Merge branch 'master' of git://git.kernel.org/pub/scm/linux/kernel/git/linville/wirel...
[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 / 8)
31
32 static void ieee80211_rx_bss_free(struct cfg80211_bss *cbss)
33 {
34         struct ieee80211_bss *bss = (void *)cbss->priv;
35
36         kfree(bss_mesh_id(bss));
37         kfree(bss_mesh_cfg(bss));
38 }
39
40 void ieee80211_rx_bss_put(struct ieee80211_local *local,
41                           struct ieee80211_bss *bss)
42 {
43         if (!bss)
44                 return;
45         cfg80211_put_bss(container_of((void *)bss, struct cfg80211_bss, priv));
46 }
47
48 static bool is_uapsd_supported(struct ieee802_11_elems *elems)
49 {
50         u8 qos_info;
51
52         if (elems->wmm_info && elems->wmm_info_len == 7
53             && elems->wmm_info[5] == 1)
54                 qos_info = elems->wmm_info[6];
55         else if (elems->wmm_param && elems->wmm_param_len == 24
56                  && elems->wmm_param[5] == 1)
57                 qos_info = elems->wmm_param[6];
58         else
59                 /* no valid wmm information or parameter element found */
60                 return false;
61
62         return qos_info & IEEE80211_WMM_IE_AP_QOSINFO_UAPSD;
63 }
64
65 struct ieee80211_bss *
66 ieee80211_bss_info_update(struct ieee80211_local *local,
67                           struct ieee80211_rx_status *rx_status,
68                           struct ieee80211_mgmt *mgmt,
69                           size_t len,
70                           struct ieee802_11_elems *elems,
71                           struct ieee80211_channel *channel,
72                           bool beacon)
73 {
74         struct cfg80211_bss *cbss;
75         struct ieee80211_bss *bss;
76         int clen, srlen;
77         s32 signal = 0;
78
79         if (local->hw.flags & IEEE80211_HW_SIGNAL_DBM)
80                 signal = rx_status->signal * 100;
81         else if (local->hw.flags & IEEE80211_HW_SIGNAL_UNSPEC)
82                 signal = (rx_status->signal * 100) / local->hw.max_signal;
83
84         cbss = cfg80211_inform_bss_frame(local->hw.wiphy, channel,
85                                          mgmt, len, signal, GFP_ATOMIC);
86         if (!cbss)
87                 return NULL;
88
89         cbss->free_priv = ieee80211_rx_bss_free;
90         bss = (void *)cbss->priv;
91
92         bss->device_ts = rx_status->device_timestamp;
93
94         if (elems->parse_error) {
95                 if (beacon)
96                         bss->corrupt_data |= IEEE80211_BSS_CORRUPT_BEACON;
97                 else
98                         bss->corrupt_data |= IEEE80211_BSS_CORRUPT_PROBE_RESP;
99         } else {
100                 if (beacon)
101                         bss->corrupt_data &= ~IEEE80211_BSS_CORRUPT_BEACON;
102                 else
103                         bss->corrupt_data &= ~IEEE80211_BSS_CORRUPT_PROBE_RESP;
104         }
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                         (!elems->parse_error ||
109                          !(bss->valid_data & IEEE80211_BSS_VALID_ERP))) {
110                 bss->erp_value = elems->erp_info[0];
111                 bss->has_erp_value = true;
112                 if (!elems->parse_error)
113                         bss->valid_data |= IEEE80211_BSS_VALID_ERP;
114         }
115
116         if (elems->tim && (!elems->parse_error ||
117                            !(bss->valid_data & IEEE80211_BSS_VALID_DTIM))) {
118                 struct ieee80211_tim_ie *tim_ie = elems->tim;
119                 bss->dtim_period = tim_ie->dtim_period;
120                 if (!elems->parse_error)
121                                 bss->valid_data |= IEEE80211_BSS_VALID_DTIM;
122         }
123
124         /* If the beacon had no TIM IE, or it was invalid, use 1 */
125         if (beacon && !bss->dtim_period)
126                 bss->dtim_period = 1;
127
128         /* replace old supported rates if we get new values */
129         if (!elems->parse_error ||
130             !(bss->valid_data & IEEE80211_BSS_VALID_RATES)) {
131                 srlen = 0;
132                 if (elems->supp_rates) {
133                         clen = IEEE80211_MAX_SUPP_RATES;
134                         if (clen > elems->supp_rates_len)
135                                 clen = elems->supp_rates_len;
136                         memcpy(bss->supp_rates, elems->supp_rates, clen);
137                         srlen += clen;
138                 }
139                 if (elems->ext_supp_rates) {
140                         clen = IEEE80211_MAX_SUPP_RATES - srlen;
141                         if (clen > elems->ext_supp_rates_len)
142                                 clen = elems->ext_supp_rates_len;
143                         memcpy(bss->supp_rates + srlen, elems->ext_supp_rates,
144                                clen);
145                         srlen += clen;
146                 }
147                 if (srlen) {
148                         bss->supp_rates_len = srlen;
