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 bool was_hw_scan) 276 { 277 struct ieee80211_local *local = hw_to_local(hw); 278 279 lockdep_assert_held(&local->mtx); 280 281 /* 282 * It's ok to abort a not-yet-running scan (that 283 * we have one at all will be verified by checking 284 * local->scan_req next), but not to complete it 285 * successfully. 286 */ 287 if (WARN_ON(!local->scanning && !aborted)) 288 aborted = true; 289 290 if (WARN_ON(!local->scan_req)) 291 return; 292 293 if (was_hw_scan && !aborted && ieee80211_prep_hw_scan(local)) { 294 int rc; 295 296 rc = drv_hw_scan(local, 297 rcu_dereference_protected(local->scan_sdata, 298 lockdep_is_held(&local->mtx)), 299 local->hw_scan_req); 300 301 if (rc == 0) 302 return; 303 } 304 305 kfree(local->hw_scan_req); 306 local->hw_scan_req = NULL; 307 308 if (local->scan_req != local->int_scan_req) 309 cfg80211_scan_done(local->scan_req, aborted); 310 local->scan_req = NULL; 311 rcu_assign_pointer(local->scan_sdata, NULL); 312 313 local->scanning = 0; 314 local->scan_chandef.chan = NULL; 315 316 /* Set power back to normal operating levels. */ 317 ieee80211_hw_config(local, 0); 318 319 if (!was_hw_scan) { 320 ieee80211_configure_filter(local); 321 drv_sw_scan_complete(local); 322 ieee80211_offchannel_return(local); 323 } 324 325 ieee80211_recalc_idle(local); 326 327 ieee80211_mlme_notify_scan_completed(local); 328 ieee80211_ibss_notify_scan_completed(local); 329 ieee80211_mesh_notify_scan_completed(local); 330 ieee80211_start_next_roc(local); 331 } 332 333 void ieee80211_scan_completed(struct ieee80211_hw *hw, bool aborted) 334 { 335 struct ieee80211_local *local = hw_to_local(hw); 336 337 trace_api_scan_completed(local, aborted); 338 339 set_bit(SCAN_COMPLETED, &local->scanning); 340 if (aborted) 341 set_bit(SCAN_ABORTED, &local->scanning); 342 ieee80211_queue_delayed_work(&local->hw, &local->scan_work, 0); 343 } 344 EXPORT_SYMBOL(ieee80211_scan_completed); 345 346 static int ieee80211_start_sw_scan(struct ieee80211_local *local) 347 { 348 /* Software scan is not supported in multi-channel cases */ 349 if (local->use_chanctx) 350 return -EOPNOTSUPP; 351 352 /* 353 * Hardware/driver doesn't support hw_scan, so use software 354 * scanning instead. First send a nullfunc frame with power save 355 * bit on so that AP will buffer the frames for us while we are not 356 * listening, then send probe requests to each channel and wait for 357 * the responses. After all channels are scanned, tune back to the 358 * original channel and send a nullfunc frame with power save bit 359 * off to trigger the AP to send us all the buffered frames. 360 * 361 * Note that while local->sw_scanning is true everything else but 362 * nullfunc frames and probe requests will be dropped in 363 * ieee80211_tx_h_check_assoc(). 364 */ 365 drv_sw_scan_start(local); 366 367 local->leave_oper_channel_time = jiffies; 368 local->next_scan_state = SCAN_DECISION; 369 local->scan_channel_idx = 0; 370 371 ieee80211_offchannel_stop_vifs(local); 372 373 /* ensure nullfunc is transmitted before leaving operating channel */ 374 ieee80211_flush_queues(local, NULL); 375 376 ieee80211_configure_filter(local); 377 378 /* We need to set power level at maximum rate for scanning. */ 379 ieee80211_hw_config(local, 0); 380 381 ieee80211_queue_delayed_work(&local->hw, 382 &local->scan_work, 0); 