Jouni Malinen wrote:
TKIP/CCMP are required to use incrementing TSC/PN for each frame. When a
directed IEEE 802.11 frame is not acknowledged, it will be retransmitted
(up to a certain limit). This retransmitted frame will use the same
TSC/PN. However, the duplicate detection routine in the receiver
(something that happens before TKIP/CCMP processing) should catch these
cases since the frames from the same source address that use the same
seq# and fragm# should be dropped at that layer.
If it can be shown, that these errors are indeed caused by a broken
transmitter (and that transmitter is not a Linux device for which we
control the driver code ;-), I would be much more willing to accept
patches that silence these messages (as long as the replay statistics
are easily available in other ways) by default, but I would still not
remove them completely.
I added the following patch to bcm43xx:
Index: wireless-2.6/drivers/net/wireless/bcm43xx/bcm43xx_xmit.c
===================================================================
--- wireless-2.6.orig/drivers/net/wireless/bcm43xx/bcm43xx_xmit.c
+++ wireless-2.6/drivers/net/wireless/bcm43xx/bcm43xx_xmit.c
@@ -460,6 +460,9 @@ static s8 bcm43xx_rssinoise_postprocess(
}
#endif
+static u16 prev_frame = 0;
+static u16 prev_seq = 0;
+
int bcm43xx_rx(struct bcm43xx_private *bcm,
struct sk_buff *skb,
struct bcm43xx_rxhdr *rxhdr)
@@ -470,6 +473,7 @@ int bcm43xx_rx(struct bcm43xx_private *b
struct ieee80211_rx_stats stats;
struct ieee80211_hdr_4addr *wlhdr;
u16 frame_ctl;
+ u16 seq_ctl;
int is_packet_for_us = 0;
int err = -EINVAL;
const u16 rxflags1 = le16_to_cpu(rxhdr->flags1);
@@ -544,6 +548,14 @@ int bcm43xx_rx(struct bcm43xx_private *b
}
frame_ctl = le16_to_cpu(wlhdr->frame_ctl);
+ seq_ctl = le16_to_cpu(wlhdr->seq_ctl);
+
+ if ((frame_ctl == prev_frame) && (seq_ctl == prev_seq))
+ return -EINVAL;
+
+ prev_frame = frame_ctl;
+ prev_seq = seq_ctl;
+
if ((frame_ctl & IEEE80211_FCTL_PROTECTED) && !bcm->ieee->host_decrypt)
{
frame_ctl &= ~IEEE80211_FCTL_PROTECTED;
wlhdr->frame_ctl = cpu_to_le16(frame_ctl);
By dropping those packets with frame_ctl and seq_ctl the same as the values in the previous packet,
I was able to cut the number of TKIP replay messages, but some still come through. Is this what you
had in mind, or is there somewhere else that I should be looking?
Larry
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