net/mac80211/scan.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  * Scanning implementation
   4  *
   5  * Copyright 2003, Jouni Malinen <jkmaline@cc.hut.fi>
   6  * Copyright 2004, Instant802 Networks, Inc.
   7  * Copyright 2005, Devicescape Software, Inc.
   8  * Copyright 2006-2007  Jiri Benc <jbenc@suse.cz>
   9  * Copyright 2007, Michael Wu <flamingice@sourmilk.net>
  10  * Copyright 2013-2015  Intel Mobile Communications GmbH
  11  * Copyright 2016-2017  Intel Deutschland GmbH
  12  * Copyright (C) 2018-2020 Intel Corporation
  13  */
  14
  15 #include <linux/if_arp.h>
  16 #include <linux/etherdevice.h>
  17 #include <linux/rtnetlink.h>
  18 #include <net/sch_generic.h>
  19 #include <linux/slab.h>
  20 #include <linux/export.h>
  21 #include <linux/random.h>
  22 #include <net/mac80211.h>
  23
  24 #include "ieee80211_i.h"
  25 #include "driver-ops.h"
  26 #include "mesh.h"
  27
  28 #define IEEE80211_PROBE_DELAY (HZ / 33)
  29 #define IEEE80211_CHANNEL_TIME (HZ / 33)
  30 #define IEEE80211_PASSIVE_CHANNEL_TIME (HZ / 9)
  31
  32 void ieee80211_rx_bss_put(struct ieee80211_local *local,
  33                           struct ieee80211_bss *bss)
  34 {
  35         if (!bss)
  36                 return;
  37         cfg80211_put_bss(local->hw.wiphy,
  38                          container_of((void *)bss, struct cfg80211_bss, priv));
  39 }
  40
  41 static bool is_uapsd_supported(struct ieee802_11_elems *elems)
  42 {
  43         u8 qos_info;
  44
  45         if (elems->wmm_info && elems->wmm_info_len == 7
  46             && elems->wmm_info[5] == 1)
  47                 qos_info = elems->wmm_info[6];
  48         else if (elems->wmm_param && elems->wmm_param_len == 24
  49                  && elems->wmm_param[5] == 1)
  50                 qos_info = elems->wmm_param[6];
  51         else
  52                 /* no valid wmm information or parameter element found */
  53                 return false;
  54
  55         return qos_info & IEEE80211_WMM_IE_AP_QOSINFO_UAPSD;
  56 }
  57
  58 static void
  59 ieee80211_update_bss_from_elems(struct ieee80211_local *local,
  60                                 struct ieee80211_bss *bss,
  61                                 struct ieee802_11_elems *elems,
  62                                 struct ieee80211_rx_status *rx_status,
  63                                 bool beacon)
  64 {
  65         int clen, srlen;
  66
  67         if (beacon)
  68                 bss->device_ts_beacon = rx_status->device_timestamp;
  69         else
  70                 bss->device_ts_presp = rx_status->device_timestamp;
  71
  72         if (elems->parse_error) {
  73                 if (beacon)
  74                         bss->corrupt_data |= IEEE80211_BSS_CORRUPT_BEACON;
  75                 else
  76                         bss->corrupt_data |= IEEE80211_BSS_CORRUPT_PROBE_RESP;
  77         } else {
  78                 if (beacon)
  79                         bss->corrupt_data &= ~IEEE80211_BSS_CORRUPT_BEACON;
  80                 else
  81                         bss->corrupt_data &= ~IEEE80211_BSS_CORRUPT_PROBE_RESP;
  82         }
  83
  84         /* save the ERP value so that it is available at association time */
  85         if (elems->erp_info && (!elems->parse_error ||
  86                                 !(bss->valid_data & IEEE80211_BSS_VALID_ERP))) {
  87                 bss->erp_value = elems->erp_info[0];
  88                 bss->has_erp_value = true;
  89                 if (!elems->parse_error)
  90                         bss->valid_data |= IEEE80211_BSS_VALID_ERP;
  91         }
  92
  93         /* replace old supported rates if we get new values */
  94         if (!elems->parse_error ||
  95             !(bss->valid_data & IEEE80211_BSS_VALID_RATES)) {
  96                 srlen = 0;
  97                 if (elems->supp_rates) {
  98                         clen = IEEE80211_MAX_SUPP_RATES;
  99                         if (clen > elems->supp_rates_len)
 100                                 clen = elems->supp_rates_len;
 101                         memcpy(bss->supp_rates, elems->supp_rates, clen);
 102                         srlen += clen;
 103                 }
 104                 if (elems->ext_supp_rates) {
 105                         clen = IEEE80211_MAX_SUPP_RATES - srlen;
 106                         if (clen > elems->ext_supp_rates_len)
 107                                 clen = elems->ext_supp_rates_len;
 108                         memcpy(bss->supp_rates + srlen, elems->ext_supp_rates,
 109                                clen);
 110                         srlen += clen;
 111                 }
 112                 if (srlen) {
 113                         bss->supp_rates_len = srlen;
 114                         if (!elems->parse_error)
 115                                 bss->valid_data |= IEEE80211_BSS_VALID_RATES;
 116                 }
 117         }
 118
 119         if (!elems->parse_error ||
 120             !(bss->valid_data & IEEE80211_BSS_VALID_WMM)) {
 121                 bss->wmm_used = elems->wmm_param || elems->wmm_info;
 122                 bss->uapsd_supported = is_uapsd_supported(elems);
 123                 if (!elems->parse_error)
 124                         bss->valid_data |= IEEE80211_BSS_VALID_WMM;
 125         }
 126
 127         if (beacon) {
 128                 struct ieee80211_supported_band *sband =
 129                         local->hw.wiphy->bands[rx_status->band];
 130                 if (!(rx_status->encoding == RX_ENC_HT) &&
 131                     !(rx_status->encoding == RX_ENC_VHT))
 132                         bss->beacon_rate =
 133                                 &sband->bitrates[rx_status->rate_idx];
 134         }
 135
 136         if (elems->vht_cap_elem)
 137                 bss->vht_cap_info =
 138                         le32_to_cpu(elems->vht_cap_elem->vht_cap_info);
 139         else
 140                 bss->vht_cap_info = 0;
 141 }
 142
 143 struct ieee80211_bss *
 144 ieee80211_bss_info_update(struct ieee80211_local *local,
 145                           struct ieee80211_rx_status *rx_status,
 146                           struct ieee80211_mgmt *mgmt, size_t len,
 147                           struct ieee80211_channel *channel)
 148 {
 149         bool beacon = ieee80211_is_beacon(mgmt->frame_control) ||
 150                       ieee80211_is_s1g_beacon(mgmt->frame_control);
 151         struct cfg80211_bss *cbss, *non_tx_cbss;
 152         struct ieee80211_bss *bss, *non_tx_bss;
 153         struct cfg80211_inform_bss bss_meta = {
 154                 .boottime_ns = rx_status->boottime_ns,
 155         };
 156         bool signal_valid;
 157         struct ieee80211_sub_if_data *scan_sdata;
 158         struct ieee802_11_elems elems;
 159         size_t baselen;
 160         u8 *elements;
 161
 162         if (rx_status->flag & RX_FLAG_NO_SIGNAL_VAL)
 163                 bss_meta.signal = 0; /* invalid signal indication */
 164         else if (ieee80211_hw_check(&local->hw, SIGNAL_DBM))
 165                 bss_meta.signal = rx_status->signal * 100;
 166         else if (ieee80211_hw_check(&local->hw, SIGNAL_UNSPEC))
 167                 bss_meta.signal = (rx_status->signal * 100) / local->hw.max_signal;
 168
 169         bss_meta.scan_width = NL80211_BSS_CHAN_WIDTH_20;
 170         if (rx_status->bw == RATE_INFO_BW_5)
 171                 bss_meta.scan_width = NL80211_BSS_CHAN_WIDTH_5;
 172         else if (rx_status->bw == RATE_INFO_BW_10)
 173                 bss_meta.scan_width = NL80211_BSS_CHAN_WIDTH_10;
 174
