GNU Linux-libre 4.14.290-gnu1
[releases.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  * Copyright 2013-2015  Intel Mobile Communications GmbH
10  * Copyright 2016  Intel Deutschland GmbH
11  *
12  * This program is free software; you can redistribute it and/or modify
13  * it under the terms of the GNU General Public License version 2 as
14  * published by the Free Software Foundation.
15  */
16
17 #include <linux/if_arp.h>
18 #include <linux/etherdevice.h>
19 #include <linux/rtnetlink.h>
20 #include <net/sch_generic.h>
21 #include <linux/slab.h>
22 #include <linux/export.h>
23 #include <net/mac80211.h>
24
25 #include "ieee80211_i.h"
26 #include "driver-ops.h"
27 #include "mesh.h"
28
29 #define IEEE80211_PROBE_DELAY (HZ / 33)
30 #define IEEE80211_CHANNEL_TIME (HZ / 33)
31 #define IEEE80211_PASSIVE_CHANNEL_TIME (HZ / 9)
32
33 void ieee80211_rx_bss_put(struct ieee80211_local *local,
34                           struct ieee80211_bss *bss)
35 {
36         if (!bss)
37                 return;
38         cfg80211_put_bss(local->hw.wiphy,
39                          container_of((void *)bss, struct cfg80211_bss, priv));
40 }
41
42 static bool is_uapsd_supported(struct ieee802_11_elems *elems)
43 {
44         u8 qos_info;
45
46         if (elems->wmm_info && elems->wmm_info_len == 7
47             && elems->wmm_info[5] == 1)
48                 qos_info = elems->wmm_info[6];
49         else if (elems->wmm_param && elems->wmm_param_len == 24
50                  && elems->wmm_param[5] == 1)
51                 qos_info = elems->wmm_param[6];
52         else
53                 /* no valid wmm information or parameter element found */
54                 return false;
55
56         return qos_info & IEEE80211_WMM_IE_AP_QOSINFO_UAPSD;
57 }
58
59 struct ieee80211_bss *
60 ieee80211_bss_info_update(struct ieee80211_local *local,
61                           struct ieee80211_rx_status *rx_status,
62                           struct ieee80211_mgmt *mgmt, size_t len,
63                           struct ieee802_11_elems *elems,
64                           struct ieee80211_channel *channel)
65 {
66         bool beacon = ieee80211_is_beacon(mgmt->frame_control);
67         struct cfg80211_bss *cbss;
68         struct ieee80211_bss *bss;
69         int clen, srlen;
70         struct cfg80211_inform_bss bss_meta = {
71                 .boottime_ns = rx_status->boottime_ns,
72         };
73         bool signal_valid;
74         struct ieee80211_sub_if_data *scan_sdata;
75
76         if (ieee80211_hw_check(&local->hw, SIGNAL_DBM))
77                 bss_meta.signal = rx_status->signal * 100;
78         else if (ieee80211_hw_check(&local->hw, SIGNAL_UNSPEC))
79                 bss_meta.signal = (rx_status->signal * 100) / local->hw.max_signal;
80
81         bss_meta.scan_width = NL80211_BSS_CHAN_WIDTH_20;
82         if (rx_status->bw == RATE_INFO_BW_5)
83                 bss_meta.scan_width = NL80211_BSS_CHAN_WIDTH_5;
84         else if (rx_status->bw == RATE_INFO_BW_10)
85                 bss_meta.scan_width = NL80211_BSS_CHAN_WIDTH_10;
86
87         bss_meta.chan = channel;
88
89         rcu_read_lock();
90         scan_sdata = rcu_dereference(local->scan_sdata);
91         if (scan_sdata && scan_sdata->vif.type == NL80211_IFTYPE_STATION &&
92             scan_sdata->vif.bss_conf.assoc &&
93             ieee80211_have_rx_timestamp(rx_status)) {
94                 bss_meta.parent_tsf =
95                         ieee80211_calculate_rx_timestamp(local, rx_status,
96                                                          len + FCS_LEN, 24);
97                 ether_addr_copy(bss_meta.parent_bssid,
98                                 scan_sdata->vif.bss_conf.bssid);
99         }
100         rcu_read_unlock();
101
102         cbss = cfg80211_inform_bss_frame_data(local->hw.wiphy, &bss_meta,
103                                               mgmt, len, GFP_ATOMIC);
104         if (!cbss)
105                 return NULL;
106         /* In case the signal is invalid update the status */
107         signal_valid = abs(channel->center_freq - cbss->channel->center_freq)
108                 <= local->hw.wiphy->max_adj_channel_rssi_comp;
109         if (!signal_valid)
110                 rx_status->flag |= RX_FLAG_NO_SIGNAL_VAL;
111
112         bss = (void *)cbss->priv;
113
114         if (beacon)
115                 bss->device_ts_beacon = rx_status->device_timestamp;
116         else
117                 bss->device_ts_presp = rx_status->device_timestamp;
118
119         if (elems->parse_error) {
120                 if (beacon)
121                         bss->corrupt_data |= IEEE80211_BSS_CORRUPT_BEACON;
122                 else
123                         bss->corrupt_data |= IEEE80211_BSS_CORRUPT_PROBE_RESP;
124         } else {
125                 if (beacon)
126                         bss->corrupt_data &= ~IEEE80211_BSS_CORRUPT_BEACON;
127                 else
128                         bss->corrupt_data &= ~IEEE80211_BSS_CORRUPT_PROBE_RESP;
129         }
130
131         /* save the ERP value so that it is available at association time */
132         if (elems->erp_info && (!elems->parse_error ||
133                                 !(bss->valid_data & IEEE80211_BSS_VALID_ERP))) {
134                 bss->erp_value = elems->erp_info[0];
135                 bss->has_erp_value = true;
136                 if (!elems->parse_error)
137                         bss->valid_data |= IEEE80211_BSS_VALID_ERP;
138         }
139
140         /* replace old supported rates if we get new values */
141         if (!elems->parse_error ||
142             !(bss->valid_data & IEEE80211_BSS_VALID_RATES)) {
143                 srlen = 0;
144                 if (elems->supp_rates) {
145                         clen = IEEE80211_MAX_SUPP_RATES;
146                         if (clen > elems->supp_rates_len)
147                                 clen = elems->supp_rates_len;
148                         memcpy(bss->supp_rates, elems->supp_rates, clen);
149                         srlen += clen;
150                 }
151                 if (elems->ext_supp_rates) {
152                         clen = IEEE80211_MAX_SUPP_RATES - srlen;
153                         if (clen > elems->ext_supp_rates_len)
154                                 clen = elems->ext_supp_rates_len;
155                         memcpy(bss->supp_rates + srlen, elems->ext_supp_rates,
156                                clen);
