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Merge tag 'module-builtin_driver-v4.1-rc8' of git://git.kernel.org/pub/scm/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 <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
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 enum nl80211_bss_scan_width scan_width;
71 s32 signal = 0;
72 bool signal_valid;
73
74 if (ieee80211_hw_check(&local->hw, SIGNAL_DBM))
75 signal = rx_status->signal * 100;
76 else if (ieee80211_hw_check(&local->hw, SIGNAL_UNSPEC))
77 signal = (rx_status->signal * 100) / local->hw.max_signal;
78
79 scan_width = NL80211_BSS_CHAN_WIDTH_20;
80 if (rx_status->flag & RX_FLAG_5MHZ)
81 scan_width = NL80211_BSS_CHAN_WIDTH_5;
82 if (rx_status->flag & RX_FLAG_10MHZ)
83 scan_width = NL80211_BSS_CHAN_WIDTH_10;
84
85 cbss = cfg80211_inform_bss_width_frame(local->hw.wiphy, channel,
86 scan_width, mgmt, len, signal,
87 GFP_ATOMIC);
88 if (!cbss)
89 return NULL;
90 /* In case the signal is invalid update the status */
91 signal_valid = abs(channel->center_freq - cbss->channel->center_freq)
92 <= local->hw.wiphy->max_adj_channel_rssi_comp;
93 if (!signal_valid)
94 rx_status->flag |= RX_FLAG_NO_SIGNAL_VAL;
95
96 bss = (void *)cbss->priv;
97
98 if (beacon)
99 bss->device_ts_beacon = rx_status->device_timestamp;
100 else
101 bss->device_ts_presp = rx_status->device_timestamp;
102
103 if (elems->parse_error) {
104 if (beacon)
105 bss->corrupt_data |= IEEE80211_BSS_CORRUPT_BEACON;
106 else
107 bss->corrupt_data |= IEEE80211_BSS_CORRUPT_PROBE_RESP;
108 } else {
109 if (beacon)
110 bss->corrupt_data &= ~IEEE80211_BSS_CORRUPT_BEACON;
111 else
112 bss->corrupt_data &= ~IEEE80211_BSS_CORRUPT_PROBE_RESP;
113 }
114
115 /* save the ERP value so that it is available at association time */
116 if (elems->erp_info && (!elems->parse_error ||
117 !(bss->valid_data & IEEE80211_BSS_VALID_ERP))) {
118 bss->erp_value = elems->erp_info[0];
119 bss->has_erp_value = true;
120 if (!elems->parse_error)
121 bss->valid_data |= IEEE80211_BSS_VALID_ERP;
122 }
123
124 /* replace old supported rates if we get new values */
125 if (!elems->parse_error ||
126 !(bss->valid_data & IEEE80211_BSS_VALID_RATES)) {
127 srlen = 0;
128 if (elems->supp_rates) {
129 clen = IEEE80211_MAX_SUPP_RATES;
130 if (clen > elems->supp_rates_len)
131 clen = elems->supp_rates_len;
132 memcpy(bss->supp_rates, elems->supp_rates, clen);
133 srlen += clen;
134 }
135 if (elems->ext_supp_rates) {
136 clen = IEEE80211_MAX_SUPP_RATES - srlen;
137 if (clen > elems->ext_supp_rates_len)
138 clen = elems->ext_supp_rates_len;
139 memcpy(bss->supp_rates + srlen, elems->ext_supp_rates,
140 clen);
141 srlen += clen;
142 }
143 if (srlen) {
144 bss->supp_rates_len = srlen;
145 if (!elems->parse_error)
146 bss->valid_data |= IEEE80211_BSS_VALID_RATES;
147 }
148 }
149
150 if (!elems->parse_error ||
151 !(bss->valid_data & IEEE80211_BSS_VALID_WMM)) {
152 bss->wmm_used = elems->wmm_param || elems->wmm_info;
153 bss->uapsd_supported = is_uapsd_supported(elems);
154 if (!elems->parse_error)
155 bss->valid_data |= IEEE80211_BSS_VALID_WMM;
156 }
157
158 if (beacon) {
159 struct ieee80211_supported_band *sband =
160 local->hw.wiphy->bands[rx_status->band];
161 if (!(rx_status->flag & RX_FLAG_HT) &&
162 !(rx_status->flag & RX_FLAG_VHT))
163 bss->beacon_rate =
164 &sband->bitrates[rx_status->rate_idx];
165 }
166
167 return bss;
168 }
169
170 void ieee80211_scan_rx(struct ieee80211_local *local, struct sk_buff *skb)
171 {
172 struct ieee80211_rx_status *rx_status = IEEE80211_SKB_RXCB(skb);
173 struct ieee80211_sub_if_data *sdata1, *sdata2;
174 struct ieee80211_mgmt *mgmt = (void *)skb->data;
175 struct ieee80211_bss *bss;
176 u8 *elements;
177 struct ieee80211_channel *channel;
178 size_t baselen;
179 struct ieee802_11_elems elems;
180
181 if (skb->len < 24 ||
182 (!ieee80211_is_probe_resp(mgmt->frame_control) &&
183 !ieee80211_is_beacon(mgmt->frame_control)))
184 return;
185
186 sdata1 = rcu_dereference(local->scan_sdata);
187 sdata2 = rcu_dereference(local->sched_scan_sdata);
188
189 if (likely(!sdata1 && !sdata2))
