xref: /openbmc/linux/net/mac80211/scan.c (revision be709d48)
1 /*
2  * Scanning implementation
3  *
4  * Copyright 2003, Jouni Malinen <jkmaline@cc.hut.fi>
5  * Copyright 2004, Instant802 Networks, Inc.
6  * Copyright 2005, Devicescape Software, Inc.
7  * Copyright 2006-2007	Jiri Benc <jbenc@suse.cz>
8  * Copyright 2007, Michael Wu <flamingice@sourmilk.net>
9  * Copyright 2013-2015  Intel Mobile Communications GmbH
10  * Copyright 2016-2017  Intel Deutschland GmbH
11  * Copyright (C) 2018-2019 Intel Corporation
12  *
13  * This program is free software; you can redistribute it and/or modify
14  * it under the terms of the GNU General Public License version 2 as
15  * published by the Free Software Foundation.
16  */
17 
18 #include <linux/if_arp.h>
19 #include <linux/etherdevice.h>
20 #include <linux/rtnetlink.h>
21 #include <net/sch_generic.h>
22 #include <linux/slab.h>
23 #include <linux/export.h>
24 #include <linux/random.h>
25 #include <net/mac80211.h>
26 
27 #include "ieee80211_i.h"
28 #include "driver-ops.h"
29 #include "mesh.h"
30 
31 #define IEEE80211_PROBE_DELAY (HZ / 33)
32 #define IEEE80211_CHANNEL_TIME (HZ / 33)
33 #define IEEE80211_PASSIVE_CHANNEL_TIME (HZ / 9)
34 
35 void ieee80211_rx_bss_put(struct ieee80211_local *local,
36 			  struct ieee80211_bss *bss)
37 {
38 	if (!bss)
39 		return;
40 	cfg80211_put_bss(local->hw.wiphy,
41 			 container_of((void *)bss, struct cfg80211_bss, priv));
42 }
43 
44 static bool is_uapsd_supported(struct ieee802_11_elems *elems)
45 {
46 	u8 qos_info;
47 
48 	if (elems->wmm_info && elems->wmm_info_len == 7
49 	    && elems->wmm_info[5] == 1)
50 		qos_info = elems->wmm_info[6];
51 	else if (elems->wmm_param && elems->wmm_param_len == 24
52 		 && elems->wmm_param[5] == 1)
53 		qos_info = elems->wmm_param[6];
54 	else
55 		/* no valid wmm information or parameter element found */
56 		return false;
57 
58 	return qos_info & IEEE80211_WMM_IE_AP_QOSINFO_UAPSD;
59 }
60 
61 static void
62 ieee80211_update_bss_from_elems(struct ieee80211_local *local,
63 				struct ieee80211_bss *bss,
64 				struct ieee802_11_elems *elems,
65 				struct ieee80211_rx_status *rx_status,
66 				bool beacon)
67 {
68 	int clen, srlen;
69 
70 	if (beacon)
71 		bss->device_ts_beacon = rx_status->device_timestamp;
72 	else
73 		bss->device_ts_presp = rx_status->device_timestamp;
74 
75 	if (elems->parse_error) {
76 		if (beacon)
77 			bss->corrupt_data |= IEEE80211_BSS_CORRUPT_BEACON;
78 		else
79 			bss->corrupt_data |= IEEE80211_BSS_CORRUPT_PROBE_RESP;
80 	} else {
81 		if (beacon)
82 			bss->corrupt_data &= ~IEEE80211_BSS_CORRUPT_BEACON;
83 		else
84 			bss->corrupt_data &= ~IEEE80211_BSS_CORRUPT_PROBE_RESP;
85 	}
86 
87 	/* save the ERP value so that it is available at association time */
88 	if (elems->erp_info && (!elems->parse_error ||
89 				!(bss->valid_data & IEEE80211_BSS_VALID_ERP))) {
90 		bss->erp_value = elems->erp_info[0];
91 		bss->has_erp_value = true;
92 		if (!elems->parse_error)
93 			bss->valid_data |= IEEE80211_BSS_VALID_ERP;
94 	}
95 
96 	/* replace old supported rates if we get new values */
97 	if (!elems->parse_error ||
98 	    !(bss->valid_data & IEEE80211_BSS_VALID_RATES)) {
99 		srlen = 0;
100 		if (elems->supp_rates) {
101 			clen = IEEE80211_MAX_SUPP_RATES;
102 			if (clen > elems->supp_rates_len)
103 				clen = elems->supp_rates_len;
104 			memcpy(bss->supp_rates, elems->supp_rates, clen);
105 			srlen += clen;
106 		}
107 		if (elems->ext_supp_rates) {
108 			clen = IEEE80211_MAX_SUPP_RATES - srlen;
109 			if (clen > elems->ext_supp_rates_len)
110 				clen = elems->ext_supp_rates_len;
111 			memcpy(bss->supp_rates + srlen, elems->ext_supp_rates,
112 			       clen);
113 			srlen += clen;
114 		}
115 		if (srlen) {
116 			bss->supp_rates_len = srlen;
117 			if (!elems->parse_error)
118 				bss->valid_data |= IEEE80211_BSS_VALID_RATES;
119 		}
120 	}
121 
122 	if (!elems->parse_error ||
123 	    !(bss->valid_data & IEEE80211_BSS_VALID_WMM)) {
124 		bss->wmm_used = elems->wmm_param || elems->wmm_info;
125 		bss->uapsd_supported = is_uapsd_supported(elems);
126 		if (!elems->parse_error)
127 			bss->valid_data |= IEEE80211_BSS_VALID_WMM;
128 	}
129 
130 	if (beacon) {
131 		struct ieee80211_supported_band *sband =
132 			local->hw.wiphy->bands[rx_status->band];
133 		if (!(rx_status->encoding == RX_ENC_HT) &&
134 		    !(rx_status->encoding == RX_ENC_VHT))
135 			bss->beacon_rate =
136 				&sband->bitrates[rx_status->rate_idx];
137 	}
138 }
139 
140 struct ieee80211_bss *
141 ieee80211_bss_info_update(struct ieee80211_local *local,
142 			  struct ieee80211_rx_status *rx_status,
143 			  struct ieee80211_mgmt *mgmt, size_t len,
144 			  struct ieee80211_channel *channel)
145 {
146 	bool beacon = ieee80211_is_beacon(mgmt->frame_control);
147 	struct cfg80211_bss *cbss, *non_tx_cbss;
148 	struct ieee80211_bss *bss, *non_tx_bss;
149 	struct cfg80211_inform_bss bss_meta = {
150 		.boottime_ns = rx_status->boottime_ns,
151 	};
152 	bool signal_valid;
153 	struct ieee80211_sub_if_data *scan_sdata;
154 	struct ieee802_11_elems elems;
155 	size_t baselen;
156 	u8 *elements;
157 
158 	if (rx_status->flag & RX_FLAG_NO_SIGNAL_VAL)
159 		bss_meta.signal = 0; /* invalid signal indication */
160 	else if (ieee80211_hw_check(&local->hw, SIGNAL_DBM))
161 		bss_meta.signal = rx_status->signal * 100;
162 	else if (ieee80211_hw_check(&local->hw, SIGNAL_UNSPEC))
163 		bss_meta.signal = (rx_status->signal * 100) / local->hw.max_signal;
164 
