root/net/mac80211/scan.c

DEFINITIONS

1. ieee80211_rx_bss_put
2. is_uapsd_supported
3. ieee80211_update_bss_from_elems
4. ieee80211_bss_info_update
5. ieee80211_scan_accept_presp
6. ieee80211_scan_rx
7. ieee80211_prepare_scan_chandef
8. ieee80211_prep_hw_scan
9. __ieee80211_scan_completed
10. ieee80211_scan_completed
11. ieee80211_start_sw_scan
12. __ieee80211_can_leave_ch
13. ieee80211_can_scan
14. ieee80211_run_deferred_scan
15. ieee80211_send_scan_probe_req
16. ieee80211_scan_state_send_probe
17. __ieee80211_start_scan
18. ieee80211_scan_get_channel_time
19. ieee80211_scan_state_decision
20. ieee80211_scan_state_set_channel
21. ieee80211_scan_state_suspend
22. ieee80211_scan_state_resume
23. ieee80211_scan_work
24. ieee80211_request_scan
25. ieee80211_request_ibss_scan
26. ieee80211_scan_cancel
27. __ieee80211_request_sched_scan_start
28. ieee80211_request_sched_scan_start
29. ieee80211_request_sched_scan_stop
30. ieee80211_sched_scan_results
31. ieee80211_sched_scan_end
32. ieee80211_sched_scan_stopped_work
33. ieee80211_sched_scan_stopped

   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) 2018-2019 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 
 137 struct ieee80211_bss *
 138 ieee80211_bss_info_update(struct ieee80211_local *local,
 139                           struct ieee80211_rx_status *rx_status,
 140                           struct ieee80211_mgmt *mgmt, size_t len,
 141                           struct ieee80211_channel *channel)
 142 {
 143         bool beacon = ieee80211_is_beacon(mgmt->frame_control);
 144         struct cfg80211_bss *cbss, *non_tx_cbss;
 145         struct ieee80211_bss *bss, *non_tx_bss;
 146         struct cfg80211_inform_bss bss_meta = {
 147                 .boottime_ns = rx_status->boottime_ns,
 148         };
 149         bool signal_valid;
 150         struct ieee80211_sub_if_data *scan_sdata;
 151         struct ieee802_11_elems elems;
 152         size_t baselen;
 153         u8 *elements;
 154 
 155         if (rx_status->flag & RX_FLAG_NO_SIGNAL_VAL)
 156                 bss_meta.signal = 0; /* invalid signal indication */
 157         else if (ieee80211_hw_check(&local->hw, SIGNAL_DBM))
 158                 bss_meta.signal = rx_status->signal * 100;
 159         else if (ieee80211_hw_check(&local->hw, SIGNAL_UNSPEC))
 160                 bss_meta.signal = (rx_status->signal * 100) / local->hw.max_signal;
 161 
 162         bss_meta.scan_width = NL80211_BSS_CHAN_WIDTH_20;
 163         if (rx_status->bw == RATE_INFO_BW_5)
 164                 bss_meta.scan_width = NL80211_BSS_CHAN_WIDTH_5;
 165         else if (rx_status->bw == RATE_INFO_BW_10)
 166                 bss_meta.scan_width = NL80211_BSS_CHAN_WIDTH_10;
 167 
 168         bss_meta.chan = channel;
 169 
 170         rcu_read_lock();
 171         scan_sdata = rcu_dereference(local->scan_sdata);
 172         if (scan_sdata && scan_sdata->vif.type == NL80211_IFTYPE_STATION &&
 173             scan_sdata->vif.bss_conf.assoc &&
 174             ieee80211_have_rx_timestamp(rx_status)) {
 175                 bss_meta.parent_tsf =
 176                         ieee80211_calculate_rx_timestamp(local, rx_status,
 177                                                          len + FCS_LEN, 24);
 178                 ether_addr_copy(bss_meta.parent_bssid,
 179                                 scan_sdata->vif.bss_conf.bssid);
 180         }
 181         rcu_read_unlock();
 182 
 183         cbss = cfg80211_inform_bss_frame_data(local->hw.wiphy, &bss_meta,
 184                                               mgmt, len, GFP_ATOMIC);
 185         if (!cbss)
 186                 return NULL;
 187 
 188         if (ieee80211_is_probe_resp(mgmt->frame_control)) {
 189                 elements = mgmt->u.probe_resp.variable;
 190                 baselen = offsetof(struct ieee80211_mgmt,
 191                                    u.probe_resp.variable);
 192         } else {
 193                 baselen = offsetof(struct ieee80211_mgmt, u.beacon.variable);
 194                 elements = mgmt->u.beacon.variable;
 195         }
 196 
 197         if (baselen > len)
 198                 return NULL;
 199 
 200         ieee802_11_parse_elems(elements, len - baselen, false, &elems,
 201                                mgmt->bssid, cbss->bssid);
 202 
 203         /* In case the signal is invalid update the status */
 204         signal_valid = abs(channel->center_freq - cbss->channel->center_freq)
 205                 <= local->hw.wiphy->max_adj_channel_rssi_comp;
 206         if (!signal_valid)
 207                 rx_status->flag |= RX_FLAG_NO_SIGNAL_VAL;
 208 
 209         bss = (void *)cbss->priv;
 210         ieee80211_update_bss_from_elems(local, bss, &elems, rx_status, beacon);
 211 
 212         list_for_each_entry(non_tx_cbss, &cbss->nontrans_list, nontrans_list) {
 213                 non_tx_bss = (void *)non_tx_cbss->priv;
 214 
 215                 ieee80211_update_bss_from_elems(local, non_tx_bss, &elems,
 216                                                 rx_status, beacon);
 217         }
 218 
 219         return bss;
 220 }
 221 
 222 static bool ieee80211_scan_accept_presp(struct ieee80211_sub_if_data *sdata,
 223                                         u32 scan_flags, const u8 *da)
 224 {
 225         if (!sdata)
 226                 return false;
 227         /* accept broadcast for OCE */
 228         if (scan_flags & NL80211_SCAN_FLAG_ACCEPT_BCAST_PROBE_RESP &&
 229             is_broadcast_ether_addr(da))
 230                 return true;
 231         if (scan_flags & NL80211_SCAN_FLAG_RANDOM_ADDR)
 232                 return true;
 233         return ether_addr_equal(da, sdata->vif.addr);
 234 }
 235 
 236 void ieee80211_scan_rx(struct ieee80211_local *local, struct sk_buff *skb)
 237 {
 238         struct ieee80211_rx_status *rx_status = IEEE80211_SKB_RXCB(skb);
 239         struct ieee80211_sub_if_data *sdata1, *sdata2;
 240         struct ieee80211_mgmt *mgmt = (void *)skb->data;
 241         struct ieee80211_bss *bss;
 242         struct ieee80211_channel *channel;
 243 
 244         if (skb->len < 24 ||
 245             (!ieee80211_is_probe_resp(mgmt->frame_control) &&
 246              !ieee80211_is_beacon(mgmt->frame_control)))
 247                 return;
