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  *
  10  * This program is free software; you can redistribute it and/or modify
  11  * it under the terms of the GNU General Public License version 2 as
  12  * published by the Free Software Foundation.
  13  */
  14
  15 #include <linux/if_arp.h>
  16 #include <linux/etherdevice.h>
  17 #include <linux/rtnetlink.h>
  18 #include <linux/pm_qos.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         s32 signal = 0;
  70
  71         if (local->hw.flags & IEEE80211_HW_SIGNAL_DBM)
  72                 signal = rx_status->signal * 100;
  73         else if (local->hw.flags & IEEE80211_HW_SIGNAL_UNSPEC)
  74                 signal = (rx_status->signal * 100) / local->hw.max_signal;
  75
  76         cbss = cfg80211_inform_bss_frame(local->hw.wiphy, channel,
  77                                          mgmt, len, signal, GFP_ATOMIC);
  78         if (!cbss)
  79                 return NULL;
  80
  81         bss = (void *)cbss->priv;
  82
  83         if (beacon)
  84                 bss->device_ts_beacon = rx_status->device_timestamp;
  85         else
  86                 bss->device_ts_presp = rx_status->device_timestamp;
  87
  88         if (elems->parse_error) {
  89                 if (beacon)
  90                         bss->corrupt_data |= IEEE80211_BSS_CORRUPT_BEACON;
  91                 else
  92                         bss->corrupt_data |= IEEE80211_BSS_CORRUPT_PROBE_RESP;
  93         } else {
  94                 if (beacon)
  95                         bss->corrupt_data &= ~IEEE80211_BSS_CORRUPT_BEACON;
  96                 else
  97                         bss->corrupt_data &= ~IEEE80211_BSS_CORRUPT_PROBE_RESP;
  98         }
  99
 100         /* save the ERP value so that it is available at association time */
 101         if (elems->erp_info && elems->erp_info_len >= 1 &&
 102                         (!elems->parse_error ||
 103                          !(bss->valid_data & IEEE80211_BSS_VALID_ERP))) {
 104                 bss->erp_value = elems->erp_info[0];
 105                 bss->has_erp_value = true;
 106                 if (!elems->parse_error)
 107                         bss->valid_data |= IEEE80211_BSS_VALID_ERP;
 108         }
 109
 110         /* replace old supported rates if we get new values */
 111         if (!elems->parse_error ||
 112             !(bss->valid_data & IEEE80211_BSS_VALID_RATES)) {
 113                 srlen = 0;
 114                 if (elems->supp_rates) {
 115                         clen = IEEE80211_MAX_SUPP_RATES;
 116                         if (clen > elems->supp_rates_len)
 117                                 clen = elems->supp_rates_len;
 118                         memcpy(bss->supp_rates, elems->supp_rates, clen);
 119                         srlen += clen;
 120                 }
 121                 if (elems->ext_supp_rates) {
 122                         clen = IEEE80211_MAX_SUPP_RATES - srlen;
 123                         if (clen > elems->ext_supp_rates_len)
 124                                 clen = elems->ext_supp_rates_len;
 125                         memcpy(bss->supp_rates + srlen, elems->ext_supp_rates,
 126                                clen);
 127                         srlen += clen;
 128                 }
 129                 if (srlen) {
 130                         bss->supp_rates_len = srlen;
 131                         if (!elems->parse_error)
 132                                 bss->valid_data |= IEEE80211_BSS_VALID_RATES;
 133                 }
 134         }
 135
 136         if (!elems->parse_error ||
 137             !(bss->valid_data & IEEE80211_BSS_VALID_WMM)) {
 138                 bss->wmm_used = elems->wmm_param || elems->wmm_info;
 139                 bss->uapsd_supported = is_uapsd_supported(elems);
 140                 if (!elems->parse_error)
 141                         bss->valid_data |= IEEE80211_BSS_VALID_WMM;
 142         }
 143
 144         return bss;
 145 }
 146
 147 void ieee80211_scan_rx(struct ieee80211_local *local, struct sk_buff *skb)
 148 {
