Commit bed68bde authored by Mat Martineau's avatar Mat Martineau Committed by Johan Hedberg
Browse files

Bluetooth: Send SREJ frames when packets go missing 



The ERTM specification lays out three scenarios for sending SREJ
frames to request retransmission of specific frames.  l2cap_send_srej
requests all frames up to a given txseq that are not already queued
for reassembly.  l2cap_send_srej_tail only requests the most recent
missing frame.  l2cap_send_srej_list resends SREJ frames for data that
was requested for resend but never received.

Signed-off-by: default avatarMat Martineau <mathewm@codeaurora.org>
Signed-off-by: default avatarGustavo Padovan <gustavo.padovan@collabora.co.uk>
parent e1fbd4c1

net/bluetooth/l2cap_core.c

+53 −3
Original line number Diff line number Diff line
@@ -2239,17 +2239,67 @@ int l2cap_chan_send(struct l2cap_chan *chan, struct msghdr *msg, size_t len, 


static void l2cap_send_srej(struct l2cap_chan *chan, u16 txseq)

{

	/* Placeholder */

	struct l2cap_ctrl control;

	u16 seq;



	BT_DBG("chan %p, txseq %d", chan, txseq);



	memset(&control, 0, sizeof(control));

	control.sframe = 1;

	control.super = L2CAP_SUPER_SREJ;



	for (seq = chan->expected_tx_seq; seq != txseq;

	     seq = __next_seq(chan, seq)) {

		if (!l2cap_ertm_seq_in_queue(&chan->srej_q, seq)) {

			control.reqseq = seq;

			l2cap_send_sframe(chan, &control);

			l2cap_seq_list_append(&chan->srej_list, seq);

		}

	}



	chan->expected_tx_seq = __next_seq(chan, txseq);

}



static void l2cap_send_srej_tail(struct l2cap_chan *chan)

{

	/* Placeholder */

	struct l2cap_ctrl control;



	BT_DBG("chan %p", chan);



	if (chan->srej_list.tail == L2CAP_SEQ_LIST_CLEAR)

		return;



	memset(&control, 0, sizeof(control));

	control.sframe = 1;

	control.super = L2CAP_SUPER_SREJ;

	control.reqseq = chan->srej_list.tail;

	l2cap_send_sframe(chan, &control);

}



static void l2cap_send_srej_list(struct l2cap_chan *chan, u16 txseq)

{

	/* Placeholder */

	struct l2cap_ctrl control;

	u16 initial_head;

	u16 seq;



	BT_DBG("chan %p, txseq %d", chan, txseq);



	memset(&control, 0, sizeof(control));

	control.sframe = 1;

	control.super = L2CAP_SUPER_SREJ;



	/* Capture initial list head to allow only one pass through the list. */

	initial_head = chan->srej_list.head;



	do {

		seq = l2cap_seq_list_pop(&chan->srej_list);

		if (seq == txseq || seq == L2CAP_SEQ_LIST_CLEAR)

			break;



		control.reqseq = seq;

		l2cap_send_sframe(chan, &control);

		l2cap_seq_list_append(&chan->srej_list, seq);

	} while (chan->srej_list.head != initial_head);

}



static void l2cap_process_reqseq(struct l2cap_chan *chan, u16 reqseq)

CRA Git | Maintained and supported by SUSTech CRA and CCSE