scan.c 27 KB

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  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. #include <linux/if_arp.h>
  15. #include <linux/etherdevice.h>
  16. #include <linux/rtnetlink.h>
  17. #include <linux/pm_qos.h>
  18. #include <net/sch_generic.h>
  19. #include <linux/slab.h>
  20. #include <linux/export.h>
  21. #include <net/mac80211.h>
  22. #include "ieee80211_i.h"
  23. #include "driver-ops.h"
  24. #include "mesh.h"
  25. #define IEEE80211_PROBE_DELAY (HZ / 33)
  26. #define IEEE80211_CHANNEL_TIME (HZ / 33)
  27. #define IEEE80211_PASSIVE_CHANNEL_TIME (HZ / 8)
  28. static void ieee80211_rx_bss_free(struct cfg80211_bss *cbss)
  29. {
  30. struct ieee80211_bss *bss = (void *)cbss->priv;
  31. kfree(bss_mesh_id(bss));
  32. kfree(bss_mesh_cfg(bss));
  33. }
  34. void ieee80211_rx_bss_put(struct ieee80211_local *local,
  35. struct ieee80211_bss *bss)
  36. {
  37. if (!bss)
  38. return;
  39. cfg80211_put_bss(container_of((void *)bss, struct cfg80211_bss, priv));
  40. }
  41. static bool is_uapsd_supported(struct ieee802_11_elems *elems)
  42. {
  43. u8 qos_info;
  44. if (elems->wmm_info && elems->wmm_info_len == 7
  45. && elems->wmm_info[5] == 1)
  46. qos_info = elems->wmm_info[6];
  47. else if (elems->wmm_param && elems->wmm_param_len == 24
  48. && elems->wmm_param[5] == 1)
  49. qos_info = elems->wmm_param[6];
  50. else
  51. /* no valid wmm information or parameter element found */
  52. return false;
  53. return qos_info & IEEE80211_WMM_IE_AP_QOSINFO_UAPSD;
  54. }
  55. struct ieee80211_bss *
  56. ieee80211_bss_info_update(struct ieee80211_local *local,
  57. struct ieee80211_rx_status *rx_status,
  58. struct ieee80211_mgmt *mgmt,
  59. size_t len,
  60. struct ieee802_11_elems *elems,
  61. struct ieee80211_channel *channel,
  62. bool beacon)
  63. {
  64. struct cfg80211_bss *cbss;
  65. struct ieee80211_bss *bss;
  66. int clen, srlen;
  67. s32 signal = 0;
  68. if (local->hw.flags & IEEE80211_HW_SIGNAL_DBM)
  69. signal = rx_status->signal * 100;
  70. else if (local->hw.flags & IEEE80211_HW_SIGNAL_UNSPEC)
  71. signal = (rx_status->signal * 100) / local->hw.max_signal;
  72. cbss = cfg80211_inform_bss_frame(local->hw.wiphy, channel,
  73. mgmt, len, signal, GFP_ATOMIC);
  74. if (!cbss)
  75. return NULL;
  76. cbss->free_priv = ieee80211_rx_bss_free;
  77. bss = (void *)cbss->priv;
  78. bss->device_ts = rx_status->device_timestamp;
  79. if (elems->parse_error) {
  80. if (beacon)
  81. bss->corrupt_data |= IEEE80211_BSS_CORRUPT_BEACON;
  82. else
  83. bss->corrupt_data |= IEEE80211_BSS_CORRUPT_PROBE_RESP;
  84. } else {
  85. if (beacon)
  86. bss->corrupt_data &= ~IEEE80211_BSS_CORRUPT_BEACON;
  87. else
  88. bss->corrupt_data &= ~IEEE80211_BSS_CORRUPT_PROBE_RESP;
  89. }
  90. /* save the ERP value so that it is available at association time */
  91. if (elems->erp_info && elems->erp_info_len >= 1 &&
  92. (!elems->parse_error ||
  93. !(bss->valid_data & IEEE80211_BSS_VALID_ERP))) {
  94. bss->erp_value = elems->erp_info[0];
  95. bss->has_erp_value = true;
  96. if (!elems->parse_error)
  97. bss->valid_data |= IEEE80211_BSS_VALID_ERP;
  98. }
  99. if (elems->tim && (!elems->parse_error ||
  100. !(bss->valid_data & IEEE80211_BSS_VALID_DTIM))) {
  101. struct ieee80211_tim_ie *tim_ie = elems->tim;
  102. bss->dtim_period = tim_ie->dtim_period;
  103. if (!elems->parse_error)
  104. bss->valid_data |= IEEE80211_BSS_VALID_DTIM;
  105. }
  106. /* If the beacon had no TIM IE, or it was invalid, use 1 */
  107. if (beacon && !bss->dtim_period)
  108. bss->dtim_period = 1;
  109. /* replace old supported rates if we get new values */
  110. if (!elems->parse_error ||
  111. !(bss->valid_data & IEEE80211_BSS_VALID_RATES)) {
  112. srlen = 0;
  113. if (elems->supp_rates) {
  114. clen = IEEE80211_MAX_SUPP_RATES;
  115. if (clen > elems->supp_rates_len)
  116. clen = elems->supp_rates_len;
  117. memcpy(bss->supp_rates, elems->supp_rates, clen);
  118. srlen += clen;
  119. }
  120. if (elems->ext_supp_rates) {
  121. clen = IEEE80211_MAX_SUPP_RATES - srlen;
