net/mac80211/scan.c

   1 /*
   2  * Scanning implementation
   3  *
   4  * Copyright 2003, Jouni Malinen <jkmaline@cc.hut.fi>
   5  * Copyright 2004, Instant802 Networks, Inc.
   6  * Copyright 2005, Devicescape Software, Inc.
   7  * Copyright 2006-2007  Jiri Benc <jbenc@suse.cz>
   8  * Copyright 2007, Michael Wu <flamingice@sourmilk.net>
   9  * Copyright 2013-2015  Intel Mobile Communications GmbH
  10  *
  11  * This program is free software; you can redistribute it and/or modify
  12  * it under the terms of the GNU General Public License version 2 as
  13  * published by the Free Software Foundation.
  14  */
  15
  16 #include <linux/if_arp.h>
  17 #include <linux/etherdevice.h>
  18 #include <linux/rtnetlink.h>
  19 #include <net/sch_generic.h>
  20 #include <linux/slab.h>
  21 #include <linux/export.h>
  22 #include <net/mac80211.h>
  23
  24 #include "ieee80211_i.h"
  25 #include "driver-ops.h"
  26 #include "mesh.h"
  27
  28 #define IEEE80211_PROBE_DELAY (HZ / 33)
  29 #define IEEE80211_CHANNEL_TIME (HZ / 33)
  30 #define IEEE80211_PASSIVE_CHANNEL_TIME (HZ / 9)
  31
  32 void ieee80211_rx_bss_put(struct ieee80211_local *local,
  33                           struct ieee80211_bss *bss)
  34 {
  35         if (!bss)
  36                 return;
  37         cfg80211_put_bss(local->hw.wiphy,
  38                          container_of((void *)bss, struct cfg80211_bss, priv));
  39 }
  40
  41 static bool is_uapsd_supported(struct ieee802_11_elems *elems)
  42 {
  43         u8 qos_info;
  44
  45         if (elems->wmm_info && elems->wmm_info_len == 7
  46             && elems->wmm_info[5] == 1)
  47                 qos_info = elems->wmm_info[6];
  48         else if (elems->wmm_param && elems->wmm_param_len == 24
  49                  && elems->wmm_param[5] == 1)
  50                 qos_info = elems->wmm_param[6];
  51         else
  52                 /* no valid wmm information or parameter element found */
  53                 return false;
  54
  55         return qos_info & IEEE80211_WMM_IE_AP_QOSINFO_UAPSD;
  56 }
  57
  58 struct ieee80211_bss *
  59 ieee80211_bss_info_update(struct ieee80211_local *local,
  60                           struct ieee80211_rx_status *rx_status,
  61                           struct ieee80211_mgmt *mgmt, size_t len,
  62                           struct ieee802_11_elems *elems,
  63                           struct ieee80211_channel *channel)
  64 {
  65         bool beacon = ieee80211_is_beacon(mgmt->frame_control);
  66         struct cfg80211_bss *cbss;
  67         struct ieee80211_bss *bss;
  68         int clen, srlen;
  69         struct cfg80211_inform_bss bss_meta = {
  70                 .boottime_ns = rx_status->boottime_ns,
  71         };
  72         bool signal_valid;
  73
  74         if (ieee80211_hw_check(&local->hw, SIGNAL_DBM))
  75                 bss_meta.signal = rx_status->signal * 100;
  76         else if (ieee80211_hw_check(&local->hw, SIGNAL_UNSPEC))
  77                 bss_meta.signal = (rx_status->signal * 100) / local->hw.max_signal;
  78
  79         bss_meta.scan_width = NL80211_BSS_CHAN_WIDTH_20;
  80         if (rx_status->flag & RX_FLAG_5MHZ)
  81                 bss_meta.scan_width = NL80211_BSS_CHAN_WIDTH_5;
  82         if (rx_status->flag & RX_FLAG_10MHZ)
  83                 bss_meta.scan_width = NL80211_BSS_CHAN_WIDTH_10;
  84
  85         bss_meta.chan = channel;
  86         cbss = cfg80211_inform_bss_frame_data(local->hw.wiphy, &bss_meta,
  87                                               mgmt, len, GFP_ATOMIC);
  88         if (!cbss)
  89                 return NULL;
  90         /* In case the signal is invalid update the status */
  91         signal_valid = abs(channel->center_freq - cbss->channel->center_freq)
  92                 <= local->hw.wiphy->max_adj_channel_rssi_comp;
  93         if (!signal_valid)
  94                 rx_status->flag |= RX_FLAG_NO_SIGNAL_VAL;
  95
  96         bss = (void *)cbss->priv;
  97
  98         if (beacon)
  99                 bss->device_ts_beacon = rx_status->device_timestamp;
 100         else
 101                 bss->device_ts_presp = rx_status->device_timestamp;
 102
 103         if (elems->parse_error) {
 104                 if (beacon)
 105                         bss->corrupt_data |= IEEE80211_BSS_CORRUPT_BEACON;
 106                 else
 107                         bss->corrupt_data |= IEEE80211_BSS_CORRUPT_PROBE_RESP;
 108         } else {
 109                 if (beacon)
 110                         bss->corrupt_data &= ~IEEE80211_BSS_CORRUPT_BEACON;
 111                 else
 112                         bss->corrupt_data &= ~IEEE80211_BSS_CORRUPT_PROBE_RESP;
 113         }
 114
 115         /* save the ERP value so that it is available at association time */
 116         if (elems->erp_info && (!elems->parse_error ||
 117                                 !(bss->valid_data & IEEE80211_BSS_VALID_ERP))) {
 118                 bss->erp_value = elems->erp_info[0];
 119                 bss->has_erp_value = true;
 120                 if (!elems->parse_error)
 121                         bss->valid_data |= IEEE80211_BSS_VALID_ERP;
 122         }
 123
 124         /* replace old supported rates if we get new values */
 125         if (!elems->parse_error ||
 126             !(bss->valid_data & IEEE80211_BSS_VALID_RATES)) {
 127                 srlen = 0;
 128                 if (elems->supp_rates) {
 129                         clen = IEEE80211_MAX_SUPP_RATES;
 130                         if (clen > elems->supp_rates_len)
 131                                 clen = elems->supp_rates_len;
 132                         memcpy(bss->supp_rates, elems->supp_rates, clen);
 133                         srlen += clen;
 134                 }
 135                 if (elems->ext_supp_rates) {
 136                         clen = IEEE80211_MAX_SUPP_RATES - srlen;
 137                         if (clen > elems->ext_supp_rates_len)
 138                                 clen = elems->ext_supp_rates_len;
 139                         memcpy(bss->supp_rates + srlen, elems->ext_supp_rates,
