1 /* 2 * Scanning implementation 3 * 4 * Copyright 2003, Jouni Malinen <jkmaline@cc.hut.fi> 5 * Copyright 2004, Instant802 Networks, Inc. 6 * Copyright 2005, Devicescape Software, Inc. 7 * Copyright 2006-2007 Jiri Benc <jbenc@suse.cz> 8 * Copyright 2007, Michael Wu <flamingice@sourmilk.net> 9 * 10 * This program is free software; you can redistribute it and/or modify 11 * it under the terms of the GNU General Public License version 2 as 12 * published by the Free Software Foundation. 13 */ 14 15 #include <linux/wireless.h> 16 #include <linux/if_arp.h> 17 #include <linux/rtnetlink.h> 18 #include <net/mac80211.h> 19 20 #include "ieee80211_i.h" 21 #include "driver-ops.h" 22 #include "mesh.h" 23 24 #define IEEE80211_PROBE_DELAY (HZ / 33) 25 #define IEEE80211_CHANNEL_TIME (HZ / 33) 26 #define IEEE80211_PASSIVE_CHANNEL_TIME (HZ / 8) 27 28 struct ieee80211_bss * 29 ieee80211_rx_bss_get(struct ieee80211_local *local, u8 *bssid, int freq, 30 u8 *ssid, u8 ssid_len) 31 { 32 return (void *)cfg80211_get_bss(local->hw.wiphy, 33 ieee80211_get_channel(local->hw.wiphy, 34 freq), 35 bssid, ssid, ssid_len, 36 0, 0); 37 } 38 39 static void ieee80211_rx_bss_free(struct cfg80211_bss *cbss) 40 { 41 struct ieee80211_bss *bss = (void *)cbss; 42 43 kfree(bss_mesh_id(bss)); 44 kfree(bss_mesh_cfg(bss)); 45 } 46 47 void ieee80211_rx_bss_put(struct ieee80211_local *local, 48 struct ieee80211_bss *bss) 49 { 50 cfg80211_put_bss((struct cfg80211_bss *)bss); 51 } 52 53 struct ieee80211_bss * 54 ieee80211_bss_info_update(struct ieee80211_local *local, 55 struct ieee80211_rx_status *rx_status, 56 struct ieee80211_mgmt *mgmt, 57 size_t len, 58 struct ieee802_11_elems *elems, 59 struct ieee80211_channel *channel, 60 bool beacon) 61 { 62 struct ieee80211_bss *bss; 63 int clen; 64 s32 signal = 0; 65 66 if (local->hw.flags & IEEE80211_HW_SIGNAL_DBM) 67 signal = rx_status->signal * 100; 68 else if (local->hw.flags & IEEE80211_HW_SIGNAL_UNSPEC) 69 signal = (rx_status->signal * 100) / local->hw.max_signal; 70 71 bss = (void *)cfg80211_inform_bss_frame(local->hw.wiphy, channel, 72 mgmt, len, signal, GFP_ATOMIC); 73 74 if (!bss) 75 return NULL; 76 77 bss->cbss.free_priv = ieee80211_rx_bss_free; 78 79 /* save the ERP value so that it is available at association time */ 80 if (elems->erp_info && elems->erp_info_len >= 1) { 81 bss->erp_value = elems->erp_info[0]; 82 bss->has_erp_value = 1; 83 } 84 85 if (elems->tim) { 86 struct ieee80211_tim_ie *tim_ie = 87 (struct ieee80211_tim_ie *)elems->tim; 88 bss->dtim_period = tim_ie->dtim_period; 89 } 90 91 /* set default value for buggy AP/no TIM element */ 92 if (bss->dtim_period == 0) 93 bss->dtim_period = 1; 94 95 bss->supp_rates_len = 0; 96 if (elems->supp_rates) { 97 clen = IEEE80211_MAX_SUPP_RATES - bss->supp_rates_len; 98 if (clen > elems->supp_rates_len) 99 clen = elems->supp_rates_len; 100 memcpy(&bss->supp_rates[bss->supp_rates_len], elems->supp_rates, 101 clen); 102 bss->supp_rates_len += clen; 103 } 104 if (elems->ext_supp_rates) { 105 clen = IEEE80211_MAX_SUPP_RATES - bss->supp_rates_len; 106 if (clen > elems->ext_supp_rates_len) 107 clen = elems->ext_supp_rates_len; 108 memcpy(&bss->supp_rates[bss->supp_rates_len], 109 elems->ext_supp_rates, clen); 110 bss->supp_rates_len += clen; 111 } 112 113 bss->wmm_used = elems->wmm_param || elems->wmm_info; 114 115 if (!beacon) 116 bss->last_probe_resp = jiffies; 117 118 return