 149         struct ieee80211_rx_status *rx_status = IEEE80211_SKB_RXCB(skb);
 150         struct ieee80211_sub_if_data *sdata1, *sdata2;
 151         struct ieee80211_mgmt *mgmt = (void *)skb->data;
 152         struct ieee80211_bss *bss;
 153         u8 *elements;
 154         struct ieee80211_channel *channel;
 155         size_t baselen;
 156         bool beacon;
 157         struct ieee802_11_elems elems;
 158
 159         if (skb->len < 24 ||
 160             (!ieee80211_is_probe_resp(mgmt->frame_control) &&
 161              !ieee80211_is_beacon(mgmt->frame_control)))
 162                 return;
 163
 164         sdata1 = rcu_dereference(local->scan_sdata);
 165         sdata2 = rcu_dereference(local->sched_scan_sdata);
 166
 167         if (likely(!sdata1 && !sdata2))
 168                 return;
 169
 170         if (ieee80211_is_probe_resp(mgmt->frame_control)) {
 171                 /* ignore ProbeResp to foreign address */
 172                 if ((!sdata1 || !ether_addr_equal(mgmt->da, sdata1->vif.addr)) &&
 173                     (!sdata2 || !ether_addr_equal(mgmt->da, sdata2->vif.addr)))
 174                         return;
 175
 176                 elements = mgmt->u.probe_resp.variable;
 177                 baselen = offsetof(struct ieee80211_mgmt, u.probe_resp.variable);
 178                 beacon = false;
 179         } else {
 180                 baselen = offsetof(struct ieee80211_mgmt, u.beacon.variable);
 181                 elements = mgmt->u.beacon.variable;
 182                 beacon = true;
 183         }
 184
 185         if (baselen > skb->len)
 186                 return;
 187
 188         ieee802_11_parse_elems(elements, skb->len - baselen, &elems);
 189
 190         channel = ieee80211_get_channel(local->hw.wiphy, rx_status->freq);
 191
 192         if (!channel || channel->flags & IEEE80211_CHAN_DISABLED)
 193                 return;
 194
 195         bss = ieee80211_bss_info_update(local, rx_status,
 196                                         mgmt, skb->len, &elems,
 197                                         channel);
 198         if (bss)
 199                 ieee80211_rx_bss_put(local, bss);
 200 }
 201
 202 /* return false if no more work */
 203 static bool ieee80211_prep_hw_scan(struct ieee80211_local *local)
 204 {
 205         struct cfg80211_scan_request *req = local->scan_req;
 206         enum ieee80211_band band;
 207         int i, ielen, n_chans;
 208
 209         do {
 210                 if (local->hw_scan_band == IEEE80211_NUM_BANDS)
 211                         return false;
 212
 213                 band = local->hw_scan_band;
 214                 n_chans = 0;
 215                 for (i = 0; i < req->n_channels; i++) {
 216                         if (req->channels[i]->band == band) {
 217                                 local->hw_scan_req->channels[n_chans] =
 218                                                         req->channels[i];
 219                                 n_chans++;
 220                         }
 221                 }
 222
 223                 local->hw_scan_band++;
 224         } while (!n_chans);
 225
 226         local->hw_scan_req->n_channels = n_chans;
 227
 228         ielen = ieee80211_build_preq_ies(local, (u8 *)local->hw_scan_req->ie,
 229                                          local->hw_scan_ies_bufsize,
 230                                          req->ie, req->ie_len, band,
 231                                          req->rates[band], 0);
 232         local->hw_scan_req->ie_len = ielen;
 233         local->hw_scan_req->no_cck = req->no_cck;
 234
 235         return true;
 236 }
 237
 238 static void __ieee80211_scan_completed(struct ieee80211_hw *hw, bool aborted,
 239                                        bool was_hw_scan)
 240 {
 241         struct ieee80211_local *local = hw_to_local(hw);
 242
 243         lockdep_assert_held(&local->mtx);
 244
 245         /*
 246          * It's ok to abort a not-yet-running scan (that
 247          * we have one at all will be verified by checking
 248          * local->scan_req next), but not to complete it
 249          * successfully.
 250          */
 251         if (WARN_ON(!local->scanning && !aborted))
 252                 aborted = true;
 253
 254         if (WARN_ON(!local->scan_req))
 255                 return;
 256
 257         if (was_hw_scan && !aborted && ieee80211_prep_hw_scan(local)) {
 258                 int rc;
 259
 260                 rc = drv_hw_scan(local,
 261                         rcu_dereference_protected(local->scan_sdata,
 262                                                   lockdep_is_held(&local->mtx)),
 263                         local->hw_scan_req);
 264
 265                 if (rc == 0)
 266                         return;
 267         }
 268
 269         kfree(local->hw_scan_req);
 270         local->hw_scan_req = NULL;
 271
 272         if (local->scan_req != local->int_scan_req)
 273                 cfg80211_scan_done(local->scan_req, aborted);
 274         local->scan_req = NULL;
 275         rcu_assign_pointer(local->scan_sdata, NULL);
 276
 277         local->scanning = 0;
 278         local->scan_channel = NULL;
 279
 280         /* Set power back to normal operating levels. */
 281         ieee80211_hw_config(local, 0);
 282
 283         if (!was_hw_scan) {
 284                 ieee80211_configure_filter(local);
 285                 drv_sw_scan_complete(local);
 286                 ieee80211_offchannel_return(local);
 287         }
 288
 289         ieee80211_recalc_idle(local);
 290
 291         ieee80211_mlme_notify_scan_completed(local);
 292         ieee80211_ibss_notify_scan_completed(local);
 293         ieee80211_mesh_notify_scan_completed(local);
 294         ieee80211_start_next_roc(local);
 295 }
 296
 297 void ieee80211_scan_completed(struct ieee80211_hw *hw, bool aborted)
 298 {
 299         struct ieee80211_local *local = hw_to_local(hw);
 300
 301         trace_api_scan_completed(local, aborted);
 302
 303         set_bit(SCAN_COMPLETED, &local->scanning);
 304         if (aborted)
 305                 set_bit(SCAN_ABORTED, &local->scanning);
 306         ieee80211_queue_delayed_work(&local->hw, &local->scan_work, 0);
 307 }
 308 EXPORT_SYMBOL(ieee80211_scan_completed);
 309
 310 static int ieee80211_start_sw_scan(struct ieee80211_local *local)
 311 {
 312         /* Software scan is not supported in multi-channel cases */
 313         if (local->use_chanctx)
 314                 return -EOPNOTSUPP;
 315
 316         /*
 317          * Hardware/driver doesn't support hw_scan, so use software
 318          * scanning instead. First send a nullfunc frame with power save
 319          * bit on so that AP will buffer the frames for us while we are not
 320          * listening, then send probe requests to each channel and wait for
 321          * the responses. After all channels are scanned, tune back to the
 322          * original channel and send a nullfunc frame with power save bit
 323          * off to trigger the AP to send us all the buffered frames.
 324          *
 325          * Note that while local->sw_scanning is true everything else but
 326          * nullfunc frames and probe requests will be dropped in
 327          * ieee80211_tx_h_check_assoc().
 328          */
 329         drv_sw_scan_start(local);
 330
 331         local->leave_oper_channel_time = jiffies;
 332         local->next_scan_state = SCAN_DECISION;
 333         local->scan_channel_idx = 0;
 334
 335         ieee80211_offchannel_stop_vifs(local);
 336
 337         /* ensure nullfunc is transmitted before leaving operating channel */
 338         drv_flush(local, false);
 339
 340         ieee80211_configure_filter(local);
 341
 342         /* We need to set power level at maximum rate for scanning. */
 343         ieee80211_hw_config(local, 0);
 344
 345         ieee80211_queue_delayed_work(&local->hw,
 346                                      &local->scan_work, 0);
 347
 348         return 0;
 349 }
 350
 351 static bool ieee80211_can_scan(struct ieee80211_local *local,
 352                                struct ieee80211_sub_if_data *sdata)
 353 {
 354         if (local->radar_detect_enabled)
 355                 return false;
 356
 357         if (!list_empty(&local->roc_list))
 358                 return false;
 359
 360         if (sdata->vif.type == NL80211_IFTYPE_STATION &&
 361             sdata->u.mgd.flags & (IEEE80211_STA_BEACON_POLL |
 362                                   IEEE80211_STA_CONNECTION_POLL))
 363                 return false;
 364
 365         return true;
 366 }
 367
 368 void ieee80211_run_deferred_scan(struct ieee80211_local *local)
 369 {
 370         lockdep_assert_held(&local->mtx);
 371
 372         if (!local->scan_req || local->scanning)
 373                 return;
 374
 375         if (!ieee80211_can_scan(local,
 376                                 rcu_dereference_protected(
 377                                         local->scan_sdata,
 378                                         lockdep_is_held(&local->mtx))))
 379                 return;
 380
 381         ieee80211_queue_delayed_work(&local->hw, &local->scan_work,
 382                                      round_jiffies_relative(0));
 383 }
 384
 385 static void ieee80211_scan_state_send_probe(struct ieee80211_local *local,
 386                                             unsigned long *next_delay)
 387 {
 388         int i;
 389         struct ieee80211_sub_if_data *sdata;
 390         enum ieee80211_band band = local->hw.conf.channel->band;
 391         u32 tx_flags;
 392
 393         tx_flags = IEEE80211_TX_INTFL_OFFCHAN_TX_OK;
 394         if (local->scan_req->no_cck)
 395                 tx_flags |= IEEE80211_TX_CTL_NO_CCK_RATE;
 396
 397         sdata = rcu_dereference_protected(local->scan_sdata,
 398                                           lockdep_is_held(&local->mtx));
 399
 400         for (i = 0; i < local->scan_req->n_ssids; i++)
 401                 ieee80211_send_probe_req(
 402                         sdata, NULL,
 403                         local->scan_req->ssids[i].ssid,
 404                         local->scan_req->ssids[i].ssid_len,
 405                         local->scan_req->ie, local->scan_req->ie_len,
 406                         local->scan_req->rates[band], false,
 407                         tx_flags, local->hw.conf.channel, true);
 408
 409         /*
 410          * After sending probe requests, wait for probe responses
 411          * on the channel.
 412          */
 413         *next_delay = IEEE80211_CHANNEL_TIME;
 414         local->next_scan_state = SCAN_DECISION;
 415 }
 416
 417 static int __ieee80211_start_scan(struct ieee80211_sub_if_data *sdata,
 418                                   struct cfg80211_scan_request *req)
 419 {
 420         struct ieee80211_local *local = sdata->local;
 421         int rc;
 422
 423         lockdep_assert_held(&local->mtx);
 424
 425         if (local->scan_req)
 426                 return -EBUSY;
 427
 428         if (!ieee80211_can_scan(local, sdata)) {
 429                 /* wait for the work to finish/time out */
 430                 local->scan_req = req;
 431                 rcu_assign_pointer(local->scan_sdata, sdata);
 432                 return 0;
 433         }
 434
 435         if (local->ops->hw_scan) {
 436                 u8 *ies;
 437
 438                 local->hw_scan_ies_bufsize = 2 + IEEE80211_MAX_SSID_LEN +
 439                                              local->scan_ies_len +
 440                                              req->ie_len;
 441                 local->hw_scan_req = kmalloc(
 442                                 sizeof(*local->hw_scan_req) +
 443                                 req->n_channels * sizeof(req->channels[0]) +
 444                                 local->hw_scan_ies_bufsize, GFP_KERNEL);
 445                 if (!local->hw_scan_req)
 446                         return -ENOMEM;
 447
 448                 local->hw_scan_req->ssids = req->ssids;
 449                 local->hw_scan_req->n_ssids = req->n_ssids;
 450                 ies = (u8 *)local->hw_scan_req +
 451                         sizeof(*local->hw_scan_req) +
 452                         req->n_channels * sizeof(req->channels[0]);
 453                 local->hw_scan_req->ie = ies;
 454                 local->hw_scan_req->flags = req->flags;
 455
 456                 local->hw_scan_band = 0;
 457
 458                 /*
 459                  * After allocating local->hw_scan_req, we must
 460                  * go through until ieee80211_prep_hw_scan(), so
 461                  * anything that might be changed here and leave
 462                  * this function early must not go after this
 463                  * allocation.
 464                  */
 465         }
 466
 467         local->scan_req = req;
 468         rcu_assign_pointer(local->scan_sdata, sdata);
 469
 470         if (local->ops->hw_scan) {
 471                 __set_bit(SCAN_HW_SCANNING, &local->scanning);
 472         } else if ((req->n_channels == 1) &&
 473                    (req->channels[0] == local->_oper_channel)) {
 474                 /*
 475                  * If we are scanning only on the operating channel
 476                  * then we do not need to stop normal activities
 477                  */
 478                 unsigned long next_delay;
 479
 480                 __set_bit(SCAN_ONCHANNEL_SCANNING, &local->scanning);
 481
 482                 ieee80211_recalc_idle(local);
 483
 484                 /* Notify driver scan is starting, keep order of operations
 485                  * same as normal software scan, in case that matters. */
 486                 drv_sw_scan_start(local);
 487
 488                 ieee80211_configure_filter(local); /* accept probe-responses */
 489
 490                 /* We need to ensure power level is at max for scanning. */
 491                 ieee80211_hw_config(local, 0);
 492
 493                 if ((req->channels[0]->flags &
 494                      IEEE80211_CHAN_PASSIVE_SCAN) ||
 495                     !local->scan_req->n_ssids) {
 496                         next_delay = IEEE80211_PASSIVE_CHANNEL_TIME;
 497                 } else {
 498                         ieee80211_scan_state_send_probe(local, &next_delay);
 499                         next_delay = IEEE80211_CHANNEL_TIME;
 500                 }
 501
 502                 /* Now, just wait a bit and we are all done! */
 503                 ieee80211_queue_delayed_work(&local->hw, &local->scan_work,
 504                                              next_delay);
 505                 return 0;
 506         } else {
 507                 /* Do normal software scan */
 508                 __set_bit(SCAN_SW_SCANNING, &local->scanning);
 509         }
 510
 511         ieee80211_recalc_idle(local);
 512
 513         if (local->ops->hw_scan) {
 514                 WARN_ON(!ieee80211_prep_hw_scan(local));
 515                 rc = drv_hw_scan(local, sdata, local->hw_scan_req);
 516         } else
 517                 rc = ieee80211_start_sw_scan(local);
 518
 519         if (rc) {
 520                 kfree(local->hw_scan_req);
