net/mac80211/scan.c

   1 /*
   2  * Scanning implementation
   3  *
   4  * Copyright 2003, Jouni Malinen <jkmaline@cc.hut.fi>
   5  * Copyright 2004, Instant802 Networks, Inc.
   6  * Copyright 2005, Devicescape Software, Inc.
   7  * Copyright 2006-2007  Jiri Benc <jbenc@suse.cz>
   8  * Copyright 2007, Michael Wu <flamingice@sourmilk.net>
   9  * Copyright 2013-2015  Intel Mobile Communications GmbH
  10  * Copyright 2016-2017  Intel Deutschland GmbH
  11  * Copyright (C) 2018-2019 Intel Corporation
  12  *
  13  * This program is free software; you can redistribute it and/or modify
  14  * it under the terms of the GNU General Public License version 2 as
  15  * published by the Free Software Foundation.
  16  */
  17
  18 #include <linux/if_arp.h>
  19 #include <linux/etherdevice.h>
  20 #include <linux/rtnetlink.h>
  21 #include <net/sch_generic.h>
  22 #include <linux/slab.h>
  23 #include <linux/export.h>
  24 #include <linux/random.h>
  25 #include <net/mac80211.h>
  26
  27 #include "ieee80211_i.h"
  28 #include "driver-ops.h"
  29 #include "mesh.h"
  30
  31 #define IEEE80211_PROBE_DELAY (HZ / 33)
  32 #define IEEE80211_CHANNEL_TIME (HZ / 33)
  33 #define IEEE80211_PASSIVE_CHANNEL_TIME (HZ / 9)
  34
  35 void ieee80211_rx_bss_put(struct ieee80211_local *local,
  36                           struct ieee80211_bss *bss)
  37 {
  38         if (!bss)
  39                 return;
  40         cfg80211_put_bss(local->hw.wiphy,
  41                          container_of((void *)bss, struct cfg80211_bss, priv));
  42 }
  43
  44 static bool is_uapsd_supported(struct ieee802_11_elems *elems)
  45 {
  46         u8 qos_info;
  47
  48         if (elems->wmm_info && elems->wmm_info_len == 7
  49             && elems->wmm_info[5] == 1)
  50                 qos_info = elems->wmm_info[6];
  51         else if (elems->wmm_param && elems->wmm_param_len == 24
  52                  && elems->wmm_param[5] == 1)
  53                 qos_info = elems->wmm_param[6];
  54         else
  55                 /* no valid wmm information or parameter element found */
  56                 return false;
  57
  58         return qos_info & IEEE80211_WMM_IE_AP_QOSINFO_UAPSD;
  59 }
  60
  61 static void
  62 ieee80211_update_bss_from_elems(struct ieee80211_local *local,
  63                                 struct ieee80211_bss *bss,
  64                                 struct ieee802_11_elems *elems,
  65                                 struct ieee80211_rx_status *rx_status,
  66                                 bool beacon)
  67 {
  68         int clen, srlen;
  69
  70         if (beacon)
  71                 bss->device_ts_beacon = rx_status->device_timestamp;
  72         else
  73                 bss->device_ts_presp = rx_status->device_timestamp;
  74
  75         if (elems->parse_error) {
  76                 if (beacon)
  77                         bss->corrupt_data |= IEEE80211_BSS_CORRUPT_BEACON;
  78                 else
  79                         bss->corrupt_data |= IEEE80211_BSS_CORRUPT_PROBE_RESP;
  80         } else {
  81                 if (beacon)
  82                         bss->corrupt_data &= ~IEEE80211_BSS_CORRUPT_BEACON;
  83                 else
  84                         bss->corrupt_data &= ~IEEE80211_BSS_CORRUPT_PROBE_RESP;
  85         }
  86
  87         /* save the ERP value so that it is available at association time */
  88         if (elems->erp_info && (!elems->parse_error ||
  89                                 !(bss->valid_data & IEEE80211_BSS_VALID_ERP))) {
  90                 bss->erp_value = elems->erp_info[0];
  91                 bss->has_erp_value = true;
  92                 if (!elems->parse_error)
  93                         bss->valid_data |= IEEE80211_BSS_VALID_ERP;
  94         }
  95
  96         /* replace old supported rates if we get new values */
  97         if (!elems->parse_error ||
  98             !(bss->valid_data & IEEE80211_BSS_VALID_RATES)) {
  99                 srlen = 0;
 100                 if (elems->supp_rates) {
 101                         clen = IEEE80211_MAX_SUPP_RATES;
 102                         if (clen > elems->supp_rates_len)
 103                                 clen = elems->supp_rates_len;
 104                         memcpy(bss->supp_rates, elems->supp_rates, clen);
 105                         srlen += clen;
 106                 }
 107                 if (elems->ext_supp_rates) {
 108                         clen = IEEE80211_MAX_SUPP_RATES - srlen;
 109                         if (clen > elems->ext_supp_rates_len)
 110                                 clen = elems->ext_supp_rates_len;
 111                         memcpy(bss->supp_rates + srlen, elems->ext_supp_rates,
 112                                clen);
 113                         srlen += clen;
 114                 }
 115                 if (srlen) {
 116                         bss->supp_rates_len = srlen;
 117                         if (!elems->parse_error)
 118                                 bss->valid_data |= IEEE80211_BSS_VALID_RATES;
 119                 }
 120         }
 121
 122         if (!elems->parse_error ||
 123             !(bss->valid_data & IEEE80211_BSS_VALID_WMM)) {
 124                 bss->wmm_used = elems->wmm_param || elems->wmm_info;
 125                 bss->uapsd_supported = is_uapsd_supported(elems);
 126                 if (!elems->parse_error)
 127                         bss->valid_data |= IEEE80211_BSS_VALID_WMM;
 128         }
 129
 130         if (beacon) {
 131                 struct ieee80211_supported_band *sband =
 132                         local->hw.wiphy->bands[rx_status->band];
 133                 if (!(rx_status->encoding == RX_ENC_HT) &&
 134                     !(rx_status->encoding == RX_ENC_VHT))
 135                         bss->beacon_rate =
 136                                 &sband->bitrates[rx_status->rate_idx];
 137         }
 138 }
 139
 140 struct ieee80211_bss *
 141 ieee80211_bss_info_update(struct ieee80211_local *local,
 142                           struct ieee80211_rx_status *rx_status,
 143                           struct ieee80211_mgmt *mgmt, size_t len,
 144                           struct ieee80211_channel *channel)
 145 {
 146         bool beacon = ieee80211_is_beacon(mgmt->frame_control);
 147         struct cfg80211_bss *cbss, *non_tx_cbss;
 148         struct ieee80211_bss *bss, *non_tx_bss;
 149         struct cfg80211_inform_bss bss_meta = {
 150                 .boottime_ns = rx_status->boottime_ns,
 151         };
 152         bool signal_valid;
 153         struct ieee80211_sub_if_data *scan_sdata;
 154         struct ieee802_11_elems elems;
 155         size_t baselen;
 156         u8 *elements;
 157
 158         if (rx_status->flag & RX_FLAG_NO_SIGNAL_VAL)
 159                 bss_meta.signal = 0; /* invalid signal indication */
 160         else if (ieee80211_hw_check(&local->hw, SIGNAL_DBM))
 161                 bss_meta.signal = rx_status->signal * 100;
 162         else if (ieee80211_hw_check(&local->hw, SIGNAL_UNSPEC))
 163                 bss_meta.signal = (rx_status->signal * 100) / local->hw.max_signal;
 164
 165         bss_meta.scan_width = NL80211_BSS_CHAN_WIDTH_20;
