Merge branch 'master' of git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux
[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.h>
18 #include <net/sch_generic.h>
19 #include <linux/slab.h>
20 #include <linux/export.h>
21 #include <net/mac80211.h>
22
23 #include "ieee80211_i.h"
24 #include "driver-ops.h"
25 #include "mesh.h"
26
27 #define IEEE80211_PROBE_DELAY (HZ / 33)
28 #define IEEE80211_CHANNEL_TIME (HZ / 33)
29 #define IEEE80211_PASSIVE_CHANNEL_TIME (HZ / 8)
30
31 struct ieee80211_bss *
32 ieee80211_rx_bss_get(struct ieee80211_local *local, u8 *bssid, int freq,
33                      u8 *ssid, u8 ssid_len)
34 {
35         struct cfg80211_bss *cbss;
36
37         cbss = cfg80211_get_bss(local->hw.wiphy,
38                                 ieee80211_get_channel(local->hw.wiphy, freq),
39                                 bssid, ssid, ssid_len, 0, 0);
40         if (!cbss)
41                 return NULL;
42         return (void *)cbss->priv;
43 }
44
45 static void ieee80211_rx_bss_free(struct cfg80211_bss *cbss)
46 {
47         struct ieee80211_bss *bss = (void *)cbss->priv;
48
49         kfree(bss_mesh_id(bss));
50         kfree(bss_mesh_cfg(bss));
51 }
52
53 void ieee80211_rx_bss_put(struct ieee80211_local *local,
54                           struct ieee80211_bss *bss)
55 {
56         if (!bss)
57                 return;
58         cfg80211_put_bss(container_of((void *)bss, struct cfg80211_bss, priv));
59 }
60
61 static bool is_uapsd_supported(struct ieee802_11_elems *elems)
62 {
63         u8 qos_info;
64
65         if (elems->wmm_info && elems->wmm_info_len == 7
66             && elems->wmm_info[5] == 1)
67                 qos_info = elems->wmm_info[6];
68         else if (elems->wmm_param && elems->wmm_param_len == 24
69                  && elems->wmm_param[5] == 1)
70                 qos_info = elems->wmm_param[6];
71         else
72                 /* no valid wmm information or parameter element found */
73                 return false;
74
75         return qos_info & IEEE80211_WMM_IE_AP_QOSINFO_UAPSD;
76 }
77
78 struct ieee80211_bss *
79 ieee80211_bss_info_update(struct ieee80211_local *local,
80                           struct ieee80211_rx_status *rx_status,
81                           struct ieee80211_mgmt *mgmt,
82                           size_t len,
83                           struct ieee802_11_elems *elems,
84                           struct ieee80211_channel *channel,
85                           bool beacon)
86 {
87         struct cfg80211_bss *cbss;
88         struct ieee80211_bss *bss;
89         int clen, srlen;
90         s32 signal = 0;
91
92         if (local->hw.flags & IEEE80211_HW_SIGNAL_DBM)
93                 signal = rx_status->signal * 100;
94         else if (local->hw.flags & IEEE80211_HW_SIGNAL_UNSPEC)
95                 signal = (rx_status->signal * 100) / local->hw.max_signal;
96
97         cbss = cfg80211_inform_bss_frame(local->hw.wiphy, channel,
98                                          mgmt, len, signal, GFP_ATOMIC);
99
100         if (!cbss)
101                 return NULL;
102
103         cbss->free_priv = ieee80211_rx_bss_free;
104         bss = (void *)cbss->priv;
105
106         /* save the ERP value so that it is available at association time */
107         if (elems->erp_info && elems->erp_info_len >= 1) {
108                 bss->erp_value = elems->erp_info[0];
109                 bss->has_erp_value = 1;
110         }
111
112         if (elems->tim) {
113                 struct ieee80211_tim_ie *tim_ie =
114                         (struct ieee80211_tim_ie *)elems->tim;
115                 bss->dtim_period = tim_ie->dtim_period;
116         }
117
118         /* If the beacon had no TIM IE, or it was invalid, use 1 */
119         if (beacon && !bss->dtim_period)
120                 bss->dtim_period = 1;
121
122         /* replace old supported rates if we get new values */
123         srlen = 0;
124         if (elems->supp_rates) {
125                 clen = IEEE80211_MAX_SUPP_RATES;
126                 if (clen > elems->supp_rates_len)
