xref: /openbmc/linux/net/mac80211/scan.c (revision c6fddb28)
1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3  * Scanning implementation
4  *
5  * Copyright 2003, Jouni Malinen <jkmaline@cc.hut.fi>
6  * Copyright 2004, Instant802 Networks, Inc.
7  * Copyright 2005, Devicescape Software, Inc.
8  * Copyright 2006-2007	Jiri Benc <jbenc@suse.cz>
9  * Copyright 2007, Michael Wu <flamingice@sourmilk.net>
10  * Copyright 2013-2015  Intel Mobile Communications GmbH
11  * Copyright 2016-2017  Intel Deutschland GmbH
12  * Copyright (C) 2018-2019 Intel Corporation
13  */
14 
15 #include <linux/if_arp.h>
16 #include <linux/etherdevice.h>
17 #include <linux/rtnetlink.h>
18 #include <net/sch_generic.h>
19 #include <linux/slab.h>
20 #include <linux/export.h>
21 #include <linux/random.h>
22 #include <net/mac80211.h>
23 
24 #include "ieee80211_i.h"
25 #include "driver-ops.h"
26 #include "mesh.h"
27 
28 #define IEEE80211_PROBE_DELAY (HZ / 33)
29 #define IEEE80211_CHANNEL_TIME (HZ / 33)
30 #define IEEE80211_PASSIVE_CHANNEL_TIME (HZ / 9)
31 
32 void ieee80211_rx_bss_put(struct ieee80211_local *local,
33 			  struct ieee80211_bss *bss)
34 {
35 	if (!bss)
36 		return;
37 	cfg80211_put_bss(local->hw.wiphy,
38 			 container_of((void *)bss, struct cfg80211_bss, priv));
39 }
40 
41 static bool is_uapsd_supported(struct ieee802_11_elems *elems)
42 {
43 	u8 qos_info;
44 
45 	if (elems->wmm_info && elems->wmm_info_len == 7
46 	    && elems->wmm_info[5] == 1)
47 		qos_info = elems->wmm_info[6];
48 	else if (elems->wmm_param && elems->wmm_param_len == 24
49 		 && elems->wmm_param[5] == 1)
50 		qos_info = elems->wmm_param[6];
51 	else
52 		/* no valid wmm information or parameter element found */
53 		return false;
54 
55 	return qos_info & IEEE80211_WMM_IE_AP_QOSINFO_UAPSD;
56 }
57 
58 static void
59 ieee80211_update_bss_from_elems(struct ieee80211_local *local,
60 				struct ieee80211_bss *bss,
61 				struct ieee802_11_elems *elems,
62 				struct ieee80211_rx_status *rx_status,
63 				bool beacon)
64 {
65 	int clen, srlen;
66 
67 	if (beacon)
68 		bss->device_ts_beacon = rx_status->device_timestamp;
69 	else
70 		bss->device_ts_presp = rx_status->device_timestamp;
71 
72 	if (elems->parse_error) {
73 		if (beacon)
74 			bss->corrupt_data |= IEEE80211_BSS_CORRUPT_BEACON;
75 		else
76 			bss->corrupt_data |= IEEE80211_BSS_CORRUPT_PROBE_RESP;
77 	} else {
78 		if (beacon)
79 			bss->corrupt_data &= ~IEEE80211_BSS_CORRUPT_BEACON;
80 		else
81 			bss->corrupt_data &= ~IEEE80211_BSS_CORRUPT_PROBE_RESP;
82 	}
83 
84 	/* save the ERP value so that it is available at association time */
85 	if (elems->erp_info && (!elems->parse_error ||
86 				!(bss->valid_data & IEEE80211_BSS_VALID_ERP))) {
87 		bss->erp_value = elems->erp_info[0];
88 		bss->has_erp_value = true;
89 		if (!elems->parse_error)
90 			bss->valid_data |= IEEE80211_BSS_VALID_ERP;
91 	}
92 
93 	/* replace old supported rates if we get new values */
94 	if (!elems->parse_error ||
95 	    !(bss->valid_data & IEEE80211_BSS_VALID_RATES)) {
96 		srlen = 0;
97 		if (elems->supp_rates) {
98 			clen = IEEE80211_MAX_SUPP_RATES;
99 			if (clen > elems->supp_rates_len)
100 				clen = elems->supp_rates_len;
101 			memcpy(bss->supp_rates, elems->supp_rates, clen);
102 			srlen += clen;
103 		}
104 		if (elems->ext_supp_rates) {
105 			clen = IEEE80211_MAX_SUPP_RATES - srlen;
106 			if (clen > elems->ext_supp_rates_len)
107 				clen = elems->ext_supp_rates_len;
108 			memcpy(bss->supp_rates + srlen, elems->ext_supp_rates,
109 			       clen);
110 			srlen += clen;
111 		}
112 		if (srlen) {
113 			bss->supp_rates_len = srlen;
114 			if (!elems->parse_error)
115 				bss->valid_data |= IEEE80211_BSS_VALID_RATES;
116 		}
117 	}
118 
119 	if (!elems->parse_error ||
120 	    !(bss->valid_data & IEEE80211_BSS_VALID_WMM)) {
121 		bss->wmm_used = elems->wmm_param || elems->wmm_info;
122 		bss->uapsd_supported = is_uapsd_supported(elems);
123 		if (!elems->parse_error)
124 			bss->valid_data |= IEEE80211_BSS_VALID_WMM;
125 	}
126 
127 	if (beacon) {
128 		struct ieee80211_supported_band *sband =
129 			local->hw.wiphy->bands[rx_status->band];
130 		if (!(rx_status->encoding == RX_ENC_HT) &&
131 		    !(rx_status->encoding == RX_ENC_VHT))
132 			bss->beacon_rate =
133 				&sband->bitrates[rx_status->rate_idx];
134 	}
135 }
136 
137 struct ieee80211_bss *
138 ieee80211_bss_info_update(struct ieee80211_local *local,
139 			  struct ieee80211_rx_status *rx_status,
140 			  struct ieee80211_mgmt *mgmt, size_t len,
141 			  struct ieee80211_channel *channel)
142 {
143 	bool beacon = ieee80211_is_beacon(mgmt->frame_control);
144 	struct cfg80211_bss *cbss, *non_tx_cbss;
145 	struct ieee80211_bss *bss, *non_tx_bss;
146 	struct cfg80211_inform_bss bss_meta = {
147 		.boottime_ns = rx_status->boottime_ns,
148 	};
149 	bool signal_valid;
150 	struct ieee80211_sub_if_data *scan_sdata;
151 	struct ieee802_11_elems elems;
152 	size_t baselen;
153 	u8 *elements;
154 
155 	if (rx_status->flag & RX_FLAG_NO_SIGNAL_VAL)
156 		bss_meta.signal = 0; /* invalid signal indication */
157 	else if (ieee80211_hw_check(&local->hw, SIGNAL_DBM))
158 		bss_meta.signal = rx_status->signal * 100;
159 	else if (ieee80211_hw_check(&local->hw, SIGNAL_UNSPEC))
160 		bss_meta.signal = (rx_status->signal * 100) / local->hw.max_signal;
161 
162 	bss_meta.scan_width = NL80211_BSS_CHAN_WIDTH_20;
163 	if (rx_status->bw == RATE_INFO_BW_5)
164 		bss_meta.scan_width = NL80211_BSS_CHAN_WIDTH_5;