 175         bss_meta.chan = channel;
 176
 177         rcu_read_lock();
 178         scan_sdata = rcu_dereference(local->scan_sdata);
 179         if (scan_sdata && scan_sdata->vif.type == NL80211_IFTYPE_STATION &&
 180             scan_sdata->vif.bss_conf.assoc &&
 181             ieee80211_have_rx_timestamp(rx_status)) {
 182                 bss_meta.parent_tsf =
 183                         ieee80211_calculate_rx_timestamp(local, rx_status,
 184                                                          len + FCS_LEN, 24);
 185                 ether_addr_copy(bss_meta.parent_bssid,
 186                                 scan_sdata->vif.bss_conf.bssid);
 187         }
 188         rcu_read_unlock();
 189
 190         cbss = cfg80211_inform_bss_frame_data(local->hw.wiphy, &bss_meta,
 191                                               mgmt, len, GFP_ATOMIC);
 192         if (!cbss)
 193                 return NULL;
 194
 195         if (ieee80211_is_probe_resp(mgmt->frame_control)) {
 196                 elements = mgmt->u.probe_resp.variable;
 197                 baselen = offsetof(struct ieee80211_mgmt,
 198                                    u.probe_resp.variable);
 199         } else if (ieee80211_is_s1g_beacon(mgmt->frame_control)) {
 200                 struct ieee80211_ext *ext = (void *) mgmt;
 201
 202                 baselen = offsetof(struct ieee80211_ext, u.s1g_beacon.variable);
 203                 elements = ext->u.s1g_beacon.variable;
 204         } else {
 205                 baselen = offsetof(struct ieee80211_mgmt, u.beacon.variable);
 206                 elements = mgmt->u.beacon.variable;
 207         }
 208
 209         if (baselen > len)
 210                 return NULL;
 211
 212         ieee802_11_parse_elems(elements, len - baselen, false, &elems,
 213                                mgmt->bssid, cbss->bssid);
 214
 215         /* In case the signal is invalid update the status */
 216         signal_valid = channel == cbss->channel;
 217         if (!signal_valid)
 218                 rx_status->flag |= RX_FLAG_NO_SIGNAL_VAL;
 219
 220         bss = (void *)cbss->priv;
 221         ieee80211_update_bss_from_elems(local, bss, &elems, rx_status, beacon);
 222
 223         list_for_each_entry(non_tx_cbss, &cbss->nontrans_list, nontrans_list) {
 224                 non_tx_bss = (void *)non_tx_cbss->priv;
 225
 226                 ieee80211_update_bss_from_elems(local, non_tx_bss, &elems,
 227                                                 rx_status, beacon);
 228         }
 229
 230         return bss;
 231 }
 232
 233 static bool ieee80211_scan_accept_presp(struct ieee80211_sub_if_data *sdata,
 234                                         u32 scan_flags, const u8 *da)
 235 {
 236         if (!sdata)
 237                 return false;
 238         /* accept broadcast for OCE */
 239         if (scan_flags & NL80211_SCAN_FLAG_ACCEPT_BCAST_PROBE_RESP &&
 240             is_broadcast_ether_addr(da))
 241                 return true;
 242         if (scan_flags & NL80211_SCAN_FLAG_RANDOM_ADDR)
 243                 return true;
 244         return ether_addr_equal(da, sdata->vif.addr);
 245 }
 246
 247 void ieee80211_scan_rx(struct ieee80211_local *local, struct sk_buff *skb)
 248 {
 249         struct ieee80211_rx_status *rx_status = IEEE80211_SKB_RXCB(skb);
 250         struct ieee80211_sub_if_data *sdata1, *sdata2;
 251         struct ieee80211_mgmt *mgmt = (void *)skb->data;
 252         struct ieee80211_bss *bss;
 253         struct ieee80211_channel *channel;
 254         size_t min_hdr_len = offsetof(struct ieee80211_mgmt,
 255                                       u.probe_resp.variable);
 256
 257         if (!ieee80211_is_probe_resp(mgmt->frame_control) &&
 258             !ieee80211_is_beacon(mgmt->frame_control) &&
 259             !ieee80211_is_s1g_beacon(mgmt->frame_control))
 260                 return;
 261
 262         if (ieee80211_is_s1g_beacon(mgmt->frame_control)) {
 263                 if (ieee80211_is_s1g_short_beacon(mgmt->frame_control))
 264                         min_hdr_len = offsetof(struct ieee80211_ext,
 265                                                u.s1g_short_beacon.variable);
 266                 else
 267                         min_hdr_len = offsetof(struct ieee80211_ext,
 268                                                u.s1g_beacon);
 269         }
 270
 271         if (skb->len < min_hdr_len)
 272                 return;
 273
 274         sdata1 = rcu_dereference(local->scan_sdata);
 275         sdata2 = rcu_dereference(local->sched_scan_sdata);
 276
 277         if (likely(!sdata1 && !sdata2))
 278                 return;
 279
 280         if (ieee80211_is_probe_resp(mgmt->frame_control)) {
 281                 struct cfg80211_scan_request *scan_req;
 282                 struct cfg80211_sched_scan_request *sched_scan_req;
 283                 u32 scan_req_flags = 0, sched_scan_req_flags = 0;
 284
 285                 scan_req = rcu_dereference(local->scan_req);
 286                 sched_scan_req = rcu_dereference(local->sched_scan_req);
 287
 288                 if (scan_req)
 289                         scan_req_flags = scan_req->flags;
 290
 291                 if (sched_scan_req)
 292                         sched_scan_req_flags = sched_scan_req->flags;
 293
 294                 /* ignore ProbeResp to foreign address or non-bcast (OCE)
 295                  * unless scanning with randomised address
 296                  */
 297                 if (!ieee80211_scan_accept_presp(sdata1, scan_req_flags,
 298                                                  mgmt->da) &&
 299                     !ieee80211_scan_accept_presp(sdata2, sched_scan_req_flags,
 300                                                  mgmt->da))
 301                         return;
 302         }
 303
 304         channel = ieee80211_get_channel_khz(local->hw.wiphy,
 305                                         ieee80211_rx_status_to_khz(rx_status));
 306
 307         if (!channel || channel->flags & IEEE80211_CHAN_DISABLED)
 308                 return;
 309
 310         bss = ieee80211_bss_info_update(local, rx_status,
 311                                         mgmt, skb->len,
 312                                         channel);
 313         if (bss)
 314                 ieee80211_rx_bss_put(local, bss);
 315 }
 316
 317 static void
 318 ieee80211_prepare_scan_chandef(struct cfg80211_chan_def *chandef,
 319                                enum nl80211_bss_scan_width scan_width)
 320 {
 321         memset(chandef, 0, sizeof(*chandef));
 322         switch (scan_width) {
 323         case NL80211_BSS_CHAN_WIDTH_5:
 324                 chandef->width = NL80211_CHAN_WIDTH_5;
 325                 break;
 326         case NL80211_BSS_CHAN_WIDTH_10:
 327                 chandef->width = NL80211_CHAN_WIDTH_10;
 328                 break;
 329         default:
 330                 chandef->width = NL80211_CHAN_WIDTH_20_NOHT;
 331                 break;
 332         }
 333 }
 334
 335 /* return false if no more work */
 336 static bool ieee80211_prep_hw_scan(struct ieee80211_sub_if_data *sdata)
 337 {
 338         struct ieee80211_local *local = sdata->local;
 339         struct cfg80211_scan_request *req;
 340         struct cfg80211_chan_def chandef;
 341         u8 bands_used = 0;
 342         int i, ielen, n_chans;
 343         u32 flags = 0;
 344
 345         req = rcu_dereference_protected(local->scan_req,
 346                                         lockdep_is_held(&local->mtx));
 347
 348         if (test_bit(SCAN_HW_CANCELLED, &local->scanning))