190 return;
191
192 if (ieee80211_is_probe_resp(mgmt->frame_control)) {
193 struct cfg80211_scan_request *scan_req;
194 struct cfg80211_sched_scan_request *sched_scan_req;
195
196 scan_req = rcu_dereference(local->scan_req);
197 sched_scan_req = rcu_dereference(local->sched_scan_req);
198
199 /* ignore ProbeResp to foreign address unless scanning
200 * with randomised address
201 */
202 if (!(sdata1 &&
203 (ether_addr_equal(mgmt->da, sdata1->vif.addr) ||
204 scan_req->flags & NL80211_SCAN_FLAG_RANDOM_ADDR)) &&
205 !(sdata2 &&
206 (ether_addr_equal(mgmt->da, sdata2->vif.addr) ||
207 sched_scan_req->flags & NL80211_SCAN_FLAG_RANDOM_ADDR)))
208 return;
209
210 elements = mgmt->u.probe_resp.variable;
211 baselen = offsetof(struct ieee80211_mgmt, u.probe_resp.variable);
212 } else {
213 baselen = offsetof(struct ieee80211_mgmt, u.beacon.variable);
214 elements = mgmt->u.beacon.variable;
215 }
216
217 if (baselen > skb->len)
218 return;
219
220 ieee802_11_parse_elems(elements, skb->len - baselen, false, &elems);
221
222 channel = ieee80211_get_channel(local->hw.wiphy, rx_status->freq);
223
224 if (!channel || channel->flags & IEEE80211_CHAN_DISABLED)
225 return;
226
227 bss = ieee80211_bss_info_update(local, rx_status,
228 mgmt, skb->len, &elems,
229 channel);
230 if (bss)
231 ieee80211_rx_bss_put(local, bss);
232 }
233
234 static void
235 ieee80211_prepare_scan_chandef(struct cfg80211_chan_def *chandef,
236 enum nl80211_bss_scan_width scan_width)
237 {
238 memset(chandef, 0, sizeof(*chandef));
239 switch (scan_width) {
240 case NL80211_BSS_CHAN_WIDTH_5:
241 chandef->width = NL80211_CHAN_WIDTH_5;
242 break;
243 case NL80211_BSS_CHAN_WIDTH_10:
244 chandef->width = NL80211_CHAN_WIDTH_10;
245 break;
246 default:
247 chandef->width = NL80211_CHAN_WIDTH_20_NOHT;
248 break;
249 }
250 }
251
252 /* return false if no more work */
253 static bool ieee80211_prep_hw_scan(struct ieee80211_local *local)
254 {
255 struct cfg80211_scan_request *req;
256 struct cfg80211_chan_def chandef;
257 u8 bands_used = 0;
258 int i, ielen, n_chans;
259
260 req = rcu_dereference_protected(local->scan_req,
261 lockdep_is_held(&local->mtx));
262
263 if (test_bit(SCAN_HW_CANCELLED, &local->scanning))
264 return false;
265
266 if (ieee80211_hw_check(&local->hw, SINGLE_SCAN_ON_ALL_BANDS)) {
267 for (i = 0; i < req->n_channels; i++) {
268 local->hw_scan_req->req.channels[i] = req->channels[i];
269 bands_used |= BIT(req->channels[i]->band);
270 }
271
272 n_chans = req->n_channels;
273 } else {
274 do {
275 if (local->hw_scan_band == IEEE80211_NUM_BANDS)
276 return false;
277
278 n_chans = 0;
279
280 for (i = 0; i < req->n_channels; i++) {
281 if (req->channels[i]->band !=
282 local->hw_scan_band)
283 continue;
284 local->hw_scan_req->req.channels[n_chans] =
285 req->channels[i];
286 n_chans++;
287 bands_used |= BIT(req->channels[i]->band);
288 }
289
290 local->hw_scan_band++;
291 } while (!n_chans);
292 }
293
294 local->hw_scan_req->req.n_channels = n_chans;
295 ieee80211_prepare_scan_chandef(&chandef, req->scan_width);
296
297 ielen = ieee80211_build_preq_ies(local,
298 (u8 *)local->hw_scan_req->req.ie,
299 local->hw_scan_ies_bufsize,
300 &local->hw_scan_req->ies,
301 req->ie, req->ie_len,
302 bands_used, req->rates, &chandef);
303 local->hw_scan_req->req.ie_len = ielen;
304 local->hw_scan_req->req.no_cck = req->no_cck;
305 ether_addr_copy(local->hw_scan_req->req.mac_addr, req->mac_addr);
306 ether_addr_copy(local->hw_scan_req->req.mac_addr_mask,
307 req->mac_addr_mask);
308
309 return true;
310 }
311
312 static void __ieee80211_scan_completed(struct ieee80211_hw *hw, bool aborted)
313 {
314 struct ieee80211_local *local = hw_to_local(hw);
315 bool hw_scan = local->ops->hw_scan;
316 bool was_scanning = local->scanning;
317 struct cfg80211_scan_request *scan_req;
318 struct ieee80211_sub_if_data *scan_sdata;
319
320 lockdep_assert_held(&local->mtx);
321
322 /*
323 * It's ok to abort a not-yet-running scan (that
324 * we have one at all will be verified by checking
325 * local->scan_req next), but not to complete it
326 * successfully.
