contrib/hostapd/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 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
  31 static int ap_list_beacon_olbc(struct hostapd_iface *iface, struct ap_info *ap)
  32 {
  33         int i;
  34
  35         if (iface->current_mode->mode != HOSTAPD_MODE_IEEE80211G ||
  36             iface->conf->channel != ap->channel)
  37                 return 0;
  38
  39         if (ap->erp != -1 && (ap->erp & ERP_INFO_NON_ERP_PRESENT))
  40                 return 1;
  41
  42         for (i = 0; i < WLAN_SUPP_RATES_MAX; i++) {
  43                 int rate = (ap->supported_rates[i] & 0x7f) * 5;
  44                 if (rate == 60 || rate == 90 || rate > 110)
  45                         return 0;
  46         }
  47
  48         return 1;
  49 }
  50
  51
  52 static struct ap_info * ap_get_ap(struct hostapd_iface *iface, const u8 *ap)
  53 {
  54         struct ap_info *s;
  55
  56         s = iface->ap_hash[STA_HASH(ap)];
  57         while (s != NULL && os_memcmp(s->addr, ap, ETH_ALEN) != 0)
  58                 s = s->hnext;
  59         return s;
  60 }
  61
  62
  63 static void ap_ap_list_add(struct hostapd_iface *iface, struct ap_info *ap)
  64 {
  65         if (iface->ap_list) {
  66                 ap->prev = iface->ap_list->prev;
  67                 iface->ap_list->prev = ap;
  68         } else
  69                 ap->prev = ap;
  70         ap->next = iface->ap_list;
  71         iface->ap_list = ap;
  72 }
  73
  74
  75 static void ap_ap_list_del(struct hostapd_iface *iface, struct ap_info *ap)
  76 {
  77         if (iface->ap_list == ap)
  78                 iface->ap_list = ap->next;
  79         else
  80                 ap->prev->next = ap->next;
  81
  82         if (ap->next)
  83                 ap->next->prev = ap->prev;
  84         else if (iface->ap_list)
  85                 iface->ap_list->prev = ap->prev;
  86 }
  87
  88
  89 static void ap_ap_hash_add(struct hostapd_iface *iface, struct ap_info *ap)
  90 {
  91         ap->hnext = iface->ap_hash[STA_HASH(ap->addr)];
  92         iface->ap_hash[STA_HASH(ap->addr)] = ap;
  93 }
  94
  95
  96 static void ap_ap_hash_del(struct hostapd_iface *iface, struct ap_info *ap)
  97 {
  98         struct ap_info *s;
  99
 100         s = iface->ap_hash[STA_HASH(ap->addr)];
 101         if (s == NULL) return;
 102         if (os_memcmp(s->addr, ap->addr, ETH_ALEN) == 0) {
 103                 iface->ap_hash[STA_HASH(ap->addr)] = s->hnext;
 104                 return;
 105         }
 106
 107         while (s->hnext != NULL &&
 108                os_memcmp(s->hnext->addr, ap->addr, ETH_ALEN) != 0)
 109                 s = s->hnext;
 110         if (s->hnext != NULL)
 111                 s->hnext = s->hnext->hnext;
 112         else
 113                 printf("AP: could not remove AP " MACSTR " from hash table\n",
 114                        MAC2STR(ap->addr));
 115 }
 116
 117
 118 static void ap_free_ap(struct hostapd_iface *iface, struct ap_info *ap)
 119 {
 120         ap_ap_hash_del(iface, ap);
 121         ap_ap_list_del(iface, ap);
 122
 123         iface->num_ap--;
 124         os_free(ap);
 125 }
 126
 127
 128 static void hostapd_free_aps(struct hostapd_iface *iface)
 129 {
 130         struct ap_info *ap, *prev;
 131
 132         ap = iface->ap_list;
 133
 134         while (ap) {
 135                 prev = ap;
 136                 ap = ap->next;
 137                 ap_free_ap(iface, prev);
 138         }
 139
 140         iface->ap_list = NULL;
 141 }
 142
 143
 144 static struct ap_info * ap_ap_add(struct hostapd_iface *iface, const u8 *addr)
 145 {
 146         struct ap_info *ap;
 147
 148         ap = os_zalloc(sizeof(struct ap_info));
 149         if (ap == NULL)
 150                 return NULL;
 151
 152         /* initialize AP info data */
 153         os_memcpy(ap->addr, addr, ETH_ALEN);
 154         ap_ap_list_add(iface, ap);
 155         iface->num_ap++;
 156         ap_ap_hash_add(iface, ap);
 157
 158         if (iface->num_ap > iface->conf->ap_table_max_size && ap != ap->prev) {
 159                 wpa_printf(MSG_DEBUG, "Removing the least recently used AP "
 160                            MACSTR " from AP table", MAC2STR(ap->prev->addr));
 161                 ap_free_ap(iface, ap->prev);
 162         }
 163
 164         return ap;
 165 }
 166
 167
 168 void ap_list_process_beacon(struct hostapd_iface *iface,
 169                             const struct ieee80211_mgmt *mgmt,
 170                             struct ieee802_11_elems *elems,
 171                             struct hostapd_frame_info *fi)
 172 {
 173         struct ap_info *ap;
 174         int new_ap = 0;
 175         int set_beacon = 0;
 176
 177         if (iface->conf->ap_table_max_size < 1)
 178                 return;
 179
 180         ap = ap_get_ap(iface, mgmt->bssid);
 181         if (!ap) {
 182                 ap = ap_ap_add(iface, mgmt->bssid);
 183                 if (!ap) {
