net/mac80211/scan.c

   1 /*
   2  * Scanning implementation
   3  *
   4  * Copyright 2003, Jouni Malinen <jkmaline@cc.hut.fi>
   5  * Copyright 2004, Instant802 Networks, Inc.
   6  * Copyright 2005, Devicescape Software, Inc.
   7  * Copyright 2006-2007  Jiri Benc <jbenc@suse.cz>
   8  * Copyright 2007, Michael Wu <flamingice@sourmilk.net>
   9  *
  10  * This program is free software; you can redistribute it and/or modify
  11  * it under the terms of the GNU General Public License version 2 as
  12  * published by the Free Software Foundation.
  13  */
  14
  15 #include <linux/if_arp.h>
  16 #include <linux/etherdevice.h>
  17 #include <linux/rtnetlink.h>
  18 #include <linux/pm_qos.h>
  19 #include <net/sch_generic.h>
  20 #include <linux/slab.h>
  21 #include <linux/export.h>
  22 #include <net/mac80211.h>
  23
  24 #include "ieee80211_i.h"
  25 #include "driver-ops.h"
  26 #include "mesh.h"
  27
  28 #define IEEE80211_PROBE_DELAY (HZ / 33)
  29 #define IEEE80211_CHANNEL_TIME (HZ / 33)
  30 #define IEEE80211_PASSIVE_CHANNEL_TIME (HZ / 8)
  31
  32 static void ieee80211_rx_bss_free(struct cfg80211_bss *cbss)
  33 {
  34         struct ieee80211_bss *bss = (void *)cbss->priv;
  35
  36         kfree(bss_mesh_id(bss));
  37         kfree(bss_mesh_cfg(bss));
  38 }
  39
  40 void ieee80211_rx_bss_put(struct ieee80211_local *local,
  41                           struct ieee80211_bss *bss)
  42 {
  43         if (!bss)
  44                 return;
  45         cfg80211_put_bss(container_of((void *)bss, struct cfg80211_bss, priv));
  46 }
  47
  48 static bool is_uapsd_supported(struct ieee802_11_elems *elems)
  49 {
  50         u8 qos_info;
  51
  52         if (elems->wmm_info && elems->wmm_info_len == 7
  53             && elems->wmm_info[5] == 1)
  54                 qos_info = elems->wmm_info[6];
  55         else if (elems->wmm_param && elems->wmm_param_len == 24
  56                  && elems->wmm_param[5] == 1)
  57                 qos_info = elems->wmm_param[6];
  58         else
  59                 /* no valid wmm information or parameter element found */
  60                 return false;
  61
  62         return qos_info & IEEE80211_WMM_IE_AP_QOSINFO_UAPSD;
  63 }
  64
  65 struct ieee80211_bss *
  66 ieee80211_bss_info_update(struct ieee80211_local *local,
  67                           struct ieee80211_rx_status *rx_status,
  68                           struct ieee80211_mgmt *mgmt,
  69                           size_t len,
  70                           struct ieee802_11_elems *elems,
  71                           struct ieee80211_channel *channel,
  72                           bool beacon)
  73 {
  74         struct cfg80211_bss *cbss;
  75         struct ieee80211_bss *bss;
  76         int clen, srlen;
  77         s32 signal = 0;
  78
  79         if (local->hw.flags & IEEE80211_HW_SIGNAL_DBM)
  80                 signal = rx_status->signal * 100;
  81         else if (local->hw.flags & IEEE80211_HW_SIGNAL_UNSPEC)
  82                 signal = (rx_status->signal * 100) / local->hw.max_signal;
  83
  84         cbss = cfg80211_inform_bss_frame(local->hw.wiphy, channel,
  85                                          mgmt, len, signal, GFP_ATOMIC);
  86
  87         if (!cbss)
  88                 return NULL;
  89
  90         cbss->free_priv = ieee80211_rx_bss_free;
  91         bss = (void *)cbss->priv;
  92
  93         if (elems->parse_error) {
  94                 if (beacon)
  95                         bss->corrupt_data |= IEEE80211_BSS_CORRUPT_BEACON;
  96                 else
  97                         bss->corrupt_data |= IEEE80211_BSS_CORRUPT_PROBE_RESP;
  98         } else {
  99                 if (beacon)
 100                         bss->corrupt_data &= ~IEEE80211_BSS_CORRUPT_BEACON;
 101                 else
 102                         bss->corrupt_data &= ~IEEE80211_BSS_CORRUPT_PROBE_RESP;
 103         }
 104
 105         /* save the ERP value so that it is available at association time */
 106         if (elems->erp_info && elems->erp_info_len >= 1 &&
 107                         (!elems->parse_error ||
 108                          !(bss->valid_data & IEEE80211_BSS_VALID_ERP))) {
 109                 bss->erp_value = elems->erp_info[0];
 110                 bss->has_erp_value = true;
 111                 if (!elems->parse_error)
 112                         bss->valid_data |= IEEE80211_BSS_VALID_ERP;
 113         }
 114
 115         if (elems->tim && (!elems->parse_error ||
 116                            !(bss->valid_data & IEEE80211_BSS_VALID_DTIM))) {
 117                 struct ieee80211_tim_ie *tim_ie =
 118                         (struct ieee80211_tim_ie *)elems->tim;
 119                 bss->dtim_period = tim_ie->dtim_period;
 120                 if (!elems->parse_error)
 121                                 bss->valid_data |= IEEE80211_BSS_VALID_DTIM;
 122         }
 123
 124         /* If the beacon had no TIM IE, or it was invalid, use 1 */
 125         if (beacon && !bss->dtim_period)
 126                 bss->dtim_period = 1;
 127
 128         /* replace old supported rates if we get new values */
 129         if (!elems->parse_error ||
 130             !(bss->valid_data & IEEE80211_BSS_VALID_RATES)) {
 131                 srlen = 0;
 132                 if (elems->supp_rates) {
 133                         clen = IEEE80211_MAX_SUPP_RATES;
 134                         if (clen > elems->supp_rates_len)
 135                                 clen = elems->supp_rates_len;
 136                         memcpy(bss->supp_rates, elems->supp_rates, clen);
 137                         srlen += clen;
 138                 }
 139                 if (elems->ext_supp_rates) {
 140                         clen = IEEE80211_MAX_SUPP_RATES - srlen;
 141                         if (clen > elems->ext_supp_rates_len)
 142                                 clen = elems->ext_supp_rates_len;
 143                         memcpy(bss->supp_rates + srlen, elems->ext_supp_rates,
 144                                clen);
 145                         srlen += clen;
 146                 }
 147                 if (srlen) {
 148                         bss->supp_rates_len = srlen;
 149                         if (!elems->parse_error)
 150                                 bss->valid_data |= IEEE80211_BSS_VALID_RATES;
 151                 }
 152         }
 153
 154         if (!elems->parse_error ||
 155             !(bss->valid_data & IEEE80211_BSS_VALID_WMM)) {
 156                 bss->wmm_used = elems->wmm_param || elems->wmm_info;
 157                 bss->uapsd_supported = is_uapsd_supported(elems);
 158                 if (!elems->parse_error)
 159                         bss->valid_data |= IEEE80211_BSS_VALID_WMM;
 160         }
 161
 162         if (!beacon)
 163                 bss->last_probe_resp = jiffies;
 164
 165         return bss;
 166 }
 167
 168 ieee80211_rx_result
 169 ieee80211_scan_rx(struct ieee80211_sub_if_data *sdata, struct sk_buff *skb)
 170 {
 171         struct ieee80211_rx_status *rx_status = IEEE80211_SKB_RXCB(skb);
 172         struct ieee80211_mgmt *mgmt;
 173         struct ieee80211_bss *bss;
 174         u8 *elements;
 175         struct ieee80211_channel *channel;
 176         size_t baselen;
 177         int freq;
 178         __le16 fc;
 179         bool presp, beacon = false;
 180         struct ieee802_11_elems elems;
 181
 182         if (skb->len < 2)
 183                 return RX_DROP_UNUSABLE;
 184
 185         mgmt = (struct ieee80211_mgmt *) skb->data;
 186         fc = mgmt->frame_control;
 187
 188         if (ieee80211_is_ctl(fc))
 189                 return RX_CONTINUE;
 190
 191         if (skb->len < 24)
 192                 return RX_CONTINUE;
 193
 194         presp = ieee80211_is_probe_resp(fc);
 195         if (presp) {
 196                 /* ignore ProbeResp to foreign address */
 197                 if (!ether_addr_equal(mgmt->da, sdata->vif.addr))
 198                         return RX_DROP_MONITOR;
 199
 200                 presp = true;
 201                 elements = mgmt->u.probe_resp.variable;
 202                 baselen = offsetof(struct ieee80211_mgmt, u.probe_resp.variable);
 203         } else {
 204                 beacon = ieee80211_is_beacon(fc);
 205                 baselen = offsetof(struct ieee80211_mgmt, u.beacon.variable);
 206                 elements = mgmt->u.beacon.variable;
 207         }
 208
 209         if (!presp && !beacon)
 210                 return RX_CONTINUE;
 211
 212         if (baselen > skb->len)
 213                 return RX_DROP_MONITOR;
 214
 215         ieee802_11_parse_elems(elements, skb->len - baselen, &elems);
 216
 217         if (elems.ds_params && elems.ds_params_len == 1)
 218                 freq = ieee80211_channel_to_frequency(elems.ds_params[0],
 219                                                       rx_status->band);
 220         else
 221                 freq = rx_status->freq;
 222
 223         channel = ieee80211_get_channel(sdata->local->hw.wiphy, freq);
 224
 225         if (!channel || channel->flags & IEEE80211_CHAN_DISABLED)
 226                 return RX_DROP_MONITOR;
 227
 228         bss = ieee80211_bss_info_update(sdata->local, rx_status,
 229                                         mgmt, skb->len, &elems,
 230                                         channel, beacon);
 231         if (bss)
 232                 ieee80211_rx_bss_put(sdata->local, bss);
 233
 234         if (channel == sdata->local->oper_channel)
 235                 return RX_CONTINUE;
 236
 237         dev_kfree_skb(skb);
 238         return RX_QUEUED;
 239 }
 240
 241 /* return false if no more work */
 242 static bool ieee80211_prep_hw_scan(struct ieee80211_local *local)
 243 {
 244         struct cfg80211_scan_request *req = local->scan_req;
 245         enum ieee80211_band band;
 246         int i, ielen, n_chans;
 247
 248         do {
 249                 if (local->hw_scan_band == IEEE80211_NUM_BANDS)
 250                         return false;
 251
 252                 band = local->hw_scan_band;
 253                 n_chans = 0;
 254                 for (i = 0; i < req->n_channels; i++) {
 255                         if (req->channels[i]->band == band) {
 256                                 local->hw_scan_req->channels[n_chans] =
 257                                                         req->channels[i];
 258                                 n_chans++;
 259                         }
 260                 }
 261
 262                 local->hw_scan_band++;
 263         } while (!n_chans);
 264
 265         local->hw_scan_req->n_channels = n_chans;
 266
 267         ielen = ieee80211_build_preq_ies(local, (u8 *)local->hw_scan_req->ie,
 268                                          req->ie, req->ie_len, band,
 269                                          req->rates[band], 0);
 270         local->hw_scan_req->ie_len = ielen;
 271         local->hw_scan_req->no_cck = req->no_cck;
 272
 273         return true;
 274 }
 275
 276 static void __ieee80211_scan_completed(struct ieee80211_hw *hw, bool aborted,
 277                                        bool was_hw_scan)
 278 {
 279         struct ieee80211_local *local = hw_to_local(hw);
 280
 281         lockdep_assert_held(&local->mtx);
 282
 283         /*
 284          * It's ok to abort a not-yet-running scan (that
 285          * we have one at all will be verified by checking
 286          * local->scan_req next), but not to complete it
 287          * successfully.
 288          */
 289         if (WARN_ON(!local->scanning && !aborted))
 290                 aborted = true;
 291
 292         if (WARN_ON(!local->scan_req))
 293                 return;
 294
 295         if (was_hw_scan && !aborted && ieee80211_prep_hw_scan(local)) {
 296                 int rc;
 297
 298                 rc = drv_hw_scan(local,
 299                         rcu_dereference_protected(local->scan_sdata,
 300                                                   lockdep_is_held(&local->mtx)),
 301                         local->hw_scan_req);
 302
 303                 if (rc == 0)
 304                         return;
 305         }
 306
 307         kfree(local->hw_scan_req);
 308         local->hw_scan_req = NULL;
 309
 310         if (local->scan_req != local->int_scan_req)
 311                 cfg80211_scan_done(local->scan_req, aborted);
 312         local->scan_req = NULL;
 313         local->scan_sdata = NULL;
 314
 315         local->scanning = 0;
 316         local->scan_channel = NULL;
 317
 318         /* Set power back to normal operating levels. */
 319         ieee80211_hw_config(local, 0);
 320
 321         if (!was_hw_scan) {
 322                 ieee80211_configure_filter(local);
 323                 drv_sw_scan_complete(local);
 324                 ieee80211_offchannel_return(local, true);
 325         }
 326
 327         ieee80211_recalc_idle(local);
 328
 329         ieee80211_mlme_notify_scan_completed(local);
 330         ieee80211_ibss_notify_scan_completed(local);
 331         ieee80211_mesh_notify_scan_completed(local);
 332         ieee80211_start_next_roc(local);
 333 }
 334
 335 void ieee80211_scan_completed(struct ieee80211_hw *hw, bool aborted)
 336 {
 337         struct ieee80211_local *local = hw_to_local(hw);
 338
 339         trace_api_scan_completed(local, aborted);
 340
 341         set_bit(SCAN_COMPLETED, &local->scanning);
 342         if (aborted)
 343                 set_bit(SCAN_ABORTED, &local->scanning);
 344         ieee80211_queue_delayed_work(&local->hw, &local->scan_work, 0);
 345 }
 346 EXPORT_SYMBOL(ieee80211_scan_completed);
 347
 348 static int ieee80211_start_sw_scan(struct ieee80211_local *local)
 349 {
 350         /*
 351          * Hardware/driver doesn't support hw_scan, so use software
 352          * scanning instead. First send a nullfunc frame with power save
 353          * bit on so that AP will buffer the frames for us while we are not
 354          * listening, then send probe requests to each channel and wait for
 355          * the responses. After all channels are scanned, tune back to the
 356          * original channel and send a nullfunc frame with power save bit
 357          * off to trigger the AP to send us all the buffered frames.
 358          *
 359          * Note that while local->sw_scanning is true everything else but
 360          * nullfunc frames and probe requests will be dropped in
 361          * ieee80211_tx_h_check_assoc().
 362          */
 363         drv_sw_scan_start(local);
 364
 365         local->leave_oper_channel_time = jiffies;
 366         local->next_scan_state = SCAN_DECISION;
 367         local->scan_channel_idx = 0;
 368
 369         ieee80211_offchannel_stop_vifs(local, true);
 370
 371         ieee80211_configure_filter(local);
 372
 373         /* We need to set power level at maximum rate for scanning. */
 374         ieee80211_hw_config(local, 0);
 375
 376         ieee80211_queue_delayed_work(&local->hw,
 377                                      &local->scan_work, 0);
 378
 379         return 0;
 380 }
 381
 382 static bool ieee80211_can_scan(struct ieee80211_local *local,
 383                                struct ieee80211_sub_if_data *sdata)
 384 {
 385         if (!list_empty(&local->roc_list))
 386                 return false;
 387
 388         if (sdata->vif.type == NL80211_IFTYPE_STATION &&
 389             sdata->u.mgd.flags & (IEEE80211_STA_BEACON_POLL |
 390                                   IEEE80211_STA_CONNECTION_POLL))
 391                 return false;
 392
 393         return true;
 394 }
 395
 396 void ieee80211_run_deferred_scan(struct ieee80211_local *local)
 397 {
 398         lockdep_assert_held(&local->mtx);
 399
 400         if (!local->scan_req || local->scanning)
 401                 return;
 402
 403         if (!ieee80211_can_scan(local,
 404                                 rcu_dereference_protected(
 405                                         local->scan_sdata,
 406                                         lockdep_is_held(&local->mtx))))
 407                 return;
 408
 409         ieee80211_queue_delayed_work(&local->hw, &local->scan_work,
 410                                      round_jiffies_relative(0));
 411 }
 412
 413 static void ieee80211_scan_state_send_probe(struct ieee80211_local *local,
 414                                             unsigned long *next_delay)
 415 {
 416         int i;
 417         struct ieee80211_sub_if_data *sdata;
 418         enum ieee80211_band band = local->hw.conf.channel->band;
 419
 420         sdata = rcu_dereference_protected(local->scan_sdata,
 421                                           lockdep_is_held(&local->mtx));;
 422
 423         for (i = 0; i < local->scan_req->n_ssids; i++)
 424                 ieee80211_send_probe_req(
 425                         sdata, NULL,
 426                         local->scan_req->ssids[i].ssid,
 427                         local->scan_req->ssids[i].ssid_len,
 428                         local->scan_req->ie, local->scan_req->ie_len,
 429                         local->scan_req->rates[band], false,
 430                         local->scan_req->no_cck);
 431
 432         /*
 433          * After sending probe requests, wait for probe responses
 434          * on the channel.
 435          */
 436         *next_delay = IEEE80211_CHANNEL_TIME;
 437         local->next_scan_state = SCAN_DECISION;
 438 }
 439
 440 static int __ieee80211_start_scan(struct ieee80211_sub_if_data *sdata,
 441                                   struct cfg80211_scan_request *req)
 442 {
 443         struct ieee80211_local *local = sdata->local;
 444         int rc;
 445
 446         lockdep_assert_held(&local->mtx);
 447
 448         if (local->scan_req)
 449                 return -EBUSY;
 450
 451         if (!ieee80211_can_scan(local, sdata)) {
 452                 /* wait for the work to finish/time out */
 453                 local->scan_req = req;
 454                 rcu_assign_pointer(local->scan_sdata, sdata);
 455                 return 0;
 456         }
 457
 458         if (local->ops->hw_scan) {
 459                 u8 *ies;
 460
 461                 local->hw_scan_req = kmalloc(
 462                                 sizeof(*local->hw_scan_req) +
 463                                 req->n_channels * sizeof(req->channels[0]) +
 464                                 2 + IEEE80211_MAX_SSID_LEN + local->scan_ies_len +
 465                                 req->ie_len, GFP_KERNEL);
 466                 if (!local->hw_scan_req)
 467                         return -ENOMEM;
 468
 469                 local->hw_scan_req->ssids = req->ssids;
 470                 local->hw_scan_req->n_ssids = req->n_ssids;
 471                 ies = (u8 *)local->hw_scan_req +
 472                         sizeof(*local->hw_scan_req) +
 473                         req->n_channels * sizeof(req->channels[0]);
 474                 local->hw_scan_req->ie = ies;
 475
 476                 local->hw_scan_band = 0;
 477
 478                 /*
 479                  * After allocating local->hw_scan_req, we must
 480                  * go through until ieee80211_prep_hw_scan(), so
 481                  * anything that might be changed here and leave
 482                  * this function early must not go after this
 483                  * allocation.
 484                  */
 485         }
 486
 487         local->scan_req = req;
 488         rcu_assign_pointer(local->scan_sdata, sdata);
 489
 490         if (local->ops->hw_scan) {
 491                 __set_bit(SCAN_HW_SCANNING, &local->scanning);
 492         } else if ((req->n_channels == 1) &&
 493                    (req->channels[0]->center_freq ==
 494                     local->hw.conf.channel->center_freq)) {
 495
 496                 /* If we are scanning only on the current channel, then
 497                  * we do not need to stop normal activities
 498                  */
 499                 unsigned long next_delay;
 500
 501                 __set_bit(SCAN_ONCHANNEL_SCANNING, &local->scanning);
 502
 503                 ieee80211_recalc_idle(local);
 504
 505                 /* Notify driver scan is starting, keep order of operations
 506                  * same as normal software scan, in case that matters. */
 507                 drv_sw_scan_start(local);
 508
 509                 ieee80211_configure_filter(local); /* accept probe-responses */
 510
 511                 /* We need to ensure power level is at max for scanning. */
 512                 ieee80211_hw_config(local, 0);
 513
 514                 if ((req->channels[0]->flags &
 515                      IEEE80211_CHAN_PASSIVE_SCAN) ||
 516                     !local->scan_req->n_ssids) {
 517                         next_delay = IEEE80211_PASSIVE_CHANNEL_TIME;
 518                 } else {
 519                         ieee80211_scan_state_send_probe(local, &next_delay);
 520                         next_delay = IEEE80211_CHANNEL_TIME;
 521                 }
 522
 523                 /* Now, just wait a bit and we are all done! */
 524                 ieee80211_queue_delayed_work(&local->hw, &local->scan_work,
 525                                              next_delay);
 526                 return 0;
 527         } else {
 528                 /* Do normal software scan */
 529                 __set_bit(SCAN_SW_SCANNING, &local->scanning);
 530         }
 531
 532         ieee80211_recalc_idle(local);
 533
 534         if (local->ops->hw_scan) {
 535                 WARN_ON(!ieee80211_prep_hw_scan(local));
 536                 rc = drv_hw_scan(local, sdata, local->hw_scan_req);
 537         } else
 538                 rc = ieee80211_start_sw_scan(local);
 539
 540         if (rc) {
 541                 kfree(local->hw_scan_req);
 542                 local->hw_scan_req = NULL;
 543                 local->scanning = 0;
 544
 545                 ieee80211_recalc_idle(local);
 546
 547                 local->scan_req = NULL;
 548                 rcu_assign_pointer(local->scan_sdata, NULL);
 549         }
 550
 551         return rc;
 552 }
 553
 554 static unsigned long
 555 ieee80211_scan_get_channel_time(struct ieee80211_channel *chan)
 556 {
 557         /*
 558          * TODO: channel switching also consumes quite some time,
 559          * add that delay as well to get a better estimation
 560          */
 561         if (chan->flags & IEEE80211_CHAN_PASSIVE_SCAN)
 562                 return IEEE80211_PASSIVE_CHANNEL_TIME;
 563         return IEEE80211_PROBE_DELAY + IEEE80211_CHANNEL_TIME;
 564 }
 565
 566 static void ieee80211_scan_state_decision(struct ieee80211_local *local,
 567                                           unsigned long *next_delay)
 568 {
 569         bool associated = false;
 570         bool tx_empty = true;
 571         bool bad_latency;
 572         bool listen_int_exceeded;
 573         unsigned long min_beacon_int = 0;
 574         struct ieee80211_sub_if_data *sdata;
 575         struct ieee80211_channel *next_chan;
 576
 577         /*
 578          * check if at least one STA interface is associated,
 579          * check if at least one STA interface has pending tx frames
 580          * and grab the lowest used beacon interval
 581          */
 582         mutex_lock(&local->iflist_mtx);
 583         list_for_each_entry(sdata, &local->interfaces, list) {
 584                 if (!ieee80211_sdata_running(sdata))
 585                         continue;
 586
 587                 if (sdata->vif.type == NL80211_IFTYPE_STATION) {
 588                         if (sdata->u.mgd.associated) {
 589                                 associated = true;
 590
 591                                 if (sdata->vif.bss_conf.beacon_int <
 592                                     min_beacon_int || min_beacon_int == 0)
 593                                         min_beacon_int =
 594                                                 sdata->vif.bss_conf.beacon_int;
 595
 596                                 if (!qdisc_all_tx_empty(sdata->dev)) {
 597                                         tx_empty = false;
 598                                         break;
 599                                 }
 600                         }
 601                 }
 602         }
 603         mutex_unlock(&local->iflist_mtx);
 604
 605         next_chan = local->scan_req->channels[local->scan_channel_idx];
 606
 607         /*
 608          * we're currently scanning a different channel, let's
 609          * see if we can scan another channel without interfering
 610          * with the current traffic situation.
 611          *
 612          * Since we don't know if the AP has pending frames for us
 613          * we can only check for our tx queues and use the current
 614          * pm_qos requirements for rx. Hence, if no tx traffic occurs
 615          * at all we will scan as many channels in a row as the pm_qos
 616          * latency allows us to. Additionally we also check for the
 617          * currently negotiated listen interval to prevent losing
 618          * frames unnecessarily.
 619          *
 620          * Otherwise switch back to the operating channel.
 621          */
 622
 623         bad_latency = time_after(jiffies +
 624                         ieee80211_scan_get_channel_time(next_chan),
 625                         local->leave_oper_channel_time +
 626                         usecs_to_jiffies(pm_qos_request(PM_QOS_NETWORK_LATENCY)));
 627
 628         listen_int_exceeded = time_after(jiffies +
 629                         ieee80211_scan_get_channel_time(next_chan),
 630                         local->leave_oper_channel_time +
 631                         usecs_to_jiffies(min_beacon_int * 1024) *
 632                         local->hw.conf.listen_interval);
 633
 634         if (associated && (!tx_empty || bad_latency || listen_int_exceeded))
 635                 local->next_scan_state = SCAN_SUSPEND;
 636         else
 637                 local->next_scan_state = SCAN_SET_CHANNEL;
 638
 639         *next_delay = 0;
 640 }
 641
 642 static void ieee80211_scan_state_set_channel(struct ieee80211_local *local,
 643                                              unsigned long *next_delay)
 644 {
 645         int skip;
 646         struct ieee80211_channel *chan;
 647
 648         skip = 0;
 649         chan = local->scan_req->channels[local->scan_channel_idx];
 650
 651         local->scan_channel = chan;
 652
 653         if (ieee80211_hw_config(local, IEEE80211_CONF_CHANGE_CHANNEL))
 654                 skip = 1;
 655
 656         /* advance state machine to next channel/band */
 657         local->scan_channel_idx++;
 658
 659         if (skip) {
 660                 /* if we skip this channel return to the decision state */
 661                 local->next_scan_state = SCAN_DECISION;
 662                 return;
 663         }
 664
 665         /*
 666          * Probe delay is used to update the NAV, cf. 11.1.3.2.2
 667          * (which unfortunately doesn't say _why_ step a) is done,
 668          * but it waits for the probe delay or until a frame is
 669          * received - and the received frame would update the NAV).
 670          * For now, we do not support waiting until a frame is
 671          * received.
 672          *
 673          * In any case, it is not necessary for a passive scan.
 674          */
 675         if (chan->flags & IEEE80211_CHAN_PASSIVE_SCAN ||
 676             !local->scan_req->n_ssids) {
 677                 *next_delay = IEEE80211_PASSIVE_CHANNEL_TIME;
 678                 local->next_scan_state = SCAN_DECISION;
 679                 return;
 680         }
 681
 682         /* active scan, send probes */
 683         *next_delay = IEEE80211_PROBE_DELAY;
 684         local->next_scan_state = SCAN_SEND_PROBE;
 685 }
 686
 687 static void ieee80211_scan_state_suspend(struct ieee80211_local *local,
 688                                          unsigned long *next_delay)
 689 {
 690         /* switch back to the operating channel */
 691         local->scan_channel = NULL;
 692         ieee80211_hw_config(local, IEEE80211_CONF_CHANGE_CHANNEL);
 693
 694         /*
 695          * Re-enable vifs and beaconing.  Leave PS
 696          * in off-channel state..will put that back
 697          * on-channel at the end of scanning.
 698          */
 699         ieee80211_offchannel_return(local, false);
 700
 701         *next_delay = HZ / 5;
 702         /* afterwards, resume scan & go to next channel */
 703         local->next_scan_state = SCAN_RESUME;
 704 }
 705
 706 static void ieee80211_scan_state_resume(struct ieee80211_local *local,
 707                                         unsigned long *next_delay)
 708 {
 709         /* PS already is in off-channel mode */
 710         ieee80211_offchannel_stop_vifs(local, false);
 711
 712         if (local->ops->flush) {
 713                 drv_flush(local, false);
 714                 *next_delay = 0;
 715         } else
 716                 *next_delay = HZ / 10;
 717
 718         /* remember when we left the operating channel */
 719         local->leave_oper_channel_time = jiffies;
 720
 721         /* advance to the next channel to be scanned */
 722         local->next_scan_state = SCAN_SET_CHANNEL;
 723 }
 724
 725 void ieee80211_scan_work(struct work_struct *work)
 726 {
 727         struct ieee80211_local *local =
 728                 container_of(work, struct ieee80211_local, scan_work.work);
 729         struct ieee80211_sub_if_data *sdata;
 730         unsigned long next_delay = 0;
 731         bool aborted, hw_scan;
 732
 733         mutex_lock(&local->mtx);
 734
 735         sdata = rcu_dereference_protected(local->scan_sdata,
 736                                           lockdep_is_held(&local->mtx));
 737
 738         /* When scanning on-channel, the first-callback means completed. */
 739         if (test_bit(SCAN_ONCHANNEL_SCANNING, &local->scanning)) {
 740                 aborted = test_and_clear_bit(SCAN_ABORTED, &local->scanning);
 741                 goto out_complete;
 742         }
 743
 744         if (test_and_clear_bit(SCAN_COMPLETED, &local->scanning)) {
 745                 aborted = test_and_clear_bit(SCAN_ABORTED, &local->scanning);
 746                 goto out_complete;
 747         }
 748
 749         if (!sdata || !local->scan_req)
 750                 goto out;
 751
 752         if (local->scan_req && !local->scanning) {
 753                 struct cfg80211_scan_request *req = local->scan_req;
 754                 int rc;
 755
 756                 local->scan_req = NULL;
 757                 rcu_assign_pointer(local->scan_sdata, NULL);
 758
 759                 rc = __ieee80211_start_scan(sdata, req);
 760                 if (rc) {
 761                         /* need to complete scan in cfg80211 */
 762                         local->scan_req = req;
 763                         aborted = true;
 764                         goto out_complete;
 765                 } else
 766                         goto out;
 767         }
 768
 769         /*
 770          * Avoid re-scheduling when the sdata is going away.
