Continue scanning if sched_scan stops unexpectedly

When scheduled scan stops without the interface request (for example,
driver stopped it unexpectedly), start a regular scan to continue
scanning for networks and avoid being left with no scan at all.

Signed-off-by: Avraham Stern <avraham.stern@intel.com>

wpa_supplicant/events.c

@@ -4065,6 +4065,20 @@ void wpa_supplicant_event(void *ctx, enum wpa_event_type event,
 		if (wpa_s->wpa_state == WPA_INTERFACE_DISABLED)
 			break;
 
+		/*
+		 * If the driver stopped scanning without being requested to,
+		 * request a new scan to continue scanning for networks.
+		 */
+		if (!wpa_s->sched_scan_stop_req &&
+		    wpa_s->wpa_state == WPA_SCANNING) {
+			wpa_dbg(wpa_s, MSG_DEBUG,
+				"Restart scanning after unexpected sched_scan stop event");
+			wpa_supplicant_req_scan(wpa_s, 1, 0);
+			break;
+		}
+
+		wpa_s->sched_scan_stop_req = 0;
+
 		/*
 		 * Start a new sched scan to continue searching for more SSIDs
 		 * either if timed out or PNO schedule scan is pending.

wpa_supplicant/scan.c

@@ -1256,6 +1256,8 @@ int wpa_supplicant_req_sched_scan(struct wpa_supplicant *wpa_s)
 	if (max_sched_scan_ssids < 1 || wpa_s->conf->disable_scan_offload)
 		return -1;
 
+	wpa_s->sched_scan_stop_req = 0;
+
 	if (wpa_s->sched_scanning) {
 		wpa_dbg(wpa_s, MSG_DEBUG, "Already sched scanning");
 		return 0;
@@ -1554,6 +1556,9 @@ void wpa_supplicant_cancel_sched_scan(struct wpa_supplicant *wpa_s)
 	if (!wpa_s->sched_scanning)
 		return;
 
+	if (wpa_s->sched_scanning)
+		wpa_s->sched_scan_stop_req = 1;
+
 	wpa_dbg(wpa_s, MSG_DEBUG, "Cancelling sched scan");
 	eloop_cancel_timeout(wpa_supplicant_sched_scan_timeout, wpa_s, NULL);
 	wpa_supplicant_stop_sched_scan(wpa_s);
@@ -2530,6 +2535,7 @@ int wpas_stop_pno(struct wpa_supplicant *wpa_s)
 		return 0;
 
 	ret = wpa_supplicant_stop_sched_scan(wpa_s);
+	wpa_s->sched_scan_stop_req = 1;
 
 	wpa_s->pno = 0;
 	wpa_s->pno_sched_pending = 0;

wpa_supplicant/wpa_supplicant_i.h

@@ -574,6 +574,7 @@ struct wpa_supplicant {
 	struct wpa_radio_work *scan_work;
 	int scanning;
 	int sched_scanning;
+	unsigned int sched_scan_stop_req:1;
 	int new_connection;
 
 	int eapol_received; /* number of EAPOL packets received after the