157                         srlen += clen;
158                 }
159                 if (srlen) {
160                         bss->supp_rates_len = srlen;
161                         if (!elems->parse_error)
162                                 bss->valid_data |= IEEE80211_BSS_VALID_RATES;
163                 }
164         }
165
166         if (!elems->parse_error ||
167             !(bss->valid_data & IEEE80211_BSS_VALID_WMM)) {
168                 bss->wmm_used = elems->wmm_param || elems->wmm_info;
169                 bss->uapsd_supported = is_uapsd_supported(elems);
170                 if (!elems->parse_error)
171                         bss->valid_data |= IEEE80211_BSS_VALID_WMM;
172         }
173
174         if (beacon) {
175                 struct ieee80211_supported_band *sband =
176                         local->hw.wiphy->bands[rx_status->band];
177                 if (!(rx_status->encoding == RX_ENC_HT) &&
178                     !(rx_status->encoding == RX_ENC_VHT))
179                         bss->beacon_rate =
180                                 &sband->bitrates[rx_status->rate_idx];
181         }
182
183         return bss;
184 }
185
186 void ieee80211_scan_rx(struct ieee80211_local *local, struct sk_buff *skb)
187 {
188         struct ieee80211_rx_status *rx_status = IEEE80211_SKB_RXCB(skb);
189         struct ieee80211_sub_if_data *sdata1, *sdata2;
190         struct ieee80211_mgmt *mgmt = (void *)skb->data;
191         struct ieee80211_bss *bss;
192         u8 *elements;
193         struct ieee80211_channel *channel;
194         size_t baselen;
195         struct ieee802_11_elems elems;
196
197         if (skb->len < 24 ||
198             (!ieee80211_is_probe_resp(mgmt->frame_control) &&
199              !ieee80211_is_beacon(mgmt->frame_control)))
200                 return;
201
202         sdata1 = rcu_dereference(local->scan_sdata);
203         sdata2 = rcu_dereference(local->sched_scan_sdata);
204
205         if (likely(!sdata1 && !sdata2))
206                 return;
207
208         if (test_and_clear_bit(SCAN_BEACON_WAIT, &local->scanning)) {
209                 /*
210                  * we were passive scanning because of radar/no-IR, but
211                  * the beacon/proberesp rx gives us an opportunity to upgrade
212                  * to active scan
213                  */
214                  set_bit(SCAN_BEACON_DONE, &local->scanning);
215                  ieee80211_queue_delayed_work(&local->hw, &local->scan_work, 0);
216         }
217
218         if (ieee80211_is_probe_resp(mgmt->frame_control)) {
219                 struct cfg80211_scan_request *scan_req;
220                 struct cfg80211_sched_scan_request *sched_scan_req;
221
222                 scan_req = rcu_dereference(local->scan_req);
223                 sched_scan_req = rcu_dereference(local->sched_scan_req);
224
225                 /* ignore ProbeResp to foreign address unless scanning
226                  * with randomised address
227                  */
228                 if (!(sdata1 &&
229                       (ether_addr_equal(mgmt->da, sdata1->vif.addr) ||
230                        scan_req->flags & NL80211_SCAN_FLAG_RANDOM_ADDR)) &&
231                     !(sdata2 &&
232                       (ether_addr_equal(mgmt->da, sdata2->vif.addr) ||
233                        sched_scan_req->flags & NL80211_SCAN_FLAG_RANDOM_ADDR)))
234                         return;
235
236                 elements = mgmt->u.probe_resp.variable;
237                 baselen = offsetof(struct ieee80211_mgmt, u.probe_resp.variable);
238         } else {
239                 baselen = offsetof(struct ieee80211_mgmt, u.beacon.variable);
240                 elements = mgmt->u.beacon.variable;
241         }
242
243         if (baselen > skb->len)
244                 return;
245
246         ieee802_11_parse_elems(elements, skb->len - baselen, false, &elems);
247
248         channel = ieee80211_get_channel(local->hw.wiphy, rx_status->freq);
249
250         if (!channel || channel->flags & IEEE80211_CHAN_DISABLED)
251                 return;
252
253         bss = ieee80211_bss_info_update(local, rx_status,
254                                         mgmt, skb->len, &elems,
255                                         channel);
256         if (bss)
257                 ieee80211_rx_bss_put(local, bss);
258 }
259
260 static void
261 ieee80211_prepare_scan_chandef(struct cfg80211_chan_def *chandef,
262                                enum nl80211_bss_scan_width scan_width)
263 {
264         memset(chandef, 0, sizeof(*chandef));
265         switch (scan_width) {
266         case NL80211_BSS_CHAN_WIDTH_5:
267                 chandef->width = NL80211_CHAN_WIDTH_5;
268                 break;
269         case NL80211_BSS_CHAN_WIDTH_10:
270                 chandef->width = NL80211_CHAN_WIDTH_10;
271                 break;
272         default:
273                 chandef->width = NL80211_CHAN_WIDTH_20_NOHT;
274                 break;
275         }
276 }
277
278 /* return false if no more work */
279 static bool ieee80211_prep_hw_scan(struct ieee80211_local *local)
280 {
281         struct cfg80211_scan_request *req;
282         struct cfg80211_chan_def chandef;
283         u8 bands_used = 0;
284         int i, ielen, n_chans;
285
286         req = rcu_dereference_protected(local->scan_req,
287                                         lockdep_is_held(&local->mtx));
288
289         if (test_bit(SCAN_HW_CANCELLED, &local->scanning))
290                 return false;
291
292         if (ieee80211_hw_check(&local->hw, SINGLE_SCAN_ON_ALL_BANDS)) {
293                 for (i = 0; i < req->n_channels; i++) {
294                         local->hw_scan_req->req.channels[i] = req->channels[i];
295                         bands_used |= BIT(req->channels[i]->band);
296                 }
297
298                 n_chans = req->n_channels;
299         } else {
300                 do {
301                         if (local->hw_scan_band == NUM_NL80211_BANDS)
302                                 return false;
303
304                         n_chans = 0;
305
306                         for (i = 0; i < req->n_channels; i++) {
307                                 if (req->channels[i]->band !=
308                                     local->hw_scan_band)
309                                         continue;
310                                 local->hw_scan_req->req.channels[n_chans] =
