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mac80211: fix ibss scanning
[~shefty/rdma-dev.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         bool beacon;
178         struct ieee802_11_elems elems;
179
180         if (skb->len < 24 ||
181             (!ieee80211_is_probe_resp(mgmt->frame_control) &&
182              !ieee80211_is_beacon(mgmt->frame_control)))
183                 return;
184
185         sdata1 = rcu_dereference(local->scan_sdata);
186         sdata2 = rcu_dereference(local->sched_scan_sdata);
187
188         if (likely(!sdata1 && !sdata2))
189                 return;
190
191         if (ieee80211_is_probe_resp(mgmt->frame_control)) {
192                 /* ignore ProbeResp to foreign address */
193                 if ((!sdata1 || !ether_addr_equal(mgmt->da, sdata1->vif.addr)) &&
194                     (!sdata2 || !ether_addr_equal(mgmt->da, sdata2->vif.addr)))
195                         return;
196
197                 elements = mgmt->u.probe_resp.variable;
198                 baselen = offsetof(struct ieee80211_mgmt, u.probe_resp.variable);
199                 beacon = false;
200         } else {
201                 baselen = offsetof(struct ieee80211_mgmt, u.beacon.variable);
202                 elements = mgmt->u.beacon.variable;
203                 beacon = true;
204         }
205
206         if (baselen > skb->len)
207                 return;
208
209         ieee802_11_parse_elems(elements, skb->len - baselen, &elems);
210
211         channel = ieee80211_get_channel(local->hw.wiphy, rx_status->freq);
212
213         if (!channel || channel->flags & IEEE80211_CHAN_DISABLED)
214                 return;
215
216         bss = ieee80211_bss_info_update(local, rx_status,
217                                         mgmt, skb->len, &elems,
218                                         channel, beacon);
219         if (bss)
220                 ieee80211_rx_bss_put(local, bss);
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                                          local->hw_scan_ies_bufsize,
251                                          req->ie, req->ie_len, band,
252                                          req->rates[band], 0);
253         local->hw_scan_req->ie_len = ielen;
254         local->hw_scan_req->no_cck = req->no_cck;
255
256         return true;
257 }
258
259 static void __ieee80211_scan_completed(struct ieee80211_hw *hw, bool aborted,
260                                        bool was_hw_scan)
261 {
262         struct ieee80211_local *local = hw_to_local(hw);
263
264         lockdep_assert_held(&local->mtx);
265
266         /*
267          * It's ok to abort a not-yet-running scan (that
268          * we have one at all will be verified by checking
269          * local->scan_req next), but not to complete it
270          * successfully.
271          */
272         if (WARN_ON(!local->scanning && !aborted))
273                 aborted = true;
274
275         if (WARN_ON(!local->scan_req))
276                 return;
277
278         if (was_hw_scan && !aborted && ieee80211_prep_hw_scan(local)) {
279                 int rc;
280
281                 rc = drv_hw_scan(local,
282                         rcu_dereference_protected(local->scan_sdata,
283                                                   lockdep_is_held(&local->mtx)),
284                         local->hw_scan_req);
285
286                 if (rc == 0)
287                         return;
288         }
289
290         kfree(local->hw_scan_req);
291         local->hw_scan_req = NULL;
292
293         if (local->scan_req != local->int_scan_req)
294                 cfg80211_scan_done(local->scan_req, aborted);
295         local->scan_req = NULL;
296         rcu_assign_pointer(local->scan_sdata, NULL);
297
298         local->scanning = 0;
299         local->scan_channel = NULL;
300
301         /* Set power back to normal operating levels. */
302         ieee80211_hw_config(local, 0);
303
304         if (!was_hw_scan) {
305                 ieee80211_configure_filter(local);
306                 drv_sw_scan_complete(local);
307                 ieee80211_offchannel_return(local, true);
308         }
309
310         ieee80211_recalc_idle(local);
311
312         ieee80211_mlme_notify_scan_completed(local);
313         ieee80211_ibss_notify_scan_completed(local);
314         ieee80211_mesh_notify_scan_completed(local);
