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 {
 276         struct ieee80211_local *local = hw_to_local(hw);
 277         bool hw_scan = local->ops->hw_scan;
 278         bool was_scanning = local->scanning;
 279
 280         lockdep_assert_held(&local->mtx);
 281
 282         /*
 283          * It's ok to abort a not-yet-running scan (that
 284          * we have one at all will be verified by checking
 285          * local->scan_req next), but not to complete it
 286          * successfully.
 287          */
 288         if (WARN_ON(!local->scanning && !aborted))
 289                 aborted = true;
 290
 291         if (WARN_ON(!local->scan_req))
 292                 return;
 293
 294         if (hw_scan && !aborted && ieee80211_prep_hw_scan(local)) {
 295                 int rc;
 296
 297                 rc = drv_hw_scan(local,
 298                         rcu_dereference_protected(local->scan_sdata,
 299                                                   lockdep_is_held(&local->mtx)),
 300                         local->hw_scan_req);
 301
 302                 if (rc == 0)
 303                         return;
 304         }
 305
 306         kfree(local->hw_scan_req);
 307         local->hw_scan_req = NULL;
 308
 309         if (local->scan_req != local->int_scan_req)
 310                 cfg80211_scan_done(local->scan_req, aborted);
 311         local->scan_req = NULL;
 312         RCU_INIT_POINTER(local->scan_sdata, NULL);
 313
 314         local->scanning = 0;
 315         local->scan_chandef.chan = NULL;
 316
 317         /* Set power back to normal operating levels. */
 318         ieee80211_hw_config(local, 0);
 319
 320         if (!hw_scan) {
 321                 ieee80211_configure_filter(local);
 322                 drv_sw_scan_complete(local);
 323                 ieee80211_offchannel_return(local);
 324         }
 325
 326         ieee80211_recalc_idle(local);
 327
 328         ieee80211_mlme_notify_scan_completed(local);
 329         ieee80211_ibss_notify_scan_completed(local);
 330         ieee80211_mesh_notify_scan_completed(local);
 331         if (was_scanning)
 332                 ieee80211_start_next_roc(local);
 333 }
 334
 335 void ieee80211_scan_completed(struct ieee80211_hw *hw, bool aborted)
 336 {
 337         struct ieee80211_local *local = hw_to_local(hw);
 338
 339         trace_api_scan_completed(local, aborted);
 340
 341         set_bit(SCAN_COMPLETED, &local->scanning);
 342         if (aborted)
 343                 set_bit(SCAN_ABORTED, &local->scanning);
 344         ieee80211_queue_delayed_work(&local->hw, &local->scan_work, 0);
 345 }
 346 EXPORT_SYMBOL(ieee80211_scan_completed);
 347
 348 static int ieee80211_start_sw_scan(struct ieee80211_local *local)
 349 {
 350         /* Software scan is not supported in multi-channel cases */
 351         if (local->use_chanctx)
 352                 return -EOPNOTSUPP;
 353
 354         /*
 355          * Hardware/driver doesn't support hw_scan, so use software
 356          * scanning instead. First send a nullfunc frame with power save
 357          * bit on so that AP will buffer the frames for us while we are not
 358          * listening, then send probe requests to each channel and wait for
 359          * the responses. After all channels are scanned, tune back to the
 360          * original channel and send a nullfunc frame with power save bit
 361          * off to trigger the AP to send us all the buffered frames.
 362          *
 363          * Note that while local->sw_scanning is true everything else but
 364          * nullfunc frames and probe requests will be dropped in
 365          * ieee80211_tx_h_check_assoc().
 366          */
 367         drv_sw_scan_start(local);
 368
 369         local->leave_oper_channel_time = jiffies;
 370         local->next_scan_state = SCAN_DECISION;
 371         local->scan_channel_idx = 0;
 372
 373         ieee80211_offchannel_stop_vifs(local);
 374
 375         /* ensure nullfunc is transmitted before leaving operating channel */
 376         ieee80211_flush_queues(local, NULL);
 377
 378         ieee80211_configure_filter(local);
 379
 380         /* We need to set power level at maximum rate for scanning. */
 381         ieee80211_hw_config(local, 0);
 382
 383         ieee80211_queue_delayed_work(&local->hw,
 384                                      &local->scan_work, 0);
 385
 386         return 0;
 387 }
 388
 389 static bool ieee80211_can_scan(struct ieee80211_local *local,
 390                                struct ieee80211_sub_if_data *sdata)
 391 {
 392         if (local->radar_detect_enabled)
 393                 return false;
 394
 395         if (!list_empty(&local->roc_list))
 396                 return false;
 397
 398         if (sdata->vif.type == NL80211_IFTYPE_STATION &&
 399             sdata->u.mgd.flags & IEEE80211_STA_CONNECTION_POLL)
 400                 return false;
 401
 402         return true;
 403 }
 404
 405 void ieee80211_run_deferred_scan(struct ieee80211_local *local)
 406 {
 407         lockdep_assert_held(&local->mtx);
 408
 409         if (!local->scan_req || local->scanning)
 410                 return;
 411
 412         if (!ieee80211_can_scan(local,
 413                                 rcu_dereference_protected(
 414                                         local->scan_sdata,
 415                                         lockdep_is_held(&local->mtx))))
 416                 return;
 417
 418         ieee80211_queue_delayed_work(&local->hw, &local->scan_work,
 419                                      round_jiffies_relative(0));
 420 }
 421
 422 static void ieee80211_scan_state_send_probe(struct ieee80211_local *local,
 423                                             unsigned long *next_delay)
 424 {
 425         int i;
 426         struct ieee80211_sub_if_data *sdata;
 427         enum ieee80211_band band = local->hw.conf.chandef.chan->band;
 428         u32 tx_flags;
 429
 430         tx_flags = IEEE80211_TX_INTFL_OFFCHAN_TX_OK;
 431         if (local->scan_req->no_cck)
 432                 tx_flags |= IEEE80211_TX_CTL_NO_CCK_RATE;
 433
 434         sdata = rcu_dereference_protected(local->scan_sdata,
 435                                           lockdep_is_held(&local->mtx));
 436
 437         for (i = 0; i < local->scan_req->n_ssids; i++)
 438                 ieee80211_send_probe_req(
 439                         sdata, NULL,
 440                         local->scan_req->ssids[i].ssid,
 441                         local->scan_req->ssids[i].ssid_len,
 442                         local->scan_req->ie, local->scan_req->ie_len,
 443                         local->scan_req->rates[band], false,
 444                         tx_flags, local->hw.conf.chandef.chan, true);
 445
 446         /*
 447          * After sending probe requests, wait for probe responses
 448          * on the channel.
 449          */
 450         *next_delay = IEEE80211_CHANNEL_TIME;
 451         local->next_scan_state = SCAN_DECISION;
 452 }
 453
 454 static int __ieee80211_start_scan(struct ieee80211_sub_if_data *sdata,
 455                                   struct cfg80211_scan_request *req)
 456 {
 457         struct ieee80211_local *local = sdata->local;
 458         int rc;
 459
 460         lockdep_assert_held(&local->mtx);
 461
 462         if (local->scan_req)
 463                 return -EBUSY;
 464
 465         if (!ieee80211_can_scan(local, sdata)) {
 466                 /* wait for the work to finish/time out */
 467                 local->scan_req = req;
 468                 rcu_assign_pointer(local->scan_sdata, sdata);
 469                 return 0;
 470         }
 471
 472         if (local->ops->hw_scan) {
 473                 u8 *ies;
 474
 475                 local->hw_scan_ies_bufsize = local->scan_ies_len + req->ie_len;
 476                 local->hw_scan_req = kmalloc(
 477                                 sizeof(*local->hw_scan_req) +
 478                                 req->n_channels * sizeof(req->channels[0]) +
 479                                 local->hw_scan_ies_bufsize, GFP_KERNEL);
 480                 if (!local->hw_scan_req)
 481                         return -ENOMEM;
 482
 483                 local->hw_scan_req->ssids = req->ssids;
 484                 local->hw_scan_req->n_ssids = req->n_ssids;
 485                 ies = (u8 *)local->hw_scan_req +
 486                         sizeof(*local->hw_scan_req) +
 487                         req->n_channels * sizeof(req->channels[0]);
 488                 local->hw_scan_req->ie = ies;
 489                 local->hw_scan_req->flags = req->flags;
 490
 491                 local->hw_scan_band = 0;
 492
 493                 /*
 494                  * After allocating local->hw_scan_req, we must
 495                  * go through until ieee80211_prep_hw_scan(), so
 496                  * anything that might be changed here and leave
 497                  * this function early must not go after this
 498                  * allocation.
 499                  */
 500         }
 501
 502         local->scan_req = req;
 503         rcu_assign_pointer(local->scan_sdata, sdata);
 504
 505         if (local->ops->hw_scan) {
 506                 __set_bit(SCAN_HW_SCANNING, &local->scanning);
 507         } else if ((req->n_channels == 1) &&
 508                    (req->channels[0] == local->_oper_chandef.chan)) {
 509                 /*
 510                  * If we are scanning only on the operating channel
 511                  * then we do not need to stop normal activities
 512                  */
 513                 unsigned long next_delay;
 514
 515                 __set_bit(SCAN_ONCHANNEL_SCANNING, &local->scanning);
 516
 517                 ieee80211_recalc_idle(local);
 518
 519                 /* Notify driver scan is starting, keep order of operations
 520                  * same as normal software scan, in case that matters. */
 521                 drv_sw_scan_start(local);
 522
 523                 ieee80211_configure_filter(local); /* accept probe-responses */
 524
 525                 /* We need to ensure power level is at max for scanning. */
 526                 ieee80211_hw_config(local, 0);
 527
 528                 if ((req->channels[0]->flags &
 529                      IEEE80211_CHAN_NO_IR) ||
 530                     !local->scan_req->n_ssids) {
 531                         next_delay = IEEE80211_PASSIVE_CHANNEL_TIME;
 532                 } else {
 533                         ieee80211_scan_state_send_probe(local, &next_delay);
 534                         next_delay = IEEE80211_CHANNEL_TIME;
 535                 }
 536
 537                 /* Now, just wait a bit and we are all done! */
 538                 ieee80211_queue_delayed_work(&local->hw, &local->scan_work,
 539                                              next_delay);
 540                 return 0;
 541         } else {
 542                 /* Do normal software scan */
 543                 __set_bit(SCAN_SW_SCANNING, &local->scanning);
 544         }
 545
 546         ieee80211_recalc_idle(local);
 547
 548         if (local->ops->hw_scan) {
 549                 WARN_ON(!ieee80211_prep_hw_scan(local));
 550                 rc = drv_hw_scan(local, sdata, local->hw_scan_req);
 551         } else
 552                 rc = ieee80211_start_sw_scan(local);
 553
 554         if (rc) {
 555                 kfree(local->hw_scan_req);
 556                 local->hw_scan_req = NULL;
 557                 local->scanning = 0;
 558
 559                 ieee80211_recalc_idle(local);
 560
 561                 local->scan_req = NULL;
 562                 RCU_INIT_POINTER(local->scan_sdata, NULL);
 563         }
 564
 565         return rc;
 566 }
 567
 568 static unsigned long
 569 ieee80211_scan_get_channel_time(struct ieee80211_channel *chan)
 570 {
 571         /*
 572          * TODO: channel switching also consumes quite some time,
 573          * add that delay as well to get a better estimation
 574          */
 575         if (chan->flags & IEEE80211_CHAN_NO_IR)
 576                 return IEEE80211_PASSIVE_CHANNEL_TIME;
 577         return IEEE80211_PROBE_DELAY + IEEE80211_CHANNEL_TIME;
 578 }
 579
 580 static void ieee80211_scan_state_decision(struct ieee80211_local *local,
 581                                           unsigned long *next_delay)
 582 {
 583         bool associated = false;
 584         bool tx_empty = true;
 585         bool bad_latency;
 586         struct ieee80211_sub_if_data *sdata;
 587         struct ieee80211_channel *next_chan;
 588         enum mac80211_scan_state next_scan_state;
 589
 590         /*
 591          * check if at least one STA interface is associated,
 592          * check if at least one STA interface has pending tx frames
 593          * and grab the lowest used beacon interval
 594          */
 595         mutex_lock(&local->iflist_mtx);
 596         list_for_each_entry(sdata, &local->interfaces, list) {
 597                 if (!ieee80211_sdata_running(sdata))
 598                         continue;
 599
 600                 if (sdata->vif.type == NL80211_IFTYPE_STATION) {
 601                         if (sdata->u.mgd.associated) {
 602                                 associated = true;
 603
 604                                 if (!qdisc_all_tx_empty(sdata->dev)) {
 605                                         tx_empty = false;
 606                                         break;
 607                                 }
 608                         }
 609                 }
 610         }
 611         mutex_unlock(&local->iflist_mtx);
 612
 613         next_chan = local->scan_req->channels[local->scan_channel_idx];
 614
 615         /*
 616          * we're currently scanning a different channel, let's
 617          * see if we can scan another channel without interfering
 618          * with the current traffic situation.
 619          *
 620          * Keep good latency, do not stay off-channel more than 125 ms.
 621          */
 622
 623         bad_latency = time_after(jiffies +
 624                                  ieee80211_scan_get_channel_time(next_chan),
 625                                  local->leave_oper_channel_time + HZ / 8);
 626
 627         if (associated && !tx_empty) {
 628                 if (local->scan_req->flags & NL80211_SCAN_FLAG_LOW_PRIORITY)
 629                         next_scan_state = SCAN_ABORT;
 630                 else
 631                         next_scan_state = SCAN_SUSPEND;
 632         } else if (associated && bad_latency) {
 633                 next_scan_state = SCAN_SUSPEND;
 634         } else {
 635                 next_scan_state = SCAN_SET_CHANNEL;
 636         }
 637
 638         local->next_scan_state = next_scan_state;
 639
 640         *next_delay = 0;
 641 }
 642
 643 static void ieee80211_scan_state_set_channel(struct ieee80211_local *local,
 644                                              unsigned long *next_delay)
 645 {
 646         int skip;
 647         struct ieee80211_channel *chan;
 648         enum nl80211_bss_scan_width oper_scan_width;
 649
 650         skip = 0;
 651         chan = local->scan_req->channels[local->scan_channel_idx];
 652
 653         local->scan_chandef.chan = chan;
 654         local->scan_chandef.center_freq1 = chan->center_freq;
 655         local->scan_chandef.center_freq2 = 0;
 656         switch (local->scan_req->scan_width) {
 657         case NL80211_BSS_CHAN_WIDTH_5:
 658                 local->scan_chandef.width = NL80211_CHAN_WIDTH_5;
 659                 break;
 660         case NL80211_BSS_CHAN_WIDTH_10:
 661                 local->scan_chandef.width = NL80211_CHAN_WIDTH_10;
 662                 break;
 663         case NL80211_BSS_CHAN_WIDTH_20:
 664                 /* If scanning on oper channel, use whatever channel-type
 665                  * is currently in use.
 666                  */
 667                 oper_scan_width = cfg80211_chandef_to_scan_width(
 668                                         &local->_oper_chandef);
 669                 if (chan == local->_oper_chandef.chan &&
 670                     oper_scan_width == local->scan_req->scan_width)
 671                         local->scan_chandef = local->_oper_chandef;
 672                 else
 673                         local->scan_chandef.width = NL80211_CHAN_WIDTH_20_NOHT;
 674                 break;
 675         }
 676
 677         if (ieee80211_hw_config(local, IEEE80211_CONF_CHANGE_CHANNEL))
 678                 skip = 1;
 679
 680         /* advance state machine to next channel/band */
 681         local->scan_channel_idx++;
 682
 683         if (skip) {
 684                 /* if we skip this channel return to the decision state */
 685                 local->next_scan_state = SCAN_DECISION;
 686                 return;
 687         }
 688
 689         /*
 690          * Probe delay is used to update the NAV, cf. 11.1.3.2.2
 691          * (which unfortunately doesn't say _why_ step a) is done,
 692          * but it waits for the probe delay or until a frame is
 693          * received - and the received frame would update the NAV).
 694          * For now, we do not support waiting until a frame is
 695          * received.
 696          *
 697          * In any case, it is not necessary for a passive scan.
 698          */
 699         if (chan->flags & IEEE80211_CHAN_NO_IR ||
 700             !local->scan_req->n_ssids) {
 701                 *next_delay = IEEE80211_PASSIVE_CHANNEL_TIME;
 702                 local->next_scan_state = SCAN_DECISION;
 703                 return;
 704         }
 705
 706         /* active scan, send probes */
 707         *next_delay = IEEE80211_PROBE_DELAY;
 708         local->next_scan_state = SCAN_SEND_PROBE;
 709 }
 710
 711 static void ieee80211_scan_state_suspend(struct ieee80211_local *local,
 712                                          unsigned long *next_delay)
 713 {
 714         /* switch back to the operating channel */
 715         local->scan_chandef.chan = NULL;
 716         ieee80211_hw_config(local, IEEE80211_CONF_CHANGE_CHANNEL);
 717
 718         /* disable PS */
 719         ieee80211_offchannel_return(local);
 720
 721         *next_delay = HZ / 5;
 722         /* afterwards, resume scan & go to next channel */
 723         local->next_scan_state = SCAN_RESUME;
 724 }
 725
 726 static void ieee80211_scan_state_resume(struct ieee80211_local *local,
 727                                         unsigned long *next_delay)
 728 {
 729         ieee80211_offchannel_stop_vifs(local);
 730
 731         if (local->ops->flush) {
 732                 ieee80211_flush_queues(local, NULL);
 733                 *next_delay = 0;
 734         } else
 735                 *next_delay = HZ / 10;
 736
 737         /* remember when we left the operating channel */
 738         local->leave_oper_channel_time = jiffies;
 739
 740         /* advance to the next channel to be scanned */
 741         local->next_scan_state = SCAN_SET_CHANNEL;
 742 }
 743
 744 void ieee80211_scan_work(struct work_struct *work)
 745 {
 746         struct ieee80211_local *local =
 747                 container_of(work, struct ieee80211_local, scan_work.work);
 748         struct ieee80211_sub_if_data *sdata;
 749         unsigned long next_delay = 0;
 750         bool aborted;
 751
 752         mutex_lock(&local->mtx);
 753
 754         sdata = rcu_dereference_protected(local->scan_sdata,
 755                                           lockdep_is_held(&local->mtx));
 756
 757         /* When scanning on-channel, the first-callback means completed. */
 758         if (test_bit(SCAN_ONCHANNEL_SCANNING, &local->scanning)) {
 759                 aborted = test_and_clear_bit(SCAN_ABORTED, &local->scanning);
 760                 goto out_complete;
 761         }
 762
 763         if (test_and_clear_bit(SCAN_COMPLETED, &local->scanning)) {
 764                 aborted = test_and_clear_bit(SCAN_ABORTED, &local->scanning);
 765                 goto out_complete;
 766         }
 767
 768         if (!sdata || !local->scan_req)
 769                 goto out;
 770
 771         if (local->scan_req && !local->scanning) {
 772                 struct cfg80211_scan_request *req = local->scan_req;
 773                 int rc;
 774
 775                 local->scan_req = NULL;
 776                 RCU_INIT_POINTER(local->scan_sdata, NULL);
 777
 778                 rc = __ieee80211_start_scan(sdata, req);
 779                 if (rc) {
 780                         /* need to complete scan in cfg80211 */
 781                         local->scan_req = req;
 782                         aborted = true;
 783                         goto out_complete;
 784                 } else
 785                         goto out;
 786         }
 787
 788         /*
 789          * as long as no delay is required advance immediately
 790          * without scheduling a new work
 791          */
 792         do {
 793                 if (!ieee80211_sdata_running(sdata)) {
 794                         aborted = true;
 795                         goto out_complete;
 796                 }
 797
 798                 switch (local->next_scan_state) {
 799                 case SCAN_DECISION:
 800                         /* if no more bands/channels left, complete scan */
 801                         if (local->scan_channel_idx >= local->scan_req->n_channels) {
 802                                 aborted = false;
 803                                 goto out_complete;
 804                         }
 805                         ieee80211_scan_state_decision(local, &next_delay);
 806                         break;
 807                 case SCAN_SET_CHANNEL:
 808                         ieee80211_scan_state_set_channel(local, &next_delay);
 809                         break;
 810                 case SCAN_SEND_PROBE:
 811                         ieee80211_scan_state_send_probe(local, &next_delay);
 812                         break;
 813                 case SCAN_SUSPEND:
 814                         ieee80211_scan_state_suspend(local, &next_delay);
 815                         break;
 816                 case SCAN_RESUME:
 817                         ieee80211_scan_state_resume(local, &next_delay);
 818                         break;
 819                 case SCAN_ABORT:
 820                         aborted = true;
 821                         goto out_complete;
 822                 }
 823         } while (next_delay == 0);
 824
 825         ieee80211_queue_delayed_work(&local->hw, &local->scan_work, next_delay);
 826         goto out;
 827
 828 out_complete:
 829         __ieee80211_scan_completed(&local->hw, aborted);
 830 out:
 831         mutex_unlock(&local->mtx);
 832 }
 833
 834 int ieee80211_request_scan(struct ieee80211_sub_if_data *sdata,
 835                            struct cfg80211_scan_request *req)
 836 {
 837         int res;
 838
 839         mutex_lock(&sdata->local->mtx);
 840         res = __ieee80211_start_scan(sdata, req);
 841         mutex_unlock(&sdata->local->mtx);
 842
 843         return res;
 844 }
 845
 846 int ieee80211_request_ibss_scan(struct ieee80211_sub_if_data *sdata,
 847                                 const u8 *ssid, u8 ssid_len,
 848                                 struct ieee80211_channel *chan,
 849                                 enum nl80211_bss_scan_width scan_width)
 850 {
 851         struct ieee80211_local *local = sdata->local;
 852         int ret = -EBUSY;
 853         enum ieee80211_band band;
 854
 855         mutex_lock(&local->mtx);
 856
 857         /* busy scanning */
 858         if (local->scan_req)
 859                 goto unlock;
 860
 861         /* fill internal scan request */
 862         if (!chan) {
 863                 int i, max_n;
 864                 int n_ch = 0;
 865
 866                 for (band = 0; band < IEEE80211_NUM_BANDS; band++) {
 867                         if (!local->hw.wiphy->bands[band])
 868                                 continue;
 869
 870                         max_n = local->hw.wiphy->bands[band]->n_channels;
 871                         for (i = 0; i < max_n; i++) {
 872                                 struct ieee80211_channel *tmp_ch =
 873                                     &local->hw.wiphy->bands[band]->channels[i];
 874
 875                                 if (tmp_ch->flags & (IEEE80211_CHAN_NO_IR |
 876                                                      IEEE80211_CHAN_DISABLED))
 877                                         continue;
 878
 879                                 local->int_scan_req->channels[n_ch] = tmp_ch;
 880                                 n_ch++;
 881                         }
 882                 }
 883
 884                 if (WARN_ON_ONCE(n_ch == 0))
 885                         goto unlock;
 886
 887                 local->int_scan_req->n_channels = n_ch;
 888         } else {
 889                 if (WARN_ON_ONCE(chan->flags & (IEEE80211_CHAN_NO_IR |
 890                                                 IEEE80211_CHAN_DISABLED)))
 891                         goto unlock;
 892
 893                 local->int_scan_req->channels[0] = chan;
 894                 local->int_scan_req->n_channels = 1;
 895         }
 896
 897         local->int_scan_req->ssids = &local->scan_ssid;
 898         local->int_scan_req->n_ssids = 1;
 899         local->int_scan_req->scan_width = scan_width;
 900         memcpy(local->int_scan_req->ssids[0].ssid, ssid, IEEE80211_MAX_SSID_LEN);
 901         local->int_scan_req->ssids[0].ssid_len = ssid_len;
 902
 903         ret = __ieee80211_start_scan(sdata, sdata->local->int_scan_req);
 904  unlock:
 905         mutex_unlock(&local->mtx);
 906         return ret;
 907 }
 908
 909 /*
 910  * Only call this function when a scan can't be queued -- under RTNL.
