aboutsummaryrefslogtreecommitdiff
path: root/net/wireless/reg.c
blob: 290ececd4f1189888a2280d43ab68a8b751d4824 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
886
887
888
889
890
891
892
893
894
895
896
897
898
899
900
901
902
903
904
905
906
907
908
909
910
911
912
913
914
915
916
917
918
919
920
921
922
923
924
/*
 * Copyright 2002-2005, Instant802 Networks, Inc.
 * Copyright 2005-2006, Devicescape Software, Inc.
 * Copyright 2007	Johannes Berg <johannes@sipsolutions.net>
 * Copyright 2008	Luis R. Rodriguez <lrodriguz@atheros.com>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation.
 */

/**
 * DOC: Wireless regulatory infrastructure
 *
 * The usual implementation is for a driver to read a device EEPROM to
 * determine which regulatory domain it should be operating under, then
 * looking up the allowable channels in a driver-local table and finally
 * registering those channels in the wiphy structure.
 *
 * Another set of compliance enforcement is for drivers to use their
 * own compliance limits which can be stored on the EEPROM. The host
 * driver or firmware may ensure these are used.
 *
 * In addition to all this we provide an extra layer of regulatory
 * conformance. For drivers which do not have any regulatory
 * information CRDA provides the complete regulatory solution.
 * For others it provides a community effort on further restrictions
 * to enhance compliance.
 *
 * Note: When number of rules --> infinity we will not be able to
 * index on alpha2 any more, instead we'll probably have to
 * rely on some SHA1 checksum of the regdomain for example.
 *
 */
#include <linux/kernel.h>
#include <linux/list.h>
#include <linux/random.h>
#include <linux/nl80211.h>
#include <linux/platform_device.h>
#include <net/wireless.h>
#include <net/cfg80211.h>
#include "core.h"
#include "reg.h"

/**
 * struct regulatory_request - receipt of last regulatory request
 *
 * @wiphy: this is set if this request's initiator is
 * 	%REGDOM_SET_BY_COUNTRY_IE or %REGDOM_SET_BY_DRIVER. This
 * 	can be used by the wireless core to deal with conflicts
 * 	and potentially inform users of which devices specifically
 * 	cased the conflicts.
 * @initiator: indicates who sent this request, could be any of
 * 	of those set in reg_set_by, %REGDOM_SET_BY_*
 * @alpha2: the ISO / IEC 3166 alpha2 country code of the requested
 * 	regulatory domain. We have a few special codes:
 * 	00 - World regulatory domain
 * 	99 - built by driver but a specific alpha2 cannot be determined
 * 	98 - result of an intersection between two regulatory domains
 * @intersect: indicates whether the wireless core should intersect
 * 	the requested regulatory domain with the presently set regulatory
 * 	domain.
 */
struct regulatory_request {
	struct wiphy *wiphy;
	enum reg_set_by initiator;
	char alpha2[2];
	bool intersect;
};

/* Receipt of information from last regulatory request */
static struct regulatory_request *last_request;

/* To trigger userspace events */
static struct platform_device *reg_pdev;

/* Keep the ordering from large to small */
static u32 supported_bandwidths[] = {
	MHZ_TO_KHZ(40),
	MHZ_TO_KHZ(20),
};

/* Central wireless core regulatory domains, we only need two,
 * the current one and a world regulatory domain in case we have no
 * information to give us an alpha2 */
static const struct ieee80211_regdomain *cfg80211_regdomain;

/* We keep a static world regulatory domain in case of the absence of CRDA */
static const struct ieee80211_regdomain world_regdom = {
	.n_reg_rules = 1,
	.alpha2 =  "00",
	.reg_rules = {
		REG_RULE(2412-10, 2462+10, 40, 6, 20,
			NL80211_RRF_PASSIVE_SCAN |
			NL80211_RRF_NO_IBSS),
	}
};

static const struct ieee80211_regdomain *cfg80211_world_regdom =
	&world_regdom;

#ifdef CONFIG_WIRELESS_OLD_REGULATORY
static char *ieee80211_regdom = "US";
module_param(ieee80211_regdom, charp, 0444);
MODULE_PARM_DESC(ieee80211_regdom, "IEEE 802.11 regulatory domain code");

/* We assume 40 MHz bandwidth for the old regulatory work.
 * We make emphasis we are using the exact same frequencies
 * as before */

static const struct ieee80211_regdomain us_regdom = {
	.n_reg_rules = 6,
	.alpha2 =  "US",
	.reg_rules = {
		/* IEEE 802.11b/g, channels 1..11 */
		REG_RULE(2412-10, 2462+10, 40, 6, 27, 0),
		/* IEEE 802.11a, channel 36 */
		REG_RULE(5180-10, 5180+10, 40, 6, 23, 0),
		/* IEEE 802.11a, channel 40 */
		REG_RULE(5200-10, 5200+10, 40, 6, 23, 0),
		/* IEEE 802.11a, channel 44 */
		REG_RULE(5220-10, 5220+10, 40, 6, 23, 0),
		/* IEEE 802.11a, channels 48..64 */
		REG_RULE(5240-10, 5320+10, 40, 6, 23, 0),
		/* IEEE 802.11a, channels 149..165, outdoor */
		REG_RULE(5745-10, 5825+10, 40, 6, 30, 0),
	}
};

static const struct ieee80211_regdomain jp_regdom = {
	.n_reg_rules = 3,
	.alpha2 =  "JP",
	.reg_rules = {
		/* IEEE 802.11b/g, channels 1..14 */
		REG_RULE(2412-10, 2484+10, 40, 6, 20, 0),
		/* IEEE 802.11a, channels 34..48 */
		REG_RULE(5170-10, 5240+10, 40, 6, 20,
			NL80211_RRF_PASSIVE_SCAN),
		/* IEEE 802.11a, channels 52..64 */
		REG_RULE(5260-10, 5320+10, 40, 6, 20,
			NL80211_RRF_NO_IBSS |
			NL80211_RRF_DFS),
	}
};

static const struct ieee80211_regdomain eu_regdom = {
	.n_reg_rules = 6,
	/* This alpha2 is bogus, we leave it here just for stupid
	 * backward compatibility */
	.alpha2 =  "EU",
	.reg_rules = {
		/* IEEE 802.11b/g, channels 1..13 */
		REG_RULE(2412-10, 2472+10, 40, 6, 20, 0),
		/* IEEE 802.11a, channel 36 */
		REG_RULE(5180-10, 5180+10, 40, 6, 23,
			NL80211_RRF_PASSIVE_SCAN),
		/* IEEE 802.11a, channel 40 */
		REG_RULE(5200-10, 5200+10, 40, 6, 23,
			NL80211_RRF_PASSIVE_SCAN),
		/* IEEE 802.11a, channel 44 */
		REG_RULE(5220-10, 5220+10, 40, 6, 23,
			NL80211_RRF_PASSIVE_SCAN),
		/* IEEE 802.11a, channels 48..64 */
		REG_RULE(5240-10, 5320+10, 40, 6, 20,
			NL80211_RRF_NO_IBSS |
			NL80211_RRF_DFS),
		/* IEEE 802.11a, channels 100..140 */
		REG_RULE(5500-10, 5700+10, 40, 6, 30,
			NL80211_RRF_NO_IBSS |
			NL80211_RRF_DFS),
	}
};

static const struct ieee80211_regdomain *static_regdom(char *alpha2)
{
	if (alpha2[0] == 'U' && alpha2[1] == 'S')
		return &us_regdom;
	if (alpha2[0] == 'J' && alpha2[1] == 'P')
		return &jp_regdom;
	if (alpha2[0] == 'E' && alpha2[1] == 'U')
		return &eu_regdom;
	/* Default, as per the old rules */
	return &us_regdom;
}

static bool is_old_static_regdom(const struct ieee80211_regdomain *rd)
{
	if (rd == &us_regdom || rd == &jp_regdom || rd == &eu_regdom)
		return true;
	return false;
}
#else
static inline bool is_old_static_regdom(const struct ieee80211_regdomain *rd)
{
	return false;
}
#endif

static void reset_regdomains(void)
{
	/* avoid freeing static information or freeing something twice */
	if (cfg80211_regdomain == cfg80211_world_regdom)
		cfg80211_regdomain = NULL;
	if (cfg80211_world_regdom == &world_regdom)
		cfg80211_world_regdom = NULL;
	if (cfg80211_regdomain == &world_regdom)
		cfg80211_regdomain = NULL;
	if (is_old_static_regdom(cfg80211_regdomain))
		cfg80211_regdomain = NULL;

	kfree(cfg80211_regdomain);
	kfree(cfg80211_world_regdom);

	cfg80211_world_regdom = &world_regdom;
	cfg80211_regdomain = NULL;
}

/* Dynamic world regulatory domain requested by the wireless
 * core upon initialization */
static void update_world_regdomain(const struct ieee80211_regdomain *rd)
{
	BUG_ON(!last_request);

	reset_regdomains();

	cfg80211_world_regdom = rd;
	cfg80211_regdomain = rd;
}

bool is_world_regdom(const char *alpha2)
{
	if (!alpha2)
		return false;
	if (alpha2[0] == '0' && alpha2[1] == '0')
		return true;
	return false;
}

static bool is_alpha2_set(const char *alpha2)
{
	if (!alpha2)
		return false;
	if (alpha2[0] != 0 && alpha2[1] != 0)
		return true;
	return false;
}

static bool is_alpha_upper(char letter)
{
	/* ASCII A - Z */
	if (letter >= 65 && letter <= 90)
		return true;
	return false;
}

static bool is_unknown_alpha2(const char *alpha2)
{
	if (!alpha2)
		return false;
	/* Special case where regulatory domain was built by driver
	 * but a specific alpha2 cannot be determined */
	if (alpha2[0] == '9' && alpha2[1] == '9')
		return true;
	return false;
}

static bool is_an_alpha2(const char *alpha2)
{
	if (!alpha2)
		return false;
	if (is_alpha_upper(alpha2[0]) && is_alpha_upper(alpha2[1]))
		return true;
	return false;
}

static bool alpha2_equal(const char *alpha2_x, const char *alpha2_y)
{
	if (!alpha2_x || !alpha2_y)
		return false;
	if (alpha2_x[0] == alpha2_y[0] &&
		alpha2_x[1] == alpha2_y[1])
		return true;
	return false;
}

static bool regdom_changed(const char *alpha2)
{
	if (!cfg80211_regdomain)
		return true;
	if (alpha2_equal(cfg80211_regdomain->alpha2, alpha2))
		return false;
	return true;
}

/* This lets us keep regulatory code which is updated on a regulatory
 * basis in userspace. */
static int call_crda(const char *alpha2)
{
	char country_env[9 + 2] = "COUNTRY=";
	char *envp[] = {
		country_env,
		NULL
	};

	if (!is_world_regdom((char *) alpha2))
		printk(KERN_INFO "cfg80211: Calling CRDA for country: %c%c\n",
			alpha2[0], alpha2[1]);
	else
		printk(KERN_INFO "cfg80211: Calling CRDA to update world "
			"regulatory domain\n");

	country_env[8] = alpha2[0];
	country_env[9] = alpha2[1];

	return kobject_uevent_env(&reg_pdev->dev.kobj, KOBJ_CHANGE, envp);
}

/* Used by nl80211 before kmalloc'ing our regulatory domain */
bool reg_is_valid_request(const char *alpha2)
{
	if (!last_request)
		return false;

	return alpha2_equal(last_request->alpha2, alpha2);
}

/* Sanity check on a regulatory rule */
static bool is_valid_reg_rule(const struct ieee80211_reg_rule *rule)
{
	const struct ieee80211_freq_range *freq_range = &rule->freq_range;
	u32 freq_diff;

	if (freq_range->start_freq_khz <= 0 || freq_range->end_freq_khz <= 0)
		return false;

	if (freq_range->start_freq_khz > freq_range->end_freq_khz)
		return false;

	freq_diff = freq_range->end_freq_khz - freq_range->start_freq_khz;

	if (freq_diff <= 0 || freq_range->max_bandwidth_khz > freq_diff)
		return false;

	return true;
}

static bool is_valid_rd(const struct ieee80211_regdomain *rd)
{
	const struct ieee80211_reg_rule *reg_rule = NULL;
	unsigned int i;

	if (!rd->n_reg_rules)
		return false;

	for (i = 0; i < rd->n_reg_rules; i++) {
		reg_rule = &rd->reg_rules[i];
		if (!is_valid_reg_rule(reg_rule))
			return false;
	}

	return true;
}

/* Returns value in KHz */
static u32 freq_max_bandwidth(const struct ieee80211_freq_range *freq_range,
	u32 freq)
{
	unsigned int i;
	for (i = 0; i < ARRAY_SIZE(supported_bandwidths); i++) {
		u32 start_freq_khz = freq - supported_bandwidths[i]/2;
		u32 end_freq_khz = freq + supported_bandwidths[i]/2;
		if (start_freq_khz >= freq_range->start_freq_khz &&
			end_freq_khz <= freq_range->end_freq_khz)
			return supported_bandwidths[i];
	}
	return 0;
}

/* Helper for regdom_intersect(), this does the real
 * mathematical intersection fun */
static int reg_rules_intersect(
	const struct ieee80211_reg_rule *rule1,
	const struct ieee80211_reg_rule *rule2,
	struct ieee80211_reg_rule *intersected_rule)
{
	const struct ieee80211_freq_range *freq_range1, *freq_range2;
	struct ieee80211_freq_range *freq_range;
	const struct ieee80211_power_rule *power_rule1, *power_rule2;
	struct ieee80211_power_rule *power_rule;
	u32 freq_diff;

	freq_range1 = &rule1->freq_range;
	freq_range2 = &rule2->freq_range;
	freq_range = &intersected_rule->freq_range;

	power_rule1 = &rule1->power_rule;
	power_rule2 = &rule2->power_rule;
	power_rule = &intersected_rule->power_rule;

	freq_range->start_freq_khz = max(freq_range1->start_freq_khz,
		freq_range2->start_freq_khz);
	freq_range->end_freq_khz = min(freq_range1->end_freq_khz,
		freq_range2->end_freq_khz);
	freq_range->max_bandwidth_khz = min(freq_range1->max_bandwidth_khz,
		freq_range2->max_bandwidth_khz);

	freq_diff = freq_range->end_freq_khz - freq_range->start_freq_khz;
	if (freq_range->max_bandwidth_khz > freq_diff)
		freq_range->max_bandwidth_khz = freq_diff;

	power_rule->max_eirp = min(power_rule1->max_eirp,
		power_rule2->max_eirp);
	power_rule->max_antenna_gain = min(power_rule1->max_antenna_gain,
		power_rule2->max_antenna_gain);

	intersected_rule->flags = (rule1->flags | rule2->flags);

	if (!is_valid_reg_rule(intersected_rule))
		return -EINVAL;

	return 0;
}

/**
 * regdom_intersect - do the intersection between two regulatory domains
 * @rd1: first regulatory domain
 * @rd2: second regulatory domain
 *
 * Use this function to get the intersection between two regulatory domains.
 * Once completed we will mark the alpha2 for the rd as intersected, "98",
 * as no one single alpha2 can represent this regulatory domain.
 *
 * Returns a pointer to the regulatory domain structure which will hold the
 * resulting intersection of rules between rd1 and rd2. We will
 * kzalloc() this structure for you.
 */
static struct ieee80211_regdomain *regdom_intersect(
	const struct ieee80211_regdomain *rd1,
	const struct ieee80211_regdomain *rd2)
{
	int r, size_of_regd;
	unsigned int x, y;
	unsigned int num_rules = 0, rule_idx = 0;
	const struct ieee80211_reg_rule *rule1, *rule2;
	struct ieee80211_reg_rule *intersected_rule;
	struct ieee80211_regdomain *rd;
	/* This is just a dummy holder to help us count */
	struct ieee80211_reg_rule irule;

	/* Uses the stack temporarily for counter arithmetic */
	intersected_rule = &irule;

	memset(intersected_rule, 0, sizeof(struct ieee80211_reg_rule));

	if (!rd1 || !rd2)
		return NULL;

	/* First we get a count of the rules we'll need, then we actually
	 * build them. This is to so we can malloc() and free() a
	 * regdomain once. The reason we use reg_rules_intersect() here
	 * is it will return -EINVAL if the rule computed makes no sense.
	 * All rules that do check out OK are valid. */

	for (x = 0; x < rd1->n_reg_rules; x++) {
		rule1 = &rd1->reg_rules[x];
		for (y = 0; y < rd2->n_reg_rules; y++) {
			rule2 = &rd2->reg_rules[y];
			if (!reg_rules_intersect(rule1, rule2,
					intersected_rule))
				num_rules++;
			memset(intersected_rule, 0,
					sizeof(struct ieee80211_reg_rule));
		}
	}

	if (!num_rules)
		return NULL;

	size_of_regd = sizeof(struct ieee80211_regdomain) +
		((num_rules + 1) * sizeof(struct ieee80211_reg_rule));

	rd = kzalloc(size_of_regd, GFP_KERNEL);
	if (!rd)
		return NULL;

	for (x = 0; x < rd1->n_reg_rules; x++) {
		rule1 = &rd1->reg_rules[x];
		for (y = 0; y < rd2->n_reg_rules; y++) {
			rule2 = &rd2->reg_rules[y];
			/* This time around instead of using the stack lets
			 * write to the target rule directly saving ourselves
			 * a memcpy() */
			intersected_rule = &rd->reg_rules[rule_idx];
			r = reg_rules_intersect(rule1, rule2,
				intersected_rule);
			/* No need to memset here the intersected rule here as
			 * we're not using the stack anymore */
			if (r)
				continue;
			rule_idx++;
		}
	}

	if (rule_idx != num_rules) {
		kfree(rd);
		return NULL;
	}

	rd->n_reg_rules = num_rules;
	rd->alpha2[0] = '9';
	rd->alpha2[1] = '8';

	return rd;
}

/* XXX: add support for the rest of enum nl80211_reg_rule_flags, we may
 * want to just have the channel structure use these */
static u32 map_regdom_flags(u32 rd_flags)
{
	u32 channel_flags = 0;
	if (rd_flags & NL80211_RRF_PASSIVE_SCAN)
		channel_flags |= IEEE80211_CHAN_PASSIVE_SCAN;
	if (rd_flags & NL80211_RRF_NO_IBSS)
		channel_flags |= IEEE80211_CHAN_NO_IBSS;
	if (rd_flags & NL80211_RRF_DFS)
		channel_flags |= IEEE80211_CHAN_RADAR;
	return channel_flags;
}

/**
 * freq_reg_info - get regulatory information for the given frequency
 * @center_freq: Frequency in KHz for which we want regulatory information for
 * @bandwidth: the bandwidth requirement you have in KHz, if you do not have one
 * 	you can set this to 0. If this frequency is allowed we then set
 * 	this value to the maximum allowed bandwidth.
 * @reg_rule: the regulatory rule which we have for this frequency
 *
 * Use this function to get the regulatory rule for a specific frequency.
 */
static int freq_reg_info(u32 center_freq, u32 *bandwidth,
			 const struct ieee80211_reg_rule **reg_rule)
{
	int i;
	u32 max_bandwidth = 0;

	if (!cfg80211_regdomain)
		return -EINVAL;

	for (i = 0; i < cfg80211_regdomain->n_reg_rules; i++) {
		const struct ieee80211_reg_rule *rr;
		const struct ieee80211_freq_range *fr = NULL;
		const struct ieee80211_power_rule *pr = NULL;

		rr = &cfg80211_regdomain->reg_rules[i];
		fr = &rr->freq_range;
		pr = &rr->power_rule;
		max_bandwidth = freq_max_bandwidth(fr, center_freq);
		if (max_bandwidth && *bandwidth <= max_bandwidth) {
			*reg_rule = rr;
			*bandwidth = max_bandwidth;
			break;
		}
	}

	return !max_bandwidth;
}

static void handle_channel(struct ieee80211_channel *chan)
{
	int r;
	u32 flags = chan->orig_flags;
	u32 max_bandwidth = 0;
	const struct ieee80211_reg_rule *reg_rule = NULL;
	const struct ieee80211_power_rule *power_rule = NULL;

	r = freq_reg_info(MHZ_TO_KHZ(chan->center_freq),
		&max_bandwidth, &reg_rule);

	if (r) {
		flags |= IEEE80211_CHAN_DISABLED;
		chan->flags = flags;
		return;
	}

	power_rule = &reg_rule->power_rule;

	chan->flags = flags | map_regdom_flags(reg_rule->flags);
	chan->max_antenna_gain = min(chan->orig_mag,
		(int) MBI_TO_DBI(power_rule->max_antenna_gain));
	chan->max_bandwidth = KHZ_TO_MHZ(max_bandwidth);
	if (chan->orig_mpwr)
		chan->max_power = min(chan->orig_mpwr,
			(int) MBM_TO_DBM(power_rule->max_eirp));
	else
		chan->max_power = (int) MBM_TO_DBM(power_rule->max_eirp);
}

static void handle_band(struct ieee80211_supported_band *sband)
{
	int i;

	for (i = 0; i < sband->n_channels; i++)
		handle_channel(&sband->channels[i]);
}

static void update_all_wiphy_regulatory(enum reg_set_by setby)
{
	struct cfg80211_registered_device *drv;

	list_for_each_entry(drv, &cfg80211_drv_list, list)
		wiphy_update_regulatory(&drv->wiphy, setby);
}

void wiphy_update_regulatory(struct wiphy *wiphy, enum reg_set_by setby)
{
	enum ieee80211_band band;
	for (band = 0; band < IEEE80211_NUM_BANDS; band++) {
		if (wiphy->bands[band])
			handle_band(wiphy->bands[band]);
		if (wiphy->reg_notifier)
			wiphy->reg_notifier(wiphy, setby);
	}
}

/* Return value which can be used by ignore_request() to indicate
 * it has been determined we should intersect two regulatory domains */
#define REG_INTERSECT	1

/* This has the logic which determines when a new request
 * should be ignored. */
static int ignore_request(struct wiphy *wiphy, enum reg_set_by set_by,
			  const char *alpha2)
{
	/* All initial requests are respected */
	if (!last_request)
		return 0;

	switch (set_by) {
	case REGDOM_SET_BY_INIT:
		return -EINVAL;
	case REGDOM_SET_BY_CORE:
		/*
		 * Always respect new wireless core hints, should only happen
		 * when updating the world regulatory domain at init.
		 */
		return 0;
	case REGDOM_SET_BY_COUNTRY_IE:
		if (unlikely(!is_an_alpha2(alpha2)))
			return -EINVAL;
		if (last_request->initiator == REGDOM_SET_BY_COUNTRY_IE) {
			if (last_request->wiphy != wiphy) {
				/*
				 * Two cards with two APs claiming different
				 * different Country IE alpha2s. We could
				 * intersect them, but that seems unlikely
				 * to be correct. Reject second one for now.
				 */
				if (!alpha2_equal(alpha2,
						  cfg80211_regdomain->alpha2))
					return -EOPNOTSUPP;
				return -EALREADY;
			}
			/* Two consecutive Country IE hints on the same wiphy */
			if (!alpha2_equal(cfg80211_regdomain->alpha2, alpha2))
				return 0;
			return -EALREADY;
		}
		/*
		 * Ignore Country IE hints for now, need to think about
		 * what we need to do to support multi-domain operation.
		 */
		return -EOPNOTSUPP;
	case REGDOM_SET_BY_DRIVER:
		if (last_request->initiator == REGDOM_SET_BY_DRIVER)
			return -EALREADY;
		return 0;
	case REGDOM_SET_BY_USER:
		if (last_request->initiator == REGDOM_SET_BY_COUNTRY_IE)
			return REG_INTERSECT;
		return 0;
	}

	return -EINVAL;
}

/* Caller must hold &cfg80211_drv_mutex */
int __regulatory_hint(struct wiphy *wiphy, enum reg_set_by set_by,
		      const char *alpha2)
{
	struct regulatory_request *request;
	bool intersect = false;
	int r = 0;

	r = ignore_request(wiphy, set_by, alpha2);

	if (r == REG_INTERSECT)
		intersect = true;
	else if (r)
		return r;

	request = kzalloc(sizeof(struct regulatory_request),
			  GFP_KERNEL);
	if (!request)
		return -ENOMEM;

	request->alpha2[0] = alpha2[0];
	request->alpha2[1] = alpha2[1];
	request->initiator = set_by;
	request->wiphy = wiphy;
	request->intersect = intersect;

	kfree(last_request);
	last_request = request;
	r = call_crda(alpha2);

#ifndef CONFIG_WIRELESS_OLD_REGULATORY
	if (r)
		printk(KERN_ERR "cfg80211: Failed calling CRDA\n");
#endif

	return r;
}

void regulatory_hint(struct wiphy *wiphy, const char *alpha2)
{
	BUG_ON(!alpha2);

	mutex_lock(&cfg80211_drv_mutex);
	__regulatory_hint(wiphy, REGDOM_SET_BY_DRIVER, alpha2);
	mutex_unlock(&cfg80211_drv_mutex);
}
EXPORT_SYMBOL(regulatory_hint);


static void print_rd_rules(const struct ieee80211_regdomain *rd)
{
	unsigned int i;
	const struct ieee80211_reg_rule *reg_rule = NULL;
	const struct ieee80211_freq_range *freq_range = NULL;
	const struct ieee80211_power_rule *power_rule = NULL;

	printk(KERN_INFO "\t(start_freq - end_freq @ bandwidth), "
		"(max_antenna_gain, max_eirp)\n");

	for (i = 0; i < rd->n_reg_rules; i++) {
		reg_rule = &rd->reg_rules[i];
		freq_range = &reg_rule->freq_range;
		power_rule = &reg_rule->power_rule;

		/* There may not be documentation for max antenna gain
		 * in certain regions */
		if (power_rule->max_antenna_gain)
			printk(KERN_INFO "\t(%d KHz - %d KHz @ %d KHz), "
				"(%d mBi, %d mBm)\n",
				freq_range->start_freq_khz,
				freq_range->end_freq_khz,
				freq_range->max_bandwidth_khz,
				power_rule->max_antenna_gain,
				power_rule->max_eirp);
		else
			printk(KERN_INFO "\t(%d KHz - %d KHz @ %d KHz), "
				"(N/A, %d mBm)\n",
				freq_range->start_freq_khz,
				freq_range->end_freq_khz,
				freq_range->max_bandwidth_khz,
				power_rule->max_eirp);
	}
}

static void print_regdomain(const struct ieee80211_regdomain *rd)
{

	if (is_world_regdom(rd->alpha2))
		printk(KERN_INFO "cfg80211: World regulatory "
			"domain updated:\n");
	else {
		if (is_unknown_alpha2(rd->alpha2))
			printk(KERN_INFO "cfg80211: Regulatory domain "
				"changed to driver built-in settings "
				"(unknown country)\n");
		else
			printk(KERN_INFO "cfg80211: Regulatory domain "
				"changed to country: %c%c\n",
				rd->alpha2[0], rd->alpha2[1]);
	}
	print_rd_rules(rd);
}

static void print_regdomain_info(const struct ieee80211_regdomain *rd)
{
	printk(KERN_INFO "cfg80211: Regulatory domain: %c%c\n",
		rd->alpha2[0], rd->alpha2[1]);
	print_rd_rules(rd);
}

/* Takes ownership of rd only if it doesn't fail */
static int __set_regdom(const struct ieee80211_regdomain *rd)
{
	const struct ieee80211_regdomain *intersected_rd = NULL;
	/* Some basic sanity checks first */

	if (is_world_regdom(rd->alpha2)) {
		if (WARN_ON(!reg_is_valid_request(rd->alpha2)))
			return -EINVAL;
		update_world_regdomain(rd);
		return 0;
	}

	if (!is_alpha2_set(rd->alpha2) && !is_an_alpha2(rd->alpha2) &&
			!is_unknown_alpha2(rd->alpha2))
		return -EINVAL;

	if (!last_request)
		return -EINVAL;

	/* allow overriding the static definitions if CRDA is present */
	if (!is_old_static_regdom(cfg80211_regdomain) &&
	    !regdom_changed(rd->alpha2))
		return -EINVAL;

	/* Now lets set the regulatory domain, update all driver channels
	 * and finally inform them of what we have done, in case they want
	 * to review or adjust their own settings based on their own
	 * internal EEPROM data */

	if (WARN_ON(!reg_is_valid_request(rd->alpha2)))
		return -EINVAL;

	reset_regdomains();

	/* Country IE parsing coming soon */

	if (!is_valid_rd(rd)) {
		printk(KERN_ERR "cfg80211: Invalid "
			"regulatory domain detected:\n");
		print_regdomain_info(rd);
		return -EINVAL;
	}

	if (unlikely(last_request->intersect)) {
		intersected_rd = regdom_intersect(rd, cfg80211_regdomain);
		if (!intersected_rd)
			return -EINVAL;
		kfree(rd);
		rd = intersected_rd;
	}

	/* Tada! */
	cfg80211_regdomain = rd;

	return 0;
}


/* Use this call to set the current regulatory domain. Conflicts with
 * multiple drivers can be ironed out later. Caller must've already
 * kmalloc'd the rd structure. Caller must hold cfg80211_drv_mutex */
int set_regdom(const struct ieee80211_regdomain *rd)
{
	int r;

	/* Note that this doesn't update the wiphys, this is done below */
	r = __set_regdom(rd);
	if (r) {
		kfree(rd);
		return r;
	}

	/* This would make this whole thing pointless */
	BUG_ON(rd != cfg80211_regdomain);

	/* update all wiphys now with the new established regulatory domain */
	update_all_wiphy_regulatory(last_request->initiator);

	print_regdomain(rd);

	return r;
}

int regulatory_init(void)
{
	int err;

	reg_pdev = platform_device_register_simple("regulatory", 0, NULL, 0);
	if (IS_ERR(reg_pdev))
		return PTR_ERR(reg_pdev);

#ifdef CONFIG_WIRELESS_OLD_REGULATORY
	cfg80211_regdomain = static_regdom(ieee80211_regdom);

	printk(KERN_INFO "cfg80211: Using static regulatory domain info\n");
	print_regdomain_info(cfg80211_regdomain);
	/* The old code still requests for a new regdomain and if
	 * you have CRDA you get it updated, otherwise you get
	 * stuck with the static values. We ignore "EU" code as
	 * that is not a valid ISO / IEC 3166 alpha2 */
	if (ieee80211_regdom[0] != 'E' || ieee80211_regdom[1] != 'U')
		err = __regulatory_hint(NULL, REGDOM_SET_BY_CORE,
					ieee80211_regdom);
#else
	cfg80211_regdomain = cfg80211_world_regdom;

	err = __regulatory_hint(NULL, REGDOM_SET_BY_CORE, "00");
	if (err)
		printk(KERN_ERR "cfg80211: calling CRDA failed - "
		       "unable to update world regulatory domain, "
		       "using static definition\n");
#endif

	return 0;
}

void regulatory_exit(void)
{
	mutex_lock(&cfg80211_drv_mutex);

	reset_regdomains();

	kfree(last_request);

	platform_device_unregister(reg_pdev);

	mutex_unlock(&cfg80211_drv_mutex);
}