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 /* 340 * Hardware/driver doesn't support hw_scan, so use software 341 * scanning instead. First send a nullfunc frame with power save 342 * bit on so that AP will buffer the frames for us while we are not 343 * listening, then send probe requests to each channel and wait for 344 * the responses. After all channels are scanned, tune back to the 345 * original channel and send a nullfunc frame with power save bit 346 * off to trigger the AP to send us all the buffered frames. 347 * 348 * Note that while local->sw_scanning is true everything else but 349 * nullfunc frames and probe requests will be dropped in 350 * ieee80211_tx_h_check_assoc(). 351 */ 352 drv_sw_scan_start(local); 353 354 local->leave_oper_channel_time = jiffies; 355 local->next_scan_state = SCAN_DECISION; 356 local->scan_channel_idx = 0; 357 358 ieee80211_offchannel_stop_vifs(local, true); 359 360 ieee80211_configure_filter(local); 361 362 /* We need to set power level at maximum rate for scanning. */ 363 ieee80211_hw_config(local, 0); 364 365 ieee80211_queue_delayed_work(&local->hw, 366 &local->scan_work, 0); 367 368 return 0; 369 } 370 371 static bool ieee80211_can_scan(struct ieee80211_local *local, 372 struct ieee80211_sub_if_data *sdata) 373 { 374 if (!list_empty(&local->roc_list)) 375 return false; 376 377 if (sdata->vif.type == NL80211_IFTYPE_STATION && 378 sdata->u.mgd.flags & (IEEE80211_STA_BEACON_POLL | 379 IEEE80211_STA_CONNECTION_POLL)) 380 return false; 381 382 return true; 383 } 384 385 void ieee80211_run_deferred_scan(struct ieee80211_local *local) 386 { 387 lockdep_assert_held(&local->mtx); 388 389 if (!local->scan_req || local->scanning) 390 return; 391 392 if (!ieee80211_can_scan(local, 393 rcu_dereference_protected( 394 local->scan_sdata, 395 lockdep_is_held(&local->mtx)))) 396 return; 397 398 ieee80211_queue_delayed_work(&local->hw, &local->scan_work, 399 round_jiffies_relative(0)); 400 } 401 402 static void ieee80211_scan_state_send_probe(struct ieee80211_local *local, 403 unsigned long *next_delay) 404 { 405 int i; 406 struct ieee80211_sub_if_data *sdata; 407 enum ieee80211_band band = local->hw.conf.channel->band; 408 409 sdata = rcu_dereference_protected(local->scan_sdata, 410 lockdep_is_held(&local->mtx)); 411 412 for (i = 0; i < local->scan_req->n_ssids; i++) 413 ieee80211_send_probe_req( 414 sdata, NULL, 415 local->scan_req->ssids[i].ssid, 416 local->scan_req->ssids[i].ssid_len, 417 local->scan_req->ie, local->scan_req->ie_len, 418 local->scan_req->rates[band], false, 419 local->scan_req->no_cck, 420 local->hw.conf.channel); 421 422 /* 423 * After sending probe requests, wait for probe responses 424 * on the channel. 425 */ 426 *next_delay = IEEE80211_CHANNEL_TIME; 427 local->next_scan_state = SCAN_DECISION; 428 } 429 430 static int __ieee80211_start_scan(struct ieee80211_sub_if_data *sdata, 431 struct cfg80211_scan_request *req) 432 { 433 struct ieee80211_local *local = sdata->local; 434 int rc; 435 436 lockdep_assert_held(&local->mtx); 437 438 if (local->scan_req) 439 return -EBUSY; 440 441 if (!ieee80211_can_scan(local, sdata)) { 442 /* wait for the work to finish/time out */ 443 local->scan_req = req; 444 rcu_assign_pointer(local->scan_sdata, sdata); 445 return 0; 446 } 447 448 if (local->ops->hw_scan) { 449 u8 *ies; 450 451 local->hw_scan_req = kmalloc( 452 sizeof(*local->hw_scan_req) + 453 req->n_channels * sizeof(req->channels[0]) + 454 2 + IEEE80211_MAX_SSID_LEN + local->scan_ies_len + 455 req->ie_len, 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; 465 466 local->hw_scan_band = 0; 467 468 /* 469 * After allocating local->hw_scan_req, we must 470 * go through until ieee80211_prep_hw_scan(), so 471 * anything that might be changed here and leave 472 * this function early must not go after this 473 * allocation. 474 */ 475 } 476 477 local->scan_req = req; 478 rcu_assign_pointer(local->scan_sdata, sdata); 479 480 if (local->ops->hw_scan) { 481 __set_bit(SCAN_HW_SCANNING, &local->scanning); 482 } else if ((req->n_channels == 1) && 483 (req->channels[0] == local->oper_channel)) { 484 /* 485 * If we are scanning only on the operating channel 486 * then we do not need to stop normal activities 487 */ 488 unsigned long next_delay; 489 490 __set_bit(SCAN_ONCHANNEL_SCANNING, &local->scanning); 491 492 ieee80211_recalc_idle(local); 493 494 /* Notify driver scan is starting, keep order of operations 495 * same as normal software scan, in case that matters. */ 496 drv_sw_scan_start(local); 497 498 ieee80211_configure_filter(local); /* accept probe-responses */ 499 500 /* We need to ensure power level is at max for scanning. */ 501 ieee80211_hw_config(local, 0); 502 503 if ((req->channels[0]->flags & 504 IEEE80211_CHAN_PASSIVE_SCAN) || 505 !local->scan_req->n_ssids) { 506 next_delay = IEEE80211_PASSIVE_CHANNEL_TIME; 507 } else { 508 ieee80211_scan_state_send_probe(local, &next_delay); 509 next_delay = IEEE80211_CHANNEL_TIME; 510 } 511 512 /* Now, just wait a bit and we are all done! */ 513 ieee80211_queue_delayed_work(&local->hw, &local->scan_work, 514 next_delay); 515 return 0; 516 } else { 517 /* Do normal software scan */ 518 __set_bit(SCAN_SW_SCANNING, &local->scanning); 519 } 520 521 ieee80211_recalc_idle(local); 522 523 if (local->ops->hw_scan) { 524 WARN_ON(!ieee80211_prep_hw_scan(local)); 525 rc = drv_hw_scan(local, sdata, local->hw_scan_req); 526 } else 527 rc = ieee80211_start_sw_scan(local); 528 529 if (rc) { 530 kfree(local->hw_scan_req); 531 local->hw_scan_req = NULL; 532 local->scanning = 0; 533 534 ieee80211_recalc_idle(local); 535 536 local->scan_req = NULL; 537 rcu_assign_pointer(local->scan_sdata, NULL); 538 } 539 540 return rc; 541 } 542 543 static unsigned long 544 ieee80211_scan_get_channel_time(struct ieee80211_channel *chan) 545 { 546 /* 547 * TODO: channel switching also consumes quite some time, 548 * add that delay as well to get a better estimation 549 */ 550 if (chan->flags & IEEE80211_CHAN_PASSIVE_SCAN) 551 return IEEE80211_PASSIVE_CHANNEL_TIME; 552 return IEEE80211_PROBE_DELAY + IEEE80211_CHANNEL_TIME; 553 } 554 555 static void ieee80211_scan_state_decision(struct ieee80211_local *local, 556 unsigned long *next_delay) 557 { 558 bool associated = false; 559 bool tx_empty = true; 560 bool bad_latency; 561 bool listen_int_exceeded; 562 unsigned long min_beacon_int = 0; 563 struct ieee80211_sub_if_data *sdata; 564 struct ieee80211_channel *next_chan; 565 566 /* 567 * check if at least one STA interface is associated, 568 * check if at least one STA interface has pending tx frames 569 * and grab the lowest used beacon interval 570 */ 571 mutex_lock(&local->iflist_mtx); 572 list_for_each_entry(sdata, &local->interfaces, list) { 573 if (!ieee80211_sdata_running(sdata)) 574 continue; 575 576 if (sdata->vif.type == NL80211_IFTYPE_STATION) { 577 if (sdata->u.mgd.associated) { 578 associated = true; 579 580 if (sdata->vif.bss_conf.beacon_int < 581 min_beacon_int || min_beacon_int == 0) 582 min_beacon_int = 583 sdata->vif.bss_conf.beacon_int; 584 585 if (!qdisc_all_tx_empty(sdata->dev)) { 586 tx_empty = false; 587 break; 588 } 589 } 590 } 591 } 592 mutex_unlock(&local->iflist_mtx); 593 594 next_chan = local->scan_req->channels[local->scan_channel_idx]; 595 596 /* 597 * we're currently scanning a different channel, let's 598 * see if we can scan another channel without interfering 599 * with the current traffic situation. 