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Merge commit 'linus' into x86/urgent, to pick up recent x86 changes
[linux-2.6/btrfs-unstable.git] / net / mac80211 / scan.c
bloba413e52f7691418116d928f684a0fc27b308c2d6
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
318 lockdep_assert_held(&local->mtx);
319
320 /*
321 * It's ok to abort a not-yet-running scan (that
322 * we have one at all will be verified by checking
323 * local->scan_req next), but not to complete it
324 * successfully.
325 */
326 if (WARN_ON(!local->scanning && !aborted))
327 aborted = true;
328
329 if (WARN_ON(!local->scan_req))
330 return;
331
332 if (hw_scan && !aborted &&
333 !ieee80211_hw_check(&local->hw, SINGLE_SCAN_ON_ALL_BANDS) &&
334 ieee80211_prep_hw_scan(local)) {
335 int rc;
336
337 rc = drv_hw_scan(local,
338 rcu_dereference_protected(local->scan_sdata,
339 lockdep_is_held(&local->mtx)),
340 local->hw_scan_req);
341
342 if (rc == 0)
343 return;
344 }
345
346 kfree(local->hw_scan_req);
347 local->hw_scan_req = NULL;
348
349 scan_req = rcu_dereference_protected(local->scan_req,
350 lockdep_is_held(&local->mtx));
351
352 if (scan_req != local->int_scan_req)
353 cfg80211_scan_done(scan_req, aborted);
354 RCU_INIT_POINTER(local->scan_req, NULL);
355
356 scan_sdata = rcu_dereference_protected(local->scan_sdata,
357 lockdep_is_held(&local->mtx));
358 RCU_INIT_POINTER(local->scan_sdata, NULL);
359
360 local->scanning = 0;
361 local->scan_chandef.chan = NULL;
362
363 /* Set power back to normal operating levels. */
364 ieee80211_hw_config(local, 0);
365
366 if (!hw_scan) {
367 ieee80211_configure_filter(local);
368 drv_sw_scan_complete(local, scan_sdata);
369 ieee80211_offchannel_return(local);
370 }
371
372 ieee80211_recalc_idle(local);
373
374 ieee80211_mlme_notify_scan_completed(local);
375 ieee80211_ibss_notify_scan_completed(local);
376 ieee80211_mesh_notify_scan_completed(local);
377 if (was_scanning)
378 ieee80211_start_next_roc(local);
379 }
380
381 void ieee80211_scan_completed(struct ieee80211_hw *hw, bool aborted)
382 {
383 struct ieee80211_local *local = hw_to_local(hw);
384
385 trace_api_scan_completed(local, aborted);
386
387 set_bit(SCAN_COMPLETED, &local->scanning);
388 if (aborted)
389 set_bit(SCAN_ABORTED, &local->scanning);
390 ieee80211_queue_delayed_work(&local->hw, &local->scan_work, 0);
391 }
392 EXPORT_SYMBOL(ieee80211_scan_completed);
393
394 static int ieee80211_start_sw_scan(struct ieee80211_local *local,
395 struct ieee80211_sub_if_data *sdata)
396 {
397 /* Software scan is not supported in multi-channel cases */
398 if (local->use_chanctx)
399 return -EOPNOTSUPP;
400
401 /*
402 * Hardware/driver doesn't support hw_scan, so use software
403 * scanning instead. First send a nullfunc frame with power save
404 * bit on so that AP will buffer the frames for us while we are not
405 * listening, then send probe requests to each channel and wait for
406 * the responses. After all channels are scanned, tune back to the
407 * original channel and send a nullfunc frame with power save bit
408 * off to trigger the AP to send us all the buffered frames.
409 *
410 * Note that while local->sw_scanning is true everything else but
411 * nullfunc frames and probe requests will be dropped in
412 * ieee80211_tx_h_check_assoc().
