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.chan = channel;
 191
 192         rcu_read_lock();
 193         scan_sdata = rcu_dereference(local->scan_sdata);
 194         if (scan_sdata && scan_sdata->vif.type == NL80211_IFTYPE_STATION &&
 195             scan_sdata->vif.cfg.assoc &&
 196             ieee80211_have_rx_timestamp(rx_status)) {
 197                 struct ieee80211_bss_conf *link_conf = NULL;
 198
 199                 /* for an MLO connection, set the TSF data only in case we have
 200                  * an indication on which of the links the frame was received
 201                  */
 202                 if (ieee80211_vif_is_mld(&scan_sdata->vif)) {
 203                         if (rx_status->link_valid) {
 204                                 s8 link_id = rx_status->link_id;
 205
 206                                 link_conf =
 207                                         rcu_dereference(scan_sdata->vif.link_conf[link_id]);
 208                         }
 209                 } else {
 210                         link_conf = &scan_sdata->vif.bss_conf;
 211                 }
 212
 213                 if (link_conf) {
 214                         bss_meta.parent_tsf =
 215                                 ieee80211_calculate_rx_timestamp(local,
 216                                                                  rx_status,
 217                                                                  len + FCS_LEN,
 218                                                                  24);
 219
 220                         ether_addr_copy(bss_meta.parent_bssid,
 221                                         link_conf->bssid);
 222                 }
 223         }
 224         rcu_read_unlock();
 225
 226         cbss = cfg80211_inform_bss_frame_data(local->hw.wiphy, &bss_meta,
 227                                               mgmt, len, GFP_ATOMIC);
 228         if (!cbss)
 229                 return NULL;
 230
 231         /* In case the signal is invalid update the status */
 232         signal_valid = channel == cbss->channel;
 233         if (!signal_valid)
 234                 rx_status->flag |= RX_FLAG_NO_SIGNAL_VAL;
 235
 236         return (void *)cbss->priv;
 237 }
 238
 239 static bool ieee80211_scan_accept_presp(struct ieee80211_sub_if_data *sdata,
 240                                         u32 scan_flags, const u8 *da)
 241 {
 242         if (!sdata)
 243                 return false;
 244         /* accept broadcast for OCE */
 245         if (scan_flags & NL80211_SCAN_FLAG_ACCEPT_BCAST_PROBE_RESP &&
 246             is_broadcast_ether_addr(da))
 247                 return true;
 248         if (scan_flags & NL80211_SCAN_FLAG_RANDOM_ADDR)
 249                 return true;
 250         return ether_addr_equal(da, sdata->vif.addr);
 251 }
 252
 253 void ieee80211_scan_rx(struct ieee80211_local *local, struct sk_buff *skb)
 254 {
 255         struct ieee80211_rx_status *rx_status = IEEE80211_SKB_RXCB(skb);
 256         struct ieee80211_sub_if_data *sdata1, *sdata2;
 257         struct ieee80211_mgmt *mgmt = (void *)skb->data;
 258         struct ieee80211_bss *bss;
 259         struct ieee80211_channel *channel;
 260         size_t min_hdr_len = offsetof(struct ieee80211_mgmt,
 261                                       u.probe_resp.variable);
 262
 263         if (!ieee80211_is_probe_resp(mgmt->frame_control) &&
 264             !ieee80211_is_beacon(mgmt->frame_control) &&
 265             !ieee80211_is_s1g_beacon(mgmt->frame_control))
 266                 return;
 267
 268         if (ieee80211_is_s1g_beacon(mgmt->frame_control)) {
 269                 if (ieee80211_is_s1g_short_beacon(mgmt->frame_control))
 270                         min_hdr_len = offsetof(struct ieee80211_ext,
 271                                                u.s1g_short_beacon.variable);
 272                 else
 273                         min_hdr_len = offsetof(struct ieee80211_ext,
 274                                                u.s1g_beacon);
 275         }
 276
 277         if (skb->len < min_hdr_len)
 278                 return;
 279
 280         sdata1 = rcu_dereference(local->scan_sdata);
 281         sdata2 = rcu_dereference(local->sched_scan_sdata);
 282
 283         if (likely(!sdata1 && !sdata2))
 284                 return;
 285
 286         if (test_and_clear_bit(SCAN_BEACON_WAIT, &local->scanning)) {
 287                 /*
 288                  * we were passive scanning because of radar/no-IR, but
 289                  * the beacon/proberesp rx gives us an opportunity to upgrade
 290                  * to active scan
 291                  */
 292                 set_bit(SCAN_BEACON_DONE, &local->scanning);
 293                 wiphy_delayed_work_queue(local->hw.wiphy, &local->scan_work, 0);
 294         }
 295
 296         if (ieee80211_is_probe_resp(mgmt->frame_control)) {
 297                 struct cfg80211_scan_request *scan_req;
 298                 struct cfg80211_sched_scan_request *sched_scan_req;
 299                 u32 scan_req_flags = 0, sched_scan_req_flags = 0;
 300
 301                 scan_req = rcu_dereference(local->scan_req);
 302                 sched_scan_req = rcu_dereference(local->sched_scan_req);
 303
 304                 if (scan_req)
 305                         scan_req_flags = scan_req->flags;
 306
 307                 if (sched_scan_req)
 308                         sched_scan_req_flags = sched_scan_req->flags;
 309
 310                 /* ignore ProbeResp to foreign address or non-bcast (OCE)
 311                  * unless scanning with randomised address
 312                  */
 313                 if (!ieee80211_scan_accept_presp(sdata1, scan_req_flags,
 314                                                  mgmt->da) &&
 315                     !ieee80211_scan_accept_presp(sdata2, sched_scan_req_flags,
 316                                                  mgmt->da))
 317                         return;
 318         }
 319
 320         channel = ieee80211_get_channel_khz(local->hw.wiphy,
 321                                         ieee80211_rx_status_to_khz(rx_status));
 322
 323         if (!channel || channel->flags & IEEE80211_CHAN_DISABLED)
 324                 return;
 325
 326         bss = ieee80211_bss_info_update(local, rx_status,
 327                                         mgmt, skb->len,
 328                                         channel);
 329         if (bss)
 330                 ieee80211_rx_bss_put(local, bss);
 331 }
 332
 333 static void ieee80211_prepare_scan_chandef(struct cfg80211_chan_def *chandef)
