1 /* 2 * Scanning implementation 3 * 4 * Copyright 2003, Jouni Malinen <jkmaline@cc.hut.fi> 5 * Copyright 2004, Instant802 Networks, Inc. 6 * Copyright 2005, Devicescape Software, Inc. 7 * Copyright 2006-2007 Jiri Benc <jbenc@suse.cz> 8 * Copyright 2007, Michael Wu <flamingice@sourmilk.net> 9 * 10 * This program is free software; you can redistribute it and/or modify 11 * it under the terms of the GNU General Public License version 2 as 12 * published by the Free Software Foundation. 13 */ 14 15 #include <linux/if_arp.h> 16 #include <linux/etherdevice.h> 17 #include <linux/rtnetlink.h> 18 #include <linux/pm_qos.h> 19 #include <net/sch_generic.h> 20 #include <linux/slab.h> 21 #include <linux/export.h> 22 #include <net/mac80211.h> 23 24 #include "ieee80211_i.h" 25 #include "driver-ops.h" 26 #include "mesh.h" 27 28 #define IEEE80211_PROBE_DELAY (HZ / 33) 29 #define IEEE80211_CHANNEL_TIME (HZ / 33) 30 #define IEEE80211_PASSIVE_CHANNEL_TIME (HZ / 8) 31 32 static void ieee80211_rx_bss_free(struct cfg80211_bss *cbss) 33 { 34 struct ieee80211_bss *bss = (void *)cbss->priv; 35 36 kfree(bss_mesh_id(bss)); 37 kfree(bss_mesh_cfg(bss)); 38 } 39 40 void ieee80211_rx_bss_put(struct ieee80211_local *local, 41 struct ieee80211_bss *bss) 42 { 43 if (!bss) 44 return; 45 cfg80211_put_bss(container_of((void *)bss, struct cfg80211_bss, priv)); 46 } 47 48 static bool is_uapsd_supported(struct ieee802_11_elems *elems) 49 { 50 u8 qos_info; 51 52 if (elems->wmm_info && elems->wmm_info_len == 7 53 && elems->wmm_info[5] == 1) 54 qos_info = elems->wmm_info[6]; 55 else if (elems->wmm_param && elems->wmm_param_len == 24 56 && elems->wmm_param[5] == 1) 57 qos_info = elems->wmm_param[6]; 58 else 59 /* no valid wmm information or parameter element found */ 60 return false; 61 62 return qos_info & IEEE80211_WMM_IE_AP_QOSINFO_UAPSD; 63 } 64 65 struct ieee80211_bss * 66 ieee80211_bss_info_update(struct ieee80211_local *local, 67 struct ieee80211_rx_status *rx_status, 68 struct ieee80211_mgmt *mgmt, 69 size_t len, 70 struct ieee802_11_elems *elems, 71 struct ieee80211_channel *channel, 72 bool beacon) 73 { 74 struct cfg80211_bss *cbss; 75 struct ieee80211_bss *bss; 76 int clen, srlen; 77 s32 signal = 0; 78 79 if (local->hw.flags & IEEE80211_HW_SIGNAL_DBM) 80 signal = rx_status->signal * 100; 81 else if (local->hw.flags & IEEE80211_HW_SIGNAL_UNSPEC) 82 signal = (rx_status->signal * 100) / local->hw.max_signal; 83 84 cbss = cfg80211_inform_bss_frame(local->hw.wiphy, channel, 85 mgmt, len, signal, GFP_ATOMIC); 86 if (!cbss) 87 return NULL; 88 89 cbss->free_priv = ieee80211_rx_bss_free; 90 bss = (void *)cbss->priv; 91 92 bss->device_ts = rx_status->device_timestamp; 93 94 if (elems->parse_error) { 95 if (beacon) 96 bss->corrupt_data |= IEEE80211_BSS_CORRUPT_BEACON; 97 else 98 bss->corrupt_data |= IEEE80211_BSS_CORRUPT_PROBE_RESP; 99 } else { 100 if (beacon) 101 bss->corrupt_data &= ~IEEE80211_BSS_CORRUPT_BEACON; 102 else 103 bss->corrupt_data &= ~IEEE80211_BSS_CORRUPT_PROBE_RESP; 104 } 105 106 /* save the ERP value so that it is available at association time */ 107 if (elems->erp_info && elems->erp_info_len >= 1 && 108 (!elems->parse_error || 109 !(bss->valid_data & IEEE80211_BSS_VALID_ERP))) { 110 bss->erp_value = elems->erp_info[0]; 111 bss->has_erp_value = true; 112 if (!elems->parse_error) 113 bss->valid_data |= IEEE80211_BSS_VALID_ERP; 114 } 115 116 if (elems->tim && (!elems->parse_error || 117 !(bss->valid_data & IEEE80211_BSS_VALID_DTIM))) { 118 struct ieee80211_tim_ie *tim_ie = elems->tim; 119 bss->dtim_period = tim_ie->dtim_period; 120 if (!elems->parse_error) 121 bss->valid_data |= IEEE80211_BSS_VALID_DTIM; 122 } 123 124 /* If the beacon had no TIM IE, or it was invalid, use 1 */ 125 if (beacon && !bss->dtim_period) 126 bss->dtim_period = 1; 127 128 /* replace old supported rates if we get new values */ 129 if (!elems->parse_error || 130 !