mac80211: Send the management frame at requested rate

Whenever the scan request or tx_mgmt is requesting not to
use CCK rate for managemet frames through
NL80211_ATTR_TX_NO_CCK_RATE attribute, then mac80211 should
select appropriate least non-CCK rate. This could help to
send P2P probes and P2P action frames at non 11b rates
without diabling 11b rates globally.

Cc: Jouni Malinen <jouni@qca.qualcomm.com>
Signed-off-by: Rajkumar Manoharan <rmanohar@qca.qualcomm.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

1 files changed, 28 insertions, 1 deletions

diff --git a/net/mac80211/rate.c b/net/mac80211/rate.c
index 3d5a2cb835c4..f61244c0e0a2 100644
--- a/net/mac80211/rate.c
+++ b/net/mac80211/rate.c
@@ -233,6 +233,27 @@ static void rc_send_low_broadcast(s8 *idx, u32 basic_rates,
         /* could not find a basic rate; use original selection */
 }
 
+static inline s8
+rate_lowest_non_cck_index(struct ieee80211_supported_band *sband,
+                          struct ieee80211_sta *sta)
+{
+        int i;
+
+        for (i = 0; i < sband->n_bitrates; i++) {
+                struct ieee80211_rate *srate = &sband->bitrates[i];
+                if ((srate->bitrate == 10) || (srate->bitrate == 20) ||
+                    (srate->bitrate == 55) || (srate->bitrate == 110))
+                        continue;
+
+                if (rate_supported(sta, sband->band, i))
+                        return i;
+        }
+
+        /* No matching rate found */
+        return 0;
+}
+
+
 bool rate_control_send_low(struct ieee80211_sta *sta,
                            void *priv_sta,
                            struct ieee80211_tx_rate_control *txrc)
@@ -242,7 +263,13 @@ bool rate_control_send_low(struct ieee80211_sta *sta,
         int mcast_rate;
 
         if (!sta || !priv_sta || rc_no_data_or_no_ack(txrc)) {
-                info->control.rates[0].idx = rate_lowest_index(txrc->sband, sta);
+                if ((sband->band != IEEE80211_BAND_2GHZ) ||
+                    !(info->flags & IEEE80211_TX_CTL_NO_CCK_RATE))
+                        info->control.rates[0].idx =
+                                rate_lowest_index(txrc->sband, sta);
+                else
+                        info->control.rates[0].idx =
+                                rate_lowest_non_cck_index(txrc->sband, sta);
                 info->control.rates[0].count =
                         (info->flags & IEEE80211_TX_CTL_NO_ACK) ?
                         1 : txrc->hw->max_rate_tries;