165 	else if (rx_status->bw == RATE_INFO_BW_10)
166 		bss_meta.scan_width = NL80211_BSS_CHAN_WIDTH_10;
167 
168 	bss_meta.chan = channel;
169 
170 	rcu_read_lock();
171 	scan_sdata = rcu_dereference(local->scan_sdata);
172 	if (scan_sdata && scan_sdata->vif.type == NL80211_IFTYPE_STATION &&
173 	    scan_sdata->vif.bss_conf.assoc &&
174 	    ieee80211_have_rx_timestamp(rx_status)) {
175 		bss_meta.parent_tsf =
176 			ieee80211_calculate_rx_timestamp(local, rx_status,
177 							 len + FCS_LEN, 24);
178 		ether_addr_copy(bss_meta.parent_bssid,
179 				scan_sdata->vif.bss_conf.bssid);
180 	}
181 	rcu_read_unlock();
182 
183 	cbss = cfg80211_inform_bss_frame_data(local->hw.wiphy, &bss_meta,
184 					      mgmt, len, GFP_ATOMIC);
185 	if (!cbss)
186 		return NULL;
187 
188 	if (ieee80211_is_probe_resp(mgmt->frame_control)) {
189 		elements = mgmt->u.probe_resp.variable;
190 		baselen = offsetof(struct ieee80211_mgmt,
191 				   u.probe_resp.variable);
192 	} else {
193 		baselen = offsetof(struct ieee80211_mgmt, u.beacon.variable);
194 		elements = mgmt->u.beacon.variable;
195 	}
196 
197 	if (baselen > len)
198 		return NULL;
199 
200 	ieee802_11_parse_elems(elements, len - baselen, false, &elems,
201 			       mgmt->bssid, cbss->bssid);
202 
203 	/* In case the signal is invalid update the status */
204 	signal_valid = channel == cbss->channel;
205 	if (!signal_valid)
206 		rx_status->flag |= RX_FLAG_NO_SIGNAL_VAL;
207 
208 	bss = (void *)cbss->priv;
209 	ieee80211_update_bss_from_elems(local, bss, &elems, rx_status, beacon);
210 
211 	list_for_each_entry(non_tx_cbss, &cbss->nontrans_list, nontrans_list) {
212 		non_tx_bss = (void *)non_tx_cbss->priv;
213 
214 		ieee80211_update_bss_from_elems(local, non_tx_bss, &elems,
215 						rx_status, beacon);
216 	}
217 
218 	return bss;
219 }
220 
221 static bool ieee80211_scan_accept_presp(struct ieee80211_sub_if_data *sdata,
222 					u32 scan_flags, const u8 *da)
223 {
224 	if (!sdata)
225 		return false;
226 	/* accept broadcast for OCE */
227 	if (scan_flags & NL80211_SCAN_FLAG_ACCEPT_BCAST_PROBE_RESP &&
228 	    is_broadcast_ether_addr(da))
229 		return true;
230 	if (scan_flags & NL80211_SCAN_FLAG_RANDOM_ADDR)
231 		return true;
232 	return ether_addr_equal(da, sdata->vif.addr);
233 }
234 
235 void ieee80211_scan_rx(struct ieee80211_local *local, struct sk_buff *skb)
236 {
237 	struct ieee80211_rx_status *rx_status = IEEE80211_SKB_RXCB(skb);
238 	struct ieee80211_sub_if_data *sdata1, *sdata2;
239 	struct ieee80211_mgmt *mgmt = (void *)skb->data;
240 	struct ieee80211_bss *bss;
241 	struct ieee80211_channel *channel;
242 
243 	if (skb->len < 24 ||
244 	    (!ieee80211_is_probe_resp(mgmt->frame_control) &&
245 	     !ieee80211_is_beacon(mgmt->frame_control)))
246 		return;
247 
248 	sdata1 = rcu_dereference(local->scan_sdata);
249 	sdata2 = rcu_dereference(local->sched_scan_sdata);
250 
251 	if (likely(!sdata1 && !sdata2))
252 		return;
253 
254 	if (ieee80211_is_probe_resp(mgmt->frame_control)) {
255 		struct cfg80211_scan_request *scan_req;
256 		struct cfg80211_sched_scan_request *sched_scan_req;
257 		u32 scan_req_flags = 0, sched_scan_req_flags = 0;
258 
259 		scan_req = rcu_dereference(local->scan_req);
260 		sched_scan_req = rcu_dereference(local->sched_scan_req);
261 
262 		if (scan_req)
263 			scan_req_flags = scan_req->flags;
264 
265 		if (sched_scan_req)
266 			sched_scan_req_flags = sched_scan_req->flags;
267 
268 		/* ignore ProbeResp to foreign address or non-bcast (OCE)
269 		 * unless scanning with randomised address
270 		 */
271 		if (!ieee80211_scan_accept_presp(sdata1, scan_req_flags,
272 						 mgmt->da) &&
273 		    !ieee80211_scan_accept_presp(sdata2, sched_scan_req_flags,
274 						 mgmt->da))
275 			return;
276 	}
277 
278 	channel = ieee80211_get_channel(local->hw.wiphy, rx_status->freq);
279 
280 	if (!channel || channel->flags & IEEE80211_CHAN_DISABLED)
281 		return;
282 
283 	bss = ieee80211_bss_info_update(local, rx_status,
284 					mgmt, skb->len,
285 					channel);
286 	if (bss)
287 		ieee80211_rx_bss_put(local, bss);
288 }
289 
290 static void
291 ieee80211_prepare_scan_chandef(struct cfg80211_chan_def *chandef,
292 			       enum nl80211_bss_scan_width scan_width)
293 {
294 	memset(chandef, 0, sizeof(*chandef));
295 	switch (scan_width) {
296 	case NL80211_BSS_CHAN_WIDTH_5:
297 		chandef->width = NL80211_CHAN_WIDTH_5;
298 		break;
299 	case NL80211_BSS_CHAN_WIDTH_10:
300 		chandef->width = NL80211_CHAN_WIDTH_10;
301 		break;
302 	default:
303 		chandef->width = NL80211_CHAN_WIDTH_20_NOHT;
304 		break;
305 	}
306 }
307 
308 /* return false if no more work */
309 static bool ieee80211_prep_hw_scan(struct ieee80211_local *local)
310 {
311 	struct cfg80211_scan_request *req;
312 	struct cfg80211_chan_def chandef;
313 	u8 bands_used = 0;
314 	int i, ielen, n_chans;
315 	u32 flags = 0;
316 
317 	req = rcu_dereference_protected(local->scan_req,
318 					lockdep_is_held(&local->mtx));
319 
320 	if (test_bit(SCAN_HW_CANCELLED, &local->scanning))
321 		return false;
322 
323 	if (ieee80211_hw_check(&local->hw, SINGLE_SCAN_ON_ALL_BANDS)) {
324 		for (i = 0; i < req->n_channels; i++) {
325 			local->hw_scan_req->req.channels[i] = req->channels[i];
326 			bands_used |= BIT(req->channels[i]->band);
327 		}
328 
329 		n_chans = req->n_channels;
330 	} else {
331 		do {
332 			if (local->hw_scan_band == NUM_NL80211_BANDS)
333 				return false;
334 
335 			n_chans = 0;
336 
