hostap/hostapd/beacon.c

419 lines
11 KiB
C
Raw Normal View History

/*
* hostapd / IEEE 802.11 Management: Beacon and Probe Request/Response
* Copyright (c) 2002-2004, Instant802 Networks, Inc.
* Copyright (c) 2005-2006, Devicescape Software, Inc.
* Copyright (c) 2008, Jouni Malinen <j@w1.fi>
*
* 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"
#ifndef CONFIG_NATIVE_WINDOWS
#include "hostapd.h"
#include "ieee802_11.h"
#include "wpa.h"
#include "wme.h"
#include "beacon.h"
#include "hw_features.h"
#include "driver.h"
#include "sta_info.h"
#include "ieee802_11h.h"
static u8 ieee802_11_erp_info(struct hostapd_data *hapd)
{
u8 erp = 0;
if (hapd->iface->current_mode == NULL ||
hapd->iface->current_mode->mode != HOSTAPD_MODE_IEEE80211G)
return 0;
switch (hapd->iconf->cts_protection_type) {
case CTS_PROTECTION_FORCE_ENABLED:
erp |= ERP_INFO_NON_ERP_PRESENT | ERP_INFO_USE_PROTECTION;
break;
case CTS_PROTECTION_FORCE_DISABLED:
erp = 0;
break;
case CTS_PROTECTION_AUTOMATIC:
if (hapd->iface->olbc)
erp |= ERP_INFO_USE_PROTECTION;
/* continue */
case CTS_PROTECTION_AUTOMATIC_NO_OLBC:
if (hapd->iface->num_sta_non_erp > 0) {
erp |= ERP_INFO_NON_ERP_PRESENT |
ERP_INFO_USE_PROTECTION;
}
break;
}
if (hapd->iface->num_sta_no_short_preamble > 0)
erp |= ERP_INFO_BARKER_PREAMBLE_MODE;
return erp;
}
static u8 * hostapd_eid_ds_params(struct hostapd_data *hapd, u8 *eid)
{
*eid++ = WLAN_EID_DS_PARAMS;
*eid++ = 1;
*eid++ = hapd->iconf->channel;
return eid;
}
static u8 * hostapd_eid_erp_info(struct hostapd_data *hapd, u8 *eid)
{
if (hapd->iface->current_mode == NULL ||
hapd->iface->current_mode->mode != HOSTAPD_MODE_IEEE80211G)
return eid;
/* Set NonERP_present and use_protection bits if there
* are any associated NonERP stations. */
/* TODO: use_protection bit can be set to zero even if
* there are NonERP stations present. This optimization
* might be useful if NonERP stations are "quiet".
* See 802.11g/D6 E-1 for recommended practice.
* In addition, Non ERP present might be set, if AP detects Non ERP
* operation on other APs. */
/* Add ERP Information element */
*eid++ = WLAN_EID_ERP_INFO;
*eid++ = 1;
*eid++ = ieee802_11_erp_info(hapd);
return eid;
}
static u8 * hostapd_eid_country(struct hostapd_data *hapd, u8 *eid,
int max_len)
{
u8 *pos = eid;
if ((!hapd->iconf->ieee80211d && !hapd->iface->dfs_enable) ||
max_len < 6)
return eid;
*pos++ = WLAN_EID_COUNTRY;
pos++; /* length will be set later */
os_memcpy(pos, hapd->iconf->country, 3); /* e.g., 'US ' */
pos += 3;
if ((pos - eid) & 1)
*pos++ = 0; /* pad for 16-bit alignment */
eid[1] = (pos - eid) - 2;
return pos;
}
static u8 * hostapd_eid_power_constraint(struct hostapd_data *hapd, u8 *eid)
{
if (!hapd->iface->dfs_enable)
return eid;
*eid++ = WLAN_EID_PWR_CONSTRAINT;
*eid++ = 1;
*eid++ = hapd->iface->pwr_const;
return eid;
}
static u8 * hostapd_eid_tpc_report(struct hostapd_data *hapd, u8 *eid)
{
if (!hapd->iface->dfs_enable)
return eid;
*eid++ = WLAN_EID_TPC_REPORT;
*eid++ = 2;
*eid++ = hapd->iface->tx_power; /* TX POWER */
*eid++ = 0; /* Link Margin */
return eid;
}
static u8 * hostapd_eid_channel_switch(struct hostapd_data *hapd, u8 *eid)
{
if (!hapd->iface->dfs_enable || !hapd->iface->channel_switch)
return eid;
*eid++ = WLAN_EID_CHANNEL_SWITCH;
*eid++ = 3;
*eid++ = CHAN_SWITCH_MODE_QUIET;
*eid++ = hapd->iface->channel_switch; /* New channel */
/* 0 - very soon; 1 - before next TBTT; num - after num beacons */
