hostap/hostapd/hw_features.c
Jouni Malinen 5eb4e3d024 802.11n: scan for overlapping BSSes before starting 20/40 MHz channel
Try to match PRI/SEC channel with neighboring 20/40 MHz BSSes per
IEEE 802.11n/D7.0 11.14.3.2. This is not yet complete implementation,
but at least some parts of the 40 MHz coex are improved.

40 MHz operation maybe rejected (i.e., fall back to using 20 MHz) or
pri/sec channels may be switched if needed.
2009-02-04 21:19:54 +02:00

644 lines
16 KiB
C

/*
* hostapd / Hardware feature query and different modes
* Copyright 2002-2003, Instant802 Networks, Inc.
* Copyright 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"
#include "hostapd.h"
#include "hw_features.h"
#include "driver_i.h"
#include "config.h"
void hostapd_free_hw_features(struct hostapd_hw_modes *hw_features,
size_t num_hw_features)
{
size_t i;
if (hw_features == NULL)
return;
for (i = 0; i < num_hw_features; i++) {
os_free(hw_features[i].channels);
os_free(hw_features[i].rates);
}
os_free(hw_features);
}
int hostapd_get_hw_features(struct hostapd_iface *iface)
{
struct hostapd_data *hapd = iface->bss[0];
int ret = 0, i, j;
u16 num_modes, flags;
struct hostapd_hw_modes *modes;
if (hostapd_drv_none(hapd))
return -1;
modes = hostapd_get_hw_feature_data(hapd, &num_modes, &flags);
if (modes == NULL) {
hostapd_logger(hapd, NULL, HOSTAPD_MODULE_IEEE80211,
HOSTAPD_LEVEL_DEBUG,
"Fetching hardware channel/rate support not "
"supported.");
return -1;
}
iface->hw_flags = flags;
hostapd_free_hw_features(iface->hw_features, iface->num_hw_features);
iface->hw_features = modes;
iface->num_hw_features = num_modes;
for (i = 0; i < num_modes; i++) {
struct hostapd_hw_modes *feature = &modes[i];
/* set flag for channels we can use in current regulatory
* domain */
for (j = 0; j < feature->num_channels; j++) {
/*
* Disable all channels that are marked not to allow
* IBSS operation or active scanning. In addition,
* disable all channels that require radar detection,
* since that (in addition to full DFS) is not yet
* supported.
*/
if (feature->channels[j].flag &
(HOSTAPD_CHAN_NO_IBSS |
HOSTAPD_CHAN_PASSIVE_SCAN |
HOSTAPD_CHAN_RADAR))
feature->channels[j].flag |=
HOSTAPD_CHAN_DISABLED;
if (feature->channels[j].flag & HOSTAPD_CHAN_DISABLED)
continue;
wpa_printf(MSG_MSGDUMP, "Allowed channel: mode=%d "
"chan=%d freq=%d MHz max_tx_power=%d dBm",
feature->mode,
feature->channels[j].chan,
feature->channels[j].freq,
feature->channels[j].max_tx_power);
}
}
return ret;
}
static int hostapd_prepare_rates(struct hostapd_data *hapd,
struct hostapd_hw_modes *mode)
{
int i, num_basic_rates = 0;
int basic_rates_a[] = { 60, 120, 240, -1 };
int basic_rates_b[] = { 10, 20, -1 };
int basic_rates_g[] = { 10, 20, 55, 110, -1 };
int *basic_rates;
if (hapd->iconf->basic_rates)
basic_rates = hapd->iconf->basic_rates;
else switch (mode->mode) {
case HOSTAPD_MODE_IEEE80211A:
basic_rates = basic_rates_a;
break;
case HOSTAPD_MODE_IEEE80211B:
basic_rates = basic_rates_b;
break;
case HOSTAPD_MODE_IEEE80211G:
basic_rates = basic_rates_g;
break;
default:
return -1;
}
if (hostapd_set_rate_sets(hapd, hapd->iconf->supported_rates,
basic_rates, mode->mode)) {
wpa_printf(MSG_ERROR, "Failed to update rate sets in kernel "
"module");
}
os_free(hapd->iface->current_rates);
hapd->iface->num_rates = 0;
hapd->iface->current_rates =
os_malloc(mode->num_rates * sizeof(struct hostapd_rate_data));
if (!hapd->iface->current_rates) {
wpa_printf(MSG_ERROR, "Failed to allocate memory for rate "
"table.");
return -1;
}
for (i = 0; i < mode->num_rates; i++) {
struct hostapd_rate_data *rate;
if (hapd->iconf->supported_rates &&
!hostapd_rate_found(hapd->iconf->supported_rates,
mode->rates[i].rate))
continue;
rate = &hapd->iface->current_rates[hapd->iface->num_rates];
os_memcpy(rate, &mode->rates[i],
sizeof(struct hostapd_rate_data));
if (hostapd_rate_found(basic_rates, rate->rate)) {
rate->flags |= HOSTAPD_RATE_BASIC;
num_basic_rates++;
} else
rate->flags &= ~HOSTAPD_RATE_BASIC;
wpa_printf(MSG_DEBUG, "RATE[%d] rate=%d flags=0x%x",
hapd->iface->num_rates, rate->rate, rate->flags);
hapd->iface->num_rates++;
}
if (hapd->iface->num_rates == 0 || num_basic_rates == 0) {
wpa_printf(MSG_ERROR, "No rates remaining in supported/basic "
"rate sets (%d,%d).",
hapd->iface->num_rates, num_basic_rates);
return -1;
}
return 0;
}
#ifdef CONFIG_IEEE80211N
static int ieee80211n_allowed_ht40_channel_pair(struct hostapd_iface *iface)
{
int sec_chan, ok, j, first;
int allowed[] = { 36, 44, 52, 60, 100, 108, 116, 124, 132, 149, 157,
184, 192 };
size_t k;
if (!iface->conf->secondary_channel)
return 1; /* HT40 not used */
sec_chan = iface->conf->channel + iface->conf->secondary_channel * 4;
wpa_printf(MSG_DEBUG, "HT40: control channel: %d "
"secondary channel: %d",
iface->conf->channel, sec_chan);
/* Verify that HT40 secondary channel is an allowed 20 MHz
* channel */
ok = 0;
for (j = 0; j < iface->current_mode->num_channels; j++) {
struct hostapd_channel_data *chan =
&iface->current_mode->channels[j];
if (!(chan->flag & HOSTAPD_CHAN_DISABLED) &&
chan->chan == sec_chan) {
ok = 1;
break;
}
}
if (!ok) {
wpa_printf(MSG_ERROR, "HT40 secondary channel %d not allowed",
sec_chan);
return 0;
}
/*
* Verify that HT40 primary,secondary channel pair is allowed per
* IEEE 802.11n Annex J. This is only needed for 5 GHz band since
* 2.4 GHz rules allow all cases where the secondary channel fits into
* the list of allowed channels (already checked above).
*/
if (iface->current_mode->mode != HOSTAPD_MODE_IEEE80211A)
return 1;
if (iface->conf->secondary_channel > 0)
first = iface->conf->channel;
else
first = sec_chan;
ok = 0;
for (k = 0; k < sizeof(allowed) / sizeof(allowed[0]); k++) {
if (first == allowed[k]) {
ok = 1;
break;
}
}
if (!ok) {
wpa_printf(MSG_ERROR, "HT40 channel pair (%d, %d) not allowed",
iface->conf->channel,
iface->conf->secondary_channel);
return 0;
}
return 1;
}
static void ieee80211n_switch_pri_sec(struct hostapd_iface *iface)
{
if (iface->conf->secondary_channel > 0) {
iface->conf->channel += 4;
iface->conf->secondary_channel = -1;
} else {
iface->conf->channel -= 4;
iface->conf->secondary_channel = 1;
}
}
static int ieee80211n_check_40mhz_5g(struct hostapd_iface *iface)
{
int pri_chan, sec_chan, pri_freq, sec_freq, pri_bss, sec_bss;
const struct hostapd_neighbor_bss *n;
size_t i, num;
int match;
pri_chan = iface->conf->channel;
sec_chan = iface->conf->secondary_channel * 4;
pri_freq = hostapd_hw_get_freq(iface->bss[0], pri_chan);
if (iface->conf->secondary_channel > 0)
sec_freq = pri_freq + 20;
else
sec_freq = pri_freq - 20;
n = hostapd_driver_get_neighbor_bss(iface->bss[0], &num);
/*
* Switch PRI/SEC channels if Beacons were detected on selected SEC
* channel, but not on selected PRI channel.
*/
pri_bss = sec_bss = 0;
for (i = 0; n && i < num; i++) {
if (n[i].freq == pri_freq)
pri_bss++;
else if (n[i].freq == sec_freq)
sec_bss++;
}
if (sec_bss && !pri_bss) {
wpa_printf(MSG_INFO, "Switch own primary and secondary "
"channel to get secondary channel with no Beacons "
"from other BSSes");
ieee80211n_switch_pri_sec(iface);
}
/*
* Match PRI/SEC channel with any existing HT40 BSS on the same
* channels that we are about to use (if already mixed order in
* existing BSSes, use own preference).
*/
match = 0;
for (i = 0; n && i < num; i++) {
if (pri_chan == n[i].pri_chan &&
sec_chan == n[i].sec_chan) {
match = 1;
break;
}
}
if (!match) {
for (i = 0; n && i < num; i++) {
if (pri_chan == n[i].sec_chan &&
sec_chan == n[i].pri_chan) {
wpa_printf(MSG_INFO, "Switch own primary and "
"secondary channel due to BSS "
"overlap with " MACSTR,
MAC2STR(n[i].bssid));
ieee80211n_switch_pri_sec(iface);
break;
}
}
}
return 1;
}
static int ieee80211n_check_40mhz_2g4(struct hostapd_iface *iface)
{
int pri_freq, sec_freq;
int affected_start, affected_end;
const struct hostapd_neighbor_bss *n;
size_t i, num;
pri_freq = hostapd_hw_get_freq(iface->bss[0], iface->conf->channel);
if (iface->conf->secondary_channel > 0)
sec_freq = pri_freq + 20;
else
sec_freq = pri_freq - 20;
affected_start = (pri_freq + sec_freq) / 2 - 25;
affected_end = (pri_freq + sec_freq) / 2 + 25;
wpa_printf(MSG_DEBUG, "40 MHz affected channel range: [%d,%d] MHz",
affected_start, affected_end);
n = hostapd_driver_get_neighbor_bss(iface->bss[0], &num);
for (i = 0; n && i < num; i++) {
int pri = n[i].freq;
int sec = pri;
if (n[i].sec_chan) {
if (n[i].sec_chan < n[i].pri_chan)
sec = pri - 20;
else
sec = pri + 20;
}
if ((pri < affected_start || pri > affected_end) &&
(sec < affected_start || sec > affected_end))
continue; /* not within affected channel range */
if (n[i].sec_chan) {
if (pri_freq != pri || sec_freq != sec) {
wpa_printf(MSG_DEBUG, "40 MHz pri/sec "
"mismatch with BSS " MACSTR
" <%d,%d> (chan=%d%c) vs. <%d,%d>",
MAC2STR(n[i].bssid),
pri, sec, n[i].pri_chan,
sec > pri ? '+' : '-',
pri_freq, sec_freq);
return 0;
}
}
/* TODO: 40 MHz intolerant */
}
return 1;
}
static void ieee80211n_check_40mhz(struct hostapd_iface *iface)
{
int oper40;
if (!iface->conf->secondary_channel)
return; /* HT40 not used */
/* Check list of neighboring BSSes (from scan) to see whether 40 MHz is
* allowed per IEEE 802.11n/D7.0, 11.14.3.2 */
if (iface->current_mode->mode == HOSTAPD_MODE_IEEE80211A)
oper40 = ieee80211n_check_40mhz_5g(iface);
else
oper40 = ieee80211n_check_40mhz_2g4(iface);
if (!oper40) {
wpa_printf(MSG_INFO, "20/40 MHz operation not permitted on "
"channel pri=%d sec=%d based on overlapping BSSes",
iface->conf->channel,
iface->conf->channel +
iface->conf->secondary_channel * 4);
iface->conf->secondary_channel = 0;
iface->conf->ht_capab &= ~HT_CAP_INFO_SUPP_CHANNEL_WIDTH_SET;
}
}
static int ieee80211n_supported_ht_capab(struct hostapd_iface *iface)
{
u16 hw = iface->current_mode->ht_capab;
u16 conf = iface->conf->ht_capab;
if (!iface->conf->ieee80211n)
return 1;
if ((conf & HT_CAP_INFO_LDPC_CODING_CAP) &&
!(hw & HT_CAP_INFO_LDPC_CODING_CAP)) {
wpa_printf(MSG_ERROR, "Driver does not support configured "
"HT capability [LDPC]");
return 0;
}
if ((conf & HT_CAP_INFO_SUPP_CHANNEL_WIDTH_SET) &&
!(hw & HT_CAP_INFO_SUPP_CHANNEL_WIDTH_SET)) {
wpa_printf(MSG_ERROR, "Driver does not support configured "
"HT capability [HT40*]");
return 0;
}
if ((conf & HT_CAP_INFO_SMPS_MASK) != (hw & HT_CAP_INFO_SMPS_MASK) &&
(conf & HT_CAP_INFO_SMPS_MASK) != HT_CAP_INFO_SMPS_DISABLED) {
wpa_printf(MSG_ERROR, "Driver does not support configured "
"HT capability [SMPS-*]");
return 0;
}
if ((conf & HT_CAP_INFO_GREEN_FIELD) &&
!(hw & HT_CAP_INFO_GREEN_FIELD)) {
wpa_printf(MSG_ERROR, "Driver does not support configured "
"HT capability [GF]");
return 0;
}
if ((conf & HT_CAP_INFO_SHORT_GI20MHZ) &&
!(hw & HT_CAP_INFO_SHORT_GI20MHZ)) {
wpa_printf(MSG_ERROR, "Driver does not support configured "
"HT capability [SHORT-GI-20]");
return 0;
}
if ((conf & HT_CAP_INFO_SHORT_GI40MHZ) &&
!(hw & HT_CAP_INFO_SHORT_GI40MHZ)) {
wpa_printf(MSG_ERROR, "Driver does not support configured "
"HT capability [SHORT-GI-40]");
return 0;
}
if ((conf & HT_CAP_INFO_TX_STBC) && !(hw & HT_CAP_INFO_TX_STBC)) {
wpa_printf(MSG_ERROR, "Driver does not support configured "
"HT capability [TX-STBC]");
return 0;
}
if ((conf & HT_CAP_INFO_RX_STBC_MASK) >
(hw & HT_CAP_INFO_RX_STBC_MASK)) {
wpa_printf(MSG_ERROR, "Driver does not support configured "
"HT capability [RX-STBC*]");
return 0;
}
if ((conf & HT_CAP_INFO_DELAYED_BA) &&
!(hw & HT_CAP_INFO_DELAYED_BA)) {
wpa_printf(MSG_ERROR, "Driver does not support configured "
"HT capability [DELAYED-BA]");
return 0;
}
if ((conf & HT_CAP_INFO_MAX_AMSDU_SIZE) &&
!(hw & HT_CAP_INFO_MAX_AMSDU_SIZE)) {
wpa_printf(MSG_ERROR, "Driver does not support configured "
"HT capability [MAX-AMSDU-7935]");
return 0;
}
if ((conf & HT_CAP_INFO_DSSS_CCK40MHZ) &&
!(hw & HT_CAP_INFO_DSSS_CCK40MHZ)) {
wpa_printf(MSG_ERROR, "Driver does not support configured "
"HT capability [DSSS_CCK-40]");
return 0;
}
if ((conf & HT_CAP_INFO_PSMP_SUPP) && !(hw & HT_CAP_INFO_PSMP_SUPP)) {
wpa_printf(MSG_ERROR, "Driver does not support configured "
"HT capability [PSMP]");
return 0;
}
if ((conf & HT_CAP_INFO_LSIG_TXOP_PROTECT_SUPPORT) &&
!(hw & HT_CAP_INFO_LSIG_TXOP_PROTECT_SUPPORT)) {
wpa_printf(MSG_ERROR, "Driver does not support configured "
"HT capability [LSIG-TXOP-PROT]");
return 0;
}
return 1;
}
#endif /* CONFIG_IEEE80211N */
/**
* hostapd_select_hw_mode - Select the hardware mode
* @iface: Pointer to interface data.
* Returns: 0 on success, -1 on failure
*
* Sets up the hardware mode, channel, rates, and passive scanning
* based on the configuration.
*/
int hostapd_select_hw_mode(struct hostapd_iface *iface)
{
int i, j, ok, ret;
if (iface->num_hw_features < 1)
return -1;
iface->current_mode = NULL;
for (i = 0; i < iface->num_hw_features; i++) {
struct hostapd_hw_modes *mode = &iface->hw_features[i];
if (mode->mode == (int) iface->conf->hw_mode) {
iface->current_mode = mode;
break;
}
}
if (iface->current_mode == NULL) {
wpa_printf(MSG_ERROR, "Hardware does not support configured "
"mode");
hostapd_logger(iface->bss[0], NULL, HOSTAPD_MODULE_IEEE80211,
HOSTAPD_LEVEL_WARNING,
"Hardware does not support configured mode "
"(%d)", (int) iface->conf->hw_mode);
return -1;
}
ok = 0;
for (j = 0; j < iface->current_mode->num_channels; j++) {
struct hostapd_channel_data *chan =
&iface->current_mode->channels[j];
if (!(chan->flag & HOSTAPD_CHAN_DISABLED) &&
(chan->chan == iface->conf->channel)) {
ok = 1;
break;
}
}
if (ok == 0 && iface->conf->channel != 0) {
hostapd_logger(iface->bss[0], NULL,
HOSTAPD_MODULE_IEEE80211,
HOSTAPD_LEVEL_WARNING,
"Configured channel (%d) not found from the "
"channel list of current mode (%d) %s",
iface->conf->channel,
iface->current_mode->mode,
hostapd_hw_mode_txt(iface->current_mode->mode));
iface->current_mode = NULL;
}
if (iface->current_mode == NULL) {
hostapd_logger(iface->bss[0], NULL, HOSTAPD_MODULE_IEEE80211,
HOSTAPD_LEVEL_WARNING,
"Hardware does not support configured channel");
return -1;
}
#ifdef CONFIG_IEEE80211N
ieee80211n_check_40mhz(iface);
if (!ieee80211n_allowed_ht40_channel_pair(iface))
return -1;
if (!ieee80211n_supported_ht_capab(iface))
return -1;
#endif /* CONFIG_IEEE80211N */
if (hostapd_prepare_rates(iface->bss[0], iface->current_mode)) {
wpa_printf(MSG_ERROR, "Failed to prepare rates table.");
hostapd_logger(iface->bss[0], NULL, HOSTAPD_MODULE_IEEE80211,
HOSTAPD_LEVEL_WARNING,
"Failed to prepare rates table.");
return -1;
}
ret = hostapd_passive_scan(iface->bss[0], 0,
iface->conf->passive_scan_mode,
iface->conf->passive_scan_interval,
iface->conf->passive_scan_listen,
NULL, NULL);
if (ret) {
if (ret == -1) {
wpa_printf(MSG_DEBUG, "Passive scanning not "
"supported");
} else {
wpa_printf(MSG_ERROR, "Could not set passive "
"scanning: %s", strerror(ret));
}
ret = 0;
}
return ret;
}
const char * hostapd_hw_mode_txt(int mode)
{
switch (mode) {
case HOSTAPD_MODE_IEEE80211A:
return "IEEE 802.11a";
case HOSTAPD_MODE_IEEE80211B:
return "IEEE 802.11b";
case HOSTAPD_MODE_IEEE80211G:
return "IEEE 802.11g";
default:
return "UNKNOWN";
}
}
int hostapd_hw_get_freq(struct hostapd_data *hapd, int chan)
{
int i;
if (!hapd->iface->current_mode)
return 0;
for (i = 0; i < hapd->iface->current_mode->num_channels; i++) {
struct hostapd_channel_data *ch =
&hapd->iface->current_mode->channels[i];
if (ch->chan == chan)
return ch->freq;
}
return 0;
}
int hostapd_hw_get_channel(struct hostapd_data *hapd, int freq)
{
int i;
if (!hapd->iface->current_mode)
return 0;
for (i = 0; i < hapd->iface->current_mode->num_channels; i++) {
struct hostapd_channel_data *ch =
&hapd->iface->current_mode->channels[i];
if (ch->freq == freq)
return ch->chan;
}
return 0;
}