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 int freq; 178 bool beacon; 179 struct ieee802_11_elems elems; 180 181 if (skb->len < 24 || 182 (!ieee80211_is_probe_resp(mgmt->frame_control) && 183 !ieee80211_is_beacon(mgmt->frame_control))) 184 return; 185 186 sdata1 = rcu_dereference(local->scan_sdata); 187 sdata2 = rcu_dereference(local->sched_scan_sdata); 188 189 if (likely(!sdata1 && !sdata2)) 190 return; 191 192 if (ieee80211_is_probe_resp(mgmt->frame_control)) { 193 /* ignore ProbeResp to foreign address */ 194 if ((!sdata1 || !ether_addr_equal(mgmt->da, sdata1->vif.addr)) && 195 (!sdata2 || !ether_addr_equal(mgmt->da, sdata2->vif.addr))) 196 return; 197 198 elements = mgmt->u.probe_resp.variable; 199 baselen = offsetof(struct ieee80211_mgmt, u.probe_resp.variable); 200 beacon = false; 201 } else { 202 baselen = offsetof(struct ieee80211_mgmt, u.beacon.variable); 203 elements = mgmt->u.beacon.variable; 204 beacon = true; 205 } 206 207 if (baselen > skb->len) 208 return; 209 210 ieee802_11_parse_elems(elements, skb->len - baselen, &elems); 211 212 if (elems.ds_params && elems.ds_params_len == 1) 213 freq = ieee80211_channel_to_frequency(elems.ds_params[0], 214 rx_status->band); 215 else 216 freq = rx_status->freq; 217 218 channel = ieee80211_get_channel(local->hw.wiphy, freq); 219 220 if (!channel || channel->flags & IEEE80211_CHAN_DISABLED) 221 return; 222 223 bss = ieee80211_bss_info_update(local, rx_status, 224 mgmt, skb->len, &elems, 225 channel, beacon); 226 if (bss) 227 ieee80211_rx_bss_put(local, bss); 228 } 229 230 /* return false if no more work */ 231 static bool ieee80211_prep_hw_scan(struct ieee80211_local *local) 232 { 233 struct cfg80211_scan_request *req = local->scan_req; 234 enum ieee80211_band band; 235 int i, ielen, n_chans; 236 237 do { 238 if (local->hw_scan_band == IEEE80211_NUM_BANDS) 239 return false; 240 241 band = local->hw_scan_band; 242 n_chans = 0; 243 for (i = 0; i < req->n_channels; i++) { 244 if (req->channels[i]->band == band) { 245 local->hw_scan_req->channels[n_chans] = 246 req->channels[i]; 247 n_chans++; 248 } 249 } 250 251 local->hw_scan_band++; 252 } while (!n_chans); 253 254 local->hw_scan_req->n_channels = n_chans; 255 256 ielen = ieee80211_build_preq_ies(local, (u8 *)local->hw_scan_req->ie, 257 req->ie, req->ie_len, band, 258 req->rates[band], 0); 259 local->hw_scan_req->ie_len = ielen; 260 local->hw_scan_req->no_cck = req->no_cck; 261 262 return true; 263 } 264 265 static void __ieee80211_scan_completed(struct ieee80211_hw *hw, bool aborted, 266 bool was_hw_scan) 267 { 268 struct ieee80211_local *local = hw_to_local(hw); 269 270 lockdep_assert_held(&local->mtx); 271 272 /* 273 * It's ok to abort a not-yet-running scan (that 274 * we have one at all will be verified by checking 275 * local->scan_req next), but not to complete it 276 * successfully. 277 */ 278 if (WARN_ON(!local->scanning && !aborted)) 279 aborted = true; 280 281 if (WARN_ON(!local->scan_req)) 282 return; 283 284 if (was_hw_scan && !aborted && ieee80211_prep_hw_scan(local)) { 285 int rc; 286 287 rc = drv_hw_scan(local, 288 rcu_dereference_protected(local->scan_sdata, 289 lockdep_is_held(&local->mtx)), 290 local->hw_scan_req); 291 292 if (rc == 0) 293 return; 294 } 295 296 kfree(local->hw_scan_req); 297 local->hw_scan_req = NULL; 298 299 if (local->scan_req != local->int_scan_req) 300 cfg80211_scan_done(local->scan_req, aborted); 301 local->scan_req = NULL; 302 rcu_assign_pointer(local->scan_sdata, NULL); 303 304 local->scanning = 0; 305 local->scan_channel = NULL; 306 307 /* Set power back to normal operating levels. */ 308 ieee80211_hw_config(local, 0); 309 310 if (!was_hw_scan) { 311 ieee80211_configure_filter(local); 312 drv_sw_scan_complete(local); 313 ieee80211_offchannel_return(local, true); 314 } 315 316 ieee80211_recalc_idle(local); 317 318 ieee80211_mlme_notify_scan_completed(local); 319 ieee80211_ibss_notify_scan_completed(local); 320 ieee80211_mesh_notify_scan_completed(local); 321 ieee80211_start_next_roc(local); 322 } 323 324 void ieee80211_scan_completed(struct ieee80211_hw *hw, bool aborted) 325 { 326 struct ieee80211_local *local = hw_to_local(hw); 327 328 trace_api_scan_completed(local, aborted); 329 330 set_bit(SCAN_COMPLETED, &local->scanning); 331 if (aborted) 332 set_bit(SCAN_ABORTED, &local->scanning); 333 ieee80211_queue_delayed_work(&local->hw, &local->scan_work, 0); 334 } 335 EXPORT_SYMBOL(ieee80211_scan_completed); 336 337 static int ieee80211_start_sw_scan(struct ieee80211_local *local) 338 { 339 /* Software scan is not supported in multi-channel cases */ 340 if (local->use_chanctx) 341 return -EOPNOTSUPP; 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, 397 rcu_dereference_protected( 398 local->scan_sdata, 399 lockdep_is_held(&local->mtx)))) 400 return; 401 402 ieee80211_queue_delayed_work(&local->hw, &local->scan_work, 403 round_jiffies_relative(0)); 404 } 405 406 static void ieee80211_scan_state_send_probe(struct ieee80211_local *local, 407 unsigned long *next_delay) 408 { 409 int i; 410 struct ieee80211_sub_if_data *sdata; 411 enum ieee80211_band band = local->hw.conf.channel->band; 412 413 sdata = rcu_dereference_protected(local->scan_sdata, 414 lockdep_is_held(&local->mtx)); 415 416 for (i = 0; i < local->scan_req->n_ssids; i++) 417 ieee80211_send_probe_req( 418 sdata, NULL, 419 local->scan_req->ssids[i].ssid, 420 local->scan_req->ssids[i].ssid_len, 421 local->scan_req->ie, local->scan_req->ie_len, 422 local->scan_req->rates[band], false, 423 local->scan_req->no_cck, 424 local->hw.conf.channel); 425 426 /* 427 * After sending probe requests, wait for probe responses 428 * on the channel. 429 */ 430 *next_delay = IEEE80211_CHANNEL_TIME; 431 local->next_scan_state = SCAN_DECISION; 432 } 433 434 static int __ieee80211_start_scan(struct ieee80211_sub_if_data *sdata, 435 struct cfg80211_scan_request *req) 436 { 437 struct ieee80211_local *local = sdata->local; 438 int rc; 439 440 lockdep_assert_held(&local->mtx); 441 442 if (local->scan_req) 443 return -EBUSY; 444 445 if (!ieee80211_can_scan(local, sdata)) { 446 /* wait for the work to finish/time out */ 447 local->scan_req = req; 448 rcu_assign_pointer(local->scan_sdata, sdata); 449 return 0; 450 } 451 452 if (local->ops->hw_scan) { 453 u8 *ies; 454 455 local->hw_scan_req = kmalloc( 456 sizeof(*local->hw_scan_req) + 457 req->n_channels * sizeof(req->channels[0]) + 458 2 + IEEE80211_MAX_SSID_LEN + local->scan_ies_len + 459 req->ie_len, GFP_KERNEL); 460 if (!local->hw_scan_req) 461 return -ENOMEM; 462 463 local->hw_scan_req->ssids = req->ssids; 464 local->hw_scan_req->n_ssids = req->n_ssids; 465 ies = (u8 *)local->hw_scan_req + 466 sizeof(*local->hw_scan_req) + 467 req->n_channels * sizeof(req->channels[0]); 468 local->hw_scan_req->ie = ies; 469 470 local->hw_scan_band = 0; 471 472 /* 473 * After allocating local->hw_scan_req, we must 474 * go through until ieee80211_prep_hw_scan(), so 475 * anything that might be changed here and leave 476 * this function early must not go after this 477 * allocation. 478 */ 479 } 480 481 local->scan_req = req; 482 rcu_assign_pointer(local->scan_sdata, sdata); 483 484 if (local->ops->hw_scan) { 485 __set_bit(SCAN_HW_SCANNING, &local->scanning); 486 } else if ((req->n_channels == 1) && 487 (req->channels[0] == local->oper_channel)) { 488 /* 489 * If we are scanning only on the operating channel 490 * then we do not need to stop normal activities 491 */ 492 unsigned long next_delay; 493 494 __set_bit(SCAN_ONCHANNEL_SCANNING, &local->scanning); 495 496 ieee80211_recalc_idle(local); 497 498 /* Notify driver scan is starting, keep order of operations 499 * same as normal software scan, in case that matters. */ 500 drv_sw_scan_start(local); 501 502 ieee80211_configure_filter(local); /* accept probe-responses */ 503 504 /* We need to ensure power level is at max for scanning. */ 505 ieee80211_hw_config(local, 0); 506 507 if ((req->channels[0]->flags & 508 IEEE80211_CHAN_PASSIVE_SCAN) || 509 !local->scan_req->n_ssids) { 510 next_delay = IEEE80211_PASSIVE_CHANNEL_TIME; 511 } else { 512 ieee80211_scan_state_send_probe(local, &next_delay); 513 next_delay = IEEE80211_CHANNEL_TIME; 514 } 515 516 /* Now, just wait a bit and we are all done! */ 517 ieee80211_queue_delayed_work(&local->hw, &local->scan_work, 518 next_delay); 519 return 0; 520 } else { 521 /* Do normal software scan */ 522 __set_bit(SCAN_SW_SCANNING, &local->scanning); 523 } 524 525 ieee80211_recalc_idle(local); 526 527 if (local->ops->hw_scan) { 528 WARN_ON(!ieee80211_prep_hw_scan(local)); 529 rc = drv_hw_scan(local, sdata, local->hw_scan_req); 530 } else 531 rc = ieee80211_start_sw_scan(local); 532 533 if (rc) { 534 kfree(local->hw_scan_req); 535 local->hw_scan_req = NULL; 536 local->scanning = 0; 537 538 ieee80211_recalc_idle(local); 539 540 local->scan_req = NULL; 541 rcu_assign_pointer(local->scan_sdata, NULL); 542 } 543 544 return rc; 545 } 546 547 static unsigned long 548 ieee80211_scan_get_channel_time(struct ieee80211_channel *chan) 549 { 550 /* 551 * TODO: channel switching also consumes quite some time, 552 * add that delay as well to get a better estimation 553 */ 554 if (chan->flags & IEEE80211_CHAN_PASSIVE_SCAN) 555 return IEEE80211_PASSIVE_CHANNEL_TIME; 556 return IEEE80211_PROBE_DELAY + IEEE80211_CHANNEL_TIME; 557 } 558 559 static void ieee80211_scan_state_decision(struct ieee80211_local *local, 560 unsigned long *next_delay) 561 { 562 bool associated = false; 563 bool tx_empty = true; 564 bool bad_latency; 565 bool listen_int_exceeded; 566 unsigned long min_beacon_int = 0; 567 struct ieee80211_sub_if_data *sdata; 568 struct ieee80211_channel *next_chan; 569 570 /* 571 * check if at least one STA interface is associated, 572 * check if at least one STA interface has pending tx frames 573 * and grab the lowest used beacon interval 574 */ 575 mutex_lock(&local->iflist_mtx); 576 list_for_each_entry(sdata, &local->interfaces, list) { 577 if (!ieee80211_sdata_running(sdata)) 578 continue; 579 580 if (sdata->vif.type == NL80211_IFTYPE_STATION) { 581 if (sdata->u.mgd.associated) { 582 associated = true; 583 584 if (sdata->vif.bss_conf.beacon_int < 585 min_beacon_int || min_beacon_int == 0) 586 min_beacon_int = 587 sdata->vif.bss_conf.beacon_int; 588 589 if (!qdisc_all_tx_empty(sdata->dev)) { 590 tx_empty = false; 591 break; 592 } 593 } 594 } 595 } 596 mutex_unlock(&local->iflist_mtx); 597 598 next_chan = local->scan_req->channels[local->scan_channel_idx]; 599 600 /* 601 * we're currently scanning a different channel, let's 602 * see if we can scan another channel without interfering 603 * with the current traffic situation. 604 * 605 * Since we don't know if the AP has pending frames for us 606 * we can only check for our tx queues and use the current 607 * pm_qos requirements for rx. Hence, if no tx traffic occurs 608 * at all we will scan as many channels in a row as the pm_qos 609 * latency allows us to. Additionally we also check for the 610 * currently negotiated listen interval to prevent losing 611 * frames unnecessarily. 612 * 613 * Otherwise switch back to the operating channel. 614 */ 615 616 bad_latency = time_after(jiffies + 617 ieee80211_scan_get_channel_time(next_chan), 618 local->leave_oper_channel_time + 619 usecs_to_jiffies(pm_qos_request(PM_QOS_NETWORK_LATENCY))); 620 621 listen_int_exceeded = time_after(jiffies + 622 ieee80211_scan_get_channel_time(next_chan), 623 local->leave_oper_channel_time + 624 usecs_to_jiffies(min_beacon_int * 1024) * 625 local->hw.conf.listen_interval); 626 627 if (associated && (!tx_empty || bad_latency || listen_int_exceeded)) 628 local->next_scan_state = SCAN_SUSPEND; 629 else 630 local->next_scan_state = SCAN_SET_CHANNEL; 631 632 *next_delay = 0; 633 } 634 635 static void ieee80211_scan_state_set_channel(struct ieee80211_local *local, 636 unsigned long *next_delay) 637 { 638 int skip; 639 struct ieee80211_channel *chan; 640 641 skip = 0; 642 chan = local->scan_req->channels[local->scan_channel_idx]; 643 644 local->scan_channel = chan; 645 646 if (ieee80211_hw_config(local, IEEE80211_CONF_CHANGE_CHANNEL)) 647 skip = 1; 648 649 /* advance state machine to next channel/band */ 650 local->scan_channel_idx++; 651 652 if (skip) { 653 /* if we skip this channel return to the decision state */ 654 local->next_scan_state = SCAN_DECISION; 655 return; 656 } 657 658 /* 659 * Probe delay is used to update the NAV, cf. 11.1.3.2.2 660 * (which unfortunately doesn't say _why_ step a) is done, 661 * but it waits for the probe delay or until a frame is 662 * received - and the received frame would update the NAV). 663 * For now, we do not support waiting until a frame is 664 * received. 