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Bluetooth: Initial support for retransmission of packets with REJ frames

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When receiving an I-frame with unexpected txSeq, receiver side start the
recovery procedure by sending a REJ S-frame to the transmitter side. So
the transmitter can re-send the lost I-frame.

This patch just adds a basic support for retransmission, it doesn't
mean that ERTM now has full support for packet retransmission.

Signed-off-by: Gustavo F. Padovan <gustavo@las.ic.unicamp.br>
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>
This commit is contained in:
Gustavo F. Padovan 2009-08-20 22:25:59 -03:00 committed by Marcel Holtmann
parent c74e560cd0
commit 30afb5b2aa
2 changed files with 44 additions and 14 deletions
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1
include/net/bluetooth/l2cap.h
View file

@ -351,6 +351,7 @@ struct l2cap_pinfo {
#define L2CAP_CONF_MAX_CONF_RSP 2
#define L2CAP_CONN_SAR_SDU 0x01
#define L2CAP_CONN_UNDER_REJ 0x02
static inline int l2cap_tx_window_full(struct sock *sk)
{

57
net/bluetooth/l2cap.c
View file

@ -2951,22 +2951,36 @@ static inline int l2cap_data_channel_iframe(struct sock *sk, u16 rx_control, str
BT_DBG("sk %p rx_control 0x%4.4x len %d", sk, rx_control, skb->len);
if (tx_seq != pi->expected_tx_seq)
return -EINVAL;
if (tx_seq == pi->expected_tx_seq) {
if (pi->conn_state & L2CAP_CONN_UNDER_REJ)
pi->conn_state &= ~L2CAP_CONN_UNDER_REJ;
err = l2cap_sar_reassembly_sdu(sk, skb, rx_control);
if (err < 0)
return err;
err = l2cap_sar_reassembly_sdu(sk, skb, rx_control);
if (err < 0)
return err;
pi->expected_tx_seq = (pi->expected_tx_seq + 1) % 64;
pi->num_to_ack = (pi->num_to_ack + 1) % L2CAP_DEFAULT_NUM_TO_ACK;
if (pi->num_to_ack == L2CAP_DEFAULT_NUM_TO_ACK - 1) {
tx_control |= L2CAP_CTRL_FRAME_TYPE;
tx_control |= L2CAP_SUPER_RCV_READY;
tx_control |= pi->expected_tx_seq << L2CAP_CTRL_REQSEQ_SHIFT;
err = l2cap_send_sframe(pi, tx_control);
pi->expected_tx_seq = (pi->expected_tx_seq + 1) % 64;
pi->num_to_ack = (pi->num_to_ack + 1) % L2CAP_DEFAULT_NUM_TO_ACK;
if (pi->num_to_ack == L2CAP_DEFAULT_NUM_TO_ACK - 1) {
tx_control |= L2CAP_SUPER_RCV_READY;
tx_control |= pi->expected_tx_seq << L2CAP_CTRL_REQSEQ_SHIFT;
goto send;
}
} else {
/* Unexpected txSeq. Send a REJ S-frame */
kfree_skb(skb);
if (!(pi->conn_state & L2CAP_CONN_UNDER_REJ)) {
tx_control |= L2CAP_SUPER_REJECT;
tx_control |= pi->expected_tx_seq << L2CAP_CTRL_REQSEQ_SHIFT;
pi->conn_state |= L2CAP_CONN_UNDER_REJ;
goto send;
}
}
return err;
return 0;
send:
return l2cap_send_sframe(pi, tx_control);
}
static inline int l2cap_data_channel_sframe(struct sock *sk, u16 rx_control, struct sk_buff *skb)
@ -2982,8 +2996,18 @@ static inline int l2cap_data_channel_sframe(struct sock *sk, u16 rx_control, str
l2cap_ertm_send(sk);
break;
case L2CAP_SUPER_RCV_NOT_READY:
case L2CAP_SUPER_REJECT:
pi->expected_ack_seq = __get_reqseq(rx_control);
l2cap_drop_acked_frames(sk);
sk->sk_send_head = TX_QUEUE(sk)->next;
pi->next_tx_seq = pi->expected_ack_seq;
l2cap_ertm_send(sk);
break;
case L2CAP_SUPER_RCV_NOT_READY:
case L2CAP_SUPER_SELECT_REJECT:
break;
}
@ -3030,6 +3054,11 @@ static inline int l2cap_data_channel(struct l2cap_conn *conn, u16 cid, struct sk
if (__is_sar_start(control))
len -= 2;
/*
* We can just drop the corrupted I-frame here.
* Receiver will miss it and start proper recovery
* procedures and ask retransmission.
*/
if (len > L2CAP_DEFAULT_MAX_PDU_SIZE)
goto drop;