xref: /linux/net/wireless/scan.c (revision 67638e4043083cdc6f10386a75fef87ba46eecb3)
1 /*
2  * cfg80211 scan result handling
3  *
4  * Copyright 2008 Johannes Berg <johannes@sipsolutions.net>
5  */
6 #include <linux/kernel.h>
7 #include <linux/module.h>
8 #include <linux/netdevice.h>
9 #include <linux/wireless.h>
10 #include <linux/nl80211.h>
11 #include <linux/etherdevice.h>
12 #include <net/arp.h>
13 #include <net/cfg80211.h>
14 #include <net/iw_handler.h>
15 #include "core.h"
16 #include "nl80211.h"
17 
18 #define IEEE80211_SCAN_RESULT_EXPIRE	(10 * HZ)
19 
20 void cfg80211_scan_done(struct cfg80211_scan_request *request, bool aborted)
21 {
22 	struct net_device *dev;
23 #ifdef CONFIG_WIRELESS_EXT
24 	union iwreq_data wrqu;
25 #endif
26 
27 	dev = dev_get_by_index(&init_net, request->ifidx);
28 	if (!dev)
29 		goto out;
30 
31 	WARN_ON(request != wiphy_to_dev(request->wiphy)->scan_req);
32 
33 	if (aborted)
34 		nl80211_send_scan_aborted(wiphy_to_dev(request->wiphy), dev);
35 	else
36 		nl80211_send_scan_done(wiphy_to_dev(request->wiphy), dev);
37 
38 #ifdef CONFIG_WIRELESS_EXT
39 	if (!aborted) {
40 		memset(&wrqu, 0, sizeof(wrqu));
41 
42 		wireless_send_event(dev, SIOCGIWSCAN, &wrqu, NULL);
43 	}
44 #endif
45 
46 	dev_put(dev);
47 
48  out:
49 	wiphy_to_dev(request->wiphy)->scan_req = NULL;
50 	kfree(request);
51 }
52 EXPORT_SYMBOL(cfg80211_scan_done);
53 
54 static void bss_release(struct kref *ref)
55 {
56 	struct cfg80211_internal_bss *bss;
57 
58 	bss = container_of(ref, struct cfg80211_internal_bss, ref);
59 	if (bss->pub.free_priv)
60 		bss->pub.free_priv(&bss->pub);
61 
62 	if (bss->ies_allocated)
63 		kfree(bss->pub.information_elements);
64 
65 	kfree(bss);
66 }
67 
68 /* must hold dev->bss_lock! */
69 void cfg80211_bss_age(struct cfg80211_registered_device *dev,
70                       unsigned long age_secs)
71 {
72 	struct cfg80211_internal_bss *bss;
73 	unsigned long age_jiffies = msecs_to_jiffies(age_secs * MSEC_PER_SEC);
74 
75 	list_for_each_entry(bss, &dev->bss_list, list) {
76 		bss->ts -= age_jiffies;
77 	}
78 }
79 
80 /* must hold dev->bss_lock! */
81 void cfg80211_bss_expire(struct cfg80211_registered_device *dev)
82 {
83 	struct cfg80211_internal_bss *bss, *tmp;
84 	bool expired = false;
85 
86 	list_for_each_entry_safe(bss, tmp, &dev->bss_list, list) {
87 		if (bss->hold ||
88 		    !time_after(jiffies, bss->ts + IEEE80211_SCAN_RESULT_EXPIRE))
89 			continue;
90 		list_del(&bss->list);
91 		rb_erase(&bss->rbn, &dev->bss_tree);
92 		kref_put(&bss->ref, bss_release);
93 		expired = true;
94 	}
95 
96 	if (expired)
97 		dev->bss_generation++;
98 }
99 
100 static u8 *find_ie(u8 num, u8 *ies, size_t len)
101 {
102 	while (len > 2 && ies[0] != num) {
103 		len -= ies[1] + 2;
104 		ies += ies[1] + 2;
105 	}
106 	if (len < 2)
107 		return NULL;
108 	if (len < 2 + ies[1])
109 		return NULL;
110 	return ies;
111 }
112 
113 static int cmp_ies(u8 num, u8 *ies1, size_t len1, u8 *ies2, size_t len2)
114 {
115 	const u8 *ie1 = find_ie(num, ies1, len1);
116 	const u8 *ie2 = find_ie(num, ies2, len2);
117 	int r;
118 
119 	if (!ie1 && !ie2)
120 		return 0;
121 	if (!ie1)
122 		return -1;
123 
124 	r = memcmp(ie1 + 2, ie2 + 2, min(ie1[1], ie2[1]));
125 	if (r == 0 && ie1[1] != ie2[1])
126 		return ie2[1] - ie1[1];
127 	return r;
128 }
129 
130 static bool is_bss(struct cfg80211_bss *a,
131 		   const u8 *bssid,
132 		   const u8 *ssid, size_t ssid_len)
133 {
134 	const u8 *ssidie;
135 
136 	if (bssid && compare_ether_addr(a->bssid, bssid))
137 		return false;
138 
139 	if (!ssid)
140 		return true;
141 
142 	ssidie = find_ie(WLAN_EID_SSID,
143 			 a->information_elements,
144 			 a->len_information_elements);
145 	if (!ssidie)
146 		return false;
147 	if (ssidie[1] != ssid_len)
148 		return false;
149 	return memcmp(ssidie + 2, ssid, ssid_len) == 0;
150 }
151 
152 static bool is_mesh(struct cfg80211_bss *a,
153 		    const u8 *meshid, size_t meshidlen,
154 		    const u8 *meshcfg)
155 {
156 	const u8 *ie;
157 
158 	if (!is_zero_ether_addr(a->bssid))
159 		return false;
160 
161 	ie = find_ie(WLAN_EID_MESH_ID,
162 		     a->information_elements,
163 		     a->len_information_elements);
164 	if (!ie)
165 		return false;
166 	if (ie[1] != meshidlen)
167 		return false;
168 	if (memcmp(ie + 2, meshid, meshidlen))
169 		return false;
170 
171 	ie = find_ie(WLAN_EID_MESH_CONFIG,
172 		     a->information_elements,
173 		     a->len_information_elements);
174 	if (ie[1] != IEEE80211_MESH_CONFIG_LEN)
175 		return false;
176 
177 	/*
178 	 * Ignore mesh capability (last two bytes of the IE) when
179 	 * comparing since that may differ between stations taking
180 	 * part in the same mesh.
181 	 */
182 	return memcmp(ie + 2, meshcfg, IEEE80211_MESH_CONFIG_LEN - 2) == 0;
183 }
184 
185 static int cmp_bss(struct cfg80211_bss *a,
186 		   struct cfg80211_bss *b)
187 {
188 	int r;
189 
190 	if (a->channel != b->channel)
191 		return b->channel->center_freq - a->channel->center_freq;
192 
193 	r = memcmp(a->bssid, b->bssid, ETH_ALEN);
194 	if (r)
195 		return r;
196 
197 	if (is_zero_ether_addr(a->bssid)) {
198 		r = cmp_ies(WLAN_EID_MESH_ID,
199 			    a->information_elements,
200 			    a->len_information_elements,
201 			    b->information_elements,
202 			    b->len_information_elements);
203 		if (r)
204 			return r;
205 		return cmp_ies(WLAN_EID_MESH_CONFIG,
206 			       a->information_elements,
207 			       a->len_information_elements,
208 			       b->information_elements,
209 			       b->len_information_elements);
210 	}
211 
212 	return cmp_ies(WLAN_EID_SSID,
213 		       a->information_elements,
214 		       a->len_information_elements,
215 		       b->information_elements,
216 		       b->len_information_elements);
217 }
218 
219 struct cfg80211_bss *cfg80211_get_bss(struct wiphy *wiphy,
220 				      struct ieee80211_channel *channel,
221 				      const u8 *bssid,
222 				      const u8 *ssid, size_t ssid_len,
223 				      u16 capa_mask, u16 capa_val)
224 {
225 	struct cfg80211_registered_device *dev = wiphy_to_dev(wiphy);
226 	struct cfg80211_internal_bss *bss, *res = NULL;
227 
228 	spin_lock_bh(&dev->bss_lock);
229 
230 	list_for_each_entry(bss, &dev->bss_list, list) {
231 		if ((bss->pub.capability & capa_mask) != capa_val)
232 			continue;
233 		if (channel && bss->pub.channel != channel)
234 			continue;
235 		if (is_bss(&bss->pub, bssid, ssid, ssid_len)) {
236 			res = bss;
237 			kref_get(&res->ref);
238 			break;
239 		}
240 	}
241 
242 	spin_unlock_bh(&dev->bss_lock);
243 	if (!res)
244 		return NULL;
245 	return &res->pub;
246 }
247 EXPORT_SYMBOL(cfg80211_get_bss);
248 
249 struct cfg80211_bss *cfg80211_get_mesh(struct wiphy *wiphy,
250 				       struct ieee80211_channel *channel,
251 				       const u8 *meshid, size_t meshidlen,
252 				       const u8 *meshcfg)
253 {
254 	struct cfg80211_registered_device *dev = wiphy_to_dev(wiphy);
255 	struct cfg80211_internal_bss *bss, *res = NULL;
256 
257 	spin_lock_bh(&dev->bss_lock);
258 
259 	list_for_each_entry(bss, &dev->bss_list, list) {
260 		if (channel && bss->pub.channel != channel)
261 			continue;
262 		if (is_mesh(&bss->pub, meshid, meshidlen, meshcfg)) {
263 			res = bss;
264 			kref_get(&res->ref);
265 			break;
266 		}
267 	}
268 
269 	spin_unlock_bh(&dev->bss_lock);
270 	if (!res)
271 		return NULL;
272 	return &res->pub;
273 }
274 EXPORT_SYMBOL(cfg80211_get_mesh);
275 
276 
277 static void rb_insert_bss(struct cfg80211_registered_device *dev,
