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 == NULL ||
  36             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                 wpa_printf(MSG_INFO, "AP: could not remove AP " MACSTR
 115                            " from hash table",  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         int new_ap = 0;
 176         int set_beacon = 0;
 177
 178         if (iface->conf->ap_table_max_size < 1)
 179                 return;
 180
 181         ap = ap_get_ap(iface, mgmt->bssid);
 182         if (!ap) {
 183                 ap = ap_ap_add(iface, mgmt->bssid);
 184                 if (!ap) {
 185                         wpa_printf(MSG_INFO,
 186                                    "Failed to allocate AP information entry");
 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)
 197                 ap->erp = elems->erp_info[0];
 198         else
 199                 ap->erp = -1;
 200
 201         if (elems->ds_params)
 202                 ap->channel = elems->ds_params[0];
 203         else if (elems->ht_operation)
 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_reltime(&ap->last_beacon);
 214
 215         if (!new_ap && ap != iface->ap_list) {
 216                 /* move AP entry into the beginning of the list so that the
 217                  * oldest entry is always in the end of the list */
 218                 ap_ap_list_del(iface, ap);
 219                 ap_ap_list_add(iface, ap);
 220         }
 221
 222         if (!iface->olbc &&
 223             ap_list_beacon_olbc(iface, ap)) {
 224                 iface->olbc = 1;
 225                 wpa_printf(MSG_DEBUG, "OLBC AP detected: " MACSTR
 226                            " (channel %d) - enable protection",
 227                            MAC2STR(ap->addr), ap->channel);
 228                 set_beacon++;
 229         }
 230
 231 #ifdef CONFIG_IEEE80211N
 232         if (!iface->olbc_ht && !ap->ht_support &&
 233             (ap->channel == 0 ||
 234              ap->channel == iface->conf->channel ||
 235              ap->channel == iface->conf->channel +
 236              iface->conf->secondary_channel * 4)) {
 237                 iface->olbc_ht = 1;
 238                 hostapd_ht_operation_update(iface);
 239                 wpa_printf(MSG_DEBUG, "OLBC HT AP detected: " MACSTR
 240                            " (channel %d) - enable protection",
 241                            MAC2STR(ap->addr), ap->channel);
 242                 set_beacon++;
 243         }
 244 #endif /* CONFIG_IEEE80211N */
 245
 246         if (set_beacon)
 247                 ieee802_11_update_beacons(iface);
 248 }
 249
 250
 251 void ap_list_timer(struct hostapd_iface *iface)
 252 {
 253         struct os_reltime now;
 254         struct ap_info *ap;
 255         int set_beacon = 0;
 256
 257         if (!iface->ap_list)
 258                 return;
 259
 260         os_get_reltime(&now);
 261
 262         while (iface->ap_list) {
 263                 ap = iface->ap_list->prev;
 264                 if (!os_reltime_expired(&now, &ap->last_beacon,
 265                                         iface->conf->ap_table_expiration_time))
 266                         break;
 267
 268                 ap_free_ap(iface, ap);
 269         }
 270
 271         if (iface->olbc || iface->olbc_ht) {
 272                 int olbc = 0;
 273                 int olbc_ht = 0;
 274
 275                 ap = iface->ap_list;
 276                 while (ap && (olbc == 0 || olbc_ht == 0)) {
 277                         if (ap_list_beacon_olbc(iface, ap))
 278                                 olbc = 1;
 279                         if (!ap->ht_support)
 280                                 olbc_ht = 1;
 281                         ap = ap->next;
 282                 }
 283                 if (!olbc && iface->olbc) {
 284                         wpa_printf(MSG_DEBUG, "OLBC not detected anymore");
 285                         iface->olbc = 0;
 286                         set_beacon++;
 287                 }
 288 #ifdef CONFIG_IEEE80211N
 289                 if (!olbc_ht && iface->olbc_ht) {
 290                         wpa_printf(MSG_DEBUG, "OLBC HT not detected anymore");
 291                         iface->olbc_ht = 0;
 292                         hostapd_ht_operation_update(iface);
 293                         set_beacon++;
 294                 }
 295 #endif /* CONFIG_IEEE80211N */
 296         }
 297
 298         if (set_beacon)
 299                 ieee802_11_update_beacons(iface);
 300 }
 301
 302
 303 int ap_list_init(struct hostapd_iface *iface)
 304 {
 305         return 0;
 306 }
 307
 308
 309 void ap_list_deinit(struct hostapd_iface *iface)
 310 {
 311         hostapd_free_aps(iface);
 312 }