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 *
10 * This program is free software; you can redistribute it and/or modify
11 * it under the terms of the GNU General Public License version 2 as
12 * published by the Free Software Foundation.
13 */
14
15 #include <linux/if_arp.h>
16 #include <linux/etherdevice.h>
17 #include <linux/rtnetlink.h>
18 #include <linux/pm_qos.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 / 8)
31
32 struct ieee80211_bss *
ieee80211_rx_bss_get(struct ieee80211_local * local,u8 * bssid,int freq,u8 * ssid,u8 ssid_len)33 ieee80211_rx_bss_get(struct ieee80211_local *local, u8 *bssid, int freq,
34 u8 *ssid, u8 ssid_len)
35 {
36 struct cfg80211_bss *cbss;
37
38 cbss = cfg80211_get_bss(local->hw.wiphy,
39 ieee80211_get_channel(local->hw.wiphy, freq),
40 bssid, ssid, ssid_len, 0, 0);
41 if (!cbss)
42 return NULL;
43 return (void *)cbss->priv;
44 }
45
ieee80211_rx_bss_free(struct cfg80211_bss * cbss)46 static void ieee80211_rx_bss_free(struct cfg80211_bss *cbss)
47 {
48 struct ieee80211_bss *bss = (void *)cbss->priv;
49
50 kfree(bss_mesh_id(bss));
51 kfree(bss_mesh_cfg(bss));
52 }
53
ieee80211_rx_bss_put(struct ieee80211_local * local,struct ieee80211_bss * bss)54 void ieee80211_rx_bss_put(struct ieee80211_local *local,
55 struct ieee80211_bss *bss)
56 {
57 if (!bss)
58 return;
59 cfg80211_put_bss(container_of((void *)bss, struct cfg80211_bss, priv));
60 }
61
is_uapsd_supported(struct ieee802_11_elems * elems)62 static bool is_uapsd_supported(struct ieee802_11_elems *elems)
63 {
64 u8 qos_info;
65
66 if (elems->wmm_info && elems->wmm_info_len == 7
67 && elems->wmm_info[5] == 1)
68 qos_info = elems->wmm_info[6];
69 else if (elems->wmm_param && elems->wmm_param_len == 24
70 && elems->wmm_param[5] == 1)
71 qos_info = elems->wmm_param[6];
72 else
73 /* no valid wmm information or parameter element found */
74 return false;
75
76 return qos_info & IEEE80211_WMM_IE_AP_QOSINFO_UAPSD;
77 }
78
79 struct ieee80211_bss *
ieee80211_bss_info_update(struct ieee80211_local * local,struct ieee80211_rx_status * rx_status,struct ieee80211_mgmt * mgmt,size_t len,struct ieee802_11_elems * elems,struct ieee80211_channel * channel,bool beacon)80 ieee80211_bss_info_update(struct ieee80211_local *local,
81 struct ieee80211_rx_status *rx_status,
82 struct ieee80211_mgmt *mgmt,
83 size_t len,
84 struct ieee802_11_elems *elems,
85 struct ieee80211_channel *channel,
86 bool beacon)
87 {
88 struct cfg80211_bss *cbss;
89 struct ieee80211_bss *bss;
90 int clen, srlen;
91 s32 signal = 0;
92
93 if (local->hw.flags & IEEE80211_HW_SIGNAL_DBM)
94 signal = rx_status->signal * 100;
95 else if (local->hw.flags & IEEE80211_HW_SIGNAL_UNSPEC)
96 signal = (rx_status->signal * 100) / local->hw.max_signal;
97
98 cbss = cfg80211_inform_bss_frame(local->hw.wiphy, channel,
99 mgmt, len, signal, GFP_ATOMIC);
100
101 if (!cbss)
102 return NULL;
103
104 cbss->free_priv = ieee80211_rx_bss_free;
105 bss = (void *)cbss->priv;
106
107 if (elems->parse_error) {
108 if (beacon)
109 bss->corrupt_data |= IEEE80211_BSS_CORRUPT_BEACON;
110 else
111 bss->corrupt_data |= IEEE80211_BSS_CORRUPT_PROBE_RESP;
112 } else {
113 if (beacon)
114 bss->corrupt_data &= ~IEEE80211_BSS_CORRUPT_BEACON;
115 else
116 bss->corrupt_data &= ~IEEE80211_BSS_CORRUPT_PROBE_RESP;
117 }
118
119 /* save the ERP value so that it is available at association time */
120 if (elems->erp_info && elems->erp_info_len >= 1 &&
121 (!elems->parse_error ||
122 !(bss->valid_data & IEEE80211_BSS_VALID_ERP))) {
123 bss->erp_value = elems->erp_info[0];
124 bss->has_erp_value = true;
