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         ieee80211_configure_filter(local);
 338
 339         /* We need to set power level at maximum rate for scanning. */
 340         ieee80211_hw_config(local, 0);
 341
 342         ieee80211_queue_delayed_work(&local->hw,
 343                                      &local->scan_work, 0);
 344
 345         return 0;
 346 }
 347
 348 static bool ieee80211_can_scan(struct ieee80211_local *local,
 349                                struct ieee80211_sub_if_data *sdata)
 350 {
 351         if (!list_empty(&local->roc_list))
 352                 return false;
 353
 354         if (sdata->vif.type == NL80211_IFTYPE_STATION &&
 355             sdata->u.mgd.flags & (IEEE80211_STA_BEACON_POLL |
 356                                   IEEE80211_STA_CONNECTION_POLL))
 357                 return false;
 358
 359         return true;
 360 }
 361
 362 void ieee80211_run_deferred_scan(struct ieee80211_local *local)
 363 {
 364         lockdep_assert_held(&local->mtx);
 365
 366         if (!local->scan_req || local->scanning)
 367                 return;
 368
 369         if (!ieee80211_can_scan(local,
 370                                 rcu_dereference_protected(
 371                                         local->scan_sdata,
 372                                         lockdep_is_held(&local->mtx))))
 373                 return;
 374
 375         ieee80211_queue_delayed_work(&local->hw, &local->scan_work,
 376                                      round_jiffies_relative(0));
 377 }
 378
 379 static void ieee80211_scan_state_send_probe(struct ieee80211_local *local,
 380                                             unsigned long *next_delay)
 381 {
 382         int i;
 383         struct ieee80211_sub_if_data *sdata;
 384         enum ieee80211_band band = local->hw.conf.channel->band;
 385
 386         sdata = rcu_dereference_protected(local->scan_sdata,
 387                                           lockdep_is_held(&local->mtx));
 388
 389         for (i = 0; i < local->scan_req->n_ssids; i++)
 390                 ieee80211_send_probe_req(
 391                         sdata, NULL,
 392                         local->scan_req->ssids[i].ssid,
 393                         local->scan_req->ssids[i].ssid_len,
 394                         local->scan_req->ie, local->scan_req->ie_len,
 395                         local->scan_req->rates[band], false,
 396                         local->scan_req->no_cck ?
 397                                 IEEE80211_TX_CTL_NO_CCK_RATE : 0,
 398                         local->hw.conf.channel, true);
 399
 400         /*
 401          * After sending probe requests, wait for probe responses
 402          * on the channel.
 403          */
 404         *next_delay = IEEE80211_CHANNEL_TIME;
 405         local->next_scan_state = SCAN_DECISION;
 406 }
 407
 408 static int __ieee80211_start_scan(struct ieee80211_sub_if_data *sdata,
 409                                   struct cfg80211_scan_request *req)
 410 {
 411         struct ieee80211_local *local = sdata->local;
 412         int rc;
 413
 414         lockdep_assert_held(&local->mtx);
 415
 416         if (local->scan_req)
 417                 return -EBUSY;
 418
 419         if (!ieee80211_can_scan(local, sdata)) {
 420                 /* wait for the work to finish/time out */
 421                 local->scan_req = req;
 422                 rcu_assign_pointer(local->scan_sdata, sdata);
 423                 return 0;
 424         }
 425
 426         if (local->ops->hw_scan) {
 427                 u8 *ies;
 428
 429                 local->hw_scan_ies_bufsize = 2 + IEEE80211_MAX_SSID_LEN +
 430                                              local->scan_ies_len +
 431                                              req->ie_len;
 432                 local->hw_scan_req = kmalloc(
 433                                 sizeof(*local->hw_scan_req) +
 434                                 req->n_channels * sizeof(req->channels[0]) +
 435                                 local->hw_scan_ies_bufsize, GFP_KERNEL);
 436                 if (!local->hw_scan_req)
 437                         return -ENOMEM;
 438
 439                 local->hw_scan_req->ssids = req->ssids;
 440                 local->hw_scan_req->n_ssids = req->n_ssids;
 441                 ies = (u8 *)local->hw_scan_req +
 442                         sizeof(*local->hw_scan_req) +
 443                         req->n_channels * sizeof(req->channels[0]);
 444                 local->hw_scan_req->ie = ies;
 445                 local->hw_scan_req->flags = req->flags;
 446
 447                 local->hw_scan_band = 0;
 448
 449                 /*
 450                  * After allocating local->hw_scan_req, we must
 451                  * go through until ieee80211_prep_hw_scan(), so
 452                  * anything that might be changed here and leave
 453                  * this function early must not go after this
 454                  * allocation.
 455                  */
 456         }
 457
 458         local->scan_req = req;
 459         rcu_assign_pointer(local->scan_sdata, sdata);
 460
 461         if (local->ops->hw_scan) {
 462                 __set_bit(SCAN_HW_SCANNING, &local->scanning);
 463         } else if ((req->n_channels == 1) &&
 464                    (req->channels[0] == local->_oper_channel)) {
 465                 /*
 466                  * If we are scanning only on the operating channel
 467                  * then we do not need to stop normal activities
 468                  */
 469                 unsigned long next_delay;
 470
 471                 __set_bit(SCAN_ONCHANNEL_SCANNING, &local->scanning);
 472
 473                 ieee80211_recalc_idle(local);
 474
 475                 /* Notify driver scan is starting, keep order of operations
 476                  * same as normal software scan, in case that matters. */
 477                 drv_sw_scan_start(local);
 478
 479                 ieee80211_configure_filter(local); /* accept probe-responses */
 480
 481                 /* We need to ensure power level is at max for scanning. */
 482                 ieee80211_hw_config(local, 0);
 483
 484                 if ((req->channels[0]->flags &
 485                      IEEE80211_CHAN_PASSIVE_SCAN) ||
 486                     !local->scan_req->n_ssids) {
 487                         next_delay = IEEE80211_PASSIVE_CHANNEL_TIME;
 488                 } else {
 489                         ieee80211_scan_state_send_probe(local, &next_delay);
 490                         next_delay = IEEE80211_CHANNEL_TIME;
 491                 }
 492
 493                 /* Now, just wait a bit and we are all done! */
 494                 ieee80211_queue_delayed_work(&local->hw, &local->scan_work,
 495                                              next_delay);
 496                 return 0;
 497         } else {
 498                 /* Do normal software scan */
 499                 __set_bit(SCAN_SW_SCANNING, &local->scanning);
 500         }
 501
 502         ieee80211_recalc_idle(local);
 503
 504         if (local->ops->hw_scan) {
 505                 WARN_ON(!ieee80211_prep_hw_scan(local));
 506                 rc = drv_hw_scan(local, sdata, local->hw_scan_req);
 507         } else
 508                 rc = ieee80211_start_sw_scan(local);
 509
 510         if (rc) {
 511                 kfree(local->hw_scan_req);
 512                 local->hw_scan_req = NULL;
 513                 local->scanning = 0;
 514
 515                 ieee80211_recalc_idle(local);
 516
 517                 local->scan_req = NULL;
 518                 rcu_assign_pointer(local->scan_sdata, NULL);
 519         }
 520
 521         return rc;
 522 }
 523
 524 static unsigned long
 525 ieee80211_scan_get_channel_time(struct ieee80211_channel *chan)
 526 {
 527         /*
 528          * TODO: channel switching also consumes quite some time,
 529          * add that delay as well to get a better estimation
 530          */
 531         if (chan->flags & IEEE80211_CHAN_PASSIVE_SCAN)
 532                 return IEEE80211_PASSIVE_CHANNEL_TIME;
 533         return IEEE80211_PROBE_DELAY + IEEE80211_CHANNEL_TIME;
 534 }
 535
 536 static void ieee80211_scan_state_decision(struct ieee80211_local *local,
 537                                           unsigned long *next_delay)
 538 {
 539         bool associated = false;
 540         bool tx_empty = true;
 541         bool bad_latency;
 542         struct ieee80211_sub_if_data *sdata;
 543         struct ieee80211_channel *next_chan;
 544         enum mac80211_scan_state next_scan_state;
 545
 546         /*
 547          * check if at least one STA interface is associated,
 548          * check if at least one STA interface has pending tx frames
 549          * and grab the lowest used beacon interval
 550          */
 551         mutex_lock(&local->iflist_mtx);
 552         list_for_each_entry(sdata, &local->interfaces, list) {
 553                 if (!ieee80211_sdata_running(sdata))
 554                         continue;
 555
 556                 if (sdata->vif.type == NL80211_IFTYPE_STATION) {
 557                         if (sdata->u.mgd.associated) {
 558                                 associated = true;
 559
 560                                 if (!qdisc_all_tx_empty(sdata->dev)) {
 561                                         tx_empty = false;
 562                                         break;
 563                                 }
 564                         }
 565                 }
 566         }
 567         mutex_unlock(&local->iflist_mtx);
 568
 569         next_chan = local->scan_req->channels[local->scan_channel_idx];
 570
 571         /*
 572          * we're currently scanning a different channel, let's
 573          * see if we can scan another channel without interfering
 574          * with the current traffic situation.
