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TOMOYO Linux Cross Reference
Linux/net/mac80211/scan.c

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  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) 2018-2024 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 struct inform_bss_update_data {
 59         struct ieee80211_rx_status *rx_status;
 60         bool beacon;
 61 };
 62 
 63 void ieee80211_inform_bss(struct wiphy *wiphy,
 64                           struct cfg80211_bss *cbss,
 65                           const struct cfg80211_bss_ies *ies,
 66                           void *data)
 67 {
 68         struct ieee80211_local *local = wiphy_priv(wiphy);
 69         struct inform_bss_update_data *update_data = data;
 70         struct ieee80211_bss *bss = (void *)cbss->priv;
 71         struct ieee80211_rx_status *rx_status;
 72         struct ieee802_11_elems *elems;
 73         int clen, srlen;
 74 
 75         /* This happens while joining an IBSS */
 76         if (!update_data)
 77                 return;
 78 
 79         elems = ieee802_11_parse_elems(ies->data, ies->len, false, NULL);
 80         if (!elems)
 81                 return;
 82 
 83         rx_status = update_data->rx_status;
 84 
 85         if (update_data->beacon)
 86                 bss->device_ts_beacon = rx_status->device_timestamp;
 87         else
 88                 bss->device_ts_presp = rx_status->device_timestamp;
 89 
 90         if (elems->parse_error) {
 91                 if (update_data->beacon)
 92                         bss->corrupt_data |= IEEE80211_BSS_CORRUPT_BEACON;
 93                 else
 94                         bss->corrupt_data |= IEEE80211_BSS_CORRUPT_PROBE_RESP;
 95         } else {
 96                 if (update_data->beacon)
 97                         bss->corrupt_data &= ~IEEE80211_BSS_CORRUPT_BEACON;
 98                 else
 99                         bss->corrupt_data &= ~IEEE80211_BSS_CORRUPT_PROBE_RESP;
100         }
101 
102         /* save the ERP value so that it is available at association time */
103         if (elems->erp_info && (!elems->parse_error ||
104                                 !(bss->valid_data & IEEE80211_BSS_VALID_ERP))) {
105                 bss->erp_value = elems->erp_info[0];
106                 bss->has_erp_value = true;
107                 if (!elems->parse_error)
108                         bss->valid_data |= IEEE80211_BSS_VALID_ERP;
109         }
110 
111         /* replace old supported rates if we get new values */
112         if (!elems->parse_error ||
113             !(bss->valid_data & IEEE80211_BSS_VALID_RATES)) {
114                 srlen = 0;
115                 if (elems->supp_rates) {
116                         clen = IEEE80211_MAX_SUPP_RATES;
117                         if (clen > elems->supp_rates_len)
118                                 clen = elems->supp_rates_len;
119                         memcpy(bss->supp_rates, elems->supp_rates, clen);
120                         srlen += clen;
121                 }
122                 if (elems->ext_supp_rates) {
123                         clen = IEEE80211_MAX_SUPP_RATES - srlen;
124                         if (clen > elems->ext_supp_rates_len)
125                                 clen = elems->ext_supp_rates_len;
126                         memcpy(bss->supp_rates + srlen, elems->ext_supp_rates,
127                                clen);
128                         srlen += clen;
129                 }
130                 if (srlen) {
131                         bss->supp_rates_len = srlen;
132                         if (!elems->parse_error)
133                                 bss->valid_data |= IEEE80211_BSS_VALID_RATES;
134                 }
135         }
136 
137         if (!elems->parse_error ||
138             !(bss->valid_data & IEEE80211_BSS_VALID_WMM)) {
139                 bss->wmm_used = elems->wmm_param || elems->wmm_info;
140                 bss->uapsd_supported = is_uapsd_supported(elems);
141                 if (!elems->parse_error)
142                         bss->valid_data |= IEEE80211_BSS_VALID_WMM;
143         }
144 
145         if (update_data->beacon) {
146                 struct ieee80211_supported_band *sband =
147                         local->hw.wiphy->bands[rx_status->band];
148                 if (!(rx_status->encoding == RX_ENC_HT) &&
149                     !(rx_status->encoding == RX_ENC_VHT))
150                         bss->beacon_rate =
151                                 &sband->bitrates[rx_status->rate_idx];
152         }
153 
154         if (elems->vht_cap_elem)
155                 bss->vht_cap_info =
156                         le32_to_cpu(elems->vht_cap_elem->vht_cap_info);
157         else
158                 bss->vht_cap_info = 0;
159 
160         kfree(elems);
161 }
162 
163 struct ieee80211_bss *
164 ieee80211_bss_info_update(struct ieee80211_local *local,
165                           struct ieee80211_rx_status *rx_status,
166                           struct ieee80211_mgmt *mgmt, size_t len,
167                           struct ieee80211_channel *channel)
168 {
169         bool beacon = ieee80211_is_beacon(mgmt->frame_control) ||
170                       ieee80211_is_s1g_beacon(mgmt->frame_control);
171         struct cfg80211_bss *cbss;
172         struct inform_bss_update_data update_data = {
173                 .rx_status = rx_status,
174                 .beacon = beacon,
175         };
176         struct cfg80211_inform_bss bss_meta = {
177                 .boottime_ns = rx_status->boottime_ns,
178                 .drv_data = (void *)&update_data,
179         };
180         bool signal_valid;
181         struct ieee80211_sub_if_data *scan_sdata;
182 
183         if (rx_status->flag & RX_FLAG_NO_SIGNAL_VAL)
184                 bss_meta.signal = 0; /* invalid signal indication */
185         else if (ieee80211_hw_check(&local->hw, SIGNAL_DBM))
186                 bss_meta.signal = rx_status->signal * 100;
187         else if (ieee80211_hw_check(&local->hw, SIGNAL_UNSPEC))
188                 bss_meta.signal = (rx_status->signal * 100) / local->hw.max_signal;
189 
190         bss_meta.chan = channel;
191 
192         rcu_read_lock();
193         scan_sdata = rcu_dereference(local->scan_sdata);
194         if (scan_sdata && scan_sdata->vif.type == NL80211_IFTYPE_STATION &&
195             scan_sdata->vif.cfg.assoc &&
196             ieee80211_have_rx_timestamp(rx_status)) {
197                 struct ieee80211_bss_conf *link_conf = NULL;
198 
199                 /* for an MLO connection, set the TSF data only in case we have
200                  * an indication on which of the links the frame was received
201                  */
202                 if (ieee80211_vif_is_mld(&scan_sdata->vif)) {
203                         if (rx_status->link_valid) {
204                                 s8 link_id = rx_status->link_id;
205 
206                                 link_conf =
207                                         rcu_dereference(scan_sdata->vif.link_conf[link_id]);
208                         }
209                 } else {
210                         link_conf = &scan_sdata->vif.bss_conf;
211                 }
212 
213                 if (link_conf) {
