439c98d93a79cedee816fa34e1fc7e5069d2e5f5
[linux-2.6.git] / net / mac80211 / scan.c
1 /*
2  * Scanning implementation
3  *
4  * Copyright 2003, Jouni Malinen <jkmaline@cc.hut.fi>
5  * Copyright 2004, Instant802 Networks, Inc.
6  * Copyright 2005, Devicescape Software, Inc.
7  * Copyright 2006-2007  Jiri Benc <jbenc@suse.cz>
8  * Copyright 2007, Michael Wu <flamingice@sourmilk.net>
9  *
10  * This program is free software; you can redistribute it and/or modify
11  * it under the terms of the GNU General Public License version 2 as
12  * published by the Free Software Foundation.
13  */
14
15 #include <linux/if_arp.h>
16 #include <linux/rtnetlink.h>
17 #include <linux/pm_qos_params.h>
18 #include <net/sch_generic.h>
19 #include <linux/slab.h>
20 #include <net/mac80211.h>
21
22 #include "ieee80211_i.h"
23 #include "driver-ops.h"
24 #include "mesh.h"
25
26 #define IEEE80211_PROBE_DELAY (HZ / 33)
27 #define IEEE80211_CHANNEL_TIME (HZ / 33)
28 #define IEEE80211_PASSIVE_CHANNEL_TIME (HZ / 8)
29
30 struct ieee80211_bss *
31 ieee80211_rx_bss_get(struct ieee80211_local *local, u8 *bssid, int freq,
32                      u8 *ssid, u8 ssid_len)
33 {
34         struct cfg80211_bss *cbss;
35
36         cbss = cfg80211_get_bss(local->hw.wiphy,
37                                 ieee80211_get_channel(local->hw.wiphy, freq),
38                                 bssid, ssid, ssid_len, 0, 0);
39         if (!cbss)
40                 return NULL;
41         return (void *)cbss->priv;
42 }
43
44 static void ieee80211_rx_bss_free(struct cfg80211_bss *cbss)
45 {
46         struct ieee80211_bss *bss = (void *)cbss->priv;
47
48         kfree(bss_mesh_id(bss));
49         kfree(bss_mesh_cfg(bss));
50 }
51
52 void ieee80211_rx_bss_put(struct ieee80211_local *local,
53                           struct ieee80211_bss *bss)
54 {
55         if (!bss)
56                 return;
57         cfg80211_put_bss(container_of((void *)bss, struct cfg80211_bss, priv));
58 }
59
60 static bool is_uapsd_supported(struct ieee802_11_elems *elems)
61 {
62         u8 qos_info;
63
64         if (elems->wmm_info && elems->wmm_info_len == 7
65             && elems->wmm_info[5] == 1)
66                 qos_info = elems->wmm_info[6];
67         else if (elems->wmm_param && elems->wmm_param_len == 24
68                  && elems->wmm_param[5] == 1)
69                 qos_info = elems->wmm_param[6];
70         else
71                 /* no valid wmm information or parameter element found */
72                 return false;
73
74         return qos_info & IEEE80211_WMM_IE_AP_QOSINFO_UAPSD;
75 }
76
77 struct ieee80211_bss *
78 ieee80211_bss_info_update(struct ieee80211_local *local,
79                           struct ieee80211_rx_status *rx_status,
80                           struct ieee80211_mgmt *mgmt,
81                           size_t len,
82                           struct ieee802_11_elems *elems,
83                           struct ieee80211_channel *channel,
84                           bool beacon)
85 {
86         struct cfg80211_bss *cbss;
87         struct ieee80211_bss *bss;
88         int clen, srlen;
89         s32 signal = 0;
90
91         if (local->hw.flags & IEEE80211_HW_SIGNAL_DBM)
92                 signal = rx_status->signal * 100;
93         else if (local->hw.flags & IEEE80211_HW_SIGNAL_UNSPEC)
94                 signal = (rx_status->signal * 100) / local->hw.max_signal;
95
96         cbss = cfg80211_inform_bss_frame(local->hw.wiphy, channel,
97                                          mgmt, len, signal, GFP_ATOMIC);
98
99         if (!cbss)
100                 return NULL;
101
102         cbss->free_priv = ieee80211_rx_bss_free;
103         bss = (void *)cbss->priv;
104
105         /* save the ERP value so that it is available at association time */
106         if (elems->erp_info && elems->erp_info_len >= 1) {
107                 bss->erp_value = elems->erp_info[0];
108                 bss->has_erp_value = 1;
109         }
110
111         if (elems->tim) {
112                 struct ieee80211_tim_ie *tim_ie =