(bss->valid_data & IEEE80211_BSS_VALID_RATES)) { 131 srlen = 0; 132 if (elems->supp_rates) { 133 clen = IEEE80211_MAX_SUPP_RATES; 134 if (clen > elems->supp_rates_len) 135 clen = elems->supp_rates_len; 136 memcpy(bss->supp_rates, elems->supp_rates, clen); 137 srlen += clen; 138 } 139 if (elems->ext_supp_rates) { 140 clen = IEEE80211_MAX_SUPP_RATES - srlen; 141 if (clen > elems->ext_supp_rates_len) 142 clen = elems->ext_supp_rates_len; 143 memcpy(bss->supp_rates + srlen, elems->ext_supp_rates, 144 clen); 145 srlen += clen; 146 } 147 if (srlen) { 148 bss->supp_rates_len = srlen; 149 if (!elems->parse_error) 150 bss->valid_data |= IEEE80211_BSS_VALID_RATES; 151 } 152 } 153 154 if (!elems->parse_error || 155 !(bss->valid_data & IEEE80211_BSS_VALID_WMM)) { 156 bss->wmm_used = elems->wmm_param || elems->wmm_info; 157 bss->uapsd_supported = is_uapsd_supported(elems); 158 if (!elems->parse_error) 159 bss->valid_data |= IEEE80211_BSS_VALID_WMM; 160 } 161 162 if (!beacon) 163 bss->last_probe_resp = jiffies; 164 165 return bss; 166 } 167 168 void ieee80211_scan_rx(struct ieee80211_local *local, struct sk_buff *skb) 169 { 170 struct ieee80211_rx_status *rx_status = IEEE80211_SKB_RXCB(skb); 171 struct ieee80211_sub_if_data *sdata1, *sdata2; 172 struct ieee80211_mgmt *mgmt = (void *)skb->data; 173 struct ieee80211_bss *bss; 174 u8 *elements; 175 struct ieee80211_channel *channel; 176 size_t baselen; 177 bool beacon; 178 struct ieee802_11_elems elems; 179 180 if (skb->len < 24 || 181 (!ieee80211_is_probe_resp(mgmt->frame_control) && 182 !ieee80211_is_beacon(mgmt->frame_control))) 183 return; 184 185 sdata1 = rcu_dereference(local->scan_sdata); 186 sdata2 = rcu_dereference(local->sched_scan_sdata); 187 188 if (likely(!sdata1 && !sdata2)) 189 return; 190 191 if (ieee80211_is_probe_resp(mgmt->frame_control)) { 192 /* ignore ProbeResp to foreign address */ 193 if ((!sdata1 || !ether_addr_equal(mgmt->da, sdata1->vif.addr)) && 194 (!sdata2 || !ether_addr_equal(mgmt->da, sdata2->vif.addr))) 195 return; 196 197 elements = mgmt->u.probe_resp.variable; 198 baselen = offsetof(struct ieee80211_mgmt, u.probe_resp.variable); 199 beacon = false; 200 } else { 201 baselen = offsetof(struct ieee80211_mgmt, u.beacon.variable); 202 elements = mgmt->u.beacon.variable; 203 beacon = true; 204 } 205 206 if (baselen > skb->len) 207 return; 208 209 ieee802_11_parse_elems(elements, skb->len - baselen, &elems); 210 211 channel = ieee80211_get_channel(local->hw.wiphy, rx_status->freq); 212 213 if (!channel || channel->flags & IEEE80211_CHAN_DISABLED) 214 return; 215 216 bss = ieee80211_bss_info_update(local, rx_status, 217 mgmt, skb->len, &elems, 218 channel, beacon); 219 if (bss) 220 ieee80211_rx_bss_put(local, bss); 221 } 222 223 /* return false if no more work */ 224 static bool ieee80211_prep_hw_scan(struct ieee80211_local *local) 225 { 226 struct cfg80211_scan_request *req = local->scan_req; 227 enum ieee80211_band band; 228 int i, ielen, n_chans; 229 230 do { 231 if (local->hw_scan_band == IEEE80211_NUM_BANDS) 232 return false; 233 234 band = local->hw_scan_band; 235 n_chans = 0; 236 for (i = 0; i < req->n_channels; i++) { 237 if (req->channels[i]->band == band) { 238 local->hw_scan_req->channels[n_chans] = 239 req->channels[i]; 240 n_chans++; 241 } 242 } 243 244 local->hw_scan_band++; 245 } while (!n_chans); 246 247 local->hw_scan_req->n_channels = n_chans; 248 249 ielen = ieee80211_build_preq_ies(local, (u8 *)local->hw_scan_req->ie, 250 local->hw_scan_ies_bufsize, 251 req->ie, req->ie_len, band, 252 req->rates[band], 0); 253 local->hw_scan_req->ie_len = ielen; 254 local->hw_scan_req->no_cck = req->no_cck; 255 256 return true; 257 } 258 259 static void __ieee80211_scan_completed(struct ieee80211_hw *hw, bool aborted, 260 bool was_hw_scan) 261 { 262 struct ieee80211_local *local = hw_to_local(hw); 263 264 lockdep_assert_held(&local->mtx); 265 266 /* 267 * It's ok to abort a not-yet-running scan (that 268 * we have one at all will be verified by checking 269 * local->scan_req next), but not to complete it 270 * successfully. 271 */ 272 if (WARN_ON(!local->scanning && !aborted)) 273 aborted = true; 274 275 if (WARN_ON(!local->scan_req)) 276 return; 277 278 if (was_hw_scan && !aborted && ieee80211_prep_hw_scan(local)) { 279 int rc; 280 281 rc = drv_hw_scan(local, 282 rcu_dereference_protected(local->scan_sdata, 283 lockdep_is_held(&local->mtx)), 284 local->hw_scan_req); 285 286 if (rc == 0) 287 return; 288 } 289 290 kfree(local->hw_scan_req); 291 local->hw_scan_req = NULL; 292 293 if (local->scan_req != local->int_scan_req) 294 cfg80211_scan_done(local->scan_req, aborted); 295 local->scan_req = NULL; 296 rcu_assign_pointer(local->scan_sdata, NULL); 297 298 local->scanning = 0; 299 local->scan_channel = NULL; 300 301 /* Set power back to normal operating levels. */ 302 ieee80211_hw_config(local, 0); 303 304 if (!was_hw_scan) { 305 ieee80211_configure_filter(local); 306 drv_sw_scan_complete(local); 307 ieee80211_offchannel_return(local, true); 308 } 309 310 ieee80211_recalc_idle(local); 311 312 ieee80211_mlme_notify_scan_completed(local); 313 ieee80211_ibss_notify_scan_completed(local); 314 ieee80211_mesh_notify_scan_completed(local); 315 ieee80211_start_next_roc(local); 316 } 317 318 void ieee80211_scan_completed(struct ieee80211_hw *hw, bool aborted) 319 { 320 struct ieee80211_local *local = hw_to_local(hw); 321 322 trace_api_scan_completed(local, aborted); 323 324 set_bit(SCAN_COMPLETED, &local->scanning); 325 if (aborted) 326 set_bit(SCAN_ABORTED, &local->scanning); 327 ieee80211_queue_delayed_work(&local->hw, &local->scan_work, 0); 328 } 329 EXPORT_SYMBOL(ieee80211_scan_completed); 330 331 static int ieee80211_start_sw_scan(struct ieee80211_local *local) 332 { 333 /* Software scan is not supported in multi-channel cases */ 334 if (local->use_chanctx) 335 return -EOPNOTSUPP; 336 337 /* 338 * Hardware/driver doesn't support hw_scan, so use software 339 * scanning instead. First send a nullfunc frame with power save 340 * bit on so that AP will buffer the frames for us while we are not 341 * listening, then send probe requests to each channel and wait for 342 * the responses. After all channels are scanned, tune back to the 343 * original channel and send a nullfunc frame with power save bit 344 * off to trigger the AP to send us all the buffered frames. 345 * 346 * Note that while local->sw_scanning is true everything else but 347 * nullfunc frames and probe requests will be dropped in 348 * ieee80211_tx_h_check_assoc(). 349 */ 350 drv_sw_scan_start(local); 351 352 local->leave_oper_channel_time = jiffies; 353 local->next_scan_state = SCAN_DECISION; 354 local->scan_channel_idx = 0; 355 356 ieee80211_offchannel_stop_vifs(local, true); 357 358 ieee80211_configure_filter(local); 359 360 /* We need to set power level at maximum rate for scanning. */ 361 ieee80211_hw_config(local, 0); 362 363 ieee80211_queue_delayed_work(&local->hw, 364 &local->scan_work, 0); 365 366 return 0; 367 } 368 369 static bool ieee80211_can_scan(struct ieee80211_local *local, 370 struct ieee80211_sub_if_data *sdata) 371 { 372 if (!list_empty(&local->roc_list)) 373 return false; 374 375 if (sdata->vif.type == NL80211_IFTYPE_STATION && 376 sdata->u.mgd.flags & (IEEE80211_STA_BEACON_POLL | 377 IEEE80211_STA_CONNECTION_POLL)) 378 return false; 379 380 return true; 381 } 382 383 void ieee80211_run_deferred_scan(struct ieee80211_local *local) 384 { 385 lockdep_assert_held(&local->mtx); 386 387 if (!local->scan_req || local->scanning) 388 return; 389 390 if (!ieee80211_can_scan(local, 391 rcu_dereference_protected( 392 local->scan_sdata, 393 lockdep_is_held(&local->mtx)))) 394 return; 395 396 ieee80211_queue_delayed_work(&local->hw, &local->scan_work, 397 round_jiffies_relative(0)); 398 } 399 400 static void ieee80211_scan_state_send_probe(struct ieee80211_local *local, 401 unsigned long *next_delay) 402 { 403 int i; 404 struct ieee80211_sub_if_data *sdata; 405 enum ieee80211_band band = local->hw.conf.channel->band; 406 407 sdata = rcu_dereference_protected(local->scan_sdata, 408 lockdep_is_held(&local->mtx)); 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 local->hw.conf.channel, true); 419 420 /* 421 * After sending probe requests, wait for probe responses 422 * on the channel. 423 */ 424 *next_delay = IEEE80211_CHANNEL_TIME; 425 local->next_scan_state = SCAN_DECISION; 426 } 427 428 static int __ieee80211_start_scan(struct ieee80211_sub_if_data *sdata, 429 struct cfg80211_scan_request *req) 430 { 431 struct ieee80211_local *local = sdata->local; 432 int rc; 433 434 lockdep_assert_held(&local->mtx); 435 436 if (local->scan_req) 437 return -EBUSY; 438 439 if (!ieee80211_can_scan(local, sdata)) { 440 /* wait for the work to finish/time out */ 441 local->scan_req = req; 442 rcu_assign_pointer(local->scan_sdata, sdata); 443 return 0; 444 } 445 446 if (local->ops->hw_scan) { 447 u8 *ies; 448 449 local->hw_scan_ies_bufsize = 2 + IEEE80211_MAX_SSID_LEN + 450 local->scan_ies_len + 451 req->ie_len; 452 local->hw_scan_req = kmalloc( 453 sizeof(*local->hw_scan_req) + 454 req->n_channels * sizeof(req->channels[0]) + 455 local->hw_scan_ies_bufsize, GFP_KERNEL); 456 if (!local->hw_scan_req) 457 return -ENOMEM; 458 459 local->hw_scan_req->ssids = req->ssids; 460 local->hw_scan_req->n_ssids = req->n_ssids; 461 ies = (u8 *)local->hw_scan_req + 462 sizeof(*local->hw_scan_req) + 463 req->n_channels * sizeof(req->channels[0]); 464 local->hw_scan_req->ie = ies; 465 local->hw_scan_req->flags = req->flags; 466 467 local->hw_scan_band = 0; 468 469 /* 470 * After allocating local->hw_scan_req, we must 471 * go through until ieee80211_prep_hw_scan(), so 472 * anything that might be changed here and leave 473 * this function early must not go after this 474 * allocation. 475 */ 476 } 477 478 local->scan_req = req; 479 rcu_assign_pointer(local->scan_sdata, sdata); 480 481 if (local->ops->hw_scan) { 482 __set_bit(SCAN_HW_SCANNING, &local->scanning); 483 } else if ((req->n_channels == 1) && 484 (req->channels[0] == local->_oper_channel)) { 485 /* 486 * If we are scanning only on the operating channel 487 * then we do not need to stop normal activities 488 */ 489 unsigned long next_delay; 490 491 __set_bit(SCAN_ONCHANNEL_SCANNING, &local->scanning); 492 493 ieee80211_recalc_idle(local); 494 495 /* Notify driver scan is starting, keep order of operations 496 * same as normal software scan, in case that matters. */ 497 drv_sw_scan_start(local); 498 499 ieee80211_configure_filter(local); /* accept probe-responses */ 500 501 /* We need to ensure power level is at max for scanning. */ 502 ieee80211_hw_config(local, 0); 503 504 if ((req->channels[0]->flags & 505 IEEE80211_CHAN_PASSIVE_SCAN) || 506 !local->scan_req->n_ssids) { 507 next_delay = IEEE80211_PASSIVE_CHANNEL_TIME; 508 } else { 509 ieee80211_scan_state_send_probe(local, &next_delay); 510 next_delay = IEEE80211_CHANNEL_TIME; 511 } 512 513 /* Now, just wait a bit and we are