net/mac80211/scan.c

   1 /*
   2  * Scanning implementation
   3  *
   4  * Copyright 2003, Jouni Malinen <jkmaline@cc.hut.fi>
   5  * Copyright 2004, Instant802 Networks, Inc.
   6  * Copyright 2005, Devicescape Software, Inc.
   7  * Copyright 2006-2007  Jiri Benc <jbenc@suse.cz>
   8  * Copyright 2007, Michael Wu <flamingice@sourmilk.net>
   9  * Copyright 2013-2015  Intel Mobile Communications GmbH
  10  *
  11  * This program is free software; you can redistribute it and/or modify
  12  * it under the terms of the GNU General Public License version 2 as
  13  * published by the Free Software Foundation.
  14  */
  15
  16 #include <linux/if_arp.h>
  17 #include <linux/etherdevice.h>
  18 #include <linux/rtnetlink.h>
  19 #include <net/sch_generic.h>
  20 #include <linux/slab.h>
  21 #include <linux/export.h>
  22 #include <net/mac80211.h>
  23
  24 #include "ieee80211_i.h"
  25 #include "driver-ops.h"
  26 #include "mesh.h"
  27
  28 #define IEEE80211_PROBE_DELAY (HZ / 33)
  29 #define IEEE80211_CHANNEL_TIME (HZ / 33)
  30 #define IEEE80211_PASSIVE_CHANNEL_TIME (HZ / 9)
  31
  32 void ieee80211_rx_bss_put(struct ieee80211_local *local,
  33                           struct ieee80211_bss *bss)
  34 {
  35         if (!bss)
  36                 return;
  37         cfg80211_put_bss(local->hw.wiphy,
  38                          container_of((void *)bss, struct cfg80211_bss, priv));
  39 }
  40
  41 static bool is_uapsd_supported(struct ieee802_11_elems *elems)
  42 {
  43         u8 qos_info;
  44
  45         if (elems->wmm_info && elems->wmm_info_len == 7
  46             && elems->wmm_info[5] == 1)
  47                 qos_info = elems->wmm_info[6];
  48         else if (elems->wmm_param && elems->wmm_param_len == 24
  49                  && elems->wmm_param[5] == 1)
  50                 qos_info = elems->wmm_param[6];
  51         else
  52                 /* no valid wmm information or parameter element found */
  53                 return false;
  54
  55         return qos_info & IEEE80211_WMM_IE_AP_QOSINFO_UAPSD;
  56 }
  57
  58 struct ieee80211_bss *
  59 ieee80211_bss_info_update(struct ieee80211_local *local,
  60                           struct ieee80211_rx_status *rx_status,
  61                           struct ieee80211_mgmt *mgmt, size_t len,
  62                           struct ieee802_11_elems *elems,
  63                           struct ieee80211_channel *channel)
  64 {
  65         bool beacon = ieee80211_is_beacon(mgmt->frame_control);
  66         struct cfg80211_bss *cbss;
  67         struct ieee80211_bss *bss;
  68         int clen, srlen;
  69         struct cfg80211_inform_bss bss_meta = {
  70                 .boottime_ns = rx_status->boottime_ns,
  71         };
  72         bool signal_valid;
  73
  74         if (ieee80211_hw_check(&local->hw, SIGNAL_DBM))
  75                 bss_meta.signal = rx_status->signal * 100;
  76         else if (ieee80211_hw_check(&local->hw, SIGNAL_UNSPEC))
  77                 bss_meta.signal = (rx_status->signal * 100) / local->hw.max_signal;
  78
  79         bss_meta.scan_width = NL80211_BSS_CHAN_WIDTH_20;
  80         if (rx_status->flag & RX_FLAG_5MHZ)
  81                 bss_meta.scan_width = NL80211_BSS_CHAN_WIDTH_5;
  82         if (rx_status->flag & RX_FLAG_10MHZ)
  83                 bss_meta.scan_width = NL80211_BSS_CHAN_WIDTH_10;
  84
  85         bss_meta.chan = channel;
  86         cbss = cfg80211_inform_bss_frame_data(local->hw.wiphy, &bss_meta,
  87                                               mgmt, len, GFP_ATOMIC);
  88         if (!cbss)
  89                 return NULL;
  90         /* In case the signal is invalid update the status */
  91         signal_valid = abs(channel->center_freq - cbss->channel->center_freq)
  92                 <= local->hw.wiphy->max_adj_channel_rssi_comp;
  93         if (!signal_valid)
  94                 rx_status->flag |= RX_FLAG_NO_SIGNAL_VAL;
  95
  96         bss = (void *)cbss->priv;
  97
  98         if (beacon)
  99                 bss->device_ts_beacon = rx_status->device_timestamp;
 100         else
 101                 bss->device_ts_presp = rx_status->device_timestamp;
 102
 103         if (elems->parse_error) {
 104                 if (beacon)
 105                         bss->corrupt_data |= IEEE80211_BSS_CORRUPT_BEACON;
 106                 else
 107                         bss->corrupt_data |= IEEE80211_BSS_CORRUPT_PROBE_RESP;
 108         } else {
 109                 if (beacon)
 110                         bss->corrupt_data &= ~IEEE80211_BSS_CORRUPT_BEACON;
 111                 else
 112                         bss->corrupt_data &= ~IEEE80211_BSS_CORRUPT_PROBE_RESP;
 113         }
 114
 115         /* save the ERP value so that it is available at association time */
 116         if (elems->erp_info && (!elems->parse_error ||
 117                                 !(bss->valid_data & IEEE80211_BSS_VALID_ERP))) {
 118                 bss->erp_value = elems->erp_info[0];
 119                 bss->has_erp_value = true;
 120                 if (!elems->parse_error)
 121                         bss->valid_data |= IEEE80211_BSS_VALID_ERP;
 122         }
 123
 124         /* replace old supported rates if we get new values */
 125         if (!elems->parse_error ||
 126             !(bss->valid_data & IEEE80211_BSS_VALID_RATES)) {
 127                 srlen = 0;
 128                 if (elems->supp_rates) {
 129                         clen = IEEE80211_MAX_SUPP_RATES;
 130                         if (clen > elems->supp_rates_len)
 131                                 clen = elems->supp_rates_len;
 132                         memcpy(bss->supp_rates, elems->supp_rates, clen);
 133                         srlen += clen;
 134                 }
 135                 if (elems->ext_supp_rates) {
 136                         clen = IEEE80211_MAX_SUPP_RATES - srlen;
 137                         if (clen > elems->ext_supp_rates_len)
 138                                 clen = elems->ext_supp_rates_len;
 139                         memcpy(bss->supp_rates + srlen, elems->ext_supp_rates,