 521                 local->hw_scan_req = NULL;
 522                 local->scanning = 0;
 523
 524                 ieee80211_recalc_idle(local);
 525
 526                 local->scan_req = NULL;
 527                 rcu_assign_pointer(local->scan_sdata, NULL);
 528         }
 529
 530         return rc;
 531 }
 532
 533 static unsigned long
 534 ieee80211_scan_get_channel_time(struct ieee80211_channel *chan)
 535 {
 536         /*
 537          * TODO: channel switching also consumes quite some time,
 538          * add that delay as well to get a better estimation
 539          */
 540         if (chan->flags & IEEE80211_CHAN_PASSIVE_SCAN)
 541                 return IEEE80211_PASSIVE_CHANNEL_TIME;
 542         return IEEE80211_PROBE_DELAY + IEEE80211_CHANNEL_TIME;
 543 }
 544
 545 static void ieee80211_scan_state_decision(struct ieee80211_local *local,
 546                                           unsigned long *next_delay)
 547 {
 548         bool associated = false;
 549         bool tx_empty = true;
 550         bool bad_latency;
 551         struct ieee80211_sub_if_data *sdata;
 552         struct ieee80211_channel *next_chan;
 553         enum mac80211_scan_state next_scan_state;
 554
 555         /*
 556          * check if at least one STA interface is associated,
 557          * check if at least one STA interface has pending tx frames
 558          * and grab the lowest used beacon interval
 559          */
 560         mutex_lock(&local->iflist_mtx);
 561         list_for_each_entry(sdata, &local->interfaces, list) {
 562                 if (!ieee80211_sdata_running(sdata))
 563                         continue;
 564
 565                 if (sdata->vif.type == NL80211_IFTYPE_STATION) {
 566                         if (sdata->u.mgd.associated) {
 567                                 associated = true;
 568
 569                                 if (!qdisc_all_tx_empty(sdata->dev)) {
 570                                         tx_empty = false;
 571                                         break;
 572                                 }
 573                         }
 574                 }
 575         }
 576         mutex_unlock(&local->iflist_mtx);
 577
 578         next_chan = local->scan_req->channels[local->scan_channel_idx];
 579
 580         /*
 581          * we're currently scanning a different channel, let's
 582          * see if we can scan another channel without interfering
 583          * with the current traffic situation.
 584          *
 585          * Keep good latency, do not stay off-channel more than 125 ms.
 586          */
 587
 588         bad_latency = time_after(jiffies +
 589                                  ieee80211_scan_get_channel_time(next_chan),
 590                                  local->leave_oper_channel_time + HZ / 8);
 591
 592         if (associated && !tx_empty) {
 593                 if (local->scan_req->flags & NL80211_SCAN_FLAG_LOW_PRIORITY)
 594                         next_scan_state = SCAN_ABORT;
 595                 else
 596                         next_scan_state = SCAN_SUSPEND;
 597         } else if (associated && bad_latency) {
 598                 next_scan_state = SCAN_SUSPEND;
 599         } else {
 600                 next_scan_state = SCAN_SET_CHANNEL;
 601         }
 602
 603         local->next_scan_state = next_scan_state;
 604
 605         *next_delay = 0;
 606 }
 607
 608 static void ieee80211_scan_state_set_channel(struct ieee80211_local *local,
 609                                              unsigned long *next_delay)
 610 {
 611         int skip;
 612         struct ieee80211_channel *chan;
 613
 614         skip = 0;
 615         chan = local->scan_req->channels[local->scan_channel_idx];
 616
 617         local->scan_channel = chan;
 618
 619         if (ieee80211_hw_config(local, IEEE80211_CONF_CHANGE_CHANNEL))
 620                 skip = 1;
 621
 622         /* advance state machine to next channel/band */
 623         local->scan_channel_idx++;
 624
 625         if (skip) {
 626                 /* if we skip this channel return to the decision state */
 627                 local->next_scan_state = SCAN_DECISION;
 628                 return;
 629         }
 630
 631         /*
 632          * Probe delay is used to update the NAV, cf. 11.1.3.2.2
 633          * (which unfortunately doesn't say _why_ step a) is done,
 634          * but it waits for the probe delay or until a frame is
 635          * received - and the received frame would update the NAV).
 636          * For now, we do not support waiting until a frame is
 637          * received.
 638          *
 639          * In any case, it is not necessary for a passive scan.
