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 2013-2014  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 <linux/pm_qos.h>
  20 #include <net/sch_generic.h>
  21 #include <linux/slab.h>
  22 #include <linux/export.h>
  23 #include <net/mac80211.h>
  24
  25 #include "ieee80211_i.h"
  26 #include "driver-ops.h"
  27 #include "mesh.h"
  28
  29 #define IEEE80211_PROBE_DELAY (HZ / 33)
  30 #define IEEE80211_CHANNEL_TIME (HZ / 33)
  31 #define IEEE80211_PASSIVE_CHANNEL_TIME (HZ / 9)
  32
  33 void ieee80211_rx_bss_put(struct ieee80211_local *local,
  34                           struct ieee80211_bss *bss)
  35 {
  36         if (!bss)
  37                 return;
  38         cfg80211_put_bss(local->hw.wiphy,
  39                          container_of((void *)bss, struct cfg80211_bss, priv));
  40 }
  41
  42 static bool is_uapsd_supported(struct ieee802_11_elems *elems)
  43 {
  44         u8 qos_info;
  45
  46         if (elems->wmm_info && elems->wmm_info_len == 7
  47             && elems->wmm_info[5] == 1)
  48                 qos_info = elems->wmm_info[6];
  49         else if (elems->wmm_param && elems->wmm_param_len == 24
  50                  && elems->wmm_param[5] == 1)
  51                 qos_info = elems->wmm_param[6];
  52         else
  53                 /* no valid wmm information or parameter element found */
  54                 return false;
  55
  56         return qos_info & IEEE80211_WMM_IE_AP_QOSINFO_UAPSD;
  57 }
  58
  59 struct ieee80211_bss *
  60 ieee80211_bss_info_update(struct ieee80211_local *local,
  61                           struct ieee80211_rx_status *rx_status,
  62                           struct ieee80211_mgmt *mgmt, size_t len,
  63                           struct ieee802_11_elems *elems,
  64                           struct ieee80211_channel *channel)
  65 {
  66         bool beacon = ieee80211_is_beacon(mgmt->frame_control);
  67         struct cfg80211_bss *cbss;
  68         struct ieee80211_bss *bss;
  69         int clen, srlen;
  70         enum nl80211_bss_scan_width scan_width;
  71         s32 signal = 0;
  72
  73         if (local->hw.flags & IEEE80211_HW_SIGNAL_DBM)
  74                 signal = rx_status->signal * 100;
  75         else if (local->hw.flags & IEEE80211_HW_SIGNAL_UNSPEC)
  76                 signal = (rx_status->signal * 100) / local->hw.max_signal;
  77
  78         scan_width = NL80211_BSS_CHAN_WIDTH_20;
  79         if (rx_status->flag & RX_FLAG_5MHZ)
  80                 scan_width = NL80211_BSS_CHAN_WIDTH_5;
  81         if (rx_status->flag & RX_FLAG_10MHZ)
  82                 scan_width = NL80211_BSS_CHAN_WIDTH_10;
  83
  84         cbss = cfg80211_inform_bss_width_frame(local->hw.wiphy, channel,
  85                                                scan_width, mgmt, len, signal,
  86                                                GFP_ATOMIC);
  87         if (!cbss)
  88                 return NULL;
  89
  90         bss = (void *)cbss->priv;
  91
  92         if (beacon)
  93                 bss->device_ts_beacon = rx_status->device_timestamp;
  94         else
  95                 bss->device_ts_presp = rx_status->device_timestamp;
  96
  97         if (elems->parse_error) {
  98                 if (beacon)
  99                         bss->corrupt_data |= IEEE80211_BSS_CORRUPT_BEACON;
 100                 else
 101                         bss->corrupt_data |= IEEE80211_BSS_CORRUPT_PROBE_RESP;
 102         } else {
 103                 if (beacon)
 104                         bss->corrupt_data &= ~IEEE80211_BSS_CORRUPT_BEACON;
 105                 else
 106                         bss->corrupt_data &= ~IEEE80211_BSS_CORRUPT_PROBE_RESP;
 107         }
 108
 109         /* save the ERP value so that it is available at association time */
 110         if (elems->erp_info && (!elems->parse_error ||
 111                                 !(bss->valid_data & IEEE80211_BSS_VALID_ERP))) {
 112                 bss->erp_value = elems->erp_info[0];
 113                 bss->has_erp_value = true;
 114                 if (!elems->parse_error)
 115                         bss->valid_data |= IEEE80211_BSS_VALID_ERP;
 116         }
 117
 118         /* replace old supported rates if we get new values */
 119         if (!elems->parse_error ||
 120             !(bss->valid_data & IEEE80211_BSS_VALID_RATES)) {
 121                 srlen = 0;
 122                 if (elems->supp_rates) {
 123                         clen = IEEE80211_MAX_SUPP_RATES;
 124                         if (clen > elems->supp_rates_len)
 125                                 clen = elems->supp_rates_len;
 126                         memcpy(bss->supp_rates, elems->supp_rates, clen);
 127                         srlen += clen;
 128                 }
 129                 if (elems->ext_supp_rates) {
 130                         clen = IEEE80211_MAX_SUPP_RATES - srlen;
 131                         if (clen > elems->ext_supp_rates_len)
 132                                 clen = elems->ext_supp_rates_len;
 133                         memcpy(bss->supp_rates + srlen, elems->ext_supp_rates,
 134                                clen);
 135                         srlen += clen;
 136                 }
 137                 if (srlen) {
 138                         bss->supp_rates_len = srlen;
 139                         if (!elems->parse_error)
 140                                 bss->valid_data |= IEEE80211_BSS_VALID_RATES;
 141                 }
 142         }
 143
 144         if (!elems->parse_error ||
 145             !(bss->valid_data & IEEE80211_BSS_VALID_WMM)) {
 146                 bss->wmm_used = elems->wmm_param || elems->wmm_info;
 147                 bss->uapsd_supported = is_uapsd_supported(elems);
 148                 if (!elems->parse_error)
 149                         bss->valid_data |= IEEE80211_BSS_VALID_WMM;
 150         }
 151
 152         if (beacon) {
 153                 struct ieee80211_supported_band *sband =
 154                         local->hw.wiphy->bands[rx_status->band];
