xref: /linux/net/mac80211/scan.c (revision 7505576d1c1ac0cfe85fdf90999433dd8b673012)
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_scan(struct ieee80211_local *local,
524 			       struct ieee80211_sub_if_data *sdata)
525 {
526 	if (ieee80211_is_radar_required(local))
527 		return false;
528 
529 	if (!list_empty(&local->roc_list))
530 		return false;
531 
532 	if (sdata->vif.type == NL80211_IFTYPE_STATION &&
533 	    sdata->u.mgd.flags & IEEE80211_STA_CONNECTION_POLL)
534 		return false;
535 
536 	return true;
537 }
538 
539 void ieee80211_run_deferred_scan(struct ieee80211_local *local)
540 {
541 	lockdep_assert_held(&local->mtx);
542 
543 	if (!local->scan_req || local->scanning)
544 		return;
545 
546 	if (!ieee80211_can_scan(local,
547 				rcu_dereference_protected(
548 					local->scan_sdata,
549 					lockdep_is_held(&local->mtx))))
550 		return;
551 
552 	ieee80211_queue_delayed_work(&local->hw, &local->scan_work,
553 				     round_jiffies_relative(0));
554 }
555 
556 static void ieee80211_send_scan_probe_req(struct ieee80211_sub_if_data *sdata,
557 					  const u8 *src, const u8 *dst,
558 					  const u8 *ssid, size_t ssid_len,
559 					  const u8 *ie, size_t ie_len,
560 					  u32 ratemask, u32 flags, u32 tx_flags,
561 					  struct ieee80211_channel *channel)
562 {
563 	struct sk_buff *skb;
564 	u32 txdata_flags = 0;
565 
566 	skb = ieee80211_build_probe_req(sdata, src, dst, ratemask, channel,
567 					ssid, ssid_len,
568 					ie, ie_len, flags);
569 
570 	if (skb) {
571 		if (flags & IEEE80211_PROBE_FLAG_RANDOM_SN) {
572 			struct ieee80211_hdr *hdr = (void *)skb->data;
573 			u16 sn = get_random_u32();
574 
575 			txdata_flags |= IEEE80211_TX_NO_SEQNO;
576 			hdr->seq_ctrl =
577 				cpu_to_le16(IEEE80211_SN_TO_SEQ(sn));
578 		}
579 		IEEE80211_SKB_CB(skb)->flags |= tx_flags;
580 		ieee80211_tx_skb_tid_band(sdata, skb, 7, channel->band,
581 					  txdata_flags);
582 	}
583 }
584 
585 static void ieee80211_scan_state_send_probe(struct ieee80211_local *local,
586 					    unsigned long *next_delay)
587 {
588 	int i;
589 	struct ieee80211_sub_if_data *sdata;
590 	struct cfg80211_scan_request *scan_req;
591 	enum nl80211_band band = local->hw.conf.chandef.chan->band;
592 	u32 flags = 0, tx_flags;
593 
594 	scan_req = rcu_dereference_protected(local->scan_req,
595 					     lockdep_is_held(&local->mtx));
596 
597 	tx_flags = IEEE80211_TX_INTFL_OFFCHAN_TX_OK;
598 	if (scan_req->no_cck)
599 		tx_flags |= IEEE80211_TX_CTL_NO_CCK_RATE;
600 	if (scan_req->flags & NL80211_SCAN_FLAG_MIN_PREQ_CONTENT)
601 		flags |= IEEE80211_PROBE_FLAG_MIN_CONTENT;
602 	if (scan_req->flags & NL80211_SCAN_FLAG_RANDOM_SN)
603 		flags |= IEEE80211_PROBE_FLAG_RANDOM_SN;
604 
605 	sdata = rcu_dereference_protected(local->scan_sdata,
606 					  lockdep_is_held(&local->mtx));
607 
608 	for (i = 0; i < scan_req->n_ssids; i++)
609 		ieee80211_send_scan_probe_req(
610 			sdata, local->scan_addr, scan_req->bssid,
611 			scan_req->ssids[i].ssid, scan_req->ssids[i].ssid_len,
612 			scan_req->ie, scan_req->ie_len,
613 			scan_req->rates[band], flags,
614 			tx_flags, local->hw.conf.chandef.chan);
615 
616 	/*
617 	 * After sending probe requests, wait for probe responses
618 	 * on the channel.
