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, 54 insertions, 41 deletions

diff --git a/net/mac80211/mlme.c b/net/mac80211/mlme.c
index ae31968d42d..f7552c2b74e 100644
--- a/net/mac80211/mlme.c
+++ b/net/mac80211/mlme.c
@@ -478,27 +478,6 @@ static int ieee80211_config_bw(struct ieee80211_sub_if_data *sdata,
 
 /* frame sending functions */
 
-static int ieee80211_compatible_rates(const u8 *supp_rates, int supp_rates_len,
-				      struct ieee80211_supported_band *sband,
-				      u32 *rates)
-{
-	int i, j, count;
-	*rates = 0;
-	count = 0;
-	for (i = 0; i < supp_rates_len; i++) {
-		int rate = (supp_rates[i] & 0x7F) * 5;
-
-		for (j = 0; j < sband->n_bitrates; j++)
-			if (sband->bitrates[j].bitrate == rate) {
-				*rates |= BIT(j);
-				count++;
-				break;
-			}
-	}
-
-	return count;
-}
-
 static void ieee80211_add_ht_ie(struct ieee80211_sub_if_data *sdata,
 				struct sk_buff *skb, u8 ap_ht_param,
 				struct ieee80211_supported_band *sband,
@@ -617,12 +596,12 @@ static void ieee80211_send_assoc(struct ieee80211_sub_if_data *sdata)
 	struct ieee80211_mgmt *mgmt;
 	u8 *pos, qos_info;
 	size_t offset = 0, noffset;
-	int i, count, rates_len, supp_rates_len;
+	int i, count, rates_len, supp_rates_len, shift;
 	u16 capab;
 	struct ieee80211_supported_band *sband;
 	struct ieee80211_chanctx_conf *chanctx_conf;
 	struct ieee80211_channel *chan;
-	u32 rates = 0;
+	u32 rate_flags, rates = 0;
 
 	sdata_assert_lock(sdata);
 
@@ -633,8 +612,10 @@ static void ieee80211_send_assoc(struct ieee80211_sub_if_data *sdata)
 		return;
 	}
 	chan = chanctx_conf->def.chan;
+	rate_flags = ieee80211_chandef_rate_flags(&chanctx_conf->def);
 	rcu_read_unlock();
 	sband = local->hw.wiphy->bands[chan->band];
+	shift = ieee80211_vif_get_shift(&sdata->vif);
 
 	if (assoc_data->supp_rates_len) {
 		/*
@@ -643,17 +624,24 @@ static void ieee80211_send_assoc(struct ieee80211_sub_if_data *sdata)
 		 * in the association request (e.g. D-Link DAP 1353 in
 		 * b-only mode)...
 		 */
-		rates_len = ieee80211_compatible_rates(assoc_data->supp_rates,
-						       assoc_data->supp_rates_len,
-						       sband, &rates);
+		rates_len = ieee80211_parse_bitrates(&chanctx_conf->def, sband,
+						     assoc_data->supp_rates,
+						     assoc_data->supp_rates_len,
+						     &rates);
 	} else {
 		/*
 		 * In case AP not provide any supported rates information
 		 * before association, we send information element(s) with
 		 * all rates that we support.
 		 */
-		rates = ~0;
-		rates_len = sband->n_bitrates;
+		rates_len = 0;
+		for (i = 0; i < sband->n_bitrates; i++) {
+			if ((rate_flags & sband->bitrates[i].flags)
+			    != rate_flags)
+				continue;
+			rates |= BIT(i);
+			rates_len++;
+		}
 	}
 
 	skb = alloc_skb(local->hw.extra_tx_headroom +
@@ -730,8 +718,9 @@ static void ieee80211_send_assoc(struct ieee80211_sub_if_data *sdata)
 	count = 0;
 	for (i = 0; i < sband->n_bitrates; i++) {
 		if (BIT(i) & rates) {
-			int rate = sband->bitrates[i].bitrate;
-			*pos++ = (u8) (rate / 5);
+			int rate = DIV_ROUND_UP(sband->bitrates[i].bitrate,
+						5 * (1 << shift));
+			*pos++ = (u8) rate;
 			if (++count == 8)
 				break;
 		}
@@ -744,8 +733,10 @@ static void ieee80211_send_assoc(struct ieee80211_sub_if_data *sdata)
 
