scan.c revision 0c2bef4621c5feb5bda9068c9964b2e9acf57017
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 / 9) 31 32void ieee80211_rx_bss_put(struct ieee80211_local *local, 33 struct ieee80211_bss *bss) 34{ 35 if (!bss) 36 return; 37 cfg80211_put_bss(local->hw.wiphy, 38 container_of((void *)bss, struct cfg80211_bss, priv)); 39} 40 41static bool is_uapsd_supported(struct ieee802_11_elems *elems) 42{ 43 u8 qos_info; 44 45 if (elems->wmm_info && elems->wmm_info_len == 7 46 && elems->wmm_info[5] == 1) 47 qos_info = elems->wmm_info[6]; 48 else if (elems->wmm_param && elems->wmm_param_len == 24 49 && elems->wmm_param[5] == 1) 50 qos_info = elems->wmm_param[6]; 51 else 52 /* no valid wmm information or parameter element found */ 53 return false; 54 55 return qos_info & IEEE80211_WMM_IE_AP_QOSINFO_UAPSD; 56} 57 58struct ieee80211_bss * 59ieee80211_bss_info_update(struct ieee80211_local *local, 60 struct ieee80211_rx_status *rx_status, 61 struct ieee80211_mgmt *mgmt, size_t len, 62 struct ieee802_11_elems *elems, 63 struct ieee80211_channel *channel) 64{ 65 bool beacon = ieee80211_is_beacon(mgmt->frame_control); 66 struct cfg80211_bss *cbss; 67 struct ieee80211_bss *bss; 68 int clen, srlen; 69 enum nl80211_bss_scan_width scan_width; 70 s32 signal = 0; 71 72 if (local->hw.flags & IEEE80211_HW_SIGNAL_DBM) 73 signal = rx_status->signal * 100; 74 else if (local->hw.flags & IEEE80211_HW_SIGNAL_UNSPEC) 75 signal = (rx_status->signal * 100) / local->hw.max_signal; 76 77 scan_width = NL80211_BSS_CHAN_WIDTH_20; 78 if (rx_status->flag & RX_FLAG_5MHZ) 79 scan_width = NL80211_BSS_CHAN_WIDTH_5; 80 if (rx_status->flag & RX_FLAG_10MHZ) 81 scan_width = NL80211_BSS_CHAN_WIDTH_10; 82 83 cbss = cfg80211_inform_bss_width_frame(local->hw.wiphy, channel, 84 scan_width, mgmt, len, signal, 85 GFP_ATOMIC); 86 if (!cbss) 87 return NULL; 88 89 bss = (void *)cbss->priv; 90 91 if (beacon) 92 bss->device_ts_beacon = rx_status->device_timestamp; 93 else 94 bss->device_ts_presp = rx_status->device_timestamp; 95 96 if (elems->parse_error) { 97 if (beacon) 98 bss->corrupt_data |= IEEE80211_BSS_CORRUPT_BEACON; 99 else 100 bss->corrupt_data |= IEEE80211_BSS_CORRUPT_PROBE_RESP; 101 } else { 102 if (beacon) 103 bss->corrupt_data &= ~IEEE80211_BSS_CORRUPT_BEACON; 104 else 105 bss->corrupt_data &= ~IEEE80211_BSS_CORRUPT_PROBE_RESP; 106 } 107 108 /* save the ERP value so that it is available at association time */ 109 if (elems->erp_info && (!elems->parse_error || 110 !(bss->valid_data & IEEE80211_BSS_VALID_ERP))) { 111 bss->erp_value = elems->erp_info[0]; 112 bss->has_erp_value = true; 113 if (!elems->parse_error) 114 bss->valid_data |= IEEE80211_BSS_VALID_ERP; 115 } 116 117 /* replace old supported rates if we get new values */ 118 if (!elems->parse_error || 119 !(bss->valid_data & IEEE80211_BSS_VALID_RATES)) { 120 srlen = 0; 121 if (elems->supp_rates) { 122 clen = IEEE80211_MAX_SUPP_RATES; 123 if (clen > elems->supp_rates_len) 124 clen = elems->supp_rates_len; 125 memcpy(bss->supp_rates, elems->supp_rates, clen); 126 srlen += clen; 127 } 128 if (elems->ext_supp_rates) { 129 clen = IEEE80211_MAX_SUPP_RATES - srlen; 130 if (clen > elems->ext_supp_rates_len) 131 clen = elems->ext_supp_rates_len; 132 memcpy(bss->supp_rates + srlen, elems->ext_supp_rates, 133 clen); 134 srlen += clen; 135 } 136 if (srlen) { 137 bss->supp_rates_len = srlen; 138 if (!elems->parse_error) 139 bss->valid_data |= IEEE80211_BSS_VALID_RATES; 140 } 141 } 142 143 if (!elems->parse_error || 144 !(bss->valid_data & IEEE80211_BSS_VALID_WMM)) { 145 bss->wmm_used = elems->wmm_param || elems->wmm_info; 146 bss->uapsd_supported = is_uapsd_supported(elems); 147 if (!elems->parse_error) 148 bss->valid_data |= IEEE80211_BSS_VALID_WMM; 149 } 150 151 if (beacon) { 152 struct ieee80211_supported_band *sband = 153 local->hw.wiphy->bands[rx_status->band]; 154 if (!(rx_status->flag & RX_FLAG_HT) && 155 !