mac80211: assure we also cancel deferred scan request
[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         /* If the beacon had no TIM IE, or it was invalid, use 1 */
118         if (beacon && !bss->dtim_period)
119                 bss->dtim_period = 1;
120
121         /* replace old supported rates if we get new values */
122         srlen = 0;
123         if (elems->supp_rates) {
124                 clen = IEEE80211_MAX_SUPP_RATES;
125                 if (clen > elems->supp_rates_len)
126                         clen = elems->supp_rates_len;
127                 memcpy(bss->supp_rates, elems->supp_rates, clen);
128                 srlen += clen;
129         }
130         if (elems->ext_supp_rates) {
131                 clen = IEEE80211_MAX_SUPP_RATES - srlen;
132                 if (clen > elems->ext_supp_rates_len)
133                         clen = elems->ext_supp_rates_len;
134                 memcpy(bss->supp_rates + srlen, elems->ext_supp_rates, clen);
135                 srlen += clen;
136         }
137         if (srlen)
138                 bss->supp_rates_len = srlen;
139
140         bss->wmm_used = elems->wmm_param || elems->wmm_info;
141         bss->uapsd_supported = is_uapsd_supported(elems);
142
143         if (!beacon)
144                 bss->last_probe_resp = jiffies;
145
146         return bss;
147 }
148
149 ieee80211_rx_result
150 ieee80211_scan_rx(struct ieee80211_sub_if_data *sdata, struct sk_buff *skb)
151 {
152         struct ieee80211_rx_status *rx_status = IEEE80211_SKB_RXCB(skb);
153         struct ieee80211_mgmt *mgmt;
154         struct ieee80211_bss *bss;
155         u8 *elements;
156         struct ieee80211_channel *channel;
157         size_t baselen;
158         int freq;
159         __le16 fc;
160         bool presp, beacon = false;
161         struct ieee802_11_elems elems;
162
163         if (skb->len < 2)
164                 return RX_DROP_UNUSABLE;
165
166         mgmt = (struct ieee80211_mgmt *) skb->data;
167         fc = mgmt->frame_control;
168
169         if (ieee80211_is_ctl(fc))
170                 return RX_CONTINUE;
171
172         if (skb->len < 24)
173                 return RX_DROP_MONITOR;
174
175         presp = ieee80211_is_probe_resp(fc);
176         if (presp) {
177                 /* ignore ProbeResp to foreign address */
178                 if (memcmp(mgmt->da, sdata->vif.addr, ETH_ALEN))
179                         return RX_DROP_MONITOR;
180
181                 presp = true;
182                 elements = mgmt->u.probe_resp.variable;
183                 baselen = offsetof(struct ieee80211_mgmt, u.probe_resp.variable);
184         } else {
185                 beacon = ieee80211_is_beacon(fc);
186                 baselen = offsetof(struct ieee80211_mgmt, u.beacon.variable);
187                 elements = mgmt->u.beacon.variable;
188         }
189
190         if (!presp && !beacon)
191                 return RX_CONTINUE;
192
193         if (baselen > skb->len)
194                 return RX_DROP_MONITOR;
195
196         ieee802_11_parse_elems(elements, skb->len - baselen, &elems);
197
198         if (elems.ds_params && elems.ds_params_len == 1)
199                 freq = ieee80211_channel_to_frequency(elems.ds_params[0]);
200         else
201                 freq = rx_status->freq;
202
203         channel = ieee80211_get_channel(sdata->local->hw.wiphy, freq);
204
205         if (!channel || channel->flags & IEEE80211_CHAN_DISABLED)
206                 return RX_DROP_MONITOR;
207
208         bss = ieee80211_bss_info_update(sdata->local, rx_status,
209                                         mgmt, skb->len, &elems,
210                                         channel, beacon);
211         if (bss)
212                 ieee80211_rx_bss_put(sdata->local, bss);
213
214         dev_kfree_skb(skb);
215         return RX_QUEUED;
216 }
217
218 /* return false if no more work */
219 static bool ieee80211_prep_hw_scan(struct ieee80211_local *local)
220 {
221         struct cfg80211_scan_request *req = local->scan_req;
222         enum ieee80211_band band;
223         int i, ielen, n_chans;
224
225         do {
226                 if (local->hw_scan_band == IEEE80211_NUM_BANDS)
227                         return false;
228
229                 band = local->hw_scan_band;
230                 n_chans = 0;
231                 for (i = 0; i < req->n_channels; i++) {
232                         if (req->channels[i]->band == band) {
233                                 local->hw_scan_req->channels[n_chans] =
234                                                         req->channels[i];
235                                 n_chans++;
236                         }
237                 }
238
239                 local->hw_scan_band++;
240         } while (!n_chans);
241
242         local->hw_scan_req->n_channels = n_chans;
243
244         ielen = ieee80211_build_preq_ies(local, (u8 *)local->hw_scan_req->ie,
245                                          req->ie, req->ie_len, band, (u32) -1,
246                                          0);
247         local->hw_scan_req->ie_len = ielen;
248
249         return true;
250 }
251
252 static bool __ieee80211_scan_completed(struct ieee80211_hw *hw, bool aborted,
253                                        bool was_hw_scan)
254 {
255         struct ieee80211_local *local = hw_to_local(hw);
256
257         lockdep_assert_held(&local->mtx);
258
259         /*
260          * It's ok to abort a not-yet-running scan (that
261          * we have one at all will be verified by checking
262          * local->scan_req next), but not to complete it
263          * successfully.
