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) 2018-2020 Intel Corporation
  13  */
  14
  15 #include <linux/if_arp.h>
  16 #include <linux/etherdevice.h>
  17 #include <linux/rtnetlink.h>
  18 #include <net/sch_generic.h>
  19 #include <linux/slab.h>
  20 #include <linux/export.h>
  21 #include <linux/random.h>
  22 #include <net/mac80211.h>
  23
  24 #include "ieee80211_i.h"
  25 #include "driver-ops.h"
  26 #include "mesh.h"
  27
  28 #define IEEE80211_PROBE_DELAY (HZ / 33)
  29 #define IEEE80211_CHANNEL_TIME (HZ / 33)
  30 #define IEEE80211_PASSIVE_CHANNEL_TIME (HZ / 9)
  31
  32 void ieee80211_rx_bss_put(struct ieee80211_local *local,
  33                           struct ieee80211_bss *bss)
  34 {
  35         if (!bss)
  36                 return;
  37         cfg80211_put_bss(local->hw.wiphy,
  38                          container_of((void *)bss, struct cfg80211_bss, priv));
  39 }
  40
  41 static bool is_uapsd_supported(struct ieee802_11_elems *elems)
  42 {
  43         u8 qos_info;
  44
  45         if (elems->wmm_info && elems->wmm_info_len == 7
  46             && elems->wmm_info[5] == 1)
  47                 qos_info = elems->wmm_info[6];
  48         else if (elems->wmm_param && elems->wmm_param_len == 24
  49                  && elems->wmm_param[5] == 1)
  50                 qos_info = elems->wmm_param[6];
  51         else
  52                 /* no valid wmm information or parameter element found */
  53                 return false;
  54
  55         return qos_info & IEEE80211_WMM_IE_AP_QOSINFO_UAPSD;
  56 }
  57
  58 static void
  59 ieee80211_update_bss_from_elems(struct ieee80211_local *local,
  60                                 struct ieee80211_bss *bss,
  61                                 struct ieee802_11_elems *elems,
  62                                 struct ieee80211_rx_status *rx_status,
  63                                 bool beacon)
  64 {
  65         int clen, srlen;
  66
  67         if (beacon)
  68                 bss->device_ts_beacon = rx_status->device_timestamp;
  69         else
  70                 bss->device_ts_presp = rx_status->device_timestamp;
  71
  72         if (elems->parse_error) {
  73                 if (beacon)
  74                         bss->corrupt_data |= IEEE80211_BSS_CORRUPT_BEACON;
  75                 else
  76                         bss->corrupt_data |= IEEE80211_BSS_CORRUPT_PROBE_RESP;
  77         } else {
  78                 if (beacon)
  79                         bss->corrupt_data &= ~IEEE80211_BSS_CORRUPT_BEACON;
  80                 else
  81                         bss->corrupt_data &= ~IEEE80211_BSS_CORRUPT_PROBE_RESP;
  82         }
  83
  84         /* save the ERP value so that it is available at association time */
  85         if (elems->erp_info && (!elems->parse_error ||
  86                                 !(bss->valid_data & IEEE80211_BSS_VALID_ERP))) {
  87                 bss->erp_value = elems->erp_info[0];
  88                 bss->has_erp_value = true;
  89                 if (!elems->parse_error)
  90                         bss->valid_data |= IEEE80211_BSS_VALID_ERP;
  91         }
  92
  93         /* replace old supported rates if we get new values */
  94         if (!elems->parse_error ||
  95             !(bss->valid_data & IEEE80211_BSS_VALID_RATES)) {
  96                 srlen = 0;
  97                 if (elems->supp_rates) {
  98                         clen = IEEE80211_MAX_SUPP_RATES;
  99                         if (clen > elems->supp_rates_len)
 100                                 clen = elems->supp_rates_len;
 101                         memcpy(bss->supp_rates, elems->supp_rates, clen);
 102                         srlen += clen;
 103                 }
 104                 if (elems->ext_supp_rates) {
 105                         clen = IEEE80211_MAX_SUPP_RATES - srlen;
 106                         if (clen > elems->ext_supp_rates_len)
 107                                 clen = elems->ext_supp_rates_len;
 108                         memcpy(bss->supp_rates + srlen, elems->ext_supp_rates,
 109                                clen);
 110                         srlen += clen;
 111                 }
 112                 if (srlen) {
 113                         bss->supp_rates_len = srlen;
 114                         if (!elems->parse_error)
 115                                 bss->valid_data |= IEEE80211_BSS_VALID_RATES;
 116                 }
 117         }
 118
 119         if (!elems->parse_error ||
 120             !(bss->valid_data & IEEE80211_BSS_VALID_WMM)) {
 121                 bss->wmm_used = elems->wmm_param || elems->wmm_info;
 122                 bss->uapsd_supported = is_uapsd_supported(elems);
 123                 if (!elems->parse_error)
 124                         bss->valid_data |= IEEE80211_BSS_VALID_WMM;
 125         }
 126
 127         if (beacon) {
 128                 struct ieee80211_supported_band *sband =
 129                         local->hw.wiphy->bands[rx_status->band];
 130                 if (!(rx_status->encoding == RX_ENC_HT) &&
 131                     !(rx_status->encoding == RX_ENC_VHT))
 132                         bss->beacon_rate =
 133                                 &sband->bitrates[rx_status->rate_idx];
 134         }
 135
 136         if (elems->vht_cap_elem)
 137                 bss->vht_cap_info =
 138                         le32_to_cpu(elems->vht_cap_elem->vht_cap_info);
 139         else
 140                 bss->vht_cap_info = 0;
 141 }
 142
 143 struct ieee80211_bss *
 144 ieee80211_bss_info_update(struct ieee80211_local *local,
 145                           struct ieee80211_rx_status *rx_status,
 146                           struct ieee80211_mgmt *mgmt, size_t len,
 147                           struct ieee80211_channel *channel)
 148 {
 149         bool beacon = ieee80211_is_beacon(mgmt->frame_control) ||
 150                       ieee80211_is_s1g_beacon(mgmt->frame_control);
 151         struct cfg80211_bss *cbss, *non_tx_cbss;
 152         struct ieee80211_bss *bss, *non_tx_bss;
 153         struct cfg80211_inform_bss bss_meta = {
 154                 .boottime_ns = rx_status->boottime_ns,
 155         };
 156         bool signal_valid;
 157         struct ieee80211_sub_if_data *scan_sdata;
 158         struct ieee802_11_elems elems;
 159         size_t baselen;
 160         u8 *elements;
 161
 162         if (rx_status->flag & RX_FLAG_NO_SIGNAL_VAL)
 163                 bss_meta.signal = 0; /* invalid signal indication */
 164         else if (ieee80211_hw_check(&local->hw, SIGNAL_DBM))
 165                 bss_meta.signal = rx_status->signal * 100;
 166         else if (ieee80211_hw_check(&local->hw, SIGNAL_UNSPEC))
 167                 bss_meta.signal = (rx_status->signal * 100) / local->hw.max_signal;
 168
 169         bss_meta.scan_width = NL80211_BSS_CHAN_WIDTH_20;
 170         if (rx_status->bw == RATE_INFO_BW_5)
 171                 bss_meta.scan_width = NL80211_BSS_CHAN_WIDTH_5;
 172         else if (rx_status->bw == RATE_INFO_BW_10)
 173                 bss_meta.scan_width = NL80211_BSS_CHAN_WIDTH_10;
 174
 175         bss_meta.chan = channel;
 176
 177         rcu_read_lock();
 178         scan_sdata = rcu_dereference(local->scan_sdata);
 179         if (scan_sdata && scan_sdata->vif.type == NL80211_IFTYPE_STATION &&
 180             scan_sdata->vif.bss_conf.assoc &&
 181             ieee80211_have_rx_timestamp(rx_status)) {
 182                 bss_meta.parent_tsf =
 183                         ieee80211_calculate_rx_timestamp(local, rx_status,
 184                                                          len + FCS_LEN, 24);