 640          */
 641         if (chan->flags & IEEE80211_CHAN_PASSIVE_SCAN ||
 642             !local->scan_req->n_ssids) {
 643                 *next_delay = IEEE80211_PASSIVE_CHANNEL_TIME;
 644                 local->next_scan_state = SCAN_DECISION;
 645                 return;
 646         }
 647
 648         /* active scan, send probes */
 649         *next_delay = IEEE80211_PROBE_DELAY;
 650         local->next_scan_state = SCAN_SEND_PROBE;
 651 }
 652
 653 static void ieee80211_scan_state_suspend(struct ieee80211_local *local,
 654                                          unsigned long *next_delay)
 655 {
 656         /* switch back to the operating channel */
 657         local->scan_channel = NULL;
 658         ieee80211_hw_config(local, IEEE80211_CONF_CHANGE_CHANNEL);
 659
 660         /* disable PS */
 661         ieee80211_offchannel_return(local);
 662
 663         *next_delay = HZ / 5;
 664         /* afterwards, resume scan & go to next channel */
 665         local->next_scan_state = SCAN_RESUME;
 666 }
 667
 668 static void ieee80211_scan_state_resume(struct ieee80211_local *local,
 669                                         unsigned long *next_delay)
 670 {
 671         ieee80211_offchannel_stop_vifs(local);
 672
 673         if (local->ops->flush) {
 674                 drv_flush(local, false);
 675                 *next_delay = 0;
 676         } else
 677                 *next_delay = HZ / 10;
 678
 679         /* remember when we left the operating channel */
 680         local->leave_oper_channel_time = jiffies;
 681
 682         /* advance to the next channel to be scanned */
 683         local->next_scan_state = SCAN_SET_CHANNEL;
 684 }
 685
 686 void ieee80211_scan_work(struct work_struct *work)
 687 {
 688         struct ieee80211_local *local =
 689                 container_of(work, struct ieee80211_local, scan_work.work);
 690         struct ieee80211_sub_if_data *sdata;
 691         unsigned long next_delay = 0;
 692         bool aborted, hw_scan;
 693
 694         mutex_lock(&local->mtx);
 695
 696         sdata = rcu_dereference_protected(local->scan_sdata,
 697                                           lockdep_is_held(&local->mtx));
 698
 699         /* When scanning on-channel, the first-callback means completed. */
 700         if (test_bit(SCAN_ONCHANNEL_SCANNING, &local->scanning)) {
 701                 aborted = test_and_clear_bit(SCAN_ABORTED, &local->scanning);
 702                 goto out_complete;
 703         }
 704
 705         if (test_and_clear_bit(SCAN_COMPLETED, &local->scanning)) {
 706                 aborted = test_and_clear_bit(SCAN_ABORTED, &local->scanning);
 707                 goto out_complete;
 708         }
 709
 710         if (!sdata || !local->scan_req)
 711                 goto out;
 712
 713         if (local->scan_req && !local->scanning) {
 714                 struct cfg80211_scan_request *req = local->scan_req;
 715                 int rc;
 716
 717                 local->scan_req = NULL;
 718                 rcu_assign_pointer(local->scan_sdata, NULL);
 719
 720                 rc = __ieee80211_start_scan(sdata, req);
 721                 if (rc) {
 722                         /* need to complete scan in cfg80211 */
 723                         local->scan_req = req;
 724                         aborted = true;
 725                         goto out_complete;
 726                 } else
 727                         goto out;
 728         }
 729
 730         /*
 731          * Avoid re-scheduling when the sdata is going away.