214                         bss_meta.parent_tsf =
215                                 ieee80211_calculate_rx_timestamp(local,
216                                                                  rx_status,
217                                                                  len + FCS_LEN,
218                                                                  24);
219 
220                         ether_addr_copy(bss_meta.parent_bssid,
221                                         link_conf->bssid);
222                 }
223         }
224         rcu_read_unlock();
225 
226         cbss = cfg80211_inform_bss_frame_data(local->hw.wiphy, &bss_meta,
227                                               mgmt, len, GFP_ATOMIC);
228         if (!cbss)
229                 return NULL;
230 
231         /* In case the signal is invalid update the status */
232         signal_valid = channel == cbss->channel;
233         if (!signal_valid)
234                 rx_status->flag |= RX_FLAG_NO_SIGNAL_VAL;
235 
236         return (void *)cbss->priv;
237 }
238 
239 static bool ieee80211_scan_accept_presp(struct ieee80211_sub_if_data *sdata,
240                                         struct ieee80211_channel *channel,
241                                         u32 scan_flags, const u8 *da)
242 {
243         if (!sdata)
244                 return false;
245 
246         /* accept broadcast on 6 GHz and for OCE */
247         if (is_broadcast_ether_addr(da) &&
248             (channel->band == NL80211_BAND_6GHZ ||
249              scan_flags & NL80211_SCAN_FLAG_ACCEPT_BCAST_PROBE_RESP))
250                 return true;
251 
252         if (scan_flags & NL80211_SCAN_FLAG_RANDOM_ADDR)
253                 return true;
254         return ether_addr_equal(da, sdata->vif.addr);
255 }
256 
257 void ieee80211_scan_rx(struct ieee80211_local *local, struct sk_buff *skb)
258 {
259         struct ieee80211_rx_status *rx_status = IEEE80211_SKB_RXCB(skb);
260         struct ieee80211_mgmt *mgmt = (void *)skb->data;
261         struct ieee80211_bss *bss;
262         struct ieee80211_channel *channel;
263         size_t min_hdr_len = offsetof(struct ieee80211_mgmt,
264                                       u.probe_resp.variable);
265 
266         if (!ieee80211_is_probe_resp(mgmt->frame_control) &&
267             !ieee80211_is_beacon(mgmt->frame_control) &&
268             !ieee80211_is_s1g_beacon(mgmt->frame_control))
269                 return;
270 
271         if (ieee80211_is_s1g_beacon(mgmt->frame_control)) {
272                 if (ieee80211_is_s1g_short_beacon(mgmt->frame_control))
273                         min_hdr_len = offsetof(struct ieee80211_ext,
274                                                u.s1g_short_beacon.variable);
275                 else
276                         min_hdr_len = offsetof(struct ieee80211_ext,
277                                                u.s1g_beacon);
278         }
279 
280         if (skb->len < min_hdr_len)
281                 return;
282 
283         if (test_and_clear_bit(SCAN_BEACON_WAIT, &local->scanning)) {
284                 /*
285                  * we were passive scanning because of radar/no-IR, but
286                  * the beacon/proberesp rx gives us an opportunity to upgrade
287                  * to active scan
288                  */
289                 set_bit(SCAN_BEACON_DONE, &local->scanning);
290                 wiphy_delayed_work_queue(local->hw.wiphy, &local->scan_work, 0);
291         }
292 
293         channel = ieee80211_get_channel_khz(local->hw.wiphy,
294                                             ieee80211_rx_status_to_khz(rx_status));
295 
296         if (!channel || channel->flags & IEEE80211_CHAN_DISABLED)
297                 return;
298 
299         if (ieee80211_is_probe_resp(mgmt->frame_control)) {
300                 struct ieee80211_sub_if_data *sdata1, *sdata2;
301                 struct cfg80211_scan_request *scan_req;
302                 struct cfg80211_sched_scan_request *sched_scan_req;
303                 u32 scan_req_flags = 0, sched_scan_req_flags = 0;
304 
305                 sdata1 = rcu_dereference(local->scan_sdata);
306                 sdata2 = rcu_dereference(local->sched_scan_sdata);
307 
308                 if (likely(!sdata1 && !sdata2))
309                         return;
310 
311                 scan_req = rcu_dereference(local->scan_req);
312                 sched_scan_req = rcu_dereference(local->sched_scan_req);
313 
314                 if (scan_req)
315                         scan_req_flags = scan_req->flags;
316 
317                 if (sched_scan_req)
318                         sched_scan_req_flags = sched_scan_req->flags;
319 
320                 /* ignore ProbeResp to foreign address or non-bcast (OCE)
321                  * unless scanning with randomised address
322                  */
323                 if (!ieee80211_scan_accept_presp(sdata1, channel,
324                                                  scan_req_flags,
325                                                  mgmt->da) &&
326                     !ieee80211_scan_accept_presp(sdata2, channel,
327                                                  sched_scan_req_flags,
328                                                  mgmt->da))
329                         return;
330         } else {
331                 /* Beacons are expected only with broadcast address */
332                 if (!is_broadcast_ether_addr(mgmt->da))
333                         return;
334         }
335 
336         /* Do not update the BSS table in case of only monitor interfaces */
337         if (local->open_count == local->monitors)
338                 return;
339 
340         bss = ieee80211_bss_info_update(local, rx_status,
341                                         mgmt, skb->len,
342                                         channel);
343         if (bss)
344                 ieee80211_rx_bss_put(local, bss);
345 }
346 
347 static void ieee80211_prepare_scan_chandef(struct cfg80211_chan_def *chandef)
348 {
349         memset(chandef, 0, sizeof(*chandef));
350 
351         chandef->width = NL80211_CHAN_WIDTH_20_NOHT;
352 }
353 
354 /* return false if no more work */
355 static bool ieee80211_prep_hw_scan(struct ieee80211_sub_if_data *sdata)
356 {
357         struct ieee80211_local *local = sdata->local;
358         struct cfg80211_scan_request *req;
359         struct cfg80211_chan_def chandef;
360         u8 bands_used = 0;
361         int i, ielen;
362         u32 *n_chans;
363         u32 flags = 0;
364 
365         req = rcu_dereference_protected(local->scan_req,
366                                         lockdep_is_held(&local->hw.wiphy->mtx));
367 
368         if (test_bit(SCAN_HW_CANCELLED, &local->scanning))
369                 return false;
370 
371         if (ieee80211_hw_check(&local->hw, SINGLE_SCAN_ON_ALL_BANDS)) {
372                 local->hw_scan_req->req.n_channels = req->n_channels;
373 
374                 for (i = 0; i < req->n_channels; i++) {
375                         local->hw_scan_req->req.channels[i] = req->channels[i];
376                         bands_used |= BIT(req->channels[i]->band);
377                 }
378         } else {
379                 do {
380                         if (local->hw_scan_band == NUM_NL80211_BANDS)
381                                 return false;
382 
383                         n_chans = &local->hw_scan_req->req.n_channels;
384                         *n_chans = 0;
385 
386                         for (i = 0; i < req->n_channels; i++) {
387                                 if (req->channels[i]->band !=
388                                     local->hw_scan_band)
389                                         continue;
390                                 local->hw_scan_req->req.channels[(*n_chans)++] =
391                                                         req->channels[i];
392 
393                                 bands_used |= BIT(req->channels[i]->band);
394                         }
395 
396                         local->hw_scan_band++;
397                 } while (!*n_chans);
398         }
399 
400         ieee80211_prepare_scan_chandef(&chandef);
401 
402         if (req->flags & NL80211_SCAN_FLAG_MIN_PREQ_CONTENT)
403                 flags |= IEEE80211_PROBE_FLAG_MIN_CONTENT;
404 
405         ielen = ieee80211_build_preq_ies(sdata,
406                                          (u8 *)local->hw_scan_req->req.ie,
407                                          local->hw_scan_ies_bufsize,
408                                          &local->hw_scan_req->ies,
409                                          req->ie, req->ie_len,
410                                          bands_used, req->rates, &chandef,
411                                          flags);
412         if (ielen < 0)
413                 return false;
414         local->hw_scan_req->req.ie_len = ielen;
415         local->hw_scan_req->req.no_cck = req->no_cck;
416         ether_addr_copy(local->hw_scan_req->req.mac_addr, req->mac_addr);
417         ether_addr_copy(local->hw_scan_req->req.mac_addr_mask,
418                         req->mac_addr_mask);
419         ether_addr_copy(local->hw_scan_req->req.bssid, req->bssid);
420 
421         return true;
422 }
423 
424 static void __ieee80211_scan_completed(struct ieee80211_hw *hw, bool aborted)
425 {
426         struct ieee80211_local *local = hw_to_local(hw);
427         bool hw_scan = test_bit(SCAN_HW_SCANNING, &local->scanning);
428         bool was_scanning = local->scanning;
429         struct cfg80211_scan_request *scan_req;
430         struct ieee80211_sub_if_data *scan_sdata;
431         struct ieee80211_sub_if_data *sdata;
432 
433         lockdep_assert_wiphy(local->hw.wiphy);
434 
435         /*
436          * It's ok to abort a not-yet-running scan (that
437          * we have one at all will be verified by checking
438          * local->scan_req next), but not to complete it
439          * successfully.
440          */
441         if (WARN_ON(!local->scanning && !aborted))
442                 aborted = true;
443 
444         if (WARN_ON(!local->scan_req))
445                 return;
446 
447         scan_sdata = rcu_dereference_protected(local->scan_sdata,
448                                                lockdep_is_held(&local->hw.wiphy->mtx));
449 
450         if (hw_scan && !aborted &&
451             !ieee80211_hw_check(&local->hw, SINGLE_SCAN_ON_ALL_BANDS) &&
452             ieee80211_prep_hw_scan(scan_sdata)) {
453                 int rc;
454 
455                 rc = drv_hw_scan(local,
456                         rcu_dereference_protected(local->scan_sdata,
457                                                   lockdep_is_held(&local->hw.wiphy->mtx)),
458                         local->hw_scan_req);
459 
460                 if (rc == 0)
461                         return;
462 
463                 /* HW scan failed and is going to be reported as aborted,
464                  * so clear old scan info.
465                  */
466                 memset(&local->scan_info, 0, sizeof(local->scan_info));
467                 aborted = true;
468         }
469 
470         kfree(local->hw_scan_req);
471         local->hw_scan_req = NULL;
472 
473         scan_req = rcu_dereference_protected(local->scan_req,
474                                              lockdep_is_held(&local->hw.wiphy->mtx));
475 
476         RCU_INIT_POINTER(local->scan_req, NULL);
477         RCU_INIT_POINTER(local->scan_sdata, NULL);
478 
479         local->scanning = 0;
480         local->scan_chandef.chan = NULL;
481 
482         synchronize_rcu();
483 
484         if (scan_req != local->int_scan_req) {
485                 local->scan_info.aborted = aborted;
486                 cfg80211_scan_done(scan_req, &local->scan_info);
487         }
488 
489         /* Set power back to normal operating levels. */
490         ieee80211_hw_conf_chan(local);
491 
492         if (!hw_scan && was_scanning) {
493                 ieee80211_configure_filter(local);
494                 drv_sw_scan_complete(local, scan_sdata);
495                 ieee80211_offchannel_return(local);
496         }
497 
498         ieee80211_recalc_idle(local);
499 
500         ieee80211_mlme_notify_scan_completed(local);
501         ieee80211_ibss_notify_scan_completed(local);
502 
503         /* Requeue all the work that might have been ignored while
504          * the scan was in progress; if there was none this will
505          * just be a no-op for the particular interface.
506          */
507         list_for_each_entry(sdata, &local->interfaces, list) {
508                 if (ieee80211_sdata_running(sdata))
509                         wiphy_work_queue(sdata->local->hw.wiphy, &sdata->work);
510         }
511 
512         if (was_scanning)
513                 ieee80211_start_next_roc(local);
514 }
515 
516 void ieee80211_scan_completed(struct ieee80211_hw *hw,
517                               struct cfg80211_scan_info *info)
518 {
519         struct ieee80211_local *local = hw_to_local(hw);
520 
521         trace_api_scan_completed(local, info->aborted);
522 
523         set_bit(SCAN_COMPLETED, &local->scanning);
524         if (info->aborted)
525                 set_bit(SCAN_ABORTED, &local->scanning);
526 
527         memcpy(&local->scan_info, info, sizeof(*info));
528 
529         wiphy_delayed_work_queue(local->hw.wiphy, &local->scan_work, 0);
530 }
531 EXPORT_SYMBOL(ieee80211_scan_completed);
532 
533 static int ieee80211_start_sw_scan(struct ieee80211_local *local,
534                                    struct ieee80211_sub_if_data *sdata)
535 {
536         /* Software scan is not supported in multi-channel cases */
537         if (!local->emulate_chanctx)
538                 return -EOPNOTSUPP;
539 
540         /*
541          * Hardware/driver doesn't support hw_scan, so use software
542          * scanning instead. First send a nullfunc frame with power save
543          * bit on so that AP will buffer the frames for us while we are not
544          * listening, then send probe requests to each channel and wait for
545          * the responses. After all channels are scanned, tune back to the
546          * original channel and send a nullfunc frame with power save bit
547          * off to trigger the AP to send us all the buffered frames.
548          *
549          * Note that while local->sw_scanning is true everything else but
550          * nullfunc frames and probe requests will be dropped in
551          * ieee80211_tx_h_check_assoc().
