mac80211: upgrade BW of TDLS peers when possible

Define a station chandef, to be used for wider-bw TDLS peers. When both
peers support the feature, upgrade the channel bandwidth to the maximum
allowed by both peers and regulatory. Currently widths up to 80MHz are
supported in the 5GHz band.

When a TDLS peer connects/disconnects recalculate the channel type of the
current chanctx.
Make the chanctx width calculation consider wider-bw TDLS peers and
similarly fix the max_required_bw calculation for the chanctx min_def.
Since the sta->bandwidth is calculated only later on, take
bss_conf.chandef.width as the minimal width for station interface.

Set the upgraded channel width in the VHT-operation set during TDLS setup.

Signed-off-by: Arik Nemtsov <arikx.nemtsov@intel.com>
Signed-off-by: Emmanuel Grumbach <emmanuel.grumbach@intel.com>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>

1 files changed, 98 insertions, 7 deletions

diff --git a/net/mac80211/tdls.c b/net/mac80211/tdls.c
index fec1b336d03c..fb846cb047d6 100644
--- a/net/mac80211/tdls.c
+++ b/net/mac80211/tdls.c
@@ -292,6 +292,60 @@ static void ieee80211_tdls_add_wmm_param_ie(struct ieee80211_sub_if_data *sdata,
 }
 
 static void
+ieee80211_tdls_chandef_vht_upgrade(struct ieee80211_sub_if_data *sdata,
+				   struct sta_info *sta)
+{
+	/* IEEE802.11ac-2013 Table E-4 */
+	u16 centers_80mhz[] = { 5210, 5290, 5530, 5610, 5690, 5775 };
+	struct cfg80211_chan_def uc = sta->tdls_chandef;
+	enum nl80211_chan_width max_width = ieee80211_get_sta_bw(&sta->sta);
+	int i;
+
+	/* only support upgrading non-narrow channels up to 80Mhz */
+	if (max_width == NL80211_CHAN_WIDTH_5 ||
+	    max_width == NL80211_CHAN_WIDTH_10)
+		return;
+
+	if (max_width > NL80211_CHAN_WIDTH_80)
+		max_width = NL80211_CHAN_WIDTH_80;
+
+	if (uc.width == max_width)
+		return;
+	/*
+	 * Channel usage constrains in the IEEE802.11ac-2013 specification only
+	 * allow expanding a 20MHz channel to 80MHz in a single way. In
+	 * addition, there are no 40MHz allowed channels that are not part of
+	 * the allowed 80MHz range in the 5GHz spectrum (the relevant one here).
+	 */
+	for (i = 0; i < ARRAY_SIZE(centers_80mhz); i++)
+		if (abs(uc.chan->center_freq - centers_80mhz[i]) <= 30) {
+			uc.center_freq1 = centers_80mhz[i];
+			uc.width = NL80211_CHAN_WIDTH_80;
+			break;
+		}
+
+	if (!uc.center_freq1)
+		return;
+
+	/* proceed to downgrade the chandef until usable or the same */
+	while (uc.width > max_width &&
+	       !cfg80211_reg_can_beacon(sdata->local->hw.wiphy,
+					&uc, sdata->wdev.iftype))
+		ieee80211_chandef_downgrade(&uc);
+
+	if (!cfg80211_chandef_identical(&uc, &sta->tdls_chandef)) {
+		tdls_dbg(sdata, "TDLS ch width upgraded %d -> %d\n",
+			 sta->tdls_chandef.width, uc.width);
+
+		/*
+		 * the station is not yet authorized when BW upgrade is done,
+		 * locking is not required
+		 */
+		sta->tdls_chandef = uc;
+	}
+}
+
+static void
 ieee80211_tdls_add_setup_start_ies(struct ieee80211_sub_if_data *sdata,
 				   struct sk_buff *skb, const u8 *peer,
 				   u8 action_code, bool initiator,
@@ -358,15 +412,17 @@ ieee80211_tdls_add_setup_start_ies(struct ieee80211_sub_if_data *sdata,
 		offset = noffset;
 	}
 
-	rcu_read_lock();
+	mutex_lock(&local->sta_mtx);
 