127                         clen = elems->supp_rates_len;
128                 memcpy(bss->supp_rates, elems->supp_rates, clen);
129                 srlen += clen;
130         }
131         if (elems->ext_supp_rates) {
132                 clen = IEEE80211_MAX_SUPP_RATES - srlen;
133                 if (clen > elems->ext_supp_rates_len)
134                         clen = elems->ext_supp_rates_len;
135                 memcpy(bss->supp_rates + srlen, elems->ext_supp_rates, clen);
136                 srlen += clen;
137         }
138         if (srlen)
139                 bss->supp_rates_len = srlen;
140
141         bss->wmm_used = elems->wmm_param || elems->wmm_info;
142         bss->uapsd_supported = is_uapsd_supported(elems);
143
144         if (!beacon)
145                 bss->last_probe_resp = jiffies;
146
147         return bss;
148 }
149
150 ieee80211_rx_result
151 ieee80211_scan_rx(struct ieee80211_sub_if_data *sdata, struct sk_buff *skb)
152 {
153         struct ieee80211_rx_status *rx_status = IEEE80211_SKB_RXCB(skb);
154         struct ieee80211_mgmt *mgmt;
155         struct ieee80211_bss *bss;
156         u8 *elements;
157         struct ieee80211_channel *channel;
158         size_t baselen;
159         int freq;
160         __le16 fc;
161         bool presp, beacon = false;
162         struct ieee802_11_elems elems;
163
164         if (skb->len < 2)
165                 return RX_DROP_UNUSABLE;
166
167         mgmt = (struct ieee80211_mgmt *) skb->data;
168         fc = mgmt->frame_control;
169
170         if (ieee80211_is_ctl(fc))
171                 return RX_CONTINUE;
172
173         if (skb->len < 24)
174                 return RX_CONTINUE;
175
176         presp = ieee80211_is_probe_resp(fc);
177         if (presp) {
178                 /* ignore ProbeResp to foreign address */
179                 if (memcmp(mgmt->da, sdata->vif.addr, ETH_ALEN))
180                         return RX_DROP_MONITOR;
181
182                 presp = true;
183                 elements = mgmt->u.probe_resp.variable;
184                 baselen = offsetof(struct ieee80211_mgmt, u.probe_resp.variable);
185         } else {
186                 beacon = ieee80211_is_beacon(fc);
187                 baselen = offsetof(struct ieee80211_mgmt, u.beacon.variable);
188                 elements = mgmt->u.beacon.variable;
189         }
190
191         if (!presp && !beacon)
192                 return RX_CONTINUE;
193
194         if (baselen > skb->len)
195                 return RX_DROP_MONITOR;
196
197         ieee802_11_parse_elems(elements, skb->len - baselen, &elems);
198
199         if (elems.ds_params && elems.ds_params_len == 1)
200                 freq = ieee80211_channel_to_frequency(elems.ds_params[0],
201                                                       rx_status->band);
202         else
203                 freq = rx_status->freq;
204
205         channel = ieee80211_get_channel(sdata->local->hw.wiphy, freq);
206
207         if (!channel || channel->flags & IEEE80211_CHAN_DISABLED)
208                 return RX_DROP_MONITOR;
209
210         bss = ieee80211_bss_info_update(sdata->local, rx_status,
211                                         mgmt, skb->len, &elems,
212                                         channel, beacon);
213         if (bss)
214                 ieee80211_rx_bss_put(sdata->local, bss);
215
216         if (channel == sdata->local->oper_channel)
217                 return RX_CONTINUE;
218
219         dev_kfree_skb(skb);
220         return RX_QUEUED;
221 }
222
223 /* return false if no more work */
224 static bool ieee80211_prep_hw_scan(struct ieee80211_local *local)
225 {
226         struct cfg80211_scan_request *req = local->scan_req;
227         enum ieee80211_band band;
228         int i, ielen, n_chans;
229
230         do {
231                 if (local->hw_scan_band == IEEE80211_NUM_BANDS)
232                         return false;
233
234                 band = local->hw_scan_band;
235                 n_chans = 0;
236                 for (i = 0; i < req->n_channels; i++) {