 166         if (rx_status->bw == RATE_INFO_BW_5)
 167                 bss_meta.scan_width = NL80211_BSS_CHAN_WIDTH_5;
 168         else if (rx_status->bw == RATE_INFO_BW_10)
 169                 bss_meta.scan_width = NL80211_BSS_CHAN_WIDTH_10;
 170
 171         bss_meta.chan = channel;
 172
 173         rcu_read_lock();
 174         scan_sdata = rcu_dereference(local->scan_sdata);
 175         if (scan_sdata && scan_sdata->vif.type == NL80211_IFTYPE_STATION &&
 176             scan_sdata->vif.bss_conf.assoc &&
 177             ieee80211_have_rx_timestamp(rx_status)) {
 178                 bss_meta.parent_tsf =
 179                         ieee80211_calculate_rx_timestamp(local, rx_status,
 180                                                          len + FCS_LEN, 24);
 181                 ether_addr_copy(bss_meta.parent_bssid,
 182                                 scan_sdata->vif.bss_conf.bssid);
 183         }
 184         rcu_read_unlock();
 185
 186         cbss = cfg80211_inform_bss_frame_data(local->hw.wiphy, &bss_meta,
 187                                               mgmt, len, GFP_ATOMIC);
 188         if (!cbss)
 189                 return NULL;
 190
 191         if (ieee80211_is_probe_resp(mgmt->frame_control)) {
 192                 elements = mgmt->u.probe_resp.variable;
 193                 baselen = offsetof(struct ieee80211_mgmt,
 194                                    u.probe_resp.variable);
 195         } else {
 196                 baselen = offsetof(struct ieee80211_mgmt, u.beacon.variable);
 197                 elements = mgmt->u.beacon.variable;
 198         }
 199
 200         if (baselen > len)
 201                 return NULL;
 202
 203         ieee802_11_parse_elems(elements, len - baselen, false, &elems,
 204                                mgmt->bssid, cbss->bssid);
 205
 206         /* In case the signal is invalid update the status */
 207         signal_valid = abs(channel->center_freq - cbss->channel->center_freq)
 208                 <= local->hw.wiphy->max_adj_channel_rssi_comp;
 209         if (!signal_valid)
 210                 rx_status->flag |= RX_FLAG_NO_SIGNAL_VAL;
 211
 212         bss = (void *)cbss->priv;
 213         ieee80211_update_bss_from_elems(local, bss, &elems, rx_status, beacon);
 214
 215         list_for_each_entry(non_tx_cbss, &cbss->nontrans_list, nontrans_list) {
 216                 non_tx_bss = (void *)non_tx_cbss->priv;
 217
 218                 ieee80211_update_bss_from_elems(local, non_tx_bss, &elems,
 219                                                 rx_status, beacon);
 220         }
 221
 222         return bss;
 223 }
 224
 225 static bool ieee80211_scan_accept_presp(struct ieee80211_sub_if_data *sdata,
 226                                         u32 scan_flags, const u8 *da)
 227 {
 228         if (!sdata)
 229                 return false;
 230         /* accept broadcast for OCE */
 231         if (scan_flags & NL80211_SCAN_FLAG_ACCEPT_BCAST_PROBE_RESP &&
 232             is_broadcast_ether_addr(da))
 233                 return true;
 234         if (scan_flags & NL80211_SCAN_FLAG_RANDOM_ADDR)
 235                 return true;
 236         return ether_addr_equal(da, sdata->vif.addr);
 237 }
 238
 239 void ieee80211_scan_rx(struct ieee80211_local *local, struct sk_buff *skb)
 240 {
 241         struct ieee80211_rx_status *rx_status = IEEE80211_SKB_RXCB(skb);
 242         struct ieee80211_sub_if_data *sdata1, *sdata2;
 243         struct ieee80211_mgmt *mgmt = (void *)skb->data;
 244         struct ieee80211_bss *bss;
 245         struct ieee80211_channel *channel;
 246
 247         if (skb->len < 24 ||
 248             (!ieee80211_is_probe_resp(mgmt->frame_control) &&
 249              !ieee80211_is_beacon(mgmt->frame_control)))
 250                 return;
 251
 252         sdata1 = rcu_dereference(local->scan_sdata);
 253         sdata2 = rcu_dereference(local->sched_scan_sdata);
 254
 255         if (likely(!sdata1 && !sdata2))
 256                 return;
 257
 258         if (ieee80211_is_probe_resp(mgmt->frame_control)) {
 259                 struct cfg80211_scan_request *scan_req;
 260                 struct cfg80211_sched_scan_request *sched_scan_req;
 261                 u32 scan_req_flags = 0, sched_scan_req_flags = 0;
 262
 263                 scan_req = rcu_dereference(local->scan_req);
 264                 sched_scan_req = rcu_dereference(local->sched_scan_req);
 265
 266                 if (scan_req)
 267                         scan_req_flags = scan_req->flags;
 268
 269                 if (sched_scan_req)
 270                         sched_scan_req_flags = sched_scan_req->flags;
 271
 272                 /* ignore ProbeResp to foreign address or non-bcast (OCE)
 273                  * unless scanning with randomised address
 274                  */
 275                 if (!ieee80211_scan_accept_presp(sdata1, scan_req_flags,
 276                                                  mgmt->da) &&
 277                     !ieee80211_scan_accept_presp(sdata2, sched_scan_req_flags,
 278                                                  mgmt->da))
 279                         return;
 280         }
 281
 282         channel = ieee80211_get_channel(local->hw.wiphy, rx_status->freq);
 283
 284         if (!channel || channel->flags & IEEE80211_CHAN_DISABLED)
 285                 return;
 286
 287         bss = ieee80211_bss_info_update(local, rx_status,
 288                                         mgmt, skb->len,
 289                                         channel);
 290         if (bss)
 291                 ieee80211_rx_bss_put(local, bss);
 292 }
 293
 294 static void
 295 ieee80211_prepare_scan_chandef(struct cfg80211_chan_def *chandef,
 296                                enum nl80211_bss_scan_width scan_width)
 297 {
 298         memset(chandef, 0, sizeof(*chandef));
 299         switch (scan_width) {
 300         case NL80211_BSS_CHAN_WIDTH_5:
 301                 chandef->width = NL80211_CHAN_WIDTH_5;
 302                 break;
 303         case NL80211_BSS_CHAN_WIDTH_10:
 304                 chandef->width = NL80211_CHAN_WIDTH_10;
 305                 break;
 306         default:
 307                 chandef->width = NL80211_CHAN_WIDTH_20_NOHT;
 308                 break;
 309         }
 310 }
 311
 312 /* return false if no more work */
 313 static bool ieee80211_prep_hw_scan(struct ieee80211_local *local)
 314 {
 315         struct cfg80211_scan_request *req;
 316         struct cfg80211_chan_def chandef;
 317         u8 bands_used = 0;
 318         int i, ielen, n_chans;
 319         u32 flags = 0;
 320
 321         req = rcu_dereference_protected(local->scan_req,
 322                                         lockdep_is_held(&local->mtx));
 323
 324         if (test_bit(SCAN_HW_CANCELLED, &local->scanning))
 325                 return false;
 326
 327         if (ieee80211_hw_check(&local->hw, SINGLE_SCAN_ON_ALL_BANDS)) {
 328                 for (i = 0; i < req->n_channels; i++) {
 329                         local->hw_scan_req->req.channels[i] = req->channels[i];
 330                         bands_used |= BIT(req->channels[i]->band);
 331                 }
 332
