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         if (test_bit(SCAN_HW_CANCELLED, &local->scanning))
 242                 return false;
 243
 244         do {
 245                 if (local->hw_scan_band == IEEE80211_NUM_BANDS)
 246                         return false;
 247
 248                 band = local->hw_scan_band;
 249                 n_chans = 0;
 250                 for (i = 0; i < req->n_channels; i++) {
 251                         if (req->channels[i]->band == band) {
 252                                 local->hw_scan_req->channels[n_chans] =
 253                                                         req->channels[i];
 254                                 n_chans++;
 255                         }
 256                 }
 257
 258                 local->hw_scan_band++;
 259         } while (!n_chans);
 260
 261         local->hw_scan_req->n_channels = n_chans;
 262         ieee80211_prepare_scan_chandef(&chandef, req->scan_width);
 263
 264         ielen = ieee80211_build_preq_ies(local, (u8 *)local->hw_scan_req->ie,
 265                                          local->hw_scan_ies_bufsize,
 266                                          req->ie, req->ie_len, band,
 267                                          req->rates[band], &chandef);
 268         local->hw_scan_req->ie_len = ielen;
 269         local->hw_scan_req->no_cck = req->no_cck;
 270
 271         return true;
 272 }
 273
 274 static void __ieee80211_scan_completed(struct ieee80211_hw *hw, bool aborted,
 275                                        bool was_hw_scan)
 276 {
 277         struct ieee80211_local *local = hw_to_local(hw);
 278
 279         lockdep_assert_held(&local->mtx);
 280
 281         /*
 282          * It's ok to abort a not-yet-running scan (that
 283          * we have one at all will be verified by checking
 284          * local->scan_req next), but not to complete it
 285          * successfully.
 286          */
 287         if (WARN_ON(!local->scanning && !aborted))
 288                 aborted = true;
 289
 290         if (WARN_ON(!local->scan_req))
 291                 return;
 292
 293         if (was_hw_scan && !aborted && ieee80211_prep_hw_scan(local)) {
 294                 int rc;
 295
 296                 rc = drv_hw_scan(local,
 297                         rcu_dereference_protected(local->scan_sdata,
 298                                                   lockdep_is_held(&local->mtx)),
 299                         local->hw_scan_req);
 300
 301                 if (rc == 0)
 302                         return;
 303         }
 304
 305         kfree(local->hw_scan_req);
 306         local->hw_scan_req = NULL;
 307
 308         if (local->scan_req != local->int_scan_req)
 309                 cfg80211_scan_done(local->scan_req, aborted);
 310         local->scan_req = NULL;
 311         rcu_assign_pointer(local->scan_sdata, NULL);
 312
 313         local->scanning = 0;
 314         local->scan_chandef.chan = NULL;
 315
 316         /* Set power back to normal operating levels. */
 317         ieee80211_hw_config(local, 0);
 318
 319         if (!was_hw_scan) {
 320                 ieee80211_configure_filter(local);
 321                 drv_sw_scan_complete(local);
 322                 ieee80211_offchannel_return(local);
 323         }
 324
 325         ieee80211_recalc_idle(local);
 326
 327         ieee80211_mlme_notify_scan_completed(local);
 328         ieee80211_ibss_notify_scan_completed(local);
 329         ieee80211_mesh_notify_scan_completed(local);
 330         ieee80211_start_next_roc(local);
 331 }
 332
 333 void ieee80211_scan_completed(struct ieee80211_hw *hw, bool aborted)
 334 {
 335         struct ieee80211_local *local = hw_to_local(hw);
 336
 337         trace_api_scan_completed(local, aborted);
 338
 339         set_bit(SCAN_COMPLETED, &local->scanning);
 340         if (aborted)
 341                 set_bit(SCAN_ABORTED, &local->scanning);
 342         ieee80211_queue_delayed_work(&local->hw, &local->scan_work, 0);
 343 }
 344 EXPORT_SYMBOL(ieee80211_scan_completed);
 345
 346 static int ieee80211_start_sw_scan(struct ieee80211_local *local)
 347 {
 348         /* Software scan is not supported in multi-channel cases */
 349         if (local->use_chanctx)
 350                 return -EOPNOTSUPP;
 351
 352         /*
 353          * Hardware/driver doesn't support hw_scan, so use software
 354          * scanning instead. First send a nullfunc frame with power save
 355          * bit on so that AP will buffer the frames for us while we are not
 356          * listening, then send probe requests to each channel and wait for
 357          * the responses. After all channels are scanned, tune back to the
 358          * original channel and send a nullfunc frame with power save bit
 359          * off to trigger the AP to send us all the buffered frames.
