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 / 9) 31 32 void ieee80211_rx_bss_put(struct ieee80211_local *local, 33 struct ieee80211_bss *bss) 34 { 35 if (!bss) 36 return; 37 cfg80211_put_bss(local->hw.wiphy, 38 container_of((void *)bss, struct cfg80211_bss, priv)); 39 } 40 41 static bool is_uapsd_supported(struct ieee802_11_elems *elems) 42 { 43 u8 qos_info; 44 45 if (elems->wmm_info && elems->wmm_info_len == 7 46 && elems->wmm_info[5] == 1) 47 qos_info = elems->wmm_info[6]; 48 else if (elems->wmm_param && elems->wmm_param_len == 24 49 && elems->wmm_param[5] == 1) 50 qos_info = elems->wmm_param[6]; 51 else 52 /* no valid wmm information or parameter element found */ 53 return false; 54 55 return qos_info & IEEE80211_WMM_IE_AP_QOSINFO_UAPSD; 56 } 57 58 struct ieee80211_bss * 59 ieee80211_bss_info_update(struct ieee80211_local *local, 60 struct ieee80211_rx_status *rx_status, 61 struct ieee80211_mgmt *mgmt, size_t len, 62 struct ieee802_11_elems *elems, 63 struct ieee80211_channel *channel) 64 { 65 bool beacon = ieee80211_is_beacon(mgmt->frame_control); 66 struct cfg80211_bss *cbss; 67 struct ieee80211_bss *bss; 68 int clen, srlen; 69 enum nl80211_bss_scan_width scan_width; 70 s32 signal = 0; 71 72 if (local->hw.flags & IEEE80211_HW_SIGNAL_DBM) 73 signal = rx_status->signal * 100; 74 else if (local->hw.flags & IEEE80211_HW_SIGNAL_UNSPEC) 75 signal = (rx_status->signal * 100) / local->hw.max_signal; 76 77 scan_width = NL80211_BSS_CHAN_WIDTH_20; 78 if (rx_status->flag & RX_FLAG_5MHZ) 79 scan_width = NL80211_BSS_CHAN_WIDTH_5; 80 if (rx_status->flag & RX_FLAG_10MHZ) 81 scan_width = NL80211_BSS_CHAN_WIDTH_10; 82 83 cbss = cfg80211_inform_bss_width_frame(local->hw.wiphy, channel, 84 scan_width, mgmt, len, signal, 85 GFP_ATOMIC); 86 if (!cbss) 87 return NULL; 88 89 bss = (void *)cbss->priv; 90 91 if (beacon) 92 bss->device_ts_beacon = rx_status->device_timestamp; 93 else 94 bss->device_ts_presp = rx_status->device_timestamp; 95 96 if (elems->parse_error) { 97 if (beacon) 98 bss->corrupt_data |= IEEE80211_BSS_CORRUPT_BEACON; 99 else 100 bss->corrupt_data |= IEEE80211_BSS_CORRUPT_PROBE_RESP; 101 } else { 102 if (beacon) 103 bss->corrupt_data &= ~IEEE80211_BSS_CORRUPT_BEACON; 104 else 105 bss->corrupt_data &= ~IEEE80211_BSS_CORRUPT_PROBE_RESP; 106 } 107 108 /* save the ERP value so that it is available at association time */ 109 if (elems->erp_info && (!elems->parse_error || 110 !(bss->valid_data & IEEE80211_BSS_VALID_ERP))) { 111 bss->erp_value = elems->erp_info[0]; 112 bss->has_erp_value = true; 113 if (!elems->parse_error) 114 bss->valid_data |= IEEE80211_BSS_VALID_ERP; 115 } 116 117 /* replace old supported rates if we get new values */ 118 if (!elems->parse_error || 119 !(bss->valid_data & IEEE80211_BSS_VALID_RATES)) { 120 srlen = 0; 121 if (elems->supp_rates) { 122 clen = IEEE80211_MAX_SUPP_RATES; 123 if (clen > elems->supp_rates_len) 124 clen = elems->supp_rates_len; 125 memcpy(bss->supp_rates, elems->supp_rates, clen); 126 srlen += clen; 127 } 128 if (elems->ext_supp_rates) { 129 clen = IEEE80211_MAX_SUPP_RATES - srlen; 130 if (clen > elems->ext_supp_rates_len) 131 clen = elems->ext_supp_rates_len; 132 memcpy(bss->supp_rates + srlen, elems->ext_supp_rates, 133 clen); 134 srlen += clen; 135 } 136 if (srlen) { 137 bss->supp_rates_len = srlen; 138 if (!elems->parse_error) 139 bss->valid_data |= IEEE80211_BSS_VALID_RATES; 140 } 141 } 142 143 if (!elems->parse_error || 144 !(bss->valid_data & IEEE80211_BSS_VALID_WMM)) { 145 bss->wmm_used = elems->wmm_param || elems->wmm_info; 146 bss->uapsd_supported = is_uapsd_supported(elems); 147 if (!elems->parse_error) 148 bss->valid_data |= IEEE80211_BSS_VALID_WMM; 149 } 150 151 if (beacon) { 152 struct ieee80211_supported_band *sband = 153 local->hw.wiphy->bands[rx_status->band]; 154 if (!(rx_status->flag & RX_FLAG_HT) && 155 !(rx_status->flag & RX_FLAG_VHT)) 156 bss->beacon_rate = 157 &sband->bitrates[rx_status->rate_idx]; 158 } 159 160 return bss; 161 } 162 163 void ieee80211_scan_rx(struct ieee80211_local *local, struct sk_buff *skb) 164 { 165 struct ieee80211_rx_status *rx_status = IEEE80211_SKB_RXCB(skb); 166 struct ieee80211_sub_if_data *sdata1, *sdata2; 167 struct ieee80211_mgmt *mgmt = (void *)skb->data; 168 struct ieee80211_bss *bss; 169 u8 *elements; 170 struct ieee80211_channel *channel; 171 size_t baselen; 172 struct ieee802_11_elems elems; 173 174 if (skb->len < 24 || 175 (!ieee80211_is_probe_resp(mgmt->frame_control) && 176 !ieee80211_is_beacon(mgmt->frame_control))) 177 return; 178 179 sdata1 = rcu_dereference(local->scan_sdata); 180 sdata2 = rcu_dereference(local->sched_scan_sdata); 181 182 if (likely(!sdata1 && !sdata2)) 183 return; 184 185 if (ieee80211_is_probe_resp(mgmt->frame_control)) { 186 /* ignore ProbeResp to foreign address */ 187 if ((!sdata1 || !ether_addr_equal(mgmt->da, sdata1->vif.addr)) && 188 (!sdata2 || !ether_addr_equal(mgmt->da, sdata2->vif.addr))) 189 return; 190 191 elements = mgmt->u.probe_resp.variable; 192 baselen = offsetof(struct ieee80211_mgmt, u.probe_resp.variable); 193 } else { 194 baselen = offsetof(struct ieee80211_mgmt, u.beacon.variable); 195 elements = mgmt->u.beacon.variable; 196 } 197 198 if (baselen > skb->len) 199 return; 200 201 ieee802_11_parse_elems(elements, skb->len - baselen, false, &elems); 202 203 channel = ieee80211_get_channel(local->hw.wiphy, rx_status->freq); 204 205 if (!channel || channel->flags & IEEE80211_CHAN_DISABLED) 206 return; 207 208 bss = ieee80211_bss_info_update(local, rx_status, 209 mgmt, skb->len, &elems, 210 channel); 211 if (bss) 212 ieee80211_rx_bss_put(local, bss); 213 } 214 215 static void 216 ieee80211_prepare_scan_chandef(struct cfg80211_chan_def *chandef, 217 enum nl80211_bss_scan_width scan_width) 218 { 219 memset(chandef, 0, sizeof(*chandef)); 220 switch (scan_width) { 221 case NL80211_BSS_CHAN_WIDTH_5: 222 chandef->width = NL80211_CHAN_WIDTH_5; 223 break; 224 case NL80211_BSS_CHAN_WIDTH_10: 225 chandef->width = NL80211_CHAN_WIDTH_10; 226 break; 227 default: 228 chandef->width = NL80211_CHAN_WIDTH_20_NOHT; 229 break; 230 } 231 } 232 233 /* return false if no more work */ 234 static bool ieee80211_prep_hw_scan(struct ieee80211_local *local) 235 { 236 struct cfg80211_scan_request *req = local->scan_req; 237 struct cfg80211_chan_def chandef; 238 enum ieee80211_band band; 239 int i, ielen, n_chans; 240 241 if (test_bit(SCAN_HW_CANCELLED, &local->scanning)) 242 return false; 243 244 do { 245 if (local->hw_scan_band == IEEE80211_NUM_BANDS) 246 return false; 247 248 band = local->hw_scan_band; 249 n_chans = 0; 250 for (i = 0; i < req->n_channels; i++) { 251 if (req->channels[i]->band == band) { 252 local->hw_scan_req->channels[n_chans] = 253 req->channels[i]; 254 n_chans++; 255 } 256 } 257 258 local->hw_scan_band++; 259 } while (!n_chans); 260 261 local->hw_scan_req->n_channels = n_chans; 262 ieee80211_prepare_scan_chandef(&chandef, req->scan_width); 263 264 ielen = ieee80211_build_preq_ies(local, (u8 *)local->hw_scan_req->ie, 265 local->hw_scan_ies_bufsize, 266 req->ie, req->ie_len, band, 267 req->rates[band], &chandef); 268 local->hw_scan_req->ie_len = ielen; 269 local->hw_scan_req->no_cck = req->no_cck; 270 271 return true; 272 } 273 274 static void __ieee80211_scan_completed(struct ieee80211_hw *hw, bool aborted) 275 { 276 struct ieee80211_local *local = hw_to_local(hw); 277 bool hw_scan = local->ops->hw_scan; 278 bool was_scanning = local->scanning; 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 (hw_scan && !aborted && ieee80211_prep_hw_scan(local)) { 295 int rc; 296 297 rc = drv_hw_scan(local, 298 rcu_dereference_protected(local->scan_sdata, 299 lockdep_is_held(&local->mtx)), 300 local->hw_scan_req); 301 302 if (rc == 0) 303 return; 304 } 305 306 kfree(local->hw_scan_req); 307 local->hw_scan_req = NULL; 308 309 if (local->scan_req != local->int_scan_req) 310 cfg80211_scan_done(local->scan_req, aborted); 311 local->scan_req = NULL; 312 rcu_assign_pointer(local->scan_sdata, NULL); 313 314 local->scanning = 0; 315 local->scan_chandef.chan = NULL; 316 317 /* Set power back to normal operating levels. */ 318 ieee80211_hw_config(local, 0); 319 320 if (!hw_scan) { 321 ieee80211_configure_filter(local); 322 drv_sw_scan_complete(local); 323 ieee80211_offchannel_return(local); 324 } 325 326 ieee80211_recalc_idle(local); 327 328 ieee80211_mlme_notify_scan_completed(local); 329 ieee80211_ibss_notify_scan_completed(local); 330 ieee80211_mesh_notify_scan_completed(local); 331 if (was_scanning) 332 ieee80211_start_next_roc(local); 333 } 334 335 void ieee80211_scan_completed(struct ieee80211_hw *hw, bool aborted) 336 { 337 struct ieee80211_local *local = hw_to_local(hw); 338 339 trace_api_scan_completed(local, aborted); 340 341 set_bit(SCAN_COMPLETED, &local->scanning); 342 if (aborted) 343 set_bit(SCAN_ABORTED, &local->scanning); 344 ieee80211_queue_delayed_work(&local->hw, &local->scan_work, 0); 345 } 346 EXPORT_SYMBOL(ieee80211_scan_completed); 347 348 static int ieee80211_start_sw_scan(struct ieee80211_local *local) 349 { 350 /* Software scan is not supported in multi-channel cases */ 351 if (local->use_chanctx) 352 return -EOPNOTSUPP; 353 354 /* 355 * Hardware/driver doesn't support hw_scan, so use software 356 * scanning instead. First send a nullfunc frame with power save 357 * bit on so that AP will buffer the frames for us while we are not 358 * listening, then send probe requests to each channel and wait for 359 * the responses. After all channels are scanned, tune back to the 360 * original channel and send a nullfunc frame with power save bit 361 * off to trigger the AP to send us all the buffered frames. 362 * 363 * Note that while local->sw_scanning is true everything else but 364 * nullfunc frames and probe requests will be dropped in 365 * ieee80211_tx_h_check_assoc(). 366 */ 367 drv_sw_scan_start(local); 368 369 local->leave_oper_channel_time = jiffies; 370 local->next_scan_state = SCAN_DECISION; 371 local->scan_channel_idx = 0; 372 373 ieee80211_offchannel_stop_vifs(local); 374 375 /* ensure nullfunc is transmitted before leaving operating channel */ 376 ieee80211_flush_queues(local, NULL); 377 378 ieee80211_configure_filter(local); 379 380 /* We need to set power level at maximum rate for scanning. */ 381 ieee80211_hw_config(local, 0); 382 383 ieee80211_queue_delayed_work(&local->hw, 384 &local->scan_work, 0); 385 386 return 0; 387 } 388 389 static bool ieee80211_can_scan(struct ieee80211_local *local, 390 struct ieee80211_sub_if_data *sdata) 391 { 392 if (local->radar_detect_enabled) 393 return false; 394 395 if (!list_empty(&local->roc_list)) 396 return false; 397 398 if (sdata->vif.type == NL80211_IFTYPE_STATION && 399 sdata->u.mgd.flags & IEEE80211_STA_CONNECTION_POLL) 400 return false; 401 402 return true; 403 } 404 405 void ieee80211_run_deferred_scan(struct ieee80211_local *local) 406 { 407 lockdep_assert_held(&local->mtx); 408 409 if (!local->scan_req || local->scanning) 410 return; 411 412 if (!ieee80211_can_scan(local, 413 rcu_dereference_protected( 414 local->scan_sdata, 415 lockdep_is_held(&local->mtx)))) 416 return; 417 418 ieee80211_queue_delayed_work(&local->hw, &local->scan_work, 419 round_jiffies_relative(0)); 420 } 421 422 static void ieee80211_scan_state_send_probe(struct ieee80211_local *local, 423 unsigned long *next_delay) 424 { 425 int i; 426 struct ieee80211_sub_if_data *sdata; 427 enum ieee80211_band band = local->hw.conf.chandef.chan->band; 428 u32 tx_flags; 429 430 tx_flags = IEEE80211_TX_INTFL_OFFCHAN_TX_OK; 431 if (local->scan_req->no_cck) 432 tx_flags |= IEEE80211_TX_CTL_NO_CCK_RATE; 433 434 sdata = rcu_dereference_protected(local->scan_sdata, 435 lockdep_is_held(&local->mtx)); 436 437 for (i = 0; i < local->scan_req->n_ssids; i++) 438 ieee80211_send_probe_req( 439 sdata, NULL, 440 local->scan_req->ssids[i].ssid, 441 local->scan_req->ssids[i].ssid_len, 442 local->scan_req->ie, local->scan_req->ie_len, 443 local->scan_req->rates[band], false, 444 tx_flags, local->hw.conf.chandef.chan, true); 445 446 /* 447 * After sending probe requests, wait for probe responses 448 * on the channel. 