xref: /openbmc/linux/net/mac80211/scan.c (revision aeb64ff3)
1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3  * Scanning implementation
4  *
5  * Copyright 2003, Jouni Malinen <jkmaline@cc.hut.fi>
6  * Copyright 2004, Instant802 Networks, Inc.
7  * Copyright 2005, Devicescape Software, Inc.
8  * Copyright 2006-2007	Jiri Benc <jbenc@suse.cz>
9  * Copyright 2007, Michael Wu <flamingice@sourmilk.net>
10  * Copyright 2013-2015  Intel Mobile Communications GmbH
11  * Copyright 2016-2017  Intel Deutschland GmbH
12  * Copyright (C) 2018-2019 Intel Corporation
13  */
14 
15 #include <linux/if_arp.h>
16 #include <linux/etherdevice.h>
17 #include <linux/rtnetlink.h>
18 #include <net/sch_generic.h>
19 #include <linux/slab.h>
20 #include <linux/export.h>
21 #include <linux/random.h>
22 #include <net/mac80211.h>
23 
24 #include "ieee80211_i.h"
25 #include "driver-ops.h"
26 #include "mesh.h"
27 
28 #define IEEE80211_PROBE_DELAY (HZ / 33)
29 #define IEEE80211_CHANNEL_TIME (HZ / 33)
30 #define IEEE80211_PASSIVE_CHANNEL_TIME (HZ / 9)
31 
32 void ieee80211_rx_bss_put(struct ieee80211_local *local,
33 			  struct ieee80211_bss *bss)
34 {
35 	if (!bss)
36 		return;
37 	cfg80211_put_bss(local->hw.wiphy,
38 			 container_of((void *)bss, struct cfg80211_bss, priv));
39 }
40 
41 static bool is_uapsd_supported(struct ieee802_11_elems *elems)
42 {
43 	u8 qos_info;
44 
45 	if (elems->wmm_info && elems->wmm_info_len == 7
46 	    && elems->wmm_info[5] == 1)
47 		qos_info = elems->wmm_info[6];
48 	else if (elems->wmm_param && elems->wmm_param_len == 24
49 		 && elems->wmm_param[5] == 1)
50 		qos_info = elems->wmm_param[6];
51 	else
52 		/* no valid wmm information or parameter element found */
53 		return false;
54 
55 	return qos_info & IEEE80211_WMM_IE_AP_QOSINFO_UAPSD;
56 }
57 
58 static void
59 ieee80211_update_bss_from_elems(struct ieee80211_local *local,
60 				struct ieee80211_bss *bss,
61 				struct ieee802_11_elems *elems,
62 				struct ieee80211_rx_status *rx_status,
63 				bool beacon)
64 {
65 	int clen, srlen;
66 
67 	if (beacon)
68 		bss->device_ts_beacon = rx_status->device_timestamp;
69 	else
70 		bss->device_ts_presp = rx_status->device_timestamp;
71 
72 	if (elems->parse_error) {
73 		if (beacon)
74 			bss->corrupt_data |= IEEE80211_BSS_CORRUPT_BEACON;
75 		else
76 			bss->corrupt_data |= IEEE80211_BSS_CORRUPT_PROBE_RESP;
77 	} else {
78 		if (beacon)
79 			bss->corrupt_data &= ~IEEE80211_BSS_CORRUPT_BEACON;
80 		else
81 			bss->corrupt_data &= ~IEEE80211_BSS_CORRUPT_PROBE_RESP;
82 	}
83 
84 	/* save the ERP value so that it is available at association time */
85 	if (elems->erp_info && (!elems->parse_error ||
86 				!(bss->valid_data & IEEE80211_BSS_VALID_ERP))) {
87 		bss->erp_value = elems->erp_info[0];
88 		bss->has_erp_value = true;
89 		if (!elems->parse_error)
90 			bss->valid_data |= IEEE80211_BSS_VALID_ERP;
91 	}
92 
93 	/* replace old supported rates if we get new values */
94 	if (!elems->parse_error ||
95 	    !(bss->valid_data & IEEE80211_BSS_VALID_RATES)) {
96 		srlen = 0;
97 		if (elems->supp_rates) {
98 			clen = IEEE80211_MAX_SUPP_RATES;
99 			if (clen > elems->supp_rates_len)
100 				clen = elems->supp_rates_len;
101 			memcpy(bss->supp_rates, elems->supp_rates, clen);
102 			srlen += clen;
103 		}
104 		if (elems->ext_supp_rates) {
105 			clen = IEEE80211_MAX_SUPP_RATES - srlen;
106 			if (clen > elems->ext_supp_rates_len)
107 				clen = elems->ext_supp_rates_len;
108 			memcpy(bss->supp_rates + srlen, elems->ext_supp_rates,
109 			       clen);
110 			srlen += clen;
111 		}
112 		if (srlen) {
113 			bss->supp_rates_len = srlen;
114 			if (!elems->parse_error)
115 				bss->valid_data |= IEEE80211_BSS_VALID_RATES;
116 		}
117 	}
118 
119 	if (!elems->parse_error ||
120 	    !(bss->valid_data & IEEE80211_BSS_VALID_WMM)) {
121 		bss->wmm_used = elems->wmm_param || elems->wmm_info;
122 		bss->uapsd_supported = is_uapsd_supported(elems);
123 		if (!elems->parse_error)
124 			bss->valid_data |= IEEE80211_BSS_VALID_WMM;
125 	}
126 
127 	if (beacon) {
128 		struct ieee80211_supported_band *sband =
129 			local->hw.wiphy->bands[rx_status->band];
130 		if (!(rx_status->encoding == RX_ENC_HT) &&
131 		    !(rx_status->encoding == RX_ENC_VHT))
132 			bss->beacon_rate =
133 				&sband->bitrates[rx_status->rate_idx];
134 	}
135 }
136 
137 struct ieee80211_bss *
138 ieee80211_bss_info_update(struct ieee80211_local *local,
139 			  struct ieee80211_rx_status *rx_status,
140 			  struct ieee80211_mgmt *mgmt, size_t len,
141 			  struct ieee80211_channel *channel)
142 {
143 	bool beacon = ieee80211_is_beacon(mgmt->frame_control);
144 	struct cfg80211_bss *cbss, *non_tx_cbss;
145 	struct ieee80211_bss *bss, *non_tx_bss;
146 	struct cfg80211_inform_bss bss_meta = {
147 		.boottime_ns = rx_status->boottime_ns,
148 	};
149 	bool signal_valid;
150 	struct ieee80211_sub_if_data *scan_sdata;
151 	struct ieee802_11_elems elems;
152 	size_t baselen;
153 	u8 *elements;
154 
155 	if (rx_status->flag & RX_FLAG_NO_SIGNAL_VAL)
156 		bss_meta.signal = 0; /* invalid signal indication */
157 	else if (ieee80211_hw_check(&local->hw, SIGNAL_DBM))
158 		bss_meta.signal = rx_status->signal * 100;
159 	else if (ieee80211_hw_check(&local->hw, SIGNAL_UNSPEC))
160 		bss_meta.signal = (rx_status->signal * 100) / local->hw.max_signal;
161 
162 	bss_meta.scan_width = NL80211_BSS_CHAN_WIDTH_20;
163 	if (rx_status->bw == RATE_INFO_BW_5)
164 		bss_meta.scan_width = NL80211_BSS_CHAN_WIDTH_5;
