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/if_arp.h> 16 #include <linux/etherdevice.h> 17 #include <linux/rtnetlink.h> 18 #include <linux/pm_qos.h> 19 #include <net/sch_generic.h> 20 #include <linux/slab.h> 21 #include <linux/export.h> 22 #include <net/mac80211.h> 23 24 #include "ieee80211_i.h" 25 #include "driver-ops.h" 26 #include "mesh.h" 27 28 #define IEEE80211_PROBE_DELAY (HZ / 33) 29 #define IEEE80211_CHANNEL_TIME (HZ / 33) 30 #define IEEE80211_PASSIVE_CHANNEL_TIME (HZ / 8) 31 32 static void ieee80211_rx_bss_free(struct cfg80211_bss *cbss) 33 { 34 struct ieee80211_bss *bss = (void *)cbss->priv; 35 36 kfree(bss_mesh_id(bss)); 37 kfree(bss_mesh_cfg(bss)); 38 } 39 40 void ieee80211_rx_bss_put(struct ieee80211_local *local, 41 struct ieee80211_bss *bss) 42 { 43 if (!bss) 44 return; 45 cfg80211_put_bss(container_of((void *)bss, struct cfg80211_bss, priv)); 46 } 47 48 static bool is_uapsd_supported(struct ieee802_11_elems *elems) 49 { 50 u8 qos_info; 51 52 if (elems->wmm_info && elems->wmm_info_len == 7 53 && elems->wmm_info[5] == 1) 54 qos_info = elems->wmm_info[6]; 55 else if (elems->wmm_param && elems->wmm_param_len == 24 56 && elems->wmm_param[5] == 1) 57 qos_info = elems->wmm_param[6]; 58 else 59 /* no valid wmm information or parameter element found */ 60 return false; 61 62 return qos_info & IEEE80211_WMM_IE_AP_QOSINFO_UAPSD; 63 } 64 65 struct ieee80211_bss * 66 ieee80211_bss_info_update(struct ieee80211_local *local, 67 struct ieee80211_rx_status *rx_status, 68 struct ieee80211_mgmt *mgmt, 69 size_t len, 70 struct ieee802_11_elems *elems, 71 struct ieee80211_channel *channel, 72 bool beacon) 73 { 74 struct cfg80211_bss *cbss; 75 struct ieee80211_bss *bss; 76 int clen, srlen; 77 s32 signal = 0; 78 79 if (local->hw.flags & IEEE80211_HW_SIGNAL_DBM) 80 signal = rx_status->signal * 100; 81 else if (local->hw.flags & IEEE80211_HW_SIGNAL_UNSPEC) 82 signal = (rx_status->signal * 100) / local->hw.max_signal; 83 84 cbss = cfg80211_inform_bss_frame(local->hw.wiphy, channel, 85 mgmt, len, signal, GFP_ATOMIC); 86 if (!cbss) 87 return NULL; 88 89 cbss->free_priv = ieee80211_rx_bss_free; 90 bss = (void *)cbss->priv; 91 92 bss->device_ts = rx_status->device_timestamp; 93 94 if (elems->parse_error) { 95 if (beacon) 96 bss->corrupt_data |= IEEE80211_BSS_CORRUPT_BEACON; 97 else 98 bss->corrupt_data |= IEEE80211_BSS_CORRUPT_PROBE_RESP; 99 } else { 100 if (beacon) 101 bss->corrupt_data &= ~IEEE80211_BSS_CORRUPT_BEACON; 102 else 103 bss->corrupt_data &= ~IEEE80211_BSS_CORRUPT_PROBE_RESP; 104 } 105 106 /* save the ERP value so that it is available at association time */ 107 if (elems->erp_info && elems->erp_info_len >= 1 && 108 (!elems->parse_error || 109 !(bss->valid_data & IEEE80211_BSS_VALID_ERP))) { 110 bss->erp_value = elems->erp_info[0]; 111 bss->has_erp_value = true; 112 if (!elems->parse_error) 113 bss->valid_data |= IEEE80211_BSS_VALID_ERP; 114 } 115 116 /* replace old supported rates if we get new values */ 117 if (!elems->parse_error || 118 !(bss->valid_data & IEEE80211_BSS_VALID_RATES)) { 119 srlen = 0; 120 if (elems->supp_rates) { 121 clen = IEEE80211_MAX_SUPP_RATES; 122 if (clen > elems->supp_rates_len) 123 clen = elems->supp_rates_len; 124 memcpy(bss->supp_rates, elems->supp_rates, clen); 125 srlen += clen; 126 } 127 if (elems->ext_supp_rates) { 128 clen = IEEE80211_MAX_SUPP_RATES - srlen; 129 if (clen > elems->ext_supp_rates_len) 130 clen = elems->ext_supp_rates_len; 131 memcpy(bss->supp_rates + srlen, elems->ext_supp_rates, 132 clen); 133 srlen += clen; 134 } 135 if (srlen) { 136 bss->supp_rates_len = srlen; 137 if (!elems->parse_error) 138 bss->valid_data |= IEEE80211_BSS_VALID_RATES; 139 } 140 } 141 142 if (!elems->parse_error || 143 !