mac80211: use nl80211 interface types
[linux-2.6] / 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 = vif_to_sdata(vif);
235         u16 dur;
236         int erp;
237
238         erp = 0;
239         if (sdata->flags & IEEE80211_SDATA_OPERATING_GMODE)
240                 erp = rate->flags & IEEE80211_RATE_ERP_G;
241
242         dur = ieee80211_frame_duration(local, frame_len, rate->bitrate, erp,
243                                        sdata->bss_conf.use_short_preamble);
244
245         return cpu_to_le16(dur);
246 }
247 EXPORT_SYMBOL(ieee80211_generic_frame_duration);
248
249 __le16 ieee80211_rts_duration(struct ieee80211_hw *hw,
250                               struct ieee80211_vif *vif, size_t frame_len,
251                               const struct ieee80211_tx_info *frame_txctl)
252 {
253         struct ieee80211_local *local = hw_to_local(hw);
254         struct ieee80211_rate *rate;
255         struct ieee80211_sub_if_data *sdata = vif_to_sdata(vif);
256         bool short_preamble;
257         int erp;
258         u16 dur;
259         struct ieee80211_supported_band *sband;
260
261         sband = local->hw.wiphy->bands[local->hw.conf.channel->band];
262
263         short_preamble = sdata->bss_conf.use_short_preamble;
264
265         rate = &sband->bitrates[frame_txctl->control.rts_cts_rate_idx];
266
267         erp = 0;
268         if (sdata->flags & IEEE80211_SDATA_OPERATING_GMODE)
269                 erp = rate->flags & IEEE80211_RATE_ERP_G;
270
271         /* CTS duration */
272         dur = ieee80211_frame_duration(local, 10, rate->bitrate,
273                                        erp, short_preamble);
274         /* Data frame duration */
275         dur += ieee80211_frame_duration(local, frame_len, rate->bitrate,
276                                         erp, short_preamble);
277         /* ACK duration */
278         dur += ieee80211_frame_duration(local, 10, rate->bitrate,
279                                         erp, short_preamble);
280
281         return cpu_to_le16(dur);
282 }
283 EXPORT_SYMBOL(ieee80211_rts_duration);
284
285 __le16 ieee80211_ctstoself_duration(struct ieee80211_hw *hw,
286                                     struct ieee80211_vif *vif,
287                                     size_t frame_len,
288                                     const struct ieee80211_tx_info *frame_txctl)
289 {
290         struct ieee80211_local *local = hw_to_local(hw);
291         struct ieee80211_rate *rate;
292         struct ieee80211_sub_if_data *sdata = vif_to_sdata(vif);
293         bool short_preamble;
294         int erp;
295         u16 dur;
296         struct ieee80211_supported_band *sband;
297
298         sband = local->hw.wiphy->bands[local->hw.conf.channel->band];
299
300         short_preamble = sdata->bss_conf.use_short_preamble;
301
302         rate = &sband->bitrates[frame_txctl->control.rts_cts_rate_idx];
303         erp = 0;
304         if (sdata->flags & IEEE80211_SDATA_OPERATING_GMODE)
305                 erp = rate->flags & IEEE80211_RATE_ERP_G;
306
307         /* Data frame duration */
308         dur = ieee80211_frame_duration(local, frame_len, rate->bitrate,
309                                        erp, short_preamble);
310         if (!(frame_txctl->flags & IEEE80211_TX_CTL_NO_ACK)) {
311                 /* ACK duration */
312                 dur += ieee80211_frame_duration(local, 10, rate->bitrate,
313                                                 erp, short_preamble);
314         }
315
316         return cpu_to_le16(dur);
317 }
318 EXPORT_SYMBOL(ieee80211_ctstoself_duration);
319
320 void ieee80211_wake_queue(struct ieee80211_hw *hw, int queue)
321 {
322         struct ieee80211_local *local = hw_to_local(hw);
323
324         if (test_bit(queue, local->queues_pending)) {
325                 set_bit(queue, local->queues_pending_run);
326                 tasklet_schedule(&local->tx_pending_tasklet);
327         } else {
328                 netif_wake_subqueue(local->mdev, queue);
329         }
330 }
331 EXPORT_SYMBOL(ieee80211_wake_queue);
332
333 void ieee80211_stop_queue(struct ieee80211_hw *hw, int queue)
334 {
335         struct ieee80211_local *local = hw_to_local(hw);
336
337         netif_stop_subqueue(local->mdev, queue);
338 }
339 EXPORT_SYMBOL(ieee80211_stop_queue);
340
341 void ieee80211_stop_queues(struct ieee80211_hw *hw)