449 */ 450 *next_delay = IEEE80211_CHANNEL_TIME; 451 local->next_scan_state = SCAN_DECISION; 452 } 453 454 static int __ieee80211_start_scan(struct ieee80211_sub_if_data *sdata, 455 struct cfg80211_scan_request *req) 456 { 457 struct ieee80211_local *local = sdata->local; 458 int rc; 459 460 lockdep_assert_held(&local->mtx); 461 462 if (local->scan_req) 463 return -EBUSY; 464 465 if (!ieee80211_can_scan(local, sdata)) { 466 /* wait for the work to finish/time out */ 467 local->scan_req = req; 468 rcu_assign_pointer(local->scan_sdata, sdata); 469 return 0; 470 } 471 472 if (local->ops->hw_scan) { 473 u8 *ies; 474 475 local->hw_scan_ies_bufsize = 2 + IEEE80211_MAX_SSID_LEN + 476 local->scan_ies_len + 477 req->ie_len; 478 local->hw_scan_req = kmalloc( 479 sizeof(*local->hw_scan_req) + 480 req->n_channels * sizeof(req->channels[0]) + 481 local->hw_scan_ies_bufsize, GFP_KERNEL); 482 if (!local->hw_scan_req) 483 return -ENOMEM; 484 485 local->hw_scan_req->ssids = req->ssids; 486 local->hw_scan_req->n_ssids = req->n_ssids; 487 ies = (u8 *)local->hw_scan_req + 488 sizeof(*local->hw_scan_req) + 489 req->n_channels * sizeof(req->channels[0]); 490 local->hw_scan_req->ie = ies; 491 local->hw_scan_req->flags = req->flags; 492 493 local->hw_scan_band = 0; 494 495 /* 496 * After allocating local->hw_scan_req, we must 497 * go through until ieee80211_prep_hw_scan(), so 498 * anything that might be changed here and leave 499 * this function early must not go after this 500 * allocation. 501 */ 502 } 503 504 local->scan_req = req; 505 rcu_assign_pointer(local->scan_sdata, sdata); 506 507 if (local->ops->hw_scan) { 508 __set_bit(SCAN_HW_SCANNING, &local->scanning); 509 } else if ((req->n_channels == 1) && 510 (req->channels[0] == local->_oper_chandef.chan)) { 511 /* 512 * If we are scanning only on the operating channel 513 * then we do not need to stop normal activities 514 */ 515 unsigned long next_delay; 516 517 __set_bit(SCAN_ONCHANNEL_SCANNING, &local->scanning); 518 519 ieee80211_recalc_idle(local); 520 521 /* Notify driver scan is starting, keep order of operations 522 * same as normal software scan, in case that matters. */ 523 drv_sw_scan_start(local); 524 525 ieee80211_configure_filter(local); /* accept probe-responses */ 526 527 /* We need to ensure power level is at max for scanning. */ 528 ieee80211_hw_config(local, 0); 529 530 if ((req->channels[0]->flags & 531 IEEE80211_CHAN_NO_IR) || 532 !local->scan_req->n_ssids) { 533 next_delay = IEEE80211_PASSIVE_CHANNEL_TIME; 534 } else { 535 ieee80211_scan_state_send_probe(local, &next_delay); 536 next_delay = IEEE80211_CHANNEL_TIME; 537 } 538 539 /* Now, just wait a bit and we are all done! */ 540 ieee80211_queue_delayed_work(&local->hw, &local->scan_work, 541 next_delay); 542 return 0; 543 } else { 544 /* Do normal software scan */ 545 __set_bit(SCAN_SW_SCANNING, &local->scanning); 546 } 547 548 ieee80211_recalc_idle(local); 549 550 if (local->ops->hw_scan) { 551 WARN_ON(!ieee80211_prep_hw_scan(local)); 552 rc = drv_hw_scan(local, sdata, local->hw_scan_req); 553 } else 554 rc = ieee80211_start_sw_scan(local); 555 556 if (rc) { 557 kfree(local->hw_scan_req); 558 local->hw_scan_req = NULL; 559 local->scanning = 0; 560 561 ieee80211_recalc_idle(local); 562 563 local->scan_req = NULL; 564 rcu_assign_pointer(local->scan_sdata, NULL); 565 } 566 567 return rc; 568 } 569 570 