net/mac80211/scan.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  * Scanning implementation
   4  *
   5  * Copyright 2003, Jouni Malinen <jkmaline@cc.hut.fi>
   6  * Copyright 2004, Instant802 Networks, Inc.
   7  * Copyright 2005, Devicescape Software, Inc.
   8  * Copyright 2006-2007  Jiri Benc <jbenc@suse.cz>
   9  * Copyright 2007, Michael Wu <flamingice@sourmilk.net>
  10  * Copyright 2013-2015  Intel Mobile Communications GmbH
  11  * Copyright 2016-2017  Intel Deutschland GmbH
  12  * Copyright (C) 2018-2019 Intel Corporation
  13  */
  14
  15 #include <linux/if_arp.h>
  16 #include <linux/etherdevice.h>
  17 #include <linux/rtnetlink.h>
  18 #include <net/sch_generic.h>
  19 #include <linux/slab.h>
  20 #include <linux/export.h>
  21 #include <linux/random.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
  32 void 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
  41 static 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
  58 static void
  59 ieee80211_update_bss_from_elems(struct ieee80211_local *local,
  60                                 struct ieee80211_bss *bss,
  61                                 struct ieee802_11_elems *elems,
  62                                 struct ieee80211_rx_status *rx_status,
  63                                 bool beacon)
  64 {
  65         int clen, srlen;
  66
  67         if (beacon)
  68                 bss->device_ts_beacon = rx_status->device_timestamp;
  69         else
  70                 bss->device_ts_presp = rx_status->device_timestamp;
  71
  72         if (elems->parse_error) {
  73                 if (beacon)
  74                         bss->corrupt_data |= IEEE80211_BSS_CORRUPT_BEACON;
  75                 else
  76                         bss->corrupt_data |= IEEE80211_BSS_CORRUPT_PROBE_RESP;
  77         } else {
  78                 if (beacon)
  79                         bss->corrupt_data &= ~IEEE80211_BSS_CORRUPT_BEACON;
  80                 else
  81                         bss->corrupt_data &= ~IEEE80211_BSS_CORRUPT_PROBE_RESP;
  82         }
  83
  84         /* save the ERP value so that it is available at association time */
  85         if (elems->erp_info && (!elems->parse_error ||
  86                                 !(bss->valid_data & IEEE80211_BSS_VALID_ERP))) {
  87                 bss->erp_value = elems->erp_info[0];
  88                 bss->has_erp_value = true;
  89                 if (!elems->parse_error)
  90                         bss->valid_data |= IEEE80211_BSS_VALID_ERP;
  91         }
  92
  93         /* replace old supported rates if we get new values */
  94         if (!elems->parse_error ||
  95             !(bss->valid_data & IEEE80211_BSS_VALID_RATES)) {
  96                 srlen = 0;
  97                 if (elems->supp_rates) {
  98                         clen = IEEE80211_MAX_SUPP_RATES;
  99                         if (clen > elems->supp_rates_len)
 100                                 clen = elems->supp_rates_len;
 101                         memcpy(bss->supp_rates, elems->supp_rates, clen);
 102                         srlen += clen;
 103                 }
 104                 if (elems->ext_supp_rates) {
 105                         clen = IEEE80211_MAX_SUPP_RATES - srlen;
 106                         if (clen > elems->ext_supp_rates_len)
 107                                 clen = elems->ext_supp_rates_len;
 108                         memcpy(bss->supp_rates + srlen, elems->ext_supp_rates,
 109                                clen);
 110                         srlen += clen;
 111                 }
 112                 if (srlen) {
 113                         bss->supp_rates_len = srlen;
 114                         if (!elems->parse_error)
 115                                 bss->valid_data |= IEEE80211_BSS_VALID_RATES;
 116                 }
 117         }
 118
 119         if (!elems->parse_error ||
 120             !(bss->valid_data & IEEE80211_BSS_VALID_WMM)) {
 121                 bss->wmm_used = elems->wmm_param || elems->wmm_info;
 122                 bss->uapsd_supported = is_uapsd_supported(elems);
 123                 if (!elems->parse_error)
 124                         bss->valid_data |= IEEE80211_BSS_VALID_WMM;
 125         }
 126
 127         if (beacon) {
 128                 struct ieee80211_supported_band *sband =
 129                         local->hw.wiphy->bands[rx_status->band];
 130                 if (!(rx_status->encoding == RX_ENC_HT) &&
 131                     !(rx_status->encoding == RX_ENC_VHT))
 132                         bss->beacon_rate =
 133                                 &sband->bitrates[rx_status->rate_idx];
 134         }
 135
 136         if (elems->vht_cap_elem)
 137                 bss->vht_cap_info =
 138                         le32_to_cpu(elems->vht_cap_elem->vht_cap_info);
 139         else
 140                 bss->vht_cap_info = 0;
 141 }
 142
 143 struct ieee80211_bss *
 144 ieee80211_bss_info_update(struct ieee80211_local *local,
 145                           struct ieee80211_rx_status *rx_status,
 146                           struct ieee80211_mgmt *mgmt, size_t len,
 147                           struct ieee80211_channel *channel)
 148 {
 149         bool beacon = ieee80211_is_beacon(mgmt->frame_control);
 150         struct cfg80211_bss *cbss, *non_tx_cbss;
 151         struct ieee80211_bss *bss, *non_tx_bss;
 152         struct cfg80211_inform_bss bss_meta = {
 153                 .boottime_ns = rx_status->boottime_ns,
 154         };
 155         bool signal_valid;
 156         struct ieee80211_sub_if_data *scan_sdata;
 157         struct ieee802_11_elems elems;
 158         size_t baselen;
 159         u8 *elements;
 160
 161         if (rx_status->flag & RX_FLAG_NO_SIGNAL_VAL)
 162                 bss_meta.signal = 0; /* invalid signal indication */
 163         else if (ieee80211_hw_check(&local->hw, SIGNAL_DBM))
 164                 bss_meta.signal = rx_status->signal * 100;
 165         else if (ieee80211_hw_check(&local->hw, SIGNAL_UNSPEC))
 166                 bss_meta.signal = (rx_status->signal * 100) / local->hw.max_signal;
 167
 168         bss_meta.scan_width = NL80211_BSS_CHAN_WIDTH_20;
 169         if (rx_status->bw == RATE_INFO_BW_5)
 170                 bss_meta.scan_width = NL80211_BSS_CHAN_WIDTH_5;
 171         else if (rx_status->bw == RATE_INFO_BW_10)
 172                 bss_meta.scan_width = NL80211_BSS_CHAN_WIDTH_10;
 173
 174         bss_meta.chan = channel;
 175
 176         rcu_read_lock();
 177         scan_sdata = rcu_dereference(local->scan_sdata);
 178         if (scan_sdata && scan_sdata->vif.type == NL80211_IFTYPE_STATION &&
 179             scan_sdata->vif.bss_conf.assoc &&
 180             ieee80211_have_rx_timestamp(rx_status)) {
 181                 bss_meta.parent_tsf =
 182                         ieee80211_calculate_rx_timestamp(local, rx_status,
 183                                                          len + FCS_LEN, 24);