315         ieee80211_start_next_roc(local);
316 }
317
318 void ieee80211_scan_completed(struct ieee80211_hw *hw, bool aborted)
319 {
320         struct ieee80211_local *local = hw_to_local(hw);
321
322         trace_api_scan_completed(local, aborted);
323
324         set_bit(SCAN_COMPLETED, &local->scanning);
325         if (aborted)
326                 set_bit(SCAN_ABORTED, &local->scanning);
327         ieee80211_queue_delayed_work(&local->hw, &local->scan_work, 0);
328 }
329 EXPORT_SYMBOL(ieee80211_scan_completed);
330
331 static int ieee80211_start_sw_scan(struct ieee80211_local *local)
332 {
333         /* Software scan is not supported in multi-channel cases */
334         if (local->use_chanctx)
335                 return -EOPNOTSUPP;
336
337         /*
338          * Hardware/driver doesn't support hw_scan, so use software
339          * scanning instead. First send a nullfunc frame with power save
340          * bit on so that AP will buffer the frames for us while we are not
341          * listening, then send probe requests to each channel and wait for
342          * the responses. After all channels are scanned, tune back to the
343          * original channel and send a nullfunc frame with power save bit
344          * off to trigger the AP to send us all the buffered frames.
345          *
346          * Note that while local->sw_scanning is true everything else but
347          * nullfunc frames and probe requests will be dropped in
348          * ieee80211_tx_h_check_assoc().
349          */
350         drv_sw_scan_start(local);
351
352         local->leave_oper_channel_time = jiffies;
353         local->next_scan_state = SCAN_DECISION;
354         local->scan_channel_idx = 0;
355
356         ieee80211_offchannel_stop_vifs(local, true);
357
358         ieee80211_configure_filter(local);
359
360         /* We need to set power level at maximum rate for scanning. */
361         ieee80211_hw_config(local, 0);
362
363         ieee80211_queue_delayed_work(&local->hw,
364                                      &local->scan_work, 0);
365
366         return 0;
367 }
368
369 static bool ieee80211_can_scan(struct ieee80211_local *local,
370                                struct ieee80211_sub_if_data *sdata)
371 {
372         if (!list_empty(&local->roc_list))
373                 return false;
374
375         if (sdata->vif.type == NL80211_IFTYPE_STATION &&
376             sdata->u.mgd.flags & (IEEE80211_STA_BEACON_POLL |
377                                   IEEE80211_STA_CONNECTION_POLL))
378                 return false;
379
380         return true;
381 }
382
383 void ieee80211_run_deferred_scan(struct ieee80211_local *local)
384 {
385         lockdep_assert_held(&local->mtx);
386
387         if (!local->scan_req || local->scanning)
388                 return;
389
390         if (!ieee80211_can_scan(local,
391                                 rcu_dereference_protected(
392                                         local->scan_sdata,
393                                         lockdep_is_held(&local->mtx))))
394                 return;
395
396         ieee80211_queue_delayed_work(&local->hw, &local->scan_work,
397                                      round_jiffies_relative(0));
398 }
399
400 static void ieee80211_scan_state_send_probe(struct ieee80211_local *local,
401                                             unsigned long *next_delay)
402 {
403         int i;
404         struct ieee80211_sub_if_data *sdata;
405         enum ieee80211_band band = local->hw.conf.channel->band;
406
407         sdata = rcu_dereference_protected(local->scan_sdata,
408                                           lockdep_is_held(&local->mtx));
409
410         for (i = 0; i < local->scan_req->n_ssids; i++)
411                 ieee80211_send_probe_req(
412                         sdata, NULL,
413                         local->scan_req->ssids[i].ssid,
414                         local->scan_req->ssids[i].ssid_len,
415                         local->scan_req->ie, local->scan_req->ie_len,
416                         local->scan_req->rates[band], false,
417                         local->scan_req->no_cck,
418                         local->hw.conf.channel, true);
419
420         /*
421          * After sending probe requests, wait for probe responses
422          * on the channel.
