2 * Scanning implementation
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
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.
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>
24 #include "ieee80211_i.h"
25 #include "driver-ops.h"
28 #define IEEE80211_PROBE_DELAY (HZ / 33)
29 #define IEEE80211_CHANNEL_TIME (HZ / 33)
30 #define IEEE80211_PASSIVE_CHANNEL_TIME (HZ / 9)
32 void ieee80211_rx_bss_put(struct ieee80211_local *local,
33 struct ieee80211_bss *bss)
37 cfg80211_put_bss(local->hw.wiphy,
38 container_of((void *)bss, struct cfg80211_bss, priv));
41 static bool is_uapsd_supported(struct ieee802_11_elems *elems)
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];
52 /* no valid wmm information or parameter element found */
55 return qos_info & IEEE80211_WMM_IE_AP_QOSINFO_UAPSD;
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)
65 bool beacon = ieee80211_is_beacon(mgmt->frame_control);
66 struct cfg80211_bss *cbss;
67 struct ieee80211_bss *bss;
69 struct cfg80211_inform_bss bss_meta = {};
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;
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;
83 bss_meta.chan = channel;
84 cbss = cfg80211_inform_bss_frame_data(local->hw.wiphy, &bss_meta,
85 mgmt, len, GFP_ATOMIC);
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;
92 rx_status->flag |= RX_FLAG_NO_SIGNAL_VAL;
94 bss = (void *)cbss->priv;
97 bss->device_ts_beacon = rx_status->device_timestamp;
99 bss->device_ts_presp = rx_status->device_timestamp;
101 if (elems->parse_error) {
103 bss->corrupt_data |= IEEE80211_BSS_CORRUPT_BEACON;
105 bss->corrupt_data |= IEEE80211_BSS_CORRUPT_PROBE_RESP;
108 bss->corrupt_data &= ~IEEE80211_BSS_CORRUPT_BEACON;
110 bss->corrupt_data &= ~IEEE80211_BSS_CORRUPT_PROBE_RESP;
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;
122 /* replace old supported rates if we get new values */
123 if (!elems->parse_error ||
124 !(bss->valid_data & IEEE80211_BSS_VALID_RATES)) {
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);
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,
142 bss->supp_rates_len = srlen;
143 if (!elems->parse_error)
144 bss->valid_data |= IEEE80211_BSS_VALID_RATES;
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;
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))
162 &sband->bitrates[rx_status->rate_idx];
168 void ieee80211_scan_rx(struct ieee80211_local *local, struct sk_buff *skb)
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;
175 struct ieee80211_channel *channel;
177 struct ieee802_11_elems elems;
180 (!ieee80211_is_probe_resp(mgmt->frame_control) &&
181 !ieee80211_is_beacon(mgmt->frame_control)))
184 sdata1 = rcu_dereference(local->scan_sdata);
185 sdata2 = rcu_dereference(local->sched_scan_sdata);
187 if (likely(!sdata1 && !sdata2))
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;
194 scan_req = rcu_dereference(local->scan_req);
195 sched_scan_req = rcu_dereference(local->sched_scan_req);
197 /* ignore ProbeResp to foreign address unless scanning
198 * with randomised address
201 (ether_addr_equal(mgmt->da, sdata1->vif.addr) ||
202 scan_req->flags & NL80211_SCAN_FLAG_RANDOM_ADDR)) &&
204 (ether_addr_equal(mgmt->da, sdata2->vif.addr) ||
205 sched_scan_req->flags & NL80211_SCAN_FLAG_RANDOM_ADDR)))
208 elements = mgmt->u.probe_resp.variable;
209 baselen = offsetof(struct ieee80211_mgmt, u.probe_resp.variable);
211 baselen = offsetof(struct ieee80211_mgmt, u.beacon.variable);
212 elements = mgmt->u.beacon.variable;
215 if (baselen > skb->len)
218 ieee802_11_parse_elems(elements, skb->len - baselen, false, &elems);
