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         u8 bands_used = 0;
 239         int i, ielen, n_chans;
 240
 241         if (test_bit(SCAN_HW_CANCELLED, &local->scanning))
 242                 return false;
 243
 244         if (local->hw.flags & IEEE80211_SINGLE_HW_SCAN_ON_ALL_BANDS) {
 245                 for (i = 0; i < req->n_channels; i++) {
 246                         local->hw_scan_req->req.channels[i] = req->channels[i];
 247                         bands_used |= BIT(req->channels[i]->band);
 248                 }
 249
 250                 n_chans = req->n_channels;
 251         } else {
 252                 do {
 253                         if (local->hw_scan_band == IEEE80211_NUM_BANDS)
 254                                 return false;
 255
 256                         n_chans = 0;
 257
 258                         for (i = 0; i < req->n_channels; i++) {
 259                                 if (req->channels[i]->band !=
 260                                     local->hw_scan_band)
 261                                         continue;
 262                                 local->hw_scan_req->req.channels[n_chans] =
 263                                                         req->channels[i];
 264                                 n_chans++;
 265                                 bands_used |= BIT(req->channels[i]->band);
 266                         }
 267
 268                         local->hw_scan_band++;
 269                 } while (!n_chans);
 270         }
 271
 272         local->hw_scan_req->req.n_channels = n_chans;
 273         ieee80211_prepare_scan_chandef(&chandef, req->scan_width);
 274
 275         ielen = ieee80211_build_preq_ies(local,
 276                                          (u8 *)local->hw_scan_req->req.ie,
 277                                          local->hw_scan_ies_bufsize,
 278                                          &local->hw_scan_req->ies,
 279                                          req->ie, req->ie_len,
 280                                          bands_used, req->rates, &chandef);
 281         local->hw_scan_req->req.ie_len = ielen;
 282         local->hw_scan_req->req.no_cck = req->no_cck;
 283
 284         return true;
 285 }
 286
 287 static void __ieee80211_scan_completed(struct ieee80211_hw *hw, bool aborted)
 288 {
 289         struct ieee80211_local *local = hw_to_local(hw);
 290         bool hw_scan = local->ops->hw_scan;
 291         bool was_scanning = local->scanning;
 292
 293         lockdep_assert_held(&local->mtx);
 294
 295         /*
 296          * It's ok to abort a not-yet-running scan (that
 297          * we have one at all will be verified by checking
 298          * local->scan_req next), but not to complete it
 299          * successfully.
 300          */
 301         if (WARN_ON(!local->scanning && !aborted))
 302                 aborted = true;
 303
 304         if (WARN_ON(!local->scan_req))
 305                 return;
 306
 307         if (hw_scan && !aborted &&
 308             !(local->hw.flags & IEEE80211_SINGLE_HW_SCAN_ON_ALL_BANDS) &&
 309             ieee80211_prep_hw_scan(local)) {
 310                 int rc;
 311
 312                 rc = drv_hw_scan(local,
 313                         rcu_dereference_protected(local->scan_sdata,
 314                                                   lockdep_is_held(&local->mtx)),
 315                         local->hw_scan_req);
 316
 317                 if (rc == 0)
 318                         return;
 319         }
 320
 321         kfree(local->hw_scan_req);
 322         local->hw_scan_req = NULL;
 323
 324         if (local->scan_req != local->int_scan_req)
 325                 cfg80211_scan_done(local->scan_req, aborted);
 326         local->scan_req = NULL;
 327         RCU_INIT_POINTER(local->scan_sdata, NULL);
 328
 329         local->scanning = 0;
 330         local->scan_chandef.chan = NULL;
 331
 332         /* Set power back to normal operating levels. */
 333         ieee80211_hw_config(local, 0);
 334
 335         if (!hw_scan) {
 336                 ieee80211_configure_filter(local);
 337                 drv_sw_scan_complete(local);
 338                 ieee80211_offchannel_return(local);
 339         }
 340
 341         ieee80211_recalc_idle(local);
 342
 343         ieee80211_mlme_notify_scan_completed(local);
 344         ieee80211_ibss_notify_scan_completed(local);
 345         ieee80211_mesh_notify_scan_completed(local);
 346         if (was_scanning)
 347                 ieee80211_start_next_roc(local);
 348 }
 349
 350 void ieee80211_scan_completed(struct ieee80211_hw *hw, bool aborted)
 351 {
 352         struct ieee80211_local *local = hw_to_local(hw);
 353
 354         trace_api_scan_completed(local, aborted);
 355
 356         set_bit(SCAN_COMPLETED, &local->scanning);
 357         if (aborted)
 358                 set_bit(SCAN_ABORTED, &local->scanning);
 359         ieee80211_queue_delayed_work(&local->hw, &local->scan_work, 0);
 360 }
 361 EXPORT_SYMBOL(ieee80211_scan_completed);
 362
 363 static int ieee80211_start_sw_scan(struct ieee80211_local *local)
 364 {
 365         /* Software scan is not supported in multi-channel cases */
 366         if (local->use_chanctx)
 367                 return -EOPNOTSUPP;
 368
 369         /*
 370          * Hardware/driver doesn't support hw_scan, so use software
 371          * scanning instead. First send a nullfunc frame with power save
 372          * bit on so that AP will buffer the frames for us while we are not
 373          * listening, then send probe requests to each channel and wait for
 374          * the responses. After all channels are scanned, tune back to the
 375          * original channel and send a nullfunc frame with power save bit
 376          * off to trigger the AP to send us all the buffered frames.
 377          *
 378          * Note that while local->sw_scanning is true everything else but
 379          * nullfunc frames and probe requests will be dropped in
 380          * ieee80211_tx_h_check_assoc().
 381          */
 382         drv_sw_scan_start(local);
 383
 384         local->leave_oper_channel_time = jiffies;
 385         local->next_scan_state = SCAN_DECISION;
 386         local->scan_channel_idx = 0;
 387
 388         ieee80211_offchannel_stop_vifs(local);
 389
 390         /* ensure nullfunc is transmitted before leaving operating channel */
 391         ieee80211_flush_queues(local, NULL);
 392
 393         ieee80211_configure_filter(local);
 394
 395         /* We need to set power level at maximum rate for scanning. */
 396         ieee80211_hw_config(local, 0);
 397
 398         ieee80211_queue_delayed_work(&local->hw,
 399                                      &local->scan_work, 0);
 400
 401         return 0;
 402 }
 403
 404 static bool ieee80211_can_scan(struct ieee80211_local *local,
 405                                struct ieee80211_sub_if_data *sdata)
 406 {
 407         if (local->radar_detect_enabled)
 408                 return false;
 409
 410         if (!list_empty(&local->roc_list))
 411                 return false;
 412
 413         if (sdata->vif.type == NL80211_IFTYPE_STATION &&
 414             sdata->u.mgd.flags & IEEE80211_STA_CONNECTION_POLL)
 415                 return false;
 416
 417         return true;
 418 }
 419
 420 void ieee80211_run_deferred_scan(struct ieee80211_local *local)
 421 {
 422         lockdep_assert_held(&local->mtx);
 423
 424         if (!local->scan_req || local->scanning)
 425                 return;
 426
 427         if (!ieee80211_can_scan(local,
 428                                 rcu_dereference_protected(
 429                                         local->scan_sdata,
 430                                         lockdep_is_held(&local->mtx))))
 431                 return;
 432
 433         ieee80211_queue_delayed_work(&local->hw, &local->scan_work,
 434                                      round_jiffies_relative(0));
 435 }
 436
 437 static void ieee80211_scan_state_send_probe(struct ieee80211_local *local,
 438                                             unsigned long *next_delay)
 439 {
 440         int i;
 441         struct ieee80211_sub_if_data *sdata;
 442         enum ieee80211_band band = local->hw.conf.chandef.chan->band;
 443         u32 tx_flags;
 444
 445         tx_flags = IEEE80211_TX_INTFL_OFFCHAN_TX_OK;
 446         if (local->scan_req->no_cck)
 447                 tx_flags |= IEEE80211_TX_CTL_NO_CCK_RATE;
 448
 449         sdata = rcu_dereference_protected(local->scan_sdata,
 450                                           lockdep_is_held(&local->mtx));
 451
 452         for (i = 0; i < local->scan_req->n_ssids; i++)
 453                 ieee80211_send_probe_req(
 454                         sdata, NULL,
 455                         local->scan_req->ssids[i].ssid,
 456                         local->scan_req->ssids[i].ssid_len,
 457                         local->scan_req->ie, local->scan_req->ie_len,
 458                         local->scan_req->rates[band], false,
 459                         tx_flags, local->hw.conf.chandef.chan, true);
 460
 461         /*
 462          * After sending probe requests, wait for probe responses
 463          * on the channel.
 464          */
 465         *next_delay = IEEE80211_CHANNEL_TIME;
 466         local->next_scan_state = SCAN_DECISION;
 467 }
 468
 469 static int __ieee80211_start_scan(struct ieee80211_sub_if_data *sdata,
 470                                   struct cfg80211_scan_request *req)
 471 {
 472         struct ieee80211_local *local = sdata->local;
 473         int rc;
 474
 475         lockdep_assert_held(&local->mtx);
 476
 477         if (local->scan_req)
 478                 return -EBUSY;
 479
 480         if (!ieee80211_can_scan(local, sdata)) {
 481                 /* wait for the work to finish/time out */
 482                 local->scan_req = req;
 483                 rcu_assign_pointer(local->scan_sdata, sdata);
 484                 return 0;
 485         }
 486
 487         if (local->ops->hw_scan) {
 488                 u8 *ies;
 489
 490                 local->hw_scan_ies_bufsize = local->scan_ies_len + req->ie_len;
 491
 492                 if (local->hw.flags & IEEE80211_SINGLE_HW_SCAN_ON_ALL_BANDS) {
 493                         int i, n_bands = 0;
 494                         u8 bands_counted = 0;
 495
 496                         for (i = 0; i < req->n_channels; i++) {
 497                                 if (bands_counted & BIT(req->channels[i]->band))
 498                                         continue;
 499                                 bands_counted |= BIT(req->channels[i]->band);
 500                                 n_bands++;
 501                         }
 502
 503                         local->hw_scan_ies_bufsize *= n_bands;
 504                 }
 505
 506                 local->hw_scan_req = kmalloc(
 507                                 sizeof(*local->hw_scan_req) +
 508                                 req->n_channels * sizeof(req->channels[0]) +
 509                                 local->hw_scan_ies_bufsize, GFP_KERNEL);
 510                 if (!local->hw_scan_req)
 511                         return -ENOMEM;
 512
 513                 local->hw_scan_req->req.ssids = req->ssids;
 514                 local->hw_scan_req->req.n_ssids = req->n_ssids;
 515                 ies = (u8 *)local->hw_scan_req +
 516                         sizeof(*local->hw_scan_req) +
 517                         req->n_channels * sizeof(req->channels[0]);
 518                 local->hw_scan_req->req.ie = ies;
 519                 local->hw_scan_req->req.flags = req->flags;
 520
 521                 local->hw_scan_band = 0;
 522
 523                 /*
 524                  * After allocating local->hw_scan_req, we must
 525                  * go through until ieee80211_prep_hw_scan(), so
 526                  * anything that might be changed here and leave
 527                  * this function early must not go after this
 528                  * allocation.
 529                  */
 530         }
 531
 532         local->scan_req = req;
 533         rcu_assign_pointer(local->scan_sdata, sdata);
 534
 535         if (local->ops->hw_scan) {
 536                 __set_bit(SCAN_HW_SCANNING, &local->scanning);
 537         } else if ((req->n_channels == 1) &&
 538                    (req->channels[0] == local->_oper_chandef.chan)) {
 539                 /*
 540                  * If we are scanning only on the operating channel
 541                  * then we do not need to stop normal activities
 542                  */
 543                 unsigned long next_delay;
 544
 545                 __set_bit(SCAN_ONCHANNEL_SCANNING, &local->scanning);
 546
 547                 ieee80211_recalc_idle(local);
 548
 549                 /* Notify driver scan is starting, keep order of operations
 550                  * same as normal software scan, in case that matters. */
 551                 drv_sw_scan_start(local);
 552
 553                 ieee80211_configure_filter(local); /* accept probe-responses */
 554
 555                 /* We need to ensure power level is at max for scanning. */
 556                 ieee80211_hw_config(local, 0);
 557
 558                 if ((req->channels[0]->flags &
 559                      IEEE80211_CHAN_NO_IR) ||
 560                     !local->scan_req->n_ssids) {
 561                         next_delay = IEEE80211_PASSIVE_CHANNEL_TIME;
 562                 } else {
 563                         ieee80211_scan_state_send_probe(local, &next_delay);
 564                         next_delay = IEEE80211_CHANNEL_TIME;
 565                 }
 566
 567                 /* Now, just wait a bit and we are all done! */
 568                 ieee80211_queue_delayed_work(&local->hw, &local->scan_work,
 569                                              next_delay);
 570                 return 0;
 571         } else {
 572                 /* Do normal software scan */
 573                 __set_bit(SCAN_SW_SCANNING, &local->scanning);
 574         }