all done! */ 514 ieee80211_queue_delayed_work(&local->hw, &local->scan_work, 515 next_delay); 516 return 0; 517 } else { 518 /* Do normal software scan */ 519 __set_bit(SCAN_SW_SCANNING, &local->scanning); 520 } 521 522 ieee80211_recalc_idle(local); 523 524 if (local->ops->hw_scan) { 525 WARN_ON(!ieee80211_prep_hw_scan(local)); 526 rc = drv_hw_scan(local, sdata, local->hw_scan_req); 527 } else 528 rc = ieee80211_start_sw_scan(local); 529 530 if (rc) { 531 kfree(local->hw_scan_req); 532 local->hw_scan_req = NULL; 533 local->scanning = 0; 534 535 ieee80211_recalc_idle(local); 536 537 local->scan_req = NULL; 538 rcu_assign_pointer(local->scan_sdata, NULL); 539 } 540 541 return rc; 542 } 543 544 static unsigned long 545 ieee80211_scan_get_channel_time(struct ieee80211_channel *chan) 546 { 547 /* 548 * TODO: channel switching also consumes quite some time, 549 * add that delay as well to get a better estimation 550 */ 551 if (chan->flags & IEEE80211_CHAN_PASSIVE_SCAN) 552 return IEEE80211_PASSIVE_CHANNEL_TIME; 553 return IEEE80211_PROBE_DELAY + IEEE80211_CHANNEL_TIME; 554 } 555 556 static void ieee80211_scan_state_decision(struct ieee80211_local *local, 557 unsigned long *next_delay) 558 { 559 bool associated = false; 560 bool tx_empty = true; 561 bool bad_latency; 562 bool listen_int_exceeded; 563 unsigned long min_beacon_int = 0; 564 struct ieee80211_sub_if_data *sdata; 565 struct ieee80211_channel *next_chan; 566 enum mac80211_scan_state next_scan_state; 567 568 /* 569 * check if at least one STA interface is associated, 570 * check if at least one STA interface has pending tx frames 571 * and grab the lowest used beacon interval 572 */ 573 mutex_lock(&local->iflist_mtx); 574 list_for_each_entry(sdata, &local->interfaces, list) { 575 if (!ieee80211_sdata_running(sdata)) 576 continue; 577 578 if (sdata->vif.type == NL80211_IFTYPE_STATION) { 579 if (sdata->u.mgd.associated) { 580 associated = true; 581 582 if (sdata->vif.bss_conf.beacon_int < 583 min_beacon_int || min_beacon_int == 0) 584 min_beacon_int = 585 sdata->vif.bss_conf.beacon_int; 586 587 if (!qdisc_all_tx_empty(sdata->dev)) { 588 tx_empty = false; 589 break; 590 } 591 } 592 } 593 } 594 mutex_unlock(&local->iflist_mtx); 595 596 next_chan = local->scan_req->channels[local->scan_channel_idx]; 597 598 /* 599 * we're currently scanning a different channel, let's 600 * see if we can scan another channel without interfering 601 * with the current traffic situation. 602 * 603 * Since we don't know if the AP has pending frames for us 604 * we can only check for our tx queues and use the current 605 * pm_qos requirements for rx. Hence, if no tx traffic occurs 606 * at all we will scan as many channels in a row as the pm_qos 607 * latency allows us to. Additionally we also check for the 608 * currently negotiated listen interval to prevent losing 609 * frames unnecessarily. 610 * 611 * Otherwise switch back to the operating channel. 612 */ 613 614 bad_latency = time_after(jiffies + 615 ieee80211_scan_get_channel_time(next_chan), 616 local->leave_oper_channel_time + 617 usecs_to_jiffies(pm_qos_request(PM_QOS_NETWORK_LATENCY))); 618 619 listen_int_exceeded = time_after(jiffies + 620 ieee80211_scan_get_channel_time(next_chan), 621 local->leave_oper_channel_time + 622 usecs_to_jiffies(min_beacon_int * 1024) * 623 local->hw.conf.listen_interval); 624 625 if (associated && !tx_empty) { 626 if (local->scan_req->flags & NL80211_SCAN_FLAG_LOW_PRIORITY) 627 next_scan_state = SCAN_ABORT; 628 else 629 next_scan_state = SCAN_SUSPEND; 630 } else if (associated && (bad_latency || listen_int_exceeded)) { 631 next_scan_state = SCAN_SUSPEND; 632 } else { 633 next_scan_state = SCAN_SET_CHANNEL; 634 } 635 636 