  122. if (clen > elems->ext_supp_rates_len)
  123. clen = elems->ext_supp_rates_len;
  124. memcpy(bss->supp_rates + srlen, elems->ext_supp_rates,
  125. clen);
  126. srlen += clen;
  127. }
  128. if (srlen) {
  129. bss->supp_rates_len = srlen;
  130. if (!elems->parse_error)
  131. bss->valid_data |= IEEE80211_BSS_VALID_RATES;
  132. }
  133. }
  134. if (!elems->parse_error ||
  135. !(bss->valid_data & IEEE80211_BSS_VALID_WMM)) {
  136. bss->wmm_used = elems->wmm_param || elems->wmm_info;
  137. bss->uapsd_supported = is_uapsd_supported(elems);
  138. if (!elems->parse_error)
  139. bss->valid_data |= IEEE80211_BSS_VALID_WMM;
  140. }
  141. if (!beacon)
  142. bss->last_probe_resp = jiffies;
  143. return bss;
  144. }
  145. void ieee80211_scan_rx(struct ieee80211_local *local, struct sk_buff *skb)
  146. {
  147. struct ieee80211_rx_status *rx_status = IEEE80211_SKB_RXCB(skb);
  148. struct ieee80211_sub_if_data *sdata1, *sdata2;
  149. struct ieee80211_mgmt *mgmt = (void *)skb->data;
  150. struct ieee80211_bss *bss;
  151. u8 *elements;
  152. struct ieee80211_channel *channel;
  153. size_t baselen;
  154. int freq;
  155. bool beacon;
  156. struct ieee802_11_elems elems;
  157. if (skb->len < 24 ||
  158. (!ieee80211_is_probe_resp(mgmt->frame_control) &&
  159. !ieee80211_is_beacon(mgmt->frame_control)))
  160. return;
  161. sdata1 = rcu_dereference(local->scan_sdata);
  162. sdata2 = rcu_dereference(local->sched_scan_sdata);
  163. if (likely(!sdata1 && !sdata2))
  164. return;
  165. if (ieee80211_is_probe_resp(mgmt->frame_control)) {
  166. /* ignore ProbeResp to foreign address */
  167. if ((!sdata1 || !ether_addr_equal(mgmt->da, sdata1->vif.addr)) &&
  168. (!sdata2 || !ether_addr_equal(mgmt->da, sdata2->vif.addr)))
  169. return;
  170. elements = mgmt->u.probe_resp.variable;
  171. baselen = offsetof(struct ieee80211_mgmt, u.probe_resp.variable);
  172. beacon = false;
  173. } else {
  174. baselen = offsetof(struct ieee80211_mgmt, u.beacon.variable);
  175. elements = mgmt->u.beacon.variable;
  176. beacon = true;
  177. }
  178. if (baselen > skb->len)
  179. return;
  180. ieee802_11_parse_elems(elements, skb->len - baselen, &elems);
  181. if (elems.ds_params && elems.ds_params_len == 1)
  182. freq = ieee80211_channel_to_frequency(elems.ds_params[0],
  183. rx_status->band);
  184. else
  185. freq = rx_status->freq;
  186. channel = ieee80211_get_channel(local->hw.wiphy, freq);
  187. if (!channel || channel->flags & IEEE80211_CHAN_DISABLED)
  188. return;
  189. bss = ieee80211_bss_info_update(local, rx_status,
  190. mgmt, skb->len, &elems,
  191. channel, beacon);
  192. if (bss)
  193. ieee80211_rx_bss_put(local, bss);
  194. }
  195. /* return false if no more work */
  196. static bool ieee80211_prep_hw_scan(struct ieee80211_local *local)
  197. {
  198. struct cfg80211_scan_request *req = local->scan_req;
  199. enum ieee80211_band band;
  200. int i, ielen, n_chans;
  201. do {
  202. if (local->hw_scan_band == IEEE80211_NUM_BANDS)
  203. return false;
  204. band = local->hw_scan_band;
  205. n_chans = 0;
  206. for (i = 0; i < req->n_channels; i++) {
  207. if (req->channels[i]->band == band) {
  208. local->hw_scan_req->channels[n_chans] =
  209. req->channels[i];
  210. n_chans++;
  211. }
  212. }
  213. local->hw_scan_band++;
  214. } while (!n_chans);
  215. local->hw_scan_req->n_channels = n_chans;
  216. ielen = ieee80211_build_preq_ies(local, (u8 *)local->hw_scan_req->ie,
  217. req->ie, req->ie_len, band,
  218. req->rates[band], 0);
  219. local->hw_scan_req->ie_len = ielen;
  220. local->hw_scan_req->no_cck = req->no_cck;
  221. return true;
  222. }
  223. static void __ieee80211_scan_completed(struct ieee80211_hw *hw, bool aborted,
  224. bool was_hw_scan)
  225. {
  226. struct ieee80211_local *local = hw_to_local(hw);
  227. lockdep_assert_held(&local->mtx);
  228. /*
  229. * It's ok to abort a not-yet-running scan (that
  230. * we have one at all will be verified by checking
  231. * local->scan_req next), but not to complete it
  232. * successfully.
