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->parse_error ||
 102                                 !(bss->valid_data & IEEE80211_BSS_VALID_ERP))) {
 103                 bss->erp_value = elems->erp_info[0];
 104                 bss->has_erp_value = true;
 105                 if (!elems->parse_error)
 106                         bss->valid_data |= IEEE80211_BSS_VALID_ERP;
 107         }
 108
 109         /* replace old supported rates if we get new values */
 110         if (!elems->parse_error ||
 111             !(bss->valid_data & IEEE80211_BSS_VALID_RATES)) {
 112                 srlen = 0;
 113                 if (elems->supp_rates) {
 114                         clen = IEEE80211_MAX_SUPP_RATES;
 115                         if (clen > elems->supp_rates_len)
 116                                 clen = elems->supp_rates_len;
 117                         memcpy(bss->supp_rates, elems->supp_rates, clen);
 118                         srlen += clen;
 119                 }
 120                 if (elems->ext_supp_rates) {
 121                         clen = IEEE80211_MAX_SUPP_RATES - srlen;
 122                         if (clen > elems->ext_supp_rates_len)
 123                                 clen = elems->ext_supp_rates_len;
 124                         memcpy(bss->supp_rates + srlen, elems->ext_supp_rates,
 125                                clen);
 126                         srlen += clen;
 127                 }
 128                 if (srlen) {
 129                         bss->supp_rates_len = srlen;
 130                         if (!elems->parse_error)
 131                                 bss->valid_data |= IEEE80211_BSS_VALID_RATES;
 132                 }
 133         }
 134
 135         if (!elems->parse_error ||
 136             !(bss->valid_data & IEEE80211_BSS_VALID_WMM)) {
 137                 bss->wmm_used = elems->wmm_param || elems->wmm_info;
 138                 bss->uapsd_supported = is_uapsd_supported(elems);
 139                 if (!elems->parse_error)
 140                         bss->valid_data |= IEEE80211_BSS_VALID_WMM;
 141         }
 142
 143         if (beacon) {
 144                 struct ieee80211_supported_band *sband =
 145                         local->hw.wiphy->bands[rx_status->band];
 146                 if (!(rx_status->flag & RX_FLAG_HT) &&
 147                     !(rx_status->flag & RX_FLAG_VHT))
 148                         bss->beacon_rate =
 149                                 &sband->bitrates[rx_status->rate_idx];
 150         }
 151
 152         return bss;
 153 }
 154
 155 void ieee80211_scan_rx(struct ieee80211_local *local, struct sk_buff *skb)
 156 {
 157         struct ieee80211_rx_status *rx_status = IEEE80211_SKB_RXCB(skb);
 158         struct ieee80211_sub_if_data *sdata1, *sdata2;
 159         struct ieee80211_mgmt *mgmt = (void *)skb->data;
 160         struct ieee80211_bss *bss;
 161         u8 *elements;
 162         struct ieee80211_channel *channel;
 163         size_t baselen;
 164         struct ieee802_11_elems elems;
 165
 166         if (skb->len < 24 ||
 167             (!ieee80211_is_probe_resp(mgmt->frame_control) &&
 168              !ieee80211_is_beacon(mgmt->frame_control)))
 169                 return;
 170
 171         sdata1 = rcu_dereference(local->scan_sdata);
 172         sdata2 = rcu_dereference(local->sched_scan_sdata);
 173
 174         if (likely(!sdata1 && !sdata2))
 175                 return;
 176
 177         if (ieee80211_is_probe_resp(mgmt->frame_control)) {
 178                 /* ignore ProbeResp to foreign address */
 179                 if ((!sdata1 || !ether_addr_equal(mgmt->da, sdata1->vif.addr)) &&
 180                     (!sdata2 || !ether_addr_equal(mgmt->da, sdata2->vif.addr)))
 181                         return;
 182
 183                 elements = mgmt->u.probe_resp.variable;
 184                 baselen = offsetof(struct ieee80211_mgmt, u.probe_resp.variable);
 185         } else {
 186                 baselen = offsetof(struct ieee80211_mgmt, u.beacon.variable);
 187                 elements = mgmt->u.beacon.variable;
 188         }
 189
 190         if (baselen > skb->len)
 191                 return;
 192
 193         ieee802_11_parse_elems(elements, skb->len - baselen, false, &elems);
 194
 195         channel = ieee80211_get_channel(local->hw.wiphy, rx_status->freq);
 196
 197         if (!channel || channel->flags & IEEE80211_CHAN_DISABLED)
 198                 return;
 199
 200         bss = ieee80211_bss_info_update(local, rx_status,
 201                                         mgmt, skb->len, &elems,
 202                                         channel);
 203         if (bss)
 204                 ieee80211_rx_bss_put(local, bss);
 205 }
 206
 207 static void
 208 ieee80211_prepare_scan_chandef(struct cfg80211_chan_def *chandef,
 209                                enum nl80211_bss_scan_width scan_width)
 210 {
 211         memset(chandef, 0, sizeof(*chandef));
 212         switch (scan_width) {
 213         case NL80211_BSS_CHAN_WIDTH_5:
 214                 chandef->width = NL80211_CHAN_WIDTH_5;
 215                 break;
 216         case NL80211_BSS_CHAN_WIDTH_10:
 217                 chandef->width = NL80211_CHAN_WIDTH_10;