 575
 576         ieee80211_recalc_idle(local);
 577
 578         if (local->ops->hw_scan) {
 579                 WARN_ON(!ieee80211_prep_hw_scan(local));
 580                 rc = drv_hw_scan(local, sdata, local->hw_scan_req);
 581         } else
 582                 rc = ieee80211_start_sw_scan(local);
 583
 584         if (rc) {
 585                 kfree(local->hw_scan_req);
 586                 local->hw_scan_req = NULL;
 587                 local->scanning = 0;
 588
 589                 ieee80211_recalc_idle(local);
 590
 591                 local->scan_req = NULL;
 592                 RCU_INIT_POINTER(local->scan_sdata, NULL);
 593         }
 594
 595         return rc;
 596 }
 597
 598 static unsigned long
 599 ieee80211_scan_get_channel_time(struct ieee80211_channel *chan)
 600 {
 601         /*
 602          * TODO: channel switching also consumes quite some time,
 603          * add that delay as well to get a better estimation
 604          */
 605         if (chan->flags & IEEE80211_CHAN_NO_IR)
 606                 return IEEE80211_PASSIVE_CHANNEL_TIME;
 607         return IEEE80211_PROBE_DELAY + IEEE80211_CHANNEL_TIME;
 608 }
 609
 610 static void ieee80211_scan_state_decision(struct ieee80211_local *local,
 611                                           unsigned long *next_delay)
 612 {
 613         bool associated = false;
 614         bool tx_empty = true;
 615         bool bad_latency;
 616         struct ieee80211_sub_if_data *sdata;
 617         struct ieee80211_channel *next_chan;
 618         enum mac80211_scan_state next_scan_state;
 619
 620         /*
 621          * check if at least one STA interface is associated,
 622          * check if at least one STA interface has pending tx frames
 623          * and grab the lowest used beacon interval
 624          */
 625         mutex_lock(&local->iflist_mtx);
 626         list_for_each_entry(sdata, &local->interfaces, list) {
 627                 if (!ieee80211_sdata_running(sdata))
 628                         continue;
 629
 630                 if (sdata->vif.type == NL80211_IFTYPE_STATION) {
 631                         if (sdata->u.mgd.associated) {
 632                                 associated = true;
 633
 634                                 if (!qdisc_all_tx_empty(sdata->dev)) {
 635                                         tx_empty = false;
 636                                         break;
 637                                 }
 638                         }
 639                 }
 640         }
 641         mutex_unlock(&local->iflist_mtx);
 642
 643         next_chan = local->scan_req->channels[local->scan_channel_idx];
 644
 645         /*
 646          * we're currently scanning a different channel, let's
 647          * see if we can scan another channel without interfering
 648          * with the current traffic situation.
 649          *
 650          * Keep good latency, do not stay off-channel more than 125 ms.
 651          */
 652
 653         bad_latency = time_after(jiffies +
 654                                  ieee80211_scan_get_channel_time(next_chan),
 655                                  local->leave_oper_channel_time + HZ / 8);
 656
 657         if (associated && !tx_empty) {
 658                 if (local->scan_req->flags & NL80211_SCAN_FLAG_LOW_PRIORITY)
 659                         next_scan_state = SCAN_ABORT;
 660                 else
 661                         next_scan_state = SCAN_SUSPEND;
 662         } else if (associated && bad_latency) {
 663                 next_scan_state = SCAN_SUSPEND;
 664         } else {
 665                 next_scan_state = SCAN_SET_CHANNEL;
 666         }
 667
 668         local->next_scan_state = next_scan_state;
 669
 670         *next_delay = 0;
 671 }
 672
 673 static void ieee80211_scan_state_set_channel(struct ieee80211_local *local,
 674                                              unsigned long *next_delay)
 675 {
 676         int skip;
 677         struct ieee80211_channel *chan;
 678         enum nl80211_bss_scan_width oper_scan_width;
 679
 680         skip = 0;
 681         chan = local->scan_req->channels[local->scan_channel_idx];
 682
 683         local->scan_chandef.chan = chan;
 684         local->scan_chandef.center_freq1 = chan->center_freq;
 685         local->scan_chandef.center_freq2 = 0;
 686         switch (local->scan_req->scan_width) {
 687         case NL80211_BSS_CHAN_WIDTH_5:
 688                 local->scan_chandef.width = NL80211_CHAN_WIDTH_5;
 689                 break;
 690         case NL80211_BSS_CHAN_WIDTH_10:
 691                 local->scan_chandef.width = NL80211_CHAN_WIDTH_10;
 692                 break;
 693         case NL80211_BSS_CHAN_WIDTH_20:
 694                 /* If scanning on oper channel, use whatever channel-type
 695                  * is currently in use.
