kernel/net/mac80211/scan.c

   1 /*
   2  * Scanning implementation
   3  *
   4  * Copyright 2003, Jouni Malinen <jkmaline@cc.hut.fi>
   5  * Copyright 2004, Instant802 Networks, Inc.
   6  * Copyright 2005, Devicescape Software, Inc.
   7  * Copyright 2006-2007  Jiri Benc <jbenc@suse.cz>
   8  * Copyright 2007, Michael Wu <flamingice@sourmilk.net>
   9  * Copyright 2013-2015  Intel Mobile Communications GmbH
  10  *
  11  * This program is free software; you can redistribute it and/or modify
  12  * it under the terms of the GNU General Public License version 2 as
  13  * published by the Free Software Foundation.
  14  */
  15
  16 #include <linux/if_arp.h>
  17 #include <linux/etherdevice.h>
  18 #include <linux/rtnetlink.h>
  19 #include <net/sch_generic.h>
  20 #include <linux/slab.h>
  21 #include <linux/export.h>
  22 #include <net/mac80211.h>
  23
  24 #include "ieee80211_i.h"
  25 #include "driver-ops.h"
  26 #include "mesh.h"
  27
  28 #define IEEE80211_PROBE_DELAY (HZ / 33)
  29 #define IEEE80211_CHANNEL_TIME (HZ / 33)
  30 #define IEEE80211_PASSIVE_CHANNEL_TIME (HZ / 9)
  31
  32 void ieee80211_rx_bss_put(struct ieee80211_local *local,
  33                           struct ieee80211_bss *bss)
  34 {
  35         if (!bss)
  36                 return;
  37         cfg80211_put_bss(local->hw.wiphy,
  38                          container_of((void *)bss, struct cfg80211_bss, priv));
  39 }
  40
  41 static bool is_uapsd_supported(struct ieee802_11_elems *elems)
  42 {
  43         u8 qos_info;
  44
  45         if (elems->wmm_info && elems->wmm_info_len == 7
  46             && elems->wmm_info[5] == 1)
  47                 qos_info = elems->wmm_info[6];
  48         else if (elems->wmm_param && elems->wmm_param_len == 24
  49                  && elems->wmm_param[5] == 1)
  50                 qos_info = elems->wmm_param[6];
  51         else
  52                 /* no valid wmm information or parameter element found */
  53                 return false;
  54
  55         return qos_info & IEEE80211_WMM_IE_AP_QOSINFO_UAPSD;
  56 }
  57
  58 struct ieee80211_bss *
  59 ieee80211_bss_info_update(struct ieee80211_local *local,
  60                           struct ieee80211_rx_status *rx_status,
  61                           struct ieee80211_mgmt *mgmt, size_t len,
  62                           struct ieee802_11_elems *elems,
  63                           struct ieee80211_channel *channel)
  64 {
  65         bool beacon = ieee80211_is_beacon(mgmt->frame_control);
  66         struct cfg80211_bss *cbss;
  67         struct ieee80211_bss *bss;
  68         int clen, srlen;
  69         struct cfg80211_inform_bss bss_meta = {};
  70         bool signal_valid;
  71
  72         if (ieee80211_hw_check(&local->hw, SIGNAL_DBM))
  73                 bss_meta.signal = rx_status->signal * 100;
  74         else if (ieee80211_hw_check(&local->hw, SIGNAL_UNSPEC))
  75                 bss_meta.signal = (rx_status->signal * 100) / local->hw.max_signal;
  76
  77         bss_meta.scan_width = NL80211_BSS_CHAN_WIDTH_20;
  78         if (rx_status->flag & RX_FLAG_5MHZ)
  79                 bss_meta.scan_width = NL80211_BSS_CHAN_WIDTH_5;
  80         if (rx_status->flag & RX_FLAG_10MHZ)
  81                 bss_meta.scan_width = NL80211_BSS_CHAN_WIDTH_10;
  82
  83         bss_meta.chan = channel;
  84         cbss = cfg80211_inform_bss_frame_data(local->hw.wiphy, &bss_meta,
  85                                               mgmt, len, GFP_ATOMIC);
  86         if (!cbss)
  87                 return NULL;
  88         /* In case the signal is invalid update the status */
  89         signal_valid = abs(channel->center_freq - cbss->channel->center_freq)
  90                 <= local->hw.wiphy->max_adj_channel_rssi_comp;
  91         if (!signal_valid)
  92                 rx_status->flag |= RX_FLAG_NO_SIGNAL_VAL;
  93
  94         bss = (void *)cbss->priv;
  95
  96         if (beacon)
  97                 bss->device_ts_beacon = rx_status->device_timestamp;
  98         else
  99                 bss->device_ts_presp = rx_status->device_timestamp;
 100
 101         if (elems->parse_error) {
 102                 if (beacon)
 103                         bss->corrupt_data |= IEEE80211_BSS_CORRUPT_BEACON;
 104                 else
 105                         bss->corrupt_data |= IEEE80211_BSS_CORRUPT_PROBE_RESP;
 106         } else {
 107                 if (beacon)
 108                         bss->corrupt_data &= ~IEEE80211_BSS_CORRUPT_BEACON;
 109                 else
 110                         bss->corrupt_data &= ~IEEE80211_BSS_CORRUPT_PROBE_RESP;
 111         }
 112
 113         /* save the ERP value so that it is available at association time */
 114         if (elems->erp_info && (!elems->parse_error ||
 115                                 !(bss->valid_data & IEEE80211_BSS_VALID_ERP))) {
 116                 bss->erp_value = elems->erp_info[0];
 117                 bss->has_erp_value = true;
 118                 if (!elems->parse_error)
 119                         bss->valid_data |= IEEE80211_BSS_VALID_ERP;
 120         }
 121
 122         /* replace old supported rates if we get new values */
 123         if (!elems->parse_error ||
 124             !(bss->valid_data & IEEE80211_BSS_VALID_RATES)) {
 125                 srlen = 0;
 126                 if (elems->supp_rates) {
 127                         clen = IEEE80211_MAX_SUPP_RATES;
 128                         if (clen > elems->supp_rates_len)
 129                                 clen = elems->supp_rates_len;
 130                         memcpy(bss->supp_rates, elems->supp_rates, clen);
 131                         srlen += clen;
 132                 }
 133                 if (elems->ext_supp_rates) {
 134                         clen = IEEE80211_MAX_SUPP_RATES - srlen;
 135                         if (clen > elems->ext_supp_rates_len)
 136                                 clen = elems->ext_supp_rates_len;
 137                         memcpy(bss->supp_rates + srlen, elems->ext_supp_rates,
 138                                clen);