(bss->valid_data & IEEE80211_BSS_VALID_WMM)) { 144 bss->wmm_used = elems->wmm_param || elems->wmm_info; 145 bss->uapsd_supported = is_uapsd_supported(elems); 146 if (!elems->parse_error) 147 bss->valid_data |= IEEE80211_BSS_VALID_WMM; 148 } 149 150 if (!beacon) 151 bss->last_probe_resp = jiffies; 152 153 return bss; 154 } 155 156 void ieee80211_scan_rx(struct ieee80211_local *local, struct sk_buff *skb) 157 { 158 struct ieee80211_rx_status *rx_status = IEEE80211_SKB_RXCB(skb); 159 struct ieee80211_sub_if_data *sdata1, *sdata2; 160 struct ieee80211_mgmt *mgmt = (void *)skb->data; 161 struct ieee80211_bss *bss; 162 u8 *elements; 163 struct ieee80211_channel *channel; 164 size_t baselen; 165 bool beacon; 166 struct ieee802_11_elems elems; 167 168 if (skb->len < 24 || 169 (!ieee80211_is_probe_resp(mgmt->frame_control) && 170 !ieee80211_is_beacon(mgmt->frame_control))) 171 return; 172 173 sdata1 = rcu_dereference(local->scan_sdata); 174 sdata2 = rcu_dereference(local->sched_scan_sdata); 175 176 if (likely(!sdata1 && !sdata2)) 177 return; 178 179 if (ieee80211_is_probe_resp(mgmt->frame_control)) { 180 /* ignore ProbeResp to foreign address */ 181 if ((!sdata1 || !ether_addr_equal(mgmt->da, sdata1->vif.addr)) && 182 (!sdata2 || !ether_addr_equal(mgmt->da, sdata2->vif.addr))) 183 return; 184 185 elements = mgmt->u.probe_resp.variable; 186 baselen = offsetof(struct ieee80211_mgmt, u.probe_resp.variable); 187 beacon = false; 188 } else { 189 baselen = offsetof(struct ieee80211_mgmt, u.beacon.variable); 190 elements = mgmt->u.beacon.variable; 191 beacon = true; 192 } 193 194 if (baselen > skb->len) 195 return; 196 197 ieee802_11_parse_elems(elements, skb->len - baselen, &elems); 198 199 channel = ieee80211_get_channel(local->hw.wiphy, rx_status->freq); 200 201 if (!channel || channel->flags & IEEE80211_CHAN_DISABLED) 202 return; 203 204 bss = ieee80211_bss_info_update(local, rx_status, 205 mgmt, skb->len, &elems, 206 channel, beacon); 207 if (bss) 208 ieee80211_rx_bss_put(local, bss); 209 } 210 211 /* return false if no more work */ 212 static bool ieee80211_prep_hw_scan(struct ieee80211_local *local) 213 { 214 struct cfg80211_scan_request *req = local->scan_req; 215 enum ieee80211_band band; 216 int i, ielen, n_chans; 217 218 do { 219 if (local->hw_scan_band == IEEE80211_NUM_BANDS) 220 return false; 221 222 band = local->hw_scan_band; 223 n_chans = 0; 224 for (i = 0; i < req->n_channels; i++) { 225 if (req->channels[i]->band == band) { 226 local->hw_scan_req->channels[n_chans] = 227 req->channels[i]; 228 n_chans++; 229 } 230 } 231 232 local->hw_scan_band++; 233 } while (!n_chans); 234 235 local->hw_scan_req->n_channels = n_chans; 236 237 ielen = ieee80211_build_preq_ies(local, (u8 *)local->hw_scan_req->ie, 238 local->hw_scan_ies_bufsize, 239 req->ie, req->ie_len, band, 240 req->rates[band], 0); 241 local->hw_scan_req->ie_len = ielen; 242 local->hw_scan_req->no_cck = req->no_cck; 243 244 return true; 245 } 246 247 static void __ieee80211_scan_completed(struct ieee80211_hw *hw, bool aborted, 248 bool was_hw_scan) 249 { 250 struct ieee80211_local *local = hw_to_local(hw); 251 252 lockdep_assert_held(&local->mtx); 253 254 /* 255 * It's ok to abort a not-yet-running scan (that 256 * we have one at all will be verified by checking 257 * local->scan_req next), but not to complete it 258 * successfully. 