 248 
 249         sdata1 = rcu_dereference(local->scan_sdata);
 250         sdata2 = rcu_dereference(local->sched_scan_sdata);
 251 
 252         if (likely(!sdata1 && !sdata2))
 253                 return;
 254 
 255         if (ieee80211_is_probe_resp(mgmt->frame_control)) {
 256                 struct cfg80211_scan_request *scan_req;
 257                 struct cfg80211_sched_scan_request *sched_scan_req;
 258                 u32 scan_req_flags = 0, sched_scan_req_flags = 0;
 259 
 260                 scan_req = rcu_dereference(local->scan_req);
 261                 sched_scan_req = rcu_dereference(local->sched_scan_req);
 262 
 263                 if (scan_req)
 264                         scan_req_flags = scan_req->flags;
 265 
 266                 if (sched_scan_req)
 267                         sched_scan_req_flags = sched_scan_req->flags;
 268 
 269                 /* ignore ProbeResp to foreign address or non-bcast (OCE)
 270                  * unless scanning with randomised address
 271                  */
 272                 if (!ieee80211_scan_accept_presp(sdata1, scan_req_flags,
 273                                                  mgmt->da) &&
 274                     !ieee80211_scan_accept_presp(sdata2, sched_scan_req_flags,
 275                                                  mgmt->da))
 276                         return;
 277         }
 278 
 279         channel = ieee80211_get_channel(local->hw.wiphy, rx_status->freq);
 280 
 281         if (!channel || channel->flags & IEEE80211_CHAN_DISABLED)
 282                 return;
 283 
 284         bss = ieee80211_bss_info_update(local, rx_status,
 285                                         mgmt, skb->len,
 286                                         channel);
 287         if (bss)
 288                 ieee80211_rx_bss_put(local, bss);
 289 }
 290 
 291 static void
 292 ieee80211_prepare_scan_chandef(struct cfg80211_chan_def *chandef,
 293                                enum nl80211_bss_scan_width scan_width)
 294 {
 295         memset(chandef, 0, sizeof(*chandef));
 296         switch (scan_width) {
 297         case NL80211_BSS_CHAN_WIDTH_5:
 298                 chandef->width = NL80211_CHAN_WIDTH_5;
 299                 break;
 300         case NL80211_BSS_CHAN_WIDTH_10:
 301                 chandef->width = NL80211_CHAN_WIDTH_10;
 302                 break;
 303         default:
 304                 chandef->width = NL80211_CHAN_WIDTH_20_NOHT;
 305                 break;
 306         }
 307 }
 308 
 309 /* return false if no more work */
 310 static bool ieee80211_prep_hw_scan(struct ieee80211_local *local)
 311 {
 312         struct cfg80211_scan_request *req;
 313         struct cfg80211_chan_def chandef;
 314         u8 bands_used = 0;
 315         int i, ielen, n_chans;
 316         u32 flags = 0;
 317 
 318         req = rcu_dereference_protected(local->scan_req,
 319                                         lockdep_is_held(&local->mtx));
 320 
 321         if (test_bit(SCAN_HW_CANCELLED, &local->scanning))
 322                 return false;
 323 
 324         if (ieee80211_hw_check(&local->hw, SINGLE_SCAN_ON_ALL_BANDS)) {
 325                 for (i = 0; i < req->n_channels; i++) {
 326                         local->hw_scan_req->req.channels[i] = req->channels[i];
 327                         bands_used |= BIT(req->channels[i]->band);
 328                 }
 329 
 330                 n_chans = req->n_channels;
 331         } else {
 332                 do {
 333                         if (local->hw_scan_band == NUM_NL80211_BANDS)
 334                                 return false;
 335 
 336                         n_chans = 0;
 337 
 338                         for (i = 0; i < req->n_channels; i++) {
 339                                 if (req->channels[i]->band !=
 340                                     local->hw_scan_band)
 341                                         continue;
 342                                 local->hw_scan_req->req.channels[n_chans] =
 343                                                         req->channels[i];
 344                                 n_chans++;
 345                                 bands_used |= BIT(req->channels[i]->band);
 346                         }
 347 
 348                         local->hw_scan_band++;
 349                 } while (!n_chans);
 350         }
 351 
 352         local->hw_scan_req->req.n_channels = n_chans;
 353         ieee80211_prepare_scan_chandef(&chandef, req->scan_width);
 354 
 355         if (req->flags & NL80211_SCAN_FLAG_MIN_PREQ_CONTENT)
 356                 flags |= IEEE80211_PROBE_FLAG_MIN_CONTENT;
 357 
 358         ielen = ieee80211_build_preq_ies(local,
 359                                          (u8 *)local->hw_scan_req->req.ie,
 360                                          local->hw_scan_ies_bufsize,
 361                                          &local->hw_scan_req->ies,
 362                                          req->ie, req->ie_len,
 363                                          bands_used, req->rates, &chandef,
 364                                          flags);
 365         local->hw_scan_req->req.ie_len = ielen;
 366         local->hw_scan_req->req.no_cck = req->no_cck;
 367         ether_addr_copy(local->hw_scan_req->req.mac_addr, req->mac_addr);
 368         ether_addr_copy(local->hw_scan_req->req.mac_addr_mask,
 369                         req->mac_addr_mask);
 370         ether_addr_copy(local->hw_scan_req->req.bssid, req->bssid);
 371 
 372         return true;
 373 }
 374 
 375 static void __ieee80211_scan_completed(struct ieee80211_hw *hw, bool aborted)
 376 {
 377         struct ieee80211_local *local = hw_to_local(hw);
 378         bool hw_scan = test_bit(SCAN_HW_SCANNING, &local->scanning);
 379         bool was_scanning = local->scanning;
 380         struct cfg80211_scan_request *scan_req;
 381         struct ieee80211_sub_if_data *scan_sdata;
 382         struct ieee80211_sub_if_data *sdata;
 383 
 384         lockdep_assert_held(&local->mtx);
 385 
 386         /*
 387          * It's ok to abort a not-yet-running scan (that
 388          * we have one at all will be verified by checking
 389          * local->scan_req next), but not to complete it
 390          * successfully.