113                         (struct ieee80211_tim_ie *)elems->tim;
114                 bss->dtim_period = tim_ie->dtim_period;
115         }
116
117         /* replace old supported rates if we get new values */
118         srlen = 0;
119         if (elems->supp_rates) {
120                 clen = IEEE80211_MAX_SUPP_RATES;
121                 if (clen > elems->supp_rates_len)
122                         clen = elems->supp_rates_len;
123                 memcpy(bss->supp_rates, elems->supp_rates, clen);
124                 srlen += clen;
125         }
126         if (elems->ext_supp_rates) {
127                 clen = IEEE80211_MAX_SUPP_RATES - srlen;
128                 if (clen > elems->ext_supp_rates_len)
129                         clen = elems->ext_supp_rates_len;
130                 memcpy(bss->supp_rates + srlen, elems->ext_supp_rates, clen);
131                 srlen += clen;
132         }
133         if (srlen)
134                 bss->supp_rates_len = srlen;
135
136         bss->wmm_used = elems->wmm_param || elems->wmm_info;
137         bss->uapsd_supported = is_uapsd_supported(elems);
138
139         if (!beacon)
140                 bss->last_probe_resp = jiffies;
141
142         return bss;
143 }
144
145 ieee80211_rx_result
146 ieee80211_scan_rx(struct ieee80211_sub_if_data *sdata, struct sk_buff *skb)
147 {
148         struct ieee80211_rx_status *rx_status = IEEE80211_SKB_RXCB(skb);
149         struct ieee80211_mgmt *mgmt;
150         struct ieee80211_bss *bss;
151         u8 *elements;
152         struct ieee80211_channel *channel;
153         size_t baselen;
154         int freq;
155         __le16 fc;
156         bool presp, beacon = false;
157         struct ieee802_11_elems elems;
158
159         if (skb->len < 2)
160                 return RX_DROP_UNUSABLE;
161
162         mgmt = (struct ieee80211_mgmt *) skb->data;
163         fc = mgmt->frame_control;
164
165         if (ieee80211_is_ctl(fc))
166                 return RX_CONTINUE;
167
168         if (skb->len < 24)
169                 return RX_DROP_MONITOR;
170
171         presp = ieee80211_is_probe_resp(fc);
172         if (presp) {
173                 /* ignore ProbeResp to foreign address */
174                 if (memcmp(mgmt->da, sdata->vif.addr, ETH_ALEN))
175                         return RX_DROP_MONITOR;
176
177                 presp = true;
178                 elements = mgmt->u.probe_resp.variable;
179                 baselen = offsetof(struct ieee80211_mgmt, u.probe_resp.variable);
180         } else {
181                 beacon = ieee80211_is_beacon(fc);
182                 baselen = offsetof(struct ieee80211_mgmt, u.beacon.variable);
183                 elements = mgmt->u.beacon.variable;
184         }
185
186         if (!presp && !beacon)
187                 return RX_CONTINUE;
188
189         if (baselen > skb->len)
190                 return RX_DROP_MONITOR;
191
192         ieee802_11_parse_elems(elements, skb->len - baselen, &elems);
193
194         if (elems.ds_params && elems.ds_params_len == 1)
195                 freq = ieee80211_channel_to_frequency(elems.ds_params[0]);
196         else
197                 freq = rx_status->freq;
198
199         channel = ieee80211_get_channel(sdata->local->hw.wiphy, freq);
200
201         if (!channel || channel->flags & IEEE80211_CHAN_DISABLED)
202                 return RX_DROP_MONITOR;
203
204         bss = ieee80211_bss_info_update(sdata->local, rx_status,
205                                         mgmt, skb->len, &elems,
206                                         channel, beacon);
207         if (bss)
208                 ieee80211_rx_bss_put(sdata->local, bss);
209
210         dev_kfree_skb(skb);
211         return RX_QUEUED;
212 }
213
214 /* return false if no more work */
215 static bool ieee80211_prep_hw_scan(struct ieee80211_local *local)
216 {
217         struct cfg80211_scan_request *req = local->scan_req;
218         enum ieee80211_band band;
219         int i, ielen, n_chans;
220
221         do {