 349                 return false;
 350
 351         if (ieee80211_hw_check(&local->hw, SINGLE_SCAN_ON_ALL_BANDS)) {
 352                 for (i = 0; i < req->n_channels; i++) {
 353                         local->hw_scan_req->req.channels[i] = req->channels[i];
 354                         bands_used |= BIT(req->channels[i]->band);
 355                 }
 356
 357                 n_chans = req->n_channels;
 358         } else {
 359                 do {
 360                         if (local->hw_scan_band == NUM_NL80211_BANDS)
 361                                 return false;
 362
 363                         n_chans = 0;
 364
 365                         for (i = 0; i < req->n_channels; i++) {
 366                                 if (req->channels[i]->band !=
 367                                     local->hw_scan_band)
 368                                         continue;
 369                                 local->hw_scan_req->req.channels[n_chans] =
 370                                                         req->channels[i];
 371                                 n_chans++;
 372                                 bands_used |= BIT(req->channels[i]->band);
 373                         }
 374
 375                         local->hw_scan_band++;
 376                 } while (!n_chans);
 377         }
 378
 379         local->hw_scan_req->req.n_channels = n_chans;
 380         ieee80211_prepare_scan_chandef(&chandef, req->scan_width);
 381
 382         if (req->flags & NL80211_SCAN_FLAG_MIN_PREQ_CONTENT)
 383                 flags |= IEEE80211_PROBE_FLAG_MIN_CONTENT;
 384
 385         ielen = ieee80211_build_preq_ies(sdata,
 386                                          (u8 *)local->hw_scan_req->req.ie,
 387                                          local->hw_scan_ies_bufsize,
 388                                          &local->hw_scan_req->ies,
 389                                          req->ie, req->ie_len,
 390                                          bands_used, req->rates, &chandef,
 391                                          flags);
 392         local->hw_scan_req->req.ie_len = ielen;
 393         local->hw_scan_req->req.no_cck = req->no_cck;
 394         ether_addr_copy(local->hw_scan_req->req.mac_addr, req->mac_addr);
 395         ether_addr_copy(local->hw_scan_req->req.mac_addr_mask,
 396                         req->mac_addr_mask);
 397         ether_addr_copy(local->hw_scan_req->req.bssid, req->bssid);
 398
 399         return true;
 400 }
 401
 402 static void __ieee80211_scan_completed(struct ieee80211_hw *hw, bool aborted)
 403 {
 404         struct ieee80211_local *local = hw_to_local(hw);
 405         bool hw_scan = test_bit(SCAN_HW_SCANNING, &local->scanning);
 406         bool was_scanning = local->scanning;
 407         struct cfg80211_scan_request *scan_req;
 408         struct ieee80211_sub_if_data *scan_sdata;
 409         struct ieee80211_sub_if_data *sdata;
 410
 411         lockdep_assert_held(&local->mtx);
 412
 413         /*
 414          * It's ok to abort a not-yet-running scan (that
 415          * we have one at all will be verified by checking
 416          * local->scan_req next), but not to complete it
 417          * successfully.
 418          */
 419         if (WARN_ON(!local->scanning && !aborted))
 420                 aborted = true;
 421
 422         if (WARN_ON(!local->scan_req))
 423                 return;
 424
 425         scan_sdata = rcu_dereference_protected(local->scan_sdata,
 426                                                lockdep_is_held(&local->mtx));
 427
 428         if (hw_scan && !aborted &&
 429             !ieee80211_hw_check(&local->hw, SINGLE_SCAN_ON_ALL_BANDS) &&
 430             ieee80211_prep_hw_scan(scan_sdata)) {
 431                 int rc;
 432
 433                 rc = drv_hw_scan(local,
 434                         rcu_dereference_protected(local->scan_sdata,
 435                                                   lockdep_is_held(&local->mtx)),
 436                         local->hw_scan_req);
 437
 438                 if (rc == 0)
 439                         return;
 440
 441                 /* HW scan failed and is going to be reported as aborted,
 442                  * so clear old scan info.
 443                  */
 444                 memset(&local->scan_info, 0, sizeof(local->scan_info));
 445                 aborted = true;
 446         }
 447
 448         kfree(local->hw_scan_req);
 449         local->hw_scan_req = NULL;
 450
 451         scan_req = rcu_dereference_protected(local->scan_req,
 452                                              lockdep_is_held(&local->mtx));
 453
 454         if (scan_req != local->int_scan_req) {
 455                 local->scan_info.aborted = aborted;
 456                 cfg80211_scan_done(scan_req, &local->scan_info);
 457         }
 458         RCU_INIT_POINTER(local->scan_req, NULL);
 459         RCU_INIT_POINTER(local->scan_sdata, NULL);
 460
 461         local->scanning = 0;
 462         local->scan_chandef.chan = NULL;
 463
 464         /* Set power back to normal operating levels. */
 465         ieee80211_hw_config(local, 0);
 466
 467         if (!hw_scan) {
 468                 ieee80211_configure_filter(local);
 469                 drv_sw_scan_complete(local, scan_sdata);
 470                 ieee80211_offchannel_return(local);
 471         }
 472
 473         ieee80211_recalc_idle(local);
 474
 475         ieee80211_mlme_notify_scan_completed(local);
 476         ieee80211_ibss_notify_scan_completed(local);
 477
 478         /* Requeue all the work that might have been ignored while
 479          * the scan was in progress; if there was none this will
 480          * just be a no-op for the particular interface.
 481          */
 482         list_for_each_entry_rcu(sdata, &local->interfaces, list) {
 483                 if (ieee80211_sdata_running(sdata))
 484                         ieee80211_queue_work(&sdata->local->hw, &sdata->work);
 485         }
 486
 487         if (was_scanning)
 488                 ieee80211_start_next_roc(local);
 489 }
 490
 491 void ieee80211_scan_completed(struct ieee80211_hw *hw,
 492                               struct cfg80211_scan_info *info)
 493 {
 494         struct ieee80211_local *local = hw_to_local(hw);
 495
 496         trace_api_scan_completed(local, info->aborted);
 497
 498         set_bit(SCAN_COMPLETED, &local->scanning);
 499         if (info->aborted)
 500                 set_bit(SCAN_ABORTED, &local->scanning);
 501
 502         memcpy(&local->scan_info, info, sizeof(*info));
 503
 504         ieee80211_queue_delayed_work(&local->hw, &local->scan_work, 0);
 505 }
 506 EXPORT_SYMBOL(ieee80211_scan_completed);
 507
 508 static int ieee80211_start_sw_scan(struct ieee80211_local *local,
 509                                    struct ieee80211_sub_if_data *sdata)
 510 {
 511         /* Software scan is not supported in multi-channel cases */
 512         if (local->use_chanctx)
 513                 return -EOPNOTSUPP;
 514
 515         /*
 516          * Hardware/driver doesn't support hw_scan, so use software
 517          * scanning instead. First send a nullfunc frame with power save
 518          * bit on so that AP will buffer the frames for us while we are not
 519          * listening, then send probe requests to each channel and wait for
 520          * the responses. After all channels are scanned, tune back to the
 521          * original channel and send a nullfunc frame with power save bit
 522          * off to trigger the AP to send us all the buffered frames.