 184                         printf("Failed to allocate AP information entry\n");
 185                         return;
 186                 }
 187                 new_ap = 1;
 188         }
 189
 190         merge_byte_arrays(ap->supported_rates, WLAN_SUPP_RATES_MAX,
 191                           elems->supp_rates, elems->supp_rates_len,
 192                           elems->ext_supp_rates, elems->ext_supp_rates_len);
 193
 194         if (elems->erp_info && elems->erp_info_len == 1)
 195                 ap->erp = elems->erp_info[0];
 196         else
 197                 ap->erp = -1;
 198
 199         if (elems->ds_params && elems->ds_params_len == 1)
 200                 ap->channel = elems->ds_params[0];
 201         else if (elems->ht_operation && elems->ht_operation_len >= 1)
 202                 ap->channel = elems->ht_operation[0];
 203         else if (fi)
 204                 ap->channel = fi->channel;
 205
 206         if (elems->ht_capabilities)
 207                 ap->ht_support = 1;
 208         else
 209                 ap->ht_support = 0;
 210
 211         os_get_reltime(&ap->last_beacon);
 212
 213         if (!new_ap && ap != iface->ap_list) {
 214                 /* move AP entry into the beginning of the list so that the
 215                  * oldest entry is always in the end of the list */
 216                 ap_ap_list_del(iface, ap);
 217                 ap_ap_list_add(iface, ap);
 218         }
 219
 220         if (!iface->olbc &&
 221             ap_list_beacon_olbc(iface, ap)) {
 222                 iface->olbc = 1;
 223                 wpa_printf(MSG_DEBUG, "OLBC AP detected: " MACSTR
 224                            " (channel %d) - enable protection",
 225                            MAC2STR(ap->addr), ap->channel);
 226                 set_beacon++;
 227         }
 228
 229 #ifdef CONFIG_IEEE80211N
 230         if (!iface->olbc_ht && !ap->ht_support &&
 231             (ap->channel == 0 ||
 232              ap->channel == iface->conf->channel ||
 233              ap->channel == iface->conf->channel +
 234              iface->conf->secondary_channel * 4)) {
 235                 iface->olbc_ht = 1;
 236                 hostapd_ht_operation_update(iface);
 237                 wpa_printf(MSG_DEBUG, "OLBC HT AP detected: " MACSTR
 238                            " (channel %d) - enable protection",
 239                            MAC2STR(ap->addr), ap->channel);
 240                 set_beacon++;
 241         }
 242 #endif /* CONFIG_IEEE80211N */
 243
 244         if (set_beacon)
 245                 ieee802_11_update_beacons(iface);
 246 }
 247
 248
 249 static void ap_list_timer(void *eloop_ctx, void *timeout_ctx)
 250 {
 251         struct hostapd_iface *iface = eloop_ctx;
 252         struct os_reltime now;
 253         struct ap_info *ap;
 254         int set_beacon = 0;
 255
 256         eloop_register_timeout(10, 0, ap_list_timer, iface, NULL);
 257
 258         if (!iface->ap_list)
 259                 return;
 260
 261         os_get_reltime(&now);
 262
 263         while (iface->ap_list) {
 264                 ap = iface->ap_list->prev;
 265                 if (!os_reltime_expired(&now, &ap->last_beacon,
 266                                         iface->conf->ap_table_expiration_time))
 267                         break;
 268
 269                 ap_free_ap(iface, ap);
 270         }
 271
 272         if (iface->olbc || iface->olbc_ht) {
 273                 int olbc = 0;
 274                 int olbc_ht = 0;
 275
 276                 ap = iface->ap_list;
 277                 while (ap && (olbc == 0 || olbc_ht == 0)) {
 278                         if (ap_list_beacon_olbc(iface, ap))
 279                                 olbc = 1;
 280                         if (!ap->ht_support)
 281                                 olbc_ht = 1;
 282                         ap = ap->next;
 283                 }
 284                 if (!olbc && iface->olbc) {
 285                         wpa_printf(MSG_DEBUG, "OLBC not detected anymore");
 286                         iface->olbc = 0;
 287                         set_beacon++;
 288                 }
 289 #ifdef CONFIG_IEEE80211N
 290                 if (!olbc_ht && iface->olbc_ht) {
 291                         wpa_printf(MSG_DEBUG, "OLBC HT not detected anymore");
 292                         iface->olbc_ht = 0;
 293                         hostapd_ht_operation_update(iface);
 294                         set_beacon++;
 295                 }
 296 #endif /* CONFIG_IEEE80211N */
 297         }
 298
 299         if (set_beacon)
 300                 ieee802_11_update_beacons(iface);
 301 }
 302
 303
 304 int ap_list_init(struct hostapd_iface *iface)
 305 {
 306         eloop_register_timeout(10, 0, ap_list_timer, iface, NULL);
 307         return 0;
 308 }
 309
 310
 311 void ap_list_deinit(struct hostapd_iface *iface)
 312 {
 313         eloop_cancel_timeout(ap_list_timer, iface, NULL);
 314         hostapd_free_aps(iface);
 315 }