Bluetooth: Initial support for retransmission of packets with REJ frames
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>
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@ -351,6 +351,7 @@ struct l2cap_pinfo {
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#define L2CAP_CONF_MAX_CONF_RSP 2
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#define L2CAP_CONN_SAR_SDU 0x01
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#define L2CAP_CONN_UNDER_REJ 0x02
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static inline int l2cap_tx_window_full(struct sock *sk)
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{
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@ -2951,8 +2951,9 @@ static inline int l2cap_data_channel_iframe(struct sock *sk, u16 rx_control, str
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BT_DBG("sk %p rx_control 0x%4.4x len %d", sk, rx_control, skb->len);
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if (tx_seq != pi->expected_tx_seq)
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return -EINVAL;
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if (tx_seq == pi->expected_tx_seq) {
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if (pi->conn_state & L2CAP_CONN_UNDER_REJ)
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pi->conn_state &= ~L2CAP_CONN_UNDER_REJ;
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err = l2cap_sar_reassembly_sdu(sk, skb, rx_control);
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if (err < 0)
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@ -2961,12 +2962,25 @@ static inline int l2cap_data_channel_iframe(struct sock *sk, u16 rx_control, str
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pi->expected_tx_seq = (pi->expected_tx_seq + 1) % 64;
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pi->num_to_ack = (pi->num_to_ack + 1) % L2CAP_DEFAULT_NUM_TO_ACK;
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if (pi->num_to_ack == L2CAP_DEFAULT_NUM_TO_ACK - 1) {
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tx_control |= L2CAP_CTRL_FRAME_TYPE;
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tx_control |= L2CAP_SUPER_RCV_READY;
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tx_control |= pi->expected_tx_seq << L2CAP_CTRL_REQSEQ_SHIFT;
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err = l2cap_send_sframe(pi, tx_control);
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goto send;
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}
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return err;
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} else {
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/* Unexpected txSeq. Send a REJ S-frame */
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kfree_skb(skb);
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if (!(pi->conn_state & L2CAP_CONN_UNDER_REJ)) {
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tx_control |= L2CAP_SUPER_REJECT;
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tx_control |= pi->expected_tx_seq << L2CAP_CTRL_REQSEQ_SHIFT;
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pi->conn_state |= L2CAP_CONN_UNDER_REJ;
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goto send;
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}
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}
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return 0;
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send:
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return l2cap_send_sframe(pi, tx_control);
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}
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static inline int l2cap_data_channel_sframe(struct sock *sk, u16 rx_control, struct sk_buff *skb)
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@ -2982,8 +2996,18 @@ static inline int l2cap_data_channel_sframe(struct sock *sk, u16 rx_control, str
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l2cap_ertm_send(sk);
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break;
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case L2CAP_SUPER_RCV_NOT_READY:
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case L2CAP_SUPER_REJECT:
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pi->expected_ack_seq = __get_reqseq(rx_control);
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l2cap_drop_acked_frames(sk);
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sk->sk_send_head = TX_QUEUE(sk)->next;
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pi->next_tx_seq = pi->expected_ack_seq;
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l2cap_ertm_send(sk);
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break;
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case L2CAP_SUPER_RCV_NOT_READY:
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case L2CAP_SUPER_SELECT_REJECT:
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break;
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}
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@ -3030,6 +3054,11 @@ static inline int l2cap_data_channel(struct l2cap_conn *conn, u16 cid, struct sk
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if (__is_sar_start(control))
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len -= 2;
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/*
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* We can just drop the corrupted I-frame here.
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* Receiver will miss it and start proper recovery
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* procedures and ask retransmission.
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*/
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if (len > L2CAP_DEFAULT_MAX_PDU_SIZE)
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goto drop;
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