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                 struct cfg80211_scan_request *scan_req;
 188                 struct cfg80211_sched_scan_request *sched_scan_req;
 189
 190                 scan_req = rcu_dereference(local->scan_req);
 191                 sched_scan_req = rcu_dereference(local->sched_scan_req);
 192
 193                 /* ignore ProbeResp to foreign address unless scanning
 194                  * with randomised address
 195                  */
 196                 if (!(sdata1 &&
 197                       (ether_addr_equal(mgmt->da, sdata1->vif.addr) ||
 198                        scan_req->flags & NL80211_SCAN_FLAG_RANDOM_ADDR)) &&
 199                     !(sdata2 &&
 200                       (ether_addr_equal(mgmt->da, sdata2->vif.addr) ||
 201                        sched_scan_req->flags & NL80211_SCAN_FLAG_RANDOM_ADDR)))
 202                         return;
 203
 204                 elements = mgmt->u.probe_resp.variable;
 205                 baselen = offsetof(struct ieee80211_mgmt, u.probe_resp.variable);
 206         } else {
 207                 baselen = offsetof(struct ieee80211_mgmt, u.beacon.variable);
 208                 elements = mgmt->u.beacon.variable;
 209         }
 210
 211         if (baselen > skb->len)
 212                 return;
 213
 214         ieee802_11_parse_elems(elements, skb->len - baselen, false, &elems);
 215
 216         channel = ieee80211_get_channel(local->hw.wiphy, rx_status->freq);
 217
 218         if (!channel || channel->flags & IEEE80211_CHAN_DISABLED)
 219                 return;
 220
 221         bss = ieee80211_bss_info_update(local, rx_status,
 222                                         mgmt, skb->len, &elems,
 223                                         channel);
 224         if (bss)
 225                 ieee80211_rx_bss_put(local, bss);
 226 }
 227
 228 static void
 229 ieee80211_prepare_scan_chandef(struct cfg80211_chan_def *chandef,
 230                                enum nl80211_bss_scan_width scan_width)
 231 {
 232         memset(chandef, 0, sizeof(*chandef));
 233         switch (scan_width) {
 234         case NL80211_BSS_CHAN_WIDTH_5:
 235                 chandef->width = NL80211_CHAN_WIDTH_5;
 236                 break;
 237         case NL80211_BSS_CHAN_WIDTH_10:
 238                 chandef->width = NL80211_CHAN_WIDTH_10;
 239                 break;
 240         default:
 241                 chandef->width = NL80211_CHAN_WIDTH_20_NOHT;
 242                 break;
 243         }
 244 }
 245
 246 /* return false if no more work */
 247 static bool ieee80211_prep_hw_scan(struct ieee80211_local *local)
 248 {
 249         struct cfg80211_scan_request *req;
 250         struct cfg80211_chan_def chandef;
 251         u8 bands_used = 0;
 252         int i, ielen, n_chans;
 253
 254         req = rcu_dereference_protected(local->scan_req,
 255                                         lockdep_is_held(&local->mtx));
 256
 257         if (test_bit(SCAN_HW_CANCELLED, &local->scanning))
 258                 return false;
 259
 260         if (local->hw.flags & IEEE80211_SINGLE_HW_SCAN_ON_ALL_BANDS) {
 261                 for (i = 0; i < req->n_channels; i++) {
 262                         local->hw_scan_req->req.channels[i] = req->channels[i];
 263                         bands_used |= BIT(req->channels[i]->band);
 264                 }
 265
 266                 n_chans = req->n_channels;
 267         } else {
 268                 do {
 269                         if (local->hw_scan_band == IEEE80211_NUM_BANDS)
 270                                 return false;
 271
 272                         n_chans = 0;
 273
 274                         for (i = 0; i < req->n_channels; i++) {
 275                                 if (req->channels[i]->band !=
 276                                     local->hw_scan_band)
 277                                         continue;
 278                                 local->hw_scan_req->req.channels[n_chans] =
 279                                                         req->channels[i];
 280                                 n_chans++;
 281                                 bands_used |= BIT(req->channels[i]->band);
 282                         }
 283
 284                         local->hw_scan_band++;
 285                 } while (!n_chans);
 286         }
 287
 288         local->hw_scan_req->req.n_channels = n_chans;
 289         ieee80211_prepare_scan_chandef(&chandef, req->scan_width);
 290
 291         ielen = ieee80211_build_preq_ies(local,
 292                                          (u8 *)local->hw_scan_req->req.ie,
 293                                          local->hw_scan_ies_bufsize,
 294                                          &local->hw_scan_req->ies,
 295                                          req->ie, req->ie_len,
 296                                          bands_used, req->rates, &chandef);
 297         local->hw_scan_req->req.ie_len = ielen;
 298         local->hw_scan_req->req.no_cck = req->no_cck;
 299         ether_addr_copy(local->hw_scan_req->req.mac_addr, req->mac_addr);
 300         ether_addr_copy(local->hw_scan_req->req.mac_addr_mask,
 301                         req->mac_addr_mask);
 302
 303         return true;
 304 }
 305
 306 static void __ieee80211_scan_completed(struct ieee80211_hw *hw, bool aborted)
 307 {
 308         struct ieee80211_local *local = hw_to_local(hw);
 309         bool hw_scan = local->ops->hw_scan;
 310         bool was_scanning = local->scanning;
 311         struct cfg80211_scan_request *scan_req;
 312         struct ieee80211_sub_if_data *scan_sdata;
 313
 314         lockdep_assert_held(&local->mtx);
 315
 316         /*
 317          * It's ok to abort a not-yet-running scan (that
 318          * we have one at all will be verified by checking
 319          * local->scan_req next), but not to complete it
 320          * successfully.
