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 software may be distributed under the terms of the BSD license.
8  * See README for more details.
9  */
10 
11 #include "utils/includes.h"
12 
13 #include "utils/common.h"
14 #include "utils/eloop.h"
15 #include "common/ieee802_11_defs.h"
16 #include "common/ieee802_11_common.h"
17 #include "hostapd.h"
18 #include "ap_config.h"
19 #include "ieee802_11.h"
20 #include "sta_info.h"
21 #include "beacon.h"
22 #include "ap_list.h"
23 
24 
25 /* AP list is a double linked list with head->prev pointing to the end of the
26  * list and tail->next = NULL. Entries are moved to the head of the list
27  * whenever a beacon has been received from the AP in question. The tail entry
28  * in this link will thus be the least recently used entry. */
29 
30 
31 static int ap_list_beacon_olbc(struct hostapd_iface *iface, struct ap_info *ap)
32 {
33 	int i;
34 
35 	if (iface->current_mode == NULL ||
36 	    iface->current_mode->mode != HOSTAPD_MODE_IEEE80211G ||
37 	    iface->conf->channel != ap->channel)
38 		return 0;
39 
40 	if (ap->erp != -1 && (ap->erp & ERP_INFO_NON_ERP_PRESENT))
41 		return 1;
42 
43 	for (i = 0; i < WLAN_SUPP_RATES_MAX; i++) {
44 		int rate = (ap->supported_rates[i] & 0x7f) * 5;
45 		if (rate == 60 || rate == 90 || rate > 110)
46 			return 0;
47 	}
48 
49 	return 1;
50 }
51 
52 
53 static struct ap_info * ap_get_ap(struct hostapd_iface *iface, const u8 *ap)
54 {
55 	struct ap_info *s;
56 
57 	s = iface->ap_hash[STA_HASH(ap)];
58 	while (s != NULL && os_memcmp(s->addr, ap, ETH_ALEN) != 0)
59 		s = s->hnext;
60 	return s;
61 }
62 
63 
64 static void ap_ap_list_add(struct hostapd_iface *iface, struct ap_info *ap)
65 {
66 	if (iface->ap_list) {
67 		ap->prev = iface->ap_list->prev;
68 		iface->ap_list->prev = ap;
69 	} else
70 		ap->prev = ap;
71 	ap->next = iface->ap_list;
72 	iface->ap_list = ap;
73 }
74 
75 
76 static void ap_ap_list_del(struct hostapd_iface *iface, struct ap_info *ap)
77 {
78 	if (iface->ap_list == ap)
79 		iface->ap_list = ap->next;
80 	else
81 		ap->prev->next = ap->next;
82 
83 	if (ap->next)
84 		ap->next->prev = ap->prev;
85 	else if (iface->ap_list)
86 		iface->ap_list->prev = ap->prev;
87 }
88 
89 
90 static void ap_ap_hash_add(struct hostapd_iface *iface, struct ap_info *ap)
91 {
92 	ap->hnext = iface->ap_hash[STA_HASH(ap->addr)];
93 	iface->ap_hash[STA_HASH(ap->addr)] = ap;
94 }
95 
96 
97 static void ap_ap_hash_del(struct hostapd_iface *iface, struct ap_info *ap)
98 {
99 	struct ap_info *s;
100 
101 	s = iface->ap_hash[STA_HASH(ap->addr)];
102 	if (s == NULL) return;
103 	if (os_memcmp(s->addr, ap->addr, ETH_ALEN) == 0) {
104 		iface->ap_hash[STA_HASH(ap->addr)] = s->hnext;
105 		return;
106 	}
107 
108 	while (s->hnext != NULL &&
109 	       os_memcmp(s->hnext->addr, ap->addr, ETH_ALEN) != 0)
110 		s = s->hnext;
111 	if (s->hnext != NULL)
112 		s->hnext = s->hnext->hnext;
113 	else
114 		wpa_printf(MSG_INFO, "AP: could not remove AP " MACSTR
115 			   " from hash table",  MAC2STR(ap->addr));
116 }
117 
118 
119 static void ap_free_ap(struct hostapd_iface *iface, struct ap_info *ap)
120 {
121 	ap_ap_hash_del(iface, ap);
122 	ap_ap_list_del(iface, ap);
123 
124 	iface->num_ap--;
125 	os_free(ap);
126 }
127 
128 
129 static void hostapd_free_aps(struct hostapd_iface *iface)
130 {
131 	struct ap_info *ap, *prev;
132 
133 	ap = iface->ap_list;
134 
135 	while (ap) {
136 		prev = ap;
137 		ap = ap->next;
138 		ap_free_ap(iface, prev);
139 	}
140 
141 	iface->ap_list = NULL;
142 }
143 
144 
145 static struct ap_info * ap_ap_add(struct hostapd_iface *iface, const u8 *addr)
146 {
147 	struct ap_info *ap;
148 
149 	ap = os_zalloc(sizeof(struct ap_info));
150 	if (ap == NULL)
151 		return NULL;
152 
153 	/* initialize AP info data */
154 	os_memcpy(ap->addr, addr, ETH_ALEN);
155 	ap_ap_list_add(iface, ap);
156 	iface->num_ap++;
157 	ap_ap_hash_add(iface, ap);
158 
159 	if (iface->num_ap > iface->conf->ap_table_max_size && ap != ap->prev) {