125 if (!elems->parse_error)
126 bss->valid_data |= IEEE80211_BSS_VALID_ERP;
127 }
128
129 if (elems->tim && (!elems->parse_error ||
130 !(bss->valid_data & IEEE80211_BSS_VALID_DTIM))) {
131 struct ieee80211_tim_ie *tim_ie =
132 (struct ieee80211_tim_ie *)elems->tim;
133 bss->dtim_period = tim_ie->dtim_period;
134 if (!elems->parse_error)
135 bss->valid_data |= IEEE80211_BSS_VALID_DTIM;
136 }
137
138 /* If the beacon had no TIM IE, or it was invalid, use 1 */
139 if (beacon && !bss->dtim_period)
140 bss->dtim_period = 1;
141
142 /* replace old supported rates if we get new values */
143 if (!elems->parse_error ||
144 !(bss->valid_data & IEEE80211_BSS_VALID_RATES)) {
145 srlen = 0;
146 if (elems->supp_rates) {
147 clen = IEEE80211_MAX_SUPP_RATES;
148 if (clen > elems->supp_rates_len)
149 clen = elems->supp_rates_len;
150 memcpy(bss->supp_rates, elems->supp_rates, clen);
151 srlen += clen;
152 }
153 if (elems->ext_supp_rates) {
154 clen = IEEE80211_MAX_SUPP_RATES - srlen;
155 if (clen > elems->ext_supp_rates_len)
156 clen = elems->ext_supp_rates_len;
157 memcpy(bss->supp_rates + srlen, elems->ext_supp_rates,
158 clen);
159 srlen += clen;
160 }
161 if (srlen) {
162 bss->supp_rates_len = srlen;
163 if (!elems->parse_error)
164 bss->valid_data |= IEEE80211_BSS_VALID_RATES;
165 }
166 }
167
168 if (!elems->parse_error ||
169 !(bss->valid_data & IEEE80211_BSS_VALID_WMM)) {
170 bss->wmm_used = elems->wmm_param || elems->wmm_info;
171 bss->uapsd_supported = is_uapsd_supported(elems);
172 if (!elems->parse_error)
173 bss->valid_data |= IEEE80211_BSS_VALID_WMM;
174 }
175
176 if (!beacon)
177 bss->last_probe_resp = jiffies;
178
179 return bss;
180 }
181
182 ieee80211_rx_result
ieee80211_scan_rx(struct ieee80211_sub_if_data * sdata,struct sk_buff * skb)183 ieee80211_scan_rx(struct ieee80211_sub_if_data *sdata, struct sk_buff *skb)
184 {
185 struct ieee80211_rx_status *rx_status = IEEE80211_SKB_RXCB(skb);
186 struct ieee80211_mgmt *mgmt;
187 struct ieee80211_bss *bss;
188 u8 *elements;
189 struct ieee80211_channel *channel;
190 size_t baselen;
191 int freq;
192 __le16 fc;
193 bool presp, beacon = false;
194 struct ieee802_11_elems elems;
195
196 if (skb->len < 2)
197 return RX_DROP_UNUSABLE;
198
199 mgmt = (struct ieee80211_mgmt *) skb->data;
200 fc = mgmt->frame_control;
201
202 if (ieee80211_is_ctl(fc))
203 return RX_CONTINUE;
204
205 if (skb->len < 24)
206 return RX_CONTINUE;
207
208 presp = ieee80211_is_probe_resp(fc);
209 if (presp) {
210 /* ignore ProbeResp to foreign address */
211 if (compare_ether_addr(mgmt->da, sdata->vif.addr))
212 return RX_DROP_MONITOR;
213
214 presp = true;
215 elements = mgmt->u.probe_resp.variable;
216 baselen = offsetof(struct ieee80211_mgmt, u.probe_resp.variable);
217 } else {
218 beacon = ieee80211_is_beacon(fc);
219 baselen = offsetof(struct ieee80211_mgmt, u.beacon.variable);
220 elements = mgmt->u.beacon.variable;
221 }
222
223 if (!presp && !beacon)
224 return RX_CONTINUE;
225
226 if (baselen > skb->len)
227 return RX_DROP_MONITOR;
228
229 ieee802_11_parse_elems(elements, skb->len - baselen, &elems);
230
231 if (elems.ds_params && elems.ds_params_len == 1)
232 freq = ieee80211_channel_to_frequency(elems.ds_params[0],
233 rx_status->band);
234 else
235 freq = rx_status->freq;
236
237 channel = ieee80211_get_channel(sdata->local->hw.wiphy, freq);
238
239 if (!channel || channel->flags & IEEE80211_CHAN_DISABLED)
240 return RX_DROP_MONITOR;
241
242 bss = ieee80211_bss_info_update(sdata->local, rx_status,
243 mgmt, skb->len, &elems,
244 channel, beacon);
245 if (bss)