  233. */
  234. if (WARN_ON(!local->scanning && !aborted))
  235. aborted = true;
  236. if (WARN_ON(!local->scan_req))
  237. return;
  238. if (was_hw_scan && !aborted && ieee80211_prep_hw_scan(local)) {
  239. int rc;
  240. rc = drv_hw_scan(local,
  241. rcu_dereference_protected(local->scan_sdata,
  242. lockdep_is_held(&local->mtx)),
  243. local->hw_scan_req);
  244. if (rc == 0)
  245. return;
  246. }
  247. kfree(local->hw_scan_req);
  248. local->hw_scan_req = NULL;
  249. if (local->scan_req != local->int_scan_req)
  250. cfg80211_scan_done(local->scan_req, aborted);
  251. local->scan_req = NULL;
  252. rcu_assign_pointer(local->scan_sdata, NULL);
  253. local->scanning = 0;
  254. local->scan_channel = NULL;
  255. /* Set power back to normal operating levels. */
  256. ieee80211_hw_config(local, 0);
  257. if (!was_hw_scan) {
  258. ieee80211_configure_filter(local);
  259. drv_sw_scan_complete(local);
  260. ieee80211_offchannel_return(local, true);
  261. }
  262. ieee80211_recalc_idle(local);
  263. ieee80211_mlme_notify_scan_completed(local);
  264. ieee80211_ibss_notify_scan_completed(local);
  265. ieee80211_mesh_notify_scan_completed(local);
  266. ieee80211_start_next_roc(local);
  267. }
  268. void ieee80211_scan_completed(struct ieee80211_hw *hw, bool aborted)
  269. {
  270. struct ieee80211_local *local = hw_to_local(hw);
  271. trace_api_scan_completed(local, aborted);
  272. set_bit(SCAN_COMPLETED, &local->scanning);
  273. if (aborted)
  274. set_bit(SCAN_ABORTED, &local->scanning);
  275. ieee80211_queue_delayed_work(&local->hw, &local->scan_work, 0);
  276. }
  277. EXPORT_SYMBOL(ieee80211_scan_completed);
  278. static int ieee80211_start_sw_scan(struct ieee80211_local *local)
  279. {
  280. /* Software scan is not supported in multi-channel cases */
  281. if (local->use_chanctx)
  282. return -EOPNOTSUPP;
  283. /*
  284. * Hardware/driver doesn't support hw_scan, so use software
  285. * scanning instead. First send a nullfunc frame with power save
  286. * bit on so that AP will buffer the frames for us while we are not
  287. * listening, then send probe requests to each channel and wait for
  288. * the responses. After all channels are scanned, tune back to the
  289. * original channel and send a nullfunc frame with power save bit
  290. * off to trigger the AP to send us all the buffered frames.
  291. *
  292. * Note that while local->sw_scanning is true everything else but
  293. * nullfunc frames and probe requests will be dropped in
  294. * ieee80211_tx_h_check_assoc().