 321          */
 322         if (WARN_ON(!local->scanning && !aborted))
 323                 aborted = true;
 324
 325         if (WARN_ON(!local->scan_req))
 326                 return;
 327
 328         if (hw_scan && !aborted &&
 329             !(local->hw.flags & IEEE80211_SINGLE_HW_SCAN_ON_ALL_BANDS) &&
 330             ieee80211_prep_hw_scan(local)) {
 331                 int rc;
 332
 333                 rc = drv_hw_scan(local,
 334                         rcu_dereference_protected(local->scan_sdata,
 335                                                   lockdep_is_held(&local->mtx)),
 336                         local->hw_scan_req);
 337
 338                 if (rc == 0)
 339                         return;
 340         }
 341
 342         kfree(local->hw_scan_req);
 343         local->hw_scan_req = NULL;
 344
 345         scan_req = rcu_dereference_protected(local->scan_req,
 346                                              lockdep_is_held(&local->mtx));
 347
 348         if (scan_req != local->int_scan_req)
 349                 cfg80211_scan_done(scan_req, aborted);
 350         RCU_INIT_POINTER(local->scan_req, NULL);
 351
 352         scan_sdata = rcu_dereference_protected(local->scan_sdata,
 353                                                lockdep_is_held(&local->mtx));
 354         RCU_INIT_POINTER(local->scan_sdata, NULL);
 355
 356         local->scanning = 0;
 357         local->scan_chandef.chan = NULL;
 358
 359         /* Set power back to normal operating levels. */
 360         ieee80211_hw_config(local, 0);
 361
 362         if (!hw_scan) {
 363                 ieee80211_configure_filter(local);
 364                 drv_sw_scan_complete(local, scan_sdata);
 365                 ieee80211_offchannel_return(local);
 366         }
 367
 368         ieee80211_recalc_idle(local);
 369
 370         ieee80211_mlme_notify_scan_completed(local);
 371         ieee80211_ibss_notify_scan_completed(local);
 372         ieee80211_mesh_notify_scan_completed(local);
 373         if (was_scanning)
 374                 ieee80211_start_next_roc(local);
 375 }
 376
 377 void ieee80211_scan_completed(struct ieee80211_hw *hw, bool aborted)
 378 {
 379         struct ieee80211_local *local = hw_to_local(hw);
 380
 381         trace_api_scan_completed(local, aborted);
 382
 383         set_bit(SCAN_COMPLETED, &local->scanning);
 384         if (aborted)
 385                 set_bit(SCAN_ABORTED, &local->scanning);
 386         ieee80211_queue_delayed_work(&local->hw, &local->scan_work, 0);
 387 }
 388 EXPORT_SYMBOL(ieee80211_scan_completed);
 389
 390 static int ieee80211_start_sw_scan(struct ieee80211_local *local,
 391                                    struct ieee80211_sub_if_data *sdata)
 392 {
 393         /* Software scan is not supported in multi-channel cases */
 394         if (local->use_chanctx)
 395                 return -EOPNOTSUPP;
 396
 397         /*
 398          * Hardware/driver doesn't support hw_scan, so use software
 399          * scanning instead. First send a nullfunc frame with power save
 400          * bit on so that AP will buffer the frames for us while we are not
 401          * listening, then send probe requests to each channel and wait for
 402          * the responses. After all channels are scanned, tune back to the
 403          * original channel and send a nullfunc frame with power save bit
 404          * off to trigger the AP to send us all the buffered frames.
 405          *
 406          * Note that while local->sw_scanning is true everything else but
 407          * nullfunc frames and probe requests will be dropped in
 408          * ieee80211_tx_h_check_assoc().
