bss.c 9.9 KB

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  1. /*
  2. * BSS table
  3. * Copyright (c) 2009-2010, Jouni Malinen <j@w1.fi>
  4. *
  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.
  8. *
  9. * Alternatively, this software may be distributed under the terms of BSD
  10. * license.
  11. *
  12. * See README and COPYING for more details.
  13. */
  14. #include "utils/includes.h"
  15. #include "utils/common.h"
  16. #include "utils/eloop.h"
  17. #include "common/ieee802_11_defs.h"
  18. #include "drivers/driver.h"
  19. #include "wpa_supplicant_i.h"
  20. #include "notify.h"
  21. #include "bss.h"
  22. #ifndef WPA_BSS_MAX_COUNT
  23. #define WPA_BSS_MAX_COUNT 200
  24. #endif /* WPA_BSS_MAX_COUNT */
  25. /**
  26. * WPA_BSS_EXPIRATION_PERIOD - Period of expiration run in seconds
  27. */
  28. #define WPA_BSS_EXPIRATION_PERIOD 10
  29. /**
  30. * WPA_BSS_EXPIRATION_AGE - BSS entry age after which it can be expired
  31. *
  32. * This value control the time in seconds after which a BSS entry gets removed
  33. * if it has not been updated or is not in use.
  34. */
  35. #define WPA_BSS_EXPIRATION_AGE 180
  36. /**
  37. * WPA_BSS_EXPIRATION_SCAN_COUNT - Expire BSS after number of scans
  38. *
  39. * If the BSS entry has not been seen in this many scans, it will be removed.
  40. * Value 1 means that the entry is removed after the first scan without the
  41. * BSSID being seen. Larger values can be used to avoid BSS entries
  42. * disappearing if they are not visible in every scan (e.g., low signal quality
  43. * or interference).
  44. */
  45. #define WPA_BSS_EXPIRATION_SCAN_COUNT 2
  46. static void wpa_bss_remove(struct wpa_supplicant *wpa_s, struct wpa_bss *bss)
  47. {
  48. dl_list_del(&bss->list);
  49. dl_list_del(&bss->list_id);
  50. wpa_s->num_bss--;
  51. wpa_printf(MSG_DEBUG, "BSS: Remove id %u BSSID " MACSTR " SSID '%s'",
  52. bss->id, MAC2STR(bss->bssid),
  53. wpa_ssid_txt(bss->ssid, bss->ssid_len));
  54. wpas_notify_bss_removed(wpa_s, bss->bssid, bss->id);
  55. os_free(bss);
  56. }
  57. struct wpa_bss * wpa_bss_get(struct wpa_supplicant *wpa_s, const u8 *bssid,
  58. const u8 *ssid, size_t ssid_len)
  59. {
  60. struct wpa_bss *bss;
  61. dl_list_for_each(bss, &wpa_s->bss, struct wpa_bss, list) {
  62. if (os_memcmp(bss->bssid, bssid, ETH_ALEN) == 0 &&
  63. bss->ssid_len == ssid_len &&
  64. os_memcmp(bss->ssid, ssid, ssid_len) == 0)
  65. return bss;
  66. }
  67. return NULL;
  68. }
  69. static void wpa_bss_copy_res(struct wpa_bss *dst, struct wpa_scan_res *src)
  70. {
  71. os_time_t usec;
  72. dst->flags = src->flags;
  73. os_memcpy(dst->bssid, src->bssid, ETH_ALEN);
  74. dst->freq = src->freq;
  75. dst->beacon_int = src->beacon_int;
  76. dst->caps = src->caps;
  77. dst->qual = src->qual;
  78. dst->noise = src->noise;
  79. dst->level = src->level;
  80. dst->tsf = src->tsf;
