From 7b56a45fe866f62e47c04e1dabb32b1240297ed6 Mon Sep 17 00:00:00 2001
From: alainlamar <alainlamar@users.noreply.github.com>
Date: Sun, 5 Apr 2020 18:19:23 +0200
Subject: wireless: T2212: bugfix for BF-ANTENNA and SOUNDING-DIMENSION flags

VHT flags deal with many variables which depend on antenna count and
supported features. BF-ANTENNA-(2|3|4) and SOUNDING-DIMENSION-(2|3|4)
were not dealt with correctly.

IEEE 802.11ac (VHT) supports at least 1 antenna and up to 8 antennas
at most. The hsotapd VHT flags may support as many but most do not.
Therefore, we need to be picky here...
---
 data/templates/wifi/hostapd.conf.tmpl            | 14 +++++++++++++-
 interface-definitions/interfaces-wireless.xml.in |  4 ++--
 src/conf_mode/interfaces-wireless.py             |  4 ++++
 3 files changed, 19 insertions(+), 3 deletions(-)

diff --git a/data/templates/wifi/hostapd.conf.tmpl b/data/templates/wifi/hostapd.conf.tmpl
index bd2132b27..2884110d4 100644
--- a/data/templates/wifi/hostapd.conf.tmpl
+++ b/data/templates/wifi/hostapd.conf.tmpl
@@ -391,14 +391,26 @@ vht_capab=
 {%- endif -%}
 
 {%- if cap_vht_antenna_cnt -%}
+{%- if cap_vht_antenna_cnt|int > 1 -%}
+{%- if cap_vht_beamform -%}
 {%- for beamform in cap_vht_beamform -%}
 {%- if 'single-user-beamformer' in beamform -%}
+{%- if cap_vht_antenna_cnt|int < 6 -%}
 [BF-ANTENNA-{{ cap_vht_antenna_cnt|int -1 }}][SOUNDING-DIMENSION-{{ cap_vht_antenna_cnt|int -1}}]
+{%- endif -%}
 {%- else -%}
+{%- if cap_vht_antenna_cnt|int < 5 -%}
 [BF-ANTENNA-{{ cap_vht_antenna_cnt }}][SOUNDING-DIMENSION-{{ cap_vht_antenna_cnt }}]
 {%- endif -%}
+{%- endif -%}
 {%- endfor -%}
-{%- endif %}
+{%- else -%}
+{%- if cap_vht_antenna_cnt|int < 5 -%}
+[BF-ANTENNA-{{ cap_vht_antenna_cnt }}][SOUNDING-DIMENSION-{{ cap_vht_antenna_cnt }}]
+{%- endif -%}
+{%- endif -%}
+{%- endif -%}
+{%- endif -%}
 
 # ieee80211n: Whether IEEE 802.11n (HT) is enabled
 # 0 = disabled (default)
diff --git a/interface-definitions/interfaces-wireless.xml.in b/interface-definitions/interfaces-wireless.xml.in
index 490e63a42..194669f77 100644
--- a/interface-definitions/interfaces-wireless.xml.in
+++ b/interface-definitions/interfaces-wireless.xml.in
@@ -208,11 +208,11 @@
                     <properties>
                       <help>Number of antennas on this card</help>
                       <valueHelp>
-                        <format>1-9</format>
+                        <format>1-8</format>
                         <description>Number of antennas for this card</description>
                       </valueHelp>
                       <constraint>
-                        <validator name="numeric" argument="--range 1-9"/>
+                        <validator name="numeric" argument="--range 1-8"/>
                       </constraint>
                     </properties>
                   </leafNode>
diff --git a/src/conf_mode/interfaces-wireless.py b/src/conf_mode/interfaces-wireless.py
index bf8552bc1..da8470f7e 100755
--- a/src/conf_mode/interfaces-wireless.py
+++ b/src/conf_mode/interfaces-wireless.py
@@ -584,6 +584,10 @@ def verify(wifi):
     if wifi['cap_vht_beamform'] and wifi['cap_vht_antenna_cnt'] == 1:
         raise ConfigError('Cannot use beam forming with just one antenna!')
 
+    if wifi['cap_vht_beamform'] == 'single-user-beamformer' and wifi['cap_vht_antenna_cnt'] < 3:
+        # Nasty Gotcha: see https://w1.fi/cgit/hostap/plain/hostapd/hostapd.conf lines 692-705
+        raise ConfigError('Single-user beam former requires at least 3 antennas!')
+
     if wifi['sec_wep'] and (len(wifi['sec_wep_key']) == 0):
         raise ConfigError('Missing WEP keys')
 
-- 
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