619 	 */
620 	*next_delay = IEEE80211_CHANNEL_TIME;
621 	local->next_scan_state = SCAN_DECISION;
622 }
623 
624 static int __ieee80211_start_scan(struct ieee80211_sub_if_data *sdata,
625 				  struct cfg80211_scan_request *req)
626 {
627 	struct ieee80211_local *local = sdata->local;
628 	bool hw_scan = local->ops->hw_scan;
629 	int rc;
630 
631 	lockdep_assert_held(&local->mtx);
632 
633 	if (local->scan_req || ieee80211_is_radar_required(local))
634 		return -EBUSY;
635 
636 	if (!ieee80211_can_scan(local, sdata)) {
637 		/* wait for the work to finish/time out */
638 		rcu_assign_pointer(local->scan_req, req);
639 		rcu_assign_pointer(local->scan_sdata, sdata);
640 		return 0;
641 	}
642 
643  again:
644 	if (hw_scan) {
645 		u8 *ies;
646 
647 		local->hw_scan_ies_bufsize = local->scan_ies_len + req->ie_len;
648 
649 		if (ieee80211_hw_check(&local->hw, SINGLE_SCAN_ON_ALL_BANDS)) {
650 			int i, n_bands = 0;
651 			u8 bands_counted = 0;
652 
653 			for (i = 0; i < req->n_channels; i++) {
654 				if (bands_counted & BIT(req->channels[i]->band))
655 					continue;
656 				bands_counted |= BIT(req->channels[i]->band);
657 				n_bands++;
658 			}
659 
660 			local->hw_scan_ies_bufsize *= n_bands;
661 		}
662 
663 		local->hw_scan_req = kmalloc(
664 				sizeof(*local->hw_scan_req) +
665 				req->n_channels * sizeof(req->channels[0]) +
666 				local->hw_scan_ies_bufsize, GFP_KERNEL);
667 		if (!local->hw_scan_req)
668 			return -ENOMEM;
669 
670 		local->hw_scan_req->req.ssids = req->ssids;
671 		local->hw_scan_req->req.n_ssids = req->n_ssids;
672 		ies = (u8 *)local->hw_scan_req +
673 			sizeof(*local->hw_scan_req) +
674 			req->n_channels * sizeof(req->channels[0]);
675 		local->hw_scan_req->req.ie = ies;
676 		local->hw_scan_req->req.flags = req->flags;
677 		eth_broadcast_addr(local->hw_scan_req->req.bssid);
678 		local->hw_scan_req->req.duration = req->duration;
679 		local->hw_scan_req->req.duration_mandatory =
680 			req->duration_mandatory;
681 
682 		local->hw_scan_band = 0;
683 
684 		/*
685 		 * After allocating local->hw_scan_req, we must
686 		 * go through until ieee80211_prep_hw_scan(), so
687 		 * anything that might be changed here and leave
688 		 * this function early must not go after this
689 		 * allocation.
690 		 */
691 	}
692 
693 	rcu_assign_pointer(local->scan_req, req);
694 	rcu_assign_pointer(local->scan_sdata, sdata);
695 
696 	if (req->flags & NL80211_SCAN_FLAG_RANDOM_ADDR)
697 		get_random_mask_addr(local->scan_addr,
698 				     req->mac_addr,
699 				     req->mac_addr_mask);
700 	else
701 		memcpy(local->scan_addr, sdata->vif.addr, ETH_ALEN);
702 
703 	if (hw_scan) {
704 		__set_bit(SCAN_HW_SCANNING, &local->scanning);
705 	} else if ((req->n_channels == 1) &&
706 		   (req->channels[0] == local->_oper_chandef.chan)) {
707 		/*
708 		 * If we are scanning only on the operating channel
709 		 * then we do not need to stop normal activities
710 		 */
711 		unsigned long next_delay;
712 
713 		__set_bit(SCAN_ONCHANNEL_SCANNING, &local->scanning);
714 
715 		ieee80211_recalc_idle(local);
716 
717 		/* Notify driver scan is starting, keep order of operations
718 		 * same as normal software scan, in case that matters. */
719 		drv_sw_scan_start(local, sdata, local->scan_addr);
720 
721 		ieee80211_configure_filter(local); /* accept probe-responses */
722 
