mac80211: improve IBSS scanning
[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, srlen;
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         /* replace old supported rates if we get new values */
117         srlen = 0;
118         if (elems->supp_rates) {
119                 clen = IEEE80211_MAX_SUPP_RATES;
120                 if (clen > elems->supp_rates_len)
121                         clen = elems->supp_rates_len;
122                 memcpy(bss->supp_rates, elems->supp_rates, clen);
123                 srlen += clen;
124         }
125         if (elems->ext_supp_rates) {
126                 clen = IEEE80211_MAX_SUPP_RATES - srlen;
127                 if (clen > elems->ext_supp_rates_len)
128                         clen = elems->ext_supp_rates_len;
129                 memcpy(bss->supp_rates + srlen, elems->ext_supp_rates, clen);
130                 srlen += clen;
131         }
132         if (srlen)
133                 bss->supp_rates_len = srlen;
134
135         bss->wmm_used = elems->wmm_param || elems->wmm_info;
136         bss->uapsd_supported = is_uapsd_supported(elems);
137
138         if (!beacon)
139                 bss->last_probe_resp = jiffies;
140
141         return bss;
142 }
143
144 ieee80211_rx_result
145 ieee80211_scan_rx(struct ieee80211_sub_if_data *sdata, struct sk_buff *skb)
146 {
147         struct ieee80211_rx_status *rx_status = IEEE80211_SKB_RXCB(skb);
148         struct ieee80211_mgmt *mgmt;
149         struct ieee80211_bss *bss;
150         u8 *elements;
151         struct ieee80211_channel *channel;
152         size_t baselen;
153         int freq;
154         __le16 fc;
155         bool presp, beacon = false;
156         struct ieee802_11_elems elems;
157
158         if (skb->len < 2)
159                 return RX_DROP_UNUSABLE;
160
161         mgmt = (struct ieee80211_mgmt *) skb->data;
162         fc = mgmt->frame_control;
163
164         if (ieee80211_is_ctl(fc))
165                 return RX_CONTINUE;
166
167         if (skb->len < 24)
168                 return RX_DROP_MONITOR;
169
170         presp = ieee80211_is_probe_resp(fc);
171         if (presp) {
172                 /* ignore ProbeResp to foreign address */
173                 if (memcmp(mgmt->da, sdata->vif.addr, ETH_ALEN))
174                         return RX_DROP_MONITOR;
175
176                 presp = true;
177                 elements = mgmt->u.probe_resp.variable;
178                 baselen = offsetof(struct ieee80211_mgmt, u.probe_resp.variable);
179         } else {
180                 beacon = ieee80211_is_beacon(fc);
181                 baselen = offsetof(struct ieee80211_mgmt, u.beacon.variable);
182                 elements = mgmt->u.beacon.variable;
183         }
184
185         if (!presp && !beacon)
186                 return RX_CONTINUE;
187
188         if (baselen > skb->len)
189                 return RX_DROP_MONITOR;
190
191         ieee802_11_parse_elems(elements, skb->len - baselen, &elems);
192
193         if (elems.ds_params && elems.ds_params_len == 1)
194                 freq = ieee80211_channel_to_frequency(elems.ds_params[0]);
195         else
196                 freq = rx_status->freq;
197
198         channel = ieee80211_get_channel(sdata->local->hw.wiphy, freq);
199
200         if (!channel || channel->flags & IEEE80211_CHAN_DISABLED)
201                 return RX_DROP_MONITOR;
202
203         bss = ieee80211_bss_info_update(sdata->local, rx_status,
204                                         mgmt, skb->len, &elems,
205                                         channel, beacon);
206         if (bss)
207                 ieee80211_rx_bss_put(sdata->local, bss);
208
209         dev_kfree_skb(skb);
210         return RX_QUEUED;
211 }
212
213 /* return false if no more work */
214 static bool ieee80211_prep_hw_scan(struct ieee80211_local *local)
215 {
