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
 137 struct ieee80211_bss *
 138 ieee80211_bss_info_update(struct ieee80211_local *local,
 139                           struct ieee80211_rx_status *rx_status,
 140                           struct ieee80211_mgmt *mgmt, size_t len,
 141                           struct ieee80211_channel *channel)
 142 {
 143         bool beacon = ieee80211_is_beacon(mgmt->frame_control);
 144         struct cfg80211_bss *cbss, *non_tx_cbss;
 145         struct ieee80211_bss *bss, *non_tx_bss;
 146         struct cfg80211_inform_bss bss_meta = {
 147                 .boottime_ns = rx_status->boottime_ns,
 148         };
 149         bool signal_valid;
 150         struct ieee80211_sub_if_data *scan_sdata;
 151         struct ieee802_11_elems elems;
 152         size_t baselen;
 153         u8 *elements;
 154
 155         if (rx_status->flag & RX_FLAG_NO_SIGNAL_VAL)
 156                 bss_meta.signal = 0; /* invalid signal indication */
 157         else if (ieee80211_hw_check(&local->hw, SIGNAL_DBM))
 158                 bss_meta.signal = rx_status->signal * 100;
 159         else if (ieee80211_hw_check(&local->hw, SIGNAL_UNSPEC))
 160                 bss_meta.signal = (rx_status->signal * 100) / local->hw.max_signal;
 161
 162         bss_meta.scan_width = NL80211_BSS_CHAN_WIDTH_20;
 163         if (rx_status->bw == RATE_INFO_BW_5)
 164                 bss_meta.scan_width = NL80211_BSS_CHAN_WIDTH_5;
 165         else if (rx_status->bw == RATE_INFO_BW_10)
 166                 bss_meta.scan_width = NL80211_BSS_CHAN_WIDTH_10;
 167
 168         bss_meta.chan = channel;
 169
 170         rcu_read_lock();
 171         scan_sdata = rcu_dereference(local->scan_sdata);
 172         if (scan_sdata && scan_sdata->vif.type == NL80211_IFTYPE_STATION &&
 173             scan_sdata->vif.bss_conf.assoc &&
 174             ieee80211_have_rx_timestamp(rx_status)) {
 175                 bss_meta.parent_tsf =
 176                         ieee80211_calculate_rx_timestamp(local, rx_status,
 177                                                          len + FCS_LEN, 24);
 178                 ether_addr_copy(bss_meta.parent_bssid,
 179                                 scan_sdata->vif.bss_conf.bssid);
 180         }
 181         rcu_read_unlock();
 182
 183         cbss = cfg80211_inform_bss_frame_data(local->hw.wiphy, &bss_meta,
 184                                               mgmt, len, GFP_ATOMIC);
 185         if (!cbss)
 186                 return NULL;
 187
 188         if (ieee80211_is_probe_resp(mgmt->frame_control)) {
 189                 elements = mgmt->u.probe_resp.variable;
 190                 baselen = offsetof(struct ieee80211_mgmt,
 191                                    u.probe_resp.variable);
 192         } else {
 193                 baselen = offsetof(struct ieee80211_mgmt, u.beacon.variable);
 194                 elements = mgmt->u.beacon.variable;
 195         }
 196
 197         if (baselen > len)
 198                 return NULL;
 199
 200         ieee802_11_parse_elems(elements, len - baselen, false, &elems,
 201                                mgmt->bssid, cbss->bssid);
 202
 203         /* In case the signal is invalid update the status */
 204         signal_valid = abs(channel->center_freq - cbss->channel->center_freq)
 205                 <= local->hw.wiphy->max_adj_channel_rssi_comp;
 206         if (!signal_valid)
 207                 rx_status->flag |= RX_FLAG_NO_SIGNAL_VAL;
 208
 209         bss = (void *)cbss->priv;
 210         ieee80211_update_bss_from_elems(local, bss, &elems, rx_status, beacon);
 211
 212         list_for_each_entry(non_tx_cbss, &cbss->nontrans_list, nontrans_list) {
 213                 non_tx_bss = (void *)non_tx_cbss->priv;
 214
 215                 ieee80211_update_bss_from_elems(local, non_tx_bss, &elems,
 216                                                 rx_status, beacon);
 217         }
 218
 219         return bss;
 220 }
 221
 222 static bool ieee80211_scan_accept_presp(struct ieee80211_sub_if_data *sdata,
 223                                         u32 scan_flags, const u8 *da)
 224 {
 225         if (!sdata)
 226                 return false;
 227         /* accept broadcast for OCE */
 228         if (scan_flags & NL80211_SCAN_FLAG_ACCEPT_BCAST_PROBE_RESP &&
 229             is_broadcast_ether_addr(da))
 230                 return true;
 231         if (scan_flags & NL80211_SCAN_FLAG_RANDOM_ADDR)
 232                 return true;
 233         return ether_addr_equal(da, sdata->vif.addr);
 234 }
 235
 236 void ieee80211_scan_rx(struct ieee80211_local *local, struct sk_buff *skb)
 237 {
 238         struct ieee80211_rx_status *rx_status = IEEE80211_SKB_RXCB(skb);
 239         struct ieee80211_sub_if_data *sdata1, *sdata2;
 240         struct ieee80211_mgmt *mgmt = (void *)skb->data;
 241         struct ieee80211_bss *bss;
 242         struct ieee80211_channel *channel;
 243
 244         if (skb->len < 24 ||
 245             (!ieee80211_is_probe_resp(mgmt->frame_control) &&
 246              !ieee80211_is_beacon(mgmt->frame_control)))
 247                 return;
 248
 249         sdata1 = rcu_dereference(local->scan_sdata);
 250         sdata2 = rcu_dereference(local->sched_scan_sdata);
 251
 252         if (likely(!sdata1 && !sdata2))
 253                 return;
 254
 255         if (test_and_clear_bit(SCAN_BEACON_WAIT, &local->scanning)) {
 256                 /*
 257                  * we were passive scanning because of radar/no-IR, but
 258                  * the beacon/proberesp rx gives us an opportunity to upgrade
 259                  * to active scan
 260                  */
 261                  set_bit(SCAN_BEACON_DONE, &local->scanning);
 262                  ieee80211_queue_delayed_work(&local->hw, &local->scan_work, 0);
 263         }
 264
 265         if (ieee80211_is_probe_resp(mgmt->frame_control)) {
 266                 struct cfg80211_scan_request *scan_req;
 267                 struct cfg80211_sched_scan_request *sched_scan_req;
 268                 u32 scan_req_flags = 0, sched_scan_req_flags = 0;
 269
 270                 scan_req = rcu_dereference(local->scan_req);
 271                 sched_scan_req = rcu_dereference(local->sched_scan_req);
 272
 273                 if (scan_req)
 274                         scan_req_flags = scan_req->flags;
 275
 276                 if (sched_scan_req)
 277                         sched_scan_req_flags = sched_scan_req->flags;
 278
 279                 /* ignore ProbeResp to foreign address or non-bcast (OCE)
 280                  * unless scanning with randomised address
 281                  */
