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         enum nl80211_bss_scan_width scan_width;
  70         s32 signal = 0;
  71
  72         if (local->hw.flags & IEEE80211_HW_SIGNAL_DBM)
  73                 signal = rx_status->signal * 100;
  74         else if (local->hw.flags & IEEE80211_HW_SIGNAL_UNSPEC)
  75                 signal = (rx_status->signal * 100) / local->hw.max_signal;
  76
  77         scan_width = NL80211_BSS_CHAN_WIDTH_20;
  78         if (rx_status->flag & RX_FLAG_5MHZ)
  79                 scan_width = NL80211_BSS_CHAN_WIDTH_5;
  80         if (rx_status->flag & RX_FLAG_10MHZ)
  81                 scan_width = NL80211_BSS_CHAN_WIDTH_10;
  82
  83         cbss = cfg80211_inform_bss_width_frame(local->hw.wiphy, channel,
  84                                                scan_width, mgmt, len, signal,
  85                                                GFP_ATOMIC);
  86         if (!cbss)
  87                 return NULL;
  88
  89         bss = (void *)cbss->priv;
  90
  91         if (beacon)
  92                 bss->device_ts_beacon = rx_status->device_timestamp;
  93         else
  94                 bss->device_ts_presp = rx_status->device_timestamp;
  95
  96         if (elems->parse_error) {
  97                 if (beacon)
  98                         bss->corrupt_data |= IEEE80211_BSS_CORRUPT_BEACON;
  99                 else
 100                         bss->corrupt_data |= IEEE80211_BSS_CORRUPT_PROBE_RESP;
 101         } else {
 102                 if (beacon)
 103                         bss->corrupt_data &= ~IEEE80211_BSS_CORRUPT_BEACON;
 104                 else
 105                         bss->corrupt_data &= ~IEEE80211_BSS_CORRUPT_PROBE_RESP;
 106         }
 107
 108         /* save the ERP value so that it is available at association time */
 109         if (elems->erp_info && (!elems->parse_error ||
 110                                 !(bss->valid_data & IEEE80211_BSS_VALID_ERP))) {
 111                 bss->erp_value = elems->erp_info[0];
 112                 bss->has_erp_value = true;
 113                 if (!elems->parse_error)
 114                         bss->valid_data |= IEEE80211_BSS_VALID_ERP;
 115         }
 116
 117         /* replace old supported rates if we get new values */
 118         if (!elems->parse_error ||
 119             !(bss->valid_data & IEEE80211_BSS_VALID_RATES)) {
 120                 srlen = 0;
 121                 if (elems->supp_rates) {
 122                         clen = IEEE80211_MAX_SUPP_RATES;
 123                         if (clen > elems->supp_rates_len)
 124                                 clen = elems->supp_rates_len;
 125                         memcpy(bss->supp_rates, elems->supp_rates, clen);
 126                         srlen += clen;
 127                 }
 128                 if (elems->ext_supp_rates) {
 129                         clen = IEEE80211_MAX_SUPP_RATES - srlen;
 130                         if (clen > elems->ext_supp_rates_len)
 131                                 clen = elems->ext_supp_rates_len;
 132                         memcpy(bss->supp_rates + srlen, elems->ext_supp_rates,
 133                                clen);
 134                         srlen += clen;
 135                 }
 136                 if (srlen) {
 137                         bss->supp_rates_len = srlen;
 138                         if (!elems->parse_error)
 139                                 bss->valid_data |= IEEE80211_BSS_VALID_RATES;
 140                 }
 141         }
 142
 143         if (!elems->parse_error ||
 144             !(bss->valid_data & IEEE80211_BSS_VALID_WMM)) {
 145                 bss->wmm_used = elems->wmm_param || elems->wmm_info;
 146                 bss->uapsd_supported = is_uapsd_supported(elems);
 147                 if (!elems->parse_error)
 148                         bss->valid_data |= IEEE80211_BSS_VALID_WMM;
 149         }
 150
 151         if (beacon) {
 152                 struct ieee80211_supported_band *sband =
 153                         local->hw.wiphy->bands[rx_status->band];
 154                 if (!(rx_status->flag & RX_FLAG_HT) &&
 155                     !(rx_status->flag & RX_FLAG_VHT))
 156                         bss->beacon_rate =
 157                                 &sband->bitrates[rx_status->rate_idx];
 158         }
 159
 160         return bss;
 161 }
 162
 163 void ieee80211_scan_rx(struct ieee80211_local *local, struct sk_buff *skb)
 164 {
 165         struct ieee80211_rx_status *rx_status = IEEE80211_SKB_RXCB(skb);
 166         struct ieee80211_sub_if_data *sdata1, *sdata2;
 167         struct ieee80211_mgmt *mgmt = (void *)skb->data;
 168         struct ieee80211_bss *bss;
 169         u8 *elements;
 170         struct ieee80211_channel *channel;
 171         size_t baselen;
 172         struct ieee802_11_elems elems;
 173
 174         if (skb->len < 24 ||
 175             (!ieee80211_is_probe_resp(mgmt->frame_control) &&
 176              !ieee80211_is_beacon(mgmt->frame_control)))
 177                 return;
 178
 179         sdata1 = rcu_dereference(local->scan_sdata);
 180         sdata2 = rcu_dereference(local->sched_scan_sdata);
 181
 182         if (likely(!sdata1 && !sdata2))
 183                 return;
 184
 185         if (ieee80211_is_probe_resp(mgmt->frame_control)) {
 186                 /* ignore ProbeResp to foreign address */
 187                 if ((!sdata1 || !ether_addr_equal(mgmt->da, sdata1->vif.addr)) &&
 188                     (!sdata2 || !ether_addr_equal(mgmt->da, sdata2->vif.addr)))
 189                         return;
 190
 191                 elements = mgmt->u.probe_resp.variable;
 192                 baselen = offsetof(struct ieee80211_mgmt, u.probe_resp.variable);
 193         } else {
 194                 baselen = offsetof(struct ieee80211_mgmt, u.beacon.variable);
 195                 elements = mgmt->u.beacon.variable;
 196         }
 197
 198         if (baselen > skb->len)
 199                 return;
 200
 201         ieee802_11_parse_elems(elements, skb->len - baselen, false, &elems);
 202
 203         channel = ieee80211_get_channel(local->hw.wiphy, rx_status->freq);
 204
 205         if (!channel || channel->flags & IEEE80211_CHAN_DISABLED)
 206                 return;
 207
 208         bss = ieee80211_bss_info_update(local, rx_status,
 209                                         mgmt, skb->len, &elems,
 210                                         channel);
 211         if (bss)
 212                 ieee80211_rx_bss_put(local, bss);
 213 }
 214
 215 static void
 216 ieee80211_prepare_scan_chandef(struct cfg80211_chan_def *chandef,
 217                                enum nl80211_bss_scan_width scan_width)
 218 {
 219         memset(chandef, 0, sizeof(*chandef));
 220         switch (scan_width) {
 221         case NL80211_BSS_CHAN_WIDTH_5:
 222                 chandef->width = NL80211_CHAN_WIDTH_5;
 223                 break;
 224         case NL80211_BSS_CHAN_WIDTH_10:
 225                 chandef->width = NL80211_CHAN_WIDTH_10;
 226                 break;
 227         default:
 228                 chandef->width = NL80211_CHAN_WIDTH_20_NOHT;
 229                 break;
 230         }
 231 }
 232
 233 /* return false if no more work */
 234 static bool ieee80211_prep_hw_scan(struct ieee80211_local *local)
 235 {
 236         struct cfg80211_scan_request *req = local->scan_req;
 237         struct cfg80211_chan_def chandef;
 238         enum ieee80211_band band;
 239         int i, ielen, n_chans;
 240
 241         do {
 242                 if (local->hw_scan_band == IEEE80211_NUM_BANDS)
 243                         return false;
 244
 245                 band = local->hw_scan_band;
 246                 n_chans = 0;
 247                 for (i = 0; i < req->n_channels; i++) {
 248                         if (req->channels[i]->band == band) {
 249                                 local->hw_scan_req->channels[n_chans] =
 250                                                         req->channels[i];
 251                                 n_chans++;
 252                         }
 253                 }
 254
 255                 local->hw_scan_band++;
 256         } while (!n_chans);
 257
 258         local->hw_scan_req->n_channels = n_chans;
 259         ieee80211_prepare_scan_chandef(&chandef, req->scan_width);
 260
 261         ielen = ieee80211_build_preq_ies(local, (u8 *)local->hw_scan_req->ie,
 262                                          local->hw_scan_ies_bufsize,
 263                                          req->ie, req->ie_len, band,
 264                                          req->rates[band], &chandef);
 265         local->hw_scan_req->ie_len = ielen;
 266         local->hw_scan_req->no_cck = req->no_cck;
 267
 268         return true;
 269 }
 270
 271 static void __ieee80211_scan_completed(struct ieee80211_hw *hw, bool aborted,
 272                                        bool was_hw_scan)
 273 {
 274         struct ieee80211_local *local = hw_to_local(hw);
 275
 276         lockdep_assert_held(&local->mtx);
 277
 278         /*
 279          * It's ok to abort a not-yet-running scan (that
 280          * we have one at all will be verified by checking
 281          * local->scan_req next), but not to complete it
 282          * successfully.
 283          */
 284         if (WARN_ON(!local->scanning && !aborted))
 285                 aborted = true;
 286
 287         if (WARN_ON(!local->scan_req))
 288                 return;
 289
 290         if (was_hw_scan && !aborted && ieee80211_prep_hw_scan(local)) {
 291                 int rc;
 292
 293                 rc = drv_hw_scan(local,
 294                         rcu_dereference_protected(local->scan_sdata,
 295                                                   lockdep_is_held(&local->mtx)),
 296                         local->hw_scan_req);
 297
 298                 if (rc == 0)
 299                         return;
 300         }
 301
 302         kfree(local->hw_scan_req);
 303         local->hw_scan_req = NULL;
 304
 305         if (local->scan_req != local->int_scan_req)
 306                 cfg80211_scan_done(local->scan_req, aborted);
 307         local->scan_req = NULL;
 308         rcu_assign_pointer(local->scan_sdata, NULL);
 309
 310         local->scanning = 0;
 311         local->scan_chandef.chan = NULL;
 312
 313         /* Set power back to normal operating levels. */
 314         ieee80211_hw_config(local, 0);
 315
 316         if (!was_hw_scan) {
 317                 ieee80211_configure_filter(local);
 318                 drv_sw_scan_complete(local);
 319                 ieee80211_offchannel_return(local);
 320         }
 321
 322         ieee80211_recalc_idle(local);
 323
 324         ieee80211_mlme_notify_scan_completed(local);
 325         ieee80211_ibss_notify_scan_completed(local);
 326         ieee80211_mesh_notify_scan_completed(local);
 327         ieee80211_start_next_roc(local);
 328 }
 329
 330 void ieee80211_scan_completed(struct ieee80211_hw *hw, bool aborted)
 331 {
 332         struct ieee80211_local *local = hw_to_local(hw);
 333
 334         trace_api_scan_completed(local, aborted);
 335
 336         set_bit(SCAN_COMPLETED, &local->scanning);
 337         if (aborted)
 338                 set_bit(SCAN_ABORTED, &local->scanning);
 339         ieee80211_queue_delayed_work(&local->hw, &local->scan_work, 0);
 340 }
 341 EXPORT_SYMBOL(ieee80211_scan_completed);
 342
 343 static int ieee80211_start_sw_scan(struct ieee80211_local *local)
 344 {
 345         /* Software scan is not supported in multi-channel cases */
 346         if (local->use_chanctx)
 347                 return -EOPNOTSUPP;
 348
 349         /*
 350          * Hardware/driver doesn't support hw_scan, so use software
 351          * scanning instead. First send a nullfunc frame with power save
 352          * bit on so that AP will buffer the frames for us while we are not
 353          * listening, then send probe requests to each channel and wait for
 354          * the responses. After all channels are scanned, tune back to the
 355          * original channel and send a nullfunc frame with power save bit
 356          * off to trigger the AP to send us all the buffered frames.
 357          *
 358          * Note that while local->sw_scanning is true everything else but
 359          * nullfunc frames and probe requests will be dropped in
 360          * ieee80211_tx_h_check_assoc().
 361          */
 362         drv_sw_scan_start(local);
 363
 364         local->leave_oper_channel_time = jiffies;
 365         local->next_scan_state = SCAN_DECISION;
 366         local->scan_channel_idx = 0;
 367
 368         ieee80211_offchannel_stop_vifs(local);
 369
 370         /* ensure nullfunc is transmitted before leaving operating channel */
 371         ieee80211_flush_queues(local, NULL);
 372
 373         ieee80211_configure_filter(local);
 374
 375         /* We need to set power level at maximum rate for scanning. */
 376         ieee80211_hw_config(local, 0);
 377
 378         ieee80211_queue_delayed_work(&local->hw,
 379                                      &local->scan_work, 0);
 380
 381         return 0;
 382 }
 383
 384 static bool ieee80211_can_scan(struct ieee80211_local *local,
 385                                struct ieee80211_sub_if_data *sdata)
 386 {
 387         if (local->radar_detect_enabled)
 388                 return false;
 389
 390         if (!list_empty(&local->roc_list))
 391                 return false;
 392
 393         if (sdata->vif.type == NL80211_IFTYPE_STATION &&
 394             sdata->u.mgd.flags & (IEEE80211_STA_BEACON_POLL |
 395                                   IEEE80211_STA_CONNECTION_POLL))
 396                 return false;
 397
 398         return true;
 399 }
 400
 401 void ieee80211_run_deferred_scan(struct ieee80211_local *local)
 402 {
 403         lockdep_assert_held(&local->mtx);
 404
 405         if (!local->scan_req || local->scanning)
 406                 return;
 407
 408         if (!ieee80211_can_scan(local,
 409                                 rcu_dereference_protected(
 410                                         local->scan_sdata,
 411                                         lockdep_is_held(&local->mtx))))
 412                 return;
 413
 414         ieee80211_queue_delayed_work(&local->hw, &local->scan_work,
 415                                      round_jiffies_relative(0));
 416 }
 417
 418 static void ieee80211_scan_state_send_probe(struct ieee80211_local *local,
 419                                             unsigned long *next_delay)
 420 {
 421         int i;
 422         struct ieee80211_sub_if_data *sdata;
 423         enum ieee80211_band band = local->hw.conf.chandef.chan->band;
 424         u32 tx_flags;
 425
 426         tx_flags = IEEE80211_TX_INTFL_OFFCHAN_TX_OK;
 427         if (local->scan_req->no_cck)
 428                 tx_flags |= IEEE80211_TX_CTL_NO_CCK_RATE;
 429
 430         sdata = rcu_dereference_protected(local->scan_sdata,
 431                                           lockdep_is_held(&local->mtx));
 432
 433         for (i = 0; i < local->scan_req->n_ssids; i++)
 434                 ieee80211_send_probe_req(
 435                         sdata, NULL,
 436                         local->scan_req->ssids[i].ssid,
 437                         local->scan_req->ssids[i].ssid_len,
 438                         local->scan_req->ie, local->scan_req->ie_len,
 439                         local->scan_req->rates[band], false,
 440                         tx_flags, local->hw.conf.chandef.chan, true);
 441
 442         /*
 443          * After sending probe requests, wait for probe responses
 444          * on the channel.
 445          */
 446         *next_delay = IEEE80211_CHANNEL_TIME;
 447         local->next_scan_state = SCAN_DECISION;
 448 }
 449
 450 static int __ieee80211_start_scan(struct ieee80211_sub_if_data *sdata,
 451                                   struct cfg80211_scan_request *req)
 452 {
 453         struct ieee80211_local *local = sdata->local;
 454         int rc;
 455
 456         lockdep_assert_held(&local->mtx);
 457
 458         if (local->scan_req)
 459                 return -EBUSY;
 460
 461         if (!ieee80211_can_scan(local, sdata)) {
 462                 /* wait for the work to finish/time out */
 463                 local->scan_req = req;
 464                 rcu_assign_pointer(local->scan_sdata, sdata);
 465                 return 0;
 466         }
 467
 468         if (local->ops->hw_scan) {
 469                 u8 *ies;
 470
 471                 local->hw_scan_ies_bufsize = 2 + IEEE80211_MAX_SSID_LEN +
 472                                              local->scan_ies_len +
 473                                              req->ie_len;
 474                 local->hw_scan_req = kmalloc(
 475                                 sizeof(*local->hw_scan_req) +
 476                                 req->n_channels * sizeof(req->channels[0]) +
 477                                 local->hw_scan_ies_bufsize, GFP_KERNEL);
 478                 if (!local->hw_scan_req)
 479                         return -ENOMEM;
 480
 481                 local->hw_scan_req->ssids = req->ssids;
 482                 local->hw_scan_req->n_ssids = req->n_ssids;
 483                 ies = (u8 *)local->hw_scan_req +
 484                         sizeof(*local->hw_scan_req) +
 485                         req->n_channels * sizeof(req->channels[0]);
 486                 local->hw_scan_req->ie = ies;
 487                 local->hw_scan_req->flags = req->flags;
 488
 489                 local->hw_scan_band = 0;
 490
 491                 /*
 492                  * After allocating local->hw_scan_req, we must
 493                  * go through until ieee80211_prep_hw_scan(), so
 494                  * anything that might be changed here and leave
 495                  * this function early must not go after this
 496                  * allocation.
 497                  */
 498         }
 499
 500         local->scan_req = req;
 501         rcu_assign_pointer(local->scan_sdata, sdata);
 502
 503         if (local->ops->hw_scan) {
 504                 __set_bit(SCAN_HW_SCANNING, &local->scanning);
 505         } else if ((req->n_channels == 1) &&
 506                    (req->channels[0] == local->_oper_chandef.chan)) {
 507                 /*
 508                  * If we are scanning only on the operating channel
 509                  * then we do not need to stop normal activities
 510                  */
 511                 unsigned long next_delay;
 512
 513                 __set_bit(SCAN_ONCHANNEL_SCANNING, &local->scanning);
 514
 515                 ieee80211_recalc_idle(local);
 516
 517                 /* Notify driver scan is starting, keep order of operations
 518                  * same as normal software scan, in case that matters. */
 519                 drv_sw_scan_start(local);
 520
 521                 ieee80211_configure_filter(local); /* accept probe-responses */
 522
 523                 /* We need to ensure power level is at max for scanning. */
 524                 ieee80211_hw_config(local, 0);
 525
 526                 if ((req->channels[0]->flags &
 527                      IEEE80211_CHAN_PASSIVE_SCAN) ||
 528                     !local->scan_req->n_ssids) {
 529                         next_delay = IEEE80211_PASSIVE_CHANNEL_TIME;
 530                 } else {
 531                         ieee80211_scan_state_send_probe(local, &next_delay);
 532                         next_delay = IEEE80211_CHANNEL_TIME;
 533                 }
 534
 535                 /* Now, just wait a bit and we are all done! */
 536                 ieee80211_queue_delayed_work(&local->hw, &local->scan_work,
 537                                              next_delay);
 538                 return 0;
 539         } else {
 540                 /* Do normal software scan */
 541                 __set_bit(SCAN_SW_SCANNING, &local->scanning);
 542         }
 543
 544         ieee80211_recalc_idle(local);
 545
 546         if (local->ops->hw_scan) {
 547                 WARN_ON(!ieee80211_prep_hw_scan(local));
 548                 rc = drv_hw_scan(local, sdata, local->hw_scan_req);
 549         } else
 550                 rc = ieee80211_start_sw_scan(local);
 551
 552         if (rc) {
 553                 kfree(local->hw_scan_req);
 554                 local->hw_scan_req = NULL;
 555                 local->scanning = 0;
 556
 557                 ieee80211_recalc_idle(local);
 558
 559                 local->scan_req = NULL;
 560                 rcu_assign_pointer(local->scan_sdata, NULL);
 561         }
 562
 563         return rc;
 564 }
 565
 566 static unsigned long
 567 ieee80211_scan_get_channel_time(struct ieee80211_channel *chan)
 568 {
 569         /*
 570          * TODO: channel switching also consumes quite some time,