165 	bss_meta.scan_width = NL80211_BSS_CHAN_WIDTH_20;
166 	if (rx_status->bw == RATE_INFO_BW_5)
167 		bss_meta.scan_width = NL80211_BSS_CHAN_WIDTH_5;
168 	else if (rx_status->bw == RATE_INFO_BW_10)
169 		bss_meta.scan_width = NL80211_BSS_CHAN_WIDTH_10;
170 
171 	bss_meta.chan = channel;
172 
173 	rcu_read_lock();
174 	scan_sdata = rcu_dereference(local->scan_sdata);
175 	if (scan_sdata && scan_sdata->vif.type == NL80211_IFTYPE_STATION &&
176 	    scan_sdata->vif.bss_conf.assoc &&
177 	    ieee80211_have_rx_timestamp(rx_status)) {
178 		bss_meta.parent_tsf =
179 			ieee80211_calculate_rx_timestamp(local, rx_status,
180 							 len + FCS_LEN, 24);
181 		ether_addr_copy(bss_meta.parent_bssid,
182 				scan_sdata->vif.bss_conf.bssid);
183 	}
184 	rcu_read_unlock();
185 
186 	cbss = cfg80211_inform_bss_frame_data(local->hw.wiphy, &bss_meta,
187 					      mgmt, len, GFP_ATOMIC);
188 	if (!cbss)
189 		return NULL;
190 
191 	if (ieee80211_is_probe_resp(mgmt->frame_control)) {
192 		elements = mgmt->u.probe_resp.variable;
193 		baselen = offsetof(struct ieee80211_mgmt,
194 				   u.probe_resp.variable);
195 	} else {
196 		baselen = offsetof(struct ieee80211_mgmt, u.beacon.variable);
197 		elements = mgmt->u.beacon.variable;
198 	}
199 
200 	if (baselen > len)
201 		return NULL;
202 
203 	ieee802_11_parse_elems(elements, len - baselen, false, &elems,
204 			       mgmt->bssid, cbss->bssid);
205 
206 	/* In case the signal is invalid update the status */
207 	signal_valid = abs(channel->center_freq - cbss->channel->center_freq)
208 		<= local->hw.wiphy->max_adj_channel_rssi_comp;
209 	if (!signal_valid)
210 		rx_status->flag |= RX_FLAG_NO_SIGNAL_VAL;
211 
212 	bss = (void *)cbss->priv;
213 	ieee80211_update_bss_from_elems(local, bss, &elems, rx_status, beacon);
214 
215 	list_for_each_entry(non_tx_cbss, &cbss->nontrans_list, nontrans_list) {
216 		non_tx_bss = (void *)non_tx_cbss->priv;
217 
218 		ieee80211_update_bss_from_elems(local, non_tx_bss, &elems,
219 						rx_status, beacon);
220 	}
221 
222 	return bss;
223 }
224 
225 static bool ieee80211_scan_accept_presp(struct ieee80211_sub_if_data *sdata,
226 					u32 scan_flags, const u8 *da)
227 {
228 	if (!sdata)
229 		return false;
230 	/* accept broadcast for OCE */
231 	if (scan_flags & NL80211_SCAN_FLAG_ACCEPT_BCAST_PROBE_RESP &&
232 	    is_broadcast_ether_addr(da))
233 		return true;
234 	if (scan_flags & NL80211_SCAN_FLAG_RANDOM_ADDR)
235 		return true;
236 	return ether_addr_equal(da, sdata->vif.addr);
237 }
238 
239 void ieee80211_scan_rx(struct ieee80211_local *local, struct sk_buff *skb)
240 {
241 	struct ieee80211_rx_status *rx_status = IEEE80211_SKB_RXCB(skb);
242 	struct ieee80211_sub_if_data *sdata1, *sdata2;
243 	struct ieee80211_mgmt *mgmt = (void *)skb->data;
244 	struct ieee80211_bss *bss;
245 	struct ieee80211_channel *channel;
246 
247 	if (skb->len < 24 ||
248 	    (!ieee80211_is_probe_resp(mgmt->frame_control) &&
249 	     !ieee80211_is_beacon(mgmt->frame_control)))
250 		return;
251 
252 	sdata1 = rcu_dereference(local->scan_sdata);
253 	sdata2 = rcu_dereference(local->sched_scan_sdata);
254 
255 	if (likely(!sdata1 && !sdata2))
256 		return;
257 
258 	if (ieee80211_is_probe_resp(mgmt->frame_control)) {
259 		struct cfg80211_scan_request *scan_req;
260 		struct cfg80211_sched_scan_request *sched_scan_req;
261 		u32 scan_req_flags = 0, sched_scan_req_flags = 0;
262 
263 		scan_req = rcu_dereference(local->scan_req);
264 		sched_scan_req = rcu_dereference(local->sched_scan_req);
265 
266 		if (scan_req)
267 			scan_req_flags = scan_req->flags;
268 
269 		if (sched_scan_req)
270 			sched_scan_req_flags = sched_scan_req->flags;
271 
272 		/* ignore ProbeResp to foreign address or non-bcast (OCE)
273 		 * unless scanning with randomised address
274 		 */
275 		if (!ieee80211_scan_accept_presp(sdata1, scan_req_flags,
276 						 mgmt->da) &&
277 		    !ieee80211_scan_accept_presp(sdata2, sched_scan_req_flags,
278 						 mgmt->da))
279 			return;
280 	}
281 
282 	channel = ieee80211_get_channel(local->hw.wiphy, rx_status->freq);
283 
284 	if (!channel || channel->flags & IEEE80211_CHAN_DISABLED)
285 		return;
286 
287 	bss = ieee80211_bss_info_update(local, rx_status,
288 					mgmt, skb->len,
289 					channel);
290 	if (bss)
291 		ieee80211_rx_bss_put(local, bss);
292 }
293 
294 static void
295 ieee80211_prepare_scan_chandef(struct cfg80211_chan_def *chandef,
296 			       enum nl80211_bss_scan_width scan_width)
297 {
298 	memset(chandef, 0, sizeof(*chandef));
299 	switch (scan_width) {
300 	case NL80211_BSS_CHAN_WIDTH_5:
301 		chandef->width = NL80211_CHAN_WIDTH_5;
302 		break;
303 	case NL80211_BSS_CHAN_WIDTH_10:
304 		chandef->width = NL80211_CHAN_WIDTH_10;
305 		break;
306 	default:
307 		chandef->width = NL80211_CHAN_WIDTH_20_NOHT;
308 		break;
309 	}
310 }
311 
312 /* return false if no more work */
313 static bool ieee80211_prep_hw_scan(struct ieee80211_local *local)
314 {
315 	struct cfg80211_scan_request *req;
316 	struct cfg80211_chan_def chandef;
317 	u8 bands_used = 0;
318 	int i, ielen, n_chans;
319 	u32 flags = 0;
320 
321 	req = rcu_dereference_protected(local->scan_req,
322 					lockdep_is_held(&local->mtx));
323 
324 	if (test_bit(SCAN_HW_CANCELLED, &local->scanning))
325 		return false;
326 
327 	if (ieee80211_hw_check(&local->hw, SINGLE_SCAN_ON_ALL_BANDS)) {
328 		for (i = 0; i < req->n_channels; i++) {
329 			local->hw_scan_req->req.channels[i] = req->channels[i];
330 			bands_used |= BIT(req->channels[i]->band);