149                         if (!elems->parse_error)
150                                 bss->valid_data |= IEEE80211_BSS_VALID_RATES;
151                 }
152         }
153
154         if (!elems->parse_error ||
155             !(bss->valid_data & IEEE80211_BSS_VALID_WMM)) {
156                 bss->wmm_used = elems->wmm_param || elems->wmm_info;
157                 bss->uapsd_supported = is_uapsd_supported(elems);
158                 if (!elems->parse_error)
159                         bss->valid_data |= IEEE80211_BSS_VALID_WMM;
160         }
161
162         if (!beacon)
163                 bss->last_probe_resp = jiffies;
164
165         return bss;
166 }
167
168 void ieee80211_scan_rx(struct ieee80211_local *local, struct sk_buff *skb)
169 {
170         struct ieee80211_rx_status *rx_status = IEEE80211_SKB_RXCB(skb);
171         struct ieee80211_sub_if_data *sdata1, *sdata2;
172         struct ieee80211_mgmt *mgmt = (void *)skb->data;
173         struct ieee80211_bss *bss;
174         u8 *elements;
175         struct ieee80211_channel *channel;
176         size_t baselen;
177         int freq;
178         bool beacon;
179         struct ieee802_11_elems elems;
180
181         if (skb->len < 24 ||
182             (!ieee80211_is_probe_resp(mgmt->frame_control) &&
183              !ieee80211_is_beacon(mgmt->frame_control)))
184                 return;
185
186         sdata1 = rcu_dereference(local->scan_sdata);
187         sdata2 = rcu_dereference(local->sched_scan_sdata);
188
189         if (likely(!sdata1 && !sdata2))
190                 return;
191
192         if (ieee80211_is_probe_resp(mgmt->frame_control)) {
193                 /* ignore ProbeResp to foreign address */
194                 if ((!sdata1 || !ether_addr_equal(mgmt->da, sdata1->vif.addr)) &&
195                     (!sdata2 || !ether_addr_equal(mgmt->da, sdata2->vif.addr)))
196                         return;
197
198                 elements = mgmt->u.probe_resp.variable;
199                 baselen = offsetof(struct ieee80211_mgmt, u.probe_resp.variable);
200                 beacon = false;
201         } else {
202                 baselen = offsetof(struct ieee80211_mgmt, u.beacon.variable);
203                 elements = mgmt->u.beacon.variable;
204                 beacon = true;
205         }
206
207         if (baselen > skb->len)
208                 return;
209
210         ieee802_11_parse_elems(elements, skb->len - baselen, &elems);
211
212         if (elems.ds_params && elems.ds_params_len == 1)
213                 freq = ieee80211_channel_to_frequency(elems.ds_params[0],
214                                                       rx_status->band);
215         else
216                 freq = rx_status->freq;
217
218         channel = ieee80211_get_channel(local->hw.wiphy, freq);
219
220         if (!channel || channel->flags & IEEE80211_CHAN_DISABLED)
221                 return;
222
223         bss = ieee80211_bss_info_update(local, rx_status,
224                                         mgmt, skb->len, &elems,
225                                         channel, beacon);
226         if (bss)
227                 ieee80211_rx_bss_put(local, bss);
228 }
229
230 /* return false if no more work */
231 static bool ieee80211_prep_hw_scan(struct ieee80211_local *local)
232 {
233         struct cfg80211_scan_request *req = local->scan_req;
234         enum ieee80211_band band;
235         int i, ielen, n_chans;
236
237         do {
238                 if (local->hw_scan_band == IEEE80211_NUM_BANDS)
239                         return false;
240
241                 band = local->hw_scan_band;
242                 n_chans = 0;
243                 for (i = 0; i < req->n_channels; i++) {
244                         if (req->channels[i]->band == band) {
245                                 local->hw_scan_req->channels[n_chans] =
246                                                         req->channels[i];
247                                 n_chans++;
248                         }
249                 }
250
251                 local->hw_scan_band++;
252         } while (!n_chans);
253
254         local->hw_scan_req->n_channels = n_chans;
255
256         ielen = ieee80211_build_preq_ies(local, (u8 *)local->hw_scan_req->ie,
257                                          req->ie, req->ie_len, band,
258                                          req->rates[band], 0);
259         local->hw_scan_req->ie_len = ielen;
260         local->hw_scan_req->no_cck = req->no_cck;
261
262         return true;
263 }
264
265 static void __ieee80211_scan_completed(struct ieee80211_hw *hw, bool aborted,
266                                        bool was_hw_scan)
267 {
268         struct ieee80211_local *local = hw_to_local(hw);
269
270         lockdep_assert_held(&local->mtx);
271
272         /*
273          * It's ok to abort a not-yet-running scan (that
274          * we have one at all will be verified by checking
275          * local->scan_req next), but not to complete it
276          * successfully.
