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

[Ivo van Doorn <ivdoorn@gmail.com>]

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.

Ivo