160 		wpa_printf(MSG_DEBUG, "Removing the least recently used AP "
161 			   MACSTR " from AP table", MAC2STR(ap->prev->addr));
162 		ap_free_ap(iface, ap->prev);
163 	}
164 
165 	return ap;
166 }
167 
168 
169 void ap_list_process_beacon(struct hostapd_iface *iface,
170 			    const struct ieee80211_mgmt *mgmt,
171 			    struct ieee802_11_elems *elems,
172 			    struct hostapd_frame_info *fi)
173 {
174 	struct ap_info *ap;
175 	int new_ap = 0;
176 	int set_beacon = 0;
177 
178 	if (iface->conf->ap_table_max_size < 1)
179 		return;
180 
181 	ap = ap_get_ap(iface, mgmt->bssid);
182 	if (!ap) {
183 		ap = ap_ap_add(iface, mgmt->bssid);
184 		if (!ap) {
185 			wpa_printf(MSG_INFO,
186 				   "Failed to allocate AP information entry");
187 			return;
188 		}
189 		new_ap = 1;
190 	}
191 
192 	merge_byte_arrays(ap->supported_rates, WLAN_SUPP_RATES_MAX,
193 			  elems->supp_rates, elems->supp_rates_len,
194 			  elems->ext_supp_rates, elems->ext_supp_rates_len);
195 
196 	if (elems->erp_info)
197 		ap->erp = elems->erp_info[0];
198 	else
199 		ap->erp = -1;
200 
201 	if (elems->ds_params)
202 		ap->channel = elems->ds_params[0];
203 	else if (elems->ht_operation)
204 		ap->channel = elems->ht_operation[0];
205 	else if (fi)
206 		ap->channel = fi->channel;
207 
208 	if (elems->ht_capabilities)
209 		ap->ht_support = 1;
210 	else
211 		ap->ht_support = 0;
212 
213 	os_get_reltime(&ap->last_beacon);
214 
215 	if (!new_ap && ap != iface->ap_list) {
216 		/* move AP entry into the beginning of the list so that the
217 		 * oldest entry is always in the end of the list */
218 		ap_ap_list_del(iface, ap);
219 		ap_ap_list_add(iface, ap);
220 	}
221 
222 	if (!iface->olbc &&
223 	    ap_list_beacon_olbc(iface, ap)) {
224 		iface->olbc = 1;
225 		wpa_printf(MSG_DEBUG, "OLBC AP detected: " MACSTR
226 			   " (channel %d) - enable protection",
227 			   MAC2STR(ap->addr), ap->channel);
228 		set_beacon++;
229 	}
230 
231 #ifdef CONFIG_IEEE80211N
232 	if (!iface->olbc_ht && !ap->ht_support &&
233 	    (ap->channel == 0 ||
234 	     ap->channel == iface->conf->channel ||
235 	     ap->channel == iface->conf->channel +
236 	     iface->conf->secondary_channel * 4)) {
237 		iface->olbc_ht = 1;
238 		hostapd_ht_operation_update(iface);
239 		wpa_printf(MSG_DEBUG, "OLBC HT AP detected: " MACSTR
240 			   " (channel %d) - enable protection",
241 			   MAC2STR(ap->addr), ap->channel);
242 		set_beacon++;
243 	}
244 #endif /* CONFIG_IEEE80211N */
245 
246 	if (set_beacon)
247 		ieee802_11_update_beacons(iface);
248 }
249 
250 
251 void ap_list_timer(struct hostapd_iface *iface)
252 {
253 	struct os_reltime now;
254 	struct ap_info *ap;
255 	int set_beacon = 0;
256 
257 	if (!iface->ap_list)
258 		return;
259 
260 	os_get_reltime(&now);
261 
262 	while (iface->ap_list) {
263 		ap = iface->ap_list->prev;
264 		if (!os_reltime_expired(&now, &ap->last_beacon,
265 					iface->conf->ap_table_expiration_time))
266 			break;
267 
268 		ap_free_ap(iface, ap);
269 	}
270 
271 	if (iface->olbc || iface->olbc_ht) {
272 		int olbc = 0;
273 		int olbc_ht = 0;
274 
275 		ap = iface->ap_list;
276 		while (ap && (olbc == 0 || olbc_ht == 0)) {
277 			if (ap_list_beacon_olbc(iface, ap))
278 				olbc = 1;
279 			if (!ap->ht_support)
280 				olbc_ht = 1;
281 			ap = ap->next;
282 		}
283 		if (!olbc && iface->olbc) {
284 			wpa_printf(MSG_DEBUG, "OLBC not detected anymore");
285 			iface->olbc = 0;
286 			set_beacon++;
287 		}
288 #ifdef CONFIG_IEEE80211N
289 		if (!olbc_ht && iface->olbc_ht) {
290 			wpa_printf(MSG_DEBUG, "OLBC HT not detected anymore");
291 			iface->olbc_ht = 0;
292 			hostapd_ht_operation_update(iface);
293 			set_beacon++;
294 		}
295 #endif /* CONFIG_IEEE80211N */
296 	}
297 
298 	if (set_beacon)
299 		ieee802_11_update_beacons(iface);
300 }
301 
302 
303 int ap_list_init(struct hostapd_iface *iface)
304 {
305 	return 0;
306 }
307 
308 
309 void ap_list_deinit(struct hostapd_iface *iface)
310 {
311 	hostapd_free_aps(iface);
312 }
313