net/mac80211/scan.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  * Scanning implementation
   4  *
   5  * Copyright 2003, Jouni Malinen <jkmaline@cc.hut.fi>
   6  * Copyright 2004, Instant802 Networks, Inc.
   7  * Copyright 2005, Devicescape Software, Inc.
   8  * Copyright 2006-2007  Jiri Benc <jbenc@suse.cz>
   9  * Copyright 2007, Michael Wu <flamingice@sourmilk.net>
  10  * Copyright 2013-2015  Intel Mobile Communications GmbH
  11  * Copyright 2016-2017  Intel Deutschland GmbH
  12  * Copyright (C) 2018-2020 Intel Corporation
  13  */
  14
  15 #include <linux/if_arp.h>
  16 #include <linux/etherdevice.h>
  17 #include <linux/rtnetlink.h>
  18 #include <net/sch_generic.h>
  19 #include <linux/slab.h>
  20 #include <linux/export.h>
  21 #include <linux/random.h>
  22 #include <net/mac80211.h>
  23
  24 #include "ieee80211_i.h"
  25 #include "driver-ops.h"
  26 #include "mesh.h"
  27
  28 #define IEEE80211_PROBE_DELAY (HZ / 33)
  29 #define IEEE80211_CHANNEL_TIME (HZ / 33)
  30 #define IEEE80211_PASSIVE_CHANNEL_TIME (HZ / 9)
  31
  32 void ieee80211_rx_bss_put(struct ieee80211_local *local,
  33                           struct ieee80211_bss *bss)
  34 {
  35         if (!bss)
  36                 return;
  37         cfg80211_put_bss(local->hw.wiphy,
  38                          container_of((void *)bss, struct cfg80211_bss, priv));
  39 }
  40
  41 static bool is_uapsd_supported(struct ieee802_11_elems *elems)
  42 {
  43         u8 qos_info;
  44
  45         if (elems->wmm_info && elems->wmm_info_len == 7
  46             && elems->wmm_info[5] == 1)
  47                 qos_info = elems->wmm_info[6];
  48         else if (elems->wmm_param && elems->wmm_param_len == 24
  49                  && elems->wmm_param[5] == 1)
  50                 qos_info = elems->wmm_param[6];
  51         else
  52                 /* no valid wmm information or parameter element found */
  53                 return false;
  54
  55         return qos_info & IEEE80211_WMM_IE_AP_QOSINFO_UAPSD;
  56 }
  57
  58 static void
  59 ieee80211_update_bss_from_elems(struct ieee80211_local *local,
  60                                 struct ieee80211_bss *bss,
  61                                 struct ieee802_11_elems *elems,
  62                                 struct ieee80211_rx_status *rx_status,
  63                                 bool beacon)
  64 {
  65         int clen, srlen;
  66
  67         if (beacon)
  68                 bss->device_ts_beacon = rx_status->device_timestamp;
  69         else
  70                 bss->device_ts_presp = rx_status->device_timestamp;
  71
  72         if (elems->parse_error) {
  73                 if (beacon)
  74                         bss->corrupt_data |= IEEE80211_BSS_CORRUPT_BEACON;
  75                 else
  76                         bss->corrupt_data |= IEEE80211_BSS_CORRUPT_PROBE_RESP;
  77         } else {
  78                 if (beacon)
  79                         bss->corrupt_data &= ~IEEE80211_BSS_CORRUPT_BEACON;
  80                 else
  81                         bss->corrupt_data &= ~IEEE80211_BSS_CORRUPT_PROBE_RESP;
  82         }
  83
  84         /* save the ERP value so that it is available at association time */
  85         if (elems->erp_info && (!elems->parse_error ||
  86                                 !(bss->valid_data & IEEE80211_BSS_VALID_ERP))) {
  87                 bss->erp_value = elems->erp_info[0];
  88                 bss->has_erp_value = true;
  89                 if (!elems->parse_error)
  90                         bss->valid_data |= IEEE80211_BSS_VALID_ERP;
  91         }
  92
  93         /* replace old supported rates if we get new values */
  94         if (!elems->parse_error ||
  95             !(bss->valid_data & IEEE80211_BSS_VALID_RATES)) {
  96                 srlen = 0;
  97                 if (elems->supp_rates) {
  98                         clen = IEEE80211_MAX_SUPP_RATES;
  99                         if (clen > elems->supp_rates_len)
 100                                 clen = elems->supp_rates_len;
 101                         memcpy(bss->supp_rates, elems->supp_rates, clen);
 102                         srlen += clen;
 103                 }
 104                 if (elems->ext_supp_rates) {
 105                         clen = IEEE80211_MAX_SUPP_RATES - srlen;
 106                         if (clen > elems->ext_supp_rates_len)
 107                                 clen = elems->ext_supp_rates_len;
 108                         memcpy(bss->supp_rates + srlen, elems->ext_supp_rates,
 109                                clen);
 110                         srlen += clen;
 111                 }
 112                 if (srlen) {
 113                         bss->supp_rates_len = srlen;
 114                         if (!elems->parse_error)
 115                                 bss->valid_data |= IEEE80211_BSS_VALID_RATES;
 116                 }
 117         }
 118
 119         if (!elems->parse_error ||
 120             !(bss->valid_data & IEEE80211_BSS_VALID_WMM)) {
 121                 bss->wmm_used = elems->wmm_param || elems->wmm_info;
 122                 bss->uapsd_supported = is_uapsd_supported(elems);
 123                 if (!elems->parse_error)
 124                         bss->valid_data |= IEEE80211_BSS_VALID_WMM;
 125         }
 126
 127         if (beacon) {
 128                 struct ieee80211_supported_band *sband =
 129                         local->hw.wiphy->bands[rx_status->band];
 130                 if (!(rx_status->encoding == RX_ENC_HT) &&
 131                     !(rx_status->encoding == RX_ENC_VHT))
 132                         bss->beacon_rate =
 133                                 &sband->bitrates[rx_status->rate_idx];
 134         }
 135
 136         if (elems->vht_cap_elem)
 137                 bss->vht_cap_info =
 138                         le32_to_cpu(elems->vht_cap_elem->vht_cap_info);
 139         else
 140                 bss->vht_cap_info = 0;
 141 }
 142
 143 struct ieee80211_bss *
 144 ieee80211_bss_info_update(struct ieee80211_local *local,
 145                           struct ieee80211_rx_status *rx_status,
 146                           struct ieee80211_mgmt *mgmt, size_t len,
 147                           struct ieee80211_channel *channel)
 148 {
 149         bool beacon = ieee80211_is_beacon(mgmt->frame_control) ||
 150                       ieee80211_is_s1g_beacon(mgmt->frame_control);
 151         struct cfg80211_bss *cbss, *non_tx_cbss;
 152         struct ieee80211_bss *bss, *non_tx_bss;
 153         struct cfg80211_inform_bss bss_meta = {
 154                 .boottime_ns = rx_status->boottime_ns,
 155         };
 156         bool signal_valid;
 157         struct ieee80211_sub_if_data *scan_sdata;
 158         struct ieee802_11_elems elems;
 159         size_t baselen;
 160         u8 *elements;
 161
 162         if (rx_status->flag & RX_FLAG_NO_SIGNAL_VAL)
 163                 bss_meta.signal = 0; /* invalid signal indication */
 164         else if (ieee80211_hw_check(&local->hw, SIGNAL_DBM))
 165                 bss_meta.signal = rx_status->signal * 100;
 166         else if (ieee80211_hw_check(&local->hw, SIGNAL_UNSPEC))
 167                 bss_meta.signal = (rx_status->signal * 100) / local->hw.max_signal;
 168
 169         bss_meta.scan_width = NL80211_BSS_CHAN_WIDTH_20;
 170         if (rx_status->bw == RATE_INFO_BW_5)
 171                 bss_meta.scan_width = NL80211_BSS_CHAN_WIDTH_5;
 172         else if (rx_status->bw == RATE_INFO_BW_10)
 173                 bss_meta.scan_width = NL80211_BSS_CHAN_WIDTH_10;
 174
 175         bss_meta.chan = channel;
 176
 177         rcu_read_lock();
 178         scan_sdata = rcu_dereference(local->scan_sdata);