423          */
424         *next_delay = IEEE80211_CHANNEL_TIME;
425         local->next_scan_state = SCAN_DECISION;
426 }
427
428 static int __ieee80211_start_scan(struct ieee80211_sub_if_data *sdata,
429                                   struct cfg80211_scan_request *req)
430 {
431         struct ieee80211_local *local = sdata->local;
432         int rc;
433
434         lockdep_assert_held(&local->mtx);
435
436         if (local->scan_req)
437                 return -EBUSY;
438
439         if (!ieee80211_can_scan(local, sdata)) {
440                 /* wait for the work to finish/time out */
441                 local->scan_req = req;
442                 rcu_assign_pointer(local->scan_sdata, sdata);
443                 return 0;
444         }
445
446         if (local->ops->hw_scan) {
447                 u8 *ies;
448
449                 local->hw_scan_ies_bufsize = 2 + IEEE80211_MAX_SSID_LEN +
450                                              local->scan_ies_len +
451                                              req->ie_len;
452                 local->hw_scan_req = kmalloc(
453                                 sizeof(*local->hw_scan_req) +
454                                 req->n_channels * sizeof(req->channels[0]) +
455                                 local->hw_scan_ies_bufsize, GFP_KERNEL);
456                 if (!local->hw_scan_req)
457                         return -ENOMEM;
458
459                 local->hw_scan_req->ssids = req->ssids;
460                 local->hw_scan_req->n_ssids = req->n_ssids;
461                 ies = (u8 *)local->hw_scan_req +
462                         sizeof(*local->hw_scan_req) +
463                         req->n_channels * sizeof(req->channels[0]);
464                 local->hw_scan_req->ie = ies;
465                 local->hw_scan_req->flags = req->flags;
466
467                 local->hw_scan_band = 0;
468
469                 /*
470                  * After allocating local->hw_scan_req, we must
471                  * go through until ieee80211_prep_hw_scan(), so
472                  * anything that might be changed here and leave
473                  * this function early must not go after this
474                  * allocation.
475                  */
476         }
477
478         local->scan_req = req;
479         rcu_assign_pointer(local->scan_sdata, sdata);
480
481         if (local->ops->hw_scan) {
482                 __set_bit(SCAN_HW_SCANNING, &local->scanning);
483         } else if ((req->n_channels == 1) &&
484                    (req->channels[0] == local->_oper_channel)) {
485                 /*
486                  * If we are scanning only on the operating channel
487                  * then we do not need to stop normal activities
488                  */
489                 unsigned long next_delay;
490
491                 __set_bit(SCAN_ONCHANNEL_SCANNING, &local->scanning);
492
493                 ieee80211_recalc_idle(local);
494
495                 /* Notify driver scan is starting, keep order of operations
496                  * same as normal software scan, in case that matters. */
497                 drv_sw_scan_start(local);
498
499                 ieee80211_configure_filter(local); /* accept probe-responses */
500
501                 /* We need to ensure power level is at max for scanning. */
502                 ieee80211_hw_config(local, 0);
503
504                 if ((req->channels[0]->flags &
505                      IEEE80211_CHAN_PASSIVE_SCAN) ||
506                     !local->scan_req->n_ssids) {
507                         next_delay = IEEE80211_PASSIVE_CHANNEL_TIME;
508                 } else {
509                         ieee80211_scan_state_send_probe(local, &next_delay);
510                         next_delay = IEEE80211_CHANNEL_TIME;
511                 }
512
513                 /* Now, just wait a bit and we are all done! */
514                 ieee80211_queue_delayed_work(&local->hw, &local->scan_work,