 184                 ether_addr_copy(bss_meta.parent_bssid,
 185                                 scan_sdata->vif.bss_conf.bssid);
 186         }
 187         rcu_read_unlock();
 188
 189         cbss = cfg80211_inform_bss_frame_data(local->hw.wiphy, &bss_meta,
 190                                               mgmt, len, GFP_ATOMIC);
 191         if (!cbss)
 192                 return NULL;
 193
 194         if (ieee80211_is_probe_resp(mgmt->frame_control)) {
 195                 elements = mgmt->u.probe_resp.variable;
 196                 baselen = offsetof(struct ieee80211_mgmt,
 197                                    u.probe_resp.variable);
 198         } else {
 199                 baselen = offsetof(struct ieee80211_mgmt, u.beacon.variable);
 200                 elements = mgmt->u.beacon.variable;
 201         }
 202
 203         if (baselen > len)
 204                 return NULL;
 205
 206         ieee802_11_parse_elems(elements, len - baselen, false, &elems,
 207                                mgmt->bssid, cbss->bssid);
 208
 209         /* In case the signal is invalid update the status */
 210         signal_valid = channel == cbss->channel;
 211         if (!signal_valid)
 212                 rx_status->flag |= RX_FLAG_NO_SIGNAL_VAL;
 213
 214         bss = (void *)cbss->priv;
 215         ieee80211_update_bss_from_elems(local, bss, &elems, rx_status, beacon);
 216
 217         list_for_each_entry(non_tx_cbss, &cbss->nontrans_list, nontrans_list) {
 218                 non_tx_bss = (void *)non_tx_cbss->priv;
 219
 220                 ieee80211_update_bss_from_elems(local, non_tx_bss, &elems,
 221                                                 rx_status, beacon);
 222         }
 223
 224         return bss;
 225 }
 226
 227 static bool ieee80211_scan_accept_presp(struct ieee80211_sub_if_data *sdata,
 228                                         u32 scan_flags, const u8 *da)
 229 {
 230         if (!sdata)
 231                 return false;
 232         /* accept broadcast for OCE */
 233         if (scan_flags & NL80211_SCAN_FLAG_ACCEPT_BCAST_PROBE_RESP &&
 234             is_broadcast_ether_addr(da))
 235                 return true;
 236         if (scan_flags & NL80211_SCAN_FLAG_RANDOM_ADDR)
 237                 return true;
 238         return ether_addr_equal(da, sdata->vif.addr);
 239 }
 240
 241 void ieee80211_scan_rx(struct ieee80211_local *local, struct sk_buff *skb)
 242 {
 243         struct ieee80211_rx_status *rx_status = IEEE80211_SKB_RXCB(skb);
 244         struct ieee80211_sub_if_data *sdata1, *sdata2;
 245         struct ieee80211_mgmt *mgmt = (void *)skb->data;
 246         struct ieee80211_bss *bss;
 247         struct ieee80211_channel *channel;
 248
 249         if (skb->len < 24 ||
 250             (!ieee80211_is_probe_resp(mgmt->frame_control) &&
 251              !ieee80211_is_beacon(mgmt->frame_control)))
 252                 return;
 253
 254         sdata1 = rcu_dereference(local->scan_sdata);
 255         sdata2 = rcu_dereference(local->sched_scan_sdata);
 256
 257         if (likely(!sdata1 && !sdata2))
 258                 return;
 259
 260         if (ieee80211_is_probe_resp(mgmt->frame_control)) {
 261                 struct cfg80211_scan_request *scan_req;
 262                 struct cfg80211_sched_scan_request *sched_scan_req;
 263                 u32 scan_req_flags = 0, sched_scan_req_flags = 0;
 264
 265                 scan_req = rcu_dereference(local->scan_req);
 266                 sched_scan_req = rcu_dereference(local->sched_scan_req);
 267
 268                 if (scan_req)
 269                         scan_req_flags = scan_req->flags;
 270
 271                 if (sched_scan_req)
 272                         sched_scan_req_flags = sched_scan_req->flags;
 273
 274                 /* ignore ProbeResp to foreign address or non-bcast (OCE)
 275                  * unless scanning with randomised address
 276                  */
 277                 if (!ieee80211_scan_accept_presp(sdata1, scan_req_flags,
 278                                                  mgmt->da) &&
 279                     !ieee80211_scan_accept_presp(sdata2, sched_scan_req_flags,
 280                                                  mgmt->da))
 281                         return;
 282         }
 283
 284         channel = ieee80211_get_channel_khz(local->hw.wiphy,
 285                                         ieee80211_rx_status_to_khz(rx_status));
 286
 287         if (!channel || channel->flags & IEEE80211_CHAN_DISABLED)
 288                 return;
 289
 290         bss = ieee80211_bss_info_update(local, rx_status,
 291                                         mgmt, skb->len,
 292                                         channel);
 293         if (bss)
 294                 ieee80211_rx_bss_put(local, bss);
 295 }
 296
 297 static void
 298 ieee80211_prepare_scan_chandef(struct cfg80211_chan_def *chandef,
 299                                enum nl80211_bss_scan_width scan_width)
 300 {
 301         memset(chandef, 0, sizeof(*chandef));
 302         switch (scan_width) {
 303         case NL80211_BSS_CHAN_WIDTH_5:
 304                 chandef->width = NL80211_CHAN_WIDTH_5;
 305                 break;
 306         case NL80211_BSS_CHAN_WIDTH_10:
 307                 chandef->width = NL80211_CHAN_WIDTH_10;
 308                 break;
 309         default:
 310                 chandef->width = NL80211_CHAN_WIDTH_20_NOHT;
 311                 break;
 312         }
 313 }
 314
 315 /* return false if no more work */
 316 static bool ieee80211_prep_hw_scan(struct ieee80211_sub_if_data *sdata)
 317 {
 318         struct ieee80211_local *local = sdata->local;
 319         struct cfg80211_scan_request *req;
 320         struct cfg80211_chan_def chandef;
 321         u8 bands_used = 0;
 322         int i, ielen, n_chans;
 323         u32 flags = 0;
 324
 325         req = rcu_dereference_protected(local->scan_req,
 326                                         lockdep_is_held(&local->mtx));
 327
 328         if (test_bit(SCAN_HW_CANCELLED, &local->scanning))
 329                 return false;
 330
 331         if (ieee80211_hw_check(&local->hw, SINGLE_SCAN_ON_ALL_BANDS)) {
 332                 for (i = 0; i < req->n_channels; i++) {
 333                         local->hw_scan_req->req.channels[i] = req->channels[i];
 334                         bands_used |= BIT(req->channels[i]->band);
 335                 }
 336
 337                 n_chans = req->n_channels;
 338         } else {
 339                 do {
 340                         if (local->hw_scan_band == NUM_NL80211_BANDS)
 341                                 return false;
 342
 343                         n_chans = 0;
 344
 345                         for (i = 0; i < req->n_channels; i++) {
 346                                 if (req->channels[i]->band !=
 347                                     local->hw_scan_band)