259 */ 260 if (WARN_ON(!local->scanning && !aborted)) 261 aborted = true; 262 263 if (WARN_ON(!local->scan_req)) 264 return; 265 266 if (was_hw_scan && !aborted && ieee80211_prep_hw_scan(local)) { 267 int rc; 268 269 rc = drv_hw_scan(local, 270 rcu_dereference_protected(local->scan_sdata, 271 lockdep_is_held(&local->mtx)), 272 local->hw_scan_req); 273 274 if (rc == 0) 275 return; 276 } 277 278 kfree(local->hw_scan_req); 279 local->hw_scan_req = NULL; 280 281 if (local->scan_req != local->int_scan_req) 282 cfg80211_scan_done(local->scan_req, aborted); 283 local->scan_req = NULL; 284 rcu_assign_pointer(local->scan_sdata, NULL); 285 286 local->scanning = 0; 287 local->scan_channel = NULL; 288 289 /* Set power back to normal operating levels. */ 290 ieee80211_hw_config(local, 0); 291 292 if (!was_hw_scan) { 293 ieee80211_configure_filter(local); 294 drv_sw_scan_complete(local); 295 ieee80211_offchannel_return(local); 296 } 297 298 ieee80211_recalc_idle(local); 299 300 ieee80211_mlme_notify_scan_completed(local); 301 ieee80211_ibss_notify_scan_completed(local); 302 ieee80211_mesh_notify_scan_completed(local); 303 ieee80211_start_next_roc(local); 304 } 305 306 void ieee80211_scan_completed(struct ieee80211_hw *hw, bool aborted) 307 { 308 struct ieee80211_local *local = hw_to_local(hw); 309 310 trace_api_scan_completed(local, aborted); 311 312 set_bit(SCAN_COMPLETED, &local->scanning); 313 if (aborted) 314 set_bit(SCAN_ABORTED, &local->scanning); 315 ieee80211_queue_delayed_work(&local->hw, &local->scan_work, 0); 316 } 317 EXPORT_SYMBOL(ieee80211_scan_completed); 318 319 static int ieee80211_start_sw_scan(struct ieee80211_local *local) 320 { 321 /* Software scan is not supported in multi-channel cases */ 322 if (local->use_chanctx) 323 return -EOPNOTSUPP; 324 325 /* 326 * Hardware/driver doesn't support hw_scan, so use software 327 * scanning instead. First send a nullfunc frame with power save 328 * bit on so that AP will buffer the frames for us while we are not 329 * listening, then send probe requests to each channel and wait for 330 * the responses. After all channels are scanned, tune back to the 331 * original channel and send a nullfunc frame with power save bit 332 * off to trigger the AP to send us all the buffered frames. 333 * 334 * Note that while local->sw_scanning is true everything else but 335 * nullfunc frames and probe requests will be dropped in 336 * ieee80211_tx_h_check_assoc(). 337 */ 338 drv_sw_scan_start(local); 339 340 local->leave_oper_channel_time = jiffies; 341 local->next_scan_state = SCAN_DECISION; 342 local->scan_channel_idx = 0; 343 344 ieee80211_offchannel_stop_vifs(local); 345 346 ieee80211_configure_filter(local); 347 348 /* We need to set power level at maximum rate for scanning. */ 349 ieee80211_hw_config(local, 0); 350 351 ieee80211_queue_delayed_work(&local->hw, 352 &local->scan_work, 0); 353 354 return 0; 355 } 356 357 static bool ieee80211_can_scan(struct ieee80211_local *local, 358 struct ieee80211_sub_if_data *sdata) 359 { 360 if (!list_empty(&local->roc_list)) 361 return false; 362 363 if (sdata->vif.type == NL80211_IFTYPE_STATION && 364 sdata->u.mgd.flags & (IEEE80211_STA_BEACON_POLL | 365 IEEE80211_STA_CONNECTION_POLL)) 366 return false; 367 368 return true; 369 } 370 371 void ieee80211_run_deferred_scan(struct ieee80211_local *local) 372 { 373 lockdep_assert_held(&local->mtx); 374 375 if (!local->scan_req || local->scanning) 376 return; 377 378 if (!ieee80211_can_scan(local, 379 rcu_dereference_protected( 380 local->scan_sdata, 381 lockdep_is_held(&local->mtx)))) 382 return; 383 384 ieee80211_queue_delayed_work(&local->hw, &local->scan_work, 385 round_jiffies_relative(0)); 386 } 387 388 static void ieee80211_scan_state_send_probe(struct ieee80211_local *local, 389 unsigned long *next_delay) 390 { 391 int i; 392 struct ieee80211_sub_if_data *sdata; 393 