264          */
265         if (WARN_ON(!local->scanning && !aborted))
266                 aborted = true;
267
268         if (WARN_ON(!local->scan_req))
269                 return false;
270
271         if (was_hw_scan && !aborted && ieee80211_prep_hw_scan(local)) {
272                 ieee80211_queue_delayed_work(&local->hw,
273                                              &local->scan_work, 0);
274                 return false;
275         }
276
277         kfree(local->hw_scan_req);
278         local->hw_scan_req = NULL;
279
280         if (local->scan_req != local->int_scan_req)
281                 cfg80211_scan_done(local->scan_req, aborted);
282         local->scan_req = NULL;
283         local->scan_sdata = NULL;
284
285         local->scanning = 0;
286         local->scan_channel = NULL;
287
288         return true;
289 }
290
291 static void __ieee80211_scan_completed_finish(struct ieee80211_hw *hw,
292                                               bool was_hw_scan)
293 {
294         struct ieee80211_local *local = hw_to_local(hw);
295
296         ieee80211_hw_config(local, IEEE80211_CONF_CHANGE_CHANNEL);
297         if (!was_hw_scan) {
298                 ieee80211_configure_filter(local);
299                 drv_sw_scan_complete(local);
300                 ieee80211_offchannel_return(local, true);
301         }
302
303         mutex_lock(&local->mtx);
304         ieee80211_recalc_idle(local);
305         mutex_unlock(&local->mtx);
306
307         ieee80211_mlme_notify_scan_completed(local);
308         ieee80211_ibss_notify_scan_completed(local);
309         ieee80211_mesh_notify_scan_completed(local);
310         ieee80211_queue_work(&local->hw, &local->work_work);
311 }
312
313 void ieee80211_scan_completed(struct ieee80211_hw *hw, bool aborted)
314 {
315         struct ieee80211_local *local = hw_to_local(hw);
316
317         trace_api_scan_completed(local, aborted);
318
319         set_bit(SCAN_COMPLETED, &local->scanning);
320         if (aborted)
321                 set_bit(SCAN_ABORTED, &local->scanning);
322         ieee80211_queue_delayed_work(&local->hw, &local->scan_work, 0);
323 }
324 EXPORT_SYMBOL(ieee80211_scan_completed);
325
326 static int ieee80211_start_sw_scan(struct ieee80211_local *local)
327 {
328         /*
329          * Hardware/driver doesn't support hw_scan, so use software
330          * scanning instead. First send a nullfunc frame with power save
331          * bit on so that AP will buffer the frames for us while we are not
332          * listening, then send probe requests to each channel and wait for
333          * the responses. After all channels are scanned, tune back to the
334          * original channel and send a nullfunc frame with power save bit
335          * off to trigger the AP to send us all the buffered frames.
336          *
337          * Note that while local->sw_scanning is true everything else but
338          * nullfunc frames and probe requests will be dropped in
339          * ieee80211_tx_h_check_assoc().