 348                                         continue;
 349                                 local->hw_scan_req->req.channels[n_chans] =
 350                                                         req->channels[i];
 351                                 n_chans++;
 352                                 bands_used |= BIT(req->channels[i]->band);
 353                         }
 354
 355                         local->hw_scan_band++;
 356                 } while (!n_chans);
 357         }
 358
 359         local->hw_scan_req->req.n_channels = n_chans;
 360         ieee80211_prepare_scan_chandef(&chandef, req->scan_width);
 361
 362         if (req->flags & NL80211_SCAN_FLAG_MIN_PREQ_CONTENT)
 363                 flags |= IEEE80211_PROBE_FLAG_MIN_CONTENT;
 364
 365         ielen = ieee80211_build_preq_ies(sdata,
 366                                          (u8 *)local->hw_scan_req->req.ie,
 367                                          local->hw_scan_ies_bufsize,
 368                                          &local->hw_scan_req->ies,
 369                                          req->ie, req->ie_len,
 370                                          bands_used, req->rates, &chandef,
 371                                          flags);
 372         local->hw_scan_req->req.ie_len = ielen;
 373         local->hw_scan_req->req.no_cck = req->no_cck;
 374         ether_addr_copy(local->hw_scan_req->req.mac_addr, req->mac_addr);
 375         ether_addr_copy(local->hw_scan_req->req.mac_addr_mask,
 376                         req->mac_addr_mask);
 377         ether_addr_copy(local->hw_scan_req->req.bssid, req->bssid);
 378
 379         return true;
 380 }
 381
 382 static void __ieee80211_scan_completed(struct ieee80211_hw *hw, bool aborted)
 383 {
 384         struct ieee80211_local *local = hw_to_local(hw);
 385         bool hw_scan = test_bit(SCAN_HW_SCANNING, &local->scanning);
 386         bool was_scanning = local->scanning;
 387         struct cfg80211_scan_request *scan_req;
 388         struct ieee80211_sub_if_data *scan_sdata;
 389         struct ieee80211_sub_if_data *sdata;
 390
 391         lockdep_assert_held(&local->mtx);
 392
 393         /*
 394          * It's ok to abort a not-yet-running scan (that
 395          * we have one at all will be verified by checking
 396          * local->scan_req next), but not to complete it
 397          * successfully.
 398          */
 399         if (WARN_ON(!local->scanning && !aborted))
 400                 aborted = true;
 401
 402         if (WARN_ON(!local->scan_req))
 403                 return;
 404
 405         scan_sdata = rcu_dereference_protected(local->scan_sdata,
 406                                                lockdep_is_held(&local->mtx));
 407
 408         if (hw_scan && !aborted &&
 409             !ieee80211_hw_check(&local->hw, SINGLE_SCAN_ON_ALL_BANDS) &&
 410             ieee80211_prep_hw_scan(scan_sdata)) {
 411                 int rc;
 412
 413                 rc = drv_hw_scan(local,
 414                         rcu_dereference_protected(local->scan_sdata,
 415                                                   lockdep_is_held(&local->mtx)),
 416                         local->hw_scan_req);
 417
 418                 if (rc == 0)
 419                         return;
 420
 421                 /* HW scan failed and is going to be reported as aborted,
 422                  * so clear old scan info.
 423                  */
 424                 memset(&local->scan_info, 0, sizeof(local->scan_info));
 425                 aborted = true;
 426         }
 427
 428         kfree(local->hw_scan_req);
 429         local->hw_scan_req = NULL;
 430
 431         scan_req = rcu_dereference_protected(local->scan_req,
 432                                              lockdep_is_held(&local->mtx));
 433
 434         if (scan_req != local->int_scan_req) {
 435                 local->scan_info.aborted = aborted;
 436                 cfg80211_scan_done(scan_req, &local->scan_info);
 437         }
 438         RCU_INIT_POINTER(local->scan_req, NULL);
 439         RCU_INIT_POINTER(local->scan_sdata, NULL);
 440
 441         local->scanning = 0;
 442         local->scan_chandef.chan = NULL;
 443
 444         /* Set power back to normal operating levels. */
 445         ieee80211_hw_config(local, 0);
 446
 447         if (!hw_scan) {
 448                 ieee80211_configure_filter(local);
 449                 drv_sw_scan_complete(local, scan_sdata);
 450                 ieee80211_offchannel_return(local);
 451         }
 452
 453         ieee80211_recalc_idle(local);
 454
 455         ieee80211_mlme_notify_scan_completed(local);
 456         ieee80211_ibss_notify_scan_completed(local);
 457
 458         /* Requeue all the work that might have been ignored while
 459          * the scan was in progress; if there was none this will
 460          * just be a no-op for the particular interface.
 461          */
 462         list_for_each_entry_rcu(sdata, &local->interfaces, list) {
 463                 if (ieee80211_sdata_running(sdata))
 464                         ieee80211_queue_work(&sdata->local->hw, &sdata->work);
 465         }
 466
 467         if (was_scanning)
 468                 ieee80211_start_next_roc(local);
 469 }
 470
 471 void ieee80211_scan_completed(struct ieee80211_hw *hw,
 472                               struct cfg80211_scan_info *info)
 473 {
 474         struct ieee80211_local *local = hw_to_local(hw);
 475
 476         trace_api_scan_completed(local, info->aborted);
 477
 478         set_bit(SCAN_COMPLETED, &local->scanning);
 479         if (info->aborted)
 480                 set_bit(SCAN_ABORTED, &local->scanning);
 481
 482         memcpy(&local->scan_info, info, sizeof(*info));
 483
 484         ieee80211_queue_delayed_work(&local->hw, &local->scan_work, 0);
 485 }
 486 EXPORT_SYMBOL(ieee80211_scan_completed);
 487
 488 static int ieee80211_start_sw_scan(struct ieee80211_local *local,
 489                                    struct ieee80211_sub_if_data *sdata)
 490 {
 491         /* Software scan is not supported in multi-channel cases */
 492         if (local->use_chanctx)
 493                 return -EOPNOTSUPP;
 494
 495         /*
 496          * Hardware/driver doesn't support hw_scan, so use software
 497          * scanning instead. First send a nullfunc frame with power save
 498          * bit on so that AP will buffer the frames for us while we are not
 499          * listening, then send probe requests to each channel and wait for
 500          * the responses. After all channels are scanned, tune back to the
 501          * original channel and send a nullfunc frame with power save bit
 502          * off to trigger the AP to send us all the buffered frames.
 503          *
 504          * Note that while local->sw_scanning is true everything else but
 505          * nullfunc frames and probe requests will be dropped in
 506          * ieee80211_tx_h_check_assoc().