216         struct cfg80211_scan_request *req = local->scan_req;
217         enum ieee80211_band band;
218         int i, ielen, n_chans;
219
220         do {
221                 if (local->hw_scan_band == IEEE80211_NUM_BANDS)
222                         return false;
223
224                 band = local->hw_scan_band;
225                 n_chans = 0;
226                 for (i = 0; i < req->n_channels; i++) {
227                         if (req->channels[i]->band == band) {
228                                 local->hw_scan_req->channels[n_chans] =
229                                                         req->channels[i];
230                                 n_chans++;
231                         }
232                 }
233
234                 local->hw_scan_band++;
235         } while (!n_chans);
236
237         local->hw_scan_req->n_channels = n_chans;
238
239         ielen = ieee80211_build_preq_ies(local, (u8 *)local->hw_scan_req->ie,
240                                          req->ie, req->ie_len, band);
241         local->hw_scan_req->ie_len = ielen;
242
243         return true;
244 }
245
246 void ieee80211_scan_completed(struct ieee80211_hw *hw, bool aborted)
247 {
248         struct ieee80211_local *local = hw_to_local(hw);
249         bool was_hw_scan;
250
251         trace_api_scan_completed(local, aborted);
252
253         mutex_lock(&local->scan_mtx);
254
255         /*
256          * It's ok to abort a not-yet-running scan (that
257          * we have one at all will be verified by checking
258          * local->scan_req next), but not to complete it
259          * successfully.
260          */
261         if (WARN_ON(!local->scanning && !aborted))
262                 aborted = true;
263
264         if (WARN_ON(!local->scan_req)) {
265                 mutex_unlock(&local->scan_mtx);
266                 return;
267         }
268
269         was_hw_scan = test_bit(SCAN_HW_SCANNING, &local->scanning);
270         if (was_hw_scan && !aborted && ieee80211_prep_hw_scan(local)) {
271                 ieee80211_queue_delayed_work(&local->hw,
272                                              &local->scan_work, 0);
273                 mutex_unlock(&local->scan_mtx);
274                 return;
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         /* we only have to protect scan_req and hw/sw scan */
289         mutex_unlock(&local->scan_mtx);
290
291         ieee80211_hw_config(local, IEEE80211_CONF_CHANGE_CHANNEL);
292         if (was_hw_scan)
293                 goto done;
294
295         ieee80211_configure_filter(local);
296
297         drv_sw_scan_complete(local);
298
299         ieee80211_offchannel_return(local, true);
300
301  done:
302         ieee80211_recalc_idle(local);
303         ieee80211_mlme_notify_scan_completed(local);
304         ieee80211_ibss_notify_scan_completed(local);
305         ieee80211_mesh_notify_scan_completed(local);
306         ieee80211_queue_work(&local->hw, &local->work_work);
307 }
308 EXPORT_SYMBOL(ieee80211_scan_completed);
309
310 static int ieee80211_start_sw_scan(struct ieee80211_local *local)
311 {
312         /*
313          * Hardware/driver doesn't support hw_scan, so use software
314          * scanning instead. First send a nullfunc frame with power save
315          * bit on so that AP will buffer the frames for us while we are not
316          * listening, then send probe requests to each channel and wait for
317          * the responses. After all channels are scanned, tune back to the
318          * original channel and send a nullfunc frame with power save bit
319          * off to trigger the AP to send us all the buffered frames.
320          *
321          * Note that while local->sw_scanning is true everything else but
322          * nullfunc frames and probe requests will be dropped in
323          * ieee80211_tx_h_check_assoc().
