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mac80211: rcu-ify scan and scheduled scan request pointers
[deliverable/linux.git] / net / mac80211 / scan.c
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CommitLineData
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 2013-2014 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 <linux/pm_qos.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
33void 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
42static 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
59struct ieee80211_bss *
60ieee80211_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 enum nl80211_bss_scan_width scan_width;
71 s32 signal = 0;
72
73 if (local->hw.flags & IEEE80211_HW_SIGNAL_DBM)
74 signal = rx_status->signal * 100;
75 else if (local->hw.flags & IEEE80211_HW_SIGNAL_UNSPEC)
76 signal = (rx_status->signal * 100) / local->hw.max_signal;
77
78 scan_width = NL80211_BSS_CHAN_WIDTH_20;
79 if (rx_status->flag & RX_FLAG_5MHZ)
80 scan_width = NL80211_BSS_CHAN_WIDTH_5;
81 if (rx_status->flag & RX_FLAG_10MHZ)
82 scan_width = NL80211_BSS_CHAN_WIDTH_10;
83
84 cbss = cfg80211_inform_bss_width_frame(local->hw.wiphy, channel,
85 scan_width, mgmt, len, signal,
86 GFP_ATOMIC);
87 if (!cbss)
88 return NULL;
89
90 bss = (void *)cbss->priv;
91
92 if (beacon)
93 bss->device_ts_beacon = rx_status->device_timestamp;
94 else
95 bss->device_ts_presp = rx_status->device_timestamp;
96
97 if (elems->parse_error) {
98 if (beacon)
99 bss->corrupt_data |= IEEE80211_BSS_CORRUPT_BEACON;
100 else
101 bss->corrupt_data |= IEEE80211_BSS_CORRUPT_PROBE_RESP;
102 } else {
103 if (beacon)
104 bss->corrupt_data &= ~IEEE80211_BSS_CORRUPT_BEACON;
105 else
106 bss->corrupt_data &= ~IEEE80211_BSS_CORRUPT_PROBE_RESP;
107 }
108
109 /* save the ERP value so that it is available at association time */
110 if (elems->erp_info && (!elems->parse_error ||
111 !(bss->valid_data & IEEE80211_BSS_VALID_ERP))) {
112 bss->erp_value = elems->erp_info[0];
113 bss->has_erp_value = true;
114 if (!elems->parse_error)
115 bss->valid_data |= IEEE80211_BSS_VALID_ERP;
116 }
117
118 /* replace old supported rates if we get new values */
119 if (!elems->parse_error ||
120 !(bss->valid_data & IEEE80211_BSS_VALID_RATES)) {
121 srlen = 0;
122 if (elems->supp_rates) {
123 clen = IEEE80211_MAX_SUPP_RATES;
124 if (clen > elems->supp_rates_len)
125 clen = elems->supp_rates_len;
126 memcpy(bss->supp_rates, elems->supp_rates, clen);
127 srlen += clen;
128 }
129 if (elems->ext_supp_rates) {
130 clen = IEEE80211_MAX_SUPP_RATES - srlen;
131 if (clen > elems->ext_supp_rates_len)
132 clen = elems->ext_supp_rates_len;
133 memcpy(bss->supp_rates + srlen, elems->ext_supp_rates,
134 clen);
135 srlen += clen;
136 }
137 if (srlen) {
138 bss->supp_rates_len = srlen;
139 if (!elems->parse_error)
140 bss->valid_data |= IEEE80211_BSS_VALID_RATES;
141 }
142 }
143
144 if (!elems->parse_error ||
145 !(bss->valid_data & IEEE80211_BSS_VALID_WMM)) {
146 bss->wmm_used = elems->wmm_param || elems->wmm_info;
147 bss->uapsd_supported = is_uapsd_supported(elems);
148 if (!elems->parse_error)
149 bss->valid_data |= IEEE80211_BSS_VALID_WMM;
150 }
151
152 if (beacon) {
153 struct ieee80211_supported_band *sband =
154 local->hw.wiphy->bands[rx_status->band];
155 if (!(rx_status->flag & RX_FLAG_HT) &&
156 !(rx_status->flag & RX_FLAG_VHT))
157 bss->beacon_rate =
158 &sband->bitrates[rx_status->rate_idx];
159 }
160
161 return bss;
162}
163
164void ieee80211_scan_rx(struct ieee80211_local *local, struct sk_buff *skb)
165{
166 struct ieee80211_rx_status *rx_status = IEEE80211_SKB_RXCB(skb);
167 struct ieee80211_sub_if_data *sdata1, *sdata2;
168 struct ieee80211_mgmt *mgmt = (void *)skb->data;
169 struct ieee80211_bss *bss;
170 u8 *elements;
171 struct ieee80211_channel *channel;
172 size_t baselen;
