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 "common/ieee802_11_defs.h"
  22 #include "common/ieee802_11_common.h"
  23 #include "drivers/driver.h"
  24 #include "hostapd.h"
  25 #include "ap_config.h"
  26 #include "ieee802_11.h"
  27 #include "sta_info.h"
  28 #include "beacon.h"
  29 #include "ap_list.h"
  30
  31
  32 /* AP list is a double linked list with head->prev pointing to the end of the
  33  * list and tail->next = NULL. Entries are moved to the head of the list
  34  * whenever a beacon has been received from the AP in question. The tail entry
  35  * in this link will thus be the least recently used entry. */
  36
  37
  38 static int ap_list_beacon_olbc(struct hostapd_iface *iface, struct ap_info *ap)
  39 {
  40         int i;
  41
  42         if (iface->current_mode->mode != HOSTAPD_MODE_IEEE80211G ||
  43             iface->conf->channel != ap->channel)
  44                 return 0;
  45
  46         if (ap->erp != -1 && (ap->erp & ERP_INFO_NON_ERP_PRESENT))
  47                 return 1;
  48
  49         for (i = 0; i < WLAN_SUPP_RATES_MAX; i++) {
  50                 int rate = (ap->supported_rates[i] & 0x7f) * 5;
  51                 if (rate == 60 || rate == 90 || rate > 110)
  52                         return 0;
  53         }
  54
  55         return 1;
  56 }
  57
  58
  59 struct ap_info * ap_get_ap(struct hostapd_iface *iface, const u8 *ap)
  60 {
  61         struct ap_info *s;
  62
  63         s = iface->ap_hash[STA_HASH(ap)];
  64         while (s != NULL && os_memcmp(s->addr, ap, ETH_ALEN) != 0)
  65                 s = s->hnext;
  66         return s;
  67 }
  68
  69
  70 static void ap_ap_list_add(struct hostapd_iface *iface, struct ap_info *ap)
  71 {
  72         if (iface->ap_list) {
  73                 ap->prev = iface->ap_list->prev;
  74                 iface->ap_list->prev = ap;
  75         } else
  76                 ap->prev = ap;
  77         ap->next = iface->ap_list;
  78         iface->ap_list = ap;
  79 }
  80
  81
  82 static void ap_ap_list_del(struct hostapd_iface *iface, struct ap_info *ap)
  83 {
  84         if (iface->ap_list == ap)
  85                 iface->ap_list = ap->next;
  86         else
  87                 ap->prev->next = ap->next;
  88
  89         if (ap->next)
  90                 ap->next->prev = ap->prev;
  91         else if (iface->ap_list)
  92                 iface->ap_list->prev = ap->prev;
  93 }
  94
  95
  96 static void ap_ap_iter_list_add(struct hostapd_iface *iface,
  97                                 struct ap_info *ap)
  98 {
  99         if (iface->ap_iter_list) {
 100                 ap->iter_prev = iface->ap_iter_list->iter_prev;
 101                 iface->ap_iter_list->iter_prev = ap;
 102         } else
 103                 ap->iter_prev = ap;
 104         ap->iter_next = iface->ap_iter_list;
 105         iface->ap_iter_list = ap;
 106 }
 107
 108
 109 static void ap_ap_iter_list_del(struct hostapd_iface *iface,
 110                                 struct ap_info *ap)
 111 {
 112         if (iface->ap_iter_list == ap)
 113                 iface->ap_iter_list = ap->iter_next;
 114         else
 115                 ap->iter_prev->iter_next = ap->iter_next;
 116
 117         if (ap->iter_next)
 118                 ap->iter_next->iter_prev = ap->iter_prev;
 119         else if (iface->ap_iter_list)
 120                 iface->ap_iter_list->iter_prev = ap->iter_prev;
 121 }
 122
 123
 124 static void ap_ap_hash_add(struct hostapd_iface *iface, struct ap_info *ap)
 125 {
 126         ap->hnext = iface->ap_hash[STA_HASH(ap->addr)];
 127         iface->ap_hash[STA_HASH(ap->addr)] = ap;
 128 }
 129
 130
 131 static void ap_ap_hash_del(struct hostapd_iface *iface, struct ap_info *ap)
 132 {
 133         struct ap_info *s;
 134
 135         s = iface->ap_hash[STA_HASH(ap->addr)];
 136         if (s == NULL) return;
 137         if (os_memcmp(s->addr, ap->addr, ETH_ALEN) == 0) {
 138                 iface->ap_hash[STA_HASH(ap->addr)] = s->hnext;
 139                 return;
 140         }
 141
 142         while (s->hnext != NULL &&
 143                os_memcmp(s->hnext->addr, ap->addr, ETH_ALEN) != 0)
 144                 s = s->hnext;
 145         if (s->hnext != NULL)
 146                 s->hnext = s->hnext->hnext;