515                                              next_delay);
516                 return 0;
517         } else {
518                 /* Do normal software scan */
519                 __set_bit(SCAN_SW_SCANNING, &local->scanning);
520         }
521
522         ieee80211_recalc_idle(local);
523
524         if (local->ops->hw_scan) {
525                 WARN_ON(!ieee80211_prep_hw_scan(local));
526                 rc = drv_hw_scan(local, sdata, local->hw_scan_req);
527         } else
528                 rc = ieee80211_start_sw_scan(local);
529
530         if (rc) {
531                 kfree(local->hw_scan_req);
532                 local->hw_scan_req = NULL;
533                 local->scanning = 0;
534
535                 ieee80211_recalc_idle(local);
536
537                 local->scan_req = NULL;
538                 rcu_assign_pointer(local->scan_sdata, NULL);
539         }
540
541         return rc;
542 }
543
544 static unsigned long
545 ieee80211_scan_get_channel_time(struct ieee80211_channel *chan)
546 {
547         /*
548          * TODO: channel switching also consumes quite some time,
549          * add that delay as well to get a better estimation
550          */
551         if (chan->flags & IEEE80211_CHAN_PASSIVE_SCAN)
552                 return IEEE80211_PASSIVE_CHANNEL_TIME;
553         return IEEE80211_PROBE_DELAY + IEEE80211_CHANNEL_TIME;
554 }
555
556 static void ieee80211_scan_state_decision(struct ieee80211_local *local,
557                                           unsigned long *next_delay)
558 {
559         bool associated = false;
560         bool tx_empty = true;
561         bool bad_latency;
562         bool listen_int_exceeded;
563         unsigned long min_beacon_int = 0;
564         struct ieee80211_sub_if_data *sdata;
565         struct ieee80211_channel *next_chan;
566         enum mac80211_scan_state next_scan_state;
567
568         /*
569          * check if at least one STA interface is associated,
570          * check if at least one STA interface has pending tx frames
571          * and grab the lowest used beacon interval
572          */
573         mutex_lock(&local->iflist_mtx);
574         list_for_each_entry(sdata, &local->interfaces, list) {
575                 if (!ieee80211_sdata_running(sdata))
576                         continue;
577
578                 if (sdata->vif.type == NL80211_IFTYPE_STATION) {
579                         if (sdata->u.mgd.associated) {
580                                 associated = true;
581
582                                 if (sdata->vif.bss_conf.beacon_int <
583                                     min_beacon_int || min_beacon_int == 0)
584                                         min_beacon_int =
585                                                 sdata->vif.bss_conf.beacon_int;
586
587                                 if (!qdisc_all_tx_empty(sdata->dev)) {
588                                         tx_empty = false;
589                                         break;
590                                 }
591                         }
592                 }
593         }
594         mutex_unlock(&local->iflist_mtx);
595
596         next_chan = local->scan_req->channels[local->scan_channel_idx];
597
598         /*
599          * we're currently scanning a different channel, let's
600          * see if we can scan another channel without interfering
601          * with the current traffic situation.
602          *
603          * Since we don't know if the AP has pending frames for us
604          * we can only check for our tx queues and use the current
605          * pm_qos requirements for rx. Hence, if no tx traffic occurs
606          * at all we will scan as many channels in a row as the pm_qos
607          * latency allows us to. Additionally we also check for the
608          * currently negotiated listen interval to prevent losing
609          * frames unnecessarily.
610          *
611          * Otherwise switch back to the operating channel.
