When running a monitor interface with ath5k, the FCS of ACK
frames is two bytes short. The reason is that unlike the
payload, the FCS doesn't seem to aligned to a 4 byte boundary
by the chip, the attempt to remove the padding corrupts it.
This patch checks whether there actually is any payload after
the header (besides the FCS) before removing the padding.
This might not be fully correct or not handle other cases where
this can occur, but it doesn't seem too hackish and fixes the
problem for me :)
http://bugzilla.kernel.org/show_bug.cgi?id=12101
commit 8c1d598338077d397aed25fe4840e4d4b51ba79c
Author: Patrick McHardy <kaber@xxxxxxxxx>
Date: Tue Dec 9 21:52:00 2008 +0100
atk5k: fix FCS corruption for ACKs
The trailing FCS value is not aliged when no payload is present. Don't try
to remove padding to avoid corrupting it.
Kernel Bugzilla #12101
Signed-off-by: Patrick McHardy <kaber@xxxxxxxxx>
diff --git a/drivers/net/wireless/ath5k/base.c b/drivers/net/wireless/ath5k/base.c
index d9e1980..940c724 100644
--- a/drivers/net/wireless/ath5k/base.c
+++ b/drivers/net/wireless/ath5k/base.c
@@ -1752,7 +1752,7 @@ accept:
* not multiples of 4 - remove it
*/
hdrlen = ieee80211_get_hdrlen_from_skb(skb);
- if (hdrlen & 3) {
+ if (hdrlen & 3 && hdrlen != rs.rs_datalen - FCS_LEN) {
pad = hdrlen % 4;
memmove(skb->data + pad, skb->data, hdrlen);
skb_pull(skb, pad);