 575          *
 576          * Keep good latency, do not stay off-channel more than 125 ms.
 577          */
 578
 579         bad_latency = time_after(jiffies +
 580                                  ieee80211_scan_get_channel_time(next_chan),
 581                                  local->leave_oper_channel_time + HZ / 8);
 582
 583         if (associated && !tx_empty) {
 584                 if (local->scan_req->flags & NL80211_SCAN_FLAG_LOW_PRIORITY)
 585                         next_scan_state = SCAN_ABORT;
 586                 else
 587                         next_scan_state = SCAN_SUSPEND;
 588         } else if (associated && bad_latency) {
 589                 next_scan_state = SCAN_SUSPEND;
 590         } else {
 591                 next_scan_state = SCAN_SET_CHANNEL;
 592         }
 593
 594         local->next_scan_state = next_scan_state;
 595
 596         *next_delay = 0;
 597 }
 598
 599 static void ieee80211_scan_state_set_channel(struct ieee80211_local *local,
 600                                              unsigned long *next_delay)
 601 {
 602         int skip;
 603         struct ieee80211_channel *chan;
 604
 605         skip = 0;
 606         chan = local->scan_req->channels[local->scan_channel_idx];
 607
 608         local->scan_channel = chan;
 609
 610         if (ieee80211_hw_config(local, IEEE80211_CONF_CHANGE_CHANNEL))
 611                 skip = 1;
 612
 613         /* advance state machine to next channel/band */
 614         local->scan_channel_idx++;
 615
 616         if (skip) {
 617                 /* if we skip this channel return to the decision state */
 618                 local->next_scan_state = SCAN_DECISION;
 619                 return;
 620         }
 621
 622         /*
 623          * Probe delay is used to update the NAV, cf. 11.1.3.2.2
 624          * (which unfortunately doesn't say _why_ step a) is done,
 625          * but it waits for the probe delay or until a frame is
 626          * received - and the received frame would update the NAV).
 627          * For now, we do not support waiting until a frame is
 628          * received.
 629          *
 630          * In any case, it is not necessary for a passive scan.
 631          */
 632         if (chan->flags & IEEE80211_CHAN_PASSIVE_SCAN ||
 633             !local->scan_req->n_ssids) {
 634                 *next_delay = IEEE80211_PASSIVE_CHANNEL_TIME;
 635                 local->next_scan_state = SCAN_DECISION;
 636                 return;
 637         }
 638
 639         /* active scan, send probes */
 640         *next_delay = IEEE80211_PROBE_DELAY;
 641         local->next_scan_state = SCAN_SEND_PROBE;
 642 }
 643
 644 static void ieee80211_scan_state_suspend(struct ieee80211_local *local,
 645                                          unsigned long *next_delay)
 646 {
 647         /* switch back to the operating channel */
 648         local->scan_channel = NULL;
 649         ieee80211_hw_config(local, IEEE80211_CONF_CHANGE_CHANNEL);
 650
 651         /* disable PS */
 652         ieee80211_offchannel_return(local);
 653
 654         *next_delay = HZ / 5;
 655         /* afterwards, resume scan & go to next channel */
 656         local->next_scan_state = SCAN_RESUME;
 657 }
 658
 659 static void ieee80211_scan_state_resume(struct ieee80211_local *local,
 660                                         unsigned long *next_delay)
 661 {
 662         ieee80211_offchannel_stop_vifs(local);
 663
 664         if (local->ops->flush) {
 665                 drv_flush(local, false);
 666                 *next_delay = 0;
 667         } else
 668                 *next_delay = HZ / 10;
 669
 670         /* remember when we left the operating channel */
 671         local->leave_oper_channel_time = jiffies;
 672
 673         /* advance to the next channel to be scanned */
 674         local->next_scan_state = SCAN_SET_CHANNEL;
 675 }
 676
 677 void ieee80211_scan_work(struct work_struct *work)
 678 {
 679         struct ieee80211_local *local =
 680                 container_of(work, struct ieee80211_local, scan_work.work);
 681         struct ieee80211_sub_if_data *sdata;
 682         unsigned long next_delay = 0;
 683         bool aborted, hw_scan;
 684
 685         mutex_lock(&local->mtx);
 686
 687         sdata = rcu_dereference_protected(local->scan_sdata,
 688                                           lockdep_is_held(&local->mtx));
 689
 690         /* When scanning on-channel, the first-callback means completed. */
 691         if (test_bit(SCAN_ONCHANNEL_SCANNING, &local->scanning)) {
 692                 aborted = test_and_clear_bit(SCAN_ABORTED, &local->scanning);
 693                 goto out_complete;
 694         }
 695
 696         if (test_and_clear_bit(SCAN_COMPLETED, &local->scanning)) {
 697                 aborted = test_and_clear_bit(SCAN_ABORTED, &local->scanning);
 698                 goto out_complete;
 699         }
 700
 701         if (!sdata || !local->scan_req)
 702                 goto out;
 703
 704         if (local->scan_req && !local->scanning) {
 705                 struct cfg80211_scan_request *req = local->scan_req;
 706                 int rc;
 707
 708                 local->scan_req = NULL;
 709                 rcu_assign_pointer(local->scan_sdata, NULL);
 710
 711                 rc = __ieee80211_start_scan(sdata, req);
 712                 if (rc) {
 713                         /* need to complete scan in cfg80211 */
 714                         local->scan_req = req;
 715                         aborted = true;
 716                         goto out_complete;
 717                 } else
 718                         goto out;
 719         }
 720
 721         /*
 722          * Avoid re-scheduling when the sdata is going away.
 723          */
 724         if (!ieee80211_sdata_running(sdata)) {
 725                 aborted = true;
 726                 goto out_complete;
 727         }
 728
 729         /*
 730          * as long as no delay is required advance immediately
 731          * without scheduling a new work
 732          */
 733         do {
 734                 if (!ieee80211_sdata_running(sdata)) {
 735                         aborted = true;
 736                         goto out_complete;
 737                 }
 738
 739                 switch (local->next_scan_state) {
 740                 case SCAN_DECISION:
 741                         /* if no more bands/channels left, complete scan */
 742                         if (local->scan_channel_idx >= local->scan_req->n_channels) {
 743                                 aborted = false;
 744                                 goto out_complete;
 745                         }
 746                         ieee80211_scan_state_decision(local, &next_delay);
 747                         break;
 748                 case SCAN_SET_CHANNEL:
 749                         ieee80211_scan_state_set_channel(local, &next_delay);
 750                         break;
 751                 case SCAN_SEND_PROBE:
 752                         ieee80211_scan_state_send_probe(local, &next_delay);
 753                         break;
 754                 case SCAN_SUSPEND:
 755                         ieee80211_scan_state_suspend(local, &next_delay);
 756                         break;
 757                 case SCAN_RESUME:
 758                         ieee80211_scan_state_resume(local, &next_delay);
 759                         break;
 760                 case SCAN_ABORT:
 761                         aborted = true;
 762                         goto out_complete;
 763                 }
 764         } while (next_delay == 0);
 765
 766         ieee80211_queue_delayed_work(&local->hw, &local->scan_work, next_delay);
 767         goto out;
 768
 769 out_complete:
 770         hw_scan = test_bit(SCAN_HW_SCANNING, &local->scanning);
 771         __ieee80211_scan_completed(&local->hw, aborted, hw_scan);
 772 out:
 773         mutex_unlock(&local->mtx);
 774 }
 775
 776 int ieee80211_request_scan(struct ieee80211_sub_if_data *sdata,
 777                            struct cfg80211_scan_request *req)
 778 {
 779         int res;
 780
 781         mutex_lock(&sdata->local->mtx);
 782         res = __ieee80211_start_scan(sdata, req);
 783         mutex_unlock(&sdata->local->mtx);
 784
 785         return res;
 786 }
 787
 788 int ieee80211_request_ibss_scan(struct ieee80211_sub_if_data *sdata,
