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