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) 2018-2023 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 struct inform_bss_update_data {
  59         struct ieee80211_rx_status *rx_status;
  60         bool beacon;
  61 };
  62
  63 void ieee80211_inform_bss(struct wiphy *wiphy,
  64                           struct cfg80211_bss *cbss,
  65                           const struct cfg80211_bss_ies *ies,
  66                           void *data)
  67 {
  68         struct ieee80211_local *local = wiphy_priv(wiphy);
  69         struct inform_bss_update_data *update_data = data;
  70         struct ieee80211_bss *bss = (void *)cbss->priv;
  71         struct ieee80211_rx_status *rx_status;
  72         struct ieee802_11_elems *elems;
  73         int clen, srlen;
  74
  75         /* This happens while joining an IBSS */
  76         if (!update_data)
  77                 return;
  78
  79         elems = ieee802_11_parse_elems(ies->data, ies->len, false, NULL);
  80         if (!elems)
  81                 return;
  82
  83         rx_status = update_data->rx_status;
  84
  85         if (update_data->beacon)
  86                 bss->device_ts_beacon = rx_status->device_timestamp;
  87         else
  88                 bss->device_ts_presp = rx_status->device_timestamp;
  89
  90         if (elems->parse_error) {
  91                 if (update_data->beacon)
  92                         bss->corrupt_data |= IEEE80211_BSS_CORRUPT_BEACON;
  93                 else
  94                         bss->corrupt_data |= IEEE80211_BSS_CORRUPT_PROBE_RESP;
  95         } else {
  96                 if (update_data->beacon)
  97                         bss->corrupt_data &= ~IEEE80211_BSS_CORRUPT_BEACON;
  98                 else
  99                         bss->corrupt_data &= ~IEEE80211_BSS_CORRUPT_PROBE_RESP;
 100         }
 101
 102         /* save the ERP value so that it is available at association time */
 103         if (elems->erp_info && (!elems->parse_error ||
 104                                 !(bss->valid_data & IEEE80211_BSS_VALID_ERP))) {
 105                 bss->erp_value = elems->erp_info[0];
 106                 bss->has_erp_value = true;
 107                 if (!elems->parse_error)
 108                         bss->valid_data |= IEEE80211_BSS_VALID_ERP;
 109         }
 110
 111         /* replace old supported rates if we get new values */
 112         if (!elems->parse_error ||
 113             !(bss->valid_data & IEEE80211_BSS_VALID_RATES)) {
 114                 srlen = 0;
 115                 if (elems->supp_rates) {
 116                         clen = IEEE80211_MAX_SUPP_RATES;
 117                         if (clen > elems->supp_rates_len)
 118                                 clen = elems->supp_rates_len;
 119                         memcpy(bss->supp_rates, elems->supp_rates, clen);
 120                         srlen += clen;
 121                 }
 122                 if (elems->ext_supp_rates) {
 123                         clen = IEEE80211_MAX_SUPP_RATES - srlen;
 124                         if (clen > elems->ext_supp_rates_len)
 125                                 clen = elems->ext_supp_rates_len;
 126                         memcpy(bss->supp_rates + srlen, elems->ext_supp_rates,
 127                                clen);
 128                         srlen += clen;
 129                 }
 130                 if (srlen) {
 131                         bss->supp_rates_len = srlen;
 132                         if (!elems->parse_error)
 133                                 bss->valid_data |= IEEE80211_BSS_VALID_RATES;
 134                 }
 135         }
 136
 137         if (!elems->parse_error ||
 138             !(bss->valid_data & IEEE80211_BSS_VALID_WMM)) {
 139                 bss->wmm_used = elems->wmm_param || elems->wmm_info;
 140                 bss->uapsd_supported = is_uapsd_supported(elems);
 141                 if (!elems->parse_error)
 142                         bss->valid_data |= IEEE80211_BSS_VALID_WMM;
 143         }
 144
 145         if (update_data->beacon) {
 146                 struct ieee80211_supported_band *sband =
 147                         local->hw.wiphy->bands[rx_status->band];
 148                 if (!(rx_status->encoding == RX_ENC_HT) &&
 149                     !(rx_status->encoding == RX_ENC_VHT))
 150                         bss->beacon_rate =
 151                                 &sband->bitrates[rx_status->rate_idx];
 152         }
 153
 154         if (elems->vht_cap_elem)
 155                 bss->vht_cap_info =
 156                         le32_to_cpu(elems->vht_cap_elem->vht_cap_info);
 157         else
 158                 bss->vht_cap_info = 0;
 159
 160         kfree(elems);
 161 }
 162
 163 struct ieee80211_bss *
 164 ieee80211_bss_info_update(struct ieee80211_local *local,
 165                           struct ieee80211_rx_status *rx_status,
 166                           struct ieee80211_mgmt *mgmt, size_t len,
 167                           struct ieee80211_channel *channel)
 168 {
 169         bool beacon = ieee80211_is_beacon(mgmt->frame_control) ||
 170                       ieee80211_is_s1g_beacon(mgmt->frame_control);
 171         struct cfg80211_bss *cbss;
 172         struct inform_bss_update_data update_data = {
 173                 .rx_status = rx_status,
 174                 .beacon = beacon,
 175         };
 176         struct cfg80211_inform_bss bss_meta = {
 177                 .boottime_ns = rx_status->boottime_ns,
 178                 .drv_data = (void *)&update_data,
 179         };
 180         bool signal_valid;
 181         struct ieee80211_sub_if_data *scan_sdata;
 182
 183         if (rx_status->flag & RX_FLAG_NO_SIGNAL_VAL)
 184                 bss_meta.signal = 0; /* invalid signal indication */
 185         else if (ieee80211_hw_check(&local->hw, SIGNAL_DBM))
 186                 bss_meta.signal = rx_status->signal * 100;
 187         else if (ieee80211_hw_check(&local->hw, SIGNAL_UNSPEC))
 188                 bss_meta.signal = (rx_status->signal * 100) / local->hw.max_signal;
 189
 190         bss_meta.scan_width = NL80211_BSS_CHAN_WIDTH_20;
 191         if (rx_status->bw == RATE_INFO_BW_5)
 192                 bss_meta.scan_width = NL80211_BSS_CHAN_WIDTH_5;
 193         else if (rx_status->bw == RATE_INFO_BW_10)
 194                 bss_meta.scan_width = NL80211_BSS_CHAN_WIDTH_10;
 195
 196         bss_meta.chan = channel;
 197
 198         rcu_read_lock();
 199         scan_sdata = rcu_dereference(local->scan_sdata);
 200         if (scan_sdata && scan_sdata->vif.type == NL80211_IFTYPE_STATION &&
 201             scan_sdata->vif.cfg.assoc &&
 202             ieee80211_have_rx_timestamp(rx_status)) {
 203                 bss_meta.parent_tsf =
 204                         ieee80211_calculate_rx_timestamp(local, rx_status,
 205                                                          len + FCS_LEN, 24);
 206                 ether_addr_copy(bss_meta.parent_bssid,
 207                                 scan_sdata->vif.bss_conf.bssid);
 208         }
 209         rcu_read_unlock();
 210
 211         cbss = cfg80211_inform_bss_frame_data(local->hw.wiphy, &bss_meta,
 212                                               mgmt, len, GFP_ATOMIC);
 213         if (!cbss)
 214                 return NULL;
 215
 216         /* In case the signal is invalid update the status */
 217         signal_valid = channel == cbss->channel;
 218         if (!signal_valid)
 219                 rx_status->flag |= RX_FLAG_NO_SIGNAL_VAL;
 220
 221         return (void *)cbss->priv;
 222 }
 223
 224 static bool ieee80211_scan_accept_presp(struct ieee80211_sub_if_data *sdata,
 225                                         u32 scan_flags, const u8 *da)
 226 {
 227         if (!sdata)
 228                 return false;
 229         /* accept broadcast for OCE */
 230         if (scan_flags & NL80211_SCAN_FLAG_ACCEPT_BCAST_PROBE_RESP &&
 231             is_broadcast_ether_addr(da))
 232                 return true;
 233         if (scan_flags & NL80211_SCAN_FLAG_RANDOM_ADDR)
 234                 return true;
 235         return ether_addr_equal(da, sdata->vif.addr);
