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authorGustavo F. Padovan <gustavo@las.ic.unicamp.br>2009-08-20 22:25:59 -0300
committerMarcel Holtmann <marcel@holtmann.org>2009-08-22 14:55:20 -0700
commit30afb5b2aa83adf4f69e5090d48e1bb04b64c58a (patch)
treef47506c5f02b8e1d23123cadee49f518c928afa5
parentc74e560cd0101455f1889515e1527e4c2e266113 (diff)
Bluetooth: Initial support for retransmission of packets with REJ frames
When receiving an I-frame with unexpected txSeq, receiver side start the recovery procedure by sending a REJ S-frame to the transmitter side. So the transmitter can re-send the lost I-frame. This patch just adds a basic support for retransmission, it doesn't mean that ERTM now has full support for packet retransmission. Signed-off-by: Gustavo F. Padovan <gustavo@las.ic.unicamp.br> Signed-off-by: Marcel Holtmann <marcel@holtmann.org>
-rw-r--r--include/net/bluetooth/l2cap.h1
-rw-r--r--net/bluetooth/l2cap.c57
2 files changed, 44 insertions, 14 deletions
diff --git a/include/net/bluetooth/l2cap.h b/include/net/bluetooth/l2cap.h
index 0afde8d22b5..a1d8ec468ef 100644
--- a/include/net/bluetooth/l2cap.h
+++ b/include/net/bluetooth/l2cap.h
@@ -351,6 +351,7 @@ struct l2cap_pinfo {
#define L2CAP_CONF_MAX_CONF_RSP 2
#define L2CAP_CONN_SAR_SDU 0x01
+#define L2CAP_CONN_UNDER_REJ 0x02
static inline int l2cap_tx_window_full(struct sock *sk)
{
diff --git a/net/bluetooth/l2cap.c b/net/bluetooth/l2cap.c
index 167e0253269..35e9f5b8054 100644
--- a/net/bluetooth/l2cap.c
+++ b/net/bluetooth/l2cap.c
@@ -2951,22 +2951,36 @@ static inline int l2cap_data_channel_iframe(struct sock *sk, u16 rx_control, str
BT_DBG("sk %p rx_control 0x%4.4x len %d", sk, rx_control, skb->len);
- if (tx_seq != pi->expected_tx_seq)
- return -EINVAL;
+ if (tx_seq == pi->expected_tx_seq) {
+ if (pi->conn_state & L2CAP_CONN_UNDER_REJ)
+ pi->conn_state &= ~L2CAP_CONN_UNDER_REJ;
- err = l2cap_sar_reassembly_sdu(sk, skb, rx_control);
- if (err < 0)
- return err;
+ err = l2cap_sar_reassembly_sdu(sk, skb, rx_control);
+ if (err < 0)
+ return err;
+
+ pi->expected_tx_seq = (pi->expected_tx_seq + 1) % 64;
+ pi->num_to_ack = (pi->num_to_ack + 1) % L2CAP_DEFAULT_NUM_TO_ACK;
+ if (pi->num_to_ack == L2CAP_DEFAULT_NUM_TO_ACK - 1) {
+ tx_control |= L2CAP_SUPER_RCV_READY;
+ tx_control |= pi->expected_tx_seq << L2CAP_CTRL_REQSEQ_SHIFT;
+ goto send;
+ }
+ } else {
+ /* Unexpected txSeq. Send a REJ S-frame */
+ kfree_skb(skb);
+ if (!(pi->conn_state & L2CAP_CONN_UNDER_REJ)) {
+ tx_control |= L2CAP_SUPER_REJECT;
+ tx_control |= pi->expected_tx_seq << L2CAP_CTRL_REQSEQ_SHIFT;
+ pi->conn_state |= L2CAP_CONN_UNDER_REJ;
- pi->expected_tx_seq = (pi->expected_tx_seq + 1) % 64;
- pi->num_to_ack = (pi->num_to_ack + 1) % L2CAP_DEFAULT_NUM_TO_ACK;
- if (pi->num_to_ack == L2CAP_DEFAULT_NUM_TO_ACK - 1) {
- tx_control |= L2CAP_CTRL_FRAME_TYPE;
- tx_control |= L2CAP_SUPER_RCV_READY;
- tx_control |= pi->expected_tx_seq << L2CAP_CTRL_REQSEQ_SHIFT;
- err = l2cap_send_sframe(pi, tx_control);
+ goto send;
+ }
}
- return err;
+ return 0;
+
+send:
+ return l2cap_send_sframe(pi, tx_control);
}
static inline int l2cap_data_channel_sframe(struct sock *sk, u16 rx_control, struct sk_buff *skb)
@@ -2982,8 +2996,18 @@ static inline int l2cap_data_channel_sframe(struct sock *sk, u16 rx_control, str
l2cap_ertm_send(sk);
break;
- case L2CAP_SUPER_RCV_NOT_READY:
case L2CAP_SUPER_REJECT:
+ pi->expected_ack_seq = __get_reqseq(rx_control);
+ l2cap_drop_acked_frames(sk);
+
+ sk->sk_send_head = TX_QUEUE(sk)->next;
+ pi->next_tx_seq = pi->expected_ack_seq;
+
+ l2cap_ertm_send(sk);
+
+ break;
+
+ case L2CAP_SUPER_RCV_NOT_READY:
case L2CAP_SUPER_SELECT_REJECT:
break;
}
@@ -3030,6 +3054,11 @@ static inline int l2cap_data_channel(struct l2cap_conn *conn, u16 cid, struct sk
if (__is_sar_start(control))
len -= 2;
+ /*
+ * We can just drop the corrupted I-frame here.
+ * Receiver will miss it and start proper recovery
+ * procedures and ask retransmission.
+ */
if (len > L2CAP_DEFAULT_MAX_PDU_SIZE)
goto drop;