 409          */
 410         drv_sw_scan_start(local, sdata, local->scan_addr);
 411
 412         local->leave_oper_channel_time = jiffies;
 413         local->next_scan_state = SCAN_DECISION;
 414         local->scan_channel_idx = 0;
 415
 416         ieee80211_offchannel_stop_vifs(local);
 417
 418         /* ensure nullfunc is transmitted before leaving operating channel */
 419         ieee80211_flush_queues(local, NULL, false);
 420
 421         ieee80211_configure_filter(local);
 422
 423         /* We need to set power level at maximum rate for scanning. */
 424         ieee80211_hw_config(local, 0);
 425
 426         ieee80211_queue_delayed_work(&local->hw,
 427                                      &local->scan_work, 0);
 428
 429         return 0;
 430 }
 431
 432 static bool ieee80211_can_scan(struct ieee80211_local *local,
 433                                struct ieee80211_sub_if_data *sdata)
 434 {
 435         if (ieee80211_is_radar_required(local))
 436                 return false;
 437
 438         if (!list_empty(&local->roc_list))
 439                 return false;
 440
 441         if (sdata->vif.type == NL80211_IFTYPE_STATION &&
 442             sdata->u.mgd.flags & IEEE80211_STA_CONNECTION_POLL)
 443                 return false;
 444
 445         return true;
 446 }
 447
 448 void ieee80211_run_deferred_scan(struct ieee80211_local *local)
 449 {
 450         lockdep_assert_held(&local->mtx);
 451
 452         if (!local->scan_req || local->scanning)
 453                 return;
 454
 455         if (!ieee80211_can_scan(local,
 456                                 rcu_dereference_protected(
 457                                         local->scan_sdata,
 458                                         lockdep_is_held(&local->mtx))))
 459                 return;
 460
 461         ieee80211_queue_delayed_work(&local->hw, &local->scan_work,
 462                                      round_jiffies_relative(0));
 463 }
 464
 465 static void ieee80211_scan_state_send_probe(struct ieee80211_local *local,
 466                                             unsigned long *next_delay)
 467 {
 468         int i;
 469         struct ieee80211_sub_if_data *sdata;
 470         struct cfg80211_scan_request *scan_req;
 471         enum ieee80211_band band = local->hw.conf.chandef.chan->band;
 472         u32 tx_flags;
 473
 474         scan_req = rcu_dereference_protected(local->scan_req,
 475                                              lockdep_is_held(&local->mtx));
 476
 477         tx_flags = IEEE80211_TX_INTFL_OFFCHAN_TX_OK;
 478         if (scan_req->no_cck)
 479                 tx_flags |= IEEE80211_TX_CTL_NO_CCK_RATE;
 480
 481         sdata = rcu_dereference_protected(local->scan_sdata,
 482                                           lockdep_is_held(&local->mtx));
 483
 484         for (i = 0; i < scan_req->n_ssids; i++)
 485                 ieee80211_send_probe_req(
 486                         sdata, local->scan_addr, NULL,
 487                         scan_req->ssids[i].ssid, scan_req->ssids[i].ssid_len,
 488                         scan_req->ie, scan_req->ie_len,
 489                         scan_req->rates[band], false,
 490                         tx_flags, local->hw.conf.chandef.chan, true);
 491
 492         /*
 493          * After sending probe requests, wait for probe responses
 494          * on the channel.
 495          */
 496         *next_delay = IEEE80211_CHANNEL_TIME;
 497         local->next_scan_state = SCAN_DECISION;
 498 }
 499
 500 static int __ieee80211_start_scan(struct ieee80211_sub_if_data *sdata,
 501                                   struct cfg80211_scan_request *req)
 502 {
 503         struct ieee80211_local *local = sdata->local;
 504         int rc;
 505
 506         lockdep_assert_held(&local->mtx);
 507
 508         if (local->scan_req || ieee80211_is_radar_required(local))
 509                 return -EBUSY;
 510
 511         if (!ieee80211_can_scan(local, sdata)) {
 512                 /* wait for the work to finish/time out */
 513                 rcu_assign_pointer(local->scan_req, req);
 514                 rcu_assign_pointer(local->scan_sdata, sdata);
 515                 return 0;
 516         }
 517
 518         if (local->ops->hw_scan) {
 519                 u8 *ies;
 520
 521                 local->hw_scan_ies_bufsize = local->scan_ies_len + req->ie_len;
 522
 523                 if (local->hw.flags & IEEE80211_SINGLE_HW_SCAN_ON_ALL_BANDS) {
 524                         int i, n_bands = 0;
 525                         u8 bands_counted = 0;
 526
 527                         for (i = 0; i < req->n_channels; i++) {
 528                                 if (bands_counted & BIT(req->channels[i]->band))
 529                                         continue;
 530                                 bands_counted |= BIT(req->channels[i]->band);
 531                                 n_bands++;
 532                         }
 533
 534                         local->hw_scan_ies_bufsize *= n_bands;
 535                 }
 536
 537                 local->hw_scan_req = kmalloc(
 538                                 sizeof(*local->hw_scan_req) +
 539                                 req->n_channels * sizeof(req->channels[0]) +
 540                                 local->hw_scan_ies_bufsize, GFP_KERNEL);
 541                 if (!local->hw_scan_req)
 542                         return -ENOMEM;
 543
 544                 local->hw_scan_req->req.ssids = req->ssids;
 545                 local->hw_scan_req->req.n_ssids = req->n_ssids;
 546                 ies = (u8 *)local->hw_scan_req +
 547                         sizeof(*local->hw_scan_req) +
 548                         req->n_channels * sizeof(req->channels[0]);
 549                 local->hw_scan_req->req.ie = ies;
 550                 local->hw_scan_req->req.flags = req->flags;
 551
 552                 local->hw_scan_band = 0;
 553
 554                 /*
 555                  * After allocating local->hw_scan_req, we must
 556                  * go through until ieee80211_prep_hw_scan(), so
 557                  * anything that might be changed here and leave
 558                  * this function early must not go after this
 559                  * allocation.