237                         if (req->channels[i]->band == band) {
238                                 local->hw_scan_req->channels[n_chans] =
239                                                         req->channels[i];
240                                 n_chans++;
241                         }
242                 }
243
244                 local->hw_scan_band++;
245         } while (!n_chans);
246
247         local->hw_scan_req->n_channels = n_chans;
248
249         ielen = ieee80211_build_preq_ies(local, (u8 *)local->hw_scan_req->ie,
250                                          req->ie, req->ie_len, band,
251                                          req->rates[band], 0);
252         local->hw_scan_req->ie_len = ielen;
253         local->hw_scan_req->no_cck = req->no_cck;
254
255         return true;
256 }
257
258 static void __ieee80211_scan_completed(struct ieee80211_hw *hw, bool aborted,
259                                        bool was_hw_scan)
260 {
261         struct ieee80211_local *local = hw_to_local(hw);
262
263         lockdep_assert_held(&local->mtx);
264
265         /*
266          * It's ok to abort a not-yet-running scan (that
267          * we have one at all will be verified by checking
268          * local->scan_req next), but not to complete it
269          * successfully.
270          */
271         if (WARN_ON(!local->scanning && !aborted))
272                 aborted = true;
273
274         if (WARN_ON(!local->scan_req))
275                 return;
276
277         if (was_hw_scan && !aborted && ieee80211_prep_hw_scan(local)) {
278                 int rc = drv_hw_scan(local, local->scan_sdata, local->hw_scan_req);
279                 if (rc == 0)
280                         return;
281         }
282
283         kfree(local->hw_scan_req);
284         local->hw_scan_req = NULL;
285
286         if (local->scan_req != local->int_scan_req)
287                 cfg80211_scan_done(local->scan_req, aborted);
288         local->scan_req = NULL;
289         local->scan_sdata = NULL;
290
291         local->scanning = 0;
292         local->scan_channel = NULL;
293
294         /* Set power back to normal operating levels. */
295         ieee80211_hw_config(local, 0);
296
297         if (!was_hw_scan) {
298                 ieee80211_configure_filter(local);
299                 drv_sw_scan_complete(local);
300                 ieee80211_offchannel_return(local, true, true);
301         }
302
303         ieee80211_recalc_idle(local);
304
305         ieee80211_mlme_notify_scan_completed(local);
306         ieee80211_ibss_notify_scan_completed(local);
307         ieee80211_mesh_notify_scan_completed(local);
308         ieee80211_queue_work(&local->hw, &local->work_work);
309 }
310
311 void ieee80211_scan_completed(struct ieee80211_hw *hw, bool aborted)
312 {
313         struct ieee80211_local *local = hw_to_local(hw);
314
315         trace_api_scan_completed(local, aborted);
316
317         set_bit(SCAN_COMPLETED, &local->scanning);
318         if (aborted)
319                 set_bit(SCAN_ABORTED, &local->scanning);
320         ieee80211_queue_delayed_work(&local->hw, &local->scan_work, 0);
321 }
322 EXPORT_SYMBOL(ieee80211_scan_completed);
323
324 static int ieee80211_start_sw_scan(struct ieee80211_local *local)
325 {
326         /*
327          * Hardware/driver doesn't support hw_scan, so use software
328          * scanning instead. First send a nullfunc frame with power save
329          * bit on so that AP will buffer the frames for us while we are not
330          * listening, then send probe requests to each channel and wait for
331          * the responses. After all channels are scanned, tune back to the
332          * original channel and send a nullfunc frame with power save bit
333          * off to trigger the AP to send us all the buffered frames.
334          *
335          * Note that while local->sw_scanning is true everything else but
336          * nullfunc frames and probe requests will be dropped in
337          * ieee80211_tx_h_check_assoc().