 139                         srlen += clen;
 140                 }
 141                 if (srlen) {
 142                         bss->supp_rates_len = srlen;
 143                         if (!elems->parse_error)
 144                                 bss->valid_data |= IEEE80211_BSS_VALID_RATES;
 145                 }
 146         }
 147
 148         if (!elems->parse_error ||
 149             !(bss->valid_data & IEEE80211_BSS_VALID_WMM)) {
 150                 bss->wmm_used = elems->wmm_param || elems->wmm_info;
 151                 bss->uapsd_supported = is_uapsd_supported(elems);
 152                 if (!elems->parse_error)
 153                         bss->valid_data |= IEEE80211_BSS_VALID_WMM;
 154         }
 155
 156         if (beacon) {
 157                 struct ieee80211_supported_band *sband =
 158                         local->hw.wiphy->bands[rx_status->band];
 159                 if (!(rx_status->flag & RX_FLAG_HT) &&
 160                     !(rx_status->flag & RX_FLAG_VHT))
 161                         bss->beacon_rate =
 162                                 &sband->bitrates[rx_status->rate_idx];
 163         }
 164
 165         return bss;
 166 }
 167
 168 void ieee80211_scan_rx(struct ieee80211_local *local, struct sk_buff *skb)
 169 {
 170         struct ieee80211_rx_status *rx_status = IEEE80211_SKB_RXCB(skb);
 171         struct ieee80211_sub_if_data *sdata1, *sdata2;
 172         struct ieee80211_mgmt *mgmt = (void *)skb->data;
 173         struct ieee80211_bss *bss;
 174         u8 *elements;
 175         struct ieee80211_channel *channel;
 176         size_t baselen;
 177         struct ieee802_11_elems elems;
 178
 179         if (skb->len < 24 ||
 180             (!ieee80211_is_probe_resp(mgmt->frame_control) &&
 181              !ieee80211_is_beacon(mgmt->frame_control)))
 182                 return;
 183
 184         sdata1 = rcu_dereference(local->scan_sdata);
 185         sdata2 = rcu_dereference(local->sched_scan_sdata);
 186
 187         if (likely(!sdata1 && !sdata2))
 188                 return;
 189
 190         if (ieee80211_is_probe_resp(mgmt->frame_control)) {
 191                 struct cfg80211_scan_request *scan_req;
 192                 struct cfg80211_sched_scan_request *sched_scan_req;
 193
 194                 scan_req = rcu_dereference(local->scan_req);
 195                 sched_scan_req = rcu_dereference(local->sched_scan_req);
 196
 197                 /* ignore ProbeResp to foreign address unless scanning
 198                  * with randomised address
 199                  */
 200                 if (!(sdata1 &&
 201                       (ether_addr_equal(mgmt->da, sdata1->vif.addr) ||
 202                        scan_req->flags & NL80211_SCAN_FLAG_RANDOM_ADDR)) &&
 203                     !(sdata2 &&
 204                       (ether_addr_equal(mgmt->da, sdata2->vif.addr) ||
 205                        sched_scan_req->flags & NL80211_SCAN_FLAG_RANDOM_ADDR)))
 206                         return;
 207
 208                 elements = mgmt->u.probe_resp.variable;
 209                 baselen = offsetof(struct ieee80211_mgmt, u.probe_resp.variable);
 210         } else {
 211                 baselen = offsetof(struct ieee80211_mgmt, u.beacon.variable);
 212                 elements = mgmt->u.beacon.variable;
 213         }
 214
 215         if (baselen > skb->len)
 216                 return;
 217
 218         ieee802_11_parse_elems(elements, skb->len - baselen, false, &elems);
 219
 220         channel = ieee80211_get_channel(local->hw.wiphy, rx_status->freq);
 221
 222         if (!channel || channel->flags & IEEE80211_CHAN_DISABLED)
 223                 return;
 224
 225         bss = ieee80211_bss_info_update(local, rx_status,
 226                                         mgmt, skb->len, &elems,
 227                                         channel);
 228         if (bss)
 229                 ieee80211_rx_bss_put(local, bss);
 230 }
 231
 232 static void
 233 ieee80211_prepare_scan_chandef(struct cfg80211_chan_def *chandef,
 234                                enum nl80211_bss_scan_width scan_width)
 235 {
 236         memset(chandef, 0, sizeof(*chandef));
 237         switch (scan_width) {
 238         case NL80211_BSS_CHAN_WIDTH_5:
 239                 chandef->width = NL80211_CHAN_WIDTH_5;
 240                 break;
 241         case NL80211_BSS_CHAN_WIDTH_10:
 242                 chandef->width = NL80211_CHAN_WIDTH_10;
 243                 break;
 244         default:
 245                 chandef->width = NL80211_CHAN_WIDTH_20_NOHT;
 246                 break;
 247         }
 248 }
 249
 250 /* return false if no more work */
 251 static bool ieee80211_prep_hw_scan(struct ieee80211_local *local)
 252 {
 253         struct cfg80211_scan_request *req;
 254         struct cfg80211_chan_def chandef;
 255         u8 bands_used = 0;
 256         int i, ielen, n_chans;
 257
 258         req = rcu_dereference_protected(local->scan_req,
 259                                         lockdep_is_held(&local->mtx));
 260
 261         if (test_bit(SCAN_HW_CANCELLED, &local->scanning))
 262                 return false;
 263
 264         if (ieee80211_hw_check(&local->hw, SINGLE_SCAN_ON_ALL_BANDS)) {
 265                 for (i = 0; i < req->n_channels; i++) {
 266                         local->hw_scan_req->req.channels[i] = req->channels[i];
 267                         bands_used |= BIT(req->channels[i]->band);
 268                 }
 269
 270                 n_chans = req->n_channels;
 271         } else {
 272                 do {
 273                         if (local->hw_scan_band == IEEE80211_NUM_BANDS)
 274                                 return false;
 275
 276                         n_chans = 0;
 277
 278                         for (i = 0; i < req->n_channels; i++) {
 279                                 if (req->channels[i]->band !=
 280                                     local->hw_scan_band)
 281                                         continue;
 282                                 local->hw_scan_req->req.channels[n_chans] =