 560                  */
 561         }
 562
 563         rcu_assign_pointer(local->scan_req, req);
 564         rcu_assign_pointer(local->scan_sdata, sdata);
 565
 566         if (req->flags & NL80211_SCAN_FLAG_RANDOM_ADDR)
 567                 get_random_mask_addr(local->scan_addr,
 568                                      req->mac_addr,
 569                                      req->mac_addr_mask);
 570         else
 571                 memcpy(local->scan_addr, sdata->vif.addr, ETH_ALEN);
 572
 573         if (local->ops->hw_scan) {
 574                 __set_bit(SCAN_HW_SCANNING, &local->scanning);
 575         } else if ((req->n_channels == 1) &&
 576                    (req->channels[0] == local->_oper_chandef.chan)) {
 577                 /*
 578                  * If we are scanning only on the operating channel
 579                  * then we do not need to stop normal activities
 580                  */
 581                 unsigned long next_delay;
 582
 583                 __set_bit(SCAN_ONCHANNEL_SCANNING, &local->scanning);
 584
 585                 ieee80211_recalc_idle(local);
 586
 587                 /* Notify driver scan is starting, keep order of operations
 588                  * same as normal software scan, in case that matters. */
 589                 drv_sw_scan_start(local, sdata, local->scan_addr);
 590
 591                 ieee80211_configure_filter(local); /* accept probe-responses */
 592
 593                 /* We need to ensure power level is at max for scanning. */
 594                 ieee80211_hw_config(local, 0);
 595
 596                 if ((req->channels[0]->flags &
 597                      IEEE80211_CHAN_NO_IR) ||
 598                     !req->n_ssids) {
 599                         next_delay = IEEE80211_PASSIVE_CHANNEL_TIME;
 600                 } else {
 601                         ieee80211_scan_state_send_probe(local, &next_delay);
 602                         next_delay = IEEE80211_CHANNEL_TIME;
 603                 }
 604
 605                 /* Now, just wait a bit and we are all done! */
 606                 ieee80211_queue_delayed_work(&local->hw, &local->scan_work,
 607                                              next_delay);
 608                 return 0;
 609         } else {
 610                 /* Do normal software scan */
 611                 __set_bit(SCAN_SW_SCANNING, &local->scanning);
 612         }
 613
 614         ieee80211_recalc_idle(local);
 615
 616         if (local->ops->hw_scan) {
 617                 WARN_ON(!ieee80211_prep_hw_scan(local));
 618                 rc = drv_hw_scan(local, sdata, local->hw_scan_req);
 619         } else {
 620                 rc = ieee80211_start_sw_scan(local, sdata);
 621         }
 622
 623         if (rc) {
 624                 kfree(local->hw_scan_req);
 625                 local->hw_scan_req = NULL;
 626                 local->scanning = 0;
 627
 628                 ieee80211_recalc_idle(local);
 629
 630                 local->scan_req = NULL;
 631                 RCU_INIT_POINTER(local->scan_sdata, NULL);
 632         }
 633
 634         return rc;
 635 }
 636
 637 static unsigned long
 638 ieee80211_scan_get_channel_time(struct ieee80211_channel *chan)
 639 {
 640         /*
 641          * TODO: channel switching also consumes quite some time,
 642          * add that delay as well to get a better estimation
 643          */
 644         if (chan->flags & IEEE80211_CHAN_NO_IR)
 645                 return IEEE80211_PASSIVE_CHANNEL_TIME;
 646         return IEEE80211_PROBE_DELAY + IEEE80211_CHANNEL_TIME;
 647 }
 648
 649 static void ieee80211_scan_state_decision(struct ieee80211_local *local,
 650                                           unsigned long *next_delay)
 651 {
 652         bool associated = false;
 653         bool tx_empty = true;
 654         bool bad_latency;
 655         struct ieee80211_sub_if_data *sdata;
 656         struct ieee80211_channel *next_chan;
 657         enum mac80211_scan_state next_scan_state;
 658         struct cfg80211_scan_request *scan_req;
 659
 660         /*
 661          * check if at least one STA interface is associated,
 662          * check if at least one STA interface has pending tx frames
 663          * and grab the lowest used beacon interval
 664          */
 665         mutex_lock(&local->iflist_mtx);
 666         list_for_each_entry(sdata, &local->interfaces, list) {
 667                 if (!ieee80211_sdata_running(sdata))
 668                         continue;
 669
 670                 if (sdata->vif.type == NL80211_IFTYPE_STATION) {
 671                         if (sdata->u.mgd.associated) {
 672                                 associated = true;
 673
 674                                 if (!qdisc_all_tx_empty(sdata->dev)) {
 675                                         tx_empty = false;
 676                                         break;
 677                                 }
 678                         }
 679                 }
 680         }
 681         mutex_unlock(&local->iflist_mtx);
 682
 683         scan_req = rcu_dereference_protected(local->scan_req,
 684                                              lockdep_is_held(&local->mtx));
 685
 686         next_chan = scan_req->channels[local->scan_channel_idx];
 687
 688         /*
 689          * we're currently scanning a different channel, let's
 690          * see if we can scan another channel without interfering
 691          * with the current traffic situation.
