99b103921a4befecdaa8d95a1391d3f040479fb1
[linux-3.10.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/etherdevice.h>
17 #include <linux/rtnetlink.h>
18 #include <linux/pm_qos.h>
19 #include <net/sch_generic.h>
20 #include <linux/slab.h>
21 #include <linux/export.h>
22 #include <net/mac80211.h>
23
24 #include "ieee80211_i.h"
25 #include "driver-ops.h"
26 #include "mesh.h"
27
28 #define IEEE80211_PROBE_DELAY (HZ / 33)
29 #define IEEE80211_CHANNEL_TIME (HZ / 33)
30 #define IEEE80211_PASSIVE_CHANNEL_TIME (HZ / 9)
31
32 void ieee80211_rx_bss_put(struct ieee80211_local *local,
33                           struct ieee80211_bss *bss)
34 {
35         if (!bss)
36                 return;
37         cfg80211_put_bss(local->hw.wiphy,
38                          container_of((void *)bss, struct cfg80211_bss, priv));
39 }
40
41 static bool is_uapsd_supported(struct ieee802_11_elems *elems)
42 {
43         u8 qos_info;
44
45         if (elems->wmm_info && elems->wmm_info_len == 7
46             && elems->wmm_info[5] == 1)
47                 qos_info = elems->wmm_info[6];
48         else if (elems->wmm_param && elems->wmm_param_len == 24
49                  && elems->wmm_param[5] == 1)
50                 qos_info = elems->wmm_param[6];
51         else
52                 /* no valid wmm information or parameter element found */
53                 return false;
54
55         return qos_info & IEEE80211_WMM_IE_AP_QOSINFO_UAPSD;
56 }
57
58 struct ieee80211_bss *
59 ieee80211_bss_info_update(struct ieee80211_local *local,
60                           struct ieee80211_rx_status *rx_status,
61                           struct ieee80211_mgmt *mgmt, size_t len,
62                           struct ieee802_11_elems *elems,
63                           struct ieee80211_channel *channel)
64 {
65         bool beacon = ieee80211_is_beacon(mgmt->frame_control);
66         struct cfg80211_bss *cbss;
67         struct ieee80211_bss *bss;
68         int clen, srlen;
69         s32 signal = 0;
70
71         if (local->hw.flags & IEEE80211_HW_SIGNAL_DBM)
72                 signal = rx_status->signal * 100;
73         else if (local->hw.flags & IEEE80211_HW_SIGNAL_UNSPEC)
74                 signal = (rx_status->signal * 100) / local->hw.max_signal;
75
76         cbss = cfg80211_inform_bss_frame(local->hw.wiphy, channel,
77                                          mgmt, len, signal, GFP_ATOMIC);
78         if (!cbss)
79                 return NULL;
80
81         bss = (void *)cbss->priv;
82
83         if (beacon)
84                 bss->device_ts_beacon = rx_status->device_timestamp;
85         else
86                 bss->device_ts_presp = rx_status->device_timestamp;
87
88         if (elems->parse_error) {
89                 if (beacon)
90                         bss->corrupt_data |= IEEE80211_BSS_CORRUPT_BEACON;
91                 else
92                         bss->corrupt_data |= IEEE80211_BSS_CORRUPT_PROBE_RESP;
93         } else {
94                 if (beacon)
95                         bss->corrupt_data &= ~IEEE80211_BSS_CORRUPT_BEACON;
96                 else
97                         bss->corrupt_data &= ~IEEE80211_BSS_CORRUPT_PROBE_RESP;
98         }
99
100         /* save the ERP value so that it is available at association time */
101         if (elems->erp_info && (!elems->parse_error ||
102                                 !(bss->valid_data & IEEE80211_BSS_VALID_ERP))) {
103                 bss->erp_value = elems->erp_info[0];
104                 bss->has_erp_value = true;
105                 if (!elems->parse_error)
106                         bss->valid_data |= IEEE80211_BSS_VALID_ERP;
107         }
108
109         /* replace old supported rates if we get new values */
110         if (!elems->parse_error ||
111             !(bss->valid_data & IEEE80211_BSS_VALID_RATES)) {
112                 srlen = 0;
113                 if (elems->supp_rates) {
114                         clen = IEEE80211_MAX_SUPP_RATES;
115                         if (clen > elems->supp_rates_len)
116                                 clen = elems->supp_rates_len;
117                         memcpy(bss->supp_rates, elems->supp_rates, clen);
118                         srlen += clen;
119                 }
120                 if (elems->ext_supp_rates) {
121                         clen = IEEE80211_MAX_SUPP_RATES - srlen;
122                         if (clen > elems->ext_supp_rates_len)
123                                 clen = elems->ext_supp_rates_len;
124                         memcpy(bss->supp_rates + srlen, elems->ext_supp_rates,
125                                clen);
126                         srlen += clen;
127                 }
128                 if (srlen) {
