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mac80211: handle HT PHY BSS membership selector value correctly

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802.11n-2009 extends the supported rates element with a
magic value which can be used to prevent legacy stations
from joining the BSS.

However, this magic value is not a rate like the others
and the magic can simply be ignored/skipped at this late
stage.

Signed-off-by: Christian Lamparter <chunkeey@googlemail.com>---
Signed-off-by: John W. Linville <linville@tuxdriver.com>
This commit is contained in:
Christian Lamparter 2011-10-15 00:14:49 +02:00 committed by John W. Linville
parent fa5e91bc77
commit c74d084f91
2 changed files with 52 additions and 41 deletions
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3
include/linux/ieee80211.h
View File

@ -770,6 +770,9 @@ struct ieee80211_mgmt {
} u;
} __attribute__ ((packed));
/* Supported Rates value encodings in 802.11n-2009 7.3.2.2 */
#define BSS_MEMBERSHIP_SELECTOR_HT_PHY 127
/* mgmt header + 1 byte category code */
#define IEEE80211_MIN_ACTION_SIZE offsetof(struct ieee80211_mgmt, u.action.u)

90
net/mac80211/mlme.c
View File

@ -1466,6 +1466,47 @@ ieee80211_rx_mgmt_disassoc(struct ieee80211_sub_if_data *sdata,
return RX_MGMT_CFG80211_DISASSOC;
}
static void ieee80211_get_rates(struct ieee80211_supported_band *sband,
u8 *supp_rates, unsigned int supp_rates_len,
u32 *rates, u32 *basic_rates,
bool *have_higher_than_11mbit,
int *min_rate, int *min_rate_index)
{
int i, j;
for (i = 0; i < supp_rates_len; i++) {
int rate = (supp_rates[i] & 0x7f) * 5;
bool is_basic = !!(supp_rates[i] & 0x80);
if (rate > 110)
*have_higher_than_11mbit = true;
/*
* BSS_MEMBERSHIP_SELECTOR_HT_PHY is defined in 802.11n-2009
* 7.3.2.2 as a magic value instead of a rate. Hence, skip it.
*
* Note: Even through the membership selector and the basic
* rate flag share the same bit, they are not exactly
* the same.
*/
if (!!(supp_rates[i] & 0x80) &&
(supp_rates[i] & 0x7f) == BSS_MEMBERSHIP_SELECTOR_HT_PHY)
continue;
for (j = 0; j < sband->n_bitrates; j++) {
if (sband->bitrates[j].bitrate == rate) {
*rates |= BIT(j);
if (is_basic)
*basic_rates |= BIT(j);
if (rate < *min_rate) {
*min_rate = rate;
*min_rate_index = j;
}
break;
}
}
}
}
static bool ieee80211_assoc_success(struct ieee80211_work *wk,
struct ieee80211_mgmt *mgmt, size_t len)
@ -1482,7 +1523,7 @@ static bool ieee80211_assoc_success(struct ieee80211_work *wk,
struct ieee802_11_elems elems;
struct ieee80211_bss_conf *bss_conf = &sdata->vif.bss_conf;
u32 changed = 0;
int i, j, err;
int err;
bool have_higher_than_11mbit = false;
u16 ap_ht_cap_flags;
int min_rate = INT_MAX, min_rate_index = -1;
@ -1540,47 +1581,14 @@ static bool ieee80211_assoc_success(struct ieee80211_work *wk,
basic_rates = 0;
sband = local->hw.wiphy->bands[wk->chan->band];
for (i = 0; i < elems.supp_rates_len; i++) {
int rate = (elems.supp_rates[i] & 0x7f) * 5;
bool is_basic = !!(elems.supp_rates[i] & 0x80);
ieee80211_get_rates(sband, elems.supp_rates, elems.supp_rates_len,
&rates, &basic_rates, &have_higher_than_11mbit,
&min_rate, &min_rate_index);
if (rate > 110)
have_higher_than_11mbit = true;
for (j = 0; j < sband->n_bitrates; j++) {
if (sband->bitrates[j].bitrate == rate) {
rates |= BIT(j);
if (is_basic)
basic_rates |= BIT(j);
if (rate < min_rate) {
min_rate = rate;
min_rate_index = j;
}
break;
}
}
}
for (i = 0; i < elems.ext_supp_rates_len; i++) {
int rate = (elems.ext_supp_rates[i] & 0x7f) * 5;
bool is_basic = !!(elems.ext_supp_rates[i] & 0x80);
if (rate > 110)
have_higher_than_11mbit = true;
for (j = 0; j < sband->n_bitrates; j++) {
if (sband->bitrates[j].bitrate == rate) {
rates |= BIT(j);
if (is_basic)
basic_rates |= BIT(j);
if (rate < min_rate) {
min_rate = rate;
min_rate_index = j;
}
break;
}
}
}
ieee80211_get_rates(sband, elems.ext_supp_rates,
elems.ext_supp_rates_len, &rates, &basic_rates,
&have_higher_than_11mbit,
&min_rate, &min_rate_index);
/*
* some buggy APs don't advertise basic_rates. use the lowest