723 		/* We need to ensure power level is at max for scanning. */
724 		ieee80211_hw_config(local, 0);
725 
726 		if ((req->channels[0]->flags & (IEEE80211_CHAN_NO_IR |
727 						IEEE80211_CHAN_RADAR)) ||
728 		    !req->n_ssids) {
729 			next_delay = IEEE80211_PASSIVE_CHANNEL_TIME;
730 		} else {
731 			ieee80211_scan_state_send_probe(local, &next_delay);
732 			next_delay = IEEE80211_CHANNEL_TIME;
733 		}
734 
735 		/* Now, just wait a bit and we are all done! */
736 		ieee80211_queue_delayed_work(&local->hw, &local->scan_work,
737 					     next_delay);
738 		return 0;
739 	} else {
740 		/* Do normal software scan */
741 		__set_bit(SCAN_SW_SCANNING, &local->scanning);
742 	}
743 
744 	ieee80211_recalc_idle(local);
745 
746 	if (hw_scan) {
747 		WARN_ON(!ieee80211_prep_hw_scan(local));
748 		rc = drv_hw_scan(local, sdata, local->hw_scan_req);
749 	} else {
750 		rc = ieee80211_start_sw_scan(local, sdata);
751 	}
752 
753 	if (rc) {
754 		kfree(local->hw_scan_req);
755 		local->hw_scan_req = NULL;
756 		local->scanning = 0;
757 
758 		ieee80211_recalc_idle(local);
759 
760 		local->scan_req = NULL;
761 		RCU_INIT_POINTER(local->scan_sdata, NULL);
762 	}
763 
764 	if (hw_scan && rc == 1) {
765 		/*
766 		 * we can't fall back to software for P2P-GO
767 		 * as it must update NoA etc.
768 		 */
769 		if (ieee80211_vif_type_p2p(&sdata->vif) ==
770 				NL80211_IFTYPE_P2P_GO)
771 			return -EOPNOTSUPP;
772 		hw_scan = false;
773 		goto again;
774 	}
775 
776 	return rc;
777 }
778 
779 static unsigned long
780 ieee80211_scan_get_channel_time(struct ieee80211_channel *chan)
781 {
782 	/*
783 	 * TODO: channel switching also consumes quite some time,
784 	 * add that delay as well to get a better estimation
785 	 */
786 	if (chan->flags & (IEEE80211_CHAN_NO_IR | IEEE80211_CHAN_RADAR))
787 		return IEEE80211_PASSIVE_CHANNEL_TIME;
788 	return IEEE80211_PROBE_DELAY + IEEE80211_CHANNEL_TIME;
789 }
790 
791 static void ieee80211_scan_state_decision(struct ieee80211_local *local,
792 					  unsigned long *next_delay)
793 {
794 	bool associated = false;
795 	bool tx_empty = true;
796 	bool bad_latency;
797 	struct ieee80211_sub_if_data *sdata;
798 	struct ieee80211_channel *next_chan;
799 	enum mac80211_scan_state next_scan_state;
800 	struct cfg80211_scan_request *scan_req;
801 
802 	/*
803 	 * check if at least one STA interface is associated,
804 	 * check if at least one STA interface has pending tx frames
805 	 * and grab the lowest used beacon interval
806 	 */
807 	mutex_lock(&local->iflist_mtx);
808 	list_for_each_entry(sdata, &local->interfaces, list) {
809 		if (!ieee80211_sdata_running(sdata))
810 			continue;
811 
812 		if (sdata->vif.type == NL80211_IFTYPE_STATION) {
813 			if (sdata->u.mgd.associated) {
814 				associated = true;
815 
816 				if (!qdisc_all_tx_empty(sdata->dev)) {
817 					tx_empty = false;
818 					break;
819 				}
820 			}
821 		}
822 	}
823 	mutex_unlock(&local->iflist_mtx);
824 
825 	scan_req = rcu_dereference_protected(local->scan_req,
826 					     lockdep_is_held(&local->mtx));
827 
828 	next_chan = scan_req->channels[local->scan_channel_idx];
829 
830 	/*
831 	 * we're currently scanning a different channel, let's
832 	 * see if we can scan another channel without interfering
833 	 * with the current traffic situation.
834 	 *
835 	 * Keep good latency, do not stay off-channel more than 125 ms.
