cfg80211: allow beaconing after DFS CAC

Allow beconing after we pass Channel Availability Check (CAC).
Allow non-DFS and DFS channels mix. All DFS channels have to
be in NL80211_DFS_AVAILABLE state (pass CAC).

Signed-off-by: Janusz Dziedzic <janusz.dziedzic@tieto.com>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>

1 files changed, 74 insertions, 11 deletions

diff --git a/net/wireless/chan.c b/net/wireless/chan.c
index 3b6daf8b47d9..78559b5bbd1f 100644
--- a/net/wireless/chan.c
+++ b/net/wireless/chan.c
@@ -425,9 +425,9 @@ bool cfg80211_chandef_dfs_usable(struct wiphy *wiphy,
 }
 
 
-static bool cfg80211_secondary_chans_ok(struct wiphy *wiphy,
-                                        u32 center_freq, u32 bandwidth,
-                                        u32 prohibited_flags)
+static bool cfg80211_get_chans_dfs_available(struct wiphy *wiphy,
+                                             u32 center_freq,
+                                             u32 bandwidth)
 {
         struct ieee80211_channel *c;
         u32 freq, start_freq, end_freq;
@@ -435,18 +435,75 @@ static bool cfg80211_secondary_chans_ok(struct wiphy *wiphy,
         start_freq = cfg80211_get_start_freq(center_freq, bandwidth);
         end_freq = cfg80211_get_end_freq(center_freq, bandwidth);
 
+        /*
+         * Check entire range of channels for the bandwidth.
+         * If any channel in between is disabled or has not
+         * had gone through CAC return false
+         */
         for (freq = start_freq; freq <= end_freq; freq += 20) {
                 c = ieee80211_get_channel(wiphy, freq);
                 if (!c)
                         return false;
 
-                /* check for radar flags */
-                if ((prohibited_flags & c->flags & IEEE80211_CHAN_RADAR) &&
+                if (c->flags & IEEE80211_CHAN_DISABLED)
+                        return false;
+
+                if ((c->flags & IEEE80211_CHAN_RADAR)  &&
                     (c->dfs_state != NL80211_DFS_AVAILABLE))
                         return false;
+        }
+
+        return true;
+}
+
+static bool cfg80211_chandef_dfs_available(struct wiphy *wiphy,
+                                const struct cfg80211_chan_def *chandef)
+{
+        int width;
+        int r;
+
+        if (WARN_ON(!cfg80211_chandef_valid(chandef)))
+                return false;
+
+        width = cfg80211_chandef_get_width(chandef);
+        if (width < 0)
+                return false;
+
+        r = cfg80211_get_chans_dfs_available(wiphy, chandef->center_freq1,
+                                             width);
+
+        /* If any of channels unavailable for cf1 just return */
+        if (!r)
+                return r;
+
+        switch (chandef->width) {
+        case NL80211_CHAN_WIDTH_80P80:
+                WARN_ON(!chandef->center_freq2);
+                r = cfg80211_get_chans_dfs_available(wiphy,
+                                                     chandef->center_freq2,
+                                                     width);
+        default:
+                WARN_ON(chandef->center_freq2);
+                break;
+        }
+
+        return r;
+}
+
+
+static bool cfg80211_secondary_chans_ok(struct wiphy *wiphy,
+                                        u32 center_freq, u32 bandwidth,
+                                        u32 prohibited_flags)
+{
+        struct ieee80211_channel *c;
+        u32 freq, start_freq, end_freq;
 
-                /* check for the other flags */
-                if (c->flags & prohibited_flags & ~IEEE80211_CHAN_RADAR)
+        start_freq = cfg80211_get_start_freq(center_freq, bandwidth);
+        end_freq = cfg80211_get_end_freq(center_freq, bandwidth);
+
+        for (freq = start_freq; freq <= end_freq; freq += 20) {
+                c = ieee80211_get_channel(wiphy, freq);
+                if (!c || c->flags & prohibited_flags)
                         return false;
         }
 
@@ -552,13 +609,19 @@ bool cfg80211_reg_can_beacon(struct wiphy *wiphy,
                              struct cfg80211_chan_def *chandef)
 {
         bool res;
+        u32 prohibited_flags = IEEE80211_CHAN_DISABLED |
+                               IEEE80211_CHAN_NO_IR |
+                               IEEE80211_CHAN_RADAR;
 
         trace_cfg80211_reg_can_beacon(wiphy, chandef);
 
-        res = cfg80211_chandef_usable(wiphy, chandef,
-                                      IEEE80211_CHAN_DISABLED |
-                                      IEEE80211_CHAN_NO_IR |
-                                      IEEE80211_CHAN_RADAR);
+        if (cfg80211_chandef_dfs_required(wiphy, chandef) > 0 &&
+            cfg80211_chandef_dfs_available(wiphy, chandef)) {
+                /* We can skip IEEE80211_CHAN_NO_IR if chandef dfs available */
+                prohibited_flags = IEEE80211_CHAN_DISABLED;
+        }
+
+        res = cfg80211_chandef_usable(wiphy, chandef, prohibited_flags);
 
         trace_cfg80211_return_bool(res);
         return res;