 334 {
 335         memset(chandef, 0, sizeof(*chandef));
 336
 337         chandef->width = NL80211_CHAN_WIDTH_20_NOHT;
 338 }
 339
 340 /* return false if no more work */
 341 static bool ieee80211_prep_hw_scan(struct ieee80211_sub_if_data *sdata)
 342 {
 343         struct ieee80211_local *local = sdata->local;
 344         struct cfg80211_scan_request *req;
 345         struct cfg80211_chan_def chandef;
 346         u8 bands_used = 0;
 347         int i, ielen, n_chans;
 348         u32 flags = 0;
 349
 350         req = rcu_dereference_protected(local->scan_req,
 351                                         lockdep_is_held(&local->hw.wiphy->mtx));
 352
 353         if (test_bit(SCAN_HW_CANCELLED, &local->scanning))
 354                 return false;
 355
 356         if (ieee80211_hw_check(&local->hw, SINGLE_SCAN_ON_ALL_BANDS)) {
 357                 for (i = 0; i < req->n_channels; i++) {
 358                         local->hw_scan_req->req.channels[i] = req->channels[i];
 359                         bands_used |= BIT(req->channels[i]->band);
 360                 }
 361
 362                 n_chans = req->n_channels;
 363         } else {
 364                 do {
 365                         if (local->hw_scan_band == NUM_NL80211_BANDS)
 366                                 return false;
 367
 368                         n_chans = 0;
 369
 370                         for (i = 0; i < req->n_channels; i++) {
 371                                 if (req->channels[i]->band !=
 372                                     local->hw_scan_band)
 373                                         continue;
 374                                 local->hw_scan_req->req.channels[n_chans] =
 375                                                         req->channels[i];
 376                                 n_chans++;
 377                                 bands_used |= BIT(req->channels[i]->band);
 378                         }
 379
 380                         local->hw_scan_band++;
 381                 } while (!n_chans);
 382         }
 383
 384         local->hw_scan_req->req.n_channels = n_chans;
 385         ieee80211_prepare_scan_chandef(&chandef);
 386
 387         if (req->flags & NL80211_SCAN_FLAG_MIN_PREQ_CONTENT)
 388                 flags |= IEEE80211_PROBE_FLAG_MIN_CONTENT;
 389
 390         ielen = ieee80211_build_preq_ies(sdata,
 391                                          (u8 *)local->hw_scan_req->req.ie,
 392                                          local->hw_scan_ies_bufsize,
 393                                          &local->hw_scan_req->ies,
 394                                          req->ie, req->ie_len,
 395                                          bands_used, req->rates, &chandef,
 396                                          flags);
 397         local->hw_scan_req->req.ie_len = ielen;
 398         local->hw_scan_req->req.no_cck = req->no_cck;
 399         ether_addr_copy(local->hw_scan_req->req.mac_addr, req->mac_addr);
 400         ether_addr_copy(local->hw_scan_req->req.mac_addr_mask,
 401                         req->mac_addr_mask);
 402         ether_addr_copy(local->hw_scan_req->req.bssid, req->bssid);
 403
 404         return true;
 405 }
 406
 407 static void __ieee80211_scan_completed(struct ieee80211_hw *hw, bool aborted)
 408 {
 409         struct ieee80211_local *local = hw_to_local(hw);
 410         bool hw_scan = test_bit(SCAN_HW_SCANNING, &local->scanning);
 411         bool was_scanning = local->scanning;
 412         struct cfg80211_scan_request *scan_req;
 413         struct ieee80211_sub_if_data *scan_sdata;
 414         struct ieee80211_sub_if_data *sdata;
 415
 416         lockdep_assert_wiphy(local->hw.wiphy);
 417
 418         /*
 419          * It's ok to abort a not-yet-running scan (that
 420          * we have one at all will be verified by checking
 421          * local->scan_req next), but not to complete it
 422          * successfully.
 423          */
 424         if (WARN_ON(!local->scanning && !aborted))
 425                 aborted = true;
 426
 427         if (WARN_ON(!local->scan_req))
 428                 return;
 429
 430         scan_sdata = rcu_dereference_protected(local->scan_sdata,
 431                                                lockdep_is_held(&local->hw.wiphy->mtx));
 432
 433         if (hw_scan && !aborted &&
 434             !ieee80211_hw_check(&local->hw, SINGLE_SCAN_ON_ALL_BANDS) &&
 435             ieee80211_prep_hw_scan(scan_sdata)) {
 436                 int rc;
 437
 438                 rc = drv_hw_scan(local,
 439                         rcu_dereference_protected(local->scan_sdata,
 440                                                   lockdep_is_held(&local->hw.wiphy->mtx)),
 441                         local->hw_scan_req);
 442
 443                 if (rc == 0)
 444                         return;
 445
 446                 /* HW scan failed and is going to be reported as aborted,
 447                  * so clear old scan info.
 448                  */
 449                 memset(&local->scan_info, 0, sizeof(local->scan_info));
 450                 aborted = true;
 451         }
 452
 453         kfree(local->hw_scan_req);
 454         local->hw_scan_req = NULL;
 455
 456         scan_req = rcu_dereference_protected(local->scan_req,
 457                                              lockdep_is_held(&local->hw.wiphy->mtx));
 458
 459         RCU_INIT_POINTER(local->scan_req, NULL);
 460         RCU_INIT_POINTER(local->scan_sdata, NULL);
 461
 462         local->scanning = 0;
 463         local->scan_chandef.chan = NULL;
 464
 465         synchronize_rcu();
 466
 467         if (scan_req != local->int_scan_req) {
 468                 local->scan_info.aborted = aborted;
 469                 cfg80211_scan_done(scan_req, &local->scan_info);
 470         }
 471
 472         /* Set power back to normal operating levels. */
 473         ieee80211_hw_config(local, 0);
 474
 475         if (!hw_scan && was_scanning) {
 476                 ieee80211_configure_filter(local);
 477                 drv_sw_scan_complete(local, scan_sdata);
 478                 ieee80211_offchannel_return(local);
 479         }
 480
 481         ieee80211_recalc_idle(local);
 482
 483         ieee80211_mlme_notify_scan_completed(local);
 484         ieee80211_ibss_notify_scan_completed(local);
 485
 486         /* Requeue all the work that might have been ignored while
 487          * the scan was in progress; if there was none this will
 488          * just be a no-op for the particular interface.