 360          *
 361          * Note that while local->sw_scanning is true everything else but
 362          * nullfunc frames and probe requests will be dropped in
 363          * ieee80211_tx_h_check_assoc().
 364          */
 365         drv_sw_scan_start(local);
 366
 367         local->leave_oper_channel_time = jiffies;
 368         local->next_scan_state = SCAN_DECISION;
 369         local->scan_channel_idx = 0;
 370
 371         ieee80211_offchannel_stop_vifs(local);
 372
 373         /* ensure nullfunc is transmitted before leaving operating channel */
 374         ieee80211_flush_queues(local, NULL);
 375
 376         ieee80211_configure_filter(local);
 377
 378         /* We need to set power level at maximum rate for scanning. */
 379         ieee80211_hw_config(local, 0);
 380
 381         ieee80211_queue_delayed_work(&local->hw,
 382                                      &local->scan_work, 0);
 383
 384         return 0;
 385 }
 386
 387 static bool ieee80211_can_scan(struct ieee80211_local *local,
 388                                struct ieee80211_sub_if_data *sdata)
 389 {
 390         if (local->radar_detect_enabled)
 391                 return false;
 392
 393         if (!list_empty(&local->roc_list))
 394                 return false;
 395
 396         if (sdata->vif.type == NL80211_IFTYPE_STATION &&
 397             sdata->u.mgd.flags & (IEEE80211_STA_BEACON_POLL |
 398                                   IEEE80211_STA_CONNECTION_POLL))
 399                 return false;
 400
 401         return true;
 402 }
 403
 404 void ieee80211_run_deferred_scan(struct ieee80211_local *local)
 405 {
 406         lockdep_assert_held(&local->mtx);
 407
 408         if (!local->scan_req || local->scanning)
 409                 return;
 410
 411         if (!ieee80211_can_scan(local,
 412                                 rcu_dereference_protected(
 413                                         local->scan_sdata,
 414                                         lockdep_is_held(&local->mtx))))
 415                 return;
 416
 417         ieee80211_queue_delayed_work(&local->hw, &local->scan_work,
 418                                      round_jiffies_relative(0));
 419 }
 420
 421 static void ieee80211_scan_state_send_probe(struct ieee80211_local *local,
 422                                             unsigned long *next_delay)
 423 {
 424         int i;
 425         struct ieee80211_sub_if_data *sdata;
 426         enum ieee80211_band band = local->hw.conf.chandef.chan->band;
 427         u32 tx_flags;
 428
 429         tx_flags = IEEE80211_TX_INTFL_OFFCHAN_TX_OK;
 430         if (local->scan_req->no_cck)
 431                 tx_flags |= IEEE80211_TX_CTL_NO_CCK_RATE;
 432
 433         sdata = rcu_dereference_protected(local->scan_sdata,
 434                                           lockdep_is_held(&local->mtx));
 435
 436         for (i = 0; i < local->scan_req->n_ssids; i++)
 437                 ieee80211_send_probe_req(
 438                         sdata, NULL,
 439                         local->scan_req->ssids[i].ssid,
 440                         local->scan_req->ssids[i].ssid_len,
 441                         local->scan_req->ie, local->scan_req->ie_len,
 442                         local->scan_req->rates[band], false,
 443                         tx_flags, local->hw.conf.chandef.chan, true);
 444
 445         /*
 446          * After sending probe requests, wait for probe responses
 447          * on the channel.