 185                 ether_addr_copy(bss_meta.parent_bssid,
 186                                 scan_sdata->vif.bss_conf.bssid);
 187         }
 188         rcu_read_unlock();
 189
 190         cbss = cfg80211_inform_bss_frame_data(local->hw.wiphy, &bss_meta,
 191                                               mgmt, len, GFP_ATOMIC);
 192         if (!cbss)
 193                 return NULL;
 194
 195         if (ieee80211_is_probe_resp(mgmt->frame_control)) {
 196                 elements = mgmt->u.probe_resp.variable;
 197                 baselen = offsetof(struct ieee80211_mgmt,
 198                                    u.probe_resp.variable);
 199         } else if (ieee80211_is_s1g_beacon(mgmt->frame_control)) {
 200                 struct ieee80211_ext *ext = (void *) mgmt;
 201
 202                 baselen = offsetof(struct ieee80211_ext, u.s1g_beacon.variable);
 203                 elements = ext->u.s1g_beacon.variable;
 204         } else {
 205                 baselen = offsetof(struct ieee80211_mgmt, u.beacon.variable);
 206                 elements = mgmt->u.beacon.variable;
 207         }
 208
 209         if (baselen > len)
 210                 return NULL;
 211
 212         ieee802_11_parse_elems(elements, len - baselen, false, &elems,
 213                                mgmt->bssid, cbss->bssid);
 214
 215         /* In case the signal is invalid update the status */
 216         signal_valid = channel == cbss->channel;
 217         if (!signal_valid)
 218                 rx_status->flag |= RX_FLAG_NO_SIGNAL_VAL;
 219
 220         bss = (void *)cbss->priv;
 221         ieee80211_update_bss_from_elems(local, bss, &elems, rx_status, beacon);
 222
 223         list_for_each_entry(non_tx_cbss, &cbss->nontrans_list, nontrans_list) {
 224                 non_tx_bss = (void *)non_tx_cbss->priv;
 225
 226                 ieee80211_update_bss_from_elems(local, non_tx_bss, &elems,
 227                                                 rx_status, beacon);
 228         }
 229
 230         kfree(elems.nontx_profile);
 231
 232         return bss;
 233 }
 234
 235 static bool ieee80211_scan_accept_presp(struct ieee80211_sub_if_data *sdata,
 236                                         u32 scan_flags, const u8 *da)
 237 {
 238         if (!sdata)
 239                 return false;
 240         /* accept broadcast for OCE */
 241         if (scan_flags & NL80211_SCAN_FLAG_ACCEPT_BCAST_PROBE_RESP &&
 242             is_broadcast_ether_addr(da))
 243                 return true;
 244         if (scan_flags & NL80211_SCAN_FLAG_RANDOM_ADDR)
 245                 return true;
 246         return ether_addr_equal(da, sdata->vif.addr);
 247 }
 248
 249 void ieee80211_scan_rx(struct ieee80211_local *local, struct sk_buff *skb)
 250 {
 251         struct ieee80211_rx_status *rx_status = IEEE80211_SKB_RXCB(skb);
 252         struct ieee80211_sub_if_data *sdata1, *sdata2;
 253         struct ieee80211_mgmt *mgmt = (void *)skb->data;
 254         struct ieee80211_bss *bss;
 255         struct ieee80211_channel *channel;
 256         size_t min_hdr_len = offsetof(struct ieee80211_mgmt,
 257                                       u.probe_resp.variable);
 258
 259         if (!ieee80211_is_probe_resp(mgmt->frame_control) &&
 260             !ieee80211_is_beacon(mgmt->frame_control) &&
 261             !ieee80211_is_s1g_beacon(mgmt->frame_control))
 262                 return;
 263
 264         if (ieee80211_is_s1g_beacon(mgmt->frame_control)) {
 265                 if (ieee80211_is_s1g_short_beacon(mgmt->frame_control))
 266                         min_hdr_len = offsetof(struct ieee80211_ext,
 267                                                u.s1g_short_beacon.variable);
 268                 else
 269                         min_hdr_len = offsetof(struct ieee80211_ext,
 270                                                u.s1g_beacon);
 271         }
 272
 273         if (skb->len < min_hdr_len)
 274                 return;
 275
 276         sdata1 = rcu_dereference(local->scan_sdata);
 277         sdata2 = rcu_dereference(local->sched_scan_sdata);
 278
 279         if (likely(!sdata1 && !sdata2))
 280                 return;
 281
 282         if (test_and_clear_bit(SCAN_BEACON_WAIT, &local->scanning)) {
 283                 /*
 284                  * we were passive scanning because of radar/no-IR, but
 285                  * the beacon/proberesp rx gives us an opportunity to upgrade
 286                  * to active scan
 287                  */
 288                  set_bit(SCAN_BEACON_DONE, &local->scanning);
 289                  ieee80211_queue_delayed_work(&local->hw, &local->scan_work, 0);
 290         }
 291
 292         if (ieee80211_is_probe_resp(mgmt->frame_control)) {
 293                 struct cfg80211_scan_request *scan_req;
 294                 struct cfg80211_sched_scan_request *sched_scan_req;
 295                 u32 scan_req_flags = 0, sched_scan_req_flags = 0;
 296
 297                 scan_req = rcu_dereference(local->scan_req);
 298                 sched_scan_req = rcu_dereference(local->sched_scan_req);
 299
 300                 if (scan_req)
 301                         scan_req_flags = scan_req->flags;
 302
 303                 if (sched_scan_req)
 304                         sched_scan_req_flags = sched_scan_req->flags;
 305
 306                 /* ignore ProbeResp to foreign address or non-bcast (OCE)
 307                  * unless scanning with randomised address
 308                  */
 309                 if (!ieee80211_scan_accept_presp(sdata1, scan_req_flags,
 310                                                  mgmt->da) &&
 311                     !ieee80211_scan_accept_presp(sdata2, sched_scan_req_flags,
 312                                                  mgmt->da))
 313                         return;
 314         }
 315
 316         channel = ieee80211_get_channel_khz(local->hw.wiphy,
 317                                         ieee80211_rx_status_to_khz(rx_status));
 318
 319         if (!channel || channel->flags & IEEE80211_CHAN_DISABLED)
 320                 return;
 321
 322         bss = ieee80211_bss_info_update(local, rx_status,
 323                                         mgmt, skb->len,
 324                                         channel);
 325         if (bss)
 326                 ieee80211_rx_bss_put(local, bss);
 327 }
 328
 329 static void
 330 ieee80211_prepare_scan_chandef(struct cfg80211_chan_def *chandef,
 331                                enum nl80211_bss_scan_width scan_width)
 332 {
 333         memset(chandef, 0, sizeof(*chandef));
 334         switch (scan_width) {
 335         case NL80211_BSS_CHAN_WIDTH_5:
 336                 chandef->width = NL80211_CHAN_WIDTH_5;
 337                 break;
 338         case NL80211_BSS_CHAN_WIDTH_10:
 339                 chandef->width = NL80211_CHAN_WIDTH_10;
 340                 break;
 341         default:
 342                 chandef->width = NL80211_CHAN_WIDTH_20_NOHT;
 343                 break;
 344         }
 345 }
 346
 347 /* return false if no more work */
 348 static bool ieee80211_prep_hw_scan(struct ieee80211_sub_if_data *sdata)
 349 {
 350         struct ieee80211_local *local = sdata->local;
 351         struct cfg80211_scan_request *req;
 352         struct cfg80211_chan_def chandef;
 353         u8 bands_used = 0;
 354         int i, ielen, n_chans;
 355         u32 flags = 0;
 356
 357         req = rcu_dereference_protected(local->scan_req,
 358                                         lockdep_is_held(&local->mtx));
 359
 360         if (test_bit(SCAN_HW_CANCELLED, &local->scanning))
