mac80211: dynamically enable the TWT requester support on STA interfaces

Turn TWT for STA interfaces when they associate and/or receive a
beacon where the twt_responder bit has changed.
Signed-off-by: Shashidhar Lakkavalli <slakkavalli@datto.com>
Signed-off-by: John Crispin <john@phrozen.org>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>

include/net/mac80211.h

@@ -317,6 +317,7 @@ struct ieee80211_vif_chanctx_switch {
  * @BSS_CHANGED_MCAST_RATE: Multicast Rate setting changed for this interface
  * @BSS_CHANGED_FTM_RESPONDER: fime timing reasurement request responder
  *	functionality changed for this BSS (AP mode).
+ * @BSS_CHANGED_TWT: TWT status changed
  *
  */
 enum ieee80211_bss_change {
@@ -347,6 +348,7 @@ enum ieee80211_bss_change {
 	BSS_CHANGED_KEEP_ALIVE		= 1<<24,
 	BSS_CHANGED_MCAST_RATE		= 1<<25,
 	BSS_CHANGED_FTM_RESPONDER	= 1<<26,
+	BSS_CHANGED_TWT			= 1<<27,
 
 	/* when adding here, make sure to change ieee80211_reconfig */
 };

net/mac80211/mlme.c

@@ -3148,6 +3148,19 @@ static bool ieee80211_twt_req_supported(const struct sta_info *sta,
 		IEEE80211_HE_MAC_CAP0_TWT_RES;
 }
 
+static int ieee80211_recalc_twt_req(struct ieee80211_sub_if_data *sdata,
+				    struct sta_info *sta,
+				    struct ieee802_11_elems *elems)
+{
+	bool twt = ieee80211_twt_req_supported(sta, elems);
+
+	if (sdata->vif.bss_conf.twt_requester != twt) {
+		sdata->vif.bss_conf.twt_requester = twt;
+		return BSS_CHANGED_TWT;
+	}
+	return 0;
+}
+
 static bool ieee80211_assoc_success(struct ieee80211_sub_if_data *sdata,
 				    struct cfg80211_bss *cbss,
 				    struct ieee80211_mgmt *mgmt, size_t len)
@@ -3330,8 +3343,7 @@ static bool ieee80211_assoc_success(struct ieee80211_sub_if_data *sdata,
 						  sta);
 
 		bss_conf->he_support = sta->sta.he_cap.has_he;
-		bss_conf->twt_requester =
-			ieee80211_twt_req_supported(sta, &elems);
+		changed |= ieee80211_recalc_twt_req(sdata, sta, &elems);
 	} else {
 		bss_conf->he_support = false;
 		bss_conf->twt_requester = false;
@@ -3991,6 +4003,8 @@ static void ieee80211_rx_mgmt_beacon(struct ieee80211_sub_if_data *sdata,
 	mutex_lock(&local->sta_mtx);
 	sta = sta_info_get(sdata, bssid);
 
+	changed |= ieee80211_recalc_twt_req(sdata, sta, &elems);
+
 	if (ieee80211_config_bw(sdata, sta,
 				elems.ht_cap_elem, elems.ht_operation,
 				elems.vht_operation, elems.he_operation,