 140                                clen);
 141                         srlen += clen;
 142                 }
 143                 if (srlen) {
 144                         bss->supp_rates_len = srlen;
 145                         if (!elems->parse_error)
 146                                 bss->valid_data |= IEEE80211_BSS_VALID_RATES;
 147                 }
 148         }
 149
 150         if (!elems->parse_error ||
 151             !(bss->valid_data & IEEE80211_BSS_VALID_WMM)) {
 152                 bss->wmm_used = elems->wmm_param || elems->wmm_info;
 153                 bss->uapsd_supported = is_uapsd_supported(elems);
 154                 if (!elems->parse_error)
 155                         bss->valid_data |= IEEE80211_BSS_VALID_WMM;
 156         }
 157
 158         if (beacon) {
 159                 struct ieee80211_supported_band *sband =
 160                         local->hw.wiphy->bands[rx_status->band];
 161                 if (!(rx_status->flag & RX_FLAG_HT) &&
 162                     !(rx_status->flag & RX_FLAG_VHT))
 163                         bss->beacon_rate =
 164                                 &sband->bitrates[rx_status->rate_idx];
 165         }
 166
 167         return bss;
 168 }
 169
 170 void ieee80211_scan_rx(struct ieee80211_local *local, struct sk_buff *skb)
 171 {
 172         struct ieee80211_rx_status *rx_status = IEEE80211_SKB_RXCB(skb);
 173         struct ieee80211_sub_if_data *sdata1, *sdata2;
 174         struct ieee80211_mgmt *mgmt = (void *)skb->data;
 175         struct ieee80211_bss *bss;
 176         u8 *elements;
 177         struct ieee80211_channel *channel;
 178         size_t baselen;
 179         struct ieee802_11_elems elems;
 180
 181         if (skb->len < 24 ||
 182             (!ieee80211_is_probe_resp(mgmt->frame_control) &&
 183              !ieee80211_is_beacon(mgmt->frame_control)))
 184                 return;
 185
 186         sdata1 = rcu_dereference(local->scan_sdata);
 187         sdata2 = rcu_dereference(local->sched_scan_sdata);
 188
 189         if (likely(!sdata1 && !sdata2))
 190                 return;
 191
 192         if (ieee80211_is_probe_resp(mgmt->frame_control)) {
 193                 struct cfg80211_scan_request *scan_req;
 194                 struct cfg80211_sched_scan_request *sched_scan_req;
 195
 196                 scan_req = rcu_dereference(local->scan_req);
 197                 sched_scan_req = rcu_dereference(local->sched_scan_req);
 198
 199                 /* ignore ProbeResp to foreign address unless scanning
 200                  * with randomised address
 201                  */
 202                 if (!(sdata1 &&
 203                       (ether_addr_equal(mgmt->da, sdata1->vif.addr) ||
 204                        scan_req->flags & NL80211_SCAN_FLAG_RANDOM_ADDR)) &&
 205                     !(sdata2 &&
 206                       (ether_addr_equal(mgmt->da, sdata2->vif.addr) ||
 207                        sched_scan_req->flags & NL80211_SCAN_FLAG_RANDOM_ADDR)))
 208                         return;
 209
 210                 elements = mgmt->u.probe_resp.variable;
 211                 baselen = offsetof(struct ieee80211_mgmt, u.probe_resp.variable);
 212         } else {
 213                 baselen = offsetof(struct ieee80211_mgmt, u.beacon.variable);
 214                 elements = mgmt->u.beacon.variable;
 215         }
 216
 217         if (baselen > skb->len)
 218                 return;
 219
 220         ieee802_11_parse_elems(elements, skb->len - baselen, false, &elems);
 221
 222         channel = ieee80211_get_channel(local->hw.wiphy, rx_status->freq);
 223
 224         if (!channel || channel->flags & IEEE80211_CHAN_DISABLED)
 225                 return;
 226
 227         bss = ieee80211_bss_info_update(local, rx_status,
 228                                         mgmt, skb->len, &elems,
 229                                         channel);
 230         if (bss)
 231                 ieee80211_rx_bss_put(local, bss);
 232 }
 233
 234 static void
 235 ieee80211_prepare_scan_chandef(struct cfg80211_chan_def *chandef,
 236                                enum nl80211_bss_scan_width scan_width)
 237 {
 238         memset(chandef, 0, sizeof(*chandef));
 239         switch (scan_width) {
 240         case NL80211_BSS_CHAN_WIDTH_5:
 241                 chandef->width = NL80211_CHAN_WIDTH_5;
 242                 break;
 243         case NL80211_BSS_CHAN_WIDTH_10:
 244                 chandef->width = NL80211_CHAN_WIDTH_10;
 245                 break;
 246         default:
 247                 chandef->width = NL80211_CHAN_WIDTH_20_NOHT;
 248                 break;
 249         }
 250 }
 251
 252 /* return false if no more work */
 253 static bool ieee80211_prep_hw_scan(struct ieee80211_local *local)
 254 {
 255         struct cfg80211_scan_request *req;
 256         struct cfg80211_chan_def chandef;
 257         u8 bands_used = 0;
 258         int i, ielen, n_chans;
 259
 260         req = rcu_dereference_protected(local->scan_req,
 261                                         lockdep_is_held(&local->mtx));
 262
 263         if (test_bit(SCAN_HW_CANCELLED, &local->scanning))
 264                 return false;
 265
 266         if (ieee80211_hw_check(&local->hw, SINGLE_SCAN_ON_ALL_BANDS)) {
 267                 for (i = 0; i < req->n_channels; i++) {
 268                         local->hw_scan_req->req.channels[i] = req->channels[i];
 269                         bands_used |= BIT(req->channels[i]->band);
 270                 }
 271
 272                 n_chans = req->n_channels;
 273         } else {
 274                 do {
 275                         if (local->hw_scan_band == NUM_NL80211_BANDS)
 276                                 return false;
 277
 278                         n_chans = 0;
 279
 280                         for (i = 0; i < req->n_channels; i++) {
 281                                 if (req->channels[i]->band !=
 282                                     local->hw_scan_band)
 283                                         continue;
 284                                 local->hw_scan_req->req.channels[n_chans] =
