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, 62 insertions, 19 deletions

diff --git a/net/mac80211/ibss.c b/net/mac80211/ibss.c
index 7f290a8562e..272a3b37615 100644
--- a/net/mac80211/ibss.c
+++ b/net/mac80211/ibss.c
@@ -43,16 +43,17 @@ static void __ieee80211_sta_join_ibss(struct ieee80211_sub_if_data *sdata,
 {
 	struct ieee80211_if_ibss *ifibss = &sdata->u.ibss;
 	struct ieee80211_local *local = sdata->local;
-	int rates, i;
+	int rates_n = 0, i, ri;
 	struct ieee80211_mgmt *mgmt;
 	u8 *pos;
 	struct ieee80211_supported_band *sband;
 	struct cfg80211_bss *bss;
-	u32 bss_change;
+	u32 bss_change, rate_flags, rates = 0, rates_added = 0;
 	u8 supp_rates[IEEE80211_MAX_SUPP_RATES];
 	struct cfg80211_chan_def chandef;
 	struct beacon_data *presp;
 	int frame_len;
+	int shift;
 
 	sdata_assert_lock(sdata);
 
@@ -99,6 +100,7 @@ static void __ieee80211_sta_join_ibss(struct ieee80211_sub_if_data *sdata,
 	memcpy(ifibss->bssid, bssid, ETH_ALEN);
 
 	sband = local->hw.wiphy->bands[chan->band];
+	shift = ieee80211_vif_get_shift(&sdata->vif);
 
 	/* Build IBSS probe response */
 	frame_len = sizeof(struct ieee80211_hdr_3addr) +
@@ -134,15 +136,29 @@ static void __ieee80211_sta_join_ibss(struct ieee80211_sub_if_data *sdata,
 	memcpy(pos, ifibss->ssid, ifibss->ssid_len);
 	pos += ifibss->ssid_len;
 
-	rates = min_t(int, 8, sband->n_bitrates);
+	rate_flags = ieee80211_chandef_rate_flags(&chandef);
+	for (i = 0; i < sband->n_bitrates; i++) {
+		if ((rate_flags & sband->bitrates[i].flags) != rate_flags)
+			continue;
+
+		rates |= BIT(i);
+		rates_n++;
+	}
+
 	*pos++ = WLAN_EID_SUPP_RATES;
-	*pos++ = rates;
-	for (i = 0; i < rates; i++) {
-		int rate = sband->bitrates[i].bitrate;
+	*pos++ = min_t(int, 8, rates_n);
+	for (ri = 0; ri < sband->n_bitrates; ri++) {
+		int rate = DIV_ROUND_UP(sband->bitrates[ri].bitrate,
+					5 * (1 << shift));
 		u8 basic = 0;
-		if (basic_rates & BIT(i))
+		if (!(rates & BIT(ri)))
+			continue;
+
+		if (basic_rates & BIT(ri))
 			basic = 0x80;
-		*pos++ = basic | (u8) (rate / 5);
+		*pos++ = basic | (u8) rate;
+		if (++rates_added == 8)
+			break;
 	}
 
 	if (sband->band == IEEE80211_BAND_2GHZ) {
@@ -157,15 +173,20 @@ static void __ieee80211_sta_join_ibss(struct ieee80211_sub_if_data *sdata,
 	*pos++ = 0;
 	*pos++ = 0;
 
-	if (sband->n_bitrates > 8) {
+	/* put the remaining rates in WLAN_EID_EXT_SUPP_RATES */
+	if (rates_n > 8) {
 		*pos++ = WLAN_EID_EXT_SUPP_RATES;
-		*pos++ = sband->n_bitrates - 8;
-		for (i = 8; i < sband->n_bitrates; i++) {
-			int rate = sband->bitrates[i].bitrate;
+		*pos++ = rates_n - 8;
+		for (; ri < sband->n_bitrates; ri++) {
+			int rate = DIV_ROUND_UP(sband->bitrates[ri].bitrate,
+						5 * (1 << shift));
 			u8 basic = 0;
-			if (basic_rates & BIT(i))
+			if (!(rates & BIT(ri)))
+				continue;
+
+			if (basic_rates & BIT(ri))
 				basic = 0x80;
-			*pos++ = basic | (u8) (rate / 5);
+			*pos++ = basic | (u8) rate;
 		}
 	}
 
@@ -244,7 +265,7 @@ static void __ieee80211_sta_join_ibss(struct ieee80211_sub_if_data *sdata,
 	sdata->vif.bss_conf.ibss_creator = creator;
 	ieee80211_bss_info_change_notify(sdata, bss_change);
 