165 	else if (rx_status->bw == RATE_INFO_BW_10)
166 		bss_meta.scan_width = NL80211_BSS_CHAN_WIDTH_10;
167 
168 	bss_meta.chan = channel;
169 
170 	rcu_read_lock();
171 	scan_sdata = rcu_dereference(local->scan_sdata);
172 	if (scan_sdata && scan_sdata->vif.type == NL80211_IFTYPE_STATION &&
173 	    scan_sdata->vif.bss_conf.assoc &&
174 	    ieee80211_have_rx_timestamp(rx_status)) {
175 		bss_meta.parent_tsf =
176 			ieee80211_calculate_rx_timestamp(local, rx_status,
177 							 len + FCS_LEN, 24);
178 		ether_addr_copy(bss_meta.parent_bssid,
179 				scan_sdata->vif.bss_conf.bssid);
180 	}
181 	rcu_read_unlock();
182 
183 	cbss = cfg80211_inform_bss_frame_data(local->hw.wiphy, &bss_meta,
184 					      mgmt, len, GFP_ATOMIC);
185 	if (!cbss)
186 		return NULL;
187 
188 	if (ieee80211_is_probe_resp(mgmt->frame_control)) {
189 		elements = mgmt->u.probe_resp.variable;
190 		baselen = offsetof(struct ieee80211_mgmt,
191 				   u.probe_resp.variable);
192 	} else {
193 		baselen = offsetof(struct ieee80211_mgmt, u.beacon.variable);
194 		elements = mgmt->u.beacon.variable;
195 	}
196 
197 	if (baselen > len)
198 		return NULL;
199 
200 	ieee802_11_parse_elems(elements, len - baselen, false, &elems,
201 			       mgmt->bssid, cbss->bssid);
202 
203 	/* In case the signal is invalid update the status */
204 	signal_valid = abs(channel->center_freq - cbss->channel->center_freq)
205 		<= local->hw.wiphy->max_adj_channel_rssi_comp;
206 	if (!signal_valid)
207 		rx_status->flag |= RX_FLAG_NO_SIGNAL_VAL;
208 
209 	bss = (void *)cbss->priv;
210 	ieee80211_update_bss_from_elems(local, bss, &elems, rx_status, beacon);
211 
212 	list_for_each_entry(non_tx_cbss, &cbss->nontrans_list, nontrans_list) {
213 		non_tx_bss = (void *)non_tx_cbss->priv;
214 
215 		ieee80211_update_bss_from_elems(local, non_tx_bss, &elems,
216 						rx_status, beacon);
217 	}
218 
219 	return bss;
220 }
221 
222 static bool ieee80211_scan_accept_presp(struct ieee80211_sub_if_data *sdata,
223 					u32 scan_flags, const u8 *da)
224 {
225 	if (!sdata)
226 		return false;
227 	/* accept broadcast for OCE */
228 	if (scan_flags & NL80211_SCAN_FLAG_ACCEPT_BCAST_PROBE_RESP &&
229 	    is_broadcast_ether_addr(da))
230 		return true;
231 	if (scan_flags & NL80211_SCAN_FLAG_RANDOM_ADDR)
232 		return true;
233 	return ether_addr_equal(da, sdata->vif.addr);
234 }
235 
236 void ieee80211_scan_rx(struct ieee80211_local *local, struct sk_buff *skb)
237 {
238 	struct ieee80211_rx_status *rx_status = IEEE80211_SKB_RXCB(skb);
239 	struct ieee80211_sub_if_data *sdata1, *sdata2;
240 	struct ieee80211_mgmt *mgmt = (void *)skb->data;
241 	struct ieee80211_bss *bss;
242 	struct ieee80211_channel *channel;
243 
244 	if (skb->len < 24 ||
245 	    (!ieee80211_is_probe_resp(mgmt->frame_control) &&
246 	     !ieee80211_is_beacon(mgmt->frame_control)))
247 		return;
248 
249 	sdata1 = rcu_dereference(local->scan_sdata);
250 	sdata2 = rcu_dereference(local->sched_scan_sdata);
251 
252 	if (likely(!sdata1 && !sdata2))
253 		return;
254 
255 	if (ieee80211_is_probe_resp(mgmt->frame_control)) {
256 		struct cfg80211_scan_request *scan_req;
257 		struct cfg80211_sched_scan_request *sched_scan_req;
258 		u32 scan_req_flags = 0, sched_scan_req_flags = 0;
259 
260 		scan_req = rcu_dereference(local->scan_req);
261 		sched_scan_req = rcu_dereference(local->sched_scan_req);
262 
263 		if (scan_req)
264 			scan_req_flags = scan_req->flags;
265 
266 		if (sched_scan_req)
267 			sched_scan_req_flags = sched_scan_req->flags;
268 
269 		/* ignore ProbeResp to foreign address or non-bcast (OCE)
270 		 * unless scanning with randomised address
271 		 */
272 		if (!ieee80211_scan_accept_presp(sdata1, scan_req_flags,
273 						 mgmt->da) &&
274 		    !ieee80211_scan_accept_presp(sdata2, sched_scan_req_flags,
275 						 mgmt->da))
276 			return;
277 	}
278 
279 	channel = ieee80211_get_channel(local->hw.wiphy, rx_status->freq);
280 
281 	if (!channel || channel->flags & IEEE80211_CHAN_DISABLED)
282 		return;
283 
284 	bss = ieee80211_bss_info_update(local, rx_status,
285 					mgmt, skb->len,
286 					channel);
287 	if (bss)
288 		ieee80211_rx_bss_put(local, bss);
289 }
290 
291 static void
292 ieee80211_prepare_scan_chandef(struct cfg80211_chan_def *chandef,
293 			       enum nl80211_bss_scan_width scan_width)
294 {
295 	memset(chandef, 0, sizeof(*chandef));
296 	switch (scan_width) {
297 	case NL80211_BSS_CHAN_WIDTH_5:
298 		chandef->width = NL80211_CHAN_WIDTH_5;
299 		break;
300 	case NL80211_BSS_CHAN_WIDTH_10:
301 		chandef->width = NL80211_CHAN_WIDTH_10;
302 		break;
303 	default:
304 		chandef->width = NL80211_CHAN_WIDTH_20_NOHT;
305 		break;
306 	}
307 }
308 
309 /* return false if no more work */
310 static bool ieee80211_prep_hw_scan(struct ieee80211_local *local)
311 {
312 	struct cfg80211_scan_request *req;
313 	struct cfg80211_chan_def chandef;
314 	u8 bands_used = 0;
315 	int i, ielen, n_chans;
316 	u32 flags = 0;
317 
318 	req = rcu_dereference_protected(local->scan_req,
319 					lockdep_is_held(&local->mtx));
320 
321 	if (test_bit(SCAN_HW_CANCELLED, &local->scanning))
322 		return false;
323 
324 	if (ieee80211_hw_check(&local->hw, SINGLE_SCAN_ON_ALL_BANDS)) {
325 		for (i = 0; i < req->n_channels; i++) {
326 			local->hw_scan_req->req.channels[i] = req->channels[i];
327 			bands_used |= BIT(req->channels[i]->band);
328 		}
329 
330 		n_chans = req->n_channels;
331 	} else {
332 		do {
333 			if (local->hw_scan_band == NUM_NL80211_BANDS)
334 				return false;
335 
