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Merge tag 'rtc-4.6-2' of git://git.kernel.org/pub/scm/linux/kernel/git/abelloni/linux
[deliverable/linux.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 *
11 * This program is free software; you can redistribute it and/or modify
12 * it under the terms of the GNU General Public License version 2 as
13 * published by the Free Software Foundation.
14 */
15
16 #include <linux/if_arp.h>
17 #include <linux/etherdevice.h>
18 #include <linux/rtnetlink.h>
19 #include <net/sch_generic.h>
20 #include <linux/slab.h>
21 #include <linux/export.h>
22 #include <net/mac80211.h>
23
24 #include "ieee80211_i.h"
25 #include "driver-ops.h"
26 #include "mesh.h"
27
28 #define IEEE80211_PROBE_DELAY (HZ / 33)
29 #define IEEE80211_CHANNEL_TIME (HZ / 33)
30 #define IEEE80211_PASSIVE_CHANNEL_TIME (HZ / 9)
31
32 void ieee80211_rx_bss_put(struct ieee80211_local *local,
33 struct ieee80211_bss *bss)
34 {
35 if (!bss)
36 return;
37 cfg80211_put_bss(local->hw.wiphy,
38 container_of((void *)bss, struct cfg80211_bss, priv));
39 }
40
41 static bool is_uapsd_supported(struct ieee802_11_elems *elems)
42 {
43 u8 qos_info;
44
45 if (elems->wmm_info && elems->wmm_info_len == 7
46 && elems->wmm_info[5] == 1)
47 qos_info = elems->wmm_info[6];
48 else if (elems->wmm_param && elems->wmm_param_len == 24
49 && elems->wmm_param[5] == 1)
50 qos_info = elems->wmm_param[6];
51 else
52 /* no valid wmm information or parameter element found */
53 return false;
54
55 return qos_info & IEEE80211_WMM_IE_AP_QOSINFO_UAPSD;
56 }
57
58 struct ieee80211_bss *
59 ieee80211_bss_info_update(struct ieee80211_local *local,
60 struct ieee80211_rx_status *rx_status,
61 struct ieee80211_mgmt *mgmt, size_t len,
62 struct ieee802_11_elems *elems,
63 struct ieee80211_channel *channel)
64 {
65 bool beacon = ieee80211_is_beacon(mgmt->frame_control);
66 struct cfg80211_bss *cbss;
67 struct ieee80211_bss *bss;
68 int clen, srlen;
69 struct cfg80211_inform_bss bss_meta = {};
70 bool signal_valid;
71
72 if (ieee80211_hw_check(&local->hw, SIGNAL_DBM))
73 bss_meta.signal = rx_status->signal * 100;
74 else if (ieee80211_hw_check(&local->hw, SIGNAL_UNSPEC))
75 bss_meta.signal = (rx_status->signal * 100) / local->hw.max_signal;
76
77 bss_meta.scan_width = NL80211_BSS_CHAN_WIDTH_20;
78 if (rx_status->flag & RX_FLAG_5MHZ)
79 bss_meta.scan_width = NL80211_BSS_CHAN_WIDTH_5;
80 if (rx_status->flag & RX_FLAG_10MHZ)
81 bss_meta.scan_width = NL80211_BSS_CHAN_WIDTH_10;
82
83 bss_meta.chan = channel;
84 cbss = cfg80211_inform_bss_frame_data(local->hw.wiphy, &bss_meta,
85 mgmt, len, GFP_ATOMIC);
86 if (!cbss)
87 return NULL;
88 /* In case the signal is invalid update the status */
89 signal_valid = abs(channel->center_freq - cbss->channel->center_freq)
90 <= local->hw.wiphy->max_adj_channel_rssi_comp;
91 if (!signal_valid)
92 rx_status->flag |= RX_FLAG_NO_SIGNAL_VAL;
93
94 bss = (void *)cbss->priv;
95
96 if (beacon)
97 bss->device_ts_beacon = rx_status->device_timestamp;
98 else
99 bss->device_ts_presp = rx_status->device_timestamp;
100
101 if (elems->parse_error) {
102 if (beacon)
103 bss->corrupt_data |= IEEE80211_BSS_CORRUPT_BEACON;
104 else
105 bss->corrupt_data |= IEEE80211_BSS_CORRUPT_PROBE_RESP;
106 } else {
107 if (beacon)
108 bss->corrupt_data &= ~IEEE80211_BSS_CORRUPT_BEACON;
109 else
110 bss->corrupt_data &= ~IEEE80211_BSS_CORRUPT_PROBE_RESP;
111 }
112
113 /* save the ERP value so that it is available at association time */
114 if (elems->erp_info && (!elems->parse_error ||
115 !(bss->valid_data & IEEE80211_BSS_VALID_ERP))) {
116 bss->erp_value = elems->erp_info[0];
117 bss->has_erp_value = true;
118 if (!elems->parse_error)
119 bss->valid_data |= IEEE80211_BSS_VALID_ERP;
120 }
121
122 /* replace old supported rates if we get new values */
123 if (!elems->parse_error ||
124 !(bss->valid_data & IEEE80211_BSS_VALID_RATES)) {
125 srlen = 0;
126 if (elems->supp_rates) {
127 clen = IEEE80211_MAX_SUPP_RATES;
128 if (clen > elems->supp_rates_len)
129 clen = elems->supp_rates_len;
130 memcpy(bss->supp_rates, elems->supp_rates, clen);
131 srlen += clen;
132 }
133 if (elems->ext_supp_rates) {
134 clen = IEEE80211_MAX_SUPP_RATES - srlen;
135 if (clen > elems->ext_supp_rates_len)
136 clen = elems->ext_supp_rates_len;
137 memcpy(bss->supp_rates + srlen, elems->ext_supp_rates,
138 clen);
139 srlen += clen;
140 }
141 if (srlen) {
142 bss->supp_rates_len = srlen;
143 if (!elems->parse_error)
144 bss->valid_data |= IEEE80211_BSS_VALID_RATES;
145 }
146 }
147
148 if (!elems->parse_error ||
149 !(bss->valid_data & IEEE80211_BSS_VALID_WMM)) {
150 bss->wmm_used = elems->wmm_param || elems->wmm_info;
151 bss->uapsd_supported = is_uapsd_supported(elems);
152 if (!elems->parse_error)
153 bss->valid_data |= IEEE80211_BSS_VALID_WMM;
