[PATCH 07/11] wpa_s: add filter support to scheduled scans

[Luciano Coelho]

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 at ti.com>
---
 src/drivers/driver.h              |    1 +
 wpa_supplicant/scan.c             |   35 +++++++++++++++++++++--------------
 wpa_supplicant/wpa_supplicant.c   |    1 +
 wpa_supplicant/wpa_supplicant_i.h |    1 +
 4 files changed, 24 insertions(+), 14 deletions(-)

diff --git a/src/drivers/driver.h b/src/drivers/driver.h
index c0914fc..2432d59 100644
--- a/src/drivers/driver.h
+++ b/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
diff --git a/wpa_supplicant/scan.c b/wpa_supplicant/scan.c
index 151a1fa..9aa0967 100644
--- a/wpa_supplicant/scan.c
+++ b/wpa_supplicant/scan.c
@@ -587,7 +587,6 @@ int wpa_supplicant_req_sched_scan(struct wpa_supplicant *wpa_s)
 	enum wpa_states prev_state;
 	struct wpa_ssid *ssid;
 	int ret;
-	int use_wildcard = 0;
 	int max_sched_scan_ssids;
 
 	if (!wpa_s->sched_scan_supported)
@@ -605,6 +604,10 @@ 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)
@@ -639,39 +642,43 @@ 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;
+	}
 
 	wpa_dbg(wpa_s, MSG_DEBUG, "Starting sched scan: interval %d timeout %d",
 		wpa_s->sched_scan_interval, wpa_s->sched_scan_timeout);
 
 	ret = wpa_supplicant_start_sched_scan(wpa_s, &params,
 					      wpa_s->sched_scan_interval);
+	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)
diff --git a/wpa_supplicant/wpa_supplicant.c b/wpa_supplicant/wpa_supplicant.c
index 320e16c..c7c6b45 100644
--- a/wpa_supplicant/wpa_supplicant.c
+++ b/wpa_supplicant/wpa_supplicant.c
@@ -2249,6 +2249,7 @@ 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;
 	}
diff --git a/wpa_supplicant/wpa_supplicant_i.h b/wpa_supplicant/wpa_supplicant_i.h
index 2c5c805..a774941 100644
--- a/wpa_supplicant/wpa_supplicant_i.h
+++ b/wpa_supplicant/wpa_supplicant_i.h
@@ -430,6 +430,7 @@ struct wpa_supplicant {
 	int max_scan_ssids;
 	int max_sched_scan_ssids;
 	int sched_scan_supported;
+	int max_match_sets;
 	unsigned int max_remain_on_chan;
 	unsigned int max_stations;
 
-- 
1.7.1