xref: /openbmc/linux/net/wireless/chan.c (revision bb66fc67)
1 /*
2  * This file contains helper code to handle channel
3  * settings and keeping track of what is possible at
4  * any point in time.
5  *
6  * Copyright 2009	Johannes Berg <johannes@sipsolutions.net>
7  */
8 
9 #include <linux/export.h>
10 #include <net/cfg80211.h>
11 #include "core.h"
12 #include "rdev-ops.h"
13 
14 void cfg80211_chandef_create(struct cfg80211_chan_def *chandef,
15 			     struct ieee80211_channel *chan,
16 			     enum nl80211_channel_type chan_type)
17 {
18 	if (WARN_ON(!chan))
19 		return;
20 
21 	chandef->chan = chan;
22 	chandef->center_freq2 = 0;
23 
24 	switch (chan_type) {
25 	case NL80211_CHAN_NO_HT:
26 		chandef->width = NL80211_CHAN_WIDTH_20_NOHT;
27 		chandef->center_freq1 = chan->center_freq;
28 		break;
29 	case NL80211_CHAN_HT20:
30 		chandef->width = NL80211_CHAN_WIDTH_20;
31 		chandef->center_freq1 = chan->center_freq;
32 		break;
33 	case NL80211_CHAN_HT40PLUS:
34 		chandef->width = NL80211_CHAN_WIDTH_40;
35 		chandef->center_freq1 = chan->center_freq + 10;
36 		break;
37 	case NL80211_CHAN_HT40MINUS:
38 		chandef->width = NL80211_CHAN_WIDTH_40;
39 		chandef->center_freq1 = chan->center_freq - 10;
40 		break;
41 	default:
42 		WARN_ON(1);
43 	}
44 }
45 EXPORT_SYMBOL(cfg80211_chandef_create);
46 
47 bool cfg80211_chandef_valid(const struct cfg80211_chan_def *chandef)
48 {
49 	u32 control_freq;
50 
51 	if (!chandef->chan)
52 		return false;
53 
54 	control_freq = chandef->chan->center_freq;
55 
56 	switch (chandef->width) {
57 	case NL80211_CHAN_WIDTH_5:
58 	case NL80211_CHAN_WIDTH_10:
59 	case NL80211_CHAN_WIDTH_20:
60 	case NL80211_CHAN_WIDTH_20_NOHT:
61 		if (chandef->center_freq1 != control_freq)
62 			return false;
63 		if (chandef->center_freq2)
64 			return false;
65 		break;
66 	case NL80211_CHAN_WIDTH_40:
67 		if (chandef->center_freq1 != control_freq + 10 &&
68 		    chandef->center_freq1 != control_freq - 10)
69 			return false;
70 		if (chandef->center_freq2)
71 			return false;
72 		break;
73 	case NL80211_CHAN_WIDTH_80P80:
74 		if (chandef->center_freq1 != control_freq + 30 &&
75 		    chandef->center_freq1 != control_freq + 10 &&
76 		    chandef->center_freq1 != control_freq - 10 &&
77 		    chandef->center_freq1 != control_freq - 30)
78 			return false;
79 		if (!chandef->center_freq2)
80 			return false;
81 		/* adjacent is not allowed -- that's a 160 MHz channel */
82 		if (chandef->center_freq1 - chandef->center_freq2 == 80 ||
83 		    chandef->center_freq2 - chandef->center_freq1 == 80)
84 			return false;
85 		break;
86 	case NL80211_CHAN_WIDTH_80:
87 		if (chandef->center_freq1 != control_freq + 30 &&
88 		    chandef->center_freq1 != control_freq + 10 &&
89 		    chandef->center_freq1 != control_freq - 10 &&
90 		    chandef->center_freq1 != control_freq - 30)
91 			return false;
92 		if (chandef->center_freq2)
93 			return false;
94 		break;
95 	case NL80211_CHAN_WIDTH_160:
96 		if (chandef->center_freq1 != control_freq + 70 &&
97 		    chandef->center_freq1 != control_freq + 50 &&
98 		    chandef->center_freq1 != control_freq + 30 &&
99 		    chandef->center_freq1 != control_freq + 10 &&
100 		    chandef->center_freq1 != control_freq - 10 &&
101 		    chandef->center_freq1 != control_freq - 30 &&
102 		    chandef->center_freq1 != control_freq - 50 &&
103 		    chandef->center_freq1 != control_freq - 70)
104 			return false;
105 		if (chandef->center_freq2)
106 			return false;
107 		break;
108 	default:
109 		return false;
110 	}
111 
112 	return true;
113 }
114 EXPORT_SYMBOL(cfg80211_chandef_valid);
115 
116 static void chandef_primary_freqs(const struct cfg80211_chan_def *c,
117 				  int *pri40, int *pri80)
118 {
119 	int tmp;
120 
121 	switch (c->width) {
122 	case NL80211_CHAN_WIDTH_40:
123 		*pri40 = c->center_freq1;
124 		*pri80 = 0;
125 		break;
126 	case NL80211_CHAN_WIDTH_80:
127 	case NL80211_CHAN_WIDTH_80P80:
128 		*pri80 = c->center_freq1;
129 		/* n_P20 */
130 		tmp = (30 + c->chan->center_freq - c->center_freq1)/20;
131 		/* n_P40 */
132 		tmp /= 2;
133 		/* freq_P40 */
134 		*pri40 = c->center_freq1 - 20 + 40 * tmp;
135 		break;
136 	case NL80211_CHAN_WIDTH_160:
137 		/* n_P20 */
138 		tmp = (70 + c->chan->center_freq - c->center_freq1)/20;
139 		/* n_P40 */
140 		tmp /= 2;
141 		/* freq_P40 */
142 		*pri40 = c->center_freq1 - 60 + 40 * tmp;
143 		/* n_P80 */
144 		tmp /= 2;
145 		*pri80 = c->center_freq1 - 40 + 80 * tmp;
146 		break;
147 	default:
148 		WARN_ON_ONCE(1);
149 	}
150 }
151 
152 static int cfg80211_chandef_get_width(const struct cfg80211_chan_def *c)
153 {
154 	int width;
155 
156 	switch (c->width) {
157 	case NL80211_CHAN_WIDTH_5:
158 		width = 5;
159 		break;
160 	case NL80211_CHAN_WIDTH_10:
161 		width = 10;
162 		break;
163 	case NL80211_CHAN_WIDTH_20:
164 	case NL80211_CHAN_WIDTH_20_NOHT:
165 		width = 20;
166 		break;
167 	case NL80211_CHAN_WIDTH_40:
168 		width = 40;
169 		break;
170 	case NL80211_CHAN_WIDTH_80P80:
171 	case NL80211_CHAN_WIDTH_80:
172 		width = 80;
173 		break;
174 	case NL80211_CHAN_WIDTH_160:
175 		width = 160;
176 		break;
177 	default:
178 		WARN_ON_ONCE(1);
179 		return -1;
180 	}
181 	return width;
182 }
183 
184 const struct cfg80211_chan_def *
185 cfg80211_chandef_compatible(const struct cfg80211_chan_def *c1,
186 			    const struct cfg80211_chan_def *c2)
187 {
188 	u32 c1_pri40, c1_pri80, c2_pri40, c2_pri80;
189 
190 	/* If they are identical, return */
191 	if (cfg80211_chandef_identical(c1, c2))
192 		return c1;
193 
194 	/* otherwise, must have same control channel */
195 	if (c1->chan != c2->chan)
196 		return NULL;
197 
198 	/*
199 	 * If they have the same width, but aren't identical,
200 	 * then they can't be compatible.
201 	 */
202 	if (c1->width == c2->width)
203 		return NULL;
204 
205 	/*
206 	 * can't be compatible if one of them is 5 or 10 MHz,
207 	 * but they don't have the same width.
208 	 */
209 	if (c1->width == NL80211_CHAN_WIDTH_5 ||
210 	    c1->width == NL80211_CHAN_WIDTH_10 ||
211 	    c2->width == NL80211_CHAN_WIDTH_5 ||
212 	    c2->width == NL80211_CHAN_WIDTH_10)
213 		return NULL;
214 
215 	if (c1->width == NL80211_CHAN_WIDTH_20_NOHT ||
216 	    c1->width == NL80211_CHAN_WIDTH_20)
217 		return c2;
218 
219 	if (c2->width == NL80211_CHAN_WIDTH_20_NOHT ||
220 	    c2->width == NL80211_CHAN_WIDTH_20)
221 		return c1;
222 
223 	chandef_primary_freqs(c1, &c1_pri40, &c1_pri80);
224 	chandef_primary_freqs(c2, &c2_pri40, &c2_pri80);
225 
226 	if (c1_pri40 != c2_pri40)
227 		return NULL;
228 
229 	WARN_ON(!c1_pri80 && !c2_pri80);
230 	if (c1_pri80 && c2_pri80 && c1_pri80 != c2_pri80)
231 		return NULL;
232 
233 	if (c1->width > c2->width)
234 		return c1;
235 	return c2;
236 }
237 EXPORT_SYMBOL(cfg80211_chandef_compatible);
238 
239 static void cfg80211_set_chans_dfs_state(struct wiphy *wiphy, u32 center_freq,
240 					 u32 bandwidth,
241 					 enum nl80211_dfs_state dfs_state)
242 {
243 	struct ieee80211_channel *c;
244 	u32 freq;
245 
246 	for (freq = center_freq - bandwidth/2 + 10;
247 	     freq <= center_freq + bandwidth/2 - 10;
248 	     freq += 20) {
249 		c = ieee80211_get_channel(wiphy, freq);
250 		if (!c || !(c->flags & IEEE80211_CHAN_RADAR))
251 			continue;
252 
253 		c->dfs_state = dfs_state;
254 		c->dfs_state_entered = jiffies;
255 	}
256 }
257 
258 void cfg80211_set_dfs_state(struct wiphy *wiphy,
259 			    const struct cfg80211_chan_def *chandef,
260 			    enum nl80211_dfs_state dfs_state)
261 {
262 	int width;
263 
264 	if (WARN_ON(!cfg80211_chandef_valid(chandef)))
265 		return;
266 
267 	width = cfg80211_chandef_get_width(chandef);
268 	if (width < 0)
269 		return;
270 
271 	cfg80211_set_chans_dfs_state(wiphy, chandef->center_freq1,
272 				     width, dfs_state);
273 
274 	if (!chandef->center_freq2)
275 		return;
276 	cfg80211_set_chans_dfs_state(wiphy, chandef->center_freq2,
277 				     width, dfs_state);
278 }
279 
280 static u32 cfg80211_get_start_freq(u32 center_freq,
281 				   u32 bandwidth)
282 {
283 	u32 start_freq;
284 
285 	if (bandwidth <= 20)
286 		start_freq = center_freq;
287 	else
288 		start_freq = center_freq - bandwidth/2 + 10;
289 
290 	return start_freq;
291 }
292 
293 static u32 cfg80211_get_end_freq(u32 center_freq,
294 				 u32 bandwidth)
295 {
296 	u32 end_freq;
297 
298 	if (bandwidth <= 20)
299 		end_freq = center_freq;
300 	else
301 		end_freq = center_freq + bandwidth/2 - 10;
302 
303 	return end_freq;
304 }
305 
306 static int cfg80211_get_chans_dfs_required(struct wiphy *wiphy,
307 					    u32 center_freq,
308 					    u32 bandwidth)
309 {
310 	struct ieee80211_channel *c;
311 	u32 freq, start_freq, end_freq;
312 
313 	start_freq = cfg80211_get_start_freq(center_freq, bandwidth);
314 	end_freq = cfg80211_get_end_freq(center_freq, bandwidth);
315 
316 	for (freq = start_freq; freq <= end_freq; freq += 20) {
317 		c = ieee80211_get_channel(wiphy, freq);
318 		if (!c)
319 			return -EINVAL;
320 
321 		if (c->flags & IEEE80211_CHAN_RADAR)
322 			return 1;
323 	}
324 	return 0;
325 }
326 
327 
328 int cfg80211_chandef_dfs_required(struct wiphy *wiphy,
329 				  const struct cfg80211_chan_def *chandef)
330 {
331 	int width;
332 	int r;
333 
334 	if (WARN_ON(!cfg80211_chandef_valid(chandef)))
335 		return -EINVAL;
336 
337 	width = cfg80211_chandef_get_width(chandef);
338 	if (width < 0)
339 		return -EINVAL;
340 
341 	r = cfg80211_get_chans_dfs_required(wiphy, chandef->center_freq1,
342 					    width);
343 	if (r)
344 		return r;
345 
346 	if (!chandef->center_freq2)
347 		return 0;
348 
349 	return cfg80211_get_chans_dfs_required(wiphy, chandef->center_freq2,
350 					       width);
351 }
352 EXPORT_SYMBOL(cfg80211_chandef_dfs_required);
353 
354 static int cfg80211_get_chans_dfs_usable(struct wiphy *wiphy,
355 					 u32 center_freq,
356 					 u32 bandwidth)
357 {
358 	struct ieee80211_channel *c;
359 	u32 freq, start_freq, end_freq;
360 	int count = 0;
361 
362 	start_freq = cfg80211_get_start_freq(center_freq, bandwidth);
363 	end_freq = cfg80211_get_end_freq(center_freq, bandwidth);
364 
365 	/*
366 	 * Check entire range of channels for the bandwidth.
367 	 * Check all channels are DFS channels (DFS_USABLE or
368 	 * DFS_AVAILABLE). Return number of usable channels
369 	 * (require CAC). Allow DFS and non-DFS channel mix.
370 	 */
371 	for (freq = start_freq; freq <= end_freq; freq += 20) {
372 		c = ieee80211_get_channel(wiphy, freq);
373 		if (!c)
374 			return -EINVAL;
375 
376 		if (c->flags & IEEE80211_CHAN_DISABLED)
377 			return -EINVAL;
378 
379 		if (c->flags & IEEE80211_CHAN_RADAR) {
380 			if (c->dfs_state == NL80211_DFS_UNAVAILABLE)
381 				return -EINVAL;
382 
383 			if (c->dfs_state == NL80211_DFS_USABLE)
384 				count++;
385 		}
386 	}
387 
388 	return count;
389 }
390 
391 bool cfg80211_chandef_dfs_usable(struct wiphy *wiphy,
392 				 const struct cfg80211_chan_def *chandef)
393 {
394 	int width;
395 	int r1, r2 = 0;
396 
397 	if (WARN_ON(!cfg80211_chandef_valid(chandef)))
398 		return false;
399 
400 	width = cfg80211_chandef_get_width(chandef);
401 	if (width < 0)
402 		return false;
403 
404 	r1 = cfg80211_get_chans_dfs_usable(wiphy, chandef->center_freq1,
405 					  width);
406 
407 	if (r1 < 0)
408 		return false;
409 
410 	switch (chandef->width) {
411 	case NL80211_CHAN_WIDTH_80P80:
412 		WARN_ON(!chandef->center_freq2);
413 		r2 = cfg80211_get_chans_dfs_usable(wiphy,
414 						   chandef->center_freq2,
415 						   width);
416 		if (r2 < 0)
417 			return false;
418 		break;
419 	default:
420 		WARN_ON(chandef->center_freq2);
421 		break;
422 	}
423 
424 	return (r1 + r2 > 0);
425 }
426 
427 
428 static bool cfg80211_get_chans_dfs_available(struct wiphy *wiphy,
429 					     u32 center_freq,
430 					     u32 bandwidth)
431 {
432 	struct ieee80211_channel *c;
433 	u32 freq, start_freq, end_freq;
434 
435 	start_freq = cfg80211_get_start_freq(center_freq, bandwidth);
436 	end_freq = cfg80211_get_end_freq(center_freq, bandwidth);
437 
438 	/*
439 	 * Check entire range of channels for the bandwidth.
440 	 * If any channel in between is disabled or has not
441 	 * had gone through CAC return false
442 	 */
443 	for (freq = start_freq; freq <= end_freq; freq += 20) {
444 		c = ieee80211_get_channel(wiphy, freq);
445 		if (!c)
446 			return false;
447 
448 		if (c->flags & IEEE80211_CHAN_DISABLED)
449 			return false;
450 
451 		if ((c->flags & IEEE80211_CHAN_RADAR)  &&
452 		    (c->dfs_state != NL80211_DFS_AVAILABLE))
453 			return false;
454 	}
455 
456 	return true;
457 }
458 
459 static bool cfg80211_chandef_dfs_available(struct wiphy *wiphy,
460 				const struct cfg80211_chan_def *chandef)
461 {
462 	int width;
463 	int r;
464 
465 	if (WARN_ON(!cfg80211_chandef_valid(chandef)))
466 		return false;
467 
468 	width = cfg80211_chandef_get_width(chandef);
469 	if (width < 0)
470 		return false;
471 
472 	r = cfg80211_get_chans_dfs_available(wiphy, chandef->center_freq1,
473 					     width);
474 
475 	/* If any of channels unavailable for cf1 just return */
476 	if (!r)
477 		return r;
478 
479 	switch (chandef->width) {
480 	case NL80211_CHAN_WIDTH_80P80:
481 		WARN_ON(!chandef->center_freq2);
482 		r = cfg80211_get_chans_dfs_available(wiphy,
483 						     chandef->center_freq2,
484 						     width);
485 	default:
486 		WARN_ON(chandef->center_freq2);
487 		break;
488 	}
489 
490 	return r;
491 }
492 
493 static unsigned int cfg80211_get_chans_dfs_cac_time(struct wiphy *wiphy,
494 						    u32 center_freq,
495 						    u32 bandwidth)
496 {
497 	struct ieee80211_channel *c;
498 	u32 start_freq, end_freq, freq;
499 	unsigned int dfs_cac_ms = 0;
500 
501 	start_freq = cfg80211_get_start_freq(center_freq, bandwidth);
502 	end_freq = cfg80211_get_end_freq(center_freq, bandwidth);
503 
504 	for (freq = start_freq; freq <= end_freq; freq += 20) {
505 		c = ieee80211_get_channel(wiphy, freq);
506 		if (!c)
507 			return 0;
508 
509 		if (c->flags & IEEE80211_CHAN_DISABLED)
510 			return 0;
511 
512 		if (!(c->flags & IEEE80211_CHAN_RADAR))
513 			continue;
514 
515 		if (c->dfs_cac_ms > dfs_cac_ms)
516 			dfs_cac_ms = c->dfs_cac_ms;
517 	}
518 
519 	return dfs_cac_ms;
520 }
521 
522 unsigned int
523 cfg80211_chandef_dfs_cac_time(struct wiphy *wiphy,
524 			      const struct cfg80211_chan_def *chandef)
525 {
526 	int width;
527 	unsigned int t1 = 0, t2 = 0;
528 
529 	if (WARN_ON(!cfg80211_chandef_valid(chandef)))
530 		return 0;
531 
532 	width = cfg80211_chandef_get_width(chandef);
533 	if (width < 0)
534 		return 0;
535 
536 	t1 = cfg80211_get_chans_dfs_cac_time(wiphy,
537 					     chandef->center_freq1,
538 					     width);
539 
540 	if (!chandef->center_freq2)
541 		return t1;
542 
543 	t2 = cfg80211_get_chans_dfs_cac_time(wiphy,
544 					     chandef->center_freq2,
545 					     width);
546 
547 	return max(t1, t2);
548 }
549 
550 static bool cfg80211_secondary_chans_ok(struct wiphy *wiphy,
551 					u32 center_freq, u32 bandwidth,
552 					u32 prohibited_flags)
553 {
554 	struct ieee80211_channel *c;
555 	u32 freq, start_freq, end_freq;
556 
557 	start_freq = cfg80211_get_start_freq(center_freq, bandwidth);
558 	end_freq = cfg80211_get_end_freq(center_freq, bandwidth);
559 
560 	for (freq = start_freq; freq <= end_freq; freq += 20) {
561 		c = ieee80211_get_channel(wiphy, freq);
562 		if (!c || c->flags & prohibited_flags)
563 			return false;
564 	}
565 
566 	return true;
567 }
568 
569 bool cfg80211_chandef_usable(struct wiphy *wiphy,
570 			     const struct cfg80211_chan_def *chandef,
571 			     u32 prohibited_flags)
572 {
573 	struct ieee80211_sta_ht_cap *ht_cap;
574 	struct ieee80211_sta_vht_cap *vht_cap;
575 	u32 width, control_freq;
576 
577 	if (WARN_ON(!cfg80211_chandef_valid(chandef)))
578 		return false;
579 
580 	ht_cap = &wiphy->bands[chandef->chan->band]->ht_cap;
581 	vht_cap = &wiphy->bands[chandef->chan->band]->vht_cap;
582 
583 	control_freq = chandef->chan->center_freq;
584 
585 	switch (chandef->width) {
586 	case NL80211_CHAN_WIDTH_5:
587 		width = 5;
588 		break;
589 	case NL80211_CHAN_WIDTH_10:
590 		width = 10;
591 		break;
592 	case NL80211_CHAN_WIDTH_20:
593 		if (!ht_cap->ht_supported)
594 			return false;
595 	case NL80211_CHAN_WIDTH_20_NOHT:
596 		width = 20;
597 		break;
598 	case NL80211_CHAN_WIDTH_40:
599 		width = 40;
600 		if (!ht_cap->ht_supported)
601 			return false;
602 		if (!(ht_cap->cap & IEEE80211_HT_CAP_SUP_WIDTH_20_40) ||
603 		    ht_cap->cap & IEEE80211_HT_CAP_40MHZ_INTOLERANT)
604 			return false;
605 		if (chandef->center_freq1 < control_freq &&
606 		    chandef->chan->flags & IEEE80211_CHAN_NO_HT40MINUS)
607 			return false;
608 		if (chandef->center_freq1 > control_freq &&
609 		    chandef->chan->flags & IEEE80211_CHAN_NO_HT40PLUS)
610 			return false;
611 		break;
612 	case NL80211_CHAN_WIDTH_80P80:
613 		if (!(vht_cap->cap & IEEE80211_VHT_CAP_SUPP_CHAN_WIDTH_160_80PLUS80MHZ))
614 			return false;
615 	case NL80211_CHAN_WIDTH_80:
616 		if (!vht_cap->vht_supported)
617 			return false;
618 		prohibited_flags |= IEEE80211_CHAN_NO_80MHZ;
619 		width = 80;
620 		break;
621 	case NL80211_CHAN_WIDTH_160:
622 		if (!vht_cap->vht_supported)
623 			return false;
624 		if (!(vht_cap->cap & IEEE80211_VHT_CAP_SUPP_CHAN_WIDTH_160MHZ))
625 			return false;
626 		prohibited_flags |= IEEE80211_CHAN_NO_160MHZ;
627 		width = 160;
628 		break;
629 	default:
630 		WARN_ON_ONCE(1);
631 		return false;
632 	}
633 
634 	/*
635 	 * TODO: What if there are only certain 80/160/80+80 MHz channels
636 	 *	 allowed by the driver, or only certain combinations?
637 	 *	 For 40 MHz the driver can set the NO_HT40 flags, but for
638 	 *	 80/160 MHz and in particular 80+80 MHz this isn't really
639 	 *	 feasible and we only have NO_80MHZ/NO_160MHZ so far but
640 	 *	 no way to cover 80+80 MHz or more complex restrictions.
641 	 *	 Note that such restrictions also need to be advertised to
642 	 *	 userspace, for example for P2P channel selection.
643 	 */
644 
645 	if (width > 20)
646 		prohibited_flags |= IEEE80211_CHAN_NO_OFDM;
647 
648 	/* 5 and 10 MHz are only defined for the OFDM PHY */
649 	if (width < 20)
650 		prohibited_flags |= IEEE80211_CHAN_NO_OFDM;
651 
652 
653 	if (!cfg80211_secondary_chans_ok(wiphy, chandef->center_freq1,
654 					 width, prohibited_flags))
655 		return false;
656 
657 	if (!chandef->center_freq2)
658 		return true;
659 	return cfg80211_secondary_chans_ok(wiphy, chandef->center_freq2,
660 					   width, prohibited_flags);
661 }
662 EXPORT_SYMBOL(cfg80211_chandef_usable);
663 
664 bool cfg80211_reg_can_beacon(struct wiphy *wiphy,
665 			     struct cfg80211_chan_def *chandef)
666 {
667 	bool res;
668 	u32 prohibited_flags = IEEE80211_CHAN_DISABLED |
669 			       IEEE80211_CHAN_NO_IR |
670 			       IEEE80211_CHAN_RADAR;
671 
672 	trace_cfg80211_reg_can_beacon(wiphy, chandef);
673 
674 	if (cfg80211_chandef_dfs_required(wiphy, chandef) > 0 &&
675 	    cfg80211_chandef_dfs_available(wiphy, chandef)) {
676 		/* We can skip IEEE80211_CHAN_NO_IR if chandef dfs available */
677 		prohibited_flags = IEEE80211_CHAN_DISABLED;
678 	}
679 
680 	res = cfg80211_chandef_usable(wiphy, chandef, prohibited_flags);
681 
682 	trace_cfg80211_return_bool(res);
683 	return res;
684 }
685 EXPORT_SYMBOL(cfg80211_reg_can_beacon);
686 
687 int cfg80211_set_monitor_channel(struct cfg80211_registered_device *rdev,
688 				 struct cfg80211_chan_def *chandef)
689 {
690 	if (!rdev->ops->set_monitor_channel)
691 		return -EOPNOTSUPP;
692 	if (!cfg80211_has_monitors_only(rdev))
693 		return -EBUSY;
694 
695 	return rdev_set_monitor_channel(rdev, chandef);
696 }
697 
698 void
699 cfg80211_get_chan_state(struct wireless_dev *wdev,
700 		        struct ieee80211_channel **chan,
701 		        enum cfg80211_chan_mode *chanmode,
702 		        u8 *radar_detect)
703 {
704 	*chan = NULL;
705 	*chanmode = CHAN_MODE_UNDEFINED;
706 
707 	ASSERT_WDEV_LOCK(wdev);
708 
709 	if (wdev->netdev && !netif_running(wdev->netdev))
710 		return;
711 
712 	switch (wdev->iftype) {
713 	case NL80211_IFTYPE_ADHOC:
714 		if (wdev->current_bss) {
715 			*chan = wdev->current_bss->pub.channel;
716 			*chanmode = (wdev->ibss_fixed &&
717 				     !wdev->ibss_dfs_possible)
718 				  ? CHAN_MODE_SHARED
719 				  : CHAN_MODE_EXCLUSIVE;
720 
721 			/* consider worst-case - IBSS can try to return to the
722 			 * original user-specified channel as creator */
723 			if (wdev->ibss_dfs_possible)
724 				*radar_detect |= BIT(wdev->chandef.width);
725 			return;
726 		}
727 		break;
728 	case NL80211_IFTYPE_STATION:
729 	case NL80211_IFTYPE_P2P_CLIENT:
730 		if (wdev->current_bss) {
731 			*chan = wdev->current_bss->pub.channel;
732 			*chanmode = CHAN_MODE_SHARED;
733 			return;
734 		}
735 		break;
736 	case NL80211_IFTYPE_AP:
737 	case NL80211_IFTYPE_P2P_GO:
738 		if (wdev->cac_started) {
739 			*chan = wdev->chandef.chan;
740 			*chanmode = CHAN_MODE_SHARED;
741 			*radar_detect |= BIT(wdev->chandef.width);
742 		} else if (wdev->beacon_interval) {
743 			*chan = wdev->chandef.chan;
744 			*chanmode = CHAN_MODE_SHARED;
745 
746 			if (cfg80211_chandef_dfs_required(wdev->wiphy,
747 							  &wdev->chandef))
748 				*radar_detect |= BIT(wdev->chandef.width);
749 		}
750 		return;
751 	case NL80211_IFTYPE_MESH_POINT:
752 		if (wdev->mesh_id_len) {
753 			*chan = wdev->chandef.chan;
754 			*chanmode = CHAN_MODE_SHARED;
755 
756 			if (cfg80211_chandef_dfs_required(wdev->wiphy,
757 							  &wdev->chandef))
758 				*radar_detect |= BIT(wdev->chandef.width);
759 		}
760 		return;
761 	case NL80211_IFTYPE_MONITOR:
762 	case NL80211_IFTYPE_AP_VLAN:
763 	case NL80211_IFTYPE_WDS:
764 	case NL80211_IFTYPE_P2P_DEVICE:
765 		/* these interface types don't really have a channel */
766 		return;
767 	case NL80211_IFTYPE_UNSPECIFIED:
768 	case NUM_NL80211_IFTYPES:
769 		WARN_ON(1);
770 	}
771 }
772