 283                                                         req->channels[i];
 284                                 n_chans++;
 285                                 bands_used |= BIT(req->channels[i]->band);
 286                         }
 287
 288                         local->hw_scan_band++;
 289                 } while (!n_chans);
 290         }
 291
 292         local->hw_scan_req->req.n_channels = n_chans;
 293         ieee80211_prepare_scan_chandef(&chandef, req->scan_width);
 294
 295         ielen = ieee80211_build_preq_ies(local,
 296                                          (u8 *)local->hw_scan_req->req.ie,
 297                                          local->hw_scan_ies_bufsize,
 298                                          &local->hw_scan_req->ies,
 299                                          req->ie, req->ie_len,
 300                                          bands_used, req->rates, &chandef);
 301         local->hw_scan_req->req.ie_len = ielen;
 302         local->hw_scan_req->req.no_cck = req->no_cck;
 303         ether_addr_copy(local->hw_scan_req->req.mac_addr, req->mac_addr);
 304         ether_addr_copy(local->hw_scan_req->req.mac_addr_mask,
 305                         req->mac_addr_mask);
 306
 307         return true;
 308 }
 309
 310 static void __ieee80211_scan_completed(struct ieee80211_hw *hw, bool aborted)
 311 {
 312         struct ieee80211_local *local = hw_to_local(hw);
 313         bool hw_scan = local->ops->hw_scan;
 314         bool was_scanning = local->scanning;
 315         struct cfg80211_scan_request *scan_req;
 316         struct ieee80211_sub_if_data *scan_sdata;
 317         struct ieee80211_sub_if_data *sdata;
 318
 319         lockdep_assert_held(&local->mtx);
 320
 321         /*
 322          * It's ok to abort a not-yet-running scan (that
 323          * we have one at all will be verified by checking
 324          * local->scan_req next), but not to complete it
 325          * successfully.
 326          */
 327         if (WARN_ON(!local->scanning && !aborted))
 328                 aborted = true;
 329
 330         if (WARN_ON(!local->scan_req))
 331                 return;
 332
 333         if (hw_scan && !aborted &&
 334             !ieee80211_hw_check(&local->hw, SINGLE_SCAN_ON_ALL_BANDS) &&
 335             ieee80211_prep_hw_scan(local)) {
 336                 int rc;
 337
 338                 rc = drv_hw_scan(local,
 339                         rcu_dereference_protected(local->scan_sdata,
 340                                                   lockdep_is_held(&local->mtx)),
 341                         local->hw_scan_req);
 342
 343                 if (rc == 0)
 344                         return;
 345         }
 346
 347         kfree(local->hw_scan_req);
 348         local->hw_scan_req = NULL;
 349
 350         scan_req = rcu_dereference_protected(local->scan_req,
 351                                              lockdep_is_held(&local->mtx));
 352
 353         if (scan_req != local->int_scan_req)
 354                 cfg80211_scan_done(scan_req, aborted);
 355         RCU_INIT_POINTER(local->scan_req, NULL);
 356
 357         scan_sdata = rcu_dereference_protected(local->scan_sdata,
 358                                                lockdep_is_held(&local->mtx));
 359         RCU_INIT_POINTER(local->scan_sdata, NULL);
 360
 361         local->scanning = 0;
 362         local->scan_chandef.chan = NULL;
 363
 364         /* Set power back to normal operating levels. */
 365         ieee80211_hw_config(local, 0);
 366
 367         if (!hw_scan) {
 368                 ieee80211_configure_filter(local);
 369                 drv_sw_scan_complete(local, scan_sdata);
 370                 ieee80211_offchannel_return(local);
 371         }
 372
 373         ieee80211_recalc_idle(local);
 374
 375         ieee80211_mlme_notify_scan_completed(local);
 376         ieee80211_ibss_notify_scan_completed(local);
 377
 378         /* Requeue all the work that might have been ignored while
 379          * the scan was in progress; if there was none this will
 380          * just be a no-op for the particular interface.
 381          */
 382         list_for_each_entry_rcu(sdata, &local->interfaces, list) {
 383                 if (ieee80211_sdata_running(sdata))
 384                         ieee80211_queue_work(&sdata->local->hw, &sdata->work);
 385         }
 386
 387         if (was_scanning)
 388                 ieee80211_start_next_roc(local);
 389 }
 390
 391 void ieee80211_scan_completed(struct ieee80211_hw *hw, bool aborted)
 392 {
 393         struct ieee80211_local *local = hw_to_local(hw);
 394
 395         trace_api_scan_completed(local, aborted);
 396
 397         set_bit(SCAN_COMPLETED, &local->scanning);
 398         if (aborted)
 399                 set_bit(SCAN_ABORTED, &local->scanning);
 400         ieee80211_queue_delayed_work(&local->hw, &local->scan_work, 0);
 401 }
 402 EXPORT_SYMBOL(ieee80211_scan_completed);
 403
 404 static int ieee80211_start_sw_scan(struct ieee80211_local *local,
 405                                    struct ieee80211_sub_if_data *sdata)
 406 {
 407         /* Software scan is not supported in multi-channel cases */
 408         if (local->use_chanctx)
 409                 return -EOPNOTSUPP;
 410
 411         /*
 412          * Hardware/driver doesn't support hw_scan, so use software
 413          * scanning instead. First send a nullfunc frame with power save
 414          * bit on so that AP will buffer the frames for us while we are not
 415          * listening, then send probe requests to each channel and wait for
 416          * the responses. After all channels are scanned, tune back to the
 417          * original channel and send a nullfunc frame with power save bit
 418          * off to trigger the AP to send us all the buffered frames.
 419          *
 420          * Note that while local->sw_scanning is true everything else but
 421          * nullfunc frames and probe requests will be dropped in
 422          * ieee80211_tx_h_check_assoc().