552          */
553         drv_sw_scan_start(local, sdata, local->scan_addr);
554 
555         local->leave_oper_channel_time = jiffies;
556         local->next_scan_state = SCAN_DECISION;
557         local->scan_channel_idx = 0;
558 
559         ieee80211_offchannel_stop_vifs(local);
560 
561         /* ensure nullfunc is transmitted before leaving operating channel */
562         ieee80211_flush_queues(local, NULL, false);
563 
564         ieee80211_configure_filter(local);
565 
566         /* We need to set power level at maximum rate for scanning. */
567         ieee80211_hw_conf_chan(local);
568 
569         wiphy_delayed_work_queue(local->hw.wiphy, &local->scan_work, 0);
570 
571         return 0;
572 }
573 
574 static bool __ieee80211_can_leave_ch(struct ieee80211_sub_if_data *sdata)
575 {
576         struct ieee80211_local *local = sdata->local;
577         struct ieee80211_sub_if_data *sdata_iter;
578 
579         lockdep_assert_wiphy(local->hw.wiphy);
580 
581         if (!ieee80211_is_radar_required(local))
582                 return true;
583 
584         if (!regulatory_pre_cac_allowed(local->hw.wiphy))
585                 return false;
586 
587         list_for_each_entry(sdata_iter, &local->interfaces, list) {
588                 if (sdata_iter->wdev.cac_started)
589                         return false;
590         }
591 
592         return true;
593 }
594 
595 static bool ieee80211_can_scan(struct ieee80211_local *local,
596                                struct ieee80211_sub_if_data *sdata)
597 {
598         if (!__ieee80211_can_leave_ch(sdata))
599                 return false;
600 
601         if (!list_empty(&local->roc_list))
602                 return false;
603 
604         if (sdata->vif.type == NL80211_IFTYPE_STATION &&
605             sdata->u.mgd.flags & IEEE80211_STA_CONNECTION_POLL)
606                 return false;
607 
608         return true;
609 }
610 
611 void ieee80211_run_deferred_scan(struct ieee80211_local *local)
612 {
613         lockdep_assert_wiphy(local->hw.wiphy);
614 
615         if (!local->scan_req || local->scanning)
616                 return;
617 
618         if (!ieee80211_can_scan(local,
619                                 rcu_dereference_protected(
620                                         local->scan_sdata,
621                                         lockdep_is_held(&local->hw.wiphy->mtx))))
622                 return;
623 
624         wiphy_delayed_work_queue(local->hw.wiphy, &local->scan_work,
625                                  round_jiffies_relative(0));
626 }
627 
628 static void ieee80211_send_scan_probe_req(struct ieee80211_sub_if_data *sdata,
629                                           const u8 *src, const u8 *dst,
630                                           const u8 *ssid, size_t ssid_len,
631                                           const u8 *ie, size_t ie_len,
632                                           u32 ratemask, u32 flags, u32 tx_flags,
633                                           struct ieee80211_channel *channel)
634 {
635         struct sk_buff *skb;
636 
637         skb = ieee80211_build_probe_req(sdata, src, dst, ratemask, channel,
638                                         ssid, ssid_len,
639                                         ie, ie_len, flags);
640 
641         if (skb) {
642                 if (flags & IEEE80211_PROBE_FLAG_RANDOM_SN) {
643                         struct ieee80211_hdr *hdr = (void *)skb->data;
644                         struct ieee80211_tx_info *info = IEEE80211_SKB_CB(skb);
645                         u16 sn = get_random_u16();
646 
647                         info->control.flags |= IEEE80211_TX_CTRL_NO_SEQNO;
648                         hdr->seq_ctrl =
649                                 cpu_to_le16(IEEE80211_SN_TO_SEQ(sn));
650                 }
651                 IEEE80211_SKB_CB(skb)->flags |= tx_flags;
652                 IEEE80211_SKB_CB(skb)->control.flags |= IEEE80211_TX_CTRL_DONT_USE_RATE_MASK;
653                 ieee80211_tx_skb_tid_band(sdata, skb, 7, channel->band);
654         }
655 }
656 
657 static void ieee80211_scan_state_send_probe(struct ieee80211_local *local,
658                                             unsigned long *next_delay)
659 {
660         int i;
661         struct ieee80211_sub_if_data *sdata;
662         struct cfg80211_scan_request *scan_req;
663         enum nl80211_band band = local->hw.conf.chandef.chan->band;
664         u32 flags = 0, tx_flags;
665 
666         scan_req = rcu_dereference_protected(local->scan_req,
667                                              lockdep_is_held(&local->hw.wiphy->mtx));
668 
669         tx_flags = IEEE80211_TX_INTFL_OFFCHAN_TX_OK;
670         if (scan_req->no_cck)
671                 tx_flags |= IEEE80211_TX_CTL_NO_CCK_RATE;
672         if (scan_req->flags & NL80211_SCAN_FLAG_MIN_PREQ_CONTENT)
673                 flags |= IEEE80211_PROBE_FLAG_MIN_CONTENT;
674         if (scan_req->flags & NL80211_SCAN_FLAG_RANDOM_SN)
675                 flags |= IEEE80211_PROBE_FLAG_RANDOM_SN;
676 
677         sdata = rcu_dereference_protected(local->scan_sdata,
678                                           lockdep_is_held(&local->hw.wiphy->mtx));
679 
680         for (i = 0; i < scan_req->n_ssids; i++)
681                 ieee80211_send_scan_probe_req(
682                         sdata, local->scan_addr, scan_req->bssid,
683                         scan_req->ssids[i].ssid, scan_req->ssids[i].ssid_len,
684                         scan_req->ie, scan_req->ie_len,
685                         scan_req->rates[band], flags,
686                         tx_flags, local->hw.conf.chandef.chan);
687 
688         /*
689          * After sending probe requests, wait for probe responses
690          * on the channel.
691          */
692         *next_delay = msecs_to_jiffies(scan_req->duration) >
693                       IEEE80211_PROBE_DELAY + IEEE80211_CHANNEL_TIME ?
694                       msecs_to_jiffies(scan_req->duration) - IEEE80211_PROBE_DELAY :
695                       IEEE80211_CHANNEL_TIME;
696         local->next_scan_state = SCAN_DECISION;
697 }
698 
699 static int __ieee80211_start_scan(struct ieee80211_sub_if_data *sdata,
700                                   struct cfg80211_scan_request *req)
701 {
702         struct ieee80211_local *local = sdata->local;
703         bool hw_scan = local->ops->hw_scan;
704         int rc;
705 
706         lockdep_assert_wiphy(local->hw.wiphy);
707 
708         if (local->scan_req)
709                 return -EBUSY;
710 
711         /* For an MLO connection, if a link ID was specified, validate that it
712          * is indeed active.