 789                                 const u8 *ssid, u8 ssid_len,
 790                                 struct ieee80211_channel *chan)
 791 {
 792         struct ieee80211_local *local = sdata->local;
 793         int ret = -EBUSY;
 794         enum ieee80211_band band;
 795
 796         mutex_lock(&local->mtx);
 797
 798         /* busy scanning */
 799         if (local->scan_req)
 800                 goto unlock;
 801
 802         /* fill internal scan request */
 803         if (!chan) {
 804                 int i, max_n;
 805                 int n_ch = 0;
 806
 807                 for (band = 0; band < IEEE80211_NUM_BANDS; band++) {
 808                         if (!local->hw.wiphy->bands[band])
 809                                 continue;
 810
 811                         max_n = local->hw.wiphy->bands[band]->n_channels;
 812                         for (i = 0; i < max_n; i++) {
 813                                 struct ieee80211_channel *tmp_ch =
 814                                     &local->hw.wiphy->bands[band]->channels[i];
 815
 816                                 if (tmp_ch->flags & (IEEE80211_CHAN_NO_IBSS |
 817                                                      IEEE80211_CHAN_DISABLED))
 818                                         continue;
 819
 820                                 local->int_scan_req->channels[n_ch] = tmp_ch;
 821                                 n_ch++;
 822                         }
 823                 }
 824
 825                 if (WARN_ON_ONCE(n_ch == 0))
 826                         goto unlock;
 827
 828                 local->int_scan_req->n_channels = n_ch;
 829         } else {
 830                 if (WARN_ON_ONCE(chan->flags & (IEEE80211_CHAN_NO_IBSS |
 831                                                 IEEE80211_CHAN_DISABLED)))
 832                         goto unlock;
 833
 834                 local->int_scan_req->channels[0] = chan;
 835                 local->int_scan_req->n_channels = 1;
 836         }
 837
 838         local->int_scan_req->ssids = &local->scan_ssid;
 839         local->int_scan_req->n_ssids = 1;
 840         memcpy(local->int_scan_req->ssids[0].ssid, ssid, IEEE80211_MAX_SSID_LEN);
 841         local->int_scan_req->ssids[0].ssid_len = ssid_len;
 842
 843         ret = __ieee80211_start_scan(sdata, sdata->local->int_scan_req);
 844  unlock:
 845         mutex_unlock(&local->mtx);
 846         return ret;
 847 }
 848
 849 /*
 850  * Only call this function when a scan can't be queued -- under RTNL.
 851  */
 852 void ieee80211_scan_cancel(struct ieee80211_local *local)
 853 {
 854         /*
 855          * We are canceling software scan, or deferred scan that was not
 856          * yet really started (see __ieee80211_start_scan ).
 857          *
 858          * Regarding hardware scan:
 859          * - we can not call  __ieee80211_scan_completed() as when
 860          *   SCAN_HW_SCANNING bit is set this function change
 861          *   local->hw_scan_req to operate on 5G band, what race with
 862          *   driver which can use local->hw_scan_req
 863          *
 864          * - we can not cancel scan_work since driver can schedule it
 865          *   by ieee80211_scan_completed(..., true) to finish scan
 866          *
 867          * Hence we only call the cancel_hw_scan() callback, but the low-level
 868          * driver is still responsible for calling ieee80211_scan_completed()
 869          * after the scan was completed/aborted.
 870          */
 871
 872         mutex_lock(&local->mtx);
 873         if (!local->scan_req)
 874                 goto out;
 875
 876         if (test_bit(SCAN_HW_SCANNING, &local->scanning)) {
 877                 if (local->ops->cancel_hw_scan)
 878                         drv_cancel_hw_scan(local,
 879                                 rcu_dereference_protected(local->scan_sdata,
 880                                                 lockdep_is_held(&local->mtx)));
 881                 goto out;
 882         }
 883
 884         /*
 885          * If the work is currently running, it must be blocked on
 886          * the mutex, but we'll set scan_sdata = NULL and it'll
 887          * simply exit once it acquires the mutex.