 448          */
 449         *next_delay = IEEE80211_CHANNEL_TIME;
 450         local->next_scan_state = SCAN_DECISION;
 451 }
 452
 453 static int __ieee80211_start_scan(struct ieee80211_sub_if_data *sdata,
 454                                   struct cfg80211_scan_request *req)
 455 {
 456         struct ieee80211_local *local = sdata->local;
 457         int rc;
 458
 459         lockdep_assert_held(&local->mtx);
 460
 461         if (local->scan_req)
 462                 return -EBUSY;
 463
 464         if (!ieee80211_can_scan(local, sdata)) {
 465                 /* wait for the work to finish/time out */
 466                 local->scan_req = req;
 467                 rcu_assign_pointer(local->scan_sdata, sdata);
 468                 return 0;
 469         }
 470
 471         if (local->ops->hw_scan) {
 472                 u8 *ies;
 473
 474                 local->hw_scan_ies_bufsize = 2 + IEEE80211_MAX_SSID_LEN +
 475                                              local->scan_ies_len +
 476                                              req->ie_len;
 477                 local->hw_scan_req = kmalloc(
 478                                 sizeof(*local->hw_scan_req) +
 479                                 req->n_channels * sizeof(req->channels[0]) +
 480                                 local->hw_scan_ies_bufsize, GFP_KERNEL);
 481                 if (!local->hw_scan_req)
 482                         return -ENOMEM;
 483
 484                 local->hw_scan_req->ssids = req->ssids;
 485                 local->hw_scan_req->n_ssids = req->n_ssids;
 486                 ies = (u8 *)local->hw_scan_req +
 487                         sizeof(*local->hw_scan_req) +
 488                         req->n_channels * sizeof(req->channels[0]);
 489                 local->hw_scan_req->ie = ies;
 490                 local->hw_scan_req->flags = req->flags;
 491
 492                 local->hw_scan_band = 0;
 493
 494                 /*
 495                  * After allocating local->hw_scan_req, we must
 496                  * go through until ieee80211_prep_hw_scan(), so
 497                  * anything that might be changed here and leave
 498                  * this function early must not go after this
 499                  * allocation.
 500                  */
 501         }
 502
 503         local->scan_req = req;
 504         rcu_assign_pointer(local->scan_sdata, sdata);
 505
 506         if (local->ops->hw_scan) {
 507                 __set_bit(SCAN_HW_SCANNING, &local->scanning);
 508         } else if ((req->n_channels == 1) &&
 509                    (req->channels[0] == local->_oper_chandef.chan)) {
 510                 /*
 511                  * If we are scanning only on the operating channel
 512                  * then we do not need to stop normal activities
 513                  */
 514                 unsigned long next_delay;
 515
 516                 __set_bit(SCAN_ONCHANNEL_SCANNING, &local->scanning);
 517
 518                 ieee80211_recalc_idle(local);
 519
 520                 /* Notify driver scan is starting, keep order of operations
 521                  * same as normal software scan, in case that matters. */
 522                 drv_sw_scan_start(local);
 523
 524                 ieee80211_configure_filter(local); /* accept probe-responses */
 525
 526                 /* We need to ensure power level is at max for scanning. */
 527                 ieee80211_hw_config(local, 0);
 528
 529                 if ((req->channels[0]->flags &
 530                      IEEE80211_CHAN_PASSIVE_SCAN) ||
 531                     !local->scan_req->n_ssids) {
 532                         next_delay = IEEE80211_PASSIVE_CHANNEL_TIME;
 533                 } else {
 534                         ieee80211_scan_state_send_probe(local, &next_delay);
 535                         next_delay = IEEE80211_CHANNEL_TIME;
 536                 }
 537
 538                 /* Now, just wait a bit and we are all done! */
 539                 ieee80211_queue_delayed_work(&local->hw, &local->scan_work,
 540                                              next_delay);
 541                 return 0;
 542         } else {
 543                 /* Do normal software scan */
 544                 __set_bit(SCAN_SW_SCANNING, &local->scanning);
 545         }
 546
 547         ieee80211_recalc_idle(local);
 548
 549         if (local->ops->hw_scan) {
 550                 WARN_ON(!ieee80211_prep_hw_scan(local));
 551                 rc = drv_hw_scan(local, sdata, local->hw_scan_req);
 552         } else