338          */
339         drv_sw_scan_start(local);
340
341         local->leave_oper_channel_time = 0;
342         local->next_scan_state = SCAN_DECISION;
343         local->scan_channel_idx = 0;
344
345         ieee80211_offchannel_stop_vifs(local, true);
346
347         ieee80211_configure_filter(local);
348
349         /* We need to set power level at maximum rate for scanning. */
350         ieee80211_hw_config(local, 0);
351
352         ieee80211_queue_delayed_work(&local->hw,
353                                      &local->scan_work, 0);
354
355         return 0;
356 }
357
358
359 static int __ieee80211_start_scan(struct ieee80211_sub_if_data *sdata,
360                                   struct cfg80211_scan_request *req)
361 {
362         struct ieee80211_local *local = sdata->local;
363         int rc;
364
365         lockdep_assert_held(&local->mtx);
366
367         if (local->scan_req)
368                 return -EBUSY;
369
370         if (!list_empty(&local->work_list)) {
371                 /* wait for the work to finish/time out */
372                 local->scan_req = req;
373                 local->scan_sdata = sdata;
374                 return 0;
375         }
376
377         if (local->ops->hw_scan) {
378                 u8 *ies;
379
380                 local->hw_scan_req = kmalloc(
381                                 sizeof(*local->hw_scan_req) +
382                                 req->n_channels * sizeof(req->channels[0]) +
383                                 2 + IEEE80211_MAX_SSID_LEN + local->scan_ies_len +
384                                 req->ie_len, GFP_KERNEL);
385                 if (!local->hw_scan_req)
386                         return -ENOMEM;
387
388                 local->hw_scan_req->ssids = req->ssids;
389                 local->hw_scan_req->n_ssids = req->n_ssids;
390                 ies = (u8 *)local->hw_scan_req +
391                         sizeof(*local->hw_scan_req) +
392                         req->n_channels * sizeof(req->channels[0]);
393                 local->hw_scan_req->ie = ies;
394
395                 local->hw_scan_band = 0;
396
397                 /*
398                  * After allocating local->hw_scan_req, we must
399                  * go through until ieee80211_prep_hw_scan(), so
400                  * anything that might be changed here and leave
401                  * this function early must not go after this
402                  * allocation.
403                  */
404         }
405
406         local->scan_req = req;
407         local->scan_sdata = sdata;
408
409         if (local->ops->hw_scan)
410                 __set_bit(SCAN_HW_SCANNING, &local->scanning);
411         else
412                 __set_bit(SCAN_SW_SCANNING, &local->scanning);
413
414         ieee80211_recalc_idle(local);
415
416         if (local->ops->hw_scan) {
417                 WARN_ON(!ieee80211_prep_hw_scan(local));
418                 rc = drv_hw_scan(local, sdata, local->hw_scan_req);
419         } else
420                 rc = ieee80211_start_sw_scan(local);
421
422         if (rc) {
423                 kfree(local->hw_scan_req);
424                 local->hw_scan_req = NULL;
425                 local->scanning = 0;
426
427                 ieee80211_recalc_idle(local);
428
429                 local->scan_req = NULL;
430                 local->scan_sdata = NULL;
431         }
432
433         return rc;
434 }
435
436 static unsigned long
437 ieee80211_scan_get_channel_time(struct ieee80211_channel *chan)
438 {
439         /*
440          * TODO: channel switching also consumes quite some time,
441          * add that delay as well to get a better estimation
442          */
443         if (chan->flags & IEEE80211_CHAN_PASSIVE_SCAN)
444                 return IEEE80211_PASSIVE_CHANNEL_TIME;
445         return IEEE80211_PROBE_DELAY + IEEE80211_CHANNEL_TIME;
446 }
447
448 static void ieee80211_scan_state_decision(struct ieee80211_local *local,
449                                           unsigned long *next_delay)
450 {
451         bool associated = false;
452         bool tx_empty = true;
453         bool bad_latency;
454         bool listen_int_exceeded;
455         unsigned long min_beacon_int = 0;
456         struct ieee80211_sub_if_data *sdata;
457         struct ieee80211_channel *next_chan;
458
459         /*
460          * check if at least one STA interface is associated,
461          * check if at least one STA interface has pending tx frames
462          * and grab the lowest used beacon interval
463          */
464         mutex_lock(&local->iflist_mtx);
465         list_for_each_entry(sdata, &local->interfaces, list) {
466                 if (!ieee80211_sdata_running(sdata))
467                         continue;
468
469                 if (sdata->vif.type == NL80211_IFTYPE_STATION) {
470                         if (sdata->u.mgd.associated) {
471                                 associated = true;
472
473                                 if (sdata->vif.bss_conf.beacon_int <
474                                     min_beacon_int || min_beacon_int == 0)
475                                         min_beacon_int =
476                                                 sdata->vif.bss_conf.beacon_int;
477
478                                 if (!qdisc_all_tx_empty(sdata->dev)) {
479                                         tx_empty = false;
480                                         break;
481                                 }
482                         }
483                 }
484         }
485         mutex_unlock(&local->iflist_mtx);
486
487         next_chan = local->scan_req->channels[local->scan_channel_idx];
488
489         /*
490          * we're currently scanning a different channel, let's
491          * see if we can scan another channel without interfering
492          * with the current traffic situation.