337 			for (i = 0; i < req->n_channels; i++) {
338 				if (req->channels[i]->band !=
339 				    local->hw_scan_band)
340 					continue;
341 				local->hw_scan_req->req.channels[n_chans] =
342 							req->channels[i];
343 				n_chans++;
344 				bands_used |= BIT(req->channels[i]->band);
345 			}
346 
347 			local->hw_scan_band++;
348 		} while (!n_chans);
349 	}
350 
351 	local->hw_scan_req->req.n_channels = n_chans;
352 	ieee80211_prepare_scan_chandef(&chandef, req->scan_width);
353 
354 	if (req->flags & NL80211_SCAN_FLAG_MIN_PREQ_CONTENT)
355 		flags |= IEEE80211_PROBE_FLAG_MIN_CONTENT;
356 
357 	ielen = ieee80211_build_preq_ies(local,
358 					 (u8 *)local->hw_scan_req->req.ie,
359 					 local->hw_scan_ies_bufsize,
360 					 &local->hw_scan_req->ies,
361 					 req->ie, req->ie_len,
362 					 bands_used, req->rates, &chandef,
363 					 flags);
364 	local->hw_scan_req->req.ie_len = ielen;
365 	local->hw_scan_req->req.no_cck = req->no_cck;
366 	ether_addr_copy(local->hw_scan_req->req.mac_addr, req->mac_addr);
367 	ether_addr_copy(local->hw_scan_req->req.mac_addr_mask,
368 			req->mac_addr_mask);
369 	ether_addr_copy(local->hw_scan_req->req.bssid, req->bssid);
370 
371 	return true;
372 }
373 
374 static void __ieee80211_scan_completed(struct ieee80211_hw *hw, bool aborted)
375 {
376 	struct ieee80211_local *local = hw_to_local(hw);
377 	bool hw_scan = test_bit(SCAN_HW_SCANNING, &local->scanning);
378 	bool was_scanning = local->scanning;
379 	struct cfg80211_scan_request *scan_req;
380 	struct ieee80211_sub_if_data *scan_sdata;
381 	struct ieee80211_sub_if_data *sdata;
382 
383 	lockdep_assert_held(&local->mtx);
384 
385 	/*
386 	 * It's ok to abort a not-yet-running scan (that
387 	 * we have one at all will be verified by checking
388 	 * local->scan_req next), but not to complete it
389 	 * successfully.
390 	 */
391 	if (WARN_ON(!local->scanning && !aborted))
392 		aborted = true;
393 
394 	if (WARN_ON(!local->scan_req))
395 		return;
396 
397 	if (hw_scan && !aborted &&
398 	    !ieee80211_hw_check(&local->hw, SINGLE_SCAN_ON_ALL_BANDS) &&
399 	    ieee80211_prep_hw_scan(local)) {
400 		int rc;
401 
402 		rc = drv_hw_scan(local,
403 			rcu_dereference_protected(local->scan_sdata,
404 						  lockdep_is_held(&local->mtx)),
405 			local->hw_scan_req);
406 
407 		if (rc == 0)
408 			return;
409 
410 		/* HW scan failed and is going to be reported as aborted,
411 		 * so clear old scan info.
412 		 */
413 		memset(&local->scan_info, 0, sizeof(local->scan_info));
414 		aborted = true;
415 	}
416 
417 	kfree(local->hw_scan_req);
418 	local->hw_scan_req = NULL;
419 
420 	scan_req = rcu_dereference_protected(local->scan_req,
421 					     lockdep_is_held(&local->mtx));
422 
423 	if (scan_req != local->int_scan_req) {
424 		local->scan_info.aborted = aborted;
425 		cfg80211_scan_done(scan_req, &local->scan_info);
426 	}
427 	RCU_INIT_POINTER(local->scan_req, NULL);
428 
429 	scan_sdata = rcu_dereference_protected(local->scan_sdata,
430 					       lockdep_is_held(&local->mtx));
431 	RCU_INIT_POINTER(local->scan_sdata, NULL);
432 
433 	local->scanning = 0;
434 	local->scan_chandef.chan = NULL;
435 
436 	/* Set power back to normal operating levels. */
437 	ieee80211_hw_config(local, 0);
438 
439 	if (!hw_scan) {
440 		ieee80211_configure_filter(local);
441 		drv_sw_scan_complete(local, scan_sdata);
442 		ieee80211_offchannel_return(local);
443 	}
444 
445 	ieee80211_recalc_idle(local);
446 
447 	ieee80211_mlme_notify_scan_completed(local);
448 	ieee80211_ibss_notify_scan_completed(local);
449 
450 	/* Requeue all the work that might have been ignored while
451 	 * the scan was in progress; if there was none this will
452 	 * just be a no-op for the particular interface.
453 	 */
454 	list_for_each_entry_rcu(sdata, &local->interfaces, list) {
455 		if (ieee80211_sdata_running(sdata))
456 			ieee80211_queue_work(&sdata->local->hw, &sdata->work);
457 	}
458 
459 	if (was_scanning)
460 		ieee80211_start_next_roc(local);
461 }
462 
463 void ieee80211_scan_completed(struct ieee80211_hw *hw,
464 			      struct cfg80211_scan_info *info)
465 {
466 	struct ieee80211_local *local = hw_to_local(hw);
467 
468 	trace_api_scan_completed(local, info->aborted);
469 
470 	set_bit(SCAN_COMPLETED, &local->scanning);
471 	if (info->aborted)
472 		set_bit(SCAN_ABORTED, &local->scanning);
473 
474 	memcpy(&local->scan_info, info, sizeof(*info));
475 
476 	ieee80211_queue_delayed_work(&local->hw, &local->scan_work, 0);
477 }
478 EXPORT_SYMBOL(ieee80211_scan_completed);
479 
480 static int ieee80211_start_sw_scan(struct ieee80211_local *local,
481 				   struct ieee80211_sub_if_data *sdata)
482 {
483 	/* Software scan is not supported in multi-channel cases */
484 	if (local->use_chanctx)
485 		return -EOPNOTSUPP;
486 
487 	/*
488 	 * Hardware/driver doesn't support hw_scan, so use software
489 	 * scanning instead. First send a nullfunc frame with power save
490 	 * bit on so that AP will buffer the frames for us while we are not
491 	 * listening, then send probe requests to each channel and wait for
492 	 * the responses. After all channels are scanned, tune back to the
493 	 * original channel and send a nullfunc frame with power save bit
494 	 * off to trigger the AP to send us all the buffered frames.
495 	 *
496 	 * Note that while local->sw_scanning is true everything else but
497 	 * nullfunc frames and probe requests will be dropped in
498 	 * ieee80211_tx_h_check_assoc().