665 * 666 * In any case, it is not necessary for a passive scan. 667 */ 668 if (chan->flags & IEEE80211_CHAN_PASSIVE_SCAN || 669 !local->scan_req->n_ssids) { 670 *next_delay = IEEE80211_PASSIVE_CHANNEL_TIME; 671 local->next_scan_state = SCAN_DECISION; 672 return; 673 } 674 675 /* active scan, send probes */ 676 *next_delay = IEEE80211_PROBE_DELAY; 677 local->next_scan_state = SCAN_SEND_PROBE; 678 } 679 680 static void ieee80211_scan_state_suspend(struct ieee80211_local *local, 681 unsigned long *next_delay) 682 { 683 /* switch back to the operating channel */ 684 local->scan_channel = NULL; 685 ieee80211_hw_config(local, IEEE80211_CONF_CHANGE_CHANNEL); 686 687 /* 688 * Re-enable vifs and beaconing. Leave PS 689 * in off-channel state..will put that back 690 * on-channel at the end of scanning. 691 */ 692 ieee80211_offchannel_return(local, false); 693 694 *next_delay = HZ / 5; 695 /* afterwards, resume scan & go to next channel */ 696 local->next_scan_state = SCAN_RESUME; 697 } 698 699 static void ieee80211_scan_state_resume(struct ieee80211_local *local, 700 unsigned long *next_delay) 701 { 702 /* PS already is in off-channel mode */ 703 ieee80211_offchannel_stop_vifs(local, false); 704 705 if (local->ops->flush) { 706 drv_flush(local, false); 707 *next_delay = 0; 708 } else 709 *next_delay = HZ / 10; 710 711 /* remember when we left the operating channel */ 712 local->leave_oper_channel_time = jiffies; 713 714 /* advance to the next channel to be scanned */ 715 local->next_scan_state = SCAN_SET_CHANNEL; 716 } 717 718 void ieee80211_scan_work(struct work_struct *work) 719 { 720 struct ieee80211_local *local = 721 container_of(work, struct ieee80211_local, scan_work.work); 722 struct ieee80211_sub_if_data *sdata; 723 unsigned long next_delay = 0; 724 bool aborted, hw_scan; 725 726 mutex_lock(&local->mtx); 727 728 sdata = rcu_dereference_protected(local->scan_sdata, 729 lockdep_is_held(&local->mtx)); 730 731 /* When scanning on-channel, the first-callback means completed. */ 732 if (test_bit(SCAN_ONCHANNEL_SCANNING, &local->scanning)) { 733 aborted = test_and_clear_bit(SCAN_ABORTED, &local->scanning); 734 goto out_complete; 735 } 736 737 if (test_and_clear_bit(SCAN_COMPLETED, &local->scanning)) { 738 aborted = test_and_clear_bit(SCAN_ABORTED, &local->scanning); 739 goto out_complete; 740 } 741 742 if (!sdata || !local->scan_req) 743 goto out; 744 745 if (local->scan_req && !local->scanning) { 746 struct cfg80211_scan_request *req = local->scan_req; 747 int rc; 748 749 local->scan_req = NULL; 750 rcu_assign_pointer(local->scan_sdata, NULL); 751 752 rc = __ieee80211_start_scan(sdata, req); 753 if (rc) { 754 /* need to complete scan in cfg80211 */ 755 local->scan_req = req; 756 aborted = true; 757 goto out_complete; 758 } else 759 goto out; 760 } 761 762 /* 763 * Avoid re-scheduling when the sdata is going away. 764 */ 765 if (!ieee80211_sdata_running(sdata)) { 766 aborted = true; 767 goto out_complete; 768 } 769 770 /* 771 * as long as no delay is required advance immediately 772 * without scheduling a new work 773 */ 774 do { 775 if (!ieee80211_sdata_running(sdata)) { 776 aborted = true; 777 goto out_complete; 778 } 779 780 switch (local->next_scan_state) { 781 case SCAN_DECISION: 782 /* if no more bands/channels