xref: /openbmc/linux/net/mac80211/scan.c (revision 3a83e4e6)
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 	if (elems->vht_cap_elem)
137 		bss->vht_cap_info =
138 			le32_to_cpu(elems->vht_cap_elem->vht_cap_info);
139 	else
140 		bss->vht_cap_info = 0;
141 }
142 
143 struct ieee80211_bss *
144 ieee80211_bss_info_update(struct ieee80211_local *local,
145 			  struct ieee80211_rx_status *rx_status,
146 			  struct ieee80211_mgmt *mgmt, size_t len,
147 			  struct ieee80211_channel *channel)
148 {
149 	bool beacon = ieee80211_is_beacon(mgmt->frame_control);
150 	struct cfg80211_bss *cbss, *non_tx_cbss;
151 	struct ieee80211_bss *bss, *non_tx_bss;
152 	struct cfg80211_inform_bss bss_meta = {
153 		.boottime_ns = rx_status->boottime_ns,
154 	};
155 	bool signal_valid;
156 	struct ieee80211_sub_if_data *scan_sdata;
157 	struct ieee802_11_elems elems;
158 	size_t baselen;
159 	u8 *elements;
160 
161 	if (rx_status->flag & RX_FLAG_NO_SIGNAL_VAL)
162 		bss_meta.signal = 0; /* invalid signal indication */
163 	else if (ieee80211_hw_check(&local->hw, SIGNAL_DBM))
164 		bss_meta.signal = rx_status->signal * 100;
165 	else if (ieee80211_hw_check(&local->hw, SIGNAL_UNSPEC))
166 		bss_meta.signal = (rx_status->signal * 100) / local->hw.max_signal;
167 
168 	bss_meta.scan_width = NL80211_BSS_CHAN_WIDTH_20;
169 	if (rx_status->bw == RATE_INFO_BW_5)
170 		bss_meta.scan_width = NL80211_BSS_CHAN_WIDTH_5;
171 	else if (rx_status->bw == RATE_INFO_BW_10)
172 		bss_meta.scan_width = NL80211_BSS_CHAN_WIDTH_10;
173 
174 	bss_meta.chan = channel;
175 
176 	rcu_read_lock();
177 	scan_sdata = rcu_dereference(local->scan_sdata);
178 	if (scan_sdata && scan_sdata->vif.type == NL80211_IFTYPE_STATION &&
179 	    scan_sdata->vif.bss_conf.assoc &&
180 	    ieee80211_have_rx_timestamp(rx_status)) {
181 		bss_meta.parent_tsf =
182 			ieee80211_calculate_rx_timestamp(local, rx_status,
183 							 len + FCS_LEN, 24);
184 		ether_addr_copy(bss_meta.parent_bssid,
185 				scan_sdata->vif.bss_conf.bssid);
186 	}
187 	rcu_read_unlock();
188 
189 	cbss = cfg80211_inform_bss_frame_data(local->hw.wiphy, &bss_meta,
190 					      mgmt, len, GFP_ATOMIC);
191 	if (!cbss)
192 		return NULL;
193 
194 	if (ieee80211_is_probe_resp(mgmt->frame_control)) {
195 		elements = mgmt->u.probe_resp.variable;
196 		baselen = offsetof(struct ieee80211_mgmt,
197 				   u.probe_resp.variable);
198 	} else {
199 		baselen = offsetof(struct ieee80211_mgmt, u.beacon.variable);
200 		elements = mgmt->u.beacon.variable;
201 	}
202 
203 	if (baselen > len)
204 		return NULL;
205 
206 	ieee802_11_parse_elems(elements, len - baselen, false, &elems,
207 			       mgmt->bssid, cbss->bssid);
208 
209 	/* In case the signal is invalid update the status */
210 	signal_valid = channel == cbss->channel;
211 	if (!signal_valid)
212 		rx_status->flag |= RX_FLAG_NO_SIGNAL_VAL;
213 
214 	bss = (void *)cbss->priv;
215 	ieee80211_update_bss_from_elems(local, bss, &elems, rx_status, beacon);
216 
217 	list_for_each_entry(non_tx_cbss, &cbss->nontrans_list, nontrans_list) {
218 		non_tx_bss = (void *)non_tx_cbss->priv;
219 
220 		ieee80211_update_bss_from_elems(local, non_tx_bss, &elems,
221 						rx_status, beacon);
222 	}
223 
224 	return bss;
225 }
226 
227 static bool ieee80211_scan_accept_presp(struct ieee80211_sub_if_data *sdata,
228 					u32 scan_flags, const u8 *da)
229 {
230 	if (!sdata)
231 		return false;
232 	/* accept broadcast for OCE */
233 	if (scan_flags & NL80211_SCAN_FLAG_ACCEPT_BCAST_PROBE_RESP &&
234 	    is_broadcast_ether_addr(da))
235 		return true;
236 	if (scan_flags & NL80211_SCAN_FLAG_RANDOM_ADDR)
237 		return true;
238 	return ether_addr_equal(da, sdata->vif.addr);
239 }
240 
241 void ieee80211_scan_rx(struct ieee80211_local *local, struct sk_buff *skb)
242 {
243 	struct ieee80211_rx_status *rx_status = IEEE80211_SKB_RXCB(skb);
244 	struct ieee80211_sub_if_data *sdata1, *sdata2;
245 	struct ieee80211_mgmt *mgmt = (void *)skb->data;
246 	struct ieee80211_bss *bss;
247 	struct ieee80211_channel *channel;
248 
249 	if (skb->len < 24 ||
250 	    (!ieee80211_is_probe_resp(mgmt->frame_control) &&
251 	     !ieee80211_is_beacon(mgmt->frame_control)))
252 		return;
253 
254 	sdata1 = rcu_dereference(local->scan_sdata);
255 	sdata2 = rcu_dereference(local->sched_scan_sdata);
256 
257 	if (likely(!sdata1 && !sdata2))
258 		return;
259 
260 	if (ieee80211_is_probe_resp(mgmt->frame_control)) {
261 		struct cfg80211_scan_request *scan_req;
262 		struct cfg80211_sched_scan_request *sched_scan_req;
263 		u32 scan_req_flags = 0, sched_scan_req_flags = 0;
264 
265 		scan_req = rcu_dereference(local->scan_req);
266 		sched_scan_req = rcu_dereference(local->sched_scan_req);
267 
268 		if (scan_req)
269 			scan_req_flags = scan_req->flags;
270 
271 		if (sched_scan_req)
272 			sched_scan_req_flags = sched_scan_req->flags;
273 
274 		/* ignore ProbeResp to foreign address or non-bcast (OCE)
275 		 * unless scanning with randomised address
276 		 */
277 		if (!ieee80211_scan_accept_presp(sdata1, scan_req_flags,
278 						 mgmt->da) &&
279 		    !ieee80211_scan_accept_presp(sdata2, sched_scan_req_flags,
280 						 mgmt->da))
281 			return;
282 	}
283 
284 	channel = ieee80211_get_channel_khz(local->hw.wiphy,
285 					ieee80211_rx_status_to_khz(rx_status));
286 
287 	if (!channel || channel->flags & IEEE80211_CHAN_DISABLED)
288 		return;
289 
290 	bss = ieee80211_bss_info_update(local, rx_status,
291 					mgmt, skb->len,
292 					channel);
293 	if (bss)
294 		ieee80211_rx_bss_put(local, bss);
295 }
296 
297 static void
298 ieee80211_prepare_scan_chandef(struct cfg80211_chan_def *chandef,
299 			       enum nl80211_bss_scan_width scan_width)
300 {
301 	memset(chandef, 0, sizeof(*chandef));
302 	switch (scan_width) {
303 	case NL80211_BSS_CHAN_WIDTH_5:
304 		chandef->width = NL80211_CHAN_WIDTH_5;
305 		break;
306 	case NL80211_BSS_CHAN_WIDTH_10:
307 		chandef->width = NL80211_CHAN_WIDTH_10;
308 		break;
309 	default:
310 		chandef->width = NL80211_CHAN_WIDTH_20_NOHT;
311 		break;
312 	}
313 }
314 
315 /* return false if no more work */
316 static bool ieee80211_prep_hw_scan(struct ieee80211_sub_if_data *sdata)
317 {
318 	struct ieee80211_local *local = sdata->local;
319 	struct cfg80211_scan_request *req;
320 	struct cfg80211_chan_def chandef;
321 	u8 bands_used = 0;
322 	int i, ielen, n_chans;
323 	u32 flags = 0;
324 
325 	req = rcu_dereference_protected(local->scan_req,
326 					lockdep_is_held(&local->mtx));
327 
328 	if (test_bit(SCAN_HW_CANCELLED, &local->scanning))
329 		return false;
330 
331 	if (ieee80211_hw_check(&local->hw, SINGLE_SCAN_ON_ALL_BANDS)) {
332 		for (i = 0; i < req->n_channels; i++) {
333 			local->hw_scan_req->req.channels[i] = req->channels[i];
334 			bands_used |= BIT(req->channels[i]->band);
335 		}
336 
337 		n_chans = req->n_channels;
338 	} else {
339 		do {
340 			if (local->hw_scan_band == NUM_NL80211_BANDS)
341 				return false;
342 
343 			n_chans = 0;
344 
345 			for (i = 0; i < req->n_channels; i++) {
346 				if (req->channels[i]->band !=
347 				    local->hw_scan_band)
348 					continue;
349 				local->hw_scan_req->req.channels[n_chans] =
350 							req->channels[i];
351 				n_chans++;
352 				bands_used |= BIT(req->channels[i]->band);
353 			}
354 
355 			local->hw_scan_band++;
356 		} while (!n_chans);
357 	}
358 
359 	local->hw_scan_req->req.n_channels = n_chans;
360 	ieee80211_prepare_scan_chandef(&chandef, req->scan_width);
361 
362 	if (req->flags & NL80211_SCAN_FLAG_MIN_PREQ_CONTENT)
363 		flags |= IEEE80211_PROBE_FLAG_MIN_CONTENT;
364 
365 	ielen = ieee80211_build_preq_ies(sdata,
366 					 (u8 *)local->hw_scan_req->req.ie,
367 					 local->hw_scan_ies_bufsize,
368 					 &local->hw_scan_req->ies,
369 					 req->ie, req->ie_len,
370 					 bands_used, req->rates, &chandef,
371 					 flags);
372 	local->hw_scan_req->req.ie_len = ielen;
373 	local->hw_scan_req->req.no_cck = req->no_cck;
374 	ether_addr_copy(local->hw_scan_req->req.mac_addr, req->mac_addr);
375 	ether_addr_copy(local->hw_scan_req->req.mac_addr_mask,
376 			req->mac_addr_mask);
377 	ether_addr_copy(local->hw_scan_req->req.bssid, req->bssid);
378 
379 	return true;
380 }
381 
382 static void __ieee80211_scan_completed(struct ieee80211_hw *hw, bool aborted)
383 {
384 	struct ieee80211_local *local = hw_to_local(hw);
385 	bool hw_scan = test_bit(SCAN_HW_SCANNING, &local->scanning);
386 	bool was_scanning = local->scanning;
387 	struct cfg80211_scan_request *scan_req;
388 	struct ieee80211_sub_if_data *scan_sdata;
389 	struct ieee80211_sub_if_data *sdata;
390 
391 	lockdep_assert_held(&local->mtx);
392 
393 	/*
394 	 * It's ok to abort a not-yet-running scan (that
395 	 * we have one at all will be verified by checking
396 	 * local->scan_req next), but not to complete it
397 	 * successfully.
398 	 */
399 	if (WARN_ON(!local->scanning && !aborted))
400 		aborted = true;
401 
402 	if (WARN_ON(!local->scan_req))
403 		return;
404 
405 	scan_sdata = rcu_dereference_protected(local->scan_sdata,
406 					       lockdep_is_held(&local->mtx));
407 
408 	if (hw_scan && !aborted &&
409 	    !ieee80211_hw_check(&local->hw, SINGLE_SCAN_ON_ALL_BANDS) &&
410 	    ieee80211_prep_hw_scan(scan_sdata)) {
411 		int rc;
412 
413 		rc = drv_hw_scan(local,
414 			rcu_dereference_protected(local->scan_sdata,
415 						  lockdep_is_held(&local->mtx)),
416 			local->hw_scan_req);
417 
418 		if (rc == 0)
419 			return;
420 
421 		/* HW scan failed and is going to be reported as aborted,
422 		 * so clear old scan info.
423 		 */
424 		memset(&local->scan_info, 0, sizeof(local->scan_info));
425 		aborted = true;
426 	}
427 
428 	kfree(local->hw_scan_req);
429 	local->hw_scan_req = NULL;
430 
431 	scan_req = rcu_dereference_protected(local->scan_req,
432 					     lockdep_is_held(&local->mtx));
433 
434 	if (scan_req != local->int_scan_req) {
435 		local->scan_info.aborted = aborted;
436 		cfg80211_scan_done(scan_req, &local->scan_info);
437 	}
438 	RCU_INIT_POINTER(local->scan_req, NULL);
439 	RCU_INIT_POINTER(local->scan_sdata, NULL);
440 
441 	local->scanning = 0;
442 	local->scan_chandef.chan = NULL;
443 
444 	/* Set power back to normal operating levels. */
445 	ieee80211_hw_config(local, 0);
446 
447 	if (!hw_scan) {
448 		ieee80211_configure_filter(local);
449 		drv_sw_scan_complete(local, scan_sdata);
450 		ieee80211_offchannel_return(local);
451 	}
452 
453 	ieee80211_recalc_idle(local);
454 
455 	ieee80211_mlme_notify_scan_completed(local);
456 	ieee80211_ibss_notify_scan_completed(local);
457 
458 	/* Requeue all the work that might have been ignored while
459 	 * the scan was in progress; if there was none this will
460 	 * just be a no-op for the particular interface.
461 	 */
462 	list_for_each_entry_rcu(sdata, &local->interfaces, list) {
463 		if (ieee80211_sdata_running(sdata))
464 			ieee80211_queue_work(&sdata->local->hw, &sdata->work);
465 	}
466 
467 	if (was_scanning)
468 		ieee80211_start_next_roc(local);
469 }
470 
471 void ieee80211_scan_completed(struct ieee80211_hw *hw,
472 			      struct cfg80211_scan_info *info)
473 {
474 	struct ieee80211_local *local = hw_to_local(hw);
475 
476 	trace_api_scan_completed(local, info->aborted);
477 
478 	set_bit(SCAN_COMPLETED, &local->scanning);
479 	if (info->aborted)
480 		set_bit(SCAN_ABORTED, &local->scanning);
481 
482 	memcpy(&local->scan_info, info, sizeof(*info));
483 
484 	ieee80211_queue_delayed_work(&local->hw, &local->scan_work, 0);
485 }
486 EXPORT_SYMBOL(ieee80211_scan_completed);
487 
488 static int ieee80211_start_sw_scan(struct ieee80211_local *local,
489 				   struct ieee80211_sub_if_data *sdata)
490 {
491 	/* Software scan is not supported in multi-channel cases */
492 	if (local->use_chanctx)
493 		return -EOPNOTSUPP;
494 
495 	/*
496 	 * Hardware/driver doesn't support hw_scan, so use software
497 	 * scanning instead. First send a nullfunc frame with power save
498 	 * bit on so that AP will buffer the frames for us while we are not
499 	 * listening, then send probe requests to each channel and wait for
500 	 * the responses. After all channels are scanned, tune back to the
501 	 * original channel and send a nullfunc frame with power save bit
502 	 * off to trigger the AP to send us all the buffered frames.
503 	 *
504 	 * Note that while local->sw_scanning is true everything else but
505 	 * nullfunc frames and probe requests will be dropped in
506 	 * ieee80211_tx_h_check_assoc().
507 	 */
508 	drv_sw_scan_start(local, sdata, local->scan_addr);
509 
510 	local->leave_oper_channel_time = jiffies;
511 	local->next_scan_state = SCAN_DECISION;
512 	local->scan_channel_idx = 0;
513 
514 	ieee80211_offchannel_stop_vifs(local);
515 
516 	/* ensure nullfunc is transmitted before leaving operating channel */
517 	ieee80211_flush_queues(local, NULL, false);
518 
519 	ieee80211_configure_filter(local);
520 
521 	/* We need to set power level at maximum rate for scanning. */
522 	ieee80211_hw_config(local, 0);
523 
524 	ieee80211_queue_delayed_work(&local->hw,
525 				     &local->scan_work, 0);
526 
527 	return 0;
528 }
529 
530 static bool __ieee80211_can_leave_ch(struct ieee80211_sub_if_data *sdata)
531 {
532 	struct ieee80211_local *local = sdata->local;
533 	struct ieee80211_sub_if_data *sdata_iter;
534 
535 	if (!ieee80211_is_radar_required(local))
536 		return true;
537 
538 	if (!regulatory_pre_cac_allowed(local->hw.wiphy))
539 		return false;
540 
541 	mutex_lock(&local->iflist_mtx);
542 	list_for_each_entry(sdata_iter, &local->interfaces, list) {
543 		if (sdata_iter->wdev.cac_started) {
544 			mutex_unlock(&local->iflist_mtx);
545 			return false;
546 		}
547 	}
548 	mutex_unlock(&local->iflist_mtx);
549 
550 	return true;
551 }
552 
553 static bool ieee80211_can_scan(struct ieee80211_local *local,
554 			       struct ieee80211_sub_if_data *sdata)
555 {
556 	if (!__ieee80211_can_leave_ch(sdata))
557 		return false;
558 
559 	if (!list_empty(&local->roc_list))
560 		return false;
561 
562 	if (sdata->vif.type == NL80211_IFTYPE_STATION &&
563 	    sdata->u.mgd.flags & IEEE80211_STA_CONNECTION_POLL)
564 		return false;
565 
566 	return true;
567 }
568 
569 void ieee80211_run_deferred_scan(struct ieee80211_local *local)
570 {
571 	lockdep_assert_held(&local->mtx);
572 
573 	if (!local->scan_req || local->scanning)
574 		return;
575 
576 	if (!ieee80211_can_scan(local,
577 				rcu_dereference_protected(
578 					local->scan_sdata,
579 					lockdep_is_held(&local->mtx))))
580 		return;
581 
582 	ieee80211_queue_delayed_work(&local->hw, &local->scan_work,
583 				     round_jiffies_relative(0));
584 }
585 
586 static void ieee80211_send_scan_probe_req(struct ieee80211_sub_if_data *sdata,
587 					  const u8 *src, const u8 *dst,
588 					  const u8 *ssid, size_t ssid_len,
589 					  const u8 *ie, size_t ie_len,
590 					  u32 ratemask, u32 flags, u32 tx_flags,
591 					  struct ieee80211_channel *channel)
592 {
593 	struct sk_buff *skb;
594 
595 	skb = ieee80211_build_probe_req(sdata, src, dst, ratemask, channel,
596 					ssid, ssid_len,
597 					ie, ie_len, flags);
598 
599 	if (skb) {
600 		if (flags & IEEE80211_PROBE_FLAG_RANDOM_SN) {
601 			struct ieee80211_hdr *hdr = (void *)skb->data;
602 			struct ieee80211_tx_info *info = IEEE80211_SKB_CB(skb);
603 			u16 sn = get_random_u32();
604 
605 			info->control.flags |= IEEE80211_TX_CTRL_NO_SEQNO;
606 			hdr->seq_ctrl =
607 				cpu_to_le16(IEEE80211_SN_TO_SEQ(sn));
608 		}
609 		IEEE80211_SKB_CB(skb)->flags |= tx_flags;
610 		ieee80211_tx_skb_tid_band(sdata, skb, 7, channel->band);
611 	}
612 }
613 
614 static void ieee80211_scan_state_send_probe(struct ieee80211_local *local,
615 					    unsigned long *next_delay)
616 {
617 	int i;
618 	struct ieee80211_sub_if_data *sdata;
619 	struct cfg80211_scan_request *scan_req;
620 	enum nl80211_band band = local->hw.conf.chandef.chan->band;
621 	u32 flags = 0, tx_flags;
622 
623 	scan_req = rcu_dereference_protected(local->scan_req,
624 					     lockdep_is_held(&local->mtx));
625 
626 	tx_flags = IEEE80211_TX_INTFL_OFFCHAN_TX_OK;
627 	if (scan_req->no_cck)
628 		tx_flags |= IEEE80211_TX_CTL_NO_CCK_RATE;
629 	if (scan_req->flags & NL80211_SCAN_FLAG_MIN_PREQ_CONTENT)
630 		flags |= IEEE80211_PROBE_FLAG_MIN_CONTENT;
631 	if (scan_req->flags & NL80211_SCAN_FLAG_RANDOM_SN)
632 		flags |= IEEE80211_PROBE_FLAG_RANDOM_SN;
633 
634 	sdata = rcu_dereference_protected(local->scan_sdata,
635 					  lockdep_is_held(&local->mtx));
636 
637 	for (i = 0; i < scan_req->n_ssids; i++)
638 		ieee80211_send_scan_probe_req(
639 			sdata, local->scan_addr, scan_req->bssid,
640 			scan_req->ssids[i].ssid, scan_req->ssids[i].ssid_len,
641 			scan_req->ie, scan_req->ie_len,
642 			scan_req->rates[band], flags,
643 			tx_flags, local->hw.conf.chandef.chan);
644 
645 	/*
646 	 * After sending probe requests, wait for probe responses
647 	 * on the channel.
648 	 */
649 	*next_delay = IEEE80211_CHANNEL_TIME;
650 	local->next_scan_state = SCAN_DECISION;
651 }
652 
653 static int __ieee80211_start_scan(struct ieee80211_sub_if_data *sdata,
654 				  struct cfg80211_scan_request *req)
655 {
656 	struct ieee80211_local *local = sdata->local;
657 	bool hw_scan = local->ops->hw_scan;
658 	int rc;
659 
660 	lockdep_assert_held(&local->mtx);
661 
662 	if (local->scan_req)
663 		return -EBUSY;
664 
665 	if (!__ieee80211_can_leave_ch(sdata))
666 		return -EBUSY;
667 
668 	if (!ieee80211_can_scan(local, sdata)) {
669 		/* wait for the work to finish/time out */
670 		rcu_assign_pointer(local->scan_req, req);
671 		rcu_assign_pointer(local->scan_sdata, sdata);
672 		return 0;
673 	}
674 
675  again:
676 	if (hw_scan) {
677 		u8 *ies;
678 
679 		local->hw_scan_ies_bufsize = local->scan_ies_len + req->ie_len;
680 
681 		if (ieee80211_hw_check(&local->hw, SINGLE_SCAN_ON_ALL_BANDS)) {
682 			int i, n_bands = 0;
683 			u8 bands_counted = 0;
684 
685 			for (i = 0; i < req->n_channels; i++) {
686 				if (bands_counted & BIT(req->channels[i]->band))
687 					continue;
688 				bands_counted |= BIT(req->channels[i]->band);
689 				n_bands++;
690 			}
691 
692 			local->hw_scan_ies_bufsize *= n_bands;
693 		}
694 
695 		local->hw_scan_req = kmalloc(
696 				sizeof(*local->hw_scan_req) +
697 				req->n_channels * sizeof(req->channels[0]) +
698 				local->hw_scan_ies_bufsize, GFP_KERNEL);
699 		if (!local->hw_scan_req)
700 			return -ENOMEM;
701 
702 		local->hw_scan_req->req.ssids = req->ssids;
703 		local->hw_scan_req->req.n_ssids = req->n_ssids;
704 		ies = (u8 *)local->hw_scan_req +
705 			sizeof(*local->hw_scan_req) +
706 			req->n_channels * sizeof(req->channels[0]);
707 		local->hw_scan_req->req.ie = ies;
708 		local->hw_scan_req->req.flags = req->flags;
709 		eth_broadcast_addr(local->hw_scan_req->req.bssid);
710 		local->hw_scan_req->req.duration = req->duration;
711 		local->hw_scan_req->req.duration_mandatory =
712 			req->duration_mandatory;
713 
714 		local->hw_scan_band = 0;
715 
716 		/*
717 		 * After allocating local->hw_scan_req, we must
718 		 * go through until ieee80211_prep_hw_scan(), so
719 		 * anything that might be changed here and leave
720 		 * this function early must not go after this
721 		 * allocation.
722 		 */
723 	}
724 
725 	rcu_assign_pointer(local->scan_req, req);
726 	rcu_assign_pointer(local->scan_sdata, sdata);
727 
728 	if (req->flags & NL80211_SCAN_FLAG_RANDOM_ADDR)
729 		get_random_mask_addr(local->scan_addr,
730 				     req->mac_addr,
731 				     req->mac_addr_mask);
732 	else
733 		memcpy(local->scan_addr, sdata->vif.addr, ETH_ALEN);
734 
735 	if (hw_scan) {
736 		__set_bit(SCAN_HW_SCANNING, &local->scanning);
737 	} else if ((req->n_channels == 1) &&
738 		   (req->channels[0] == local->_oper_chandef.chan)) {
739 		/*
740 		 * If we are scanning only on the operating channel
741 		 * then we do not need to stop normal activities
742 		 */
743 		unsigned long next_delay;
744 
745 		__set_bit(SCAN_ONCHANNEL_SCANNING, &local->scanning);
746 
747 		ieee80211_recalc_idle(local);
748 
749 		/* Notify driver scan is starting, keep order of operations
750 		 * same as normal software scan, in case that matters. */
751 		drv_sw_scan_start(local, sdata, local->scan_addr);
752 
753 		ieee80211_configure_filter(local); /* accept probe-responses */
754 
755 		/* We need to ensure power level is at max for scanning. */
756 		ieee80211_hw_config(local, 0);
757 
758 		if ((req->channels[0]->flags & (IEEE80211_CHAN_NO_IR |
759 						IEEE80211_CHAN_RADAR)) ||
760 		    !req->n_ssids) {
761 			next_delay = IEEE80211_PASSIVE_CHANNEL_TIME;
762 		} else {
763 			ieee80211_scan_state_send_probe(local, &next_delay);
764 			next_delay = IEEE80211_CHANNEL_TIME;
765 		}
766 
767 		/* Now, just wait a bit and we are all done! */
768 		ieee80211_queue_delayed_work(&local->hw, &local->scan_work,
769 					     next_delay);
770 		return 0;
771 	} else {
772 		/* Do normal software scan */
773 		__set_bit(SCAN_SW_SCANNING, &local->scanning);
774 	}
775 
776 	ieee80211_recalc_idle(local);
777 
778 	if (hw_scan) {
779 		WARN_ON(!ieee80211_prep_hw_scan(sdata));
780 		rc = drv_hw_scan(local, sdata, local->hw_scan_req);
781 	} else {
782 		rc = ieee80211_start_sw_scan(local, sdata);
783 	}
784 
785 	if (rc) {
786 		kfree(local->hw_scan_req);
787 		local->hw_scan_req = NULL;
788 		local->scanning = 0;
789 
790 		ieee80211_recalc_idle(local);
791 
792 		local->scan_req = NULL;
793 		RCU_INIT_POINTER(local->scan_sdata, NULL);
794 	}
795 
796 	if (hw_scan && rc == 1) {
797 		/*
798 		 * we can't fall back to software for P2P-GO
799 		 * as it must update NoA etc.
800 		 */
801 		if (ieee80211_vif_type_p2p(&sdata->vif) ==
802 				NL80211_IFTYPE_P2P_GO)
803 			return -EOPNOTSUPP;
804 		hw_scan = false;
805 		goto again;
806 	}
807 
808 	return rc;
809 }
810 
811 static unsigned long
812 ieee80211_scan_get_channel_time(struct ieee80211_channel *chan)
813 {
814 	/*
815 	 * TODO: channel switching also consumes quite some time,
816 	 * add that delay as well to get a better estimation
817 	 */
818 	if (chan->flags & (IEEE80211_CHAN_NO_IR | IEEE80211_CHAN_RADAR))
819 		return IEEE80211_PASSIVE_CHANNEL_TIME;
820 	return IEEE80211_PROBE_DELAY + IEEE80211_CHANNEL_TIME;
821 }
822 
823 static void ieee80211_scan_state_decision(struct ieee80211_local *local,
824 					  unsigned long *next_delay)
825 {
826 	bool associated = false;
827 	bool tx_empty = true;
828 	bool bad_latency;
829 	struct ieee80211_sub_if_data *sdata;
830 	struct ieee80211_channel *next_chan;
831 	enum mac80211_scan_state next_scan_state;
832 	struct cfg80211_scan_request *scan_req;
833 
834 	/*
835 	 * check if at least one STA interface is associated,
836 	 * check if at least one STA interface has pending tx frames
837 	 * and grab the lowest used beacon interval
838 	 */
839 	mutex_lock(&local->iflist_mtx);
840 	list_for_each_entry(sdata, &local->interfaces, list) {
841 		if (!ieee80211_sdata_running(sdata))
842 			continue;
843 
844 		if (sdata->vif.type == NL80211_IFTYPE_STATION) {
845 			if (sdata->u.mgd.associated) {
846 				associated = true;
847 
848 				if (!qdisc_all_tx_empty(sdata->dev)) {
849 					tx_empty = false;
850 					break;
851 				}
852 			}
853 		}
854 	}
855 	mutex_unlock(&local->iflist_mtx);
856 
857 	scan_req = rcu_dereference_protected(local->scan_req,
858 					     lockdep_is_held(&local->mtx));
859 
860 	next_chan = scan_req->channels[local->scan_channel_idx];
861 
862 	/*
863 	 * we're currently scanning a different channel, let's
864 	 * see if we can scan another channel without interfering
865 	 * with the current traffic situation.
866 	 *
867 	 * Keep good latency, do not stay off-channel more than 125 ms.
868 	 */
869 
870 	bad_latency = time_after(jiffies +
871 				 ieee80211_scan_get_channel_time(next_chan),
872 				 local->leave_oper_channel_time + HZ / 8);
873 
874 	if (associated && !tx_empty) {
875 		if (scan_req->flags & NL80211_SCAN_FLAG_LOW_PRIORITY)
876 			next_scan_state = SCAN_ABORT;
877 		else
878 			next_scan_state = SCAN_SUSPEND;
879 	} else if (associated && bad_latency) {
880 		next_scan_state = SCAN_SUSPEND;
881 	} else {
882 		next_scan_state = SCAN_SET_CHANNEL;
883 	}
884 
885 	local->next_scan_state = next_scan_state;
886 
887 	*next_delay = 0;
888 }
889 
890 static void ieee80211_scan_state_set_channel(struct ieee80211_local *local,
891 					     unsigned long *next_delay)
892 {
893 	int skip;
894 	struct ieee80211_channel *chan;
895 	enum nl80211_bss_scan_width oper_scan_width;
896 	struct cfg80211_scan_request *scan_req;
897 
898 	scan_req = rcu_dereference_protected(local->scan_req,
899 					     lockdep_is_held(&local->mtx));
900 
901 	skip = 0;
902 	chan = scan_req->channels[local->scan_channel_idx];
903 
904 	local->scan_chandef.chan = chan;
905 	local->scan_chandef.center_freq1 = chan->center_freq;
906 	local->scan_chandef.freq1_offset = chan->freq_offset;
907 	local->scan_chandef.center_freq2 = 0;
908 	switch (scan_req->scan_width) {
909 	case NL80211_BSS_CHAN_WIDTH_5:
910 		local->scan_chandef.width = NL80211_CHAN_WIDTH_5;
911 		break;
912 	case NL80211_BSS_CHAN_WIDTH_10:
913 		local->scan_chandef.width = NL80211_CHAN_WIDTH_10;
914 		break;
915 	default:
916 	case NL80211_BSS_CHAN_WIDTH_20:
917 		/* If scanning on oper channel, use whatever channel-type
918 		 * is currently in use.
919 		 */
920 		oper_scan_width = cfg80211_chandef_to_scan_width(
921 					&local->_oper_chandef);
922 		if (chan == local->_oper_chandef.chan &&
923 		    oper_scan_width == scan_req->scan_width)
924 			local->scan_chandef = local->_oper_chandef;
925 		else
926 			local->scan_chandef.width = NL80211_CHAN_WIDTH_20_NOHT;
927 		break;
928 	}
929 
930 	if (ieee80211_hw_config(local, IEEE80211_CONF_CHANGE_CHANNEL))
931 		skip = 1;
932 
933 	/* advance state machine to next channel/band */
934 	local->scan_channel_idx++;
935 
936 	if (skip) {
937 		/* if we skip this channel return to the decision state */
938 		local->next_scan_state = SCAN_DECISION;
939 		return;
940 	}
941 
942 	/*
943 	 * Probe delay is used to update the NAV, cf. 11.1.3.2.2
944 	 * (which unfortunately doesn't say _why_ step a) is done,
945 	 * but it waits for the probe delay or until a frame is
946 	 * received - and the received frame would update the NAV).
947 	 * For now, we do not support waiting until a frame is
948 	 * received.
949 	 *
950 	 * In any case, it is not necessary for a passive scan.
951 	 */
952 	if ((chan->flags & (IEEE80211_CHAN_NO_IR | IEEE80211_CHAN_RADAR)) ||
953 	    !scan_req->n_ssids) {
954 		*next_delay = IEEE80211_PASSIVE_CHANNEL_TIME;
955 		local->next_scan_state = SCAN_DECISION;
956 		return;
957 	}
958 
959 	/* active scan, send probes */
960 	*next_delay = IEEE80211_PROBE_DELAY;
961 	local->next_scan_state = SCAN_SEND_PROBE;
962 }
963 
964 static void ieee80211_scan_state_suspend(struct ieee80211_local *local,
965 					 unsigned long *next_delay)
966 {
967 	/* switch back to the operating channel */
968 	local->scan_chandef.chan = NULL;
969 	ieee80211_hw_config(local, IEEE80211_CONF_CHANGE_CHANNEL);
970 
971 	/* disable PS */
972 	ieee80211_offchannel_return(local);
973 
974 	*next_delay = HZ / 5;
975 	/* afterwards, resume scan & go to next channel */
976 	local->next_scan_state = SCAN_RESUME;
977 }
978 
979 static void ieee80211_scan_state_resume(struct ieee80211_local *local,
980 					unsigned long *next_delay)
981 {
982 	ieee80211_offchannel_stop_vifs(local);
983 
984 	if (local->ops->flush) {
985 		ieee80211_flush_queues(local, NULL, false);
986 		*next_delay = 0;
987 	} else
988 		*next_delay = HZ / 10;
989 
990 	/* remember when we left the operating channel */
991 	local->leave_oper_channel_time = jiffies;
992 
993 	/* advance to the next channel to be scanned */
994 	local->next_scan_state = SCAN_SET_CHANNEL;
995 }
996 
997 void ieee80211_scan_work(struct work_struct *work)
998 {
999 	struct ieee80211_local *local =
1000 		container_of(work, struct ieee80211_local, scan_work.work);
1001 	struct ieee80211_sub_if_data *sdata;
1002 	struct cfg80211_scan_request *scan_req;
1003 	unsigned long next_delay = 0;
1004 	bool aborted;
1005 
1006 	mutex_lock(&local->mtx);
1007 
1008 	if (!ieee80211_can_run_worker(local)) {
1009 		aborted = true;
1010 		goto out_complete;
1011 	}
1012 
1013 	sdata = rcu_dereference_protected(local->scan_sdata,
1014 					  lockdep_is_held(&local->mtx));
1015 	scan_req = rcu_dereference_protected(local->scan_req,
1016 					     lockdep_is_held(&local->mtx));
1017 
1018 	/* When scanning on-channel, the first-callback means completed. */
1019 	if (test_bit(SCAN_ONCHANNEL_SCANNING, &local->scanning)) {
1020 		aborted = test_and_clear_bit(SCAN_ABORTED, &local->scanning);
1021 		goto out_complete;
1022 	}
1023 
1024 	if (test_and_clear_bit(SCAN_COMPLETED, &local->scanning)) {
1025 		aborted = test_and_clear_bit(SCAN_ABORTED, &local->scanning);
1026 		goto out_complete;
1027 	}
1028 
1029 	if (!sdata || !scan_req)
1030 		goto out;
1031 
1032 	if (!local->scanning) {
1033 		int rc;
1034 
1035 		RCU_INIT_POINTER(local->scan_req, NULL);
1036 		RCU_INIT_POINTER(local->scan_sdata, NULL);
1037 
1038 		rc = __ieee80211_start_scan(sdata, scan_req);
1039 		if (rc) {
1040 			/* need to complete scan in cfg80211 */
1041 			rcu_assign_pointer(local->scan_req, scan_req);
1042 			aborted = true;
1043 			goto out_complete;
1044 		} else
1045 			goto out;
1046 	}
1047 
1048 	/*
1049 	 * as long as no delay is required advance immediately
1050 	 * without scheduling a new work
1051 	 */
1052 	do {
1053 		if (!ieee80211_sdata_running(sdata)) {
1054 			aborted = true;
1055 			goto out_complete;
1056 		}
1057 
1058 		switch (local->next_scan_state) {
1059 		case SCAN_DECISION:
1060 			/* if no more bands/channels left, complete scan */
1061 			if (local->scan_channel_idx >= scan_req->n_channels) {
1062 				aborted = false;
1063 				goto out_complete;
1064 			}
1065 			ieee80211_scan_state_decision(local, &next_delay);
1066 			break;
1067 		case SCAN_SET_CHANNEL:
1068 			ieee80211_scan_state_set_channel(local, &next_delay);
1069 			break;
1070 		case SCAN_SEND_PROBE:
1071 			ieee80211_scan_state_send_probe(local, &next_delay);
1072 			break;
1073 		case SCAN_SUSPEND:
1074 			ieee80211_scan_state_suspend(local, &next_delay);
1075 			break;
1076 		case SCAN_RESUME:
1077 			ieee80211_scan_state_resume(local, &next_delay);
1078 			break;
1079 		case SCAN_ABORT:
1080 			aborted = true;
1081 			goto out_complete;
1082 		}
1083 	} while (next_delay == 0);
1084 
1085 	ieee80211_queue_delayed_work(&local->hw, &local->scan_work, next_delay);
1086 	goto out;
1087 
1088 out_complete:
1089 	__ieee80211_scan_completed(&local->hw, aborted);
1090 out:
1091 	mutex_unlock(&local->mtx);
1092 }
1093 
1094 int ieee80211_request_scan(struct ieee80211_sub_if_data *sdata,
1095 			   struct cfg80211_scan_request *req)
1096 {
1097 	int res;
1098 
1099 	mutex_lock(&sdata->local->mtx);
1100 	res = __ieee80211_start_scan(sdata, req);
1101 	mutex_unlock(&sdata->local->mtx);
1102 
1103 	return res;
1104 }
1105 
1106 int ieee80211_request_ibss_scan(struct ieee80211_sub_if_data *sdata,
1107 				const u8 *ssid, u8 ssid_len,
1108 				struct ieee80211_channel **channels,
1109 				unsigned int n_channels,
1110 				enum nl80211_bss_scan_width scan_width)
1111 {
1112 	struct ieee80211_local *local = sdata->local;
1113 	int ret = -EBUSY, i, n_ch = 0;
1114 	enum nl80211_band band;
1115 
1116 	mutex_lock(&local->mtx);
1117 
1118 	/* busy scanning */
1119 	if (local->scan_req)
1120 		goto unlock;
1121 
1122 	/* fill internal scan request */
1123 	if (!channels) {
1124 		int max_n;
1125 
1126 		for (band = 0; band < NUM_NL80211_BANDS; band++) {
1127 			if (!local->hw.wiphy->bands[band])
1128 				continue;
1129 
1130 			max_n = local->hw.wiphy->bands[band]->n_channels;
1131 			for (i = 0; i < max_n; i++) {
1132 				struct ieee80211_channel *tmp_ch =
1133 				    &local->hw.wiphy->bands[band]->channels[i];
1134 
1135 				if (tmp_ch->flags & (IEEE80211_CHAN_NO_IR |
1136 						     IEEE80211_CHAN_DISABLED))
1137 					continue;
1138 
1139 				local->int_scan_req->channels[n_ch] = tmp_ch;
1140 				n_ch++;
1141 			}
1142 		}
1143 
1144 		if (WARN_ON_ONCE(n_ch == 0))
1145 			goto unlock;
1146 
1147 		local->int_scan_req->n_channels = n_ch;
1148 	} else {
1149 		for (i = 0; i < n_channels; i++) {
1150 			if (channels[i]->flags & (IEEE80211_CHAN_NO_IR |
1151 						  IEEE80211_CHAN_DISABLED))
1152 				continue;
1153 
1154 			local->int_scan_req->channels[n_ch] = channels[i];
1155 			n_ch++;
1156 		}
1157 
1158 		if (WARN_ON_ONCE(n_ch == 0))
1159 			goto unlock;
1160 
1161 		local->int_scan_req->n_channels = n_ch;
1162 	}
1163 
1164 	local->int_scan_req->ssids = &local->scan_ssid;
1165 	local->int_scan_req->n_ssids = 1;
1166 	local->int_scan_req->scan_width = scan_width;
1167 	memcpy(local->int_scan_req->ssids[0].ssid, ssid, IEEE80211_MAX_SSID_LEN);
1168 	local->int_scan_req->ssids[0].ssid_len = ssid_len;
1169 
1170 	ret = __ieee80211_start_scan(sdata, sdata->local->int_scan_req);
1171  unlock:
1172 	mutex_unlock(&local->mtx);
1173 	return ret;
1174 }
1175 
1176 /*
1177  * Only call this function when a scan can't be queued -- under RTNL.
1178  */
1179 void ieee80211_scan_cancel(struct ieee80211_local *local)
1180 {
1181 	/*
1182 	 * We are canceling software scan, or deferred scan that was not
1183 	 * yet really started (see __ieee80211_start_scan ).
1184 	 *
1185 	 * Regarding hardware scan:
1186 	 * - we can not call  __ieee80211_scan_completed() as when
1187 	 *   SCAN_HW_SCANNING bit is set this function change
1188 	 *   local->hw_scan_req to operate on 5G band, what race with
1189 	 *   driver which can use local->hw_scan_req
1190 	 *
1191 	 * - we can not cancel scan_work since driver can schedule it
1192 	 *   by ieee80211_scan_completed(..., true) to finish scan
1193 	 *
1194 	 * Hence we only call the cancel_hw_scan() callback, but the low-level
1195 	 * driver is still responsible for calling ieee80211_scan_completed()
1196 	 * after the scan was completed/aborted.
1197 	 */
1198 
1199 	mutex_lock(&local->mtx);
1200 	if (!local->scan_req)
1201 		goto out;
1202 
1203 	/*
1204 	 * We have a scan running and the driver already reported completion,
1205 	 * but the worker hasn't run yet or is stuck on the mutex - mark it as
1206 	 * cancelled.
1207 	 */
1208 	if (test_bit(SCAN_HW_SCANNING, &local->scanning) &&
1209 	    test_bit(SCAN_COMPLETED, &local->scanning)) {
1210 		set_bit(SCAN_HW_CANCELLED, &local->scanning);
1211 		goto out;
1212 	}
1213 
1214 	if (test_bit(SCAN_HW_SCANNING, &local->scanning)) {
1215 		/*
1216 		 * Make sure that __ieee80211_scan_completed doesn't trigger a
1217 		 * scan on another band.
1218 		 */
1219 		set_bit(SCAN_HW_CANCELLED, &local->scanning);
1220 		if (local->ops->cancel_hw_scan)
1221 			drv_cancel_hw_scan(local,
1222 				rcu_dereference_protected(local->scan_sdata,
1223 						lockdep_is_held(&local->mtx)));
1224 		goto out;
1225 	}
1226 
1227 	/*
1228 	 * If the work is currently running, it must be blocked on
1229 	 * the mutex, but we'll set scan_sdata = NULL and it'll
1230 	 * simply exit once it acquires the mutex.
1231 	 */
1232 	cancel_delayed_work(&local->scan_work);
1233 	/* and clean up */
1234 	memset(&local->scan_info, 0, sizeof(local->scan_info));
1235 	__ieee80211_scan_completed(&local->hw, true);
1236 out:
1237 	mutex_unlock(&local->mtx);
1238 }
1239 
1240 int __ieee80211_request_sched_scan_start(struct ieee80211_sub_if_data *sdata,
1241 					struct cfg80211_sched_scan_request *req)
1242 {
1243 	struct ieee80211_local *local = sdata->local;
1244 	struct ieee80211_scan_ies sched_scan_ies = {};
1245 	struct cfg80211_chan_def chandef;
1246 	int ret, i, iebufsz, num_bands = 0;
1247 	u32 rate_masks[NUM_NL80211_BANDS] = {};
1248 	u8 bands_used = 0;
1249 	u8 *ie;
1250 	u32 flags = 0;
1251 
1252 	iebufsz = local->scan_ies_len + req->ie_len;
1253 
1254 	lockdep_assert_held(&local->mtx);
1255 
1256 	if (!local->ops->sched_scan_start)
1257 		return -ENOTSUPP;
1258 
1259 	for (i = 0; i < NUM_NL80211_BANDS; i++) {
1260 		if (local->hw.wiphy->bands[i]) {
1261 			bands_used |= BIT(i);
1262 			rate_masks[i] = (u32) -1;
1263 			num_bands++;
1264 		}
1265 	}
1266 
1267 	if (req->flags & NL80211_SCAN_FLAG_MIN_PREQ_CONTENT)
1268 		flags |= IEEE80211_PROBE_FLAG_MIN_CONTENT;
1269 
1270 	ie = kcalloc(iebufsz, num_bands, GFP_KERNEL);
1271 	if (!ie) {
1272 		ret = -ENOMEM;
1273 		goto out;
1274 	}
1275 
1276 	ieee80211_prepare_scan_chandef(&chandef, req->scan_width);
1277 
1278 	ieee80211_build_preq_ies(sdata, ie, num_bands * iebufsz,
1279 				 &sched_scan_ies, req->ie,
1280 				 req->ie_len, bands_used, rate_masks, &chandef,
1281 				 flags);
1282 
1283 	ret = drv_sched_scan_start(local, sdata, req, &sched_scan_ies);
1284 	if (ret == 0) {
1285 		rcu_assign_pointer(local->sched_scan_sdata, sdata);
1286 		rcu_assign_pointer(local->sched_scan_req, req);
1287 	}
1288 
1289 	kfree(ie);
1290 
1291 out:
1292 	if (ret) {
1293 		/* Clean in case of failure after HW restart or upon resume. */
1294 		RCU_INIT_POINTER(local->sched_scan_sdata, NULL);
1295 		RCU_INIT_POINTER(local->sched_scan_req, NULL);
1296 	}
1297 
1298 	return ret;
1299 }
1300 
1301 int ieee80211_request_sched_scan_start(struct ieee80211_sub_if_data *sdata,
1302 				       struct cfg80211_sched_scan_request *req)
1303 {
1304 	struct ieee80211_local *local = sdata->local;
1305 	int ret;
1306 
1307 	mutex_lock(&local->mtx);
1308 
1309 	if (rcu_access_pointer(local->sched_scan_sdata)) {
1310 		mutex_unlock(&local->mtx);
1311 		return -EBUSY;
1312 	}
1313 
1314 	ret = __ieee80211_request_sched_scan_start(sdata, req);
1315 
1316 	mutex_unlock(&local->mtx);
1317 	return ret;
1318 }
1319 
1320 int ieee80211_request_sched_scan_stop(struct ieee80211_local *local)
1321 {
1322 	struct ieee80211_sub_if_data *sched_scan_sdata;
1323 	int ret = -ENOENT;
1324 
1325 	mutex_lock(&local->mtx);
1326 
1327 	if (!local->ops->sched_scan_stop) {
1328 		ret = -ENOTSUPP;
1329 		goto out;
1330 	}
1331 
1332 	/* We don't want to restart sched scan anymore. */
1333 	RCU_INIT_POINTER(local->sched_scan_req, NULL);
1334 
1335 	sched_scan_sdata = rcu_dereference_protected(local->sched_scan_sdata,
1336 						lockdep_is_held(&local->mtx));
1337 	if (sched_scan_sdata) {
1338 		ret = drv_sched_scan_stop(local, sched_scan_sdata);
1339 		if (!ret)
1340 			RCU_INIT_POINTER(local->sched_scan_sdata, NULL);
1341 	}
1342 out:
1343 	mutex_unlock(&local->mtx);
1344 
1345 	return ret;
1346 }
1347 
1348 void ieee80211_sched_scan_results(struct ieee80211_hw *hw)
1349 {
1350 	struct ieee80211_local *local = hw_to_local(hw);
1351 
1352 	trace_api_sched_scan_results(local);
1353 
1354 	cfg80211_sched_scan_results(hw->wiphy, 0);
1355 }
1356 EXPORT_SYMBOL(ieee80211_sched_scan_results);
1357 
1358 void ieee80211_sched_scan_end(struct ieee80211_local *local)
1359 {
1360 	mutex_lock(&local->mtx);
1361 
1362 	if (!rcu_access_pointer(local->sched_scan_sdata)) {
1363 		mutex_unlock(&local->mtx);
1364 		return;
1365 	}
1366 
1367 	RCU_INIT_POINTER(local->sched_scan_sdata, NULL);
1368 
1369 	/* If sched scan was aborted by the driver. */
1370 	RCU_INIT_POINTER(local->sched_scan_req, NULL);
1371 
1372 	mutex_unlock(&local->mtx);
1373 
1374 	cfg80211_sched_scan_stopped(local->hw.wiphy, 0);
1375 }
1376 
1377 void ieee80211_sched_scan_stopped_work(struct work_struct *work)
1378 {
1379 	struct ieee80211_local *local =
1380 		container_of(work, struct ieee80211_local,
1381 			     sched_scan_stopped_work);
1382 
1383 	ieee80211_sched_scan_end(local);
1384 }
1385 
1386 void ieee80211_sched_scan_stopped(struct ieee80211_hw *hw)
1387 {
1388 	struct ieee80211_local *local = hw_to_local(hw);
1389 
1390 	trace_api_sched_scan_stopped(local);
1391 
1392 	/*
1393 	 * this shouldn't really happen, so for simplicity
1394 	 * simply ignore it, and let mac80211 reconfigure
1395 	 * the sched scan later on.
1396 	 */
1397 	if (local->in_reconfig)
1398 		return;
1399 
1400 	schedule_work(&local->sched_scan_stopped_work);
1401 }
1402 EXPORT_SYMBOL(ieee80211_sched_scan_stopped);
1403