222                 if (local->hw_scan_band == IEEE80211_NUM_BANDS)
223                         return false;
224
225                 band = local->hw_scan_band;
226                 n_chans = 0;
227                 for (i = 0; i < req->n_channels; i++) {
228                         if (req->channels[i]->band == band) {
229                                 local->hw_scan_req->channels[n_chans] =
230                                                         req->channels[i];
231                                 n_chans++;
232                         }
233                 }
234
235                 local->hw_scan_band++;
236         } while (!n_chans);
237
238         local->hw_scan_req->n_channels = n_chans;
239
240         ielen = ieee80211_build_preq_ies(local, (u8 *)local->hw_scan_req->ie,
241                                          req->ie, req->ie_len, band);
242         local->hw_scan_req->ie_len = ielen;
243
244         return true;
245 }
246
247 void ieee80211_scan_completed(struct ieee80211_hw *hw, bool aborted)
248 {
249         struct ieee80211_local *local = hw_to_local(hw);
250         bool was_hw_scan;
251
252         trace_api_scan_completed(local, aborted);
253
254         mutex_lock(&local->scan_mtx);
255
256         /*
257          * It's ok to abort a not-yet-running scan (that
258          * we have one at all will be verified by checking
259          * local->scan_req next), but not to complete it
260          * successfully.
261          */
262         if (WARN_ON(!local->scanning && !aborted))
263                 aborted = true;
264
265         if (WARN_ON(!local->scan_req)) {
266                 mutex_unlock(&local->scan_mtx);
267                 return;
268         }
269
270         was_hw_scan = test_bit(SCAN_HW_SCANNING, &local->scanning);
271         if (was_hw_scan && !aborted && ieee80211_prep_hw_scan(local)) {
272                 ieee80211_queue_delayed_work(&local->hw,
273                                              &local->scan_work, 0);
274                 mutex_unlock(&local->scan_mtx);
275                 return;
276         }
277
278         kfree(local->hw_scan_req);
279         local->hw_scan_req = NULL;
280
281         if (local->scan_req != local->int_scan_req)
282                 cfg80211_scan_done(local->scan_req, aborted);
283         local->scan_req = NULL;
284         local->scan_sdata = NULL;
285
286         local->scanning = 0;
287         local->scan_channel = NULL;
288
289         drv_sw_scan_complete(local);
290
291         /* we only have to protect scan_req and hw/sw scan */
292         mutex_unlock(&local->scan_mtx);
293
294         ieee80211_hw_config(local, IEEE80211_CONF_CHANGE_CHANNEL);
295         if (was_hw_scan)
296                 goto done;
297
298         ieee80211_configure_filter(local);
299
300         ieee80211_offchannel_return(local, true);
301
302  done:
303         ieee80211_recalc_idle(local);
304         ieee80211_mlme_notify_scan_completed(local);
305         ieee80211_ibss_notify_scan_completed(local);
306         ieee80211_mesh_notify_scan_completed(local);
307         ieee80211_queue_work(&local->hw, &local->work_work);
308 }
309 EXPORT_SYMBOL(ieee80211_scan_completed);
310
311 static int ieee80211_start_sw_scan(struct ieee80211_local *local)
312 {
313         /*
314          * Hardware/driver doesn't support hw_scan, so use software
315          * scanning instead. First send a nullfunc frame with power save
316          * bit on so that AP will buffer the frames for us while we are not
317          * listening, then send probe requests to each channel and wait for
318          * the responses. After all channels are scanned, tune back to the
319          * original channel and send a nullfunc frame with power save bit
320          * off to trigger the AP to send us all the buffered frames.
321          *
322          * Note that while local->sw_scanning is true everything else but
323          * nullfunc frames and probe requests will be dropped in
324          * ieee80211_tx_h_check_assoc().