600 * 601 * Since we don't know if the AP has pending frames for us 602 * we can only check for our tx queues and use the current 603 * pm_qos requirements for rx. Hence, if no tx traffic occurs 604 * at all we will scan as many channels in a row as the pm_qos 605 * latency allows us to. Additionally we also check for the 606 * currently negotiated listen interval to prevent losing 607 * frames unnecessarily. 608 * 609 * Otherwise switch back to the operating channel. 610 */ 611 612 bad_latency = time_after(jiffies + 613 ieee80211_scan_get_channel_time(next_chan), 614 local->leave_oper_channel_time + 615 usecs_to_jiffies(pm_qos_request(PM_QOS_NETWORK_LATENCY))); 616 617 listen_int_exceeded = time_after(jiffies + 618 ieee80211_scan_get_channel_time(next_chan), 619 local->leave_oper_channel_time + 620 usecs_to_jiffies(min_beacon_int * 1024) * 621 local->hw.conf.listen_interval); 622 623 if (associated && (!tx_empty || bad_latency || listen_int_exceeded)) 624 local->next_scan_state = SCAN_SUSPEND; 625 else 626 local->next_scan_state = SCAN_SET_CHANNEL; 627 628 *next_delay = 0; 629 } 630 631 static void ieee80211_scan_state_set_channel(struct ieee80211_local *local, 632 unsigned long *next_delay) 633 { 634 int skip; 635 struct ieee80211_channel *chan; 636 637 skip = 0; 638 chan = local->scan_req->channels[local->scan_channel_idx]; 639 640 local->scan_channel = chan; 641 642 if (ieee80211_hw_config(local, IEEE80211_CONF_CHANGE_CHANNEL)) 643 skip = 1; 644 645 /* advance state machine to next channel/band */ 646 local->scan_channel_idx++; 647 648 if (skip) { 649 /* if we skip this channel return to the decision state */ 650 local->next_scan_state = SCAN_DECISION; 651 return; 652 } 653 654 /* 655 * Probe delay is used to update the NAV, cf. 11.1.3.2.2 656 * (which unfortunately doesn't say _why_ step a) is done, 657 * but it waits for the probe delay or until a frame is 658 * received - and the received frame would update the NAV). 659 * For now, we do not support waiting until a frame is 660 * received. 661 * 662 * In any case, it is not necessary for a passive scan. 663 */ 664 if (chan->flags & IEEE80211_CHAN_PASSIVE_SCAN || 665 !local->scan_req->n_ssids) { 666 *next_delay = IEEE80211_PASSIVE_CHANNEL_TIME; 667 local->next_scan_state = SCAN_DECISION; 668 return; 669 } 670 671 /* active scan, send probes */ 672 *next_delay = IEEE80211_PROBE_DELAY; 673 local->next_scan_state = SCAN_SEND_PROBE; 674 } 675 676 static void ieee80211_scan_state_suspend(struct ieee80211_local *local, 677 unsigned long *next_delay) 678 { 679 /* switch back to the operating channel */ 680 local->scan_channel = NULL; 681 ieee80211_hw_config(local, IEEE80211_CONF_CHANGE_CHANNEL); 682 683 /* 684 * Re-enable vifs and beaconing. Leave PS 685 * in off-channel state..will put that back 686 * on-channel at the end of scanning. 687 */ 688 ieee80211_offchannel_return(local, false); 689 690 *next_delay = HZ / 5; 691 /* afterwards, resume scan & go to next channel */ 692 local->next_scan_state = SCAN_RESUME; 693 } 694 695 static void ieee80211_scan_state_resume(struct ieee80211_local *local, 696 unsigned long *next_delay) 697 { 698 /* PS already is in off-channel mode */ 699 ieee80211_offchannel_stop_vifs(local, false); 700 701 if (local->ops->flush) { 702 drv_flush(local, false); 703 *next_delay = 0; 704 } else 705 *next_delay = HZ / 10; 706 707 /* remember when we left the operating channel */ 708 local->leave_oper_channel_time = jiffies; 709 710 /* advance to the next channel to be scanned */ 711 local->next_scan_state = SCAN_SET_CHANNEL; 712 } 713 714 void ieee80211_scan_work(struct work_struct *work) 715 { 716 struct ieee80211_local *local = 717 container_of(work, struct ieee80211_local, scan_work.work); 718 struct ieee80211_sub_if_data *sdata; 719 unsigned long next_delay = 0; 720 bool aborted, hw_scan; 721 722 mutex_lock(&local->mtx); 723 724 sdata = rcu_dereference_protected(local->scan_sdata, 725 lockdep_is_held(&local->mtx)); 726 