129                         bss->supp_rates_len = srlen;
130                         if (!elems->parse_error)
131                                 bss->valid_data |= IEEE80211_BSS_VALID_RATES;
132                 }
133         }
134
135         if (!elems->parse_error ||
136             !(bss->valid_data & IEEE80211_BSS_VALID_WMM)) {
137                 bss->wmm_used = elems->wmm_param || elems->wmm_info;
138                 bss->uapsd_supported = is_uapsd_supported(elems);
139                 if (!elems->parse_error)
140                         bss->valid_data |= IEEE80211_BSS_VALID_WMM;
141         }
142
143         return bss;
144 }
145
146 void ieee80211_scan_rx(struct ieee80211_local *local, struct sk_buff *skb)
147 {
148         struct ieee80211_rx_status *rx_status = IEEE80211_SKB_RXCB(skb);
149         struct ieee80211_sub_if_data *sdata1, *sdata2;
150         struct ieee80211_mgmt *mgmt = (void *)skb->data;
151         struct ieee80211_bss *bss;
152         u8 *elements;
153         struct ieee80211_channel *channel;
154         size_t baselen;
155         struct ieee802_11_elems elems;
156
157         if (skb->len < 24 ||
158             (!ieee80211_is_probe_resp(mgmt->frame_control) &&
159              !ieee80211_is_beacon(mgmt->frame_control)))
160                 return;
161
162         sdata1 = rcu_dereference(local->scan_sdata);
163         sdata2 = rcu_dereference(local->sched_scan_sdata);
164
165         if (likely(!sdata1 && !sdata2))
166                 return;
167
168         if (ieee80211_is_probe_resp(mgmt->frame_control)) {
169                 /* ignore ProbeResp to foreign address */
170                 if ((!sdata1 || !ether_addr_equal(mgmt->da, sdata1->vif.addr)) &&
171                     (!sdata2 || !ether_addr_equal(mgmt->da, sdata2->vif.addr)))
172                         return;
173
174                 elements = mgmt->u.probe_resp.variable;
175                 baselen = offsetof(struct ieee80211_mgmt, u.probe_resp.variable);
176         } else {
177                 baselen = offsetof(struct ieee80211_mgmt, u.beacon.variable);
178                 elements = mgmt->u.beacon.variable;
179         }
180
181         if (baselen > skb->len)
182                 return;
183
184         ieee802_11_parse_elems(elements, skb->len - baselen, false, &elems);
185
186         channel = ieee80211_get_channel(local->hw.wiphy, rx_status->freq);
187
188         if (!channel || channel->flags & IEEE80211_CHAN_DISABLED)
189                 return;
190
191         bss = ieee80211_bss_info_update(local, rx_status,
192                                         mgmt, skb->len, &elems,
193                                         channel);
194         if (bss)
195                 ieee80211_rx_bss_put(local, bss);
196 }
197
198 /* return false if no more work */
199 static bool ieee80211_prep_hw_scan(struct ieee80211_local *local)
200 {
201         struct cfg80211_scan_request *req = local->scan_req;
202         enum ieee80211_band band;
203         int i, ielen, n_chans;
204
205         do {
206                 if (local->hw_scan_band == IEEE80211_NUM_BANDS)
207                         return false;
208
209                 band = local->hw_scan_band;
210                 n_chans = 0;
211                 for (i = 0; i < req->n_channels; i++) {
212                         if (req->channels[i]->band == band) {
213                                 local->hw_scan_req->channels[n_chans] =
214                                                         req->channels[i];
215                                 n_chans++;
216                         }
217                 }
218
219                 local->hw_scan_band++;
220         } while (!n_chans);
221
222         local->hw_scan_req->n_channels = n_chans;
223
224         ielen = ieee80211_build_preq_ies(local, (u8 *)local->hw_scan_req->ie,
225                                          local->hw_scan_ies_bufsize,
226                                          req->ie, req->ie_len, band,
227                                          req->rates[band], 0);
228         local->hw_scan_req->ie_len = ielen;
229         local->hw_scan_req->no_cck = req->no_cck;
230
231         return true;
232 }
233
234 static void __ieee80211_scan_completed(struct ieee80211_hw *hw, bool aborted,
235                                        bool was_hw_scan)
236 {
237         struct ieee80211_local *local = hw_to_local(hw);
238
239         lockdep_assert_held(&local->mtx);
240
241         /*
242          * It's ok to abort a not-yet-running scan (that
243          * we have one at all will be verified by checking
244          * local->scan_req next), but not to complete it
245          * successfully.