 179         if (scan_sdata && scan_sdata->vif.type == NL80211_IFTYPE_STATION &&
 180             scan_sdata->vif.bss_conf.assoc &&
 181             ieee80211_have_rx_timestamp(rx_status)) {
 182                 bss_meta.parent_tsf =
 183                         ieee80211_calculate_rx_timestamp(local, rx_status,
 184                                                          len + FCS_LEN, 24);
 185                 ether_addr_copy(bss_meta.parent_bssid,
 186                                 scan_sdata->vif.bss_conf.bssid);
 187         }
 188         rcu_read_unlock();
 189
 190         cbss = cfg80211_inform_bss_frame_data(local->hw.wiphy, &bss_meta,
 191                                               mgmt, len, GFP_ATOMIC);
 192         if (!cbss)
 193                 return NULL;
 194
 195         if (ieee80211_is_probe_resp(mgmt->frame_control)) {
 196                 elements = mgmt->u.probe_resp.variable;
 197                 baselen = offsetof(struct ieee80211_mgmt,
 198                                    u.probe_resp.variable);
 199         } else if (ieee80211_is_s1g_beacon(mgmt->frame_control)) {
 200                 struct ieee80211_ext *ext = (void *) mgmt;
 201
 202                 baselen = offsetof(struct ieee80211_ext, u.s1g_beacon.variable);
 203                 elements = ext->u.s1g_beacon.variable;
 204         } else {
 205                 baselen = offsetof(struct ieee80211_mgmt, u.beacon.variable);
 206                 elements = mgmt->u.beacon.variable;
 207         }
 208
 209         if (baselen > len)
 210                 return NULL;
 211
 212         ieee802_11_parse_elems(elements, len - baselen, false, &elems,
 213                                mgmt->bssid, cbss->bssid);
 214
 215         /* In case the signal is invalid update the status */
 216         signal_valid = channel == cbss->channel;
 217         if (!signal_valid)
 218                 rx_status->flag |= RX_FLAG_NO_SIGNAL_VAL;
 219
 220         bss = (void *)cbss->priv;
 221         ieee80211_update_bss_from_elems(local, bss, &elems, rx_status, beacon);
 222
 223         list_for_each_entry(non_tx_cbss, &cbss->nontrans_list, nontrans_list) {
 224                 non_tx_bss = (void *)non_tx_cbss->priv;
 225
 226                 ieee80211_update_bss_from_elems(local, non_tx_bss, &elems,
 227                                                 rx_status, beacon);
 228         }
 229
 230         return bss;
 231 }
 232
 233 static bool ieee80211_scan_accept_presp(struct ieee80211_sub_if_data *sdata,
 234                                         u32 scan_flags, const u8 *da)
 235 {
 236         if (!sdata)
 237                 return false;
 238         /* accept broadcast for OCE */
 239         if (scan_flags & NL80211_SCAN_FLAG_ACCEPT_BCAST_PROBE_RESP &&
 240             is_broadcast_ether_addr(da))
 241                 return true;
 242         if (scan_flags & NL80211_SCAN_FLAG_RANDOM_ADDR)
 243                 return true;
 244         return ether_addr_equal(da, sdata->vif.addr);
 245 }
 246
 247 void ieee80211_scan_rx(struct ieee80211_local *local, struct sk_buff *skb)
 248 {
 249         struct ieee80211_rx_status *rx_status = IEEE80211_SKB_RXCB(skb);
 250         struct ieee80211_sub_if_data *sdata1, *sdata2;
 251         struct ieee80211_mgmt *mgmt = (void *)skb->data;
 252         struct ieee80211_bss *bss;
 253         struct ieee80211_channel *channel;
 254         size_t min_hdr_len = offsetof(struct ieee80211_mgmt,
 255                                       u.probe_resp.variable);
 256
 257         if (!ieee80211_is_probe_resp(mgmt->frame_control) &&
 258             !ieee80211_is_beacon(mgmt->frame_control) &&
 259             !ieee80211_is_s1g_beacon(mgmt->frame_control))
 260                 return;
 261
 262         if (ieee80211_is_s1g_beacon(mgmt->frame_control)) {
 263                 if (ieee80211_is_s1g_short_beacon(mgmt->frame_control))
 264                         min_hdr_len = offsetof(struct ieee80211_ext,
 265                                                u.s1g_short_beacon.variable);
 266                 else
 267                         min_hdr_len = offsetof(struct ieee80211_ext,
 268                                                u.s1g_beacon);
 269         }
 270
 271         if (skb->len < min_hdr_len)
 272                 return;
 273
 274         sdata1 = rcu_dereference(local->scan_sdata);
 275         sdata2 = rcu_dereference(local->sched_scan_sdata);
 276
 277         if (likely(!sdata1 && !sdata2))
 278                 return;
 279
 280         if (test_and_clear_bit(SCAN_BEACON_WAIT, &local->scanning)) {
 281                 /*
 282                  * we were passive scanning because of radar/no-IR, but
 283                  * the beacon/proberesp rx gives us an opportunity to upgrade
 284                  * to active scan
 285                  */
 286                  set_bit(SCAN_BEACON_DONE, &local->scanning);
 287                  ieee80211_queue_delayed_work(&local->hw, &local->scan_work, 0);
 288         }
 289
 290         if (ieee80211_is_probe_resp(mgmt->frame_control)) {
 291                 struct cfg80211_scan_request *scan_req;
 292                 struct cfg80211_sched_scan_request *sched_scan_req;
 293                 u32 scan_req_flags = 0, sched_scan_req_flags = 0;
 294
 295                 scan_req = rcu_dereference(local->scan_req);
 296                 sched_scan_req = rcu_dereference(local->sched_scan_req);
 297
 298                 if (scan_req)
 299                         scan_req_flags = scan_req->flags;
 300
 301                 if (sched_scan_req)
 302                         sched_scan_req_flags = sched_scan_req->flags;
 303
 304                 /* ignore ProbeResp to foreign address or non-bcast (OCE)
 305                  * unless scanning with randomised address
 306                  */
 307                 if (!ieee80211_scan_accept_presp(sdata1, scan_req_flags,
 308                                                  mgmt->da) &&
 309                     !ieee80211_scan_accept_presp(sdata2, sched_scan_req_flags,
 310                                                  mgmt->da))
 311                         return;
 312         }
 313
 314         channel = ieee80211_get_channel_khz(local->hw.wiphy,
 315                                         ieee80211_rx_status_to_khz(rx_status));
 316
 317         if (!channel || channel->flags & IEEE80211_CHAN_DISABLED)
 318                 return;
 319
 320         bss = ieee80211_bss_info_update(local, rx_status,
 321                                         mgmt, skb->len,
 322                                         channel);
 323         if (bss)
 324                 ieee80211_rx_bss_put(local, bss);
 325 }
 326
 327 static void
 328 ieee80211_prepare_scan_chandef(struct cfg80211_chan_def *chandef,
 329                                enum nl80211_bss_scan_width scan_width)
 330 {
 331         memset(chandef, 0, sizeof(*chandef));
 332         switch (scan_width) {
 333         case NL80211_BSS_CHAN_WIDTH_5:
 334                 chandef->width = NL80211_CHAN_WIDTH_5;
 335                 break;
 336         case NL80211_BSS_CHAN_WIDTH_10:
 337                 chandef->width = NL80211_CHAN_WIDTH_10;
 338                 break;
 339         default:
 340                 chandef->width = NL80211_CHAN_WIDTH_20_NOHT;
 341                 break;
 342         }
 343 }
 344
 345 /* return false if no more work */
 346 static bool ieee80211_prep_hw_scan(struct ieee80211_sub_if_data *sdata)
 347 {
 348         struct ieee80211_local *local = sdata->local;
 349         struct cfg80211_scan_request *req;
 350         struct cfg80211_chan_def chandef;
 351         u8 bands_used = 0;
 352         int i, ielen, n_chans;
 353         u32 flags = 0;
 354
 355         req = rcu_dereference_protected(local->scan_req,
