hostapd/ap_list.c

   1 /*
   2  * hostapd / AP table
   3  * Copyright (c) 2002-2003, Jouni Malinen <j@w1.fi>
   4  * Copyright (c) 2003-2004, Instant802 Networks, Inc.
   5  * Copyright (c) 2006, Devicescape Software, Inc.
   6  *
   7  * This program is free software; you can redistribute it and/or modify
   8  * it under the terms of the GNU General Public License version 2 as
   9  * published by the Free Software Foundation.
  10  *
  11  * Alternatively, this software may be distributed under the terms of BSD
  12  * license.
  13  *
  14  * See README and COPYING for more details.
  15  */
  16
  17 #include "includes.h"
  18
  19 #include "common.h"
  20 #include "hostapd.h"
  21 #include "config.h"
  22 #include "ieee802_11.h"
  23 #include "eloop.h"
  24 #include "sta_info.h"
  25 #include "ap_list.h"
  26 #include "hw_features.h"
  27 #include "beacon.h"
  28 #include "drivers/driver.h"
  29
  30
  31 /* AP list is a double linked list with head->prev pointing to the end of the
  32  * list and tail->next = NULL. Entries are moved to the head of the list
  33  * whenever a beacon has been received from the AP in question. The tail entry
  34  * in this link will thus be the least recently used entry. */
  35
  36
  37 static int ap_list_beacon_olbc(struct hostapd_iface *iface, struct ap_info *ap)
  38 {
  39         int i;
  40
  41         if (iface->current_mode->mode != HOSTAPD_MODE_IEEE80211G ||
  42             iface->conf->channel != ap->channel)
  43                 return 0;
  44
  45         if (ap->erp != -1 && (ap->erp & ERP_INFO_NON_ERP_PRESENT))
  46                 return 1;
  47
  48         for (i = 0; i < WLAN_SUPP_RATES_MAX; i++) {
  49                 int rate = (ap->supported_rates[i] & 0x7f) * 5;
  50                 if (rate == 60 || rate == 90 || rate > 110)
  51                         return 0;
  52         }
  53
  54         return 1;
  55 }
  56
  57
  58 struct ap_info * ap_get_ap(struct hostapd_iface *iface, const u8 *ap)
  59 {
  60         struct ap_info *s;
  61
  62         s = iface->ap_hash[STA_HASH(ap)];
  63         while (s != NULL && os_memcmp(s->addr, ap, ETH_ALEN) != 0)
  64                 s = s->hnext;
  65         return s;
  66 }
  67
  68
  69 static void ap_ap_list_add(struct hostapd_iface *iface, struct ap_info *ap)
  70 {
  71         if (iface->ap_list) {
  72                 ap->prev = iface->ap_list->prev;
  73                 iface->ap_list->prev = ap;
  74         } else
  75                 ap->prev = ap;
  76         ap->next = iface->ap_list;
  77         iface->ap_list = ap;
  78 }
  79
  80
  81 static void ap_ap_list_del(struct hostapd_iface *iface, struct ap_info *ap)
  82 {
  83         if (iface->ap_list == ap)
  84                 iface->ap_list = ap->next;
  85         else
  86                 ap->prev->next = ap->next;
  87
  88         if (ap->next)
  89                 ap->next->prev = ap->prev;
  90         else if (iface->ap_list)
  91                 iface->ap_list->prev = ap->prev;
  92 }
  93
  94
  95 static void ap_ap_iter_list_add(struct hostapd_iface *iface,
  96                                 struct ap_info *ap)
  97 {
  98         if (iface->ap_iter_list) {
  99                 ap->iter_prev = iface->ap_iter_list->iter_prev;
 100                 iface->ap_iter_list->iter_prev = ap;
 101         } else
 102                 ap->iter_prev = ap;
 103         ap->iter_next = iface->ap_iter_list;
 104         iface->ap_iter_list = ap;
 105 }
 106
 107
 108 static void ap_ap_iter_list_del(struct hostapd_iface *iface,
 109                                 struct ap_info *ap)
 110 {
 111         if (iface->ap_iter_list == ap)
 112                 iface->ap_iter_list = ap->iter_next;
 113         else
 114                 ap->iter_prev->iter_next = ap->iter_next;
 115
 116         if (ap->iter_next)
 117                 ap->iter_next->iter_prev = ap->iter_prev;
 118         else if (iface->ap_iter_list)
 119                 iface->ap_iter_list->iter_prev = ap->iter_prev;
 120 }
 121
 122
 123 static void ap_ap_hash_add(struct hostapd_iface *iface, struct ap_info *ap)
 124 {
 125         ap->hnext = iface->ap_hash[STA_HASH(ap->addr)];
 126         iface->ap_hash[STA_HASH(ap->addr)] = ap;
 127 }
 128
 129
 130 static void ap_ap_hash_del(struct hostapd_iface *iface, struct ap_info *ap)
 131 {
 132         struct ap_info *s;
 133
 134         s = iface->ap_hash[STA_HASH(ap->addr)];
 135         if (s == NULL) return;