324          */
325         drv_sw_scan_start(local);
326
327         ieee80211_offchannel_stop_beaconing(local);
328
329         local->leave_oper_channel_time = 0;
330         local->next_scan_state = SCAN_DECISION;
331         local->scan_channel_idx = 0;
332
333         drv_flush(local, false);
334
335         ieee80211_configure_filter(local);
336
337         ieee80211_queue_delayed_work(&local->hw,
338                                      &local->scan_work,
339                                      IEEE80211_CHANNEL_TIME);
340
341         return 0;
342 }
343
344
345 static int __ieee80211_start_scan(struct ieee80211_sub_if_data *sdata,
346                                   struct cfg80211_scan_request *req)
347 {
348         struct ieee80211_local *local = sdata->local;
349         int rc;
350
351         if (local->scan_req)
352                 return -EBUSY;
353
354         if (!list_empty(&local->work_list)) {
355                 /* wait for the work to finish/time out */
356                 local->scan_req = req;
357                 local->scan_sdata = sdata;
358                 return 0;
359         }
360
361         if (local->ops->hw_scan) {
362                 u8 *ies;
363
364                 local->hw_scan_req = kmalloc(
365                                 sizeof(*local->hw_scan_req) +
366                                 req->n_channels * sizeof(req->channels[0]) +
367                                 2 + IEEE80211_MAX_SSID_LEN + local->scan_ies_len +
368                                 req->ie_len, GFP_KERNEL);
369                 if (!local->hw_scan_req)
370                         return -ENOMEM;
371
372                 local->hw_scan_req->ssids = req->ssids;
373                 local->hw_scan_req->n_ssids = req->n_ssids;
374                 ies = (u8 *)local->hw_scan_req +
375                         sizeof(*local->hw_scan_req) +
376                         req->n_channels * sizeof(req->channels[0]);
377                 local->hw_scan_req->ie = ies;
378
379                 local->hw_scan_band = 0;
380
381                 /*
382                  * After allocating local->hw_scan_req, we must
383                  * go through until ieee80211_prep_hw_scan(), so
384                  * anything that might be changed here and leave
385                  * this function early must not go after this
386                  * allocation.
387                  */
388         }
389
390         local->scan_req = req;
391         local->scan_sdata = sdata;
392
393         if (local->ops->hw_scan)
394                 __set_bit(SCAN_HW_SCANNING, &local->scanning);
395         else
396                 __set_bit(SCAN_SW_SCANNING, &local->scanning);
397
398         /*
399          * Kicking off the scan need not be protected,
400          * only the scan variable stuff, since now
401          * local->scan_req is assigned and other callers
402          * will abort their scan attempts.
403          *
404          * This avoids too many locking dependencies
405          * so that the scan completed calls have more
406          * locking freedom.
407          */
408
409         ieee80211_recalc_idle(local);
410         mutex_unlock(&local->scan_mtx);
411
412         if (local->ops->hw_scan) {
413                 WARN_ON(!ieee80211_prep_hw_scan(local));
414                 rc = drv_hw_scan(local, sdata, local->hw_scan_req);
415         } else
416                 rc = ieee80211_start_sw_scan(local);
417
418         mutex_lock(&local->scan_mtx);
419
420         if (rc) {
421                 kfree(local->hw_scan_req);
422                 local->hw_scan_req = NULL;
423                 local->scanning = 0;
424
425                 ieee80211_recalc_idle(local);
426
427                 local->scan_req = NULL;
428                 local->scan_sdata = NULL;
429         }
430
431         return rc;
432 }
433
434 static unsigned long
435 ieee80211_scan_get_channel_time(struct ieee80211_channel *chan)
436 {
437         /*
438          * TODO: channel switching also consumes quite some time,
439          * add that delay as well to get a better estimation
440          */
441         if (chan->flags & IEEE80211_CHAN_PASSIVE_SCAN)
442                 return IEEE80211_PASSIVE_CHANNEL_TIME;
443         return IEEE80211_PROBE_DELAY + IEEE80211_CHANNEL_TIME;
444 }
445
446 static int ieee80211_scan_state_decision(struct ieee80211_local *local,
447                                          unsigned long *next_delay)
448 {
449         bool associated = false;
450         bool tx_empty = true;
451         bool bad_latency;
452         bool listen_int_exceeded;
453         unsigned long min_beacon_int = 0;
454         struct ieee80211_sub_if_data *sdata;
455         struct ieee80211_channel *next_chan;
456
457         /* if no more bands/channels left, complete scan and advance to the idle state */
458         if (local->scan_channel_idx >= local->scan_req->n_channels) {
459                 ieee80211_scan_completed(&local->hw, false);