 285                                                         req->channels[i];
 286                                 n_chans++;
 287                                 bands_used |= BIT(req->channels[i]->band);
 288                         }
 289
 290                         local->hw_scan_band++;
 291                 } while (!n_chans);
 292         }
 293
 294         local->hw_scan_req->req.n_channels = n_chans;
 295         ieee80211_prepare_scan_chandef(&chandef, req->scan_width);
 296
 297         ielen = ieee80211_build_preq_ies(local,
 298                                          (u8 *)local->hw_scan_req->req.ie,
 299                                          local->hw_scan_ies_bufsize,
 300                                          &local->hw_scan_req->ies,
 301                                          req->ie, req->ie_len,
 302                                          bands_used, req->rates, &chandef);
 303         local->hw_scan_req->req.ie_len = ielen;
 304         local->hw_scan_req->req.no_cck = req->no_cck;
 305         ether_addr_copy(local->hw_scan_req->req.mac_addr, req->mac_addr);
 306         ether_addr_copy(local->hw_scan_req->req.mac_addr_mask,
 307                         req->mac_addr_mask);
 308         ether_addr_copy(local->hw_scan_req->req.bssid, req->bssid);
 309
 310         return true;
 311 }
 312
 313 static void __ieee80211_scan_completed(struct ieee80211_hw *hw, bool aborted)
 314 {
 315         struct ieee80211_local *local = hw_to_local(hw);
 316         bool hw_scan = local->ops->hw_scan;
 317         bool was_scanning = local->scanning;
 318         struct cfg80211_scan_request *scan_req;
 319         struct ieee80211_sub_if_data *scan_sdata;
 320         struct ieee80211_sub_if_data *sdata;
 321
 322         lockdep_assert_held(&local->mtx);
 323
 324         /*
 325          * It's ok to abort a not-yet-running scan (that
 326          * we have one at all will be verified by checking
 327          * local->scan_req next), but not to complete it
 328          * successfully.
 329          */
 330         if (WARN_ON(!local->scanning && !aborted))
 331                 aborted = true;
 332
 333         if (WARN_ON(!local->scan_req))
 334                 return;
 335
 336         if (hw_scan && !aborted &&
 337             !ieee80211_hw_check(&local->hw, SINGLE_SCAN_ON_ALL_BANDS) &&
 338             ieee80211_prep_hw_scan(local)) {
 339                 int rc;
 340
 341                 rc = drv_hw_scan(local,
 342                         rcu_dereference_protected(local->scan_sdata,
 343                                                   lockdep_is_held(&local->mtx)),
 344                         local->hw_scan_req);
 345
 346                 if (rc == 0)
 347                         return;
 348         }
 349
 350         kfree(local->hw_scan_req);
 351         local->hw_scan_req = NULL;
 352
 353         scan_req = rcu_dereference_protected(local->scan_req,
 354                                              lockdep_is_held(&local->mtx));
 355
 356         if (scan_req != local->int_scan_req)
 357                 cfg80211_scan_done(scan_req, aborted);
 358         RCU_INIT_POINTER(local->scan_req, NULL);
 359
 360         scan_sdata = rcu_dereference_protected(local->scan_sdata,
 361                                                lockdep_is_held(&local->mtx));
 362         RCU_INIT_POINTER(local->scan_sdata, NULL);
 363
 364         local->scanning = 0;
 365         local->scan_chandef.chan = NULL;
 366
 367         /* Set power back to normal operating levels. */
 368         ieee80211_hw_config(local, 0);
 369
 370         if (!hw_scan) {
 371                 ieee80211_configure_filter(local);
 372                 drv_sw_scan_complete(local, scan_sdata);
 373                 ieee80211_offchannel_return(local);
 374         }
 375
 376         ieee80211_recalc_idle(local);
 377
 378         ieee80211_mlme_notify_scan_completed(local);
 379         ieee80211_ibss_notify_scan_completed(local);
 380
 381         /* Requeue all the work that might have been ignored while
 382          * the scan was in progress; if there was none this will
 383          * just be a no-op for the particular interface.
 384          */
 385         list_for_each_entry_rcu(sdata, &local->interfaces, list) {
 386                 if (ieee80211_sdata_running(sdata))
 387                         ieee80211_queue_work(&sdata->local->hw, &sdata->work);
 388         }
 389
 390         if (was_scanning)
 391                 ieee80211_start_next_roc(local);
 392 }
 393
 394 void ieee80211_scan_completed(struct ieee80211_hw *hw, bool aborted)
 395 {
 396         struct ieee80211_local *local = hw_to_local(hw);
 397
 398         trace_api_scan_completed(local, aborted);
 399
 400         set_bit(SCAN_COMPLETED, &local->scanning);
 401         if (aborted)
 402                 set_bit(SCAN_ABORTED, &local->scanning);
 403         ieee80211_queue_delayed_work(&local->hw, &local->scan_work, 0);
 404 }
 405 EXPORT_SYMBOL(ieee80211_scan_completed);
 406
 407 static int ieee80211_start_sw_scan(struct ieee80211_local *local,
 408                                    struct ieee80211_sub_if_data *sdata)
 409 {
 410         /* Software scan is not supported in multi-channel cases */
 411         if (local->use_chanctx)
 412                 return -EOPNOTSUPP;
 413
 414         /*
 415          * Hardware/driver doesn't support hw_scan, so use software
 416          * scanning instead. First send a nullfunc frame with power save
 417          * bit on so that AP will buffer the frames for us while we are not
 418          * listening, then send probe requests to each channel and wait for
 419          * the responses. After all channels are scanned, tune back to the
 420          * original channel and send a nullfunc frame with power save bit
 421          * off to trigger the AP to send us all the buffered frames.
 422          *
 423          * Note that while local->sw_scanning is true everything else but
 424          * nullfunc frames and probe requests will be dropped in
 425          * ieee80211_tx_h_check_assoc().