311                                                         req->channels[i];
312                                 n_chans++;
313                                 bands_used |= BIT(req->channels[i]->band);
314                         }
315
316                         local->hw_scan_band++;
317                 } while (!n_chans);
318         }
319
320         local->hw_scan_req->req.n_channels = n_chans;
321         ieee80211_prepare_scan_chandef(&chandef, req->scan_width);
322
323         ielen = ieee80211_build_preq_ies(local,
324                                          (u8 *)local->hw_scan_req->req.ie,
325                                          local->hw_scan_ies_bufsize,
326                                          &local->hw_scan_req->ies,
327                                          req->ie, req->ie_len,
328                                          bands_used, req->rates, &chandef);
329         local->hw_scan_req->req.ie_len = ielen;
330         local->hw_scan_req->req.no_cck = req->no_cck;
331         ether_addr_copy(local->hw_scan_req->req.mac_addr, req->mac_addr);
332         ether_addr_copy(local->hw_scan_req->req.mac_addr_mask,
333                         req->mac_addr_mask);
334         ether_addr_copy(local->hw_scan_req->req.bssid, req->bssid);
335
336         return true;
337 }
338
339 static void __ieee80211_scan_completed(struct ieee80211_hw *hw, bool aborted)
340 {
341         struct ieee80211_local *local = hw_to_local(hw);
342         bool hw_scan = local->ops->hw_scan;
343         bool was_scanning = local->scanning;
344         struct cfg80211_scan_request *scan_req;
345         struct ieee80211_sub_if_data *scan_sdata;
346         struct ieee80211_sub_if_data *sdata;
347
348         lockdep_assert_held(&local->mtx);
349
350         /*
351          * It's ok to abort a not-yet-running scan (that
352          * we have one at all will be verified by checking
353          * local->scan_req next), but not to complete it
354          * successfully.
355          */
356         if (WARN_ON(!local->scanning && !aborted))
357                 aborted = true;
358
359         if (WARN_ON(!local->scan_req))
360                 return;
361
362         if (hw_scan && !aborted &&
363             !ieee80211_hw_check(&local->hw, SINGLE_SCAN_ON_ALL_BANDS) &&
364             ieee80211_prep_hw_scan(local)) {
365                 int rc;
366
367                 rc = drv_hw_scan(local,
368                         rcu_dereference_protected(local->scan_sdata,
369                                                   lockdep_is_held(&local->mtx)),
370                         local->hw_scan_req);
371
372                 if (rc == 0)
373                         return;
374
375                 /* HW scan failed and is going to be reported as aborted,
376                  * so clear old scan info.
377                  */
378                 memset(&local->scan_info, 0, sizeof(local->scan_info));
379                 aborted = true;
380         }
381
382         kfree(local->hw_scan_req);
383         local->hw_scan_req = NULL;
384
385         scan_req = rcu_dereference_protected(local->scan_req,
386                                              lockdep_is_held(&local->mtx));
387
388         if (scan_req != local->int_scan_req) {
389                 local->scan_info.aborted = aborted;
390                 cfg80211_scan_done(scan_req, &local->scan_info);
391         }
392         RCU_INIT_POINTER(local->scan_req, NULL);
393
394         scan_sdata = rcu_dereference_protected(local->scan_sdata,
395                                                lockdep_is_held(&local->mtx));
396         RCU_INIT_POINTER(local->scan_sdata, NULL);
397
398         local->scanning = 0;
399         local->scan_chandef.chan = NULL;
400
401         /* Set power back to normal operating levels. */
402         ieee80211_hw_config(local, 0);
403
404         if (!hw_scan) {
405                 ieee80211_configure_filter(local);
406                 drv_sw_scan_complete(local, scan_sdata);
407                 ieee80211_offchannel_return(local);
408         }
409
410         ieee80211_recalc_idle(local);
411
412         ieee80211_mlme_notify_scan_completed(local);
413         ieee80211_ibss_notify_scan_completed(local);
414
415         /* Requeue all the work that might have been ignored while
416          * the scan was in progress; if there was none this will
417          * just be a no-op for the particular interface.
418          */
419         list_for_each_entry_rcu(sdata, &local->interfaces, list) {
420                 if (ieee80211_sdata_running(sdata))
421                         ieee80211_queue_work(&sdata->local->hw, &sdata->work);
422         }
423
424         if (was_scanning)
425                 ieee80211_start_next_roc(local);
426 }
427
428 void ieee80211_scan_completed(struct ieee80211_hw *hw,
429                               struct cfg80211_scan_info *info)
430 {
431         struct ieee80211_local *local = hw_to_local(hw);
432
433         trace_api_scan_completed(local, info->aborted);
434
435         set_bit(SCAN_COMPLETED, &local->scanning);
436         if (info->aborted)
437                 set_bit(SCAN_ABORTED, &local->scanning);
438
439         memcpy(&local->scan_info, info, sizeof(*info));
440
441         ieee80211_queue_delayed_work(&local->hw, &local->scan_work, 0);
442 }
443 EXPORT_SYMBOL(ieee80211_scan_completed);
444
445 static int ieee80211_start_sw_scan(struct ieee80211_local *local,
446                                    struct ieee80211_sub_if_data *sdata)
447 {
448         /* Software scan is not supported in multi-channel cases */
449         if (local->use_chanctx)
450                 return -EOPNOTSUPP;
451
452         /*
453          * Hardware/driver doesn't support hw_scan, so use software
454          * scanning instead. First send a nullfunc frame with power save
455          * bit on so that AP will buffer the frames for us while we are not
456          * listening, then send probe requests to each channel and wait for
457          * the responses. After all channels are scanned, tune back to the
458          * original channel and send a nullfunc frame with power save bit
459          * off to trigger the AP to send us all the buffered frames.
460          *
461          * Note that while local->sw_scanning is true everything else but
462          * nullfunc frames and probe requests will be dropped in
463          * ieee80211_tx_h_check_assoc().
