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>
diff --git a/net/bluetooth/l2cap.c b/net/bluetooth/l2cap.c
index 35e9f5b..97172f7 100644
--- a/net/bluetooth/l2cap.c
+++ b/net/bluetooth/l2cap.c
@@ -1178,6 +1178,39 @@
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;
+ control |= L2CAP_SUPER_RCV_READY;
+ 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_F;
+
+ control = L2CAP_CTRL_POLL;
+ control |= L2CAP_SUPER_RCV_READY;
+ l2cap_send_sframe(l2cap_pi(sk), control);
+}
+
static void l2cap_drop_acked_frames(struct sock *sk)
{
struct sk_buff *skb;
@@ -1192,6 +1225,9 @@
l2cap_pi(sk)->unacked_frames--;
}
+ if (!l2cap_pi(sk)->unacked_frames)
+ del_timer(&l2cap_pi(sk)->retrans_timer);
+
return;
}
@@ -1216,19 +1252,32 @@
u16 control;
int err;
+ if (pi->conn_state & L2CAP_CONN_WAIT_F)
+ 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 = get_unaligned_le16(tx_skb->data + L2CAP_HDR_SIZE);
control |= (pi->req_seq << L2CAP_CTRL_REQSEQ_SHIFT)
| (pi->next_tx_seq << L2CAP_CTRL_TXSEQ_SHIFT);
put_unaligned_le16(control, tx_skb->data + L2CAP_HDR_SIZE);
+
err = l2cap_do_send(sk, tx_skb);
if (err < 0) {
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;
@@ -1365,6 +1414,8 @@
kfree_skb(skb);
return ERR_PTR(err);
}
+
+ bt_cb(skb)->retries = 0;
return skb;
}
@@ -2058,7 +2109,7 @@
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);
@@ -2553,6 +2604,12 @@
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;
@@ -2662,6 +2719,8 @@
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);
@@ -2686,6 +2745,8 @@
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);
@@ -2991,9 +3052,26 @@
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;
+ control |= L2CAP_SUPER_RCV_READY;
+ l2cap_send_sframe(l2cap_pi(sk), control);
+ } else if (rx_control & L2CAP_CTRL_FINAL) {
+ if (!(pi->conn_state & L2CAP_CONN_WAIT_F))
+ break;
+
+ pi->conn_state &= ~L2CAP_CONN_WAIT_F;
+ 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);
+ if (pi->unacked_frames > 0)
+ __mod_retrans_timer();
+ l2cap_ertm_send(sk);
+ }
break;
case L2CAP_SUPER_REJECT: