Bluetooth: Remove double check for BT_CONNECTED
[profile/ivi/kernel-adaptation-intel-automotive.git] / net / bluetooth / l2cap_core.c
index 24f144b..5bf8287 100644 (file)
@@ -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 +227,37 @@ static inline void l2cap_chan_set_err(struct l2cap_chan *chan, int err)
        release_sock(sk);
 }
 
+static void __set_retrans_timer(struct l2cap_chan *chan)
+{
+       if (!delayed_work_pending(&chan->monitor_timer) &&
+           chan->retrans_timeout) {
+               l2cap_set_timer(chan, &chan->retrans_timer,
+                               msecs_to_jiffies(chan->retrans_timeout));
+       }
+}
+
+static void __set_monitor_timer(struct l2cap_chan *chan)
+{
+       __clear_retrans_timer(chan);
+       if (chan->monitor_timeout) {
+               l2cap_set_timer(chan, &chan->monitor_timer,
+                               msecs_to_jiffies(chan->monitor_timeout));
+       }
+}
+
+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
@@ -392,6 +426,9 @@ struct l2cap_chan *l2cap_chan_create(void)
 
        atomic_set(&chan->refcnt, 1);
 
+       /* This flag is cleared in l2cap_chan_ready() */
+       set_bit(CONF_NOT_COMPLETE, &chan->conf_state);
+
        BT_DBG("chan %p", chan);
 
        return chan;
@@ -509,15 +546,14 @@ static void l2cap_chan_del(struct l2cap_chan *chan, int err)
 
        release_sock(sk);
 
-       if (!(test_bit(CONF_OUTPUT_DONE, &chan->conf_state) &&
-                       test_bit(CONF_INPUT_DONE, &chan->conf_state)))
+       if (test_bit(CONF_NOT_COMPLETE, &chan->conf_state))
                return;
 
-       skb_queue_purge(&chan->tx_q);
-
-       if (chan->mode == L2CAP_MODE_ERTM) {
-               struct srej_list *l, *tmp;
+       switch(chan->mode) {
+       case L2CAP_MODE_BASIC:
+               break;
 
+       case L2CAP_MODE_ERTM:
                __clear_retrans_timer(chan);
                __clear_monitor_timer(chan);
                __clear_ack_timer(chan);
@@ -526,11 +562,15 @@ static void l2cap_chan_del(struct l2cap_chan *chan, int err)
 
                l2cap_seq_list_free(&chan->srej_list);
                l2cap_seq_list_free(&chan->retrans_list);
-               list_for_each_entry_safe(l, tmp, &chan->srej_l, list) {
-                       list_del(&l->list);
-                       kfree(l);
-               }
+
+               /* fall through */
+
+       case L2CAP_MODE_STREAMING:
+               skb_queue_purge(&chan->tx_q);
+               break;
        }
+
+       return;
 }
 
 static void l2cap_chan_cleanup_listen(struct sock *parent)
@@ -773,9 +813,11 @@ 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);
        }
 }
 
@@ -830,15 +872,12 @@ static inline void __pack_control(struct l2cap_chan *chan,
        }
 }
 
-static inline void l2cap_send_sframe(struct l2cap_chan *chan, u32 control)
+static struct sk_buff *l2cap_create_sframe_pdu(struct l2cap_chan *chan,
+                                              u32 control)
 {
        struct sk_buff *skb;
        struct l2cap_hdr *lh;
-       struct l2cap_conn *conn = chan->conn;
-       int count, hlen;
-
-       if (chan->state != BT_CONNECTED)
-               return;
+       int hlen;
 
        if (test_bit(FLAG_EXT_CTRL, &chan->flags))
                hlen = L2CAP_EXT_HDR_SIZE;
@@ -848,48 +887,84 @@ static inline void l2cap_send_sframe(struct l2cap_chan *chan, u32 control)
        if (chan->fcs == L2CAP_FCS_CRC16)
                hlen += L2CAP_FCS_SIZE;
 
-       BT_DBG("chan %p, control 0x%8.8x", chan, control);
-
-       count = min_t(unsigned int, conn->mtu, hlen);
+       skb = bt_skb_alloc(hlen, GFP_KERNEL);
 
-       control |= __set_sframe(chan);
-
-       if (test_and_clear_bit(CONN_SEND_FBIT, &chan->conn_state))
-               control |= __set_ctrl_final(chan);
-
-       if (test_and_clear_bit(CONN_SEND_PBIT, &chan->conn_state))
-               control |= __set_ctrl_poll(chan);
-
-       skb = bt_skb_alloc(count, GFP_ATOMIC);
        if (!skb)
-               return;
+               return ERR_PTR(-ENOMEM);
 
        lh = (struct l2cap_hdr *) skb_put(skb, L2CAP_HDR_SIZE);
        lh->len = cpu_to_le16(hlen - L2CAP_HDR_SIZE);
        lh->cid = cpu_to_le16(chan->dcid);
 
-       __put_control(chan, control, skb_put(skb, __ctrl_size(chan)));
+       if (test_bit(FLAG_EXT_CTRL, &chan->flags))
+               put_unaligned_le32(control, skb_put(skb, L2CAP_EXT_CTRL_SIZE));
+       else
+               put_unaligned_le16(control, skb_put(skb, L2CAP_ENH_CTRL_SIZE));
 
        if (chan->fcs == L2CAP_FCS_CRC16) {
-               u16 fcs = crc16(0, (u8 *)lh, count - L2CAP_FCS_SIZE);
+               u16 fcs = crc16(0, (u8 *)skb->data, skb->len);
                put_unaligned_le16(fcs, skb_put(skb, L2CAP_FCS_SIZE));
        }
 
        skb->priority = HCI_PRIO_MAX;
-       l2cap_do_send(chan, skb);
+       return skb;
 }
 
-static inline void l2cap_send_rr_or_rnr(struct l2cap_chan *chan, u32 control)
+static void l2cap_send_sframe(struct l2cap_chan *chan,
+                             struct l2cap_ctrl *control)
 {
-       if (test_bit(CONN_LOCAL_BUSY, &chan->conn_state)) {
-               control |= __set_ctrl_super(chan, L2CAP_SUPER_RNR);
+       struct sk_buff *skb;
+       u32 control_field;
+
+       BT_DBG("chan %p, control %p", chan, control);
+
+       if (!control->sframe)
+               return;
+
+       if (test_and_clear_bit(CONN_SEND_FBIT, &chan->conn_state) &&
+           !control->poll)
+               control->final = 1;
+
+       if (control->super == L2CAP_SUPER_RR)
+               clear_bit(CONN_RNR_SENT, &chan->conn_state);
+       else if (control->super == L2CAP_SUPER_RNR)
                set_bit(CONN_RNR_SENT, &chan->conn_state);
-       } else
-               control |= __set_ctrl_super(chan, L2CAP_SUPER_RR);
 
-       control |= __set_reqseq(chan, chan->buffer_seq);
+       if (control->super != L2CAP_SUPER_SREJ) {
+               chan->last_acked_seq = control->reqseq;
+               __clear_ack_timer(chan);
+       }
+
+       BT_DBG("reqseq %d, final %d, poll %d, super %d", control->reqseq,
+              control->final, control->poll, control->super);
+
+       if (test_bit(FLAG_EXT_CTRL, &chan->flags))
+               control_field = __pack_extended_control(control);
+       else
+               control_field = __pack_enhanced_control(control);
+
+       skb = l2cap_create_sframe_pdu(chan, control_field);
+       if (!IS_ERR(skb))
+               l2cap_do_send(chan, skb);
+}
+
+static void l2cap_send_rr_or_rnr(struct l2cap_chan *chan, bool poll)
+{
+       struct l2cap_ctrl control;
+
+       BT_DBG("chan %p, poll %d", chan, poll);
 
-       l2cap_send_sframe(chan, control);
+       memset(&control, 0, sizeof(control));
+       control.sframe = 1;
+       control.poll = poll;
+
+       if (test_bit(CONN_LOCAL_BUSY, &chan->conn_state))
+               control.super = L2CAP_SUPER_RNR;
+       else
+               control.super = L2CAP_SUPER_RR;
+
+       control.reqseq = chan->buffer_seq;
+       l2cap_send_sframe(chan, &control);
 }
 
 static inline int __l2cap_no_conn_pending(struct l2cap_chan *chan)
@@ -923,6 +998,7 @@ static void l2cap_chan_ready(struct l2cap_chan *chan)
 
        BT_DBG("sk %p, parent %p", sk, parent);
 
+       /* This clears all conf flags, including CONF_NOT_COMPLETE */
        chan->conf_state = 0;
        __clear_chan_timer(chan);
 
@@ -1571,23 +1647,20 @@ int __l2cap_wait_ack(struct sock *sk)
 static void l2cap_monitor_timeout(struct work_struct *work)
 {
        struct l2cap_chan *chan = container_of(work, struct l2cap_chan,
-                                                       monitor_timer.work);
+                                              monitor_timer.work);
 
        BT_DBG("chan %p", chan);
 
        l2cap_chan_lock(chan);
 
-       if (chan->retry_count >= chan->remote_max_tx) {
-               l2cap_send_disconn_req(chan->conn, chan, ECONNABORTED);
+       if (!chan->conn) {
                l2cap_chan_unlock(chan);
                l2cap_chan_put(chan);
                return;
        }
 
-       chan->retry_count++;
-       __set_monitor_timer(chan);
+       l2cap_tx(chan, NULL, NULL, L2CAP_EV_MONITOR_TO);
 
-       l2cap_send_rr_or_rnr(chan, L2CAP_CTRL_POLL);
        l2cap_chan_unlock(chan);
        l2cap_chan_put(chan);
 }
@@ -1595,234 +1668,295 @@ static void l2cap_monitor_timeout(struct work_struct *work)
 static void l2cap_retrans_timeout(struct work_struct *work)
 {
        struct l2cap_chan *chan = container_of(work, struct l2cap_chan,
-                                                       retrans_timer.work);
+                                              retrans_timer.work);
 
        BT_DBG("chan %p", chan);
 
        l2cap_chan_lock(chan);
 
-       chan->retry_count = 1;
-       __set_monitor_timer(chan);
-
-       set_bit(CONN_WAIT_F, &chan->conn_state);
-
-       l2cap_send_rr_or_rnr(chan, L2CAP_CTRL_POLL);
+       if (!chan->conn) {
+               l2cap_chan_unlock(chan);
+               l2cap_chan_put(chan);
+               return;
+       }
 
+       l2cap_tx(chan, NULL, NULL, L2CAP_EV_RETRANS_TO);
        l2cap_chan_unlock(chan);
        l2cap_chan_put(chan);
 }
 