342 {
343         int i;
344
345         for (i = 0; i < ieee80211_num_queues(hw); i++)
346                 ieee80211_stop_queue(hw, i);
347 }
348 EXPORT_SYMBOL(ieee80211_stop_queues);
349
350 int ieee80211_queue_stopped(struct ieee80211_hw *hw, int queue)
351 {
352         struct ieee80211_local *local = hw_to_local(hw);
353         return __netif_subqueue_stopped(local->mdev, queue);
354 }
355 EXPORT_SYMBOL(ieee80211_queue_stopped);
356
357 void ieee80211_wake_queues(struct ieee80211_hw *hw)
358 {
359         int i;
360
361         for (i = 0; i < hw->queues + hw->ampdu_queues; i++)
362                 ieee80211_wake_queue(hw, i);
363 }
364 EXPORT_SYMBOL(ieee80211_wake_queues);
365
366 void ieee80211_iterate_active_interfaces(
367         struct ieee80211_hw *hw,
368         void (*iterator)(void *data, u8 *mac,
369                          struct ieee80211_vif *vif),
370         void *data)
371 {
372         struct ieee80211_local *local = hw_to_local(hw);
373         struct ieee80211_sub_if_data *sdata;
374
375         rtnl_lock();
376
377         list_for_each_entry(sdata, &local->interfaces, list) {
378                 switch (sdata->vif.type) {
379                 case __NL80211_IFTYPE_AFTER_LAST:
380                 case NL80211_IFTYPE_UNSPECIFIED:
381                 case NL80211_IFTYPE_MONITOR:
382                 case NL80211_IFTYPE_AP_VLAN:
383                         continue;
384                 case NL80211_IFTYPE_AP:
385                 case NL80211_IFTYPE_STATION:
386                 case NL80211_IFTYPE_ADHOC:
387                 case NL80211_IFTYPE_WDS:
388                 case NL80211_IFTYPE_MESH_POINT:
389                         break;
390                 }
391                 if (netif_running(sdata->dev))
392                         iterator(data, sdata->dev->dev_addr,
393                                  &sdata->vif);
394         }
395
396         rtnl_unlock();
397 }
398 EXPORT_SYMBOL_GPL(ieee80211_iterate_active_interfaces);
399
400 void ieee80211_iterate_active_interfaces_atomic(
401         struct ieee80211_hw *hw,
402         void (*iterator)(void *data, u8 *mac,
403                          struct ieee80211_vif *vif),
404         void *data)
405 {
406         struct ieee80211_local *local = hw_to_local(hw);
407         struct ieee80211_sub_if_data *sdata;
408
409         rcu_read_lock();
410
411         list_for_each_entry_rcu(sdata, &local->interfaces, list) {
412                 switch (sdata->vif.type) {
413                 case __NL80211_IFTYPE_AFTER_LAST:
414                 case NL80211_IFTYPE_UNSPECIFIED:
415                 case NL80211_IFTYPE_MONITOR:
416                 case NL80211_IFTYPE_AP_VLAN:
417                         continue;
418                 case NL80211_IFTYPE_AP:
419                 case NL80211_IFTYPE_STATION:
420                 case NL80211_IFTYPE_ADHOC:
421                 case NL80211_IFTYPE_WDS:
422                 case NL80211_IFTYPE_MESH_POINT:
423                         break;
424                 }
425                 if (netif_running(sdata->dev))
426                         iterator(data, sdata->dev->dev_addr,
427                                  &sdata->vif);
428         }
429
430         rcu_read_unlock();
431 }
432 EXPORT_SYMBOL_GPL(ieee80211_iterate_active_interfaces_atomic);
433
434 void ieee802_11_parse_elems(u8 *start, size_t len,
435                             struct ieee802_11_elems *elems)
436 {
437         size_t left = len;
438         u8 *pos = start;
439
440         memset(elems, 0, sizeof(*elems));
441         elems->ie_start = start;
442         elems->total_len = len;
443
444         while (left >= 2) {
445                 u8 id, elen;
446
447                 id = *pos++;
448                 elen = *pos++;
449                 left -= 2;
450
451                 if (elen > left)
452                         return;
453
454                 switch (id) {
455                 case WLAN_EID_SSID:
456                         elems->ssid = pos;
457                         elems->ssid_len = elen;
458                         break;
459                 case WLAN_EID_SUPP_RATES:
460                         elems->supp_rates = pos;
461                         elems->supp_rates_len = elen;
462                         break;
463                 case WLAN_EID_FH_PARAMS:
464                         elems->fh_params = pos;