 507          */
 508         drv_sw_scan_start(local, sdata, local->scan_addr);
 509
 510         local->leave_oper_channel_time = jiffies;
 511         local->next_scan_state = SCAN_DECISION;
 512         local->scan_channel_idx = 0;
 513
 514         ieee80211_offchannel_stop_vifs(local);
 515
 516         /* ensure nullfunc is transmitted before leaving operating channel */
 517         ieee80211_flush_queues(local, NULL, false);
 518
 519         ieee80211_configure_filter(local);
 520
 521         /* We need to set power level at maximum rate for scanning. */
 522         ieee80211_hw_config(local, 0);
 523
 524         ieee80211_queue_delayed_work(&local->hw,
 525                                      &local->scan_work, 0);
 526
 527         return 0;
 528 }
 529
 530 static bool __ieee80211_can_leave_ch(struct ieee80211_sub_if_data *sdata)
 531 {
 532         struct ieee80211_local *local = sdata->local;
 533         struct ieee80211_sub_if_data *sdata_iter;
 534
 535         if (!ieee80211_is_radar_required(local))
 536                 return true;
 537
 538         if (!regulatory_pre_cac_allowed(local->hw.wiphy))
 539                 return false;
 540
 541         mutex_lock(&local->iflist_mtx);
 542         list_for_each_entry(sdata_iter, &local->interfaces, list) {
 543                 if (sdata_iter->wdev.cac_started) {
 544                         mutex_unlock(&local->iflist_mtx);
 545                         return false;
 546                 }
 547         }
 548         mutex_unlock(&local->iflist_mtx);
 549
 550         return true;
 551 }
 552
 553 static bool ieee80211_can_scan(struct ieee80211_local *local,
 554                                struct ieee80211_sub_if_data *sdata)
 555 {
 556         if (!__ieee80211_can_leave_ch(sdata))
 557                 return false;
 558
 559         if (!list_empty(&local->roc_list))
 560                 return false;
 561
 562         if (sdata->vif.type == NL80211_IFTYPE_STATION &&
 563             sdata->u.mgd.flags & IEEE80211_STA_CONNECTION_POLL)
 564                 return false;
 565
 566         return true;
 567 }
 568
 569 void ieee80211_run_deferred_scan(struct ieee80211_local *local)
 570 {
 571         lockdep_assert_held(&local->mtx);
 572
 573         if (!local->scan_req || local->scanning)
 574                 return;
 575
 576         if (!ieee80211_can_scan(local,
 577                                 rcu_dereference_protected(
 578                                         local->scan_sdata,
 579                                         lockdep_is_held(&local->mtx))))
 580                 return;
 581
 582         ieee80211_queue_delayed_work(&local->hw, &local->scan_work,
 583                                      round_jiffies_relative(0));
 584 }
 585
 586 static void ieee80211_send_scan_probe_req(struct ieee80211_sub_if_data *sdata,
 587                                           const u8 *src, const u8 *dst,
 588                                           const u8 *ssid, size_t ssid_len,
 589                                           const u8 *ie, size_t ie_len,
 590                                           u32 ratemask, u32 flags, u32 tx_flags,
 591                                           struct ieee80211_channel *channel)
 592 {
 593         struct sk_buff *skb;
 594
 595         skb = ieee80211_build_probe_req(sdata, src, dst, ratemask, channel,
 596                                         ssid, ssid_len,
 597                                         ie, ie_len, flags);
 598
 599         if (skb) {
 600                 if (flags & IEEE80211_PROBE_FLAG_RANDOM_SN) {
 601                         struct ieee80211_hdr *hdr = (void *)skb->data;
 602                         struct ieee80211_tx_info *info = IEEE80211_SKB_CB(skb);
 603                         u16 sn = get_random_u32();
 604
 605                         info->control.flags |= IEEE80211_TX_CTRL_NO_SEQNO;
 606                         hdr->seq_ctrl =
 607                                 cpu_to_le16(IEEE80211_SN_TO_SEQ(sn));
 608                 }
 609                 IEEE80211_SKB_CB(skb)->flags |= tx_flags;
 610                 ieee80211_tx_skb_tid_band(sdata, skb, 7, channel->band);
 611         }
 612 }
 613
 614 static void ieee80211_scan_state_send_probe(struct ieee80211_local *local,
 615                                             unsigned long *next_delay)
 616 {
 617         int i;
 618         struct ieee80211_sub_if_data *sdata;
 619         struct cfg80211_scan_request *scan_req;
 620         enum nl80211_band band = local->hw.conf.chandef.chan->band;
 621         u32 flags = 0, tx_flags;
 622
 623         scan_req = rcu_dereference_protected(local->scan_req,
 624                                              lockdep_is_held(&local->mtx));
 625
 626         tx_flags = IEEE80211_TX_INTFL_OFFCHAN_TX_OK;
 627         if (scan_req->no_cck)
 628                 tx_flags |= IEEE80211_TX_CTL_NO_CCK_RATE;
 629         if (scan_req->flags & NL80211_SCAN_FLAG_MIN_PREQ_CONTENT)
 630                 flags |= IEEE80211_PROBE_FLAG_MIN_CONTENT;
 631         if (scan_req->flags & NL80211_SCAN_FLAG_RANDOM_SN)
 632                 flags |= IEEE80211_PROBE_FLAG_RANDOM_SN;
 633
 634         sdata = rcu_dereference_protected(local->scan_sdata,
 635                                           lockdep_is_held(&local->mtx));
 636
 637         for (i = 0; i < scan_req->n_ssids; i++)
 638                 ieee80211_send_scan_probe_req(
 639                         sdata, local->scan_addr, scan_req->bssid,
 640                         scan_req->ssids[i].ssid, scan_req->ssids[i].ssid_len,
 641                         scan_req->ie, scan_req->ie_len,
 642                         scan_req->rates[band], flags,
 643                         tx_flags, local->hw.conf.chandef.chan);
 644
 645         /*
 646          * After sending probe requests, wait for probe responses
 647          * on the channel.