 696                  */
 697                 oper_scan_width = cfg80211_chandef_to_scan_width(
 698                                         &local->_oper_chandef);
 699                 if (chan == local->_oper_chandef.chan &&
 700                     oper_scan_width == local->scan_req->scan_width)
 701                         local->scan_chandef = local->_oper_chandef;
 702                 else
 703                         local->scan_chandef.width = NL80211_CHAN_WIDTH_20_NOHT;
 704                 break;
 705         }
 706
 707         if (ieee80211_hw_config(local, IEEE80211_CONF_CHANGE_CHANNEL))
 708                 skip = 1;
 709
 710         /* advance state machine to next channel/band */
 711         local->scan_channel_idx++;
 712
 713         if (skip) {
 714                 /* if we skip this channel return to the decision state */
 715                 local->next_scan_state = SCAN_DECISION;
 716                 return;
 717         }
 718
 719         /*
 720          * Probe delay is used to update the NAV, cf. 11.1.3.2.2
 721          * (which unfortunately doesn't say _why_ step a) is done,
 722          * but it waits for the probe delay or until a frame is
 723          * received - and the received frame would update the NAV).
 724          * For now, we do not support waiting until a frame is
 725          * received.
 726          *
 727          * In any case, it is not necessary for a passive scan.
 728          */
 729         if (chan->flags & IEEE80211_CHAN_NO_IR ||
 730             !local->scan_req->n_ssids) {
 731                 *next_delay = IEEE80211_PASSIVE_CHANNEL_TIME;
 732                 local->next_scan_state = SCAN_DECISION;
 733                 return;
 734         }
 735
 736         /* active scan, send probes */
 737         *next_delay = IEEE80211_PROBE_DELAY;
 738         local->next_scan_state = SCAN_SEND_PROBE;
 739 }
 740
 741 static void ieee80211_scan_state_suspend(struct ieee80211_local *local,
 742                                          unsigned long *next_delay)
 743 {
 744         /* switch back to the operating channel */
 745         local->scan_chandef.chan = NULL;
 746         ieee80211_hw_config(local, IEEE80211_CONF_CHANGE_CHANNEL);
 747
 748         /* disable PS */
 749         ieee80211_offchannel_return(local);
 750
 751         *next_delay = HZ / 5;
 752         /* afterwards, resume scan & go to next channel */
 753         local->next_scan_state = SCAN_RESUME;
 754 }
 755
 756 static void ieee80211_scan_state_resume(struct ieee80211_local *local,
 757                                         unsigned long *next_delay)
 758 {
 759         ieee80211_offchannel_stop_vifs(local);
 760
 761         if (local->ops->flush) {
 762                 ieee80211_flush_queues(local, NULL);
 763                 *next_delay = 0;
 764         } else
 765                 *next_delay = HZ / 10;
 766
 767         /* remember when we left the operating channel */
 768         local->leave_oper_channel_time = jiffies;
 769
 770         /* advance to the next channel to be scanned */
 771         local->next_scan_state = SCAN_SET_CHANNEL;
 772 }
 773
 774 void ieee80211_scan_work(struct work_struct *work)
 775 {
 776         struct ieee80211_local *local =
 777                 container_of(work, struct ieee80211_local, scan_work.work);
 778         struct ieee80211_sub_if_data *sdata;
 779         unsigned long next_delay = 0;
 780         bool aborted;
 781
 782         mutex_lock(&local->mtx);
 783
 784         sdata = rcu_dereference_protected(local->scan_sdata,
 785                                           lockdep_is_held(&local->mtx));
 786
 787         /* When scanning on-channel, the first-callback means completed. */
 788         if (test_bit(SCAN_ONCHANNEL_SCANNING, &local->scanning)) {
 789                 aborted = test_and_clear_bit(SCAN_ABORTED, &local->scanning);
 790                 goto out_complete;
 791         }
 792
 793         if (test_and_clear_bit(SCAN_COMPLETED, &local->scanning)) {
 794                 aborted = test_and_clear_bit(SCAN_ABORTED, &local->scanning);
 795                 goto out_complete;
 796         }
 797
 798         if (!sdata || !local->scan_req)
 799                 goto out;
 800
 801         if (local->scan_req && !local->scanning) {
 802                 struct cfg80211_scan_request *req = local->scan_req;
 803                 int rc;
 804
 805                 local->scan_req = NULL;
 806                 RCU_INIT_POINTER(local->scan_sdata, NULL);
 807
 808                 rc = __ieee80211_start_scan(sdata, req);
 809                 if (rc) {
 810                         /* need to complete scan in cfg80211 */
 811                         local->scan_req = req;
 812                         aborted = true;
 813                         goto out_complete;
 814                 } else
 815                         goto out;
 816         }
 817
 818         /*
 819          * as long as no delay is required advance immediately
