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         if (!cbss)
  87                 return NULL;
  88
  89         cbss->free_priv = ieee80211_rx_bss_free;
  90         bss = (void *)cbss->priv;
  91
  92         bss->device_ts = rx_status->device_timestamp;
  93
  94         if (elems->parse_error) {
  95                 if (beacon)
  96                         bss->corrupt_data |= IEEE80211_BSS_CORRUPT_BEACON;
  97                 else
  98                         bss->corrupt_data |= IEEE80211_BSS_CORRUPT_PROBE_RESP;
  99         } else {
 100                 if (beacon)
 101                         bss->corrupt_data &= ~IEEE80211_BSS_CORRUPT_BEACON;
 102                 else
 103                         bss->corrupt_data &= ~IEEE80211_BSS_CORRUPT_PROBE_RESP;
 104         }
 105
 106         /* save the ERP value so that it is available at association time */
 107         if (elems->erp_info && elems->erp_info_len >= 1 &&
 108                         (!elems->parse_error ||
 109                          !(bss->valid_data & IEEE80211_BSS_VALID_ERP))) {
 110                 bss->erp_value = elems->erp_info[0];
 111                 bss->has_erp_value = true;
 112                 if (!elems->parse_error)
 113                         bss->valid_data |= IEEE80211_BSS_VALID_ERP;
 114         }
 115
 116         /* replace old supported rates if we get new values */
 117         if (!elems->parse_error ||
 118             !(bss->valid_data & IEEE80211_BSS_VALID_RATES)) {
 119                 srlen = 0;
 120                 if (elems->supp_rates) {
 121                         clen = IEEE80211_MAX_SUPP_RATES;
 122                         if (clen > elems->supp_rates_len)
 123                                 clen = elems->supp_rates_len;
 124                         memcpy(bss->supp_rates, elems->supp_rates, clen);
 125                         srlen += clen;
 126                 }
 127                 if (elems->ext_supp_rates) {
 128                         clen = IEEE80211_MAX_SUPP_RATES - srlen;
 129                         if (clen > elems->ext_supp_rates_len)
 130                                 clen = elems->ext_supp_rates_len;
 131                         memcpy(bss->supp_rates + srlen, elems->ext_supp_rates,
 132                                clen);
 133                         srlen += clen;
 134                 }
 135                 if (srlen) {
 136                         bss->supp_rates_len = srlen;
 137                         if (!elems->parse_error)
 138                                 bss->valid_data |= IEEE80211_BSS_VALID_RATES;
 139                 }
 140         }
 141
 142         if (!elems->parse_error ||
 143             !(bss->valid_data & IEEE80211_BSS_VALID_WMM)) {
 144                 bss->wmm_used = elems->wmm_param || elems->wmm_info;
 145                 bss->uapsd_supported = is_uapsd_supported(elems);
 146                 if (!elems->parse_error)
 147                         bss->valid_data |= IEEE80211_BSS_VALID_WMM;
 148         }
 149
 150         if (!beacon)
 151                 bss->last_probe_resp = jiffies;
 152
 153         return bss;
 154 }
 155
 156 void ieee80211_scan_rx(struct ieee80211_local *local, struct sk_buff *skb)
 157 {
 158         struct ieee80211_rx_status *rx_status = IEEE80211_SKB_RXCB(skb);
 159         struct ieee80211_sub_if_data *sdata1, *sdata2;
 160         struct ieee80211_mgmt *mgmt = (void *)skb->data;
 161         struct ieee80211_bss *bss;
 162         u8 *elements;
 163         struct ieee80211_channel *channel;
 164         size_t baselen;
 165         bool beacon;
 166         struct ieee802_11_elems elems;
 167
 168         if (skb->len < 24 ||
 169             (!ieee80211_is_probe_resp(mgmt->frame_control) &&
 170              !ieee80211_is_beacon(mgmt->frame_control)))
 171                 return;
 172
 173         sdata1 = rcu_dereference(local->scan_sdata);
 174         sdata2 = rcu_dereference(local->sched_scan_sdata);
 175
 176         if (likely(!sdata1 && !sdata2))
 177                 return;
 178
 179         if (ieee80211_is_probe_resp(mgmt->frame_control)) {
 180                 /* ignore ProbeResp to foreign address */
 181                 if ((!sdata1 || !ether_addr_equal(mgmt->da, sdata1->vif.addr)) &&
 182                     (!sdata2 || !ether_addr_equal(mgmt->da, sdata2->vif.addr)))
 183                         return;
 184
 185                 elements = mgmt->u.probe_resp.variable;
 186                 baselen = offsetof(struct ieee80211_mgmt, u.probe_resp.variable);
 187                 beacon = false;
 188         } else {
 189                 baselen = offsetof(struct ieee80211_mgmt, u.beacon.variable);
 190                 elements = mgmt->u.beacon.variable;
 191                 beacon = true;
 192         }
 193
 194         if (baselen > skb->len)
 195                 return;
 196
 197         ieee802_11_parse_elems(elements, skb->len - baselen, &elems);
 198
 199         channel = ieee80211_get_channel(local->hw.wiphy, rx_status->freq);
 200
 201         if (!channel || channel->flags & IEEE80211_CHAN_DISABLED)
 202                 return;
 203
 204         bss = ieee80211_bss_info_update(local, rx_status,
 205                                         mgmt, skb->len, &elems,
 206                                         channel, beacon);
 207         if (bss)
 208                 ieee80211_rx_bss_put(local, bss);
 209 }
 210
 211 /* return false if no more work */
 212 static bool ieee80211_prep_hw_scan(struct ieee80211_local *local)
 213 {
 214         struct cfg80211_scan_request *req = local->scan_req;
 215         enum ieee80211_band band;
 216         int i, ielen, n_chans;
 217
 218         do {
 219                 if (local->hw_scan_band == IEEE80211_NUM_BANDS)
 220                         return false;
 221
 222                 band = local->hw_scan_band;
 223                 n_chans = 0;
 224                 for (i = 0; i < req->n_channels; i++) {
 225                         if (req->channels[i]->band == band) {
 226                                 local->hw_scan_req->channels[n_chans] =
 227                                                         req->channels[i];
 228                                 n_chans++;
 229                         }
 230                 }
 231
 232                 local->hw_scan_band++;
 233         } while (!n_chans);
 234
 235         local->hw_scan_req->n_channels = n_chans;
 236
 237         ielen = ieee80211_build_preq_ies(local, (u8 *)local->hw_scan_req->ie,
 238                                          local->hw_scan_ies_bufsize,
 239                                          req->ie, req->ie_len, band,
 240                                          req->rates[band], 0);
 241         local->hw_scan_req->ie_len = ielen;
 242         local->hw_scan_req->no_cck = req->no_cck;
 243
 244         return true;
 245 }
 246
 247 static void __ieee80211_scan_completed(struct ieee80211_hw *hw, bool aborted,
 248                                        bool was_hw_scan)
 249 {
 250         struct ieee80211_local *local = hw_to_local(hw);
 251
 252         lockdep_assert_held(&local->mtx);
 253
 254         /*
 255          * It's ok to abort a not-yet-running scan (that
 256          * we have one at all will be verified by checking
 257          * local->scan_req next), but not to complete it
 258          * successfully.
 259          */
 260         if (WARN_ON(!local->scanning && !aborted))
 261                 aborted = true;
 262
 263         if (WARN_ON(!local->scan_req))
 264                 return;
 265
 266         if (was_hw_scan && !aborted && ieee80211_prep_hw_scan(local)) {
 267                 int rc;
 268
 269                 rc = drv_hw_scan(local,
 270                         rcu_dereference_protected(local->scan_sdata,
 271                                                   lockdep_is_held(&local->mtx)),
 272                         local->hw_scan_req);
 273
 274                 if (rc == 0)
 275                         return;
 276         }
 277
 278         kfree(local->hw_scan_req);
 279         local->hw_scan_req = NULL;
 280
 281         if (local->scan_req != local->int_scan_req)
 282                 cfg80211_scan_done(local->scan_req, aborted);
 283         local->scan_req = NULL;
 284         rcu_assign_pointer(local->scan_sdata, NULL);
 285
 286         local->scanning = 0;
 287         local->scan_channel = NULL;
 288
 289         /* Set power back to normal operating levels. */
 290         ieee80211_hw_config(local, 0);
 291
 292         if (!was_hw_scan) {
 293                 ieee80211_configure_filter(local);
 294                 drv_sw_scan_complete(local);
 295                 ieee80211_offchannel_return(local);
 296         }
 297
 298         ieee80211_recalc_idle(local);
 299
 300         ieee80211_mlme_notify_scan_completed(local);
 301         ieee80211_ibss_notify_scan_completed(local);
 302         ieee80211_mesh_notify_scan_completed(local);
 303         ieee80211_start_next_roc(local);
 304 }
 305
 306 void ieee80211_scan_completed(struct ieee80211_hw *hw, bool aborted)
 307 {
 308         struct ieee80211_local *local = hw_to_local(hw);
 309
 310         trace_api_scan_completed(local, aborted);
 311
 312         set_bit(SCAN_COMPLETED, &local->scanning);
 313         if (aborted)
 314                 set_bit(SCAN_ABORTED, &local->scanning);
 315         ieee80211_queue_delayed_work(&local->hw, &local->scan_work, 0);
 316 }
 317 EXPORT_SYMBOL(ieee80211_scan_completed);
 318
 319 static int ieee80211_start_sw_scan(struct ieee80211_local *local)
 320 {
 321         /* Software scan is not supported in multi-channel cases */
 322         if (local->use_chanctx)
 323                 return -EOPNOTSUPP;
 324
 325         /*
 326          * Hardware/driver doesn't support hw_scan, so use software
 327          * scanning instead. First send a nullfunc frame with power save
 328          * bit on so that AP will buffer the frames for us while we are not
 329          * listening, then send probe requests to each channel and wait for
 330          * the responses. After all channels are scanned, tune back to the
 331          * original channel and send a nullfunc frame with power save bit
 332          * off to trigger the AP to send us all the buffered frames.
 333          *
 334          * Note that while local->sw_scanning is true everything else but
 335          * nullfunc frames and probe requests will be dropped in
 336          * ieee80211_tx_h_check_assoc().
 337          */
 338         drv_sw_scan_start(local);
 339
 340         local->leave_oper_channel_time = jiffies;
 341         local->next_scan_state = SCAN_DECISION;
 342         local->scan_channel_idx = 0;
 343
 344         ieee80211_offchannel_stop_vifs(local);
 345
 346         ieee80211_configure_filter(local);
 347
 348         /* We need to set power level at maximum rate for scanning. */
 349         ieee80211_hw_config(local, 0);
 350
 351         ieee80211_queue_delayed_work(&local->hw,
 352                                      &local->scan_work, 0);
 353
 354         return 0;
 355 }
 356
 357 static bool ieee80211_can_scan(struct ieee80211_local *local,
 358                                struct ieee80211_sub_if_data *sdata)
 359 {
 360         if (!list_empty(&local->roc_list))
 361                 return false;
 362
 363         if (sdata->vif.type == NL80211_IFTYPE_STATION &&
 364             sdata->u.mgd.flags & (IEEE80211_STA_BEACON_POLL |
 365                                   IEEE80211_STA_CONNECTION_POLL))
 366                 return false;
 367
 368         return true;
 369 }
 370
 371 void ieee80211_run_deferred_scan(struct ieee80211_local *local)
 372 {
 373         lockdep_assert_held(&local->mtx);
 374
 375         if (!local->scan_req || local->scanning)
 376                 return;
 377
 378         if (!ieee80211_can_scan(local,
 379                                 rcu_dereference_protected(
 380                                         local->scan_sdata,
 381                                         lockdep_is_held(&local->mtx))))
 382                 return;
 383
 384         ieee80211_queue_delayed_work(&local->hw, &local->scan_work,
 385                                      round_jiffies_relative(0));
 386 }
 387
 388 static void ieee80211_scan_state_send_probe(struct ieee80211_local *local,
 389                                             unsigned long *next_delay)
 390 {
 391         int i;
 392         struct ieee80211_sub_if_data *sdata;
 393         enum ieee80211_band band = local->hw.conf.channel->band;
 394
 395         sdata = rcu_dereference_protected(local->scan_sdata,
 396                                           lockdep_is_held(&local->mtx));
 397
 398         for (i = 0; i < local->scan_req->n_ssids; i++)
 399                 ieee80211_send_probe_req(
 400                         sdata, NULL,
 401                         local->scan_req->ssids[i].ssid,
 402                         local->scan_req->ssids[i].ssid_len,
 403                         local->scan_req->ie, local->scan_req->ie_len,
 404                         local->scan_req->rates[band], false,
 405                         local->scan_req->no_cck,
 406                         local->hw.conf.channel, true);
 407
 408         /*
 409          * After sending probe requests, wait for probe responses
 410          * on the channel.
 411          */
 412         *next_delay = IEEE80211_CHANNEL_TIME;
 413         local->next_scan_state = SCAN_DECISION;
 414 }
 415
 416 static int __ieee80211_start_scan(struct ieee80211_sub_if_data *sdata,
 417                                   struct cfg80211_scan_request *req)
 418 {
 419         struct ieee80211_local *local = sdata->local;
 420         int rc;
 421
 422         lockdep_assert_held(&local->mtx);
 423
 424         if (local->scan_req)
 425                 return -EBUSY;
 426
 427         if (!ieee80211_can_scan(local, sdata)) {
 428                 /* wait for the work to finish/time out */
 429                 local->scan_req = req;
 430                 rcu_assign_pointer(local->scan_sdata, sdata);
 431                 return 0;
 432         }
 433
 434         if (local->ops->hw_scan) {
 435                 u8 *ies;
 436
 437                 local->hw_scan_ies_bufsize = 2 + IEEE80211_MAX_SSID_LEN +
 438                                              local->scan_ies_len +
 439                                              req->ie_len;
 440                 local->hw_scan_req = kmalloc(
 441                                 sizeof(*local->hw_scan_req) +
 442                                 req->n_channels * sizeof(req->channels[0]) +
 443                                 local->hw_scan_ies_bufsize, GFP_KERNEL);
 444                 if (!local->hw_scan_req)
 445                         return -ENOMEM;
 446
 447                 local->hw_scan_req->ssids = req->ssids;
 448                 local->hw_scan_req->n_ssids = req->n_ssids;
 449                 ies = (u8 *)local->hw_scan_req +
 450                         sizeof(*local->hw_scan_req) +
 451                         req->n_channels * sizeof(req->channels[0]);
 452                 local->hw_scan_req->ie = ies;
 453                 local->hw_scan_req->flags = req->flags;
 454
 455                 local->hw_scan_band = 0;
 456
 457                 /*
 458                  * After allocating local->hw_scan_req, we must
 459                  * go through until ieee80211_prep_hw_scan(), so
 460                  * anything that might be changed here and leave
 461                  * this function early must not go after this
 462                  * allocation.
 463                  */
 464         }
 465
 466         local->scan_req = req;
 467         rcu_assign_pointer(local->scan_sdata, sdata);
 468
 469         if (local->ops->hw_scan) {
 470                 __set_bit(SCAN_HW_SCANNING, &local->scanning);
 471         } else if ((req->n_channels == 1) &&
 472                    (req->channels[0] == local->_oper_channel)) {
 473                 /*
 474                  * If we are scanning only on the operating channel
 475                  * then we do not need to stop normal activities
 476                  */
 477                 unsigned long next_delay;
 478
 479                 __set_bit(SCAN_ONCHANNEL_SCANNING, &local->scanning);
 480
 481                 ieee80211_recalc_idle(local);
 482
 483                 /* Notify driver scan is starting, keep order of operations
 484                  * same as normal software scan, in case that matters. */
 485                 drv_sw_scan_start(local);
 486
 487                 ieee80211_configure_filter(local); /* accept probe-responses */
 488
 489                 /* We need to ensure power level is at max for scanning. */
 490                 ieee80211_hw_config(local, 0);
 491
 492                 if ((req->channels[0]->flags &
 493                      IEEE80211_CHAN_PASSIVE_SCAN) ||
 494                     !local->scan_req->n_ssids) {
 495                         next_delay = IEEE80211_PASSIVE_CHANNEL_TIME;
 496                 } else {
 497                         ieee80211_scan_state_send_probe(local, &next_delay);
 498                         next_delay = IEEE80211_CHANNEL_TIME;
 499                 }
 500
 501                 /* Now, just wait a bit and we are all done! */
 502                 ieee80211_queue_delayed_work(&local->hw, &local->scan_work,
 503                                              next_delay);
 504                 return 0;
 505         } else {
 506                 /* Do normal software scan */
 507                 __set_bit(SCAN_SW_SCANNING, &local->scanning);
 508         }
 509
 510         ieee80211_recalc_idle(local);
 511
 512         if (local->ops->hw_scan) {
 513                 WARN_ON(!ieee80211_prep_hw_scan(local));
 514                 rc = drv_hw_scan(local, sdata, local->hw_scan_req);
 515         } else
 516                 rc = ieee80211_start_sw_scan(local);
 517
 518         if (rc) {
 519                 kfree(local->hw_scan_req);
 520                 local->hw_scan_req = NULL;
 521                 local->scanning = 0;
 522
 523                 ieee80211_recalc_idle(local);
 524
 525                 local->scan_req = NULL;
 526                 rcu_assign_pointer(local->scan_sdata, NULL);
 527         }
 528
 529         return rc;
 530 }
 531
 532 static unsigned long
 533 ieee80211_scan_get_channel_time(struct ieee80211_channel *chan)
 534 {
 535         /*
 536          * TODO: channel switching also consumes quite some time,
 537          * add that delay as well to get a better estimation
 538          */
 539         if (chan->flags & IEEE80211_CHAN_PASSIVE_SCAN)
 540                 return IEEE80211_PASSIVE_CHANNEL_TIME;
 541         return IEEE80211_PROBE_DELAY + IEEE80211_CHANNEL_TIME;
 542 }
 543
 544 static void ieee80211_scan_state_decision(struct ieee80211_local *local,
 545                                           unsigned long *next_delay)
 546 {
 547         bool associated = false;
 548         bool tx_empty = true;
 549         bool bad_latency;
 550         bool listen_int_exceeded;
 551         unsigned long min_beacon_int = 0;
 552         struct ieee80211_sub_if_data *sdata;
 553         struct ieee80211_channel *next_chan;
 554         enum mac80211_scan_state next_scan_state;
 555
 556         /*
 557          * check if at least one STA interface is associated,
 558          * check if at least one STA interface has pending tx frames
 559          * and grab the lowest used beacon interval
 560          */
 561         mutex_lock(&local->iflist_mtx);
 562         list_for_each_entry(sdata, &local->interfaces, list) {
 563                 if (!ieee80211_sdata_running(sdata))
 564                         continue;
 565
 566                 if (sdata->vif.type == NL80211_IFTYPE_STATION) {
 567                         if (sdata->u.mgd.associated) {
 568                                 associated = true;
 569
 570                                 if (sdata->vif.bss_conf.beacon_int <
 571                                     min_beacon_int || min_beacon_int == 0)
 572                                         min_beacon_int =
 573                                                 sdata->vif.bss_conf.beacon_int;
 574
 575                                 if (!qdisc_all_tx_empty(sdata->dev)) {
 576                                         tx_empty = false;
 577                                         break;
 578                                 }
 579                         }
 580                 }
 581         }
 582         mutex_unlock(&local->iflist_mtx);
 583
 584         next_chan = local->scan_req->channels[local->scan_channel_idx];
 585
 586         /*
 587          * we're currently scanning a different channel, let's
 588          * see if we can scan another channel without interfering
 589          * with the current traffic situation.
 590          *
 591          * Since we don't know if the AP has pending frames for us
 592          * we can only check for our tx queues and use the current
 593          * pm_qos requirements for rx. Hence, if no tx traffic occurs
 594          * at all we will scan as many channels in a row as the pm_qos
 595          * latency allows us to. Additionally we also check for the
 596          * currently negotiated listen interval to prevent losing
 597          * frames unnecessarily.
 598          *
 599          * Otherwise switch back to the operating channel.
 600          */
 601
 602         bad_latency = time_after(jiffies +
 603                         ieee80211_scan_get_channel_time(next_chan),
 604                         local->leave_oper_channel_time +
 605                         usecs_to_jiffies(pm_qos_request(PM_QOS_NETWORK_LATENCY)));
 606
 607         listen_int_exceeded = time_after(jiffies +
 608                         ieee80211_scan_get_channel_time(next_chan),
 609                         local->leave_oper_channel_time +
 610                         usecs_to_jiffies(min_beacon_int * 1024) *
 611                         local->hw.conf.listen_interval);
 612
 613         if (associated && !tx_empty) {
 614                 if (local->scan_req->flags & NL80211_SCAN_FLAG_LOW_PRIORITY)
 615                         next_scan_state = SCAN_ABORT;
 616                 else
 617                         next_scan_state = SCAN_SUSPEND;
 618         } else if (associated && (bad_latency || listen_int_exceeded)) {
 619                 next_scan_state = SCAN_SUSPEND;
 620         } else {
 621                 next_scan_state = SCAN_SET_CHANNEL;
 622         }
 623
 624         local->next_scan_state = next_scan_state;
 625
 626         *next_delay = 0;
 627 }
 628
 629 static void ieee80211_scan_state_set_channel(struct ieee80211_local *local,
 630                                              unsigned long *next_delay)
 631 {
 632         int skip;
 633         struct ieee80211_channel *chan;
 634
 635         skip = 0;
 636         chan = local->scan_req->channels[local->scan_channel_idx];
 637
 638         local->scan_channel = chan;
 639
 640         if (ieee80211_hw_config(local, IEEE80211_CONF_CHANGE_CHANNEL))
 641                 skip = 1;
 642
 643         /* advance state machine to next channel/band */
 644         local->scan_channel_idx++;
 645
 646         if (skip) {
 647                 /* if we skip this channel return to the decision state */
 648                 local->next_scan_state = SCAN_DECISION;
 649                 return;
 650         }
 651
 652         /*
 653          * Probe delay is used to update the NAV, cf. 11.1.3.2.2
 654          * (which unfortunately doesn't say _why_ step a) is done,
 655          * but it waits for the probe delay or until a frame is
 656          * received - and the received frame would update the NAV).
 657          * For now, we do not support waiting until a frame is
 658          * received.
 659          *
 660          * In any case, it is not necessary for a passive scan.
 661          */
 662         if (chan->flags & IEEE80211_CHAN_PASSIVE_SCAN ||
 663             !local->scan_req->n_ssids) {
 664                 *next_delay = IEEE80211_PASSIVE_CHANNEL_TIME;
 665                 local->next_scan_state = SCAN_DECISION;
 666                 return;
 667         }
 668
 669         /* active scan, send probes */
 670         *next_delay = IEEE80211_PROBE_DELAY;
 671         local->next_scan_state = SCAN_SEND_PROBE;
 672 }
 673
 674 static void ieee80211_scan_state_suspend(struct ieee80211_local *local,
 675                                          unsigned long *next_delay)
 676 {
 677         /* switch back to the operating channel */
 678         local->scan_channel = NULL;
 679         ieee80211_hw_config(local, IEEE80211_CONF_CHANGE_CHANNEL);
 680
 681         /* disable PS */
 682         ieee80211_offchannel_return(local);
 683
 684         *next_delay = HZ / 5;
 685         /* afterwards, resume scan & go to next channel */
 686         local->next_scan_state = SCAN_RESUME;
 687 }
 688
 689 static void ieee80211_scan_state_resume(struct ieee80211_local *local,
 690                                         unsigned long *next_delay)
 691 {
 692         ieee80211_offchannel_stop_vifs(local);
 693
 694         if (local->ops->flush) {
 695                 drv_flush(local, false);
 696                 *next_delay = 0;
 697         } else
 698                 *next_delay = HZ / 10;
 699
 700         /* remember when we left the operating channel */
 701         local->leave_oper_channel_time = jiffies;
 702
 703         /* advance to the next channel to be scanned */
 704         local->next_scan_state = SCAN_SET_CHANNEL;
 705 }
 706
 707 void ieee80211_scan_work(struct work_struct *work)
 708 {
 709         struct ieee80211_local *local =
 710                 container_of(work, struct ieee80211_local, scan_work.work);
 711         struct ieee80211_sub_if_data *sdata;
 712         unsigned long next_delay = 0;
 713         bool aborted, hw_scan;
 714
 715         mutex_lock(&local->mtx);
 716
 717         sdata = rcu_dereference_protected(local->scan_sdata,
 718                                           lockdep_is_held(&local->mtx));
 719
 720         /* When scanning on-channel, the first-callback means completed. */
 721         if (test_bit(SCAN_ONCHANNEL_SCANNING, &local->scanning)) {
 722                 aborted = test_and_clear_bit(SCAN_ABORTED, &local->scanning);
 723                 goto out_complete;
 724         }
 725
 726         if (test_and_clear_bit(SCAN_COMPLETED, &local->scanning)) {
 727                 aborted = test_and_clear_bit(SCAN_ABORTED, &local->scanning);
 728                 goto out_complete;
 729         }
 730
 731         if (!sdata || !local->scan_req)
 732                 goto out;
 733
 734         if (local->scan_req && !local->scanning) {
 735                 struct cfg80211_scan_request *req = local->scan_req;
 736                 int rc;
 737
 738                 local->scan_req = NULL;
 739                 rcu_assign_pointer(local->scan_sdata, NULL);
 740
 741                 rc = __ieee80211_start_scan(sdata, req);
 742                 if (rc) {
 743                         /* need to complete scan in cfg80211 */
 744                         local->scan_req = req;
 745                         aborted = true;
 746                         goto out_complete;
 747                 } else
 748                         goto out;
 749         }
 750
 751         /*
 752          * Avoid re-scheduling when the sdata is going away.
 753          */
 754         if (!ieee80211_sdata_running(sdata)) {
 755                 aborted = true;
 756                 goto out_complete;
 757         }
 758
 759         /*
 760          * as long as no delay is required advance immediately
 761          * without scheduling a new work
 762          */
 763         do {
 764                 if (!ieee80211_sdata_running(sdata)) {
 765                         aborted = true;
 766                         goto out_complete;
 767                 }
 768
 769                 switch (local->next_scan_state) {
 770                 case SCAN_DECISION:
 771                         /* if no more bands/channels left, complete scan */
 772                         if (local->scan_channel_idx >= local->scan_req->n_channels) {
 773                                 aborted = false;
 774                                 goto out_complete;
 775                         }
 776                         ieee80211_scan_state_decision(local, &next_delay);
 777                         break;
 778                 case SCAN_SET_CHANNEL:
 779                         ieee80211_scan_state_set_channel(local, &next_delay);
 780                         break;
 781                 case SCAN_SEND_PROBE:
 782                         ieee80211_scan_state_send_probe(local, &next_delay);
 783                         break;
 784                 case SCAN_SUSPEND:
 785                         ieee80211_scan_state_suspend(local, &next_delay);
 786                         break;
 787                 case SCAN_RESUME:
 788                         ieee80211_scan_state_resume(local, &next_delay);
 789                         break;
 790                 case SCAN_ABORT:
 791                         aborted = true;
 792                         goto out_complete;
 793                 }
 794         } while (next_delay == 0);
 795
 796         ieee80211_queue_delayed_work(&local->hw, &local->scan_work, next_delay);
 797         goto out;
 798
 799 out_complete:
 800         hw_scan = test_bit(SCAN_HW_SCANNING, &local->scanning);
 801         __ieee80211_scan_completed(&local->hw, aborted, hw_scan);
 802 out:
 803         mutex_unlock(&local->mtx);
 804 }
 805
 806 int ieee80211_request_scan(struct ieee80211_sub_if_data *sdata,
 807                            struct cfg80211_scan_request *req)
 808 {
 809         int res;
 810
 811         mutex_lock(&sdata->local->mtx);
 812         res = __ieee80211_start_scan(sdata, req);
 813         mutex_unlock(&sdata->local->mtx);
 814
 815         return res;
 816 }
 817
 818 int ieee80211_request_ibss_scan(struct ieee80211_sub_if_data *sdata,
 819                                 const u8 *ssid, u8 ssid_len,
 820                                 struct ieee80211_channel *chan)
 821 {
 822         struct ieee80211_local *local = sdata->local;
 823         int ret = -EBUSY;
 824         enum ieee80211_band band;
 825
 826         mutex_lock(&local->mtx);
 827
 828         /* busy scanning */
 829         if (local->scan_req)
 830                 goto unlock;
 831
 832         /* fill internal scan request */
 833         if (!chan) {
 834                 int i, max_n;
 835                 int n_ch = 0;
 836
 837                 for (band = 0; band < IEEE80211_NUM_BANDS; band++) {
 838                         if (!local->hw.wiphy->bands[band])
 839                                 continue;
 840
 841                         max_n = local->hw.wiphy->bands[band]->n_channels;
 842                         for (i = 0; i < max_n; i++) {
 843                                 struct ieee80211_channel *tmp_ch =
 844                                     &local->hw.wiphy->bands[band]->channels[i];
 845
 846                                 if (tmp_ch->flags & (IEEE80211_CHAN_NO_IBSS |
 847                                                      IEEE80211_CHAN_DISABLED))
 848                                         continue;
 849
 850                                 local->int_scan_req->channels[n_ch] = tmp_ch;
 851                                 n_ch++;
 852                         }
 853                 }
 854
 855                 if (WARN_ON_ONCE(n_ch == 0))
 856                         goto unlock;
 857
 858                 local->int_scan_req->n_channels = n_ch;
 859         } else {
 860                 if (WARN_ON_ONCE(chan->flags & (IEEE80211_CHAN_NO_IBSS |
 861                                                 IEEE80211_CHAN_DISABLED)))
 862                         goto unlock;
 863
 864                 local->int_scan_req->channels[0] = chan;
 865                 local->int_scan_req->n_channels = 1;
 866         }
 867
 868         local->int_scan_req->ssids = &local->scan_ssid;
 869         local->int_scan_req->n_ssids = 1;
 870         memcpy(local->int_scan_req->ssids[0].ssid, ssid, IEEE80211_MAX_SSID_LEN);
 871         local->int_scan_req->ssids[0].ssid_len = ssid_len;
 872
 873         ret = __ieee80211_start_scan(sdata, sdata->local->int_scan_req);
 874  unlock:
 875         mutex_unlock(&local->mtx);
 876         return ret;
 877 }
 878
 879 /*
 880  * Only call this function when a scan can't be queued -- under RTNL.
 881  */
 882 void ieee80211_scan_cancel(struct ieee80211_local *local)
 883 {
 884         /*
 885          * We are canceling software scan, or deferred scan that was not
 886          * yet really started (see __ieee80211_start_scan ).
 887          *
 888          * Regarding hardware scan:
 889          * - we can not call  __ieee80211_scan_completed() as when
 890          *   SCAN_HW_SCANNING bit is set this function change
 891          *   local->hw_scan_req to operate on 5G band, what race with
 892          *   driver which can use local->hw_scan_req
 893          *
 894          * - we can not cancel scan_work since driver can schedule it
 895          *   by ieee80211_scan_completed(..., true) to finish scan
 896          *
 897          * Hence we only call the cancel_hw_scan() callback, but the low-level
 898          * driver is still responsible for calling ieee80211_scan_completed()
 899          * after the scan was completed/aborted.
 900          */
 901
 902         mutex_lock(&local->mtx);
 903         if (!local->scan_req)
 904                 goto out;
 905
 906         if (test_bit(SCAN_HW_SCANNING, &local->scanning)) {
 907                 if (local->ops->cancel_hw_scan)
 908                         drv_cancel_hw_scan(local,
 909                                 rcu_dereference_protected(local->scan_sdata,
 910                                                 lockdep_is_held(&local->mtx)));
 911                 goto out;
 912         }
 913
 914         /*
 915          * If the work is currently running, it must be blocked on
 916          * the mutex, but we'll set scan_sdata = NULL and it'll
 917          * simply exit once it acquires the mutex.