340          */
341         drv_sw_scan_start(local);
342
343         ieee80211_offchannel_stop_beaconing(local);
344
345         local->leave_oper_channel_time = 0;
346         local->next_scan_state = SCAN_DECISION;
347         local->scan_channel_idx = 0;
348
349         drv_flush(local, false);
350
351         ieee80211_configure_filter(local);
352
353         ieee80211_queue_delayed_work(&local->hw,
354                                      &local->scan_work,
355                                      IEEE80211_CHANNEL_TIME);
356
357         return 0;
358 }
359
360
361 static int __ieee80211_start_scan(struct ieee80211_sub_if_data *sdata,
362                                   struct cfg80211_scan_request *req)
363 {
364         struct ieee80211_local *local = sdata->local;
365         int rc;
366
367         lockdep_assert_held(&local->mtx);
368
369         if (local->scan_req)
370                 return -EBUSY;
371
372         if (!list_empty(&local->work_list)) {
373                 /* wait for the work to finish/time out */
374                 local->scan_req = req;
375                 local->scan_sdata = sdata;
376                 return 0;
377         }
378
379         if (local->ops->hw_scan) {
380                 u8 *ies;
381
382                 local->hw_scan_req = kmalloc(
383                                 sizeof(*local->hw_scan_req) +
384                                 req->n_channels * sizeof(req->channels[0]) +
385                                 2 + IEEE80211_MAX_SSID_LEN + local->scan_ies_len +
386                                 req->ie_len, GFP_KERNEL);
387                 if (!local->hw_scan_req)
388                         return -ENOMEM;
389
390                 local->hw_scan_req->ssids = req->ssids;
391                 local->hw_scan_req->n_ssids = req->n_ssids;
392                 ies = (u8 *)local->hw_scan_req +
393                         sizeof(*local->hw_scan_req) +
394                         req->n_channels * sizeof(req->channels[0]);
395                 local->hw_scan_req->ie = ies;
396
397                 local->hw_scan_band = 0;
398
399                 /*
400                  * After allocating local->hw_scan_req, we must
401                  * go through until ieee80211_prep_hw_scan(), so
402                  * anything that might be changed here and leave
403                  * this function early must not go after this
404                  * allocation.
405                  */
406         }
407
408         local->scan_req = req;
409         local->scan_sdata = sdata;
410
411         if (local->ops->hw_scan)
412                 __set_bit(SCAN_HW_SCANNING, &local->scanning);
413         else
414                 __set_bit(SCAN_SW_SCANNING, &local->scanning);
415
416         ieee80211_recalc_idle(local);
417
418         if (local->ops->hw_scan) {
419                 WARN_ON(!ieee80211_prep_hw_scan(local));
420                 rc = drv_hw_scan(local, sdata, local->hw_scan_req);
421         } else
422                 rc = ieee80211_start_sw_scan(local);
423
424         if (rc) {
425                 kfree(local->hw_scan_req);
426                 local->hw_scan_req = NULL;
427                 local->scanning = 0;
428
429                 ieee80211_recalc_idle(local);
430
431                 local->scan_req = NULL;
432                 local->scan_sdata = NULL;
433         }
434
435         return rc;
436 }
437
438 static unsigned long
439 ieee80211_scan_get_channel_time(struct ieee80211_channel *chan)
440 {
441         /*
442          * TODO: channel switching also consumes quite some time,
443          * add that delay as well to get a better estimation
444          */
445         if (chan->flags & IEEE80211_CHAN_PASSIVE_SCAN)
446                 return IEEE80211_PASSIVE_CHANNEL_TIME;
447         return IEEE80211_PROBE_DELAY + IEEE80211_CHANNEL_TIME;
448 }
449
450 static void ieee80211_scan_state_decision(struct ieee80211_local *local,
451                                           unsigned long *next_delay)
452 {
453         bool associated = false;
454         bool tx_empty = true;
455         bool bad_latency;
456         bool listen_int_exceeded;
457         unsigned long min_beacon_int = 0;
458         struct ieee80211_sub_if_data *sdata;
459         struct ieee80211_channel *next_chan;
460
461         /*
462          * check if at least one STA interface is associated,
463          * check if at least one STA interface has pending tx frames
464          * and grab the lowest used beacon interval
465          */
466         mutex_lock(&local->iflist_mtx);
467         list_for_each_entry(sdata, &local->interfaces, list) {
468                 if (!ieee80211_sdata_running(sdata))
469                         continue;
470
471                 if (sdata->vif.type == NL80211_IFTYPE_STATION) {
472                         if (sdata->u.mgd.associated) {
473                                 associated = true;
474
475                                 if (sdata->vif.bss_conf.beacon_int <
476                                     min_beacon_int || min_beacon_int == 0)
477                                         min_beacon_int =
478                                                 sdata->vif.bss_conf.beacon_int;
479
480                                 if (!qdisc_all_tx_empty(sdata->dev)) {
481                                         tx_empty = false;
482                                         break;
483                                 }
484                         }
485                 }
486         }
487         mutex_unlock(&local->iflist_mtx);
488
489         if (local->scan_channel) {
490                 /*
491                  * we're currently scanning a different channel, let's
492                  * see if we can scan another channel without interfering
493                  * with the current traffic situation.