 692          *
 693          * Keep good latency, do not stay off-channel more than 125 ms.
 694          */
 695
 696         bad_latency = time_after(jiffies +
 697                                  ieee80211_scan_get_channel_time(next_chan),
 698                                  local->leave_oper_channel_time + HZ / 8);
 699
 700         if (associated && !tx_empty) {
 701                 if (scan_req->flags & NL80211_SCAN_FLAG_LOW_PRIORITY)
 702                         next_scan_state = SCAN_ABORT;
 703                 else
 704                         next_scan_state = SCAN_SUSPEND;
 705         } else if (associated && bad_latency) {
 706                 next_scan_state = SCAN_SUSPEND;
 707         } else {
 708                 next_scan_state = SCAN_SET_CHANNEL;
 709         }
 710
 711         local->next_scan_state = next_scan_state;
 712
 713         *next_delay = 0;
 714 }
 715
 716 static void ieee80211_scan_state_set_channel(struct ieee80211_local *local,
 717                                              unsigned long *next_delay)
 718 {
 719         int skip;
 720         struct ieee80211_channel *chan;
 721         enum nl80211_bss_scan_width oper_scan_width;
 722         struct cfg80211_scan_request *scan_req;
 723
 724         scan_req = rcu_dereference_protected(local->scan_req,
 725                                              lockdep_is_held(&local->mtx));
 726
 727         skip = 0;
 728         chan = scan_req->channels[local->scan_channel_idx];
 729
 730         local->scan_chandef.chan = chan;
 731         local->scan_chandef.center_freq1 = chan->center_freq;
 732         local->scan_chandef.center_freq2 = 0;
 733         switch (scan_req->scan_width) {
 734         case NL80211_BSS_CHAN_WIDTH_5:
 735                 local->scan_chandef.width = NL80211_CHAN_WIDTH_5;
 736                 break;
 737         case NL80211_BSS_CHAN_WIDTH_10:
 738                 local->scan_chandef.width = NL80211_CHAN_WIDTH_10;
 739                 break;
 740         case NL80211_BSS_CHAN_WIDTH_20:
 741                 /* If scanning on oper channel, use whatever channel-type
 742                  * is currently in use.
 743                  */
 744                 oper_scan_width = cfg80211_chandef_to_scan_width(
 745                                         &local->_oper_chandef);
 746                 if (chan == local->_oper_chandef.chan &&
 747                     oper_scan_width == scan_req->scan_width)
 748                         local->scan_chandef = local->_oper_chandef;
 749                 else
 750                         local->scan_chandef.width = NL80211_CHAN_WIDTH_20_NOHT;
 751                 break;
 752         }
 753
 754         if (ieee80211_hw_config(local, IEEE80211_CONF_CHANGE_CHANNEL))
 755                 skip = 1;
 756
 757         /* advance state machine to next channel/band */
 758         local->scan_channel_idx++;
 759
 760         if (skip) {
 761                 /* if we skip this channel return to the decision state */
 762                 local->next_scan_state = SCAN_DECISION;
 763                 return;
 764         }
 765
 766         /*
 767          * Probe delay is used to update the NAV, cf. 11.1.3.2.2
 768          * (which unfortunately doesn't say _why_ step a) is done,
 769          * but it waits for the probe delay or until a frame is
 770          * received - and the received frame would update the NAV).
 771          * For now, we do not support waiting until a frame is
 772          * received.
 773          *
 774          * In any case, it is not necessary for a passive scan.