 391          */
 392         if (WARN_ON(!local->scanning && !aborted))
 393                 aborted = true;
 394 
 395         if (WARN_ON(!local->scan_req))
 396                 return;
 397 
 398         if (hw_scan && !aborted &&
 399             !ieee80211_hw_check(&local->hw, SINGLE_SCAN_ON_ALL_BANDS) &&
 400             ieee80211_prep_hw_scan(local)) {
 401                 int rc;
 402 
 403                 rc = drv_hw_scan(local,
 404                         rcu_dereference_protected(local->scan_sdata,
 405                                                   lockdep_is_held(&local->mtx)),
 406                         local->hw_scan_req);
 407 
 408                 if (rc == 0)
 409                         return;
 410 
 411                 /* HW scan failed and is going to be reported as aborted,
 412                  * so clear old scan info.
 413                  */
 414                 memset(&local->scan_info, 0, sizeof(local->scan_info));
 415                 aborted = true;
 416         }
 417 
 418         kfree(local->hw_scan_req);
 419         local->hw_scan_req = NULL;
 420 
 421         scan_req = rcu_dereference_protected(local->scan_req,
 422                                              lockdep_is_held(&local->mtx));
 423 
 424         if (scan_req != local->int_scan_req) {
 425                 local->scan_info.aborted = aborted;
 426                 cfg80211_scan_done(scan_req, &local->scan_info);
 427         }
 428         RCU_INIT_POINTER(local->scan_req, NULL);
 429 
 430         scan_sdata = rcu_dereference_protected(local->scan_sdata,
 431                                                lockdep_is_held(&local->mtx));
 432         RCU_INIT_POINTER(local->scan_sdata, NULL);
 433 
 434         local->scanning = 0;
 435         local->scan_chandef.chan = NULL;
 436 
 437         /* Set power back to normal operating levels. */
 438         ieee80211_hw_config(local, 0);
 439 
 440         if (!hw_scan) {
 441                 ieee80211_configure_filter(local);
 442                 drv_sw_scan_complete(local, scan_sdata);
 443                 ieee80211_offchannel_return(local);
 444         }
 445 
 446         ieee80211_recalc_idle(local);
 447 
 448         ieee80211_mlme_notify_scan_completed(local);
 449         ieee80211_ibss_notify_scan_completed(local);
 450 
 451         /* Requeue all the work that might have been ignored while
 452          * the scan was in progress; if there was none this will
 453          * just be a no-op for the particular interface.
 454          */
 455         list_for_each_entry_rcu(sdata, &local->interfaces, list) {
 456                 if (ieee80211_sdata_running(sdata))
 457                         ieee80211_queue_work(&sdata->local->hw, &sdata->work);
 458         }
 459 
 460         if (was_scanning)
 461                 ieee80211_start_next_roc(local);
 462 }
 463 
 464 void ieee80211_scan_completed(struct ieee80211_hw *hw,
 465                               struct cfg80211_scan_info *info)
 466 {
 467         struct ieee80211_local *local = hw_to_local(hw);
 468 
 469         trace_api_scan_completed(local, info->aborted);
 470 
 471         set_bit(SCAN_COMPLETED, &local->scanning);
 472         if (info->aborted)
 473                 set_bit(SCAN_ABORTED, &local->scanning);
 474 
 475         memcpy(&local->scan_info, info, sizeof(*info));
 476 
 477         ieee80211_queue_delayed_work(&local->hw, &local->scan_work, 0);
 478 }
 479 EXPORT_SYMBOL(ieee80211_scan_completed);
 480 
 481 static int ieee80211_start_sw_scan(struct ieee80211_local *local,
 482                                    struct ieee80211_sub_if_data *sdata)
 483 {
 484         /* Software scan is not supported in multi-channel cases */
 485         if (local->use_chanctx)
 486                 return -EOPNOTSUPP;
 487 
 488         /*
 489          * Hardware/driver doesn't support hw_scan, so use software
 490          * scanning instead. First send a nullfunc frame with power save
 491          * bit on so that AP will buffer the frames for us while we are not
 492          * listening, then send probe requests to each channel and wait for
 493          * the responses. After all channels are scanned, tune back to the
 494          * original channel and send a nullfunc frame with power save bit
 495          * off to trigger the AP to send us all the buffered frames.
 496          *
 497          * Note that while local->sw_scanning is true everything else but
 498          * nullfunc frames and probe requests will be dropped in
 499          * ieee80211_tx_h_check_assoc().
 500          */
 501         drv_sw_scan_start(local, sdata, local->scan_addr);
 502 
 503         local->leave_oper_channel_time = jiffies;
 504         local->next_scan_state = SCAN_DECISION;
 505         local->scan_channel_idx = 0;
 506 
 507         ieee80211_offchannel_stop_vifs(local);
 508 
 509         /* ensure nullfunc is transmitted before leaving operating channel */
 510         ieee80211_flush_queues(local, NULL, false);
 511 
 512         ieee80211_configure_filter(local);
 513 
 514         /* We need to set power level at maximum rate for scanning. */
 515         ieee80211_hw_config(local, 0);
 516 
 517         ieee80211_queue_delayed_work(&local->hw,
 518                                      &local->scan_work, 0);
 519 
 520         return 0;
 521 }
 522 
 523 static bool __ieee80211_can_leave_ch(struct ieee80211_sub_if_data *sdata)
 524 {
 525         struct ieee80211_local *local = sdata->local;
 526         struct ieee80211_sub_if_data *sdata_iter;
 527 
 528         if (!ieee80211_is_radar_required(local))
 529                 return true;
 530 
 531         if (!regulatory_pre_cac_allowed(local->hw.wiphy))
 532                 return false;
 533 
 534         mutex_lock(&local->iflist_mtx);
 535         list_for_each_entry(sdata_iter, &local->interfaces, list) {
 536                 if (sdata_iter->wdev.cac_started) {
 537                         mutex_unlock(&local->iflist_mtx);
 538                         return false;
 539                 }
 540         }
 541         mutex_unlock(&local->iflist_mtx);
 542 
 543         return true;
 544 }
 545 
 546 static bool ieee80211_can_scan(struct ieee80211_local *local,
 547                                struct ieee80211_sub_if_data *sdata)
 548 {
 549         if (!__ieee80211_can_leave_ch(sdata))
 550                 return false;
 551 
 552         if (!list_empty(&local->roc_list))
 553                 return false;
 554 
 555         if (sdata->vif.type == NL80211_IFTYPE_STATION &&
 556             sdata->u.mgd.flags & IEEE80211_STA_CONNECTION_POLL)
 557                 return false;
 558 
 559         return true;
 560 }
 561 
 562 void ieee80211_run_deferred_scan(struct ieee80211_local *local)
 563 {
 564         lockdep_assert_held(&local->mtx);
 565 
 566         if (!local->scan_req || local->scanning)