336 			n_chans = 0;
337 
338 			for (i = 0; i < req->n_channels; i++) {
339 				if (req->channels[i]->band !=
340 				    local->hw_scan_band)
341 					continue;
342 				local->hw_scan_req->req.channels[n_chans] =
343 							req->channels[i];
344 				n_chans++;
345 				bands_used |= BIT(req->channels[i]->band);
346 			}
347 
348 			local->hw_scan_band++;
349 		} while (!n_chans);
350 	}
351 
352 	local->hw_scan_req->req.n_channels = n_chans;
353 	ieee80211_prepare_scan_chandef(&chandef, req->scan_width);
354 
355 	if (req->flags & NL80211_SCAN_FLAG_MIN_PREQ_CONTENT)
356 		flags |= IEEE80211_PROBE_FLAG_MIN_CONTENT;
357 
358 	ielen = ieee80211_build_preq_ies(local,
359 					 (u8 *)local->hw_scan_req->req.ie,
360 					 local->hw_scan_ies_bufsize,
361 					 &local->hw_scan_req->ies,
362 					 req->ie, req->ie_len,
363 					 bands_used, req->rates, &chandef,
364 					 flags);
365 	local->hw_scan_req->req.ie_len = ielen;
366 	local->hw_scan_req->req.no_cck = req->no_cck;
367 	ether_addr_copy(local->hw_scan_req->req.mac_addr, req->mac_addr);
368 	ether_addr_copy(local->hw_scan_req->req.mac_addr_mask,
369 			req->mac_addr_mask);
370 	ether_addr_copy(local->hw_scan_req->req.bssid, req->bssid);
371 
372 	return true;
373 }
374 
375 static void __ieee80211_scan_completed(struct ieee80211_hw *hw, bool aborted)
376 {
377 	struct ieee80211_local *local = hw_to_local(hw);
378 	bool hw_scan = test_bit(SCAN_HW_SCANNING, &local->scanning);
379 	bool was_scanning = local->scanning;
380 	struct cfg80211_scan_request *scan_req;
381 	struct ieee80211_sub_if_data *scan_sdata;
382 	struct ieee80211_sub_if_data *sdata;
383 
384 	lockdep_assert_held(&local->mtx);
385 
386 	/*
387 	 * It's ok to abort a not-yet-running scan (that
388 	 * we have one at all will be verified by checking
389 	 * local->scan_req next), but not to complete it
390 	 * successfully.
391 	 */
392 	if (WARN_ON(!local->scanning && !aborted))
393 		aborted = true;
394 
395 	if (WARN_ON(!local->scan_req))
396 		return;
397 
398 	if (hw_scan && !aborted &&
399 	    !ieee80211_hw_check(&local->hw, SINGLE_SCAN_ON_ALL_BANDS) &&
400 	    ieee80211_prep_hw_scan(local)) {
401 		int rc;
402 
403 		rc = drv_hw_scan(local,
404 			rcu_dereference_protected(local->scan_sdata,
405 						  lockdep_is_held(&local->mtx)),
406 			local->hw_scan_req);
407 
408 		if (rc == 0)
409 			return;
410 
411 		/* HW scan failed and is going to be reported as aborted,
412 		 * so clear old scan info.
413 		 */
414 		memset(&local->scan_info, 0, sizeof(local->scan_info));
415 		aborted = true;
416 	}
417 
418 	kfree(local->hw_scan_req);
419 	local->hw_scan_req = NULL;
420 
421 	scan_req = rcu_dereference_protected(local->scan_req,
422 					     lockdep_is_held(&local->mtx));
423 
424 	if (scan_req != local->int_scan_req) {
425 		local->scan_info.aborted = aborted;
426 		cfg80211_scan_done(scan_req, &local->scan_info);
427 	}
428 	RCU_INIT_POINTER(local->scan_req, NULL);
429 
430 	scan_sdata = rcu_dereference_protected(local->scan_sdata,
431 					       lockdep_is_held(&local->mtx));
432 	RCU_INIT_POINTER(local->scan_sdata, NULL);
433 
434 	local->scanning = 0;
435 	local->scan_chandef.chan = NULL;
436 
437 	/* Set power back to normal operating levels. */
438 	ieee80211_hw_config(local, 0);
439 
440 	if (!hw_scan) {
441 		ieee80211_configure_filter(local);
442 		drv_sw_scan_complete(local, scan_sdata);
443 		ieee80211_offchannel_return(local);
444 	}
445 
446 	ieee80211_recalc_idle(local);
447 
448 	ieee80211_mlme_notify_scan_completed(local);
449 	ieee80211_ibss_notify_scan_completed(local);
450 
451 	/* Requeue all the work that might have been ignored while
452 	 * the scan was in progress; if there was none this will
453 	 * just be a no-op for the particular interface.
454 	 */
455 	list_for_each_entry_rcu(sdata, &local->interfaces, list) {
456 		if (ieee80211_sdata_running(sdata))
457 			ieee80211_queue_work(&sdata->local->hw, &sdata->work);
458 	}
459 
460 	if (was_scanning)
461 		ieee80211_start_next_roc(local);
462 }
463 
464 void ieee80211_scan_completed(struct ieee80211_hw *hw,
465 			      struct cfg80211_scan_info *info)
466 {
467 	struct ieee80211_local *local = hw_to_local(hw);
468 
469 	trace_api_scan_completed(local, info->aborted);
470 
471 	set_bit(SCAN_COMPLETED, &local->scanning);
472 	if (info->aborted)
473 		set_bit(SCAN_ABORTED, &local->scanning);
474 
475 	memcpy(&local->scan_info, info, sizeof(*info));
476 
477 	ieee80211_queue_delayed_work(&local->hw, &local->scan_work, 0);
478 }
479 EXPORT_SYMBOL(ieee80211_scan_completed);
480 
481 static int ieee80211_start_sw_scan(struct ieee80211_local *local,
482 				   struct ieee80211_sub_if_data *sdata)
483 {
484 	/* Software scan is not supported in multi-channel cases */
485 	if (local->use_chanctx)
486 		return -EOPNOTSUPP;
487 
488 	/*
489 	 * Hardware/driver doesn't support hw_scan, so use software
490 	 * scanning instead. First send a nullfunc frame with power save
491 	 * bit on so that AP will buffer the frames for us while we are not
492 	 * listening, then send probe requests to each channel and wait for
493 	 * the responses. After all channels are scanned, tune back to the
494 	 * original channel and send a nullfunc frame with power save bit
495 	 * off to trigger the AP to send us all the buffered frames.
496 	 *
497 	 * Note that while local->sw_scanning is true everything else but
498 	 * nullfunc frames and probe requests will be dropped in
499 	 * ieee80211_tx_h_check_assoc().