 426          */
 427         drv_sw_scan_start(local, sdata, local->scan_addr);
 428
 429         local->leave_oper_channel_time = jiffies;
 430         local->next_scan_state = SCAN_DECISION;
 431         local->scan_channel_idx = 0;
 432
 433         ieee80211_offchannel_stop_vifs(local);
 434
 435         /* ensure nullfunc is transmitted before leaving operating channel */
 436         ieee80211_flush_queues(local, NULL, false);
 437
 438         ieee80211_configure_filter(local);
 439
 440         /* We need to set power level at maximum rate for scanning. */
 441         ieee80211_hw_config(local, 0);
 442
 443         ieee80211_queue_delayed_work(&local->hw,
 444                                      &local->scan_work, 0);
 445
 446         return 0;
 447 }
 448
 449 static bool ieee80211_can_scan(struct ieee80211_local *local,
 450                                struct ieee80211_sub_if_data *sdata)
 451 {
 452         if (ieee80211_is_radar_required(local))
 453                 return false;
 454
 455         if (!list_empty(&local->roc_list))
 456                 return false;
 457
 458         if (sdata->vif.type == NL80211_IFTYPE_STATION &&
 459             sdata->u.mgd.flags & IEEE80211_STA_CONNECTION_POLL)
 460                 return false;
 461
 462         return true;
 463 }
 464
 465 void ieee80211_run_deferred_scan(struct ieee80211_local *local)
 466 {
 467         lockdep_assert_held(&local->mtx);
 468
 469         if (!local->scan_req || local->scanning)
 470                 return;
 471
 472         if (!ieee80211_can_scan(local,
 473                                 rcu_dereference_protected(
 474                                         local->scan_sdata,
 475                                         lockdep_is_held(&local->mtx))))
 476                 return;
 477
 478         ieee80211_queue_delayed_work(&local->hw, &local->scan_work,
 479                                      round_jiffies_relative(0));
 480 }
 481
 482 static void ieee80211_scan_state_send_probe(struct ieee80211_local *local,
 483                                             unsigned long *next_delay)
 484 {
 485         int i;
 486         struct ieee80211_sub_if_data *sdata;
 487         struct cfg80211_scan_request *scan_req;
 488         enum nl80211_band band = local->hw.conf.chandef.chan->band;
 489         u32 tx_flags;
 490
 491         scan_req = rcu_dereference_protected(local->scan_req,
 492                                              lockdep_is_held(&local->mtx));
 493
 494         tx_flags = IEEE80211_TX_INTFL_OFFCHAN_TX_OK;
 495         if (scan_req->no_cck)
 496                 tx_flags |= IEEE80211_TX_CTL_NO_CCK_RATE;
 497
 498         sdata = rcu_dereference_protected(local->scan_sdata,
 499                                           lockdep_is_held(&local->mtx));
 500
 501         for (i = 0; i < scan_req->n_ssids; i++)
 502                 ieee80211_send_probe_req(
 503                         sdata, local->scan_addr, scan_req->bssid,
 504                         scan_req->ssids[i].ssid, scan_req->ssids[i].ssid_len,
 505                         scan_req->ie, scan_req->ie_len,
 506                         scan_req->rates[band], false,
 507                         tx_flags, local->hw.conf.chandef.chan, true);
 508
 509         /*
 510          * After sending probe requests, wait for probe responses
 511          * on the channel.
 512          */
 513         *next_delay = IEEE80211_CHANNEL_TIME;
 514         local->next_scan_state = SCAN_DECISION;
 515 }
 516
 517 static int __ieee80211_start_scan(struct ieee80211_sub_if_data *sdata,
 518                                   struct cfg80211_scan_request *req)
 519 {
 520         struct ieee80211_local *local = sdata->local;
 521         int rc;
 522
 523         lockdep_assert_held(&local->mtx);
 524
 525         if (local->scan_req || ieee80211_is_radar_required(local))
 526                 return -EBUSY;
 527
 528         if (!ieee80211_can_scan(local, sdata)) {
 529                 /* wait for the work to finish/time out */
 530                 rcu_assign_pointer(local->scan_req, req);
 531                 rcu_assign_pointer(local->scan_sdata, sdata);
 532                 return 0;
 533         }
 534
 535         if (local->ops->hw_scan) {
 536                 u8 *ies;
 537
 538                 local->hw_scan_ies_bufsize = local->scan_ies_len + req->ie_len;
 539
 540                 if (ieee80211_hw_check(&local->hw, SINGLE_SCAN_ON_ALL_BANDS)) {
 541                         int i, n_bands = 0;
 542                         u8 bands_counted = 0;
 543
 544                         for (i = 0; i < req->n_channels; i++) {
 545                                 if (bands_counted & BIT(req->channels[i]->band))
 546                                         continue;
 547                                 bands_counted |= BIT(req->channels[i]->band);
 548                                 n_bands++;
 549                         }
 550
 551                         local->hw_scan_ies_bufsize *= n_bands;
 552                 }
 553
 554                 local->hw_scan_req = kmalloc(
 555                                 sizeof(*local->hw_scan_req) +
 556                                 req->n_channels * sizeof(req->channels[0]) +
 557                                 local->hw_scan_ies_bufsize, GFP_KERNEL);
 558                 if (!local->hw_scan_req)
 559                         return -ENOMEM;
 560
 561                 local->hw_scan_req->req.ssids = req->ssids;
 562                 local->hw_scan_req->req.n_ssids = req->n_ssids;
 563                 ies = (u8 *)local->hw_scan_req +
 564                         sizeof(*local->hw_scan_req) +
 565                         req->n_channels * sizeof(req->channels[0]);
 566                 local->hw_scan_req->req.ie = ies;
 567                 local->hw_scan_req->req.flags = req->flags;
 568                 eth_broadcast_addr(local->hw_scan_req->req.bssid);
 569
 570                 local->hw_scan_band = 0;
 571
 572                 /*
 573                  * After allocating local->hw_scan_req, we must
 574                  * go through until ieee80211_prep_hw_scan(), so
 575                  * anything that might be changed here and leave
 576                  * this function early must not go after this
 577                  * allocation.