 820          * without scheduling a new work
 821          */
 822         do {
 823                 if (!ieee80211_sdata_running(sdata)) {
 824                         aborted = true;
 825                         goto out_complete;
 826                 }
 827
 828                 switch (local->next_scan_state) {
 829                 case SCAN_DECISION:
 830                         /* if no more bands/channels left, complete scan */
 831                         if (local->scan_channel_idx >= local->scan_req->n_channels) {
 832                                 aborted = false;
 833                                 goto out_complete;
 834                         }
 835                         ieee80211_scan_state_decision(local, &next_delay);
 836                         break;
 837                 case SCAN_SET_CHANNEL:
 838                         ieee80211_scan_state_set_channel(local, &next_delay);
 839                         break;
 840                 case SCAN_SEND_PROBE:
 841                         ieee80211_scan_state_send_probe(local, &next_delay);
 842                         break;
 843                 case SCAN_SUSPEND:
 844                         ieee80211_scan_state_suspend(local, &next_delay);
 845                         break;
 846                 case SCAN_RESUME:
 847                         ieee80211_scan_state_resume(local, &next_delay);
 848                         break;
 849                 case SCAN_ABORT:
 850                         aborted = true;
 851                         goto out_complete;
 852                 }
 853         } while (next_delay == 0);
 854
 855         ieee80211_queue_delayed_work(&local->hw, &local->scan_work, next_delay);
 856         goto out;
 857
 858 out_complete:
 859         __ieee80211_scan_completed(&local->hw, aborted);
 860 out:
 861         mutex_unlock(&local->mtx);
 862 }
 863
 864 int ieee80211_request_scan(struct ieee80211_sub_if_data *sdata,
 865                            struct cfg80211_scan_request *req)
 866 {
 867         int res;
 868
 869         mutex_lock(&sdata->local->mtx);
 870         res = __ieee80211_start_scan(sdata, req);
 871         mutex_unlock(&sdata->local->mtx);
 872
 873         return res;
 874 }
 875
 876 int ieee80211_request_ibss_scan(struct ieee80211_sub_if_data *sdata,
 877                                 const u8 *ssid, u8 ssid_len,
 878                                 struct ieee80211_channel *chan,
 879                                 enum nl80211_bss_scan_width scan_width)
 880 {
 881         struct ieee80211_local *local = sdata->local;
 882         int ret = -EBUSY;
 883         enum ieee80211_band band;
 884
 885         mutex_lock(&local->mtx);
 886
 887         /* busy scanning */
 888         if (local->scan_req)
 889                 goto unlock;
 890
 891         /* fill internal scan request */
 892         if (!chan) {
 893                 int i, max_n;
 894                 int n_ch = 0;
 895
 896                 for (band = 0; band < IEEE80211_NUM_BANDS; band++) {
 897                         if (!local->hw.wiphy->bands[band])
 898                                 continue;
 899
 900                         max_n = local->hw.wiphy->bands[band]->n_channels;
 901                         for (i = 0; i < max_n; i++) {
 902                                 struct ieee80211_channel *tmp_ch =
 903                                     &local->hw.wiphy->bands[band]->channels[i];
 904
 905                                 if (tmp_ch->flags & (IEEE80211_CHAN_NO_IR |
 906                                                      IEEE80211_CHAN_DISABLED))
 907                                         continue;
 908
 909                                 local->int_scan_req->channels[n_ch] = tmp_ch;
 910                                 n_ch++;
 911                         }
 912                 }
 913
 914                 if (WARN_ON_ONCE(n_ch == 0))
 915                         goto unlock;
 916
 917                 local->int_scan_req->n_channels = n_ch;
 918         } else {
 919                 if (WARN_ON_ONCE(chan->flags & (IEEE80211_CHAN_NO_IR |
 920                                                 IEEE80211_CHAN_DISABLED)))
 921                         goto unlock;
 922
 923                 local->int_scan_req->channels[0] = chan;
 924                 local->int_scan_req->n_channels = 1;
 925         }
 926
 927         local->int_scan_req->ssids = &local->scan_ssid;
 928         local->int_scan_req->n_ssids = 1;
 929         local->int_scan_req->scan_width = scan_width;
 930         memcpy(local->int_scan_req->ssids[0].ssid, ssid, IEEE80211_MAX_SSID_LEN);
 931         local->int_scan_req->ssids[0].ssid_len = ssid_len;
 932
 933         ret = __ieee80211_start_scan(sdata, sdata->local->int_scan_req);
 934  unlock:
 935         mutex_unlock(&local->mtx);
 936         return ret;
 937 }
 938
 939 /*
 940  * Only call this function when a scan can't be queued -- under RTNL.
