mac80211: Account HT Control field in Data frame hdrlen according to 802.11n-2009

ieee80211_hdrlen() should account account new HT Control field in 802.11
data frame header introduced by IEEE 802.11n standard.

According to 802.11n-2009 HT Control field is present in data frames
when both of following are met:

   1. It is QoS data frame.
   2. Order bit is set in Frame Control field.

The change might be totally compatible with legacy non-11n aware frames,
because 802.11-2007 standard states that "all QoS STAs set this subfield
to 0".

Signed-off-by: Andriy V. Tkachuk <andrit@ukr.net>
Acked-by : Benoit Papillault <benoit.papillault@free.fr>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

diff --git a/include/linux/ieee80211.h b/include/linux/ieee80211.h
index 8427019..1998495 100644 (file)
--- a/include/linux/ieee80211.h
+++ b/include/linux/ieee80211.h
@@ -138,6 +138,8 @@
 #define IEEE80211_WMM_IE_STA_QOSINFO_SP_MASK   0x03
 #define IEEE80211_WMM_IE_STA_QOSINFO_SP_SHIFT  5
 
+#define IEEE80211_HT_CTL_LEN           4
+
 struct ieee80211_hdr {
        __le16 frame_control;
        __le16 duration_id;

diff --git a/net/wireless/util.c b/net/wireless/util.c
index 23557c1..be2ab8c 100644 (file)
--- a/net/wireless/util.c
+++ b/net/wireless/util.c
@@ -227,8 +227,11 @@ unsigned int ieee80211_hdrlen(__le16 fc)
        if (ieee80211_is_data(fc)) {
                if (ieee80211_has_a4(fc))
                        hdrlen = 30;
-               if (ieee80211_is_data_qos(fc))
+               if (ieee80211_is_data_qos(fc)) {
                        hdrlen += IEEE80211_QOS_CTL_LEN;
+                       if (ieee80211_has_order(fc))
+                               hdrlen += IEEE80211_HT_CTL_LEN;
+               }
                goto out;
        }