From: Johannes Berg <johannes.berg@xxxxxxxxx>
In interoperability testing some APs showed bad behaviour
if some of the VHT capabilities of the station are better
than their own. Restrict the assoc request parameters
- beamformee capabable,
- RX STBC and
- RX MCS set
to the subset that the AP can support.
Signed-off-by: Johannes Berg <johannes.berg@xxxxxxxxx>
---
net/mac80211/ieee80211_i.h | 2 ++
net/mac80211/mlme.c | 51 +++++++++++++++++++++++++++++++++++++++++++---
2 files changed, 50 insertions(+), 3 deletions(-)
diff --git a/net/mac80211/ieee80211_i.h b/net/mac80211/ieee80211_i.h
index f148cfa..6f36ab7 100644
--- a/net/mac80211/ieee80211_i.h
+++ b/net/mac80211/ieee80211_i.h
@@ -409,6 +409,8 @@ struct ieee80211_mgd_assoc_data {
u8 ap_ht_param;
+ struct ieee80211_vht_cap ap_vht_cap;
+
size_t ie_len;
u8 ie[];
};
diff --git a/net/mac80211/mlme.c b/net/mac80211/mlme.c
index 22e98de..508fa25 100644
--- a/net/mac80211/mlme.c
+++ b/net/mac80211/mlme.c
@@ -341,11 +341,13 @@ static void ieee80211_add_ht_ie(struct ieee80211_sub_if_data *sdata,
static void ieee80211_add_vht_ie(struct ieee80211_sub_if_data *sdata,
struct sk_buff *skb,
- struct ieee80211_supported_band *sband)
+ struct ieee80211_supported_band *sband,
+ struct ieee80211_vht_cap *ap_vht_cap)
{
u8 *pos;
u32 cap;
struct ieee80211_sta_vht_cap vht_cap;
+ int i;
BUILD_BUG_ON(sizeof(vht_cap) != sizeof(sband->vht_cap));
@@ -364,6 +366,42 @@ static void ieee80211_add_vht_ie(struct ieee80211_sub_if_data *sdata,
cap &= ~IEEE80211_VHT_CAP_SUPP_CHAN_WIDTH_160MHZ;
}
+ /*
+ * Some APs apparently get confused if our capabilities are better
+ * than theirs, so restrict what we advertise in the assoc request.
+ */
+ if (!(ap_vht_cap->vht_cap_info &
+ cpu_to_le32(IEEE80211_VHT_CAP_SU_BEAMFORMER_CAPABLE)))
+ cap &= ~IEEE80211_VHT_CAP_SU_BEAMFORMEE_CAPABLE;
+
+ if (!(ap_vht_cap->vht_cap_info &
+ cpu_to_le32(IEEE80211_VHT_CAP_TXSTBC)))
+ cap &= ~(IEEE80211_VHT_CAP_RXSTBC_1 |
+ IEEE80211_VHT_CAP_RXSTBC_3 |
+ IEEE80211_VHT_CAP_RXSTBC_4);
+
+ for (i = 0; i < 8; i++) {
+ int shift = i * 2;
+ u16 mask = IEEE80211_VHT_MCS_NOT_SUPPORTED << shift;
+ u16 ap_mcs, our_mcs;
+
+ ap_mcs = (le16_to_cpu(ap_vht_cap->supp_mcs.tx_mcs_map) &
+ mask) >> shift;
+ our_mcs = (le16_to_cpu(vht_cap.vht_mcs.rx_mcs_map) &
+ mask) >> shift;
+
+ switch (ap_mcs) {
+ default:
+ if (our_mcs <= ap_mcs)
+ break;
+ /* fall through */
+ case IEEE80211_VHT_MCS_NOT_SUPPORTED:
+ vht_cap.vht_mcs.rx_mcs_map &= cpu_to_le16(~mask);
+ vht_cap.vht_mcs.rx_mcs_map |=
+ cpu_to_le16(ap_mcs << shift);
+ }
+ }
+
/* reserve and fill IE */
pos = skb_put(skb, sizeof(struct ieee80211_vht_cap) + 2);
ieee80211_ie_build_vht_cap(pos, &vht_cap, cap);
@@ -562,7 +600,8 @@ static void ieee80211_send_assoc(struct ieee80211_sub_if_data *sdata)
sband, chan, sdata->smps_mode);
if (!(ifmgd->flags & IEEE80211_STA_DISABLE_VHT))
- ieee80211_add_vht_ie(sdata, skb, sband);
+ ieee80211_add_vht_ie(sdata, skb, sband,
+ &assoc_data->ap_vht_cap);
/* if present, add any custom non-vendor IEs that go after HT */
if (assoc_data->ie_len && assoc_data->ie) {
@@ -3770,7 +3809,7 @@ int ieee80211_mgd_assoc(struct ieee80211_sub_if_data *sdata,
struct ieee80211_bss *bss = (void *)req->bss->priv;
struct ieee80211_mgd_assoc_data *assoc_data;
struct ieee80211_supported_band *sband;
- const u8 *ssidie, *ht_ie;
+ const u8 *ssidie, *ht_ie, *vht_ie;
int i, err;
assoc_data = kzalloc(sizeof(*assoc_data) + req->ie_len, GFP_KERNEL);
@@ -3889,6 +3928,12 @@ int ieee80211_mgd_assoc(struct ieee80211_sub_if_data *sdata,
((struct ieee80211_ht_operation *)(ht_ie + 2))->ht_param;
else
ifmgd->flags |= IEEE80211_STA_DISABLE_HT;
+ vht_ie = ieee80211_bss_get_ie(req->bss, WLAN_EID_VHT_CAPABILITY);
+ if (vht_ie && vht_ie[1] >= sizeof(struct ieee80211_vht_cap))
+ memcpy(&assoc_data->ap_vht_cap, vht_ie + 2,
+ sizeof(struct ieee80211_vht_cap));
+ else
+ ifmgd->flags |= IEEE80211_STA_DISABLE_VHT;
rcu_read_unlock();
if (bss->wmm_used && bss->uapsd_supported &&
--
1.8.0
--
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