xref: /openbmc/linux/net/mac80211/scan.c (revision c1c50ca7)
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) 2018-2023 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.scan_width = NL80211_BSS_CHAN_WIDTH_20;
191 	if (rx_status->bw == RATE_INFO_BW_5)
192 		bss_meta.scan_width = NL80211_BSS_CHAN_WIDTH_5;
193 	else if (rx_status->bw == RATE_INFO_BW_10)
194 		bss_meta.scan_width = NL80211_BSS_CHAN_WIDTH_10;
195 
196 	bss_meta.chan = channel;
197 
198 	rcu_read_lock();
199 	scan_sdata = rcu_dereference(local->scan_sdata);
200 	if (scan_sdata && scan_sdata->vif.type == NL80211_IFTYPE_STATION &&
201 	    scan_sdata->vif.cfg.assoc &&
202 	    ieee80211_have_rx_timestamp(rx_status)) {
203 		bss_meta.parent_tsf =
204 			ieee80211_calculate_rx_timestamp(local, rx_status,
205 							 len + FCS_LEN, 24);
206 		ether_addr_copy(bss_meta.parent_bssid,
207 				scan_sdata->vif.bss_conf.bssid);
208 	}
209 	rcu_read_unlock();
210 
211 	cbss = cfg80211_inform_bss_frame_data(local->hw.wiphy, &bss_meta,
212 					      mgmt, len, GFP_ATOMIC);
213 	if (!cbss)
214 		return NULL;
215 
216 	/* In case the signal is invalid update the status */
217 	signal_valid = channel == cbss->channel;
218 	if (!signal_valid)
219 		rx_status->flag |= RX_FLAG_NO_SIGNAL_VAL;
220 
221 	return (void *)cbss->priv;
222 }
223 
224 static bool ieee80211_scan_accept_presp(struct ieee80211_sub_if_data *sdata,
225 					u32 scan_flags, const u8 *da)
226 {
227 	if (!sdata)
228 		return false;
229 	/* accept broadcast for OCE */
230 	if (scan_flags & NL80211_SCAN_FLAG_ACCEPT_BCAST_PROBE_RESP &&
231 	    is_broadcast_ether_addr(da))
232 		return true;
233 	if (scan_flags & NL80211_SCAN_FLAG_RANDOM_ADDR)
234 		return true;
235 	return ether_addr_equal(da, sdata->vif.addr);
236 }
237 
238 void ieee80211_scan_rx(struct ieee80211_local *local, struct sk_buff *skb)
239 {
240 	struct ieee80211_rx_status *rx_status = IEEE80211_SKB_RXCB(skb);
241 	struct ieee80211_sub_if_data *sdata1, *sdata2;
242 	struct ieee80211_mgmt *mgmt = (void *)skb->data;
243 	struct ieee80211_bss *bss;
244 	struct ieee80211_channel *channel;
245 	size_t min_hdr_len = offsetof(struct ieee80211_mgmt,
246 				      u.probe_resp.variable);
247 
248 	if (!ieee80211_is_probe_resp(mgmt->frame_control) &&
249 	    !ieee80211_is_beacon(mgmt->frame_control) &&
250 	    !ieee80211_is_s1g_beacon(mgmt->frame_control))
251 		return;
252 
253 	if (ieee80211_is_s1g_beacon(mgmt->frame_control)) {
254 		if (ieee80211_is_s1g_short_beacon(mgmt->frame_control))
255 			min_hdr_len = offsetof(struct ieee80211_ext,
256 					       u.s1g_short_beacon.variable);
257 		else
258 			min_hdr_len = offsetof(struct ieee80211_ext,
259 					       u.s1g_beacon);
260 	}
261 
262 	if (skb->len < min_hdr_len)
263 		return;
264 
265 	sdata1 = rcu_dereference(local->scan_sdata);
266 	sdata2 = rcu_dereference(local->sched_scan_sdata);
267 
268 	if (likely(!sdata1 && !sdata2))
269 		return;
270 
271 	if (test_and_clear_bit(SCAN_BEACON_WAIT, &local->scanning)) {
272 		/*
273 		 * we were passive scanning because of radar/no-IR, but
274 		 * the beacon/proberesp rx gives us an opportunity to upgrade
275 		 * to active scan
276 		 */
277 		set_bit(SCAN_BEACON_DONE, &local->scanning);
278 		wiphy_delayed_work_queue(local->hw.wiphy, &local->scan_work, 0);
279 	}
280 
281 	if (ieee80211_is_probe_resp(mgmt->frame_control)) {
282 		struct cfg80211_scan_request *scan_req;
283 		struct cfg80211_sched_scan_request *sched_scan_req;
284 		u32 scan_req_flags = 0, sched_scan_req_flags = 0;
285 
286 		scan_req = rcu_dereference(local->scan_req);
287 		sched_scan_req = rcu_dereference(local->sched_scan_req);
288 
289 		if (scan_req)
290 			scan_req_flags = scan_req->flags;
291 
292 		if (sched_scan_req)
293 			sched_scan_req_flags = sched_scan_req->flags;
294 
295 		/* ignore ProbeResp to foreign address or non-bcast (OCE)
296 		 * unless scanning with randomised address
297 		 */
298 		if (!ieee80211_scan_accept_presp(sdata1, scan_req_flags,
299 						 mgmt->da) &&
300 		    !ieee80211_scan_accept_presp(sdata2, sched_scan_req_flags,
301 						 mgmt->da))
302 			return;
303 	}
304 
305 	channel = ieee80211_get_channel_khz(local->hw.wiphy,
306 					ieee80211_rx_status_to_khz(rx_status));
307 
308 	if (!channel || channel->flags & IEEE80211_CHAN_DISABLED)
309 		return;
310 
311 	bss = ieee80211_bss_info_update(local, rx_status,
312 					mgmt, skb->len,
313 					channel);
314 	if (bss)
315 		ieee80211_rx_bss_put(local, bss);
316 }
317 
318 static void
319 ieee80211_prepare_scan_chandef(struct cfg80211_chan_def *chandef,
320 			       enum nl80211_bss_scan_width scan_width)
321 {
322 	memset(chandef, 0, sizeof(*chandef));
323 	switch (scan_width) {
324 	case NL80211_BSS_CHAN_WIDTH_5:
325 		chandef->width = NL80211_CHAN_WIDTH_5;
326 		break;
327 	case NL80211_BSS_CHAN_WIDTH_10:
328 		chandef->width = NL80211_CHAN_WIDTH_10;
329 		break;
330 	default:
331 		chandef->width = NL80211_CHAN_WIDTH_20_NOHT;
332 		break;
333 	}
334 }
335 
336 /* return false if no more work */
337 static bool ieee80211_prep_hw_scan(struct ieee80211_sub_if_data *sdata)
338 {
339 	struct ieee80211_local *local = sdata->local;
340 	struct cfg80211_scan_request *req;
341 	struct cfg80211_chan_def chandef;
342 	u8 bands_used = 0;
343 	int i, ielen, n_chans;
344 	u32 flags = 0;
345 
346 	req = rcu_dereference_protected(local->scan_req,
347 					lockdep_is_held(&local->mtx));
348 
349 	if (test_bit(SCAN_HW_CANCELLED, &local->scanning))
350 		return false;
351 
352 	if (ieee80211_hw_check(&local->hw, SINGLE_SCAN_ON_ALL_BANDS)) {
353 		for (i = 0; i < req->n_channels; i++) {
354 			local->hw_scan_req->req.channels[i] = req->channels[i];
355 			bands_used |= BIT(req->channels[i]->band);
356 		}
357 
358 		n_chans = req->n_channels;
359 	} else {
360 		do {
361 			if (local->hw_scan_band == NUM_NL80211_BANDS)
362 				return false;
363 
364 			n_chans = 0;
365 
366 			for (i = 0; i < req->n_channels; i++) {
367 				if (req->channels[i]->band !=
368 				    local->hw_scan_band)
369 					continue;
370 				local->hw_scan_req->req.channels[n_chans] =
371 							req->channels[i];
372 				n_chans++;
373 				bands_used |= BIT(req->channels[i]->band);
374 			}
375 
376 			local->hw_scan_band++;
377 		} while (!n_chans);
378 	}
379 
380 	local->hw_scan_req->req.n_channels = n_chans;
381 	ieee80211_prepare_scan_chandef(&chandef, req->scan_width);
382 
383 	if (req->flags & NL80211_SCAN_FLAG_MIN_PREQ_CONTENT)
384 		flags |= IEEE80211_PROBE_FLAG_MIN_CONTENT;
385 
386 	ielen = ieee80211_build_preq_ies(sdata,
387 					 (u8 *)local->hw_scan_req->req.ie,
388 					 local->hw_scan_ies_bufsize,
389 					 &local->hw_scan_req->ies,
390 					 req->ie, req->ie_len,
391 					 bands_used, req->rates, &chandef,
392 					 flags);
393 	local->hw_scan_req->req.ie_len = ielen;
394 	local->hw_scan_req->req.no_cck = req->no_cck;
395 	ether_addr_copy(local->hw_scan_req->req.mac_addr, req->mac_addr);
396 	ether_addr_copy(local->hw_scan_req->req.mac_addr_mask,
397 			req->mac_addr_mask);
398 	ether_addr_copy(local->hw_scan_req->req.bssid, req->bssid);
399 
400 	return true;
401 }
402 
403 static void __ieee80211_scan_completed(struct ieee80211_hw *hw, bool aborted)
404 {
405 	struct ieee80211_local *local = hw_to_local(hw);
406 	bool hw_scan = test_bit(SCAN_HW_SCANNING, &local->scanning);
407 	bool was_scanning = local->scanning;
408 	struct cfg80211_scan_request *scan_req;
409 	struct ieee80211_sub_if_data *scan_sdata;
410 	struct ieee80211_sub_if_data *sdata;
411 
412 	lockdep_assert_held(&local->mtx);
413 
414 	/*
415 	 * It's ok to abort a not-yet-running scan (that
416 	 * we have one at all will be verified by checking
417 	 * local->scan_req next), but not to complete it
418 	 * successfully.
419 	 */
420 	if (WARN_ON(!local->scanning && !aborted))
421 		aborted = true;
422 
423 	if (WARN_ON(!local->scan_req))
424 		return;
425 
426 	scan_sdata = rcu_dereference_protected(local->scan_sdata,
427 					       lockdep_is_held(&local->mtx));
428 
429 	if (hw_scan && !aborted &&
430 	    !ieee80211_hw_check(&local->hw, SINGLE_SCAN_ON_ALL_BANDS) &&
431 	    ieee80211_prep_hw_scan(scan_sdata)) {
432 		int rc;
433 
434 		rc = drv_hw_scan(local,
435 			rcu_dereference_protected(local->scan_sdata,
436 						  lockdep_is_held(&local->mtx)),
437 			local->hw_scan_req);
438 
439 		if (rc == 0)
440 			return;
441 
442 		/* HW scan failed and is going to be reported as aborted,
443 		 * so clear old scan info.
444 		 */
445 		memset(&local->scan_info, 0, sizeof(local->scan_info));
446 		aborted = true;
447 	}
448 
449 	kfree(local->hw_scan_req);
450 	local->hw_scan_req = NULL;
451 
452 	scan_req = rcu_dereference_protected(local->scan_req,
453 					     lockdep_is_held(&local->mtx));
454 
455 	RCU_INIT_POINTER(local->scan_req, NULL);
456 	RCU_INIT_POINTER(local->scan_sdata, NULL);
457 
458 	local->scanning = 0;
459 	local->scan_chandef.chan = NULL;
460 
461 	synchronize_rcu();
462 
463 	if (scan_req != local->int_scan_req) {
464 		local->scan_info.aborted = aborted;
465 		cfg80211_scan_done(scan_req, &local->scan_info);
466 	}
467 
468 	/* Set power back to normal operating levels. */
469 	ieee80211_hw_config(local, 0);
470 
471 	if (!hw_scan && was_scanning) {
472 		ieee80211_configure_filter(local);
473 		drv_sw_scan_complete(local, scan_sdata);
474 		ieee80211_offchannel_return(local);
475 	}
476 
477 	ieee80211_recalc_idle(local);
478 
479 	ieee80211_mlme_notify_scan_completed(local);
480 	ieee80211_ibss_notify_scan_completed(local);
481 
482 	/* Requeue all the work that might have been ignored while
483 	 * the scan was in progress; if there was none this will
484 	 * just be a no-op for the particular interface.