836 	 */
837 
838 	bad_latency = time_after(jiffies +
839 				 ieee80211_scan_get_channel_time(next_chan),
840 				 local->leave_oper_channel_time + HZ / 8);
841 
842 	if (associated && !tx_empty) {
843 		if (scan_req->flags & NL80211_SCAN_FLAG_LOW_PRIORITY)
844 			next_scan_state = SCAN_ABORT;
845 		else
846 			next_scan_state = SCAN_SUSPEND;
847 	} else if (associated && bad_latency) {
848 		next_scan_state = SCAN_SUSPEND;
849 	} else {
850 		next_scan_state = SCAN_SET_CHANNEL;
851 	}
852 
853 	local->next_scan_state = next_scan_state;
854 
855 	*next_delay = 0;
856 }
857 
858 static void ieee80211_scan_state_set_channel(struct ieee80211_local *local,
859 					     unsigned long *next_delay)
860 {
861 	int skip;
862 	struct ieee80211_channel *chan;
863 	enum nl80211_bss_scan_width oper_scan_width;
864 	struct cfg80211_scan_request *scan_req;
865 
866 	scan_req = rcu_dereference_protected(local->scan_req,
867 					     lockdep_is_held(&local->mtx));
868 
869 	skip = 0;
870 	chan = scan_req->channels[local->scan_channel_idx];
871 
872 	local->scan_chandef.chan = chan;
873 	local->scan_chandef.center_freq1 = chan->center_freq;
874 	local->scan_chandef.center_freq2 = 0;
875 	switch (scan_req->scan_width) {
876 	case NL80211_BSS_CHAN_WIDTH_5:
877 		local->scan_chandef.width = NL80211_CHAN_WIDTH_5;
878 		break;
879 	case NL80211_BSS_CHAN_WIDTH_10:
880 		local->scan_chandef.width = NL80211_CHAN_WIDTH_10;
881 		break;
882 	case NL80211_BSS_CHAN_WIDTH_20:
883 		/* If scanning on oper channel, use whatever channel-type
884 		 * is currently in use.
885 		 */
886 		oper_scan_width = cfg80211_chandef_to_scan_width(
887 					&local->_oper_chandef);
888 		if (chan == local->_oper_chandef.chan &&
889 		    oper_scan_width == scan_req->scan_width)
890 			local->scan_chandef = local->_oper_chandef;
891 		else
892 			local->scan_chandef.width = NL80211_CHAN_WIDTH_20_NOHT;
893 		break;
894 	}
895 
896 	if (ieee80211_hw_config(local, IEEE80211_CONF_CHANGE_CHANNEL))
897 		skip = 1;
898 
899 	/* advance state machine to next channel/band */
900 	local->scan_channel_idx++;
901 
902 	if (skip) {
903 		/* if we skip this channel return to the decision state */
904 		local->next_scan_state = SCAN_DECISION;
905 		return;
906 	}
907 
908 	/*
909 	 * Probe delay is used to update the NAV, cf. 11.1.3.2.2
910 	 * (which unfortunately doesn't say _why_ step a) is done,
911 	 * but it waits for the probe delay or until a frame is
912 	 * received - and the received frame would update the NAV).
913 	 * For now, we do not support waiting until a frame is
914 	 * received.
915 	 *
916 	 * In any case, it is not necessary for a passive scan.