 567                 return;
 568 
 569         if (!ieee80211_can_scan(local,
 570                                 rcu_dereference_protected(
 571                                         local->scan_sdata,
 572                                         lockdep_is_held(&local->mtx))))
 573                 return;
 574 
 575         ieee80211_queue_delayed_work(&local->hw, &local->scan_work,
 576                                      round_jiffies_relative(0));
 577 }
 578 
 579 static void ieee80211_send_scan_probe_req(struct ieee80211_sub_if_data *sdata,
 580                                           const u8 *src, const u8 *dst,
 581                                           const u8 *ssid, size_t ssid_len,
 582                                           const u8 *ie, size_t ie_len,
 583                                           u32 ratemask, u32 flags, u32 tx_flags,
 584                                           struct ieee80211_channel *channel)
 585 {
 586         struct sk_buff *skb;
 587         u32 txdata_flags = 0;
 588 
 589         skb = ieee80211_build_probe_req(sdata, src, dst, ratemask, channel,
 590                                         ssid, ssid_len,
 591                                         ie, ie_len, flags);
 592 
 593         if (skb) {
 594                 if (flags & IEEE80211_PROBE_FLAG_RANDOM_SN) {
 595                         struct ieee80211_hdr *hdr = (void *)skb->data;
 596                         u16 sn = get_random_u32();
 597 
 598                         txdata_flags |= IEEE80211_TX_NO_SEQNO;
 599                         hdr->seq_ctrl =
 600                                 cpu_to_le16(IEEE80211_SN_TO_SEQ(sn));
 601                 }
 602                 IEEE80211_SKB_CB(skb)->flags |= tx_flags;
 603                 ieee80211_tx_skb_tid_band(sdata, skb, 7, channel->band,
 604                                           txdata_flags);
 605         }
 606 }
 607 
 608 static void ieee80211_scan_state_send_probe(struct ieee80211_local *local,
 609                                             unsigned long *next_delay)
 610 {
 611         int i;
 612         struct ieee80211_sub_if_data *sdata;
 613         struct cfg80211_scan_request *scan_req;
 614         enum nl80211_band band = local->hw.conf.chandef.chan->band;
 615         u32 flags = 0, tx_flags;
 616 
 617         scan_req = rcu_dereference_protected(local->scan_req,
 618                                              lockdep_is_held(&local->mtx));
 619 
 620         tx_flags = IEEE80211_TX_INTFL_OFFCHAN_TX_OK;
 621         if (scan_req->no_cck)
 622                 tx_flags |= IEEE80211_TX_CTL_NO_CCK_RATE;
 623         if (scan_req->flags & NL80211_SCAN_FLAG_MIN_PREQ_CONTENT)
 624                 flags |= IEEE80211_PROBE_FLAG_MIN_CONTENT;
 625         if (scan_req->flags & NL80211_SCAN_FLAG_RANDOM_SN)
 626                 flags |= IEEE80211_PROBE_FLAG_RANDOM_SN;
 627 
 628         sdata = rcu_dereference_protected(local->scan_sdata,
 629                                           lockdep_is_held(&local->mtx));
 630 
 631         for (i = 0; i < scan_req->n_ssids; i++)
 632                 ieee80211_send_scan_probe_req(
 633                         sdata, local->scan_addr, scan_req->bssid,
 634                         scan_req->ssids[i].ssid, scan_req->ssids[i].ssid_len,
 635                         scan_req->ie, scan_req->ie_len,
 636                         scan_req->rates[band], flags,
 637                         tx_flags, local->hw.conf.chandef.chan);
 638 
 639         /*
 640          * After sending probe requests, wait for probe responses
 641          * on the channel.
 642          */
 643         *next_delay = IEEE80211_CHANNEL_TIME;
 644         local->next_scan_state = SCAN_DECISION;
 645 }
 646 
 647 static int __ieee80211_start_scan(struct ieee80211_sub_if_data *sdata,
 648                                   struct cfg80211_scan_request *req)
 649 {
 650         struct ieee80211_local *local = sdata->local;
 651         bool hw_scan = local->ops->hw_scan;
 652         int rc;
 653 
 654         lockdep_assert_held(&local->mtx);
 655 
 656         if (local->scan_req)
 657                 return -EBUSY;
 658 
 659         if (!__ieee80211_can_leave_ch(sdata))
 660                 return -EBUSY;
 661 
 662         if (!ieee80211_can_scan(local, sdata)) {
 663                 /* wait for the work to finish/time out */
 664                 rcu_assign_pointer(local->scan_req, req);
 665                 rcu_assign_pointer(local->scan_sdata, sdata);
 666                 return 0;
 667         }
 668 
 669  again:
 670         if (hw_scan) {
 671                 u8 *ies;
 672 
 673                 local->hw_scan_ies_bufsize = local->scan_ies_len + req->ie_len;
 674 
 675                 if (ieee80211_hw_check(&local->hw, SINGLE_SCAN_ON_ALL_BANDS)) {
 676                         int i, n_bands = 0;
 677                         u8 bands_counted = 0;
 678 
 679                         for (i = 0; i < req->n_channels; i++) {
 680                                 if (bands_counted & BIT(req->channels[i]->band))
 681                                         continue;
 682                                 bands_counted |= BIT(req->channels[i]->band);
 683                                 n_bands++;
 684                         }
 685 
 686                         local->hw_scan_ies_bufsize *= n_bands;
 687                 }
 688 
 689                 local->hw_scan_req = kmalloc(
 690                                 sizeof(*local->hw_scan_req) +
 691                                 req->n_channels * sizeof(req->channels[0]) +
 692                                 local->hw_scan_ies_bufsize, GFP_KERNEL);
 693                 if (!local->hw_scan_req)
 694                         return -ENOMEM;
 695 
 696                 local->hw_scan_req->req.ssids = req->ssids;
 697                 local->hw_scan_req->req.n_ssids = req->n_ssids;
 698                 ies = (u8 *)local->hw_scan_req +
 699                         sizeof(*local->hw_scan_req) +
 700                         req->n_channels * sizeof(req->channels[0]);
 701                 local->hw_scan_req->req.ie = ies;
 702                 local->hw_scan_req->req.flags = req->flags;
 703                 eth_broadcast_addr(local->hw_scan_req->req.bssid);
 704                 local->hw_scan_req->req.duration = req->duration;
 705                 local->hw_scan_req->req.duration_mandatory =
 706                         req->duration_mandatory;
 707 
 708                 local->hw_scan_band = 0;
 709 
 710                 /*
 711                  * After allocating local->hw_scan_req, we must
 712                  * go through until ieee80211_prep_hw_scan(), so
 713                  * anything that might be changed here and leave
 714                  * this function early must not go after this
 715                  * allocation.