154 }
155
156 if (beacon) {
157 struct ieee80211_supported_band *sband =
158 local->hw.wiphy->bands[rx_status->band];
159 if (!(rx_status->flag & RX_FLAG_HT) &&
160 !(rx_status->flag & RX_FLAG_VHT))
161 bss->beacon_rate =
162 &sband->bitrates[rx_status->rate_idx];
163 }
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 struct ieee802_11_elems elems;
178
179 if (skb->len < 24 ||
180 (!ieee80211_is_probe_resp(mgmt->frame_control) &&
181 !ieee80211_is_beacon(mgmt->frame_control)))
182 return;
183
184 sdata1 = rcu_dereference(local->scan_sdata);
185 sdata2 = rcu_dereference(local->sched_scan_sdata);
186
187 if (likely(!sdata1 && !sdata2))
188 return;
189
190 if (ieee80211_is_probe_resp(mgmt->frame_control)) {
191 struct cfg80211_scan_request *scan_req;
192 struct cfg80211_sched_scan_request *sched_scan_req;
193
194 scan_req = rcu_dereference(local->scan_req);
195 sched_scan_req = rcu_dereference(local->sched_scan_req);
196
197 /* ignore ProbeResp to foreign address unless scanning
198 * with randomised address
199 */
200 if (!(sdata1 &&
201 (ether_addr_equal(mgmt->da, sdata1->vif.addr) ||
202 scan_req->flags & NL80211_SCAN_FLAG_RANDOM_ADDR)) &&
203 !(sdata2 &&
204 (ether_addr_equal(mgmt->da, sdata2->vif.addr) ||
205 sched_scan_req->flags & NL80211_SCAN_FLAG_RANDOM_ADDR)))
206 return;
207
208 elements = mgmt->u.probe_resp.variable;
209 baselen = offsetof(struct ieee80211_mgmt, u.probe_resp.variable);
210 } else {
211 baselen = offsetof(struct ieee80211_mgmt, u.beacon.variable);
212 elements = mgmt->u.beacon.variable;
213 }
214
215 if (baselen > skb->len)
216 return;
217
218 ieee802_11_parse_elems(elements, skb->len - baselen, false, &elems);
219
220 channel = ieee80211_get_channel(local->hw.wiphy, rx_status->freq);
221
222 if (!channel || channel->flags & IEEE80211_CHAN_DISABLED)
223 return;
224
225 bss = ieee80211_bss_info_update(local, rx_status,
226 mgmt, skb->len, &elems,
227 channel);
228 if (bss)
229 ieee80211_rx_bss_put(local, bss);
230 }
231
232 static void
233 ieee80211_prepare_scan_chandef(struct cfg80211_chan_def *chandef,
234 enum nl80211_bss_scan_width scan_width)
235 {
236 memset(chandef, 0, sizeof(*chandef));
237 switch (scan_width) {
238 case NL80211_BSS_CHAN_WIDTH_5:
239 chandef->width = NL80211_CHAN_WIDTH_5;
240 break;
241 case NL80211_BSS_CHAN_WIDTH_10:
242 chandef->width = NL80211_CHAN_WIDTH_10;
243 break;
244 default:
245 chandef->width = NL80211_CHAN_WIDTH_20_NOHT;
246 break;
247 }
248 }
249
250 /* return false if no more work */
251 static bool ieee80211_prep_hw_scan(struct ieee80211_local *local)
252 {
253 struct cfg80211_scan_request *req;
254 struct cfg80211_chan_def chandef;
255 u8 bands_used = 0;
256 int i, ielen, n_chans;
257
258 req = rcu_dereference_protected(local->scan_req,
259 lockdep_is_held(&local->mtx));
260
261 if (test_bit(SCAN_HW_CANCELLED, &local->scanning))
262 return false;
263
264 if (ieee80211_hw_check(&local->hw, SINGLE_SCAN_ON_ALL_BANDS)) {
265 for (i = 0; i < req->n_channels; i++) {
266 local->hw_scan_req->req.channels[i] = req->channels[i];
267 bands_used |= BIT(req->channels[i]->band);
268 }
269
270 n_chans = req->n_channels;
271 } else {
272 do {
273 if (local->hw_scan_band == IEEE80211_NUM_BANDS)
274 return false;
275
276 n_chans = 0;
277
278 for (i = 0; i < req->n_channels; i++) {
279 if (req->channels[i]->band !=
280 local->hw_scan_band)
281 continue;
282 local->hw_scan_req->req.channels[n_chans] =
283 req->channels[i];
284 n_chans++;
285 bands_used |= BIT(req->channels[i]->band);
286 }
287
288 local->hw_scan_band++;
289 } while (!n_chans);
290 }
291
292 local->hw_scan_req->req.n_channels = n_chans;
293 ieee80211_prepare_scan_chandef(&chandef, req->scan_width);
294
295 ielen = ieee80211_build_preq_ies(local,
296 (u8 *)local->hw_scan_req->req.ie,
297 local->hw_scan_ies_bufsize,
298 &local->hw_scan_req->ies,
299 req->ie, req->ie_len,
300 bands_used, req->rates, &chandef);
301 local->hw_scan_req->req.ie_len = ielen;
302 local->hw_scan_req->req.no_cck = req->no_cck;
303 ether_addr_copy(local->hw_scan_req->req.mac_addr, req->mac_addr);
304 ether_addr_copy(local->hw_scan_req->req.mac_addr_mask,
305 req->mac_addr_mask);
306
307 return true;
308 }
309
310 static void __ieee80211_scan_completed(struct ieee80211_hw *hw, bool aborted)
311 {
312 struct ieee80211_local *local = hw_to_local(hw);
313 bool hw_scan = local->ops->hw_scan;
314 bool was_scanning = local->scanning;
315 struct cfg80211_scan_request *scan_req;
316 struct ieee80211_sub_if_data *scan_sdata;
317 struct ieee80211_sub_if_data *sdata;
318
319 lockdep_assert_held(&local->mtx);
320
321 /*
322 * It's ok to abort a not-yet-running scan (that
323 * we have one at all will be verified by checking
324 * local->scan_req next), but not to complete it
325 * successfully.