 775          */
 776         if (chan->flags & IEEE80211_CHAN_NO_IR || !scan_req->n_ssids) {
 777                 *next_delay = IEEE80211_PASSIVE_CHANNEL_TIME;
 778                 local->next_scan_state = SCAN_DECISION;
 779                 return;
 780         }
 781
 782         /* active scan, send probes */
 783         *next_delay = IEEE80211_PROBE_DELAY;
 784         local->next_scan_state = SCAN_SEND_PROBE;
 785 }
 786
 787 static void ieee80211_scan_state_suspend(struct ieee80211_local *local,
 788                                          unsigned long *next_delay)
 789 {
 790         /* switch back to the operating channel */
 791         local->scan_chandef.chan = NULL;
 792         ieee80211_hw_config(local, IEEE80211_CONF_CHANGE_CHANNEL);
 793
 794         /* disable PS */
 795         ieee80211_offchannel_return(local);
 796
 797         *next_delay = HZ / 5;
 798         /* afterwards, resume scan & go to next channel */
 799         local->next_scan_state = SCAN_RESUME;
 800 }
 801
 802 static void ieee80211_scan_state_resume(struct ieee80211_local *local,
 803                                         unsigned long *next_delay)
 804 {
 805         ieee80211_offchannel_stop_vifs(local);
 806
 807         if (local->ops->flush) {
 808                 ieee80211_flush_queues(local, NULL, false);
 809                 *next_delay = 0;
 810         } else
 811                 *next_delay = HZ / 10;
 812
 813         /* remember when we left the operating channel */
 814         local->leave_oper_channel_time = jiffies;
 815
 816         /* advance to the next channel to be scanned */
 817         local->next_scan_state = SCAN_SET_CHANNEL;
 818 }
 819
 820 void ieee80211_scan_work(struct work_struct *work)
 821 {
 822         struct ieee80211_local *local =
 823                 container_of(work, struct ieee80211_local, scan_work.work);
 824         struct ieee80211_sub_if_data *sdata;
 825         struct cfg80211_scan_request *scan_req;
 826         unsigned long next_delay = 0;
 827         bool aborted;
 828
 829         mutex_lock(&local->mtx);
 830
 831         if (!ieee80211_can_run_worker(local)) {
 832                 aborted = true;
 833                 goto out_complete;
 834         }
 835
 836         sdata = rcu_dereference_protected(local->scan_sdata,
 837                                           lockdep_is_held(&local->mtx));
 838         scan_req = rcu_dereference_protected(local->scan_req,
 839                                              lockdep_is_held(&local->mtx));
 840
 841         /* When scanning on-channel, the first-callback means completed. */
 842         if (test_bit(SCAN_ONCHANNEL_SCANNING, &local->scanning)) {
 843                 aborted = test_and_clear_bit(SCAN_ABORTED, &local->scanning);
 844                 goto out_complete;
 845         }
 846
 847         if (test_and_clear_bit(SCAN_COMPLETED, &local->scanning)) {
 848                 aborted = test_and_clear_bit(SCAN_ABORTED, &local->scanning);
 849                 goto out_complete;
 850         }
 851
 852         if (!sdata || !scan_req)
 853                 goto out;
 854
 855         if (!local->scanning) {
 856                 int rc;
 857
 858                 RCU_INIT_POINTER(local->scan_req, NULL);
 859                 RCU_INIT_POINTER(local->scan_sdata, NULL);
 860
 861                 rc = __ieee80211_start_scan(sdata, scan_req);
 862                 if (rc) {
 863                         /* need to complete scan in cfg80211 */
 864                         rcu_assign_pointer(local->scan_req, scan_req);
 865                         aborted = true;
 866                         goto out_complete;
 867                 } else
 868                         goto out;
 869         }
 870
 871         /*
 872          * as long as no delay is required advance immediately
 873          * without scheduling a new work
 874          */
 875         do {
 876                 if (!ieee80211_sdata_running(sdata)) {
 877                         aborted = true;
 878                         goto out_complete;
 879                 }
 880
 881                 switch (local->next_scan_state) {
 882                 case SCAN_DECISION:
 883                         /* if no more bands/channels left, complete scan */
 884                         if (local->scan_channel_idx >= scan_req->n_channels) {
 885                                 aborted = false;
 886                                 goto out_complete;
 887                         }
 888                         ieee80211_scan_state_decision(local, &next_delay);
 889                         break;
 890                 case SCAN_SET_CHANNEL:
 891                         ieee80211_scan_state_set_channel(local, &next_delay);
 892                         break;
 893                 case SCAN_SEND_PROBE:
 894                         ieee80211_scan_state_send_probe(local, &next_delay);
 895                         break;
 896                 case SCAN_SUSPEND:
 897                         ieee80211_scan_state_suspend(local, &next_delay);
 898                         break;
 899                 case SCAN_RESUME:
 900                         ieee80211_scan_state_resume(local, &next_delay);
 901                         break;
 902                 case SCAN_ABORT:
 903                         aborted = true;
 904                         goto out_complete;
 905                 }
 906         } while (next_delay == 0);
 907
 908         ieee80211_queue_delayed_work(&local->hw, &local->scan_work, next_delay);
 909         goto out;
 910
 911 out_complete:
 912         __ieee80211_scan_completed(&local->hw, aborted);
 913 out:
 914         mutex_unlock(&local->mtx);
 915 }
 916
 917 int ieee80211_request_scan(struct ieee80211_sub_if_data *sdata,