 356                                         lockdep_is_held(&local->mtx));
 357
 358         if (test_bit(SCAN_HW_CANCELLED, &local->scanning))
 359                 return false;
 360
 361         if (ieee80211_hw_check(&local->hw, SINGLE_SCAN_ON_ALL_BANDS)) {
 362                 for (i = 0; i < req->n_channels; i++) {
 363                         local->hw_scan_req->req.channels[i] = req->channels[i];
 364                         bands_used |= BIT(req->channels[i]->band);
 365                 }
 366
 367                 n_chans = req->n_channels;
 368         } else {
 369                 do {
 370                         if (local->hw_scan_band == NUM_NL80211_BANDS)
 371                                 return false;
 372
 373                         n_chans = 0;
 374
 375                         for (i = 0; i < req->n_channels; i++) {
 376                                 if (req->channels[i]->band !=
 377                                     local->hw_scan_band)
 378                                         continue;
 379                                 local->hw_scan_req->req.channels[n_chans] =
 380                                                         req->channels[i];
 381                                 n_chans++;
 382                                 bands_used |= BIT(req->channels[i]->band);
 383                         }
 384
 385                         local->hw_scan_band++;
 386                 } while (!n_chans);
 387         }
 388
 389         local->hw_scan_req->req.n_channels = n_chans;
 390         ieee80211_prepare_scan_chandef(&chandef, req->scan_width);
 391
 392         if (req->flags & NL80211_SCAN_FLAG_MIN_PREQ_CONTENT)
 393                 flags |= IEEE80211_PROBE_FLAG_MIN_CONTENT;
 394
 395         ielen = ieee80211_build_preq_ies(sdata,
 396                                          (u8 *)local->hw_scan_req->req.ie,
 397                                          local->hw_scan_ies_bufsize,
 398                                          &local->hw_scan_req->ies,
 399                                          req->ie, req->ie_len,
 400                                          bands_used, req->rates, &chandef,
 401                                          flags);
 402         local->hw_scan_req->req.ie_len = ielen;
 403         local->hw_scan_req->req.no_cck = req->no_cck;
 404         ether_addr_copy(local->hw_scan_req->req.mac_addr, req->mac_addr);
 405         ether_addr_copy(local->hw_scan_req->req.mac_addr_mask,
 406                         req->mac_addr_mask);
 407         ether_addr_copy(local->hw_scan_req->req.bssid, req->bssid);
 408
 409         return true;
 410 }
 411
 412 static void __ieee80211_scan_completed(struct ieee80211_hw *hw, bool aborted)
 413 {
 414         struct ieee80211_local *local = hw_to_local(hw);
 415         bool hw_scan = test_bit(SCAN_HW_SCANNING, &local->scanning);
 416         bool was_scanning = local->scanning;
 417         struct cfg80211_scan_request *scan_req;
 418         struct ieee80211_sub_if_data *scan_sdata;
 419         struct ieee80211_sub_if_data *sdata;
 420
 421         lockdep_assert_held(&local->mtx);
 422
 423         /*
 424          * It's ok to abort a not-yet-running scan (that
 425          * we have one at all will be verified by checking
 426          * local->scan_req next), but not to complete it
 427          * successfully.
 428          */
 429         if (WARN_ON(!local->scanning && !aborted))
 430                 aborted = true;
 431
 432         if (WARN_ON(!local->scan_req))
 433                 return;
 434
 435         scan_sdata = rcu_dereference_protected(local->scan_sdata,
 436                                                lockdep_is_held(&local->mtx));
 437
 438         if (hw_scan && !aborted &&
 439             !ieee80211_hw_check(&local->hw, SINGLE_SCAN_ON_ALL_BANDS) &&
 440             ieee80211_prep_hw_scan(scan_sdata)) {
 441                 int rc;
 442
 443                 rc = drv_hw_scan(local,
 444                         rcu_dereference_protected(local->scan_sdata,
 445                                                   lockdep_is_held(&local->mtx)),
 446                         local->hw_scan_req);
 447
 448                 if (rc == 0)
 449                         return;
 450
 451                 /* HW scan failed and is going to be reported as aborted,
 452                  * so clear old scan info.
 453                  */
 454                 memset(&local->scan_info, 0, sizeof(local->scan_info));
 455                 aborted = true;
 456         }
 457
 458         kfree(local->hw_scan_req);
 459         local->hw_scan_req = NULL;
 460
 461         scan_req = rcu_dereference_protected(local->scan_req,
 462                                              lockdep_is_held(&local->mtx));
 463
 464         if (scan_req != local->int_scan_req) {
 465                 local->scan_info.aborted = aborted;
 466                 cfg80211_scan_done(scan_req, &local->scan_info);
 467         }
 468         RCU_INIT_POINTER(local->scan_req, NULL);
 469         RCU_INIT_POINTER(local->scan_sdata, NULL);
 470
 471         local->scanning = 0;
 472         local->scan_chandef.chan = NULL;
 473
 474         /* Set power back to normal operating levels. */
 475         ieee80211_hw_config(local, 0);
 476
 477         if (!hw_scan) {
 478                 ieee80211_configure_filter(local);
 479                 drv_sw_scan_complete(local, scan_sdata);
 480                 ieee80211_offchannel_return(local);
 481         }
 482
 483         ieee80211_recalc_idle(local);
 484
 485         ieee80211_mlme_notify_scan_completed(local);
 486         ieee80211_ibss_notify_scan_completed(local);
 487
 488         /* Requeue all the work that might have been ignored while
 489          * the scan was in progress; if there was none this will
 490          * just be a no-op for the particular interface.
 491          */
 492         list_for_each_entry_rcu(sdata, &local->interfaces, list) {
 493                 if (ieee80211_sdata_running(sdata))
 494                         ieee80211_queue_work(&sdata->local->hw, &sdata->work);
 495         }
 496
 497         if (was_scanning)
 498                 ieee80211_start_next_roc(local);
 499 }
 500
 501 void ieee80211_scan_completed(struct ieee80211_hw *hw,
 502                               struct cfg80211_scan_info *info)
 503 {
 504         struct ieee80211_local *local = hw_to_local(hw);
 505
 506         trace_api_scan_completed(local, info->aborted);
 507
 508         set_bit(SCAN_COMPLETED, &local->scanning);
 509         if (info->aborted)
 510                 set_bit(SCAN_ABORTED, &local->scanning);
 511
 512         memcpy(&local->scan_info, info, sizeof(*info));
 513
 514         ieee80211_queue_delayed_work(&local->hw, &local->scan_work, 0);
 515 }
 516 EXPORT_SYMBOL(ieee80211_scan_completed);
 517
 518 static int ieee80211_start_sw_scan(struct ieee80211_local *local,
 519                                    struct ieee80211_sub_if_data *sdata)
 520 {
 521         /* Software scan is not supported in multi-channel cases */
 522         if (local->use_chanctx)
 523                 return -EOPNOTSUPP;
 524
 525         /*
 526          * Hardware/driver doesn't support hw_scan, so use software
 527          * scanning instead. First send a nullfunc frame with power save
 528          * bit on so that AP will buffer the frames for us while we are not
 529          * listening, then send probe requests to each channel and wait for
 530          * the responses. After all channels are scanned, tune back to the
 531          * original channel and send a nullfunc frame with power save bit
 532          * off to trigger the AP to send us all the buffered frames.
