| 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/rtnetlink.h> |
| 17 | #include <linux/pm_qos_params.h> |
| 18 | #include <net/sch_generic.h> |
| 19 | #include <net/mac80211.h> |
| 20 | |
| 21 | #include "ieee80211_i.h" |
| 22 | #include "driver-ops.h" |
| 23 | #include "mesh.h" |
| 24 | |
| 25 | #define IEEE80211_PROBE_DELAY (HZ / 33) |
| 26 | #define IEEE80211_CHANNEL_TIME (HZ / 33) |
| 27 | #define IEEE80211_PASSIVE_CHANNEL_TIME (HZ / 8) |
| 28 | |
| 29 | struct ieee80211_bss * |
| 30 | ieee80211_rx_bss_get(struct ieee80211_local *local, u8 *bssid, int freq, |
| 31 | u8 *ssid, u8 ssid_len) |
| 32 | { |
| 33 | struct cfg80211_bss *cbss; |
| 34 | |
| 35 | cbss = cfg80211_get_bss(local->hw.wiphy, |
| 36 | ieee80211_get_channel(local->hw.wiphy, freq), |
| 37 | bssid, ssid, ssid_len, 0, 0); |
| 38 | if (!cbss) |
| 39 | return NULL; |
| 40 | return (void *)cbss->priv; |
| 41 | } |
| 42 | |
| 43 | static void ieee80211_rx_bss_free(struct cfg80211_bss *cbss) |
| 44 | { |
| 45 | struct ieee80211_bss *bss = (void *)cbss->priv; |
| 46 | |
| 47 | kfree(bss_mesh_id(bss)); |
| 48 | kfree(bss_mesh_cfg(bss)); |
| 49 | } |
| 50 | |
| 51 | void ieee80211_rx_bss_put(struct ieee80211_local *local, |
| 52 | struct ieee80211_bss *bss) |
| 53 | { |
| 54 | if (!bss) |
| 55 | return; |
| 56 | cfg80211_put_bss(container_of((void *)bss, struct cfg80211_bss, priv)); |
| 57 | } |
| 58 | |
| 59 | static bool is_uapsd_supported(struct ieee802_11_elems *elems) |
| 60 | { |
| 61 | u8 qos_info; |
| 62 | |
| 63 | if (elems->wmm_info && elems->wmm_info_len == 7 |
| 64 | && elems->wmm_info[5] == 1) |
| 65 | qos_info = elems->wmm_info[6]; |
| 66 | else if (elems->wmm_param && elems->wmm_param_len == 24 |
| 67 | && elems->wmm_param[5] == 1) |
| 68 | qos_info = elems->wmm_param[6]; |
| 69 | else |
| 70 | /* no valid wmm information or parameter element found */ |
| 71 | return false; |
| 72 | |
| 73 | return qos_info & IEEE80211_WMM_IE_AP_QOSINFO_UAPSD; |
| 74 | } |
| 75 | |
| 76 | struct ieee80211_bss * |
| 77 | ieee80211_bss_info_update(struct ieee80211_local *local, |
| 78 | struct ieee80211_rx_status *rx_status, |
| 79 | struct ieee80211_mgmt *mgmt, |
| 80 | size_t len, |
| 81 | struct ieee802_11_elems *elems, |
| 82 | struct ieee80211_channel *channel, |
| 83 | bool beacon) |
| 84 | { |
| 85 | struct cfg80211_bss *cbss; |
| 86 | struct ieee80211_bss *bss; |
| 87 | int clen, srlen; |
| 88 | s32 signal = 0; |
| 89 | |
| 90 | if (local->hw.flags & IEEE80211_HW_SIGNAL_DBM) |
| 91 | signal = rx_status->signal * 100; |
| 92 | else if (local->hw.flags & IEEE80211_HW_SIGNAL_UNSPEC) |
| 93 | signal = (rx_status->signal * 100) / local->hw.max_signal; |
| 94 | |
| 95 | cbss = cfg80211_inform_bss_frame(local->hw.wiphy, channel, |
| 96 | mgmt, len, signal, GFP_ATOMIC); |
| 97 | |
| 98 | if (!cbss) |
| 99 | return NULL; |
| 100 | |
| 101 | cbss->free_priv = ieee80211_rx_bss_free; |
| 102 | bss = (void *)cbss->priv; |
| 103 | |
| 104 | /* save the ERP value so that it is available at association time */ |
| 105 | if (elems->erp_info && elems->erp_info_len >= 1) { |
| 106 | bss->erp_value = elems->erp_info[0]; |
| 107 | bss->has_erp_value = 1; |
| 108 | } |
| 109 | |
| 110 | if (elems->tim) { |
| 111 | struct ieee80211_tim_ie *tim_ie = |
| 112 | (struct ieee80211_tim_ie *)elems->tim; |
| 113 | bss->dtim_period = tim_ie->dtim_period; |
| 114 | } |
| 115 | |
| 116 | /* replace old supported rates if we get new values */ |
| 117 | srlen = 0; |
| 118 | if (elems->supp_rates) { |
| 119 | clen = IEEE80211_MAX_SUPP_RATES; |
| 120 | if (clen > elems->supp_rates_len) |
| 121 | clen = elems->supp_rates_len; |
| 122 | memcpy(bss->supp_rates, elems->supp_rates, clen); |
| 123 | srlen += clen; |
| 124 | } |
| 125 | if (elems->ext_supp_rates) { |
| 126 | clen = IEEE80211_MAX_SUPP_RATES - srlen; |
| 127 | if (clen > elems->ext_supp_rates_len) |
| 128 | clen = elems->ext_supp_rates_len; |
| 129 | memcpy(bss->supp_rates + srlen, elems->ext_supp_rates, clen); |
| 130 | srlen += clen; |
| 131 | } |
| 132 | if (srlen) |
| 133 | bss->supp_rates_len = srlen; |
| 134 | |
| 135 | bss->wmm_used = elems->wmm_param || elems->wmm_info; |
| 136 | bss->uapsd_supported = is_uapsd_supported(elems); |
| 137 | |
| 138 | if (!beacon) |
| 139 | bss->last_probe_resp = jiffies; |
| 140 | |
| 141 | return bss; |
| 142 | } |
| 143 | |
| 144 | ieee80211_rx_result |
| 145 | ieee80211_scan_rx(struct ieee80211_sub_if_data *sdata, struct sk_buff *skb) |
| 146 | { |
| 147 | struct ieee80211_rx_status *rx_status = IEEE80211_SKB_RXCB(skb); |
| 148 | struct ieee80211_mgmt *mgmt; |
| 149 | struct ieee80211_bss *bss; |
| 150 | u8 *elements; |
| 151 | struct ieee80211_channel *channel; |
| 152 | size_t baselen; |
| 153 | int freq; |
| 154 | __le16 fc; |
| 155 | bool presp, beacon = false; |
| 156 | struct ieee802_11_elems elems; |
| 157 | |
| 158 | if (skb->len < 2) |
| 159 | return RX_DROP_UNUSABLE; |
| 160 | |
| 161 | mgmt = (struct ieee80211_mgmt *) skb->data; |
| 162 | fc = mgmt->frame_control; |
| 163 | |
| 164 | if (ieee80211_is_ctl(fc)) |
| 165 | return RX_CONTINUE; |
| 166 | |
| 167 | if (skb->len < 24) |
| 168 | return RX_DROP_MONITOR; |
| 169 | |
| 170 | presp = ieee80211_is_probe_resp(fc); |
| 171 | if (presp) { |
| 172 | /* ignore ProbeResp to foreign address */ |
| 173 | if (memcmp(mgmt->da, sdata->vif.addr, ETH_ALEN)) |
| 174 | return RX_DROP_MONITOR; |
| 175 | |
| 176 | presp = true; |
| 177 | elements = mgmt->u.probe_resp.variable; |
| 178 | baselen = offsetof(struct ieee80211_mgmt, u.probe_resp.variable); |
| 179 | } else { |
| 180 | beacon = ieee80211_is_beacon(fc); |
| 181 | baselen = offsetof(struct ieee80211_mgmt, u.beacon.variable); |
| 182 | elements = mgmt->u.beacon.variable; |
| 183 | } |
| 184 | |
| 185 | if (!presp && !beacon) |
| 186 | return RX_CONTINUE; |
| 187 | |
| 188 | if (baselen > skb->len) |
| 189 | return RX_DROP_MONITOR; |
| 190 | |
| 191 | ieee802_11_parse_elems(elements, skb->len - baselen, &elems); |
| 192 | |
| 193 | if (elems.ds_params && elems.ds_params_len == 1) |
| 194 | freq = ieee80211_channel_to_frequency(elems.ds_params[0]); |
| 195 | else |
| 196 | freq = rx_status->freq; |
| 197 | |
| 198 | channel = ieee80211_get_channel(sdata->local->hw.wiphy, freq); |
| 199 | |
| 200 | if (!channel || channel->flags & IEEE80211_CHAN_DISABLED) |
| 201 | return RX_DROP_MONITOR; |
| 202 | |
| 203 | bss = ieee80211_bss_info_update(sdata->local, rx_status, |
| 204 | mgmt, skb->len, &elems, |
| 205 | channel, beacon); |
| 206 | if (bss) |
| 207 | ieee80211_rx_bss_put(sdata->local, bss); |
| 208 | |
| 209 | dev_kfree_skb(skb); |
| 210 | return RX_QUEUED; |
| 211 | } |
| 212 | |
| 213 | /* return false if no more work */ |
| 214 | static bool ieee80211_prep_hw_scan(struct ieee80211_local *local) |
| 215 | { |
| 216 | struct cfg80211_scan_request *req = local->scan_req; |
| 217 | enum ieee80211_band band; |
| 218 | int i, ielen, n_chans; |
| 219 | |
| 220 | do { |
| 221 | if (local->hw_scan_band == IEEE80211_NUM_BANDS) |
| 222 | return false; |
| 223 | |
| 224 | band = local->hw_scan_band; |
| 225 | n_chans = 0; |
| 226 | for (i = 0; i < req->n_channels; i++) { |
| 227 | if (req->channels[i]->band == band) { |
| 228 | local->hw_scan_req->channels[n_chans] = |
| 229 | req->channels[i]; |
| 230 | n_chans++; |
| 231 | } |
| 232 | } |
| 233 | |
| 234 | local->hw_scan_band++; |
| 235 | } while (!n_chans); |
| 236 | |
| 237 | local->hw_scan_req->n_channels = n_chans; |
| 238 | |
| 239 | ielen = ieee80211_build_preq_ies(local, (u8 *)local->hw_scan_req->ie, |
| 240 | req->ie, req->ie_len, band); |
| 241 | local->hw_scan_req->ie_len = ielen; |
| 242 | |
| 243 | return true; |
| 244 | } |
| 245 | |
| 246 | void ieee80211_scan_completed(struct ieee80211_hw *hw, bool aborted) |
| 247 | { |
| 248 | struct ieee80211_local *local = hw_to_local(hw); |
| 249 | bool was_hw_scan; |
| 250 | |
| 251 | trace_api_scan_completed(local, aborted); |
| 252 | |
| 253 | mutex_lock(&local->scan_mtx); |
| 254 | |
| 255 | /* |
| 256 | * It's ok to abort a not-yet-running scan (that |
| 257 | * we have one at all will be verified by checking |
| 258 | * local->scan_req next), but not to complete it |
| 259 | * successfully. |
| 260 | */ |
| 261 | if (WARN_ON(!local->scanning && !aborted)) |
| 262 | aborted = true; |
| 263 | |
| 264 | if (WARN_ON(!local->scan_req)) { |
| 265 | mutex_unlock(&local->scan_mtx); |
| 266 | return; |
| 267 | } |
| 268 | |
| 269 | was_hw_scan = test_bit(SCAN_HW_SCANNING, &local->scanning); |
| 270 | if (was_hw_scan && !aborted && ieee80211_prep_hw_scan(local)) { |
| 271 | ieee80211_queue_delayed_work(&local->hw, |
| 272 | &local->scan_work, 0); |
| 273 | mutex_unlock(&local->scan_mtx); |
| 274 | return; |
| 275 | } |
| 276 | |
| 277 | kfree(local->hw_scan_req); |
| 278 | local->hw_scan_req = NULL; |
| 279 | |
| 280 | if (local->scan_req != local->int_scan_req) |
| 281 | cfg80211_scan_done(local->scan_req, aborted); |
| 282 | local->scan_req = NULL; |
| 283 | local->scan_sdata = NULL; |
| 284 | |
| 285 | local->scanning = 0; |
| 286 | local->scan_channel = NULL; |
| 287 | |
| 288 | /* we only have to protect scan_req and hw/sw scan */ |
| 289 | mutex_unlock(&local->scan_mtx); |
| 290 | |
| 291 | ieee80211_hw_config(local, IEEE80211_CONF_CHANGE_CHANNEL); |
| 292 | if (was_hw_scan) |
| 293 | goto done; |
| 294 | |
| 295 | ieee80211_configure_filter(local); |
| 296 | |
| 297 | drv_sw_scan_complete(local); |
| 298 | |
| 299 | ieee80211_offchannel_return(local, true); |
| 300 | |
| 301 | done: |
| 302 | ieee80211_recalc_idle(local); |
| 303 | ieee80211_mlme_notify_scan_completed(local); |
| 304 | ieee80211_ibss_notify_scan_completed(local); |
| 305 | ieee80211_mesh_notify_scan_completed(local); |
| 306 | ieee80211_queue_work(&local->hw, &local->work_work); |
| 307 | } |
| 308 | EXPORT_SYMBOL(ieee80211_scan_completed); |
| 309 | |
| 310 | static int ieee80211_start_sw_scan(struct ieee80211_local *local) |
| 311 | { |
| 312 | /* |
| 313 | * Hardware/driver doesn't support hw_scan, so use software |
| 314 | * scanning instead. First send a nullfunc frame with power save |
| 315 | * bit on so that AP will buffer the frames for us while we are not |
| 316 | * listening, then send probe requests to each channel and wait for |
| 317 | * the responses. After all channels are scanned, tune back to the |
| 318 | * original channel and send a nullfunc frame with power save bit |
| 319 | * off to trigger the AP to send us all the buffered frames. |
| 320 | * |
| 321 | * Note that while local->sw_scanning is true everything else but |
| 322 | * nullfunc frames and probe requests will be dropped in |
| 323 | * ieee80211_tx_h_check_assoc(). |
| 324 | */ |
| 325 | drv_sw_scan_start(local); |
| 326 | |
| 327 | ieee80211_offchannel_stop_beaconing(local); |
| 328 | |
| 329 | local->leave_oper_channel_time = 0; |
| 330 | local->next_scan_state = SCAN_DECISION; |
| 331 | local->scan_channel_idx = 0; |
| 332 | |
| 333 | drv_flush(local, false); |
| 334 | |
| 335 | ieee80211_configure_filter(local); |
| 336 | |
| 337 | ieee80211_queue_delayed_work(&local->hw, |
| 338 | &local->scan_work, |
| 339 | IEEE80211_CHANNEL_TIME); |
| 340 | |
| 341 | return 0; |
| 342 | } |
| 343 | |
| 344 | |
| 345 | static int __ieee80211_start_scan(struct ieee80211_sub_if_data *sdata, |
| 346 | struct cfg80211_scan_request *req) |
| 347 | { |
| 348 | struct ieee80211_local *local = sdata->local; |
| 349 | int rc; |
| 350 | |
| 351 | if (local->scan_req) |
| 352 | return -EBUSY; |
| 353 | |
| 354 | if (!list_empty(&local->work_list)) { |
| 355 | /* wait for the work to finish/time out */ |
| 356 | local->scan_req = req; |
| 357 | local->scan_sdata = sdata; |
| 358 | return 0; |
| 359 | } |
| 360 | |
| 361 | if (local->ops->hw_scan) { |
| 362 | u8 *ies; |
| 363 | |
| 364 | local->hw_scan_req = kmalloc( |
| 365 | sizeof(*local->hw_scan_req) + |
| 366 | req->n_channels * sizeof(req->channels[0]) + |
| 367 | 2 + IEEE80211_MAX_SSID_LEN + local->scan_ies_len + |
| 368 | req->ie_len, GFP_KERNEL); |
| 369 | if (!local->hw_scan_req) |
| 370 | return -ENOMEM; |
| 371 | |
| 372 | local->hw_scan_req->ssids = req->ssids; |
| 373 | local->hw_scan_req->n_ssids = req->n_ssids; |
| 374 | ies = (u8 *)local->hw_scan_req + |
| 375 | sizeof(*local->hw_scan_req) + |
| 376 | req->n_channels * sizeof(req->channels[0]); |
| 377 | local->hw_scan_req->ie = ies; |
| 378 | |
| 379 | local->hw_scan_band = 0; |
| 380 | |
| 381 | /* |
| 382 | * After allocating local->hw_scan_req, we must |
| 383 | * go through until ieee80211_prep_hw_scan(), so |
| 384 | * anything that might be changed here and leave |
| 385 | * this function early must not go after this |
| 386 | * allocation. |
| 387 | */ |
| 388 | } |
| 389 | |
| 390 | local->scan_req = req; |
| 391 | local->scan_sdata = sdata; |
| 392 | |
| 393 | if (local->ops->hw_scan) |
| 394 | __set_bit(SCAN_HW_SCANNING, &local->scanning); |
| 395 | else |
| 396 | __set_bit(SCAN_SW_SCANNING, &local->scanning); |
| 397 | |
| 398 | /* |
| 399 | * Kicking off the scan need not be protected, |
| 400 | * only the scan variable stuff, since now |
| 401 | * local->scan_req is assigned and other callers |
| 402 | * will abort their scan attempts. |
| 403 | * |
| 404 | * This avoids too many locking dependencies |
| 405 | * so that the scan completed calls have more |
| 406 | * locking freedom. |
| 407 | */ |
| 408 | |
| 409 | ieee80211_recalc_idle(local); |
| 410 | mutex_unlock(&local->scan_mtx); |
| 411 | |
| 412 | if (local->ops->hw_scan) { |
| 413 | WARN_ON(!ieee80211_prep_hw_scan(local)); |
| 414 | rc = drv_hw_scan(local, sdata, local->hw_scan_req); |
| 415 | } else |
| 416 | rc = ieee80211_start_sw_scan(local); |
| 417 | |
| 418 | mutex_lock(&local->scan_mtx); |
| 419 | |
| 420 | if (rc) { |
| 421 | kfree(local->hw_scan_req); |
| 422 | local->hw_scan_req = NULL; |
| 423 | local->scanning = 0; |
| 424 | |
| 425 | ieee80211_recalc_idle(local); |
| 426 | |
| 427 | local->scan_req = NULL; |
| 428 | local->scan_sdata = NULL; |
| 429 | } |
| 430 | |
| 431 | return rc; |
| 432 | } |
| 433 | |
| 434 | static unsigned long |
| 435 | ieee80211_scan_get_channel_time(struct ieee80211_channel *chan) |
| 436 | { |
| 437 | /* |
| 438 | * TODO: channel switching also consumes quite some time, |
| 439 | * add that delay as well to get a better estimation |
| 440 | */ |
| 441 | if (chan->flags & IEEE80211_CHAN_PASSIVE_SCAN) |
| 442 | return IEEE80211_PASSIVE_CHANNEL_TIME; |
| 443 | return IEEE80211_PROBE_DELAY + IEEE80211_CHANNEL_TIME; |
| 444 | } |
| 445 | |
| 446 | static int ieee80211_scan_state_decision(struct ieee80211_local *local, |
| 447 | unsigned long *next_delay) |
| 448 | { |
| 449 | bool associated = false; |
| 450 | bool tx_empty = true; |
| 451 | bool bad_latency; |
| 452 | bool listen_int_exceeded; |
| 453 | unsigned long min_beacon_int = 0; |
| 454 | struct ieee80211_sub_if_data *sdata; |
| 455 | struct ieee80211_channel *next_chan; |
| 456 | |
| 457 | /* if no more bands/channels left, complete scan and advance to the idle state */ |
| 458 | if (local->scan_channel_idx >= local->scan_req->n_channels) { |
| 459 | ieee80211_scan_completed(&local->hw, false); |
| 460 | return 1; |
| 461 | } |
| 462 | |
| 463 | /* |
| 464 | * check if at least one STA interface is associated, |
| 465 | * check if at least one STA interface has pending tx frames |
| 466 | * and grab the lowest used beacon interval |
| 467 | */ |
| 468 | mutex_lock(&local->iflist_mtx); |
| 469 | list_for_each_entry(sdata, &local->interfaces, list) { |
| 470 | if (!ieee80211_sdata_running(sdata)) |
| 471 | continue; |
| 472 | |
| 473 | if (sdata->vif.type == NL80211_IFTYPE_STATION) { |
| 474 | if (sdata->u.mgd.associated) { |
| 475 | associated = true; |
| 476 | |
| 477 | if (sdata->vif.bss_conf.beacon_int < |
| 478 | min_beacon_int || min_beacon_int == 0) |
| 479 | min_beacon_int = |
| 480 | sdata->vif.bss_conf.beacon_int; |
| 481 | |
| 482 | if (!qdisc_all_tx_empty(sdata->dev)) { |
| 483 | tx_empty = false; |
| 484 | break; |
| 485 | } |
| 486 | } |
| 487 | } |
| 488 | } |
| 489 | mutex_unlock(&local->iflist_mtx); |
| 490 | |
| 491 | if (local->scan_channel) { |
| 492 | /* |
| 493 | * we're currently scanning a different channel, let's |
| 494 | * see if we can scan another channel without interfering |
| 495 | * with the current traffic situation. |
| 496 | * |
| 497 | * Since we don't know if the AP has pending frames for us |
| 498 | * we can only check for our tx queues and use the current |
| 499 | * pm_qos requirements for rx. Hence, if no tx traffic occurs |
| 500 | * at all we will scan as many channels in a row as the pm_qos |
| 501 | * latency allows us to. Additionally we also check for the |
| 502 | * currently negotiated listen interval to prevent losing |
| 503 | * frames unnecessarily. |
| 504 | * |
| 505 | * Otherwise switch back to the operating channel. |
| 506 | */ |
| 507 | next_chan = local->scan_req->channels[local->scan_channel_idx]; |
| 508 | |
| 509 | bad_latency = time_after(jiffies + |
| 510 | ieee80211_scan_get_channel_time(next_chan), |
| 511 | local->leave_oper_channel_time + |
| 512 | usecs_to_jiffies(pm_qos_requirement(PM_QOS_NETWORK_LATENCY))); |
| 513 | |
| 514 | listen_int_exceeded = time_after(jiffies + |
| 515 | ieee80211_scan_get_channel_time(next_chan), |
| 516 | local->leave_oper_channel_time + |
| 517 | usecs_to_jiffies(min_beacon_int * 1024) * |
| 518 | local->hw.conf.listen_interval); |
| 519 | |
| 520 | if (associated && ( !tx_empty || bad_latency || |
| 521 | listen_int_exceeded)) |
| 522 | local->next_scan_state = SCAN_ENTER_OPER_CHANNEL; |
| 523 | else |
| 524 | local->next_scan_state = SCAN_SET_CHANNEL; |
| 525 | } else { |
| 526 | /* |
| 527 | * we're on the operating channel currently, let's |
| 528 | * leave that channel now to scan another one |
| 529 | */ |
| 530 | local->next_scan_state = SCAN_LEAVE_OPER_CHANNEL; |
| 531 | } |
| 532 | |
| 533 | *next_delay = 0; |
| 534 | return 0; |
| 535 | } |
| 536 | |
| 537 | static void ieee80211_scan_state_leave_oper_channel(struct ieee80211_local *local, |
| 538 | unsigned long *next_delay) |
| 539 | { |
| 540 | ieee80211_offchannel_stop_station(local); |
| 541 | |
| 542 | __set_bit(SCAN_OFF_CHANNEL, &local->scanning); |
| 543 | |
| 544 | /* |
| 545 | * What if the nullfunc frames didn't arrive? |
| 546 | */ |
| 547 | drv_flush(local, false); |
| 548 | if (local->ops->flush) |
| 549 | *next_delay = 0; |
| 550 | else |
| 551 | *next_delay = HZ / 10; |
| 552 | |
| 553 | /* remember when we left the operating channel */ |
| 554 | local->leave_oper_channel_time = jiffies; |
| 555 | |
| 556 | /* advance to the next channel to be scanned */ |
| 557 | local->next_scan_state = SCAN_SET_CHANNEL; |
| 558 | } |
| 559 | |
| 560 | static void ieee80211_scan_state_enter_oper_channel(struct ieee80211_local *local, |
| 561 | unsigned long *next_delay) |
| 562 | { |
| 563 | /* switch back to the operating channel */ |
| 564 | local->scan_channel = NULL; |
| 565 | ieee80211_hw_config(local, IEEE80211_CONF_CHANGE_CHANNEL); |
| 566 | |
| 567 | /* |
| 568 | * Only re-enable station mode interface now; beaconing will be |
| 569 | * re-enabled once the full scan has been completed. |
| 570 | */ |
| 571 | ieee80211_offchannel_return(local, false); |
| 572 | |
| 573 | __clear_bit(SCAN_OFF_CHANNEL, &local->scanning); |
| 574 | |
| 575 | *next_delay = HZ / 5; |
| 576 | local->next_scan_state = SCAN_DECISION; |
| 577 | } |
| 578 | |
| 579 | static void ieee80211_scan_state_set_channel(struct ieee80211_local *local, |
| 580 | unsigned long *next_delay) |
| 581 | { |
| 582 | int skip; |
| 583 | struct ieee80211_channel *chan; |
| 584 | |
| 585 | skip = 0; |
| 586 | chan = local->scan_req->channels[local->scan_channel_idx]; |
| 587 | |
| 588 | local->scan_channel = chan; |
| 589 | if (ieee80211_hw_config(local, IEEE80211_CONF_CHANGE_CHANNEL)) |
| 590 | skip = 1; |
| 591 | |
| 592 | /* advance state machine to next channel/band */ |
| 593 | local->scan_channel_idx++; |
| 594 | |
| 595 | if (skip) { |
| 596 | /* if we skip this channel return to the decision state */ |
| 597 | local->next_scan_state = SCAN_DECISION; |
| 598 | return; |
| 599 | } |
| 600 | |
| 601 | /* |
| 602 | * Probe delay is used to update the NAV, cf. 11.1.3.2.2 |
| 603 | * (which unfortunately doesn't say _why_ step a) is done, |
| 604 | * but it waits for the probe delay or until a frame is |
| 605 | * received - and the received frame would update the NAV). |
| 606 | * For now, we do not support waiting until a frame is |
| 607 | * received. |
| 608 | * |
| 609 | * In any case, it is not necessary for a passive scan. |
| 610 | */ |
| 611 | if (chan->flags & IEEE80211_CHAN_PASSIVE_SCAN || |
| 612 | !local->scan_req->n_ssids) { |
| 613 | *next_delay = IEEE80211_PASSIVE_CHANNEL_TIME; |
| 614 | local->next_scan_state = SCAN_DECISION; |
| 615 | return; |
| 616 | } |
| 617 | |
| 618 | /* active scan, send probes */ |
| 619 | *next_delay = IEEE80211_PROBE_DELAY; |
| 620 | local->next_scan_state = SCAN_SEND_PROBE; |
| 621 | } |
| 622 | |
| 623 | static void ieee80211_scan_state_send_probe(struct ieee80211_local *local, |
| 624 | unsigned long *next_delay) |
| 625 | { |
| 626 | int i; |
| 627 | struct ieee80211_sub_if_data *sdata = local->scan_sdata; |
| 628 | |
| 629 | for (i = 0; i < local->scan_req->n_ssids; i++) |
| 630 | ieee80211_send_probe_req( |
| 631 | sdata, NULL, |
| 632 | local->scan_req->ssids[i].ssid, |
| 633 | local->scan_req->ssids[i].ssid_len, |
| 634 | local->scan_req->ie, local->scan_req->ie_len); |
| 635 | |
| 636 | /* |
| 637 | * After sending probe requests, wait for probe responses |
| 638 | * on the channel. |
| 639 | */ |
| 640 | *next_delay = IEEE80211_CHANNEL_TIME; |
| 641 | local->next_scan_state = SCAN_DECISION; |
| 642 | } |
| 643 | |
| 644 | void ieee80211_scan_work(struct work_struct *work) |
| 645 | { |
| 646 | struct ieee80211_local *local = |
| 647 | container_of(work, struct ieee80211_local, scan_work.work); |
| 648 | struct ieee80211_sub_if_data *sdata = local->scan_sdata; |
| 649 | unsigned long next_delay = 0; |
| 650 | |
| 651 | mutex_lock(&local->scan_mtx); |
| 652 | if (!sdata || !local->scan_req) { |
| 653 | mutex_unlock(&local->scan_mtx); |
| 654 | return; |
| 655 | } |
| 656 | |
| 657 | if (local->hw_scan_req) { |
| 658 | int rc = drv_hw_scan(local, sdata, local->hw_scan_req); |
| 659 | mutex_unlock(&local->scan_mtx); |
| 660 | if (rc) |
| 661 | ieee80211_scan_completed(&local->hw, true); |
| 662 | return; |
| 663 | } |
| 664 | |
| 665 | if (local->scan_req && !local->scanning) { |
| 666 | struct cfg80211_scan_request *req = local->scan_req; |
| 667 | int rc; |
| 668 | |