bss; 119 } 120 121 ieee80211_rx_result 122 ieee80211_scan_rx(struct ieee80211_sub_if_data *sdata, struct sk_buff *skb) 123 { 124 struct ieee80211_rx_status *rx_status = IEEE80211_SKB_RXCB(skb); 125 struct ieee80211_mgmt *mgmt; 126 struct ieee80211_bss *bss; 127 u8 *elements; 128 struct ieee80211_channel *channel; 129 size_t baselen; 130 int freq; 131 __le16 fc; 132 bool presp, beacon = false; 133 struct ieee802_11_elems elems; 134 135 if (skb->len < 2) 136 return RX_DROP_UNUSABLE; 137 138 mgmt = (struct ieee80211_mgmt *) skb->data; 139 fc = mgmt->frame_control; 140 141 if (ieee80211_is_ctl(fc)) 142 return RX_CONTINUE; 143 144 if (skb->len < 24) 145 return RX_DROP_MONITOR; 146 147 presp = ieee80211_is_probe_resp(fc); 148 if (presp) { 149 /* ignore ProbeResp to foreign address */ 150 if (memcmp(mgmt->da, sdata->dev->dev_addr, ETH_ALEN)) 151 return RX_DROP_MONITOR; 152 153 presp = true; 154 elements = mgmt->u.probe_resp.variable; 155 baselen = offsetof(struct ieee80211_mgmt, u.probe_resp.variable); 156 } else { 157 beacon = ieee80211_is_beacon(fc); 158 baselen = offsetof(struct ieee80211_mgmt, u.beacon.variable); 159 elements = mgmt->u.beacon.variable; 160 } 161 162 if (!presp && !beacon) 163 return RX_CONTINUE; 164 165 if (baselen > skb->len) 166 return RX_DROP_MONITOR; 167 168 ieee802_11_parse_elems(elements, skb->len - baselen, &elems); 169 170 if (elems.ds_params && elems.ds_params_len == 1) 171 freq = ieee80211_channel_to_frequency(elems.ds_params[0]); 172 else 173 freq = rx_status->freq; 174 175 channel = ieee80211_get_channel(sdata->local->hw.wiphy, freq); 176 177 if (!channel || channel->flags & IEEE80211_CHAN_DISABLED) 178 return RX_DROP_MONITOR; 179 180 bss = ieee80211_bss_info_update(sdata->local, rx_status, 181 mgmt, skb->len, &elems, 182 channel, beacon); 183 if (bss) 184 ieee80211_rx_bss_put(sdata->local, bss); 185 186 dev_kfree_skb(skb); 187 return RX_QUEUED; 188 } 189 190 /* return false if no more work */ 191 static bool ieee80211_prep_hw_scan(struct ieee80211_local *local) 192 { 193 struct cfg80211_scan_request *req = local->scan_req; 194 enum ieee80211_band band; 195 int i, ielen, n_chans; 196 197 do { 198 if (local->hw_scan_band == IEEE80211_NUM_BANDS) 199 return false; 200 201 band = local->hw_scan_band; 202 n_chans = 0; 203 for (i = 0; i < req->n_channels; i++) { 204 if (req->channels[i]->band == band) { 205 local->hw_scan_req->channels[n_chans] = 206 req->channels[i]; 207 n_chans++; 208 } 209 } 210 211 local->hw_scan_band++; 212 } while (!n_chans); 213 214 local->hw_scan_req->n_channels = n_chans; 215 216 ielen = ieee80211_build_preq_ies(local, (u8 *)local->hw_scan_req->ie, 217 req->ie, req->ie_len, band); 218 local->hw_scan_req->ie_len = ielen; 219 220 return true; 221 } 222 223 /* 224 * inform AP that we will go to sleep so that it will buffer the frames 225 * while we scan 226 */ 227 static void ieee80211_scan_ps_enable(struct ieee80211_sub_if_data *sdata) 228 { 229 struct ieee80211_local *local = sdata->local; 230 231 local->scan_ps_enabled = false; 232 233 /* FIXME: what to do when local->pspolling is true? */ 234 235 del_timer_sync(&local->dynamic_ps_timer); 236 cancel_work_sync(&local->dynamic_ps_enable_work); 237 238 if (local->hw.conf.flags & IEEE80211_CONF_PS) { 239 local->scan_ps_enabled = true; 240 local->hw.conf.flags &= ~IEEE80211_CONF_PS; 241 ieee80211_hw_config(local, IEEE80211_CONF_CHANGE_PS); 242 } 243 244 if (!