246          */
247         if (WARN_ON(!local->scanning && !aborted))
248                 aborted = true;
249
250         if (WARN_ON(!local->scan_req))
251                 return;
252
253         if (was_hw_scan && !aborted && ieee80211_prep_hw_scan(local)) {
254                 int rc;
255
256                 rc = drv_hw_scan(local,
257                         rcu_dereference_protected(local->scan_sdata,
258                                                   lockdep_is_held(&local->mtx)),
259                         local->hw_scan_req);
260
261                 if (rc == 0)
262                         return;
263         }
264
265         kfree(local->hw_scan_req);
266         local->hw_scan_req = NULL;
267
268         if (local->scan_req != local->int_scan_req)
269                 cfg80211_scan_done(local->scan_req, aborted);
270         local->scan_req = NULL;
271         rcu_assign_pointer(local->scan_sdata, NULL);
272
273         local->scanning = 0;
274         local->scan_channel = NULL;
275
276         /* Set power back to normal operating levels. */
277         ieee80211_hw_config(local, 0);
278
279         if (!was_hw_scan) {
280                 ieee80211_configure_filter(local);
281                 drv_sw_scan_complete(local);
282                 ieee80211_offchannel_return(local);
283         }
284
285         ieee80211_recalc_idle(local);
286
287         ieee80211_mlme_notify_scan_completed(local);
288         ieee80211_ibss_notify_scan_completed(local);
289         ieee80211_mesh_notify_scan_completed(local);
290         ieee80211_start_next_roc(local);
291 }
292
293 void ieee80211_scan_completed(struct ieee80211_hw *hw, bool aborted)
294 {
295         struct ieee80211_local *local = hw_to_local(hw);
296
297         trace_api_scan_completed(local, aborted);
298
299         set_bit(SCAN_COMPLETED, &local->scanning);
300         if (aborted)
301                 set_bit(SCAN_ABORTED, &local->scanning);
302         ieee80211_queue_delayed_work(&local->hw, &local->scan_work, 0);
303 }
304 EXPORT_SYMBOL(ieee80211_scan_completed);
305
306 static int ieee80211_start_sw_scan(struct ieee80211_local *local)
307 {
308         /* Software scan is not supported in multi-channel cases */
309         if (local->use_chanctx)
310                 return -EOPNOTSUPP;
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         local->leave_oper_channel_time = jiffies;
328         local->next_scan_state = SCAN_DECISION;
329         local->scan_channel_idx = 0;
330
331         ieee80211_offchannel_stop_vifs(local);
332
333         /* ensure nullfunc is transmitted before leaving operating channel */
334         ieee80211_flush_queues(local, NULL);
335
336         ieee80211_configure_filter(local);
337
338         /* We need to set power level at maximum rate for scanning. */
339         ieee80211_hw_config(local, 0);
340
341         ieee80211_queue_delayed_work(&local->hw,
342                                      &local->scan_work, 0);
343
344         return 0;
345 }
346
347 static bool ieee80211_can_scan(struct ieee80211_local *local,
348                                struct ieee80211_sub_if_data *sdata)
349 {
350         if (local->radar_detect_enabled)
351                 return false;
352
353         if (!list_empty(&local->roc_list))
354                 return false;
355
356         if (sdata->vif.type == NL80211_IFTYPE_STATION &&
357             sdata->u.mgd.flags & (IEEE80211_STA_BEACON_POLL |
358                                   IEEE80211_STA_CONNECTION_POLL))
359                 return false;
360
361         return true;
362 }
363
364 void ieee80211_run_deferred_scan(struct ieee80211_local *local)
365 {
366         lockdep_assert_held(&local->mtx);
367
368         if (!local->scan_req || local->scanning)
369                 return;
370
371         if (!ieee80211_can_scan(local,
372                                 rcu_dereference_protected(
373                                         local->scan_sdata,
374                                         lockdep_is_held(&local->mtx))))
375                 return;
376
377         ieee80211_queue_delayed_work(&local->hw, &local->scan_work,
378                                      round_jiffies_relative(0));
379 }
380
381 static void ieee80211_scan_state_send_probe(struct ieee80211_local *local,
382                                             unsigned long *next_delay)
383 {
384         int i;
385         struct ieee80211_sub_if_data *sdata;
386         enum ieee80211_band band = local->hw.conf.chandef.chan->band;
387         u32 tx_flags;
388
389         tx_flags = IEEE80211_TX_INTFL_OFFCHAN_TX_OK;
390         if (local->scan_req->no_cck)
391                 tx_flags |= IEEE80211_TX_CTL_NO_CCK_RATE;
392
393         sdata = rcu_dereference_protected(local->scan_sdata,
394                                           lockdep_is_held(&local->mtx));
395
396         for (i = 0; i < local->scan_req->n_ssids; i++)
397                 ieee80211_send_probe_req(
398                         sdata, NULL,
399                         local->scan_req->ssids[i].ssid,
400                         local->scan_req->ssids[i].ssid_len,
401                         local->scan_req->ie, local->scan_req->ie_len,
402                         local->scan_req->rates[band], false,
403                         tx_flags, local->hw.conf.chandef.chan, true);
404
405         /*
406          * After sending probe requests, wait for probe responses
407          * on the channel.