713          */
714         if (ieee80211_vif_is_mld(&sdata->vif) && req->tsf_report_link_id >= 0 &&
715             !(sdata->vif.active_links & BIT(req->tsf_report_link_id)))
716                 return -EINVAL;
717 
718         if (!__ieee80211_can_leave_ch(sdata))
719                 return -EBUSY;
720 
721         if (!ieee80211_can_scan(local, sdata)) {
722                 /* wait for the work to finish/time out */
723                 rcu_assign_pointer(local->scan_req, req);
724                 rcu_assign_pointer(local->scan_sdata, sdata);
725                 return 0;
726         }
727 
728  again:
729         if (hw_scan) {
730                 u8 *ies;
731 
732                 local->hw_scan_ies_bufsize = local->scan_ies_len + req->ie_len;
733 
734                 if (ieee80211_hw_check(&local->hw, SINGLE_SCAN_ON_ALL_BANDS)) {
735                         int i, n_bands = 0;
736                         u8 bands_counted = 0;
737 
738                         for (i = 0; i < req->n_channels; i++) {
739                                 if (bands_counted & BIT(req->channels[i]->band))
740                                         continue;
741                                 bands_counted |= BIT(req->channels[i]->band);
742                                 n_bands++;
743                         }
744 
745                         local->hw_scan_ies_bufsize *= n_bands;
746                 }
747 
748                 local->hw_scan_req = kmalloc(struct_size(local->hw_scan_req,
749                                                          req.channels,
750                                                          req->n_channels) +
751                                              local->hw_scan_ies_bufsize,
752                                              GFP_KERNEL);
753                 if (!local->hw_scan_req)
754                         return -ENOMEM;
755 
756                 local->hw_scan_req->req.ssids = req->ssids;
757                 local->hw_scan_req->req.n_ssids = req->n_ssids;
758                 /* None of the channels are actually set
759                  * up but let UBSAN know the boundaries.
760                  */
761                 local->hw_scan_req->req.n_channels = req->n_channels;
762 
763                 ies = (u8 *)local->hw_scan_req +
764                         sizeof(*local->hw_scan_req) +
765                         req->n_channels * sizeof(req->channels[0]);
766                 local->hw_scan_req->req.ie = ies;
767                 local->hw_scan_req->req.flags = req->flags;
768                 eth_broadcast_addr(local->hw_scan_req->req.bssid);
769                 local->hw_scan_req->req.duration = req->duration;
770                 local->hw_scan_req->req.duration_mandatory =
771                         req->duration_mandatory;
772                 local->hw_scan_req->req.tsf_report_link_id =
773                         req->tsf_report_link_id;
774 
775                 local->hw_scan_band = 0;
776                 local->hw_scan_req->req.n_6ghz_params = req->n_6ghz_params;
777                 local->hw_scan_req->req.scan_6ghz_params =
778                         req->scan_6ghz_params;
779                 local->hw_scan_req->req.scan_6ghz = req->scan_6ghz;
780 
781                 /*
782                  * After allocating local->hw_scan_req, we must
783                  * go through until ieee80211_prep_hw_scan(), so
784                  * anything that might be changed here and leave
785                  * this function early must not go after this
786                  * allocation.
787                  */
788         }
789 
790         rcu_assign_pointer(local->scan_req, req);
791         rcu_assign_pointer(local->scan_sdata, sdata);
792 
793         if (req->flags & NL80211_SCAN_FLAG_RANDOM_ADDR)
794                 get_random_mask_addr(local->scan_addr,
795                                      req->mac_addr,
796                                      req->mac_addr_mask);
797         else
798                 memcpy(local->scan_addr, sdata->vif.addr, ETH_ALEN);
799 
800         if (hw_scan) {
801                 __set_bit(SCAN_HW_SCANNING, &local->scanning);
802         } else if ((req->n_channels == 1) &&
803                    (req->channels[0] == local->hw.conf.chandef.chan)) {
804                 /*
805                  * If we are scanning only on the operating channel
806                  * then we do not need to stop normal activities
807                  */
808                 unsigned long next_delay;
809 
810                 __set_bit(SCAN_ONCHANNEL_SCANNING, &local->scanning);
811 
812                 ieee80211_recalc_idle(local);
813 
814                 /* Notify driver scan is starting, keep order of operations
815                  * same as normal software scan, in case that matters. */
816                 drv_sw_scan_start(local, sdata, local->scan_addr);
817 
818                 ieee80211_configure_filter(local); /* accept probe-responses */
819 
820                 /* We need to ensure power level is at max for scanning. */
821                 ieee80211_hw_conf_chan(local);
822 
823                 if ((req->channels[0]->flags & (IEEE80211_CHAN_NO_IR |
824                                                 IEEE80211_CHAN_RADAR)) ||
825                     !req->n_ssids) {
826                         next_delay = IEEE80211_PASSIVE_CHANNEL_TIME;
827                         if (req->n_ssids)
828                                 set_bit(SCAN_BEACON_WAIT, &local->scanning);
829                 } else {
830                         ieee80211_scan_state_send_probe(local, &next_delay);
831                         next_delay = IEEE80211_CHANNEL_TIME;
832                 }
833 
834                 /* Now, just wait a bit and we are all done! */
835                 wiphy_delayed_work_queue(local->hw.wiphy, &local->scan_work,
836                                          next_delay);
837                 return 0;
838         } else {
839                 /* Do normal software scan */
840                 __set_bit(SCAN_SW_SCANNING, &local->scanning);
841         }
842 
843         ieee80211_recalc_idle(local);
844 
845         if (hw_scan) {
846                 WARN_ON(!ieee80211_prep_hw_scan(sdata));
847                 rc = drv_hw_scan(local, sdata, local->hw_scan_req);
848         } else {
849                 rc = ieee80211_start_sw_scan(local, sdata);
850         }
851 
852         if (rc) {
853                 kfree(local->hw_scan_req);
854                 local->hw_scan_req = NULL;
855                 local->scanning = 0;
856 
857                 ieee80211_recalc_idle(local);
858 
859                 local->scan_req = NULL;
860                 RCU_INIT_POINTER(local->scan_sdata, NULL);
861         }
862 
863         if (hw_scan && rc == 1) {
864                 /*
865                  * we can't fall back to software for P2P-GO
866                  * as it must update NoA etc.
867                  */
868                 if (ieee80211_vif_type_p2p(&sdata->vif) ==
869                                 NL80211_IFTYPE_P2P_GO)
870                         return -EOPNOTSUPP;
871                 hw_scan = false;
872                 goto again;
873         }
874 
875         return rc;
876 }
877 
878 static unsigned long
879 ieee80211_scan_get_channel_time(struct ieee80211_channel *chan)
880 {
881         /*
882          * TODO: channel switching also consumes quite some time,
883          * add that delay as well to get a better estimation
884          */
885         if (chan->flags & (IEEE80211_CHAN_NO_IR | IEEE80211_CHAN_RADAR))
886                 return IEEE80211_PASSIVE_CHANNEL_TIME;
887         return IEEE80211_PROBE_DELAY + IEEE80211_CHANNEL_TIME;
888 }
889 
890 static void ieee80211_scan_state_decision(struct ieee80211_local *local,
891                                           unsigned long *next_delay)
892 {
893         bool associated = false;
894         bool tx_empty = true;
895         bool bad_latency;
896         struct ieee80211_sub_if_data *sdata;
897         struct ieee80211_channel *next_chan;
898         enum mac80211_scan_state next_scan_state;
899         struct cfg80211_scan_request *scan_req;
900 
901         lockdep_assert_wiphy(local->hw.wiphy);
902 
903         /*
904          * check if at least one STA interface is associated,
905          * check if at least one STA interface has pending tx frames
906          * and grab the lowest used beacon interval
907          */
908         list_for_each_entry(sdata, &local->interfaces, list) {
909                 if (!ieee80211_sdata_running(sdata))
910                         continue;
911 
912                 if (sdata->vif.type == NL80211_IFTYPE_STATION) {
913                         if (sdata->u.mgd.associated) {
914                                 associated = true;
915 
916                                 if (!qdisc_all_tx_empty(sdata->dev)) {
917                                         tx_empty = false;
918                                         break;
919                                 }
920                         }
921                 }
922         }
923 
924         scan_req = rcu_dereference_protected(local->scan_req,
925                                              lockdep_is_held(&local->hw.wiphy->mtx));
926 
927         next_chan = scan_req->channels[local->scan_channel_idx];
928 
929         /*
930          * we're currently scanning a different channel, let's
931          * see if we can scan another channel without interfering
932          * with the current traffic situation.
