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0001 // SPDX-License-Identifier: GPL-2.0-only
0002 /*
0003  * Scanning implementation
0004  *
0005  * Copyright 2003, Jouni Malinen <jkmaline@cc.hut.fi>
0006  * Copyright 2004, Instant802 Networks, Inc.
0007  * Copyright 2005, Devicescape Software, Inc.
0008  * Copyright 2006-2007  Jiri Benc <jbenc@suse.cz>
0009  * Copyright 2007, Michael Wu <flamingice@sourmilk.net>
0010  * Copyright 2013-2015  Intel Mobile Communications GmbH
0011  * Copyright 2016-2017  Intel Deutschland GmbH
0012  * Copyright (C) 2018-2021 Intel Corporation
0013  */
0014 
0015 #include <linux/if_arp.h>
0016 #include <linux/etherdevice.h>
0017 #include <linux/rtnetlink.h>
0018 #include <net/sch_generic.h>
0019 #include <linux/slab.h>
0020 #include <linux/export.h>
0021 #include <linux/random.h>
0022 #include <net/mac80211.h>
0023 
0024 #include "ieee80211_i.h"
0025 #include "driver-ops.h"
0026 #include "mesh.h"
0027 
0028 #define IEEE80211_PROBE_DELAY (HZ / 33)
0029 #define IEEE80211_CHANNEL_TIME (HZ / 33)
0030 #define IEEE80211_PASSIVE_CHANNEL_TIME (HZ / 9)
0031 
0032 void ieee80211_rx_bss_put(struct ieee80211_local *local,
0033               struct ieee80211_bss *bss)
0034 {
0035     if (!bss)
0036         return;
0037     cfg80211_put_bss(local->hw.wiphy,
0038              container_of((void *)bss, struct cfg80211_bss, priv));
0039 }
0040 
0041 static bool is_uapsd_supported(struct ieee802_11_elems *elems)
0042 {
0043     u8 qos_info;
0044 
0045     if (elems->wmm_info && elems->wmm_info_len == 7
0046         && elems->wmm_info[5] == 1)
0047         qos_info = elems->wmm_info[6];
0048     else if (elems->wmm_param && elems->wmm_param_len == 24
0049          && elems->wmm_param[5] == 1)
0050         qos_info = elems->wmm_param[6];
0051     else
0052         /* no valid wmm information or parameter element found */
0053         return false;
0054 
0055     return qos_info & IEEE80211_WMM_IE_AP_QOSINFO_UAPSD;
0056 }
0057 
0058 static void
0059 ieee80211_update_bss_from_elems(struct ieee80211_local *local,
0060                 struct ieee80211_bss *bss,
0061                 struct ieee802_11_elems *elems,
0062                 struct ieee80211_rx_status *rx_status,
0063                 bool beacon)
0064 {
0065     int clen, srlen;
0066 
0067     if (beacon)
0068         bss->device_ts_beacon = rx_status->device_timestamp;
0069     else
0070         bss->device_ts_presp = rx_status->device_timestamp;
0071 
0072     if (elems->parse_error) {
0073         if (beacon)
0074             bss->corrupt_data |= IEEE80211_BSS_CORRUPT_BEACON;
0075         else
0076             bss->corrupt_data |= IEEE80211_BSS_CORRUPT_PROBE_RESP;
0077     } else {
0078         if (beacon)
0079             bss->corrupt_data &= ~IEEE80211_BSS_CORRUPT_BEACON;
0080         else
0081             bss->corrupt_data &= ~IEEE80211_BSS_CORRUPT_PROBE_RESP;
0082     }
0083 
0084     /* save the ERP value so that it is available at association time */
0085     if (elems->erp_info && (!elems->parse_error ||
0086                 !(bss->valid_data & IEEE80211_BSS_VALID_ERP))) {
0087         bss->erp_value = elems->erp_info[0];
0088         bss->has_erp_value = true;
0089         if (!elems->parse_error)
0090             bss->valid_data |= IEEE80211_BSS_VALID_ERP;
0091     }
0092 
0093     /* replace old supported rates if we get new values */
0094     if (!elems->parse_error ||
0095         !(bss->valid_data & IEEE80211_BSS_VALID_RATES)) {
0096         srlen = 0;
0097         if (elems->supp_rates) {
0098             clen = IEEE80211_MAX_SUPP_RATES;
0099             if (clen > elems->supp_rates_len)
0100                 clen = elems->supp_rates_len;
0101             memcpy(bss->supp_rates, elems->supp_rates, clen);
0102             srlen += clen;
0103         }
0104         if (elems->ext_supp_rates) {
0105             clen = IEEE80211_MAX_SUPP_RATES - srlen;
0106             if (clen > elems->ext_supp_rates_len)
0107                 clen = elems->ext_supp_rates_len;
0108             memcpy(bss->supp_rates + srlen, elems->ext_supp_rates,
0109                    clen);
0110             srlen += clen;
0111         }
0112         if (srlen) {
0113             bss->supp_rates_len = srlen;
0114             if (!elems->parse_error)
0115                 bss->valid_data |= IEEE80211_BSS_VALID_RATES;
0116         }
0117     }
0118 
0119     if (!elems->parse_error ||
0120         !(bss->valid_data & IEEE80211_BSS_VALID_WMM)) {
0121         bss->wmm_used = elems->wmm_param || elems->wmm_info;
0122         bss->uapsd_supported = is_uapsd_supported(elems);
0123         if (!elems->parse_error)
0124             bss->valid_data |= IEEE80211_BSS_VALID_WMM;
0125     }
0126 
0127     if (beacon) {
0128         struct ieee80211_supported_band *sband =
0129             local->hw.wiphy->bands[rx_status->band];
0130         if (!(rx_status->encoding == RX_ENC_HT) &&
0131             !(rx_status->encoding == RX_ENC_VHT))
0132             bss->beacon_rate =
0133                 &sband->bitrates[rx_status->rate_idx];
0134     }
0135 
0136     if (elems->vht_cap_elem)
0137         bss->vht_cap_info =
0138             le32_to_cpu(elems->vht_cap_elem->vht_cap_info);
0139     else
0140         bss->vht_cap_info = 0;
0141 }
0142 
0143 struct ieee80211_bss *
0144 ieee80211_bss_info_update(struct ieee80211_local *local,
0145               struct ieee80211_rx_status *rx_status,
0146               struct ieee80211_mgmt *mgmt, size_t len,
0147               struct ieee80211_channel *channel)
0148 {
0149     bool beacon = ieee80211_is_beacon(mgmt->frame_control) ||
0150               ieee80211_is_s1g_beacon(mgmt->frame_control);
0151     struct cfg80211_bss *cbss, *non_tx_cbss;
0152     struct ieee80211_bss *bss, *non_tx_bss;
0153     struct cfg80211_inform_bss bss_meta = {
0154         .boottime_ns = rx_status->boottime_ns,
0155     };
0156     bool signal_valid;
0157     struct ieee80211_sub_if_data *scan_sdata;
0158     struct ieee802_11_elems *elems;
0159     size_t baselen;
0160     u8 *elements;
0161 
0162     if (rx_status->flag & RX_FLAG_NO_SIGNAL_VAL)
0163         bss_meta.signal = 0; /* invalid signal indication */
0164     else if (ieee80211_hw_check(&local->hw, SIGNAL_DBM))
0165         bss_meta.signal = rx_status->signal * 100;
0166     else if (ieee80211_hw_check(&local->hw, SIGNAL_UNSPEC))
0167         bss_meta.signal = (rx_status->signal * 100) / local->hw.max_signal;
0168 
0169     bss_meta.scan_width = NL80211_BSS_CHAN_WIDTH_20;
0170     if (rx_status->bw == RATE_INFO_BW_5)
0171         bss_meta.scan_width = NL80211_BSS_CHAN_WIDTH_5;
0172     else if (rx_status->bw == RATE_INFO_BW_10)
0173         bss_meta.scan_width = NL80211_BSS_CHAN_WIDTH_10;
0174 
0175     bss_meta.chan = channel;
0176 
0177     rcu_read_lock();
0178     scan_sdata = rcu_dereference(local->scan_sdata);
0179     if (scan_sdata && scan_sdata->vif.type == NL80211_IFTYPE_STATION &&