485 	 */
486 	list_for_each_entry_rcu(sdata, &local->interfaces, list) {
487 		if (ieee80211_sdata_running(sdata))
488 			wiphy_work_queue(sdata->local->hw.wiphy, &sdata->work);
489 	}
490 
491 	if (was_scanning)
492 		ieee80211_start_next_roc(local);
493 }
494 
495 void ieee80211_scan_completed(struct ieee80211_hw *hw,
496 			      struct cfg80211_scan_info *info)
497 {
498 	struct ieee80211_local *local = hw_to_local(hw);
499 
500 	trace_api_scan_completed(local, info->aborted);
501 
502 	set_bit(SCAN_COMPLETED, &local->scanning);
503 	if (info->aborted)
504 		set_bit(SCAN_ABORTED, &local->scanning);
505 
506 	memcpy(&local->scan_info, info, sizeof(*info));
507 
508 	wiphy_delayed_work_queue(local->hw.wiphy, &local->scan_work, 0);
509 }
510 EXPORT_SYMBOL(ieee80211_scan_completed);
511 
512 static int ieee80211_start_sw_scan(struct ieee80211_local *local,
513 				   struct ieee80211_sub_if_data *sdata)
514 {
515 	/* Software scan is not supported in multi-channel cases */
516 	if (local->use_chanctx)
517 		return -EOPNOTSUPP;
518 
519 	/*
520 	 * Hardware/driver doesn't support hw_scan, so use software
521 	 * scanning instead. First send a nullfunc frame with power save
522 	 * bit on so that AP will buffer the frames for us while we are not
523 	 * listening, then send probe requests to each channel and wait for
524 	 * the responses. After all channels are scanned, tune back to the
525 	 * original channel and send a nullfunc frame with power save bit
526 	 * off to trigger the AP to send us all the buffered frames.
527 	 *
528 	 * Note that while local->sw_scanning is true everything else but
529 	 * nullfunc frames and probe requests will be dropped in
530 	 * ieee80211_tx_h_check_assoc().
531 	 */
532 	drv_sw_scan_start(local, sdata, local->scan_addr);
533 
534 	local->leave_oper_channel_time = jiffies;
535 	local->next_scan_state = SCAN_DECISION;
536 	local->scan_channel_idx = 0;
537 
538 	ieee80211_offchannel_stop_vifs(local);
539 
540 	/* ensure nullfunc is transmitted before leaving operating channel */
541 	ieee80211_flush_queues(local, NULL, false);
542 
543 	ieee80211_configure_filter(local);
544 
545 	/* We need to set power level at maximum rate for scanning. */
546 	ieee80211_hw_config(local, 0);
547 
548 	wiphy_delayed_work_queue(local->hw.wiphy, &local->scan_work, 0);
549 
550 	return 0;
551 }
552 
553 static bool __ieee80211_can_leave_ch(struct ieee80211_sub_if_data *sdata)
554 {
555 	struct ieee80211_local *local = sdata->local;
556 	struct ieee80211_sub_if_data *sdata_iter;
557 
558 	if (!ieee80211_is_radar_required(local))
559 		return true;
560 
561 	if (!regulatory_pre_cac_allowed(local->hw.wiphy))
562 		return false;
563 
564 	mutex_lock(&local->iflist_mtx);
565 	list_for_each_entry(sdata_iter, &local->interfaces, list) {
566 		if (sdata_iter->wdev.cac_started) {
567 			mutex_unlock(&local->iflist_mtx);
568 			return false;
569 		}
570 	}
571 	mutex_unlock(&local->iflist_mtx);
572 
573 	return true;
574 }
575 
576 static bool ieee80211_can_scan(struct ieee80211_local *local,
577 			       struct ieee80211_sub_if_data *sdata)
578 {
579 	if (!__ieee80211_can_leave_ch(sdata))
580 		return false;
581 
582 	if (!list_empty(&local->roc_list))
583 		return false;
584 
585 	if (sdata->vif.type == NL80211_IFTYPE_STATION &&
586 	    sdata->u.mgd.flags & IEEE80211_STA_CONNECTION_POLL)
587 		return false;
588 
589 	return true;
590 }
591 
592 void ieee80211_run_deferred_scan(struct ieee80211_local *local)
593 {
594 	lockdep_assert_held(&local->mtx);
595 
596 	if (!local->scan_req || local->scanning)
597 		return;
598 
599 	if (!ieee80211_can_scan(local,
600 				rcu_dereference_protected(
601 					local->scan_sdata,
602 					lockdep_is_held(&local->mtx))))
603 		return;
604 
605 	wiphy_delayed_work_queue(local->hw.wiphy, &local->scan_work,
606 				 round_jiffies_relative(0));
607 }
608 
609 static void ieee80211_send_scan_probe_req(struct ieee80211_sub_if_data *sdata,
610 					  const u8 *src, const u8 *dst,
611 					  const u8 *ssid, size_t ssid_len,
612 					  const u8 *ie, size_t ie_len,
613 					  u32 ratemask, u32 flags, u32 tx_flags,
614 					  struct ieee80211_channel *channel)
615 {
616 	struct sk_buff *skb;
617 
618 	skb = ieee80211_build_probe_req(sdata, src, dst, ratemask, channel,
619 					ssid, ssid_len,
620 					ie, ie_len, flags);
621 
622 	if (skb) {
623 		if (flags & IEEE80211_PROBE_FLAG_RANDOM_SN) {
624 			struct ieee80211_hdr *hdr = (void *)skb->data;
625 			struct ieee80211_tx_info *info = IEEE80211_SKB_CB(skb);
626 			u16 sn = get_random_u16();
627 
628 			info->control.flags |= IEEE80211_TX_CTRL_NO_SEQNO;
629 			hdr->seq_ctrl =
630 				cpu_to_le16(IEEE80211_SN_TO_SEQ(sn));
631 		}
632 		IEEE80211_SKB_CB(skb)->flags |= tx_flags;
633 		ieee80211_tx_skb_tid_band(sdata, skb, 7, channel->band);
634 	}
635 }
636 
637 static void ieee80211_scan_state_send_probe(struct ieee80211_local *local,
638 					    unsigned long *next_delay)
639 {
640 	int i;
641 	struct ieee80211_sub_if_data *sdata;
642 	struct cfg80211_scan_request *scan_req;
643 	enum nl80211_band band = local->hw.conf.chandef.chan->band;
644 	u32 flags = 0, tx_flags;
645 
646 	scan_req = rcu_dereference_protected(local->scan_req,
647 					     lockdep_is_held(&local->mtx));
648 
649 	tx_flags = IEEE80211_TX_INTFL_OFFCHAN_TX_OK;
650 	if (scan_req->no_cck)
651 		tx_flags |= IEEE80211_TX_CTL_NO_CCK_RATE;
652 	if (scan_req->flags & NL80211_SCAN_FLAG_MIN_PREQ_CONTENT)
653 		flags |= IEEE80211_PROBE_FLAG_MIN_CONTENT;
654 	if (scan_req->flags & NL80211_SCAN_FLAG_RANDOM_SN)
655 		flags |= IEEE80211_PROBE_FLAG_RANDOM_SN;
656 
657 	sdata = rcu_dereference_protected(local->scan_sdata,
658 					  lockdep_is_held(&local->mtx));
659 
660 	for (i = 0; i < scan_req->n_ssids; i++)
661 		ieee80211_send_scan_probe_req(
662 			sdata, local->scan_addr, scan_req->bssid,
663 			scan_req->ssids[i].ssid, scan_req->ssids[i].ssid_len,
664 			scan_req->ie, scan_req->ie_len,
665 			scan_req->rates[band], flags,
666 			tx_flags, local->hw.conf.chandef.chan);
667 
668 	/*
669 	 * After sending probe requests, wait for probe responses
670 	 * on the channel.
