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