 533          *
 534          * Note that while local->sw_scanning is true everything else but
 535          * nullfunc frames and probe requests will be dropped in
 536          * ieee80211_tx_h_check_assoc().
 537          */
 538         drv_sw_scan_start(local, sdata, local->scan_addr);
 539
 540         local->leave_oper_channel_time = jiffies;
 541         local->next_scan_state = SCAN_DECISION;
 542         local->scan_channel_idx = 0;
 543
 544         ieee80211_offchannel_stop_vifs(local);
 545
 546         /* ensure nullfunc is transmitted before leaving operating channel */
 547         ieee80211_flush_queues(local, NULL, false);
 548
 549         ieee80211_configure_filter(local);
 550
 551         /* We need to set power level at maximum rate for scanning. */
 552         ieee80211_hw_config(local, 0);
 553
 554         ieee80211_queue_delayed_work(&local->hw,
 555                                      &local->scan_work, 0);
 556
 557         return 0;
 558 }
 559
 560 static bool __ieee80211_can_leave_ch(struct ieee80211_sub_if_data *sdata)
 561 {
 562         struct ieee80211_local *local = sdata->local;
 563         struct ieee80211_sub_if_data *sdata_iter;
 564
 565         if (!ieee80211_is_radar_required(local))
 566                 return true;
 567
 568         if (!regulatory_pre_cac_allowed(local->hw.wiphy))
 569                 return false;
 570
 571         mutex_lock(&local->iflist_mtx);
 572         list_for_each_entry(sdata_iter, &local->interfaces, list) {
 573                 if (sdata_iter->wdev.cac_started) {
 574                         mutex_unlock(&local->iflist_mtx);
 575                         return false;
 576                 }
 577         }
 578         mutex_unlock(&local->iflist_mtx);
 579
 580         return true;
 581 }
 582
 583 static bool ieee80211_can_scan(struct ieee80211_local *local,
 584                                struct ieee80211_sub_if_data *sdata)
 585 {
 586         if (!__ieee80211_can_leave_ch(sdata))
 587                 return false;
 588
 589         if (!list_empty(&local->roc_list))
 590                 return false;
 591
 592         if (sdata->vif.type == NL80211_IFTYPE_STATION &&
 593             sdata->u.mgd.flags & IEEE80211_STA_CONNECTION_POLL)
 594                 return false;
 595
 596         return true;
 597 }
 598
 599 void ieee80211_run_deferred_scan(struct ieee80211_local *local)
 600 {
 601         lockdep_assert_held(&local->mtx);
 602
 603         if (!local->scan_req || local->scanning)
 604                 return;
 605
 606         if (!ieee80211_can_scan(local,
 607                                 rcu_dereference_protected(
 608                                         local->scan_sdata,
 609                                         lockdep_is_held(&local->mtx))))
 610                 return;
 611
 612         ieee80211_queue_delayed_work(&local->hw, &local->scan_work,
 613                                      round_jiffies_relative(0));
 614 }
 615
 616 static void ieee80211_send_scan_probe_req(struct ieee80211_sub_if_data *sdata,
 617                                           const u8 *src, const u8 *dst,
 618                                           const u8 *ssid, size_t ssid_len,
 619                                           const u8 *ie, size_t ie_len,
 620                                           u32 ratemask, u32 flags, u32 tx_flags,
 621                                           struct ieee80211_channel *channel)
 622 {
 623         struct sk_buff *skb;
 624
 625         skb = ieee80211_build_probe_req(sdata, src, dst, ratemask, channel,
 626                                         ssid, ssid_len,
 627                                         ie, ie_len, flags);
 628
 629         if (skb) {
 630                 if (flags & IEEE80211_PROBE_FLAG_RANDOM_SN) {
 631                         struct ieee80211_hdr *hdr = (void *)skb->data;
 632                         struct ieee80211_tx_info *info = IEEE80211_SKB_CB(skb);
 633                         u16 sn = get_random_u32();
 634
 635                         info->control.flags |= IEEE80211_TX_CTRL_NO_SEQNO;
 636                         hdr->seq_ctrl =
 637                                 cpu_to_le16(IEEE80211_SN_TO_SEQ(sn));
 638                 }
 639                 IEEE80211_SKB_CB(skb)->flags |= tx_flags;
 640                 ieee80211_tx_skb_tid_band(sdata, skb, 7, channel->band);
 641         }
 642 }
 643
 644 static void ieee80211_scan_state_send_probe(struct ieee80211_local *local,
 645                                             unsigned long *next_delay)
 646 {
 647         int i;
 648         struct ieee80211_sub_if_data *sdata;
 649         struct cfg80211_scan_request *scan_req;
 650         enum nl80211_band band = local->hw.conf.chandef.chan->band;
 651         u32 flags = 0, tx_flags;
 652
 653         scan_req = rcu_dereference_protected(local->scan_req,
 654                                              lockdep_is_held(&local->mtx));
 655
 656         tx_flags = IEEE80211_TX_INTFL_OFFCHAN_TX_OK;
 657         if (scan_req->no_cck)
 658                 tx_flags |= IEEE80211_TX_CTL_NO_CCK_RATE;
 659         if (scan_req->flags & NL80211_SCAN_FLAG_MIN_PREQ_CONTENT)
 660                 flags |= IEEE80211_PROBE_FLAG_MIN_CONTENT;
 661         if (scan_req->flags & NL80211_SCAN_FLAG_RANDOM_SN)
 662                 flags |= IEEE80211_PROBE_FLAG_RANDOM_SN;
 663
 664         sdata = rcu_dereference_protected(local->scan_sdata,
 665                                           lockdep_is_held(&local->mtx));
 666
 667         for (i = 0; i < scan_req->n_ssids; i++)
 668                 ieee80211_send_scan_probe_req(
 669                         sdata, local->scan_addr, scan_req->bssid,
 670                         scan_req->ssids[i].ssid, scan_req->ssids[i].ssid_len,
 671                         scan_req->ie, scan_req->ie_len,
 672                         scan_req->rates[band], flags,
 673                         tx_flags, local->hw.conf.chandef.chan);
 674
 675         /*
 676          * After sending probe requests, wait for probe responses
 677          * on the channel.