173 struct ieee802_11_elems elems;
174
175 if (skb->len < 24 ||
176 (!ieee80211_is_probe_resp(mgmt->frame_control) &&
177 !ieee80211_is_beacon(mgmt->frame_control)))
178 return;
179
180 sdata1 = rcu_dereference(local->scan_sdata);
181 sdata2 = rcu_dereference(local->sched_scan_sdata);
182
183 if (likely(!sdata1 && !sdata2))
184 return;
185
186 if (ieee80211_is_probe_resp(mgmt->frame_control)) {
187 /* ignore ProbeResp to foreign address */
188 if ((!sdata1 || !ether_addr_equal(mgmt->da, sdata1->vif.addr)) &&
189 (!sdata2 || !ether_addr_equal(mgmt->da, sdata2->vif.addr)))
190 return;
191
192 elements = mgmt->u.probe_resp.variable;
193 baselen = offsetof(struct ieee80211_mgmt, u.probe_resp.variable);
194 } else {
195 baselen = offsetof(struct ieee80211_mgmt, u.beacon.variable);
196 elements = mgmt->u.beacon.variable;
197 }
198
199 if (baselen > skb->len)
200 return;
201
202 ieee802_11_parse_elems(elements, skb->len - baselen, false, &elems);
203
204 channel = ieee80211_get_channel(local->hw.wiphy, rx_status->freq);
205
206 if (!channel || channel->flags & IEEE80211_CHAN_DISABLED)
207 return;
208
209 bss = ieee80211_bss_info_update(local, rx_status,
210 mgmt, skb->len, &elems,
211 channel);
212 if (bss)
213 ieee80211_rx_bss_put(local, bss);
214}
215
216static void
217ieee80211_prepare_scan_chandef(struct cfg80211_chan_def *chandef,
218 enum nl80211_bss_scan_width scan_width)
219{
220 memset(chandef, 0, sizeof(*chandef));
221 switch (scan_width) {
222 case NL80211_BSS_CHAN_WIDTH_5:
223 chandef->width = NL80211_CHAN_WIDTH_5;
224 break;
225 case NL80211_BSS_CHAN_WIDTH_10:
226 chandef->width = NL80211_CHAN_WIDTH_10;
227 break;
228 default:
229 chandef->width = NL80211_CHAN_WIDTH_20_NOHT;
230 break;
231 }
232}
233
234/* return false if no more work */
235static bool ieee80211_prep_hw_scan(struct ieee80211_local *local)
236{
237 struct cfg80211_scan_request *req;
238 struct cfg80211_chan_def chandef;
239 u8 bands_used = 0;
240 int i, ielen, n_chans;
241
242 req = rcu_dereference_protected(local->scan_req,
243 lockdep_is_held(&local->mtx));
244
245 if (test_bit(SCAN_HW_CANCELLED, &local->scanning))
246 return false;
247
248 if (local->hw.flags & IEEE80211_SINGLE_HW_SCAN_ON_ALL_BANDS) {
249 for (i = 0; i < req->n_channels; i++) {
250 local->hw_scan_req->req.channels[i] = req->channels[i];
251 bands_used |= BIT(req->channels[i]->band);
252 }
253
254 n_chans = req->n_channels;
255 } else {
256 do {
257 if (local->hw_scan_band == IEEE80211_NUM_BANDS)
258 return false;
259
260 n_chans = 0;
261
262 for (i = 0; i < req->n_channels; i++) {
263 if (req->channels[i]->band !=
264 local->hw_scan_band)
265 continue;
266 local->hw_scan_req->req.channels[n_chans] =
267 req->channels[i];
268 n_chans++;
269 bands_used |= BIT(req->channels[i]->band);
270 }
271
272 local->hw_scan_band++;
273 } while (!n_chans);
274 }
275
276 local->hw_scan_req->req.n_channels = n_chans;
277 ieee80211_prepare_scan_chandef(&chandef, req->scan_width);
278
279 ielen = ieee80211_build_preq_ies(local,
280 (u8 *)local->hw_scan_req->req.ie,
281 local->hw_scan_ies_bufsize,
282 &local->hw_scan_req->ies,
283 req->ie, req->ie_len,
284 bands_used, req->rates, &chandef);
285 local->hw_scan_req->req.ie_len = ielen;
286 local->hw_scan_req->req.no_cck = req->no_cck;
287
288 return true;
289}
290
291static void __ieee80211_scan_completed(struct ieee80211_hw *hw, bool aborted)
292{
293 struct ieee80211_local *local = hw_to_local(hw);
294 bool hw_scan = local->ops->hw_scan;
295 bool was_scanning = local->scanning;
296 struct cfg80211_scan_request *scan_req;
297
298 lockdep_assert_held(&local->mtx);
299
300 /*
301 * It's ok to abort a not-yet-running scan (that
302 * we have one at all will be verified by checking
303 * local->scan_req next), but not to complete it
304 * successfully.