 911  */
 912 void ieee80211_scan_cancel(struct ieee80211_local *local)
 913 {
 914         /*
 915          * We are canceling software scan, or deferred scan that was not
 916          * yet really started (see __ieee80211_start_scan ).
 917          *
 918          * Regarding hardware scan:
 919          * - we can not call  __ieee80211_scan_completed() as when
 920          *   SCAN_HW_SCANNING bit is set this function change
 921          *   local->hw_scan_req to operate on 5G band, what race with
 922          *   driver which can use local->hw_scan_req
 923          *
 924          * - we can not cancel scan_work since driver can schedule it
 925          *   by ieee80211_scan_completed(..., true) to finish scan
 926          *
 927          * Hence we only call the cancel_hw_scan() callback, but the low-level
 928          * driver is still responsible for calling ieee80211_scan_completed()
 929          * after the scan was completed/aborted.
 930          */
 931
 932         mutex_lock(&local->mtx);
 933         if (!local->scan_req)
 934                 goto out;
 935
 936         /*
 937          * We have a scan running and the driver already reported completion,
 938          * but the worker hasn't run yet or is stuck on the mutex - mark it as
 939          * cancelled.
 940          */
 941         if (test_bit(SCAN_HW_SCANNING, &local->scanning) &&
 942             test_bit(SCAN_COMPLETED, &local->scanning)) {
 943                 set_bit(SCAN_HW_CANCELLED, &local->scanning);
 944                 goto out;
 945         }
 946
 947         if (test_bit(SCAN_HW_SCANNING, &local->scanning)) {
 948                 /*
 949                  * Make sure that __ieee80211_scan_completed doesn't trigger a
 950                  * scan on another band.
 951                  */
 952                 set_bit(SCAN_HW_CANCELLED, &local->scanning);
 953                 if (local->ops->cancel_hw_scan)
 954                         drv_cancel_hw_scan(local,
 955                                 rcu_dereference_protected(local->scan_sdata,
 956                                                 lockdep_is_held(&local->mtx)));
 957                 goto out;
 958         }
 959
 960         /*
 961          * If the work is currently running, it must be blocked on
 962          * the mutex, but we'll set scan_sdata = NULL and it'll
 963          * simply exit once it acquires the mutex.
 964          */
 965         cancel_delayed_work(&local->scan_work);
 966         /* and clean up */
 967         __ieee80211_scan_completed(&local->hw, true);
 968 out:
 969         mutex_unlock(&local->mtx);
 970 }
 971
 972 int __ieee80211_request_sched_scan_start(struct ieee80211_sub_if_data *sdata,
 973                                         struct cfg80211_sched_scan_request *req)
 974 {
 975         struct ieee80211_local *local = sdata->local;
 976         struct ieee80211_sched_scan_ies sched_scan_ies = {};
 977         struct cfg80211_chan_def chandef;
 978         int ret, i, iebufsz;
 979
 980         iebufsz = local->scan_ies_len + req->ie_len;
 981
 982         lockdep_assert_held(&local->mtx);
 983
 984         if (!local->ops->sched_scan_start)
 985                 return -ENOTSUPP;
 986
 987         for (i = 0; i < IEEE80211_NUM_BANDS; i++) {
 988                 if (!local->hw.wiphy->bands[i])
 989                         continue;
 990
 991                 sched_scan_ies.ie[i] = kzalloc(iebufsz, GFP_KERNEL);
 992                 if (!sched_scan_ies.ie[i]) {
 993                         ret = -ENOMEM;
 994                         goto out_free;
 995                 }
 996
 997                 ieee80211_prepare_scan_chandef(&chandef, req->scan_width);
 998
 999                 sched_scan_ies.len[i] =