933          *
934          * Keep good latency, do not stay off-channel more than 125 ms.
935          */
936 
937         bad_latency = time_after(jiffies +
938                                  ieee80211_scan_get_channel_time(next_chan),
939                                  local->leave_oper_channel_time + HZ / 8);
940 
941         if (associated && !tx_empty) {
942                 if (scan_req->flags & NL80211_SCAN_FLAG_LOW_PRIORITY)
943                         next_scan_state = SCAN_ABORT;
944                 else
945                         next_scan_state = SCAN_SUSPEND;
946         } else if (associated && bad_latency) {
947                 next_scan_state = SCAN_SUSPEND;
948         } else {
949                 next_scan_state = SCAN_SET_CHANNEL;
950         }
951 
952         local->next_scan_state = next_scan_state;
953 
954         *next_delay = 0;
955 }
956 
957 static void ieee80211_scan_state_set_channel(struct ieee80211_local *local,
958                                              unsigned long *next_delay)
959 {
960         int skip;
961         struct ieee80211_channel *chan;
962         struct cfg80211_scan_request *scan_req;
963 
964         scan_req = rcu_dereference_protected(local->scan_req,
965                                              lockdep_is_held(&local->hw.wiphy->mtx));
966 
967         skip = 0;
968         chan = scan_req->channels[local->scan_channel_idx];
969 
970         local->scan_chandef.chan = chan;
971         local->scan_chandef.center_freq1 = chan->center_freq;
972         local->scan_chandef.freq1_offset = chan->freq_offset;
973         local->scan_chandef.center_freq2 = 0;
974 
975         /* For scanning on the S1G band, detect the channel width according to
976          * the channel being scanned.
977          */
978         if (chan->band == NL80211_BAND_S1GHZ) {
979                 local->scan_chandef.width = ieee80211_s1g_channel_width(chan);
980                 goto set_channel;
981         }
982 
983         /* If scanning on oper channel, use whatever channel-type
984          * is currently in use.
985          */
986         if (chan == local->hw.conf.chandef.chan)
987                 local->scan_chandef = local->hw.conf.chandef;
988         else
989                 local->scan_chandef.width = NL80211_CHAN_WIDTH_20_NOHT;
990 
991 set_channel:
992         if (ieee80211_hw_conf_chan(local))
993                 skip = 1;
994 
995         /* advance state machine to next channel/band */
996         local->scan_channel_idx++;
997 
998         if (skip) {
999                 /* if we skip this channel return to the decision state */
1000                 local->next_scan_state = SCAN_DECISION;
1001                 return;
1002         }
1003 
1004         /*
1005          * Probe delay is used to update the NAV, cf. 11.1.3.2.2
1006          * (which unfortunately doesn't say _why_ step a) is done,
1007          * but it waits for the probe delay or until a frame is
1008          * received - and the received frame would update the NAV).
1009          * For now, we do not support waiting until a frame is
1010          * received.
1011          *
1012          * In any case, it is not necessary for a passive scan.
1013          */
1014         if ((chan->flags & (IEEE80211_CHAN_NO_IR | IEEE80211_CHAN_RADAR)) ||
1015             !scan_req->n_ssids) {
1016                 *next_delay = msecs_to_jiffies(scan_req->duration) >
1017                               IEEE80211_PASSIVE_CHANNEL_TIME ?
1018                               msecs_to_jiffies(scan_req->duration) :
1019                               IEEE80211_PASSIVE_CHANNEL_TIME;
1020                 local->next_scan_state = SCAN_DECISION;
1021                 if (scan_req->n_ssids)
1022                         set_bit(SCAN_BEACON_WAIT, &local->scanning);
1023                 return;
1024         }
1025 
1026         /* active scan, send probes */
1027         *next_delay = IEEE80211_PROBE_DELAY;
1028         local->next_scan_state = SCAN_SEND_PROBE;
1029 }
1030 
1031 static void ieee80211_scan_state_suspend(struct ieee80211_local *local,
1032                                          unsigned long *next_delay)
1033 {
1034         /* switch back to the operating channel */
1035         local->scan_chandef.chan = NULL;
1036         ieee80211_hw_conf_chan(local);
1037 
1038         /* disable PS */
1039         ieee80211_offchannel_return(local);
1040 
1041         *next_delay = HZ / 5;
1042         /* afterwards, resume scan & go to next channel */
1043         local->next_scan_state = SCAN_RESUME;
1044 }
1045 
1046 static void ieee80211_scan_state_resume(struct ieee80211_local *local,
1047                                         unsigned long *next_delay)
1048 {
1049         ieee80211_offchannel_stop_vifs(local);
1050 
1051         if (local->ops->flush) {
1052                 ieee80211_flush_queues(local, NULL, false);
1053                 *next_delay = 0;
1054         } else
1055                 *next_delay = HZ / 10;
1056 
1057         /* remember when we left the operating channel */
1058         local->leave_oper_channel_time = jiffies;
1059 
1060         /* advance to the next channel to be scanned */
1061         local->next_scan_state = SCAN_SET_CHANNEL;
1062 }
1063 
1064 void ieee80211_scan_work(struct wiphy *wiphy, struct wiphy_work *work)
1065 {
1066         struct ieee80211_local *local =
1067                 container_of(work, struct ieee80211_local, scan_work.work);
1068         struct ieee80211_sub_if_data *sdata;
1069         struct cfg80211_scan_request *scan_req;
1070         unsigned long next_delay = 0;
1071         bool aborted;
1072 
1073         lockdep_assert_wiphy(local->hw.wiphy);
1074 
1075         if (!ieee80211_can_run_worker(local)) {
1076                 aborted = true;
1077                 goto out_complete;
1078         }
1079 
1080         sdata = rcu_dereference_protected(local->scan_sdata,
1081                                           lockdep_is_held(&local->hw.wiphy->mtx));
1082         scan_req = rcu_dereference_protected(local->scan_req,
1083                                              lockdep_is_held(&local->hw.wiphy->mtx));
1084 
1085         /* When scanning on-channel, the first-callback means completed. */
1086         if (test_bit(SCAN_ONCHANNEL_SCANNING, &local->scanning)) {
1087                 aborted = test_and_clear_bit(SCAN_ABORTED, &local->scanning);
1088                 goto out_complete;
1089         }
1090 
1091         if (test_and_clear_bit(SCAN_COMPLETED, &local->scanning)) {
1092                 aborted = test_and_clear_bit(SCAN_ABORTED, &local->scanning);
1093                 goto out_complete;
1094         }
1095 
1096         if (!sdata || !scan_req)
1097                 return;
1098 
1099         if (!local->scanning) {
1100                 int rc;
1101 
1102                 RCU_INIT_POINTER(local->scan_req, NULL);
1103                 RCU_INIT_POINTER(local->scan_sdata, NULL);
1104 
1105                 rc = __ieee80211_start_scan(sdata, scan_req);
1106                 if (!rc)
1107                         return;
1108                 /* need to complete scan in cfg80211 */