| 669 | local->scan_req = NULL; |
| 670 | local->scan_sdata = NULL; |
| 671 | |
| 672 | rc = __ieee80211_start_scan(sdata, req); |
| 673 | mutex_unlock(&local->scan_mtx); |
| 674 | |
| 675 | if (rc) |
| 676 | ieee80211_scan_completed(&local->hw, true); |
| 677 | return; |
| 678 | } |
| 679 | |
| 680 | mutex_unlock(&local->scan_mtx); |
| 681 | |
| 682 | /* |
| 683 | * Avoid re-scheduling when the sdata is going away. |
| 684 | */ |
| 685 | if (!ieee80211_sdata_running(sdata)) { |
| 686 | ieee80211_scan_completed(&local->hw, true); |
| 687 | return; |
| 688 | } |
| 689 | |
| 690 | /* |
| 691 | * as long as no delay is required advance immediately |
| 692 | * without scheduling a new work |
| 693 | */ |
| 694 | do { |
| 695 | switch (local->next_scan_state) { |
| 696 | case SCAN_DECISION: |
| 697 | if (ieee80211_scan_state_decision(local, &next_delay)) |
| 698 | return; |
| 699 | break; |
| 700 | case SCAN_SET_CHANNEL: |
| 701 | ieee80211_scan_state_set_channel(local, &next_delay); |
| 702 | break; |
| 703 | case SCAN_SEND_PROBE: |
| 704 | ieee80211_scan_state_send_probe(local, &next_delay); |
| 705 | break; |
| 706 | case SCAN_LEAVE_OPER_CHANNEL: |
| 707 | ieee80211_scan_state_leave_oper_channel(local, &next_delay); |
| 708 | break; |
| 709 | case SCAN_ENTER_OPER_CHANNEL: |
| 710 | ieee80211_scan_state_enter_oper_channel(local, &next_delay); |
| 711 | break; |
| 712 | } |
| 713 | } while (next_delay == 0); |
| 714 | |
| 715 | ieee80211_queue_delayed_work(&local->hw, &local->scan_work, next_delay); |
| 716 | } |
| 717 | |
| 718 | int ieee80211_request_scan(struct ieee80211_sub_if_data *sdata, |
| 719 | struct cfg80211_scan_request *req) |
| 720 | { |
| 721 | int res; |
| 722 | |
| 723 | mutex_lock(&sdata->local->scan_mtx); |
| 724 | res = __ieee80211_start_scan(sdata, req); |
| 725 | mutex_unlock(&sdata->local->scan_mtx); |
| 726 | |
| 727 | return res; |
| 728 | } |
| 729 | |
| 730 | int ieee80211_request_internal_scan(struct ieee80211_sub_if_data *sdata, |
| 731 | const u8 *ssid, u8 ssid_len) |
| 732 | { |
| 733 | struct ieee80211_local *local = sdata->local; |
| 734 | int ret = -EBUSY; |
| 735 | |
| 736 | mutex_lock(&local->scan_mtx); |
| 737 | |
| 738 | /* busy scanning */ |
| 739 | if (local->scan_req) |
| 740 | goto unlock; |
| 741 | |
| 742 | memcpy(local->int_scan_req->ssids[0].ssid, ssid, IEEE80211_MAX_SSID_LEN); |
| 743 | local->int_scan_req->ssids[0].ssid_len = ssid_len; |
| 744 | |
| 745 | ret = __ieee80211_start_scan(sdata, sdata->local->int_scan_req); |
| 746 | unlock: |
| 747 | mutex_unlock(&local->scan_mtx); |
| 748 | return ret; |
| 749 | } |
| 750 | |
| 751 | void ieee80211_scan_cancel(struct ieee80211_local *local) |
| 752 | { |
| 753 | bool abortscan; |
| 754 | |
| 755 | cancel_delayed_work_sync(&local->scan_work); |
| 756 | |
| 757 | /* |
| 758 | * Only call this function when a scan can't be |
| 759 | * queued -- mostly at suspend under RTNL. |
| 760 | */ |
| 761 | mutex_lock(&local->scan_mtx); |
| 762 | abortscan = test_bit(SCAN_SW_SCANNING, &local->scanning) || |
| 763 | (!local->scanning && local->scan_req); |
| 764 | mutex_unlock(&local->scan_mtx); |
| 765 | |
| 766 | if (abortscan) |
| 767 | ieee80211_scan_completed(&local->hw, true); |
| 768 | } |