 236 }
 237
 238 void ieee80211_scan_rx(struct ieee80211_local *local, struct sk_buff *skb)
 239 {
 240         struct ieee80211_rx_status *rx_status = IEEE80211_SKB_RXCB(skb);
 241         struct ieee80211_sub_if_data *sdata1, *sdata2;
 242         struct ieee80211_mgmt *mgmt = (void *)skb->data;
 243         struct ieee80211_bss *bss;
 244         struct ieee80211_channel *channel;
 245         size_t min_hdr_len = offsetof(struct ieee80211_mgmt,
 246                                       u.probe_resp.variable);
 247
 248         if (!ieee80211_is_probe_resp(mgmt->frame_control) &&
 249             !ieee80211_is_beacon(mgmt->frame_control) &&
 250             !ieee80211_is_s1g_beacon(mgmt->frame_control))
 251                 return;
 252
 253         if (ieee80211_is_s1g_beacon(mgmt->frame_control)) {
 254                 if (ieee80211_is_s1g_short_beacon(mgmt->frame_control))
 255                         min_hdr_len = offsetof(struct ieee80211_ext,
 256                                                u.s1g_short_beacon.variable);
 257                 else
 258                         min_hdr_len = offsetof(struct ieee80211_ext,
 259                                                u.s1g_beacon);
 260         }
 261
 262         if (skb->len < min_hdr_len)
 263                 return;
 264
 265         sdata1 = rcu_dereference(local->scan_sdata);
 266         sdata2 = rcu_dereference(local->sched_scan_sdata);
 267
 268         if (likely(!sdata1 && !sdata2))
 269                 return;
 270
 271         if (test_and_clear_bit(SCAN_BEACON_WAIT, &local->scanning)) {
 272                 /*
 273                  * we were passive scanning because of radar/no-IR, but
 274                  * the beacon/proberesp rx gives us an opportunity to upgrade
 275                  * to active scan
 276                  */
 277                 set_bit(SCAN_BEACON_DONE, &local->scanning);
 278                 wiphy_delayed_work_queue(local->hw.wiphy, &local->scan_work, 0);
 279         }
 280
 281         if (ieee80211_is_probe_resp(mgmt->frame_control)) {
 282                 struct cfg80211_scan_request *scan_req;
 283                 struct cfg80211_sched_scan_request *sched_scan_req;
 284                 u32 scan_req_flags = 0, sched_scan_req_flags = 0;
 285
 286                 scan_req = rcu_dereference(local->scan_req);
 287                 sched_scan_req = rcu_dereference(local->sched_scan_req);
 288
 289                 if (scan_req)
 290                         scan_req_flags = scan_req->flags;
 291
 292                 if (sched_scan_req)
 293                         sched_scan_req_flags = sched_scan_req->flags;
 294
 295                 /* ignore ProbeResp to foreign address or non-bcast (OCE)
 296                  * unless scanning with randomised address
 297                  */
 298                 if (!ieee80211_scan_accept_presp(sdata1, scan_req_flags,
 299                                                  mgmt->da) &&
 300                     !ieee80211_scan_accept_presp(sdata2, sched_scan_req_flags,
 301                                                  mgmt->da))
 302                         return;
 303         }
 304
 305         channel = ieee80211_get_channel_khz(local->hw.wiphy,
 306                                         ieee80211_rx_status_to_khz(rx_status));
 307
 308         if (!channel || channel->flags & IEEE80211_CHAN_DISABLED)
 309                 return;
 310
 311         bss = ieee80211_bss_info_update(local, rx_status,
 312                                         mgmt, skb->len,
 313                                         channel);
 314         if (bss)
 315                 ieee80211_rx_bss_put(local, bss);
 316 }
 317
 318 static void
 319 ieee80211_prepare_scan_chandef(struct cfg80211_chan_def *chandef,
 320                                enum nl80211_bss_scan_width scan_width)
 321 {
 322         memset(chandef, 0, sizeof(*chandef));
 323         switch (scan_width) {
 324         case NL80211_BSS_CHAN_WIDTH_5:
 325                 chandef->width = NL80211_CHAN_WIDTH_5;
 326                 break;
 327         case NL80211_BSS_CHAN_WIDTH_10:
 328                 chandef->width = NL80211_CHAN_WIDTH_10;
 329                 break;
 330         default:
 331                 chandef->width = NL80211_CHAN_WIDTH_20_NOHT;
 332                 break;
 333         }
 334 }
 335
 336 /* return false if no more work */
 337 static bool ieee80211_prep_hw_scan(struct ieee80211_sub_if_data *sdata)
 338 {
 339         struct ieee80211_local *local = sdata->local;
 340         struct cfg80211_scan_request *req;
 341         struct cfg80211_chan_def chandef;
 342         u8 bands_used = 0;
 343         int i, ielen, n_chans;
 344         u32 flags = 0;
 345
 346         req = rcu_dereference_protected(local->scan_req,
 347                                         lockdep_is_held(&local->mtx));
 348
 349         if (test_bit(SCAN_HW_CANCELLED, &local->scanning))
 350                 return false;
 351
 352         if (ieee80211_hw_check(&local->hw, SINGLE_SCAN_ON_ALL_BANDS)) {
 353                 for (i = 0; i < req->n_channels; i++) {
 354                         local->hw_scan_req->req.channels[i] = req->channels[i];
 355                         bands_used |= BIT(req->channels[i]->band);
 356                 }
 357
 358                 n_chans = req->n_channels;
 359         } else {
 360                 do {
 361                         if (local->hw_scan_band == NUM_NL80211_BANDS)
 362                                 return false;
 363
 364                         n_chans = 0;
 365
 366                         for (i = 0; i < req->n_channels; i++) {
 367                                 if (req->channels[i]->band !=
 368                                     local->hw_scan_band)
 369                                         continue;
 370                                 local->hw_scan_req->req.channels[n_chans] =
 371                                                         req->channels[i];
 372                                 n_chans++;
 373                                 bands_used |= BIT(req->channels[i]->band);
 374                         }
 375
 376                         local->hw_scan_band++;
 377                 } while (!n_chans);
 378         }
 379
 380         local->hw_scan_req->req.n_channels = n_chans;
 381         ieee80211_prepare_scan_chandef(&chandef, req->scan_width);
 382
 383         if (req->flags & NL80211_SCAN_FLAG_MIN_PREQ_CONTENT)
 384                 flags |= IEEE80211_PROBE_FLAG_MIN_CONTENT;
 385
 386         ielen = ieee80211_build_preq_ies(sdata,
 387                                          (u8 *)local->hw_scan_req->req.ie,
 388                                          local->hw_scan_ies_bufsize,
 389                                          &local->hw_scan_req->ies,
 390                                          req->ie, req->ie_len,
 391                                          bands_used, req->rates, &chandef,
 392                                          flags);
 393         local->hw_scan_req->req.ie_len = ielen;
 394         local->hw_scan_req->req.no_cck = req->no_cck;
 395         ether_addr_copy(local->hw_scan_req->req.mac_addr, req->mac_addr);
 396         ether_addr_copy(local->hw_scan_req->req.mac_addr_mask,
 397                         req->mac_addr_mask);
 398         ether_addr_copy(local->hw_scan_req->req.bssid, req->bssid);
 399
 400         return true;
 401 }
 402
 403 static void __ieee80211_scan_completed(struct ieee80211_hw *hw, bool aborted)
 404 {
 405         struct ieee80211_local *local = hw_to_local(hw);
 406         bool hw_scan = test_bit(SCAN_HW_SCANNING, &local->scanning);
 407         bool was_scanning = local->scanning;
 408         struct cfg80211_scan_request *scan_req;
 409         struct ieee80211_sub_if_data *scan_sdata;
 410         struct ieee80211_sub_if_data *sdata;
 411
 412         lockdep_assert_held(&local->mtx);
 413
 414         /*
 415          * It's ok to abort a not-yet-running scan (that
 416          * we have one at all will be verified by checking
 417          * local->scan_req next), but not to complete it
 418          * successfully.