(local->scan_ps_enabled) || 245 !(local->hw.flags & IEEE80211_HW_PS_NULLFUNC_STACK)) 246 /* 247 * If power save was enabled, no need to send a nullfunc 248 * frame because AP knows that we are sleeping. But if the 249 * hardware is creating the nullfunc frame for power save 250 * status (ie. IEEE80211_HW_PS_NULLFUNC_STACK is not 251 * enabled) and power save was enabled, the firmware just 252 * sent a null frame with power save disabled. So we need 253 * to send a new nullfunc frame to inform the AP that we 254 * are again sleeping. 255 */ 256 ieee80211_send_nullfunc(local, sdata, 1); 257 } 258 259 /* inform AP that we are awake again, unless power save is enabled */ 260 static void ieee80211_scan_ps_disable(struct ieee80211_sub_if_data *sdata) 261 { 262 struct ieee80211_local *local = sdata->local; 263 264 if (!local->ps_sdata) 265 ieee80211_send_nullfunc(local, sdata, 0); 266 else if (local->scan_ps_enabled) { 267 /* 268 * In !IEEE80211_HW_PS_NULLFUNC_STACK case the hardware 269 * will send a nullfunc frame with the powersave bit set 270 * even though the AP already knows that we are sleeping. 271 * This could be avoided by sending a null frame with power 272 * save bit disabled before enabling the power save, but 273 * this doesn't gain anything. 274 * 275 * When IEEE80211_HW_PS_NULLFUNC_STACK is enabled, no need 276 * to send a nullfunc frame because AP already knows that 277 * we are sleeping, let's just enable power save mode in 278 * hardware. 279 */ 280 local->hw.conf.flags |= IEEE80211_CONF_PS; 281 ieee80211_hw_config(local, IEEE80211_CONF_CHANGE_PS); 282 } else if (local->hw.conf.dynamic_ps_timeout > 0) { 283 /* 284 * If IEEE80211_CONF_PS was not set and the dynamic_ps_timer 285 * had been running before leaving the operating channel, 286 * restart the timer now and send a nullfunc frame to inform 287 * the AP that we are awake. 288 */ 289 ieee80211_send_nullfunc(local, sdata, 0); 290 mod_timer(&local->dynamic_ps_timer, jiffies + 291 msecs_to_jiffies(local->hw.conf.dynamic_ps_timeout)); 292 } 293 } 294 295 void ieee80211_scan_completed(struct ieee80211_hw *hw, bool aborted) 296 { 297 struct ieee80211_local *local = hw_to_local(hw); 298 struct ieee80211_sub_if_data *sdata; 299 bool was_hw_scan; 300 301 mutex_lock(&local->scan_mtx); 302 303 /* 304 * It's ok to abort a not-yet-running scan (that 305 * we have one at all will be verified by checking 306 * local->scan_req next), but not to complete it 307 * successfully. 308 */ 309 if (WARN_ON(!local->scanning && !aborted)) 310 aborted = true; 311 312 if (WARN_ON(!local->scan_req)) { 313 mutex_unlock(&local->scan_mtx); 314 return; 315 } 316 317 was_hw_scan = test_bit(SCAN_HW_SCANNING, &local->scanning); 318 if (was_hw_scan && !aborted && ieee80211_prep_hw_scan(local)) { 319 ieee80211_queue_delayed_work(&local->hw, 320 &local->scan_work, 0); 321 mutex_unlock(&local->scan_mtx); 322 return; 323 } 324 325 kfree(local->hw_scan_req); 326 local->hw_scan_req = NULL; 327 328 if (local->scan_req != local->int_scan_req) 329 cfg80211_scan_done(local->scan_req, aborted); 330 local->scan_req = NULL; 331 local->scan_sdata = NULL; 332 333 local->scanning = 0; 334 local->scan_channel = NULL; 335 336 /* we only have to protect scan_req and hw/sw scan */ 337 mutex_unlock(&local->scan_mtx); 338 339 ieee80211_hw_config(local, IEEE80211_CONF_CHANGE_CHANNEL); 