static unsigned long 571 ieee80211_scan_get_channel_time(struct ieee80211_channel *chan) 572 { 573 /* 574 * TODO: channel switching also consumes quite some time, 575 * add that delay as well to get a better estimation 576 */ 577 if (chan->flags & IEEE80211_CHAN_NO_IR) 578 return IEEE80211_PASSIVE_CHANNEL_TIME; 579 return IEEE80211_PROBE_DELAY + IEEE80211_CHANNEL_TIME; 580 } 581 582 static void ieee80211_scan_state_decision(struct ieee80211_local *local, 583 unsigned long *next_delay) 584 { 585 bool associated = false; 586 bool tx_empty = true; 587 bool bad_latency; 588 struct ieee80211_sub_if_data *sdata; 589 struct ieee80211_channel *next_chan; 590 enum mac80211_scan_state next_scan_state; 591 592 /* 593 * check if at least one STA interface is associated, 594 * check if at least one STA interface has pending tx frames 595 * and grab the lowest used beacon interval 596 */ 597 mutex_lock(&local->iflist_mtx); 598 list_for_each_entry(sdata, &local->interfaces, list) { 599 if (!ieee80211_sdata_running(sdata)) 600 continue; 601 602 if (sdata->vif.type == NL80211_IFTYPE_STATION) { 603 if (sdata->u.mgd.associated) { 604 associated = true; 605 606 if (!qdisc_all_tx_empty(sdata->dev)) { 607 tx_empty = false; 608 break; 609 } 610 } 611 } 612 } 613 mutex_unlock(&local->iflist_mtx); 614 615 next_chan = local->scan_req->channels[local->scan_channel_idx]; 616 617 /* 618 * we're currently scanning a different channel, let's 619 * see if we can scan another channel without interfering 620 * with the current traffic situation. 621 * 622 * Keep good latency, do not stay off-channel more than 125 ms. 623 */ 624 625 bad_latency = time_after(jiffies + 626 ieee80211_scan_get_channel_time(next_chan), 627 local->leave_oper_channel_time + HZ / 8); 628 629 if (associated && !tx_empty) { 630 if (local->scan_req->flags & NL80211_SCAN_FLAG_LOW_PRIORITY) 631 next_scan_state = SCAN_ABORT; 632 else 633 next_scan_state = SCAN_SUSPEND; 634 } else if (associated && bad_latency) { 635 next_scan_state = SCAN_SUSPEND; 636 } else { 637 next_scan_state = SCAN_SET_CHANNEL; 638 } 639 640 local->next_scan_state = next_scan_state; 641 642 *next_delay = 0; 643 } 644 645 static void ieee80211_scan_state_set_channel(struct ieee80211_local *local, 646 unsigned long *next_delay) 647 { 648 int skip; 649 struct ieee80211_channel *chan; 650 enum nl80211_bss_scan_width oper_scan_width; 651 652 skip = 0; 653 chan = local->scan_req->channels[local->scan_channel_idx]; 654 655 local->scan_chandef.chan = chan; 656 local->scan_chandef.center_freq1 = chan->center_freq; 657 local->scan_chandef.center_freq2 = 0; 658 switch (local->scan_req->scan_width) { 659 case NL80211_BSS_CHAN_WIDTH_5: 660 local->scan_chandef.width = NL80211_CHAN_WIDTH_5; 661 break; 662 case NL80211_BSS_CHAN_WIDTH_10: 663 local->scan_chandef.width = NL80211_CHAN_WIDTH_10; 664 break; 665 case NL80211_BSS_CHAN_WIDTH_20: 666 /* If scanning on oper channel, use whatever channel-type 667 * is currently in use. 668 */ 669 oper_scan_width = cfg80211_chandef_to_scan_width( 670 &local->_oper_chandef); 671 if (chan == local->_oper_chandef.chan && 672 oper_scan_width == local->scan_req->scan_width) 673 local->scan_chandef = local->_oper_chandef; 674 else 675 local->scan_chandef.width = NL80211_CHAN_WIDTH_20_NOHT; 676 break; 677 } 678 679 if (ieee80211_hw_config(local, IEEE80211_CONF_CHANGE_CHANNEL)) 680 skip = 1; 681 682 /* advance state machine to next channel/band */ 683 local->scan_channel_idx++; 684 685 if (skip) { 686 /* if we skip this channel return to the decision state */ 687 local->next_scan_state = SCAN_DECISION; 688 return; 689 } 690 691 /* 692 * Probe delay is used to update the NAV, cf. 11.1.3.2.2 693 * (which unfortunately doesn't say _why_ step a) is done, 694 * but it waits for the probe delay or until a frame is 695 * received - and the received frame would update the NAV). 696 * For now, we do not support waiting until a frame is 697 * received. 698 * 699 * In any case, it is not necessary for a passive scan. 700 */ 701 if (chan->flags & IEEE80211_CHAN_NO_IR || 702 !local->scan_req->n_ssids) { 703 *next_delay = IEEE80211_PASSIVE_CHANNEL_TIME; 704 local->next_scan_state = SCAN_DECISION; 705 return; 706 } 707 708 /* active scan, send probes */ 709 *next_delay = IEEE80211_PROBE_DELAY; 710 local->next_scan_state = SCAN_SEND_PROBE; 711 } 712 713 static void ieee80211_scan_state_suspend(struct ieee80211_local *local, 714 unsigned long *next_delay) 715 { 716 /* switch back to the operating channel */ 717 local->scan_chandef.chan = NULL; 718 ieee80211_hw_config(local, IEEE80211_CONF_CHANGE_CHANNEL); 719 720 /* disable PS */ 721 ieee80211_offchannel_return(local); 722 723 *next_delay = HZ / 5; 724 /* afterwards, resume scan & go to next channel */ 725 local->next_scan_state = SCAN_RESUME; 726 } 727 728 static void ieee80211_scan_state_resume(struct ieee80211_local *local, 729 unsigned long *next_delay) 730 { 731 ieee80211_offchannel_stop_vifs(local); 732 733 if (local->ops->flush) { 734 ieee80211_flush_queues(local, NULL); 735 *next_delay = 0; 736 } else 737 *next_delay = HZ / 10; 738 739 /* remember when we left the operating channel */ 740 local->leave_oper_channel_time = jiffies; 741 742 /* advance to the next channel to be scanned */ 743 local->next_scan_state = SCAN_SET_CHANNEL; 744 } 745 746 void ieee80211_scan_work(struct work_struct *work) 747 { 748 struct ieee80211_local *local = 749 container_of(work, struct ieee80211_local, scan_work.work); 750 struct ieee80211_sub_if_data *sdata; 751 unsigned long next_delay = 0; 752 bool aborted; 753 754 mutex_lock(&local->mtx); 755 756 sdata = rcu_dereference_protected(local->scan_sdata, 757 lockdep_is_held(&local->mtx)); 758 759 /* When scanning on-channel, the first-callback means completed. */ 760 if (test_bit(SCAN_ONCHANNEL_SCANNING, &local->scanning)) { 761 aborted = test_and_clear_bit(SCAN_ABORTED, &local->scanning); 762 goto out_complete; 763 } 764 765 if (test_and_clear_bit(SCAN_COMPLETED, &local->scanning)) { 766 aborted = test_and_clear_bit(SCAN_ABORTED, &local->scanning); 767 goto out_complete; 768 } 769 770 if (!sdata || !local->scan_req) 771 goto out; 772 773 if (local->scan_req && !local->scanning) { 774 struct cfg80211_scan_request *req = local->scan_req; 775 int rc; 776 777 local->scan_req = NULL; 778 rcu_assign_pointer(local->scan_sdata, NULL); 779 780 rc = __ieee80211_start_scan(sdata, req); 781 if (rc) { 782 /* need to complete scan in cfg80211 */ 783 local->scan_req = req; 784 aborted = true; 785 goto out_complete; 786 } else 787 goto out; 788 } 789 790 /* 791 * as long as no delay is required advance immediately 792 * without scheduling a new work 793 */ 794 do { 795 if (!ieee80211_sdata_running(sdata)) { 796 aborted = true; 797 goto out_complete; 798 } 799 800 switch (local->next_scan_state) { 801 case SCAN_DECISION: 802 /* if no more bands/channels left, complete scan */ 803 if (local->scan_channel_idx >= local->scan_req->n_channels) { 804 aborted = false; 805 goto out_complete; 806 } 807 ieee80211_scan_state_decision(local, &next_delay); 808 break; 809 case SCAN_SET_CHANNEL: 810 ieee80211_scan_state_set_channel(local, &next_delay); 811 break; 812 case SCAN_SEND_PROBE: 813 ieee80211_scan_state_send_probe(local, &next_delay); 814 break; 815 case SCAN_SUSPEND: 816 ieee80211_scan_state_suspend(local, &next_delay); 817 break; 818 case SCAN_RESUME: 819 ieee80211_scan_state_resume(local, &next_delay); 820 break; 821 case SCAN_ABORT: 822 aborted = true; 823 goto out_complete; 824 } 825 } while (next_delay == 0); 826 827 ieee80211_queue_delayed_work(&local->hw, &local->scan_work, next_delay); 828 goto out; 829 830 out_complete: 831 __ieee80211_scan_completed(&local->hw, aborted); 832 out: 833 mutex_unlock(&local->mtx); 834 } 835 836 int ieee80211_request_scan(struct ieee80211_sub_if_data *sdata, 837 struct cfg80211_scan_request *req) 838 { 839 int res; 840 841 mutex_lock(&sdata->local->mtx); 842 res = __ieee80211_start_scan(sdata, req); 843 mutex_unlock(&sdata->local->mtx); 844 845 return res; 846 } 847 848 int ieee80211_request_ibss_scan(struct ieee80211_sub_if_data *sdata, 849 const u8 *ssid, u8 ssid_len, 850 struct ieee80211_channel *chan, 851 enum nl80211_bss_scan_width scan_width) 852 { 853 struct ieee80211_local *local = sdata->local; 854 int ret = -EBUSY; 855 enum ieee80211_band band; 856 857 mutex_lock(&local->mtx); 858 859 /* busy scanning */ 860 if (local->scan_req) 861 goto unlock; 862 863 /* fill internal scan request */ 864 if (!chan) { 865 int i, max_n; 866 int n_ch = 0; 867 868 for (band = 0; band < IEEE80211_NUM_BANDS; band++) { 869 if (!local->hw.wiphy->bands[band]) 870 continue; 871 872 max_n = local->hw.wiphy->bands[band]->n_channels; 873 for (i = 0; i < max_n; i++) { 874 struct ieee80211_channel *tmp_ch = 875 &local->hw.wiphy->bands[band]->channels[i]; 876 877 if (tmp_ch->flags & (IEEE80211_CHAN_NO_IR | 878 IEEE80211_CHAN_DISABLED)) 879 continue; 880 881 local->int_scan_req->channels[n_ch] = tmp_ch; 882 n_ch++; 883 } 884 } 885 886 if (WARN_ON_ONCE(n_ch == 0)) 887 goto unlock; 888 889 local->int_scan_req->n_channels = n_ch; 890 } else { 891 if (WARN_ON_ONCE(chan->flags & (IEEE80211_CHAN_NO_IR | 892 IEEE80211_CHAN_DISABLED))) 893 goto unlock; 894 895 local->int_scan_req->channels[0] = chan; 896 local->int_scan_req->n_channels = 1; 897 } 898 899 local->int_scan_req->ssids = &local->scan_ssid; 900 local->int_scan_req->n_ssids = 1; 901 local->int_scan_req->scan_width = scan_width; 902 memcpy(local->int_scan_req->ssids[0].ssid, ssid, IEEE80211_MAX_SSID_LEN); 903 local->int_scan_req->ssids[0].ssid_len = ssid_len; 904 905 ret = __ieee80211_start_scan(sdata, sdata->local->int_scan_req); 906 unlock: 907 mutex_unlock(&local->mtx); 908 return ret; 909 } 910 911 /* 912 * Only call this function when a scan can't be queued -- under RTNL. 913 */ 914 void ieee80211_scan_cancel(struct ieee80211_local *local) 915 { 916 /* 917 * We are canceling software scan, or deferred scan that was not 918 * yet really started (see __ieee80211_start_scan ). 919 * 920 * Regarding hardware scan: 921 * - we can not call __ieee80211_scan_completed() as when 922 * SCAN_HW_SCANNING bit is set this function change 923 * local->hw_scan_req to operate on 5G band, what race with 924 * driver which can use local->hw_scan_req 925 * 926 * - we can not cancel scan_work since driver can schedule it 927 * by ieee80211_scan_completed(..., true) to finish scan 928 * 929 * Hence we only call the cancel_hw_scan() callback, but the low-level 930 * driver is still responsible for calling ieee80211_scan_completed() 931 * after the scan was completed/aborted. 932 */ 933 934 mutex_lock(&local->mtx); 935 if (!local->scan_req) 936 goto out; 937 938 /* 939 * We have a scan running and the driver already reported completion, 940 * but the worker hasn't run yet or is stuck on the mutex - mark it as 941 * cancelled. 942 */ 943 if (test_bit(SCAN_HW_SCANNING, &local->scanning) && 944 test_bit(SCAN_COMPLETED, &local->scanning)) { 945 set_bit(SCAN_HW_CANCELLED, &local->scanning); 946 goto out; 947 } 948 949 if (test_bit(SCAN_HW_SCANNING, &local->scanning)) { 950 /* 951 * Make sure that __ieee80211_scan_completed doesn't trigger a 952 * scan on another band. 953 */ 954 set_bit(SCAN_HW_CANCELLED, &local->scanning); 955 if (local->ops->cancel_hw_scan) 956 drv_cancel_hw_scan(local, 957 rcu_dereference_protected(local->scan_sdata, 958 lockdep_is_held(&local->mtx))); 959 goto out; 960 } 961 962 /* 963 * If the work is currently running, it must be blocked on 964 * the mutex, but we'll set scan_sdata = NULL and it'll 965 * simply exit once it acquires the mutex. 