 419          */
 420         if (WARN_ON(!local->scanning && !aborted))
 421                 aborted = true;
 422
 423         if (WARN_ON(!local->scan_req))
 424                 return;
 425
 426         scan_sdata = rcu_dereference_protected(local->scan_sdata,
 427                                                lockdep_is_held(&local->mtx));
 428
 429         if (hw_scan && !aborted &&
 430             !ieee80211_hw_check(&local->hw, SINGLE_SCAN_ON_ALL_BANDS) &&
 431             ieee80211_prep_hw_scan(scan_sdata)) {
 432                 int rc;
 433
 434                 rc = drv_hw_scan(local,
 435                         rcu_dereference_protected(local->scan_sdata,
 436                                                   lockdep_is_held(&local->mtx)),
 437                         local->hw_scan_req);
 438
 439                 if (rc == 0)
 440                         return;
 441
 442                 /* HW scan failed and is going to be reported as aborted,
 443                  * so clear old scan info.
 444                  */
 445                 memset(&local->scan_info, 0, sizeof(local->scan_info));
 446                 aborted = true;
 447         }
 448
 449         kfree(local->hw_scan_req);
 450         local->hw_scan_req = NULL;
 451
 452         scan_req = rcu_dereference_protected(local->scan_req,
 453                                              lockdep_is_held(&local->mtx));
 454
 455         RCU_INIT_POINTER(local->scan_req, NULL);
 456         RCU_INIT_POINTER(local->scan_sdata, NULL);
 457
 458         local->scanning = 0;
 459         local->scan_chandef.chan = NULL;
 460
 461         synchronize_rcu();
 462
 463         if (scan_req != local->int_scan_req) {
 464                 local->scan_info.aborted = aborted;
 465                 cfg80211_scan_done(scan_req, &local->scan_info);
 466         }
 467
 468         /* Set power back to normal operating levels. */
 469         ieee80211_hw_config(local, 0);
 470
 471         if (!hw_scan && was_scanning) {
 472                 ieee80211_configure_filter(local);
 473                 drv_sw_scan_complete(local, scan_sdata);
 474                 ieee80211_offchannel_return(local);
 475         }
 476
 477         ieee80211_recalc_idle(local);
 478
 479         ieee80211_mlme_notify_scan_completed(local);
 480         ieee80211_ibss_notify_scan_completed(local);
 481
 482         /* Requeue all the work that might have been ignored while
 483          * the scan was in progress; if there was none this will
 484          * just be a no-op for the particular interface.
 485          */
 486         list_for_each_entry_rcu(sdata, &local->interfaces, list) {
 487                 if (ieee80211_sdata_running(sdata))
 488                         wiphy_work_queue(sdata->local->hw.wiphy, &sdata->work);
 489         }
 490
 491         if (was_scanning)
 492                 ieee80211_start_next_roc(local);
 493 }
 494
 495 void ieee80211_scan_completed(struct ieee80211_hw *hw,
 496                               struct cfg80211_scan_info *info)
 497 {
 498         struct ieee80211_local *local = hw_to_local(hw);
 499
 500         trace_api_scan_completed(local, info->aborted);
 501
 502         set_bit(SCAN_COMPLETED, &local->scanning);
 503         if (info->aborted)
 504                 set_bit(SCAN_ABORTED, &local->scanning);
 505
 506         memcpy(&local->scan_info, info, sizeof(*info));
 507
 508         wiphy_delayed_work_queue(local->hw.wiphy, &local->scan_work, 0);
 509 }
 510 EXPORT_SYMBOL(ieee80211_scan_completed);
 511
 512 static int ieee80211_start_sw_scan(struct ieee80211_local *local,
 513                                    struct ieee80211_sub_if_data *sdata)
 514 {
 515         /* Software scan is not supported in multi-channel cases */
 516         if (local->use_chanctx)
 517                 return -EOPNOTSUPP;
 518
 519         /*
 520          * Hardware/driver doesn't support hw_scan, so use software
 521          * scanning instead. First send a nullfunc frame with power save
 522          * bit on so that AP will buffer the frames for us while we are not
 523          * listening, then send probe requests to each channel and wait for
 524          * the responses. After all channels are scanned, tune back to the
 525          * original channel and send a nullfunc frame with power save bit
 526          * off to trigger the AP to send us all the buffered frames.
 527          *
 528          * Note that while local->sw_scanning is true everything else but
 529          * nullfunc frames and probe requests will be dropped in
 530          * ieee80211_tx_h_check_assoc().