 361                 return false;
 362
 363         if (ieee80211_hw_check(&local->hw, SINGLE_SCAN_ON_ALL_BANDS)) {
 364                 for (i = 0; i < req->n_channels; i++) {
 365                         local->hw_scan_req->req.channels[i] = req->channels[i];
 366                         bands_used |= BIT(req->channels[i]->band);
 367                 }
 368
 369                 n_chans = req->n_channels;
 370         } else {
 371                 do {
 372                         if (local->hw_scan_band == NUM_NL80211_BANDS)
 373                                 return false;
 374
 375                         n_chans = 0;
 376
 377                         for (i = 0; i < req->n_channels; i++) {
 378                                 if (req->channels[i]->band !=
 379                                     local->hw_scan_band)
 380                                         continue;
 381                                 local->hw_scan_req->req.channels[n_chans] =
 382                                                         req->channels[i];
 383                                 n_chans++;
 384                                 bands_used |= BIT(req->channels[i]->band);
 385                         }
 386
 387                         local->hw_scan_band++;
 388                 } while (!n_chans);
 389         }
 390
 391         local->hw_scan_req->req.n_channels = n_chans;
 392         ieee80211_prepare_scan_chandef(&chandef, req->scan_width);
 393
 394         if (req->flags & NL80211_SCAN_FLAG_MIN_PREQ_CONTENT)
 395                 flags |= IEEE80211_PROBE_FLAG_MIN_CONTENT;
 396
 397         ielen = ieee80211_build_preq_ies(sdata,
 398                                          (u8 *)local->hw_scan_req->req.ie,
 399                                          local->hw_scan_ies_bufsize,
 400                                          &local->hw_scan_req->ies,
 401                                          req->ie, req->ie_len,
 402                                          bands_used, req->rates, &chandef,
 403                                          flags);
 404         local->hw_scan_req->req.ie_len = ielen;
 405         local->hw_scan_req->req.no_cck = req->no_cck;
 406         ether_addr_copy(local->hw_scan_req->req.mac_addr, req->mac_addr);
 407         ether_addr_copy(local->hw_scan_req->req.mac_addr_mask,
 408                         req->mac_addr_mask);
 409         ether_addr_copy(local->hw_scan_req->req.bssid, req->bssid);
 410
 411         return true;
 412 }
 413
 414 static void __ieee80211_scan_completed(struct ieee80211_hw *hw, bool aborted)
 415 {
 416         struct ieee80211_local *local = hw_to_local(hw);
 417         bool hw_scan = test_bit(SCAN_HW_SCANNING, &local->scanning);
 418         bool was_scanning = local->scanning;
 419         struct cfg80211_scan_request *scan_req;
 420         struct ieee80211_sub_if_data *scan_sdata;
 421         struct ieee80211_sub_if_data *sdata;
 422
 423         lockdep_assert_held(&local->mtx);
 424
 425         /*
 426          * It's ok to abort a not-yet-running scan (that
 427          * we have one at all will be verified by checking
 428          * local->scan_req next), but not to complete it
 429          * successfully.
 430          */
 431         if (WARN_ON(!local->scanning && !aborted))
 432                 aborted = true;
 433
 434         if (WARN_ON(!local->scan_req))
 435                 return;
 436
 437         scan_sdata = rcu_dereference_protected(local->scan_sdata,
 438                                                lockdep_is_held(&local->mtx));
 439
 440         if (hw_scan && !aborted &&
 441             !ieee80211_hw_check(&local->hw, SINGLE_SCAN_ON_ALL_BANDS) &&
 442             ieee80211_prep_hw_scan(scan_sdata)) {
 443                 int rc;
 444
 445                 rc = drv_hw_scan(local,
 446                         rcu_dereference_protected(local->scan_sdata,
 447                                                   lockdep_is_held(&local->mtx)),
 448                         local->hw_scan_req);
 449
 450                 if (rc == 0)
 451                         return;
 452
 453                 /* HW scan failed and is going to be reported as aborted,
 454                  * so clear old scan info.
 455                  */
 456                 memset(&local->scan_info, 0, sizeof(local->scan_info));
 457                 aborted = true;
 458         }
 459
 460         kfree(local->hw_scan_req);
 461         local->hw_scan_req = NULL;
 462
 463         scan_req = rcu_dereference_protected(local->scan_req,
 464                                              lockdep_is_held(&local->mtx));
 465
 466         RCU_INIT_POINTER(local->scan_req, NULL);
 467         RCU_INIT_POINTER(local->scan_sdata, NULL);
 468
 469         local->scanning = 0;
 470         local->scan_chandef.chan = NULL;
 471
 472         synchronize_rcu();
 473
 474         if (scan_req != local->int_scan_req) {
 475                 local->scan_info.aborted = aborted;
 476                 cfg80211_scan_done(scan_req, &local->scan_info);
 477         }
 478
 479         /* Set power back to normal operating levels. */
 480         ieee80211_hw_config(local, 0);
 481
 482         if (!hw_scan) {
 483                 ieee80211_configure_filter(local);
 484                 drv_sw_scan_complete(local, scan_sdata);
 485                 ieee80211_offchannel_return(local);
 486         }
 487
 488         ieee80211_recalc_idle(local);
 489
 490         ieee80211_mlme_notify_scan_completed(local);
 491         ieee80211_ibss_notify_scan_completed(local);
 492
 493         /* Requeue all the work that might have been ignored while
 494          * the scan was in progress; if there was none this will
 495          * just be a no-op for the particular interface.
 496          */
 497         list_for_each_entry_rcu(sdata, &local->interfaces, list) {
 498                 if (ieee80211_sdata_running(sdata))
 499                         ieee80211_queue_work(&sdata->local->hw, &sdata->work);
 500         }
 501
 502         if (was_scanning)
 503                 ieee80211_start_next_roc(local);
 504 }
 505
 506 void ieee80211_scan_completed(struct ieee80211_hw *hw,
 507                               struct cfg80211_scan_info *info)
 508 {
 509         struct ieee80211_local *local = hw_to_local(hw);
 510
 511         trace_api_scan_completed(local, info->aborted);
 512
 513         set_bit(SCAN_COMPLETED, &local->scanning);
 514         if (info->aborted)
 515                 set_bit(SCAN_ABORTED, &local->scanning);
 516
 517         memcpy(&local->scan_info, info, sizeof(*info));
 518
 519         ieee80211_queue_delayed_work(&local->hw, &local->scan_work, 0);
 520 }
 521 EXPORT_SYMBOL(ieee80211_scan_completed);
 522
 523 static int ieee80211_start_sw_scan(struct ieee80211_local *local,
 524                                    struct ieee80211_sub_if_data *sdata)
 525 {
 526         /* Software scan is not supported in multi-channel cases */
 527         if (local->use_chanctx)
 528                 return -EOPNOTSUPP;
 529
 530         /*
 531          * Hardware/driver doesn't support hw_scan, so use software
 532          * scanning instead. First send a nullfunc frame with power save
 533          * bit on so that AP will buffer the frames for us while we are not
 534          * listening, then send probe requests to each channel and wait for
 535          * the responses. After all channels are scanned, tune back to the
 536          * original channel and send a nullfunc frame with power save bit
 537          * off to trigger the AP to send us all the buffered frames.