326 */
327 if (WARN_ON(!local->scanning && !aborted))
328 aborted = true;
329
330 if (WARN_ON(!local->scan_req))
331 return;
332
333 if (hw_scan && !aborted &&
334 !ieee80211_hw_check(&local->hw, SINGLE_SCAN_ON_ALL_BANDS) &&
335 ieee80211_prep_hw_scan(local)) {
336 int rc;
337
338 rc = drv_hw_scan(local,
339 rcu_dereference_protected(local->scan_sdata,
340 lockdep_is_held(&local->mtx)),
341 local->hw_scan_req);
342
343 if (rc == 0)
344 return;
345 }
346
347 kfree(local->hw_scan_req);
348 local->hw_scan_req = NULL;
349
350 scan_req = rcu_dereference_protected(local->scan_req,
351 lockdep_is_held(&local->mtx));
352
353 if (scan_req != local->int_scan_req)
354 cfg80211_scan_done(scan_req, aborted);
355 RCU_INIT_POINTER(local->scan_req, NULL);
356
357 scan_sdata = rcu_dereference_protected(local->scan_sdata,
358 lockdep_is_held(&local->mtx));
359 RCU_INIT_POINTER(local->scan_sdata, NULL);
360
361 local->scanning = 0;
362 local->scan_chandef.chan = NULL;
363
364 /* Set power back to normal operating levels. */
365 ieee80211_hw_config(local, 0);
366
367 if (!hw_scan) {
368 ieee80211_configure_filter(local);
369 drv_sw_scan_complete(local, scan_sdata);
370 ieee80211_offchannel_return(local);
371 }
372
373 ieee80211_recalc_idle(local);
374
375 ieee80211_mlme_notify_scan_completed(local);
376 ieee80211_ibss_notify_scan_completed(local);
377
378 /* Requeue all the work that might have been ignored while
379 * the scan was in progress; if there was none this will
380 * just be a no-op for the particular interface.
381 */
382 list_for_each_entry_rcu(sdata, &local->interfaces, list) {
383 if (ieee80211_sdata_running(sdata))
384 ieee80211_queue_work(&sdata->local->hw, &sdata->work);
385 }
386
387 if (was_scanning)
388 ieee80211_start_next_roc(local);
389 }
390
391 void ieee80211_scan_completed(struct ieee80211_hw *hw, bool aborted)
392 {
393 struct ieee80211_local *local = hw_to_local(hw);
394
395 trace_api_scan_completed(local, aborted);
396
397 set_bit(SCAN_COMPLETED, &local->scanning);
398 if (aborted)
399 set_bit(SCAN_ABORTED, &local->scanning);
400 ieee80211_queue_delayed_work(&local->hw, &local->scan_work, 0);
401 }
402 EXPORT_SYMBOL(ieee80211_scan_completed);
403
404 static int ieee80211_start_sw_scan(struct ieee80211_local *local,
405 struct ieee80211_sub_if_data *sdata)
406 {
407 /* Software scan is not supported in multi-channel cases */
408 if (local->use_chanctx)
409 return -EOPNOTSUPP;
410
411 /*
412 * Hardware/driver doesn't support hw_scan, so use software
413 * scanning instead. First send a nullfunc frame with power save
414 * bit on so that AP will buffer the frames for us while we are not
415 * listening, then send probe requests to each channel and wait for
416 * the responses. After all channels are scanned, tune back to the
417 * original channel and send a nullfunc frame with power save bit
418 * off to trigger the AP to send us all the buffered frames.
419 *
420 * Note that while local->sw_scanning is true everything else but
421 * nullfunc frames and probe requests will be dropped in
422 * ieee80211_tx_h_check_assoc().