917 	 */
918 	if ((chan->flags & (IEEE80211_CHAN_NO_IR | IEEE80211_CHAN_RADAR)) ||
919 	    !scan_req->n_ssids) {
920 		*next_delay = IEEE80211_PASSIVE_CHANNEL_TIME;
921 		local->next_scan_state = SCAN_DECISION;
922 		return;
923 	}
924 
925 	/* active scan, send probes */
926 	*next_delay = IEEE80211_PROBE_DELAY;
927 	local->next_scan_state = SCAN_SEND_PROBE;
928 }
929 
930 static void ieee80211_scan_state_suspend(struct ieee80211_local *local,
931 					 unsigned long *next_delay)
932 {
933 	/* switch back to the operating channel */
934 	local->scan_chandef.chan = NULL;
935 	ieee80211_hw_config(local, IEEE80211_CONF_CHANGE_CHANNEL);
936 
937 	/* disable PS */
938 	ieee80211_offchannel_return(local);
939 
940 	*next_delay = HZ / 5;
941 	/* afterwards, resume scan & go to next channel */
942 	local->next_scan_state = SCAN_RESUME;
943 }
944 
945 static void ieee80211_scan_state_resume(struct ieee80211_local *local,
946 					unsigned long *next_delay)
947 {
948 	ieee80211_offchannel_stop_vifs(local);
949 
950 	if (local->ops->flush) {
951 		ieee80211_flush_queues(local, NULL, false);
952 		*next_delay = 0;
953 	} else
954 		*next_delay = HZ / 10;
955 
956 	/* remember when we left the operating channel */
957 	local->leave_oper_channel_time = jiffies;
958 
959 	/* advance to the next channel to be scanned */
960 	local->next_scan_state = SCAN_SET_CHANNEL;
961 }
962 
963 void ieee80211_scan_work(struct work_struct *work)
964 {
965 	struct ieee80211_local *local =
966 		container_of(work, struct ieee80211_local, scan_work.work);
967 	struct ieee80211_sub_if_data *sdata;
968 	struct cfg80211_scan_request *scan_req;
969 	unsigned long next_delay = 0;
970 	bool aborted;
971 
972 	mutex_lock(&local->mtx);
973 
974 	if (!ieee80211_can_run_worker(local)) {
975 		aborted = true;
976 		goto out_complete;
977 	}
978 
979 	sdata = rcu_dereference_protected(local->scan_sdata,
980 					  lockdep_is_held(&local->mtx));
981 	scan_req = rcu_dereference_protected(local->scan_req,
982 					     lockdep_is_held(&local->mtx));
983 
984 	/* When scanning on-channel, the first-callback means completed. */
985 	if (test_bit(SCAN_ONCHANNEL_SCANNING, &local->scanning)) {
986 		aborted = test_and_clear_bit(SCAN_ABORTED, &local->scanning);
987 		goto out_complete;
988 	}
989 
990 	if (test_and_clear_bit(SCAN_COMPLETED, &local->scanning)) {
991 		aborted = test_and_clear_bit(SCAN_ABORTED, &local->scanning);
992 		goto out_complete;
993 	}
994 
995 	if (!sdata || !scan_req)
996 		goto out;
997 
998 	if (!local->scanning) {
999 		int rc;
1000 
1001 		RCU_INIT_POINTER(local->scan_req, NULL);
1002 		RCU_INIT_POINTER(local->scan_sdata, NULL);
1003 
1004 		rc = __ieee80211_start_scan(sdata, scan_req);
1005 		if (rc) {
1006 			/* need to complete scan in cfg80211 */
1007 			rcu_assign_pointer(local->scan_req, scan_req);
1008 			aborted = true;
1009 			goto out_complete;
1010 		} else
1011 			goto out;
1012 	}
1013 
1014 	/*
1015 	 * as long as no delay is required advance immediately
1016 	 * without scheduling a new work
1017 	 */
1018 	do {
1019 		if (!ieee80211_sdata_running(sdata)) {
1020 			aborted = true;
1021 			goto out_complete;
1022 		}
1023 
1024 		switch (local->next_scan_state) {
1025 		case SCAN_DECISION:
1026 			/* if no more bands/channels left, complete scan */
1027 			if (local->scan_channel_idx >= scan_req->n_channels) {
1028 				aborted = false;
1029 				goto out_complete;
1030 			}
1031 			ieee80211_scan_state_decision(local, &next_delay);
1032 			break;
1033 		case SCAN_SET_CHANNEL:
1034 			ieee80211_scan_state_set_channel(local, &next_delay);
1035 			break;
1036 		case SCAN_SEND_PROBE:
1037 			ieee80211_scan_state_send_probe(local, &next_delay);
1038 			break;
1039 		case SCAN_SUSPEND:
1040 			ieee80211_scan_state_suspend(local, &next_delay);
