From e1fbd4c19a5c4d4f490d70e73745cf2cf0dc1955 Mon Sep 17 00:00:00 2001 From: Mat Martineau Date: Thu, 17 May 2012 20:53:43 -0700 Subject: [PATCH] Bluetooth: Add implementation for retransmitting all unacked frames This adds l2cap_ertm_resend to retransmit frames based on the sequence numbers in chan->retrans_list. If the retransmit limit is reached for any individual frame is reached, the connection is dropped. skbs that are cloned already are copied to avoid modifying shared data (this is uncommon). To retransmit all frames, l2cap_retransmit_all now builds a list of all unacked sequence numbers and then calls l2cap_ertm_resend. Signed-off-by: Mat Martineau Signed-off-by: Gustavo Padovan --- net/bluetooth/l2cap_core.c | 106 ++++++++++++++++++++++++++++++++++++- 1 file changed, 105 insertions(+), 1 deletion(-) diff --git a/net/bluetooth/l2cap_core.c b/net/bluetooth/l2cap_core.c index 287d64cf2dd4..26963a5e3f58 100644 --- a/net/bluetooth/l2cap_core.c +++ b/net/bluetooth/l2cap_core.c @@ -1760,10 +1760,114 @@ static int l2cap_ertm_send(struct l2cap_chan *chan) return sent; } +static void l2cap_ertm_resend(struct l2cap_chan *chan) +{ + struct l2cap_ctrl control; + struct sk_buff *skb; + struct sk_buff *tx_skb; + u16 seq; + + BT_DBG("chan %p", chan); + + if (test_bit(CONN_REMOTE_BUSY, &chan->conn_state)) + return; + + while (chan->retrans_list.head != L2CAP_SEQ_LIST_CLEAR) { + seq = l2cap_seq_list_pop(&chan->retrans_list); + + skb = l2cap_ertm_seq_in_queue(&chan->tx_q, seq); + if (!skb) { + BT_DBG("Error: Can't retransmit seq %d, frame missing", + seq); + continue; + } + + bt_cb(skb)->control.retries++; + control = bt_cb(skb)->control; + + 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.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); + } + + if (!tx_skb) { + l2cap_seq_list_clear(&chan->retrans_list); + break; + } + + /* 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) { + 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); + + BT_DBG("Resent txseq %d", control.txseq); + + chan->last_acked_seq = chan->buffer_seq; + } +} + static void l2cap_retransmit_all(struct l2cap_chan *chan, struct l2cap_ctrl *control) { - /* Placeholder */ + struct sk_buff *skb; + + BT_DBG("chan %p, control %p", chan, control); + + if (control->poll) + set_bit(CONN_SEND_FBIT, &chan->conn_state); + + l2cap_seq_list_clear(&chan->retrans_list); + + if (test_bit(CONN_REMOTE_BUSY, &chan->conn_state)) + return; + + 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) -- 2.39.5