325          */
326         drv_sw_scan_start(local);
327
328         ieee80211_offchannel_stop_beaconing(local);
329
330         local->leave_oper_channel_time = 0;
331         local->next_scan_state = SCAN_DECISION;
332         local->scan_channel_idx = 0;
333
334         drv_flush(local, false);
335
336         ieee80211_configure_filter(local);
337
338         ieee80211_queue_delayed_work(&local->hw,
339                                      &local->scan_work,
340                                      IEEE80211_CHANNEL_TIME);
341
342         return 0;
343 }
344
345
346 static int __ieee80211_start_scan(struct ieee80211_sub_if_data *sdata,
347                                   struct cfg80211_scan_request *req)
348 {
349         struct ieee80211_local *local = sdata->local;
350         int rc;
351
352         if (local->scan_req)
353                 return -EBUSY;
354
355         if (!list_empty(&local->work_list)) {
356                 /* wait for the work to finish/time out */
357                 local->scan_req = req;
358                 local->scan_sdata = sdata;
359                 return 0;
360         }
361
362         if (local->ops->hw_scan) {
363                 u8 *ies;
364
365                 local->hw_scan_req = kmalloc(
366                                 sizeof(*local->hw_scan_req) +
367                                 req->n_channels * sizeof(req->channels[0]) +
368                                 2 + IEEE80211_MAX_SSID_LEN + local->scan_ies_len +
369                                 req->ie_len, GFP_KERNEL);
370                 if (!local->hw_scan_req)
371                         return -ENOMEM;
372
373                 local->hw_scan_req->ssids = req->ssids;
374                 local->hw_scan_req->n_ssids = req->n_ssids;
375                 ies = (u8 *)local->hw_scan_req +
376                         sizeof(*local->hw_scan_req) +
377                         req->n_channels * sizeof(req->channels[0]);
378                 local->hw_scan_req->ie = ies;
379
380                 local->hw_scan_band = 0;
381
382                 /*
383                  * After allocating local->hw_scan_req, we must
384                  * go through until ieee80211_prep_hw_scan(), so
385                  * anything that might be changed here and leave
386                  * this function early must not go after this
387                  * allocation.
388                  */
389         }
390
391         local->scan_req = req;
392         local->scan_sdata = sdata;
393
394         if (local->ops->hw_scan)
395                 __set_bit(SCAN_HW_SCANNING, &local->scanning);
396         else
397                 __set_bit(SCAN_SW_SCANNING, &local->scanning);
398
399         /*
400          * Kicking off the scan need not be protected,
401          * only the scan variable stuff, since now
402          * local->scan_req is assigned and other callers
403          * will abort their scan attempts.
404          *
405          * This avoids too many locking dependencies
406          * so that the scan completed calls have more
407          * locking freedom.
408          */
409
410         ieee80211_recalc_idle(local);
411         mutex_unlock(&local->scan_mtx);
412
413         if (local->ops->hw_scan) {
414                 WARN_ON(!ieee80211_prep_hw_scan(local));
415                 rc = drv_hw_scan(local, sdata, local->hw_scan_req);
416         } else
417                 rc = ieee80211_start_sw_scan(local);
418
419         mutex_lock(&local->scan_mtx);
420
421         if (rc) {
422                 kfree(local->hw_scan_req);
423                 local->hw_scan_req = NULL;
424                 local->scanning = 0;
425
426                 ieee80211_recalc_idle(local);
427
428                 local->scan_req = NULL;
429                 local->scan_sdata = NULL;
430         }
431
432         return rc;
433 }
434
435 static unsigned long
436 ieee80211_scan_get_channel_time(struct ieee80211_channel *chan)
437 {
438         /*
439          * TODO: channel switching also consumes quite some time,
440          * add that delay as well to get a better estimation
441          */
442         if (chan->flags & IEEE80211_CHAN_PASSIVE_SCAN)
443                 return IEEE80211_PASSIVE_CHANNEL_TIME;
444         return IEEE80211_PROBE_DELAY + IEEE80211_CHANNEL_TIME;
445 }
446
447 static int ieee80211_scan_state_decision(struct ieee80211_local *local,
448                                          unsigned long *next_delay)
449 {
450         bool associated = false;
451         bool tx_empty = true;
452         bool bad_latency;
453         bool listen_int_exceeded;
454         unsigned long min_beacon_int = 0;
455         struct ieee80211_sub_if_data *sdata;
456         struct ieee80211_channel *next_chan;
457
458         /* if no more bands/channels left, complete scan and advance to the idle state */
459         if (local->scan_channel_idx >= local->scan_req->n_channels) {
460                 ieee80211_scan_completed(&local->hw, false);