1041 			break;
1042 		case SCAN_RESUME:
1043 			ieee80211_scan_state_resume(local, &next_delay);
1044 			break;
1045 		case SCAN_ABORT:
1046 			aborted = true;
1047 			goto out_complete;
1048 		}
1049 	} while (next_delay == 0);
1050 
1051 	ieee80211_queue_delayed_work(&local->hw, &local->scan_work, next_delay);
1052 	goto out;
1053 
1054 out_complete:
1055 	__ieee80211_scan_completed(&local->hw, aborted);
1056 out:
1057 	mutex_unlock(&local->mtx);
1058 }
1059 
1060 int ieee80211_request_scan(struct ieee80211_sub_if_data *sdata,
1061 			   struct cfg80211_scan_request *req)
1062 {
1063 	int res;
1064 
1065 	mutex_lock(&sdata->local->mtx);
1066 	res = __ieee80211_start_scan(sdata, req);
1067 	mutex_unlock(&sdata->local->mtx);
1068 
1069 	return res;
1070 }
1071 
1072 int ieee80211_request_ibss_scan(struct ieee80211_sub_if_data *sdata,
1073 				const u8 *ssid, u8 ssid_len,
1074 				struct ieee80211_channel **channels,
1075 				unsigned int n_channels,
1076 				enum nl80211_bss_scan_width scan_width)
1077 {
1078 	struct ieee80211_local *local = sdata->local;
1079 	int ret = -EBUSY, i, n_ch = 0;
1080 	enum nl80211_band band;
1081 
1082 	mutex_lock(&local->mtx);
1083 
1084 	/* busy scanning */
1085 	if (local->scan_req)
1086 		goto unlock;
1087 
1088 	/* fill internal scan request */
1089 	if (!channels) {
1090 		int max_n;
1091 
1092 		for (band = 0; band < NUM_NL80211_BANDS; band++) {
1093 			if (!local->hw.wiphy->bands[band])
1094 				continue;
1095 
1096 			max_n = local->hw.wiphy->bands[band]->n_channels;
1097 			for (i = 0; i < max_n; i++) {
1098 				struct ieee80211_channel *tmp_ch =
1099 				    &local->hw.wiphy->bands[band]->channels[i];
1100 
1101 				if (tmp_ch->flags & (IEEE80211_CHAN_NO_IR |
1102 						     IEEE80211_CHAN_DISABLED))
1103 					continue;
1104 
1105 				local->int_scan_req->channels[n_ch] = tmp_ch;
1106 				n_ch++;
1107 			}
1108 		}
1109 
1110 		if (WARN_ON_ONCE(n_ch == 0))
1111 			goto unlock;
1112 
1113 		local->int_scan_req->n_channels = n_ch;
1114 	} else {
1115 		for (i = 0; i < n_channels; i++) {
1116 			if (channels[i]->flags & (IEEE80211_CHAN_NO_IR |
1117 						  IEEE80211_CHAN_DISABLED))
1118 				continue;
1119 
1120 			local->int_scan_req->channels[n_ch] = channels[i];
1121 			n_ch++;
1122 		}
1123 
1124 		if (WARN_ON_ONCE(n_ch == 0))
1125 			goto unlock;
1126 
1127 		local->int_scan_req->n_channels = n_ch;
1128 	}
1129 
1130 	local->int_scan_req->ssids = &local->scan_ssid;
1131 	local->int_scan_req->n_ssids = 1;
1132 	local->int_scan_req->scan_width = scan_width;
1133 	memcpy(local->int_scan_req->ssids[0].ssid, ssid, IEEE80211_MAX_SSID_LEN);
1134 	local->int_scan_req->ssids[0].ssid_len = ssid_len;
1135 
1136 	ret = __ieee80211_start_scan(sdata, sdata->local->int_scan_req);
1137  unlock:
1138 	mutex_unlock(&local->mtx);
1139 	return ret;
1140 }
1141 
1142 /*
1143  * Only call this function when a scan can't be queued -- under RTNL.
1144  */
1145 void ieee80211_scan_cancel(struct ieee80211_local *local)
1146 {
1147 	/*
1148 	 * We are canceling software scan, or deferred scan that was not
1149 	 * yet really started (see __ieee80211_start_scan ).
1150 	 *
1151 	 * Regarding hardware scan:
1152 	 * - we can not call  __ieee80211_scan_completed() as when
1153 	 *   SCAN_HW_SCANNING bit is set this function change
1154 	 *   local->hw_scan_req to operate on 5G band, what race with
1155 	 *   driver which can use local->hw_scan_req
1156 	 *
1157 	 * - we can not cancel scan_work since driver can schedule it
1158 	 *   by ieee80211_scan_completed(..., true) to finish scan
1159 	 *
1160 	 * Hence we only call the cancel_hw_scan() callback, but the low-level
1161 	 * driver is still responsible for calling ieee80211_scan_completed()
1162 	 * after the scan was completed/aborted.