*eid++ = 0;
return eid;
}
static u8 * hostapd_eid_wpa(struct hostapd_data *hapd, u8 *eid, size_t len,
struct sta_info *sta)
{
const u8 *ie;
size_t ielen;
ie = wpa_auth_get_wpa_ie(hapd->wpa_auth, &ielen);
if (ie == NULL || ielen > len)
return eid;
os_memcpy(eid, ie, ielen);
return eid + ielen;
}
void handle_probe_req(struct hostapd_data *hapd, struct ieee80211_mgmt *mgmt,
size_t len)
{
struct ieee80211_mgmt *resp;
struct ieee802_11_elems elems;
char *ssid;
u8 *pos, *epos, *ie;
size_t ssid_len, ie_len;
struct sta_info *sta = NULL;
ie = mgmt->u.probe_req.variable;
ie_len = len - (IEEE80211_HDRLEN + sizeof(mgmt->u.probe_req));
if (!hapd->iconf->send_probe_response)
return;
if (ieee802_11_parse_elems(hapd, ie, ie_len, &elems, 0) == ParseFailed)
{
wpa_printf(MSG_DEBUG, "Could not parse ProbeReq from " MACSTR,
MAC2STR(mgmt->sa));
return;
}
ssid = NULL;
ssid_len = 0;
if ((!elems.ssid || !elems.supp_rates)) {
wpa_printf(MSG_DEBUG, "STA " MACSTR " sent probe request "
"without SSID or supported rates element",
MAC2STR(mgmt->sa));
return;
}
if (hapd->conf->ignore_broadcast_ssid && elems.ssid_len == 0) {
wpa_printf(MSG_MSGDUMP, "Probe Request from " MACSTR " for "
"broadcast SSID ignored", MAC2STR(mgmt->sa));
return;
}
sta = ap_get_sta(hapd, mgmt->sa);
if (elems.ssid_len == 0 ||
(elems.ssid_len == hapd->conf->ssid.ssid_len &&
os_memcmp(elems.ssid, hapd->conf->ssid.ssid, elems.ssid_len) ==
0)) {
ssid = hapd->conf->ssid.ssid;
ssid_len = hapd->conf->ssid.ssid_len;
if (sta)
sta->ssid_probe = &hapd->conf->ssid;
}
if (!ssid) {
if (!(mgmt->da[0] & 0x01)) {
char ssid_txt[33];
ieee802_11_print_ssid(ssid_txt, elems.ssid,
elems.ssid_len);
wpa_printf(MSG_MSGDUMP, "Probe Request from " MACSTR
" for foreign SSID '%s'",
MAC2STR(mgmt->sa), ssid_txt);
}
return;
}
/* TODO: verify that supp_rates contains at least one matching rate
* with AP configuration */
#define MAX_PROBERESP_LEN 768
resp = os_zalloc(MAX_PROBERESP_LEN);
if (resp == NULL)
return;
epos = ((u8 *) resp) + MAX_PROBERESP_LEN;
resp->frame_control = IEEE80211_FC(WLAN_FC_TYPE_MGMT,
WLAN_FC_STYPE_PROBE_RESP);
os_memcpy(resp->da, mgmt->sa, ETH_ALEN);
os_memcpy(resp->sa, hapd->own_addr, ETH_ALEN);
os_memcpy(resp->bssid, hapd->own_addr, ETH_ALEN);
resp->u.probe_resp.beacon_int =
host_to_le16(hapd->iconf->beacon_int);
/* hardware or low-level driver will setup seq_ctrl and timestamp */
resp->u.probe_resp.capab_info =
host_to_le16(hostapd_own_capab_info(hapd, sta, 1));
pos = resp->u.probe_resp.variable;
*pos++ = WLAN_EID_SSID;
*pos++ = ssid_len;
os_memcpy(pos, ssid, ssid_len);
pos += ssid_len;
/* Supported rates */
pos = hostapd_eid_supp_rates(hapd, pos);
/* DS Params */
pos = hostapd_eid_ds_params(hapd, pos);
pos = hostapd_eid_country(hapd, pos, epos - pos);
pos = hostapd_eid_power_constraint(hapd, pos);
pos = hostapd_eid_tpc_report(hapd, pos);
/* ERP Information element */
pos = hostapd_eid_erp_info(hapd, pos);
/* Extended supported rates */
pos = hostapd_eid_ext_supp_rates(hapd, pos);
pos = hostapd_eid_wpa(hapd, pos, epos - pos, sta);
/* Wi-Fi Wireless Multimedia Extensions */
if (hapd->conf->wme_enabled)
pos = hostapd_eid_wme(hapd, pos);
if (hostapd_send_mgmt_frame(hapd, resp, pos - (u8 *) resp, 0) < 0)
perror("handle_probe_req: send");
os_free(resp);
wpa_printf(MSG_MSGDUMP, "STA " MACSTR " sent probe request for %s "
"SSID", MAC2STR(mgmt->sa),