 678          */
 679         *next_delay = IEEE80211_CHANNEL_TIME;
 680         local->next_scan_state = SCAN_DECISION;
 681 }
 682
 683 static int __ieee80211_start_scan(struct ieee80211_sub_if_data *sdata,
 684                                   struct cfg80211_scan_request *req)
 685 {
 686         struct ieee80211_local *local = sdata->local;
 687         bool hw_scan = local->ops->hw_scan;
 688         int rc;
 689
 690         lockdep_assert_held(&local->mtx);
 691
 692         if (local->scan_req)
 693                 return -EBUSY;
 694
 695         if (!__ieee80211_can_leave_ch(sdata))
 696                 return -EBUSY;
 697
 698         if (!ieee80211_can_scan(local, sdata)) {
 699                 /* wait for the work to finish/time out */
 700                 rcu_assign_pointer(local->scan_req, req);
 701                 rcu_assign_pointer(local->scan_sdata, sdata);
 702                 return 0;
 703         }
 704
 705  again:
 706         if (hw_scan) {
 707                 u8 *ies;
 708
 709                 local->hw_scan_ies_bufsize = local->scan_ies_len + req->ie_len;
 710
 711                 if (ieee80211_hw_check(&local->hw, SINGLE_SCAN_ON_ALL_BANDS)) {
 712                         int i, n_bands = 0;
 713                         u8 bands_counted = 0;
 714
 715                         for (i = 0; i < req->n_channels; i++) {
 716                                 if (bands_counted & BIT(req->channels[i]->band))
 717                                         continue;
 718                                 bands_counted |= BIT(req->channels[i]->band);
 719                                 n_bands++;
 720                         }
 721
 722                         local->hw_scan_ies_bufsize *= n_bands;
 723                 }
 724
 725                 local->hw_scan_req = kmalloc(
 726                                 sizeof(*local->hw_scan_req) +
 727                                 req->n_channels * sizeof(req->channels[0]) +
 728                                 local->hw_scan_ies_bufsize, GFP_KERNEL);
 729                 if (!local->hw_scan_req)
 730                         return -ENOMEM;
 731
 732                 local->hw_scan_req->req.ssids = req->ssids;
 733                 local->hw_scan_req->req.n_ssids = req->n_ssids;
 734                 ies = (u8 *)local->hw_scan_req +
 735                         sizeof(*local->hw_scan_req) +
 736                         req->n_channels * sizeof(req->channels[0]);
 737                 local->hw_scan_req->req.ie = ies;
 738                 local->hw_scan_req->req.flags = req->flags;
 739                 eth_broadcast_addr(local->hw_scan_req->req.bssid);
 740                 local->hw_scan_req->req.duration = req->duration;
 741                 local->hw_scan_req->req.duration_mandatory =
 742                         req->duration_mandatory;
 743
 744                 local->hw_scan_band = 0;
 745                 local->hw_scan_req->req.n_6ghz_params = req->n_6ghz_params;
 746                 local->hw_scan_req->req.scan_6ghz_params =
 747                         req->scan_6ghz_params;
 748                 local->hw_scan_req->req.scan_6ghz = req->scan_6ghz;
 749
 750                 /*
 751                  * After allocating local->hw_scan_req, we must
 752                  * go through until ieee80211_prep_hw_scan(), so
 753                  * anything that might be changed here and leave
 754                  * this function early must not go after this
 755                  * allocation.
 756                  */
 757         }
 758
 759         rcu_assign_pointer(local->scan_req, req);
 760         rcu_assign_pointer(local->scan_sdata, sdata);
 761
 762         if (req->flags & NL80211_SCAN_FLAG_RANDOM_ADDR)
 763                 get_random_mask_addr(local->scan_addr,
 764                                      req->mac_addr,
 765                                      req->mac_addr_mask);
 766         else
 767                 memcpy(local->scan_addr, sdata->vif.addr, ETH_ALEN);
 768
 769         if (hw_scan) {
 770                 __set_bit(SCAN_HW_SCANNING, &local->scanning);
 771         } else if ((req->n_channels == 1) &&
 772                    (req->channels[0] == local->_oper_chandef.chan)) {
 773                 /*
 774                  * If we are scanning only on the operating channel
 775                  * then we do not need to stop normal activities
 776                  */
 777                 unsigned long next_delay;
 778
 779                 __set_bit(SCAN_ONCHANNEL_SCANNING, &local->scanning);
 780
 781                 ieee80211_recalc_idle(local);
 782
 783                 /* Notify driver scan is starting, keep order of operations
 784                  * same as normal software scan, in case that matters. */
 785                 drv_sw_scan_start(local, sdata, local->scan_addr);
 786
 787                 ieee80211_configure_filter(local); /* accept probe-responses */
 788
 789                 /* We need to ensure power level is at max for scanning. */
 790                 ieee80211_hw_config(local, 0);
 791
 792                 if ((req->channels[0]->flags & (IEEE80211_CHAN_NO_IR |
 793                                                 IEEE80211_CHAN_RADAR)) ||
 794                     !req->n_ssids) {
 795                         next_delay = IEEE80211_PASSIVE_CHANNEL_TIME;
 796                         if (req->n_ssids)
 797                                 set_bit(SCAN_BEACON_WAIT, &local->scanning);
 798                 } else {
 799                         ieee80211_scan_state_send_probe(local, &next_delay);
 800                         next_delay = IEEE80211_CHANNEL_TIME;
 801                 }
 802
 803                 /* Now, just wait a bit and we are all done! */
 804                 ieee80211_queue_delayed_work(&local->hw, &local->scan_work,
 805                                              next_delay);
 806                 return 0;
 807         } else {
 808                 /* Do normal software scan */
 809                 __set_bit(SCAN_SW_SCANNING, &local->scanning);
 810         }
 811
 812         ieee80211_recalc_idle(local);
 813
 814         if (hw_scan) {
 815                 WARN_ON(!ieee80211_prep_hw_scan(sdata));
 816                 rc = drv_hw_scan(local, sdata, local->hw_scan_req);
 817         } else {
 818                 rc = ieee80211_start_sw_scan(local, sdata);
 819         }
 820
 821         if (rc) {
 822                 kfree(local->hw_scan_req);
 823                 local->hw_scan_req = NULL;
 824                 local->scanning = 0;
 825
 826                 ieee80211_recalc_idle(local);
 827
 828                 local->scan_req = NULL;
 829                 RCU_INIT_POINTER(local->scan_sdata, NULL);
 830         }
 831
 832         if (hw_scan && rc == 1) {
 833                 /*
 834                  * we can't fall back to software for P2P-GO
 835                  * as it must update NoA etc.
 836                  */
 837                 if (ieee80211_vif_type_p2p(&sdata->vif) ==
 838                                 NL80211_IFTYPE_P2P_GO)
 839                         return -EOPNOTSUPP;
 840                 hw_scan = false;
 841                 goto again;
 842         }
 843
 844         return rc;
 845 }
 846
 847 static unsigned long
 848 ieee80211_scan_get_channel_time(struct ieee80211_channel *chan)
 849 {
 850         /*
 851          * TODO: channel switching also consumes quite some time,
 852          * add that delay as well to get a better estimation
 853          */
 854         if (chan->flags & (IEEE80211_CHAN_NO_IR | IEEE80211_CHAN_RADAR))
 855                 return IEEE80211_PASSIVE_CHANNEL_TIME;
 856         return IEEE80211_PROBE_DELAY + IEEE80211_CHANNEL_TIME;
 857 }
 858
 859 static void ieee80211_scan_state_decision(struct ieee80211_local *local,
 860                                           unsigned long *next_delay)
 861 {
 862         bool associated = false;
 863         bool tx_empty = true;
 864         bool bad_latency;
 865         struct ieee80211_sub_if_data *sdata;
 866         struct ieee80211_channel *next_chan;
 867         enum mac80211_scan_state next_scan_state;
 868         struct cfg80211_scan_request *scan_req;
 869
 870         /*
 871          * check if at least one STA interface is associated,
 872          * check if at least one STA interface has pending tx frames
 873          * and grab the lowest used beacon interval
 874          */
 875         mutex_lock(&local->iflist_mtx);
 876         list_for_each_entry(sdata, &local->interfaces, list) {
 877                 if (!ieee80211_sdata_running(sdata))
 878                         continue;
 879
 880                 if (sdata->vif.type == NL80211_IFTYPE_STATION) {
 881                         if (sdata->u.mgd.associated) {
 882                                 associated = true;
 883
 884                                 if (!qdisc_all_tx_empty(sdata->dev)) {
 885                                         tx_empty = false;
 886                                         break;
 887                                 }
 888                         }
 889                 }
 890         }
 891         mutex_unlock(&local->iflist_mtx);
 892
 893         scan_req = rcu_dereference_protected(local->scan_req,
 894                                              lockdep_is_held(&local->mtx));
 895
 896         next_chan = scan_req->channels[local->scan_channel_idx];
 897
 898         /*
 899          * we're currently scanning a different channel, let's
 900          * see if we can scan another channel without interfering
 901          * with the current traffic situation.