 155                 if (!(rx_status->flag & RX_FLAG_HT) &&
 156                     !(rx_status->flag & RX_FLAG_VHT))
 157                         bss->beacon_rate =
 158                                 &sband->bitrates[rx_status->rate_idx];
 159         }
 160
 161         return bss;
 162 }
 163
 164 void ieee80211_scan_rx(struct ieee80211_local *local, struct sk_buff *skb)
 165 {
 166         struct ieee80211_rx_status *rx_status = IEEE80211_SKB_RXCB(skb);
 167         struct ieee80211_sub_if_data *sdata1, *sdata2;
 168         struct ieee80211_mgmt *mgmt = (void *)skb->data;
 169         struct ieee80211_bss *bss;
 170         u8 *elements;
 171         struct ieee80211_channel *channel;
 172         size_t baselen;
 173         struct ieee802_11_elems elems;
 174
 175         if (skb->len < 24 ||
 176             (!ieee80211_is_probe_resp(mgmt->frame_control) &&
 177              !ieee80211_is_beacon(mgmt->frame_control)))
 178                 return;
 179
 180         sdata1 = rcu_dereference(local->scan_sdata);
 181         sdata2 = rcu_dereference(local->sched_scan_sdata);
 182
 183         if (likely(!sdata1 && !sdata2))
 184                 return;
 185
 186         if (ieee80211_is_probe_resp(mgmt->frame_control)) {
 187                 /* ignore ProbeResp to foreign address */
 188                 if ((!sdata1 || !ether_addr_equal(mgmt->da, sdata1->vif.addr)) &&
 189                     (!sdata2 || !ether_addr_equal(mgmt->da, sdata2->vif.addr)))
 190                         return;
 191
 192                 elements = mgmt->u.probe_resp.variable;
 193                 baselen = offsetof(struct ieee80211_mgmt, u.probe_resp.variable);
 194         } else {
 195                 baselen = offsetof(struct ieee80211_mgmt, u.beacon.variable);
 196                 elements = mgmt->u.beacon.variable;
 197         }
 198
 199         if (baselen > skb->len)
 200                 return;
 201
 202         ieee802_11_parse_elems(elements, skb->len - baselen, false, &elems);
 203
 204         channel = ieee80211_get_channel(local->hw.wiphy, rx_status->freq);
 205
 206         if (!channel || channel->flags & IEEE80211_CHAN_DISABLED)
 207                 return;
 208
 209         bss = ieee80211_bss_info_update(local, rx_status,
 210                                         mgmt, skb->len, &elems,
 211                                         channel);
 212         if (bss)
 213                 ieee80211_rx_bss_put(local, bss);
 214 }
 215
 216 static void
 217 ieee80211_prepare_scan_chandef(struct cfg80211_chan_def *chandef,
 218                                enum nl80211_bss_scan_width scan_width)
 219 {
 220         memset(chandef, 0, sizeof(*chandef));
 221         switch (scan_width) {
 222         case NL80211_BSS_CHAN_WIDTH_5:
 223                 chandef->width = NL80211_CHAN_WIDTH_5;
 224                 break;
 225         case NL80211_BSS_CHAN_WIDTH_10:
 226                 chandef->width = NL80211_CHAN_WIDTH_10;
 227                 break;
 228         default:
 229                 chandef->width = NL80211_CHAN_WIDTH_20_NOHT;
 230                 break;
 231         }
 232 }
 233
 234 /* return false if no more work */
 235 static bool ieee80211_prep_hw_scan(struct ieee80211_local *local)
 236 {
 237         struct cfg80211_scan_request *req = local->scan_req;
 238         struct cfg80211_chan_def chandef;
 239         u8 bands_used = 0;
 240         int i, ielen, n_chans;
 241
 242         if (test_bit(SCAN_HW_CANCELLED, &local->scanning))
 243                 return false;
 244
 245         if (local->hw.flags & IEEE80211_SINGLE_HW_SCAN_ON_ALL_BANDS) {
 246                 for (i = 0; i < req->n_channels; i++) {
 247                         local->hw_scan_req->req.channels[i] = req->channels[i];
 248                         bands_used |= BIT(req->channels[i]->band);
 249                 }
 250
 251                 n_chans = req->n_channels;
 252         } else {
 253                 do {
 254                         if (local->hw_scan_band == IEEE80211_NUM_BANDS)
 255                                 return false;
 256
 257                         n_chans = 0;
 258
 259                         for (i = 0; i < req->n_channels; i++) {
 260                                 if (req->channels[i]->band !=
 261                                     local->hw_scan_band)
 262                                         continue;
 263                                 local->hw_scan_req->req.channels[n_chans] =
 264                                                         req->channels[i];
 265                                 n_chans++;
 266                                 bands_used |= BIT(req->channels[i]->band);
 267                         }
 268
 269                         local->hw_scan_band++;
 270                 } while (!n_chans);
 271         }
 272
 273         local->hw_scan_req->req.n_channels = n_chans;
 274         ieee80211_prepare_scan_chandef(&chandef, req->scan_width);
 275
 276         ielen = ieee80211_build_preq_ies(local,
 277                                          (u8 *)local->hw_scan_req->req.ie,
 278                                          local->hw_scan_ies_bufsize,
 279                                          &local->hw_scan_req->ies,
 280                                          req->ie, req->ie_len,
 281                                          bands_used, req->rates, &chandef);
 282         local->hw_scan_req->req.ie_len = ielen;
 283         local->hw_scan_req->req.no_cck = req->no_cck;
 284
 285         return true;
 286 }
 287
 288 static void __ieee80211_scan_completed(struct ieee80211_hw *hw, bool aborted)
 289 {
 290         struct ieee80211_local *local = hw_to_local(hw);
 291         bool hw_scan = local->ops->hw_scan;
 292         bool was_scanning = local->scanning;
 293
 294         lockdep_assert_held(&local->mtx);
 295
 296         /*
 297          * It's ok to abort a not-yet-running scan (that
 298          * we have one at all will be verified by checking
 299          * local->scan_req next), but not to complete it
 300          * successfully.