408          */
409         *next_delay = IEEE80211_CHANNEL_TIME;
410         local->next_scan_state = SCAN_DECISION;
411 }
412
413 static int __ieee80211_start_scan(struct ieee80211_sub_if_data *sdata,
414                                   struct cfg80211_scan_request *req)
415 {
416         struct ieee80211_local *local = sdata->local;
417         int rc;
418
419         lockdep_assert_held(&local->mtx);
420
421         if (local->scan_req)
422                 return -EBUSY;
423
424         if (!ieee80211_can_scan(local, sdata)) {
425                 /* wait for the work to finish/time out */
426                 local->scan_req = req;
427                 rcu_assign_pointer(local->scan_sdata, sdata);
428                 return 0;
429         }
430
431         if (local->ops->hw_scan) {
432                 u8 *ies;
433
434                 local->hw_scan_ies_bufsize = 2 + IEEE80211_MAX_SSID_LEN +
435                                              local->scan_ies_len +
436                                              req->ie_len;
437                 local->hw_scan_req = kmalloc(
438                                 sizeof(*local->hw_scan_req) +
439                                 req->n_channels * sizeof(req->channels[0]) +
440                                 local->hw_scan_ies_bufsize, GFP_KERNEL);
441                 if (!local->hw_scan_req)
442                         return -ENOMEM;
443
444                 local->hw_scan_req->ssids = req->ssids;
445                 local->hw_scan_req->n_ssids = req->n_ssids;
446                 ies = (u8 *)local->hw_scan_req +
447                         sizeof(*local->hw_scan_req) +
448                         req->n_channels * sizeof(req->channels[0]);
449                 local->hw_scan_req->ie = ies;
450                 local->hw_scan_req->flags = req->flags;
451
452                 local->hw_scan_band = 0;
453
454                 /*
455                  * After allocating local->hw_scan_req, we must
456                  * go through until ieee80211_prep_hw_scan(), so
457                  * anything that might be changed here and leave
458                  * this function early must not go after this
459                  * allocation.
460                  */
461         }
462
463         local->scan_req = req;
464         rcu_assign_pointer(local->scan_sdata, sdata);
465
466         if (local->ops->hw_scan) {
467                 __set_bit(SCAN_HW_SCANNING, &local->scanning);
468         } else if ((req->n_channels == 1) &&
469                    (req->channels[0] == local->_oper_chandef.chan)) {
470                 /*
471                  * If we are scanning only on the operating channel
472                  * then we do not need to stop normal activities
473                  */
474                 unsigned long next_delay;
475
476                 __set_bit(SCAN_ONCHANNEL_SCANNING, &local->scanning);
477
478                 ieee80211_recalc_idle(local);
479
480                 /* Notify driver scan is starting, keep order of operations
481                  * same as normal software scan, in case that matters. */
482                 drv_sw_scan_start(local);
483
484                 ieee80211_configure_filter(local); /* accept probe-responses */
485
486                 /* We need to ensure power level is at max for scanning. */
487                 ieee80211_hw_config(local, 0);
488
489                 if ((req->channels[0]->flags &
490                      IEEE80211_CHAN_PASSIVE_SCAN) ||
491                     !local->scan_req->n_ssids) {
492                         next_delay = IEEE80211_PASSIVE_CHANNEL_TIME;
493                 } else {
494                         ieee80211_scan_state_send_probe(local, &next_delay);
495                         next_delay = IEEE80211_CHANNEL_TIME;
496                 }
497
498                 /* Now, just wait a bit and we are all done! */
499                 ieee80211_queue_delayed_work(&local->hw, &local->scan_work,
500                                              next_delay);
501                 return 0;
502         } else {
503                 /* Do normal software scan */
504                 __set_bit(SCAN_SW_SCANNING, &local->scanning);
505         }
506
507         ieee80211_recalc_idle(local);
508
509         if (local->ops->hw_scan) {
510                 WARN_ON(!ieee80211_prep_hw_scan(local));
511                 rc = drv_hw_scan(local, sdata, local->hw_scan_req);
512         } else
513                 rc = ieee80211_start_sw_scan(local);
