bss.c revision 214734
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 15#include "utils/includes.h" 16 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" 22#include "config.h" 23#include "notify.h" 24#include "scan.h" 25#include "bss.h" 26 27 28/** 29 * WPA_BSS_EXPIRATION_PERIOD - Period of expiration run in seconds 30 */ 31#define WPA_BSS_EXPIRATION_PERIOD 10 32 33/** 34 * WPA_BSS_EXPIRATION_AGE - BSS entry age after which it can be expired 35 * 36 * This value control the time in seconds after which a BSS entry gets removed 37 * if it has not been updated or is not in use. 38 */ 39#define WPA_BSS_EXPIRATION_AGE 180 40 41/** 42 * WPA_BSS_EXPIRATION_SCAN_COUNT - Expire BSS after number of scans 43 * 44 * If the BSS entry has not been seen in this many scans, it will be removed. 45 * Value 1 means that the entry is removed after the first scan without the 46 * BSSID being seen. Larger values can be used to avoid BSS entries 47 * disappearing if they are not visible in every scan (e.g., low signal quality 48 * or interference). 49 */ 50#define WPA_BSS_EXPIRATION_SCAN_COUNT 2 51 52#define WPA_BSS_FREQ_CHANGED_FLAG BIT(0) 53#define WPA_BSS_SIGNAL_CHANGED_FLAG BIT(1) 54#define WPA_BSS_PRIVACY_CHANGED_FLAG BIT(2) 55#define WPA_BSS_MODE_CHANGED_FLAG BIT(3) 56#define WPA_BSS_WPAIE_CHANGED_FLAG BIT(4) 57#define WPA_BSS_RSNIE_CHANGED_FLAG BIT(5) 58#define WPA_BSS_WPS_CHANGED_FLAG BIT(6) 59#define WPA_BSS_RATES_CHANGED_FLAG BIT(7) 60#define WPA_BSS_IES_CHANGED_FLAG BIT(8) 61 62 63static void wpa_bss_remove(struct wpa_supplicant *wpa_s, struct wpa_bss *bss) 64{ 65 dl_list_del(&bss->list); 66 dl_list_del(&bss->list_id); 67 wpa_s->num_bss--; 68 wpa_printf(MSG_DEBUG, "BSS: Remove id %u BSSID " MACSTR " SSID '%s'", 69 bss->id, MAC2STR(bss->bssid), 70 wpa_ssid_txt(bss->ssid, bss->ssid_len)); 71 wpas_notify_bss_removed(wpa_s, bss->bssid, bss->id); 72 os_free(bss); 73} 74 75 76struct wpa_bss * wpa_bss_get(struct wpa_supplicant *wpa_s, const u8 *bssid, 77 const u8 *ssid, size_t ssid_len) 78{ 79 struct wpa_bss *bss; 80 dl_list_for_each(bss, &wpa_s->bss, struct wpa_bss, list) { 81 if (os_memcmp(bss->bssid, bssid, ETH_ALEN) == 0 && 82 bss->ssid_len == ssid_len && 83 os_memcmp(bss->ssid, ssid, ssid_len) == 0) 84 return bss; 85 } 86 return NULL; 87} 88 89 90static void wpa_bss_copy_res(struct wpa_bss *dst, struct wpa_scan_res *src) 91{ 92 os_time_t usec; 93 94 dst->flags = src->flags; 95 os_memcpy(dst->bssid, src->bssid, ETH_ALEN); 96 dst->freq = src->freq; 97 dst->beacon_int = src->beacon_int; 98 dst->caps = src->caps; 99 dst->qual = src->qual; 100 dst->noise = src->noise; 101 dst->level = src->level; 102 dst->tsf = src->tsf; 103 104 os_get_time(&dst->last_update); 105 dst->last_update.sec -= src->age / 1000; 106 usec = (src->age % 1000) * 1000; 107 if (dst->last_update.usec < usec) { 108 dst->last_update.sec--; 109 dst->last_update.usec += 1000000; 110 } 111 dst->last_update.usec -= usec; 112} 113 114 115static void wpa_bss_add(struct wpa_supplicant *wpa_s, 116 const u8 *ssid, size_t ssid_len, 117 struct wpa_scan_res *res) 118{ 119 struct wpa_bss *bss; 120 121 bss = os_zalloc(sizeof(*bss) + res->ie_len + res->beacon_ie_len); 122 if (bss == NULL) 123 return; 124 bss->id = wpa_s->bss_next_id++; 125 bss->last_update_idx = wpa_s->bss_update_idx; 126 wpa_bss_copy_res(bss, res); 127 os_memcpy(bss->ssid, ssid, ssid_len); 128 bss->ssid_len = ssid_len; 129 bss->ie_len = res->ie_len; 130 bss->beacon_ie_len = res->beacon_ie_len; 131 os_memcpy(bss + 1, res + 1, res->ie_len + res->beacon_ie_len); 132 133 dl_list_add_tail(&wpa_s->bss, &bss->list); 134 dl_list_add_tail(&wpa_s->bss_id, &bss->list_id); 135 wpa_s->num_bss++; 136 wpa_printf(MSG_DEBUG, "BSS: Add new id %u BSSID " MACSTR " SSID '%s'", 137 bss->id, MAC2STR(bss->bssid), wpa_ssid_txt(ssid, ssid_len)); 138 wpas_notify_bss_added(wpa_s, bss->bssid, bss->id); 139 if (wpa_s->num_bss > wpa_s->conf->bss_max_count) { 140 /* Remove the oldest entry */ 141 wpa_bss_remove(wpa_s, dl_list_first(&wpa_s->bss, 142 struct wpa_bss, list)); 143 } 144} 145 146 147static int are_ies_equal(const struct wpa_bss *old, 148 const struct wpa_scan_res *new, u32 ie) 149{ 150 const u8 *old_ie, *new_ie; 151 struct wpabuf *old_ie_buff = NULL; 152 struct wpabuf *new_ie_buff = NULL; 153 int new_ie_len, old_ie_len, ret, is_multi; 154 155 switch (ie) { 156 case WPA_IE_VENDOR_TYPE: 157 old_ie = wpa_bss_get_vendor_ie(old, ie); 158 new_ie = wpa_scan_get_vendor_ie(new, ie); 159 is_multi = 0; 160 break; 161 case WPS_IE_VENDOR_TYPE: 162 old_ie_buff = wpa_bss_get_vendor_ie_multi(old, ie); 163 new_ie_buff = wpa_scan_get_vendor_ie_multi(new, ie); 164 is_multi = 1; 165 break; 166 case WLAN_EID_RSN: 167 case WLAN_EID_SUPP_RATES: 168 case WLAN_EID_EXT_SUPP_RATES: 169 old_ie = wpa_bss_get_ie(old, ie); 170 new_ie = wpa_scan_get_ie(new, ie); 171 is_multi = 0; 172 break; 173 default: 174 wpa_printf(MSG_DEBUG, "bss: %s: cannot compare IEs", __func__); 175 return 0; 176 } 177 178 if (is_multi) { 179 /* in case of multiple IEs stored in buffer */ 180 old_ie = old_ie_buff ? wpabuf_head_u8(old_ie_buff) : NULL; 181 new_ie = new_ie_buff ? wpabuf_head_u8(new_ie_buff) : NULL; 182 old_ie_len = old_ie_buff ? wpabuf_len(old_ie_buff) : 0; 183 new_ie_len = new_ie_buff ? wpabuf_len(new_ie_buff) : 0; 184 } else { 185 /* in case of single