-static void l2cap_drop_acked_frames(struct l2cap_chan *chan)
+static int l2cap_streaming_send(struct l2cap_chan *chan,
+                               struct sk_buff_head *skbs)
 {
        struct sk_buff *skb;
+       struct l2cap_ctrl *control;
 
-       while ((skb = skb_peek(&chan->tx_q)) &&
-                       chan->unacked_frames) {
-               if (bt_cb(skb)->control.txseq == chan->expected_ack_seq)
-                       break;
+       BT_DBG("chan %p, skbs %p", chan, skbs);
 
-               skb = skb_dequeue(&chan->tx_q);
-               kfree_skb(skb);
+       skb_queue_splice_tail_init(skbs, &chan->tx_q);
 
-               chan->unacked_frames--;
-       }
+       while (!skb_queue_empty(&chan->tx_q)) {
 
-       if (!chan->unacked_frames)
-               __clear_retrans_timer(chan);
-}
+               skb = skb_dequeue(&chan->tx_q);
 
-static void l2cap_streaming_send(struct l2cap_chan *chan)
-{
-       struct sk_buff *skb;
-       u32 control;
-       u16 fcs;
+               bt_cb(skb)->control.retries = 1;
+               control = &bt_cb(skb)->control;
 
-       while ((skb = skb_dequeue(&chan->tx_q))) {
-               control = __get_control(chan, skb->data + L2CAP_HDR_SIZE);
-               control |= __set_txseq(chan, chan->next_tx_seq);
-               control |= __set_ctrl_sar(chan, bt_cb(skb)->control.sar);
-               __put_control(chan, control, skb->data + L2CAP_HDR_SIZE);
+               control->reqseq = 0;
+               control->txseq = chan->next_tx_seq;
+
+               __pack_control(chan, control, skb);
 
                if (chan->fcs == L2CAP_FCS_CRC16) {
-                       fcs = crc16(0, (u8 *)skb->data,
-                                               skb->len - L2CAP_FCS_SIZE);
-                       put_unaligned_le16(fcs,
-                                       skb->data + skb->len - L2CAP_FCS_SIZE);
+                       u16 fcs = crc16(0, (u8 *) skb->data, skb->len);
+                       put_unaligned_le16(fcs, skb_put(skb, L2CAP_FCS_SIZE));
                }
 
                l2cap_do_send(chan, skb);
 
+               BT_DBG("Sent txseq %d", (int)control->txseq);
+
                chan->next_tx_seq = __next_seq(chan, chan->next_tx_seq);
+               chan->frames_sent++;
        }
+
+       return 0;
 }
 
-static void l2cap_retransmit_one_frame(struct l2cap_chan *chan, u16 tx_seq)
+static int l2cap_ertm_send(struct l2cap_chan *chan)
 {
        struct sk_buff *skb, *tx_skb;
-       u16 fcs;
-       u32 control;
+       struct l2cap_ctrl *control;
+       int sent = 0;
 
-       skb = skb_peek(&chan->tx_q);
-       if (!skb)
-               return;
+       BT_DBG("chan %p", chan);
 
-       while (bt_cb(skb)->control.txseq != tx_seq) {
-               if (skb_queue_is_last(&chan->tx_q, skb))
-                       return;
+       if (chan->state != BT_CONNECTED)
+               return -ENOTCONN;
 
-               skb = skb_queue_next(&chan->tx_q, skb);
-       }
+       if (test_bit(CONN_REMOTE_BUSY, &chan->conn_state))
+               return 0;
 
-       if (bt_cb(skb)->control.retries == chan->remote_max_tx &&
-           chan->remote_max_tx) {
-               l2cap_send_disconn_req(chan->conn, chan, ECONNABORTED);
-               return;
-       }
+       while (chan->tx_send_head &&
+              chan->unacked_frames < chan->remote_tx_win &&
+              chan->tx_state == L2CAP_TX_STATE_XMIT) {
 
-       tx_skb = skb_clone(skb, GFP_ATOMIC);
-       bt_cb(skb)->control.retries++;
+               skb = chan->tx_send_head;
 
-       control = __get_control(chan, tx_skb->data + L2CAP_HDR_SIZE);
-       control &= __get_sar_mask(chan);
+               bt_cb(skb)->control.retries = 1;
+               control = &bt_cb(skb)->control;
 
-       if (test_and_clear_bit(CONN_SEND_FBIT, &chan->conn_state))
-               control |= __set_ctrl_final(chan);
+               if (test_and_clear_bit(CONN_SEND_FBIT, &chan->conn_state))
+                       control->final = 1;
 
-       control |= __set_reqseq(chan, chan->buffer_seq);
-       control |= __set_txseq(chan, tx_seq);
+               control->reqseq = chan->buffer_seq;
+               chan->last_acked_seq = chan->buffer_seq;
+               control->txseq = chan->next_tx_seq;
 
-       __put_control(chan, control, tx_skb->data + L2CAP_HDR_SIZE);
+               __pack_control(chan, control, skb);
 
-       if (chan->fcs == L2CAP_FCS_CRC16) {
-               fcs = crc16(0, (u8 *)tx_skb->data,
-                                               tx_skb->len - L2CAP_FCS_SIZE);
-               put_unaligned_le16(fcs,
-                               tx_skb->data + tx_skb->len - L2CAP_FCS_SIZE);
+               if (chan->fcs == L2CAP_FCS_CRC16) {
+                       u16 fcs = crc16(0, (u8 *) skb->data, skb->len);
+                       put_unaligned_le16(fcs, skb_put(skb, L2CAP_FCS_SIZE));
+               }
+
+               /* Clone after data has been modified. Data is assumed to be
+                  read-only (for locking purposes) on cloned sk_buffs.
+                */
+               tx_skb = skb_clone(skb, GFP_KERNEL);
+
+               if (!tx_skb)
+                       break;
+
+               __set_retrans_timer(chan);
+
+               chan->next_tx_seq = __next_seq(chan, chan->next_tx_seq);
+               chan->unacked_frames++;
+               chan->frames_sent++;
+               sent++;
+
+               if (skb_queue_is_last(&chan->tx_q, skb))
+                       chan->tx_send_head = NULL;
+               else
+                       chan->tx_send_head = skb_queue_next(&chan->tx_q, skb);
+
+               l2cap_do_send(chan, tx_skb);
+               BT_DBG("Sent txseq %d", (int)control->txseq);
        }
 
-       l2cap_do_send(chan, tx_skb);
+       BT_DBG("Sent %d, %d unacked, %d in ERTM queue", sent,
+              (int) chan->unacked_frames, skb_queue_len(&chan->tx_q));
+
+       return sent;
 }
 
-static int l2cap_ertm_send(struct l2cap_chan *chan)
+static void l2cap_ertm_resend(struct l2cap_chan *chan)
 {
-       struct sk_buff *skb, *tx_skb;
-       u16 fcs;
-       u32 control;
-       int nsent = 0;
+       struct l2cap_ctrl control;
+       struct sk_buff *skb;
+       struct sk_buff *tx_skb;
+       u16 seq;
 
-       if (chan->state != BT_CONNECTED)
-               return -ENOTCONN;
+       BT_DBG("chan %p", chan);
 
        if (test_bit(CONN_REMOTE_BUSY, &chan->conn_state))
-               return 0;
+               return;
 
-       while ((skb = chan->tx_send_head) && (!l2cap_tx_window_full(chan))) {
+       while (chan->retrans_list.head != L2CAP_SEQ_LIST_CLEAR) {
+               seq = l2cap_seq_list_pop(&chan->retrans_list);
 
-               if (bt_cb(skb)->control.retries == chan->remote_max_tx &&
-                   chan->remote_max_tx) {
-                       l2cap_send_disconn_req(chan->conn, chan, ECONNABORTED);
-                       break;
+               skb = l2cap_ertm_seq_in_queue(&chan->tx_q, seq);
+               if (!skb) {
+                       BT_DBG("Error: Can't retransmit seq %d, frame missing",
+                               seq);
+                       continue;
                }
 
-               tx_skb = skb_clone(skb, GFP_ATOMIC);
-
                bt_cb(skb)->control.retries++;
+               control = bt_cb(skb)->control;
 
-               control = __get_control(chan, tx_skb->data + L2CAP_HDR_SIZE);
-               control &= __get_sar_mask(chan);
+               if (chan->max_tx != 0 &&
+                   bt_cb(skb)->control.retries > chan->max_tx) {
+                       BT_DBG("Retry limit exceeded (%d)", chan->max_tx);
+                       l2cap_send_disconn_req(chan->conn, chan, ECONNRESET);
+                       l2cap_seq_list_clear(&chan->retrans_list);
+                       break;
+               }
 
+               control.reqseq = chan->buffer_seq;
                if (test_and_clear_bit(CONN_SEND_FBIT, &chan->conn_state))
-                       control |= __set_ctrl_final(chan);
+                       control.final = 1;
+               else
+                       control.final = 0;
+
+               if (skb_cloned(skb)) {
+                       /* Cloned sk_buffs are read-only, so we need a
+                        * writeable copy
+                        */
+                       tx_skb = skb_copy(skb, GFP_ATOMIC);
+               } else {
+                       tx_skb = skb_clone(skb, GFP_ATOMIC);
+               }
 
-               control |= __set_reqseq(chan, chan->buffer_seq);
-               control |= __set_txseq(chan, chan->next_tx_seq);
-               control |= __set_ctrl_sar(chan, bt_cb(skb)->control.sar);
+               if (!tx_skb) {
+                       l2cap_seq_list_clear(&chan->retrans_list);
+                       break;
+               }
 
-               __put_control(chan, control, tx_skb->data + L2CAP_HDR_SIZE);
+               /* Update skb contents */
+               if (test_bit(FLAG_EXT_CTRL, &chan->flags)) {
+                       put_unaligned_le32(__pack_extended_control(&control),
+                                          tx_skb->data + L2CAP_HDR_SIZE);
+               } else {
+                       put_unaligned_le16(__pack_enhanced_control(&control),
+                                          tx_skb->data + L2CAP_HDR_SIZE);
+               }
 
                if (chan->fcs == L2CAP_FCS_CRC16) {
-                       fcs = crc16(0, (u8 *)skb->data,
-                                               tx_skb->len - L2CAP_FCS_SIZE);
-                       put_unaligned_le16(fcs, skb->data +
-                                               tx_skb->len - L2CAP_FCS_SIZE);
+                       u16 fcs = crc16(0, (u8 *) tx_skb->data, tx_skb->len);
+                       put_unaligned_le16(fcs, skb_put(tx_skb,
+                                                       L2CAP_FCS_SIZE));
                }
 
                l2cap_do_send(chan, tx_skb);
 
-               __set_retrans_timer(chan);
-
-               bt_cb(skb)->control.txseq = chan->next_tx_seq;
-
-               chan->next_tx_seq = __next_seq(chan, chan->next_tx_seq);
-
-               if (bt_cb(skb)->control.retries == 1) {
-                       chan->unacked_frames++;
-
-                       if (!nsent++)
-                               __clear_ack_timer(chan);
-               }
-
-               chan->frames_sent++;
+               BT_DBG("Resent txseq %d", control.txseq);
 
-               if (skb_queue_is_last(&chan->tx_q, skb))
-                       chan->tx_send_head = NULL;
-               else
-                       chan->tx_send_head = skb_queue_next(&chan->tx_q, skb);
+               chan->last_acked_seq = chan->buffer_seq;
        }
-
-       return nsent;
 }
 
-static int l2cap_retransmit_frames(struct l2cap_chan *chan)
+static void l2cap_retransmit(struct l2cap_chan *chan,
+                            struct l2cap_ctrl *control)
 {
-       int ret;
+       BT_DBG("chan %p, control %p", chan, control);
 
-       if (!skb_queue_empty(&chan->tx_q))
-               chan->tx_send_head = chan->tx_q.next;
-
-       chan->next_tx_seq = chan->expected_ack_seq;
-       ret = l2cap_ertm_send(chan);
-       return ret;
+       l2cap_seq_list_append(&chan->retrans_list, control->reqseq);
+       l2cap_ertm_resend(chan);
 }
 
-static void __l2cap_send_ack(struct l2cap_chan *chan)
+static void l2cap_retransmit_all(struct l2cap_chan *chan,
+                                struct l2cap_ctrl *control)
 {
-       u32 control = 0;
+       struct sk_buff *skb;
 
-       control |= __set_reqseq(chan, chan->buffer_seq);
+       BT_DBG("chan %p, control %p", chan, control);
 
-       if (test_bit(CONN_LOCAL_BUSY, &chan->conn_state)) {
-               control |= __set_ctrl_super(chan, L2CAP_SUPER_RNR);
-               set_bit(CONN_RNR_SENT, &chan->conn_state);
-               l2cap_send_sframe(chan, control);
-               return;
-       }
+       if (control->poll)
+               set_bit(CONN_SEND_FBIT, &chan->conn_state);
+
+       l2cap_seq_list_clear(&chan->retrans_list);
 
-       if (l2cap_ertm_send(chan) > 0)
+       if (test_bit(CONN_REMOTE_BUSY, &chan->conn_state))
                return;
 
-       control |= __set_ctrl_super(chan, L2CAP_SUPER_RR);
-       l2cap_send_sframe(chan, control);
+       if (chan->unacked_frames) {
+               skb_queue_walk(&chan->tx_q, skb) {
+                       if (bt_cb(skb)->control.txseq == control->reqseq ||
+                               skb == chan->tx_send_head)
+                               break;
+               }
+
+               skb_queue_walk_from(&chan->tx_q, skb) {
+                       if (skb == chan->tx_send_head)
+                               break;
+
+                       l2cap_seq_list_append(&chan->retrans_list,
+                                             bt_cb(skb)->control.txseq);
+               }
+
+               l2cap_ertm_resend(chan);
+       }
 }
 
 static void l2cap_send_ack(struct l2cap_chan *chan)
 {
-       __clear_ack_timer(chan);
-       __l2cap_send_ack(chan);
-}
+       struct l2cap_ctrl control;
+       u16 frames_to_ack = __seq_offset(chan, chan->buffer_seq,
+                                        chan->last_acked_seq);
+       int threshold;
 
-static void l2cap_send_srejtail(struct l2cap_chan *chan)
-{
-       struct srej_list *tail;
-       u32 control;
+       BT_DBG("chan %p last_acked_seq %d buffer_seq %d",
+              chan, chan->last_acked_seq, chan->buffer_seq);
+
+       memset(&control, 0, sizeof(control));
+       control.sframe = 1;
 
-       control = __set_ctrl_super(chan, L2CAP_SUPER_SREJ);
-       control |= __set_ctrl_final(chan);
+       if (test_bit(CONN_LOCAL_BUSY, &chan->conn_state) &&
+           chan->rx_state == L2CAP_RX_STATE_RECV) {
+               __clear_ack_timer(chan);
+               control.super = L2CAP_SUPER_RNR;
+               control.reqseq = chan->buffer_seq;
+               l2cap_send_sframe(chan, &control);
+       } else {
+               if (!test_bit(CONN_REMOTE_BUSY, &chan->conn_state)) {
+                       l2cap_ertm_send(chan);
+                       /* If any i-frames were sent, they included an ack */
+                       if (chan->buffer_seq == chan->last_acked_seq)
+                               frames_to_ack = 0;
+               }
 
-       tail = list_entry((&chan->srej_l)->prev, struct srej_list, list);
-       control |= __set_reqseq(chan, tail->tx_seq);
+               /* Ack now if the tx window is 3/4ths full.
+                * Calculate without mul or div
+                */
+               threshold = chan->tx_win;
+               threshold += threshold << 1;
+               threshold >>= 2;
+
+               BT_DBG("frames_to_ack %d, threshold %d", (int)frames_to_ack,
+                      threshold);
+
+               if (frames_to_ack >= threshold) {
+                       __clear_ack_timer(chan);
+                       control.super = L2CAP_SUPER_RR;
+                       control.reqseq = chan->buffer_seq;
+                       l2cap_send_sframe(chan, &control);
+                       frames_to_ack = 0;
+               }
 
-       l2cap_send_sframe(chan, control);
+               if (frames_to_ack)
+                       __set_ack_timer(chan);
+       }
 }
 
 static inline int l2cap_skbuff_fromiovec(struct l2cap_chan *chan,
@@ -1974,7 +2108,11 @@ static struct sk_buff *l2cap_create_iframe_pdu(struct l2cap_chan *chan,
        lh->cid = cpu_to_le16(chan->dcid);
        lh->len = cpu_to_le16(len + (hlen - L2CAP_HDR_SIZE));
 
-       __put_control(chan, 0, skb_put(skb, __ctrl_size(chan)));
+       /* Control header is populated later */
+       if (test_bit(FLAG_EXT_CTRL, &chan->flags))
+               put_unaligned_le32(0, skb_put(skb, L2CAP_EXT_CTRL_SIZE));
+       else
+               put_unaligned_le16(0, skb_put(skb, L2CAP_ENH_CTRL_SIZE));
 
        if (sdulen)
                put_unaligned_le16(sdulen, skb_put(skb, L2CAP_SDULEN_SIZE));
@@ -1985,9 +2123,7 @@ static struct sk_buff *l2cap_create_iframe_pdu(struct l2cap_chan *chan,
                return ERR_PTR(err);
        }
 
-       if (chan->fcs == L2CAP_FCS_CRC16)
-               put_unaligned_le16(0, skb_put(skb, L2CAP_FCS_SIZE));
-
+       bt_cb(skb)->control.fcs = chan->fcs;
        bt_cb(skb)->control.retries = 0;
        return skb;
 }
@@ -2117,16 +2253,13 @@ 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);
+                       err = l2cap_tx(chan, NULL, &seg_queue,
+                                      L2CAP_EV_DATA_REQUEST);
                else
-                       l2cap_streaming_send(chan);
+                       err = l2cap_streaming_send(chan, &seg_queue);
 
-               if (err >= 0)
+               if (!err)
                        err = len;
 
                /* If the skbs were not queued for sending, they'll still be in
@@ -2143,82 +2276,384 @@ int l2cap_chan_send(struct l2cap_chan *chan, struct msghdr *msg, size_t len,
        return err;
 }
 
-/* Copy frame to all raw sockets on that connection */
-static void l2cap_raw_recv(struct l2cap_conn *conn, struct sk_buff *skb)
+static void l2cap_send_srej(struct l2cap_chan *chan, u16 txseq)
 {
-       struct sk_buff *nskb;
-       struct l2cap_chan *chan;
-
-       BT_DBG("conn %p", conn);
-
-       mutex_lock(&conn->chan_lock);
+       struct l2cap_ctrl control;
+       u16 seq;
 
-       list_for_each_entry(chan, &conn->chan_l, list) {
-               struct sock *sk = chan->sk;
-               if (chan->chan_type != L2CAP_CHAN_RAW)
-                       continue;
+       BT_DBG("chan %p, txseq %d", chan, txseq);
 
-               /* Don't send frame to the socket it came from */
-               if (skb->sk == sk)
-                       continue;
-               nskb = skb_clone(skb, GFP_ATOMIC);
-               if (!nskb)
-                       continue;
+       memset(&control, 0, sizeof(control));
+       control.sframe = 1;
+       control.super = L2CAP_SUPER_SREJ;
 
-               if (chan->ops->recv(chan->data, nskb))
-                       kfree_skb(nskb);
+       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);
+               }
        }
 
-       mutex_unlock(&conn->chan_lock);
+       chan->expected_tx_seq = __next_seq(chan, txseq);
 }
 
-/* ---- L2CAP signalling commands ---- */
-static struct sk_buff *l2cap_build_cmd(struct l2cap_conn *conn,
-                               u8 code, u8 ident, u16 dlen, void *data)
+static void l2cap_send_srej_tail(struct l2cap_chan *chan)
 {
-       struct sk_buff *skb, **frag;
-       struct l2cap_cmd_hdr *cmd;
-       struct l2cap_hdr *lh;
-       int len, count;
+       struct l2cap_ctrl control;
 
-       BT_DBG("conn %p, code 0x%2.2x, ident 0x%2.2x, len %d",
-                       conn, code, ident, dlen);
+       BT_DBG("chan %p", chan);
 
-       len = L2CAP_HDR_SIZE + L2CAP_CMD_HDR_SIZE + dlen;
-       count = min_t(unsigned int, conn->mtu, len);
+       if (chan->srej_list.tail == L2CAP_SEQ_LIST_CLEAR)
+               return;
 
-       skb = bt_skb_alloc(count, GFP_ATOMIC);
-       if (!skb)
-               return NULL;
+       memset(&control, 0, sizeof(control));
+       control.sframe = 1;
+       control.super = L2CAP_SUPER_SREJ;
+       control.reqseq = chan->srej_list.tail;
+       l2cap_send_sframe(chan, &control);
+}
 
-       lh = (struct l2cap_hdr *) skb_put(skb, L2CAP_HDR_SIZE);
-       lh->len = cpu_to_le16(L2CAP_CMD_HDR_SIZE + dlen);
+static void l2cap_send_srej_list(struct l2cap_chan *chan, u16 txseq)
+{
+       struct l2cap_ctrl control;
+       u16 initial_head;
+       u16 seq;
 
-       if (conn->hcon->type == LE_LINK)
-               lh->cid = cpu_to_le16(L2CAP_CID_LE_SIGNALING);
-       else
-               lh->cid = cpu_to_le16(L2CAP_CID_SIGNALING);
+       BT_DBG("chan %p, txseq %d", chan, txseq);
 