277          */
278         if (WARN_ON(!local->scanning && !aborted))
279                 aborted = true;
280
281         if (WARN_ON(!local->scan_req))
282                 return;
283
284         if (was_hw_scan && !aborted && ieee80211_prep_hw_scan(local)) {
285                 int rc;
286
287                 rc = drv_hw_scan(local,
288                         rcu_dereference_protected(local->scan_sdata,
289                                                   lockdep_is_held(&local->mtx)),
290                         local->hw_scan_req);
291
292                 if (rc == 0)
293                         return;
294         }
295
296         kfree(local->hw_scan_req);
297         local->hw_scan_req = NULL;
298
299         if (local->scan_req != local->int_scan_req)
300                 cfg80211_scan_done(local->scan_req, aborted);
301         local->scan_req = NULL;
302         local->scan_sdata = NULL;
303
304         local->scanning = 0;
305         local->scan_channel = NULL;
306
307         /* Set power back to normal operating levels. */
308         ieee80211_hw_config(local, 0);
309
310         if (!was_hw_scan) {
311                 ieee80211_configure_filter(local);
312                 drv_sw_scan_complete(local);
313                 ieee80211_offchannel_return(local, true);
314         }
315
316         ieee80211_recalc_idle(local);
317
318         ieee80211_mlme_notify_scan_completed(local);
319         ieee80211_ibss_notify_scan_completed(local);
320         ieee80211_mesh_notify_scan_completed(local);
321         ieee80211_start_next_roc(local);
322 }
323
324 void ieee80211_scan_completed(struct ieee80211_hw *hw, bool aborted)
325 {
326         struct ieee80211_local *local = hw_to_local(hw);
327
328         trace_api_scan_completed(local, aborted);
329
330         set_bit(SCAN_COMPLETED, &local->scanning);
331         if (aborted)
332                 set_bit(SCAN_ABORTED, &local->scanning);
333         ieee80211_queue_delayed_work(&local->hw, &local->scan_work, 0);
334 }
335 EXPORT_SYMBOL(ieee80211_scan_completed);
336
337 static int ieee80211_start_sw_scan(struct ieee80211_local *local)
338 {
339         /*
340          * Hardware/driver doesn't support hw_scan, so use software
341          * scanning instead. First send a nullfunc frame with power save
342          * bit on so that AP will buffer the frames for us while we are not
343          * listening, then send probe requests to each channel and wait for
344          * the responses. After all channels are scanned, tune back to the
345          * original channel and send a nullfunc frame with power save bit
346          * off to trigger the AP to send us all the buffered frames.
347          *
348          * Note that while local->sw_scanning is true everything else but
349          * nullfunc frames and probe requests will be dropped in
350          * ieee80211_tx_h_check_assoc().
351          */
352         drv_sw_scan_start(local);
353
354         local->leave_oper_channel_time = jiffies;
355         local->next_scan_state = SCAN_DECISION;
356         local->scan_channel_idx = 0;
357
358         ieee80211_offchannel_stop_vifs(local, true);
359
360         ieee80211_configure_filter(local);
361
362         /* We need to set power level at maximum rate for scanning. */
363         ieee80211_hw_config(local, 0);
364
365         ieee80211_queue_delayed_work(&local->hw,
366                                      &local->scan_work, 0);
367
368         return 0;
369 }
370
371 static bool ieee80211_can_scan(struct ieee80211_local *local,
372                                struct ieee80211_sub_if_data *sdata)
373 {
374         if (!list_empty(&local->roc_list))
375                 return false;
376
377         if (sdata->vif.type == NL80211_IFTYPE_STATION &&
378             sdata->u.mgd.flags & (IEEE80211_STA_BEACON_POLL |
379                                   IEEE80211_STA_CONNECTION_POLL))
380                 return false;
381
382         return true;
383 }
384
385 void ieee80211_run_deferred_scan(struct ieee80211_local *local)
386 {
387         lockdep_assert_held(&local->mtx);
388
389         if (!local->scan_req || local->scanning)
390                 return;
391
392         if (!ieee80211_can_scan(local,
393                                 rcu_dereference_protected(
394                                         local->scan_sdata,
395                                         lockdep_is_held(&local->mtx))))
396                 return;
397
398         ieee80211_queue_delayed_work(&local->hw, &local->scan_work,
399                                      round_jiffies_relative(0));
400 }
401
402 static void ieee80211_scan_state_send_probe(struct ieee80211_local *local,
403                                             unsigned long *next_delay)
404 {
405         int i;
406         struct ieee80211_sub_if_data *sdata;
407         enum ieee80211_band band = local->hw.conf.channel->band;
408
409         sdata = rcu_dereference_protected(local->scan_sdata,
410                                           lockdep_is_held(&local->mtx));;
411
412         for (i = 0; i < local->scan_req->n_ssids; i++)
413                 ieee80211_send_probe_req(
414                         sdata, NULL,
415                         local->scan_req->ssids[i].ssid,
416                         local->scan_req->ssids[i].ssid_len,
417                         local->scan_req->ie, local->scan_req->ie_len,
418                         local->scan_req->rates[band], false,
419                         local->scan_req->no_cck);
420
421         /*
422          * After sending probe requests, wait for probe responses
423          * on the channel.