1109                 rcu_assign_pointer(local->scan_req, scan_req);
1110                 aborted = true;
1111                 goto out_complete;
1112         }
1113 
1114         clear_bit(SCAN_BEACON_WAIT, &local->scanning);
1115 
1116         /*
1117          * as long as no delay is required advance immediately
1118          * without scheduling a new work
1119          */
1120         do {
1121                 if (!ieee80211_sdata_running(sdata)) {
1122                         aborted = true;
1123                         goto out_complete;
1124                 }
1125 
1126                 if (test_and_clear_bit(SCAN_BEACON_DONE, &local->scanning) &&
1127                     local->next_scan_state == SCAN_DECISION)
1128                         local->next_scan_state = SCAN_SEND_PROBE;
1129 
1130                 switch (local->next_scan_state) {
1131                 case SCAN_DECISION:
1132                         /* if no more bands/channels left, complete scan */
1133                         if (local->scan_channel_idx >= scan_req->n_channels) {
1134                                 aborted = false;
1135                                 goto out_complete;
1136                         }
1137                         ieee80211_scan_state_decision(local, &next_delay);
1138                         break;
1139                 case SCAN_SET_CHANNEL:
1140                         ieee80211_scan_state_set_channel(local, &next_delay);
1141                         break;
1142                 case SCAN_SEND_PROBE:
1143                         ieee80211_scan_state_send_probe(local, &next_delay);
1144                         break;
1145                 case SCAN_SUSPEND:
1146                         ieee80211_scan_state_suspend(local, &next_delay);
1147                         break;
1148                 case SCAN_RESUME:
1149                         ieee80211_scan_state_resume(local, &next_delay);
1150                         break;
1151                 case SCAN_ABORT:
1152                         aborted = true;
1153                         goto out_complete;
1154                 }
1155         } while (next_delay == 0);
1156 
1157         wiphy_delayed_work_queue(local->hw.wiphy, &local->scan_work,
1158                                  next_delay);
1159         return;
1160 
1161 out_complete:
1162         __ieee80211_scan_completed(&local->hw, aborted);
1163 }
1164 
1165 int ieee80211_request_scan(struct ieee80211_sub_if_data *sdata,
1166                            struct cfg80211_scan_request *req)
1167 {
1168         lockdep_assert_wiphy(sdata->local->hw.wiphy);
1169 
1170         return __ieee80211_start_scan(sdata, req);
1171 }
1172 
1173 int ieee80211_request_ibss_scan(struct ieee80211_sub_if_data *sdata,
1174                                 const u8 *ssid, u8 ssid_len,
1175                                 struct ieee80211_channel **channels,
1176                                 unsigned int n_channels)
1177 {
1178         struct ieee80211_local *local = sdata->local;
1179         int ret = -EBUSY, i, n_ch = 0;
1180         enum nl80211_band band;
1181 
1182         lockdep_assert_wiphy(local->hw.wiphy);
1183 
1184         /* busy scanning */
1185         if (local->scan_req)
1186                 goto unlock;
1187 
1188         /* fill internal scan request */
1189         if (!channels) {
1190                 int max_n;
1191 
1192                 for (band = 0; band < NUM_NL80211_BANDS; band++) {
1193                         if (!local->hw.wiphy->bands[band] ||
1194                             band == NL80211_BAND_6GHZ)
1195                                 continue;
1196 
1197                         max_n = local->hw.wiphy->bands[band]->n_channels;
1198                         for (i = 0; i < max_n; i++) {
1199                                 struct ieee80211_channel *tmp_ch =
1200                                     &local->hw.wiphy->bands[band]->channels[i];
1201 
1202                                 if (tmp_ch->flags & (IEEE80211_CHAN_NO_IR |
1203                                                      IEEE80211_CHAN_DISABLED))
1204                                         continue;
1205 
1206                                 local->int_scan_req->channels[n_ch] = tmp_ch;
1207                                 n_ch++;
1208                         }
1209                 }
1210 
1211                 if (WARN_ON_ONCE(n_ch == 0))
1212                         goto unlock;
1213 
1214                 local->int_scan_req->n_channels = n_ch;
1215         } else {
1216                 for (i = 0; i < n_channels; i++) {
1217                         if (channels[i]->flags & (IEEE80211_CHAN_NO_IR |
1218                                                   IEEE80211_CHAN_DISABLED))
1219                                 continue;
1220 
1221                         local->int_scan_req->channels[n_ch] = channels[i];
1222                         n_ch++;
1223                 }
1224 
1225                 if (WARN_ON_ONCE(n_ch == 0))
1226                         goto unlock;
1227 
1228                 local->int_scan_req->n_channels = n_ch;
1229         }
1230 
1231         local->int_scan_req->ssids = &local->scan_ssid;
1232         local->int_scan_req->n_ssids = 1;
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         return ret;
1239 }
1240 
1241 void ieee80211_scan_cancel(struct ieee80211_local *local)
1242 {
1243         /* ensure a new scan cannot be queued */
1244         lockdep_assert_wiphy(local->hw.wiphy);
1245 
1246         /*
1247          * We are canceling software scan, or deferred scan that was not
1248          * yet really started (see __ieee80211_start_scan ).
1249          *
1250          * Regarding hardware scan:
1251          * - we can not call  __ieee80211_scan_completed() as when
1252          *   SCAN_HW_SCANNING bit is set this function change
1253          *   local->hw_scan_req to operate on 5G band, what race with
1254          *   driver which can use local->hw_scan_req
1255          *
1256          * - we can not cancel scan_work since driver can schedule it
1257          *   by ieee80211_scan_completed(..., true) to finish scan
1258          *
1259          * Hence we only call the cancel_hw_scan() callback, but the low-level
1260          * driver is still responsible for calling ieee80211_scan_completed()
1261          * after the scan was completed/aborted.
1262          */
1263 
1264         if (!local->scan_req)
1265                 return;
1266 
1267         /*
1268          * We have a scan running and the driver already reported completion,
1269          * but the worker hasn't run yet or is stuck on the mutex - mark it as
1270          * cancelled.
1271          */
1272         if (test_bit(SCAN_HW_SCANNING, &local->scanning) &&
1273             test_bit(SCAN_COMPLETED, &local->scanning)) {
1274                 set_bit(SCAN_HW_CANCELLED, &local->scanning);
1275                 return;
1276         }
1277 
1278         if (test_bit(SCAN_HW_SCANNING, &local->scanning)) {
1279                 /*
1280                  * Make sure that __ieee80211_scan_completed doesn't trigger a
1281                  * scan on another band.