 		for (i++; i < sband->n_bitrates; i++) {
 			if (BIT(i) & rates) {
-				int rate = sband->bitrates[i].bitrate;
-				*pos++ = (u8) (rate / 5);
+				int rate;
+				rate = DIV_ROUND_UP(sband->bitrates[i].bitrate,
+						    5 * (1 << shift));
+				*pos++ = (u8) rate;
 			}
 		}
 	}
@@ -2432,15 +2423,16 @@ static void ieee80211_get_rates(struct ieee80211_supported_band *sband,
 				u8 *supp_rates, unsigned int supp_rates_len,
 				u32 *rates, u32 *basic_rates,
 				bool *have_higher_than_11mbit,
-				int *min_rate, int *min_rate_index)
+				int *min_rate, int *min_rate_index,
+				int shift, u32 rate_flags)
 {
 	int i, j;
 
 	for (i = 0; i < supp_rates_len; i++) {
-		int rate = (supp_rates[i] & 0x7f) * 5;
+		int rate = supp_rates[i] & 0x7f;
 		bool is_basic = !!(supp_rates[i] & 0x80);
 
-		if (rate > 110)
+		if ((rate * 5 * (1 << shift)) > 110)
 			*have_higher_than_11mbit = true;
 
 		/*
@@ -2456,12 +2448,20 @@ static void ieee80211_get_rates(struct ieee80211_supported_band *sband,
 			continue;
 
 		for (j = 0; j < sband->n_bitrates; j++) {
-			if (sband->bitrates[j].bitrate == rate) {
+			struct ieee80211_rate *br;
+			int brate;
+
+			br = &sband->bitrates[j];
+			if ((rate_flags & br->flags) != rate_flags)
+				continue;
+
+			brate = DIV_ROUND_UP(br->bitrate, (1 << shift) * 5);
+			if (brate == rate) {
 				*rates |= BIT(j);
 				if (is_basic)
 					*basic_rates |= BIT(j);
-				if (rate < *min_rate) {
-					*min_rate = rate;
+				if ((rate * 5) < *min_rate) {
+					*min_rate = rate * 5;
 					*min_rate_index = j;
 				}
 				break;
@@ -3884,27 +3884,40 @@ static int ieee80211_prep_connection(struct ieee80211_sub_if_data *sdata,
 		if (!new_sta)
 			return -ENOMEM;
 	}
-
 	if (new_sta) {
 		u32 rates = 0, basic_rates = 0;
 		bool have_higher_than_11mbit;
 		int min_rate = INT_MAX, min_rate_index = -1;
+		struct ieee80211_chanctx_conf *chanctx_conf;
 		struct ieee80211_supported_band *sband;
 		const struct cfg80211_bss_ies *ies;
+		int shift;
+		u32 rate_flags;
 
 		sband = local->hw.wiphy->bands[cbss->channel->band];
 
 		err = ieee80211_prep_channel(sdata, cbss);
 		if (err) {
 			sta_info_free(local, new_sta);
-			return err;
+			return -EINVAL;
 		}
+		shift = ieee80211_vif_get_shift(&sdata->vif);
+
+		rcu_read_lock();
+		chanctx_conf = rcu_dereference(sdata->vif.chanctx_conf);
+		if (WARN_ON(!chanctx_conf)) {
+			rcu_read_unlock();
+			return -EINVAL;
+		}
+		rate_flags = ieee80211_chandef_rate_flags(&chanctx_conf->def);
+		rcu_read_unlock();
 
 		ieee80211_get_rates(sband, bss->supp_rates,
 				    bss->supp_rates_len,
 				    &rates, &basic_rates,
 				    &have_higher_than_11mbit,
-				    &min_rate, &min_rate_index);
+				    &min_rate, &min_rate_index,
+				    shift, rate_flags);
 
 		/*
 		 * This used to be a workaround for basic rates missing