424          */
425         *next_delay = IEEE80211_CHANNEL_TIME;
426         local->next_scan_state = SCAN_DECISION;
427 }
428
429 static int __ieee80211_start_scan(struct ieee80211_sub_if_data *sdata,
430                                   struct cfg80211_scan_request *req)
431 {
432         struct ieee80211_local *local = sdata->local;
433         int rc;
434
435         lockdep_assert_held(&local->mtx);
436
437         if (local->scan_req)
438                 return -EBUSY;
439
440         if (!ieee80211_can_scan(local, sdata)) {
441                 /* wait for the work to finish/time out */
442                 local->scan_req = req;
443                 rcu_assign_pointer(local->scan_sdata, sdata);
444                 return 0;
445         }
446
447         if (local->ops->hw_scan) {
448                 u8 *ies;
449
450                 local->hw_scan_req = kmalloc(
451                                 sizeof(*local->hw_scan_req) +
452                                 req->n_channels * sizeof(req->channels[0]) +
453                                 2 + IEEE80211_MAX_SSID_LEN + local->scan_ies_len +
454                                 req->ie_len, GFP_KERNEL);
455                 if (!local->hw_scan_req)
456                         return -ENOMEM;
457
458                 local->hw_scan_req->ssids = req->ssids;
459                 local->hw_scan_req->n_ssids = req->n_ssids;
460                 ies = (u8 *)local->hw_scan_req +
461                         sizeof(*local->hw_scan_req) +
462                         req->n_channels * sizeof(req->channels[0]);
463                 local->hw_scan_req->ie = ies;
464
465                 local->hw_scan_band = 0;
466
467                 /*
468                  * After allocating local->hw_scan_req, we must
469                  * go through until ieee80211_prep_hw_scan(), so
470                  * anything that might be changed here and leave
471                  * this function early must not go after this
472                  * allocation.
473                  */
474         }
475
476         local->scan_req = req;
477         rcu_assign_pointer(local->scan_sdata, sdata);
478
479         if (local->ops->hw_scan) {
480                 __set_bit(SCAN_HW_SCANNING, &local->scanning);
481         } else if ((req->n_channels == 1) &&
482                    (req->channels[0]->center_freq ==
483                     local->hw.conf.channel->center_freq)) {
484
485                 /* If we are scanning only on the current channel, then
486                  * we do not need to stop normal activities
487                  */
488                 unsigned long next_delay;
489
490                 __set_bit(SCAN_ONCHANNEL_SCANNING, &local->scanning);
491
492                 ieee80211_recalc_idle(local);
493
494                 /* Notify driver scan is starting, keep order of operations
495                  * same as normal software scan, in case that matters. */
496                 drv_sw_scan_start(local);
497
498                 ieee80211_configure_filter(local); /* accept probe-responses */
499
500                 /* We need to ensure power level is at max for scanning. */
501                 ieee80211_hw_config(local, 0);
502
503                 if ((req->channels[0]->flags &
504                      IEEE80211_CHAN_PASSIVE_SCAN) ||
505                     !local->scan_req->n_ssids) {
506                         next_delay = IEEE80211_PASSIVE_CHANNEL_TIME;
507                 } else {
508                         ieee80211_scan_state_send_probe(local, &next_delay);
509                         next_delay = IEEE80211_CHANNEL_TIME;
510                 }
511
512                 /* Now, just wait a bit and we are all done! */
513                 ieee80211_queue_delayed_work(&local->hw, &local->scan_work,
514                                              next_delay);
515                 return 0;
516         } else {
517                 /* Do normal software scan */
518                 __set_bit(SCAN_SW_SCANNING, &local->scanning);
519         }
520
521         ieee80211_recalc_idle(local);
522
523         if (local->ops->hw_scan) {
524                 WARN_ON(!ieee80211_prep_hw_scan(local));
525                 rc = drv_hw_scan(local, sdata, local->hw_scan_req);
526         } else
527                 rc = ieee80211_start_sw_scan(local);
528
529         if (rc) {
530                 kfree(local->hw_scan_req);
531                 local->hw_scan_req = NULL;
532                 local->scanning = 0;
533
534                 ieee80211_recalc_idle(local);
535
536                 local->scan_req = NULL;
537                 rcu_assign_pointer(local->scan_sdata, NULL);
538         }
539
540         return rc;
541 }
542
543 static unsigned long
544 ieee80211_scan_get_channel_time(struct ieee80211_channel *chan)
545 {
546         /*
