On Fri, Dec 12, 2008 at 1:38 PM, Jouni Malinen
<jouni.malinen@xxxxxxxxxxx> wrote:
> 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@xxxxxxxxxxx>
> ---
> 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
> --
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>
Thanks for the heads up, mail forwarded to Thomas d'Otreppe, as this
will need changes in airodump-ng.
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