671 	 */
672 	*next_delay = IEEE80211_CHANNEL_TIME;
673 	local->next_scan_state = SCAN_DECISION;
674 }
675 
676 static int __ieee80211_start_scan(struct ieee80211_sub_if_data *sdata,
677 				  struct cfg80211_scan_request *req)
678 {
679 	struct ieee80211_local *local = sdata->local;
680 	bool hw_scan = local->ops->hw_scan;
681 	int rc;
682 
683 	lockdep_assert_held(&local->mtx);
684 
685 	if (local->scan_req)
686 		return -EBUSY;
687 
688 	if (!__ieee80211_can_leave_ch(sdata))
689 		return -EBUSY;
690 
691 	if (!ieee80211_can_scan(local, sdata)) {
692 		/* wait for the work to finish/time out */
693 		rcu_assign_pointer(local->scan_req, req);
694 		rcu_assign_pointer(local->scan_sdata, sdata);
695 		return 0;
696 	}
697 
698  again:
699 	if (hw_scan) {
700 		u8 *ies;
701 
702 		local->hw_scan_ies_bufsize = local->scan_ies_len + req->ie_len;
703 
704 		if (ieee80211_hw_check(&local->hw, SINGLE_SCAN_ON_ALL_BANDS)) {
705 			int i, n_bands = 0;
706 			u8 bands_counted = 0;
707 
708 			for (i = 0; i < req->n_channels; i++) {
709 				if (bands_counted & BIT(req->channels[i]->band))
710 					continue;
711 				bands_counted |= BIT(req->channels[i]->band);
712 				n_bands++;
713 			}
714 
715 			local->hw_scan_ies_bufsize *= n_bands;
716 		}
717 
718 		local->hw_scan_req = kmalloc(
719 				sizeof(*local->hw_scan_req) +
720 				req->n_channels * sizeof(req->channels[0]) +
721 				local->hw_scan_ies_bufsize, GFP_KERNEL);
722 		if (!local->hw_scan_req)
723 			return -ENOMEM;
724 
725 		local->hw_scan_req->req.ssids = req->ssids;
726 		local->hw_scan_req->req.n_ssids = req->n_ssids;
727 		ies = (u8 *)local->hw_scan_req +
728 			sizeof(*local->hw_scan_req) +
729 			req->n_channels * sizeof(req->channels[0]);
730 		local->hw_scan_req->req.ie = ies;
731 		local->hw_scan_req->req.flags = req->flags;
732 		eth_broadcast_addr(local->hw_scan_req->req.bssid);
733 		local->hw_scan_req->req.duration = req->duration;
734 		local->hw_scan_req->req.duration_mandatory =
735 			req->duration_mandatory;
736 
737 		local->hw_scan_band = 0;
738 		local->hw_scan_req->req.n_6ghz_params = req->n_6ghz_params;
739 		local->hw_scan_req->req.scan_6ghz_params =
740 			req->scan_6ghz_params;
741 		local->hw_scan_req->req.scan_6ghz = req->scan_6ghz;
742 
743 		/*
744 		 * After allocating local->hw_scan_req, we must
745 		 * go through until ieee80211_prep_hw_scan(), so
746 		 * anything that might be changed here and leave
747 		 * this function early must not go after this
748 		 * allocation.
749 		 */
750 	}
751 
752 	rcu_assign_pointer(local->scan_req, req);
753 	rcu_assign_pointer(local->scan_sdata, sdata);
754 
755 	if (req->flags & NL80211_SCAN_FLAG_RANDOM_ADDR)
756 		get_random_mask_addr(local->scan_addr,
757 				     req->mac_addr,
758 				     req->mac_addr_mask);
759 	else
760 		memcpy(local->scan_addr, sdata->vif.addr, ETH_ALEN);
761 
762 	if (hw_scan) {
763 		__set_bit(SCAN_HW_SCANNING, &local->scanning);
764 	} else if ((req->n_channels == 1) &&
765 		   (req->channels[0] == local->_oper_chandef.chan)) {
766 		/*
767 		 * If we are scanning only on the operating channel
768 		 * then we do not need to stop normal activities
769 		 */
770 		unsigned long next_delay;
771 
772 		__set_bit(SCAN_ONCHANNEL_SCANNING, &local->scanning);
773 
774 		ieee80211_recalc_idle(local);
775 
776 		/* Notify driver scan is starting, keep order of operations
777 		 * same as normal software scan, in case that matters. */
778 		drv_sw_scan_start(local, sdata, local->scan_addr);
779 
780 		ieee80211_configure_filter(local); /* accept probe-responses */
781 
782 		/* We need to ensure power level is at max for scanning. */
783 		ieee80211_hw_config(local, 0);
784 
785 		if ((req->channels[0]->flags & (IEEE80211_CHAN_NO_IR |
786 						IEEE80211_CHAN_RADAR)) ||
787 		    !req->n_ssids) {
788 			next_delay = IEEE80211_PASSIVE_CHANNEL_TIME;
789 			if (req->n_ssids)
790 				set_bit(SCAN_BEACON_WAIT, &local->scanning);
791 		} else {
792 			ieee80211_scan_state_send_probe(local, &next_delay);
793 			next_delay = IEEE80211_CHANNEL_TIME;
794 		}
795 
796 		/* Now, just wait a bit and we are all done! */
797 		wiphy_delayed_work_queue(local->hw.wiphy, &local->scan_work,
798 					 next_delay);
799 		return 0;
800 	} else {
801 		/* Do normal software scan */
802 		__set_bit(SCAN_SW_SCANNING, &local->scanning);
803 	}
804 
805 	ieee80211_recalc_idle(local);
806 
807 	if (hw_scan) {
808 		WARN_ON(!ieee80211_prep_hw_scan(sdata));
809 		rc = drv_hw_scan(local, sdata, local->hw_scan_req);
810 	} else {
811 		rc = ieee80211_start_sw_scan(local, sdata);
812 	}
813 
814 	if (rc) {
815 		kfree(local->hw_scan_req);
816 		local->hw_scan_req = NULL;
817 		local->scanning = 0;
818 
819 		ieee80211_recalc_idle(local);
820 
821 		local->scan_req = NULL;
822 		RCU_INIT_POINTER(local->scan_sdata, NULL);
823 	}
824 
825 	if (hw_scan && rc == 1) {
826 		/*
827 		 * we can't fall back to software for P2P-GO
828 		 * as it must update NoA etc.