461                 return 1;
462         }
463
464         /*
465          * check if at least one STA interface is associated,
466          * check if at least one STA interface has pending tx frames
467          * and grab the lowest used beacon interval
468          */
469         mutex_lock(&local->iflist_mtx);
470         list_for_each_entry(sdata, &local->interfaces, list) {
471                 if (!ieee80211_sdata_running(sdata))
472                         continue;
473
474                 if (sdata->vif.type == NL80211_IFTYPE_STATION) {
475                         if (sdata->u.mgd.associated) {
476                                 associated = true;
477
478                                 if (sdata->vif.bss_conf.beacon_int <
479                                     min_beacon_int || min_beacon_int == 0)
480                                         min_beacon_int =
481                                                 sdata->vif.bss_conf.beacon_int;
482
483                                 if (!qdisc_all_tx_empty(sdata->dev)) {
484                                         tx_empty = false;
485                                         break;
486                                 }
487                         }
488                 }
489         }
490         mutex_unlock(&local->iflist_mtx);
491
492         if (local->scan_channel) {
493                 /*
494                  * we're currently scanning a different channel, let's
495                  * see if we can scan another channel without interfering
496                  * with the current traffic situation.
497                  *
498                  * Since we don't know if the AP has pending frames for us
499                  * we can only check for our tx queues and use the current
500                  * pm_qos requirements for rx. Hence, if no tx traffic occurs
501                  * at all we will scan as many channels in a row as the pm_qos
502                  * latency allows us to. Additionally we also check for the
503                  * currently negotiated listen interval to prevent losing
504                  * frames unnecessarily.
505                  *
506                  * Otherwise switch back to the operating channel.
507                  */
508                 next_chan = local->scan_req->channels[local->scan_channel_idx];
509
510                 bad_latency = time_after(jiffies +
511                                 ieee80211_scan_get_channel_time(next_chan),
512                                 local->leave_oper_channel_time +
513                                 usecs_to_jiffies(pm_qos_request(PM_QOS_NETWORK_LATENCY)));
514
515                 listen_int_exceeded = time_after(jiffies +
516                                 ieee80211_scan_get_channel_time(next_chan),
517                                 local->leave_oper_channel_time +
518                                 usecs_to_jiffies(min_beacon_int * 1024) *
519                                 local->hw.conf.listen_interval);
520
521                 if (associated && ( !tx_empty || bad_latency ||
522                     listen_int_exceeded))
523                         local->next_scan_state = SCAN_ENTER_OPER_CHANNEL;
524                 else
525                         local->next_scan_state = SCAN_SET_CHANNEL;
526         } else {
527                 /*
528                  * we're on the operating channel currently, let's
529                  * leave that channel now to scan another one
530                  */
531                 local->next_scan_state = SCAN_LEAVE_OPER_CHANNEL;
532         }
533
534         *next_delay = 0;
535         return 0;
536 }
537
538 static void ieee80211_scan_state_leave_oper_channel(struct ieee80211_local *local,
539                                                     unsigned long *next_delay)
540 {
541         ieee80211_offchannel_stop_station(local);
542
543         __set_bit(SCAN_OFF_CHANNEL, &local->scanning);
544
545         /*
546          * What if the nullfunc frames didn't arrive?
547          */
548         drv_flush(local, false);
549         if (local->ops->flush)
550                 *next_delay = 0;
551         else
552                 *next_delay = HZ / 10;
553
554         /* remember when we left the operating channel */
555         local->leave_oper_channel_time = jiffies;
556
557         /* advance to the next channel to be scanned */
558         local->next_scan_state = SCAN_SET_CHANNEL;
559 }
560
561 static void ieee80211_scan_state_enter_oper_channel(struct ieee80211_local *local,
562                                                     unsigned long *next_delay)
563 {
564         /* switch back to the operating channel */
565         local->scan_channel = NULL;
566         ieee80211_hw_config(local, IEEE80211_CONF_CHANGE_CHANNEL);
567
568         /*
569          * Only re-enable station mode interface now; beaconing will be
570          * re-enabled once the full scan has been completed.
