mac80211: restrict assoc request VHT capabilities
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@intel.com>
diff --git a/net/mac80211/ieee80211_i.h b/net/mac80211/ieee80211_i.h
index c084c15..7182907 100644
--- a/net/mac80211/ieee80211_i.h
+++ b/net/mac80211/ieee80211_i.h
@@ -405,6 +405,8 @@
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 7d253a0..6ffbf70 100644
--- a/net/mac80211/mlme.c
+++ b/net/mac80211/mlme.c
@@ -341,11 +341,13 @@
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 @@
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 @@
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) {
@@ -3753,7 +3792,7 @@
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);
@@ -3872,6 +3911,12 @@
((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 &&