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 * Copyright 2013-2015 Intel Mobile Communications GmbH 10 * Copyright 2016-2017 Intel Deutschland GmbH 11 * 12 * This program is free software; you can redistribute it and/or modify 13 * it under the terms of the GNU General Public License version 2 as 14 * published by the Free Software Foundation. 15 */ 16 17 #include <linux/if_arp.h> 18 #include <linux/etherdevice.h> 19 #include <linux/rtnetlink.h> 20 #include <net/sch_generic.h> 21 #include <linux/slab.h> 22 #include <linux/export.h> 23 #include <net/mac80211.h> 24 25 #include "ieee80211_i.h" 26 #include "driver-ops.h" 27 #include "mesh.h" 28 29 #define IEEE80211_PROBE_DELAY (HZ / 33) 30 #define IEEE80211_CHANNEL_TIME (HZ / 33) 31 #define IEEE80211_PASSIVE_CHANNEL_TIME (HZ / 9) 32 33 void ieee80211_rx_bss_put(struct ieee80211_local *local, 34 struct ieee80211_bss *bss) 35 { 36 if (!bss) 37 return; 38 cfg80211_put_bss(local->hw.wiphy, 39 container_of((void *)bss, struct cfg80211_bss, priv)); 40 } 41 42 static bool is_uapsd_supported(struct ieee802_11_elems *elems) 43 { 44 u8 qos_info; 45 46 if (elems->wmm_info && elems->wmm_info_len == 7 47 && elems->wmm_info[5] == 1) 48 qos_info = elems->wmm_info[6]; 49 else if (elems->wmm_param && elems->wmm_param_len == 24 50 && elems->wmm_param[5] == 1) 51 qos_info = elems->wmm_param[6]; 52 else 53 /* no valid wmm information or parameter element found */ 54 return false; 55 56 return qos_info & IEEE80211_WMM_IE_AP_QOSINFO_UAPSD; 57 } 58 59 struct ieee80211_bss * 60 ieee80211_bss_info_update(struct ieee80211_local *local, 61 struct ieee80211_rx_status *rx_status, 62 struct ieee80211_mgmt *mgmt, size_t len, 63 struct ieee802_11_elems *elems, 64 struct ieee80211_channel *channel) 65 { 66 bool beacon = ieee80211_is_beacon(mgmt->frame_control); 67 struct cfg80211_bss *cbss; 68 struct ieee80211_bss *bss; 69 int clen, srlen; 70 struct cfg80211_inform_bss bss_meta = { 71 .boottime_ns = rx_status->boottime_ns, 72 }; 73 bool signal_valid; 74 struct ieee80211_sub_if_data *scan_sdata; 75 76 if (ieee80211_hw_check(&local->hw, SIGNAL_DBM)) 77 bss_meta.signal = rx_status->signal * 100; 78 else if (ieee80211_hw_check(&local->hw, SIGNAL_UNSPEC)) 79 bss_meta.signal = (rx_status->signal * 100) / local->hw.max_signal; 80 81 bss_meta.scan_width = NL80211_BSS_CHAN_WIDTH_20; 82 if (rx_status->bw == RATE_INFO_BW_5) 83 bss_meta.scan_width = NL80211_BSS_CHAN_WIDTH_5; 84 else if (rx_status->bw == RATE_INFO_BW_10) 85 bss_meta.scan_width = NL80211_BSS_CHAN_WIDTH_10; 86 87 bss_meta.chan = channel; 88 89 rcu_read_lock(); 90 scan_sdata = rcu_dereference(local->scan_sdata); 91 if (scan_sdata && scan_sdata->vif.type == NL80211_IFTYPE_STATION && 92 scan_sdata->vif.bss_conf.assoc && 93 ieee80211_have_rx_timestamp(rx_status)) { 94 bss_meta.parent_tsf = 95 ieee80211_calculate_rx_timestamp(local, rx_status, 96 len + FCS_LEN, 24); 97 ether_addr_copy(bss_meta.parent_bssid, 98 scan_sdata->vif.bss_conf.bssid); 99 } 100 rcu_read_unlock(); 101 102 cbss = cfg80211_inform_bss_frame_data(local->hw.wiphy, &bss_meta, 103 mgmt, len, GFP_ATOMIC); 104 if (!cbss) 105 return NULL; 106 /* In case the signal is invalid update the status */ 107 signal_valid = abs(channel->center_freq - cbss->channel->center_freq) 108 <= local->hw.wiphy->max_adj_channel_rssi_comp; 109 if (!signal_valid) 110 rx_status->flag |= RX_FLAG_NO_SIGNAL_VAL; 111 112 bss = (void *)cbss->priv; 113 114 if (beacon) 115 bss->device_ts_beacon = rx_status->device_timestamp; 116 else 117 bss->device_ts_presp = rx_status->device_timestamp; 118 119 if (elems->parse_error) { 120 if (beacon) 121 bss->corrupt_data |= IEEE80211_BSS_CORRUPT_BEACON; 122 else 123 bss->corrupt_data |= IEEE80211_BSS_CORRUPT_PROBE_RESP; 124 } else { 125 if (beacon) 126 bss->corrupt_data &= ~IEEE80211_BSS_CORRUPT_BEACON; 127 else 128 bss->corrupt_data &= ~IEEE80211_BSS_CORRUPT_PROBE_RESP; 129 } 130 131 /* save the ERP value so that it is available at association time */ 132 if (elems->erp_info && (!elems->parse_error || 133 !(bss->valid_data & IEEE80211_BSS_VALID_ERP))) { 134 bss->erp_value = elems->erp_info[0]; 135 bss->has_erp_value = true; 136 if (!elems->parse_error) 137 bss->valid_data |= IEEE80211_BSS_VALID_ERP; 138 } 139 140 /* replace old supported rates if we get new values */ 141 if (!elems->parse_error || 142 !(bss->valid_data & IEEE80211_BSS_VALID_RATES)) { 143 srlen = 0; 144 if (elems->supp_rates) { 145 clen = IEEE80211_MAX_SUPP_RATES; 146 if (clen > elems->supp_rates_len) 147 clen = elems->supp_rates_len; 148 memcpy(bss->supp_rates, elems->supp_rates, clen); 149 srlen += clen; 150 } 151 if (elems->ext_supp_rates) { 152 clen = IEEE80211_MAX_SUPP_RATES - srlen; 153 if (clen > elems->ext_supp_rates_len) 154 clen = elems->ext_supp_rates_len; 155 memcpy(bss->supp_rates + srlen, elems->ext_supp_rates, 156 clen); 157 srlen += clen; 158 } 159 if (srlen) { 160 bss->supp_rates_len = srlen; 161 if (!elems->parse_error) 162 bss->valid_data |= IEEE80211_BSS_VALID_RATES; 163 } 164 } 165 166 if (!elems->parse_error || 167 !(bss->valid_data & IEEE80211_BSS_VALID_WMM)) { 168 bss->wmm_used = elems->wmm_param || elems->wmm_info; 169 bss->uapsd_supported = is_uapsd_supported(elems); 170 if (!elems->parse_error) 171 bss->valid_data |= IEEE80211_BSS_VALID_WMM; 172 } 173 174 if (beacon) { 175 struct ieee80211_supported_band *sband = 176 local->hw.wiphy->bands[rx_status->band]; 177 if (!(rx_status->encoding == RX_ENC_HT) && 178 !(rx_status->encoding == RX_ENC_VHT)) 179 bss->beacon_rate = 180 &sband->bitrates[rx_status->rate_idx]; 181 } 182 183 return bss; 184 } 185 186 static bool ieee80211_scan_accept_presp(struct ieee80211_sub_if_data *sdata, 187 u32 scan_flags, const u8 *da) 188 { 189 if (!sdata) 190 return false; 191 /* accept broadcast for OCE */ 192 if (scan_flags & NL80211_SCAN_FLAG_ACCEPT_BCAST_PROBE_RESP && 193 is_broadcast_ether_addr(da)) 194 return true; 195 if (scan_flags & NL80211_SCAN_FLAG_RANDOM_ADDR) 196 return true; 197 return ether_addr_equal(da, sdata->vif.addr); 198 } 199 200 void ieee80211_scan_rx(struct ieee80211_local *local, struct sk_buff *skb) 201 { 202 struct ieee80211_rx_status *rx_status = IEEE80211_SKB_RXCB(skb); 203 struct ieee80211_sub_if_data *sdata1, *sdata2; 204 struct ieee80211_mgmt *mgmt = (void *)skb->data; 205 struct ieee80211_bss *bss; 206 u8 *elements; 207 struct ieee80211_channel *channel; 208 size_t baselen; 209 struct ieee802_11_elems elems; 210 211 if (skb->len < 24 || 212 (!ieee80211_is_probe_resp(mgmt->frame_control) && 213 !ieee80211_is_beacon(mgmt->frame_control))) 214 return; 215 216 sdata1 = rcu_dereference(local->scan_sdata); 217 sdata2 = rcu_dereference(local->sched_scan_sdata); 218 219 if (likely(!sdata1 && !sdata2)) 220 return; 221 222 if (ieee80211_is_probe_resp(mgmt->frame_control)) { 223 struct cfg80211_scan_request *scan_req; 224 struct cfg80211_sched_scan_request *sched_scan_req; 225 u32 scan_req_flags = 0, sched_scan_req_flags = 0; 226 227 scan_req = rcu_dereference(local->scan_req); 228 sched_scan_req = rcu_dereference(local->sched_scan_req); 229 230 if (scan_req) 231 scan_req_flags = scan_req->flags; 232 233 if (sched_scan_req) 234 sched_scan_req_flags = sched_scan_req->flags; 235 236 /* ignore ProbeResp to foreign address or non-bcast (OCE) 237 * unless scanning with randomised address 238 */ 239 if (!ieee80211_scan_accept_presp(sdata1, scan_req_flags, 240 mgmt->da) && 241 !ieee80211_scan_accept_presp(sdata2, sched_scan_req_flags, 242 mgmt->da)) 243 return; 244 245 elements = mgmt->u.probe_resp.variable; 246 baselen = offsetof(struct ieee80211_mgmt, u.probe_resp.variable); 247 } else { 248 baselen = offsetof(struct ieee80211_mgmt, u.beacon.variable); 249 elements = mgmt->u.beacon.variable; 250 } 251 252 if (baselen > skb->len) 253 return; 254 255 ieee802_11_parse_elems(elements, skb->len - baselen, false, &elems); 256 257 channel = ieee80211_get_channel(local->hw.wiphy, rx_status->freq); 258 259 if (!channel || channel->flags & IEEE80211_CHAN_DISABLED) 260 return; 261 262 bss = ieee80211_bss_info_update(local, rx_status, 263 mgmt, skb->len, &elems, 264 channel); 265 if (bss) 266 ieee80211_rx_bss_put(local, bss); 267 } 268 269 static void 270 ieee80211_prepare_scan_chandef(struct cfg80211_chan_def *chandef, 271 enum nl80211_bss_scan_width scan_width) 272 { 273 memset(chandef, 0, sizeof(*chandef)); 274 switch (scan_width) { 275 case NL80211_BSS_CHAN_WIDTH_5: 276 chandef->width = NL80211_CHAN_WIDTH_5; 277 break; 278 case NL80211_BSS_CHAN_WIDTH_10: 279 chandef->width = NL80211_CHAN_WIDTH_10; 280 break; 281 default: 282 chandef->width = NL80211_CHAN_WIDTH_20_NOHT; 283 break; 284 } 285 } 286 287 /* return false if no more work */ 288 static bool ieee80211_prep_hw_scan(struct ieee80211_local *local) 289 { 290 struct cfg80211_scan_request *req; 291 struct cfg80211_chan_def chandef; 292 u8 bands_used = 0; 293 int i, ielen, n_chans; 294 295 req = rcu_dereference_protected(local->scan_req, 296 lockdep_is_held(&local->mtx)); 297 298 if (test_bit(SCAN_HW_CANCELLED, &local->scanning)) 299 return false; 300 301 if (ieee80211_hw_check(&local->hw, SINGLE_SCAN_ON_ALL_BANDS)) { 302 for (i = 0; i < req->n_channels; i++) { 303 local->hw_scan_req->req.channels[i] = req->channels[i]; 304 bands_used |= BIT(req->channels[i]->band); 305 } 306 307 n_chans = req->n_channels; 308 } else { 309 do { 310 if (local->hw_scan_band == NUM_NL80211_BANDS) 311 return false; 312 313 n_chans = 0; 314 315 for (i = 0; i < req->n_channels; i++) { 316 if (req->channels[i]->band != 317 