465                         elems->fh_params_len = elen;
466                         break;
467                 case WLAN_EID_DS_PARAMS:
468                         elems->ds_params = pos;
469                         elems->ds_params_len = elen;
470                         break;
471                 case WLAN_EID_CF_PARAMS:
472                         elems->cf_params = pos;
473                         elems->cf_params_len = elen;
474                         break;
475                 case WLAN_EID_TIM:
476                         elems->tim = pos;
477                         elems->tim_len = elen;
478                         break;
479                 case WLAN_EID_IBSS_PARAMS:
480                         elems->ibss_params = pos;
481                         elems->ibss_params_len = elen;
482                         break;
483                 case WLAN_EID_CHALLENGE:
484                         elems->challenge = pos;
485                         elems->challenge_len = elen;
486                         break;
487                 case WLAN_EID_WPA:
488                         if (elen >= 4 && pos[0] == 0x00 && pos[1] == 0x50 &&
489                             pos[2] == 0xf2) {
490                                 /* Microsoft OUI (00:50:F2) */
491                                 if (pos[3] == 1) {
492                                         /* OUI Type 1 - WPA IE */
493                                         elems->wpa = pos;
494                                         elems->wpa_len = elen;
495                                 } else if (elen >= 5 && pos[3] == 2) {
496                                         if (pos[4] == 0) {
497                                                 elems->wmm_info = pos;
498                                                 elems->wmm_info_len = elen;
499                                         } else if (pos[4] == 1) {
500                                                 elems->wmm_param = pos;
501                                                 elems->wmm_param_len = elen;
502                                         }
503                                 }
504                         }
505                         break;
506                 case WLAN_EID_RSN:
507                         elems->rsn = pos;
508                         elems->rsn_len = elen;
509                         break;
510                 case WLAN_EID_ERP_INFO:
511                         elems->erp_info = pos;
512                         elems->erp_info_len = elen;
513                         break;
514                 case WLAN_EID_EXT_SUPP_RATES:
515                         elems->ext_supp_rates = pos;
516                         elems->ext_supp_rates_len = elen;
517                         break;
518                 case WLAN_EID_HT_CAPABILITY:
519                         elems->ht_cap_elem = pos;
520                         elems->ht_cap_elem_len = elen;
521                         break;
522                 case WLAN_EID_HT_EXTRA_INFO:
523                         elems->ht_info_elem = pos;
524                         elems->ht_info_elem_len = elen;
525                         break;
526                 case WLAN_EID_MESH_ID:
527                         elems->mesh_id = pos;
528                         elems->mesh_id_len = elen;
529                         break;
530                 case WLAN_EID_MESH_CONFIG:
531                         elems->mesh_config = pos;
532                         elems->mesh_config_len = elen;
533                         break;
534                 case WLAN_EID_PEER_LINK:
535                         elems->peer_link = pos;
536                         elems->peer_link_len = elen;
537                         break;
538                 case WLAN_EID_PREQ:
539                         elems->preq = pos;
540                         elems->preq_len = elen;
541                         break;
542                 case WLAN_EID_PREP:
543                         elems->prep = pos;
544                         elems->prep_len = elen;
545                         break;
546                 case WLAN_EID_PERR:
547                         elems->perr = pos;
548                         elems->perr_len = elen;
549                         break;
550                 case WLAN_EID_CHANNEL_SWITCH:
551                         elems->ch_switch_elem = pos;