331 		}
332 
333 		n_chans = req->n_channels;
334 	} else {
335 		do {
336 			if (local->hw_scan_band == NUM_NL80211_BANDS)
337 				return false;
338 
339 			n_chans = 0;
340 
341 			for (i = 0; i < req->n_channels; i++) {
342 				if (req->channels[i]->band !=
343 				    local->hw_scan_band)
344 					continue;
345 				local->hw_scan_req->req.channels[n_chans] =
346 							req->channels[i];
347 				n_chans++;
348 				bands_used |= BIT(req->channels[i]->band);
349 			}
350 
351 			local->hw_scan_band++;
352 		} while (!n_chans);
353 	}
354 
355 	local->hw_scan_req->req.n_channels = n_chans;
356 	ieee80211_prepare_scan_chandef(&chandef, req->scan_width);
357 
358 	if (req->flags & NL80211_SCAN_FLAG_MIN_PREQ_CONTENT)
359 		flags |= IEEE80211_PROBE_FLAG_MIN_CONTENT;
360 
361 	ielen = ieee80211_build_preq_ies(local,
362 					 (u8 *)local->hw_scan_req->req.ie,
363 					 local->hw_scan_ies_bufsize,
364 					 &local->hw_scan_req->ies,
365 					 req->ie, req->ie_len,
366 					 bands_used, req->rates, &chandef,
367 					 flags);
368 	local->hw_scan_req->req.ie_len = ielen;
369 	local->hw_scan_req->req.no_cck = req->no_cck;
370 	ether_addr_copy(local->hw_scan_req->req.mac_addr, req->mac_addr);
371 	ether_addr_copy(local->hw_scan_req->req.mac_addr_mask,
372 			req->mac_addr_mask);
373 	ether_addr_copy(local->hw_scan_req->req.bssid, req->bssid);
374 
375 	return true;
376 }
377 
378 static void __ieee80211_scan_completed(struct ieee80211_hw *hw, bool aborted)
379 {
380 	struct ieee80211_local *local = hw_to_local(hw);
381 	bool hw_scan = test_bit(SCAN_HW_SCANNING, &local->scanning);
382 	bool was_scanning = local->scanning;
383 	struct cfg80211_scan_request *scan_req;
384 	struct ieee80211_sub_if_data *scan_sdata;
385 	struct ieee80211_sub_if_data *sdata;
386 
387 	lockdep_assert_held(&local->mtx);
388 
389 	/*
390 	 * It's ok to abort a not-yet-running scan (that
391 	 * we have one at all will be verified by checking
392 	 * local->scan_req next), but not to complete it
393 	 * successfully.
394 	 */
395 	if (WARN_ON(!local->scanning && !aborted))
396 		aborted = true;
397 
398 	if (WARN_ON(!local->scan_req))
399 		return;
400 
401 	if (hw_scan && !aborted &&
402 	    !ieee80211_hw_check(&local->hw, SINGLE_SCAN_ON_ALL_BANDS) &&
403 	    ieee80211_prep_hw_scan(local)) {
404 		int rc;
405 
406 		rc = drv_hw_scan(local,
407 			rcu_dereference_protected(local->scan_sdata,
408 						  lockdep_is_held(&local->mtx)),
409 			local->hw_scan_req);
410 
411 		if (rc == 0)
412 			return;
413 
414 		/* HW scan failed and is going to be reported as aborted,
415 		 * so clear old scan info.
416 		 */
417 		memset(&local->scan_info, 0, sizeof(local->scan_info));
418 		aborted = true;
419 	}
420 
421 	kfree(local->hw_scan_req);
422 	local->hw_scan_req = NULL;
423 
424 	scan_req = rcu_dereference_protected(local->scan_req,
425 					     lockdep_is_held(&local->mtx));
426 
427 	if (scan_req != local->int_scan_req) {
428 		local->scan_info.aborted = aborted;
429 		cfg80211_scan_done(scan_req, &local->scan_info);
430 	}
431 	RCU_INIT_POINTER(local->scan_req, NULL);
432 
433 	scan_sdata = rcu_dereference_protected(local->scan_sdata,
434 					       lockdep_is_held(&local->mtx));
435 	RCU_INIT_POINTER(local->scan_sdata, NULL);
436 
437 	local->scanning = 0;
438 	local->scan_chandef.chan = NULL;
439 
440 	/* Set power back to normal operating levels. */
441 	ieee80211_hw_config(local, 0);
442 
443 	if (!hw_scan) {
444 		ieee80211_configure_filter(local);
445 		drv_sw_scan_complete(local, scan_sdata);
446 		ieee80211_offchannel_return(local);
447 	}
448 
449 	ieee80211_recalc_idle(local);
450 
451 	ieee80211_mlme_notify_scan_completed(local);
452 	ieee80211_ibss_notify_scan_completed(local);
453 
454 	/* Requeue all the work that might have been ignored while
455 	 * the scan was in progress; if there was none this will
456 	 * just be a no-op for the particular interface.
457 	 */
458 	list_for_each_entry_rcu(sdata, &local->interfaces, list) {
459 		if (ieee80211_sdata_running(sdata))
460 			ieee80211_queue_work(&sdata->local->hw, &sdata->work);
461 	}
462 
463 	if (was_scanning)
464 		ieee80211_start_next_roc(local);
465 }
466 
467 void ieee80211_scan_completed(struct ieee80211_hw *hw,
468 			      struct cfg80211_scan_info *info)
469 {
470 	struct ieee80211_local *local = hw_to_local(hw);
471 
472 	trace_api_scan_completed(local, info->aborted);
473 
474 	set_bit(SCAN_COMPLETED, &local->scanning);
475 	if (info->aborted)
476 		set_bit(SCAN_ABORTED, &local->scanning);
477 
478 	memcpy(&local->scan_info, info, sizeof(*info));
479 
480 	ieee80211_queue_delayed_work(&local->hw, &local->scan_work, 0);
481 }
482 EXPORT_SYMBOL(ieee80211_scan_completed);
483 
484 static int ieee80211_start_sw_scan(struct ieee80211_local *local,
485 				   struct ieee80211_sub_if_data *sdata)
486 {
487 	/* Software scan is not supported in multi-channel cases */
488 	if (local->use_chanctx)
489 		return -EOPNOTSUPP;
490 
491 	/*
492 	 * Hardware/driver doesn't support hw_scan, so use software
493 	 * scanning instead. First send a nullfunc frame with power save
494 	 * bit on so that AP will buffer the frames for us while we are not
495 	 * listening, then send probe requests to each channel and wait for
496 	 * the responses. After all channels are scanned, tune back to the
497 	 * original channel and send a nullfunc frame with power save bit
498 	 * off to trigger the AP to send us all the buffered frames.
