mac80211: select and adjust bitrates according to channel mode

The various components accessing the bitrates table must use consider
the used channel bandwidth to select only available rates or calculate
the bitrate correctly.

There are some rates in reduced bandwidth modes which can't be
represented as multiples of 500kbps, like 2.25 MBit/s in 5 MHz mode. The
standard suggests to round up to the next multiple of 500kbps, just do
that in mac80211 as well.

Signed-off-by: Simon Wunderlich <siwu@hrz.tu-chemnitz.de>
Signed-off-by: Mathias Kretschmer <mathias.kretschmer@fokus.fraunhofer.de>
[make rate unsigned in ieee80211_add_tx_radiotap_header(), squash fix]
Signed-off-by: Johannes Berg <johannes@sipsolutions.net>

1 files changed, 22 insertions, 24 deletions

diff --git a/net/mac80211/rate.c b/net/mac80211/rate.c
index 30d58d2..ba63ac8 100644
--- a/net/mac80211/rate.c
+++ b/net/mac80211/rate.c
@@ -232,37 +232,28 @@ 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)
+static void __rate_control_send_low(struct ieee80211_hw *hw,
+				    struct ieee80211_supported_band *sband,
+				    struct ieee80211_sta *sta,
+				    struct ieee80211_tx_info *info)
 {
 	int i;
+	u32 rate_flags =
+		ieee80211_chandef_rate_flags(&hw->conf.chandef);
 
+	if ((sband->band == IEEE80211_BAND_2GHZ) &&
+	    (info->flags & IEEE80211_TX_CTL_NO_CCK_RATE))
+		rate_flags |= IEEE80211_RATE_ERP_G;
+
+	info->control.rates[0].idx = 0;
 	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))
+		if (!rate_supported(sta, sband->band, i))
 			continue;
 
-		if (rate_supported(sta, sband->band, i))
-			return i;
+		info->control.rates[0].idx = i;
+		break;
 	}
-
-	/* No matching rate found */
-	return 0;
-}
-
-static void __rate_control_send_low(struct ieee80211_hw *hw,
-				    struct ieee80211_supported_band *sband,
-				    struct ieee80211_sta *sta,
-				    struct ieee80211_tx_info *info)
-{
-	if ((sband->band != IEEE80211_BAND_2GHZ) ||
-	    !(info->flags & IEEE80211_TX_CTL_NO_CCK_RATE))
-		info->control.rates[0].idx = rate_lowest_index(sband, sta);
-	else
-		info->control.rates[0].idx =
-			rate_lowest_non_cck_index(sband, sta);
+	WARN_ON_ONCE(i == sband->n_bitrates);
 
 	info->control.rates[0].count =
 		(info->flags & IEEE80211_TX_CTL_NO_ACK) ?
@@ -585,6 +576,7 @@ static void rate_control_apply_mask(struct ieee80211_sub_if_data *sdata,
 	u8 mcs_mask[IEEE80211_HT_MCS_MASK_LEN];
 	bool has_mcs_mask;
 	u32 mask;
+	u32 rate_flags;
 	int i;
 
 	/*
@@ -594,6 +586,12 @@ static void rate_control_apply_mask(struct ieee80211_sub_if_data *sdata,
 	 */
 	mask = sdata->rc_rateidx_mask[info->band];
 	has_mcs_mask = sdata->rc_has_mcs_mask[info->band];
+	rate_flags =
+		ieee80211_chandef_rate_flags(&sdata->vif.bss_conf.chandef);
+	for (i = 0; i < sband->n_bitrates; i++)
+		if ((rate_flags & sband->bitrates[i].flags) != rate_flags)
+			mask &= ~BIT(i);
+
 	if (mask == (1 << sband->n_bitrates) - 1 && !has_mcs_mask)
 		return;