ap_list.c revision 8d520ff1dc2da35cdca849e982051b86468016d8 
1/*
2 * hostapd / AP table
3 * Copyright (c) 2002-2009, Jouni Malinen <j@w1.fi>
4 * Copyright (c) 2003-2004, Instant802 Networks, Inc.
5 * Copyright (c) 2006, Devicescape Software, Inc.
6 *
7 * This program is free software; you can redistribute it and/or modify
8 * it under the terms of the GNU General Public License version 2 as
9 * published by the Free Software Foundation.
10 *
11 * Alternatively, this software may be distributed under the terms of BSD
12 * license.
13 *
14 * See README and COPYING for more details.
15 */
16
17#include "utils/includes.h"
18
19#include "utils/common.h"
20#include "utils/eloop.h"
21#include "common/ieee802_11_defs.h"
22#include "common/ieee802_11_common.h"
23#include "drivers/driver.h"
24#include "hostapd.h"
25#include "ap_config.h"
26#include "ieee802_11.h"
27#include "sta_info.h"
28#include "beacon.h"
29#include "ap_list.h"
30
31
32/* AP list is a double linked list with head->prev pointing to the end of the
33 * list and tail->next = NULL. Entries are moved to the head of the list
34 * whenever a beacon has been received from the AP in question. The tail entry
35 * in this link will thus be the least recently used entry. */
36
37
38static int ap_list_beacon_olbc(struct hostapd_iface *iface, struct ap_info *ap)
39{
40	int i;
41
42	if (iface->current_mode->mode != HOSTAPD_MODE_IEEE80211G ||
43	    iface->conf->channel != ap->channel)
44		return 0;
45
46	if (ap->erp != -1 && (ap->erp & ERP_INFO_NON_ERP_PRESENT))
47		return 1;
48
49	for (i = 0; i < WLAN_SUPP_RATES_MAX; i++) {
50		int rate = (ap->supported_rates[i] & 0x7f) * 5;
51		if (rate == 60 || rate == 90 || rate > 110)
52			return 0;
53	}
54
55	return 1;
56}
57
58
59struct ap_info * ap_get_ap(struct hostapd_iface *iface, const u8 *ap)
60{
61	struct ap_info *s;
62
63	s = iface->ap_hash[STA_HASH(ap)];
64	while (s != NULL && os_memcmp(s->addr, ap, ETH_ALEN) != 0)
65		s = s->hnext;
66	return s;
67}
68
69
70static void ap_ap_list_add(struct hostapd_iface *iface, struct ap_info *ap)
71{
72	if (iface->ap_list) {
73		ap->prev = iface->ap_list->prev;
74		iface->ap_list->prev = ap;
75	} else
76		ap->prev = ap;
77	ap->next = iface->ap_list;
78	iface->ap_list = ap;
79}
80
81
82static void ap_ap_list_del(struct hostapd_iface *iface, struct ap_info *ap)
83{
84	if (iface->ap_list == ap)
85		iface->ap_list = ap->next;
86	else
87		ap->prev->next = ap->next;
88
89	if (ap->next)
90		ap->next->prev = ap->prev;
91	else if (iface->ap_list)
92		iface->ap_list->prev = ap->prev;
93}
94
95
96static void ap_ap_iter_list_add(struct hostapd_iface *iface,
97				struct ap_info *ap)
98{
99	if (iface->ap_iter_list) {
100		ap->iter_prev = iface->ap_iter_list->iter_prev;
101		iface->ap_iter_list->iter_prev = ap;
102	} else
103		ap->iter_prev = ap;
104	ap->iter_next = iface->ap_iter_list;
105	iface->ap_iter_list = ap;
106}
107
108
109static void ap_ap_iter_list_del(struct hostapd_iface *iface,
110				struct ap_info *ap)
111{
112	if (iface->ap_iter_list == ap)
113		iface->ap_iter_list = ap->iter_next;
114	else
115		ap->iter_prev->iter_next = ap->iter_next;
116
117	if (ap->iter_next)
118		ap->iter_next->iter_prev = ap->iter_prev;
119	else if (iface->ap_iter_list)
120		iface->ap_iter_list->iter_prev = ap->iter_prev;
121}
122
123
124static void ap_ap_hash_add(struct hostapd_iface *iface, struct ap_info *ap)