305 */
306 if (WARN_ON(!local->scanning && !aborted))
307 aborted = true;
308
309 if (WARN_ON(!local->scan_req))
310 return;
311
312 if (hw_scan && !aborted &&
313 !(local->hw.flags & IEEE80211_SINGLE_HW_SCAN_ON_ALL_BANDS) &&
314 ieee80211_prep_hw_scan(local)) {
315 int rc;
316
317 rc = drv_hw_scan(local,
318 rcu_dereference_protected(local->scan_sdata,
319 lockdep_is_held(&local->mtx)),
320 local->hw_scan_req);
321
322 if (rc == 0)
323 return;
324 }
325
326 kfree(local->hw_scan_req);
327 local->hw_scan_req = NULL;
328
329 scan_req = rcu_dereference_protected(local->scan_req,
330 lockdep_is_held(&local->mtx));
331
332 if (scan_req != local->int_scan_req)
333 cfg80211_scan_done(scan_req, aborted);
334 RCU_INIT_POINTER(local->scan_req, NULL);
335 RCU_INIT_POINTER(local->scan_sdata, NULL);
336
337 local->scanning = 0;
338 local->scan_chandef.chan = NULL;
339
340 /* Set power back to normal operating levels. */
341 ieee80211_hw_config(local, 0);
342
343 if (!hw_scan) {
344 ieee80211_configure_filter(local);
345 drv_sw_scan_complete(local);
346 ieee80211_offchannel_return(local);
347 }
348
349 ieee80211_recalc_idle(local);
350
351 ieee80211_mlme_notify_scan_completed(local);
352 ieee80211_ibss_notify_scan_completed(local);
353 ieee80211_mesh_notify_scan_completed(local);
354 if (was_scanning)
355 ieee80211_start_next_roc(local);
356}
357
358void ieee80211_scan_completed(struct ieee80211_hw *hw, bool aborted)
359{
360 struct ieee80211_local *local = hw_to_local(hw);
361
362 trace_api_scan_completed(local, aborted);
363
364 set_bit(SCAN_COMPLETED, &local->scanning);
365 if (aborted)
366 set_bit(SCAN_ABORTED, &local->scanning);
367 ieee80211_queue_delayed_work(&local->hw, &local->scan_work, 0);
368}
369EXPORT_SYMBOL(ieee80211_scan_completed);
370
371static int ieee80211_start_sw_scan(struct ieee80211_local *local)
372{
373 /* Software scan is not supported in multi-channel cases */
374 if (local->use_chanctx)
375 return -EOPNOTSUPP;
376
377 /*
378 * Hardware/driver doesn't support hw_scan, so use software
379 * scanning instead. First send a nullfunc frame with power save
380 * bit on so that AP will buffer the frames for us while we are not
381 * listening, then send probe requests to each channel and wait for
382 * the responses. After all channels are scanned, tune back to the
383 * original channel and send a nullfunc frame with power save bit
384 * off to trigger the AP to send us all the buffered frames.
385 *
386 * Note that while local->sw_scanning is true everything else but
387 * nullfunc frames and probe requests will be dropped in
388 * ieee80211_tx_h_check_assoc().
389 */
390 drv_sw_scan_start(local);
391
392 local->leave_oper_channel_time = jiffies;
393 local->next_scan_state = SCAN_DECISION;
394 local->scan_channel_idx = 0;
395
396 ieee80211_offchannel_stop_vifs(local);
397
398 /* ensure nullfunc is transmitted before leaving operating channel */
399 ieee80211_flush_queues(local, NULL);
400
401 ieee80211_configure_filter(local);
402
403 /* We need to set power level at maximum rate for scanning. */
404 ieee80211_hw_config(local, 0);
405
406 ieee80211_queue_delayed_work(&local->hw,
407 &local->scan_work, 0);
408
409 return 0;
410}
411
412static bool ieee80211_can_scan(struct ieee80211_local *local,
413 struct ieee80211_sub_if_data *sdata)
414{
415 if (local->radar_detect_enabled)
416 return false;
417
418 if (!list_empty(&local->roc_list))
419 return false;
420
421 if (sdata->vif.type == NL80211_IFTYPE_STATION &&
422 sdata->u.mgd.flags & IEEE80211_STA_CONNECTION_POLL)
423 return false;
424
425 return true;
426}
427
428void ieee80211_run_deferred_scan(struct ieee80211_local *local)
429{
430 lockdep_assert_held(&local->mtx);
431
432 if (!local->scan_req || local->scanning)
433 return;
434
435 if (!ieee80211_can_scan(local,
436 rcu_dereference_protected(
437 local->scan_sdata,
438 lockdep_is_held(&local->mtx))))
439 return;
440
441 ieee80211_queue_delayed_work(&local->hw, &local->scan_work,
442 round_jiffies_relative(0));
443}
444
445static void ieee80211_scan_state_send_probe(struct ieee80211_local *local,
446 unsigned long *next_delay)
447{
448 int i;
449 struct ieee80211_sub_if_data *sdata;
450 struct cfg80211_scan_request *scan_req;
451 enum ieee80211_band band = local->hw.conf.chandef.chan->band;
452 u32 tx_flags;
453
454 scan_req = rcu_dereference_protected(local->scan_req,
455 lockdep_is_held(&local->mtx));
456
457 tx_flags = IEEE80211_TX_INTFL_OFFCHAN_TX_OK;
458 if (scan_req->no_cck)
459 tx_flags |= IEEE80211_TX_CTL_NO_CCK_RATE;
460
461 sdata = rcu_dereference_protected(local->scan_sdata,
462 lockdep_is_held(&local->mtx));
463
464 for (i = 0; i < scan_req->n_ssids; i++)
465 ieee80211_send_probe_req(
466 sdata, NULL,
467 scan_req->ssids[i].ssid, scan_req->ssids[i].ssid_len,
468 scan_req->ie, scan_req->ie_len,
469 scan_req->rates[band], false,
470 tx_flags, local->hw.conf.chandef.chan, true);
471
472 /*
473 * After sending probe requests, wait for probe responses
474 * on the channel.
