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/rtnetlink.h>
  17 #include <linux/pm_qos_params.h>
  18 #include <net/sch_generic.h>
  19 #include <linux/slab.h>
  20 #include <net/mac80211.h>
  21
  22 #include "ieee80211_i.h"
  23 #include "driver-ops.h"
  24 #include "mesh.h"
  25
  26 #define IEEE80211_PROBE_DELAY (HZ / 33)
  27 #define IEEE80211_CHANNEL_TIME (HZ / 33)
  28 #define IEEE80211_PASSIVE_CHANNEL_TIME (HZ / 8)
  29
  30 struct ieee80211_bss *
  31 ieee80211_rx_bss_get(struct ieee80211_local *local, u8 *bssid, int freq,
  32                      u8 *ssid, u8 ssid_len)
  33 {
  34         struct cfg80211_bss *cbss;
  35
  36         cbss = cfg80211_get_bss(local->hw.wiphy,
  37                                 ieee80211_get_channel(local->hw.wiphy, freq),
  38                                 bssid, ssid, ssid_len, 0, 0);
  39         if (!cbss)
  40                 return NULL;
  41         return (void *)cbss->priv;
  42 }
  43
  44 static void ieee80211_rx_bss_free(struct cfg80211_bss *cbss)
  45 {
  46         struct ieee80211_bss *bss = (void *)cbss->priv;
  47
  48         kfree(bss_mesh_id(bss));
  49         kfree(bss_mesh_cfg(bss));
  50 }
  51
  52 void ieee80211_rx_bss_put(struct ieee80211_local *local,
  53                           struct ieee80211_bss *bss)
  54 {
  55         if (!bss)
  56                 return;
  57         cfg80211_put_bss(container_of((void *)bss, struct cfg80211_bss, priv));
  58 }
  59
  60 static bool is_uapsd_supported(struct ieee802_11_elems *elems)
  61 {
  62         u8 qos_info;
  63
  64         if (elems->wmm_info && elems->wmm_info_len == 7
  65             && elems->wmm_info[5] == 1)
  66                 qos_info = elems->wmm_info[6];
  67         else if (elems->wmm_param && elems->wmm_param_len == 24
  68                  && elems->wmm_param[5] == 1)
  69                 qos_info = elems->wmm_param[6];
  70         else
  71                 /* no valid wmm information or parameter element found */
  72                 return false;
  73
  74         return qos_info & IEEE80211_WMM_IE_AP_QOSINFO_UAPSD;
  75 }
  76
  77 struct ieee80211_bss *
  78 ieee80211_bss_info_update(struct ieee80211_local *local,
  79                           struct ieee80211_rx_status *rx_status,
  80                           struct ieee80211_mgmt *mgmt,
  81                           size_t len,
  82                           struct ieee802_11_elems *elems,
  83                           struct ieee80211_channel *channel,
  84                           bool beacon)
  85 {
  86         struct cfg80211_bss *cbss;
  87         struct ieee80211_bss *bss;
  88         int clen, srlen;
  89         s32 signal = 0;
  90
  91         if (local->hw.flags & IEEE80211_HW_SIGNAL_DBM)
  92                 signal = rx_status->signal * 100;
  93         else if (local->hw.flags & IEEE80211_HW_SIGNAL_UNSPEC)
  94                 signal = (rx_status->signal * 100) / local->hw.max_signal;
  95
  96         cbss = cfg80211_inform_bss_frame(local->hw.wiphy, channel,
  97                                          mgmt, len, signal, GFP_ATOMIC);
  98
  99         if (!cbss)
 100                 return NULL;
 101
 102         cbss->free_priv = ieee80211_rx_bss_free;
 103         bss = (void *)cbss->priv;
 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                 bss->erp_value = elems->erp_info[0];
 108                 bss->has_erp_value = 1;
 109         }
 110
 111         if (elems->tim) {
 112                 struct ieee80211_tim_ie *tim_ie =
 113                         (struct ieee80211_tim_ie *)elems->tim;
 114                 bss->dtim_period = tim_ie->dtim_period;
 115         }
 116
 117         /* If the beacon had no TIM IE, or it was invalid, use 1 */
 118         if (beacon && !bss->dtim_period)
 119                 bss->dtim_period = 1;
 120
 121         /* replace old supported rates if we get new values */
 122         srlen = 0;
 123         if (elems->supp_rates) {
 124                 clen = IEEE80211_MAX_SUPP_RATES;
 125                 if (clen > elems->supp_rates_len)
 126                         clen = elems->supp_rates_len;
 127                 memcpy(bss->supp_rates, elems->supp_rates, clen);
 128                 srlen += clen;
 129         }
 130         if (elems->ext_supp_rates) {
 131                 clen = IEEE80211_MAX_SUPP_RATES - srlen;
 132                 if (clen > elems->ext_supp_rates_len)
 133                         clen = elems->ext_supp_rates_len;
 134                 memcpy(bss->supp_rates + srlen, elems->ext_supp_rates, clen);
 135                 srlen += clen;
 136         }
 137         if (srlen)
 138                 bss->supp_rates_len = srlen;
 139
 140         bss->wmm_used = elems->wmm_param || elems->wmm_info;
 141         bss->uapsd_supported = is_uapsd_supported(elems);
 142
 143         if (!beacon)
 144                 bss->last_probe_resp = jiffies;
 145
 146         return bss;
 147 }
 148
 149 ieee80211_rx_result
 150 ieee80211_scan_rx(struct ieee80211_sub_if_data *sdata, struct sk_buff *skb)
 151 {
 152         struct ieee80211_rx_status *rx_status = IEEE80211_SKB_RXCB(skb);
 153         struct ieee80211_mgmt *mgmt;
 154         struct ieee80211_bss *bss;
 155         u8 *elements;
 156         struct ieee80211_channel *channel;
 157         size_t baselen;
 158         int freq;
 159         __le16 fc;
 160         bool presp, beacon = false;
 161         struct ieee802_11_elems elems;
 162
 163         if (skb->len < 2)
 164                 return RX_DROP_UNUSABLE;
 165
 166         mgmt = (struct ieee80211_mgmt *) skb->data;
 167         fc = mgmt->frame_control;
 168
 169         if (ieee80211_is_ctl(fc))
 170                 return RX_CONTINUE;
 171
 172         if (skb->len < 24)
 173                 return RX_DROP_MONITOR;
 174
 175         presp = ieee80211_is_probe_resp(fc);
 176         if (presp) {
 177                 /* ignore ProbeResp to foreign address */
 178                 if (memcmp(mgmt->da, sdata->vif.addr, ETH_ALEN))
 179                         return RX_DROP_MONITOR;
 180
 181                 presp = true;
 182                 elements = mgmt->u.probe_resp.variable;
 183                 baselen = offsetof(struct ieee80211_mgmt, u.probe_resp.variable);
 184         } else {
 185                 beacon = ieee80211_is_beacon(fc);
 186                 baselen = offsetof(struct ieee80211_mgmt, u.beacon.variable);
 187                 elements = mgmt->u.beacon.variable;
 188         }
 189
 190         if (!presp && !beacon)
 191                 return RX_CONTINUE;
 192
 193         if (baselen > skb->len)
 194                 return RX_DROP_MONITOR;
 195
 196         ieee802_11_parse_elems(elements, skb->len - baselen, &elems);
 197
 198         if (elems.ds_params && elems.ds_params_len == 1)
 199                 freq = ieee80211_channel_to_frequency(elems.ds_params[0]);
 200         else
 201                 freq = rx_status->freq;
 202
 203         channel = ieee80211_get_channel(sdata->local->hw.wiphy, freq);
 204
 205         if (!channel || channel->flags & IEEE80211_CHAN_DISABLED)
 206                 return RX_DROP_MONITOR;
 207
 208         bss = ieee80211_bss_info_update(sdata->local, rx_status,
 209                                         mgmt, skb->len, &elems,
 210                                         channel, beacon);
 211         if (bss)
 212                 ieee80211_rx_bss_put(sdata->local, bss);
 213
 214         dev_kfree_skb(skb);
 215         return RX_QUEUED;
 216 }
 217
 218 /* return false if no more work */
 219 static bool ieee80211_prep_hw_scan(struct ieee80211_local *local)
 220 {
 221         struct cfg80211_scan_request *req = local->scan_req;
 222         enum ieee80211_band band;
 223         int i, ielen, n_chans;
 224
 225         do {
 226                 if (local->hw_scan_band == IEEE80211_NUM_BANDS)
 227                         return false;
 228
 229                 band = local->hw_scan_band;
 230                 n_chans = 0;
 231                 for (i = 0; i < req->n_channels; i++) {
 232                         if (req->channels[i]->band == band) {
 233                                 local->hw_scan_req->channels[n_chans] =
 234                                                         req->channels[i];
 235                                 n_chans++;
 236                         }
 237                 }
 238
 239                 local->hw_scan_band++;
 240         } while (!n_chans);
 241
 242         local->hw_scan_req->n_channels = n_chans;
 243
 244         ielen = ieee80211_build_preq_ies(local, (u8 *)local->hw_scan_req->ie,
 245                                          req->ie, req->ie_len, band);
 246         local->hw_scan_req->ie_len = ielen;
 247
 248         return true;
 249 }
 250
 251 void ieee80211_scan_completed(struct ieee80211_hw *hw, bool aborted)
 252 {
 253         struct ieee80211_local *local = hw_to_local(hw);
 254         bool was_hw_scan;
 255
 256         trace_api_scan_completed(local, aborted);
 257
 258         mutex_lock(&local->scan_mtx);
 259
 260         /*
 261          * It's ok to abort a not-yet-running scan (that
 262          * we have one at all will be verified by checking
 263          * local->scan_req next), but not to complete it
 264          * successfully.
 265          */
 266         if (WARN_ON(!local->scanning && !aborted))
 267                 aborted = true;
 268
 269         if (WARN_ON(!local->scan_req)) {
 270                 mutex_unlock(&local->scan_mtx);
 271                 return;
 272         }
 273
 274         was_hw_scan = test_bit(SCAN_HW_SCANNING, &local->scanning);
 275         if (was_hw_scan && !aborted && ieee80211_prep_hw_scan(local)) {
 276                 ieee80211_queue_delayed_work(&local->hw,
 277                                              &local->scan_work, 0);
 278                 mutex_unlock(&local->scan_mtx);
 279                 return;
 280         }
 281
 282         kfree(local->hw_scan_req);
 283         local->hw_scan_req = NULL;
 284
 285         if (local->scan_req != local->int_scan_req)
 286                 cfg80211_scan_done(local->scan_req, aborted);
 287         local->scan_req = NULL;
 288         local->scan_sdata = NULL;
 289
 290         local->scanning = 0;
 291         local->scan_channel = NULL;
 292
 293         /* we only have to protect scan_req and hw/sw scan */
 294         mutex_unlock(&local->scan_mtx);
 295
 296         ieee80211_hw_config(local, IEEE80211_CONF_CHANGE_CHANNEL);
 297         if (was_hw_scan)
 298                 goto done;
 299
 300         ieee80211_configure_filter(local);
 301
 302         drv_sw_scan_complete(local);
 303
 304         ieee80211_offchannel_return(local, true);
 305
 306  done:
 307         ieee80211_recalc_idle(local);
 308         ieee80211_mlme_notify_scan_completed(local);
 309         ieee80211_ibss_notify_scan_completed(local);
 310         ieee80211_mesh_notify_scan_completed(local);
 311         ieee80211_queue_work(&local->hw, &local->work_work);
 312 }
 313 EXPORT_SYMBOL(ieee80211_scan_completed);
 314
 315 static int ieee80211_start_sw_scan(struct ieee80211_local *local)
 316 {
 317         /*
 318          * Hardware/driver doesn't support hw_scan, so use software
 319          * scanning instead. First send a nullfunc frame with power save
 320          * bit on so that AP will buffer the frames for us while we are not
 321          * listening, then send probe requests to each channel and wait for
 322          * the responses. After all channels are scanned, tune back to the
 323          * original channel and send a nullfunc frame with power save bit
 324          * off to trigger the AP to send us all the buffered frames.
 325          *
 326          * Note that while local->sw_scanning is true everything else but
 327          * nullfunc frames and probe requests will be dropped in
 328          * ieee80211_tx_h_check_assoc().
