions(+), 7 deletions(-)
diff --git a/include/net/bluetooth/bluetooth.h b/include/net/bluetooth/bluetooth.h
index 65a5cf8..b8b9a84 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 a1d8ec4..33aea42 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_ACK 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)
{
diff --git a/net/bluetooth/l2cap.c b/net/bluetooth/l2cap.c
index c7dec70..f04beba 100644
--- a/net/bluetooth/l2cap.c
+++ b/net/bluetooth/l2cap.c
@@ -1178,6 +1178,37 @@ static int l2cap_sock_getname(struct socket *sock, struct sockaddr *addr, int *l
return 0;
}
+static void l2cap_monitor_timeout(unsigned long arg)
+{
+ struct sock *sk = (void *) arg;
+ u16 control;
+
+ if (l2cap_pi(sk)->retry_count >= l2cap_pi(sk)->remote_max_tx) {
+ l2cap_send_disconn_req(l2cap_pi(sk)->conn, sk);
+ return;
+ }
+
+ l2cap_pi(sk)->retry_count++;
+ __mod_monitor_timer();
+
+ control = L2CAP_CTRL_POLL;
+ l2cap_send_sframe(l2cap_pi(sk), control);
+}
+
+static void l2cap_retrans_timeout(unsigned long arg)
+{
+ struct sock *sk = (void *) arg;
+ u16 control;
+
+ l2cap_pi(sk)->retry_count = 1;
+ __mod_monitor_timer();
+
+ l2cap_pi(sk)->conn_state |= L2CAP_CONN_WAIT_ACK;
+
+ control = L2CAP_CTRL_POLL;
+ l2cap_send_sframe(l2cap_pi(sk), control);
+}
+
static void l2cap_drop_acked_frames(struct sock *sk)
{
struct sk_buff *skb;
@@ -1192,6 +1223,9 @@ static void l2cap_drop_acked_frames(struct sock *sk)
l2cap_pi(sk)->unacked_frames--;
}
+ if (!l2cap_pi(sk)->unacked_frames)
+ del_timer(&l2cap_pi(sk)->retrans_timer);
+
return;
}
@@ -1217,9 +1251,20 @@ static int l2cap_ertm_send(struct sock *sk)
u16 *control;
int err;
+ if (pi->conn_state & L2CAP_CONN_WAIT_ACK)
+ return 0;
+
while ((skb = sk->sk_send_head) && (!l2cap_tx_window_full(sk))) {
tx_skb = skb_clone(skb, GFP_ATOMIC);
+ if (pi->remote_max_tx &&
+ bt_cb(skb)->retries == pi->remote_max_tx) {
+ l2cap_send_disconn_req(pi->conn, sk);
+ break;
+ }
+
+ bt_cb(skb)->retries++;
+
control = (u16 *)(skb->data + L2CAP_HDR_SIZE);
*control |= cpu_to_le16(
(pi->req_seq << L2CAP_CTRL_REQSEQ_SHIFT)
@@ -1230,6 +1275,7 @@ static int l2cap_ertm_send(struct sock *sk)
l2cap_send_disconn_req(pi->conn, sk);
return err;
}
+ __mod_retrans_timer();
bt_cb(skb)->tx_seq = pi->next_tx_seq;
pi->next_tx_seq = (pi->next_tx_seq + 1) % 64;
@@ -1366,6 +1412,8 @@ static struct sk_buff *l2cap_create_ertm_pdu(struct sock *sk, struct msghdr *msg
kfree_skb(skb);
return ERR_PTR(err);
}
+
+ bt_cb(skb)->retries = 0;
return skb;
}
@@ -2059,7 +2107,7 @@ done:
case L2CAP_MODE_ERTM:
rfc.mode = L2CAP_MODE_ERTM;
rfc.txwin_size = L2CAP_DEFAULT_TX_WINDOW;
- rfc.max_transmit = L2CAP_DEFAULT_MAX_RECEIVE;
+ rfc.max_transmit = L2CAP_DEFAULT_MAX_TX;
rfc.retrans_timeout = 0;
rfc.monitor_timeout = 0;
rfc.max_pdu_size = cpu_to_le16(L2CAP_DEFAULT_MAX_PDU_SIZE);
@@ -2554,6 +2602,12 @@ static inline int l2cap_config_req(struct l2cap_conn *conn, struct l2cap_cmd_hdr
l2cap_pi(sk)->next_tx_seq = 0;
l2cap_pi(sk)->expected_ack_seq = 0;
l2cap_pi(sk)->unacked_frames = 0;
+
+ setup_timer(&l2cap_pi(sk)->retrans_timer,
+ l2cap_retrans_timeout, (unsigned long) sk);
+ setup_timer(&l2cap_pi(sk)->monitor_timer,
+ l2cap_monitor_timeout, (unsigned long) sk);
+
__skb_queue_head_init(TX_QUEUE(sk));
l2cap_chan_ready(sk);
goto unlock;
@@ -2663,6 +2717,8 @@ static inline int l2cap_disconnect_req(struct l2cap_conn *conn, struct l2cap_cmd
sk->sk_shutdown = SHUTDOWN_MASK;
skb_queue_purge(TX_QUEUE(sk));
+ del_timer(&l2cap_pi(sk)->retrans_timer);
+ del_timer(&l2cap_pi(sk)->monitor_timer);
l2cap_chan_del(sk, ECONNRESET);
bh_unlock_sock(sk);
@@ -2687,6 +2743,8 @@ static inline int l2cap_disconnect_rsp(struct l2cap_conn *conn, struct l2cap_cmd
return 0;
skb_queue_purge(TX_QUEUE(sk));
+ del_timer(&l2cap_pi(sk)->retrans_timer);
+ del_timer(&l2cap_pi(sk)->monitor_timer);
l2cap_chan_del(sk, 0);
bh_unlock_sock(sk);
@@ -2992,9 +3050,23 @@ static inline int l2cap_data_channel_sframe(struct sock *sk, u16 rx_control, str
switch (rx_control & L2CAP_CTRL_SUPERVISE) {
case L2CAP_SUPER_RCV_READY:
- pi->expected_ack_seq = __get_reqseq(rx_control);
- l2cap_drop_acked_frames(sk);
- l2cap_ertm_send(sk);
+ if (rx_control & L2CAP_CTRL_POLL) {
+ u16 control = L2CAP_CTRL_FINAL;
+ l2cap_send_sframe(l2cap_pi(sk), control);
+ } else if (rx_control & L2CAP_CTRL_FINAL) {
+ if (pi->conn_state & L2CAP_CONN_WAIT_ACK)
+ break;
+
+ pi->conn_state &= !L2CAP_CONN_WAIT_ACK;
+ del_timer(&pi->monitor_timer);
+
+ if (pi->unacked_frames > 0)
+ __mod_retrans_timer();
+ } else {
+ pi->expected_ack_seq = __get_reqseq(rx_control);
+ l2cap_drop_acked_frames(sk);
+ l2cap_ertm_send(sk);
+ }
break;
case L2CAP_SUPER_REJECT:
--
1.6.3.3
--
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