475 */
476 *next_delay = IEEE80211_CHANNEL_TIME;
477 local->next_scan_state = SCAN_DECISION;
478}
479
480static int __ieee80211_start_scan(struct ieee80211_sub_if_data *sdata,
481 struct cfg80211_scan_request *req)
482{
483 struct ieee80211_local *local = sdata->local;
484 int rc;
485
486 lockdep_assert_held(&local->mtx);
487
488 if (local->scan_req)
489 return -EBUSY;
490
491 if (!ieee80211_can_scan(local, sdata)) {
492 /* wait for the work to finish/time out */
493 rcu_assign_pointer(local->scan_req, req);
494 rcu_assign_pointer(local->scan_sdata, sdata);
495 return 0;
496 }
497
498 if (local->ops->hw_scan) {
499 u8 *ies;
500
501 local->hw_scan_ies_bufsize = local->scan_ies_len + req->ie_len;
502
503 if (local->hw.flags & IEEE80211_SINGLE_HW_SCAN_ON_ALL_BANDS) {
504 int i, n_bands = 0;
505 u8 bands_counted = 0;
506
507 for (i = 0; i < req->n_channels; i++) {
508 if (bands_counted & BIT(req->channels[i]->band))
509 continue;
510 bands_counted |= BIT(req->channels[i]->band);
511 n_bands++;
512 }
513
514 local->hw_scan_ies_bufsize *= n_bands;
515 }
516
517 local->hw_scan_req = kmalloc(
518 sizeof(*local->hw_scan_req) +
519 req->n_channels * sizeof(req->channels[0]) +
520 local->hw_scan_ies_bufsize, GFP_KERNEL);
521 if (!local->hw_scan_req)
522 return -ENOMEM;
523
524 local->hw_scan_req->req.ssids = req->ssids;
525 local->hw_scan_req->req.n_ssids = req->n_ssids;
526 ies = (u8 *)local->hw_scan_req +
527 sizeof(*local->hw_scan_req) +
528 req->n_channels * sizeof(req->channels[0]);
529 local->hw_scan_req->req.ie = ies;
530 local->hw_scan_req->req.flags = req->flags;
531
532 local->hw_scan_band = 0;
533
534 /*
535 * After allocating local->hw_scan_req, we must
536 * go through until ieee80211_prep_hw_scan(), so
537 * anything that might be changed here and leave
538 * this function early must not go after this
539 * allocation.
540 */
541 }
542
543 rcu_assign_pointer(local->scan_req, req);
544 rcu_assign_pointer(local->scan_sdata, sdata);
545
546 if (local->ops->hw_scan) {
547 __set_bit(SCAN_HW_SCANNING, &local->scanning);
548 } else if ((req->n_channels == 1) &&
549 (req->channels[0] == local->_oper_chandef.chan)) {
550 /*
551 * If we are scanning only on the operating channel
552 * then we do not need to stop normal activities
553 */
554 unsigned long next_delay;
555
556 __set_bit(SCAN_ONCHANNEL_SCANNING, &local->scanning);
557
558 ieee80211_recalc_idle(local);
559
560 /* Notify driver scan is starting, keep order of operations
561 * same as normal software scan, in case that matters. */
562 drv_sw_scan_start(local);
563
564 ieee80211_configure_filter(local); /* accept probe-responses */
565
566 /* We need to ensure power level is at max for scanning. */
567 ieee80211_hw_config(local, 0);
568
569 if ((req->channels[0]->flags &
570 IEEE80211_CHAN_NO_IR) ||
571 !req->n_ssids) {
572 next_delay = IEEE80211_PASSIVE_CHANNEL_TIME;
573 } else {
574 ieee80211_scan_state_send_probe(local, &next_delay);
575 next_delay = IEEE80211_CHANNEL_TIME;
576 }
577
578 /* Now, just wait a bit and we are all done! */
579 ieee80211_queue_delayed_work(&local->hw, &local->scan_work,
580 next_delay);
581 return 0;
582 } else {
583 /* Do normal software scan */
584 __set_bit(SCAN_SW_SCANNING, &local->scanning);
585 }
586
587 ieee80211_recalc_idle(local);
588
589 if (local->ops->hw_scan) {
590 WARN_ON(!ieee80211_prep_hw_scan(local));
591 rc = drv_hw_scan(local, sdata, local->hw_scan_req);
592 } else
593 rc = ieee80211_start_sw_scan(local);
594
595 if (rc) {
596 kfree(local->hw_scan_req);
597 local->hw_scan_req = NULL;
598 local->scanning = 0;
599
600 ieee80211_recalc_idle(local);
601
602 local->scan_req = NULL;
603 RCU_INIT_POINTER(local->scan_sdata, NULL);
604 }
605
606 return rc;
607}
608
609static unsigned long
610ieee80211_scan_get_channel_time(struct ieee80211_channel *chan)
611{
612 /*
613 * TODO: channel switching also consumes quite some time,
614 * add that delay as well to get a better estimation
615 */
616 if (chan->flags & IEEE80211_CHAN_NO_IR)