 218                 break;
 219         default:
 220                 chandef->width = NL80211_CHAN_WIDTH_20_NOHT;
 221                 break;
 222         }
 223 }
 224
 225 /* return false if no more work */
 226 static bool ieee80211_prep_hw_scan(struct ieee80211_local *local)
 227 {
 228         struct cfg80211_scan_request *req = local->scan_req;
 229         struct cfg80211_chan_def chandef;
 230         enum ieee80211_band band;
 231         int i, ielen, n_chans;
 232
 233         do {
 234                 if (local->hw_scan_band == IEEE80211_NUM_BANDS)
 235                         return false;
 236
 237                 band = local->hw_scan_band;
 238                 n_chans = 0;
 239                 for (i = 0; i < req->n_channels; i++) {
 240                         if (req->channels[i]->band == band) {
 241                                 local->hw_scan_req->channels[n_chans] =
 242                                                         req->channels[i];
 243                                 n_chans++;
 244                         }
 245                 }
 246
 247                 local->hw_scan_band++;
 248         } while (!n_chans);
 249
 250         local->hw_scan_req->n_channels = n_chans;
 251         ieee80211_prepare_scan_chandef(&chandef, req->scan_width);
 252
 253         ielen = ieee80211_build_preq_ies(local, (u8 *)local->hw_scan_req->ie,
 254                                          local->hw_scan_ies_bufsize,
 255                                          req->ie, req->ie_len, band,
 256                                          req->rates[band], &chandef);
 257         local->hw_scan_req->ie_len = ielen;
 258         local->hw_scan_req->no_cck = req->no_cck;
 259
 260         return true;
 261 }
 262
 263 static void __ieee80211_scan_completed(struct ieee80211_hw *hw, bool aborted,
 264                                        bool was_hw_scan)
 265 {
 266         struct ieee80211_local *local = hw_to_local(hw);
 267
 268         lockdep_assert_held(&local->mtx);
 269
 270         /*
 271          * It's ok to abort a not-yet-running scan (that
 272          * we have one at all will be verified by checking
 273          * local->scan_req next), but not to complete it
 274          * successfully.
 275          */
 276         if (WARN_ON(!local->scanning && !aborted))
 277                 aborted = true;
 278
 279         if (WARN_ON(!local->scan_req))
 280                 return;
 281
 282         if (was_hw_scan && !aborted && ieee80211_prep_hw_scan(local)) {
 283                 int rc;
 284
 285                 rc = drv_hw_scan(local,
 286                         rcu_dereference_protected(local->scan_sdata,
 287                                                   lockdep_is_held(&local->mtx)),
 288                         local->hw_scan_req);
 289
 290                 if (rc == 0)
 291                         return;
 292         }
 293
 294         kfree(local->hw_scan_req);
 295         local->hw_scan_req = NULL;
 296
 297         if (local->scan_req != local->int_scan_req)
 298                 cfg80211_scan_done(local->scan_req, aborted);
 299         local->scan_req = NULL;
 300         rcu_assign_pointer(local->scan_sdata, NULL);
 301
 302         local->scanning = 0;
 303         local->scan_channel = NULL;
 304
 305         /* Set power back to normal operating levels. */
 306         ieee80211_hw_config(local, 0);
 307
 308         if (!was_hw_scan) {
 309                 ieee80211_configure_filter(local);
 310                 drv_sw_scan_complete(local);
 311                 ieee80211_offchannel_return(local);
 312         }
 313
 314         ieee80211_recalc_idle(local);
 315
 316         ieee80211_mlme_notify_scan_completed(local);
 317         ieee80211_ibss_notify_scan_completed(local);
 318         ieee80211_mesh_notify_scan_completed(local);
 319         ieee80211_start_next_roc(local);
 320 }
 321
 322 void ieee80211_scan_completed(struct ieee80211_hw *hw, bool aborted)
 323 {
 324         struct ieee80211_local *local = hw_to_local(hw);
 325
 326         trace_api_scan_completed(local, aborted);
 327
 328         set_bit(SCAN_COMPLETED, &local->scanning);
 329         if (aborted)
 330                 set_bit(SCAN_ABORTED, &local->scanning);
 331         ieee80211_queue_delayed_work(&local->hw, &local->scan_work, 0);
 332 }
 333 EXPORT_SYMBOL(ieee80211_scan_completed);
 334
 335 static int ieee80211_start_sw_scan(struct ieee80211_local *local)
 336 {
 337         /* Software scan is not supported in multi-channel cases */
 338         if (local->use_chanctx)
 339                 return -EOPNOTSUPP;
 340
 341         /*
 342          * Hardware/driver doesn't support hw_scan, so use software
 343          * scanning instead. First send a nullfunc frame with power save
 344          * bit on so that AP will buffer the frames for us while we are not
 345          * listening, then send probe requests to each channel and wait for
 346          * the responses. After all channels are scanned, tune back to the
 347          * original channel and send a nullfunc frame with power save bit
 348          * off to trigger the AP to send us all the buffered frames.