 918                            struct cfg80211_scan_request *req)
 919 {
 920         int res;
 921
 922         mutex_lock(&sdata->local->mtx);
 923         res = __ieee80211_start_scan(sdata, req);
 924         mutex_unlock(&sdata->local->mtx);
 925
 926         return res;
 927 }
 928
 929 int ieee80211_request_ibss_scan(struct ieee80211_sub_if_data *sdata,
 930                                 const u8 *ssid, u8 ssid_len,
 931                                 struct ieee80211_channel **channels,
 932                                 unsigned int n_channels,
 933                                 enum nl80211_bss_scan_width scan_width)
 934 {
 935         struct ieee80211_local *local = sdata->local;
 936         int ret = -EBUSY, i, n_ch = 0;
 937         enum ieee80211_band band;
 938
 939         mutex_lock(&local->mtx);
 940
 941         /* busy scanning */
 942         if (local->scan_req)
 943                 goto unlock;
 944
 945         /* fill internal scan request */
 946         if (!channels) {
 947                 int max_n;
 948
 949                 for (band = 0; band < IEEE80211_NUM_BANDS; band++) {
 950                         if (!local->hw.wiphy->bands[band])
 951                                 continue;
 952
 953                         max_n = local->hw.wiphy->bands[band]->n_channels;
 954                         for (i = 0; i < max_n; i++) {
 955                                 struct ieee80211_channel *tmp_ch =
 956                                     &local->hw.wiphy->bands[band]->channels[i];
 957
 958                                 if (tmp_ch->flags & (IEEE80211_CHAN_NO_IR |
 959                                                      IEEE80211_CHAN_DISABLED))
 960                                         continue;
 961
 962                                 local->int_scan_req->channels[n_ch] = tmp_ch;
 963                                 n_ch++;
 964                         }
 965                 }
 966
 967                 if (WARN_ON_ONCE(n_ch == 0))
 968                         goto unlock;
 969
 970                 local->int_scan_req->n_channels = n_ch;
 971         } else {
 972                 for (i = 0; i < n_channels; i++) {
 973                         if (channels[i]->flags & (IEEE80211_CHAN_NO_IR |
 974                                                   IEEE80211_CHAN_DISABLED))
 975                                 continue;
 976
 977                         local->int_scan_req->channels[n_ch] = channels[i];
 978                         n_ch++;
 979                 }
 980
 981                 if (WARN_ON_ONCE(n_ch == 0))
 982                         goto unlock;
 983
 984                 local->int_scan_req->n_channels = n_ch;
 985         }
 986
 987         local->int_scan_req->ssids = &local->scan_ssid;
 988         local->int_scan_req->n_ssids = 1;
 989         local->int_scan_req->scan_width = scan_width;
 990         memcpy(local->int_scan_req->ssids[0].ssid, ssid, IEEE80211_MAX_SSID_LEN);
 991         local->int_scan_req->ssids[0].ssid_len = ssid_len;
 992
 993         ret = __ieee80211_start_scan(sdata, sdata->local->int_scan_req);
 994  unlock:
 995         mutex_unlock(&local->mtx);
 996         return ret;
 997 }
 998
 999 /*
1000  * Only call this function when a scan can't be queued -- under RTNL.
1001  */
1002 void ieee80211_scan_cancel(struct ieee80211_local *local)
1003 {
1004         /*
1005          * We are canceling software scan, or deferred scan that was not
1006          * yet really started (see __ieee80211_start_scan ).
1007          *
1008          * Regarding hardware scan:
1009          * - we can not call  __ieee80211_scan_completed() as when
1010          *   SCAN_HW_SCANNING bit is set this function change
1011          *   local->hw_scan_req to operate on 5G band, what race with
1012          *   driver which can use local->hw_scan_req
1013          *
1014          * - we can not cancel scan_work since driver can schedule it
1015          *   by ieee80211_scan_completed(..., true) to finish scan
1016          *
1017          * Hence we only call the cancel_hw_scan() callback, but the low-level
1018          * driver is still responsible for calling ieee80211_scan_completed()
1019          * after the scan was completed/aborted.
1020          */
1021
1022         mutex_lock(&local->mtx);
1023         if (!local->scan_req)
1024                 goto out;
1025
1026         /*
1027          * We have a scan running and the driver already reported completion,
1028          * but the worker hasn't run yet or is stuck on the mutex - mark it as
1029          * cancelled.
1030          */
1031         if (test_bit(SCAN_HW_SCANNING, &local->scanning) &&
1032             test_bit(SCAN_COMPLETED, &local->scanning)) {
1033                 set_bit(SCAN_HW_CANCELLED, &local->scanning);
1034                 goto out;
1035         }
1036
1037         if (test_bit(SCAN_HW_SCANNING, &local->scanning)) {
1038                 /*
1039                  * Make sure that __ieee80211_scan_completed doesn't trigger a
1040                  * scan on another band.
1041                  */
1042                 set_bit(SCAN_HW_CANCELLED, &local->scanning);
1043                 if (local->ops->cancel_hw_scan)
1044                         drv_cancel_hw_scan(local,
1045                                 rcu_dereference_protected(local->scan_sdata,
1046                                                 lockdep_is_held(&local->mtx)));
1047                 goto out;
1048         }
1049
1050         /*
1051          * If the work is currently running, it must be blocked on
1052          * the mutex, but we'll set scan_sdata = NULL and it'll
1053          * simply exit once it acquires the mutex.