617 return IEEE80211_PASSIVE_CHANNEL_TIME;
618 return IEEE80211_PROBE_DELAY + IEEE80211_CHANNEL_TIME;
619}
620
621static void ieee80211_scan_state_decision(struct ieee80211_local *local,
622 unsigned long *next_delay)
623{
624 bool associated = false;
625 bool tx_empty = true;
626 bool bad_latency;
627 struct ieee80211_sub_if_data *sdata;
628 struct ieee80211_channel *next_chan;
629 enum mac80211_scan_state next_scan_state;
630 struct cfg80211_scan_request *scan_req;
631
632 /*
633 * check if at least one STA interface is associated,
634 * check if at least one STA interface has pending tx frames
635 * and grab the lowest used beacon interval
636 */
637 mutex_lock(&local->iflist_mtx);
638 list_for_each_entry(sdata, &local->interfaces, list) {
639 if (!ieee80211_sdata_running(sdata))
640 continue;
641
642 if (sdata->vif.type == NL80211_IFTYPE_STATION) {
643 if (sdata->u.mgd.associated) {
644 associated = true;
645
646 if (!qdisc_all_tx_empty(sdata->dev)) {
647 tx_empty = false;
648 break;
649 }
650 }
651 }
652 }
653 mutex_unlock(&local->iflist_mtx);
654
655 scan_req = rcu_dereference_protected(local->scan_req,
656 lockdep_is_held(&local->mtx));
657
658 next_chan = scan_req->channels[local->scan_channel_idx];
659
660 /*
661 * we're currently scanning a different channel, let's
662 * see if we can scan another channel without interfering
663 * with the current traffic situation.
664 *
665 * Keep good latency, do not stay off-channel more than 125 ms.
666 */
667
668 bad_latency = time_after(jiffies +
669 ieee80211_scan_get_channel_time(next_chan),
670 local->leave_oper_channel_time + HZ / 8);
671
672 if (associated && !tx_empty) {
673 if (scan_req->flags & NL80211_SCAN_FLAG_LOW_PRIORITY)
674 next_scan_state = SCAN_ABORT;
675 else
676 next_scan_state = SCAN_SUSPEND;
677 } else if (associated && bad_latency) {
678 next_scan_state = SCAN_SUSPEND;
679 } else {
680 next_scan_state = SCAN_SET_CHANNEL;
681 }
682
683 local->next_scan_state = next_scan_state;
684
685 *next_delay = 0;
686}
687
688static void ieee80211_scan_state_set_channel(struct ieee80211_local *local,
689 unsigned long *next_delay)
690{
691 int skip;
692 struct ieee80211_channel *chan;
693 enum nl80211_bss_scan_width oper_scan_width;
694 struct cfg80211_scan_request *scan_req;
695
696 scan_req = rcu_dereference_protected(local->scan_req,
697 lockdep_is_held(&local->mtx));
698
699 skip = 0;
700 chan = scan_req->channels[local->scan_channel_idx];
701
702 local->scan_chandef.chan = chan;
703 local->scan_chandef.center_freq1 = chan->center_freq;
704 local->scan_chandef.center_freq2 = 0;
705 switch (scan_req->scan_width) {
706 case NL80211_BSS_CHAN_WIDTH_5:
707 local->scan_chandef.width = NL80211_CHAN_WIDTH_5;
708 break;
709 case NL80211_BSS_CHAN_WIDTH_10:
710 local->scan_chandef.width = NL80211_CHAN_WIDTH_10;
711 break;
712 case NL80211_BSS_CHAN_WIDTH_20:
713 /* If scanning on oper channel, use whatever channel-type
714 * is currently in use.
715 */
716 oper_scan_width = cfg80211_chandef_to_scan_width(
717 &local->_oper_chandef);
718 if (chan == local->_oper_chandef.chan &&
719 oper_scan_width == scan_req->scan_width)
720 local->scan_chandef = local->_oper_chandef;
721 else
722 local->scan_chandef.width = NL80211_CHAN_WIDTH_20_NOHT;
723 break;
724 }
725
726 if (ieee80211_hw_config(local, IEEE80211_CONF_CHANGE_CHANNEL))
727 skip = 1;
728
729 /* advance state machine to next channel/band */
730 local->scan_channel_idx++;
731
732 if (skip) {
733 /* if we skip this channel return to the decision state */
734 local->next_scan_state = SCAN_DECISION;
735 return;
736 }
737
738 /*
739 * Probe delay is used to update the NAV, cf. 11.1.3.2.2
740 * (which unfortunately doesn't say _why_ step a) is done,
741 * but it waits for the probe delay or until a frame is
742 * received - and the received frame would update the NAV).
743 * For now, we do not support waiting until a frame is
744 * received.
745 *
746 * In any case, it is not necessary for a passive scan.