 538          *
 539          * Note that while local->sw_scanning is true everything else but
 540          * nullfunc frames and probe requests will be dropped in
 541          * ieee80211_tx_h_check_assoc().
 542          */
 543         drv_sw_scan_start(local, sdata, local->scan_addr);
 544
 545         local->leave_oper_channel_time = jiffies;
 546         local->next_scan_state = SCAN_DECISION;
 547         local->scan_channel_idx = 0;
 548
 549         ieee80211_offchannel_stop_vifs(local);
 550
 551         /* ensure nullfunc is transmitted before leaving operating channel */
 552         ieee80211_flush_queues(local, NULL, false);
 553
 554         ieee80211_configure_filter(local);
 555
 556         /* We need to set power level at maximum rate for scanning. */
 557         ieee80211_hw_config(local, 0);
 558
 559         ieee80211_queue_delayed_work(&local->hw,
 560                                      &local->scan_work, 0);
 561
 562         return 0;
 563 }
 564
 565 static bool __ieee80211_can_leave_ch(struct ieee80211_sub_if_data *sdata)
 566 {
 567         struct ieee80211_local *local = sdata->local;
 568         struct ieee80211_sub_if_data *sdata_iter;
 569
 570         if (!ieee80211_is_radar_required(local))
 571                 return true;
 572
 573         if (!regulatory_pre_cac_allowed(local->hw.wiphy))
 574                 return false;
 575
 576         mutex_lock(&local->iflist_mtx);
 577         list_for_each_entry(sdata_iter, &local->interfaces, list) {
 578                 if (sdata_iter->wdev.cac_started) {
 579                         mutex_unlock(&local->iflist_mtx);
 580                         return false;
 581                 }
 582         }
 583         mutex_unlock(&local->iflist_mtx);
 584
 585         return true;
 586 }
 587
 588 static bool ieee80211_can_scan(struct ieee80211_local *local,
 589                                struct ieee80211_sub_if_data *sdata)
 590 {
 591         if (!__ieee80211_can_leave_ch(sdata))
 592                 return false;
 593
 594         if (!list_empty(&local->roc_list))
 595                 return false;
 596
 597         if (sdata->vif.type == NL80211_IFTYPE_STATION &&
 598             sdata->u.mgd.flags & IEEE80211_STA_CONNECTION_POLL)
 599                 return false;
 600
 601         return true;
 602 }
 603
 604 void ieee80211_run_deferred_scan(struct ieee80211_local *local)
 605 {
 606         lockdep_assert_held(&local->mtx);
 607
 608         if (!local->scan_req || local->scanning)
 609                 return;
 610
 611         if (!ieee80211_can_scan(local,
 612                                 rcu_dereference_protected(
 613                                         local->scan_sdata,
 614                                         lockdep_is_held(&local->mtx))))
 615                 return;
 616
 617         ieee80211_queue_delayed_work(&local->hw, &local->scan_work,
 618                                      round_jiffies_relative(0));
 619 }
 620
 621 static void ieee80211_send_scan_probe_req(struct ieee80211_sub_if_data *sdata,
 622                                           const u8 *src, const u8 *dst,
 623                                           const u8 *ssid, size_t ssid_len,
 624                                           const u8 *ie, size_t ie_len,
 625                                           u32 ratemask, u32 flags, u32 tx_flags,
 626                                           struct ieee80211_channel *channel)
 627 {
 628         struct sk_buff *skb;
 629
 630         skb = ieee80211_build_probe_req(sdata, src, dst, ratemask, channel,
 631                                         ssid, ssid_len,
 632                                         ie, ie_len, flags);
 633
 634         if (skb) {
 635                 if (flags & IEEE80211_PROBE_FLAG_RANDOM_SN) {
 636                         struct ieee80211_hdr *hdr = (void *)skb->data;
 637                         struct ieee80211_tx_info *info = IEEE80211_SKB_CB(skb);
 638                         u16 sn = get_random_u32();
 639
 640                         info->control.flags |= IEEE80211_TX_CTRL_NO_SEQNO;
 641                         hdr->seq_ctrl =
 642                                 cpu_to_le16(IEEE80211_SN_TO_SEQ(sn));
 643                 }
 644                 IEEE80211_SKB_CB(skb)->flags |= tx_flags;
 645                 ieee80211_tx_skb_tid_band(sdata, skb, 7, channel->band);
 646         }
 647 }
 648
 649 static void ieee80211_scan_state_send_probe(struct ieee80211_local *local,
 650                                             unsigned long *next_delay)
 651 {
 652         int i;
 653         struct ieee80211_sub_if_data *sdata;
 654         struct cfg80211_scan_request *scan_req;
 655         enum nl80211_band band = local->hw.conf.chandef.chan->band;
 656         u32 flags = 0, tx_flags;
 657
 658         scan_req = rcu_dereference_protected(local->scan_req,
 659                                              lockdep_is_held(&local->mtx));
 660
 661         tx_flags = IEEE80211_TX_INTFL_OFFCHAN_TX_OK;
 662         if (scan_req->no_cck)
 663                 tx_flags |= IEEE80211_TX_CTL_NO_CCK_RATE;
 664         if (scan_req->flags & NL80211_SCAN_FLAG_MIN_PREQ_CONTENT)
 665                 flags |= IEEE80211_PROBE_FLAG_MIN_CONTENT;
 666         if (scan_req->flags & NL80211_SCAN_FLAG_RANDOM_SN)
 667                 flags |= IEEE80211_PROBE_FLAG_RANDOM_SN;
 668
 669         sdata = rcu_dereference_protected(local->scan_sdata,
 670                                           lockdep_is_held(&local->mtx));
 671
 672         for (i = 0; i < scan_req->n_ssids; i++)
 673                 ieee80211_send_scan_probe_req(
 674                         sdata, local->scan_addr, scan_req->bssid,
 675                         scan_req->ssids[i].ssid, scan_req->ssids[i].ssid_len,
 676                         scan_req->ie, scan_req->ie_len,
 677                         scan_req->rates[band], flags,
 678                         tx_flags, local->hw.conf.chandef.chan);
 679
 680         /*
 681          * After sending probe requests, wait for probe responses
 682          * on the channel.