left, complete scan */ 783 if (local->scan_channel_idx >= local->scan_req->n_channels) { 784 aborted = false; 785 goto out_complete; 786 } 787 ieee80211_scan_state_decision(local, &next_delay); 788 break; 789 case SCAN_SET_CHANNEL: 790 ieee80211_scan_state_set_channel(local, &next_delay); 791 break; 792 case SCAN_SEND_PROBE: 793 ieee80211_scan_state_send_probe(local, &next_delay); 794 break; 795 case SCAN_SUSPEND: 796 ieee80211_scan_state_suspend(local, &next_delay); 797 break; 798 case SCAN_RESUME: 799 ieee80211_scan_state_resume(local, &next_delay); 800 break; 801 } 802 } while (next_delay == 0); 803 804 ieee80211_queue_delayed_work(&local->hw, &local->scan_work, next_delay); 805 goto out; 806 807 out_complete: 808 hw_scan = test_bit(SCAN_HW_SCANNING, &local->scanning); 809 __ieee80211_scan_completed(&local->hw, aborted, hw_scan); 810 out: 811 mutex_unlock(&local->mtx); 812 } 813 814 int ieee80211_request_scan(struct ieee80211_sub_if_data *sdata, 815 struct cfg80211_scan_request *req) 816 { 817 int res; 818 819 mutex_lock(&sdata->local->mtx); 820 res = __ieee80211_start_scan(sdata, req); 821 mutex_unlock(&sdata->local->mtx); 822 823 return res; 824 } 825 826 int ieee80211_request_internal_scan(struct ieee80211_sub_if_data *sdata, 827 const u8 *ssid, u8 ssid_len, 828 struct ieee80211_channel *chan) 829 { 830 struct ieee80211_local *local = sdata->local; 831 int ret = -EBUSY; 832 enum ieee80211_band band; 833 834 mutex_lock(&local->mtx); 835 836 /* busy scanning */ 837 if (local->scan_req) 838 goto unlock; 839 840 /* fill internal scan request */ 841 if (!chan) { 842 int i, nchan = 0; 843 844 for (band = 0; band < IEEE80211_NUM_BANDS; band++) { 845 if (!local->hw.wiphy->bands[band]) 846 continue; 847 for (i = 0; 848 i < local->hw.wiphy->bands[band]->n_channels; 849 i++) { 850 local->int_scan_req->channels[nchan] = 851 &local->hw.wiphy->bands[band]->channels[i]; 852 nchan++; 853 } 854 } 855 856 local->int_scan_req->n_channels = nchan; 857 } else { 858 local->int_scan_req->channels[0] = chan; 859 local->int_scan_req->n_channels = 1; 860 } 861 862 local->int_scan_req->ssids = &local->scan_ssid; 863 local->int_scan_req->n_ssids = 1; 864 memcpy(local->int_scan_req->ssids[0].ssid, ssid, IEEE80211_MAX_SSID_LEN); 865 local->int_scan_req->ssids[0].ssid_len = ssid_len; 866 867 ret = __ieee80211_start_scan(sdata, sdata->local->int_scan_req); 868 unlock: 869 mutex_unlock(&local->mtx); 870 return ret; 871 } 872 873 /* 874 * Only call this function when a scan can't be queued -- under RTNL. 875 */ 876 void ieee80211_scan_cancel(struct ieee80211_local *local) 877 { 878 /* 879 * We are canceling software scan, or deferred scan that was not 880 * yet really started (see __ieee80211_start_scan ). 881 * 882 * Regarding hardware scan: 883 * - we can not call __ieee80211_scan_completed() as when 884 * SCAN_HW_SCANNING bit is set this function change 885 * local->hw_scan_req to operate on 5G band, what race with 886 * driver which can use local->hw_scan_req 887 * 888 * - we can not cancel scan_work since driver can schedule it 889 * by ieee80211_scan_completed(..., true) to finish scan 890 * 891 * Hence we only call the cancel_hw_scan() callback, but the low-level 892 * driver is still responsible for calling ieee80211_scan_completed() 893 * after the scan was completed/aborted. 