460                 return 1;
461         }
462
463         /*
464          * check if at least one STA interface is associated,
465          * check if at least one STA interface has pending tx frames
466          * and grab the lowest used beacon interval
467          */
468         mutex_lock(&local->iflist_mtx);
469         list_for_each_entry(sdata, &local->interfaces, list) {
470                 if (!ieee80211_sdata_running(sdata))
471                         continue;
472
473                 if (sdata->vif.type == NL80211_IFTYPE_STATION) {
474                         if (sdata->u.mgd.associated) {
475                                 associated = true;
476
477                                 if (sdata->vif.bss_conf.beacon_int <
478                                     min_beacon_int || min_beacon_int == 0)
479                                         min_beacon_int =
480                                                 sdata->vif.bss_conf.beacon_int;
481
482                                 if (!qdisc_all_tx_empty(sdata->dev)) {
483                                         tx_empty = false;
484                                         break;
485                                 }
486                         }
487                 }
488         }
489         mutex_unlock(&local->iflist_mtx);
490
491         if (local->scan_channel) {
492                 /*
493                  * we're currently scanning a different channel, let's
494                  * see if we can scan another channel without interfering
495                  * with the current traffic situation.
496                  *
497                  * Since we don't know if the AP has pending frames for us
498                  * we can only check for our tx queues and use the current
499                  * pm_qos requirements for rx. Hence, if no tx traffic occurs
500                  * at all we will scan as many channels in a row as the pm_qos
501                  * latency allows us to. Additionally we also check for the
502                  * currently negotiated listen interval to prevent losing
503                  * frames unnecessarily.
504                  *
505                  * Otherwise switch back to the operating channel.
506                  */
507                 next_chan = local->scan_req->channels[local->scan_channel_idx];
508
509                 bad_latency = time_after(jiffies +
510                                 ieee80211_scan_get_channel_time(next_chan),
511                                 local->leave_oper_channel_time +
512                                 usecs_to_jiffies(pm_qos_requirement(PM_QOS_NETWORK_LATENCY)));
513
514                 listen_int_exceeded = time_after(jiffies +
515                                 ieee80211_scan_get_channel_time(next_chan),
516                                 local->leave_oper_channel_time +
517                                 usecs_to_jiffies(min_beacon_int * 1024) *
518                                 local->hw.conf.listen_interval);
519
520                 if (associated && ( !tx_empty || bad_latency ||
521                     listen_int_exceeded))
522                         local->next_scan_state = SCAN_ENTER_OPER_CHANNEL;
523                 else
524                         local->next_scan_state = SCAN_SET_CHANNEL;
525         } else {
526                 /*
527                  * we're on the operating channel currently, let's
528                  * leave that channel now to scan another one
529                  */
530                 local->next_scan_state = SCAN_LEAVE_OPER_CHANNEL;
531         }
532
533         *next_delay = 0;
534         return 0;
535 }
536
537 static void ieee80211_scan_state_leave_oper_channel(struct ieee80211_local *local,
538                                                     unsigned long *next_delay)
539 {
540         ieee80211_offchannel_stop_station(local);
541
542         __set_bit(SCAN_OFF_CHANNEL, &local->scanning);
543
544         /*
545          * What if the nullfunc frames didn't arrive?
546          */
547         drv_flush(local, false);
548         if (local->ops->flush)
549                 *next_delay = 0;
550         else
551                 *next_delay = HZ / 10;
552
553         /* remember when we left the operating channel */
554         local->leave_oper_channel_time = jiffies;
555
556         /* advance to the next channel to be scanned */
557         local->next_scan_state = SCAN_SET_CHANNEL;
558 }
559
560 static void ieee80211_scan_state_enter_oper_channel(struct ieee80211_local *local,
561                                                     unsigned long *next_delay)
562 {
563         /* switch back to the operating channel */
564         local->scan_channel = NULL;
565         ieee80211_hw_config(local, IEEE80211_CONF_CHANGE_CHANNEL);
566
567         /*
568          * Only re-enable station mode interface now; beaconing will be
569          * re-enabled once the full scan has been completed.
