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) 2018-2021 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         elems = ieee802_11_parse_elems(elements, len - baselen, false,
 213                                        mgmt->bssid, cbss->bssid);
 214         if (!elems)
 215                 return NULL;
 216
 217         /* In case the signal is invalid update the status */
 218         signal_valid = channel == cbss->channel;
 219         if (!signal_valid)
 220                 rx_status->flag |= RX_FLAG_NO_SIGNAL_VAL;
 221
 222         bss = (void *)cbss->priv;
 223         ieee80211_update_bss_from_elems(local, bss, elems, rx_status, beacon);
 224
 225         list_for_each_entry(non_tx_cbss, &cbss->nontrans_list, nontrans_list) {
 226                 non_tx_bss = (void *)non_tx_cbss->priv;
 227
 228                 ieee80211_update_bss_from_elems(local, non_tx_bss, elems,
 229                                                 rx_status, beacon);
 230         }
 231
 232         kfree(elems);
 233
 234         return bss;
 235 }
 236
 237 static bool ieee80211_scan_accept_presp(struct ieee80211_sub_if_data *sdata,
 238                                         u32 scan_flags, const u8 *da)
 239 {
 240         if (!sdata)
 241                 return false;
 242         /* accept broadcast for OCE */
 243         if (scan_flags & NL80211_SCAN_FLAG_ACCEPT_BCAST_PROBE_RESP &&
 244             is_broadcast_ether_addr(da))
 245                 return true;
 246         if (scan_flags & NL80211_SCAN_FLAG_RANDOM_ADDR)
 247                 return true;
 248         return ether_addr_equal(da, sdata->vif.addr);
 249 }
 250
 251 void ieee80211_scan_rx(struct ieee80211_local *local, struct sk_buff *skb)
 252 {
 253         struct ieee80211_rx_status *rx_status = IEEE80211_SKB_RXCB(skb);
 254         struct ieee80211_sub_if_data *sdata1, *sdata2;
 255         struct ieee80211_mgmt *mgmt = (void *)skb->data;
 256         struct ieee80211_bss *bss;
 257         struct ieee80211_channel *channel;
 258         size_t min_hdr_len = offsetof(struct ieee80211_mgmt,
 259                                       u.probe_resp.variable);
 260
 261         if (!ieee80211_is_probe_resp(mgmt->frame_control) &&
 262             !ieee80211_is_beacon(mgmt->frame_control) &&
 263             !ieee80211_is_s1g_beacon(mgmt->frame_control))
 264                 return;
 265
 266         if (ieee80211_is_s1g_beacon(mgmt->frame_control)) {
 267                 if (ieee80211_is_s1g_short_beacon(mgmt->frame_control))
 268                         min_hdr_len = offsetof(struct ieee80211_ext,
 269                                                u.s1g_short_beacon.variable);
 270                 else
 271                         min_hdr_len = offsetof(struct ieee80211_ext,
 272                                                u.s1g_beacon);
 273         }
 274
 275         if (skb->len < min_hdr_len)
 276                 return;
 277
 278         sdata1 = rcu_dereference(local->scan_sdata);
 279         sdata2 = rcu_dereference(local->sched_scan_sdata);
 280
 281         if (likely(!sdata1 && !sdata2))
 282                 return;
 283
 284         if (test_and_clear_bit(SCAN_BEACON_WAIT, &local->scanning)) {
 285                 /*
 286                  * we were passive scanning because of radar/no-IR, but
 287                  * the beacon/proberesp rx gives us an opportunity to upgrade
 288                  * to active scan
 289                  */
 290                  set_bit(SCAN_BEACON_DONE, &local->scanning);
 291                  ieee80211_queue_delayed_work(&local->hw, &local->scan_work, 0);
 292         }
 293
 294         if (ieee80211_is_probe_resp(mgmt->frame_control)) {
 295                 struct cfg80211_scan_request *scan_req;
 296                 struct cfg80211_sched_scan_request *sched_scan_req;
 297                 u32 scan_req_flags = 0, sched_scan_req_flags = 0;
 298
 299                 scan_req = rcu_dereference(local->scan_req);
 300                 sched_scan_req = rcu_dereference(local->sched_scan_req);
 301
 302                 if (scan_req)
 303                         scan_req_flags = scan_req->flags;
 304
 305                 if (sched_scan_req)
 306                         sched_scan_req_flags = sched_scan_req->flags;
 307
 308                 /* ignore ProbeResp to foreign address or non-bcast (OCE)
 309                  * unless scanning with randomised address
 310                  */
 311                 if (!ieee80211_scan_accept_presp(sdata1, scan_req_flags,
 312                                                  mgmt->da) &&
 313                     !ieee80211_scan_accept_presp(sdata2, sched_scan_req_flags,
 314                                                  mgmt->da))
 315                         return;
 316         }
 317
 318         channel = ieee80211_get_channel_khz(local->hw.wiphy,
 319                                         ieee80211_rx_status_to_khz(rx_status));
 320
 321         if (!channel || channel->flags & IEEE80211_CHAN_DISABLED)
 322                 return;
 323
 324         bss = ieee80211_bss_info_update(local, rx_status,
 325                                         mgmt, skb->len,
 326                                         channel);
 327         if (bss)
 328                 ieee80211_rx_bss_put(local, bss);
 329 }
 330
 331 static void
 332 ieee80211_prepare_scan_chandef(struct cfg80211_chan_def *chandef,
 333                                enum nl80211_bss_scan_width scan_width)
 334 {
 335         memset(chandef, 0, sizeof(*chandef));
 336         switch (scan_width) {
 337         case NL80211_BSS_CHAN_WIDTH_5:
 338                 chandef->width = NL80211_CHAN_WIDTH_5;
 339                 break;
 340         case NL80211_BSS_CHAN_WIDTH_10:
 341                 chandef->width = NL80211_CHAN_WIDTH_10;
 342                 break;
 343         default:
 344                 chandef->width = NL80211_CHAN_WIDTH_20_NOHT;
 345                 break;
 346         }
 347 }
 348
 349 /* return false if no more work */
 350 static bool ieee80211_prep_hw_scan(struct ieee80211_sub_if_data *sdata)
 351 {
 352         struct ieee80211_local *local = sdata->local;