220 channel = ieee80211_get_channel(local->hw.wiphy, rx_status->freq);
222 if (!channel || channel->flags & IEEE80211_CHAN_DISABLED)
225 bss = ieee80211_bss_info_update(local, rx_status,
226 mgmt, skb->len, &elems,
229 ieee80211_rx_bss_put(local, bss);
233 ieee80211_prepare_scan_chandef(struct cfg80211_chan_def *chandef,
234 enum nl80211_bss_scan_width scan_width)
236 memset(chandef, 0, sizeof(*chandef));
237 switch (scan_width) {
238 case NL80211_BSS_CHAN_WIDTH_5:
239 chandef->width = NL80211_CHAN_WIDTH_5;
241 case NL80211_BSS_CHAN_WIDTH_10:
242 chandef->width = NL80211_CHAN_WIDTH_10;
245 chandef->width = NL80211_CHAN_WIDTH_20_NOHT;
250 /* return false if no more work */
251 static bool ieee80211_prep_hw_scan(struct ieee80211_local *local)
253 struct cfg80211_scan_request *req;
254 struct cfg80211_chan_def chandef;
256 int i, ielen, n_chans;
258 req = rcu_dereference_protected(local->scan_req,
259 lockdep_is_held(&local->mtx));
261 if (test_bit(SCAN_HW_CANCELLED, &local->scanning))
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);
270 n_chans = req->n_channels;
273 if (local->hw_scan_band == IEEE80211_NUM_BANDS)
278 for (i = 0; i < req->n_channels; i++) {
279 if (req->channels[i]->band !=
282 local->hw_scan_req->req.channels[n_chans] =
285 bands_used |= BIT(req->channels[i]->band);
288 local->hw_scan_band++;
292 local->hw_scan_req->req.n_channels = n_chans;
293 ieee80211_prepare_scan_chandef(&chandef, req->scan_width);
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,
310 static void __ieee80211_scan_completed(struct ieee80211_hw *hw, bool aborted)
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;
318 lockdep_assert_held(&local->mtx);
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
326 if (WARN_ON(!local->scanning && !aborted))
329 if (WARN_ON(!local->scan_req))
332 if (hw_scan && !aborted &&
333 !ieee80211_hw_check(&local->hw, SINGLE_SCAN_ON_ALL_BANDS) &&
334 ieee80211_prep_hw_scan(local)) {
337 rc = drv_hw_scan(local,
338 rcu_dereference_protected(local->scan_sdata,
339 lockdep_is_held(&local->mtx)),
346 kfree(local->hw_scan_req);
347 local->hw_scan_req = NULL;
349 scan_req = rcu_dereference_protected(local->scan_req,
350 lockdep_is_held(&local->mtx));
352 if (scan_req != local->int_scan_req)
353 cfg80211_scan_done(scan_req, aborted);
354 RCU_INIT_POINTER(local->scan_req, NULL);
356 scan_sdata = rcu_dereference_protected(local->scan_sdata,
357 lockdep_is_held(&local->mtx));
358 RCU_INIT_POINTER(local->scan_sdata, NULL);
361 local->scan_chandef.chan = NULL;
363 /* Set power back to normal operating levels. */
364 ieee80211_hw_config(local, 0);
367 ieee80211_configure_filter(local);
368 drv_sw_scan_complete(local, scan_sdata);
369 ieee80211_offchannel_return(local);
372 ieee80211_recalc_idle(local);
374 ieee80211_mlme_notify_scan_completed(local);
375 ieee80211_ibss_notify_scan_completed(local);
376 ieee80211_mesh_notify_scan_completed(local);
378 ieee80211_start_next_roc(local);
381 void ieee80211_scan_completed(struct ieee80211_hw *hw, bool aborted)
383 struct ieee80211_local *local = hw_to_local(hw);
385 trace_api_scan_completed(local, aborted);
387 set_bit(SCAN_COMPLETED, &local->scanning);
389 set_bit(SCAN_ABORTED, &local->scanning);
390 ieee80211_queue_delayed_work(&local->hw, &local->scan_work, 0);
392 EXPORT_SYMBOL(ieee80211_scan_completed);
394 static int ieee80211_start_sw_scan(struct ieee80211_local *local,
395 struct ieee80211_sub_if_data *sdata)
397 /* Software scan is not supported in multi-channel cases */
398 if (local->use_chanctx)
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.
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().