125{
126	ap->hnext = iface->ap_hash[STA_HASH(ap->addr)];
127	iface->ap_hash[STA_HASH(ap->addr)] = ap;
128}
129
130
131static void ap_ap_hash_del(struct hostapd_iface *iface, struct ap_info *ap)
132{
133	struct ap_info *s;
134
135	s = iface->ap_hash[STA_HASH(ap->addr)];
136	if (s == NULL) return;
137	if (os_memcmp(s->addr, ap->addr, ETH_ALEN) == 0) {
138		iface->ap_hash[STA_HASH(ap->addr)] = s->hnext;
139		return;
140	}
141
142	while (s->hnext != NULL &&
143	       os_memcmp(s->hnext->addr, ap->addr, ETH_ALEN) != 0)
144		s = s->hnext;
145	if (s->hnext != NULL)
146		s->hnext = s->hnext->hnext;
147	else
148		printf("AP: could not remove AP " MACSTR " from hash table\n",
149		       MAC2STR(ap->addr));
150}
151
152
153static void ap_free_ap(struct hostapd_iface *iface, struct ap_info *ap)
154{
155	ap_ap_hash_del(iface, ap);
156	ap_ap_list_del(iface, ap);
157	ap_ap_iter_list_del(iface, ap);
158
159	iface->num_ap--;
160	os_free(ap);
161}
162
163
164static void hostapd_free_aps(struct hostapd_iface *iface)
165{
166	struct ap_info *ap, *prev;
167
168	ap = iface->ap_list;
169
170	while (ap) {
171		prev = ap;
172		ap = ap->next;
173		ap_free_ap(iface, prev);
174	}
175
176	iface->ap_list = NULL;
177}
178
179
180int ap_ap_for_each(struct hostapd_iface *iface,
181		   int (*func)(struct ap_info *s, void *data), void *data)
182{
183	struct ap_info *s;
184	int ret = 0;
185
186	s = iface->ap_list;
187
188	while (s) {
189		ret = func(s, data);
190		if (ret)
191			break;
192		s = s->next;
193	}
194
195	return ret;
196}
197
198
199static struct ap_info * ap_ap_add(struct hostapd_iface *iface, const u8 *addr)
200{
201	struct ap_info *ap;
202
203	ap = os_zalloc(sizeof(struct ap_info));
204	if (ap == NULL)
205		return NULL;
206
207	/* initialize AP info data */
208	os_memcpy(ap->addr, addr, ETH_ALEN);
209	ap_ap_list_add(iface, ap);
210	iface->num_ap++;
211	ap_ap_hash_add(iface, ap);
212	ap_ap_iter_list_add(iface, ap);
213
214	if (iface->num_ap > iface->conf->ap_table_max_size && ap != ap->prev) {
215		wpa_printf(MSG_DEBUG, "Removing the least recently used AP "
216			   MACSTR " from AP table", MAC2STR(ap->prev->addr));
217		ap_free_ap(iface, ap->prev);
218	}
219
220	return ap;
221}
222
223
224void ap_list_process_beacon(struct hostapd_iface *iface,
225			    const struct ieee80211_mgmt *mgmt,
226			    struct ieee802_11_elems *elems,
227			    struct hostapd_frame_info *fi)
228{
229	struct ap_info *ap;
230	struct os_time now;
231	int new_ap = 0;
232	size_t len;
233	int set_beacon = 0;
234
235	if (iface->conf->ap_table_max_size < 1)
236		return;
237
238	ap = ap_get_ap(iface, mgmt->bssid);
239	if (!ap) {
240		ap = ap_ap_add(iface, mgmt->bssid);
241		if (!ap) {
242			printf("Failed to allocate AP information entry\n");
243			return;
244		}
245		new_ap = 1;
246	}
247
248	ap->beacon_int = le_to_host16(mgmt->u.beacon.beacon_int);
249	ap->capability = le_to_host16(mgmt->u.beacon.capab_info);
250
251	if (elems->ssid) {
252		len = elems->ssid_len;
253		if (len >= sizeof(ap->ssid))
254			len = sizeof(ap->ssid) - 1;
255		os_memcpy(ap->ssid, elems->ssid, len);
256		ap->ssid[len] = '\0';
257		ap->ssid_len = len;
258	}
259
260	os_memset(ap->supported_rates, 0, WLAN_SUPP_RATES_MAX);
261	len = 0;
262	if (elems->supp_rates) {
263		len = elems->supp_rates_len;
264		if (len > WLAN_SUPP_RATES_MAX)
265			len = WLAN_SUPP_RATES_MAX;