1000                         ieee80211_build_preq_ies(local, sched_scan_ies.ie[i],
1001                                                  iebufsz, req->ie, req->ie_len,
1002                                                  i, (u32) -1, &chandef);
1003         }
1004
1005         ret = drv_sched_scan_start(local, sdata, req, &sched_scan_ies);
1006         if (ret == 0) {
1007                 rcu_assign_pointer(local->sched_scan_sdata, sdata);
1008                 local->sched_scan_req = req;
1009         }
1010
1011 out_free:
1012         while (i > 0)
1013                 kfree(sched_scan_ies.ie[--i]);
1014
1015         if (ret) {
1016                 /* Clean in case of failure after HW restart or upon resume. */
1017                 RCU_INIT_POINTER(local->sched_scan_sdata, NULL);
1018                 local->sched_scan_req = NULL;
1019         }
1020
1021         return ret;
1022 }
1023
1024 int ieee80211_request_sched_scan_start(struct ieee80211_sub_if_data *sdata,
1025                                        struct cfg80211_sched_scan_request *req)
1026 {
1027         struct ieee80211_local *local = sdata->local;
1028         int ret;
1029
1030         mutex_lock(&local->mtx);
1031
1032         if (rcu_access_pointer(local->sched_scan_sdata)) {
1033                 mutex_unlock(&local->mtx);
1034                 return -EBUSY;
1035         }
1036
1037         ret = __ieee80211_request_sched_scan_start(sdata, req);
1038
1039         mutex_unlock(&local->mtx);
1040         return ret;
1041 }
1042
1043 int ieee80211_request_sched_scan_stop(struct ieee80211_sub_if_data *sdata)
1044 {
1045         struct ieee80211_local *local = sdata->local;
1046         int ret = 0;
1047
1048         mutex_lock(&local->mtx);
1049
1050         if (!local->ops->sched_scan_stop) {
1051                 ret = -ENOTSUPP;
1052                 goto out;
1053         }
1054
1055         /* We don't want to restart sched scan anymore. */
1056         local->sched_scan_req = NULL;
1057
1058         if (rcu_access_pointer(local->sched_scan_sdata)) {
1059                 ret = drv_sched_scan_stop(local, sdata);
1060                 if (!ret)
1061                         rcu_assign_pointer(local->sched_scan_sdata, NULL);
1062         }
1063 out:
1064         mutex_unlock(&local->mtx);
1065
1066         return ret;
1067 }
1068
1069 void ieee80211_sched_scan_results(struct ieee80211_hw *hw)
1070 {
1071         struct ieee80211_local *local = hw_to_local(hw);
1072
1073         trace_api_sched_scan_results(local);
1074
1075         cfg80211_sched_scan_results(hw->wiphy);
1076 }
1077 EXPORT_SYMBOL(ieee80211_sched_scan_results);
1078
1079 void ieee80211_sched_scan_end(struct ieee80211_local *local)
1080 {
1081         mutex_lock(&local->mtx);
1082
1083         if (!rcu_access_pointer(local->sched_scan_sdata)) {
1084                 mutex_unlock(&local->mtx);
1085                 return;
1086         }
1087
1088         RCU_INIT_POINTER(local->sched_scan_sdata, NULL);
1089
1090         /* If sched scan was aborted by the driver. */
1091         local->sched_scan_req = NULL;
1092
1093         mutex_unlock(&local->mtx);
1094
1095         cfg80211_sched_scan_stopped(local->hw.wiphy);
1096 }
1097
1098 void ieee80211_sched_scan_stopped_work(struct work_struct *work)
1099 {
1100         struct ieee80211_local *local =
1101                 container_of(work, struct ieee80211_local,
1102                              sched_scan_stopped_work);
1103
1104         ieee80211_sched_scan_end(local);
1105 }
1106
1107 void ieee80211_sched_scan_stopped(struct ieee80211_hw *hw)
1108 {
1109         struct ieee80211_local *local = hw_to_local(hw);
1110
1111         trace_api_sched_scan_stopped(local);
1112
1113         schedule_work(&local->sched_scan_stopped_work);
1114 }
1115 EXPORT_SYMBOL(ieee80211_sched_scan_stopped);