 648          */
 649         *next_delay = IEEE80211_CHANNEL_TIME;
 650         local->next_scan_state = SCAN_DECISION;
 651 }
 652
 653 static int __ieee80211_start_scan(struct ieee80211_sub_if_data *sdata,
 654                                   struct cfg80211_scan_request *req)
 655 {
 656         struct ieee80211_local *local = sdata->local;
 657         bool hw_scan = local->ops->hw_scan;
 658         int rc;
 659
 660         lockdep_assert_held(&local->mtx);
 661
 662         if (local->scan_req)
 663                 return -EBUSY;
 664
 665         if (!__ieee80211_can_leave_ch(sdata))
 666                 return -EBUSY;
 667
 668         if (!ieee80211_can_scan(local, sdata)) {
 669                 /* wait for the work to finish/time out */
 670                 rcu_assign_pointer(local->scan_req, req);
 671                 rcu_assign_pointer(local->scan_sdata, sdata);
 672                 return 0;
 673         }
 674
 675  again:
 676         if (hw_scan) {
 677                 u8 *ies;
 678
 679                 local->hw_scan_ies_bufsize = local->scan_ies_len + req->ie_len;
 680
 681                 if (ieee80211_hw_check(&local->hw, SINGLE_SCAN_ON_ALL_BANDS)) {
 682                         int i, n_bands = 0;
 683                         u8 bands_counted = 0;
 684
 685                         for (i = 0; i < req->n_channels; i++) {
 686                                 if (bands_counted & BIT(req->channels[i]->band))
 687                                         continue;
 688                                 bands_counted |= BIT(req->channels[i]->band);
 689                                 n_bands++;
 690                         }
 691
 692                         local->hw_scan_ies_bufsize *= n_bands;
 693                 }
 694
 695                 local->hw_scan_req = kmalloc(
 696                                 sizeof(*local->hw_scan_req) +
 697                                 req->n_channels * sizeof(req->channels[0]) +
 698                                 local->hw_scan_ies_bufsize, GFP_KERNEL);
 699                 if (!local->hw_scan_req)
 700                         return -ENOMEM;
 701
 702                 local->hw_scan_req->req.ssids = req->ssids;
 703                 local->hw_scan_req->req.n_ssids = req->n_ssids;
 704                 ies = (u8 *)local->hw_scan_req +
 705                         sizeof(*local->hw_scan_req) +
 706                         req->n_channels * sizeof(req->channels[0]);
 707                 local->hw_scan_req->req.ie = ies;
 708                 local->hw_scan_req->req.flags = req->flags;
 709                 eth_broadcast_addr(local->hw_scan_req->req.bssid);
 710                 local->hw_scan_req->req.duration = req->duration;
 711                 local->hw_scan_req->req.duration_mandatory =
 712                         req->duration_mandatory;
 713
 714                 local->hw_scan_band = 0;
 715
 716                 /*
 717                  * After allocating local->hw_scan_req, we must
 718                  * go through until ieee80211_prep_hw_scan(), so
 719                  * anything that might be changed here and leave
 720                  * this function early must not go after this
 721                  * allocation.
 722                  */
 723         }
 724
 725         rcu_assign_pointer(local->scan_req, req);
 726         rcu_assign_pointer(local->scan_sdata, sdata);
 727
 728         if (req->flags & NL80211_SCAN_FLAG_RANDOM_ADDR)
 729                 get_random_mask_addr(local->scan_addr,
 730                                      req->mac_addr,
 731                                      req->mac_addr_mask);
 732         else
 733                 memcpy(local->scan_addr, sdata->vif.addr, ETH_ALEN);
 734
 735         if (hw_scan) {
 736                 __set_bit(SCAN_HW_SCANNING, &local->scanning);
 737         } else if ((req->n_channels == 1) &&
 738                    (req->channels[0] == local->_oper_chandef.chan)) {
 739                 /*
 740                  * If we are scanning only on the operating channel
 741                  * then we do not need to stop normal activities
 742                  */
 743                 unsigned long next_delay;
 744
 745                 __set_bit(SCAN_ONCHANNEL_SCANNING, &local->scanning);
 746
 747                 ieee80211_recalc_idle(local);
 748
 749                 /* Notify driver scan is starting, keep order of operations
 750                  * same as normal software scan, in case that matters. */
 751                 drv_sw_scan_start(local, sdata, local->scan_addr);
 752
 753                 ieee80211_configure_filter(local); /* accept probe-responses */
 754
 755                 /* We need to ensure power level is at max for scanning. */
 756                 ieee80211_hw_config(local, 0);
 757
 758                 if ((req->channels[0]->flags & (IEEE80211_CHAN_NO_IR |
 759                                                 IEEE80211_CHAN_RADAR)) ||
 760                     !req->n_ssids) {
 761                         next_delay = IEEE80211_PASSIVE_CHANNEL_TIME;
 762                 } else {
 763                         ieee80211_scan_state_send_probe(local, &next_delay);
 764                         next_delay = IEEE80211_CHANNEL_TIME;
 765                 }
 766
 767                 /* Now, just wait a bit and we are all done! */
 768                 ieee80211_queue_delayed_work(&local->hw, &local->scan_work,
 769                                              next_delay);
 770                 return 0;
 771         } else {
 772                 /* Do normal software scan */
 773                 __set_bit(SCAN_SW_SCANNING, &local->scanning);
 774         }
 775
 776         ieee80211_recalc_idle(local);
 777
 778         if (hw_scan) {
 779                 WARN_ON(!ieee80211_prep_hw_scan(sdata));
 780                 rc = drv_hw_scan(local, sdata, local->hw_scan_req);
 781         } else {
 782                 rc = ieee80211_start_sw_scan(local, sdata);
 783         }
 784
 785         if (rc) {
 786                 kfree(local->hw_scan_req);
 787                 local->hw_scan_req = NULL;
 788                 local->scanning = 0;
 789
 790                 ieee80211_recalc_idle(local);
 791
 792                 local->scan_req = NULL;
 793                 RCU_INIT_POINTER(local->scan_sdata, NULL);
 794         }
 795
 796         if (hw_scan && rc == 1) {
 797                 /*
 798                  * we can't fall back to software for P2P-GO
 799                  * as it must update NoA etc.
 800                  */
 801                 if (ieee80211_vif_type_p2p(&sdata->vif) ==
 802                                 NL80211_IFTYPE_P2P_GO)
 803                         return -EOPNOTSUPP;
 804                 hw_scan = false;
 805                 goto again;
 806         }
 807
 808         return rc;
 809 }
 810
 811 static unsigned long
 812 ieee80211_scan_get_channel_time(struct ieee80211_channel *chan)
 813 {
 814         /*
 815          * TODO: channel switching also consumes quite some time,
 816          * add that delay as well to get a better estimation
 817          */
 818         if (chan->flags & (IEEE80211_CHAN_NO_IR | IEEE80211_CHAN_RADAR))
 819                 return IEEE80211_PASSIVE_CHANNEL_TIME;
 820         return IEEE80211_PROBE_DELAY + IEEE80211_CHANNEL_TIME;
 821 }
 822
 823 static void ieee80211_scan_state_decision(struct ieee80211_local *local,
 824                                           unsigned long *next_delay)
 825 {
 826         bool associated = false;
 827         bool tx_empty = true;
 828         bool bad_latency;
 829         struct ieee80211_sub_if_data *sdata;
 830         struct ieee80211_channel *next_chan;
 831         enum mac80211_scan_state next_scan_state;
 832         struct cfg80211_scan_request *scan_req;
 833
 834         /*
 835          * check if at least one STA interface is associated,
 836          * check if at least one STA interface has pending tx frames
 837          * and grab the lowest used beacon interval
 838          */
 839         mutex_lock(&local->iflist_mtx);
 840         list_for_each_entry(sdata, &local->interfaces, list) {
 841                 if (!ieee80211_sdata_running(sdata))
 842                         continue;
 843
 844                 if (sdata->vif.type == NL80211_IFTYPE_STATION) {
 845                         if (sdata->u.mgd.associated) {
 846                                 associated = true;
 847
 848                                 if (!qdisc_all_tx_empty(sdata->dev)) {
 849                                         tx_empty = false;
 850                                         break;
 851                                 }
 852                         }
 853                 }
 854         }
 855         mutex_unlock(&local->iflist_mtx);
 856
 857         scan_req = rcu_dereference_protected(local->scan_req,
 858                                              lockdep_is_held(&local->mtx));
 859
 860         next_chan = scan_req->channels[local->scan_channel_idx];
 861
 862         /*
 863          * we're currently scanning a different channel, let's
 864          * see if we can scan another channel without interfering
 865          * with the current traffic situation.
