Hi Gustavo,
> 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 | 83 +++++++++++++++++++++++++++++++++++--
> 3 files changed, 92 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 653c313..02871df 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 */
> @@ -320,6 +320,7 @@ 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;
> @@ -336,6 +337,8 @@ 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;
> @@ -355,6 +358,12 @@ 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 938d6db..bcfa9b9 100644
> --- a/net/bluetooth/l2cap.c
> +++ b/net/bluetooth/l2cap.c
> @@ -1179,6 +1179,37 @@ 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;
> @@ -1193,6 +1224,9 @@ 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;
> }
>
> @@ -1219,10 +1253,21 @@ 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_seq = pi->next_tx_seq;
> 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)
> @@ -1234,6 +1279,8 @@ static int l2cap_ertm_send(struct sock *sk)
> return err;
> }
>
> + __mod_retrans_timer();
> +
> L2CAP_SEQ_NUM_INC(pi->next_tx_seq);
> bt_cb(skb)->tx_seq = tx_seq;
>
> @@ -1323,6 +1370,8 @@ static struct sk_buff *l2cap_create_pdu(struct sock *sk, struct msghdr *msg, siz
> kfree_skb(skb);
> return ERR_PTR(err);
> }
> +
> + bt_cb(skb)->retries = 0;
> return skb;
> }
>
> @@ -2011,7 +2060,7 @@ 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);
> @@ -2506,6 +2555,12 @@ 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;
> @@ -2615,6 +2670,8 @@ 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);
> @@ -2639,6 +2696,8 @@ 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);
> @@ -2944,9 +3003,25 @@ 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) {
Coding style is } else if.
> + 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 {
Same here.
> + pi->expected_ack_seq = __get_reqseq(rx_control);
> + l2cap_drop_acked_frames(sk);
> + l2cap_ertm_send(sk);
> + }
> break;
>
> case L2CAP_SUPER_REJECT:
Regards
Marcel
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