 941  */
 942 void ieee80211_scan_cancel(struct ieee80211_local *local)
 943 {
 944         /*
 945          * We are canceling software scan, or deferred scan that was not
 946          * yet really started (see __ieee80211_start_scan ).
 947          *
 948          * Regarding hardware scan:
 949          * - we can not call  __ieee80211_scan_completed() as when
 950          *   SCAN_HW_SCANNING bit is set this function change
 951          *   local->hw_scan_req to operate on 5G band, what race with
 952          *   driver which can use local->hw_scan_req
 953          *
 954          * - we can not cancel scan_work since driver can schedule it
 955          *   by ieee80211_scan_completed(..., true) to finish scan
 956          *
 957          * Hence we only call the cancel_hw_scan() callback, but the low-level
 958          * driver is still responsible for calling ieee80211_scan_completed()
 959          * after the scan was completed/aborted.
 960          */
 961
 962         mutex_lock(&local->mtx);
 963         if (!local->scan_req)
 964                 goto out;
 965
 966         /*
 967          * We have a scan running and the driver already reported completion,
 968          * but the worker hasn't run yet or is stuck on the mutex - mark it as
 969          * cancelled.
 970          */
 971         if (test_bit(SCAN_HW_SCANNING, &local->scanning) &&
 972             test_bit(SCAN_COMPLETED, &local->scanning)) {
 973                 set_bit(SCAN_HW_CANCELLED, &local->scanning);
 974                 goto out;
 975         }
 976
 977         if (test_bit(SCAN_HW_SCANNING, &local->scanning)) {
 978                 /*
 979                  * Make sure that __ieee80211_scan_completed doesn't trigger a
 980                  * scan on another band.
 981                  */
 982                 set_bit(SCAN_HW_CANCELLED, &local->scanning);
 983                 if (local->ops->cancel_hw_scan)
 984                         drv_cancel_hw_scan(local,
 985                                 rcu_dereference_protected(local->scan_sdata,
 986                                                 lockdep_is_held(&local->mtx)));
 987                 goto out;
 988         }
 989
 990         /*
 991          * If the work is currently running, it must be blocked on
 992          * the mutex, but we'll set scan_sdata = NULL and it'll
 993          * simply exit once it acquires the mutex.