278 			  struct cfg80211_internal_bss *bss)
279 {
280 	struct rb_node **p = &dev->bss_tree.rb_node;
281 	struct rb_node *parent = NULL;
282 	struct cfg80211_internal_bss *tbss;
283 	int cmp;
284 
285 	while (*p) {
286 		parent = *p;
287 		tbss = rb_entry(parent, struct cfg80211_internal_bss, rbn);
288 
289 		cmp = cmp_bss(&bss->pub, &tbss->pub);
290 
291 		if (WARN_ON(!cmp)) {
292 			/* will sort of leak this BSS */
293 			return;
294 		}
295 
296 		if (cmp < 0)
297 			p = &(*p)->rb_left;
298 		else
299 			p = &(*p)->rb_right;
300 	}
301 
302 	rb_link_node(&bss->rbn, parent, p);
303 	rb_insert_color(&bss->rbn, &dev->bss_tree);
304 }
305 
306 static struct cfg80211_internal_bss *
307 rb_find_bss(struct cfg80211_registered_device *dev,
308 	    struct cfg80211_internal_bss *res)
309 {
310 	struct rb_node *n = dev->bss_tree.rb_node;
311 	struct cfg80211_internal_bss *bss;
312 	int r;
313 
314 	while (n) {
315 		bss = rb_entry(n, struct cfg80211_internal_bss, rbn);
316 		r = cmp_bss(&res->pub, &bss->pub);
317 
318 		if (r == 0)
319 			return bss;
320 		else if (r < 0)
321 			n = n->rb_left;
322 		else
323 			n = n->rb_right;
324 	}
325 
326 	return NULL;
327 }
328 
329 static struct cfg80211_internal_bss *
330 cfg80211_bss_update(struct cfg80211_registered_device *dev,
331 		    struct cfg80211_internal_bss *res,
332 		    bool overwrite)
333 {
334 	struct cfg80211_internal_bss *found = NULL;
335 	const u8 *meshid, *meshcfg;
336 
337 	/*
338 	 * The reference to "res" is donated to this function.
339 	 */
340 
341 	if (WARN_ON(!res->pub.channel)) {
342 		kref_put(&res->ref, bss_release);
343 		return NULL;
344 	}
345 
346 	res->ts = jiffies;
347 
348 	if (is_zero_ether_addr(res->pub.bssid)) {
349 		/* must be mesh, verify */
350 		meshid = find_ie(WLAN_EID_MESH_ID, res->pub.information_elements,
351 				 res->pub.len_information_elements);
352 		meshcfg = find_ie(WLAN_EID_MESH_CONFIG,
353 				  res->pub.information_elements,
354 				  res->pub.len_information_elements);
355 		if (!meshid || !meshcfg ||
356 		    meshcfg[1] != IEEE80211_MESH_CONFIG_LEN) {
357 			/* bogus mesh */
358 			kref_put(&res->ref, bss_release);
359 			return NULL;
360 		}
361 	}
362 
363 	spin_lock_bh(&dev->bss_lock);
364 
365 	found = rb_find_bss(dev, res);
366 
367 	if (found) {
368 		found->pub.beacon_interval = res->pub.beacon_interval;
369 		found->pub.tsf = res->pub.tsf;
370 		found->pub.signal = res->pub.signal;
371 		found->pub.capability = res->pub.capability;
372 		found->ts = res->ts;
373 
374 		/* overwrite IEs */
375 		if (overwrite) {
376 			size_t used = dev->wiphy.bss_priv_size + sizeof(*res);
377 			size_t ielen = res->pub.len_information_elements;
378 
379 			if (!found->ies_allocated && ksize(found) >= used + ielen) {
380 				memcpy(found->pub.information_elements,
381 				       res->pub.information_elements, ielen);
382 				found->pub.len_information_elements = ielen;
383 			} else {
384 				u8 *ies = found->pub.information_elements;
385 
386 				if (found->ies_allocated)
387 					ies = krealloc(ies, ielen, GFP_ATOMIC);
388 				else
389 					ies = kmalloc(ielen, GFP_ATOMIC);
390 
391 				if (ies) {
392 					memcpy(ies, res->pub.information_elements, ielen);
393 					found->ies_allocated = true;
394 					found->pub.information_elements = ies;
395 					found->pub.len_information_elements = ielen;
396 				}
397 			}
398 		}
399 
400 		kref_put(&res->ref, bss_release);
401 	} else {
402 		/* this "consumes" the reference */
403 		list_add_tail(&res->list, &dev->bss_list);
404 		rb_insert_bss(dev, res);
405 		found = res;
406 	}
407 
408 	dev->bss_generation++;
409 	spin_unlock_bh(&dev->bss_lock);
410 
411 	kref_get(&found->ref);
412 	return found;
413 }
414 