829 		 */
830 		if (ieee80211_vif_type_p2p(&sdata->vif) ==
831 				NL80211_IFTYPE_P2P_GO)
832 			return -EOPNOTSUPP;
833 		hw_scan = false;
834 		goto again;
835 	}
836 
837 	return rc;
838 }
839 
840 static unsigned long
841 ieee80211_scan_get_channel_time(struct ieee80211_channel *chan)
842 {
843 	/*
844 	 * TODO: channel switching also consumes quite some time,
845 	 * add that delay as well to get a better estimation
846 	 */
847 	if (chan->flags & (IEEE80211_CHAN_NO_IR | IEEE80211_CHAN_RADAR))
848 		return IEEE80211_PASSIVE_CHANNEL_TIME;
849 	return IEEE80211_PROBE_DELAY + IEEE80211_CHANNEL_TIME;
850 }
851 
852 static void ieee80211_scan_state_decision(struct ieee80211_local *local,
853 					  unsigned long *next_delay)
854 {
855 	bool associated = false;
856 	bool tx_empty = true;
857 	bool bad_latency;
858 	struct ieee80211_sub_if_data *sdata;
859 	struct ieee80211_channel *next_chan;
860 	enum mac80211_scan_state next_scan_state;
861 	struct cfg80211_scan_request *scan_req;
862 
863 	/*
864 	 * check if at least one STA interface is associated,
865 	 * check if at least one STA interface has pending tx frames
866 	 * and grab the lowest used beacon interval
867 	 */
868 	mutex_lock(&local->iflist_mtx);
869 	list_for_each_entry(sdata, &local->interfaces, list) {
870 		if (!ieee80211_sdata_running(sdata))
871 			continue;
872 
873 		if (sdata->vif.type == NL80211_IFTYPE_STATION) {
874 			if (sdata->u.mgd.associated) {
875 				associated = true;
876 
877 				if (!qdisc_all_tx_empty(sdata->dev)) {
878 					tx_empty = false;
879 					break;
880 				}
881 			}
882 		}
883 	}
884 	mutex_unlock(&local->iflist_mtx);
885 
886 	scan_req = rcu_dereference_protected(local->scan_req,
887 					     lockdep_is_held(&local->mtx));
888 
889 	next_chan = scan_req->channels[local->scan_channel_idx];
890 
891 	/*
892 	 * we're currently scanning a different channel, let's
893 	 * see if we can scan another channel without interfering
894 	 * with the current traffic situation.
895 	 *
896 	 * Keep good latency, do not stay off-channel more than 125 ms.
897 	 */
898 
899 	bad_latency = time_after(jiffies +
900 				 ieee80211_scan_get_channel_time(next_chan),
901 				 local->leave_oper_channel_time + HZ / 8);
902 
903 	if (associated && !tx_empty) {
904 		if (scan_req->flags & NL80211_SCAN_FLAG_LOW_PRIORITY)
905 			next_scan_state = SCAN_ABORT;
906 		else
907 			next_scan_state = SCAN_SUSPEND;
908 	} else if (associated && bad_latency) {
909 		next_scan_state = SCAN_SUSPEND;
910 	} else {
911 		next_scan_state = SCAN_SET_CHANNEL;
912 	}
913 
914 	local->next_scan_state = next_scan_state;
915 
916 	*next_delay = 0;
917 }
918 
919 static void ieee80211_scan_state_set_channel(struct ieee80211_local *local,
920 					     unsigned long *next_delay)
921 {
922 	int skip;
923 	struct ieee80211_channel *chan;
924 	enum nl80211_bss_scan_width oper_scan_width;
925 	struct cfg80211_scan_request *scan_req;
926 
927 	scan_req = rcu_dereference_protected(local->scan_req,
928 					     lockdep_is_held(&local->mtx));
929 
930 	skip = 0;
931 	chan = scan_req->channels[local->scan_channel_idx];
932 
933 	local->scan_chandef.chan = chan;
934 	local->scan_chandef.center_freq1 = chan->center_freq;
935 	local->scan_chandef.freq1_offset = chan->freq_offset;
936 	local->scan_chandef.center_freq2 = 0;
937 
938 	/* For scanning on the S1G band, ignore scan_width (which is constant
939 	 * across all channels) for now since channel width is specific to each
940 	 * channel. Detect the required channel width here and likely revisit
941 	 * later. Maybe scan_width could be used to build the channel scan list?
942 	 */
943 	if (chan->band == NL80211_BAND_S1GHZ) {
944 		local->scan_chandef.width = ieee80211_s1g_channel_width(chan);
945 		goto set_channel;
946 	}
947 
948 	switch (scan_req->scan_width) {
949 	case NL80211_BSS_CHAN_WIDTH_5:
950 		local->scan_chandef.width = NL80211_CHAN_WIDTH_5;
951 		break;
952 	case NL80211_BSS_CHAN_WIDTH_10:
953 		local->scan_chandef.width = NL80211_CHAN_WIDTH_10;
954 		break;
955 	default:
956 	case NL80211_BSS_CHAN_WIDTH_20:
957 		/* If scanning on oper channel, use whatever channel-type
958 		 * is currently in use.