 553                 rc = ieee80211_start_sw_scan(local);
 554
 555         if (rc) {
 556                 kfree(local->hw_scan_req);
 557                 local->hw_scan_req = NULL;
 558                 local->scanning = 0;
 559
 560                 ieee80211_recalc_idle(local);
 561
 562                 local->scan_req = NULL;
 563                 rcu_assign_pointer(local->scan_sdata, NULL);
 564         }
 565
 566         return rc;
 567 }
 568
 569 static unsigned long
 570 ieee80211_scan_get_channel_time(struct ieee80211_channel *chan)
 571 {
 572         /*
 573          * TODO: channel switching also consumes quite some time,
 574          * add that delay as well to get a better estimation
 575          */
 576         if (chan->flags & IEEE80211_CHAN_PASSIVE_SCAN)
 577                 return IEEE80211_PASSIVE_CHANNEL_TIME;
 578         return IEEE80211_PROBE_DELAY + IEEE80211_CHANNEL_TIME;
 579 }
 580
 581 static void ieee80211_scan_state_decision(struct ieee80211_local *local,
 582                                           unsigned long *next_delay)
 583 {
 584         bool associated = false;
 585         bool tx_empty = true;
 586         bool bad_latency;
 587         struct ieee80211_sub_if_data *sdata;
 588         struct ieee80211_channel *next_chan;
 589         enum mac80211_scan_state next_scan_state;
 590
 591         /*
 592          * check if at least one STA interface is associated,
 593          * check if at least one STA interface has pending tx frames
 594          * and grab the lowest used beacon interval
 595          */
 596         mutex_lock(&local->iflist_mtx);
 597         list_for_each_entry(sdata, &local->interfaces, list) {
 598                 if (!ieee80211_sdata_running(sdata))
 599                         continue;
 600
 601                 if (sdata->vif.type == NL80211_IFTYPE_STATION) {
 602                         if (sdata->u.mgd.associated) {
 603                                 associated = true;
 604
 605                                 if (!qdisc_all_tx_empty(sdata->dev)) {
 606                                         tx_empty = false;
 607                                         break;
 608                                 }
 609                         }
 610                 }
 611         }
 612         mutex_unlock(&local->iflist_mtx);
 613
 614         next_chan = local->scan_req->channels[local->scan_channel_idx];
 615
 616         /*
 617          * we're currently scanning a different channel, let's
 618          * see if we can scan another channel without interfering
 619          * with the current traffic situation.
 620          *
 621          * Keep good latency, do not stay off-channel more than 125 ms.
 622          */
 623
 624         bad_latency = time_after(jiffies +
 625                                  ieee80211_scan_get_channel_time(next_chan),
 626                                  local->leave_oper_channel_time + HZ / 8);
 627
 628         if (associated && !tx_empty) {
 629                 if (local->scan_req->flags & NL80211_SCAN_FLAG_LOW_PRIORITY)
 630                         next_scan_state = SCAN_ABORT;
 631                 else
 632                         next_scan_state = SCAN_SUSPEND;
 633         } else if (associated && bad_latency) {
 634                 next_scan_state = SCAN_SUSPEND;
 635         } else {
 636                 next_scan_state = SCAN_SET_CHANNEL;
 637         }
 638
 639         local->next_scan_state = next_scan_state;
 640
 641         *next_delay = 0;
 642 }
 643
 644 static void ieee80211_scan_state_set_channel(struct ieee80211_local *local,
 645                                              unsigned long *next_delay)
 646 {
 647         int skip;
 648         struct ieee80211_channel *chan;
 649         enum nl80211_bss_scan_width oper_scan_width;
 650
 651         skip = 0;
 652         chan = local->scan_req->channels[local->scan_channel_idx];
 653
 654         local->scan_chandef.chan = chan;
 655         local->scan_chandef.center_freq1 = chan->center_freq;
 656         local->scan_chandef.center_freq2 = 0;
 657         switch (local->scan_req->scan_width) {
 658         case NL80211_BSS_CHAN_WIDTH_5:
 659                 local->scan_chandef.width = NL80211_CHAN_WIDTH_5;
 660                 break;
 661         case NL80211_BSS_CHAN_WIDTH_10:
 662                 local->scan_chandef.width = NL80211_CHAN_WIDTH_10;
 663                 break;
 664         case NL80211_BSS_CHAN_WIDTH_20:
 665                 /* If scanning on oper channel, use whatever channel-type
 666                  * is currently in use.
