wifi: mac80211: handle TPE element during CSA

Handle the transmit power envelope (TPE) element during
channel switch, applying it when the channel switch is
done.

Reviewed-by: Miriam Rachel Korenblit <[email protected]>
Link: https://msgid.link/20240506215543.486c33157d18.Idf971ad801b6961c177bdf42cc323fd1a4ca8165@changeid
Signed-off-by: Johannes Berg <[email protected]>

Author: jmberg-intel

net/mac80211/ieee80211_i.h

@@ -977,6 +977,8 @@ struct ieee80211_link_data_managed {
 
 	struct {
 		struct wiphy_delayed_work switch_work;
+		struct cfg80211_chan_def ap_chandef;
+		struct ieee80211_parsed_tpe tpe;
 		unsigned long time;
 		bool waiting_bcn;
 		bool ignored_same_chan;
@@ -1754,6 +1756,7 @@ struct ieee802_11_elems {
 
 	/* not the order in the psd values is per element, not per chandef */
 	struct ieee80211_parsed_tpe tpe;
+	struct ieee80211_parsed_tpe csa_tpe;
 
 	/* length of them, respectively */
 	u8 ext_capab_len;

net/mac80211/mlme.c

@@ -2129,6 +2129,20 @@ static void ieee80211_csa_switch_work(struct wiphy *wiphy,
 
 	link->u.mgd.csa.waiting_bcn = true;
 
+	/* apply new TPE restrictions immediately on the new channel */
+	if (link->u.mgd.csa.ap_chandef.chan->band == NL80211_BAND_6GHZ &&
+	    link->u.mgd.conn.mode >= IEEE80211_CONN_MODE_HE) {
+		ieee80211_rearrange_tpe(&link->u.mgd.csa.tpe,
+					&link->u.mgd.csa.ap_chandef,
+					&link->conf->chanreq.oper);
+		if (memcmp(&link->conf->tpe, &link->u.mgd.csa.tpe,
+			   sizeof(link->u.mgd.csa.tpe))) {
+			link->conf->tpe = link->u.mgd.csa.tpe;
+			ieee80211_link_info_change_notify(sdata, link,
+							  BSS_CHANGED_TPE);
+		}
+	}
+
 	ieee80211_sta_reset_beacon_monitor(sdata);
 	ieee80211_sta_reset_conn_monitor(sdata);
 }
@@ -2379,6 +2393,8 @@ ieee80211_sta_process_chanswitch(struct ieee80211_link_data *link,
 			ch_switch.count = csa_ie.count;
 			ch_switch.delay = csa_ie.max_switch_time;
 		}
+
+		link->u.mgd.csa.tpe = csa_elems->csa_tpe;
 	} else {
 		/*
 		 * If there was no per-STA profile for this link, we
@@ -2517,6 +2533,8 @@ ieee80211_sta_process_chanswitch(struct ieee80211_link_data *link,
 		goto drop_connection;
 	}
 
+	link->u.mgd.csa.ap_chandef = csa_ie.chanreq.ap;
+
 	link->csa.chanreq = csa_ie.chanreq;
 	if (link->u.mgd.conn.mode < IEEE80211_CONN_MODE_EHT ||
 	    sdata->vif.driver_flags & IEEE80211_VIF_IGNORE_OFDMA_WIDER_BW)

net/mac80211/parse.c

@@ -607,6 +607,13 @@ _ieee802_11_parse_elems_full(struct ieee80211_elems_parse_params *params,
 					elem_parse_failed =
 						IEEE80211_PARSE_ERR_BAD_ELEM_SIZE;
 			}
+
+			subelem = cfg80211_find_ext_elem(WLAN_EID_TX_POWER_ENVELOPE,
+							 pos, elen);
+			if (subelem)
+				ieee80211_parse_tpe(&elems->csa_tpe,
+						    subelem->data + 1,
+						    subelem->datalen - 1);
 			break;
 		case WLAN_EID_COUNTRY:
 			elems->country_elem = pos;
@@ -962,6 +969,7 @@ ieee802_11_parse_elems_full(struct ieee80211_elems_parse_params *params)
 
 	/* set all TPE entries to unlimited (but invalid) */
 	ieee80211_clear_tpe(&elems->tpe);
+	ieee80211_clear_tpe(&elems->csa_tpe);
 
 	nontransmitted_profile = elems_parse->scratch_pos;
 	nontransmitted_profile_len =