local->next_scan_state = next_scan_state; 637 638 *next_delay = 0; 639 } 640 641 static void ieee80211_scan_state_set_channel(struct ieee80211_local *local, 642 unsigned long *next_delay) 643 { 644 int skip; 645 struct ieee80211_channel *chan; 646 647 skip = 0; 648 chan = local->scan_req->channels[local->scan_channel_idx]; 649 650 local->scan_channel = chan; 651 652 if (ieee80211_hw_config(local, IEEE80211_CONF_CHANGE_CHANNEL)) 653 skip = 1; 654 655 /* advance state machine to next channel/band */ 656 local->scan_channel_idx++; 657 658 if (skip) { 659 /* if we skip this channel return to the decision state */ 660 local->next_scan_state = SCAN_DECISION; 661 return; 662 } 663 664 /* 665 * Probe delay is used to update the NAV, cf. 11.1.3.2.2 666 * (which unfortunately doesn't say _why_ step a) is done, 667 * but it waits for the probe delay or until a frame is 668 * received - and the received frame would update the NAV). 669 * For now, we do not support waiting until a frame is 670 * received. 671 * 672 * In any case, it is not necessary for a passive scan. 673 */ 674 if (chan->flags & IEEE80211_CHAN_PASSIVE_SCAN || 675 !local->scan_req->n_ssids) { 676 *next_delay = IEEE80211_PASSIVE_CHANNEL_TIME; 677 local->next_scan_state = SCAN_DECISION; 678 return; 679 } 680 681 /* active scan, send probes */ 682 *next_delay = IEEE80211_PROBE_DELAY; 683 local->next_scan_state = SCAN_SEND_PROBE; 684 } 685 686 static void ieee80211_scan_state_suspend(struct ieee80211_local *local, 687 unsigned long *next_delay) 688 { 689 /* switch back to the operating channel */ 690 local->scan_channel = NULL; 691 ieee80211_hw_config(local, IEEE80211_CONF_CHANGE_CHANNEL); 692 693 /* 694 * Re-enable vifs and beaconing. Leave PS 695 * in off-channel state..will put that back 696 * on-channel at the end of scanning. 697 */ 698 ieee80211_offchannel_return(local, false); 699 700 *next_delay = HZ / 5; 701 /* afterwards, resume scan & go to next channel */ 702 local->next_scan_state = SCAN_RESUME; 703 } 704 705 static void ieee80211_scan_state_resume(struct ieee80211_local *local, 706 unsigned long *next_delay) 707 { 708 /* PS already is in off-channel mode */ 709 ieee80211_offchannel_stop_vifs(local, false); 710 711 if (local->ops->flush) { 712 drv_flush(local, false); 713 *next_delay = 0; 714 } else 715 *next_delay = HZ / 10; 716 717 /* remember when we left the operating channel */ 718 local->leave_oper_channel_time = jiffies; 719 720 /* advance to the next channel to be scanned */ 721 local->next_scan_state = SCAN_SET_CHANNEL; 722 } 723 724 void ieee80211_scan_work(struct work_struct *work) 725 { 726 struct ieee80211_local *local = 727 container_of(work, struct ieee80211_local, scan_work.work); 728 struct ieee80211_sub_if_data *sdata; 729 unsigned long next_delay = 0; 730 bool aborted, hw_scan; 731 732 mutex_lock(&local->mtx); 733 734 sdata = rcu_dereference_protected(local->scan_sdata, 735 lockdep_is_held(&local->mtx)); 736 737 /* When scanning on-channel, the first-callback means completed. */ 738 if (test_bit(SCAN_ONCHANNEL_SCANNING, &local->scanning)) { 739 aborted = test_and_clear_bit(SCAN_ABORTED, &local->scanning); 740 goto out_complete; 741 } 742 743 if (test_and_clear_bit(SCAN_COMPLETED, &local->scanning)) { 744 aborted = test_and_clear_bit(SCAN_ABORTED, &local->scanning); 745 goto out_complete; 746 } 747 748 if (!sdata || !local->scan_req) 749 goto out; 750 751 if (local->scan_req && !local->scanning) { 752 struct cfg80211_scan_request *req = local->scan_req; 753 int rc; 754 755 local->scan_req = NULL; 756 rcu_assign_pointer(local->scan_sdata, NULL); 757 758 rc = __ieee80211_start_scan(sdata, req); 759 if (rc) { 760 /* need to complete scan in cfg80211 */ 761 