 329          */
 330         drv_sw_scan_start(local);
 331
 332         ieee80211_offchannel_stop_beaconing(local);
 333
 334         local->leave_oper_channel_time = 0;
 335         local->next_scan_state = SCAN_DECISION;
 336         local->scan_channel_idx = 0;
 337
 338         drv_flush(local, false);
 339
 340         ieee80211_configure_filter(local);
 341
 342         ieee80211_queue_delayed_work(&local->hw,
 343                                      &local->scan_work,
 344                                      IEEE80211_CHANNEL_TIME);
 345
 346         return 0;
 347 }
 348
 349
 350 static int __ieee80211_start_scan(struct ieee80211_sub_if_data *sdata,
 351                                   struct cfg80211_scan_request *req)
 352 {
 353         struct ieee80211_local *local = sdata->local;
 354         int rc;
 355
 356         if (local->scan_req)
 357                 return -EBUSY;
 358
 359         if (!list_empty(&local->work_list)) {
 360                 /* wait for the work to finish/time out */
 361                 local->scan_req = req;
 362                 local->scan_sdata = sdata;
 363                 return 0;
 364         }
 365
 366         if (local->ops->hw_scan) {
 367                 u8 *ies;
 368
 369                 local->hw_scan_req = kmalloc(
 370                                 sizeof(*local->hw_scan_req) +
 371                                 req->n_channels * sizeof(req->channels[0]) +
 372                                 2 + IEEE80211_MAX_SSID_LEN + local->scan_ies_len +
 373                                 req->ie_len, GFP_KERNEL);
 374                 if (!local->hw_scan_req)
 375                         return -ENOMEM;
 376
 377                 local->hw_scan_req->ssids = req->ssids;
 378                 local->hw_scan_req->n_ssids = req->n_ssids;
 379                 ies = (u8 *)local->hw_scan_req +
 380                         sizeof(*local->hw_scan_req) +
 381                         req->n_channels * sizeof(req->channels[0]);
 382                 local->hw_scan_req->ie = ies;
 383
 384                 local->hw_scan_band = 0;
 385
 386                 /*
 387                  * After allocating local->hw_scan_req, we must
 388                  * go through until ieee80211_prep_hw_scan(), so
 389                  * anything that might be changed here and leave
 390                  * this function early must not go after this
 391                  * allocation.
 392                  */
 393         }
 394
 395         local->scan_req = req;
 396         local->scan_sdata = sdata;
 397
 398         if (local->ops->hw_scan)
 399                 __set_bit(SCAN_HW_SCANNING, &local->scanning);
 400         else
 401                 __set_bit(SCAN_SW_SCANNING, &local->scanning);
 402
 403         ieee80211_recalc_idle(local);
 404
 405         if (local->ops->hw_scan) {
 406                 WARN_ON(!ieee80211_prep_hw_scan(local));
 407                 rc = drv_hw_scan(local, sdata, local->hw_scan_req);
 408         } else
 409                 rc = ieee80211_start_sw_scan(local);
 410
 411         if (rc) {
 412                 kfree(local->hw_scan_req);
 413                 local->hw_scan_req = NULL;
 414                 local->scanning = 0;
 415
 416                 ieee80211_recalc_idle(local);
 417
 418                 local->scan_req = NULL;
 419                 local->scan_sdata = NULL;
 420         }
 421
 422         return rc;
 423 }
 424
 425 static unsigned long
 426 ieee80211_scan_get_channel_time(struct ieee80211_channel *chan)
 427 {
 428         /*
 429          * TODO: channel switching also consumes quite some time,
 430          * add that delay as well to get a better estimation
 431          */
 432         if (chan->flags & IEEE80211_CHAN_PASSIVE_SCAN)
 433                 return IEEE80211_PASSIVE_CHANNEL_TIME;
 434         return IEEE80211_PROBE_DELAY + IEEE80211_CHANNEL_TIME;
 435 }
 436
 437 static int ieee80211_scan_state_decision(struct ieee80211_local *local,
 438                                          unsigned long *next_delay)
 439 {
 440         bool associated = false;
 441         bool tx_empty = true;
 442         bool bad_latency;
 443         bool listen_int_exceeded;
 444         unsigned long min_beacon_int = 0;
 445         struct ieee80211_sub_if_data *sdata;
 446         struct ieee80211_channel *next_chan;
 447
 448         /* if no more bands/channels left, complete scan and advance to the idle state */
 449         if (local->scan_channel_idx >= local->scan_req->n_channels) {
 450                 ieee80211_scan_completed(&local->hw, false);
 451                 return 1;
 452         }
 453
 454         /*
 455          * check if at least one STA interface is associated,
 456          * check if at least one STA interface has pending tx frames
 457          * and grab the lowest used beacon interval
 458          */
 459         mutex_lock(&local->iflist_mtx);
 460         list_for_each_entry(sdata, &local->interfaces, list) {
 461                 if (!ieee80211_sdata_running(sdata))
 462                         continue;
 463
 464                 if (sdata->vif.type == NL80211_IFTYPE_STATION) {
 465                         if (sdata->u.mgd.associated) {
 466                                 associated = true;
 467
 468                                 if (sdata->vif.bss_conf.beacon_int <
 469                                     min_beacon_int || min_beacon_int == 0)
 470                                         min_beacon_int =
 471                                                 sdata->vif.bss_conf.beacon_int;
 472
 473                                 if (!qdisc_all_tx_empty(sdata->dev)) {
 474                                         tx_empty = false;
 475                                         break;
 476                                 }
 477                         }
 478                 }
 479         }
 480         mutex_unlock(&local->iflist_mtx);
 481
 482         if (local->scan_channel) {
 483                 /*
 484                  * we're currently scanning a different channel, let's
 485                  * see if we can scan another channel without interfering
 486                  * with the current traffic situation.
 487                  *
 488                  * Since we don't know if the AP has pending frames for us
 489                  * we can only check for our tx queues and use the current
 490                  * pm_qos requirements for rx. Hence, if no tx traffic occurs
 491                  * at all we will scan as many channels in a row as the pm_qos
 492                  * latency allows us to. Additionally we also check for the
 493                  * currently negotiated listen interval to prevent losing
 494                  * frames unnecessarily.
 495                  *
 496                  * Otherwise switch back to the operating channel.
 497                  */
 498                 next_chan = local->scan_req->channels[local->scan_channel_idx];
 499
 500                 bad_latency = time_after(jiffies +
 501                                 ieee80211_scan_get_channel_time(next_chan),
 502                                 local->leave_oper_channel_time +
 503                                 usecs_to_jiffies(pm_qos_request(PM_QOS_NETWORK_LATENCY)));
 504
 505                 listen_int_exceeded = time_after(jiffies +
 506                                 ieee80211_scan_get_channel_time(next_chan),
 507                                 local->leave_oper_channel_time +
 508                                 usecs_to_jiffies(min_beacon_int * 1024) *
 509                                 local->hw.conf.listen_interval);
 510
 511                 if (associated && ( !tx_empty || bad_latency ||
 512                     listen_int_exceeded))
 513                         local->next_scan_state = SCAN_ENTER_OPER_CHANNEL;
 514                 else
 515                         local->next_scan_state = SCAN_SET_CHANNEL;
 516         } else {
 517                 /*
 518                  * we're on the operating channel currently, let's
 519                  * leave that channel now to scan another one
 520                  */
 521                 local->next_scan_state = SCAN_LEAVE_OPER_CHANNEL;
 522         }
 523
 524         *next_delay = 0;
 525         return 0;
 526 }
 527
 528 static void ieee80211_scan_state_leave_oper_channel(struct ieee80211_local *local,
 529                                                     unsigned long *next_delay)
 530 {
 531         ieee80211_offchannel_stop_station(local);
 532
 533         __set_bit(SCAN_OFF_CHANNEL, &local->scanning);
 534
 535         /*
 536          * What if the nullfunc frames didn't arrive?
 537          */
 538         drv_flush(local, false);
 539         if (local->ops->flush)
 540                 *next_delay = 0;
 541         else
 542                 *next_delay = HZ / 10;
 543
 544         /* remember when we left the operating channel */
 545         local->leave_oper_channel_time = jiffies;
 546
 547         /* advance to the next channel to be scanned */
 548         local->next_scan_state = SCAN_SET_CHANNEL;
 549 }
 550
 551 static void ieee80211_scan_state_enter_oper_channel(struct ieee80211_local *local,
 552                                                     unsigned long *next_delay)
 553 {
 554         /* switch back to the operating channel */
 555         local->scan_channel = NULL;
 556         ieee80211_hw_config(local, IEEE80211_CONF_CHANGE_CHANNEL);
 557
 558         /*
 559          * Only re-enable station mode interface now; beaconing will be
 560          * re-enabled once the full scan has been completed.
