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  * Copyright 2013-2015  Intel Mobile Communications GmbH
  10  *
  11  * This program is free software; you can redistribute it and/or modify
  12  * it under the terms of the GNU General Public License version 2 as
  13  * published by the Free Software Foundation.
  14  */
  15
  16 #include <linux/if_arp.h>
  17 #include <linux/etherdevice.h>
  18 #include <linux/rtnetlink.h>
  19 #include <linux/pm_qos.h>
  20 #include <net/sch_generic.h>
  21 #include <linux/slab.h>
  22 #include <linux/export.h>
  23 #include <net/mac80211.h>
  24
  25 #include "ieee80211_i.h"
  26 #include "driver-ops.h"
  27 #include "mesh.h"
  28
  29 #define IEEE80211_PROBE_DELAY (HZ / 33)
  30 #define IEEE80211_CHANNEL_TIME (HZ / 33)
  31 #define IEEE80211_PASSIVE_CHANNEL_TIME (HZ / 9)
  32
  33 void ieee80211_rx_bss_put(struct ieee80211_local *local,
  34                           struct ieee80211_bss *bss)
  35 {
  36         if (!bss)
  37                 return;
  38         cfg80211_put_bss(local->hw.wiphy,
  39                          container_of((void *)bss, struct cfg80211_bss, priv));
  40 }
  41
  42 static bool is_uapsd_supported(struct ieee802_11_elems *elems)
  43 {
  44         u8 qos_info;
  45
  46         if (elems->wmm_info && elems->wmm_info_len == 7
  47             && elems->wmm_info[5] == 1)
  48                 qos_info = elems->wmm_info[6];
  49         else if (elems->wmm_param && elems->wmm_param_len == 24
  50                  && elems->wmm_param[5] == 1)
  51                 qos_info = elems->wmm_param[6];
  52         else
  53                 /* no valid wmm information or parameter element found */
  54                 return false;
  55
  56         return qos_info & IEEE80211_WMM_IE_AP_QOSINFO_UAPSD;
  57 }
  58
  59 struct ieee80211_bss *
  60 ieee80211_bss_info_update(struct ieee80211_local *local,
  61                           struct ieee80211_rx_status *rx_status,
  62                           struct ieee80211_mgmt *mgmt, size_t len,
  63                           struct ieee802_11_elems *elems,
  64                           struct ieee80211_channel *channel)
  65 {
  66         bool beacon = ieee80211_is_beacon(mgmt->frame_control);
  67         struct cfg80211_bss *cbss;
  68         struct ieee80211_bss *bss;
  69         int clen, srlen;
  70         enum nl80211_bss_scan_width scan_width;
  71         s32 signal = 0;
  72         bool signal_valid;
  73
  74         if (ieee80211_hw_check(&local->hw, SIGNAL_DBM))
  75                 signal = rx_status->signal * 100;
  76         else if (ieee80211_hw_check(&local->hw, SIGNAL_UNSPEC))
  77                 signal = (rx_status->signal * 100) / local->hw.max_signal;
  78
  79         scan_width = NL80211_BSS_CHAN_WIDTH_20;
  80         if (rx_status->flag & RX_FLAG_5MHZ)
  81                 scan_width = NL80211_BSS_CHAN_WIDTH_5;
  82         if (rx_status->flag & RX_FLAG_10MHZ)
  83                 scan_width = NL80211_BSS_CHAN_WIDTH_10;
  84
  85         cbss = cfg80211_inform_bss_width_frame(local->hw.wiphy, channel,
  86                                                scan_width, mgmt, len, signal,
  87                                                GFP_ATOMIC);
  88         if (!cbss)
  89                 return NULL;
  90         /* In case the signal is invalid update the status */
  91         signal_valid = abs(channel->center_freq - cbss->channel->center_freq)
  92                 <= local->hw.wiphy->max_adj_channel_rssi_comp;
  93         if (!signal_valid)
  94                 rx_status->flag |= RX_FLAG_NO_SIGNAL_VAL;
  95
  96         bss = (void *)cbss->priv;
  97
  98         if (beacon)
  99                 bss->device_ts_beacon = rx_status->device_timestamp;
 100         else
 101                 bss->device_ts_presp = rx_status->device_timestamp;
 102
 103         if (elems->parse_error) {
 104                 if (beacon)
 105                         bss->corrupt_data |= IEEE80211_BSS_CORRUPT_BEACON;
 106                 else
 107                         bss->corrupt_data |= IEEE80211_BSS_CORRUPT_PROBE_RESP;
 108         } else {
 109                 if (beacon)
 110                         bss->corrupt_data &= ~IEEE80211_BSS_CORRUPT_BEACON;
 111                 else
 112                         bss->corrupt_data &= ~IEEE80211_BSS_CORRUPT_PROBE_RESP;
 113         }
 114
 115         /* save the ERP value so that it is available at association time */
 116         if (elems->erp_info && (!elems->parse_error ||
 117                                 !(bss->valid_data & IEEE80211_BSS_VALID_ERP))) {
 118                 bss->erp_value = elems->erp_info[0];
 119                 bss->has_erp_value = true;
 120                 if (!elems->parse_error)
 121                         bss->valid_data |= IEEE80211_BSS_VALID_ERP;
 122         }
 123
 124         /* replace old supported rates if we get new values */
 125         if (!elems->parse_error ||
 126             !(bss->valid_data & IEEE80211_BSS_VALID_RATES)) {
 127                 srlen = 0;
 128                 if (elems->supp_rates) {
 129                         clen = IEEE80211_MAX_SUPP_RATES;
 130                         if (clen > elems->supp_rates_len)
 131                                 clen = elems->supp_rates_len;
 132                         memcpy(bss->supp_rates, elems->supp_rates, clen);
 133                         srlen += clen;
 134                 }
 135                 if (elems->ext_supp_rates) {
 136                         clen = IEEE80211_MAX_SUPP_RATES - srlen;
 137                         if (clen > elems->ext_supp_rates_len)
 138                                 clen = elems->ext_supp_rates_len;
 139                         memcpy(bss->supp_rates + srlen, elems->ext_supp_rates,
 140                                clen);
 141                         srlen += clen;
 142                 }
 143                 if (srlen) {
 144                         bss->supp_rates_len = srlen;
 145                         if (!elems->parse_error)
 146                                 bss->valid_data |= IEEE80211_BSS_VALID_RATES;
 147                 }
 148         }
 149
 150         if (!elems->parse_error ||
 151             !(bss->valid_data & IEEE80211_BSS_VALID_WMM)) {
 152                 bss->wmm_used = elems->wmm_param || elems->wmm_info;
 153                 bss->uapsd_supported = is_uapsd_supported(elems);
 154                 if (!elems->parse_error)
 155                         bss->valid_data |= IEEE80211_BSS_VALID_WMM;
 156         }
 157
 158         if (beacon) {
 159                 struct ieee80211_supported_band *sband =
 160                         local->hw.wiphy->bands[rx_status->band];
 161                 if (!(rx_status->flag & RX_FLAG_HT) &&
 162                     !(rx_status->flag & RX_FLAG_VHT))
 163                         bss->beacon_rate =
 164                                 &sband->bitrates[rx_status->rate_idx];
 165         }
 166
 167         return bss;
 168 }
 169
 170 void ieee80211_scan_rx(struct ieee80211_local *local, struct sk_buff *skb)
 171 {
 172         struct ieee80211_rx_status *rx_status = IEEE80211_SKB_RXCB(skb);
 173         struct ieee80211_sub_if_data *sdata1, *sdata2;
 174         struct ieee80211_mgmt *mgmt = (void *)skb->data;
 175         struct ieee80211_bss *bss;
 176         u8 *elements;
 177         struct ieee80211_channel *channel;
 178         size_t baselen;
 179         struct ieee802_11_elems elems;
 180
 181         if (skb->len < 24 ||
 182             (!ieee80211_is_probe_resp(mgmt->frame_control) &&
 183              !ieee80211_is_beacon(mgmt->frame_control)))
 184                 return;
 185
 186         sdata1 = rcu_dereference(local->scan_sdata);
 187         sdata2 = rcu_dereference(local->sched_scan_sdata);
 188
 189         if (likely(!sdata1 && !sdata2))
 190                 return;
 191
 192         if (ieee80211_is_probe_resp(mgmt->frame_control)) {
 193                 struct cfg80211_scan_request *scan_req;
 194                 struct cfg80211_sched_scan_request *sched_scan_req;
 195
 196                 scan_req = rcu_dereference(local->scan_req);
 197                 sched_scan_req = rcu_dereference(local->sched_scan_req);
 198
 199                 /* ignore ProbeResp to foreign address unless scanning
 200                  * with randomised address
 201                  */
 202                 if (!(sdata1 &&
 203                       (ether_addr_equal(mgmt->da, sdata1->vif.addr) ||
 204                        scan_req->flags & NL80211_SCAN_FLAG_RANDOM_ADDR)) &&
 205                     !(sdata2 &&
 206                       (ether_addr_equal(mgmt->da, sdata2->vif.addr) ||
 207                        sched_scan_req->flags & NL80211_SCAN_FLAG_RANDOM_ADDR)))
 208                         return;
 209
 210                 elements = mgmt->u.probe_resp.variable;
 211                 baselen = offsetof(struct ieee80211_mgmt, u.probe_resp.variable);
 212         } else {
 213                 baselen = offsetof(struct ieee80211_mgmt, u.beacon.variable);
 214                 elements = mgmt->u.beacon.variable;
 215         }
 216
 217         if (baselen > skb->len)
 218                 return;
 219
 220         ieee802_11_parse_elems(elements, skb->len - baselen, false, &elems);
 221
 222         channel = ieee80211_get_channel(local->hw.wiphy, rx_status->freq);
 223
 224         if (!channel || channel->flags & IEEE80211_CHAN_DISABLED)
 225                 return;
 226
 227         bss = ieee80211_bss_info_update(local, rx_status,
 228                                         mgmt, skb->len, &elems,
 229                                         channel);
 230         if (bss)
 231                 ieee80211_rx_bss_put(local, bss);
 232 }
 233
 234 static void
 235 ieee80211_prepare_scan_chandef(struct cfg80211_chan_def *chandef,
 236                                enum nl80211_bss_scan_width scan_width)
 237 {
 238         memset(chandef, 0, sizeof(*chandef));
 239         switch (scan_width) {
 240         case NL80211_BSS_CHAN_WIDTH_5:
 241                 chandef->width = NL80211_CHAN_WIDTH_5;
 242                 break;
 243         case NL80211_BSS_CHAN_WIDTH_10:
 244                 chandef->width = NL80211_CHAN_WIDTH_10;
 245                 break;
 246         default:
 247                 chandef->width = NL80211_CHAN_WIDTH_20_NOHT;
 248                 break;
 249         }
 250 }
 251
 252 /* return false if no more work */
 253 static bool ieee80211_prep_hw_scan(struct ieee80211_local *local)
 254 {
 255         struct cfg80211_scan_request *req;
 256         struct cfg80211_chan_def chandef;
 257         u8 bands_used = 0;
 258         int i, ielen, n_chans;
 259
 260         req = rcu_dereference_protected(local->scan_req,
 261                                         lockdep_is_held(&local->mtx));
 262
 263         if (test_bit(SCAN_HW_CANCELLED, &local->scanning))
 264                 return false;
 265
 266         if (ieee80211_hw_check(&local->hw, SINGLE_SCAN_ON_ALL_BANDS)) {
 267                 for (i = 0; i < req->n_channels; i++) {
 268                         local->hw_scan_req->req.channels[i] = req->channels[i];
 269                         bands_used |= BIT(req->channels[i]->band);
 270                 }
 271
 272                 n_chans = req->n_channels;
 273         } else {
 274                 do {
 275                         if (local->hw_scan_band == IEEE80211_NUM_BANDS)
 276                                 return false;
 277
 278                         n_chans = 0;
 279
 280                         for (i = 0; i < req->n_channels; i++) {
 281                                 if (req->channels[i]->band !=
 282                                     local->hw_scan_band)
 283                                         continue;
 284                                 local->hw_scan_req->req.channels[n_chans] =
 285                                                         req->channels[i];
 286                                 n_chans++;
 287                                 bands_used |= BIT(req->channels[i]->band);
 288                         }
 289
 290                         local->hw_scan_band++;
 291                 } while (!n_chans);
 292         }
 293
 294         local->hw_scan_req->req.n_channels = n_chans;
 295         ieee80211_prepare_scan_chandef(&chandef, req->scan_width);
 296
 297         ielen = ieee80211_build_preq_ies(local,
 298                                          (u8 *)local->hw_scan_req->req.ie,
 299                                          local->hw_scan_ies_bufsize,
 300                                          &local->hw_scan_req->ies,
 301                                          req->ie, req->ie_len,
 302                                          bands_used, req->rates, &chandef);
 303         local->hw_scan_req->req.ie_len = ielen;
 304         local->hw_scan_req->req.no_cck = req->no_cck;
 305         ether_addr_copy(local->hw_scan_req->req.mac_addr, req->mac_addr);
 306         ether_addr_copy(local->hw_scan_req->req.mac_addr_mask,
 307                         req->mac_addr_mask);
 308
 309         return true;
 310 }
 311
 312 static void __ieee80211_scan_completed(struct ieee80211_hw *hw, bool aborted)
 313 {
 314         struct ieee80211_local *local = hw_to_local(hw);
 315         bool hw_scan = local->ops->hw_scan;
 316         bool was_scanning = local->scanning;
 317         struct cfg80211_scan_request *scan_req;
 318         struct ieee80211_sub_if_data *scan_sdata;
 319
 320         lockdep_assert_held(&local->mtx);
 321
 322         /*
 323          * It's ok to abort a not-yet-running scan (that
 324          * we have one at all will be verified by checking
 325          * local->scan_req next), but not to complete it
 326          * successfully.
 327          */
 328         if (WARN_ON(!local->scanning && !aborted))
 329                 aborted = true;
 330
 331         if (WARN_ON(!local->scan_req))
 332                 return;
 333
 334         if (hw_scan && !aborted &&
 335             !ieee80211_hw_check(&local->hw, SINGLE_SCAN_ON_ALL_BANDS) &&
 336             ieee80211_prep_hw_scan(local)) {
 337                 int rc;
 338
 339                 rc = drv_hw_scan(local,
 340                         rcu_dereference_protected(local->scan_sdata,
 341                                                   lockdep_is_held(&local->mtx)),
 342                         local->hw_scan_req);
 343
 344                 if (rc == 0)
 345                         return;
 346         }
 347
 348         kfree(local->hw_scan_req);
 349         local->hw_scan_req = NULL;
 350
 351         scan_req = rcu_dereference_protected(local->scan_req,
 352                                              lockdep_is_held(&local->mtx));
 353
 354         if (scan_req != local->int_scan_req)
 355                 cfg80211_scan_done(scan_req, aborted);
 356         RCU_INIT_POINTER(local->scan_req, NULL);
 357
 358         scan_sdata = rcu_dereference_protected(local->scan_sdata,
 359                                                lockdep_is_held(&local->mtx));
 360         RCU_INIT_POINTER(local->scan_sdata, NULL);
 361
 362         local->scanning = 0;
 363         local->scan_chandef.chan = NULL;
 364
 365         /* Set power back to normal operating levels. */
 366         ieee80211_hw_config(local, 0);
 367
 368         if (!hw_scan) {
 369                 ieee80211_configure_filter(local);
 370                 drv_sw_scan_complete(local, scan_sdata);
 371                 ieee80211_offchannel_return(local);
 372         }
 373
 374         ieee80211_recalc_idle(local);
 375
 376         ieee80211_mlme_notify_scan_completed(local);
 377         ieee80211_ibss_notify_scan_completed(local);
 378         ieee80211_mesh_notify_scan_completed(local);
 379         if (was_scanning)
 380                 ieee80211_start_next_roc(local);
 381 }
 382
 383 void ieee80211_scan_completed(struct ieee80211_hw *hw, bool aborted)
 384 {
 385         struct ieee80211_local *local = hw_to_local(hw);
 386
 387         trace_api_scan_completed(local, aborted);
 388
 389         set_bit(SCAN_COMPLETED, &local->scanning);
 390         if (aborted)
 391                 set_bit(SCAN_ABORTED, &local->scanning);
 392         ieee80211_queue_delayed_work(&local->hw, &local->scan_work, 0);
 393 }
 394 EXPORT_SYMBOL(ieee80211_scan_completed);
 395
 396 static int ieee80211_start_sw_scan(struct ieee80211_local *local,
 397                                    struct ieee80211_sub_if_data *sdata)
 398 {
 399         /* Software scan is not supported in multi-channel cases */
 400         if (local->use_chanctx)
 401                 return -EOPNOTSUPP;
 402
 403         /*
 404          * Hardware/driver doesn't support hw_scan, so use software
 405          * scanning instead. First send a nullfunc frame with power save
 406          * bit on so that AP will buffer the frames for us while we are not
 407          * listening, then send probe requests to each channel and wait for
 408          * the responses. After all channels are scanned, tune back to the
 409          * original channel and send a nullfunc frame with power save bit
 410          * off to trigger the AP to send us all the buffered frames.
 411          *
 412          * Note that while local->sw_scanning is true everything else but
 413          * nullfunc frames and probe requests will be dropped in
 414          * ieee80211_tx_h_check_assoc().
 415          */
 416         drv_sw_scan_start(local, sdata, local->scan_addr);
 417
 418         local->leave_oper_channel_time = jiffies;
 419         local->next_scan_state = SCAN_DECISION;
 420         local->scan_channel_idx = 0;
 421
 422         ieee80211_offchannel_stop_vifs(local);
 423
 424         /* ensure nullfunc is transmitted before leaving operating channel */
 425         ieee80211_flush_queues(local, NULL, false);
 426
 427         ieee80211_configure_filter(local);
 428
 429         /* We need to set power level at maximum rate for scanning. */
 430         ieee80211_hw_config(local, 0);
 431
 432         ieee80211_queue_delayed_work(&local->hw,
 433                                      &local->scan_work, 0);
 434
 435         return 0;
 436 }
 437
 438 static bool ieee80211_can_scan(struct ieee80211_local *local,
 439                                struct ieee80211_sub_if_data *sdata)
 440 {
 441         if (ieee80211_is_radar_required(local))
 442                 return false;
 443
 444         if (!list_empty(&local->roc_list))
 445                 return false;
 446
 447         if (sdata->vif.type == NL80211_IFTYPE_STATION &&
 448             sdata->u.mgd.flags & IEEE80211_STA_CONNECTION_POLL)
 449                 return false;
 450
 451         return true;
 452 }
 453
 454 void ieee80211_run_deferred_scan(struct ieee80211_local *local)
 455 {
 456         lockdep_assert_held(&local->mtx);
 457
 458         if (!local->scan_req || local->scanning)
 459                 return;
 460
 461         if (!ieee80211_can_scan(local,
 462                                 rcu_dereference_protected(
 463                                         local->scan_sdata,
 464                                         lockdep_is_held(&local->mtx))))
 465                 return;
 466
 467         ieee80211_queue_delayed_work(&local->hw, &local->scan_work,
 468                                      round_jiffies_relative(0));
 469 }
 470
 471 static void ieee80211_scan_state_send_probe(struct ieee80211_local *local,
 472                                             unsigned long *next_delay)
 473 {
 474         int i;
 475         struct ieee80211_sub_if_data *sdata;
 476         struct cfg80211_scan_request *scan_req;
 477         enum ieee80211_band band = local->hw.conf.chandef.chan->band;
 478         u32 tx_flags;
 479
 480         scan_req = rcu_dereference_protected(local->scan_req,
 481                                              lockdep_is_held(&local->mtx));
 482
 483         tx_flags = IEEE80211_TX_INTFL_OFFCHAN_TX_OK;
 484         if (scan_req->no_cck)
 485                 tx_flags |= IEEE80211_TX_CTL_NO_CCK_RATE;
 486
 487         sdata = rcu_dereference_protected(local->scan_sdata,
 488                                           lockdep_is_held(&local->mtx));
 489
 490         for (i = 0; i < scan_req->n_ssids; i++)
 491                 ieee80211_send_probe_req(
 492                         sdata, local->scan_addr, NULL,
 493                         scan_req->ssids[i].ssid, scan_req->ssids[i].ssid_len,
 494                         scan_req->ie, scan_req->ie_len,
 495                         scan_req->rates[band], false,
 496                         tx_flags, local->hw.conf.chandef.chan, true);
 497
 498         /*
 499          * After sending probe requests, wait for probe responses
 500          * on the channel.
 501          */
 502         *next_delay = IEEE80211_CHANNEL_TIME;
 503         local->next_scan_state = SCAN_DECISION;
 504 }
 505
 506 static int __ieee80211_start_scan(struct ieee80211_sub_if_data *sdata,
 507                                   struct cfg80211_scan_request *req)
 508 {
 509         struct ieee80211_local *local = sdata->local;
 510         int rc;
 511
 512         lockdep_assert_held(&local->mtx);
 513
 514         if (local->scan_req || ieee80211_is_radar_required(local))
 515                 return -EBUSY;
 516
 517         if (!ieee80211_can_scan(local, sdata)) {
 518                 /* wait for the work to finish/time out */
 519                 rcu_assign_pointer(local->scan_req, req);
 520                 rcu_assign_pointer(local->scan_sdata, sdata);
 521                 return 0;
 522         }
 523
 524         if (local->ops->hw_scan) {
 525                 u8 *ies;
 526
 527                 local->hw_scan_ies_bufsize = local->scan_ies_len + req->ie_len;
 528
 529                 if (ieee80211_hw_check(&local->hw, SINGLE_SCAN_ON_ALL_BANDS)) {
 530                         int i, n_bands = 0;
 531                         u8 bands_counted = 0;
 532
 533                         for (i = 0; i < req->n_channels; i++) {
 534                                 if (bands_counted & BIT(req->channels[i]->band))
 535                                         continue;
 536                                 bands_counted |= BIT(req->channels[i]->band);
 537                                 n_bands++;
 538                         }
 539
 540                         local->hw_scan_ies_bufsize *= n_bands;
 541                 }
 542
 543                 local->hw_scan_req = kmalloc(
 544                                 sizeof(*local->hw_scan_req) +
 545                                 req->n_channels * sizeof(req->channels[0]) +
 546                                 local->hw_scan_ies_bufsize, GFP_KERNEL);
 547                 if (!local->hw_scan_req)
 548                         return -ENOMEM;
 549
 550                 local->hw_scan_req->req.ssids = req->ssids;
 551                 local->hw_scan_req->req.n_ssids = req->n_ssids;
 552                 ies = (u8 *)local->hw_scan_req +
 553                         sizeof(*local->hw_scan_req) +
 554                         req->n_channels * sizeof(req->channels[0]);
 555                 local->hw_scan_req->req.ie = ies;
 556                 local->hw_scan_req->req.flags = req->flags;
 557
 558                 local->hw_scan_band = 0;
 559
 560                 /*
 561                  * After allocating local->hw_scan_req, we must
 562                  * go through until ieee80211_prep_hw_scan(), so
 563                  * anything that might be changed here and leave
 564                  * this function early must not go after this
 565                  * allocation.
 566                  */
 567         }
 568
 569         rcu_assign_pointer(local->scan_req, req);
 570         rcu_assign_pointer(local->scan_sdata, sdata);
 571
 572         if (req->flags & NL80211_SCAN_FLAG_RANDOM_ADDR)
 573                 get_random_mask_addr(local->scan_addr,
 574                                      req->mac_addr,
 575                                      req->mac_addr_mask);
 576         else
 577                 memcpy(local->scan_addr, sdata->vif.addr, ETH_ALEN);
 578
 579         if (local->ops->hw_scan) {
 580                 __set_bit(SCAN_HW_SCANNING, &local->scanning);
 581         } else if ((req->n_channels == 1) &&
 582                    (req->channels[0] == local->_oper_chandef.chan)) {
 583                 /*
 584                  * If we are scanning only on the operating channel
 585                  * then we do not need to stop normal activities
 586                  */
 587                 unsigned long next_delay;
 588
 589                 __set_bit(SCAN_ONCHANNEL_SCANNING, &local->scanning);
 590
 591                 ieee80211_recalc_idle(local);
 592
 593                 /* Notify driver scan is starting, keep order of operations
 594                  * same as normal software scan, in case that matters. */
 595                 drv_sw_scan_start(local, sdata, local->scan_addr);
 596
 597                 ieee80211_configure_filter(local); /* accept probe-responses */
 598
 599                 /* We need to ensure power level is at max for scanning. */
 600                 ieee80211_hw_config(local, 0);
 601
 602                 if ((req->channels[0]->flags &
 603                      IEEE80211_CHAN_NO_IR) ||
 604                     !req->n_ssids) {
 605                         next_delay = IEEE80211_PASSIVE_CHANNEL_TIME;
 606                 } else {
 607                         ieee80211_scan_state_send_probe(local, &next_delay);
 608                         next_delay = IEEE80211_CHANNEL_TIME;
 609                 }
 610
 611                 /* Now, just wait a bit and we are all done! */
 612                 ieee80211_queue_delayed_work(&local->hw, &local->scan_work,
 613                                              next_delay);
 614                 return 0;
 615         } else {
 616                 /* Do normal software scan */
 617                 __set_bit(SCAN_SW_SCANNING, &local->scanning);
 618         }
 619
 620         ieee80211_recalc_idle(local);
 621
 622         if (local->ops->hw_scan) {
 623                 WARN_ON(!ieee80211_prep_hw_scan(local));
 624                 rc = drv_hw_scan(local, sdata, local->hw_scan_req);
 625         } else {
 626                 rc = ieee80211_start_sw_scan(local, sdata);
 627         }
 628
 629         if (rc) {
 630                 kfree(local->hw_scan_req);
 631                 local->hw_scan_req = NULL;
 632                 local->scanning = 0;
 633
 634                 ieee80211_recalc_idle(local);
 635
 636                 local->scan_req = NULL;
 637                 RCU_INIT_POINTER(local->scan_sdata, NULL);
 638         }
 639
 640         return rc;
 641 }
 642
 643 static unsigned long
 644 ieee80211_scan_get_channel_time(struct ieee80211_channel *chan)
 645 {
 646         /*
 647          * TODO: channel switching also consumes quite some time,
 648          * add that delay as well to get a better estimation
 649          */
 650         if (chan->flags & IEEE80211_CHAN_NO_IR)
 651                 return IEEE80211_PASSIVE_CHANNEL_TIME;
 652         return IEEE80211_PROBE_DELAY + IEEE80211_CHANNEL_TIME;
 653 }
 654
 655 static void ieee80211_scan_state_decision(struct ieee80211_local *local,
 656                                           unsigned long *next_delay)
 657 {
 658         bool associated = false;
 659         bool tx_empty = true;
 660         bool bad_latency;
 661         struct ieee80211_sub_if_data *sdata;
 662         struct ieee80211_channel *next_chan;
 663         enum mac80211_scan_state next_scan_state;
 664         struct cfg80211_scan_request *scan_req;
 665
 666         /*
 667          * check if at least one STA interface is associated,
 668          * check if at least one STA interface has pending tx frames
 669          * and grab the lowest used beacon interval
 670          */
 671         mutex_lock(&local->iflist_mtx);
 672         list_for_each_entry(sdata, &local->interfaces, list) {
 673                 if (!ieee80211_sdata_running(sdata))
 674                         continue;
 675
 676                 if (sdata->vif.type == NL80211_IFTYPE_STATION) {
 677                         if (sdata->u.mgd.associated) {
 678                                 associated = true;
 679
 680                                 if (!qdisc_all_tx_empty(sdata->dev)) {
 681                                         tx_empty = false;
 682                                         break;
 683                                 }
 684                         }
 685                 }
 686         }
 687         mutex_unlock(&local->iflist_mtx);
 688
 689         scan_req = rcu_dereference_protected(local->scan_req,
 690                                              lockdep_is_held(&local->mtx));
 691
 692         next_chan = scan_req->channels[local->scan_channel_idx];
 693
 694         /*
 695          * we're currently scanning a different channel, let's
 696          * see if we can scan another channel without interfering
 697          * with the current traffic situation.
 698          *
 699          * Keep good latency, do not stay off-channel more than 125 ms.
 700          */
 701
 702         bad_latency = time_after(jiffies +
 703                                  ieee80211_scan_get_channel_time(next_chan),
 704                                  local->leave_oper_channel_time + HZ / 8);
 705
 706         if (associated && !tx_empty) {
 707                 if (scan_req->flags & NL80211_SCAN_FLAG_LOW_PRIORITY)
 708                         next_scan_state = SCAN_ABORT;
 709                 else
 710                         next_scan_state = SCAN_SUSPEND;
 711         } else if (associated && bad_latency) {
 712                 next_scan_state = SCAN_SUSPEND;
 713         } else {
 714                 next_scan_state = SCAN_SET_CHANNEL;
 715         }
 716
 717         local->next_scan_state = next_scan_state;
 718
 719         *next_delay = 0;
 720 }
 721
 722 static void ieee80211_scan_state_set_channel(struct ieee80211_local *local,
 723                                              unsigned long *next_delay)
 724 {
 725         int skip;
 726         struct ieee80211_channel *chan;
 727         enum nl80211_bss_scan_width oper_scan_width;
 728         struct cfg80211_scan_request *scan_req;
 729
 730         scan_req = rcu_dereference_protected(local->scan_req,
 731                                              lockdep_is_held(&local->mtx));
 732
 733         skip = 0;
 734         chan = scan_req->channels[local->scan_channel_idx];
 735
 736         local->scan_chandef.chan = chan;
 737         local->scan_chandef.center_freq1 = chan->center_freq;
 738         local->scan_chandef.center_freq2 = 0;
 739         switch (scan_req->scan_width) {
 740         case NL80211_BSS_CHAN_WIDTH_5:
 741                 local->scan_chandef.width = NL80211_CHAN_WIDTH_5;
 742                 break;
 743         case NL80211_BSS_CHAN_WIDTH_10:
 744                 local->scan_chandef.width = NL80211_CHAN_WIDTH_10;
 745                 break;
 746         case NL80211_BSS_CHAN_WIDTH_20:
 747                 /* If scanning on oper channel, use whatever channel-type
 748                  * is currently in use.
 749                  */
 750                 oper_scan_width = cfg80211_chandef_to_scan_width(
 751                                         &local->_oper_chandef);
 752                 if (chan == local->_oper_chandef.chan &&
 753                     oper_scan_width == scan_req->scan_width)
 754                         local->scan_chandef = local->_oper_chandef;
 755                 else
 756                         local->scan_chandef.width = NL80211_CHAN_WIDTH_20_NOHT;
 757                 break;
 758         }
 759
 760         if (ieee80211_hw_config(local, IEEE80211_CONF_CHANGE_CHANNEL))
 761                 skip = 1;
 762
 763         /* advance state machine to next channel/band */
 764         local->scan_channel_idx++;
 765
 766         if (skip) {
 767                 /* if we skip this channel return to the decision state */
 768                 local->next_scan_state = SCAN_DECISION;
 769                 return;
 770         }
 771
 772         /*
 773          * Probe delay is used to update the NAV, cf. 11.1.3.2.2
 774          * (which unfortunately doesn't say _why_ step a) is done,
 775          * but it waits for the probe delay or until a frame is
 776          * received - and the received frame would update the NAV).
 777          * For now, we do not support waiting until a frame is
 778          * received.
 779          *
 780          * In any case, it is not necessary for a passive scan.
 781          */
 782         if (chan->flags & IEEE80211_CHAN_NO_IR || !scan_req->n_ssids) {
 783                 *next_delay = IEEE80211_PASSIVE_CHANNEL_TIME;
 784                 local->next_scan_state = SCAN_DECISION;
 785                 return;
 786         }
 787
 788         /* active scan, send probes */
 789         *next_delay = IEEE80211_PROBE_DELAY;
 790         local->next_scan_state = SCAN_SEND_PROBE;
 791 }
 792
 793 static void ieee80211_scan_state_suspend(struct ieee80211_local *local,
 794                                          unsigned long *next_delay)
 795 {
 796         /* switch back to the operating channel */
 797         local->scan_chandef.chan = NULL;
 798         ieee80211_hw_config(local, IEEE80211_CONF_CHANGE_CHANNEL);
 799
 800         /* disable PS */
 801         ieee80211_offchannel_return(local);
 802
 803         *next_delay = HZ / 5;
 804         /* afterwards, resume scan & go to next channel */
 805         local->next_scan_state = SCAN_RESUME;
 806 }
 807
 808 static void ieee80211_scan_state_resume(struct ieee80211_local *local,
 809                                         unsigned long *next_delay)
 810 {
 811         ieee80211_offchannel_stop_vifs(local);
 812
 813         if (local->ops->flush) {
 814                 ieee80211_flush_queues(local, NULL, false);
 815                 *next_delay = 0;
 816         } else
 817                 *next_delay = HZ / 10;
 818
 819         /* remember when we left the operating channel */
 820         local->leave_oper_channel_time = jiffies;
 821
 822         /* advance to the next channel to be scanned */
 823         local->next_scan_state = SCAN_SET_CHANNEL;
 824 }
 825
 826 void ieee80211_scan_work(struct work_struct *work)
 827 {
 828         struct ieee80211_local *local =
 829                 container_of(work, struct ieee80211_local, scan_work.work);
 830         struct ieee80211_sub_if_data *sdata;
 831         struct cfg80211_scan_request *scan_req;
 832         unsigned long next_delay = 0;
 833         bool aborted;
 834
 835         mutex_lock(&local->mtx);
 836
 837         if (!ieee80211_can_run_worker(local)) {
 838                 aborted = true;
 839                 goto out_complete;
 840         }
 841
 842         sdata = rcu_dereference_protected(local->scan_sdata,
 843                                           lockdep_is_held(&local->mtx));
 844         scan_req = rcu_dereference_protected(local->scan_req,
 845                                              lockdep_is_held(&local->mtx));
 846
 847         /* When scanning on-channel, the first-callback means completed. */
 848         if (test_bit(SCAN_ONCHANNEL_SCANNING, &local->scanning)) {
 849                 aborted = test_and_clear_bit(SCAN_ABORTED, &local->scanning);
 850                 goto out_complete;
 851         }
 852
 853         if (test_and_clear_bit(SCAN_COMPLETED, &local->scanning)) {
 854                 aborted = test_and_clear_bit(SCAN_ABORTED, &local->scanning);
 855                 goto out_complete;
 856         }
 857
 858         if (!sdata || !scan_req)
 859                 goto out;
 860
 861         if (!local->scanning) {
 862                 int rc;
 863
 864                 RCU_INIT_POINTER(local->scan_req, NULL);
 865                 RCU_INIT_POINTER(local->scan_sdata, NULL);
 866
 867                 rc = __ieee80211_start_scan(sdata, scan_req);
 868                 if (rc) {
 869                         /* need to complete scan in cfg80211 */
 870                         rcu_assign_pointer(local->scan_req, scan_req);
 871                         aborted = true;
 872                         goto out_complete;
 873                 } else
 874                         goto out;
 875         }
 876
 877         /*
 878          * as long as no delay is required advance immediately
 879          * without scheduling a new work
 880          */
 881         do {
 882                 if (!ieee80211_sdata_running(sdata)) {
 883                         aborted = true;
 884                         goto out_complete;
 885                 }
 886
 887                 switch (local->next_scan_state) {
 888                 case SCAN_DECISION:
 889                         /* if no more bands/channels left, complete scan */
 890                         if (local->scan_channel_idx >= scan_req->n_channels) {
 891                                 aborted = false;
 892                                 goto out_complete;
 893                         }
 894                         ieee80211_scan_state_decision(local, &next_delay);
 895                         break;
 896                 case SCAN_SET_CHANNEL:
 897                         ieee80211_scan_state_set_channel(local, &next_delay);
 898                         break;
 899                 case SCAN_SEND_PROBE:
 900                         ieee80211_scan_state_send_probe(local, &next_delay);
 901                         break;
 902                 case SCAN_SUSPEND:
 903                         ieee80211_scan_state_suspend(local, &next_delay);