0180         scan_sdata->vif.cfg.assoc &&
0181         ieee80211_have_rx_timestamp(rx_status)) {
0182         bss_meta.parent_tsf =
0183             ieee80211_calculate_rx_timestamp(local, rx_status,
0184                              len + FCS_LEN, 24);
0185         ether_addr_copy(bss_meta.parent_bssid,
0186                 scan_sdata->vif.bss_conf.bssid);
0187     }
0188     rcu_read_unlock();
0189 
0190     cbss = cfg80211_inform_bss_frame_data(local->hw.wiphy, &bss_meta,
0191                           mgmt, len, GFP_ATOMIC);
0192     if (!cbss)
0193         return NULL;
0194 
0195     if (ieee80211_is_probe_resp(mgmt->frame_control)) {
0196         elements = mgmt->u.probe_resp.variable;
0197         baselen = offsetof(struct ieee80211_mgmt,
0198                    u.probe_resp.variable);
0199     } else if (ieee80211_is_s1g_beacon(mgmt->frame_control)) {
0200         struct ieee80211_ext *ext = (void *) mgmt;
0201 
0202         baselen = offsetof(struct ieee80211_ext, u.s1g_beacon.variable);
0203         elements = ext->u.s1g_beacon.variable;
0204     } else {
0205         baselen = offsetof(struct ieee80211_mgmt, u.beacon.variable);
0206         elements = mgmt->u.beacon.variable;
0207     }
0208 
0209     if (baselen > len)
0210         return NULL;
0211 
0212     elems = ieee802_11_parse_elems(elements, len - baselen, false, cbss);
0213     if (!elems)
0214         return NULL;
0215 
0216     /* In case the signal is invalid update the status */
0217     signal_valid = channel == cbss->channel;
0218     if (!signal_valid)
0219         rx_status->flag |= RX_FLAG_NO_SIGNAL_VAL;
0220 
0221     bss = (void *)cbss->priv;
0222     ieee80211_update_bss_from_elems(local, bss, elems, rx_status, beacon);
0223     kfree(elems);
0224 
0225     list_for_each_entry(non_tx_cbss, &cbss->nontrans_list, nontrans_list) {
0226         non_tx_bss = (void *)non_tx_cbss->priv;
0227 
0228         elems = ieee802_11_parse_elems(elements, len - baselen, false,
0229                            non_tx_cbss);
0230         if (!elems)
0231             continue;
0232 
0233         ieee80211_update_bss_from_elems(local, non_tx_bss, elems,
0234                         rx_status, beacon);
0235         kfree(elems);
0236     }
0237 
0238     return bss;
0239 }
0240 
0241 static bool ieee80211_scan_accept_presp(struct ieee80211_sub_if_data *sdata,
0242                     u32 scan_flags, const u8 *da)
0243 {
0244     if (!sdata)
0245         return false;
0246     /* accept broadcast for OCE */
0247     if (scan_flags & NL80211_SCAN_FLAG_ACCEPT_BCAST_PROBE_RESP &&
0248         is_broadcast_ether_addr(da))
0249         return true;
0250     if (scan_flags & NL80211_SCAN_FLAG_RANDOM_ADDR)
0251         return true;
0252     return ether_addr_equal(da, sdata->vif.addr);
0253 }
0254 
0255 void ieee80211_scan_rx(struct ieee80211_local *local, struct sk_buff *skb)
0256 {
0257     struct ieee80211_rx_status *rx_status = IEEE80211_SKB_RXCB(skb);
0258     struct ieee80211_sub_if_data *sdata1, *sdata2;
0259     struct ieee80211_mgmt *mgmt = (void *)skb->data;
0260     struct ieee80211_bss *bss;
0261     struct ieee80211_channel *channel;
0262     size_t min_hdr_len = offsetof(struct ieee80211_mgmt,
0263                       u.probe_resp.variable);
0264 
0265     if (!ieee80211_is_probe_resp(mgmt->frame_control) &&
0266         !ieee80211_is_beacon(mgmt->frame_control) &&
0267         !ieee80211_is_s1g_beacon(mgmt->frame_control))
0268         return;
0269 
0270     if (ieee80211_is_s1g_beacon(mgmt->frame_control)) {
0271         if (ieee80211_is_s1g_short_beacon(mgmt->frame_control))
0272             min_hdr_len = offsetof(struct ieee80211_ext,
0273                            u.s1g_short_beacon.variable);
0274         else
0275             min_hdr_len = offsetof(struct ieee80211_ext,
0276                            u.s1g_beacon);
0277     }
0278 
0279     if (skb->len < min_hdr_len)
0280         return;
0281 
0282     sdata1 = rcu_dereference(local->scan_sdata);
0283     sdata2 = rcu_dereference(local->sched_scan_sdata);
0284 
0285     if (likely(!sdata1 && !sdata2))
0286         return;
0287 
0288     if (test_and_clear_bit(SCAN_BEACON_WAIT, &local->scanning)) {
0289         /*
0290          * we were passive scanning because of radar/no-IR, but
0291          * the beacon/proberesp rx gives us an opportunity to upgrade
0292          * to active scan
0293          */
0294          set_bit(SCAN_BEACON_DONE, &local->scanning);
0295          ieee80211_queue_delayed_work(&local->hw, &local->scan_work, 0);
0296     }
0297 
0298     if (ieee80211_is_probe_resp(mgmt->frame_control)) {
0299         struct cfg80211_scan_request *scan_req;
0300         struct cfg80211_sched_scan_request *sched_scan_req;
0301         u32 scan_req_flags = 0, sched_scan_req_flags = 0;
0302 
0303         scan_req = rcu_dereference(local->scan_req);
0304         sched_scan_req = rcu_dereference(local->sched_scan_req);
0305 
0306         if (scan_req)
0307             scan_req_flags = scan_req->flags;
0308 
0309         if (sched_scan_req)
0310             sched_scan_req_flags = sched_scan_req->flags;
0311 
0312         /* ignore ProbeResp to foreign address or non-bcast (OCE)
0313          * unless scanning with randomised address
0314          */
0315         if (!ieee80211_scan_accept_presp(sdata1, scan_req_flags,
0316                          mgmt->da) &&
0317             !ieee80211_scan_accept_presp(sdata2, sched_scan_req_flags,
0318                          mgmt->da))
0319             return;
0320     }
0321 
0322     channel = ieee80211_get_channel_khz(local->hw.wiphy,
0323                     ieee80211_rx_status_to_khz(rx_status));
0324 
0325     if (!channel || channel->flags & IEEE80211_CHAN_DISABLED)
0326         return;
0327 
0328     bss = ieee80211_bss_info_update(local, rx_status,
0329                     mgmt, skb->len,
0330                     channel);
0331     if (bss)
0332         ieee80211_rx_bss_put(local, bss);
0333 }
0334 
0335 static void
0336 ieee80211_prepare_scan_chandef(struct cfg80211_chan_def *chandef,
0337                    enum nl80211_bss_scan_width scan_width)
0338 {
0339     memset(chandef, 0, sizeof(*chandef));
0340     switch (scan_width) {
0341     case NL80211_BSS_CHAN_WIDTH_5:
0342         chandef->width = NL80211_CHAN_WIDTH_5;
0343         break;
0344     case NL80211_BSS_CHAN_WIDTH_10:
0345         chandef->width = NL80211_CHAN_WIDTH_10;
0346         break;
0347     default:
0348         chandef->width = NL80211_CHAN_WIDTH_20_NOHT;
0349         break;
0350     }
0351 }
0352 
0353 /* return false if no more work */
0354 static bool ieee80211_prep_hw_scan(struct ieee80211_sub_if_data *sdata)
0355 {
0356     struct ieee80211_local *local = sdata->local;
0357     struct cfg80211_scan_request *req;
0358     struct cfg80211_chan_def chandef;
0359     u8 bands_used = 0;