464          */
465         drv_sw_scan_start(local, sdata, local->scan_addr);
466
467         local->leave_oper_channel_time = jiffies;
468         local->next_scan_state = SCAN_DECISION;
469         local->scan_channel_idx = 0;
470
471         ieee80211_offchannel_stop_vifs(local);
472
473         /* ensure nullfunc is transmitted before leaving operating channel */
474         ieee80211_flush_queues(local, NULL, false);
475
476         ieee80211_configure_filter(local);
477
478         /* We need to set power level at maximum rate for scanning. */
479         ieee80211_hw_config(local, 0);
480
481         ieee80211_queue_delayed_work(&local->hw,
482                                      &local->scan_work, 0);
483
484         return 0;
485 }
486
487 static bool ieee80211_can_scan(struct ieee80211_local *local,
488                                struct ieee80211_sub_if_data *sdata)
489 {
490         if (ieee80211_is_radar_required(local))
491                 return false;
492
493         if (!list_empty(&local->roc_list))
494                 return false;
495
496         if (sdata->vif.type == NL80211_IFTYPE_STATION &&
497             sdata->u.mgd.flags & IEEE80211_STA_CONNECTION_POLL)
498                 return false;
499
500         return true;
501 }
502
503 void ieee80211_run_deferred_scan(struct ieee80211_local *local)
504 {
505         lockdep_assert_held(&local->mtx);
506
507         if (!local->scan_req || local->scanning)
508                 return;
509
510         if (!ieee80211_can_scan(local,
511                                 rcu_dereference_protected(
512                                         local->scan_sdata,
513                                         lockdep_is_held(&local->mtx))))
514                 return;
515
516         ieee80211_queue_delayed_work(&local->hw, &local->scan_work,
517                                      round_jiffies_relative(0));
518 }
519
520 static void ieee80211_scan_state_send_probe(struct ieee80211_local *local,
521                                             unsigned long *next_delay)
522 {
523         int i;
524         struct ieee80211_sub_if_data *sdata;
525         struct cfg80211_scan_request *scan_req;
526         enum nl80211_band band = local->hw.conf.chandef.chan->band;
527         u32 tx_flags;
528
529         scan_req = rcu_dereference_protected(local->scan_req,
530                                              lockdep_is_held(&local->mtx));
531
532         tx_flags = IEEE80211_TX_INTFL_OFFCHAN_TX_OK;
533         if (scan_req->no_cck)
534                 tx_flags |= IEEE80211_TX_CTL_NO_CCK_RATE;
535
536         sdata = rcu_dereference_protected(local->scan_sdata,
537                                           lockdep_is_held(&local->mtx));
538
539         for (i = 0; i < scan_req->n_ssids; i++)
540                 ieee80211_send_probe_req(
541                         sdata, local->scan_addr, scan_req->bssid,
542                         scan_req->ssids[i].ssid, scan_req->ssids[i].ssid_len,
543                         scan_req->ie, scan_req->ie_len,
544                         scan_req->rates[band], false,
545                         tx_flags, local->hw.conf.chandef.chan, true);
546
547         /*
548          * After sending probe requests, wait for probe responses
549          * on the channel.
550          */
551         *next_delay = IEEE80211_CHANNEL_TIME;
552         local->next_scan_state = SCAN_DECISION;
553 }
554
555 static int __ieee80211_start_scan(struct ieee80211_sub_if_data *sdata,
556                                   struct cfg80211_scan_request *req)
557 {
558         struct ieee80211_local *local = sdata->local;
559         int rc;
560
561         lockdep_assert_held(&local->mtx);
562
563         if (local->scan_req || ieee80211_is_radar_required(local))
564                 return -EBUSY;
565
566         if (!ieee80211_can_scan(local, sdata)) {
567                 /* wait for the work to finish/time out */
568                 rcu_assign_pointer(local->scan_req, req);
569                 rcu_assign_pointer(local->scan_sdata, sdata);
570                 return 0;
571         }
572
573         if (local->ops->hw_scan) {
574                 u8 *ies;
575
576                 local->hw_scan_ies_bufsize = local->scan_ies_len + req->ie_len;
577
578                 if (ieee80211_hw_check(&local->hw, SINGLE_SCAN_ON_ALL_BANDS)) {
579                         int i, n_bands = 0;
580                         u8 bands_counted = 0;
581
582                         for (i = 0; i < req->n_channels; i++) {
583                                 if (bands_counted & BIT(req->channels[i]->band))
584                                         continue;
585                                 bands_counted |= BIT(req->channels[i]->band);
586                                 n_bands++;
587                         }
588
589                         local->hw_scan_ies_bufsize *= n_bands;
590                 }
591
592                 local->hw_scan_req = kmalloc(
593                                 sizeof(*local->hw_scan_req) +
594                                 req->n_channels * sizeof(req->channels[0]) +
595                                 local->hw_scan_ies_bufsize, GFP_KERNEL);
596                 if (!local->hw_scan_req)
597                         return -ENOMEM;
598
599                 local->hw_scan_req->req.ssids = req->ssids;
600                 local->hw_scan_req->req.n_ssids = req->n_ssids;
601                 ies = (u8 *)local->hw_scan_req +
602                         sizeof(*local->hw_scan_req) +
603                         req->n_channels * sizeof(req->channels[0]);
604                 local->hw_scan_req->req.ie = ies;
605                 local->hw_scan_req->req.flags = req->flags;
606                 eth_broadcast_addr(local->hw_scan_req->req.bssid);
607                 local->hw_scan_req->req.duration = req->duration;
608                 local->hw_scan_req->req.duration_mandatory =
609                         req->duration_mandatory;
610
611                 local->hw_scan_band = 0;
612
613                 /*
614                  * After allocating local->hw_scan_req, we must
615                  * go through until ieee80211_prep_hw_scan(), so
616                  * anything that might be changed here and leave
617                  * this function early must not go after this
618                  * allocation.