 523          *
 524          * Note that while local->sw_scanning is true everything else but
 525          * nullfunc frames and probe requests will be dropped in
 526          * ieee80211_tx_h_check_assoc().
 527          */
 528         drv_sw_scan_start(local, sdata, local->scan_addr);
 529
 530         local->leave_oper_channel_time = jiffies;
 531         local->next_scan_state = SCAN_DECISION;
 532         local->scan_channel_idx = 0;
 533
 534         ieee80211_offchannel_stop_vifs(local);
 535
 536         /* ensure nullfunc is transmitted before leaving operating channel */
 537         ieee80211_flush_queues(local, NULL, false);
 538
 539         ieee80211_configure_filter(local);
 540
 541         /* We need to set power level at maximum rate for scanning. */
 542         ieee80211_hw_config(local, 0);
 543
 544         ieee80211_queue_delayed_work(&local->hw,
 545                                      &local->scan_work, 0);
 546
 547         return 0;
 548 }
 549
 550 static bool __ieee80211_can_leave_ch(struct ieee80211_sub_if_data *sdata)
 551 {
 552         struct ieee80211_local *local = sdata->local;
 553         struct ieee80211_sub_if_data *sdata_iter;
 554
 555         if (!ieee80211_is_radar_required(local))
 556                 return true;
 557
 558         if (!regulatory_pre_cac_allowed(local->hw.wiphy))
 559                 return false;
 560
 561         mutex_lock(&local->iflist_mtx);
 562         list_for_each_entry(sdata_iter, &local->interfaces, list) {
 563                 if (sdata_iter->wdev.cac_started) {
 564                         mutex_unlock(&local->iflist_mtx);
 565                         return false;
 566                 }
 567         }
 568         mutex_unlock(&local->iflist_mtx);
 569
 570         return true;
 571 }
 572
 573 static bool ieee80211_can_scan(struct ieee80211_local *local,
 574                                struct ieee80211_sub_if_data *sdata)
 575 {
 576         if (!__ieee80211_can_leave_ch(sdata))
 577                 return false;
 578
 579         if (!list_empty(&local->roc_list))
 580                 return false;
 581
 582         if (sdata->vif.type == NL80211_IFTYPE_STATION &&
 583             sdata->u.mgd.flags & IEEE80211_STA_CONNECTION_POLL)
 584                 return false;
 585
 586         return true;
 587 }
 588
 589 void ieee80211_run_deferred_scan(struct ieee80211_local *local)
 590 {
 591         lockdep_assert_held(&local->mtx);
 592
 593         if (!local->scan_req || local->scanning)
 594                 return;
 595
 596         if (!ieee80211_can_scan(local,
 597                                 rcu_dereference_protected(
 598                                         local->scan_sdata,
 599                                         lockdep_is_held(&local->mtx))))
 600                 return;
 601
 602         ieee80211_queue_delayed_work(&local->hw, &local->scan_work,
 603                                      round_jiffies_relative(0));
 604 }
 605
 606 static void ieee80211_send_scan_probe_req(struct ieee80211_sub_if_data *sdata,
 607                                           const u8 *src, const u8 *dst,
 608                                           const u8 *ssid, size_t ssid_len,
 609                                           const u8 *ie, size_t ie_len,
 610                                           u32 ratemask, u32 flags, u32 tx_flags,
 611                                           struct ieee80211_channel *channel)
 612 {
 613         struct sk_buff *skb;
 614
 615         skb = ieee80211_build_probe_req(sdata, src, dst, ratemask, channel,
 616                                         ssid, ssid_len,
 617                                         ie, ie_len, flags);
 618
 619         if (skb) {
 620                 if (flags & IEEE80211_PROBE_FLAG_RANDOM_SN) {
 621                         struct ieee80211_hdr *hdr = (void *)skb->data;
 622                         struct ieee80211_tx_info *info = IEEE80211_SKB_CB(skb);
 623                         u16 sn = get_random_u32();
 624
 625                         info->control.flags |= IEEE80211_TX_CTRL_NO_SEQNO;
 626                         hdr->seq_ctrl =
 627                                 cpu_to_le16(IEEE80211_SN_TO_SEQ(sn));
 628                 }
 629                 IEEE80211_SKB_CB(skb)->flags |= tx_flags;
 630                 ieee80211_tx_skb_tid_band(sdata, skb, 7, channel->band);
 631         }
 632 }
 633
 634 static void ieee80211_scan_state_send_probe(struct ieee80211_local *local,
 635                                             unsigned long *next_delay)
 636 {
 637         int i;
 638         struct ieee80211_sub_if_data *sdata;
 639         struct cfg80211_scan_request *scan_req;
 640         enum nl80211_band band = local->hw.conf.chandef.chan->band;
 641         u32 flags = 0, tx_flags;
 642
 643         scan_req = rcu_dereference_protected(local->scan_req,
 644                                              lockdep_is_held(&local->mtx));
 645
 646         tx_flags = IEEE80211_TX_INTFL_OFFCHAN_TX_OK;
 647         if (scan_req->no_cck)
 648                 tx_flags |= IEEE80211_TX_CTL_NO_CCK_RATE;
 649         if (scan_req->flags & NL80211_SCAN_FLAG_MIN_PREQ_CONTENT)
 650                 flags |= IEEE80211_PROBE_FLAG_MIN_CONTENT;
 651         if (scan_req->flags & NL80211_SCAN_FLAG_RANDOM_SN)
 652                 flags |= IEEE80211_PROBE_FLAG_RANDOM_SN;
 653
 654         sdata = rcu_dereference_protected(local->scan_sdata,
 655                                           lockdep_is_held(&local->mtx));
 656
 657         for (i = 0; i < scan_req->n_ssids; i++)
 658                 ieee80211_send_scan_probe_req(
 659                         sdata, local->scan_addr, scan_req->bssid,
 660                         scan_req->ssids[i].ssid, scan_req->ssids[i].ssid_len,
 661                         scan_req->ie, scan_req->ie_len,
 662                         scan_req->rates[band], flags,
 663                         tx_flags, local->hw.conf.chandef.chan);
 664
 665         /*
 666          * After sending probe requests, wait for probe responses
 667          * on the channel.
