ath5k: Fix TX/RX padding for all frames

Currently, the padding position is based on
ieee80211_get_hdrlen_from_skb(). This is not correct since the HW does
padding on RX (and expect the same padding to be present on TX) at the
following position :

- management : 24 + 6 if 4-addr format
- control    : 24 + 6 if 4-addr format
- data       : 24 + 6 if 4-addr format + 2 if QoS
- invalid    : 24 + 6 if 4-addr format

whereas ieee80211_get_hdrlen_from_skb() is :

- management : 24
- control    : 16 except for ACK/CTS where it is 10
- data       : 24 + 6 if 4-addr format + 2 if QoS + 2 if QoS & order
- invalid    : 24

So, correct frames are not affected : management frames do not use
4-addr format, control frames have no body and invalid frames are ...
not valid by definition. However, in order to use monitor interface for
debugging purpose, one must be able to send/receive any frames, be it
correct or not. Such frames are affected by incorrect padding.

Moreover, since padding is added on TX, we need to remove it before
calling ieee80211_tx_status. This affect TX packets received by monitor
interfaces.

It has been tested between an ath5k based card (AR5212) and an ar9170usb
based card (netgear WNDA3100) using a frame generator and a monitor
interface for each card.

v2: Added ath5k_add_padding / ath5k_remove_padding

Signed-off-by: Benoit Papillault <benoit.papillault@free.fr>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

1 files changed, 2 insertions, 7 deletions

diff --git a/drivers/net/wireless/ath/ath5k/ath5k.h b/drivers/net/wireless/ath/ath5k/ath5k.h
index 4de7fe03b9f..22f9f59397c 100644
--- a/drivers/net/wireless/ath/ath5k/ath5k.h
+++ b/drivers/net/wireless/ath/ath5k/ath5k.h
@@ -1141,9 +1141,9 @@ struct ath5k_hw {
 	int (*ah_setup_rx_desc)(struct ath5k_hw *ah, struct ath5k_desc *desc,
 				u32 size, unsigned int flags);
 	int (*ah_setup_tx_desc)(struct ath5k_hw *, struct ath5k_desc *,
-		unsigned int, unsigned int, enum ath5k_pkt_type, unsigned int,
+		unsigned int, unsigned int, int, enum ath5k_pkt_type,
 		unsigned int, unsigned int, unsigned int, unsigned int,
-		unsigned int, unsigned int, unsigned int);
+		unsigned int, unsigned int, unsigned int, unsigned int);
 	int (*ah_setup_mrr_tx_desc)(struct ath5k_hw *, struct ath5k_desc *,
 		unsigned int, unsigned int, unsigned int, unsigned int,
 		unsigned int, unsigned int);
@@ -1342,9 +1342,4 @@ static inline u32 ath5k_hw_bitswap(u32 val, unsigned int bits)
 	return retval;
 }
 
-static inline int ath5k_pad_size(int hdrlen)
-{
-	return (hdrlen < 24) ? 0 : hdrlen & 3;
-}
-
 #endif