612          */
613
614         bad_latency = time_after(jiffies +
615                         ieee80211_scan_get_channel_time(next_chan),
616                         local->leave_oper_channel_time +
617                         usecs_to_jiffies(pm_qos_request(PM_QOS_NETWORK_LATENCY)));
618
619         listen_int_exceeded = time_after(jiffies +
620                         ieee80211_scan_get_channel_time(next_chan),
621                         local->leave_oper_channel_time +
622                         usecs_to_jiffies(min_beacon_int * 1024) *
623                         local->hw.conf.listen_interval);
624
625         if (associated && !tx_empty) {
626                 if (local->scan_req->flags & NL80211_SCAN_FLAG_LOW_PRIORITY)
627                         next_scan_state = SCAN_ABORT;
628                 else
629                         next_scan_state = SCAN_SUSPEND;
630         } else if (associated && (bad_latency || listen_int_exceeded)) {
631                 next_scan_state = SCAN_SUSPEND;
632         } else {
633                 next_scan_state = SCAN_SET_CHANNEL;
634         }
635
636         local->next_scan_state = next_scan_state;
637
638         *next_delay = 0;
639 }
640
641 static void ieee80211_scan_state_set_channel(struct ieee80211_local *local,
642                                              unsigned long *next_delay)
643 {
644         int skip;
645         struct ieee80211_channel *chan;
646
647         skip = 0;
648         chan = local->scan_req->channels[local->scan_channel_idx];
649
650         local->scan_channel = chan;
651
652         if (ieee80211_hw_config(local, IEEE80211_CONF_CHANGE_CHANNEL))
653                 skip = 1;
654
655         /* advance state machine to next channel/band */
656         local->scan_channel_idx++;
657
658         if (skip) {
659                 /* if we skip this channel return to the decision state */
660                 local->next_scan_state = SCAN_DECISION;
661                 return;
662         }
663
664         /*
665          * Probe delay is used to update the NAV, cf. 11.1.3.2.2
666          * (which unfortunately doesn't say _why_ step a) is done,
667          * but it waits for the probe delay or until a frame is
668          * received - and the received frame would update the NAV).
669          * For now, we do not support waiting until a frame is
670          * received.
671          *
672          * In any case, it is not necessary for a passive scan.
673          */
674         if (chan->flags & IEEE80211_CHAN_PASSIVE_SCAN ||
675             !local->scan_req->n_ssids) {
676                 *next_delay = IEEE80211_PASSIVE_CHANNEL_TIME;
677                 local->next_scan_state = SCAN_DECISION;
678                 return;
679         }
680
681         /* active scan, send probes */
682         *next_delay = IEEE80211_PROBE_DELAY;
683         local->next_scan_state = SCAN_SEND_PROBE;
684 }
685
686 static void ieee80211_scan_state_suspend(struct ieee80211_local *local,
687                                          unsigned long *next_delay)
688 {
689         /* switch back to the operating channel */
690         local->scan_channel = NULL;
691         ieee80211_hw_config(local, IEEE80211_CONF_CHANGE_CHANNEL);
692
693         /*
694          * Re-enable vifs and beaconing.  Leave PS
695          * in off-channel state..will put that back
696          * on-channel at the end of scanning.