1163 	 */
1164 
1165 	mutex_lock(&local->mtx);
1166 	if (!local->scan_req)
1167 		goto out;
1168 
1169 	/*
1170 	 * We have a scan running and the driver already reported completion,
1171 	 * but the worker hasn't run yet or is stuck on the mutex - mark it as
1172 	 * cancelled.
1173 	 */
1174 	if (test_bit(SCAN_HW_SCANNING, &local->scanning) &&
1175 	    test_bit(SCAN_COMPLETED, &local->scanning)) {
1176 		set_bit(SCAN_HW_CANCELLED, &local->scanning);
1177 		goto out;
1178 	}
1179 
1180 	if (test_bit(SCAN_HW_SCANNING, &local->scanning)) {
1181 		/*
1182 		 * Make sure that __ieee80211_scan_completed doesn't trigger a
1183 		 * scan on another band.
1184 		 */
1185 		set_bit(SCAN_HW_CANCELLED, &local->scanning);
1186 		if (local->ops->cancel_hw_scan)
1187 			drv_cancel_hw_scan(local,
1188 				rcu_dereference_protected(local->scan_sdata,
1189 						lockdep_is_held(&local->mtx)));
1190 		goto out;
1191 	}
1192 
1193 	/*
1194 	 * If the work is currently running, it must be blocked on
1195 	 * the mutex, but we'll set scan_sdata = NULL and it'll
1196 	 * simply exit once it acquires the mutex.
1197 	 */
1198 	cancel_delayed_work(&local->scan_work);
1199 	/* and clean up */
1200 	memset(&local->scan_info, 0, sizeof(local->scan_info));
1201 	__ieee80211_scan_completed(&local->hw, true);
1202 out:
1203 	mutex_unlock(&local->mtx);
1204 }
1205 
1206 int __ieee80211_request_sched_scan_start(struct ieee80211_sub_if_data *sdata,
1207 					struct cfg80211_sched_scan_request *req)
1208 {
1209 	struct ieee80211_local *local = sdata->local;
1210 	struct ieee80211_scan_ies sched_scan_ies = {};
1211 	struct cfg80211_chan_def chandef;
1212 	int ret, i, iebufsz, num_bands = 0;
1213 	u32 rate_masks[NUM_NL80211_BANDS] = {};
1214 	u8 bands_used = 0;
1215 	u8 *ie;
1216 	u32 flags = 0;
1217 
1218 	iebufsz = local->scan_ies_len + req->ie_len;
1219 
1220 	lockdep_assert_held(&local->mtx);
1221 
1222 	if (!local->ops->sched_scan_start)
1223 		return -ENOTSUPP;
1224 
1225 	for (i = 0; i < NUM_NL80211_BANDS; i++) {
1226 		if (local->hw.wiphy->bands[i]) {
1227 			bands_used |= BIT(i);
1228 			rate_masks[i] = (u32) -1;
1229 			num_bands++;
1230 		}
1231 	}
1232 
1233 	if (req->flags & NL80211_SCAN_FLAG_MIN_PREQ_CONTENT)
1234 		flags |= IEEE80211_PROBE_FLAG_MIN_CONTENT;
1235 
1236 	ie = kcalloc(iebufsz, num_bands, GFP_KERNEL);
1237 	if (!ie) {
1238 		ret = -ENOMEM;
1239 		goto out;
1240 	}
1241 
1242 	ieee80211_prepare_scan_chandef(&chandef, req->scan_width);
1243 
1244 	ieee80211_build_preq_ies(local, ie, num_bands * iebufsz,
1245 				 &sched_scan_ies, req->ie,
1246 				 req->ie_len, bands_used, rate_masks, &chandef,
1247 				 flags);
1248 
1249 	ret = drv_sched_scan_start(local, sdata, req, &sched_scan_ies);
1250 	if (ret == 0) {
1251 		rcu_assign_pointer(local->sched_scan_sdata, sdata);
1252 		rcu_assign_pointer(local->sched_scan_req, req);
1253 	}
1254 
1255 	kfree(ie);
1256 
1257 out:
1258 	if (ret) {
1259 		/* Clean in case of failure after HW restart or upon resume. */
