nl80211: advertise HT/VHT channel limitations

When drivers or regulatory have limitations on
40, 80 or 160 MHz channels, advertise these to
userspace via nl80211. Also add a new feature
flag to let userspace know this is supported.

Signed-off-by: Johannes Berg <johannes.berg@intel.com>

2 files changed, 14 insertions, 1 deletions

diff --git a/net/wireless/core.c b/net/wireless/core.c
index 922002105062..33b75b9b8efa 100644
--- a/net/wireless/core.c
+++ b/net/wireless/core.c
@@ -367,7 +367,8 @@ struct wiphy *wiphy_new(const struct cfg80211_ops *ops, int sizeof_priv)
         rdev->wiphy.rts_threshold = (u32) -1;
         rdev->wiphy.coverage_class = 0;
 
-        rdev->wiphy.features = NL80211_FEATURE_SCAN_FLUSH;
+        rdev->wiphy.features = NL80211_FEATURE_SCAN_FLUSH |
+                               NL80211_FEATURE_ADVERTISE_CHAN_LIMITS;
 
         return &rdev->wiphy;
 }
diff --git a/net/wireless/nl80211.c b/net/wireless/nl80211.c
index c1e18ccf4049..7e40b9e82b45 100644
--- a/net/wireless/nl80211.c
+++ b/net/wireless/nl80211.c
@@ -562,6 +562,18 @@ static int nl80211_msg_put_channel(struct sk_buff *msg,
                 if (nla_put_u32(msg, NL80211_FREQUENCY_ATTR_DFS_TIME, time))
                         goto nla_put_failure;
         }
+        if ((chan->flags & IEEE80211_CHAN_NO_HT40MINUS) &&
+            nla_put_flag(msg, NL80211_FREQUENCY_ATTR_NO_HT40_MINUS))
+                goto nla_put_failure;
+        if ((chan->flags & IEEE80211_CHAN_NO_HT40PLUS) &&
+            nla_put_flag(msg, NL80211_FREQUENCY_ATTR_NO_HT40_PLUS))
+                goto nla_put_failure;
+        if ((chan->flags & IEEE80211_CHAN_NO_80MHZ) &&
+            nla_put_flag(msg, NL80211_FREQUENCY_ATTR_NO_80MHZ))
+                goto nla_put_failure;
+        if ((chan->flags & IEEE80211_CHAN_NO_160MHZ) &&
+            nla_put_flag(msg, NL80211_FREQUENCY_ATTR_NO_160MHZ))
+                goto nla_put_failure;
 
         if (nla_put_u32(msg, NL80211_FREQUENCY_ATTR_MAX_TX_POWER,
                         DBM_TO_MBM(chan->max_power)))