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>

diff --git a/include/net/cfg80211.h b/include/net/cfg80211.h
index 3dd2cb465540c66b9e0d360a1657ea8d98abca21..c98cf08538b9651958323ce1a828f9049ff5b15a 100644 (file)
--- 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 513bfd7b2e5f72ff7e5f6395271ab045ad02109c..0592032ff160fe27ff95fa70682201fa991559f4 100644 (file)
--- 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,

diff --git a/net/wireless/chan.c b/net/wireless/chan.c
index 2adf7b2eccbca19d84db204c480fb7d21ba15e6d..84d686e2dbd04a0402a652995ec468ba6df06795 100644 (file)
--- a/net/wireless/chan.c
+++ b/net/wireless/chan.c
@@ -616,12 +616,14 @@ bool cfg80211_chandef_usable(struct wiphy *wiphy,
                width = 5;
                break;
        case NL80211_CHAN_WIDTH_10:
+               prohibited_flags |= IEEE80211_CHAN_NO_10MHZ;
                width = 10;
                break;
        case NL80211_CHAN_WIDTH_20:
                if (!ht_cap->ht_supported)
                        return false;
        case NL80211_CHAN_WIDTH_20_NOHT:
+               prohibited_flags |= IEEE80211_CHAN_NO_20MHZ;
                width = 20;
                break;
        case NL80211_CHAN_WIDTH_40:

diff --git a/net/wireless/nl80211.c b/net/wireless/nl80211.c
index fce423a4e96afcb0f9645575071c3407afeeb096..ca75f60041d2156ba4b61cb7c05bd0b85883e525 100644 (file)
--- a/net/wireless/nl80211.c
+++ b/net/wireless/nl80211.c
@@ -567,6 +567,13 @@ static int nl80211_msg_put_channel(struct sk_buff *msg,
                                   struct ieee80211_channel *chan,
                                   bool large)
 {
+       /* Some channels must be completely excluded from the
+        * list to protect old user-space tools from breaking
+        */
+       if (!large && chan->flags &
+           (IEEE80211_CHAN_NO_10MHZ | IEEE80211_CHAN_NO_20MHZ))
+               return 0;
+
        if (nla_put_u32(msg, NL80211_FREQUENCY_ATTR_FREQ,
                        chan->center_freq))
                goto nla_put_failure;
@@ -620,6 +627,12 @@ static int nl80211_msg_put_channel(struct sk_buff *msg,
                if ((chan->flags & IEEE80211_CHAN_GO_CONCURRENT) &&
                    nla_put_flag(msg, NL80211_FREQUENCY_ATTR_GO_CONCURRENT))
                        goto nla_put_failure;
+               if ((chan->flags & IEEE80211_CHAN_NO_20MHZ) &&
+                   nla_put_flag(msg, NL80211_FREQUENCY_ATTR_NO_20MHZ))
+                       goto nla_put_failure;
+               if ((chan->flags & IEEE80211_CHAN_NO_10MHZ) &&
+                   nla_put_flag(msg, NL80211_FREQUENCY_ATTR_NO_10MHZ))
+                       goto nla_put_failure;
        }
 
        if (nla_put_u32(msg, NL80211_FREQUENCY_ATTR_MAX_TX_POWER,