hostap/hostapd/ap_list.c

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/*
* hostapd / AP table
* Copyright 2002-2003, Jouni Malinen <j@w1.fi>
* Copyright 2003-2004, Instant802 Networks, Inc.
* Copyright 2006, Devicescape Software, Inc.
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation.
*
* Alternatively, this software may be distributed under the terms of BSD
* license.
*
* See README and COPYING for more details.
*/
#include "includes.h"
#include "hostapd.h"
#include "ieee802_11.h"
#include "eloop.h"
#include "ap_list.h"
#include "hw_features.h"
#include "beacon.h"
struct ieee80211_frame_info {
u32 version;
u32 length;
u64 mactime;
u64 hosttime;
u32 phytype;
u32 channel;
u32 datarate;
u32 antenna;
u32 priority;
u32 ssi_type;
u32 ssi_signal;
u32 ssi_noise;
u32 preamble;
u32 encoding;
/* Note: this structure is otherwise identical to capture format used
* in linux-wlan-ng, but this additional field is used to provide meta
* data about the frame to hostapd. This was the easiest method for
* providing this information, but this might change in the future. */
u32 msg_type;
} __attribute__ ((packed));
enum ieee80211_phytype {
ieee80211_phytype_fhss_dot11_97 = 1,
ieee80211_phytype_dsss_dot11_97 = 2,
ieee80211_phytype_irbaseband = 3,
ieee80211_phytype_dsss_dot11_b = 4,
ieee80211_phytype_pbcc_dot11_b = 5,
ieee80211_phytype_ofdm_dot11_g = 6,
ieee80211_phytype_pbcc_dot11_g = 7,
ieee80211_phytype_ofdm_dot11_a = 8,
ieee80211_phytype_dsss_dot11_turbog = 255,
ieee80211_phytype_dsss_dot11_turbo = 256,
};
/* AP list is a double linked list with head->prev pointing to the end of the
* list and tail->next = NULL. Entries are moved to the head of the list
* whenever a beacon has been received from the AP in question. The tail entry
* in this link will thus be the least recently used entry. */
static void ap_list_new_ap(struct hostapd_iface *iface, struct ap_info *ap)
{
wpa_printf(MSG_DEBUG, "New AP detected: " MACSTR, MAC2STR(ap->addr));
/* TODO: could send a notification message to an external program that
* would then determine whether a rogue AP has been detected */
}
static void ap_list_expired_ap(struct hostapd_iface *iface, struct ap_info *ap)
{
wpa_printf(MSG_DEBUG, "AP info expired: " MACSTR, MAC2STR(ap->addr));
/* TODO: could send a notification message to an external program */
}
static int ap_list_beacon_olbc(struct hostapd_iface *iface, struct ap_info *ap)
{
int i;
if (iface->current_mode->mode != HOSTAPD_MODE_IEEE80211G ||
ap->phytype != ieee80211_phytype_pbcc_dot11_g ||
iface->conf->channel != ap->channel)
return 0;
if (ap->erp != -1 && (ap->erp & ERP_INFO_NON_ERP_PRESENT))
return 1;
for (i = 0; i < WLAN_SUPP_RATES_MAX; i++) {
int rate = (ap->supported_rates[i] & 0x7f) * 5;
if (rate == 60 || rate == 90 || rate > 110)
return 0;
}
return 1;
}
struct ap_info * ap_get_ap(struct hostapd_iface *iface, u8 *ap)
{
struct ap_info *s;
s = iface->ap_hash[STA_HASH(ap)];
while (s != NULL && os_memcmp(s->addr, ap, ETH_ALEN) != 0)
s = s->hnext;
return s;
}
static void ap_ap_list_add(struct hostapd_iface *iface, struct ap_info *ap)
{
if (iface->ap_list) {
ap->prev = iface->ap_list->prev;
iface->ap_list->prev = ap;
} else
ap->prev = ap;
ap->next = iface->ap_list;
iface->ap_list = ap;
}
static void ap_ap_list_del(struct hostapd_iface *iface, struct ap_info *ap)
{
if (iface->ap_list == ap)
iface->ap_list = ap->next;
else
ap->prev->next = ap->next;
if (ap->next)
ap->next->prev = ap->prev;
else if (iface->ap_list)
iface->ap_list->prev = ap->prev;
}
static void ap_ap_iter_list_add(struct hostapd_iface *iface,
struct ap_info *ap)
{
if (iface->ap_iter_list) {
ap->iter_prev = iface->ap_iter_list->iter_prev;
iface->ap_iter_list->iter_prev = ap;
} else
ap->iter_prev = ap;
ap->iter_next = iface->ap_iter_list;
iface->ap_iter_list = ap;
}
static void ap_ap_iter_list_del(struct hostapd_iface *iface,
struct ap_info *ap)
{
if (iface->ap_iter_list == ap)
iface->ap_iter_list = ap->iter_next;
else
ap->iter_prev->iter_next = ap->iter_next;
if (ap->iter_next)
ap->iter_next->iter_prev = ap->iter_prev;
else if (iface->ap_iter_list)
iface->ap_iter_list->iter_prev = ap->iter_prev;
}
static void ap_ap_hash_add(struct hostapd_iface *iface, struct ap_info *ap)
{
ap->hnext = iface->ap_hash[STA_HASH(ap->addr)];
iface->ap_hash[STA_HASH(ap->addr)] = ap;
}
static void ap_ap_hash_del(struct hostapd_iface *iface, struct ap_info *ap)
{
struct ap_info *s;
s = iface->ap_hash[STA_HASH(ap->addr)];
if (s == NULL) return;
if (os_memcmp(s->addr, ap->addr, ETH_ALEN) == 0) {
iface->ap_hash[STA_HASH(ap->addr)] = s->hnext;
return;
}
while (s->hnext != NULL &&
os_memcmp(s->hnext->addr, ap->addr, ETH_ALEN) != 0)
s = s->hnext;
if (s->hnext != NULL)
s->hnext = s->hnext->hnext;
else
printf("AP: could not remove AP " MACSTR " from hash table\n",
MAC2STR(ap->addr));
}
static void ap_free_ap(struct hostapd_iface *iface, struct ap_info *ap)
{
ap_ap_hash_del(iface, ap);
ap_ap_list_del(iface, ap);
ap_ap_iter_list_del(iface, ap);
iface->num_ap--;
os_free(ap);
}
static void hostapd_free_aps(struct hostapd_iface *iface)
{
struct ap_info *ap, *prev;
ap = iface->ap_list;
while (ap) {
prev = ap;
ap = ap->next;
ap_free_ap(iface, prev);
}
iface->ap_list = NULL;
}
int ap_ap_for_each(struct hostapd_iface *iface,
int (*func)(struct ap_info *s, void *data), void *data)
{
struct ap_info *s;
int ret = 0;
s = iface->ap_list;
while (s) {
ret = func(s, data);
if (ret)
break;
s = s->next;
}
return ret;
}
static struct ap_info * ap_ap_add(struct hostapd_iface *iface, u8 *addr)
{
struct ap_info *ap;
ap = os_zalloc(sizeof(struct ap_info));
if (ap == NULL)
return NULL;
/* initialize AP info data */
os_memcpy(ap->addr, addr, ETH_ALEN);
ap_ap_list_add(iface, ap);
iface->num_ap++;
ap_ap_hash_add(iface, ap);
ap_ap_iter_list_add(iface, ap);
if (iface->num_ap > iface->conf->ap_table_max_size && ap != ap->prev) {
wpa_printf(MSG_DEBUG, "Removing the least recently used AP "
MACSTR " from AP table", MAC2STR(ap->prev->addr));
if (iface->conf->passive_scan_interval > 0)
ap_list_expired_ap(iface, ap->prev);
ap_free_ap(iface, ap->prev);
}
return ap;
}
void ap_list_process_beacon(struct hostapd_iface *iface,
struct ieee80211_mgmt *mgmt,
struct ieee802_11_elems *elems,
struct hostapd_frame_info *fi)
{
struct ap_info *ap;
int new_ap = 0;
size_t len;
if (iface->conf->ap_table_max_size < 1)
return;
ap = ap_get_ap(iface, mgmt->bssid);
if (!ap) {
ap = ap_ap_add(iface, mgmt->bssid);
if (!ap) {
printf("Failed to allocate AP information entry\n");
return;
}
new_ap = 1;
}
ap->beacon_int = le_to_host16(mgmt->u.beacon.beacon_int);
ap->capability = le_to_host16(mgmt->u.beacon.capab_info);
if (elems->ssid) {
len = elems->ssid_len;
