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	int new_ap = 0;
231	size_t len;
232	int set_beacon = 0;
233
234	if (iface->conf->ap_table_max_size < 1)
235		return;
236
237	ap = ap_get_ap(iface, mgmt->bssid);
238	if (!ap) {
239		ap = ap_ap_add(iface, mgmt->bssid);
240		if (!ap) {
241			printf("Failed to allocate AP information entry\n");
242			return;
243		}
244		new_ap = 1;
245	}
246
247	ap->beacon_int = le_to_host16(mgmt->u.beacon.beacon_int);
248	ap->capability = le_to_host16(mgmt->u.beacon.capab_info);
249
250	if (elems->ssid) {
251		len = elems->ssid_len;
252		if (len >= sizeof(ap->ssid))
253			len = sizeof(ap->ssid) - 1;
254		os_memcpy(ap->ssid, elems->ssid, len);
255		ap->ssid[len] = '\0';
256		ap->ssid_len = len;
257	}
258
259	os_memset(ap->supported_rates, 0, WLAN_SUPP_RATES_MAX);
260	len = 0;
261	if (elems->supp_rates) {
262		len = elems->supp_rates_len;
263		if (len > WLAN_SUPP_RATES_MAX)
264			len = WLAN_SUPP_RATES_MAX;
265		os_memcpy(ap->supported_rates, elems->supp_rates, len);
266	}
267	if (elems->ext_supp_rates) {
268		int len2;
269		if (len + elems->ext_supp_rates_len > WLAN_SUPP_RATES_MAX)
270			len2 = WLAN_SUPP_RATES_MAX - len;
271		else
272			len2 = elems->ext_supp_rates_len;
273		os_memcpy(ap->supported_rates + len, elems->ext_supp_rates,
274			  len2);
275	}
276
277	ap->wpa = elems->wpa_ie != NULL;
278
279	if (elems->erp_info && elems->erp_info_len == 1)
280		ap->erp = elems->erp_info[0];
281	else
282		ap->erp = -1;
283
284	if (elems->ds_params && elems->ds_params_len == 1)
285		ap->channel = elems->ds_params[0];
286	else if (fi)
287		ap->channel = fi->channel;
288
289	if (elems->ht_capabilities)
290		ap->ht_support = 1;
291	else
292		ap->ht_support = 0;
293
294	ap->num_beacons++;
295	time(&ap->last_beacon);
296	if (fi) {
297		ap->ssi_signal = fi->ssi_signal;
298		ap->datarate = fi->datarate;
299	}
300
301	if (!new_ap && ap != iface->ap_list) {
302		/* move AP entry into the beginning of the list so that the
303		 * oldest entry is always in the end of the list */
304		ap_ap_list_del(iface, ap);
305		ap_ap_list_add(iface, ap);
306	}
307
308	if (!iface->olbc &&
309	    ap_list_beacon_olbc(iface, ap)) {
310		iface->olbc = 1;
311		wpa_printf(MSG_DEBUG, "OLBC AP detected: " MACSTR " - enable "
312			   "protection", MAC2STR(ap->addr));
313		set_beacon++;
314	}
315
316#ifdef CONFIG_IEEE80211N
317	if (!iface->olbc_ht && !ap->ht_support) {
318		iface->olbc_ht = 1;
319		hostapd_ht_operation_update(iface);
320		wpa_printf(MSG_DEBUG, "OLBC HT AP detected: " MACSTR
321			   " - enable protection", MAC2STR(ap->addr));
322		set_beacon++;
323	}
324#endif /* CONFIG_IEEE80211N */
325
326	if (set_beacon)
327		ieee802_11_set_beacons(iface);
328}
329
330
331static void ap_list_timer(void *eloop_ctx, void *timeout_ctx)
332{
333	struct hostapd_iface *iface = eloop_ctx;
334	time_t now;
335	struct ap_info *ap;
336	int set_beacon = 0;
337
338	eloop_register_timeout(10, 0, ap_list_timer, iface, NULL);
339
340	if (!iface->ap_list)
341		return;
342
343	time(&now);
344
345	while (iface->ap_list) {
346		ap = iface->ap_list->prev;
347		if (ap->last_beacon + iface->conf->ap_table_expiration_time >=
348		    now)
349			break;
350
351		ap_free_ap(iface, ap);
352	}
353
354	if (iface->olbc || iface->olbc_ht) {
355		int olbc = 0;
356		int olbc_ht = 0;
357
358		ap = iface->ap_list;
359		while (ap && (olbc == 0 || olbc_ht == 0)) {
360			if (ap_list_beacon_olbc(iface, ap))
361				olbc = 1;
362			if (!ap->ht_support)
363				olbc_ht = 1;
364			ap = ap->next;
365		}
366		if (!olbc && iface->olbc) {
367			wpa_printf(MSG_DEBUG, "OLBC not detected anymore");
368			iface->olbc = 0;
369			set_beacon++;
370		}
371#ifdef CONFIG_IEEE80211N
372		if (!olbc_ht && iface->olbc_ht) {
373			wpa_printf(MSG_DEBUG, "OLBC HT not detected anymore");
374			iface->olbc_ht = 0;
375			hostapd_ht_operation_update(iface);
376			set_beacon++;
377		}
378#endif /* CONFIG_IEEE80211N */
379	}
380
381	if (set_beacon)
382		ieee802_11_set_beacons(iface);
383}
384
385
386int ap_list_init(struct hostapd_iface *iface)
387{
388	eloop_register_timeout(10, 0, ap_list_timer, iface, NULL);
389	return 0;
390}
391
392
393void ap_list_deinit(struct hostapd_iface *iface)
394{
395	eloop_cancel_timeout(ap_list_timer, iface, NULL);
396	hostapd_free_aps(iface);
397}
398