 667                  */
 668                 oper_scan_width = cfg80211_chandef_to_scan_width(
 669                                         &local->_oper_chandef);
 670                 if (chan == local->_oper_chandef.chan &&
 671                     oper_scan_width == local->scan_req->scan_width)
 672                         local->scan_chandef = local->_oper_chandef;
 673                 else
 674                         local->scan_chandef.width = NL80211_CHAN_WIDTH_20_NOHT;
 675                 break;
 676         }
 677
 678         if (ieee80211_hw_config(local, IEEE80211_CONF_CHANGE_CHANNEL))
 679                 skip = 1;
 680
 681         /* advance state machine to next channel/band */
 682         local->scan_channel_idx++;
 683
 684         if (skip) {
 685                 /* if we skip this channel return to the decision state */
 686                 local->next_scan_state = SCAN_DECISION;
 687                 return;
 688         }
 689
 690         /*
 691          * Probe delay is used to update the NAV, cf. 11.1.3.2.2
 692          * (which unfortunately doesn't say _why_ step a) is done,
 693          * but it waits for the probe delay or until a frame is
 694          * received - and the received frame would update the NAV).
 695          * For now, we do not support waiting until a frame is
 696          * received.
 697          *
 698          * In any case, it is not necessary for a passive scan.
 699          */
 700         if (chan->flags & IEEE80211_CHAN_PASSIVE_SCAN ||
 701             !local->scan_req->n_ssids) {
 702                 *next_delay = IEEE80211_PASSIVE_CHANNEL_TIME;
 703                 local->next_scan_state = SCAN_DECISION;
 704                 return;
 705         }
 706
 707         /* active scan, send probes */
 708         *next_delay = IEEE80211_PROBE_DELAY;
 709         local->next_scan_state = SCAN_SEND_PROBE;
 710 }
 711
 712 static void ieee80211_scan_state_suspend(struct ieee80211_local *local,
 713                                          unsigned long *next_delay)
 714 {
 715         /* switch back to the operating channel */
 716         local->scan_chandef.chan = NULL;
 717         ieee80211_hw_config(local, IEEE80211_CONF_CHANGE_CHANNEL);
 718
 719         /* disable PS */
 720         ieee80211_offchannel_return(local);
 721
 722         *next_delay = HZ / 5;
 723         /* afterwards, resume scan & go to next channel */
 724         local->next_scan_state = SCAN_RESUME;
 725 }
 726
 727 static void ieee80211_scan_state_resume(struct ieee80211_local *local,
 728                                         unsigned long *next_delay)
 729 {
 730         ieee80211_offchannel_stop_vifs(local);
 731
 732         if (local->ops->flush) {
 733                 ieee80211_flush_queues(local, NULL);
 734                 *next_delay = 0;
 735         } else
 736                 *next_delay = HZ / 10;
 737
 738         /* remember when we left the operating channel */
 739         local->leave_oper_channel_time = jiffies;
 740
 741         /* advance to the next channel to be scanned */
 742         local->next_scan_state = SCAN_SET_CHANNEL;
 743 }
 744
 745 void ieee80211_scan_work(struct work_struct *work)
 746 {
 747         struct ieee80211_local *local =
 748                 container_of(work, struct ieee80211_local, scan_work.work);
 749         struct ieee80211_sub_if_data *sdata;
 750         unsigned long next_delay = 0;
 751         bool aborted, hw_scan;
 752
 753         mutex_lock(&local->mtx);
 754
 755         sdata = rcu_dereference_protected(local->scan_sdata,
 756                                           lockdep_is_held(&local->mtx));
 757
 758         /* When scanning on-channel, the first-callback means completed. */
 759         if (test_bit(SCAN_ONCHANNEL_SCANNING, &local->scanning)) {
 760                 aborted = test_and_clear_bit(SCAN_ABORTED, &local->scanning);
 761                 goto out_complete;
 762         }
 763
 764         if (test_and_clear_bit(SCAN_COMPLETED, &local->scanning)) {
 765                 aborted = test_and_clear_bit(SCAN_ABORTED, &local->scanning);
 766                 goto out_complete;
 767         }
 768
 769         if (!sdata || !local->scan_req)
 770                 goto out;
 771
 772         if (local->scan_req && !local->scanning) {
 773                 struct cfg80211_scan_request *req = local->scan_req;
 774                 int rc;
 775
 776                 local->scan_req = NULL;
 777                 rcu_assign_pointer(local->scan_sdata, NULL);
 778
 779                 rc = __ieee80211_start_scan(sdata, req);
 780                 if (rc) {
 781                         /* need to complete scan in cfg80211 */
 782                         local->scan_req = req;
 783                         aborted = true;
 784                         goto out_complete;
 785                 } else
 786                         goto out;
 787         }
 788
 789         /*
 790          * Avoid re-scheduling when the sdata is going away.