IE */ 186 old_ie_len = old_ie ? old_ie[1] + 2 : 0; 187 new_ie_len = new_ie ? new_ie[1] + 2 : 0; 188 } 189 190 ret = (old_ie_len == new_ie_len && 191 os_memcmp(old_ie, new_ie, old_ie_len) == 0); 192 193 wpabuf_free(old_ie_buff); 194 wpabuf_free(new_ie_buff); 195 196 return ret; 197} 198 199 200static u32 wpa_bss_compare_res(const struct wpa_bss *old, 201 const struct wpa_scan_res *new) 202{ 203 u32 changes = 0; 204 int caps_diff = old->caps ^ new->caps; 205 206 if (old->freq != new->freq) 207 changes |= WPA_BSS_FREQ_CHANGED_FLAG; 208 209 if (old->level != new->level) 210 changes |= WPA_BSS_SIGNAL_CHANGED_FLAG; 211 212 if (caps_diff & IEEE80211_CAP_PRIVACY) 213 changes |= WPA_BSS_PRIVACY_CHANGED_FLAG; 214 215 if (caps_diff & IEEE80211_CAP_IBSS) 216 changes |= WPA_BSS_MODE_CHANGED_FLAG; 217 218 if (old->ie_len == new->ie_len && 219 os_memcmp(old + 1, new + 1, old->ie_len) == 0) 220 return changes; 221 changes |= WPA_BSS_IES_CHANGED_FLAG; 222 223 if (!are_ies_equal(old, new, WPA_IE_VENDOR_TYPE)) 224 changes |= WPA_BSS_WPAIE_CHANGED_FLAG; 225 226 if (!are_ies_equal(old, new, WLAN_EID_RSN)) 227 changes |= WPA_BSS_RSNIE_CHANGED_FLAG; 228 229 if (!are_ies_equal(old, new, WPS_IE_VENDOR_TYPE)) 230 changes |= WPA_BSS_WPS_CHANGED_FLAG; 231 232 if (!are_ies_equal(old, new, WLAN_EID_SUPP_RATES) || 233 !are_ies_equal(old, new, WLAN_EID_EXT_SUPP_RATES)) 234 changes |= WPA_BSS_RATES_CHANGED_FLAG; 235 236 return changes; 237} 238 239 240static void notify_bss_changes(struct wpa_supplicant *wpa_s, u32 changes, 241 const struct wpa_bss *bss) 242{ 243 if (changes & WPA_BSS_FREQ_CHANGED_FLAG) 244 wpas_notify_bss_freq_changed(wpa_s, bss->id); 245 246 if (changes & WPA_BSS_SIGNAL_CHANGED_FLAG) 247 wpas_notify_bss_signal_changed(wpa_s, bss->id); 248 249 if (changes & WPA_BSS_PRIVACY_CHANGED_FLAG) 250 wpas_notify_bss_privacy_changed(wpa_s, bss->id); 251 252 if (changes & WPA_BSS_MODE_CHANGED_FLAG) 253 wpas_notify_bss_mode_changed(wpa_s, bss->id); 254 255 if (changes & WPA_BSS_WPAIE_CHANGED_FLAG) 256 wpas_notify_bss_wpaie_changed(wpa_s, bss->id); 257 258 if (changes & WPA_BSS_RSNIE_CHANGED_FLAG) 259 wpas_notify_bss_rsnie_changed(wpa_s, bss->id); 260 261 if (changes & WPA_BSS_WPS_CHANGED_FLAG) 262 wpas_notify_bss_wps_changed(wpa_s, bss->id); 263 264 if (changes & WPA_BSS_IES_CHANGED_FLAG) 265 wpas_notify_bss_ies_changed(wpa_s, bss->id); 266 267 if (changes & WPA_BSS_RATES_CHANGED_FLAG) 268 wpas_notify_bss_rates_changed(wpa_s, bss->id); 269} 270 271 272static void wpa_bss_update(struct wpa_supplicant *wpa_s, struct wpa_bss *bss, 273 struct wpa_scan_res *res) 274{ 275 u32 changes; 276 277 changes = wpa_bss_compare_res(bss, res); 278 