 571          * add that delay as well to get a better estimation
 572          */
 573         if (chan->flags & IEEE80211_CHAN_PASSIVE_SCAN)
 574                 return IEEE80211_PASSIVE_CHANNEL_TIME;
 575         return IEEE80211_PROBE_DELAY + IEEE80211_CHANNEL_TIME;
 576 }
 577
 578 static void ieee80211_scan_state_decision(struct ieee80211_local *local,
 579                                           unsigned long *next_delay)
 580 {
 581         bool associated = false;
 582         bool tx_empty = true;
 583         bool bad_latency;
 584         struct ieee80211_sub_if_data *sdata;
 585         struct ieee80211_channel *next_chan;
 586         enum mac80211_scan_state next_scan_state;
 587
 588         /*
 589          * check if at least one STA interface is associated,
 590          * check if at least one STA interface has pending tx frames
 591          * and grab the lowest used beacon interval
 592          */
 593         mutex_lock(&local->iflist_mtx);
 594         list_for_each_entry(sdata, &local->interfaces, list) {
 595                 if (!ieee80211_sdata_running(sdata))
 596                         continue;
 597
 598                 if (sdata->vif.type == NL80211_IFTYPE_STATION) {
 599                         if (sdata->u.mgd.associated) {
 600                                 associated = true;
 601
 602                                 if (!qdisc_all_tx_empty(sdata->dev)) {
 603                                         tx_empty = false;
 604                                         break;
 605                                 }
 606                         }
 607                 }
 608         }
 609         mutex_unlock(&local->iflist_mtx);
 610
 611         next_chan = local->scan_req->channels[local->scan_channel_idx];
 612
 613         /*
 614          * we're currently scanning a different channel, let's
 615          * see if we can scan another channel without interfering
 616          * with the current traffic situation.
 617          *
 618          * Keep good latency, do not stay off-channel more than 125 ms.
 619          */
 620
 621         bad_latency = time_after(jiffies +
 622                                  ieee80211_scan_get_channel_time(next_chan),
 623                                  local->leave_oper_channel_time + HZ / 8);
 624
 625         if (associated && !tx_empty) {
 626                 if (local->scan_req->flags & NL80211_SCAN_FLAG_LOW_PRIORITY)
 627                         next_scan_state = SCAN_ABORT;
 628                 else
 629                         next_scan_state = SCAN_SUSPEND;
 630         } else if (associated && bad_latency) {
 631                 next_scan_state = SCAN_SUSPEND;
 632         } else {
 633                 next_scan_state = SCAN_SET_CHANNEL;
 634         }
 635
 636         local->next_scan_state = next_scan_state;
 637
 638         *next_delay = 0;
 639 }
 640
 641 static void ieee80211_scan_state_set_channel(struct ieee80211_local *local,
 642                                              unsigned long *next_delay)
 643 {
 644         int skip;
 645         struct ieee80211_channel *chan;
 646         enum nl80211_bss_scan_width oper_scan_width;
 647
 648         skip = 0;
 649         chan = local->scan_req->channels[local->scan_channel_idx];
 650
 651         local->scan_chandef.chan = chan;
 652         local->scan_chandef.center_freq1 = chan->center_freq;
 653         local->scan_chandef.center_freq2 = 0;
 654         switch (local->scan_req->scan_width) {
 655         case NL80211_BSS_CHAN_WIDTH_5:
 656                 local->scan_chandef.width = NL80211_CHAN_WIDTH_5;
 657                 break;
 658         case NL80211_BSS_CHAN_WIDTH_10:
 659                 local->scan_chandef.width = NL80211_CHAN_WIDTH_10;
 660                 break;
 661         case NL80211_BSS_CHAN_WIDTH_20:
 662                 /* If scanning on oper channel, use whatever channel-type
 663                  * is currently in use.
 664                  */
 665                 oper_scan_width = cfg80211_chandef_to_scan_width(
 666                                         &local->_oper_chandef);
 667                 if (chan == local->_oper_chandef.chan &&
 668                     oper_scan_width == local->scan_req->scan_width)
 669                         local->scan_chandef = local->_oper_chandef;
 670                 else
 671                         local->scan_chandef.width = NL80211_CHAN_WIDTH_20_NOHT;
 672                 break;
 673         }
 674
 675         if (ieee80211_hw_config(local, IEEE80211_CONF_CHANGE_CHANNEL))
 676                 skip = 1;
 677
 678         /* advance state machine to next channel/band */
 679         local->scan_channel_idx++;
 680
 681         if (skip) {
 682                 /* if we skip this channel return to the decision state */
 683                 local->next_scan_state = SCAN_DECISION;
 684                 return;
 685         }
 686
 687         /*
 688          * Probe delay is used to update the NAV, cf. 11.1.3.2.2
 689          * (which unfortunately doesn't say _why_ step a) is done,
 690          * but it waits for the probe delay or until a frame is
 691          * received - and the received frame would update the NAV).