 489          */
 490         list_for_each_entry_rcu(sdata, &local->interfaces, list) {
 491                 if (ieee80211_sdata_running(sdata))
 492                         wiphy_work_queue(sdata->local->hw.wiphy, &sdata->work);
 493         }
 494
 495         if (was_scanning)
 496                 ieee80211_start_next_roc(local);
 497 }
 498
 499 void ieee80211_scan_completed(struct ieee80211_hw *hw,
 500                               struct cfg80211_scan_info *info)
 501 {
 502         struct ieee80211_local *local = hw_to_local(hw);
 503
 504         trace_api_scan_completed(local, info->aborted);
 505
 506         set_bit(SCAN_COMPLETED, &local->scanning);
 507         if (info->aborted)
 508                 set_bit(SCAN_ABORTED, &local->scanning);
 509
 510         memcpy(&local->scan_info, info, sizeof(*info));
 511
 512         wiphy_delayed_work_queue(local->hw.wiphy, &local->scan_work, 0);
 513 }
 514 EXPORT_SYMBOL(ieee80211_scan_completed);
 515
 516 static int ieee80211_start_sw_scan(struct ieee80211_local *local,
 517                                    struct ieee80211_sub_if_data *sdata)
 518 {
 519         /* Software scan is not supported in multi-channel cases */
 520         if (local->use_chanctx)
 521                 return -EOPNOTSUPP;
 522
 523         /*
 524          * Hardware/driver doesn't support hw_scan, so use software
 525          * scanning instead. First send a nullfunc frame with power save
 526          * bit on so that AP will buffer the frames for us while we are not
 527          * listening, then send probe requests to each channel and wait for
 528          * the responses. After all channels are scanned, tune back to the
 529          * original channel and send a nullfunc frame with power save bit
 530          * off to trigger the AP to send us all the buffered frames.
 531          *
 532          * Note that while local->sw_scanning is true everything else but
 533          * nullfunc frames and probe requests will be dropped in
 534          * ieee80211_tx_h_check_assoc().
 535          */
 536         drv_sw_scan_start(local, sdata, local->scan_addr);
 537
 538         local->leave_oper_channel_time = jiffies;
 539         local->next_scan_state = SCAN_DECISION;
 540         local->scan_channel_idx = 0;
 541
 542         ieee80211_offchannel_stop_vifs(local);
 543
 544         /* ensure nullfunc is transmitted before leaving operating channel */
 545         ieee80211_flush_queues(local, NULL, false);
 546
 547         ieee80211_configure_filter(local);
 548
 549         /* We need to set power level at maximum rate for scanning. */
 550         ieee80211_hw_config(local, 0);
 551
 552         wiphy_delayed_work_queue(local->hw.wiphy, &local->scan_work, 0);
 553
 554         return 0;
 555 }
 556
 557 static bool __ieee80211_can_leave_ch(struct ieee80211_sub_if_data *sdata)
 558 {
 559         struct ieee80211_local *local = sdata->local;
 560         struct ieee80211_sub_if_data *sdata_iter;
 561
 562         lockdep_assert_wiphy(local->hw.wiphy);
 563
 564         if (!ieee80211_is_radar_required(local))
 565                 return true;
 566
 567         if (!regulatory_pre_cac_allowed(local->hw.wiphy))
 568                 return false;
 569
 570         list_for_each_entry(sdata_iter, &local->interfaces, list) {
 571                 if (sdata_iter->wdev.cac_started)
 572                         return false;
 573         }
 574
 575         return true;
 576 }
 577
 578 static bool ieee80211_can_scan(struct ieee80211_local *local,
 579                                struct ieee80211_sub_if_data *sdata)
 580 {
 581         if (!__ieee80211_can_leave_ch(sdata))
 582                 return false;
 583
 584         if (!list_empty(&local->roc_list))
 585                 return false;
 586
 587         if (sdata->vif.type == NL80211_IFTYPE_STATION &&
 588             sdata->u.mgd.flags & IEEE80211_STA_CONNECTION_POLL)
 589                 return false;
 590
 591         return true;
 592 }
 593
 594 void ieee80211_run_deferred_scan(struct ieee80211_local *local)
 595 {
 596         lockdep_assert_wiphy(local->hw.wiphy);
 597
 598         if (!local->scan_req || local->scanning)
 599                 return;
 600
 601         if (!ieee80211_can_scan(local,
 602                                 rcu_dereference_protected(
 603                                         local->scan_sdata,
 604                                         lockdep_is_held(&local->hw.wiphy->mtx))))
 605                 return;
 606
 607         wiphy_delayed_work_queue(local->hw.wiphy, &local->scan_work,
 608                                  round_jiffies_relative(0));
 609 }
 610
 611 static void ieee80211_send_scan_probe_req(struct ieee80211_sub_if_data *sdata,
 612                                           const u8 *src, const u8 *dst,
 613                                           const u8 *ssid, size_t ssid_len,
 614                                           const u8 *ie, size_t ie_len,
 615                                           u32 ratemask, u32 flags, u32 tx_flags,
 616                                           struct ieee80211_channel *channel)
 617 {
 618         struct sk_buff *skb;
 619
 620         skb = ieee80211_build_probe_req(sdata, src, dst, ratemask, channel,
 621                                         ssid, ssid_len,
 622                                         ie, ie_len, flags);
 623
 624         if (skb) {
 625                 if (flags & IEEE80211_PROBE_FLAG_RANDOM_SN) {
 626                         struct ieee80211_hdr *hdr = (void *)skb->data;
 627                         struct ieee80211_tx_info *info = IEEE80211_SKB_CB(skb);
 628                         u16 sn = get_random_u16();
 629
 630                         info->control.flags |= IEEE80211_TX_CTRL_NO_SEQNO;
 631                         hdr->seq_ctrl =
 632                                 cpu_to_le16(IEEE80211_SN_TO_SEQ(sn));
 633                 }
 634                 IEEE80211_SKB_CB(skb)->flags |= tx_flags;
 635                 ieee80211_tx_skb_tid_band(sdata, skb, 7, channel->band);
 636         }
 637 }
 638
 639 static void ieee80211_scan_state_send_probe(struct ieee80211_local *local,
 640                                             unsigned long *next_delay)
 641 {
 642         int i;
 643         struct ieee80211_sub_if_data *sdata;
 644         struct cfg80211_scan_request *scan_req;
 645         enum nl80211_band band = local->hw.conf.chandef.chan->band;
 646         u32 flags = 0, tx_flags;
 647
 648         scan_req = rcu_dereference_protected(local->scan_req,
 649                                              lockdep_is_held(&local->hw.wiphy->mtx));
 650
 651         tx_flags = IEEE80211_TX_INTFL_OFFCHAN_TX_OK;
 652         if (scan_req->no_cck)
 653                 tx_flags |= IEEE80211_TX_CTL_NO_CCK_RATE;
 654         if (scan_req->flags & NL80211_SCAN_FLAG_MIN_PREQ_CONTENT)
 655                 flags |= IEEE80211_PROBE_FLAG_MIN_CONTENT;
 656         if (scan_req->flags & NL80211_SCAN_FLAG_RANDOM_SN)
 657                 flags |= IEEE80211_PROBE_FLAG_RANDOM_SN;
 658
 659         sdata = rcu_dereference_protected(local->scan_sdata,
 660                                           lockdep_is_held(&local->hw.wiphy->mtx));
 661
 662         for (i = 0; i < scan_req->n_ssids; i++)
 663                 ieee80211_send_scan_probe_req(
 664                         sdata, local->scan_addr, scan_req->bssid,
 665                         scan_req->ssids[i].ssid, scan_req->ssids[i].ssid_len,
 666                         scan_req->ie, scan_req->ie_len,
 667                         scan_req->rates[band], flags,
 668                         tx_flags, local->hw.conf.chandef.chan);
 669
 670         /*
 671          * After sending probe requests, wait for probe responses
 672          * on the channel.