local->scan_req = req; 762 aborted = true; 763 goto out_complete; 764 } else 765 goto out; 766 } 767 768 /* 769 * Avoid re-scheduling when the sdata is going away. 770 */ 771 if (!ieee80211_sdata_running(sdata)) { 772 aborted = true; 773 goto out_complete; 774 } 775 776 /* 777 * as long as no delay is required advance immediately 778 * without scheduling a new work 779 */ 780 do { 781 if (!ieee80211_sdata_running(sdata)) { 782 aborted = true; 783 goto out_complete; 784 } 785 786 switch (local->next_scan_state) { 787 case SCAN_DECISION: 788 /* if no more bands/channels left, complete scan */ 789 if (local->scan_channel_idx >= local->scan_req->n_channels) { 790 aborted = false; 791 goto out_complete; 792 } 793 ieee80211_scan_state_decision(local, &next_delay); 794 break; 795 case SCAN_SET_CHANNEL: 796 ieee80211_scan_state_set_channel(local, &next_delay); 797 break; 798 case SCAN_SEND_PROBE: 799 ieee80211_scan_state_send_probe(local, &next_delay); 800 break; 801 case SCAN_SUSPEND: 802 ieee80211_scan_state_suspend(local, &next_delay); 803 break; 804 case SCAN_RESUME: 805 ieee80211_scan_state_resume(local, &next_delay); 806 break; 807 case SCAN_ABORT: 808 aborted = true; 809 goto out_complete; 810 } 811 } while (next_delay == 0); 812 813 ieee80211_queue_delayed_work(&local->hw, &local->scan_work, next_delay); 814 goto out; 815 816 out_complete: 817 hw_scan = test_bit(SCAN_HW_SCANNING, &local->scanning); 818 __ieee80211_scan_completed(&local->hw, aborted, hw_scan); 819 out: 820 mutex_unlock(&local->mtx); 821 } 822 823 int ieee80211_request_scan(struct ieee80211_sub_if_data *sdata, 824 struct cfg80211_scan_request *req) 825 { 826 int res; 827 828 mutex_lock(&sdata->local->mtx); 829 res = __ieee80211_start_scan(sdata, req); 830 mutex_unlock(&sdata->local->mtx); 831 832 return res; 833 } 834 835 int ieee80211_request_internal_scan(struct ieee80211_sub_if_data *sdata, 836 const u8 *ssid, u8 ssid_len, 837 struct ieee80211_channel *chan) 838 { 839 struct ieee80211_local *local = sdata->local; 840 int ret = -EBUSY; 841 enum ieee80211_band band; 842 843 mutex_lock(&local->mtx); 844 845 /* busy scanning */ 846 if (local->scan_req) 847 goto unlock; 848 849 /* fill internal scan request */ 850 if (!chan) { 851 int i, nchan = 0; 852 853 for (band = 0; band < IEEE80211_NUM_BANDS; band++) { 854 if (!local->hw.wiphy->bands[band]) 855 continue; 856 for (i = 0; 857 i < local->hw.wiphy->bands[band]->n_channels; 858 i++) { 859 local->int_scan_req->channels[nchan] = 860 &local->hw.wiphy->bands[band]->channels[i]; 861 nchan++; 862 } 863 } 864 865 local->int_scan_req->n_channels = nchan; 866 } else { 867 local->int_scan_req->channels[0] = chan; 868 local->int_scan_req->n_channels = 1; 869 } 870 871 local->int_scan_req->ssids = &local->scan_ssid; 872 local->int_scan_req->n_ssids = 1; 873 memcpy(local->int_scan_req->ssids[0].ssid, ssid, IEEE80211_MAX_SSID_LEN); 874 local->int_scan_req->ssids[0].ssid_len = ssid_len; 875 876 ret = __ieee80211_start_scan(sdata, sdata->local->int_scan_req); 877 unlock: 878 mutex_unlock(&local->mtx); 879 return ret; 880 } 881 882 /* 883 * Only call this function when a scan can't be queued -- under RTNL. 884 */ 885 void ieee80211_scan_cancel(struct ieee80211_local *local) 886 { 887 /* 888 * We are canceling software scan, or deferred scan that was not 889 * yet really started (see __ieee80211_start_scan ). 890 * 891 * Regarding hardware scan: 892 * - we can not call __ieee80211_scan_completed() as when 893 * SCAN_HW_SCANNING bit is set this function change 894 * local->hw_scan_req to operate on 5G band, what race with 895 * driver which can use local->hw_scan_req 896 * 897 * - we can not cancel scan_work since driver can schedule it 898 * by ieee80211_scan_completed(..., true) to finish scan 899 * 900 * Hence we only call the cancel_hw_scan() callback, but the low-level 901 * driver is still responsible for calling ieee80211_scan_completed() 902 * after the scan was completed/aborted. 