727 /* When scanning on-channel, the first-callback means completed. */ 728 if (test_bit(SCAN_ONCHANNEL_SCANNING, &local->scanning)) { 729 aborted = test_and_clear_bit(SCAN_ABORTED, &local->scanning); 730 goto out_complete; 731 } 732 733 if (test_and_clear_bit(SCAN_COMPLETED, &local->scanning)) { 734 aborted = test_and_clear_bit(SCAN_ABORTED, &local->scanning); 735 goto out_complete; 736 } 737 738 if (!sdata || !local->scan_req) 739 goto out; 740 741 if (local->scan_req && !local->scanning) { 742 struct cfg80211_scan_request *req = local->scan_req; 743 int rc; 744 745 local->scan_req = NULL; 746 rcu_assign_pointer(local->scan_sdata, NULL); 747 748 rc = __ieee80211_start_scan(sdata, req); 749 if (rc) { 750 /* need to complete scan in cfg80211 */ 751 local->scan_req = req; 752 aborted = true; 753 goto out_complete; 754 } else 755 goto out; 756 } 757 758 /* 759 * Avoid re-scheduling when the sdata is going away. 760 */ 761 if (!ieee80211_sdata_running(sdata)) { 762 aborted = true; 763 goto out_complete; 764 } 765 766 /* 767 * as long as no delay is required advance immediately 768 * without scheduling a new work 769 */ 770 do { 771 if (!ieee80211_sdata_running(sdata)) { 772 aborted = true; 773 goto out_complete; 774 } 775 776 switch (local->next_scan_state) { 777 case SCAN_DECISION: 778 /* if no more bands/channels left, complete scan */ 779 if (local->scan_channel_idx >= local->scan_req->n_channels) { 780 aborted = false; 781 goto out_complete; 782 } 783 ieee80211_scan_state_decision(local, &next_delay); 784 break; 785 case SCAN_SET_CHANNEL: 786 ieee80211_scan_state_set_channel(local, &next_delay); 787 break; 788 case SCAN_SEND_PROBE: 789 ieee80211_scan_state_send_probe(local, &next_delay); 790 break; 791 case SCAN_SUSPEND: 792 ieee80211_scan_state_suspend(local, &next_delay); 793 break; 794 case SCAN_RESUME: 795 ieee80211_scan_state_resume(local, &next_delay); 796 break; 797 } 798 } while (next_delay == 0); 799 800 ieee80211_queue_delayed_work(&local->hw, &local->scan_work, next_delay); 801 goto out; 802 803 out_complete: 804 hw_scan = test_bit(SCAN_HW_SCANNING, &local->scanning); 805 __ieee80211_scan_completed(&local->hw, aborted, hw_scan); 806 out: 807 mutex_unlock(&local->mtx); 808 } 809 810 int ieee80211_request_scan(struct ieee80211_sub_if_data *sdata, 811 struct cfg80211_scan_request *req) 812 { 813 int res; 814 815 mutex_lock(&sdata->local->mtx); 816 res = __ieee80211_start_scan(sdata, req); 817 mutex_unlock(&sdata->local->mtx); 818 819 return res; 820 } 821 822 int ieee80211_request_internal_scan(struct ieee80211_sub_if_data *sdata, 823 const u8 *ssid, u8 ssid_len, 824 struct ieee80211_channel *chan) 825 { 826 struct ieee80211_local *local = sdata->local; 827 int ret = -EBUSY; 828 enum ieee80211_band band; 829 830 mutex_lock(&local->mtx); 831 832 /* busy scanning */ 833 if (local->scan_req) 834 goto unlock; 835 836 /* fill internal scan request */ 837 if (!chan) { 838 int i, nchan = 0; 839 840 for (band = 0; band < IEEE80211_NUM_BANDS; band++) { 841 if (!local->hw.wiphy->bands[band]) 842 continue; 843 for (i = 0; 844 i < local->hw.wiphy->bands[band]->n_channels; 845 i++) { 846 local->int_scan_req->channels[nchan] = 847 &local->hw.wiphy->bands[band]->channels[i]; 848 nchan++; 849 } 850 } 851 852 local->int_scan_req->n_channels = nchan; 853 } else { 854 local->int_scan_req->channels[0] = chan; 855 local->int_scan_req->n_channels = 1; 856 } 857 858 local->int_scan_req->ssids = &local->scan_ssid; 859 local->int_scan_req->n_ssids = 1; 860 memcpy(local->int_scan_req->ssids[0].ssid, ssid, IEEE80211_MAX_SSID_LEN); 861 local->int_scan_req->ssids[0].ssid_len = ssid_len; 862 863 ret = __ieee80211_start_scan(sdata, sdata->local->int_scan_req); 864 unlock: 865 mutex_unlock(&local->mtx); 866 return ret; 867 } 868 869 /* 870 * Only call this function when a scan can't be queued -- under RTNL. 871 */ 872 void ieee80211_scan_cancel(struct ieee80211_local *local) 873 { 874 /* 875 * We are canceling software scan, or deferred scan that was not 876 * yet really started (see __ieee80211_start_scan ). 