src/ap/ap_list.c

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