 673          */
 674         *next_delay = IEEE80211_CHANNEL_TIME;
 675         local->next_scan_state = SCAN_DECISION;
 676 }
 677
 678 static int __ieee80211_start_scan(struct ieee80211_sub_if_data *sdata,
 679                                   struct cfg80211_scan_request *req)
 680 {
 681         struct ieee80211_local *local = sdata->local;
 682         bool hw_scan = local->ops->hw_scan;
 683         int rc;
 684
 685         lockdep_assert_wiphy(local->hw.wiphy);
 686
 687         if (local->scan_req)
 688                 return -EBUSY;
 689
 690         /* For an MLO connection, if a link ID was specified, validate that it
 691          * is indeed active. If no link ID was specified, select one of the
 692          * active links.
 693          */
 694         if (ieee80211_vif_is_mld(&sdata->vif)) {
 695                 if (req->tsf_report_link_id >= 0) {
 696                         if (!(sdata->vif.active_links &
 697                               BIT(req->tsf_report_link_id)))
 698                                 return -EINVAL;
 699                 } else {
 700                         req->tsf_report_link_id =
 701                                 __ffs(sdata->vif.active_links);
 702                 }
 703         }
 704
 705         if (!__ieee80211_can_leave_ch(sdata))
 706                 return -EBUSY;
 707
 708         if (!ieee80211_can_scan(local, sdata)) {
 709                 /* wait for the work to finish/time out */
 710                 rcu_assign_pointer(local->scan_req, req);
 711                 rcu_assign_pointer(local->scan_sdata, sdata);
 712                 return 0;
 713         }
 714
 715  again:
 716         if (hw_scan) {
 717                 u8 *ies;
 718
 719                 local->hw_scan_ies_bufsize = local->scan_ies_len + req->ie_len;
 720
 721                 if (ieee80211_hw_check(&local->hw, SINGLE_SCAN_ON_ALL_BANDS)) {
 722                         int i, n_bands = 0;
 723                         u8 bands_counted = 0;
 724
 725                         for (i = 0; i < req->n_channels; i++) {
 726                                 if (bands_counted & BIT(req->channels[i]->band))
 727                                         continue;
 728                                 bands_counted |= BIT(req->channels[i]->band);
 729                                 n_bands++;
 730                         }
 731
 732                         local->hw_scan_ies_bufsize *= n_bands;
 733                 }
 734
 735                 local->hw_scan_req = kmalloc(
 736                                 sizeof(*local->hw_scan_req) +
 737                                 req->n_channels * sizeof(req->channels[0]) +
 738                                 local->hw_scan_ies_bufsize, GFP_KERNEL);
 739                 if (!local->hw_scan_req)
 740                         return -ENOMEM;
 741
 742                 local->hw_scan_req->req.ssids = req->ssids;
 743                 local->hw_scan_req->req.n_ssids = req->n_ssids;
 744                 ies = (u8 *)local->hw_scan_req +
 745                         sizeof(*local->hw_scan_req) +
 746                         req->n_channels * sizeof(req->channels[0]);
 747                 local->hw_scan_req->req.ie = ies;
 748                 local->hw_scan_req->req.flags = req->flags;
 749                 eth_broadcast_addr(local->hw_scan_req->req.bssid);
 750                 local->hw_scan_req->req.duration = req->duration;
 751                 local->hw_scan_req->req.duration_mandatory =
 752                         req->duration_mandatory;
 753                 local->hw_scan_req->req.tsf_report_link_id =
 754                         req->tsf_report_link_id;
 755
 756                 local->hw_scan_band = 0;
 757                 local->hw_scan_req->req.n_6ghz_params = req->n_6ghz_params;
 758                 local->hw_scan_req->req.scan_6ghz_params =
 759                         req->scan_6ghz_params;
 760                 local->hw_scan_req->req.scan_6ghz = req->scan_6ghz;
 761
 762                 /*
 763                  * After allocating local->hw_scan_req, we must
 764                  * go through until ieee80211_prep_hw_scan(), so
 765                  * anything that might be changed here and leave
 766                  * this function early must not go after this
 767                  * allocation.