 683          */
 684         *next_delay = IEEE80211_CHANNEL_TIME;
 685         local->next_scan_state = SCAN_DECISION;
 686 }
 687
 688 static int __ieee80211_start_scan(struct ieee80211_sub_if_data *sdata,
 689                                   struct cfg80211_scan_request *req)
 690 {
 691         struct ieee80211_local *local = sdata->local;
 692         bool hw_scan = local->ops->hw_scan;
 693         int rc;
 694
 695         lockdep_assert_held(&local->mtx);
 696
 697         if (local->scan_req)
 698                 return -EBUSY;
 699
 700         if (!__ieee80211_can_leave_ch(sdata))
 701                 return -EBUSY;
 702
 703         if (!ieee80211_can_scan(local, sdata)) {
 704                 /* wait for the work to finish/time out */
 705                 rcu_assign_pointer(local->scan_req, req);
 706                 rcu_assign_pointer(local->scan_sdata, sdata);
 707                 return 0;
 708         }
 709
 710  again:
 711         if (hw_scan) {
 712                 u8 *ies;
 713
 714                 local->hw_scan_ies_bufsize = local->scan_ies_len + req->ie_len;
 715
 716                 if (ieee80211_hw_check(&local->hw, SINGLE_SCAN_ON_ALL_BANDS)) {
 717                         int i, n_bands = 0;
 718                         u8 bands_counted = 0;
 719
 720                         for (i = 0; i < req->n_channels; i++) {
 721                                 if (bands_counted & BIT(req->channels[i]->band))
 722                                         continue;
 723                                 bands_counted |= BIT(req->channels[i]->band);
 724                                 n_bands++;
 725                         }
 726
 727                         local->hw_scan_ies_bufsize *= n_bands;
 728                 }
 729
 730                 local->hw_scan_req = kmalloc(
 731                                 sizeof(*local->hw_scan_req) +
 732                                 req->n_channels * sizeof(req->channels[0]) +
 733                                 local->hw_scan_ies_bufsize, GFP_KERNEL);
 734                 if (!local->hw_scan_req)
 735                         return -ENOMEM;
 736
 737                 local->hw_scan_req->req.ssids = req->ssids;
 738                 local->hw_scan_req->req.n_ssids = req->n_ssids;
 739                 ies = (u8 *)local->hw_scan_req +
 740                         sizeof(*local->hw_scan_req) +
 741                         req->n_channels * sizeof(req->channels[0]);
 742                 local->hw_scan_req->req.ie = ies;
 743                 local->hw_scan_req->req.flags = req->flags;
 744                 eth_broadcast_addr(local->hw_scan_req->req.bssid);
 745                 local->hw_scan_req->req.duration = req->duration;
 746                 local->hw_scan_req->req.duration_mandatory =
 747                         req->duration_mandatory;
 748
 749                 local->hw_scan_band = 0;
 750                 local->hw_scan_req->req.n_6ghz_params = req->n_6ghz_params;
 751                 local->hw_scan_req->req.scan_6ghz_params =
 752                         req->scan_6ghz_params;
 753                 local->hw_scan_req->req.scan_6ghz = req->scan_6ghz;
 754
 755                 /*
 756                  * After allocating local->hw_scan_req, we must
 757                  * go through until ieee80211_prep_hw_scan(), so
 758                  * anything that might be changed here and leave
 759                  * this function early must not go after this
 760                  * allocation.
 761                  */
 762         }
 763
 764         rcu_assign_pointer(local->scan_req, req);
 765         rcu_assign_pointer(local->scan_sdata, sdata);
 766
 767         if (req->flags & NL80211_SCAN_FLAG_RANDOM_ADDR)
 768                 get_random_mask_addr(local->scan_addr,
 769                                      req->mac_addr,
 770                                      req->mac_addr_mask);
 771         else
 772                 memcpy(local->scan_addr, sdata->vif.addr, ETH_ALEN);
 773
 774         if (hw_scan) {
 775                 __set_bit(SCAN_HW_SCANNING, &local->scanning);
 776         } else if ((req->n_channels == 1) &&
 777                    (req->channels[0] == local->_oper_chandef.chan)) {
 778                 /*
 779                  * If we are scanning only on the operating channel
 780                  * then we do not need to stop normal activities
 781                  */
 782                 unsigned long next_delay;
 783
 784                 __set_bit(SCAN_ONCHANNEL_SCANNING, &local->scanning);
 785
 786                 ieee80211_recalc_idle(local);
 787
 788                 /* Notify driver scan is starting, keep order of operations
 789                  * same as normal software scan, in case that matters. */
 790                 drv_sw_scan_start(local, sdata, local->scan_addr);
 791
 792                 ieee80211_configure_filter(local); /* accept probe-responses */
 793
 794                 /* We need to ensure power level is at max for scanning. */
 795                 ieee80211_hw_config(local, 0);
 796
 797                 if ((req->channels[0]->flags & (IEEE80211_CHAN_NO_IR |
 798                                                 IEEE80211_CHAN_RADAR)) ||
 799                     !req->n_ssids) {
 800                         next_delay = IEEE80211_PASSIVE_CHANNEL_TIME;
 801                         if (req->n_ssids)
 802                                 set_bit(SCAN_BEACON_WAIT, &local->scanning);
 803                 } else {
 804                         ieee80211_scan_state_send_probe(local, &next_delay);
 805                         next_delay = IEEE80211_CHANNEL_TIME;
 806                 }
 807
 808                 /* Now, just wait a bit and we are all done! */
 809                 ieee80211_queue_delayed_work(&local->hw, &local->scan_work,
 810                                              next_delay);
 811                 return 0;
 812         } else {
 813                 /* Do normal software scan */
 814                 __set_bit(SCAN_SW_SCANNING, &local->scanning);
 815         }
 816
 817         ieee80211_recalc_idle(local);
 818
 819         if (hw_scan) {
 820                 WARN_ON(!ieee80211_prep_hw_scan(sdata));
 821                 rc = drv_hw_scan(local, sdata, local->hw_scan_req);
 822         } else {
 823                 rc = ieee80211_start_sw_scan(local, sdata);
 824         }
 825
 826         if (rc) {
 827                 kfree(local->hw_scan_req);
 828                 local->hw_scan_req = NULL;
 829                 local->scanning = 0;
 830
 831                 ieee80211_recalc_idle(local);
 832
 833                 local->scan_req = NULL;
 834                 RCU_INIT_POINTER(local->scan_sdata, NULL);
 835         }
 836
 837         if (hw_scan && rc == 1) {
 838                 /*
 839                  * we can't fall back to software for P2P-GO
 840                  * as it must update NoA etc.
 841                  */
 842                 if (ieee80211_vif_type_p2p(&sdata->vif) ==
 843                                 NL80211_IFTYPE_P2P_GO)
 844                         return -EOPNOTSUPP;
 845                 hw_scan = false;
 846                 goto again;
 847         }
 848
 849         return rc;
 850 }
 851
 852 static unsigned long
 853 ieee80211_scan_get_channel_time(struct ieee80211_channel *chan)
 854 {
 855         /*
 856          * TODO: channel switching also consumes quite some time,
 857          * add that delay as well to get a better estimation
 858          */
 859         if (chan->flags & (IEEE80211_CHAN_NO_IR | IEEE80211_CHAN_RADAR))
 860                 return IEEE80211_PASSIVE_CHANNEL_TIME;
 861         return IEEE80211_PROBE_DELAY + IEEE80211_CHANNEL_TIME;
 862 }
 863
 864 static void ieee80211_scan_state_decision(struct ieee80211_local *local,
 865                                           unsigned long *next_delay)
 866 {
 867         bool associated = false;
 868         bool tx_empty = true;
 869         bool bad_latency;
 870         struct ieee80211_sub_if_data *sdata;
 871         struct ieee80211_channel *next_chan;
 872         enum mac80211_scan_state next_scan_state;
 873         struct cfg80211_scan_request *scan_req;
 874
 875         /*
 876          * check if at least one STA interface is associated,
 877          * check if at least one STA interface has pending tx frames
 878          * and grab the lowest used beacon interval
 879          */
 880         mutex_lock(&local->iflist_mtx);
 881         list_for_each_entry(sdata, &local->interfaces, list) {
 882                 if (!ieee80211_sdata_running(sdata))
 883                         continue;
 884
 885                 if (sdata->vif.type == NL80211_IFTYPE_STATION) {
 886                         if (sdata->u.mgd.associated) {
 887                                 associated = true;
 888
 889                                 if (!qdisc_all_tx_empty(sdata->dev)) {
 890                                         tx_empty = false;
 891                                         break;
 892                                 }
 893                         }
 894                 }
 895         }
 896         mutex_unlock(&local->iflist_mtx);
 897
 898         scan_req = rcu_dereference_protected(local->scan_req,
 899                                              lockdep_is_held(&local->mtx));
 900
 901         next_chan = scan_req->channels[local->scan_channel_idx];
 902
 903         /*
 904          * we're currently scanning a different channel, let's
 905          * see if we can scan another channel without interfering
 906          * with the current traffic situation.