local->hw_scan_band) 318 continue; 319 local->hw_scan_req->req.channels[n_chans] = 320 req->channels[i]; 321 n_chans++; 322 bands_used |= BIT(req->channels[i]->band); 323 } 324 325 local->hw_scan_band++; 326 } while (!n_chans); 327 } 328 329 local->hw_scan_req->req.n_channels = n_chans; 330 ieee80211_prepare_scan_chandef(&chandef, req->scan_width); 331 332 ielen = ieee80211_build_preq_ies(local, 333 (u8 *)local->hw_scan_req->req.ie, 334 local->hw_scan_ies_bufsize, 335 &local->hw_scan_req->ies, 336 req->ie, req->ie_len, 337 bands_used, req->rates, &chandef); 338 local->hw_scan_req->req.ie_len = ielen; 339 local->hw_scan_req->req.no_cck = req->no_cck; 340 ether_addr_copy(local->hw_scan_req->req.mac_addr, req->mac_addr); 341 ether_addr_copy(local->hw_scan_req->req.mac_addr_mask, 342 req->mac_addr_mask); 343 ether_addr_copy(local->hw_scan_req->req.bssid, req->bssid); 344 345 return true; 346 } 347 348 static void __ieee80211_scan_completed(struct ieee80211_hw *hw, bool aborted) 349 { 350 struct ieee80211_local *local = hw_to_local(hw); 351 bool hw_scan = local->ops->hw_scan; 352 bool was_scanning = local->scanning; 353 struct cfg80211_scan_request *scan_req; 354 struct ieee80211_sub_if_data *scan_sdata; 355 struct ieee80211_sub_if_data *sdata; 356 357 lockdep_assert_held(&local->mtx); 358 359 /* 360 * It's ok to abort a not-yet-running scan (that 361 * we have one at all will be verified by checking 362 * local->scan_req next), but not to complete it 363 * successfully. 364 */ 365 if (WARN_ON(!local->scanning && !aborted)) 366 aborted = true; 367 368 if (WARN_ON(!local->scan_req)) 369 return; 370 371 if (hw_scan && !aborted && 372 !ieee80211_hw_check(&local->hw, SINGLE_SCAN_ON_ALL_BANDS) && 373 ieee80211_prep_hw_scan(local)) { 374 int rc; 375 376 rc = drv_hw_scan(local, 377 rcu_dereference_protected(local->scan_sdata, 378 lockdep_is_held(&local->mtx)), 379 local->hw_scan_req); 380 381 if (rc == 0) 382 return; 383 384 /* HW scan failed and is going to be reported as aborted, 385 * so clear old scan info. 386 */ 387 memset(&local->scan_info, 0, sizeof(local->scan_info)); 388 aborted = true; 389 } 390 391 kfree(local->hw_scan_req); 392 local->hw_scan_req = NULL; 393 394 scan_req = rcu_dereference_protected(local->scan_req, 395 lockdep_is_held(&local->mtx)); 396 397 if (scan_req != local->int_scan_req) { 398 local->scan_info.aborted = aborted; 399 cfg80211_scan_done(scan_req, &local->scan_info); 400 } 401 RCU_INIT_POINTER(local->scan_req, NULL); 402 403 scan_sdata = rcu_dereference_protected(local->scan_sdata, 404 lockdep_is_held(&local->mtx)); 405 RCU_INIT_POINTER(local->scan_sdata, NULL); 406 407 local->scanning = 0; 408 local->scan_chandef.chan = NULL; 409 410 /* Set power back to normal operating levels. */ 411 ieee80211_hw_config(local, 0); 412 413 if (!hw_scan) { 414 ieee80211_configure_filter(local); 415 drv_sw_scan_complete(local, scan_sdata); 416 ieee80211_offchannel_return(local); 417 } 418 419 ieee80211_recalc_idle(local); 420 421 ieee80211_mlme_notify_scan_completed(local); 422 ieee80211_ibss_notify_scan_completed(local); 423 424 /* Requeue all the work that might have been ignored while 425 * the scan was in progress; if there was none this will 426 * just be a no-op for the particular interface. 427 */ 428 list_for_each_entry_rcu(sdata, &local->interfaces, list) { 429 if (ieee80211_sdata_running(sdata)) 430 ieee80211_queue_work(&sdata->local->hw, &sdata->work); 431 } 432 433 if (was_scanning) 434 ieee80211_start_next_roc(local); 435 } 436 437 void ieee80211_scan_completed(struct ieee80211_hw *hw, 438 struct cfg80211_scan_info *info) 439 { 440 struct ieee80211_local *local = hw_to_local(hw); 441 442 trace_api_scan_completed(local, info->aborted); 443 444 set_bit(SCAN_COMPLETED, &local->scanning); 445 if (info->aborted) 446 set_bit(SCAN_ABORTED, &local->scanning); 447 448 memcpy(&local->scan_info, info, sizeof(*info)); 449 450 ieee80211_queue_delayed_work(&local->hw, &local->scan_work, 0); 451 } 452 EXPORT_SYMBOL(ieee80211_scan_completed); 453 454 static int ieee80211_start_sw_scan(struct ieee80211_local *local, 455 struct ieee80211_sub_if_data *sdata) 456 { 457 /* Software scan is not supported in multi-channel cases */ 458 if (local->use_chanctx) 459 return -EOPNOTSUPP; 460 461 /* 462 * Hardware/driver doesn't support hw_scan, so use software 463 * scanning instead. First send a nullfunc frame with power save 464 * bit on so that AP will buffer the frames for us while we are not 465 * listening, then send probe requests to each channel and wait for 466 * the responses. After all channels are scanned, tune back to the 467 * original channel and send a nullfunc frame with power save bit 468 * off to trigger the AP to send us all the buffered frames. 469 * 470 * Note that while local->sw_scanning is true everything else but 471 * nullfunc frames and probe requests will be dropped in 472 * ieee80211_tx_h_check_assoc(). 473 */ 474 drv_sw_scan_start(local, sdata, local->scan_addr); 475 476 local->leave_oper_channel_time = jiffies; 477 local->next_scan_state = SCAN_DECISION; 478 local->scan_channel_idx = 0; 479 480 ieee80211_offchannel_stop_vifs(local); 481 482 /* ensure nullfunc is transmitted before leaving operating channel */ 483 ieee80211_flush_queues(local, NULL, false); 484 485 ieee80211_configure_filter(local); 486 487 /* We need to set power level at maximum rate for scanning. */ 488 ieee80211_hw_config(local, 0); 489 490 ieee80211_queue_delayed_work(&local->hw, 491 &local->scan_work, 0); 492 493 return 0; 494 } 495 496 static bool ieee80211_can_scan(struct ieee80211_local *local, 497 struct ieee80211_sub_if_data *sdata) 498 { 499 if (ieee80211_is_radar_required(local)) 500 return false; 501 502 if (!list_empty(&local->roc_list)) 503 return false; 504 505 if (sdata->vif.type == NL80211_IFTYPE_STATION && 506 sdata->u.mgd.flags & IEEE80211_STA_CONNECTION_POLL) 507 return false; 508 509 return true; 510 } 511 512 void ieee80211_run_deferred_scan(struct ieee80211_local *local) 513 { 514 lockdep_assert_held(&local->mtx); 515 516 if (!local->scan_req || local->scanning) 517 return; 518 519 if (!ieee80211_can_scan(local, 520 rcu_dereference_protected( 521 local->scan_sdata, 522 lockdep_is_held(&local->mtx)))) 523 return; 524 525 ieee80211_queue_delayed_work(&local->hw, &local->scan_work, 526 round_jiffies_relative(0)); 527 } 528 529 static void ieee80211_scan_state_send_probe(struct ieee80211_local *local, 530 unsigned long *next_delay) 531 { 532 int i; 533 struct ieee80211_sub_if_data *sdata; 534 struct cfg80211_scan_request *scan_req; 535 enum nl80211_band band = local->hw.conf.chandef.chan->band; 536 u32 tx_flags; 537 538 scan_req = rcu_dereference_protected(local->scan_req, 539 lockdep_is_held(&local->mtx)); 540 541 tx_flags = IEEE80211_TX_INTFL_OFFCHAN_TX_OK; 542 if (scan_req->no_cck) 543 tx_flags |= IEEE80211_TX_CTL_NO_CCK_RATE; 544 545 sdata = rcu_dereference_protected(local->scan_sdata, 546 lockdep_is_held(&local->mtx)); 547 548 for (i = 0; i < scan_req->n_ssids; i++) 549 ieee80211_send_probe_req( 550 sdata, local->scan_addr, scan_req->bssid, 551 scan_req->ssids[i].ssid, scan_req->ssids[i].ssid_len, 552 scan_req->ie, scan_req->ie_len, 553 scan_req->rates[band], false, 554 tx_flags, local->hw.conf.chandef.chan, true); 555 556 /* 557 * After sending probe requests, wait for probe responses 558 * on the channel. 559 */ 560 *next_delay = IEEE80211_CHANNEL_TIME; 561 local->next_scan_state = SCAN_DECISION; 562 } 563 564 static int __ieee80211_start_scan(struct ieee80211_sub_if_data *sdata, 565 struct cfg80211_scan_request *req) 566 { 567 struct ieee80211_local *local = sdata->local; 568 int rc; 569 570 lockdep_assert_held(&local->mtx); 571 572 if (local->scan_req || ieee80211_is_radar_required(local)) 573 return -EBUSY; 574 575 if (!ieee80211_can_scan(local, sdata)) { 576 /* wait for the work to finish/time out */ 577 rcu_assign_pointer(local->scan_req, req); 578 rcu_assign_pointer(local->scan_sdata, sdata); 579 return 0; 580 } 581 582 if (local->ops->hw_scan) { 583 u8 *ies; 584 585 local->hw_scan_ies_bufsize = local->scan_ies_len + req->ie_len; 586 587 if (ieee80211_hw_check(&local->hw, SINGLE_SCAN_ON_ALL_BANDS)) { 588 int i, n_bands = 0; 589 u8 bands_counted = 0; 590 591 for (i = 0; i < req->n_channels; i++) { 592 if (bands_counted & BIT(req->channels[i]->band)) 593 continue; 594 bands_counted |= BIT(req->channels[i]->band); 595 n_bands++; 596 } 597 598 local->hw_scan_ies_bufsize *= n_bands; 599 } 600 601 local->hw_scan_req = kmalloc( 602 sizeof(*local->hw_scan_req) + 603 req->n_channels * sizeof(req->channels[0]) + 604 local->hw_scan_ies_bufsize, GFP_KERNEL); 605 if (!local->hw_scan_req) 606 return -ENOMEM; 607 608 local->hw_scan_req->req.ssids = req->ssids; 609 local->hw_scan_req->req.n_ssids = req->n_ssids; 610 ies = (u8 *)local->hw_scan_req + 611 sizeof(*local->hw_scan_req) + 612 req->n_channels * sizeof(req->channels[0]); 613 local->hw_scan_req->req.ie = ies; 614 local->hw_scan_req->req.flags = req->flags; 615 eth_broadcast_addr(local->hw_scan_req->req.bssid); 616 local->hw_scan_req->req.duration = req->duration; 617 local->hw_scan_req->req.duration_mandatory = 618 req->duration_mandatory; 619 620 local->hw_scan_band = 0; 621 622 /* 623 * After allocating local->hw_scan_req, we must 624 * go through until ieee80211_prep_hw_scan(), so 625 * anything that might be changed here and leave 626 * this function early must not go after this 627 * allocation. 