493          *
494          * Since we don't know if the AP has pending frames for us
495          * we can only check for our tx queues and use the current
496          * pm_qos requirements for rx. Hence, if no tx traffic occurs
497          * at all we will scan as many channels in a row as the pm_qos
498          * latency allows us to. Additionally we also check for the
499          * currently negotiated listen interval to prevent losing
500          * frames unnecessarily.
501          *
502          * Otherwise switch back to the operating channel.
503          */
504
505         bad_latency = time_after(jiffies +
506                         ieee80211_scan_get_channel_time(next_chan),
507                         local->leave_oper_channel_time +
508                         usecs_to_jiffies(pm_qos_request(PM_QOS_NETWORK_LATENCY)));
509
510         listen_int_exceeded = time_after(jiffies +
511                         ieee80211_scan_get_channel_time(next_chan),
512                         local->leave_oper_channel_time +
513                         usecs_to_jiffies(min_beacon_int * 1024) *
514                         local->hw.conf.listen_interval);
515
516         if (associated && (!tx_empty || bad_latency || listen_int_exceeded))
517                 local->next_scan_state = SCAN_SUSPEND;
518         else
519                 local->next_scan_state = SCAN_SET_CHANNEL;
520
521         *next_delay = 0;
522 }
523
524 static void ieee80211_scan_state_set_channel(struct ieee80211_local *local,
525                                              unsigned long *next_delay)
526 {
527         int skip;
528         struct ieee80211_channel *chan;
529
530         skip = 0;
531         chan = local->scan_req->channels[local->scan_channel_idx];
532
533         local->scan_channel = chan;
534
535         if (ieee80211_hw_config(local, IEEE80211_CONF_CHANGE_CHANNEL))
536                 skip = 1;
537
538         /* advance state machine to next channel/band */
539         local->scan_channel_idx++;
540
541         if (skip) {
542                 /* if we skip this channel return to the decision state */
543                 local->next_scan_state = SCAN_DECISION;
544                 return;
545         }
546
547         /*
548          * Probe delay is used to update the NAV, cf. 11.1.3.2.2
549          * (which unfortunately doesn't say _why_ step a) is done,
550          * but it waits for the probe delay or until a frame is
551          * received - and the received frame would update the NAV).
552          * For now, we do not support waiting until a frame is
553          * received.
554          *
555          * In any case, it is not necessary for a passive scan.
556          */
557         if (chan->flags & IEEE80211_CHAN_PASSIVE_SCAN ||
558             !local->scan_req->n_ssids) {
559                 *next_delay = IEEE80211_PASSIVE_CHANNEL_TIME;
560                 local->next_scan_state = SCAN_DECISION;
561                 return;
562         }
563
564         /* active scan, send probes */
565         *next_delay = IEEE80211_PROBE_DELAY;
566         local->next_scan_state = SCAN_SEND_PROBE;
567 }
568
569 static void ieee80211_scan_state_send_probe(struct ieee80211_local *local,
570                                             unsigned long *next_delay)
571 {
572         int i;
573         struct ieee80211_sub_if_data *sdata = local->scan_sdata;
574         enum ieee80211_band band = local->hw.conf.channel->band;
575
576         for (i = 0; i < local->scan_req->n_ssids; i++)
577                 ieee80211_send_probe_req(
578                         sdata, NULL,
579                         local->scan_req->ssids[i].ssid,
580                         local->scan_req->ssids[i].ssid_len,
581                         local->scan_req->ie, local->scan_req->ie_len,
582                         local->scan_req->rates[band], false,
583                         local->scan_req->no_cck);
584
585         /*
586          * After sending probe requests, wait for probe responses
587          * on the channel.