499 	 */
500 	drv_sw_scan_start(local, sdata, local->scan_addr);
501 
502 	local->leave_oper_channel_time = jiffies;
503 	local->next_scan_state = SCAN_DECISION;
504 	local->scan_channel_idx = 0;
505 
506 	ieee80211_offchannel_stop_vifs(local);
507 
508 	/* ensure nullfunc is transmitted before leaving operating channel */
509 	ieee80211_flush_queues(local, NULL, false);
510 
511 	ieee80211_configure_filter(local);
512 
513 	/* We need to set power level at maximum rate for scanning. */
514 	ieee80211_hw_config(local, 0);
515 
516 	ieee80211_queue_delayed_work(&local->hw,
517 				     &local->scan_work, 0);
518 
519 	return 0;
520 }
521 
522 static bool __ieee80211_can_leave_ch(struct ieee80211_sub_if_data *sdata)
523 {
524 	struct ieee80211_local *local = sdata->local;
525 	struct ieee80211_sub_if_data *sdata_iter;
526 
527 	if (!ieee80211_is_radar_required(local))
528 		return true;
529 
530 	if (!regulatory_pre_cac_allowed(local->hw.wiphy))
531 		return false;
532 
533 	mutex_lock(&local->iflist_mtx);
534 	list_for_each_entry(sdata_iter, &local->interfaces, list) {
535 		if (sdata_iter->wdev.cac_started) {
536 			mutex_unlock(&local->iflist_mtx);
537 			return false;
538 		}
539 	}
540 	mutex_unlock(&local->iflist_mtx);
541 
542 	return true;
543 }
544 
545 static bool ieee80211_can_scan(struct ieee80211_local *local,
546 			       struct ieee80211_sub_if_data *sdata)
547 {
548 	if (!__ieee80211_can_leave_ch(sdata))
549 		return false;
550 
551 	if (!list_empty(&local->roc_list))
552 		return false;
553 
554 	if (sdata->vif.type == NL80211_IFTYPE_STATION &&
555 	    sdata->u.mgd.flags & IEEE80211_STA_CONNECTION_POLL)
556 		return false;
557 
558 	return true;
559 }
560 
561 void ieee80211_run_deferred_scan(struct ieee80211_local *local)
562 {
563 	lockdep_assert_held(&local->mtx);
564 
565 	if (!local->scan_req || local->scanning)
566 		return;
567 
568 	if (!ieee80211_can_scan(local,
569 				rcu_dereference_protected(
570 					local->scan_sdata,
571 					lockdep_is_held(&local->mtx))))
572 		return;
573 
574 	ieee80211_queue_delayed_work(&local->hw, &local->scan_work,
575 				     round_jiffies_relative(0));
576 }
577 
578 static void ieee80211_send_scan_probe_req(struct ieee80211_sub_if_data *sdata,
579 					  const u8 *src, const u8 *dst,
580 					  const u8 *ssid, size_t ssid_len,
581 					  const u8 *ie, size_t ie_len,
582 					  u32 ratemask, u32 flags, u32 tx_flags,
583 					  struct ieee80211_channel *channel)
584 {
585 	struct sk_buff *skb;
586 	u32 txdata_flags = 0;
587 
588 	skb = ieee80211_build_probe_req(sdata, src, dst, ratemask, channel,
589 					ssid, ssid_len,
590 					ie, ie_len, flags);
591 
592 	if (skb) {
593 		if (flags & IEEE80211_PROBE_FLAG_RANDOM_SN) {
594 			struct ieee80211_hdr *hdr = (void *)skb->data;
595 			u16 sn = get_random_u32();
596 
597 			txdata_flags |= IEEE80211_TX_NO_SEQNO;
598 			hdr->seq_ctrl =
599 				cpu_to_le16(IEEE80211_SN_TO_SEQ(sn));
600 		}
601 		IEEE80211_SKB_CB(skb)->flags |= tx_flags;
602 		ieee80211_tx_skb_tid_band(sdata, skb, 7, channel->band,
603 					  txdata_flags);
604 	}
605 }
606 
607 static void ieee80211_scan_state_send_probe(struct ieee80211_local *local,
608 					    unsigned long *next_delay)
609 {
610 	int i;
611 	struct ieee80211_sub_if_data *sdata;
612 	struct cfg80211_scan_request *scan_req;
613 	enum nl80211_band band = local->hw.conf.chandef.chan->band;
614 	u32 flags = 0, tx_flags;
615 
616 	scan_req = rcu_dereference_protected(local->scan_req,
617 					     lockdep_is_held(&local->mtx));
618 
619 	tx_flags = IEEE80211_TX_INTFL_OFFCHAN_TX_OK;
620 	if (scan_req->no_cck)
621 		tx_flags |= IEEE80211_TX_CTL_NO_CCK_RATE;
622 	if (scan_req->flags & NL80211_SCAN_FLAG_MIN_PREQ_CONTENT)
623 		flags |= IEEE80211_PROBE_FLAG_MIN_CONTENT;
624 	if (scan_req->flags & NL80211_SCAN_FLAG_RANDOM_SN)
625 		flags |= IEEE80211_PROBE_FLAG_RANDOM_SN;
626 
627 	sdata = rcu_dereference_protected(local->scan_sdata,
628 					  lockdep_is_held(&local->mtx));
629 
630 	for (i = 0; i < scan_req->n_ssids; i++)
631 		ieee80211_send_scan_probe_req(
632 			sdata, local->scan_addr, scan_req->bssid,
633 			scan_req->ssids[i].ssid, scan_req->ssids[i].ssid_len,
634 			scan_req->ie, scan_req->ie_len,
635 			scan_req->rates[band], flags,
636 			tx_flags, local->hw.conf.chandef.chan);
637 
638 	/*
639 	 * After sending probe requests, wait for probe responses
640 	 * on the channel.