959 		 */
960 		oper_scan_width = cfg80211_chandef_to_scan_width(
961 					&local->_oper_chandef);
962 		if (chan == local->_oper_chandef.chan &&
963 		    oper_scan_width == scan_req->scan_width)
964 			local->scan_chandef = local->_oper_chandef;
965 		else
966 			local->scan_chandef.width = NL80211_CHAN_WIDTH_20_NOHT;
967 		break;
968 	case NL80211_BSS_CHAN_WIDTH_1:
969 	case NL80211_BSS_CHAN_WIDTH_2:
970 		/* shouldn't get here, S1G handled above */
971 		WARN_ON(1);
972 		break;
973 	}
974 
975 set_channel:
976 	if (ieee80211_hw_config(local, IEEE80211_CONF_CHANGE_CHANNEL))
977 		skip = 1;
978 
979 	/* advance state machine to next channel/band */
980 	local->scan_channel_idx++;
981 
982 	if (skip) {
983 		/* if we skip this channel return to the decision state */
984 		local->next_scan_state = SCAN_DECISION;
985 		return;
986 	}
987 
988 	/*
989 	 * Probe delay is used to update the NAV, cf. 11.1.3.2.2
990 	 * (which unfortunately doesn't say _why_ step a) is done,
991 	 * but it waits for the probe delay or until a frame is
992 	 * received - and the received frame would update the NAV).
993 	 * For now, we do not support waiting until a frame is
994 	 * received.
995 	 *
996 	 * In any case, it is not necessary for a passive scan.
997 	 */
998 	if ((chan->flags & (IEEE80211_CHAN_NO_IR | IEEE80211_CHAN_RADAR)) ||
999 	    !scan_req->n_ssids) {
1000 		*next_delay = IEEE80211_PASSIVE_CHANNEL_TIME;
1001 		local->next_scan_state = SCAN_DECISION;
1002 		if (scan_req->n_ssids)
1003 			set_bit(SCAN_BEACON_WAIT, &local->scanning);
1004 		return;
1005 	}
1006 
1007 	/* active scan, send probes */
1008 	*next_delay = IEEE80211_PROBE_DELAY;
1009 	local->next_scan_state = SCAN_SEND_PROBE;
1010 }
1011 
1012 static void ieee80211_scan_state_suspend(struct ieee80211_local *local,
1013 					 unsigned long *next_delay)
1014 {
1015 	/* switch back to the operating channel */
1016 	local->scan_chandef.chan = NULL;
1017 	ieee80211_hw_config(local, IEEE80211_CONF_CHANGE_CHANNEL);
1018 
1019 	/* disable PS */
1020 	ieee80211_offchannel_return(local);
1021 
1022 	*next_delay = HZ / 5;
1023 	/* afterwards, resume scan & go to next channel */
1024 	local->next_scan_state = SCAN_RESUME;
1025 }
1026 
1027 static void ieee80211_scan_state_resume(struct ieee80211_local *local,
1028 					unsigned long *next_delay)
1029 {
1030 	ieee80211_offchannel_stop_vifs(local);
1031 
1032 	if (local->ops->flush) {
1033 		ieee80211_flush_queues(local, NULL, false);
1034 		*next_delay = 0;
1035 	} else
1036 		*next_delay = HZ / 10;
1037 
1038 	/* remember when we left the operating channel */
1039 	local->leave_oper_channel_time = jiffies;
1040 
1041 	/* advance to the next channel to be scanned */
1042 	local->next_scan_state = SCAN_SET_CHANNEL;
1043 }
1044 
1045 void ieee80211_scan_work(struct wiphy *wiphy, struct wiphy_work *work)
1046 {
1047 	struct ieee80211_local *local =
1048 		container_of(work, struct ieee80211_local, scan_work.work);
1049 	struct ieee80211_sub_if_data *sdata;
1050 	struct cfg80211_scan_request *scan_req;
1051 	unsigned long next_delay = 0;
1052 	bool aborted;
1053 
1054 	mutex_lock(&local->mtx);
1055 
1056 	if (!ieee80211_can_run_worker(local)) {
1057 		aborted = true;
1058 		goto out_complete;
1059 	}
1060 
1061 	sdata = rcu_dereference_protected(local->scan_sdata,
1062 					  lockdep_is_held(&local->mtx));
1063 	scan_req = rcu_dereference_protected(local->scan_req,
1064 					     lockdep_is_held(&local->mtx));
1065 
1066 	/* When scanning on-channel, the first-callback means completed. */
1067 	if (test_bit(SCAN_ONCHANNEL_SCANNING, &local->scanning)) {
1068 		aborted = test_and_clear_bit(SCAN_ABORTED, &local->scanning);
1069 		goto out_complete;
1070 	}
1071 
1072 	if (test_and_clear_bit(SCAN_COMPLETED, &local->scanning)) {
1073 		aborted = test_and_clear_bit(SCAN_ABORTED, &local->scanning);
1074 		goto out_complete;
1075 	}
1076 
1077 	if (!sdata || !scan_req)
1078 		goto out;
1079 
1080 	if (!local->scanning) {
1081 		int rc;
1082 
1083 		RCU_INIT_POINTER(local->scan_req, NULL);
1084 		RCU_INIT_POINTER(local->scan_sdata, NULL);
1085 
1086 		rc = __ieee80211_start_scan(sdata, scan_req);
1087 		if (rc) {
1088 			/* need to complete scan in cfg80211 */
1089 			rcu_assign_pointer(local->scan_req, scan_req);
1090 			aborted = true;
1091 			goto out_complete;
1092 		} else
1093 			goto out;
1094 	}
1095 
1096 	clear_bit(SCAN_BEACON_WAIT, &local->scanning);
1097 
1098 	/*
1099 	 * as long as no delay is required advance immediately
1100 	 * without scheduling a new work
1101 	 */
1102 	do {
1103 		if (!ieee80211_sdata_running(sdata)) {
1104 			aborted = true;
1105 			goto out_complete;
1106 		}
1107 
1108 		if (test_and_clear_bit(SCAN_BEACON_DONE, &local->scanning) &&
1109 		    local->next_scan_state == SCAN_DECISION)
1110 			local->next_scan_state = SCAN_SEND_PROBE;
1111 
1112 		switch (local->next_scan_state) {
1113 		case SCAN_DECISION:
1114 			/* if no more bands/channels left, complete scan */
