xref: /openbmc/linux/net/mac80211/scan.c (revision 1cac4f26)
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  *
12  * This program is free software; you can redistribute it and/or modify
13  * it under the terms of the GNU General Public License version 2 as
14  * published by the Free Software Foundation.
15  */
16 
17 #include <linux/if_arp.h>
18 #include <linux/etherdevice.h>
19 #include <linux/rtnetlink.h>
20 #include <net/sch_generic.h>
21 #include <linux/slab.h>
22 #include <linux/export.h>
23 #include <linux/random.h>
24 #include <net/mac80211.h>
25 
26 #include "ieee80211_i.h"
27 #include "driver-ops.h"
28 #include "mesh.h"
29 
30 #define IEEE80211_PROBE_DELAY (HZ / 33)
31 #define IEEE80211_CHANNEL_TIME (HZ / 33)
32 #define IEEE80211_PASSIVE_CHANNEL_TIME (HZ / 9)
33 
34 void ieee80211_rx_bss_put(struct ieee80211_local *local,
35 			  struct ieee80211_bss *bss)
36 {
37 	if (!bss)
38 		return;
39 	cfg80211_put_bss(local->hw.wiphy,
40 			 container_of((void *)bss, struct cfg80211_bss, priv));
41 }
42 
43 static bool is_uapsd_supported(struct ieee802_11_elems *elems)
44 {
45 	u8 qos_info;
46 
47 	if (elems->wmm_info && elems->wmm_info_len == 7
48 	    && elems->wmm_info[5] == 1)
49 		qos_info = elems->wmm_info[6];
50 	else if (elems->wmm_param && elems->wmm_param_len == 24
51 		 && elems->wmm_param[5] == 1)
52 		qos_info = elems->wmm_param[6];
53 	else
54 		/* no valid wmm information or parameter element found */
55 		return false;
56 
57 	return qos_info & IEEE80211_WMM_IE_AP_QOSINFO_UAPSD;
58 }
59 
60 struct ieee80211_bss *
61 ieee80211_bss_info_update(struct ieee80211_local *local,
62 			  struct ieee80211_rx_status *rx_status,
63 			  struct ieee80211_mgmt *mgmt, size_t len,
64 			  struct ieee802_11_elems *elems,
65 			  struct ieee80211_channel *channel)
66 {
67 	bool beacon = ieee80211_is_beacon(mgmt->frame_control);
68 	struct cfg80211_bss *cbss;
69 	struct ieee80211_bss *bss;
70 	int clen, srlen;
71 	struct cfg80211_inform_bss bss_meta = {
72 		.boottime_ns = rx_status->boottime_ns,
73 	};
74 	bool signal_valid;
75 	struct ieee80211_sub_if_data *scan_sdata;
76 
77 	if (rx_status->flag & RX_FLAG_NO_SIGNAL_VAL)
78 		bss_meta.signal = 0; /* invalid signal indication */
79 	else if (ieee80211_hw_check(&local->hw, SIGNAL_DBM))
80 		bss_meta.signal = rx_status->signal * 100;
81 	else if (ieee80211_hw_check(&local->hw, SIGNAL_UNSPEC))
82 		bss_meta.signal = (rx_status->signal * 100) / local->hw.max_signal;
83 
84 	bss_meta.scan_width = NL80211_BSS_CHAN_WIDTH_20;
85 	if (rx_status->bw == RATE_INFO_BW_5)
86 		bss_meta.scan_width = NL80211_BSS_CHAN_WIDTH_5;
87 	else if (rx_status->bw == RATE_INFO_BW_10)
88 		bss_meta.scan_width = NL80211_BSS_CHAN_WIDTH_10;
89 
90 	bss_meta.chan = channel;
91 
92 	rcu_read_lock();
93 	scan_sdata = rcu_dereference(local->scan_sdata);
94 	if (scan_sdata && scan_sdata->vif.type == NL80211_IFTYPE_STATION &&
95 	    scan_sdata->vif.bss_conf.assoc &&
96 	    ieee80211_have_rx_timestamp(rx_status)) {
97 		bss_meta.parent_tsf =
98 			ieee80211_calculate_rx_timestamp(local, rx_status,
99 							 len + FCS_LEN, 24);
100 		ether_addr_copy(bss_meta.parent_bssid,
101 				scan_sdata->vif.bss_conf.bssid);
102 	}
103 	rcu_read_unlock();
104 
105 	cbss = cfg80211_inform_bss_frame_data(local->hw.wiphy, &bss_meta,
106 					      mgmt, len, GFP_ATOMIC);
107 	if (!cbss)
108 		return NULL;
109 	/* In case the signal is invalid update the status */
110 	signal_valid = abs(channel->center_freq - cbss->channel->center_freq)
111 		<= local->hw.wiphy->max_adj_channel_rssi_comp;
112 	if (!signal_valid)
113 		rx_status->flag |= RX_FLAG_NO_SIGNAL_VAL;
114 
115 	bss = (void *)cbss->priv;
116 
117 	if (beacon)
118 		bss->device_ts_beacon = rx_status->device_timestamp;
119 	else
120 		bss->device_ts_presp = rx_status->device_timestamp;
121 
122 	if (elems->parse_error) {
123 		if (beacon)
124 			bss->corrupt_data |= IEEE80211_BSS_CORRUPT_BEACON;
125 		else
126 			bss->corrupt_data |= IEEE80211_BSS_CORRUPT_PROBE_RESP;
127 	} else {
128 		if (beacon)
129 			bss->corrupt_data &= ~IEEE80211_BSS_CORRUPT_BEACON;
130 		else
131 			bss->corrupt_data &= ~IEEE80211_BSS_CORRUPT_PROBE_RESP;
132 	}
133 
134 	/* save the ERP value so that it is available at association time */
135 	if (elems->erp_info && (!elems->parse_error ||
136 				!(bss->valid_data & IEEE80211_BSS_VALID_ERP))) {
137 		bss->erp_value = elems->erp_info[0];
138 		bss->has_erp_value = true;
139 		if (!elems->parse_error)
140 			bss->valid_data |= IEEE80211_BSS_VALID_ERP;
141 	}
142 
143 	/* replace old supported rates if we get new values */
144 	if (!elems->parse_error ||
145 	    !(bss->valid_data & IEEE80211_BSS_VALID_RATES)) {
146 		srlen = 0;
147 		if (elems->supp_rates) {
148 			clen = IEEE80211_MAX_SUPP_RATES;
149 			if (clen > elems->supp_rates_len)
150 				clen = elems->supp_rates_len;
151 			memcpy(bss->supp_rates, elems->supp_rates, clen);
152 			srlen += clen;
153 		}
154 		if (elems->ext_supp_rates) {
155 			clen = IEEE80211_MAX_SUPP_RATES - srlen;
156 			if (clen > elems->ext_supp_rates_len)
157 				clen = elems->ext_supp_rates_len;
158 			memcpy(bss->supp_rates + srlen, elems->ext_supp_rates,
159 			       clen);