 668          */
 669         *next_delay = IEEE80211_CHANNEL_TIME;
 670         local->next_scan_state = SCAN_DECISION;
 671 }
 672
 673 static int __ieee80211_start_scan(struct ieee80211_sub_if_data *sdata,
 674                                   struct cfg80211_scan_request *req)
 675 {
 676         struct ieee80211_local *local = sdata->local;
 677         bool hw_scan = local->ops->hw_scan;
 678         int rc;
 679
 680         lockdep_assert_held(&local->mtx);
 681
 682         if (local->scan_req)
 683                 return -EBUSY;
 684
 685         if (!__ieee80211_can_leave_ch(sdata))
 686                 return -EBUSY;
 687
 688         if (!ieee80211_can_scan(local, sdata)) {
 689                 /* wait for the work to finish/time out */
 690                 rcu_assign_pointer(local->scan_req, req);
 691                 rcu_assign_pointer(local->scan_sdata, sdata);
 692                 return 0;
 693         }
 694
 695  again:
 696         if (hw_scan) {
 697                 u8 *ies;
 698
 699                 local->hw_scan_ies_bufsize = local->scan_ies_len + req->ie_len;
 700
 701                 if (ieee80211_hw_check(&local->hw, SINGLE_SCAN_ON_ALL_BANDS)) {
 702                         int i, n_bands = 0;
 703                         u8 bands_counted = 0;
 704
 705                         for (i = 0; i < req->n_channels; i++) {
 706                                 if (bands_counted & BIT(req->channels[i]->band))
 707                                         continue;
 708                                 bands_counted |= BIT(req->channels[i]->band);
 709                                 n_bands++;
 710                         }
 711
 712                         local->hw_scan_ies_bufsize *= n_bands;
 713                 }
 714
 715                 local->hw_scan_req = kmalloc(
 716                                 sizeof(*local->hw_scan_req) +
 717                                 req->n_channels * sizeof(req->channels[0]) +
 718                                 local->hw_scan_ies_bufsize, GFP_KERNEL);
 719                 if (!local->hw_scan_req)
 720                         return -ENOMEM;
 721
 722                 local->hw_scan_req->req.ssids = req->ssids;
 723                 local->hw_scan_req->req.n_ssids = req->n_ssids;
 724                 ies = (u8 *)local->hw_scan_req +
 725                         sizeof(*local->hw_scan_req) +
 726                         req->n_channels * sizeof(req->channels[0]);
 727                 local->hw_scan_req->req.ie = ies;
 728                 local->hw_scan_req->req.flags = req->flags;
 729                 eth_broadcast_addr(local->hw_scan_req->req.bssid);
 730                 local->hw_scan_req->req.duration = req->duration;
 731                 local->hw_scan_req->req.duration_mandatory =
 732                         req->duration_mandatory;
 733
 734                 local->hw_scan_band = 0;
 735                 local->hw_scan_req->req.n_6ghz_params = req->n_6ghz_params;
 736                 local->hw_scan_req->req.scan_6ghz_params =
 737                         req->scan_6ghz_params;
 738                 local->hw_scan_req->req.scan_6ghz = req->scan_6ghz;
 739
 740                 /*
 741                  * After allocating local->hw_scan_req, we must
 742                  * go through until ieee80211_prep_hw_scan(), so
 743                  * anything that might be changed here and leave
 744                  * this function early must not go after this
 745                  * allocation.
 746                  */
 747         }
 748
 749         rcu_assign_pointer(local->scan_req, req);
 750         rcu_assign_pointer(local->scan_sdata, sdata);
 751
 752         if (req->flags & NL80211_SCAN_FLAG_RANDOM_ADDR)
 753                 get_random_mask_addr(local->scan_addr,
 754                                      req->mac_addr,
 755                                      req->mac_addr_mask);
 756         else
 757                 memcpy(local->scan_addr, sdata->vif.addr, ETH_ALEN);
 758
 759         if (hw_scan) {
 760                 __set_bit(SCAN_HW_SCANNING, &local->scanning);
 761         } else if ((req->n_channels == 1) &&
 762                    (req->channels[0] == local->_oper_chandef.chan)) {
 763                 /*
 764                  * If we are scanning only on the operating channel
 765                  * then we do not need to stop normal activities
 766                  */
 767                 unsigned long next_delay;
 768
 769                 __set_bit(SCAN_ONCHANNEL_SCANNING, &local->scanning);
 770
 771                 ieee80211_recalc_idle(local);
 772
 773                 /* Notify driver scan is starting, keep order of operations
 774                  * same as normal software scan, in case that matters. */
 775                 drv_sw_scan_start(local, sdata, local->scan_addr);
 776
 777                 ieee80211_configure_filter(local); /* accept probe-responses */
 778
 779                 /* We need to ensure power level is at max for scanning. */
 780                 ieee80211_hw_config(local, 0);
 781
 782                 if ((req->channels[0]->flags & (IEEE80211_CHAN_NO_IR |
 783                                                 IEEE80211_CHAN_RADAR)) ||
 784                     !req->n_ssids) {
 785                         next_delay = IEEE80211_PASSIVE_CHANNEL_TIME;
 786                 } else {
 787                         ieee80211_scan_state_send_probe(local, &next_delay);
 788                         next_delay = IEEE80211_CHANNEL_TIME;
 789                 }
 790
 791                 /* Now, just wait a bit and we are all done! */
 792                 ieee80211_queue_delayed_work(&local->hw, &local->scan_work,
 793                                              next_delay);
 794                 return 0;
 795         } else {
 796                 /* Do normal software scan */
 797                 __set_bit(SCAN_SW_SCANNING, &local->scanning);
 798         }
 799
 800         ieee80211_recalc_idle(local);
 801
 802         if (hw_scan) {
 803                 WARN_ON(!ieee80211_prep_hw_scan(sdata));
 804                 rc = drv_hw_scan(local, sdata, local->hw_scan_req);
 805         } else {
 806                 rc = ieee80211_start_sw_scan(local, sdata);
 807         }
 808
 809         if (rc) {
 810                 kfree(local->hw_scan_req);
 811                 local->hw_scan_req = NULL;
 812                 local->scanning = 0;
 813
 814                 ieee80211_recalc_idle(local);
 815
 816                 local->scan_req = NULL;
 817                 RCU_INIT_POINTER(local->scan_sdata, NULL);
 818         }
 819
 820         if (hw_scan && rc == 1) {
 821                 /*
 822                  * we can't fall back to software for P2P-GO
 823                  * as it must update NoA etc.
 824                  */
 825                 if (ieee80211_vif_type_p2p(&sdata->vif) ==
 826                                 NL80211_IFTYPE_P2P_GO)
 827                         return -EOPNOTSUPP;
 828                 hw_scan = false;
 829                 goto again;
 830         }
 831
 832         return rc;
 833 }
 834
 835 static unsigned long
 836 ieee80211_scan_get_channel_time(struct ieee80211_channel *chan)
 837 {
 838         /*
 839          * TODO: channel switching also consumes quite some time,
 840          * add that delay as well to get a better estimation
 841          */
 842         if (chan->flags & (IEEE80211_CHAN_NO_IR | IEEE80211_CHAN_RADAR))
 843                 return IEEE80211_PASSIVE_CHANNEL_TIME;
 844         return IEEE80211_PROBE_DELAY + IEEE80211_CHANNEL_TIME;
 845 }
 846
 847 static void ieee80211_scan_state_decision(struct ieee80211_local *local,
 848                                           unsigned long *next_delay)
 849 {
 850         bool associated = false;
 851         bool tx_empty = true;
 852         bool bad_latency;
 853         struct ieee80211_sub_if_data *sdata;
 854         struct ieee80211_channel *next_chan;
 855         enum mac80211_scan_state next_scan_state;
 856         struct cfg80211_scan_request *scan_req;
 857
 858         /*
 859          * check if at least one STA interface is associated,
 860          * check if at least one STA interface has pending tx frames
 861          * and grab the lowest used beacon interval
 862          */
 863         mutex_lock(&local->iflist_mtx);
 864         list_for_each_entry(sdata, &local->interfaces, list) {
 865                 if (!ieee80211_sdata_running(sdata))
 866                         continue;
 867
 868                 if (sdata->vif.type == NL80211_IFTYPE_STATION) {
 869                         if (sdata->u.mgd.associated) {
 870                                 associated = true;
 871
 872                                 if (!qdisc_all_tx_empty(sdata->dev)) {
 873                                         tx_empty = false;
 874                                         break;
 875                                 }
 876                         }
 877                 }
 878         }
 879         mutex_unlock(&local->iflist_mtx);
 880
 881         scan_req = rcu_dereference_protected(local->scan_req,
 882                                              lockdep_is_held(&local->mtx));
 883
 884         next_chan = scan_req->channels[local->scan_channel_idx];
 885
 886         /*
 887          * we're currently scanning a different channel, let's
 888          * see if we can scan another channel without interfering
 889          * with the current traffic situation.