 768                  */
 769         }
 770
 771         rcu_assign_pointer(local->scan_req, req);
 772         rcu_assign_pointer(local->scan_sdata, sdata);
 773
 774         if (req->flags & NL80211_SCAN_FLAG_RANDOM_ADDR)
 775                 get_random_mask_addr(local->scan_addr,
 776                                      req->mac_addr,
 777                                      req->mac_addr_mask);
 778         else
 779                 memcpy(local->scan_addr, sdata->vif.addr, ETH_ALEN);
 780
 781         if (hw_scan) {
 782                 __set_bit(SCAN_HW_SCANNING, &local->scanning);
 783         } else if ((req->n_channels == 1) &&
 784                    (req->channels[0] == local->_oper_chandef.chan)) {
 785                 /*
 786                  * If we are scanning only on the operating channel
 787                  * then we do not need to stop normal activities
 788                  */
 789                 unsigned long next_delay;
 790
 791                 __set_bit(SCAN_ONCHANNEL_SCANNING, &local->scanning);
 792
 793                 ieee80211_recalc_idle(local);
 794
 795                 /* Notify driver scan is starting, keep order of operations
 796                  * same as normal software scan, in case that matters. */
 797                 drv_sw_scan_start(local, sdata, local->scan_addr);
 798
 799                 ieee80211_configure_filter(local); /* accept probe-responses */
 800
 801                 /* We need to ensure power level is at max for scanning. */
 802                 ieee80211_hw_config(local, 0);
 803
 804                 if ((req->channels[0]->flags & (IEEE80211_CHAN_NO_IR |
 805                                                 IEEE80211_CHAN_RADAR)) ||
 806                     !req->n_ssids) {
 807                         next_delay = IEEE80211_PASSIVE_CHANNEL_TIME;
 808                         if (req->n_ssids)
 809                                 set_bit(SCAN_BEACON_WAIT, &local->scanning);
 810                 } else {
 811                         ieee80211_scan_state_send_probe(local, &next_delay);
 812                         next_delay = IEEE80211_CHANNEL_TIME;
 813                 }
 814
 815                 /* Now, just wait a bit and we are all done! */
 816                 wiphy_delayed_work_queue(local->hw.wiphy, &local->scan_work,
 817                                          next_delay);
 818                 return 0;
 819         } else {
 820                 /* Do normal software scan */
 821                 __set_bit(SCAN_SW_SCANNING, &local->scanning);
 822         }
 823
 824         ieee80211_recalc_idle(local);
 825
 826         if (hw_scan) {
 827                 WARN_ON(!ieee80211_prep_hw_scan(sdata));
 828                 rc = drv_hw_scan(local, sdata, local->hw_scan_req);
 829         } else {
 830                 rc = ieee80211_start_sw_scan(local, sdata);
 831         }
 832
 833         if (rc) {
 834                 kfree(local->hw_scan_req);
 835                 local->hw_scan_req = NULL;
 836                 local->scanning = 0;
 837
 838                 ieee80211_recalc_idle(local);
 839
 840                 local->scan_req = NULL;
 841                 RCU_INIT_POINTER(local->scan_sdata, NULL);
 842         }
 843
 844         if (hw_scan && rc == 1) {
 845                 /*
 846                  * we can't fall back to software for P2P-GO
 847                  * as it must update NoA etc.
 848                  */
 849                 if (ieee80211_vif_type_p2p(&sdata->vif) ==
 850                                 NL80211_IFTYPE_P2P_GO)
 851                         return -EOPNOTSUPP;
 852                 hw_scan = false;
 853                 goto again;
 854         }
 855
 856         return rc;
 857 }
 858
 859 static unsigned long
 860 ieee80211_scan_get_channel_time(struct ieee80211_channel *chan)
 861 {
 862         /*
 863          * TODO: channel switching also consumes quite some time,
 864          * add that delay as well to get a better estimation
 865          */
 866         if (chan->flags & (IEEE80211_CHAN_NO_IR | IEEE80211_CHAN_RADAR))
 867                 return IEEE80211_PASSIVE_CHANNEL_TIME;
 868         return IEEE80211_PROBE_DELAY + IEEE80211_CHANNEL_TIME;
 869 }
 870
 871 static void ieee80211_scan_state_decision(struct ieee80211_local *local,
 872                                           unsigned long *next_delay)
 873 {
 874         bool associated = false;
 875         bool tx_empty = true;
 876         bool bad_latency;
 877         struct ieee80211_sub_if_data *sdata;
 878         struct ieee80211_channel *next_chan;
 879         enum mac80211_scan_state next_scan_state;
 880         struct cfg80211_scan_request *scan_req;
 881
 882         lockdep_assert_wiphy(local->hw.wiphy);
 883
 884         /*
 885          * check if at least one STA interface is associated,
 886          * check if at least one STA interface has pending tx frames
 887          * and grab the lowest used beacon interval
 888          */
 889         list_for_each_entry(sdata, &local->interfaces, list) {
 890                 if (!ieee80211_sdata_running(sdata))
 891                         continue;
 892
 893                 if (sdata->vif.type == NL80211_IFTYPE_STATION) {
 894                         if (sdata->u.mgd.associated) {
 895                                 associated = true;
 896
 897                                 if (!qdisc_all_tx_empty(sdata->dev)) {
 898                                         tx_empty = false;
 899                                         break;
 900                                 }
 901                         }
 902                 }
 903         }
 904
 905         scan_req = rcu_dereference_protected(local->scan_req,
 906                                              lockdep_is_held(&local->hw.wiphy->mtx));
 907
 908         next_chan = scan_req->channels[local->scan_channel_idx];
 909
 910         /*
 911          * we're currently scanning a different channel, let's
 912          * see if we can scan another channel without interfering
 913          * with the current traffic situation.
 914          *
 915          * Keep good latency, do not stay off-channel more than 125 ms.
 916          */
 917
 918         bad_latency = time_after(jiffies +
 919                                  ieee80211_scan_get_channel_time(next_chan),
 920                                  local->leave_oper_channel_time + HZ / 8);
 921
 922         if (associated && !tx_empty) {
 923                 if (scan_req->flags & NL80211_SCAN_FLAG_LOW_PRIORITY)
 924                         next_scan_state = SCAN_ABORT;
 925                 else
 926                         next_scan_state = SCAN_SUSPEND;
 927         } else if (associated && bad_latency) {
 928                 next_scan_state = SCAN_SUSPEND;
 929         } else {
 930                 next_scan_state = SCAN_SET_CHANNEL;
 931         }
 932
 933         local->next_scan_state = next_scan_state;
 934
 935         *next_delay = 0;
 936 }
 937
 938 static void ieee80211_scan_state_set_channel(struct ieee80211_local *local,
 939                                              unsigned long *next_delay)
 940 {
 941         int skip;
 942         struct ieee80211_channel *chan;
 943         struct cfg80211_scan_request *scan_req;
 944
 945         scan_req = rcu_dereference_protected(local->scan_req,
 946                                              lockdep_is_held(&local->hw.wiphy->mtx));
 947
 948         skip = 0;
 949         chan = scan_req->channels[local->scan_channel_idx];
 950
 951         local->scan_chandef.chan = chan;
 952         local->scan_chandef.center_freq1 = chan->center_freq;
 953         local->scan_chandef.freq1_offset = chan->freq_offset;
 954         local->scan_chandef.center_freq2 = 0;
 955
 956         /* For scanning on the S1G band, detect the channel width according to
 957          * the channel being scanned.
