3 * Copyright (c) 2009, Jouni Malinen <j@w1.fi>
5 * This program is free software; you can redistribute it and/or modify
6 * it under the terms of the GNU General Public License version 2 as
7 * published by the Free Software Foundation.
9 * Alternatively, this software may be distributed under the terms of BSD
12 * See README and COPYING for more details.
15 #include "utils/includes.h"
17 #include "utils/common.h"
18 #include "utils/eloop.h"
19 #include "common/ieee802_11_defs.h"
20 #include "drivers/driver.h"
21 #include "wpa_supplicant_i.h"
26 #ifndef WPA_BSS_MAX_COUNT
27 #define WPA_BSS_MAX_COUNT 200
28 #endif /* WPA_BSS_MAX_COUNT */
31 * WPA_BSS_EXPIRATION_PERIOD - Period of expiration run in seconds
33 #define WPA_BSS_EXPIRATION_PERIOD 10
36 * WPA_BSS_EXPIRATION_AGE - BSS entry age after which it can be expired
38 * This value control the time in seconds after which a BSS entry gets removed
39 * if it has not been updated or is not in use.
41 #define WPA_BSS_EXPIRATION_AGE 180
44 * WPA_BSS_EXPIRATION_SCAN_COUNT - Expire BSS after number of scans
46 * If the BSS entry has not been seen in this many scans, it will be removed.
47 * Value 1 means that the entry is removed after the first scan without the
48 * BSSID being seen. Larger values can be used to avoid BSS entries
49 * disappearing if they are not visible in every scan (e.g., low signal quality
52 #define WPA_BSS_EXPIRATION_SCAN_COUNT 2
55 static void wpa_bss_remove(struct wpa_supplicant *wpa_s, struct wpa_bss *bss)
57 dl_list_del(&bss->list);
59 wpa_printf(MSG_DEBUG, "BSS: Remove id %u BSSID " MACSTR " SSID '%s'",
60 bss->id, MAC2STR(bss->bssid),
61 wpa_ssid_txt(bss->ssid, bss->ssid_len));
62 wpas_notify_bss_removed(wpa_s, bss->bssid);
67 static struct wpa_bss * wpa_bss_get(struct wpa_supplicant *wpa_s,
68 const u8 *bssid, const u8 *ssid,
72 dl_list_for_each(bss, &wpa_s->bss, struct wpa_bss, list) {
73 if (os_memcmp(bss->bssid, bssid, ETH_ALEN) == 0 &&
74 bss->ssid_len == ssid_len &&
75 os_memcmp(bss->ssid, ssid, ssid_len) == 0)
82 static void wpa_bss_copy_res(struct wpa_bss *dst, struct wpa_scan_res *src)
86 dst->flags = src->flags;
87 os_memcpy(dst->bssid, src->bssid, ETH_ALEN);
88 dst->freq = src->freq;
89 dst->beacon_int = src->beacon_int;
90 dst->caps = src->caps;
91 dst->qual = src->qual;
92 dst->noise = src->noise;
93 dst->level = src->level;
96 os_get_time(&dst->last_update);
97 dst->last_update.sec -= src->age / 1000;
98 usec = (src->age % 1000) * 1000;
99 if (dst->last_update.usec < usec) {
100 dst->last_update.sec--;
101 dst->last_update.usec += 1000000;
103 dst->last_update.usec -= usec;
107 static void wpa_bss_add(struct wpa_supplicant *wpa_s,
108 const u8 *ssid, size_t ssid_len,
109 struct wpa_scan_res *res)
113 bss = os_zalloc(sizeof(*bss) + res->ie_len);
116 bss->id = wpa_s->bss_next_id++;
117 bss->last_update_idx = wpa_s->bss_update_idx;
118 wpa_bss_copy_res(bss, res);
119 os_memcpy(bss->ssid, ssid, ssid_len);
120 bss->ssid_len = ssid_len;
121 bss->ie_len = res->ie_len;
122 os_memcpy(bss + 1, res + 1, res->ie_len);
124 dl_list_add_tail(&wpa_s->bss, &bss->list);
126 wpa_printf(MSG_DEBUG, "BSS: Add new id %u BSSID " MACSTR " SSID '%s'",
127 bss->id, MAC2STR(bss->bssid), wpa_ssid_txt(ssid, ssid_len));
128 wpas_notify_bss_added(wpa_s, res->bssid);
