net/mac80211/scan.c

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