413 */
414 drv_sw_scan_start(local, sdata, local->scan_addr);
415
416 local->leave_oper_channel_time = jiffies;
417 local->next_scan_state = SCAN_DECISION;
418 local->scan_channel_idx = 0;
419
420 ieee80211_offchannel_stop_vifs(local);
421
422 /* ensure nullfunc is transmitted before leaving operating channel */
423 ieee80211_flush_queues(local, NULL, false);
424
425 ieee80211_configure_filter(local);
426
427 /* We need to set power level at maximum rate for scanning. */
428 ieee80211_hw_config(local, 0);
429
430 ieee80211_queue_delayed_work(&local->hw,
431 &local->scan_work, 0);
432
433 return 0;
434 }
435
436 static bool ieee80211_can_scan(struct ieee80211_local *local,
437 struct ieee80211_sub_if_data *sdata)
438 {
439 if (ieee80211_is_radar_required(local))
440 return false;
441
442 if (!list_empty(&local->roc_list))
443 return false;
444
445 if (sdata->vif.type == NL80211_IFTYPE_STATION &&
446 sdata->u.mgd.flags & IEEE80211_STA_CONNECTION_POLL)
447 return false;
448
449 return true;
450 }
451
452 void ieee80211_run_deferred_scan(struct ieee80211_local *local)
453 {
454 lockdep_assert_held(&local->mtx);
455
456 if (!local->scan_req || local->scanning)
457 return;
458
459 if (!ieee80211_can_scan(local,
460 rcu_dereference_protected(
461 local->scan_sdata,
462 lockdep_is_held(&local->mtx))))
463 return;
464
465 ieee80211_queue_delayed_work(&local->hw, &local->scan_work,
466 round_jiffies_relative(0));
467 }
468
469 static void ieee80211_scan_state_send_probe(struct ieee80211_local *local,
470 unsigned long *next_delay)
471 {
472 int i;
473 struct ieee80211_sub_if_data *sdata;
474 struct cfg80211_scan_request *scan_req;
475 enum ieee80211_band band = local->hw.conf.chandef.chan->band;
476 u32 tx_flags;
477
478 scan_req = rcu_dereference_protected(local->scan_req,
479 lockdep_is_held(&local->mtx));
480
481 tx_flags = IEEE80211_TX_INTFL_OFFCHAN_TX_OK;
482 if (scan_req->no_cck)
483 tx_flags |= IEEE80211_TX_CTL_NO_CCK_RATE;
484
485 sdata = rcu_dereference_protected(local->scan_sdata,
486 lockdep_is_held(&local->mtx));
487
488 for (i = 0; i < scan_req->n_ssids; i++)
489 ieee80211_send_probe_req(
490 sdata, local->scan_addr, NULL,
491 scan_req->ssids[i].ssid, scan_req->ssids[i].ssid_len,
492 scan_req->ie, scan_req->ie_len,
493 scan_req->rates[band], false,
494 tx_flags, local->hw.conf.chandef.chan, true);
495
496 /*
497 * After sending probe requests, wait for probe responses
498 * on the channel.
499 */
500 *next_delay = IEEE80211_CHANNEL_TIME;
501 local->next_scan_state = SCAN_DECISION;
502 }
503
504 static int __ieee80211_start_scan(struct ieee80211_sub_if_data *sdata,
505 struct cfg80211_scan_request *req)
506 {
507 struct ieee80211_local *local = sdata->local;
508 int rc;
509
510 lockdep_assert_held(&local->mtx);
511
512 if (local->scan_req || ieee80211_is_radar_required(local))
513 return -EBUSY;
514
515 if (!ieee80211_can_scan(local, sdata)) {
516 /* wait for the work to finish/time out */
517 rcu_assign_pointer(local->scan_req, req);
518 rcu_assign_pointer(local->scan_sdata, sdata);
519 return 0;
520 }
521
522 if (local->ops->hw_scan) {
523 u8 *ies;
524
525 local->hw_scan_ies_bufsize = local->scan_ies_len + req->ie_len;
526
527 if (ieee80211_hw_check(&local->hw, SINGLE_SCAN_ON_ALL_BANDS)) {
528 int i, n_bands = 0;
529 u8 bands_counted = 0;
530
531 for (i = 0; i < req->n_channels; i++) {
532 if (bands_counted & BIT(req->channels[i]->band))
533 continue;
534 bands_counted |= BIT(req->channels[i]->band);
535 n_bands++;
536 }
537
538 local->hw_scan_ies_bufsize *= n_bands;
539 }
540
541 local->hw_scan_req = kmalloc(
542 sizeof(*local->hw_scan_req) +
543 req->n_channels * sizeof(req->channels[0]) +
544 local->hw_scan_ies_bufsize, GFP_KERNEL);
545 if (!local->hw_scan_req)
546 return -ENOMEM;
547
548 local->hw_scan_req->req.ssids = req->ssids;
549 local->hw_scan_req->req.n_ssids = req->n_ssids;
550 ies = (u8 *)local->hw_scan_req +
551 sizeof(*local->hw_scan_req) +
552 req->n_channels * sizeof(req->channels[0]);
553 local->hw_scan_req->req.ie = ies;
554 local->hw_scan_req->req.flags = req->flags;
555
556 local->hw_scan_band = 0;
557
558 /*
559 * After allocating local->hw_scan_req, we must
560 * go through until ieee80211_prep_hw_scan(), so
561 * anything that might be changed here and leave
562 * this function early must not go after this
563 * allocation.