 353         struct cfg80211_scan_request *req;
 354         struct cfg80211_chan_def chandef;
 355         u8 bands_used = 0;
 356         int i, ielen, n_chans;
 357         u32 flags = 0;
 358
 359         req = rcu_dereference_protected(local->scan_req,
 360                                         lockdep_is_held(&local->mtx));
 361
 362         if (test_bit(SCAN_HW_CANCELLED, &local->scanning))
 363                 return false;
 364
 365         if (ieee80211_hw_check(&local->hw, SINGLE_SCAN_ON_ALL_BANDS)) {
 366                 for (i = 0; i < req->n_channels; i++) {
 367                         local->hw_scan_req->req.channels[i] = req->channels[i];
 368                         bands_used |= BIT(req->channels[i]->band);
 369                 }
 370
 371                 n_chans = req->n_channels;
 372         } else {
 373                 do {
 374                         if (local->hw_scan_band == NUM_NL80211_BANDS)
 375                                 return false;
 376
 377                         n_chans = 0;
 378
 379                         for (i = 0; i < req->n_channels; i++) {
 380                                 if (req->channels[i]->band !=
 381                                     local->hw_scan_band)
 382                                         continue;
 383                                 local->hw_scan_req->req.channels[n_chans] =
 384                                                         req->channels[i];
 385                                 n_chans++;
 386                                 bands_used |= BIT(req->channels[i]->band);
 387                         }
 388
 389                         local->hw_scan_band++;
 390                 } while (!n_chans);
 391         }
 392
 393         local->hw_scan_req->req.n_channels = n_chans;
 394         ieee80211_prepare_scan_chandef(&chandef, req->scan_width);
 395
 396         if (req->flags & NL80211_SCAN_FLAG_MIN_PREQ_CONTENT)
 397                 flags |= IEEE80211_PROBE_FLAG_MIN_CONTENT;
 398
 399         ielen = ieee80211_build_preq_ies(sdata,
 400                                          (u8 *)local->hw_scan_req->req.ie,
 401                                          local->hw_scan_ies_bufsize,
 402                                          &local->hw_scan_req->ies,
 403                                          req->ie, req->ie_len,
 404                                          bands_used, req->rates, &chandef,
 405                                          flags);
 406         local->hw_scan_req->req.ie_len = ielen;
 407         local->hw_scan_req->req.no_cck = req->no_cck;
 408         ether_addr_copy(local->hw_scan_req->req.mac_addr, req->mac_addr);
 409         ether_addr_copy(local->hw_scan_req->req.mac_addr_mask,
 410                         req->mac_addr_mask);
 411         ether_addr_copy(local->hw_scan_req->req.bssid, req->bssid);
 412
 413         return true;
 414 }
 415
 416 static void __ieee80211_scan_completed(struct ieee80211_hw *hw, bool aborted)
 417 {
 418         struct ieee80211_local *local = hw_to_local(hw);
 419         bool hw_scan = test_bit(SCAN_HW_SCANNING, &local->scanning);
 420         bool was_scanning = local->scanning;
 421         struct cfg80211_scan_request *scan_req;
 422         struct ieee80211_sub_if_data *scan_sdata;
 423         struct ieee80211_sub_if_data *sdata;
 424
 425         lockdep_assert_held(&local->mtx);
 426
 427         /*
 428          * It's ok to abort a not-yet-running scan (that
 429          * we have one at all will be verified by checking
 430          * local->scan_req next), but not to complete it
 431          * successfully.
 432          */
 433         if (WARN_ON(!local->scanning && !aborted))
 434                 aborted = true;
 435
 436         if (WARN_ON(!local->scan_req))
 437                 return;
 438
 439         scan_sdata = rcu_dereference_protected(local->scan_sdata,
 440                                                lockdep_is_held(&local->mtx));
 441
 442         if (hw_scan && !aborted &&
 443             !ieee80211_hw_check(&local->hw, SINGLE_SCAN_ON_ALL_BANDS) &&
 444             ieee80211_prep_hw_scan(scan_sdata)) {
 445                 int rc;
 446
 447                 rc = drv_hw_scan(local,
 448                         rcu_dereference_protected(local->scan_sdata,
 449                                                   lockdep_is_held(&local->mtx)),
 450                         local->hw_scan_req);
 451
 452                 if (rc == 0)
 453                         return;
 454
 455                 /* HW scan failed and is going to be reported as aborted,
 456                  * so clear old scan info.
 457                  */
 458                 memset(&local->scan_info, 0, sizeof(local->scan_info));
 459                 aborted = true;
 460         }
 461
 462         kfree(local->hw_scan_req);
 463         local->hw_scan_req = NULL;
 464
 465         scan_req = rcu_dereference_protected(local->scan_req,
 466                                              lockdep_is_held(&local->mtx));
 467
 468         RCU_INIT_POINTER(local->scan_req, NULL);
 469         RCU_INIT_POINTER(local->scan_sdata, NULL);
 470
 471         local->scanning = 0;
 472         local->scan_chandef.chan = NULL;
 473
 474         synchronize_rcu();
 475
 476         if (scan_req != local->int_scan_req) {
 477                 local->scan_info.aborted = aborted;
 478                 cfg80211_scan_done(scan_req, &local->scan_info);
 479         }
 480
 481         /* Set power back to normal operating levels. */
 482         ieee80211_hw_config(local, 0);
 483
 484         if (!hw_scan) {
 485                 ieee80211_configure_filter(local);
 486                 drv_sw_scan_complete(local, scan_sdata);
 487                 ieee80211_offchannel_return(local);
 488         }
 489
 490         ieee80211_recalc_idle(local);
 491
 492         ieee80211_mlme_notify_scan_completed(local);
 493         ieee80211_ibss_notify_scan_completed(local);
 494
 495         /* Requeue all the work that might have been ignored while
 496          * the scan was in progress; if there was none this will
 497          * just be a no-op for the particular interface.