 531          */
 532         drv_sw_scan_start(local, sdata, local->scan_addr);
 533
 534         local->leave_oper_channel_time = jiffies;
 535         local->next_scan_state = SCAN_DECISION;
 536         local->scan_channel_idx = 0;
 537
 538         ieee80211_offchannel_stop_vifs(local);
 539
 540         /* ensure nullfunc is transmitted before leaving operating channel */
 541         ieee80211_flush_queues(local, NULL, false);
 542
 543         ieee80211_configure_filter(local);
 544
 545         /* We need to set power level at maximum rate for scanning. */
 546         ieee80211_hw_config(local, 0);
 547
 548         wiphy_delayed_work_queue(local->hw.wiphy, &local->scan_work, 0);
 549
 550         return 0;
 551 }
 552
 553 static bool __ieee80211_can_leave_ch(struct ieee80211_sub_if_data *sdata)
 554 {
 555         struct ieee80211_local *local = sdata->local;
 556         struct ieee80211_sub_if_data *sdata_iter;
 557
 558         if (!ieee80211_is_radar_required(local))
 559                 return true;
 560
 561         if (!regulatory_pre_cac_allowed(local->hw.wiphy))
 562                 return false;
 563
 564         mutex_lock(&local->iflist_mtx);
 565         list_for_each_entry(sdata_iter, &local->interfaces, list) {
 566                 if (sdata_iter->wdev.cac_started) {
 567                         mutex_unlock(&local->iflist_mtx);
 568                         return false;
 569                 }
 570         }
 571         mutex_unlock(&local->iflist_mtx);
 572
 573         return true;
 574 }
 575
 576 static bool ieee80211_can_scan(struct ieee80211_local *local,
 577                                struct ieee80211_sub_if_data *sdata)
 578 {
 579         if (!__ieee80211_can_leave_ch(sdata))
 580                 return false;
 581
 582         if (!list_empty(&local->roc_list))
 583                 return false;
 584
 585         if (sdata->vif.type == NL80211_IFTYPE_STATION &&
 586             sdata->u.mgd.flags & IEEE80211_STA_CONNECTION_POLL)
 587                 return false;
 588
 589         return true;
 590 }
 591
 592 void ieee80211_run_deferred_scan(struct ieee80211_local *local)
 593 {
 594         lockdep_assert_held(&local->mtx);
 595
 596         if (!local->scan_req || local->scanning)
 597                 return;
 598
 599         if (!ieee80211_can_scan(local,
 600                                 rcu_dereference_protected(
 601                                         local->scan_sdata,
 602                                         lockdep_is_held(&local->mtx))))
 603                 return;
 604
 605         wiphy_delayed_work_queue(local->hw.wiphy, &local->scan_work,
 606                                  round_jiffies_relative(0));
 607 }
 608
 609 static void ieee80211_send_scan_probe_req(struct ieee80211_sub_if_data *sdata,
 610                                           const u8 *src, const u8 *dst,
 611                                           const u8 *ssid, size_t ssid_len,
 612                                           const u8 *ie, size_t ie_len,
 613                                           u32 ratemask, u32 flags, u32 tx_flags,
 614                                           struct ieee80211_channel *channel)
 615 {
 616         struct sk_buff *skb;
 617
 618         skb = ieee80211_build_probe_req(sdata, src, dst, ratemask, channel,
 619                                         ssid, ssid_len,
 620                                         ie, ie_len, flags);
 621
 622         if (skb) {
 623                 if (flags & IEEE80211_PROBE_FLAG_RANDOM_SN) {
 624                         struct ieee80211_hdr *hdr = (void *)skb->data;
 625                         struct ieee80211_tx_info *info = IEEE80211_SKB_CB(skb);
 626                         u16 sn = get_random_u16();
 627
 628                         info->control.flags |= IEEE80211_TX_CTRL_NO_SEQNO;
 629                         hdr->seq_ctrl =
 630                                 cpu_to_le16(IEEE80211_SN_TO_SEQ(sn));
 631                 }
 632                 IEEE80211_SKB_CB(skb)->flags |= tx_flags;
 633                 ieee80211_tx_skb_tid_band(sdata, skb, 7, channel->band);
 634         }
 635 }
 636
 637 static void ieee80211_scan_state_send_probe(struct ieee80211_local *local,
 638                                             unsigned long *next_delay)
 639 {
 640         int i;
 641         struct ieee80211_sub_if_data *sdata;
 642         struct cfg80211_scan_request *scan_req;
 643         enum nl80211_band band = local->hw.conf.chandef.chan->band;
 644         u32 flags = 0, tx_flags;
 645
 646         scan_req = rcu_dereference_protected(local->scan_req,
 647                                              lockdep_is_held(&local->mtx));
 648
 649         tx_flags = IEEE80211_TX_INTFL_OFFCHAN_TX_OK;
 650         if (scan_req->no_cck)
 651                 tx_flags |= IEEE80211_TX_CTL_NO_CCK_RATE;
 652         if (scan_req->flags & NL80211_SCAN_FLAG_MIN_PREQ_CONTENT)
 653                 flags |= IEEE80211_PROBE_FLAG_MIN_CONTENT;
 654         if (scan_req->flags & NL80211_SCAN_FLAG_RANDOM_SN)
 655                 flags |= IEEE80211_PROBE_FLAG_RANDOM_SN;
 656
 657         sdata = rcu_dereference_protected(local->scan_sdata,
 658                                           lockdep_is_held(&local->mtx));
 659
 660         for (i = 0; i < scan_req->n_ssids; i++)
 661                 ieee80211_send_scan_probe_req(
 662                         sdata, local->scan_addr, scan_req->bssid,
 663                         scan_req->ssids[i].ssid, scan_req->ssids[i].ssid_len,
 664                         scan_req->ie, scan_req->ie_len,
 665                         scan_req->rates[band], flags,
 666                         tx_flags, local->hw.conf.chandef.chan);
 667
 668         /*
 669          * After sending probe requests, wait for probe responses
 670          * on the channel.
 671          */
 672         *next_delay = IEEE80211_CHANNEL_TIME;
 673         local->next_scan_state = SCAN_DECISION;
 674 }
 675
 676 static int __ieee80211_start_scan(struct ieee80211_sub_if_data *sdata,
 677                                   struct cfg80211_scan_request *req)
 678 {
 679         struct ieee80211_local *local = sdata->local;
 680         bool hw_scan = local->ops->hw_scan;
 681         int rc;
 682
 683         lockdep_assert_held(&local->mtx);
 684
 685         if (local->scan_req)
 686                 return -EBUSY;
 687
 688         if (!__ieee80211_can_leave_ch(sdata))
 689                 return -EBUSY;
 690
 691         if (!ieee80211_can_scan(local, sdata)) {
 692                 /* wait for the work to finish/time out */
 693                 rcu_assign_pointer(local->scan_req, req);
 694                 rcu_assign_pointer(local->scan_sdata, sdata);
 695                 return 0;
 696         }
 697
 698  again:
 699         if (hw_scan) {
 700                 u8 *ies;
 701
 702                 local->hw_scan_ies_bufsize = local->scan_ies_len + req->ie_len;
 703
 704                 if (ieee80211_hw_check(&local->hw, SINGLE_SCAN_ON_ALL_BANDS)) {
 705                         int i, n_bands = 0;
 706                         u8 bands_counted = 0;
 707
 708                         for (i = 0; i < req->n_channels; i++) {
 709                                 if (bands_counted & BIT(req->channels[i]->band))
 710                                         continue;
 711                                 bands_counted |= BIT(req->channels[i]->band);
 712                                 n_bands++;
 713                         }
 714
 715                         local->hw_scan_ies_bufsize *= n_bands;
 716                 }
 717
 718                 local->hw_scan_req = kmalloc(
 719                                 sizeof(*local->hw_scan_req) +
 720                                 req->n_channels * sizeof(req->channels[0]) +
 721                                 local->hw_scan_ies_bufsize, GFP_KERNEL);
 722                 if (!local->hw_scan_req)
 723                         return -ENOMEM;
 724
 725                 local->hw_scan_req->req.ssids = req->ssids;
 726                 local->hw_scan_req->req.n_ssids = req->n_ssids;
 727                 ies = (u8 *)local->hw_scan_req +
 728                         sizeof(*local->hw_scan_req) +
 729                         req->n_channels * sizeof(req->channels[0]);
 730                 local->hw_scan_req->req.ie = ies;
 731                 local->hw_scan_req->req.flags = req->flags;
 732                 eth_broadcast_addr(local->hw_scan_req->req.bssid);
 733                 local->hw_scan_req->req.duration = req->duration;
 734                 local->hw_scan_req->req.duration_mandatory =
 735                         req->duration_mandatory;
 736
 737                 local->hw_scan_band = 0;
 738                 local->hw_scan_req->req.n_6ghz_params = req->n_6ghz_params;
 739                 local->hw_scan_req->req.scan_6ghz_params =
 740                         req->scan_6ghz_params;
 741                 local->hw_scan_req->req.scan_6ghz = req->scan_6ghz;
 742
 743                 /*
 744                  * After allocating local->hw_scan_req, we must
 745                  * go through until ieee80211_prep_hw_scan(), so
 746                  * anything that might be changed here and leave
 747                  * this function early must not go after this
 748                  * allocation.