423 */
424 drv_sw_scan_start(local, sdata, local->scan_addr);
425
426 local->leave_oper_channel_time = jiffies;
427 local->next_scan_state = SCAN_DECISION;
428 local->scan_channel_idx = 0;
429
430 ieee80211_offchannel_stop_vifs(local);
431
432 /* ensure nullfunc is transmitted before leaving operating channel */
433 ieee80211_flush_queues(local, NULL, false);
434
435 ieee80211_configure_filter(local);
436
437 /* We need to set power level at maximum rate for scanning. */
438 ieee80211_hw_config(local, 0);
439
440 ieee80211_queue_delayed_work(&local->hw,
441 &local->scan_work, 0);
442
443 return 0;
444 }
445
446 static bool ieee80211_can_scan(struct ieee80211_local *local,
447 struct ieee80211_sub_if_data *sdata)
448 {
449 if (ieee80211_is_radar_required(local))
450 return false;
451
452 if (!list_empty(&local->roc_list))
453 return false;
454
455 if (sdata->vif.type == NL80211_IFTYPE_STATION &&
456 sdata->u.mgd.flags & IEEE80211_STA_CONNECTION_POLL)
457 return false;
458
459 return true;
460 }
461
462 void ieee80211_run_deferred_scan(struct ieee80211_local *local)
463 {
464 lockdep_assert_held(&local->mtx);
465
466 if (!local->scan_req || local->scanning)
467 return;
468
469 if (!ieee80211_can_scan(local,
470 rcu_dereference_protected(
471 local->scan_sdata,
472 lockdep_is_held(&local->mtx))))
473 return;
474
475 ieee80211_queue_delayed_work(&local->hw, &local->scan_work,
476 round_jiffies_relative(0));
477 }
478
479 static void ieee80211_scan_state_send_probe(struct ieee80211_local *local,
480 unsigned long *next_delay)
481 {
482 int i;
483 struct ieee80211_sub_if_data *sdata;
484 struct cfg80211_scan_request *scan_req;
485 enum ieee80211_band band = local->hw.conf.chandef.chan->band;
486 u32 tx_flags;
487
488 scan_req = rcu_dereference_protected(local->scan_req,
489 lockdep_is_held(&local->mtx));
490
491 tx_flags = IEEE80211_TX_INTFL_OFFCHAN_TX_OK;
492 if (scan_req->no_cck)
493 tx_flags |= IEEE80211_TX_CTL_NO_CCK_RATE;
494
495 sdata = rcu_dereference_protected(local->scan_sdata,
496 lockdep_is_held(&local->mtx));
497
498 for (i = 0; i < scan_req->n_ssids; i++)
499 ieee80211_send_probe_req(
500 sdata, local->scan_addr, NULL,
501 scan_req->ssids[i].ssid, scan_req->ssids[i].ssid_len,
502 scan_req->ie, scan_req->ie_len,
503 scan_req->rates[band], false,
504 tx_flags, local->hw.conf.chandef.chan, true);
505
506 /*
507 * After sending probe requests, wait for probe responses
508 * on the channel.
509 */
510 *next_delay = IEEE80211_CHANNEL_TIME;
511 local->next_scan_state = SCAN_DECISION;
512 }
513
514 static int __ieee80211_start_scan(struct ieee80211_sub_if_data *sdata,
515 struct cfg80211_scan_request *req)
516 {
517 struct ieee80211_local *local = sdata->local;
518 int rc;
519
520 lockdep_assert_held(&local->mtx);
521
522 if (local->scan_req || ieee80211_is_radar_required(local))
523 return -EBUSY;
524
525 if (!ieee80211_can_scan(local, sdata)) {
526 /* wait for the work to finish/time out */
527 rcu_assign_pointer(local->scan_req, req);
528 rcu_assign_pointer(local->scan_sdata, sdata);
529 return 0;
530 }
531
532 if (local->ops->hw_scan) {
533 u8 *ies;
534
535 local->hw_scan_ies_bufsize = local->scan_ies_len + req->ie_len;
536
537 if (ieee80211_hw_check(&local->hw, SINGLE_SCAN_ON_ALL_BANDS)) {
538 int i, n_bands = 0;
539 u8 bands_counted = 0;
540
541 for (i = 0; i < req->n_channels; i++) {
542 if (bands_counted & BIT(req->channels[i]->band))
543 continue;
544 bands_counted |= BIT(req->channels[i]->band);
545 n_bands++;
546 }
547
548 local->hw_scan_ies_bufsize *= n_bands;
549 }
550
551 local->hw_scan_req = kmalloc(
552 sizeof(*local->hw_scan_req) +
553 req->n_channels * sizeof(req->channels[0]) +
554 local->hw_scan_ies_bufsize, GFP_KERNEL);
555 if (!local->hw_scan_req)
556 return -ENOMEM;
557
558 local->hw_scan_req->req.ssids = req->ssids;
559 local->hw_scan_req->req.n_ssids = req->n_ssids;
560 ies = (u8 *)local->hw_scan_req +
561 sizeof(*local->hw_scan_req) +
562 req->n_channels * sizeof(req->channels[0]);
563 local->hw_scan_req->req.ie = ies;
564 local->hw_scan_req->req.flags = req->flags;
565
566 local->hw_scan_band = 0;
567
568 /*
569 * After allocating local->hw_scan_req, we must
570 * go through until ieee80211_prep_hw_scan(), so
571 * anything that might be changed here and leave
572 * this function early must not go after this
573 * allocation.