 349          *
 350          * Note that while local->sw_scanning is true everything else but
 351          * nullfunc frames and probe requests will be dropped in
 352          * ieee80211_tx_h_check_assoc().
 353          */
 354         drv_sw_scan_start(local);
 355
 356         local->leave_oper_channel_time = jiffies;
 357         local->next_scan_state = SCAN_DECISION;
 358         local->scan_channel_idx = 0;
 359
 360         ieee80211_offchannel_stop_vifs(local);
 361
 362         /* ensure nullfunc is transmitted before leaving operating channel */
 363         ieee80211_flush_queues(local, NULL);
 364
 365         ieee80211_configure_filter(local);
 366
 367         /* We need to set power level at maximum rate for scanning. */
 368         ieee80211_hw_config(local, 0);
 369
 370         ieee80211_queue_delayed_work(&local->hw,
 371                                      &local->scan_work, 0);
 372
 373         return 0;
 374 }
 375
 376 static bool ieee80211_can_scan(struct ieee80211_local *local,
 377                                struct ieee80211_sub_if_data *sdata)
 378 {
 379         if (local->radar_detect_enabled)
 380                 return false;
 381
 382         if (!list_empty(&local->roc_list))
 383                 return false;
 384
 385         if (sdata->vif.type == NL80211_IFTYPE_STATION &&
 386             sdata->u.mgd.flags & (IEEE80211_STA_BEACON_POLL |
 387                                   IEEE80211_STA_CONNECTION_POLL))
 388                 return false;
 389
 390         return true;
 391 }
 392
 393 void ieee80211_run_deferred_scan(struct ieee80211_local *local)
 394 {
 395         lockdep_assert_held(&local->mtx);
 396
 397         if (!local->scan_req || local->scanning)
 398                 return;
 399
 400         if (!ieee80211_can_scan(local,
 401                                 rcu_dereference_protected(
 402                                         local->scan_sdata,
 403                                         lockdep_is_held(&local->mtx))))
 404                 return;
 405
 406         ieee80211_queue_delayed_work(&local->hw, &local->scan_work,
 407                                      round_jiffies_relative(0));
 408 }
 409
 410 static void ieee80211_scan_state_send_probe(struct ieee80211_local *local,
 411                                             unsigned long *next_delay)
 412 {
 413         int i;
 414         struct ieee80211_sub_if_data *sdata;
 415         enum ieee80211_band band = local->hw.conf.chandef.chan->band;
 416         u32 tx_flags;
 417
 418         tx_flags = IEEE80211_TX_INTFL_OFFCHAN_TX_OK;
 419         if (local->scan_req->no_cck)
 420                 tx_flags |= IEEE80211_TX_CTL_NO_CCK_RATE;
 421
 422         sdata = rcu_dereference_protected(local->scan_sdata,
 423                                           lockdep_is_held(&local->mtx));
 424
 425         for (i = 0; i < local->scan_req->n_ssids; i++)
 426                 ieee80211_send_probe_req(
 427                         sdata, NULL,
 428                         local->scan_req->ssids[i].ssid,
 429                         local->scan_req->ssids[i].ssid_len,
 430                         local->scan_req->ie, local->scan_req->ie_len,
 431                         local->scan_req->rates[band], false,
 432                         tx_flags, local->hw.conf.chandef.chan, true);
 433
 434         /*
 435          * After sending probe requests, wait for probe responses
 436          * on the channel.
 437          */
 438         *next_delay = IEEE80211_CHANNEL_TIME;
 439         local->next_scan_state = SCAN_DECISION;
 440 }
 441
 442 static int __ieee80211_start_scan(struct ieee80211_sub_if_data *sdata,
 443                                   struct cfg80211_scan_request *req)
 444 {
 445         struct ieee80211_local *local = sdata->local;
 446         int rc;
 447
 448         lockdep_assert_held(&local->mtx);
 449
 450         if (local->scan_req)
 451                 return -EBUSY;
 452
 453         if (!ieee80211_can_scan(local, sdata)) {
 454                 /* wait for the work to finish/time out */
 455                 local->scan_req = req;
 456                 rcu_assign_pointer(local->scan_sdata, sdata);
 457                 return 0;
 458         }
 459
 460         if (local->ops->hw_scan) {
 461                 u8 *ies;
 462
 463                 local->hw_scan_ies_bufsize = 2 + IEEE80211_MAX_SSID_LEN +
 464                                              local->scan_ies_len +
 465                                              req->ie_len;
 466                 local->hw_scan_req = kmalloc(
 467                                 sizeof(*local->hw_scan_req) +
 468                                 req->n_channels * sizeof(req->channels[0]) +
 469                                 local->hw_scan_ies_bufsize, GFP_KERNEL);
 470                 if (!local->hw_scan_req)
 471                         return -ENOMEM;
 472
 473                 local->hw_scan_req->ssids = req->ssids;
 474                 local->hw_scan_req->n_ssids = req->n_ssids;
 475                 ies = (u8 *)local->hw_scan_req +
 476                         sizeof(*local->hw_scan_req) +
 477                         req->n_channels * sizeof(req->channels[0]);
 478                 local->hw_scan_req->ie = ies;
 479                 local->hw_scan_req->flags = req->flags;
 480
 481                 local->hw_scan_band = 0;
 482
 483                 /*
 484                  * After allocating local->hw_scan_req, we must
 485                  * go through until ieee80211_prep_hw_scan(), so
 486                  * anything that might be changed here and leave
 487                  * this function early must not go after this
 488                  * allocation.
 489                  */
 490         }
 491
 492         local->scan_req = req;
 493         rcu_assign_pointer(local->scan_sdata, sdata);
 494
 495         if (local->ops->hw_scan) {
 496                 __set_bit(SCAN_HW_SCANNING, &local->scanning);
 497         } else if ((req->n_channels == 1) &&
 498                    (req->channels[0] == local->_oper_chandef.chan)) {
 499                 /*
 500                  * If we are scanning only on the operating channel
 501                  * then we do not need to stop normal activities
 502                  */
 503                 unsigned long next_delay;
 504
 505                 __set_bit(SCAN_ONCHANNEL_SCANNING, &local->scanning);
 506
 507                 ieee80211_recalc_idle(local);
 508
 509                 /* Notify driver scan is starting, keep order of operations
 510                  * same as normal software scan, in case that matters. */
 511                 drv_sw_scan_start(local);
 512
 513                 ieee80211_configure_filter(local); /* accept probe-responses */
 514
 515                 /* We need to ensure power level is at max for scanning. */
 516                 ieee80211_hw_config(local, 0);
 517
 518                 if ((req->channels[0]->flags &
 519                      IEEE80211_CHAN_PASSIVE_SCAN) ||
 520                     !local->scan_req->n_ssids) {
 521                         next_delay = IEEE80211_PASSIVE_CHANNEL_TIME;
 522                 } else {
 523                         ieee80211_scan_state_send_probe(local, &next_delay);
 524                         next_delay = IEEE80211_CHANNEL_TIME;
 525                 }
 526
 527                 /* Now, just wait a bit and we are all done! */
 528                 ieee80211_queue_delayed_work(&local->hw, &local->scan_work,
 529                                              next_delay);
 530                 return 0;
 531         } else {
 532                 /* Do normal software scan */
 533                 __set_bit(SCAN_SW_SCANNING, &local->scanning);
 534         }
 535
 536         ieee80211_recalc_idle(local);
 537
 538         if (local->ops->hw_scan) {
 539                 WARN_ON(!ieee80211_prep_hw_scan(local));
 540                 rc = drv_hw_scan(local, sdata, local->hw_scan_req);
 541         } else
 542                 rc = ieee80211_start_sw_scan(local);
 543
 544         if (rc) {
 545                 kfree(local->hw_scan_req);
 546                 local->hw_scan_req = NULL;
 547                 local->scanning = 0;
 548
 549                 ieee80211_recalc_idle(local);
 550
 551                 local->scan_req = NULL;
 552                 rcu_assign_pointer(local->scan_sdata, NULL);
 553         }
 554
 555         return rc;
 556 }
 557
 558 static unsigned long
 559 ieee80211_scan_get_channel_time(struct ieee80211_channel *chan)
 560 {
 561         /*
 562          * TODO: channel switching also consumes quite some time,
 563          * add that delay as well to get a better estimation
 564          */
 565         if (chan->flags & IEEE80211_CHAN_PASSIVE_SCAN)
 566                 return IEEE80211_PASSIVE_CHANNEL_TIME;
 567         return IEEE80211_PROBE_DELAY + IEEE80211_CHANNEL_TIME;
 568 }
 569
 570 static void ieee80211_scan_state_decision(struct ieee80211_local *local,
 571                                           unsigned long *next_delay)
 572 {
 573         bool associated = false;
 574         bool tx_empty = true;
 575         bool bad_latency;
 576         struct ieee80211_sub_if_data *sdata;
 577         struct ieee80211_channel *next_chan;
 578         enum mac80211_scan_state next_scan_state;
 579
 580         /*
 581          * check if at least one STA interface is associated,
 582          * check if at least one STA interface has pending tx frames
 583          * and grab the lowest used beacon interval
 584          */
 585         mutex_lock(&local->iflist_mtx);
 586         list_for_each_entry(sdata, &local->interfaces, list) {
 587                 if (!ieee80211_sdata_running(sdata))
 588                         continue;
 589
 590                 if (sdata->vif.type == NL80211_IFTYPE_STATION) {
 591                         if (sdata->u.mgd.associated) {
 592                                 associated = true;
 593
 594                                 if (!qdisc_all_tx_empty(sdata->dev)) {
 595                                         tx_empty = false;
 596                                         break;
 597                                 }
 598                         }
 599                 }
 600         }
 601         mutex_unlock(&local->iflist_mtx);
 602
 603         next_chan = local->scan_req->channels[local->scan_channel_idx];
 604
 605         /*
 606          * we're currently scanning a different channel, let's
 607          * see if we can scan another channel without interfering
 608          * with the current traffic situation.
 609          *
 610          * Keep good latency, do not stay off-channel more than 125 ms.
 611          */
 612
 613         bad_latency = time_after(jiffies +
 614                                  ieee80211_scan_get_channel_time(next_chan),
 615                                  local->leave_oper_channel_time + HZ / 8);
 616
 617         if (associated && !tx_empty) {
 618                 if (local->scan_req->flags & NL80211_SCAN_FLAG_LOW_PRIORITY)
 619                         next_scan_state = SCAN_ABORT;
 620                 else
 621                         next_scan_state = SCAN_SUSPEND;
 622         } else if (associated && bad_latency) {
 623                 next_scan_state = SCAN_SUSPEND;
 624         } else {
 625                 next_scan_state = SCAN_SET_CHANNEL;
 626         }
 627
 628         local->next_scan_state = next_scan_state;
 629
 630         *next_delay = 0;
 631 }
 632
 633 static void ieee80211_scan_state_set_channel(struct ieee80211_local *local,
 634                                              unsigned long *next_delay)
 635 {
 636         int skip;
 637         struct ieee80211_channel *chan;
 638
 639         skip = 0;
 640         chan = local->scan_req->channels[local->scan_channel_idx];
 641
 642         local->scan_channel = chan;
 643
 644         if (ieee80211_hw_config(local, IEEE80211_CONF_CHANGE_CHANNEL))
 645                 skip = 1;
 646
 647         /* advance state machine to next channel/band */
 648         local->scan_channel_idx++;
 649
 650         if (skip) {
 651                 /* if we skip this channel return to the decision state */
 652                 local->next_scan_state = SCAN_DECISION;
 653                 return;
 654         }
 655
 656         /*
 657          * Probe delay is used to update the NAV, cf. 11.1.3.2.2
 658          * (which unfortunately doesn't say _why_ step a) is done,
 659          * but it waits for the probe delay or until a frame is
 660          * received - and the received frame would update the NAV).
 661          * For now, we do not support waiting until a frame is
 662          * received.
 663          *
 664          * In any case, it is not necessary for a passive scan.
 665          */
 666         if (chan->flags & IEEE80211_CHAN_PASSIVE_SCAN ||
 667             !local->scan_req->n_ssids) {
 668                 *next_delay = IEEE80211_PASSIVE_CHANNEL_TIME;
 669                 local->next_scan_state = SCAN_DECISION;
 670                 return;
 671         }
 672
 673         /* active scan, send probes */
 674         *next_delay = IEEE80211_PROBE_DELAY;
 675         local->next_scan_state = SCAN_SEND_PROBE;
 676 }
 677
 678 static void ieee80211_scan_state_suspend(struct ieee80211_local *local,
 679                                          unsigned long *next_delay)
 680 {
 681         /* switch back to the operating channel */
 682         local->scan_channel = NULL;
 683         ieee80211_hw_config(local, IEEE80211_CONF_CHANGE_CHANNEL);
 684
 685         /* disable PS */
 686         ieee80211_offchannel_return(local);
 687
 688         *next_delay = HZ / 5;
 689         /* afterwards, resume scan & go to next channel */
 690         local->next_scan_state = SCAN_RESUME;
 691 }
 692
 693 static void ieee80211_scan_state_resume(struct ieee80211_local *local,
 694                                         unsigned long *next_delay)
 695 {
 696         ieee80211_offchannel_stop_vifs(local);
 697
 698         if (local->ops->flush) {
 699                 ieee80211_flush_queues(local, NULL);
 700                 *next_delay = 0;
 701         } else
 702                 *next_delay = HZ / 10;
 703
 704         /* remember when we left the operating channel */
 705         local->leave_oper_channel_time = jiffies;
 706
 707         /* advance to the next channel to be scanned */
 708         local->next_scan_state = SCAN_SET_CHANNEL;
 709 }
 710
 711 void ieee80211_scan_work(struct work_struct *work)
 712 {
 713         struct ieee80211_local *local =
 714                 container_of(work, struct ieee80211_local, scan_work.work);
 715         struct ieee80211_sub_if_data *sdata;
 716         unsigned long next_delay = 0;
 717         bool aborted, hw_scan;
 718
 719         mutex_lock(&local->mtx);
 720
 721         sdata = rcu_dereference_protected(local->scan_sdata,
 722                                           lockdep_is_held(&local->mtx));
 723
 724         /* When scanning on-channel, the first-callback means completed. */
 725         if (test_bit(SCAN_ONCHANNEL_SCANNING, &local->scanning)) {
 726                 aborted = test_and_clear_bit(SCAN_ABORTED, &local->scanning);
 727                 goto out_complete;
 728         }
 729
 730         if (test_and_clear_bit(SCAN_COMPLETED, &local->scanning)) {
 731                 aborted = test_and_clear_bit(SCAN_ABORTED, &local->scanning);
 732                 goto out_complete;
 733         }
 734
 735         if (!sdata || !local->scan_req)
 736                 goto out;
 737
 738         if (local->scan_req && !local->scanning) {
 739                 struct cfg80211_scan_request *req = local->scan_req;
 740                 int rc;
 741
 742                 local->scan_req = NULL;
 743                 rcu_assign_pointer(local->scan_sdata, NULL);
 744
 745                 rc = __ieee80211_start_scan(sdata, req);
 746                 if (rc) {
 747                         /* need to complete scan in cfg80211 */
 748                         local->scan_req = req;
 749                         aborted = true;
 750                         goto out_complete;
 751                 } else
 752                         goto out;
 753         }
 754
 755         /*
 756          * Avoid re-scheduling when the sdata is going away.
 757          */
 758         if (!ieee80211_sdata_running(sdata)) {
 759                 aborted = true;
 760                 goto out_complete;
 761         }
 762
 763         /*
 764          * as long as no delay is required advance immediately
 765          * without scheduling a new work
 766          */
 767         do {
 768                 if (!ieee80211_sdata_running(sdata)) {
 769                         aborted = true;
 770                         goto out_complete;
 771                 }
 772
 773                 switch (local->next_scan_state) {
 774                 case SCAN_DECISION:
 775                         /* if no more bands/channels left, complete scan */
 776                         if (local->scan_channel_idx >= local->scan_req->n_channels) {
 777                                 aborted = false;
 778                                 goto out_complete;
 779                         }
 780                         ieee80211_scan_state_decision(local, &next_delay);
 781                         break;
 782                 case SCAN_SET_CHANNEL:
 783                         ieee80211_scan_state_set_channel(local, &next_delay);
 784                         break;
 785                 case SCAN_SEND_PROBE:
 786                         ieee80211_scan_state_send_probe(local, &next_delay);
 787                         break;
 788                 case SCAN_SUSPEND:
 789                         ieee80211_scan_state_suspend(local, &next_delay);
 790                         break;
 791                 case SCAN_RESUME:
 792                         ieee80211_scan_state_resume(local, &next_delay);