514
515         if (rc) {
516                 kfree(local->hw_scan_req);
517                 local->hw_scan_req = NULL;
518                 local->scanning = 0;
519
520                 ieee80211_recalc_idle(local);
521
522                 local->scan_req = NULL;
523                 rcu_assign_pointer(local->scan_sdata, NULL);
524         }
525
526         return rc;
527 }
528
529 static unsigned long
530 ieee80211_scan_get_channel_time(struct ieee80211_channel *chan)
531 {
532         /*
533          * TODO: channel switching also consumes quite some time,
534          * add that delay as well to get a better estimation
535          */
536         if (chan->flags & IEEE80211_CHAN_PASSIVE_SCAN)
537                 return IEEE80211_PASSIVE_CHANNEL_TIME;
538         return IEEE80211_PROBE_DELAY + IEEE80211_CHANNEL_TIME;
539 }
540
541 static void ieee80211_scan_state_decision(struct ieee80211_local *local,
542                                           unsigned long *next_delay)
543 {
544         bool associated = false;
545         bool tx_empty = true;
546         bool bad_latency;
547         struct ieee80211_sub_if_data *sdata;
548         struct ieee80211_channel *next_chan;
549         enum mac80211_scan_state next_scan_state;
550
551         /*
552          * check if at least one STA interface is associated,
553          * check if at least one STA interface has pending tx frames
554          * and grab the lowest used beacon interval
555          */
556         mutex_lock(&local->iflist_mtx);
557         list_for_each_entry(sdata, &local->interfaces, list) {
558                 if (!ieee80211_sdata_running(sdata))
559                         continue;
560
561                 if (sdata->vif.type == NL80211_IFTYPE_STATION) {
562                         if (sdata->u.mgd.associated) {
563                                 associated = true;
564
565                                 if (!qdisc_all_tx_empty(sdata->dev)) {
566                                         tx_empty = false;
567                                         break;
568                                 }
569                         }
570                 }
571         }
572         mutex_unlock(&local->iflist_mtx);
573
574         next_chan = local->scan_req->channels[local->scan_channel_idx];
575
576         /*
577          * we're currently scanning a different channel, let's
578          * see if we can scan another channel without interfering
579          * with the current traffic situation.
580          *
581          * Keep good latency, do not stay off-channel more than 125 ms.
582          */
583
584         bad_latency = time_after(jiffies +
585                                  ieee80211_scan_get_channel_time(next_chan),
586                                  local->leave_oper_channel_time + HZ / 8);
587
588         if (associated && !tx_empty) {
589                 if (local->scan_req->flags & NL80211_SCAN_FLAG_LOW_PRIORITY)
590                         next_scan_state = SCAN_ABORT;
591                 else
592                         next_scan_state = SCAN_SUSPEND;
593         } else if (associated && bad_latency) {
594                 next_scan_state = SCAN_SUSPEND;
595         } else {
596                 next_scan_state = SCAN_SET_CHANNEL;
597         }
598
599         local->next_scan_state = next_scan_state;
600
601         *next_delay = 0;
602 }
603
604 static void ieee80211_scan_state_set_channel(struct ieee80211_local *local,
605                                              unsigned long *next_delay)
606 {
607         int skip;
608         struct ieee80211_channel *chan;
609
610         skip = 0;
611         chan = local->scan_req->channels[local->scan_channel_idx];
612
613         local->scan_channel = chan;
614
615         if (ieee80211_hw_config(local, IEEE80211_CONF_CHANGE_CHANNEL))
616                 skip = 1;
617
618         /* advance state machine to next channel/band */
619         local->scan_channel_idx++;
620
621         if (skip) {
622                 /* if we skip this channel return to the decision state */
623                 local->next_scan_state = SCAN_DECISION;
624                 return;
625         }
626
627         /*
628          * Probe delay is used to update the NAV, cf. 11.1.3.2.2
629          * (which unfortunately doesn't say _why_ step a) is done,
630          * but it waits for the probe delay or until a frame is
631          * received - and the received frame would update the NAV).