bss->scan_miss_count = 0; 279 bss->last_update_idx = wpa_s->bss_update_idx; 280 wpa_bss_copy_res(bss, res); 281 /* Move the entry to the end of the list */ 282 dl_list_del(&bss->list); 283 if (bss->ie_len + bss->beacon_ie_len >= 284 res->ie_len + res->beacon_ie_len) { 285 os_memcpy(bss + 1, res + 1, res->ie_len + res->beacon_ie_len); 286 bss->ie_len = res->ie_len; 287 bss->beacon_ie_len = res->beacon_ie_len; 288 } else { 289 struct wpa_bss *nbss; 290 struct dl_list *prev = bss->list_id.prev; 291 dl_list_del(&bss->list_id); 292 nbss = os_realloc(bss, sizeof(*bss) + res->ie_len + 293 res->beacon_ie_len); 294 if (nbss) { 295 bss = nbss; 296 os_memcpy(bss + 1, res + 1, 297 res->ie_len + res->beacon_ie_len); 298 bss->ie_len = res->ie_len; 299 bss->beacon_ie_len = res->beacon_ie_len; 300 } 301 dl_list_add(prev, &bss->list_id); 302 } 303 dl_list_add_tail(&wpa_s->bss, &bss->list); 304 305 notify_bss_changes(wpa_s, changes, bss); 306} 307 308 309static int wpa_bss_in_use(struct wpa_supplicant *wpa_s, struct wpa_bss *bss) 310{ 311 return bss == wpa_s->current_bss || 312 os_memcmp(bss->bssid, wpa_s->bssid, ETH_ALEN) == 0 || 313 os_memcmp(bss->bssid, wpa_s->pending_bssid, ETH_ALEN) == 0; 314} 315 316 317void wpa_bss_update_start(struct wpa_supplicant *wpa_s) 318{ 319 wpa_s->bss_update_idx++; 320 wpa_printf(MSG_DEBUG, "BSS: Start scan result update %u", 321 wpa_s->bss_update_idx); 322} 323 324 325void wpa_bss_update_scan_res(struct wpa_supplicant *wpa_s, 326 struct wpa_scan_res *res) 327{ 328 const u8 *ssid; 329 struct wpa_bss *bss; 330 331 ssid = wpa_scan_get_ie(res, WLAN_EID_SSID); 332 if (ssid == NULL) { 333 wpa_printf(MSG_DEBUG, "BSS: No SSID IE included for " MACSTR, 334 MAC2STR(res->bssid)); 335 return; 336 } 337 if (ssid[1] > 32) { 338 wpa_printf(MSG_DEBUG, "BSS: Too long SSID IE included for " 339 MACSTR, MAC2STR(res->bssid)); 340 return; 341 } 342 343 /* TODO: add option for ignoring BSSes we are not interested in 344 * (to save memory) */ 345 bss = wpa_bss_get(wpa_s, res->bssid, ssid + 2, ssid[1]); 346 if (bss == NULL) 347 wpa_bss_add(wpa_s, ssid + 2, ssid[1], res); 348 else 349 wpa_bss_update(wpa_s, bss, res); 350} 351 352 353static int wpa_bss_included_in_scan(const struct wpa_bss *bss, 354 const struct scan_info *info) 355{ 356 int found; 357 size_t i; 358 359 if (info == NULL) 360 return 1; 361 362 if (info->num_freqs) { 363 found = 0; 364 for (i = 0; i < info->num_freqs; i++) { 365 if (bss->freq == info->freqs[i]) { 366 found = 1; 367 break; 368 } 369 } 370 if (!found) 371 return 0; 372 } 373 374 if (info->num_ssids) { 375 found = 0; 376 for (i = 0; i < info->num_ssids; i++) { 377 const struct