 958          */
 959         if (chan->band == NL80211_BAND_S1GHZ) {
 960                 local->scan_chandef.width = ieee80211_s1g_channel_width(chan);
 961                 goto set_channel;
 962         }
 963
 964         /* If scanning on oper channel, use whatever channel-type
 965          * is currently in use.
 966          */
 967         if (chan == local->_oper_chandef.chan)
 968                 local->scan_chandef = local->_oper_chandef;
 969         else
 970                 local->scan_chandef.width = NL80211_CHAN_WIDTH_20_NOHT;
 971
 972 set_channel:
 973         if (ieee80211_hw_config(local, IEEE80211_CONF_CHANGE_CHANNEL))
 974                 skip = 1;
 975
 976         /* advance state machine to next channel/band */
 977         local->scan_channel_idx++;
 978
 979         if (skip) {
 980                 /* if we skip this channel return to the decision state */
 981                 local->next_scan_state = SCAN_DECISION;
 982                 return;
 983         }
 984
 985         /*
 986          * Probe delay is used to update the NAV, cf. 11.1.3.2.2
 987          * (which unfortunately doesn't say _why_ step a) is done,
 988          * but it waits for the probe delay or until a frame is
 989          * received - and the received frame would update the NAV).
 990          * For now, we do not support waiting until a frame is
 991          * received.
 992          *
 993          * In any case, it is not necessary for a passive scan.
 994          */
 995         if ((chan->flags & (IEEE80211_CHAN_NO_IR | IEEE80211_CHAN_RADAR)) ||
 996             !scan_req->n_ssids) {
 997                 *next_delay = IEEE80211_PASSIVE_CHANNEL_TIME;
 998                 local->next_scan_state = SCAN_DECISION;
 999                 if (scan_req->n_ssids)
1000                         set_bit(SCAN_BEACON_WAIT, &local->scanning);
1001                 return;
1002         }
1003
1004         /* active scan, send probes */
1005         *next_delay = IEEE80211_PROBE_DELAY;
1006         local->next_scan_state = SCAN_SEND_PROBE;
1007 }
1008
1009 static void ieee80211_scan_state_suspend(struct ieee80211_local *local,
1010                                          unsigned long *next_delay)
1011 {
1012         /* switch back to the operating channel */
1013         local->scan_chandef.chan = NULL;
1014         ieee80211_hw_config(local, IEEE80211_CONF_CHANGE_CHANNEL);
1015
1016         /* disable PS */
1017         ieee80211_offchannel_return(local);
1018
1019         *next_delay = HZ / 5;
1020         /* afterwards, resume scan & go to next channel */
1021         local->next_scan_state = SCAN_RESUME;
1022 }
1023
1024 static void ieee80211_scan_state_resume(struct ieee80211_local *local,
1025                                         unsigned long *next_delay)
1026 {
1027         ieee80211_offchannel_stop_vifs(local);
1028
1029         if (local->ops->flush) {
1030                 ieee80211_flush_queues(local, NULL, false);
1031                 *next_delay = 0;
1032         } else
1033                 *next_delay = HZ / 10;
1034
1035         /* remember when we left the operating channel */
1036         local->leave_oper_channel_time = jiffies;
1037
1038         /* advance to the next channel to be scanned */
1039         local->next_scan_state = SCAN_SET_CHANNEL;
1040 }
1041
1042 void ieee80211_scan_work(struct wiphy *wiphy, struct wiphy_work *work)
1043 {
1044         struct ieee80211_local *local =
1045                 container_of(work, struct ieee80211_local, scan_work.work);
1046         struct ieee80211_sub_if_data *sdata;
1047         struct cfg80211_scan_request *scan_req;
1048         unsigned long next_delay = 0;
1049         bool aborted;
1050
1051         lockdep_assert_wiphy(local->hw.wiphy);
1052
1053         if (!ieee80211_can_run_worker(local)) {
1054                 aborted = true;
1055                 goto out_complete;
1056         }
1057
1058         sdata = rcu_dereference_protected(local->scan_sdata,
1059                                           lockdep_is_held(&local->hw.wiphy->mtx));
1060         scan_req = rcu_dereference_protected(local->scan_req,
1061                                              lockdep_is_held(&local->hw.wiphy->mtx));
1062
1063         /* When scanning on-channel, the first-callback means completed. */
1064         if (test_bit(SCAN_ONCHANNEL_SCANNING, &local->scanning)) {
1065                 aborted = test_and_clear_bit(SCAN_ABORTED, &local->scanning);
1066                 goto out_complete;
1067         }
1068
1069         if (test_and_clear_bit(SCAN_COMPLETED, &local->scanning)) {
1070                 aborted = test_and_clear_bit(SCAN_ABORTED, &local->scanning);
1071                 goto out_complete;
1072         }
1073
1074         if (!sdata || !scan_req)
1075                 return;
1076
1077         if (!local->scanning) {
1078                 int rc;
1079
1080                 RCU_INIT_POINTER(local->scan_req, NULL);
1081                 RCU_INIT_POINTER(local->scan_sdata, NULL);
1082
1083                 rc = __ieee80211_start_scan(sdata, scan_req);
1084                 if (!rc)
1085                         return;
1086                 /* need to complete scan in cfg80211 */
1087                 rcu_assign_pointer(local->scan_req, scan_req);
1088                 aborted = true;
1089                 goto out_complete;
1090         }
1091
1092         clear_bit(SCAN_BEACON_WAIT, &local->scanning);
1093
1094         /*
1095          * as long as no delay is required advance immediately
1096          * without scheduling a new work
1097          */
1098         do {
1099                 if (!ieee80211_sdata_running(sdata)) {
1100                         aborted = true;
1101                         goto out_complete;
1102                 }
1103
1104                 if (test_and_clear_bit(SCAN_BEACON_DONE, &local->scanning) &&
1105                     local->next_scan_state == SCAN_DECISION)
1106                         local->next_scan_state = SCAN_SEND_PROBE;
1107
1108                 switch (local->next_scan_state) {
1109                 case SCAN_DECISION:
1110                         /* if no more bands/channels left, complete scan */
1111                         if (local->scan_channel_idx >= scan_req->n_channels) {