499 	 *
500 	 * Note that while local->sw_scanning is true everything else but
501 	 * nullfunc frames and probe requests will be dropped in
502 	 * ieee80211_tx_h_check_assoc().
503 	 */
504 	drv_sw_scan_start(local, sdata, local->scan_addr);
505 
506 	local->leave_oper_channel_time = jiffies;
507 	local->next_scan_state = SCAN_DECISION;
508 	local->scan_channel_idx = 0;
509 
510 	ieee80211_offchannel_stop_vifs(local);
511 
512 	/* ensure nullfunc is transmitted before leaving operating channel */
513 	ieee80211_flush_queues(local, NULL, false);
514 
515 	ieee80211_configure_filter(local);
516 
517 	/* We need to set power level at maximum rate for scanning. */
518 	ieee80211_hw_config(local, 0);
519 
520 	ieee80211_queue_delayed_work(&local->hw,
521 				     &local->scan_work, 0);
522 
523 	return 0;
524 }
525 
526 static bool ieee80211_can_scan(struct ieee80211_local *local,
527 			       struct ieee80211_sub_if_data *sdata)
528 {
529 	if (ieee80211_is_radar_required(local))
530 		return false;
531 
532 	if (!list_empty(&local->roc_list))
533 		return false;
534 
535 	if (sdata->vif.type == NL80211_IFTYPE_STATION &&
536 	    sdata->u.mgd.flags & IEEE80211_STA_CONNECTION_POLL)
537 		return false;
538 
539 	return true;
540 }
541 
542 void ieee80211_run_deferred_scan(struct ieee80211_local *local)
543 {
544 	lockdep_assert_held(&local->mtx);
545 
546 	if (!local->scan_req || local->scanning)
547 		return;
548 
549 	if (!ieee80211_can_scan(local,
550 				rcu_dereference_protected(
551 					local->scan_sdata,
552 					lockdep_is_held(&local->mtx))))
553 		return;
554 
555 	ieee80211_queue_delayed_work(&local->hw, &local->scan_work,
556 				     round_jiffies_relative(0));
557 }
558 
559 static void ieee80211_send_scan_probe_req(struct ieee80211_sub_if_data *sdata,
560 					  const u8 *src, const u8 *dst,
561 					  const u8 *ssid, size_t ssid_len,
562 					  const u8 *ie, size_t ie_len,
563 					  u32 ratemask, u32 flags, u32 tx_flags,
564 					  struct ieee80211_channel *channel)
565 {
566 	struct sk_buff *skb;
567 	u32 txdata_flags = 0;
568 
569 	skb = ieee80211_build_probe_req(sdata, src, dst, ratemask, channel,
570 					ssid, ssid_len,
571 					ie, ie_len, flags);
572 
573 	if (skb) {
574 		if (flags & IEEE80211_PROBE_FLAG_RANDOM_SN) {
575 			struct ieee80211_hdr *hdr = (void *)skb->data;
576 			u16 sn = get_random_u32();
577 
578 			txdata_flags |= IEEE80211_TX_NO_SEQNO;
579 			hdr->seq_ctrl =
580 				cpu_to_le16(IEEE80211_SN_TO_SEQ(sn));
581 		}
582 		IEEE80211_SKB_CB(skb)->flags |= tx_flags;
583 		ieee80211_tx_skb_tid_band(sdata, skb, 7, channel->band,
584 					  txdata_flags);
585 	}
586 }
587 
588 static void ieee80211_scan_state_send_probe(struct ieee80211_local *local,
589 					    unsigned long *next_delay)
590 {
591 	int i;
592 	struct ieee80211_sub_if_data *sdata;
593 	struct cfg80211_scan_request *scan_req;
594 	enum nl80211_band band = local->hw.conf.chandef.chan->band;
595 	u32 flags = 0, tx_flags;
596 
597 	scan_req = rcu_dereference_protected(local->scan_req,
598 					     lockdep_is_held(&local->mtx));
599 
600 	tx_flags = IEEE80211_TX_INTFL_OFFCHAN_TX_OK;
601 	if (scan_req->no_cck)
602 		tx_flags |= IEEE80211_TX_CTL_NO_CCK_RATE;
603 	if (scan_req->flags & NL80211_SCAN_FLAG_MIN_PREQ_CONTENT)
604 		flags |= IEEE80211_PROBE_FLAG_MIN_CONTENT;
605 	if (scan_req->flags & NL80211_SCAN_FLAG_RANDOM_SN)
606 		flags |= IEEE80211_PROBE_FLAG_RANDOM_SN;
607 
608 	sdata = rcu_dereference_protected(local->scan_sdata,
609 					  lockdep_is_held(&local->mtx));
610 
611 	for (i = 0; i < scan_req->n_ssids; i++)
612 		ieee80211_send_scan_probe_req(
613 			sdata, local->scan_addr, scan_req->bssid,
614 			scan_req->ssids[i].ssid, scan_req->ssids[i].ssid_len,
615 			scan_req->ie, scan_req->ie_len,
616 			scan_req->rates[band], flags,
617 			tx_flags, local->hw.conf.chandef.chan);
618 
619 	/*
620 	 * After sending probe requests, wait for probe responses
621 	 * on the channel.
622 	 */
623 	*next_delay = IEEE80211_CHANNEL_TIME;
624 	local->next_scan_state = SCAN_DECISION;
625 }
626 
627 static int __ieee80211_start_scan(struct ieee80211_sub_if_data *sdata,
628 				  struct cfg80211_scan_request *req)
629 {
630 	struct ieee80211_local *local = sdata->local;
631 	bool hw_scan = local->ops->hw_scan;
632 	int rc;
633 
634 	lockdep_assert_held(&local->mtx);
635 
636 	if (local->scan_req || ieee80211_is_radar_required(local))
637 		return -EBUSY;
638 
639 	if (!ieee80211_can_scan(local, sdata)) {
640 		/* wait for the work to finish/time out */
641 		rcu_assign_pointer(local->scan_req, req);
642 		rcu_assign_pointer(local->scan_sdata, sdata);
643 		return 0;
644 	}
645 
646  again:
647 	if (hw_scan) {
648 		u8 *ies;
649 
650 		local->hw_scan_ies_bufsize = local->scan_ies_len + req->ie_len;
651 
652 		if (ieee80211_hw_check(&local->hw, SINGLE_SCAN_ON_ALL_BANDS)) {
653 			int i, n_bands = 0;
654 			u8 bands_counted = 0;
655 
656 			for (i = 0; i < req->n_channels; i++) {
657 				if (bands_counted & BIT(req->channels[i]->band))
658 					continue;
659 				bands_counted |= BIT(req->channels[i]->band);
660 				n_bands++;
661 			}
662 
663 			local->hw_scan_ies_bufsize *= n_bands;
664 		}
665 
666 		local->hw_scan_req = kmalloc(
667 				sizeof(*local->hw_scan_req) +
668 				req->n_channels * sizeof(req->channels[0]) +
669 				local->hw_scan_ies_bufsize, GFP_KERNEL);
670 		if (!local->hw_scan_req)
671 			return -ENOMEM;
672 
673 		local->hw_scan_req->req.ssids = req->ssids;
674 		local->hw_scan_req->req.n_ssids = req->n_ssids;
675 		ies = (u8 *)local->hw_scan_req +
676 			sizeof(*local->hw_scan_req) +
677 			req->n_channels * sizeof(req->channels[0]);
678 		local->hw_scan_req->req.ie = ies;
679 		local->hw_scan_req->req.flags = req->flags;
680 		eth_broadcast_addr(local->hw_scan_req->req.bssid);
681 		local->hw_scan_req->req.duration = req->duration;
682 		local->hw_scan_req->req.duration_mandatory =
683 			req->duration_mandatory;
684 
685 		local->hw_scan_band = 0;
686 
687 		/*
688 		 * After allocating local->hw_scan_req, we must
689 		 * go through until ieee80211_prep_hw_scan(), so
690 		 * anything that might be changed here and leave
691 		 * this function early must not go after this
692 		 * allocation.
