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 struct ieee80211_bss *
  33 ieee80211_rx_bss_get(struct ieee80211_local *local, u8 *bssid, int freq,
  34                      u8 *ssid, u8 ssid_len)
  35 {
  36         struct cfg80211_bss *cbss;
  37
  38         cbss = cfg80211_get_bss(local->hw.wiphy,
  39                                 ieee80211_get_channel(local->hw.wiphy, freq),
  40                                 bssid, ssid, ssid_len, 0, 0);
  41         if (!cbss)
  42                 return NULL;
  43         return (void *)cbss->priv;
  44 }
  45
  46 static void ieee80211_rx_bss_free(struct cfg80211_bss *cbss)
  47 {
  48         struct ieee80211_bss *bss = (void *)cbss->priv;
  49
  50         kfree(bss_mesh_id(bss));
  51         kfree(bss_mesh_cfg(bss));
  52 }
  53
  54 void ieee80211_rx_bss_put(struct ieee80211_local *local,
  55                           struct ieee80211_bss *bss)
  56 {
  57         if (!bss)
  58                 return;
  59         cfg80211_put_bss(container_of((void *)bss, struct cfg80211_bss, priv));
  60 }
  61
  62 static bool is_uapsd_supported(struct ieee802_11_elems *elems)
  63 {
  64         u8 qos_info;
  65
  66         if (elems->wmm_info && elems->wmm_info_len == 7
  67             && elems->wmm_info[5] == 1)
  68                 qos_info = elems->wmm_info[6];
  69         else if (elems->wmm_param && elems->wmm_param_len == 24
  70                  && elems->wmm_param[5] == 1)
  71                 qos_info = elems->wmm_param[6];
  72         else
  73                 /* no valid wmm information or parameter element found */
  74                 return false;
  75
  76         return qos_info & IEEE80211_WMM_IE_AP_QOSINFO_UAPSD;
  77 }
  78
  79 struct ieee80211_bss *
  80 ieee80211_bss_info_update(struct ieee80211_local *local,
  81                           struct ieee80211_rx_status *rx_status,
  82                           struct ieee80211_mgmt *mgmt,
  83                           size_t len,
  84                           struct ieee802_11_elems *elems,
  85                           struct ieee80211_channel *channel,
  86                           bool beacon)
  87 {
  88         struct cfg80211_bss *cbss;
  89         struct ieee80211_bss *bss;
  90         int clen, srlen;
  91         s32 signal = 0;
  92
  93         if (local->hw.flags & IEEE80211_HW_SIGNAL_DBM)
  94                 signal = rx_status->signal * 100;
  95         else if (local->hw.flags & IEEE80211_HW_SIGNAL_UNSPEC)
  96                 signal = (rx_status->signal * 100) / local->hw.max_signal;
  97
  98         cbss = cfg80211_inform_bss_frame(local->hw.wiphy, channel,
  99                                          mgmt, len, signal, GFP_ATOMIC);
 100
 101         if (!cbss)
 102                 return NULL;
 103
 104         cbss->free_priv = ieee80211_rx_bss_free;
 105         bss = (void *)cbss->priv;
 106
 107         if (elems->parse_error) {
 108                 if (beacon)
 109                         bss->corrupt_data |= IEEE80211_BSS_CORRUPT_BEACON;
 110                 else
 111                         bss->corrupt_data |= IEEE80211_BSS_CORRUPT_PROBE_RESP;
 112         } else {
 113                 if (beacon)
 114                         bss->corrupt_data &= ~IEEE80211_BSS_CORRUPT_BEACON;
 115                 else
 116                         bss->corrupt_data &= ~IEEE80211_BSS_CORRUPT_PROBE_RESP;
 117         }
 118
 119         /* save the ERP value so that it is available at association time */
 120         if (elems->erp_info && elems->erp_info_len >= 1 &&
 121                         (!elems->parse_error ||
 122                          !(bss->valid_data & IEEE80211_BSS_VALID_ERP))) {
 123                 bss->erp_value = elems->erp_info[0];
 124                 bss->has_erp_value = true;
 125                 if (!elems->parse_error)
 126                         bss->valid_data |= IEEE80211_BSS_VALID_ERP;
 127         }
 128
 129         if (elems->tim && (!elems->parse_error ||
 130                            !(bss->valid_data & IEEE80211_BSS_VALID_DTIM))) {
 131                 struct ieee80211_tim_ie *tim_ie =
 132                         (struct ieee80211_tim_ie *)elems->tim;
 133                 bss->dtim_period = tim_ie->dtim_period;
 134                 if (!elems->parse_error)
 135                                 bss->valid_data |= IEEE80211_BSS_VALID_DTIM;
 136         }
 137
 138         /* If the beacon had no TIM IE, or it was invalid, use 1 */
 139         if (beacon && !bss->dtim_period)
 140                 bss->dtim_period = 1;
 141
 142         /* replace old supported rates if we get new values */
 143         if (!elems->parse_error ||
 144             !(bss->valid_data & IEEE80211_BSS_VALID_RATES)) {
 145                 srlen = 0;
 146                 if (elems->supp_rates) {
 147                         clen = IEEE80211_MAX_SUPP_RATES;
 148                         if (clen > elems->supp_rates_len)
 149                                 clen = elems->supp_rates_len;
 150                         memcpy(bss->supp_rates, elems->supp_rates, clen);
 151                         srlen += clen;
 152                 }
 153                 if (elems->ext_supp_rates) {
 154                         clen = IEEE80211_MAX_SUPP_RATES - srlen;
 155                         if (clen > elems->ext_supp_rates_len)
 156                                 clen = elems->ext_supp_rates_len;
 157                         memcpy(bss->supp_rates + srlen, elems->ext_supp_rates,
 158                                clen);
 159                         srlen += clen;
 160                 }
 161                 if (srlen) {
 162                         bss->supp_rates_len = srlen;
 163                         if (!elems->parse_error)
 164                                 bss->valid_data |= IEEE80211_BSS_VALID_RATES;
 165                 }
 166         }
 167
 168         if (!elems->parse_error ||
 169             !(bss->valid_data & IEEE80211_BSS_VALID_WMM)) {
 170                 bss->wmm_used = elems->wmm_param || elems->wmm_info;
 171                 bss->uapsd_supported = is_uapsd_supported(elems);
 172                 if (!elems->parse_error)
 173                         bss->valid_data |= IEEE80211_BSS_VALID_WMM;
 174         }
 175
 176         if (!beacon)
 177                 bss->last_probe_resp = jiffies;
 178
 179         return bss;
 180 }
 181
 182 ieee80211_rx_result
 183 ieee80211_scan_rx(struct ieee80211_sub_if_data *sdata, struct sk_buff *skb)
 184 {
 185         struct ieee80211_rx_status *rx_status = IEEE80211_SKB_RXCB(skb);
 186         struct ieee80211_mgmt *mgmt;
 187         struct ieee80211_bss *bss;
 188         u8 *elements;
 189         struct ieee80211_channel *channel;
 190         size_t baselen;
 191         int freq;
 192         __le16 fc;
 193         bool presp, beacon = false;
 194         struct ieee802_11_elems elems;
 195
 196         if (skb->len < 2)
 197                 return RX_DROP_UNUSABLE;
 198
 199         mgmt = (struct ieee80211_mgmt *) skb->data;
 200         fc = mgmt->frame_control;
 201
 202         if (ieee80211_is_ctl(fc))
 203                 return RX_CONTINUE;
 204
 205         if (skb->len < 24)
 206                 return RX_CONTINUE;
 207
 208         presp = ieee80211_is_probe_resp(fc);
 209         if (presp) {
 210                 /* ignore ProbeResp to foreign address */
 211                 if (compare_ether_addr(mgmt->da, sdata->vif.addr))
 212                         return RX_DROP_MONITOR;
 213
 214                 presp = true;
 215                 elements = mgmt->u.probe_resp.variable;
 216                 baselen = offsetof(struct ieee80211_mgmt, u.probe_resp.variable);
 217         } else {
 218                 beacon = ieee80211_is_beacon(fc);
 219                 baselen = offsetof(struct ieee80211_mgmt, u.beacon.variable);
 220                 elements = mgmt->u.beacon.variable;
 221         }
 222
 223         if (!presp && !beacon)
 224                 return RX_CONTINUE;
 225
 226         if (baselen > skb->len)
 227                 return RX_DROP_MONITOR;
 228
 229         ieee802_11_parse_elems(elements, skb->len - baselen, &elems);
 230
 231         if (elems.ds_params && elems.ds_params_len == 1)
 232                 freq = ieee80211_channel_to_frequency(elems.ds_params[0],
 233                                                       rx_status->band);
 234         else
 235                 freq = rx_status->freq;
 236
 237         channel = ieee80211_get_channel(sdata->local->hw.wiphy, freq);
 238
 239         if (!channel || channel->flags & IEEE80211_CHAN_DISABLED)
 240                 return RX_DROP_MONITOR;
 241
 242         bss = ieee80211_bss_info_update(sdata->local, rx_status,
 243                                         mgmt, skb->len, &elems,
 244                                         channel, beacon);
 245         if (bss)
 246                 ieee80211_rx_bss_put(sdata->local, bss);
 247
 248         if (channel == sdata->local->oper_channel)
 249                 return RX_CONTINUE;
 250
 251         dev_kfree_skb(skb);
 252         return RX_QUEUED;
 253 }
 254
 255 /* return false if no more work */
 256 static bool ieee80211_prep_hw_scan(struct ieee80211_local *local)
 257 {
 258         struct cfg80211_scan_request *req = local->scan_req;
 259         enum ieee80211_band band;
 260         int i, ielen, n_chans;
 261
 262         do {
 263                 if (local->hw_scan_band == IEEE80211_NUM_BANDS)
 264                         return false;
 265
 266                 band = local->hw_scan_band;
 267                 n_chans = 0;
 268                 for (i = 0; i < req->n_channels; i++) {
 269                         if (req->channels[i]->band == band) {
 270                                 local->hw_scan_req->channels[n_chans] =
 271                                                         req->channels[i];
 272                                 n_chans++;
 273                         }
 274                 }
 275
 276                 local->hw_scan_band++;
 277         } while (!n_chans);
 278
 279         local->hw_scan_req->n_channels = n_chans;
 280
 281         ielen = ieee80211_build_preq_ies(local, (u8 *)local->hw_scan_req->ie,
 282                                          req->ie, req->ie_len, band,
 283                                          req->rates[band], 0);
 284         local->hw_scan_req->ie_len = ielen;
 285         local->hw_scan_req->no_cck = req->no_cck;
 286
 287         return true;
 288 }
 289
 290 static void __ieee80211_scan_completed(struct ieee80211_hw *hw, bool aborted,
 291                                        bool was_hw_scan)
 292 {
 293         struct ieee80211_local *local = hw_to_local(hw);
 294
 295         lockdep_assert_held(&local->mtx);
 296
 297         /*
 298          * It's ok to abort a not-yet-running scan (that
 299          * we have one at all will be verified by checking
 300          * local->scan_req next), but not to complete it
 301          * successfully.
 302          */
 303         if (WARN_ON(!local->scanning && !aborted))
 304                 aborted = true;
 305
 306         if (WARN_ON(!local->scan_req))
 307                 return;
 308
 309         if (was_hw_scan && !aborted && ieee80211_prep_hw_scan(local)) {
 310                 int rc = drv_hw_scan(local, local->scan_sdata, local->hw_scan_req);
 311                 if (rc == 0)
 312                         return;
 313         }
 314
 315         kfree(local->hw_scan_req);
 316         local->hw_scan_req = NULL;
 317
 318         if (local->scan_req != local->int_scan_req)
 319                 cfg80211_scan_done(local->scan_req, aborted);
 320         local->scan_req = NULL;
 321         local->scan_sdata = NULL;
 322
 323         local->scanning = 0;
 324         local->scan_channel = NULL;
 325
 326         /* Set power back to normal operating levels. */
 327         ieee80211_hw_config(local, 0);
 328
 329         if (!was_hw_scan) {
 330                 ieee80211_configure_filter(local);
 331                 drv_sw_scan_complete(local);
 332                 ieee80211_offchannel_return(local, true);
 333         }
 334
 335         ieee80211_recalc_idle(local);
 336
 337         ieee80211_mlme_notify_scan_completed(local);
 338         ieee80211_ibss_notify_scan_completed(local);
 339         ieee80211_mesh_notify_scan_completed(local);
 340         ieee80211_queue_work(&local->hw, &local->work_work);
 341 }
 342
 343 void ieee80211_scan_completed(struct ieee80211_hw *hw, bool aborted)
 344 {
 345         struct ieee80211_local *local = hw_to_local(hw);
 346
 347         trace_api_scan_completed(local, aborted);
 348
 349         set_bit(SCAN_COMPLETED, &local->scanning);
 350         if (aborted)
 351                 set_bit(SCAN_ABORTED, &local->scanning);
 352         ieee80211_queue_delayed_work(&local->hw, &local->scan_work, 0);
 353 }
 354 EXPORT_SYMBOL(ieee80211_scan_completed);
 355
 356 static int ieee80211_start_sw_scan(struct ieee80211_local *local)
 357 {
 358         /*
 359          * Hardware/driver doesn't support hw_scan, so use software
 360          * scanning instead. First send a nullfunc frame with power save
 361          * bit on so that AP will buffer the frames for us while we are not
 362          * listening, then send probe requests to each channel and wait for
 363          * the responses. After all channels are scanned, tune back to the
 364          * original channel and send a nullfunc frame with power save bit
 365          * off to trigger the AP to send us all the buffered frames.
 366          *
 367          * Note that while local->sw_scanning is true everything else but
 368          * nullfunc frames and probe requests will be dropped in
 369          * ieee80211_tx_h_check_assoc().
 370          */
 371         drv_sw_scan_start(local);
 372
 373         local->leave_oper_channel_time = jiffies;
 374         local->next_scan_state = SCAN_DECISION;
 375         local->scan_channel_idx = 0;
 376
 377         ieee80211_offchannel_stop_vifs(local, true);
 378
 379         ieee80211_configure_filter(local);
 380
 381         /* We need to set power level at maximum rate for scanning. */
 382         ieee80211_hw_config(local, 0);
 383
 384         ieee80211_queue_delayed_work(&local->hw,
 385                                      &local->scan_work, 0);
 386
 387         return 0;
 388 }
 389
 390
 391 static int __ieee80211_start_scan(struct ieee80211_sub_if_data *sdata,
 392                                   struct cfg80211_scan_request *req)
 393 {
 394         struct ieee80211_local *local = sdata->local;
 395         int rc;
 396
 397         lockdep_assert_held(&local->mtx);
 398
 399         if (local->scan_req)
 400                 return -EBUSY;
 401
 402         if (!list_empty(&local->work_list)) {
 403                 /* wait for the work to finish/time out */
 404                 local->scan_req = req;
 405                 local->scan_sdata = sdata;
 406                 return 0;
 407         }
 408
 409         if (local->ops->hw_scan) {
 410                 u8 *ies;
 411
 412                 local->hw_scan_req = kmalloc(
 413                                 sizeof(*local->hw_scan_req) +
 414                                 req->n_channels * sizeof(req->channels[0]) +
 415                                 2 + IEEE80211_MAX_SSID_LEN + local->scan_ies_len +
 416                                 req->ie_len, GFP_KERNEL);
 417                 if (!local->hw_scan_req)
 418                         return -ENOMEM;
 419
 420                 local->hw_scan_req->ssids = req->ssids;
 421                 local->hw_scan_req->n_ssids = req->n_ssids;
 422                 ies = (u8 *)local->hw_scan_req +
 423                         sizeof(*local->hw_scan_req) +
 424                         req->n_channels * sizeof(req->channels[0]);
 425                 local->hw_scan_req->ie = ies;
 426
 427                 local->hw_scan_band = 0;
 428
 429                 /*
 430                  * After allocating local->hw_scan_req, we must
 431                  * go through until ieee80211_prep_hw_scan(), so
 432                  * anything that might be changed here and leave
 433                  * this function early must not go after this
 434                  * allocation.
 435                  */
 436         }
 437
 438         local->scan_req = req;
 439         local->scan_sdata = sdata;
 440
 441         if (local->ops->hw_scan)
 442                 __set_bit(SCAN_HW_SCANNING, &local->scanning);
 443         else
 444                 __set_bit(SCAN_SW_SCANNING, &local->scanning);
 445
 446         ieee80211_recalc_idle(local);
 447
 448         if (local->ops->hw_scan) {
 449                 WARN_ON(!ieee80211_prep_hw_scan(local));
 450                 rc = drv_hw_scan(local, sdata, local->hw_scan_req);
 451         } else
 452                 rc = ieee80211_start_sw_scan(local);
 453
 454         if (rc) {
 455                 kfree(local->hw_scan_req);
 456                 local->hw_scan_req = NULL;
 457                 local->scanning = 0;
 458
 459                 ieee80211_recalc_idle(local);
 460
 461                 local->scan_req = NULL;
 462                 local->scan_sdata = NULL;
 463         }
 464
 465         return rc;
 466 }
 467
 468 static unsigned long
 469 ieee80211_scan_get_channel_time(struct ieee80211_channel *chan)
 470 {
 471         /*
 472          * TODO: channel switching also consumes quite some time,
 473          * add that delay as well to get a better estimation
 474          */
 475         if (chan->flags & IEEE80211_CHAN_PASSIVE_SCAN)
 476                 return IEEE80211_PASSIVE_CHANNEL_TIME;
 477         return IEEE80211_PROBE_DELAY + IEEE80211_CHANNEL_TIME;
 478 }
 479
 480 static void ieee80211_scan_state_decision(struct ieee80211_local *local,
 481                                           unsigned long *next_delay)
 482 {
 483         bool associated = false;
 484         bool tx_empty = true;
 485         bool bad_latency;
 486         bool listen_int_exceeded;
 487         unsigned long min_beacon_int = 0;
 488         struct ieee80211_sub_if_data *sdata;
 489         struct ieee80211_channel *next_chan;
 490
 491         /*
 492          * check if at least one STA interface is associated,
 493          * check if at least one STA interface has pending tx frames
 494          * and grab the lowest used beacon interval
 495          */
 496         mutex_lock(&local->iflist_mtx);
 497         list_for_each_entry(sdata, &local->interfaces, list) {
 498                 if (!ieee80211_sdata_running(sdata))
 499                         continue;
 500
 501                 if (sdata->vif.type == NL80211_IFTYPE_STATION) {
 502                         if (sdata->u.mgd.associated) {
 503                                 associated = true;
 504
 505                                 if (sdata->vif.bss_conf.beacon_int <
 506                                     min_beacon_int || min_beacon_int == 0)
 507                                         min_beacon_int =
 508                                                 sdata->vif.bss_conf.beacon_int;
 509
 510                                 if (!qdisc_all_tx_empty(sdata->dev)) {
 511                                         tx_empty = false;
 512                                         break;
 513                                 }
 514                         }
 515                 }
 516         }
 517         mutex_unlock(&local->iflist_mtx);
 518
 519         next_chan = local->scan_req->channels[local->scan_channel_idx];
 520
 521         /*
 522          * we're currently scanning a different channel, let's
 523          * see if we can scan another channel without interfering
 524          * with the current traffic situation.
 525          *
 526          * Since we don't know if the AP has pending frames for us
 527          * we can only check for our tx queues and use the current
 528          * pm_qos requirements for rx. Hence, if no tx traffic occurs
 529          * at all we will scan as many channels in a row as the pm_qos
 530          * latency allows us to. Additionally we also check for the
 531          * currently negotiated listen interval to prevent losing
 532          * frames unnecessarily.
 533          *
 534          * Otherwise switch back to the operating channel.
 535          */
 536
 537         bad_latency = time_after(jiffies +
 538                         ieee80211_scan_get_channel_time(next_chan),
 539                         local->leave_oper_channel_time +
 540                         usecs_to_jiffies(pm_qos_request(PM_QOS_NETWORK_LATENCY)));
 541
 542         listen_int_exceeded = time_after(jiffies +
 543                         ieee80211_scan_get_channel_time(next_chan),
 544                         local->leave_oper_channel_time +
 545                         usecs_to_jiffies(min_beacon_int * 1024) *
 546                         local->hw.conf.listen_interval);
 547
 548         if (associated && (!tx_empty || bad_latency || listen_int_exceeded))
 549                 local->next_scan_state = SCAN_SUSPEND;
 550         else
 551                 local->next_scan_state = SCAN_SET_CHANNEL;
 552
 553         *next_delay = 0;
 554 }
 555
 556 static void ieee80211_scan_state_set_channel(struct ieee80211_local *local,
 557                                              unsigned long *next_delay)
 558 {
 559         int skip;
 560         struct ieee80211_channel *chan;
 561
 562         skip = 0;
 563         chan = local->scan_req->channels[local->scan_channel_idx];
 564
 565         local->scan_channel = chan;
 566
 567         if (ieee80211_hw_config(local, IEEE80211_CONF_CHANGE_CHANNEL))
 568                 skip = 1;
 569
 570         /* advance state machine to next channel/band */
 571         local->scan_channel_idx++;
 572
 573         if (skip) {
 574                 /* if we skip this channel return to the decision state */
 575                 local->next_scan_state = SCAN_DECISION;
 576                 return;
 577         }
 578
 579         /*
 580          * Probe delay is used to update the NAV, cf. 11.1.3.2.2
 581          * (which unfortunately doesn't say _why_ step a) is done,
 582          * but it waits for the probe delay or until a frame is
 583          * received - and the received frame would update the NAV).
 584          * For now, we do not support waiting until a frame is
 585          * received.
 586          *
 587          * In any case, it is not necessary for a passive scan.
 588          */
 589         if (chan->flags & IEEE80211_CHAN_PASSIVE_SCAN ||
 590             !local->scan_req->n_ssids) {
 591                 *next_delay = IEEE80211_PASSIVE_CHANNEL_TIME;
 592                 local->next_scan_state = SCAN_DECISION;
 593                 return;
 594         }
 595
 596         /* active scan, send probes */
 597         *next_delay = IEEE80211_PROBE_DELAY;
 598         local->next_scan_state = SCAN_SEND_PROBE;
 599 }
 600
 601 static void ieee80211_scan_state_send_probe(struct ieee80211_local *local,
 602                                             unsigned long *next_delay)
 603 {
 604         int i;
 605         struct ieee80211_sub_if_data *sdata = local->scan_sdata;
 606         enum ieee80211_band band = local->hw.conf.channel->band;
 607
 608         for (i = 0; i < local->scan_req->n_ssids; i++)
 609                 ieee80211_send_probe_req(
 610                         sdata, NULL,
 611                         local->scan_req->ssids[i].ssid,
 612                         local->scan_req->ssids[i].ssid_len,
 613                         local->scan_req->ie, local->scan_req->ie_len,
 614                         local->scan_req->rates[band], false,
 615                         local->scan_req->no_cck);
 616
 617         /*
 618          * After sending probe requests, wait for probe responses
 619          * on the channel.
 620          */
 621         *next_delay = IEEE80211_CHANNEL_TIME;
 622         local->next_scan_state = SCAN_DECISION;
 623 }
 624
 625 static void ieee80211_scan_state_suspend(struct ieee80211_local *local,
 626                                          unsigned long *next_delay)
 627 {
 628         /* switch back to the operating channel */
 629         local->scan_channel = NULL;
 630         ieee80211_hw_config(local, IEEE80211_CONF_CHANGE_CHANNEL);
 631
 632         /*
 633          * Re-enable vifs and beaconing.  Leave PS
 634          * in off-channel state..will put that back
 635          * on-channel at the end of scanning.
 636          */
 637         ieee80211_offchannel_return(local, false);
 638
 639         *next_delay = HZ / 5;
 640         /* afterwards, resume scan & go to next channel */
 641         local->next_scan_state = SCAN_RESUME;
 642 }
 643
 644 static void ieee80211_scan_state_resume(struct ieee80211_local *local,
 645                                         unsigned long *next_delay)
 646 {
 647         /* PS already is in off-channel mode */
 648         ieee80211_offchannel_stop_vifs(local, false);
 649
 650         if (local->ops->flush) {
 651                 drv_flush(local, false);
 652                 *next_delay = 0;
 653         } else
 654                 *next_delay = HZ / 10;
 655
 656         /* remember when we left the operating channel */
 657         local->leave_oper_channel_time = jiffies;
 658
 659         /* advance to the next channel to be scanned */
 660         local->next_scan_state = SCAN_SET_CHANNEL;
 661 }
 662
 663 void ieee80211_scan_work(struct work_struct *work)
 664 {
 665         struct ieee80211_local *local =
 666                 container_of(work, struct ieee80211_local, scan_work.work);
 667         struct ieee80211_sub_if_data *sdata;
 668         unsigned long next_delay = 0;
 669         bool aborted, hw_scan;
 670
 671         mutex_lock(&local->mtx);
 672
 673         sdata = local->scan_sdata;
 674
 675         if (test_and_clear_bit(SCAN_COMPLETED, &local->scanning)) {
 676                 aborted = test_and_clear_bit(SCAN_ABORTED, &local->scanning);
 677                 goto out_complete;
 678         }
 679
 680         if (!sdata || !local->scan_req)
 681                 goto out;
 682
 683         if (local->scan_req && !local->scanning) {
 684                 struct cfg80211_scan_request *req = local->scan_req;
 685                 int rc;
 686
 687                 local->scan_req = NULL;
 688                 local->scan_sdata = NULL;
 689
 690                 rc = __ieee80211_start_scan(sdata, req);
 691                 if (rc) {
 692                         /* need to complete scan in cfg80211 */
 693                         local->scan_req = req;
 694                         aborted = true;
 695                         goto out_complete;
 696                 } else
 697                         goto out;
 698         }
 699
 700         /*
 701          * Avoid re-scheduling when the sdata is going away.
 702          */
 703         if (!ieee80211_sdata_running(sdata)) {
 704                 aborted = true;
 705                 goto out_complete;
 706         }
 707
 708         /*
 709          * as long as no delay is required advance immediately
 710          * without scheduling a new work
 711          */
 712         do {
 713                 if (!ieee80211_sdata_running(sdata)) {
 714                         aborted = true;
 715                         goto out_complete;
 716                 }
 717
 718                 switch (local->next_scan_state) {
 719                 case SCAN_DECISION:
 720                         /* if no more bands/channels left, complete scan */
 721                         if (local->scan_channel_idx >= local->scan_req->n_channels) {
 722                                 aborted = false;
 723                                 goto out_complete;
 724                         }
 725                         ieee80211_scan_state_decision(local, &next_delay);
 726                         break;
 727                 case SCAN_SET_CHANNEL:
 728                         ieee80211_scan_state_set_channel(local, &next_delay);
 729                         break;
 730                 case SCAN_SEND_PROBE:
 731                         ieee80211_scan_state_send_probe(local, &next_delay);
 732                         break;
 733                 case SCAN_SUSPEND:
 734                         ieee80211_scan_state_suspend(local, &next_delay);
 735                         break;
 736                 case SCAN_RESUME:
 737                         ieee80211_scan_state_resume(local, &next_delay);
 738                         break;
 739                 }
 740         } while (next_delay == 0);
 741
 742         ieee80211_queue_delayed_work(&local->hw, &local->scan_work, next_delay);
 743         goto out;
 744
 745 out_complete:
 746         hw_scan = test_bit(SCAN_HW_SCANNING, &local->scanning);
 747         __ieee80211_scan_completed(&local->hw, aborted, hw_scan);
 748 out:
 749         mutex_unlock(&local->mtx);
 750 }
 751
 752 int ieee80211_request_scan(struct ieee80211_sub_if_data *sdata,
 753                            struct cfg80211_scan_request *req)
 754 {
 755         int res;
 756
 757         mutex_lock(&sdata->local->mtx);
 758         res = __ieee80211_start_scan(sdata, req);
 759         mutex_unlock(&sdata->local->mtx);
 760
 761         return res;
 762 }
 763
 764 int ieee80211_request_internal_scan(struct ieee80211_sub_if_data *sdata,
 765                                     const u8 *ssid, u8 ssid_len,
 766                                     struct ieee80211_channel *chan)
 767 {
 768         struct ieee80211_local *local = sdata->local;
 769         int ret = -EBUSY;
 770         enum ieee80211_band band;
 771
 772         mutex_lock(&local->mtx);
 773
 774         /* busy scanning */
 775         if (local->scan_req)
 776                 goto unlock;
 777
 778         /* fill internal scan request */
 779         if (!chan) {
 780                 int i, nchan = 0;
 781
 782                 for (band = 0; band < IEEE80211_NUM_BANDS; band++) {
 783                         if (!local->hw.wiphy->bands[band])
 784                                 continue;
 785                         for (i = 0;
 786                              i < local->hw.wiphy->bands[band]->n_channels;
 787                              i++) {
 788                                 local->int_scan_req->channels[nchan] =
 789                                     &local->hw.wiphy->bands[band]->channels[i];
 790                                 nchan++;
 791                         }
 792                 }
 793
 794                 local->int_scan_req->n_channels = nchan;
 795         } else {
 796                 local->int_scan_req->channels[0] = chan;
 797                 local->int_scan_req->n_channels = 1;
 798         }
 799
 800         local->int_scan_req->ssids = &local->scan_ssid;
 801         local->int_scan_req->n_ssids = 1;
 802         memcpy(local->int_scan_req->ssids[0].ssid, ssid, IEEE80211_MAX_SSID_LEN);
 803         local->int_scan_req->ssids[0].ssid_len = ssid_len;
 804
 805         ret = __ieee80211_start_scan(sdata, sdata->local->int_scan_req);
 806  unlock:
 807         mutex_unlock(&local->mtx);
 808         return ret;
 809 }
 810
 811 /*
 812  * Only call this function when a scan can't be queued -- under RTNL.
 813  */
 814 void ieee80211_scan_cancel(struct ieee80211_local *local)
 815 {
 816         /*
 817          * We are canceling software scan, or deferred scan that was not
 818          * yet really started (see __ieee80211_start_scan ).
 819          *
 820          * Regarding hardware scan:
 821          * - we can not call  __ieee80211_scan_completed() as when
 822          *   SCAN_HW_SCANNING bit is set this function change
 823          *   local->hw_scan_req to operate on 5G band, what race with
 824          *   driver which can use local->hw_scan_req
 825          *
 826          * - we can not cancel scan_work since driver can schedule it
 827          *   by ieee80211_scan_completed(..., true) to finish scan
 828          *
 829          * Hence we only call the cancel_hw_scan() callback, but the low-level
 830          * driver is still responsible for calling ieee80211_scan_completed()
 831          * after the scan was completed/aborted.
 832          */
 833
 834         mutex_lock(&local->mtx);
 835         if (!local->scan_req)
 836                 goto out;
 837
 838         if (test_bit(SCAN_HW_SCANNING, &local->scanning)) {
 839                 if (local->ops->cancel_hw_scan)
 840                         drv_cancel_hw_scan(local, local->scan_sdata);
 841                 goto out;
 842         }
 843
 844         /*
 845          * If the work is currently running, it must be blocked on
 846          * the mutex, but we'll set scan_sdata = NULL and it'll
 847          * simply exit once it acquires the mutex.