(rx_status->flag & RX_FLAG_VHT)) 156 bss->beacon_rate = 157 &sband->bitrates[rx_status->rate_idx]; 158 } 159 160 return bss; 161} 162 163void ieee80211_scan_rx(struct ieee80211_local *local, struct sk_buff *skb) 164{ 165 struct ieee80211_rx_status *rx_status = IEEE80211_SKB_RXCB(skb); 166 struct ieee80211_sub_if_data *sdata1, *sdata2; 167 struct ieee80211_mgmt *mgmt = (void *)skb->data; 168 struct ieee80211_bss *bss; 169 u8 *elements; 170 struct ieee80211_channel *channel; 171 size_t baselen; 172 struct ieee802_11_elems elems; 173 174 if (skb->len < 24 || 175 (!ieee80211_is_probe_resp(mgmt->frame_control) && 176 !ieee80211_is_beacon(mgmt->frame_control))) 177 return; 178 179 sdata1 = rcu_dereference(local->scan_sdata); 180 sdata2 = rcu_dereference(local->sched_scan_sdata); 181 182 if (likely(!sdata1 && !sdata2)) 183 return; 184 185 if (ieee80211_is_probe_resp(mgmt->frame_control)) { 186 /* ignore ProbeResp to foreign address */ 187 if ((!sdata1 || !ether_addr_equal(mgmt->da, sdata1->vif.addr)) && 188 (!sdata2 || !ether_addr_equal(mgmt->da, sdata2->vif.addr))) 189 return; 190 191 elements = mgmt->u.probe_resp.variable; 192 baselen = offsetof(struct ieee80211_mgmt, u.probe_resp.variable); 193 } else { 194 baselen = offsetof(struct ieee80211_mgmt, u.beacon.variable); 195 elements = mgmt->u.beacon.variable; 196 } 197 198 if (baselen > skb->len) 199 return; 200 201 ieee802_11_parse_elems(elements, skb->len - baselen, false, &elems); 202 203 channel = ieee80211_get_channel(local->hw.wiphy, rx_status->freq); 204 205 if (!channel || channel->flags & IEEE80211_CHAN_DISABLED) 206 return; 207 208 bss = ieee80211_bss_info_update(local, rx_status, 209 mgmt, skb->len, &elems, 210 channel); 211 if (bss) 212 ieee80211_rx_bss_put(local, bss); 213} 214 215static void 216ieee80211_prepare_scan_chandef(struct cfg80211_chan_def *chandef, 217 enum nl80211_bss_scan_width scan_width) 218{ 219 memset(chandef, 0, sizeof(*chandef)); 220 switch (scan_width) { 221 case NL80211_BSS_CHAN_WIDTH_5: 222 chandef->width = NL80211_CHAN_WIDTH_5; 223 break; 224 case NL80211_BSS_CHAN_WIDTH_10: 225 chandef->width = NL80211_CHAN_WIDTH_10; 226 break; 227 default: 228 chandef->width = NL80211_CHAN_WIDTH_20_NOHT; 229 break; 230 } 231} 232 233/* return false if no more work */ 234static bool ieee80211_prep_hw_scan(struct ieee80211_local *local) 235{ 236 struct cfg80211_scan_request *req = local->scan_req; 237 struct cfg80211_chan_def chandef; 238 enum ieee80211_band band; 239 int i, ielen, n_chans; 240 241 if (test_bit(SCAN_HW_CANCELLED, &local->scanning)) 242 return false; 243 244 do { 245 if (local->hw_scan_band == IEEE80211_NUM_BANDS) 246 return false; 247 248 band = local->hw_scan_band; 249 n_chans = 0; 250 for (i = 0; i < req->n_channels; i++) { 251 if (req->channels[i]->band == band) { 252 local->hw_scan_req->channels[n_chans] = 253 req->channels[i]; 254 n_chans++; 255 } 256 } 257 258 local->hw_scan_band++; 259 } while (!n_chans); 260 261 local->hw_scan_req->n_channels = n_chans; 262 ieee80211_prepare_scan_chandef(&chandef, req->scan_width); 263 264 ielen = ieee80211_build_preq_ies(local, (u8 *)local->hw_scan_req->ie, 265 local->hw_scan_ies_bufsize, 266 req->ie, req->ie_len, band, 267 req->rates[band], &chandef); 268 local->hw_scan_req->ie_len = ielen; 269 local->hw_scan_req->no_cck = req->no_cck; 270 271 return true; 272} 273 274static void __ieee80211_scan_completed(struct ieee80211_hw *hw, bool aborted) 275{ 276 struct ieee80211_local *local = hw_to_local(hw); 277 bool hw_scan = local->ops->hw_scan; 278 bool was_scanning = local->scanning; 279 280 lockdep_assert_held(&local->mtx); 281 282 /* 283 * It's ok to abort a not-yet-running scan (that 284 * we have one at all will be verified by checking 285 * local->scan_req next), but not to complete it 286 * successfully. 