 301          */
 302         if (WARN_ON(!local->scanning && !aborted))
 303                 aborted = true;
 304
 305         if (WARN_ON(!local->scan_req))
 306                 return;
 307
 308         if (hw_scan && !aborted &&
 309             !(local->hw.flags & IEEE80211_SINGLE_HW_SCAN_ON_ALL_BANDS) &&
 310             ieee80211_prep_hw_scan(local)) {
 311                 int rc;
 312
 313                 rc = drv_hw_scan(local,
 314                         rcu_dereference_protected(local->scan_sdata,
 315                                                   lockdep_is_held(&local->mtx)),
 316                         local->hw_scan_req);
 317
 318                 if (rc == 0)
 319                         return;
 320         }
 321
 322         kfree(local->hw_scan_req);
 323         local->hw_scan_req = NULL;
 324
 325         if (local->scan_req != local->int_scan_req)
 326                 cfg80211_scan_done(local->scan_req, aborted);
 327         local->scan_req = NULL;
 328         RCU_INIT_POINTER(local->scan_sdata, NULL);
 329
 330         local->scanning = 0;
 331         local->scan_chandef.chan = NULL;
 332
 333         /* Set power back to normal operating levels. */
 334         ieee80211_hw_config(local, 0);
 335
 336         if (!hw_scan) {
 337                 ieee80211_configure_filter(local);
 338                 drv_sw_scan_complete(local);
 339                 ieee80211_offchannel_return(local);
 340         }
 341
 342         ieee80211_recalc_idle(local);
 343
 344         ieee80211_mlme_notify_scan_completed(local);
 345         ieee80211_ibss_notify_scan_completed(local);
 346         ieee80211_mesh_notify_scan_completed(local);
 347         if (was_scanning)
 348                 ieee80211_start_next_roc(local);
 349 }
 350
 351 void ieee80211_scan_completed(struct ieee80211_hw *hw, bool aborted)
 352 {
 353         struct ieee80211_local *local = hw_to_local(hw);
 354
 355         trace_api_scan_completed(local, aborted);
 356
 357         set_bit(SCAN_COMPLETED, &local->scanning);
 358         if (aborted)
 359                 set_bit(SCAN_ABORTED, &local->scanning);
 360         ieee80211_queue_delayed_work(&local->hw, &local->scan_work, 0);
 361 }
 362 EXPORT_SYMBOL(ieee80211_scan_completed);
 363
 364 static int ieee80211_start_sw_scan(struct ieee80211_local *local)
 365 {
 366         /* Software scan is not supported in multi-channel cases */
 367         if (local->use_chanctx)
 368                 return -EOPNOTSUPP;
 369
 370         /*
 371          * Hardware/driver doesn't support hw_scan, so use software
 372          * scanning instead. First send a nullfunc frame with power save
 373          * bit on so that AP will buffer the frames for us while we are not
 374          * listening, then send probe requests to each channel and wait for
 375          * the responses. After all channels are scanned, tune back to the
 376          * original channel and send a nullfunc frame with power save bit
 377          * off to trigger the AP to send us all the buffered frames.
 378          *
 379          * Note that while local->sw_scanning is true everything else but
 380          * nullfunc frames and probe requests will be dropped in
 381          * ieee80211_tx_h_check_assoc().