327 */
328 if (WARN_ON(!local->scanning && !aborted))
329 aborted = true;
330
331 if (WARN_ON(!local->scan_req))
332 return;
333
334 if (hw_scan && !aborted &&
335 !ieee80211_hw_check(&local->hw, SINGLE_SCAN_ON_ALL_BANDS) &&
336 ieee80211_prep_hw_scan(local)) {
337 int rc;
338
339 rc = drv_hw_scan(local,
340 rcu_dereference_protected(local->scan_sdata,
341 lockdep_is_held(&local->mtx)),
342 local->hw_scan_req);
343
344 if (rc == 0)
345 return;
346 }
347
348 kfree(local->hw_scan_req);
349 local->hw_scan_req = NULL;
350
351 scan_req = rcu_dereference_protected(local->scan_req,
352 lockdep_is_held(&local->mtx));
353
354 if (scan_req != local->int_scan_req)
355 cfg80211_scan_done(scan_req, aborted);
356 RCU_INIT_POINTER(local->scan_req, NULL);
357
358 scan_sdata = rcu_dereference_protected(local->scan_sdata,
359 lockdep_is_held(&local->mtx));
360 RCU_INIT_POINTER(local->scan_sdata, NULL);
361
362 local->scanning = 0;
363 local->scan_chandef.chan = NULL;
364
365 /* Set power back to normal operating levels. */
366 ieee80211_hw_config(local, 0);
367
368 if (!hw_scan) {
369 ieee80211_configure_filter(local);
370 drv_sw_scan_complete(local, scan_sdata);
371 ieee80211_offchannel_return(local);
372 }
373
374 ieee80211_recalc_idle(local);
375
376 ieee80211_mlme_notify_scan_completed(local);
377 ieee80211_ibss_notify_scan_completed(local);
378 ieee80211_mesh_notify_scan_completed(local);
379 if (was_scanning)
380 ieee80211_start_next_roc(local);
381 }
382
383 void ieee80211_scan_completed(struct ieee80211_hw *hw, bool aborted)
384 {
385 struct ieee80211_local *local = hw_to_local(hw);
386
387 trace_api_scan_completed(local, aborted);
388
389 set_bit(SCAN_COMPLETED, &local->scanning);
390 if (aborted)
391 set_bit(SCAN_ABORTED, &local->scanning);
392 ieee80211_queue_delayed_work(&local->hw, &local->scan_work, 0);
393 }
394 EXPORT_SYMBOL(ieee80211_scan_completed);
395
396 static int ieee80211_start_sw_scan(struct ieee80211_local *local,
397 struct ieee80211_sub_if_data *sdata)
398 {
399 /* Software scan is not supported in multi-channel cases */
400 if (local->use_chanctx)
401 return -EOPNOTSUPP;
402
403 /*
404 * Hardware/driver doesn't support hw_scan, so use software
405 * scanning instead. First send a nullfunc frame with power save
406 * bit on so that AP will buffer the frames for us while we are not
407 * listening, then send probe requests to each channel and wait for
408 * the responses. After all channels are scanned, tune back to the
409 * original channel and send a nullfunc frame with power save bit
410 * off to trigger the AP to send us all the buffered frames.
411 *
412 * Note that while local->sw_scanning is true everything else but
413 * nullfunc frames and probe requests will be dropped in
414 * ieee80211_tx_h_check_assoc().
415 */
416 drv_sw_scan_start(local, sdata, local->scan_addr);
417
418 local->leave_oper_channel_time = jiffies;
419 local->next_scan_state = SCAN_DECISION;
420 local->scan_channel_idx = 0;
421
422 ieee80211_offchannel_stop_vifs(local);
423
424 /* ensure nullfunc is transmitted before leaving operating channel */
425 ieee80211_flush_queues(local, NULL, false);
426
427 ieee80211_configure_filter(local);
428
429 /* We need to set power level at maximum rate for scanning. */
430 ieee80211_hw_config(local, 0);
431
432 ieee80211_queue_delayed_work(&local->hw,
433 &local->scan_work, 0);
434
435 return 0;
436 }
437
438 static bool ieee80211_can_scan(struct ieee80211_local *local,
439 struct ieee80211_sub_if_data *sdata)
440 {
441 if (ieee80211_is_radar_required(local))
442 return false;
443
444 if (!list_empty(&local->roc_list))
445 return false;
446
447 if (sdata->vif.type == NL80211_IFTYPE_STATION &&
448 sdata->u.mgd.flags & IEEE80211_STA_CONNECTION_POLL)
449 return false;
450
451 return true;
452 }
453
454 void ieee80211_run_deferred_scan(struct ieee80211_local *local)
455 {
456 lockdep_assert_held(&local->mtx);
457
458 if (!local->scan_req || local->scanning)
459 return;
460
461 if (!ieee80211_can_scan(local,
462 rcu_dereference_protected(
463 local->scan_sdata,
464 lockdep_is_held(&local->mtx))))
465 return;
466
467 ieee80211_queue_delayed_work(&local->hw, &local->scan_work,
468 round_jiffies_relative(0));
469 }
470
471 static void ieee80211_scan_state_send_probe(struct ieee80211_local *local,
472 unsigned long *next_delay)
473 {
474 int i;
475 struct ieee80211_sub_if_data *sdata;
476 struct cfg80211_scan_request *scan_req;
477 enum ieee80211_band band = local->hw.conf.chandef.chan->band;
478 u32 tx_flags;
479
480 scan_req = rcu_dereference_protected(local->scan_req,
481 lockdep_is_held(&local->mtx));
482
483 tx_flags = IEEE80211_TX_INTFL_OFFCHAN_TX_OK;
484 if (scan_req->no_cck)
485 tx_flags |= IEEE80211_TX_CTL_NO_CCK_RATE;
486
487 sdata = rcu_dereference_protected(local->scan_sdata,
488 lockdep_is_held(&local->mtx));
489
490 for (i = 0; i < scan_req->n_ssids; i++)
491 ieee80211_send_probe_req(
492 sdata, local->scan_addr, NULL,
493 scan_req->ssids[i].ssid, scan_req->ssids[i].ssid_len,
494 scan_req->ie, scan_req->ie_len,
495 scan_req->rates[band], false,
496 tx_flags, local->hw.conf.chandef.chan, true);
497
498 /*
499 * After sending probe requests, wait for probe responses
500 * on the channel.