1115 			if (local->scan_channel_idx >= scan_req->n_channels) {
1116 				aborted = false;
1117 				goto out_complete;
1118 			}
1119 			ieee80211_scan_state_decision(local, &next_delay);
1120 			break;
1121 		case SCAN_SET_CHANNEL:
1122 			ieee80211_scan_state_set_channel(local, &next_delay);
1123 			break;
1124 		case SCAN_SEND_PROBE:
1125 			ieee80211_scan_state_send_probe(local, &next_delay);
1126 			break;
1127 		case SCAN_SUSPEND:
1128 			ieee80211_scan_state_suspend(local, &next_delay);
1129 			break;
1130 		case SCAN_RESUME:
1131 			ieee80211_scan_state_resume(local, &next_delay);
1132 			break;
1133 		case SCAN_ABORT:
1134 			aborted = true;
1135 			goto out_complete;
1136 		}
1137 	} while (next_delay == 0);
1138 
1139 	wiphy_delayed_work_queue(local->hw.wiphy, &local->scan_work,
1140 				 next_delay);
1141 	goto out;
1142 
1143 out_complete:
1144 	__ieee80211_scan_completed(&local->hw, aborted);
1145 out:
1146 	mutex_unlock(&local->mtx);
1147 }
1148 
1149 int ieee80211_request_scan(struct ieee80211_sub_if_data *sdata,
1150 			   struct cfg80211_scan_request *req)
1151 {
1152 	int res;
1153 
1154 	mutex_lock(&sdata->local->mtx);
1155 	res = __ieee80211_start_scan(sdata, req);
1156 	mutex_unlock(&sdata->local->mtx);
1157 
1158 	return res;
1159 }
1160 
1161 int ieee80211_request_ibss_scan(struct ieee80211_sub_if_data *sdata,
1162 				const u8 *ssid, u8 ssid_len,
1163 				struct ieee80211_channel **channels,
1164 				unsigned int n_channels,
1165 				enum nl80211_bss_scan_width scan_width)
1166 {
1167 	struct ieee80211_local *local = sdata->local;
1168 	int ret = -EBUSY, i, n_ch = 0;
1169 	enum nl80211_band band;
1170 
1171 	mutex_lock(&local->mtx);
1172 
1173 	/* busy scanning */
1174 	if (local->scan_req)
1175 		goto unlock;
1176 
1177 	/* fill internal scan request */
1178 	if (!channels) {
1179 		int max_n;
1180 
1181 		for (band = 0; band < NUM_NL80211_BANDS; band++) {
1182 			if (!local->hw.wiphy->bands[band] ||
1183 			    band == NL80211_BAND_6GHZ)
1184 				continue;
1185 
1186 			max_n = local->hw.wiphy->bands[band]->n_channels;
1187 			for (i = 0; i < max_n; i++) {
1188 				struct ieee80211_channel *tmp_ch =
1189 				    &local->hw.wiphy->bands[band]->channels[i];
1190 
1191 				if (tmp_ch->flags & (IEEE80211_CHAN_NO_IR |
1192 						     IEEE80211_CHAN_DISABLED))
1193 					continue;
1194 
1195 				local->int_scan_req->channels[n_ch] = tmp_ch;
1196 				n_ch++;
1197 			}
1198 		}
1199 
1200 		if (WARN_ON_ONCE(n_ch == 0))
1201 			goto unlock;
1202 
1203 		local->int_scan_req->n_channels = n_ch;
1204 	} else {
1205 		for (i = 0; i < n_channels; i++) {
1206 			if (channels[i]->flags & (IEEE80211_CHAN_NO_IR |
1207 						  IEEE80211_CHAN_DISABLED))
1208 				continue;
1209 
1210 			local->int_scan_req->channels[n_ch] = channels[i];
1211 			n_ch++;
1212 		}
1213 
1214 		if (WARN_ON_ONCE(n_ch == 0))
1215 			goto unlock;
1216 
1217 		local->int_scan_req->n_channels = n_ch;
1218 	}
1219 
1220 	local->int_scan_req->ssids = &local->scan_ssid;
1221 	local->int_scan_req->n_ssids = 1;
1222 	local->int_scan_req->scan_width = scan_width;
1223 	memcpy(local->int_scan_req->ssids[0].ssid, ssid, IEEE80211_MAX_SSID_LEN);
1224 	local->int_scan_req->ssids[0].ssid_len = ssid_len;
1225 
1226 	ret = __ieee80211_start_scan(sdata, sdata->local->int_scan_req);
1227  unlock:
1228 	mutex_unlock(&local->mtx);
1229 	return ret;
1230 }
1231 
1232 void ieee80211_scan_cancel(struct ieee80211_local *local)
1233 {
1234 	/* ensure a new scan cannot be queued */
1235 	lockdep_assert_wiphy(local->hw.wiphy);
1236 
1237 	/*
1238 	 * We are canceling software scan, or deferred scan that was not
1239 	 * yet really started (see __ieee80211_start_scan ).
1240 	 *
1241 	 * Regarding hardware scan:
1242 	 * - we can not call  __ieee80211_scan_completed() as when
1243 	 *   SCAN_HW_SCANNING bit is set this function change
1244 	 *   local->hw_scan_req to operate on 5G band, what race with
1245 	 *   driver which can use local->hw_scan_req
1246 	 *
1247 	 * - we can not cancel scan_work since driver can schedule it
1248 	 *   by ieee80211_scan_completed(..., true) to finish scan
1249 	 *
1250 	 * Hence we only call the cancel_hw_scan() callback, but the low-level
1251 	 * driver is still responsible for calling ieee80211_scan_completed()
1252 	 * after the scan was completed/aborted.
1253 	 */
1254 
1255 	mutex_lock(&local->mtx);
1256 	if (!local->scan_req)
1257 		goto out;
1258 
1259 	/*
1260 	 * We have a scan running and the driver already reported completion,
1261 	 * but the worker hasn't run yet or is stuck on the mutex - mark it as
1262 	 * cancelled.
1263 	 */
1264 	if (test_bit(SCAN_HW_SCANNING, &local->scanning) &&
1265 	    test_bit(SCAN_COMPLETED, &local->scanning)) {
1266 		set_bit(SCAN_HW_CANCELLED, &local->scanning);
1267 		goto out;
1268 	}
1269 
1270 	if (test_bit(SCAN_HW_SCANNING, &local->scanning)) {
1271 		/*
1272 		 * Make sure that __ieee80211_scan_completed doesn't trigger a
1273 		 * scan on another band.