 382          */
 383         drv_sw_scan_start(local);
 384
 385         local->leave_oper_channel_time = jiffies;
 386         local->next_scan_state = SCAN_DECISION;
 387         local->scan_channel_idx = 0;
 388
 389         ieee80211_offchannel_stop_vifs(local);
 390
 391         /* ensure nullfunc is transmitted before leaving operating channel */
 392         ieee80211_flush_queues(local, NULL);
 393
 394         ieee80211_configure_filter(local);
 395
 396         /* We need to set power level at maximum rate for scanning. */
 397         ieee80211_hw_config(local, 0);
 398
 399         ieee80211_queue_delayed_work(&local->hw,
 400                                      &local->scan_work, 0);
 401
 402         return 0;
 403 }
 404
 405 static bool ieee80211_can_scan(struct ieee80211_local *local,
 406                                struct ieee80211_sub_if_data *sdata)
 407 {
 408         if (local->radar_detect_enabled)
 409                 return false;
 410
 411         if (!list_empty(&local->roc_list))
 412                 return false;
 413
 414         if (sdata->vif.type == NL80211_IFTYPE_STATION &&
 415             sdata->u.mgd.flags & IEEE80211_STA_CONNECTION_POLL)
 416                 return false;
 417
 418         return true;
 419 }
 420
 421 void ieee80211_run_deferred_scan(struct ieee80211_local *local)
 422 {
 423         lockdep_assert_held(&local->mtx);
 424
 425         if (!local->scan_req || local->scanning)
 426                 return;
 427
 428         if (!ieee80211_can_scan(local,
 429                                 rcu_dereference_protected(
 430                                         local->scan_sdata,
 431                                         lockdep_is_held(&local->mtx))))
 432                 return;
 433
 434         ieee80211_queue_delayed_work(&local->hw, &local->scan_work,
 435                                      round_jiffies_relative(0));
 436 }
 437
 438 static void ieee80211_scan_state_send_probe(struct ieee80211_local *local,
 439                                             unsigned long *next_delay)
 440 {
 441         int i;
 442         struct ieee80211_sub_if_data *sdata;
 443         enum ieee80211_band band = local->hw.conf.chandef.chan->band;
 444         u32 tx_flags;
 445
 446         tx_flags = IEEE80211_TX_INTFL_OFFCHAN_TX_OK;
 447         if (local->scan_req->no_cck)
 448                 tx_flags |= IEEE80211_TX_CTL_NO_CCK_RATE;
 449
 450         sdata = rcu_dereference_protected(local->scan_sdata,
 451                                           lockdep_is_held(&local->mtx));
 452
 453         for (i = 0; i < local->scan_req->n_ssids; i++)
 454                 ieee80211_send_probe_req(
 455                         sdata, NULL,
 456                         local->scan_req->ssids[i].ssid,
 457                         local->scan_req->ssids[i].ssid_len,
 458                         local->scan_req->ie, local->scan_req->ie_len,
 459                         local->scan_req->rates[band], false,
 460                         tx_flags, local->hw.conf.chandef.chan, true);
 461
 462         /*
 463          * After sending probe requests, wait for probe responses
 464          * on the channel.
 465          */
 466         *next_delay = IEEE80211_CHANNEL_TIME;
 467         local->next_scan_state = SCAN_DECISION;
 468 }
 469
 470 static int __ieee80211_start_scan(struct ieee80211_sub_if_data *sdata,
 471                                   struct cfg80211_scan_request *req)
 472 {
 473         struct ieee80211_local *local = sdata->local;
 474         int rc;
 475
 476         lockdep_assert_held(&local->mtx);
 477
 478         if (local->scan_req)
 479                 return -EBUSY;
 480
 481         if (!ieee80211_can_scan(local, sdata)) {
 482                 /* wait for the work to finish/time out */
 483                 local->scan_req = req;
 484                 rcu_assign_pointer(local->scan_sdata, sdata);
 485                 return 0;
 486         }
 487
 488         if (local->ops->hw_scan) {
 489                 u8 *ies;
 490
 491                 local->hw_scan_ies_bufsize = local->scan_ies_len + req->ie_len;
 492
 493                 if (local->hw.flags & IEEE80211_SINGLE_HW_SCAN_ON_ALL_BANDS) {
 494                         int i, n_bands = 0;
 495                         u8 bands_counted = 0;
 496
 497                         for (i = 0; i < req->n_channels; i++) {
 498                                 if (bands_counted & BIT(req->channels[i]->band))
 499                                         continue;
 500                                 bands_counted |= BIT(req->channels[i]->band);
 501                                 n_bands++;
 502                         }
 503
 504                         local->hw_scan_ies_bufsize *= n_bands;
 505                 }
 506
 507                 local->hw_scan_req = kmalloc(
 508                                 sizeof(*local->hw_scan_req) +
 509                                 req->n_channels * sizeof(req->channels[0]) +
 510                                 local->hw_scan_ies_bufsize, GFP_KERNEL);
 511                 if (!local->hw_scan_req)
 512                         return -ENOMEM;
 513
 514                 local->hw_scan_req->req.ssids = req->ssids;
 515                 local->hw_scan_req->req.n_ssids = req->n_ssids;
 516                 ies = (u8 *)local->hw_scan_req +
 517                         sizeof(*local->hw_scan_req) +
 518                         req->n_channels * sizeof(req->channels[0]);
 519                 local->hw_scan_req->req.ie = ies;
 520                 local->hw_scan_req->req.flags = req->flags;
 521
 522                 local->hw_scan_band = 0;
 523
 524                 /*
 525                  * After allocating local->hw_scan_req, we must
 526                  * go through until ieee80211_prep_hw_scan(), so
 527                  * anything that might be changed here and leave
 528                  * this function early must not go after this
 529                  * allocation.
