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Commit cec8ab6e authored by Mat Martineau's avatar Mat Martineau Committed by Johan Hedberg
Browse files

Bluetooth: Consolidate common receive code for ERTM and streaming mode 



Creates a new l2cap_data_rcv function that combines previous code from
l2cap_ertm_data_rcv and l2cap_data_channel.  This reduces duplicate
code for streaming mode, and sets up a framework for the ERTM receive
state machine.

Signed-off-by: default avatarMat Martineau <mathewm@codeaurora.org>
Signed-off-by: default avatarGustavo Padovan <gustavo.padovan@collabora.co.uk>
parent a67d7f6f

net/bluetooth/l2cap_core.c

+62 −64
Original line number Diff line number Diff line
@@ -791,9 +791,11 @@ static inline void __unpack_control(struct l2cap_chan *chan, 
	if (test_bit(FLAG_EXT_CTRL, &chan->flags)) {

		__unpack_extended_control(get_unaligned_le32(skb->data),

					  &bt_cb(skb)->control);

		skb_pull(skb, L2CAP_EXT_CTRL_SIZE);

	} else {

		__unpack_enhanced_control(get_unaligned_le16(skb->data),

					  &bt_cb(skb)->control);

		skb_pull(skb, L2CAP_ENH_CTRL_SIZE);

	}

}
@@ -4820,27 +4822,39 @@ static inline int l2cap_data_channel_sframe(struct l2cap_chan *chan, u32 rx_cont 
	return 0;

}



static int l2cap_ertm_data_rcv(struct l2cap_chan *chan, struct sk_buff *skb)

static int l2cap_rx(struct l2cap_chan *chan, struct l2cap_ctrl *control,

		    struct sk_buff *skb, u8 event)

{

	u32 control;

	u16 req_seq;

	int len, next_tx_seq_offset, req_seq_offset;

	/* Placeholder */

	return -ENOTSUPP;

}



static int l2cap_stream_rx(struct l2cap_chan *chan, struct l2cap_ctrl *control,

			   struct sk_buff *skb)

{

	/* Placeholder */

	return -ENOTSUPP;

}



static int l2cap_data_rcv(struct l2cap_chan *chan, struct sk_buff *skb)

{

	struct l2cap_ctrl *control = &bt_cb(skb)->control;

	u16 len;

	u8 event;



	__unpack_control(chan, skb);



	control = __get_control(chan, skb->data);

	skb_pull(skb, __ctrl_size(chan));

	len = skb->len;



	/*

	 * We can just drop the corrupted I-frame here.

	 * Receiver will miss it and start proper recovery

	 * procedures and ask retransmission.

	 * procedures and ask for retransmission.

	 */

	if (l2cap_check_fcs(chan, skb))

		goto drop;



	if (__is_sar_start(chan, control) && !__is_sframe(chan, control))

	if (!control->sframe && control->sar == L2CAP_SAR_START)

		len -= L2CAP_SDULEN_SIZE;



	if (chan->fcs == L2CAP_FCS_CRC16)
@@ -4851,34 +4865,57 @@ static int l2cap_ertm_data_rcv(struct l2cap_chan *chan, struct sk_buff *skb) 
		goto drop;

	}



	req_seq = __get_reqseq(chan, control);



	req_seq_offset = __seq_offset(chan, req_seq, chan->expected_ack_seq);

	if (!control->sframe) {

		int err;



	next_tx_seq_offset = __seq_offset(chan, chan->next_tx_seq,

						chan->expected_ack_seq);

		BT_DBG("iframe sar %d, reqseq %d, final %d, txseq %d",

		       control->sar, control->reqseq, control->final,

		       control->txseq);



	/* check for invalid req-seq */

	if (req_seq_offset > next_tx_seq_offset) {

		l2cap_send_disconn_req(chan->conn, chan, ECONNRESET);

		/* Validate F-bit - F=0 always valid, F=1 only

		 * valid in TX WAIT_F

		 */

		if (control->final && chan->tx_state != L2CAP_TX_STATE_WAIT_F)

			goto drop;

	}



	if (!__is_sframe(chan, control)) {

		if (len < 0) {

			l2cap_send_disconn_req(chan->conn, chan, ECONNRESET);

			goto drop;

		if (chan->mode != L2CAP_MODE_STREAMING) {

			event = L2CAP_EV_RECV_IFRAME;

			err = l2cap_rx(chan, control, skb, event);

		} else {

			err = l2cap_stream_rx(chan, control, skb);

		}



		l2cap_data_channel_iframe(chan, control, skb);

		if (err)

			l2cap_send_disconn_req(chan->conn, chan,

					       ECONNRESET);

	} else {

		const u8 rx_func_to_event[4] = {

			L2CAP_EV_RECV_RR, L2CAP_EV_RECV_REJ,

			L2CAP_EV_RECV_RNR, L2CAP_EV_RECV_SREJ

		};



		/* Only I-frames are expected in streaming mode */

		if (chan->mode == L2CAP_MODE_STREAMING)

			goto drop;



		BT_DBG("sframe reqseq %d, final %d, poll %d, super %d",

		       control->reqseq, control->final, control->poll,

		       control->super);



		if (len != 0) {

			BT_ERR("%d", len);

			l2cap_send_disconn_req(chan->conn, chan, ECONNRESET);

			goto drop;

		}



		l2cap_data_channel_sframe(chan, control, skb);

		/* Validate F and P bits */

		if (control->final && (control->poll ||

				       chan->tx_state != L2CAP_TX_STATE_WAIT_F))

			goto drop;



		event = rx_func_to_event[control->super];

		if (l2cap_rx(chan, control, skb, event))

			l2cap_send_disconn_req(chan->conn, chan, ECONNRESET);

	}



	return 0;
@@ -4891,9 +4928,6 @@ static int l2cap_ertm_data_rcv(struct l2cap_chan *chan, struct sk_buff *skb) 
static inline int l2cap_data_channel(struct l2cap_conn *conn, u16 cid, struct sk_buff *skb)

{

	struct l2cap_chan *chan;

	u32 control;

	u16 tx_seq;

	int len;



	chan = l2cap_get_chan_by_scid(conn, cid);

	if (!chan) {
@@ -4923,44 +4957,8 @@ static inline int l2cap_data_channel(struct l2cap_conn *conn, u16 cid, struct sk 
		break;



	case L2CAP_MODE_ERTM:

		l2cap_ertm_data_rcv(chan, skb);



		goto done;



	case L2CAP_MODE_STREAMING:

		control = __get_control(chan, skb->data);

		skb_pull(skb, __ctrl_size(chan));

		len = skb->len;



		if (l2cap_check_fcs(chan, skb))

			goto drop;



		if (__is_sar_start(chan, control))

			len -= L2CAP_SDULEN_SIZE;



		if (chan->fcs == L2CAP_FCS_CRC16)

			len -= L2CAP_FCS_SIZE;



		if (len > chan->mps || len < 0 || __is_sframe(chan, control))

			goto drop;



		tx_seq = __get_txseq(chan, control);



		if (chan->expected_tx_seq != tx_seq) {

			/* Frame(s) missing - must discard partial SDU */

			kfree_skb(chan->sdu);

			chan->sdu = NULL;

			chan->sdu_last_frag = NULL;

			chan->sdu_len = 0;



			/* TODO: Notify userland of missing data */

		}



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



		if (l2cap_reassemble_sdu(chan, skb, control) == -EMSGSIZE)

			l2cap_send_disconn_req(chan->conn, chan, ECONNRESET);



		l2cap_data_rcv(chan, skb);

		goto done;



	default: