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 <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         struct cfg80211_inform_bss bss_meta = {};
  70         bool signal_valid;
  71
  72         if (ieee80211_hw_check(&local->hw, SIGNAL_DBM))
  73                 bss_meta.signal = rx_status->signal * 100;
  74         else if (ieee80211_hw_check(&local->hw, SIGNAL_UNSPEC))
  75                 bss_meta.signal = (rx_status->signal * 100) / local->hw.max_signal;
  76
  77         bss_meta.scan_width = NL80211_BSS_CHAN_WIDTH_20;
  78         if (rx_status->flag & RX_FLAG_5MHZ)
  79                 bss_meta.scan_width = NL80211_BSS_CHAN_WIDTH_5;
  80         if (rx_status->flag & RX_FLAG_10MHZ)
  81                 bss_meta.scan_width = NL80211_BSS_CHAN_WIDTH_10;
  82
  83         bss_meta.chan = channel;
  84         cbss = cfg80211_inform_bss_frame_data(local->hw.wiphy, &bss_meta,
  85                                               mgmt, len, GFP_ATOMIC);
  86         if (!cbss)
  87                 return NULL;
  88         /* In case the signal is invalid update the status */
  89         signal_valid = abs(channel->center_freq - cbss->channel->center_freq)
  90                 <= local->hw.wiphy->max_adj_channel_rssi_comp;
  91         if (!signal_valid)
  92                 rx_status->flag |= RX_FLAG_NO_SIGNAL_VAL;
  93
  94         bss = (void *)cbss->priv;
  95
  96         if (beacon)
  97                 bss->device_ts_beacon = rx_status->device_timestamp;
  98         else
  99                 bss->device_ts_presp = rx_status->device_timestamp;
 100
 101         if (elems->parse_error) {
 102                 if (beacon)
 103                         bss->corrupt_data |= IEEE80211_BSS_CORRUPT_BEACON;
 104                 else
 105                         bss->corrupt_data |= IEEE80211_BSS_CORRUPT_PROBE_RESP;
 106         } else {
 107                 if (beacon)
 108                         bss->corrupt_data &= ~IEEE80211_BSS_CORRUPT_BEACON;
 109                 else
 110                         bss->corrupt_data &= ~IEEE80211_BSS_CORRUPT_PROBE_RESP;
 111         }
 112
 113         /* save the ERP value so that it is available at association time */
 114         if (elems->erp_info && (!elems->parse_error ||
 115                                 !(bss->valid_data & IEEE80211_BSS_VALID_ERP))) {
 116                 bss->erp_value = elems->erp_info[0];
 117                 bss->has_erp_value = true;
 118                 if (!elems->parse_error)
 119                         bss->valid_data |= IEEE80211_BSS_VALID_ERP;
 120         }
 121
 122         /* replace old supported rates if we get new values */
 123         if (!elems->parse_error ||
 124             !(bss->valid_data & IEEE80211_BSS_VALID_RATES)) {
 125                 srlen = 0;
 126                 if (elems->supp_rates) {
 127                         clen = IEEE80211_MAX_SUPP_RATES;
 128                         if (clen > elems->supp_rates_len)
 129                                 clen = elems->supp_rates_len;
 130                         memcpy(bss->supp_rates, elems->supp_rates, clen);
 131                         srlen += clen;
 132                 }
 133                 if (elems->ext_supp_rates) {
 134                         clen = IEEE80211_MAX_SUPP_RATES - srlen;
 135                         if (clen > elems->ext_supp_rates_len)
 136                                 clen = elems->ext_supp_rates_len;
 137                         memcpy(bss->supp_rates + srlen, elems->ext_supp_rates,
 138                                clen);
 139                         srlen += clen;
 140                 }
 141                 if (srlen) {
 142                         bss->supp_rates_len = srlen;
 143                         if (!elems->parse_error)
 144                                 bss->valid_data |= IEEE80211_BSS_VALID_RATES;
 145                 }
 146         }
 147
 148         if (!elems->parse_error ||
 149             !(bss->valid_data & IEEE80211_BSS_VALID_WMM)) {
 150                 bss->wmm_used = elems->wmm_param || elems->wmm_info;
 151                 bss->uapsd_supported = is_uapsd_supported(elems);
 152                 if (!elems->parse_error)
 153                         bss->valid_data |= IEEE80211_BSS_VALID_WMM;
 154         }
 155
 156         if (beacon) {
 157                 struct ieee80211_supported_band *sband =
 158                         local->hw.wiphy->bands[rx_status->band];
 159                 if (!(rx_status->flag & RX_FLAG_HT) &&
 160                     !(rx_status->flag & RX_FLAG_VHT))
 161                         bss->beacon_rate =
 162                                 &sband->bitrates[rx_status->rate_idx];
 163         }
 164
 165         return bss;
 166 }
 167
 168 void ieee80211_scan_rx(struct ieee80211_local *local, struct sk_buff *skb)
 169 {
 170         struct ieee80211_rx_status *rx_status = IEEE80211_SKB_RXCB(skb);
 171         struct ieee80211_sub_if_data *sdata1, *sdata2;
 172         struct ieee80211_mgmt *mgmt = (void *)skb->data;
 173         struct ieee80211_bss *bss;
 174         u8 *elements;
 175         struct ieee80211_channel *channel;
 176         size_t baselen;
 177         struct ieee802_11_elems elems;
 178
 179         if (skb->len < 24 ||
 180             (!ieee80211_is_probe_resp(mgmt->frame_control) &&
 181              !ieee80211_is_beacon(mgmt->frame_control)))
 182                 return;
 183
 184         sdata1 = rcu_dereference(local->scan_sdata);
 185         sdata2 = rcu_dereference(local->sched_scan_sdata);
 186
 187         if (likely(!sdata1 && !sdata2))
 188                 return;
 189
 190         if (ieee80211_is_probe_resp(mgmt->frame_control)) {
 191                 struct cfg80211_scan_request *scan_req;
 192                 struct cfg80211_sched_scan_request *sched_scan_req;
 193
 194                 scan_req = rcu_dereference(local->scan_req);
 195                 sched_scan_req = rcu_dereference(local->sched_scan_req);
 196
 197                 /* ignore ProbeResp to foreign address unless scanning
 198                  * with randomised address
 199                  */
 200                 if (!(sdata1 &&
 201                       (ether_addr_equal(mgmt->da, sdata1->vif.addr) ||
 202                        scan_req->flags & NL80211_SCAN_FLAG_RANDOM_ADDR)) &&
 203                     !(sdata2 &&
 204                       (ether_addr_equal(mgmt->da, sdata2->vif.addr) ||
 205                        sched_scan_req->flags & NL80211_SCAN_FLAG_RANDOM_ADDR)))
 206                         return;
 207
 208                 elements = mgmt->u.probe_resp.variable;
 209                 baselen = offsetof(struct ieee80211_mgmt, u.probe_resp.variable);
 210         } else {
 211                 baselen = offsetof(struct ieee80211_mgmt, u.beacon.variable);
 212                 elements = mgmt->u.beacon.variable;
 213         }
 214
 215         if (baselen > skb->len)
 216                 return;
 217
 218         ieee802_11_parse_elems(elements, skb->len - baselen, false, &elems);
 219
 220         channel = ieee80211_get_channel(local->hw.wiphy, rx_status->freq);
 221
 222         if (!channel || channel->flags & IEEE80211_CHAN_DISABLED)
 223                 return;
 224
 225         bss = ieee80211_bss_info_update(local, rx_status,
 226                                         mgmt, skb->len, &elems,
 227                                         channel);
 228         if (bss)
 229                 ieee80211_rx_bss_put(local, bss);
 230 }
 231
 232 static void
 233 ieee80211_prepare_scan_chandef(struct cfg80211_chan_def *chandef,
 234                                enum nl80211_bss_scan_width scan_width)
 235 {
 236         memset(chandef, 0, sizeof(*chandef));
 237         switch (scan_width) {
 238         case NL80211_BSS_CHAN_WIDTH_5:
 239                 chandef->width = NL80211_CHAN_WIDTH_5;
 240                 break;
 241         case NL80211_BSS_CHAN_WIDTH_10:
 242                 chandef->width = NL80211_CHAN_WIDTH_10;
 243                 break;
 244         default:
 245                 chandef->width = NL80211_CHAN_WIDTH_20_NOHT;
 246                 break;
 247         }
 248 }
 249
 250 /* return false if no more work */
 251 static bool ieee80211_prep_hw_scan(struct ieee80211_local *local)
 252 {
 253         struct cfg80211_scan_request *req;
 254         struct cfg80211_chan_def chandef;
 255         u8 bands_used = 0;
 256         int i, ielen, n_chans;
 257
 258         req = rcu_dereference_protected(local->scan_req,
 259                                         lockdep_is_held(&local->mtx));
 260
 261         if (test_bit(SCAN_HW_CANCELLED, &local->scanning))
 262                 return false;
 263
 264         if (ieee80211_hw_check(&local->hw, SINGLE_SCAN_ON_ALL_BANDS)) {
 265                 for (i = 0; i < req->n_channels; i++) {
 266                         local->hw_scan_req->req.channels[i] = req->channels[i];
 267                         bands_used |= BIT(req->channels[i]->band);
 268                 }
 269
 270                 n_chans = req->n_channels;
 271         } else {
 272                 do {
 273                         if (local->hw_scan_band == IEEE80211_NUM_BANDS)
 274                                 return false;
 275
 276                         n_chans = 0;
 277
 278                         for (i = 0; i < req->n_channels; i++) {
 279                                 if (req->channels[i]->band !=
 280                                     local->hw_scan_band)
 281                                         continue;
 282                                 local->hw_scan_req->req.channels[n_chans] =
 283                                                         req->channels[i];
 284                                 n_chans++;
 285                                 bands_used |= BIT(req->channels[i]->band);
 286                         }
 287
 288                         local->hw_scan_band++;
 289                 } while (!n_chans);
 290         }
 291
 292         local->hw_scan_req->req.n_channels = n_chans;
 293         ieee80211_prepare_scan_chandef(&chandef, req->scan_width);
 294
 295         ielen = ieee80211_build_preq_ies(local,
 296                                          (u8 *)local->hw_scan_req->req.ie,
 297                                          local->hw_scan_ies_bufsize,
 298                                          &local->hw_scan_req->ies,
 299                                          req->ie, req->ie_len,
 300                                          bands_used, req->rates, &chandef);
 301         local->hw_scan_req->req.ie_len = ielen;
 302         local->hw_scan_req->req.no_cck = req->no_cck;
 303         ether_addr_copy(local->hw_scan_req->req.mac_addr, req->mac_addr);
 304         ether_addr_copy(local->hw_scan_req->req.mac_addr_mask,
 305                         req->mac_addr_mask);
 306
 307         return true;
 308 }
 309
 310 static void __ieee80211_scan_completed(struct ieee80211_hw *hw, bool aborted)
 311 {
 312         struct ieee80211_local *local = hw_to_local(hw);
 313         bool hw_scan = local->ops->hw_scan;
 314         bool was_scanning = local->scanning;
 315         struct cfg80211_scan_request *scan_req;
 316         struct ieee80211_sub_if_data *scan_sdata;
 317
 318         lockdep_assert_held(&local->mtx);
 319
 320         /*
 321          * It's ok to abort a not-yet-running scan (that
 322          * we have one at all will be verified by checking
 323          * local->scan_req next), but not to complete it
 324          * successfully.
 325          */
 326         if (WARN_ON(!local->scanning && !aborted))
 327                 aborted = true;
 328
 329         if (WARN_ON(!local->scan_req))
 330                 return;
 331
 332         if (hw_scan && !aborted &&
 333             !ieee80211_hw_check(&local->hw, SINGLE_SCAN_ON_ALL_BANDS) &&
 334             ieee80211_prep_hw_scan(local)) {
 335                 int rc;
 336
 337                 rc = drv_hw_scan(local,
 338                         rcu_dereference_protected(local->scan_sdata,
 339                                                   lockdep_is_held(&local->mtx)),
 340                         local->hw_scan_req);
 341
 342                 if (rc == 0)
 343                         return;
 344         }
 345
 346         kfree(local->hw_scan_req);
 347         local->hw_scan_req = NULL;
 348
 349         scan_req = rcu_dereference_protected(local->scan_req,
 350                                              lockdep_is_held(&local->mtx));
 351
 352         if (scan_req != local->int_scan_req)
 353                 cfg80211_scan_done(scan_req, aborted);
 354         RCU_INIT_POINTER(local->scan_req, NULL);
 355
 356         scan_sdata = rcu_dereference_protected(local->scan_sdata,
 357                                                lockdep_is_held(&local->mtx));
 358         RCU_INIT_POINTER(local->scan_sdata, NULL);
 359
 360         local->scanning = 0;
 361         local->scan_chandef.chan = NULL;
 362
 363         /* Set power back to normal operating levels. */
 364         ieee80211_hw_config(local, 0);
 365
 366         if (!hw_scan) {
 367                 ieee80211_configure_filter(local);
 368                 drv_sw_scan_complete(local, scan_sdata);
 369                 ieee80211_offchannel_return(local);
 370         }
 371
 372         ieee80211_recalc_idle(local);
 373
 374         ieee80211_mlme_notify_scan_completed(local);
 375         ieee80211_ibss_notify_scan_completed(local);
 376         ieee80211_mesh_notify_scan_completed(local);
 377         if (was_scanning)
 378                 ieee80211_start_next_roc(local);
 379 }
 380
 381 void ieee80211_scan_completed(struct ieee80211_hw *hw, bool aborted)
 382 {
 383         struct ieee80211_local *local = hw_to_local(hw);
 384
 385         trace_api_scan_completed(local, aborted);
 386
 387         set_bit(SCAN_COMPLETED, &local->scanning);
 388         if (aborted)
 389                 set_bit(SCAN_ABORTED, &local->scanning);
 390         ieee80211_queue_delayed_work(&local->hw, &local->scan_work, 0);
 391 }
 392 EXPORT_SYMBOL(ieee80211_scan_completed);
 393
 394 static int ieee80211_start_sw_scan(struct ieee80211_local *local,
 395                                    struct ieee80211_sub_if_data *sdata)
 396 {
 397         /* Software scan is not supported in multi-channel cases */
 398         if (local->use_chanctx)
 399                 return -EOPNOTSUPP;
 400
 401         /*
 402          * Hardware/driver doesn't support hw_scan, so use software
 403          * scanning instead. First send a nullfunc frame with power save
 404          * bit on so that AP will buffer the frames for us while we are not
 405          * listening, then send probe requests to each channel and wait for
 406          * the responses. After all channels are scanned, tune back to the
 407          * original channel and send a nullfunc frame with power save bit
 408          * off to trigger the AP to send us all the buffered frames.
 409          *
 410          * Note that while local->sw_scanning is true everything else but
 411          * nullfunc frames and probe requests will be dropped in
 412          * ieee80211_tx_h_check_assoc().
 413          */
 414         drv_sw_scan_start(local, sdata, local->scan_addr);
 415
 416         local->leave_oper_channel_time = jiffies;
 417         local->next_scan_state = SCAN_DECISION;
 418         local->scan_channel_idx = 0;
 419
 420         ieee80211_offchannel_stop_vifs(local);
 421
 422         /* ensure nullfunc is transmitted before leaving operating channel */
 423         ieee80211_flush_queues(local, NULL, false);
 424
 425         ieee80211_configure_filter(local);
 426
 427         /* We need to set power level at maximum rate for scanning. */
 428         ieee80211_hw_config(local, 0);
 429
 430         ieee80211_queue_delayed_work(&local->hw,
 431                                      &local->scan_work, 0);
 432
 433         return 0;
 434 }
 435
 436 static bool ieee80211_can_scan(struct ieee80211_local *local,
 437                                struct ieee80211_sub_if_data *sdata)
 438 {
 439         if (ieee80211_is_radar_required(local))
 440                 return false;
 441
 442         if (!list_empty(&local->roc_list))
 443                 return false;
 444
 445         if (sdata->vif.type == NL80211_IFTYPE_STATION &&
 446             sdata->u.mgd.flags & IEEE80211_STA_CONNECTION_POLL)
 447                 return false;
 448
 449         return true;
 450 }
 451
 452 void ieee80211_run_deferred_scan(struct ieee80211_local *local)
 453 {
 454         lockdep_assert_held(&local->mtx);
 455
 456         if (!local->scan_req || local->scanning)
 457                 return;
 458
 459         if (!ieee80211_can_scan(local,
 460                                 rcu_dereference_protected(
 461                                         local->scan_sdata,
 462                                         lockdep_is_held(&local->mtx))))
 463                 return;
 464
 465         ieee80211_queue_delayed_work(&local->hw, &local->scan_work,
 466                                      round_jiffies_relative(0));
 467 }
 468
 469 static void ieee80211_scan_state_send_probe(struct ieee80211_local *local,
 470                                             unsigned long *next_delay)
 471 {
 472         int i;
 473         struct ieee80211_sub_if_data *sdata;
 474         struct cfg80211_scan_request *scan_req;
 475         enum ieee80211_band band = local->hw.conf.chandef.chan->band;
 476         u32 tx_flags;
 477
 478         scan_req = rcu_dereference_protected(local->scan_req,
 479                                              lockdep_is_held(&local->mtx));
 480
 481         tx_flags = IEEE80211_TX_INTFL_OFFCHAN_TX_OK;
 482         if (scan_req->no_cck)
 483                 tx_flags |= IEEE80211_TX_CTL_NO_CCK_RATE;
 484
 485         sdata = rcu_dereference_protected(local->scan_sdata,
 486                                           lockdep_is_held(&local->mtx));
 487
 488         for (i = 0; i < scan_req->n_ssids; i++)
 489                 ieee80211_send_probe_req(
 490                         sdata, local->scan_addr, NULL,
 491                         scan_req->ssids[i].ssid, scan_req->ssids[i].ssid_len,
 492                         scan_req->ie, scan_req->ie_len,
 493                         scan_req->rates[band], false,
 494                         tx_flags, local->hw.conf.chandef.chan, true);
 495
 496         /*
 497          * After sending probe requests, wait for probe responses
 498          * on the channel.
 499          */
 500         *next_delay = IEEE80211_CHANNEL_TIME;
 501         local->next_scan_state = SCAN_DECISION;
 502 }
 503
 504 static int __ieee80211_start_scan(struct ieee80211_sub_if_data *sdata,
 505                                   struct cfg80211_scan_request *req)
 506 {
 507         struct ieee80211_local *local = sdata->local;
 508         int rc;
 509
 510         lockdep_assert_held(&local->mtx);
 511
 512         if (local->scan_req || ieee80211_is_radar_required(local))
 513                 return -EBUSY;
 514
 515         if (!ieee80211_can_scan(local, sdata)) {
 516                 /* wait for the work to finish/time out */
 517                 rcu_assign_pointer(local->scan_req, req);
 518                 rcu_assign_pointer(local->scan_sdata, sdata);
 519                 return 0;
 520         }
 521
 522         if (local->ops->hw_scan) {
 523                 u8 *ies;
 524
 525                 local->hw_scan_ies_bufsize = local->scan_ies_len + req->ie_len;
 526
 527                 if (ieee80211_hw_check(&local->hw, SINGLE_SCAN_ON_ALL_BANDS)) {
 528                         int i, n_bands = 0;
 529                         u8 bands_counted = 0;
 530
 531                         for (i = 0; i < req->n_channels; i++) {
 532                                 if (bands_counted & BIT(req->channels[i]->band))
 533                                         continue;
 534                                 bands_counted |= BIT(req->channels[i]->band);
 535                                 n_bands++;
 536                         }
 537
 538                         local->hw_scan_ies_bufsize *= n_bands;
 539                 }
 540
 541                 local->hw_scan_req = kmalloc(
 542                                 sizeof(*local->hw_scan_req) +
 543                                 req->n_channels * sizeof(req->channels[0]) +
 544                                 local->hw_scan_ies_bufsize, GFP_KERNEL);
 545                 if (!local->hw_scan_req)
 546                         return -ENOMEM;
 547
 548                 local->hw_scan_req->req.ssids = req->ssids;
 549                 local->hw_scan_req->req.n_ssids = req->n_ssids;
 550                 ies = (u8 *)local->hw_scan_req +
 551                         sizeof(*local->hw_scan_req) +
 552                         req->n_channels * sizeof(req->channels[0]);
 553                 local->hw_scan_req->req.ie = ies;
 554                 local->hw_scan_req->req.flags = req->flags;
 555
 556                 local->hw_scan_band = 0;
 557
 558                 /*
 559                  * After allocating local->hw_scan_req, we must
 560                  * go through until ieee80211_prep_hw_scan(), so
 561                  * anything that might be changed here and leave
 562                  * this function early must not go after this
 563                  * allocation.
 564                  */
 565         }
 566
 567         rcu_assign_pointer(local->scan_req, req);
 568         rcu_assign_pointer(local->scan_sdata, sdata);
 569
 570         if (req->flags & NL80211_SCAN_FLAG_RANDOM_ADDR)
 571                 get_random_mask_addr(local->scan_addr,
 572                                      req->mac_addr,
 573                                      req->mac_addr_mask);
 574         else
 575                 memcpy(local->scan_addr, sdata->vif.addr, ETH_ALEN);
 576
 577         if (local->ops->hw_scan) {
 578                 __set_bit(SCAN_HW_SCANNING, &local->scanning);
 579         } else if ((req->n_channels == 1) &&
 580                    (req->channels[0] == local->_oper_chandef.chan)) {
 581                 /*
 582                  * If we are scanning only on the operating channel
 583                  * then we do not need to stop normal activities
 584                  */
 585                 unsigned long next_delay;
 586
 587                 __set_bit(SCAN_ONCHANNEL_SCANNING, &local->scanning);
 588
 589                 ieee80211_recalc_idle(local);
 590
 591                 /* Notify driver scan is starting, keep order of operations
 592                  * same as normal software scan, in case that matters. */
 593                 drv_sw_scan_start(local, sdata, local->scan_addr);
 594
 595                 ieee80211_configure_filter(local); /* accept probe-responses */
 596
 597                 /* We need to ensure power level is at max for scanning. */
 598                 ieee80211_hw_config(local, 0);
 599
 600                 if ((req->channels[0]->flags & (IEEE80211_CHAN_NO_IR |
 601                                                 IEEE80211_CHAN_RADAR)) ||
 602                     !req->n_ssids) {
 603                         next_delay = IEEE80211_PASSIVE_CHANNEL_TIME;
 604                 } else {
 605                         ieee80211_scan_state_send_probe(local, &next_delay);
 606                         next_delay = IEEE80211_CHANNEL_TIME;
 607                 }
 608
 609                 /* Now, just wait a bit and we are all done! */
 610                 ieee80211_queue_delayed_work(&local->hw, &local->scan_work,
 611                                              next_delay);
 612                 return 0;
 613         } else {
 614                 /* Do normal software scan */
 615                 __set_bit(SCAN_SW_SCANNING, &local->scanning);
 616         }
 617
 618         ieee80211_recalc_idle(local);
 619
 620         if (local->ops->hw_scan) {
 621                 WARN_ON(!ieee80211_prep_hw_scan(local));
 622                 rc = drv_hw_scan(local, sdata, local->hw_scan_req);
 623         } else {
 624                 rc = ieee80211_start_sw_scan(local, sdata);
 625         }
 626
 627         if (rc) {
 628                 kfree(local->hw_scan_req);
 629                 local->hw_scan_req = NULL;
 630                 local->scanning = 0;
 631
 632                 ieee80211_recalc_idle(local);
 633
 634                 local->scan_req = NULL;
 635                 RCU_INIT_POINTER(local->scan_sdata, NULL);
 636         }
 637
 638         return rc;
 639 }
 640
 641 static unsigned long
 642 ieee80211_scan_get_channel_time(struct ieee80211_channel *chan)
 643 {
 644         /*
 645          * TODO: channel switching also consumes quite some time,
 646          * add that delay as well to get a better estimation
 647          */
 648         if (chan->flags & (IEEE80211_CHAN_NO_IR | IEEE80211_CHAN_RADAR))
 649                 return IEEE80211_PASSIVE_CHANNEL_TIME;
 650         return IEEE80211_PROBE_DELAY + IEEE80211_CHANNEL_TIME;
 651 }
 652
 653 static void ieee80211_scan_state_decision(struct ieee80211_local *local,
 654                                           unsigned long *next_delay)
 655 {
 656         bool associated = false;
 657         bool tx_empty = true;
 658         bool bad_latency;
 659         struct ieee80211_sub_if_data *sdata;
 660         struct ieee80211_channel *next_chan;
 661         enum mac80211_scan_state next_scan_state;
 662         struct cfg80211_scan_request *scan_req;
 663
 664         /*
 665          * check if at least one STA interface is associated,
 666          * check if at least one STA interface has pending tx frames
 667          * and grab the lowest used beacon interval
 668          */
 669         mutex_lock(&local->iflist_mtx);
 670         list_for_each_entry(sdata, &local->interfaces, list) {
 671                 if (!ieee80211_sdata_running(sdata))
 672                         continue;
 673
 674                 if (sdata->vif.type == NL80211_IFTYPE_STATION) {
 675                         if (sdata->u.mgd.associated) {
 676                                 associated = true;
 677
 678                                 if (!qdisc_all_tx_empty(sdata->dev)) {
 679                                         tx_empty = false;
 680                                         break;
 681                                 }
 682                         }
 683                 }
 684         }
 685         mutex_unlock(&local->iflist_mtx);
 686
 687         scan_req = rcu_dereference_protected(local->scan_req,
 688                                              lockdep_is_held(&local->mtx));
 689
 690         next_chan = scan_req->channels[local->scan_channel_idx];
 691
 692         /*
 693          * we're currently scanning a different channel, let's
 694          * see if we can scan another channel without interfering
 695          * with the current traffic situation.
 696          *
 697          * Keep good latency, do not stay off-channel more than 125 ms.
 698          */
 699
 700         bad_latency = time_after(jiffies +
 701                                  ieee80211_scan_get_channel_time(next_chan),
 702                                  local->leave_oper_channel_time + HZ / 8);
 703
 704         if (associated && !tx_empty) {
 705                 if (scan_req->flags & NL80211_SCAN_FLAG_LOW_PRIORITY)
 706                         next_scan_state = SCAN_ABORT;
 707                 else
 708                         next_scan_state = SCAN_SUSPEND;
 709         } else if (associated && bad_latency) {
 710                 next_scan_state = SCAN_SUSPEND;
 711         } else {
 712                 next_scan_state = SCAN_SET_CHANNEL;
 713         }
 714
 715         local->next_scan_state = next_scan_state;
 716
 717         *next_delay = 0;
 718 }
 719
 720 static void ieee80211_scan_state_set_channel(struct ieee80211_local *local,
 721                                              unsigned long *next_delay)
 722 {
 723         int skip;
 724         struct ieee80211_channel *chan;
 725         enum nl80211_bss_scan_width oper_scan_width;
 726         struct cfg80211_scan_request *scan_req;
 727
 728         scan_req = rcu_dereference_protected(local->scan_req,
 729                                              lockdep_is_held(&local->mtx));
 730
 731         skip = 0;
 732         chan = scan_req->channels[local->scan_channel_idx];
 733
 734         local->scan_chandef.chan = chan;
 735         local->scan_chandef.center_freq1 = chan->center_freq;
 736         local->scan_chandef.center_freq2 = 0;
 737         switch (scan_req->scan_width) {
 738         case NL80211_BSS_CHAN_WIDTH_5:
 739                 local->scan_chandef.width = NL80211_CHAN_WIDTH_5;
 740                 break;
 741         case NL80211_BSS_CHAN_WIDTH_10:
 742                 local->scan_chandef.width = NL80211_CHAN_WIDTH_10;
 743                 break;
 744         case NL80211_BSS_CHAN_WIDTH_20:
 745                 /* If scanning on oper channel, use whatever channel-type
 746                  * is currently in use.
 747                  */
 748                 oper_scan_width = cfg80211_chandef_to_scan_width(
 749                                         &local->_oper_chandef);
 750                 if (chan == local->_oper_chandef.chan &&
 751                     oper_scan_width == scan_req->scan_width)
 752                         local->scan_chandef = local->_oper_chandef;
 753                 else
 754                         local->scan_chandef.width = NL80211_CHAN_WIDTH_20_NOHT;
 755                 break;
 756         }
 757
 758         if (ieee80211_hw_config(local, IEEE80211_CONF_CHANGE_CHANNEL))
 759                 skip = 1;
 760
 761         /* advance state machine to next channel/band */
 762         local->scan_channel_idx++;
 763
 764         if (skip) {
 765                 /* if we skip this channel return to the decision state */
 766                 local->next_scan_state = SCAN_DECISION;
 767                 return;
 768         }
 769
 770         /*
 771          * Probe delay is used to update the NAV, cf. 11.1.3.2.2
 772          * (which unfortunately doesn't say _why_ step a) is done,
 773          * but it waits for the probe delay or until a frame is
 774          * received - and the received frame would update the NAV).
 775          * For now, we do not support waiting until a frame is
 776          * received.
 777          *
 778          * In any case, it is not necessary for a passive scan.
 779          */
 780         if ((chan->flags & (IEEE80211_CHAN_NO_IR | IEEE80211_CHAN_RADAR)) ||
 781             !scan_req->n_ssids) {
 782                 *next_delay = IEEE80211_PASSIVE_CHANNEL_TIME;
 783                 local->next_scan_state = SCAN_DECISION;
 784                 return;
 785         }
 786
 787         /* active scan, send probes */
 788         *next_delay = IEEE80211_PROBE_DELAY;
 789         local->next_scan_state = SCAN_SEND_PROBE;
 790 }
 791
 792 static void ieee80211_scan_state_suspend(struct ieee80211_local *local,
 793                                          unsigned long *next_delay)
 794 {
 795         /* switch back to the operating channel */
 796         local->scan_chandef.chan = NULL;
 797         ieee80211_hw_config(local, IEEE80211_CONF_CHANGE_CHANNEL);
 798
 799         /* disable PS */
 800         ieee80211_offchannel_return(local);
 801
 802         *next_delay = HZ / 5;
 803         /* afterwards, resume scan & go to next channel */
 804         local->next_scan_state = SCAN_RESUME;
 805 }
 806
 807 static void ieee80211_scan_state_resume(struct ieee80211_local *local,
 808                                         unsigned long *next_delay)
 809 {
 810         ieee80211_offchannel_stop_vifs(local);
 811
 812         if (local->ops->flush) {
 813                 ieee80211_flush_queues(local, NULL, false);
 814                 *next_delay = 0;
 815         } else
 816                 *next_delay = HZ / 10;
 817
 818         /* remember when we left the operating channel */
 819         local->leave_oper_channel_time = jiffies;
 820
 821         /* advance to the next channel to be scanned */
 822         local->next_scan_state = SCAN_SET_CHANNEL;
 823 }
 824
 825 void ieee80211_scan_work(struct work_struct *work)
 826 {
 827         struct ieee80211_local *local =
 828                 container_of(work, struct ieee80211_local, scan_work.work);
 829         struct ieee80211_sub_if_data *sdata;
 830         struct cfg80211_scan_request *scan_req;
 831         unsigned long next_delay = 0;
 832         bool aborted;
 833
 834         mutex_lock(&local->mtx);
 835
 836         if (!ieee80211_can_run_worker(local)) {
 837                 aborted = true;
 838                 goto out_complete;
 839         }
 840
 841         sdata = rcu_dereference_protected(local->scan_sdata,
 842                                           lockdep_is_held(&local->mtx));
 843         scan_req = rcu_dereference_protected(local->scan_req,
 844                                              lockdep_is_held(&local->mtx));
 845
 846         /* When scanning on-channel, the first-callback means completed. */
 847         if (test_bit(SCAN_ONCHANNEL_SCANNING, &local->scanning)) {
 848                 aborted = test_and_clear_bit(SCAN_ABORTED, &local->scanning);
 849                 goto out_complete;
 850         }
 851
 852         if (test_and_clear_bit(SCAN_COMPLETED, &local->scanning)) {
 853                 aborted = test_and_clear_bit(SCAN_ABORTED, &local->scanning);
 854                 goto out_complete;
 855         }
 856
 857         if (!sdata || !scan_req)
 858                 goto out;
 859
 860         if (!local->scanning) {
 861                 int rc;
 862
 863                 RCU_INIT_POINTER(local->scan_req, NULL);
 864                 RCU_INIT_POINTER(local->scan_sdata, NULL);
 865
 866                 rc = __ieee80211_start_scan(sdata, scan_req);
 867                 if (rc) {
 868                         /* need to complete scan in cfg80211 */
 869                         rcu_assign_pointer(local->scan_req, scan_req);
 870                         aborted = true;
 871                         goto out_complete;
 872                 } else
 873                         goto out;
 874         }
 875
 876         /*
 877          * as long as no delay is required advance immediately
 878          * without scheduling a new work
 879          */
 880         do {
 881                 if (!ieee80211_sdata_running(sdata)) {
 882                         aborted = true;
 883                         goto out_complete;
 884                 }
 885
 886                 switch (local->next_scan_state) {
 887                 case SCAN_DECISION:
 888                         /* if no more bands/channels left, complete scan */
 889                         if (local->scan_channel_idx >= scan_req->n_channels) {
 890                                 aborted = false;
 891                                 goto out_complete;
 892                         }
 893                         ieee80211_scan_state_decision(local, &next_delay);
 894                         break;
 895                 case SCAN_SET_CHANNEL:
 896                         ieee80211_scan_state_set_channel(local, &next_delay);
 897                         break;
 898                 case SCAN_SEND_PROBE:
 899                         ieee80211_scan_state_send_probe(local, &next_delay);
 900                         break;
 901                 case SCAN_SUSPEND:
 902                         ieee80211_scan_state_suspend(local, &next_delay);
 903                         break;
 904                 case SCAN_RESUME:
 905                         ieee80211_scan_state_resume(local, &next_delay);
 906                         break;
 907                 case SCAN_ABORT:
 908                         aborted = true;
 909                         goto out_complete;
 910                 }
 911         } while (next_delay == 0);
 912
 913         ieee80211_queue_delayed_work(&local->hw, &local->scan_work, next_delay);
 914         goto out;
 915
 916 out_complete:
 917         __ieee80211_scan_completed(&local->hw, aborted);
