[PATCH 3/3] mac80211: Add HT rates into radiotap

[Jouni Malinen <jouni.malinen@atheros.com>]

Update the radiotap definition based on the format used in FreeBSD to
allows MCS index, HT20/HT40, and short GI information to be reported
for received frames in monitor mode. This format is also supported by
wireshark.

Signed-off-by: Jouni Malinen <jouni.malinen@atheros.com>
---
 include/net/ieee80211_radiotap.h |    7 +++++--
 net/mac80211/rx.c                |   28 ++++++++++++----------------
 2 files changed, 17 insertions(+), 18 deletions(-)

--- wireless-testing.orig/include/net/ieee80211_radiotap.h	2008-12-04 12:56:59.000000000 +0200
+++ wireless-testing/include/net/ieee80211_radiotap.h	2008-12-12 14:10:02.000000000 +0200
@@ -100,9 +100,10 @@ struct ieee80211_radiotap_header {
  *      For frequency-hopping radios, the hop set (first byte)
  *      and pattern (second byte).
  *
- * IEEE80211_RADIOTAP_RATE              u8           500kb/s
+ * IEEE80211_RADIOTAP_RATE              u8           500kb/s or index
  *
- *      Tx/Rx data rate
+ *      Tx/Rx data rate.  If bit 0x80 is set then it represents an
+ *      an MCS index and not an IEEE rate.
  *
  * IEEE80211_RADIOTAP_DBM_ANTSIGNAL     s8           decibels from
  *                                                   one milliwatt (dBm)
@@ -230,6 +231,8 @@ enum ieee80211_radiotap_type {
 						 * 802.11 header and payload
 						 * (to 32-bit boundary)
 						 */
+#define	IEEE80211_RADIOTAP_F_SHORTGI	0x80	/* HT short GI */
+
 /* For IEEE80211_RADIOTAP_RX_FLAGS */
 #define IEEE80211_RADIOTAP_F_RX_BADFCS	0x0001	/* frame failed crc check */
 
--- wireless-testing.orig/net/mac80211/rx.c	2008-12-12 14:09:52.000000000 +0200
+++ wireless-testing/net/mac80211/rx.c	2008-12-12 14:10:02.000000000 +0200
@@ -116,6 +116,7 @@ ieee80211_add_rx_radiotap_header(struct 
 {
 	struct ieee80211_radiotap_header *rthdr;
 	unsigned char *pos;
+	u16 chan_flags;
 
 	rthdr = (struct ieee80211_radiotap_header *)skb_push(skb, rtap_len);
 	memset(rthdr, 0, rtap_len);
@@ -146,19 +147,14 @@ ieee80211_add_rx_radiotap_header(struct 
 		*pos |= IEEE80211_RADIOTAP_F_FCS;
 	if (status->flag & RX_FLAG_SHORTPRE)
 		*pos |= IEEE80211_RADIOTAP_F_SHORTPRE;
+	if (status->flag & RX_FLAG_SHORT_GI)
+		*pos |= IEEE80211_RADIOTAP_F_SHORTGI;
 	pos++;
 
 	/* IEEE80211_RADIOTAP_RATE */
-	if (status->flag & RX_FLAG_HT) {
-		/*
-		 * TODO: add following information into radiotap header once
-		 * suitable fields are defined for it:
-		 * - MCS index (status->rate_idx)
-		 * - HT40 (status->flag & RX_FLAG_40MHZ)
-		 * - short-GI (status->flag & RX_FLAG_SHORT_GI)
-		 */
-		*pos = 0;
-	} else
+	if (status->flag & RX_FLAG_HT)
+		*pos = 0x80 | status->rate_idx;
+	else
 		*pos = rate->bitrate / 5;
 	pos++;
 
@@ -166,14 +162,14 @@ ieee80211_add_rx_radiotap_header(struct 
 	*(__le16 *)pos = cpu_to_le16(status->freq);
 	pos += 2;
 	if (status->band == IEEE80211_BAND_5GHZ)
-		*(__le16 *)pos = cpu_to_le16(IEEE80211_CHAN_OFDM |
-					     IEEE80211_CHAN_5GHZ);
+		chan_flags = IEEE80211_CHAN_OFDM | IEEE80211_CHAN_5GHZ;
 	else if (rate->flags & IEEE80211_RATE_ERP_G)
-		*(__le16 *)pos = cpu_to_le16(IEEE80211_CHAN_OFDM |
-					     IEEE80211_CHAN_2GHZ);
+		chan_flags = IEEE80211_CHAN_OFDM | IEEE80211_CHAN_2GHZ;
 	else
-		*(__le16 *)pos = cpu_to_le16(IEEE80211_CHAN_CCK |
-					     IEEE80211_CHAN_2GHZ);
+		chan_flags = IEEE80211_CHAN_CCK | IEEE80211_CHAN_2GHZ;
+	if (status->flag & RX_FLAG_40MHZ)
+		chan_flags |= IEEE80211_CHAN_TURBO;
+	*(__le16 *) pos = cpu_to_le16(chan_flags);
 	pos += 2;
 
 	/* IEEE80211_RADIOTAP_DBM_ANTSIGNAL */

-- 

-- 
Jouni Malinen                                            PGP id EFC895FA