cfg80211: Add attributes describing prohibited channel bandwidth

Since there are frequency bands (e.g. 5.9GHz) allowing channels
with only 10 or 5 MHz bandwidth, this patch adds attributes that
allow keeping track about this information.

When channel attributes are reported to user-space, make sure to
not break old tools, i.e. if the 'split wiphy dump' is enabled,
report the extra attributes (if present) describing the bandwidth
restrictions.  If the 'split wiphy dump' is not enabled,
completely omit those channels that have flags set to either
IEEE80211_CHAN_NO_10MHZ or IEEE80211_CHAN_NO_20MHZ.

Add the check for new bandwidth restriction flags in
cfg80211_chandef_usable() to comply with the restrictions.

Signed-off-by: Rostislav Lisovy <rostislav.lisovy@fel.cvut.cz>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>

2 files changed, 12 insertions, 0 deletions

diff --git a/include/net/cfg80211.h b/include/net/cfg80211.h
index 3dd2cb465540..c98cf08538b9 100644
--- a/include/net/cfg80211.h
+++ b/include/net/cfg80211.h
@@ -111,6 +111,10 @@ enum ieee80211_band {
  *      restrictions.
  * @IEEE80211_CHAN_INDOOR_ONLY: see %NL80211_FREQUENCY_ATTR_INDOOR_ONLY
  * @IEEE80211_CHAN_GO_CONCURRENT: see %NL80211_FREQUENCY_ATTR_GO_CONCURRENT
+ * @IEEE80211_CHAN_NO_20MHZ: 20 MHz bandwidth is not permitted
+ *      on this channel.
+ * @IEEE80211_CHAN_NO_10MHZ: 10 MHz bandwidth is not permitted
+ *      on this channel.
  *
  */
 enum ieee80211_channel_flags {
@@ -125,6 +129,8 @@ enum ieee80211_channel_flags {
         IEEE80211_CHAN_NO_160MHZ        = 1<<8,
         IEEE80211_CHAN_INDOOR_ONLY      = 1<<9,
         IEEE80211_CHAN_GO_CONCURRENT    = 1<<10,
+        IEEE80211_CHAN_NO_20MHZ         = 1<<11,
+        IEEE80211_CHAN_NO_10MHZ         = 1<<12,
 };
 
 #define IEEE80211_CHAN_NO_HT40 \
diff --git a/include/uapi/linux/nl80211.h b/include/uapi/linux/nl80211.h
index 513bfd7b2e5f..0592032ff160 100644
--- a/include/uapi/linux/nl80211.h
+++ b/include/uapi/linux/nl80211.h
@@ -2358,6 +2358,10 @@ enum nl80211_band_attr {
  *      connected to an AP with DFS and radar detection on the UNII band (it is
  *      up to user-space, i.e., wpa_supplicant to perform the required
  *      verifications)
+ * @NL80211_FREQUENCY_ATTR_NO_20MHZ: 20 MHz operation is not allowed
+ *      on this channel in current regulatory domain.
+ * @NL80211_FREQUENCY_ATTR_NO_10MHZ: 10 MHz operation is not allowed
+ *      on this channel in current regulatory domain.
  * @NL80211_FREQUENCY_ATTR_MAX: highest frequency attribute number
  *      currently defined
  * @__NL80211_FREQUENCY_ATTR_AFTER_LAST: internal use
@@ -2384,6 +2388,8 @@ enum nl80211_frequency_attr {
         NL80211_FREQUENCY_ATTR_DFS_CAC_TIME,
         NL80211_FREQUENCY_ATTR_INDOOR_ONLY,
         NL80211_FREQUENCY_ATTR_GO_CONCURRENT,
+        NL80211_FREQUENCY_ATTR_NO_20MHZ,
+        NL80211_FREQUENCY_ATTR_NO_10MHZ,
 
         /* keep last */
         __NL80211_FREQUENCY_ATTR_AFTER_LAST,