552                         elems->ch_switch_elem_len = elen;
553                         break;
554                 case WLAN_EID_QUIET:
555                         if (!elems->quiet_elem) {
556                                 elems->quiet_elem = pos;
557                                 elems->quiet_elem_len = elen;
558                         }
559                         elems->num_of_quiet_elem++;
560                         break;
561                 case WLAN_EID_COUNTRY:
562                         elems->country_elem = pos;
563                         elems->country_elem_len = elen;
564                         break;
565                 case WLAN_EID_PWR_CONSTRAINT:
566                         elems->pwr_constr_elem = pos;
567                         elems->pwr_constr_elem_len = elen;
568                         break;
569                 default:
570                         break;
571                 }
572
573                 left -= elen;
574                 pos += elen;
575         }
576 }
577
578 void ieee80211_set_wmm_default(struct ieee80211_sub_if_data *sdata)
579 {
580         struct ieee80211_local *local = sdata->local;
581         struct ieee80211_tx_queue_params qparam;
582         int i;
583
584         if (!local->ops->conf_tx)
585                 return;
586
587         memset(&qparam, 0, sizeof(qparam));
588
589         qparam.aifs = 2;
590
591         if (local->hw.conf.channel->band == IEEE80211_BAND_2GHZ &&
592             !(sdata->flags & IEEE80211_SDATA_OPERATING_GMODE))
593                 qparam.cw_min = 31;
594         else
595                 qparam.cw_min = 15;
596
597         qparam.cw_max = 1023;
598         qparam.txop = 0;
599
600         for (i = 0; i < local_to_hw(local)->queues; i++)
601                 local->ops->conf_tx(local_to_hw(local), i, &qparam);
602 }
603
604 void ieee80211_tx_skb(struct ieee80211_sub_if_data *sdata, struct sk_buff *skb,
605                       int encrypt)
606 {
607         skb->dev = sdata->local->mdev;
608         skb_set_mac_header(skb, 0);
609         skb_set_network_header(skb, 0);
610         skb_set_transport_header(skb, 0);
611
612         skb->iif = sdata->dev->ifindex;
613         skb->do_not_encrypt = !encrypt;
614
615         dev_queue_xmit(skb);
616 }
617
618 int ieee80211_set_freq(struct ieee80211_sub_if_data *sdata, int freqMHz)
619 {
620         int ret = -EINVAL;
621         struct ieee80211_channel *chan;
622         struct ieee80211_local *local = sdata->local;
623
624         chan = ieee80211_get_channel(local->hw.wiphy, freqMHz);
625
626         if (chan && !(chan->flags & IEEE80211_CHAN_DISABLED)) {
627                 if (sdata->vif.type == NL80211_IFTYPE_ADHOC &&
628                     chan->flags & IEEE80211_CHAN_NO_IBSS) {
629                         printk(KERN_DEBUG "%s: IBSS not allowed on frequency "
630                                 "%d MHz\n", sdata->dev->name, chan->center_freq);
631                         return ret;
632                 }
633                 local->oper_channel = chan;
634
635                 if (local->sw_scanning || local->hw_scanning)
636                         ret = 0;
637                 else
638                         ret = ieee80211_hw_config(local);
639
640                 rate_control_clear(local);
641         }
642
643         return ret;
644 }
645
646 u64 ieee80211_mandatory_rates(struct ieee80211_local *local,
647                               enum ieee80211_band band)
648 {
649         struct ieee80211_supported_band *sband;
650         struct ieee80211_rate *bitrates;
651         u64 mandatory_rates;
652         enum ieee80211_rate_flags mandatory_flag;
653         int i;
654
655         sband = local->hw.wiphy->bands[band];
656         if (!sband) {
657                 WARN_ON(1);
658                 sband = local->hw.wiphy->bands[local->hw.conf.channel->band];
659         }
660
661         if (band == IEEE80211_BAND_2GHZ)
662                 mandatory_flag = IEEE80211_RATE_MANDATORY_B;
663         else
664                 mandatory_flag = IEEE80211_RATE_MANDATORY_A;
665
666         bitrates = sband->bitrates;
667         mandatory_rates = 0;
668         for (i = 0; i < sband->n_bitrates; i++)
669                 if (bitrates[i].flags & mandatory_flag)
670                         mandatory_rates |= BIT(i);
671         return mandatory_rates;
672 }