 498          */
 499         list_for_each_entry_rcu(sdata, &local->interfaces, list) {
 500                 if (ieee80211_sdata_running(sdata))
 501                         ieee80211_queue_work(&sdata->local->hw, &sdata->work);
 502         }
 503
 504         if (was_scanning)
 505                 ieee80211_start_next_roc(local);
 506 }
 507
 508 void ieee80211_scan_completed(struct ieee80211_hw *hw,
 509                               struct cfg80211_scan_info *info)
 510 {
 511         struct ieee80211_local *local = hw_to_local(hw);
 512
 513         trace_api_scan_completed(local, info->aborted);
 514
 515         set_bit(SCAN_COMPLETED, &local->scanning);
 516         if (info->aborted)
 517                 set_bit(SCAN_ABORTED, &local->scanning);
 518
 519         memcpy(&local->scan_info, info, sizeof(*info));
 520
 521         ieee80211_queue_delayed_work(&local->hw, &local->scan_work, 0);
 522 }
 523 EXPORT_SYMBOL(ieee80211_scan_completed);
 524
 525 static int ieee80211_start_sw_scan(struct ieee80211_local *local,
 526                                    struct ieee80211_sub_if_data *sdata)
 527 {
 528         /* Software scan is not supported in multi-channel cases */
 529         if (local->use_chanctx)
 530                 return -EOPNOTSUPP;
 531
 532         /*
 533          * Hardware/driver doesn't support hw_scan, so use software
 534          * scanning instead. First send a nullfunc frame with power save
 535          * bit on so that AP will buffer the frames for us while we are not
 536          * listening, then send probe requests to each channel and wait for
 537          * the responses. After all channels are scanned, tune back to the
 538          * original channel and send a nullfunc frame with power save bit
 539          * off to trigger the AP to send us all the buffered frames.
 540          *
 541          * Note that while local->sw_scanning is true everything else but
 542          * nullfunc frames and probe requests will be dropped in
 543          * ieee80211_tx_h_check_assoc().
 544          */
 545         drv_sw_scan_start(local, sdata, local->scan_addr);
 546
 547         local->leave_oper_channel_time = jiffies;
 548         local->next_scan_state = SCAN_DECISION;
 549         local->scan_channel_idx = 0;
 550
 551         ieee80211_offchannel_stop_vifs(local);
 552
 553         /* ensure nullfunc is transmitted before leaving operating channel */
 554         ieee80211_flush_queues(local, NULL, false);
 555
 556         ieee80211_configure_filter(local);
 557
 558         /* We need to set power level at maximum rate for scanning. */
 559         ieee80211_hw_config(local, 0);
 560
 561         ieee80211_queue_delayed_work(&local->hw,
 562                                      &local->scan_work, 0);
 563
 564         return 0;
 565 }
 566
 567 static bool __ieee80211_can_leave_ch(struct ieee80211_sub_if_data *sdata)
 568 {
 569         struct ieee80211_local *local = sdata->local;
 570         struct ieee80211_sub_if_data *sdata_iter;
 571
 572         if (!ieee80211_is_radar_required(local))
 573                 return true;
 574
 575         if (!regulatory_pre_cac_allowed(local->hw.wiphy))
 576                 return false;
 577
 578         mutex_lock(&local->iflist_mtx);
 579         list_for_each_entry(sdata_iter, &local->interfaces, list) {
 580                 if (sdata_iter->wdev.cac_started) {
 581                         mutex_unlock(&local->iflist_mtx);
 582                         return false;
 583                 }
 584         }
 585         mutex_unlock(&local->iflist_mtx);
 586
 587         return true;
 588 }
 589
 590 static bool ieee80211_can_scan(struct ieee80211_local *local,
 591                                struct ieee80211_sub_if_data *sdata)
 592 {
 593         if (!__ieee80211_can_leave_ch(sdata))
 594                 return false;
 595
 596         if (!list_empty(&local->roc_list))
 597                 return false;
 598
 599         if (sdata->vif.type == NL80211_IFTYPE_STATION &&
 600             sdata->u.mgd.flags & IEEE80211_STA_CONNECTION_POLL)
 601                 return false;
 602
 603         return true;
 604 }
 605
 606 void ieee80211_run_deferred_scan(struct ieee80211_local *local)
 607 {
 608         lockdep_assert_held(&local->mtx);
 609
 610         if (!local->scan_req || local->scanning)
 611                 return;
 612
 613         if (!ieee80211_can_scan(local,
 614                                 rcu_dereference_protected(
 615                                         local->scan_sdata,
 616                                         lockdep_is_held(&local->mtx))))
 617                 return;
 618
 619         ieee80211_queue_delayed_work(&local->hw, &local->scan_work,
 620                                      round_jiffies_relative(0));
 621 }
 622
 623 static void ieee80211_send_scan_probe_req(struct ieee80211_sub_if_data *sdata,
 624                                           const u8 *src, const u8 *dst,
 625                                           const u8 *ssid, size_t ssid_len,
 626                                           const u8 *ie, size_t ie_len,
 627                                           u32 ratemask, u32 flags, u32 tx_flags,
 628                                           struct ieee80211_channel *channel)
 629 {
 630         struct sk_buff *skb;
 631
 632         skb = ieee80211_build_probe_req(sdata, src, dst, ratemask, channel,
 633                                         ssid, ssid_len,
 634                                         ie, ie_len, flags);
 635
 636         if (skb) {
 637                 if (flags & IEEE80211_PROBE_FLAG_RANDOM_SN) {
 638                         struct ieee80211_hdr *hdr = (void *)skb->data;
 639                         struct ieee80211_tx_info *info = IEEE80211_SKB_CB(skb);
 640                         u16 sn = get_random_u32();
 641
 642                         info->control.flags |= IEEE80211_TX_CTRL_NO_SEQNO;
 643                         hdr->seq_ctrl =
 644                                 cpu_to_le16(IEEE80211_SN_TO_SEQ(sn));
 645                 }
 646                 IEEE80211_SKB_CB(skb)->flags |= tx_flags;
 647                 ieee80211_tx_skb_tid_band(sdata, skb, 7, channel->band);
 648         }
 649 }
 650
 651 static void ieee80211_scan_state_send_probe(struct ieee80211_local *local,
 652                                             unsigned long *next_delay)
 653 {
 654         int i;
 655         struct ieee80211_sub_if_data *sdata;
 656         struct cfg80211_scan_request *scan_req;
 657         enum nl80211_band band = local->hw.conf.chandef.chan->band;
 658         u32 flags = 0, tx_flags;
 659
 660         scan_req = rcu_dereference_protected(local->scan_req,
 661                                              lockdep_is_held(&local->mtx));
 662
 663         tx_flags = IEEE80211_TX_INTFL_OFFCHAN_TX_OK;
 664         if (scan_req->no_cck)
 665                 tx_flags |= IEEE80211_TX_CTL_NO_CCK_RATE;
 666         if (scan_req->flags & NL80211_SCAN_FLAG_MIN_PREQ_CONTENT)
 667                 flags |= IEEE80211_PROBE_FLAG_MIN_CONTENT;
 668         if (scan_req->flags & NL80211_SCAN_FLAG_RANDOM_SN)
 669                 flags |= IEEE80211_PROBE_FLAG_RANDOM_SN;
 670
 671         sdata = rcu_dereference_protected(local->scan_sdata,
 672                                           lockdep_is_held(&local->mtx));
 673
 674         for (i = 0; i < scan_req->n_ssids; i++)
 675                 ieee80211_send_scan_probe_req(
 676                         sdata, local->scan_addr, scan_req->bssid,
 677                         scan_req->ssids[i].ssid, scan_req->ssids[i].ssid_len,
 678                         scan_req->ie, scan_req->ie_len,
 679                         scan_req->rates[band], flags,
 680                         tx_flags, local->hw.conf.chandef.chan);
 681
 682         /*
 683          * After sending probe requests, wait for probe responses
 684          * on the channel.
