network: Introduce a concept of known frequencies

Each known network (previously connected) will have a set
of known frequencies associated with it, e.g. a set of
frequencies from all BSSs observed. The list of known
frequencies is sorted with the most recently observed
frequency in the head.

src/knownnetworks.h

@@ -2,7 +2,7 @@
  *
  *  Wireless daemon for Linux
  *
- *  Copyright (C) 2016  Intel Corporation. All rights reserved.
+ *  Copyright (C) 2016-2019  Intel Corporation. All rights reserved.
  *
  *  This library is free software; you can redistribute it and/or
  *  modify it under the terms of the GNU Lesser General Public
@@ -26,6 +26,10 @@ struct network_info;
 typedef bool (*known_networks_foreach_func_t)(const struct network_info *info,
 						void *user_data);
 
+struct known_frequency {
+	uint32_t frequency;
+};
+
 bool known_networks_foreach(known_networks_foreach_func_t function,
 				void *user_data);
 bool known_networks_has_hidden(void);

src/network.c

@@ -259,6 +259,8 @@ void network_info_free(void *data)
 {
 	struct network_info *network = data;
 
+	l_queue_destroy(network->known_frequencies, l_free);
+
 	l_free(network);
 }
 
@@ -629,10 +631,35 @@ void network_connect_failed(struct network *network)
 	l_queue_clear(network->blacklist, NULL);
 }
 
+static bool known_frequency_match(const void *a, const void *b)
+{
+	const struct known_frequency *known_freq = a;
+	const uint32_t *frequency = b;
+
+	return known_freq->frequency == *frequency;
+}
+
 bool network_bss_add(struct network *network, struct scan_bss *bss)
 {
-	return l_queue_insert(network->bss_list, bss,
-					scan_bss_rank_compare, NULL);
+	struct known_frequency *known_freq;
+
+	if (!l_queue_insert(network->bss_list, bss, scan_bss_rank_compare,
+									NULL))
+		return false;
+
+	if (!network->info->known_frequencies)
+		network->info->known_frequencies = l_queue_new();
+
+	known_freq = l_queue_remove_if(network->info->known_frequencies,
+					known_frequency_match, &bss->frequency);
+	if (!known_freq) {
+		known_freq = l_new(struct known_frequency, 1);
+		known_freq->frequency = bss->frequency;
+	}
+
+	l_queue_push_head(network->info->known_frequencies, known_freq);
+
+	return true;
 }
 
 bool network_bss_list_isempty(struct network *network)

src/network.h

@@ -73,6 +73,7 @@ void network_blacklist_add(struct network *network, struct scan_bss *bss);
 struct network_info {
 	char ssid[33];
 	enum security type;
+	struct l_queue *known_frequencies;
 	struct timespec connected_time;	/* Time last connected */
 	int seen_count;			/* Ref count for network.info */
 	bool is_hidden:1;