641 	 */
642 	*next_delay = IEEE80211_CHANNEL_TIME;
643 	local->next_scan_state = SCAN_DECISION;
644 }
645 
646 static int __ieee80211_start_scan(struct ieee80211_sub_if_data *sdata,
647 				  struct cfg80211_scan_request *req)
648 {
649 	struct ieee80211_local *local = sdata->local;
650 	bool hw_scan = local->ops->hw_scan;
651 	int rc;
652 
653 	lockdep_assert_held(&local->mtx);
654 
655 	if (local->scan_req)
656 		return -EBUSY;
657 
658 	if (!__ieee80211_can_leave_ch(sdata))
659 		return -EBUSY;
660 
661 	if (!ieee80211_can_scan(local, sdata)) {
662 		/* wait for the work to finish/time out */
663 		rcu_assign_pointer(local->scan_req, req);
664 		rcu_assign_pointer(local->scan_sdata, sdata);
665 		return 0;
666 	}
667 
668  again:
669 	if (hw_scan) {
670 		u8 *ies;
671 
672 		local->hw_scan_ies_bufsize = local->scan_ies_len + req->ie_len;
673 
674 		if (ieee80211_hw_check(&local->hw, SINGLE_SCAN_ON_ALL_BANDS)) {
675 			int i, n_bands = 0;
676 			u8 bands_counted = 0;
677 
678 			for (i = 0; i < req->n_channels; i++) {
679 				if (bands_counted & BIT(req->channels[i]->band))
680 					continue;
681 				bands_counted |= BIT(req->channels[i]->band);
682 				n_bands++;
683 			}
684 
685 			local->hw_scan_ies_bufsize *= n_bands;
686 		}
687 
688 		local->hw_scan_req = kmalloc(
689 				sizeof(*local->hw_scan_req) +
690 				req->n_channels * sizeof(req->channels[0]) +
691 				local->hw_scan_ies_bufsize, GFP_KERNEL);
692 		if (!local->hw_scan_req)
693 			return -ENOMEM;
694 
695 		local->hw_scan_req->req.ssids = req->ssids;
696 		local->hw_scan_req->req.n_ssids = req->n_ssids;
697 		ies = (u8 *)local->hw_scan_req +
698 			sizeof(*local->hw_scan_req) +
699 			req->n_channels * sizeof(req->channels[0]);
700 		local->hw_scan_req->req.ie = ies;
701 		local->hw_scan_req->req.flags = req->flags;
702 		eth_broadcast_addr(local->hw_scan_req->req.bssid);
703 		local->hw_scan_req->req.duration = req->duration;
704 		local->hw_scan_req->req.duration_mandatory =
705 			req->duration_mandatory;
706 
707 		local->hw_scan_band = 0;
708 
709 		/*
710 		 * After allocating local->hw_scan_req, we must
711 		 * go through until ieee80211_prep_hw_scan(), so
712 		 * anything that might be changed here and leave
713 		 * this function early must not go after this
714 		 * allocation.
715 		 */
716 	}
717 
718 	rcu_assign_pointer(local->scan_req, req);
719 	rcu_assign_pointer(local->scan_sdata, sdata);
720 
721 	if (req->flags & NL80211_SCAN_FLAG_RANDOM_ADDR)
722 		get_random_mask_addr(local->scan_addr,
723 				     req->mac_addr,
724 				     req->mac_addr_mask);
725 	else
726 		memcpy(local->scan_addr, sdata->vif.addr, ETH_ALEN);
727 
728 	if (hw_scan) {
729 		__set_bit(SCAN_HW_SCANNING, &local->scanning);
730 	} else if ((req->n_channels == 1) &&
731 		   (req->channels[0] == local->_oper_chandef.chan)) {
732 		/*
733 		 * If we are scanning only on the operating channel
734 		 * then we do not need to stop normal activities
735 		 */
736 		unsigned long next_delay;
737 
738 		__set_bit(SCAN_ONCHANNEL_SCANNING, &local->scanning);
739 
740 		ieee80211_recalc_idle(local);
741 
742 		/* Notify driver scan is starting, keep order of operations
743 		 * same as normal software scan, in case that matters. */
744 		drv_sw_scan_start(local, sdata, local->scan_addr);
745 
746 		ieee80211_configure_filter(local); /* accept probe-responses */
747 
748 		/* We need to ensure power level is at max for scanning. */
749 		ieee80211_hw_config(local, 0);
750 
751 		if ((req->channels[0]->flags & (IEEE80211_CHAN_NO_IR |
752 						IEEE80211_CHAN_RADAR)) ||
753 		    !req->n_ssids) {
754 			next_delay = IEEE80211_PASSIVE_CHANNEL_TIME;
755 		} else {
756 			ieee80211_scan_state_send_probe(local, &next_delay);
757 			next_delay = IEEE80211_CHANNEL_TIME;
758 		}
759 
760 		/* Now, just wait a bit and we are all done! */
761 		ieee80211_queue_delayed_work(&local->hw, &local->scan_work,
762 					     next_delay);
763 		return 0;
764 	} else {
765 		/* Do normal software scan */
766 		__set_bit(SCAN_SW_SCANNING, &local->scanning);
767 	}
768 
769 	ieee80211_recalc_idle(local);
770 
771 	if (hw_scan) {
772 		WARN_ON(!ieee80211_prep_hw_scan(local));
773 		rc = drv_hw_scan(local, sdata, local->hw_scan_req);
774 	} else {
775 		rc = ieee80211_start_sw_scan(local, sdata);
776 	}
777 
778 	if (rc) {
779 		kfree(local->hw_scan_req);
780 		local->hw_scan_req = NULL;
781 		local->scanning = 0;
782 
783 		ieee80211_recalc_idle(local);
784 
785 		local->scan_req = NULL;
786 		RCU_INIT_POINTER(local->scan_sdata, NULL);
787 	}
788 
789 	if (hw_scan && rc == 1) {
790 		/*
791 		 * we can't fall back to software for P2P-GO
792 		 * as it must update NoA etc.
793 		 */
794 		if (ieee80211_vif_type_p2p(&sdata->vif) ==
795 				NL80211_IFTYPE_P2P_GO)
796 			return -EOPNOTSUPP;
797 		hw_scan = false;
798 		goto again;
799 	}
800 
801 	return rc;
802 }
803 
804 static unsigned long
805 ieee80211_scan_get_channel_time(struct ieee80211_channel *chan)
806 {
807 	/*
808 	 * TODO: channel switching also consumes quite some time,
809 	 * add that delay as well to get a better estimation
810 	 */
811 	if (chan->flags & (IEEE80211_CHAN_NO_IR | IEEE80211_CHAN_RADAR))
812 		return IEEE80211_PASSIVE_CHANNEL_TIME;
813 	return IEEE80211_PROBE_DELAY + IEEE80211_CHANNEL_TIME;
814 }
815 
816 static void ieee80211_scan_state_decision(struct ieee80211_local *local,
817 					  unsigned long *next_delay)
818 {
819 	bool associated = false;
820 	bool tx_empty = true;
821 	bool bad_latency;
822 	struct ieee80211_sub_if_data *sdata;
823 	struct ieee80211_channel *next_chan;
824 	enum mac80211_scan_state next_scan_state;
825 	struct cfg80211_scan_request *scan_req;
826 
827 	/*
828 	 * check if at least one STA interface is associated,
829 	 * check if at least one STA interface has pending tx frames
830 	 * and grab the lowest used beacon interval
831 	 */
832 	mutex_lock(&local->iflist_mtx);
833 	list_for_each_entry(sdata, &local->interfaces, list) {
834 		if (!ieee80211_sdata_running(sdata))
835 			continue;
836 
837 		if (sdata->vif.type == NL80211_IFTYPE_STATION) {
838 			if (sdata->u.mgd.associated) {
839 				associated = true;
840 
841 				if (!qdisc_all_tx_empty(sdata->dev)) {
842 					tx_empty = false;
843 					break;
844 				}
845 			}
846 		}
847 	}
848 	mutex_unlock(&local->iflist_mtx);
849 
850 	scan_req = rcu_dereference_protected(local->scan_req,
851 					     lockdep_is_held(&local->mtx));
852 
853 	next_chan = scan_req->channels[local->scan_channel_idx];
854 
855 	/*
856 	 * we're currently scanning a different channel, let's
857 	 * see if we can scan another channel without interfering
858 	 * with the current traffic situation.