500 	 */
501 	drv_sw_scan_start(local, sdata, local->scan_addr);
502 
503 	local->leave_oper_channel_time = jiffies;
504 	local->next_scan_state = SCAN_DECISION;
505 	local->scan_channel_idx = 0;
506 
507 	ieee80211_offchannel_stop_vifs(local);
508 
509 	/* ensure nullfunc is transmitted before leaving operating channel */
510 	ieee80211_flush_queues(local, NULL, false);
511 
512 	ieee80211_configure_filter(local);
513 
514 	/* We need to set power level at maximum rate for scanning. */
515 	ieee80211_hw_config(local, 0);
516 
517 	ieee80211_queue_delayed_work(&local->hw,
518 				     &local->scan_work, 0);
519 
520 	return 0;
521 }
522 
523 static bool __ieee80211_can_leave_ch(struct ieee80211_sub_if_data *sdata)
524 {
525 	struct ieee80211_local *local = sdata->local;
526 	struct ieee80211_sub_if_data *sdata_iter;
527 
528 	if (!ieee80211_is_radar_required(local))
529 		return true;
530 
531 	if (!regulatory_pre_cac_allowed(local->hw.wiphy))
532 		return false;
533 
534 	mutex_lock(&local->iflist_mtx);
535 	list_for_each_entry(sdata_iter, &local->interfaces, list) {
536 		if (sdata_iter->wdev.cac_started) {
537 			mutex_unlock(&local->iflist_mtx);
538 			return false;
539 		}
540 	}
541 	mutex_unlock(&local->iflist_mtx);
542 
543 	return true;
544 }
545 
546 static bool ieee80211_can_scan(struct ieee80211_local *local,
547 			       struct ieee80211_sub_if_data *sdata)
548 {
549 	if (!__ieee80211_can_leave_ch(sdata))
550 		return false;
551 
552 	if (!list_empty(&local->roc_list))
553 		return false;
554 
555 	if (sdata->vif.type == NL80211_IFTYPE_STATION &&
556 	    sdata->u.mgd.flags & IEEE80211_STA_CONNECTION_POLL)
557 		return false;
558 
559 	return true;
560 }
561 
562 void ieee80211_run_deferred_scan(struct ieee80211_local *local)
563 {
564 	lockdep_assert_held(&local->mtx);
565 
566 	if (!local->scan_req || local->scanning)
567 		return;
568 
569 	if (!ieee80211_can_scan(local,
570 				rcu_dereference_protected(
571 					local->scan_sdata,
572 					lockdep_is_held(&local->mtx))))
573 		return;
574 
575 	ieee80211_queue_delayed_work(&local->hw, &local->scan_work,
576 				     round_jiffies_relative(0));
577 }
578 
579 static void ieee80211_send_scan_probe_req(struct ieee80211_sub_if_data *sdata,
580 					  const u8 *src, const u8 *dst,
581 					  const u8 *ssid, size_t ssid_len,
582 					  const u8 *ie, size_t ie_len,
583 					  u32 ratemask, u32 flags, u32 tx_flags,
584 					  struct ieee80211_channel *channel)
585 {
586 	struct sk_buff *skb;
587 	u32 txdata_flags = 0;
588 
589 	skb = ieee80211_build_probe_req(sdata, src, dst, ratemask, channel,
590 					ssid, ssid_len,
591 					ie, ie_len, flags);
592 
593 	if (skb) {
594 		if (flags & IEEE80211_PROBE_FLAG_RANDOM_SN) {
595 			struct ieee80211_hdr *hdr = (void *)skb->data;
596 			u16 sn = get_random_u32();
597 
598 			txdata_flags |= IEEE80211_TX_NO_SEQNO;
599 			hdr->seq_ctrl =
600 				cpu_to_le16(IEEE80211_SN_TO_SEQ(sn));
601 		}
602 		IEEE80211_SKB_CB(skb)->flags |= tx_flags;
603 		ieee80211_tx_skb_tid_band(sdata, skb, 7, channel->band,
604 					  txdata_flags);
605 	}
606 }
607 
608 static void ieee80211_scan_state_send_probe(struct ieee80211_local *local,
609 					    unsigned long *next_delay)
610 {
611 	int i;
612 	struct ieee80211_sub_if_data *sdata;
613 	struct cfg80211_scan_request *scan_req;
614 	enum nl80211_band band = local->hw.conf.chandef.chan->band;
615 	u32 flags = 0, tx_flags;
616 
617 	scan_req = rcu_dereference_protected(local->scan_req,
618 					     lockdep_is_held(&local->mtx));
619 
620 	tx_flags = IEEE80211_TX_INTFL_OFFCHAN_TX_OK;
621 	if (scan_req->no_cck)
622 		tx_flags |= IEEE80211_TX_CTL_NO_CCK_RATE;
623 	if (scan_req->flags & NL80211_SCAN_FLAG_MIN_PREQ_CONTENT)
624 		flags |= IEEE80211_PROBE_FLAG_MIN_CONTENT;
625 	if (scan_req->flags & NL80211_SCAN_FLAG_RANDOM_SN)
626 		flags |= IEEE80211_PROBE_FLAG_RANDOM_SN;
627 
628 	sdata = rcu_dereference_protected(local->scan_sdata,
629 					  lockdep_is_held(&local->mtx));
630 
631 	for (i = 0; i < scan_req->n_ssids; i++)
632 		ieee80211_send_scan_probe_req(
633 			sdata, local->scan_addr, scan_req->bssid,
634 			scan_req->ssids[i].ssid, scan_req->ssids[i].ssid_len,
635 			scan_req->ie, scan_req->ie_len,
636 			scan_req->rates[band], flags,
637 			tx_flags, local->hw.conf.chandef.chan);
638 
639 	/*
640 	 * After sending probe requests, wait for probe responses
641 	 * on the channel.
