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
ap_list_beacon_olbc(struct hostapd_iface * iface,struct ap_info * ap)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
ap_get_ap(struct hostapd_iface * iface,const u8 * ap)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
ap_ap_list_add(struct hostapd_iface * iface,struct ap_info * ap)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
ap_ap_list_del(struct hostapd_iface * iface,struct ap_info * ap)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
ap_ap_hash_add(struct hostapd_iface * iface,struct ap_info * ap)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
ap_ap_hash_del(struct hostapd_iface * iface,struct ap_info * ap)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
ap_free_ap(struct hostapd_iface * iface,struct ap_info * ap)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
hostapd_free_aps(struct hostapd_iface * iface)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
ap_ap_add(struct hostapd_iface * iface,const u8 * addr)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
ap_list_process_beacon(struct hostapd_iface * iface,const struct ieee80211_mgmt * mgmt,struct ieee802_11_elems * elems,struct hostapd_frame_info * fi)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
ap_list_timer(struct hostapd_iface * iface)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
ap_list_init(struct hostapd_iface * iface)303 int ap_list_init(struct hostapd_iface *iface)
304 {
305 return 0;
306 }
307
308
ap_list_deinit(struct hostapd_iface * iface)309 void ap_list_deinit(struct hostapd_iface *iface)
310 {
311 hostapd_free_aps(iface);
312 }
313