501 */
502 *next_delay = IEEE80211_CHANNEL_TIME;
503 local->next_scan_state = SCAN_DECISION;
504 }
505
506 static int __ieee80211_start_scan(struct ieee80211_sub_if_data *sdata,
507 struct cfg80211_scan_request *req)
508 {
509 struct ieee80211_local *local = sdata->local;
510 int rc;
511
512 lockdep_assert_held(&local->mtx);
513
514 if (local->scan_req || ieee80211_is_radar_required(local))
515 return -EBUSY;
516
517 if (!ieee80211_can_scan(local, sdata)) {
518 /* wait for the work to finish/time out */
519 rcu_assign_pointer(local->scan_req, req);
520 rcu_assign_pointer(local->scan_sdata, sdata);
521 return 0;
522 }
523
524 if (local->ops->hw_scan) {
525 u8 *ies;
526
527 local->hw_scan_ies_bufsize = local->scan_ies_len + req->ie_len;
528
529 if (ieee80211_hw_check(&local->hw, SINGLE_SCAN_ON_ALL_BANDS)) {
530 int i, n_bands = 0;
531 u8 bands_counted = 0;
532
533 for (i = 0; i < req->n_channels; i++) {
534 if (bands_counted & BIT(req->channels[i]->band))
535 continue;
536 bands_counted |= BIT(req->channels[i]->band);
537 n_bands++;
538 }
539
540 local->hw_scan_ies_bufsize *= n_bands;
541 }
542
543 local->hw_scan_req = kmalloc(
544 sizeof(*local->hw_scan_req) +
545 req->n_channels * sizeof(req->channels[0]) +
546 local->hw_scan_ies_bufsize, GFP_KERNEL);
547 if (!local->hw_scan_req)
548 return -ENOMEM;
549
550 local->hw_scan_req->req.ssids = req->ssids;
551 local->hw_scan_req->req.n_ssids = req->n_ssids;
552 ies = (u8 *)local->hw_scan_req +
553 sizeof(*local->hw_scan_req) +
554 req->n_channels * sizeof(req->channels[0]);
555 local->hw_scan_req->req.ie = ies;
556 local->hw_scan_req->req.flags = req->flags;
557
558 local->hw_scan_band = 0;
559
560 /*
561 * After allocating local->hw_scan_req, we must
562 * go through until ieee80211_prep_hw_scan(), so
563 * anything that might be changed here and leave
564 * this function early must not go after this
565 * allocation.
566 */
567 }
568
569 rcu_assign_pointer(local->scan_req, req);
570 rcu_assign_pointer(local->scan_sdata, sdata);
571
572 if (req->flags & NL80211_SCAN_FLAG_RANDOM_ADDR)
573 get_random_mask_addr(local->scan_addr,
574 req->mac_addr,
575 req->mac_addr_mask);
576 else
577 memcpy(local->scan_addr, sdata->vif.addr, ETH_ALEN);
578
579 if (local->ops->hw_scan) {
580 __set_bit(SCAN_HW_SCANNING, &local->scanning);
581 } else if ((req->n_channels == 1) &&
582 (req->channels[0] == local->_oper_chandef.chan)) {
583 /*
584 * If we are scanning only on the operating channel
585 * then we do not need to stop normal activities
586 */
587 unsigned long next_delay;
588
589 __set_bit(SCAN_ONCHANNEL_SCANNING, &local->scanning);
590
591 ieee80211_recalc_idle(local);
592
593 /* Notify driver scan is starting, keep order of operations
594 * same as normal software scan, in case that matters. */
595 drv_sw_scan_start(local, sdata, local->scan_addr);
596
597 ieee80211_configure_filter(local); /* accept probe-responses */
598
599 /* We need to ensure power level is at max for scanning. */
600 ieee80211_hw_config(local, 0);
601
602 if ((req->channels[0]->flags &
603 IEEE80211_CHAN_NO_IR) ||
604 !req->n_ssids) {
605 next_delay = IEEE80211_PASSIVE_CHANNEL_TIME;
606 } else {
607 ieee80211_scan_state_send_probe(local, &next_delay);
608 next_delay = IEEE80211_CHANNEL_TIME;
609 }
610
611 /* Now, just wait a bit and we are all done! */
612 ieee80211_queue_delayed_work(&local->hw, &local->scan_work,
613 next_delay);
614 return 0;
615 } else {
616 /* Do normal software scan */
617 __set_bit(SCAN_SW_SCANNING, &local->scanning);
618 }
619
620 ieee80211_recalc_idle(local);
621
622 if (local->ops->hw_scan) {
623 WARN_ON(!ieee80211_prep_hw_scan(local));
624 rc = drv_hw_scan(local, sdata, local->hw_scan_req);
625 } else {
626 rc = ieee80211_start_sw_scan(local, sdata);
627 }
628
629 if (rc) {
630 kfree(local->hw_scan_req);
631 local->hw_scan_req = NULL;
632 local->scanning = 0;
633
634 ieee80211_recalc_idle(local);
635
636 local->scan_req = NULL;
637 RCU_INIT_POINTER(local->scan_sdata, NULL);
638 }
639
640 return rc;
641 }
642
643 static unsigned long