enum ieee80211_band band = local->hw.conf.channel->band; 394 395 sdata = rcu_dereference_protected(local->scan_sdata, 396 lockdep_is_held(&local->mtx)); 397 398 for (i = 0; i < local->scan_req->n_ssids; i++) 399 ieee80211_send_probe_req( 400 sdata, NULL, 401 local->scan_req->ssids[i].ssid, 402 local->scan_req->ssids[i].ssid_len, 403 local->scan_req->ie, local->scan_req->ie_len, 404 local->scan_req->rates[band], false, 405 local->scan_req->no_cck, 406 local->hw.conf.channel, true); 407 408 /* 409 * After sending probe requests, wait for probe responses 410 * on the channel. 411 */ 412 *next_delay = IEEE80211_CHANNEL_TIME; 413 local->next_scan_state = SCAN_DECISION; 414 } 415 416 static int __ieee80211_start_scan(struct ieee80211_sub_if_data *sdata, 417 struct cfg80211_scan_request *req) 418 { 419 struct ieee80211_local *local = sdata->local; 420 int rc; 421 422 lockdep_assert_held(&local->mtx); 423 424 if (local->scan_req) 425 return -EBUSY; 426 427 if (!ieee80211_can_scan(local, sdata)) { 428 /* wait for the work to finish/time out */ 429 local->scan_req = req; 430 rcu_assign_pointer(local->scan_sdata, sdata); 431 return 0; 432 } 433 434 if (local->ops->hw_scan) { 435 u8 *ies; 436 437 local->hw_scan_ies_bufsize = 2 + IEEE80211_MAX_SSID_LEN + 438 local->scan_ies_len + 439 req->ie_len; 440 local->hw_scan_req = kmalloc( 441 sizeof(*local->hw_scan_req) + 442 req->n_channels * sizeof(req->channels[0]) + 443 local->hw_scan_ies_bufsize, GFP_KERNEL); 444 if (!local->hw_scan_req) 445 return -ENOMEM; 446 447 local->hw_scan_req->ssids = req->ssids; 448 local->hw_scan_req->n_ssids = req->n_ssids; 449 ies = (u8 *)local->hw_scan_req + 450 sizeof(*local->hw_scan_req) + 451 req->n_channels * sizeof(req->channels[0]); 452 local->hw_scan_req->ie = ies; 453 local->hw_scan_req->flags = req->flags; 454 455 local->hw_scan_band = 0; 456 457 /* 458 * After allocating local->hw_scan_req, we must 459 * go through until ieee80211_prep_hw_scan(), so 460 * anything that might be changed here and leave 461 * this function early must not go after this 462 * allocation. 463 */ 464 } 465 466 local->scan_req = req; 467 rcu_assign_pointer(local->scan_sdata, sdata); 468 469 if (local->ops->hw_scan) { 470 __set_bit(SCAN_HW_SCANNING, &local->scanning); 471 } else if ((req->n_channels == 1) && 472 (req->channels[0] == local->_oper_channel)) { 473 /* 474 * If we are scanning only on the operating channel 475 * then we do not need to stop normal activities 476 */ 477 unsigned long next_delay; 478 479 __set_bit(SCAN_ONCHANNEL_SCANNING, &local->scanning); 480 481 ieee80211_recalc_idle(local); 482 483 /* Notify driver scan is starting, keep order of operations 484 * same as normal software scan, in case that matters. */ 485 drv_sw_scan_start(local); 486 487 ieee80211_configure_filter(local); /* accept probe-responses */ 488 489 /* We need to ensure power level is at max for scanning. */ 490 ieee80211_hw_config(local, 0); 491 492 if ((req->channels[0]->flags & 493 IEEE80211_CHAN_PASSIVE_SCAN) || 494 !local->scan_req->n_ssids) { 495 next_delay = IEEE80211_PASSIVE_CHANNEL_TIME; 496 } else { 497 ieee80211_scan_state_send_probe(local, &next_delay); 498 next_delay = IEEE80211_CHANNEL_TIME; 499 } 500 501 /* Now, just wait a bit and we are all done! */ 502 ieee80211_queue_delayed_work(&local->hw, &local->scan_work, 503 next_delay); 504 return 0; 505 } else { 506 /* Do normal software scan */ 507 __set_bit(SCAN_SW_SCANNING, &local->scanning); 508 } 509 510 ieee80211_recalc_idle(local); 511 512 if (local->ops->hw_scan) { 513 WARN_ON(!ieee80211_prep_hw_scan(local)); 514 rc = drv_hw_scan(local, sdata, local->hw_scan_req); 515 } else 