 333                 n_chans = req->n_channels;
 334         } else {
 335                 do {
 336                         if (local->hw_scan_band == NUM_NL80211_BANDS)
 337                                 return false;
 338
 339                         n_chans = 0;
 340
 341                         for (i = 0; i < req->n_channels; i++) {
 342                                 if (req->channels[i]->band !=
 343                                     local->hw_scan_band)
 344                                         continue;
 345                                 local->hw_scan_req->req.channels[n_chans] =
 346                                                         req->channels[i];
 347                                 n_chans++;
 348                                 bands_used |= BIT(req->channels[i]->band);
 349                         }
 350
 351                         local->hw_scan_band++;
 352                 } while (!n_chans);
 353         }
 354
 355         local->hw_scan_req->req.n_channels = n_chans;
 356         ieee80211_prepare_scan_chandef(&chandef, req->scan_width);
 357
 358         if (req->flags & NL80211_SCAN_FLAG_MIN_PREQ_CONTENT)
 359                 flags |= IEEE80211_PROBE_FLAG_MIN_CONTENT;
 360
 361         ielen = ieee80211_build_preq_ies(local,
 362                                          (u8 *)local->hw_scan_req->req.ie,
 363                                          local->hw_scan_ies_bufsize,
 364                                          &local->hw_scan_req->ies,
 365                                          req->ie, req->ie_len,
 366                                          bands_used, req->rates, &chandef,
 367                                          flags);
 368         local->hw_scan_req->req.ie_len = ielen;
 369         local->hw_scan_req->req.no_cck = req->no_cck;
 370         ether_addr_copy(local->hw_scan_req->req.mac_addr, req->mac_addr);
 371         ether_addr_copy(local->hw_scan_req->req.mac_addr_mask,
 372                         req->mac_addr_mask);
 373         ether_addr_copy(local->hw_scan_req->req.bssid, req->bssid);
 374
 375         return true;
 376 }
 377
 378 static void __ieee80211_scan_completed(struct ieee80211_hw *hw, bool aborted)
 379 {
 380         struct ieee80211_local *local = hw_to_local(hw);
 381         bool hw_scan = test_bit(SCAN_HW_SCANNING, &local->scanning);
 382         bool was_scanning = local->scanning;
 383         struct cfg80211_scan_request *scan_req;
 384         struct ieee80211_sub_if_data *scan_sdata;
 385         struct ieee80211_sub_if_data *sdata;
 386
 387         lockdep_assert_held(&local->mtx);
 388
 389         /*
 390          * It's ok to abort a not-yet-running scan (that
 391          * we have one at all will be verified by checking
 392          * local->scan_req next), but not to complete it
 393          * successfully.
 394          */
 395         if (WARN_ON(!local->scanning && !aborted))
 396                 aborted = true;
 397
 398         if (WARN_ON(!local->scan_req))
 399                 return;
 400
 401         if (hw_scan && !aborted &&
 402             !ieee80211_hw_check(&local->hw, SINGLE_SCAN_ON_ALL_BANDS) &&
 403             ieee80211_prep_hw_scan(local)) {
 404                 int rc;
 405
 406                 rc = drv_hw_scan(local,
 407                         rcu_dereference_protected(local->scan_sdata,
 408                                                   lockdep_is_held(&local->mtx)),
 409                         local->hw_scan_req);
 410
 411                 if (rc == 0)
 412                         return;
 413
 414                 /* HW scan failed and is going to be reported as aborted,
 415                  * so clear old scan info.
 416                  */
 417                 memset(&local->scan_info, 0, sizeof(local->scan_info));
 418                 aborted = true;
 419         }
 420
 421         kfree(local->hw_scan_req);
 422         local->hw_scan_req = NULL;
 423
 424         scan_req = rcu_dereference_protected(local->scan_req,
 425                                              lockdep_is_held(&local->mtx));
 426
 427         if (scan_req != local->int_scan_req) {
 428                 local->scan_info.aborted = aborted;
 429                 cfg80211_scan_done(scan_req, &local->scan_info);
 430         }
 431         RCU_INIT_POINTER(local->scan_req, NULL);
 432
 433         scan_sdata = rcu_dereference_protected(local->scan_sdata,
 434                                                lockdep_is_held(&local->mtx));
 435         RCU_INIT_POINTER(local->scan_sdata, NULL);
 436
 437         local->scanning = 0;
 438         local->scan_chandef.chan = NULL;
 439
 440         /* Set power back to normal operating levels. */
 441         ieee80211_hw_config(local, 0);
 442
 443         if (!hw_scan) {
 444                 ieee80211_configure_filter(local);
 445                 drv_sw_scan_complete(local, scan_sdata);
 446                 ieee80211_offchannel_return(local);
 447         }
 448
 449         ieee80211_recalc_idle(local);
 450
 451         ieee80211_mlme_notify_scan_completed(local);
 452         ieee80211_ibss_notify_scan_completed(local);
 453
 454         /* Requeue all the work that might have been ignored while
 455          * the scan was in progress; if there was none this will
 456          * just be a no-op for the particular interface.
 457          */
 458         list_for_each_entry_rcu(sdata, &local->interfaces, list) {
 459                 if (ieee80211_sdata_running(sdata))
 460                         ieee80211_queue_work(&sdata->local->hw, &sdata->work);
 461         }
 462
 463         if (was_scanning)
 464                 ieee80211_start_next_roc(local);
 465 }
 466
 467 void ieee80211_scan_completed(struct ieee80211_hw *hw,
 468                               struct cfg80211_scan_info *info)
 469 {
 470         struct ieee80211_local *local = hw_to_local(hw);
 471
 472         trace_api_scan_completed(local, info->aborted);
 473
 474         set_bit(SCAN_COMPLETED, &local->scanning);
 475         if (info->aborted)
 476                 set_bit(SCAN_ABORTED, &local->scanning);
 477
 478         memcpy(&local->scan_info, info, sizeof(*info));
 479
 480         ieee80211_queue_delayed_work(&local->hw, &local->scan_work, 0);
 481 }
 482 EXPORT_SYMBOL(ieee80211_scan_completed);
 483
 484 static int ieee80211_start_sw_scan(struct ieee80211_local *local,
 485                                    struct ieee80211_sub_if_data *sdata)
 486 {
 487         /* Software scan is not supported in multi-channel cases */
 488         if (local->use_chanctx)
 489                 return -EOPNOTSUPP;
 490
 491         /*
 492          * Hardware/driver doesn't support hw_scan, so use software
 493          * scanning instead. First send a nullfunc frame with power save
 494          * bit on so that AP will buffer the frames for us while we are not
 495          * listening, then send probe requests to each channel and wait for
 496          * the responses. After all channels are scanned, tune back to the
 497          * original channel and send a nullfunc frame with power save bit
 498          * off to trigger the AP to send us all the buffered frames.