129 if (wpa_s->num_bss > WPA_BSS_MAX_COUNT) {
130 /* Remove the oldest entry */
131 wpa_bss_remove(wpa_s, dl_list_first(&wpa_s->bss,
132 struct wpa_bss, list));
137 static void wpa_bss_update(struct wpa_supplicant *wpa_s, struct wpa_bss *bss,
138 struct wpa_scan_res *res)
140 bss->scan_miss_count = 0;
141 bss->last_update_idx = wpa_s->bss_update_idx;
142 wpa_bss_copy_res(bss, res);
143 /* Move the entry to the end of the list */
144 dl_list_del(&bss->list);
145 if (bss->ie_len >= res->ie_len) {
146 os_memcpy(bss + 1, res + 1, res->ie_len);
147 bss->ie_len = res->ie_len;
149 struct wpa_bss *nbss;
150 nbss = os_realloc(bss, sizeof(*bss) + res->ie_len);
153 os_memcpy(bss + 1, res + 1, res->ie_len);
154 bss->ie_len = res->ie_len;
157 dl_list_add_tail(&wpa_s->bss, &bss->list);
161 void wpa_bss_update_start(struct wpa_supplicant *wpa_s)
163 wpa_s->bss_update_idx++;
164 wpa_printf(MSG_DEBUG, "BSS: Start scan result update %u",
165 wpa_s->bss_update_idx);
169 void wpa_bss_update_scan_res(struct wpa_supplicant *wpa_s,
170 struct wpa_scan_res *res)
175 ssid = wpa_scan_get_ie(res, WLAN_EID_SSID);
177 wpa_printf(MSG_DEBUG, "BSS: No SSID IE included for " MACSTR,
178 MAC2STR(res->bssid));
182 wpa_printf(MSG_DEBUG, "BSS: Too long SSID IE included for "
183 MACSTR, MAC2STR(res->bssid));
187 /* TODO: add option for ignoring BSSes we are not interested in
188 * (to save memory) */
189 bss = wpa_bss_get(wpa_s, res->bssid, ssid + 2, ssid[1]);
191 wpa_bss_add(wpa_s, ssid + 2, ssid[1], res);
193 wpa_bss_update(wpa_s, bss, res);
197 void wpa_bss_update_end(struct wpa_supplicant *wpa_s)
199 struct wpa_bss *bss, *n;
201 /* TODO: expire only entries that were on the scanned frequencies/SSIDs
202 * list; need to get info from driver about scanned frequencies and
203 * SSIDs to be able to figure out which entries should be expired based
206 dl_list_for_each_safe(bss, n, &wpa_s->bss, struct wpa_bss, list) {
207 if (bss->last_update_idx < wpa_s->bss_update_idx)
208 bss->scan_miss_count++;
209 if (bss->scan_miss_count >= WPA_BSS_EXPIRATION_SCAN_COUNT) {
210 wpa_printf(MSG_DEBUG, "BSS: Expire BSS %u due to no "
211 "match in scan", bss->id);
212 wpa_bss_remove(wpa_s, bss);
218 static void wpa_bss_timeout(void *eloop_ctx, void *timeout_ctx)
220 struct wpa_supplicant *wpa_s = eloop_ctx;
221 struct wpa_bss *bss, *n;
224 if (dl_list_empty(&wpa_s->bss))
228 t.sec -= WPA_BSS_EXPIRATION_AGE;
230 dl_list_for_each_safe(bss, n, &wpa_s->bss, struct wpa_bss, list) {
231 if (os_memcmp(bss->bssid, wpa_s->bssid, ETH_ALEN) == 0 ||
232 os_memcmp(bss->bssid, wpa_s->pending_bssid, ETH_ALEN) == 0)
233 continue; /* do not expire BSSes that are in use */
235 if (os_time_before(&bss->last_update, &t)) {
236 wpa_printf(MSG_DEBUG, "BSS: Expire BSS %u due to age",
238 wpa_bss_remove(wpa_s, bss);
242 eloop_register_timeout(WPA_BSS_EXPIRATION_PERIOD, 0,
243 wpa_bss_timeout, wpa_s, NULL);
247 int wpa_bss_init(struct wpa_supplicant *wpa_s)
249 dl_list_init(&wpa_s->bss);
250 eloop_register_timeout(WPA_BSS_EXPIRATION_PERIOD, 0,
251 wpa_bss_timeout, wpa_s, NULL);
256 void wpa_bss_deinit(struct wpa_supplicant *wpa_s)
258 struct wpa_bss *bss, *n;
259 eloop_cancel_timeout(wpa_bss_timeout, wpa_s, NULL);
260 dl_list_for_each_safe(bss, n, &wpa_s->bss, struct wpa_bss, list)
261 wpa_bss_remove(wpa_s, bss);