 771          */
 772         if (!ieee80211_sdata_running(sdata)) {
 773                 aborted = true;
 774                 goto out_complete;
 775         }
 776
 777         /*
 778          * as long as no delay is required advance immediately
 779          * without scheduling a new work
 780          */
 781         do {
 782                 if (!ieee80211_sdata_running(sdata)) {
 783                         aborted = true;
 784                         goto out_complete;
 785                 }
 786
 787                 switch (local->next_scan_state) {
 788                 case SCAN_DECISION:
 789                         /* if no more bands/channels left, complete scan */
 790                         if (local->scan_channel_idx >= local->scan_req->n_channels) {
 791                                 aborted = false;
 792                                 goto out_complete;
 793                         }
 794                         ieee80211_scan_state_decision(local, &next_delay);
 795                         break;
 796                 case SCAN_SET_CHANNEL:
 797                         ieee80211_scan_state_set_channel(local, &next_delay);
 798                         break;
 799                 case SCAN_SEND_PROBE:
 800                         ieee80211_scan_state_send_probe(local, &next_delay);
 801                         break;
 802                 case SCAN_SUSPEND:
 803                         ieee80211_scan_state_suspend(local, &next_delay);
 804                         break;
 805                 case SCAN_RESUME:
 806                         ieee80211_scan_state_resume(local, &next_delay);
 807                         break;
 808                 }
 809         } while (next_delay == 0);
 810
 811         ieee80211_queue_delayed_work(&local->hw, &local->scan_work, next_delay);
 812         goto out;
 813
 814 out_complete:
 815         hw_scan = test_bit(SCAN_HW_SCANNING, &local->scanning);
 816         __ieee80211_scan_completed(&local->hw, aborted, hw_scan);
 817 out:
 818         mutex_unlock(&local->mtx);
 819 }
 820
 821 int ieee80211_request_scan(struct ieee80211_sub_if_data *sdata,
 822                            struct cfg80211_scan_request *req)
 823 {
 824         int res;
 825
 826         mutex_lock(&sdata->local->mtx);
 827         res = __ieee80211_start_scan(sdata, req);
 828         mutex_unlock(&sdata->local->mtx);
 829
 830         return res;
 831 }
 832
 833 int ieee80211_request_internal_scan(struct ieee80211_sub_if_data *sdata,
 834                                     const u8 *ssid, u8 ssid_len,
 835                                     struct ieee80211_channel *chan)
 836 {
 837         struct ieee80211_local *local = sdata->local;
 838         int ret = -EBUSY;
 839         enum ieee80211_band band;
 840
 841         mutex_lock(&local->mtx);
 842
 843         /* busy scanning */
 844         if (local->scan_req)
 845                 goto unlock;
 846
 847         /* fill internal scan request */
 848         if (!chan) {
 849                 int i, nchan = 0;
 850
 851                 for (band = 0; band < IEEE80211_NUM_BANDS; band++) {
 852                         if (!local->hw.wiphy->bands[band])
 853                                 continue;
 854                         for (i = 0;
 855                              i < local->hw.wiphy->bands[band]->n_channels;
 856                              i++) {
 857                                 local->int_scan_req->channels[nchan] =
 858                                     &local->hw.wiphy->bands[band]->channels[i];
 859                                 nchan++;
 860                         }
 861                 }
 862
 863                 local->int_scan_req->n_channels = nchan;
 864         } else {
 865                 local->int_scan_req->channels[0] = chan;
 866                 local->int_scan_req->n_channels = 1;
 867         }
 868
 869         local->int_scan_req->ssids = &local->scan_ssid;
 870         local->int_scan_req->n_ssids = 1;
 871         memcpy(local->int_scan_req->ssids[0].ssid, ssid, IEEE80211_MAX_SSID_LEN);
 872         local->int_scan_req->ssids[0].ssid_len = ssid_len;
 873
 874         ret = __ieee80211_start_scan(sdata, sdata->local->int_scan_req);
 875  unlock:
 876         mutex_unlock(&local->mtx);
 877         return ret;
 878 }
 879
 880 /*
 881  * Only call this function when a scan can't be queued -- under RTNL.
 882  */
 883 void ieee80211_scan_cancel(struct ieee80211_local *local)
 884 {
 885         /*
 886          * We are canceling software scan, or deferred scan that was not
 887          * yet really started (see __ieee80211_start_scan ).
 888          *
 889          * Regarding hardware scan:
 890          * - we can not call  __ieee80211_scan_completed() as when
 891          *   SCAN_HW_SCANNING bit is set this function change
 892          *   local->hw_scan_req to operate on 5G band, what race with
 893          *   driver which can use local->hw_scan_req
 894          *
 895          * - we can not cancel scan_work since driver can schedule it
 896          *   by ieee80211_scan_completed(..., true) to finish scan
 897          *
 898          * Hence we only call the cancel_hw_scan() callback, but the low-level
 899          * driver is still responsible for calling ieee80211_scan_completed()
 900          * after the scan was completed/aborted.