547          * TODO: channel switching also consumes quite some time,
548          * add that delay as well to get a better estimation
549          */
550         if (chan->flags & IEEE80211_CHAN_PASSIVE_SCAN)
551                 return IEEE80211_PASSIVE_CHANNEL_TIME;
552         return IEEE80211_PROBE_DELAY + IEEE80211_CHANNEL_TIME;
553 }
554
555 static void ieee80211_scan_state_decision(struct ieee80211_local *local,
556                                           unsigned long *next_delay)
557 {
558         bool associated = false;
559         bool tx_empty = true;
560         bool bad_latency;
561         bool listen_int_exceeded;
562         unsigned long min_beacon_int = 0;
563         struct ieee80211_sub_if_data *sdata;
564         struct ieee80211_channel *next_chan;
565
566         /*
567          * check if at least one STA interface is associated,
568          * check if at least one STA interface has pending tx frames
569          * and grab the lowest used beacon interval
570          */
571         mutex_lock(&local->iflist_mtx);
572         list_for_each_entry(sdata, &local->interfaces, list) {
573                 if (!ieee80211_sdata_running(sdata))
574                         continue;
575
576                 if (sdata->vif.type == NL80211_IFTYPE_STATION) {
577                         if (sdata->u.mgd.associated) {
578                                 associated = true;
579
580                                 if (sdata->vif.bss_conf.beacon_int <
581                                     min_beacon_int || min_beacon_int == 0)
582                                         min_beacon_int =
583                                                 sdata->vif.bss_conf.beacon_int;
584
585                                 if (!qdisc_all_tx_empty(sdata->dev)) {
586                                         tx_empty = false;
587                                         break;
588                                 }
589                         }
590                 }
591         }
592         mutex_unlock(&local->iflist_mtx);
593
594         next_chan = local->scan_req->channels[local->scan_channel_idx];
595
596         /*
597          * we're currently scanning a different channel, let's
598          * see if we can scan another channel without interfering
599          * with the current traffic situation.
600          *
601          * Since we don't know if the AP has pending frames for us
602          * we can only check for our tx queues and use the current
603          * pm_qos requirements for rx. Hence, if no tx traffic occurs
604          * at all we will scan as many channels in a row as the pm_qos
605          * latency allows us to. Additionally we also check for the
606          * currently negotiated listen interval to prevent losing
607          * frames unnecessarily.
608          *
609          * Otherwise switch back to the operating channel.
610          */
611
612         bad_latency = time_after(jiffies +
613                         ieee80211_scan_get_channel_time(next_chan),
614                         local->leave_oper_channel_time +
615                         usecs_to_jiffies(pm_qos_request(PM_QOS_NETWORK_LATENCY)));
616
617         listen_int_exceeded = time_after(jiffies +
618                         ieee80211_scan_get_channel_time(next_chan),
619                         local->leave_oper_channel_time +
620                         usecs_to_jiffies(min_beacon_int * 1024) *
621                         local->hw.conf.listen_interval);
622
623         if (associated && (!tx_empty || bad_latency || listen_int_exceeded))
624                 local->next_scan_state = SCAN_SUSPEND;
625         else
626                 local->next_scan_state = SCAN_SET_CHANNEL;
627
628         *next_delay = 0;
629 }
630
631 static void ieee80211_scan_state_set_channel(struct ieee80211_local *local,
632                                              unsigned long *next_delay)
633 {
634         int skip;
635         struct ieee80211_channel *chan;
636
637         skip = 0;
638         chan = local->scan_req->channels[local->scan_channel_idx];
639
640         local->scan_channel = chan;
641
642         if (ieee80211_hw_config(local, IEEE80211_CONF_CHANGE_CHANNEL))
643                 skip = 1;
644
645         /* advance state machine to next channel/band */
646         local->scan_channel_idx++;
647
648         if (skip) {
649                 /* if we skip this channel return to the decision state */
650                 local->next_scan_state = SCAN_DECISION;
651                 return;
652         }
653
654         /*
655          * Probe delay is used to update the NAV, cf. 11.1.3.2.2
656          * (which unfortunately doesn't say _why_ step a) is done,
657          * but it waits for the probe delay or until a frame is
658          * received - and the received frame would update the NAV).