 282                 if (!ieee80211_scan_accept_presp(sdata1, scan_req_flags,
 283                                                  mgmt->da) &&
 284                     !ieee80211_scan_accept_presp(sdata2, sched_scan_req_flags,
 285                                                  mgmt->da))
 286                         return;
 287         }
 288
 289         channel = ieee80211_get_channel(local->hw.wiphy, rx_status->freq);
 290
 291         if (!channel || channel->flags & IEEE80211_CHAN_DISABLED)
 292                 return;
 293
 294         bss = ieee80211_bss_info_update(local, rx_status,
 295                                         mgmt, skb->len,
 296                                         channel);
 297         if (bss)
 298                 ieee80211_rx_bss_put(local, bss);
 299 }
 300
 301 static void
 302 ieee80211_prepare_scan_chandef(struct cfg80211_chan_def *chandef,
 303                                enum nl80211_bss_scan_width scan_width)
 304 {
 305         memset(chandef, 0, sizeof(*chandef));
 306         switch (scan_width) {
 307         case NL80211_BSS_CHAN_WIDTH_5:
 308                 chandef->width = NL80211_CHAN_WIDTH_5;
 309                 break;
 310         case NL80211_BSS_CHAN_WIDTH_10:
 311                 chandef->width = NL80211_CHAN_WIDTH_10;
 312                 break;
 313         default:
 314                 chandef->width = NL80211_CHAN_WIDTH_20_NOHT;
 315                 break;
 316         }
 317 }
 318
 319 /* return false if no more work */
 320 static bool ieee80211_prep_hw_scan(struct ieee80211_local *local)
 321 {
 322         struct cfg80211_scan_request *req;
 323         struct cfg80211_chan_def chandef;
 324         u8 bands_used = 0;
 325         int i, ielen, n_chans;
 326         u32 flags = 0;
 327
 328         req = rcu_dereference_protected(local->scan_req,
 329                                         lockdep_is_held(&local->mtx));
 330
 331         if (test_bit(SCAN_HW_CANCELLED, &local->scanning))
 332                 return false;
 333
 334         if (ieee80211_hw_check(&local->hw, SINGLE_SCAN_ON_ALL_BANDS)) {
 335                 for (i = 0; i < req->n_channels; i++) {
 336                         local->hw_scan_req->req.channels[i] = req->channels[i];
 337                         bands_used |= BIT(req->channels[i]->band);
 338                 }
 339
 340                 n_chans = req->n_channels;
 341         } else {
 342                 do {
 343                         if (local->hw_scan_band == NUM_NL80211_BANDS)
 344                                 return false;
 345
 346                         n_chans = 0;
 347
 348                         for (i = 0; i < req->n_channels; i++) {
 349                                 if (req->channels[i]->band !=
 350                                     local->hw_scan_band)
 351                                         continue;
 352                                 local->hw_scan_req->req.channels[n_chans] =
 353                                                         req->channels[i];
 354                                 n_chans++;
 355                                 bands_used |= BIT(req->channels[i]->band);
 356                         }
 357
 358                         local->hw_scan_band++;
 359                 } while (!n_chans);
 360         }
 361
 362         local->hw_scan_req->req.n_channels = n_chans;
 363         ieee80211_prepare_scan_chandef(&chandef, req->scan_width);
 364
 365         if (req->flags & NL80211_SCAN_FLAG_MIN_PREQ_CONTENT)
 366                 flags |= IEEE80211_PROBE_FLAG_MIN_CONTENT;
 367
 368         ielen = ieee80211_build_preq_ies(local,
 369                                          (u8 *)local->hw_scan_req->req.ie,
 370                                          local->hw_scan_ies_bufsize,
 371                                          &local->hw_scan_req->ies,
 372                                          req->ie, req->ie_len,
 373                                          bands_used, req->rates, &chandef,
 374                                          flags);
 375         local->hw_scan_req->req.ie_len = ielen;
 376         local->hw_scan_req->req.no_cck = req->no_cck;
 377         ether_addr_copy(local->hw_scan_req->req.mac_addr, req->mac_addr);
 378         ether_addr_copy(local->hw_scan_req->req.mac_addr_mask,
 379                         req->mac_addr_mask);
 380         ether_addr_copy(local->hw_scan_req->req.bssid, req->bssid);
 381
 382         return true;
 383 }
 384
 385 static void __ieee80211_scan_completed(struct ieee80211_hw *hw, bool aborted)
 386 {
 387         struct ieee80211_local *local = hw_to_local(hw);
 388         bool hw_scan = test_bit(SCAN_HW_SCANNING, &local->scanning);
 389         bool was_scanning = local->scanning;
 390         struct cfg80211_scan_request *scan_req;
 391         struct ieee80211_sub_if_data *scan_sdata;
 392         struct ieee80211_sub_if_data *sdata;
 393
 394         lockdep_assert_held(&local->mtx);
 395
 396         /*
 397          * It's ok to abort a not-yet-running scan (that
 398          * we have one at all will be verified by checking
 399          * local->scan_req next), but not to complete it
 400          * successfully.
 401          */
 402         if (WARN_ON(!local->scanning && !aborted))
 403                 aborted = true;
 404
 405         if (WARN_ON(!local->scan_req))
 406                 return;
 407
 408         if (hw_scan && !aborted &&
 409             !ieee80211_hw_check(&local->hw, SINGLE_SCAN_ON_ALL_BANDS) &&
 410             ieee80211_prep_hw_scan(local)) {
 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
 440         scan_sdata = rcu_dereference_protected(local->scan_sdata,
 441                                                lockdep_is_held(&local->mtx));
 442         RCU_INIT_POINTER(local->scan_sdata, NULL);
 443
 444         local->scanning = 0;
 445         local->scan_chandef.chan = NULL;
 446
 447         /* Set power back to normal operating levels. */
 448         ieee80211_hw_config(local, 0);
 449
 450         if (!hw_scan) {
 451                 ieee80211_configure_filter(local);
 452                 drv_sw_scan_complete(local, scan_sdata);
 453                 ieee80211_offchannel_return(local);
 454         }
 455
 456         ieee80211_recalc_idle(local);
 457
 458         ieee80211_mlme_notify_scan_completed(local);
 459         ieee80211_ibss_notify_scan_completed(local);
 460
 461         /* Requeue all the work that might have been ignored while
 462          * the scan was in progress; if there was none this will
 463          * just be a no-op for the particular interface.