415 struct cfg80211_bss*
416 cfg80211_inform_bss(struct wiphy *wiphy,
417 		    struct ieee80211_channel *channel,
418 		    const u8 *bssid,
419 		    u64 timestamp, u16 capability, u16 beacon_interval,
420 		    const u8 *ie, size_t ielen,
421 		    s32 signal, gfp_t gfp)
422 {
423 	struct cfg80211_internal_bss *res;
424 	size_t privsz;
425 
426 	if (WARN_ON(!wiphy))
427 		return NULL;
428 
429 	privsz = wiphy->bss_priv_size;
430 
431 	if (WARN_ON(wiphy->signal_type == NL80211_BSS_SIGNAL_UNSPEC &&
432 			(signal < 0 || signal > 100)))
433 		return NULL;
434 
435 	res = kzalloc(sizeof(*res) + privsz + ielen, gfp);
436 	if (!res)
437 		return NULL;
438 
439 	memcpy(res->pub.bssid, bssid, ETH_ALEN);
440 	res->pub.channel = channel;
441 	res->pub.signal = signal;
442 	res->pub.tsf = timestamp;
443 	res->pub.beacon_interval = beacon_interval;
444 	res->pub.capability = capability;
445 	/* point to after the private area */
446 	res->pub.information_elements = (u8 *)res + sizeof(*res) + privsz;
447 	memcpy(res->pub.information_elements, ie, ielen);
448 	res->pub.len_information_elements = ielen;
449 
450 	kref_init(&res->ref);
451 
452 	res = cfg80211_bss_update(wiphy_to_dev(wiphy), res, 0);
453 	if (!res)
454 		return NULL;
455 
456 	if (res->pub.capability & WLAN_CAPABILITY_ESS)
457 		regulatory_hint_found_beacon(wiphy, channel, gfp);
458 
459 	/* cfg80211_bss_update gives us a referenced result */
460 	return &res->pub;
461 }
462 EXPORT_SYMBOL(cfg80211_inform_bss);
463 
464 struct cfg80211_bss *
465 cfg80211_inform_bss_frame(struct wiphy *wiphy,
466 			  struct ieee80211_channel *channel,
467 			  struct ieee80211_mgmt *mgmt, size_t len,
468 			  s32 signal, gfp_t gfp)
469 {
470 	struct cfg80211_internal_bss *res;
471 	size_t ielen = len - offsetof(struct ieee80211_mgmt,
472 				      u.probe_resp.variable);
473 	bool overwrite;
474 	size_t privsz = wiphy->bss_priv_size;
475 
476 	if (WARN_ON(wiphy->signal_type == NL80211_BSS_SIGNAL_UNSPEC &&
477 	            (signal < 0 || signal > 100)))
478 		return NULL;
479 
480 	if (WARN_ON(!mgmt || !wiphy ||
481 		    len < offsetof(struct ieee80211_mgmt, u.probe_resp.variable)))
482 		return NULL;
483 
484 	res = kzalloc(sizeof(*res) + privsz + ielen, gfp);
485 	if (!res)
486 		return NULL;
487 
488 	memcpy(res->pub.bssid, mgmt->bssid, ETH_ALEN);
489 	res->pub.channel = channel;
490 	res->pub.signal = signal;
491 	res->pub.tsf = le64_to_cpu(mgmt->u.probe_resp.timestamp);
492 	res->pub.beacon_interval = le16_to_cpu(mgmt->u.probe_resp.beacon_int);
493 	res->pub.capability = le16_to_cpu(mgmt->u.probe_resp.capab_info);
494 	/* point to after the private area */
495 	res->pub.information_elements = (u8 *)res + sizeof(*res) + privsz;
496 	memcpy(res->pub.information_elements, mgmt->u.probe_resp.variable, ielen);
497 	res->pub.len_information_elements = ielen;
498 
499 	kref_init(&res->ref);
500 
501 	overwrite = ieee80211_is_probe_resp(mgmt->frame_control);
502 
503 	res = cfg80211_bss_update(wiphy_to_dev(wiphy), res, overwrite);
504 	if (!res)
505 		return NULL;
506 
507 	if (res->pub.capability & WLAN_CAPABILITY_ESS)
508 		regulatory_hint_found_beacon(wiphy, channel, gfp);
509 
510 	/* cfg80211_bss_update gives us a referenced result */
511 	return &res->pub;
512 }
513 EXPORT_SYMBOL(cfg80211_inform_bss_frame);
514 
515 void cfg80211_put_bss(struct cfg80211_bss *pub)
516 {
517 	struct cfg80211_internal_bss *bss;
518 
519 	if (!pub)
520 		return;
521 
522 	bss = container_of(pub, struct cfg80211_internal_bss, pub);
523 	kref_put(&bss->ref, bss_release);
524 }
525 EXPORT_SYMBOL(cfg80211_put_bss);
526 
527 void cfg80211_unlink_bss(struct wiphy *wiphy, struct cfg80211_bss *pub)
528 {
529 	struct cfg80211_registered_device *dev = wiphy_to_dev(wiphy);