632          * For now, we do not support waiting until a frame is
633          * received.
634          *
635          * In any case, it is not necessary for a passive scan.
636          */
637         if (chan->flags & IEEE80211_CHAN_PASSIVE_SCAN ||
638             !local->scan_req->n_ssids) {
639                 *next_delay = IEEE80211_PASSIVE_CHANNEL_TIME;
640                 local->next_scan_state = SCAN_DECISION;
641                 return;
642         }
643
644         /* active scan, send probes */
645         *next_delay = IEEE80211_PROBE_DELAY;
646         local->next_scan_state = SCAN_SEND_PROBE;
647 }
648
649 static void ieee80211_scan_state_suspend(struct ieee80211_local *local,
650                                          unsigned long *next_delay)
651 {
652         /* switch back to the operating channel */
653         local->scan_channel = NULL;
654         ieee80211_hw_config(local, IEEE80211_CONF_CHANGE_CHANNEL);
655
656         /* disable PS */
657         ieee80211_offchannel_return(local);
658
659         *next_delay = HZ / 5;
660         /* afterwards, resume scan & go to next channel */
661         local->next_scan_state = SCAN_RESUME;
662 }
663
664 static void ieee80211_scan_state_resume(struct ieee80211_local *local,
665                                         unsigned long *next_delay)
666 {
667         ieee80211_offchannel_stop_vifs(local);
668
669         if (local->ops->flush) {
670                 ieee80211_flush_queues(local, NULL);
671                 *next_delay = 0;
672         } else
673                 *next_delay = HZ / 10;
674
675         /* remember when we left the operating channel */
676         local->leave_oper_channel_time = jiffies;
677
678         /* advance to the next channel to be scanned */
679         local->next_scan_state = SCAN_SET_CHANNEL;
680 }
681
682 void ieee80211_scan_work(struct work_struct *work)
683 {
684         struct ieee80211_local *local =
685                 container_of(work, struct ieee80211_local, scan_work.work);
686         struct ieee80211_sub_if_data *sdata;
687         unsigned long next_delay = 0;
688         bool aborted, hw_scan;
689
690         mutex_lock(&local->mtx);
691
692         sdata = rcu_dereference_protected(local->scan_sdata,
693                                           lockdep_is_held(&local->mtx));
694
695         /* When scanning on-channel, the first-callback means completed. */
696         if (test_bit(SCAN_ONCHANNEL_SCANNING, &local->scanning)) {
697                 aborted = test_and_clear_bit(SCAN_ABORTED, &local->scanning);
698                 goto out_complete;
699         }
700
701         if (test_and_clear_bit(SCAN_COMPLETED, &local->scanning)) {
702                 aborted = test_and_clear_bit(SCAN_ABORTED, &local->scanning);
703                 goto out_complete;
704         }
705
706         if (!sdata || !local->scan_req)
707                 goto out;
708
709         if (local->scan_req && !local->scanning) {
710                 struct cfg80211_scan_request *req = local->scan_req;
711                 int rc;
712
713                 local->scan_req = NULL;
714                 rcu_assign_pointer(local->scan_sdata, NULL);
715
716                 rc = __ieee80211_start_scan(sdata, req);
717                 if (rc) {
718                         /* need to complete scan in cfg80211 */
719                         local->scan_req = req;
720                         aborted = true;
721                         goto out_complete;
722                 } else
723                         goto out;
724         }
725
726         /*
727          * Avoid re-scheduling when the sdata is going away.