 716                  */
 717         }
 718 
 719         rcu_assign_pointer(local->scan_req, req);
 720         rcu_assign_pointer(local->scan_sdata, sdata);
 721 
 722         if (req->flags & NL80211_SCAN_FLAG_RANDOM_ADDR)
 723                 get_random_mask_addr(local->scan_addr,
 724                                      req->mac_addr,
 725                                      req->mac_addr_mask);
 726         else
 727                 memcpy(local->scan_addr, sdata->vif.addr, ETH_ALEN);
 728 
 729         if (hw_scan) {
 730                 __set_bit(SCAN_HW_SCANNING, &local->scanning);
 731         } else if ((req->n_channels == 1) &&
 732                    (req->channels[0] == local->_oper_chandef.chan)) {
 733                 /*
 734                  * If we are scanning only on the operating channel
 735                  * then we do not need to stop normal activities
 736                  */
 737                 unsigned long next_delay;
 738 
 739                 __set_bit(SCAN_ONCHANNEL_SCANNING, &local->scanning);
 740 
 741                 ieee80211_recalc_idle(local);
 742 
 743                 /* Notify driver scan is starting, keep order of operations
 744                  * same as normal software scan, in case that matters. */
 745                 drv_sw_scan_start(local, sdata, local->scan_addr);
 746 
 747                 ieee80211_configure_filter(local); /* accept probe-responses */
 748 
 749                 /* We need to ensure power level is at max for scanning. */
 750                 ieee80211_hw_config(local, 0);
 751 
 752                 if ((req->channels[0]->flags & (IEEE80211_CHAN_NO_IR |
 753                                                 IEEE80211_CHAN_RADAR)) ||
 754                     !req->n_ssids) {
 755                         next_delay = IEEE80211_PASSIVE_CHANNEL_TIME;
 756                 } else {
 757                         ieee80211_scan_state_send_probe(local, &next_delay);
 758                         next_delay = IEEE80211_CHANNEL_TIME;
 759                 }
 760 
 761                 /* Now, just wait a bit and we are all done! */
 762                 ieee80211_queue_delayed_work(&local->hw, &local->scan_work,
 763                                              next_delay);
 764                 return 0;
 765         } else {
 766                 /* Do normal software scan */
 767                 __set_bit(SCAN_SW_SCANNING, &local->scanning);
 768         }
 769 
 770         ieee80211_recalc_idle(local);
 771 
 772         if (hw_scan) {
 773                 WARN_ON(!ieee80211_prep_hw_scan(local));
 774                 rc = drv_hw_scan(local, sdata, local->hw_scan_req);
 775         } else {
 776                 rc = ieee80211_start_sw_scan(local, sdata);
 777         }
 778 
 779         if (rc) {
 780                 kfree(local->hw_scan_req);
 781                 local->hw_scan_req = NULL;
 782                 local->scanning = 0;
 783 
 784                 ieee80211_recalc_idle(local);
 785 
 786                 local->scan_req = NULL;
 787                 RCU_INIT_POINTER(local->scan_sdata, NULL);
 788         }
 789 
 790         if (hw_scan && rc == 1) {
 791                 /*
 792                  * we can't fall back to software for P2P-GO
 793                  * as it must update NoA etc.
 794                  */
 795                 if (ieee80211_vif_type_p2p(&sdata->vif) ==
 796                                 NL80211_IFTYPE_P2P_GO)
 797                         return -EOPNOTSUPP;
 798                 hw_scan = false;
 799                 goto again;
 800         }
 801 
 802         return rc;
 803 }
 804 
 805 static unsigned long
 806 ieee80211_scan_get_channel_time(struct ieee80211_channel *chan)
 807 {
 808         /*
 809          * TODO: channel switching also consumes quite some time,
 810          * add that delay as well to get a better estimation
 811          */
 812         if (chan->flags & (IEEE80211_CHAN_NO_IR | IEEE80211_CHAN_RADAR))
 813                 return IEEE80211_PASSIVE_CHANNEL_TIME;
 814         return IEEE80211_PROBE_DELAY + IEEE80211_CHANNEL_TIME;
 815 }
 816 
 817 static void ieee80211_scan_state_decision(struct ieee80211_local *local,
 818                                           unsigned long *next_delay)
 819 {
 820         bool associated = false;
 821         bool tx_empty = true;
 822         bool bad_latency;
 823         struct ieee80211_sub_if_data *sdata;
 824         struct ieee80211_channel *next_chan;
 825         enum mac80211_scan_state next_scan_state;
 826         struct cfg80211_scan_request *scan_req;
 827 
 828         /*
 829          * check if at least one STA interface is associated,
 830          * check if at least one STA interface has pending tx frames
 831          * and grab the lowest used beacon interval
 832          */
 833         mutex_lock(&local->iflist_mtx);
 834         list_for_each_entry(sdata, &local->interfaces, list) {
 835                 if (!ieee80211_sdata_running(sdata))
 836                         continue;
 837 
 838                 if (sdata->vif.type == NL80211_IFTYPE_STATION) {
 839                         if (sdata->u.mgd.associated) {
 840                                 associated = true;
 841 
 842                                 if (!qdisc_all_tx_empty(sdata->dev)) {
 843                                         tx_empty = false;
 844                                         break;
 845                                 }
 846                         }
 847                 }
 848         }
 849         mutex_unlock(&local->iflist_mtx);
 850 
 851         scan_req = rcu_dereference_protected(local->scan_req,
 852                                              lockdep_is_held(&local->mtx));
 853 
 854         next_chan = scan_req->channels[local->scan_channel_idx];
 855 
 856         /*
 857          * we're currently scanning a different channel, let's
 858          * see if we can scan another channel without interfering
 859          * with the current traffic situation.
 860          *
 861          * Keep good latency, do not stay off-channel more than 125 ms.
