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, 6 insertions, 4 deletions

diff --git a/drivers/net/wireless/ath/ath5k/desc.c b/drivers/net/wireless/ath/ath5k/desc.c
index dc30a2b..d26126b 100644
--- a/drivers/net/wireless/ath/ath5k/desc.c
+++ b/drivers/net/wireless/ath/ath5k/desc.c
@@ -35,7 +35,8 @@
  */
 static int
 ath5k_hw_setup_2word_tx_desc(struct ath5k_hw *ah, struct ath5k_desc *desc,
-	unsigned int pkt_len, unsigned int hdr_len, enum ath5k_pkt_type type,
+	unsigned int pkt_len, unsigned int hdr_len, int padsize,
+	enum ath5k_pkt_type type,
 	unsigned int tx_power, unsigned int tx_rate0, unsigned int tx_tries0,
 	unsigned int key_index, unsigned int antenna_mode, unsigned int flags,
 	unsigned int rtscts_rate, unsigned int rtscts_duration)
@@ -71,7 +72,7 @@ ath5k_hw_setup_2word_tx_desc(struct ath5k_hw *ah, struct ath5k_desc *desc,
 	/* Verify and set frame length */
 
 	/* remove padding we might have added before */
-	frame_len = pkt_len - ath5k_pad_size(hdr_len) + FCS_LEN;
+	frame_len = pkt_len - padsize + FCS_LEN;
 
 	if (frame_len & ~AR5K_2W_TX_DESC_CTL0_FRAME_LEN)
 		return -EINVAL;
@@ -100,7 +101,7 @@ ath5k_hw_setup_2word_tx_desc(struct ath5k_hw *ah, struct ath5k_desc *desc,
 			AR5K_REG_SM(hdr_len, AR5K_2W_TX_DESC_CTL0_HEADER_LEN);
 	}
 
-	/*Diferences between 5210-5211*/
+	/*Differences between 5210-5211*/
 	if (ah->ah_version == AR5K_AR5210) {
 		switch (type) {
 		case AR5K_PKT_TYPE_BEACON:
@@ -165,6 +166,7 @@ ath5k_hw_setup_2word_tx_desc(struct ath5k_hw *ah, struct ath5k_desc *desc,
  */
 static int ath5k_hw_setup_4word_tx_desc(struct ath5k_hw *ah,
 	struct ath5k_desc *desc, unsigned int pkt_len, unsigned int hdr_len,
+	int padsize,
 	enum ath5k_pkt_type type, unsigned int tx_power, unsigned int tx_rate0,
 	unsigned int tx_tries0, unsigned int key_index,
 	unsigned int antenna_mode, unsigned int flags,
@@ -206,7 +208,7 @@ static int ath5k_hw_setup_4word_tx_desc(struct ath5k_hw *ah,
 	/* Verify and set frame length */
 
 	/* remove padding we might have added before */
-	frame_len = pkt_len - ath5k_pad_size(hdr_len) + FCS_LEN;
+	frame_len = pkt_len - padsize + FCS_LEN;
 
 	if (frame_len & ~AR5K_4W_TX_DESC_CTL0_FRAME_LEN)
 		return -EINVAL;