494                  *
495                  * Since we don't know if the AP has pending frames for us
496                  * we can only check for our tx queues and use the current
497                  * pm_qos requirements for rx. Hence, if no tx traffic occurs
498                  * at all we will scan as many channels in a row as the pm_qos
499                  * latency allows us to. Additionally we also check for the
500                  * currently negotiated listen interval to prevent losing
501                  * frames unnecessarily.
502                  *
503                  * Otherwise switch back to the operating channel.
504                  */
505                 next_chan = local->scan_req->channels[local->scan_channel_idx];
506
507                 bad_latency = time_after(jiffies +
508                                 ieee80211_scan_get_channel_time(next_chan),
509                                 local->leave_oper_channel_time +
510                                 usecs_to_jiffies(pm_qos_request(PM_QOS_NETWORK_LATENCY)));
511
512                 listen_int_exceeded = time_after(jiffies +
513                                 ieee80211_scan_get_channel_time(next_chan),
514                                 local->leave_oper_channel_time +
515                                 usecs_to_jiffies(min_beacon_int * 1024) *
516                                 local->hw.conf.listen_interval);
517
518                 if (associated && ( !tx_empty || bad_latency ||
519                     listen_int_exceeded))
520                         local->next_scan_state = SCAN_ENTER_OPER_CHANNEL;
521                 else
522                         local->next_scan_state = SCAN_SET_CHANNEL;
523         } else {
524                 /*
525                  * we're on the operating channel currently, let's
526                  * leave that channel now to scan another one
527                  */
528                 local->next_scan_state = SCAN_LEAVE_OPER_CHANNEL;
529         }
530
531         *next_delay = 0;
532 }
533
534 static void ieee80211_scan_state_leave_oper_channel(struct ieee80211_local *local,
535                                                     unsigned long *next_delay)
536 {
537         ieee80211_offchannel_stop_station(local);
538
539         __set_bit(SCAN_OFF_CHANNEL, &local->scanning);
540
541         /*
542          * What if the nullfunc frames didn't arrive?
543          */
544         drv_flush(local, false);
545         if (local->ops->flush)
546                 *next_delay = 0;
547         else
548                 *next_delay = HZ / 10;
549
550         /* remember when we left the operating channel */
551         local->leave_oper_channel_time = jiffies;
552
553         /* advance to the next channel to be scanned */
554         local->next_scan_state = SCAN_SET_CHANNEL;
555 }
556
557 static void ieee80211_scan_state_enter_oper_channel(struct ieee80211_local *local,
558                                                     unsigned long *next_delay)
559 {
560         /* switch back to the operating channel */
561         local->scan_channel = NULL;
562         ieee80211_hw_config(local, IEEE80211_CONF_CHANGE_CHANNEL);
563
564         /*
565          * Only re-enable station mode interface now; beaconing will be
566          * re-enabled once the full scan has been completed.
567          */
568         ieee80211_offchannel_return(local, false);
569
570         __clear_bit(SCAN_OFF_CHANNEL, &local->scanning);
571
572         *next_delay = HZ / 5;
573         local->next_scan_state = SCAN_DECISION;
574 }
575
576 static void ieee80211_scan_state_set_channel(struct ieee80211_local *local,
577                                              unsigned long *next_delay)
578 {
579         int skip;
580         struct ieee80211_channel *chan;
581
582         skip = 0;
583         chan = local->scan_req->channels[local->scan_channel_idx];
584
585         local->scan_channel = chan;
586         if (ieee80211_hw_config(local, IEEE80211_CONF_CHANGE_CHANNEL))
587                 skip = 1;
588
589         /* advance state machine to next channel/band */
590         local->scan_channel_idx++;
591
592         if (skip) {
593                 /* if we skip this channel return to the decision state */
594                 local->next_scan_state = SCAN_DECISION;
595                 return;
596         }
597
598         /*
599          * Probe delay is used to update the NAV, cf. 11.1.3.2.2
600          * (which unfortunately doesn't say _why_ step a) is done,
601          * but it waits for the probe delay or until a frame is
602          * received - and the received frame would update the NAV).