859 	 *
860 	 * Keep good latency, do not stay off-channel more than 125 ms.
861 	 */
862 
863 	bad_latency = time_after(jiffies +
864 				 ieee80211_scan_get_channel_time(next_chan),
865 				 local->leave_oper_channel_time + HZ / 8);
866 
867 	if (associated && !tx_empty) {
868 		if (scan_req->flags & NL80211_SCAN_FLAG_LOW_PRIORITY)
869 			next_scan_state = SCAN_ABORT;
870 		else
871 			next_scan_state = SCAN_SUSPEND;
872 	} else if (associated && bad_latency) {
873 		next_scan_state = SCAN_SUSPEND;
874 	} else {
875 		next_scan_state = SCAN_SET_CHANNEL;
876 	}
877 
878 	local->next_scan_state = next_scan_state;
879 
880 	*next_delay = 0;
881 }
882 
883 static void ieee80211_scan_state_set_channel(struct ieee80211_local *local,
884 					     unsigned long *next_delay)
885 {
886 	int skip;
887 	struct ieee80211_channel *chan;
888 	enum nl80211_bss_scan_width oper_scan_width;
889 	struct cfg80211_scan_request *scan_req;
890 
891 	scan_req = rcu_dereference_protected(local->scan_req,
892 					     lockdep_is_held(&local->mtx));
893 
894 	skip = 0;
895 	chan = scan_req->channels[local->scan_channel_idx];
896 
897 	local->scan_chandef.chan = chan;
898 	local->scan_chandef.center_freq1 = chan->center_freq;
899 	local->scan_chandef.center_freq2 = 0;
900 	switch (scan_req->scan_width) {
901 	case NL80211_BSS_CHAN_WIDTH_5:
902 		local->scan_chandef.width = NL80211_CHAN_WIDTH_5;
903 		break;
904 	case NL80211_BSS_CHAN_WIDTH_10:
905 		local->scan_chandef.width = NL80211_CHAN_WIDTH_10;
906 		break;
907 	case NL80211_BSS_CHAN_WIDTH_20:
908 		/* If scanning on oper channel, use whatever channel-type
909 		 * is currently in use.
910 		 */
911 		oper_scan_width = cfg80211_chandef_to_scan_width(
912 					&local->_oper_chandef);
913 		if (chan == local->_oper_chandef.chan &&
914 		    oper_scan_width == scan_req->scan_width)
915 			local->scan_chandef = local->_oper_chandef;
916 		else
917 			local->scan_chandef.width = NL80211_CHAN_WIDTH_20_NOHT;
918 		break;
919 	}
920 
921 	if (ieee80211_hw_config(local, IEEE80211_CONF_CHANGE_CHANNEL))
922 		skip = 1;
923 
924 	/* advance state machine to next channel/band */
925 	local->scan_channel_idx++;
926 
927 	if (skip) {
928 		/* if we skip this channel return to the decision state */
929 		local->next_scan_state = SCAN_DECISION;
930 		return;
931 	}
932 
933 	/*
934 	 * Probe delay is used to update the NAV, cf. 11.1.3.2.2
935 	 * (which unfortunately doesn't say _why_ step a) is done,
936 	 * but it waits for the probe delay or until a frame is
937 	 * received - and the received frame would update the NAV).
938 	 * For now, we do not support waiting until a frame is
939 	 * received.
940 	 *
941 	 * In any case, it is not necessary for a passive scan.
942 	 */
943 	if ((chan->flags & (IEEE80211_CHAN_NO_IR | IEEE80211_CHAN_RADAR)) ||
944 	    !scan_req->n_ssids) {
945 		*next_delay = IEEE80211_PASSIVE_CHANNEL_TIME;
946 		local->next_scan_state = SCAN_DECISION;
947 		return;
948 	}
949 
950 	/* active scan, send probes */
951 	*next_delay = IEEE80211_PROBE_DELAY;
952 	local->next_scan_state = SCAN_SEND_PROBE;
953 }
954 
955 static void ieee80211_scan_state_suspend(struct ieee80211_local *local,
956 					 unsigned long *next_delay)
957 {
958 	/* switch back to the operating channel */
959 	local->scan_chandef.chan = NULL;
960 	ieee80211_hw_config(local, IEEE80211_CONF_CHANGE_CHANNEL);
961 
962 	/* disable PS */
963 	ieee80211_offchannel_return(local);
964 
965 	*next_delay = HZ / 5;
966 	/* afterwards, resume scan & go to next channel */
967 	local->next_scan_state = SCAN_RESUME;
968 }
969 
970 static void ieee80211_scan_state_resume(struct ieee80211_local *local,
971 					unsigned long *next_delay)
972 {
973 	ieee80211_offchannel_stop_vifs(local);
974 
975 	if (local->ops->flush) {
976 		ieee80211_flush_queues(local, NULL, false);
977 		*next_delay = 0;
978 	} else
979 		*next_delay = HZ / 10;
980 
981 	/* remember when we left the operating channel */
982 	local->leave_oper_channel_time = jiffies;
983 
984 	/* advance to the next channel to be scanned */
985 	local->next_scan_state = SCAN_SET_CHANNEL;
986 }
987 
988 void ieee80211_scan_work(struct work_struct *work)
989 {
990 	struct ieee80211_local *local =
991 		container_of(work, struct ieee80211_local, scan_work.work);
992 	struct ieee80211_sub_if_data *sdata;
993 	struct cfg80211_scan_request *scan_req;
994 	unsigned long next_delay = 0;
995 	bool aborted;
996 
997 	mutex_lock(&local->mtx);
998 
999 	if (!ieee80211_can_run_worker(local)) {
1000 		aborted = true;
1001 		goto out_complete;
1002 	}
1003 
1004 	sdata = rcu_dereference_protected(local->scan_sdata,
1005 					  lockdep_is_held(&local->mtx));
1006 	scan_req = rcu_dereference_protected(local->scan_req,
1007 					     lockdep_is_held(&local->mtx));
1008 
1009 	/* When scanning on-channel, the first-callback means completed. */
1010 	if (test_bit(SCAN_ONCHANNEL_SCANNING, &local->scanning)) {
1011 		aborted = test_and_clear_bit(SCAN_ABORTED, &local->scanning);
1012 		goto out_complete;
1013 	}
1014 
1015 	if (test_and_clear_bit(SCAN_COMPLETED, &local->scanning)) {
1016 		aborted = test_and_clear_bit(SCAN_ABORTED, &local->scanning);
1017 		goto out_complete;
1018 	}
1019 
1020 	if (!sdata || !scan_req)
1021 		goto out;
1022 
1023 	if (!local->scanning) {
1024 		int rc;
1025 
1026 		RCU_INIT_POINTER(local->scan_req, NULL);
1027 		RCU_INIT_POINTER(local->scan_sdata, NULL);
1028 
1029 		rc = __ieee80211_start_scan(sdata, scan_req);
1030 		if (rc) {