570          */
571         ieee80211_offchannel_return(local, false);
572
573         __clear_bit(SCAN_OFF_CHANNEL, &local->scanning);
574
575         *next_delay = HZ / 5;
576         local->next_scan_state = SCAN_DECISION;
577 }
578
579 static void ieee80211_scan_state_set_channel(struct ieee80211_local *local,
580                                              unsigned long *next_delay)
581 {
582         int skip;
583         struct ieee80211_channel *chan;
584
585         skip = 0;
586         chan = local->scan_req->channels[local->scan_channel_idx];
587
588         local->scan_channel = chan;
589         if (ieee80211_hw_config(local, IEEE80211_CONF_CHANGE_CHANNEL))
590                 skip = 1;
591
592         /* advance state machine to next channel/band */
593         local->scan_channel_idx++;
594
595         if (skip) {
596                 /* if we skip this channel return to the decision state */
597                 local->next_scan_state = SCAN_DECISION;
598                 return;
599         }
600
601         /*
602          * Probe delay is used to update the NAV, cf. 11.1.3.2.2
603          * (which unfortunately doesn't say _why_ step a) is done,
604          * but it waits for the probe delay or until a frame is
605          * received - and the received frame would update the NAV).
606          * For now, we do not support waiting until a frame is
607          * received.
608          *
609          * In any case, it is not necessary for a passive scan.
610          */
611         if (chan->flags & IEEE80211_CHAN_PASSIVE_SCAN ||
612             !local->scan_req->n_ssids) {
613                 *next_delay = IEEE80211_PASSIVE_CHANNEL_TIME;
614                 local->next_scan_state = SCAN_DECISION;
615                 return;
616         }
617
618         /* active scan, send probes */
619         *next_delay = IEEE80211_PROBE_DELAY;
620         local->next_scan_state = SCAN_SEND_PROBE;
621 }
622
623 static void ieee80211_scan_state_send_probe(struct ieee80211_local *local,
624                                             unsigned long *next_delay)
625 {
626         int i;
627         struct ieee80211_sub_if_data *sdata = local->scan_sdata;
628
629         for (i = 0; i < local->scan_req->n_ssids; i++)
630                 ieee80211_send_probe_req(
631                         sdata, NULL,
632                         local->scan_req->ssids[i].ssid,
633                         local->scan_req->ssids[i].ssid_len,
634                         local->scan_req->ie, local->scan_req->ie_len);
635
636         /*
637          * After sending probe requests, wait for probe responses
638          * on the channel.
639          */
640         *next_delay = IEEE80211_CHANNEL_TIME;
641         local->next_scan_state = SCAN_DECISION;
642 }
643
644 void ieee80211_scan_work(struct work_struct *work)
645 {
646         struct ieee80211_local *local =
647                 container_of(work, struct ieee80211_local, scan_work.work);
648         struct ieee80211_sub_if_data *sdata = local->scan_sdata;
649         unsigned long next_delay = 0;
650
651         mutex_lock(&local->scan_mtx);
652         if (!sdata || !local->scan_req) {
653                 mutex_unlock(&local->scan_mtx);
654                 return;
655         }
656
657         if (local->hw_scan_req) {
658                 int rc = drv_hw_scan(local, sdata, local->hw_scan_req);
659                 mutex_unlock(&local->scan_mtx);
660                 if (rc)
661                         ieee80211_scan_completed(&local->hw, true);
662                 return;
663         }
664
665         if (local->scan_req && !local->scanning) {
666                 struct cfg80211_scan_request *req = local->scan_req;
667                 int rc;
668
669                 local->scan_req = NULL;
670                 local->scan_sdata = NULL;
671
672                 rc = __ieee80211_start_scan(sdata, req);
673                 mutex_unlock(&local->scan_mtx);
674
675                 if (rc)
676                         ieee80211_scan_completed(&local->hw, true);
677                 return;
678         }
679
680         mutex_unlock(&local->scan_mtx);
681
682         /*
683          * Avoid re-scheduling when the sdata is going away.