340 if (was_hw_scan) 341 goto done; 342 343 ieee80211_configure_filter(local); 344 345 drv_sw_scan_complete(local); 346 347 mutex_lock(&local->iflist_mtx); 348 list_for_each_entry(sdata, &local->interfaces, list) { 349 if (!netif_running(sdata->dev)) 350 continue; 351 352 /* Tell AP we're back */ 353 if (sdata->vif.type == NL80211_IFTYPE_STATION) { 354 if (sdata->u.mgd.associated) { 355 ieee80211_scan_ps_disable(sdata); 356 netif_wake_queue(sdata->dev); 357 } 358 } else 359 netif_wake_queue(sdata->dev); 360 361 /* re-enable beaconing */ 362 if (sdata->vif.type == NL80211_IFTYPE_AP || 363 sdata->vif.type == NL80211_IFTYPE_ADHOC || 364 sdata->vif.type == NL80211_IFTYPE_MESH_POINT) 365 ieee80211_bss_info_change_notify( 366 sdata, BSS_CHANGED_BEACON_ENABLED); 367 } 368 mutex_unlock(&local->iflist_mtx); 369 370 done: 371 ieee80211_recalc_idle(local); 372 ieee80211_mlme_notify_scan_completed(local); 373 ieee80211_ibss_notify_scan_completed(local); 374 ieee80211_mesh_notify_scan_completed(local); 375 } 376 EXPORT_SYMBOL(ieee80211_scan_completed); 377 378 static int ieee80211_start_sw_scan(struct ieee80211_local *local) 379 { 380 struct ieee80211_sub_if_data *sdata; 381 382 /* 383 * Hardware/driver doesn't support hw_scan, so use software 384 * scanning instead. First send a nullfunc frame with power save 385 * bit on so that AP will buffer the frames for us while we are not 386 * listening, then send probe requests to each channel and wait for 387 * the responses. After all channels are scanned, tune back to the 388 * original channel and send a nullfunc frame with power save bit 389 * off to trigger the AP to send us all the buffered frames. 390 * 391 * Note that while local->sw_scanning is true everything else but 392 * nullfunc frames and probe requests will be dropped in 393 * ieee80211_tx_h_check_assoc(). 394 */ 395 drv_sw_scan_start(local); 396 397 mutex_lock(&local->iflist_mtx); 398 list_for_each_entry(sdata, &local->interfaces, list) { 399 if (!netif_running(sdata->dev)) 400 continue; 401 402 /* disable beaconing */ 403 if (sdata->vif.type == NL80211_IFTYPE_AP || 404 sdata->vif.type == NL80211_IFTYPE_ADHOC || 405 sdata->vif.type == NL80211_IFTYPE_MESH_POINT) 406 ieee80211_bss_info_change_notify( 407 sdata, BSS_CHANGED_BEACON_ENABLED); 408 409 /* 410 * only handle non-STA interfaces here, STA interfaces 411 * are handled in the scan state machine 412 */ 413 if (sdata->vif.type != NL80211_IFTYPE_STATION) 414 netif_stop_queue(sdata->dev); 415 } 416 mutex_unlock(&local->iflist_mtx); 417 418 local->next_scan_state = SCAN_DECISION; 419 local->scan_channel_idx = 0; 420 421 ieee80211_configure_filter(local); 422 423 /* TODO: start scan as soon as all nullfunc frames are ACKed */ 424 ieee80211_queue_delayed_work(&local->hw, 425 &local->scan_work, 426 IEEE80211_CHANNEL_TIME); 427 428 return 0; 429 } 430 431 432 static int __ieee80211_start_scan(struct ieee80211_sub_if_data *sdata, 433 struct cfg80211_scan_request *req) 434 { 435 struct ieee80211_local *local = sdata->local; 436 struct ieee80211_if_managed *ifmgd = &sdata->u.mgd; 437 int rc; 438 439 if (local->scan_req) 440 return -EBUSY; 441 442 if (local->ops->hw_scan) { 443 u8 *ies; 444 445 local->hw_scan_req = kmalloc( 446 sizeof(*local->hw_scan_req) + 447 req->n_channels * sizeof(req->channels[0]) + 448 2 + IEEE80211_MAX_SSID_LEN + local->scan_ies_len + 449 req->ie_len, GFP_KERNEL); 