2014-08-14 07:35:34

by Lukasz Rymanowski

Subject: [PATCH v2] Bluetooth: Fix ERTM L2CAP resend packet

I-Frame which is going to be resend already has FCS field added and set
(if it was required). Adding additional FCS field calculated from data +
old FCS in resend function is incorrect.

This patch fix that.

Issue has been found during PTS testing.

Signed-off-by: Lukasz Rymanowski <[email protected]>
---
net/bluetooth/l2cap_core.c | 8 +++++---
1 file changed, 5 insertions(+), 3 deletions(-)

diff --git a/net/bluetooth/l2cap_core.c b/net/bluetooth/l2cap_core.c
index ebe7454..43e2d74 100644
--- a/net/bluetooth/l2cap_core.c
+++ b/net/bluetooth/l2cap_core.c
@@ -1968,10 +1968,12 @@ static void l2cap_ertm_resend(struct l2cap_chan *chan)
tx_skb->data + L2CAP_HDR_SIZE);
}

+ /* Update FCS */
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));
+ u16 fcs = crc16(0, (u8 *)tx_skb->data, tx_skb->len -
+ L2CAP_FCS_SIZE);
+ put_unaligned_le16(fcs, skb_tail_pointer(tx_skb) -
+ L2CAP_FCS_SIZE);
}

l2cap_do_send(chan, tx_skb);
--
1.8.4

2014-08-14 07:48:27

by Marcel Holtmann

Subject: Re: [PATCH v2] Bluetooth: Fix ERTM L2CAP resend packet

Hi Lukasz,

> I-Frame which is going to be resend already has FCS field added and set
> (if it was required). Adding additional FCS field calculated from data +
> old FCS in resend function is incorrect.
>
> This patch fix that.
>
> Issue has been found during PTS testing.
>
> Signed-off-by: Lukasz Rymanowski <[email protected]>
> ---
> net/bluetooth/l2cap_core.c | 8 +++++---
> 1 file changed, 5 insertions(+), 3 deletions(-)

patch has been applied to bluetooth-next tree.

Regards

Marcel