 907          *
 908          * Keep good latency, do not stay off-channel more than 125 ms.
 909          */
 910
 911         bad_latency = time_after(jiffies +
 912                                  ieee80211_scan_get_channel_time(next_chan),
 913                                  local->leave_oper_channel_time + HZ / 8);
 914
 915         if (associated && !tx_empty) {
 916                 if (scan_req->flags & NL80211_SCAN_FLAG_LOW_PRIORITY)
 917                         next_scan_state = SCAN_ABORT;
 918                 else
 919                         next_scan_state = SCAN_SUSPEND;
 920         } else if (associated && bad_latency) {
 921                 next_scan_state = SCAN_SUSPEND;
 922         } else {
 923                 next_scan_state = SCAN_SET_CHANNEL;
 924         }
 925
 926         local->next_scan_state = next_scan_state;
 927
 928         *next_delay = 0;
 929 }
 930
 931 static void ieee80211_scan_state_set_channel(struct ieee80211_local *local,
 932                                              unsigned long *next_delay)
 933 {
 934         int skip;
 935         struct ieee80211_channel *chan;
 936         enum nl80211_bss_scan_width oper_scan_width;
 937         struct cfg80211_scan_request *scan_req;
 938
 939         scan_req = rcu_dereference_protected(local->scan_req,
 940                                              lockdep_is_held(&local->mtx));
 941
 942         skip = 0;
 943         chan = scan_req->channels[local->scan_channel_idx];
 944
 945         local->scan_chandef.chan = chan;
 946         local->scan_chandef.center_freq1 = chan->center_freq;
 947         local->scan_chandef.freq1_offset = chan->freq_offset;
 948         local->scan_chandef.center_freq2 = 0;
 949
 950         /* For scanning on the S1G band, ignore scan_width (which is constant
 951          * across all channels) for now since channel width is specific to each
 952          * channel. Detect the required channel width here and likely revisit
 953          * later. Maybe scan_width could be used to build the channel scan list?
 954          */
 955         if (chan->band == NL80211_BAND_S1GHZ) {
 956                 local->scan_chandef.width = ieee80211_s1g_channel_width(chan);
 957                 goto set_channel;
 958         }
 959
 960         switch (scan_req->scan_width) {
 961         case NL80211_BSS_CHAN_WIDTH_5:
 962                 local->scan_chandef.width = NL80211_CHAN_WIDTH_5;
 963                 break;
 964         case NL80211_BSS_CHAN_WIDTH_10:
 965                 local->scan_chandef.width = NL80211_CHAN_WIDTH_10;
 966                 break;
 967         default:
 968         case NL80211_BSS_CHAN_WIDTH_20:
 969                 /* If scanning on oper channel, use whatever channel-type
 970                  * is currently in use.
 971                  */
 972                 oper_scan_width = cfg80211_chandef_to_scan_width(
 973                                         &local->_oper_chandef);
 974                 if (chan == local->_oper_chandef.chan &&
 975                     oper_scan_width == scan_req->scan_width)
 976                         local->scan_chandef = local->_oper_chandef;
 977                 else
 978                         local->scan_chandef.width = NL80211_CHAN_WIDTH_20_NOHT;
 979                 break;
 980         case NL80211_BSS_CHAN_WIDTH_1:
 981         case NL80211_BSS_CHAN_WIDTH_2:
 982                 /* shouldn't get here, S1G handled above */
 983                 WARN_ON(1);
 984                 break;
 985         }
 986
 987 set_channel:
 988         if (ieee80211_hw_config(local, IEEE80211_CONF_CHANGE_CHANNEL))
 989                 skip = 1;
 990
 991         /* advance state machine to next channel/band */
 992         local->scan_channel_idx++;
 993
 994         if (skip) {
 995                 /* if we skip this channel return to the decision state */
 996                 local->next_scan_state = SCAN_DECISION;
 997                 return;
 998         }
 999
1000         /*
1001          * Probe delay is used to update the NAV, cf. 11.1.3.2.2
1002          * (which unfortunately doesn't say _why_ step a) is done,
1003          * but it waits for the probe delay or until a frame is
1004          * received - and the received frame would update the NAV).
1005          * For now, we do not support waiting until a frame is
1006          * received.
1007          *
1008          * In any case, it is not necessary for a passive scan.
1009          */
1010         if ((chan->flags & (IEEE80211_CHAN_NO_IR | IEEE80211_CHAN_RADAR)) ||
1011             !scan_req->n_ssids) {
1012                 *next_delay = IEEE80211_PASSIVE_CHANNEL_TIME;
1013                 local->next_scan_state = SCAN_DECISION;
1014                 if (scan_req->n_ssids)
1015                         set_bit(SCAN_BEACON_WAIT, &local->scanning);
1016                 return;
1017         }
1018
1019         /* active scan, send probes */
1020         *next_delay = IEEE80211_PROBE_DELAY;
1021         local->next_scan_state = SCAN_SEND_PROBE;
1022 }
1023
1024 static void ieee80211_scan_state_suspend(struct ieee80211_local *local,
1025                                          unsigned long *next_delay)
1026 {
1027         /* switch back to the operating channel */
1028         local->scan_chandef.chan = NULL;
1029         ieee80211_hw_config(local, IEEE80211_CONF_CHANGE_CHANNEL);
1030
1031         /* disable PS */
1032         ieee80211_offchannel_return(local);
1033
1034         *next_delay = HZ / 5;
1035         /* afterwards, resume scan & go to next channel */
1036         local->next_scan_state = SCAN_RESUME;
1037 }
1038
1039 static void ieee80211_scan_state_resume(struct ieee80211_local *local,
1040                                         unsigned long *next_delay)
1041 {
1042         ieee80211_offchannel_stop_vifs(local);
1043
1044         if (local->ops->flush) {
1045                 ieee80211_flush_queues(local, NULL, false);
1046                 *next_delay = 0;
1047         } else
1048                 *next_delay = HZ / 10;
1049
1050         /* remember when we left the operating channel */
1051         local->leave_oper_channel_time = jiffies;
1052
1053         /* advance to the next channel to be scanned */
1054         local->next_scan_state = SCAN_SET_CHANNEL;
1055 }
1056
1057 void ieee80211_scan_work(struct work_struct *work)
1058 {
1059         struct ieee80211_local *local =
1060                 container_of(work, struct ieee80211_local, scan_work.work);
1061         struct ieee80211_sub_if_data *sdata;
1062         struct cfg80211_scan_request *scan_req;
1063         unsigned long next_delay = 0;
1064         bool aborted;
1065
1066         mutex_lock(&local->mtx);
1067
1068         if (!ieee80211_can_run_worker(local)) {
1069                 aborted = true;
1070                 goto out_complete;
1071         }
1072
1073         sdata = rcu_dereference_protected(local->scan_sdata,
1074                                           lockdep_is_held(&local->mtx));
1075         scan_req = rcu_dereference_protected(local->scan_req,
1076                                              lockdep_is_held(&local->mtx));
1077
1078         /* When scanning on-channel, the first-callback means completed. */
1079         if (test_bit(SCAN_ONCHANNEL_SCANNING, &local->scanning)) {
1080                 aborted = test_and_clear_bit(SCAN_ABORTED, &local->scanning);
1081                 goto out_complete;
1082         }
1083
1084         if (test_and_clear_bit(SCAN_COMPLETED, &local->scanning)) {
1085                 aborted = test_and_clear_bit(SCAN_ABORTED, &local->scanning);
1086                 goto out_complete;
1087         }
