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 if (!iface->olbc_ht && !ap->ht_support &&
232 (ap->channel == 0 ||
233 ap->channel == iface->conf->channel ||
234 ap->channel == iface->conf->channel +
235 iface->conf->secondary_channel * 4)) {
236 iface->olbc_ht = 1;
237 hostapd_ht_operation_update(iface);
238 wpa_printf(MSG_DEBUG, "OLBC HT AP detected: " MACSTR
239 " (channel %d) - enable protection",
240 MAC2STR(ap->addr), ap->channel);
241 set_beacon++;
242 }
243
244 if (set_beacon)
245 ieee802_11_update_beacons(iface);
246 }
247
248
ap_list_timer(struct hostapd_iface * iface)249 void ap_list_timer(struct hostapd_iface *iface)
250 {
251 struct os_reltime now;
252 struct ap_info *ap;
253 int set_beacon = 0;
254
255 if (!iface->ap_list)
256 return;
257
258 os_get_reltime(&now);
259
260 while (iface->ap_list) {
261 ap = iface->ap_list->prev;
262 if (!os_reltime_expired(&now, &ap->last_beacon,
263 iface->conf->ap_table_expiration_time))
264 break;
265
266 ap_free_ap(iface, ap);
267 }
268
269 if (iface->olbc || iface->olbc_ht) {
270 int olbc = 0;
271 int olbc_ht = 0;
272
273 ap = iface->ap_list;
274 while (ap && (olbc == 0 || olbc_ht == 0)) {
275 if (ap_list_beacon_olbc(iface, ap))
276 olbc = 1;
277 if (!ap->ht_support)
278 olbc_ht = 1;
279 ap = ap->next;
280 }
281 if (!olbc && iface->olbc) {
282 wpa_printf(MSG_DEBUG, "OLBC not detected anymore");
283 iface->olbc = 0;
284 set_beacon++;
285 }
286 if (!olbc_ht && iface->olbc_ht) {
287 wpa_printf(MSG_DEBUG, "OLBC HT not detected anymore");
288 iface->olbc_ht = 0;
289 hostapd_ht_operation_update(iface);
290 set_beacon++;
291 }
292 }
293
294 if (set_beacon)
295 ieee802_11_update_beacons(iface);
296 }
297
298
ap_list_init(struct hostapd_iface * iface)299 int ap_list_init(struct hostapd_iface *iface)
300 {
301 return 0;
302 }
303
304
ap_list_deinit(struct hostapd_iface * iface)305 void ap_list_deinit(struct hostapd_iface *iface)
306 {
307 hostapd_free_aps(iface);
308 }
309