-       cmd = (struct l2cap_cmd_hdr *) skb_put(skb, L2CAP_CMD_HDR_SIZE);
-       cmd->code  = code;
-       cmd->ident = ident;
-       cmd->len   = cpu_to_le16(dlen);
+       memset(&control, 0, sizeof(control));
+       control.sframe = 1;
+       control.super = L2CAP_SUPER_SREJ;
 
-       if (dlen) {
-               count -= L2CAP_HDR_SIZE + L2CAP_CMD_HDR_SIZE;
-               memcpy(skb_put(skb, count), data, count);
-               data += count;
-       }
+       /* Capture initial list head to allow only one pass through the list. */
+       initial_head = chan->srej_list.head;
 
-       len -= skb->len;
+       do {
+               seq = l2cap_seq_list_pop(&chan->srej_list);
+               if (seq == txseq || seq == L2CAP_SEQ_LIST_CLEAR)
+                       break;
 
-       /* Continuation fragments (no L2CAP header) */
-       frag = &skb_shinfo(skb)->frag_list;
-       while (len) {
-               count = min_t(unsigned int, conn->mtu, len);
+               control.reqseq = seq;
+               l2cap_send_sframe(chan, &control);
+               l2cap_seq_list_append(&chan->srej_list, seq);
+       } while (chan->srej_list.head != initial_head);
+}
 
-               *frag = bt_skb_alloc(count, GFP_ATOMIC);
-               if (!*frag)
+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;
+                       l2cap_send_sframe(chan, &local_control);
+
+                       chan->retry_count = 1;
+                       __set_monitor_timer(chan);
+                       chan->tx_state = L2CAP_TX_STATE_WAIT_F;
+               }
+               break;
+       case L2CAP_EV_RECV_REQSEQ_AND_FBIT:
+               l2cap_process_reqseq(chan, control->reqseq);
+               break;
+       case L2CAP_EV_EXPLICIT_POLL:
+               l2cap_send_rr_or_rnr(chan, 1);
+               chan->retry_count = 1;
+               __set_monitor_timer(chan);
+               __clear_ack_timer(chan);
+               chan->tx_state = L2CAP_TX_STATE_WAIT_F;
+               break;
+       case L2CAP_EV_RETRANS_TO:
+               l2cap_send_rr_or_rnr(chan, 1);
+               chan->retry_count = 1;
+               __set_monitor_timer(chan);
+               chan->tx_state = L2CAP_TX_STATE_WAIT_F;
+               break;
+       case L2CAP_EV_RECV_FBIT:
+               /* Nothing to process */
+               break;
+       default:
+               break;
+       }
+
+       return err;
+}
+
+static int l2cap_tx_state_wait_f(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);
+               /* Queue data, but don't send. */
+               skb_queue_splice_tail_init(skbs, &chan->tx_q);
+               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;
+                       l2cap_send_sframe(chan, &local_control);
+
+                       chan->retry_count = 1;
+                       __set_monitor_timer(chan);
+                       chan->tx_state = L2CAP_TX_STATE_WAIT_F;
+               }
+               break;
+       case L2CAP_EV_RECV_REQSEQ_AND_FBIT:
+               l2cap_process_reqseq(chan, control->reqseq);
+
+               /* Fall through */
+
+       case L2CAP_EV_RECV_FBIT:
+               if (control && control->final) {
+                       __clear_monitor_timer(chan);
+                       if (chan->unacked_frames > 0)
+                               __set_retrans_timer(chan);
+                       chan->retry_count = 0;
+                       chan->tx_state = L2CAP_TX_STATE_XMIT;
+                       BT_DBG("recv fbit tx_state 0x2.2%x", chan->tx_state);
+               }
+               break;
+       case L2CAP_EV_EXPLICIT_POLL:
+               /* Ignore */
+               break;
+       case L2CAP_EV_MONITOR_TO:
+               if (chan->max_tx == 0 || chan->retry_count < chan->max_tx) {
+                       l2cap_send_rr_or_rnr(chan, 1);
+                       __set_monitor_timer(chan);
+                       chan->retry_count++;
+               } else {
+                       l2cap_send_disconn_req(chan->conn, chan, ECONNABORTED);
+               }
+               break;
+       default:
+               break;
+       }
+
+       return err;
+}
+
+static int l2cap_tx(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, state %d",
+              chan, control, skbs, event, chan->tx_state);
+
+       switch (chan->tx_state) {
+       case L2CAP_TX_STATE_XMIT:
+               err = l2cap_tx_state_xmit(chan, control, skbs, event);
+               break;
+       case L2CAP_TX_STATE_WAIT_F:
+               err = l2cap_tx_state_wait_f(chan, control, skbs, event);
+               break;
+       default:
+               /* Ignore event */
+               break;
+       }
+
+       return err;
+}
+
+static void l2cap_pass_to_tx(struct l2cap_chan *chan,
+                            struct l2cap_ctrl *control)
+{
+       BT_DBG("chan %p, control %p", chan, control);
+       l2cap_tx(chan, control, NULL, L2CAP_EV_RECV_REQSEQ_AND_FBIT);
+}
+
+static void l2cap_pass_to_tx_fbit(struct l2cap_chan *chan,
+                                 struct l2cap_ctrl *control)
+{
+       BT_DBG("chan %p, control %p", chan, control);
+       l2cap_tx(chan, control, NULL, L2CAP_EV_RECV_FBIT);
+}
+
+/* Copy frame to all raw sockets on that connection */
+static void l2cap_raw_recv(struct l2cap_conn *conn, struct sk_buff *skb)
+{
+       struct sk_buff *nskb;
+       struct l2cap_chan *chan;
+
+       BT_DBG("conn %p", conn);
+
+       mutex_lock(&conn->chan_lock);
+
+       list_for_each_entry(chan, &conn->chan_l, list) {
+               struct sock *sk = chan->sk;
+               if (chan->chan_type != L2CAP_CHAN_RAW)
+                       continue;
+
+               /* Don't send frame to the socket it came from */
+               if (skb->sk == sk)
+                       continue;
+               nskb = skb_clone(skb, GFP_ATOMIC);
+               if (!nskb)
+                       continue;
+
+               if (chan->ops->recv(chan->data, nskb))
+                       kfree_skb(nskb);
+       }
+
+       mutex_unlock(&conn->chan_lock);
+}
+
+/* ---- L2CAP signalling commands ---- */
+static struct sk_buff *l2cap_build_cmd(struct l2cap_conn *conn,
+                               u8 code, u8 ident, u16 dlen, void *data)
+{
+       struct sk_buff *skb, **frag;
+       struct l2cap_cmd_hdr *cmd;
+       struct l2cap_hdr *lh;
+       int len, count;
+
+       BT_DBG("conn %p, code 0x%2.2x, ident 0x%2.2x, len %d",
+                       conn, code, ident, dlen);
+
+       len = L2CAP_HDR_SIZE + L2CAP_CMD_HDR_SIZE + dlen;
+       count = min_t(unsigned int, conn->mtu, len);
+
+       skb = bt_skb_alloc(count, GFP_ATOMIC);
+       if (!skb)
+               return NULL;
+
+       lh = (struct l2cap_hdr *) skb_put(skb, L2CAP_HDR_SIZE);
+       lh->len = cpu_to_le16(L2CAP_CMD_HDR_SIZE + dlen);
+
+       if (conn->hcon->type == LE_LINK)
+               lh->cid = cpu_to_le16(L2CAP_CID_LE_SIGNALING);
+       else
+               lh->cid = cpu_to_le16(L2CAP_CID_SIGNALING);
+
+       cmd = (struct l2cap_cmd_hdr *) skb_put(skb, L2CAP_CMD_HDR_SIZE);
+       cmd->code  = code;
+       cmd->ident = ident;
+       cmd->len   = cpu_to_le16(dlen);
+
+       if (dlen) {
+               count -= L2CAP_HDR_SIZE + L2CAP_CMD_HDR_SIZE;
+               memcpy(skb_put(skb, count), data, count);
+               data += count;
+       }
+
+       len -= skb->len;
+
+       /* Continuation fragments (no L2CAP header) */
+       frag = &skb_shinfo(skb)->frag_list;
+       while (len) {
+               count = min_t(unsigned int, conn->mtu, len);
+
+               *frag = bt_skb_alloc(count, GFP_ATOMIC);
+               if (!*frag)
                        goto fail;
 
                memcpy(skb_put(*frag, count), data, count);
@@ -2333,16 +2768,20 @@ static void l2cap_add_opt_efs(void **ptr, struct l2cap_chan *chan)
 static void l2cap_ack_timeout(struct work_struct *work)
 {
        struct l2cap_chan *chan = container_of(work, struct l2cap_chan,
-                                                       ack_timer.work);
+                                              ack_timer.work);
+       u16 frames_to_ack;
 
        BT_DBG("chan %p", chan);
 
        l2cap_chan_lock(chan);
 
-       __l2cap_send_ack(chan);
+       frames_to_ack = __seq_offset(chan, chan->buffer_seq,
+                                    chan->last_acked_seq);
 
-       l2cap_chan_unlock(chan);
+       if (frames_to_ack)
+               l2cap_send_rr_or_rnr(chan, 0);
 
+       l2cap_chan_unlock(chan);
        l2cap_chan_put(chan);
 }
 
@@ -2355,7 +2794,6 @@ static inline int l2cap_ertm_init(struct l2cap_chan *chan)
        chan->expected_ack_seq = 0;
        chan->unacked_frames = 0;
        chan->buffer_seq = 0;
-       chan->num_acked = 0;
        chan->frames_sent = 0;
        chan->last_acked_seq = 0;
        chan->sdu = NULL;
@@ -2376,12 +2814,15 @@ static inline int l2cap_ertm_init(struct l2cap_chan *chan)
 
        skb_queue_head_init(&chan->srej_q);
 
-       INIT_LIST_HEAD(&chan->srej_l);
        err = l2cap_seq_list_init(&chan->srej_list, chan->tx_win);
        if (err < 0)
                return err;
 
-       return l2cap_seq_list_init(&chan->retrans_list, chan->remote_tx_win);
+       err = l2cap_seq_list_init(&chan->retrans_list, chan->remote_tx_win);
+       if (err < 0)
+               l2cap_seq_list_free(&chan->srej_list);
+
+       return err;
 }
 
 static inline __u8 l2cap_select_mode(__u8 mode, __u16 remote_feat_mask)
@@ -2507,6 +2948,7 @@ done:
                break;
 
        case L2CAP_MODE_STREAMING:
+               l2cap_txwin_setup(chan);
                rfc.mode            = L2CAP_MODE_STREAMING;
                rfc.txwin_size      = 0;
                rfc.max_transmit    = 0;
@@ -3965,67 +4407,40 @@ static int l2cap_check_fcs(struct l2cap_chan *chan,  struct sk_buff *skb)
        return 0;
 }
 