414 drv_sw_scan_start(local, sdata, local->scan_addr);
416 local->leave_oper_channel_time = jiffies;
417 local->next_scan_state = SCAN_DECISION;
418 local->scan_channel_idx = 0;
420 ieee80211_offchannel_stop_vifs(local);
422 /* ensure nullfunc is transmitted before leaving operating channel */
423 ieee80211_flush_queues(local, NULL, false);
425 ieee80211_configure_filter(local);
427 /* We need to set power level at maximum rate for scanning. */
428 ieee80211_hw_config(local, 0);
430 ieee80211_queue_delayed_work(&local->hw,
431 &local->scan_work, 0);
436 static bool ieee80211_can_scan(struct ieee80211_local *local,
437 struct ieee80211_sub_if_data *sdata)
439 if (ieee80211_is_radar_required(local))
442 if (!list_empty(&local->roc_list))
445 if (sdata->vif.type == NL80211_IFTYPE_STATION &&
446 sdata->u.mgd.flags & IEEE80211_STA_CONNECTION_POLL)
452 void ieee80211_run_deferred_scan(struct ieee80211_local *local)
454 lockdep_assert_held(&local->mtx);
456 if (!local->scan_req || local->scanning)
459 if (!ieee80211_can_scan(local,
460 rcu_dereference_protected(
462 lockdep_is_held(&local->mtx))))
465 ieee80211_queue_delayed_work(&local->hw, &local->scan_work,
466 round_jiffies_relative(0));
469 static void ieee80211_scan_state_send_probe(struct ieee80211_local *local,
470 unsigned long *next_delay)
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;
478 scan_req = rcu_dereference_protected(local->scan_req,
479 lockdep_is_held(&local->mtx));
481 tx_flags = IEEE80211_TX_INTFL_OFFCHAN_TX_OK;
482 if (scan_req->no_cck)
483 tx_flags |= IEEE80211_TX_CTL_NO_CCK_RATE;
485 sdata = rcu_dereference_protected(local->scan_sdata,
486 lockdep_is_held(&local->mtx));
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);
497 * After sending probe requests, wait for probe responses
500 *next_delay = IEEE80211_CHANNEL_TIME;
501 local->next_scan_state = SCAN_DECISION;
504 static int __ieee80211_start_scan(struct ieee80211_sub_if_data *sdata,
505 struct cfg80211_scan_request *req)
507 struct ieee80211_local *local = sdata->local;
510 lockdep_assert_held(&local->mtx);
512 if (local->scan_req || ieee80211_is_radar_required(local))
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);
522 if (local->ops->hw_scan) {
525 local->hw_scan_ies_bufsize = local->scan_ies_len + req->ie_len;
527 if (ieee80211_hw_check(&local->hw, SINGLE_SCAN_ON_ALL_BANDS)) {
529 u8 bands_counted = 0;
531 for (i = 0; i < req->n_channels; i++) {
532 if (bands_counted & BIT(req->channels[i]->band))
534 bands_counted |= BIT(req->channels[i]->band);
538 local->hw_scan_ies_bufsize *= n_bands;
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)
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;
556 local->hw_scan_band = 0;
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
567 rcu_assign_pointer(local->scan_req, req);
568 rcu_assign_pointer(local->scan_sdata, sdata);
570 if (req->flags & NL80211_SCAN_FLAG_RANDOM_ADDR)
571 get_random_mask_addr(local->scan_addr,
575 memcpy(local->scan_addr, sdata->vif.addr, ETH_ALEN);
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)) {
582 * If we are scanning only on the operating channel
583 * then we do not need to stop normal activities
585 unsigned long next_delay;
587 __set_bit(SCAN_ONCHANNEL_SCANNING, &local->scanning);
589 ieee80211_recalc_idle(local);
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);
595 ieee80211_configure_filter(local); /* accept probe-responses */
597 /* We need to ensure power level is at max for scanning. */
598 ieee80211_hw_config(local, 0);