 140                                clen);
 141                         srlen += clen;
 142                 }
 143                 if (srlen) {
 144                         bss->supp_rates_len = srlen;
 145                         if (!elems->parse_error)
 146                                 bss->valid_data |= IEEE80211_BSS_VALID_RATES;
 147                 }
 148         }
 149
 150         if (!elems->parse_error ||
 151             !(bss->valid_data & IEEE80211_BSS_VALID_WMM)) {
 152                 bss->wmm_used = elems->wmm_param || elems->wmm_info;
 153                 bss->uapsd_supported = is_uapsd_supported(elems);
 154                 if (!elems->parse_error)
 155                         bss->valid_data |= IEEE80211_BSS_VALID_WMM;
 156         }
 157
 158         if (beacon) {
 159                 struct ieee80211_supported_band *sband =
 160                         local->hw.wiphy->bands[rx_status->band];
 161                 if (!(rx_status->flag & RX_FLAG_HT) &&
 162                     !(rx_status->flag & RX_FLAG_VHT))
 163                         bss->beacon_rate =
 164                                 &sband->bitrates[rx_status->rate_idx];
 165         }
 166
 167         return bss;
 168 }
 169
 170 void ieee80211_scan_rx(struct ieee80211_local *local, struct sk_buff *skb)
 171 {
 172         struct ieee80211_rx_status *rx_status = IEEE80211_SKB_RXCB(skb);
 173         struct ieee80211_sub_if_data *sdata1, *sdata2;
 174         struct ieee80211_mgmt *mgmt = (void *)skb->data;
 175         struct ieee80211_bss *bss;
 176         u8 *elements;
 177         struct ieee80211_channel *channel;
 178         size_t baselen;
 179         struct ieee802_11_elems elems;
 180
 181         if (skb->len < 24 ||
 182             (!ieee80211_is_probe_resp(mgmt->frame_control) &&
 183              !ieee80211_is_beacon(mgmt->frame_control)))
 184                 return;
 185
 186         sdata1 = rcu_dereference(local->scan_sdata);
 187         sdata2 = rcu_dereference(local->sched_scan_sdata);
 188
 189         if (likely(!sdata1 && !sdata2))
 190                 return;
 191
 192         if (ieee80211_is_probe_resp(mgmt->frame_control)) {
 193                 struct cfg80211_scan_request *scan_req;
 194                 struct cfg80211_sched_scan_request *sched_scan_req;
 195
 196                 scan_req = rcu_dereference(local->scan_req);
 197                 sched_scan_req = rcu_dereference(local->sched_scan_req);
 198
 199                 /* ignore ProbeResp to foreign address unless scanning
 200                  * with randomised address
 201                  */
 202                 if (!(sdata1 &&
 203                       (ether_addr_equal(mgmt->da, sdata1->vif.addr) ||
 204                        scan_req->flags & NL80211_SCAN_FLAG_RANDOM_ADDR)) &&
 205                     !(sdata2 &&
 206                       (ether_addr_equal(mgmt->da, sdata2->vif.addr) ||
 207                        sched_scan_req->flags & NL80211_SCAN_FLAG_RANDOM_ADDR)))
 208                         return;
 209
 210                 elements = mgmt->u.probe_resp.variable;
 211                 baselen = offsetof(struct ieee80211_mgmt, u.probe_resp.variable);
 212         } else {
 213                 baselen = offsetof(struct ieee80211_mgmt, u.beacon.variable);
 214                 elements = mgmt->u.beacon.variable;
 215         }
 216
 217         if (baselen > skb->len)
 218                 return;
 219
 220         ieee802_11_parse_elems(elements, skb->len - baselen, false, &elems);
 221
 222         channel = ieee80211_get_channel(local->hw.wiphy, rx_status->freq);
 223
 224         if (!channel || channel->flags & IEEE80211_CHAN_DISABLED)
 225                 return;
 226
 227         bss = ieee80211_bss_info_update(local, rx_status,
 228                                         mgmt, skb->len, &elems,
 229                                         channel);
 230         if (bss)
 231                 ieee80211_rx_bss_put(local, bss);
 232 }
 233
 234 static void
 235 ieee80211_prepare_scan_chandef(struct cfg80211_chan_def *chandef,
 236                                enum nl80211_bss_scan_width scan_width)
 237 {
 238         memset(chandef, 0, sizeof(*chandef));
 239         switch (scan_width) {
 240         case NL80211_BSS_CHAN_WIDTH_5:
 241                 chandef->width = NL80211_CHAN_WIDTH_5;
 242                 break;
 243         case NL80211_BSS_CHAN_WIDTH_10:
 244                 chandef->width = NL80211_CHAN_WIDTH_10;
 245                 break;
 246         default:
 247                 chandef->width = NL80211_CHAN_WIDTH_20_NOHT;
 248                 break;
 249         }
 250 }
 251
 252 /* return false if no more work */
 253 static bool ieee80211_prep_hw_scan(struct ieee80211_local *local)
 254 {
 255         struct cfg80211_scan_request *req;
 256         struct cfg80211_chan_def chandef;
 257         u8 bands_used = 0;
 258         int i, ielen, n_chans;
 259
 260         req = rcu_dereference_protected(local->scan_req,
 261                                         lockdep_is_held(&local->mtx));
 262
 263         if (test_bit(SCAN_HW_CANCELLED, &local->scanning))
 264                 return false;
 265
 266         if (ieee80211_hw_check(&local->hw, SINGLE_SCAN_ON_ALL_BANDS)) {
 267                 for (i = 0; i < req->n_channels; i++) {
 268                         local->hw_scan_req->req.channels[i] = req->channels[i];
 269                         bands_used |= BIT(req->channels[i]->band);
 270                 }
 271
 272                 n_chans = req->n_channels;
 273         } else {
 274                 do {
 275                         if (local->hw_scan_band == IEEE80211_NUM_BANDS)
 276                                 return false;
 277
 278                         n_chans = 0;
 279
 280                         for (i = 0; i < req->n_channels; i++) {
 281                                 if (req->channels[i]->band !=
 282                                     local->hw_scan_band)
 283                                         continue;