642 	 */
643 	*next_delay = IEEE80211_CHANNEL_TIME;
644 	local->next_scan_state = SCAN_DECISION;
645 }
646 
647 static int __ieee80211_start_scan(struct ieee80211_sub_if_data *sdata,
648 				  struct cfg80211_scan_request *req)
649 {
650 	struct ieee80211_local *local = sdata->local;
651 	bool hw_scan = local->ops->hw_scan;
652 	int rc;
653 
654 	lockdep_assert_held(&local->mtx);
655 
656 	if (local->scan_req)
657 		return -EBUSY;
658 
659 	if (!__ieee80211_can_leave_ch(sdata))
660 		return -EBUSY;
661 
662 	if (!ieee80211_can_scan(local, sdata)) {
663 		/* wait for the work to finish/time out */
664 		rcu_assign_pointer(local->scan_req, req);
665 		rcu_assign_pointer(local->scan_sdata, sdata);
666 		return 0;
667 	}
668 
669  again:
670 	if (hw_scan) {
671 		u8 *ies;
672 
673 		local->hw_scan_ies_bufsize = local->scan_ies_len + req->ie_len;
674 
675 		if (ieee80211_hw_check(&local->hw, SINGLE_SCAN_ON_ALL_BANDS)) {
676 			int i, n_bands = 0;
677 			u8 bands_counted = 0;
678 
679 			for (i = 0; i < req->n_channels; i++) {
680 				if (bands_counted & BIT(req->channels[i]->band))
681 					continue;
682 				bands_counted |= BIT(req->channels[i]->band);
683 				n_bands++;
684 			}
685 
686 			local->hw_scan_ies_bufsize *= n_bands;
687 		}
688 
689 		local->hw_scan_req = kmalloc(
690 				sizeof(*local->hw_scan_req) +
691 				req->n_channels * sizeof(req->channels[0]) +
692 				local->hw_scan_ies_bufsize, GFP_KERNEL);
693 		if (!local->hw_scan_req)
694 			return -ENOMEM;
695 
696 		local->hw_scan_req->req.ssids = req->ssids;
697 		local->hw_scan_req->req.n_ssids = req->n_ssids;
698 		ies = (u8 *)local->hw_scan_req +
699 			sizeof(*local->hw_scan_req) +
700 			req->n_channels * sizeof(req->channels[0]);
701 		local->hw_scan_req->req.ie = ies;
702 		local->hw_scan_req->req.flags = req->flags;
703 		eth_broadcast_addr(local->hw_scan_req->req.bssid);
704 		local->hw_scan_req->req.duration = req->duration;
705 		local->hw_scan_req->req.duration_mandatory =
706 			req->duration_mandatory;
707 
708 		local->hw_scan_band = 0;
709 
710 		/*
711 		 * After allocating local->hw_scan_req, we must
712 		 * go through until ieee80211_prep_hw_scan(), so
713 		 * anything that might be changed here and leave
714 		 * this function early must not go after this
715 		 * allocation.
716 		 */
717 	}
718 
719 	rcu_assign_pointer(local->scan_req, req);
720 	rcu_assign_pointer(local->scan_sdata, sdata);
721 
722 	if (req->flags & NL80211_SCAN_FLAG_RANDOM_ADDR)
723 		get_random_mask_addr(local->scan_addr,
724 				     req->mac_addr,
725 				     req->mac_addr_mask);
726 	else
727 		memcpy(local->scan_addr, sdata->vif.addr, ETH_ALEN);
728 
729 	if (hw_scan) {
730 		__set_bit(SCAN_HW_SCANNING, &local->scanning);
731 	} else if ((req->n_channels == 1) &&
732 		   (req->channels[0] == local->_oper_chandef.chan)) {
733 		/*
734 		 * If we are scanning only on the operating channel
735 		 * then we do not need to stop normal activities
736 		 */
737 		unsigned long next_delay;
738 
739 		__set_bit(SCAN_ONCHANNEL_SCANNING, &local->scanning);
740 
741 		ieee80211_recalc_idle(local);
742 
743 		/* Notify driver scan is starting, keep order of operations
744 		 * same as normal software scan, in case that matters. */
745 		drv_sw_scan_start(local, sdata, local->scan_addr);
746 
747 		ieee80211_configure_filter(local); /* accept probe-responses */
748 
749 		/* We need to ensure power level is at max for scanning. */
750 		ieee80211_hw_config(local, 0);
751 
752 		if ((req->channels[0]->flags & (IEEE80211_CHAN_NO_IR |
753 						IEEE80211_CHAN_RADAR)) ||
754 		    !req->n_ssids) {
755 			next_delay = IEEE80211_PASSIVE_CHANNEL_TIME;
756 		} else {
757 			ieee80211_scan_state_send_probe(local, &next_delay);
758 			next_delay = IEEE80211_CHANNEL_TIME;
759 		}
760 
761 		/* Now, just wait a bit and we are all done! */
762 		ieee80211_queue_delayed_work(&local->hw, &local->scan_work,
763 					     next_delay);
764 		return 0;
765 	} else {
766 		/* Do normal software scan */
767 		__set_bit(SCAN_SW_SCANNING, &local->scanning);
768 	}
769 
770 	ieee80211_recalc_idle(local);
771 
772 	if (hw_scan) {
773 		WARN_ON(!ieee80211_prep_hw_scan(local));
774 		rc = drv_hw_scan(local, sdata, local->hw_scan_req);
775 	} else {
776 		rc = ieee80211_start_sw_scan(local, sdata);
777 	}
778 
779 	if (rc) {
780 		kfree(local->hw_scan_req);
781 		local->hw_scan_req = NULL;
782 		local->scanning = 0;
783 
784 		ieee80211_recalc_idle(local);
785 
786 		local->scan_req = NULL;
787 		RCU_INIT_POINTER(local->scan_sdata, NULL);
788 	}
789 
790 	if (hw_scan && rc == 1) {
791 		/*
792 		 * we can't fall back to software for P2P-GO
793 		 * as it must update NoA etc.
794 		 */
795 		if (ieee80211_vif_type_p2p(&sdata->vif) ==
796 				NL80211_IFTYPE_P2P_GO)
797 			return -EOPNOTSUPP;
798 		hw_scan = false;
799 		goto again;
800 	}
801 
802 	return rc;
803 }
804 
805 static unsigned long
806 ieee80211_scan_get_channel_time(struct ieee80211_channel *chan)
807 {
808 	/*
809 	 * TODO: channel switching also consumes quite some time,
810 	 * add that delay as well to get a better estimation
811 	 */
812 	if (chan->flags & (IEEE80211_CHAN_NO_IR | IEEE80211_CHAN_RADAR))
813 		return IEEE80211_PASSIVE_CHANNEL_TIME;
814 	return IEEE80211_PROBE_DELAY + IEEE80211_CHANNEL_TIME;
815 }
816 
817 static void ieee80211_scan_state_decision(struct ieee80211_local *local,
818 					  unsigned long *next_delay)
819 {
820 	bool associated = false;
821 	bool tx_empty = true;
822 	bool bad_latency;
823 	struct ieee80211_sub_if_data *sdata;
824 	struct ieee80211_channel *next_chan;
825 	enum mac80211_scan_state next_scan_state;
826 	struct cfg80211_scan_request *scan_req;
827 
828 	/*
829 	 * check if at least one STA interface is associated,
830 	 * check if at least one STA interface has pending tx frames
831 	 * and grab the lowest used beacon interval
832 	 */
833 	mutex_lock(&local->iflist_mtx);
834 	list_for_each_entry(sdata, &local->interfaces, list) {
835 		if (!ieee80211_sdata_running(sdata))
836 			continue;
837 
838 		if (sdata->vif.type == NL80211_IFTYPE_STATION) {
839 			if (sdata->u.mgd.associated) {
840 				associated = true;
841 
842 				if (!qdisc_all_tx_empty(sdata->dev)) {
843 					tx_empty = false;
844 					break;
845 				}
846 			}
847 		}
848 	}
849 	mutex_unlock(&local->iflist_mtx);
850 
851 	scan_req = rcu_dereference_protected(local->scan_req,
852 					     lockdep_is_held(&local->mtx));
853 
854 	next_chan = scan_req->channels[local->scan_channel_idx];
855 
856 	/*
857 	 * we're currently scanning a different channel, let's
858 	 * see if we can scan another channel without interfering
859 	 * with the current traffic situation.