644 ieee80211_scan_get_channel_time(struct ieee80211_channel *chan)
645 {
646 /*
647 * TODO: channel switching also consumes quite some time,
648 * add that delay as well to get a better estimation
649 */
650 if (chan->flags & IEEE80211_CHAN_NO_IR)
651 return IEEE80211_PASSIVE_CHANNEL_TIME;
652 return IEEE80211_PROBE_DELAY + IEEE80211_CHANNEL_TIME;
653 }
654
655 static void ieee80211_scan_state_decision(struct ieee80211_local *local,
656 unsigned long *next_delay)
657 {
658 bool associated = false;
659 bool tx_empty = true;
660 bool bad_latency;
661 struct ieee80211_sub_if_data *sdata;
662 struct ieee80211_channel *next_chan;
663 enum mac80211_scan_state next_scan_state;
664 struct cfg80211_scan_request *scan_req;
665
666 /*
667 * check if at least one STA interface is associated,
668 * check if at least one STA interface has pending tx frames
669 * and grab the lowest used beacon interval
670 */
671 mutex_lock(&local->iflist_mtx);
672 list_for_each_entry(sdata, &local->interfaces, list) {
673 if (!ieee80211_sdata_running(sdata))
674 continue;
675
676 if (sdata->vif.type == NL80211_IFTYPE_STATION) {
677 if (sdata->u.mgd.associated) {
678 associated = true;
679
680 if (!qdisc_all_tx_empty(sdata->dev)) {
681 tx_empty = false;
682 break;
683 }
684 }
685 }
686 }
687 mutex_unlock(&local->iflist_mtx);
688
689 scan_req = rcu_dereference_protected(local->scan_req,
690 lockdep_is_held(&local->mtx));
691
692 next_chan = scan_req->channels[local->scan_channel_idx];
693
694 /*
695 * we're currently scanning a different channel, let's
696 * see if we can scan another channel without interfering
697 * with the current traffic situation.
698 *
699 * Keep good latency, do not stay off-channel more than 125 ms.
700 */
701
702 bad_latency = time_after(jiffies +
703 ieee80211_scan_get_channel_time(next_chan),
704 local->leave_oper_channel_time + HZ / 8);
705
706 if (associated && !tx_empty) {
707 if (scan_req->flags & NL80211_SCAN_FLAG_LOW_PRIORITY)
708 next_scan_state = SCAN_ABORT;
709 else
710 next_scan_state = SCAN_SUSPEND;
711 } else if (associated && bad_latency) {
712 next_scan_state = SCAN_SUSPEND;
713 } else {
714 next_scan_state = SCAN_SET_CHANNEL;
715 }
716
717 local->next_scan_state = next_scan_state;
718
719 *next_delay = 0;
720 }
721
722 static void ieee80211_scan_state_set_channel(struct ieee80211_local *local,
723 unsigned long *next_delay)
724 {
725 int skip;
726 struct ieee80211_channel *chan;
727 enum nl80211_bss_scan_width oper_scan_width;
728 struct cfg80211_scan_request *scan_req;
729
730 scan_req = rcu_dereference_protected(local->scan_req,
731 lockdep_is_held(&local->mtx));
732
733 skip = 0;
734 chan = scan_req->channels[local->scan_channel_idx];
735
736 local->scan_chandef.chan = chan;
737 local->scan_chandef.center_freq1 = chan->center_freq;
738 local->scan_chandef.center_freq2 = 0;
739 switch (scan_req->scan_width) {
740 case NL80211_BSS_CHAN_WIDTH_5:
741 local->scan_chandef.width = NL80211_CHAN_WIDTH_5;
742 break;
743 case NL80211_BSS_CHAN_WIDTH_10:
744 local->scan_chandef.width = NL80211_CHAN_WIDTH_10;
745 break;
746 case NL80211_BSS_CHAN_WIDTH_20:
747 /* If scanning on oper channel, use whatever channel-type
748 * is currently in use.
749 */
750 oper_scan_width = cfg80211_chandef_to_scan_width(
751 &local->_oper_chandef);
752 if (chan == local->_oper_chandef.chan &&
753 oper_scan_width == scan_req->scan_width)
754 local->scan_chandef = local->_oper_chandef;
755 else
756 local->scan_chandef.width = NL80211_CHAN_WIDTH_20_NOHT;
757 break;
758 }
759
760 if (ieee80211_hw_config(local, IEEE80211_CONF_CHANGE_CHANNEL))
761 skip = 1;
762
763 /* advance state machine to next channel/band */
764 local->scan_channel_idx++;
765
766 if (skip) {
767 /* if we skip this channel return to the decision state */
768 local->next_scan_state = SCAN_DECISION;
769 return;
770 }
771
772 /*
773 * Probe delay is used to update the NAV, cf. 11.1.3.2.2
774 * (which unfortunately doesn't say _why_ step a) is done,
775 * but it waits for the probe delay or until a frame is
776 * received - and the received frame would update the NAV).