 862          */
 863 
 864         bad_latency = time_after(jiffies +
 865                                  ieee80211_scan_get_channel_time(next_chan),
 866                                  local->leave_oper_channel_time + HZ / 8);
 867 
 868         if (associated && !tx_empty) {
 869                 if (scan_req->flags & NL80211_SCAN_FLAG_LOW_PRIORITY)
 870                         next_scan_state = SCAN_ABORT;
 871                 else
 872                         next_scan_state = SCAN_SUSPEND;
 873         } else if (associated && bad_latency) {
 874                 next_scan_state = SCAN_SUSPEND;
 875         } else {
 876                 next_scan_state = SCAN_SET_CHANNEL;
 877         }
 878 
 879         local->next_scan_state = next_scan_state;
 880 
 881         *next_delay = 0;
 882 }
 883 
 884 static void ieee80211_scan_state_set_channel(struct ieee80211_local *local,
 885                                              unsigned long *next_delay)
 886 {
 887         int skip;
 888         struct ieee80211_channel *chan;
 889         enum nl80211_bss_scan_width oper_scan_width;
 890         struct cfg80211_scan_request *scan_req;
 891 
 892         scan_req = rcu_dereference_protected(local->scan_req,
 893                                              lockdep_is_held(&local->mtx));
 894 
 895         skip = 0;
 896         chan = scan_req->channels[local->scan_channel_idx];
 897 
 898         local->scan_chandef.chan = chan;
 899         local->scan_chandef.center_freq1 = chan->center_freq;
 900         local->scan_chandef.center_freq2 = 0;
 901         switch (scan_req->scan_width) {
 902         case NL80211_BSS_CHAN_WIDTH_5:
 903                 local->scan_chandef.width = NL80211_CHAN_WIDTH_5;
 904                 break;
 905         case NL80211_BSS_CHAN_WIDTH_10:
 906                 local->scan_chandef.width = NL80211_CHAN_WIDTH_10;
 907                 break;
 908         case NL80211_BSS_CHAN_WIDTH_20:
 909                 /* If scanning on oper channel, use whatever channel-type
 910                  * is currently in use.
 911                  */
 912                 oper_scan_width = cfg80211_chandef_to_scan_width(
 913                                         &local->_oper_chandef);
 914                 if (chan == local->_oper_chandef.chan &&
 915                     oper_scan_width == scan_req->scan_width)
 916                         local->scan_chandef = local->_oper_chandef;
 917                 else
 918                         local->scan_chandef.width = NL80211_CHAN_WIDTH_20_NOHT;
 919                 break;
 920         }
 921 
 922         if (ieee80211_hw_config(local, IEEE80211_CONF_CHANGE_CHANNEL))
 923                 skip = 1;
 924 
 925         /* advance state machine to next channel/band */
 926         local->scan_channel_idx++;
 927 
 928         if (skip) {
 929                 /* if we skip this channel return to the decision state */
 930                 local->next_scan_state = SCAN_DECISION;
 931                 return;
 932         }
 933 
 934         /*
 935          * Probe delay is used to update the NAV, cf. 11.1.3.2.2
 936          * (which unfortunately doesn't say _why_ step a) is done,
 937          * but it waits for the probe delay or until a frame is
 938          * received - and the received frame would update the NAV).
 939          * For now, we do not support waiting until a frame is
 940          * received.
 941          *
 942          * In any case, it is not necessary for a passive scan.
 943          */
 944         if ((chan->flags & (IEEE80211_CHAN_NO_IR | IEEE80211_CHAN_RADAR)) ||
 945             !scan_req->n_ssids) {
 946                 *next_delay = IEEE80211_PASSIVE_CHANNEL_TIME;
 947                 local->next_scan_state = SCAN_DECISION;
 948                 return;
 949         }
 950 
 951         /* active scan, send probes */
 952         *next_delay = IEEE80211_PROBE_DELAY;
 953         local->next_scan_state = SCAN_SEND_PROBE;
 954 }
 955 
 956 static void ieee80211_scan_state_suspend(struct ieee80211_local *local,
 957                                          unsigned long *next_delay)
 958 {
 959         /* switch back to the operating channel */
 960         local->scan_chandef.chan = NULL;
 961         ieee80211_hw_config(local, IEEE80211_CONF_CHANGE_CHANNEL);
 962 
 963         /* disable PS */
 964         ieee80211_offchannel_return(local);
 965 
 966         *next_delay = HZ / 5;
 967         /* afterwards, resume scan & go to next channel */
 968         local->next_scan_state = SCAN_RESUME;
 969 }
 970 
 971 static void ieee80211_scan_state_resume(struct ieee80211_local *local,
 972                                         unsigned long *next_delay)
 973 {
 974         ieee80211_offchannel_stop_vifs(local);
 975 
 976         if (local->ops->flush) {
 977                 ieee80211_flush_queues(local, NULL, false);
 978                 *next_delay = 0;
 979         } else
 980                 *next_delay = HZ / 10;
 981 
 982         /* remember when we left the operating channel */
 983         local->leave_oper_channel_time = jiffies;
 984 
 985         /* advance to the next channel to be scanned */
 986         local->next_scan_state = SCAN_SET_CHANNEL;
 987 }
 988 
 989 void ieee80211_scan_work(struct work_struct *work)
 990 {
 991         struct ieee80211_local *local =
 992                 container_of(work, struct ieee80211_local, scan_work.work);
 993         struct ieee80211_sub_if_data *sdata;
 994         struct cfg80211_scan_request *scan_req;
 995         unsigned long next_delay = 0;
 996         bool aborted;
 997 
 998         mutex_lock(&local->mtx);
 999 
1000         if (!ieee80211_can_run_worker(local)) {
1001                 aborted = true;
1002                 goto out_complete;
1003         }
1004 
1005         sdata = rcu_dereference_protected(local->scan_sdata,
1006                                           lockdep_is_held(&local->mtx));
1007         scan_req = rcu_dereference_protected(local->scan_req,
1008                                              lockdep_is_held(&local->mtx));
1009 
1010         /* When scanning on-channel, the first-callback means completed. */
1011         if (test_bit(SCAN_ONCHANNEL_SCANNING, &local->scanning)) {
1012                 aborted = test_and_clear_bit(SCAN_ABORTED, &local->scanning);
1013                 goto out_complete;
1014         }
1015 
1016         if (test_and_clear_bit(SCAN_COMPLETED, &local->scanning)) {
1017                 aborted = test_and_clear_bit(SCAN_ABORTED, &local->scanning);
1018                 goto out_complete;
1019         }
1020 
1021         if (!sdata || !scan_req)
1022                 goto out;
1023 
1024         if (!local->scanning) {
1025                 int rc;
1026 
1027                 RCU_INIT_POINTER(local->scan_req, NULL);
1028                 RCU_INIT_POINTER(local->scan_sdata, NULL);
1029 
1030                 rc = __ieee80211_start_scan(sdata, scan_req);
1031                 if (rc) {
1032                         /* need to complete scan in cfg80211 */
1033                         rcu_assign_pointer(local->scan_req, scan_req);
1034                         aborted = true;
1035                         goto out_complete;
1036                 } else
1037                         goto out;
1038         }
1039 
1040         /*
1041          * as long as no delay is required advance immediately
1042          * without scheduling a new work
1043          */
1044         do {
1045                 if (!ieee80211_sdata_running(sdata)) {