 732          */
 733         if (!ieee80211_sdata_running(sdata)) {
 734                 aborted = true;
 735                 goto out_complete;
 736         }
 737
 738         /*
 739          * as long as no delay is required advance immediately
 740          * without scheduling a new work
 741          */
 742         do {
 743                 if (!ieee80211_sdata_running(sdata)) {
 744                         aborted = true;
 745                         goto out_complete;
 746                 }
 747
 748                 switch (local->next_scan_state) {
 749                 case SCAN_DECISION:
 750                         /* if no more bands/channels left, complete scan */
 751                         if (local->scan_channel_idx >= local->scan_req->n_channels) {
 752                                 aborted = false;
 753                                 goto out_complete;
 754                         }
 755                         ieee80211_scan_state_decision(local, &next_delay);
 756                         break;
 757                 case SCAN_SET_CHANNEL:
 758                         ieee80211_scan_state_set_channel(local, &next_delay);
 759                         break;
 760                 case SCAN_SEND_PROBE:
 761                         ieee80211_scan_state_send_probe(local, &next_delay);
 762                         break;
 763                 case SCAN_SUSPEND:
 764                         ieee80211_scan_state_suspend(local, &next_delay);
 765                         break;
 766                 case SCAN_RESUME:
 767                         ieee80211_scan_state_resume(local, &next_delay);
 768                         break;
 769                 case SCAN_ABORT:
 770                         aborted = true;
 771                         goto out_complete;
 772                 }
 773         } while (next_delay == 0);
 774
 775         ieee80211_queue_delayed_work(&local->hw, &local->scan_work, next_delay);
 776         goto out;
 777
 778 out_complete:
 779         hw_scan = test_bit(SCAN_HW_SCANNING, &local->scanning);
 780         __ieee80211_scan_completed(&local->hw, aborted, hw_scan);
 781 out:
 782         mutex_unlock(&local->mtx);
 783 }
 784
 785 int ieee80211_request_scan(struct ieee80211_sub_if_data *sdata,
 786                            struct cfg80211_scan_request *req)
 787 {
 788         int res;
 789
 790         mutex_lock(&sdata->local->mtx);
 791         res = __ieee80211_start_scan(sdata, req);
 792         mutex_unlock(&sdata->local->mtx);
 793
 794         return res;
 795 }
 796
 797 int ieee80211_request_ibss_scan(struct ieee80211_sub_if_data *sdata,
 798                                 const u8 *ssid, u8 ssid_len,
 799                                 struct ieee80211_channel *chan)
 800 {
 801         struct ieee80211_local *local = sdata->local;
 802         int ret = -EBUSY;
 803         enum ieee80211_band band;
 804
 805         mutex_lock(&local->mtx);
 806
 807         /* busy scanning */
 808         if (local->scan_req)
 809                 goto unlock;
 810
 811         /* fill internal scan request */
 812         if (!chan) {
 813                 int i, max_n;
 814                 int n_ch = 0;
 815
 816                 for (band = 0; band < IEEE80211_NUM_BANDS; band++) {
 817                         if (!local->hw.wiphy->bands[band])
 818                                 continue;
 819
 820                         max_n = local->hw.wiphy->bands[band]->n_channels;
 821                         for (i = 0; i < max_n; i++) {
 822                                 struct ieee80211_channel *tmp_ch =
 823                                     &local->hw.wiphy->bands[band]->channels[i];
 824
 825                                 if (tmp_ch->flags & (IEEE80211_CHAN_NO_IBSS |
 826                                                      IEEE80211_CHAN_DISABLED))
 827                                         continue;
 828
 829                                 local->int_scan_req->channels[n_ch] = tmp_ch;
 830                                 n_ch++;
 831                         }
 832                 }
 833
 834                 if (WARN_ON_ONCE(n_ch == 0))
 835                         goto unlock;
 836
 837                 local->int_scan_req->n_channels = n_ch;
 838         } else {
 839                 if (WARN_ON_ONCE(chan->flags & (IEEE80211_CHAN_NO_IBSS |
 840                                                 IEEE80211_CHAN_DISABLED)))
 841                         goto unlock;
 842
 843                 local->int_scan_req->channels[0] = chan;
 844                 local->int_scan_req->n_channels = 1;
 845         }
 846
 847         local->int_scan_req->ssids = &local->scan_ssid;
 848         local->int_scan_req->n_ssids = 1;
 849         memcpy(local->int_scan_req->ssids[0].ssid, ssid, IEEE80211_MAX_SSID_LEN);
 850         local->int_scan_req->ssids[0].ssid_len = ssid_len;
 851
 852         ret = __ieee80211_start_scan(sdata, sdata->local->int_scan_req);
 853  unlock:
 854         mutex_unlock(&local->mtx);
 855         return ret;
 856 }
 857
 858 /*
 859  * Only call this function when a scan can't be queued -- under RTNL.
 860  */
 861 void ieee80211_scan_cancel(struct ieee80211_local *local)
 862 {
 863         /*
 864          * We are canceling software scan, or deferred scan that was not
 865          * yet really started (see __ieee80211_start_scan ).
 866          *
 867          * Regarding hardware scan:
 868          * - we can not call  __ieee80211_scan_completed() as when
 869          *   SCAN_HW_SCANNING bit is set this function change
 870          *   local->hw_scan_req to operate on 5G band, what race with
 871          *   driver which can use local->hw_scan_req
 872          *
 873          * - we can not cancel scan_work since driver can schedule it
 874          *   by ieee80211_scan_completed(..., true) to finish scan
 875          *
 876          * Hence we only call the cancel_hw_scan() callback, but the low-level
 877          * driver is still responsible for calling ieee80211_scan_completed()
 878          * after the scan was completed/aborted.