 685          */
 686         *next_delay = IEEE80211_CHANNEL_TIME;
 687         local->next_scan_state = SCAN_DECISION;
 688 }
 689
 690 static int __ieee80211_start_scan(struct ieee80211_sub_if_data *sdata,
 691                                   struct cfg80211_scan_request *req)
 692 {
 693         struct ieee80211_local *local = sdata->local;
 694         bool hw_scan = local->ops->hw_scan;
 695         int rc;
 696
 697         lockdep_assert_held(&local->mtx);
 698
 699         if (local->scan_req)
 700                 return -EBUSY;
 701
 702         if (!__ieee80211_can_leave_ch(sdata))
 703                 return -EBUSY;
 704
 705         if (!ieee80211_can_scan(local, sdata)) {
 706                 /* wait for the work to finish/time out */
 707                 rcu_assign_pointer(local->scan_req, req);
 708                 rcu_assign_pointer(local->scan_sdata, sdata);
 709                 return 0;
 710         }
 711
 712  again:
 713         if (hw_scan) {
 714                 u8 *ies;
 715
 716                 local->hw_scan_ies_bufsize = local->scan_ies_len + req->ie_len;
 717
 718                 if (ieee80211_hw_check(&local->hw, SINGLE_SCAN_ON_ALL_BANDS)) {
 719                         int i, n_bands = 0;
 720                         u8 bands_counted = 0;
 721
 722                         for (i = 0; i < req->n_channels; i++) {
 723                                 if (bands_counted & BIT(req->channels[i]->band))
 724                                         continue;
 725                                 bands_counted |= BIT(req->channels[i]->band);
 726                                 n_bands++;
 727                         }
 728
 729                         local->hw_scan_ies_bufsize *= n_bands;
 730                 }
 731
 732                 local->hw_scan_req = kmalloc(
 733                                 sizeof(*local->hw_scan_req) +
 734                                 req->n_channels * sizeof(req->channels[0]) +
 735                                 local->hw_scan_ies_bufsize, GFP_KERNEL);
 736                 if (!local->hw_scan_req)
 737                         return -ENOMEM;
 738
 739                 local->hw_scan_req->req.ssids = req->ssids;
 740                 local->hw_scan_req->req.n_ssids = req->n_ssids;
 741                 ies = (u8 *)local->hw_scan_req +
 742                         sizeof(*local->hw_scan_req) +
 743                         req->n_channels * sizeof(req->channels[0]);
 744                 local->hw_scan_req->req.ie = ies;
 745                 local->hw_scan_req->req.flags = req->flags;
 746                 eth_broadcast_addr(local->hw_scan_req->req.bssid);
 747                 local->hw_scan_req->req.duration = req->duration;
 748                 local->hw_scan_req->req.duration_mandatory =
 749                         req->duration_mandatory;
 750
 751                 local->hw_scan_band = 0;
 752                 local->hw_scan_req->req.n_6ghz_params = req->n_6ghz_params;
 753                 local->hw_scan_req->req.scan_6ghz_params =
 754                         req->scan_6ghz_params;
 755                 local->hw_scan_req->req.scan_6ghz = req->scan_6ghz;
 756
 757                 /*
 758                  * After allocating local->hw_scan_req, we must
 759                  * go through until ieee80211_prep_hw_scan(), so
 760                  * anything that might be changed here and leave
 761                  * this function early must not go after this
 762                  * allocation.
 763                  */
 764         }
 765
 766         rcu_assign_pointer(local->scan_req, req);
 767         rcu_assign_pointer(local->scan_sdata, sdata);
 768
 769         if (req->flags & NL80211_SCAN_FLAG_RANDOM_ADDR)
 770                 get_random_mask_addr(local->scan_addr,
 771                                      req->mac_addr,
 772                                      req->mac_addr_mask);
 773         else
 774                 memcpy(local->scan_addr, sdata->vif.addr, ETH_ALEN);
 775
 776         if (hw_scan) {
 777                 __set_bit(SCAN_HW_SCANNING, &local->scanning);
 778         } else if ((req->n_channels == 1) &&
 779                    (req->channels[0] == local->_oper_chandef.chan)) {
 780                 /*
 781                  * If we are scanning only on the operating channel
 782                  * then we do not need to stop normal activities
 783                  */
 784                 unsigned long next_delay;
 785
 786                 __set_bit(SCAN_ONCHANNEL_SCANNING, &local->scanning);
 787
 788                 ieee80211_recalc_idle(local);
 789
 790                 /* Notify driver scan is starting, keep order of operations
 791                  * same as normal software scan, in case that matters. */
 792                 drv_sw_scan_start(local, sdata, local->scan_addr);
 793
 794                 ieee80211_configure_filter(local); /* accept probe-responses */
 795
 796                 /* We need to ensure power level is at max for scanning. */
 797                 ieee80211_hw_config(local, 0);
 798
 799                 if ((req->channels[0]->flags & (IEEE80211_CHAN_NO_IR |
 800                                                 IEEE80211_CHAN_RADAR)) ||
 801                     !req->n_ssids) {
 802                         next_delay = IEEE80211_PASSIVE_CHANNEL_TIME;
 803                         if (req->n_ssids)
 804                                 set_bit(SCAN_BEACON_WAIT, &local->scanning);
 805                 } else {
 806                         ieee80211_scan_state_send_probe(local, &next_delay);
 807                         next_delay = IEEE80211_CHANNEL_TIME;
 808                 }
 809
 810                 /* Now, just wait a bit and we are all done! */
 811                 ieee80211_queue_delayed_work(&local->hw, &local->scan_work,
 812                                              next_delay);
 813                 return 0;
 814         } else {
 815                 /* Do normal software scan */
 816                 __set_bit(SCAN_SW_SCANNING, &local->scanning);
 817         }
 818
 819         ieee80211_recalc_idle(local);
 820
 821         if (hw_scan) {
 822                 WARN_ON(!ieee80211_prep_hw_scan(sdata));
 823                 rc = drv_hw_scan(local, sdata, local->hw_scan_req);
 824         } else {
 825                 rc = ieee80211_start_sw_scan(local, sdata);
 826         }
 827
 828         if (rc) {
 829                 kfree(local->hw_scan_req);
 830                 local->hw_scan_req = NULL;
 831                 local->scanning = 0;
 832
 833                 ieee80211_recalc_idle(local);
 834
 835                 local->scan_req = NULL;
 836                 RCU_INIT_POINTER(local->scan_sdata, NULL);
 837         }
 838
 839         if (hw_scan && rc == 1) {
 840                 /*
 841                  * we can't fall back to software for P2P-GO
 842                  * as it must update NoA etc.