 578                  */
 579         }
 580
 581         rcu_assign_pointer(local->scan_req, req);
 582         rcu_assign_pointer(local->scan_sdata, sdata);
 583
 584         if (req->flags & NL80211_SCAN_FLAG_RANDOM_ADDR)
 585                 get_random_mask_addr(local->scan_addr,
 586                                      req->mac_addr,
 587                                      req->mac_addr_mask);
 588         else
 589                 memcpy(local->scan_addr, sdata->vif.addr, ETH_ALEN);
 590
 591         if (local->ops->hw_scan) {
 592                 __set_bit(SCAN_HW_SCANNING, &local->scanning);
 593         } else if ((req->n_channels == 1) &&
 594                    (req->channels[0] == local->_oper_chandef.chan)) {
 595                 /*
 596                  * If we are scanning only on the operating channel
 597                  * then we do not need to stop normal activities
 598                  */
 599                 unsigned long next_delay;
 600
 601                 __set_bit(SCAN_ONCHANNEL_SCANNING, &local->scanning);
 602
 603                 ieee80211_recalc_idle(local);
 604
 605                 /* Notify driver scan is starting, keep order of operations
 606                  * same as normal software scan, in case that matters. */
 607                 drv_sw_scan_start(local, sdata, local->scan_addr);
 608
 609                 ieee80211_configure_filter(local); /* accept probe-responses */
 610
 611                 /* We need to ensure power level is at max for scanning. */
 612                 ieee80211_hw_config(local, 0);
 613
 614                 if ((req->channels[0]->flags & (IEEE80211_CHAN_NO_IR |
 615                                                 IEEE80211_CHAN_RADAR)) ||
 616                     !req->n_ssids) {
 617                         next_delay = IEEE80211_PASSIVE_CHANNEL_TIME;
 618                 } else {
 619                         ieee80211_scan_state_send_probe(local, &next_delay);
 620                         next_delay = IEEE80211_CHANNEL_TIME;
 621                 }
 622
 623                 /* Now, just wait a bit and we are all done! */
 624                 ieee80211_queue_delayed_work(&local->hw, &local->scan_work,
 625                                              next_delay);
 626                 return 0;
 627         } else {
 628                 /* Do normal software scan */
 629                 __set_bit(SCAN_SW_SCANNING, &local->scanning);
 630         }
 631
 632         ieee80211_recalc_idle(local);
 633
 634         if (local->ops->hw_scan) {
 635                 WARN_ON(!ieee80211_prep_hw_scan(local));
 636                 rc = drv_hw_scan(local, sdata, local->hw_scan_req);
 637         } else {
 638                 rc = ieee80211_start_sw_scan(local, sdata);
 639         }
 640
 641         if (rc) {
 642                 kfree(local->hw_scan_req);
 643                 local->hw_scan_req = NULL;
 644                 local->scanning = 0;
 645
 646                 ieee80211_recalc_idle(local);
 647
 648                 local->scan_req = NULL;
 649                 RCU_INIT_POINTER(local->scan_sdata, NULL);
 650         }
 651
 652         return rc;
 653 }
 654
 655 static unsigned long
 656 ieee80211_scan_get_channel_time(struct ieee80211_channel *chan)
 657 {
 658         /*
 659          * TODO: channel switching also consumes quite some time,
 660          * add that delay as well to get a better estimation
 661          */
 662         if (chan->flags & (IEEE80211_CHAN_NO_IR | IEEE80211_CHAN_RADAR))
 663                 return IEEE80211_PASSIVE_CHANNEL_TIME;
 664         return IEEE80211_PROBE_DELAY + IEEE80211_CHANNEL_TIME;
 665 }
 666
 667 static void ieee80211_scan_state_decision(struct ieee80211_local *local,
 668                                           unsigned long *next_delay)
 669 {
 670         bool associated = false;
 671         bool tx_empty = true;
 672         bool bad_latency;
 673         struct ieee80211_sub_if_data *sdata;
 674         struct ieee80211_channel *next_chan;
 675         enum mac80211_scan_state next_scan_state;
 676         struct cfg80211_scan_request *scan_req;
 677
 678         /*
 679          * check if at least one STA interface is associated,
 680          * check if at least one STA interface has pending tx frames
 681          * and grab the lowest used beacon interval
 682          */
 683         mutex_lock(&local->iflist_mtx);
 684         list_for_each_entry(sdata, &local->interfaces, list) {
 685                 if (!ieee80211_sdata_running(sdata))
 686                         continue;
 687
 688                 if (sdata->vif.type == NL80211_IFTYPE_STATION) {
 689                         if (sdata->u.mgd.associated) {
 690                                 associated = true;
 691
 692                                 if (!qdisc_all_tx_empty(sdata->dev)) {
 693                                         tx_empty = false;
 694                                         break;
 695                                 }
 696                         }
 697                 }
 698         }
 699         mutex_unlock(&local->iflist_mtx);
 700
 701         scan_req = rcu_dereference_protected(local->scan_req,
 702                                              lockdep_is_held(&local->mtx));
 703
 704         next_chan = scan_req->channels[local->scan_channel_idx];
 705
 706         /*
 707          * we're currently scanning a different channel, let's
 708          * see if we can scan another channel without interfering
 709          * with the current traffic situation.
 710          *
 711          * Keep good latency, do not stay off-channel more than 125 ms.
 712          */
 713
 714         bad_latency = time_after(jiffies +
 715                                  ieee80211_scan_get_channel_time(next_chan),
 716                                  local->leave_oper_channel_time + HZ / 8);
 717
 718         if (associated && !tx_empty) {
 719                 if (scan_req->flags & NL80211_SCAN_FLAG_LOW_PRIORITY)
 720                         next_scan_state = SCAN_ABORT;
 721                 else
 722                         next_scan_state = SCAN_SUSPEND;
 723         } else if (associated && bad_latency) {
 724                 next_scan_state = SCAN_SUSPEND;
 725         } else {
 726                 next_scan_state = SCAN_SET_CHANNEL;
 727         }
 728
 729         local->next_scan_state = next_scan_state;
 730
 731         *next_delay = 0;
 732 }
 733
 734 static void ieee80211_scan_state_set_channel(struct ieee80211_local *local,
 735                                              unsigned long *next_delay)
 736 {
 737         int skip;
 738         struct ieee80211_channel *chan;
 739         enum nl80211_bss_scan_width oper_scan_width;
 740         struct cfg80211_scan_request *scan_req;
 741
 742         scan_req = rcu_dereference_protected(local->scan_req,
 743                                              lockdep_is_held(&local->mtx));
 744
 745         skip = 0;
 746         chan = scan_req->channels[local->scan_channel_idx];
 747
 748         local->scan_chandef.chan = chan;
 749         local->scan_chandef.center_freq1 = chan->center_freq;
 750         local->scan_chandef.center_freq2 = 0;
 751         switch (scan_req->scan_width) {
 752         case NL80211_BSS_CHAN_WIDTH_5:
 753                 local->scan_chandef.width = NL80211_CHAN_WIDTH_5;
 754                 break;
 755         case NL80211_BSS_CHAN_WIDTH_10:
 756                 local->scan_chandef.width = NL80211_CHAN_WIDTH_10;
 757                 break;
 758         case NL80211_BSS_CHAN_WIDTH_20:
 759                 /* If scanning on oper channel, use whatever channel-type
 760                  * is currently in use.