-	ieee80211_sta_def_wmm_params(sdata, sband->n_bitrates, supp_rates);
+	ieee80211_sta_def_wmm_params(sdata, rates, supp_rates);
 
 	ifibss->state = IEEE80211_IBSS_MLME_JOINED;
 	mod_timer(&ifibss->timer,
@@ -268,6 +289,8 @@ static void ieee80211_sta_join_ibss(struct ieee80211_sub_if_data *sdata,
 	u16 beacon_int = cbss->beacon_interval;
 	const struct cfg80211_bss_ies *ies;
 	u64 tsf;
+	u32 rate_flags;
+	int shift;
 
 	sdata_assert_lock(sdata);
 
@@ -275,15 +298,24 @@ static void ieee80211_sta_join_ibss(struct ieee80211_sub_if_data *sdata,
 		beacon_int = 10;
 
 	sband = sdata->local->hw.wiphy->bands[cbss->channel->band];
+	rate_flags = ieee80211_chandef_rate_flags(&sdata->u.ibss.chandef);
+	shift = ieee80211_vif_get_shift(&sdata->vif);
 
 	basic_rates = 0;
 
 	for (i = 0; i < bss->supp_rates_len; i++) {
-		int rate = (bss->supp_rates[i] & 0x7f) * 5;
+		int rate = bss->supp_rates[i] & 0x7f;
 		bool is_basic = !!(bss->supp_rates[i] & 0x80);
 
 		for (j = 0; j < sband->n_bitrates; j++) {
-			if (sband->bitrates[j].bitrate == rate) {
+			int brate;
+			if ((rate_flags & sband->bitrates[j].flags)
+			    != rate_flags)
+				continue;
+
+			brate = DIV_ROUND_UP(sband->bitrates[j].bitrate,
+					     5 * (1 << shift));
+			if (brate == rate) {
 				if (is_basic)
 					basic_rates |= BIT(j);
 				break;
@@ -465,7 +497,7 @@ static void ieee80211_rx_bss_info(struct ieee80211_sub_if_data *sdata,
 		sta = sta_info_get(sdata, mgmt->sa);
 
 		if (elems->supp_rates) {
-			supp_rates = ieee80211_sta_get_rates(local, elems,
+			supp_rates = ieee80211_sta_get_rates(sdata, elems,
 							     band, NULL);
 			if (sta) {
 				u32 prev_rates;
@@ -589,7 +621,7 @@ static void ieee80211_rx_bss_info(struct ieee80211_sub_if_data *sdata,
 			 "beacon TSF higher than local TSF - IBSS merge with BSSID %pM\n",
 			 mgmt->bssid);
 		ieee80211_sta_join_ibss(sdata, bss);
-		supp_rates = ieee80211_sta_get_rates(local, elems, band, NULL);
+		supp_rates = ieee80211_sta_get_rates(sdata, elems, band, NULL);
 		ieee80211_ibss_add_sta(sdata, mgmt->bssid, mgmt->sa,
 				       supp_rates);
 		rcu_read_unlock();
@@ -1024,6 +1056,9 @@ int ieee80211_ibss_join(struct ieee80211_sub_if_data *sdata,
 			struct cfg80211_ibss_params *params)
 {
 	u32 changed = 0;
+	u32 rate_flags;
+	struct ieee80211_supported_band *sband;
+	int i;
 
 	if (params->bssid) {
 		memcpy(sdata->u.ibss.bssid, params->bssid, ETH_ALEN);
@@ -1034,6 +1069,14 @@ int ieee80211_ibss_join(struct ieee80211_sub_if_data *sdata,
 	sdata->u.ibss.privacy = params->privacy;
 	sdata->u.ibss.control_port = params->control_port;
 	sdata->u.ibss.basic_rates = params->basic_rates;
+
+	/* fix basic_rates if channel does not support these rates */
+	rate_flags = ieee80211_chandef_rate_flags(&params->chandef);
+	sband = sdata->local->hw.wiphy->bands[params->chandef.chan->band];
+	for (i = 0; i < sband->n_bitrates; i++) {
+		if ((rate_flags & sband->bitrates[i].flags) != rate_flags)
+			sdata->u.ibss.basic_rates &= ~BIT(i);
+	}
 	memcpy(sdata->vif.bss_conf.mcast_rate, params->mcast_rate,
 	       sizeof(params->mcast_rate));