-static inline void l2cap_send_i_or_rr_or_rnr(struct l2cap_chan *chan)
+static void l2cap_send_i_or_rr_or_rnr(struct l2cap_chan *chan)
 {
-       u32 control = 0;
+       struct l2cap_ctrl control;
 
-       chan->frames_sent = 0;
+       BT_DBG("chan %p", chan);
 
-       control |= __set_reqseq(chan, chan->buffer_seq);
+       memset(&control, 0, sizeof(control));
+       control.sframe = 1;
+       control.final = 1;
+       control.reqseq = chan->buffer_seq;
+       set_bit(CONN_SEND_FBIT, &chan->conn_state);
 
        if (test_bit(CONN_LOCAL_BUSY, &chan->conn_state)) {
-               control |= __set_ctrl_super(chan, L2CAP_SUPER_RNR);
-               l2cap_send_sframe(chan, control);
-               set_bit(CONN_RNR_SENT, &chan->conn_state);
+               control.super = L2CAP_SUPER_RNR;
+               l2cap_send_sframe(chan, &control);
        }
 
-       if (test_bit(CONN_REMOTE_BUSY, &chan->conn_state))
-               l2cap_retransmit_frames(chan);
+       if (test_and_clear_bit(CONN_REMOTE_BUSY, &chan->conn_state) &&
+           chan->unacked_frames > 0)
+               __set_retrans_timer(chan);
 
+       /* Send pending iframes */
        l2cap_ertm_send(chan);
 
        if (!test_bit(CONN_LOCAL_BUSY, &chan->conn_state) &&
-                       chan->frames_sent == 0) {
-               control |= __set_ctrl_super(chan, L2CAP_SUPER_RR);
-               l2cap_send_sframe(chan, control);
+           test_bit(CONN_SEND_FBIT, &chan->conn_state)) {
+               /* F-bit wasn't sent in an s-frame or i-frame yet, so
+                * send it now.
+                */
+               control.super = L2CAP_SUPER_RR;
+               l2cap_send_sframe(chan, &control);
        }
 }
 
-static int l2cap_add_to_srej_queue(struct l2cap_chan *chan, struct sk_buff *skb, u16 tx_seq, u8 sar)
-{
-       struct sk_buff *next_skb;
-       int tx_seq_offset, next_tx_seq_offset;
-
-       bt_cb(skb)->control.txseq = tx_seq;
-       bt_cb(skb)->control.sar = sar;
-
-       next_skb = skb_peek(&chan->srej_q);
-
-       tx_seq_offset = __seq_offset(chan, tx_seq, chan->buffer_seq);
-
-       while (next_skb) {
-               if (bt_cb(next_skb)->control.txseq == tx_seq)
-                       return -EINVAL;
-
-               next_tx_seq_offset = __seq_offset(chan,
-                       bt_cb(next_skb)->control.txseq, chan->buffer_seq);
-
-               if (next_tx_seq_offset > tx_seq_offset) {
-                       __skb_queue_before(&chan->srej_q, next_skb, skb);
-                       return 0;
-               }
-
-               if (skb_queue_is_last(&chan->srej_q, next_skb))
-                       next_skb = NULL;
-               else
-                       next_skb = skb_queue_next(&chan->srej_q, next_skb);
-       }
-
-       __skb_queue_tail(&chan->srej_q, skb);
-
-       return 0;
-}
-
 static void append_skb_frag(struct sk_buff *skb,
                        struct sk_buff *new_frag, struct sk_buff **last_frag)
 {
@@ -4045,11 +4460,12 @@ static void append_skb_frag(struct sk_buff *skb,
        skb->truesize += new_frag->truesize;
 }
 
-static int l2cap_reassemble_sdu(struct l2cap_chan *chan, struct sk_buff *skb, u32 control)
+static int l2cap_reassemble_sdu(struct l2cap_chan *chan, struct sk_buff *skb,
+                               struct l2cap_ctrl *control)
 {
        int err = -EINVAL;
 
-       switch (__get_ctrl_sar(chan, control)) {
+       switch (control->sar) {
        case L2CAP_SAR_UNSEGMENTED:
                if (chan->sdu)
                        break;
@@ -4126,448 +4542,609 @@ static int l2cap_reassemble_sdu(struct l2cap_chan *chan, struct sk_buff *skb, u3
        return err;
 }
 
-static void l2cap_ertm_enter_local_busy(struct l2cap_chan *chan)
+void l2cap_chan_busy(struct l2cap_chan *chan, int busy)
 {
-       BT_DBG("chan %p, Enter local busy", chan);
+       u8 event;
 
-       set_bit(CONN_LOCAL_BUSY, &chan->conn_state);
-       l2cap_seq_list_clear(&chan->srej_list);
+       if (chan->mode != L2CAP_MODE_ERTM)
+               return;
 
-       __set_ack_timer(chan);
+       event = busy ? L2CAP_EV_LOCAL_BUSY_DETECTED : L2CAP_EV_LOCAL_BUSY_CLEAR;
+       l2cap_tx(chan, NULL, NULL, event);
 }
 
-static void l2cap_ertm_exit_local_busy(struct l2cap_chan *chan)
+static int l2cap_rx_queued_iframes(struct l2cap_chan *chan)
 {
-       u32 control;
-
-       if (!test_bit(CONN_RNR_SENT, &chan->conn_state))
-               goto done;
+       int err = 0;
+       /* Pass sequential frames to l2cap_reassemble_sdu()
+        * until a gap is encountered.
+        */
 
-       control = __set_reqseq(chan, chan->buffer_seq);
-       control |= __set_ctrl_poll(chan);
-       control |= __set_ctrl_super(chan, L2CAP_SUPER_RR);
-       l2cap_send_sframe(chan, control);
-       chan->retry_count = 1;
+       BT_DBG("chan %p", chan);
 
-       __clear_retrans_timer(chan);
-       __set_monitor_timer(chan);
+       while (!test_bit(CONN_LOCAL_BUSY, &chan->conn_state)) {
+               struct sk_buff *skb;
+               BT_DBG("Searching for skb with txseq %d (queue len %d)",
+                      chan->buffer_seq, skb_queue_len(&chan->srej_q));
 
-       set_bit(CONN_WAIT_F, &chan->conn_state);
+               skb = l2cap_ertm_seq_in_queue(&chan->srej_q, chan->buffer_seq);
 
-done:
-       clear_bit(CONN_LOCAL_BUSY, &chan->conn_state);
-       clear_bit(CONN_RNR_SENT, &chan->conn_state);
+               if (!skb)
+                       break;
 
-       BT_DBG("chan %p, Exit local busy", chan);
-}
+               skb_unlink(skb, &chan->srej_q);
+               chan->buffer_seq = __next_seq(chan, chan->buffer_seq);
+               err = l2cap_reassemble_sdu(chan, skb, &bt_cb(skb)->control);
+               if (err)
+                       break;
+       }
 
-void l2cap_chan_busy(struct l2cap_chan *chan, int busy)
-{
-       if (chan->mode == L2CAP_MODE_ERTM) {
-               if (busy)
-                       l2cap_ertm_enter_local_busy(chan);
-               else
-                       l2cap_ertm_exit_local_busy(chan);
+       if (skb_queue_empty(&chan->srej_q)) {
+               chan->rx_state = L2CAP_RX_STATE_RECV;
+               l2cap_send_ack(chan);
        }
+
+       return err;
 }
 
-static void l2cap_check_srej_gap(struct l2cap_chan *chan, u16 tx_seq)
+static void l2cap_handle_srej(struct l2cap_chan *chan,
+                             struct l2cap_ctrl *control)
 {
        struct sk_buff *skb;
-       u32 control;
 
-       while ((skb = skb_peek(&chan->srej_q)) &&
-                       !test_bit(CONN_LOCAL_BUSY, &chan->conn_state)) {
-               int err;
+       BT_DBG("chan %p, control %p", chan, control);
 
-               if (bt_cb(skb)->control.txseq != tx_seq)
-                       break;
+       if (control->reqseq == chan->next_tx_seq) {
+               BT_DBG("Invalid reqseq %d, disconnecting", control->reqseq);
+               l2cap_send_disconn_req(chan->conn, chan, ECONNRESET);
+               return;
+       }
 
-               skb = skb_dequeue(&chan->srej_q);
-               control = __set_ctrl_sar(chan, bt_cb(skb)->control.sar);
-               err = l2cap_reassemble_sdu(chan, skb, control);
+       skb = l2cap_ertm_seq_in_queue(&chan->tx_q, control->reqseq);
 
-               if (err < 0) {
-                       l2cap_send_disconn_req(chan->conn, chan, ECONNRESET);
-                       break;
-               }
+       if (skb == NULL) {
+               BT_DBG("Seq %d not available for retransmission",
+                      control->reqseq);
+               return;
+       }
 
-               chan->buffer_seq_srej = __next_seq(chan, chan->buffer_seq_srej);
-               tx_seq = __next_seq(chan, tx_seq);
+       if (chan->max_tx != 0 && bt_cb(skb)->control.retries >= chan->max_tx) {
+               BT_DBG("Retry limit exceeded (%d)", chan->max_tx);
+               l2cap_send_disconn_req(chan->conn, chan, ECONNRESET);
+               return;
        }
-}
 
-static void l2cap_resend_srejframe(struct l2cap_chan *chan, u16 tx_seq)
-{
-       struct srej_list *l, *tmp;
-       u32 control;
+       clear_bit(CONN_REMOTE_BUSY, &chan->conn_state);
 
-       list_for_each_entry_safe(l, tmp, &chan->srej_l, list) {
-               if (l->tx_seq == tx_seq) {
-                       list_del(&l->list);
-                       kfree(l);
-                       return;
+       if (control->poll) {
+               l2cap_pass_to_tx(chan, control);
+
+               set_bit(CONN_SEND_FBIT, &chan->conn_state);
+               l2cap_retransmit(chan, control);
+               l2cap_ertm_send(chan);
+
+               if (chan->tx_state == L2CAP_TX_STATE_WAIT_F) {
+                       set_bit(CONN_SREJ_ACT, &chan->conn_state);
+                       chan->srej_save_reqseq = control->reqseq;
+               }
+       } else {
+               l2cap_pass_to_tx_fbit(chan, control);
+
+               if (control->final) {
+                       if (chan->srej_save_reqseq != control->reqseq ||
+                           !test_and_clear_bit(CONN_SREJ_ACT,
+                                               &chan->conn_state))
+                               l2cap_retransmit(chan, control);
+               } else {
+                       l2cap_retransmit(chan, control);
+                       if (chan->tx_state == L2CAP_TX_STATE_WAIT_F) {
+                               set_bit(CONN_SREJ_ACT, &chan->conn_state);
+                               chan->srej_save_reqseq = control->reqseq;
+                       }
                }
-               control = __set_ctrl_super(chan, L2CAP_SUPER_SREJ);
-               control |= __set_reqseq(chan, l->tx_seq);
-               l2cap_send_sframe(chan, control);
-               list_del(&l->list);
-               list_add_tail(&l->list, &chan->srej_l);
        }
 }
 