 890          *
 891          * Keep good latency, do not stay off-channel more than 125 ms.
 892          */
 893
 894         bad_latency = time_after(jiffies +
 895                                  ieee80211_scan_get_channel_time(next_chan),
 896                                  local->leave_oper_channel_time + HZ / 8);
 897
 898         if (associated && !tx_empty) {
 899                 if (scan_req->flags & NL80211_SCAN_FLAG_LOW_PRIORITY)
 900                         next_scan_state = SCAN_ABORT;
 901                 else
 902                         next_scan_state = SCAN_SUSPEND;
 903         } else if (associated && bad_latency) {
 904                 next_scan_state = SCAN_SUSPEND;
 905         } else {
 906                 next_scan_state = SCAN_SET_CHANNEL;
 907         }
 908
 909         local->next_scan_state = next_scan_state;
 910
 911         *next_delay = 0;
 912 }
 913
 914 static void ieee80211_scan_state_set_channel(struct ieee80211_local *local,
 915                                              unsigned long *next_delay)
 916 {
 917         int skip;
 918         struct ieee80211_channel *chan;
 919         enum nl80211_bss_scan_width oper_scan_width;
 920         struct cfg80211_scan_request *scan_req;
 921
 922         scan_req = rcu_dereference_protected(local->scan_req,
 923                                              lockdep_is_held(&local->mtx));
 924
 925         skip = 0;
 926         chan = scan_req->channels[local->scan_channel_idx];
 927
 928         local->scan_chandef.chan = chan;
 929         local->scan_chandef.center_freq1 = chan->center_freq;
 930         local->scan_chandef.freq1_offset = chan->freq_offset;
 931         local->scan_chandef.center_freq2 = 0;
 932
 933         /* For scanning on the S1G band, ignore scan_width (which is constant
 934          * across all channels) for now since channel width is specific to each
 935          * channel. Detect the required channel width here and likely revisit
 936          * later. Maybe scan_width could be used to build the channel scan list?
 937          */
 938         if (chan->band == NL80211_BAND_S1GHZ) {
 939                 local->scan_chandef.width = ieee80211_s1g_channel_width(chan);
 940                 goto set_channel;
 941         }
 942
 943         switch (scan_req->scan_width) {
 944         case NL80211_BSS_CHAN_WIDTH_5:
 945                 local->scan_chandef.width = NL80211_CHAN_WIDTH_5;
 946                 break;
 947         case NL80211_BSS_CHAN_WIDTH_10:
 948                 local->scan_chandef.width = NL80211_CHAN_WIDTH_10;
 949                 break;
 950         default:
 951         case NL80211_BSS_CHAN_WIDTH_20:
 952                 /* If scanning on oper channel, use whatever channel-type
 953                  * is currently in use.
 954                  */
 955                 oper_scan_width = cfg80211_chandef_to_scan_width(
 956                                         &local->_oper_chandef);
 957                 if (chan == local->_oper_chandef.chan &&
 958                     oper_scan_width == scan_req->scan_width)
 959                         local->scan_chandef = local->_oper_chandef;
 960                 else
 961                         local->scan_chandef.width = NL80211_CHAN_WIDTH_20_NOHT;
 962                 break;
 963         case NL80211_BSS_CHAN_WIDTH_1:
 964         case NL80211_BSS_CHAN_WIDTH_2:
 965                 /* shouldn't get here, S1G handled above */
 966                 WARN_ON(1);
 967                 break;
 968         }
 969
 970 set_channel:
 971         if (ieee80211_hw_config(local, IEEE80211_CONF_CHANGE_CHANNEL))
 972                 skip = 1;
 973
 974         /* advance state machine to next channel/band */
 975         local->scan_channel_idx++;
 976
 977         if (skip) {
 978                 /* if we skip this channel return to the decision state */
 979                 local->next_scan_state = SCAN_DECISION;
 980                 return;
 981         }
 982
 983         /*
 984          * Probe delay is used to update the NAV, cf. 11.1.3.2.2
 985          * (which unfortunately doesn't say _why_ step a) is done,
 986          * but it waits for the probe delay or until a frame is
 987          * received - and the received frame would update the NAV).
 988          * For now, we do not support waiting until a frame is
 989          * received.
 990          *
 991          * In any case, it is not necessary for a passive scan.
 992          */
 993         if ((chan->flags & (IEEE80211_CHAN_NO_IR | IEEE80211_CHAN_RADAR)) ||
 994             !scan_req->n_ssids) {
 995                 *next_delay = IEEE80211_PASSIVE_CHANNEL_TIME;
 996                 local->next_scan_state = SCAN_DECISION;
 997                 return;
 998         }
 999
1000         /* active scan, send probes */
1001         *next_delay = IEEE80211_PROBE_DELAY;
1002         local->next_scan_state = SCAN_SEND_PROBE;
1003 }
1004
1005 static void ieee80211_scan_state_suspend(struct ieee80211_local *local,
1006                                          unsigned long *next_delay)
1007 {
1008         /* switch back to the operating channel */
1009         local->scan_chandef.chan = NULL;
1010         ieee80211_hw_config(local, IEEE80211_CONF_CHANGE_CHANNEL);
1011
1012         /* disable PS */
1013         ieee80211_offchannel_return(local);
1014
1015         *next_delay = HZ / 5;
1016         /* afterwards, resume scan & go to next channel */
1017         local->next_scan_state = SCAN_RESUME;
1018 }
1019
1020 static void ieee80211_scan_state_resume(struct ieee80211_local *local,
1021                                         unsigned long *next_delay)
1022 {
1023         ieee80211_offchannel_stop_vifs(local);
1024
1025         if (local->ops->flush) {
1026                 ieee80211_flush_queues(local, NULL, false);
1027                 *next_delay = 0;
1028         } else
1029                 *next_delay = HZ / 10;
1030
1031         /* remember when we left the operating channel */
1032         local->leave_oper_channel_time = jiffies;
1033
1034         /* advance to the next channel to be scanned */
1035         local->next_scan_state = SCAN_SET_CHANNEL;
1036 }
1037
1038 void ieee80211_scan_work(struct work_struct *work)
1039 {
1040         struct ieee80211_local *local =
1041                 container_of(work, struct ieee80211_local, scan_work.work);
1042         struct ieee80211_sub_if_data *sdata;
1043         struct cfg80211_scan_request *scan_req;
1044         unsigned long next_delay = 0;
1045         bool aborted;
1046
1047         mutex_lock(&local->mtx);
1048
1049         if (!ieee80211_can_run_worker(local)) {
1050                 aborted = true;
1051                 goto out_complete;
1052         }
1053
1054         sdata = rcu_dereference_protected(local->scan_sdata,
1055                                           lockdep_is_held(&local->mtx));
1056         scan_req = rcu_dereference_protected(local->scan_req,
1057                                              lockdep_is_held(&local->mtx));
1058
1059         /* When scanning on-channel, the first-callback means completed. */
1060         if (test_bit(SCAN_ONCHANNEL_SCANNING, &local->scanning)) {
1061                 aborted = test_and_clear_bit(SCAN_ABORTED, &local->scanning);
1062                 goto out_complete;
1063         }
1064
1065         if (test_and_clear_bit(SCAN_COMPLETED, &local->scanning)) {
1066                 aborted = test_and_clear_bit(SCAN_ABORTED, &local->scanning);
