ath5k: fix 802.11 header padding on RX, unpadding on TX
Padding the 802.11 header to a multiple of 4 bytes needs to be done only for
frames with a body. This fixes a bug where 2 bytes were missing in monitor
mode for ACK frames. Inspired by a patch from Jouni Malinen on ath9k.
Ref: http://bugzilla.kernel.org/show_bug.cgi?id=12101 :
Signed-off-by: Benoit Papillault <benoit.papillault@free.fr>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
diff --git a/drivers/net/wireless/ath5k/base.c b/drivers/net/wireless/ath5k/base.c
index 0e43170..9b5f31a 100644
--- a/drivers/net/wireless/ath5k/base.c
+++ b/drivers/net/wireless/ath5k/base.c
@@ -1668,7 +1668,7 @@
struct ath5k_desc *ds;
int ret;
int hdrlen;
- int pad;
+ int padsize;
spin_lock(&sc->rxbuflock);
if (list_empty(&sc->rxbuf)) {
@@ -1753,16 +1753,19 @@
skb_put(skb, rs.rs_datalen);
- /*
- * the hardware adds a padding to 4 byte boundaries between
- * the header and the payload data if the header length is
- * not multiples of 4 - remove it
- */
+ /* The MAC header is padded to have 32-bit boundary if the
+ * packet payload is non-zero. The general calculation for
+ * padsize would take into account odd header lengths:
+ * padsize = (4 - hdrlen % 4) % 4; However, since only
+ * even-length headers are used, padding can only be 0 or 2
+ * bytes and we can optimize this a bit. In addition, we must
+ * not try to remove padding from short control frames that do
+ * not have payload. */
hdrlen = ieee80211_get_hdrlen_from_skb(skb);
- if (hdrlen & 3) {
- pad = hdrlen % 4;
- memmove(skb->data + pad, skb->data, hdrlen);
- skb_pull(skb, pad);
+ padsize = hdrlen & 3;
+ if (padsize && hdrlen >= 24) {
+ memmove(skb->data + padsize, skb->data, hdrlen);
+ skb_pull(skb, padsize);
}
/*
@@ -2623,7 +2626,7 @@
struct ath5k_buf *bf;
unsigned long flags;
int hdrlen;
- int pad;
+ int padsize;
ath5k_debug_dump_skb(sc, skb, "TX ", 1);
@@ -2635,15 +2638,16 @@
* if this is not the case we add the padding after the header
*/
hdrlen = ieee80211_get_hdrlen_from_skb(skb);
- if (hdrlen & 3) {
- pad = hdrlen % 4;
- if (skb_headroom(skb) < pad) {
+ padsize = hdrlen & 3;
+ if (padsize && hdrlen >= 24) {
+
+ if (skb_headroom(skb) < padsize) {
ATH5K_ERR(sc, "tx hdrlen not %%4: %d not enough"
- " headroom to pad %d\n", hdrlen, pad);
+ " headroom to pad %d\n", hdrlen, padsize);
return -1;
}
- skb_push(skb, pad);
- memmove(skb->data, skb->data+pad, hdrlen);
+ skb_push(skb, padsize);
+ memmove(skb->data, skb->data+padsize, hdrlen);
}
spin_lock_irqsave(&sc->txbuflock, flags);