 561          */
 562         ieee80211_offchannel_return(local, false);
 563
 564         __clear_bit(SCAN_OFF_CHANNEL, &local->scanning);
 565
 566         *next_delay = HZ / 5;
 567         local->next_scan_state = SCAN_DECISION;
 568 }
 569
 570 static void ieee80211_scan_state_set_channel(struct ieee80211_local *local,
 571                                              unsigned long *next_delay)
 572 {
 573         int skip;
 574         struct ieee80211_channel *chan;
 575
 576         skip = 0;
 577         chan = local->scan_req->channels[local->scan_channel_idx];
 578
 579         local->scan_channel = chan;
 580         if (ieee80211_hw_config(local, IEEE80211_CONF_CHANGE_CHANNEL))
 581                 skip = 1;
 582
 583         /* advance state machine to next channel/band */
 584         local->scan_channel_idx++;
 585
 586         if (skip) {
 587                 /* if we skip this channel return to the decision state */
 588                 local->next_scan_state = SCAN_DECISION;
 589                 return;
 590         }
 591
 592         /*
 593          * Probe delay is used to update the NAV, cf. 11.1.3.2.2
 594          * (which unfortunately doesn't say _why_ step a) is done,
 595          * but it waits for the probe delay or until a frame is
 596          * received - and the received frame would update the NAV).
 597          * For now, we do not support waiting until a frame is
 598          * received.
 599          *
 600          * In any case, it is not necessary for a passive scan.
 601          */
 602         if (chan->flags & IEEE80211_CHAN_PASSIVE_SCAN ||
 603             !local->scan_req->n_ssids) {
 604                 *next_delay = IEEE80211_PASSIVE_CHANNEL_TIME;
 605                 local->next_scan_state = SCAN_DECISION;
 606                 return;
 607         }
 608
 609         /* active scan, send probes */
 610         *next_delay = IEEE80211_PROBE_DELAY;
 611         local->next_scan_state = SCAN_SEND_PROBE;
 612 }
 613
 614 static void ieee80211_scan_state_send_probe(struct ieee80211_local *local,
 615                                             unsigned long *next_delay)
 616 {
 617         int i;
 618         struct ieee80211_sub_if_data *sdata = local->scan_sdata;
 619
 620         for (i = 0; i < local->scan_req->n_ssids; i++)
 621                 ieee80211_send_probe_req(
 622                         sdata, NULL,
 623                         local->scan_req->ssids[i].ssid,
 624                         local->scan_req->ssids[i].ssid_len,
 625                         local->scan_req->ie, local->scan_req->ie_len);
 626
 627         /*
 628          * After sending probe requests, wait for probe responses
 629          * on the channel.
 630          */
 631         *next_delay = IEEE80211_CHANNEL_TIME;
 632         local->next_scan_state = SCAN_DECISION;
 633 }
 634
 635 void ieee80211_scan_work(struct work_struct *work)
 636 {
 637         struct ieee80211_local *local =
 638                 container_of(work, struct ieee80211_local, scan_work.work);
 639         struct ieee80211_sub_if_data *sdata = local->scan_sdata;
 640         unsigned long next_delay = 0;
 641
 642         mutex_lock(&local->scan_mtx);
 643         if (!sdata || !local->scan_req) {
 644                 mutex_unlock(&local->scan_mtx);
 645                 return;
 646         }
 647
 648         if (local->hw_scan_req) {
 649                 int rc = drv_hw_scan(local, sdata, local->hw_scan_req);
 650                 mutex_unlock(&local->scan_mtx);
 651                 if (rc)
 652                         ieee80211_scan_completed(&local->hw, true);
 653                 return;
 654         }
 655
 656         if (local->scan_req && !local->scanning) {
 657                 struct cfg80211_scan_request *req = local->scan_req;
 658                 int rc;
 659
 660                 local->scan_req = NULL;
 661                 local->scan_sdata = NULL;
 662
 663                 rc = __ieee80211_start_scan(sdata, req);
 664                 mutex_unlock(&local->scan_mtx);
 665
 666                 if (rc)
 667                         ieee80211_scan_completed(&local->hw, true);
 668                 return;
 669         }
 670
 671         mutex_unlock(&local->scan_mtx);
 672
 673         /*
 674          * Avoid re-scheduling when the sdata is going away.