 866          *
 867          * Keep good latency, do not stay off-channel more than 125 ms.
 868          */
 869
 870         bad_latency = time_after(jiffies +
 871                                  ieee80211_scan_get_channel_time(next_chan),
 872                                  local->leave_oper_channel_time + HZ / 8);
 873
 874         if (associated && !tx_empty) {
 875                 if (scan_req->flags & NL80211_SCAN_FLAG_LOW_PRIORITY)
 876                         next_scan_state = SCAN_ABORT;
 877                 else
 878                         next_scan_state = SCAN_SUSPEND;
 879         } else if (associated && bad_latency) {
 880                 next_scan_state = SCAN_SUSPEND;
 881         } else {
 882                 next_scan_state = SCAN_SET_CHANNEL;
 883         }
 884
 885         local->next_scan_state = next_scan_state;
 886
 887         *next_delay = 0;
 888 }
 889
 890 static void ieee80211_scan_state_set_channel(struct ieee80211_local *local,
 891                                              unsigned long *next_delay)
 892 {
 893         int skip;
 894         struct ieee80211_channel *chan;
 895         enum nl80211_bss_scan_width oper_scan_width;
 896         struct cfg80211_scan_request *scan_req;
 897
 898         scan_req = rcu_dereference_protected(local->scan_req,
 899                                              lockdep_is_held(&local->mtx));
 900
 901         skip = 0;
 902         chan = scan_req->channels[local->scan_channel_idx];
 903
 904         local->scan_chandef.chan = chan;
 905         local->scan_chandef.center_freq1 = chan->center_freq;
 906         local->scan_chandef.freq1_offset = chan->freq_offset;
 907         local->scan_chandef.center_freq2 = 0;
 908         switch (scan_req->scan_width) {
 909         case NL80211_BSS_CHAN_WIDTH_5:
 910                 local->scan_chandef.width = NL80211_CHAN_WIDTH_5;
 911                 break;
 912         case NL80211_BSS_CHAN_WIDTH_10:
 913                 local->scan_chandef.width = NL80211_CHAN_WIDTH_10;
 914                 break;
 915         default:
 916         case NL80211_BSS_CHAN_WIDTH_20:
 917                 /* If scanning on oper channel, use whatever channel-type
 918                  * is currently in use.
 919                  */
 920                 oper_scan_width = cfg80211_chandef_to_scan_width(
 921                                         &local->_oper_chandef);
 922                 if (chan == local->_oper_chandef.chan &&
 923                     oper_scan_width == scan_req->scan_width)
 924                         local->scan_chandef = local->_oper_chandef;
 925                 else
 926                         local->scan_chandef.width = NL80211_CHAN_WIDTH_20_NOHT;
 927                 break;
 928         }
 929
 930         if (ieee80211_hw_config(local, IEEE80211_CONF_CHANGE_CHANNEL))
 931                 skip = 1;
 932
 933         /* advance state machine to next channel/band */
 934         local->scan_channel_idx++;
 935
 936         if (skip) {
 937                 /* if we skip this channel return to the decision state */
 938                 local->next_scan_state = SCAN_DECISION;
 939                 return;
 940         }
 941
 942         /*
 943          * Probe delay is used to update the NAV, cf. 11.1.3.2.2
 944          * (which unfortunately doesn't say _why_ step a) is done,
 945          * but it waits for the probe delay or until a frame is
 946          * received - and the received frame would update the NAV).
 947          * For now, we do not support waiting until a frame is
 948          * received.
 949          *
 950          * In any case, it is not necessary for a passive scan.
 951          */
 952         if ((chan->flags & (IEEE80211_CHAN_NO_IR | IEEE80211_CHAN_RADAR)) ||
 953             !scan_req->n_ssids) {
 954                 *next_delay = IEEE80211_PASSIVE_CHANNEL_TIME;
 955                 local->next_scan_state = SCAN_DECISION;
 956                 return;
 957         }
 958
 959         /* active scan, send probes */
 960         *next_delay = IEEE80211_PROBE_DELAY;
 961         local->next_scan_state = SCAN_SEND_PROBE;
 962 }
 963
 964 static void ieee80211_scan_state_suspend(struct ieee80211_local *local,
 965                                          unsigned long *next_delay)
 966 {
 967         /* switch back to the operating channel */
 968         local->scan_chandef.chan = NULL;
 969         ieee80211_hw_config(local, IEEE80211_CONF_CHANGE_CHANNEL);
 970
 971         /* disable PS */
 972         ieee80211_offchannel_return(local);
 973
 974         *next_delay = HZ / 5;
 975         /* afterwards, resume scan & go to next channel */
 976         local->next_scan_state = SCAN_RESUME;
 977 }
 978
 979 static void ieee80211_scan_state_resume(struct ieee80211_local *local,
 980                                         unsigned long *next_delay)
 981 {
 982         ieee80211_offchannel_stop_vifs(local);
 983
 984         if (local->ops->flush) {
 985                 ieee80211_flush_queues(local, NULL, false);
 986                 *next_delay = 0;
 987         } else
 988                 *next_delay = HZ / 10;
 989
 990         /* remember when we left the operating channel */
 991         local->leave_oper_channel_time = jiffies;
 992
 993         /* advance to the next channel to be scanned */
 994         local->next_scan_state = SCAN_SET_CHANNEL;
 995 }
 996
 997 void ieee80211_scan_work(struct work_struct *work)
 998 {
 999         struct ieee80211_local *local =
1000                 container_of(work, struct ieee80211_local, scan_work.work);
1001         struct ieee80211_sub_if_data *sdata;
1002         struct cfg80211_scan_request *scan_req;
1003         unsigned long next_delay = 0;
1004         bool aborted;
1005
1006         mutex_lock(&local->mtx);
1007
1008         if (!ieee80211_can_run_worker(local)) {
1009                 aborted = true;
1010                 goto out_complete;
1011         }
1012
1013         sdata = rcu_dereference_protected(local->scan_sdata,
1014                                           lockdep_is_held(&local->mtx));
1015         scan_req = rcu_dereference_protected(local->scan_req,
1016                                              lockdep_is_held(&local->mtx));
1017
1018         /* When scanning on-channel, the first-callback means completed. */
1019         if (test_bit(SCAN_ONCHANNEL_SCANNING, &local->scanning)) {
1020                 aborted = test_and_clear_bit(SCAN_ABORTED, &local->scanning);
1021                 goto out_complete;
1022         }
1023
1024         if (test_and_clear_bit(SCAN_COMPLETED, &local->scanning)) {
1025                 aborted = test_and_clear_bit(SCAN_ABORTED, &local->scanning);
1026                 goto out_complete;
1027         }
1028
1029         if (!sdata || !scan_req)
1030                 goto out;
1031
1032         if (!local->scanning) {
1033                 int rc;
1034
1035                 RCU_INIT_POINTER(local->scan_req, NULL);
1036                 RCU_INIT_POINTER(local->scan_sdata, NULL);
1037
1038                 rc = __ieee80211_start_scan(sdata, scan_req);
1039                 if (rc) {
1040                         /* need to complete scan in cfg80211 */
1041                         rcu_assign_pointer(local->scan_req, scan_req);