747 */
748 if (chan->flags & IEEE80211_CHAN_NO_IR || !scan_req->n_ssids) {
749 *next_delay = IEEE80211_PASSIVE_CHANNEL_TIME;
750 local->next_scan_state = SCAN_DECISION;
751 return;
752 }
753
754 /* active scan, send probes */
755 *next_delay = IEEE80211_PROBE_DELAY;
756 local->next_scan_state = SCAN_SEND_PROBE;
757}
758
759static void ieee80211_scan_state_suspend(struct ieee80211_local *local,
760 unsigned long *next_delay)
761{
762 /* switch back to the operating channel */
763 local->scan_chandef.chan = NULL;
764 ieee80211_hw_config(local, IEEE80211_CONF_CHANGE_CHANNEL);
765
766 /* disable PS */
767 ieee80211_offchannel_return(local);
768
769 *next_delay = HZ / 5;
770 /* afterwards, resume scan & go to next channel */
771 local->next_scan_state = SCAN_RESUME;
772}
773
774static void ieee80211_scan_state_resume(struct ieee80211_local *local,
775 unsigned long *next_delay)
776{
777 ieee80211_offchannel_stop_vifs(local);
778
779 if (local->ops->flush) {
780 ieee80211_flush_queues(local, NULL);
781 *next_delay = 0;
782 } else
783 *next_delay = HZ / 10;
784
785 /* remember when we left the operating channel */
786 local->leave_oper_channel_time = jiffies;
787
788 /* advance to the next channel to be scanned */
789 local->next_scan_state = SCAN_SET_CHANNEL;
790}
791
792void ieee80211_scan_work(struct work_struct *work)
793{
794 struct ieee80211_local *local =
795 container_of(work, struct ieee80211_local, scan_work.work);
796 struct ieee80211_sub_if_data *sdata;
797 struct cfg80211_scan_request *scan_req;
798 unsigned long next_delay = 0;
799 bool aborted;
800
801 mutex_lock(&local->mtx);
802
803 sdata = rcu_dereference_protected(local->scan_sdata,
804 lockdep_is_held(&local->mtx));
805 scan_req = rcu_dereference_protected(local->scan_req,
806 lockdep_is_held(&local->mtx));
807
808 /* When scanning on-channel, the first-callback means completed. */
809 if (test_bit(SCAN_ONCHANNEL_SCANNING, &local->scanning)) {
810 aborted = test_and_clear_bit(SCAN_ABORTED, &local->scanning);
811 goto out_complete;
812 }
813
814 if (test_and_clear_bit(SCAN_COMPLETED, &local->scanning)) {
815 aborted = test_and_clear_bit(SCAN_ABORTED, &local->scanning);
816 goto out_complete;
817 }
818
819 if (!sdata || !scan_req)
820 goto out;
821
822 if (!local->scanning) {
823 int rc;
824
825 RCU_INIT_POINTER(local->scan_req, NULL);
826 RCU_INIT_POINTER(local->scan_sdata, NULL);
827
828 rc = __ieee80211_start_scan(sdata, scan_req);
829 if (rc) {
830 /* need to complete scan in cfg80211 */
831 rcu_assign_pointer(local->scan_req, scan_req);
832 aborted = true;
833 goto out_complete;
834 } else
835 goto out;
836 }
837
838 /*
839 * as long as no delay is required advance immediately
840 * without scheduling a new work
841 */
842 do {
843 if (!ieee80211_sdata_running(sdata)) {
844 aborted = true;
845 goto out_complete;
846 }
847
848 switch (local->next_scan_state) {
849 case SCAN_DECISION:
850 /* if no more bands/channels left, complete scan */
851 if (local->scan_channel_idx >= scan_req->n_channels) {
852 aborted = false;
853 goto out_complete;
854 }
855 ieee80211_scan_state_decision(local, &next_delay);
856 break;
857 case SCAN_SET_CHANNEL:
858 ieee80211_scan_state_set_channel(local, &next_delay);
859 break;
860 case SCAN_SEND_PROBE:
861 ieee80211_scan_state_send_probe(local, &next_delay);
862 break;
863 case SCAN_SUSPEND:
864 ieee80211_scan_state_suspend(local, &next_delay);
865 break;
866 case SCAN_RESUME:
867 ieee80211_scan_state_resume(local, &next_delay);
868 break;
869 case SCAN_ABORT:
870 aborted = true;
871 goto out_complete;
872 }
873 } while (next_delay == 0);
874
875 ieee80211_queue_delayed_work(&local->hw, &local->scan_work, next_delay);
876 goto out;
877
878out_complete:
879 __ieee80211_scan_completed(&local->hw, aborted);
880out:
881 mutex_unlock(&local->mtx);
882}
883
