nl80211: Handle CH_SWITCH event

Some drivers may independently decide to switch channels. Handle this by
updating the hostapd and wpa_supplicant AP and GO configuration.

Signed-hostap: Thomas Pedersen <c_tpeder@qca.qualcomm.com>

src/ap/drv_callbacks.c

@@ -26,6 +26,7 @@
 #include "wps_hostapd.h"
 #include "ap_drv_ops.h"
 #include "ap_config.h"
+#include "hw_features.h"
 
 
 int hostapd_notif_assoc(struct hostapd_data *hapd, const u8 *addr,
@@ -273,6 +274,31 @@ void hostapd_event_sta_low_ack(struct hostapd_data *hapd, const u8 *addr)
 }
 
 
+void hostapd_event_ch_switch(struct hostapd_data *hapd, int freq, int ht,
+			     int offset)
+{
+	int channel;
+
+	hostapd_logger(hapd, NULL, HOSTAPD_MODULE_IEEE80211,
+		       HOSTAPD_LEVEL_INFO, "driver had channel switch: "
+		       "freq=%d, ht=%d, offset=%d", freq, ht, offset);
+
+	hapd->iface->freq = freq;
+
+	channel = hostapd_hw_get_channel(hapd, freq);
+	if (!channel) {
+		hostapd_logger(hapd, NULL, HOSTAPD_MODULE_IEEE80211,
+			       HOSTAPD_LEVEL_WARNING, "driver switched to "
+			       "bad channel!");
+		return;
+	}
+
+	hapd->iconf->channel = channel;
+	hapd->iconf->ieee80211n = ht;
+	hapd->iconf->secondary_channel = offset;
+}
+
+
 int hostapd_probe_req_rx(struct hostapd_data *hapd, const u8 *sa, const u8 *da,
 			 const u8 *bssid, const u8 *ie, size_t ie_len,
 			 int ssi_signal)
@@ -590,6 +616,13 @@ void wpa_supplicant_event(void *ctx, enum wpa_event_type event,
 		hostapd_rx_action(hapd, &data->rx_action);
 		break;
 #endif /* NEED_AP_MLME */
+	case EVENT_CH_SWITCH:
+		if (!data)
+			break;
+		hostapd_event_ch_switch(hapd, data->ch_switch.freq,
+					data->ch_switch.ht_enabled,
+					data->ch_switch.ch_offset);
+		break;
 	default:
 		wpa_printf(MSG_DEBUG, "Unknown event %d", event);
 		break;

src/ap/hostapd.h

@@ -283,5 +283,7 @@ void hostapd_event_sta_low_ack(struct hostapd_data *hapd, const u8 *addr);
 int hostapd_probe_req_rx(struct hostapd_data *hapd, const u8 *sa, const u8 *da,
 			 const u8 *bssid, const u8 *ie, size_t ie_len,
 			 int ssi_signal);
+void hostapd_event_ch_switch(struct hostapd_data *hapd, int freq, int ht,
+			     int offset);
 
 #endif /* HOSTAPD_H */

src/drivers/driver.h

@@ -2978,7 +2978,14 @@ enum wpa_event_type {
 	/**
 	 * EVENT_EAPOL_TX_STATUS - notify of EAPOL TX status
 	 */
-	EVENT_EAPOL_TX_STATUS
+	EVENT_EAPOL_TX_STATUS,
+
+	/**
+	 * EVENT_CH_SWITCH - AP or GO decided to switch channels
+	 *
+	 * Described in wpa_event_data.ch_switch
+	 * */
+	EVENT_CH_SWITCH
 };
 
 
@@ -3573,6 +3580,18 @@ union wpa_event_data {
 		int data_len;
 		int ack;
 	} eapol_tx_status;
+
+	/**
+	 * struct ch_switch
+	 * @freq: Frequency of new channel in MHz
+	 * @ht_enabled: Whether this is an HT channel
+	 * @ch_offset: Secondary channel offset
+	 */
+	struct ch_switch {
+		int freq;
+		int ht_enabled;
+		int ch_offset;
+	} ch_switch;
 };
 
 /**

src/drivers/driver_common.c

@@ -77,6 +77,7 @@ const char * event_to_string(enum wpa_event_type event)
 	E2S(SCHED_SCAN_STOPPED);
 	E2S(DRIVER_CLIENT_POLL_OK);
 	E2S(EAPOL_TX_STATUS);
+	E2S(CH_SWITCH);
 	}
 
 	return "UNKNOWN";

src/drivers/driver_nl80211.c

@@ -1196,6 +1196,40 @@ static void mlme_event_disconnect(struct wpa_driver_nl80211_data *drv,
 }
 