 499          *
 500          * Note that while local->sw_scanning is true everything else but
 501          * nullfunc frames and probe requests will be dropped in
 502          * ieee80211_tx_h_check_assoc().
 503          */
 504         drv_sw_scan_start(local, sdata, local->scan_addr);
 505
 506         local->leave_oper_channel_time = jiffies;
 507         local->next_scan_state = SCAN_DECISION;
 508         local->scan_channel_idx = 0;
 509
 510         ieee80211_offchannel_stop_vifs(local);
 511
 512         /* ensure nullfunc is transmitted before leaving operating channel */
 513         ieee80211_flush_queues(local, NULL, false);
 514
 515         ieee80211_configure_filter(local);
 516
 517         /* We need to set power level at maximum rate for scanning. */
 518         ieee80211_hw_config(local, 0);
 519
 520         ieee80211_queue_delayed_work(&local->hw,
 521                                      &local->scan_work, 0);
 522
 523         return 0;
 524 }
 525
 526 static bool ieee80211_can_scan(struct ieee80211_local *local,
 527                                struct ieee80211_sub_if_data *sdata)
 528 {
 529         if (ieee80211_is_radar_required(local))
 530                 return false;
 531
 532         if (!list_empty(&local->roc_list))
 533                 return false;
 534
 535         if (sdata->vif.type == NL80211_IFTYPE_STATION &&
 536             sdata->u.mgd.flags & IEEE80211_STA_CONNECTION_POLL)
 537                 return false;
 538
 539         return true;
 540 }
 541
 542 void ieee80211_run_deferred_scan(struct ieee80211_local *local)
 543 {
 544         lockdep_assert_held(&local->mtx);
 545
 546         if (!local->scan_req || local->scanning)
 547                 return;
 548
 549         if (!ieee80211_can_scan(local,
 550                                 rcu_dereference_protected(
 551                                         local->scan_sdata,
 552                                         lockdep_is_held(&local->mtx))))
 553                 return;
 554
 555         ieee80211_queue_delayed_work(&local->hw, &local->scan_work,
 556                                      round_jiffies_relative(0));
 557 }
 558
 559 static void ieee80211_send_scan_probe_req(struct ieee80211_sub_if_data *sdata,
 560                                           const u8 *src, const u8 *dst,
 561                                           const u8 *ssid, size_t ssid_len,
 562                                           const u8 *ie, size_t ie_len,
 563                                           u32 ratemask, u32 flags, u32 tx_flags,
 564                                           struct ieee80211_channel *channel)
 565 {
 566         struct sk_buff *skb;
 567         u32 txdata_flags = 0;
 568
 569         skb = ieee80211_build_probe_req(sdata, src, dst, ratemask, channel,
 570                                         ssid, ssid_len,
 571                                         ie, ie_len, flags);
 572
 573         if (skb) {
 574                 if (flags & IEEE80211_PROBE_FLAG_RANDOM_SN) {
 575                         struct ieee80211_hdr *hdr = (void *)skb->data;
 576                         u16 sn = get_random_u32();
 577
 578                         txdata_flags |= IEEE80211_TX_NO_SEQNO;
 579                         hdr->seq_ctrl =
 580                                 cpu_to_le16(IEEE80211_SN_TO_SEQ(sn));
 581                 }
 582                 IEEE80211_SKB_CB(skb)->flags |= tx_flags;
 583                 ieee80211_tx_skb_tid_band(sdata, skb, 7, channel->band,
 584                                           txdata_flags);
 585         }
 586 }
 587
 588 static void ieee80211_scan_state_send_probe(struct ieee80211_local *local,
 589                                             unsigned long *next_delay)
 590 {
 591         int i;
 592         struct ieee80211_sub_if_data *sdata;
 593         struct cfg80211_scan_request *scan_req;
 594         enum nl80211_band band = local->hw.conf.chandef.chan->band;
 595         u32 flags = 0, tx_flags;
 596
 597         scan_req = rcu_dereference_protected(local->scan_req,
 598                                              lockdep_is_held(&local->mtx));
 599
 600         tx_flags = IEEE80211_TX_INTFL_OFFCHAN_TX_OK;
 601         if (scan_req->no_cck)
 602                 tx_flags |= IEEE80211_TX_CTL_NO_CCK_RATE;
 603         if (scan_req->flags & NL80211_SCAN_FLAG_MIN_PREQ_CONTENT)
 604                 flags |= IEEE80211_PROBE_FLAG_MIN_CONTENT;
 605         if (scan_req->flags & NL80211_SCAN_FLAG_RANDOM_SN)
 606                 flags |= IEEE80211_PROBE_FLAG_RANDOM_SN;
 607
 608         sdata = rcu_dereference_protected(local->scan_sdata,
 609                                           lockdep_is_held(&local->mtx));
 610
 611         for (i = 0; i < scan_req->n_ssids; i++)
 612                 ieee80211_send_scan_probe_req(
 613                         sdata, local->scan_addr, scan_req->bssid,
 614                         scan_req->ssids[i].ssid, scan_req->ssids[i].ssid_len,
 615                         scan_req->ie, scan_req->ie_len,
 616                         scan_req->rates[band], flags,
 617                         tx_flags, local->hw.conf.chandef.chan);
 618
 619         /*
 620          * After sending probe requests, wait for probe responses
 621          * on the channel.