 843                  */
 844                 if (ieee80211_vif_type_p2p(&sdata->vif) ==
 845                                 NL80211_IFTYPE_P2P_GO)
 846                         return -EOPNOTSUPP;
 847                 hw_scan = false;
 848                 goto again;
 849         }
 850
 851         return rc;
 852 }
 853
 854 static unsigned long
 855 ieee80211_scan_get_channel_time(struct ieee80211_channel *chan)
 856 {
 857         /*
 858          * TODO: channel switching also consumes quite some time,
 859          * add that delay as well to get a better estimation
 860          */
 861         if (chan->flags & (IEEE80211_CHAN_NO_IR | IEEE80211_CHAN_RADAR))
 862                 return IEEE80211_PASSIVE_CHANNEL_TIME;
 863         return IEEE80211_PROBE_DELAY + IEEE80211_CHANNEL_TIME;
 864 }
 865
 866 static void ieee80211_scan_state_decision(struct ieee80211_local *local,
 867                                           unsigned long *next_delay)
 868 {
 869         bool associated = false;
 870         bool tx_empty = true;
 871         bool bad_latency;
 872         struct ieee80211_sub_if_data *sdata;
 873         struct ieee80211_channel *next_chan;
 874         enum mac80211_scan_state next_scan_state;
 875         struct cfg80211_scan_request *scan_req;
 876
 877         /*
 878          * check if at least one STA interface is associated,
 879          * check if at least one STA interface has pending tx frames
 880          * and grab the lowest used beacon interval
 881          */
 882         mutex_lock(&local->iflist_mtx);
 883         list_for_each_entry(sdata, &local->interfaces, list) {
 884                 if (!ieee80211_sdata_running(sdata))
 885                         continue;
 886
 887                 if (sdata->vif.type == NL80211_IFTYPE_STATION) {
 888                         if (sdata->u.mgd.associated) {
 889                                 associated = true;
 890
 891                                 if (!qdisc_all_tx_empty(sdata->dev)) {
 892                                         tx_empty = false;
 893                                         break;
 894                                 }
 895                         }
 896                 }
 897         }
 898         mutex_unlock(&local->iflist_mtx);
 899
 900         scan_req = rcu_dereference_protected(local->scan_req,
 901                                              lockdep_is_held(&local->mtx));
 902
 903         next_chan = scan_req->channels[local->scan_channel_idx];
 904
 905         /*
 906          * we're currently scanning a different channel, let's
 907          * see if we can scan another channel without interfering
 908          * with the current traffic situation.
 909          *
 910          * Keep good latency, do not stay off-channel more than 125 ms.
 911          */
 912
 913         bad_latency = time_after(jiffies +
 914                                  ieee80211_scan_get_channel_time(next_chan),
 915                                  local->leave_oper_channel_time + HZ / 8);
 916
 917         if (associated && !tx_empty) {
 918                 if (scan_req->flags & NL80211_SCAN_FLAG_LOW_PRIORITY)
 919                         next_scan_state = SCAN_ABORT;
 920                 else
 921                         next_scan_state = SCAN_SUSPEND;
 922         } else if (associated && bad_latency) {
 923                 next_scan_state = SCAN_SUSPEND;
 924         } else {
 925                 next_scan_state = SCAN_SET_CHANNEL;
 926         }
 927
 928         local->next_scan_state = next_scan_state;
 929
 930         *next_delay = 0;
 931 }
 932
 933 static void ieee80211_scan_state_set_channel(struct ieee80211_local *local,
 934                                              unsigned long *next_delay)
 935 {
 936         int skip;
 937         struct ieee80211_channel *chan;
 938         enum nl80211_bss_scan_width oper_scan_width;
 939         struct cfg80211_scan_request *scan_req;
 940
 941         scan_req = rcu_dereference_protected(local->scan_req,
 942                                              lockdep_is_held(&local->mtx));
 943
 944         skip = 0;
 945         chan = scan_req->channels[local->scan_channel_idx];
 946
 947         local->scan_chandef.chan = chan;
 948         local->scan_chandef.center_freq1 = chan->center_freq;
 949         local->scan_chandef.freq1_offset = chan->freq_offset;
 950         local->scan_chandef.center_freq2 = 0;
 951
 952         /* For scanning on the S1G band, ignore scan_width (which is constant
 953          * across all channels) for now since channel width is specific to each
 954          * channel. Detect the required channel width here and likely revisit
 955          * later. Maybe scan_width could be used to build the channel scan list?
 956          */
 957         if (chan->band == NL80211_BAND_S1GHZ) {
 958                 local->scan_chandef.width = ieee80211_s1g_channel_width(chan);
 959                 goto set_channel;
 960         }
 961
 962         switch (scan_req->scan_width) {
 963         case NL80211_BSS_CHAN_WIDTH_5:
 964                 local->scan_chandef.width = NL80211_CHAN_WIDTH_5;
 965                 break;
 966         case NL80211_BSS_CHAN_WIDTH_10:
 967                 local->scan_chandef.width = NL80211_CHAN_WIDTH_10;
 968                 break;
 969         default:
 970         case NL80211_BSS_CHAN_WIDTH_20:
 971                 /* If scanning on oper channel, use whatever channel-type
 972                  * is currently in use.