530 	struct cfg80211_internal_bss *bss;
531 
532 	if (WARN_ON(!pub))
533 		return;
534 
535 	bss = container_of(pub, struct cfg80211_internal_bss, pub);
536 
537 	spin_lock_bh(&dev->bss_lock);
538 
539 	list_del(&bss->list);
540 	rb_erase(&bss->rbn, &dev->bss_tree);
541 
542 	spin_unlock_bh(&dev->bss_lock);
543 
544 	kref_put(&bss->ref, bss_release);
545 }
546 EXPORT_SYMBOL(cfg80211_unlink_bss);
547 
548 void cfg80211_hold_bss(struct cfg80211_bss *pub)
549 {
550 	struct cfg80211_internal_bss *bss;
551 
552 	if (!pub)
553 		return;
554 
555 	bss = container_of(pub, struct cfg80211_internal_bss, pub);
556 	bss->hold = true;
557 }
558 EXPORT_SYMBOL(cfg80211_hold_bss);
559 
560 void cfg80211_unhold_bss(struct cfg80211_bss *pub)
561 {
562 	struct cfg80211_internal_bss *bss;
563 
564 	if (!pub)
565 		return;
566 
567 	bss = container_of(pub, struct cfg80211_internal_bss, pub);
568 	bss->hold = false;
569 }
570 EXPORT_SYMBOL(cfg80211_unhold_bss);
571 
572 #ifdef CONFIG_WIRELESS_EXT
573 int cfg80211_wext_siwscan(struct net_device *dev,
574 			  struct iw_request_info *info,
575 			  union iwreq_data *wrqu, char *extra)
576 {
577 	struct cfg80211_registered_device *rdev;
578 	struct wiphy *wiphy;
579 	struct iw_scan_req *wreq = NULL;
580 	struct cfg80211_scan_request *creq;
581 	int i, err, n_channels = 0;
582 	enum ieee80211_band band;
583 
584 	if (!netif_running(dev))
585 		return -ENETDOWN;
586 
587 	rdev = cfg80211_get_dev_from_ifindex(dev->ifindex);
588 
589 	if (IS_ERR(rdev))
590 		return PTR_ERR(rdev);
591 
592 	if (rdev->scan_req) {
593 		err = -EBUSY;
594 		goto out;
595 	}
596 
597 	wiphy = &rdev->wiphy;
598 
599 	for (band = 0; band < IEEE80211_NUM_BANDS; band++)
600 		if (wiphy->bands[band])
601 			n_channels += wiphy->bands[band]->n_channels;
602 
603 	creq = kzalloc(sizeof(*creq) + sizeof(struct cfg80211_ssid) +
604 		       n_channels * sizeof(void *),
605 		       GFP_ATOMIC);
606 	if (!creq) {
607 		err = -ENOMEM;
608 		goto out;
609 	}
610 
611 	creq->wiphy = wiphy;
612 	creq->ifidx = dev->ifindex;
613 	creq->ssids = (void *)(creq + 1);
614 	creq->channels = (void *)(creq->ssids + 1);
615 	creq->n_channels = n_channels;
616 	creq->n_ssids = 1;
617 
618 	/* all channels */
619 	i = 0;
620 	for (band = 0; band < IEEE80211_NUM_BANDS; band++) {
621 		int j;
622 		if (!wiphy->bands[band])
623 			continue;
624 		for (j = 0; j < wiphy->bands[band]->n_channels; j++) {
625 			creq->channels[i] = &wiphy->bands[band]->channels[j];
626 			i++;
627 		}
628 	}
629 
630 	/* translate scan request */
631 	if (wrqu->data.length == sizeof(struct iw_scan_req)) {
632 		wreq = (struct iw_scan_req *)extra;
633 
634 		if (wrqu->data.flags & IW_SCAN_THIS_ESSID) {
635 			if (wreq->essid_len > IEEE80211_MAX_SSID_LEN)
636 				return -EINVAL;
637 			memcpy(creq->ssids[0].ssid, wreq->essid, wreq->essid_len);
638 			creq->ssids[0].ssid_len = wreq->essid_len;
639 		}
640 		if (wreq->scan_type == IW_SCAN_TYPE_PASSIVE)
641 			creq->n_ssids = 0;
642 	}
643 
644 	rdev->scan_req = creq;
645 	err = rdev->ops->scan(wiphy, dev, creq);
646 	if (err) {
647 		rdev->scan_req = NULL;
648 		kfree(creq);
649 	}
650  out:
651 	cfg80211_put_dev(rdev);
652 	return err;
653 }
654 EXPORT_SYMBOL_GPL(cfg80211_wext_siwscan);
655 
656 static void ieee80211_scan_add_ies(struct iw_request_info *info,
657 				   struct cfg80211_bss *bss,
658 				   char **current_ev, char *end_buf)
659 {
660 	u8 *pos, *end, *next;
661 	struct iw_event iwe;
662 
663 	if (!bss->information_elements ||
664 	    !bss->len_information_elements)
665 		return;
666 
667 	/*
668 	 * If needed, fragment the IEs buffer (at IE boundaries) into short
669 	 * enough fragments to fit into IW_GENERIC_IE_MAX octet messages.