628 */ 629 } 630 631 rcu_assign_pointer(local->scan_req, req); 632 rcu_assign_pointer(local->scan_sdata, sdata); 633 634 if (req->flags & NL80211_SCAN_FLAG_RANDOM_ADDR) 635 get_random_mask_addr(local->scan_addr, 636 req->mac_addr, 637 req->mac_addr_mask); 638 else 639 memcpy(local->scan_addr, sdata->vif.addr, ETH_ALEN); 640 641 if (local->ops->hw_scan) { 642 __set_bit(SCAN_HW_SCANNING, &local->scanning); 643 } else if ((req->n_channels == 1) && 644 (req->channels[0] == local->_oper_chandef.chan)) { 645 /* 646 * If we are scanning only on the operating channel 647 * then we do not need to stop normal activities 648 */ 649 unsigned long next_delay; 650 651 __set_bit(SCAN_ONCHANNEL_SCANNING, &local->scanning); 652 653 ieee80211_recalc_idle(local); 654 655 /* Notify driver scan is starting, keep order of operations 656 * same as normal software scan, in case that matters. */ 657 drv_sw_scan_start(local, sdata, local->scan_addr); 658 659 ieee80211_configure_filter(local); /* accept probe-responses */ 660 661 /* We need to ensure power level is at max for scanning. */ 662 ieee80211_hw_config(local, 0); 663 664 if ((req->channels[0]->flags & (IEEE80211_CHAN_NO_IR | 665 IEEE80211_CHAN_RADAR)) || 666 !req->n_ssids) { 667 next_delay = IEEE80211_PASSIVE_CHANNEL_TIME; 668 } else { 669 ieee80211_scan_state_send_probe(local, &next_delay); 670 next_delay = IEEE80211_CHANNEL_TIME; 671 } 672 673 /* Now, just wait a bit and we are all done! */ 674 ieee80211_queue_delayed_work(&local->hw, &local->scan_work, 675 next_delay); 676 return 0; 677 } else { 678 /* Do normal software scan */ 679 __set_bit(SCAN_SW_SCANNING, &local->scanning); 680 } 681 682 ieee80211_recalc_idle(local); 683 684 if (local->ops->hw_scan) { 685 WARN_ON(!ieee80211_prep_hw_scan(local)); 686 rc = drv_hw_scan(local, sdata, local->hw_scan_req); 687 } else { 688 rc = ieee80211_start_sw_scan(local, sdata); 689 } 690 691 if (rc) { 692 kfree(local->hw_scan_req); 693 local->hw_scan_req = NULL; 694 local->scanning = 0; 695 696 ieee80211_recalc_idle(local); 697 698 local->scan_req = NULL; 699 RCU_INIT_POINTER(local->scan_sdata, NULL); 700 } 701 702 return rc; 703 } 704 705 static unsigned long 706 ieee80211_scan_get_channel_time(struct ieee80211_channel *chan) 707 { 708 /* 709 * TODO: channel switching also consumes quite some time, 710 * add that delay as well to get a better estimation 711 */ 712 if (chan->flags & (IEEE80211_CHAN_NO_IR | IEEE80211_CHAN_RADAR)) 713 return IEEE80211_PASSIVE_CHANNEL_TIME; 714 return IEEE80211_PROBE_DELAY + IEEE80211_CHANNEL_TIME; 715 } 716 717 static void ieee80211_scan_state_decision(struct ieee80211_local *local, 718 unsigned long *next_delay) 719 { 720 bool associated = false; 721 bool tx_empty = true; 722 bool bad_latency; 723 struct ieee80211_sub_if_data *sdata; 724 struct ieee80211_channel *next_chan; 725 enum mac80211_scan_state next_scan_state; 726 struct cfg80211_scan_request *scan_req; 727 728 /* 729 * check if at least one STA interface is associated, 730 * check if at least one STA interface has pending tx frames 731 * and grab the lowest used beacon interval 732 */ 733 mutex_lock(&local->iflist_mtx); 734 list_for_each_entry(sdata, &local->interfaces, list) { 735 if (!ieee80211_sdata_running(sdata)) 736 continue; 737 738 if (sdata->vif.type == NL80211_IFTYPE_STATION) { 739 if (sdata->u.mgd.associated) { 740 associated = true; 741 742 if (!qdisc_all_tx_empty(sdata->dev)) { 743 tx_empty = false; 744 break; 745 } 746 } 747 } 748 } 749 mutex_unlock(&local->iflist_mtx); 750 751 scan_req = rcu_dereference_protected(local->scan_req, 752 lockdep_is_held(&local->mtx)); 753 754 next_chan = scan_req->channels[local->scan_channel_idx]; 755 756 /* 757 * we're currently scanning a different channel, let's 758 * see if we can scan another channel without interfering 759 * with the current traffic situation. 760 * 761 * Keep good latency, do not stay off-channel more than 125 ms. 762 */ 763 764 bad_latency = time_after(jiffies + 765 ieee80211_scan_get_channel_time(next_chan), 766 local->leave_oper_channel_time + HZ / 8); 767 768 if (associated && !tx_empty) { 769 if (scan_req->flags & NL80211_SCAN_FLAG_LOW_PRIORITY) 770 next_scan_state = SCAN_ABORT; 771 else 772 next_scan_state = SCAN_SUSPEND; 773 } else if (associated && bad_latency) { 774 next_scan_state = SCAN_SUSPEND; 775 } else { 776 next_scan_state = SCAN_SET_CHANNEL; 777 } 778 779 local->next_scan_state = next_scan_state; 780 781 *next_delay = 0; 782 } 783 784 static void ieee80211_scan_state_set_channel(struct ieee80211_local *local, 785 unsigned long *next_delay) 786 { 787 int skip; 788 struct ieee80211_channel *chan; 789 enum nl80211_bss_scan_width oper_scan_width; 790 struct cfg80211_scan_request *scan_req; 791 792 scan_req = rcu_dereference_protected(local->scan_req, 793 lockdep_is_held(&local->mtx)); 