 904                         break;
 905                 case SCAN_RESUME:
 906                         ieee80211_scan_state_resume(local, &next_delay);
 907                         break;
 908                 case SCAN_ABORT:
 909                         aborted = true;
 910                         goto out_complete;
 911                 }
 912         } while (next_delay == 0);
 913
 914         ieee80211_queue_delayed_work(&local->hw, &local->scan_work, next_delay);
 915         goto out;
 916
 917 out_complete:
 918         __ieee80211_scan_completed(&local->hw, aborted);
 919 out:
 920         mutex_unlock(&local->mtx);
 921 }
 922
 923 int ieee80211_request_scan(struct ieee80211_sub_if_data *sdata,
 924                            struct cfg80211_scan_request *req)
 925 {
 926         int res;
 927
 928         mutex_lock(&sdata->local->mtx);
 929         res = __ieee80211_start_scan(sdata, req);
 930         mutex_unlock(&sdata->local->mtx);
 931
 932         return res;
 933 }
 934
 935 int ieee80211_request_ibss_scan(struct ieee80211_sub_if_data *sdata,
 936                                 const u8 *ssid, u8 ssid_len,
 937                                 struct ieee80211_channel **channels,
 938                                 unsigned int n_channels,
 939                                 enum nl80211_bss_scan_width scan_width)
 940 {
 941         struct ieee80211_local *local = sdata->local;
 942         int ret = -EBUSY, i, n_ch = 0;
 943         enum ieee80211_band band;
 944
 945         mutex_lock(&local->mtx);
 946
 947         /* busy scanning */
 948         if (local->scan_req)
 949                 goto unlock;
 950
 951         /* fill internal scan request */
 952         if (!channels) {
 953                 int max_n;
 954
 955                 for (band = 0; band < IEEE80211_NUM_BANDS; band++) {
 956                         if (!local->hw.wiphy->bands[band])
 957                                 continue;
 958
 959                         max_n = local->hw.wiphy->bands[band]->n_channels;
 960                         for (i = 0; i < max_n; i++) {
 961                                 struct ieee80211_channel *tmp_ch =
 962                                     &local->hw.wiphy->bands[band]->channels[i];
 963
 964                                 if (tmp_ch->flags & (IEEE80211_CHAN_NO_IR |
 965                                                      IEEE80211_CHAN_DISABLED))
 966                                         continue;
 967
 968                                 local->int_scan_req->channels[n_ch] = tmp_ch;
 969                                 n_ch++;
 970                         }
 971                 }
 972
 973                 if (WARN_ON_ONCE(n_ch == 0))
 974                         goto unlock;
 975
 976                 local->int_scan_req->n_channels = n_ch;
 977         } else {
 978                 for (i = 0; i < n_channels; i++) {
 979                         if (channels[i]->flags & (IEEE80211_CHAN_NO_IR |
 980                                                   IEEE80211_CHAN_DISABLED))
 981                                 continue;
 982
 983                         local->int_scan_req->channels[n_ch] = channels[i];
 984                         n_ch++;
 985                 }
 986
 987                 if (WARN_ON_ONCE(n_ch == 0))
 988                         goto unlock;
 989
 990                 local->int_scan_req->n_channels = n_ch;
 991         }
 992
 993         local->int_scan_req->ssids = &local->scan_ssid;
 994         local->int_scan_req->n_ssids = 1;
 995         local->int_scan_req->scan_width = scan_width;
 996         memcpy(local->int_scan_req->ssids[0].ssid, ssid, IEEE80211_MAX_SSID_LEN);
 997         local->int_scan_req->ssids[0].ssid_len = ssid_len;
 998
 999         ret = __ieee80211_start_scan(sdata, sdata->local->int_scan_req);
1000  unlock:
1001         mutex_unlock(&local->mtx);
1002         return ret;
1003 }
1004
1005 /*
1006  * Only call this function when a scan can't be queued -- under RTNL.
1007  */
1008 void ieee80211_scan_cancel(struct ieee80211_local *local)
1009 {
1010         /*
1011          * We are canceling software scan, or deferred scan that was not
1012          * yet really started (see __ieee80211_start_scan ).
1013          *
1014          * Regarding hardware scan:
1015          * - we can not call  __ieee80211_scan_completed() as when
1016          *   SCAN_HW_SCANNING bit is set this function change
1017          *   local->hw_scan_req to operate on 5G band, what race with
1018          *   driver which can use local->hw_scan_req
1019          *
1020          * - we can not cancel scan_work since driver can schedule it
1021          *   by ieee80211_scan_completed(..., true) to finish scan
1022          *
1023          * Hence we only call the cancel_hw_scan() callback, but the low-level
1024          * driver is still responsible for calling ieee80211_scan_completed()
1025          * after the scan was completed/aborted.
1026          */
1027
1028         mutex_lock(&local->mtx);
1029         if (!local->scan_req)
1030                 goto out;
1031
1032         /*
1033          * We have a scan running and the driver already reported completion,
1034          * but the worker hasn't run yet or is stuck on the mutex - mark it as
1035          * cancelled.
1036          */
1037         if (test_bit(SCAN_HW_SCANNING, &local->scanning) &&
1038             test_bit(SCAN_COMPLETED, &local->scanning)) {
1039                 set_bit(SCAN_HW_CANCELLED, &local->scanning);
1040                 goto out;
1041         }
1042
1043         if (test_bit(SCAN_HW_SCANNING, &local->scanning)) {
1044                 /*
1045                  * Make sure that __ieee80211_scan_completed doesn't trigger a
1046                  * scan on another band.
1047                  */
1048                 set_bit(SCAN_HW_CANCELLED, &local->scanning);
1049                 if (local->ops->cancel_hw_scan)
1050                         drv_cancel_hw_scan(local,
1051                                 rcu_dereference_protected(local->scan_sdata,
1052                                                 lockdep_is_held(&local->mtx)));
1053                 goto out;
1054         }
1055
1056         /*
1057          * If the work is currently running, it must be blocked on
1058          * the mutex, but we'll set scan_sdata = NULL and it'll
1059          * simply exit once it acquires the mutex.