728          */
729         if (!ieee80211_sdata_running(sdata)) {
730                 aborted = true;
731                 goto out_complete;
732         }
733
734         /*
735          * as long as no delay is required advance immediately
736          * without scheduling a new work
737          */
738         do {
739                 if (!ieee80211_sdata_running(sdata)) {
740                         aborted = true;
741                         goto out_complete;
742                 }
743
744                 switch (local->next_scan_state) {
745                 case SCAN_DECISION:
746                         /* if no more bands/channels left, complete scan */
747                         if (local->scan_channel_idx >= local->scan_req->n_channels) {
748                                 aborted = false;
749                                 goto out_complete;
750                         }
751                         ieee80211_scan_state_decision(local, &next_delay);
752                         break;
753                 case SCAN_SET_CHANNEL:
754                         ieee80211_scan_state_set_channel(local, &next_delay);
755                         break;
756                 case SCAN_SEND_PROBE:
757                         ieee80211_scan_state_send_probe(local, &next_delay);
758                         break;
759                 case SCAN_SUSPEND:
760                         ieee80211_scan_state_suspend(local, &next_delay);
761                         break;
762                 case SCAN_RESUME:
763                         ieee80211_scan_state_resume(local, &next_delay);
764                         break;
765                 case SCAN_ABORT:
766                         aborted = true;
767                         goto out_complete;
768                 }
769         } while (next_delay == 0);
770
771         ieee80211_queue_delayed_work(&local->hw, &local->scan_work, next_delay);
772         goto out;
773
774 out_complete:
775         hw_scan = test_bit(SCAN_HW_SCANNING, &local->scanning);
776         __ieee80211_scan_completed(&local->hw, aborted, hw_scan);
777 out:
778         mutex_unlock(&local->mtx);
779 }
780
781 int ieee80211_request_scan(struct ieee80211_sub_if_data *sdata,
782                            struct cfg80211_scan_request *req)
783 {
784         int res;
785
786         mutex_lock(&sdata->local->mtx);
787         res = __ieee80211_start_scan(sdata, req);
788         mutex_unlock(&sdata->local->mtx);
789
790         return res;
791 }
792
793 int ieee80211_request_ibss_scan(struct ieee80211_sub_if_data *sdata,
794                                 const u8 *ssid, u8 ssid_len,
795                                 struct ieee80211_channel *chan)
796 {
797         struct ieee80211_local *local = sdata->local;
798         int ret = -EBUSY;
799         enum ieee80211_band band;
800
801         mutex_lock(&local->mtx);
802
803         /* busy scanning */
804         if (local->scan_req)
805                 goto unlock;
806
807         /* fill internal scan request */
808         if (!chan) {
809                 int i, max_n;
810                 int n_ch = 0;
811
812                 for (band = 0; band < IEEE80211_NUM_BANDS; band++) {
813                         if (!local->hw.wiphy->bands[band])
814                                 continue;
815
816                         max_n = local->hw.wiphy->bands[band]->n_channels;
817                         for (i = 0; i < max_n; i++) {
818                                 struct ieee80211_channel *tmp_ch =
819                                     &local->hw.wiphy->bands[band]->channels[i];
820
821                                 if (tmp_ch->flags & (IEEE80211_CHAN_NO_IBSS |
822                                                      IEEE80211_CHAN_DISABLED))
823                                         continue;
824
825                                 local->int_scan_req->channels[n_ch] = tmp_ch;
826                                 n_ch++;
827                         }
828                 }
829
830                 if (WARN_ON_ONCE(n_ch == 0))
831                         goto unlock;
832
833                 local->int_scan_req->n_channels = n_ch;
834         } else {
835                 if (WARN_ON_ONCE(chan->flags & (IEEE80211_CHAN_NO_IBSS |
836                                                 IEEE80211_CHAN_DISABLED)))
837                         goto unlock;
838
839                 local->int_scan_req->channels[0] = chan;
840                 local->int_scan_req->n_channels = 1;
841         }
842
843         local->int_scan_req->ssids = &local->scan_ssid;
844         local->int_scan_req->n_ssids = 1;
845         memcpy(local->int_scan_req->ssids[0].ssid, ssid, IEEE80211_MAX_SSID_LEN);
846         local->int_scan_req->ssids[0].ssid_len = ssid_len;
847
848         ret = __ieee80211_start_scan(sdata, sdata->local->int_scan_req);
849  unlock:
850         mutex_unlock(&local->mtx);
851         return ret;
852 }
853
854 /*
855  * Only call this function when a scan can't be queued -- under RTNL.
856  */
857 void ieee80211_scan_cancel(struct ieee80211_local *local)
858 {
859         /*
860          * We are canceling software scan, or deferred scan that was not
861          * yet really started (see __ieee80211_start_scan ).
862          *
863          * Regarding hardware scan:
864          * - we can not call  __ieee80211_scan_completed() as when
865          *   SCAN_HW_SCANNING bit is set this function change
866          *   local->hw_scan_req to operate on 5G band, what race with
867          *   driver which can use local->hw_scan_req
868          *
869          * - we can not cancel scan_work since driver can schedule it
870          *   by ieee80211_scan_completed(..., true) to finish scan
871          *
872          * Hence we only call the cancel_hw_scan() callback, but the low-level
873          * driver is still responsible for calling ieee80211_scan_completed()
874          * after the scan was completed/aborted.