693 		 */
694 	}
695 
696 	rcu_assign_pointer(local->scan_req, req);
697 	rcu_assign_pointer(local->scan_sdata, sdata);
698 
699 	if (req->flags & NL80211_SCAN_FLAG_RANDOM_ADDR)
700 		get_random_mask_addr(local->scan_addr,
701 				     req->mac_addr,
702 				     req->mac_addr_mask);
703 	else
704 		memcpy(local->scan_addr, sdata->vif.addr, ETH_ALEN);
705 
706 	if (hw_scan) {
707 		__set_bit(SCAN_HW_SCANNING, &local->scanning);
708 	} else if ((req->n_channels == 1) &&
709 		   (req->channels[0] == local->_oper_chandef.chan)) {
710 		/*
711 		 * If we are scanning only on the operating channel
712 		 * then we do not need to stop normal activities
713 		 */
714 		unsigned long next_delay;
715 
716 		__set_bit(SCAN_ONCHANNEL_SCANNING, &local->scanning);
717 
718 		ieee80211_recalc_idle(local);
719 
720 		/* Notify driver scan is starting, keep order of operations
721 		 * same as normal software scan, in case that matters. */
722 		drv_sw_scan_start(local, sdata, local->scan_addr);
723 
724 		ieee80211_configure_filter(local); /* accept probe-responses */
725 
726 		/* We need to ensure power level is at max for scanning. */
727 		ieee80211_hw_config(local, 0);
728 
729 		if ((req->channels[0]->flags & (IEEE80211_CHAN_NO_IR |
730 						IEEE80211_CHAN_RADAR)) ||
731 		    !req->n_ssids) {
732 			next_delay = IEEE80211_PASSIVE_CHANNEL_TIME;
733 		} else {
734 			ieee80211_scan_state_send_probe(local, &next_delay);
735 			next_delay = IEEE80211_CHANNEL_TIME;
736 		}
737 
738 		/* Now, just wait a bit and we are all done! */
739 		ieee80211_queue_delayed_work(&local->hw, &local->scan_work,
740 					     next_delay);
741 		return 0;
742 	} else {
743 		/* Do normal software scan */
744 		__set_bit(SCAN_SW_SCANNING, &local->scanning);
745 	}
746 
747 	ieee80211_recalc_idle(local);
748 
749 	if (hw_scan) {
750 		WARN_ON(!ieee80211_prep_hw_scan(local));
751 		rc = drv_hw_scan(local, sdata, local->hw_scan_req);
752 	} else {
753 		rc = ieee80211_start_sw_scan(local, sdata);
754 	}
755 
756 	if (rc) {
757 		kfree(local->hw_scan_req);
758 		local->hw_scan_req = NULL;
759 		local->scanning = 0;
760 
761 		ieee80211_recalc_idle(local);
762 
763 		local->scan_req = NULL;
764 		RCU_INIT_POINTER(local->scan_sdata, NULL);
765 	}
766 
767 	if (hw_scan && rc == 1) {
768 		/*
769 		 * we can't fall back to software for P2P-GO
770 		 * as it must update NoA etc.
771 		 */
772 		if (ieee80211_vif_type_p2p(&sdata->vif) ==
773 				NL80211_IFTYPE_P2P_GO)
774 			return -EOPNOTSUPP;
775 		hw_scan = false;
776 		goto again;
777 	}
778 
779 	return rc;
780 }
781 
782 static unsigned long
783 ieee80211_scan_get_channel_time(struct ieee80211_channel *chan)
784 {
785 	/*
786 	 * TODO: channel switching also consumes quite some time,
787 	 * add that delay as well to get a better estimation
788 	 */
789 	if (chan->flags & (IEEE80211_CHAN_NO_IR | IEEE80211_CHAN_RADAR))
790 		return IEEE80211_PASSIVE_CHANNEL_TIME;
791 	return IEEE80211_PROBE_DELAY + IEEE80211_CHANNEL_TIME;
792 }
793 
794 static void ieee80211_scan_state_decision(struct ieee80211_local *local,
795 					  unsigned long *next_delay)
796 {
797 	bool associated = false;
798 	bool tx_empty = true;
799 	bool bad_latency;
800 	struct ieee80211_sub_if_data *sdata;
801 	struct ieee80211_channel *next_chan;
802 	enum mac80211_scan_state next_scan_state;
803 	struct cfg80211_scan_request *scan_req;
804 
805 	/*
806 	 * check if at least one STA interface is associated,
807 	 * check if at least one STA interface has pending tx frames
808 	 * and grab the lowest used beacon interval
809 	 */
810 	mutex_lock(&local->iflist_mtx);
811 	list_for_each_entry(sdata, &local->interfaces, list) {
812 		if (!ieee80211_sdata_running(sdata))
813 			continue;
814 
815 		if (sdata->vif.type == NL80211_IFTYPE_STATION) {
816 			if (sdata->u.mgd.associated) {
817 				associated = true;
818 
819 				if (!qdisc_all_tx_empty(sdata->dev)) {
820 					tx_empty = false;
821 					break;
822 				}
823 			}
824 		}
825 	}
826 	mutex_unlock(&local->iflist_mtx);
827 
828 	scan_req = rcu_dereference_protected(local->scan_req,
829 					     lockdep_is_held(&local->mtx));
830 
831 	next_chan = scan_req->channels[local->scan_channel_idx];
832 
833 	/*
834 	 * we're currently scanning a different channel, let's
835 	 * see if we can scan another channel without interfering
836 	 * with the current traffic situation.
837 	 *
838 	 * Keep good latency, do not stay off-channel more than 125 ms.