588          */
589         *next_delay = IEEE80211_CHANNEL_TIME;
590         local->next_scan_state = SCAN_DECISION;
591 }
592
593 static void ieee80211_scan_state_suspend(struct ieee80211_local *local,
594                                          unsigned long *next_delay)
595 {
596         /* switch back to the operating channel */
597         local->scan_channel = NULL;
598         ieee80211_hw_config(local, IEEE80211_CONF_CHANGE_CHANNEL);
599
600         /*
601          * Re-enable vifs and beaconing.  Leave PS
602          * in off-channel state..will put that back
603          * on-channel at the end of scanning.
604          */
605         ieee80211_offchannel_return(local, true, false);
606
607         *next_delay = HZ / 5;
608         /* afterwards, resume scan & go to next channel */
609         local->next_scan_state = SCAN_RESUME;
610 }
611
612 static void ieee80211_scan_state_resume(struct ieee80211_local *local,
613                                         unsigned long *next_delay)
614 {
615         /* PS already is in off-channel mode */
616         ieee80211_offchannel_stop_vifs(local, false);
617
618         if (local->ops->flush) {
619                 drv_flush(local, false);
620                 *next_delay = 0;
621         } else
622                 *next_delay = HZ / 10;
623
624         /* remember when we left the operating channel */
625         local->leave_oper_channel_time = jiffies;
626
627         /* advance to the next channel to be scanned */
628         local->next_scan_state = SCAN_DECISION;
629 }
630
631 void ieee80211_scan_work(struct work_struct *work)
632 {
633         struct ieee80211_local *local =
634                 container_of(work, struct ieee80211_local, scan_work.work);
635         struct ieee80211_sub_if_data *sdata;
636         unsigned long next_delay = 0;
637         bool aborted, hw_scan;
638
639         mutex_lock(&local->mtx);
640
641         sdata = local->scan_sdata;
642
643         if (test_and_clear_bit(SCAN_COMPLETED, &local->scanning)) {
644                 aborted = test_and_clear_bit(SCAN_ABORTED, &local->scanning);
645                 goto out_complete;
646         }
647
648         if (!sdata || !local->scan_req)
649                 goto out;
650
651         if (local->scan_req && !local->scanning) {
652                 struct cfg80211_scan_request *req = local->scan_req;
653                 int rc;
654
655                 local->scan_req = NULL;
656                 local->scan_sdata = NULL;
657
658                 rc = __ieee80211_start_scan(sdata, req);
659                 if (rc) {
660                         /* need to complete scan in cfg80211 */
661                         local->scan_req = req;
662                         aborted = true;
663                         goto out_complete;
664                 } else
665                         goto out;
666         }
667
668         /*
669          * Avoid re-scheduling when the sdata is going away.
