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
31static 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
53static 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
64static 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
76static 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
90static 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
97static 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
119static 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
129static 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
145static 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
169void 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
249void 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
299int ap_list_init(struct hostapd_iface *iface)
300{
301	return 0;
302}
303
304
305void ap_list_deinit(struct hostapd_iface *iface)
306{
307	hostapd_free_aps(iface);
308}
309