1054          */
1055         cancel_delayed_work(&local->scan_work);
1056         /* and clean up */
1057         __ieee80211_scan_completed(&local->hw, true);
1058 out:
1059         mutex_unlock(&local->mtx);
1060 }
1061
1062 int __ieee80211_request_sched_scan_start(struct ieee80211_sub_if_data *sdata,
1063                                         struct cfg80211_sched_scan_request *req)
1064 {
1065         struct ieee80211_local *local = sdata->local;
1066         struct ieee80211_scan_ies sched_scan_ies = {};
1067         struct cfg80211_chan_def chandef;
1068         int ret, i, iebufsz, num_bands = 0;
1069         u32 rate_masks[IEEE80211_NUM_BANDS] = {};
1070         u8 bands_used = 0;
1071         u8 *ie;
1072         size_t len;
1073
1074         iebufsz = local->scan_ies_len + req->ie_len;
1075
1076         lockdep_assert_held(&local->mtx);
1077
1078         if (!local->ops->sched_scan_start)
1079                 return -ENOTSUPP;
1080
1081         for (i = 0; i < IEEE80211_NUM_BANDS; i++) {
1082                 if (local->hw.wiphy->bands[i]) {
1083                         bands_used |= BIT(i);
1084                         rate_masks[i] = (u32) -1;
1085                         num_bands++;
1086                 }
1087         }
1088
1089         ie = kzalloc(num_bands * iebufsz, GFP_KERNEL);
1090         if (!ie) {
1091                 ret = -ENOMEM;
1092                 goto out;
1093         }
1094
1095         ieee80211_prepare_scan_chandef(&chandef, req->scan_width);
1096
1097         len = ieee80211_build_preq_ies(local, ie, num_bands * iebufsz,
1098                                        &sched_scan_ies, req->ie,
1099                                        req->ie_len, bands_used,
1100                                        rate_masks, &chandef);
1101
1102         ret = drv_sched_scan_start(local, sdata, req, &sched_scan_ies);
1103         if (ret == 0) {
1104                 rcu_assign_pointer(local->sched_scan_sdata, sdata);
1105                 rcu_assign_pointer(local->sched_scan_req, req);
1106         }
1107
1108         kfree(ie);
1109
1110 out:
1111         if (ret) {
1112                 /* Clean in case of failure after HW restart or upon resume. */
1113                 RCU_INIT_POINTER(local->sched_scan_sdata, NULL);
1114                 RCU_INIT_POINTER(local->sched_scan_req, NULL);
1115         }
1116
1117         return ret;
1118 }
1119
1120 int ieee80211_request_sched_scan_start(struct ieee80211_sub_if_data *sdata,
1121                                        struct cfg80211_sched_scan_request *req)
1122 {
1123         struct ieee80211_local *local = sdata->local;
1124         int ret;
1125
1126         mutex_lock(&local->mtx);
1127
1128         if (rcu_access_pointer(local->sched_scan_sdata)) {
1129                 mutex_unlock(&local->mtx);
1130                 return -EBUSY;
1131         }
1132
1133         ret = __ieee80211_request_sched_scan_start(sdata, req);
1134
1135         mutex_unlock(&local->mtx);
1136         return ret;
1137 }
1138
1139 int ieee80211_request_sched_scan_stop(struct ieee80211_sub_if_data *sdata)
1140 {
1141         struct ieee80211_local *local = sdata->local;
1142         int ret = 0;
1143
1144         mutex_lock(&local->mtx);
1145
1146         if (!local->ops->sched_scan_stop) {
1147                 ret = -ENOTSUPP;
1148                 goto out;
1149         }
1150
1151         /* We don't want to restart sched scan anymore. */
1152         RCU_INIT_POINTER(local->sched_scan_req, NULL);
1153
1154         if (rcu_access_pointer(local->sched_scan_sdata)) {
1155                 ret = drv_sched_scan_stop(local, sdata);
1156                 if (!ret)
1157                         RCU_INIT_POINTER(local->sched_scan_sdata, NULL);
1158         }
1159 out:
1160         mutex_unlock(&local->mtx);
1161
1162         return ret;
1163 }
1164
1165 void ieee80211_sched_scan_results(struct ieee80211_hw *hw)
1166 {
1167         struct ieee80211_local *local = hw_to_local(hw);
1168
1169         trace_api_sched_scan_results(local);
1170
1171         cfg80211_sched_scan_results(hw->wiphy);
1172 }
1173 EXPORT_SYMBOL(ieee80211_sched_scan_results);
1174
1175 void ieee80211_sched_scan_end(struct ieee80211_local *local)
1176 {
1177         mutex_lock(&local->mtx);
1178
1179         if (!rcu_access_pointer(local->sched_scan_sdata)) {
1180                 mutex_unlock(&local->mtx);
1181                 return;
1182         }
1183
1184         RCU_INIT_POINTER(local->sched_scan_sdata, NULL);
1185
1186         /* If sched scan was aborted by the driver. */
1187         RCU_INIT_POINTER(local->sched_scan_req, NULL);
1188
1189         mutex_unlock(&local->mtx);
1190
1191         cfg80211_sched_scan_stopped(local->hw.wiphy);
1192 }
1193
1194 void ieee80211_sched_scan_stopped_work(struct work_struct *work)
1195 {
1196         struct ieee80211_local *local =
1197                 container_of(work, struct ieee80211_local,
1198                              sched_scan_stopped_work);
1199
1200         ieee80211_sched_scan_end(local);
1201 }
1202
1203 void ieee80211_sched_scan_stopped(struct ieee80211_hw *hw)
1204 {
1205         struct ieee80211_local *local = hw_to_local(hw);
1206
1207         trace_api_sched_scan_stopped(local);
1208
1209         schedule_work(&local->sched_scan_stopped_work);
1210 }
1211 EXPORT_SYMBOL(ieee80211_sched_scan_stopped);