287 */ 288 if (WARN_ON(!local->scanning && !aborted)) 289 aborted = true; 290 291 if (WARN_ON(!local->scan_req)) 292 return; 293 294 if (hw_scan && !aborted && ieee80211_prep_hw_scan(local)) { 295 int rc; 296 297 rc = drv_hw_scan(local, 298 rcu_dereference_protected(local->scan_sdata, 299 lockdep_is_held(&local->mtx)), 300 local->hw_scan_req); 301 302 if (rc == 0) 303 return; 304 } 305 306 kfree(local->hw_scan_req); 307 local->hw_scan_req = NULL; 308 309 if (local->scan_req != local->int_scan_req) 310 cfg80211_scan_done(local->scan_req, aborted); 311 local->scan_req = NULL; 312 RCU_INIT_POINTER(local->scan_sdata, NULL); 313 314 local->scanning = 0; 315 local->scan_chandef.chan = NULL; 316 317 /* Set power back to normal operating levels. */ 318 ieee80211_hw_config(local, 0); 319 320 if (!hw_scan) { 321 ieee80211_configure_filter(local); 322 drv_sw_scan_complete(local); 323 ieee80211_offchannel_return(local); 324 } 325 326 ieee80211_recalc_idle(local); 327 328 ieee80211_mlme_notify_scan_completed(local); 329 ieee80211_ibss_notify_scan_completed(local); 330 ieee80211_mesh_notify_scan_completed(local); 331 if (was_scanning) 332 ieee80211_start_next_roc(local); 333} 334 335void ieee80211_scan_completed(struct ieee80211_hw *hw, bool aborted) 336{ 337 struct ieee80211_local *local = hw_to_local(hw); 338 339 trace_api_scan_completed(local, aborted); 340 341 set_bit(SCAN_COMPLETED, &local->scanning); 342 if (aborted) 343 set_bit(SCAN_ABORTED, &local->scanning); 344 ieee80211_queue_delayed_work(&local->hw, &local->scan_work, 0); 345} 346EXPORT_SYMBOL(ieee80211_scan_completed); 347 348static int ieee80211_start_sw_scan(struct ieee80211_local *local) 349{ 350 /* Software scan is not supported in multi-channel cases */ 351 if (local->use_chanctx) 352 return -EOPNOTSUPP; 353 354 /* 355 * Hardware/driver doesn't support hw_scan, so use software 356 * scanning instead. First send a nullfunc frame with power save 357 * bit on so that AP will buffer the frames for us while we are not 358 * listening, then send probe requests to each channel and wait for 359 * the responses. After all channels are scanned, tune back to the 360 * original channel and send a nullfunc frame with power save bit 361 * off to trigger the AP to send us all the buffered frames. 362 * 363 * Note that while local->sw_scanning is true everything else but 364 * nullfunc frames and probe requests will be dropped in 365 * ieee80211_tx_h_check_assoc(). 366 */ 367 drv_sw_scan_start(local); 368 369 local->leave_oper_channel_time = jiffies; 370 local->next_scan_state = SCAN_DECISION; 371 local->scan_channel_idx = 0; 372 373 ieee80211_offchannel_stop_vifs(local); 374 375 /* ensure nullfunc is transmitted before leaving operating channel */ 376 ieee80211_flush_queues(local, NULL); 377 378 ieee80211_configure_filter(local); 379 380 /* We need to set power level at maximum rate for scanning. */ 381 ieee80211_hw_config(local, 0); 382 383 ieee80211_queue_delayed_work(&local->hw, 384 &local->scan_work, 0); 385 386 return 0; 387} 388 389static bool ieee80211_can_scan(struct ieee80211_local *local, 390 struct ieee80211_sub_if_data *sdata) 391{ 392 if (local->radar_detect_enabled) 393 return false; 394 395 if (!list_empty(&local->roc_list)) 396 return false; 397 398 if (sdata->vif.type == NL80211_IFTYPE_STATION && 399 sdata->u.mgd.flags & IEEE80211_STA_CONNECTION_POLL) 400 return false; 401 402 return true; 403} 404 405void ieee80211_run_deferred_scan(struct ieee80211_local *local) 406{ 407 lockdep_assert_held(&local->mtx); 408 409 if (!local->scan_req || local->scanning) 410 return; 411 412 if (!ieee80211_can_scan(local, 413 rcu_dereference_protected( 414 local->scan_sdata, 415 lockdep_is_held(&local->mtx)))) 416 return; 417 418 ieee80211_queue_delayed_work(&local->hw, &local->scan_work, 419 round_jiffies_relative(0)); 420} 421 422static void ieee80211_scan_state_send_probe(struct ieee80211_local *local, 423 unsigned long *next_delay) 424{ 425 int i; 426 struct ieee80211_sub_if_data *sdata; 