if (len >= sizeof(ap->ssid))
len = sizeof(ap->ssid) - 1;
os_memcpy(ap->ssid, elems->ssid, len);
ap->ssid[len] = '\0';
ap->ssid_len = len;
}
os_memset(ap->supported_rates, 0, WLAN_SUPP_RATES_MAX);
len = 0;
if (elems->supp_rates) {
len = elems->supp_rates_len;
if (len > WLAN_SUPP_RATES_MAX)
len = WLAN_SUPP_RATES_MAX;
os_memcpy(ap->supported_rates, elems->supp_rates, len);
}
if (elems->ext_supp_rates) {
int len2;
if (len + elems->ext_supp_rates_len > WLAN_SUPP_RATES_MAX)
len2 = WLAN_SUPP_RATES_MAX - len;
else
len2 = elems->ext_supp_rates_len;
os_memcpy(ap->supported_rates + len, elems->ext_supp_rates,
len2);
}
ap->wpa = elems->wpa_ie != NULL;
if (elems->erp_info && elems->erp_info_len == 1)
ap->erp = elems->erp_info[0];
else
ap->erp = -1;
if (elems->ds_params && elems->ds_params_len == 1)
ap->channel = elems->ds_params[0];
else if (fi)
ap->channel = fi->channel;
ap->num_beacons++;
time(&ap->last_beacon);
if (fi) {
ap->phytype = fi->phytype;
ap->ssi_signal = fi->ssi_signal;
ap->datarate = fi->datarate;
}
if (new_ap) {
if (iface->conf->passive_scan_interval > 0)
ap_list_new_ap(iface, ap);
} else if (ap != iface->ap_list) {
/* move AP entry into the beginning of the list so that the
* oldest entry is always in the end of the list */
ap_ap_list_del(iface, ap);
ap_ap_list_add(iface, ap);
}
if (!iface->olbc &&
ap_list_beacon_olbc(iface, ap)) {
struct hostapd_data *hapd = iface->bss[0];
iface->olbc = 1;
wpa_printf(MSG_DEBUG, "OLBC AP detected: " MACSTR " - enable "
"protection", MAC2STR(ap->addr));
ieee802_11_set_beacons(hapd->iface);
}
}
static void ap_list_timer(void *eloop_ctx, void *timeout_ctx)
{
struct hostapd_iface *iface = eloop_ctx;
time_t now;
struct ap_info *ap;
eloop_register_timeout(10, 0, ap_list_timer, iface, NULL);
if (!iface->ap_list)
return;
time(&now);
/* FIX: it looks like jkm-Purina ended up in busy loop in this
* function. Apparently, something can still cause a loop in the AP
* list.. */
while (iface->ap_list) {
ap = iface->ap_list->prev;
if (ap->last_beacon + iface->conf->ap_table_expiration_time >=
now)
break;
if (iface->conf->passive_scan_interval > 0)
ap_list_expired_ap(iface, ap);
ap_free_ap(iface, ap);
}
if (iface->olbc) {
int olbc = 0;
ap = iface->ap_list;
while (ap) {
if (ap_list_beacon_olbc(iface, ap)) {
olbc = 1;
break;
}
ap = ap->next;
}
if (!olbc) {
struct hostapd_data *hapd = iface->bss[0];
wpa_printf(MSG_DEBUG, "OLBC not detected anymore");
iface->olbc = 0;
ieee802_11_set_beacons(hapd->iface);
}
}
}
int ap_list_init(struct hostapd_iface *iface)
{
eloop_register_timeout(10, 0, ap_list_timer, iface, NULL);
return 0;
}
void ap_list_deinit(struct hostapd_iface *iface)
{
eloop_cancel_timeout(ap_list_timer, iface, NULL);
hostapd_free_aps(iface);
}
int ap_list_reconfig(struct hostapd_iface *iface,
struct hostapd_config *oldconf)
{
time_t now;
struct ap_info *ap;
if (iface->conf->ap_table_max_size == oldconf->ap_table_max_size &&
iface->conf->ap_table_expiration_time ==
oldconf->ap_table_expiration_time)
return 0;
time(&now);
while (iface->ap_list) {
ap = iface->ap_list->prev;
if (iface->num_ap <= iface->conf->ap_table_max_size &&
ap->last_beacon + iface->conf->ap_table_expiration_time >=
now)
break;
if (iface->conf->passive_scan_interval > 0)
ap_list_expired_ap(iface, iface->ap_list->prev);
ap_free_ap(iface, iface->ap_list->prev);
}
return 0;
}