 918 out:
 919         mutex_unlock(&local->mtx);
 920 }
 921
 922 int ieee80211_request_scan(struct ieee80211_sub_if_data *sdata,
 923                            struct cfg80211_scan_request *req)
 924 {
 925         int res;
 926
 927         mutex_lock(&sdata->local->mtx);
 928         res = __ieee80211_start_scan(sdata, req);
 929         mutex_unlock(&sdata->local->mtx);
 930
 931         return res;
 932 }
 933
 934 int ieee80211_request_ibss_scan(struct ieee80211_sub_if_data *sdata,
 935                                 const u8 *ssid, u8 ssid_len,
 936                                 struct ieee80211_channel **channels,
 937                                 unsigned int n_channels,
 938                                 enum nl80211_bss_scan_width scan_width)
 939 {
 940         struct ieee80211_local *local = sdata->local;
 941         int ret = -EBUSY, i, n_ch = 0;
 942         enum ieee80211_band band;
 943
 944         mutex_lock(&local->mtx);
 945
 946         /* busy scanning */
 947         if (local->scan_req)
 948                 goto unlock;
 949
 950         /* fill internal scan request */
 951         if (!channels) {
 952                 int max_n;
 953
 954                 for (band = 0; band < IEEE80211_NUM_BANDS; band++) {
 955                         if (!local->hw.wiphy->bands[band])
 956                                 continue;
 957
 958                         max_n = local->hw.wiphy->bands[band]->n_channels;
 959                         for (i = 0; i < max_n; i++) {
 960                                 struct ieee80211_channel *tmp_ch =
 961                                     &local->hw.wiphy->bands[band]->channels[i];
 962
 963                                 if (tmp_ch->flags & (IEEE80211_CHAN_NO_IR |
 964                                                      IEEE80211_CHAN_DISABLED))
 965                                         continue;
 966
 967                                 local->int_scan_req->channels[n_ch] = tmp_ch;
 968                                 n_ch++;
 969                         }
 970                 }
 971
 972                 if (WARN_ON_ONCE(n_ch == 0))
 973                         goto unlock;
 974
 975                 local->int_scan_req->n_channels = n_ch;
 976         } else {
 977                 for (i = 0; i < n_channels; i++) {
 978                         if (channels[i]->flags & (IEEE80211_CHAN_NO_IR |
 979                                                   IEEE80211_CHAN_DISABLED))
 980                                 continue;
 981
 982                         local->int_scan_req->channels[n_ch] = channels[i];
 983                         n_ch++;
 984                 }
 985
 986                 if (WARN_ON_ONCE(n_ch == 0))
 987                         goto unlock;
 988
 989                 local->int_scan_req->n_channels = n_ch;
 990         }
 991
 992         local->int_scan_req->ssids = &local->scan_ssid;
 993         local->int_scan_req->n_ssids = 1;
 994         local->int_scan_req->scan_width = scan_width;
 995         memcpy(local->int_scan_req->ssids[0].ssid, ssid, IEEE80211_MAX_SSID_LEN);
 996         local->int_scan_req->ssids[0].ssid_len = ssid_len;
 997
 998         ret = __ieee80211_start_scan(sdata, sdata->local->int_scan_req);
 999  unlock:
1000         mutex_unlock(&local->mtx);
1001         return ret;
1002 }
1003
1004 /*
1005  * Only call this function when a scan can't be queued -- under RTNL.
1006  */
1007 void ieee80211_scan_cancel(struct ieee80211_local *local)
1008 {
1009         /*
1010          * We are canceling software scan, or deferred scan that was not
1011          * yet really started (see __ieee80211_start_scan ).
1012          *
1013          * Regarding hardware scan:
1014          * - we can not call  __ieee80211_scan_completed() as when
1015          *   SCAN_HW_SCANNING bit is set this function change
1016          *   local->hw_scan_req to operate on 5G band, what race with
1017          *   driver which can use local->hw_scan_req
1018          *
1019          * - we can not cancel scan_work since driver can schedule it
1020          *   by ieee80211_scan_completed(..., true) to finish scan
1021          *
1022          * Hence we only call the cancel_hw_scan() callback, but the low-level
1023          * driver is still responsible for calling ieee80211_scan_completed()
1024          * after the scan was completed/aborted.
1025          */
1026
1027         mutex_lock(&local->mtx);
1028         if (!local->scan_req)
1029                 goto out;
1030
1031         /*
1032          * We have a scan running and the driver already reported completion,
1033          * but the worker hasn't run yet or is stuck on the mutex - mark it as
1034          * cancelled.
1035          */
1036         if (test_bit(SCAN_HW_SCANNING, &local->scanning) &&
1037             test_bit(SCAN_COMPLETED, &local->scanning)) {
1038                 set_bit(SCAN_HW_CANCELLED, &local->scanning);
1039                 goto out;
1040         }
1041
1042         if (test_bit(SCAN_HW_SCANNING, &local->scanning)) {
1043                 /*
1044                  * Make sure that __ieee80211_scan_completed doesn't trigger a
1045                  * scan on another band.
1046                  */
1047                 set_bit(SCAN_HW_CANCELLED, &local->scanning);
1048                 if (local->ops->cancel_hw_scan)
1049                         drv_cancel_hw_scan(local,
1050                                 rcu_dereference_protected(local->scan_sdata,
1051                                                 lockdep_is_held(&local->mtx)));
1052                 goto out;
1053         }
1054
1055         /*
1056          * If the work is currently running, it must be blocked on
1057          * the mutex, but we'll set scan_sdata = NULL and it'll
1058          * simply exit once it acquires the mutex.