516 rc = ieee80211_start_sw_scan(local); 517 518 if (rc) { 519 kfree(local->hw_scan_req); 520 local->hw_scan_req = NULL; 521 local->scanning = 0; 522 523 ieee80211_recalc_idle(local); 524 525 local->scan_req = NULL; 526 rcu_assign_pointer(local->scan_sdata, NULL); 527 } 528 529 return rc; 530 } 531 532 static unsigned long 533 ieee80211_scan_get_channel_time(struct ieee80211_channel *chan) 534 { 535 /* 536 * TODO: channel switching also consumes quite some time, 537 * add that delay as well to get a better estimation 538 */ 539 if (chan->flags & IEEE80211_CHAN_PASSIVE_SCAN) 540 return IEEE80211_PASSIVE_CHANNEL_TIME; 541 return IEEE80211_PROBE_DELAY + IEEE80211_CHANNEL_TIME; 542 } 543 544 static void ieee80211_scan_state_decision(struct ieee80211_local *local, 545 unsigned long *next_delay) 546 { 547 bool associated = false; 548 bool tx_empty = true; 549 bool bad_latency; 550 bool listen_int_exceeded; 551 unsigned long min_beacon_int = 0; 552 struct ieee80211_sub_if_data *sdata; 553 struct ieee80211_channel *next_chan; 554 enum mac80211_scan_state next_scan_state; 555 556 /* 557 * check if at least one STA interface is associated, 558 * check if at least one STA interface has pending tx frames 559 * and grab the lowest used beacon interval 560 */ 561 mutex_lock(&local->iflist_mtx); 562 list_for_each_entry(sdata, &local->interfaces, list) { 563 if (!ieee80211_sdata_running(sdata)) 564 continue; 565 566 if (sdata->vif.type == NL80211_IFTYPE_STATION) { 567 if (sdata->u.mgd.associated) { 568 associated = true; 569 570 if (sdata->vif.bss_conf.beacon_int < 571 min_beacon_int || min_beacon_int == 0) 572 min_beacon_int = 573 sdata->vif.bss_conf.beacon_int; 574 575 if (!qdisc_all_tx_empty(sdata->dev)) { 576 tx_empty = false; 577 break; 578 } 579 } 580 } 581 } 582 mutex_unlock(&local->iflist_mtx); 583 584 next_chan = local->scan_req->channels[local->scan_channel_idx]; 585 586 /* 587 * we're currently scanning a different channel, let's 588 * see if we can scan another channel without interfering 589 * with the current traffic situation. 590 * 591 * Since we don't know if the AP has pending frames for us 592 * we can only check for our tx queues and use the current 593 * pm_qos requirements for rx. Hence, if no tx traffic occurs 594 * at all we will scan as many channels in a row as the pm_qos 595 * latency allows us to. Additionally we also check for the 596 * currently negotiated listen interval to prevent losing 597 * frames unnecessarily. 598 * 599 * Otherwise switch back to the operating channel. 600 */ 601 602 bad_latency = time_after(jiffies + 603 ieee80211_scan_get_channel_time(next_chan), 604 local->leave_oper_channel_time + 605 usecs_to_jiffies(pm_qos_request(PM_QOS_NETWORK_LATENCY))); 606 607 listen_int_exceeded = time_after(jiffies + 608 ieee80211_scan_get_channel_time(next_chan), 609 local->leave_oper_channel_time + 610 usecs_to_jiffies(min_beacon_int * 1024) * 611 local->hw.conf.listen_interval); 612 613 if (associated && !tx_empty) { 614 if (local->scan_req->flags & NL80211_SCAN_FLAG_LOW_PRIORITY) 615 next_scan_state = SCAN_ABORT; 616 else 617 next_scan_state = SCAN_SUSPEND; 618 } else if (associated && (bad_latency || listen_int_exceeded)) { 619 next_scan_state = SCAN_SUSPEND; 620 } else { 621 next_scan_state = SCAN_SET_CHANNEL; 622 } 623 624 local->next_scan_state = next_scan_state; 625 626 *next_delay = 0; 627 } 628 629 static void ieee80211_scan_state_set_channel(struct ieee80211_local *local, 630 unsigned long *next_delay) 631 { 632 int skip; 633 struct ieee80211_channel *chan; 634 635 skip = 0; 636 chan = local->scan_req->channels[local->scan_channel_idx]; 637 638 