246 ieee80211_rx_bss_put(sdata->local, bss);
247
248 if (channel == sdata->local->oper_channel)
249 return RX_CONTINUE;
250
251 dev_kfree_skb(skb);
252 return RX_QUEUED;
253 }
254
255 /* return false if no more work */
ieee80211_prep_hw_scan(struct ieee80211_local * local)256 static bool ieee80211_prep_hw_scan(struct ieee80211_local *local)
257 {
258 struct cfg80211_scan_request *req = local->scan_req;
259 enum ieee80211_band band;
260 int i, ielen, n_chans;
261
262 if (test_bit(SCAN_HW_CANCELLED, &local->scanning))
263 return false;
264
265 do {
266 if (local->hw_scan_band == IEEE80211_NUM_BANDS)
267 return false;
268
269 band = local->hw_scan_band;
270 n_chans = 0;
271 for (i = 0; i < req->n_channels; i++) {
272 if (req->channels[i]->band == band) {
273 local->hw_scan_req->channels[n_chans] =
274 req->channels[i];
275 n_chans++;
276 }
277 }
278
279 local->hw_scan_band++;
280 } while (!n_chans);
281
282 local->hw_scan_req->n_channels = n_chans;
283
284 ielen = ieee80211_build_preq_ies(local, (u8 *)local->hw_scan_req->ie,
285 req->ie, req->ie_len, band,
286 req->rates[band], 0);
287 local->hw_scan_req->ie_len = ielen;
288 local->hw_scan_req->no_cck = req->no_cck;
289
290 return true;
291 }
292
__ieee80211_scan_completed(struct ieee80211_hw * hw,bool aborted,bool was_hw_scan)293 static void __ieee80211_scan_completed(struct ieee80211_hw *hw, bool aborted,
294 bool was_hw_scan)
295 {
296 struct ieee80211_local *local = hw_to_local(hw);
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 (was_hw_scan && !aborted && ieee80211_prep_hw_scan(local)) {
313 int rc = drv_hw_scan(local, local->scan_sdata, local->hw_scan_req);
314 if (rc == 0)
315 return;
316 }
317
318 kfree(local->hw_scan_req);
319 local->hw_scan_req = NULL;
320
321 if (local->scan_req != local->int_scan_req)
322 cfg80211_scan_done(local->scan_req, aborted);
323 local->scan_req = NULL;
324 local->scan_sdata = NULL;
325
326 local->scanning = 0;
327 local->scan_channel = NULL;
328
329 /* Set power back to normal operating levels. */
330 ieee80211_hw_config(local, 0);
331
332 if (!was_hw_scan) {
333 ieee80211_configure_filter(local);
334 drv_sw_scan_complete(local);
335 ieee80211_offchannel_return(local);
336 }
337
338 ieee80211_recalc_idle(local);
339
340 ieee80211_mlme_notify_scan_completed(local);
341 ieee80211_ibss_notify_scan_completed(local);
342 ieee80211_mesh_notify_scan_completed(local);
343 ieee80211_queue_work(&local->hw, &local->work_work);
344 }
345
ieee80211_scan_completed(struct ieee80211_hw * hw,bool aborted)346 void ieee80211_scan_completed(struct ieee80211_hw *hw, bool aborted)
347 {
348 struct ieee80211_local *local = hw_to_local(hw);
349
350 trace_api_scan_completed(local, aborted);
351
352 set_bit(SCAN_COMPLETED, &local->scanning);
353 if (aborted)
354 set_bit(SCAN_ABORTED, &local->scanning);
355 ieee80211_queue_delayed_work(&local->hw, &local->scan_work, 0);
356 }
357 EXPORT_SYMBOL(ieee80211_scan_completed);
358
ieee80211_start_sw_scan(struct ieee80211_local * local)359 static int ieee80211_start_sw_scan(struct ieee80211_local *local)
360 {
361 /*
362 * Hardware/driver doesn't support hw_scan, so use software
363 * scanning instead. First send a nullfunc frame with power save
364 * bit on so that AP will buffer the frames for us while we are not
365 * listening, then send probe requests to each channel and wait for
366 * the responses. After all channels are scanned, tune back to the
367 * original channel and send a nullfunc frame with power save bit
368 * off to trigger the AP to send us all the buffered frames.