884int ieee80211_request_scan(struct ieee80211_sub_if_data *sdata,
885 struct cfg80211_scan_request *req)
886{
887 int res;
888
889 mutex_lock(&sdata->local->mtx);
890 res = __ieee80211_start_scan(sdata, req);
891 mutex_unlock(&sdata->local->mtx);
892
893 return res;
894}
895
896int ieee80211_request_ibss_scan(struct ieee80211_sub_if_data *sdata,
897 const u8 *ssid, u8 ssid_len,
898 struct ieee80211_channel *chan,
899 enum nl80211_bss_scan_width scan_width)
900{
901 struct ieee80211_local *local = sdata->local;
902 int ret = -EBUSY;
903 enum ieee80211_band band;
904
905 mutex_lock(&local->mtx);
906
907 /* busy scanning */
908 if (local->scan_req)
909 goto unlock;
910
911 /* fill internal scan request */
912 if (!chan) {
913 int i, max_n;
914 int n_ch = 0;
915
916 for (band = 0; band < IEEE80211_NUM_BANDS; band++) {
917 if (!local->hw.wiphy->bands[band])
918 continue;
919
920 max_n = local->hw.wiphy->bands[band]->n_channels;
921 for (i = 0; i < max_n; i++) {
922 struct ieee80211_channel *tmp_ch =
923 &local->hw.wiphy->bands[band]->channels[i];
924
925 if (tmp_ch->flags & (IEEE80211_CHAN_NO_IR |
926 IEEE80211_CHAN_DISABLED))
927 continue;
928
929 local->int_scan_req->channels[n_ch] = tmp_ch;
930 n_ch++;
931 }
932 }
933
934 if (WARN_ON_ONCE(n_ch == 0))
935 goto unlock;
936
937 local->int_scan_req->n_channels = n_ch;
938 } else {
939 if (WARN_ON_ONCE(chan->flags & (IEEE80211_CHAN_NO_IR |
940 IEEE80211_CHAN_DISABLED)))
941 goto unlock;
942
943 local->int_scan_req->channels[0] = chan;
944 local->int_scan_req->n_channels = 1;
945 }
946
947 local->int_scan_req->ssids = &local->scan_ssid;
948 local->int_scan_req->n_ssids = 1;
949 local->int_scan_req->scan_width = scan_width;
950 memcpy(local->int_scan_req->ssids[0].ssid, ssid, IEEE80211_MAX_SSID_LEN);
951 local->int_scan_req->ssids[0].ssid_len = ssid_len;
952
953 ret = __ieee80211_start_scan(sdata, sdata->local->int_scan_req);
954 unlock:
955 mutex_unlock(&local->mtx);
956 return ret;
957}
958
959/*
960 * Only call this function when a scan can't be queued -- under RTNL.
961 */
962void ieee80211_scan_cancel(struct ieee80211_local *local)
963{
964 /*
965 * We are canceling software scan, or deferred scan that was not
966 * yet really started (see __ieee80211_start_scan ).
967 *
968 * Regarding hardware scan:
969 * - we can not call __ieee80211_scan_completed() as when
970 * SCAN_HW_SCANNING bit is set this function change
971 * local->hw_scan_req to operate on 5G band, what race with
972 * driver which can use local->hw_scan_req
973 *
974 * - we can not cancel scan_work since driver can schedule it
975 * by ieee80211_scan_completed(..., true) to finish scan
976 *
977 * Hence we only call the cancel_hw_scan() callback, but the low-level
978 * driver is still responsible for calling ieee80211_scan_completed()
979 * after the scan was completed/aborted.
980 */
981
982 mutex_lock(&local->mtx);
983 if (!local->scan_req)
984 goto out;
985
986 /*
987 * We have a scan running and the driver already reported completion,
988 * but the worker hasn't run yet or is stuck on the mutex - mark it as
989 * cancelled.
990 */
991 if (test_bit(SCAN_HW_SCANNING, &local->scanning) &&
992 test_bit(SCAN_COMPLETED, &local->scanning)) {
993 set_bit(SCAN_HW_CANCELLED, &local->scanning);
994 goto out;
995 }
996
997 if (test_bit(SCAN_HW_SCANNING, &local->scanning)) {
998 /*
999 * Make sure that __ieee80211_scan_completed doesn't trigger a
1000 * scan on another band.
1001 */
1002 set_bit(SCAN_HW_CANCELLED, &local->scanning);
1003 if (local->ops->cancel_hw_scan)
1004 drv_cancel_hw_scan(local,
1005 rcu_dereference_protected(local->scan_sdata,
1006 lockdep_is_held(&local->mtx)));
1007 goto out;
1008 }
1009
1010 /*
1011 * If the work is currently running, it must be blocked on
1012 * the mutex, but we'll set scan_sdata = NULL and it'll
1013 * simply exit once it acquires the mutex.