 692          * For now, we do not support waiting until a frame is
 693          * received.
 694          *
 695          * In any case, it is not necessary for a passive scan.
 696          */
 697         if (chan->flags & IEEE80211_CHAN_PASSIVE_SCAN ||
 698             !local->scan_req->n_ssids) {
 699                 *next_delay = IEEE80211_PASSIVE_CHANNEL_TIME;
 700                 local->next_scan_state = SCAN_DECISION;
 701                 return;
 702         }
 703
 704         /* active scan, send probes */
 705         *next_delay = IEEE80211_PROBE_DELAY;
 706         local->next_scan_state = SCAN_SEND_PROBE;
 707 }
 708
 709 static void ieee80211_scan_state_suspend(struct ieee80211_local *local,
 710                                          unsigned long *next_delay)
 711 {
 712         /* switch back to the operating channel */
 713         local->scan_chandef.chan = NULL;
 714         ieee80211_hw_config(local, IEEE80211_CONF_CHANGE_CHANNEL);
 715
 716         /* disable PS */
 717         ieee80211_offchannel_return(local);
 718
 719         *next_delay = HZ / 5;
 720         /* afterwards, resume scan & go to next channel */
 721         local->next_scan_state = SCAN_RESUME;
 722 }
 723
 724 static void ieee80211_scan_state_resume(struct ieee80211_local *local,
 725                                         unsigned long *next_delay)
 726 {
 727         ieee80211_offchannel_stop_vifs(local);
 728
 729         if (local->ops->flush) {
 730                 ieee80211_flush_queues(local, NULL);
 731                 *next_delay = 0;
 732         } else
 733                 *next_delay = HZ / 10;
 734
 735         /* remember when we left the operating channel */
 736         local->leave_oper_channel_time = jiffies;
 737
 738         /* advance to the next channel to be scanned */
 739         local->next_scan_state = SCAN_SET_CHANNEL;
 740 }
 741
 742 void ieee80211_scan_work(struct work_struct *work)
 743 {
 744         struct ieee80211_local *local =
 745                 container_of(work, struct ieee80211_local, scan_work.work);
 746         struct ieee80211_sub_if_data *sdata;
 747         unsigned long next_delay = 0;
 748         bool aborted, hw_scan;
 749
 750         mutex_lock(&local->mtx);
 751
 752         sdata = rcu_dereference_protected(local->scan_sdata,
 753                                           lockdep_is_held(&local->mtx));
 754
 755         /* When scanning on-channel, the first-callback means completed. */
 756         if (test_bit(SCAN_ONCHANNEL_SCANNING, &local->scanning)) {
 757                 aborted = test_and_clear_bit(SCAN_ABORTED, &local->scanning);
 758                 goto out_complete;
 759         }
 760
 761         if (test_and_clear_bit(SCAN_COMPLETED, &local->scanning)) {
 762                 aborted = test_and_clear_bit(SCAN_ABORTED, &local->scanning);
 763                 goto out_complete;
 764         }
 765
 766         if (!sdata || !local->scan_req)
 767                 goto out;
 768
 769         if (local->scan_req && !local->scanning) {
 770                 struct cfg80211_scan_request *req = local->scan_req;
 771                 int rc;
 772
 773                 local->scan_req = NULL;
 774                 rcu_assign_pointer(local->scan_sdata, NULL);
 775
 776                 rc = __ieee80211_start_scan(sdata, req);
 777                 if (rc) {
 778                         /* need to complete scan in cfg80211 */
 779                         local->scan_req = req;
 780                         aborted = true;
 781                         goto out_complete;
 782                 } else
 783                         goto out;
 784         }
 785
 786         /*
 787          * Avoid re-scheduling when the sdata is going away.
