mac80211: fix wrong 160/80+80 MHz setting

Before this patch, STA's would set new width of 160/80+80 MHz based on AP capability only.
This is wrong because STA may not support > 80MHz BW.
Fix is to verify STA has 160/80+80 MHz capability before increasing its width to > 80MHz.

The "support_80_80" and "support_160" setting is based on:
"Table 9-272 — Setting of the Supported Channel Width Set subfield and Extended NSS BW
Support subfield at a STA transmitting the VHT Capabilities Information field"
From "Draft P802.11REVmd_D3.0.pdf"

Signed-off-by: Aviad Brikman <aviad.brikman@celeno.com>
Signed-off-by: Shay Bar <shay.bar@celeno.com>
Link: https://lore.kernel.org/r/20200210130728.23674-1-shay.bar@celeno.com
Signed-off-by: Johannes Berg <johannes.berg@intel.com>

diff --git a/net/mac80211/util.c b/net/mac80211/util.c
index 739e905..decd46b 100644 (file)
--- a/net/mac80211/util.c
+++ b/net/mac80211/util.c
@@ -2993,10 +2993,22 @@ bool ieee80211_chandef_vht_oper(struct ieee80211_hw *hw,
        int cf0, cf1;
        int ccfs0, ccfs1, ccfs2;
        int ccf0, ccf1;
+       u32 vht_cap;
+       bool support_80_80 = false;
+       bool support_160 = false;
 
        if (!oper || !htop)
                return false;
 
+       vht_cap = hw->wiphy->bands[chandef->chan->band]->vht_cap.cap;
+       support_160 = (vht_cap & (IEEE80211_VHT_CAP_SUPP_CHAN_WIDTH_MASK |
+                                 IEEE80211_VHT_CAP_EXT_NSS_BW_MASK));
+       support_80_80 = ((vht_cap &
+                        IEEE80211_VHT_CAP_SUPP_CHAN_WIDTH_160_80PLUS80MHZ) ||
+                       (vht_cap & IEEE80211_VHT_CAP_SUPP_CHAN_WIDTH_160MHZ &&
+                        vht_cap & IEEE80211_VHT_CAP_EXT_NSS_BW_MASK) ||
+                       ((vht_cap & IEEE80211_VHT_CAP_EXT_NSS_BW_MASK) >>
+                                   IEEE80211_VHT_CAP_EXT_NSS_BW_SHIFT > 1));
        ccfs0 = oper->center_freq_seg0_idx;
        ccfs1 = oper->center_freq_seg1_idx;
        ccfs2 = (le16_to_cpu(htop->operation_mode) &
@@ -3024,10 +3036,10 @@ bool ieee80211_chandef_vht_oper(struct ieee80211_hw *hw,
                        unsigned int diff;
 
                        diff = abs(ccf1 - ccf0);
-                       if (diff == 8) {
+                       if ((diff == 8) && support_160) {
                                new.width = NL80211_CHAN_WIDTH_160;
                                new.center_freq1 = cf1;
-                       } else if (diff > 8) {
+                       } else if ((diff > 8) && support_80_80) {
                                new.width = NL80211_CHAN_WIDTH_80P80;
                                new.center_freq2 = cf1;
                        }