 423          */
 424         drv_sw_scan_start(local, sdata, local->scan_addr);
 425
 426         local->leave_oper_channel_time = jiffies;
 427         local->next_scan_state = SCAN_DECISION;
 428         local->scan_channel_idx = 0;
 429
 430         ieee80211_offchannel_stop_vifs(local);
 431
 432         /* ensure nullfunc is transmitted before leaving operating channel */
 433         ieee80211_flush_queues(local, NULL, false);
 434
 435         ieee80211_configure_filter(local);
 436
 437         /* We need to set power level at maximum rate for scanning. */
 438         ieee80211_hw_config(local, 0);
 439
 440         ieee80211_queue_delayed_work(&local->hw,
 441                                      &local->scan_work, 0);
 442
 443         return 0;
 444 }
 445
 446 static bool ieee80211_can_scan(struct ieee80211_local *local,
 447                                struct ieee80211_sub_if_data *sdata)
 448 {
 449         if (ieee80211_is_radar_required(local))
 450                 return false;
 451
 452         if (!list_empty(&local->roc_list))
 453                 return false;
 454
 455         if (sdata->vif.type == NL80211_IFTYPE_STATION &&
 456             sdata->u.mgd.flags & IEEE80211_STA_CONNECTION_POLL)
 457                 return false;
 458
 459         return true;
 460 }
 461
 462 void ieee80211_run_deferred_scan(struct ieee80211_local *local)
 463 {
 464         lockdep_assert_held(&local->mtx);
 465
 466         if (!local->scan_req || local->scanning)
 467                 return;
 468
 469         if (!ieee80211_can_scan(local,
 470                                 rcu_dereference_protected(
 471                                         local->scan_sdata,
 472                                         lockdep_is_held(&local->mtx))))
 473                 return;
 474
 475         ieee80211_queue_delayed_work(&local->hw, &local->scan_work,
 476                                      round_jiffies_relative(0));
 477 }
 478
 479 static void ieee80211_scan_state_send_probe(struct ieee80211_local *local,
 480                                             unsigned long *next_delay)
 481 {
 482         int i;
 483         struct ieee80211_sub_if_data *sdata;
 484         struct cfg80211_scan_request *scan_req;
 485         enum ieee80211_band band = local->hw.conf.chandef.chan->band;
 486         u32 tx_flags;
 487
 488         scan_req = rcu_dereference_protected(local->scan_req,
 489                                              lockdep_is_held(&local->mtx));
 490
 491         tx_flags = IEEE80211_TX_INTFL_OFFCHAN_TX_OK;
 492         if (scan_req->no_cck)
 493                 tx_flags |= IEEE80211_TX_CTL_NO_CCK_RATE;
 494
 495         sdata = rcu_dereference_protected(local->scan_sdata,
 496                                           lockdep_is_held(&local->mtx));
 497
 498         for (i = 0; i < scan_req->n_ssids; i++)
 499                 ieee80211_send_probe_req(
 500                         sdata, local->scan_addr, NULL,
 501                         scan_req->ssids[i].ssid, scan_req->ssids[i].ssid_len,
 502                         scan_req->ie, scan_req->ie_len,
 503                         scan_req->rates[band], false,
 504                         tx_flags, local->hw.conf.chandef.chan, true);
 505
 506         /*
 507          * After sending probe requests, wait for probe responses
 508          * on the channel.
 509          */
 510         *next_delay = IEEE80211_CHANNEL_TIME;
 511         local->next_scan_state = SCAN_DECISION;
 512 }
 513
 514 static int __ieee80211_start_scan(struct ieee80211_sub_if_data *sdata,
 515                                   struct cfg80211_scan_request *req)
 516 {
 517         struct ieee80211_local *local = sdata->local;
 518         int rc;
 519
 520         lockdep_assert_held(&local->mtx);
 521
 522         if (local->scan_req || ieee80211_is_radar_required(local))
 523                 return -EBUSY;
 524
 525         if (!ieee80211_can_scan(local, sdata)) {
 526                 /* wait for the work to finish/time out */
 527                 rcu_assign_pointer(local->scan_req, req);
 528                 rcu_assign_pointer(local->scan_sdata, sdata);
 529                 return 0;
 530         }
 531
 532         if (local->ops->hw_scan) {
 533                 u8 *ies;
 534
 535                 local->hw_scan_ies_bufsize = local->scan_ies_len + req->ie_len;
 536
 537                 if (ieee80211_hw_check(&local->hw, SINGLE_SCAN_ON_ALL_BANDS)) {
 538                         int i, n_bands = 0;
 539                         u8 bands_counted = 0;
 540
 541                         for (i = 0; i < req->n_channels; i++) {
 542                                 if (bands_counted & BIT(req->channels[i]->band))
 543                                         continue;
 544                                 bands_counted |= BIT(req->channels[i]->band);
 545                                 n_bands++;
 546                         }
 547
 548                         local->hw_scan_ies_bufsize *= n_bands;
 549                 }
 550
 551                 local->hw_scan_req = kmalloc(
 552                                 sizeof(*local->hw_scan_req) +
 553                                 req->n_channels * sizeof(req->channels[0]) +
 554                                 local->hw_scan_ies_bufsize, GFP_KERNEL);
 555                 if (!local->hw_scan_req)
 556                         return -ENOMEM;
 557
 558                 local->hw_scan_req->req.ssids = req->ssids;
 559                 local->hw_scan_req->req.n_ssids = req->n_ssids;
 560                 ies = (u8 *)local->hw_scan_req +
 561                         sizeof(*local->hw_scan_req) +
 562                         req->n_channels * sizeof(req->channels[0]);
 563                 local->hw_scan_req->req.ie = ies;
 564                 local->hw_scan_req->req.flags = req->flags;
 565
 566                 local->hw_scan_band = 0;
 567
 568                 /*
 569                  * After allocating local->hw_scan_req, we must
 570                  * go through until ieee80211_prep_hw_scan(), so
 571                  * anything that might be changed here and leave
 572                  * this function early must not go after this
 573                  * allocation.