603          * For now, we do not support waiting until a frame is
604          * received.
605          *
606          * In any case, it is not necessary for a passive scan.
607          */
608         if (chan->flags & IEEE80211_CHAN_PASSIVE_SCAN ||
609             !local->scan_req->n_ssids) {
610                 *next_delay = IEEE80211_PASSIVE_CHANNEL_TIME;
611                 local->next_scan_state = SCAN_DECISION;
612                 return;
613         }
614
615         /* active scan, send probes */
616         *next_delay = IEEE80211_PROBE_DELAY;
617         local->next_scan_state = SCAN_SEND_PROBE;
618 }
619
620 static void ieee80211_scan_state_send_probe(struct ieee80211_local *local,
621                                             unsigned long *next_delay)
622 {
623         int i;
624         struct ieee80211_sub_if_data *sdata = local->scan_sdata;
625
626         for (i = 0; i < local->scan_req->n_ssids; i++)
627                 ieee80211_send_probe_req(
628                         sdata, NULL,
629                         local->scan_req->ssids[i].ssid,
630                         local->scan_req->ssids[i].ssid_len,
631                         local->scan_req->ie, local->scan_req->ie_len);
632
633         /*
634          * After sending probe requests, wait for probe responses
635          * on the channel.
636          */
637         *next_delay = IEEE80211_CHANNEL_TIME;
638         local->next_scan_state = SCAN_DECISION;
639 }
640
641 void ieee80211_scan_work(struct work_struct *work)
642 {
643         struct ieee80211_local *local =
644                 container_of(work, struct ieee80211_local, scan_work.work);
645         struct ieee80211_sub_if_data *sdata = local->scan_sdata;
646         unsigned long next_delay = 0;
647         bool aborted, hw_scan, finish;
648
649         mutex_lock(&local->mtx);
650
651         if (test_and_clear_bit(SCAN_COMPLETED, &local->scanning)) {
652                 aborted = test_and_clear_bit(SCAN_ABORTED, &local->scanning);
653                 goto out_complete;
654         }
655
656         if (!sdata || !local->scan_req)
657                 goto out;
658
659         if (local->hw_scan_req) {
660                 int rc = drv_hw_scan(local, sdata, local->hw_scan_req);
661                 if (rc) {
662                         aborted = true;
663                         goto out_complete;
664                 } else
665                         goto out;
666         }
667
668         if (local->scan_req && !local->scanning) {
669                 struct cfg80211_scan_request *req = local->scan_req;
670                 int rc;
671
672                 local->scan_req = NULL;
673                 local->scan_sdata = NULL;
674
675                 rc = __ieee80211_start_scan(sdata, req);
676                 if (rc) {
677                         aborted = true;
678                         goto out_complete;
679                 } else
680                         goto out;
681         }
682
683         /*
684          * Avoid re-scheduling when the sdata is going away.