 284                                 local->hw_scan_req->req.channels[n_chans] =
 285                                                         req->channels[i];
 286                                 n_chans++;
 287                                 bands_used |= BIT(req->channels[i]->band);
 288                         }
 289
 290                         local->hw_scan_band++;
 291                 } while (!n_chans);
 292         }
 293
 294         local->hw_scan_req->req.n_channels = n_chans;
 295         ieee80211_prepare_scan_chandef(&chandef, req->scan_width);
 296
 297         ielen = ieee80211_build_preq_ies(local,
 298                                          (u8 *)local->hw_scan_req->req.ie,
 299                                          local->hw_scan_ies_bufsize,
 300                                          &local->hw_scan_req->ies,
 301                                          req->ie, req->ie_len,
 302                                          bands_used, req->rates, &chandef);
 303         local->hw_scan_req->req.ie_len = ielen;
 304         local->hw_scan_req->req.no_cck = req->no_cck;
 305         ether_addr_copy(local->hw_scan_req->req.mac_addr, req->mac_addr);
 306         ether_addr_copy(local->hw_scan_req->req.mac_addr_mask,
 307                         req->mac_addr_mask);
 308
 309         return true;
 310 }
 311
 312 static void __ieee80211_scan_completed(struct ieee80211_hw *hw, bool aborted)
 313 {
 314         struct ieee80211_local *local = hw_to_local(hw);
 315         bool hw_scan = local->ops->hw_scan;
 316         bool was_scanning = local->scanning;
 317         struct cfg80211_scan_request *scan_req;
 318         struct ieee80211_sub_if_data *scan_sdata;
 319         struct ieee80211_sub_if_data *sdata;
 320
 321         lockdep_assert_held(&local->mtx);
 322
 323         /*
 324          * It's ok to abort a not-yet-running scan (that
 325          * we have one at all will be verified by checking
 326          * local->scan_req next), but not to complete it
 327          * successfully.
 328          */
 329         if (WARN_ON(!local->scanning && !aborted))
 330                 aborted = true;
 331
 332         if (WARN_ON(!local->scan_req))
 333                 return;
 334
 335         if (hw_scan && !aborted &&
 336             !ieee80211_hw_check(&local->hw, SINGLE_SCAN_ON_ALL_BANDS) &&
 337             ieee80211_prep_hw_scan(local)) {
 338                 int rc;
 339
 340                 rc = drv_hw_scan(local,
 341                         rcu_dereference_protected(local->scan_sdata,
 342                                                   lockdep_is_held(&local->mtx)),
 343                         local->hw_scan_req);
 344
 345                 if (rc == 0)
 346                         return;
 347         }
 348
 349         kfree(local->hw_scan_req);
 350         local->hw_scan_req = NULL;
 351
 352         scan_req = rcu_dereference_protected(local->scan_req,
 353                                              lockdep_is_held(&local->mtx));
 354
 355         if (scan_req != local->int_scan_req)
 356                 cfg80211_scan_done(scan_req, aborted);
 357         RCU_INIT_POINTER(local->scan_req, NULL);
 358
 359         scan_sdata = rcu_dereference_protected(local->scan_sdata,
 360                                                lockdep_is_held(&local->mtx));
 361         RCU_INIT_POINTER(local->scan_sdata, NULL);
 362
 363         local->scanning = 0;
 364         local->scan_chandef.chan = NULL;
 365
 366         /* Set power back to normal operating levels. */
 367         ieee80211_hw_config(local, 0);
 368
 369         if (!hw_scan) {
 370                 ieee80211_configure_filter(local);
 371                 drv_sw_scan_complete(local, scan_sdata);
 372                 ieee80211_offchannel_return(local);
 373         }
 374
 375         ieee80211_recalc_idle(local);
 376
 377         ieee80211_mlme_notify_scan_completed(local);
 378         ieee80211_ibss_notify_scan_completed(local);
 379
 380         /* Requeue all the work that might have been ignored while
 381          * the scan was in progress; if there was none this will
 382          * just be a no-op for the particular interface.
 383          */
 384         list_for_each_entry_rcu(sdata, &local->interfaces, list) {
 385                 if (ieee80211_sdata_running(sdata))
 386                         ieee80211_queue_work(&sdata->local->hw, &sdata->work);
 387         }
 388
 389         if (was_scanning)
 390                 ieee80211_start_next_roc(local);
 391 }
 392
 393 void ieee80211_scan_completed(struct ieee80211_hw *hw, bool aborted)
 394 {
 395         struct ieee80211_local *local = hw_to_local(hw);
 396
 397         trace_api_scan_completed(local, aborted);
 398
 399         set_bit(SCAN_COMPLETED, &local->scanning);
 400         if (aborted)
 401                 set_bit(SCAN_ABORTED, &local->scanning);
 402         ieee80211_queue_delayed_work(&local->hw, &local->scan_work, 0);
 403 }
 404 EXPORT_SYMBOL(ieee80211_scan_completed);
 405
 406 static int ieee80211_start_sw_scan(struct ieee80211_local *local,
 407                                    struct ieee80211_sub_if_data *sdata)
 408 {
 409         /* Software scan is not supported in multi-channel cases */
 410         if (local->use_chanctx)
 411                 return -EOPNOTSUPP;
 412
 413         /*
 414          * Hardware/driver doesn't support hw_scan, so use software
 415          * scanning instead. First send a nullfunc frame with power save
 416          * bit on so that AP will buffer the frames for us while we are not
 417          * listening, then send probe requests to each channel and wait for
 418          * the responses. After all channels are scanned, tune back to the
 419          * original channel and send a nullfunc frame with power save bit
 420          * off to trigger the AP to send us all the buffered frames.
 421          *
 422          * Note that while local->sw_scanning is true everything else but
 423          * nullfunc frames and probe requests will be dropped in
 424          * ieee80211_tx_h_check_assoc().