794 795 skip = 0; 796 chan = scan_req->channels[local->scan_channel_idx]; 797 798 local->scan_chandef.chan = chan; 799 local->scan_chandef.center_freq1 = chan->center_freq; 800 local->scan_chandef.center_freq2 = 0; 801 switch (scan_req->scan_width) { 802 case NL80211_BSS_CHAN_WIDTH_5: 803 local->scan_chandef.width = NL80211_CHAN_WIDTH_5; 804 break; 805 case NL80211_BSS_CHAN_WIDTH_10: 806 local->scan_chandef.width = NL80211_CHAN_WIDTH_10; 807 break; 808 case NL80211_BSS_CHAN_WIDTH_20: 809 /* If scanning on oper channel, use whatever channel-type 810 * is currently in use. 811 */ 812 oper_scan_width = cfg80211_chandef_to_scan_width( 813 &local->_oper_chandef); 814 if (chan == local->_oper_chandef.chan && 815 oper_scan_width == scan_req->scan_width) 816 local->scan_chandef = local->_oper_chandef; 817 else 818 local->scan_chandef.width = NL80211_CHAN_WIDTH_20_NOHT; 819 break; 820 } 821 822 if (ieee80211_hw_config(local, IEEE80211_CONF_CHANGE_CHANNEL)) 823 skip = 1; 824 825 /* advance state machine to next channel/band */ 826 local->scan_channel_idx++; 827 828 if (skip) { 829 /* if we skip this channel return to the decision state */ 830 local->next_scan_state = SCAN_DECISION; 831 return; 832 } 833 834 /* 835 * Probe delay is used to update the NAV, cf. 11.1.3.2.2 836 * (which unfortunately doesn't say _why_ step a) is done, 837 * but it waits for the probe delay or until a frame is 838 * received - and the received frame would update the NAV). 839 * For now, we do not support waiting until a frame is 840 * received. 841 * 842 * In any case, it is not necessary for a passive scan. 843 */ 844 if ((chan->flags & (IEEE80211_CHAN_NO_IR | IEEE80211_CHAN_RADAR)) || 845 !scan_req->n_ssids) { 846 *next_delay = IEEE80211_PASSIVE_CHANNEL_TIME; 847 local->next_scan_state = SCAN_DECISION; 848 return; 849 } 850 851 /* active scan, send probes */ 852 *next_delay = IEEE80211_PROBE_DELAY; 853 local->next_scan_state = SCAN_SEND_PROBE; 854 } 855 856 static void ieee80211_scan_state_suspend(struct ieee80211_local *local, 857 unsigned long *next_delay) 858 { 859 /* switch back to the operating channel */ 860 local->scan_chandef.chan = NULL; 861 ieee80211_hw_config(local, IEEE80211_CONF_CHANGE_CHANNEL); 862 863 /* disable PS */ 864 ieee80211_offchannel_return(local); 865 866 *next_delay = HZ / 5; 867 /* afterwards, resume scan & go to next channel */ 868 local->next_scan_state = SCAN_RESUME; 869 } 870 871 static void ieee80211_scan_state_resume(struct ieee80211_local *local, 872 unsigned long *next_delay) 873 { 874 ieee80211_offchannel_stop_vifs(local); 875 876 if (local->ops->flush) { 877 ieee80211_flush_queues(local, NULL, false); 878 *next_delay = 0; 879 } else 880 *next_delay = HZ / 10; 881 882 /* remember when we left the operating channel */ 883 local->leave_oper_channel_time = jiffies; 884 885 /* advance to the next channel to be scanned */ 886 local->next_scan_state = SCAN_SET_CHANNEL; 887 } 888 889 void ieee80211_scan_work(struct work_struct *work) 890 { 891 struct ieee80211_local *local = 892 container_of(work, struct ieee80211_local, scan_work.work); 893 struct ieee80211_sub_if_data *sdata; 894 struct cfg80211_scan_request *scan_req; 895 unsigned long next_delay = 0; 896 bool aborted; 897 898 mutex_lock(&local->mtx); 899 900 if (!ieee80211_can_run_worker(local)) { 901 aborted = true; 902 goto out_complete; 903 } 904 905 sdata = rcu_dereference_protected(local->scan_sdata, 906 lockdep_is_held(&local->mtx)); 907 scan_req = rcu_dereference_protected(local->scan_req, 908 lockdep_is_held(&local->mtx)); 909 910 /* When scanning on-channel, the first-callback means completed. */ 911 if (test_bit(SCAN_ONCHANNEL_SCANNING, &local->scanning)) { 912 aborted = test_and_clear_bit(SCAN_ABORTED, &local->scanning); 913 goto out_complete; 914 } 915 916 if (test_and_clear_bit(SCAN_COMPLETED, &local->scanning)) { 917 aborted = test_and_clear_bit(SCAN_ABORTED, &local->scanning); 918 goto out_complete; 919 } 920 921 if (!sdata || !scan_req) 922 goto out; 923 924 if (!local->scanning) { 925 int rc; 926 927 RCU_INIT_POINTER(local->scan_req, NULL); 928 RCU_INIT_POINTER(local->scan_sdata, NULL); 929 930 rc = __ieee80211_start_scan(sdata, scan_req); 931 if (rc) { 932 /* need to complete scan in cfg80211 */ 933 rcu_assign_pointer(local->scan_req, scan_req); 934 aborted = true; 935 goto out_complete; 936 } else 937 goto out; 938 } 939 940 /* 941 * as long as no delay is required advance immediately 942 * without scheduling a new work 943 */ 944 do { 945 if (!ieee80211_sdata_running(sdata)) { 946 aborted = true; 947 goto out_complete; 948 } 949 950 switch (local->next_scan_state) { 951 case SCAN_DECISION: 952 /* if no more bands/channels left, complete scan */ 953 if (local->scan_channel_idx >= scan_req->n_channels) { 954 aborted = false; 955 goto out_complete; 956 } 957 ieee80211_scan_state_decision(local, &next_delay); 958 break; 959 case SCAN_SET_CHANNEL: 960 ieee80211_scan_state_set_channel(local, &next_delay); 961 break; 962 case SCAN_SEND_PROBE: 963 ieee80211_scan_state_send_probe(local, &next_delay); 964 break; 965 case SCAN_SUSPEND: 966 ieee80211_scan_state_suspend(local, &next_delay); 967 break; 968 case SCAN_RESUME: 969 ieee80211_scan_state_resume(local, &next_delay); 970 break; 971 case SCAN_ABORT: 972 aborted = true; 973 goto out_complete; 974 } 975 } while (next_delay == 0); 976 977 ieee80211_queue_delayed_work(&local->hw, &local->scan_work, next_delay); 978 goto out; 979 980 out_complete: 981 __ieee80211_scan_completed(&local->hw, aborted); 982 out: 983 mutex_unlock(&local->mtx); 984 } 985 986 int ieee80211_request_scan(struct ieee80211_sub_if_data *sdata, 987 struct cfg80211_scan_request *req) 988 { 989 int res; 990 991 mutex_lock(&sdata->local->mtx); 992 res = __ieee80211_start_scan(sdata, req); 993 mutex_unlock(&sdata->local->mtx); 994 995 return res; 996 } 997 998 int ieee80211_request_ibss_scan(struct ieee80211_sub_if_data *sdata, 999 const u8 *ssid, u8 ssid_len, 1000 struct ieee80211_channel **channels, 1001 unsigned int n_channels, 1002 enum nl80211_bss_scan_width scan_width) 1003 { 1004 struct ieee80211_local *local = sdata->local; 1005 int ret = -EBUSY, i, n_ch = 0; 1006 enum nl80211_band band; 1007 1008 mutex_lock(&local->mtx); 1009 1010 /* busy scanning */ 1011 if (local->scan_req) 1012 goto unlock; 1013 1014 /* fill internal scan request */ 1015 if (!channels) { 1016 int max_n; 1017 1018 for (band = 0; band < NUM_NL80211_BANDS; band++) { 1019 if (!local->hw.wiphy->bands[band]) 1020 continue; 1021 1022 max_n = local->hw.wiphy->bands[band]->n_channels; 1023 for (i = 0; i < max_n; i++) { 1024 struct ieee80211_channel *tmp_ch = 1025 &local->hw.wiphy->bands[band]->channels[i]; 1026 1027 if (tmp_ch->flags & (IEEE80211_CHAN_NO_IR | 1028 IEEE80211_CHAN_DISABLED)) 1029 continue; 1030 1031 local->int_scan_req->channels[n_ch] = tmp_ch; 1032 n_ch++; 1033 } 1034 } 1035 1036 if (WARN_ON_ONCE(n_ch == 0)) 1037 goto unlock; 1038 1039 local->int_scan_req->n_channels = n_ch; 1040 } else { 1041 for (i = 0; i < n_channels; i++) { 1042 if (channels[i]->flags & (IEEE80211_CHAN_NO_IR | 1043 IEEE80211_CHAN_DISABLED)) 1044 continue; 1045 1046 local->int_scan_req->channels[n_ch] = channels[i]; 1047 n_ch++; 1048 } 1049 1050 if (WARN_ON_ONCE(n_ch == 0)) 1051 goto unlock; 1052 1053 local->int_scan_req->n_channels = n_ch; 1054 } 1055 1056 local->int_scan_req->ssids = &local->scan_ssid; 1057 local->int_scan_req->n_ssids = 1; 1058 local->int_scan_req->scan_width = scan_width; 1059 memcpy(local->int_scan_req->ssids[0].ssid, ssid, IEEE80211_MAX_SSID_LEN); 1060 local->int_scan_req->ssids[0].ssid_len = ssid_len; 1061 1062 ret = __ieee80211_start_scan(sdata, sdata->local->int_scan_req); 1063 unlock: 1064 mutex_unlock(&local->mtx); 1065 return ret; 1066 } 1067 1068 /* 1069 * Only call this function when a scan can't be queued -- under RTNL. 1070 */ 1071 void ieee80211_scan_cancel(struct ieee80211_local *local) 1072 { 1073 /* 1074 * We are canceling software scan, or deferred scan that was not 1075 * yet really started (see __ieee80211_start_scan ). 1076 * 1077 * Regarding hardware scan: 1078 * - we can not call __ieee80211_scan_completed() as when 1079 * SCAN_HW_SCANNING bit is set this function change 1080 * local->hw_scan_req to operate on 5G band, what race with 1081 * driver which can use local->hw_scan_req 1082 * 1083 * - we can not cancel scan_work since driver can schedule it 1084 * by ieee80211_scan_completed(..., true) to finish scan 1085 * 1086 * Hence we only call the cancel_hw_scan() callback, but the low-level 1087 * driver is still responsible for calling ieee80211_scan_completed() 1088 * after the scan was completed/aborted. 1089 */ 1090 1091 mutex_lock(&local->mtx); 1092 if (!local->scan_req) 1093 goto out; 1094 1095 /* 1096 * We have a scan running and the driver already reported completion, 1097 * but the worker hasn't run yet or is stuck on the mutex - mark it as 1098 * cancelled. 1099 */ 1100 if (test_bit(SCAN_HW_SCANNING, &local->scanning) && 1101 test_bit(SCAN_COMPLETED, &local->scanning)) { 1102 set_bit(SCAN_HW_CANCELLED, &local->scanning); 1103 goto out; 1104 } 1105 1106 if (test_bit(SCAN_HW_SCANNING, &local->scanning)) { 1107 /* 1108 * Make sure that __ieee80211_scan_completed doesn't trigger a 1109 * scan on another band. 1110 */ 1111 set_bit(SCAN_HW_CANCELLED, &local->scanning); 1112 if (local->ops->cancel_hw_scan) 1113 drv_cancel_hw_scan(local, 1114 rcu_dereference_protected(local->scan_sdata, 1115 lockdep_is_held(&local->mtx))); 1116 goto out; 1117 } 1118 1119 /* 1120 * If the work is currently running, it must be blocked on 1121 * the mutex, but we'll set scan_sdata = NULL and it'll 1122 * simply exit once it acquires the mutex. 