600 if ((req->channels[0]->flags &
601 IEEE80211_CHAN_NO_IR) ||
603 next_delay = IEEE80211_PASSIVE_CHANNEL_TIME;
605 ieee80211_scan_state_send_probe(local, &next_delay);
606 next_delay = IEEE80211_CHANNEL_TIME;
609 /* Now, just wait a bit and we are all done! */
610 ieee80211_queue_delayed_work(&local->hw, &local->scan_work,
614 /* Do normal software scan */
615 __set_bit(SCAN_SW_SCANNING, &local->scanning);
618 ieee80211_recalc_idle(local);
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);
624 rc = ieee80211_start_sw_scan(local, sdata);
628 kfree(local->hw_scan_req);
629 local->hw_scan_req = NULL;
632 ieee80211_recalc_idle(local);
634 local->scan_req = NULL;
635 RCU_INIT_POINTER(local->scan_sdata, NULL);
642 ieee80211_scan_get_channel_time(struct ieee80211_channel *chan)
645 * TODO: channel switching also consumes quite some time,
646 * add that delay as well to get a better estimation
648 if (chan->flags & IEEE80211_CHAN_NO_IR)
649 return IEEE80211_PASSIVE_CHANNEL_TIME;
650 return IEEE80211_PROBE_DELAY + IEEE80211_CHANNEL_TIME;
653 static void ieee80211_scan_state_decision(struct ieee80211_local *local,
654 unsigned long *next_delay)
656 bool associated = false;
657 bool tx_empty = true;
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;
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
669 mutex_lock(&local->iflist_mtx);
670 list_for_each_entry(sdata, &local->interfaces, list) {
671 if (!ieee80211_sdata_running(sdata))
674 if (sdata->vif.type == NL80211_IFTYPE_STATION) {
675 if (sdata->u.mgd.associated) {
678 if (!qdisc_all_tx_empty(sdata->dev)) {
685 mutex_unlock(&local->iflist_mtx);
687 scan_req = rcu_dereference_protected(local->scan_req,
688 lockdep_is_held(&local->mtx));
690 next_chan = scan_req->channels[local->scan_channel_idx];
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.
697 * Keep good latency, do not stay off-channel more than 125 ms.
700 bad_latency = time_after(jiffies +
701 ieee80211_scan_get_channel_time(next_chan),
702 local->leave_oper_channel_time + HZ / 8);
704 if (associated && !tx_empty) {
705 if (scan_req->flags & NL80211_SCAN_FLAG_LOW_PRIORITY)
706 next_scan_state = SCAN_ABORT;
708 next_scan_state = SCAN_SUSPEND;
709 } else if (associated && bad_latency) {
710 next_scan_state = SCAN_SUSPEND;
712 next_scan_state = SCAN_SET_CHANNEL;
715 local->next_scan_state = next_scan_state;
720 static void ieee80211_scan_state_set_channel(struct ieee80211_local *local,
721 unsigned long *next_delay)
724 struct ieee80211_channel *chan;
725 enum nl80211_bss_scan_width oper_scan_width;
726 struct cfg80211_scan_request *scan_req;
728 scan_req = rcu_dereference_protected(local->scan_req,
729 lockdep_is_held(&local->mtx));
732 chan = scan_req->channels[local->scan_channel_idx];
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;
741 case NL80211_BSS_CHAN_WIDTH_10:
742 local->scan_chandef.width = NL80211_CHAN_WIDTH_10;
744 case NL80211_BSS_CHAN_WIDTH_20:
745 /* If scanning on oper channel, use whatever channel-type
746 * is currently in use.
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;
754 local->scan_chandef.width = NL80211_CHAN_WIDTH_20_NOHT;
758 if (ieee80211_hw_config(local, IEEE80211_CONF_CHANGE_CHANNEL))
761 /* advance state machine to next channel/band */
762 local->scan_channel_idx++;
765 /* if we skip this channel return to the decision state */
766 local->next_scan_state = SCAN_DECISION;
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
778 * In any case, it is not necessary for a passive scan.
780 if (chan->flags & IEEE80211_CHAN_NO_IR || !scan_req->n_ssids) {
781 *next_delay = IEEE80211_PASSIVE_CHANNEL_TIME;
782 local->next_scan_state = SCAN_DECISION;
786 /* active scan, send probes */
787 *next_delay = IEEE80211_PROBE_DELAY;
788 local->next_scan_state = SCAN_SEND_PROBE;
791 static void ieee80211_scan_state_suspend(struct ieee80211_local *local,
792 unsigned long *next_delay)
794 /* switch back to the operating channel */
795 local->scan_chandef.chan = NULL;
796 ieee80211_hw_config(local, IEEE80211_CONF_CHANGE_CHANNEL);
799 ieee80211_offchannel_return(local);
801 *next_delay = HZ / 5;
802 /* afterwards, resume scan & go to next channel */
803 local->next_scan_state = SCAN_RESUME;
806 static void ieee80211_scan_state_resume(struct ieee80211_local *local,
807 unsigned long *next_delay)
809 ieee80211_offchannel_stop_vifs(local);
811 if (local->ops->flush) {
812 ieee80211_flush_queues(local, NULL, false);
815 *next_delay = HZ / 10;
817 /* remember when we left the operating channel */
818 local->leave_oper_channel_time = jiffies;
820 /* advance to the next channel to be scanned */
821 local->next_scan_state = SCAN_SET_CHANNEL;
824 void ieee80211_scan_work(struct work_struct *work)
826 struct ieee80211_local *local =
827 container_of(work, struct ieee80211_local, scan_work.work);
828 struct ieee80211_sub_if_data *sdata;
829 struct cfg80211_scan_request *scan_req;
830 unsigned long next_delay = 0;
833 mutex_lock(&local->mtx);
835 if (!ieee80211_can_run_worker(local)) {
840 sdata = rcu_dereference_protected(local->scan_sdata,
841 lockdep_is_held(&local->mtx));
842 scan_req = rcu_dereference_protected(local->scan_req,
843 lockdep_is_held(&local->mtx));
845 /* When scanning on-channel, the first-callback means completed. */
846 if (test_bit(SCAN_ONCHANNEL_SCANNING, &local->scanning)) {
847 aborted = test_and_clear_bit(SCAN_ABORTED, &local->scanning);
851 if (test_and_clear_bit(SCAN_COMPLETED, &local->scanning)) {
852 aborted = test_and_clear_bit(SCAN_ABORTED, &local->scanning);
856 if (!sdata || !scan_req)
859 if (!local->scanning) {
862 RCU_INIT_POINTER(local->scan_req, NULL);
863 RCU_INIT_POINTER(local->scan_sdata, NULL);
865 rc = __ieee80211_start_scan(sdata, scan_req);
867 /* need to complete scan in cfg80211 */
868 rcu_assign_pointer(local->scan_req, scan_req);
876 * as long as no delay is required advance immediately
877 * without scheduling a new work
880 if (!ieee80211_sdata_running(sdata)) {
885 switch (local->next_scan_state) {
887 /* if no more bands/channels left, complete scan */
888 if (local->scan_channel_idx >= scan_req->n_channels) {
892 ieee80211_scan_state_decision(local, &next_delay);
894 case SCAN_SET_CHANNEL:
895 ieee80211_scan_state_set_channel(local, &next_delay);
897 case SCAN_SEND_PROBE:
898 ieee80211_scan_state_send_probe(local, &next_delay);
901 ieee80211_scan_state_suspend(local, &next_delay);
904 ieee80211_scan_state_resume(local, &next_delay);
910 } while (next_delay == 0);
912 ieee80211_queue_delayed_work(&local->hw, &local->scan_work, next_delay);
916 __ieee80211_scan_completed(&local->hw, aborted);
918 mutex_unlock(&local->mtx);
921 int ieee80211_request_scan(struct ieee80211_sub_if_data *sdata,
922 struct cfg80211_scan_request *req)
926 mutex_lock(&sdata->local->mtx);
927 res = __ieee80211_start_scan(sdata, req);
928 mutex_unlock(&sdata->local->mtx);
933 int ieee80211_request_ibss_scan(struct ieee80211_sub_if_data *sdata,
934 const u8 *ssid, u8 ssid_len,
935 struct ieee80211_channel **channels,
936 unsigned int n_channels,
937 enum nl80211_bss_scan_width scan_width)
939 struct ieee80211_local *local = sdata->local;
940 int ret = -EBUSY, i, n_ch = 0;
941 enum ieee80211_band band;
943 mutex_lock(&local->mtx);
949 /* fill internal scan request */
953 for (band = 0; band < IEEE80211_NUM_BANDS; band++) {
954 if (!local->hw.wiphy->bands[band])
957 max_n = local->hw.wiphy->bands[band]->n_channels;
958 for (i = 0; i < max_n; i++) {
959 struct ieee80211_channel *tmp_ch =
960 &local->hw.wiphy->bands[band]->channels[i];
962 if (tmp_ch->flags & (IEEE80211_CHAN_NO_IR |
963 IEEE80211_CHAN_DISABLED))
966 local->int_scan_req->channels[n_ch] = tmp_ch;
971 if (WARN_ON_ONCE(n_ch == 0))
974 local->int_scan_req->n_channels = n_ch;
976 for (i = 0; i < n_channels; i++) {
977 if (channels[i]->flags & (IEEE80211_CHAN_NO_IR |
978 IEEE80211_CHAN_DISABLED))
981 local->int_scan_req->channels[n_ch] = channels[i];
985 if (WARN_ON_ONCE(n_ch == 0))
988 local->int_scan_req->n_channels = n_ch;
991 local->int_scan_req->ssids = &local->scan_ssid;
992 local->int_scan_req->n_ssids = 1;
993 local->int_scan_req->scan_width = scan_width;
994 memcpy(local->int_scan_req->ssids[0].ssid, ssid, IEEE80211_MAX_SSID_LEN);
995 local->int_scan_req->ssids[0].ssid_len = ssid_len;
997 ret = __ieee80211_start_scan(sdata, sdata->local->int_scan_req);
999 mutex_unlock(&local->mtx);
1004 * Only call this function when a scan can't be queued -- under RTNL.
1006 void ieee80211_scan_cancel(struct ieee80211_local *local)
1009 * We are canceling software scan, or deferred scan that was not
1010 * yet really started (see __ieee80211_start_scan ).
1012 * Regarding hardware scan:
1013 * - we can not call __ieee80211_scan_completed() as when
1014 * SCAN_HW_SCANNING bit is set this function change
1015 * local->hw_scan_req to operate on 5G band, what race with
1016 * driver which can use local->hw_scan_req
1018 * - we can not cancel scan_work since driver can schedule it
1019 * by ieee80211_scan_completed(..., true) to finish scan
1021 * Hence we only call the cancel_hw_scan() callback, but the low-level
1022 * driver is still responsible for calling ieee80211_scan_completed()
1023 * after the scan was completed/aborted.
1026 mutex_lock(&local->mtx);
1027 if (!local->scan_req)
1031 * We have a scan running and the driver already reported completion,
1032 * but the worker hasn't run yet or is stuck on the mutex - mark it as
1035 if (test_bit(SCAN_HW_SCANNING, &local->scanning) &&
1036 test_bit(SCAN_COMPLETED, &local->scanning)) {
1037 set_bit(SCAN_HW_CANCELLED, &local->scanning);
1041 if (test_bit(SCAN_HW_SCANNING, &local->scanning)) {
1043 * Make sure that __ieee80211_scan_completed doesn't trigger a
1044 * scan on another band.
1046 set_bit(SCAN_HW_CANCELLED, &local->scanning);
1047 if (local->ops->cancel_hw_scan)
1048 drv_cancel_hw_scan(local,
1049 rcu_dereference_protected(local->scan_sdata,
1050 lockdep_is_held(&local->mtx)));
1055 * If the work is currently running, it must be blocked on
1056 * the mutex, but we'll set scan_sdata = NULL and it'll
1057 * simply exit once it acquires the mutex.
1059 cancel_delayed_work(&local->scan_work);
1061 __ieee80211_scan_completed(&local->hw, true);
1063 mutex_unlock(&local->mtx);
1066 int __ieee80211_request_sched_scan_start(struct ieee80211_sub_if_data *sdata,
1067 struct cfg80211_sched_scan_request *req)
1069 struct ieee80211_local *local = sdata->local;
1070 struct ieee80211_scan_ies sched_scan_ies = {};
1071 struct cfg80211_chan_def chandef;
1072 int ret, i, iebufsz, num_bands = 0;
1073 u32 rate_masks[IEEE80211_NUM_BANDS] = {};
1078 iebufsz = local->scan_ies_len + req->ie_len;
1080 lockdep_assert_held(&local->mtx);
1082 if (!local->ops->sched_scan_start)
1085 for (i = 0; i < IEEE80211_NUM_BANDS; i++) {
1086 if (local->hw.wiphy->bands[i]) {
1087 bands_used |= BIT(i);
1088 rate_masks[i] = (u32) -1;
1093 ie = kzalloc(num_bands * iebufsz, GFP_KERNEL);
1099 ieee80211_prepare_scan_chandef(&chandef, req->scan_width);
1101 len = ieee80211_build_preq_ies(local, ie, num_bands * iebufsz,
1102 &sched_scan_ies, req->ie,
1103 req->ie_len, bands_used,
1104 rate_masks, &chandef);
1106 ret = drv_sched_scan_start(local, sdata, req, &sched_scan_ies);
1108 rcu_assign_pointer(local->sched_scan_sdata, sdata);
1109 rcu_assign_pointer(local->sched_scan_req, req);
1116 /* Clean in case of failure after HW restart or upon resume. */
1117 RCU_INIT_POINTER(local->sched_scan_sdata, NULL);
1118 RCU_INIT_POINTER(local->sched_scan_req, NULL);
1124 int ieee80211_request_sched_scan_start(struct ieee80211_sub_if_data *sdata,
1125 struct cfg80211_sched_scan_request *req)
1127 struct ieee80211_local *local = sdata->local;
1130 mutex_lock(&local->mtx);
1132 if (rcu_access_pointer(local->sched_scan_sdata)) {
1133 mutex_unlock(&local->mtx);
1137 ret = __ieee80211_request_sched_scan_start(sdata, req);
1139 mutex_unlock(&local->mtx);
1143 int ieee80211_request_sched_scan_stop(struct ieee80211_local *local)
1145 struct ieee80211_sub_if_data *sched_scan_sdata;
1148 mutex_lock(&local->mtx);
1150 if (!local->ops->sched_scan_stop) {
1155 /* We don't want to restart sched scan anymore. */
1156 RCU_INIT_POINTER(local->sched_scan_req, NULL);
1158 sched_scan_sdata = rcu_dereference_protected(local->sched_scan_sdata,
1159 lockdep_is_held(&local->mtx));
1160 if (sched_scan_sdata) {
1161 ret = drv_sched_scan_stop(local, sched_scan_sdata);
1163 RCU_INIT_POINTER(local->sched_scan_sdata, NULL);
1166 mutex_unlock(&local->mtx);
1171 void ieee80211_sched_scan_results(struct ieee80211_hw *hw)
1173 struct ieee80211_local *local = hw_to_local(hw);
1175 trace_api_sched_scan_results(local);
1177 cfg80211_sched_scan_results(hw->wiphy);
1179 EXPORT_SYMBOL(ieee80211_sched_scan_results);
1181 void ieee80211_sched_scan_end(struct ieee80211_local *local)
1183 mutex_lock(&local->mtx);
1185 if (!rcu_access_pointer(local->sched_scan_sdata)) {
1186 mutex_unlock(&local->mtx);
1190 RCU_INIT_POINTER(local->sched_scan_sdata, NULL);
1192 /* If sched scan was aborted by the driver. */
1193 RCU_INIT_POINTER(local->sched_scan_req, NULL);
1195 mutex_unlock(&local->mtx);
1197 cfg80211_sched_scan_stopped(local->hw.wiphy);
1200 void ieee80211_sched_scan_stopped_work(struct work_struct *work)
1202 struct ieee80211_local *local =
1203 container_of(work, struct ieee80211_local,
1204 sched_scan_stopped_work);
1206 ieee80211_sched_scan_end(local);
1209 void ieee80211_sched_scan_stopped(struct ieee80211_hw *hw)
1211 struct ieee80211_local *local = hw_to_local(hw);
1213 trace_api_sched_scan_stopped(local);
1215 schedule_work(&local->sched_scan_stopped_work);
1217 EXPORT_SYMBOL(ieee80211_sched_scan_stopped);