local->scan_channel = chan; 639 640 if (ieee80211_hw_config(local, IEEE80211_CONF_CHANGE_CHANNEL)) 641 skip = 1; 642 643 /* advance state machine to next channel/band */ 644 local->scan_channel_idx++; 645 646 if (skip) { 647 /* if we skip this channel return to the decision state */ 648 local->next_scan_state = SCAN_DECISION; 649 return; 650 } 651 652 /* 653 * Probe delay is used to update the NAV, cf. 11.1.3.2.2 654 * (which unfortunately doesn't say _why_ step a) is done, 655 * but it waits for the probe delay or until a frame is 656 * received - and the received frame would update the NAV). 657 * For now, we do not support waiting until a frame is 658 * received. 659 * 660 * In any case, it is not necessary for a passive scan. 661 */ 662 if (chan->flags & IEEE80211_CHAN_PASSIVE_SCAN || 663 !local->scan_req->n_ssids) { 664 *next_delay = IEEE80211_PASSIVE_CHANNEL_TIME; 665 local->next_scan_state = SCAN_DECISION; 666 return; 667 } 668 669 /* active scan, send probes */ 670 *next_delay = IEEE80211_PROBE_DELAY; 671 local->next_scan_state = SCAN_SEND_PROBE; 672 } 673 674 static void ieee80211_scan_state_suspend(struct ieee80211_local *local, 675 unsigned long *next_delay) 676 { 677 /* switch back to the operating channel */ 678 local->scan_channel = NULL; 679 ieee80211_hw_config(local, IEEE80211_CONF_CHANGE_CHANNEL); 680 681 /* disable PS */ 682 ieee80211_offchannel_return(local); 683 684 *next_delay = HZ / 5; 685 /* afterwards, resume scan & go to next channel */ 686 local->next_scan_state = SCAN_RESUME; 687 } 688 689 static void ieee80211_scan_state_resume(struct ieee80211_local *local, 690 unsigned long *next_delay) 691 { 692 ieee80211_offchannel_stop_vifs(local); 693 694 if (local->ops->flush) { 695 drv_flush(local, false); 696 *next_delay = 0; 697 } else 698 *next_delay = HZ / 10; 699 700 /* remember when we left the operating channel */ 701 local->leave_oper_channel_time = jiffies; 702 703 /* advance to the next channel to be scanned */ 704 local->next_scan_state = SCAN_SET_CHANNEL; 705 } 706 707 void ieee80211_scan_work(struct work_struct *work) 708 { 709 struct ieee80211_local *local = 710 container_of(work, struct ieee80211_local, scan_work.work); 711 struct ieee80211_sub_if_data *sdata; 712 unsigned long next_delay = 0; 713 bool aborted, hw_scan; 714 715 mutex_lock(&local->mtx); 716 717 sdata = rcu_dereference_protected(local->scan_sdata, 718 lockdep_is_held(&local->mtx)); 719 720 /* When scanning on-channel, the first-callback means completed. */ 721 if (test_bit(SCAN_ONCHANNEL_SCANNING, &local->scanning)) { 722 aborted = test_and_clear_bit(SCAN_ABORTED, &local->scanning); 723 goto out_complete; 724 } 725 726 if (test_and_clear_bit(SCAN_COMPLETED, &local->scanning)) { 727 aborted = test_and_clear_bit(SCAN_ABORTED, &local->scanning); 728 goto out_complete; 729 } 730 731 if (!sdata || !local->scan_req) 732 goto out; 733 734 if (local->scan_req && !local->scanning) { 735 struct cfg80211_scan_request *req = local->scan_req; 736 int rc; 737 738 local->scan_req = NULL; 739 rcu_assign_pointer(local->scan_sdata, NULL); 740 741 rc = __ieee80211_start_scan(sdata, req); 742 if (rc) { 743 /* need to complete scan in cfg80211 */ 744 local->scan_req = req; 745 aborted = true; 746 goto out_complete; 747 } else 748 goto out; 749 } 750 751 /* 752 * Avoid re-scheduling when the sdata is going away. 753 */ 754 if (!ieee80211_sdata_running(sdata)) { 755 aborted = true; 756 goto out_complete; 757 } 758 759 /* 760 * as long as no delay is required advance immediately 761 * without scheduling a new work 762 */ 763 do { 764 if (!ieee80211_sdata_running(sdata)) { 765 aborted = true; 766 goto