670 	 */
671 	pos = bss->information_elements;
672 	end = pos + bss->len_information_elements;
673 
674 	while (end - pos > IW_GENERIC_IE_MAX) {
675 		next = pos + 2 + pos[1];
676 		while (next + 2 + next[1] - pos < IW_GENERIC_IE_MAX)
677 			next = next + 2 + next[1];
678 
679 		memset(&iwe, 0, sizeof(iwe));
680 		iwe.cmd = IWEVGENIE;
681 		iwe.u.data.length = next - pos;
682 		*current_ev = iwe_stream_add_point(info, *current_ev,
683 						   end_buf, &iwe, pos);
684 
685 		pos = next;
686 	}
687 
688 	if (end > pos) {
689 		memset(&iwe, 0, sizeof(iwe));
690 		iwe.cmd = IWEVGENIE;
691 		iwe.u.data.length = end - pos;
692 		*current_ev = iwe_stream_add_point(info, *current_ev,
693 						   end_buf, &iwe, pos);
694 	}
695 }
696 
697 static inline unsigned int elapsed_jiffies_msecs(unsigned long start)
698 {
699 	unsigned long end = jiffies;
700 
701 	if (end >= start)
702 		return jiffies_to_msecs(end - start);
703 
704 	return jiffies_to_msecs(end + (MAX_JIFFY_OFFSET - start) + 1);
705 }
706 
707 static char *
708 ieee80211_bss(struct wiphy *wiphy, struct iw_request_info *info,
709 	      struct cfg80211_internal_bss *bss, char *current_ev,
710 	      char *end_buf)
711 {
712 	struct iw_event iwe;
713 	u8 *buf, *cfg, *p;
714 	u8 *ie = bss->pub.information_elements;
715 	int rem = bss->pub.len_information_elements, i, sig;
716 	bool ismesh = false;
717 
718 	memset(&iwe, 0, sizeof(iwe));
719 	iwe.cmd = SIOCGIWAP;
720 	iwe.u.ap_addr.sa_family = ARPHRD_ETHER;
721 	memcpy(iwe.u.ap_addr.sa_data, bss->pub.bssid, ETH_ALEN);
722 	current_ev = iwe_stream_add_event(info, current_ev, end_buf, &iwe,
723 					  IW_EV_ADDR_LEN);
724 
725 	memset(&iwe, 0, sizeof(iwe));
726 	iwe.cmd = SIOCGIWFREQ;
727 	iwe.u.freq.m = ieee80211_frequency_to_channel(bss->pub.channel->center_freq);
728 	iwe.u.freq.e = 0;
729 	current_ev = iwe_stream_add_event(info, current_ev, end_buf, &iwe,
730 					  IW_EV_FREQ_LEN);
731 
732 	memset(&iwe, 0, sizeof(iwe));
733 	iwe.cmd = SIOCGIWFREQ;
734 	iwe.u.freq.m = bss->pub.channel->center_freq;
735 	iwe.u.freq.e = 6;
736 	current_ev = iwe_stream_add_event(info, current_ev, end_buf, &iwe,
737 					  IW_EV_FREQ_LEN);
738 
739 	if (wiphy->signal_type != CFG80211_SIGNAL_TYPE_NONE) {
740 		memset(&iwe, 0, sizeof(iwe));
741 		iwe.cmd = IWEVQUAL;
742 		iwe.u.qual.updated = IW_QUAL_LEVEL_UPDATED |
743 				     IW_QUAL_NOISE_INVALID |
744 				     IW_QUAL_QUAL_UPDATED;
745 		switch (wiphy->signal_type) {
746 		case CFG80211_SIGNAL_TYPE_MBM:
747 			sig = bss->pub.signal / 100;
748 			iwe.u.qual.level = sig;
749 			iwe.u.qual.updated |= IW_QUAL_DBM;
750 			if (sig < -110)		/* rather bad */
751 				sig = -110;
752 			else if (sig > -40)	/* perfect */
753 				sig = -40;
754 			/* will give a range of 0 .. 70 */
755 			iwe.u.qual.qual = sig + 110;
756 			break;
757 		case CFG80211_SIGNAL_TYPE_UNSPEC:
758 			iwe.u.qual.level = bss->pub.signal;
759 			/* will give range 0 .. 100 */
760 			iwe.u.qual.qual = bss->pub.signal;
761 			break;
762 		default:
763 			/* not reached */
764 			break;