877 * 878 * Regarding hardware scan: 879 * - we can not call __ieee80211_scan_completed() as when 880 * SCAN_HW_SCANNING bit is set this function change 881 * local->hw_scan_req to operate on 5G band, what race with 882 * driver which can use local->hw_scan_req 883 * 884 * - we can not cancel scan_work since driver can schedule it 885 * by ieee80211_scan_completed(..., true) to finish scan 886 * 887 * Hence we only call the cancel_hw_scan() callback, but the low-level 888 * driver is still responsible for calling ieee80211_scan_completed() 889 * after the scan was completed/aborted. 890 */ 891 892 mutex_lock(&local->mtx); 893 if (!local->scan_req) 894 goto out; 895 896 if (test_bit(SCAN_HW_SCANNING, &local->scanning)) { 897 if (local->ops->cancel_hw_scan) 898 drv_cancel_hw_scan(local, 899 rcu_dereference_protected(local->scan_sdata, 900 lockdep_is_held(&local->mtx))); 901 goto out; 902 } 903 904 /* 905 * If the work is currently running, it must be blocked on 906 * the mutex, but we'll set scan_sdata = NULL and it'll 907 * simply exit once it acquires the mutex. 908 */ 909 cancel_delayed_work(&local->scan_work); 910 /* and clean up */ 911 __ieee80211_scan_completed(&local->hw, true, false); 912 out: 913 mutex_unlock(&local->mtx); 914 } 915 916 int ieee80211_request_sched_scan_start(struct ieee80211_sub_if_data *sdata, 917 struct cfg80211_sched_scan_request *req) 918 { 919 struct ieee80211_local *local = sdata->local; 920 struct ieee80211_sched_scan_ies sched_scan_ies = {}; 921 int ret, i; 922 923 mutex_lock(&local->mtx); 924 925 if (rcu_access_pointer(local->sched_scan_sdata)) { 926 ret = -EBUSY; 927 goto out; 928 } 929 930 if (!local->ops->sched_scan_start) { 931 ret = -ENOTSUPP; 932 goto out; 933 } 934 935 for (i = 0; i < IEEE80211_NUM_BANDS; i++) { 936 if (!local->hw.wiphy->bands[i]) 937 continue; 938 939 sched_scan_ies.ie[i] = kzalloc(2 + IEEE80211_MAX_SSID_LEN + 940 local->scan_ies_len + 941 req->ie_len, 942 GFP_KERNEL); 943 if (!sched_scan_ies.ie[i]) { 944 ret = -ENOMEM; 945 goto out_free; 946 } 947 948 sched_scan_ies.len[i] = 949 ieee80211_build_preq_ies(local, sched_scan_ies.ie[i], 950 req->ie, req->ie_len, i, 951 (u32) -1, 0); 952 } 953 954 ret = drv_sched_scan_start(local, sdata, req, &sched_scan_ies); 955 if (ret == 0) 956 rcu_assign_pointer(local->sched_scan_sdata, sdata); 957 958 out_free: 959 while (i > 0) 960 kfree(sched_scan_ies.ie[--i]); 961 out: 962 mutex_unlock(&local->mtx); 963 return ret; 964 } 965 966 int ieee80211_request_sched_scan_stop(struct ieee80211_sub_if_data *sdata) 967 { 968 struct ieee80211_local *local = sdata->local; 969 int ret = 0; 970 971 mutex_lock(&local->mtx); 972 973 if (!local->ops->sched_scan_stop) { 974 ret = -ENOTSUPP; 975 goto out; 976 } 977 978 if (rcu_access_pointer(local->sched_scan_sdata)) 979 drv_sched_scan_stop(local, sdata); 980 981 out: 982 mutex_unlock(&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 1003 mutex_lock(&local->mtx); 1004 1005 if (!rcu_access_pointer(local->sched_scan_sdata)) { 1006 mutex_unlock(&local->mtx); 1007 return; 1008 } 1009 1010 rcu_assign_pointer(local->sched_scan_sdata, NULL); 1011 1012 mutex_unlock(&local->mtx); 1013 1014 cfg80211_sched_scan_stopped(local->hw.wiphy); 1015 } 1016 1017 void ieee80211_sched_scan_stopped(struct ieee80211_hw *hw) 1018 { 1019 struct ieee80211_local *local = hw_to_local(hw); 1020 1021 trace_api_sched_scan_stopped(local); 1022 1023 ieee80211_queue_work(&local->hw, &local->sched_scan_stopped_work); 1024 } 1025 EXPORT_SYMBOL(ieee80211_sched_scan_stopped); 1026