160 			srlen += clen;
161 		}
162 		if (srlen) {
163 			bss->supp_rates_len = srlen;
164 			if (!elems->parse_error)
165 				bss->valid_data |= IEEE80211_BSS_VALID_RATES;
166 		}
167 	}
168 
169 	if (!elems->parse_error ||
170 	    !(bss->valid_data & IEEE80211_BSS_VALID_WMM)) {
171 		bss->wmm_used = elems->wmm_param || elems->wmm_info;
172 		bss->uapsd_supported = is_uapsd_supported(elems);
173 		if (!elems->parse_error)
174 			bss->valid_data |= IEEE80211_BSS_VALID_WMM;
175 	}
176 
177 	if (beacon) {
178 		struct ieee80211_supported_band *sband =
179 			local->hw.wiphy->bands[rx_status->band];
180 		if (!(rx_status->encoding == RX_ENC_HT) &&
181 		    !(rx_status->encoding == RX_ENC_VHT))
182 			bss->beacon_rate =
183 				&sband->bitrates[rx_status->rate_idx];
184 	}
185 
186 	return bss;
187 }
188 
189 static bool ieee80211_scan_accept_presp(struct ieee80211_sub_if_data *sdata,
190 					u32 scan_flags, const u8 *da)
191 {
192 	if (!sdata)
193 		return false;
194 	/* accept broadcast for OCE */
195 	if (scan_flags & NL80211_SCAN_FLAG_ACCEPT_BCAST_PROBE_RESP &&
196 	    is_broadcast_ether_addr(da))
197 		return true;
198 	if (scan_flags & NL80211_SCAN_FLAG_RANDOM_ADDR)
199 		return true;
200 	return ether_addr_equal(da, sdata->vif.addr);
201 }
202 
203 void ieee80211_scan_rx(struct ieee80211_local *local, struct sk_buff *skb)
204 {
205 	struct ieee80211_rx_status *rx_status = IEEE80211_SKB_RXCB(skb);
206 	struct ieee80211_sub_if_data *sdata1, *sdata2;
207 	struct ieee80211_mgmt *mgmt = (void *)skb->data;
208 	struct ieee80211_bss *bss;
209 	u8 *elements;
210 	struct ieee80211_channel *channel;
211 	size_t baselen;
212 	struct ieee802_11_elems elems;
213 
214 	if (skb->len < 24 ||
215 	    (!ieee80211_is_probe_resp(mgmt->frame_control) &&
216 	     !ieee80211_is_beacon(mgmt->frame_control)))
217 		return;
218 
219 	sdata1 = rcu_dereference(local->scan_sdata);
220 	sdata2 = rcu_dereference(local->sched_scan_sdata);
221 
222 	if (likely(!sdata1 && !sdata2))
223 		return;
224 
225 	if (ieee80211_is_probe_resp(mgmt->frame_control)) {
226 		struct cfg80211_scan_request *scan_req;
227 		struct cfg80211_sched_scan_request *sched_scan_req;
228 		u32 scan_req_flags = 0, sched_scan_req_flags = 0;
229 
230 		scan_req = rcu_dereference(local->scan_req);
231 		sched_scan_req = rcu_dereference(local->sched_scan_req);
232 
233 		if (scan_req)
234 			scan_req_flags = scan_req->flags;
235 
236 		if (sched_scan_req)
237 			sched_scan_req_flags = sched_scan_req->flags;
238 
239 		/* ignore ProbeResp to foreign address or non-bcast (OCE)
240 		 * unless scanning with randomised address
241 		 */
242 		if (!ieee80211_scan_accept_presp(sdata1, scan_req_flags,
243 						 mgmt->da) &&
244 		    !ieee80211_scan_accept_presp(sdata2, sched_scan_req_flags,
245 						 mgmt->da))
246 			return;
247 
248 		elements = mgmt->u.probe_resp.variable;
249 		baselen = offsetof(struct ieee80211_mgmt, u.probe_resp.variable);
250 	} else {
251 		baselen = offsetof(struct ieee80211_mgmt, u.beacon.variable);
252 		elements = mgmt->u.beacon.variable;
253 	}
254 
255 	if (baselen > skb->len)
256 		return;
257 
258 	ieee802_11_parse_elems(elements, skb->len - baselen, false, &elems);
259 
260 	channel = ieee80211_get_channel(local->hw.wiphy, rx_status->freq);
261 
262 	if (!channel || channel->flags & IEEE80211_CHAN_DISABLED)
263 		return;
264 
265 	bss = ieee80211_bss_info_update(local, rx_status,
266 					mgmt, skb->len, &elems,
267 					channel);
268 	if (bss)
269 		ieee80211_rx_bss_put(local, bss);
270 }
271 
272 static void
273 ieee80211_prepare_scan_chandef(struct cfg80211_chan_def *chandef,
274 			       enum nl80211_bss_scan_width scan_width)
275 {
276 	memset(chandef, 0, sizeof(*chandef));
277 	switch (scan_width) {
278 	case NL80211_BSS_CHAN_WIDTH_5:
279 		chandef->width = NL80211_CHAN_WIDTH_5;
280 		break;
281 	case NL80211_BSS_CHAN_WIDTH_10:
282 		chandef->width = NL80211_CHAN_WIDTH_10;
283 		break;
284 	default:
285 		chandef->width = NL80211_CHAN_WIDTH_20_NOHT;
286 		break;
287 	}
288 }
289 
290 /* return false if no more work */
291 static bool ieee80211_prep_hw_scan(struct ieee80211_local *local)
292 {
293 	struct cfg80211_scan_request *req;
294 	struct cfg80211_chan_def chandef;
295 	u8 bands_used = 0;
296 	int i, ielen, n_chans;
297 	u32 flags = 0;
298 
299 	req = rcu_dereference_protected(local->scan_req,
300 					lockdep_is_held(&local->mtx));
301 
302 	if (test_bit(SCAN_HW_CANCELLED, &local->scanning))
303 		return false;
304 
305 	if (ieee80211_hw_check(&local->hw, SINGLE_SCAN_ON_ALL_BANDS)) {
306 		for (i = 0; i < req->n_channels; i++) {
307 			local->hw_scan_req->req.channels[i] = req->channels[i];
308 			bands_used |= BIT(req->channels[i]->band);
309 		}
310 
311 		n_chans = req->n_channels;
312 	} else {
313 		do {
314 			if (local->hw_scan_band == NUM_NL80211_BANDS)
315 				return false;
316 
317 			n_chans = 0;
318 
319 			for (i = 0; i < req->n_channels; i++) {
320 				if (req->channels[i]->band !=
321 				    local->hw_scan_band)
322 					continue;
323 				local->hw_scan_req->req.channels[n_chans] =
324 							req->channels[i];
325 				n_chans++;
326 				bands_used |= BIT(req->channels[i]->band);
327 			}
328 
329 			local->hw_scan_band++;
330 		} while (!n_chans);
331 	}
332 
333 	local->hw_scan_req->req.n_channels = n_chans;
334 	ieee80211_prepare_scan_chandef(&chandef, req->scan_width);
335 
336 	if (req->flags & NL80211_SCAN_FLAG_MIN_PREQ_CONTENT)
337 		flags |= IEEE80211_PROBE_FLAG_MIN_CONTENT;
338 
339 	ielen = ieee80211_build_preq_ies(local,
340 					 (u8 *)local->hw_scan_req->req.ie,
341 					 local->hw_scan_ies_bufsize,
342 					 &local->hw_scan_req->ies,
343 					 req->ie, req->ie_len,
344 					 bands_used, req->rates, &chandef,
345 					 flags);
346 	local->hw_scan_req->req.ie_len = ielen;
347 	local->hw_scan_req->req.no_cck = req->no_cck;
348 	ether_addr_copy(local->hw_scan_req->req.mac_addr, req->mac_addr);
349 	ether_addr_copy(local->hw_scan_req->req.mac_addr_mask,
350 			req->mac_addr_mask);
351 	ether_addr_copy(local->hw_scan_req->req.bssid, req->bssid);
352 
353 	return true;
354 }
355 
356 static void __ieee80211_scan_completed(struct ieee80211_hw *hw, bool aborted)
357 {
358 	struct ieee80211_local *local = hw_to_local(hw);
359 	bool hw_scan = test_bit(SCAN_HW_SCANNING, &local->scanning);
360 	bool was_scanning = local->scanning;
361 	struct cfg80211_scan_request *scan_req;
362 	struct ieee80211_sub_if_data *scan_sdata;
363 	struct ieee80211_sub_if_data *sdata;
364 
365 	lockdep_assert_held(&local->mtx);
366 
367 	/*
368 	 * It's ok to abort a not-yet-running scan (that
369 	 * we have one at all will be verified by checking
370 	 * local->scan_req next), but not to complete it
371 	 * successfully.
372 	 */
373 	if (WARN_ON(!local->scanning && !aborted))
374 		aborted = true;
375 
376 	if (WARN_ON(!local->scan_req))
377 		return;
378 
379 	if (hw_scan && !aborted &&
380 	    !ieee80211_hw_check(&local->hw, SINGLE_SCAN_ON_ALL_BANDS) &&
381 	    ieee80211_prep_hw_scan(local)) {
382 		int rc;
383 
384 		rc = drv_hw_scan(local,
385 			rcu_dereference_protected(local->scan_sdata,
386 						  lockdep_is_held(&local->mtx)),
387 			local->hw_scan_req);
388 
389 		if (rc == 0)
390 			return;
391 
392 		/* HW scan failed and is going to be reported as aborted,
393 		 * so clear old scan info.
394 		 */
395 		memset(&local->scan_info, 0, sizeof(local->scan_info));
396 		aborted = true;
397 	}
398 
399 	kfree(local->hw_scan_req);
400 	local->hw_scan_req = NULL;
401 
402 	scan_req = rcu_dereference_protected(local->scan_req,
403 					     lockdep_is_held(&local->mtx));
404 
405 	if (scan_req != local->int_scan_req) {
406 		local->scan_info.aborted = aborted;
407 		cfg80211_scan_done(scan_req, &local->scan_info);
408 	}
409 	RCU_INIT_POINTER(local->scan_req, NULL);
410 
411 	scan_sdata = rcu_dereference_protected(local->scan_sdata,
412 					       lockdep_is_held(&local->mtx));
413 	RCU_INIT_POINTER(local->scan_sdata, NULL);
414 
415 	local->scanning = 0;
416 	local->scan_chandef.chan = NULL;
417 
418 	/* Set power back to normal operating levels. */
419 	ieee80211_hw_config(local, 0);
420 
421 	if (!hw_scan) {
422 		ieee80211_configure_filter(local);
423 		drv_sw_scan_complete(local, scan_sdata);
424 		ieee80211_offchannel_return(local);
425 	}
426 
427 	ieee80211_recalc_idle(local);
428 
429 	ieee80211_mlme_notify_scan_completed(local);
430 	ieee80211_ibss_notify_scan_completed(local);
431 
432 	/* Requeue all the work that might have been ignored while
433 	 * the scan was in progress; if there was none this will
434 	 * just be a no-op for the particular interface.
435 	 */
436 	list_for_each_entry_rcu(sdata, &local->interfaces, list) {
437 		if (ieee80211_sdata_running(sdata))
438 			ieee80211_queue_work(&sdata->local->hw, &sdata->work);
439 	}
440 
441 	if (was_scanning)
442 		ieee80211_start_next_roc(local);
443 }
444 
445 void ieee80211_scan_completed(struct ieee80211_hw *hw,
446 			      struct cfg80211_scan_info *info)
447 {
448 	struct ieee80211_local *local = hw_to_local(hw);
449 
450 	trace_api_scan_completed(local, info->aborted);
451 
452 	set_bit(SCAN_COMPLETED, &local->scanning);
453 	if (info->aborted)
454 		set_bit(SCAN_ABORTED, &local->scanning);
455 
456 	memcpy(&local->scan_info, info, sizeof(*info));
457 
458 	ieee80211_queue_delayed_work(&local->hw, &local->scan_work, 0);
459 }
460 EXPORT_SYMBOL(ieee80211_scan_completed);
461 
462 static int ieee80211_start_sw_scan(struct ieee80211_local *local,
463 				   struct ieee80211_sub_if_data *sdata)
464 {
465 	/* Software scan is not supported in multi-channel cases */
466 	if (local->use_chanctx)
467 		return -EOPNOTSUPP;
468 
469 	/*
470 	 * Hardware/driver doesn't support hw_scan, so use software
471 	 * scanning instead. First send a nullfunc frame with power save
472 	 * bit on so that AP will buffer the frames for us while we are not
473 	 * listening, then send probe requests to each channel and wait for
474 	 * the responses. After all channels are scanned, tune back to the
475 	 * original channel and send a nullfunc frame with power save bit
476 	 * off to trigger the AP to send us all the buffered frames.
477 	 *
478 	 * Note that while local->sw_scanning is true everything else but
479 	 * nullfunc frames and probe requests will be dropped in
480 	 * ieee80211_tx_h_check_assoc().
481 	 */
482 	drv_sw_scan_start(local, sdata, local->scan_addr);
483 
484 	local->leave_oper_channel_time = jiffies;
485 	local->next_scan_state = SCAN_DECISION;
486 	local->scan_channel_idx = 0;
487 
488 	ieee80211_offchannel_stop_vifs(local);
489 
490 	/* ensure nullfunc is transmitted before leaving operating channel */
491 	ieee80211_flush_queues(local, NULL, false);
492 
493 	ieee80211_configure_filter(local);
494 
495 	/* We need to set power level at maximum rate for scanning. */
496 	ieee80211_hw_config(local, 0);
497 
498 	ieee80211_queue_delayed_work(&local->hw,
499 				     &local->scan_work, 0);
500 
501 	return 0;
502 }
503 
504 static bool ieee80211_can_scan(struct ieee80211_local *local,
505 			       struct ieee80211_sub_if_data *sdata)
506 {
507 	if (ieee80211_is_radar_required(local))
508 		return false;
509 
510 	if (!list_empty(&local->roc_list))
511 		return false;
512 
513 	if (sdata->vif.type == NL80211_IFTYPE_STATION &&
514 	    sdata->u.mgd.flags & IEEE80211_STA_CONNECTION_POLL)
515 		return false;
516 
517 	return true;
518 }
519 
520 void ieee80211_run_deferred_scan(struct ieee80211_local *local)
521 {
522 	lockdep_assert_held(&local->mtx);
523 
524 	if (!local->scan_req || local->scanning)
525 		return;
526 
527 	if (!ieee80211_can_scan(local,
528 				rcu_dereference_protected(
529 					local->scan_sdata,
530 					lockdep_is_held(&local->mtx))))
531 		return;
532 
533 	ieee80211_queue_delayed_work(&local->hw, &local->scan_work,
534 				     round_jiffies_relative(0));
535 }
536 
537 static void ieee80211_send_scan_probe_req(struct ieee80211_sub_if_data *sdata,
538 					  const u8 *src, const u8 *dst,
539 					  const u8 *ssid, size_t ssid_len,
540 					  const u8 *ie, size_t ie_len,
541 					  u32 ratemask, u32 flags, u32 tx_flags,
542 					  struct ieee80211_channel *channel)
543 {
544 	struct sk_buff *skb;
545 	u32 txdata_flags = 0;
546 
547 	skb = ieee80211_build_probe_req(sdata, src, dst, ratemask, channel,
548 					ssid, ssid_len,
549 					ie, ie_len, flags);
550 
551 	if (skb) {
552 		if (flags & IEEE80211_PROBE_FLAG_RANDOM_SN) {
553 			struct ieee80211_hdr *hdr = (void *)skb->data;
554 			u16 sn = get_random_u32();
555 
556 			txdata_flags |= IEEE80211_TX_NO_SEQNO;
557 			hdr->seq_ctrl =
558 				cpu_to_le16(IEEE80211_SN_TO_SEQ(sn));
559 		}
560 		IEEE80211_SKB_CB(skb)->flags |= tx_flags;
561 		ieee80211_tx_skb_tid_band(sdata, skb, 7, channel->band,
562 					  txdata_flags);
563 	}
564 }
565 
566 static void ieee80211_scan_state_send_probe(struct ieee80211_local *local,
567 					    unsigned long *next_delay)
568 {
569 	int i;
570 	struct ieee80211_sub_if_data *sdata;
571 	struct cfg80211_scan_request *scan_req;
572 	enum nl80211_band band = local->hw.conf.chandef.chan->band;
573 	u32 flags = 0, tx_flags;
574 
575 	scan_req = rcu_dereference_protected(local->scan_req,
576 					     lockdep_is_held(&local->mtx));
577 
578 	tx_flags = IEEE80211_TX_INTFL_OFFCHAN_TX_OK;
579 	if (scan_req->no_cck)
580 		tx_flags |= IEEE80211_TX_CTL_NO_CCK_RATE;
581 	if (scan_req->flags & NL80211_SCAN_FLAG_MIN_PREQ_CONTENT)
582 		flags |= IEEE80211_PROBE_FLAG_MIN_CONTENT;
583 	if (scan_req->flags & NL80211_SCAN_FLAG_RANDOM_SN)
584 		flags |= IEEE80211_PROBE_FLAG_RANDOM_SN;
585 
586 	sdata = rcu_dereference_protected(local->scan_sdata,
587 					  lockdep_is_held(&local->mtx));
588 
589 	for (i = 0; i < scan_req->n_ssids; i++)
590 		ieee80211_send_scan_probe_req(
591 			sdata, local->scan_addr, scan_req->bssid,
592 			scan_req->ssids[i].ssid, scan_req->ssids[i].ssid_len,
593 			scan_req->ie, scan_req->ie_len,
594 			scan_req->rates[band], flags,
595 			tx_flags, local->hw.conf.chandef.chan);
596 
597 	/*
598 	 * After sending probe requests, wait for probe responses
599 	 * on the channel.
600 	 */
601 	*next_delay = IEEE80211_CHANNEL_TIME;
602 	local->next_scan_state = SCAN_DECISION;
603 }
604 
605 static int __ieee80211_start_scan(struct ieee80211_sub_if_data *sdata,
606 				  struct cfg80211_scan_request *req)
607 {
608 	struct ieee80211_local *local = sdata->local;
609 	bool hw_scan = local->ops->hw_scan;
610 	int rc;
611 
612 	lockdep_assert_held(&local->mtx);
613 
614 	if (local->scan_req || ieee80211_is_radar_required(local))
615 		return -EBUSY;
616 
617 	if (!ieee80211_can_scan(local, sdata)) {
618 		/* wait for the work to finish/time out */
619 		rcu_assign_pointer(local->scan_req, req);
620 		rcu_assign_pointer(local->scan_sdata, sdata);
621 		return 0;
622 	}
623 
624  again:
625 	if (hw_scan) {
626 		u8 *ies;
627 
628 		local->hw_scan_ies_bufsize = local->scan_ies_len + req->ie_len;
629 
630 		if (ieee80211_hw_check(&local->hw, SINGLE_SCAN_ON_ALL_BANDS)) {
631 			int i, n_bands = 0;
632 			u8 bands_counted = 0;
633 
634 			for (i = 0; i < req->n_channels; i++) {
635 				if (bands_counted & BIT(req->channels[i]->band))
636 					continue;
637 				bands_counted |= BIT(req->channels[i]->band);
638 				n_bands++;
639 			}
640 
641 			local->hw_scan_ies_bufsize *= n_bands;
642 		}
643 
644 		local->hw_scan_req = kmalloc(
645 				sizeof(*local->hw_scan_req) +
646 				req->n_channels * sizeof(req->channels[0]) +
647 				local->hw_scan_ies_bufsize, GFP_KERNEL);
648 		if (!local->hw_scan_req)
649 			return -ENOMEM;
650 
651 		local->hw_scan_req->req.ssids = req->ssids;
652 		local->hw_scan_req->req.n_ssids = req->n_ssids;
653 		ies = (u8 *)local->hw_scan_req +
654 			sizeof(*local->hw_scan_req) +
655 			req->n_channels * sizeof(req->channels[0]);
656 		local->hw_scan_req->req.ie = ies;
657 		local->hw_scan_req->req.flags = req->flags;
658 		eth_broadcast_addr(local->hw_scan_req->req.bssid);
659 		local->hw_scan_req->req.duration = req->duration;
660 		local->hw_scan_req->req.duration_mandatory =
661 			req->duration_mandatory;
662 
663 		local->hw_scan_band = 0;
664 
665 		/*
666 		 * After allocating local->hw_scan_req, we must
667 		 * go through until ieee80211_prep_hw_scan(), so
668 		 * anything that might be changed here and leave
669 		 * this function early must not go after this
670 		 * allocation.
671 		 */
672 	}
673 
674 	rcu_assign_pointer(local->scan_req, req);
675 	rcu_assign_pointer(local->scan_sdata, sdata);
676 
677 	if (req->flags & NL80211_SCAN_FLAG_RANDOM_ADDR)
678 		get_random_mask_addr(local->scan_addr,
679 				     req->mac_addr,
680 				     req->mac_addr_mask);
681 	else
682 		memcpy(local->scan_addr, sdata->vif.addr, ETH_ALEN);
683 
684 	if (hw_scan) {
685 		__set_bit(SCAN_HW_SCANNING, &local->scanning);
686 	} else if ((req->n_channels == 1) &&
687 		   (req->channels[0] == local->_oper_chandef.chan)) {
688 		/*
689 		 * If we are scanning only on the operating channel
690 		 * then we do not need to stop normal activities
691 		 */
692 		unsigned long next_delay;
693 
694 		__set_bit(SCAN_ONCHANNEL_SCANNING, &local->scanning);
695 
696 		ieee80211_recalc_idle(local);
697 
698 		/* Notify driver scan is starting, keep order of operations
699 		 * same as normal software scan, in case that matters. */
700 		drv_sw_scan_start(local, sdata, local->scan_addr);
701 
702 		ieee80211_configure_filter(local); /* accept probe-responses */
703 
704 		/* We need to ensure power level is at max for scanning. */
705 		ieee80211_hw_config(local, 0);
706 
707 		if ((req->channels[0]->flags & (IEEE80211_CHAN_NO_IR |
708 						IEEE80211_CHAN_RADAR)) ||
709 		    !req->n_ssids) {
710 			next_delay = IEEE80211_PASSIVE_CHANNEL_TIME;
711 		} else {
712 			ieee80211_scan_state_send_probe(local, &next_delay);
713 			next_delay = IEEE80211_CHANNEL_TIME;
714 		}
715 
716 		/* Now, just wait a bit and we are all done! */
717 		ieee80211_queue_delayed_work(&local->hw, &local->scan_work,
718 					     next_delay);
719 		return 0;
720 	} else {
721 		/* Do normal software scan */
722 		__set_bit(SCAN_SW_SCANNING, &local->scanning);
723 	}
724 
725 	ieee80211_recalc_idle(local);
726 
727 	if (hw_scan) {
728 		WARN_ON(!ieee80211_prep_hw_scan(local));
729 		rc = drv_hw_scan(local, sdata, local->hw_scan_req);
730 	} else {
731 		rc = ieee80211_start_sw_scan(local, sdata);
732 	}
733 
734 	if (rc) {
735 		kfree(local->hw_scan_req);
736 		local->hw_scan_req = NULL;
737 		local->scanning = 0;
738 
739 		ieee80211_recalc_idle(local);
740 
741 		local->scan_req = NULL;
742 		RCU_INIT_POINTER(local->scan_sdata, NULL);
743 	}
744 
745 	if (hw_scan && rc == 1) {
746 		/*
747 		 * we can't fall back to software for P2P-GO
748 		 * as it must update NoA etc.
749 		 */
750 		if (ieee80211_vif_type_p2p(&sdata->vif) ==
751 				NL80211_IFTYPE_P2P_GO)
752 			return -EOPNOTSUPP;
753 		hw_scan = false;
754 		goto again;
755 	}
756 
757 	return rc;
758 }
759 
760 static unsigned long
761 ieee80211_scan_get_channel_time(struct ieee80211_channel *chan)
762 {
763 	/*
764 	 * TODO: channel switching also consumes quite some time,
765 	 * add that delay as well to get a better estimation
766 	 */
767 	if (chan->flags & (IEEE80211_CHAN_NO_IR | IEEE80211_CHAN_RADAR))
768 		return IEEE80211_PASSIVE_CHANNEL_TIME;
769 	return IEEE80211_PROBE_DELAY + IEEE80211_CHANNEL_TIME;
770 }
771 
772 static void ieee80211_scan_state_decision(struct ieee80211_local *local,
773 					  unsigned long *next_delay)
774 {
775 	bool associated = false;
776 	bool tx_empty = true;
777 	bool bad_latency;
778 	struct ieee80211_sub_if_data *sdata;
779 	struct ieee80211_channel *next_chan;
780 	enum mac80211_scan_state next_scan_state;
781 	struct cfg80211_scan_request *scan_req;
782 
783 	/*
784 	 * check if at least one STA interface is associated,
785 	 * check if at least one STA interface has pending tx frames
786 	 * and grab the lowest used beacon interval
787 	 */
788 	mutex_lock(&local->iflist_mtx);
789 	list_for_each_entry(sdata, &local->interfaces, list) {
790 		if (!ieee80211_sdata_running(sdata))
791 			continue;
792 
793 		if (sdata->vif.type == NL80211_IFTYPE_STATION) {
794 			if (sdata->u.mgd.associated) {
795 				associated = true;
796 
797 				if (!qdisc_all_tx_empty(sdata->dev)) {
798 					tx_empty = false;
799 					break;
800 				}
801 			}
802 		}
803 	}
804 	mutex_unlock(&local->iflist_mtx);
805 
806 	scan_req = rcu_dereference_protected(local->scan_req,
807 					     lockdep_is_held(&local->mtx));
808 
809 	next_chan = scan_req->channels[local->scan_channel_idx];
810 
811 	/*
812 	 * we're currently scanning a different channel, let's
813 	 * see if we can scan another channel without interfering
814 	 * with the current traffic situation.
815 	 *
816 	 * Keep good latency, do not stay off-channel more than 125 ms.
817 	 */
818 
819 	bad_latency = time_after(jiffies +
820 				 ieee80211_scan_get_channel_time(next_chan),
821 				 local->leave_oper_channel_time + HZ / 8);
822 
823 	if (associated && !tx_empty) {
824 		if (scan_req->flags & NL80211_SCAN_FLAG_LOW_PRIORITY)
825 			next_scan_state = SCAN_ABORT;
826 		else
827 			next_scan_state = SCAN_SUSPEND;
828 	} else if (associated && bad_latency) {
829 		next_scan_state = SCAN_SUSPEND;
830 	} else {
831 		next_scan_state = SCAN_SET_CHANNEL;
832 	}
833 
834 	local->next_scan_state = next_scan_state;
835 
836 	*next_delay = 0;
837 }
838 
839 static void ieee80211_scan_state_set_channel(struct ieee80211_local *local,
840 					     unsigned long *next_delay)
841 {
842 	int skip;
843 	struct ieee80211_channel *chan;
844 	enum nl80211_bss_scan_width oper_scan_width;
845 	struct cfg80211_scan_request *scan_req;
846 
847 	scan_req = rcu_dereference_protected(local->scan_req,
848 					     lockdep_is_held(&local->mtx));
849 
850 	skip = 0;
851 	chan = scan_req->channels[local->scan_channel_idx];
852 
853 	local->scan_chandef.chan = chan;
854 	local->scan_chandef.center_freq1 = chan->center_freq;
855 	local->scan_chandef.center_freq2 = 0;
856 	switch (scan_req->scan_width) {
857 	case NL80211_BSS_CHAN_WIDTH_5:
858 		local->scan_chandef.width = NL80211_CHAN_WIDTH_5;
859 		break;
860 	case NL80211_BSS_CHAN_WIDTH_10:
861 		local->scan_chandef.width = NL80211_CHAN_WIDTH_10;
862 		break;
863 	case NL80211_BSS_CHAN_WIDTH_20:
864 		/* If scanning on oper channel, use whatever channel-type
865 		 * is currently in use.
866 		 */
867 		oper_scan_width = cfg80211_chandef_to_scan_width(
868 					&local->_oper_chandef);
869 		if (chan == local->_oper_chandef.chan &&
870 		    oper_scan_width == scan_req->scan_width)
871 			local->scan_chandef = local->_oper_chandef;
872 		else
873 			local->scan_chandef.width = NL80211_CHAN_WIDTH_20_NOHT;
874 		break;
875 	}
876 
877 	if (ieee80211_hw_config(local, IEEE80211_CONF_CHANGE_CHANNEL))
878 		skip = 1;
879 
880 	/* advance state machine to next channel/band */
881 	local->scan_channel_idx++;
882 
883 	if (skip) {
884 		/* if we skip this channel return to the decision state */
885 		local->next_scan_state = SCAN_DECISION;
886 		return;
887 	}
888 
889 	/*
890 	 * Probe delay is used to update the NAV, cf. 11.1.3.2.2
891 	 * (which unfortunately doesn't say _why_ step a) is done,
892 	 * but it waits for the probe delay or until a frame is
893 	 * received - and the received frame would update the NAV).
894 	 * For now, we do not support waiting until a frame is
895 	 * received.
896 	 *
897 	 * In any case, it is not necessary for a passive scan.
898 	 */
899 	if ((chan->flags & (IEEE80211_CHAN_NO_IR | IEEE80211_CHAN_RADAR)) ||
900 	    !scan_req->n_ssids) {
901 		*next_delay = IEEE80211_PASSIVE_CHANNEL_TIME;
902 		local->next_scan_state = SCAN_DECISION;
903 		return;
904 	}
905 
906 	/* active scan, send probes */
907 	*next_delay = IEEE80211_PROBE_DELAY;
908 	local->next_scan_state = SCAN_SEND_PROBE;
909 }
910 
911 static void ieee80211_scan_state_suspend(struct ieee80211_local *local,
912 					 unsigned long *next_delay)
913 {
914 	/* switch back to the operating channel */
915 	local->scan_chandef.chan = NULL;
916 	ieee80211_hw_config(local, IEEE80211_CONF_CHANGE_CHANNEL);
917 
918 	/* disable PS */
919 	ieee80211_offchannel_return(local);
920 
921 	*next_delay = HZ / 5;
922 	/* afterwards, resume scan & go to next channel */
923 	local->next_scan_state = SCAN_RESUME;
924 }
925 
926 static void ieee80211_scan_state_resume(struct ieee80211_local *local,
927 					unsigned long *next_delay)
928 {
929 	ieee80211_offchannel_stop_vifs(local);
930 
931 	if (local->ops->flush) {
932 		ieee80211_flush_queues(local, NULL, false);
933 		*next_delay = 0;
934 	} else
935 		*next_delay = HZ / 10;
936 
937 	/* remember when we left the operating channel */
938 	local->leave_oper_channel_time = jiffies;
939 
940 	/* advance to the next channel to be scanned */
941 	local->next_scan_state = SCAN_SET_CHANNEL;
942 }
943 
944 void ieee80211_scan_work(struct work_struct *work)
945 {
946 	struct ieee80211_local *local =
947 		container_of(work, struct ieee80211_local, scan_work.work);
948 	struct ieee80211_sub_if_data *sdata;
949 	struct cfg80211_scan_request *scan_req;
950 	unsigned long next_delay = 0;
951 	bool aborted;
952 
953 	mutex_lock(&local->mtx);
954 
955 	if (!ieee80211_can_run_worker(local)) {
956 		aborted = true;
957 		goto out_complete;
958 	}
959 
960 	sdata = rcu_dereference_protected(local->scan_sdata,
961 					  lockdep_is_held(&local->mtx));
962 	scan_req = rcu_dereference_protected(local->scan_req,
963 					     lockdep_is_held(&local->mtx));
964 
965 	/* When scanning on-channel, the first-callback means completed. */
966 	if (test_bit(SCAN_ONCHANNEL_SCANNING, &local->scanning)) {
967 		aborted = test_and_clear_bit(SCAN_ABORTED, &local->scanning);
968 		goto out_complete;
969 	}
970 
971 	if (test_and_clear_bit(SCAN_COMPLETED, &local->scanning)) {
972 		aborted = test_and_clear_bit(SCAN_ABORTED, &local->scanning);
973 		goto out_complete;
974 	}
975 
976 	if (!sdata || !scan_req)
977 		goto out;
978 
979 	if (!local->scanning) {
980 		int rc;
981 
982 		RCU_INIT_POINTER(local->scan_req, NULL);
983 		RCU_INIT_POINTER(local->scan_sdata, NULL);
984 
985 		rc = __ieee80211_start_scan(sdata, scan_req);
986 		if (rc) {
987 			/* need to complete scan in cfg80211 */
988 			rcu_assign_pointer(local->scan_req, scan_req);
989 			aborted = true;
990 			goto out_complete;
991 		} else
992 			goto out;
993 	}
994 
995 	/*
996 	 * as long as no delay is required advance immediately
997 	 * without scheduling a new work
998 	 */
999 	do {
1000 		if (!ieee80211_sdata_running(sdata)) {
1001 			aborted = true;
1002 			goto out_complete;
1003 		}
1004 
1005 		switch (local->next_scan_state) {
1006 		case SCAN_DECISION:
1007 			/* if no more bands/channels left, complete scan */
1008 			if (local->scan_channel_idx >= scan_req->n_channels) {
1009 				aborted = false;
1010 				goto out_complete;
1011 			}
1012 			ieee80211_scan_state_decision(local, &next_delay);
1013 			break;
1014 		case SCAN_SET_CHANNEL:
1015 			ieee80211_scan_state_set_channel(local, &next_delay);
1016 			break;
1017 		case SCAN_SEND_PROBE:
1018 			ieee80211_scan_state_send_probe(local, &next_delay);
1019 			break;
1020 		case SCAN_SUSPEND:
1021 			ieee80211_scan_state_suspend(local, &next_delay);
1022 			break;
1023 		case SCAN_RESUME:
1024 			ieee80211_scan_state_resume(local, &next_delay);
1025 			break;
1026 		case SCAN_ABORT:
1027 			aborted = true;
1028 			goto out_complete;
1029 		}
1030 	} while (next_delay == 0);
1031 
1032 	ieee80211_queue_delayed_work(&local->hw, &local->scan_work, next_delay);
1033 	goto out;
1034 
1035 out_complete:
1036 	__ieee80211_scan_completed(&local->hw, aborted);
1037 out:
1038 	mutex_unlock(&local->mtx);
1039 }
1040 
1041 int ieee80211_request_scan(struct ieee80211_sub_if_data *sdata,
1042 			   struct cfg80211_scan_request *req)
1043 {
1044 	int res;
1045 
1046 	mutex_lock(&sdata->local->mtx);
1047 	res = __ieee80211_start_scan(sdata, req);
1048 	mutex_unlock(&sdata->local->mtx);
1049 
1050 	return res;
1051 }
1052 
1053 int ieee80211_request_ibss_scan(struct ieee80211_sub_if_data *sdata,
1054 				const u8 *ssid, u8 ssid_len,
1055 				struct ieee80211_channel **channels,
1056 				unsigned int n_channels,
1057 				enum nl80211_bss_scan_width scan_width)
1058 {
1059 	struct ieee80211_local *local = sdata->local;
1060 	int ret = -EBUSY, i, n_ch = 0;
1061 	enum nl80211_band band;
1062 
1063 	mutex_lock(&local->mtx);
1064 
1065 	/* busy scanning */
1066 	if (local->scan_req)
1067 		goto unlock;
1068 
1069 	/* fill internal scan request */
1070 	if (!channels) {
1071 		int max_n;
1072 
1073 		for (band = 0; band < NUM_NL80211_BANDS; band++) {
1074 			if (!local->hw.wiphy->bands[band])
1075 				continue;
1076 
1077 			max_n = local->hw.wiphy->bands[band]->n_channels;
1078 			for (i = 0; i < max_n; i++) {
1079 				struct ieee80211_channel *tmp_ch =
1080 				    &local->hw.wiphy->bands[band]->channels[i];
1081 
1082 				if (tmp_ch->flags & (IEEE80211_CHAN_NO_IR |
1083 						     IEEE80211_CHAN_DISABLED))
1084 					continue;
1085 
1086 				local->int_scan_req->channels[n_ch] = tmp_ch;
1087 				n_ch++;
1088 			}
1089 		}
1090 
1091 		if (WARN_ON_ONCE(n_ch == 0))
1092 			goto unlock;
1093 
1094 		local->int_scan_req->n_channels = n_ch;
1095 	} else {
1096 		for (i = 0; i < n_channels; i++) {
1097 			if (channels[i]->flags & (IEEE80211_CHAN_NO_IR |
1098 						  IEEE80211_CHAN_DISABLED))
1099 				continue;
1100 
1101 			local->int_scan_req->channels[n_ch] = channels[i];
1102 			n_ch++;
1103 		}
1104 
1105 		if (WARN_ON_ONCE(n_ch == 0))
1106 			goto unlock;
1107 
1108 		local->int_scan_req->n_channels = n_ch;
1109 	}
1110 
1111 	local->int_scan_req->ssids = &local->scan_ssid;
1112 	local->int_scan_req->n_ssids = 1;
1113 	local->int_scan_req->scan_width = scan_width;
1114 	memcpy(local->int_scan_req->ssids[0].ssid, ssid, IEEE80211_MAX_SSID_LEN);
1115 	local->int_scan_req->ssids[0].ssid_len = ssid_len;
1116 
1117 	ret = __ieee80211_start_scan(sdata, sdata->local->int_scan_req);
1118  unlock:
1119 	mutex_unlock(&local->mtx);
1120 	return ret;
1121 }
1122 
1123 /*
1124  * Only call this function when a scan can't be queued -- under RTNL.
1125  */
1126 void ieee80211_scan_cancel(struct ieee80211_local *local)
1127 {
1128 	/*
1129 	 * We are canceling software scan, or deferred scan that was not
1130 	 * yet really started (see __ieee80211_start_scan ).
1131 	 *
1132 	 * Regarding hardware scan:
1133 	 * - we can not call  __ieee80211_scan_completed() as when
1134 	 *   SCAN_HW_SCANNING bit is set this function change
1135 	 *   local->hw_scan_req to operate on 5G band, what race with
1136 	 *   driver which can use local->hw_scan_req
1137 	 *
1138 	 * - we can not cancel scan_work since driver can schedule it
1139 	 *   by ieee80211_scan_completed(..., true) to finish scan
1140 	 *
1141 	 * Hence we only call the cancel_hw_scan() callback, but the low-level
1142 	 * driver is still responsible for calling ieee80211_scan_completed()
1143 	 * after the scan was completed/aborted.
1144 	 */
1145 
1146 	mutex_lock(&local->mtx);
1147 	if (!local->scan_req)
1148 		goto out;
1149 
1150 	/*
1151 	 * We have a scan running and the driver already reported completion,
1152 	 * but the worker hasn't run yet or is stuck on the mutex - mark it as
1153 	 * cancelled.
1154 	 */
1155 	if (test_bit(SCAN_HW_SCANNING, &local->scanning) &&
1156 	    test_bit(SCAN_COMPLETED, &local->scanning)) {
1157 		set_bit(SCAN_HW_CANCELLED, &local->scanning);
1158 		goto out;
1159 	}
1160 
1161 	if (test_bit(SCAN_HW_SCANNING, &local->scanning)) {
1162 		/*
1163 		 * Make sure that __ieee80211_scan_completed doesn't trigger a
1164 		 * scan on another band.
1165 		 */
1166 		set_bit(SCAN_HW_CANCELLED, &local->scanning);
1167 		if (local->ops->cancel_hw_scan)
1168 			drv_cancel_hw_scan(local,
1169 				rcu_dereference_protected(local->scan_sdata,
1170 						lockdep_is_held(&local->mtx)));
1171 		goto out;
1172 	}
1173 
1174 	/*
1175 	 * If the work is currently running, it must be blocked on
1176 	 * the mutex, but we'll set scan_sdata = NULL and it'll
1177 	 * simply exit once it acquires the mutex.
1178 	 */
1179 	cancel_delayed_work(&local->scan_work);
1180 	/* and clean up */
1181 	memset(&local->scan_info, 0, sizeof(local->scan_info));
1182 	__ieee80211_scan_completed(&local->hw, true);
1183 out:
1184 	mutex_unlock(&local->mtx);
1185 }
1186 
1187 int __ieee80211_request_sched_scan_start(struct ieee80211_sub_if_data *sdata,
1188 					struct cfg80211_sched_scan_request *req)
1189 {
1190 	struct ieee80211_local *local = sdata->local;
1191 	struct ieee80211_scan_ies sched_scan_ies = {};
1192 	struct cfg80211_chan_def chandef;
1193 	int ret, i, iebufsz, num_bands = 0;
1194 	u32 rate_masks[NUM_NL80211_BANDS] = {};
1195 	u8 bands_used = 0;
1196 	u8 *ie;
1197 	u32 flags = 0;
1198 
1199 	iebufsz = local->scan_ies_len + req->ie_len;
1200 
1201 	lockdep_assert_held(&local->mtx);
1202 
1203 	if (!local->ops->sched_scan_start)
1204 		return -ENOTSUPP;
1205 
1206 	for (i = 0; i < NUM_NL80211_BANDS; i++) {
1207 		if (local->hw.wiphy->bands[i]) {
1208 			bands_used |= BIT(i);
1209 			rate_masks[i] = (u32) -1;
1210 			num_bands++;
1211 		}
1212 	}
1213 
1214 	if (req->flags & NL80211_SCAN_FLAG_MIN_PREQ_CONTENT)
1215 		flags |= IEEE80211_PROBE_FLAG_MIN_CONTENT;
1216 
1217 	ie = kcalloc(iebufsz, num_bands, GFP_KERNEL);
1218 	if (!ie) {
1219 		ret = -ENOMEM;
1220 		goto out;
1221 	}
1222 
1223 	ieee80211_prepare_scan_chandef(&chandef, req->scan_width);
1224 
1225 	ieee80211_build_preq_ies(local, ie, num_bands * iebufsz,
1226 				 &sched_scan_ies, req->ie,
1227 				 req->ie_len, bands_used, rate_masks, &chandef,
1228 				 flags);
1229 
1230 	ret = drv_sched_scan_start(local, sdata, req, &sched_scan_ies);
1231 	if (ret == 0) {
1232 		rcu_assign_pointer(local->sched_scan_sdata, sdata);
1233 		rcu_assign_pointer(local->sched_scan_req, req);
1234 	}
1235 
1236 	kfree(ie);
1237 
1238 out:
1239 	if (ret) {
1240 		/* Clean in case of failure after HW restart or upon resume. */
1241 		RCU_INIT_POINTER(local->sched_scan_sdata, NULL);
1242 		RCU_INIT_POINTER(local->sched_scan_req, NULL);
1243 	}
1244 
1245 	return ret;
1246 }
1247 
1248 int ieee80211_request_sched_scan_start(struct ieee80211_sub_if_data *sdata,
1249 				       struct cfg80211_sched_scan_request *req)
1250 {
1251 	struct ieee80211_local *local = sdata->local;
1252 	int ret;
1253 
1254 	mutex_lock(&local->mtx);
1255 
1256 	if (rcu_access_pointer(local->sched_scan_sdata)) {
1257 		mutex_unlock(&local->mtx);
1258 		return -EBUSY;
1259 	}
1260 
1261 	ret = __ieee80211_request_sched_scan_start(sdata, req);
1262 
1263 	mutex_unlock(&local->mtx);
1264 	return ret;
1265 }
1266 
1267 int ieee80211_request_sched_scan_stop(struct ieee80211_local *local)
1268 {
1269 	struct ieee80211_sub_if_data *sched_scan_sdata;
1270 	int ret = -ENOENT;
1271 
1272 	mutex_lock(&local->mtx);
1273 
1274 	if (!local->ops->sched_scan_stop) {
1275 		ret = -ENOTSUPP;
1276 		goto out;
1277 	}
1278 
1279 	/* We don't want to restart sched scan anymore. */
1280 	RCU_INIT_POINTER(local->sched_scan_req, NULL);
1281 
1282 	sched_scan_sdata = rcu_dereference_protected(local->sched_scan_sdata,
1283 						lockdep_is_held(&local->mtx));
1284 	if (sched_scan_sdata) {
1285 		ret = drv_sched_scan_stop(local, sched_scan_sdata);
1286 		if (!ret)
1287 			RCU_INIT_POINTER(local->sched_scan_sdata, NULL);
1288 	}
1289 out:
1290 	mutex_unlock(&local->mtx);
1291 
1292 	return ret;
1293 }
1294 
1295 void ieee80211_sched_scan_results(struct ieee80211_hw *hw)
1296 {
1297 	struct ieee80211_local *local = hw_to_local(hw);
1298 
1299 	trace_api_sched_scan_results(local);
1300 
1301 	cfg80211_sched_scan_results(hw->wiphy, 0);
1302 }
1303 EXPORT_SYMBOL(ieee80211_sched_scan_results);
1304 
1305 void ieee80211_sched_scan_end(struct ieee80211_local *local)
1306 {
1307 	mutex_lock(&local->mtx);
1308 
1309 	if (!rcu_access_pointer(local->sched_scan_sdata)) {
1310 		mutex_unlock(&local->mtx);
1311 		return;
1312 	}
1313 
1314 	RCU_INIT_POINTER(local->sched_scan_sdata, NULL);
1315 
1316 	/* If sched scan was aborted by the driver. */
1317 	RCU_INIT_POINTER(local->sched_scan_req, NULL);
1318 
1319 	mutex_unlock(&local->mtx);
1320 
1321 	cfg80211_sched_scan_stopped(local->hw.wiphy, 0);
1322 }
1323 
1324 void ieee80211_sched_scan_stopped_work(struct work_struct *work)
1325 {
1326 	struct ieee80211_local *local =
1327 		container_of(work, struct ieee80211_local,
1328 			     sched_scan_stopped_work);
1329 
1330 	ieee80211_sched_scan_end(local);
1331 }
1332 
1333 void ieee80211_sched_scan_stopped(struct ieee80211_hw *hw)
1334 {
1335 	struct ieee80211_local *local = hw_to_local(hw);
1336 
1337 	trace_api_sched_scan_stopped(local);
1338 
1339 	/*
1340 	 * this shouldn't really happen, so for simplicity
1341 	 * simply ignore it, and let mac80211 reconfigure
1342 	 * the sched scan later on.
1343 	 */
1344 	if (local->in_reconfig)
1345 		return;
1346 
1347 	schedule_work(&local->sched_scan_stopped_work);
1348 }
1349 EXPORT_SYMBOL(ieee80211_sched_scan_stopped);
1350