 788          */
 789         if (!ieee80211_sdata_running(sdata)) {
 790                 aborted = true;
 791                 goto out_complete;
 792         }
 793
 794         /*
 795          * as long as no delay is required advance immediately
 796          * without scheduling a new work
 797          */
 798         do {
 799                 if (!ieee80211_sdata_running(sdata)) {
 800                         aborted = true;
 801                         goto out_complete;
 802                 }
 803
 804                 switch (local->next_scan_state) {
 805                 case SCAN_DECISION:
 806                         /* if no more bands/channels left, complete scan */
 807                         if (local->scan_channel_idx >= local->scan_req->n_channels) {
 808                                 aborted = false;
 809                                 goto out_complete;
 810                         }
 811                         ieee80211_scan_state_decision(local, &next_delay);
 812                         break;
 813                 case SCAN_SET_CHANNEL:
 814                         ieee80211_scan_state_set_channel(local, &next_delay);
 815                         break;
 816                 case SCAN_SEND_PROBE:
 817                         ieee80211_scan_state_send_probe(local, &next_delay);
 818                         break;
 819                 case SCAN_SUSPEND:
 820                         ieee80211_scan_state_suspend(local, &next_delay);
 821                         break;
 822                 case SCAN_RESUME:
 823                         ieee80211_scan_state_resume(local, &next_delay);
 824                         break;
 825                 case SCAN_ABORT:
 826                         aborted = true;
 827                         goto out_complete;
 828                 }
 829         } while (next_delay == 0);
 830
 831         ieee80211_queue_delayed_work(&local->hw, &local->scan_work, next_delay);
 832         goto out;
 833
 834 out_complete:
 835         hw_scan = test_bit(SCAN_HW_SCANNING, &local->scanning);
 836         __ieee80211_scan_completed(&local->hw, aborted, hw_scan);
 837 out:
 838         mutex_unlock(&local->mtx);
 839 }
 840
 841 int ieee80211_request_scan(struct ieee80211_sub_if_data *sdata,
 842                            struct cfg80211_scan_request *req)
 843 {
 844         int res;
 845
 846         mutex_lock(&sdata->local->mtx);
 847         res = __ieee80211_start_scan(sdata, req);
 848         mutex_unlock(&sdata->local->mtx);
 849
 850         return res;
 851 }
 852
 853 int ieee80211_request_ibss_scan(struct ieee80211_sub_if_data *sdata,
 854                                 const u8 *ssid, u8 ssid_len,
 855                                 struct ieee80211_channel *chan,
 856                                 enum nl80211_bss_scan_width scan_width)
 857 {
 858         struct ieee80211_local *local = sdata->local;
 859         int ret = -EBUSY;
 860         enum ieee80211_band band;
 861
 862         mutex_lock(&local->mtx);
 863
 864         /* busy scanning */
 865         if (local->scan_req)
 866                 goto unlock;
 867
 868         /* fill internal scan request */
 869         if (!chan) {
 870                 int i, max_n;
 871                 int n_ch = 0;
 872
 873                 for (band = 0; band < IEEE80211_NUM_BANDS; band++) {
 874                         if (!local->hw.wiphy->bands[band])
 875                                 continue;
 876
 877                         max_n = local->hw.wiphy->bands[band]->n_channels;
 878                         for (i = 0; i < max_n; i++) {
 879                                 struct ieee80211_channel *tmp_ch =
 880                                     &local->hw.wiphy->bands[band]->channels[i];
 881
 882                                 if (tmp_ch->flags & (IEEE80211_CHAN_NO_IBSS |
 883                                                      IEEE80211_CHAN_DISABLED))
 884                                         continue;
 885
 886                                 local->int_scan_req->channels[n_ch] = tmp_ch;
 887                                 n_ch++;
 888                         }
 889                 }
 890
 891                 if (WARN_ON_ONCE(n_ch == 0))
 892                         goto unlock;
 893
 894                 local->int_scan_req->n_channels = n_ch;
 895         } else {
 896                 if (WARN_ON_ONCE(chan->flags & (IEEE80211_CHAN_NO_IBSS |
 897                                                 IEEE80211_CHAN_DISABLED)))
 898                         goto unlock;
 899
 900                 local->int_scan_req->channels[0] = chan;
 901                 local->int_scan_req->n_channels = 1;
 902         }
 903
 904         local->int_scan_req->ssids = &local->scan_ssid;
 905         local->int_scan_req->n_ssids = 1;
 906         local->int_scan_req->scan_width = scan_width;
 907         memcpy(local->int_scan_req->ssids[0].ssid, ssid, IEEE80211_MAX_SSID_LEN);
 908         local->int_scan_req->ssids[0].ssid_len = ssid_len;
 909
 910         ret = __ieee80211_start_scan(sdata, sdata->local->int_scan_req);
 911  unlock:
 912         mutex_unlock(&local->mtx);
 913         return ret;
 914 }
 915
 916 /*
 917  * Only call this function when a scan can't be queued -- under RTNL.
 918  */
 919 void ieee80211_scan_cancel(struct ieee80211_local *local)
 920 {
 921         /*
 922          * We are canceling software scan, or deferred scan that was not
 923          * yet really started (see __ieee80211_start_scan ).
 924          *
 925          * Regarding hardware scan:
 926          * - we can not call  __ieee80211_scan_completed() as when
 927          *   SCAN_HW_SCANNING bit is set this function change
 928          *   local->hw_scan_req to operate on 5G band, what race with
 929          *   driver which can use local->hw_scan_req
 930          *
 931          * - we can not cancel scan_work since driver can schedule it
 932          *   by ieee80211_scan_completed(..., true) to finish scan
 933          *
 934          * Hence we only call the cancel_hw_scan() callback, but the low-level
 935          * driver is still responsible for calling ieee80211_scan_completed()
 936          * after the scan was completed/aborted.
 937          */
 938
 939         mutex_lock(&local->mtx);
 940         if (!local->scan_req)
 941                 goto out;
 942
 943         if (test_bit(SCAN_HW_SCANNING, &local->scanning)) {
 944                 if (local->ops->cancel_hw_scan)
 945                         drv_cancel_hw_scan(local,
 946                                 rcu_dereference_protected(local->scan_sdata,
 947                                                 lockdep_is_held(&local->mtx)));
 948                 goto out;
 949         }
 950
 951         /*
 952          * If the work is currently running, it must be blocked on
 953          * the mutex, but we'll set scan_sdata = NULL and it'll
 954          * simply exit once it acquires the mutex.
 955          */
 956         cancel_delayed_work(&local->scan_work);
 957         /* and clean up */
 958         __ieee80211_scan_completed(&local->hw, true, false);
 959 out:
 960         mutex_unlock(&local->mtx);
 961 }
 962
 963 int ieee80211_request_sched_scan_start(struct ieee80211_sub_if_data *sdata,
 964                                        struct cfg80211_sched_scan_request *req)
 965 {
 966         struct ieee80211_local *local = sdata->local;
 967         struct ieee80211_sched_scan_ies sched_scan_ies = {};
 968         struct cfg80211_chan_def chandef;
 969         int ret, i, iebufsz;
 970
 971         iebufsz = 2 + IEEE80211_MAX_SSID_LEN +
 972                   local->scan_ies_len + req->ie_len;
 973
 974         mutex_lock(&local->mtx);
 975
 976         if (rcu_access_pointer(local->sched_scan_sdata)) {
 977                 ret = -EBUSY;
 978                 goto out;
 979         }
 980
 981         if (!local->ops->sched_scan_start) {
 982                 ret = -ENOTSUPP;
 983                 goto out;
 984         }
 985
 986         for (i = 0; i < IEEE80211_NUM_BANDS; i++) {
 987                 if (!local->hw.wiphy->bands[i])
 988                         continue;
 989
 990                 sched_scan_ies.ie[i] = kzalloc(iebufsz, GFP_KERNEL);
 991                 if (!sched_scan_ies.ie[i]) {
 992                         ret = -ENOMEM;
 993                         goto out_free;
 994                 }
 995
 996                 ieee80211_prepare_scan_chandef(&chandef, req->scan_width);
 997
 998                 sched_scan_ies.len[i] =
 999                         ieee80211_build_preq_ies(local, sched_scan_ies.ie[i],
1000                                                  iebufsz, req->ie, req->ie_len,
1001                                                  i, (u32) -1, &chandef);
1002         }
1003
1004         ret = drv_sched_scan_start(local, sdata, req, &sched_scan_ies);
1005         if (ret == 0)
1006                 rcu_assign_pointer(local->sched_scan_sdata, sdata);
1007
1008 out_free:
1009         while (i > 0)
1010                 kfree(sched_scan_ies.ie[--i]);
1011 out:
1012         mutex_unlock(&local->mtx);
1013         return ret;
1014 }
1015
1016 int ieee80211_request_sched_scan_stop(struct ieee80211_sub_if_data *sdata)
1017 {
1018         struct ieee80211_local *local = sdata->local;
1019         int ret = 0;
1020
1021         mutex_lock(&local->mtx);
1022
1023         if (!local->ops->sched_scan_stop) {
1024                 ret = -ENOTSUPP;
1025                 goto out;
1026         }
1027
1028         if (rcu_access_pointer(local->sched_scan_sdata))
1029                 drv_sched_scan_stop(local, sdata);
1030
1031 out:
1032         mutex_unlock(&local->mtx);
1033
1034         return ret;
1035 }
1036
1037 void ieee80211_sched_scan_results(struct ieee80211_hw *hw)
1038 {
1039         struct ieee80211_local *local = hw_to_local(hw);
1040
1041         trace_api_sched_scan_results(local);
1042
1043         cfg80211_sched_scan_results(hw->wiphy);
1044 }
1045 EXPORT_SYMBOL(ieee80211_sched_scan_results);
1046
1047 void ieee80211_sched_scan_stopped_work(struct work_struct *work)
1048 {
1049         struct ieee80211_local *local =
1050                 container_of(work, struct ieee80211_local,
1051                              sched_scan_stopped_work);
1052
1053         mutex_lock(&local->mtx);
1054
1055         if (!rcu_access_pointer(local->sched_scan_sdata)) {
1056                 mutex_unlock(&local->mtx);
1057                 return;
1058         }
1059
1060         rcu_assign_pointer(local->sched_scan_sdata, NULL);
1061
1062         mutex_unlock(&local->mtx);
1063
1064         cfg80211_sched_scan_stopped(local->hw.wiphy);
1065 }
1066
1067 void ieee80211_sched_scan_stopped(struct ieee80211_hw *hw)
1068 {
1069         struct ieee80211_local *local = hw_to_local(hw);
1070
1071         trace_api_sched_scan_stopped(local);
1072
1073         ieee80211_queue_work(&local->hw, &local->sched_scan_stopped_work);
1074 }
1075 EXPORT_SYMBOL(ieee80211_sched_scan_stopped);