 973                  */
 974                 oper_scan_width = cfg80211_chandef_to_scan_width(
 975                                         &local->_oper_chandef);
 976                 if (chan == local->_oper_chandef.chan &&
 977                     oper_scan_width == scan_req->scan_width)
 978                         local->scan_chandef = local->_oper_chandef;
 979                 else
 980                         local->scan_chandef.width = NL80211_CHAN_WIDTH_20_NOHT;
 981                 break;
 982         case NL80211_BSS_CHAN_WIDTH_1:
 983         case NL80211_BSS_CHAN_WIDTH_2:
 984                 /* shouldn't get here, S1G handled above */
 985                 WARN_ON(1);
 986                 break;
 987         }
 988
 989 set_channel:
 990         if (ieee80211_hw_config(local, IEEE80211_CONF_CHANGE_CHANNEL))
 991                 skip = 1;
 992
 993         /* advance state machine to next channel/band */
 994         local->scan_channel_idx++;
 995
 996         if (skip) {
 997                 /* if we skip this channel return to the decision state */
 998                 local->next_scan_state = SCAN_DECISION;
 999                 return;
1000         }
1001
1002         /*
1003          * Probe delay is used to update the NAV, cf. 11.1.3.2.2
1004          * (which unfortunately doesn't say _why_ step a) is done,
1005          * but it waits for the probe delay or until a frame is
1006          * received - and the received frame would update the NAV).
1007          * For now, we do not support waiting until a frame is
1008          * received.
1009          *
1010          * In any case, it is not necessary for a passive scan.
1011          */
1012         if ((chan->flags & (IEEE80211_CHAN_NO_IR | IEEE80211_CHAN_RADAR)) ||
1013             !scan_req->n_ssids) {
1014                 *next_delay = IEEE80211_PASSIVE_CHANNEL_TIME;
1015                 local->next_scan_state = SCAN_DECISION;
1016                 if (scan_req->n_ssids)
1017                         set_bit(SCAN_BEACON_WAIT, &local->scanning);
1018                 return;
1019         }
1020
1021         /* active scan, send probes */
1022         *next_delay = IEEE80211_PROBE_DELAY;
1023         local->next_scan_state = SCAN_SEND_PROBE;
1024 }
1025
1026 static void ieee80211_scan_state_suspend(struct ieee80211_local *local,
1027                                          unsigned long *next_delay)
1028 {
1029         /* switch back to the operating channel */
1030         local->scan_chandef.chan = NULL;
1031         ieee80211_hw_config(local, IEEE80211_CONF_CHANGE_CHANNEL);
1032
1033         /* disable PS */
1034         ieee80211_offchannel_return(local);
1035
1036         *next_delay = HZ / 5;
1037         /* afterwards, resume scan & go to next channel */
1038         local->next_scan_state = SCAN_RESUME;
1039 }
1040
1041 static void ieee80211_scan_state_resume(struct ieee80211_local *local,
1042                                         unsigned long *next_delay)
1043 {
1044         ieee80211_offchannel_stop_vifs(local);
1045
1046         if (local->ops->flush) {
1047                 ieee80211_flush_queues(local, NULL, false);
1048                 *next_delay = 0;
1049         } else
1050                 *next_delay = HZ / 10;
1051
1052         /* remember when we left the operating channel */
1053         local->leave_oper_channel_time = jiffies;
1054
1055         /* advance to the next channel to be scanned */
1056         local->next_scan_state = SCAN_SET_CHANNEL;
1057 }
1058
1059 void ieee80211_scan_work(struct work_struct *work)
1060 {
1061         struct ieee80211_local *local =
1062                 container_of(work, struct ieee80211_local, scan_work.work);
1063         struct ieee80211_sub_if_data *sdata;
1064         struct cfg80211_scan_request *scan_req;
1065         unsigned long next_delay = 0;
1066         bool aborted;
1067
1068         mutex_lock(&local->mtx);
1069
1070         if (!ieee80211_can_run_worker(local)) {
1071                 aborted = true;
1072                 goto out_complete;
1073         }
1074
1075         sdata = rcu_dereference_protected(local->scan_sdata,
1076                                           lockdep_is_held(&local->mtx));
1077         scan_req = rcu_dereference_protected(local->scan_req,
1078                                              lockdep_is_held(&local->mtx));
1079
1080         /* When scanning on-channel, the first-callback means completed. */
1081         if (test_bit(SCAN_ONCHANNEL_SCANNING, &local->scanning)) {
1082                 aborted = test_and_clear_bit(SCAN_ABORTED, &local->scanning);
1083                 goto out_complete;
1084         }
1085
1086         if (test_and_clear_bit(SCAN_COMPLETED, &local->scanning)) {
1087                 aborted = test_and_clear_bit(SCAN_ABORTED, &local->scanning);
1088                 goto out_complete;
1089         }
1090
1091         if (!sdata || !scan_req)
1092                 goto out;
1093
1094         if (!local->scanning) {
1095                 int rc;
1096
1097                 RCU_INIT_POINTER(local->scan_req, NULL);
1098                 RCU_INIT_POINTER(local->scan_sdata, NULL);
1099
1100                 rc = __ieee80211_start_scan(sdata, scan_req);
1101                 if (rc) {
1102                         /* need to complete scan in cfg80211 */
1103                         rcu_assign_pointer(local->scan_req, scan_req);
1104                         aborted = true;
1105                         goto out_complete;
1106                 } else
1107                         goto out;
1108         }
1109
1110         clear_bit(SCAN_BEACON_WAIT, &local->scanning);
1111
1112         /*
1113          * as long as no delay is required advance immediately
1114          * without scheduling a new work
1115          */
1116         do {
1117                 if (!ieee80211_sdata_running(sdata)) {
1118                         aborted = true;
1119                         goto out_complete;
1120                 }
1121
1122                 if (test_and_clear_bit(SCAN_BEACON_DONE, &local->scanning) &&
1123                     local->next_scan_state == SCAN_DECISION)
1124                         local->next_scan_state = SCAN_SEND_PROBE;
1125
1126                 switch (local->next_scan_state) {
1127                 case SCAN_DECISION:
1128                         /* if no more bands/channels left, complete scan */
1129                         if (local->scan_channel_idx >= scan_req->n_channels) {
1130                                 aborted = false;
1131                                 goto out_complete;
1132                         }
1133                         ieee80211_scan_state_decision(local, &next_delay);
1134                         break;
1135                 case SCAN_SET_CHANNEL:
1136                         ieee80211_scan_state_set_channel(local, &next_delay);
