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Commit fad5fc89 authored by Johan Hedberg's avatar Johan Hedberg Committed by Marcel Holtmann
Browse files

Bluetooth: Add LE flow control discipline 



This patch adds the necessary discipline for reacting to LE L2CAP
Credits packets, sending those packets, and modifying the known credits
accordingly.

Signed-off-by: default avatarJohan Hedberg <johan.hedberg@intel.com>
Signed-off-by: default avatarMarcel Holtmann <marcel@holtmann.org>
parent b1c325c2

net/bluetooth/l2cap_core.c

+66 −1
Original line number Diff line number Diff line
@@ -2542,8 +2542,12 @@ int l2cap_chan_send(struct l2cap_chan *chan, struct msghdr *msg, size_t len, 
	}



	switch (chan->mode) {

	case L2CAP_MODE_BASIC:

	case L2CAP_MODE_LE_FLOWCTL:

		if (!chan->tx_credits)

			return -EAGAIN;



		/* fall through */

	case L2CAP_MODE_BASIC:

		/* Check outgoing MTU */

		if (len > chan->omtu)

			return -EMSGSIZE;
@@ -5551,6 +5555,42 @@ static int l2cap_le_connect_req(struct l2cap_conn *conn, 
	return 0;

}



static inline int l2cap_le_credits(struct l2cap_conn *conn,

				   struct l2cap_cmd_hdr *cmd, u16 cmd_len,

				   u8 *data)

{

	struct l2cap_le_credits *pkt;

	struct l2cap_chan *chan;

	u16 cid, credits;



	if (cmd_len != sizeof(*pkt))

		return -EPROTO;



	pkt = (struct l2cap_le_credits *) data;

	cid	= __le16_to_cpu(pkt->cid);

	credits	= __le16_to_cpu(pkt->credits);



	BT_DBG("cid 0x%4.4x credits 0x%4.4x", cid, credits);



	chan = l2cap_get_chan_by_dcid(conn, cid);

	if (!chan)

		return -EBADSLT;



	chan->tx_credits += credits;



	while (chan->tx_credits && !skb_queue_empty(&chan->tx_q)) {

		l2cap_do_send(chan, skb_dequeue(&chan->tx_q));

		chan->tx_credits--;

	}



	if (chan->tx_credits)

		chan->ops->resume(chan);



	l2cap_chan_unlock(chan);



	return 0;

}



static inline int l2cap_le_sig_cmd(struct l2cap_conn *conn,

				   struct l2cap_cmd_hdr *cmd, u16 cmd_len,

				   u8 *data)
@@ -5576,6 +5616,10 @@ static inline int l2cap_le_sig_cmd(struct l2cap_conn *conn, 
		err = l2cap_le_connect_req(conn, cmd, cmd_len, data);

		break;



	case L2CAP_LE_CREDITS:

		err = l2cap_le_credits(conn, cmd, cmd_len, data);

		break;



	case L2CAP_DISCONN_REQ:

		err = l2cap_disconnect_req(conn, cmd, cmd_len, data);

		break;
@@ -6636,6 +6680,22 @@ static void l2cap_chan_le_send_credits(struct l2cap_chan *chan) 
	l2cap_send_cmd(conn, chan->ident, L2CAP_LE_CREDITS, sizeof(pkt), &pkt);

}



static int l2cap_le_data_rcv(struct l2cap_chan *chan, struct sk_buff *skb)

{

	if (!chan->rx_credits)

		return -ENOBUFS;



	if (chan->imtu < skb->len)

		return -ENOBUFS;



	chan->rx_credits--;

	BT_DBG("rx_credits %u -> %u", chan->rx_credits + 1, chan->rx_credits);



	l2cap_chan_le_send_credits(chan);



	return chan->ops->recv(chan, skb);

}



static void l2cap_data_channel(struct l2cap_conn *conn, u16 cid,

			       struct sk_buff *skb)

{
@@ -6666,6 +6726,11 @@ static void l2cap_data_channel(struct l2cap_conn *conn, u16 cid, 


	switch (chan->mode) {

	case L2CAP_MODE_LE_FLOWCTL:

		if (l2cap_le_data_rcv(chan, skb) < 0)

			goto drop;



		goto done;



	case L2CAP_MODE_BASIC:

		/* If socket recv buffers overflows we drop data here

		 * which is *bad* because L2CAP has to be reliable.