 574                  */
 575         }
 576
 577         rcu_assign_pointer(local->scan_req, req);
 578         rcu_assign_pointer(local->scan_sdata, sdata);
 579
 580         if (req->flags & NL80211_SCAN_FLAG_RANDOM_ADDR)
 581                 get_random_mask_addr(local->scan_addr,
 582                                      req->mac_addr,
 583                                      req->mac_addr_mask);
 584         else
 585                 memcpy(local->scan_addr, sdata->vif.addr, ETH_ALEN);
 586
 587         if (local->ops->hw_scan) {
 588                 __set_bit(SCAN_HW_SCANNING, &local->scanning);
 589         } else if ((req->n_channels == 1) &&
 590                    (req->channels[0] == local->_oper_chandef.chan)) {
 591                 /*
 592                  * If we are scanning only on the operating channel
 593                  * then we do not need to stop normal activities
 594                  */
 595                 unsigned long next_delay;
 596
 597                 __set_bit(SCAN_ONCHANNEL_SCANNING, &local->scanning);
 598
 599                 ieee80211_recalc_idle(local);
 600
 601                 /* Notify driver scan is starting, keep order of operations
 602                  * same as normal software scan, in case that matters. */
 603                 drv_sw_scan_start(local, sdata, local->scan_addr);
 604
 605                 ieee80211_configure_filter(local); /* accept probe-responses */
 606
 607                 /* We need to ensure power level is at max for scanning. */
 608                 ieee80211_hw_config(local, 0);
 609
 610                 if ((req->channels[0]->flags & (IEEE80211_CHAN_NO_IR |
 611                                                 IEEE80211_CHAN_RADAR)) ||
 612                     !req->n_ssids) {
 613                         next_delay = IEEE80211_PASSIVE_CHANNEL_TIME;
 614                 } else {
 615                         ieee80211_scan_state_send_probe(local, &next_delay);
 616                         next_delay = IEEE80211_CHANNEL_TIME;
 617                 }
 618
 619                 /* Now, just wait a bit and we are all done! */
 620                 ieee80211_queue_delayed_work(&local->hw, &local->scan_work,
 621                                              next_delay);
 622                 return 0;
 623         } else {
 624                 /* Do normal software scan */
 625                 __set_bit(SCAN_SW_SCANNING, &local->scanning);
 626         }
 627
 628         ieee80211_recalc_idle(local);
 629
 630         if (local->ops->hw_scan) {
 631                 WARN_ON(!ieee80211_prep_hw_scan(local));
 632                 rc = drv_hw_scan(local, sdata, local->hw_scan_req);
 633         } else {
 634                 rc = ieee80211_start_sw_scan(local, sdata);
 635         }
 636
 637         if (rc) {
 638                 kfree(local->hw_scan_req);
 639                 local->hw_scan_req = NULL;
 640                 local->scanning = 0;
 641
 642                 ieee80211_recalc_idle(local);
 643
 644                 local->scan_req = NULL;
 645                 RCU_INIT_POINTER(local->scan_sdata, NULL);
 646         }
 647
 648         return rc;
 649 }
 650
 651 static unsigned long
 652 ieee80211_scan_get_channel_time(struct ieee80211_channel *chan)
 653 {
 654         /*
 655          * TODO: channel switching also consumes quite some time,
 656          * add that delay as well to get a better estimation
 657          */
 658         if (chan->flags & (IEEE80211_CHAN_NO_IR | IEEE80211_CHAN_RADAR))
 659                 return IEEE80211_PASSIVE_CHANNEL_TIME;
 660         return IEEE80211_PROBE_DELAY + IEEE80211_CHANNEL_TIME;
 661 }
 662
 663 static void ieee80211_scan_state_decision(struct ieee80211_local *local,
 664                                           unsigned long *next_delay)
 665 {
 666         bool associated = false;
 667         bool tx_empty = true;
 668         bool bad_latency;
 669         struct ieee80211_sub_if_data *sdata;
 670         struct ieee80211_channel *next_chan;
 671         enum mac80211_scan_state next_scan_state;
 672         struct cfg80211_scan_request *scan_req;
 673
 674         /*
 675          * check if at least one STA interface is associated,
 676          * check if at least one STA interface has pending tx frames
 677          * and grab the lowest used beacon interval
 678          */
 679         mutex_lock(&local->iflist_mtx);
 680         list_for_each_entry(sdata, &local->interfaces, list) {
 681                 if (!ieee80211_sdata_running(sdata))
 682                         continue;
 683
 684                 if (sdata->vif.type == NL80211_IFTYPE_STATION) {
 685                         if (sdata->u.mgd.associated) {
 686                                 associated = true;
 687
 688                                 if (!qdisc_all_tx_empty(sdata->dev)) {
 689                                         tx_empty = false;
 690                                         break;
 691                                 }
 692                         }
 693                 }
 694         }
 695         mutex_unlock(&local->iflist_mtx);
 696
 697         scan_req = rcu_dereference_protected(local->scan_req,
 698                                              lockdep_is_held(&local->mtx));
 699
 700         next_chan = scan_req->channels[local->scan_channel_idx];
 701
 702         /*
 703          * we're currently scanning a different channel, let's
 704          * see if we can scan another channel without interfering
 705          * with the current traffic situation.
 706          *
 707          * Keep good latency, do not stay off-channel more than 125 ms.
 708          */
 709
 710         bad_latency = time_after(jiffies +
 711                                  ieee80211_scan_get_channel_time(next_chan),
 712                                  local->leave_oper_channel_time + HZ / 8);
 713
 714         if (associated && !tx_empty) {
 715                 if (scan_req->flags & NL80211_SCAN_FLAG_LOW_PRIORITY)
 716                         next_scan_state = SCAN_ABORT;
 717                 else
 718                         next_scan_state = SCAN_SUSPEND;
 719         } else if (associated && bad_latency) {
 720                 next_scan_state = SCAN_SUSPEND;
 721         } else {
 722                 next_scan_state = SCAN_SET_CHANNEL;
 723         }
 724
 725         local->next_scan_state = next_scan_state;
 726
 727         *next_delay = 0;
 728 }
 729
 730 static void ieee80211_scan_state_set_channel(struct ieee80211_local *local,
 731                                              unsigned long *next_delay)
 732 {
 733         int skip;
 734         struct ieee80211_channel *chan;
 735         enum nl80211_bss_scan_width oper_scan_width;
 736         struct cfg80211_scan_request *scan_req;
 737
 738         scan_req = rcu_dereference_protected(local->scan_req,
 739                                              lockdep_is_held(&local->mtx));
 740
 741         skip = 0;
 742         chan = scan_req->channels[local->scan_channel_idx];
 743
 744         local->scan_chandef.chan = chan;
 745         local->scan_chandef.center_freq1 = chan->center_freq;
 746         local->scan_chandef.center_freq2 = 0;
 747         switch (scan_req->scan_width) {
 748         case NL80211_BSS_CHAN_WIDTH_5:
 749                 local->scan_chandef.width = NL80211_CHAN_WIDTH_5;
 750                 break;
 751         case NL80211_BSS_CHAN_WIDTH_10:
 752                 local->scan_chandef.width = NL80211_CHAN_WIDTH_10;
 753                 break;
 754         case NL80211_BSS_CHAN_WIDTH_20:
 755                 /* If scanning on oper channel, use whatever channel-type
 756                  * is currently in use.