574 */
575 }
576
577 rcu_assign_pointer(local->scan_req, req);
578 rcu_assign_pointer(local->scan_sdata, sdata);
579
580 if (req->flags & NL80211_SCAN_FLAG_RANDOM_ADDR)
581 get_random_mask_addr(local->scan_addr,
582 req->mac_addr,
583 req->mac_addr_mask);
584 else
585 memcpy(local->scan_addr, sdata->vif.addr, ETH_ALEN);
586
587 if (local->ops->hw_scan) {
588 __set_bit(SCAN_HW_SCANNING, &local->scanning);
589 } else if ((req->n_channels == 1) &&
590 (req->channels[0] == local->_oper_chandef.chan)) {
591 /*
592 * If we are scanning only on the operating channel
593 * then we do not need to stop normal activities
594 */
595 unsigned long next_delay;
596
597 __set_bit(SCAN_ONCHANNEL_SCANNING, &local->scanning);
598
599 ieee80211_recalc_idle(local);
600
601 /* Notify driver scan is starting, keep order of operations
602 * same as normal software scan, in case that matters. */
603 drv_sw_scan_start(local, sdata, local->scan_addr);
604
605 ieee80211_configure_filter(local); /* accept probe-responses */
606
607 /* We need to ensure power level is at max for scanning. */
608 ieee80211_hw_config(local, 0);
609
610 if ((req->channels[0]->flags & (IEEE80211_CHAN_NO_IR |
611 IEEE80211_CHAN_RADAR)) ||
612 !req->n_ssids) {
613 next_delay = IEEE80211_PASSIVE_CHANNEL_TIME;
614 } else {
615 ieee80211_scan_state_send_probe(local, &next_delay);
616 next_delay = IEEE80211_CHANNEL_TIME;
617 }
618
619 /* Now, just wait a bit and we are all done! */
620 ieee80211_queue_delayed_work(&local->hw, &local->scan_work,
621 next_delay);
622 return 0;
623 } else {
624 /* Do normal software scan */
625 __set_bit(SCAN_SW_SCANNING, &local->scanning);
626 }
627
628 ieee80211_recalc_idle(local);
629
630 if (local->ops->hw_scan) {
631 WARN_ON(!ieee80211_prep_hw_scan(local));
632 rc = drv_hw_scan(local, sdata, local->hw_scan_req);
633 } else {
634 rc = ieee80211_start_sw_scan(local, sdata);
635 }
636
637 if (rc) {
638 kfree(local->hw_scan_req);
639 local->hw_scan_req = NULL;
640 local->scanning = 0;
641
642 ieee80211_recalc_idle(local);
643
644 local->scan_req = NULL;
645 RCU_INIT_POINTER(local->scan_sdata, NULL);
646 }
647
648 return rc;
649 }
650
651 static unsigned long
652 ieee80211_scan_get_channel_time(struct ieee80211_channel *chan)
653 {
654 /*
655 * TODO: channel switching also consumes quite some time,
656 * add that delay as well to get a better estimation
657 */
658 if (chan->flags & (IEEE80211_CHAN_NO_IR | IEEE80211_CHAN_RADAR))
659 return IEEE80211_PASSIVE_CHANNEL_TIME;
660 return IEEE80211_PROBE_DELAY + IEEE80211_CHANNEL_TIME;
661 }
662
663 static void ieee80211_scan_state_decision(struct ieee80211_local *local,
664 unsigned long *next_delay)
665 {
666 bool associated = false;
667 bool tx_empty = true;
668 bool bad_latency;
669 struct ieee80211_sub_if_data *sdata;
670 struct ieee80211_channel *next_chan;
671 enum mac80211_scan_state next_scan_state;
672 struct cfg80211_scan_request *scan_req;
673
674 /*
675 * check if at least one STA interface is associated,
676 * check if at least one STA interface has pending tx frames
677 * and grab the lowest used beacon interval
678 */
679 mutex_lock(&local->iflist_mtx);
680 list_for_each_entry(sdata, &local->interfaces, list) {
681 if (!ieee80211_sdata_running(sdata))
682 continue;
683
684 if (sdata->vif.type == NL80211_IFTYPE_STATION) {
685 if (sdata->u.mgd.associated) {
686 associated = true;
687
688 if (!qdisc_all_tx_empty(sdata->dev)) {
689 tx_empty = false;
690 break;
691 }
692 }
693 }
694 }
695 mutex_unlock(&local->iflist_mtx);
696
697 scan_req = rcu_dereference_protected(local->scan_req,
698 lockdep_is_held(&local->mtx));
699
700 next_chan = scan_req->channels[local->scan_channel_idx];
701
702 /*
703 * we're currently scanning a different channel, let's
704 * see if we can scan another channel without interfering
705 * with the current traffic situation.
706 *
707 * Keep good latency, do not stay off-channel more than 125 ms.
708 */
709
710 bad_latency = time_after(jiffies +
711 ieee80211_scan_get_channel_time(next_chan),
712 local->leave_oper_channel_time + HZ / 8);
713
714 if (associated && !tx_empty) {
715 if (scan_req->flags & NL80211_SCAN_FLAG_LOW_PRIORITY)
716 next_scan_state = SCAN_ABORT;
717 else
718 next_scan_state = SCAN_SUSPEND;
719 } else if (associated && bad_latency) {
720 next_scan_state = SCAN_SUSPEND;
721 } else {
722 next_scan_state = SCAN_SET_CHANNEL;
723 }
724
725 local->next_scan_state = next_scan_state;
726
727 *next_delay = 0;
728 }
729
730 static void ieee80211_scan_state_set_channel(struct ieee80211_local *local,
731 unsigned long *next_delay)
732 {
733 int skip;
734 struct ieee80211_channel *chan;
735 enum nl80211_bss_scan_width oper_scan_width;
736 struct cfg80211_scan_request *scan_req;
737
738 scan_req = rcu_dereference_protected(local->scan_req,
739 lockdep_is_held(&local->mtx));
740
741 skip = 0;
742 chan = scan_req->channels[local->scan_channel_idx];
743
744 local->scan_chandef.chan = chan;
745 local->scan_chandef.center_freq1 = chan->center_freq;
746 local->scan_chandef.center_freq2 = 0;
747 switch (scan_req->scan_width) {
748 case NL80211_BSS_CHAN_WIDTH_5:
749 local->scan_chandef.width = NL80211_CHAN_WIDTH_5;
750 break;
751 case NL80211_BSS_CHAN_WIDTH_10:
752 local->scan_chandef.width = NL80211_CHAN_WIDTH_10;
753 break;
754 case NL80211_BSS_CHAN_WIDTH_20:
755 /* If scanning on oper channel, use whatever channel-type
756 * is currently in use.