1031 			/* need to complete scan in cfg80211 */
1032 			rcu_assign_pointer(local->scan_req, scan_req);
1033 			aborted = true;
1034 			goto out_complete;
1035 		} else
1036 			goto out;
1037 	}
1038 
1039 	/*
1040 	 * as long as no delay is required advance immediately
1041 	 * without scheduling a new work
1042 	 */
1043 	do {
1044 		if (!ieee80211_sdata_running(sdata)) {
1045 			aborted = true;
1046 			goto out_complete;
1047 		}
1048 
1049 		switch (local->next_scan_state) {
1050 		case SCAN_DECISION:
1051 			/* if no more bands/channels left, complete scan */
1052 			if (local->scan_channel_idx >= scan_req->n_channels) {
1053 				aborted = false;
1054 				goto out_complete;
1055 			}
1056 			ieee80211_scan_state_decision(local, &next_delay);
1057 			break;
1058 		case SCAN_SET_CHANNEL:
1059 			ieee80211_scan_state_set_channel(local, &next_delay);
1060 			break;
1061 		case SCAN_SEND_PROBE:
1062 			ieee80211_scan_state_send_probe(local, &next_delay);
1063 			break;
1064 		case SCAN_SUSPEND:
1065 			ieee80211_scan_state_suspend(local, &next_delay);
1066 			break;
1067 		case SCAN_RESUME:
1068 			ieee80211_scan_state_resume(local, &next_delay);
1069 			break;
1070 		case SCAN_ABORT:
1071 			aborted = true;
1072 			goto out_complete;
1073 		}
1074 	} while (next_delay == 0);
1075 
1076 	ieee80211_queue_delayed_work(&local->hw, &local->scan_work, next_delay);
1077 	goto out;
1078 
1079 out_complete:
1080 	__ieee80211_scan_completed(&local->hw, aborted);
1081 out:
1082 	mutex_unlock(&local->mtx);
1083 }
1084 
1085 int ieee80211_request_scan(struct ieee80211_sub_if_data *sdata,
1086 			   struct cfg80211_scan_request *req)
1087 {
1088 	int res;
1089 
1090 	mutex_lock(&sdata->local->mtx);
1091 	res = __ieee80211_start_scan(sdata, req);
1092 	mutex_unlock(&sdata->local->mtx);
1093 
1094 	return res;
1095 }
1096 
1097 int ieee80211_request_ibss_scan(struct ieee80211_sub_if_data *sdata,
1098 				const u8 *ssid, u8 ssid_len,
1099 				struct ieee80211_channel **channels,
1100 				unsigned int n_channels,
1101 				enum nl80211_bss_scan_width scan_width)
1102 {
1103 	struct ieee80211_local *local = sdata->local;
1104 	int ret = -EBUSY, i, n_ch = 0;
1105 	enum nl80211_band band;
1106 
1107 	mutex_lock(&local->mtx);
1108 
1109 	/* busy scanning */
1110 	if (local->scan_req)
1111 		goto unlock;
1112 
1113 	/* fill internal scan request */
1114 	if (!channels) {
1115 		int max_n;
1116 
1117 		for (band = 0; band < NUM_NL80211_BANDS; band++) {
1118 			if (!local->hw.wiphy->bands[band])
1119 				continue;
1120 
1121 			max_n = local->hw.wiphy->bands[band]->n_channels;
1122 			for (i = 0; i < max_n; i++) {
1123 				struct ieee80211_channel *tmp_ch =
1124 				    &local->hw.wiphy->bands[band]->channels[i];
1125 
1126 				if (tmp_ch->flags & (IEEE80211_CHAN_NO_IR |
1127 						     IEEE80211_CHAN_DISABLED))
1128 					continue;
1129 
1130 				local->int_scan_req->channels[n_ch] = tmp_ch;
1131 				n_ch++;
1132 			}
1133 		}
1134 
1135 		if (WARN_ON_ONCE(n_ch == 0))
1136 			goto unlock;
1137 
1138 		local->int_scan_req->n_channels = n_ch;
1139 	} else {
1140 		for (i = 0; i < n_channels; i++) {
1141 			if (channels[i]->flags & (IEEE80211_CHAN_NO_IR |
1142 						  IEEE80211_CHAN_DISABLED))
1143 				continue;
1144 
1145 			local->int_scan_req->channels[n_ch] = channels[i];
1146 			n_ch++;
1147 		}
1148 
1149 		if (WARN_ON_ONCE(n_ch == 0))
1150 			goto unlock;
1151 
1152 		local->int_scan_req->n_channels = n_ch;
1153 	}
1154 
1155 	local->int_scan_req->ssids = &local->scan_ssid;
1156 	local->int_scan_req->n_ssids = 1;
1157 	local->int_scan_req->scan_width = scan_width;
1158 	memcpy(local->int_scan_req->ssids[0].ssid, ssid, IEEE80211_MAX_SSID_LEN);
1159 	local->int_scan_req->ssids[0].ssid_len = ssid_len;
1160 
1161 	ret = __ieee80211_start_scan(sdata, sdata->local->int_scan_req);
1162  unlock:
1163 	mutex_unlock(&local->mtx);
1164 	return ret;
1165 }
1166 
1167 /*
1168  * Only call this function when a scan can't be queued -- under RTNL.
1169  */
1170 void ieee80211_scan_cancel(struct ieee80211_local *local)
1171 {
1172 	/*
1173 	 * We are canceling software scan, or deferred scan that was not
1174 	 * yet really started (see __ieee80211_start_scan ).
1175 	 *
1176 	 * Regarding hardware scan:
1177 	 * - we can not call  __ieee80211_scan_completed() as when
1178 	 *   SCAN_HW_SCANNING bit is set this function change
1179 	 *   local->hw_scan_req to operate on 5G band, what race with
1180 	 *   driver which can use local->hw_scan_req
1181 	 *
1182 	 * - we can not cancel scan_work since driver can schedule it
1183 	 *   by ieee80211_scan_completed(..., true) to finish scan
1184 	 *
1185 	 * Hence we only call the cancel_hw_scan() callback, but the low-level
1186 	 * driver is still responsible for calling ieee80211_scan_completed()
1187 	 * after the scan was completed/aborted.
1188 	 */
1189 
1190 	mutex_lock(&local->mtx);
1191 	if (!local->scan_req)
1192 		goto out;
1193 
1194 	/*
1195 	 * We have a scan running and the driver already reported completion,
1196 	 * but the worker hasn't run yet or is stuck on the mutex - mark it as
1197 	 * cancelled.
1198 	 */
1199 	if (test_bit(SCAN_HW_SCANNING, &local->scanning) &&
1200 	    test_bit(SCAN_COMPLETED, &local->scanning)) {
1201 		set_bit(SCAN_HW_CANCELLED, &local->scanning);
1202 		goto out;
1203 	}
1204 
1205 	if (test_bit(SCAN_HW_SCANNING, &local->scanning)) {
1206 		/*
1207 		 * Make sure that __ieee80211_scan_completed doesn't trigger a
1208 		 * scan on another band.
