SREJ frame with P-bit set acknowledges I-frames numbered up to
(ReqSeq - 1). With this patch P-bit in SREJ is set only when there are
some I-frames to ack.
This fixes ambiguous situation when lost of I-frame with TxSeq=0 would
result in sending SREJ acking all previous I-frames.
Consider following scenario:
TxWindow=3
HostA: sent I-frame TxSeq=0
HostA: sent I-frame TxSeq=1
HostA: sent I-frame TxSeq=2
HostB: missed I-frame TxSeq=0
HostB: received I-frame TxSeq=1
HostB: sent SREJ ReqSeq=0 Pbit=1
HostA: received SREJ ReqSeq=0 Pbit=1 <- All I-frames acked or not?
...
Signed-off-by: Szymon Janc <szymon.janc@xxxxxxxxx>
---
net/bluetooth/l2cap_core.c | 6 +++---
1 files changed, 3 insertions(+), 3 deletions(-)
diff --git a/net/bluetooth/l2cap_core.c b/net/bluetooth/l2cap_core.c
index 97f8549..308d9d7 100644
--- a/net/bluetooth/l2cap_core.c
+++ b/net/bluetooth/l2cap_core.c
@@ -3927,15 +3927,15 @@ static inline int l2cap_data_channel_iframe(struct l2cap_chan *chan, u32 rx_cont
__skb_queue_head_init(&chan->srej_q);
l2cap_add_to_srej_queue(chan, skb, tx_seq, sar);
- set_bit(CONN_SEND_PBIT, &chan->conn_state);
+ /* 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);
err = l2cap_send_srejframe(chan, tx_seq);
if (err < 0) {
l2cap_send_disconn_req(chan->conn, chan, -err);
return err;
}
-
- __clear_ack_timer(chan);
}
return 0;
--
on behalf of ST-Ericsson
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