757 */
758 oper_scan_width = cfg80211_chandef_to_scan_width(
759 &local->_oper_chandef);
760 if (chan == local->_oper_chandef.chan &&
761 oper_scan_width == scan_req->scan_width)
762 local->scan_chandef = local->_oper_chandef;
763 else
764 local->scan_chandef.width = NL80211_CHAN_WIDTH_20_NOHT;
765 break;
766 }
767
768 if (ieee80211_hw_config(local, IEEE80211_CONF_CHANGE_CHANNEL))
769 skip = 1;
770
771 /* advance state machine to next channel/band */
772 local->scan_channel_idx++;
773
774 if (skip) {
775 /* if we skip this channel return to the decision state */
776 local->next_scan_state = SCAN_DECISION;
777 return;
778 }
779
780 /*
781 * Probe delay is used to update the NAV, cf. 11.1.3.2.2
782 * (which unfortunately doesn't say _why_ step a) is done,
783 * but it waits for the probe delay or until a frame is
784 * received - and the received frame would update the NAV).
785 * For now, we do not support waiting until a frame is
786 * received.
787 *
788 * In any case, it is not necessary for a passive scan.
789 */
790 if ((chan->flags & (IEEE80211_CHAN_NO_IR | IEEE80211_CHAN_RADAR)) ||
791 !scan_req->n_ssids) {
792 *next_delay = IEEE80211_PASSIVE_CHANNEL_TIME;
793 local->next_scan_state = SCAN_DECISION;
794 return;
795 }
796
797 /* active scan, send probes */
798 *next_delay = IEEE80211_PROBE_DELAY;
799 local->next_scan_state = SCAN_SEND_PROBE;
800 }
801
802 static void ieee80211_scan_state_suspend(struct ieee80211_local *local,
803 unsigned long *next_delay)
804 {
805 /* switch back to the operating channel */
806 local->scan_chandef.chan = NULL;
807 ieee80211_hw_config(local, IEEE80211_CONF_CHANGE_CHANNEL);
808
809 /* disable PS */
810 ieee80211_offchannel_return(local);
811
812 *next_delay = HZ / 5;
813 /* afterwards, resume scan & go to next channel */
814 local->next_scan_state = SCAN_RESUME;
815 }
816
817 static void ieee80211_scan_state_resume(struct ieee80211_local *local,
818 unsigned long *next_delay)
819 {
820 ieee80211_offchannel_stop_vifs(local);
821
822 if (local->ops->flush) {
823 ieee80211_flush_queues(local, NULL, false);
824 *next_delay = 0;
825 } else
826 *next_delay = HZ / 10;
827
828 /* remember when we left the operating channel */
829 local->leave_oper_channel_time = jiffies;
830
831 /* advance to the next channel to be scanned */
832 local->next_scan_state = SCAN_SET_CHANNEL;
833 }
834
835 void ieee80211_scan_work(struct work_struct *work)
836 {
837 struct ieee80211_local *local =
838 container_of(work, struct ieee80211_local, scan_work.work);
839 struct ieee80211_sub_if_data *sdata;
840 struct cfg80211_scan_request *scan_req;
841 unsigned long next_delay = 0;
842 bool aborted;
843
844 mutex_lock(&local->mtx);
845
846 if (!ieee80211_can_run_worker(local)) {
847 aborted = true;
848 goto out_complete;
849 }
850
851 sdata = rcu_dereference_protected(local->scan_sdata,
852 lockdep_is_held(&local->mtx));
853 scan_req = rcu_dereference_protected(local->scan_req,
854 lockdep_is_held(&local->mtx));
855
856 /* When scanning on-channel, the first-callback means completed. */
857 if (test_bit(SCAN_ONCHANNEL_SCANNING, &local->scanning)) {
858 aborted = test_and_clear_bit(SCAN_ABORTED, &local->scanning);
859 goto out_complete;
860 }
861
862 if (test_and_clear_bit(SCAN_COMPLETED, &local->scanning)) {
863 aborted = test_and_clear_bit(SCAN_ABORTED, &local->scanning);
864 goto out_complete;
865 }
866
867 if (!sdata || !scan_req)
868 goto out;
869
870 if (!local->scanning) {
871 int rc;
872
873 RCU_INIT_POINTER(local->scan_req, NULL);
874 RCU_INIT_POINTER(local->scan_sdata, NULL);
875
876 rc = __ieee80211_start_scan(sdata, scan_req);
877 if (rc) {
878 /* need to complete scan in cfg80211 */
879 rcu_assign_pointer(local->scan_req, scan_req);
880 aborted = true;
881 goto out_complete;
882 } else
883 goto out;
884 }
885
886 /*
887 * as long as no delay is required advance immediately
888 * without scheduling a new work
889 */
890 do {
891 if (!ieee80211_sdata_running(sdata)) {
892 aborted = true;
893 goto out_complete;
894 }
895
896 switch (local->next_scan_state) {
897 case SCAN_DECISION:
898 /* if no more bands/channels left, complete scan */
899 if (local->scan_channel_idx >= scan_req->n_channels) {
900 aborted = false;
901 goto out_complete;
902 }
903 ieee80211_scan_state_decision(local, &next_delay);
904 break;
905 case SCAN_SET_CHANNEL:
906 ieee80211_scan_state_set_channel(local, &next_delay);
907 break;
908 case SCAN_SEND_PROBE:
909 ieee80211_scan_state_send_probe(local, &next_delay);
910 break;
911 case SCAN_SUSPEND:
912 ieee80211_scan_state_suspend(local, &next_delay);
913 break;
914 case SCAN_RESUME:
915 ieee80211_scan_state_resume(local, &next_delay);
916 break;
917 case SCAN_ABORT:
918 aborted = true;
919 goto out_complete;
920 }
921 } while (next_delay == 0);
922
923 ieee80211_queue_delayed_work(&local->hw, &local->scan_work, next_delay);
924 goto out;
925
926 out_complete:
927 __ieee80211_scan_completed(&local->hw, aborted);
928 out:
929 mutex_unlock(&local->mtx);
930 }
931
932 int ieee80211_request_scan(struct ieee80211_sub_if_data *sdata,
933 struct cfg80211_scan_request *req)
934 {
935 int res;
936
937 mutex_lock(&sdata->local->mtx);
938 res = __ieee80211_start_scan(sdata, req);
939 mutex_unlock(&sdata->local->mtx);
940
941 return res;
942 }
943
944 int ieee80211_request_ibss_scan(struct ieee80211_sub_if_data *sdata,
945 const u8 *ssid, u8 ssid_len,
946 struct ieee80211_channel **channels,
947 unsigned int n_channels,
948 enum nl80211_bss_scan_width scan_width)
949 {
950 struct ieee80211_local *local = sdata->local;
951 int ret = -EBUSY, i, n_ch = 0;
952 enum ieee80211_band band;
953
954 mutex_lock(&local->mtx);
955
956 /* busy scanning */
957 if (local->scan_req)
958 goto unlock;
959
960 /* fill internal scan request */
961 if (!channels) {
962 int max_n;
963
964 for (band = 0; band < IEEE80211_NUM_BANDS; band++) {
965 if (!local->hw.wiphy->bands[band])
966 continue;
967
968 max_n = local->hw.wiphy->bands[band]->n_channels;
969 for (i = 0; i < max_n; i++) {
970 struct ieee80211_channel *tmp_ch =
971 &local->hw.wiphy->bands[band]->channels[i];
972
973 if (tmp_ch->flags & (IEEE80211_CHAN_NO_IR |
974 IEEE80211_CHAN_DISABLED))
975 continue;
976
977 local->int_scan_req->channels[n_ch] = tmp_ch;
978 n_ch++;
979 }
980 }
981
982 if (WARN_ON_ONCE(n_ch == 0))
983 goto unlock;
984
985 local->int_scan_req->n_channels = n_ch;
986 } else {
987 for (i = 0; i < n_channels; i++) {
988 if (channels[i]->flags & (IEEE80211_CHAN_NO_IR |
989 IEEE80211_CHAN_DISABLED))
990 continue;
991
992 local->int_scan_req->channels[n_ch] = channels[i];
993 n_ch++;
994 }
995
996 if (WARN_ON_ONCE(n_ch == 0))
997 goto unlock;
998
999 local->int_scan_req->n_channels = n_ch;
1000 }
1001
1002 local->int_scan_req->ssids = &local->scan_ssid;
1003 local->int_scan_req->n_ssids = 1;
1004 local->int_scan_req->scan_width = scan_width;
1005 memcpy(local->int_scan_req->ssids[0].ssid, ssid, IEEE80211_MAX_SSID_LEN);
1006 local->int_scan_req->ssids[0].ssid_len = ssid_len;
1007
1008 ret = __ieee80211_start_scan(sdata, sdata->local->int_scan_req);
1009 unlock:
1010 mutex_unlock(&local->mtx);
1011 return ret;
1012 }
1013
1014 /*
1015 * Only call this function when a scan can't be queued -- under RTNL.
1016 */
1017 void ieee80211_scan_cancel(struct ieee80211_local *local)
1018 {
1019 /*
1020 * We are canceling software scan, or deferred scan that was not
1021 * yet really started (see __ieee80211_start_scan ).
1022 *
1023 * Regarding hardware scan:
1024 * - we can not call __ieee80211_scan_completed() as when
1025 * SCAN_HW_SCANNING bit is set this function change
1026 * local->hw_scan_req to operate on 5G band, what race with
1027 * driver which can use local->hw_scan_req
1028 *
1029 * - we can not cancel scan_work since driver can schedule it
1030 * by ieee80211_scan_completed(..., true) to finish scan
1031 *
1032 * Hence we only call the cancel_hw_scan() callback, but the low-level
1033 * driver is still responsible for calling ieee80211_scan_completed()
1034 * after the scan was completed/aborted.
1035 */
1036
1037 mutex_lock(&local->mtx);
1038 if (!local->scan_req)
1039 goto out;
1040
1041 /*
1042 * We have a scan running and the driver already reported completion,
1043 * but the worker hasn't run yet or is stuck on the mutex - mark it as
1044 * cancelled.
1045 */
1046 if (test_bit(SCAN_HW_SCANNING, &local->scanning) &&
1047 test_bit(SCAN_COMPLETED, &local->scanning)) {
1048 set_bit(SCAN_HW_CANCELLED, &local->scanning);
1049 goto out;
1050 }
1051
1052 if (test_bit(SCAN_HW_SCANNING, &local->scanning)) {
1053 /*
1054 * Make sure that __ieee80211_scan_completed doesn't trigger a
1055 * scan on another band.
1056 */
1057 set_bit(SCAN_HW_CANCELLED, &local->scanning);
1058 if (local->ops->cancel_hw_scan)
1059 drv_cancel_hw_scan(local,
1060 rcu_dereference_protected(local->scan_sdata,
1061 lockdep_is_held(&local->mtx)));
1062 goto out;
1063 }
1064
1065 /*
1066 * If the work is currently running, it must be blocked on
1067 * the mutex, but we'll set scan_sdata = NULL and it'll
1068 * simply exit once it acquires the mutex.