 675          */
 676         if (!ieee80211_sdata_running(sdata)) {
 677                 ieee80211_scan_completed(&local->hw, true);
 678                 return;
 679         }
 680
 681         /*
 682          * as long as no delay is required advance immediately
 683          * without scheduling a new work
 684          */
 685         do {
 686                 switch (local->next_scan_state) {
 687                 case SCAN_DECISION:
 688                         if (ieee80211_scan_state_decision(local, &next_delay))
 689                                 return;
 690                         break;
 691                 case SCAN_SET_CHANNEL:
 692                         ieee80211_scan_state_set_channel(local, &next_delay);
 693                         break;
 694                 case SCAN_SEND_PROBE:
 695                         ieee80211_scan_state_send_probe(local, &next_delay);
 696                         break;
 697                 case SCAN_LEAVE_OPER_CHANNEL:
 698                         ieee80211_scan_state_leave_oper_channel(local, &next_delay);
 699                         break;
 700                 case SCAN_ENTER_OPER_CHANNEL:
 701                         ieee80211_scan_state_enter_oper_channel(local, &next_delay);
 702                         break;
 703                 }
 704         } while (next_delay == 0);
 705
 706         ieee80211_queue_delayed_work(&local->hw, &local->scan_work, next_delay);
 707 }
 708
 709 int ieee80211_request_scan(struct ieee80211_sub_if_data *sdata,
 710                            struct cfg80211_scan_request *req)
 711 {
 712         int res;
 713
 714         mutex_lock(&sdata->local->scan_mtx);
 715         res = __ieee80211_start_scan(sdata, req);
 716         mutex_unlock(&sdata->local->scan_mtx);
 717
 718         return res;
 719 }
 720
 721 int ieee80211_request_internal_scan(struct ieee80211_sub_if_data *sdata,
 722                                     const u8 *ssid, u8 ssid_len,
 723                                     struct ieee80211_channel *chan)
 724 {
 725         struct ieee80211_local *local = sdata->local;
 726         int ret = -EBUSY;
 727         enum ieee80211_band band;
 728
 729         mutex_lock(&local->scan_mtx);
 730
 731         /* busy scanning */
 732         if (local->scan_req)
 733                 goto unlock;
 734
 735         /* fill internal scan request */
 736         if (!chan) {
 737                 int i, nchan = 0;
 738
 739                 for (band = 0; band < IEEE80211_NUM_BANDS; band++) {
 740                         if (!local->hw.wiphy->bands[band])
 741                                 continue;
 742                         for (i = 0;
 743                              i < local->hw.wiphy->bands[band]->n_channels;
 744                              i++) {
 745                                 local->int_scan_req->channels[nchan] =
 746                                     &local->hw.wiphy->bands[band]->channels[i];
 747                                 nchan++;
 748                         }
 749                 }
 750
 751                 local->int_scan_req->n_channels = nchan;
 752         } else {
 753                 local->int_scan_req->channels[0] = chan;
 754                 local->int_scan_req->n_channels = 1;
 755         }
 756
 757         local->int_scan_req->ssids = &local->scan_ssid;
 758         local->int_scan_req->n_ssids = 1;
 759         memcpy(local->int_scan_req->ssids[0].ssid, ssid, IEEE80211_MAX_SSID_LEN);
 760         local->int_scan_req->ssids[0].ssid_len = ssid_len;
 761
 762         ret = __ieee80211_start_scan(sdata, sdata->local->int_scan_req);
 763  unlock:
 764         mutex_unlock(&local->scan_mtx);
 765         return ret;
 766 }
 767
 768 void ieee80211_scan_cancel(struct ieee80211_local *local)
 769 {
 770         bool abortscan;
 771
 772         cancel_delayed_work_sync(&local->scan_work);
 773
 774         /*
 775          * Only call this function when a scan can't be
 776          * queued -- mostly at suspend under RTNL.
 777          */
 778         mutex_lock(&local->scan_mtx);
 779         abortscan = test_bit(SCAN_SW_SCANNING, &local->scanning) ||
 780                     (!local->scanning && local->scan_req);
 781         mutex_unlock(&local->scan_mtx);
 782
 783         if (abortscan)
 784                 ieee80211_scan_completed(&local->hw, true);
 785 }