out_complete; 767 } 768 769 switch (local->next_scan_state) { 770 case SCAN_DECISION: 771 /* if no more bands/channels left, complete scan */ 772 if (local->scan_channel_idx >= local->scan_req->n_channels) { 773 aborted = false; 774 goto out_complete; 775 } 776 ieee80211_scan_state_decision(local, &next_delay); 777 break; 778 case SCAN_SET_CHANNEL: 779 ieee80211_scan_state_set_channel(local, &next_delay); 780 break; 781 case SCAN_SEND_PROBE: 782 ieee80211_scan_state_send_probe(local, &next_delay); 783 break; 784 case SCAN_SUSPEND: 785 ieee80211_scan_state_suspend(local, &next_delay); 786 break; 787 case SCAN_RESUME: 788 ieee80211_scan_state_resume(local, &next_delay); 789 break; 790 case SCAN_ABORT: 791 aborted = true; 792 goto out_complete; 793 } 794 } while (next_delay == 0); 795 796 ieee80211_queue_delayed_work(&local->hw, &local->scan_work, next_delay); 797 goto out; 798 799 out_complete: 800 hw_scan = test_bit(SCAN_HW_SCANNING, &local->scanning); 801 __ieee80211_scan_completed(&local->hw, aborted, hw_scan); 802 out: 803 mutex_unlock(&local->mtx); 804 } 805 806 int ieee80211_request_scan(struct ieee80211_sub_if_data *sdata, 807 struct cfg80211_scan_request *req) 808 { 809 int res; 810 811 mutex_lock(&sdata->local->mtx); 812 res = __ieee80211_start_scan(sdata, req); 813 mutex_unlock(&sdata->local->mtx); 814 815 return res; 816 } 817 818 int ieee80211_request_ibss_scan(struct ieee80211_sub_if_data *sdata, 819 const u8 *ssid, u8 ssid_len, 820 struct ieee80211_channel *chan) 821 { 822 struct ieee80211_local *local = sdata->local; 823 int ret = -EBUSY; 824 enum ieee80211_band band; 825 826 mutex_lock(&local->mtx); 827 828 /* busy scanning */ 829 if (local->scan_req) 830 goto unlock; 831 832 /* fill internal scan request */ 833 if (!chan) { 834 int i, max_n; 835 int n_ch = 0; 836 837 for (band = 0; band < IEEE80211_NUM_BANDS; band++) { 838 if (!local->hw.wiphy->bands[band]) 839 continue; 840 841 max_n = local->hw.wiphy->bands[band]->n_channels; 842 for (i = 0; i < max_n; i++) { 843 struct ieee80211_channel *tmp_ch = 844 &local->hw.wiphy->bands[band]->channels[i]; 845 846 if (tmp_ch->flags & (IEEE80211_CHAN_NO_IBSS | 847 IEEE80211_CHAN_DISABLED)) 848 continue; 849 850 local->int_scan_req->channels[n_ch] = tmp_ch; 851 n_ch++; 852 } 853 } 854 855 if (WARN_ON_ONCE(n_ch == 0)) 856 goto unlock; 857 858 local->int_scan_req->n_channels = n_ch; 859 } else { 860 if (WARN_ON_ONCE(chan->flags & (IEEE80211_CHAN_NO_IBSS | 861 IEEE80211_CHAN_DISABLED))) 862 goto unlock; 863 864 local->int_scan_req->channels[0] = chan; 865 local->int_scan_req->n_channels = 1; 866 } 867 868 local->int_scan_req->ssids = &local->scan_ssid; 869 local->int_scan_req->n_ssids = 1; 870 memcpy(local->int_scan_req->ssids[0].ssid, ssid, IEEE80211_MAX_SSID_LEN); 871 local->int_scan_req->ssids[0].ssid_len = ssid_len; 872 873 ret = __ieee80211_start_scan(sdata, sdata->local->int_scan_req); 874 unlock: 875 mutex_unlock(&local->mtx); 876 return ret; 877 } 878 879 /* 880 * Only call this function when a scan can't be queued -- under RTNL. 881 */ 882 void ieee80211_scan_cancel(struct ieee80211_local *local) 883 { 884 /* 885 * We are canceling software scan, or deferred scan that was not 886 * yet really started (see __ieee80211_start_scan ). 887 * 888 * Regarding hardware scan: 889 * - we can not call __ieee80211_scan_completed() as when 890 * SCAN_HW_SCANNING bit is set this function change 891 * local->hw_scan_req to operate on 5G band, what race with 892 * driver which can use local->hw_scan_req 893 * 894 * - we can not cancel scan_work since driver can schedule it 895 * by ieee80211_scan_completed(..., true) to finish scan 896 * 897 * Hence we only call the cancel_hw_scan() callback, but the low-level 898 * driver is still responsible for calling ieee80211_scan_completed() 899 * after the scan was completed/aborted. 