450 if (!local->hw_scan_req) 451 return -ENOMEM; 452 453 local->hw_scan_req->ssids = req->ssids; 454 local->hw_scan_req->n_ssids = req->n_ssids; 455 ies = (u8 *)local->hw_scan_req + 456 sizeof(*local->hw_scan_req) + 457 req->n_channels * sizeof(req->channels[0]); 458 local->hw_scan_req->ie = ies; 459 460 local->hw_scan_band = 0; 461 } 462 463 local->scan_req = req; 464 local->scan_sdata = sdata; 465 466 if (req != local->int_scan_req && 467 sdata->vif.type == NL80211_IFTYPE_STATION && 468 !list_empty(&ifmgd->work_list)) { 469 /* actually wait for the work it's doing to finish/time out */ 470 set_bit(IEEE80211_STA_REQ_SCAN, &ifmgd->request); 471 return 0; 472 } 473 474 if (local->ops->hw_scan) 475 __set_bit(SCAN_HW_SCANNING, &local->scanning); 476 else 477 __set_bit(SCAN_SW_SCANNING, &local->scanning); 478 /* 479 * Kicking off the scan need not be protected, 480 * only the scan variable stuff, since now 481 * local->scan_req is assigned and other callers 482 * will abort their scan attempts. 483 * 484 * This avoids getting a scan_mtx -> iflist_mtx 485 * dependency, so that the scan completed calls 486 * have more locking freedom. 487 */ 488 489 ieee80211_recalc_idle(local); 490 mutex_unlock(&local->scan_mtx); 491 492 if (local->ops->hw_scan) { 493 WARN_ON(!ieee80211_prep_hw_scan(local)); 494 rc = drv_hw_scan(local, local->hw_scan_req); 495 } else 496 rc = ieee80211_start_sw_scan(local); 497 498 mutex_lock(&local->scan_mtx); 499 500 if (rc) { 501 kfree(local->hw_scan_req); 502 local->hw_scan_req = NULL; 503 local->scanning = 0; 504 505 ieee80211_recalc_idle(local); 506 507 local->scan_req = NULL; 508 local->scan_sdata = NULL; 509 } 510 511 return rc; 512 } 513 514 static int ieee80211_scan_state_decision(struct ieee80211_local *local, 515 unsigned long *next_delay) 516 { 517 bool associated = false; 518 struct ieee80211_sub_if_data *sdata; 519 520 /* if no more bands/channels left, complete scan and advance to the idle state */ 521 if (local->scan_channel_idx >= local->scan_req->n_channels) { 522 ieee80211_scan_completed(&local->hw, false); 523 return 1; 524 } 525 526 /* check if at least one STA interface is associated */ 527 mutex_lock(&local->iflist_mtx); 528 list_for_each_entry(sdata, &local->interfaces, list) { 529 if (!netif_running(sdata->dev)) 530 continue; 531 532 if (sdata->vif.type == NL80211_IFTYPE_STATION) { 533 if (sdata->u.mgd.associated) { 534 associated = true; 535 break; 536 } 537 } 538 } 539 mutex_unlock(&local->iflist_mtx); 540 541 if (local->scan_channel) { 542 /* 543 * we're currently scanning a different channel, let's 544 * switch back to the operating channel now if at least 545 * one interface is associated. Otherwise just scan the 546 * next channel 547 */ 548 if (associated) 549 local->next_scan_state = SCAN_ENTER_OPER_CHANNEL; 550 else 551 local->next_scan_state = SCAN_SET_CHANNEL; 552 } else { 553 /* 554 * we're on the operating channel currently, let's 555 * leave that channel now to scan another one 556 */ 557 local->next_scan_state = SCAN_LEAVE_OPER_CHANNEL; 558 } 559 560 *next_delay = 0; 561 return 0; 562 } 563 564 static void ieee80211_scan_state_leave_oper_channel(struct ieee80211_local *local, 565 unsigned long *next_delay) 566 { 567 struct ieee80211_sub_if_data *sdata; 568 569 /* 570 * notify the AP about us leaving the channel and stop all STA interfaces 571 */ 572 