697          */
698         ieee80211_offchannel_return(local, false);
699
700         *next_delay = HZ / 5;
701         /* afterwards, resume scan & go to next channel */
702         local->next_scan_state = SCAN_RESUME;
703 }
704
705 static void ieee80211_scan_state_resume(struct ieee80211_local *local,
706                                         unsigned long *next_delay)
707 {
708         /* PS already is in off-channel mode */
709         ieee80211_offchannel_stop_vifs(local, false);
710
711         if (local->ops->flush) {
712                 drv_flush(local, false);
713                 *next_delay = 0;
714         } else
715                 *next_delay = HZ / 10;
716
717         /* remember when we left the operating channel */
718         local->leave_oper_channel_time = jiffies;
719
720         /* advance to the next channel to be scanned */
721         local->next_scan_state = SCAN_SET_CHANNEL;
722 }
723
724 void ieee80211_scan_work(struct work_struct *work)
725 {
726         struct ieee80211_local *local =
727                 container_of(work, struct ieee80211_local, scan_work.work);
728         struct ieee80211_sub_if_data *sdata;
729         unsigned long next_delay = 0;
730         bool aborted, hw_scan;
731
732         mutex_lock(&local->mtx);
733
734         sdata = rcu_dereference_protected(local->scan_sdata,
735                                           lockdep_is_held(&local->mtx));
736
737         /* When scanning on-channel, the first-callback means completed. */
738         if (test_bit(SCAN_ONCHANNEL_SCANNING, &local->scanning)) {
739                 aborted = test_and_clear_bit(SCAN_ABORTED, &local->scanning);
740                 goto out_complete;
741         }
742
743         if (test_and_clear_bit(SCAN_COMPLETED, &local->scanning)) {
744                 aborted = test_and_clear_bit(SCAN_ABORTED, &local->scanning);
745                 goto out_complete;
746         }
747
748         if (!sdata || !local->scan_req)
749                 goto out;
750
751         if (local->scan_req && !local->scanning) {
752                 struct cfg80211_scan_request *req = local->scan_req;
753                 int rc;
754
755                 local->scan_req = NULL;
756                 rcu_assign_pointer(local->scan_sdata, NULL);
757
758                 rc = __ieee80211_start_scan(sdata, req);
759                 if (rc) {
760                         /* need to complete scan in cfg80211 */
761                         local->scan_req = req;
762                         aborted = true;
763                         goto out_complete;
764                 } else
765                         goto out;
766         }
767
768         /*
769          * Avoid re-scheduling when the sdata is going away.
770          */
771         if (!ieee80211_sdata_running(sdata)) {
772                 aborted = true;
773                 goto out_complete;
774         }
775
776         /*
777          * as long as no delay is required advance immediately
778          * without scheduling a new work
779          */
780         do {
781                 if (!ieee80211_sdata_running(sdata)) {
782                         aborted = true;
783                         goto out_complete;
784                 }
785
786                 switch (local->next_scan_state) {
787                 case SCAN_DECISION:
788                         /* if no more bands/channels left, complete scan */
789                         if (local->scan_channel_idx >= local->scan_req->n_channels) {
790                                 aborted = false;
791                                 goto out_complete;
792                         }
793                         ieee80211_scan_state_decision(local, &next_delay);
794                         break;
795                 case SCAN_SET_CHANNEL:
796                         ieee80211_scan_state_set_channel(local, &next_delay);
797                         break;
798                 case SCAN_SEND_PROBE:
799                         ieee80211_scan_state_send_probe(local, &next_delay);
800                         break;
801                 case SCAN_SUSPEND:
802                         ieee80211_scan_state_suspend(local, &next_delay);
803                         break;
804                 case SCAN_RESUME:
805                         ieee80211_scan_state_resume(local, &next_delay);
806                         break;
807                 case SCAN_ABORT:
808                         aborted = true;
809                         goto out_complete;
810                 }
811         } while (next_delay == 0);
812
813         ieee80211_queue_delayed_work(&local->hw, &local->scan_work, next_delay);
814         goto out;
815
816 out_complete:
817         hw_scan = test_bit(SCAN_HW_SCANNING, &local->scanning);
818         __ieee80211_scan_completed(&local->hw, aborted, hw_scan);
819 out:
820         mutex_unlock(&local->mtx);
821 }
822
823 int ieee80211_request_scan(struct ieee80211_sub_if_data *sdata,
824                            struct cfg80211_scan_request *req)
825 {
826         int res;
827
828         mutex_lock(&sdata->local->mtx);
829         res = __ieee80211_start_scan(sdata, req);
830         mutex_unlock(&sdata->local->mtx);
831
832         return res;
833 }
834
835 int ieee80211_request_ibss_scan(struct ieee80211_sub_if_data *sdata,
836                                 const u8 *ssid, u8 ssid_len,
837                                 struct ieee80211_channel *chan)
838 {
839         struct ieee80211_local *local = sdata->local;
840         int ret = -EBUSY;
841         enum ieee80211_band band;
842
843         mutex_lock(&local->mtx);
844
845         /* busy scanning */
846         if (local->scan_req)
847                 goto unlock;
848
849         /* fill internal scan request */
850         if (!chan) {
851                 int i, max_n;
852                 int n_ch = 0;
853
854                 for (band = 0; band < IEEE80211_NUM_BANDS; band++) {
855                         if (!local->hw.wiphy->bands[band])
856                                 continue;
857
858                         max_n = local->hw.wiphy->bands[band]->n_channels;
859                         for (i = 0; i < max_n; i++) {
860                                 struct ieee80211_channel *tmp_ch =
861                                     &local->hw.wiphy->bands[band]->channels[i];
862
863                                 if (tmp_ch->flags & (IEEE80211_CHAN_NO_IBSS |
864                                                      IEEE80211_CHAN_DISABLED))
865                                         continue;
866
867                                 local->int_scan_req->channels[n_ch] = tmp_ch;
868                                 n_ch++;
869                         }
870                 }
871
872                 if (WARN_ON_ONCE(n_ch == 0))
873                         goto unlock;
874
875                 local->int_scan_req->n_channels = n_ch;
876         } else {
877                 if (WARN_ON_ONCE(chan->flags & (IEEE80211_CHAN_NO_IBSS |
878                                                 IEEE80211_CHAN_DISABLED)))
879                         goto unlock;
880
881                 local->int_scan_req->channels[0] = chan;
882                 local->int_scan_req->n_channels = 1;
883         }
884
885         local->int_scan_req->ssids = &local->scan_ssid;
886         local->int_scan_req->n_ssids = 1;
887         memcpy(local->int_scan_req->ssids[0].ssid, ssid, IEEE80211_MAX_SSID_LEN);
888         local->int_scan_req->ssids[0].ssid_len = ssid_len;
889
890         ret = __ieee80211_start_scan(sdata, sdata->local->int_scan_req);
891  unlock:
892         mutex_unlock(&local->mtx);
893         return ret;
894 }
895
896 /*
897  * Only call this function when a scan can't be queued -- under RTNL.
898  */
899 void ieee80211_scan_cancel(struct ieee80211_local *local)
900 {
901         /*
902          * We are canceling software scan, or deferred scan that was not
903          * yet really started (see __ieee80211_start_scan ).
904          *
905          * Regarding hardware scan:
906          * - we can not call  __ieee80211_scan_completed() as when
907          *   SCAN_HW_SCANNING bit is set this function change
908          *   local->hw_scan_req to operate on 5G band, what race with
909          *   driver which can use local->hw_scan_req
910          *
911          * - we can not cancel scan_work since driver can schedule it
912          *   by ieee80211_scan_completed(..., true) to finish scan
913          *
914          * Hence we only call the cancel_hw_scan() callback, but the low-level
915          * driver is still responsible for calling ieee80211_scan_completed()
916          * after the scan was completed/aborted.
917          */
918
919         mutex_lock(&local->mtx);
920         if (!local->scan_req)
921                 goto out;
922
923         if (test_bit(SCAN_HW_SCANNING, &local->scanning)) {
924                 if (local->ops->cancel_hw_scan)
925                         drv_cancel_hw_scan(local,
926                                 rcu_dereference_protected(local->scan_sdata,
927                                                 lockdep_is_held(&local->mtx)));
928                 goto out;
929         }
930
931         /*
932          * If the work is currently running, it must be blocked on
933          * the mutex, but we'll set scan_sdata = NULL and it'll
934          * simply exit once it acquires the mutex.