659          * For now, we do not support waiting until a frame is
660          * received.
661          *
662          * In any case, it is not necessary for a passive scan.
663          */
664         if (chan->flags & IEEE80211_CHAN_PASSIVE_SCAN ||
665             !local->scan_req->n_ssids) {
666                 *next_delay = IEEE80211_PASSIVE_CHANNEL_TIME;
667                 local->next_scan_state = SCAN_DECISION;
668                 return;
669         }
670
671         /* active scan, send probes */
672         *next_delay = IEEE80211_PROBE_DELAY;
673         local->next_scan_state = SCAN_SEND_PROBE;
674 }
675
676 static void ieee80211_scan_state_suspend(struct ieee80211_local *local,
677                                          unsigned long *next_delay)
678 {
679         /* switch back to the operating channel */
680         local->scan_channel = NULL;
681         ieee80211_hw_config(local, IEEE80211_CONF_CHANGE_CHANNEL);
682
683         /*
684          * Re-enable vifs and beaconing.  Leave PS
685          * in off-channel state..will put that back
686          * on-channel at the end of scanning.
687          */
688         ieee80211_offchannel_return(local, false);
689
690         *next_delay = HZ / 5;
691         /* afterwards, resume scan & go to next channel */
692         local->next_scan_state = SCAN_RESUME;
693 }
694
695 static void ieee80211_scan_state_resume(struct ieee80211_local *local,
696                                         unsigned long *next_delay)
697 {
698         /* PS already is in off-channel mode */
699         ieee80211_offchannel_stop_vifs(local, false);
700
701         if (local->ops->flush) {
702                 drv_flush(local, false);
703                 *next_delay = 0;
704         } else
705                 *next_delay = HZ / 10;
706
707         /* remember when we left the operating channel */
708         local->leave_oper_channel_time = jiffies;
709
710         /* advance to the next channel to be scanned */
711         local->next_scan_state = SCAN_SET_CHANNEL;
712 }
713
714 void ieee80211_scan_work(struct work_struct *work)
715 {
716         struct ieee80211_local *local =
717                 container_of(work, struct ieee80211_local, scan_work.work);
718         struct ieee80211_sub_if_data *sdata;
719         unsigned long next_delay = 0;
720         bool aborted, hw_scan;
721
722         mutex_lock(&local->mtx);
723
724         sdata = rcu_dereference_protected(local->scan_sdata,
725                                           lockdep_is_held(&local->mtx));
726
727         /* When scanning on-channel, the first-callback means completed. */
728         if (test_bit(SCAN_ONCHANNEL_SCANNING, &local->scanning)) {
729                 aborted = test_and_clear_bit(SCAN_ABORTED, &local->scanning);
730                 goto out_complete;
731         }
732
733         if (test_and_clear_bit(SCAN_COMPLETED, &local->scanning)) {
734                 aborted = test_and_clear_bit(SCAN_ABORTED, &local->scanning);
735                 goto out_complete;
736         }
737
738         if (!sdata || !local->scan_req)
739                 goto out;
740
741         if (local->scan_req && !local->scanning) {
742                 struct cfg80211_scan_request *req = local->scan_req;
743                 int rc;
744
745                 local->scan_req = NULL;
746                 rcu_assign_pointer(local->scan_sdata, NULL);
747
748                 rc = __ieee80211_start_scan(sdata, req);
749                 if (rc) {
750                         /* need to complete scan in cfg80211 */
751                         local->scan_req = req;
752                         aborted = true;
753                         goto out_complete;
754                 } else
755                         goto out;
756         }
757
758         /*
759          * Avoid re-scheduling when the sdata is going away.