wpa_driver_scan_ssid *s = &info->ssids[i]; 378 if ((s->ssid == NULL || s->ssid_len == 0) || 379 (s->ssid_len == bss->ssid_len && 380 os_memcmp(s->ssid, bss->ssid, bss->ssid_len) == 381 0)) { 382 found = 1; 383 break; 384 } 385 } 386 if (!found) 387 return 0; 388 } 389 390 return 1; 391} 392 393 394void wpa_bss_update_end(struct wpa_supplicant *wpa_s, struct scan_info *info, 395 int new_scan) 396{ 397 struct wpa_bss *bss, *n; 398 399 if (!new_scan) 400 return; /* do not expire entries without new scan */ 401 402 dl_list_for_each_safe(bss, n, &wpa_s->bss, struct wpa_bss, list) { 403 if (wpa_bss_in_use(wpa_s, bss)) 404 continue; 405 if (!wpa_bss_included_in_scan(bss, info)) 406 continue; /* expire only BSSes that were scanned */ 407 if (bss->last_update_idx < wpa_s->bss_update_idx) 408 bss->scan_miss_count++; 409 if (bss->scan_miss_count >= WPA_BSS_EXPIRATION_SCAN_COUNT) { 410 wpa_printf(MSG_DEBUG, "BSS: Expire BSS %u due to no " 411 "match in scan", bss->id); 412 wpa_bss_remove(wpa_s, bss); 413 } 414 } 415} 416 417 418static void wpa_bss_timeout(void *eloop_ctx, void *timeout_ctx) 419{ 420 struct wpa_supplicant *wpa_s = eloop_ctx; 421 struct wpa_bss *bss, *n; 422 struct os_time t; 423 424 if (dl_list_empty(&wpa_s->bss)) 425 return; 426 427 os_get_time(&t); 428 t.sec -= WPA_BSS_EXPIRATION_AGE; 429 430 dl_list_for_each_safe(bss, n, &wpa_s->bss, struct wpa_bss, list) { 431 if (wpa_bss_in_use(wpa_s, bss)) 432 continue; 433 434 if (os_time_before(&bss->last_update, &t)) { 435 wpa_printf(MSG_DEBUG, "BSS: Expire BSS %u due to age", 436 bss->id); 437 wpa_bss_remove(wpa_s, bss); 438 } else 439 break; 440 } 441 eloop_register_timeout(WPA_BSS_EXPIRATION_PERIOD, 0, 442 wpa_bss_timeout, wpa_s, NULL); 443} 444 445 446int wpa_bss_init(struct wpa_supplicant *wpa_s) 447{ 448 dl_list_init(&wpa_s->bss); 449 dl_list_init(&wpa_s->bss_id); 450 eloop_register_timeout(WPA_BSS_EXPIRATION_PERIOD, 0, 451 wpa_bss_timeout, wpa_s, NULL); 452 return 0; 453} 454 455 456void wpa_bss_deinit(struct wpa_supplicant *wpa_s) 457{ 458 struct wpa_bss *bss, *n; 459 eloop_cancel_timeout(wpa_bss_timeout, wpa_s, NULL); 460 if (wpa_s->bss.next == NULL) 461 return; /* BSS table not yet initialized */ 462 dl_list_for_each_safe(bss, n, &wpa_s->bss, struct wpa_bss, list) 463 wpa_bss_remove(wpa_s, bss); 464} 465 466 467struct wpa_bss * wpa_bss_get_bssid(struct wpa_supplicant *wpa_s, 468 const u8 *bssid) 469{ 470 struct wpa_bss *bss; 471 dl_list_for_each(bss, &wpa_s->bss, struct wpa_bss, list) { 472 if (os_memcmp(bss->bssid, bssid, ETH_ALEN) == 0) 473 return bss; 474 } 475 return NULL; 476} 477 478 479struct wpa_bss * wpa_bss_get_id(struct wpa_supplicant *wpa_s, unsigned