935          */
936         cancel_delayed_work(&local->scan_work);
937         /* and clean up */
938         __ieee80211_scan_completed(&local->hw, true, false);
939 out:
940         mutex_unlock(&local->mtx);
941 }
942
943 int ieee80211_request_sched_scan_start(struct ieee80211_sub_if_data *sdata,
944                                        struct cfg80211_sched_scan_request *req)
945 {
946         struct ieee80211_local *local = sdata->local;
947         struct ieee80211_sched_scan_ies sched_scan_ies = {};
948         int ret, i, iebufsz;
949
950         iebufsz = 2 + IEEE80211_MAX_SSID_LEN +
951                   local->scan_ies_len + req->ie_len;
952
953         mutex_lock(&local->mtx);
954
955         if (rcu_access_pointer(local->sched_scan_sdata)) {
956                 ret = -EBUSY;
957                 goto out;
958         }
959
960         if (!local->ops->sched_scan_start) {
961                 ret = -ENOTSUPP;
962                 goto out;
963         }
964
965         for (i = 0; i < IEEE80211_NUM_BANDS; i++) {
966                 if (!local->hw.wiphy->bands[i])
967                         continue;
968
969                 sched_scan_ies.ie[i] = kzalloc(iebufsz, GFP_KERNEL);
970                 if (!sched_scan_ies.ie[i]) {
971                         ret = -ENOMEM;
972                         goto out_free;
973                 }
974
975                 sched_scan_ies.len[i] =
976                         ieee80211_build_preq_ies(local, sched_scan_ies.ie[i],
977                                                  iebufsz, req->ie, req->ie_len,
978                                                  i, (u32) -1, 0);
979         }
980
981         ret = drv_sched_scan_start(local, sdata, req, &sched_scan_ies);
982         if (ret == 0)
983                 rcu_assign_pointer(local->sched_scan_sdata, sdata);
984
985 out_free:
986         while (i > 0)
987                 kfree(sched_scan_ies.ie[--i]);
988 out:
989         mutex_unlock(&local->mtx);
990         return ret;
991 }
992
993 int ieee80211_request_sched_scan_stop(struct ieee80211_sub_if_data *sdata)
994 {
995         struct ieee80211_local *local = sdata->local;
996         int ret = 0;
997
998         mutex_lock(&local->mtx);
999
1000         if (!local->ops->sched_scan_stop) {
1001                 ret = -ENOTSUPP;
1002                 goto out;
1003         }
1004
1005         if (rcu_access_pointer(local->sched_scan_sdata))
1006                 drv_sched_scan_stop(local, sdata);
1007
1008 out:
1009         mutex_unlock(&local->mtx);
1010
1011         return ret;
1012 }
1013
1014 void ieee80211_sched_scan_results(struct ieee80211_hw *hw)
1015 {
1016         struct ieee80211_local *local = hw_to_local(hw);
1017
1018         trace_api_sched_scan_results(local);
1019
1020         cfg80211_sched_scan_results(hw->wiphy);
1021 }
1022 EXPORT_SYMBOL(ieee80211_sched_scan_results);
1023
1024 void ieee80211_sched_scan_stopped_work(struct work_struct *work)
1025 {
1026         struct ieee80211_local *local =
1027                 container_of(work, struct ieee80211_local,
1028                              sched_scan_stopped_work);
1029
1030         mutex_lock(&local->mtx);
1031
1032         if (!rcu_access_pointer(local->sched_scan_sdata)) {
1033                 mutex_unlock(&local->mtx);
1034                 return;
1035         }
1036
1037         rcu_assign_pointer(local->sched_scan_sdata, NULL);
1038
1039         mutex_unlock(&local->mtx);
1040
1041         cfg80211_sched_scan_stopped(local->hw.wiphy);
1042 }
1043
1044 void ieee80211_sched_scan_stopped(struct ieee80211_hw *hw)
1045 {
1046         struct ieee80211_local *local = hw_to_local(hw);
1047
1048         trace_api_sched_scan_stopped(local);
1049
1050         ieee80211_queue_work(&local->hw, &local->sched_scan_stopped_work);
1051 }
1052 EXPORT_SYMBOL(ieee80211_sched_scan_stopped);