 	/* we should have the peer STA if we're already responding */
 	if (action_code == WLAN_TDLS_SETUP_RESPONSE) {
 		sta = sta_info_get(sdata, peer);
 		if (WARN_ON_ONCE(!sta)) {
-			rcu_read_unlock();
+			mutex_unlock(&local->sta_mtx);
 			return;
 		}
+
+		sta->tdls_chandef = sdata->vif.bss_conf.chandef;
 	}
 
 	ieee80211_tdls_add_oper_classes(sdata, skb);
@@ -456,9 +512,16 @@ ieee80211_tdls_add_setup_start_ies(struct ieee80211_sub_if_data *sdata,
 
 		pos = skb_put(skb, sizeof(struct ieee80211_vht_cap) + 2);
 		ieee80211_ie_build_vht_cap(pos, &vht_cap, vht_cap.cap);
+
+		/*
+		 * if both peers support WIDER_BW, we can expand the chandef to
+		 * a wider compatible one, up to 80MHz
+		 */
+		if (test_sta_flag(sta, WLAN_STA_TDLS_WIDER_BW))
+			ieee80211_tdls_chandef_vht_upgrade(sdata, sta);
 	}
 
-	rcu_read_unlock();
+	mutex_unlock(&local->sta_mtx);
 
 	/* add any remaining IEs */
 	if (extra_ies_len) {
@@ -482,15 +545,17 @@ ieee80211_tdls_add_setup_cfm_ies(struct ieee80211_sub_if_data *sdata,
 	enum ieee80211_band band = ieee80211_get_sdata_band(sdata);
 	u8 *pos;
 
-	rcu_read_lock();
+	mutex_lock(&local->sta_mtx);
 
 	sta = sta_info_get(sdata, peer);
 	ap_sta = sta_info_get(sdata, ifmgd->bssid);
 	if (WARN_ON_ONCE(!sta || !ap_sta)) {
-		rcu_read_unlock();
+		mutex_unlock(&local->sta_mtx);
 		return;
 	}
 
+	sta->tdls_chandef = sdata->vif.bss_conf.chandef;
+
 	/* add any custom IEs that go before the QoS IE */
 	if (extra_ies_len) {
 		static const u8 before_qos[] = {
@@ -538,12 +603,19 @@ ieee80211_tdls_add_setup_cfm_ies(struct ieee80211_sub_if_data *sdata,
 
 	/* only include VHT-operation if not on the 2.4GHz band */
 	if (band != IEEE80211_BAND_2GHZ && sta->sta.vht_cap.vht_supported) {
+		/*
+		 * if both peers support WIDER_BW, we can expand the chandef to
+		 * a wider compatible one, up to 80MHz
+		 */
+		if (test_sta_flag(sta, WLAN_STA_TDLS_WIDER_BW))
+			ieee80211_tdls_chandef_vht_upgrade(sdata, sta);
+
 		pos = skb_put(skb, 2 + sizeof(struct ieee80211_vht_operation));
 		ieee80211_ie_build_vht_oper(pos, &sta->sta.vht_cap,
-					    &sdata->vif.bss_conf.chandef);
+					    &sta->tdls_chandef);
 	}
 
-	rcu_read_unlock();
+	mutex_unlock(&local->sta_mtx);
 
 	/* add any remaining IEs */
 	if (extra_ies_len) {
@@ -1154,6 +1226,22 @@ int ieee80211_tdls_mgmt(struct wiphy *wiphy, struct net_device *dev,
 	return ret;
 }
 
+static void iee80211_tdls_recalc_chanctx(struct ieee80211_sub_if_data *sdata)
+{
+	struct ieee80211_local *local = sdata->local;
+	struct ieee80211_chanctx_conf *conf;
+	struct ieee80211_chanctx *ctx;
+
+	mutex_lock(&local->chanctx_mtx);
+	conf = rcu_dereference_protected(sdata->vif.chanctx_conf,
+					 lockdep_is_held(&local->chanctx_mtx));
+	if (conf) {
+		ctx = container_of(conf, struct ieee80211_chanctx, conf);
+		ieee80211_recalc_chanctx_chantype(local, ctx);
+	}
+	mutex_unlock(&local->chanctx_mtx);
+}
+
 int ieee80211_tdls_oper(struct wiphy *wiphy, struct net_device *dev,
 			const u8 *peer, enum nl80211_tdls_operation oper)
 {
@@ -1190,6 +1278,8 @@ int ieee80211_tdls_oper(struct wiphy *wiphy, struct net_device *dev,
 			break;
 		}
 
+		iee80211_tdls_recalc_chanctx(sdata);
+
 		rcu_read_lock();
 		sta = sta_info_get(sdata, peer);
 		if (!sta) {
@@ -1221,6 +1311,7 @@ int ieee80211_tdls_oper(struct wiphy *wiphy, struct net_device *dev,
 		ieee80211_flush_queues(local, sdata, false);
 
 		ret = sta_info_destroy_addr(sdata, peer);
+		iee80211_tdls_recalc_chanctx(sdata);
 		break;
 	default:
 		ret = -ENOTSUPP;