  81. os_get_time(&dst->last_update);
  82. dst->last_update.sec -= src->age / 1000;
  83. usec = (src->age % 1000) * 1000;
  84. if (dst->last_update.usec < usec) {
  85. dst->last_update.sec--;
  86. dst->last_update.usec += 1000000;
  87. }
  88. dst->last_update.usec -= usec;
  89. }
  90. static void wpa_bss_add(struct wpa_supplicant *wpa_s,
  91. const u8 *ssid, size_t ssid_len,
  92. struct wpa_scan_res *res)
  93. {
  94. struct wpa_bss *bss;
  95. bss = os_zalloc(sizeof(*bss) + res->ie_len);
  96. if (bss == NULL)
  97. return;
  98. bss->id = wpa_s->bss_next_id++;
  99. bss->last_update_idx = wpa_s->bss_update_idx;
  100. wpa_bss_copy_res(bss, res);
  101. os_memcpy(bss->ssid, ssid, ssid_len);
  102. bss->ssid_len = ssid_len;
  103. bss->ie_len = res->ie_len;
  104. os_memcpy(bss + 1, res + 1, res->ie_len);
  105. dl_list_add_tail(&wpa_s->bss, &bss->list);
  106. dl_list_add_tail(&wpa_s->bss_id, &bss->list_id);
  107. wpa_s->num_bss++;
  108. wpa_printf(MSG_DEBUG, "BSS: Add new id %u BSSID " MACSTR " SSID '%s'",
  109. bss->id, MAC2STR(bss->bssid), wpa_ssid_txt(ssid, ssid_len));
  110. wpas_notify_bss_added(wpa_s, bss->bssid, bss->id);
  111. if (wpa_s->num_bss > WPA_BSS_MAX_COUNT) {
  112. /* Remove the oldest entry */
  113. wpa_bss_remove(wpa_s, dl_list_first(&wpa_s->bss,
  114. struct wpa_bss, list));
  115. }
  116. }
  117. static void wpa_bss_update(struct wpa_supplicant *wpa_s, struct wpa_bss *bss,
  118. struct wpa_scan_res *res)
  119. {
  120. bss->scan_miss_count = 0;
  121. bss->last_update_idx = wpa_s->bss_update_idx;
  122. wpa_bss_copy_res(bss, res);
  123. /* Move the entry to the end of the list */
  124. dl_list_del(&bss->list);
  125. if (bss->ie_len >= res->ie_len) {
  126. os_memcpy(bss + 1, res + 1, res->ie_len);
  127. bss->ie_len = res->ie_len;
  128. } else {
  129. struct wpa_bss *nbss;
  130. nbss = os_realloc(bss, sizeof(*bss) + res->ie_len);
  131. if (nbss) {
  132. bss = nbss;
  133. os_memcpy(bss + 1, res + 1, res->ie_len);
  134. bss->ie_len = res->ie_len;
  135. }
  136. }
  137. dl_list_add_tail(&wpa_s->bss, &bss->list);
  138. }
  139. void wpa_bss_update_start(struct wpa_supplicant *wpa_s)
  140. {
  141. wpa_s->bss_update_idx++;
  142. wpa_printf(MSG_DEBUG, "BSS: Start scan result update %u",
  143. wpa_s->bss_update_idx);
  144. }
  145. void wpa_bss_update_scan_res(struct wpa_supplicant *wpa_s,
  146. struct wpa_scan_res *res)
  147. {
  148. const u8 *ssid;
  149. struct wpa_bss *bss;
  150. ssid = wpa_scan_get_ie(res, WLAN_EID_SSID);
  151. if (ssid == NULL) {
  152. wpa_printf(MSG_DEBUG, "BSS: No SSID IE included for " MACSTR,
  153. MAC2STR(res->bssid));
  154. return;
  155. }
  156. if (ssid[1] > 32) {
  157. wpa_printf(MSG_DEBUG, "BSS: Too long SSID IE included for "
  158. MACSTR, MAC2STR(res->bssid));
  159. return;
  160. }
  161. /* TODO: add option for ignoring BSSes we are not interested in