383 384 return 0; 385 } 386 387 static bool ieee80211_can_scan(struct ieee80211_local *local, 388 struct ieee80211_sub_if_data *sdata) 389 { 390 if (local->radar_detect_enabled) 391 return false; 392 393 if (!list_empty(&local->roc_list)) 394 return false; 395 396 if (sdata->vif.type == NL80211_IFTYPE_STATION && 397 sdata->u.mgd.flags & (IEEE80211_STA_BEACON_POLL | 398 IEEE80211_STA_CONNECTION_POLL)) 399 return false; 400 401 return true; 402 } 403 404 void ieee80211_run_deferred_scan(struct ieee80211_local *local) 405 { 406 lockdep_assert_held(&local->mtx); 407 408 if (!local->scan_req || local->scanning) 409 return; 410 411 if (!ieee80211_can_scan(local, 412 rcu_dereference_protected( 413 local->scan_sdata, 414 lockdep_is_held(&local->mtx)))) 415 return; 416 417 ieee80211_queue_delayed_work(&local->hw, &local->scan_work, 418 round_jiffies_relative(0)); 419 } 420 421 static void ieee80211_scan_state_send_probe(struct ieee80211_local *local, 422 unsigned long *next_delay) 423 { 424 int i; 425 struct ieee80211_sub_if_data *sdata; 426 enum ieee80211_band band = local->hw.conf.chandef.chan->band; 427 u32 tx_flags; 428 429 tx_flags = IEEE80211_TX_INTFL_OFFCHAN_TX_OK; 430 if (local->scan_req->no_cck) 431 tx_flags |= IEEE80211_TX_CTL_NO_CCK_RATE; 432 433 sdata = rcu_dereference_protected(local->scan_sdata, 434 lockdep_is_held(&local->mtx)); 435 436 for (i = 0; i < local->scan_req->n_ssids; i++) 437 ieee80211_send_probe_req( 438 sdata, NULL, 439 local->scan_req->ssids[i].ssid, 440 local->scan_req->ssids[i].ssid_len, 441 local->scan_req->ie, local->scan_req->ie_len, 442 local->scan_req->rates[band], false, 443 tx_flags, local->hw.conf.chandef.chan, true); 444 445 /* 446 * After sending probe requests, wait for probe responses 447 * on the channel. 448 */ 449 *next_delay = IEEE80211_CHANNEL_TIME; 450 local->next_scan_state = SCAN_DECISION; 451 } 452 453 static int __ieee80211_start_scan(struct ieee80211_sub_if_data *sdata, 454 struct cfg80211_scan_request *req) 455 { 456 struct ieee80211_local *local = sdata->local; 457 int rc; 458 459 lockdep_assert_held(&local->mtx); 460 461 if (local->scan_req) 462 return -EBUSY; 463 464 if (!ieee80211_can_scan(local, sdata)) { 465 /* wait for the work to finish/time out */ 466 local->scan_req = req; 467 rcu_assign_pointer(local->scan_sdata, sdata); 468 return 0; 469 } 470 471 if (local->ops->hw_scan) { 472 u8 *ies; 473 474 local->hw_scan_ies_bufsize = 2 + IEEE80211_MAX_SSID_LEN + 475 local->scan_ies_len + 476 req->ie_len; 477 local->hw_scan_req = kmalloc( 478 sizeof(*local->hw_scan_req) + 479 req->n_channels * sizeof(req->channels[0]) + 480 local->hw_scan_ies_bufsize, GFP_KERNEL); 481 if (!local->hw_scan_req) 482 return -ENOMEM; 483 484 local->hw_scan_req->ssids = req->ssids; 485 local->hw_scan_req->n_ssids = req->n_ssids; 486 ies = (u8 *)local->hw_scan_req + 487 sizeof(*local->hw_scan_req) + 488 req->n_channels * sizeof(req->channels[0]); 489 local->hw_scan_req->ie = ies; 490 local->hw_scan_req->flags = req->flags; 491 492 local->hw_scan_band = 0; 493 494 /* 495 * After allocating local->hw_scan_req, we must 496 * go through until ieee80211_prep_hw_scan(), so 497 * anything that might be changed here and leave 498 * this function early must not go after this 499 * allocation. 500 */ 501 } 502 503 local->scan_req = req; 504 rcu_assign_pointer(local->scan_sdata, sdata); 505 506 if (local->ops->hw_scan) { 507 __set_bit(SCAN_HW_SCANNING, &local->scanning); 508 } else if ((req->n_channels == 1) && 509 (req->channels[0] == local->_oper_chandef.chan)) { 510 /* 511 * If we are scanning only on the operating channel 512 * then we do not need to stop normal activities 513 */ 514 unsigned long next_delay; 515 516 __set_bit(SCAN_ONCHANNEL_SCANNING, &local->scanning); 517 518 ieee80211_recalc_idle(local); 519 520 /* Notify driver scan is starting, keep order of operations 521 * same as normal software scan, in case that matters. */ 522 drv_sw_scan_start(local); 523 524 ieee80211_configure_filter(local); /* accept probe-responses */ 525 526 /* We need to ensure power level is at max for scanning. */ 527 ieee80211_hw_config(local, 0); 528 529 if ((req->channels[0]->flags & 530 IEEE80211_CHAN_PASSIVE_SCAN) || 531 !local->scan_req->n_ssids) { 532 next_delay = IEEE80211_PASSIVE_CHANNEL_TIME; 533 } else { 534 ieee80211_scan_state_send_probe(local, &next_delay); 535 next_delay = IEEE80211_CHANNEL_TIME; 536 } 537 538 /* Now, just wait a bit and we are all done! */ 539 ieee80211_queue_delayed_work(&local->hw, &local->scan_work, 540 next_delay); 541 return 0; 542 } else { 543 /* Do normal software scan */ 544 __set_bit(SCAN_SW_SCANNING, &local->scanning); 545 } 546 547 ieee80211_recalc_idle(local); 548 549 if (local->ops->hw_scan) { 550 WARN_ON(!ieee80211_prep_hw_scan(local)); 551 rc = drv_hw_scan(local, sdata, local->hw_scan_req); 552 } else 553 rc = ieee80211_start_sw_scan(local); 554 555 if (rc) { 556 kfree(local->hw_scan_req); 557 local->hw_scan_req = NULL; 558 local->scanning = 0; 559 560 ieee80211_recalc_idle(local); 561 562 local->scan_req = NULL; 563 rcu_assign_pointer(local->scan_sdata, NULL); 564 } 565 566 return rc; 567 } 568 569 static unsigned long 570 ieee80211_scan_get_channel_time(struct ieee80211_channel *chan) 571 { 572 /* 573 * TODO: channel switching also consumes quite some time, 574 * add that delay as well to get a better estimation 575 */ 576 if (chan->flags & IEEE80211_CHAN_PASSIVE_SCAN) 577 return IEEE80211_PASSIVE_CHANNEL_TIME; 578 return IEEE80211_PROBE_DELAY + IEEE80211_CHANNEL_TIME; 579 } 580 581 static void ieee80211_scan_state_decision(struct ieee80211_local *local, 582 unsigned long *next_delay) 583 { 584 bool associated = false; 585 bool tx_empty = true; 586 bool bad_latency; 587 struct ieee80211_sub_if_data *sdata; 588 struct ieee80211_channel *next_chan; 589 enum mac80211_scan_state next_scan_state; 590 591 /* 592 * check if at least one STA interface is associated, 593 * check if at least one STA interface has pending tx frames 594 * and grab the lowest used beacon interval 595 */ 596 mutex_lock(&local->iflist_mtx); 597 list_for_each_entry(sdata, &local->interfaces, list) { 598 if (!ieee80211_sdata_running(sdata)) 599 continue; 600 601 if (sdata->vif.type == NL80211_IFTYPE_STATION) { 602 if (sdata->u.mgd.associated) { 603 associated = true; 604 605 if (!qdisc_all_tx_empty(sdata->dev)) { 606 tx_empty = false; 607 break; 608 } 609 } 610 } 611 } 612 mutex_unlock(&local->iflist_mtx); 613 614 next_chan = local->scan_req->channels[local->scan_channel_idx]; 615 616 /* 617 * we're currently scanning a different channel, let's 618 * see if we can scan another channel without interfering 619 * with the current traffic situation. 