1059          */
1060         cancel_delayed_work(&local->scan_work);
1061         /* and clean up */
1062         __ieee80211_scan_completed(&local->hw, true);
1063 out:
1064         mutex_unlock(&local->mtx);
1065 }
1066
1067 int __ieee80211_request_sched_scan_start(struct ieee80211_sub_if_data *sdata,
1068                                         struct cfg80211_sched_scan_request *req)
1069 {
1070         struct ieee80211_local *local = sdata->local;
1071         struct ieee80211_scan_ies sched_scan_ies = {};
1072         struct cfg80211_chan_def chandef;
1073         int ret, i, iebufsz, num_bands = 0;
1074         u32 rate_masks[IEEE80211_NUM_BANDS] = {};
1075         u8 bands_used = 0;
1076         u8 *ie;
1077         size_t len;
1078
1079         iebufsz = local->scan_ies_len + req->ie_len;
1080
1081         lockdep_assert_held(&local->mtx);
1082
1083         if (!local->ops->sched_scan_start)
1084                 return -ENOTSUPP;
1085
1086         for (i = 0; i < IEEE80211_NUM_BANDS; i++) {
1087                 if (local->hw.wiphy->bands[i]) {
1088                         bands_used |= BIT(i);
1089                         rate_masks[i] = (u32) -1;
1090                         num_bands++;
1091                 }
1092         }
1093
1094         ie = kzalloc(num_bands * iebufsz, GFP_KERNEL);
1095         if (!ie) {
1096                 ret = -ENOMEM;
1097                 goto out;
1098         }
1099
1100         ieee80211_prepare_scan_chandef(&chandef, req->scan_width);
1101
1102         len = ieee80211_build_preq_ies(local, ie, num_bands * iebufsz,
1103                                        &sched_scan_ies, req->ie,
1104                                        req->ie_len, bands_used,
1105                                        rate_masks, &chandef);
1106
1107         ret = drv_sched_scan_start(local, sdata, req, &sched_scan_ies);
1108         if (ret == 0) {
1109                 rcu_assign_pointer(local->sched_scan_sdata, sdata);
1110                 rcu_assign_pointer(local->sched_scan_req, req);
1111         }
1112
1113         kfree(ie);
1114
1115 out:
1116         if (ret) {
1117                 /* Clean in case of failure after HW restart or upon resume. */
1118                 RCU_INIT_POINTER(local->sched_scan_sdata, NULL);
1119                 RCU_INIT_POINTER(local->sched_scan_req, NULL);
1120         }
1121
1122         return ret;
1123 }
1124
1125 int ieee80211_request_sched_scan_start(struct ieee80211_sub_if_data *sdata,
1126                                        struct cfg80211_sched_scan_request *req)
1127 {
1128         struct ieee80211_local *local = sdata->local;
1129         int ret;
1130
1131         mutex_lock(&local->mtx);
1132
1133         if (rcu_access_pointer(local->sched_scan_sdata)) {
1134                 mutex_unlock(&local->mtx);
1135                 return -EBUSY;
1136         }
1137
1138         ret = __ieee80211_request_sched_scan_start(sdata, req);
1139
1140         mutex_unlock(&local->mtx);
1141         return ret;
1142 }
1143
1144 int ieee80211_request_sched_scan_stop(struct ieee80211_local *local)
1145 {
1146         struct ieee80211_sub_if_data *sched_scan_sdata;
1147         int ret = -ENOENT;
1148
1149         mutex_lock(&local->mtx);
1150
1151         if (!local->ops->sched_scan_stop) {
1152                 ret = -ENOTSUPP;
1153                 goto out;
1154         }
1155
1156         /* We don't want to restart sched scan anymore. */
1157         RCU_INIT_POINTER(local->sched_scan_req, NULL);
1158
1159         sched_scan_sdata = rcu_dereference_protected(local->sched_scan_sdata,
1160                                                 lockdep_is_held(&local->mtx));
1161         if (sched_scan_sdata) {
1162                 ret = drv_sched_scan_stop(local, sched_scan_sdata);
1163                 if (!ret)
1164                         RCU_INIT_POINTER(local->sched_scan_sdata, NULL);
1165         }
1166 out:
1167         mutex_unlock(&local->mtx);
1168
1169         return ret;
1170 }
1171
1172 void ieee80211_sched_scan_results(struct ieee80211_hw *hw)
1173 {
1174         struct ieee80211_local *local = hw_to_local(hw);
1175
1176         trace_api_sched_scan_results(local);
1177
1178         cfg80211_sched_scan_results(hw->wiphy);
1179 }
1180 EXPORT_SYMBOL(ieee80211_sched_scan_results);
1181
1182 void ieee80211_sched_scan_end(struct ieee80211_local *local)
1183 {
1184         mutex_lock(&local->mtx);
1185
1186         if (!rcu_access_pointer(local->sched_scan_sdata)) {
1187                 mutex_unlock(&local->mtx);
1188                 return;
1189         }
1190
1191         RCU_INIT_POINTER(local->sched_scan_sdata, NULL);
1192
1193         /* If sched scan was aborted by the driver. */
1194         RCU_INIT_POINTER(local->sched_scan_req, NULL);
1195
1196         mutex_unlock(&local->mtx);
1197
1198         cfg80211_sched_scan_stopped(local->hw.wiphy);
1199 }
1200
1201 void ieee80211_sched_scan_stopped_work(struct work_struct *work)
1202 {
1203         struct ieee80211_local *local =
1204                 container_of(work, struct ieee80211_local,
1205                              sched_scan_stopped_work);
1206
1207         ieee80211_sched_scan_end(local);
1208 }
1209
1210 void ieee80211_sched_scan_stopped(struct ieee80211_hw *hw)
1211 {
1212         struct ieee80211_local *local = hw_to_local(hw);
1213
1214         trace_api_sched_scan_stopped(local);
1215
1216         schedule_work(&local->sched_scan_stopped_work);
1217 }
1218 EXPORT_SYMBOL(ieee80211_sched_scan_stopped);