This implements a top-level transmit state machine with handlers for
the two ERTM states defined in the specification: XMIT and WAIT_F.
The state machine accepts an event and, optionally, a list of skbs to
transmit. In addition to data transmission, the local busy state can
be modified, acks are processed, and monitor and retransmit timeouts
are handled. This mirrors the structure of the state tables in the
spec.
Signed-off-by: Mat Martineau <mathewm@xxxxxxxxxxxxxx>
---
net/bluetooth/l2cap_core.c | 254 ++++++++++++++++++++++++++++++++++++++++++--
1 file changed, 246 insertions(+), 8 deletions(-)
diff --git a/net/bluetooth/l2cap_core.c b/net/bluetooth/l2cap_core.c
index 6557367..a131403 100644
--- a/net/bluetooth/l2cap_core.c
+++ b/net/bluetooth/l2cap_core.c
@@ -73,6 +73,9 @@ static int l2cap_build_conf_req(struct l2cap_chan *chan, void *data);
static void l2cap_send_disconn_req(struct l2cap_conn *conn,
struct l2cap_chan *chan, int err);
+static int l2cap_tx(struct l2cap_chan *chan, struct l2cap_ctrl *control,
+ struct sk_buff_head *skbs, u8 event);
+
/* ---- L2CAP channels ---- */
static struct l2cap_chan *__l2cap_get_chan_by_dcid(struct l2cap_conn *conn, u16 cid)
@@ -224,6 +227,19 @@ static inline void l2cap_chan_set_err(struct l2cap_chan *chan, int err)
release_sock(sk);
}
+static struct sk_buff *l2cap_ertm_seq_in_queue(struct sk_buff_head *head,
+ u16 seq)
+{
+ struct sk_buff *skb;
+
+ skb_queue_walk(head, skb) {
+ if (bt_cb(skb)->control.txseq == seq)
+ return skb;
+ }
+
+ return NULL;
+}
+
/* ---- L2CAP sequence number lists ---- */
/* For ERTM, ordered lists of sequence numbers must be tracked for
@@ -2117,16 +2133,15 @@ int l2cap_chan_send(struct l2cap_chan *chan, struct msghdr *msg, size_t len,
if (err)
break;
- if (chan->mode == L2CAP_MODE_ERTM && chan->tx_send_head == NULL)
- chan->tx_send_head = seg_queue.next;
- skb_queue_splice_tail_init(&seg_queue, &chan->tx_q);
-
- if (chan->mode == L2CAP_MODE_ERTM)
- err = l2cap_ertm_send(chan);
- else
+ if (chan->mode == L2CAP_MODE_ERTM) {
+ err = l2cap_tx(chan, 0, &seg_queue,
+ L2CAP_EV_DATA_REQUEST);
+ } else {
+ skb_queue_splice_tail_init(&seg_queue, &chan->tx_q);
l2cap_streaming_send(chan);
+ }
- if (err >= 0)
+ if (!err)
err = len;
/* If the skbs were not queued for sending, they'll still be in
@@ -2143,6 +2158,229 @@ int l2cap_chan_send(struct l2cap_chan *chan, struct msghdr *msg, size_t len,
return err;
}
+static void l2cap_process_reqseq(struct l2cap_chan *chan, u16 reqseq)
+{
+ struct sk_buff *acked_skb;
+ u16 ackseq;
+
+ BT_DBG("chan %p, reqseq %d", chan, reqseq);
+
+ if (chan->unacked_frames == 0 || reqseq == chan->expected_ack_seq)
+ return;
+
+ BT_DBG("expected_ack_seq %d, unacked_frames %d",
+ chan->expected_ack_seq, chan->unacked_frames);
+
+ for (ackseq = chan->expected_ack_seq; ackseq != reqseq;
+ ackseq = __next_seq(chan, ackseq)) {
+
+ acked_skb = l2cap_ertm_seq_in_queue(&chan->tx_q, ackseq);
+ if (acked_skb) {
+ skb_unlink(acked_skb, &chan->tx_q);
+ kfree_skb(acked_skb);
+ chan->unacked_frames--;
+ }
+ }
+
+ chan->expected_ack_seq = reqseq;
+
+ if (chan->unacked_frames == 0)
+ __clear_retrans_timer(chan);
+
+ BT_DBG("unacked_frames %d", (int) chan->unacked_frames);
+}
+
+static void l2cap_abort_rx_srej_sent(struct l2cap_chan *chan)
+{
+ BT_DBG("chan %p", chan);
+
+ chan->expected_tx_seq = chan->buffer_seq;
+ l2cap_seq_list_clear(&chan->srej_list);
+ skb_queue_purge(&chan->srej_q);
+ chan->rx_state = L2CAP_RX_STATE_RECV;
+}
+
+static int l2cap_tx_state_xmit(struct l2cap_chan *chan,
+ struct l2cap_ctrl *control,
+ struct sk_buff_head *skbs, u8 event)
+{
+ int err = 0;
+
+ BT_DBG("chan %p, control %p, skbs %p, event %d", chan, control, skbs,
+ event);
+
+ switch (event) {
+ case L2CAP_EV_DATA_REQUEST:
+ if (chan->tx_send_head == NULL)
+ chan->tx_send_head = skb_peek(skbs);
+
+ skb_queue_splice_tail_init(skbs, &chan->tx_q);
+ l2cap_ertm_send(chan);
+ break;
+ case L2CAP_EV_LOCAL_BUSY_DETECTED:
+ BT_DBG("Enter LOCAL_BUSY");
+ set_bit(CONN_LOCAL_BUSY, &chan->conn_state);
+
+ if (chan->rx_state == L2CAP_RX_STATE_SREJ_SENT) {
+ /* The SREJ_SENT state must be aborted if we are to
+ * enter the LOCAL_BUSY state.
+ */
+ l2cap_abort_rx_srej_sent(chan);
+ }
+
+ l2cap_send_ack(chan);
+
+ break;
+ case L2CAP_EV_LOCAL_BUSY_CLEAR:
+ BT_DBG("Exit LOCAL_BUSY");
+ clear_bit(CONN_LOCAL_BUSY, &chan->conn_state);
+
+ if (test_bit(CONN_RNR_SENT, &chan->conn_state)) {
+ struct l2cap_ctrl local_control;
+
+ memset(&local_control, 0, sizeof(local_control));
+ local_control.sframe = 1;
+ local_control.super = L2CAP_SUPER_RR;
+ local_control.poll = 1;
+ local_control.reqseq = chan->buffer_seq;