 902          *
 903          * Keep good latency, do not stay off-channel more than 125 ms.
 904          */
 905
 906         bad_latency = time_after(jiffies +
 907                                  ieee80211_scan_get_channel_time(next_chan),
 908                                  local->leave_oper_channel_time + HZ / 8);
 909
 910         if (associated && !tx_empty) {
 911                 if (scan_req->flags & NL80211_SCAN_FLAG_LOW_PRIORITY)
 912                         next_scan_state = SCAN_ABORT;
 913                 else
 914                         next_scan_state = SCAN_SUSPEND;
 915         } else if (associated && bad_latency) {
 916                 next_scan_state = SCAN_SUSPEND;
 917         } else {
 918                 next_scan_state = SCAN_SET_CHANNEL;
 919         }
 920
 921         local->next_scan_state = next_scan_state;
 922
 923         *next_delay = 0;
 924 }
 925
 926 static void ieee80211_scan_state_set_channel(struct ieee80211_local *local,
 927                                              unsigned long *next_delay)
 928 {
 929         int skip;
 930         struct ieee80211_channel *chan;
 931         enum nl80211_bss_scan_width oper_scan_width;
 932         struct cfg80211_scan_request *scan_req;
 933
 934         scan_req = rcu_dereference_protected(local->scan_req,
 935                                              lockdep_is_held(&local->mtx));
 936
 937         skip = 0;
 938         chan = scan_req->channels[local->scan_channel_idx];
 939
 940         local->scan_chandef.chan = chan;
 941         local->scan_chandef.center_freq1 = chan->center_freq;
 942         local->scan_chandef.freq1_offset = chan->freq_offset;
 943         local->scan_chandef.center_freq2 = 0;
 944
 945         /* For scanning on the S1G band, ignore scan_width (which is constant
 946          * across all channels) for now since channel width is specific to each
 947          * channel. Detect the required channel width here and likely revisit
 948          * later. Maybe scan_width could be used to build the channel scan list?
 949          */
 950         if (chan->band == NL80211_BAND_S1GHZ) {
 951                 local->scan_chandef.width = ieee80211_s1g_channel_width(chan);
 952                 goto set_channel;
 953         }
 954
 955         switch (scan_req->scan_width) {
 956         case NL80211_BSS_CHAN_WIDTH_5:
 957                 local->scan_chandef.width = NL80211_CHAN_WIDTH_5;
 958                 break;
 959         case NL80211_BSS_CHAN_WIDTH_10:
 960                 local->scan_chandef.width = NL80211_CHAN_WIDTH_10;
 961                 break;
 962         default:
 963         case NL80211_BSS_CHAN_WIDTH_20:
 964                 /* If scanning on oper channel, use whatever channel-type
 965                  * is currently in use.
 966                  */
 967                 oper_scan_width = cfg80211_chandef_to_scan_width(
 968                                         &local->_oper_chandef);
 969                 if (chan == local->_oper_chandef.chan &&
 970                     oper_scan_width == scan_req->scan_width)
 971                         local->scan_chandef = local->_oper_chandef;
 972                 else
 973                         local->scan_chandef.width = NL80211_CHAN_WIDTH_20_NOHT;
 974                 break;
 975         case NL80211_BSS_CHAN_WIDTH_1:
 976         case NL80211_BSS_CHAN_WIDTH_2:
 977                 /* shouldn't get here, S1G handled above */
 978                 WARN_ON(1);
 979                 break;
 980         }
 981
 982 set_channel:
 983         if (ieee80211_hw_config(local, IEEE80211_CONF_CHANGE_CHANNEL))
 984                 skip = 1;
 985
 986         /* advance state machine to next channel/band */
 987         local->scan_channel_idx++;
 988
 989         if (skip) {
 990                 /* if we skip this channel return to the decision state */
 991                 local->next_scan_state = SCAN_DECISION;
 992                 return;
 993         }
 994
 995         /*
 996          * Probe delay is used to update the NAV, cf. 11.1.3.2.2
 997          * (which unfortunately doesn't say _why_ step a) is done,
 998          * but it waits for the probe delay or until a frame is
 999          * received - and the received frame would update the NAV).
1000          * For now, we do not support waiting until a frame is
1001          * received.
1002          *
1003          * In any case, it is not necessary for a passive scan.
1004          */
1005         if ((chan->flags & (IEEE80211_CHAN_NO_IR | IEEE80211_CHAN_RADAR)) ||
1006             !scan_req->n_ssids) {
1007                 *next_delay = IEEE80211_PASSIVE_CHANNEL_TIME;
1008                 local->next_scan_state = SCAN_DECISION;
1009                 if (scan_req->n_ssids)
1010                         set_bit(SCAN_BEACON_WAIT, &local->scanning);
1011                 return;
1012         }
1013
1014         /* active scan, send probes */
1015         *next_delay = IEEE80211_PROBE_DELAY;
1016         local->next_scan_state = SCAN_SEND_PROBE;
1017 }
1018
1019 static void ieee80211_scan_state_suspend(struct ieee80211_local *local,
1020                                          unsigned long *next_delay)
1021 {
1022         /* switch back to the operating channel */
1023         local->scan_chandef.chan = NULL;
1024         ieee80211_hw_config(local, IEEE80211_CONF_CHANGE_CHANNEL);
1025
1026         /* disable PS */
1027         ieee80211_offchannel_return(local);
1028
1029         *next_delay = HZ / 5;
1030         /* afterwards, resume scan & go to next channel */
1031         local->next_scan_state = SCAN_RESUME;
1032 }
1033
1034 static void ieee80211_scan_state_resume(struct ieee80211_local *local,
1035                                         unsigned long *next_delay)
1036 {
1037         ieee80211_offchannel_stop_vifs(local);
1038
1039         if (local->ops->flush) {
1040                 ieee80211_flush_queues(local, NULL, false);
1041                 *next_delay = 0;
1042         } else
1043                 *next_delay = HZ / 10;
1044
1045         /* remember when we left the operating channel */
1046         local->leave_oper_channel_time = jiffies;
1047
1048         /* advance to the next channel to be scanned */
1049         local->next_scan_state = SCAN_SET_CHANNEL;
1050 }
1051
1052 void ieee80211_scan_work(struct work_struct *work)
1053 {
1054         struct ieee80211_local *local =
1055                 container_of(work, struct ieee80211_local, scan_work.work);
1056         struct ieee80211_sub_if_data *sdata;
1057         struct cfg80211_scan_request *scan_req;
1058         unsigned long next_delay = 0;
1059         bool aborted;
1060
1061         mutex_lock(&local->mtx);
1062
1063         if (!ieee80211_can_run_worker(local)) {
1064                 aborted = true;
1065                 goto out_complete;
1066         }
1067
1068         sdata = rcu_dereference_protected(local->scan_sdata,
1069                                           lockdep_is_held(&local->mtx));
1070         scan_req = rcu_dereference_protected(local->scan_req,
1071                                              lockdep_is_held(&local->mtx));
1072
1073         /* When scanning on-channel, the first-callback means completed. */
1074         if (test_bit(SCAN_ONCHANNEL_SCANNING, &local->scanning)) {
1075                 aborted = test_and_clear_bit(SCAN_ABORTED, &local->scanning);
1076                 goto out_complete;
1077         }
1078
1079         if (test_and_clear_bit(SCAN_COMPLETED, &local->scanning)) {
1080                 aborted = test_and_clear_bit(SCAN_ABORTED, &local->scanning);
1081                 goto out_complete;
1082         }