619                  */
620         }
621
622         rcu_assign_pointer(local->scan_req, req);
623         rcu_assign_pointer(local->scan_sdata, sdata);
624
625         if (req->flags & NL80211_SCAN_FLAG_RANDOM_ADDR)
626                 get_random_mask_addr(local->scan_addr,
627                                      req->mac_addr,
628                                      req->mac_addr_mask);
629         else
630                 memcpy(local->scan_addr, sdata->vif.addr, ETH_ALEN);
631
632         if (local->ops->hw_scan) {
633                 __set_bit(SCAN_HW_SCANNING, &local->scanning);
634         } else if ((req->n_channels == 1) &&
635                    (req->channels[0] == local->_oper_chandef.chan)) {
636                 /*
637                  * If we are scanning only on the operating channel
638                  * then we do not need to stop normal activities
639                  */
640                 unsigned long next_delay;
641
642                 __set_bit(SCAN_ONCHANNEL_SCANNING, &local->scanning);
643
644                 ieee80211_recalc_idle(local);
645
646                 /* Notify driver scan is starting, keep order of operations
647                  * same as normal software scan, in case that matters. */
648                 drv_sw_scan_start(local, sdata, local->scan_addr);
649
650                 ieee80211_configure_filter(local); /* accept probe-responses */
651
652                 /* We need to ensure power level is at max for scanning. */
653                 ieee80211_hw_config(local, 0);
654
655                 if ((req->channels[0]->flags & (IEEE80211_CHAN_NO_IR |
656                                                 IEEE80211_CHAN_RADAR)) ||
657                     !req->n_ssids) {
658                         next_delay = IEEE80211_PASSIVE_CHANNEL_TIME;
659                         if (req->n_ssids)
660                                 set_bit(SCAN_BEACON_WAIT, &local->scanning);
661                 } else {
662                         ieee80211_scan_state_send_probe(local, &next_delay);
663                         next_delay = IEEE80211_CHANNEL_TIME;
664                 }
665
666                 /* Now, just wait a bit and we are all done! */
667                 ieee80211_queue_delayed_work(&local->hw, &local->scan_work,
668                                              next_delay);
669                 return 0;
670         } else {
671                 /* Do normal software scan */
672                 __set_bit(SCAN_SW_SCANNING, &local->scanning);
673         }
674
675         ieee80211_recalc_idle(local);
676
677         if (local->ops->hw_scan) {
678                 WARN_ON(!ieee80211_prep_hw_scan(local));
679                 rc = drv_hw_scan(local, sdata, local->hw_scan_req);
680         } else {
681                 rc = ieee80211_start_sw_scan(local, sdata);
682         }
683
684         if (rc) {
685                 kfree(local->hw_scan_req);
686                 local->hw_scan_req = NULL;
687                 local->scanning = 0;
688
689                 ieee80211_recalc_idle(local);
690
691                 local->scan_req = NULL;
692                 RCU_INIT_POINTER(local->scan_sdata, NULL);
693         }
694
695         return rc;
696 }
697
698 static unsigned long
699 ieee80211_scan_get_channel_time(struct ieee80211_channel *chan)
700 {
701         /*
702          * TODO: channel switching also consumes quite some time,
703          * add that delay as well to get a better estimation
704          */
705         if (chan->flags & (IEEE80211_CHAN_NO_IR | IEEE80211_CHAN_RADAR))
706                 return IEEE80211_PASSIVE_CHANNEL_TIME;
707         return IEEE80211_PROBE_DELAY + IEEE80211_CHANNEL_TIME;
708 }
709
710 static void ieee80211_scan_state_decision(struct ieee80211_local *local,
711                                           unsigned long *next_delay)
712 {
713         bool associated = false;
714         bool tx_empty = true;
715         bool bad_latency;
716         struct ieee80211_sub_if_data *sdata;
717         struct ieee80211_channel *next_chan;
718         enum mac80211_scan_state next_scan_state;
719         struct cfg80211_scan_request *scan_req;
720
721         /*
722          * check if at least one STA interface is associated,
723          * check if at least one STA interface has pending tx frames
724          * and grab the lowest used beacon interval
725          */
726         mutex_lock(&local->iflist_mtx);
727         list_for_each_entry(sdata, &local->interfaces, list) {
728                 if (!ieee80211_sdata_running(sdata))
729                         continue;
730
731                 if (sdata->vif.type == NL80211_IFTYPE_STATION) {
732                         if (sdata->u.mgd.associated) {
733                                 associated = true;
734
735                                 if (!qdisc_all_tx_empty(sdata->dev)) {
736                                         tx_empty = false;
737                                         break;
738                                 }
739                         }
740                 }
741         }
742         mutex_unlock(&local->iflist_mtx);
743
744         scan_req = rcu_dereference_protected(local->scan_req,
745                                              lockdep_is_held(&local->mtx));
746
747         next_chan = scan_req->channels[local->scan_channel_idx];
748
749         /*
750          * we're currently scanning a different channel, let's
751          * see if we can scan another channel without interfering
752          * with the current traffic situation.
753          *
754          * Keep good latency, do not stay off-channel more than 125 ms.
755          */
756
757         bad_latency = time_after(jiffies +
758                                  ieee80211_scan_get_channel_time(next_chan),
759                                  local->leave_oper_channel_time + HZ / 8);
760
761         if (associated && !tx_empty) {
762                 if (scan_req->flags & NL80211_SCAN_FLAG_LOW_PRIORITY)
763                         next_scan_state = SCAN_ABORT;
764                 else
765                         next_scan_state = SCAN_SUSPEND;
766         } else if (associated && bad_latency) {
767                 next_scan_state = SCAN_SUSPEND;
768         } else {
769                 next_scan_state = SCAN_SET_CHANNEL;
770         }
771
772         local->next_scan_state = next_scan_state;
773
774         *next_delay = 0;
775 }
776
777 static void ieee80211_scan_state_set_channel(struct ieee80211_local *local,
778                                              unsigned long *next_delay)
779 {
780         int skip;
781         struct ieee80211_channel *chan;
782         enum nl80211_bss_scan_width oper_scan_width;
783         struct cfg80211_scan_request *scan_req;
784
785         scan_req = rcu_dereference_protected(local->scan_req,
786                                              lockdep_is_held(&local->mtx));
787
788         skip = 0;
789         chan = scan_req->channels[local->scan_channel_idx];
790
791         local->scan_chandef.chan = chan;
792         local->scan_chandef.center_freq1 = chan->center_freq;
793         local->scan_chandef.center_freq2 = 0;
794         switch (scan_req->scan_width) {
795         case NL80211_BSS_CHAN_WIDTH_5:
796                 local->scan_chandef.width = NL80211_CHAN_WIDTH_5;
797                 break;
798         case NL80211_BSS_CHAN_WIDTH_10:
799                 local->scan_chandef.width = NL80211_CHAN_WIDTH_10;
800                 break;
801         case NL80211_BSS_CHAN_WIDTH_20:
802                 /* If scanning on oper channel, use whatever channel-type
803                  * is currently in use.