  295. */
  296. drv_sw_scan_start(local);
  297. local->leave_oper_channel_time = jiffies;
  298. local->next_scan_state = SCAN_DECISION;
  299. local->scan_channel_idx = 0;
  300. ieee80211_offchannel_stop_vifs(local, true);
  301. ieee80211_configure_filter(local);
  302. /* We need to set power level at maximum rate for scanning. */
  303. ieee80211_hw_config(local, 0);
  304. ieee80211_queue_delayed_work(&local->hw,
  305. &local->scan_work, 0);
  306. return 0;
  307. }
  308. static bool ieee80211_can_scan(struct ieee80211_local *local,
  309. struct ieee80211_sub_if_data *sdata)
  310. {
  311. if (!list_empty(&local->roc_list))
  312. return false;
  313. if (sdata->vif.type == NL80211_IFTYPE_STATION &&
  314. sdata->u.mgd.flags & (IEEE80211_STA_BEACON_POLL |
  315. IEEE80211_STA_CONNECTION_POLL))
  316. return false;
  317. return true;
  318. }
  319. void ieee80211_run_deferred_scan(struct ieee80211_local *local)
  320. {
  321. lockdep_assert_held(&local->mtx);
  322. if (!local->scan_req || local->scanning)
  323. return;
  324. if (!ieee80211_can_scan(local,
  325. rcu_dereference_protected(
  326. local->scan_sdata,
  327. lockdep_is_held(&local->mtx))))
  328. return;
  329. ieee80211_queue_delayed_work(&local->hw, &local->scan_work,
  330. round_jiffies_relative(0));
  331. }
  332. static void ieee80211_scan_state_send_probe(struct ieee80211_local *local,
  333. unsigned long *next_delay)
  334. {
  335. int i;
  336. struct ieee80211_sub_if_data *sdata;
  337. enum ieee80211_band band = local->hw.conf.channel->band;
  338. sdata = rcu_dereference_protected(local->scan_sdata,
  339. lockdep_is_held(&local->mtx));
  340. for (i = 0; i < local->scan_req->n_ssids; i++)
  341. ieee80211_send_probe_req(
  342. sdata, NULL,
  343. local->scan_req->ssids[i].ssid,
  344. local->scan_req->ssids[i].ssid_len,
  345. local->scan_req->ie, local->scan_req->ie_len,
  346. local->scan_req->rates[band], false,
  347. local->scan_req->no_cck,
  348. local->hw.conf.channel, true);
  349. /*
  350. * After sending probe requests, wait for probe responses
  351. * on the channel.
  352. */
  353. *next_delay = IEEE80211_CHANNEL_TIME;
  354. local->next_scan_state = SCAN_DECISION;
  355. }
  356. static int __ieee80211_start_scan(struct ieee80211_sub_if_data *sdata,
  357. struct cfg80211_scan_request *req)
  358. {
  359. struct ieee80211_local *local = sdata->local;
  360. int rc;
  361. lockdep_assert_held(&local->mtx);
  362. if (local->scan_req)
  363. return -EBUSY;
  364. if (!ieee80211_can_scan(local, sdata)) {
  365. /* wait for the work to finish/time out */
  366. local->scan_req = req;
  367. rcu_assign_pointer(local->scan_sdata, sdata);
  368. return 0;
  369. }
  370. if (local->ops->hw_scan) {
  371. u8 *ies;
  372. local->hw_scan_req = kmalloc(
  373. sizeof(*local->hw_scan_req) +
  374. req->n_channels * sizeof(req->channels[0]) +
  375. 2 + IEEE80211_MAX_SSID_LEN + local->scan_ies_len +
  376. req->ie_len, GFP_KERNEL);
  377. if (!local->hw_scan_req)
  378. return -ENOMEM;
  379. local->hw_scan_req->ssids = req->ssids;
  380. local->hw_scan_req->n_ssids = req->n_ssids;
  381. ies = (u8 *)local->hw_scan_req +
  382. sizeof(*local->hw_scan_req) +
  383. req->n_channels * sizeof(req->channels[0]);
  384. local->hw_scan_req->ie = ies;
  385. local->hw_scan_band = 0;
  386. /*
  387. * After allocating local->hw_scan_req, we must
  388. * go through until ieee80211_prep_hw_scan(), so
  389. * anything that might be changed here and leave
  390. * this function early must not go after this
  391. * allocation.
  392. */
  393. }
  394. local->scan_req = req;
  395. rcu_assign_pointer(local->scan_sdata, sdata);
  396. if (local->ops->hw_scan) {
  397. __set_bit(SCAN_HW_SCANNING, &local->scanning);
  398. } else if ((req->n_channels == 1) &&
  399. (req->channels[0] == local->_oper_channel)) {
  400. /*
  401. * If we are scanning only on the operating channel
  402. * then we do not need to stop normal activities
  403. */
  404. unsigned long next_delay;
  405. __set_bit(SCAN_ONCHANNEL_SCANNING, &local->scanning);
  406. ieee80211_recalc_idle(local);
  407. /* Notify driver scan is starting, keep order of operations
  408. * same as normal software scan, in case that matters. */
  409. drv_sw_scan_start(local);
  410. ieee80211_configure_filter(local); /* accept probe-responses */
  411. /* We need to ensure power level is at max for scanning. */
  412. ieee80211_hw_config(local, 0);
  413. if ((req->channels[0]->flags &
  414. IEEE80211_CHAN_PASSIVE_SCAN) ||
  415. !local->scan_req->n_ssids) {
  416. next_delay = IEEE80211_PASSIVE_CHANNEL_TIME;
  417. } else {
  418. ieee80211_scan_state_send_probe(local, &next_delay);
  419. next_delay = IEEE80211_CHANNEL_TIME;
  420. }
  421. /* Now, just wait a bit and we are all done! */
  422. ieee80211_queue_delayed_work(&local->hw, &local->scan_work,
  423. next_delay);
  424. return 0;
  425. } else {
  426. /* Do normal software scan */
  427. __set_bit(SCAN_SW_SCANNING, &local->scanning);
  428. }
  429. ieee80211_recalc_idle(local);
  430. if (local->ops->hw_scan) {
  431. WARN_ON(!ieee80211_prep_hw_scan(local));
  432. rc = drv_hw_scan(local, sdata, local->hw_scan_req);
  433. } else
  434. rc = ieee80211_start_sw_scan(local);
  435. if (rc) {
  436. kfree(local->hw_scan_req);
  437. local->hw_scan_req = NULL;
  438. local->scanning = 0;
  439. ieee80211_recalc_idle(local);
  440. local->scan_req = NULL;
  441. rcu_assign_pointer(local->scan_sdata, NULL);
  442. }
  443. return rc;
  444. }
  445. static unsigned long
  446. ieee80211_scan_get_channel_time(struct ieee80211_channel *chan)
  447. {
  448. /*
  449. * TODO: channel switching also consumes quite some time,
  450. * add that delay as well to get a better estimation
  451. */
  452. if (chan->flags & IEEE80211_CHAN_PASSIVE_SCAN)
  453. return IEEE80211_PASSIVE_CHANNEL_TIME;
  454. return IEEE80211_PROBE_DELAY + IEEE80211_CHANNEL_TIME;
  455. }
  456. static void ieee80211_scan_state_decision(struct ieee80211_local *local,
  457. unsigned long *next_delay)
  458. {
  459. bool associated = false;
  460. bool tx_empty = true;
  461. bool bad_latency;
  462. bool listen_int_exceeded;
  463. unsigned long min_beacon_int = 0;
  464. struct ieee80211_sub_if_data *sdata;
  465. struct ieee80211_channel *next_chan;
  466. /*
  467. * check if at least one STA interface is associated,
  468. * check if at least one STA interface has pending tx frames
  469. * and grab the lowest used beacon interval
  470. */
  471. mutex_lock(&local->iflist_mtx);
  472. list_for_each_entry(sdata, &local->interfaces, list) {
  473. if (!ieee80211_sdata_running(sdata))
  474. continue;
  475. if (sdata->vif.type == NL80211_IFTYPE_STATION) {
  476. if (sdata->u.mgd.associated) {
  477. associated = true;
  478. if (sdata->vif.bss_conf.beacon_int <
  479. min_beacon_int || min_beacon_int == 0)
  480. min_beacon_int =
  481. sdata->vif.bss_conf.beacon_int;
  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. next_chan = local->scan_req->channels[local->scan_channel_idx];
  491. /*
  492. * we're currently scanning a different channel, let's
  493. * see if we can scan another channel without interfering
  494. * with the current traffic situation.
  495. *
  496. * Since we don't know if the AP has pending frames for us
  497. * we can only check for our tx queues and use the current
  498. * pm_qos requirements for rx. Hence, if no tx traffic occurs
  499. * at all we will scan as many channels in a row as the pm_qos
  500. * latency allows us to. Additionally we also check for the
  501. * currently negotiated listen interval to prevent losing
  502. * frames unnecessarily.
  503. *
  504. * Otherwise switch back to the operating channel.