860 	 *
861 	 * Keep good latency, do not stay off-channel more than 125 ms.
862 	 */
863 
864 	bad_latency = time_after(jiffies +
865 				 ieee80211_scan_get_channel_time(next_chan),
866 				 local->leave_oper_channel_time + HZ / 8);
867 
868 	if (associated && !tx_empty) {
869 		if (scan_req->flags & NL80211_SCAN_FLAG_LOW_PRIORITY)
870 			next_scan_state = SCAN_ABORT;
871 		else
872 			next_scan_state = SCAN_SUSPEND;
873 	} else if (associated && bad_latency) {
874 		next_scan_state = SCAN_SUSPEND;
875 	} else {
876 		next_scan_state = SCAN_SET_CHANNEL;
877 	}
878 
879 	local->next_scan_state = next_scan_state;
880 
881 	*next_delay = 0;
882 }
883 
884 static void ieee80211_scan_state_set_channel(struct ieee80211_local *local,
885 					     unsigned long *next_delay)
886 {
887 	int skip;
888 	struct ieee80211_channel *chan;
889 	enum nl80211_bss_scan_width oper_scan_width;
890 	struct cfg80211_scan_request *scan_req;
891 
892 	scan_req = rcu_dereference_protected(local->scan_req,
893 					     lockdep_is_held(&local->mtx));
894 
895 	skip = 0;
896 	chan = scan_req->channels[local->scan_channel_idx];
897 
898 	local->scan_chandef.chan = chan;
899 	local->scan_chandef.center_freq1 = chan->center_freq;
900 	local->scan_chandef.center_freq2 = 0;
901 	switch (scan_req->scan_width) {
902 	case NL80211_BSS_CHAN_WIDTH_5:
903 		local->scan_chandef.width = NL80211_CHAN_WIDTH_5;
904 		break;
905 	case NL80211_BSS_CHAN_WIDTH_10:
906 		local->scan_chandef.width = NL80211_CHAN_WIDTH_10;
907 		break;
908 	case NL80211_BSS_CHAN_WIDTH_20:
909 		/* If scanning on oper channel, use whatever channel-type
910 		 * is currently in use.
911 		 */
912 		oper_scan_width = cfg80211_chandef_to_scan_width(
913 					&local->_oper_chandef);
914 		if (chan == local->_oper_chandef.chan &&
915 		    oper_scan_width == scan_req->scan_width)
916 			local->scan_chandef = local->_oper_chandef;
917 		else
918 			local->scan_chandef.width = NL80211_CHAN_WIDTH_20_NOHT;
919 		break;
920 	}
921 
922 	if (ieee80211_hw_config(local, IEEE80211_CONF_CHANGE_CHANNEL))
923 		skip = 1;
924 
925 	/* advance state machine to next channel/band */
926 	local->scan_channel_idx++;
927 
928 	if (skip) {
929 		/* if we skip this channel return to the decision state */
930 		local->next_scan_state = SCAN_DECISION;
931 		return;
932 	}
933 
934 	/*
935 	 * Probe delay is used to update the NAV, cf. 11.1.3.2.2
936 	 * (which unfortunately doesn't say _why_ step a) is done,
937 	 * but it waits for the probe delay or until a frame is
938 	 * received - and the received frame would update the NAV).
939 	 * For now, we do not support waiting until a frame is
940 	 * received.
941 	 *
942 	 * In any case, it is not necessary for a passive scan.
943 	 */
944 	if ((chan->flags & (IEEE80211_CHAN_NO_IR | IEEE80211_CHAN_RADAR)) ||
945 	    !scan_req->n_ssids) {
946 		*next_delay = IEEE80211_PASSIVE_CHANNEL_TIME;
947 		local->next_scan_state = SCAN_DECISION;
948 		return;
949 	}
950 
951 	/* active scan, send probes */
952 	*next_delay = IEEE80211_PROBE_DELAY;
953 	local->next_scan_state = SCAN_SEND_PROBE;
954 }
955 
956 static void ieee80211_scan_state_suspend(struct ieee80211_local *local,
957 					 unsigned long *next_delay)
958 {
959 	/* switch back to the operating channel */
960 	local->scan_chandef.chan = NULL;
961 	ieee80211_hw_config(local, IEEE80211_CONF_CHANGE_CHANNEL);
962 
963 	/* disable PS */
964 	ieee80211_offchannel_return(local);
965 
966 	*next_delay = HZ / 5;
967 	/* afterwards, resume scan & go to next channel */
968 	local->next_scan_state = SCAN_RESUME;
969 }
970 
971 static void ieee80211_scan_state_resume(struct ieee80211_local *local,
972 					unsigned long *next_delay)
973 {
974 	ieee80211_offchannel_stop_vifs(local);
975 
976 	if (local->ops->flush) {
977 		ieee80211_flush_queues(local, NULL, false);
978 		*next_delay = 0;
979 	} else
980 		*next_delay = HZ / 10;
981 
982 	/* remember when we left the operating channel */
983 	local->leave_oper_channel_time = jiffies;
984 
985 	/* advance to the next channel to be scanned */
986 	local->next_scan_state = SCAN_SET_CHANNEL;
987 }
988 
989 void ieee80211_scan_work(struct work_struct *work)
990 {
991 	struct ieee80211_local *local =
992 		container_of(work, struct ieee80211_local, scan_work.work);
993 	struct ieee80211_sub_if_data *sdata;
994 	struct cfg80211_scan_request *scan_req;
995 	unsigned long next_delay = 0;
996 	bool aborted;
997 
998 	mutex_lock(&local->mtx);
999 
1000 	if (!ieee80211_can_run_worker(local)) {
1001 		aborted = true;
1002 		goto out_complete;
1003 	}
1004 
1005 	sdata = rcu_dereference_protected(local->scan_sdata,
1006 					  lockdep_is_held(&local->mtx));
1007 	scan_req = rcu_dereference_protected(local->scan_req,
1008 					     lockdep_is_held(&local->mtx));
1009 
1010 	/* When scanning on-channel, the first-callback means completed. */
1011 	if (test_bit(SCAN_ONCHANNEL_SCANNING, &local->scanning)) {
1012 		aborted = test_and_clear_bit(SCAN_ABORTED, &local->scanning);
1013 		goto out_complete;
1014 	}
1015 
1016 	if (test_and_clear_bit(SCAN_COMPLETED, &local->scanning)) {
1017 		aborted = test_and_clear_bit(SCAN_ABORTED, &local->scanning);
1018 		goto out_complete;
1019 	}
1020 
1021 	if (!sdata || !scan_req)
1022 		goto out;
1023 
1024 	if (!local->scanning) {
1025 		int rc;
1026 
1027 		RCU_INIT_POINTER(local->scan_req, NULL);
1028 		RCU_INIT_POINTER(local->scan_sdata, NULL);
1029 
1030 		rc = __ieee80211_start_scan(sdata, scan_req);
1031 		if (rc) {