mutex_lock(&local->iflist_mtx); 573 list_for_each_entry(sdata, &local->interfaces, list) { 574 if (!netif_running(sdata->dev)) 575 continue; 576 577 if (sdata->vif.type == NL80211_IFTYPE_STATION) { 578 netif_stop_queue(sdata->dev); 579 if (sdata->u.mgd.associated) 580 ieee80211_scan_ps_enable(sdata); 581 } 582 } 583 mutex_unlock(&local->iflist_mtx); 584 585 __set_bit(SCAN_OFF_CHANNEL, &local->scanning); 586 587 /* advance to the next channel to be scanned */ 588 *next_delay = HZ / 10; 589 local->next_scan_state = SCAN_SET_CHANNEL; 590 } 591 592 static void ieee80211_scan_state_enter_oper_channel(struct ieee80211_local *local, 593 unsigned long *next_delay) 594 { 595 struct ieee80211_sub_if_data *sdata = local->scan_sdata; 596 597 /* switch back to the operating channel */ 598 local->scan_channel = NULL; 599 ieee80211_hw_config(local, IEEE80211_CONF_CHANGE_CHANNEL); 600 601 /* 602 * notify the AP about us being back and restart all STA interfaces 603 */ 604 mutex_lock(&local->iflist_mtx); 605 list_for_each_entry(sdata, &local->interfaces, list) { 606 if (!netif_running(sdata->dev)) 607 continue; 608 609 /* Tell AP we're back */ 610 if (sdata->vif.type == NL80211_IFTYPE_STATION) { 611 if (sdata->u.mgd.associated) 612 ieee80211_scan_ps_disable(sdata); 613 netif_wake_queue(sdata->dev); 614 } 615 } 616 mutex_unlock(&local->iflist_mtx); 617 618 __clear_bit(SCAN_OFF_CHANNEL, &local->scanning); 619 620 *next_delay = HZ / 5; 621 local->next_scan_state = SCAN_DECISION; 622 } 623 624 static void ieee80211_scan_state_set_channel(struct ieee80211_local *local, 625 unsigned long *next_delay) 626 { 627 int skip; 628 struct ieee80211_channel *chan; 629 630 skip = 0; 631 chan = local->scan_req->channels[local->scan_channel_idx]; 632 633 local->scan_channel = chan; 634 if (ieee80211_hw_config(local, IEEE80211_CONF_CHANGE_CHANNEL)) 635 skip = 1; 636 637 /* advance state machine to next channel/band */ 638 local->scan_channel_idx++; 639 640 if (skip) { 641 /* if we skip this channel return to the decision state */ 642 local->next_scan_state = SCAN_DECISION; 643 return; 644 } 645 646 /* 647 * Probe delay is used to update the NAV, cf. 11.1.3.2.2 648 * (which unfortunately doesn't say _why_ step a) is done, 649 * but it waits for the probe delay or until a frame is 650 * received - and the received frame would update the NAV). 651 * For now, we do not support waiting until a frame is 652 * received. 653 * 654 * In any case, it is not necessary for a passive scan. 655 */ 656 if (chan->flags & IEEE80211_CHAN_PASSIVE_SCAN || 657 !local->scan_req->n_ssids) { 658 *next_delay = IEEE80211_PASSIVE_CHANNEL_TIME; 659 local->next_scan_state = SCAN_DECISION; 660 return; 661 } 662 663 /* active scan, send probes */ 664 *next_delay = IEEE80211_PROBE_DELAY; 665 local->next_scan_state = SCAN_SEND_PROBE; 666 } 667 668 static void ieee80211_scan_state_send_probe(struct ieee80211_local *local, 669 unsigned long *next_delay) 670 { 671 int i; 672 struct ieee80211_sub_if_data *sdata = local->scan_sdata; 673 674 for (i = 0; i < local->scan_req->n_ssids; i++) 675 ieee80211_send_probe_req( 676 sdata, NULL, 677 local->scan_req->ssids[i].ssid, 678 local->scan_req->ssids[i].ssid_len, 679 local->scan_req->ie, local->scan_req->ie_len); 680 681 /* 682 * After sending probe requests, wait for probe responses 683 * on the channel. 