 622          */
 623         *next_delay = IEEE80211_CHANNEL_TIME;
 624         local->next_scan_state = SCAN_DECISION;
 625 }
 626
 627 static int __ieee80211_start_scan(struct ieee80211_sub_if_data *sdata,
 628                                   struct cfg80211_scan_request *req)
 629 {
 630         struct ieee80211_local *local = sdata->local;
 631         bool hw_scan = local->ops->hw_scan;
 632         int rc;
 633
 634         lockdep_assert_held(&local->mtx);
 635
 636         if (local->scan_req || ieee80211_is_radar_required(local))
 637                 return -EBUSY;
 638
 639         if (!ieee80211_can_scan(local, sdata)) {
 640                 /* wait for the work to finish/time out */
 641                 rcu_assign_pointer(local->scan_req, req);
 642                 rcu_assign_pointer(local->scan_sdata, sdata);
 643                 return 0;
 644         }
 645
 646  again:
 647         if (hw_scan) {
 648                 u8 *ies;
 649
 650                 local->hw_scan_ies_bufsize = local->scan_ies_len + req->ie_len;
 651
 652                 if (ieee80211_hw_check(&local->hw, SINGLE_SCAN_ON_ALL_BANDS)) {
 653                         int i, n_bands = 0;
 654                         u8 bands_counted = 0;
 655
 656                         for (i = 0; i < req->n_channels; i++) {
 657                                 if (bands_counted & BIT(req->channels[i]->band))
 658                                         continue;
 659                                 bands_counted |= BIT(req->channels[i]->band);
 660                                 n_bands++;
 661                         }
 662
 663                         local->hw_scan_ies_bufsize *= n_bands;
 664                 }
 665
 666                 local->hw_scan_req = kmalloc(
 667                                 sizeof(*local->hw_scan_req) +
 668                                 req->n_channels * sizeof(req->channels[0]) +
 669                                 local->hw_scan_ies_bufsize, GFP_KERNEL);
 670                 if (!local->hw_scan_req)
 671                         return -ENOMEM;
 672
 673                 local->hw_scan_req->req.ssids = req->ssids;
 674                 local->hw_scan_req->req.n_ssids = req->n_ssids;
 675                 ies = (u8 *)local->hw_scan_req +
 676                         sizeof(*local->hw_scan_req) +
 677                         req->n_channels * sizeof(req->channels[0]);
 678                 local->hw_scan_req->req.ie = ies;
 679                 local->hw_scan_req->req.flags = req->flags;
 680                 eth_broadcast_addr(local->hw_scan_req->req.bssid);
 681                 local->hw_scan_req->req.duration = req->duration;
 682                 local->hw_scan_req->req.duration_mandatory =
 683                         req->duration_mandatory;
 684
 685                 local->hw_scan_band = 0;
 686
 687                 /*
 688                  * After allocating local->hw_scan_req, we must
 689                  * go through until ieee80211_prep_hw_scan(), so
 690                  * anything that might be changed here and leave
 691                  * this function early must not go after this
 692                  * allocation.
 693                  */
 694         }
 695
 696         rcu_assign_pointer(local->scan_req, req);
 697         rcu_assign_pointer(local->scan_sdata, sdata);
 698
 699         if (req->flags & NL80211_SCAN_FLAG_RANDOM_ADDR)
 700                 get_random_mask_addr(local->scan_addr,
 701                                      req->mac_addr,
 702                                      req->mac_addr_mask);
 703         else
 704                 memcpy(local->scan_addr, sdata->vif.addr, ETH_ALEN);
 705
 706         if (hw_scan) {
 707                 __set_bit(SCAN_HW_SCANNING, &local->scanning);
 708         } else if ((req->n_channels == 1) &&
 709                    (req->channels[0] == local->_oper_chandef.chan)) {
 710                 /*
 711                  * If we are scanning only on the operating channel
 712                  * then we do not need to stop normal activities
 713                  */
 714                 unsigned long next_delay;
 715
 716                 __set_bit(SCAN_ONCHANNEL_SCANNING, &local->scanning);
 717
 718                 ieee80211_recalc_idle(local);
 719
 720                 /* Notify driver scan is starting, keep order of operations
 721                  * same as normal software scan, in case that matters. */
 722                 drv_sw_scan_start(local, sdata, local->scan_addr);
 723
 724                 ieee80211_configure_filter(local); /* accept probe-responses */
 725
 726                 /* We need to ensure power level is at max for scanning. */
 727                 ieee80211_hw_config(local, 0);
 728
 729                 if ((req->channels[0]->flags & (IEEE80211_CHAN_NO_IR |
 730                                                 IEEE80211_CHAN_RADAR)) ||
 731                     !req->n_ssids) {
 732                         next_delay = IEEE80211_PASSIVE_CHANNEL_TIME;
 733                 } else {
 734                         ieee80211_scan_state_send_probe(local, &next_delay);
 735                         next_delay = IEEE80211_CHANNEL_TIME;
 736                 }
 737
 738                 /* Now, just wait a bit and we are all done! */
 739                 ieee80211_queue_delayed_work(&local->hw, &local->scan_work,
 740                                              next_delay);
 741                 return 0;
 742         } else {
 743                 /* Do normal software scan */
 744                 __set_bit(SCAN_SW_SCANNING, &local->scanning);
 745         }
 746
 747         ieee80211_recalc_idle(local);
 748
 749         if (hw_scan) {
 750                 WARN_ON(!ieee80211_prep_hw_scan(local));
 751                 rc = drv_hw_scan(local, sdata, local->hw_scan_req);
 752         } else {
 753                 rc = ieee80211_start_sw_scan(local, sdata);
 754         }
 755
 756         if (rc) {
 757                 kfree(local->hw_scan_req);
 758                 local->hw_scan_req = NULL;
 759                 local->scanning = 0;
 760
 761                 ieee80211_recalc_idle(local);
 762
 763                 local->scan_req = NULL;
 764                 RCU_INIT_POINTER(local->scan_sdata, NULL);
 765         }
 766
 767         if (hw_scan && rc == 1) {
 768                 /*
 769                  * we can't fall back to software for P2P-GO
 770                  * as it must update NoA etc.
 771                  */
 772                 if (ieee80211_vif_type_p2p(&sdata->vif) ==
 773                                 NL80211_IFTYPE_P2P_GO)
 774                         return -EOPNOTSUPP;
 775                 hw_scan = false;
 776                 goto again;
 777         }
 778
 779         return rc;
 780 }
 781
 782 static unsigned long
 783 ieee80211_scan_get_channel_time(struct ieee80211_channel *chan)
 784 {
 785         /*
 786          * TODO: channel switching also consumes quite some time,
 787          * add that delay as well to get a better estimation
 788          */
 789         if (chan->flags & (IEEE80211_CHAN_NO_IR | IEEE80211_CHAN_RADAR))
 790                 return IEEE80211_PASSIVE_CHANNEL_TIME;
 791         return IEEE80211_PROBE_DELAY + IEEE80211_CHANNEL_TIME;
 792 }
 793
 794 static void ieee80211_scan_state_decision(struct ieee80211_local *local,
 795                                           unsigned long *next_delay)
 796 {
 797         bool associated = false;
 798         bool tx_empty = true;
 799         bool bad_latency;
 800         struct ieee80211_sub_if_data *sdata;
 801         struct ieee80211_channel *next_chan;
 802         enum mac80211_scan_state next_scan_state;
 803         struct cfg80211_scan_request *scan_req;
 804
 805         /*
 806          * check if at least one STA interface is associated,
 807          * check if at least one STA interface has pending tx frames
 808          * and grab the lowest used beacon interval
 809          */
 810         mutex_lock(&local->iflist_mtx);
 811         list_for_each_entry(sdata, &local->interfaces, list) {
 812                 if (!ieee80211_sdata_running(sdata))
 813                         continue;
 814
 815                 if (sdata->vif.type == NL80211_IFTYPE_STATION) {
 816                         if (sdata->u.mgd.associated) {
 817                                 associated = true;
 818
 819                                 if (!qdisc_all_tx_empty(sdata->dev)) {
 820                                         tx_empty = false;
 821                                         break;
 822                                 }
 823                         }
 824                 }
 825         }
 826         mutex_unlock(&local->iflist_mtx);
 827
 828         scan_req = rcu_dereference_protected(local->scan_req,
 829                                              lockdep_is_held(&local->mtx));
 830
 831         next_chan = scan_req->channels[local->scan_channel_idx];
 832
 833         /*
 834          * we're currently scanning a different channel, let's
 835          * see if we can scan another channel without interfering
 836          * with the current traffic situation.