 136         if (os_memcmp(s->addr, ap->addr, ETH_ALEN) == 0) {
 137                 iface->ap_hash[STA_HASH(ap->addr)] = s->hnext;
 138                 return;
 139         }
 140
 141         while (s->hnext != NULL &&
 142                os_memcmp(s->hnext->addr, ap->addr, ETH_ALEN) != 0)
 143                 s = s->hnext;
 144         if (s->hnext != NULL)
 145                 s->hnext = s->hnext->hnext;
 146         else
 147                 printf("AP: could not remove AP " MACSTR " from hash table\n",
 148                        MAC2STR(ap->addr));
 149 }
 150
 151
 152 static void ap_free_ap(struct hostapd_iface *iface, struct ap_info *ap)
 153 {
 154         ap_ap_hash_del(iface, ap);
 155         ap_ap_list_del(iface, ap);
 156         ap_ap_iter_list_del(iface, ap);
 157
 158         iface->num_ap--;
 159         os_free(ap);
 160 }
 161
 162
 163 static void hostapd_free_aps(struct hostapd_iface *iface)
 164 {
 165         struct ap_info *ap, *prev;
 166
 167         ap = iface->ap_list;
 168
 169         while (ap) {
 170                 prev = ap;
 171                 ap = ap->next;
 172                 ap_free_ap(iface, prev);
 173         }
 174
 175         iface->ap_list = NULL;
 176 }
 177
 178
 179 int ap_ap_for_each(struct hostapd_iface *iface,
 180                    int (*func)(struct ap_info *s, void *data), void *data)
 181 {
 182         struct ap_info *s;
 183         int ret = 0;
 184
 185         s = iface->ap_list;
 186
 187         while (s) {
 188                 ret = func(s, data);
 189                 if (ret)
 190                         break;
 191                 s = s->next;
 192         }
 193
 194         return ret;
 195 }
 196
 197
 198 static struct ap_info * ap_ap_add(struct hostapd_iface *iface, const u8 *addr)
 199 {
 200         struct ap_info *ap;
 201
 202         ap = os_zalloc(sizeof(struct ap_info));
 203         if (ap == NULL)
 204                 return NULL;
 205
 206         /* initialize AP info data */
 207         os_memcpy(ap->addr, addr, ETH_ALEN);
 208         ap_ap_list_add(iface, ap);
 209         iface->num_ap++;
 210         ap_ap_hash_add(iface, ap);
 211         ap_ap_iter_list_add(iface, ap);
 212
 213         if (iface->num_ap > iface->conf->ap_table_max_size && ap != ap->prev) {
 214                 wpa_printf(MSG_DEBUG, "Removing the least recently used AP "
 215                            MACSTR " from AP table", MAC2STR(ap->prev->addr));
 216                 ap_free_ap(iface, ap->prev);
 217         }
 218
 219         return ap;
 220 }
 221
 222
 223 void ap_list_process_beacon(struct hostapd_iface *iface,
 224                             const struct ieee80211_mgmt *mgmt,
 225                             struct ieee802_11_elems *elems,
 226                             struct hostapd_frame_info *fi)
 227 {
 228         struct ap_info *ap;
 229         int new_ap = 0;
 230         size_t len;
 231         int set_beacon = 0;
 232
 233         if (iface->conf->ap_table_max_size < 1)
 234                 return;
 235
 236         ap = ap_get_ap(iface, mgmt->bssid);
 237         if (!ap) {
 238                 ap = ap_ap_add(iface, mgmt->bssid);
 239                 if (!ap) {
 240                         printf("Failed to allocate AP information entry\n");
 241                         return;
 242                 }
 243                 new_ap = 1;
 244         }
 245
 246         ap->beacon_int = le_to_host16(mgmt->u.beacon.beacon_int);
 247         ap->capability = le_to_host16(mgmt->u.beacon.capab_info);
 248
 249         if (elems->ssid) {
 250                 len = elems->ssid_len;
 251                 if (len >= sizeof(ap->ssid))
 252                         len = sizeof(ap->ssid) - 1;
 253                 os_memcpy(ap->ssid, elems->ssid, len);
 254                 ap->ssid[len] = '\0';
 255                 ap->ssid_len = len;
 256         }
 257
 258         os_memset(ap->supported_rates, 0, WLAN_SUPP_RATES_MAX);
 259         len = 0;
 260         if (elems->supp_rates) {
 261                 len = elems->supp_rates_len;
 262                 if (len > WLAN_SUPP_RATES_MAX)
 263                         len = WLAN_SUPP_RATES_MAX;
 264                 os_memcpy(ap->supported_rates, elems->supp_rates, len);
 265         }
 266         if (elems->ext_supp_rates) {
 267                 int len2;
 268                 if (len + elems->ext_supp_rates_len > WLAN_SUPP_RATES_MAX)
 269                         len2 = WLAN_SUPP_RATES_MAX - len;