 425          */
 426         drv_sw_scan_start(local, sdata, local->scan_addr);
 427
 428         local->leave_oper_channel_time = jiffies;
 429         local->next_scan_state = SCAN_DECISION;
 430         local->scan_channel_idx = 0;
 431
 432         ieee80211_offchannel_stop_vifs(local);
 433
 434         /* ensure nullfunc is transmitted before leaving operating channel */
 435         ieee80211_flush_queues(local, NULL, false);
 436
 437         ieee80211_configure_filter(local);
 438
 439         /* We need to set power level at maximum rate for scanning. */
 440         ieee80211_hw_config(local, 0);
 441
 442         ieee80211_queue_delayed_work(&local->hw,
 443                                      &local->scan_work, 0);
 444
 445         return 0;
 446 }
 447
 448 static bool ieee80211_can_scan(struct ieee80211_local *local,
 449                                struct ieee80211_sub_if_data *sdata)
 450 {
 451         if (ieee80211_is_radar_required(local))
 452                 return false;
 453
 454         if (!list_empty(&local->roc_list))
 455                 return false;
 456
 457         if (sdata->vif.type == NL80211_IFTYPE_STATION &&
 458             sdata->u.mgd.flags & IEEE80211_STA_CONNECTION_POLL)
 459                 return false;
 460
 461         return true;
 462 }
 463
 464 void ieee80211_run_deferred_scan(struct ieee80211_local *local)
 465 {
 466         lockdep_assert_held(&local->mtx);
 467
 468         if (!local->scan_req || local->scanning)
 469                 return;
 470
 471         if (!ieee80211_can_scan(local,
 472                                 rcu_dereference_protected(
 473                                         local->scan_sdata,
 474                                         lockdep_is_held(&local->mtx))))
 475                 return;
 476
 477         ieee80211_queue_delayed_work(&local->hw, &local->scan_work,
 478                                      round_jiffies_relative(0));
 479 }
 480
 481 static void ieee80211_scan_state_send_probe(struct ieee80211_local *local,
 482                                             unsigned long *next_delay)
 483 {
 484         int i;
 485         struct ieee80211_sub_if_data *sdata;
 486         struct cfg80211_scan_request *scan_req;
 487         enum ieee80211_band band = local->hw.conf.chandef.chan->band;
 488         u32 tx_flags;
 489
 490         scan_req = rcu_dereference_protected(local->scan_req,
 491                                              lockdep_is_held(&local->mtx));
 492
 493         tx_flags = IEEE80211_TX_INTFL_OFFCHAN_TX_OK;
 494         if (scan_req->no_cck)
 495                 tx_flags |= IEEE80211_TX_CTL_NO_CCK_RATE;
 496
 497         sdata = rcu_dereference_protected(local->scan_sdata,
 498                                           lockdep_is_held(&local->mtx));
 499
 500         for (i = 0; i < scan_req->n_ssids; i++)
 501                 ieee80211_send_probe_req(
 502                         sdata, local->scan_addr, NULL,
 503                         scan_req->ssids[i].ssid, scan_req->ssids[i].ssid_len,
 504                         scan_req->ie, scan_req->ie_len,
 505                         scan_req->rates[band], false,
 506                         tx_flags, local->hw.conf.chandef.chan, true);
 507
 508         /*
 509          * After sending probe requests, wait for probe responses
 510          * on the channel.
 511          */
 512         *next_delay = IEEE80211_CHANNEL_TIME;
 513         local->next_scan_state = SCAN_DECISION;
 514 }
 515
 516 static int __ieee80211_start_scan(struct ieee80211_sub_if_data *sdata,
 517                                   struct cfg80211_scan_request *req)
 518 {
 519         struct ieee80211_local *local = sdata->local;
 520         int rc;
 521
 522         lockdep_assert_held(&local->mtx);
 523
 524         if (local->scan_req || ieee80211_is_radar_required(local))
 525                 return -EBUSY;
 526
 527         if (!ieee80211_can_scan(local, sdata)) {
 528                 /* wait for the work to finish/time out */
 529                 rcu_assign_pointer(local->scan_req, req);
 530                 rcu_assign_pointer(local->scan_sdata, sdata);
 531                 return 0;
 532         }
 533
 534         if (local->ops->hw_scan) {
 535                 u8 *ies;
 536
 537                 local->hw_scan_ies_bufsize = local->scan_ies_len + req->ie_len;
 538
 539                 if (ieee80211_hw_check(&local->hw, SINGLE_SCAN_ON_ALL_BANDS)) {
 540                         int i, n_bands = 0;
 541                         u8 bands_counted = 0;
 542
 543                         for (i = 0; i < req->n_channels; i++) {
 544                                 if (bands_counted & BIT(req->channels[i]->band))
 545                                         continue;
 546                                 bands_counted |= BIT(req->channels[i]->band);
 547                                 n_bands++;
 548                         }
 549
 550                         local->hw_scan_ies_bufsize *= n_bands;
 551                 }
 552
 553                 local->hw_scan_req = kmalloc(
 554                                 sizeof(*local->hw_scan_req) +
 555                                 req->n_channels * sizeof(req->channels[0]) +
 556                                 local->hw_scan_ies_bufsize, GFP_KERNEL);
 557                 if (!local->hw_scan_req)
 558                         return -ENOMEM;
 559
 560                 local->hw_scan_req->req.ssids = req->ssids;
 561                 local->hw_scan_req->req.n_ssids = req->n_ssids;
 562                 ies = (u8 *)local->hw_scan_req +
 563                         sizeof(*local->hw_scan_req) +
 564                         req->n_channels * sizeof(req->channels[0]);
 565                 local->hw_scan_req->req.ie = ies;
 566                 local->hw_scan_req->req.flags = req->flags;
 567
 568                 local->hw_scan_band = 0;
 569
 570                 /*
 571                  * After allocating local->hw_scan_req, we must
 572                  * go through until ieee80211_prep_hw_scan(), so
 573                  * anything that might be changed here and leave
 574                  * this function early must not go after this
 575                  * allocation.