900 */ 901 902 mutex_lock(&local->mtx); 903 if (!local->scan_req) 904 goto out; 905 906 if (test_bit(SCAN_HW_SCANNING, &local->scanning)) { 907 if (local->ops->cancel_hw_scan) 908 drv_cancel_hw_scan(local, 909 rcu_dereference_protected(local->scan_sdata, 910 lockdep_is_held(&local->mtx))); 911 goto out; 912 } 913 914 /* 915 * If the work is currently running, it must be blocked on 916 * the mutex, but we'll set scan_sdata = NULL and it'll 917 * simply exit once it acquires the mutex. 918 */ 919 cancel_delayed_work(&local->scan_work); 920 /* and clean up */ 921 __ieee80211_scan_completed(&local->hw, true, false); 922 out: 923 mutex_unlock(&local->mtx); 924 } 925 926 int ieee80211_request_sched_scan_start(struct ieee80211_sub_if_data *sdata, 927 struct cfg80211_sched_scan_request *req) 928 { 929 struct ieee80211_local *local = sdata->local; 930 struct ieee80211_sched_scan_ies sched_scan_ies = {}; 931 int ret, i, iebufsz; 932 933 iebufsz = 2 + IEEE80211_MAX_SSID_LEN + 934 local->scan_ies_len + req->ie_len; 935 936 mutex_lock(&local->mtx); 937 938 if (rcu_access_pointer(local->sched_scan_sdata)) { 939 ret = -EBUSY; 940 goto out; 941 } 942 943 if (!local->ops->sched_scan_start) { 944 ret = -ENOTSUPP; 945 goto out; 946 } 947 948 for (i = 0; i < IEEE80211_NUM_BANDS; i++) { 949 if (!local->hw.wiphy->bands[i]) 950 continue; 951 952 sched_scan_ies.ie[i] = kzalloc(iebufsz, GFP_KERNEL); 953 if (!sched_scan_ies.ie[i]) { 954 ret = -ENOMEM; 955 goto out_free; 956 } 957 958 sched_scan_ies.len[i] = 959 ieee80211_build_preq_ies(local, sched_scan_ies.ie[i], 960 iebufsz, req->ie, req->ie_len, 961 i, (u32) -1, 0); 962 } 963 964 ret = drv_sched_scan_start(local, sdata, req, &sched_scan_ies); 965 if (ret == 0) 966 rcu_assign_pointer(local->sched_scan_sdata, sdata); 967 968 out_free: 969 while (i > 0) 970 kfree(sched_scan_ies.ie[--i]); 971 out: 972 mutex_unlock(&local->mtx); 973 return ret; 974 } 975 976 int ieee80211_request_sched_scan_stop(struct ieee80211_sub_if_data *sdata) 977 { 978 struct ieee80211_local *local = sdata->local; 979 int ret = 0; 980 981 mutex_lock(&local->mtx); 982 983 if (!local->ops->sched_scan_stop) { 984 ret = -ENOTSUPP; 985 goto out; 986 } 987 988 if (rcu_access_pointer(local->sched_scan_sdata)) 989 drv_sched_scan_stop(local, sdata); 990 991 out: 992 mutex_unlock(&local->mtx); 993 994 return ret; 995 } 996 997 void ieee80211_sched_scan_results(struct ieee80211_hw *hw) 998 { 999 struct ieee80211_local *local = hw_to_local(hw); 1000 1001 trace_api_sched_scan_results(local); 1002 1003 cfg80211_sched_scan_results(hw->wiphy); 1004 } 1005 EXPORT_SYMBOL(ieee80211_sched_scan_results); 1006 1007 void ieee80211_sched_scan_stopped_work(struct work_struct *work) 1008 { 1009 struct ieee80211_local *local = 1010 container_of(work, struct ieee80211_local, 1011 sched_scan_stopped_work); 1012 1013 mutex_lock(&local->mtx); 1014 1015 if (!rcu_access_pointer(local->sched_scan_sdata)) { 1016 mutex_unlock(&local->mtx); 1017 return; 1018 } 1019 1020 rcu_assign_pointer(local->sched_scan_sdata, NULL); 1021 1022 mutex_unlock(&local->mtx); 1023 1024 cfg80211_sched_scan_stopped(local->hw.wiphy); 1025 } 1026 1027 void ieee80211_sched_scan_stopped(struct ieee80211_hw *hw) 1028 { 1029 struct ieee80211_local *local = hw_to_local(hw); 1030 1031 trace_api_sched_scan_stopped(local); 1032 1033 ieee80211_queue_work(&local->hw, &local->sched_scan_stopped_work); 1034 } 1035 EXPORT_SYMBOL(ieee80211_sched_scan_stopped); 1036