760          */
761         if (!ieee80211_sdata_running(sdata)) {
762                 aborted = true;
763                 goto out_complete;
764         }
765
766         /*
767          * as long as no delay is required advance immediately
768          * without scheduling a new work
769          */
770         do {
771                 if (!ieee80211_sdata_running(sdata)) {
772                         aborted = true;
773                         goto out_complete;
774                 }
775
776                 switch (local->next_scan_state) {
777                 case SCAN_DECISION:
778                         /* if no more bands/channels left, complete scan */
779                         if (local->scan_channel_idx >= local->scan_req->n_channels) {
780                                 aborted = false;
781                                 goto out_complete;
782                         }
783                         ieee80211_scan_state_decision(local, &next_delay);
784                         break;
785                 case SCAN_SET_CHANNEL:
786                         ieee80211_scan_state_set_channel(local, &next_delay);
787                         break;
788                 case SCAN_SEND_PROBE:
789                         ieee80211_scan_state_send_probe(local, &next_delay);
790                         break;
791                 case SCAN_SUSPEND:
792                         ieee80211_scan_state_suspend(local, &next_delay);
793                         break;
794                 case SCAN_RESUME:
795                         ieee80211_scan_state_resume(local, &next_delay);
796                         break;
797                 }
798         } while (next_delay == 0);
799
800         ieee80211_queue_delayed_work(&local->hw, &local->scan_work, next_delay);
801         goto out;
802
803 out_complete:
804         hw_scan = test_bit(SCAN_HW_SCANNING, &local->scanning);
805         __ieee80211_scan_completed(&local->hw, aborted, hw_scan);
806 out:
807         mutex_unlock(&local->mtx);
808 }
809
810 int ieee80211_request_scan(struct ieee80211_sub_if_data *sdata,
811                            struct cfg80211_scan_request *req)
812 {
813         int res;
814
815         mutex_lock(&sdata->local->mtx);
816         res = __ieee80211_start_scan(sdata, req);
817         mutex_unlock(&sdata->local->mtx);
818
819         return res;
820 }
821
822 int ieee80211_request_internal_scan(struct ieee80211_sub_if_data *sdata,
823                                     const u8 *ssid, u8 ssid_len,
824                                     struct ieee80211_channel *chan)
825 {
826         struct ieee80211_local *local = sdata->local;
827         int ret = -EBUSY;
828         enum ieee80211_band band;
829
830         mutex_lock(&local->mtx);
831
832         /* busy scanning */
833         if (local->scan_req)
834                 goto unlock;
835
836         /* fill internal scan request */
837         if (!chan) {
838                 int i, nchan = 0;
839
840                 for (band = 0; band < IEEE80211_NUM_BANDS; band++) {
841                         if (!local->hw.wiphy->bands[band])
842                                 continue;
843                         for (i = 0;
844                              i < local->hw.wiphy->bands[band]->n_channels;
845                              i++) {
846                                 local->int_scan_req->channels[nchan] =
847                                     &local->hw.wiphy->bands[band]->channels[i];
848                                 nchan++;
849                         }
850                 }
851
852                 local->int_scan_req->n_channels = nchan;
853         } else {
854                 local->int_scan_req->channels[0] = chan;
855                 local->int_scan_req->n_channels = 1;
856         }
857
858         local->int_scan_req->ssids = &local->scan_ssid;
859         local->int_scan_req->n_ssids = 1;
860         memcpy(local->int_scan_req->ssids[0].ssid, ssid, IEEE80211_MAX_SSID_LEN);
861         local->int_scan_req->ssids[0].ssid_len = ssid_len;
862
863         ret = __ieee80211_start_scan(sdata, sdata->local->int_scan_req);
864  unlock:
865         mutex_unlock(&local->mtx);
866         return ret;
867 }
868
869 /*
870  * Only call this function when a scan can't be queued -- under RTNL.
871  */
872 void ieee80211_scan_cancel(struct ieee80211_local *local)
873 {
874         /*
875          * We are canceling software scan, or deferred scan that was not
876          * yet really started (see __ieee80211_start_scan ).
877          *
878          * Regarding hardware scan:
879          * - we can not call  __ieee80211_scan_completed() as when
880          *   SCAN_HW_SCANNING bit is set this function change
881          *   local->hw_scan_req to operate on 5G band, what race with
882          *   driver which can use local->hw_scan_req
883          *
884          * - we can not cancel scan_work since driver can schedule it
885          *   by ieee80211_scan_completed(..., true) to finish scan
886          *
887          * Hence we only call the cancel_hw_scan() callback, but the low-level
888          * driver is still responsible for calling ieee80211_scan_completed()
889          * after the scan was completed/aborted.
890          */
891
892         mutex_lock(&local->mtx);
893         if (!local->scan_req)
894                 goto out;
895
896         if (test_bit(SCAN_HW_SCANNING, &local->scanning)) {
897                 if (local->ops->cancel_hw_scan)
898                         drv_cancel_hw_scan(local,
899                                 rcu_dereference_protected(local->scan_sdata,
900                                                 lockdep_is_held(&local->mtx)));
901                 goto out;
902         }
903
904         /*
905          * If the work is currently running, it must be blocked on
906          * the mutex, but we'll set scan_sdata = NULL and it'll
907          * simply exit once it acquires the mutex.