 147         else
 148                 printf("AP: could not remove AP " MACSTR " from hash table\n",
 149                        MAC2STR(ap->addr));
 150 }
 151
 152
 153 static void ap_free_ap(struct hostapd_iface *iface, struct ap_info *ap)
 154 {
 155         ap_ap_hash_del(iface, ap);
 156         ap_ap_list_del(iface, ap);
 157         ap_ap_iter_list_del(iface, ap);
 158
 159         iface->num_ap--;
 160         os_free(ap);
 161 }
 162
 163
 164 static void hostapd_free_aps(struct hostapd_iface *iface)
 165 {
 166         struct ap_info *ap, *prev;
 167
 168         ap = iface->ap_list;
 169
 170         while (ap) {
 171                 prev = ap;
 172                 ap = ap->next;
 173                 ap_free_ap(iface, prev);
 174         }
 175
 176         iface->ap_list = NULL;
 177 }
 178
 179
 180 int ap_ap_for_each(struct hostapd_iface *iface,
 181                    int (*func)(struct ap_info *s, void *data), void *data)
 182 {
 183         struct ap_info *s;
 184         int ret = 0;
 185
 186         s = iface->ap_list;
 187
 188         while (s) {
 189                 ret = func(s, data);
 190                 if (ret)
 191                         break;
 192                 s = s->next;
 193         }
 194
 195         return ret;
 196 }
 197
 198
 199 static struct ap_info * ap_ap_add(struct hostapd_iface *iface, const u8 *addr)
 200 {
 201         struct ap_info *ap;
 202
 203         ap = os_zalloc(sizeof(struct ap_info));
 204         if (ap == NULL)
 205                 return NULL;
 206
 207         /* initialize AP info data */
 208         os_memcpy(ap->addr, addr, ETH_ALEN);
 209         ap_ap_list_add(iface, ap);
 210         iface->num_ap++;
 211         ap_ap_hash_add(iface, ap);
 212         ap_ap_iter_list_add(iface, ap);
 213
 214         if (iface->num_ap > iface->conf->ap_table_max_size && ap != ap->prev) {
 215                 wpa_printf(MSG_DEBUG, "Removing the least recently used AP "
 216                            MACSTR " from AP table", MAC2STR(ap->prev->addr));
 217                 ap_free_ap(iface, ap->prev);
 218         }
 219
 220         return ap;
 221 }
 222
 223
 224 void ap_list_process_beacon(struct hostapd_iface *iface,
 225                             const struct ieee80211_mgmt *mgmt,
 226                             struct ieee802_11_elems *elems,
 227                             struct hostapd_frame_info *fi)
 228 {
 229         struct ap_info *ap;
 230         int new_ap = 0;
 231         size_t len;
 232         int set_beacon = 0;
 233
 234         if (iface->conf->ap_table_max_size < 1)
 235                 return;
 236
 237         ap = ap_get_ap(iface, mgmt->bssid);
 238         if (!ap) {
 239                 ap = ap_ap_add(iface, mgmt->bssid);
 240                 if (!ap) {
 241                         printf("Failed to allocate AP information entry\n");
 242                         return;
 243                 }
 244                 new_ap = 1;
 245         }
 246
 247         ap->beacon_int = le_to_host16(mgmt->u.beacon.beacon_int);
 248         ap->capability = le_to_host16(mgmt->u.beacon.capab_info);
 249
 250         if (elems->ssid) {
 251                 len = elems->ssid_len;
 252                 if (len >= sizeof(ap->ssid))
 253                         len = sizeof(ap->ssid) - 1;
 254                 os_memcpy(ap->ssid, elems->ssid, len);
 255                 ap->ssid[len] = '\0';
 256                 ap->ssid_len = len;
 257         }
 258
 259         os_memset(ap->supported_rates, 0, WLAN_SUPP_RATES_MAX);
 260         len = 0;
 261         if (elems->supp_rates) {
 262                 len = elems->supp_rates_len;
 263                 if (len > WLAN_SUPP_RATES_MAX)
 264                         len = WLAN_SUPP_RATES_MAX;
 265                 os_memcpy(ap->supported_rates, elems->supp_rates, len);
 266         }
 267         if (elems->ext_supp_rates) {
 268                 int len2;
 269                 if (len + elems->ext_supp_rates_len > WLAN_SUPP_RATES_MAX)
 270                         len2 = WLAN_SUPP_RATES_MAX - len;
 271                 else
 272                         len2 = elems->ext_supp_rates_len;
 273                 os_memcpy(ap->supported_rates + len, elems->ext_supp_rates,
 274                           len2);