804                  */
805                 oper_scan_width = cfg80211_chandef_to_scan_width(
806                                         &local->_oper_chandef);
807                 if (chan == local->_oper_chandef.chan &&
808                     oper_scan_width == scan_req->scan_width)
809                         local->scan_chandef = local->_oper_chandef;
810                 else
811                         local->scan_chandef.width = NL80211_CHAN_WIDTH_20_NOHT;
812                 break;
813         }
814
815         if (ieee80211_hw_config(local, IEEE80211_CONF_CHANGE_CHANNEL))
816                 skip = 1;
817
818         /* advance state machine to next channel/band */
819         local->scan_channel_idx++;
820
821         if (skip) {
822                 /* if we skip this channel return to the decision state */
823                 local->next_scan_state = SCAN_DECISION;
824                 return;
825         }
826
827         /*
828          * Probe delay is used to update the NAV, cf. 11.1.3.2.2
829          * (which unfortunately doesn't say _why_ step a) is done,
830          * but it waits for the probe delay or until a frame is
831          * received - and the received frame would update the NAV).
832          * For now, we do not support waiting until a frame is
833          * received.
834          *
835          * In any case, it is not necessary for a passive scan.
836          */
837         if ((chan->flags & (IEEE80211_CHAN_NO_IR | IEEE80211_CHAN_RADAR)) ||
838             !scan_req->n_ssids) {
839                 *next_delay = IEEE80211_PASSIVE_CHANNEL_TIME;
840                 local->next_scan_state = SCAN_DECISION;
841                 if (scan_req->n_ssids)
842                         set_bit(SCAN_BEACON_WAIT, &local->scanning);
843                 return;
844         }
845
846         /* active scan, send probes */
847         *next_delay = IEEE80211_PROBE_DELAY;
848         local->next_scan_state = SCAN_SEND_PROBE;
849 }
850
851 static void ieee80211_scan_state_suspend(struct ieee80211_local *local,
852                                          unsigned long *next_delay)
853 {
854         /* switch back to the operating channel */
855         local->scan_chandef.chan = NULL;
856         ieee80211_hw_config(local, IEEE80211_CONF_CHANGE_CHANNEL);
857
858         /* disable PS */
859         ieee80211_offchannel_return(local);
860
861         *next_delay = HZ / 5;
862         /* afterwards, resume scan & go to next channel */
863         local->next_scan_state = SCAN_RESUME;
864 }
865
866 static void ieee80211_scan_state_resume(struct ieee80211_local *local,
867                                         unsigned long *next_delay)
868 {
869         ieee80211_offchannel_stop_vifs(local);
870
871         if (local->ops->flush) {
872                 ieee80211_flush_queues(local, NULL, false);
873                 *next_delay = 0;
874         } else
875                 *next_delay = HZ / 10;
876
877         /* remember when we left the operating channel */
878         local->leave_oper_channel_time = jiffies;
879
880         /* advance to the next channel to be scanned */
881         local->next_scan_state = SCAN_SET_CHANNEL;
882 }
883
884 void ieee80211_scan_work(struct work_struct *work)
885 {
886         struct ieee80211_local *local =
887                 container_of(work, struct ieee80211_local, scan_work.work);
888         struct ieee80211_sub_if_data *sdata;
889         struct cfg80211_scan_request *scan_req;
890         unsigned long next_delay = 0;
891         bool aborted;
892
893         mutex_lock(&local->mtx);
894
895         if (!ieee80211_can_run_worker(local)) {
896                 aborted = true;
897                 goto out_complete;
898         }
899
900         sdata = rcu_dereference_protected(local->scan_sdata,
901                                           lockdep_is_held(&local->mtx));
902         scan_req = rcu_dereference_protected(local->scan_req,
903                                              lockdep_is_held(&local->mtx));
904
905         /* When scanning on-channel, the first-callback means completed. */
906         if (test_bit(SCAN_ONCHANNEL_SCANNING, &local->scanning)) {
907                 aborted = test_and_clear_bit(SCAN_ABORTED, &local->scanning);
908                 goto out_complete;
909         }
910
911         if (test_and_clear_bit(SCAN_COMPLETED, &local->scanning)) {
912                 aborted = test_and_clear_bit(SCAN_ABORTED, &local->scanning);
913                 goto out_complete;
914         }
915
916         if (!sdata || !scan_req)
917                 goto out;
918
919         if (!local->scanning) {
920                 int rc;
921
922                 RCU_INIT_POINTER(local->scan_req, NULL);
923                 RCU_INIT_POINTER(local->scan_sdata, NULL);
924
925                 rc = __ieee80211_start_scan(sdata, scan_req);
926                 if (rc) {
927                         /* need to complete scan in cfg80211 */
928                         rcu_assign_pointer(local->scan_req, scan_req);
929                         aborted = true;
930                         goto out_complete;
931                 } else
932                         goto out;
933         }
934
935         clear_bit(SCAN_BEACON_WAIT, &local->scanning);
936
937         /*
938          * as long as no delay is required advance immediately
939          * without scheduling a new work
940          */
941         do {
942                 if (!ieee80211_sdata_running(sdata)) {
943                         aborted = true;
944                         goto out_complete;
945                 }
946
947                 if (test_and_clear_bit(SCAN_BEACON_DONE, &local->scanning) &&
948                     local->next_scan_state == SCAN_DECISION)
949                         local->next_scan_state = SCAN_SEND_PROBE;
950
951                 switch (local->next_scan_state) {
952                 case SCAN_DECISION:
953                         /* if no more bands/channels left, complete scan */
954                         if (local->scan_channel_idx >= scan_req->n_channels) {
955                                 aborted = false;
956                                 goto out_complete;
957                         }
958                         ieee80211_scan_state_decision(local, &next_delay);
959                         break;
960                 case SCAN_SET_CHANNEL:
961                         ieee80211_scan_state_set_channel(local, &next_delay);
962                         break;
963                 case SCAN_SEND_PROBE:
964                         ieee80211_scan_state_send_probe(local, &next_delay);