 749                  */
 750         }
 751
 752         rcu_assign_pointer(local->scan_req, req);
 753         rcu_assign_pointer(local->scan_sdata, sdata);
 754
 755         if (req->flags & NL80211_SCAN_FLAG_RANDOM_ADDR)
 756                 get_random_mask_addr(local->scan_addr,
 757                                      req->mac_addr,
 758                                      req->mac_addr_mask);
 759         else
 760                 memcpy(local->scan_addr, sdata->vif.addr, ETH_ALEN);
 761
 762         if (hw_scan) {
 763                 __set_bit(SCAN_HW_SCANNING, &local->scanning);
 764         } else if ((req->n_channels == 1) &&
 765                    (req->channels[0] == local->_oper_chandef.chan)) {
 766                 /*
 767                  * If we are scanning only on the operating channel
 768                  * then we do not need to stop normal activities
 769                  */
 770                 unsigned long next_delay;
 771
 772                 __set_bit(SCAN_ONCHANNEL_SCANNING, &local->scanning);
 773
 774                 ieee80211_recalc_idle(local);
 775
 776                 /* Notify driver scan is starting, keep order of operations
 777                  * same as normal software scan, in case that matters. */
 778                 drv_sw_scan_start(local, sdata, local->scan_addr);
 779
 780                 ieee80211_configure_filter(local); /* accept probe-responses */
 781
 782                 /* We need to ensure power level is at max for scanning. */
 783                 ieee80211_hw_config(local, 0);
 784
 785                 if ((req->channels[0]->flags & (IEEE80211_CHAN_NO_IR |
 786                                                 IEEE80211_CHAN_RADAR)) ||
 787                     !req->n_ssids) {
 788                         next_delay = IEEE80211_PASSIVE_CHANNEL_TIME;
 789                         if (req->n_ssids)
 790                                 set_bit(SCAN_BEACON_WAIT, &local->scanning);
 791                 } else {
 792                         ieee80211_scan_state_send_probe(local, &next_delay);
 793                         next_delay = IEEE80211_CHANNEL_TIME;
 794                 }
 795
 796                 /* Now, just wait a bit and we are all done! */
 797                 wiphy_delayed_work_queue(local->hw.wiphy, &local->scan_work,
 798                                          next_delay);
 799                 return 0;
 800         } else {
 801                 /* Do normal software scan */
 802                 __set_bit(SCAN_SW_SCANNING, &local->scanning);
 803         }
 804
 805         ieee80211_recalc_idle(local);
 806
 807         if (hw_scan) {
 808                 WARN_ON(!ieee80211_prep_hw_scan(sdata));
 809                 rc = drv_hw_scan(local, sdata, local->hw_scan_req);
 810         } else {
 811                 rc = ieee80211_start_sw_scan(local, sdata);
 812         }
 813
 814         if (rc) {
 815                 kfree(local->hw_scan_req);
 816                 local->hw_scan_req = NULL;
 817                 local->scanning = 0;
 818
 819                 ieee80211_recalc_idle(local);
 820
 821                 local->scan_req = NULL;
 822                 RCU_INIT_POINTER(local->scan_sdata, NULL);
 823         }
 824
 825         if (hw_scan && rc == 1) {
 826                 /*
 827                  * we can't fall back to software for P2P-GO
 828                  * as it must update NoA etc.
 829                  */
 830                 if (ieee80211_vif_type_p2p(&sdata->vif) ==
 831                                 NL80211_IFTYPE_P2P_GO)
 832                         return -EOPNOTSUPP;
 833                 hw_scan = false;
 834                 goto again;
 835         }
 836
 837         return rc;
 838 }
 839
 840 static unsigned long
 841 ieee80211_scan_get_channel_time(struct ieee80211_channel *chan)
 842 {
 843         /*
 844          * TODO: channel switching also consumes quite some time,
 845          * add that delay as well to get a better estimation
 846          */
 847         if (chan->flags & (IEEE80211_CHAN_NO_IR | IEEE80211_CHAN_RADAR))
 848                 return IEEE80211_PASSIVE_CHANNEL_TIME;
 849         return IEEE80211_PROBE_DELAY + IEEE80211_CHANNEL_TIME;
 850 }
 851
 852 static void ieee80211_scan_state_decision(struct ieee80211_local *local,
 853                                           unsigned long *next_delay)
 854 {
 855         bool associated = false;
 856         bool tx_empty = true;
 857         bool bad_latency;
 858         struct ieee80211_sub_if_data *sdata;
 859         struct ieee80211_channel *next_chan;
 860         enum mac80211_scan_state next_scan_state;
 861         struct cfg80211_scan_request *scan_req;
 862
 863         /*
 864          * check if at least one STA interface is associated,
 865          * check if at least one STA interface has pending tx frames
 866          * and grab the lowest used beacon interval
 867          */
 868         mutex_lock(&local->iflist_mtx);
 869         list_for_each_entry(sdata, &local->interfaces, list) {
 870                 if (!ieee80211_sdata_running(sdata))
 871                         continue;
 872
 873                 if (sdata->vif.type == NL80211_IFTYPE_STATION) {
 874                         if (sdata->u.mgd.associated) {
 875                                 associated = true;
 876
 877                                 if (!qdisc_all_tx_empty(sdata->dev)) {
 878                                         tx_empty = false;
 879                                         break;
 880                                 }
 881                         }
 882                 }
 883         }
 884         mutex_unlock(&local->iflist_mtx);
 885
 886         scan_req = rcu_dereference_protected(local->scan_req,
 887                                              lockdep_is_held(&local->mtx));
 888
 889         next_chan = scan_req->channels[local->scan_channel_idx];
 890
 891         /*
 892          * we're currently scanning a different channel, let's
 893          * see if we can scan another channel without interfering
 894          * with the current traffic situation.
 895          *
 896          * Keep good latency, do not stay off-channel more than 125 ms.