elems.ssid_len == 0 ? "broadcast" : "our");
}
void ieee802_11_set_beacon(struct hostapd_data *hapd)
{
struct ieee80211_mgmt *head;
u8 *pos, *tail, *tailpos;
int preamble;
u16 capab_info;
size_t head_len, tail_len;
int cts_protection = ((ieee802_11_erp_info(hapd) &
ERP_INFO_USE_PROTECTION) ? 1 : 0);
#define BEACON_HEAD_BUF_SIZE 256
#define BEACON_TAIL_BUF_SIZE 512
head = os_zalloc(BEACON_HEAD_BUF_SIZE);
tailpos = tail = os_malloc(BEACON_TAIL_BUF_SIZE);
if (head == NULL || tail == NULL) {
wpa_printf(MSG_ERROR, "Failed to set beacon data");
os_free(head);
os_free(tail);
return;
}
head->frame_control = IEEE80211_FC(WLAN_FC_TYPE_MGMT,
WLAN_FC_STYPE_BEACON);
head->duration = host_to_le16(0);
os_memset(head->da, 0xff, ETH_ALEN);
os_memcpy(head->sa, hapd->own_addr, ETH_ALEN);
os_memcpy(head->bssid, hapd->own_addr, ETH_ALEN);
head->u.beacon.beacon_int =
host_to_le16(hapd->iconf->beacon_int);
/* hardware or low-level driver will setup seq_ctrl and timestamp */
capab_info = hostapd_own_capab_info(hapd, NULL, 0);
head->u.beacon.capab_info = host_to_le16(capab_info);
pos = &head->u.beacon.variable[0];
/* SSID */
*pos++ = WLAN_EID_SSID;
if (hapd->conf->ignore_broadcast_ssid == 2) {
/* clear the data, but keep the correct length of the SSID */
*pos++ = hapd->conf->ssid.ssid_len;
os_memset(pos, 0, hapd->conf->ssid.ssid_len);
pos += hapd->conf->ssid.ssid_len;
} else if (hapd->conf->ignore_broadcast_ssid) {
*pos++ = 0; /* empty SSID */
} else {
*pos++ = hapd->conf->ssid.ssid_len;
os_memcpy(pos, hapd->conf->ssid.ssid,
hapd->conf->ssid.ssid_len);
pos += hapd->conf->ssid.ssid_len;
}
/* Supported rates */
pos = hostapd_eid_supp_rates(hapd, pos);
/* DS Params */
pos = hostapd_eid_ds_params(hapd, pos);
head_len = pos - (u8 *) head;
tailpos = hostapd_eid_country(hapd, tailpos,
tail + BEACON_TAIL_BUF_SIZE - tailpos);
tailpos = hostapd_eid_power_constraint(hapd, tailpos);
tailpos = hostapd_eid_channel_switch(hapd, tailpos);
tailpos = hostapd_eid_tpc_report(hapd, tailpos);
/* ERP Information element */
tailpos = hostapd_eid_erp_info(hapd, tailpos);
/* Extended supported rates */
tailpos = hostapd_eid_ext_supp_rates(hapd, tailpos);
tailpos = hostapd_eid_wpa(hapd, tailpos, tail + BEACON_TAIL_BUF_SIZE -
tailpos, NULL);
/* Wi-Fi Wireless Multimedia Extensions */
if (hapd->conf->wme_enabled)
tailpos = hostapd_eid_wme(hapd, tailpos);
tail_len = tailpos > tail ? tailpos - tail : 0;
if (hostapd_set_beacon(hapd->conf->iface, hapd, (u8 *) head, head_len,
tail, tail_len))
wpa_printf(MSG_ERROR, "Failed to set beacon head/tail");
os_free(tail);
os_free(head);
if (hostapd_set_cts_protect(hapd, cts_protection))
wpa_printf(MSG_ERROR, "Failed to set CTS protect in kernel "
"driver");
if (hapd->iface->current_mode &&
hapd->iface->current_mode->mode == HOSTAPD_MODE_IEEE80211G &&
hostapd_set_short_slot_time(hapd,
hapd->iface->num_sta_no_short_slot_time
> 0 ? 0 : 1))
wpa_printf(MSG_ERROR, "Failed to set Short Slot Time option "
"in kernel driver");
if (hapd->iface->num_sta_no_short_preamble == 0 &&
hapd->iconf->preamble == SHORT_PREAMBLE)
preamble = SHORT_PREAMBLE;
else
preamble = LONG_PREAMBLE;
if (hostapd_set_preamble(hapd, preamble))
wpa_printf(MSG_ERROR, "Could not set preamble for kernel "
"driver");
}
void ieee802_11_set_beacons(struct hostapd_iface *iface)
{
size_t i;
for (i = 0; i < iface->num_bss; i++)
ieee802_11_set_beacon(iface->bss[i]);
}
#endif /* CONFIG_NATIVE_WINDOWS */