1088
1089         if (!sdata || !scan_req)
1090                 goto out;
1091
1092         if (!local->scanning) {
1093                 int rc;
1094
1095                 RCU_INIT_POINTER(local->scan_req, NULL);
1096                 RCU_INIT_POINTER(local->scan_sdata, NULL);
1097
1098                 rc = __ieee80211_start_scan(sdata, scan_req);
1099                 if (rc) {
1100                         /* need to complete scan in cfg80211 */
1101                         rcu_assign_pointer(local->scan_req, scan_req);
1102                         aborted = true;
1103                         goto out_complete;
1104                 } else
1105                         goto out;
1106         }
1107
1108         clear_bit(SCAN_BEACON_WAIT, &local->scanning);
1109
1110         /*
1111          * as long as no delay is required advance immediately
1112          * without scheduling a new work
1113          */
1114         do {
1115                 if (!ieee80211_sdata_running(sdata)) {
1116                         aborted = true;
1117                         goto out_complete;
1118                 }
1119
1120                 if (test_and_clear_bit(SCAN_BEACON_DONE, &local->scanning) &&
1121                     local->next_scan_state == SCAN_DECISION)
1122                         local->next_scan_state = SCAN_SEND_PROBE;
1123
1124                 switch (local->next_scan_state) {
1125                 case SCAN_DECISION:
1126                         /* if no more bands/channels left, complete scan */
1127                         if (local->scan_channel_idx >= scan_req->n_channels) {
1128                                 aborted = false;
1129                                 goto out_complete;
1130                         }
1131                         ieee80211_scan_state_decision(local, &next_delay);
1132                         break;
1133                 case SCAN_SET_CHANNEL:
1134                         ieee80211_scan_state_set_channel(local, &next_delay);
1135                         break;
1136                 case SCAN_SEND_PROBE:
1137                         ieee80211_scan_state_send_probe(local, &next_delay);
1138                         break;
1139                 case SCAN_SUSPEND:
1140                         ieee80211_scan_state_suspend(local, &next_delay);
1141                         break;
1142                 case SCAN_RESUME:
1143                         ieee80211_scan_state_resume(local, &next_delay);
1144                         break;
1145                 case SCAN_ABORT:
1146                         aborted = true;
1147                         goto out_complete;
1148                 }
1149         } while (next_delay == 0);
1150
1151         ieee80211_queue_delayed_work(&local->hw, &local->scan_work, next_delay);
1152         goto out;
1153
1154 out_complete:
1155         __ieee80211_scan_completed(&local->hw, aborted);
1156 out:
1157         mutex_unlock(&local->mtx);
1158 }
1159
1160 int ieee80211_request_scan(struct ieee80211_sub_if_data *sdata,
1161                            struct cfg80211_scan_request *req)
1162 {
1163         int res;
1164
1165         mutex_lock(&sdata->local->mtx);
1166         res = __ieee80211_start_scan(sdata, req);
1167         mutex_unlock(&sdata->local->mtx);
1168
1169         return res;
1170 }
1171
1172 int ieee80211_request_ibss_scan(struct ieee80211_sub_if_data *sdata,
1173                                 const u8 *ssid, u8 ssid_len,
1174                                 struct ieee80211_channel **channels,
1175                                 unsigned int n_channels,
1176                                 enum nl80211_bss_scan_width scan_width)
1177 {
1178         struct ieee80211_local *local = sdata->local;
1179         int ret = -EBUSY, i, n_ch = 0;
1180         enum nl80211_band band;
1181
1182         mutex_lock(&local->mtx);
1183
1184         /* busy scanning */
1185         if (local->scan_req)
1186                 goto unlock;
1187
1188         /* fill internal scan request */
1189         if (!channels) {
1190                 int max_n;
1191
1192                 for (band = 0; band < NUM_NL80211_BANDS; band++) {
1193                         if (!local->hw.wiphy->bands[band] ||
1194                             band == NL80211_BAND_6GHZ)
1195                                 continue;
1196
1197                         max_n = local->hw.wiphy->bands[band]->n_channels;
1198                         for (i = 0; i < max_n; i++) {
1199                                 struct ieee80211_channel *tmp_ch =
1200                                     &local->hw.wiphy->bands[band]->channels[i];
1201
1202                                 if (tmp_ch->flags & (IEEE80211_CHAN_NO_IR |
1203                                                      IEEE80211_CHAN_DISABLED))
1204                                         continue;
1205
1206                                 local->int_scan_req->channels[n_ch] = tmp_ch;
1207                                 n_ch++;
1208                         }
1209                 }
1210
1211                 if (WARN_ON_ONCE(n_ch == 0))
1212                         goto unlock;
1213
1214                 local->int_scan_req->n_channels = n_ch;
1215         } else {
1216                 for (i = 0; i < n_channels; i++) {
1217                         if (channels[i]->flags & (IEEE80211_CHAN_NO_IR |
1218                                                   IEEE80211_CHAN_DISABLED))
1219                                 continue;
1220
1221                         local->int_scan_req->channels[n_ch] = channels[i];
1222                         n_ch++;
1223                 }
1224
1225                 if (WARN_ON_ONCE(n_ch == 0))
1226                         goto unlock;
1227
1228                 local->int_scan_req->n_channels = n_ch;
1229         }
1230
1231         local->int_scan_req->ssids = &local->scan_ssid;
1232         local->int_scan_req->n_ssids = 1;
1233         local->int_scan_req->scan_width = scan_width;
1234         memcpy(local->int_scan_req->ssids[0].ssid, ssid, IEEE80211_MAX_SSID_LEN);
1235         local->int_scan_req->ssids[0].ssid_len = ssid_len;
1236
1237         ret = __ieee80211_start_scan(sdata, sdata->local->int_scan_req);
1238  unlock:
1239         mutex_unlock(&local->mtx);
1240         return ret;
1241 }
1242
1243 /*
1244  * Only call this function when a scan can't be queued -- under RTNL.
1245  */
1246 void ieee80211_scan_cancel(struct ieee80211_local *local)
1247 {
1248         /*
1249          * We are canceling software scan, or deferred scan that was not
1250          * yet really started (see __ieee80211_start_scan ).
1251          *
1252          * Regarding hardware scan:
1253          * - we can not call  __ieee80211_scan_completed() as when
1254          *   SCAN_HW_SCANNING bit is set this function change
1255          *   local->hw_scan_req to operate on 5G band, what race with
1256          *   driver which can use local->hw_scan_req
1257          *
1258          * - we can not cancel scan_work since driver can schedule it
1259          *   by ieee80211_scan_completed(..., true) to finish scan
1260          *
1261          * Hence we only call the cancel_hw_scan() callback, but the low-level
1262          * driver is still responsible for calling ieee80211_scan_completed()
1263          * after the scan was completed/aborted.
1264          */
1265
1266         mutex_lock(&local->mtx);
1267         if (!local->scan_req)
1268                 goto out;
1269
1270         /*
1271          * We have a scan running and the driver already reported completion,
1272          * but the worker hasn't run yet or is stuck on the mutex - mark it as
1273          * cancelled.
