Add filter support to scheduled scans

Pass SSIDs to be matched in scheduled scan results. Only the SSIDs
that are included in the match lists will be reported by the driver,
so the filtering can be offloaded to the hardware and the power
consumption can be reduced.

Signed-off-by: Luciano Coelho <coelho@ti.com>

src/drivers/driver.h

@@ -696,6 +696,7 @@ struct wpa_driver_capa {
 	int max_scan_ssids;
 	int max_sched_scan_ssids;
 	int sched_scan_supported;
+	int max_match_sets;
 
 	/**
 	 * max_remain_on_chan - Maximum remain-on-channel duration in msec

wpa_supplicant/scan.c

@@ -628,7 +628,6 @@ int wpa_supplicant_req_sched_scan(struct wpa_supplicant *wpa_s)
 	struct wpa_ssid *ssid;
 	struct wpabuf *wps_ie = NULL;
 	int ret;
-	int use_wildcard = 0;
 	unsigned int max_sched_scan_ssids;
 
 	if (!wpa_s->sched_scan_supported)
@@ -644,6 +643,10 @@ int wpa_supplicant_req_sched_scan(struct wpa_supplicant *wpa_s)
 
 	os_memset(&params, 0, sizeof(params));
 
+	/* If we can't allocate space for the filters, we just don't filter */
+	params.filter_ssids = os_zalloc(wpa_s->max_match_sets *
+					sizeof(struct wpa_driver_scan_filter));
+
 	prev_state = wpa_s->wpa_state;
 	if (wpa_s->wpa_state == WPA_DISCONNECTED ||
 	    wpa_s->wpa_state == WPA_INACTIVE)
@@ -678,33 +681,36 @@ int wpa_supplicant_req_sched_scan(struct wpa_supplicant *wpa_s)
 			continue;
 		}
 
-		if (!ssid->scan_ssid)
-			use_wildcard = 1;
-		else {
+		if (params.filter_ssids && ssid->ssid && ssid->ssid_len) {
+			os_memcpy(params.filter_ssids[params.num_filter_ssids].ssid,
+				  ssid->ssid, ssid->ssid_len);
+			params.filter_ssids[params.num_filter_ssids].ssid_len =
+				ssid->ssid_len;
+			params.num_filter_ssids++;
+		}
+
+		if (ssid->scan_ssid) {
 			params.ssids[params.num_ssids].ssid =
 				ssid->ssid;
 			params.ssids[params.num_ssids].ssid_len =
 				ssid->ssid_len;
 			params.num_ssids++;
-			if (params.num_ssids + 1 >= max_sched_scan_ssids) {
+			if (params.num_ssids >= max_sched_scan_ssids) {
 				wpa_s->prev_sched_ssid = ssid;
 				break;
 			}
 		}
+
+		if (params.num_filter_ssids >= wpa_s->max_match_sets)
+			break;
 		wpa_s->prev_sched_ssid = ssid;
 		ssid = ssid->next;
 	}
 
-	if (ssid || use_wildcard) {
-		wpa_dbg(wpa_s, MSG_DEBUG, "Include wildcard SSID in "
-			"the sched scan request");
-		params.num_ssids++;
-	} else {
-		wpa_dbg(wpa_s, MSG_DEBUG, "ssid %p - list ended", ssid);
-	}
-
-	if (!params.num_ssids)
+	if (!params.num_ssids) {
+		os_free(params.filter_ssids);
 		return 0;
+	}
 
 	if (wpa_s->wps)
 		wps_ie = wpa_supplicant_extra_ies(wpa_s, &params);
@@ -716,6 +722,7 @@ int wpa_supplicant_req_sched_scan(struct wpa_supplicant *wpa_s)
 	ret = wpa_supplicant_start_sched_scan(wpa_s, &params,
 					      wpa_s->sched_scan_interval);
 	wpabuf_free(wps_ie);
+	os_free(params.filter_ssids);
 	if (ret) {
 		wpa_msg(wpa_s, MSG_WARNING, "Failed to initiate sched scan");
 		if (prev_state != wpa_s->wpa_state)

wpa_supplicant/wpa_supplicant.c

@@ -2286,6 +2286,7 @@ next_driver:
 		wpa_s->max_scan_ssids = capa.max_scan_ssids;
 		wpa_s->max_sched_scan_ssids = capa.max_sched_scan_ssids;
 		wpa_s->sched_scan_supported = capa.sched_scan_supported;
+		wpa_s->max_match_sets = capa.max_match_sets;
 		wpa_s->max_remain_on_chan = capa.max_remain_on_chan;
 		wpa_s->max_stations = capa.max_stations;
 	}

wpa_supplicant/wpa_supplicant_i.h

@@ -437,6 +437,7 @@ struct wpa_supplicant {
 	int max_scan_ssids;
 	int max_sched_scan_ssids;
 	int sched_scan_supported;
+	unsigned int max_match_sets;
 	unsigned int max_remain_on_chan;
 	unsigned int max_stations;