-static int l2cap_send_srejframe(struct l2cap_chan *chan, u16 tx_seq)
+static void l2cap_handle_rej(struct l2cap_chan *chan,
+                            struct l2cap_ctrl *control)
 {
-       struct srej_list *new;
-       u32 control;
-
-       while (tx_seq != chan->expected_tx_seq) {
-               control = __set_ctrl_super(chan, L2CAP_SUPER_SREJ);
-               control |= __set_reqseq(chan, chan->expected_tx_seq);
-               l2cap_seq_list_append(&chan->srej_list, chan->expected_tx_seq);
-               l2cap_send_sframe(chan, control);
+       struct sk_buff *skb;
 
-               new = kzalloc(sizeof(struct srej_list), GFP_ATOMIC);
-               if (!new)
-                       return -ENOMEM;
+       BT_DBG("chan %p, control %p", chan, control);
 
-               new->tx_seq = chan->expected_tx_seq;
+       if (control->reqseq == chan->next_tx_seq) {
+               BT_DBG("Invalid reqseq %d, disconnecting", control->reqseq);
+               l2cap_send_disconn_req(chan->conn, chan, ECONNRESET);
+               return;
+       }
 
-               chan->expected_tx_seq = __next_seq(chan, chan->expected_tx_seq);
+       skb = l2cap_ertm_seq_in_queue(&chan->tx_q, control->reqseq);
 
-               list_add_tail(&new->list, &chan->srej_l);
+       if (chan->max_tx && skb &&
+           bt_cb(skb)->control.retries >= chan->max_tx) {
+               BT_DBG("Retry limit exceeded (%d)", chan->max_tx);
+               l2cap_send_disconn_req(chan->conn, chan, ECONNRESET);
+               return;
        }
 
-       chan->expected_tx_seq = __next_seq(chan, chan->expected_tx_seq);
+       clear_bit(CONN_REMOTE_BUSY, &chan->conn_state);
 
-       return 0;
+       l2cap_pass_to_tx(chan, control);
+
+       if (control->final) {
+               if (!test_and_clear_bit(CONN_REJ_ACT, &chan->conn_state))
+                       l2cap_retransmit_all(chan, control);
+       } else {
+               l2cap_retransmit_all(chan, control);
+               l2cap_ertm_send(chan);
+               if (chan->tx_state == L2CAP_TX_STATE_WAIT_F)
+                       set_bit(CONN_REJ_ACT, &chan->conn_state);
+       }
 }
 
-static inline int l2cap_data_channel_iframe(struct l2cap_chan *chan, u32 rx_control, struct sk_buff *skb)
+static u8 l2cap_classify_txseq(struct l2cap_chan *chan, u16 txseq)
 {
-       u16 tx_seq = __get_txseq(chan, rx_control);
-       u16 req_seq = __get_reqseq(chan, rx_control);
-       u8 sar = __get_ctrl_sar(chan, rx_control);
-       int tx_seq_offset, expected_tx_seq_offset;
-       int num_to_ack = (chan->tx_win/6) + 1;
-       int err = 0;
+       BT_DBG("chan %p, txseq %d", chan, txseq);
 
-       BT_DBG("chan %p len %d tx_seq %d rx_control 0x%8.8x", chan, skb->len,
-                                                       tx_seq, rx_control);
+       BT_DBG("last_acked_seq %d, expected_tx_seq %d", chan->last_acked_seq,
+              chan->expected_tx_seq);
 
-       if (__is_ctrl_final(chan, rx_control) &&
-                       test_bit(CONN_WAIT_F, &chan->conn_state)) {
-               __clear_monitor_timer(chan);
-               if (chan->unacked_frames > 0)
-                       __set_retrans_timer(chan);
-               clear_bit(CONN_WAIT_F, &chan->conn_state);
-       }
+       if (chan->rx_state == L2CAP_RX_STATE_SREJ_SENT) {
+               if (__seq_offset(chan, txseq, chan->last_acked_seq) >=
+                                                               chan->tx_win) {
+                       /* See notes below regarding "double poll" and
+                        * invalid packets.
+                        */
+                       if (chan->tx_win <= ((chan->tx_win_max + 1) >> 1)) {
+                               BT_DBG("Invalid/Ignore - after SREJ");
+                               return L2CAP_TXSEQ_INVALID_IGNORE;
+                       } else {
+                               BT_DBG("Invalid - in window after SREJ sent");
+                               return L2CAP_TXSEQ_INVALID;
+                       }
+               }
 
-       chan->expected_ack_seq = req_seq;
-       l2cap_drop_acked_frames(chan);
+               if (chan->srej_list.head == txseq) {
+                       BT_DBG("Expected SREJ");
+                       return L2CAP_TXSEQ_EXPECTED_SREJ;
+               }
 
-       tx_seq_offset = __seq_offset(chan, tx_seq, chan->buffer_seq);
+               if (l2cap_ertm_seq_in_queue(&chan->srej_q, txseq)) {
+                       BT_DBG("Duplicate SREJ - txseq already stored");
+                       return L2CAP_TXSEQ_DUPLICATE_SREJ;
+               }
 
-       /* invalid tx_seq */
-       if (tx_seq_offset >= chan->tx_win) {
-               l2cap_send_disconn_req(chan->conn, chan, ECONNRESET);
-               goto drop;
+               if (l2cap_seq_list_contains(&chan->srej_list, txseq)) {
+                       BT_DBG("Unexpected SREJ - not requested");
+                       return L2CAP_TXSEQ_UNEXPECTED_SREJ;
+               }
        }
 
-       if (test_bit(CONN_LOCAL_BUSY, &chan->conn_state)) {
-               if (!test_bit(CONN_RNR_SENT, &chan->conn_state))
-                       l2cap_send_ack(chan);
-               goto drop;
+       if (chan->expected_tx_seq == txseq) {
+               if (__seq_offset(chan, txseq, chan->last_acked_seq) >=
+                   chan->tx_win) {
+                       BT_DBG("Invalid - txseq outside tx window");
+                       return L2CAP_TXSEQ_INVALID;
+               } else {
+                       BT_DBG("Expected");
+                       return L2CAP_TXSEQ_EXPECTED;
+               }
        }
 
-       if (tx_seq == chan->expected_tx_seq)
-               goto expected;
+       if (__seq_offset(chan, txseq, chan->last_acked_seq) <
+               __seq_offset(chan, chan->expected_tx_seq,
+                            chan->last_acked_seq)){
+               BT_DBG("Duplicate - expected_tx_seq later than txseq");
+               return L2CAP_TXSEQ_DUPLICATE;
+       }
+
+       if (__seq_offset(chan, txseq, chan->last_acked_seq) >= chan->tx_win) {
+               /* A source of invalid packets is a "double poll" condition,
+                * where delays cause us to send multiple poll packets.  If
+                * the remote stack receives and processes both polls,
+                * sequence numbers can wrap around in such a way that a
+                * resent frame has a sequence number that looks like new data
+                * with a sequence gap.  This would trigger an erroneous SREJ
+                * request.
+                *
+                * Fortunately, this is impossible with a tx window that's
+                * less than half of the maximum sequence number, which allows
+                * invalid frames to be safely ignored.
+                *
+                * With tx window sizes greater than half of the tx window
+                * maximum, the frame is invalid and cannot be ignored.  This
+                * causes a disconnect.
+                */
 
-       if (test_bit(CONN_SREJ_SENT, &chan->conn_state)) {
-               struct srej_list *first;
+               if (chan->tx_win <= ((chan->tx_win_max + 1) >> 1)) {
+                       BT_DBG("Invalid/Ignore - txseq outside tx window");
+                       return L2CAP_TXSEQ_INVALID_IGNORE;
+               } else {
+                       BT_DBG("Invalid - txseq outside tx window");
+                       return L2CAP_TXSEQ_INVALID;
+               }
+       } else {
+               BT_DBG("Unexpected - txseq indicates missing frames");
+               return L2CAP_TXSEQ_UNEXPECTED;
+       }
+}
+
+static int l2cap_rx_state_recv(struct l2cap_chan *chan,
+                              struct l2cap_ctrl *control,
+                              struct sk_buff *skb, u8 event)
+{
+       int err = 0;
+       bool skb_in_use = 0;
 
-               first = list_first_entry(&chan->srej_l,
-                               struct srej_list, list);
-               if (tx_seq == first->tx_seq) {
-                       l2cap_add_to_srej_queue(chan, skb, tx_seq, sar);
-                       l2cap_check_srej_gap(chan, tx_seq);
+       BT_DBG("chan %p, control %p, skb %p, event %d", chan, control, skb,
+              event);
 
-                       list_del(&first->list);
-                       kfree(first);
+       switch (event) {
+       case L2CAP_EV_RECV_IFRAME:
+               switch (l2cap_classify_txseq(chan, control->txseq)) {
+               case L2CAP_TXSEQ_EXPECTED:
+                       l2cap_pass_to_tx(chan, control);
 
-                       if (list_empty(&chan->srej_l)) {
-                               chan->buffer_seq = chan->buffer_seq_srej;
-                               clear_bit(CONN_SREJ_SENT, &chan->conn_state);
-                               l2cap_send_ack(chan);
-                               BT_DBG("chan %p, Exit SREJ_SENT", chan);
+                       if (test_bit(CONN_LOCAL_BUSY, &chan->conn_state)) {
+                               BT_DBG("Busy, discarding expected seq %d",
+                                      control->txseq);
+                               break;
                        }
-               } else {
-                       struct srej_list *l;
 
-                       /* duplicated tx_seq */
-                       if (l2cap_add_to_srej_queue(chan, skb, tx_seq, sar) < 0)
-                               goto drop;
+                       chan->expected_tx_seq = __next_seq(chan,
+                                                          control->txseq);
 
-                       list_for_each_entry(l, &chan->srej_l, list) {
-                               if (l->tx_seq == tx_seq) {
-                                       l2cap_resend_srejframe(chan, tx_seq);
-                                       return 0;
+                       chan->buffer_seq = chan->expected_tx_seq;
+                       skb_in_use = 1;
+
+                       err = l2cap_reassemble_sdu(chan, skb, control);
+                       if (err)
+                               break;
+
+                       if (control->final) {
+                               if (!test_and_clear_bit(CONN_REJ_ACT,
+                                                       &chan->conn_state)) {
+                                       control->final = 0;
+                                       l2cap_retransmit_all(chan, control);
+                                       l2cap_ertm_send(chan);
                                }
                        }
 