1060          */
1061         cancel_delayed_work(&local->scan_work);
1062         /* and clean up */
1063         __ieee80211_scan_completed(&local->hw, true);
1064 out:
1065         mutex_unlock(&local->mtx);
1066 }
1067
1068 int __ieee80211_request_sched_scan_start(struct ieee80211_sub_if_data *sdata,
1069                                         struct cfg80211_sched_scan_request *req)
1070 {
1071         struct ieee80211_local *local = sdata->local;
1072         struct ieee80211_scan_ies sched_scan_ies = {};
1073         struct cfg80211_chan_def chandef;
1074         int ret, i, iebufsz, num_bands = 0;
1075         u32 rate_masks[IEEE80211_NUM_BANDS] = {};
1076         u8 bands_used = 0;
1077         u8 *ie;
1078         size_t len;
1079
1080         iebufsz = local->scan_ies_len + req->ie_len;
1081
1082         lockdep_assert_held(&local->mtx);
1083
1084         if (!local->ops->sched_scan_start)
1085                 return -ENOTSUPP;
1086
1087         for (i = 0; i < IEEE80211_NUM_BANDS; i++) {
1088                 if (local->hw.wiphy->bands[i]) {
1089                         bands_used |= BIT(i);
1090                         rate_masks[i] = (u32) -1;
1091                         num_bands++;
1092                 }
1093         }
1094
1095         ie = kzalloc(num_bands * iebufsz, GFP_KERNEL);
1096         if (!ie) {
1097                 ret = -ENOMEM;
1098                 goto out;
1099         }
1100
1101         ieee80211_prepare_scan_chandef(&chandef, req->scan_width);
1102
1103         len = ieee80211_build_preq_ies(local, ie, num_bands * iebufsz,
1104                                        &sched_scan_ies, req->ie,
1105                                        req->ie_len, bands_used,
1106                                        rate_masks, &chandef);
1107
1108         ret = drv_sched_scan_start(local, sdata, req, &sched_scan_ies);
1109         if (ret == 0) {
1110                 rcu_assign_pointer(local->sched_scan_sdata, sdata);
1111                 rcu_assign_pointer(local->sched_scan_req, req);
1112         }
1113
1114         kfree(ie);
1115
1116 out:
1117         if (ret) {
1118                 /* Clean in case of failure after HW restart or upon resume. */
1119                 RCU_INIT_POINTER(local->sched_scan_sdata, NULL);
1120                 RCU_INIT_POINTER(local->sched_scan_req, NULL);
1121         }
1122
1123         return ret;
1124 }
1125
1126 int ieee80211_request_sched_scan_start(struct ieee80211_sub_if_data *sdata,
1127                                        struct cfg80211_sched_scan_request *req)
1128 {
1129         struct ieee80211_local *local = sdata->local;
1130         int ret;
1131
1132         mutex_lock(&local->mtx);
1133
1134         if (rcu_access_pointer(local->sched_scan_sdata)) {
1135                 mutex_unlock(&local->mtx);
1136                 return -EBUSY;
1137         }
1138
1139         ret = __ieee80211_request_sched_scan_start(sdata, req);
1140
1141         mutex_unlock(&local->mtx);
1142         return ret;
1143 }
1144
1145 int ieee80211_request_sched_scan_stop(struct ieee80211_sub_if_data *sdata)
1146 {
1147         struct ieee80211_local *local = sdata->local;
1148         int ret = 0;
1149
1150         mutex_lock(&local->mtx);
1151
1152         if (!local->ops->sched_scan_stop) {
1153                 ret = -ENOTSUPP;
1154                 goto out;
1155         }
1156
1157         /* We don't want to restart sched scan anymore. */
1158         RCU_INIT_POINTER(local->sched_scan_req, NULL);
1159
1160         if (rcu_access_pointer(local->sched_scan_sdata)) {
1161                 ret = drv_sched_scan_stop(local, sdata);
1162                 if (!ret)
1163                         RCU_INIT_POINTER(local->sched_scan_sdata, NULL);
1164         }
1165 out:
1166         mutex_unlock(&local->mtx);
1167
1168         return ret;
1169 }
1170
1171 void ieee80211_sched_scan_results(struct ieee80211_hw *hw)
1172 {
1173         struct ieee80211_local *local = hw_to_local(hw);
1174
1175         trace_api_sched_scan_results(local);
1176
1177         cfg80211_sched_scan_results(hw->wiphy);
1178 }
1179 EXPORT_SYMBOL(ieee80211_sched_scan_results);
1180
1181 void ieee80211_sched_scan_end(struct ieee80211_local *local)
1182 {
1183         mutex_lock(&local->mtx);
1184
1185         if (!rcu_access_pointer(local->sched_scan_sdata)) {
1186                 mutex_unlock(&local->mtx);
1187                 return;
1188         }
1189
1190         RCU_INIT_POINTER(local->sched_scan_sdata, NULL);
1191
1192         /* If sched scan was aborted by the driver. */
1193         RCU_INIT_POINTER(local->sched_scan_req, NULL);
1194
1195         mutex_unlock(&local->mtx);
1196
1197         cfg80211_sched_scan_stopped(local->hw.wiphy);
1198 }
1199
1200 void ieee80211_sched_scan_stopped_work(struct work_struct *work)
1201 {
1202         struct ieee80211_local *local =
1203                 container_of(work, struct ieee80211_local,
1204                              sched_scan_stopped_work);
1205
1206         ieee80211_sched_scan_end(local);
1207 }
1208
1209 void ieee80211_sched_scan_stopped(struct ieee80211_hw *hw)
1210 {
1211         struct ieee80211_local *local = hw_to_local(hw);
1212
1213         trace_api_sched_scan_stopped(local);
1214
1215         schedule_work(&local->sched_scan_stopped_work);
1216 }
1217 EXPORT_SYMBOL(ieee80211_sched_scan_stopped);