1067                 goto out_complete;
1068         }
1069
1070         if (!sdata || !scan_req)
1071                 goto out;
1072
1073         if (!local->scanning) {
1074                 int rc;
1075
1076                 RCU_INIT_POINTER(local->scan_req, NULL);
1077                 RCU_INIT_POINTER(local->scan_sdata, NULL);
1078
1079                 rc = __ieee80211_start_scan(sdata, scan_req);
1080                 if (rc) {
1081                         /* need to complete scan in cfg80211 */
1082                         rcu_assign_pointer(local->scan_req, scan_req);
1083                         aborted = true;
1084                         goto out_complete;
1085                 } else
1086                         goto out;
1087         }
1088
1089         /*
1090          * as long as no delay is required advance immediately
1091          * without scheduling a new work
1092          */
1093         do {
1094                 if (!ieee80211_sdata_running(sdata)) {
1095                         aborted = true;
1096                         goto out_complete;
1097                 }
1098
1099                 switch (local->next_scan_state) {
1100                 case SCAN_DECISION:
1101                         /* if no more bands/channels left, complete scan */
1102                         if (local->scan_channel_idx >= scan_req->n_channels) {
1103                                 aborted = false;
1104                                 goto out_complete;
1105                         }
1106                         ieee80211_scan_state_decision(local, &next_delay);
1107                         break;
1108                 case SCAN_SET_CHANNEL:
1109                         ieee80211_scan_state_set_channel(local, &next_delay);
1110                         break;
1111                 case SCAN_SEND_PROBE:
1112                         ieee80211_scan_state_send_probe(local, &next_delay);
1113                         break;
1114                 case SCAN_SUSPEND:
1115                         ieee80211_scan_state_suspend(local, &next_delay);
1116                         break;
1117                 case SCAN_RESUME:
1118                         ieee80211_scan_state_resume(local, &next_delay);
1119                         break;
1120                 case SCAN_ABORT:
1121                         aborted = true;
1122                         goto out_complete;
1123                 }
1124         } while (next_delay == 0);
1125
1126         ieee80211_queue_delayed_work(&local->hw, &local->scan_work, next_delay);
1127         goto out;
1128
1129 out_complete:
1130         __ieee80211_scan_completed(&local->hw, aborted);
1131 out:
1132         mutex_unlock(&local->mtx);
1133 }
1134
1135 int ieee80211_request_scan(struct ieee80211_sub_if_data *sdata,
1136                            struct cfg80211_scan_request *req)
1137 {
1138         int res;
1139
1140         mutex_lock(&sdata->local->mtx);
1141         res = __ieee80211_start_scan(sdata, req);
1142         mutex_unlock(&sdata->local->mtx);
1143
1144         return res;
1145 }
1146
1147 int ieee80211_request_ibss_scan(struct ieee80211_sub_if_data *sdata,
1148                                 const u8 *ssid, u8 ssid_len,
1149                                 struct ieee80211_channel **channels,
1150                                 unsigned int n_channels,
1151                                 enum nl80211_bss_scan_width scan_width)
1152 {
1153         struct ieee80211_local *local = sdata->local;
1154         int ret = -EBUSY, i, n_ch = 0;
1155         enum nl80211_band band;
1156
1157         mutex_lock(&local->mtx);
1158
1159         /* busy scanning */
1160         if (local->scan_req)
1161                 goto unlock;
1162
1163         /* fill internal scan request */
1164         if (!channels) {
1165                 int max_n;
1166
1167                 for (band = 0; band < NUM_NL80211_BANDS; band++) {
1168                         if (!local->hw.wiphy->bands[band] ||
1169                             band == NL80211_BAND_6GHZ)
1170                                 continue;
1171
1172                         max_n = local->hw.wiphy->bands[band]->n_channels;
1173                         for (i = 0; i < max_n; i++) {
1174                                 struct ieee80211_channel *tmp_ch =
1175                                     &local->hw.wiphy->bands[band]->channels[i];
1176
1177                                 if (tmp_ch->flags & (IEEE80211_CHAN_NO_IR |
1178                                                      IEEE80211_CHAN_DISABLED))
1179                                         continue;
1180
1181                                 local->int_scan_req->channels[n_ch] = tmp_ch;
1182                                 n_ch++;
1183                         }
1184                 }
1185
1186                 if (WARN_ON_ONCE(n_ch == 0))
1187                         goto unlock;
1188
1189                 local->int_scan_req->n_channels = n_ch;
1190         } else {
1191                 for (i = 0; i < n_channels; i++) {
1192                         if (channels[i]->flags & (IEEE80211_CHAN_NO_IR |
1193                                                   IEEE80211_CHAN_DISABLED))
1194                                 continue;
1195
1196                         local->int_scan_req->channels[n_ch] = channels[i];
1197                         n_ch++;
1198                 }
1199
1200                 if (WARN_ON_ONCE(n_ch == 0))
1201                         goto unlock;
1202
1203                 local->int_scan_req->n_channels = n_ch;
1204         }
1205
1206         local->int_scan_req->ssids = &local->scan_ssid;
1207         local->int_scan_req->n_ssids = 1;
1208         local->int_scan_req->scan_width = scan_width;
1209         memcpy(local->int_scan_req->ssids[0].ssid, ssid, IEEE80211_MAX_SSID_LEN);
1210         local->int_scan_req->ssids[0].ssid_len = ssid_len;
1211
1212         ret = __ieee80211_start_scan(sdata, sdata->local->int_scan_req);
1213  unlock:
1214         mutex_unlock(&local->mtx);
1215         return ret;
1216 }
1217
1218 /*
1219  * Only call this function when a scan can't be queued -- under RTNL.
1220  */
1221 void ieee80211_scan_cancel(struct ieee80211_local *local)
1222 {
1223         /*
1224          * We are canceling software scan, or deferred scan that was not
1225          * yet really started (see __ieee80211_start_scan ).
1226          *
1227          * Regarding hardware scan:
1228          * - we can not call  __ieee80211_scan_completed() as when
1229          *   SCAN_HW_SCANNING bit is set this function change
1230          *   local->hw_scan_req to operate on 5G band, what race with
1231          *   driver which can use local->hw_scan_req
1232          *
1233          * - we can not cancel scan_work since driver can schedule it
1234          *   by ieee80211_scan_completed(..., true) to finish scan
1235          *
1236          * Hence we only call the cancel_hw_scan() callback, but the low-level
1237          * driver is still responsible for calling ieee80211_scan_completed()
1238          * after the scan was completed/aborted.
1239          */
1240
1241         mutex_lock(&local->mtx);
1242         if (!local->scan_req)
1243                 goto out;
1244
1245         /*
1246          * We have a scan running and the driver already reported completion,
1247          * but the worker hasn't run yet or is stuck on the mutex - mark it as
1248          * cancelled.