 530                  */
 531         }
 532
 533         local->scan_req = req;
 534         rcu_assign_pointer(local->scan_sdata, sdata);
 535
 536         if (local->ops->hw_scan) {
 537                 __set_bit(SCAN_HW_SCANNING, &local->scanning);
 538         } else if ((req->n_channels == 1) &&
 539                    (req->channels[0] == local->_oper_chandef.chan)) {
 540                 /*
 541                  * If we are scanning only on the operating channel
 542                  * then we do not need to stop normal activities
 543                  */
 544                 unsigned long next_delay;
 545
 546                 __set_bit(SCAN_ONCHANNEL_SCANNING, &local->scanning);
 547
 548                 ieee80211_recalc_idle(local);
 549
 550                 /* Notify driver scan is starting, keep order of operations
 551                  * same as normal software scan, in case that matters. */
 552                 drv_sw_scan_start(local);
 553
 554                 ieee80211_configure_filter(local); /* accept probe-responses */
 555
 556                 /* We need to ensure power level is at max for scanning. */
 557                 ieee80211_hw_config(local, 0);
 558
 559                 if ((req->channels[0]->flags &
 560                      IEEE80211_CHAN_NO_IR) ||
 561                     !local->scan_req->n_ssids) {
 562                         next_delay = IEEE80211_PASSIVE_CHANNEL_TIME;
 563                 } else {
 564                         ieee80211_scan_state_send_probe(local, &next_delay);
 565                         next_delay = IEEE80211_CHANNEL_TIME;
 566                 }
 567
 568                 /* Now, just wait a bit and we are all done! */
 569                 ieee80211_queue_delayed_work(&local->hw, &local->scan_work,
 570                                              next_delay);
 571                 return 0;
 572         } else {
 573                 /* Do normal software scan */
 574                 __set_bit(SCAN_SW_SCANNING, &local->scanning);
 575         }
 576
 577         ieee80211_recalc_idle(local);
 578
 579         if (local->ops->hw_scan) {
 580                 WARN_ON(!ieee80211_prep_hw_scan(local));
 581                 rc = drv_hw_scan(local, sdata, local->hw_scan_req);
 582         } else
 583                 rc = ieee80211_start_sw_scan(local);
 584
 585         if (rc) {
 586                 kfree(local->hw_scan_req);
 587                 local->hw_scan_req = NULL;
 588                 local->scanning = 0;
 589
 590                 ieee80211_recalc_idle(local);
 591
 592                 local->scan_req = NULL;
 593                 RCU_INIT_POINTER(local->scan_sdata, NULL);
 594         }
 595
 596         return rc;
 597 }
 598
 599 static unsigned long
 600 ieee80211_scan_get_channel_time(struct ieee80211_channel *chan)
 601 {
 602         /*
 603          * TODO: channel switching also consumes quite some time,
 604          * add that delay as well to get a better estimation
 605          */
 606         if (chan->flags & IEEE80211_CHAN_NO_IR)
 607                 return IEEE80211_PASSIVE_CHANNEL_TIME;
 608         return IEEE80211_PROBE_DELAY + IEEE80211_CHANNEL_TIME;
 609 }
 610
 611 static void ieee80211_scan_state_decision(struct ieee80211_local *local,
 612                                           unsigned long *next_delay)
 613 {
 614         bool associated = false;
 615         bool tx_empty = true;
 616         bool bad_latency;
 617         struct ieee80211_sub_if_data *sdata;
 618         struct ieee80211_channel *next_chan;
 619         enum mac80211_scan_state next_scan_state;
 620
 621         /*
 622          * check if at least one STA interface is associated,
 623          * check if at least one STA interface has pending tx frames
 624          * and grab the lowest used beacon interval
 625          */
 626         mutex_lock(&local->iflist_mtx);
 627         list_for_each_entry(sdata, &local->interfaces, list) {
 628                 if (!ieee80211_sdata_running(sdata))
 629                         continue;
 630
 631                 if (sdata->vif.type == NL80211_IFTYPE_STATION) {
 632                         if (sdata->u.mgd.associated) {
 633                                 associated = true;
 634
 635                                 if (!qdisc_all_tx_empty(sdata->dev)) {
 636                                         tx_empty = false;
 637                                         break;
 638                                 }
 639                         }
 640                 }
 641         }
 642         mutex_unlock(&local->iflist_mtx);
 643
 644         next_chan = local->scan_req->channels[local->scan_channel_idx];
 645
 646         /*
 647          * we're currently scanning a different channel, let's
 648          * see if we can scan another channel without interfering
 649          * with the current traffic situation.
 650          *
 651          * Keep good latency, do not stay off-channel more than 125 ms.
 652          */
 653
 654         bad_latency = time_after(jiffies +
 655                                  ieee80211_scan_get_channel_time(next_chan),
 656                                  local->leave_oper_channel_time + HZ / 8);
 657
 658         if (associated && !tx_empty) {
 659                 if (local->scan_req->flags & NL80211_SCAN_FLAG_LOW_PRIORITY)
 660                         next_scan_state = SCAN_ABORT;
 661                 else
 662                         next_scan_state = SCAN_SUSPEND;
 663         } else if (associated && bad_latency) {
 664                 next_scan_state = SCAN_SUSPEND;
 665         } else {
 666                 next_scan_state = SCAN_SET_CHANNEL;
 667         }
 668
 669         local->next_scan_state = next_scan_state;
 670
 671         *next_delay = 0;
 672 }
 673
 674 static void ieee80211_scan_state_set_channel(struct ieee80211_local *local,
 675                                              unsigned long *next_delay)
 676 {
 677         int skip;
 678         struct ieee80211_channel *chan;
 679         enum nl80211_bss_scan_width oper_scan_width;
 680
 681         skip = 0;
 682         chan = local->scan_req->channels[local->scan_channel_idx];
 683
 684         local->scan_chandef.chan = chan;
 685         local->scan_chandef.center_freq1 = chan->center_freq;
 686         local->scan_chandef.center_freq2 = 0;
 687         switch (local->scan_req->scan_width) {
 688         case NL80211_BSS_CHAN_WIDTH_5:
 689                 local->scan_chandef.width = NL80211_CHAN_WIDTH_5;
 690                 break;
 691         case NL80211_BSS_CHAN_WIDTH_10:
 692                 local->scan_chandef.width = NL80211_CHAN_WIDTH_10;
 693                 break;
 694         case NL80211_BSS_CHAN_WIDTH_20:
 695                 /* If scanning on oper channel, use whatever channel-type
 696                  * is currently in use.