0360     int i, ielen, n_chans;
0361     u32 flags = 0;
0362 
0363     req = rcu_dereference_protected(local->scan_req,
0364                     lockdep_is_held(&local->mtx));
0365 
0366     if (test_bit(SCAN_HW_CANCELLED, &local->scanning))
0367         return false;
0368 
0369     if (ieee80211_hw_check(&local->hw, SINGLE_SCAN_ON_ALL_BANDS)) {
0370         for (i = 0; i < req->n_channels; i++) {
0371             local->hw_scan_req->req.channels[i] = req->channels[i];
0372             bands_used |= BIT(req->channels[i]->band);
0373         }
0374 
0375         n_chans = req->n_channels;
0376     } else {
0377         do {
0378             if (local->hw_scan_band == NUM_NL80211_BANDS)
0379                 return false;
0380 
0381             n_chans = 0;
0382 
0383             for (i = 0; i < req->n_channels; i++) {
0384                 if (req->channels[i]->band !=
0385                     local->hw_scan_band)
0386                     continue;
0387                 local->hw_scan_req->req.channels[n_chans] =
0388                             req->channels[i];
0389                 n_chans++;
0390                 bands_used |= BIT(req->channels[i]->band);
0391             }
0392 
0393             local->hw_scan_band++;
0394         } while (!n_chans);
0395     }
0396 
0397     local->hw_scan_req->req.n_channels = n_chans;
0398     ieee80211_prepare_scan_chandef(&chandef, req->scan_width);
0399 
0400     if (req->flags & NL80211_SCAN_FLAG_MIN_PREQ_CONTENT)
0401         flags |= IEEE80211_PROBE_FLAG_MIN_CONTENT;
0402 
0403     ielen = ieee80211_build_preq_ies(sdata,
0404                      (u8 *)local->hw_scan_req->req.ie,
0405                      local->hw_scan_ies_bufsize,
0406                      &local->hw_scan_req->ies,
0407                      req->ie, req->ie_len,
0408                      bands_used, req->rates, &chandef,
0409                      flags);
0410     local->hw_scan_req->req.ie_len = ielen;
0411     local->hw_scan_req->req.no_cck = req->no_cck;
0412     ether_addr_copy(local->hw_scan_req->req.mac_addr, req->mac_addr);
0413     ether_addr_copy(local->hw_scan_req->req.mac_addr_mask,
0414             req->mac_addr_mask);
0415     ether_addr_copy(local->hw_scan_req->req.bssid, req->bssid);
0416 
0417     return true;
0418 }
0419 
0420 static void __ieee80211_scan_completed(struct ieee80211_hw *hw, bool aborted)
0421 {
0422     struct ieee80211_local *local = hw_to_local(hw);
0423     bool hw_scan = test_bit(SCAN_HW_SCANNING, &local->scanning);
0424     bool was_scanning = local->scanning;
0425     struct cfg80211_scan_request *scan_req;
0426     struct ieee80211_sub_if_data *scan_sdata;
0427     struct ieee80211_sub_if_data *sdata;
0428 
0429     lockdep_assert_held(&local->mtx);
0430 
0431     /*
0432      * It's ok to abort a not-yet-running scan (that
0433      * we have one at all will be verified by checking
0434      * local->scan_req next), but not to complete it
0435      * successfully.
0436      */
0437     if (WARN_ON(!local->scanning && !aborted))
0438         aborted = true;
0439 
0440     if (WARN_ON(!local->scan_req))
0441         return;
0442 
0443     scan_sdata = rcu_dereference_protected(local->scan_sdata,
0444                            lockdep_is_held(&local->mtx));
0445 
0446     if (hw_scan && !aborted &&
0447         !ieee80211_hw_check(&local->hw, SINGLE_SCAN_ON_ALL_BANDS) &&
0448         ieee80211_prep_hw_scan(scan_sdata)) {
0449         int rc;
0450 
0451         rc = drv_hw_scan(local,
0452             rcu_dereference_protected(local->scan_sdata,
0453                           lockdep_is_held(&local->mtx)),
0454             local->hw_scan_req);
0455 
0456         if (rc == 0)
0457             return;
0458 
0459         /* HW scan failed and is going to be reported as aborted,
0460          * so clear old scan info.
0461          */
0462         memset(&local->scan_info, 0, sizeof(local->scan_info));
0463         aborted = true;
0464     }
0465 
0466     kfree(local->hw_scan_req);
0467     local->hw_scan_req = NULL;
0468 
0469     scan_req = rcu_dereference_protected(local->scan_req,
0470                          lockdep_is_held(&local->mtx));
0471 
0472     RCU_INIT_POINTER(local->scan_req, NULL);
0473     RCU_INIT_POINTER(local->scan_sdata, NULL);
0474 
0475     local->scanning = 0;
0476     local->scan_chandef.chan = NULL;
0477 
0478     synchronize_rcu();
0479 
0480     if (scan_req != local->int_scan_req) {
0481         local->scan_info.aborted = aborted;
0482         cfg80211_scan_done(scan_req, &local->scan_info);
0483     }
0484 
0485     /* Set power back to normal operating levels. */
0486     ieee80211_hw_config(local, 0);
0487 
0488     if (!hw_scan) {
0489         ieee80211_configure_filter(local);
0490         drv_sw_scan_complete(local, scan_sdata);
0491         ieee80211_offchannel_return(local);
0492     }
0493 
0494     ieee80211_recalc_idle(local);
0495 
0496     ieee80211_mlme_notify_scan_completed(local);
0497     ieee80211_ibss_notify_scan_completed(local);
0498 
0499     /* Requeue all the work that might have been ignored while
0500      * the scan was in progress; if there was none this will
0501      * just be a no-op for the particular interface.
0502      */
0503     list_for_each_entry_rcu(sdata, &local->interfaces, list) {
0504         if (ieee80211_sdata_running(sdata))
0505             ieee80211_queue_work(&sdata->local->hw, &sdata->work);
0506     }
0507 
0508     if (was_scanning)
0509         ieee80211_start_next_roc(local);
0510 }
0511 
0512 void ieee80211_scan_completed(struct ieee80211_hw *hw,
0513                   struct cfg80211_scan_info *info)
0514 {
0515     struct ieee80211_local *local = hw_to_local(hw);
0516 
0517     trace_api_scan_completed(local, info->aborted);
0518 
0519     set_bit(SCAN_COMPLETED, &local->scanning);
0520     if (info->aborted)
0521         set_bit(SCAN_ABORTED, &local->scanning);
0522 
0523     memcpy(&local->scan_info, info, sizeof(*info));
0524 
0525     ieee80211_queue_delayed_work(&local->hw, &local->scan_work, 0);
0526 }
0527 EXPORT_SYMBOL(ieee80211_scan_completed);
0528 
0529 static int ieee80211_start_sw_scan(struct ieee80211_local *local,
0530                    struct ieee80211_sub_if_data *sdata)
0531 {
0532     /* Software scan is not supported in multi-channel cases */
0533     if (local->use_chanctx)
0534         return -EOPNOTSUPP;
0535 
0536     /*
0537      * Hardware/driver doesn't support hw_scan, so use software
0538      * scanning instead. First send a nullfunc frame with power save
0539      * bit on so that AP will buffer the frames for us while we are not
0540      * listening, then send probe requests to each channel and wait for
0541      * the responses. After all channels are scanned, tune back to the
0542      * original channel and send a nullfunc frame with power save bit
0543      * off to trigger the AP to send us all the buffered frames.