1282                  */
1283                 set_bit(SCAN_HW_CANCELLED, &local->scanning);
1284                 if (local->ops->cancel_hw_scan)
1285                         drv_cancel_hw_scan(local,
1286                                 rcu_dereference_protected(local->scan_sdata,
1287                                                 lockdep_is_held(&local->hw.wiphy->mtx)));
1288                 return;
1289         }
1290 
1291         wiphy_delayed_work_cancel(local->hw.wiphy, &local->scan_work);
1292         /* and clean up */
1293         memset(&local->scan_info, 0, sizeof(local->scan_info));
1294         __ieee80211_scan_completed(&local->hw, true);
1295 }
1296 
1297 int __ieee80211_request_sched_scan_start(struct ieee80211_sub_if_data *sdata,
1298                                         struct cfg80211_sched_scan_request *req)
1299 {
1300         struct ieee80211_local *local = sdata->local;
1301         struct ieee80211_scan_ies sched_scan_ies = {};
1302         struct cfg80211_chan_def chandef;
1303         int ret, i, iebufsz, num_bands = 0;
1304         u32 rate_masks[NUM_NL80211_BANDS] = {};
1305         u8 bands_used = 0;
1306         u8 *ie;
1307         u32 flags = 0;
1308 
1309         lockdep_assert_wiphy(local->hw.wiphy);
1310 
1311         iebufsz = local->scan_ies_len + req->ie_len;
1312 
1313         if (!local->ops->sched_scan_start)
1314                 return -EOPNOTSUPP;
1315 
1316         for (i = 0; i < NUM_NL80211_BANDS; i++) {
1317                 if (local->hw.wiphy->bands[i]) {
1318                         bands_used |= BIT(i);
1319                         rate_masks[i] = (u32) -1;
1320                         num_bands++;
1321                 }
1322         }
1323 
1324         if (req->flags & NL80211_SCAN_FLAG_MIN_PREQ_CONTENT)
1325                 flags |= IEEE80211_PROBE_FLAG_MIN_CONTENT;
1326 
1327         ie = kcalloc(iebufsz, num_bands, GFP_KERNEL);
1328         if (!ie) {
1329                 ret = -ENOMEM;
1330                 goto out;
1331         }
1332 
1333         ieee80211_prepare_scan_chandef(&chandef);
1334 
1335         ret = ieee80211_build_preq_ies(sdata, ie, num_bands * iebufsz,
1336                                        &sched_scan_ies, req->ie,
1337                                        req->ie_len, bands_used, rate_masks,
1338                                        &chandef, flags);
1339         if (ret < 0)
1340                 goto error;
1341 
1342         ret = drv_sched_scan_start(local, sdata, req, &sched_scan_ies);
1343         if (ret == 0) {
1344                 rcu_assign_pointer(local->sched_scan_sdata, sdata);
1345                 rcu_assign_pointer(local->sched_scan_req, req);
1346         }
1347 
1348 error:
1349         kfree(ie);
1350 out:
1351         if (ret) {
1352                 /* Clean in case of failure after HW restart or upon resume. */
1353                 RCU_INIT_POINTER(local->sched_scan_sdata, NULL);
1354                 RCU_INIT_POINTER(local->sched_scan_req, NULL);
1355         }
1356 
1357         return ret;
1358 }
1359 
1360 int ieee80211_request_sched_scan_start(struct ieee80211_sub_if_data *sdata,
1361                                        struct cfg80211_sched_scan_request *req)
1362 {
1363         struct ieee80211_local *local = sdata->local;
1364 
1365         lockdep_assert_wiphy(local->hw.wiphy);
1366 
1367         if (rcu_access_pointer(local->sched_scan_sdata))
1368                 return -EBUSY;
1369 
1370         return __ieee80211_request_sched_scan_start(sdata, req);
1371 }
1372 
1373 int ieee80211_request_sched_scan_stop(struct ieee80211_local *local)
1374 {
1375         struct ieee80211_sub_if_data *sched_scan_sdata;
1376         int ret = -ENOENT;
1377 
1378         lockdep_assert_wiphy(local->hw.wiphy);
1379 
1380         if (!local->ops->sched_scan_stop)
1381                 return -EOPNOTSUPP;
1382 
1383         /* We don't want to restart sched scan anymore. */
1384         RCU_INIT_POINTER(local->sched_scan_req, NULL);
1385 
1386         sched_scan_sdata = rcu_dereference_protected(local->sched_scan_sdata,
1387                                                 lockdep_is_held(&local->hw.wiphy->mtx));
1388         if (sched_scan_sdata) {
1389                 ret = drv_sched_scan_stop(local, sched_scan_sdata);
1390                 if (!ret)
1391                         RCU_INIT_POINTER(local->sched_scan_sdata, NULL);
1392         }
1393 
1394         return ret;
1395 }
1396 
1397 void ieee80211_sched_scan_results(struct ieee80211_hw *hw)
1398 {
1399         struct ieee80211_local *local = hw_to_local(hw);
1400 
1401         trace_api_sched_scan_results(local);
1402 
1403         cfg80211_sched_scan_results(hw->wiphy, 0);
1404 }
1405 EXPORT_SYMBOL(ieee80211_sched_scan_results);
1406 
1407 void ieee80211_sched_scan_end(struct ieee80211_local *local)
1408 {
1409         lockdep_assert_wiphy(local->hw.wiphy);
1410 
1411         if (!rcu_access_pointer(local->sched_scan_sdata))
1412                 return;
1413 
1414         RCU_INIT_POINTER(local->sched_scan_sdata, NULL);
1415 
1416         /* If sched scan was aborted by the driver. */
1417         RCU_INIT_POINTER(local->sched_scan_req, NULL);
1418 
1419         cfg80211_sched_scan_stopped_locked(local->hw.wiphy, 0);
1420 }
1421 
1422 void ieee80211_sched_scan_stopped_work(struct wiphy *wiphy,
1423                                        struct wiphy_work *work)
1424 {
1425         struct ieee80211_local *local =
1426                 container_of(work, struct ieee80211_local,
1427                              sched_scan_stopped_work);
1428 
1429         ieee80211_sched_scan_end(local);
1430 }
1431 
1432 void ieee80211_sched_scan_stopped(struct ieee80211_hw *hw)
1433 {
1434         struct ieee80211_local *local = hw_to_local(hw);
1435 
1436         trace_api_sched_scan_stopped(local);
1437 
1438         /*
1439          * this shouldn't really happen, so for simplicity
1440          * simply ignore it, and let mac80211 reconfigure
1441          * the sched scan later on.
1442          */
1443         if (local->in_reconfig)
1444                 return;
1445 
1446         wiphy_work_queue(hw->wiphy, &local->sched_scan_stopped_work);
1447 }
1448 EXPORT_SYMBOL(ieee80211_sched_scan_stopped);
1449 

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