 791          */
 792         if (!ieee80211_sdata_running(sdata)) {
 793                 aborted = true;
 794                 goto out_complete;
 795         }
 796
 797         /*
 798          * as long as no delay is required advance immediately
 799          * without scheduling a new work
 800          */
 801         do {
 802                 if (!ieee80211_sdata_running(sdata)) {
 803                         aborted = true;
 804                         goto out_complete;
 805                 }
 806
 807                 switch (local->next_scan_state) {
 808                 case SCAN_DECISION:
 809                         /* if no more bands/channels left, complete scan */
 810                         if (local->scan_channel_idx >= local->scan_req->n_channels) {
 811                                 aborted = false;
 812                                 goto out_complete;
 813                         }
 814                         ieee80211_scan_state_decision(local, &next_delay);
 815                         break;
 816                 case SCAN_SET_CHANNEL:
 817                         ieee80211_scan_state_set_channel(local, &next_delay);
 818                         break;
 819                 case SCAN_SEND_PROBE:
 820                         ieee80211_scan_state_send_probe(local, &next_delay);
 821                         break;
 822                 case SCAN_SUSPEND:
 823                         ieee80211_scan_state_suspend(local, &next_delay);
 824                         break;
 825                 case SCAN_RESUME:
 826                         ieee80211_scan_state_resume(local, &next_delay);
 827                         break;
 828                 case SCAN_ABORT:
 829                         aborted = true;
 830                         goto out_complete;
 831                 }
 832         } while (next_delay == 0);
 833
 834         ieee80211_queue_delayed_work(&local->hw, &local->scan_work, next_delay);
 835         goto out;
 836
 837 out_complete:
 838         hw_scan = test_bit(SCAN_HW_SCANNING, &local->scanning);
 839         __ieee80211_scan_completed(&local->hw, aborted, hw_scan);
 840 out:
 841         mutex_unlock(&local->mtx);
 842 }
 843
 844 int ieee80211_request_scan(struct ieee80211_sub_if_data *sdata,
 845                            struct cfg80211_scan_request *req)
 846 {
 847         int res;
 848
 849         mutex_lock(&sdata->local->mtx);
 850         res = __ieee80211_start_scan(sdata, req);
 851         mutex_unlock(&sdata->local->mtx);
 852
 853         return res;
 854 }
 855
 856 int ieee80211_request_ibss_scan(struct ieee80211_sub_if_data *sdata,
 857                                 const u8 *ssid, u8 ssid_len,
 858                                 struct ieee80211_channel *chan,
 859                                 enum nl80211_bss_scan_width scan_width)
 860 {
 861         struct ieee80211_local *local = sdata->local;
 862         int ret = -EBUSY;
 863         enum ieee80211_band band;
 864
 865         mutex_lock(&local->mtx);
 866
 867         /* busy scanning */
 868         if (local->scan_req)
 869                 goto unlock;
 870
 871         /* fill internal scan request */
 872         if (!chan) {
 873                 int i, max_n;
 874                 int n_ch = 0;
 875
 876                 for (band = 0; band < IEEE80211_NUM_BANDS; band++) {
 877                         if (!local->hw.wiphy->bands[band])
 878                                 continue;
 879
 880                         max_n = local->hw.wiphy->bands[band]->n_channels;
 881                         for (i = 0; i < max_n; i++) {
 882                                 struct ieee80211_channel *tmp_ch =
 883                                     &local->hw.wiphy->bands[band]->channels[i];
 884
 885                                 if (tmp_ch->flags & (IEEE80211_CHAN_NO_IBSS |