-                       err = l2cap_send_srejframe(chan, tx_seq);
-                       if (err < 0) {
-                               l2cap_send_disconn_req(chan->conn, chan, -err);
-                               return err;
+                       if (!test_bit(CONN_LOCAL_BUSY, &chan->conn_state))
+                               l2cap_send_ack(chan);
+                       break;
+               case L2CAP_TXSEQ_UNEXPECTED:
+                       l2cap_pass_to_tx(chan, control);
+
+                       /* Can't issue SREJ frames in the local busy state.
+                        * Drop this frame, it will be seen as missing
+                        * when local busy is exited.
+                        */
+                       if (test_bit(CONN_LOCAL_BUSY, &chan->conn_state)) {
+                               BT_DBG("Busy, discarding unexpected seq %d",
+                                      control->txseq);
+                               break;
                        }
-               }
-       } else {
-               expected_tx_seq_offset = __seq_offset(chan,
-                               chan->expected_tx_seq, chan->buffer_seq);
 
-               /* duplicated tx_seq */
-               if (tx_seq_offset < expected_tx_seq_offset)
-                       goto drop;
-
-               set_bit(CONN_SREJ_SENT, &chan->conn_state);
+                       /* There was a gap in the sequence, so an SREJ
+                        * must be sent for each missing frame.  The
+                        * current frame is stored for later use.
+                        */
+                       skb_queue_tail(&chan->srej_q, skb);
+                       skb_in_use = 1;
+                       BT_DBG("Queued %p (queue len %d)", skb,
+                              skb_queue_len(&chan->srej_q));
 
-               BT_DBG("chan %p, Enter SREJ", chan);
+                       clear_bit(CONN_SREJ_ACT, &chan->conn_state);
+                       l2cap_seq_list_clear(&chan->srej_list);
+                       l2cap_send_srej(chan, control->txseq);
 
-               INIT_LIST_HEAD(&chan->srej_l);
-               chan->buffer_seq_srej = chan->buffer_seq;
+                       chan->rx_state = L2CAP_RX_STATE_SREJ_SENT;
+                       break;
+               case L2CAP_TXSEQ_DUPLICATE:
+                       l2cap_pass_to_tx(chan, control);
+                       break;
+               case L2CAP_TXSEQ_INVALID_IGNORE:
+                       break;
+               case L2CAP_TXSEQ_INVALID:
+               default:
+                       l2cap_send_disconn_req(chan->conn, chan,
+                                              ECONNRESET);
+                       break;
+               }
+               break;
+       case L2CAP_EV_RECV_RR:
+               l2cap_pass_to_tx(chan, control);
+               if (control->final) {
+                       clear_bit(CONN_REMOTE_BUSY, &chan->conn_state);
 
-               __skb_queue_head_init(&chan->srej_q);
-               l2cap_add_to_srej_queue(chan, skb, tx_seq, sar);
+                       if (!test_and_clear_bit(CONN_REJ_ACT,
+                                               &chan->conn_state)) {
+                               control->final = 0;
+                               l2cap_retransmit_all(chan, control);
+                       }
 
-               /* Set P-bit only if there are some I-frames to ack. */
-               if (__clear_ack_timer(chan))
-                       set_bit(CONN_SEND_PBIT, &chan->conn_state);
+                       l2cap_ertm_send(chan);
+               } else if (control->poll) {
+                       l2cap_send_i_or_rr_or_rnr(chan);
+               } else {
+                       if (test_and_clear_bit(CONN_REMOTE_BUSY,
+                                              &chan->conn_state) &&
+                           chan->unacked_frames)
+                               __set_retrans_timer(chan);
 
-               err = l2cap_send_srejframe(chan, tx_seq);
-               if (err < 0) {
-                       l2cap_send_disconn_req(chan->conn, chan, -err);
-                       return err;
+                       l2cap_ertm_send(chan);
                }
+               break;
+       case L2CAP_EV_RECV_RNR:
+               set_bit(CONN_REMOTE_BUSY, &chan->conn_state);
+               l2cap_pass_to_tx(chan, control);
+               if (control && control->poll) {
+                       set_bit(CONN_SEND_FBIT, &chan->conn_state);
+                       l2cap_send_rr_or_rnr(chan, 0);
+               }
+               __clear_retrans_timer(chan);
+               l2cap_seq_list_clear(&chan->retrans_list);
+               break;
+       case L2CAP_EV_RECV_REJ:
+               l2cap_handle_rej(chan, control);
+               break;
+       case L2CAP_EV_RECV_SREJ:
+               l2cap_handle_srej(chan, control);
+               break;
+       default:
+               break;
        }
-       return 0;
-
-expected:
-       chan->expected_tx_seq = __next_seq(chan, chan->expected_tx_seq);
-
-       if (test_bit(CONN_SREJ_SENT, &chan->conn_state)) {
-               bt_cb(skb)->control.txseq = tx_seq;
-               bt_cb(skb)->control.sar = sar;
-               __skb_queue_tail(&chan->srej_q, skb);
-               return 0;
-       }
-
-       err = l2cap_reassemble_sdu(chan, skb, rx_control);
-       chan->buffer_seq = __next_seq(chan, chan->buffer_seq);
 
-       if (err < 0) {
-               l2cap_send_disconn_req(chan->conn, chan, ECONNRESET);
-               return err;
+       if (skb && !skb_in_use) {
+               BT_DBG("Freeing %p", skb);
+               kfree_skb(skb);
        }
 
-       if (__is_ctrl_final(chan, rx_control)) {
-               if (!test_and_clear_bit(CONN_REJ_ACT, &chan->conn_state))
-                       l2cap_retransmit_frames(chan);
-       }
+       return err;
+}
 
+static int l2cap_rx_state_srej_sent(struct l2cap_chan *chan,
+                                   struct l2cap_ctrl *control,
+                                   struct sk_buff *skb, u8 event)
+{
+       int err = 0;
+       u16 txseq = control->txseq;
+       bool skb_in_use = 0;
+
+       BT_DBG("chan %p, control %p, skb %p, event %d", chan, control, skb,
+              event);
+
+       switch (event) {
+       case L2CAP_EV_RECV_IFRAME:
+               switch (l2cap_classify_txseq(chan, txseq)) {
+               case L2CAP_TXSEQ_EXPECTED:
+                       /* Keep frame for reassembly later */
+                       l2cap_pass_to_tx(chan, control);
+                       skb_queue_tail(&chan->srej_q, skb);
+                       skb_in_use = 1;
+                       BT_DBG("Queued %p (queue len %d)", skb,
+                              skb_queue_len(&chan->srej_q));
+
+                       chan->expected_tx_seq = __next_seq(chan, txseq);
+                       break;
+               case L2CAP_TXSEQ_EXPECTED_SREJ:
+                       l2cap_seq_list_pop(&chan->srej_list);
 
-       chan->num_acked = (chan->num_acked + 1) % num_to_ack;
-       if (chan->num_acked == num_to_ack - 1)
-               l2cap_send_ack(chan);
-       else
-               __set_ack_timer(chan);
+                       l2cap_pass_to_tx(chan, control);
+                       skb_queue_tail(&chan->srej_q, skb);
+                       skb_in_use = 1;
+                       BT_DBG("Queued %p (queue len %d)", skb,
+                              skb_queue_len(&chan->srej_q));
 
-       return 0;
+                       err = l2cap_rx_queued_iframes(chan);
+                       if (err)
+                               break;
 
-drop:
-       kfree_skb(skb);
-       return 0;
-}
+                       break;
+               case L2CAP_TXSEQ_UNEXPECTED:
+                       /* Got a frame that can't be reassembled yet.
+                        * Save it for later, and send SREJs to cover
+                        * the missing frames.
+                        */
+                       skb_queue_tail(&chan->srej_q, skb);
+                       skb_in_use = 1;
+                       BT_DBG("Queued %p (queue len %d)", skb,
+                              skb_queue_len(&chan->srej_q));
+
+                       l2cap_pass_to_tx(chan, control);
+                       l2cap_send_srej(chan, control->txseq);
+                       break;
+               case L2CAP_TXSEQ_UNEXPECTED_SREJ:
+                       /* This frame was requested with an SREJ, but
+                        * some expected retransmitted frames are
+                        * missing.  Request retransmission of missing
+                        * SREJ'd frames.
+                        */
+                       skb_queue_tail(&chan->srej_q, skb);
+                       skb_in_use = 1;
+                       BT_DBG("Queued %p (queue len %d)", skb,
+                              skb_queue_len(&chan->srej_q));
+
+                       l2cap_pass_to_tx(chan, control);
+                       l2cap_send_srej_list(chan, control->txseq);
+                       break;
+               case L2CAP_TXSEQ_DUPLICATE_SREJ:
+                       /* We've already queued this frame.  Drop this copy. */
+                       l2cap_pass_to_tx(chan, control);
+                       break;
+               case L2CAP_TXSEQ_DUPLICATE:
+                       /* Expecting a later sequence number, so this frame
+                        * was already received.  Ignore it completely.
+                        */
+                       break;
+               case L2CAP_TXSEQ_INVALID_IGNORE:
+                       break;
+               case L2CAP_TXSEQ_INVALID:
+               default:
+                       l2cap_send_disconn_req(chan->conn, chan,
+                                              ECONNRESET);
+                       break;
+               }
+               break;
+       case L2CAP_EV_RECV_RR:
+               l2cap_pass_to_tx(chan, control);
+               if (control->final) {
+                       clear_bit(CONN_REMOTE_BUSY, &chan->conn_state);
 
-static inline void l2cap_data_channel_rrframe(struct l2cap_chan *chan, u32 rx_control)
-{
-       BT_DBG("chan %p, req_seq %d ctrl 0x%8.8x", chan,
-                               __get_reqseq(chan, rx_control), rx_control);
+                       if (!test_and_clear_bit(CONN_REJ_ACT,
+                                               &chan->conn_state)) {
+                               control->final = 0;
+                               l2cap_retransmit_all(chan, control);
+                       }
 
-       chan->expected_ack_seq = __get_reqseq(chan, rx_control);
-       l2cap_drop_acked_frames(chan);
+                       l2cap_ertm_send(chan);
+               } else if (control->poll) {
+                       if (test_and_clear_bit(CONN_REMOTE_BUSY,
+                                              &chan->conn_state) &&
+                           chan->unacked_frames) {
+                               __set_retrans_timer(chan);
+                       }
 