 761                  */
 762                 oper_scan_width = cfg80211_chandef_to_scan_width(
 763                                         &local->_oper_chandef);
 764                 if (chan == local->_oper_chandef.chan &&
 765                     oper_scan_width == scan_req->scan_width)
 766                         local->scan_chandef = local->_oper_chandef;
 767                 else
 768                         local->scan_chandef.width = NL80211_CHAN_WIDTH_20_NOHT;
 769                 break;
 770         }
 771
 772         if (ieee80211_hw_config(local, IEEE80211_CONF_CHANGE_CHANNEL))
 773                 skip = 1;
 774
 775         /* advance state machine to next channel/band */
 776         local->scan_channel_idx++;
 777
 778         if (skip) {
 779                 /* if we skip this channel return to the decision state */
 780                 local->next_scan_state = SCAN_DECISION;
 781                 return;
 782         }
 783
 784         /*
 785          * Probe delay is used to update the NAV, cf. 11.1.3.2.2
 786          * (which unfortunately doesn't say _why_ step a) is done,
 787          * but it waits for the probe delay or until a frame is
 788          * received - and the received frame would update the NAV).
 789          * For now, we do not support waiting until a frame is
 790          * received.
 791          *
 792          * In any case, it is not necessary for a passive scan.
 793          */
 794         if ((chan->flags & (IEEE80211_CHAN_NO_IR | IEEE80211_CHAN_RADAR)) ||
 795             !scan_req->n_ssids) {
 796                 *next_delay = IEEE80211_PASSIVE_CHANNEL_TIME;
 797                 local->next_scan_state = SCAN_DECISION;
 798                 return;
 799         }
 800
 801         /* active scan, send probes */
 802         *next_delay = IEEE80211_PROBE_DELAY;
 803         local->next_scan_state = SCAN_SEND_PROBE;
 804 }
 805
 806 static void ieee80211_scan_state_suspend(struct ieee80211_local *local,
 807                                          unsigned long *next_delay)
 808 {
 809         /* switch back to the operating channel */
 810         local->scan_chandef.chan = NULL;
 811         ieee80211_hw_config(local, IEEE80211_CONF_CHANGE_CHANNEL);
 812
 813         /* disable PS */
 814         ieee80211_offchannel_return(local);
 815
 816         *next_delay = HZ / 5;
 817         /* afterwards, resume scan & go to next channel */
 818         local->next_scan_state = SCAN_RESUME;
 819 }
 820
 821 static void ieee80211_scan_state_resume(struct ieee80211_local *local,
 822                                         unsigned long *next_delay)
 823 {
 824         ieee80211_offchannel_stop_vifs(local);
 825
 826         if (local->ops->flush) {
 827                 ieee80211_flush_queues(local, NULL, false);
 828                 *next_delay = 0;
 829         } else
 830                 *next_delay = HZ / 10;
 831
 832         /* remember when we left the operating channel */
 833         local->leave_oper_channel_time = jiffies;
 834
 835         /* advance to the next channel to be scanned */
 836         local->next_scan_state = SCAN_SET_CHANNEL;
 837 }
 838
 839 void ieee80211_scan_work(struct work_struct *work)
 840 {
 841         struct ieee80211_local *local =
 842                 container_of(work, struct ieee80211_local, scan_work.work);
 843         struct ieee80211_sub_if_data *sdata;
 844         struct cfg80211_scan_request *scan_req;
 845         unsigned long next_delay = 0;
 846         bool aborted;
 847
 848         mutex_lock(&local->mtx);
 849
 850         if (!ieee80211_can_run_worker(local)) {
 851                 aborted = true;
 852                 goto out_complete;
 853         }
 854
 855         sdata = rcu_dereference_protected(local->scan_sdata,
 856                                           lockdep_is_held(&local->mtx));
 857         scan_req = rcu_dereference_protected(local->scan_req,
 858                                              lockdep_is_held(&local->mtx));
 859
 860         /* When scanning on-channel, the first-callback means completed. */
 861         if (test_bit(SCAN_ONCHANNEL_SCANNING, &local->scanning)) {
 862                 aborted = test_and_clear_bit(SCAN_ABORTED, &local->scanning);
 863                 goto out_complete;
 864         }
 865
 866         if (test_and_clear_bit(SCAN_COMPLETED, &local->scanning)) {
 867                 aborted = test_and_clear_bit(SCAN_ABORTED, &local->scanning);
 868                 goto out_complete;
 869         }
 870
 871         if (!sdata || !scan_req)
 872                 goto out;
 873
 874         if (!local->scanning) {
 875                 int rc;
 876
 877                 RCU_INIT_POINTER(local->scan_req, NULL);
 878                 RCU_INIT_POINTER(local->scan_sdata, NULL);
 879
 880                 rc = __ieee80211_start_scan(sdata, scan_req);
 881                 if (rc) {
 882                         /* need to complete scan in cfg80211 */
 883                         rcu_assign_pointer(local->scan_req, scan_req);
 884                         aborted = true;
 885                         goto out_complete;
 886                 } else
 887                         goto out;
 888         }
 889
 890         /*
 891          * as long as no delay is required advance immediately
 892          * without scheduling a new work
 893          */
 894         do {
 895                 if (!ieee80211_sdata_running(sdata)) {
 896                         aborted = true;
 897                         goto out_complete;
 898                 }
 899
 900                 switch (local->next_scan_state) {
 901                 case SCAN_DECISION:
 902                         /* if no more bands/channels left, complete scan */
 903                         if (local->scan_channel_idx >= scan_req->n_channels) {
 904                                 aborted = false;
 905                                 goto out_complete;
 906                         }
 907                         ieee80211_scan_state_decision(local, &next_delay);
 908                         break;
 909                 case SCAN_SET_CHANNEL:
 910                         ieee80211_scan_state_set_channel(local, &next_delay);
 911                         break;
 912                 case SCAN_SEND_PROBE:
 913                         ieee80211_scan_state_send_probe(local, &next_delay);
 914                         break;
 915                 case SCAN_SUSPEND:
 916                         ieee80211_scan_state_suspend(local, &next_delay);
 917                         break;
 918                 case SCAN_RESUME:
 919                         ieee80211_scan_state_resume(local, &next_delay);
 920                         break;
 921                 case SCAN_ABORT:
 922                         aborted = true;
 923                         goto out_complete;
 924                 }
 925         } while (next_delay == 0);
 926
 927         ieee80211_queue_delayed_work(&local->hw, &local->scan_work, next_delay);
 928         goto out;
 929
 930 out_complete:
 931         __ieee80211_scan_completed(&local->hw, aborted);
 932 out:
 933         mutex_unlock(&local->mtx);
 934 }
 935
 936 int ieee80211_request_scan(struct ieee80211_sub_if_data *sdata,
 937                            struct cfg80211_scan_request *req)
 938 {
 939         int res;
 940
 941         mutex_lock(&sdata->local->mtx);
 942         res = __ieee80211_start_scan(sdata, req);
 943         mutex_unlock(&sdata->local->mtx);
 944
 945         return res;
 946 }
 947
 948 int ieee80211_request_ibss_scan(struct ieee80211_sub_if_data *sdata,
 949                                 const u8 *ssid, u8 ssid_len,
 950                                 struct ieee80211_channel **channels,
 951                                 unsigned int n_channels,
 952                                 enum nl80211_bss_scan_width scan_width)
 953 {
 954         struct ieee80211_local *local = sdata->local;
 955         int ret = -EBUSY, i, n_ch = 0;
 956         enum nl80211_band band;
 957
 958         mutex_lock(&local->mtx);
 959
 960         /* busy scanning */
 961         if (local->scan_req)
 962                 goto unlock;
 963
 964         /* fill internal scan request */
 965         if (!channels) {
 966                 int max_n;
 967
 968                 for (band = 0; band < NUM_NL80211_BANDS; band++) {
 969                         if (!local->hw.wiphy->bands[band])
 970                                 continue;
 971
 972                         max_n = local->hw.wiphy->bands[band]->n_channels;
 973                         for (i = 0; i < max_n; i++) {
 974                                 struct ieee80211_channel *tmp_ch =
 975                                     &local->hw.wiphy->bands[band]->channels[i];
 976
 977                                 if (tmp_ch->flags & (IEEE80211_CHAN_NO_IR |
 978                                                      IEEE80211_CHAN_DISABLED))
 979                                         continue;
 980
 981                                 local->int_scan_req->channels[n_ch] = tmp_ch;
 982                                 n_ch++;
 983                         }
 984                 }
 985
 986                 if (WARN_ON_ONCE(n_ch == 0))
 987                         goto unlock;
 988
 989                 local->int_scan_req->n_channels = n_ch;
 990         } else {
 991                 for (i = 0; i < n_channels; i++) {
 992                         if (channels[i]->flags & (IEEE80211_CHAN_NO_IR |
 993                                                   IEEE80211_CHAN_DISABLED))
 994                                 continue;
 995
 996                         local->int_scan_req->channels[n_ch] = channels[i];
 997                         n_ch++;
 998                 }
 999
1000                 if (WARN_ON_ONCE(n_ch == 0))
1001                         goto unlock;
1002
1003                 local->int_scan_req->n_channels = n_ch;
1004         }
1005
1006         local->int_scan_req->ssids = &local->scan_ssid;
1007         local->int_scan_req->n_ssids = 1;
1008         local->int_scan_req->scan_width = scan_width;
1009         memcpy(local->int_scan_req->ssids[0].ssid, ssid, IEEE80211_MAX_SSID_LEN);
1010         local->int_scan_req->ssids[0].ssid_len = ssid_len;
1011
1012         ret = __ieee80211_start_scan(sdata, sdata->local->int_scan_req);
1013  unlock:
1014         mutex_unlock(&local->mtx);
1015         return ret;
1016 }
1017
1018 /*
1019  * Only call this function when a scan can't be queued -- under RTNL.
1020  */
1021 void ieee80211_scan_cancel(struct ieee80211_local *local)
1022 {
1023         /*
1024          * We are canceling software scan, or deferred scan that was not
1025          * yet really started (see __ieee80211_start_scan ).
1026          *
1027          * Regarding hardware scan:
1028          * - we can not call  __ieee80211_scan_completed() as when
1029          *   SCAN_HW_SCANNING bit is set this function change
1030          *   local->hw_scan_req to operate on 5G band, what race with
1031          *   driver which can use local->hw_scan_req
1032          *
1033          * - we can not cancel scan_work since driver can schedule it
1034          *   by ieee80211_scan_completed(..., true) to finish scan
1035          *
1036          * Hence we only call the cancel_hw_scan() callback, but the low-level
1037          * driver is still responsible for calling ieee80211_scan_completed()
1038          * after the scan was completed/aborted.
1039          */
1040
1041         mutex_lock(&local->mtx);
1042         if (!local->scan_req)
1043                 goto out;
1044
1045         /*
1046          * We have a scan running and the driver already reported completion,
1047          * but the worker hasn't run yet or is stuck on the mutex - mark it as
1048          * cancelled.
1049          */
1050         if (test_bit(SCAN_HW_SCANNING, &local->scanning) &&
1051             test_bit(SCAN_COMPLETED, &local->scanning)) {
1052                 set_bit(SCAN_HW_CANCELLED, &local->scanning);
1053                 goto out;
1054         }
1055
1056         if (test_bit(SCAN_HW_SCANNING, &local->scanning)) {
1057                 /*
1058                  * Make sure that __ieee80211_scan_completed doesn't trigger a
1059                  * scan on another band.
1060                  */
1061                 set_bit(SCAN_HW_CANCELLED, &local->scanning);
1062                 if (local->ops->cancel_hw_scan)
1063                         drv_cancel_hw_scan(local,
1064                                 rcu_dereference_protected(local->scan_sdata,
1065                                                 lockdep_is_held(&local->mtx)));
1066                 goto out;
1067         }
1068
1069         /*
1070          * If the work is currently running, it must be blocked on
1071          * the mutex, but we'll set scan_sdata = NULL and it'll
1072          * simply exit once it acquires the mutex.