  505. */
  506. bad_latency = time_after(jiffies +
  507. ieee80211_scan_get_channel_time(next_chan),
  508. local->leave_oper_channel_time +
  509. usecs_to_jiffies(pm_qos_request(PM_QOS_NETWORK_LATENCY)));
  510. listen_int_exceeded = time_after(jiffies +
  511. ieee80211_scan_get_channel_time(next_chan),
  512. local->leave_oper_channel_time +
  513. usecs_to_jiffies(min_beacon_int * 1024) *
  514. local->hw.conf.listen_interval);
  515. if (associated && (!tx_empty || bad_latency || listen_int_exceeded))
  516. local->next_scan_state = SCAN_SUSPEND;
  517. else
  518. local->next_scan_state = SCAN_SET_CHANNEL;
  519. *next_delay = 0;
  520. }
  521. static void ieee80211_scan_state_set_channel(struct ieee80211_local *local,
  522. unsigned long *next_delay)
  523. {
  524. int skip;
  525. struct ieee80211_channel *chan;
  526. skip = 0;
  527. chan = local->scan_req->channels[local->scan_channel_idx];
  528. local->scan_channel = chan;
  529. if (ieee80211_hw_config(local, IEEE80211_CONF_CHANGE_CHANNEL))
  530. skip = 1;
  531. /* advance state machine to next channel/band */
  532. local->scan_channel_idx++;
  533. if (skip) {
  534. /* if we skip this channel return to the decision state */
  535. local->next_scan_state = SCAN_DECISION;
  536. return;
  537. }
  538. /*
  539. * Probe delay is used to update the NAV, cf. 11.1.3.2.2
  540. * (which unfortunately doesn't say _why_ step a) is done,
  541. * but it waits for the probe delay or until a frame is
  542. * received - and the received frame would update the NAV).
  543. * For now, we do not support waiting until a frame is
  544. * received.
  545. *
  546. * In any case, it is not necessary for a passive scan.
  547. */
  548. if (chan->flags & IEEE80211_CHAN_PASSIVE_SCAN ||
  549. !local->scan_req->n_ssids) {
  550. *next_delay = IEEE80211_PASSIVE_CHANNEL_TIME;
  551. local->next_scan_state = SCAN_DECISION;
  552. return;
  553. }
  554. /* active scan, send probes */
  555. *next_delay = IEEE80211_PROBE_DELAY;
  556. local->next_scan_state = SCAN_SEND_PROBE;
  557. }
  558. static void ieee80211_scan_state_suspend(struct ieee80211_local *local,
  559. unsigned long *next_delay)
  560. {
  561. /* switch back to the operating channel */
  562. local->scan_channel = NULL;
  563. ieee80211_hw_config(local, IEEE80211_CONF_CHANGE_CHANNEL);
  564. /*
  565. * Re-enable vifs and beaconing. Leave PS
  566. * in off-channel state..will put that back
  567. * on-channel at the end of scanning.
  568. */
  569. ieee80211_offchannel_return(local, false);
  570. *next_delay = HZ / 5;
  571. /* afterwards, resume scan & go to next channel */
  572. local->next_scan_state = SCAN_RESUME;
  573. }
  574. static void ieee80211_scan_state_resume(struct ieee80211_local *local,
  575. unsigned long *next_delay)
  576. {
  577. /* PS already is in off-channel mode */
  578. ieee80211_offchannel_stop_vifs(local, false);
  579. if (local->ops->flush) {
  580. drv_flush(local, false);
  581. *next_delay = 0;
  582. } else
  583. *next_delay = HZ / 10;
  584. /* remember when we left the operating channel */
  585. local->leave_oper_channel_time = jiffies;
  586. /* advance to the next channel to be scanned */
  587. local->next_scan_state = SCAN_SET_CHANNEL;
  588. }
  589. void ieee80211_scan_work(struct work_struct *work)
  590. {
  591. struct ieee80211_local *local =
  592. container_of(work, struct ieee80211_local, scan_work.work);
  593. struct ieee80211_sub_if_data *sdata;
  594. unsigned long next_delay = 0;
  595. bool aborted, hw_scan;
  596. mutex_lock(&local->mtx);
  597. sdata = rcu_dereference_protected(local->scan_sdata,
  598. lockdep_is_held(&local->mtx));
  599. /* When scanning on-channel, the first-callback means completed. */
  600. if (test_bit(SCAN_ONCHANNEL_SCANNING, &local->scanning)) {
  601. aborted = test_and_clear_bit(SCAN_ABORTED, &local->scanning);
  602. goto out_complete;
  603. }
  604. if (test_and_clear_bit(SCAN_COMPLETED, &local->scanning)) {
  605. aborted = test_and_clear_bit(SCAN_ABORTED, &local->scanning);
  606. goto out_complete;
  607. }
  608. if (!sdata || !local->scan_req)
  609. goto out;
  610. if (local->scan_req && !local->scanning) {
  611. struct cfg80211_scan_request *req = local->scan_req;
  612. int rc;
  613. local->scan_req = NULL;
  614. rcu_assign_pointer(local->scan_sdata, NULL);
  615. rc = __ieee80211_start_scan(sdata, req);
  616. if (rc) {
  617. /* need to complete scan in cfg80211 */
  618. local->scan_req = req;
  619. aborted = true;
  620. goto out_complete;
  621. } else
  622. goto out;
  623. }
  624. /*
  625. * Avoid re-scheduling when the sdata is going away.
