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