 837          *
 838          * Keep good latency, do not stay off-channel more than 125 ms.
 839          */
 840
 841         bad_latency = time_after(jiffies +
 842                                  ieee80211_scan_get_channel_time(next_chan),
 843                                  local->leave_oper_channel_time + HZ / 8);
 844
 845         if (associated && !tx_empty) {
 846                 if (scan_req->flags & NL80211_SCAN_FLAG_LOW_PRIORITY)
 847                         next_scan_state = SCAN_ABORT;
 848                 else
 849                         next_scan_state = SCAN_SUSPEND;
 850         } else if (associated && bad_latency) {
 851                 next_scan_state = SCAN_SUSPEND;
 852         } else {
 853                 next_scan_state = SCAN_SET_CHANNEL;
 854         }
 855
 856         local->next_scan_state = next_scan_state;
 857
 858         *next_delay = 0;
 859 }
 860
 861 static void ieee80211_scan_state_set_channel(struct ieee80211_local *local,
 862                                              unsigned long *next_delay)
 863 {
 864         int skip;
 865         struct ieee80211_channel *chan;
 866         enum nl80211_bss_scan_width oper_scan_width;
 867         struct cfg80211_scan_request *scan_req;
 868
 869         scan_req = rcu_dereference_protected(local->scan_req,
 870                                              lockdep_is_held(&local->mtx));
 871
 872         skip = 0;
 873         chan = scan_req->channels[local->scan_channel_idx];
 874
 875         local->scan_chandef.chan = chan;
 876         local->scan_chandef.center_freq1 = chan->center_freq;
 877         local->scan_chandef.center_freq2 = 0;
 878         switch (scan_req->scan_width) {
 879         case NL80211_BSS_CHAN_WIDTH_5:
 880                 local->scan_chandef.width = NL80211_CHAN_WIDTH_5;
 881                 break;
 882         case NL80211_BSS_CHAN_WIDTH_10:
 883                 local->scan_chandef.width = NL80211_CHAN_WIDTH_10;
 884                 break;
 885         case NL80211_BSS_CHAN_WIDTH_20:
 886                 /* If scanning on oper channel, use whatever channel-type
 887                  * is currently in use.
 888                  */
 889                 oper_scan_width = cfg80211_chandef_to_scan_width(
 890                                         &local->_oper_chandef);
 891                 if (chan == local->_oper_chandef.chan &&
 892                     oper_scan_width == scan_req->scan_width)
 893                         local->scan_chandef = local->_oper_chandef;
 894                 else
 895                         local->scan_chandef.width = NL80211_CHAN_WIDTH_20_NOHT;
 896                 break;
 897         }
 898
 899         if (ieee80211_hw_config(local, IEEE80211_CONF_CHANGE_CHANNEL))
 900                 skip = 1;
 901
 902         /* advance state machine to next channel/band */
 903         local->scan_channel_idx++;
 904
 905         if (skip) {
 906                 /* if we skip this channel return to the decision state */
 907                 local->next_scan_state = SCAN_DECISION;
 908                 return;
 909         }
 910
 911         /*
 912          * Probe delay is used to update the NAV, cf. 11.1.3.2.2
 913          * (which unfortunately doesn't say _why_ step a) is done,
 914          * but it waits for the probe delay or until a frame is
 915          * received - and the received frame would update the NAV).
 916          * For now, we do not support waiting until a frame is
 917          * received.
 918          *
 919          * In any case, it is not necessary for a passive scan.
 920          */
 921         if ((chan->flags & (IEEE80211_CHAN_NO_IR | IEEE80211_CHAN_RADAR)) ||
 922             !scan_req->n_ssids) {
 923                 *next_delay = IEEE80211_PASSIVE_CHANNEL_TIME;
 924                 local->next_scan_state = SCAN_DECISION;
 925                 return;
 926         }
 927
 928         /* active scan, send probes */
 929         *next_delay = IEEE80211_PROBE_DELAY;
 930         local->next_scan_state = SCAN_SEND_PROBE;
 931 }
 932
 933 static void ieee80211_scan_state_suspend(struct ieee80211_local *local,
 934                                          unsigned long *next_delay)
 935 {
 936         /* switch back to the operating channel */
 937         local->scan_chandef.chan = NULL;
 938         ieee80211_hw_config(local, IEEE80211_CONF_CHANGE_CHANNEL);
 939
 940         /* disable PS */
 941         ieee80211_offchannel_return(local);
 942
 943         *next_delay = HZ / 5;
 944         /* afterwards, resume scan & go to next channel */
 945         local->next_scan_state = SCAN_RESUME;
 946 }
 947
 948 static void ieee80211_scan_state_resume(struct ieee80211_local *local,
 949                                         unsigned long *next_delay)
 950 {
 951         ieee80211_offchannel_stop_vifs(local);
 952
 953         if (local->ops->flush) {
 954                 ieee80211_flush_queues(local, NULL, false);
 955                 *next_delay = 0;
 956         } else
 957                 *next_delay = HZ / 10;
 958
 959         /* remember when we left the operating channel */
 960         local->leave_oper_channel_time = jiffies;
 961
 962         /* advance to the next channel to be scanned */
 963         local->next_scan_state = SCAN_SET_CHANNEL;
 964 }
 965
 966 void ieee80211_scan_work(struct work_struct *work)
 967 {
 968         struct ieee80211_local *local =
 969                 container_of(work, struct ieee80211_local, scan_work.work);
 970         struct ieee80211_sub_if_data *sdata;
 971         struct cfg80211_scan_request *scan_req;
 972         unsigned long next_delay = 0;
 973         bool aborted;
 974
 975         mutex_lock(&local->mtx);
 976
 977         if (!ieee80211_can_run_worker(local)) {
 978                 aborted = true;
 979                 goto out_complete;
 980         }
 981
 982         sdata = rcu_dereference_protected(local->scan_sdata,
 983                                           lockdep_is_held(&local->mtx));
 984         scan_req = rcu_dereference_protected(local->scan_req,
 985                                              lockdep_is_held(&local->mtx));
 986
 987         /* When scanning on-channel, the first-callback means completed. */
 988         if (test_bit(SCAN_ONCHANNEL_SCANNING, &local->scanning)) {
 989                 aborted = test_and_clear_bit(SCAN_ABORTED, &local->scanning);
 990                 goto out_complete;
 991         }
 992
 993         if (test_and_clear_bit(SCAN_COMPLETED, &local->scanning)) {
 994                 aborted = test_and_clear_bit(SCAN_ABORTED, &local->scanning);
 995                 goto out_complete;
 996         }
 997
 998         if (!sdata || !scan_req)
 999                 goto out;
1000
1001         if (!local->scanning) {
1002                 int rc;
1003
1004                 RCU_INIT_POINTER(local->scan_req, NULL);
1005                 RCU_INIT_POINTER(local->scan_sdata, NULL);
1006
1007                 rc = __ieee80211_start_scan(sdata, scan_req);
1008                 if (rc) {
1009                         /* need to complete scan in cfg80211 */
1010                         rcu_assign_pointer(local->scan_req, scan_req);
1011                         aborted = true;