564 */
565 }
566
567 rcu_assign_pointer(local->scan_req, req);
568 rcu_assign_pointer(local->scan_sdata, sdata);
569
570 if (req->flags & NL80211_SCAN_FLAG_RANDOM_ADDR)
571 get_random_mask_addr(local->scan_addr,
572 req->mac_addr,
573 req->mac_addr_mask);
574 else
575 memcpy(local->scan_addr, sdata->vif.addr, ETH_ALEN);
576
577 if (local->ops->hw_scan) {
578 __set_bit(SCAN_HW_SCANNING, &local->scanning);
579 } else if ((req->n_channels == 1) &&
580 (req->channels[0] == local->_oper_chandef.chan)) {
581 /*
582 * If we are scanning only on the operating channel
583 * then we do not need to stop normal activities
584 */
585 unsigned long next_delay;
586
587 __set_bit(SCAN_ONCHANNEL_SCANNING, &local->scanning);
588
589 ieee80211_recalc_idle(local);
590
591 /* Notify driver scan is starting, keep order of operations
592 * same as normal software scan, in case that matters. */
593 drv_sw_scan_start(local, sdata, local->scan_addr);
594
595 ieee80211_configure_filter(local); /* accept probe-responses */
596
597 /* We need to ensure power level is at max for scanning. */
598 ieee80211_hw_config(local, 0);
599
600 if ((req->channels[0]->flags & (IEEE80211_CHAN_NO_IR |
601 IEEE80211_CHAN_RADAR)) ||
602 !req->n_ssids) {
603 next_delay = IEEE80211_PASSIVE_CHANNEL_TIME;
604 } else {
605 ieee80211_scan_state_send_probe(local, &next_delay);
606 next_delay = IEEE80211_CHANNEL_TIME;
607 }
608
609 /* Now, just wait a bit and we are all done! */
610 ieee80211_queue_delayed_work(&local->hw, &local->scan_work,
611 next_delay);
612 return 0;
613 } else {
614 /* Do normal software scan */
615 __set_bit(SCAN_SW_SCANNING, &local->scanning);
616 }
617
618 ieee80211_recalc_idle(local);
619
620 if (local->ops->hw_scan) {
621 WARN_ON(!ieee80211_prep_hw_scan(local));
622 rc = drv_hw_scan(local, sdata, local->hw_scan_req);
623 } else {
624 rc = ieee80211_start_sw_scan(local, sdata);
625 }
626
627 if (rc) {
628 kfree(local->hw_scan_req);
629 local->hw_scan_req = NULL;
630 local->scanning = 0;
631
632 ieee80211_recalc_idle(local);
633
634 local->scan_req = NULL;
635 RCU_INIT_POINTER(local->scan_sdata, NULL);
636 }
637
638 return rc;
639 }
640
641 static unsigned long
642 ieee80211_scan_get_channel_time(struct ieee80211_channel *chan)
643 {
644 /*
645 * TODO: channel switching also consumes quite some time,
646 * add that delay as well to get a better estimation
647 */
648 if (chan->flags & (IEEE80211_CHAN_NO_IR | IEEE80211_CHAN_RADAR))
649 return IEEE80211_PASSIVE_CHANNEL_TIME;
650 return IEEE80211_PROBE_DELAY + IEEE80211_CHANNEL_TIME;
651 }
652
653 static void ieee80211_scan_state_decision(struct ieee80211_local *local,
654 unsigned long *next_delay)
655 {
656 bool associated = false;
657 bool tx_empty = true;
658 bool bad_latency;
659 struct ieee80211_sub_if_data *sdata;
660 struct ieee80211_channel *next_chan;
661 enum mac80211_scan_state next_scan_state;
662 struct cfg80211_scan_request *scan_req;
663
664 /*
665 * check if at least one STA interface is associated,
666 * check if at least one STA interface has pending tx frames
667 * and grab the lowest used beacon interval
668 */
669 mutex_lock(&local->iflist_mtx);
670 list_for_each_entry(sdata, &local->interfaces, list) {
671 if (!ieee80211_sdata_running(sdata))
672 continue;
673
674 if (sdata->vif.type == NL80211_IFTYPE_STATION) {
675 if (sdata->u.mgd.associated) {
676 associated = true;
677
678 if (!qdisc_all_tx_empty(sdata->dev)) {
679 tx_empty = false;
680 break;
681 }
682 }
683 }
684 }
685 mutex_unlock(&local->iflist_mtx);
686
687 scan_req = rcu_dereference_protected(local->scan_req,
688 lockdep_is_held(&local->mtx));
689
690 next_chan = scan_req->channels[local->scan_channel_idx];
691
692 /*
693 * we're currently scanning a different channel, let's
694 * see if we can scan another channel without interfering
695 * with the current traffic situation.
696 *
697 * Keep good latency, do not stay off-channel more than 125 ms.
698 */
699
700 bad_latency = time_after(jiffies +
701 ieee80211_scan_get_channel_time(next_chan),
702 local->leave_oper_channel_time + HZ / 8);
703
704 if (associated && !tx_empty) {
705 if (scan_req->flags & NL80211_SCAN_FLAG_LOW_PRIORITY)
706 next_scan_state = SCAN_ABORT;
707 else
708 next_scan_state = SCAN_SUSPEND;
709 } else if (associated && bad_latency) {
710 next_scan_state = SCAN_SUSPEND;
711 } else {
712 next_scan_state = SCAN_SET_CHANNEL;
713 }
714
715 local->next_scan_state = next_scan_state;
716
717 *next_delay = 0;
718 }
719
720 static void ieee80211_scan_state_set_channel(struct ieee80211_local *local,
721 unsigned long *next_delay)
722 {
723 int skip;
724 struct ieee80211_channel *chan;
725 enum nl80211_bss_scan_width oper_scan_width;
726 struct cfg80211_scan_request *scan_req;
727
728 scan_req = rcu_dereference_protected(local->scan_req,
729 lockdep_is_held(&local->mtx));
730
731 skip = 0;
732 chan = scan_req->channels[local->scan_channel_idx];
733
734 local->scan_chandef.chan = chan;
735 local->scan_chandef.center_freq1 = chan->center_freq;
736 local->scan_chandef.center_freq2 = 0;
737 switch (scan_req->scan_width) {
738 case NL80211_BSS_CHAN_WIDTH_5:
739 local->scan_chandef.width = NL80211_CHAN_WIDTH_5;
740 break;
741 case NL80211_BSS_CHAN_WIDTH_10:
742 local->scan_chandef.width = NL80211_CHAN_WIDTH_10;
743 break;
744 case NL80211_BSS_CHAN_WIDTH_20:
745 /* If scanning on oper channel, use whatever channel-type
746 * is currently in use.
747 */
748 oper_scan_width = cfg80211_chandef_to_scan_width(
749 &local->_oper_chandef);
750 if (chan == local->_oper_chandef.chan &&
751 oper_scan_width == scan_req->scan_width)
752 local->scan_chandef = local->_oper_chandef;
753 else
754 local->scan_chandef.width = NL80211_CHAN_WIDTH_20_NOHT;
755 break;
756 }
757
758 if (ieee80211_hw_config(local, IEEE80211_CONF_CHANGE_CHANNEL))
759 skip = 1;
760
761 /* advance state machine to next channel/band */
762 local->scan_channel_idx++;
763
764 if (skip) {
765 /* if we skip this channel return to the decision state */
766 local->next_scan_state = SCAN_DECISION;
767 return;
768 }
769
770 /*
771 * Probe delay is used to update the NAV, cf. 11.1.3.2.2
772 * (which unfortunately doesn't say _why_ step a) is done,
773 * but it waits for the probe delay or until a frame is
774 * received - and the received frame would update the NAV).
775 * For now, we do not support waiting until a frame is
776 * received.
777 *
778 * In any case, it is not necessary for a passive scan.
779 */
780 if ((chan->flags & (IEEE80211_CHAN_NO_IR | IEEE80211_CHAN_RADAR)) ||
781 !scan_req->n_ssids) {
782 *next_delay = IEEE80211_PASSIVE_CHANNEL_TIME;
783 local->next_scan_state = SCAN_DECISION;
784 return;
785 }
786
787 /* active scan, send probes */
788 *next_delay = IEEE80211_PROBE_DELAY;
789 local->next_scan_state = SCAN_SEND_PROBE;
790 }
791
792 static void ieee80211_scan_state_suspend(struct ieee80211_local *local,
793 unsigned long *next_delay)
794 {
795 /* switch back to the operating channel */
796 local->scan_chandef.chan = NULL;
797 ieee80211_hw_config(local, IEEE80211_CONF_CHANGE_CHANNEL);
798
799 /* disable PS */
800 ieee80211_offchannel_return(local);
801
802 *next_delay = HZ / 5;
803 /* afterwards, resume scan & go to next channel */
804 local->next_scan_state = SCAN_RESUME;
805 }
806
807 static void ieee80211_scan_state_resume(struct ieee80211_local *local,
808 unsigned long *next_delay)
809 {
810 ieee80211_offchannel_stop_vifs(local);
811
812 if (local->ops->flush) {
813 ieee80211_flush_queues(local, NULL, false);
814 *next_delay = 0;
815 } else
816 *next_delay = HZ / 10;
817
818 /* remember when we left the operating channel */
819 local->leave_oper_channel_time = jiffies;
820
821 /* advance to the next channel to be scanned */
822 local->next_scan_state = SCAN_SET_CHANNEL;
823 }
824
825 void ieee80211_scan_work(struct work_struct *work)
826 {
827 struct ieee80211_local *local =
828 container_of(work, struct ieee80211_local, scan_work.work);
829 struct ieee80211_sub_if_data *sdata;
830 struct cfg80211_scan_request *scan_req;
831 unsigned long next_delay = 0;
832 bool aborted;
833
834 mutex_lock(&local->mtx);
835
836 if (!ieee80211_can_run_worker(local)) {
837 aborted = true;
838 goto out_complete;
839 }
840
841 sdata = rcu_dereference_protected(local->scan_sdata,
842 lockdep_is_held(&local->mtx));
843 scan_req = rcu_dereference_protected(local->scan_req,
844 lockdep_is_held(&local->mtx));
845
846 /* When scanning on-channel, the first-callback means completed. */
847 if (test_bit(SCAN_ONCHANNEL_SCANNING, &local->scanning)) {
848 aborted = test_and_clear_bit(SCAN_ABORTED, &local->scanning);
849 goto out_complete;
850 }
851
852 if (test_and_clear_bit(SCAN_COMPLETED, &local->scanning)) {
853 aborted = test_and_clear_bit(SCAN_ABORTED, &local->scanning);
854 goto out_complete;
855 }
856
857 if (!sdata || !scan_req)
858 goto out;
859
860 if (!local->scanning) {
861 int rc;
862
863 RCU_INIT_POINTER(local->scan_req, NULL);
864 RCU_INIT_POINTER(local->scan_sdata, NULL);
865
866 rc = __ieee80211_start_scan(sdata, scan_req);
867 if (rc) {
868 /* need to complete scan in cfg80211 */
869 rcu_assign_pointer(local->scan_req, scan_req);
870 aborted = true;
871 goto out_complete;
872 } else
873 goto out;
874 }
875
876 /*
877 * as long as no delay is required advance immediately
878 * without scheduling a new work
879 */
880 do {
881 if (!ieee80211_sdata_running(sdata)) {
882 aborted = true;
883 goto out_complete;
884 }
885
886 switch (local->next_scan_state) {
887 case SCAN_DECISION:
888 /* if no more bands/channels left, complete scan */
889 if (local->scan_channel_idx >= scan_req->n_channels) {
890 aborted = false;
891 goto out_complete;
892 }
893 ieee80211_scan_state_decision(local, &next_delay);
894 break;
895 case SCAN_SET_CHANNEL:
896 ieee80211_scan_state_set_channel(local, &next_delay);
897 break;
898 case SCAN_SEND_PROBE:
899 ieee80211_scan_state_send_probe(local, &next_delay);
900 break;
901 case SCAN_SUSPEND:
902 ieee80211_scan_state_suspend(local, &next_delay);
903 break;
904 case SCAN_RESUME:
905 ieee80211_scan_state_resume(local, &next_delay);
906 break;
907 case SCAN_ABORT:
908 aborted = true;
909 goto out_complete;
910 }
911 } while (next_delay == 0);
912
913 ieee80211_queue_delayed_work(&local->hw, &local->scan_work, next_delay);
914 goto out;
915
916 out_complete:
917 __ieee80211_scan_completed(&local->hw, aborted);
918 out:
919 mutex_unlock(&local->mtx);
920 }
921
922 int ieee80211_request_scan(struct ieee80211_sub_if_data *sdata,
923 struct cfg80211_scan_request *req)
924 {
925 int res;
926
927 mutex_lock(&sdata->local->mtx);
928 res = __ieee80211_start_scan(sdata, req);
929 mutex_unlock(&sdata->local->mtx);
930
931 return res;
932 }
933
934 int ieee80211_request_ibss_scan(struct ieee80211_sub_if_data *sdata,
935 const u8 *ssid, u8 ssid_len,
936 struct ieee80211_channel **channels,
937 unsigned int n_channels,
938 enum nl80211_bss_scan_width scan_width)
939 {
940 struct ieee80211_local *local = sdata->local;
941 int ret = -EBUSY, i, n_ch = 0;
942 enum ieee80211_band band;
943
944 mutex_lock(&local->mtx);
945
946 /* busy scanning */
947 if (local->scan_req)
948 goto unlock;
949
950 /* fill internal scan request */
951 if (!channels) {
952 int max_n;
953
954 for (band = 0; band < IEEE80211_NUM_BANDS; band++) {
955 if (!local->hw.wiphy->bands[band])
956 continue;
957
958 max_n = local->hw.wiphy->bands[band]->n_channels;
959 for (i = 0; i < max_n; i++) {
960 struct ieee80211_channel *tmp_ch =
961 &local->hw.wiphy->bands[band]->channels[i];
962
963 if (tmp_ch->flags & (IEEE80211_CHAN_NO_IR |
964 IEEE80211_CHAN_DISABLED))
965 continue;
966
967 local->int_scan_req->channels[n_ch] = tmp_ch;
968 n_ch++;
969 }
970 }
971
972 if (WARN_ON_ONCE(n_ch == 0))
973 goto unlock;
974
975 local->int_scan_req->n_channels = n_ch;
976 } else {
977 for (i = 0; i < n_channels; i++) {
978 if (channels[i]->flags & (IEEE80211_CHAN_NO_IR |
979 IEEE80211_CHAN_DISABLED))
980 continue;
981
982 local->int_scan_req->channels[n_ch] = channels[i];
983 n_ch++;
984 }
985
986 if (WARN_ON_ONCE(n_ch == 0))
987 goto unlock;
988
989 local->int_scan_req->n_channels = n_ch;
990 }
991
992 local->int_scan_req->ssids = &local->scan_ssid;
993 local->int_scan_req->n_ssids = 1;
994 local->int_scan_req->scan_width = scan_width;
995 memcpy(local->int_scan_req->ssids[0].ssid, ssid, IEEE80211_MAX_SSID_LEN);
996 local->int_scan_req->ssids[0].ssid_len = ssid_len;
997
998 ret = __ieee80211_start_scan(sdata, sdata->local->int_scan_req);
999 unlock:
1000 mutex_unlock(&local->mtx);
1001 return ret;
1002 }
1003
1004 /*
1005 * Only call this function when a scan can't be queued -- under RTNL.
1006 */
1007 void ieee80211_scan_cancel(struct ieee80211_local *local)
1008 {
1009 /*
1010 * We are canceling software scan, or deferred scan that was not
1011 * yet really started (see __ieee80211_start_scan ).
1012 *
1013 * Regarding hardware scan:
1014 * - we can not call __ieee80211_scan_completed() as when
1015 * SCAN_HW_SCANNING bit is set this function change
1016 * local->hw_scan_req to operate on 5G band, what race with
1017 * driver which can use local->hw_scan_req
1018 *
1019 * - we can not cancel scan_work since driver can schedule it
1020 * by ieee80211_scan_completed(..., true) to finish scan
1021 *
1022 * Hence we only call the cancel_hw_scan() callback, but the low-level
1023 * driver is still responsible for calling ieee80211_scan_completed()
1024 * after the scan was completed/aborted.
1025 */
1026
1027 mutex_lock(&local->mtx);
1028 if (!local->scan_req)
1029 goto out;
1030
1031 /*
1032 * We have a scan running and the driver already reported completion,
1033 * but the worker hasn't run yet or is stuck on the mutex - mark it as
1034 * cancelled.
1035 */
1036 if (test_bit(SCAN_HW_SCANNING, &local->scanning) &&
1037 test_bit(SCAN_COMPLETED, &local->scanning)) {
1038 set_bit(SCAN_HW_CANCELLED, &local->scanning);
1039 goto out;
1040 }
1041
1042 if (test_bit(SCAN_HW_SCANNING, &local->scanning)) {
1043 /*
1044 * Make sure that __ieee80211_scan_completed doesn't trigger a
1045 * scan on another band.
1046 */
1047 set_bit(SCAN_HW_CANCELLED, &local->scanning);
1048 if (local->ops->cancel_hw_scan)
1049 drv_cancel_hw_scan(local,
1050 rcu_dereference_protected(local->scan_sdata,
1051 lockdep_is_held(&local->mtx)));
1052 goto out;
1053 }
1054
1055 /*
1056 * If the work is currently running, it must be blocked on
1057 * the mutex, but we'll set scan_sdata = NULL and it'll
1058 * simply exit once it acquires the mutex.
1059 */
1060 cancel_delayed_work(&local->scan_work);
1061 /* and clean up */
1062 __ieee80211_scan_completed(&local->hw, true);
1063 out:
1064 mutex_unlock(&local->mtx);
1065 }
1066
1067 int __ieee80211_request_sched_scan_start(struct ieee80211_sub_if_data *sdata,
1068 struct cfg80211_sched_scan_request *req)
1069 {
1070 struct ieee80211_local *local = sdata->local;
1071 struct ieee80211_scan_ies sched_scan_ies = {};
1072 struct cfg80211_chan_def chandef;
1073 int ret, i, iebufsz, num_bands = 0;
1074 u32 rate_masks[IEEE80211_NUM_BANDS] = {};
1075 u8 bands_used = 0;
1076 u8 *ie;
1077 size_t len;
1078
1079 iebufsz = local->scan_ies_len + req->ie_len;
1080
1081 lockdep_assert_held(&local->mtx);
1082
1083 if (!local->ops->sched_scan_start)
1084 return -ENOTSUPP;
1085
1086 for (i = 0; i < IEEE80211_NUM_BANDS; i++) {
1087 if (local->hw.wiphy->bands[i]) {
1088 bands_used |= BIT(i);
1089 rate_masks[i] = (u32) -1;
1090 num_bands++;
1091 }
1092 }
1093
1094 ie = kzalloc(num_bands * iebufsz, GFP_KERNEL);
1095 if (!ie) {
1096 ret = -ENOMEM;
1097 goto out;
1098 }
1099
1100 ieee80211_prepare_scan_chandef(&chandef, req->scan_width);
1101
1102 len = ieee80211_build_preq_ies(local, ie, num_bands * iebufsz,
1103 &sched_scan_ies, req->ie,
1104 req->ie_len, bands_used,