966 */ 967 cancel_delayed_work(&local->scan_work); 968 /* and clean up */ 969 __ieee80211_scan_completed(&local->hw, true); 970 out: 971 mutex_unlock(&local->mtx); 972 } 973 974 int __ieee80211_request_sched_scan_start(struct ieee80211_sub_if_data *sdata, 975 struct cfg80211_sched_scan_request *req) 976 { 977 struct ieee80211_local *local = sdata->local; 978 struct ieee80211_sched_scan_ies sched_scan_ies = {}; 979 struct cfg80211_chan_def chandef; 980 int ret, i, iebufsz; 981 982 iebufsz = 2 + IEEE80211_MAX_SSID_LEN + 983 local->scan_ies_len + req->ie_len; 984 985 lockdep_assert_held(&local->mtx); 986 987 if (!local->ops->sched_scan_start) 988 return -ENOTSUPP; 989 990 for (i = 0; i < IEEE80211_NUM_BANDS; i++) { 991 if (!local->hw.wiphy->bands[i]) 992 continue; 993 994 sched_scan_ies.ie[i] = kzalloc(iebufsz, GFP_KERNEL); 995 if (!sched_scan_ies.ie[i]) { 996 ret = -ENOMEM; 997 goto out_free; 998 } 999 1000 ieee80211_prepare_scan_chandef(&chandef, req->scan_width); 1001 1002 sched_scan_ies.len[i] = 1003 ieee80211_build_preq_ies(local, sched_scan_ies.ie[i], 1004 iebufsz, req->ie, req->ie_len, 1005 i, (u32) -1, &chandef); 1006 } 1007 1008 ret = drv_sched_scan_start(local, sdata, req, &sched_scan_ies); 1009 if (ret == 0) { 1010 rcu_assign_pointer(local->sched_scan_sdata, sdata); 1011 local->sched_scan_req = req; 1012 } 1013 1014 out_free: 1015 while (i > 0) 1016 kfree(sched_scan_ies.ie[--i]); 1017 1018 if (ret) { 1019 /* Clean in case of failure after HW restart or upon resume. */ 1020 rcu_assign_pointer(local->sched_scan_sdata, NULL); 1021 local->sched_scan_req = NULL; 1022 } 1023 1024 return ret; 1025 } 1026 1027 int ieee80211_request_sched_scan_start(struct ieee80211_sub_if_data *sdata, 1028 struct cfg80211_sched_scan_request *req) 1029 { 1030 struct ieee80211_local *local = sdata->local; 1031 int ret; 1032 1033 mutex_lock(&local->mtx); 1034 1035 if (rcu_access_pointer(local->sched_scan_sdata)) { 1036 mutex_unlock(&local->mtx); 1037 return -EBUSY; 1038 } 1039 1040 ret = __ieee80211_request_sched_scan_start(sdata, req); 1041 1042 mutex_unlock(&local->mtx); 1043 return ret; 1044 } 1045 1046 int ieee80211_request_sched_scan_stop(struct ieee80211_sub_if_data *sdata) 1047 { 1048 struct ieee80211_local *local = sdata->local; 1049 int ret = 0; 1050 1051 mutex_lock(&local->mtx); 1052 1053 if (!local->ops->sched_scan_stop) { 1054 ret = -ENOTSUPP; 1055 goto out; 1056 } 1057 1058 /* We don't want to restart sched scan anymore. */ 1059 local->sched_scan_req = NULL; 1060 1061 if (rcu_access_pointer(local->sched_scan_sdata)) 1062 drv_sched_scan_stop(local, sdata); 1063 1064 out: 1065 mutex_unlock(&local->mtx); 1066 1067 return ret; 1068 } 1069 1070 void ieee80211_sched_scan_results(struct ieee80211_hw *hw) 1071 { 1072 struct ieee80211_local *local = hw_to_local(hw); 1073 1074 trace_api_sched_scan_results(local); 1075 1076 cfg80211_sched_scan_results(hw->wiphy); 1077 } 1078 EXPORT_SYMBOL(ieee80211_sched_scan_results); 1079 1080 void ieee80211_sched_scan_stopped_work(struct work_struct *work) 1081 { 1082 struct ieee80211_local *local = 1083 container_of(work, struct ieee80211_local, 1084 sched_scan_stopped_work); 1085 1086 mutex_lock(&local->mtx); 1087 1088 if (!rcu_access_pointer(local->sched_scan_sdata)) { 1089 mutex_unlock(&local->mtx); 1090 return; 1091 } 1092 1093 rcu_assign_pointer(local->sched_scan_sdata, NULL); 1094 1095 /* If sched scan was aborted by the driver. */ 1096 local->sched_scan_req = NULL; 1097 1098 mutex_unlock(&local->mtx); 1099 1100 cfg80211_sched_scan_stopped(local->hw.wiphy); 1101 } 1102 1103 void ieee80211_sched_scan_stopped(struct ieee80211_hw *hw) 1104 { 1105 struct ieee80211_local *local = hw_to_local(hw); 1106 1107 trace_api_sched_scan_stopped(local); 1108 1109 schedule_work(&local->sched_scan_stopped_work); 1110 } 1111 EXPORT_SYMBOL(ieee80211_sched_scan_stopped); 1112