777 * For now, we do not support waiting until a frame is
778 * received.
779 *
780 * In any case, it is not necessary for a passive scan.
781 */
782 if (chan->flags & IEEE80211_CHAN_NO_IR || !scan_req->n_ssids) {
783 *next_delay = IEEE80211_PASSIVE_CHANNEL_TIME;
784 local->next_scan_state = SCAN_DECISION;
785 return;
786 }
787
788 /* active scan, send probes */
789 *next_delay = IEEE80211_PROBE_DELAY;
790 local->next_scan_state = SCAN_SEND_PROBE;
791 }
792
793 static void ieee80211_scan_state_suspend(struct ieee80211_local *local,
794 unsigned long *next_delay)
795 {
796 /* switch back to the operating channel */
797 local->scan_chandef.chan = NULL;
798 ieee80211_hw_config(local, IEEE80211_CONF_CHANGE_CHANNEL);
799
800 /* disable PS */
801 ieee80211_offchannel_return(local);
802
803 *next_delay = HZ / 5;
804 /* afterwards, resume scan & go to next channel */
805 local->next_scan_state = SCAN_RESUME;
806 }
807
808 static void ieee80211_scan_state_resume(struct ieee80211_local *local,
809 unsigned long *next_delay)
810 {
811 ieee80211_offchannel_stop_vifs(local);
812
813 if (local->ops->flush) {
814 ieee80211_flush_queues(local, NULL, false);
815 *next_delay = 0;
816 } else
817 *next_delay = HZ / 10;
818
819 /* remember when we left the operating channel */
820 local->leave_oper_channel_time = jiffies;
821
822 /* advance to the next channel to be scanned */
823 local->next_scan_state = SCAN_SET_CHANNEL;
824 }
825
826 void ieee80211_scan_work(struct work_struct *work)
827 {
828 struct ieee80211_local *local =
829 container_of(work, struct ieee80211_local, scan_work.work);
830 struct ieee80211_sub_if_data *sdata;
831 struct cfg80211_scan_request *scan_req;
832 unsigned long next_delay = 0;
833 bool aborted;
834
835 mutex_lock(&local->mtx);
836
837 if (!ieee80211_can_run_worker(local)) {
838 aborted = true;
839 goto out_complete;
840 }
841
842 sdata = rcu_dereference_protected(local->scan_sdata,
843 lockdep_is_held(&local->mtx));
844 scan_req = rcu_dereference_protected(local->scan_req,
845 lockdep_is_held(&local->mtx));
846
847 /* When scanning on-channel, the first-callback means completed. */
848 if (test_bit(SCAN_ONCHANNEL_SCANNING, &local->scanning)) {
849 aborted = test_and_clear_bit(SCAN_ABORTED, &local->scanning);
850 goto out_complete;
851 }
852
853 if (test_and_clear_bit(SCAN_COMPLETED, &local->scanning)) {
854 aborted = test_and_clear_bit(SCAN_ABORTED, &local->scanning);
855 goto out_complete;
856 }
857
858 if (!sdata || !scan_req)
859 goto out;
860
861 if (!local->scanning) {
862 int rc;
863
864 RCU_INIT_POINTER(local->scan_req, NULL);
865 RCU_INIT_POINTER(local->scan_sdata, NULL);
866
867 rc = __ieee80211_start_scan(sdata, scan_req);
868 if (rc) {
869 /* need to complete scan in cfg80211 */
870 rcu_assign_pointer(local->scan_req, scan_req);
871 aborted = true;
872 goto out_complete;
873 } else
874 goto out;
875 }
876
877 /*
878 * as long as no delay is required advance immediately
879 * without scheduling a new work
880 */
881 do {
882 if (!ieee80211_sdata_running(sdata)) {
883 aborted = true;
884 goto out_complete;
885 }
886
887 switch (local->next_scan_state) {
888 case SCAN_DECISION:
889 /* if no more bands/channels left, complete scan */
890 if (local->scan_channel_idx >= scan_req->n_channels) {
891 aborted = false;
892 goto out_complete;
893 }
894 ieee80211_scan_state_decision(local, &next_delay);
895 break;
896 case SCAN_SET_CHANNEL:
897 ieee80211_scan_state_set_channel(local, &next_delay);
898 break;
899 case SCAN_SEND_PROBE:
900 ieee80211_scan_state_send_probe(local, &next_delay);
901 break;
902 case SCAN_SUSPEND:
903 ieee80211_scan_state_suspend(local, &next_delay);
904 break;
905 case SCAN_RESUME:
906 ieee80211_scan_state_resume(local, &next_delay);
907 break;
908 case SCAN_ABORT:
909 aborted = true;
910 goto out_complete;
911 }
912 } while (next_delay == 0);
913
914 ieee80211_queue_delayed_work(&local->hw, &local->scan_work, next_delay);
915 goto out;
916
917 out_complete:
918 __ieee80211_scan_completed(&local->hw, aborted);
919 out:
920 mutex_unlock(&local->mtx);
921 }