 464          */
 465         list_for_each_entry_rcu(sdata, &local->interfaces, list) {
 466                 if (ieee80211_sdata_running(sdata))
 467                         ieee80211_queue_work(&sdata->local->hw, &sdata->work);
 468         }
 469
 470         if (was_scanning)
 471                 ieee80211_start_next_roc(local);
 472 }
 473
 474 void ieee80211_scan_completed(struct ieee80211_hw *hw,
 475                               struct cfg80211_scan_info *info)
 476 {
 477         struct ieee80211_local *local = hw_to_local(hw);
 478
 479         trace_api_scan_completed(local, info->aborted);
 480
 481         set_bit(SCAN_COMPLETED, &local->scanning);
 482         if (info->aborted)
 483                 set_bit(SCAN_ABORTED, &local->scanning);
 484
 485         memcpy(&local->scan_info, info, sizeof(*info));
 486
 487         ieee80211_queue_delayed_work(&local->hw, &local->scan_work, 0);
 488 }
 489 EXPORT_SYMBOL(ieee80211_scan_completed);
 490
 491 static int ieee80211_start_sw_scan(struct ieee80211_local *local,
 492                                    struct ieee80211_sub_if_data *sdata)
 493 {
 494         /* Software scan is not supported in multi-channel cases */
 495         if (local->use_chanctx)
 496                 return -EOPNOTSUPP;
 497
 498         /*
 499          * Hardware/driver doesn't support hw_scan, so use software
 500          * scanning instead. First send a nullfunc frame with power save
 501          * bit on so that AP will buffer the frames for us while we are not
 502          * listening, then send probe requests to each channel and wait for
 503          * the responses. After all channels are scanned, tune back to the
 504          * original channel and send a nullfunc frame with power save bit
 505          * off to trigger the AP to send us all the buffered frames.
 506          *
 507          * Note that while local->sw_scanning is true everything else but
 508          * nullfunc frames and probe requests will be dropped in
 509          * ieee80211_tx_h_check_assoc().
 510          */
 511         drv_sw_scan_start(local, sdata, local->scan_addr);
 512
 513         local->leave_oper_channel_time = jiffies;
 514         local->next_scan_state = SCAN_DECISION;
 515         local->scan_channel_idx = 0;
 516
 517         ieee80211_offchannel_stop_vifs(local);
 518
 519         /* ensure nullfunc is transmitted before leaving operating channel */
 520         ieee80211_flush_queues(local, NULL, false);
 521
 522         ieee80211_configure_filter(local);
 523
 524         /* We need to set power level at maximum rate for scanning. */
 525         ieee80211_hw_config(local, 0);
 526
 527         ieee80211_queue_delayed_work(&local->hw,
 528                                      &local->scan_work, 0);
 529
 530         return 0;
 531 }
 532
 533 static bool __ieee80211_can_leave_ch(struct ieee80211_sub_if_data *sdata)
 534 {
 535         struct ieee80211_local *local = sdata->local;
 536         struct ieee80211_sub_if_data *sdata_iter;
 537
 538         if (!ieee80211_is_radar_required(local))
 539                 return true;
 540
 541         if (!regulatory_pre_cac_allowed(local->hw.wiphy))
 542                 return false;
 543
 544         mutex_lock(&local->iflist_mtx);
 545         list_for_each_entry(sdata_iter, &local->interfaces, list) {
 546                 if (sdata_iter->wdev.cac_started) {
 547                         mutex_unlock(&local->iflist_mtx);
 548                         return false;
 549                 }
 550         }
 551         mutex_unlock(&local->iflist_mtx);
 552
 553         return true;
 554 }
 555
 556 static bool ieee80211_can_scan(struct ieee80211_local *local,
 557                                struct ieee80211_sub_if_data *sdata)
 558 {
 559         if (!__ieee80211_can_leave_ch(sdata))
 560                 return false;
 561
 562         if (!list_empty(&local->roc_list))
 563                 return false;
 564
 565         if (sdata->vif.type == NL80211_IFTYPE_STATION &&
 566             sdata->u.mgd.flags & IEEE80211_STA_CONNECTION_POLL)
 567                 return false;
 568
 569         return true;
 570 }
 571
 572 void ieee80211_run_deferred_scan(struct ieee80211_local *local)
 573 {
 574         lockdep_assert_held(&local->mtx);
 575
 576         if (!local->scan_req || local->scanning)
 577                 return;
 578
 579         if (!ieee80211_can_scan(local,
 580                                 rcu_dereference_protected(
 581                                         local->scan_sdata,
 582                                         lockdep_is_held(&local->mtx))))
 583                 return;
 584
 585         ieee80211_queue_delayed_work(&local->hw, &local->scan_work,
 586                                      round_jiffies_relative(0));
 587 }
 588
 589 static void ieee80211_send_scan_probe_req(struct ieee80211_sub_if_data *sdata,
 590                                           const u8 *src, const u8 *dst,
 591                                           const u8 *ssid, size_t ssid_len,
 592                                           const u8 *ie, size_t ie_len,
 593                                           u32 ratemask, u32 flags, u32 tx_flags,
 594                                           struct ieee80211_channel *channel)
 595 {
 596         struct sk_buff *skb;
 597         u32 txdata_flags = 0;
 598
 599         skb = ieee80211_build_probe_req(sdata, src, dst, ratemask, channel,
 600                                         ssid, ssid_len,
 601                                         ie, ie_len, flags);
