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) 2018-2021 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 
ieee80211_rx_bss_put(struct ieee80211_local * local,struct ieee80211_bss * bss)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 
is_uapsd_supported(struct ieee802_11_elems * elems)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
ieee80211_update_bss_from_elems(struct ieee80211_local * local,struct ieee80211_bss * bss,struct ieee802_11_elems * elems,struct ieee80211_rx_status * rx_status,bool beacon)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 *
ieee80211_bss_info_update(struct ieee80211_local * local,struct ieee80211_rx_status * rx_status,struct ieee80211_mgmt * mgmt,size_t len,struct ieee80211_channel * channel)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 		      ieee80211_is_s1g_beacon(mgmt->frame_control);
151 	struct cfg80211_bss *cbss, *non_tx_cbss;
152 	struct ieee80211_bss *bss, *non_tx_bss;
153 	struct cfg80211_inform_bss bss_meta = {
154 		.boottime_ns = rx_status->boottime_ns,
155 	};
156 	bool signal_valid;
157 	struct ieee80211_sub_if_data *scan_sdata;
158 	struct ieee802_11_elems *elems;
159 	size_t baselen;
160 	u8 *elements;
161 
162 	if (rx_status->flag & RX_FLAG_NO_SIGNAL_VAL)
163 		bss_meta.signal = 0; /* invalid signal indication */
164 	else if (ieee80211_hw_check(&local->hw, SIGNAL_DBM))
165 		bss_meta.signal = rx_status->signal * 100;
166 	else if (ieee80211_hw_check(&local->hw, SIGNAL_UNSPEC))
167 		bss_meta.signal = (rx_status->signal * 100) / local->hw.max_signal;
168 
169 	bss_meta.scan_width = NL80211_BSS_CHAN_WIDTH_20;
170 	if (rx_status->bw == RATE_INFO_BW_5)
171 		bss_meta.scan_width = NL80211_BSS_CHAN_WIDTH_5;
172 	else if (rx_status->bw == RATE_INFO_BW_10)
173 		bss_meta.scan_width = NL80211_BSS_CHAN_WIDTH_10;
174 
175 	bss_meta.chan = channel;
176 
177 	rcu_read_lock();
178 	scan_sdata = rcu_dereference(local->scan_sdata);
179 	if (scan_sdata && scan_sdata->vif.type == NL80211_IFTYPE_STATION &&
180 	    scan_sdata->vif.cfg.assoc &&
181 	    ieee80211_have_rx_timestamp(rx_status)) {
182 		bss_meta.parent_tsf =
183 			ieee80211_calculate_rx_timestamp(local, rx_status,
184 							 len + FCS_LEN, 24);
185 		ether_addr_copy(bss_meta.parent_bssid,
186 				scan_sdata->vif.bss_conf.bssid);
187 	}
188 	rcu_read_unlock();
189 
190 	cbss = cfg80211_inform_bss_frame_data(local->hw.wiphy, &bss_meta,
191 					      mgmt, len, GFP_ATOMIC);
192 	if (!cbss)
193 		return NULL;
194 
195 	if (ieee80211_is_probe_resp(mgmt->frame_control)) {
196 		elements = mgmt->u.probe_resp.variable;
197 		baselen = offsetof(struct ieee80211_mgmt,
198 				   u.probe_resp.variable);
199 	} else if (ieee80211_is_s1g_beacon(mgmt->frame_control)) {
200 		struct ieee80211_ext *ext = (void *) mgmt;
201 
202 		baselen = offsetof(struct ieee80211_ext, u.s1g_beacon.variable);
203 		elements = ext->u.s1g_beacon.variable;
204 	} else {
205 		baselen = offsetof(struct ieee80211_mgmt, u.beacon.variable);
206 		elements = mgmt->u.beacon.variable;
207 	}
208 
209 	if (baselen > len)
210 		return NULL;
211 
212 	elems = ieee802_11_parse_elems(elements, len - baselen, false, cbss);
213 	if (!elems)
214 		return NULL;
215 
216 	/* In case the signal is invalid update the status */
217 	signal_valid = channel == cbss->channel;
218 	if (!signal_valid)
219 		rx_status->flag |= RX_FLAG_NO_SIGNAL_VAL;
220 
221 	bss = (void *)cbss->priv;
222 	ieee80211_update_bss_from_elems(local, bss, elems, rx_status, beacon);
223 	kfree(elems);
224 
225 	list_for_each_entry(non_tx_cbss, &cbss->nontrans_list, nontrans_list) {
226 		non_tx_bss = (void *)non_tx_cbss->priv;
227 
228 		elems = ieee802_11_parse_elems(elements, len - baselen, false,
229 					       non_tx_cbss);
230 		if (!elems)
231 			continue;
232 
233 		ieee80211_update_bss_from_elems(local, non_tx_bss, elems,
234 						rx_status, beacon);
235 		kfree(elems);
236 	}
237 
238 	return bss;
239 }
240 
ieee80211_scan_accept_presp(struct ieee80211_sub_if_data * sdata,u32 scan_flags,const u8 * da)241 static bool ieee80211_scan_accept_presp(struct ieee80211_sub_if_data *sdata,
242 					u32 scan_flags, const u8 *da)
243 {
244 	if (!sdata)
245 		return false;
246 	/* accept broadcast for OCE */
247 	if (scan_flags & NL80211_SCAN_FLAG_ACCEPT_BCAST_PROBE_RESP &&
248 	    is_broadcast_ether_addr(da))
249 		return true;
250 	if (scan_flags & NL80211_SCAN_FLAG_RANDOM_ADDR)
251 		return true;
252 	return ether_addr_equal(da, sdata->vif.addr);
253 }
254 
ieee80211_scan_rx(struct ieee80211_local * local,struct sk_buff * skb)255 void ieee80211_scan_rx(struct ieee80211_local *local, struct sk_buff *skb)
256 {
257 	struct ieee80211_rx_status *rx_status = IEEE80211_SKB_RXCB(skb);
258 	struct ieee80211_sub_if_data *sdata1, *sdata2;
259 	struct ieee80211_mgmt *mgmt = (void *)skb->data;
260 	struct ieee80211_bss *bss;
261 	struct ieee80211_channel *channel;
262 	size_t min_hdr_len = offsetof(struct ieee80211_mgmt,
263 				      u.probe_resp.variable);
264 
265 	if (!ieee80211_is_probe_resp(mgmt->frame_control) &&
266 	    !ieee80211_is_beacon(mgmt->frame_control) &&
267 	    !ieee80211_is_s1g_beacon(mgmt->frame_control))
268 		return;
269 
270 	if (ieee80211_is_s1g_beacon(mgmt->frame_control)) {
271 		if (ieee80211_is_s1g_short_beacon(mgmt->frame_control))
272 			min_hdr_len = offsetof(struct ieee80211_ext,
273 					       u.s1g_short_beacon.variable);
274 		else
275 			min_hdr_len = offsetof(struct ieee80211_ext,
276 					       u.s1g_beacon);
277 	}
278 
279 	if (skb->len < min_hdr_len)
280 		return;
281 
282 	sdata1 = rcu_dereference(local->scan_sdata);
283 	sdata2 = rcu_dereference(local->sched_scan_sdata);
284 
285 	if (likely(!sdata1 && !sdata2))
286 		return;
287 
288 	if (test_and_clear_bit(SCAN_BEACON_WAIT, &local->scanning)) {
289 		/*
290 		 * we were passive scanning because of radar/no-IR, but
291 		 * the beacon/proberesp rx gives us an opportunity to upgrade
292 		 * to active scan
293 		 */
294 		 set_bit(SCAN_BEACON_DONE, &local->scanning);
295 		 ieee80211_queue_delayed_work(&local->hw, &local->scan_work, 0);
296 	}
297 
298 	if (ieee80211_is_probe_resp(mgmt->frame_control)) {
299 		struct cfg80211_scan_request *scan_req;
300 		struct cfg80211_sched_scan_request *sched_scan_req;
301 		u32 scan_req_flags = 0, sched_scan_req_flags = 0;
302 
303 		scan_req = rcu_dereference(local->scan_req);
304 		sched_scan_req = rcu_dereference(local->sched_scan_req);
305 
306 		if (scan_req)
307 			scan_req_flags = scan_req->flags;
308 
309 		if (sched_scan_req)
310 			sched_scan_req_flags = sched_scan_req->flags;
311 
312 		/* ignore ProbeResp to foreign address or non-bcast (OCE)
313 		 * unless scanning with randomised address
314 		 */
315 		if (!ieee80211_scan_accept_presp(sdata1, scan_req_flags,
316 						 mgmt->da) &&
317 		    !ieee80211_scan_accept_presp(sdata2, sched_scan_req_flags,
318 						 mgmt->da))
319 			return;
320 	}
321 
322 	channel = ieee80211_get_channel_khz(local->hw.wiphy,
323 					ieee80211_rx_status_to_khz(rx_status));
324 
325 	if (!channel || channel->flags & IEEE80211_CHAN_DISABLED)
326 		return;
327 
328 	bss = ieee80211_bss_info_update(local, rx_status,
329 					mgmt, skb->len,
330 					channel);
331 	if (bss)
332 		ieee80211_rx_bss_put(local, bss);
333 }
334 
335 static void
ieee80211_prepare_scan_chandef(struct cfg80211_chan_def * chandef,enum nl80211_bss_scan_width scan_width)336 ieee80211_prepare_scan_chandef(struct cfg80211_chan_def *chandef,
337 			       enum nl80211_bss_scan_width scan_width)
338 {
339 	memset(chandef, 0, sizeof(*chandef));
340 	switch (scan_width) {
341 	case NL80211_BSS_CHAN_WIDTH_5:
342 		chandef->width = NL80211_CHAN_WIDTH_5;
343 		break;
344 	case NL80211_BSS_CHAN_WIDTH_10:
345 		chandef->width = NL80211_CHAN_WIDTH_10;
346 		break;
347 	default:
348 		chandef->width = NL80211_CHAN_WIDTH_20_NOHT;
349 		break;
350 	}
351 }
352 
353 /* return false if no more work */
ieee80211_prep_hw_scan(struct ieee80211_sub_if_data * sdata)354 static bool ieee80211_prep_hw_scan(struct ieee80211_sub_if_data *sdata)
355 {
356 	struct ieee80211_local *local = sdata->local;
357 	struct cfg80211_scan_request *req;
358 	struct cfg80211_chan_def chandef;
359 	u8 bands_used = 0;
360 	int i, ielen, n_chans;
361 	u32 flags = 0;
362 
363 	req = rcu_dereference_protected(local->scan_req,
364 					lockdep_is_held(&local->mtx));
365 
366 	if (test_bit(SCAN_HW_CANCELLED, &local->scanning))
367 		return false;
368 
369 	if (ieee80211_hw_check(&local->hw, SINGLE_SCAN_ON_ALL_BANDS)) {
370 		for (i = 0; i < req->n_channels; i++) {
371 			local->hw_scan_req->req.channels[i] = req->channels[i];
372 			bands_used |= BIT(req->channels[i]->band);
373 		}
374 
375 		n_chans = req->n_channels;
376 	} else {
377 		do {
378 			if (local->hw_scan_band == NUM_NL80211_BANDS)
379 				return false;
380 
381 			n_chans = 0;
382 
383 			for (i = 0; i < req->n_channels; i++) {
384 				if (req->channels[i]->band !=
385 				    local->hw_scan_band)
386 					continue;
387 				local->hw_scan_req->req.channels[n_chans] =
388 							req->channels[i];
389 				n_chans++;
390 				bands_used |= BIT(req->channels[i]->band);
391 			}
392 
393 			local->hw_scan_band++;
394 		} while (!n_chans);
395 	}
396 
397 	local->hw_scan_req->req.n_channels = n_chans;
398 	ieee80211_prepare_scan_chandef(&chandef, req->scan_width);
399 
400 	if (req->flags & NL80211_SCAN_FLAG_MIN_PREQ_CONTENT)
401 		flags |= IEEE80211_PROBE_FLAG_MIN_CONTENT;
402 
403 	ielen = ieee80211_build_preq_ies(sdata,
404 					 (u8 *)local->hw_scan_req->req.ie,
405 					 local->hw_scan_ies_bufsize,
406 					 &local->hw_scan_req->ies,
407 					 req->ie, req->ie_len,
408 					 bands_used, req->rates, &chandef,
409 					 flags);
410 	local->hw_scan_req->req.ie_len = ielen;
411 	local->hw_scan_req->req.no_cck = req->no_cck;
412 	ether_addr_copy(local->hw_scan_req->req.mac_addr, req->mac_addr);
413 	ether_addr_copy(local->hw_scan_req->req.mac_addr_mask,
414 			req->mac_addr_mask);
415 	ether_addr_copy(local->hw_scan_req->req.bssid, req->bssid);
416 
417 	return true;
418 }
419 
__ieee80211_scan_completed(struct ieee80211_hw * hw,bool aborted)420 static void __ieee80211_scan_completed(struct ieee80211_hw *hw, bool aborted)
421 {
422 	struct ieee80211_local *local = hw_to_local(hw);
423 	bool hw_scan = test_bit(SCAN_HW_SCANNING, &local->scanning);
424 	bool was_scanning = local->scanning;
425 	struct cfg80211_scan_request *scan_req;
426 	struct ieee80211_sub_if_data *scan_sdata;
427 	struct ieee80211_sub_if_data *sdata;
428 
429 	lockdep_assert_held(&local->mtx);
430 
431 	/*
432 	 * It's ok to abort a not-yet-running scan (that
433 	 * we have one at all will be verified by checking
434 	 * local->scan_req next), but not to complete it
435 	 * successfully.
436 	 */
437 	if (WARN_ON(!local->scanning && !aborted))
438 		aborted = true;
439 
440 	if (WARN_ON(!local->scan_req))
441 		return;
442 
443 	scan_sdata = rcu_dereference_protected(local->scan_sdata,
444 					       lockdep_is_held(&local->mtx));
445 
446 	if (hw_scan && !aborted &&
447 	    !ieee80211_hw_check(&local->hw, SINGLE_SCAN_ON_ALL_BANDS) &&
448 	    ieee80211_prep_hw_scan(scan_sdata)) {
449 		int rc;
450 
451 		rc = drv_hw_scan(local,
452 			rcu_dereference_protected(local->scan_sdata,
453 						  lockdep_is_held(&local->mtx)),
454 			local->hw_scan_req);
455 
456 		if (rc == 0)
457 			return;
458 
459 		/* HW scan failed and is going to be reported as aborted,
460 		 * so clear old scan info.
461 		 */
462 		memset(&local->scan_info, 0, sizeof(local->scan_info));
463 		aborted = true;
464 	}
465 
466 	kfree(local->hw_scan_req);
467 	local->hw_scan_req = NULL;
468 
469 	scan_req = rcu_dereference_protected(local->scan_req,
470 					     lockdep_is_held(&local->mtx));
471 
472 	RCU_INIT_POINTER(local->scan_req, NULL);
473 	RCU_INIT_POINTER(local->scan_sdata, NULL);
474 
475 	local->scanning = 0;
476 	local->scan_chandef.chan = NULL;
477 
478 	synchronize_rcu();
479 
480 	if (scan_req != local->int_scan_req) {
481 		local->scan_info.aborted = aborted;
482 		cfg80211_scan_done(scan_req, &local->scan_info);
483 	}
484 
485 	/* Set power back to normal operating levels. */
486 	ieee80211_hw_config(local, 0);
487 
488 	if (!hw_scan && was_scanning) {
489 		ieee80211_configure_filter(local);
490 		drv_sw_scan_complete(local, scan_sdata);
491 		ieee80211_offchannel_return(local);
492 	}
493 
494 	ieee80211_recalc_idle(local);
495 
496 	ieee80211_mlme_notify_scan_completed(local);
497 	ieee80211_ibss_notify_scan_completed(local);
498 
499 	/* Requeue all the work that might have been ignored while
500 	 * the scan was in progress; if there was none this will
501 	 * just be a no-op for the particular interface.
502 	 */
503 	list_for_each_entry_rcu(sdata, &local->interfaces, list) {
504 		if (ieee80211_sdata_running(sdata))
505 			ieee80211_queue_work(&sdata->local->hw, &sdata->work);
506 	}
507 
508 	if (was_scanning)
509 		ieee80211_start_next_roc(local);
510 }
511 
ieee80211_scan_completed(struct ieee80211_hw * hw,struct cfg80211_scan_info * info)512 void ieee80211_scan_completed(struct ieee80211_hw *hw,
513 			      struct cfg80211_scan_info *info)
514 {
515 	struct ieee80211_local *local = hw_to_local(hw);
516 
517 	trace_api_scan_completed(local, info->aborted);
518 
519 	set_bit(SCAN_COMPLETED, &local->scanning);
520 	if (info->aborted)
521 		set_bit(SCAN_ABORTED, &local->scanning);
522 
523 	memcpy(&local->scan_info, info, sizeof(*info));
524 
525 	ieee80211_queue_delayed_work(&local->hw, &local->scan_work, 0);
526 }
527 EXPORT_SYMBOL(ieee80211_scan_completed);
528 
ieee80211_start_sw_scan(struct ieee80211_local * local,struct ieee80211_sub_if_data * sdata)529 static int ieee80211_start_sw_scan(struct ieee80211_local *local,
530 				   struct ieee80211_sub_if_data *sdata)
531 {
532 	/* Software scan is not supported in multi-channel cases */
533 	if (local->use_chanctx)
534 		return -EOPNOTSUPP;
535 
536 	/*
537 	 * Hardware/driver doesn't support hw_scan, so use software
538 	 * scanning instead. First send a nullfunc frame with power save
539 	 * bit on so that AP will buffer the frames for us while we are not
540 	 * listening, then send probe requests to each channel and wait for
541 	 * the responses. After all channels are scanned, tune back to the
542 	 * original channel and send a nullfunc frame with power save bit
543 	 * off to trigger the AP to send us all the buffered frames.
544 	 *
545 	 * Note that while local->sw_scanning is true everything else but
546 	 * nullfunc frames and probe requests will be dropped in
547 	 * ieee80211_tx_h_check_assoc().
548 	 */
549 	drv_sw_scan_start(local, sdata, local->scan_addr);
550 
551 	local->leave_oper_channel_time = jiffies;
552 	local->next_scan_state = SCAN_DECISION;
553 	local->scan_channel_idx = 0;
554 
555 	ieee80211_offchannel_stop_vifs(local);
556 
557 	/* ensure nullfunc is transmitted before leaving operating channel */
558 	ieee80211_flush_queues(local, NULL, false);
559 
560 	ieee80211_configure_filter(local);
561 
562 	/* We need to set power level at maximum rate for scanning. */
563 	ieee80211_hw_config(local, 0);
564 
565 	ieee80211_queue_delayed_work(&local->hw,
566 				     &local->scan_work, 0);
567 
568 	return 0;
569 }
570 
__ieee80211_can_leave_ch(struct ieee80211_sub_if_data * sdata)571 static bool __ieee80211_can_leave_ch(struct ieee80211_sub_if_data *sdata)
572 {
573 	struct ieee80211_local *local = sdata->local;
574 	struct ieee80211_sub_if_data *sdata_iter;
575 
576 	if (!ieee80211_is_radar_required(local))
577 		return true;
578 
579 	if (!regulatory_pre_cac_allowed(local->hw.wiphy))
580 		return false;
581 
582 	mutex_lock(&local->iflist_mtx);
583 	list_for_each_entry(sdata_iter, &local->interfaces, list) {
584 		if (sdata_iter->wdev.cac_started) {
585 			mutex_unlock(&local->iflist_mtx);
586 			return false;
587 		}
588 	}
589 	mutex_unlock(&local->iflist_mtx);
590 
591 	return true;
592 }
593 
ieee80211_can_scan(struct ieee80211_local * local,struct ieee80211_sub_if_data * sdata)594 static bool ieee80211_can_scan(struct ieee80211_local *local,
595 			       struct ieee80211_sub_if_data *sdata)
596 {
597 	if (!__ieee80211_can_leave_ch(sdata))
598 		return false;
599 
600 	if (!list_empty(&local->roc_list))
601 		return false;
602 
603 	if (sdata->vif.type == NL80211_IFTYPE_STATION &&
604 	    sdata->u.mgd.flags & IEEE80211_STA_CONNECTION_POLL)
605 		return false;
606 
607 	return true;
608 }
609 
ieee80211_run_deferred_scan(struct ieee80211_local * local)610 void ieee80211_run_deferred_scan(struct ieee80211_local *local)
611 {
612 	lockdep_assert_held(&local->mtx);
613 
614 	if (!local->scan_req || local->scanning)
615 		return;
616 
617 	if (!ieee80211_can_scan(local,
618 				rcu_dereference_protected(
619 					local->scan_sdata,
620 					lockdep_is_held(&local->mtx))))
621 		return;
622 
623 	ieee80211_queue_delayed_work(&local->hw, &local->scan_work,
624 				     round_jiffies_relative(0));
625 }
626 
ieee80211_send_scan_probe_req(struct ieee80211_sub_if_data * sdata,const u8 * src,const u8 * dst,const u8 * ssid,size_t ssid_len,const u8 * ie,size_t ie_len,u32 ratemask,u32 flags,u32 tx_flags,struct ieee80211_channel * channel)627 static void ieee80211_send_scan_probe_req(struct ieee80211_sub_if_data *sdata,
628 					  const u8 *src, const u8 *dst,
629 					  const u8 *ssid, size_t ssid_len,
630 					  const u8 *ie, size_t ie_len,
631 					  u32 ratemask, u32 flags, u32 tx_flags,
632 					  struct ieee80211_channel *channel)
633 {
634 	struct sk_buff *skb;
635 
636 	skb = ieee80211_build_probe_req(sdata, src, dst, ratemask, channel,
637 					ssid, ssid_len,
638 					ie, ie_len, flags);
639 
640 	if (skb) {
641 		if (flags & IEEE80211_PROBE_FLAG_RANDOM_SN) {
642 			struct ieee80211_hdr *hdr = (void *)skb->data;
643 			struct ieee80211_tx_info *info = IEEE80211_SKB_CB(skb);
644 			u16 sn = get_random_u16();
645 
646 			info->control.flags |= IEEE80211_TX_CTRL_NO_SEQNO;
647 			hdr->seq_ctrl =
648 				cpu_to_le16(IEEE80211_SN_TO_SEQ(sn));
649 		}
650 		IEEE80211_SKB_CB(skb)->flags |= tx_flags;
651 		ieee80211_tx_skb_tid_band(sdata, skb, 7, channel->band);
652 	}
653 }
654 
ieee80211_scan_state_send_probe(struct ieee80211_local * local,unsigned long * next_delay)655 static void ieee80211_scan_state_send_probe(struct ieee80211_local *local,
656 					    unsigned long *next_delay)
657 {
658 	int i;
659 	struct ieee80211_sub_if_data *sdata;
660 	struct cfg80211_scan_request *scan_req;
661 	enum nl80211_band band = local->hw.conf.chandef.chan->band;
662 	u32 flags = 0, tx_flags;
663 
664 	scan_req = rcu_dereference_protected(local->scan_req,
665 					     lockdep_is_held(&local->mtx));
666 
667 	tx_flags = IEEE80211_TX_INTFL_OFFCHAN_TX_OK;
668 	if (scan_req->no_cck)
669 		tx_flags |= IEEE80211_TX_CTL_NO_CCK_RATE;
670 	if (scan_req->flags & NL80211_SCAN_FLAG_MIN_PREQ_CONTENT)
671 		flags |= IEEE80211_PROBE_FLAG_MIN_CONTENT;
672 	if (scan_req->flags & NL80211_SCAN_FLAG_RANDOM_SN)
673 		flags |= IEEE80211_PROBE_FLAG_RANDOM_SN;
674 
675 	sdata = rcu_dereference_protected(local->scan_sdata,
676 					  lockdep_is_held(&local->mtx));
677 
678 	for (i = 0; i < scan_req->n_ssids; i++)
679 		ieee80211_send_scan_probe_req(
680 			sdata, local->scan_addr, scan_req->bssid,
681 			scan_req->ssids[i].ssid, scan_req->ssids[i].ssid_len,
682 			scan_req->ie, scan_req->ie_len,
683 			scan_req->rates[band], flags,
684 			tx_flags, local->hw.conf.chandef.chan);
685 
686 	/*
687 	 * After sending probe requests, wait for probe responses
688 	 * on the channel.
689 	 */
690 	*next_delay = IEEE80211_CHANNEL_TIME;
691 	local->next_scan_state = SCAN_DECISION;
692 }
693 
__ieee80211_start_scan(struct ieee80211_sub_if_data * sdata,struct cfg80211_scan_request * req)694 static int __ieee80211_start_scan(struct ieee80211_sub_if_data *sdata,
695 				  struct cfg80211_scan_request *req)
696 {
697 	struct ieee80211_local *local = sdata->local;
698 	bool hw_scan = local->ops->hw_scan;
699 	int rc;
700 
701 	lockdep_assert_held(&local->mtx);
702 
703 	if (local->scan_req)
704 		return -EBUSY;
705 
706 	if (!__ieee80211_can_leave_ch(sdata))
707 		return -EBUSY;
708 
709 	if (!ieee80211_can_scan(local, sdata)) {
710 		/* wait for the work to finish/time out */
711 		rcu_assign_pointer(local->scan_req, req);
712 		rcu_assign_pointer(local->scan_sdata, sdata);
713 		return 0;
714 	}
715 
716  again:
717 	if (hw_scan) {
718 		u8 *ies;
719 
720 		local->hw_scan_ies_bufsize = local->scan_ies_len + req->ie_len;
721 
722 		if (ieee80211_hw_check(&local->hw, SINGLE_SCAN_ON_ALL_BANDS)) {
723 			int i, n_bands = 0;
724 			u8 bands_counted = 0;
725 
726 			for (i = 0; i < req->n_channels; i++) {
727 				if (bands_counted & BIT(req->channels[i]->band))
728 					continue;
729 				bands_counted |= BIT(req->channels[i]->band);
730 				n_bands++;
731 			}
732 
733 			local->hw_scan_ies_bufsize *= n_bands;
734 		}
735 
736 		local->hw_scan_req = kmalloc(
737 				sizeof(*local->hw_scan_req) +
738 				req->n_channels * sizeof(req->channels[0]) +
739 				local->hw_scan_ies_bufsize, GFP_KERNEL);
740 		if (!local->hw_scan_req)
741 			return -ENOMEM;
742 
743 		local->hw_scan_req->req.ssids = req->ssids;
744 		local->hw_scan_req->req.n_ssids = req->n_ssids;
745 		ies = (u8 *)local->hw_scan_req +
746 			sizeof(*local->hw_scan_req) +
747 			req->n_channels * sizeof(req->channels[0]);
748 		local->hw_scan_req->req.ie = ies;
749 		local->hw_scan_req->req.flags = req->flags;
750 		eth_broadcast_addr(local->hw_scan_req->req.bssid);
751 		local->hw_scan_req->req.duration = req->duration;
752 		local->hw_scan_req->req.duration_mandatory =
753 			req->duration_mandatory;
754 
755 		local->hw_scan_band = 0;
756 		local->hw_scan_req->req.n_6ghz_params = req->n_6ghz_params;
757 		local->hw_scan_req->req.scan_6ghz_params =
758 			req->scan_6ghz_params;
759 		local->hw_scan_req->req.scan_6ghz = req->scan_6ghz;
760 
761 		/*
762 		 * After allocating local->hw_scan_req, we must
763 		 * go through until ieee80211_prep_hw_scan(), so
764 		 * anything that might be changed here and leave
765 		 * this function early must not go after this
766 		 * allocation.
767 		 */
768 	}
769 
770 	rcu_assign_pointer(local->scan_req, req);
771 	rcu_assign_pointer(local->scan_sdata, sdata);
772 
773 	if (req->flags & NL80211_SCAN_FLAG_RANDOM_ADDR)
774 		get_random_mask_addr(local->scan_addr,
775 				     req->mac_addr,
776 				     req->mac_addr_mask);
777 	else
778 		memcpy(local->scan_addr, sdata->vif.addr, ETH_ALEN);
779 
780 	if (hw_scan) {
781 		__set_bit(SCAN_HW_SCANNING, &local->scanning);
782 	} else if ((req->n_channels == 1) &&
783 		   (req->channels[0] == local->_oper_chandef.chan)) {
784 		/*
785 		 * If we are scanning only on the operating channel
786 		 * then we do not need to stop normal activities
787 		 */
788 		unsigned long next_delay;
789 
790 		__set_bit(SCAN_ONCHANNEL_SCANNING, &local->scanning);
791 
792 		ieee80211_recalc_idle(local);
793 
794 		/* Notify driver scan is starting, keep order of operations
795 		 * same as normal software scan, in case that matters. */
796 		drv_sw_scan_start(local, sdata, local->scan_addr);
797 
798 		ieee80211_configure_filter(local); /* accept probe-responses */
799 
800 		/* We need to ensure power level is at max for scanning. */
801 		ieee80211_hw_config(local, 0);
802 
803 		if ((req->channels[0]->flags & (IEEE80211_CHAN_NO_IR |
804 						IEEE80211_CHAN_RADAR)) ||
805 		    !req->n_ssids) {
806 			next_delay = IEEE80211_PASSIVE_CHANNEL_TIME;
807 			if (req->n_ssids)
808 				set_bit(SCAN_BEACON_WAIT, &local->scanning);
809 		} else {
810 			ieee80211_scan_state_send_probe(local, &next_delay);
811 			next_delay = IEEE80211_CHANNEL_TIME;
812 		}
813 
814 		/* Now, just wait a bit and we are all done! */
815 		ieee80211_queue_delayed_work(&local->hw, &local->scan_work,
816 					     next_delay);
817 		return 0;
818 	} else {
819 		/* Do normal software scan */
820 		__set_bit(SCAN_SW_SCANNING, &local->scanning);
821 	}
822 
823 	ieee80211_recalc_idle(local);
824 
825 	if (hw_scan) {
826 		WARN_ON(!ieee80211_prep_hw_scan(sdata));
827 		rc = drv_hw_scan(local, sdata, local->hw_scan_req);
828 	} else {
829 		rc = ieee80211_start_sw_scan(local, sdata);
830 	}
831 
832 	if (rc) {
833 		kfree(local->hw_scan_req);
834 		local->hw_scan_req = NULL;
835 		local->scanning = 0;
836 
837 		ieee80211_recalc_idle(local);
838 
839 		local->scan_req = NULL;
840 		RCU_INIT_POINTER(local->scan_sdata, NULL);
841 	}
842 
843 	if (hw_scan && rc == 1) {
844 		/*
845 		 * we can't fall back to software for P2P-GO
846 		 * as it must update NoA etc.
847 		 */
848 		if (ieee80211_vif_type_p2p(&sdata->vif) ==
849 				NL80211_IFTYPE_P2P_GO)
850 			return -EOPNOTSUPP;
851 		hw_scan = false;
852 		goto again;
853 	}
854 
855 	return rc;
856 }
857 
858 static unsigned long
ieee80211_scan_get_channel_time(struct ieee80211_channel * chan)859 ieee80211_scan_get_channel_time(struct ieee80211_channel *chan)
860 {
861 	/*
862 	 * TODO: channel switching also consumes quite some time,
863 	 * add that delay as well to get a better estimation
864 	 */
865 	if (chan->flags & (IEEE80211_CHAN_NO_IR | IEEE80211_CHAN_RADAR))
866 		return IEEE80211_PASSIVE_CHANNEL_TIME;
867 	return IEEE80211_PROBE_DELAY + IEEE80211_CHANNEL_TIME;
868 }
869 
ieee80211_scan_state_decision(struct ieee80211_local * local,unsigned long * next_delay)870 static void ieee80211_scan_state_decision(struct ieee80211_local *local,
871 					  unsigned long *next_delay)
872 {
873 	bool associated = false;
874 	bool tx_empty = true;
875 	bool bad_latency;
876 	struct ieee80211_sub_if_data *sdata;
877 	struct ieee80211_channel *next_chan;
878 	enum mac80211_scan_state next_scan_state;
879 	struct cfg80211_scan_request *scan_req;
880 
881 	/*
882 	 * check if at least one STA interface is associated,
883 	 * check if at least one STA interface has pending tx frames
884 	 * and grab the lowest used beacon interval
885 	 */
886 	mutex_lock(&local->iflist_mtx);
887 	list_for_each_entry(sdata, &local->interfaces, list) {
888 		if (!ieee80211_sdata_running(sdata))
889 			continue;
890 
891 		if (sdata->vif.type == NL80211_IFTYPE_STATION) {
892 			if (sdata->u.mgd.associated) {
893 				associated = true;
894 
895 				if (!qdisc_all_tx_empty(sdata->dev)) {
896 					tx_empty = false;
897 					break;
898 				}
899 			}
900 		}
901 	}
902 	mutex_unlock(&local->iflist_mtx);
903 
904 	scan_req = rcu_dereference_protected(local->scan_req,
905 					     lockdep_is_held(&local->mtx));
906 
907 	next_chan = scan_req->channels[local->scan_channel_idx];
908 
909 	/*
910 	 * we're currently scanning a different channel, let's
911 	 * see if we can scan another channel without interfering
912 	 * with the current traffic situation.
913 	 *
914 	 * Keep good latency, do not stay off-channel more than 125 ms.
915 	 */
916 
917 	bad_latency = time_after(jiffies +
918 				 ieee80211_scan_get_channel_time(next_chan),
919 				 local->leave_oper_channel_time + HZ / 8);
920 
921 	if (associated && !tx_empty) {
922 		if (scan_req->flags & NL80211_SCAN_FLAG_LOW_PRIORITY)
923 			next_scan_state = SCAN_ABORT;
924 		else
925 			next_scan_state = SCAN_SUSPEND;
926 	} else if (associated && bad_latency) {
927 		next_scan_state = SCAN_SUSPEND;
928 	} else {
929 		next_scan_state = SCAN_SET_CHANNEL;
930 	}
931 
932 	local->next_scan_state = next_scan_state;
933 
934 	*next_delay = 0;
935 }
936 
ieee80211_scan_state_set_channel(struct ieee80211_local * local,unsigned long * next_delay)937 static void ieee80211_scan_state_set_channel(struct ieee80211_local *local,
938 					     unsigned long *next_delay)
939 {
940 	int skip;
941 	struct ieee80211_channel *chan;
942 	enum nl80211_bss_scan_width oper_scan_width;
943 	struct cfg80211_scan_request *scan_req;
944 
945 	scan_req = rcu_dereference_protected(local->scan_req,
946 					     lockdep_is_held(&local->mtx));
947 
948 	skip = 0;
949 	chan = scan_req->channels[local->scan_channel_idx];
950 
951 	local->scan_chandef.chan = chan;
952 	local->scan_chandef.center_freq1 = chan->center_freq;
953 	local->scan_chandef.freq1_offset = chan->freq_offset;
954 	local->scan_chandef.center_freq2 = 0;
955 
956 	/* For scanning on the S1G band, ignore scan_width (which is constant
957 	 * across all channels) for now since channel width is specific to each
958 	 * channel. Detect the required channel width here and likely revisit
959 	 * later. Maybe scan_width could be used to build the channel scan list?
960 	 */
961 	if (chan->band == NL80211_BAND_S1GHZ) {
962 		local->scan_chandef.width = ieee80211_s1g_channel_width(chan);
963 		goto set_channel;
964 	}
965 
966 	switch (scan_req->scan_width) {
967 	case NL80211_BSS_CHAN_WIDTH_5:
968 		local->scan_chandef.width = NL80211_CHAN_WIDTH_5;
969 		break;
970 	case NL80211_BSS_CHAN_WIDTH_10:
971 		local->scan_chandef.width = NL80211_CHAN_WIDTH_10;
972 		break;
973 	default:
974 	case NL80211_BSS_CHAN_WIDTH_20:
975 		/* If scanning on oper channel, use whatever channel-type
976 		 * is currently in use.
977 		 */
978 		oper_scan_width = cfg80211_chandef_to_scan_width(
979 					&local->_oper_chandef);
980 		if (chan == local->_oper_chandef.chan &&
981 		    oper_scan_width == scan_req->scan_width)
982 			local->scan_chandef = local->_oper_chandef;
983 		else
984 			local->scan_chandef.width = NL80211_CHAN_WIDTH_20_NOHT;
985 		break;
986 	case NL80211_BSS_CHAN_WIDTH_1:
987 	case NL80211_BSS_CHAN_WIDTH_2:
988 		/* shouldn't get here, S1G handled above */
989 		WARN_ON(1);
990 		break;
991 	}
992 
993 set_channel:
994 	if (ieee80211_hw_config(local, IEEE80211_CONF_CHANGE_CHANNEL))
995 		skip = 1;
996 
997 	/* advance state machine to next channel/band */
998 	local->scan_channel_idx++;
999 
1000 	if (skip) {
1001 		/* if we skip this channel return to the decision state */
1002 		local->next_scan_state = SCAN_DECISION;
1003 		return;
1004 	}
1005 
1006 	/*
1007 	 * Probe delay is used to update the NAV, cf. 11.1.3.2.2
1008 	 * (which unfortunately doesn't say _why_ step a) is done,
1009 	 * but it waits for the probe delay or until a frame is
1010 	 * received - and the received frame would update the NAV).
1011 	 * For now, we do not support waiting until a frame is
1012 	 * received.
1013 	 *
1014 	 * In any case, it is not necessary for a passive scan.
1015 	 */
1016 	if ((chan->flags & (IEEE80211_CHAN_NO_IR | IEEE80211_CHAN_RADAR)) ||
1017 	    !scan_req->n_ssids) {
1018 		*next_delay = IEEE80211_PASSIVE_CHANNEL_TIME;
1019 		local->next_scan_state = SCAN_DECISION;
1020 		if (scan_req->n_ssids)
1021 			set_bit(SCAN_BEACON_WAIT, &local->scanning);
1022 		return;
1023 	}
1024 
1025 	/* active scan, send probes */
1026 	*next_delay = IEEE80211_PROBE_DELAY;
1027 	local->next_scan_state = SCAN_SEND_PROBE;
1028 }
1029 
ieee80211_scan_state_suspend(struct ieee80211_local * local,unsigned long * next_delay)1030 static void ieee80211_scan_state_suspend(struct ieee80211_local *local,
1031 					 unsigned long *next_delay)
1032 {
1033 	/* switch back to the operating channel */
1034 	local->scan_chandef.chan = NULL;
1035 	ieee80211_hw_config(local, IEEE80211_CONF_CHANGE_CHANNEL);
1036 
1037 	/* disable PS */
1038 	ieee80211_offchannel_return(local);
1039 
1040 	*next_delay = HZ / 5;
1041 	/* afterwards, resume scan & go to next channel */
1042 	local->next_scan_state = SCAN_RESUME;
1043 }
1044 
ieee80211_scan_state_resume(struct ieee80211_local * local,unsigned long * next_delay)1045 static void ieee80211_scan_state_resume(struct ieee80211_local *local,
1046 					unsigned long *next_delay)
1047 {
1048 	ieee80211_offchannel_stop_vifs(local);
1049 
1050 	if (local->ops->flush) {
1051 		ieee80211_flush_queues(local, NULL, false);
1052 		*next_delay = 0;
1053 	} else
1054 		*next_delay = HZ / 10;
1055 
1056 	/* remember when we left the operating channel */
1057 	local->leave_oper_channel_time = jiffies;
1058 
1059 	/* advance to the next channel to be scanned */
1060 	local->next_scan_state = SCAN_SET_CHANNEL;
1061 }
1062 
ieee80211_scan_work(struct work_struct * work)1063 void ieee80211_scan_work(struct work_struct *work)
1064 {
1065 	struct ieee80211_local *local =
1066 		container_of(work, struct ieee80211_local, scan_work.work);
1067 	struct ieee80211_sub_if_data *sdata;
1068 	struct cfg80211_scan_request *scan_req;
1069 	unsigned long next_delay = 0;
1070 	bool aborted;
1071 
1072 	mutex_lock(&local->mtx);
1073 
1074 	if (!ieee80211_can_run_worker(local)) {
1075 		aborted = true;
1076 		goto out_complete;
1077 	}
1078 
1079 	sdata = rcu_dereference_protected(local->scan_sdata,
1080 					  lockdep_is_held(&local->mtx));
1081 	scan_req = rcu_dereference_protected(local->scan_req,
1082 					     lockdep_is_held(&local->mtx));
1083 
1084 	/* When scanning on-channel, the first-callback means completed. */
1085 	if (test_bit(SCAN_ONCHANNEL_SCANNING, &local->scanning)) {
1086 		aborted = test_and_clear_bit(SCAN_ABORTED, &local->scanning);
1087 		goto out_complete;
1088 	}
1089 
1090 	if (test_and_clear_bit(SCAN_COMPLETED, &local->scanning)) {
1091 		aborted = test_and_clear_bit(SCAN_ABORTED, &local->scanning);
1092 		goto out_complete;
1093 	}
1094 
1095 	if (!sdata || !scan_req)
1096 		goto out;
1097 
1098 	if (!local->scanning) {
1099 		int rc;
1100 
1101 		RCU_INIT_POINTER(local->scan_req, NULL);
1102 		RCU_INIT_POINTER(local->scan_sdata, NULL);
1103 
1104 		rc = __ieee80211_start_scan(sdata, scan_req);
1105 		if (rc) {
1106 			/* need to complete scan in cfg80211 */
1107 			rcu_assign_pointer(local->scan_req, scan_req);
1108 			aborted = true;
1109 			goto out_complete;
1110 		} else
1111 			goto out;
1112 	}
1113 
1114 	clear_bit(SCAN_BEACON_WAIT, &local->scanning);
1115 
1116 	/*
1117 	 * as long as no delay is required advance immediately
1118 	 * without scheduling a new work
1119 	 */
1120 	do {
1121 		if (!ieee80211_sdata_running(sdata)) {
1122 			aborted = true;
1123 			goto out_complete;
1124 		}
1125 
1126 		if (test_and_clear_bit(SCAN_BEACON_DONE, &local->scanning) &&
1127 		    local->next_scan_state == SCAN_DECISION)
1128 			local->next_scan_state = SCAN_SEND_PROBE;
1129 
1130 		switch (local->next_scan_state) {
1131 		case SCAN_DECISION:
1132 			/* if no more bands/channels left, complete scan */
1133 			if (local->scan_channel_idx >= scan_req->n_channels) {
1134 				aborted = false;
1135 				goto out_complete;
1136 			}
1137 			ieee80211_scan_state_decision(local, &next_delay);
1138 			break;
1139 		case SCAN_SET_CHANNEL:
1140 			ieee80211_scan_state_set_channel(local, &next_delay);
1141 			break;
1142 		case SCAN_SEND_PROBE:
1143 			ieee80211_scan_state_send_probe(local, &next_delay);
1144 			break;
1145 		case SCAN_SUSPEND:
1146 			ieee80211_scan_state_suspend(local, &next_delay);
1147 			break;
1148 		case SCAN_RESUME:
1149 			ieee80211_scan_state_resume(local, &next_delay);
1150 			break;
1151 		case SCAN_ABORT:
1152 			aborted = true;
1153 			goto out_complete;
1154 		}
1155 	} while (next_delay == 0);
1156 
1157 	ieee80211_queue_delayed_work(&local->hw, &local->scan_work, next_delay);
1158 	goto out;
1159 
1160 out_complete:
1161 	__ieee80211_scan_completed(&local->hw, aborted);
1162 out:
1163 	mutex_unlock(&local->mtx);
1164 }
1165 
ieee80211_request_scan(struct ieee80211_sub_if_data * sdata,struct cfg80211_scan_request * req)1166 int ieee80211_request_scan(struct ieee80211_sub_if_data *sdata,
1167 			   struct cfg80211_scan_request *req)
1168 {
1169 	int res;
1170 
1171 	mutex_lock(&sdata->local->mtx);
1172 	res = __ieee80211_start_scan(sdata, req);
1173 	mutex_unlock(&sdata->local->mtx);
1174 
1175 	return res;
1176 }
1177 
ieee80211_request_ibss_scan(struct ieee80211_sub_if_data * sdata,const u8 * ssid,u8 ssid_len,struct ieee80211_channel ** channels,unsigned int n_channels,enum nl80211_bss_scan_width scan_width)1178 int ieee80211_request_ibss_scan(struct ieee80211_sub_if_data *sdata,
1179 				const u8 *ssid, u8 ssid_len,
1180 				struct ieee80211_channel **channels,
1181 				unsigned int n_channels,
1182 				enum nl80211_bss_scan_width scan_width)
1183 {
1184 	struct ieee80211_local *local = sdata->local;
1185 	int ret = -EBUSY, i, n_ch = 0;
1186 	enum nl80211_band band;
1187 
1188 	mutex_lock(&local->mtx);
1189 
1190 	/* busy scanning */
1191 	if (local->scan_req)
1192 		goto unlock;
1193 
1194 	/* fill internal scan request */
1195 	if (!channels) {
1196 		int max_n;
1197 
1198 		for (band = 0; band < NUM_NL80211_BANDS; band++) {
1199 			if (!local->hw.wiphy->bands[band] ||
1200 			    band == NL80211_BAND_6GHZ)
1201 				continue;
1202 
1203 			max_n = local->hw.wiphy->bands[band]->n_channels;
1204 			for (i = 0; i < max_n; i++) {
1205 				struct ieee80211_channel *tmp_ch =
1206 				    &local->hw.wiphy->bands[band]->channels[i];
1207 
1208 				if (tmp_ch->flags & (IEEE80211_CHAN_NO_IR |
1209 						     IEEE80211_CHAN_DISABLED))
1210 					continue;
1211 
1212 				local->int_scan_req->channels[n_ch] = tmp_ch;
1213 				n_ch++;
1214 			}
1215 		}
1216 
1217 		if (WARN_ON_ONCE(n_ch == 0))
1218 			goto unlock;
1219 
1220 		local->int_scan_req->n_channels = n_ch;
1221 	} else {
1222 		for (i = 0; i < n_channels; i++) {
1223 			if (channels[i]->flags & (IEEE80211_CHAN_NO_IR |
1224 						  IEEE80211_CHAN_DISABLED))
1225 				continue;
1226 
1227 			local->int_scan_req->channels[n_ch] = channels[i];
1228 			n_ch++;
1229 		}
1230 
1231 		if (WARN_ON_ONCE(n_ch == 0))
1232 			goto unlock;
1233 
1234 		local->int_scan_req->n_channels = n_ch;
1235 	}
1236 
1237 	local->int_scan_req->ssids = &local->scan_ssid;
1238 	local->int_scan_req->n_ssids = 1;
1239 	local->int_scan_req->scan_width = scan_width;
1240 	memcpy(local->int_scan_req->ssids[0].ssid, ssid, IEEE80211_MAX_SSID_LEN);
1241 	local->int_scan_req->ssids[0].ssid_len = ssid_len;
1242 
1243 	ret = __ieee80211_start_scan(sdata, sdata->local->int_scan_req);
1244  unlock:
1245 	mutex_unlock(&local->mtx);
1246 	return ret;
1247 }
1248 
1249 /*
1250  * Only call this function when a scan can't be queued -- under RTNL.
1251  */
ieee80211_scan_cancel(struct ieee80211_local * local)1252 void ieee80211_scan_cancel(struct ieee80211_local *local)
1253 {
1254 	/*
1255 	 * We are canceling software scan, or deferred scan that was not
1256 	 * yet really started (see __ieee80211_start_scan ).
1257 	 *
1258 	 * Regarding hardware scan:
1259 	 * - we can not call  __ieee80211_scan_completed() as when
1260 	 *   SCAN_HW_SCANNING bit is set this function change
1261 	 *   local->hw_scan_req to operate on 5G band, what race with
1262 	 *   driver which can use local->hw_scan_req
1263 	 *
1264 	 * - we can not cancel scan_work since driver can schedule it
1265 	 *   by ieee80211_scan_completed(..., true) to finish scan
1266 	 *
1267 	 * Hence we only call the cancel_hw_scan() callback, but the low-level
1268 	 * driver is still responsible for calling ieee80211_scan_completed()
1269 	 * after the scan was completed/aborted.
1270 	 */
1271 
1272 	mutex_lock(&local->mtx);
1273 	if (!local->scan_req)
1274 		goto out;
1275 
1276 	/*
1277 	 * We have a scan running and the driver already reported completion,
1278 	 * but the worker hasn't run yet or is stuck on the mutex - mark it as
1279 	 * cancelled.
1280 	 */
1281 	if (test_bit(SCAN_HW_SCANNING, &local->scanning) &&
1282 	    test_bit(SCAN_COMPLETED, &local->scanning)) {
1283 		set_bit(SCAN_HW_CANCELLED, &local->scanning);
1284 		goto out;
1285 	}
1286 
1287 	if (test_bit(SCAN_HW_SCANNING, &local->scanning)) {
1288 		/*
1289 		 * Make sure that __ieee80211_scan_completed doesn't trigger a
1290 		 * scan on another band.
1291 		 */
1292 		set_bit(SCAN_HW_CANCELLED, &local->scanning);
1293 		if (local->ops->cancel_hw_scan)
1294 			drv_cancel_hw_scan(local,
1295 				rcu_dereference_protected(local->scan_sdata,
1296 						lockdep_is_held(&local->mtx)));
1297 		goto out;
1298 	}
1299 
1300 	/*
1301 	 * If the work is currently running, it must be blocked on
1302 	 * the mutex, but we'll set scan_sdata = NULL and it'll
1303 	 * simply exit once it acquires the mutex.
1304 	 */
1305 	cancel_delayed_work(&local->scan_work);
1306 	/* and clean up */
1307 	memset(&local->scan_info, 0, sizeof(local->scan_info));
1308 	__ieee80211_scan_completed(&local->hw, true);
1309 out:
1310 	mutex_unlock(&local->mtx);
1311 }
1312 
__ieee80211_request_sched_scan_start(struct ieee80211_sub_if_data * sdata,struct cfg80211_sched_scan_request * req)1313 int __ieee80211_request_sched_scan_start(struct ieee80211_sub_if_data *sdata,
1314 					struct cfg80211_sched_scan_request *req)
1315 {
1316 	struct ieee80211_local *local = sdata->local;
1317 	struct ieee80211_scan_ies sched_scan_ies = {};
1318 	struct cfg80211_chan_def chandef;
1319 	int ret, i, iebufsz, num_bands = 0;
1320 	u32 rate_masks[NUM_NL80211_BANDS] = {};
1321 	u8 bands_used = 0;
1322 	u8 *ie;
1323 	u32 flags = 0;
1324 
1325 	iebufsz = local->scan_ies_len + req->ie_len;
1326 
1327 	lockdep_assert_held(&local->mtx);
1328 
1329 	if (!local->ops->sched_scan_start)
1330 		return -ENOTSUPP;
1331 
1332 	for (i = 0; i < NUM_NL80211_BANDS; i++) {
1333 		if (local->hw.wiphy->bands[i]) {
1334 			bands_used |= BIT(i);
1335 			rate_masks[i] = (u32) -1;
1336 			num_bands++;
1337 		}
1338 	}
1339 
1340 	if (req->flags & NL80211_SCAN_FLAG_MIN_PREQ_CONTENT)
1341 		flags |= IEEE80211_PROBE_FLAG_MIN_CONTENT;
1342 
1343 	ie = kcalloc(iebufsz, num_bands, GFP_KERNEL);
1344 	if (!ie) {
1345 		ret = -ENOMEM;
1346 		goto out;
1347 	}
1348 
1349 	ieee80211_prepare_scan_chandef(&chandef, req->scan_width);
1350 
1351 	ieee80211_build_preq_ies(sdata, ie, num_bands * iebufsz,
1352 				 &sched_scan_ies, req->ie,
1353 				 req->ie_len, bands_used, rate_masks, &chandef,
1354 				 flags);
1355 
1356 	ret = drv_sched_scan_start(local, sdata, req, &sched_scan_ies);
1357 	if (ret == 0) {
1358 		rcu_assign_pointer(local->sched_scan_sdata, sdata);
1359 		rcu_assign_pointer(local->sched_scan_req, req);
1360 	}
1361 
1362 	kfree(ie);
1363 
1364 out:
1365 	if (ret) {
1366 		/* Clean in case of failure after HW restart or upon resume. */
1367 		RCU_INIT_POINTER(local->sched_scan_sdata, NULL);
1368 		RCU_INIT_POINTER(local->sched_scan_req, NULL);
1369 	}
1370 
1371 	return ret;
1372 }
1373 
ieee80211_request_sched_scan_start(struct ieee80211_sub_if_data * sdata,struct cfg80211_sched_scan_request * req)1374 int ieee80211_request_sched_scan_start(struct ieee80211_sub_if_data *sdata,
1375 				       struct cfg80211_sched_scan_request *req)
1376 {
1377 	struct ieee80211_local *local = sdata->local;
1378 	int ret;
1379 
1380 	mutex_lock(&local->mtx);
1381 
1382 	if (rcu_access_pointer(local->sched_scan_sdata)) {
1383 		mutex_unlock(&local->mtx);
1384 		return -EBUSY;
1385 	}
1386 
1387 	ret = __ieee80211_request_sched_scan_start(sdata, req);
1388 
1389 	mutex_unlock(&local->mtx);
1390 	return ret;
1391 }
1392 
ieee80211_request_sched_scan_stop(struct ieee80211_local * local)1393 int ieee80211_request_sched_scan_stop(struct ieee80211_local *local)
1394 {
1395 	struct ieee80211_sub_if_data *sched_scan_sdata;
1396 	int ret = -ENOENT;
1397 
1398 	mutex_lock(&local->mtx);
1399 
1400 	if (!local->ops->sched_scan_stop) {
1401 		ret = -ENOTSUPP;
1402 		goto out;
1403 	}
1404 
1405 	/* We don't want to restart sched scan anymore. */
1406 	RCU_INIT_POINTER(local->sched_scan_req, NULL);
1407 
1408 	sched_scan_sdata = rcu_dereference_protected(local->sched_scan_sdata,
1409 						lockdep_is_held(&local->mtx));
1410 	if (sched_scan_sdata) {
1411 		ret = drv_sched_scan_stop(local, sched_scan_sdata);
1412 		if (!ret)
1413 			RCU_INIT_POINTER(local->sched_scan_sdata, NULL);
1414 	}
1415 out:
1416 	mutex_unlock(&local->mtx);
1417 
1418 	return ret;
1419 }
1420 
ieee80211_sched_scan_results(struct ieee80211_hw * hw)1421 void ieee80211_sched_scan_results(struct ieee80211_hw *hw)
1422 {
1423 	struct ieee80211_local *local = hw_to_local(hw);
1424 
1425 	trace_api_sched_scan_results(local);
1426 
1427 	cfg80211_sched_scan_results(hw->wiphy, 0);
1428 }
1429 EXPORT_SYMBOL(ieee80211_sched_scan_results);
1430 
ieee80211_sched_scan_end(struct ieee80211_local * local)1431 void ieee80211_sched_scan_end(struct ieee80211_local *local)
1432 {
1433 	mutex_lock(&local->mtx);
1434 
1435 	if (!rcu_access_pointer(local->sched_scan_sdata)) {
1436 		mutex_unlock(&local->mtx);
1437 		return;
1438 	}
1439 
1440 	RCU_INIT_POINTER(local->sched_scan_sdata, NULL);
1441 
1442 	/* If sched scan was aborted by the driver. */
1443 	RCU_INIT_POINTER(local->sched_scan_req, NULL);
1444 
1445 	mutex_unlock(&local->mtx);
1446 
1447 	cfg80211_sched_scan_stopped(local->hw.wiphy, 0);
1448 }
1449 
ieee80211_sched_scan_stopped_work(struct work_struct * work)1450 void ieee80211_sched_scan_stopped_work(struct work_struct *work)
1451 {
1452 	struct ieee80211_local *local =
1453 		container_of(work, struct ieee80211_local,
1454 			     sched_scan_stopped_work);
1455 
1456 	ieee80211_sched_scan_end(local);
1457 }
1458 
ieee80211_sched_scan_stopped(struct ieee80211_hw * hw)1459 void ieee80211_sched_scan_stopped(struct ieee80211_hw *hw)
1460 {
1461 	struct ieee80211_local *local = hw_to_local(hw);
1462 
1463 	trace_api_sched_scan_stopped(local);
1464 
1465 	/*
1466 	 * this shouldn't really happen, so for simplicity
1467 	 * simply ignore it, and let mac80211 reconfigure
1468 	 * the sched scan later on.
1469 	 */
1470 	if (local->in_reconfig)
1471 		return;
1472 
1473 	schedule_work(&local->sched_scan_stopped_work);
1474 }
1475 EXPORT_SYMBOL(ieee80211_sched_scan_stopped);
1476