1083
1084         if (!sdata || !scan_req)
1085                 goto out;
1086
1087         if (!local->scanning) {
1088                 int rc;
1089
1090                 RCU_INIT_POINTER(local->scan_req, NULL);
1091                 RCU_INIT_POINTER(local->scan_sdata, NULL);
1092
1093                 rc = __ieee80211_start_scan(sdata, scan_req);
1094                 if (rc) {
1095                         /* need to complete scan in cfg80211 */
1096                         rcu_assign_pointer(local->scan_req, scan_req);
1097                         aborted = true;
1098                         goto out_complete;
1099                 } else
1100                         goto out;
1101         }
1102
1103         clear_bit(SCAN_BEACON_WAIT, &local->scanning);
1104
1105         /*
1106          * as long as no delay is required advance immediately
1107          * without scheduling a new work
1108          */
1109         do {
1110                 if (!ieee80211_sdata_running(sdata)) {
1111                         aborted = true;
1112                         goto out_complete;
1113                 }
1114
1115                 if (test_and_clear_bit(SCAN_BEACON_DONE, &local->scanning) &&
1116                     local->next_scan_state == SCAN_DECISION)
1117                         local->next_scan_state = SCAN_SEND_PROBE;
1118
1119                 switch (local->next_scan_state) {
1120                 case SCAN_DECISION:
1121                         /* if no more bands/channels left, complete scan */
1122                         if (local->scan_channel_idx >= scan_req->n_channels) {
1123                                 aborted = false;
1124                                 goto out_complete;
1125                         }
1126                         ieee80211_scan_state_decision(local, &next_delay);
1127                         break;
1128                 case SCAN_SET_CHANNEL:
1129                         ieee80211_scan_state_set_channel(local, &next_delay);
1130                         break;
1131                 case SCAN_SEND_PROBE:
1132                         ieee80211_scan_state_send_probe(local, &next_delay);
1133                         break;
1134                 case SCAN_SUSPEND:
1135                         ieee80211_scan_state_suspend(local, &next_delay);
1136                         break;
1137                 case SCAN_RESUME:
1138                         ieee80211_scan_state_resume(local, &next_delay);
1139                         break;
1140                 case SCAN_ABORT:
1141                         aborted = true;
1142                         goto out_complete;
1143                 }
1144         } while (next_delay == 0);
1145
1146         ieee80211_queue_delayed_work(&local->hw, &local->scan_work, next_delay);
1147         goto out;
1148
1149 out_complete:
1150         __ieee80211_scan_completed(&local->hw, aborted);
1151 out:
1152         mutex_unlock(&local->mtx);
1153 }
1154
1155 int ieee80211_request_scan(struct ieee80211_sub_if_data *sdata,
1156                            struct cfg80211_scan_request *req)
1157 {
1158         int res;
1159
1160         mutex_lock(&sdata->local->mtx);
1161         res = __ieee80211_start_scan(sdata, req);
1162         mutex_unlock(&sdata->local->mtx);
1163
1164         return res;
1165 }
1166
1167 int ieee80211_request_ibss_scan(struct ieee80211_sub_if_data *sdata,
1168                                 const u8 *ssid, u8 ssid_len,
1169                                 struct ieee80211_channel **channels,
1170                                 unsigned int n_channels,
1171                                 enum nl80211_bss_scan_width scan_width)
1172 {
1173         struct ieee80211_local *local = sdata->local;
1174         int ret = -EBUSY, i, n_ch = 0;
1175         enum nl80211_band band;
1176
1177         mutex_lock(&local->mtx);
1178
1179         /* busy scanning */
1180         if (local->scan_req)
1181                 goto unlock;
1182
1183         /* fill internal scan request */
1184         if (!channels) {
1185                 int max_n;
1186
1187                 for (band = 0; band < NUM_NL80211_BANDS; band++) {
1188                         if (!local->hw.wiphy->bands[band] ||
1189                             band == NL80211_BAND_6GHZ)
1190                                 continue;
1191
1192                         max_n = local->hw.wiphy->bands[band]->n_channels;
1193                         for (i = 0; i < max_n; i++) {
1194                                 struct ieee80211_channel *tmp_ch =
1195                                     &local->hw.wiphy->bands[band]->channels[i];
1196
1197                                 if (tmp_ch->flags & (IEEE80211_CHAN_NO_IR |
1198                                                      IEEE80211_CHAN_DISABLED))
1199                                         continue;
1200
1201                                 local->int_scan_req->channels[n_ch] = tmp_ch;
1202                                 n_ch++;
1203                         }
1204                 }
1205
1206                 if (WARN_ON_ONCE(n_ch == 0))
1207                         goto unlock;
1208
1209                 local->int_scan_req->n_channels = n_ch;
1210         } else {
1211                 for (i = 0; i < n_channels; i++) {
1212                         if (channels[i]->flags & (IEEE80211_CHAN_NO_IR |
1213                                                   IEEE80211_CHAN_DISABLED))
1214                                 continue;
1215
1216                         local->int_scan_req->channels[n_ch] = channels[i];
1217                         n_ch++;
1218                 }
1219
1220                 if (WARN_ON_ONCE(n_ch == 0))
1221                         goto unlock;
1222
1223                 local->int_scan_req->n_channels = n_ch;
1224         }
1225
1226         local->int_scan_req->ssids = &local->scan_ssid;
1227         local->int_scan_req->n_ssids = 1;
1228         local->int_scan_req->scan_width = scan_width;
1229         memcpy(local->int_scan_req->ssids[0].ssid, ssid, IEEE80211_MAX_SSID_LEN);
1230         local->int_scan_req->ssids[0].ssid_len = ssid_len;
1231
1232         ret = __ieee80211_start_scan(sdata, sdata->local->int_scan_req);
1233  unlock:
1234         mutex_unlock(&local->mtx);
1235         return ret;
1236 }
1237
1238 /*
1239  * Only call this function when a scan can't be queued -- under RTNL.
1240  */
1241 void ieee80211_scan_cancel(struct ieee80211_local *local)
1242 {
1243         /*
1244          * We are canceling software scan, or deferred scan that was not
1245          * yet really started (see __ieee80211_start_scan ).
1246          *
1247          * Regarding hardware scan:
1248          * - we can not call  __ieee80211_scan_completed() as when
1249          *   SCAN_HW_SCANNING bit is set this function change
1250          *   local->hw_scan_req to operate on 5G band, what race with
1251          *   driver which can use local->hw_scan_req
1252          *
1253          * - we can not cancel scan_work since driver can schedule it
1254          *   by ieee80211_scan_completed(..., true) to finish scan
1255          *
1256          * Hence we only call the cancel_hw_scan() callback, but the low-level
1257          * driver is still responsible for calling ieee80211_scan_completed()
1258          * after the scan was completed/aborted.
1259          */
1260
1261         mutex_lock(&local->mtx);
1262         if (!local->scan_req)
1263                 goto out;
1264
1265         /*
1266          * We have a scan running and the driver already reported completion,
1267          * but the worker hasn't run yet or is stuck on the mutex - mark it as
1268          * cancelled.