1274 		 */
1275 		set_bit(SCAN_HW_CANCELLED, &local->scanning);
1276 		if (local->ops->cancel_hw_scan)
1277 			drv_cancel_hw_scan(local,
1278 				rcu_dereference_protected(local->scan_sdata,
1279 						lockdep_is_held(&local->mtx)));
1280 		goto out;
1281 	}
1282 
1283 	wiphy_delayed_work_cancel(local->hw.wiphy, &local->scan_work);
1284 	/* and clean up */
1285 	memset(&local->scan_info, 0, sizeof(local->scan_info));
1286 	__ieee80211_scan_completed(&local->hw, true);
1287 out:
1288 	mutex_unlock(&local->mtx);
1289 }
1290 
1291 int __ieee80211_request_sched_scan_start(struct ieee80211_sub_if_data *sdata,
1292 					struct cfg80211_sched_scan_request *req)
1293 {
1294 	struct ieee80211_local *local = sdata->local;
1295 	struct ieee80211_scan_ies sched_scan_ies = {};
1296 	struct cfg80211_chan_def chandef;
1297 	int ret, i, iebufsz, num_bands = 0;
1298 	u32 rate_masks[NUM_NL80211_BANDS] = {};
1299 	u8 bands_used = 0;
1300 	u8 *ie;
1301 	u32 flags = 0;
1302 
1303 	iebufsz = local->scan_ies_len + req->ie_len;
1304 
1305 	lockdep_assert_held(&local->mtx);
1306 
1307 	if (!local->ops->sched_scan_start)
1308 		return -ENOTSUPP;
1309 
1310 	for (i = 0; i < NUM_NL80211_BANDS; i++) {
1311 		if (local->hw.wiphy->bands[i]) {
1312 			bands_used |= BIT(i);
1313 			rate_masks[i] = (u32) -1;
1314 			num_bands++;
1315 		}
1316 	}
1317 
1318 	if (req->flags & NL80211_SCAN_FLAG_MIN_PREQ_CONTENT)
1319 		flags |= IEEE80211_PROBE_FLAG_MIN_CONTENT;
1320 
1321 	ie = kcalloc(iebufsz, num_bands, GFP_KERNEL);
1322 	if (!ie) {
1323 		ret = -ENOMEM;
1324 		goto out;
1325 	}
1326 
1327 	ieee80211_prepare_scan_chandef(&chandef, req->scan_width);
1328 
1329 	ieee80211_build_preq_ies(sdata, ie, num_bands * iebufsz,
1330 				 &sched_scan_ies, req->ie,
1331 				 req->ie_len, bands_used, rate_masks, &chandef,
1332 				 flags);
1333 
1334 	ret = drv_sched_scan_start(local, sdata, req, &sched_scan_ies);
1335 	if (ret == 0) {
1336 		rcu_assign_pointer(local->sched_scan_sdata, sdata);
1337 		rcu_assign_pointer(local->sched_scan_req, req);
1338 	}
1339 
1340 	kfree(ie);
1341 
1342 out:
1343 	if (ret) {
1344 		/* Clean in case of failure after HW restart or upon resume. */
1345 		RCU_INIT_POINTER(local->sched_scan_sdata, NULL);
1346 		RCU_INIT_POINTER(local->sched_scan_req, NULL);
1347 	}
1348 
1349 	return ret;
1350 }
1351 
1352 int ieee80211_request_sched_scan_start(struct ieee80211_sub_if_data *sdata,
1353 				       struct cfg80211_sched_scan_request *req)
1354 {
1355 	struct ieee80211_local *local = sdata->local;
1356 	int ret;
1357 
1358 	mutex_lock(&local->mtx);
1359 
1360 	if (rcu_access_pointer(local->sched_scan_sdata)) {
1361 		mutex_unlock(&local->mtx);
1362 		return -EBUSY;
1363 	}
1364 
1365 	ret = __ieee80211_request_sched_scan_start(sdata, req);
1366 
1367 	mutex_unlock(&local->mtx);
1368 	return ret;
1369 }
1370 
1371 int ieee80211_request_sched_scan_stop(struct ieee80211_local *local)
1372 {
1373 	struct ieee80211_sub_if_data *sched_scan_sdata;
1374 	int ret = -ENOENT;
1375 
1376 	mutex_lock(&local->mtx);
1377 
1378 	if (!local->ops->sched_scan_stop) {
1379 		ret = -ENOTSUPP;
1380 		goto out;
1381 	}
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->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 out:
1394 	mutex_unlock(&local->mtx);
1395 
1396 	return ret;
1397 }
1398 
1399 void ieee80211_sched_scan_results(struct ieee80211_hw *hw)
1400 {
1401 	struct ieee80211_local *local = hw_to_local(hw);
1402 
1403 	trace_api_sched_scan_results(local);
1404 
1405 	cfg80211_sched_scan_results(hw->wiphy, 0);
1406 }
1407 EXPORT_SYMBOL(ieee80211_sched_scan_results);
1408 
1409 void ieee80211_sched_scan_end(struct ieee80211_local *local)
1410 {
1411 	mutex_lock(&local->mtx);
1412 
1413 	if (!rcu_access_pointer(local->sched_scan_sdata)) {
1414 		mutex_unlock(&local->mtx);
1415 		return;
1416 	}
1417 
1418 	RCU_INIT_POINTER(local->sched_scan_sdata, NULL);
1419 
1420 	/* If sched scan was aborted by the driver. */
1421 	RCU_INIT_POINTER(local->sched_scan_req, NULL);
1422 
1423 	mutex_unlock(&local->mtx);
1424 
1425 	cfg80211_sched_scan_stopped_locked(local->hw.wiphy, 0);
1426 }
1427 
1428 void ieee80211_sched_scan_stopped_work(struct wiphy *wiphy,
1429 				       struct wiphy_work *work)
1430 {
1431 	struct ieee80211_local *local =
1432 		container_of(work, struct ieee80211_local,
1433 			     sched_scan_stopped_work);
1434 
1435 	ieee80211_sched_scan_end(local);
1436 }
1437 
1438 void ieee80211_sched_scan_stopped(struct ieee80211_hw *hw)
1439 {
1440 	struct ieee80211_local *local = hw_to_local(hw);
1441 
1442 	trace_api_sched_scan_stopped(local);
1443 
1444 	/*
1445 	 * this shouldn't really happen, so for simplicity
1446 	 * simply ignore it, and let mac80211 reconfigure
1447 	 * the sched scan later on.
1448 	 */
1449 	if (local->in_reconfig)
1450 		return;
1451 
1452 	wiphy_work_queue(hw->wiphy, &local->sched_scan_stopped_work);
1453 }
1454 EXPORT_SYMBOL(ieee80211_sched_scan_stopped);
1455