-       if (__is_ctrl_poll(chan, rx_control)) {
-               set_bit(CONN_SEND_FBIT, &chan->conn_state);
-               if (test_bit(CONN_SREJ_SENT, &chan->conn_state)) {
-                       if (test_bit(CONN_REMOTE_BUSY, &chan->conn_state) &&
-                                       (chan->unacked_frames > 0))
+                       set_bit(CONN_SEND_FBIT, &chan->conn_state);
+                       l2cap_send_srej_tail(chan);
+               } else {
+                       if (test_and_clear_bit(CONN_REMOTE_BUSY,
+                                              &chan->conn_state) &&
+                           chan->unacked_frames)
                                __set_retrans_timer(chan);
 
-                       clear_bit(CONN_REMOTE_BUSY, &chan->conn_state);
-                       l2cap_send_srejtail(chan);
+                       l2cap_send_ack(chan);
+               }
+               break;
+       case L2CAP_EV_RECV_RNR:
+               set_bit(CONN_REMOTE_BUSY, &chan->conn_state);
+               l2cap_pass_to_tx(chan, control);
+               if (control->poll) {
+                       l2cap_send_srej_tail(chan);
                } else {
-                       l2cap_send_i_or_rr_or_rnr(chan);
+                       struct l2cap_ctrl rr_control;
+                       memset(&rr_control, 0, sizeof(rr_control));
+                       rr_control.sframe = 1;
+                       rr_control.super = L2CAP_SUPER_RR;
+                       rr_control.reqseq = chan->buffer_seq;
+                       l2cap_send_sframe(chan, &rr_control);
                }
 
-       } else if (__is_ctrl_final(chan, rx_control)) {
-               clear_bit(CONN_REMOTE_BUSY, &chan->conn_state);
-
-               if (!test_and_clear_bit(CONN_REJ_ACT, &chan->conn_state))
-                       l2cap_retransmit_frames(chan);
-
-       } else {
-               if (test_bit(CONN_REMOTE_BUSY, &chan->conn_state) &&
-                               (chan->unacked_frames > 0))
-                       __set_retrans_timer(chan);
+               break;
+       case L2CAP_EV_RECV_REJ:
+               l2cap_handle_rej(chan, control);
+               break;
+       case L2CAP_EV_RECV_SREJ:
+               l2cap_handle_srej(chan, control);
+               break;
+       }
 
-               clear_bit(CONN_REMOTE_BUSY, &chan->conn_state);
-               if (test_bit(CONN_SREJ_SENT, &chan->conn_state))
-                       l2cap_send_ack(chan);
-               else
-                       l2cap_ertm_send(chan);
+       if (skb && !skb_in_use) {
+               BT_DBG("Freeing %p", skb);
+               kfree_skb(skb);
        }
+
+       return err;
 }
 
-static inline void l2cap_data_channel_rejframe(struct l2cap_chan *chan, u32 rx_control)
+static bool __valid_reqseq(struct l2cap_chan *chan, u16 reqseq)
 {
-       u16 tx_seq = __get_reqseq(chan, rx_control);
-
-       BT_DBG("chan %p, req_seq %d ctrl 0x%8.8x", chan, tx_seq, rx_control);
-
-       clear_bit(CONN_REMOTE_BUSY, &chan->conn_state);
-
-       chan->expected_ack_seq = tx_seq;
-       l2cap_drop_acked_frames(chan);
-
-       if (__is_ctrl_final(chan, rx_control)) {
-               if (!test_and_clear_bit(CONN_REJ_ACT, &chan->conn_state))
-                       l2cap_retransmit_frames(chan);
-       } else {
-               l2cap_retransmit_frames(chan);
+       /* Make sure reqseq is for a packet that has been sent but not acked */
+       u16 unacked;
 
-               if (test_bit(CONN_WAIT_F, &chan->conn_state))
-                       set_bit(CONN_REJ_ACT, &chan->conn_state);
-       }
+       unacked = __seq_offset(chan, chan->next_tx_seq, chan->expected_ack_seq);
+       return __seq_offset(chan, chan->next_tx_seq, reqseq) <= unacked;
 }
-static inline void l2cap_data_channel_srejframe(struct l2cap_chan *chan, u32 rx_control)
-{
-       u16 tx_seq = __get_reqseq(chan, rx_control);
-
-       BT_DBG("chan %p, req_seq %d ctrl 0x%8.8x", chan, tx_seq, rx_control);
 
-       clear_bit(CONN_REMOTE_BUSY, &chan->conn_state);
-
-       if (__is_ctrl_poll(chan, rx_control)) {
-               chan->expected_ack_seq = tx_seq;
-               l2cap_drop_acked_frames(chan);
-
-               set_bit(CONN_SEND_FBIT, &chan->conn_state);
-               l2cap_retransmit_one_frame(chan, tx_seq);
+static int l2cap_rx(struct l2cap_chan *chan, struct l2cap_ctrl *control,
+                   struct sk_buff *skb, u8 event)
+{
+       int err = 0;
 
-               l2cap_ertm_send(chan);
+       BT_DBG("chan %p, control %p, skb %p, event %d, state %d", chan,
+              control, skb, event, chan->rx_state);
 
-               if (test_bit(CONN_WAIT_F, &chan->conn_state)) {
-                       chan->srej_save_reqseq = tx_seq;
-                       set_bit(CONN_SREJ_ACT, &chan->conn_state);
+       if (__valid_reqseq(chan, control->reqseq)) {
+               switch (chan->rx_state) {
+               case L2CAP_RX_STATE_RECV:
+                       err = l2cap_rx_state_recv(chan, control, skb, event);
+                       break;
+               case L2CAP_RX_STATE_SREJ_SENT:
+                       err = l2cap_rx_state_srej_sent(chan, control, skb,
+                                                      event);
+                       break;
+               default:
+                       /* shut it down */
+                       break;
                }
-       } else if (__is_ctrl_final(chan, rx_control)) {
-               if (test_bit(CONN_SREJ_ACT, &chan->conn_state) &&
-                               chan->srej_save_reqseq == tx_seq)
-                       clear_bit(CONN_SREJ_ACT, &chan->conn_state);
-               else
-                       l2cap_retransmit_one_frame(chan, tx_seq);
        } else {
-               l2cap_retransmit_one_frame(chan, tx_seq);
-               if (test_bit(CONN_WAIT_F, &chan->conn_state)) {
-                       chan->srej_save_reqseq = tx_seq;
-                       set_bit(CONN_SREJ_ACT, &chan->conn_state);
-               }
+               BT_DBG("Invalid reqseq %d (next_tx_seq %d, expected_ack_seq %d",
+                      control->reqseq, chan->next_tx_seq,
+                      chan->expected_ack_seq);
+               l2cap_send_disconn_req(chan->conn, chan, ECONNRESET);
        }
+
+       return err;
 }
 
-static inline void l2cap_data_channel_rnrframe(struct l2cap_chan *chan, u32 rx_control)
+static int l2cap_stream_rx(struct l2cap_chan *chan, struct l2cap_ctrl *control,
+                          struct sk_buff *skb)
 {
-       u16 tx_seq = __get_reqseq(chan, rx_control);
+       int err = 0;
 
-       BT_DBG("chan %p, req_seq %d ctrl 0x%8.8x", chan, tx_seq, rx_control);
+       BT_DBG("chan %p, control %p, skb %p, state %d", chan, control, skb,
+              chan->rx_state);
 
-       set_bit(CONN_REMOTE_BUSY, &chan->conn_state);
-       chan->expected_ack_seq = tx_seq;
-       l2cap_drop_acked_frames(chan);
+       if (l2cap_classify_txseq(chan, control->txseq) ==
+           L2CAP_TXSEQ_EXPECTED) {
+               l2cap_pass_to_tx(chan, control);
 
-       if (__is_ctrl_poll(chan, rx_control))
-               set_bit(CONN_SEND_FBIT, &chan->conn_state);
+               BT_DBG("buffer_seq %d->%d", chan->buffer_seq,
+                      __next_seq(chan, chan->buffer_seq));
 
-       if (!test_bit(CONN_SREJ_SENT, &chan->conn_state)) {
-               __clear_retrans_timer(chan);
-               if (__is_ctrl_poll(chan, rx_control))
-                       l2cap_send_rr_or_rnr(chan, L2CAP_CTRL_FINAL);
-               return;
-       }
+               chan->buffer_seq = __next_seq(chan, chan->buffer_seq);
 
-       if (__is_ctrl_poll(chan, rx_control)) {
-               l2cap_send_srejtail(chan);
+               l2cap_reassemble_sdu(chan, skb, control);
        } else {
-               rx_control = __set_ctrl_super(chan, L2CAP_SUPER_RR);
-               l2cap_send_sframe(chan, rx_control);
-       }
-}
-
-static inline int l2cap_data_channel_sframe(struct l2cap_chan *chan, u32 rx_control, struct sk_buff *skb)
-{
-       BT_DBG("chan %p rx_control 0x%8.8x len %d", chan, rx_control, skb->len);
+               if (chan->sdu) {
+                       kfree_skb(chan->sdu);
+                       chan->sdu = NULL;
+               }
+               chan->sdu_last_frag = NULL;
+               chan->sdu_len = 0;
 
-       if (__is_ctrl_final(chan, rx_control) &&
-                       test_bit(CONN_WAIT_F, &chan->conn_state)) {
-               __clear_monitor_timer(chan);
-               if (chan->unacked_frames > 0)
-                       __set_retrans_timer(chan);
-               clear_bit(CONN_WAIT_F, &chan->conn_state);
+               if (skb) {
+                       BT_DBG("Freeing %p", skb);
+                       kfree_skb(skb);
+               }
        }
 
-       switch (__get_ctrl_super(chan, rx_control)) {
-       case L2CAP_SUPER_RR:
-               l2cap_data_channel_rrframe(chan, rx_control);
-               break;
-
-       case L2CAP_SUPER_REJ:
-               l2cap_data_channel_rejframe(chan, rx_control);
-               break;
-
-       case L2CAP_SUPER_SREJ:
-               l2cap_data_channel_srejframe(chan, rx_control);
-               break;
-
-       case L2CAP_SUPER_RNR:
-               l2cap_data_channel_rnrframe(chan, rx_control);
-               break;
-       }
+       chan->last_acked_seq = control->txseq;
+       chan->expected_tx_seq = __next_seq(chan, control->txseq);
 
-       kfree_skb(skb);
-       return 0;
+       return err;
 }
 
-static int l2cap_ertm_data_rcv(struct l2cap_chan *chan, struct sk_buff *skb)
+static int l2cap_data_rcv(struct l2cap_chan *chan, struct sk_buff *skb)
 {
-       u32 control;
-       u16 req_seq;
-       int len, next_tx_seq_offset, req_seq_offset;
+       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)
@@ -4578,34 +5155,57 @@ 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);
-               goto drop;
-       }
-
-       if (!__is_sframe(chan, control)) {
-               if (len < 0) {
-                       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 (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;
@@ -4618,9 +5218,6 @@ drop:
 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) {
@@ -4650,44 +5247,8 @@ 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: