mac80211: clean up ieee80211_hw_config errors
[pandora-kernel.git] / net / mac80211 / util.c
1 /*
2  * Copyright 2002-2005, Instant802 Networks, Inc.
3  * Copyright 2005-2006, Devicescape Software, Inc.
4  * Copyright 2006-2007  Jiri Benc <jbenc@suse.cz>
5  * Copyright 2007       Johannes Berg <johannes@sipsolutions.net>
6  *
7  * This program is free software; you can redistribute it and/or modify
8  * it under the terms of the GNU General Public License version 2 as
9  * published by the Free Software Foundation.
10  *
11  * utilities for mac80211
12  */
13
14 #include <net/mac80211.h>
15 #include <linux/netdevice.h>
16 #include <linux/types.h>
17 #include <linux/slab.h>
18 #include <linux/skbuff.h>
19 #include <linux/etherdevice.h>
20 #include <linux/if_arp.h>
21 #include <linux/wireless.h>
22 #include <linux/bitmap.h>
23 #include <net/net_namespace.h>
24 #include <net/cfg80211.h>
25 #include <net/rtnetlink.h>
26
27 #include "ieee80211_i.h"
28 #include "rate.h"
29 #include "mesh.h"
30 #include "wme.h"
31
32 /* privid for wiphys to determine whether they belong to us or not */
33 void *mac80211_wiphy_privid = &mac80211_wiphy_privid;
34
35 /* See IEEE 802.1H for LLC/SNAP encapsulation/decapsulation */
36 /* Ethernet-II snap header (RFC1042 for most EtherTypes) */
37 const unsigned char rfc1042_header[] __aligned(2) =
38         { 0xaa, 0xaa, 0x03, 0x00, 0x00, 0x00 };
39
40 /* Bridge-Tunnel header (for EtherTypes ETH_P_AARP and ETH_P_IPX) */
41 const unsigned char bridge_tunnel_header[] __aligned(2) =
42         { 0xaa, 0xaa, 0x03, 0x00, 0x00, 0xf8 };
43
44
45 u8 *ieee80211_get_bssid(struct ieee80211_hdr *hdr, size_t len,
46                         enum nl80211_iftype type)
47 {
48         __le16 fc = hdr->frame_control;
49
50          /* drop ACK/CTS frames and incorrect hdr len (ctrl) */
51         if (len < 16)
52                 return NULL;
53
54         if (ieee80211_is_data(fc)) {
55                 if (len < 24) /* drop incorrect hdr len (data) */
56                         return NULL;
57
58                 if (ieee80211_has_a4(fc))
59                         return NULL;
60                 if (ieee80211_has_tods(fc))
61                         return hdr->addr1;
62                 if (ieee80211_has_fromds(fc))
63                         return hdr->addr2;
64
65                 return hdr->addr3;
66         }
67
68         if (ieee80211_is_mgmt(fc)) {
69                 if (len < 24) /* drop incorrect hdr len (mgmt) */
70                         return NULL;
71                 return hdr->addr3;
72         }
73
74         if (ieee80211_is_ctl(fc)) {
75                 if(ieee80211_is_pspoll(fc))
76                         return hdr->addr1;
77
78                 if (ieee80211_is_back_req(fc)) {
79                         switch (type) {
80                         case NL80211_IFTYPE_STATION:
81                                 return hdr->addr2;
82                         case NL80211_IFTYPE_AP:
83                         case NL80211_IFTYPE_AP_VLAN:
84                                 return hdr->addr1;
85                         default:
86                                 break; /* fall through to the return */
87                         }
88                 }
89         }
90
91         return NULL;
92 }
93
94 unsigned int ieee80211_hdrlen(__le16 fc)
95 {
96         unsigned int hdrlen = 24;
97
98         if (ieee80211_is_data(fc)) {
99                 if (ieee80211_has_a4(fc))
100                         hdrlen = 30;
101                 if (ieee80211_is_data_qos(fc))
102                         hdrlen += IEEE80211_QOS_CTL_LEN;
103                 goto out;
104         }
105
106         if (ieee80211_is_ctl(fc)) {
107                 /*
108                  * ACK and CTS are 10 bytes, all others 16. To see how
109                  * to get this condition consider
110                  *   subtype mask:   0b0000000011110000 (0x00F0)
111                  *   ACK subtype:    0b0000000011010000 (0x00D0)
112                  *   CTS subtype:    0b0000000011000000 (0x00C0)
113                  *   bits that matter:         ^^^      (0x00E0)
114                  *   value of those: 0b0000000011000000 (0x00C0)
115                  */
116                 if ((fc & cpu_to_le16(0x00E0)) == cpu_to_le16(0x00C0))
117                         hdrlen = 10;
118                 else
119                         hdrlen = 16;
120         }
121 out:
122         return hdrlen;
123 }
124 EXPORT_SYMBOL(ieee80211_hdrlen);
125
126 unsigned int ieee80211_get_hdrlen_from_skb(const struct sk_buff *skb)
127 {
128         const struct ieee80211_hdr *hdr = (const struct ieee80211_hdr *)skb->data;
129         unsigned int hdrlen;
130
131         if (unlikely(skb->len < 10))
132                 return 0;
133         hdrlen = ieee80211_hdrlen(hdr->frame_control);
134         if (unlikely(hdrlen > skb->len))
135                 return 0;
136         return hdrlen;
137 }
138 EXPORT_SYMBOL(ieee80211_get_hdrlen_from_skb);
139
140 int ieee80211_get_mesh_hdrlen(struct ieee80211s_hdr *meshhdr)
141 {
142         int ae = meshhdr->flags & IEEE80211S_FLAGS_AE;
143         /* 7.1.3.5a.2 */
144         switch (ae) {
145         case 0:
146                 return 6;
147         case 1:
148                 return 12;
149         case 2:
150                 return 18;
151         case 3:
152                 return 24;
153         default:
154                 return 6;
155         }
156 }
157
158 void ieee80211_tx_set_protected(struct ieee80211_tx_data *tx)
159 {
160         struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) tx->skb->data;
161
162         hdr->frame_control |= cpu_to_le16(IEEE80211_FCTL_PROTECTED);
163         if (tx->extra_frag) {
164                 struct ieee80211_hdr *fhdr;
165                 int i;
166                 for (i = 0; i < tx->num_extra_frag; i++) {
167                         fhdr = (struct ieee80211_hdr *)
168                                 tx->extra_frag[i]->data;
169                         fhdr->frame_control |= cpu_to_le16(IEEE80211_FCTL_PROTECTED);
170                 }
171         }
172 }
173
174 int ieee80211_frame_duration(struct ieee80211_local *local, size_t len,
175                              int rate, int erp, int short_preamble)
176 {
177         int dur;
178
179         /* calculate duration (in microseconds, rounded up to next higher
180          * integer if it includes a fractional microsecond) to send frame of
181          * len bytes (does not include FCS) at the given rate. Duration will
182          * also include SIFS.
183          *
184          * rate is in 100 kbps, so divident is multiplied by 10 in the
185          * DIV_ROUND_UP() operations.
186          */
187
188         if (local->hw.conf.channel->band == IEEE80211_BAND_5GHZ || erp) {
189                 /*
190                  * OFDM:
191                  *
192                  * N_DBPS = DATARATE x 4
193                  * N_SYM = Ceiling((16+8xLENGTH+6) / N_DBPS)
194                  *      (16 = SIGNAL time, 6 = tail bits)
195                  * TXTIME = T_PREAMBLE + T_SIGNAL + T_SYM x N_SYM + Signal Ext
196                  *
197                  * T_SYM = 4 usec
198                  * 802.11a - 17.5.2: aSIFSTime = 16 usec
199                  * 802.11g - 19.8.4: aSIFSTime = 10 usec +
200                  *      signal ext = 6 usec
201                  */
202                 dur = 16; /* SIFS + signal ext */
203                 dur += 16; /* 17.3.2.3: T_PREAMBLE = 16 usec */
204                 dur += 4; /* 17.3.2.3: T_SIGNAL = 4 usec */
205                 dur += 4 * DIV_ROUND_UP((16 + 8 * (len + 4) + 6) * 10,
206                                         4 * rate); /* T_SYM x N_SYM */
207         } else {
208                 /*
209                  * 802.11b or 802.11g with 802.11b compatibility:
210                  * 18.3.4: TXTIME = PreambleLength + PLCPHeaderTime +
211                  * Ceiling(((LENGTH+PBCC)x8)/DATARATE). PBCC=0.
212                  *
213                  * 802.11 (DS): 15.3.3, 802.11b: 18.3.4
214                  * aSIFSTime = 10 usec
215                  * aPreambleLength = 144 usec or 72 usec with short preamble
216                  * aPLCPHeaderLength = 48 usec or 24 usec with short preamble
217                  */
218                 dur = 10; /* aSIFSTime = 10 usec */
219                 dur += short_preamble ? (72 + 24) : (144 + 48);
220
221                 dur += DIV_ROUND_UP(8 * (len + 4) * 10, rate);
222         }
223
224         return dur;
225 }
226
227 /* Exported duration function for driver use */
228 __le16 ieee80211_generic_frame_duration(struct ieee80211_hw *hw,
229                                         struct ieee80211_vif *vif,
230                                         size_t frame_len,
231                                         struct ieee80211_rate *rate)
232 {
233         struct ieee80211_local *local = hw_to_local(hw);
234         struct ieee80211_sub_if_data *sdata;
235         u16 dur;
236         int erp;
237         bool short_preamble = false;
238
239         erp = 0;
240         if (vif) {
241                 sdata = vif_to_sdata(vif);
242                 short_preamble = sdata->bss_conf.use_short_preamble;
243                 if (sdata->flags & IEEE80211_SDATA_OPERATING_GMODE)
244                         erp = rate->flags & IEEE80211_RATE_ERP_G;
245         }
246
247         dur = ieee80211_frame_duration(local, frame_len, rate->bitrate, erp,
248                                        short_preamble);
249
250         return cpu_to_le16(dur);
251 }
252 EXPORT_SYMBOL(ieee80211_generic_frame_duration);
253
254 __le16 ieee80211_rts_duration(struct ieee80211_hw *hw,
255                               struct ieee80211_vif *vif, size_t frame_len,
256                               const struct ieee80211_tx_info *frame_txctl)
257 {
258         struct ieee80211_local *local = hw_to_local(hw);
259         struct ieee80211_rate *rate;
260         struct ieee80211_sub_if_data *sdata;
261         bool short_preamble;
262         int erp;
263         u16 dur;
264         struct ieee80211_supported_band *sband;
265
266         sband = local->hw.wiphy->bands[local->hw.conf.channel->band];
267
268         short_preamble = false;
269
270         rate = &sband->bitrates[frame_txctl->control.rts_cts_rate_idx];
271
272         erp = 0;
273         if (vif) {
274                 sdata = vif_to_sdata(vif);
275                 short_preamble = sdata->bss_conf.use_short_preamble;
276                 if (sdata->flags & IEEE80211_SDATA_OPERATING_GMODE)
277                         erp = rate->flags & IEEE80211_RATE_ERP_G;
278         }
279
280         /* CTS duration */
281         dur = ieee80211_frame_duration(local, 10, rate->bitrate,
282                                        erp, short_preamble);
283         /* Data frame duration */
284         dur += ieee80211_frame_duration(local, frame_len, rate->bitrate,
285                                         erp, short_preamble);
286         /* ACK duration */
287         dur += ieee80211_frame_duration(local, 10, rate->bitrate,
288                                         erp, short_preamble);
289
290         return cpu_to_le16(dur);
291 }
292 EXPORT_SYMBOL(ieee80211_rts_duration);
293
294 __le16 ieee80211_ctstoself_duration(struct ieee80211_hw *hw,
295                                     struct ieee80211_vif *vif,
296                                     size_t frame_len,
297                                     const struct ieee80211_tx_info *frame_txctl)
298 {
299         struct ieee80211_local *local = hw_to_local(hw);
300         struct ieee80211_rate *rate;
301         struct ieee80211_sub_if_data *sdata;
302         bool short_preamble;
303         int erp;
304         u16 dur;
305         struct ieee80211_supported_band *sband;
306
307         sband = local->hw.wiphy->bands[local->hw.conf.channel->band];
308
309         short_preamble = false;
310
311         rate = &sband->bitrates[frame_txctl->control.rts_cts_rate_idx];
312         erp = 0;
313         if (vif) {
314                 sdata = vif_to_sdata(vif);
315                 short_preamble = sdata->bss_conf.use_short_preamble;
316                 if (sdata->flags & IEEE80211_SDATA_OPERATING_GMODE)
317                         erp = rate->flags & IEEE80211_RATE_ERP_G;
318         }
319
320         /* Data frame duration */
321         dur = ieee80211_frame_duration(local, frame_len, rate->bitrate,
322                                        erp, short_preamble);
323         if (!(frame_txctl->flags & IEEE80211_TX_CTL_NO_ACK)) {
324                 /* ACK duration */
325                 dur += ieee80211_frame_duration(local, 10, rate->bitrate,
326                                                 erp, short_preamble);
327         }
328
329         return cpu_to_le16(dur);
330 }
331 EXPORT_SYMBOL(ieee80211_ctstoself_duration);
332
333 void ieee80211_wake_queue(struct ieee80211_hw *hw, int queue)
334 {
335         struct ieee80211_local *local = hw_to_local(hw);
336
337         if (test_bit(queue, local->queues_pending)) {
338                 set_bit(queue, local->queues_pending_run);
339                 tasklet_schedule(&local->tx_pending_tasklet);
340         } else {
341                 netif_wake_subqueue(local->mdev, queue);
342         }
343 }
344 EXPORT_SYMBOL(ieee80211_wake_queue);
345
346 void ieee80211_stop_queue(struct ieee80211_hw *hw, int queue)
347 {
348         struct ieee80211_local *local = hw_to_local(hw);
349
350         netif_stop_subqueue(local->mdev, queue);
351 }
352 EXPORT_SYMBOL(ieee80211_stop_queue);
353
354 void ieee80211_stop_queues(struct ieee80211_hw *hw)
355 {
356         int i;
357
358         for (i = 0; i < ieee80211_num_queues(hw); i++)
359                 ieee80211_stop_queue(hw, i);
360 }
361 EXPORT_SYMBOL(ieee80211_stop_queues);
362
363 int ieee80211_queue_stopped(struct ieee80211_hw *hw, int queue)
364 {
365         struct ieee80211_local *local = hw_to_local(hw);
366         return __netif_subqueue_stopped(local->mdev, queue);
367 }
368 EXPORT_SYMBOL(ieee80211_queue_stopped);
369
370 void ieee80211_wake_queues(struct ieee80211_hw *hw)
371 {
372         int i;
373
374         for (i = 0; i < hw->queues + hw->ampdu_queues; i++)
375                 ieee80211_wake_queue(hw, i);
376 }
377 EXPORT_SYMBOL(ieee80211_wake_queues);
378
379 void ieee80211_iterate_active_interfaces(
380         struct ieee80211_hw *hw,
381         void (*iterator)(void *data, u8 *mac,
382                          struct ieee80211_vif *vif),
383         void *data)
384 {
385         struct ieee80211_local *local = hw_to_local(hw);
386         struct ieee80211_sub_if_data *sdata;
387
388         rtnl_lock();
389
390         list_for_each_entry(sdata, &local->interfaces, list) {
391                 switch (sdata->vif.type) {
392                 case __NL80211_IFTYPE_AFTER_LAST:
393                 case NL80211_IFTYPE_UNSPECIFIED:
394                 case NL80211_IFTYPE_MONITOR:
395                 case NL80211_IFTYPE_AP_VLAN:
396                         continue;
397                 case NL80211_IFTYPE_AP:
398                 case NL80211_IFTYPE_STATION:
399                 case NL80211_IFTYPE_ADHOC:
400                 case NL80211_IFTYPE_WDS:
401                 case NL80211_IFTYPE_MESH_POINT:
402                         break;
403                 }
404                 if (netif_running(sdata->dev))
405                         iterator(data, sdata->dev->dev_addr,
406                                  &sdata->vif);
407         }
408
409         rtnl_unlock();
410 }
411 EXPORT_SYMBOL_GPL(ieee80211_iterate_active_interfaces);
412
413 void ieee80211_iterate_active_interfaces_atomic(
414         struct ieee80211_hw *hw,
415         void (*iterator)(void *data, u8 *mac,
416                          struct ieee80211_vif *vif),
417         void *data)
418 {
419         struct ieee80211_local *local = hw_to_local(hw);
420         struct ieee80211_sub_if_data *sdata;
421
422         rcu_read_lock();
423
424         list_for_each_entry_rcu(sdata, &local->interfaces, list) {
425                 switch (sdata->vif.type) {
426                 case __NL80211_IFTYPE_AFTER_LAST:
427                 case NL80211_IFTYPE_UNSPECIFIED:
428                 case NL80211_IFTYPE_MONITOR:
429                 case NL80211_IFTYPE_AP_VLAN:
430                         continue;
431                 case NL80211_IFTYPE_AP:
432                 case NL80211_IFTYPE_STATION:
433                 case NL80211_IFTYPE_ADHOC:
434                 case NL80211_IFTYPE_WDS:
435                 case NL80211_IFTYPE_MESH_POINT:
436                         break;
437                 }
438                 if (netif_running(sdata->dev))
439                         iterator(data, sdata->dev->dev_addr,
440                                  &sdata->vif);
441         }
442
443         rcu_read_unlock();
444 }
445 EXPORT_SYMBOL_GPL(ieee80211_iterate_active_interfaces_atomic);
446
447 void ieee802_11_parse_elems(u8 *start, size_t len,
448                             struct ieee802_11_elems *elems)
449 {
450         size_t left = len;
451         u8 *pos = start;
452
453         memset(elems, 0, sizeof(*elems));
454         elems->ie_start = start;
455         elems->total_len = len;
456
457         while (left >= 2) {
458                 u8 id, elen;
459
460                 id = *pos++;
461                 elen = *pos++;
462                 left -= 2;
463
464                 if (elen > left)
465                         return;
466
467                 switch (id) {
468                 case WLAN_EID_SSID:
469                         elems->ssid = pos;
470                         elems->ssid_len = elen;
471                         break;
472                 case WLAN_EID_SUPP_RATES:
473                         elems->supp_rates = pos;
474                         elems->supp_rates_len = elen;
475                         break;
476                 case WLAN_EID_FH_PARAMS:
477                         elems->fh_params = pos;
478                         elems->fh_params_len = elen;
479                         break;
480                 case WLAN_EID_DS_PARAMS:
481                         elems->ds_params = pos;
482                         elems->ds_params_len = elen;
483                         break;
484                 case WLAN_EID_CF_PARAMS:
485                         elems->cf_params = pos;
486                         elems->cf_params_len = elen;
487                         break;
488                 case WLAN_EID_TIM:
489                         elems->tim = pos;
490                         elems->tim_len = elen;
491                         break;
492                 case WLAN_EID_IBSS_PARAMS:
493                         elems->ibss_params = pos;
494                         elems->ibss_params_len = elen;
495                         break;
496                 case WLAN_EID_CHALLENGE:
497                         elems->challenge = pos;
498                         elems->challenge_len = elen;
499                         break;
500                 case WLAN_EID_WPA:
501                         if (elen >= 4 && pos[0] == 0x00 && pos[1] == 0x50 &&
502                             pos[2] == 0xf2) {
503                                 /* Microsoft OUI (00:50:F2) */
504                                 if (pos[3] == 1) {
505                                         /* OUI Type 1 - WPA IE */
506                                         elems->wpa = pos;
507                                         elems->wpa_len = elen;
508                                 } else if (elen >= 5 && pos[3] == 2) {
509                                         if (pos[4] == 0) {
510                                                 elems->wmm_info = pos;
511                                                 elems->wmm_info_len = elen;
512                                         } else if (pos[4] == 1) {
513                                                 elems->wmm_param = pos;
514                                                 elems->wmm_param_len = elen;
515                                         }
516                                 }
517                         }
518                         break;
519                 case WLAN_EID_RSN:
520                         elems->rsn = pos;
521                         elems->rsn_len = elen;
522                         break;
523                 case WLAN_EID_ERP_INFO:
524                         elems->erp_info = pos;
525                         elems->erp_info_len = elen;
526                         break;
527                 case WLAN_EID_EXT_SUPP_RATES:
528                         elems->ext_supp_rates = pos;
529                         elems->ext_supp_rates_len = elen;
530                         break;
531                 case WLAN_EID_HT_CAPABILITY:
532                         if (elen >= sizeof(struct ieee80211_ht_cap))
533                                 elems->ht_cap_elem = (void *)pos;
534                         break;
535                 case WLAN_EID_HT_EXTRA_INFO:
536                         if (elen >= sizeof(struct ieee80211_ht_addt_info))
537                                 elems->ht_info_elem = (void *)pos;
538                         break;
539                 case WLAN_EID_MESH_ID:
540                         elems->mesh_id = pos;
541                         elems->mesh_id_len = elen;
542                         break;
543                 case WLAN_EID_MESH_CONFIG:
544                         elems->mesh_config = pos;
545                         elems->mesh_config_len = elen;
546                         break;
547                 case WLAN_EID_PEER_LINK:
548                         elems->peer_link = pos;
549                         elems->peer_link_len = elen;
550                         break;
551                 case WLAN_EID_PREQ:
552                         elems->preq = pos;
553                         elems->preq_len = elen;
554                         break;
555                 case WLAN_EID_PREP:
556                         elems->prep = pos;
557                         elems->prep_len = elen;
558                         break;
559                 case WLAN_EID_PERR:
560                         elems->perr = pos;
561                         elems->perr_len = elen;
562                         break;
563                 case WLAN_EID_CHANNEL_SWITCH:
564                         elems->ch_switch_elem = pos;
565                         elems->ch_switch_elem_len = elen;
566                         break;
567                 case WLAN_EID_QUIET:
568                         if (!elems->quiet_elem) {
569                                 elems->quiet_elem = pos;
570                                 elems->quiet_elem_len = elen;
571                         }
572                         elems->num_of_quiet_elem++;
573                         break;
574                 case WLAN_EID_COUNTRY:
575                         elems->country_elem = pos;
576                         elems->country_elem_len = elen;
577                         break;
578                 case WLAN_EID_PWR_CONSTRAINT:
579                         elems->pwr_constr_elem = pos;
580                         elems->pwr_constr_elem_len = elen;
581                         break;
582                 default:
583                         break;
584                 }
585
586                 left -= elen;
587                 pos += elen;
588         }
589 }
590
591 void ieee80211_set_wmm_default(struct ieee80211_sub_if_data *sdata)
592 {
593         struct ieee80211_local *local = sdata->local;
594         struct ieee80211_tx_queue_params qparam;
595         int i;
596
597         if (!local->ops->conf_tx)
598                 return;
599
600         memset(&qparam, 0, sizeof(qparam));
601
602         qparam.aifs = 2;
603
604         if (local->hw.conf.channel->band == IEEE80211_BAND_2GHZ &&
605             !(sdata->flags & IEEE80211_SDATA_OPERATING_GMODE))
606                 qparam.cw_min = 31;
607         else
608                 qparam.cw_min = 15;
609
610         qparam.cw_max = 1023;
611         qparam.txop = 0;
612
613         for (i = 0; i < local_to_hw(local)->queues; i++)
614                 local->ops->conf_tx(local_to_hw(local), i, &qparam);
615 }
616
617 void ieee80211_tx_skb(struct ieee80211_sub_if_data *sdata, struct sk_buff *skb,
618                       int encrypt)
619 {
620         skb->dev = sdata->local->mdev;
621         skb_set_mac_header(skb, 0);
622         skb_set_network_header(skb, 0);
623         skb_set_transport_header(skb, 0);
624
625         skb->iif = sdata->dev->ifindex;
626         skb->do_not_encrypt = !encrypt;
627
628         dev_queue_xmit(skb);
629 }
630
631 int ieee80211_set_freq(struct ieee80211_sub_if_data *sdata, int freqMHz)
632 {
633         int ret = -EINVAL;
634         struct ieee80211_channel *chan;
635         struct ieee80211_local *local = sdata->local;
636
637         chan = ieee80211_get_channel(local->hw.wiphy, freqMHz);
638
639         if (chan && !(chan->flags & IEEE80211_CHAN_DISABLED)) {
640                 if (sdata->vif.type == NL80211_IFTYPE_ADHOC &&
641                     chan->flags & IEEE80211_CHAN_NO_IBSS)
642                         return ret;
643                 local->oper_channel = chan;
644
645                 if (local->sw_scanning || local->hw_scanning)
646                         ret = 0;
647                 else
648                         ret = ieee80211_hw_config(local);
649
650                 rate_control_clear(local);
651         }
652
653         return ret;
654 }
655
656 u64 ieee80211_mandatory_rates(struct ieee80211_local *local,
657                               enum ieee80211_band band)
658 {
659         struct ieee80211_supported_band *sband;
660         struct ieee80211_rate *bitrates;
661         u64 mandatory_rates;
662         enum ieee80211_rate_flags mandatory_flag;
663         int i;
664
665         sband = local->hw.wiphy->bands[band];
666         if (!sband) {
667                 WARN_ON(1);
668                 sband = local->hw.wiphy->bands[local->hw.conf.channel->band];
669         }
670
671         if (band == IEEE80211_BAND_2GHZ)
672                 mandatory_flag = IEEE80211_RATE_MANDATORY_B;
673         else
674                 mandatory_flag = IEEE80211_RATE_MANDATORY_A;
675
676         bitrates = sband->bitrates;
677         mandatory_rates = 0;
678         for (i = 0; i < sband->n_bitrates; i++)
679                 if (bitrates[i].flags & mandatory_flag)
680                         mandatory_rates |= BIT(i);
681         return mandatory_rates;
682 }