1042                         aborted = true;
1043                         goto out_complete;
1044                 } else
1045                         goto out;
1046         }
1047
1048         /*
1049          * as long as no delay is required advance immediately
1050          * without scheduling a new work
1051          */
1052         do {
1053                 if (!ieee80211_sdata_running(sdata)) {
1054                         aborted = true;
1055                         goto out_complete;
1056                 }
1057
1058                 switch (local->next_scan_state) {
1059                 case SCAN_DECISION:
1060                         /* if no more bands/channels left, complete scan */
1061                         if (local->scan_channel_idx >= scan_req->n_channels) {
1062                                 aborted = false;
1063                                 goto out_complete;
1064                         }
1065                         ieee80211_scan_state_decision(local, &next_delay);
1066                         break;
1067                 case SCAN_SET_CHANNEL:
1068                         ieee80211_scan_state_set_channel(local, &next_delay);
1069                         break;
1070                 case SCAN_SEND_PROBE:
1071                         ieee80211_scan_state_send_probe(local, &next_delay);
1072                         break;
1073                 case SCAN_SUSPEND:
1074                         ieee80211_scan_state_suspend(local, &next_delay);
1075                         break;
1076                 case SCAN_RESUME:
1077                         ieee80211_scan_state_resume(local, &next_delay);
1078                         break;
1079                 case SCAN_ABORT:
1080                         aborted = true;
1081                         goto out_complete;
1082                 }
1083         } while (next_delay == 0);
1084
1085         ieee80211_queue_delayed_work(&local->hw, &local->scan_work, next_delay);
1086         goto out;
1087
1088 out_complete:
1089         __ieee80211_scan_completed(&local->hw, aborted);
1090 out:
1091         mutex_unlock(&local->mtx);
1092 }
1093
1094 int ieee80211_request_scan(struct ieee80211_sub_if_data *sdata,
1095                            struct cfg80211_scan_request *req)
1096 {
1097         int res;
1098
1099         mutex_lock(&sdata->local->mtx);
1100         res = __ieee80211_start_scan(sdata, req);
1101         mutex_unlock(&sdata->local->mtx);
1102
1103         return res;
1104 }
1105
1106 int ieee80211_request_ibss_scan(struct ieee80211_sub_if_data *sdata,
1107                                 const u8 *ssid, u8 ssid_len,
1108                                 struct ieee80211_channel **channels,
1109                                 unsigned int n_channels,
1110                                 enum nl80211_bss_scan_width scan_width)
1111 {
1112         struct ieee80211_local *local = sdata->local;
1113         int ret = -EBUSY, i, n_ch = 0;
1114         enum nl80211_band band;
1115
1116         mutex_lock(&local->mtx);
1117
1118         /* busy scanning */
1119         if (local->scan_req)
1120                 goto unlock;
1121
1122         /* fill internal scan request */
1123         if (!channels) {
1124                 int max_n;
1125
1126                 for (band = 0; band < NUM_NL80211_BANDS; band++) {
1127                         if (!local->hw.wiphy->bands[band])
1128                                 continue;
1129
1130                         max_n = local->hw.wiphy->bands[band]->n_channels;
1131                         for (i = 0; i < max_n; i++) {
1132                                 struct ieee80211_channel *tmp_ch =
1133                                     &local->hw.wiphy->bands[band]->channels[i];
1134
1135                                 if (tmp_ch->flags & (IEEE80211_CHAN_NO_IR |
1136                                                      IEEE80211_CHAN_DISABLED))
1137                                         continue;
1138
1139                                 local->int_scan_req->channels[n_ch] = tmp_ch;
1140                                 n_ch++;
1141                         }
1142                 }
1143
1144                 if (WARN_ON_ONCE(n_ch == 0))
1145                         goto unlock;
1146
1147                 local->int_scan_req->n_channels = n_ch;
1148         } else {
1149                 for (i = 0; i < n_channels; i++) {
1150                         if (channels[i]->flags & (IEEE80211_CHAN_NO_IR |
1151                                                   IEEE80211_CHAN_DISABLED))
1152                                 continue;
1153
1154                         local->int_scan_req->channels[n_ch] = channels[i];
1155                         n_ch++;
1156                 }
1157
1158                 if (WARN_ON_ONCE(n_ch == 0))
1159                         goto unlock;
1160
1161                 local->int_scan_req->n_channels = n_ch;
1162         }
1163
1164         local->int_scan_req->ssids = &local->scan_ssid;
1165         local->int_scan_req->n_ssids = 1;
1166         local->int_scan_req->scan_width = scan_width;
1167         memcpy(local->int_scan_req->ssids[0].ssid, ssid, IEEE80211_MAX_SSID_LEN);
1168         local->int_scan_req->ssids[0].ssid_len = ssid_len;
1169
1170         ret = __ieee80211_start_scan(sdata, sdata->local->int_scan_req);
1171  unlock:
1172         mutex_unlock(&local->mtx);
1173         return ret;
1174 }
1175
1176 /*
1177  * Only call this function when a scan can't be queued -- under RTNL.
1178  */
1179 void ieee80211_scan_cancel(struct ieee80211_local *local)
1180 {
1181         /*
1182          * We are canceling software scan, or deferred scan that was not
1183          * yet really started (see __ieee80211_start_scan ).
1184          *
1185          * Regarding hardware scan:
1186          * - we can not call  __ieee80211_scan_completed() as when
1187          *   SCAN_HW_SCANNING bit is set this function change
1188          *   local->hw_scan_req to operate on 5G band, what race with
1189          *   driver which can use local->hw_scan_req
1190          *
1191          * - we can not cancel scan_work since driver can schedule it
1192          *   by ieee80211_scan_completed(..., true) to finish scan
1193          *
1194          * Hence we only call the cancel_hw_scan() callback, but the low-level
1195          * driver is still responsible for calling ieee80211_scan_completed()
1196          * after the scan was completed/aborted.
1197          */
1198
1199         mutex_lock(&local->mtx);
1200         if (!local->scan_req)
1201                 goto out;
1202
1203         /*
1204          * We have a scan running and the driver already reported completion,
1205          * but the worker hasn't run yet or is stuck on the mutex - mark it as
1206          * cancelled.
1207          */
1208         if (test_bit(SCAN_HW_SCANNING, &local->scanning) &&
1209             test_bit(SCAN_COMPLETED, &local->scanning)) {
1210                 set_bit(SCAN_HW_CANCELLED, &local->scanning);
1211                 goto out;
1212         }
1213
1214         if (test_bit(SCAN_HW_SCANNING, &local->scanning)) {
1215                 /*
1216                  * Make sure that __ieee80211_scan_completed doesn't trigger a
1217                  * scan on another band.