 918          */
 919         cancel_delayed_work(&local->scan_work);
 920         /* and clean up */
 921         __ieee80211_scan_completed(&local->hw, true, false);
 922 out:
 923         mutex_unlock(&local->mtx);
 924 }
 925
 926 int ieee80211_request_sched_scan_start(struct ieee80211_sub_if_data *sdata,
 927                                        struct cfg80211_sched_scan_request *req)
 928 {
 929         struct ieee80211_local *local = sdata->local;
 930         struct ieee80211_sched_scan_ies sched_scan_ies = {};
 931         int ret, i, iebufsz;
 932
 933         iebufsz = 2 + IEEE80211_MAX_SSID_LEN +
 934                   local->scan_ies_len + req->ie_len;
 935
 936         mutex_lock(&local->mtx);
 937
 938         if (rcu_access_pointer(local->sched_scan_sdata)) {
 939                 ret = -EBUSY;
 940                 goto out;
 941         }
 942
 943         if (!local->ops->sched_scan_start) {
 944                 ret = -ENOTSUPP;
 945                 goto out;
 946         }
 947
 948         for (i = 0; i < IEEE80211_NUM_BANDS; i++) {
 949                 if (!local->hw.wiphy->bands[i])
 950                         continue;
 951
 952                 sched_scan_ies.ie[i] = kzalloc(iebufsz, GFP_KERNEL);
 953                 if (!sched_scan_ies.ie[i]) {
 954                         ret = -ENOMEM;
 955                         goto out_free;
 956                 }
 957
 958                 sched_scan_ies.len[i] =
 959                         ieee80211_build_preq_ies(local, sched_scan_ies.ie[i],
 960                                                  iebufsz, req->ie, req->ie_len,
 961                                                  i, (u32) -1, 0);
 962         }
 963
 964         ret = drv_sched_scan_start(local, sdata, req, &sched_scan_ies);
 965         if (ret == 0)
 966                 rcu_assign_pointer(local->sched_scan_sdata, sdata);
 967
 968 out_free:
 969         while (i > 0)
 970                 kfree(sched_scan_ies.ie[--i]);
 971 out:
 972         mutex_unlock(&local->mtx);
 973         return ret;
 974 }
 975
 976 int ieee80211_request_sched_scan_stop(struct ieee80211_sub_if_data *sdata)
 977 {
 978         struct ieee80211_local *local = sdata->local;
 979         int ret = 0;
 980
 981         mutex_lock(&local->mtx);
 982
 983         if (!local->ops->sched_scan_stop) {
 984                 ret = -ENOTSUPP;
 985                 goto out;
 986         }
 987
 988         if (rcu_access_pointer(local->sched_scan_sdata))
 989                 drv_sched_scan_stop(local, sdata);
 990
 991 out:
 992         mutex_unlock(&local->mtx);
 993
 994         return ret;
 995 }
 996
 997 void ieee80211_sched_scan_results(struct ieee80211_hw *hw)
 998 {
 999         struct ieee80211_local *local = hw_to_local(hw);
1000
1001         trace_api_sched_scan_results(local);
1002
1003         cfg80211_sched_scan_results(hw->wiphy);
1004 }
1005 EXPORT_SYMBOL(ieee80211_sched_scan_results);
1006
1007 void ieee80211_sched_scan_stopped_work(struct work_struct *work)
1008 {
1009         struct ieee80211_local *local =
1010                 container_of(work, struct ieee80211_local,
1011                              sched_scan_stopped_work);
1012
1013         mutex_lock(&local->mtx);
1014
1015         if (!rcu_access_pointer(local->sched_scan_sdata)) {
1016                 mutex_unlock(&local->mtx);
1017                 return;
1018         }
1019
1020         rcu_assign_pointer(local->sched_scan_sdata, NULL);
1021
1022         mutex_unlock(&local->mtx);
1023
1024         cfg80211_sched_scan_stopped(local->hw.wiphy);
1025 }
1026
1027 void ieee80211_sched_scan_stopped(struct ieee80211_hw *hw)
1028 {
1029         struct ieee80211_local *local = hw_to_local(hw);
1030
1031         trace_api_sched_scan_stopped(local);
1032
1033         ieee80211_queue_work(&local->hw, &local->sched_scan_stopped_work);
1034 }
1035 EXPORT_SYMBOL(ieee80211_sched_scan_stopped);