765 		}
766 		current_ev = iwe_stream_add_event(info, current_ev, end_buf,
767 						  &iwe, IW_EV_QUAL_LEN);
768 	}
769 
770 	memset(&iwe, 0, sizeof(iwe));
771 	iwe.cmd = SIOCGIWENCODE;
772 	if (bss->pub.capability & WLAN_CAPABILITY_PRIVACY)
773 		iwe.u.data.flags = IW_ENCODE_ENABLED | IW_ENCODE_NOKEY;
774 	else
775 		iwe.u.data.flags = IW_ENCODE_DISABLED;
776 	iwe.u.data.length = 0;
777 	current_ev = iwe_stream_add_point(info, current_ev, end_buf,
778 					  &iwe, "");
779 
780 	while (rem >= 2) {
781 		/* invalid data */
782 		if (ie[1] > rem - 2)
783 			break;
784 
785 		switch (ie[0]) {
786 		case WLAN_EID_SSID:
787 			memset(&iwe, 0, sizeof(iwe));
788 			iwe.cmd = SIOCGIWESSID;
789 			iwe.u.data.length = ie[1];
790 			iwe.u.data.flags = 1;
791 			current_ev = iwe_stream_add_point(info, current_ev, end_buf,
792 							  &iwe, ie + 2);
793 			break;
794 		case WLAN_EID_MESH_ID:
795 			memset(&iwe, 0, sizeof(iwe));
796 			iwe.cmd = SIOCGIWESSID;
797 			iwe.u.data.length = ie[1];
798 			iwe.u.data.flags = 1;
799 			current_ev = iwe_stream_add_point(info, current_ev, end_buf,
800 							  &iwe, ie + 2);
801 			break;
802 		case WLAN_EID_MESH_CONFIG:
803 			ismesh = true;
804 			if (ie[1] != IEEE80211_MESH_CONFIG_LEN)
805 				break;
806 			buf = kmalloc(50, GFP_ATOMIC);
807 			if (!buf)
808 				break;
809 			cfg = ie + 2;
810 			memset(&iwe, 0, sizeof(iwe));
811 			iwe.cmd = IWEVCUSTOM;
812 			sprintf(buf, "Mesh network (version %d)", cfg[0]);
813 			iwe.u.data.length = strlen(buf);
814 			current_ev = iwe_stream_add_point(info, current_ev,
815 							  end_buf,
816 							  &iwe, buf);
817 			sprintf(buf, "Path Selection Protocol ID: "
818 				"0x%02X%02X%02X%02X", cfg[1], cfg[2], cfg[3],
819 							cfg[4]);
820 			iwe.u.data.length = strlen(buf);
821 			current_ev = iwe_stream_add_point(info, current_ev,
822 							  end_buf,
823 							  &iwe, buf);
824 			sprintf(buf, "Path Selection Metric ID: "
825 				"0x%02X%02X%02X%02X", cfg[5], cfg[6], cfg[7],
826 							cfg[8]);
827 			iwe.u.data.length = strlen(buf);
828 			current_ev = iwe_stream_add_point(info, current_ev,
829 							  end_buf,
830 							  &iwe, buf);
831 			sprintf(buf, "Congestion Control Mode ID: "
832 				"0x%02X%02X%02X%02X", cfg[9], cfg[10],
833 							cfg[11], cfg[12]);
834 			iwe.u.data.length = strlen(buf);
835 			current_ev = iwe_stream_add_point(info, current_ev,
836 							  end_buf,
837 							  &iwe, buf);
838 			sprintf(buf, "Channel Precedence: "
839 				"0x%02X%02X%02X%02X", cfg[13], cfg[14],
840 							cfg[15], cfg[16]);
841 			iwe.u.data.length = strlen(buf);
842 			current_ev = iwe_stream_add_point(info, current_ev,
843 							  end_buf,
844 							  &iwe, buf);
845 			kfree(buf);
846 			break;
847 		case WLAN_EID_SUPP_RATES:
848 		case WLAN_EID_EXT_SUPP_RATES:
849 			/* display all supported rates in readable format */
850 			p = current_ev + iwe_stream_lcp_len(info);
851 
852 			memset(&iwe, 0, sizeof(iwe));
853 			iwe.cmd = SIOCGIWRATE;
854 			/* Those two flags are ignored... */