1014 */
1015 cancel_delayed_work(&local->scan_work);
1016 /* and clean up */
1017 __ieee80211_scan_completed(&local->hw, true);
1018out:
1019 mutex_unlock(&local->mtx);
1020}
1021
1022int __ieee80211_request_sched_scan_start(struct ieee80211_sub_if_data *sdata,
1023 struct cfg80211_sched_scan_request *req)
1024{
1025 struct ieee80211_local *local = sdata->local;
1026 struct ieee80211_scan_ies sched_scan_ies = {};
1027 struct cfg80211_chan_def chandef;
1028 int ret, i, iebufsz, num_bands = 0;
1029 u32 rate_masks[IEEE80211_NUM_BANDS] = {};
1030 u8 bands_used = 0;
1031 u8 *ie;
1032 size_t len;
1033
1034 iebufsz = local->scan_ies_len + req->ie_len;
1035
1036 lockdep_assert_held(&local->mtx);
1037
1038 if (!local->ops->sched_scan_start)
1039 return -ENOTSUPP;
1040
1041 for (i = 0; i < IEEE80211_NUM_BANDS; i++) {
1042 if (local->hw.wiphy->bands[i]) {
1043 bands_used |= BIT(i);
1044 rate_masks[i] = (u32) -1;
1045 num_bands++;
1046 }
1047 }
1048
1049 ie = kzalloc(num_bands * iebufsz, GFP_KERNEL);
1050 if (!ie) {
1051 ret = -ENOMEM;
1052 goto out;
1053 }
1054
1055 ieee80211_prepare_scan_chandef(&chandef, req->scan_width);
1056
1057 len = ieee80211_build_preq_ies(local, ie, num_bands * iebufsz,
1058 &sched_scan_ies, req->ie,
1059 req->ie_len, bands_used,
1060 rate_masks, &chandef);
1061
1062 ret = drv_sched_scan_start(local, sdata, req, &sched_scan_ies);
1063 if (ret == 0) {
1064 rcu_assign_pointer(local->sched_scan_sdata, sdata);
1065 rcu_assign_pointer(local->sched_scan_req, req);
1066 }
1067
1068 kfree(ie);
1069
1070out:
1071 if (ret) {
1072 /* Clean in case of failure after HW restart or upon resume. */
1073 RCU_INIT_POINTER(local->sched_scan_sdata, NULL);
1074 RCU_INIT_POINTER(local->sched_scan_req, NULL);
1075 }
1076
1077 return ret;
1078}
1079
1080int ieee80211_request_sched_scan_start(struct ieee80211_sub_if_data *sdata,
1081 struct cfg80211_sched_scan_request *req)
1082{
1083 struct ieee80211_local *local = sdata->local;
1084 int ret;
1085
1086 mutex_lock(&local->mtx);
1087
1088 if (rcu_access_pointer(local->sched_scan_sdata)) {
1089 mutex_unlock(&local->mtx);
1090 return -EBUSY;
1091 }
1092
1093 ret = __ieee80211_request_sched_scan_start(sdata, req);
1094
1095 mutex_unlock(&local->mtx);
1096 return ret;
1097}
1098
1099int ieee80211_request_sched_scan_stop(struct ieee80211_sub_if_data *sdata)
1100{
1101 struct ieee80211_local *local = sdata->local;
1102 int ret = 0;
1103
1104 mutex_lock(&local->mtx);
1105
1106 if (!local->ops->sched_scan_stop) {
1107 ret = -ENOTSUPP;
1108 goto out;
1109 }
1110
1111 /* We don't want to restart sched scan anymore. */
1112 RCU_INIT_POINTER(local->sched_scan_req, NULL);
1113
1114 if (rcu_access_pointer(local->sched_scan_sdata)) {
1115 ret = drv_sched_scan_stop(local, sdata);
1116 if (!ret)
1117 RCU_INIT_POINTER(local->sched_scan_sdata, NULL);
1118 }
1119out:
1120 mutex_unlock(&local->mtx);
1121
1122 return ret;
1123}
1124
1125void ieee80211_sched_scan_results(struct ieee80211_hw *hw)
1126{
1127 struct ieee80211_local *local = hw_to_local(hw);
1128
1129 trace_api_sched_scan_results(local);
1130
1131 cfg80211_sched_scan_results(hw->wiphy);
1132}
1133EXPORT_SYMBOL(ieee80211_sched_scan_results);
1134
1135void ieee80211_sched_scan_end(struct ieee80211_local *local)
1136{
1137 mutex_lock(&local->mtx);
1138
1139 if (!rcu_access_pointer(local->sched_scan_sdata)) {
1140 mutex_unlock(&local->mtx);
1141 return;
1142 }
1143
1144 RCU_INIT_POINTER(local->sched_scan_sdata, NULL);
1145
1146 /* If sched scan was aborted by the driver. */
1147 RCU_INIT_POINTER(local->sched_scan_req, NULL);
1148
1149 mutex_unlock(&local->mtx);
1150
1151 cfg80211_sched_scan_stopped(local->hw.wiphy);
1152}
1153
1154void ieee80211_sched_scan_stopped_work(struct work_struct *work)
1155{
1156 struct ieee80211_local *local =
1157 container_of(work, struct ieee80211_local,
1158 sched_scan_stopped_work);
1159
1160 ieee80211_sched_scan_end(local);
1161}
1162
1163void ieee80211_sched_scan_stopped(struct ieee80211_hw *hw)
1164{
1165 struct ieee80211_local *local = hw_to_local(hw);
1166
1167 trace_api_sched_scan_stopped(local);
1168
1169 schedule_work(&local->sched_scan_stopped_work);
1170}
1171EXPORT_SYMBOL(ieee80211_sched_scan_stopped);
Linux kernel - Deliverables
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