1012                         goto out_complete;
1013                 } else
1014                         goto out;
1015         }
1016
1017         /*
1018          * as long as no delay is required advance immediately
1019          * without scheduling a new work
1020          */
1021         do {
1022                 if (!ieee80211_sdata_running(sdata)) {
1023                         aborted = true;
1024                         goto out_complete;
1025                 }
1026
1027                 switch (local->next_scan_state) {
1028                 case SCAN_DECISION:
1029                         /* if no more bands/channels left, complete scan */
1030                         if (local->scan_channel_idx >= scan_req->n_channels) {
1031                                 aborted = false;
1032                                 goto out_complete;
1033                         }
1034                         ieee80211_scan_state_decision(local, &next_delay);
1035                         break;
1036                 case SCAN_SET_CHANNEL:
1037                         ieee80211_scan_state_set_channel(local, &next_delay);
1038                         break;
1039                 case SCAN_SEND_PROBE:
1040                         ieee80211_scan_state_send_probe(local, &next_delay);
1041                         break;
1042                 case SCAN_SUSPEND:
1043                         ieee80211_scan_state_suspend(local, &next_delay);
1044                         break;
1045                 case SCAN_RESUME:
1046                         ieee80211_scan_state_resume(local, &next_delay);
1047                         break;
1048                 case SCAN_ABORT:
1049                         aborted = true;
1050                         goto out_complete;
1051                 }
1052         } while (next_delay == 0);
1053
1054         ieee80211_queue_delayed_work(&local->hw, &local->scan_work, next_delay);
1055         goto out;
1056
1057 out_complete:
1058         __ieee80211_scan_completed(&local->hw, aborted);
1059 out:
1060         mutex_unlock(&local->mtx);
1061 }
1062
1063 int ieee80211_request_scan(struct ieee80211_sub_if_data *sdata,
1064                            struct cfg80211_scan_request *req)
1065 {
1066         int res;
1067
1068         mutex_lock(&sdata->local->mtx);
1069         res = __ieee80211_start_scan(sdata, req);
1070         mutex_unlock(&sdata->local->mtx);
1071
1072         return res;
1073 }
1074
1075 int ieee80211_request_ibss_scan(struct ieee80211_sub_if_data *sdata,
1076                                 const u8 *ssid, u8 ssid_len,
1077                                 struct ieee80211_channel **channels,
1078                                 unsigned int n_channels,
1079                                 enum nl80211_bss_scan_width scan_width)
1080 {
1081         struct ieee80211_local *local = sdata->local;
1082         int ret = -EBUSY, i, n_ch = 0;
1083         enum nl80211_band band;
1084
1085         mutex_lock(&local->mtx);
1086
1087         /* busy scanning */
1088         if (local->scan_req)
1089                 goto unlock;
1090
1091         /* fill internal scan request */
1092         if (!channels) {
1093                 int max_n;
1094
1095                 for (band = 0; band < NUM_NL80211_BANDS; band++) {
1096                         if (!local->hw.wiphy->bands[band])
1097                                 continue;
1098
1099                         max_n = local->hw.wiphy->bands[band]->n_channels;
1100                         for (i = 0; i < max_n; i++) {
1101                                 struct ieee80211_channel *tmp_ch =
1102                                     &local->hw.wiphy->bands[band]->channels[i];
1103
1104                                 if (tmp_ch->flags & (IEEE80211_CHAN_NO_IR |
1105                                                      IEEE80211_CHAN_DISABLED))
1106                                         continue;
1107
1108                                 local->int_scan_req->channels[n_ch] = tmp_ch;
1109                                 n_ch++;
1110                         }
1111                 }
1112
1113                 if (WARN_ON_ONCE(n_ch == 0))
1114                         goto unlock;
1115
1116                 local->int_scan_req->n_channels = n_ch;
1117         } else {
1118                 for (i = 0; i < n_channels; i++) {
1119                         if (channels[i]->flags & (IEEE80211_CHAN_NO_IR |
1120                                                   IEEE80211_CHAN_DISABLED))
1121                                 continue;
1122
1123                         local->int_scan_req->channels[n_ch] = channels[i];
1124                         n_ch++;
1125                 }
1126
1127                 if (WARN_ON_ONCE(n_ch == 0))
1128                         goto unlock;
1129
1130                 local->int_scan_req->n_channels = n_ch;
1131         }
1132
1133         local->int_scan_req->ssids = &local->scan_ssid;
1134         local->int_scan_req->n_ssids = 1;
1135         local->int_scan_req->scan_width = scan_width;
1136         memcpy(local->int_scan_req->ssids[0].ssid, ssid, IEEE80211_MAX_SSID_LEN);
1137         local->int_scan_req->ssids[0].ssid_len = ssid_len;
1138
1139         ret = __ieee80211_start_scan(sdata, sdata->local->int_scan_req);
1140  unlock:
1141         mutex_unlock(&local->mtx);
1142         return ret;
1143 }
1144
1145 /*
1146  * Only call this function when a scan can't be queued -- under RTNL.
1147  */
1148 void ieee80211_scan_cancel(struct ieee80211_local *local)
1149 {
1150         /*
1151          * We are canceling software scan, or deferred scan that was not
1152          * yet really started (see __ieee80211_start_scan ).
1153          *
1154          * Regarding hardware scan:
1155          * - we can not call  __ieee80211_scan_completed() as when
1156          *   SCAN_HW_SCANNING bit is set this function change
1157          *   local->hw_scan_req to operate on 5G band, what race with
1158          *   driver which can use local->hw_scan_req
1159          *
1160          * - we can not cancel scan_work since driver can schedule it
1161          *   by ieee80211_scan_completed(..., true) to finish scan
1162          *
1163          * Hence we only call the cancel_hw_scan() callback, but the low-level
1164          * driver is still responsible for calling ieee80211_scan_completed()
1165          * after the scan was completed/aborted.
1166          */
1167
1168         mutex_lock(&local->mtx);
1169         if (!local->scan_req)
1170                 goto out;
1171
1172         /*
1173          * We have a scan running and the driver already reported completion,
1174          * but the worker hasn't run yet or is stuck on the mutex - mark it as
1175          * cancelled.
1176          */
1177         if (test_bit(SCAN_HW_SCANNING, &local->scanning) &&
1178             test_bit(SCAN_COMPLETED, &local->scanning)) {
1179                 set_bit(SCAN_HW_CANCELLED, &local->scanning);
1180                 goto out;
1181         }
1182
1183         if (test_bit(SCAN_HW_SCANNING, &local->scanning)) {
1184                 /*
1185                  * Make sure that __ieee80211_scan_completed doesn't trigger a
1186                  * scan on another band.