 602
 603         if (skb) {
 604                 if (flags & IEEE80211_PROBE_FLAG_RANDOM_SN) {
 605                         struct ieee80211_hdr *hdr = (void *)skb->data;
 606                         u16 sn = get_random_u32();
 607
 608                         txdata_flags |= IEEE80211_TX_NO_SEQNO;
 609                         hdr->seq_ctrl =
 610                                 cpu_to_le16(IEEE80211_SN_TO_SEQ(sn));
 611                 }
 612                 IEEE80211_SKB_CB(skb)->flags |= tx_flags;
 613                 ieee80211_tx_skb_tid_band(sdata, skb, 7, channel->band,
 614                                           txdata_flags);
 615         }
 616 }
 617
 618 static void ieee80211_scan_state_send_probe(struct ieee80211_local *local,
 619                                             unsigned long *next_delay)
 620 {
 621         int i;
 622         struct ieee80211_sub_if_data *sdata;
 623         struct cfg80211_scan_request *scan_req;
 624         enum nl80211_band band = local->hw.conf.chandef.chan->band;
 625         u32 flags = 0, tx_flags;
 626
 627         scan_req = rcu_dereference_protected(local->scan_req,
 628                                              lockdep_is_held(&local->mtx));
 629
 630         tx_flags = IEEE80211_TX_INTFL_OFFCHAN_TX_OK;
 631         if (scan_req->no_cck)
 632                 tx_flags |= IEEE80211_TX_CTL_NO_CCK_RATE;
 633         if (scan_req->flags & NL80211_SCAN_FLAG_MIN_PREQ_CONTENT)
 634                 flags |= IEEE80211_PROBE_FLAG_MIN_CONTENT;
 635         if (scan_req->flags & NL80211_SCAN_FLAG_RANDOM_SN)
 636                 flags |= IEEE80211_PROBE_FLAG_RANDOM_SN;
 637
 638         sdata = rcu_dereference_protected(local->scan_sdata,
 639                                           lockdep_is_held(&local->mtx));
 640
 641         for (i = 0; i < scan_req->n_ssids; i++)
 642                 ieee80211_send_scan_probe_req(
 643                         sdata, local->scan_addr, scan_req->bssid,
 644                         scan_req->ssids[i].ssid, scan_req->ssids[i].ssid_len,
 645                         scan_req->ie, scan_req->ie_len,
 646                         scan_req->rates[band], flags,
 647                         tx_flags, local->hw.conf.chandef.chan);
 648
 649         /*
 650          * After sending probe requests, wait for probe responses
 651          * on the channel.
 652          */
 653         *next_delay = IEEE80211_CHANNEL_TIME;
 654         local->next_scan_state = SCAN_DECISION;
 655 }
 656
 657 static int __ieee80211_start_scan(struct ieee80211_sub_if_data *sdata,
 658                                   struct cfg80211_scan_request *req)
 659 {
 660         struct ieee80211_local *local = sdata->local;
 661         bool hw_scan = local->ops->hw_scan;
 662         int rc;
 663
 664         lockdep_assert_held(&local->mtx);
 665
 666         if (local->scan_req)
 667                 return -EBUSY;
 668
 669         if (!__ieee80211_can_leave_ch(sdata))
 670                 return -EBUSY;
 671
 672         if (!ieee80211_can_scan(local, sdata)) {
 673                 /* wait for the work to finish/time out */
 674                 rcu_assign_pointer(local->scan_req, req);
 675                 rcu_assign_pointer(local->scan_sdata, sdata);
 676                 return 0;
 677         }
 678
 679  again:
 680         if (hw_scan) {
 681                 u8 *ies;
 682
 683                 local->hw_scan_ies_bufsize = local->scan_ies_len + req->ie_len;
 684
 685                 if (ieee80211_hw_check(&local->hw, SINGLE_SCAN_ON_ALL_BANDS)) {
 686                         int i, n_bands = 0;
 687                         u8 bands_counted = 0;
 688
 689                         for (i = 0; i < req->n_channels; i++) {
 690                                 if (bands_counted & BIT(req->channels[i]->band))
 691                                         continue;
 692                                 bands_counted |= BIT(req->channels[i]->band);
 693                                 n_bands++;
 694                         }
 695
 696                         local->hw_scan_ies_bufsize *= n_bands;
 697                 }
 698
 699                 local->hw_scan_req = kmalloc(
 700                                 sizeof(*local->hw_scan_req) +
 701                                 req->n_channels * sizeof(req->channels[0]) +
 702                                 local->hw_scan_ies_bufsize, GFP_KERNEL);
 703                 if (!local->hw_scan_req)
 704                         return -ENOMEM;
 705
 706                 local->hw_scan_req->req.ssids = req->ssids;
 707                 local->hw_scan_req->req.n_ssids = req->n_ssids;
 708                 ies = (u8 *)local->hw_scan_req +
 709                         sizeof(*local->hw_scan_req) +
 710                         req->n_channels * sizeof(req->channels[0]);
 711                 local->hw_scan_req->req.ie = ies;
 712                 local->hw_scan_req->req.flags = req->flags;
 713                 eth_broadcast_addr(local->hw_scan_req->req.bssid);
 714                 local->hw_scan_req->req.duration = req->duration;
 715                 local->hw_scan_req->req.duration_mandatory =
 716                         req->duration_mandatory;
 717
 718                 local->hw_scan_band = 0;
 719
 720                 /*
 721                  * After allocating local->hw_scan_req, we must
 722                  * go through until ieee80211_prep_hw_scan(), so
 723                  * anything that might be changed here and leave
 724                  * this function early must not go after this
 725                  * allocation.