839 	 */
840 
841 	bad_latency = time_after(jiffies +
842 				 ieee80211_scan_get_channel_time(next_chan),
843 				 local->leave_oper_channel_time + HZ / 8);
844 
845 	if (associated && !tx_empty) {
846 		if (scan_req->flags & NL80211_SCAN_FLAG_LOW_PRIORITY)
847 			next_scan_state = SCAN_ABORT;
848 		else
849 			next_scan_state = SCAN_SUSPEND;
850 	} else if (associated && bad_latency) {
851 		next_scan_state = SCAN_SUSPEND;
852 	} else {
853 		next_scan_state = SCAN_SET_CHANNEL;
854 	}
855 
856 	local->next_scan_state = next_scan_state;
857 
858 	*next_delay = 0;
859 }
860 
861 static void ieee80211_scan_state_set_channel(struct ieee80211_local *local,
862 					     unsigned long *next_delay)
863 {
864 	int skip;
865 	struct ieee80211_channel *chan;
866 	enum nl80211_bss_scan_width oper_scan_width;
867 	struct cfg80211_scan_request *scan_req;
868 
869 	scan_req = rcu_dereference_protected(local->scan_req,
870 					     lockdep_is_held(&local->mtx));
871 
872 	skip = 0;
873 	chan = scan_req->channels[local->scan_channel_idx];
874 
875 	local->scan_chandef.chan = chan;
876 	local->scan_chandef.center_freq1 = chan->center_freq;
877 	local->scan_chandef.center_freq2 = 0;
878 	switch (scan_req->scan_width) {
879 	case NL80211_BSS_CHAN_WIDTH_5:
880 		local->scan_chandef.width = NL80211_CHAN_WIDTH_5;
881 		break;
882 	case NL80211_BSS_CHAN_WIDTH_10:
883 		local->scan_chandef.width = NL80211_CHAN_WIDTH_10;
884 		break;
885 	case NL80211_BSS_CHAN_WIDTH_20:
886 		/* If scanning on oper channel, use whatever channel-type
887 		 * is currently in use.
888 		 */
889 		oper_scan_width = cfg80211_chandef_to_scan_width(
890 					&local->_oper_chandef);
891 		if (chan == local->_oper_chandef.chan &&
892 		    oper_scan_width == scan_req->scan_width)
893 			local->scan_chandef = local->_oper_chandef;
894 		else
895 			local->scan_chandef.width = NL80211_CHAN_WIDTH_20_NOHT;
896 		break;
897 	}
898 
899 	if (ieee80211_hw_config(local, IEEE80211_CONF_CHANGE_CHANNEL))
900 		skip = 1;
901 
902 	/* advance state machine to next channel/band */
903 	local->scan_channel_idx++;
904 
905 	if (skip) {
906 		/* if we skip this channel return to the decision state */
907 		local->next_scan_state = SCAN_DECISION;
908 		return;
909 	}
910 
911 	/*
912 	 * Probe delay is used to update the NAV, cf. 11.1.3.2.2
913 	 * (which unfortunately doesn't say _why_ step a) is done,
914 	 * but it waits for the probe delay or until a frame is
915 	 * received - and the received frame would update the NAV).
916 	 * For now, we do not support waiting until a frame is
917 	 * received.
918 	 *
919 	 * In any case, it is not necessary for a passive scan.
920 	 */
921 	if ((chan->flags & (IEEE80211_CHAN_NO_IR | IEEE80211_CHAN_RADAR)) ||
922 	    !scan_req->n_ssids) {
923 		*next_delay = IEEE80211_PASSIVE_CHANNEL_TIME;
924 		local->next_scan_state = SCAN_DECISION;
925 		return;
926 	}
927 
928 	/* active scan, send probes */
929 	*next_delay = IEEE80211_PROBE_DELAY;
930 	local->next_scan_state = SCAN_SEND_PROBE;
931 }
932 
933 static void ieee80211_scan_state_suspend(struct ieee80211_local *local,
934 					 unsigned long *next_delay)
935 {
936 	/* switch back to the operating channel */
937 	local->scan_chandef.chan = NULL;
938 	ieee80211_hw_config(local, IEEE80211_CONF_CHANGE_CHANNEL);
939 
940 	/* disable PS */
941 	ieee80211_offchannel_return(local);
942 
943 	*next_delay = HZ / 5;
944 	/* afterwards, resume scan & go to next channel */
945 	local->next_scan_state = SCAN_RESUME;
946 }
947 
948 static void ieee80211_scan_state_resume(struct ieee80211_local *local,
949 					unsigned long *next_delay)
950 {
951 	ieee80211_offchannel_stop_vifs(local);
952 
953 	if (local->ops->flush) {
954 		ieee80211_flush_queues(local, NULL, false);
955 		*next_delay = 0;
956 	} else
957 		*next_delay = HZ / 10;
958 
959 	/* remember when we left the operating channel */
960 	local->leave_oper_channel_time = jiffies;
961 
962 	/* advance to the next channel to be scanned */
963 	local->next_scan_state = SCAN_SET_CHANNEL;
964 }
965 
966 void ieee80211_scan_work(struct work_struct *work)
967 {
968 	struct ieee80211_local *local =
969 		container_of(work, struct ieee80211_local, scan_work.work);
970 	struct ieee80211_sub_if_data *sdata;
971 	struct cfg80211_scan_request *scan_req;
972 	unsigned long next_delay = 0;
973 	bool aborted;
974 
975 	mutex_lock(&local->mtx);
976 
977 	if (!ieee80211_can_run_worker(local)) {
978 		aborted = true;
979 		goto out_complete;
980 	}
981 
982 	sdata = rcu_dereference_protected(local->scan_sdata,
983 					  lockdep_is_held(&local->mtx));
984 	scan_req = rcu_dereference_protected(local->scan_req,
985 					     lockdep_is_held(&local->mtx));
986 
987 	/* When scanning on-channel, the first-callback means completed. */
988 	if (test_bit(SCAN_ONCHANNEL_SCANNING, &local->scanning)) {
989 		aborted = test_and_clear_bit(SCAN_ABORTED, &local->scanning);
990 		goto out_complete;
991 	}
992 
993 	if (test_and_clear_bit(SCAN_COMPLETED, &local->scanning)) {
994 		aborted = test_and_clear_bit(SCAN_ABORTED, &local->scanning);
995 		goto out_complete;
996 	}
997 
998 	if (!sdata || !scan_req)
999 		goto out;
1000 
1001 	if (!local->scanning) {
1002 		int rc;
1003 
1004 		RCU_INIT_POINTER(local->scan_req, NULL);
1005 		RCU_INIT_POINTER(local->scan_sdata, NULL);
1006 
1007 		rc = __ieee80211_start_scan(sdata, scan_req);
1008 		if (rc) {
1009 			/* need to complete scan in cfg80211 */
1010 			rcu_assign_pointer(local->scan_req, scan_req);
1011 			aborted = true;
1012 			goto out_complete;
1013 		} else
1014 			goto out;
1015 	}
1016 
1017 	/*
1018 	 * as long as no delay is required advance immediately
1019 	 * without scheduling a new work
1020 	 */
1021 	do {
1022 		if (!ieee80211_sdata_running(sdata)) {
1023 			aborted = true;
1024 			goto out_complete;
1025 		}
1026 
1027 		switch (local->next_scan_state) {
1028 		case SCAN_DECISION:
1029 			/* if no more bands/channels left, complete scan */
1030 			if (local->scan_channel_idx >= scan_req->n_channels) {
1031 				aborted = false;
1032 				goto out_complete;
1033 			}
1034 			ieee80211_scan_state_decision(local, &next_delay);
1035 			break;
1036 		case SCAN_SET_CHANNEL:
1037 			ieee80211_scan_state_set_channel(local, &next_delay);
1038 			break;
1039 		case SCAN_SEND_PROBE:
1040 			ieee80211_scan_state_send_probe(local, &next_delay);
1041 			break;
1042 		case SCAN_SUSPEND:
1043 			ieee80211_scan_state_suspend(local, &next_delay);
1044 			break;
1045 		case SCAN_RESUME:
1046 			ieee80211_scan_state_resume(local, &next_delay);
1047 			break;
1048 		case SCAN_ABORT:
1049 			aborted = true;
1050 			goto out_complete;
1051 		}
1052 	} while (next_delay == 0);
1053 
1054 	ieee80211_queue_delayed_work(&local->hw, &local->scan_work, next_delay);
1055 	goto out;
1056 
1057 out_complete:
1058 	__ieee80211_scan_completed(&local->hw, aborted);
1059 out:
1060 	mutex_unlock(&local->mtx);
1061 }
1062 
1063 int ieee80211_request_scan(struct ieee80211_sub_if_data *sdata,
1064 			   struct cfg80211_scan_request *req)
1065 {
1066 	int res;
1067 
1068 	mutex_lock(&sdata->local->mtx);
1069 	res = __ieee80211_start_scan(sdata, req);
1070 	mutex_unlock(&sdata->local->mtx);
1071 
1072 	return res;
1073 }
1074 
1075 int ieee80211_request_ibss_scan(struct ieee80211_sub_if_data *sdata,
1076 				const u8 *ssid, u8 ssid_len,
1077 				struct ieee80211_channel **channels,
1078 				unsigned int n_channels,
1079 				enum nl80211_bss_scan_width scan_width)
1080 {
1081 	struct ieee80211_local *local = sdata->local;
1082 	int ret = -EBUSY, i, n_ch = 0;
1083 	enum nl80211_band band;
1084 
1085 	mutex_lock(&local->mtx);
1086 
1087 	/* busy scanning */
1088 	if (local->scan_req)
1089 		goto unlock;
1090 
1091 	/* fill internal scan request */
1092 	if (!channels) {
1093 		int max_n;
1094 
1095 		for (band = 0; band < NUM_NL80211_BANDS; band++) {
1096 			if (!local->hw.wiphy->bands[band])
1097 				continue;
1098 
1099 			max_n = local->hw.wiphy->bands[band]->n_channels;
1100 			for (i = 0; i < max_n; i++) {
1101 				struct ieee80211_channel *tmp_ch =
1102 				    &local->hw.wiphy->bands[band]->channels[i];
1103 
1104 				if (tmp_ch->flags & (IEEE80211_CHAN_NO_IR |
1105 						     IEEE80211_CHAN_DISABLED))
1106 					continue;
1107 
1108 				local->int_scan_req->channels[n_ch] = tmp_ch;
1109 				n_ch++;
1110 			}
1111 		}
1112 
1113 		if (WARN_ON_ONCE(n_ch == 0))
1114 			goto unlock;
1115 
1116 		local->int_scan_req->n_channels = n_ch;
1117 	} else {
1118 		for (i = 0; i < n_channels; i++) {
1119 			if (channels[i]->flags & (IEEE80211_CHAN_NO_IR |
1120 						  IEEE80211_CHAN_DISABLED))
1121 				continue;
1122 
1123 			local->int_scan_req->channels[n_ch] = channels[i];
1124 			n_ch++;
1125 		}
1126 
1127 		if (WARN_ON_ONCE(n_ch == 0))
1128 			goto unlock;
1129 
1130 		local->int_scan_req->n_channels = n_ch;
1131 	}
1132 
1133 	local->int_scan_req->ssids = &local->scan_ssid;
1134 	local->int_scan_req->n_ssids = 1;
1135 	local->int_scan_req->scan_width = scan_width;
1136 	memcpy(local->int_scan_req->ssids[0].ssid, ssid, IEEE80211_MAX_SSID_LEN);
1137 	local->int_scan_req->ssids[0].ssid_len = ssid_len;
1138 
1139 	ret = __ieee80211_start_scan(sdata, sdata->local->int_scan_req);
1140  unlock:
1141 	mutex_unlock(&local->mtx);
1142 	return ret;
1143 }
1144 
1145 /*
1146  * Only call this function when a scan can't be queued -- under RTNL.
1147  */
1148 void ieee80211_scan_cancel(struct ieee80211_local *local)
1149 {
1150 	/*
1151 	 * We are canceling software scan, or deferred scan that was not
1152 	 * yet really started (see __ieee80211_start_scan ).
1153 	 *
1154 	 * Regarding hardware scan:
1155 	 * - we can not call  __ieee80211_scan_completed() as when
1156 	 *   SCAN_HW_SCANNING bit is set this function change
1157 	 *   local->hw_scan_req to operate on 5G band, what race with
1158 	 *   driver which can use local->hw_scan_req
1159 	 *
1160 	 * - we can not cancel scan_work since driver can schedule it
1161 	 *   by ieee80211_scan_completed(..., true) to finish scan
1162 	 *
1163 	 * Hence we only call the cancel_hw_scan() callback, but the low-level
1164 	 * driver is still responsible for calling ieee80211_scan_completed()
1165 	 * after the scan was completed/aborted.
1166 	 */
1167 
1168 	mutex_lock(&local->mtx);
1169 	if (!local->scan_req)
1170 		goto out;
1171 
1172 	/*
1173 	 * We have a scan running and the driver already reported completion,
1174 	 * but the worker hasn't run yet or is stuck on the mutex - mark it as
1175 	 * cancelled.
1176 	 */
1177 	if (test_bit(SCAN_HW_SCANNING, &local->scanning) &&
1178 	    test_bit(SCAN_COMPLETED, &local->scanning)) {
1179 		set_bit(SCAN_HW_CANCELLED, &local->scanning);
1180 		goto out;
1181 	}
1182 
1183 	if (test_bit(SCAN_HW_SCANNING, &local->scanning)) {
1184 		/*
1185 		 * Make sure that __ieee80211_scan_completed doesn't trigger a
1186 		 * scan on another band.
1187 		 */
1188 		set_bit(SCAN_HW_CANCELLED, &local->scanning);
1189 		if (local->ops->cancel_hw_scan)
1190 			drv_cancel_hw_scan(local,
1191 				rcu_dereference_protected(local->scan_sdata,
1192 						lockdep_is_held(&local->mtx)));
1193 		goto out;
1194 	}
1195 
1196 	/*
1197 	 * If the work is currently running, it must be blocked on
1198 	 * the mutex, but we'll set scan_sdata = NULL and it'll
1199 	 * simply exit once it acquires the mutex.