427 enum ieee80211_band band = local->hw.conf.chandef.chan->band; 428 u32 tx_flags; 429 430 tx_flags = IEEE80211_TX_INTFL_OFFCHAN_TX_OK; 431 if (local->scan_req->no_cck) 432 tx_flags |= IEEE80211_TX_CTL_NO_CCK_RATE; 433 434 sdata = rcu_dereference_protected(local->scan_sdata, 435 lockdep_is_held(&local->mtx)); 436 437 for (i = 0; i < local->scan_req->n_ssids; i++) 438 ieee80211_send_probe_req( 439 sdata, NULL, 440 local->scan_req->ssids[i].ssid, 441 local->scan_req->ssids[i].ssid_len, 442 local->scan_req->ie, local->scan_req->ie_len, 443 local->scan_req->rates[band], false, 444 tx_flags, local->hw.conf.chandef.chan, true); 445 446 /* 447 * After sending probe requests, wait for probe responses 448 * on the channel. 449 */ 450 *next_delay = IEEE80211_CHANNEL_TIME; 451 local->next_scan_state = SCAN_DECISION; 452} 453 454static int __ieee80211_start_scan(struct ieee80211_sub_if_data *sdata, 455 struct cfg80211_scan_request *req) 456{ 457 struct ieee80211_local *local = sdata->local; 458 int rc; 459 460 lockdep_assert_held(&local->mtx); 461 462 if (local->scan_req) 463 return -EBUSY; 464 465 if (!ieee80211_can_scan(local, sdata)) { 466 /* wait for the work to finish/time out */ 467 local->scan_req = req; 468 rcu_assign_pointer(local->scan_sdata, sdata); 469 return 0; 470 } 471 472 if (local->ops->hw_scan) { 473 u8 *ies; 474 475 local->hw_scan_ies_bufsize = local->scan_ies_len + req->ie_len; 476 local->hw_scan_req = kmalloc( 477 sizeof(*local->hw_scan_req) + 478 req->n_channels * sizeof(req->channels[0]) + 479 local->hw_scan_ies_bufsize, GFP_KERNEL); 480 if (!local->hw_scan_req) 481 return -ENOMEM; 482 483 local->hw_scan_req->ssids = req->ssids; 484 local->hw_scan_req->n_ssids = req->n_ssids; 485 ies = (u8 *)local->hw_scan_req + 486 sizeof(*local->hw_scan_req) + 487 req->n_channels * sizeof(req->channels[0]); 488 local->hw_scan_req->ie = ies; 489 local->hw_scan_req->flags = req->flags; 490 491 local->hw_scan_band = 0; 492 493 /* 494 * After allocating local->hw_scan_req, we must 495 * go through until ieee80211_prep_hw_scan(), so 496 * anything that might be changed here and leave 497 * this function early must not go after this 498 * allocation. 499 */ 500 } 501 502 local->scan_req = req; 503 rcu_assign_pointer(local->scan_sdata, sdata); 504 505 if (local->ops->hw_scan) { 506 __set_bit(SCAN_HW_SCANNING, &local->scanning); 507 } else if ((req->n_channels == 1) && 508 (req->channels[0] == local->_oper_chandef.chan)) { 509 /* 510 * If we are scanning only on the operating channel 511 * then we do not need to stop normal activities 512 */ 513 unsigned long next_delay; 514 515 __set_bit(SCAN_ONCHANNEL_SCANNING, &local->scanning); 516 517 ieee80211_recalc_idle(local); 518 519 /* Notify driver scan is starting, keep order of operations 520 * same as normal software scan, in case that matters. */ 521 drv_sw_scan_start(local); 522 523 ieee80211_configure_filter(local); /* accept probe-responses */ 524 525 /* We need to ensure power level is at max for scanning. */ 526 ieee80211_hw_config(local, 0); 527 528 if ((req->channels[0]->flags & 529 IEEE80211_CHAN_NO_IR) || 530 !local->scan_req->n_ssids) { 531 next_delay = IEEE80211_PASSIVE_CHANNEL_TIME; 532 } else { 533 ieee80211_scan_state_send_probe(local, &next_delay); 534 next_delay = IEEE80211_CHANNEL_TIME; 535 } 536 537 /* Now, just wait a bit and we are all done! */ 538 ieee80211_queue_delayed_work(&local->hw, &local->scan_work, 539 next_delay); 540 return 0; 541 } else { 542 /* Do normal software scan */ 543 __set_bit(SCAN_SW_SCANNING, &local->scanning); 544 } 545 546 ieee80211_recalc_idle(local); 547 548 if (local->ops->hw_scan) { 549 WARN_ON(!ieee80211_prep_hw_scan(local)); 550 rc = drv_hw_scan(local, sdata, local->hw_scan_req); 551 } else 552 rc = ieee80211_start_sw_scan(local); 553 554 if (rc) { 555 kfree(local->hw_scan_req); 556 local->hw_scan_req = NULL; 557 local->scanning = 0; 558 