670          */
671         if (!ieee80211_sdata_running(sdata)) {
672                 aborted = true;
673                 goto out_complete;
674         }
675
676         /*
677          * as long as no delay is required advance immediately
678          * without scheduling a new work
679          */
680         do {
681                 if (!ieee80211_sdata_running(sdata)) {
682                         aborted = true;
683                         goto out_complete;
684                 }
685
686                 switch (local->next_scan_state) {
687                 case SCAN_DECISION:
688                         /* if no more bands/channels left, complete scan */
689                         if (local->scan_channel_idx >= local->scan_req->n_channels) {
690                                 aborted = false;
691                                 goto out_complete;
692                         }
693                         ieee80211_scan_state_decision(local, &next_delay);
694                         break;
695                 case SCAN_SET_CHANNEL:
696                         ieee80211_scan_state_set_channel(local, &next_delay);
697                         break;
698                 case SCAN_SEND_PROBE:
699                         ieee80211_scan_state_send_probe(local, &next_delay);
700                         break;
701                 case SCAN_SUSPEND:
702                         ieee80211_scan_state_suspend(local, &next_delay);
703                         break;
704                 case SCAN_RESUME:
705                         ieee80211_scan_state_resume(local, &next_delay);
706                         break;
707                 }
708         } while (next_delay == 0);
709
710         ieee80211_queue_delayed_work(&local->hw, &local->scan_work, next_delay);
711         goto out;
712
713 out_complete:
714         hw_scan = test_bit(SCAN_HW_SCANNING, &local->scanning);
715         __ieee80211_scan_completed(&local->hw, aborted, hw_scan);
716 out:
717         mutex_unlock(&local->mtx);
718 }
719
720 int ieee80211_request_scan(struct ieee80211_sub_if_data *sdata,
721                            struct cfg80211_scan_request *req)
722 {
723         int res;
724
725         mutex_lock(&sdata->local->mtx);
726         res = __ieee80211_start_scan(sdata, req);
727         mutex_unlock(&sdata->local->mtx);
728
729         return res;
730 }
731
732 int ieee80211_request_internal_scan(struct ieee80211_sub_if_data *sdata,
733                                     const u8 *ssid, u8 ssid_len,
734                                     struct ieee80211_channel *chan)
735 {
736         struct ieee80211_local *local = sdata->local;
737         int ret = -EBUSY;
738         enum ieee80211_band band;
739
740         mutex_lock(&local->mtx);
741
742         /* busy scanning */
743         if (local->scan_req)
744                 goto unlock;
745
746         /* fill internal scan request */
747         if (!chan) {
748                 int i, nchan = 0;
749
750                 for (band = 0; band < IEEE80211_NUM_BANDS; band++) {
751                         if (!local->hw.wiphy->bands[band])
752                                 continue;
753                         for (i = 0;
754                              i < local->hw.wiphy->bands[band]->n_channels;
755                              i++) {
756                                 local->int_scan_req->channels[nchan] =
757                                     &local->hw.wiphy->bands[band]->channels[i];
758                                 nchan++;
759                         }
760                 }
761
762                 local->int_scan_req->n_channels = nchan;
763         } else {
764                 local->int_scan_req->channels[0] = chan;
765                 local->int_scan_req->n_channels = 1;
766         }
767
768         local->int_scan_req->ssids = &local->scan_ssid;
769         local->int_scan_req->n_ssids = 1;
770         memcpy(local->int_scan_req->ssids[0].ssid, ssid, IEEE80211_MAX_SSID_LEN);
771         local->int_scan_req->ssids[0].ssid_len = ssid_len;
772
773         ret = __ieee80211_start_scan(sdata, sdata->local->int_scan_req);
774  unlock:
775         mutex_unlock(&local->mtx);
776         return ret;
777 }
778
779 /*
780  * Only call this function when a scan can't be queued -- under RTNL.
781  */
782 void ieee80211_scan_cancel(struct ieee80211_local *local)
783 {
784         /*
785          * We are canceling software scan, or deferred scan that was not
786          * yet really started (see __ieee80211_start_scan ).
787          *
788          * Regarding hardware scan:
789          * - we can not call  __ieee80211_scan_completed() as when
790          *   SCAN_HW_SCANNING bit is set this function change
791          *   local->hw_scan_req to operate on 5G band, what race with
792          *   driver which can use local->hw_scan_req
793          *
794          * - we can not cancel scan_work since driver can schedule it
795          *   by ieee80211_scan_completed(..., true) to finish scan
796          *
797          * Hence we only call the cancel_hw_scan() callback, but the low-level
798          * driver is still responsible for calling ieee80211_scan_completed()
799          * after the scan was completed/aborted.
800          */
801
802         mutex_lock(&local->mtx);
803         if (!local->scan_req)
804                 goto out;
805
806         if (test_bit(SCAN_HW_SCANNING, &local->scanning)) {
807                 if (local->ops->cancel_hw_scan)
808                         drv_cancel_hw_scan(local, local->scan_sdata);
809                 goto out;
810         }
811
812         /*
813          * If the work is currently running, it must be blocked on
814          * the mutex, but we'll set scan_sdata = NULL and it'll
815          * simply exit once it acquires the mutex.
