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

[Gertjan van Wingerde <gwingerde@gmail.com>]

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@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?

---
Gertjan.