1105 rate_masks, &chandef);
1106
1107 ret = drv_sched_scan_start(local, sdata, req, &sched_scan_ies);
1108 if (ret == 0) {
1109 rcu_assign_pointer(local->sched_scan_sdata, sdata);
1110 rcu_assign_pointer(local->sched_scan_req, req);
1111 }
1112
1113 kfree(ie);
1114
1115 out:
1116 if (ret) {
1117 /* Clean in case of failure after HW restart or upon resume. */
1118 RCU_INIT_POINTER(local->sched_scan_sdata, NULL);
1119 RCU_INIT_POINTER(local->sched_scan_req, NULL);
1120 }
1121
1122 return ret;
1123 }
1124
1125 int ieee80211_request_sched_scan_start(struct ieee80211_sub_if_data *sdata,
1126 struct cfg80211_sched_scan_request *req)
1127 {
1128 struct ieee80211_local *local = sdata->local;
1129 int ret;
1130
1131 mutex_lock(&local->mtx);
1132
1133 if (rcu_access_pointer(local->sched_scan_sdata)) {
1134 mutex_unlock(&local->mtx);
1135 return -EBUSY;
1136 }
1137
1138 ret = __ieee80211_request_sched_scan_start(sdata, req);
1139
1140 mutex_unlock(&local->mtx);
1141 return ret;
1142 }
1143
1144 int ieee80211_request_sched_scan_stop(struct ieee80211_local *local)
1145 {
1146 struct ieee80211_sub_if_data *sched_scan_sdata;
1147 int ret = -ENOENT;
1148
1149 mutex_lock(&local->mtx);
1150
1151 if (!local->ops->sched_scan_stop) {
1152 ret = -ENOTSUPP;
1153 goto out;
1154 }
1155
1156 /* We don't want to restart sched scan anymore. */
1157 RCU_INIT_POINTER(local->sched_scan_req, NULL);
1158
1159 sched_scan_sdata = rcu_dereference_protected(local->sched_scan_sdata,
1160 lockdep_is_held(&local->mtx));
1161 if (sched_scan_sdata) {
1162 ret = drv_sched_scan_stop(local, sched_scan_sdata);
1163 if (!ret)
1164 RCU_INIT_POINTER(local->sched_scan_sdata, NULL);
1165 }
1166 out:
1167 mutex_unlock(&local->mtx);
1168
1169 return ret;
1170 }
1171
1172 void ieee80211_sched_scan_results(struct ieee80211_hw *hw)
1173 {
1174 struct ieee80211_local *local = hw_to_local(hw);
1175
1176 trace_api_sched_scan_results(local);
1177
1178 cfg80211_sched_scan_results(hw->wiphy);
1179 }
1180 EXPORT_SYMBOL(ieee80211_sched_scan_results);
1181
1182 void ieee80211_sched_scan_end(struct ieee80211_local *local)
1183 {
1184 mutex_lock(&local->mtx);
1185
1186 if (!rcu_access_pointer(local->sched_scan_sdata)) {
1187 mutex_unlock(&local->mtx);
1188 return;
1189 }
1190
1191 RCU_INIT_POINTER(local->sched_scan_sdata, NULL);
1192
1193 /* If sched scan was aborted by the driver. */
1194 RCU_INIT_POINTER(local->sched_scan_req, NULL);
1195
1196 mutex_unlock(&local->mtx);
1197
1198 cfg80211_sched_scan_stopped(local->hw.wiphy);
1199 }
1200
1201 void ieee80211_sched_scan_stopped_work(struct work_struct *work)
1202 {
1203 struct ieee80211_local *local =
1204 container_of(work, struct ieee80211_local,
1205 sched_scan_stopped_work);
1206
1207 ieee80211_sched_scan_end(local);
1208 }
1209
1210 void ieee80211_sched_scan_stopped(struct ieee80211_hw *hw)
1211 {
1212 struct ieee80211_local *local = hw_to_local(hw);
1213
1214 trace_api_sched_scan_stopped(local);
1215
1216 schedule_work(&local->sched_scan_stopped_work);
1217 }
1218 EXPORT_SYMBOL(ieee80211_sched_scan_stopped);
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