1260 		RCU_INIT_POINTER(local->sched_scan_sdata, NULL);
1261 		RCU_INIT_POINTER(local->sched_scan_req, NULL);
1262 	}
1263 
1264 	return ret;
1265 }
1266 
1267 int ieee80211_request_sched_scan_start(struct ieee80211_sub_if_data *sdata,
1268 				       struct cfg80211_sched_scan_request *req)
1269 {
1270 	struct ieee80211_local *local = sdata->local;
1271 	int ret;
1272 
1273 	mutex_lock(&local->mtx);
1274 
1275 	if (rcu_access_pointer(local->sched_scan_sdata)) {
1276 		mutex_unlock(&local->mtx);
1277 		return -EBUSY;
1278 	}
1279 
1280 	ret = __ieee80211_request_sched_scan_start(sdata, req);
1281 
1282 	mutex_unlock(&local->mtx);
1283 	return ret;
1284 }
1285 
1286 int ieee80211_request_sched_scan_stop(struct ieee80211_local *local)
1287 {
1288 	struct ieee80211_sub_if_data *sched_scan_sdata;
1289 	int ret = -ENOENT;
1290 
1291 	mutex_lock(&local->mtx);
1292 
1293 	if (!local->ops->sched_scan_stop) {
1294 		ret = -ENOTSUPP;
1295 		goto out;
1296 	}
1297 
1298 	/* We don't want to restart sched scan anymore. */
1299 	RCU_INIT_POINTER(local->sched_scan_req, NULL);
1300 
1301 	sched_scan_sdata = rcu_dereference_protected(local->sched_scan_sdata,
1302 						lockdep_is_held(&local->mtx));
1303 	if (sched_scan_sdata) {
1304 		ret = drv_sched_scan_stop(local, sched_scan_sdata);
1305 		if (!ret)
1306 			RCU_INIT_POINTER(local->sched_scan_sdata, NULL);
1307 	}
1308 out:
1309 	mutex_unlock(&local->mtx);
1310 
1311 	return ret;
1312 }
1313 
1314 void ieee80211_sched_scan_results(struct ieee80211_hw *hw)
1315 {
1316 	struct ieee80211_local *local = hw_to_local(hw);
1317 
1318 	trace_api_sched_scan_results(local);
1319 
1320 	cfg80211_sched_scan_results(hw->wiphy, 0);
1321 }
1322 EXPORT_SYMBOL(ieee80211_sched_scan_results);
1323 
1324 void ieee80211_sched_scan_end(struct ieee80211_local *local)
1325 {
1326 	mutex_lock(&local->mtx);
1327 
1328 	if (!rcu_access_pointer(local->sched_scan_sdata)) {
1329 		mutex_unlock(&local->mtx);
1330 		return;
1331 	}
1332 
1333 	RCU_INIT_POINTER(local->sched_scan_sdata, NULL);
1334 
1335 	/* If sched scan was aborted by the driver. */
1336 	RCU_INIT_POINTER(local->sched_scan_req, NULL);
1337 
1338 	mutex_unlock(&local->mtx);
1339 
1340 	cfg80211_sched_scan_stopped(local->hw.wiphy, 0);
1341 }
1342 
1343 void ieee80211_sched_scan_stopped_work(struct work_struct *work)
1344 {
1345 	struct ieee80211_local *local =
1346 		container_of(work, struct ieee80211_local,
1347 			     sched_scan_stopped_work);
1348 
1349 	ieee80211_sched_scan_end(local);
1350 }
1351 
1352 void ieee80211_sched_scan_stopped(struct ieee80211_hw *hw)
1353 {
1354 	struct ieee80211_local *local = hw_to_local(hw);
1355 
1356 	trace_api_sched_scan_stopped(local);
1357 
1358 	/*
1359 	 * this shouldn't really happen, so for simplicity
1360 	 * simply ignore it, and let mac80211 reconfigure
1361 	 * the sched scan later on.
1362 	 */
1363 	if (local->in_reconfig)
1364 		return;
1365 
1366 	schedule_work(&local->sched_scan_stopped_work);
1367 }
1368 EXPORT_SYMBOL(ieee80211_sched_scan_stopped);
1369