1137                         break;
1138                 case SCAN_SEND_PROBE:
1139                         ieee80211_scan_state_send_probe(local, &next_delay);
1140                         break;
1141                 case SCAN_SUSPEND:
1142                         ieee80211_scan_state_suspend(local, &next_delay);
1143                         break;
1144                 case SCAN_RESUME:
1145                         ieee80211_scan_state_resume(local, &next_delay);
1146                         break;
1147                 case SCAN_ABORT:
1148                         aborted = true;
1149                         goto out_complete;
1150                 }
1151         } while (next_delay == 0);
1152
1153         ieee80211_queue_delayed_work(&local->hw, &local->scan_work, next_delay);
1154         goto out;
1155
1156 out_complete:
1157         __ieee80211_scan_completed(&local->hw, aborted);
1158 out:
1159         mutex_unlock(&local->mtx);
1160 }
1161
1162 int ieee80211_request_scan(struct ieee80211_sub_if_data *sdata,
1163                            struct cfg80211_scan_request *req)
1164 {
1165         int res;
1166
1167         mutex_lock(&sdata->local->mtx);
1168         res = __ieee80211_start_scan(sdata, req);
1169         mutex_unlock(&sdata->local->mtx);
1170
1171         return res;
1172 }
1173
1174 int ieee80211_request_ibss_scan(struct ieee80211_sub_if_data *sdata,
1175                                 const u8 *ssid, u8 ssid_len,
1176                                 struct ieee80211_channel **channels,
1177                                 unsigned int n_channels,
1178                                 enum nl80211_bss_scan_width scan_width)
1179 {
1180         struct ieee80211_local *local = sdata->local;
1181         int ret = -EBUSY, i, n_ch = 0;
1182         enum nl80211_band band;
1183
1184         mutex_lock(&local->mtx);
1185
1186         /* busy scanning */
1187         if (local->scan_req)
1188                 goto unlock;
1189
1190         /* fill internal scan request */
1191         if (!channels) {
1192                 int max_n;
1193
1194                 for (band = 0; band < NUM_NL80211_BANDS; band++) {
1195                         if (!local->hw.wiphy->bands[band] ||
1196                             band == NL80211_BAND_6GHZ)
1197                                 continue;
1198
1199                         max_n = local->hw.wiphy->bands[band]->n_channels;
1200                         for (i = 0; i < max_n; i++) {
1201                                 struct ieee80211_channel *tmp_ch =
1202                                     &local->hw.wiphy->bands[band]->channels[i];
1203
1204                                 if (tmp_ch->flags & (IEEE80211_CHAN_NO_IR |
1205                                                      IEEE80211_CHAN_DISABLED))
1206                                         continue;
1207
1208                                 local->int_scan_req->channels[n_ch] = tmp_ch;
1209                                 n_ch++;
1210                         }
1211                 }
1212
1213                 if (WARN_ON_ONCE(n_ch == 0))
1214                         goto unlock;
1215
1216                 local->int_scan_req->n_channels = n_ch;
1217         } else {
1218                 for (i = 0; i < n_channels; i++) {
1219                         if (channels[i]->flags & (IEEE80211_CHAN_NO_IR |
1220                                                   IEEE80211_CHAN_DISABLED))
1221                                 continue;
1222
1223                         local->int_scan_req->channels[n_ch] = channels[i];
1224                         n_ch++;
1225                 }
1226
1227                 if (WARN_ON_ONCE(n_ch == 0))
1228                         goto unlock;
1229
1230                 local->int_scan_req->n_channels = n_ch;
1231         }
1232
1233         local->int_scan_req->ssids = &local->scan_ssid;
1234         local->int_scan_req->n_ssids = 1;
1235         local->int_scan_req->scan_width = scan_width;
1236         memcpy(local->int_scan_req->ssids[0].ssid, ssid, IEEE80211_MAX_SSID_LEN);
1237         local->int_scan_req->ssids[0].ssid_len = ssid_len;
1238
1239         ret = __ieee80211_start_scan(sdata, sdata->local->int_scan_req);
1240  unlock:
1241         mutex_unlock(&local->mtx);
1242         return ret;
1243 }
1244
1245 /*
1246  * Only call this function when a scan can't be queued -- under RTNL.
1247  */
1248 void ieee80211_scan_cancel(struct ieee80211_local *local)
1249 {
1250         /*
1251          * We are canceling software scan, or deferred scan that was not
1252          * yet really started (see __ieee80211_start_scan ).
1253          *
1254          * Regarding hardware scan:
1255          * - we can not call  __ieee80211_scan_completed() as when
1256          *   SCAN_HW_SCANNING bit is set this function change
1257          *   local->hw_scan_req to operate on 5G band, what race with
1258          *   driver which can use local->hw_scan_req
1259          *
1260          * - we can not cancel scan_work since driver can schedule it
1261          *   by ieee80211_scan_completed(..., true) to finish scan
1262          *
1263          * Hence we only call the cancel_hw_scan() callback, but the low-level
1264          * driver is still responsible for calling ieee80211_scan_completed()
1265          * after the scan was completed/aborted.
1266          */
1267
1268         mutex_lock(&local->mtx);
1269         if (!local->scan_req)
1270                 goto out;
1271
1272         /*
1273          * We have a scan running and the driver already reported completion,
1274          * but the worker hasn't run yet or is stuck on the mutex - mark it as
1275          * cancelled.
1276          */
1277         if (test_bit(SCAN_HW_SCANNING, &local->scanning) &&
1278             test_bit(SCAN_COMPLETED, &local->scanning)) {
1279                 set_bit(SCAN_HW_CANCELLED, &local->scanning);
1280                 goto out;
1281         }
1282
1283         if (test_bit(SCAN_HW_SCANNING, &local->scanning)) {
1284                 /*
1285                  * Make sure that __ieee80211_scan_completed doesn't trigger a
1286                  * scan on another band.
1287                  */
1288                 set_bit(SCAN_HW_CANCELLED, &local->scanning);
1289                 if (local->ops->cancel_hw_scan)
1290                         drv_cancel_hw_scan(local,
1291                                 rcu_dereference_protected(local->scan_sdata,
1292                                                 lockdep_is_held(&local->mtx)));
1293                 goto out;
1294         }
1295
1296         /*
1297          * If the work is currently running, it must be blocked on
1298          * the mutex, but we'll set scan_sdata = NULL and it'll
1299          * simply exit once it acquires the mutex.
