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