620 * 621 * Keep good latency, do not stay off-channel more than 125 ms. 622 */ 623 624 bad_latency = time_after(jiffies + 625 ieee80211_scan_get_channel_time(next_chan), 626 local->leave_oper_channel_time + HZ / 8); 627 628 if (associated && !tx_empty) { 629 if (local->scan_req->flags & NL80211_SCAN_FLAG_LOW_PRIORITY) 630 next_scan_state = SCAN_ABORT; 631 else 632 next_scan_state = SCAN_SUSPEND; 633 } else if (associated && bad_latency) { 634 next_scan_state = SCAN_SUSPEND; 635 } else { 636 next_scan_state = SCAN_SET_CHANNEL; 637 } 638 639 local->next_scan_state = next_scan_state; 640 641 *next_delay = 0; 642 } 643 644 static void ieee80211_scan_state_set_channel(struct ieee80211_local *local, 645 unsigned long *next_delay) 646 { 647 int skip; 648 struct ieee80211_channel *chan; 649 enum nl80211_bss_scan_width oper_scan_width; 650 651 skip = 0; 652 chan = local->scan_req->channels[local->scan_channel_idx]; 653 654 local->scan_chandef.chan = chan; 655 local->scan_chandef.center_freq1 = chan->center_freq; 656 local->scan_chandef.center_freq2 = 0; 657 switch (local->scan_req->scan_width) { 658 case NL80211_BSS_CHAN_WIDTH_5: 659 local->scan_chandef.width = NL80211_CHAN_WIDTH_5; 660 break; 661 case NL80211_BSS_CHAN_WIDTH_10: 662 local->scan_chandef.width = NL80211_CHAN_WIDTH_10; 663 break; 664 case NL80211_BSS_CHAN_WIDTH_20: 665 /* If scanning on oper channel, use whatever channel-type 666 * is currently in use. 667 */ 668 oper_scan_width = cfg80211_chandef_to_scan_width( 669 &local->_oper_chandef); 670 if (chan == local->_oper_chandef.chan && 671 oper_scan_width == local->scan_req->scan_width) 672 local->scan_chandef = local->_oper_chandef; 673 else 674 local->scan_chandef.width = NL80211_CHAN_WIDTH_20_NOHT; 675 break; 676 } 677 678 if (ieee80211_hw_config(local, IEEE80211_CONF_CHANGE_CHANNEL)) 679 skip = 1; 680 681 /* advance state machine to next channel/band */ 682 local->scan_channel_idx++; 683 684 if (skip) { 685 /* if we skip this channel return to the decision state */ 686 local->next_scan_state = SCAN_DECISION; 687 return; 688 } 689 690 /* 691 * Probe delay is used to update the NAV, cf. 11.1.3.2.2 692 * (which unfortunately doesn't say _why_ step a) is done, 693 * but it waits for the probe delay or until a frame is 694 * received - and the received frame would update the NAV). 695 * For now, we do not support waiting until a frame is 696 * received. 697 * 698 * In any case, it is not necessary for a passive scan. 699 */ 700 if (chan->flags & IEEE80211_CHAN_PASSIVE_SCAN || 701 !local->scan_req->n_ssids) { 702 *next_delay = IEEE80211_PASSIVE_CHANNEL_TIME; 703 local->next_scan_state = SCAN_DECISION; 704 return; 705 } 706 707 /* active scan, send probes */ 708 *next_delay = IEEE80211_PROBE_DELAY; 709 local->next_scan_state = SCAN_SEND_PROBE; 710 } 711 712 static void ieee80211_scan_state_suspend(struct ieee80211_local *local, 713 unsigned long *next_delay) 714 { 715 /* switch back to the operating channel */ 716 local->scan_chandef.chan = NULL; 717 ieee80211_hw_config(local, IEEE80211_CONF_CHANGE_CHANNEL); 718 719 /* disable PS */ 720 ieee80211_offchannel_return(local); 721 722 *next_delay = HZ / 5; 723 /* afterwards, resume scan & go to next channel */ 724 local->next_scan_state = SCAN_RESUME; 725 } 726 727 static void ieee80211_scan_state_resume(struct ieee80211_local *local, 728 unsigned long *next_delay) 729 { 