 726                  */
 727         }
 728
 729         rcu_assign_pointer(local->scan_req, req);
 730         rcu_assign_pointer(local->scan_sdata, sdata);
 731
 732         if (req->flags & NL80211_SCAN_FLAG_RANDOM_ADDR)
 733                 get_random_mask_addr(local->scan_addr,
 734                                      req->mac_addr,
 735                                      req->mac_addr_mask);
 736         else
 737                 memcpy(local->scan_addr, sdata->vif.addr, ETH_ALEN);
 738
 739         if (hw_scan) {
 740                 __set_bit(SCAN_HW_SCANNING, &local->scanning);
 741         } else if ((req->n_channels == 1) &&
 742                    (req->channels[0] == local->_oper_chandef.chan)) {
 743                 /*
 744                  * If we are scanning only on the operating channel
 745                  * then we do not need to stop normal activities
 746                  */
 747                 unsigned long next_delay;
 748
 749                 __set_bit(SCAN_ONCHANNEL_SCANNING, &local->scanning);
 750
 751                 ieee80211_recalc_idle(local);
 752
 753                 /* Notify driver scan is starting, keep order of operations
 754                  * same as normal software scan, in case that matters. */
 755                 drv_sw_scan_start(local, sdata, local->scan_addr);
 756
 757                 ieee80211_configure_filter(local); /* accept probe-responses */
 758
 759                 /* We need to ensure power level is at max for scanning. */
 760                 ieee80211_hw_config(local, 0);
 761
 762                 if ((req->channels[0]->flags & (IEEE80211_CHAN_NO_IR |
 763                                                 IEEE80211_CHAN_RADAR)) ||
 764                     !req->n_ssids) {
 765                         next_delay = IEEE80211_PASSIVE_CHANNEL_TIME;
 766                         if (req->n_ssids)
 767                                 set_bit(SCAN_BEACON_WAIT, &local->scanning);
 768                 } else {
 769                         ieee80211_scan_state_send_probe(local, &next_delay);
 770                         next_delay = IEEE80211_CHANNEL_TIME;
 771                 }
 772
 773                 /* Now, just wait a bit and we are all done! */
 774                 ieee80211_queue_delayed_work(&local->hw, &local->scan_work,
 775                                              next_delay);
 776                 return 0;
 777         } else {
 778                 /* Do normal software scan */
 779                 __set_bit(SCAN_SW_SCANNING, &local->scanning);
 780         }
 781
 782         ieee80211_recalc_idle(local);
 783
 784         if (hw_scan) {
 785                 WARN_ON(!ieee80211_prep_hw_scan(local));
 786                 rc = drv_hw_scan(local, sdata, local->hw_scan_req);
 787         } else {
 788                 rc = ieee80211_start_sw_scan(local, sdata);
 789         }
 790
 791         if (rc) {
 792                 kfree(local->hw_scan_req);
 793                 local->hw_scan_req = NULL;
 794                 local->scanning = 0;
 795
 796                 ieee80211_recalc_idle(local);
 797
 798                 local->scan_req = NULL;
 799                 RCU_INIT_POINTER(local->scan_sdata, NULL);
 800         }
 801
 802         if (hw_scan && rc == 1) {
 803                 /*
 804                  * we can't fall back to software for P2P-GO
 805                  * as it must update NoA etc.
 806                  */
 807                 if (ieee80211_vif_type_p2p(&sdata->vif) ==
 808                                 NL80211_IFTYPE_P2P_GO)
 809                         return -EOPNOTSUPP;
 810                 hw_scan = false;
 811                 goto again;
 812         }
 813
 814         return rc;
 815 }
 816
 817 static unsigned long
 818 ieee80211_scan_get_channel_time(struct ieee80211_channel *chan)
 819 {
 820         /*
 821          * TODO: channel switching also consumes quite some time,
 822          * add that delay as well to get a better estimation
 823          */
 824         if (chan->flags & (IEEE80211_CHAN_NO_IR | IEEE80211_CHAN_RADAR))
 825                 return IEEE80211_PASSIVE_CHANNEL_TIME;
 826         return IEEE80211_PROBE_DELAY + IEEE80211_CHANNEL_TIME;
 827 }
 828
 829 static void ieee80211_scan_state_decision(struct ieee80211_local *local,
 830                                           unsigned long *next_delay)
 831 {
 832         bool associated = false;
 833         bool tx_empty = true;
 834         bool bad_latency;
 835         struct ieee80211_sub_if_data *sdata;
 836         struct ieee80211_channel *next_chan;
 837         enum mac80211_scan_state next_scan_state;
 838         struct cfg80211_scan_request *scan_req;
 839
 840         /*
 841          * check if at least one STA interface is associated,
 842          * check if at least one STA interface has pending tx frames
 843          * and grab the lowest used beacon interval
 844          */
 845         mutex_lock(&local->iflist_mtx);
 846         list_for_each_entry(sdata, &local->interfaces, list) {
 847                 if (!ieee80211_sdata_running(sdata))
 848                         continue;
 849
 850                 if (sdata->vif.type == NL80211_IFTYPE_STATION) {
 851                         if (sdata->u.mgd.associated) {
 852                                 associated = true;
 853
 854                                 if (!qdisc_all_tx_empty(sdata->dev)) {
 855                                         tx_empty = false;
 856                                         break;
 857                                 }
 858                         }
 859                 }
 860         }
 861         mutex_unlock(&local->iflist_mtx);
 862
 863         scan_req = rcu_dereference_protected(local->scan_req,
 864                                              lockdep_is_held(&local->mtx));
 865
 866         next_chan = scan_req->channels[local->scan_channel_idx];
 867
 868         /*
 869          * we're currently scanning a different channel, let's
 870          * see if we can scan another channel without interfering
 871          * with the current traffic situation.
 872          *
 873          * Keep good latency, do not stay off-channel more than 125 ms.
 874          */
 875
 876         bad_latency = time_after(jiffies +
 877                                  ieee80211_scan_get_channel_time(next_chan),
 878                                  local->leave_oper_channel_time + HZ / 8);
 879
 880         if (associated && !tx_empty) {
 881                 if (scan_req->flags & NL80211_SCAN_FLAG_LOW_PRIORITY)
 882                         next_scan_state = SCAN_ABORT;
 883                 else
 884                         next_scan_state = SCAN_SUSPEND;
 885         } else if (associated && bad_latency) {
 886                 next_scan_state = SCAN_SUSPEND;
 887         } else {
 888                 next_scan_state = SCAN_SET_CHANNEL;
 889         }
 890
 891         local->next_scan_state = next_scan_state;
 892
 893         *next_delay = 0;
 894 }
 895
 896 static void ieee80211_scan_state_set_channel(struct ieee80211_local *local,
 897                                              unsigned long *next_delay)
 898 {
 899         int skip;
 900         struct ieee80211_channel *chan;
 901         enum nl80211_bss_scan_width oper_scan_width;
 902         struct cfg80211_scan_request *scan_req;
 903
 904         scan_req = rcu_dereference_protected(local->scan_req,
 905                                              lockdep_is_held(&local->mtx));
 906
 907         skip = 0;
 908         chan = scan_req->channels[local->scan_channel_idx];
 909
 910         local->scan_chandef.chan = chan;
 911         local->scan_chandef.center_freq1 = chan->center_freq;
 912         local->scan_chandef.center_freq2 = 0;
 913         switch (scan_req->scan_width) {
 914         case NL80211_BSS_CHAN_WIDTH_5:
 915                 local->scan_chandef.width = NL80211_CHAN_WIDTH_5;
 916                 break;
 917         case NL80211_BSS_CHAN_WIDTH_10:
 918                 local->scan_chandef.width = NL80211_CHAN_WIDTH_10;
 919                 break;
 920         case NL80211_BSS_CHAN_WIDTH_20:
 921                 /* If scanning on oper channel, use whatever channel-type
 922                  * is currently in use.