1274          */
1275         if (test_bit(SCAN_HW_SCANNING, &local->scanning) &&
1276             test_bit(SCAN_COMPLETED, &local->scanning)) {
1277                 set_bit(SCAN_HW_CANCELLED, &local->scanning);
1278                 goto out;
1279         }
1280
1281         if (test_bit(SCAN_HW_SCANNING, &local->scanning)) {
1282                 /*
1283                  * Make sure that __ieee80211_scan_completed doesn't trigger a
1284                  * scan on another band.
1285                  */
1286                 set_bit(SCAN_HW_CANCELLED, &local->scanning);
1287                 if (local->ops->cancel_hw_scan)
1288                         drv_cancel_hw_scan(local,
1289                                 rcu_dereference_protected(local->scan_sdata,
1290                                                 lockdep_is_held(&local->mtx)));
1291                 goto out;
1292         }
1293
1294         /*
1295          * If the work is currently running, it must be blocked on
1296          * the mutex, but we'll set scan_sdata = NULL and it'll
1297          * simply exit once it acquires the mutex.
1298          */
1299         cancel_delayed_work(&local->scan_work);
1300         /* and clean up */
1301         memset(&local->scan_info, 0, sizeof(local->scan_info));
1302         __ieee80211_scan_completed(&local->hw, true);
1303 out:
1304         mutex_unlock(&local->mtx);
1305 }
1306
1307 int __ieee80211_request_sched_scan_start(struct ieee80211_sub_if_data *sdata,
1308                                         struct cfg80211_sched_scan_request *req)
1309 {
1310         struct ieee80211_local *local = sdata->local;
1311         struct ieee80211_scan_ies sched_scan_ies = {};
1312         struct cfg80211_chan_def chandef;
1313         int ret, i, iebufsz, num_bands = 0;
1314         u32 rate_masks[NUM_NL80211_BANDS] = {};
1315         u8 bands_used = 0;
1316         u8 *ie;
1317         u32 flags = 0;
1318
1319         iebufsz = local->scan_ies_len + req->ie_len;
1320
1321         lockdep_assert_held(&local->mtx);
1322
1323         if (!local->ops->sched_scan_start)
1324                 return -ENOTSUPP;
1325
1326         for (i = 0; i < NUM_NL80211_BANDS; i++) {
1327                 if (local->hw.wiphy->bands[i]) {
1328                         bands_used |= BIT(i);
1329                         rate_masks[i] = (u32) -1;
1330                         num_bands++;
1331                 }
1332         }
1333
1334         if (req->flags & NL80211_SCAN_FLAG_MIN_PREQ_CONTENT)
1335                 flags |= IEEE80211_PROBE_FLAG_MIN_CONTENT;
1336
1337         ie = kcalloc(iebufsz, num_bands, GFP_KERNEL);
1338         if (!ie) {
1339                 ret = -ENOMEM;
1340                 goto out;
1341         }
1342
1343         ieee80211_prepare_scan_chandef(&chandef, req->scan_width);
1344
1345         ieee80211_build_preq_ies(sdata, ie, num_bands * iebufsz,
1346                                  &sched_scan_ies, req->ie,
1347                                  req->ie_len, bands_used, rate_masks, &chandef,
1348                                  flags);
1349
1350         ret = drv_sched_scan_start(local, sdata, req, &sched_scan_ies);
1351         if (ret == 0) {
1352                 rcu_assign_pointer(local->sched_scan_sdata, sdata);
1353                 rcu_assign_pointer(local->sched_scan_req, req);
1354         }
1355
1356         kfree(ie);
1357
1358 out:
1359         if (ret) {
1360                 /* Clean in case of failure after HW restart or upon resume. */
1361                 RCU_INIT_POINTER(local->sched_scan_sdata, NULL);
1362                 RCU_INIT_POINTER(local->sched_scan_req, NULL);
1363         }
1364
1365         return ret;
1366 }
1367
1368 int ieee80211_request_sched_scan_start(struct ieee80211_sub_if_data *sdata,
1369                                        struct cfg80211_sched_scan_request *req)
1370 {
1371         struct ieee80211_local *local = sdata->local;
1372         int ret;
1373
1374         mutex_lock(&local->mtx);
1375
1376         if (rcu_access_pointer(local->sched_scan_sdata)) {
1377                 mutex_unlock(&local->mtx);
1378                 return -EBUSY;
1379         }
1380
1381         ret = __ieee80211_request_sched_scan_start(sdata, req);
1382
1383         mutex_unlock(&local->mtx);
1384         return ret;
1385 }
1386
1387 int ieee80211_request_sched_scan_stop(struct ieee80211_local *local)
1388 {
1389         struct ieee80211_sub_if_data *sched_scan_sdata;
1390         int ret = -ENOENT;
1391
1392         mutex_lock(&local->mtx);
1393
1394         if (!local->ops->sched_scan_stop) {
1395                 ret = -ENOTSUPP;
1396                 goto out;
1397         }
1398
1399         /* We don't want to restart sched scan anymore. */
1400         RCU_INIT_POINTER(local->sched_scan_req, NULL);
1401
1402         sched_scan_sdata = rcu_dereference_protected(local->sched_scan_sdata,
1403                                                 lockdep_is_held(&local->mtx));
1404         if (sched_scan_sdata) {
1405                 ret = drv_sched_scan_stop(local, sched_scan_sdata);
1406                 if (!ret)
1407                         RCU_INIT_POINTER(local->sched_scan_sdata, NULL);
1408         }
1409 out:
1410         mutex_unlock(&local->mtx);
1411
1412         return ret;
1413 }
1414
1415 void ieee80211_sched_scan_results(struct ieee80211_hw *hw)
1416 {
1417         struct ieee80211_local *local = hw_to_local(hw);
1418
1419         trace_api_sched_scan_results(local);
1420
1421         cfg80211_sched_scan_results(hw->wiphy, 0);
1422 }
1423 EXPORT_SYMBOL(ieee80211_sched_scan_results);
1424
1425 void ieee80211_sched_scan_end(struct ieee80211_local *local)
1426 {
1427         mutex_lock(&local->mtx);
1428
1429         if (!rcu_access_pointer(local->sched_scan_sdata)) {
1430                 mutex_unlock(&local->mtx);
1431                 return;
1432         }
1433
1434         RCU_INIT_POINTER(local->sched_scan_sdata, NULL);
1435
1436         /* If sched scan was aborted by the driver. */
1437         RCU_INIT_POINTER(local->sched_scan_req, NULL);
1438
1439         mutex_unlock(&local->mtx);
1440
1441         cfg80211_sched_scan_stopped(local->hw.wiphy, 0);
1442 }
1443
1444 void ieee80211_sched_scan_stopped_work(struct work_struct *work)
1445 {
1446         struct ieee80211_local *local =
1447                 container_of(work, struct ieee80211_local,
1448                              sched_scan_stopped_work);
1449
1450         ieee80211_sched_scan_end(local);
1451 }
1452
1453 void ieee80211_sched_scan_stopped(struct ieee80211_hw *hw)
1454 {
1455         struct ieee80211_local *local = hw_to_local(hw);
1456
1457         trace_api_sched_scan_stopped(local);
1458
1459         /*
1460          * this shouldn't really happen, so for simplicity
1461          * simply ignore it, and let mac80211 reconfigure
1462          * the sched scan later on.
1463          */
1464         if (local->in_reconfig)
1465                 return;
1466
1467         schedule_work(&local->sched_scan_stopped_work);
1468 }
1469 EXPORT_SYMBOL(ieee80211_sched_scan_stopped);