559 ieee80211_recalc_idle(local); 560 561 local->scan_req = NULL; 562 RCU_INIT_POINTER(local->scan_sdata, NULL); 563 } 564 565 return rc; 566} 567 568static unsigned long 569ieee80211_scan_get_channel_time(struct ieee80211_channel *chan) 570{ 571 /* 572 * TODO: channel switching also consumes quite some time, 573 * add that delay as well to get a better estimation 574 */ 575 if (chan->flags & IEEE80211_CHAN_NO_IR) 576 return IEEE80211_PASSIVE_CHANNEL_TIME; 577 return IEEE80211_PROBE_DELAY + IEEE80211_CHANNEL_TIME; 578} 579 580static void ieee80211_scan_state_decision(struct ieee80211_local *local, 581 unsigned long *next_delay) 582{ 583 bool associated = false; 584 bool tx_empty = true; 585 bool bad_latency; 586 struct ieee80211_sub_if_data *sdata; 587 struct ieee80211_channel *next_chan; 588 enum mac80211_scan_state next_scan_state; 589 590 /* 591 * check if at least one STA interface is associated, 592 * check if at least one STA interface has pending tx frames 593 * and grab the lowest used beacon interval 594 */ 595 mutex_lock(&local->iflist_mtx); 596 list_for_each_entry(sdata, &local->interfaces, list) { 597 if (!ieee80211_sdata_running(sdata)) 598 continue; 599 600 if (sdata->vif.type == NL80211_IFTYPE_STATION) { 601 if (sdata->u.mgd.associated) { 602 associated = true; 603 604 if (!qdisc_all_tx_empty(sdata->dev)) { 605 tx_empty = false; 606 break; 607 } 608 } 609 } 610 } 611 mutex_unlock(&local->iflist_mtx); 612 613 next_chan = local->scan_req->channels[local->scan_channel_idx]; 614 615 /* 616 * we're currently scanning a different channel, let's 617 * see if we can scan another channel without interfering 618 * with the current traffic situation. 619 * 620 * Keep good latency, do not stay off-channel more than 125 ms. 621 */ 622 623 bad_latency = time_after(jiffies + 624 ieee80211_scan_get_channel_time(next_chan), 625 local->leave_oper_channel_time + HZ / 8); 626 627 if (associated && !tx_empty) { 628 if (local->scan_req->flags & NL80211_SCAN_FLAG_LOW_PRIORITY) 629 next_scan_state = SCAN_ABORT; 630 else 631 next_scan_state = SCAN_SUSPEND; 632 } else if (associated && bad_latency) { 633 next_scan_state = SCAN_SUSPEND; 634 } else { 635 next_scan_state = SCAN_SET_CHANNEL; 636 } 637 638 local->next_scan_state = next_scan_state; 639 640 *next_delay = 0; 641} 642 643static void ieee80211_scan_state_set_channel(struct ieee80211_local *local, 644 unsigned long *next_delay) 645{ 646 int skip; 647 struct ieee80211_channel *chan; 648 enum nl80211_bss_scan_width oper_scan_width; 649 650 skip = 0; 651 chan = local->scan_req->channels[local->scan_channel_idx]; 652 653 local->scan_chandef.chan = chan; 654 local->scan_chandef.center_freq1 = chan->center_freq; 655 local->scan_chandef.center_freq2 = 0; 656 switch (local->scan_req->scan_width) { 657 case NL80211_BSS_CHAN_WIDTH_5: 658 local->scan_chandef.width = NL80211_CHAN_WIDTH_5; 659 break; 660 case NL80211_BSS_CHAN_WIDTH_10: 661 local->scan_chandef.width = NL80211_CHAN_WIDTH_10; 662 break; 663 case NL80211_BSS_CHAN_WIDTH_20: 664 /* If scanning on oper channel, use whatever channel-type 665 * is currently in use. 666 */ 667 oper_scan_width = cfg80211_chandef_to_scan_width( 668 &local->_oper_chandef); 669 if (chan == local->_oper_chandef.chan && 670 oper_scan_width == local->scan_req->scan_width) 671 local->scan_chandef = local->_oper_chandef; 672 else 673 local->scan_chandef.width = NL80211_CHAN_WIDTH_20_NOHT; 674 break; 675 } 676 677 if (ieee80211_hw_config(local, IEEE80211_CONF_CHANGE_CHANNEL)) 678 skip = 1; 679 680 /* advance state machine to next channel/band */ 681 local->scan_channel_idx++; 682 683 if (skip) { 684 /* if we skip this channel return to the decision state */ 685 local->next_scan_state = SCAN_DECISION; 686 return; 687 } 688 689 /* 690 * Probe delay is used to update the NAV, cf. 11.1.3.2.2 691 * (which unfortunately doesn't say _why_ step a) is done, 692 * but it waits for the probe delay or until a frame is 693 * received - and the received frame would update the NAV). 