730 ieee80211_offchannel_stop_vifs(local); 731 732 if (local->ops->flush) { 733 ieee80211_flush_queues(local, NULL); 734 *next_delay = 0; 735 } else 736 *next_delay = HZ / 10; 737 738 /* remember when we left the operating channel */ 739 local->leave_oper_channel_time = jiffies; 740 741 /* advance to the next channel to be scanned */ 742 local->next_scan_state = SCAN_SET_CHANNEL; 743 } 744 745 void ieee80211_scan_work(struct work_struct *work) 746 { 747 struct ieee80211_local *local = 748 container_of(work, struct ieee80211_local, scan_work.work); 749 struct ieee80211_sub_if_data *sdata; 750 unsigned long next_delay = 0; 751 bool aborted, hw_scan; 752 753 mutex_lock(&local->mtx); 754 755 sdata = rcu_dereference_protected(local->scan_sdata, 756 lockdep_is_held(&local->mtx)); 757 758 /* When scanning on-channel, the first-callback means completed. */ 759 if (test_bit(SCAN_ONCHANNEL_SCANNING, &local->scanning)) { 760 aborted = test_and_clear_bit(SCAN_ABORTED, &local->scanning); 761 goto out_complete; 762 } 763 764 if (test_and_clear_bit(SCAN_COMPLETED, &local->scanning)) { 765 aborted = test_and_clear_bit(SCAN_ABORTED, &local->scanning); 766 goto out_complete; 767 } 768 769 if (!sdata || !local->scan_req) 770 goto out; 771 772 if (local->scan_req && !local->scanning) { 773 struct cfg80211_scan_request *req = local->scan_req; 774 int rc; 775 776 local->scan_req = NULL; 777 rcu_assign_pointer(local->scan_sdata, NULL); 778 779 rc = __ieee80211_start_scan(sdata, req); 780 if (rc) { 781 /* need to complete scan in cfg80211 */ 782 local->scan_req = req; 783 aborted = true; 784 goto out_complete; 785 } else 786 goto out; 787 } 788 789 /* 790 * Avoid re-scheduling when the sdata is going away. 791 */ 792 if (!ieee80211_sdata_running(sdata)) { 793 aborted = true; 794 goto out_complete; 795 } 796 797 /* 798 * as long as no delay is required advance immediately 799 * without scheduling a new work 800 */ 801 do { 802 if (!ieee80211_sdata_running(sdata)) { 803 aborted = true; 804 goto out_complete; 805 } 806 807 switch (local->next_scan_state) { 808 case SCAN_DECISION: 809 /* if no more bands/channels left, complete scan */ 810 if (local->scan_channel_idx >= local->scan_req->n_channels) { 811 aborted = false; 812 goto out_complete; 813 } 814 ieee80211_scan_state_decision(local, &next_delay); 815 break; 816 case SCAN_SET_CHANNEL: 817 ieee80211_scan_state_set_channel(local, &next_delay); 818 break; 819 case SCAN_SEND_PROBE: 820 ieee80211_scan_state_send_probe(local, &next_delay); 821 break; 822 case SCAN_SUSPEND: 823 ieee80211_scan_state_suspend(local, &next_delay); 824 break; 825 case SCAN_RESUME: 826 ieee80211_scan_state_resume(local, &next_delay); 827 break; 828 case SCAN_ABORT: 829 aborted = true; 830 goto out_complete; 831 } 832 } while (next_delay == 0); 833 834 ieee80211_queue_delayed_work(&local->hw, &local->scan_work, next_delay); 835 goto out; 836 837 out_complete: 838 hw_scan = test_bit(SCAN_HW_SCANNING, &local->scanning); 839 __ieee80211_scan_completed(&local->hw, aborted, hw_scan); 840 out: 841 mutex_unlock(&local->mtx); 842 } 843 844 int ieee80211_request_scan(struct ieee80211_sub_if_data *sdata, 845 struct cfg80211_scan_request *req) 846 { 847 int res; 848 849 mutex_lock(&sdata->local->mtx); 850 res = __ieee80211_start_scan(sdata, req); 851 mutex_unlock(&sdata->local->mtx); 852 853 return res; 854 } 