 879          */
 880
 881         mutex_lock(&local->mtx);
 882         if (!local->scan_req)
 883                 goto out;
 884
 885         if (test_bit(SCAN_HW_SCANNING, &local->scanning)) {
 886                 if (local->ops->cancel_hw_scan)
 887                         drv_cancel_hw_scan(local,
 888                                 rcu_dereference_protected(local->scan_sdata,
 889                                                 lockdep_is_held(&local->mtx)));
 890                 goto out;
 891         }
 892
 893         /*
 894          * If the work is currently running, it must be blocked on
 895          * the mutex, but we'll set scan_sdata = NULL and it'll
 896          * simply exit once it acquires the mutex.
 897          */
 898         cancel_delayed_work(&local->scan_work);
 899         /* and clean up */
 900         __ieee80211_scan_completed(&local->hw, true, false);
 901 out:
 902         mutex_unlock(&local->mtx);
 903 }
 904
 905 int ieee80211_request_sched_scan_start(struct ieee80211_sub_if_data *sdata,
 906                                        struct cfg80211_sched_scan_request *req)
 907 {
 908         struct ieee80211_local *local = sdata->local;
 909         struct ieee80211_sched_scan_ies sched_scan_ies = {};
 910         int ret, i, iebufsz;
 911
 912         iebufsz = 2 + IEEE80211_MAX_SSID_LEN +
 913                   local->scan_ies_len + req->ie_len;
 914
 915         mutex_lock(&local->mtx);
 916
 917         if (rcu_access_pointer(local->sched_scan_sdata)) {
 918                 ret = -EBUSY;
 919                 goto out;
 920         }
 921
 922         if (!local->ops->sched_scan_start) {
 923                 ret = -ENOTSUPP;
 924                 goto out;
 925         }
 926
 927         for (i = 0; i < IEEE80211_NUM_BANDS; i++) {
 928                 if (!local->hw.wiphy->bands[i])
 929                         continue;
 930
 931                 sched_scan_ies.ie[i] = kzalloc(iebufsz, GFP_KERNEL);
 932                 if (!sched_scan_ies.ie[i]) {
 933                         ret = -ENOMEM;
 934                         goto out_free;
 935                 }
 936
 937                 sched_scan_ies.len[i] =
 938                         ieee80211_build_preq_ies(local, sched_scan_ies.ie[i],
 939                                                  iebufsz, req->ie, req->ie_len,
 940                                                  i, (u32) -1, 0);
 941         }
 942
 943         ret = drv_sched_scan_start(local, sdata, req, &sched_scan_ies);
 944         if (ret == 0)
 945                 rcu_assign_pointer(local->sched_scan_sdata, sdata);
 946
 947 out_free:
 948         while (i > 0)
 949                 kfree(sched_scan_ies.ie[--i]);
 950 out:
 951         mutex_unlock(&local->mtx);
 952         return ret;
 953 }
 954
 955 int ieee80211_request_sched_scan_stop(struct ieee80211_sub_if_data *sdata)
 956 {
 957         struct ieee80211_local *local = sdata->local;
 958         int ret = 0;
 959
 960         mutex_lock(&local->mtx);
 961
 962         if (!local->ops->sched_scan_stop) {
 963                 ret = -ENOTSUPP;
 964                 goto out;
 965         }
 966
 967         if (rcu_access_pointer(local->sched_scan_sdata))
 968                 drv_sched_scan_stop(local, sdata);
 969
 970 out:
 971         mutex_unlock(&local->mtx);
 972
 973         return ret;
 974 }
 975
 976 void ieee80211_sched_scan_results(struct ieee80211_hw *hw)
 977 {
 978         struct ieee80211_local *local = hw_to_local(hw);
 979
 980         trace_api_sched_scan_results(local);
 981
 982         cfg80211_sched_scan_results(hw->wiphy);
 983 }
 984 EXPORT_SYMBOL(ieee80211_sched_scan_results);
 985
 986 void ieee80211_sched_scan_stopped_work(struct work_struct *work)
 987 {
 988         struct ieee80211_local *local =
 989                 container_of(work, struct ieee80211_local,
 990                              sched_scan_stopped_work);
 991
 992         mutex_lock(&local->mtx);
 993
 994         if (!rcu_access_pointer(local->sched_scan_sdata)) {
 995                 mutex_unlock(&local->mtx);
 996                 return;
 997         }
 998
 999         rcu_assign_pointer(local->sched_scan_sdata, NULL);
1000
1001         mutex_unlock(&local->mtx);
1002
1003         cfg80211_sched_scan_stopped(local->hw.wiphy);
1004 }
1005
1006 void ieee80211_sched_scan_stopped(struct ieee80211_hw *hw)
1007 {
1008         struct ieee80211_local *local = hw_to_local(hw);
1009
1010         trace_api_sched_scan_stopped(local);
1011
1012         ieee80211_queue_work(&local->hw, &local->sched_scan_stopped_work);
1013 }
1014 EXPORT_SYMBOL(ieee80211_sched_scan_stopped);