int id) 480{ 481 struct wpa_bss *bss; 482 dl_list_for_each(bss, &wpa_s->bss, struct wpa_bss, list) { 483 if (bss->id == id) 484 return bss; 485 } 486 return NULL; 487} 488 489 490const u8 * wpa_bss_get_ie(const struct wpa_bss *bss, u8 ie) 491{ 492 const u8 *end, *pos; 493 494 pos = (const u8 *) (bss + 1); 495 end = pos + bss->ie_len; 496 497 while (pos + 1 < end) { 498 if (pos + 2 + pos[1] > end) 499 break; 500 if (pos[0] == ie) 501 return pos; 502 pos += 2 + pos[1]; 503 } 504 505 return NULL; 506} 507 508 509const u8 * wpa_bss_get_vendor_ie(const struct wpa_bss *bss, u32 vendor_type) 510{ 511 const u8 *end, *pos; 512 513 pos = (const u8 *) (bss + 1); 514 end = pos + bss->ie_len; 515 516 while (pos + 1 < end) { 517 if (pos + 2 + pos[1] > end) 518 break; 519 if (pos[0] == WLAN_EID_VENDOR_SPECIFIC && pos[1] >= 4 && 520 vendor_type == WPA_GET_BE32(&pos[2])) 521 return pos; 522 pos += 2 + pos[1]; 523 } 524 525 return NULL; 526} 527 528 529struct wpabuf * wpa_bss_get_vendor_ie_multi(const struct wpa_bss *bss, 530 u32 vendor_type) 531{ 532 struct wpabuf *buf; 533 const u8 *end, *pos; 534 535 buf = wpabuf_alloc(bss->ie_len); 536 if (buf == NULL) 537 return NULL; 538 539 pos = (const u8 *) (bss + 1); 540 end = pos + bss->ie_len; 541 542 while (pos + 1 < end) { 543 if (pos + 2 + pos[1] > end) 544 break; 545 if (pos[0] == WLAN_EID_VENDOR_SPECIFIC && pos[1] >= 4 && 546 vendor_type == WPA_GET_BE32(&pos[2])) 547 wpabuf_put_data(buf, pos + 2 + 4, pos[1] - 4); 548 pos += 2 + pos[1]; 549 } 550 551 if (wpabuf_len(buf) == 0) { 552 wpabuf_free(buf); 553 buf = NULL; 554 } 555 556 return buf; 557} 558 559 560int wpa_bss_get_max_rate(const struct wpa_bss *bss) 561{ 562 int rate = 0; 563 const u8 *ie; 564 int i; 565 566 ie = wpa_bss_get_ie(bss, WLAN_EID_SUPP_RATES); 567 for (i = 0; ie && i < ie[1]; i++) { 568 if ((ie[i + 2] & 0x7f) > rate) 569 rate = ie[i + 2] & 0x7f; 570 } 571 572 ie = wpa_bss_get_ie(bss, WLAN_EID_EXT_SUPP_RATES); 573 for (i = 0; ie && i < ie[1]; i++) { 574 if ((ie[i + 2] & 0x7f) > rate) 575 rate = ie[i + 2] & 0x7f; 576 } 577 578 return rate; 579} 580 581 582int wpa_bss_get_bit_rates(const struct wpa_bss *bss, u8 **rates) 583{ 584 const u8 *ie, *ie2; 585 int i, j; 586 unsigned int len; 587 u8 *r; 588 589 ie = wpa_bss_get_ie(bss, WLAN_EID_SUPP_RATES); 590 ie2 = wpa_bss_get_ie(bss, WLAN_EID_EXT_SUPP_RATES); 591 592 len = (ie ? ie[1] : 0) + (ie2 ? ie2[1] : 0); 593 594 r = os_malloc(len); 595 if (!r) 596 return -1; 597 598 for (i = 0; ie && i < ie[1]; i++) 599 r[i] = ie[i + 2] & 0x7f; 600 601 for (j = 0; ie2 && j < ie2[1]; j++) 602 r[i + j] = ie2[j + 2] & 0x7f; 603 604 *rates = r; 605 return len; 606} 607