965                         break;
966                 case SCAN_SUSPEND:
967                         ieee80211_scan_state_suspend(local, &next_delay);
968                         break;
969                 case SCAN_RESUME:
970                         ieee80211_scan_state_resume(local, &next_delay);
971                         break;
972                 case SCAN_ABORT:
973                         aborted = true;
974                         goto out_complete;
975                 }
976         } while (next_delay == 0);
977
978         ieee80211_queue_delayed_work(&local->hw, &local->scan_work, next_delay);
979         goto out;
980
981 out_complete:
982         __ieee80211_scan_completed(&local->hw, aborted);
983 out:
984         mutex_unlock(&local->mtx);
985 }
986
987 int ieee80211_request_scan(struct ieee80211_sub_if_data *sdata,
988                            struct cfg80211_scan_request *req)
989 {
990         int res;
991
992         mutex_lock(&sdata->local->mtx);
993         res = __ieee80211_start_scan(sdata, req);
994         mutex_unlock(&sdata->local->mtx);
995
996         return res;
997 }
998
999 int ieee80211_request_ibss_scan(struct ieee80211_sub_if_data *sdata,
1000                                 const u8 *ssid, u8 ssid_len,
1001                                 struct ieee80211_channel **channels,
1002                                 unsigned int n_channels,
1003                                 enum nl80211_bss_scan_width scan_width)
1004 {
1005         struct ieee80211_local *local = sdata->local;
1006         int ret = -EBUSY, i, n_ch = 0;
1007         enum nl80211_band band;
1008
1009         mutex_lock(&local->mtx);
1010
1011         /* busy scanning */
1012         if (local->scan_req)
1013                 goto unlock;
1014
1015         /* fill internal scan request */
1016         if (!channels) {
1017                 int max_n;
1018
1019                 for (band = 0; band < NUM_NL80211_BANDS; band++) {
1020                         if (!local->hw.wiphy->bands[band])
1021                                 continue;
1022
1023                         max_n = local->hw.wiphy->bands[band]->n_channels;
1024                         for (i = 0; i < max_n; i++) {
1025                                 struct ieee80211_channel *tmp_ch =
1026                                     &local->hw.wiphy->bands[band]->channels[i];
1027
1028                                 if (tmp_ch->flags & (IEEE80211_CHAN_NO_IR |
1029                                                      IEEE80211_CHAN_DISABLED))
1030                                         continue;
1031
1032                                 local->int_scan_req->channels[n_ch] = tmp_ch;
1033                                 n_ch++;
1034                         }
1035                 }
1036
1037                 if (WARN_ON_ONCE(n_ch == 0))
1038                         goto unlock;
1039
1040                 local->int_scan_req->n_channels = n_ch;
1041         } else {
1042                 for (i = 0; i < n_channels; i++) {
1043                         if (channels[i]->flags & (IEEE80211_CHAN_NO_IR |
1044                                                   IEEE80211_CHAN_DISABLED))
1045                                 continue;
1046
1047                         local->int_scan_req->channels[n_ch] = channels[i];
1048                         n_ch++;
1049                 }
1050
1051                 if (WARN_ON_ONCE(n_ch == 0))
1052                         goto unlock;
1053
1054                 local->int_scan_req->n_channels = n_ch;
1055         }
1056
1057         local->int_scan_req->ssids = &local->scan_ssid;
1058         local->int_scan_req->n_ssids = 1;
1059         local->int_scan_req->scan_width = scan_width;
1060         memcpy(local->int_scan_req->ssids[0].ssid, ssid, IEEE80211_MAX_SSID_LEN);
1061         local->int_scan_req->ssids[0].ssid_len = ssid_len;
1062
1063         ret = __ieee80211_start_scan(sdata, sdata->local->int_scan_req);
1064  unlock:
1065         mutex_unlock(&local->mtx);
1066         return ret;
1067 }
1068
1069 /*
1070  * Only call this function when a scan can't be queued -- under RTNL.
1071  */
1072 void ieee80211_scan_cancel(struct ieee80211_local *local)
1073 {
1074         /*
1075          * We are canceling software scan, or deferred scan that was not
1076          * yet really started (see __ieee80211_start_scan ).
1077          *
1078          * Regarding hardware scan:
1079          * - we can not call  __ieee80211_scan_completed() as when
1080          *   SCAN_HW_SCANNING bit is set this function change
1081          *   local->hw_scan_req to operate on 5G band, what race with
1082          *   driver which can use local->hw_scan_req
1083          *
1084          * - we can not cancel scan_work since driver can schedule it
1085          *   by ieee80211_scan_completed(..., true) to finish scan
1086          *
1087          * Hence we only call the cancel_hw_scan() callback, but the low-level
1088          * driver is still responsible for calling ieee80211_scan_completed()
1089          * after the scan was completed/aborted.
1090          */
1091
1092         mutex_lock(&local->mtx);
1093         if (!local->scan_req)
1094                 goto out;
1095
1096         /*
1097          * We have a scan running and the driver already reported completion,
1098          * but the worker hasn't run yet or is stuck on the mutex - mark it as
1099          * cancelled.
1100          */
1101         if (test_bit(SCAN_HW_SCANNING, &local->scanning) &&
1102             test_bit(SCAN_COMPLETED, &local->scanning)) {
1103                 set_bit(SCAN_HW_CANCELLED, &local->scanning);
1104                 goto out;
1105         }
1106
1107         if (test_bit(SCAN_HW_SCANNING, &local->scanning)) {
1108                 /*
1109                  * Make sure that __ieee80211_scan_completed doesn't trigger a
1110                  * scan on another band.
1111                  */
1112                 set_bit(SCAN_HW_CANCELLED, &local->scanning);
1113                 if (local->ops->cancel_hw_scan)
1114                         drv_cancel_hw_scan(local,
1115                                 rcu_dereference_protected(local->scan_sdata,
1116                                                 lockdep_is_held(&local->mtx)));
1117                 goto out;
1118         }
1119
1120         /*
1121          * If the work is currently running, it must be blocked on
1122          * the mutex, but we'll set scan_sdata = NULL and it'll
1123          * simply exit once it acquires the mutex.