1123 */ 1124 cancel_delayed_work(&local->scan_work); 1125 /* and clean up */ 1126 memset(&local->scan_info, 0, sizeof(local->scan_info)); 1127 __ieee80211_scan_completed(&local->hw, true); 1128 out: 1129 mutex_unlock(&local->mtx); 1130 } 1131 1132 int __ieee80211_request_sched_scan_start(struct ieee80211_sub_if_data *sdata, 1133 struct cfg80211_sched_scan_request *req) 1134 { 1135 struct ieee80211_local *local = sdata->local; 1136 struct ieee80211_scan_ies sched_scan_ies = {}; 1137 struct cfg80211_chan_def chandef; 1138 int ret, i, iebufsz, num_bands = 0; 1139 u32 rate_masks[NUM_NL80211_BANDS] = {}; 1140 u8 bands_used = 0; 1141 u8 *ie; 1142 1143 iebufsz = local->scan_ies_len + req->ie_len; 1144 1145 lockdep_assert_held(&local->mtx); 1146 1147 if (!local->ops->sched_scan_start) 1148 return -ENOTSUPP; 1149 1150 for (i = 0; i < NUM_NL80211_BANDS; i++) { 1151 if (local->hw.wiphy->bands[i]) { 1152 bands_used |= BIT(i); 1153 rate_masks[i] = (u32) -1; 1154 num_bands++; 1155 } 1156 } 1157 1158 ie = kzalloc(num_bands * iebufsz, GFP_KERNEL); 1159 if (!ie) { 1160 ret = -ENOMEM; 1161 goto out; 1162 } 1163 1164 ieee80211_prepare_scan_chandef(&chandef, req->scan_width); 1165 1166 ieee80211_build_preq_ies(local, ie, num_bands * iebufsz, 1167 &sched_scan_ies, req->ie, 1168 req->ie_len, bands_used, rate_masks, &chandef); 1169 1170 ret = drv_sched_scan_start(local, sdata, req, &sched_scan_ies); 1171 if (ret == 0) { 1172 rcu_assign_pointer(local->sched_scan_sdata, sdata); 1173 rcu_assign_pointer(local->sched_scan_req, req); 1174 } 1175 1176 kfree(ie); 1177 1178 out: 1179 if (ret) { 1180 /* Clean in case of failure after HW restart or upon resume. */ 1181 RCU_INIT_POINTER(local->sched_scan_sdata, NULL); 1182 RCU_INIT_POINTER(local->sched_scan_req, NULL); 1183 } 1184 1185 return ret; 1186 } 1187 1188 int ieee80211_request_sched_scan_start(struct ieee80211_sub_if_data *sdata, 1189 struct cfg80211_sched_scan_request *req) 1190 { 1191 struct ieee80211_local *local = sdata->local; 1192 int ret; 1193 1194 mutex_lock(&local->mtx); 1195 1196 if (rcu_access_pointer(local->sched_scan_sdata)) { 1197 mutex_unlock(&local->mtx); 1198 return -EBUSY; 1199 } 1200 1201 ret = __ieee80211_request_sched_scan_start(sdata, req); 1202 1203 mutex_unlock(&local->mtx); 1204 return ret; 1205 } 1206 1207 int ieee80211_request_sched_scan_stop(struct ieee80211_local *local) 1208 { 1209 struct ieee80211_sub_if_data *sched_scan_sdata; 1210 int ret = -ENOENT; 1211 1212 mutex_lock(&local->mtx); 1213 1214 if (!local->ops->sched_scan_stop) { 1215 ret = -ENOTSUPP; 1216 goto out; 1217 } 1218 1219 /* We don't want to restart sched scan anymore. */ 1220 RCU_INIT_POINTER(local->sched_scan_req, NULL); 1221 1222 sched_scan_sdata = rcu_dereference_protected(local->sched_scan_sdata, 1223 lockdep_is_held(&local->mtx)); 1224 if (sched_scan_sdata) { 1225 ret = drv_sched_scan_stop(local, sched_scan_sdata); 1226 if (!ret) 1227 RCU_INIT_POINTER(local->sched_scan_sdata, NULL); 1228 } 1229 out: 1230 mutex_unlock(&local->mtx); 1231 1232 return ret; 1233 } 1234 1235 void ieee80211_sched_scan_results(struct ieee80211_hw *hw) 1236 { 1237 struct ieee80211_local *local = hw_to_local(hw); 1238 1239 trace_api_sched_scan_results(local); 1240 1241 cfg80211_sched_scan_results(hw->wiphy, 0); 1242 } 1243 EXPORT_SYMBOL(ieee80211_sched_scan_results); 1244 1245 void ieee80211_sched_scan_end(struct ieee80211_local *local) 1246 { 1247 mutex_lock(&local->mtx); 1248 1249 if (!rcu_access_pointer(local->sched_scan_sdata)) { 1250 mutex_unlock(&local->mtx); 1251 return; 1252 } 1253 1254 RCU_INIT_POINTER(local->sched_scan_sdata, NULL); 1255 1256 /* If sched scan was aborted by the driver. */ 1257 RCU_INIT_POINTER(local->sched_scan_req, NULL); 1258 1259 mutex_unlock(&local->mtx); 1260 1261 cfg80211_sched_scan_stopped(local->hw.wiphy, 0); 1262 } 1263 1264 void ieee80211_sched_scan_stopped_work(struct work_struct *work) 1265 { 1266 struct ieee80211_local *local = 1267 container_of(work, struct ieee80211_local, 1268 sched_scan_stopped_work); 1269 1270 ieee80211_sched_scan_end(local); 1271 } 1272 1273 void ieee80211_sched_scan_stopped(struct ieee80211_hw *hw) 1274 { 1275 struct ieee80211_local *local = hw_to_local(hw); 1276 1277 trace_api_sched_scan_stopped(local); 1278 1279 /* 1280 * this shouldn't really happen, so for simplicity 1281 * simply ignore it, and let mac80211 reconfigure 1282 * the sched scan later on. 1283 */ 1284 if (local->in_reconfig) 1285 return; 1286 1287 schedule_work(&local->sched_scan_stopped_work); 1288 } 1289 EXPORT_SYMBOL(ieee80211_sched_scan_stopped); 1290