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

PATCH New Andriy Tkachuk 1 participant 1 message Jan 20, 2010 802.11 (including cfg80211/NL80211)

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Andriy Tkachuk

author

2010-01-20 10:38 UTC #0 lore raw

PATCH 1/1 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 <[email protected]>

Acked-by Benoit Papillault <[email protected]>

---
 include/linux/ieee80211.h |    2 ++
 net/wireless/util.c       |    5 ++++-
 2 files changed, 6 insertions(+), 1 deletions(-)

include/linux/ieee80211.h +2 -0

index 8427019..1998495 100644
@@ -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;

net/wireless/util.c +4 -1

index 23557c1..be2ab8c 100644
@@ -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;
        }