1218                  */
1219                 set_bit(SCAN_HW_CANCELLED, &local->scanning);
1220                 if (local->ops->cancel_hw_scan)
1221                         drv_cancel_hw_scan(local,
1222                                 rcu_dereference_protected(local->scan_sdata,
1223                                                 lockdep_is_held(&local->mtx)));
1224                 goto out;
1225         }
1226
1227         /*
1228          * If the work is currently running, it must be blocked on
1229          * the mutex, but we'll set scan_sdata = NULL and it'll
1230          * simply exit once it acquires the mutex.
1231          */
1232         cancel_delayed_work(&local->scan_work);
1233         /* and clean up */
1234         memset(&local->scan_info, 0, sizeof(local->scan_info));
1235         __ieee80211_scan_completed(&local->hw, true);
1236 out:
1237         mutex_unlock(&local->mtx);
1238 }
1239
1240 int __ieee80211_request_sched_scan_start(struct ieee80211_sub_if_data *sdata,
1241                                         struct cfg80211_sched_scan_request *req)
1242 {
1243         struct ieee80211_local *local = sdata->local;
1244         struct ieee80211_scan_ies sched_scan_ies = {};
1245         struct cfg80211_chan_def chandef;
1246         int ret, i, iebufsz, num_bands = 0;
1247         u32 rate_masks[NUM_NL80211_BANDS] = {};
1248         u8 bands_used = 0;
1249         u8 *ie;
1250         u32 flags = 0;
1251
1252         iebufsz = local->scan_ies_len + req->ie_len;
1253
1254         lockdep_assert_held(&local->mtx);
1255
1256         if (!local->ops->sched_scan_start)
1257                 return -ENOTSUPP;
1258
1259         for (i = 0; i < NUM_NL80211_BANDS; i++) {
1260                 if (local->hw.wiphy->bands[i]) {
1261                         bands_used |= BIT(i);
1262                         rate_masks[i] = (u32) -1;
1263                         num_bands++;
1264                 }
1265         }
1266
1267         if (req->flags & NL80211_SCAN_FLAG_MIN_PREQ_CONTENT)
1268                 flags |= IEEE80211_PROBE_FLAG_MIN_CONTENT;
1269
1270         ie = kcalloc(iebufsz, num_bands, GFP_KERNEL);
1271         if (!ie) {
1272                 ret = -ENOMEM;
1273                 goto out;
1274         }
1275
1276         ieee80211_prepare_scan_chandef(&chandef, req->scan_width);
1277
1278         ieee80211_build_preq_ies(sdata, ie, num_bands * iebufsz,
1279                                  &sched_scan_ies, req->ie,
1280                                  req->ie_len, bands_used, rate_masks, &chandef,
1281                                  flags);
1282
1283         ret = drv_sched_scan_start(local, sdata, req, &sched_scan_ies);
1284         if (ret == 0) {
1285                 rcu_assign_pointer(local->sched_scan_sdata, sdata);
1286                 rcu_assign_pointer(local->sched_scan_req, req);
1287         }
1288
1289         kfree(ie);
1290
1291 out:
1292         if (ret) {
1293                 /* Clean in case of failure after HW restart or upon resume. */
1294                 RCU_INIT_POINTER(local->sched_scan_sdata, NULL);
1295                 RCU_INIT_POINTER(local->sched_scan_req, NULL);
1296         }
1297
1298         return ret;
1299 }
1300
1301 int ieee80211_request_sched_scan_start(struct ieee80211_sub_if_data *sdata,
1302                                        struct cfg80211_sched_scan_request *req)
1303 {
1304         struct ieee80211_local *local = sdata->local;
1305         int ret;
1306
1307         mutex_lock(&local->mtx);
1308
1309         if (rcu_access_pointer(local->sched_scan_sdata)) {
1310                 mutex_unlock(&local->mtx);
1311                 return -EBUSY;
1312         }
1313
1314         ret = __ieee80211_request_sched_scan_start(sdata, req);
1315
1316         mutex_unlock(&local->mtx);
1317         return ret;
1318 }
1319
1320 int ieee80211_request_sched_scan_stop(struct ieee80211_local *local)
1321 {
1322         struct ieee80211_sub_if_data *sched_scan_sdata;
1323         int ret = -ENOENT;
1324
1325         mutex_lock(&local->mtx);
1326
1327         if (!local->ops->sched_scan_stop) {
1328                 ret = -ENOTSUPP;
1329                 goto out;
1330         }
1331
1332         /* We don't want to restart sched scan anymore. */
1333         RCU_INIT_POINTER(local->sched_scan_req, NULL);
1334
1335         sched_scan_sdata = rcu_dereference_protected(local->sched_scan_sdata,
1336                                                 lockdep_is_held(&local->mtx));
1337         if (sched_scan_sdata) {
1338                 ret = drv_sched_scan_stop(local, sched_scan_sdata);
1339                 if (!ret)
1340                         RCU_INIT_POINTER(local->sched_scan_sdata, NULL);
1341         }
1342 out:
1343         mutex_unlock(&local->mtx);
1344
1345         return ret;
1346 }
1347
1348 void ieee80211_sched_scan_results(struct ieee80211_hw *hw)
1349 {
1350         struct ieee80211_local *local = hw_to_local(hw);
1351
1352         trace_api_sched_scan_results(local);
1353
1354         cfg80211_sched_scan_results(hw->wiphy, 0);
1355 }
1356 EXPORT_SYMBOL(ieee80211_sched_scan_results);
1357
1358 void ieee80211_sched_scan_end(struct ieee80211_local *local)
1359 {
1360         mutex_lock(&local->mtx);
1361
1362         if (!rcu_access_pointer(local->sched_scan_sdata)) {
1363                 mutex_unlock(&local->mtx);
1364                 return;
1365         }
1366
1367         RCU_INIT_POINTER(local->sched_scan_sdata, NULL);
1368
1369         /* If sched scan was aborted by the driver. */
1370         RCU_INIT_POINTER(local->sched_scan_req, NULL);
1371
1372         mutex_unlock(&local->mtx);
1373
1374         cfg80211_sched_scan_stopped(local->hw.wiphy, 0);
1375 }
1376
1377 void ieee80211_sched_scan_stopped_work(struct work_struct *work)
1378 {
1379         struct ieee80211_local *local =
1380                 container_of(work, struct ieee80211_local,
1381                              sched_scan_stopped_work);
1382
1383         ieee80211_sched_scan_end(local);
1384 }
1385
1386 void ieee80211_sched_scan_stopped(struct ieee80211_hw *hw)
1387 {
1388         struct ieee80211_local *local = hw_to_local(hw);
1389
1390         trace_api_sched_scan_stopped(local);
1391
1392         /*
1393          * this shouldn't really happen, so for simplicity
1394          * simply ignore it, and let mac80211 reconfigure
1395          * the sched scan later on.
1396          */
1397         if (local->in_reconfig)
1398                 return;
1399
1400         schedule_work(&local->sched_scan_stopped_work);
1401 }
1402 EXPORT_SYMBOL(ieee80211_sched_scan_stopped);