685          */
686         if (!ieee80211_sdata_running(sdata)) {
687                 aborted = true;
688                 goto out_complete;
689         }
690
691         mutex_unlock(&local->mtx);
692
693         /*
694          * as long as no delay is required advance immediately
695          * without scheduling a new work
696          */
697         do {
698                 switch (local->next_scan_state) {
699                 case SCAN_DECISION:
700                         /* if no more bands/channels left, complete scan */
701                         if (local->scan_channel_idx >= local->scan_req->n_channels) {
702                                 aborted = false;
703                                 goto out_complete;
704                         }
705                         ieee80211_scan_state_decision(local, &next_delay);
706                         break;
707                 case SCAN_SET_CHANNEL:
708                         ieee80211_scan_state_set_channel(local, &next_delay);
709                         break;
710                 case SCAN_SEND_PROBE:
711                         ieee80211_scan_state_send_probe(local, &next_delay);
712                         break;
713                 case SCAN_LEAVE_OPER_CHANNEL:
714                         ieee80211_scan_state_leave_oper_channel(local, &next_delay);
715                         break;
716                 case SCAN_ENTER_OPER_CHANNEL:
717                         ieee80211_scan_state_enter_oper_channel(local, &next_delay);
718                         break;
719                 }
720         } while (next_delay == 0);
721
722         ieee80211_queue_delayed_work(&local->hw, &local->scan_work, next_delay);
723         return;
724
725 out_complete:
726         hw_scan = test_bit(SCAN_HW_SCANNING, &local->scanning);
727         finish = __ieee80211_scan_completed(&local->hw, aborted, hw_scan);
728         mutex_unlock(&local->mtx);
729         if (finish)
730                 __ieee80211_scan_completed_finish(&local->hw, hw_scan);
731         return;
732
733 out:
734         mutex_unlock(&local->mtx);
735 }
736
737 int ieee80211_request_scan(struct ieee80211_sub_if_data *sdata,
738                            struct cfg80211_scan_request *req)
739 {
740         int res;
741
742         mutex_lock(&sdata->local->mtx);
743         res = __ieee80211_start_scan(sdata, req);
744         mutex_unlock(&sdata->local->mtx);
745
746         return res;
747 }
748
749 int ieee80211_request_internal_scan(struct ieee80211_sub_if_data *sdata,
750                                     const u8 *ssid, u8 ssid_len,
751                                     struct ieee80211_channel *chan)
752 {
753         struct ieee80211_local *local = sdata->local;
754         int ret = -EBUSY;
755         enum ieee80211_band band;
756
757         mutex_lock(&local->mtx);
758
759         /* busy scanning */
760         if (local->scan_req)
761                 goto unlock;
762
763         /* fill internal scan request */
764         if (!chan) {
765                 int i, nchan = 0;
766
767                 for (band = 0; band < IEEE80211_NUM_BANDS; band++) {
768                         if (!local->hw.wiphy->bands[band])
769                                 continue;
770                         for (i = 0;
771                              i < local->hw.wiphy->bands[band]->n_channels;
772                              i++) {
773                                 local->int_scan_req->channels[nchan] =
774                                     &local->hw.wiphy->bands[band]->channels[i];
775                                 nchan++;
776                         }
777                 }
778
779                 local->int_scan_req->n_channels = nchan;
780         } else {
781                 local->int_scan_req->channels[0] = chan;
782                 local->int_scan_req->n_channels = 1;
783         }
784
785         local->int_scan_req->ssids = &local->scan_ssid;
786         local->int_scan_req->n_ssids = 1;
787         memcpy(local->int_scan_req->ssids[0].ssid, ssid, IEEE80211_MAX_SSID_LEN);
788         local->int_scan_req->ssids[0].ssid_len = ssid_len;
789
790         ret = __ieee80211_start_scan(sdata, sdata->local->int_scan_req);
791  unlock:
792         mutex_unlock(&local->mtx);
793         return ret;
794 }
795
796 /*
797  * Only call this function when a scan can't be queued -- under RTNL.
798  */
799 void ieee80211_scan_cancel(struct ieee80211_local *local)
800 {
801         bool abortscan, finish;
802
803         /*
804          * We are only canceling software scan, or deferred scan that was not
805          * yet really started (see __ieee80211_start_scan ).
806          *
807          * Regarding hardware scan:
808          * - we can not call  __ieee80211_scan_completed() as when
809          *   SCAN_HW_SCANNING bit is set this function change
810          *   local->hw_scan_req to operate on 5G band, what race with
811          *   driver which can use local->hw_scan_req
812          *
813          * - we can not cancel scan_work since driver can schedule it
814          *   by ieee80211_scan_completed(..., true) to finish scan
815          *
816          * Hence low lever driver is responsible for canceling HW scan.
817          */
818
819         mutex_lock(&local->mtx);
820         abortscan = local->scan_req && !test_bit(SCAN_HW_SCANNING, &local->scanning);
821         if (abortscan)
822                 finish = __ieee80211_scan_completed(&local->hw, true, false);
823         mutex_unlock(&local->mtx);
824
825         if (abortscan) {
826                 /* The scan is canceled, but stop work from being pending */
827                 cancel_delayed_work_sync(&local->scan_work);
828                 if (finish)
829                         __ieee80211_scan_completed_finish(&local->hw, false);
830         }
831 }