0544      *
0545      * Note that while local->sw_scanning is true everything else but
0546      * nullfunc frames and probe requests will be dropped in
0547      * ieee80211_tx_h_check_assoc().
0548      */
0549     drv_sw_scan_start(local, sdata, local->scan_addr);
0550 
0551     local->leave_oper_channel_time = jiffies;
0552     local->next_scan_state = SCAN_DECISION;
0553     local->scan_channel_idx = 0;
0554 
0555     ieee80211_offchannel_stop_vifs(local);
0556 
0557     /* ensure nullfunc is transmitted before leaving operating channel */
0558     ieee80211_flush_queues(local, NULL, false);
0559 
0560     ieee80211_configure_filter(local);
0561 
0562     /* We need to set power level at maximum rate for scanning. */
0563     ieee80211_hw_config(local, 0);
0564 
0565     ieee80211_queue_delayed_work(&local->hw,
0566                      &local->scan_work, 0);
0567 
0568     return 0;
0569 }
0570 
0571 static bool __ieee80211_can_leave_ch(struct ieee80211_sub_if_data *sdata)
0572 {
0573     struct ieee80211_local *local = sdata->local;
0574     struct ieee80211_sub_if_data *sdata_iter;
0575 
0576     if (!ieee80211_is_radar_required(local))
0577         return true;
0578 
0579     if (!regulatory_pre_cac_allowed(local->hw.wiphy))
0580         return false;
0581 
0582     mutex_lock(&local->iflist_mtx);
0583     list_for_each_entry(sdata_iter, &local->interfaces, list) {
0584         if (sdata_iter->wdev.cac_started) {
0585             mutex_unlock(&local->iflist_mtx);
0586             return false;
0587         }
0588     }
0589     mutex_unlock(&local->iflist_mtx);
0590 
0591     return true;
0592 }
0593 
0594 static bool ieee80211_can_scan(struct ieee80211_local *local,
0595                    struct ieee80211_sub_if_data *sdata)
0596 {
0597     if (!__ieee80211_can_leave_ch(sdata))
0598         return false;
0599 
0600     if (!list_empty(&local->roc_list))
0601         return false;
0602 
0603     if (sdata->vif.type == NL80211_IFTYPE_STATION &&
0604         sdata->u.mgd.flags & IEEE80211_STA_CONNECTION_POLL)
0605         return false;
0606 
0607     return true;
0608 }
0609 
0610 void ieee80211_run_deferred_scan(struct ieee80211_local *local)
0611 {
0612     lockdep_assert_held(&local->mtx);
0613 
0614     if (!local->scan_req || local->scanning)
0615         return;
0616 
0617     if (!ieee80211_can_scan(local,
0618                 rcu_dereference_protected(
0619                     local->scan_sdata,
0620                     lockdep_is_held(&local->mtx))))
0621         return;
0622 
0623     ieee80211_queue_delayed_work(&local->hw, &local->scan_work,
0624                      round_jiffies_relative(0));
0625 }
0626 
0627 static void ieee80211_send_scan_probe_req(struct ieee80211_sub_if_data *sdata,
0628                       const u8 *src, const u8 *dst,
0629                       const u8 *ssid, size_t ssid_len,
0630                       const u8 *ie, size_t ie_len,
0631                       u32 ratemask, u32 flags, u32 tx_flags,
0632                       struct ieee80211_channel *channel)
0633 {
0634     struct sk_buff *skb;
0635 
0636     skb = ieee80211_build_probe_req(sdata, src, dst, ratemask, channel,
0637                     ssid, ssid_len,
0638                     ie, ie_len, flags);
0639 
0640     if (skb) {
0641         if (flags & IEEE80211_PROBE_FLAG_RANDOM_SN) {
0642             struct ieee80211_hdr *hdr = (void *)skb->data;
0643             struct ieee80211_tx_info *info = IEEE80211_SKB_CB(skb);
0644             u16 sn = get_random_u32();
0645 
0646             info->control.flags |= IEEE80211_TX_CTRL_NO_SEQNO;
0647             hdr->seq_ctrl =
0648                 cpu_to_le16(IEEE80211_SN_TO_SEQ(sn));
0649         }
0650         IEEE80211_SKB_CB(skb)->flags |= tx_flags;
0651         ieee80211_tx_skb_tid_band(sdata, skb, 7, channel->band);
0652     }
0653 }
0654 
0655 static void ieee80211_scan_state_send_probe(struct ieee80211_local *local,
0656                         unsigned long *next_delay)
0657 {
0658     int i;
0659     struct ieee80211_sub_if_data *sdata;
0660     struct cfg80211_scan_request *scan_req;
0661     enum nl80211_band band = local->hw.conf.chandef.chan->band;
0662     u32 flags = 0, tx_flags;
0663 
0664     scan_req = rcu_dereference_protected(local->scan_req,
0665                          lockdep_is_held(&local->mtx));
0666 
0667     tx_flags = IEEE80211_TX_INTFL_OFFCHAN_TX_OK;
0668     if (scan_req->no_cck)
0669         tx_flags |= IEEE80211_TX_CTL_NO_CCK_RATE;
0670     if (scan_req->flags & NL80211_SCAN_FLAG_MIN_PREQ_CONTENT)
0671         flags |= IEEE80211_PROBE_FLAG_MIN_CONTENT;
0672     if (scan_req->flags & NL80211_SCAN_FLAG_RANDOM_SN)
0673         flags |= IEEE80211_PROBE_FLAG_RANDOM_SN;
0674 
0675     sdata = rcu_dereference_protected(local->scan_sdata,
0676                       lockdep_is_held(&local->mtx));
0677 
0678     for (i = 0; i < scan_req->n_ssids; i++)
0679         ieee80211_send_scan_probe_req(
0680             sdata, local->scan_addr, scan_req->bssid,
0681             scan_req->ssids[i].ssid, scan_req->ssids[i].ssid_len,
0682             scan_req->ie, scan_req->ie_len,
0683             scan_req->rates[band], flags,
0684             tx_flags, local->hw.conf.chandef.chan);
0685 
0686     /*
0687      * After sending probe requests, wait for probe responses
0688      * on the channel.