 757                  */
 758                 oper_scan_width = cfg80211_chandef_to_scan_width(
 759                                         &local->_oper_chandef);
 760                 if (chan == local->_oper_chandef.chan &&
 761                     oper_scan_width == scan_req->scan_width)
 762                         local->scan_chandef = local->_oper_chandef;
 763                 else
 764                         local->scan_chandef.width = NL80211_CHAN_WIDTH_20_NOHT;
 765                 break;
 766         }
 767
 768         if (ieee80211_hw_config(local, IEEE80211_CONF_CHANGE_CHANNEL))
 769                 skip = 1;
 770
 771         /* advance state machine to next channel/band */
 772         local->scan_channel_idx++;
 773
 774         if (skip) {
 775                 /* if we skip this channel return to the decision state */
 776                 local->next_scan_state = SCAN_DECISION;
 777                 return;
 778         }
 779
 780         /*
 781          * Probe delay is used to update the NAV, cf. 11.1.3.2.2
 782          * (which unfortunately doesn't say _why_ step a) is done,
 783          * but it waits for the probe delay or until a frame is
 784          * received - and the received frame would update the NAV).
 785          * For now, we do not support waiting until a frame is
 786          * received.
 787          *
 788          * In any case, it is not necessary for a passive scan.
 789          */
 790         if ((chan->flags & (IEEE80211_CHAN_NO_IR | IEEE80211_CHAN_RADAR)) ||
 791             !scan_req->n_ssids) {
 792                 *next_delay = IEEE80211_PASSIVE_CHANNEL_TIME;
 793                 local->next_scan_state = SCAN_DECISION;
 794                 return;
 795         }
 796
 797         /* active scan, send probes */
 798         *next_delay = IEEE80211_PROBE_DELAY;
 799         local->next_scan_state = SCAN_SEND_PROBE;
 800 }
 801
 802 static void ieee80211_scan_state_suspend(struct ieee80211_local *local,
 803                                          unsigned long *next_delay)
 804 {
 805         /* switch back to the operating channel */
 806         local->scan_chandef.chan = NULL;
 807         ieee80211_hw_config(local, IEEE80211_CONF_CHANGE_CHANNEL);
 808
 809         /* disable PS */
 810         ieee80211_offchannel_return(local);
 811
 812         *next_delay = HZ / 5;
 813         /* afterwards, resume scan & go to next channel */
 814         local->next_scan_state = SCAN_RESUME;
 815 }
 816
 817 static void ieee80211_scan_state_resume(struct ieee80211_local *local,
 818                                         unsigned long *next_delay)
 819 {
 820         ieee80211_offchannel_stop_vifs(local);
 821
 822         if (local->ops->flush) {
 823                 ieee80211_flush_queues(local, NULL, false);
 824                 *next_delay = 0;
 825         } else
 826                 *next_delay = HZ / 10;
 827
 828         /* remember when we left the operating channel */
 829         local->leave_oper_channel_time = jiffies;
 830
 831         /* advance to the next channel to be scanned */
 832         local->next_scan_state = SCAN_SET_CHANNEL;
 833 }
 834
 835 void ieee80211_scan_work(struct work_struct *work)
 836 {
 837         struct ieee80211_local *local =
 838                 container_of(work, struct ieee80211_local, scan_work.work);
 839         struct ieee80211_sub_if_data *sdata;
 840         struct cfg80211_scan_request *scan_req;
 841         unsigned long next_delay = 0;
 842         bool aborted;
 843
 844         mutex_lock(&local->mtx);
 845
 846         if (!ieee80211_can_run_worker(local)) {
 847                 aborted = true;
 848                 goto out_complete;
 849         }
 850
 851         sdata = rcu_dereference_protected(local->scan_sdata,
 852                                           lockdep_is_held(&local->mtx));
 853         scan_req = rcu_dereference_protected(local->scan_req,
 854                                              lockdep_is_held(&local->mtx));
 855
 856         /* When scanning on-channel, the first-callback means completed. */
 857         if (test_bit(SCAN_ONCHANNEL_SCANNING, &local->scanning)) {
 858                 aborted = test_and_clear_bit(SCAN_ABORTED, &local->scanning);
 859                 goto out_complete;
 860         }
 861
 862         if (test_and_clear_bit(SCAN_COMPLETED, &local->scanning)) {
 863                 aborted = test_and_clear_bit(SCAN_ABORTED, &local->scanning);
 864                 goto out_complete;
 865         }
 866
 867         if (!sdata || !scan_req)
 868                 goto out;
 869
 870         if (!local->scanning) {
 871                 int rc;
 872
 873                 RCU_INIT_POINTER(local->scan_req, NULL);
 874                 RCU_INIT_POINTER(local->scan_sdata, NULL);
 875
 876                 rc = __ieee80211_start_scan(sdata, scan_req);
 877                 if (rc) {
 878                         /* need to complete scan in cfg80211 */
 879                         rcu_assign_pointer(local->scan_req, scan_req);
 880                         aborted = true;
 881                         goto out_complete;
 882                 } else
 883                         goto out;
 884         }
 885
 886         /*
 887          * as long as no delay is required advance immediately
 888          * without scheduling a new work
 889          */
 890         do {
 891                 if (!ieee80211_sdata_running(sdata)) {
 892                         aborted = true;
 893                         goto out_complete;
 894                 }
 895
 896                 switch (local->next_scan_state) {
 897                 case SCAN_DECISION:
 898                         /* if no more bands/channels left, complete scan */
 899                         if (local->scan_channel_idx >= scan_req->n_channels) {
 900                                 aborted = false;
 901                                 goto out_complete;
 902                         }
 903                         ieee80211_scan_state_decision(local, &next_delay);
 904                         break;
 905                 case SCAN_SET_CHANNEL:
 906                         ieee80211_scan_state_set_channel(local, &next_delay);
 907                         break;
 908                 case SCAN_SEND_PROBE:
 909                         ieee80211_scan_state_send_probe(local, &next_delay);
 910                         break;
 911                 case SCAN_SUSPEND:
 912                         ieee80211_scan_state_suspend(local, &next_delay);
 913                         break;
 914                 case SCAN_RESUME:
 915                         ieee80211_scan_state_resume(local, &next_delay);
 916                         break;
 917                 case SCAN_ABORT:
 918                         aborted = true;
 919                         goto out_complete;
 920                 }
 921         } while (next_delay == 0);
 922
 923         ieee80211_queue_delayed_work(&local->hw, &local->scan_work, next_delay);
 924         goto out;
 925
 926 out_complete:
 927         __ieee80211_scan_completed(&local->hw, aborted);
 928 out:
 929         mutex_unlock(&local->mtx);
 930 }
 931
 932 int ieee80211_request_scan(struct ieee80211_sub_if_data *sdata,
 933                            struct cfg80211_scan_request *req)
 934 {
 935         int res;
 936
 937         mutex_lock(&sdata->local->mtx);
 938         res = __ieee80211_start_scan(sdata, req);
 939         mutex_unlock(&sdata->local->mtx);
 940
 941         return res;
 942 }
 943
 944 int ieee80211_request_ibss_scan(struct ieee80211_sub_if_data *sdata,
 945                                 const u8 *ssid, u8 ssid_len,
 946                                 struct ieee80211_channel **channels,
 947                                 unsigned int n_channels,
 948                                 enum nl80211_bss_scan_width scan_width)
 949 {
 950         struct ieee80211_local *local = sdata->local;
 951         int ret = -EBUSY, i, n_ch = 0;
 952         enum ieee80211_band band;
 953
 954         mutex_lock(&local->mtx);
 955
 956         /* busy scanning */
 957         if (local->scan_req)
 958                 goto unlock;
 959
 960         /* fill internal scan request */
 961         if (!channels) {
 962                 int max_n;
 963
 964                 for (band = 0; band < IEEE80211_NUM_BANDS; band++) {
 965                         if (!local->hw.wiphy->bands[band])
 966                                 continue;
 967
 968                         max_n = local->hw.wiphy->bands[band]->n_channels;
 969                         for (i = 0; i < max_n; i++) {
 970                                 struct ieee80211_channel *tmp_ch =
 971                                     &local->hw.wiphy->bands[band]->channels[i];
 972
 973                                 if (tmp_ch->flags & (IEEE80211_CHAN_NO_IR |
 974                                                      IEEE80211_CHAN_DISABLED))
 975                                         continue;
 976
 977                                 local->int_scan_req->channels[n_ch] = tmp_ch;
 978                                 n_ch++;
 979                         }
 980                 }
 981
 982                 if (WARN_ON_ONCE(n_ch == 0))
 983                         goto unlock;
 984
 985                 local->int_scan_req->n_channels = n_ch;
 986         } else {
 987                 for (i = 0; i < n_channels; i++) {
 988                         if (channels[i]->flags & (IEEE80211_CHAN_NO_IR |
 989                                                   IEEE80211_CHAN_DISABLED))
 990                                 continue;
 991
 992                         local->int_scan_req->channels[n_ch] = channels[i];
 993                         n_ch++;
 994                 }
 995
 996                 if (WARN_ON_ONCE(n_ch == 0))
 997                         goto unlock;
 998
 999                 local->int_scan_req->n_channels = n_ch;
1000         }
1001
1002         local->int_scan_req->ssids = &local->scan_ssid;
1003         local->int_scan_req->n_ssids = 1;
1004         local->int_scan_req->scan_width = scan_width;
1005         memcpy(local->int_scan_req->ssids[0].ssid, ssid, IEEE80211_MAX_SSID_LEN);
1006         local->int_scan_req->ssids[0].ssid_len = ssid_len;
1007
1008         ret = __ieee80211_start_scan(sdata, sdata->local->int_scan_req);
1009  unlock:
1010         mutex_unlock(&local->mtx);
1011         return ret;
1012 }
1013
1014 /*
1015  * Only call this function when a scan can't be queued -- under RTNL.
1016  */
1017 void ieee80211_scan_cancel(struct ieee80211_local *local)
1018 {
1019         /*
1020          * We are canceling software scan, or deferred scan that was not
1021          * yet really started (see __ieee80211_start_scan ).
1022          *
1023          * Regarding hardware scan:
1024          * - we can not call  __ieee80211_scan_completed() as when
1025          *   SCAN_HW_SCANNING bit is set this function change
1026          *   local->hw_scan_req to operate on 5G band, what race with
1027          *   driver which can use local->hw_scan_req
1028          *
1029          * - we can not cancel scan_work since driver can schedule it
1030          *   by ieee80211_scan_completed(..., true) to finish scan
1031          *
1032          * Hence we only call the cancel_hw_scan() callback, but the low-level
1033          * driver is still responsible for calling ieee80211_scan_completed()
1034          * after the scan was completed/aborted.
1035          */
1036
1037         mutex_lock(&local->mtx);
1038         if (!local->scan_req)
1039                 goto out;
1040
1041         /*
1042          * We have a scan running and the driver already reported completion,
1043          * but the worker hasn't run yet or is stuck on the mutex - mark it as
1044          * cancelled.
1045          */
1046         if (test_bit(SCAN_HW_SCANNING, &local->scanning) &&
1047             test_bit(SCAN_COMPLETED, &local->scanning)) {
1048                 set_bit(SCAN_HW_CANCELLED, &local->scanning);
1049                 goto out;
1050         }
1051
1052         if (test_bit(SCAN_HW_SCANNING, &local->scanning)) {
1053                 /*
1054                  * Make sure that __ieee80211_scan_completed doesn't trigger a
1055                  * scan on another band.
1056                  */
1057                 set_bit(SCAN_HW_CANCELLED, &local->scanning);
1058                 if (local->ops->cancel_hw_scan)
1059                         drv_cancel_hw_scan(local,
1060                                 rcu_dereference_protected(local->scan_sdata,
1061                                                 lockdep_is_held(&local->mtx)));
1062                 goto out;
1063         }
1064
1065         /*
1066          * If the work is currently running, it must be blocked on
1067          * the mutex, but we'll set scan_sdata = NULL and it'll
1068          * simply exit once it acquires the mutex.