1300          */
1301         cancel_delayed_work(&local->scan_work);
1302         /* and clean up */
1303         memset(&local->scan_info, 0, sizeof(local->scan_info));
1304         __ieee80211_scan_completed(&local->hw, true);
1305 out:
1306         mutex_unlock(&local->mtx);
1307 }
1308
1309 int __ieee80211_request_sched_scan_start(struct ieee80211_sub_if_data *sdata,
1310                                         struct cfg80211_sched_scan_request *req)
1311 {
1312         struct ieee80211_local *local = sdata->local;
1313         struct ieee80211_scan_ies sched_scan_ies = {};
1314         struct cfg80211_chan_def chandef;
1315         int ret, i, iebufsz, num_bands = 0;
1316         u32 rate_masks[NUM_NL80211_BANDS] = {};
1317         u8 bands_used = 0;
1318         u8 *ie;
1319         u32 flags = 0;
1320
1321         iebufsz = local->scan_ies_len + req->ie_len;
1322
1323         lockdep_assert_held(&local->mtx);
1324
1325         if (!local->ops->sched_scan_start)
1326                 return -ENOTSUPP;
1327
1328         for (i = 0; i < NUM_NL80211_BANDS; i++) {
1329                 if (local->hw.wiphy->bands[i]) {
1330                         bands_used |= BIT(i);
1331                         rate_masks[i] = (u32) -1;
1332                         num_bands++;
1333                 }
1334         }
1335
1336         if (req->flags & NL80211_SCAN_FLAG_MIN_PREQ_CONTENT)
1337                 flags |= IEEE80211_PROBE_FLAG_MIN_CONTENT;
1338
1339         ie = kcalloc(iebufsz, num_bands, GFP_KERNEL);
1340         if (!ie) {
1341                 ret = -ENOMEM;
1342                 goto out;
1343         }
1344
1345         ieee80211_prepare_scan_chandef(&chandef, req->scan_width);
1346
1347         ieee80211_build_preq_ies(sdata, ie, num_bands * iebufsz,
1348                                  &sched_scan_ies, req->ie,
1349                                  req->ie_len, bands_used, rate_masks, &chandef,
1350                                  flags);
1351
1352         ret = drv_sched_scan_start(local, sdata, req, &sched_scan_ies);
1353         if (ret == 0) {
1354                 rcu_assign_pointer(local->sched_scan_sdata, sdata);
1355                 rcu_assign_pointer(local->sched_scan_req, req);
1356         }
1357
1358         kfree(ie);
1359
1360 out:
1361         if (ret) {
1362                 /* Clean in case of failure after HW restart or upon resume. */
1363                 RCU_INIT_POINTER(local->sched_scan_sdata, NULL);
1364                 RCU_INIT_POINTER(local->sched_scan_req, NULL);
1365         }
1366
1367         return ret;
1368 }
1369
1370 int ieee80211_request_sched_scan_start(struct ieee80211_sub_if_data *sdata,
1371                                        struct cfg80211_sched_scan_request *req)
1372 {
1373         struct ieee80211_local *local = sdata->local;
1374         int ret;
1375
1376         mutex_lock(&local->mtx);
1377
1378         if (rcu_access_pointer(local->sched_scan_sdata)) {
1379                 mutex_unlock(&local->mtx);
1380                 return -EBUSY;
1381         }
1382
1383         ret = __ieee80211_request_sched_scan_start(sdata, req);
1384
1385         mutex_unlock(&local->mtx);
1386         return ret;
1387 }
1388
1389 int ieee80211_request_sched_scan_stop(struct ieee80211_local *local)
1390 {
1391         struct ieee80211_sub_if_data *sched_scan_sdata;
1392         int ret = -ENOENT;
1393
1394         mutex_lock(&local->mtx);
1395
1396         if (!local->ops->sched_scan_stop) {
1397                 ret = -ENOTSUPP;
1398                 goto out;
1399         }
1400
1401         /* We don't want to restart sched scan anymore. */
1402         RCU_INIT_POINTER(local->sched_scan_req, NULL);
1403
1404         sched_scan_sdata = rcu_dereference_protected(local->sched_scan_sdata,
1405                                                 lockdep_is_held(&local->mtx));
1406         if (sched_scan_sdata) {
1407                 ret = drv_sched_scan_stop(local, sched_scan_sdata);
1408                 if (!ret)
1409                         RCU_INIT_POINTER(local->sched_scan_sdata, NULL);
1410         }
1411 out:
1412         mutex_unlock(&local->mtx);
1413
1414         return ret;
1415 }
1416
1417 void ieee80211_sched_scan_results(struct ieee80211_hw *hw)
1418 {
1419         struct ieee80211_local *local = hw_to_local(hw);
1420
1421         trace_api_sched_scan_results(local);
1422
1423         cfg80211_sched_scan_results(hw->wiphy, 0);
1424 }
1425 EXPORT_SYMBOL(ieee80211_sched_scan_results);
1426
1427 void ieee80211_sched_scan_end(struct ieee80211_local *local)
1428 {
1429         mutex_lock(&local->mtx);
1430
1431         if (!rcu_access_pointer(local->sched_scan_sdata)) {
1432                 mutex_unlock(&local->mtx);
1433                 return;
1434         }
1435
1436         RCU_INIT_POINTER(local->sched_scan_sdata, NULL);
1437
1438         /* If sched scan was aborted by the driver. */
1439         RCU_INIT_POINTER(local->sched_scan_req, NULL);
1440
1441         mutex_unlock(&local->mtx);
1442
1443         cfg80211_sched_scan_stopped(local->hw.wiphy, 0);
1444 }
1445
1446 void ieee80211_sched_scan_stopped_work(struct work_struct *work)
1447 {
1448         struct ieee80211_local *local =
1449                 container_of(work, struct ieee80211_local,
1450                              sched_scan_stopped_work);
1451
1452         ieee80211_sched_scan_end(local);
1453 }
1454
1455 void ieee80211_sched_scan_stopped(struct ieee80211_hw *hw)
1456 {
1457         struct ieee80211_local *local = hw_to_local(hw);
1458
1459         trace_api_sched_scan_stopped(local);
1460
1461         /*
1462          * this shouldn't really happen, so for simplicity
1463          * simply ignore it, and let mac80211 reconfigure
1464          * the sched scan later on.
1465          */
1466         if (local->in_reconfig)
1467                 return;
1468
1469         schedule_work(&local->sched_scan_stopped_work);
1470 }
1471 EXPORT_SYMBOL(ieee80211_sched_scan_stopped);