 888          */
 889         cancel_delayed_work(&local->scan_work);
 890         /* and clean up */
 891         __ieee80211_scan_completed(&local->hw, true, false);
 892 out:
 893         mutex_unlock(&local->mtx);
 894 }
 895
 896 int ieee80211_request_sched_scan_start(struct ieee80211_sub_if_data *sdata,
 897                                        struct cfg80211_sched_scan_request *req)
 898 {
 899         struct ieee80211_local *local = sdata->local;
 900         struct ieee80211_sched_scan_ies sched_scan_ies = {};
 901         int ret, i, iebufsz;
 902
 903         iebufsz = 2 + IEEE80211_MAX_SSID_LEN +
 904                   local->scan_ies_len + req->ie_len;
 905
 906         mutex_lock(&local->mtx);
 907
 908         if (rcu_access_pointer(local->sched_scan_sdata)) {
 909                 ret = -EBUSY;
 910                 goto out;
 911         }
 912
 913         if (!local->ops->sched_scan_start) {
 914                 ret = -ENOTSUPP;
 915                 goto out;
 916         }
 917
 918         for (i = 0; i < IEEE80211_NUM_BANDS; i++) {
 919                 if (!local->hw.wiphy->bands[i])
 920                         continue;
 921
 922                 sched_scan_ies.ie[i] = kzalloc(iebufsz, GFP_KERNEL);
 923                 if (!sched_scan_ies.ie[i]) {
 924                         ret = -ENOMEM;
 925                         goto out_free;
 926                 }
 927
 928                 sched_scan_ies.len[i] =
 929                         ieee80211_build_preq_ies(local, sched_scan_ies.ie[i],
 930                                                  iebufsz, req->ie, req->ie_len,
 931                                                  i, (u32) -1, 0);
 932         }
 933
 934         ret = drv_sched_scan_start(local, sdata, req, &sched_scan_ies);
 935         if (ret == 0)
 936                 rcu_assign_pointer(local->sched_scan_sdata, sdata);
 937
 938 out_free:
 939         while (i > 0)
 940                 kfree(sched_scan_ies.ie[--i]);
 941 out:
 942         mutex_unlock(&local->mtx);
 943         return ret;
 944 }
 945
 946 int ieee80211_request_sched_scan_stop(struct ieee80211_sub_if_data *sdata)
 947 {
 948         struct ieee80211_local *local = sdata->local;
 949         int ret = 0;
 950
 951         mutex_lock(&local->mtx);
 952
 953         if (!local->ops->sched_scan_stop) {
 954                 ret = -ENOTSUPP;
 955                 goto out;
 956         }
 957
 958         if (rcu_access_pointer(local->sched_scan_sdata))
 959                 drv_sched_scan_stop(local, sdata);
 960
 961 out:
 962         mutex_unlock(&local->mtx);
 963
 964         return ret;
 965 }
 966
 967 void ieee80211_sched_scan_results(struct ieee80211_hw *hw)
 968 {
 969         struct ieee80211_local *local = hw_to_local(hw);
 970
 971         trace_api_sched_scan_results(local);
 972
 973         cfg80211_sched_scan_results(hw->wiphy);
 974 }
 975 EXPORT_SYMBOL(ieee80211_sched_scan_results);
 976
 977 void ieee80211_sched_scan_stopped_work(struct work_struct *work)
 978 {
 979         struct ieee80211_local *local =
 980                 container_of(work, struct ieee80211_local,
 981                              sched_scan_stopped_work);
 982
 983         mutex_lock(&local->mtx);
 984
 985         if (!rcu_access_pointer(local->sched_scan_sdata)) {
 986                 mutex_unlock(&local->mtx);
 987                 return;
 988         }
 989
 990         rcu_assign_pointer(local->sched_scan_sdata, NULL);
 991
 992         mutex_unlock(&local->mtx);
 993
 994         cfg80211_sched_scan_stopped(local->hw.wiphy);
 995 }
 996
 997 void ieee80211_sched_scan_stopped(struct ieee80211_hw *hw)
 998 {
 999         struct ieee80211_local *local = hw_to_local(hw);
1000
1001         trace_api_sched_scan_stopped(local);
1002
1003         ieee80211_queue_work(&local->hw, &local->sched_scan_stopped_work);
1004 }
1005 EXPORT_SYMBOL(ieee80211_sched_scan_stopped);