1046                         aborted = true;
1047                         goto out_complete;
1048                 }
1049 
1050                 switch (local->next_scan_state) {
1051                 case SCAN_DECISION:
1052                         /* if no more bands/channels left, complete scan */
1053                         if (local->scan_channel_idx >= scan_req->n_channels) {
1054                                 aborted = false;
1055                                 goto out_complete;
1056                         }
1057                         ieee80211_scan_state_decision(local, &next_delay);
1058                         break;
1059                 case SCAN_SET_CHANNEL:
1060                         ieee80211_scan_state_set_channel(local, &next_delay);
1061                         break;
1062                 case SCAN_SEND_PROBE:
1063                         ieee80211_scan_state_send_probe(local, &next_delay);
1064                         break;
1065                 case SCAN_SUSPEND:
1066                         ieee80211_scan_state_suspend(local, &next_delay);
1067                         break;
1068                 case SCAN_RESUME:
1069                         ieee80211_scan_state_resume(local, &next_delay);
1070                         break;
1071                 case SCAN_ABORT:
1072                         aborted = true;
1073                         goto out_complete;
1074                 }
1075         } while (next_delay == 0);
1076 
1077         ieee80211_queue_delayed_work(&local->hw, &local->scan_work, next_delay);
1078         goto out;
1079 
1080 out_complete:
1081         __ieee80211_scan_completed(&local->hw, aborted);
1082 out:
1083         mutex_unlock(&local->mtx);
1084 }
1085 
1086 int ieee80211_request_scan(struct ieee80211_sub_if_data *sdata,
1087                            struct cfg80211_scan_request *req)
1088 {
1089         int res;
1090 
1091         mutex_lock(&sdata->local->mtx);
1092         res = __ieee80211_start_scan(sdata, req);
1093         mutex_unlock(&sdata->local->mtx);
1094 
1095         return res;
1096 }
1097 
1098 int ieee80211_request_ibss_scan(struct ieee80211_sub_if_data *sdata,
1099                                 const u8 *ssid, u8 ssid_len,
1100                                 struct ieee80211_channel **channels,
1101                                 unsigned int n_channels,
1102                                 enum nl80211_bss_scan_width scan_width)
1103 {
1104         struct ieee80211_local *local = sdata->local;
1105         int ret = -EBUSY, i, n_ch = 0;
1106         enum nl80211_band band;
1107 
1108         mutex_lock(&local->mtx);
1109 
1110         /* busy scanning */
1111         if (local->scan_req)
1112                 goto unlock;
1113 
1114         /* fill internal scan request */
1115         if (!channels) {
1116                 int max_n;
1117 
1118                 for (band = 0; band < NUM_NL80211_BANDS; band++) {
1119                         if (!local->hw.wiphy->bands[band])
1120                                 continue;
1121 
1122                         max_n = local->hw.wiphy->bands[band]->n_channels;
1123                         for (i = 0; i < max_n; i++) {
1124                                 struct ieee80211_channel *tmp_ch =
1125                                     &local->hw.wiphy->bands[band]->channels[i];
1126 
1127                                 if (tmp_ch->flags & (IEEE80211_CHAN_NO_IR |
1128                                                      IEEE80211_CHAN_DISABLED))
1129                                         continue;
1130 
1131                                 local->int_scan_req->channels[n_ch] = tmp_ch;
1132                                 n_ch++;
1133                         }
1134                 }
1135 
1136                 if (WARN_ON_ONCE(n_ch == 0))
1137                         goto unlock;
1138 
1139                 local->int_scan_req->n_channels = n_ch;
1140         } else {
1141                 for (i = 0; i < n_channels; i++) {
1142                         if (channels[i]->flags & (IEEE80211_CHAN_NO_IR |
1143                                                   IEEE80211_CHAN_DISABLED))
1144                                 continue;
1145 
1146                         local->int_scan_req->channels[n_ch] = channels[i];
1147                         n_ch++;
1148                 }
1149 
1150                 if (WARN_ON_ONCE(n_ch == 0))
1151                         goto unlock;
1152 
1153                 local->int_scan_req->n_channels = n_ch;
1154         }
1155 
1156         local->int_scan_req->ssids = &local->scan_ssid;
1157         local->int_scan_req->n_ssids = 1;
1158         local->int_scan_req->scan_width = scan_width;
1159         memcpy(local->int_scan_req->ssids[0].ssid, ssid, IEEE80211_MAX_SSID_LEN);
1160         local->int_scan_req->ssids[0].ssid_len = ssid_len;
1161 
1162         ret = __ieee80211_start_scan(sdata, sdata->local->int_scan_req);
1163  unlock:
1164         mutex_unlock(&local->mtx);
1165         return ret;
1166 }
1167 
1168 /*
1169  * Only call this function when a scan can't be queued -- under RTNL.
1170  */
1171 void ieee80211_scan_cancel(struct ieee80211_local *local)
1172 {
1173         /*
1174          * We are canceling software scan, or deferred scan that was not
1175          * yet really started (see __ieee80211_start_scan ).
1176          *
1177          * Regarding hardware scan:
1178          * - we can not call  __ieee80211_scan_completed() as when
1179          *   SCAN_HW_SCANNING bit is set this function change
1180          *   local->hw_scan_req to operate on 5G band, what race with
1181          *   driver which can use local->hw_scan_req
1182          *
1183          * - we can not cancel scan_work since driver can schedule it
1184          *   by ieee80211_scan_completed(..., true) to finish scan
1185          *
1186          * Hence we only call the cancel_hw_scan() callback, but the low-level
1187          * driver is still responsible for calling ieee80211_scan_completed()
1188          * after the scan was completed/aborted.
1189          */
1190 
1191         mutex_lock(&local->mtx);
1192         if (!local->scan_req)
1193                 goto out;
1194 
1195         /*
1196          * We have a scan running and the driver already reported completion,
1197          * but the worker hasn't run yet or is stuck on the mutex - mark it as
1198          * cancelled.
1199          */
1200         if (test_bit(SCAN_HW_SCANNING, &local->scanning) &&
1201             test_bit(SCAN_COMPLETED, &local->scanning)) {
1202                 set_bit(SCAN_HW_CANCELLED, &local->scanning);
1203                 goto out;
1204         }
1205 
1206         if (test_bit(SCAN_HW_SCANNING, &local->scanning)) {
1207                 /*
1208                  * Make sure that __ieee80211_scan_completed doesn't trigger a
1209                  * scan on another band.
1210                  */
1211                 set_bit(SCAN_HW_CANCELLED, &local->scanning);
1212                 if (local->ops->cancel_hw_scan)
1213                         drv_cancel_hw_scan(local,
1214                                 rcu_dereference_protected(local->scan_sdata,
1215                                                 lockdep_is_held(&local->mtx)));
1216                 goto out;
1217         }
1218 
1219         /*
1220          * If the work is currently running, it must be blocked on
1221          * the mutex, but we'll set scan_sdata = NULL and it'll
1222          * simply exit once it acquires the mutex.