 270                 else
 271                         len2 = elems->ext_supp_rates_len;
 272                 os_memcpy(ap->supported_rates + len, elems->ext_supp_rates,
 273                           len2);
 274         }
 275
 276         ap->wpa = elems->wpa_ie != NULL;
 277
 278         if (elems->erp_info && elems->erp_info_len == 1)
 279                 ap->erp = elems->erp_info[0];
 280         else
 281                 ap->erp = -1;
 282
 283         if (elems->ds_params && elems->ds_params_len == 1)
 284                 ap->channel = elems->ds_params[0];
 285         else if (fi)
 286                 ap->channel = fi->channel;
 287
 288         if (elems->ht_capabilities)
 289                 ap->ht_support = 1;
 290         else
 291                 ap->ht_support = 0;
 292
 293         ap->num_beacons++;
 294         time(&ap->last_beacon);
 295         if (fi) {
 296                 ap->ssi_signal = fi->ssi_signal;
 297                 ap->datarate = fi->datarate;
 298         }
 299
 300         if (!new_ap && ap != iface->ap_list) {
 301                 /* move AP entry into the beginning of the list so that the
 302                  * oldest entry is always in the end of the list */
 303                 ap_ap_list_del(iface, ap);
 304                 ap_ap_list_add(iface, ap);
 305         }
 306
 307         if (!iface->olbc &&
 308             ap_list_beacon_olbc(iface, ap)) {
 309                 iface->olbc = 1;
 310                 wpa_printf(MSG_DEBUG, "OLBC AP detected: " MACSTR " - enable "
 311                            "protection", MAC2STR(ap->addr));
 312                 set_beacon++;
 313         }
 314
 315 #ifdef CONFIG_IEEE80211N
 316         if (!iface->olbc_ht && !ap->ht_support) {
 317                 iface->olbc_ht = 1;
 318                 hostapd_ht_operation_update(iface);
 319                 wpa_printf(MSG_DEBUG, "OLBC HT AP detected: " MACSTR
 320                            " - enable protection", MAC2STR(ap->addr));
 321                 set_beacon++;
 322         }
 323 #endif /* CONFIG_IEEE80211N */
 324
 325         if (set_beacon)
 326                 ieee802_11_set_beacons(iface);
 327 }
 328
 329
 330 static void ap_list_timer(void *eloop_ctx, void *timeout_ctx)
 331 {
 332         struct hostapd_iface *iface = eloop_ctx;
 333         time_t now;
 334         struct ap_info *ap;
 335         int set_beacon = 0;
 336
 337         eloop_register_timeout(10, 0, ap_list_timer, iface, NULL);
 338
 339         if (!iface->ap_list)
 340                 return;
 341
 342         time(&now);
 343
 344         while (iface->ap_list) {
 345                 ap = iface->ap_list->prev;
 346                 if (ap->last_beacon + iface->conf->ap_table_expiration_time >=
 347                     now)
 348                         break;
 349
 350                 ap_free_ap(iface, ap);
 351         }
 352
 353         if (iface->olbc || iface->olbc_ht) {
 354                 int olbc = 0;
 355                 int olbc_ht = 0;
 356
 357                 ap = iface->ap_list;
 358                 while (ap && (olbc == 0 || olbc_ht == 0)) {
 359                         if (ap_list_beacon_olbc(iface, ap))
 360                                 olbc = 1;
 361                         if (!ap->ht_support)
 362                                 olbc_ht = 1;
 363                         ap = ap->next;
 364                 }
 365                 if (!olbc && iface->olbc) {
 366                         wpa_printf(MSG_DEBUG, "OLBC not detected anymore");
 367                         iface->olbc = 0;
 368                         set_beacon++;
 369                 }
 370 #ifdef CONFIG_IEEE80211N
 371                 if (!olbc_ht && iface->olbc_ht) {
 372                         wpa_printf(MSG_DEBUG, "OLBC HT not detected anymore");
 373                         iface->olbc_ht = 0;
 374                         hostapd_ht_operation_update(iface);
 375                         set_beacon++;
 376                 }
 377 #endif /* CONFIG_IEEE80211N */
 378         }
 379
 380         if (set_beacon)
 381                 ieee802_11_set_beacons(iface);
 382 }
 383
 384
 385 int ap_list_init(struct hostapd_iface *iface)
 386 {
 387         eloop_register_timeout(10, 0, ap_list_timer, iface, NULL);
 388         return 0;
 389 }
 390
 391
 392 void ap_list_deinit(struct hostapd_iface *iface)
 393 {
 394         eloop_cancel_timeout(ap_list_timer, iface, NULL);
 395         hostapd_free_aps(iface);
 396 }