 886                                                      IEEE80211_CHAN_DISABLED))
 887                                         continue;
 888
 889                                 local->int_scan_req->channels[n_ch] = tmp_ch;
 890                                 n_ch++;
 891                         }
 892                 }
 893
 894                 if (WARN_ON_ONCE(n_ch == 0))
 895                         goto unlock;
 896
 897                 local->int_scan_req->n_channels = n_ch;
 898         } else {
 899                 if (WARN_ON_ONCE(chan->flags & (IEEE80211_CHAN_NO_IBSS |
 900                                                 IEEE80211_CHAN_DISABLED)))
 901                         goto unlock;
 902
 903                 local->int_scan_req->channels[0] = chan;
 904                 local->int_scan_req->n_channels = 1;
 905         }
 906
 907         local->int_scan_req->ssids = &local->scan_ssid;
 908         local->int_scan_req->n_ssids = 1;
 909         local->int_scan_req->scan_width = scan_width;
 910         memcpy(local->int_scan_req->ssids[0].ssid, ssid, IEEE80211_MAX_SSID_LEN);
 911         local->int_scan_req->ssids[0].ssid_len = ssid_len;
 912
 913         ret = __ieee80211_start_scan(sdata, sdata->local->int_scan_req);
 914  unlock:
 915         mutex_unlock(&local->mtx);
 916         return ret;
 917 }
 918
 919 /*
 920  * Only call this function when a scan can't be queued -- under RTNL.
 921  */
 922 void ieee80211_scan_cancel(struct ieee80211_local *local)
 923 {
 924         /*
 925          * We are canceling software scan, or deferred scan that was not
 926          * yet really started (see __ieee80211_start_scan ).
 927          *
 928          * Regarding hardware scan:
 929          * - we can not call  __ieee80211_scan_completed() as when
 930          *   SCAN_HW_SCANNING bit is set this function change
 931          *   local->hw_scan_req to operate on 5G band, what race with
 932          *   driver which can use local->hw_scan_req
 933          *
 934          * - we can not cancel scan_work since driver can schedule it
 935          *   by ieee80211_scan_completed(..., true) to finish scan
 936          *
 937          * Hence we only call the cancel_hw_scan() callback, but the low-level
 938          * driver is still responsible for calling ieee80211_scan_completed()
 939          * after the scan was completed/aborted.
 940          */
 941
 942         mutex_lock(&local->mtx);
 943         if (!local->scan_req)
 944                 goto out;
 945
 946         /*
 947          * We have a scan running and the driver already reported completion,
 948          * but the worker hasn't run yet or is stuck on the mutex - mark it as
 949          * cancelled.
 950          */
 951         if (test_bit(SCAN_HW_SCANNING, &local->scanning) &&
 952             test_bit(SCAN_COMPLETED, &local->scanning)) {
 953                 set_bit(SCAN_HW_CANCELLED, &local->scanning);
 954                 goto out;
 955         }
 956
 957         if (test_bit(SCAN_HW_SCANNING, &local->scanning)) {
 958                 /*
 959                  * Make sure that __ieee80211_scan_completed doesn't trigger a
 960                  * scan on another band.
 961                  */
 962                 set_bit(SCAN_HW_CANCELLED, &local->scanning);
 963                 if (local->ops->cancel_hw_scan)
 964                         drv_cancel_hw_scan(local,
 965                                 rcu_dereference_protected(local->scan_sdata,
 966                                                 lockdep_is_held(&local->mtx)));
 967                 goto out;
 968         }
 969
 970         /*
 971          * If the work is currently running, it must be blocked on
 972          * the mutex, but we'll set scan_sdata = NULL and it'll
 973          * simply exit once it acquires the mutex.