 897          */
 898
 899         bad_latency = time_after(jiffies +
 900                                  ieee80211_scan_get_channel_time(next_chan),
 901                                  local->leave_oper_channel_time + HZ / 8);
 902
 903         if (associated && !tx_empty) {
 904                 if (scan_req->flags & NL80211_SCAN_FLAG_LOW_PRIORITY)
 905                         next_scan_state = SCAN_ABORT;
 906                 else
 907                         next_scan_state = SCAN_SUSPEND;
 908         } else if (associated && bad_latency) {
 909                 next_scan_state = SCAN_SUSPEND;
 910         } else {
 911                 next_scan_state = SCAN_SET_CHANNEL;
 912         }
 913
 914         local->next_scan_state = next_scan_state;
 915
 916         *next_delay = 0;
 917 }
 918
 919 static void ieee80211_scan_state_set_channel(struct ieee80211_local *local,
 920                                              unsigned long *next_delay)
 921 {
 922         int skip;
 923         struct ieee80211_channel *chan;
 924         enum nl80211_bss_scan_width oper_scan_width;
 925         struct cfg80211_scan_request *scan_req;
 926
 927         scan_req = rcu_dereference_protected(local->scan_req,
 928                                              lockdep_is_held(&local->mtx));
 929
 930         skip = 0;
 931         chan = scan_req->channels[local->scan_channel_idx];
 932
 933         local->scan_chandef.chan = chan;
 934         local->scan_chandef.center_freq1 = chan->center_freq;
 935         local->scan_chandef.freq1_offset = chan->freq_offset;
 936         local->scan_chandef.center_freq2 = 0;
 937
 938         /* For scanning on the S1G band, ignore scan_width (which is constant
 939          * across all channels) for now since channel width is specific to each
 940          * channel. Detect the required channel width here and likely revisit
 941          * later. Maybe scan_width could be used to build the channel scan list?
 942          */
 943         if (chan->band == NL80211_BAND_S1GHZ) {
 944                 local->scan_chandef.width = ieee80211_s1g_channel_width(chan);
 945                 goto set_channel;
 946         }
 947
 948         switch (scan_req->scan_width) {
 949         case NL80211_BSS_CHAN_WIDTH_5:
 950                 local->scan_chandef.width = NL80211_CHAN_WIDTH_5;
 951                 break;
 952         case NL80211_BSS_CHAN_WIDTH_10:
 953                 local->scan_chandef.width = NL80211_CHAN_WIDTH_10;
 954                 break;
 955         default:
 956         case NL80211_BSS_CHAN_WIDTH_20:
 957                 /* If scanning on oper channel, use whatever channel-type
 958                  * is currently in use.
 959                  */
 960                 oper_scan_width = cfg80211_chandef_to_scan_width(
 961                                         &local->_oper_chandef);
 962                 if (chan == local->_oper_chandef.chan &&
 963                     oper_scan_width == scan_req->scan_width)
 964                         local->scan_chandef = local->_oper_chandef;
 965                 else
 966                         local->scan_chandef.width = NL80211_CHAN_WIDTH_20_NOHT;
 967                 break;
 968         case NL80211_BSS_CHAN_WIDTH_1:
 969         case NL80211_BSS_CHAN_WIDTH_2:
 970                 /* shouldn't get here, S1G handled above */
 971                 WARN_ON(1);
 972                 break;
 973         }
 974
 975 set_channel:
 976         if (ieee80211_hw_config(local, IEEE80211_CONF_CHANGE_CHANNEL))
 977                 skip = 1;
 978
 979         /* advance state machine to next channel/band */
 980         local->scan_channel_idx++;
 981
 982         if (skip) {
 983                 /* if we skip this channel return to the decision state */
 984                 local->next_scan_state = SCAN_DECISION;
 985                 return;
 986         }
 987
 988         /*
 989          * Probe delay is used to update the NAV, cf. 11.1.3.2.2
 990          * (which unfortunately doesn't say _why_ step a) is done,
 991          * but it waits for the probe delay or until a frame is
 992          * received - and the received frame would update the NAV).
 993          * For now, we do not support waiting until a frame is
 994          * received.
 995          *
 996          * In any case, it is not necessary for a passive scan.
 997          */
 998         if ((chan->flags & (IEEE80211_CHAN_NO_IR | IEEE80211_CHAN_RADAR)) ||
 999             !scan_req->n_ssids) {
1000                 *next_delay = IEEE80211_PASSIVE_CHANNEL_TIME;
1001                 local->next_scan_state = SCAN_DECISION;
1002                 if (scan_req->n_ssids)
1003                         set_bit(SCAN_BEACON_WAIT, &local->scanning);
1004                 return;
1005         }
1006
1007         /* active scan, send probes */
1008         *next_delay = IEEE80211_PROBE_DELAY;
1009         local->next_scan_state = SCAN_SEND_PROBE;
1010 }
1011
1012 static void ieee80211_scan_state_suspend(struct ieee80211_local *local,
1013                                          unsigned long *next_delay)
1014 {
1015         /* switch back to the operating channel */
1016         local->scan_chandef.chan = NULL;
1017         ieee80211_hw_config(local, IEEE80211_CONF_CHANGE_CHANNEL);
1018
1019         /* disable PS */
1020         ieee80211_offchannel_return(local);
1021
1022         *next_delay = HZ / 5;
1023         /* afterwards, resume scan & go to next channel */
1024         local->next_scan_state = SCAN_RESUME;
1025 }
1026
1027 static void ieee80211_scan_state_resume(struct ieee80211_local *local,
1028                                         unsigned long *next_delay)
1029 {
1030         ieee80211_offchannel_stop_vifs(local);
1031
1032         if (local->ops->flush) {
1033                 ieee80211_flush_queues(local, NULL, false);
1034                 *next_delay = 0;
1035         } else
1036                 *next_delay = HZ / 10;
1037
1038         /* remember when we left the operating channel */
1039         local->leave_oper_channel_time = jiffies;
1040
1041         /* advance to the next channel to be scanned */
1042         local->next_scan_state = SCAN_SET_CHANNEL;
1043 }
1044
1045 void ieee80211_scan_work(struct wiphy *wiphy, struct wiphy_work *work)
1046 {
1047         struct ieee80211_local *local =
1048                 container_of(work, struct ieee80211_local, scan_work.work);
1049         struct ieee80211_sub_if_data *sdata;
1050         struct cfg80211_scan_request *scan_req;
1051         unsigned long next_delay = 0;
1052         bool aborted;
1053
1054         mutex_lock(&local->mtx);
1055
1056         if (!ieee80211_can_run_worker(local)) {
1057                 aborted = true;
1058                 goto out_complete;
1059         }
1060
1061         sdata = rcu_dereference_protected(local->scan_sdata,
1062                                           lockdep_is_held(&local->mtx));
1063         scan_req = rcu_dereference_protected(local->scan_req,
1064                                              lockdep_is_held(&local->mtx));
1065
1066         /* When scanning on-channel, the first-callback means completed. */
1067         if (test_bit(SCAN_ONCHANNEL_SCANNING, &local->scanning)) {
1068                 aborted = test_and_clear_bit(SCAN_ABORTED, &local->scanning);
1069                 goto out_complete;
1070         }
1071
1072         if (test_and_clear_bit(SCAN_COMPLETED, &local->scanning)) {
1073                 aborted = test_and_clear_bit(SCAN_ABORTED, &local->scanning);
1074                 goto out_complete;
1075         }
1076
1077         if (!sdata || !scan_req)
1078                 goto out;
