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