 974          */
 975         cancel_delayed_work(&local->scan_work);
 976         /* and clean up */
 977         __ieee80211_scan_completed(&local->hw, true, false);
 978 out:
 979         mutex_unlock(&local->mtx);
 980 }
 981
 982 int ieee80211_request_sched_scan_start(struct ieee80211_sub_if_data *sdata,
 983                                        struct cfg80211_sched_scan_request *req)
 984 {
 985         struct ieee80211_local *local = sdata->local;
 986         struct ieee80211_sched_scan_ies sched_scan_ies = {};
 987         struct cfg80211_chan_def chandef;
 988         int ret, i, iebufsz;
 989
 990         iebufsz = 2 + IEEE80211_MAX_SSID_LEN +
 991                   local->scan_ies_len + req->ie_len;
 992
 993         mutex_lock(&local->mtx);
 994
 995         if (rcu_access_pointer(local->sched_scan_sdata)) {
 996                 ret = -EBUSY;
 997                 goto out;
 998         }
 999
1000         if (!local->ops->sched_scan_start) {
1001                 ret = -ENOTSUPP;
1002                 goto out;
1003         }
1004
1005         for (i = 0; i < IEEE80211_NUM_BANDS; i++) {
1006                 if (!local->hw.wiphy->bands[i])
1007                         continue;
1008
1009                 sched_scan_ies.ie[i] = kzalloc(iebufsz, GFP_KERNEL);
1010                 if (!sched_scan_ies.ie[i]) {
1011                         ret = -ENOMEM;
1012                         goto out_free;
1013                 }
1014
1015                 ieee80211_prepare_scan_chandef(&chandef, req->scan_width);
1016
1017                 sched_scan_ies.len[i] =
1018                         ieee80211_build_preq_ies(local, sched_scan_ies.ie[i],
1019                                                  iebufsz, req->ie, req->ie_len,
1020                                                  i, (u32) -1, &chandef);
1021         }
1022
1023         ret = drv_sched_scan_start(local, sdata, req, &sched_scan_ies);
1024         if (ret == 0)
1025                 rcu_assign_pointer(local->sched_scan_sdata, sdata);
1026
1027 out_free:
1028         while (i > 0)
1029                 kfree(sched_scan_ies.ie[--i]);
1030 out:
1031         mutex_unlock(&local->mtx);
1032         return ret;
1033 }
1034
1035 int ieee80211_request_sched_scan_stop(struct ieee80211_sub_if_data *sdata)
1036 {
1037         struct ieee80211_local *local = sdata->local;
1038         int ret = 0;
1039
1040         mutex_lock(&local->mtx);
1041
1042         if (!local->ops->sched_scan_stop) {
1043                 ret = -ENOTSUPP;
1044                 goto out;
1045         }
1046
1047         if (rcu_access_pointer(local->sched_scan_sdata))
1048                 drv_sched_scan_stop(local, sdata);
1049
1050 out:
1051         mutex_unlock(&local->mtx);
1052
1053         return ret;
1054 }
1055
1056 void ieee80211_sched_scan_results(struct ieee80211_hw *hw)
1057 {
1058         struct ieee80211_local *local = hw_to_local(hw);
1059
1060         trace_api_sched_scan_results(local);
1061
1062         cfg80211_sched_scan_results(hw->wiphy);
1063 }
1064 EXPORT_SYMBOL(ieee80211_sched_scan_results);
1065
1066 void ieee80211_sched_scan_stopped_work(struct work_struct *work)
1067 {
1068         struct ieee80211_local *local =
1069                 container_of(work, struct ieee80211_local,
1070                              sched_scan_stopped_work);
1071
1072         mutex_lock(&local->mtx);
1073
1074         if (!rcu_access_pointer(local->sched_scan_sdata)) {
1075                 mutex_unlock(&local->mtx);
1076                 return;
1077         }
1078
1079         rcu_assign_pointer(local->sched_scan_sdata, NULL);
1080
1081         mutex_unlock(&local->mtx);
1082
1083         cfg80211_sched_scan_stopped(local->hw.wiphy);
1084 }
1085
1086 void ieee80211_sched_scan_stopped(struct ieee80211_hw *hw)
1087 {
1088         struct ieee80211_local *local = hw_to_local(hw);
1089
1090         trace_api_sched_scan_stopped(local);
1091
1092         ieee80211_queue_work(&local->hw, &local->sched_scan_stopped_work);
1093 }
1094 EXPORT_SYMBOL(ieee80211_sched_scan_stopped);