ieee80211: document DS bit usage
authorJohannes Berg <johannes@sipsolutions.net>
Sat, 14 Mar 2009 18:10:51 +0000 (19:10 +0100)
committerJohn W. Linville <linville@tuxdriver.com>
Sat, 28 Mar 2009 00:12:54 +0000 (20:12 -0400)
I keep needing this because I'm too stupid to remember it.
Everybody else can probably remember, but who knows :)

Signed-off-by: Johannes Berg <johannes@sipsolutions.net>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
include/linux/ieee80211.h

index b1bb817d1427875a4ddc2923084fb9dfebc65b57..382387e75b8912a1cd7fb63c4a6654d929b5e0b6 100644 (file)
 #include <linux/types.h>
 #include <asm/byteorder.h>
 
+/*
+ * DS bit usage
+ *
+ * TA = transmitter address
+ * RA = receiver address
+ * DA = destination address
+ * SA = source address
+ *
+ * ToDS    FromDS  A1(RA)  A2(TA)  A3      A4      Use
+ * -----------------------------------------------------------------
+ *  0       0       DA      SA      BSSID   -       IBSS/DLS
+ *  0       1       DA      BSSID   SA      -       AP -> STA
+ *  1       0       BSSID   SA      DA      -       AP <- STA
+ *  1       1       RA      TA      DA      SA      unspecified (WDS)
+ */
+
 #define FCS_LEN 4
 
 #define IEEE80211_FCTL_VERS            0x0003