1124          */
1125         cancel_delayed_work(&local->scan_work);
1126         /* and clean up */
1127         memset(&local->scan_info, 0, sizeof(local->scan_info));
1128         __ieee80211_scan_completed(&local->hw, true);
1129 out:
1130         mutex_unlock(&local->mtx);
1131 }
1132
1133 int __ieee80211_request_sched_scan_start(struct ieee80211_sub_if_data *sdata,
1134                                         struct cfg80211_sched_scan_request *req)
1135 {
1136         struct ieee80211_local *local = sdata->local;
1137         struct ieee80211_scan_ies sched_scan_ies = {};
1138         struct cfg80211_chan_def chandef;
1139         int ret, i, iebufsz, num_bands = 0;
1140         u32 rate_masks[NUM_NL80211_BANDS] = {};
1141         u8 bands_used = 0;
1142         u8 *ie;
1143
1144         iebufsz = local->scan_ies_len + req->ie_len;
1145
1146         lockdep_assert_held(&local->mtx);
1147
1148         if (!local->ops->sched_scan_start)
1149                 return -ENOTSUPP;
1150
1151         for (i = 0; i < NUM_NL80211_BANDS; i++) {
1152                 if (local->hw.wiphy->bands[i]) {
1153                         bands_used |= BIT(i);
1154                         rate_masks[i] = (u32) -1;
1155                         num_bands++;
1156                 }
1157         }
1158
1159         ie = kzalloc(num_bands * iebufsz, GFP_KERNEL);
1160         if (!ie) {
1161                 ret = -ENOMEM;
1162                 goto out;
1163         }
1164
1165         ieee80211_prepare_scan_chandef(&chandef, req->scan_width);
1166
1167         ieee80211_build_preq_ies(local, ie, num_bands * iebufsz,
1168                                  &sched_scan_ies, req->ie,
1169                                  req->ie_len, bands_used, rate_masks, &chandef);
1170
1171         ret = drv_sched_scan_start(local, sdata, req, &sched_scan_ies);
1172         if (ret == 0) {
1173                 rcu_assign_pointer(local->sched_scan_sdata, sdata);
1174                 rcu_assign_pointer(local->sched_scan_req, req);
1175         }
1176
1177         kfree(ie);
1178
1179 out:
1180         if (ret) {
1181                 /* Clean in case of failure after HW restart or upon resume. */
1182                 RCU_INIT_POINTER(local->sched_scan_sdata, NULL);
1183                 RCU_INIT_POINTER(local->sched_scan_req, NULL);
1184         }
1185
1186         return ret;
1187 }
1188
1189 int ieee80211_request_sched_scan_start(struct ieee80211_sub_if_data *sdata,
1190                                        struct cfg80211_sched_scan_request *req)
1191 {
1192         struct ieee80211_local *local = sdata->local;
1193         int ret;
1194
1195         mutex_lock(&local->mtx);
1196
1197         if (rcu_access_pointer(local->sched_scan_sdata)) {
1198                 mutex_unlock(&local->mtx);
1199                 return -EBUSY;
1200         }
1201
1202         ret = __ieee80211_request_sched_scan_start(sdata, req);
1203
1204         mutex_unlock(&local->mtx);
1205         return ret;
1206 }
1207
1208 int ieee80211_request_sched_scan_stop(struct ieee80211_local *local)
1209 {
1210         struct ieee80211_sub_if_data *sched_scan_sdata;
1211         int ret = -ENOENT;
1212
1213         mutex_lock(&local->mtx);
1214
1215         if (!local->ops->sched_scan_stop) {
1216                 ret = -ENOTSUPP;
1217                 goto out;
1218         }
1219
1220         /* We don't want to restart sched scan anymore. */
1221         RCU_INIT_POINTER(local->sched_scan_req, NULL);
1222
1223         sched_scan_sdata = rcu_dereference_protected(local->sched_scan_sdata,
1224                                                 lockdep_is_held(&local->mtx));
1225         if (sched_scan_sdata) {
1226                 ret = drv_sched_scan_stop(local, sched_scan_sdata);
1227                 if (!ret)
1228                         RCU_INIT_POINTER(local->sched_scan_sdata, NULL);
1229         }
1230 out:
1231         mutex_unlock(&local->mtx);
1232
1233         return ret;
1234 }
1235
1236 void ieee80211_sched_scan_results(struct ieee80211_hw *hw)
1237 {
1238         struct ieee80211_local *local = hw_to_local(hw);
1239
1240         trace_api_sched_scan_results(local);
1241
1242         cfg80211_sched_scan_results(hw->wiphy, 0);
1243 }
1244 EXPORT_SYMBOL(ieee80211_sched_scan_results);
1245
1246 void ieee80211_sched_scan_end(struct ieee80211_local *local)
1247 {
1248         mutex_lock(&local->mtx);
1249
1250         if (!rcu_access_pointer(local->sched_scan_sdata)) {
1251                 mutex_unlock(&local->mtx);
1252                 return;
1253         }
1254
1255         RCU_INIT_POINTER(local->sched_scan_sdata, NULL);
1256
1257         /* If sched scan was aborted by the driver. */
1258         RCU_INIT_POINTER(local->sched_scan_req, NULL);
1259
1260         mutex_unlock(&local->mtx);
1261
1262         cfg80211_sched_scan_stopped(local->hw.wiphy, 0);
1263 }
1264
1265 void ieee80211_sched_scan_stopped_work(struct work_struct *work)
1266 {
1267         struct ieee80211_local *local =
1268                 container_of(work, struct ieee80211_local,
1269                              sched_scan_stopped_work);
1270
1271         ieee80211_sched_scan_end(local);
1272 }
1273
1274 void ieee80211_sched_scan_stopped(struct ieee80211_hw *hw)
1275 {
1276         struct ieee80211_local *local = hw_to_local(hw);
1277
1278         trace_api_sched_scan_stopped(local);
1279
1280         /*
1281          * this shouldn't really happen, so for simplicity
1282          * simply ignore it, and let mac80211 reconfigure
1283          * the sched scan later on.
1284          */
1285         if (local->in_reconfig)
1286                 return;
1287
1288         schedule_work(&local->sched_scan_stopped_work);
1289 }
1290 EXPORT_SYMBOL(ieee80211_sched_scan_stopped);