922
923 int ieee80211_request_scan(struct ieee80211_sub_if_data *sdata,
924 struct cfg80211_scan_request *req)
925 {
926 int res;
927
928 mutex_lock(&sdata->local->mtx);
929 res = __ieee80211_start_scan(sdata, req);
930 mutex_unlock(&sdata->local->mtx);
931
932 return res;
933 }
934
935 int ieee80211_request_ibss_scan(struct ieee80211_sub_if_data *sdata,
936 const u8 *ssid, u8 ssid_len,
937 struct ieee80211_channel **channels,
938 unsigned int n_channels,
939 enum nl80211_bss_scan_width scan_width)
940 {
941 struct ieee80211_local *local = sdata->local;
942 int ret = -EBUSY, i, n_ch = 0;
943 enum ieee80211_band band;
944
945 mutex_lock(&local->mtx);
946
947 /* busy scanning */
948 if (local->scan_req)
949 goto unlock;
950
951 /* fill internal scan request */
952 if (!channels) {
953 int max_n;
954
955 for (band = 0; band < IEEE80211_NUM_BANDS; band++) {
956 if (!local->hw.wiphy->bands[band])
957 continue;
958
959 max_n = local->hw.wiphy->bands[band]->n_channels;
960 for (i = 0; i < max_n; i++) {
961 struct ieee80211_channel *tmp_ch =
962 &local->hw.wiphy->bands[band]->channels[i];
963
964 if (tmp_ch->flags & (IEEE80211_CHAN_NO_IR |
965 IEEE80211_CHAN_DISABLED))
966 continue;
967
968 local->int_scan_req->channels[n_ch] = tmp_ch;
969 n_ch++;
970 }
971 }
972
973 if (WARN_ON_ONCE(n_ch == 0))
974 goto unlock;
975
976 local->int_scan_req->n_channels = n_ch;
977 } else {
978 for (i = 0; i < n_channels; i++) {
979 if (channels[i]->flags & (IEEE80211_CHAN_NO_IR |
980 IEEE80211_CHAN_DISABLED))
981 continue;
982
983 local->int_scan_req->channels[n_ch] = channels[i];
984 n_ch++;
985 }
986
987 if (WARN_ON_ONCE(n_ch == 0))
988 goto unlock;
989
990 local->int_scan_req->n_channels = n_ch;
991 }
992
993 local->int_scan_req->ssids = &local->scan_ssid;
994 local->int_scan_req->n_ssids = 1;
995 local->int_scan_req->scan_width = scan_width;
996 memcpy(local->int_scan_req->ssids[0].ssid, ssid, IEEE80211_MAX_SSID_LEN);
997 local->int_scan_req->ssids[0].ssid_len = ssid_len;
998
999 ret = __ieee80211_start_scan(sdata, sdata->local->int_scan_req);
1000 unlock:
1001 mutex_unlock(&local->mtx);
1002 return ret;
1003 }
1004
1005 /*
1006 * Only call this function when a scan can't be queued -- under RTNL.
1007 */
1008 void ieee80211_scan_cancel(struct ieee80211_local *local)
1009 {
1010 /*
1011 * We are canceling software scan, or deferred scan that was not
1012 * yet really started (see __ieee80211_start_scan ).
1013 *
1014 * Regarding hardware scan:
1015 * - we can not call __ieee80211_scan_completed() as when
1016 * SCAN_HW_SCANNING bit is set this function change
1017 * local->hw_scan_req to operate on 5G band, what race with
1018 * driver which can use local->hw_scan_req
1019 *
1020 * - we can not cancel scan_work since driver can schedule it
1021 * by ieee80211_scan_completed(..., true) to finish scan
1022 *
1023 * Hence we only call the cancel_hw_scan() callback, but the low-level
1024 * driver is still responsible for calling ieee80211_scan_completed()
1025 * after the scan was completed/aborted.
1026 */
1027
1028 mutex_lock(&local->mtx);
1029 if (!local->scan_req)
1030 goto out;
1031
1032 /*
1033 * We have a scan running and the driver already reported completion,
1034 * but the worker hasn't run yet or is stuck on the mutex - mark it as
1035 * cancelled.
1036 */
1037 if (test_bit(SCAN_HW_SCANNING, &local->scanning) &&
1038 test_bit(SCAN_COMPLETED, &local->scanning)) {
1039 set_bit(SCAN_HW_CANCELLED, &local->scanning);
1040 goto out;
1041 }
1042
1043 if (test_bit(SCAN_HW_SCANNING, &local->scanning)) {
1044 /*
1045 * Make sure that __ieee80211_scan_completed doesn't trigger a
1046 * scan on another band.
1047 */
1048 set_bit(SCAN_HW_CANCELLED, &local->scanning);
1049 if (local->ops->cancel_hw_scan)
1050 drv_cancel_hw_scan(local,
1051 rcu_dereference_protected(local->scan_sdata,
1052 lockdep_is_held(&local->mtx)));
1053 goto out;
1054 }
1055
1056 /*
1057 * If the work is currently running, it must be blocked on
1058 * the mutex, but we'll set scan_sdata = NULL and it'll
1059 * simply exit once it acquires the mutex.
