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      1 /*
      2  * hostapd / AP table
      3  * Copyright (c) 2002-2009, Jouni Malinen <j (at) 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 "drivers/driver.h"
     18 #include "hostapd.h"
     19 #include "ap_config.h"
     20 #include "ieee802_11.h"
     21 #include "sta_info.h"
     22 #include "beacon.h"
     23 #include "ap_list.h"
     24 
     25 
     26 /* AP list is a double linked list with head->prev pointing to the end of the
     27  * list and tail->next = NULL. Entries are moved to the head of the list
     28  * whenever a beacon has been received from the AP in question. The tail entry
     29  * in this link will thus be the least recently used entry. */
     30 
     31 
     32 static int ap_list_beacon_olbc(struct hostapd_iface *iface, struct ap_info *ap)
     33 {
     34 	int i;
     35 
     36 	if (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 		printf("AP: could not remove AP " MACSTR " from hash table\n",
    115 		       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 	struct os_time now;
    176 	int new_ap = 0;
    177 	int set_beacon = 0;
    178 
    179 	if (iface->conf->ap_table_max_size < 1)
    180 		return;
    181 
    182 	ap = ap_get_ap(iface, mgmt->bssid);
    183 	if (!ap) {
    184 		ap = ap_ap_add(iface, mgmt->bssid);
    185 		if (!ap) {
    186 			printf("Failed to allocate AP information entry\n");
    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 && elems->erp_info_len == 1)
    197 		ap->erp = elems->erp_info[0];
    198 	else
    199 		ap->erp = -1;
    200 
    201 	if (elems->ds_params && elems->ds_params_len == 1)
    202 		ap->channel = elems->ds_params[0];
    203 	else if (elems->ht_operation && elems->ht_operation_len >= 1)
    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_time(&now);
    214 	ap->last_beacon = now.sec;
    215 
    216 	if (!new_ap && ap != iface->ap_list) {
    217 		/* move AP entry into the beginning of the list so that the
    218 		 * oldest entry is always in the end of the list */
    219 		ap_ap_list_del(iface, ap);
    220 		ap_ap_list_add(iface, ap);
    221 	}
    222 
    223 	if (!iface->olbc &&
    224 	    ap_list_beacon_olbc(iface, ap)) {
    225 		iface->olbc = 1;
    226 		wpa_printf(MSG_DEBUG, "OLBC AP detected: " MACSTR
    227 			   " (channel %d) - enable protection",
    228 			   MAC2STR(ap->addr), ap->channel);
    229 		set_beacon++;
    230 	}
    231 
    232 #ifdef CONFIG_IEEE80211N
    233 	if (!iface->olbc_ht && !ap->ht_support &&
    234 	    (ap->channel == 0 ||
    235 	     ap->channel == iface->conf->channel ||
    236 	     ap->channel == iface->conf->channel +
    237 	     iface->conf->secondary_channel * 4)) {
    238 		iface->olbc_ht = 1;
    239 		hostapd_ht_operation_update(iface);
    240 		wpa_printf(MSG_DEBUG, "OLBC HT AP detected: " MACSTR
    241 			   " (channel %d) - enable protection",
    242 			   MAC2STR(ap->addr), ap->channel);
    243 		set_beacon++;
    244 	}
    245 #endif /* CONFIG_IEEE80211N */
    246 
    247 	if (set_beacon)
    248 		ieee802_11_update_beacons(iface);
    249 }
    250 
    251 
    252 static void ap_list_timer(void *eloop_ctx, void *timeout_ctx)
    253 {
    254 	struct hostapd_iface *iface = eloop_ctx;
    255 	struct os_time now;
    256 	struct ap_info *ap;
    257 	int set_beacon = 0;
    258 
    259 	eloop_register_timeout(10, 0, ap_list_timer, iface, NULL);
    260 
    261 	if (!iface->ap_list)
    262 		return;
    263 
    264 	os_get_time(&now);
    265 
    266 	while (iface->ap_list) {
    267 		ap = iface->ap_list->prev;
    268 		if (ap->last_beacon + iface->conf->ap_table_expiration_time >=
    269 		    now.sec)
    270 			break;
    271 
    272 		ap_free_ap(iface, ap);
    273 	}
    274 
    275 	if (iface->olbc || iface->olbc_ht) {
    276 		int olbc = 0;
    277 		int olbc_ht = 0;
    278 
    279 		ap = iface->ap_list;
    280 		while (ap && (olbc == 0 || olbc_ht == 0)) {
    281 			if (ap_list_beacon_olbc(iface, ap))
    282 				olbc = 1;
    283 			if (!ap->ht_support)
    284 				olbc_ht = 1;
    285 			ap = ap->next;
    286 		}
    287 		if (!olbc && iface->olbc) {
    288 			wpa_printf(MSG_DEBUG, "OLBC not detected anymore");
    289 			iface->olbc = 0;
    290 			set_beacon++;
    291 		}
    292 #ifdef CONFIG_IEEE80211N
    293 		if (!olbc_ht && iface->olbc_ht) {
    294 			wpa_printf(MSG_DEBUG, "OLBC HT not detected anymore");
    295 			iface->olbc_ht = 0;
    296 			hostapd_ht_operation_update(iface);
    297 			set_beacon++;
    298 		}
    299 #endif /* CONFIG_IEEE80211N */
    300 	}
    301 
    302 	if (set_beacon)
    303 		ieee802_11_update_beacons(iface);
    304 }
    305 
    306 
    307 int ap_list_init(struct hostapd_iface *iface)
    308 {
    309 	eloop_register_timeout(10, 0, ap_list_timer, iface, NULL);
    310 	return 0;
    311 }
    312 
    313 
    314 void ap_list_deinit(struct hostapd_iface *iface)
    315 {
    316 	eloop_cancel_timeout(ap_list_timer, iface, NULL);
    317 	hostapd_free_aps(iface);
    318 }
    319