894 */ 895 896 mutex_lock(&local->mtx); 897 if (!local->scan_req) 898 goto out; 899 900 if (test_bit(SCAN_HW_SCANNING, &local->scanning)) { 901 if (local->ops->cancel_hw_scan) 902 drv_cancel_hw_scan(local, 903 rcu_dereference_protected(local->scan_sdata, 904 lockdep_is_held(&local->mtx))); 905 goto out; 906 } 907 908 /* 909 * If the work is currently running, it must be blocked on 910 * the mutex, but we'll set scan_sdata = NULL and it'll 911 * simply exit once it acquires the mutex. 912 */ 913 cancel_delayed_work(&local->scan_work); 914 /* and clean up */ 915 __ieee80211_scan_completed(&local->hw, true, false); 916 out: 917 mutex_unlock(&local->mtx); 918 } 919 920 int ieee80211_request_sched_scan_start(struct ieee80211_sub_if_data *sdata, 921 struct cfg80211_sched_scan_request *req) 922 { 923 struct ieee80211_local *local = sdata->local; 924 struct ieee80211_sched_scan_ies sched_scan_ies; 925 int ret, i; 926 927 mutex_lock(&local->mtx); 928 929 if (rcu_access_pointer(local->sched_scan_sdata)) { 930 ret = -EBUSY; 931 goto out; 932 } 933 934 if (!local->ops->sched_scan_start) { 935 ret = -ENOTSUPP; 936 goto out; 937 } 938 939 for (i = 0; i < IEEE80211_NUM_BANDS; i++) { 940 if (!local->hw.wiphy->bands[i]) 941 continue; 942 943 sched_scan_ies.ie[i] = kzalloc(2 + IEEE80211_MAX_SSID_LEN + 944 local->scan_ies_len + 945 req->ie_len, 946 GFP_KERNEL); 947 if (!sched_scan_ies.ie[i]) { 948 ret = -ENOMEM; 949 goto out_free; 950 } 951 952 sched_scan_ies.len[i] = 953 ieee80211_build_preq_ies(local, sched_scan_ies.ie[i], 954 req->ie, req->ie_len, i, 955 (u32) -1, 0); 956 } 957 958 ret = drv_sched_scan_start(local, sdata, req, &sched_scan_ies); 959 if (ret == 0) 960 rcu_assign_pointer(local->sched_scan_sdata, sdata); 961 962 out_free: 963 while (i > 0) 964 kfree(sched_scan_ies.ie[--i]); 965 out: 966 mutex_unlock(&local->mtx); 967 return ret; 968 } 969 970 int ieee80211_request_sched_scan_stop(struct ieee80211_sub_if_data *sdata) 971 { 972 struct ieee80211_local *local = sdata->local; 973 int ret = 0; 974 975 mutex_lock(&local->mtx); 976 977 if (!local->ops->sched_scan_stop) { 978 ret = -ENOTSUPP; 979 goto out; 980 } 981 982 if (rcu_access_pointer(local->sched_scan_sdata)) 983 drv_sched_scan_stop(local, sdata); 984 985 out: 986 mutex_unlock(&local->mtx); 987 988 return ret; 989 } 990 991 void ieee80211_sched_scan_results(struct ieee80211_hw *hw) 992 { 993 struct ieee80211_local *local = hw_to_local(hw); 994 995 trace_api_sched_scan_results(local); 996 997 cfg80211_sched_scan_results(hw->wiphy); 998 } 999 EXPORT_SYMBOL(ieee80211_sched_scan_results); 1000 1001 void ieee80211_sched_scan_stopped_work(struct work_struct *work) 1002 { 1003 struct ieee80211_local *local = 1004 container_of(work, struct ieee80211_local, 1005 sched_scan_stopped_work); 1006 1007 mutex_lock(&local->mtx); 1008 1009 if (!rcu_access_pointer(local->sched_scan_sdata)) { 1010 mutex_unlock(&local->mtx); 1011 return; 1012 } 1013 1014 rcu_assign_pointer(local->sched_scan_sdata, NULL); 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); 1030