684 */ 685 *next_delay = IEEE80211_CHANNEL_TIME; 686 local->next_scan_state = SCAN_DECISION; 687 } 688 689 void ieee80211_scan_work(struct work_struct *work) 690 { 691 struct ieee80211_local *local = 692 container_of(work, struct ieee80211_local, scan_work.work); 693 struct ieee80211_sub_if_data *sdata = local->scan_sdata; 694 unsigned long next_delay = 0; 695 696 mutex_lock(&local->scan_mtx); 697 if (!sdata || !local->scan_req) { 698 mutex_unlock(&local->scan_mtx); 699 return; 700 } 701 702 if (local->hw_scan_req) { 703 int rc = drv_hw_scan(local, local->hw_scan_req); 704 mutex_unlock(&local->scan_mtx); 705 if (rc) 706 ieee80211_scan_completed(&local->hw, true); 707 return; 708 } 709 710 if (local->scan_req && !local->scanning) { 711 struct cfg80211_scan_request *req = local->scan_req; 712 int rc; 713 714 local->scan_req = NULL; 715 local->scan_sdata = NULL; 716 717 rc = __ieee80211_start_scan(sdata, req); 718 mutex_unlock(&local->scan_mtx); 719 720 if (rc) 721 ieee80211_scan_completed(&local->hw, true); 722 return; 723 } 724 725 mutex_unlock(&local->scan_mtx); 726 727 /* 728 * Avoid re-scheduling when the sdata is going away. 729 */ 730 if (!netif_running(sdata->dev)) { 731 ieee80211_scan_completed(&local->hw, true); 732 return; 733 } 734 735 /* 736 * as long as no delay is required advance immediately 737 * without scheduling a new work 738 */ 739 do { 740 switch (local->next_scan_state) { 741 case SCAN_DECISION: 742 if (ieee80211_scan_state_decision(local, &next_delay)) 743 return; 744 break; 745 case SCAN_SET_CHANNEL: 746 ieee80211_scan_state_set_channel(local, &next_delay); 747 break; 748 case SCAN_SEND_PROBE: 749 ieee80211_scan_state_send_probe(local, &next_delay); 750 break; 751 case SCAN_LEAVE_OPER_CHANNEL: 752 ieee80211_scan_state_leave_oper_channel(local, &next_delay); 753 break; 754 case SCAN_ENTER_OPER_CHANNEL: 755 ieee80211_scan_state_enter_oper_channel(local, &next_delay); 756 break; 757 } 758 } while (next_delay == 0); 759 760 ieee80211_queue_delayed_work(&local->hw, &local->scan_work, next_delay); 761 } 762 763 int ieee80211_request_scan(struct ieee80211_sub_if_data *sdata, 764 struct cfg80211_scan_request *req) 765 { 766 int res; 767 768 mutex_lock(&sdata->local->scan_mtx); 769 res = __ieee80211_start_scan(sdata, req); 770 mutex_unlock(&sdata->local->scan_mtx); 771 772 return res; 773 } 774 775 int ieee80211_request_internal_scan(struct ieee80211_sub_if_data *sdata, 776 const u8 *ssid, u8 ssid_len) 777 { 778 struct ieee80211_local *local = sdata->local; 779 int ret = -EBUSY; 780 781 mutex_lock(&local->scan_mtx); 782 783 /* busy scanning */ 784 if (local->scan_req) 785 goto unlock; 786 787 memcpy(local->int_scan_req->ssids[0].ssid, ssid, IEEE80211_MAX_SSID_LEN); 788 local->int_scan_req->ssids[0].ssid_len = ssid_len; 789 790 ret = __ieee80211_start_scan(sdata, sdata->local->int_scan_req); 791 unlock: 792 mutex_unlock(&local->scan_mtx); 793 return ret; 794 } 795 796 void ieee80211_scan_cancel(struct ieee80211_local *local) 797 { 798 bool abortscan; 799 800 cancel_delayed_work_sync(&local->scan_work); 801 802 /* 803 * Only call this function when a scan can't be 804 * queued -- mostly at suspend under RTNL. 805 */ 806 mutex_lock(&local->scan_mtx); 807 abortscan = test_bit(SCAN_SW_SCANNING, &local->scanning) || 808 (!local->scanning && local->scan_req); 809 mutex_unlock(&local->scan_mtx); 810 811 if (abortscan) 812 ieee80211_scan_completed(&local->hw, true); 813 } 814