1069 */
1070 cancel_delayed_work(&local->scan_work);
1071 /* and clean up */
1072 __ieee80211_scan_completed(&local->hw, true);
1073 out:
1074 mutex_unlock(&local->mtx);
1075 }
1076
1077 int __ieee80211_request_sched_scan_start(struct ieee80211_sub_if_data *sdata,
1078 struct cfg80211_sched_scan_request *req)
1079 {
1080 struct ieee80211_local *local = sdata->local;
1081 struct ieee80211_scan_ies sched_scan_ies = {};
1082 struct cfg80211_chan_def chandef;
1083 int ret, i, iebufsz, num_bands = 0;
1084 u32 rate_masks[IEEE80211_NUM_BANDS] = {};
1085 u8 bands_used = 0;
1086 u8 *ie;
1087 size_t len;
1088
1089 iebufsz = local->scan_ies_len + req->ie_len;
1090
1091 lockdep_assert_held(&local->mtx);
1092
1093 if (!local->ops->sched_scan_start)
1094 return -ENOTSUPP;
1095
1096 for (i = 0; i < IEEE80211_NUM_BANDS; i++) {
1097 if (local->hw.wiphy->bands[i]) {
1098 bands_used |= BIT(i);
1099 rate_masks[i] = (u32) -1;
1100 num_bands++;
1101 }
1102 }
1103
1104 ie = kzalloc(num_bands * iebufsz, GFP_KERNEL);
1105 if (!ie) {
1106 ret = -ENOMEM;
1107 goto out;
1108 }
1109
1110 ieee80211_prepare_scan_chandef(&chandef, req->scan_width);
1111
1112 len = ieee80211_build_preq_ies(local, ie, num_bands * iebufsz,
1113 &sched_scan_ies, req->ie,
1114 req->ie_len, bands_used,
1115 rate_masks, &chandef);
1116
1117 ret = drv_sched_scan_start(local, sdata, req, &sched_scan_ies);
1118 if (ret == 0) {
1119 rcu_assign_pointer(local->sched_scan_sdata, sdata);
1120 rcu_assign_pointer(local->sched_scan_req, req);
1121 }
1122
1123 kfree(ie);
1124
1125 out:
1126 if (ret) {
1127 /* Clean in case of failure after HW restart or upon resume. */
1128 RCU_INIT_POINTER(local->sched_scan_sdata, NULL);
1129 RCU_INIT_POINTER(local->sched_scan_req, NULL);
1130 }
1131
1132 return ret;
1133 }
1134
1135 int ieee80211_request_sched_scan_start(struct ieee80211_sub_if_data *sdata,
1136 struct cfg80211_sched_scan_request *req)
1137 {
1138 struct ieee80211_local *local = sdata->local;
1139 int ret;
1140
1141 mutex_lock(&local->mtx);
1142
1143 if (rcu_access_pointer(local->sched_scan_sdata)) {
1144 mutex_unlock(&local->mtx);
1145 return -EBUSY;
1146 }
1147
1148 ret = __ieee80211_request_sched_scan_start(sdata, req);
1149
1150 mutex_unlock(&local->mtx);
1151 return ret;
1152 }
1153
1154 int ieee80211_request_sched_scan_stop(struct ieee80211_local *local)
1155 {
1156 struct ieee80211_sub_if_data *sched_scan_sdata;
1157 int ret = -ENOENT;
1158
1159 mutex_lock(&local->mtx);
1160
1161 if (!local->ops->sched_scan_stop) {
1162 ret = -ENOTSUPP;
1163 goto out;
1164 }
1165
1166 /* We don't want to restart sched scan anymore. */
1167 RCU_INIT_POINTER(local->sched_scan_req, NULL);
1168
1169 sched_scan_sdata = rcu_dereference_protected(local->sched_scan_sdata,
1170 lockdep_is_held(&local->mtx));
1171 if (sched_scan_sdata) {
1172 ret = drv_sched_scan_stop(local, sched_scan_sdata);
1173 if (!ret)
1174 RCU_INIT_POINTER(local->sched_scan_sdata, NULL);
1175 }
1176 out:
1177 mutex_unlock(&local->mtx);
1178
1179 return ret;
1180 }
1181
1182 void ieee80211_sched_scan_results(struct ieee80211_hw *hw)
1183 {
1184 struct ieee80211_local *local = hw_to_local(hw);
1185
1186 trace_api_sched_scan_results(local);
1187
1188 cfg80211_sched_scan_results(hw->wiphy);
1189 }
1190 EXPORT_SYMBOL(ieee80211_sched_scan_results);
1191
1192 void ieee80211_sched_scan_end(struct ieee80211_local *local)
1193 {
1194 mutex_lock(&local->mtx);
1195
1196 if (!rcu_access_pointer(local->sched_scan_sdata)) {
1197 mutex_unlock(&local->mtx);
1198 return;
1199 }
1200
1201 RCU_INIT_POINTER(local->sched_scan_sdata, NULL);
1202
1203 /* If sched scan was aborted by the driver. */
1204 RCU_INIT_POINTER(local->sched_scan_req, NULL);
1205
1206 mutex_unlock(&local->mtx);
1207
1208 cfg80211_sched_scan_stopped(local->hw.wiphy);
1209 }
1210
1211 void ieee80211_sched_scan_stopped_work(struct work_struct *work)
1212 {
1213 struct ieee80211_local *local =
1214 container_of(work, struct ieee80211_local,
1215 sched_scan_stopped_work);
1216
1217 ieee80211_sched_scan_end(local);
1218 }
1219
1220 void ieee80211_sched_scan_stopped(struct ieee80211_hw *hw)
1221 {
1222 struct ieee80211_local *local = hw_to_local(hw);
1223
1224 trace_api_sched_scan_stopped(local);
1225
1226 /*
1227 * this shouldn't really happen, so for simplicity
1228 * simply ignore it, and let mac80211 reconfigure
1229 * the sched scan later on.
1230 */
1231 if (local->in_reconfig)
1232 return;
1233
1234 schedule_work(&local->sched_scan_stopped_work);
1235 }
1236 EXPORT_SYMBOL(ieee80211_sched_scan_stopped);
Linux kernel - Deliverables
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