 576                  */
 577         }
 578
 579         rcu_assign_pointer(local->scan_req, req);
 580         rcu_assign_pointer(local->scan_sdata, sdata);
 581
 582         if (req->flags & NL80211_SCAN_FLAG_RANDOM_ADDR)
 583                 get_random_mask_addr(local->scan_addr,
 584                                      req->mac_addr,
 585                                      req->mac_addr_mask);
 586         else
 587                 memcpy(local->scan_addr, sdata->vif.addr, ETH_ALEN);
 588
 589         if (local->ops->hw_scan) {
 590                 __set_bit(SCAN_HW_SCANNING, &local->scanning);
 591         } else if ((req->n_channels == 1) &&
 592                    (req->channels[0] == local->_oper_chandef.chan)) {
 593                 /*
 594                  * If we are scanning only on the operating channel
 595                  * then we do not need to stop normal activities
 596                  */
 597                 unsigned long next_delay;
 598
 599                 __set_bit(SCAN_ONCHANNEL_SCANNING, &local->scanning);
 600
 601                 ieee80211_recalc_idle(local);
 602
 603                 /* Notify driver scan is starting, keep order of operations
 604                  * same as normal software scan, in case that matters. */
 605                 drv_sw_scan_start(local, sdata, local->scan_addr);
 606
 607                 ieee80211_configure_filter(local); /* accept probe-responses */
 608
 609                 /* We need to ensure power level is at max for scanning. */
 610                 ieee80211_hw_config(local, 0);
 611
 612                 if ((req->channels[0]->flags & (IEEE80211_CHAN_NO_IR |
 613                                                 IEEE80211_CHAN_RADAR)) ||
 614                     !req->n_ssids) {
 615                         next_delay = IEEE80211_PASSIVE_CHANNEL_TIME;
 616                 } else {
 617                         ieee80211_scan_state_send_probe(local, &next_delay);
 618                         next_delay = IEEE80211_CHANNEL_TIME;
 619                 }
 620
 621                 /* Now, just wait a bit and we are all done! */
 622                 ieee80211_queue_delayed_work(&local->hw, &local->scan_work,
 623                                              next_delay);
 624                 return 0;
 625         } else {
 626                 /* Do normal software scan */
 627                 __set_bit(SCAN_SW_SCANNING, &local->scanning);
 628         }
 629
 630         ieee80211_recalc_idle(local);
 631
 632         if (local->ops->hw_scan) {
 633                 WARN_ON(!ieee80211_prep_hw_scan(local));
 634                 rc = drv_hw_scan(local, sdata, local->hw_scan_req);
 635         } else {
 636                 rc = ieee80211_start_sw_scan(local, sdata);
 637         }
 638
 639         if (rc) {
 640                 kfree(local->hw_scan_req);
 641                 local->hw_scan_req = NULL;
 642                 local->scanning = 0;
 643
 644                 ieee80211_recalc_idle(local);
 645
 646                 local->scan_req = NULL;
 647                 RCU_INIT_POINTER(local->scan_sdata, NULL);
 648         }
 649
 650         return rc;
 651 }
 652
 653 static unsigned long
 654 ieee80211_scan_get_channel_time(struct ieee80211_channel *chan)
 655 {
 656         /*
 657          * TODO: channel switching also consumes quite some time,
 658          * add that delay as well to get a better estimation
 659          */
 660         if (chan->flags & (IEEE80211_CHAN_NO_IR | IEEE80211_CHAN_RADAR))
 661                 return IEEE80211_PASSIVE_CHANNEL_TIME;
 662         return IEEE80211_PROBE_DELAY + IEEE80211_CHANNEL_TIME;
 663 }
 664
 665 static void ieee80211_scan_state_decision(struct ieee80211_local *local,
 666                                           unsigned long *next_delay)
 667 {
 668         bool associated = false;
 669         bool tx_empty = true;
 670         bool bad_latency;
 671         struct ieee80211_sub_if_data *sdata;
 672         struct ieee80211_channel *next_chan;
 673         enum mac80211_scan_state next_scan_state;
 674         struct cfg80211_scan_request *scan_req;
 675
 676         /*
 677          * check if at least one STA interface is associated,
 678          * check if at least one STA interface has pending tx frames
 679          * and grab the lowest used beacon interval
 680          */
 681         mutex_lock(&local->iflist_mtx);
 682         list_for_each_entry(sdata, &local->interfaces, list) {
 683                 if (!ieee80211_sdata_running(sdata))
 684                         continue;
 685
 686                 if (sdata->vif.type == NL80211_IFTYPE_STATION) {
 687                         if (sdata->u.mgd.associated) {
 688                                 associated = true;
 689
 690                                 if (!qdisc_all_tx_empty(sdata->dev)) {
 691                                         tx_empty = false;
 692                                         break;
 693                                 }
 694                         }
 695                 }
 696         }
 697         mutex_unlock(&local->iflist_mtx);
 698
 699         scan_req = rcu_dereference_protected(local->scan_req,
 700                                              lockdep_is_held(&local->mtx));
 701
 702         next_chan = scan_req->channels[local->scan_channel_idx];
 703
 704         /*
 705          * we're currently scanning a different channel, let's
 706          * see if we can scan another channel without interfering
 707          * with the current traffic situation.
 708          *
 709          * Keep good latency, do not stay off-channel more than 125 ms.
 710          */
 711
 712         bad_latency = time_after(jiffies +
 713                                  ieee80211_scan_get_channel_time(next_chan),
 714                                  local->leave_oper_channel_time + HZ / 8);
 715
 716         if (associated && !tx_empty) {
 717                 if (scan_req->flags & NL80211_SCAN_FLAG_LOW_PRIORITY)
 718                         next_scan_state = SCAN_ABORT;
 719                 else
 720                         next_scan_state = SCAN_SUSPEND;
 721         } else if (associated && bad_latency) {
 722                 next_scan_state = SCAN_SUSPEND;
 723         } else {
 724                 next_scan_state = SCAN_SET_CHANNEL;
 725         }
 726
 727         local->next_scan_state = next_scan_state;
 728
 729         *next_delay = 0;
 730 }
 731
 732 static void ieee80211_scan_state_set_channel(struct ieee80211_local *local,
 733                                              unsigned long *next_delay)
 734 {
 735         int skip;
 736         struct ieee80211_channel *chan;
 737         enum nl80211_bss_scan_width oper_scan_width;
 738         struct cfg80211_scan_request *scan_req;
 739
 740         scan_req = rcu_dereference_protected(local->scan_req,
 741                                              lockdep_is_held(&local->mtx));
 742
 743         skip = 0;
 744         chan = scan_req->channels[local->scan_channel_idx];
 745
 746         local->scan_chandef.chan = chan;
 747         local->scan_chandef.center_freq1 = chan->center_freq;
 748         local->scan_chandef.center_freq2 = 0;
 749         switch (scan_req->scan_width) {
 750         case NL80211_BSS_CHAN_WIDTH_5:
 751                 local->scan_chandef.width = NL80211_CHAN_WIDTH_5;
 752                 break;
 753         case NL80211_BSS_CHAN_WIDTH_10:
 754                 local->scan_chandef.width = NL80211_CHAN_WIDTH_10;
 755                 break;
 756         case NL80211_BSS_CHAN_WIDTH_20:
 757                 /* If scanning on oper channel, use whatever channel-type
 758                  * is currently in use.
 759                  */
 760                 oper_scan_width = cfg80211_chandef_to_scan_width(
 761                                         &local->_oper_chandef);
 762                 if (chan == local->_oper_chandef.chan &&
 763                     oper_scan_width == scan_req->scan_width)
 764                         local->scan_chandef = local->_oper_chandef;
 765                 else
 766                         local->scan_chandef.width = NL80211_CHAN_WIDTH_20_NOHT;
 767                 break;
 768         }
 769
 770         if (ieee80211_hw_config(local, IEEE80211_CONF_CHANGE_CHANNEL))
 771                 skip = 1;
 772
 773         /* advance state machine to next channel/band */
 774         local->scan_channel_idx++;
 775
 776         if (skip) {
 777                 /* if we skip this channel return to the decision state */
 778                 local->next_scan_state = SCAN_DECISION;
 779                 return;
 780         }
 781
 782         /*
 783          * Probe delay is used to update the NAV, cf. 11.1.3.2.2
 784          * (which unfortunately doesn't say _why_ step a) is done,
 785          * but it waits for the probe delay or until a frame is
 786          * received - and the received frame would update the NAV).
 787          * For now, we do not support waiting until a frame is
 788          * received.
 789          *
 790          * In any case, it is not necessary for a passive scan.
 791          */
 792         if ((chan->flags & (IEEE80211_CHAN_NO_IR | IEEE80211_CHAN_RADAR)) ||
 793             !scan_req->n_ssids) {
 794                 *next_delay = IEEE80211_PASSIVE_CHANNEL_TIME;
 795                 local->next_scan_state = SCAN_DECISION;
 796                 return;
 797         }
 798
 799         /* active scan, send probes */
 800         *next_delay = IEEE80211_PROBE_DELAY;
 801         local->next_scan_state = SCAN_SEND_PROBE;
 802 }
 803
 804 static void ieee80211_scan_state_suspend(struct ieee80211_local *local,
 805                                          unsigned long *next_delay)
 806 {
 807         /* switch back to the operating channel */
 808         local->scan_chandef.chan = NULL;
 809         ieee80211_hw_config(local, IEEE80211_CONF_CHANGE_CHANNEL);
 810
 811         /* disable PS */
 812         ieee80211_offchannel_return(local);
 813
 814         *next_delay = HZ / 5;
 815         /* afterwards, resume scan & go to next channel */
 816         local->next_scan_state = SCAN_RESUME;
 817 }
 818
 819 static void ieee80211_scan_state_resume(struct ieee80211_local *local,
 820                                         unsigned long *next_delay)
 821 {
 822         ieee80211_offchannel_stop_vifs(local);
 823
 824         if (local->ops->flush) {
 825                 ieee80211_flush_queues(local, NULL, false);
 826                 *next_delay = 0;
 827         } else
 828                 *next_delay = HZ / 10;
 829
 830         /* remember when we left the operating channel */
 831         local->leave_oper_channel_time = jiffies;
 832
 833         /* advance to the next channel to be scanned */
 834         local->next_scan_state = SCAN_SET_CHANNEL;
 835 }
 836
 837 void ieee80211_scan_work(struct work_struct *work)
 838 {
 839         struct ieee80211_local *local =
 840                 container_of(work, struct ieee80211_local, scan_work.work);
 841         struct ieee80211_sub_if_data *sdata;
 842         struct cfg80211_scan_request *scan_req;
 843         unsigned long next_delay = 0;
 844         bool aborted;
 845
 846         mutex_lock(&local->mtx);
 847
 848         if (!ieee80211_can_run_worker(local)) {
 849                 aborted = true;
 850                 goto out_complete;
 851         }
 852
 853         sdata = rcu_dereference_protected(local->scan_sdata,
 854                                           lockdep_is_held(&local->mtx));
 855         scan_req = rcu_dereference_protected(local->scan_req,
 856                                              lockdep_is_held(&local->mtx));
 857
 858         /* When scanning on-channel, the first-callback means completed. */
 859         if (test_bit(SCAN_ONCHANNEL_SCANNING, &local->scanning)) {
 860                 aborted = test_and_clear_bit(SCAN_ABORTED, &local->scanning);
 861                 goto out_complete;
 862         }
 863
 864         if (test_and_clear_bit(SCAN_COMPLETED, &local->scanning)) {
 865                 aborted = test_and_clear_bit(SCAN_ABORTED, &local->scanning);
 866                 goto out_complete;
 867         }
 868
 869         if (!sdata || !scan_req)
 870                 goto out;
 871
 872         if (!local->scanning) {
 873                 int rc;
 874
 875                 RCU_INIT_POINTER(local->scan_req, NULL);
 876                 RCU_INIT_POINTER(local->scan_sdata, NULL);
 877
 878                 rc = __ieee80211_start_scan(sdata, scan_req);
 879                 if (rc) {
 880                         /* need to complete scan in cfg80211 */
 881                         rcu_assign_pointer(local->scan_req, scan_req);
 882                         aborted = true;
 883                         goto out_complete;
 884                 } else
 885                         goto out;
 886         }
 887
 888         /*
 889          * as long as no delay is required advance immediately
 890          * without scheduling a new work
 891          */
 892         do {
 893                 if (!ieee80211_sdata_running(sdata)) {
 894                         aborted = true;
 895                         goto out_complete;
 896                 }
 897
 898                 switch (local->next_scan_state) {
 899                 case SCAN_DECISION:
 900                         /* if no more bands/channels left, complete scan */
 901                         if (local->scan_channel_idx >= scan_req->n_channels) {
 902                                 aborted = false;
 903                                 goto out_complete;
 904                         }
 905                         ieee80211_scan_state_decision(local, &next_delay);
 906                         break;
 907                 case SCAN_SET_CHANNEL:
 908                         ieee80211_scan_state_set_channel(local, &next_delay);
 909                         break;
 910                 case SCAN_SEND_PROBE:
 911                         ieee80211_scan_state_send_probe(local, &next_delay);
 912                         break;
 913                 case SCAN_SUSPEND:
 914                         ieee80211_scan_state_suspend(local, &next_delay);
 915                         break;
 916                 case SCAN_RESUME:
 917                         ieee80211_scan_state_resume(local, &next_delay);
 918                         break;
 919                 case SCAN_ABORT:
 920                         aborted = true;
 921                         goto out_complete;
 922                 }
 923         } while (next_delay == 0);
 924
 925         ieee80211_queue_delayed_work(&local->hw, &local->scan_work, next_delay);
 926         goto out;
 927
 928 out_complete:
 929         __ieee80211_scan_completed(&local->hw, aborted);
 930 out:
 931         mutex_unlock(&local->mtx);
 932 }
 933
 934 int ieee80211_request_scan(struct ieee80211_sub_if_data *sdata,
 935                            struct cfg80211_scan_request *req)
 936 {
 937         int res;
 938
 939         mutex_lock(&sdata->local->mtx);
 940         res = __ieee80211_start_scan(sdata, req);
 941         mutex_unlock(&sdata->local->mtx);
 942
 943         return res;
 944 }
 945
 946 int ieee80211_request_ibss_scan(struct ieee80211_sub_if_data *sdata,
 947                                 const u8 *ssid, u8 ssid_len,
 948                                 struct ieee80211_channel **channels,
 949                                 unsigned int n_channels,
 950                                 enum nl80211_bss_scan_width scan_width)
 951 {
 952         struct ieee80211_local *local = sdata->local;
 953         int ret = -EBUSY, i, n_ch = 0;
 954         enum ieee80211_band band;
 955
 956         mutex_lock(&local->mtx);
 957
 958         /* busy scanning */
 959         if (local->scan_req)
 960                 goto unlock;
 961
 962         /* fill internal scan request */
 963         if (!channels) {
 964                 int max_n;
 965
 966                 for (band = 0; band < IEEE80211_NUM_BANDS; band++) {
 967                         if (!local->hw.wiphy->bands[band])
 968                                 continue;
 969
 970                         max_n = local->hw.wiphy->bands[band]->n_channels;
 971                         for (i = 0; i < max_n; i++) {
 972                                 struct ieee80211_channel *tmp_ch =
 973                                     &local->hw.wiphy->bands[band]->channels[i];
 974
 975                                 if (tmp_ch->flags & (IEEE80211_CHAN_NO_IR |
 976                                                      IEEE80211_CHAN_DISABLED))
 977                                         continue;
 978
 979                                 local->int_scan_req->channels[n_ch] = tmp_ch;
 980                                 n_ch++;
 981                         }
 982                 }
 983
 984                 if (WARN_ON_ONCE(n_ch == 0))
 985                         goto unlock;
 986
 987                 local->int_scan_req->n_channels = n_ch;
 988         } else {
 989                 for (i = 0; i < n_channels; i++) {
 990                         if (channels[i]->flags & (IEEE80211_CHAN_NO_IR |
 991                                                   IEEE80211_CHAN_DISABLED))
 992                                 continue;
 993
 994                         local->int_scan_req->channels[n_ch] = channels[i];
 995                         n_ch++;
 996                 }
 997
 998                 if (WARN_ON_ONCE(n_ch == 0))
 999                         goto unlock;
1000
1001                 local->int_scan_req->n_channels = n_ch;
1002         }
1003
1004         local->int_scan_req->ssids = &local->scan_ssid;
1005         local->int_scan_req->n_ssids = 1;
1006         local->int_scan_req->scan_width = scan_width;
1007         memcpy(local->int_scan_req->ssids[0].ssid, ssid, IEEE80211_MAX_SSID_LEN);
1008         local->int_scan_req->ssids[0].ssid_len = ssid_len;
1009
1010         ret = __ieee80211_start_scan(sdata, sdata->local->int_scan_req);
1011  unlock:
1012         mutex_unlock(&local->mtx);
1013         return ret;
1014 }
1015
1016 /*
1017  * Only call this function when a scan can't be queued -- under RTNL.
1018  */
1019 void ieee80211_scan_cancel(struct ieee80211_local *local)
1020 {
1021         /*
1022          * We are canceling software scan, or deferred scan that was not
1023          * yet really started (see __ieee80211_start_scan ).
1024          *
1025          * Regarding hardware scan:
1026          * - we can not call  __ieee80211_scan_completed() as when
1027          *   SCAN_HW_SCANNING bit is set this function change
1028          *   local->hw_scan_req to operate on 5G band, what race with
1029          *   driver which can use local->hw_scan_req
1030          *
1031          * - we can not cancel scan_work since driver can schedule it
1032          *   by ieee80211_scan_completed(..., true) to finish scan
1033          *
1034          * Hence we only call the cancel_hw_scan() callback, but the low-level
1035          * driver is still responsible for calling ieee80211_scan_completed()
1036          * after the scan was completed/aborted.
1037          */
1038
1039         mutex_lock(&local->mtx);
1040         if (!local->scan_req)
1041                 goto out;
1042
1043         /*
1044          * We have a scan running and the driver already reported completion,
1045          * but the worker hasn't run yet or is stuck on the mutex - mark it as
1046          * cancelled.
1047          */
1048         if (test_bit(SCAN_HW_SCANNING, &local->scanning) &&
1049             test_bit(SCAN_COMPLETED, &local->scanning)) {
1050                 set_bit(SCAN_HW_CANCELLED, &local->scanning);
1051                 goto out;
1052         }
1053
1054         if (test_bit(SCAN_HW_SCANNING, &local->scanning)) {
1055                 /*
1056                  * Make sure that __ieee80211_scan_completed doesn't trigger a
1057                  * scan on another band.
1058                  */
1059                 set_bit(SCAN_HW_CANCELLED, &local->scanning);
1060                 if (local->ops->cancel_hw_scan)
1061                         drv_cancel_hw_scan(local,
1062                                 rcu_dereference_protected(local->scan_sdata,
1063                                                 lockdep_is_held(&local->mtx)));
1064                 goto out;
1065         }
1066
1067         /*
1068          * If the work is currently running, it must be blocked on
1069          * the mutex, but we'll set scan_sdata = NULL and it'll
1070          * simply exit once it acquires the mutex.