 923                  */
 924                 oper_scan_width = cfg80211_chandef_to_scan_width(
 925                                         &local->_oper_chandef);
 926                 if (chan == local->_oper_chandef.chan &&
 927                     oper_scan_width == scan_req->scan_width)
 928                         local->scan_chandef = local->_oper_chandef;
 929                 else
 930                         local->scan_chandef.width = NL80211_CHAN_WIDTH_20_NOHT;
 931                 break;
 932         }
 933
 934         if (ieee80211_hw_config(local, IEEE80211_CONF_CHANGE_CHANNEL))
 935                 skip = 1;
 936
 937         /* advance state machine to next channel/band */
 938         local->scan_channel_idx++;
 939
 940         if (skip) {
 941                 /* if we skip this channel return to the decision state */
 942                 local->next_scan_state = SCAN_DECISION;
 943                 return;
 944         }
 945
 946         /*
 947          * Probe delay is used to update the NAV, cf. 11.1.3.2.2
 948          * (which unfortunately doesn't say _why_ step a) is done,
 949          * but it waits for the probe delay or until a frame is
 950          * received - and the received frame would update the NAV).
 951          * For now, we do not support waiting until a frame is
 952          * received.
 953          *
 954          * In any case, it is not necessary for a passive scan.
 955          */
 956         if ((chan->flags & (IEEE80211_CHAN_NO_IR | IEEE80211_CHAN_RADAR)) ||
 957             !scan_req->n_ssids) {
 958                 *next_delay = IEEE80211_PASSIVE_CHANNEL_TIME;
 959                 local->next_scan_state = SCAN_DECISION;
 960                 if (scan_req->n_ssids)
 961                         set_bit(SCAN_BEACON_WAIT, &local->scanning);
 962                 return;
 963         }
 964
 965         /* active scan, send probes */
 966         *next_delay = IEEE80211_PROBE_DELAY;
 967         local->next_scan_state = SCAN_SEND_PROBE;
 968 }
 969
 970 static void ieee80211_scan_state_suspend(struct ieee80211_local *local,
 971                                          unsigned long *next_delay)
 972 {
 973         /* switch back to the operating channel */
 974         local->scan_chandef.chan = NULL;
 975         ieee80211_hw_config(local, IEEE80211_CONF_CHANGE_CHANNEL);
 976
 977         /* disable PS */
 978         ieee80211_offchannel_return(local);
 979
 980         *next_delay = HZ / 5;
 981         /* afterwards, resume scan & go to next channel */
 982         local->next_scan_state = SCAN_RESUME;
 983 }
 984
 985 static void ieee80211_scan_state_resume(struct ieee80211_local *local,
 986                                         unsigned long *next_delay)
 987 {
 988         ieee80211_offchannel_stop_vifs(local);
 989
 990         if (local->ops->flush) {
 991                 ieee80211_flush_queues(local, NULL, false);
 992                 *next_delay = 0;
 993         } else
 994                 *next_delay = HZ / 10;
 995
 996         /* remember when we left the operating channel */
 997         local->leave_oper_channel_time = jiffies;
 998
 999         /* advance to the next channel to be scanned */
1000         local->next_scan_state = SCAN_SET_CHANNEL;
1001 }
1002
1003 void ieee80211_scan_work(struct work_struct *work)
1004 {
1005         struct ieee80211_local *local =
1006                 container_of(work, struct ieee80211_local, scan_work.work);
1007         struct ieee80211_sub_if_data *sdata;
1008         struct cfg80211_scan_request *scan_req;
1009         unsigned long next_delay = 0;
1010         bool aborted;
1011
1012         mutex_lock(&local->mtx);
1013
1014         if (!ieee80211_can_run_worker(local)) {
1015                 aborted = true;
1016                 goto out_complete;
1017         }
1018
1019         sdata = rcu_dereference_protected(local->scan_sdata,
1020                                           lockdep_is_held(&local->mtx));
1021         scan_req = rcu_dereference_protected(local->scan_req,
1022                                              lockdep_is_held(&local->mtx));
1023
1024         /* When scanning on-channel, the first-callback means completed. */
1025         if (test_bit(SCAN_ONCHANNEL_SCANNING, &local->scanning)) {
1026                 aborted = test_and_clear_bit(SCAN_ABORTED, &local->scanning);
1027                 goto out_complete;
1028         }
1029
1030         if (test_and_clear_bit(SCAN_COMPLETED, &local->scanning)) {
1031                 aborted = test_and_clear_bit(SCAN_ABORTED, &local->scanning);
1032                 goto out_complete;
1033         }
1034
1035         if (!sdata || !scan_req)
1036                 goto out;
1037
1038         if (!local->scanning) {
1039                 int rc;
1040
1041                 RCU_INIT_POINTER(local->scan_req, NULL);
1042                 RCU_INIT_POINTER(local->scan_sdata, NULL);
1043
1044                 rc = __ieee80211_start_scan(sdata, scan_req);
1045                 if (rc) {
1046                         /* need to complete scan in cfg80211 */
1047                         rcu_assign_pointer(local->scan_req, scan_req);
1048                         aborted = true;
1049                         goto out_complete;
1050                 } else
1051                         goto out;
1052         }
1053
1054         clear_bit(SCAN_BEACON_WAIT, &local->scanning);
1055
1056         /*
1057          * as long as no delay is required advance immediately
1058          * without scheduling a new work
1059          */
1060         do {
1061                 if (!ieee80211_sdata_running(sdata)) {
1062                         aborted = true;
1063                         goto out_complete;
1064                 }
1065
1066                 if (test_and_clear_bit(SCAN_BEACON_DONE, &local->scanning) &&
1067                     local->next_scan_state == SCAN_DECISION)
1068                         local->next_scan_state = SCAN_SEND_PROBE;
1069
1070                 switch (local->next_scan_state) {
1071                 case SCAN_DECISION:
1072                         /* if no more bands/channels left, complete scan */
1073                         if (local->scan_channel_idx >= scan_req->n_channels) {
1074                                 aborted = false;
1075                                 goto out_complete;
1076                         }
1077                         ieee80211_scan_state_decision(local, &next_delay);
1078                         break;
1079                 case SCAN_SET_CHANNEL:
1080                         ieee80211_scan_state_set_channel(local, &next_delay);
1081                         break;
1082                 case SCAN_SEND_PROBE:
1083                         ieee80211_scan_state_send_probe(local, &next_delay);
1084                         break;
1085                 case SCAN_SUSPEND:
1086                         ieee80211_scan_state_suspend(local, &next_delay);
1087                         break;
1088                 case SCAN_RESUME:
1089                         ieee80211_scan_state_resume(local, &next_delay);
1090                         break;
1091                 case SCAN_ABORT:
1092                         aborted = true;
1093                         goto out_complete;
1094                 }
1095         } while (next_delay == 0);
1096
1097         ieee80211_queue_delayed_work(&local->hw, &local->scan_work, next_delay);
1098         goto out;
1099
1100 out_complete:
1101         __ieee80211_scan_completed(&local->hw, aborted);
1102 out:
1103         mutex_unlock(&local->mtx);
1104 }
1105
1106 int ieee80211_request_scan(struct ieee80211_sub_if_data *sdata,
1107                            struct cfg80211_scan_request *req)
1108 {
1109         int res;
1110
1111         mutex_lock(&sdata->local->mtx);
1112         res = __ieee80211_start_scan(sdata, req);
1113         mutex_unlock(&sdata->local->mtx);
1114
1115         return res;
1116 }
1117
1118 int ieee80211_request_ibss_scan(struct ieee80211_sub_if_data *sdata,
1119                                 const u8 *ssid, u8 ssid_len,
1120                                 struct ieee80211_channel **channels,
1121                                 unsigned int n_channels,
1122                                 enum nl80211_bss_scan_width scan_width)
1123 {
1124         struct ieee80211_local *local = sdata->local;
1125         int ret = -EBUSY, i, n_ch = 0;
1126         enum nl80211_band band;
1127
1128         mutex_lock(&local->mtx);
1129
1130         /* busy scanning */
1131         if (local->scan_req)
1132                 goto unlock;
1133
1134         /* fill internal scan request */
1135         if (!channels) {
1136                 int max_n;
1137
1138                 for (band = 0; band < NUM_NL80211_BANDS; band++) {
1139                         if (!local->hw.wiphy->bands[band])
1140                                 continue;
1141
1142                         max_n = local->hw.wiphy->bands[band]->n_channels;
1143                         for (i = 0; i < max_n; i++) {
1144                                 struct ieee80211_channel *tmp_ch =
1145                                     &local->hw.wiphy->bands[band]->channels[i];
1146
1147                                 if (tmp_ch->flags & (IEEE80211_CHAN_NO_IR |
1148                                                      IEEE80211_CHAN_DISABLED))
1149                                         continue;
1150
1151                                 local->int_scan_req->channels[n_ch] = tmp_ch;
1152                                 n_ch++;
1153                         }
1154                 }
1155
1156                 if (WARN_ON_ONCE(n_ch == 0))
1157                         goto unlock;
1158
1159                 local->int_scan_req->n_channels = n_ch;
1160         } else {
1161                 for (i = 0; i < n_channels; i++) {
1162                         if (channels[i]->flags & (IEEE80211_CHAN_NO_IR |
1163                                                   IEEE80211_CHAN_DISABLED))
1164                                 continue;
1165
1166                         local->int_scan_req->channels[n_ch] = channels[i];
1167                         n_ch++;
1168                 }
1169
1170                 if (WARN_ON_ONCE(n_ch == 0))
1171                         goto unlock;
1172
1173                 local->int_scan_req->n_channels = n_ch;
1174         }
1175
1176         local->int_scan_req->ssids = &local->scan_ssid;
1177         local->int_scan_req->n_ssids = 1;
1178         local->int_scan_req->scan_width = scan_width;
1179         memcpy(local->int_scan_req->ssids[0].ssid, ssid, IEEE80211_MAX_SSID_LEN);
1180         local->int_scan_req->ssids[0].ssid_len = ssid_len;
1181
1182         ret = __ieee80211_start_scan(sdata, sdata->local->int_scan_req);
1183  unlock:
1184         mutex_unlock(&local->mtx);
1185         return ret;
1186 }
1187
1188 /*
1189  * Only call this function when a scan can't be queued -- under RTNL.
1190  */
1191 void ieee80211_scan_cancel(struct ieee80211_local *local)
1192 {
1193         /*
1194          * We are canceling software scan, or deferred scan that was not
1195          * yet really started (see __ieee80211_start_scan ).
1196          *
1197          * Regarding hardware scan:
1198          * - we can not call  __ieee80211_scan_completed() as when
1199          *   SCAN_HW_SCANNING bit is set this function change
1200          *   local->hw_scan_req to operate on 5G band, what race with
1201          *   driver which can use local->hw_scan_req
1202          *
1203          * - we can not cancel scan_work since driver can schedule it
1204          *   by ieee80211_scan_completed(..., true) to finish scan
1205          *
1206          * Hence we only call the cancel_hw_scan() callback, but the low-level
1207          * driver is still responsible for calling ieee80211_scan_completed()
1208          * after the scan was completed/aborted.
1209          */
1210
1211         mutex_lock(&local->mtx);
1212         if (!local->scan_req)
1213                 goto out;
1214
1215         /*
1216          * We have a scan running and the driver already reported completion,
1217          * but the worker hasn't run yet or is stuck on the mutex - mark it as
1218          * cancelled.
1219          */
1220         if (test_bit(SCAN_HW_SCANNING, &local->scanning) &&
1221             test_bit(SCAN_COMPLETED, &local->scanning)) {
1222                 set_bit(SCAN_HW_CANCELLED, &local->scanning);
1223                 goto out;
1224         }
1225
1226         if (test_bit(SCAN_HW_SCANNING, &local->scanning)) {
1227                 /*
1228                  * Make sure that __ieee80211_scan_completed doesn't trigger a
1229                  * scan on another band.
1230                  */
1231                 set_bit(SCAN_HW_CANCELLED, &local->scanning);
1232                 if (local->ops->cancel_hw_scan)
1233                         drv_cancel_hw_scan(local,
1234                                 rcu_dereference_protected(local->scan_sdata,
1235                                                 lockdep_is_held(&local->mtx)));
1236                 goto out;
1237         }
1238
1239         /*
1240          * If the work is currently running, it must be blocked on
1241          * the mutex, but we'll set scan_sdata = NULL and it'll
1242          * simply exit once it acquires the mutex.