 
+static void mlme_event_ch_switch(struct wpa_driver_nl80211_data *drv,
+				 struct nlattr *freq, struct nlattr *type)
+{
+	union wpa_event_data data;
+	int ht_enabled = 1;
+	int chan_offset = 0;
+
+	wpa_printf(MSG_DEBUG, "nl80211: Channel switch event");
+
+	if (!freq || !type)
+		return;
+
+	switch (nla_get_u32(type)) {
+	case NL80211_CHAN_NO_HT:
+		ht_enabled = 0;
+		break;
+	case NL80211_CHAN_HT20:
+		break;
+	case NL80211_CHAN_HT40PLUS:
+		chan_offset = 1;
+		break;
+	case NL80211_CHAN_HT40MINUS:
+		chan_offset = -1;
+		break;
+	}
+
+	data.ch_switch.freq = nla_get_u32(freq);
+	data.ch_switch.ht_enabled = ht_enabled;
+	data.ch_switch.ch_offset = chan_offset;
+
+	wpa_supplicant_event(drv->ctx, EVENT_CH_SWITCH, &data);
+}
+
+
 static void mlme_timeout_event(struct wpa_driver_nl80211_data *drv,
 			       enum nl80211_commands cmd, struct nlattr *addr)
 {
@@ -2116,6 +2150,10 @@ static void do_process_drv_event(struct wpa_driver_nl80211_data *drv,
 				   tb[NL80211_ATTR_REQ_IE],
 				   tb[NL80211_ATTR_RESP_IE]);
 		break;
+	case NL80211_CMD_CH_SWITCH_NOTIFY:
+		mlme_event_ch_switch(drv, tb[NL80211_ATTR_WIPHY_FREQ],
+				     tb[NL80211_ATTR_WIPHY_CHANNEL_TYPE]);
+		break;
 	case NL80211_CMD_DISCONNECT:
 		mlme_event_disconnect(drv, tb[NL80211_ATTR_REASON_CODE],
 				      tb[NL80211_ATTR_MAC],

wpa_supplicant/ap.c

@@ -957,6 +957,17 @@ int wpa_supplicant_ap_update_beacon(struct wpa_supplicant *wpa_s)
 }
 
 
+void wpas_ap_ch_switch(struct wpa_supplicant *wpa_s, int freq, int ht,
+		       int offset)
+{
+	if (!wpa_s->ap_iface)
+		return;
+
+	wpa_s->assoc_freq = freq;
+	hostapd_event_ch_switch(wpa_s->ap_iface->bss[0], freq, ht, offset);
+}
+
+
 int wpa_supplicant_ap_mac_addr_filter(struct wpa_supplicant *wpa_s,
 				      const u8 *addr)
 {

wpa_supplicant/ap.h

@@ -49,5 +49,7 @@ int wpa_supplicant_ap_update_beacon(struct wpa_supplicant *wpa_s);
 int wpa_supplicant_ap_mac_addr_filter(struct wpa_supplicant *wpa_s,
 				      const u8 *addr);
 void wpa_supplicant_ap_pwd_auth_fail(struct wpa_supplicant *wpa_s);
+void wpas_ap_ch_switch(struct wpa_supplicant *wpa_s, int freq, int ht,
+		       int offset);
 
 #endif /* AP_H */

wpa_supplicant/events.c

@@ -2407,6 +2407,21 @@ void wpa_supplicant_event(void *ctx, enum wpa_event_type event,
 		ap_rx_from_unknown_sta(wpa_s, data->rx_from_unknown.addr,
 				       data->rx_from_unknown.wds);
 		break;
+	case EVENT_CH_SWITCH:
+		if (!data)
+			break;
+		if (!wpa_s->ap_iface) {
+			wpa_dbg(wpa_s, MSG_DEBUG, "AP: Ignore channel switch "
+				"event in non-AP mode");
+			break;
+		}
+
+#ifdef CONFIG_AP
+		wpas_ap_ch_switch(wpa_s, data->ch_switch.freq,
+				  data->ch_switch.ht_enabled,
+				  data->ch_switch.ch_offset);
+#endif /* CONFIG_AP */
+		break;
 	case EVENT_RX_MGMT: {
 		u16 fc, stype;
 		const struct ieee80211_mgmt *mgmt;