1200 	 */
1201 	cancel_delayed_work(&local->scan_work);
1202 	/* and clean up */
1203 	memset(&local->scan_info, 0, sizeof(local->scan_info));
1204 	__ieee80211_scan_completed(&local->hw, true);
1205 out:
1206 	mutex_unlock(&local->mtx);
1207 }
1208 
1209 int __ieee80211_request_sched_scan_start(struct ieee80211_sub_if_data *sdata,
1210 					struct cfg80211_sched_scan_request *req)
1211 {
1212 	struct ieee80211_local *local = sdata->local;
1213 	struct ieee80211_scan_ies sched_scan_ies = {};
1214 	struct cfg80211_chan_def chandef;
1215 	int ret, i, iebufsz, num_bands = 0;
1216 	u32 rate_masks[NUM_NL80211_BANDS] = {};
1217 	u8 bands_used = 0;
1218 	u8 *ie;
1219 	u32 flags = 0;
1220 
1221 	iebufsz = local->scan_ies_len + req->ie_len;
1222 
1223 	lockdep_assert_held(&local->mtx);
1224 
1225 	if (!local->ops->sched_scan_start)
1226 		return -ENOTSUPP;
1227 
1228 	for (i = 0; i < NUM_NL80211_BANDS; i++) {
1229 		if (local->hw.wiphy->bands[i]) {
1230 			bands_used |= BIT(i);
1231 			rate_masks[i] = (u32) -1;
1232 			num_bands++;
1233 		}
1234 	}
1235 
1236 	if (req->flags & NL80211_SCAN_FLAG_MIN_PREQ_CONTENT)
1237 		flags |= IEEE80211_PROBE_FLAG_MIN_CONTENT;
1238 
1239 	ie = kcalloc(iebufsz, num_bands, GFP_KERNEL);
1240 	if (!ie) {
1241 		ret = -ENOMEM;
1242 		goto out;
1243 	}
1244 
1245 	ieee80211_prepare_scan_chandef(&chandef, req->scan_width);
1246 
1247 	ieee80211_build_preq_ies(local, ie, num_bands * iebufsz,
1248 				 &sched_scan_ies, req->ie,
1249 				 req->ie_len, bands_used, rate_masks, &chandef,
1250 				 flags);
1251 
1252 	ret = drv_sched_scan_start(local, sdata, req, &sched_scan_ies);
1253 	if (ret == 0) {
1254 		rcu_assign_pointer(local->sched_scan_sdata, sdata);
1255 		rcu_assign_pointer(local->sched_scan_req, req);
1256 	}
1257 
1258 	kfree(ie);
1259 
1260 out:
1261 	if (ret) {
1262 		/* Clean in case of failure after HW restart or upon resume. */
1263 		RCU_INIT_POINTER(local->sched_scan_sdata, NULL);
1264 		RCU_INIT_POINTER(local->sched_scan_req, NULL);
1265 	}
1266 
1267 	return ret;
1268 }
1269 
1270 int ieee80211_request_sched_scan_start(struct ieee80211_sub_if_data *sdata,
1271 				       struct cfg80211_sched_scan_request *req)
1272 {
1273 	struct ieee80211_local *local = sdata->local;
1274 	int ret;
1275 
1276 	mutex_lock(&local->mtx);
1277 
1278 	if (rcu_access_pointer(local->sched_scan_sdata)) {
1279 		mutex_unlock(&local->mtx);
1280 		return -EBUSY;
1281 	}
1282 
1283 	ret = __ieee80211_request_sched_scan_start(sdata, req);
1284 
1285 	mutex_unlock(&local->mtx);
1286 	return ret;
1287 }
1288 
1289 int ieee80211_request_sched_scan_stop(struct ieee80211_local *local)
1290 {
1291 	struct ieee80211_sub_if_data *sched_scan_sdata;
1292 	int ret = -ENOENT;
1293 
1294 	mutex_lock(&local->mtx);
1295 
1296 	if (!local->ops->sched_scan_stop) {
1297 		ret = -ENOTSUPP;
1298 		goto out;
1299 	}
1300 
1301 	/* We don't want to restart sched scan anymore. */
1302 	RCU_INIT_POINTER(local->sched_scan_req, NULL);
1303 
1304 	sched_scan_sdata = rcu_dereference_protected(local->sched_scan_sdata,
1305 						lockdep_is_held(&local->mtx));
1306 	if (sched_scan_sdata) {
1307 		ret = drv_sched_scan_stop(local, sched_scan_sdata);
1308 		if (!ret)
1309 			RCU_INIT_POINTER(local->sched_scan_sdata, NULL);
1310 	}
1311 out:
1312 	mutex_unlock(&local->mtx);
1313 
1314 	return ret;
1315 }
1316 
1317 void ieee80211_sched_scan_results(struct ieee80211_hw *hw)
1318 {
1319 	struct ieee80211_local *local = hw_to_local(hw);
1320 
1321 	trace_api_sched_scan_results(local);
1322 
1323 	cfg80211_sched_scan_results(hw->wiphy, 0);
1324 }
1325 EXPORT_SYMBOL(ieee80211_sched_scan_results);
1326 
1327 void ieee80211_sched_scan_end(struct ieee80211_local *local)
1328 {
1329 	mutex_lock(&local->mtx);
1330 
1331 	if (!rcu_access_pointer(local->sched_scan_sdata)) {
1332 		mutex_unlock(&local->mtx);
1333 		return;
1334 	}
1335 
1336 	RCU_INIT_POINTER(local->sched_scan_sdata, NULL);
1337 
1338 	/* If sched scan was aborted by the driver. */
1339 	RCU_INIT_POINTER(local->sched_scan_req, NULL);
1340 
1341 	mutex_unlock(&local->mtx);
1342 
1343 	cfg80211_sched_scan_stopped(local->hw.wiphy, 0);
1344 }
1345 
1346 void ieee80211_sched_scan_stopped_work(struct work_struct *work)
1347 {
1348 	struct ieee80211_local *local =
1349 		container_of(work, struct ieee80211_local,
1350 			     sched_scan_stopped_work);
1351 
1352 	ieee80211_sched_scan_end(local);
1353 }
1354 
1355 void ieee80211_sched_scan_stopped(struct ieee80211_hw *hw)
1356 {
1357 	struct ieee80211_local *local = hw_to_local(hw);
1358 
1359 	trace_api_sched_scan_stopped(local);
1360 
1361 	/*
1362 	 * this shouldn't really happen, so for simplicity
1363 	 * simply ignore it, and let mac80211 reconfigure
1364 	 * the sched scan later on.
1365 	 */
1366 	if (local->in_reconfig)
1367 		return;
1368 
1369 	schedule_work(&local->sched_scan_stopped_work);
1370 }
1371 EXPORT_SYMBOL(ieee80211_sched_scan_stopped);
1372