1079
1080         if (!local->scanning) {
1081                 int rc;
1082
1083                 RCU_INIT_POINTER(local->scan_req, NULL);
1084                 RCU_INIT_POINTER(local->scan_sdata, NULL);
1085
1086                 rc = __ieee80211_start_scan(sdata, scan_req);
1087                 if (rc) {
1088                         /* need to complete scan in cfg80211 */
1089                         rcu_assign_pointer(local->scan_req, scan_req);
1090                         aborted = true;
1091                         goto out_complete;
1092                 } else
1093                         goto out;
1094         }
1095
1096         clear_bit(SCAN_BEACON_WAIT, &local->scanning);
1097
1098         /*
1099          * as long as no delay is required advance immediately
1100          * without scheduling a new work
1101          */
1102         do {
1103                 if (!ieee80211_sdata_running(sdata)) {
1104                         aborted = true;
1105                         goto out_complete;
1106                 }
1107
1108                 if (test_and_clear_bit(SCAN_BEACON_DONE, &local->scanning) &&
1109                     local->next_scan_state == SCAN_DECISION)
1110                         local->next_scan_state = SCAN_SEND_PROBE;
1111
1112                 switch (local->next_scan_state) {
1113                 case SCAN_DECISION:
1114                         /* if no more bands/channels left, complete scan */
1115                         if (local->scan_channel_idx >= scan_req->n_channels) {
1116                                 aborted = false;
1117                                 goto out_complete;
1118                         }
1119                         ieee80211_scan_state_decision(local, &next_delay);
1120                         break;
1121                 case SCAN_SET_CHANNEL:
1122                         ieee80211_scan_state_set_channel(local, &next_delay);
1123                         break;
1124                 case SCAN_SEND_PROBE:
1125                         ieee80211_scan_state_send_probe(local, &next_delay);
1126                         break;
1127                 case SCAN_SUSPEND:
1128                         ieee80211_scan_state_suspend(local, &next_delay);
1129                         break;
1130                 case SCAN_RESUME:
1131                         ieee80211_scan_state_resume(local, &next_delay);
1132                         break;
1133                 case SCAN_ABORT:
1134                         aborted = true;
1135                         goto out_complete;
1136                 }
1137         } while (next_delay == 0);
1138
1139         wiphy_delayed_work_queue(local->hw.wiphy, &local->scan_work,
1140                                  next_delay);
1141         goto out;
1142
1143 out_complete:
1144         __ieee80211_scan_completed(&local->hw, aborted);
1145 out:
1146         mutex_unlock(&local->mtx);
1147 }
1148
1149 int ieee80211_request_scan(struct ieee80211_sub_if_data *sdata,
1150                            struct cfg80211_scan_request *req)
1151 {
1152         int res;
1153
1154         mutex_lock(&sdata->local->mtx);
1155         res = __ieee80211_start_scan(sdata, req);
1156         mutex_unlock(&sdata->local->mtx);
1157
1158         return res;
1159 }
1160
1161 int ieee80211_request_ibss_scan(struct ieee80211_sub_if_data *sdata,
1162                                 const u8 *ssid, u8 ssid_len,
1163                                 struct ieee80211_channel **channels,
1164                                 unsigned int n_channels,
1165                                 enum nl80211_bss_scan_width scan_width)
1166 {
1167         struct ieee80211_local *local = sdata->local;
1168         int ret = -EBUSY, i, n_ch = 0;
1169         enum nl80211_band band;
1170
1171         mutex_lock(&local->mtx);
1172
1173         /* busy scanning */
1174         if (local->scan_req)
1175                 goto unlock;
1176
1177         /* fill internal scan request */
1178         if (!channels) {
1179                 int max_n;
1180
1181                 for (band = 0; band < NUM_NL80211_BANDS; band++) {
1182                         if (!local->hw.wiphy->bands[band] ||
1183                             band == NL80211_BAND_6GHZ)
1184                                 continue;
1185
1186                         max_n = local->hw.wiphy->bands[band]->n_channels;
1187                         for (i = 0; i < max_n; i++) {
1188                                 struct ieee80211_channel *tmp_ch =
1189                                     &local->hw.wiphy->bands[band]->channels[i];
1190
1191                                 if (tmp_ch->flags & (IEEE80211_CHAN_NO_IR |
1192                                                      IEEE80211_CHAN_DISABLED))
1193                                         continue;
1194
1195                                 local->int_scan_req->channels[n_ch] = tmp_ch;
1196                                 n_ch++;
1197                         }
1198                 }
1199
1200                 if (WARN_ON_ONCE(n_ch == 0))
1201                         goto unlock;
1202
1203                 local->int_scan_req->n_channels = n_ch;
1204         } else {
1205                 for (i = 0; i < n_channels; i++) {
1206                         if (channels[i]->flags & (IEEE80211_CHAN_NO_IR |
1207                                                   IEEE80211_CHAN_DISABLED))
1208                                 continue;
1209
1210                         local->int_scan_req->channels[n_ch] = channels[i];
1211                         n_ch++;
1212                 }
1213
1214                 if (WARN_ON_ONCE(n_ch == 0))
1215                         goto unlock;
1216
1217                 local->int_scan_req->n_channels = n_ch;
1218         }
1219
1220         local->int_scan_req->ssids = &local->scan_ssid;
1221         local->int_scan_req->n_ssids = 1;
1222         local->int_scan_req->scan_width = scan_width;
1223         memcpy(local->int_scan_req->ssids[0].ssid, ssid, IEEE80211_MAX_SSID_LEN);
1224         local->int_scan_req->ssids[0].ssid_len = ssid_len;
1225
1226         ret = __ieee80211_start_scan(sdata, sdata->local->int_scan_req);
1227  unlock:
1228         mutex_unlock(&local->mtx);
1229         return ret;
1230 }
1231
1232 void ieee80211_scan_cancel(struct ieee80211_local *local)
1233 {
1234         /* ensure a new scan cannot be queued */
1235         lockdep_assert_wiphy(local->hw.wiphy);
1236
1237         /*
1238          * We are canceling software scan, or deferred scan that was not
1239          * yet really started (see __ieee80211_start_scan ).
1240          *
1241          * Regarding hardware scan:
1242          * - we can not call  __ieee80211_scan_completed() as when
1243          *   SCAN_HW_SCANNING bit is set this function change
1244          *   local->hw_scan_req to operate on 5G band, what race with
1245          *   driver which can use local->hw_scan_req
1246          *
1247          * - we can not cancel scan_work since driver can schedule it
1248          *   by ieee80211_scan_completed(..., true) to finish scan
1249          *
1250          * Hence we only call the cancel_hw_scan() callback, but the low-level
1251          * driver is still responsible for calling ieee80211_scan_completed()
1252          * after the scan was completed/aborted.
1253          */
1254
1255         mutex_lock(&local->mtx);
1256         if (!local->scan_req)
1257                 goto out;
1258
1259         /*
1260          * We have a scan running and the driver already reported completion,
1261          * but the worker hasn't run yet or is stuck on the mutex - mark it as
1262          * cancelled.