855 856 int ieee80211_request_ibss_scan(struct ieee80211_sub_if_data *sdata, 857 const u8 *ssid, u8 ssid_len, 858 struct ieee80211_channel *chan, 859 enum nl80211_bss_scan_width scan_width) 860 { 861 struct ieee80211_local *local = sdata->local; 862 int ret = -EBUSY; 863 enum ieee80211_band band; 864 865 mutex_lock(&local->mtx); 866 867 /* busy scanning */ 868 if (local->scan_req) 869 goto unlock; 870 871 /* fill internal scan request */ 872 if (!chan) { 873 int i, max_n; 874 int n_ch = 0; 875 876 for (band = 0; band < IEEE80211_NUM_BANDS; band++) { 877 if (!local->hw.wiphy->bands[band]) 878 continue; 879 880 max_n = local->hw.wiphy->bands[band]->n_channels; 881 for (i = 0; i < max_n; i++) { 882 struct ieee80211_channel *tmp_ch = 883 &local->hw.wiphy->bands[band]->channels[i]; 884 885 if (tmp_ch->flags & (IEEE80211_CHAN_NO_IBSS | 886 IEEE80211_CHAN_DISABLED)) 887 continue; 888 889 local->int_scan_req->channels[n_ch] = tmp_ch; 890 n_ch++; 891 } 892 } 893 894 if (WARN_ON_ONCE(n_ch == 0)) 895 goto unlock; 896 897 local->int_scan_req->n_channels = n_ch; 898 } else { 899 if (WARN_ON_ONCE(chan->flags & (IEEE80211_CHAN_NO_IBSS | 900 IEEE80211_CHAN_DISABLED))) 901 goto unlock; 902 903 local->int_scan_req->channels[0] = chan; 904 local->int_scan_req->n_channels = 1; 905 } 906 907 local->int_scan_req->ssids = &local->scan_ssid; 908 local->int_scan_req->n_ssids = 1; 909 local->int_scan_req->scan_width = scan_width; 910 memcpy(local->int_scan_req->ssids[0].ssid, ssid, IEEE80211_MAX_SSID_LEN); 911 local->int_scan_req->ssids[0].ssid_len = ssid_len; 912 913 ret = __ieee80211_start_scan(sdata, sdata->local->int_scan_req); 914 unlock: 915 mutex_unlock(&local->mtx); 916 return ret; 917 } 918 919 /* 920 * Only call this function when a scan can't be queued -- under RTNL. 921 */ 922 void ieee80211_scan_cancel(struct ieee80211_local *local) 923 { 924 /* 925 * We are canceling software scan, or deferred scan that was not 926 * yet really started (see __ieee80211_start_scan ). 927 * 928 * Regarding hardware scan: 929 * - we can not call __ieee80211_scan_completed() as when 930 * SCAN_HW_SCANNING bit is set this function change 931 * local->hw_scan_req to operate on 5G band, what race with 932 * driver which can use local->hw_scan_req 933 * 934 * - we can not cancel scan_work since driver can schedule it 935 * by ieee80211_scan_completed(..., true) to finish scan 936 * 937 * Hence we only call the cancel_hw_scan() callback, but the low-level 938 * driver is still responsible for calling ieee80211_scan_completed() 939 * after the scan was completed/aborted. 940 */ 941 942 mutex_lock(&local->mtx); 943 if (!local->scan_req) 944 goto out; 945 946 /* 947 * We have a scan running and the driver already reported completion, 948 * but the worker hasn't run yet or is stuck on the mutex - mark it as 949 * cancelled. 950 */ 951 if (test_bit(SCAN_HW_SCANNING, &local->scanning) && 952 test_bit(SCAN_COMPLETED, &local->scanning)) { 953 set_bit(SCAN_HW_CANCELLED, &local->scanning); 954 goto out; 955 } 956 957 if (test_bit(SCAN_HW_SCANNING, &local->scanning)) { 958 /* 959 * Make sure that __ieee80211_scan_completed doesn't trigger a 960 * scan on another band. 961 */ 962 set_bit(SCAN_HW_CANCELLED, &local->scanning); 963 if (local->ops->cancel_hw_scan) 964 drv_cancel_hw_scan(local, 965 rcu_dereference_protected(local->scan_sdata, 966 lockdep_is_held(&local->mtx))); 967 goto out; 968 } 969 970 /* 971 * If the work is currently running, it must be blocked on 972 * the mutex, but we'll set scan_sdata = NULL and it'll 973 * simply exit once it acquires the mutex. 974 */ 975 cancel_delayed_work(&local->scan_work); 976 /* and clean up */ 977 __ieee80211_scan_completed(&local->hw, true, false); 978 out: 979 mutex_unlock(&local->mtx); 980 } 981 982 int ieee80211_request_sched_scan_start(struct ieee80211_sub_if_data *sdata, 983 struct cfg80211_sched_scan_request *req) 984 { 985 struct ieee80211_local *local = sdata->local; 986 struct ieee80211_sched_scan_ies sched_scan_ies = {}; 987 struct cfg80211_chan_def chandef; 988 int ret, i, iebufsz; 989 990 iebufsz = 2 + IEEE80211_MAX_SSID_LEN + 991 local->scan_ies_len + req->ie_len; 992 993 mutex_lock(&local->mtx); 994 995 if (rcu_access_pointer(local->sched_scan_sdata)) { 996 ret = -EBUSY; 997 goto out; 998 } 999 1000 if (!local->ops->sched_scan_start) { 1001 ret = -ENOTSUPP; 1002 goto out; 1003 } 1004 1005 for (i = 0; i < IEEE80211_NUM_BANDS; i++) { 1006 if (!local->hw.wiphy->bands[i]) 1007 continue; 1008 1009 sched_scan_ies.ie[i] = kzalloc(iebufsz, GFP_KERNEL); 1010 if (!sched_scan_ies.ie[i]) { 1011 ret = -ENOMEM; 1012 goto out_free; 1013 } 1014 1015 ieee80211_prepare_scan_chandef(&chandef, req->scan_width); 1016 1017 sched_scan_ies.len[i] = 1018 ieee80211_build_preq_ies(local, sched_scan_ies.ie[i], 1019 iebufsz, req->ie, req->ie_len, 1020 i, (u32) -1, &chandef); 1021 } 1022 1023 ret = drv_sched_scan_start(local, sdata, req, &sched_scan_ies); 1024 if (ret == 0) 1025 rcu_assign_pointer(local->sched_scan_sdata, sdata); 1026 1027 out_free: 1028 while (i > 0) 1029 kfree(sched_scan_ies.ie[--i]); 1030 out: 1031 mutex_unlock(&local->mtx); 1032 return ret; 1033 } 1034 1035 int ieee80211_request_sched_scan_stop(struct ieee80211_sub_if_data *sdata) 1036 { 1037 struct ieee80211_local *local = sdata->local; 1038 int ret = 0; 1039 1040 mutex_lock(&local->mtx); 1041 1042 if (!local->ops->sched_scan_stop) { 1043 ret = -ENOTSUPP; 1044 goto out; 1045 } 1046 1047 if (rcu_access_pointer(local->sched_scan_sdata)) 1048 drv_sched_scan_stop(local, sdata); 1049 1050 out: 1051 mutex_unlock(&local->mtx); 1052 1053 return ret; 1054 } 1055 1056 void ieee80211_sched_scan_results(struct ieee80211_hw *hw) 1057 { 1058 struct ieee80211_local *local = hw_to_local(hw); 1059 1060 trace_api_sched_scan_results(local); 1061 1062 cfg80211_sched_scan_results(hw->wiphy); 1063 } 1064 EXPORT_SYMBOL(ieee80211_sched_scan_results); 1065 1066 void ieee80211_sched_scan_stopped_work(struct work_struct *work) 1067 { 1068 struct ieee80211_local *local = 1069 container_of(work, struct ieee80211_local, 1070 sched_scan_stopped_work); 1071 1072 mutex_lock(&local->mtx); 1073 1074 if (!rcu_access_pointer(local->sched_scan_sdata)) { 1075 mutex_unlock(&local->mtx); 1076 return; 1077 } 1078 1079 rcu_assign_pointer(local->sched_scan_sdata, NULL); 1080 1081 mutex_unlock(&local->mtx); 1082 1083 cfg80211_sched_scan_stopped(local->hw.wiphy); 1084 } 1085 1086 void ieee80211_sched_scan_stopped(struct ieee80211_hw *hw) 1087 { 1088 struct ieee80211_local *local = hw_to_local(hw); 1089 1090 trace_api_sched_scan_stopped(local); 1091 1092 ieee80211_queue_work(&local->hw, &local->sched_scan_stopped_work); 1093 } 1094 EXPORT_SYMBOL(ieee80211_sched_scan_stopped); 1095