571          */
572         ieee80211_offchannel_return(local, false);
573
574         __clear_bit(SCAN_OFF_CHANNEL, &local->scanning);
575
576         *next_delay = HZ / 5;
577         local->next_scan_state = SCAN_DECISION;
578 }
579
580 static void ieee80211_scan_state_set_channel(struct ieee80211_local *local,
581                                              unsigned long *next_delay)
582 {
583         int skip;
584         struct ieee80211_channel *chan;
585
586         skip = 0;
587         chan = local->scan_req->channels[local->scan_channel_idx];
588
589         local->scan_channel = chan;
590         if (ieee80211_hw_config(local, IEEE80211_CONF_CHANGE_CHANNEL))
591                 skip = 1;
592
593         /* advance state machine to next channel/band */
594         local->scan_channel_idx++;
595
596         if (skip) {
597                 /* if we skip this channel return to the decision state */
598                 local->next_scan_state = SCAN_DECISION;
599                 return;
600         }
601
602         /*
603          * Probe delay is used to update the NAV, cf. 11.1.3.2.2
604          * (which unfortunately doesn't say _why_ step a) is done,
605          * but it waits for the probe delay or until a frame is
606          * received - and the received frame would update the NAV).
607          * For now, we do not support waiting until a frame is
608          * received.
609          *
610          * In any case, it is not necessary for a passive scan.
611          */
612         if (chan->flags & IEEE80211_CHAN_PASSIVE_SCAN ||
613             !local->scan_req->n_ssids) {
614                 *next_delay = IEEE80211_PASSIVE_CHANNEL_TIME;
615                 local->next_scan_state = SCAN_DECISION;
616                 return;
617         }
618
619         /* active scan, send probes */
620         *next_delay = IEEE80211_PROBE_DELAY;
621         local->next_scan_state = SCAN_SEND_PROBE;
622 }
623
624 static void ieee80211_scan_state_send_probe(struct ieee80211_local *local,
625                                             unsigned long *next_delay)
626 {
627         int i;
628         struct ieee80211_sub_if_data *sdata = local->scan_sdata;
629
630         for (i = 0; i < local->scan_req->n_ssids; i++)
631                 ieee80211_send_probe_req(
632                         sdata, NULL,
633                         local->scan_req->ssids[i].ssid,
634                         local->scan_req->ssids[i].ssid_len,
635                         local->scan_req->ie, local->scan_req->ie_len);
636
637         /*
638          * After sending probe requests, wait for probe responses
639          * on the channel.
640          */
641         *next_delay = IEEE80211_CHANNEL_TIME;
642         local->next_scan_state = SCAN_DECISION;
643 }
644
645 void ieee80211_scan_work(struct work_struct *work)
646 {
647         struct ieee80211_local *local =
648                 container_of(work, struct ieee80211_local, scan_work.work);
649         struct ieee80211_sub_if_data *sdata = local->scan_sdata;
650         unsigned long next_delay = 0;
651
652         mutex_lock(&local->scan_mtx);
653         if (!sdata || !local->scan_req) {
654                 mutex_unlock(&local->scan_mtx);
655                 return;
656         }
657
658         if (local->hw_scan_req) {
659                 int rc = drv_hw_scan(local, sdata, local->hw_scan_req);
660                 mutex_unlock(&local->scan_mtx);
661                 if (rc)
662                         ieee80211_scan_completed(&local->hw, true);
663                 return;
664         }
665
666         if (local->scan_req && !local->scanning) {
667                 struct cfg80211_scan_request *req = local->scan_req;
668                 int rc;
669
670                 local->scan_req = NULL;
671                 local->scan_sdata = NULL;
672
673                 rc = __ieee80211_start_scan(sdata, req);
674                 mutex_unlock(&local->scan_mtx);
675
676                 if (rc)
677                         ieee80211_scan_completed(&local->hw, true);
678                 return;
679         }
680
681         mutex_unlock(&local->scan_mtx);
682
683         /*
684          * Avoid re-scheduling when the sdata is going away.