 697                  */
 698                 oper_scan_width = cfg80211_chandef_to_scan_width(
 699                                         &local->_oper_chandef);
 700                 if (chan == local->_oper_chandef.chan &&
 701                     oper_scan_width == local->scan_req->scan_width)
 702                         local->scan_chandef = local->_oper_chandef;
 703                 else
 704                         local->scan_chandef.width = NL80211_CHAN_WIDTH_20_NOHT;
 705                 break;
 706         }
 707
 708         if (ieee80211_hw_config(local, IEEE80211_CONF_CHANGE_CHANNEL))
 709                 skip = 1;
 710
 711         /* advance state machine to next channel/band */
 712         local->scan_channel_idx++;
 713
 714         if (skip) {
 715                 /* if we skip this channel return to the decision state */
 716                 local->next_scan_state = SCAN_DECISION;
 717                 return;
 718         }
 719
 720         /*
 721          * Probe delay is used to update the NAV, cf. 11.1.3.2.2
 722          * (which unfortunately doesn't say _why_ step a) is done,
 723          * but it waits for the probe delay or until a frame is
 724          * received - and the received frame would update the NAV).
 725          * For now, we do not support waiting until a frame is
 726          * received.
 727          *
 728          * In any case, it is not necessary for a passive scan.
 729          */
 730         if (chan->flags & IEEE80211_CHAN_NO_IR ||
 731             !local->scan_req->n_ssids) {
 732                 *next_delay = IEEE80211_PASSIVE_CHANNEL_TIME;
 733                 local->next_scan_state = SCAN_DECISION;
 734                 return;
 735         }
 736
 737         /* active scan, send probes */
 738         *next_delay = IEEE80211_PROBE_DELAY;
 739         local->next_scan_state = SCAN_SEND_PROBE;
 740 }
 741
 742 static void ieee80211_scan_state_suspend(struct ieee80211_local *local,
 743                                          unsigned long *next_delay)
 744 {
 745         /* switch back to the operating channel */
 746         local->scan_chandef.chan = NULL;
 747         ieee80211_hw_config(local, IEEE80211_CONF_CHANGE_CHANNEL);
 748
 749         /* disable PS */
 750         ieee80211_offchannel_return(local);
 751
 752         *next_delay = HZ / 5;
 753         /* afterwards, resume scan & go to next channel */
 754         local->next_scan_state = SCAN_RESUME;
 755 }
 756
 757 static void ieee80211_scan_state_resume(struct ieee80211_local *local,
 758                                         unsigned long *next_delay)
 759 {
 760         ieee80211_offchannel_stop_vifs(local);
 761
 762         if (local->ops->flush) {
 763                 ieee80211_flush_queues(local, NULL);
 764                 *next_delay = 0;
 765         } else
 766                 *next_delay = HZ / 10;
 767
 768         /* remember when we left the operating channel */
 769         local->leave_oper_channel_time = jiffies;
 770
 771         /* advance to the next channel to be scanned */
 772         local->next_scan_state = SCAN_SET_CHANNEL;
 773 }
 774
 775 void ieee80211_scan_work(struct work_struct *work)
 776 {
 777         struct ieee80211_local *local =
 778                 container_of(work, struct ieee80211_local, scan_work.work);
 779         struct ieee80211_sub_if_data *sdata;
 780         unsigned long next_delay = 0;
 781         bool aborted;
 782
 783         mutex_lock(&local->mtx);
 784
 785         sdata = rcu_dereference_protected(local->scan_sdata,
 786                                           lockdep_is_held(&local->mtx));
 787
 788         /* When scanning on-channel, the first-callback means completed. */
 789         if (test_bit(SCAN_ONCHANNEL_SCANNING, &local->scanning)) {
 790                 aborted = test_and_clear_bit(SCAN_ABORTED, &local->scanning);
 791                 goto out_complete;
 792         }
 793
 794         if (test_and_clear_bit(SCAN_COMPLETED, &local->scanning)) {
 795                 aborted = test_and_clear_bit(SCAN_ABORTED, &local->scanning);
 796                 goto out_complete;
 797         }
 798
 799         if (!sdata || !local->scan_req)
 800                 goto out;
 801
 802         if (local->scan_req && !local->scanning) {
 803                 struct cfg80211_scan_request *req = local->scan_req;
 804                 int rc;
 805
 806                 local->scan_req = NULL;
 807                 RCU_INIT_POINTER(local->scan_sdata, NULL);
 808
 809                 rc = __ieee80211_start_scan(sdata, req);
 810                 if (rc) {
 811                         /* need to complete scan in cfg80211 */
 812                         local->scan_req = req;
 813                         aborted = true;
 814                         goto out_complete;
 815                 } else
 816                         goto out;
 817         }
 818
 819         /*
 820          * as long as no delay is required advance immediately
 821          * without scheduling a new work
 822          */
 823         do {
 824                 if (!ieee80211_sdata_running(sdata)) {
 825                         aborted = true;
 826                         goto out_complete;
 827                 }
 828
 829                 switch (local->next_scan_state) {
 830                 case SCAN_DECISION:
 831                         /* if no more bands/channels left, complete scan */
 832                         if (local->scan_channel_idx >= local->scan_req->n_channels) {
 833                                 aborted = false;
 834                                 goto out_complete;
 835                         }
 836                         ieee80211_scan_state_decision(local, &next_delay);
 837                         break;
 838                 case SCAN_SET_CHANNEL:
 839                         ieee80211_scan_state_set_channel(local, &next_delay);
 840                         break;
 841                 case SCAN_SEND_PROBE:
 842                         ieee80211_scan_state_send_probe(local, &next_delay);
 843                         break;
 844                 case SCAN_SUSPEND:
 845                         ieee80211_scan_state_suspend(local, &next_delay);
 846                         break;
 847                 case SCAN_RESUME:
 848                         ieee80211_scan_state_resume(local, &next_delay);
 849                         break;
 850                 case SCAN_ABORT:
 851                         aborted = true;
 852                         goto out_complete;
 853                 }
 854         } while (next_delay == 0);
 855
 856         ieee80211_queue_delayed_work(&local->hw, &local->scan_work, next_delay);
 857         goto out;
 858
 859 out_complete:
 860         __ieee80211_scan_completed(&local->hw, aborted);
 861 out:
 862         mutex_unlock(&local->mtx);
 863 }
 864
 865 int ieee80211_request_scan(struct ieee80211_sub_if_data *sdata,
 866                            struct cfg80211_scan_request *req)
 867 {
 868         int res;
 869
 870         mutex_lock(&sdata->local->mtx);
 871         res = __ieee80211_start_scan(sdata, req);
 872         mutex_unlock(&sdata->local->mtx);
 873
 874         return res;
 875 }
 876
 877 int ieee80211_request_ibss_scan(struct ieee80211_sub_if_data *sdata,
 878                                 const u8 *ssid, u8 ssid_len,
 879                                 struct ieee80211_channel *chan,
 880                                 enum nl80211_bss_scan_width scan_width)
 881 {
 882         struct ieee80211_local *local = sdata->local;
 883         int ret = -EBUSY;
 884         enum ieee80211_band band;
 885
 886         mutex_lock(&local->mtx);
 887
 888         /* busy scanning */
 889         if (local->scan_req)
 890                 goto unlock;
 891
 892         /* fill internal scan request */
 893         if (!chan) {
 894                 int i, max_n;
 895                 int n_ch = 0;
 896
 897                 for (band = 0; band < IEEE80211_NUM_BANDS; band++) {
 898                         if (!local->hw.wiphy->bands[band])
 899                                 continue;
 900
 901                         max_n = local->hw.wiphy->bands[band]->n_channels;
 902                         for (i = 0; i < max_n; i++) {
 903                                 struct ieee80211_channel *tmp_ch =
 904                                     &local->hw.wiphy->bands[band]->channels[i];
 905
 906                                 if (tmp_ch->flags & (IEEE80211_CHAN_NO_IR |
 907                                                      IEEE80211_CHAN_DISABLED))
 908                                         continue;
 909
 910                                 local->int_scan_req->channels[n_ch] = tmp_ch;
 911                                 n_ch++;
 912                         }
 913                 }
 914
 915                 if (WARN_ON_ONCE(n_ch == 0))
 916                         goto unlock;
 917
 918                 local->int_scan_req->n_channels = n_ch;
 919         } else {
 920                 if (WARN_ON_ONCE(chan->flags & (IEEE80211_CHAN_NO_IR |
 921                                                 IEEE80211_CHAN_DISABLED)))
 922                         goto unlock;
 923
 924                 local->int_scan_req->channels[0] = chan;
 925                 local->int_scan_req->n_channels = 1;
 926         }
 927
 928         local->int_scan_req->ssids = &local->scan_ssid;
 929         local->int_scan_req->n_ssids = 1;
 930         local->int_scan_req->scan_width = scan_width;
 931         memcpy(local->int_scan_req->ssids[0].ssid, ssid, IEEE80211_MAX_SSID_LEN);
 932         local->int_scan_req->ssids[0].ssid_len = ssid_len;
 933
 934         ret = __ieee80211_start_scan(sdata, sdata->local->int_scan_req);
 935  unlock:
 936         mutex_unlock(&local->mtx);
 937         return ret;
 938 }
 939
 940 /*
 941  * Only call this function when a scan can't be queued -- under RTNL.
 942  */
 943 void ieee80211_scan_cancel(struct ieee80211_local *local)
 944 {
 945         /*
 946          * We are canceling software scan, or deferred scan that was not
 947          * yet really started (see __ieee80211_start_scan ).
 948          *
 949          * Regarding hardware scan:
 950          * - we can not call  __ieee80211_scan_completed() as when
 951          *   SCAN_HW_SCANNING bit is set this function change
 952          *   local->hw_scan_req to operate on 5G band, what race with
 953          *   driver which can use local->hw_scan_req
 954          *
 955          * - we can not cancel scan_work since driver can schedule it
 956          *   by ieee80211_scan_completed(..., true) to finish scan
 957          *
 958          * Hence we only call the cancel_hw_scan() callback, but the low-level
 959          * driver is still responsible for calling ieee80211_scan_completed()
 960          * after the scan was completed/aborted.
 961          */
 962
 963         mutex_lock(&local->mtx);
 964         if (!local->scan_req)
 965                 goto out;
 966
 967         /*
 968          * We have a scan running and the driver already reported completion,
 969          * but the worker hasn't run yet or is stuck on the mutex - mark it as
 970          * cancelled.
 971          */
 972         if (test_bit(SCAN_HW_SCANNING, &local->scanning) &&
 973             test_bit(SCAN_COMPLETED, &local->scanning)) {
 974                 set_bit(SCAN_HW_CANCELLED, &local->scanning);
 975                 goto out;
 976         }
 977
 978         if (test_bit(SCAN_HW_SCANNING, &local->scanning)) {
 979                 /*
 980                  * Make sure that __ieee80211_scan_completed doesn't trigger a
 981                  * scan on another band.
 982                  */
 983                 set_bit(SCAN_HW_CANCELLED, &local->scanning);
 984                 if (local->ops->cancel_hw_scan)
 985                         drv_cancel_hw_scan(local,
 986                                 rcu_dereference_protected(local->scan_sdata,
 987                                                 lockdep_is_held(&local->mtx)));
 988                 goto out;
 989         }
 990
 991         /*
 992          * If the work is currently running, it must be blocked on
 993          * the mutex, but we'll set scan_sdata = NULL and it'll
 994          * simply exit once it acquires the mutex.