1060 */
1061 cancel_delayed_work(&local->scan_work);
1062 /* and clean up */
1063 __ieee80211_scan_completed(&local->hw, true);
1064 out:
1065 mutex_unlock(&local->mtx);
1066 }
1067
1068 int __ieee80211_request_sched_scan_start(struct ieee80211_sub_if_data *sdata,
1069 struct cfg80211_sched_scan_request *req)
1070 {
1071 struct ieee80211_local *local = sdata->local;
1072 struct ieee80211_scan_ies sched_scan_ies = {};
1073 struct cfg80211_chan_def chandef;
1074 int ret, i, iebufsz, num_bands = 0;
1075 u32 rate_masks[IEEE80211_NUM_BANDS] = {};
1076 u8 bands_used = 0;
1077 u8 *ie;
1078 size_t len;
1079
1080 iebufsz = local->scan_ies_len + req->ie_len;
1081
1082 lockdep_assert_held(&local->mtx);
1083
1084 if (!local->ops->sched_scan_start)
1085 return -ENOTSUPP;
1086
1087 for (i = 0; i < IEEE80211_NUM_BANDS; i++) {
1088 if (local->hw.wiphy->bands[i]) {
1089 bands_used |= BIT(i);
1090 rate_masks[i] = (u32) -1;
1091 num_bands++;
1092 }
1093 }
1094
1095 ie = kzalloc(num_bands * iebufsz, GFP_KERNEL);
1096 if (!ie) {
1097 ret = -ENOMEM;
1098 goto out;
1099 }
1100
1101 ieee80211_prepare_scan_chandef(&chandef, req->scan_width);
1102
1103 len = ieee80211_build_preq_ies(local, ie, num_bands * iebufsz,
1104 &sched_scan_ies, req->ie,
1105 req->ie_len, bands_used,
1106 rate_masks, &chandef);
1107
1108 ret = drv_sched_scan_start(local, sdata, req, &sched_scan_ies);
1109 if (ret == 0) {
1110 rcu_assign_pointer(local->sched_scan_sdata, sdata);
1111 rcu_assign_pointer(local->sched_scan_req, req);
1112 }
1113
1114 kfree(ie);
1115
1116 out:
1117 if (ret) {
1118 /* Clean in case of failure after HW restart or upon resume. */
1119 RCU_INIT_POINTER(local->sched_scan_sdata, NULL);
1120 RCU_INIT_POINTER(local->sched_scan_req, NULL);
1121 }
1122
1123 return ret;
1124 }
1125
1126 int ieee80211_request_sched_scan_start(struct ieee80211_sub_if_data *sdata,
1127 struct cfg80211_sched_scan_request *req)
1128 {
1129 struct ieee80211_local *local = sdata->local;
1130 int ret;
1131
1132 mutex_lock(&local->mtx);
1133
1134 if (rcu_access_pointer(local->sched_scan_sdata)) {
1135 mutex_unlock(&local->mtx);
1136 return -EBUSY;
1137 }
1138
1139 ret = __ieee80211_request_sched_scan_start(sdata, req);
1140
1141 mutex_unlock(&local->mtx);
1142 return ret;
1143 }
1144
1145 int ieee80211_request_sched_scan_stop(struct ieee80211_sub_if_data *sdata)
1146 {
1147 struct ieee80211_local *local = sdata->local;
1148 int ret = 0;
1149
1150 mutex_lock(&local->mtx);
1151
1152 if (!local->ops->sched_scan_stop) {
1153 ret = -ENOTSUPP;
1154 goto out;
1155 }
1156
1157 /* We don't want to restart sched scan anymore. */
1158 RCU_INIT_POINTER(local->sched_scan_req, NULL);
1159
1160 if (rcu_access_pointer(local->sched_scan_sdata)) {
1161 ret = drv_sched_scan_stop(local, sdata);
1162 if (!ret)
1163 RCU_INIT_POINTER(local->sched_scan_sdata, NULL);
1164 }
1165 out:
1166 mutex_unlock(&local->mtx);
1167
1168 return ret;
1169 }
1170
1171 void ieee80211_sched_scan_results(struct ieee80211_hw *hw)
1172 {
1173 struct ieee80211_local *local = hw_to_local(hw);
1174
1175 trace_api_sched_scan_results(local);
1176
1177 cfg80211_sched_scan_results(hw->wiphy);
1178 }
1179 EXPORT_SYMBOL(ieee80211_sched_scan_results);
1180
1181 void ieee80211_sched_scan_end(struct ieee80211_local *local)
1182 {
1183 mutex_lock(&local->mtx);
1184
1185 if (!rcu_access_pointer(local->sched_scan_sdata)) {
1186 mutex_unlock(&local->mtx);
1187 return;
1188 }
1189
1190 RCU_INIT_POINTER(local->sched_scan_sdata, NULL);
1191
1192 /* If sched scan was aborted by the driver. */
1193 RCU_INIT_POINTER(local->sched_scan_req, NULL);
1194
1195 mutex_unlock(&local->mtx);
1196
1197 cfg80211_sched_scan_stopped(local->hw.wiphy);
1198 }
1199
1200 void ieee80211_sched_scan_stopped_work(struct work_struct *work)
1201 {
1202 struct ieee80211_local *local =
1203 container_of(work, struct ieee80211_local,
1204 sched_scan_stopped_work);
1205
1206 ieee80211_sched_scan_end(local);
1207 }
1208
1209 void ieee80211_sched_scan_stopped(struct ieee80211_hw *hw)
1210 {
1211 struct ieee80211_local *local = hw_to_local(hw);
1212
1213 trace_api_sched_scan_stopped(local);
1214
1215 schedule_work(&local->sched_scan_stopped_work);
1216 }
1217 EXPORT_SYMBOL(ieee80211_sched_scan_stopped);
Linux kernel - Deliverables
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