0689      */
0690     *next_delay = IEEE80211_CHANNEL_TIME;
0691     local->next_scan_state = SCAN_DECISION;
0692 }
0693 
0694 static int __ieee80211_start_scan(struct ieee80211_sub_if_data *sdata,
0695                   struct cfg80211_scan_request *req)
0696 {
0697     struct ieee80211_local *local = sdata->local;
0698     bool hw_scan = local->ops->hw_scan;
0699     int rc;
0700 
0701     lockdep_assert_held(&local->mtx);
0702 
0703     if (local->scan_req)
0704         return -EBUSY;
0705 
0706     if (!__ieee80211_can_leave_ch(sdata))
0707         return -EBUSY;
0708 
0709     if (!ieee80211_can_scan(local, sdata)) {
0710         /* wait for the work to finish/time out */
0711         rcu_assign_pointer(local->scan_req, req);
0712         rcu_assign_pointer(local->scan_sdata, sdata);
0713         return 0;
0714     }
0715 
0716  again:
0717     if (hw_scan) {
0718         u8 *ies;
0719 
0720         local->hw_scan_ies_bufsize = local->scan_ies_len + req->ie_len;
0721 
0722         if (ieee80211_hw_check(&local->hw, SINGLE_SCAN_ON_ALL_BANDS)) {
0723             int i, n_bands = 0;
0724             u8 bands_counted = 0;
0725 
0726             for (i = 0; i < req->n_channels; i++) {
0727                 if (bands_counted & BIT(req->channels[i]->band))
0728                     continue;
0729                 bands_counted |= BIT(req->channels[i]->band);
0730                 n_bands++;
0731             }
0732 
0733             local->hw_scan_ies_bufsize *= n_bands;
0734         }
0735 
0736         local->hw_scan_req = kmalloc(
0737                 sizeof(*local->hw_scan_req) +
0738                 req->n_channels * sizeof(req->channels[0]) +
0739                 local->hw_scan_ies_bufsize, GFP_KERNEL);
0740         if (!local->hw_scan_req)
0741             return -ENOMEM;
0742 
0743         local->hw_scan_req->req.ssids = req->ssids;
0744         local->hw_scan_req->req.n_ssids = req->n_ssids;
0745         ies = (u8 *)local->hw_scan_req +
0746             sizeof(*local->hw_scan_req) +
0747             req->n_channels * sizeof(req->channels[0]);
0748         local->hw_scan_req->req.ie = ies;
0749         local->hw_scan_req->req.flags = req->flags;
0750         eth_broadcast_addr(local->hw_scan_req->req.bssid);
0751         local->hw_scan_req->req.duration = req->duration;
0752         local->hw_scan_req->req.duration_mandatory =
0753             req->duration_mandatory;
0754 
0755         local->hw_scan_band = 0;
0756         local->hw_scan_req->req.n_6ghz_params = req->n_6ghz_params;
0757         local->hw_scan_req->req.scan_6ghz_params =
0758             req->scan_6ghz_params;
0759         local->hw_scan_req->req.scan_6ghz = req->scan_6ghz;
0760 
0761         /*
0762          * After allocating local->hw_scan_req, we must
0763          * go through until ieee80211_prep_hw_scan(), so
0764          * anything that might be changed here and leave
0765          * this function early must not go after this
0766          * allocation.
0767          */
0768     }
0769 
0770     rcu_assign_pointer(local->scan_req, req);
0771     rcu_assign_pointer(local->scan_sdata, sdata);
0772 
0773     if (req->flags & NL80211_SCAN_FLAG_RANDOM_ADDR)
0774         get_random_mask_addr(local->scan_addr,
0775                      req->mac_addr,
0776                      req->mac_addr_mask);
0777     else
0778         memcpy(local->scan_addr, sdata->vif.addr, ETH_ALEN);
0779 
0780     if (hw_scan) {
0781         __set_bit(SCAN_HW_SCANNING, &local->scanning);
0782     } else if ((req->n_channels == 1) &&
0783            (req->channels[0] == local->_oper_chandef.chan)) {
0784         /*
0785          * If we are scanning only on the operating channel
0786          * then we do not need to stop normal activities
0787          */
0788         unsigned long next_delay;
0789 
0790         __set_bit(SCAN_ONCHANNEL_SCANNING, &local->scanning);
0791 
0792         ieee80211_recalc_idle(local);
0793 
0794         /* Notify driver scan is starting, keep order of operations
0795          * same as normal software scan, in case that matters. */
0796         drv_sw_scan_start(local, sdata, local->scan_addr);
0797 
0798         ieee80211_configure_filter(local); /* accept probe-responses */
0799 
0800         /* We need to ensure power level is at max for scanning. */
0801         ieee80211_hw_config(local, 0);
0802 
0803         if ((req->channels[0]->flags & (IEEE80211_CHAN_NO_IR |
0804                         IEEE80211_CHAN_RADAR)) ||
0805             !req->n_ssids) {
0806             next_delay = IEEE80211_PASSIVE_CHANNEL_TIME;
0807             if (req->n_ssids)
0808                 set_bit(SCAN_BEACON_WAIT, &local->scanning);
0809         } else {
0810             ieee80211_scan_state_send_probe(local, &next_delay);
0811             next_delay = IEEE80211_CHANNEL_TIME;
0812         }
0813 
0814         /* Now, just wait a bit and we are all done! */
0815         ieee80211_queue_delayed_work(&local->hw, &local->scan_work,
0816                          next_delay);
0817         return 0;
0818     } else {
0819         /* Do normal software scan */
0820         __set_bit(SCAN_SW_SCANNING, &local->scanning);
0821     }
0822 
0823     ieee80211_recalc_idle(local);
0824 
0825     if (hw_scan) {
0826         WARN_ON(!ieee80211_prep_hw_scan(sdata));
0827         rc = drv_hw_scan(local, sdata, local->hw_scan_req);
0828     } else {
0829         rc = ieee80211_start_sw_scan(local, sdata);
0830     }
0831 
0832     if (rc) {
0833         kfree(local->hw_scan_req);
0834         local->hw_scan_req = NULL;
0835         local->scanning = 0;
0836 
0837         ieee80211_recalc_idle(local);
0838 
0839         local->scan_req = NULL;
0840         RCU_INIT_POINTER(local->scan_sdata, NULL);
0841     }
0842 
0843     if (hw_scan && rc == 1) {
0844         /*
0845          * we can't fall back to software for P2P-GO
0846          * as it must update NoA etc.
0847          */
0848         if (ieee80211_vif_type_p2p(&sdata->vif) ==
0849                 NL80211_IFTYPE_P2P_GO)
0850             return -EOPNOTSUPP;
0851         hw_scan = false;
0852         goto again;
0853     }
0854 
0855     return rc;
0856 }
0857 
0858 static unsigned long
0859 ieee80211_scan_get_channel_time(struct ieee80211_channel *chan)
0860 {
0861     /*
0862      * TODO: channel switching also consumes quite some time,
0863      * add that delay as well to get a better estimation
0864      */
0865     if (chan->flags & (IEEE80211_CHAN_NO_IR | IEEE80211_CHAN_RADAR))
0866         return IEEE80211_PASSIVE_CHANNEL_TIME;
0867     return IEEE80211_PROBE_DELAY + IEEE80211_CHANNEL_TIME;
0868 }
0869 
0870 static void ieee80211_scan_state_decision(struct ieee80211_local *local,
0871                       unsigned long *next_delay)
0872 {
0873     bool associated = false;
0874     bool tx_empty = true;
0875     bool bad_latency;
0876     struct ieee80211_sub_if_data *sdata;
0877     struct ieee80211_channel *next_chan;
0878     enum mac80211_scan_state next_scan_state;
0879     struct cfg80211_scan_request *scan_req;
0880 
0881     /*
0882      * check if at least one STA interface is associated,
0883      * check if at least one STA interface has pending tx frames
0884      * and grab the lowest used beacon interval
0885      */
0886     mutex_lock(&local->iflist_mtx);
0887     list_for_each_entry(sdata, &local->interfaces, list) {
0888         if (!ieee80211_sdata_running(sdata))
0889             continue;
0890 
0891         if (sdata->vif.type == NL80211_IFTYPE_STATION) {
0892             if (sdata->u.mgd.associated) {
0893                 associated = true;
0894 
0895                 if (!qdisc_all_tx_empty(sdata->dev)) {
0896                     tx_empty = false;
0897                     break;
0898                 }
0899             }
0900         }
0901     }
0902     mutex_unlock(&local->iflist_mtx);
0903 
0904     scan_req = rcu_dereference_protected(local->scan_req,
0905                          lockdep_is_held(&local->mtx));
0906 
0907     next_chan = scan_req->channels[local->scan_channel_idx];
0908 
0909     /*
0910      * we're currently scanning a different channel, let's
0911      * see if we can scan another channel without interfering
0912      * with the current traffic situation.
0913      *
0914      * Keep good latency, do not stay off-channel more than 125 ms.
0915      */
0916 
0917     bad_latency = time_after(jiffies +
0918                  ieee80211_scan_get_channel_time(next_chan),
0919                  local->leave_oper_channel_time + HZ / 8);
0920 
0921     if (associated && !tx_empty) {
0922         if (scan_req->flags & NL80211_SCAN_FLAG_LOW_PRIORITY)
0923             next_scan_state = SCAN_ABORT;
0924         else
0925             next_scan_state = SCAN_SUSPEND;
0926     } else if (associated && bad_latency) {
0927         next_scan_state = SCAN_SUSPEND;
0928     } else {
0929         next_scan_state = SCAN_SET_CHANNEL;
0930     }
0931 
0932     local->next_scan_state = next_scan_state;
0933 
0934     *next_delay = 0;
0935 }
0936 
0937 static void ieee80211_scan_state_set_channel(struct ieee80211_local *local,
0938                          unsigned long *next_delay)
0939 {
0940     int skip;
0941     struct ieee80211_channel *chan;
0942     enum nl80211_bss_scan_width oper_scan_width;
0943     struct cfg80211_scan_request *scan_req;
0944 
0945     scan_req = rcu_dereference_protected(local->scan_req,
0946                          lockdep_is_held(&local->mtx));
0947 
0948     skip = 0;
0949     chan = scan_req->channels[local->scan_channel_idx];
0950 
0951     local->scan_chandef.chan = chan;
0952     local->scan_chandef.center_freq1 = chan->center_freq;
0953     local->scan_chandef.freq1_offset = chan->freq_offset;
0954     local->scan_chandef.center_freq2 = 0;
0955 
0956     /* For scanning on the S1G band, ignore scan_width (which is constant
0957      * across all channels) for now since channel width is specific to each
0958      * channel. Detect the required channel width here and likely revisit
0959      * later. Maybe scan_width could be used to build the channel scan list?
0960      */
0961     if (chan->band == NL80211_BAND_S1GHZ) {
0962         local->scan_chandef.width = ieee80211_s1g_channel_width(chan);
0963         goto set_channel;
0964     }
0965 
0966     switch (scan_req->scan_width) {
0967     case NL80211_BSS_CHAN_WIDTH_5:
0968         local->scan_chandef.width = NL80211_CHAN_WIDTH_5;
0969         break;
0970     case NL80211_BSS_CHAN_WIDTH_10:
0971         local->scan_chandef.width = NL80211_CHAN_WIDTH_10;
0972         break;
0973     default:
0974     case NL80211_BSS_CHAN_WIDTH_20:
0975         /* If scanning on oper channel, use whatever channel-type
0976          * is currently in use.
0977          */
0978         oper_scan_width = cfg80211_chandef_to_scan_width(
0979                     &local->_oper_chandef);
0980         if (chan == local->_oper_chandef.chan &&
0981             oper_scan_width == scan_req->scan_width)
0982             local->scan_chandef = local->_oper_chandef;
0983         else
0984             local->scan_chandef.width = NL80211_CHAN_WIDTH_20_NOHT;
0985         break;
0986     case NL80211_BSS_CHAN_WIDTH_1:
0987     case NL80211_BSS_CHAN_WIDTH_2:
0988         /* shouldn't get here, S1G handled above */
0989         WARN_ON(1);
0990         break;
0991     }
0992 
0993 set_channel:
0994     if (ieee80211_hw_config(local, IEEE80211_CONF_CHANGE_CHANNEL))
0995         skip = 1;
0996 
0997     /* advance state machine to next channel/band */
0998     local->scan_channel_idx++;
0999 
1000     if (skip) {
1001         /* if we skip this channel return to the decision state */
1002         local->next_scan_state = SCAN_DECISION;
1003         return;
1004     }
1005 
1006     /*
1007      * Probe delay is used to update the NAV, cf. 11.1.3.2.2
1008      * (which unfortunately doesn't say _why_ step a) is done,
1009      * but it waits for the probe delay or until a frame is
1010      * received - and the received frame would update the NAV).
1011      * For now, we do not support waiting until a frame is
1012      * received.
1013      *
1014      * In any case, it is not necessary for a passive scan.
1015      */
1016     if ((chan->flags & (IEEE80211_CHAN_NO_IR | IEEE80211_CHAN_RADAR)) ||
1017         !scan_req->n_ssids) {
1018         *next_delay = IEEE80211_PASSIVE_CHANNEL_TIME;
1019         local->next_scan_state = SCAN_DECISION;
1020         if (scan_req->n_ssids)
1021             set_bit(SCAN_BEACON_WAIT, &local->scanning);
1022         return;
1023     }
1024 
1025     /* active scan, send probes */
1026     *next_delay = IEEE80211_PROBE_DELAY;
1027     local->next_scan_state = SCAN_SEND_PROBE;
1028 }
1029 
1030 static void ieee80211_scan_state_suspend(struct ieee80211_local *local,
1031                      unsigned long *next_delay)
1032 {
1033     /* switch back to the operating channel */
1034     local->scan_chandef.chan = NULL;
1035     ieee80211_hw_config(local, IEEE80211_CONF_CHANGE_CHANNEL);
1036 
1037     /* disable PS */
1038     ieee80211_offchannel_return(local);
1039 
1040     *next_delay = HZ / 5;
1041     /* afterwards, resume scan & go to next channel */
1042     local->next_scan_state = SCAN_RESUME;
1043 }
1044 
1045 static void ieee80211_scan_state_resume(struct ieee80211_local *local,
1046                     unsigned long *next_delay)
1047 {
1048     ieee80211_offchannel_stop_vifs(local);
1049 
1050     if (local->ops->flush) {
1051         ieee80211_flush_queues(local, NULL, false);
1052         *next_delay = 0;
1053     } else
1054         *next_delay = HZ / 10;
1055 
1056     /* remember when we left the operating channel */
1057     local->leave_oper_channel_time = jiffies;
1058 
1059     /* advance to the next channel to be scanned */
1060     local->next_scan_state = SCAN_SET_CHANNEL;
1061 }
1062 
1063 void ieee80211_scan_work(struct work_struct *work)
1064 {
1065     struct ieee80211_local *local =
1066         container_of(work, struct ieee80211_local, scan_work.work);
1067     struct ieee80211_sub_if_data *sdata;
1068     struct cfg80211_scan_request *scan_req;
1069     unsigned long next_delay = 0;
1070     bool aborted;
1071 
1072     mutex_lock(&local->mtx);
1073 
1074     if (!ieee80211_can_run_worker(local)) {
1075         aborted = true;
1076         goto out_complete;
1077     }
1078 
1079     sdata = rcu_dereference_protected(local->scan_sdata,
1080                       lockdep_is_held(&local->mtx));
1081     scan_req = rcu_dereference_protected(local->scan_req,
1082                          lockdep_is_held(&local->mtx));
1083 
1084     /* When scanning on-channel, the first-callback means completed. */
1085     if (test_bit(SCAN_ONCHANNEL_SCANNING, &local->scanning)) {
1086         aborted = test_and_clear_bit(SCAN_ABORTED, &local->scanning);
1087         goto out_complete;
1088     }
1089 
1090     if (test_and_clear_bit(SCAN_COMPLETED, &local->scanning)) {
1091         aborted = test_and_clear_bit(SCAN_ABORTED, &local->scanning);
1092         goto out_complete;
1093     }
1094 
1095     if (!sdata || !scan_req)
1096         goto out;
1097 
1098     if (!local->scanning) {
1099         int rc;
1100 
1101         RCU_INIT_POINTER(local->scan_req, NULL);
1102         RCU_INIT_POINTER(local->scan_sdata, NULL);
1103 
1104         rc = __ieee80211_start_scan(sdata, scan_req);
1105         if (rc) {
1106             /* need to complete scan in cfg80211 */
1107             rcu_assign_pointer(local->scan_req, scan_req);
1108             aborted = true;
1109             goto out_complete;
1110         } else
1111             goto out;
1112     }
1113 
1114     clear_bit(SCAN_BEACON_WAIT, &local->scanning);
1115 
1116     /*
1117      * as long as no delay is required advance immediately
1118      * without scheduling a new work
1119      */
1120     do {
1121         if (!ieee80211_sdata_running(sdata)) {
1122             aborted = true;
1123             goto out_complete;
1124         }
1125 
1126         if (test_and_clear_bit(SCAN_BEACON_DONE, &local->scanning) &&
1127             local->next_scan_state == SCAN_DECISION)
1128             local->next_scan_state = SCAN_SEND_PROBE;
1129 
1130         switch (local->next_scan_state) {
1131         case SCAN_DECISION:
1132             /* if no more bands/channels left, complete scan */
1133             if (local->scan_channel_idx >= scan_req->n_channels) {
1134                 aborted = false;
1135                 goto out_complete;
1136             }
1137             ieee80211_scan_state_decision(local, &next_delay);
1138             break;
1139         case SCAN_SET_CHANNEL:
1140             ieee80211_scan_state_set_channel(local, &next_delay);
1141             break;
1142         case SCAN_SEND_PROBE:
1143             ieee80211_scan_state_send_probe(local, &next_delay);
1144             break;
1145         case SCAN_SUSPEND:
1146             ieee80211_scan_state_suspend(local, &next_delay);
1147             break;
1148         case SCAN_RESUME:
1149             ieee80211_scan_state_resume(local, &next_delay);
1150             break;
1151         case SCAN_ABORT:
1152             aborted = true;
1153             goto out_complete;
1154         }
1155     } while (next_delay == 0);
1156 
1157     ieee80211_queue_delayed_work(&local->hw, &local->scan_work, next_delay);
1158     goto out;
1159 
1160 out_complete:
1161     __ieee80211_scan_completed(&local->hw, aborted);
1162 out:
1163     mutex_unlock(&local->mtx);
1164 }
1165 
1166 int ieee80211_request_scan(struct ieee80211_sub_if_data *sdata,
1167                struct cfg80211_scan_request *req)
1168 {
1169     int res;
1170 
1171     mutex_lock(&sdata->local->mtx);
1172     res = __ieee80211_start_scan(sdata, req);
1173     mutex_unlock(&sdata->local->mtx);
1174 
1175     return res;
1176 }
1177 
1178 int ieee80211_request_ibss_scan(struct ieee80211_sub_if_data *sdata,
1179                 const u8 *ssid, u8 ssid_len,
1180                 struct ieee80211_channel **channels,
1181                 unsigned int n_channels,
1182                 enum nl80211_bss_scan_width scan_width)
1183 {
1184     struct ieee80211_local *local = sdata->local;
1185     int ret = -EBUSY, i, n_ch = 0;
1186     enum nl80211_band band;
1187 
1188     mutex_lock(&local->mtx);
1189 
1190     /* busy scanning */
1191     if (local->scan_req)
1192         goto unlock;
1193 
1194     /* fill internal scan request */
1195     if (!channels) {
1196         int max_n;
1197 
1198         for (band = 0; band < NUM_NL80211_BANDS; band++) {
1199             if (!local->hw.wiphy->bands[band] ||
1200                 band == NL80211_BAND_6GHZ)
1201                 continue;
1202 
1203             max_n = local->hw.wiphy->bands[band]->n_channels;
1204             for (i = 0; i < max_n; i++) {
1205                 struct ieee80211_channel *tmp_ch =
1206                     &local->hw.wiphy->bands[band]->channels[i];
1207 
1208                 if (tmp_ch->flags & (IEEE80211_CHAN_NO_IR |
1209                              IEEE80211_CHAN_DISABLED))
1210                     continue;
1211 
1212                 local->int_scan_req->channels[n_ch] = tmp_ch;
1213                 n_ch++;
1214             }
1215         }
1216 
1217         if (WARN_ON_ONCE(n_ch == 0))
1218             goto unlock;
1219 
1220         local->int_scan_req->n_channels = n_ch;
1221     } else {
1222         for (i = 0; i < n_channels; i++) {
1223             if (channels[i]->flags & (IEEE80211_CHAN_NO_IR |
1224                           IEEE80211_CHAN_DISABLED))
1225                 continue;
1226 
1227             local->int_scan_req->channels[n_ch] = channels[i];
1228             n_ch++;
1229         }
1230 
1231         if (WARN_ON_ONCE(n_ch == 0))
1232             goto unlock;
1233 
1234         local->int_scan_req->n_channels = n_ch;
1235     }
1236 
1237     local->int_scan_req->ssids = &local->scan_ssid;
1238     local->int_scan_req->n_ssids = 1;
1239     local->int_scan_req->scan_width = scan_width;
1240     memcpy(local->int_scan_req->ssids[0].ssid, ssid, IEEE80211_MAX_SSID_LEN);
1241     local->int_scan_req->ssids[0].ssid_len = ssid_len;
1242 
1243     ret = __ieee80211_start_scan(sdata, sdata->local->int_scan_req);
1244  unlock:
1245     mutex_unlock(&local->mtx);
1246     return ret;
1247 }
1248 
1249 /*
1250  * Only call this function when a scan can't be queued -- under RTNL.
1251  */
1252 void ieee80211_scan_cancel(struct ieee80211_local *local)
1253 {
1254     /*
1255      * We are canceling software scan, or deferred scan that was not
1256      * yet really started (see __ieee80211_start_scan ).
1257      *
1258      * Regarding hardware scan:
1259      * - we can not call  __ieee80211_scan_completed() as when
1260      *   SCAN_HW_SCANNING bit is set this function change
1261      *   local->hw_scan_req to operate on 5G band, what race with
1262      *   driver which can use local->hw_scan_req
1263      *
1264      * - we can not cancel scan_work since driver can schedule it
1265      *   by ieee80211_scan_completed(..., true) to finish scan
1266      *
1267      * Hence we only call the cancel_hw_scan() callback, but the low-level
1268      * driver is still responsible for calling ieee80211_scan_completed()
1269      * after the scan was completed/aborted.
1270      */
1271 
1272     mutex_lock(&local->mtx);
1273     if (!local->scan_req)
1274         goto out;
1275 
1276     /*
1277      * We have a scan running and the driver already reported completion,
1278      * but the worker hasn't run yet or is stuck on the mutex - mark it as
1279      * cancelled.
1280      */
1281     if (test_bit(SCAN_HW_SCANNING, &local->scanning) &&
1282         test_bit(SCAN_COMPLETED, &local->scanning)) {
1283         set_bit(SCAN_HW_CANCELLED, &local->scanning);
1284         goto out;
1285     }
1286 
1287     if (test_bit(SCAN_HW_SCANNING, &local->scanning)) {
1288         /*
1289          * Make sure that __ieee80211_scan_completed doesn't trigger a
1290          * scan on another band.
1291          */
1292         set_bit(SCAN_HW_CANCELLED, &local->scanning);
1293         if (local->ops->cancel_hw_scan)
1294             drv_cancel_hw_scan(local,
1295                 rcu_dereference_protected(local->scan_sdata,
1296                         lockdep_is_held(&local->mtx)));
1297         goto out;
1298     }
1299 
1300     /*
1301      * If the work is currently running, it must be blocked on
1302      * the mutex, but we'll set scan_sdata = NULL and it'll
1303      * simply exit once it acquires the mutex.
1304      */
1305     cancel_delayed_work(&local->scan_work);
1306     /* and clean up */
1307     memset(&local->scan_info, 0, sizeof(local->scan_info));
1308     __ieee80211_scan_completed(&local->hw, true);
1309 out:
1310     mutex_unlock(&local->mtx);
1311 }
1312 
1313 int __ieee80211_request_sched_scan_start(struct ieee80211_sub_if_data *sdata,
1314                     struct cfg80211_sched_scan_request *req)
1315 {
1316     struct ieee80211_local *local = sdata->local;
1317     struct ieee80211_scan_ies sched_scan_ies = {};
1318     struct cfg80211_chan_def chandef;
1319     int ret, i, iebufsz, num_bands = 0;
1320     u32 rate_masks[NUM_NL80211_BANDS] = {};
1321     u8 bands_used = 0;
1322     u8 *ie;
1323     u32 flags = 0;
1324 
1325     iebufsz = local->scan_ies_len + req->ie_len;
1326 
1327     lockdep_assert_held(&local->mtx);
1328 
1329     if (!local->ops->sched_scan_start)
1330         return -ENOTSUPP;
1331 
1332     for (i = 0; i < NUM_NL80211_BANDS; i++) {
1333         if (local->hw.wiphy->bands[i]) {
1334             bands_used |= BIT(i);
1335             rate_masks[i] = (u32) -1;
1336             num_bands++;
1337         }
1338     }
1339 
1340     if (req->flags & NL80211_SCAN_FLAG_MIN_PREQ_CONTENT)
1341         flags |= IEEE80211_PROBE_FLAG_MIN_CONTENT;
1342 
1343     ie = kcalloc(iebufsz, num_bands, GFP_KERNEL);
1344     if (!ie) {
1345         ret = -ENOMEM;
1346         goto out;
1347     }
1348 
1349     ieee80211_prepare_scan_chandef(&chandef, req->scan_width);
1350 
1351     ieee80211_build_preq_ies(sdata, ie, num_bands * iebufsz,
1352                  &sched_scan_ies, req->ie,
1353                  req->ie_len, bands_used, rate_masks, &chandef,
1354                  flags);
1355 
1356     ret = drv_sched_scan_start(local, sdata, req, &sched_scan_ies);
1357     if (ret == 0) {
1358         rcu_assign_pointer(local->sched_scan_sdata, sdata);
1359         rcu_assign_pointer(local->sched_scan_req, req);
1360     }
1361 
1362     kfree(ie);
1363 
1364 out:
1365     if (ret) {
1366         /* Clean in case of failure after HW restart or upon resume. */
1367         RCU_INIT_POINTER(local->sched_scan_sdata, NULL);
1368         RCU_INIT_POINTER(local->sched_scan_req, NULL);
1369     }
1370 
1371     return ret;
1372 }
1373 
1374 int ieee80211_request_sched_scan_start(struct ieee80211_sub_if_data *sdata,
1375                        struct cfg80211_sched_scan_request *req)
1376 {
1377     struct ieee80211_local *local = sdata->local;
1378     int ret;
1379 
1380     mutex_lock(&local->mtx);
1381 
1382     if (rcu_access_pointer(local->sched_scan_sdata)) {
1383         mutex_unlock(&local->mtx);
1384         return -EBUSY;
1385     }
1386 
1387     ret = __ieee80211_request_sched_scan_start(sdata, req);
1388 
1389     mutex_unlock(&local->mtx);
1390     return ret;
1391 }
1392 
1393 int ieee80211_request_sched_scan_stop(struct ieee80211_local *local)
1394 {
1395     struct ieee80211_sub_if_data *sched_scan_sdata;
1396     int ret = -ENOENT;
1397 
1398     mutex_lock(&local->mtx);
1399 
1400     if (!local->ops->sched_scan_stop) {
1401         ret = -ENOTSUPP;
1402         goto out;
1403     }
1404 
1405     /* We don't want to restart sched scan anymore. */
1406     RCU_INIT_POINTER(local->sched_scan_req, NULL);
1407 
1408     sched_scan_sdata = rcu_dereference_protected(local->sched_scan_sdata,
1409                         lockdep_is_held(&local->mtx));
1410     if (sched_scan_sdata) {
1411         ret = drv_sched_scan_stop(local, sched_scan_sdata);
1412         if (!ret)
1413             RCU_INIT_POINTER(local->sched_scan_sdata, NULL);
1414     }
1415 out:
1416     mutex_unlock(&local->mtx);
1417 
1418     return ret;
1419 }
1420 
1421 void ieee80211_sched_scan_results(struct ieee80211_hw *hw)
1422 {
1423     struct ieee80211_local *local = hw_to_local(hw);
1424 
1425     trace_api_sched_scan_results(local);
1426 
1427     cfg80211_sched_scan_results(hw->wiphy, 0);
1428 }
1429 EXPORT_SYMBOL(ieee80211_sched_scan_results);
1430 
1431 void ieee80211_sched_scan_end(struct ieee80211_local *local)
1432 {
1433     mutex_lock(&local->mtx);
1434 
1435     if (!rcu_access_pointer(local->sched_scan_sdata)) {
1436         mutex_unlock(&local->mtx);
1437         return;
1438     }
1439 
1440     RCU_INIT_POINTER(local->sched_scan_sdata, NULL);
1441 
1442     /* If sched scan was aborted by the driver. */
1443     RCU_INIT_POINTER(local->sched_scan_req, NULL);
1444 
1445     mutex_unlock(&local->mtx);
1446 
1447     cfg80211_sched_scan_stopped(local->hw.wiphy, 0);
1448 }
1449 
1450 void ieee80211_sched_scan_stopped_work(struct work_struct *work)
1451 {
1452     struct ieee80211_local *local =
1453         container_of(work, struct ieee80211_local,
1454                  sched_scan_stopped_work);
1455 
1456     ieee80211_sched_scan_end(local);
1457 }
1458 
1459 void ieee80211_sched_scan_stopped(struct ieee80211_hw *hw)
1460 {
1461     struct ieee80211_local *local = hw_to_local(hw);
1462 
1463     trace_api_sched_scan_stopped(local);
1464 
1465     /*
1466      * this shouldn't really happen, so for simplicity
1467      * simply ignore it, and let mac80211 reconfigure
1468      * the sched scan later on.
1469      */
1470     if (local->in_reconfig)
1471         return;
1472 
1473     schedule_work(&local->sched_scan_stopped_work);
1474 }
1475 EXPORT_SYMBOL(ieee80211_sched_scan_stopped);
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