 995          */
 996         cancel_delayed_work(&local->scan_work);
 997         /* and clean up */
 998         __ieee80211_scan_completed(&local->hw, true);
 999 out:
1000         mutex_unlock(&local->mtx);
1001 }
1002
1003 int __ieee80211_request_sched_scan_start(struct ieee80211_sub_if_data *sdata,
1004                                         struct cfg80211_sched_scan_request *req)
1005 {
1006         struct ieee80211_local *local = sdata->local;
1007         struct ieee80211_scan_ies sched_scan_ies = {};
1008         struct cfg80211_chan_def chandef;
1009         int ret, i, iebufsz, num_bands = 0;
1010         u32 rate_masks[IEEE80211_NUM_BANDS] = {};
1011         u8 bands_used = 0;
1012         u8 *ie;
1013         size_t len;
1014
1015         iebufsz = local->scan_ies_len + req->ie_len;
1016
1017         lockdep_assert_held(&local->mtx);
1018
1019         if (!local->ops->sched_scan_start)
1020                 return -ENOTSUPP;
1021
1022         for (i = 0; i < IEEE80211_NUM_BANDS; i++) {
1023                 if (local->hw.wiphy->bands[i]) {
1024                         bands_used |= BIT(i);
1025                         rate_masks[i] = (u32) -1;
1026                         num_bands++;
1027                 }
1028         }
1029
1030         ie = kzalloc(num_bands * iebufsz, GFP_KERNEL);
1031         if (!ie) {
1032                 ret = -ENOMEM;
1033                 goto out;
1034         }
1035
1036         ieee80211_prepare_scan_chandef(&chandef, req->scan_width);
1037
1038         len = ieee80211_build_preq_ies(local, ie, num_bands * iebufsz,
1039                                        &sched_scan_ies, req->ie,
1040                                        req->ie_len, bands_used,
1041                                        rate_masks, &chandef);
1042
1043         ret = drv_sched_scan_start(local, sdata, req, &sched_scan_ies);
1044         if (ret == 0) {
1045                 rcu_assign_pointer(local->sched_scan_sdata, sdata);
1046                 local->sched_scan_req = req;
1047         }
1048
1049         kfree(ie);
1050
1051 out:
1052         if (ret) {
1053                 /* Clean in case of failure after HW restart or upon resume. */
1054                 RCU_INIT_POINTER(local->sched_scan_sdata, NULL);
1055                 local->sched_scan_req = NULL;
1056         }
1057
1058         return ret;
1059 }
1060
1061 int ieee80211_request_sched_scan_start(struct ieee80211_sub_if_data *sdata,
1062                                        struct cfg80211_sched_scan_request *req)
1063 {
1064         struct ieee80211_local *local = sdata->local;
1065         int ret;
1066
1067         mutex_lock(&local->mtx);
1068
1069         if (rcu_access_pointer(local->sched_scan_sdata)) {
1070                 mutex_unlock(&local->mtx);
1071                 return -EBUSY;
1072         }
1073
1074         ret = __ieee80211_request_sched_scan_start(sdata, req);
1075
1076         mutex_unlock(&local->mtx);
1077         return ret;
1078 }
1079
1080 int ieee80211_request_sched_scan_stop(struct ieee80211_sub_if_data *sdata)
1081 {
1082         struct ieee80211_local *local = sdata->local;
1083         int ret = 0;
1084
1085         mutex_lock(&local->mtx);
1086
1087         if (!local->ops->sched_scan_stop) {
1088                 ret = -ENOTSUPP;
1089                 goto out;
1090         }
1091
1092         /* We don't want to restart sched scan anymore. */
1093         local->sched_scan_req = NULL;
1094
1095         if (rcu_access_pointer(local->sched_scan_sdata)) {
1096                 ret = drv_sched_scan_stop(local, sdata);
1097                 if (!ret)
1098                         RCU_INIT_POINTER(local->sched_scan_sdata, NULL);
1099         }
1100 out:
1101         mutex_unlock(&local->mtx);
1102
1103         return ret;
1104 }
1105
1106 void ieee80211_sched_scan_results(struct ieee80211_hw *hw)
1107 {
1108         struct ieee80211_local *local = hw_to_local(hw);
1109
1110         trace_api_sched_scan_results(local);
1111
1112         cfg80211_sched_scan_results(hw->wiphy);
1113 }
1114 EXPORT_SYMBOL(ieee80211_sched_scan_results);
1115
1116 void ieee80211_sched_scan_end(struct ieee80211_local *local)
1117 {
1118         mutex_lock(&local->mtx);
1119
1120         if (!rcu_access_pointer(local->sched_scan_sdata)) {
1121                 mutex_unlock(&local->mtx);
1122                 return;
1123         }
1124
1125         RCU_INIT_POINTER(local->sched_scan_sdata, NULL);
1126
1127         /* If sched scan was aborted by the driver. */
1128         local->sched_scan_req = NULL;
1129
1130         mutex_unlock(&local->mtx);
1131
1132         cfg80211_sched_scan_stopped(local->hw.wiphy);
1133 }
1134
1135 void ieee80211_sched_scan_stopped_work(struct work_struct *work)
1136 {
1137         struct ieee80211_local *local =
1138                 container_of(work, struct ieee80211_local,
1139                              sched_scan_stopped_work);
1140
1141         ieee80211_sched_scan_end(local);
1142 }
1143
1144 void ieee80211_sched_scan_stopped(struct ieee80211_hw *hw)
1145 {
1146         struct ieee80211_local *local = hw_to_local(hw);
1147
1148         trace_api_sched_scan_stopped(local);
1149
1150         schedule_work(&local->sched_scan_stopped_work);
1151 }
1152 EXPORT_SYMBOL(ieee80211_sched_scan_stopped);