369 *
370 * Note that while local->sw_scanning is true everything else but
371 * nullfunc frames and probe requests will be dropped in
372 * ieee80211_tx_h_check_assoc().
373 */
374 drv_sw_scan_start(local);
375
376 local->leave_oper_channel_time = jiffies;
377 local->next_scan_state = SCAN_DECISION;
378 local->scan_channel_idx = 0;
379
380 ieee80211_offchannel_stop_vifs(local);
381
382 ieee80211_configure_filter(local);
383
384 /* We need to set power level at maximum rate for scanning. */
385 ieee80211_hw_config(local, 0);
386
387 ieee80211_queue_delayed_work(&local->hw,
388 &local->scan_work, 0);
389
390 return 0;
391 }
392
393
__ieee80211_start_scan(struct ieee80211_sub_if_data * sdata,struct cfg80211_scan_request * req)394 static int __ieee80211_start_scan(struct ieee80211_sub_if_data *sdata,
395 struct cfg80211_scan_request *req)
396 {
397 struct ieee80211_local *local = sdata->local;
398 int rc;
399
400 lockdep_assert_held(&local->mtx);
401
402 if (local->scan_req)
403 return -EBUSY;
404
405 if (!list_empty(&local->work_list)) {
406 /* wait for the work to finish/time out */
407 local->scan_req = req;
408 local->scan_sdata = sdata;
409 return 0;
410 }
411
412 if (local->ops->hw_scan) {
413 u8 *ies;
414
415 local->hw_scan_req = kmalloc(
416 sizeof(*local->hw_scan_req) +
417 req->n_channels * sizeof(req->channels[0]) +
418 2 + IEEE80211_MAX_SSID_LEN + local->scan_ies_len +
419 req->ie_len, GFP_KERNEL);
420 if (!local->hw_scan_req)
421 return -ENOMEM;
422
423 local->hw_scan_req->ssids = req->ssids;
424 local->hw_scan_req->n_ssids = req->n_ssids;
425 ies = (u8 *)local->hw_scan_req +
426 sizeof(*local->hw_scan_req) +
427 req->n_channels * sizeof(req->channels[0]);
428 local->hw_scan_req->ie = ies;
429
430 local->hw_scan_band = 0;
431
432 /*
433 * After allocating local->hw_scan_req, we must
434 * go through until ieee80211_prep_hw_scan(), so
435 * anything that might be changed here and leave
436 * this function early must not go after this
437 * allocation.
438 */
439 }
440
441 local->scan_req = req;
442 local->scan_sdata = sdata;
443
444 if (local->ops->hw_scan)
445 __set_bit(SCAN_HW_SCANNING, &local->scanning);
446 else
447 __set_bit(SCAN_SW_SCANNING, &local->scanning);
448
449 ieee80211_recalc_idle(local);
450
451 if (local->ops->hw_scan) {
452 WARN_ON(!ieee80211_prep_hw_scan(local));
453 rc = drv_hw_scan(local, sdata, local->hw_scan_req);
454 } else
455 rc = ieee80211_start_sw_scan(local);
456
457 if (rc) {
458 kfree(local->hw_scan_req);
459 local->hw_scan_req = NULL;
460 local->scanning = 0;
461
462 ieee80211_recalc_idle(local);
463
464 local->scan_req = NULL;
465 local->scan_sdata = NULL;
466 }
467
468 return rc;
469 }
470
471 static unsigned long
ieee80211_scan_get_channel_time(struct ieee80211_channel * chan)472 ieee80211_scan_get_channel_time(struct ieee80211_channel *chan)
473 {
474 /*
475 * TODO: channel switching also consumes quite some time,
476 * add that delay as well to get a better estimation
477 */
478 if (chan->flags & IEEE80211_CHAN_PASSIVE_SCAN)
479 return IEEE80211_PASSIVE_CHANNEL_TIME;
480 return IEEE80211_PROBE_DELAY + IEEE80211_CHANNEL_TIME;
481 }
482
ieee80211_scan_state_decision(struct ieee80211_local * local,unsigned long * next_delay)483 static void ieee80211_scan_state_decision(struct ieee80211_local *local,
484 unsigned long *next_delay)
485 {
486 bool associated = false;
487 bool tx_empty = true;
488 bool bad_latency;
489 bool listen_int_exceeded;
490 unsigned long min_beacon_int = 0;
491 struct ieee80211_sub_if_data *sdata;
492 struct ieee80211_channel *next_chan;
493
494 /*
495 * check if at least one STA interface is associated,
496 * check if at least one STA interface has pending tx frames
497 * and grab the lowest used beacon interval
498 */
499 mutex_lock(&local->iflist_mtx);
500 list_for_each_entry(sdata, &local->interfaces, list) {
501 if (!ieee80211_sdata_running(sdata))
502 continue;
503
504 if (sdata->vif.type == NL80211_IFTYPE_STATION) {
505 if (sdata->u.mgd.associated) {
506 associated = true;
507
508 if (sdata->vif.bss_conf.beacon_int <
509 min_beacon_int || min_beacon_int == 0)
510 min_beacon_int =
511 sdata->vif.bss_conf.beacon_int;
512
513 if (!qdisc_all_tx_empty(sdata->dev)) {
514 tx_empty = false;
515 break;
516 }
517 }
518 }
519 }
520 mutex_unlock(&local->iflist_mtx);
521
522 next_chan = local->scan_req->channels[local->scan_channel_idx];
523
524 /*
525 * we're currently scanning a different channel, let's
526 * see if we can scan another channel without interfering
527 * with the current traffic situation.