903 */ 904 905 mutex_lock(&local->mtx); 906 if (!local->scan_req) 907 goto out; 908 909 if (test_bit(SCAN_HW_SCANNING, &local->scanning)) { 910 if (local->ops->cancel_hw_scan) 911 drv_cancel_hw_scan(local, 912 rcu_dereference_protected(local->scan_sdata, 913 lockdep_is_held(&local->mtx))); 914 goto out; 915 } 916 917 /* 918 * If the work is currently running, it must be blocked on 919 * the mutex, but we'll set scan_sdata = NULL and it'll 920 * simply exit once it acquires the mutex. 921 */ 922 cancel_delayed_work(&local->scan_work); 923 /* and clean up */ 924 __ieee80211_scan_completed(&local->hw, true, false); 925 out: 926 mutex_unlock(&local->mtx); 927 } 928 929 int ieee80211_request_sched_scan_start(struct ieee80211_sub_if_data *sdata, 930 struct cfg80211_sched_scan_request *req) 931 { 932 struct ieee80211_local *local = sdata->local; 933 struct ieee80211_sched_scan_ies sched_scan_ies = {}; 934 int ret, i, iebufsz; 935 936 iebufsz = 2 + IEEE80211_MAX_SSID_LEN + 937 local->scan_ies_len + req->ie_len; 938 939 mutex_lock(&local->mtx); 940 941 if (rcu_access_pointer(local->sched_scan_sdata)) { 942 ret = -EBUSY; 943 goto out; 944 } 945 946 if (!local->ops->sched_scan_start) { 947 ret = -ENOTSUPP; 948 goto out; 949 } 950 951 for (i = 0; i < IEEE80211_NUM_BANDS; i++) { 952 if (!local->hw.wiphy->bands[i]) 953 continue; 954 955 sched_scan_ies.ie[i] = kzalloc(iebufsz, GFP_KERNEL); 956 if (!sched_scan_ies.ie[i]) { 957 ret = -ENOMEM; 958 goto out_free; 959 } 960 961 sched_scan_ies.len[i] = 962 ieee80211_build_preq_ies(local, sched_scan_ies.ie[i], 963 iebufsz, req->ie, req->ie_len, 964 i, (u32) -1, 0); 965 } 966 967 ret = drv_sched_scan_start(local, sdata, req, &sched_scan_ies); 968 if (ret == 0) 969 rcu_assign_pointer(local->sched_scan_sdata, sdata); 970 971 out_free: 972 while (i > 0) 973 kfree(sched_scan_ies.ie[--i]); 974 out: 975 mutex_unlock(&local->mtx); 976 return ret; 977 } 978 979 int ieee80211_request_sched_scan_stop(struct ieee80211_sub_if_data *sdata) 980 { 981 struct ieee80211_local *local = sdata->local; 982 int ret = 0; 983 984 mutex_lock(&local->mtx); 985 986 if (!local->ops->sched_scan_stop) { 987 ret = -ENOTSUPP; 988 goto out; 989 } 990 991 if (rcu_access_pointer(local->sched_scan_sdata)) 992 drv_sched_scan_stop(local, sdata); 993 994 out: 995 mutex_unlock(&local->mtx); 996 997 return ret; 998 } 999 1000 void ieee80211_sched_scan_results(struct ieee80211_hw *hw) 1001 { 1002 struct ieee80211_local *local = hw_to_local(hw); 1003 1004 trace_api_sched_scan_results(local); 1005 1006 cfg80211_sched_scan_results(hw->wiphy); 1007 } 1008 EXPORT_SYMBOL(ieee80211_sched_scan_results); 1009 1010 void ieee80211_sched_scan_stopped_work(struct work_struct *work) 1011 { 1012 struct ieee80211_local *local = 1013 container_of(work, struct ieee80211_local, 1014 sched_scan_stopped_work); 1015 1016 mutex_lock(&local->mtx); 1017 1018 if (!rcu_access_pointer(local->sched_scan_sdata)) { 1019 mutex_unlock(&local->mtx); 1020 return; 1021 } 1022 1023 rcu_assign_pointer(local->sched_scan_sdata, NULL); 1024 1025 mutex_unlock(&local->mtx); 1026 1027 cfg80211_sched_scan_stopped(local->hw.wiphy); 1028 } 1029 1030 void ieee80211_sched_scan_stopped(struct ieee80211_hw *hw) 1031 { 1032 struct ieee80211_local *local = hw_to_local(hw); 1033 1034 trace_api_sched_scan_stopped(local); 1035 1036 ieee80211_queue_work(&local->hw, &local->sched_scan_stopped_work); 1037 } 1038 EXPORT_SYMBOL(ieee80211_sched_scan_stopped); 1039