1032 			/* need to complete scan in cfg80211 */
1033 			rcu_assign_pointer(local->scan_req, scan_req);
1034 			aborted = true;
1035 			goto out_complete;
1036 		} else
1037 			goto out;
1038 	}
1039 
1040 	/*
1041 	 * as long as no delay is required advance immediately
1042 	 * without scheduling a new work
1043 	 */
1044 	do {
1045 		if (!ieee80211_sdata_running(sdata)) {
1046 			aborted = true;
1047 			goto out_complete;
1048 		}
1049 
1050 		switch (local->next_scan_state) {
1051 		case SCAN_DECISION:
1052 			/* if no more bands/channels left, complete scan */
1053 			if (local->scan_channel_idx >= scan_req->n_channels) {
1054 				aborted = false;
1055 				goto out_complete;
1056 			}
1057 			ieee80211_scan_state_decision(local, &next_delay);
1058 			break;
1059 		case SCAN_SET_CHANNEL:
1060 			ieee80211_scan_state_set_channel(local, &next_delay);
1061 			break;
1062 		case SCAN_SEND_PROBE:
1063 			ieee80211_scan_state_send_probe(local, &next_delay);
1064 			break;
1065 		case SCAN_SUSPEND:
1066 			ieee80211_scan_state_suspend(local, &next_delay);
1067 			break;
1068 		case SCAN_RESUME:
1069 			ieee80211_scan_state_resume(local, &next_delay);
1070 			break;
1071 		case SCAN_ABORT:
1072 			aborted = true;
1073 			goto out_complete;
1074 		}
1075 	} while (next_delay == 0);
1076 
1077 	ieee80211_queue_delayed_work(&local->hw, &local->scan_work, next_delay);
1078 	goto out;
1079 
1080 out_complete:
1081 	__ieee80211_scan_completed(&local->hw, aborted);
1082 out:
1083 	mutex_unlock(&local->mtx);
1084 }
1085 
1086 int ieee80211_request_scan(struct ieee80211_sub_if_data *sdata,
1087 			   struct cfg80211_scan_request *req)
1088 {
1089 	int res;
1090 
1091 	mutex_lock(&sdata->local->mtx);
1092 	res = __ieee80211_start_scan(sdata, req);
1093 	mutex_unlock(&sdata->local->mtx);
1094 
1095 	return res;
1096 }
1097 
1098 int ieee80211_request_ibss_scan(struct ieee80211_sub_if_data *sdata,
1099 				const u8 *ssid, u8 ssid_len,
1100 				struct ieee80211_channel **channels,
1101 				unsigned int n_channels,
1102 				enum nl80211_bss_scan_width scan_width)
1103 {
1104 	struct ieee80211_local *local = sdata->local;
1105 	int ret = -EBUSY, i, n_ch = 0;
1106 	enum nl80211_band band;
1107 
1108 	mutex_lock(&local->mtx);
1109 
1110 	/* busy scanning */
1111 	if (local->scan_req)
1112 		goto unlock;
1113 
1114 	/* fill internal scan request */
1115 	if (!channels) {
1116 		int max_n;
1117 
1118 		for (band = 0; band < NUM_NL80211_BANDS; band++) {
1119 			if (!local->hw.wiphy->bands[band])
1120 				continue;
1121 
1122 			max_n = local->hw.wiphy->bands[band]->n_channels;
1123 			for (i = 0; i < max_n; i++) {
1124 				struct ieee80211_channel *tmp_ch =
1125 				    &local->hw.wiphy->bands[band]->channels[i];
1126 
1127 				if (tmp_ch->flags & (IEEE80211_CHAN_NO_IR |
1128 						     IEEE80211_CHAN_DISABLED))
1129 					continue;
1130 
1131 				local->int_scan_req->channels[n_ch] = tmp_ch;
1132 				n_ch++;
1133 			}
1134 		}
1135 
1136 		if (WARN_ON_ONCE(n_ch == 0))
1137 			goto unlock;
1138 
1139 		local->int_scan_req->n_channels = n_ch;
1140 	} else {
1141 		for (i = 0; i < n_channels; i++) {
1142 			if (channels[i]->flags & (IEEE80211_CHAN_NO_IR |
1143 						  IEEE80211_CHAN_DISABLED))
1144 				continue;
1145 
1146 			local->int_scan_req->channels[n_ch] = channels[i];
1147 			n_ch++;
1148 		}
1149 
1150 		if (WARN_ON_ONCE(n_ch == 0))
1151 			goto unlock;
1152 
1153 		local->int_scan_req->n_channels = n_ch;
1154 	}
1155 
1156 	local->int_scan_req->ssids = &local->scan_ssid;
1157 	local->int_scan_req->n_ssids = 1;
1158 	local->int_scan_req->scan_width = scan_width;
1159 	memcpy(local->int_scan_req->ssids[0].ssid, ssid, IEEE80211_MAX_SSID_LEN);
1160 	local->int_scan_req->ssids[0].ssid_len = ssid_len;
1161 
1162 	ret = __ieee80211_start_scan(sdata, sdata->local->int_scan_req);
1163  unlock:
1164 	mutex_unlock(&local->mtx);
1165 	return ret;
1166 }
1167 
1168 /*
1169  * Only call this function when a scan can't be queued -- under RTNL.
1170  */
1171 void ieee80211_scan_cancel(struct ieee80211_local *local)
1172 {
1173 	/*
1174 	 * We are canceling software scan, or deferred scan that was not
1175 	 * yet really started (see __ieee80211_start_scan ).
1176 	 *
1177 	 * Regarding hardware scan:
1178 	 * - we can not call  __ieee80211_scan_completed() as when
1179 	 *   SCAN_HW_SCANNING bit is set this function change
1180 	 *   local->hw_scan_req to operate on 5G band, what race with
1181 	 *   driver which can use local->hw_scan_req
1182 	 *
1183 	 * - we can not cancel scan_work since driver can schedule it
1184 	 *   by ieee80211_scan_completed(..., true) to finish scan
1185 	 *
1186 	 * Hence we only call the cancel_hw_scan() callback, but the low-level
1187 	 * driver is still responsible for calling ieee80211_scan_completed()
1188 	 * after the scan was completed/aborted.
1189 	 */
1190 
1191 	mutex_lock(&local->mtx);
1192 	if (!local->scan_req)
1193 		goto out;
1194 
1195 	/*
1196 	 * We have a scan running and the driver already reported completion,
1197 	 * but the worker hasn't run yet or is stuck on the mutex - mark it as
1198 	 * cancelled.
1199 	 */
1200 	if (test_bit(SCAN_HW_SCANNING, &local->scanning) &&
1201 	    test_bit(SCAN_COMPLETED, &local->scanning)) {
1202 		set_bit(SCAN_HW_CANCELLED, &local->scanning);
1203 		goto out;
1204 	}
1205 
1206 	if (test_bit(SCAN_HW_SCANNING, &local->scanning)) {
1207 		/*
1208 		 * Make sure that __ieee80211_scan_completed doesn't trigger a
1209 		 * scan on another band.