816          */
817         cancel_delayed_work(&local->scan_work);
818         /* and clean up */
819         __ieee80211_scan_completed(&local->hw, true, false);
820 out:
821         mutex_unlock(&local->mtx);
822 }
823
824 int ieee80211_request_sched_scan_start(struct ieee80211_sub_if_data *sdata,
825                                        struct cfg80211_sched_scan_request *req)
826 {
827         struct ieee80211_local *local = sdata->local;
828         int ret, i;
829
830         mutex_lock(&sdata->local->mtx);
831
832         if (local->sched_scanning) {
833                 ret = -EBUSY;
834                 goto out;
835         }
836
837         if (!local->ops->sched_scan_start) {
838                 ret = -ENOTSUPP;
839                 goto out;
840         }
841
842         for (i = 0; i < IEEE80211_NUM_BANDS; i++) {
843                 local->sched_scan_ies.ie[i] = kzalloc(2 +
844                                                       IEEE80211_MAX_SSID_LEN +
845                                                       local->scan_ies_len +
846                                                       req->ie_len,
847                                                       GFP_KERNEL);
848                 if (!local->sched_scan_ies.ie[i]) {
849                         ret = -ENOMEM;
850                         goto out_free;
851                 }
852
853                 local->sched_scan_ies.len[i] =
854                         ieee80211_build_preq_ies(local,
855                                                  local->sched_scan_ies.ie[i],
856                                                  req->ie, req->ie_len, i,
857                                                  (u32) -1, 0);
858         }
859
860         ret = drv_sched_scan_start(local, sdata, req,
861                                    &local->sched_scan_ies);
862         if (ret == 0) {
863                 local->sched_scanning = true;
864                 goto out;
865         }
866
867 out_free:
868         while (i > 0)
869                 kfree(local->sched_scan_ies.ie[--i]);
870 out:
871         mutex_unlock(&sdata->local->mtx);
872         return ret;
873 }
874
875 int ieee80211_request_sched_scan_stop(struct ieee80211_sub_if_data *sdata)
876 {
877         struct ieee80211_local *local = sdata->local;
878         int ret = 0, i;
879
880         mutex_lock(&sdata->local->mtx);
881
882         if (!local->ops->sched_scan_stop) {
883                 ret = -ENOTSUPP;
884                 goto out;
885         }
886
887         if (local->sched_scanning) {
888                 for (i = 0; i < IEEE80211_NUM_BANDS; i++)
889                         kfree(local->sched_scan_ies.ie[i]);
890
891                 drv_sched_scan_stop(local, sdata);
892                 local->sched_scanning = false;
893         }
894 out:
895         mutex_unlock(&sdata->local->mtx);
896
897         return ret;
898 }
899
900 void ieee80211_sched_scan_results(struct ieee80211_hw *hw)
901 {
902         struct ieee80211_local *local = hw_to_local(hw);
903
904         trace_api_sched_scan_results(local);
905
906         cfg80211_sched_scan_results(hw->wiphy);
907 }
908 EXPORT_SYMBOL(ieee80211_sched_scan_results);
909
910 void ieee80211_sched_scan_stopped_work(struct work_struct *work)
911 {
912         struct ieee80211_local *local =
913                 container_of(work, struct ieee80211_local,
914                              sched_scan_stopped_work);
915         int i;
916
917         mutex_lock(&local->mtx);
918
919         if (!local->sched_scanning) {
920                 mutex_unlock(&local->mtx);
921                 return;
922         }
923
924         for (i = 0; i < IEEE80211_NUM_BANDS; i++)
925                 kfree(local->sched_scan_ies.ie[i]);
926
927         local->sched_scanning = false;
928
929         mutex_unlock(&local->mtx);
930
931         cfg80211_sched_scan_stopped(local->hw.wiphy);
932 }
933
934 void ieee80211_sched_scan_stopped(struct ieee80211_hw *hw)
935 {
936         struct ieee80211_local *local = hw_to_local(hw);
937
938         trace_api_sched_scan_stopped(local);
939
940         ieee80211_queue_work(&local->hw, &local->sched_scan_stopped_work);
941 }
942 EXPORT_SYMBOL(ieee80211_sched_scan_stopped);