scan: add hidden networks into periodic scan

In addition, the periodic scan can now alternate between the
active or passive modes. The active mode is enabled by existence of
the known hidden networks and observation of them in the
previous scan result.

src/scan.c

@@ -40,6 +40,7 @@
 #include "src/ie.h"
 #include "src/common.h"
 #include "src/network.h"
+#include "src/util.h"
 #include "src/scan.h"
 
 #define SCAN_MAX_INTERVAL 320
@@ -60,6 +61,9 @@ struct scan_periodic {
 	bool rearm:1;
 	bool retry:1;
 	bool triggered:1;
+	bool needs_active_scan:1;
+	bool passive:1; /* Active or Passive scan? */
+	struct l_queue *cmds;
 };
 
 struct scan_request {
@@ -155,6 +159,8 @@ static void scan_context_free(struct scan_context *sc)
 {
 	l_debug("sc: %p", sc);
 
+	l_queue_destroy(sc->sp.cmds, (l_queue_destroy_func_t) l_genl_msg_unref);
+
 	l_queue_destroy(sc->requests, scan_request_free);
 
 	if (sc->sp.timeout)
@@ -584,8 +590,9 @@ static void scan_periodic_triggered(struct l_genl_msg *msg, void *user_data)
 		return;
 	}
 
-	sc->state = SCAN_STATE_PASSIVE;
+	sc->state = sc->sp.passive ? SCAN_STATE_PASSIVE : SCAN_STATE_ACTIVE;
-	l_debug("Periodic scan triggered for ifindex: %u", sc->ifindex);
+	l_debug("Periodic %s scan triggered for ifindex: %u", sc->sp.passive ?
+				"passive" : "active", sc->ifindex);
 
 	sc->sp.triggered = true;
 
@@ -595,16 +602,27 @@ static void scan_periodic_triggered(struct l_genl_msg *msg, void *user_data)
 
 static bool scan_periodic_send_start(struct scan_context *sc)
 {
+	struct l_genl_msg *cmd;
 	struct scan_parameters params = {};
-	struct l_genl_msg *msg;
 
-	msg = scan_build_cmd(sc, true, &params);
+	if (sc->sp.needs_active_scan && network_info_has_hidden()) {
-	if (!msg)
+		sc->sp.needs_active_scan = false;
+		sc->sp.passive = false;
+
+		params.randomize_mac_addr_hint = true;
+	} else {
+		sc->sp.passive = true;
+	}
+
+	scan_cmds_add(sc->sp.cmds, sc, sc->sp.passive, &params);
+
+	cmd = l_queue_pop_head(sc->sp.cmds);
+	if (!cmd)
 		return false;
 
-	sc->start_cmd_id = scan_send_start(&msg, scan_periodic_triggered, sc);
+	sc->start_cmd_id = scan_send_start(&cmd, scan_periodic_triggered, sc);
 	if (!sc->start_cmd_id) {
-		l_genl_msg_unref(msg);
+		l_genl_msg_unref(cmd);
 		return false;
 	}
 
@@ -635,6 +653,7 @@ void scan_periodic_start(uint32_t ifindex, scan_trigger_func_t trigger,
 	sc->sp.userdata = userdata;
 	sc->sp.retry = true;
 	sc->sp.rearm = false;
+	sc->sp.cmds = l_queue_new();
 
 	start_next_scan_request(sc);
 }
@@ -665,6 +684,10 @@ bool scan_periodic_stop(uint32_t ifindex)
 	sc->sp.userdata = NULL;
 	sc->sp.rearm = false;
 	sc->sp.retry = false;
+	sc->sp.needs_active_scan = false;
+
+	l_queue_destroy(sc->sp.cmds, (l_queue_destroy_func_t) l_genl_msg_unref);
+	sc->sp.cmds = NULL;
 
 	return true;
 }
@@ -1063,6 +1086,22 @@ static void get_scan_callback(struct l_genl_msg *msg, void *user_data)
 	l_queue_insert(results->bss_list, bss, scan_bss_rank_compare, NULL);
 }
 
+static void discover_hidden_network_bsses(struct scan_context *sc,
+						struct l_queue *bss_list)
+{
+	const struct l_queue_entry *bss_entry;
+
+	for (bss_entry = l_queue_get_entries(bss_list); bss_entry;
+						bss_entry = bss_entry->next) {
+		struct scan_bss *bss = bss_entry->data;
+
+		if (!util_ssid_is_hidden(bss->ssid_len, bss->ssid))
+			continue;
+
+		sc->sp.needs_active_scan = true;
+	}
+}
+
 static void scan_finished(struct scan_context *sc, uint32_t wiphy,
 				int err, struct l_queue *bss_list)
 {
@@ -1080,7 +1119,7 @@ static void scan_finished(struct scan_context *sc, uint32_t wiphy,
 
 		scan_request_free(sr);
 		l_queue_pop_head(sc->requests);
-	} else if (sc->state == SCAN_STATE_PASSIVE && sc->sp.interval != 0) {
+	} else if (sc->sp.interval) {
 		/*
 		 * If we'd called sc.sp->trigger, we must call back now
 		 * independent of whether the scan was succesful or was
@@ -1094,6 +1133,9 @@ static void scan_finished(struct scan_context *sc, uint32_t wiphy,
 		}
 
 		sc->sp.triggered = false;
+
+		if (bss_list)
+			discover_hidden_network_bsses(sc, bss_list);
 	}
 
 	if (callback)
@@ -1183,6 +1225,23 @@ static bool scan_send_next_cmd(struct scan_context *sc)
 		 * processing.
 		 */
 		return true;
+	} else if (sc->sp.triggered) {
+		struct l_genl_msg *cmd = l_queue_pop_head(sc->sp.cmds);
+		if (!cmd)
+			return false;
+
+		sc->sp.triggered = false;
+
+		sc->start_cmd_id = scan_send_start(&cmd,
+						scan_periodic_triggered, sc);
+
+		if (!sc->start_cmd_id) {
+			l_genl_msg_unref(cmd);
+			l_queue_clear(sc->sp.cmds,
+				(l_queue_destroy_func_t) l_genl_msg_unref);
+		}
+
+		return true;
 	}
 
 	return false;