528 *
529 * Since we don't know if the AP has pending frames for us
530 * we can only check for our tx queues and use the current
531 * pm_qos requirements for rx. Hence, if no tx traffic occurs
532 * at all we will scan as many channels in a row as the pm_qos
533 * latency allows us to. Additionally we also check for the
534 * currently negotiated listen interval to prevent losing
535 * frames unnecessarily.
536 *
537 * Otherwise switch back to the operating channel.
538 */
539
540 bad_latency = time_after(jiffies +
541 ieee80211_scan_get_channel_time(next_chan),
542 local->leave_oper_channel_time +
543 usecs_to_jiffies(pm_qos_request(PM_QOS_NETWORK_LATENCY)));
544
545 listen_int_exceeded = time_after(jiffies +
546 ieee80211_scan_get_channel_time(next_chan),
547 local->leave_oper_channel_time +
548 usecs_to_jiffies(min_beacon_int * 1024) *
549 local->hw.conf.listen_interval);
550
551 if (associated && (!tx_empty || bad_latency || listen_int_exceeded))
552 local->next_scan_state = SCAN_SUSPEND;
553 else
554 local->next_scan_state = SCAN_SET_CHANNEL;
555
556 *next_delay = 0;
557 }
558
ieee80211_scan_state_set_channel(struct ieee80211_local * local,unsigned long * next_delay)559 static void ieee80211_scan_state_set_channel(struct ieee80211_local *local,
560 unsigned long *next_delay)
561 {
562 int skip;
563 struct ieee80211_channel *chan;
564
565 skip = 0;
566 chan = local->scan_req->channels[local->scan_channel_idx];
567
568 local->scan_channel = chan;
569
570 if (ieee80211_hw_config(local, IEEE80211_CONF_CHANGE_CHANNEL))
571 skip = 1;
572
573 /* advance state machine to next channel/band */
574 local->scan_channel_idx++;
575
576 if (skip) {
577 /* if we skip this channel return to the decision state */
578 local->next_scan_state = SCAN_DECISION;
579 return;
580 }
581
582 /*
583 * Probe delay is used to update the NAV, cf. 11.1.3.2.2
584 * (which unfortunately doesn't say _why_ step a) is done,
585 * but it waits for the probe delay or until a frame is
586 * received - and the received frame would update the NAV).
587 * For now, we do not support waiting until a frame is
588 * received.
589 *
590 * In any case, it is not necessary for a passive scan.
591 */
592 if (chan->flags & IEEE80211_CHAN_PASSIVE_SCAN ||
593 !local->scan_req->n_ssids) {
594 *next_delay = IEEE80211_PASSIVE_CHANNEL_TIME;
595 local->next_scan_state = SCAN_DECISION;
596 return;
597 }
598
599 /* active scan, send probes */
600 *next_delay = IEEE80211_PROBE_DELAY;
601 local->next_scan_state = SCAN_SEND_PROBE;
602 }
603
ieee80211_scan_state_send_probe(struct ieee80211_local * local,unsigned long * next_delay)604 static void ieee80211_scan_state_send_probe(struct ieee80211_local *local,
605 unsigned long *next_delay)
606 {
607 int i;
608 struct ieee80211_sub_if_data *sdata = local->scan_sdata;
609 enum ieee80211_band band = local->hw.conf.channel->band;
610
611 for (i = 0; i < local->scan_req->n_ssids; i++)
612 ieee80211_send_probe_req(
613 sdata, NULL,
614 local->scan_req->ssids[i].ssid,
615 local->scan_req->ssids[i].ssid_len,
616 local->scan_req->ie, local->scan_req->ie_len,
617 local->scan_req->rates[band], false,
618 local->scan_req->no_cck);
619
620 /*
621 * After sending probe requests, wait for probe responses
622 * on the channel.
623 */
624 *next_delay = IEEE80211_CHANNEL_TIME;
625 local->next_scan_state = SCAN_DECISION;
626 }
627
ieee80211_scan_state_suspend(struct ieee80211_local * local,unsigned long * next_delay)628 static void ieee80211_scan_state_suspend(struct ieee80211_local *local,
629 unsigned long *next_delay)
630 {
631 /* switch back to the operating channel */
632 local->scan_channel = NULL;
633 ieee80211_hw_config(local, IEEE80211_CONF_CHANGE_CHANNEL);
634
635 /* disable PS */
636 ieee80211_offchannel_return(local);
637
638 *next_delay = HZ / 5;
639 /* afterwards, resume scan & go to next channel */
640 local->next_scan_state = SCAN_RESUME;
641 }
642
ieee80211_scan_state_resume(struct ieee80211_local * local,unsigned long * next_delay)643 static void ieee80211_scan_state_resume(struct ieee80211_local *local,
644 unsigned long *next_delay)
645 {
646 ieee80211_offchannel_stop_vifs(local);
647
648 if (local->ops->flush) {
649 drv_flush(local, false);
650 *next_delay = 0;
651 } else
652 *next_delay = HZ / 10;
653
654 /* remember when we left the operating channel */
655 local->leave_oper_channel_time = jiffies;
656
657 /* advance to the next channel to be scanned */
658 local->next_scan_state = SCAN_SET_CHANNEL;
659 }
660
ieee80211_scan_work(struct work_struct * work)661 void ieee80211_scan_work(struct work_struct *work)
662 {
663 struct ieee80211_local *local =
664 container_of(work, struct ieee80211_local, scan_work.work);
665 struct ieee80211_sub_if_data *sdata;
666 unsigned long next_delay = 0;
667 bool aborted, hw_scan;
668
669 mutex_lock(&local->mtx);
670
671 sdata = local->scan_sdata;
672
673 if (test_and_clear_bit(SCAN_COMPLETED, &local->scanning)) {
674 aborted = test_and_clear_bit(SCAN_ABORTED, &local->scanning);
675 goto out_complete;
676 }
677
678 if (!sdata || !local->scan_req)
679 goto out;
680
681 if (local->scan_req && !local->scanning) {
682 struct cfg80211_scan_request *req = local->scan_req;
683 int rc;
684
685 local->scan_req = NULL;
686 local->scan_sdata = NULL;
687
688 rc = __ieee80211_start_scan(sdata, req);
689 if (rc) {
690 /* need to complete scan in cfg80211 */
691 local->scan_req = req;
692 aborted = true;
693 goto out_complete;
694 } else
695 goto out;
696 }
697
698 /*
699 * Avoid re-scheduling when the sdata is going away.
700 */
701 if (!ieee80211_sdata_running(sdata)) {
702 aborted = true;
703 goto out_complete;
704 }
705
706 /*
707 * as long as no delay is required advance immediately
708 * without scheduling a new work
709 */
710 do {
711 if (!ieee80211_sdata_running(sdata)) {
712 aborted = true;
713 goto out_complete;
714 }
715
716 switch (local->next_scan_state) {
717 case SCAN_DECISION:
718 /* if no more bands/channels left, complete scan */
719 if (local->scan_channel_idx >= local->scan_req->n_channels) {
720 aborted = false;
721 goto out_complete;
722 }
723 ieee80211_scan_state_decision(local, &next_delay);
724 break;
725 case SCAN_SET_CHANNEL:
726 ieee80211_scan_state_set_channel(local, &next_delay);
727 break;
728 case SCAN_SEND_PROBE:
729 ieee80211_scan_state_send_probe(local, &next_delay);
730 break;
731 case SCAN_SUSPEND:
732 ieee80211_scan_state_suspend(local, &next_delay);
733 break;
734 case SCAN_RESUME:
735 ieee80211_scan_state_resume(local, &next_delay);
736 break;
737 }
738 } while (next_delay == 0);
739
740 ieee80211_queue_delayed_work(&local->hw, &local->scan_work, next_delay);
741 goto out;
742
743 out_complete:
744 hw_scan = test_bit(SCAN_HW_SCANNING, &local->scanning);
745 __ieee80211_scan_completed(&local->hw, aborted, hw_scan);
746 out:
747 mutex_unlock(&local->mtx);
748 }
749
ieee80211_request_scan(struct ieee80211_sub_if_data * sdata,struct cfg80211_scan_request * req)750 int ieee80211_request_scan(struct ieee80211_sub_if_data *sdata,
751 struct cfg80211_scan_request *req)
752 {
753 int res;
754
755 mutex_lock(&sdata->local->mtx);
756 res = __ieee80211_start_scan(sdata, req);
757 mutex_unlock(&sdata->local->mtx);
758
759 return res;
760 }
761
ieee80211_request_ibss_scan(struct ieee80211_sub_if_data * sdata,const u8 * ssid,u8 ssid_len,struct ieee80211_channel * chan)762 int ieee80211_request_ibss_scan(struct ieee80211_sub_if_data *sdata,
763 const u8 *ssid, u8 ssid_len,
764 struct ieee80211_channel *chan)
765 {
766 struct ieee80211_local *local = sdata->local;
767 int ret = -EBUSY;
768 enum ieee80211_band band;
769
770 mutex_lock(&local->mtx);
771
772 /* busy scanning */
773 if (local->scan_req)
774 goto unlock;
775
776 /* fill internal scan request */
777 if (!chan) {
778 int i, max_n;
779 int n_ch = 0;
780
781 for (band = 0; band < IEEE80211_NUM_BANDS; band++) {
782 if (!local->hw.wiphy->bands[band])
783 continue;
784
785 max_n = local->hw.wiphy->bands[band]->n_channels;
786 for (i = 0; i < max_n; i++) {
787 struct ieee80211_channel *tmp_ch =
788 &local->hw.wiphy->bands[band]->channels[i];
789
790 if (tmp_ch->flags & (IEEE80211_CHAN_NO_IBSS |
791 IEEE80211_CHAN_DISABLED))
792 continue;
793
794 local->int_scan_req->channels[n_ch] = tmp_ch;
795 n_ch++;
796 }
797 }
798
799 if (WARN_ON_ONCE(n_ch == 0))
800 goto unlock;
801
802 local->int_scan_req->n_channels = n_ch;
803 } else {
804 if (WARN_ON_ONCE(chan->flags & (IEEE80211_CHAN_NO_IBSS |
805 IEEE80211_CHAN_DISABLED)))
806 goto unlock;
807
808 local->int_scan_req->channels[0] = chan;
809 local->int_scan_req->n_channels = 1;
810 }
811
812 local->int_scan_req->ssids = &local->scan_ssid;
813 local->int_scan_req->n_ssids = 1;
814 memcpy(local->int_scan_req->ssids[0].ssid, ssid, IEEE80211_MAX_SSID_LEN);
815 local->int_scan_req->ssids[0].ssid_len = ssid_len;
816
817 ret = __ieee80211_start_scan(sdata, sdata->local->int_scan_req);
818 unlock:
819 mutex_unlock(&local->mtx);
820 return ret;
821 }
822
823 /*
824 * Only call this function when a scan can't be queued -- under RTNL.
825 */
ieee80211_scan_cancel(struct ieee80211_local * local)826 void ieee80211_scan_cancel(struct ieee80211_local *local)
827 {
828 /*
829 * We are canceling software scan, or deferred scan that was not
830 * yet really started (see __ieee80211_start_scan ).
831 *
832 * Regarding hardware scan:
833 * - we can not call __ieee80211_scan_completed() as when
834 * SCAN_HW_SCANNING bit is set this function change
835 * local->hw_scan_req to operate on 5G band, what race with
836 * driver which can use local->hw_scan_req
837 *
838 * - we can not cancel scan_work since driver can schedule it
839 * by ieee80211_scan_completed(..., true) to finish scan
840 *
841 * Hence we only call the cancel_hw_scan() callback, but the low-level
842 * driver is still responsible for calling ieee80211_scan_completed()
843 * after the scan was completed/aborted.
844 */
845
846 mutex_lock(&local->mtx);
847 if (!local->scan_req)
848 goto out;
849
850 /*
851 * We have a scan running and the driver already reported completion,
852 * but the worker hasn't run yet or is stuck on the mutex - mark it as
853 * cancelled.
854 */
855 if (test_bit(SCAN_HW_SCANNING, &local->scanning) &&
856 test_bit(SCAN_COMPLETED, &local->scanning)) {
857 set_bit(SCAN_HW_CANCELLED, &local->scanning);
858 goto out;
859 }
860
861 if (test_bit(SCAN_HW_SCANNING, &local->scanning)) {
862 /*
863 * Make sure that __ieee80211_scan_completed doesn't trigger a
864 * scan on another band.
865 */
866 set_bit(SCAN_HW_CANCELLED, &local->scanning);
867 if (local->ops->cancel_hw_scan)
868 drv_cancel_hw_scan(local, local->scan_sdata);
869 goto out;
870 }
871
872 /*
873 * If the work is currently running, it must be blocked on
874 * the mutex, but we'll set scan_sdata = NULL and it'll
875 * simply exit once it acquires the mutex.
876 */
877 cancel_delayed_work(&local->scan_work);
878 /* and clean up */
879 __ieee80211_scan_completed(&local->hw, true, false);
880 out:
881 mutex_unlock(&local->mtx);
882 }
883
ieee80211_request_sched_scan_start(struct ieee80211_sub_if_data * sdata,struct cfg80211_sched_scan_request * req)884 int ieee80211_request_sched_scan_start(struct ieee80211_sub_if_data *sdata,
885 struct cfg80211_sched_scan_request *req)
886 {
887 struct ieee80211_local *local = sdata->local;
888 int ret, i;
889
890 mutex_lock(&sdata->local->mtx);
891
892 if (local->sched_scanning) {
893 ret = -EBUSY;
894 goto out;
895 }
896
897 if (!local->ops->sched_scan_start) {
898 ret = -ENOTSUPP;
899 goto out;
900 }
901
902 for (i = 0; i < IEEE80211_NUM_BANDS; i++) {
903 local->sched_scan_ies.ie[i] = kzalloc(2 +
904 IEEE80211_MAX_SSID_LEN +
905 local->scan_ies_len +
906 req->ie_len,
907 GFP_KERNEL);
908 if (!local->sched_scan_ies.ie[i]) {
909 ret = -ENOMEM;
910 goto out_free;
911 }
912
913 local->sched_scan_ies.len[i] =
914 ieee80211_build_preq_ies(local,
915 local->sched_scan_ies.ie[i],
916 req->ie, req->ie_len, i,
917 (u32) -1, 0);
918 }
919
920 ret = drv_sched_scan_start(local, sdata, req,
921 &local->sched_scan_ies);
922 if (ret == 0) {
923 local->sched_scanning = true;
924 goto out;
925 }
926
927 out_free:
928 while (i > 0)
929 kfree(local->sched_scan_ies.ie[--i]);
930 out:
931 mutex_unlock(&sdata->local->mtx);
932 return ret;
933 }
934
ieee80211_request_sched_scan_stop(struct ieee80211_sub_if_data * sdata)935 int ieee80211_request_sched_scan_stop(struct ieee80211_sub_if_data *sdata)
936 {
937 struct ieee80211_local *local = sdata->local;
938 int ret = 0, i;
939
940 mutex_lock(&sdata->local->mtx);
941
942 if (!local->ops->sched_scan_stop) {
943 ret = -ENOTSUPP;
944 goto out;
945 }
946
947 if (local->sched_scanning) {
948 for (i = 0; i < IEEE80211_NUM_BANDS; i++)
949 kfree(local->sched_scan_ies.ie[i]);
950
951 drv_sched_scan_stop(local, sdata);
952 local->sched_scanning = false;
953 }
954 out:
955 mutex_unlock(&sdata->local->mtx);
956
957 return ret;
958 }
959
ieee80211_sched_scan_results(struct ieee80211_hw * hw)960 void ieee80211_sched_scan_results(struct ieee80211_hw *hw)
961 {
962 struct ieee80211_local *local = hw_to_local(hw);
963
964 trace_api_sched_scan_results(local);
965
966 cfg80211_sched_scan_results(hw->wiphy);
967 }
968 EXPORT_SYMBOL(ieee80211_sched_scan_results);
969
ieee80211_sched_scan_stopped_work(struct work_struct * work)970 void ieee80211_sched_scan_stopped_work(struct work_struct *work)
971 {
972 struct ieee80211_local *local =
973 container_of(work, struct ieee80211_local,
974 sched_scan_stopped_work);
975 int i;
976
977 mutex_lock(&local->mtx);
978
979 if (!local->sched_scanning) {
980 mutex_unlock(&local->mtx);
981 return;
982 }
983
984 for (i = 0; i < IEEE80211_NUM_BANDS; i++)
985 kfree(local->sched_scan_ies.ie[i]);
986
987 local->sched_scanning = false;
988
989 mutex_unlock(&local->mtx);
990
991 cfg80211_sched_scan_stopped(local->hw.wiphy);
992 }
993
ieee80211_sched_scan_stopped(struct ieee80211_hw * hw)994 void ieee80211_sched_scan_stopped(struct ieee80211_hw *hw)
995 {
996 struct ieee80211_local *local = hw_to_local(hw);
997
998 trace_api_sched_scan_stopped(local);
999
1000 ieee80211_queue_work(&local->hw, &local->sched_scan_stopped_work);
1001 }
1002 EXPORT_SYMBOL(ieee80211_sched_scan_stopped);
1003