266		os_memcpy(ap->supported_rates, elems->supp_rates, len);
267	}
268	if (elems->ext_supp_rates) {
269		int len2;
270		if (len + elems->ext_supp_rates_len > WLAN_SUPP_RATES_MAX)
271			len2 = WLAN_SUPP_RATES_MAX - len;
272		else
273			len2 = elems->ext_supp_rates_len;
274		os_memcpy(ap->supported_rates + len, elems->ext_supp_rates,
275			  len2);
276	}
277
278	ap->wpa = elems->wpa_ie != NULL;
279
280	if (elems->erp_info && elems->erp_info_len == 1)
281		ap->erp = elems->erp_info[0];
282	else
283		ap->erp = -1;
284
285	if (elems->ds_params && elems->ds_params_len == 1)
286		ap->channel = elems->ds_params[0];
287	else if (fi)
288		ap->channel = fi->channel;
289
290	if (elems->ht_capabilities)
291		ap->ht_support = 1;
292	else
293		ap->ht_support = 0;
294
295	ap->num_beacons++;
296	os_get_time(&now);
297	ap->last_beacon = now.sec;
298	if (fi) {
299		ap->ssi_signal = fi->ssi_signal;
300		ap->datarate = fi->datarate;
301	}
302
303	if (!new_ap && ap != iface->ap_list) {
304		/* move AP entry into the beginning of the list so that the
305		 * oldest entry is always in the end of the list */
306		ap_ap_list_del(iface, ap);
307		ap_ap_list_add(iface, ap);
308	}
309
310	if (!iface->olbc &&
311	    ap_list_beacon_olbc(iface, ap)) {
312		iface->olbc = 1;
313		wpa_printf(MSG_DEBUG, "OLBC AP detected: " MACSTR " - enable "
314			   "protection", MAC2STR(ap->addr));
315		set_beacon++;
316	}
317
318#ifdef CONFIG_IEEE80211N
319	if (!iface->olbc_ht && !ap->ht_support) {
320		iface->olbc_ht = 1;
321		hostapd_ht_operation_update(iface);
322		wpa_printf(MSG_DEBUG, "OLBC HT AP detected: " MACSTR
323			   " - enable protection", MAC2STR(ap->addr));
324		set_beacon++;
325	}
326#endif /* CONFIG_IEEE80211N */
327
328	if (set_beacon)
329		ieee802_11_set_beacons(iface);
330}
331
332
333static void ap_list_timer(void *eloop_ctx, void *timeout_ctx)
334{
335	struct hostapd_iface *iface = eloop_ctx;
336	struct os_time now;
337	struct ap_info *ap;
338	int set_beacon = 0;
339
340	eloop_register_timeout(10, 0, ap_list_timer, iface, NULL);
341
342	if (!iface->ap_list)
343		return;
344
345	os_get_time(&now);
346
347	while (iface->ap_list) {
348		ap = iface->ap_list->prev;
349		if (ap->last_beacon + iface->conf->ap_table_expiration_time >=
350		    now.sec)
351			break;
352
353		ap_free_ap(iface, ap);
354	}
355
356	if (iface->olbc || iface->olbc_ht) {
357		int olbc = 0;
358		int olbc_ht = 0;
359
360		ap = iface->ap_list;
361		while (ap && (olbc == 0 || olbc_ht == 0)) {
362			if (ap_list_beacon_olbc(iface, ap))
363				olbc = 1;
364			if (!ap->ht_support)
365				olbc_ht = 1;
366			ap = ap->next;
367		}
368		if (!olbc && iface->olbc) {
369			wpa_printf(MSG_DEBUG, "OLBC not detected anymore");
370			iface->olbc = 0;
371			set_beacon++;
372		}
373#ifdef CONFIG_IEEE80211N
374		if (!olbc_ht && iface->olbc_ht) {
375			wpa_printf(MSG_DEBUG, "OLBC HT not detected anymore");
376			iface->olbc_ht = 0;
377			hostapd_ht_operation_update(iface);
378			set_beacon++;
379		}
380#endif /* CONFIG_IEEE80211N */
381	}
382
383	if (set_beacon)
384		ieee802_11_set_beacons(iface);
385}
386
387
388int ap_list_init(struct hostapd_iface *iface)
389{
390	eloop_register_timeout(10, 0, ap_list_timer, iface, NULL);
391	return 0;
392}
393
394
395void ap_list_deinit(struct hostapd_iface *iface)
396{
397	eloop_cancel_timeout(ap_list_timer, iface, NULL);
398	hostapd_free_aps(iface);
399}
400