 275         }
 276
 277         ap->wpa = elems->wpa_ie != NULL;
 278
 279         if (elems->erp_info && elems->erp_info_len == 1)
 280                 ap->erp = elems->erp_info[0];
 281         else
 282                 ap->erp = -1;
 283
 284         if (elems->ds_params && elems->ds_params_len == 1)
 285                 ap->channel = elems->ds_params[0];
 286         else if (fi)
 287                 ap->channel = fi->channel;
 288
 289         if (elems->ht_capabilities)
 290                 ap->ht_support = 1;
 291         else
 292                 ap->ht_support = 0;
 293
 294         ap->num_beacons++;
 295         time(&ap->last_beacon);
 296         if (fi) {
 297                 ap->ssi_signal = fi->ssi_signal;
 298                 ap->datarate = fi->datarate;
 299         }
 300
 301         if (!new_ap && ap != iface->ap_list) {
 302                 /* move AP entry into the beginning of the list so that the
 303                  * oldest entry is always in the end of the list */
 304                 ap_ap_list_del(iface, ap);
 305                 ap_ap_list_add(iface, ap);
 306         }
 307
 308         if (!iface->olbc &&
 309             ap_list_beacon_olbc(iface, ap)) {
 310                 iface->olbc = 1;
 311                 wpa_printf(MSG_DEBUG, "OLBC AP detected: " MACSTR " - enable "
 312                            "protection", MAC2STR(ap->addr));
 313                 set_beacon++;
 314         }
 315
 316 #ifdef CONFIG_IEEE80211N
 317         if (!iface->olbc_ht && !ap->ht_support) {
 318                 iface->olbc_ht = 1;
 319                 hostapd_ht_operation_update(iface);
 320                 wpa_printf(MSG_DEBUG, "OLBC HT AP detected: " MACSTR
 321                            " - enable protection", MAC2STR(ap->addr));
 322                 set_beacon++;
 323         }
 324 #endif /* CONFIG_IEEE80211N */
 325
 326         if (set_beacon)
 327                 ieee802_11_set_beacons(iface);
 328 }
 329
 330
 331 static void ap_list_timer(void *eloop_ctx, void *timeout_ctx)
 332 {
 333         struct hostapd_iface *iface = eloop_ctx;
 334         time_t now;
 335         struct ap_info *ap;
 336         int set_beacon = 0;
 337
 338         eloop_register_timeout(10, 0, ap_list_timer, iface, NULL);
 339
 340         if (!iface->ap_list)
 341                 return;
 342
 343         time(&now);
 344
 345         while (iface->ap_list) {
 346                 ap = iface->ap_list->prev;
 347                 if (ap->last_beacon + iface->conf->ap_table_expiration_time >=
 348                     now)
 349                         break;
 350
 351                 ap_free_ap(iface, ap);
 352         }
 353
 354         if (iface->olbc || iface->olbc_ht) {
 355                 int olbc = 0;
 356                 int olbc_ht = 0;
 357
 358                 ap = iface->ap_list;
 359                 while (ap && (olbc == 0 || olbc_ht == 0)) {
 360                         if (ap_list_beacon_olbc(iface, ap))
 361                                 olbc = 1;
 362                         if (!ap->ht_support)
 363                                 olbc_ht = 1;
 364                         ap = ap->next;
 365                 }
 366                 if (!olbc && iface->olbc) {
 367                         wpa_printf(MSG_DEBUG, "OLBC not detected anymore");
 368                         iface->olbc = 0;
 369                         set_beacon++;
 370                 }
 371 #ifdef CONFIG_IEEE80211N
 372                 if (!olbc_ht && iface->olbc_ht) {
 373                         wpa_printf(MSG_DEBUG, "OLBC HT not detected anymore");
 374                         iface->olbc_ht = 0;
 375                         hostapd_ht_operation_update(iface);
 376                         set_beacon++;
 377                 }
 378 #endif /* CONFIG_IEEE80211N */
 379         }
 380
 381         if (set_beacon)
 382                 ieee802_11_set_beacons(iface);
 383 }
 384
 385
 386 int ap_list_init(struct hostapd_iface *iface)
 387 {
 388         eloop_register_timeout(10, 0, ap_list_timer, iface, NULL);
 389         return 0;
 390 }
 391
 392
 393 void ap_list_deinit(struct hostapd_iface *iface)
 394 {
 395         eloop_cancel_timeout(ap_list_timer, iface, NULL);
 396         hostapd_free_aps(iface);
 397 }