875          */
876
877         mutex_lock(&local->mtx);
878         if (!local->scan_req)
879                 goto out;
880
881         if (test_bit(SCAN_HW_SCANNING, &local->scanning)) {
882                 if (local->ops->cancel_hw_scan)
883                         drv_cancel_hw_scan(local,
884                                 rcu_dereference_protected(local->scan_sdata,
885                                                 lockdep_is_held(&local->mtx)));
886                 goto out;
887         }
888
889         /*
890          * If the work is currently running, it must be blocked on
891          * the mutex, but we'll set scan_sdata = NULL and it'll
892          * simply exit once it acquires the mutex.
893          */
894         cancel_delayed_work(&local->scan_work);
895         /* and clean up */
896         __ieee80211_scan_completed(&local->hw, true, false);
897 out:
898         mutex_unlock(&local->mtx);
899 }
900
901 int ieee80211_request_sched_scan_start(struct ieee80211_sub_if_data *sdata,
902                                        struct cfg80211_sched_scan_request *req)
903 {
904         struct ieee80211_local *local = sdata->local;
905         struct ieee80211_sched_scan_ies sched_scan_ies = {};
906         int ret, i, iebufsz;
907
908         iebufsz = 2 + IEEE80211_MAX_SSID_LEN +
909                   local->scan_ies_len + req->ie_len;
910
911         mutex_lock(&local->mtx);
912
913         if (rcu_access_pointer(local->sched_scan_sdata)) {
914                 ret = -EBUSY;
915                 goto out;
916         }
917
918         if (!local->ops->sched_scan_start) {
919                 ret = -ENOTSUPP;
920                 goto out;
921         }
922
923         for (i = 0; i < IEEE80211_NUM_BANDS; i++) {
924                 if (!local->hw.wiphy->bands[i])
925                         continue;
926
927                 sched_scan_ies.ie[i] = kzalloc(iebufsz, GFP_KERNEL);
928                 if (!sched_scan_ies.ie[i]) {
929                         ret = -ENOMEM;
930                         goto out_free;
931                 }
932
933                 sched_scan_ies.len[i] =
934                         ieee80211_build_preq_ies(local, sched_scan_ies.ie[i],
935                                                  iebufsz, req->ie, req->ie_len,
936                                                  i, (u32) -1, 0);
937         }
938
939         ret = drv_sched_scan_start(local, sdata, req, &sched_scan_ies);
940         if (ret == 0)
941                 rcu_assign_pointer(local->sched_scan_sdata, sdata);
942
943 out_free:
944         while (i > 0)
945                 kfree(sched_scan_ies.ie[--i]);
946 out:
947         mutex_unlock(&local->mtx);
948         return ret;
949 }
950
951 int ieee80211_request_sched_scan_stop(struct ieee80211_sub_if_data *sdata)
952 {
953         struct ieee80211_local *local = sdata->local;
954         int ret = 0;
955
956         mutex_lock(&local->mtx);
957
958         if (!local->ops->sched_scan_stop) {
959                 ret = -ENOTSUPP;
960                 goto out;
961         }
962
963         if (rcu_access_pointer(local->sched_scan_sdata))
964                 drv_sched_scan_stop(local, sdata);
965
966 out:
967         mutex_unlock(&local->mtx);
968
969         return ret;
970 }
971
972 void ieee80211_sched_scan_results(struct ieee80211_hw *hw)
973 {
974         struct ieee80211_local *local = hw_to_local(hw);
975
976         trace_api_sched_scan_results(local);
977
978         cfg80211_sched_scan_results(hw->wiphy);
979 }
980 EXPORT_SYMBOL(ieee80211_sched_scan_results);
981
982 void ieee80211_sched_scan_stopped_work(struct work_struct *work)
983 {
984         struct ieee80211_local *local =
985                 container_of(work, struct ieee80211_local,
986                              sched_scan_stopped_work);
987
988         mutex_lock(&local->mtx);
989
990         if (!rcu_access_pointer(local->sched_scan_sdata)) {
991                 mutex_unlock(&local->mtx);
992                 return;
993         }
994
995         rcu_assign_pointer(local->sched_scan_sdata, NULL);
996
997         mutex_unlock(&local->mtx);
998
999         cfg80211_sched_scan_stopped(local->hw.wiphy);
1000 }
1001
1002 void ieee80211_sched_scan_stopped(struct ieee80211_hw *hw)
1003 {
1004         struct ieee80211_local *local = hw_to_local(hw);
1005
1006         trace_api_sched_scan_stopped(local);
1007
1008         ieee80211_queue_work(&local->hw, &local->sched_scan_stopped_work);
1009 }
1010 EXPORT_SYMBOL(ieee80211_sched_scan_stopped);