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Commit c74d084f authored by Christian Lamparter's avatar Christian Lamparter Committed by John W. Linville
Browse files

mac80211: handle HT PHY BSS membership selector value correctly 



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: default avatarChristian Lamparter <chunkeey@googlemail.com&gt;--->
Signed-off-by: default avatarJohn W. Linville <linville@tuxdriver.com>
parent fa5e91bc

include/linux/ieee80211.h

+3 −0
Original line number Diff line number Diff line
@@ -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)

net/mac80211/mlme.c

+49 −41
Original line number Diff line number Diff line
@@ -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);



		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);

	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;

			}

		}

	}

	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