 901          */
 902
 903         mutex_lock(&local->mtx);
 904         if (!local->scan_req)
 905                 goto out;
 906
 907         if (test_bit(SCAN_HW_SCANNING, &local->scanning)) {
 908                 if (local->ops->cancel_hw_scan)
 909                         drv_cancel_hw_scan(local,
 910                                 rcu_dereference_protected(local->scan_sdata,
 911                                                 lockdep_is_held(&local->mtx)));
 912                 goto out;
 913         }
 914
 915         /*
 916          * If the work is currently running, it must be blocked on
 917          * the mutex, but we'll set scan_sdata = NULL and it'll
 918          * simply exit once it acquires the mutex.
 919          */
 920         cancel_delayed_work(&local->scan_work);
 921         /* and clean up */
 922         __ieee80211_scan_completed(&local->hw, true, false);
 923 out:
 924         mutex_unlock(&local->mtx);
 925 }
 926
 927 int ieee80211_request_sched_scan_start(struct ieee80211_sub_if_data *sdata,
 928                                        struct cfg80211_sched_scan_request *req)
 929 {
 930         struct ieee80211_local *local = sdata->local;
 931         int ret, i;
 932
 933         mutex_lock(&local->mtx);
 934
 935         if (rcu_access_pointer(local->sched_scan_sdata)) {
 936                 ret = -EBUSY;
 937                 goto out;
 938         }
 939
 940         if (!local->ops->sched_scan_start) {
 941                 ret = -ENOTSUPP;
 942                 goto out;
 943         }
 944
 945         for (i = 0; i < IEEE80211_NUM_BANDS; i++) {
 946                 if (!local->hw.wiphy->bands[i])
 947                         continue;
 948
 949                 local->sched_scan_ies.ie[i] = kzalloc(2 +
 950                                                       IEEE80211_MAX_SSID_LEN +
 951                                                       local->scan_ies_len +
 952                                                       req->ie_len,
 953                                                       GFP_KERNEL);
 954                 if (!local->sched_scan_ies.ie[i]) {
 955                         ret = -ENOMEM;
 956                         goto out_free;
 957                 }
 958
 959                 local->sched_scan_ies.len[i] =
 960                         ieee80211_build_preq_ies(local,
 961                                                  local->sched_scan_ies.ie[i],
 962                                                  req->ie, req->ie_len, i,
 963                                                  (u32) -1, 0);
 964         }
 965
 966         ret = drv_sched_scan_start(local, sdata, req,
 967                                    &local->sched_scan_ies);
 968         if (ret == 0) {
 969                 rcu_assign_pointer(local->sched_scan_sdata, sdata);
 970                 goto out;
 971         }
 972
 973 out_free:
 974         while (i > 0)
 975                 kfree(local->sched_scan_ies.ie[--i]);
 976 out:
 977         mutex_unlock(&local->mtx);
 978         return ret;
 979 }
 980
 981 int ieee80211_request_sched_scan_stop(struct ieee80211_sub_if_data *sdata)
 982 {
 983         struct ieee80211_local *local = sdata->local;
 984         int ret = 0, i;
 985
 986         mutex_lock(&local->mtx);
 987
 988         if (!local->ops->sched_scan_stop) {
 989                 ret = -ENOTSUPP;
 990                 goto out;
 991         }
 992
 993         if (rcu_access_pointer(local->sched_scan_sdata)) {
 994                 for (i = 0; i < IEEE80211_NUM_BANDS; i++)
 995                         kfree(local->sched_scan_ies.ie[i]);
 996
 997                 drv_sched_scan_stop(local, sdata);
 998                 rcu_assign_pointer(local->sched_scan_sdata, NULL);
 999         }
1000 out:
1001         mutex_unlock(&local->mtx);
1002
1003         return ret;
1004 }
1005
1006 void ieee80211_sched_scan_results(struct ieee80211_hw *hw)
1007 {
1008         struct ieee80211_local *local = hw_to_local(hw);
1009
1010         trace_api_sched_scan_results(local);
1011
1012         cfg80211_sched_scan_results(hw->wiphy);
1013 }
1014 EXPORT_SYMBOL(ieee80211_sched_scan_results);
1015
1016 void ieee80211_sched_scan_stopped_work(struct work_struct *work)
1017 {
1018         struct ieee80211_local *local =
1019                 container_of(work, struct ieee80211_local,
1020                              sched_scan_stopped_work);
1021         int i;
1022
1023         mutex_lock(&local->mtx);
1024
1025         if (!rcu_access_pointer(local->sched_scan_sdata)) {
1026                 mutex_unlock(&local->mtx);
1027                 return;
1028         }
1029
1030         for (i = 0; i < IEEE80211_NUM_BANDS; i++)
1031                 kfree(local->sched_scan_ies.ie[i]);
1032
1033         rcu_assign_pointer(local->sched_scan_sdata, NULL);
1034
1035         mutex_unlock(&local->mtx);
1036
1037         cfg80211_sched_scan_stopped(local->hw.wiphy);
1038 }
1039
1040 void ieee80211_sched_scan_stopped(struct ieee80211_hw *hw)
1041 {
1042         struct ieee80211_local *local = hw_to_local(hw);
1043
1044         trace_api_sched_scan_stopped(local);
1045
1046         ieee80211_queue_work(&local->hw, &local->sched_scan_stopped_work);
1047 }
1048 EXPORT_SYMBOL(ieee80211_sched_scan_stopped);