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Validate HT40 channel pair validity based on IEEE 802.11n Annex J

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Jouni Malinen 2008-11-25 12:51:03 +02:00 committed by Jouni Malinen
parent d6c9d4740b
commit 3e0cb2c503
1 changed files with 72 additions and 0 deletions
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72
hostapd/hw_features.c
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@ -170,6 +170,73 @@ static int hostapd_prepare_rates(struct hostapd_data *hapd,
}
#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;
}
#endif /* CONFIG_IEEE80211N */
/**
* hostapd_select_hw_mode - Select the hardware mode
* @iface: Pointer to interface data.
@ -233,6 +300,11 @@ int hostapd_select_hw_mode(struct hostapd_iface *iface)
return -1;
}
#ifdef CONFIG_IEEE80211N
if (!ieee80211n_allowed_ht40_channel_pair(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,