908          */
909         cancel_delayed_work(&local->scan_work);
910         /* and clean up */
911         __ieee80211_scan_completed(&local->hw, true, false);
912 out:
913         mutex_unlock(&local->mtx);
914 }
915
916 int ieee80211_request_sched_scan_start(struct ieee80211_sub_if_data *sdata,
917                                        struct cfg80211_sched_scan_request *req)
918 {
919         struct ieee80211_local *local = sdata->local;
920         int ret, i;
921
922         mutex_lock(&local->mtx);
923
924         if (rcu_access_pointer(local->sched_scan_sdata)) {
925                 ret = -EBUSY;
926                 goto out;
927         }
928
929         if (!local->ops->sched_scan_start) {
930                 ret = -ENOTSUPP;
931                 goto out;
932         }
933
934         for (i = 0; i < IEEE80211_NUM_BANDS; i++) {
935                 if (!local->hw.wiphy->bands[i])
936                         continue;
937
938                 local->sched_scan_ies.ie[i] = kzalloc(2 +
939                                                       IEEE80211_MAX_SSID_LEN +
940                                                       local->scan_ies_len +
941                                                       req->ie_len,
942                                                       GFP_KERNEL);
943                 if (!local->sched_scan_ies.ie[i]) {
944                         ret = -ENOMEM;
945                         goto out_free;
946                 }
947
948                 local->sched_scan_ies.len[i] =
949                         ieee80211_build_preq_ies(local,
950                                                  local->sched_scan_ies.ie[i],
951                                                  req->ie, req->ie_len, i,
952                                                  (u32) -1, 0);
953         }
954
955         ret = drv_sched_scan_start(local, sdata, req,
956                                    &local->sched_scan_ies);
957         if (ret == 0) {
958                 rcu_assign_pointer(local->sched_scan_sdata, sdata);
959                 goto out;
960         }
961
962 out_free:
963         while (i > 0)
964                 kfree(local->sched_scan_ies.ie[--i]);
965 out:
966         mutex_unlock(&local->mtx);
967         return ret;
968 }
969
970 int ieee80211_request_sched_scan_stop(struct ieee80211_sub_if_data *sdata)
971 {
972         struct ieee80211_local *local = sdata->local;
973         int ret = 0, i;
974
975         mutex_lock(&local->mtx);
976
977         if (!local->ops->sched_scan_stop) {
978                 ret = -ENOTSUPP;
979                 goto out;
980         }
981
982         if (rcu_access_pointer(local->sched_scan_sdata)) {
983                 for (i = 0; i < IEEE80211_NUM_BANDS; i++)
984                         kfree(local->sched_scan_ies.ie[i]);
985
986                 drv_sched_scan_stop(local, sdata);
987                 rcu_assign_pointer(local->sched_scan_sdata, NULL);
988         }
989 out:
990         mutex_unlock(&local->mtx);
991
992         return ret;
993 }
994
995 void ieee80211_sched_scan_results(struct ieee80211_hw *hw)
996 {
997         struct ieee80211_local *local = hw_to_local(hw);
998
999         trace_api_sched_scan_results(local);
1000
1001         cfg80211_sched_scan_results(hw->wiphy);
1002 }
1003 EXPORT_SYMBOL(ieee80211_sched_scan_results);
1004
1005 void ieee80211_sched_scan_stopped_work(struct work_struct *work)
1006 {
1007         struct ieee80211_local *local =
1008                 container_of(work, struct ieee80211_local,
1009                              sched_scan_stopped_work);
1010         int i;
1011
1012         mutex_lock(&local->mtx);
1013
1014         if (!rcu_access_pointer(local->sched_scan_sdata)) {
1015                 mutex_unlock(&local->mtx);
1016                 return;
1017         }
1018
1019         for (i = 0; i < IEEE80211_NUM_BANDS; i++)
1020                 kfree(local->sched_scan_ies.ie[i]);
1021
1022         rcu_assign_pointer(local->sched_scan_sdata, NULL);
1023
1024         mutex_unlock(&local->mtx);
1025
1026         cfg80211_sched_scan_stopped(local->hw.wiphy);
1027 }
1028
1029 void ieee80211_sched_scan_stopped(struct ieee80211_hw *hw)
1030 {
1031         struct ieee80211_local *local = hw_to_local(hw);
1032
1033         trace_api_sched_scan_stopped(local);
1034
1035         ieee80211_queue_work(&local->hw, &local->sched_scan_stopped_work);
1036 }
1037 EXPORT_SYMBOL(ieee80211_sched_scan_stopped);