  162. * (to save memory) */
  163. bss = wpa_bss_get(wpa_s, res->bssid, ssid + 2, ssid[1]);
  164. if (bss == NULL)
  165. wpa_bss_add(wpa_s, ssid + 2, ssid[1], res);
  166. else
  167. wpa_bss_update(wpa_s, bss, res);
  168. }
  169. static int wpa_bss_included_in_scan(const struct wpa_bss *bss,
  170. const struct scan_info *info)
  171. {
  172. int found;
  173. size_t i;
  174. if (info == NULL)
  175. return 1;
  176. if (info->num_freqs) {
  177. found = 0;
  178. for (i = 0; i < info->num_freqs; i++) {
  179. if (bss->freq == info->freqs[i]) {
  180. found = 1;
  181. break;
  182. }
  183. }
  184. if (!found)
  185. return 0;
  186. }
  187. if (info->num_ssids) {
  188. found = 0;
  189. for (i = 0; i < info->num_ssids; i++) {
  190. const struct wpa_driver_scan_ssid *s = &info->ssids[i];
  191. if ((s->ssid == NULL || s->ssid_len == 0) ||
  192. (s->ssid_len == bss->ssid_len &&
  193. os_memcmp(s->ssid, bss->ssid, bss->ssid_len) ==
  194. 0)) {
  195. found = 1;
  196. break;
  197. }
  198. }
  199. if (!found)
  200. return 0;
  201. }
  202. return 1;
  203. }
  204. void wpa_bss_update_end(struct wpa_supplicant *wpa_s, struct scan_info *info,
  205. int new_scan)
  206. {
  207. struct wpa_bss *bss, *n;
  208. if (!new_scan)
  209. return; /* do not expire entries without new scan */
  210. dl_list_for_each_safe(bss, n, &wpa_s->bss, struct wpa_bss, list) {
  211. if (!wpa_bss_included_in_scan(bss, info))
  212. continue; /* expire only BSSes that were scanned */
  213. if (bss->last_update_idx < wpa_s->bss_update_idx)
  214. bss->scan_miss_count++;
  215. if (bss->scan_miss_count >= WPA_BSS_EXPIRATION_SCAN_COUNT) {
  216. wpa_printf(MSG_DEBUG, "BSS: Expire BSS %u due to no "
  217. "match in scan", bss->id);
  218. wpa_bss_remove(wpa_s, bss);
  219. }
  220. }
  221. }
  222. static void wpa_bss_timeout(void *eloop_ctx, void *timeout_ctx)
  223. {
  224. struct wpa_supplicant *wpa_s = eloop_ctx;
  225. struct wpa_bss *bss, *n;
  226. struct os_time t;
  227. if (dl_list_empty(&wpa_s->bss))
  228. return;
  229. os_get_time(&t);
  230. t.sec -= WPA_BSS_EXPIRATION_AGE;
  231. dl_list_for_each_safe(bss, n, &wpa_s->bss, struct wpa_bss, list) {
  232. if (os_memcmp(bss->bssid, wpa_s->bssid, ETH_ALEN) == 0 ||
  233. os_memcmp(bss->bssid, wpa_s->pending_bssid, ETH_ALEN) == 0)
  234. 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",
  237. bss->id);
  238. wpa_bss_remove(wpa_s, bss);
  239. } else
  240. break;
  241. }
  242. eloop_register_timeout(WPA_BSS_EXPIRATION_PERIOD, 0,
  243. wpa_bss_timeout, wpa_s, NULL);
  244. }
  245. int wpa_bss_init(struct wpa_supplicant *wpa_s)
  246. {
  247. dl_list_init(&wpa_s->bss);
  248. dl_list_init(&wpa_s->bss_id);
  249. eloop_register_timeout(WPA_BSS_EXPIRATION_PERIOD, 0,
  250. wpa_bss_timeout, wpa_s, NULL);
  251. return 0;
  252. }
  253. void wpa_bss_deinit(struct wpa_supplicant *wpa_s)
  254. {