1249          */
1250         if (test_bit(SCAN_HW_SCANNING, &local->scanning) &&
1251             test_bit(SCAN_COMPLETED, &local->scanning)) {
1252                 set_bit(SCAN_HW_CANCELLED, &local->scanning);
1253                 goto out;
1254         }
1255
1256         if (test_bit(SCAN_HW_SCANNING, &local->scanning)) {
1257                 /*
1258                  * Make sure that __ieee80211_scan_completed doesn't trigger a
1259                  * scan on another band.
1260                  */
1261                 set_bit(SCAN_HW_CANCELLED, &local->scanning);
1262                 if (local->ops->cancel_hw_scan)
1263                         drv_cancel_hw_scan(local,
1264                                 rcu_dereference_protected(local->scan_sdata,
1265                                                 lockdep_is_held(&local->mtx)));
1266                 goto out;
1267         }
1268
1269         /*
1270          * If the work is currently running, it must be blocked on
1271          * the mutex, but we'll set scan_sdata = NULL and it'll
1272          * simply exit once it acquires the mutex.
1273          */
1274         cancel_delayed_work(&local->scan_work);
1275         /* and clean up */
1276         memset(&local->scan_info, 0, sizeof(local->scan_info));
1277         __ieee80211_scan_completed(&local->hw, true);
1278 out:
1279         mutex_unlock(&local->mtx);
1280 }
1281
1282 int __ieee80211_request_sched_scan_start(struct ieee80211_sub_if_data *sdata,
1283                                         struct cfg80211_sched_scan_request *req)
1284 {
1285         struct ieee80211_local *local = sdata->local;
1286         struct ieee80211_scan_ies sched_scan_ies = {};
1287         struct cfg80211_chan_def chandef;
1288         int ret, i, iebufsz, num_bands = 0;
1289         u32 rate_masks[NUM_NL80211_BANDS] = {};
1290         u8 bands_used = 0;
1291         u8 *ie;
1292         u32 flags = 0;
1293
1294         iebufsz = local->scan_ies_len + req->ie_len;
1295
1296         lockdep_assert_held(&local->mtx);
1297
1298         if (!local->ops->sched_scan_start)
1299                 return -ENOTSUPP;
1300
1301         for (i = 0; i < NUM_NL80211_BANDS; i++) {
1302                 if (local->hw.wiphy->bands[i]) {
1303                         bands_used |= BIT(i);
1304                         rate_masks[i] = (u32) -1;
1305                         num_bands++;
1306                 }
1307         }
1308
1309         if (req->flags & NL80211_SCAN_FLAG_MIN_PREQ_CONTENT)
1310                 flags |= IEEE80211_PROBE_FLAG_MIN_CONTENT;
1311
1312         ie = kcalloc(iebufsz, num_bands, GFP_KERNEL);
1313         if (!ie) {
1314                 ret = -ENOMEM;
1315                 goto out;
1316         }
1317
1318         ieee80211_prepare_scan_chandef(&chandef, req->scan_width);
1319
1320         ieee80211_build_preq_ies(sdata, ie, num_bands * iebufsz,
1321                                  &sched_scan_ies, req->ie,
1322                                  req->ie_len, bands_used, rate_masks, &chandef,
1323                                  flags);
1324
1325         ret = drv_sched_scan_start(local, sdata, req, &sched_scan_ies);
1326         if (ret == 0) {
1327                 rcu_assign_pointer(local->sched_scan_sdata, sdata);
1328                 rcu_assign_pointer(local->sched_scan_req, req);
1329         }
1330
1331         kfree(ie);
1332
1333 out:
1334         if (ret) {
1335                 /* Clean in case of failure after HW restart or upon resume. */
1336                 RCU_INIT_POINTER(local->sched_scan_sdata, NULL);
1337                 RCU_INIT_POINTER(local->sched_scan_req, NULL);
1338         }
1339
1340         return ret;
1341 }
1342
1343 int ieee80211_request_sched_scan_start(struct ieee80211_sub_if_data *sdata,
1344                                        struct cfg80211_sched_scan_request *req)
1345 {
1346         struct ieee80211_local *local = sdata->local;
1347         int ret;
1348
1349         mutex_lock(&local->mtx);
1350
1351         if (rcu_access_pointer(local->sched_scan_sdata)) {
1352                 mutex_unlock(&local->mtx);
1353                 return -EBUSY;
1354         }
1355
1356         ret = __ieee80211_request_sched_scan_start(sdata, req);
1357
1358         mutex_unlock(&local->mtx);
1359         return ret;
1360 }
1361
1362 int ieee80211_request_sched_scan_stop(struct ieee80211_local *local)
1363 {
1364         struct ieee80211_sub_if_data *sched_scan_sdata;
1365         int ret = -ENOENT;
1366
1367         mutex_lock(&local->mtx);
1368
1369         if (!local->ops->sched_scan_stop) {
1370                 ret = -ENOTSUPP;
1371                 goto out;
1372         }
1373
1374         /* We don't want to restart sched scan anymore. */
1375         RCU_INIT_POINTER(local->sched_scan_req, NULL);
1376
1377         sched_scan_sdata = rcu_dereference_protected(local->sched_scan_sdata,
1378                                                 lockdep_is_held(&local->mtx));
1379         if (sched_scan_sdata) {
1380                 ret = drv_sched_scan_stop(local, sched_scan_sdata);
1381                 if (!ret)
1382                         RCU_INIT_POINTER(local->sched_scan_sdata, NULL);
1383         }
1384 out:
1385         mutex_unlock(&local->mtx);
1386
1387         return ret;
1388 }
1389
1390 void ieee80211_sched_scan_results(struct ieee80211_hw *hw)
1391 {
1392         struct ieee80211_local *local = hw_to_local(hw);
1393
1394         trace_api_sched_scan_results(local);
1395
1396         cfg80211_sched_scan_results(hw->wiphy, 0);
1397 }
1398 EXPORT_SYMBOL(ieee80211_sched_scan_results);
1399
1400 void ieee80211_sched_scan_end(struct ieee80211_local *local)
1401 {
1402         mutex_lock(&local->mtx);
1403
1404         if (!rcu_access_pointer(local->sched_scan_sdata)) {
1405                 mutex_unlock(&local->mtx);
1406                 return;
1407         }
1408
1409         RCU_INIT_POINTER(local->sched_scan_sdata, NULL);
1410
1411         /* If sched scan was aborted by the driver. */
1412         RCU_INIT_POINTER(local->sched_scan_req, NULL);
1413
1414         mutex_unlock(&local->mtx);
1415
1416         cfg80211_sched_scan_stopped(local->hw.wiphy, 0);
1417 }
1418
1419 void ieee80211_sched_scan_stopped_work(struct work_struct *work)
1420 {
1421         struct ieee80211_local *local =
1422                 container_of(work, struct ieee80211_local,
1423                              sched_scan_stopped_work);
1424
1425         ieee80211_sched_scan_end(local);
1426 }
1427
1428 void ieee80211_sched_scan_stopped(struct ieee80211_hw *hw)
1429 {
1430         struct ieee80211_local *local = hw_to_local(hw);
1431
1432         trace_api_sched_scan_stopped(local);
1433
1434         /*
1435          * this shouldn't really happen, so for simplicity
1436          * simply ignore it, and let mac80211 reconfigure
1437          * the sched scan later on.
1438          */
1439         if (local->in_reconfig)
1440                 return;
1441
1442         schedule_work(&local->sched_scan_stopped_work);
1443 }
1444 EXPORT_SYMBOL(ieee80211_sched_scan_stopped);