694 * For now, we do not support waiting until a frame is 695 * received. 696 * 697 * In any case, it is not necessary for a passive scan. 698 */ 699 if (chan->flags & IEEE80211_CHAN_NO_IR || 700 !local->scan_req->n_ssids) { 701 *next_delay = IEEE80211_PASSIVE_CHANNEL_TIME; 702 local->next_scan_state = SCAN_DECISION; 703 return; 704 } 705 706 /* active scan, send probes */ 707 *next_delay = IEEE80211_PROBE_DELAY; 708 local->next_scan_state = SCAN_SEND_PROBE; 709} 710 711static void ieee80211_scan_state_suspend(struct ieee80211_local *local, 712 unsigned long *next_delay) 713{ 714 /* switch back to the operating channel */ 715 local->scan_chandef.chan = NULL; 716 ieee80211_hw_config(local, IEEE80211_CONF_CHANGE_CHANNEL); 717 718 /* disable PS */ 719 ieee80211_offchannel_return(local); 720 721 *next_delay = HZ / 5; 722 /* afterwards, resume scan & go to next channel */ 723 local->next_scan_state = SCAN_RESUME; 724} 725 726static void ieee80211_scan_state_resume(struct ieee80211_local *local, 727 unsigned long *next_delay) 728{ 729 ieee80211_offchannel_stop_vifs(local); 730 731 if (local->ops->flush) { 732 ieee80211_flush_queues(local, NULL); 733 *next_delay = 0; 734 } else 735 *next_delay = HZ / 10; 736 737 /* remember when we left the operating channel */ 738 local->leave_oper_channel_time = jiffies; 739 740 /* advance to the next channel to be scanned */ 741 local->next_scan_state = SCAN_SET_CHANNEL; 742} 743 744void ieee80211_scan_work(struct work_struct *work) 745{ 746 struct ieee80211_local *local = 747 container_of(work, struct ieee80211_local, scan_work.work); 748 struct ieee80211_sub_if_data *sdata; 749 unsigned long next_delay = 0; 750 bool aborted; 751 752 mutex_lock(&local->mtx); 753 754 sdata = rcu_dereference_protected(local->scan_sdata, 755 lockdep_is_held(&local->mtx)); 756 757 /* When scanning on-channel, the first-callback means completed. */ 758 if (test_bit(SCAN_ONCHANNEL_SCANNING, &local->scanning)) { 759 aborted = test_and_clear_bit(SCAN_ABORTED, &local->scanning); 760 goto out_complete; 761 } 762 763 if (test_and_clear_bit(SCAN_COMPLETED, &local->scanning)) { 764 aborted = test_and_clear_bit(SCAN_ABORTED, &local->scanning); 765 goto out_complete; 766 } 767 768 if (!sdata || !local->scan_req) 769 goto out; 770 771 if (local->scan_req && !local->scanning) { 772 struct cfg80211_scan_request *req = local->scan_req; 773 int rc; 774 775 local->scan_req = NULL; 776 RCU_INIT_POINTER(local->scan_sdata, NULL); 777 778 rc = __ieee80211_start_scan(sdata, req); 779 if (rc) { 780 /* need to complete scan in cfg80211 */ 781 local->scan_req = req; 782 aborted = true; 783 goto out_complete; 784 } else 785 goto out; 786 } 787 788 /* 789 * as long as no delay is required advance immediately 790 * without scheduling a new work 791 */ 792 do { 793 if (!ieee80211_sdata_running(sdata)) { 794 aborted = true; 795 goto out_complete; 796 } 797 798 switch (local->next_scan_state) { 799 case SCAN_DECISION: 800 /* if no more bands/channels left, complete scan */ 801 if (local->scan_channel_idx >= local->scan_req->n_channels) { 802 aborted = false; 803 goto out_complete; 804 } 805 ieee80211_scan_state_decision(local, &next_delay); 806 break; 807 case SCAN_SET_CHANNEL: 808 ieee80211_scan_state_set_channel(local, &next_delay); 809 break; 810 case SCAN_SEND_PROBE: 811 ieee80211_scan_state_send_probe(local, &next_delay); 812 break; 813 case SCAN_SUSPEND: 814 ieee80211_scan_state_suspend(local, &next_delay); 815 break; 816 case SCAN_RESUME: 817 ieee80211_scan_state_resume(local, &next_delay); 818 break; 819 case SCAN_ABORT: 820 aborted = true; 821 goto out_complete; 822 } 823 } while (next_delay == 0); 824 825 ieee80211_queue_delayed_work(&local->hw, &local->scan_work, next_delay); 826 goto out; 827 828out_complete: 829 __ieee80211_scan_completed(&local->hw, aborted); 830out: 831 mutex_unlock(&local->mtx); 832} 833 834int ieee80211_request_scan(struct ieee80211_sub_if_data *sdata, 835 struct cfg80211_scan_request *req) 836{ 837 int res; 838 839 mutex_lock(&sdata->local->mtx); 840 res = __ieee80211_start_scan(sdata, req); 841 mutex_unlock(&sdata->local->mtx); 842 843 return res; 844} 845 846int ieee80211_request_ibss_scan(struct ieee80211_sub_if_data *sdata, 847 const u8 *ssid, u8 ssid_len, 848 struct ieee80211_channel *chan, 849 enum nl80211_bss_scan_width scan_width) 850{ 851 struct ieee80211_local *local = sdata->local; 852 int ret = -EBUSY; 853 enum ieee80211_band band; 854 855 mutex_lock(&local->mtx); 856 857 /* busy scanning */ 858 if (local->scan_req) 859 goto unlock; 860 861 /* fill internal scan request */ 862 if (!chan) { 863 int i, max_n; 864 int n_ch = 0; 865 866 for (band = 0; band < IEEE80211_NUM_BANDS; band++) { 867 if (!local->hw.wiphy->bands[band]) 868 continue; 869 870 max_n = local->hw.wiphy->bands[band]->n_channels; 871 for (i = 0; i < max_n; i++) { 872 struct ieee80211_channel *tmp_ch = 873 &local->hw.wiphy->bands[band]->channels[i]; 874 875 if (tmp_ch->flags & (IEEE80211_CHAN_NO_IR | 876 IEEE80211_CHAN_DISABLED)) 877 continue; 878 879 local->int_scan_req->channels[n_ch] = tmp_ch; 880 n_ch++; 881 } 882 } 883 884 if (WARN_ON_ONCE(n_ch == 0)) 885 goto unlock; 886 887 local->int_scan_req->n_channels = n_ch; 888 } else { 889 if (WARN_ON_ONCE(chan->flags & (IEEE80211_CHAN_NO_IR | 890 IEEE80211_CHAN_DISABLED))) 891 goto unlock; 892 893 local->int_scan_req->channels[0] = chan; 894 local->int_scan_req->n_channels = 1; 895 } 896 897 local->int_scan_req->ssids = &local->scan_ssid; 898 local->int_scan_req->n_ssids = 1; 899 local->int_scan_req->scan_width = scan_width; 900 memcpy(local->int_scan_req->ssids[0].ssid, ssid, IEEE80211_MAX_SSID_LEN); 901 local->int_scan_req->ssids[0].ssid_len = ssid_len; 902 903 ret = __ieee80211_start_scan(sdata, sdata->local->int_scan_req); 904 unlock: 905 mutex_unlock(&local->mtx); 906 return ret; 907} 908 909/* 910 * Only call this function when a scan can't be queued -- under RTNL. 911 */ 912void ieee80211_scan_cancel(struct ieee80211_local *local) 913{ 914 /* 915 * We are canceling software scan, or deferred scan that was not 916 * yet really started (see __ieee80211_start_scan ). 917 * 918 * Regarding hardware scan: 919 * - we can not call __ieee80211_scan_completed() as when 920 * SCAN_HW_SCANNING bit is set this function change 921 * local->hw_scan_req to operate on 5G band, what race with 922 * driver which can use local->hw_scan_req 923 * 924 * - we can not cancel scan_work since driver can schedule it 925 * by ieee80211_scan_completed(..., true) to finish scan 926 * 927 * Hence we only call the cancel_hw_scan() callback, but the low-level 928 * driver is still responsible for calling ieee80211_scan_completed() 929 * after the scan was completed/aborted. 930 */ 931 932 mutex_lock(&local->mtx); 933 if (!local->scan_req) 934 goto out; 935 936 /* 937 * We have a scan running and the driver already reported completion, 938 * but the worker hasn't run yet or is stuck on the mutex - mark it as 939 * cancelled. 940 */ 941 if (test_bit(SCAN_HW_SCANNING, &local->scanning) && 942 test_bit(SCAN_COMPLETED, &local->scanning)) { 943 set_bit(SCAN_HW_CANCELLED, &local->scanning); 944 goto out; 945 } 946 947 if (test_bit(SCAN_HW_SCANNING, &local->scanning)) { 948 /* 949 * Make sure that __ieee80211_scan_completed doesn't trigger a 950 * scan on another band. 951 */ 952 set_bit(SCAN_HW_CANCELLED, &local->scanning); 953 if (local->ops->cancel_hw_scan) 954 drv_cancel_hw_scan(local, 955 rcu_dereference_protected(local->scan_sdata, 956 lockdep_is_held(&local->mtx))); 957 goto out; 958 } 959 960 /* 961 * If the work is currently running, it must be blocked on 962 * the mutex, but we'll set scan_sdata = NULL and it'll 963 * simply exit once it acquires the mutex. 