855 			iwe.u.bitrate.fixed = iwe.u.bitrate.disabled = 0;
856 
857 			for (i = 0; i < ie[1]; i++) {
858 				iwe.u.bitrate.value =
859 					((ie[i + 2] & 0x7f) * 500000);
860 				p = iwe_stream_add_value(info, current_ev, p,
861 						end_buf, &iwe, IW_EV_PARAM_LEN);
862 			}
863 			current_ev = p;
864 			break;
865 		}
866 		rem -= ie[1] + 2;
867 		ie += ie[1] + 2;
868 	}
869 
870 	if (bss->pub.capability & (WLAN_CAPABILITY_ESS | WLAN_CAPABILITY_IBSS)
871 	    || ismesh) {
872 		memset(&iwe, 0, sizeof(iwe));
873 		iwe.cmd = SIOCGIWMODE;
874 		if (ismesh)
875 			iwe.u.mode = IW_MODE_MESH;
876 		else if (bss->pub.capability & WLAN_CAPABILITY_ESS)
877 			iwe.u.mode = IW_MODE_MASTER;
878 		else
879 			iwe.u.mode = IW_MODE_ADHOC;
880 		current_ev = iwe_stream_add_event(info, current_ev, end_buf,
881 						  &iwe, IW_EV_UINT_LEN);
882 	}
883 
884 	buf = kmalloc(30, GFP_ATOMIC);
885 	if (buf) {
886 		memset(&iwe, 0, sizeof(iwe));
887 		iwe.cmd = IWEVCUSTOM;
888 		sprintf(buf, "tsf=%016llx", (unsigned long long)(bss->pub.tsf));
889 		iwe.u.data.length = strlen(buf);
890 		current_ev = iwe_stream_add_point(info, current_ev, end_buf,
891 						  &iwe, buf);
892 		memset(&iwe, 0, sizeof(iwe));
893 		iwe.cmd = IWEVCUSTOM;
894 		sprintf(buf, " Last beacon: %ums ago",
895 			elapsed_jiffies_msecs(bss->ts));
896 		iwe.u.data.length = strlen(buf);
897 		current_ev = iwe_stream_add_point(info, current_ev,
898 						  end_buf, &iwe, buf);
899 		kfree(buf);
900 	}
901 
902 	ieee80211_scan_add_ies(info, &bss->pub, &current_ev, end_buf);
903 
904 	return current_ev;
905 }
906 
907 
908 static int ieee80211_scan_results(struct cfg80211_registered_device *dev,
909 				  struct iw_request_info *info,
910 				  char *buf, size_t len)
911 {
912 	char *current_ev = buf;
913 	char *end_buf = buf + len;
914 	struct cfg80211_internal_bss *bss;
915 
916 	spin_lock_bh(&dev->bss_lock);
917 	cfg80211_bss_expire(dev);
918 
919 	list_for_each_entry(bss, &dev->bss_list, list) {
920 		if (buf + len - current_ev <= IW_EV_ADDR_LEN) {
921 			spin_unlock_bh(&dev->bss_lock);
922 			return -E2BIG;
923 		}
924 		current_ev = ieee80211_bss(&dev->wiphy, info, bss,
925 					   current_ev, end_buf);
926 	}
927 	spin_unlock_bh(&dev->bss_lock);
928 	return current_ev - buf;
929 }
930 
931 
932 int cfg80211_wext_giwscan(struct net_device *dev,
933 			  struct iw_request_info *info,
934 			  struct iw_point *data, char *extra)
935 {
936 	struct cfg80211_registered_device *rdev;
937 	int res;
938 
939 	if (!netif_running(dev))
940 		return -ENETDOWN;
941 
942 	rdev = cfg80211_get_dev_from_ifindex(dev->ifindex);
943 
944 	if (IS_ERR(rdev))
945 		return PTR_ERR(rdev);
946 
947 	if (rdev->scan_req) {
948 		res = -EAGAIN;
949 		goto out;
950 	}
951 
952 	res = ieee80211_scan_results(rdev, info, extra, data->length);
953 	data->length = 0;
954 	if (res >= 0) {
955 		data->length = res;
956 		res = 0;
957 	}
958 
959  out:
960 	cfg80211_put_dev(rdev);
961 	return res;
962 }
963 EXPORT_SYMBOL_GPL(cfg80211_wext_giwscan);
964 #endif
965