684          */
685         if (!ieee80211_sdata_running(sdata)) {
686                 ieee80211_scan_completed(&local->hw, true);
687                 return;
688         }
689
690         /*
691          * as long as no delay is required advance immediately
692          * without scheduling a new work
693          */
694         do {
695                 switch (local->next_scan_state) {
696                 case SCAN_DECISION:
697                         if (ieee80211_scan_state_decision(local, &next_delay))
698                                 return;
699                         break;
700                 case SCAN_SET_CHANNEL:
701                         ieee80211_scan_state_set_channel(local, &next_delay);
702                         break;
703                 case SCAN_SEND_PROBE:
704                         ieee80211_scan_state_send_probe(local, &next_delay);
705                         break;
706                 case SCAN_LEAVE_OPER_CHANNEL:
707                         ieee80211_scan_state_leave_oper_channel(local, &next_delay);
708                         break;
709                 case SCAN_ENTER_OPER_CHANNEL:
710                         ieee80211_scan_state_enter_oper_channel(local, &next_delay);
711                         break;
712                 }
713         } while (next_delay == 0);
714
715         ieee80211_queue_delayed_work(&local->hw, &local->scan_work, next_delay);
716 }
717
718 int ieee80211_request_scan(struct ieee80211_sub_if_data *sdata,
719                            struct cfg80211_scan_request *req)
720 {
721         int res;
722
723         mutex_lock(&sdata->local->scan_mtx);
724         res = __ieee80211_start_scan(sdata, req);
725         mutex_unlock(&sdata->local->scan_mtx);
726
727         return res;
728 }
729
730 int ieee80211_request_internal_scan(struct ieee80211_sub_if_data *sdata,
731                                     const u8 *ssid, u8 ssid_len,
732                                     struct ieee80211_channel *chan)
733 {
734         struct ieee80211_local *local = sdata->local;
735         int ret = -EBUSY;
736         enum nl80211_band band;
737
738         mutex_lock(&local->scan_mtx);
739
740         /* busy scanning */
741         if (local->scan_req)
742                 goto unlock;
743
744         /* fill internal scan request */
745         if (!chan) {
746                 int i, nchan = 0;
747
748                 for (band = 0; band < IEEE80211_NUM_BANDS; band++) {
749                         if (!local->hw.wiphy->bands[band])
750                                 continue;
751                         for (i = 0;
752                              i < local->hw.wiphy->bands[band]->n_channels;
753                              i++) {
754                                 local->int_scan_req->channels[nchan] =
755                                     &local->hw.wiphy->bands[band]->channels[i];
756                                 nchan++;
757                         }
758                 }
759
760                 local->int_scan_req->n_channels = nchan;
761         } else {
762                 local->int_scan_req->channels[0] = chan;
763                 local->int_scan_req->n_channels = 1;
764         }
765
766         local->int_scan_req->ssids = &local->scan_ssid;
767         local->int_scan_req->n_ssids = 1;
768         memcpy(local->int_scan_req->ssids[0].ssid, ssid, IEEE80211_MAX_SSID_LEN);
769         local->int_scan_req->ssids[0].ssid_len = ssid_len;
770
771         ret = __ieee80211_start_scan(sdata, sdata->local->int_scan_req);
772  unlock:
773         mutex_unlock(&local->scan_mtx);
774         return ret;
775 }
776
777 void ieee80211_scan_cancel(struct ieee80211_local *local)
778 {
779         bool abortscan;
780
781         cancel_delayed_work_sync(&local->scan_work);
782
783         /*
784          * Only call this function when a scan can't be
785          * queued -- mostly at suspend under RTNL.
786          */
787         mutex_lock(&local->scan_mtx);
788         abortscan = test_bit(SCAN_SW_SCANNING, &local->scanning) ||
789                     (!local->scanning && local->scan_req);
790         mutex_unlock(&local->scan_mtx);
791
792         if (abortscan)
793                 ieee80211_scan_completed(&local->hw, true);
794 }