 994          */
 995         cancel_delayed_work(&local->scan_work);
 996         /* and clean up */
 997         __ieee80211_scan_completed(&local->hw, true);
 998 out:
 999         mutex_unlock(&local->mtx);
1000 }
1001
1002 int __ieee80211_request_sched_scan_start(struct ieee80211_sub_if_data *sdata,
1003                                         struct cfg80211_sched_scan_request *req)
1004 {
1005         struct ieee80211_local *local = sdata->local;
1006         struct ieee80211_scan_ies sched_scan_ies = {};
1007         struct cfg80211_chan_def chandef;
1008         int ret, i, iebufsz, num_bands = 0;
1009         u32 rate_masks[IEEE80211_NUM_BANDS] = {};
1010         u8 bands_used = 0;
1011         u8 *ie;
1012         size_t len;
1013
1014         iebufsz = local->scan_ies_len + req->ie_len;
1015
1016         lockdep_assert_held(&local->mtx);
1017
1018         if (!local->ops->sched_scan_start)
1019                 return -ENOTSUPP;
1020
1021         for (i = 0; i < IEEE80211_NUM_BANDS; i++) {
1022                 if (local->hw.wiphy->bands[i]) {
1023                         bands_used |= BIT(i);
1024                         rate_masks[i] = (u32) -1;
1025                         num_bands++;
1026                 }
1027         }
1028
1029         ie = kzalloc(num_bands * iebufsz, GFP_KERNEL);
1030         if (!ie) {
1031                 ret = -ENOMEM;
1032                 goto out;
1033         }
1034
1035         ieee80211_prepare_scan_chandef(&chandef, req->scan_width);
1036
1037         len = ieee80211_build_preq_ies(local, ie, num_bands * iebufsz,
1038                                        &sched_scan_ies, req->ie,
1039                                        req->ie_len, bands_used,
1040                                        rate_masks, &chandef);
1041
1042         ret = drv_sched_scan_start(local, sdata, req, &sched_scan_ies);
1043         if (ret == 0) {
1044                 rcu_assign_pointer(local->sched_scan_sdata, sdata);
1045                 local->sched_scan_req = req;
1046         }
1047
1048         kfree(ie);
1049
1050 out:
1051         if (ret) {
1052                 /* Clean in case of failure after HW restart or upon resume. */
1053                 RCU_INIT_POINTER(local->sched_scan_sdata, NULL);
1054                 local->sched_scan_req = NULL;
1055         }
1056
1057         return ret;
1058 }
1059
1060 int ieee80211_request_sched_scan_start(struct ieee80211_sub_if_data *sdata,
1061                                        struct cfg80211_sched_scan_request *req)
1062 {
1063         struct ieee80211_local *local = sdata->local;
1064         int ret;
1065
1066         mutex_lock(&local->mtx);
1067
1068         if (rcu_access_pointer(local->sched_scan_sdata)) {
1069                 mutex_unlock(&local->mtx);
1070                 return -EBUSY;
1071         }
1072
1073         ret = __ieee80211_request_sched_scan_start(sdata, req);
1074
1075         mutex_unlock(&local->mtx);
1076         return ret;
1077 }
1078
1079 int ieee80211_request_sched_scan_stop(struct ieee80211_sub_if_data *sdata)
1080 {
1081         struct ieee80211_local *local = sdata->local;
1082         int ret = 0;
1083
1084         mutex_lock(&local->mtx);
1085
1086         if (!local->ops->sched_scan_stop) {
1087                 ret = -ENOTSUPP;
1088                 goto out;
1089         }
1090
1091         /* We don't want to restart sched scan anymore. */
1092         local->sched_scan_req = NULL;
1093
1094         if (rcu_access_pointer(local->sched_scan_sdata)) {
1095                 ret = drv_sched_scan_stop(local, sdata);
1096                 if (!ret)
1097                         rcu_assign_pointer(local->sched_scan_sdata, NULL);
1098         }
1099 out:
1100         mutex_unlock(&local->mtx);
1101
1102         return ret;
1103 }
1104
1105 void ieee80211_sched_scan_results(struct ieee80211_hw *hw)
1106 {
1107         struct ieee80211_local *local = hw_to_local(hw);
1108
1109         trace_api_sched_scan_results(local);
1110
1111         cfg80211_sched_scan_results(hw->wiphy);
1112 }
1113 EXPORT_SYMBOL(ieee80211_sched_scan_results);
1114
1115 void ieee80211_sched_scan_end(struct ieee80211_local *local)
1116 {
1117         mutex_lock(&local->mtx);
1118
1119         if (!rcu_access_pointer(local->sched_scan_sdata)) {
1120                 mutex_unlock(&local->mtx);
1121                 return;
1122         }
1123
1124         RCU_INIT_POINTER(local->sched_scan_sdata, NULL);
1125
1126         /* If sched scan was aborted by the driver. */
1127         local->sched_scan_req = NULL;
1128
1129         mutex_unlock(&local->mtx);
1130
1131         cfg80211_sched_scan_stopped(local->hw.wiphy);
1132 }
1133
1134 void ieee80211_sched_scan_stopped_work(struct work_struct *work)
1135 {
1136         struct ieee80211_local *local =
1137                 container_of(work, struct ieee80211_local,
1138                              sched_scan_stopped_work);
1139
1140         ieee80211_sched_scan_end(local);
1141 }
1142
1143 void ieee80211_sched_scan_stopped(struct ieee80211_hw *hw)
1144 {
1145         struct ieee80211_local *local = hw_to_local(hw);
1146
1147         trace_api_sched_scan_stopped(local);
1148
1149         schedule_work(&local->sched_scan_stopped_work);
1150 }
1151 EXPORT_SYMBOL(ieee80211_sched_scan_stopped);