1112                                 aborted = false;
1113                                 goto out_complete;
1114                         }
1115                         ieee80211_scan_state_decision(local, &next_delay);
1116                         break;
1117                 case SCAN_SET_CHANNEL:
1118                         ieee80211_scan_state_set_channel(local, &next_delay);
1119                         break;
1120                 case SCAN_SEND_PROBE:
1121                         ieee80211_scan_state_send_probe(local, &next_delay);
1122                         break;
1123                 case SCAN_SUSPEND:
1124                         ieee80211_scan_state_suspend(local, &next_delay);
1125                         break;
1126                 case SCAN_RESUME:
1127                         ieee80211_scan_state_resume(local, &next_delay);
1128                         break;
1129                 case SCAN_ABORT:
1130                         aborted = true;
1131                         goto out_complete;
1132                 }
1133         } while (next_delay == 0);
1134
1135         wiphy_delayed_work_queue(local->hw.wiphy, &local->scan_work,
1136                                  next_delay);
1137         return;
1138
1139 out_complete:
1140         __ieee80211_scan_completed(&local->hw, aborted);
1141 }
1142
1143 int ieee80211_request_scan(struct ieee80211_sub_if_data *sdata,
1144                            struct cfg80211_scan_request *req)
1145 {
1146         lockdep_assert_wiphy(sdata->local->hw.wiphy);
1147
1148         return __ieee80211_start_scan(sdata, req);
1149 }
1150
1151 int ieee80211_request_ibss_scan(struct ieee80211_sub_if_data *sdata,
1152                                 const u8 *ssid, u8 ssid_len,
1153                                 struct ieee80211_channel **channels,
1154                                 unsigned int n_channels)
1155 {
1156         struct ieee80211_local *local = sdata->local;
1157         int ret = -EBUSY, i, n_ch = 0;
1158         enum nl80211_band band;
1159
1160         lockdep_assert_wiphy(local->hw.wiphy);
1161
1162         /* busy scanning */
1163         if (local->scan_req)
1164                 goto unlock;
1165
1166         /* fill internal scan request */
1167         if (!channels) {
1168                 int max_n;
1169
1170                 for (band = 0; band < NUM_NL80211_BANDS; band++) {
1171                         if (!local->hw.wiphy->bands[band] ||
1172                             band == NL80211_BAND_6GHZ)
1173                                 continue;
1174
1175                         max_n = local->hw.wiphy->bands[band]->n_channels;
1176                         for (i = 0; i < max_n; i++) {
1177                                 struct ieee80211_channel *tmp_ch =
1178                                     &local->hw.wiphy->bands[band]->channels[i];
1179
1180                                 if (tmp_ch->flags & (IEEE80211_CHAN_NO_IR |
1181                                                      IEEE80211_CHAN_DISABLED))
1182                                         continue;
1183
1184                                 local->int_scan_req->channels[n_ch] = tmp_ch;
1185                                 n_ch++;
1186                         }
1187                 }
1188
1189                 if (WARN_ON_ONCE(n_ch == 0))
1190                         goto unlock;
1191
1192                 local->int_scan_req->n_channels = n_ch;
1193         } else {
1194                 for (i = 0; i < n_channels; i++) {
1195                         if (channels[i]->flags & (IEEE80211_CHAN_NO_IR |
1196                                                   IEEE80211_CHAN_DISABLED))
1197                                 continue;
1198
1199                         local->int_scan_req->channels[n_ch] = channels[i];
1200                         n_ch++;
1201                 }
1202
1203                 if (WARN_ON_ONCE(n_ch == 0))
1204                         goto unlock;
1205
1206                 local->int_scan_req->n_channels = n_ch;
1207         }
1208
1209         local->int_scan_req->ssids = &local->scan_ssid;
1210         local->int_scan_req->n_ssids = 1;
1211         memcpy(local->int_scan_req->ssids[0].ssid, ssid, IEEE80211_MAX_SSID_LEN);
1212         local->int_scan_req->ssids[0].ssid_len = ssid_len;
1213
1214         ret = __ieee80211_start_scan(sdata, sdata->local->int_scan_req);
1215  unlock:
1216         return ret;
1217 }
1218
1219 void ieee80211_scan_cancel(struct ieee80211_local *local)
1220 {
1221         /* ensure a new scan cannot be queued */
1222         lockdep_assert_wiphy(local->hw.wiphy);
1223
1224         /*
1225          * We are canceling software scan, or deferred scan that was not
1226          * yet really started (see __ieee80211_start_scan ).
1227          *
1228          * Regarding hardware scan:
1229          * - we can not call  __ieee80211_scan_completed() as when
1230          *   SCAN_HW_SCANNING bit is set this function change
1231          *   local->hw_scan_req to operate on 5G band, what race with
1232          *   driver which can use local->hw_scan_req
1233          *
1234          * - we can not cancel scan_work since driver can schedule it
1235          *   by ieee80211_scan_completed(..., true) to finish scan
1236          *
1237          * Hence we only call the cancel_hw_scan() callback, but the low-level
1238          * driver is still responsible for calling ieee80211_scan_completed()
1239          * after the scan was completed/aborted.
1240          */
1241
1242         if (!local->scan_req)
1243                 return;
1244
1245         /*
1246          * We have a scan running and the driver already reported completion,
1247          * but the worker hasn't run yet or is stuck on the mutex - mark it as
1248          * cancelled.
1249          */
1250         if (test_bit(SCAN_HW_SCANNING, &local->scanning) &&
1251             test_bit(SCAN_COMPLETED, &local->scanning)) {
1252                 set_bit(SCAN_HW_CANCELLED, &local->scanning);
1253                 return;
1254         }
1255
1256         if (test_bit(SCAN_HW_SCANNING, &local->scanning)) {
1257                 /*
1258                  * Make sure that __ieee80211_scan_completed doesn't trigger a
1259                  * scan on another band.