964 */ 965 cancel_delayed_work(&local->scan_work); 966 /* and clean up */ 967 __ieee80211_scan_completed(&local->hw, true); 968out: 969 mutex_unlock(&local->mtx); 970} 971 972int __ieee80211_request_sched_scan_start(struct ieee80211_sub_if_data *sdata, 973 struct cfg80211_sched_scan_request *req) 974{ 975 struct ieee80211_local *local = sdata->local; 976 struct ieee80211_sched_scan_ies sched_scan_ies = {}; 977 struct cfg80211_chan_def chandef; 978 int ret, i, iebufsz; 979 980 iebufsz = local->scan_ies_len + req->ie_len; 981 982 lockdep_assert_held(&local->mtx); 983 984 if (!local->ops->sched_scan_start) 985 return -ENOTSUPP; 986 987 for (i = 0; i < IEEE80211_NUM_BANDS; i++) { 988 if (!local->hw.wiphy->bands[i]) 989 continue; 990 991 sched_scan_ies.ie[i] = kzalloc(iebufsz, GFP_KERNEL); 992 if (!sched_scan_ies.ie[i]) { 993 ret = -ENOMEM; 994 goto out_free; 995 } 996 997 ieee80211_prepare_scan_chandef(&chandef, req->scan_width); 998 999 sched_scan_ies.len[i] = 1000 ieee80211_build_preq_ies(local, sched_scan_ies.ie[i], 1001 iebufsz, req->ie, req->ie_len, 1002 i, (u32) -1, &chandef); 1003 } 1004 1005 ret = drv_sched_scan_start(local, sdata, req, &sched_scan_ies); 1006 if (ret == 0) { 1007 rcu_assign_pointer(local->sched_scan_sdata, sdata); 1008 local->sched_scan_req = req; 1009 } 1010 1011out_free: 1012 while (i > 0) 1013 kfree(sched_scan_ies.ie[--i]); 1014 1015 if (ret) { 1016 /* Clean in case of failure after HW restart or upon resume. */ 1017 RCU_INIT_POINTER(local->sched_scan_sdata, NULL); 1018 local->sched_scan_req = NULL; 1019 } 1020 1021 return ret; 1022} 1023 1024int ieee80211_request_sched_scan_start(struct ieee80211_sub_if_data *sdata, 1025 struct cfg80211_sched_scan_request *req) 1026{ 1027 struct ieee80211_local *local = sdata->local; 1028 int ret; 1029 1030 mutex_lock(&local->mtx); 1031 1032 if (rcu_access_pointer(local->sched_scan_sdata)) { 1033 mutex_unlock(&local->mtx); 1034 return -EBUSY; 1035 } 1036 1037 ret = __ieee80211_request_sched_scan_start(sdata, req); 1038 1039 mutex_unlock(&local->mtx); 1040 return ret; 1041} 1042 1043int ieee80211_request_sched_scan_stop(struct ieee80211_sub_if_data *sdata) 1044{ 1045 struct ieee80211_local *local = sdata->local; 1046 int ret = 0; 1047 1048 mutex_lock(&local->mtx); 1049 1050 if (!local->ops->sched_scan_stop) { 1051 ret = -ENOTSUPP; 1052 goto out; 1053 } 1054 1055 /* We don't want to restart sched scan anymore. */ 1056 local->sched_scan_req = NULL; 1057 1058 if (rcu_access_pointer(local->sched_scan_sdata)) { 1059 ret = drv_sched_scan_stop(local, sdata); 1060 if (!ret) 1061 rcu_assign_pointer(local->sched_scan_sdata, NULL); 1062 } 1063out: 1064 mutex_unlock(&local->mtx); 1065 1066 return ret; 1067} 1068 1069void ieee80211_sched_scan_results(struct ieee80211_hw *hw) 1070{ 1071 struct ieee80211_local *local = hw_to_local(hw); 1072 1073 trace_api_sched_scan_results(local); 1074 1075 cfg80211_sched_scan_results(hw->wiphy); 1076} 1077EXPORT_SYMBOL(ieee80211_sched_scan_results); 1078 1079void ieee80211_sched_scan_stopped_work(struct work_struct *work) 1080{ 1081 struct ieee80211_local *local = 1082 container_of(work, struct ieee80211_local, 1083 sched_scan_stopped_work); 1084 1085 mutex_lock(&local->mtx); 1086 1087 if (!rcu_access_pointer(local->sched_scan_sdata)) { 1088 mutex_unlock(&local->mtx); 1089 return; 1090 } 1091 1092 RCU_INIT_POINTER(local->sched_scan_sdata, NULL); 1093 1094 /* If sched scan was aborted by the driver. */ 1095 local->sched_scan_req = NULL; 1096 1097 mutex_unlock(&local->mtx); 1098 1099 cfg80211_sched_scan_stopped(local->hw.wiphy); 1100} 1101 1102void ieee80211_sched_scan_stopped(struct ieee80211_hw *hw) 1103{ 1104 struct ieee80211_local *local = hw_to_local(hw); 1105 1106 trace_api_sched_scan_stopped(local); 1107 1108 schedule_work(&local->sched_scan_stopped_work); 1109} 1110EXPORT_SYMBOL(ieee80211_sched_scan_stopped); 1111