 848          */
 849         cancel_delayed_work(&local->scan_work);
 850         /* and clean up */
 851         __ieee80211_scan_completed(&local->hw, true, false);
 852 out:
 853         mutex_unlock(&local->mtx);
 854 }
 855
 856 int ieee80211_request_sched_scan_start(struct ieee80211_sub_if_data *sdata,
 857                                        struct cfg80211_sched_scan_request *req)
 858 {
 859         struct ieee80211_local *local = sdata->local;
 860         int ret, i;
 861
 862         mutex_lock(&sdata->local->mtx);
 863
 864         if (local->sched_scanning) {
 865                 ret = -EBUSY;
 866                 goto out;
 867         }
 868
 869         if (!local->ops->sched_scan_start) {
 870                 ret = -ENOTSUPP;
 871                 goto out;
 872         }
 873
 874         for (i = 0; i < IEEE80211_NUM_BANDS; i++) {
 875                 local->sched_scan_ies.ie[i] = kzalloc(2 +
 876                                                       IEEE80211_MAX_SSID_LEN +
 877                                                       local->scan_ies_len +
 878                                                       req->ie_len,
 879                                                       GFP_KERNEL);
 880                 if (!local->sched_scan_ies.ie[i]) {
 881                         ret = -ENOMEM;
 882                         goto out_free;
 883                 }
 884
 885                 local->sched_scan_ies.len[i] =
 886                         ieee80211_build_preq_ies(local,
 887                                                  local->sched_scan_ies.ie[i],
 888                                                  req->ie, req->ie_len, i,
 889                                                  (u32) -1, 0);
 890         }
 891
 892         ret = drv_sched_scan_start(local, sdata, req,
 893                                    &local->sched_scan_ies);
 894         if (ret == 0) {
 895                 local->sched_scanning = true;
 896                 goto out;
 897         }
 898
 899 out_free:
 900         while (i > 0)
 901                 kfree(local->sched_scan_ies.ie[--i]);
 902 out:
 903         mutex_unlock(&sdata->local->mtx);
 904         return ret;
 905 }
 906
 907 int ieee80211_request_sched_scan_stop(struct ieee80211_sub_if_data *sdata)
 908 {
 909         struct ieee80211_local *local = sdata->local;
 910         int ret = 0, i;
 911
 912         mutex_lock(&sdata->local->mtx);
 913
 914         if (!local->ops->sched_scan_stop) {
 915                 ret = -ENOTSUPP;
 916                 goto out;
 917         }
 918
 919         if (local->sched_scanning) {
 920                 for (i = 0; i < IEEE80211_NUM_BANDS; i++)
 921                         kfree(local->sched_scan_ies.ie[i]);
 922
 923                 drv_sched_scan_stop(local, sdata);
 924                 local->sched_scanning = false;
 925         }
 926 out:
 927         mutex_unlock(&sdata->local->mtx);
 928
 929         return ret;
 930 }
 931
 932 void ieee80211_sched_scan_results(struct ieee80211_hw *hw)
 933 {
 934         struct ieee80211_local *local = hw_to_local(hw);
 935
 936         trace_api_sched_scan_results(local);
 937
 938         cfg80211_sched_scan_results(hw->wiphy);
 939 }
 940 EXPORT_SYMBOL(ieee80211_sched_scan_results);
 941
 942 void ieee80211_sched_scan_stopped_work(struct work_struct *work)
 943 {
 944         struct ieee80211_local *local =
 945                 container_of(work, struct ieee80211_local,
 946                              sched_scan_stopped_work);
 947         int i;
 948
 949         mutex_lock(&local->mtx);
 950
 951         if (!local->sched_scanning) {
 952                 mutex_unlock(&local->mtx);
 953                 return;
 954         }
 955
 956         for (i = 0; i < IEEE80211_NUM_BANDS; i++)
 957                 kfree(local->sched_scan_ies.ie[i]);
 958
 959         local->sched_scanning = false;
 960
 961         mutex_unlock(&local->mtx);
 962
 963         cfg80211_sched_scan_stopped(local->hw.wiphy);
 964 }
 965
 966 void ieee80211_sched_scan_stopped(struct ieee80211_hw *hw)
 967 {
 968         struct ieee80211_local *local = hw_to_local(hw);
 969
 970         trace_api_sched_scan_stopped(local);
 971
 972         ieee80211_queue_work(&local->hw, &local->sched_scan_stopped_work);
 973 }
 974 EXPORT_SYMBOL(ieee80211_sched_scan_stopped);