1073          */
1074         cancel_delayed_work(&local->scan_work);
1075         /* and clean up */
1076         __ieee80211_scan_completed(&local->hw, true);
1077 out:
1078         mutex_unlock(&local->mtx);
1079 }
1080
1081 int __ieee80211_request_sched_scan_start(struct ieee80211_sub_if_data *sdata,
1082                                         struct cfg80211_sched_scan_request *req)
1083 {
1084         struct ieee80211_local *local = sdata->local;
1085         struct ieee80211_scan_ies sched_scan_ies = {};
1086         struct cfg80211_chan_def chandef;
1087         int ret, i, iebufsz, num_bands = 0;
1088         u32 rate_masks[NUM_NL80211_BANDS] = {};
1089         u8 bands_used = 0;
1090         u8 *ie;
1091         size_t len;
1092
1093         iebufsz = local->scan_ies_len + req->ie_len;
1094
1095         lockdep_assert_held(&local->mtx);
1096
1097         if (!local->ops->sched_scan_start)
1098                 return -ENOTSUPP;
1099
1100         for (i = 0; i < NUM_NL80211_BANDS; i++) {
1101                 if (local->hw.wiphy->bands[i]) {
1102                         bands_used |= BIT(i);
1103                         rate_masks[i] = (u32) -1;
1104                         num_bands++;
1105                 }
1106         }
1107
1108         ie = kzalloc(num_bands * iebufsz, GFP_KERNEL);
1109         if (!ie) {
1110                 ret = -ENOMEM;
1111                 goto out;
1112         }
1113
1114         ieee80211_prepare_scan_chandef(&chandef, req->scan_width);
1115
1116         len = ieee80211_build_preq_ies(local, ie, num_bands * iebufsz,
1117                                        &sched_scan_ies, req->ie,
1118                                        req->ie_len, bands_used,
1119                                        rate_masks, &chandef);
1120
1121         ret = drv_sched_scan_start(local, sdata, req, &sched_scan_ies);
1122         if (ret == 0) {
1123                 rcu_assign_pointer(local->sched_scan_sdata, sdata);
1124                 rcu_assign_pointer(local->sched_scan_req, req);
1125         }
1126
1127         kfree(ie);
1128
1129 out:
1130         if (ret) {
1131                 /* Clean in case of failure after HW restart or upon resume. */
1132                 RCU_INIT_POINTER(local->sched_scan_sdata, NULL);
1133                 RCU_INIT_POINTER(local->sched_scan_req, NULL);
1134         }
1135
1136         return ret;
1137 }
1138
1139 int ieee80211_request_sched_scan_start(struct ieee80211_sub_if_data *sdata,
1140                                        struct cfg80211_sched_scan_request *req)
1141 {
1142         struct ieee80211_local *local = sdata->local;
1143         int ret;
1144
1145         mutex_lock(&local->mtx);
1146
1147         if (rcu_access_pointer(local->sched_scan_sdata)) {
1148                 mutex_unlock(&local->mtx);
1149                 return -EBUSY;
1150         }
1151
1152         ret = __ieee80211_request_sched_scan_start(sdata, req);
1153
1154         mutex_unlock(&local->mtx);
1155         return ret;
1156 }
1157
1158 int ieee80211_request_sched_scan_stop(struct ieee80211_local *local)
1159 {
1160         struct ieee80211_sub_if_data *sched_scan_sdata;
1161         int ret = -ENOENT;
1162
1163         mutex_lock(&local->mtx);
1164
1165         if (!local->ops->sched_scan_stop) {
1166                 ret = -ENOTSUPP;
1167                 goto out;
1168         }
1169
1170         /* We don't want to restart sched scan anymore. */
1171         RCU_INIT_POINTER(local->sched_scan_req, NULL);
1172
1173         sched_scan_sdata = rcu_dereference_protected(local->sched_scan_sdata,
1174                                                 lockdep_is_held(&local->mtx));
1175         if (sched_scan_sdata) {
1176                 ret = drv_sched_scan_stop(local, sched_scan_sdata);
1177                 if (!ret)
1178                         RCU_INIT_POINTER(local->sched_scan_sdata, NULL);
1179         }
1180 out:
1181         mutex_unlock(&local->mtx);
1182
1183         return ret;
1184 }
1185
1186 void ieee80211_sched_scan_results(struct ieee80211_hw *hw)
1187 {
1188         struct ieee80211_local *local = hw_to_local(hw);
1189
1190         trace_api_sched_scan_results(local);
1191
1192         cfg80211_sched_scan_results(hw->wiphy);
1193 }
1194 EXPORT_SYMBOL(ieee80211_sched_scan_results);
1195
1196 void ieee80211_sched_scan_end(struct ieee80211_local *local)
1197 {
1198         mutex_lock(&local->mtx);
1199
1200         if (!rcu_access_pointer(local->sched_scan_sdata)) {
1201                 mutex_unlock(&local->mtx);
1202                 return;
1203         }
1204
1205         RCU_INIT_POINTER(local->sched_scan_sdata, NULL);
1206
1207         /* If sched scan was aborted by the driver. */
1208         RCU_INIT_POINTER(local->sched_scan_req, NULL);
1209
1210         mutex_unlock(&local->mtx);
1211
1212         cfg80211_sched_scan_stopped(local->hw.wiphy);
1213 }
1214
1215 void ieee80211_sched_scan_stopped_work(struct work_struct *work)
1216 {
1217         struct ieee80211_local *local =
1218                 container_of(work, struct ieee80211_local,
1219                              sched_scan_stopped_work);
1220
1221         ieee80211_sched_scan_end(local);
1222 }
1223
1224 void ieee80211_sched_scan_stopped(struct ieee80211_hw *hw)
1225 {
1226         struct ieee80211_local *local = hw_to_local(hw);
1227
1228         trace_api_sched_scan_stopped(local);
1229
1230         /*
1231          * this shouldn't really happen, so for simplicity
1232          * simply ignore it, and let mac80211 reconfigure
1233          * the sched scan later on.
1234          */
1235         if (local->in_reconfig)
1236                 return;
1237
1238         schedule_work(&local->sched_scan_stopped_work);
1239 }
1240 EXPORT_SYMBOL(ieee80211_sched_scan_stopped);