1069          */
1070         cancel_delayed_work(&local->scan_work);
1071         /* and clean up */
1072         __ieee80211_scan_completed(&local->hw, true);
1073 out:
1074         mutex_unlock(&local->mtx);
1075 }
1076
1077 int __ieee80211_request_sched_scan_start(struct ieee80211_sub_if_data *sdata,
1078                                         struct cfg80211_sched_scan_request *req)
1079 {
1080         struct ieee80211_local *local = sdata->local;
1081         struct ieee80211_scan_ies sched_scan_ies = {};
1082         struct cfg80211_chan_def chandef;
1083         int ret, i, iebufsz, num_bands = 0;
1084         u32 rate_masks[IEEE80211_NUM_BANDS] = {};
1085         u8 bands_used = 0;
1086         u8 *ie;
1087         size_t len;
1088
1089         iebufsz = local->scan_ies_len + req->ie_len;
1090
1091         lockdep_assert_held(&local->mtx);
1092
1093         if (!local->ops->sched_scan_start)
1094                 return -ENOTSUPP;
1095
1096         for (i = 0; i < IEEE80211_NUM_BANDS; i++) {
1097                 if (local->hw.wiphy->bands[i]) {
1098                         bands_used |= BIT(i);
1099                         rate_masks[i] = (u32) -1;
1100                         num_bands++;
1101                 }
1102         }
1103
1104         ie = kzalloc(num_bands * iebufsz, GFP_KERNEL);
1105         if (!ie) {
1106                 ret = -ENOMEM;
1107                 goto out;
1108         }
1109
1110         ieee80211_prepare_scan_chandef(&chandef, req->scan_width);
1111
1112         len = ieee80211_build_preq_ies(local, ie, num_bands * iebufsz,
1113                                        &sched_scan_ies, req->ie,
1114                                        req->ie_len, bands_used,
1115                                        rate_masks, &chandef);
1116
1117         ret = drv_sched_scan_start(local, sdata, req, &sched_scan_ies);
1118         if (ret == 0) {
1119                 rcu_assign_pointer(local->sched_scan_sdata, sdata);
1120                 rcu_assign_pointer(local->sched_scan_req, req);
1121         }
1122
1123         kfree(ie);
1124
1125 out:
1126         if (ret) {
1127                 /* Clean in case of failure after HW restart or upon resume. */
1128                 RCU_INIT_POINTER(local->sched_scan_sdata, NULL);
1129                 RCU_INIT_POINTER(local->sched_scan_req, NULL);
1130         }
1131
1132         return ret;
1133 }
1134
1135 int ieee80211_request_sched_scan_start(struct ieee80211_sub_if_data *sdata,
1136                                        struct cfg80211_sched_scan_request *req)
1137 {
1138         struct ieee80211_local *local = sdata->local;
1139         int ret;
1140
1141         mutex_lock(&local->mtx);
1142
1143         if (rcu_access_pointer(local->sched_scan_sdata)) {
1144                 mutex_unlock(&local->mtx);
1145                 return -EBUSY;
1146         }
1147
1148         ret = __ieee80211_request_sched_scan_start(sdata, req);
1149
1150         mutex_unlock(&local->mtx);
1151         return ret;
1152 }
1153
1154 int ieee80211_request_sched_scan_stop(struct ieee80211_local *local)
1155 {
1156         struct ieee80211_sub_if_data *sched_scan_sdata;
1157         int ret = -ENOENT;
1158
1159         mutex_lock(&local->mtx);
1160
1161         if (!local->ops->sched_scan_stop) {
1162                 ret = -ENOTSUPP;
1163                 goto out;
1164         }
1165
1166         /* We don't want to restart sched scan anymore. */
1167         RCU_INIT_POINTER(local->sched_scan_req, NULL);
1168
1169         sched_scan_sdata = rcu_dereference_protected(local->sched_scan_sdata,
1170                                                 lockdep_is_held(&local->mtx));
1171         if (sched_scan_sdata) {
1172                 ret = drv_sched_scan_stop(local, sched_scan_sdata);
1173                 if (!ret)
1174                         RCU_INIT_POINTER(local->sched_scan_sdata, NULL);
1175         }
1176 out:
1177         mutex_unlock(&local->mtx);
1178
1179         return ret;
1180 }
1181
1182 void ieee80211_sched_scan_results(struct ieee80211_hw *hw)
1183 {
1184         struct ieee80211_local *local = hw_to_local(hw);
1185
1186         trace_api_sched_scan_results(local);
1187
1188         cfg80211_sched_scan_results(hw->wiphy);
1189 }
1190 EXPORT_SYMBOL(ieee80211_sched_scan_results);
1191
1192 void ieee80211_sched_scan_end(struct ieee80211_local *local)
1193 {
1194         mutex_lock(&local->mtx);
1195
1196         if (!rcu_access_pointer(local->sched_scan_sdata)) {
1197                 mutex_unlock(&local->mtx);
1198                 return;
1199         }
1200
1201         RCU_INIT_POINTER(local->sched_scan_sdata, NULL);
1202
1203         /* If sched scan was aborted by the driver. */
1204         RCU_INIT_POINTER(local->sched_scan_req, NULL);
1205
1206         mutex_unlock(&local->mtx);
1207
1208         cfg80211_sched_scan_stopped(local->hw.wiphy);
1209 }
1210
1211 void ieee80211_sched_scan_stopped_work(struct work_struct *work)
1212 {
1213         struct ieee80211_local *local =
1214                 container_of(work, struct ieee80211_local,
1215                              sched_scan_stopped_work);
1216
1217         ieee80211_sched_scan_end(local);
1218 }
1219
1220 void ieee80211_sched_scan_stopped(struct ieee80211_hw *hw)
1221 {
1222         struct ieee80211_local *local = hw_to_local(hw);
1223
1224         trace_api_sched_scan_stopped(local);
1225
1226         schedule_work(&local->sched_scan_stopped_work);
1227 }
1228 EXPORT_SYMBOL(ieee80211_sched_scan_stopped);