  626. */
  627. if (!ieee80211_sdata_running(sdata)) {
  628. aborted = true;
  629. goto out_complete;
  630. }
  631. /*
  632. * as long as no delay is required advance immediately
  633. * without scheduling a new work
  634. */
  635. do {
  636. if (!ieee80211_sdata_running(sdata)) {
  637. aborted = true;
  638. goto out_complete;
  639. }
  640. switch (local->next_scan_state) {
  641. case SCAN_DECISION:
  642. /* if no more bands/channels left, complete scan */
  643. if (local->scan_channel_idx >= local->scan_req->n_channels) {
  644. aborted = false;
  645. goto out_complete;
  646. }
  647. ieee80211_scan_state_decision(local, &next_delay);
  648. break;
  649. case SCAN_SET_CHANNEL:
  650. ieee80211_scan_state_set_channel(local, &next_delay);
  651. break;
  652. case SCAN_SEND_PROBE:
  653. ieee80211_scan_state_send_probe(local, &next_delay);
  654. break;
  655. case SCAN_SUSPEND:
  656. ieee80211_scan_state_suspend(local, &next_delay);
  657. break;
  658. case SCAN_RESUME:
  659. ieee80211_scan_state_resume(local, &next_delay);
  660. break;
  661. }
  662. } while (next_delay == 0);
  663. ieee80211_queue_delayed_work(&local->hw, &local->scan_work, next_delay);
  664. goto out;
  665. out_complete:
  666. hw_scan = test_bit(SCAN_HW_SCANNING, &local->scanning);
  667. __ieee80211_scan_completed(&local->hw, aborted, hw_scan);
  668. out:
  669. mutex_unlock(&local->mtx);
  670. }
  671. int ieee80211_request_scan(struct ieee80211_sub_if_data *sdata,
  672. struct cfg80211_scan_request *req)
  673. {
  674. int res;
  675. mutex_lock(&sdata->local->mtx);
  676. res = __ieee80211_start_scan(sdata, req);
  677. mutex_unlock(&sdata->local->mtx);
  678. return res;
  679. }
  680. int ieee80211_request_internal_scan(struct ieee80211_sub_if_data *sdata,
  681. const u8 *ssid, u8 ssid_len,
  682. struct ieee80211_channel *chan)
  683. {
  684. struct ieee80211_local *local = sdata->local;
  685. int ret = -EBUSY;
  686. enum ieee80211_band band;
  687. mutex_lock(&local->mtx);
  688. /* busy scanning */
  689. if (local->scan_req)
  690. goto unlock;
  691. /* fill internal scan request */
  692. if (!chan) {
  693. int i, nchan = 0;
  694. for (band = 0; band < IEEE80211_NUM_BANDS; band++) {
  695. if (!local->hw.wiphy->bands[band])
  696. continue;
  697. for (i = 0;
  698. i < local->hw.wiphy->bands[band]->n_channels;
  699. i++) {
  700. local->int_scan_req->channels[nchan] =
  701. &local->hw.wiphy->bands[band]->channels[i];
  702. nchan++;
  703. }
  704. }
  705. local->int_scan_req->n_channels = nchan;
  706. } else {
  707. local->int_scan_req->channels[0] = chan;
  708. local->int_scan_req->n_channels = 1;
  709. }
  710. local->int_scan_req->ssids = &local->scan_ssid;
  711. local->int_scan_req->n_ssids = 1;
  712. memcpy(local->int_scan_req->ssids[0].ssid, ssid, IEEE80211_MAX_SSID_LEN);
  713. local->int_scan_req->ssids[0].ssid_len = ssid_len;
  714. ret = __ieee80211_start_scan(sdata, sdata->local->int_scan_req);
  715. unlock:
  716. mutex_unlock(&local->mtx);
  717. return ret;
  718. }
  719. /*
  720. * Only call this function when a scan can't be queued -- under RTNL.
  721. */
  722. void ieee80211_scan_cancel(struct ieee80211_local *local)
  723. {
  724. /*
  725. * We are canceling software scan, or deferred scan that was not
  726. * yet really started (see __ieee80211_start_scan ).
  727. *
  728. * Regarding hardware scan:
  729. * - we can not call __ieee80211_scan_completed() as when
  730. * SCAN_HW_SCANNING bit is set this function change
  731. * local->hw_scan_req to operate on 5G band, what race with
  732. * driver which can use local->hw_scan_req
  733. *
  734. * - we can not cancel scan_work since driver can schedule it
  735. * by ieee80211_scan_completed(..., true) to finish scan
  736. *
  737. * Hence we only call the cancel_hw_scan() callback, but the low-level
  738. * driver is still responsible for calling ieee80211_scan_completed()
  739. * after the scan was completed/aborted.