1187                  */
1188                 set_bit(SCAN_HW_CANCELLED, &local->scanning);
1189                 if (local->ops->cancel_hw_scan)
1190                         drv_cancel_hw_scan(local,
1191                                 rcu_dereference_protected(local->scan_sdata,
1192                                                 lockdep_is_held(&local->mtx)));
1193                 goto out;
1194         }
1195
1196         /*
1197          * If the work is currently running, it must be blocked on
1198          * the mutex, but we'll set scan_sdata = NULL and it'll
1199          * simply exit once it acquires the mutex.
1200          */
1201         cancel_delayed_work(&local->scan_work);
1202         /* and clean up */
1203         memset(&local->scan_info, 0, sizeof(local->scan_info));
1204         __ieee80211_scan_completed(&local->hw, true);
1205 out:
1206         mutex_unlock(&local->mtx);
1207 }
1208
1209 int __ieee80211_request_sched_scan_start(struct ieee80211_sub_if_data *sdata,
1210                                         struct cfg80211_sched_scan_request *req)
1211 {
1212         struct ieee80211_local *local = sdata->local;
1213         struct ieee80211_scan_ies sched_scan_ies = {};
1214         struct cfg80211_chan_def chandef;
1215         int ret, i, iebufsz, num_bands = 0;
1216         u32 rate_masks[NUM_NL80211_BANDS] = {};
1217         u8 bands_used = 0;
1218         u8 *ie;
1219         u32 flags = 0;
1220
1221         iebufsz = local->scan_ies_len + req->ie_len;
1222
1223         lockdep_assert_held(&local->mtx);
1224
1225         if (!local->ops->sched_scan_start)
1226                 return -ENOTSUPP;
1227
1228         for (i = 0; i < NUM_NL80211_BANDS; i++) {
1229                 if (local->hw.wiphy->bands[i]) {
1230                         bands_used |= BIT(i);
1231                         rate_masks[i] = (u32) -1;
1232                         num_bands++;
1233                 }
1234         }
1235
1236         if (req->flags & NL80211_SCAN_FLAG_MIN_PREQ_CONTENT)
1237                 flags |= IEEE80211_PROBE_FLAG_MIN_CONTENT;
1238
1239         ie = kcalloc(iebufsz, num_bands, GFP_KERNEL);
1240         if (!ie) {
1241                 ret = -ENOMEM;
1242                 goto out;
1243         }
1244
1245         ieee80211_prepare_scan_chandef(&chandef, req->scan_width);
1246
1247         ieee80211_build_preq_ies(local, ie, num_bands * iebufsz,
1248                                  &sched_scan_ies, req->ie,
1249                                  req->ie_len, bands_used, rate_masks, &chandef,
1250                                  flags);
1251
1252         ret = drv_sched_scan_start(local, sdata, req, &sched_scan_ies);
1253         if (ret == 0) {
1254                 rcu_assign_pointer(local->sched_scan_sdata, sdata);
1255                 rcu_assign_pointer(local->sched_scan_req, req);
1256         }
1257
1258         kfree(ie);
1259
1260 out:
1261         if (ret) {
1262                 /* Clean in case of failure after HW restart or upon resume. */
1263                 RCU_INIT_POINTER(local->sched_scan_sdata, NULL);
1264                 RCU_INIT_POINTER(local->sched_scan_req, NULL);
1265         }
1266
1267         return ret;
1268 }
1269
1270 int ieee80211_request_sched_scan_start(struct ieee80211_sub_if_data *sdata,
1271                                        struct cfg80211_sched_scan_request *req)
1272 {
1273         struct ieee80211_local *local = sdata->local;
1274         int ret;
1275
1276         mutex_lock(&local->mtx);
1277
1278         if (rcu_access_pointer(local->sched_scan_sdata)) {
1279                 mutex_unlock(&local->mtx);
1280                 return -EBUSY;
1281         }
1282
1283         ret = __ieee80211_request_sched_scan_start(sdata, req);
1284
1285         mutex_unlock(&local->mtx);
1286         return ret;
1287 }
1288
1289 int ieee80211_request_sched_scan_stop(struct ieee80211_local *local)
1290 {
1291         struct ieee80211_sub_if_data *sched_scan_sdata;
1292         int ret = -ENOENT;
1293
1294         mutex_lock(&local->mtx);
1295
1296         if (!local->ops->sched_scan_stop) {
1297                 ret = -ENOTSUPP;
1298                 goto out;
1299         }
1300
1301         /* We don't want to restart sched scan anymore. */
1302         RCU_INIT_POINTER(local->sched_scan_req, NULL);
1303
1304         sched_scan_sdata = rcu_dereference_protected(local->sched_scan_sdata,
1305                                                 lockdep_is_held(&local->mtx));
1306         if (sched_scan_sdata) {
1307                 ret = drv_sched_scan_stop(local, sched_scan_sdata);
1308                 if (!ret)
1309                         RCU_INIT_POINTER(local->sched_scan_sdata, NULL);
1310         }
1311 out:
1312         mutex_unlock(&local->mtx);
1313
1314         return ret;
1315 }
1316
1317 void ieee80211_sched_scan_results(struct ieee80211_hw *hw)
1318 {
1319         struct ieee80211_local *local = hw_to_local(hw);
1320
1321         trace_api_sched_scan_results(local);
1322
1323         cfg80211_sched_scan_results(hw->wiphy, 0);
1324 }
1325 EXPORT_SYMBOL(ieee80211_sched_scan_results);
1326
1327 void ieee80211_sched_scan_end(struct ieee80211_local *local)
1328 {
1329         mutex_lock(&local->mtx);
1330
1331         if (!rcu_access_pointer(local->sched_scan_sdata)) {
1332                 mutex_unlock(&local->mtx);
1333                 return;
1334         }
1335
1336         RCU_INIT_POINTER(local->sched_scan_sdata, NULL);
1337
1338         /* If sched scan was aborted by the driver. */
1339         RCU_INIT_POINTER(local->sched_scan_req, NULL);
1340
1341         mutex_unlock(&local->mtx);
1342
1343         cfg80211_sched_scan_stopped(local->hw.wiphy, 0);
1344 }
1345
1346 void ieee80211_sched_scan_stopped_work(struct work_struct *work)
1347 {
1348         struct ieee80211_local *local =
1349                 container_of(work, struct ieee80211_local,
1350                              sched_scan_stopped_work);
1351
1352         ieee80211_sched_scan_end(local);
1353 }
1354
1355 void ieee80211_sched_scan_stopped(struct ieee80211_hw *hw)
1356 {
1357         struct ieee80211_local *local = hw_to_local(hw);
1358
1359         trace_api_sched_scan_stopped(local);
1360
1361         /*
1362          * this shouldn't really happen, so for simplicity
1363          * simply ignore it, and let mac80211 reconfigure
1364          * the sched scan later on.
1365          */
1366         if (local->in_reconfig)
1367                 return;
1368
1369         schedule_work(&local->sched_scan_stopped_work);
1370 }
1371 EXPORT_SYMBOL(ieee80211_sched_scan_stopped);