1210 		 */
1211 		set_bit(SCAN_HW_CANCELLED, &local->scanning);
1212 		if (local->ops->cancel_hw_scan)
1213 			drv_cancel_hw_scan(local,
1214 				rcu_dereference_protected(local->scan_sdata,
1215 						lockdep_is_held(&local->mtx)));
1216 		goto out;
1217 	}
1218 
1219 	/*
1220 	 * If the work is currently running, it must be blocked on
1221 	 * the mutex, but we'll set scan_sdata = NULL and it'll
1222 	 * simply exit once it acquires the mutex.
1223 	 */
1224 	cancel_delayed_work(&local->scan_work);
1225 	/* and clean up */
1226 	memset(&local->scan_info, 0, sizeof(local->scan_info));
1227 	__ieee80211_scan_completed(&local->hw, true);
1228 out:
1229 	mutex_unlock(&local->mtx);
1230 }
1231 
1232 int __ieee80211_request_sched_scan_start(struct ieee80211_sub_if_data *sdata,
1233 					struct cfg80211_sched_scan_request *req)
1234 {
1235 	struct ieee80211_local *local = sdata->local;
1236 	struct ieee80211_scan_ies sched_scan_ies = {};
1237 	struct cfg80211_chan_def chandef;
1238 	int ret, i, iebufsz, num_bands = 0;
1239 	u32 rate_masks[NUM_NL80211_BANDS] = {};
1240 	u8 bands_used = 0;
1241 	u8 *ie;
1242 	u32 flags = 0;
1243 
1244 	iebufsz = local->scan_ies_len + req->ie_len;
1245 
1246 	lockdep_assert_held(&local->mtx);
1247 
1248 	if (!local->ops->sched_scan_start)
1249 		return -ENOTSUPP;
1250 
1251 	for (i = 0; i < NUM_NL80211_BANDS; i++) {
1252 		if (local->hw.wiphy->bands[i]) {
1253 			bands_used |= BIT(i);
1254 			rate_masks[i] = (u32) -1;
1255 			num_bands++;
1256 		}
1257 	}
1258 
1259 	if (req->flags & NL80211_SCAN_FLAG_MIN_PREQ_CONTENT)
1260 		flags |= IEEE80211_PROBE_FLAG_MIN_CONTENT;
1261 
1262 	ie = kcalloc(iebufsz, num_bands, GFP_KERNEL);
1263 	if (!ie) {
1264 		ret = -ENOMEM;
1265 		goto out;
1266 	}
1267 
1268 	ieee80211_prepare_scan_chandef(&chandef, req->scan_width);
1269 
1270 	ieee80211_build_preq_ies(local, ie, num_bands * iebufsz,
1271 				 &sched_scan_ies, req->ie,
1272 				 req->ie_len, bands_used, rate_masks, &chandef,
1273 				 flags);
1274 
1275 	ret = drv_sched_scan_start(local, sdata, req, &sched_scan_ies);
1276 	if (ret == 0) {
1277 		rcu_assign_pointer(local->sched_scan_sdata, sdata);
1278 		rcu_assign_pointer(local->sched_scan_req, req);
1279 	}
1280 
1281 	kfree(ie);
1282 
1283 out:
1284 	if (ret) {
1285 		/* Clean in case of failure after HW restart or upon resume. */
1286 		RCU_INIT_POINTER(local->sched_scan_sdata, NULL);
1287 		RCU_INIT_POINTER(local->sched_scan_req, NULL);
1288 	}
1289 
1290 	return ret;
1291 }
1292 
1293 int ieee80211_request_sched_scan_start(struct ieee80211_sub_if_data *sdata,
1294 				       struct cfg80211_sched_scan_request *req)
1295 {
1296 	struct ieee80211_local *local = sdata->local;
1297 	int ret;
1298 
1299 	mutex_lock(&local->mtx);
1300 
1301 	if (rcu_access_pointer(local->sched_scan_sdata)) {
1302 		mutex_unlock(&local->mtx);
1303 		return -EBUSY;
1304 	}
1305 
1306 	ret = __ieee80211_request_sched_scan_start(sdata, req);
1307 
1308 	mutex_unlock(&local->mtx);
1309 	return ret;
1310 }
1311 
1312 int ieee80211_request_sched_scan_stop(struct ieee80211_local *local)
1313 {
1314 	struct ieee80211_sub_if_data *sched_scan_sdata;
1315 	int ret = -ENOENT;
1316 
1317 	mutex_lock(&local->mtx);
1318 
1319 	if (!local->ops->sched_scan_stop) {
1320 		ret = -ENOTSUPP;
1321 		goto out;
1322 	}
1323 
1324 	/* We don't want to restart sched scan anymore. */
1325 	RCU_INIT_POINTER(local->sched_scan_req, NULL);
1326 
1327 	sched_scan_sdata = rcu_dereference_protected(local->sched_scan_sdata,
1328 						lockdep_is_held(&local->mtx));
1329 	if (sched_scan_sdata) {
1330 		ret = drv_sched_scan_stop(local, sched_scan_sdata);
1331 		if (!ret)
1332 			RCU_INIT_POINTER(local->sched_scan_sdata, NULL);
1333 	}
1334 out:
1335 	mutex_unlock(&local->mtx);
1336 
1337 	return ret;
1338 }
1339 
1340 void ieee80211_sched_scan_results(struct ieee80211_hw *hw)
1341 {
1342 	struct ieee80211_local *local = hw_to_local(hw);
1343 
1344 	trace_api_sched_scan_results(local);
1345 
1346 	cfg80211_sched_scan_results(hw->wiphy, 0);
1347 }
1348 EXPORT_SYMBOL(ieee80211_sched_scan_results);
1349 
1350 void ieee80211_sched_scan_end(struct ieee80211_local *local)
1351 {
1352 	mutex_lock(&local->mtx);
1353 
1354 	if (!rcu_access_pointer(local->sched_scan_sdata)) {
1355 		mutex_unlock(&local->mtx);
1356 		return;
1357 	}
1358 
1359 	RCU_INIT_POINTER(local->sched_scan_sdata, NULL);
1360 
1361 	/* If sched scan was aborted by the driver. */
1362 	RCU_INIT_POINTER(local->sched_scan_req, NULL);
1363 
1364 	mutex_unlock(&local->mtx);
1365 
1366 	cfg80211_sched_scan_stopped(local->hw.wiphy, 0);
1367 }
1368 
1369 void ieee80211_sched_scan_stopped_work(struct work_struct *work)
1370 {
1371 	struct ieee80211_local *local =
1372 		container_of(work, struct ieee80211_local,
1373 			     sched_scan_stopped_work);
1374 
1375 	ieee80211_sched_scan_end(local);
1376 }
1377 
1378 void ieee80211_sched_scan_stopped(struct ieee80211_hw *hw)
1379 {
1380 	struct ieee80211_local *local = hw_to_local(hw);
1381 
1382 	trace_api_sched_scan_stopped(local);
1383 
1384 	/*
1385 	 * this shouldn't really happen, so for simplicity
1386 	 * simply ignore it, and let mac80211 reconfigure
1387 	 * the sched scan later on.
1388 	 */
1389 	if (local->in_reconfig)
1390 		return;
1391 
1392 	schedule_work(&local->sched_scan_stopped_work);
1393 }
1394 EXPORT_SYMBOL(ieee80211_sched_scan_stopped);
1395