  740. */
  741. mutex_lock(&local->mtx);
  742. if (!local->scan_req)
  743. goto out;
  744. if (test_bit(SCAN_HW_SCANNING, &local->scanning)) {
  745. if (local->ops->cancel_hw_scan)
  746. drv_cancel_hw_scan(local,
  747. rcu_dereference_protected(local->scan_sdata,
  748. lockdep_is_held(&local->mtx)));
  749. goto out;
  750. }
  751. /*
  752. * If the work is currently running, it must be blocked on
  753. * the mutex, but we'll set scan_sdata = NULL and it'll
  754. * simply exit once it acquires the mutex.
  755. */
  756. cancel_delayed_work(&local->scan_work);
  757. /* and clean up */
  758. __ieee80211_scan_completed(&local->hw, true, false);
  759. out:
  760. mutex_unlock(&local->mtx);
  761. }
  762. int ieee80211_request_sched_scan_start(struct ieee80211_sub_if_data *sdata,
  763. struct cfg80211_sched_scan_request *req)
  764. {
  765. struct ieee80211_local *local = sdata->local;
  766. struct ieee80211_sched_scan_ies sched_scan_ies;
  767. int ret, i;
  768. mutex_lock(&local->mtx);
  769. if (rcu_access_pointer(local->sched_scan_sdata)) {
  770. ret = -EBUSY;
  771. goto out;
  772. }
  773. if (!local->ops->sched_scan_start) {
  774. ret = -ENOTSUPP;
  775. goto out;
  776. }
  777. for (i = 0; i < IEEE80211_NUM_BANDS; i++) {
  778. if (!local->hw.wiphy->bands[i])
  779. continue;
  780. sched_scan_ies.ie[i] = kzalloc(2 + IEEE80211_MAX_SSID_LEN +
  781. local->scan_ies_len +
  782. req->ie_len,
  783. GFP_KERNEL);
  784. if (!sched_scan_ies.ie[i]) {
  785. ret = -ENOMEM;
  786. goto out_free;
  787. }
  788. sched_scan_ies.len[i] =
  789. ieee80211_build_preq_ies(local, sched_scan_ies.ie[i],
  790. req->ie, req->ie_len, i,
  791. (u32) -1, 0);
  792. }
  793. ret = drv_sched_scan_start(local, sdata, req, &sched_scan_ies);
  794. if (ret == 0)
  795. rcu_assign_pointer(local->sched_scan_sdata, sdata);
  796. out_free:
  797. while (i > 0)
  798. kfree(sched_scan_ies.ie[--i]);
  799. out:
  800. mutex_unlock(&local->mtx);
  801. return ret;
  802. }
  803. int ieee80211_request_sched_scan_stop(struct ieee80211_sub_if_data *sdata)
  804. {
  805. struct ieee80211_local *local = sdata->local;
  806. int ret = 0;
  807. mutex_lock(&local->mtx);
  808. if (!local->ops->sched_scan_stop) {
  809. ret = -ENOTSUPP;
  810. goto out;
  811. }
  812. if (rcu_access_pointer(local->sched_scan_sdata))
  813. drv_sched_scan_stop(local, sdata);
  814. out:
  815. mutex_unlock(&local->mtx);
  816. return ret;
  817. }
  818. void ieee80211_sched_scan_results(struct ieee80211_hw *hw)
  819. {
  820. struct ieee80211_local *local = hw_to_local(hw);
  821. trace_api_sched_scan_results(local);
  822. cfg80211_sched_scan_results(hw->wiphy);
  823. }
  824. EXPORT_SYMBOL(ieee80211_sched_scan_results);
  825. void ieee80211_sched_scan_stopped_work(struct work_struct *work)
  826. {
  827. struct ieee80211_local *local =
  828. container_of(work, struct ieee80211_local,
  829. sched_scan_stopped_work);
  830. mutex_lock(&local->mtx);
  831. if (!rcu_access_pointer(local->sched_scan_sdata)) {
  832. mutex_unlock(&local->mtx);
  833. return;
  834. }
  835. rcu_assign_pointer(local->sched_scan_sdata, NULL);
  836. mutex_unlock(&local->mtx);
  837. cfg80211_sched_scan_stopped(local->hw.wiphy);
  838. }
  839. void ieee80211_sched_scan_stopped(struct ieee80211_hw *hw)
  840. {
  841. struct ieee80211_local *local = hw_to_local(hw);
  842. trace_api_sched_scan_stopped(local);
  843. ieee80211_queue_work(&local->hw, &local->sched_scan_stopped_work);
  844. }
  845. EXPORT_SYMBOL(ieee80211_sched_scan_stopped);