 793                         break;
 794                 case SCAN_ABORT:
 795                         aborted = true;
 796                         goto out_complete;
 797                 }
 798         } while (next_delay == 0);
 799
 800         ieee80211_queue_delayed_work(&local->hw, &local->scan_work, next_delay);
 801         goto out;
 802
 803 out_complete:
 804         hw_scan = test_bit(SCAN_HW_SCANNING, &local->scanning);
 805         __ieee80211_scan_completed(&local->hw, aborted, hw_scan);
 806 out:
 807         mutex_unlock(&local->mtx);
 808 }
 809
 810 int ieee80211_request_scan(struct ieee80211_sub_if_data *sdata,
 811                            struct cfg80211_scan_request *req)
 812 {
 813         int res;
 814
 815         mutex_lock(&sdata->local->mtx);
 816         res = __ieee80211_start_scan(sdata, req);
 817         mutex_unlock(&sdata->local->mtx);
 818
 819         return res;
 820 }
 821
 822 int ieee80211_request_ibss_scan(struct ieee80211_sub_if_data *sdata,
 823                                 const u8 *ssid, u8 ssid_len,
 824                                 struct ieee80211_channel *chan)
 825 {
 826         struct ieee80211_local *local = sdata->local;
 827         int ret = -EBUSY;
 828         enum ieee80211_band band;
 829
 830         mutex_lock(&local->mtx);
 831
 832         /* busy scanning */
 833         if (local->scan_req)
 834                 goto unlock;
 835
 836         /* fill internal scan request */
 837         if (!chan) {
 838                 int i, max_n;
 839                 int n_ch = 0;
 840
 841                 for (band = 0; band < IEEE80211_NUM_BANDS; band++) {
 842                         if (!local->hw.wiphy->bands[band])
 843                                 continue;
 844
 845                         max_n = local->hw.wiphy->bands[band]->n_channels;
 846                         for (i = 0; i < max_n; i++) {
 847                                 struct ieee80211_channel *tmp_ch =
 848                                     &local->hw.wiphy->bands[band]->channels[i];
 849
 850                                 if (tmp_ch->flags & (IEEE80211_CHAN_NO_IBSS |
 851                                                      IEEE80211_CHAN_DISABLED))
 852                                         continue;
 853
 854                                 local->int_scan_req->channels[n_ch] = tmp_ch;
 855                                 n_ch++;
 856                         }
 857                 }
 858
 859                 if (WARN_ON_ONCE(n_ch == 0))
 860                         goto unlock;
 861
 862                 local->int_scan_req->n_channels = n_ch;
 863         } else {
 864                 if (WARN_ON_ONCE(chan->flags & (IEEE80211_CHAN_NO_IBSS |
 865                                                 IEEE80211_CHAN_DISABLED)))
 866                         goto unlock;
 867
 868                 local->int_scan_req->channels[0] = chan;
 869                 local->int_scan_req->n_channels = 1;
 870         }
 871
 872         local->int_scan_req->ssids = &local->scan_ssid;
 873         local->int_scan_req->n_ssids = 1;
 874         memcpy(local->int_scan_req->ssids[0].ssid, ssid, IEEE80211_MAX_SSID_LEN);
 875         local->int_scan_req->ssids[0].ssid_len = ssid_len;
 876
 877         ret = __ieee80211_start_scan(sdata, sdata->local->int_scan_req);
 878  unlock:
 879         mutex_unlock(&local->mtx);
 880         return ret;
 881 }
 882
 883 /*
 884  * Only call this function when a scan can't be queued -- under RTNL.
 885  */
 886 void ieee80211_scan_cancel(struct ieee80211_local *local)
 887 {
 888         /*
 889          * We are canceling software scan, or deferred scan that was not
 890          * yet really started (see __ieee80211_start_scan ).
 891          *
 892          * Regarding hardware scan:
 893          * - we can not call  __ieee80211_scan_completed() as when
 894          *   SCAN_HW_SCANNING bit is set this function change
 895          *   local->hw_scan_req to operate on 5G band, what race with
 896          *   driver which can use local->hw_scan_req
 897          *
 898          * - we can not cancel scan_work since driver can schedule it
 899          *   by ieee80211_scan_completed(..., true) to finish scan
 900          *
 901          * Hence we only call the cancel_hw_scan() callback, but the low-level
 902          * driver is still responsible for calling ieee80211_scan_completed()
 903          * after the scan was completed/aborted.
 904          */
 905
 906         mutex_lock(&local->mtx);
 907         if (!local->scan_req)
 908                 goto out;
 909
 910         if (test_bit(SCAN_HW_SCANNING, &local->scanning)) {
 911                 if (local->ops->cancel_hw_scan)
 912                         drv_cancel_hw_scan(local,
 913                                 rcu_dereference_protected(local->scan_sdata,
 914                                                 lockdep_is_held(&local->mtx)));
 915                 goto out;
 916         }
 917
 918         /*
 919          * If the work is currently running, it must be blocked on
 920          * the mutex, but we'll set scan_sdata = NULL and it'll
 921          * simply exit once it acquires the mutex.