  255. struct wpa_bss *bss, *n;
  256. eloop_cancel_timeout(wpa_bss_timeout, wpa_s, NULL);
  257. if (wpa_s->bss.next == NULL)
  258. return; /* BSS table not yet initialized */
  259. dl_list_for_each_safe(bss, n, &wpa_s->bss, struct wpa_bss, list)
  260. wpa_bss_remove(wpa_s, bss);
  261. }
  262. struct wpa_bss * wpa_bss_get_bssid(struct wpa_supplicant *wpa_s,
  263. const u8 *bssid)
  264. {
  265. struct wpa_bss *bss;
  266. dl_list_for_each(bss, &wpa_s->bss, struct wpa_bss, list) {
  267. if (os_memcmp(bss->bssid, bssid, ETH_ALEN) == 0)
  268. return bss;
  269. }
  270. return NULL;
  271. }
  272. struct wpa_bss * wpa_bss_get_id(struct wpa_supplicant *wpa_s, unsigned int id)
  273. {
  274. struct wpa_bss *bss;
  275. dl_list_for_each(bss, &wpa_s->bss, struct wpa_bss, list) {
  276. if (bss->id == id)
  277. return bss;
  278. }
  279. return NULL;
  280. }
  281. const u8 * wpa_bss_get_ie(const struct wpa_bss *bss, u8 ie)
  282. {
  283. const u8 *end, *pos;
  284. pos = (const u8 *) (bss + 1);
  285. end = pos + bss->ie_len;
  286. while (pos + 1 < end) {
  287. if (pos + 2 + pos[1] > end)
  288. break;
  289. if (pos[0] == ie)
  290. return pos;
  291. pos += 2 + pos[1];
  292. }
  293. return NULL;
  294. }
  295. const u8 * wpa_bss_get_vendor_ie(const struct wpa_bss *bss, u32 vendor_type)
  296. {
  297. const u8 *end, *pos;
  298. pos = (const u8 *) (bss + 1);
  299. end = pos + bss->ie_len;
  300. while (pos + 1 < end) {
  301. if (pos + 2 + pos[1] > end)
  302. break;
  303. if (pos[0] == WLAN_EID_VENDOR_SPECIFIC && pos[1] >= 4 &&
  304. vendor_type == WPA_GET_BE32(&pos[2]))
  305. return pos;
  306. pos += 2 + pos[1];
  307. }
  308. return NULL;
  309. }
  310. struct wpabuf * wpa_bss_get_vendor_ie_multi(const struct wpa_bss *bss,
  311. u32 vendor_type)
  312. {
  313. struct wpabuf *buf;
  314. const u8 *end, *pos;
  315. buf = wpabuf_alloc(bss->ie_len);
  316. if (buf == NULL)
  317. return NULL;
  318. pos = (const u8 *) (bss + 1);
  319. end = pos + bss->ie_len;
  320. while (pos + 1 < end) {
  321. if (pos + 2 + pos[1] > end)
  322. break;
  323. if (pos[0] == WLAN_EID_VENDOR_SPECIFIC && pos[1] >= 4 &&
  324. vendor_type == WPA_GET_BE32(&pos[2]))
  325. wpabuf_put_data(buf, pos + 2 + 4, pos[1] - 4);
  326. pos += 2 + pos[1];
  327. }
  328. if (wpabuf_len(buf) == 0) {
  329. wpabuf_free(buf);
  330. buf = NULL;
  331. }
  332. return buf;
  333. }
  334. int wpa_bss_get_max_rate(const struct wpa_bss *bss)
  335. {
  336. int rate = 0;
  337. const u8 *ie;
  338. int i;
  339. ie = wpa_bss_get_ie(bss, WLAN_EID_SUPP_RATES);
  340. for (i = 0; ie && i < ie[1]; i++) {
  341. if ((ie[i + 2] & 0x7f) > rate)
  342. rate = ie[i + 2] & 0x7f;
  343. }
  344. ie = wpa_bss_get_ie(bss, WLAN_EID_EXT_SUPP_RATES);
  345. for (i = 0; ie && i < ie[1]; i++) {
  346. if ((ie[i + 2] & 0x7f) > rate)
  347. rate = ie[i + 2] & 0x7f;
  348. }
  349. return rate;
  350. }