1243          */
1244         cancel_delayed_work(&local->scan_work);
1245         /* and clean up */
1246         memset(&local->scan_info, 0, sizeof(local->scan_info));
1247         __ieee80211_scan_completed(&local->hw, true);
1248 out:
1249         mutex_unlock(&local->mtx);
1250 }
1251
1252 int __ieee80211_request_sched_scan_start(struct ieee80211_sub_if_data *sdata,
1253                                         struct cfg80211_sched_scan_request *req)
1254 {
1255         struct ieee80211_local *local = sdata->local;
1256         struct ieee80211_scan_ies sched_scan_ies = {};
1257         struct cfg80211_chan_def chandef;
1258         int ret, i, iebufsz, num_bands = 0;
1259         u32 rate_masks[NUM_NL80211_BANDS] = {};
1260         u8 bands_used = 0;
1261         u8 *ie;
1262         u32 flags = 0;
1263
1264         iebufsz = local->scan_ies_len + req->ie_len;
1265
1266         lockdep_assert_held(&local->mtx);
1267
1268         if (!local->ops->sched_scan_start)
1269                 return -ENOTSUPP;
1270
1271         for (i = 0; i < NUM_NL80211_BANDS; i++) {
1272                 if (local->hw.wiphy->bands[i]) {
1273                         bands_used |= BIT(i);
1274                         rate_masks[i] = (u32) -1;
1275                         num_bands++;
1276                 }
1277         }
1278
1279         if (req->flags & NL80211_SCAN_FLAG_MIN_PREQ_CONTENT)
1280                 flags |= IEEE80211_PROBE_FLAG_MIN_CONTENT;
1281
1282         ie = kcalloc(iebufsz, num_bands, GFP_KERNEL);
1283         if (!ie) {
1284                 ret = -ENOMEM;
1285                 goto out;
1286         }
1287
1288         ieee80211_prepare_scan_chandef(&chandef, req->scan_width);
1289
1290         ieee80211_build_preq_ies(local, ie, num_bands * iebufsz,
1291                                  &sched_scan_ies, req->ie,
1292                                  req->ie_len, bands_used, rate_masks, &chandef,
1293                                  flags);
1294
1295         ret = drv_sched_scan_start(local, sdata, req, &sched_scan_ies);
1296         if (ret == 0) {
1297                 rcu_assign_pointer(local->sched_scan_sdata, sdata);
1298                 rcu_assign_pointer(local->sched_scan_req, req);
1299         }
1300
1301         kfree(ie);
1302
1303 out:
1304         if (ret) {
1305                 /* Clean in case of failure after HW restart or upon resume. */
1306                 RCU_INIT_POINTER(local->sched_scan_sdata, NULL);
1307                 RCU_INIT_POINTER(local->sched_scan_req, NULL);
1308         }
1309
1310         return ret;
1311 }
1312
1313 int ieee80211_request_sched_scan_start(struct ieee80211_sub_if_data *sdata,
1314                                        struct cfg80211_sched_scan_request *req)
1315 {
1316         struct ieee80211_local *local = sdata->local;
1317         int ret;
1318
1319         mutex_lock(&local->mtx);
1320
1321         if (rcu_access_pointer(local->sched_scan_sdata)) {
1322                 mutex_unlock(&local->mtx);
1323                 return -EBUSY;
1324         }
1325
1326         ret = __ieee80211_request_sched_scan_start(sdata, req);
1327
1328         mutex_unlock(&local->mtx);
1329         return ret;
1330 }
1331
1332 int ieee80211_request_sched_scan_stop(struct ieee80211_local *local)
1333 {
1334         struct ieee80211_sub_if_data *sched_scan_sdata;
1335         int ret = -ENOENT;
1336
1337         mutex_lock(&local->mtx);
1338
1339         if (!local->ops->sched_scan_stop) {
1340                 ret = -ENOTSUPP;
1341                 goto out;
1342         }
1343
1344         /* We don't want to restart sched scan anymore. */
1345         RCU_INIT_POINTER(local->sched_scan_req, NULL);
1346
1347         sched_scan_sdata = rcu_dereference_protected(local->sched_scan_sdata,
1348                                                 lockdep_is_held(&local->mtx));
1349         if (sched_scan_sdata) {
1350                 ret = drv_sched_scan_stop(local, sched_scan_sdata);
1351                 if (!ret)
1352                         RCU_INIT_POINTER(local->sched_scan_sdata, NULL);
1353         }
1354 out:
1355         mutex_unlock(&local->mtx);
1356
1357         return ret;
1358 }
1359
1360 void ieee80211_sched_scan_results(struct ieee80211_hw *hw)
1361 {
1362         struct ieee80211_local *local = hw_to_local(hw);
1363
1364         trace_api_sched_scan_results(local);
1365
1366         cfg80211_sched_scan_results(hw->wiphy, 0);
1367 }
1368 EXPORT_SYMBOL(ieee80211_sched_scan_results);
1369
1370 void ieee80211_sched_scan_end(struct ieee80211_local *local)
1371 {
1372         mutex_lock(&local->mtx);
1373
1374         if (!rcu_access_pointer(local->sched_scan_sdata)) {
1375                 mutex_unlock(&local->mtx);
1376                 return;
1377         }
1378
1379         RCU_INIT_POINTER(local->sched_scan_sdata, NULL);
1380
1381         /* If sched scan was aborted by the driver. */
1382         RCU_INIT_POINTER(local->sched_scan_req, NULL);
1383
1384         mutex_unlock(&local->mtx);
1385
1386         cfg80211_sched_scan_stopped(local->hw.wiphy, 0);
1387 }
1388
1389 void ieee80211_sched_scan_stopped_work(struct work_struct *work)
1390 {
1391         struct ieee80211_local *local =
1392                 container_of(work, struct ieee80211_local,
1393                              sched_scan_stopped_work);
1394
1395         ieee80211_sched_scan_end(local);
1396 }
1397
1398 void ieee80211_sched_scan_stopped(struct ieee80211_hw *hw)
1399 {
1400         struct ieee80211_local *local = hw_to_local(hw);
1401
1402         trace_api_sched_scan_stopped(local);
1403
1404         /*
1405          * this shouldn't really happen, so for simplicity
1406          * simply ignore it, and let mac80211 reconfigure
1407          * the sched scan later on.
1408          */
1409         if (local->in_reconfig)
1410                 return;
1411
1412         schedule_work(&local->sched_scan_stopped_work);
1413 }
1414 EXPORT_SYMBOL(ieee80211_sched_scan_stopped);