1269          */
1270         if (test_bit(SCAN_HW_SCANNING, &local->scanning) &&
1271             test_bit(SCAN_COMPLETED, &local->scanning)) {
1272                 set_bit(SCAN_HW_CANCELLED, &local->scanning);
1273                 goto out;
1274         }
1275
1276         if (test_bit(SCAN_HW_SCANNING, &local->scanning)) {
1277                 /*
1278                  * Make sure that __ieee80211_scan_completed doesn't trigger a
1279                  * scan on another band.
1280                  */
1281                 set_bit(SCAN_HW_CANCELLED, &local->scanning);
1282                 if (local->ops->cancel_hw_scan)
1283                         drv_cancel_hw_scan(local,
1284                                 rcu_dereference_protected(local->scan_sdata,
1285                                                 lockdep_is_held(&local->mtx)));
1286                 goto out;
1287         }
1288
1289         /*
1290          * If the work is currently running, it must be blocked on
1291          * the mutex, but we'll set scan_sdata = NULL and it'll
1292          * simply exit once it acquires the mutex.
1293          */
1294         cancel_delayed_work(&local->scan_work);
1295         /* and clean up */
1296         memset(&local->scan_info, 0, sizeof(local->scan_info));
1297         __ieee80211_scan_completed(&local->hw, true);
1298 out:
1299         mutex_unlock(&local->mtx);
1300 }
1301
1302 int __ieee80211_request_sched_scan_start(struct ieee80211_sub_if_data *sdata,
1303                                         struct cfg80211_sched_scan_request *req)
1304 {
1305         struct ieee80211_local *local = sdata->local;
1306         struct ieee80211_scan_ies sched_scan_ies = {};
1307         struct cfg80211_chan_def chandef;
1308         int ret, i, iebufsz, num_bands = 0;
1309         u32 rate_masks[NUM_NL80211_BANDS] = {};
1310         u8 bands_used = 0;
1311         u8 *ie;
1312         u32 flags = 0;
1313
1314         iebufsz = local->scan_ies_len + req->ie_len;
1315
1316         lockdep_assert_held(&local->mtx);
1317
1318         if (!local->ops->sched_scan_start)
1319                 return -ENOTSUPP;
1320
1321         for (i = 0; i < NUM_NL80211_BANDS; i++) {
1322                 if (local->hw.wiphy->bands[i]) {
1323                         bands_used |= BIT(i);
1324                         rate_masks[i] = (u32) -1;
1325                         num_bands++;
1326                 }
1327         }
1328
1329         if (req->flags & NL80211_SCAN_FLAG_MIN_PREQ_CONTENT)
1330                 flags |= IEEE80211_PROBE_FLAG_MIN_CONTENT;
1331
1332         ie = kcalloc(iebufsz, num_bands, GFP_KERNEL);
1333         if (!ie) {
1334                 ret = -ENOMEM;
1335                 goto out;
1336         }
1337
1338         ieee80211_prepare_scan_chandef(&chandef, req->scan_width);
1339
1340         ieee80211_build_preq_ies(sdata, ie, num_bands * iebufsz,
1341                                  &sched_scan_ies, req->ie,
1342                                  req->ie_len, bands_used, rate_masks, &chandef,
1343                                  flags);
1344
1345         ret = drv_sched_scan_start(local, sdata, req, &sched_scan_ies);
1346         if (ret == 0) {
1347                 rcu_assign_pointer(local->sched_scan_sdata, sdata);
1348                 rcu_assign_pointer(local->sched_scan_req, req);
1349         }
1350
1351         kfree(ie);
1352
1353 out:
1354         if (ret) {
1355                 /* Clean in case of failure after HW restart or upon resume. */
1356                 RCU_INIT_POINTER(local->sched_scan_sdata, NULL);
1357                 RCU_INIT_POINTER(local->sched_scan_req, NULL);
1358         }
1359
1360         return ret;
1361 }
1362
1363 int ieee80211_request_sched_scan_start(struct ieee80211_sub_if_data *sdata,
1364                                        struct cfg80211_sched_scan_request *req)
1365 {
1366         struct ieee80211_local *local = sdata->local;
1367         int ret;
1368
1369         mutex_lock(&local->mtx);
1370
1371         if (rcu_access_pointer(local->sched_scan_sdata)) {
1372                 mutex_unlock(&local->mtx);
1373                 return -EBUSY;
1374         }
1375
1376         ret = __ieee80211_request_sched_scan_start(sdata, req);
1377
1378         mutex_unlock(&local->mtx);
1379         return ret;
1380 }
1381
1382 int ieee80211_request_sched_scan_stop(struct ieee80211_local *local)
1383 {
1384         struct ieee80211_sub_if_data *sched_scan_sdata;
1385         int ret = -ENOENT;
1386
1387         mutex_lock(&local->mtx);
1388
1389         if (!local->ops->sched_scan_stop) {
1390                 ret = -ENOTSUPP;
1391                 goto out;
1392         }
1393
1394         /* We don't want to restart sched scan anymore. */
1395         RCU_INIT_POINTER(local->sched_scan_req, NULL);
1396
1397         sched_scan_sdata = rcu_dereference_protected(local->sched_scan_sdata,
1398                                                 lockdep_is_held(&local->mtx));
1399         if (sched_scan_sdata) {
1400                 ret = drv_sched_scan_stop(local, sched_scan_sdata);
1401                 if (!ret)
1402                         RCU_INIT_POINTER(local->sched_scan_sdata, NULL);
1403         }
1404 out:
1405         mutex_unlock(&local->mtx);
1406
1407         return ret;
1408 }
1409
1410 void ieee80211_sched_scan_results(struct ieee80211_hw *hw)
1411 {
1412         struct ieee80211_local *local = hw_to_local(hw);
1413
1414         trace_api_sched_scan_results(local);
1415
1416         cfg80211_sched_scan_results(hw->wiphy, 0);
1417 }
1418 EXPORT_SYMBOL(ieee80211_sched_scan_results);
1419
1420 void ieee80211_sched_scan_end(struct ieee80211_local *local)
1421 {
1422         mutex_lock(&local->mtx);
1423
1424         if (!rcu_access_pointer(local->sched_scan_sdata)) {
1425                 mutex_unlock(&local->mtx);
1426                 return;
1427         }
1428
1429         RCU_INIT_POINTER(local->sched_scan_sdata, NULL);
1430
1431         /* If sched scan was aborted by the driver. */
1432         RCU_INIT_POINTER(local->sched_scan_req, NULL);
1433
1434         mutex_unlock(&local->mtx);
1435
1436         cfg80211_sched_scan_stopped(local->hw.wiphy, 0);
1437 }
1438
1439 void ieee80211_sched_scan_stopped_work(struct work_struct *work)
1440 {
1441         struct ieee80211_local *local =
1442                 container_of(work, struct ieee80211_local,
1443                              sched_scan_stopped_work);
1444
1445         ieee80211_sched_scan_end(local);
1446 }
1447
1448 void ieee80211_sched_scan_stopped(struct ieee80211_hw *hw)
1449 {
1450         struct ieee80211_local *local = hw_to_local(hw);
1451
1452         trace_api_sched_scan_stopped(local);
1453
1454         /*
1455          * this shouldn't really happen, so for simplicity
1456          * simply ignore it, and let mac80211 reconfigure
1457          * the sched scan later on.
1458          */
1459         if (local->in_reconfig)
1460                 return;
1461
1462         schedule_work(&local->sched_scan_stopped_work);
1463 }
1464 EXPORT_SYMBOL(ieee80211_sched_scan_stopped);