1263          */
1264         if (test_bit(SCAN_HW_SCANNING, &local->scanning) &&
1265             test_bit(SCAN_COMPLETED, &local->scanning)) {
1266                 set_bit(SCAN_HW_CANCELLED, &local->scanning);
1267                 goto out;
1268         }
1269
1270         if (test_bit(SCAN_HW_SCANNING, &local->scanning)) {
1271                 /*
1272                  * Make sure that __ieee80211_scan_completed doesn't trigger a
1273                  * scan on another band.
1274                  */
1275                 set_bit(SCAN_HW_CANCELLED, &local->scanning);
1276                 if (local->ops->cancel_hw_scan)
1277                         drv_cancel_hw_scan(local,
1278                                 rcu_dereference_protected(local->scan_sdata,
1279                                                 lockdep_is_held(&local->mtx)));
1280                 goto out;
1281         }
1282
1283         wiphy_delayed_work_cancel(local->hw.wiphy, &local->scan_work);
1284         /* and clean up */
1285         memset(&local->scan_info, 0, sizeof(local->scan_info));
1286         __ieee80211_scan_completed(&local->hw, true);
1287 out:
1288         mutex_unlock(&local->mtx);
1289 }
1290
1291 int __ieee80211_request_sched_scan_start(struct ieee80211_sub_if_data *sdata,
1292                                         struct cfg80211_sched_scan_request *req)
1293 {
1294         struct ieee80211_local *local = sdata->local;
1295         struct ieee80211_scan_ies sched_scan_ies = {};
1296         struct cfg80211_chan_def chandef;
1297         int ret, i, iebufsz, num_bands = 0;
1298         u32 rate_masks[NUM_NL80211_BANDS] = {};
1299         u8 bands_used = 0;
1300         u8 *ie;
1301         u32 flags = 0;
1302
1303         iebufsz = local->scan_ies_len + req->ie_len;
1304
1305         lockdep_assert_held(&local->mtx);
1306
1307         if (!local->ops->sched_scan_start)
1308                 return -ENOTSUPP;
1309
1310         for (i = 0; i < NUM_NL80211_BANDS; i++) {
1311                 if (local->hw.wiphy->bands[i]) {
1312                         bands_used |= BIT(i);
1313                         rate_masks[i] = (u32) -1;
1314                         num_bands++;
1315                 }
1316         }
1317
1318         if (req->flags & NL80211_SCAN_FLAG_MIN_PREQ_CONTENT)
1319                 flags |= IEEE80211_PROBE_FLAG_MIN_CONTENT;
1320
1321         ie = kcalloc(iebufsz, num_bands, GFP_KERNEL);
1322         if (!ie) {
1323                 ret = -ENOMEM;
1324                 goto out;
1325         }
1326
1327         ieee80211_prepare_scan_chandef(&chandef, req->scan_width);
1328
1329         ieee80211_build_preq_ies(sdata, ie, num_bands * iebufsz,
1330                                  &sched_scan_ies, req->ie,
1331                                  req->ie_len, bands_used, rate_masks, &chandef,
1332                                  flags);
1333
1334         ret = drv_sched_scan_start(local, sdata, req, &sched_scan_ies);
1335         if (ret == 0) {
1336                 rcu_assign_pointer(local->sched_scan_sdata, sdata);
1337                 rcu_assign_pointer(local->sched_scan_req, req);
1338         }
1339
1340         kfree(ie);
1341
1342 out:
1343         if (ret) {
1344                 /* Clean in case of failure after HW restart or upon resume. */
1345                 RCU_INIT_POINTER(local->sched_scan_sdata, NULL);
1346                 RCU_INIT_POINTER(local->sched_scan_req, NULL);
1347         }
1348
1349         return ret;
1350 }
1351
1352 int ieee80211_request_sched_scan_start(struct ieee80211_sub_if_data *sdata,
1353                                        struct cfg80211_sched_scan_request *req)
1354 {
1355         struct ieee80211_local *local = sdata->local;
1356         int ret;
1357
1358         mutex_lock(&local->mtx);
1359
1360         if (rcu_access_pointer(local->sched_scan_sdata)) {
1361                 mutex_unlock(&local->mtx);
1362                 return -EBUSY;
1363         }
1364
1365         ret = __ieee80211_request_sched_scan_start(sdata, req);
1366
1367         mutex_unlock(&local->mtx);
1368         return ret;
1369 }
1370
1371 int ieee80211_request_sched_scan_stop(struct ieee80211_local *local)
1372 {
1373         struct ieee80211_sub_if_data *sched_scan_sdata;
1374         int ret = -ENOENT;
1375
1376         mutex_lock(&local->mtx);
1377
1378         if (!local->ops->sched_scan_stop) {
1379                 ret = -ENOTSUPP;
1380                 goto out;
1381         }
1382
1383         /* We don't want to restart sched scan anymore. */
1384         RCU_INIT_POINTER(local->sched_scan_req, NULL);
1385
1386         sched_scan_sdata = rcu_dereference_protected(local->sched_scan_sdata,
1387                                                 lockdep_is_held(&local->mtx));
1388         if (sched_scan_sdata) {
1389                 ret = drv_sched_scan_stop(local, sched_scan_sdata);
1390                 if (!ret)
1391                         RCU_INIT_POINTER(local->sched_scan_sdata, NULL);
1392         }
1393 out:
1394         mutex_unlock(&local->mtx);
1395
1396         return ret;
1397 }
1398
1399 void ieee80211_sched_scan_results(struct ieee80211_hw *hw)
1400 {
1401         struct ieee80211_local *local = hw_to_local(hw);
1402
1403         trace_api_sched_scan_results(local);
1404
1405         cfg80211_sched_scan_results(hw->wiphy, 0);
1406 }
1407 EXPORT_SYMBOL(ieee80211_sched_scan_results);
1408
1409 void ieee80211_sched_scan_end(struct ieee80211_local *local)
1410 {
1411         mutex_lock(&local->mtx);
1412
1413         if (!rcu_access_pointer(local->sched_scan_sdata)) {
1414                 mutex_unlock(&local->mtx);
1415                 return;
1416         }
1417
1418         RCU_INIT_POINTER(local->sched_scan_sdata, NULL);
1419
1420         /* If sched scan was aborted by the driver. */
1421         RCU_INIT_POINTER(local->sched_scan_req, NULL);
1422
1423         mutex_unlock(&local->mtx);
1424
1425         cfg80211_sched_scan_stopped_locked(local->hw.wiphy, 0);
1426 }
1427
1428 void ieee80211_sched_scan_stopped_work(struct wiphy *wiphy,
1429                                        struct wiphy_work *work)
1430 {
1431         struct ieee80211_local *local =
1432                 container_of(work, struct ieee80211_local,
1433                              sched_scan_stopped_work);
1434
1435         ieee80211_sched_scan_end(local);
1436 }
1437
1438 void ieee80211_sched_scan_stopped(struct ieee80211_hw *hw)
1439 {
1440         struct ieee80211_local *local = hw_to_local(hw);
1441
1442         trace_api_sched_scan_stopped(local);
1443
1444         /*
1445          * this shouldn't really happen, so for simplicity
1446          * simply ignore it, and let mac80211 reconfigure
1447          * the sched scan later on.
1448          */
1449         if (local->in_reconfig)
1450                 return;
1451
1452         wiphy_work_queue(hw->wiphy, &local->sched_scan_stopped_work);
1453 }
1454 EXPORT_SYMBOL(ieee80211_sched_scan_stopped);