1071          */
1072         cancel_delayed_work(&local->scan_work);
1073         /* and clean up */
1074         __ieee80211_scan_completed(&local->hw, true);
1075 out:
1076         mutex_unlock(&local->mtx);
1077 }
1078
1079 int __ieee80211_request_sched_scan_start(struct ieee80211_sub_if_data *sdata,
1080                                         struct cfg80211_sched_scan_request *req)
1081 {
1082         struct ieee80211_local *local = sdata->local;
1083         struct ieee80211_scan_ies sched_scan_ies = {};
1084         struct cfg80211_chan_def chandef;
1085         int ret, i, iebufsz, num_bands = 0;
1086         u32 rate_masks[IEEE80211_NUM_BANDS] = {};
1087         u8 bands_used = 0;
1088         u8 *ie;
1089         size_t len;
1090
1091         iebufsz = local->scan_ies_len + req->ie_len;
1092
1093         lockdep_assert_held(&local->mtx);
1094
1095         if (!local->ops->sched_scan_start)
1096                 return -ENOTSUPP;
1097
1098         for (i = 0; i < IEEE80211_NUM_BANDS; i++) {
1099                 if (local->hw.wiphy->bands[i]) {
1100                         bands_used |= BIT(i);
1101                         rate_masks[i] = (u32) -1;
1102                         num_bands++;
1103                 }
1104         }
1105
1106         ie = kzalloc(num_bands * iebufsz, GFP_KERNEL);
1107         if (!ie) {
1108                 ret = -ENOMEM;
1109                 goto out;
1110         }
1111
1112         ieee80211_prepare_scan_chandef(&chandef, req->scan_width);
1113
1114         len = ieee80211_build_preq_ies(local, ie, num_bands * iebufsz,
1115                                        &sched_scan_ies, req->ie,
1116                                        req->ie_len, bands_used,
1117                                        rate_masks, &chandef);
1118
1119         ret = drv_sched_scan_start(local, sdata, req, &sched_scan_ies);
1120         if (ret == 0) {
1121                 rcu_assign_pointer(local->sched_scan_sdata, sdata);
1122                 rcu_assign_pointer(local->sched_scan_req, req);
1123         }
1124
1125         kfree(ie);
1126
1127 out:
1128         if (ret) {
1129                 /* Clean in case of failure after HW restart or upon resume. */
1130                 RCU_INIT_POINTER(local->sched_scan_sdata, NULL);
1131                 RCU_INIT_POINTER(local->sched_scan_req, NULL);
1132         }
1133
1134         return ret;
1135 }
1136
1137 int ieee80211_request_sched_scan_start(struct ieee80211_sub_if_data *sdata,
1138                                        struct cfg80211_sched_scan_request *req)
1139 {
1140         struct ieee80211_local *local = sdata->local;
1141         int ret;
1142
1143         mutex_lock(&local->mtx);
1144
1145         if (rcu_access_pointer(local->sched_scan_sdata)) {
1146                 mutex_unlock(&local->mtx);
1147                 return -EBUSY;
1148         }
1149
1150         ret = __ieee80211_request_sched_scan_start(sdata, req);
1151
1152         mutex_unlock(&local->mtx);
1153         return ret;
1154 }
1155
1156 int ieee80211_request_sched_scan_stop(struct ieee80211_local *local)
1157 {
1158         struct ieee80211_sub_if_data *sched_scan_sdata;
1159         int ret = -ENOENT;
1160
1161         mutex_lock(&local->mtx);
1162
1163         if (!local->ops->sched_scan_stop) {
1164                 ret = -ENOTSUPP;
1165                 goto out;
1166         }
1167
1168         /* We don't want to restart sched scan anymore. */
1169         RCU_INIT_POINTER(local->sched_scan_req, NULL);
1170
1171         sched_scan_sdata = rcu_dereference_protected(local->sched_scan_sdata,
1172                                                 lockdep_is_held(&local->mtx));
1173         if (sched_scan_sdata) {
1174                 ret = drv_sched_scan_stop(local, sched_scan_sdata);
1175                 if (!ret)
1176                         RCU_INIT_POINTER(local->sched_scan_sdata, NULL);
1177         }
1178 out:
1179         mutex_unlock(&local->mtx);
1180
1181         return ret;
1182 }
1183
1184 void ieee80211_sched_scan_results(struct ieee80211_hw *hw)
1185 {
1186         struct ieee80211_local *local = hw_to_local(hw);
1187
1188         trace_api_sched_scan_results(local);
1189
1190         cfg80211_sched_scan_results(hw->wiphy);
1191 }
1192 EXPORT_SYMBOL(ieee80211_sched_scan_results);
1193
1194 void ieee80211_sched_scan_end(struct ieee80211_local *local)
1195 {
1196         mutex_lock(&local->mtx);
1197
1198         if (!rcu_access_pointer(local->sched_scan_sdata)) {
1199                 mutex_unlock(&local->mtx);
1200                 return;
1201         }
1202
1203         RCU_INIT_POINTER(local->sched_scan_sdata, NULL);
1204
1205         /* If sched scan was aborted by the driver. */
1206         RCU_INIT_POINTER(local->sched_scan_req, NULL);
1207
1208         mutex_unlock(&local->mtx);
1209
1210         cfg80211_sched_scan_stopped(local->hw.wiphy);
1211 }
1212
1213 void ieee80211_sched_scan_stopped_work(struct work_struct *work)
1214 {
1215         struct ieee80211_local *local =
1216                 container_of(work, struct ieee80211_local,
1217                              sched_scan_stopped_work);
1218
1219         ieee80211_sched_scan_end(local);
1220 }
1221
1222 void ieee80211_sched_scan_stopped(struct ieee80211_hw *hw)
1223 {
1224         struct ieee80211_local *local = hw_to_local(hw);
1225
1226         trace_api_sched_scan_stopped(local);
1227
1228         /*
1229          * this shouldn't really happen, so for simplicity
1230          * simply ignore it, and let mac80211 reconfigure
1231          * the sched scan later on.
1232          */
1233         if (local->in_reconfig)
1234                 return;
1235
1236         schedule_work(&local->sched_scan_stopped_work);
1237 }
1238 EXPORT_SYMBOL(ieee80211_sched_scan_stopped);