1223          */
1224         cancel_delayed_work(&local->scan_work);
1225         /* and clean up */
1226         memset(&local->scan_info, 0, sizeof(local->scan_info));
1227         __ieee80211_scan_completed(&local->hw, true);
1228 out:
1229         mutex_unlock(&local->mtx);
1230 }
1231 
1232 int __ieee80211_request_sched_scan_start(struct ieee80211_sub_if_data *sdata,
1233                                         struct cfg80211_sched_scan_request *req)
1234 {
1235         struct ieee80211_local *local = sdata->local;
1236         struct ieee80211_scan_ies sched_scan_ies = {};
1237         struct cfg80211_chan_def chandef;
1238         int ret, i, iebufsz, num_bands = 0;
1239         u32 rate_masks[NUM_NL80211_BANDS] = {};
1240         u8 bands_used = 0;
1241         u8 *ie;
1242         u32 flags = 0;
1243 
1244         iebufsz = local->scan_ies_len + req->ie_len;
1245 
1246         lockdep_assert_held(&local->mtx);
1247 
1248         if (!local->ops->sched_scan_start)
1249                 return -ENOTSUPP;
1250 
1251         for (i = 0; i < NUM_NL80211_BANDS; i++) {
1252                 if (local->hw.wiphy->bands[i]) {
1253                         bands_used |= BIT(i);
1254                         rate_masks[i] = (u32) -1;
1255                         num_bands++;
1256                 }
1257         }
1258 
1259         if (req->flags & NL80211_SCAN_FLAG_MIN_PREQ_CONTENT)
1260                 flags |= IEEE80211_PROBE_FLAG_MIN_CONTENT;
1261 
1262         ie = kcalloc(iebufsz, num_bands, GFP_KERNEL);
1263         if (!ie) {
1264                 ret = -ENOMEM;
1265                 goto out;
1266         }
1267 
1268         ieee80211_prepare_scan_chandef(&chandef, req->scan_width);
1269 
1270         ieee80211_build_preq_ies(local, ie, num_bands * iebufsz,
1271                                  &sched_scan_ies, req->ie,
1272                                  req->ie_len, bands_used, rate_masks, &chandef,
1273                                  flags);
1274 
1275         ret = drv_sched_scan_start(local, sdata, req, &sched_scan_ies);
1276         if (ret == 0) {
1277                 rcu_assign_pointer(local->sched_scan_sdata, sdata);
1278                 rcu_assign_pointer(local->sched_scan_req, req);
1279         }
1280 
1281         kfree(ie);
1282 
1283 out:
1284         if (ret) {
1285                 /* Clean in case of failure after HW restart or upon resume. */
1286                 RCU_INIT_POINTER(local->sched_scan_sdata, NULL);
1287                 RCU_INIT_POINTER(local->sched_scan_req, NULL);
1288         }
1289 
1290         return ret;
1291 }
1292 
1293 int ieee80211_request_sched_scan_start(struct ieee80211_sub_if_data *sdata,
1294                                        struct cfg80211_sched_scan_request *req)
1295 {
1296         struct ieee80211_local *local = sdata->local;
1297         int ret;
1298 
1299         mutex_lock(&local->mtx);
1300 
1301         if (rcu_access_pointer(local->sched_scan_sdata)) {
1302                 mutex_unlock(&local->mtx);
1303                 return -EBUSY;
1304         }
1305 
1306         ret = __ieee80211_request_sched_scan_start(sdata, req);
1307 
1308         mutex_unlock(&local->mtx);
1309         return ret;
1310 }
1311 
1312 int ieee80211_request_sched_scan_stop(struct ieee80211_local *local)
1313 {
1314         struct ieee80211_sub_if_data *sched_scan_sdata;
1315         int ret = -ENOENT;
1316 
1317         mutex_lock(&local->mtx);
1318 
1319         if (!local->ops->sched_scan_stop) {
1320                 ret = -ENOTSUPP;
1321                 goto out;
1322         }
1323 
1324         /* We don't want to restart sched scan anymore. */
1325         RCU_INIT_POINTER(local->sched_scan_req, NULL);
1326 
1327         sched_scan_sdata = rcu_dereference_protected(local->sched_scan_sdata,
1328                                                 lockdep_is_held(&local->mtx));
1329         if (sched_scan_sdata) {
1330                 ret = drv_sched_scan_stop(local, sched_scan_sdata);
1331                 if (!ret)
1332                         RCU_INIT_POINTER(local->sched_scan_sdata, NULL);
1333         }
1334 out:
1335         mutex_unlock(&local->mtx);
1336 
1337         return ret;
1338 }
1339 
1340 void ieee80211_sched_scan_results(struct ieee80211_hw *hw)
1341 {
1342         struct ieee80211_local *local = hw_to_local(hw);
1343 
1344         trace_api_sched_scan_results(local);
1345 
1346         cfg80211_sched_scan_results(hw->wiphy, 0);
1347 }
1348 EXPORT_SYMBOL(ieee80211_sched_scan_results);
1349 
1350 void ieee80211_sched_scan_end(struct ieee80211_local *local)
1351 {
1352         mutex_lock(&local->mtx);
1353 
1354         if (!rcu_access_pointer(local->sched_scan_sdata)) {
1355                 mutex_unlock(&local->mtx);
1356                 return;
1357         }
1358 
1359         RCU_INIT_POINTER(local->sched_scan_sdata, NULL);
1360 
1361         /* If sched scan was aborted by the driver. */
1362         RCU_INIT_POINTER(local->sched_scan_req, NULL);
1363 
1364         mutex_unlock(&local->mtx);
1365 
1366         cfg80211_sched_scan_stopped(local->hw.wiphy, 0);
1367 }
1368 
1369 void ieee80211_sched_scan_stopped_work(struct work_struct *work)
1370 {
1371         struct ieee80211_local *local =
1372                 container_of(work, struct ieee80211_local,
1373                              sched_scan_stopped_work);
1374 
1375         ieee80211_sched_scan_end(local);
1376 }
1377 
1378 void ieee80211_sched_scan_stopped(struct ieee80211_hw *hw)
1379 {
1380         struct ieee80211_local *local = hw_to_local(hw);
1381 
1382         trace_api_sched_scan_stopped(local);
1383 
1384         /*
1385          * this shouldn't really happen, so for simplicity
1386          * simply ignore it, and let mac80211 reconfigure
1387          * the sched scan later on.
1388          */
1389         if (local->in_reconfig)
1390                 return;
1391 
1392         schedule_work(&local->sched_scan_stopped_work);
1393 }
1394 EXPORT_SYMBOL(ieee80211_sched_scan_stopped);