1209 		 */
1210 		set_bit(SCAN_HW_CANCELLED, &local->scanning);
1211 		if (local->ops->cancel_hw_scan)
1212 			drv_cancel_hw_scan(local,
1213 				rcu_dereference_protected(local->scan_sdata,
1214 						lockdep_is_held(&local->mtx)));
1215 		goto out;
1216 	}
1217 
1218 	/*
1219 	 * If the work is currently running, it must be blocked on
1220 	 * the mutex, but we'll set scan_sdata = NULL and it'll
1221 	 * simply exit once it acquires the mutex.
1222 	 */
1223 	cancel_delayed_work(&local->scan_work);
1224 	/* and clean up */
1225 	memset(&local->scan_info, 0, sizeof(local->scan_info));
1226 	__ieee80211_scan_completed(&local->hw, true);
1227 out:
1228 	mutex_unlock(&local->mtx);
1229 }
1230 
1231 int __ieee80211_request_sched_scan_start(struct ieee80211_sub_if_data *sdata,
1232 					struct cfg80211_sched_scan_request *req)
1233 {
1234 	struct ieee80211_local *local = sdata->local;
1235 	struct ieee80211_scan_ies sched_scan_ies = {};
1236 	struct cfg80211_chan_def chandef;
1237 	int ret, i, iebufsz, num_bands = 0;
1238 	u32 rate_masks[NUM_NL80211_BANDS] = {};
1239 	u8 bands_used = 0;
1240 	u8 *ie;
1241 	u32 flags = 0;
1242 
1243 	iebufsz = local->scan_ies_len + req->ie_len;
1244 
1245 	lockdep_assert_held(&local->mtx);
1246 
1247 	if (!local->ops->sched_scan_start)
1248 		return -ENOTSUPP;
1249 
1250 	for (i = 0; i < NUM_NL80211_BANDS; i++) {
1251 		if (local->hw.wiphy->bands[i]) {
1252 			bands_used |= BIT(i);
1253 			rate_masks[i] = (u32) -1;
1254 			num_bands++;
1255 		}
1256 	}
1257 
1258 	if (req->flags & NL80211_SCAN_FLAG_MIN_PREQ_CONTENT)
1259 		flags |= IEEE80211_PROBE_FLAG_MIN_CONTENT;
1260 
1261 	ie = kcalloc(iebufsz, num_bands, GFP_KERNEL);
1262 	if (!ie) {
1263 		ret = -ENOMEM;
1264 		goto out;
1265 	}
1266 
1267 	ieee80211_prepare_scan_chandef(&chandef, req->scan_width);
1268 
1269 	ieee80211_build_preq_ies(local, ie, num_bands * iebufsz,
1270 				 &sched_scan_ies, req->ie,
1271 				 req->ie_len, bands_used, rate_masks, &chandef,
1272 				 flags);
1273 
1274 	ret = drv_sched_scan_start(local, sdata, req, &sched_scan_ies);
1275 	if (ret == 0) {
1276 		rcu_assign_pointer(local->sched_scan_sdata, sdata);
1277 		rcu_assign_pointer(local->sched_scan_req, req);
1278 	}
1279 
1280 	kfree(ie);
1281 
1282 out:
1283 	if (ret) {
1284 		/* Clean in case of failure after HW restart or upon resume. */
1285 		RCU_INIT_POINTER(local->sched_scan_sdata, NULL);
1286 		RCU_INIT_POINTER(local->sched_scan_req, NULL);
1287 	}
1288 
1289 	return ret;
1290 }
1291 
1292 int ieee80211_request_sched_scan_start(struct ieee80211_sub_if_data *sdata,
1293 				       struct cfg80211_sched_scan_request *req)
1294 {
1295 	struct ieee80211_local *local = sdata->local;
1296 	int ret;
1297 
1298 	mutex_lock(&local->mtx);
1299 
1300 	if (rcu_access_pointer(local->sched_scan_sdata)) {
1301 		mutex_unlock(&local->mtx);
1302 		return -EBUSY;
1303 	}
1304 
1305 	ret = __ieee80211_request_sched_scan_start(sdata, req);
1306 
1307 	mutex_unlock(&local->mtx);
1308 	return ret;
1309 }
1310 
1311 int ieee80211_request_sched_scan_stop(struct ieee80211_local *local)
1312 {
1313 	struct ieee80211_sub_if_data *sched_scan_sdata;
1314 	int ret = -ENOENT;
1315 
1316 	mutex_lock(&local->mtx);
1317 
1318 	if (!local->ops->sched_scan_stop) {
1319 		ret = -ENOTSUPP;
1320 		goto out;
1321 	}
1322 
1323 	/* We don't want to restart sched scan anymore. */
1324 	RCU_INIT_POINTER(local->sched_scan_req, NULL);
1325 
1326 	sched_scan_sdata = rcu_dereference_protected(local->sched_scan_sdata,
1327 						lockdep_is_held(&local->mtx));
1328 	if (sched_scan_sdata) {
1329 		ret = drv_sched_scan_stop(local, sched_scan_sdata);
1330 		if (!ret)
1331 			RCU_INIT_POINTER(local->sched_scan_sdata, NULL);
1332 	}
1333 out:
1334 	mutex_unlock(&local->mtx);
1335 
1336 	return ret;
1337 }
1338 
1339 void ieee80211_sched_scan_results(struct ieee80211_hw *hw)
1340 {
1341 	struct ieee80211_local *local = hw_to_local(hw);
1342 
1343 	trace_api_sched_scan_results(local);
1344 
1345 	cfg80211_sched_scan_results(hw->wiphy, 0);
1346 }
1347 EXPORT_SYMBOL(ieee80211_sched_scan_results);
1348 
1349 void ieee80211_sched_scan_end(struct ieee80211_local *local)
1350 {
1351 	mutex_lock(&local->mtx);
1352 
1353 	if (!rcu_access_pointer(local->sched_scan_sdata)) {
1354 		mutex_unlock(&local->mtx);
1355 		return;
1356 	}
1357 
1358 	RCU_INIT_POINTER(local->sched_scan_sdata, NULL);
1359 
1360 	/* If sched scan was aborted by the driver. */
1361 	RCU_INIT_POINTER(local->sched_scan_req, NULL);
1362 
1363 	mutex_unlock(&local->mtx);
1364 
1365 	cfg80211_sched_scan_stopped(local->hw.wiphy, 0);
1366 }
1367 
1368 void ieee80211_sched_scan_stopped_work(struct work_struct *work)
1369 {
1370 	struct ieee80211_local *local =
1371 		container_of(work, struct ieee80211_local,
1372 			     sched_scan_stopped_work);
1373 
1374 	ieee80211_sched_scan_end(local);
1375 }
1376 
1377 void ieee80211_sched_scan_stopped(struct ieee80211_hw *hw)
1378 {
1379 	struct ieee80211_local *local = hw_to_local(hw);
1380 
1381 	trace_api_sched_scan_stopped(local);
1382 
1383 	/*
1384 	 * this shouldn't really happen, so for simplicity
1385 	 * simply ignore it, and let mac80211 reconfigure
1386 	 * the sched scan later on.
1387 	 */
1388 	if (local->in_reconfig)
1389 		return;
1390 
1391 	schedule_work(&local->sched_scan_stopped_work);
1392 }
1393 EXPORT_SYMBOL(ieee80211_sched_scan_stopped);
1394