1260                  */
1261                 set_bit(SCAN_HW_CANCELLED, &local->scanning);
1262                 if (local->ops->cancel_hw_scan)
1263                         drv_cancel_hw_scan(local,
1264                                 rcu_dereference_protected(local->scan_sdata,
1265                                                 lockdep_is_held(&local->hw.wiphy->mtx)));
1266                 return;
1267         }
1268
1269         wiphy_delayed_work_cancel(local->hw.wiphy, &local->scan_work);
1270         /* and clean up */
1271         memset(&local->scan_info, 0, sizeof(local->scan_info));
1272         __ieee80211_scan_completed(&local->hw, true);
1273 }
1274
1275 int __ieee80211_request_sched_scan_start(struct ieee80211_sub_if_data *sdata,
1276                                         struct cfg80211_sched_scan_request *req)
1277 {
1278         struct ieee80211_local *local = sdata->local;
1279         struct ieee80211_scan_ies sched_scan_ies = {};
1280         struct cfg80211_chan_def chandef;
1281         int ret, i, iebufsz, num_bands = 0;
1282         u32 rate_masks[NUM_NL80211_BANDS] = {};
1283         u8 bands_used = 0;
1284         u8 *ie;
1285         u32 flags = 0;
1286
1287         lockdep_assert_wiphy(local->hw.wiphy);
1288
1289         iebufsz = local->scan_ies_len + req->ie_len;
1290
1291         if (!local->ops->sched_scan_start)
1292                 return -EOPNOTSUPP;
1293
1294         for (i = 0; i < NUM_NL80211_BANDS; i++) {
1295                 if (local->hw.wiphy->bands[i]) {
1296                         bands_used |= BIT(i);
1297                         rate_masks[i] = (u32) -1;
1298                         num_bands++;
1299                 }
1300         }
1301
1302         if (req->flags & NL80211_SCAN_FLAG_MIN_PREQ_CONTENT)
1303                 flags |= IEEE80211_PROBE_FLAG_MIN_CONTENT;
1304
1305         ie = kcalloc(iebufsz, num_bands, GFP_KERNEL);
1306         if (!ie) {
1307                 ret = -ENOMEM;
1308                 goto out;
1309         }
1310
1311         ieee80211_prepare_scan_chandef(&chandef);
1312
1313         ieee80211_build_preq_ies(sdata, ie, num_bands * iebufsz,
1314                                  &sched_scan_ies, req->ie,
1315                                  req->ie_len, bands_used, rate_masks, &chandef,
1316                                  flags);
1317
1318         ret = drv_sched_scan_start(local, sdata, req, &sched_scan_ies);
1319         if (ret == 0) {
1320                 rcu_assign_pointer(local->sched_scan_sdata, sdata);
1321                 rcu_assign_pointer(local->sched_scan_req, req);
1322         }
1323
1324         kfree(ie);
1325
1326 out:
1327         if (ret) {
1328                 /* Clean in case of failure after HW restart or upon resume. */
1329                 RCU_INIT_POINTER(local->sched_scan_sdata, NULL);
1330                 RCU_INIT_POINTER(local->sched_scan_req, NULL);
1331         }
1332
1333         return ret;
1334 }
1335
1336 int ieee80211_request_sched_scan_start(struct ieee80211_sub_if_data *sdata,
1337                                        struct cfg80211_sched_scan_request *req)
1338 {
1339         struct ieee80211_local *local = sdata->local;
1340
1341         lockdep_assert_wiphy(local->hw.wiphy);
1342
1343         if (rcu_access_pointer(local->sched_scan_sdata))
1344                 return -EBUSY;
1345
1346         return __ieee80211_request_sched_scan_start(sdata, req);
1347 }
1348
1349 int ieee80211_request_sched_scan_stop(struct ieee80211_local *local)
1350 {
1351         struct ieee80211_sub_if_data *sched_scan_sdata;
1352         int ret = -ENOENT;
1353
1354         lockdep_assert_wiphy(local->hw.wiphy);
1355
1356         if (!local->ops->sched_scan_stop)
1357                 return -EOPNOTSUPP;
1358
1359         /* We don't want to restart sched scan anymore. */
1360         RCU_INIT_POINTER(local->sched_scan_req, NULL);
1361
1362         sched_scan_sdata = rcu_dereference_protected(local->sched_scan_sdata,
1363                                                 lockdep_is_held(&local->hw.wiphy->mtx));
1364         if (sched_scan_sdata) {
1365                 ret = drv_sched_scan_stop(local, sched_scan_sdata);
1366                 if (!ret)
1367                         RCU_INIT_POINTER(local->sched_scan_sdata, NULL);
1368         }
1369
1370         return ret;
1371 }
1372
1373 void ieee80211_sched_scan_results(struct ieee80211_hw *hw)
1374 {
1375         struct ieee80211_local *local = hw_to_local(hw);
1376
1377         trace_api_sched_scan_results(local);
1378
1379         cfg80211_sched_scan_results(hw->wiphy, 0);
1380 }
1381 EXPORT_SYMBOL(ieee80211_sched_scan_results);
1382
1383 void ieee80211_sched_scan_end(struct ieee80211_local *local)
1384 {
1385         lockdep_assert_wiphy(local->hw.wiphy);
1386
1387         if (!rcu_access_pointer(local->sched_scan_sdata))
1388                 return;
1389
1390         RCU_INIT_POINTER(local->sched_scan_sdata, NULL);
1391
1392         /* If sched scan was aborted by the driver. */
1393         RCU_INIT_POINTER(local->sched_scan_req, NULL);
1394
1395         cfg80211_sched_scan_stopped_locked(local->hw.wiphy, 0);
1396 }
1397
1398 void ieee80211_sched_scan_stopped_work(struct wiphy *wiphy,
1399                                        struct wiphy_work *work)
1400 {
1401         struct ieee80211_local *local =
1402                 container_of(work, struct ieee80211_local,
1403                              sched_scan_stopped_work);
1404
1405         ieee80211_sched_scan_end(local);
1406 }
1407
1408 void ieee80211_sched_scan_stopped(struct ieee80211_hw *hw)
1409 {
1410         struct ieee80211_local *local = hw_to_local(hw);
1411
1412         trace_api_sched_scan_stopped(local);
1413
1414         /*
1415          * this shouldn't really happen, so for simplicity
1416          * simply ignore it, and let mac80211 reconfigure
1417          * the sched scan later on.
1418          */
1419         if (local->in_reconfig)
1420                 return;
1421
1422         wiphy_work_queue(hw->wiphy, &local->sched_scan_stopped_work);
1423 }
1424 EXPORT_SYMBOL(ieee80211_sched_scan_stopped);