685          */
686         if (!ieee80211_sdata_running(sdata)) {
687                 ieee80211_scan_completed(&local->hw, true);
688                 return;
689         }
690
691         /*
692          * as long as no delay is required advance immediately
693          * without scheduling a new work
694          */
695         do {
696                 switch (local->next_scan_state) {
697                 case SCAN_DECISION:
698                         if (ieee80211_scan_state_decision(local, &next_delay))
699                                 return;
700                         break;
701                 case SCAN_SET_CHANNEL:
702                         ieee80211_scan_state_set_channel(local, &next_delay);
703                         break;
704                 case SCAN_SEND_PROBE:
705                         ieee80211_scan_state_send_probe(local, &next_delay);
706                         break;
707                 case SCAN_LEAVE_OPER_CHANNEL:
708                         ieee80211_scan_state_leave_oper_channel(local, &next_delay);
709                         break;
710                 case SCAN_ENTER_OPER_CHANNEL:
711                         ieee80211_scan_state_enter_oper_channel(local, &next_delay);
712                         break;
713                 }
714         } while (next_delay == 0);
715
716         ieee80211_queue_delayed_work(&local->hw, &local->scan_work, next_delay);
717 }
718
719 int ieee80211_request_scan(struct ieee80211_sub_if_data *sdata,
720                            struct cfg80211_scan_request *req)
721 {
722         int res;
723
724         mutex_lock(&sdata->local->scan_mtx);
725         res = __ieee80211_start_scan(sdata, req);
726         mutex_unlock(&sdata->local->scan_mtx);
727
728         return res;
729 }
730
731 int ieee80211_request_internal_scan(struct ieee80211_sub_if_data *sdata,
732                                     const u8 *ssid, u8 ssid_len,
733                                     struct ieee80211_channel *chan)
734 {
735         struct ieee80211_local *local = sdata->local;
736         int ret = -EBUSY;
737         enum ieee80211_band band;
738
739         mutex_lock(&local->scan_mtx);
740
741         /* busy scanning */
742         if (local->scan_req)
743                 goto unlock;
744
745         /* fill internal scan request */
746         if (!chan) {
747                 int i, nchan = 0;
748
749                 for (band = 0; band < IEEE80211_NUM_BANDS; band++) {
750                         if (!local->hw.wiphy->bands[band])
751                                 continue;
752                         for (i = 0;
753                              i < local->hw.wiphy->bands[band]->n_channels;
754                              i++) {
755                                 local->int_scan_req->channels[nchan] =
756                                     &local->hw.wiphy->bands[band]->channels[i];
757                                 nchan++;
758                         }
759                 }
760
761                 local->int_scan_req->n_channels = nchan;
762         } else {
763                 local->int_scan_req->channels[0] = chan;
764                 local->int_scan_req->n_channels = 1;
765         }
766
767         local->int_scan_req->ssids = &local->scan_ssid;
768         local->int_scan_req->n_ssids = 1;
769         memcpy(local->int_scan_req->ssids[0].ssid, ssid, IEEE80211_MAX_SSID_LEN);
770         local->int_scan_req->ssids[0].ssid_len = ssid_len;
771
772         ret = __ieee80211_start_scan(sdata, sdata->local->int_scan_req);
773  unlock:
774         mutex_unlock(&local->scan_mtx);
775         return ret;
776 }
777
778 void ieee80211_scan_cancel(struct ieee80211_local *local)
779 {
780         bool abortscan;
781
782         cancel_delayed_work_sync(&local->scan_work);
783
784         /*
785          * Only call this function when a scan can't be
786          * queued -- mostly at suspend under RTNL.
787          */
788         mutex_lock(&local->scan_mtx);
789         abortscan = test_bit(SCAN_SW_SCANNING, &local->scanning) ||
790                     (!local->scanning && local->scan_req);
791         mutex_unlock(&local->scan_mtx);
792
793         if (abortscan)
794                 ieee80211_scan_completed(&local->hw, true);
795 }