[rt2x00-users] [PATCH v3 4/4] rt2x00: Only remove L2 padding in received frames if there is payload.

[Ivo Van Doorn]

On Tue, Dec 1, 2009 at 11:09 PM, Gertjan van Wingerde
<gwingerde at gmail.com> wrote:
> On 12/01/09 22:57, Ivo van Doorn wrote:
>> On Tuesday 01 December 2009, Gertjan van Wingerde wrote:
>>> On 12/01/09 20:16, Ivo van Doorn wrote:
>>>> On Monday 30 November 2009, Gertjan van Wingerde wrote:
>>>>> L2 padding will only be present when there is actual payload present.
>>>>>
>>>>> Signed-off-by: Gertjan van Wingerde <gwingerde at gmail.com>
>>>>> ---
>>>>>  drivers/net/wireless/rt2x00/rt2x00dev.c |    4 +++-
>>>>>  1 files changed, 3 insertions(+), 1 deletions(-)
>>>>>
>>>>> diff --git a/drivers/net/wireless/rt2x00/rt2x00dev.c b/drivers/net/wireless/rt2x00/rt2x00dev.c
>>>>> index ca2bcc0..b93731b 100644
>>>>> --- a/drivers/net/wireless/rt2x00/rt2x00dev.c
>>>>> +++ b/drivers/net/wireless/rt2x00/rt2x00dev.c
>>>>> @@ -401,7 +401,9 @@ void rt2x00lib_rxdone(struct rt2x00_dev *rt2x00dev,
>>>>>        (rxdesc.flags & RX_FLAG_IV_STRIPPED))
>>>>>            rt2x00crypto_rx_insert_iv(entry->skb, header_length,
>>>>>                                      &rxdesc);
>>>>> -  else if (rxdesc.dev_flags & RXDONE_L2PAD)
>>>>> +  else if (header_length &&
>>>>> +           (rxdesc.size > header_length) &&
>>>>> +           (rxdesc.dev_flags & RXDONE_L2PAD))
>>>>>            rt2x00queue_remove_l2pad(entry->skb, header_length);
>>>>>    else
>>>>>            rt2x00queue_align_payload(entry->skb, header_length);
>>>>
>>>> Is there a scenario where header_lenght can be 0?
>>>> And if there is, shouldn't we have bailed-out completely already?
>>>>
>>>
>>> Actually, there is. ieee80211_get_hdrlen_from_skb returns 0 when it detects that
>>> the skb is actually shorter than it should be (according to the frame type indicated
>>> by the frame_control field).
>>> I'm using that here to check whether actually any payload is present, as a value of 0
>>> means that there isn't even a full header.
>>> We should still pass on the frame in that case, for the monitor interfaces.
>>
>> Ok, then we should pass it to mac80211, but we better use a goto or something to
>> skip all frame manipulation (like the rt2x00crypto_rx_insert_iv and rt2x00queue_align_payload)
>> as well.
>>
>
> Good point. Can we do that as a follow-up patch?

Sure. :)

Ivo