 922          */
 923         cancel_delayed_work(&local->scan_work);
 924         /* and clean up */
 925         __ieee80211_scan_completed(&local->hw, true, false);
 926 out:
 927         mutex_unlock(&local->mtx);
 928 }
 929
 930 int ieee80211_request_sched_scan_start(struct ieee80211_sub_if_data *sdata,
 931                                        struct cfg80211_sched_scan_request *req)
 932 {
 933         struct ieee80211_local *local = sdata->local;
 934         struct ieee80211_sched_scan_ies sched_scan_ies = {};
 935         struct cfg80211_chan_def chandef;
 936         int ret, i, iebufsz;
 937
 938         iebufsz = 2 + IEEE80211_MAX_SSID_LEN +
 939                   local->scan_ies_len + req->ie_len;
 940
 941         mutex_lock(&local->mtx);
 942
 943         if (rcu_access_pointer(local->sched_scan_sdata)) {
 944                 ret = -EBUSY;
 945                 goto out;
 946         }
 947
 948         if (!local->ops->sched_scan_start) {
 949                 ret = -ENOTSUPP;
 950                 goto out;
 951         }
 952
 953         for (i = 0; i < IEEE80211_NUM_BANDS; i++) {
 954                 if (!local->hw.wiphy->bands[i])
 955                         continue;
 956
 957                 sched_scan_ies.ie[i] = kzalloc(iebufsz, GFP_KERNEL);
 958                 if (!sched_scan_ies.ie[i]) {
 959                         ret = -ENOMEM;
 960                         goto out_free;
 961                 }
 962
 963                 ieee80211_prepare_scan_chandef(&chandef, req->scan_width);
 964
 965                 sched_scan_ies.len[i] =
 966                         ieee80211_build_preq_ies(local, sched_scan_ies.ie[i],
 967                                                  iebufsz, req->ie, req->ie_len,
 968                                                  i, (u32) -1, &chandef);
 969         }
 970
 971         ret = drv_sched_scan_start(local, sdata, req, &sched_scan_ies);
 972         if (ret == 0)
 973                 rcu_assign_pointer(local->sched_scan_sdata, sdata);
 974
 975 out_free:
 976         while (i > 0)
 977                 kfree(sched_scan_ies.ie[--i]);
 978 out:
 979         mutex_unlock(&local->mtx);
 980         return ret;
 981 }
 982
 983 int ieee80211_request_sched_scan_stop(struct ieee80211_sub_if_data *sdata)
 984 {
 985         struct ieee80211_local *local = sdata->local;
 986         int ret = 0;
 987
 988         mutex_lock(&local->mtx);
 989
 990         if (!local->ops->sched_scan_stop) {
 991                 ret = -ENOTSUPP;
 992                 goto out;
 993         }
 994
 995         if (rcu_access_pointer(local->sched_scan_sdata))
 996                 drv_sched_scan_stop(local, sdata);
 997
 998 out:
 999         mutex_unlock(&local->mtx);
1000
1001         return ret;
1002 }
1003
1004 void ieee80211_sched_scan_results(struct ieee80211_hw *hw)
1005 {
1006         struct ieee80211_local *local = hw_to_local(hw);
1007
1008         trace_api_sched_scan_results(local);
1009
1010         cfg80211_sched_scan_results(hw->wiphy);
1011 }
1012 EXPORT_SYMBOL(ieee80211_sched_scan_results);
1013
1014 void ieee80211_sched_scan_stopped_work(struct work_struct *work)
1015 {
1016         struct ieee80211_local *local =
1017                 container_of(work, struct ieee80211_local,
1018                              sched_scan_stopped_work);
1019
1020         mutex_lock(&local->mtx);
1021
1022         if (!rcu_access_pointer(local->sched_scan_sdata)) {
1023                 mutex_unlock(&local->mtx);
1024                 return;
1025         }
1026
1027         rcu_assign_pointer(local->sched_scan_sdata, NULL);
1028
1029         mutex_unlock(&local->mtx);
1030
1031         cfg80211_sched_scan_stopped(local->hw.wiphy);
1032 }
1033
1034 void ieee80211_sched_scan_stopped(struct ieee80211_hw *hw)
1035 {
1036         struct ieee80211_local *local = hw_to_local(hw);
1037
1038         trace_api_sched_scan_stopped(local);
1039
1040         ieee80211_queue_work(&local->hw, &local->sched_scan_stopped_work);
1041 }
1042 EXPORT_SYMBOL(ieee80211_sched_scan_stopped);