cfg80211: DFS check chandef usable before CAC

Check chandef we get in CAC request is usable for CAC.
All channels have to be DFS channels. Allow DFS_USABLE
and DFS_AVAILABLE channels mix. At least one channel
has to be DFS_USABLE (require CAC).

Signed-off-by: Janusz Dziedzic <janusz.dziedzic@tieto.com>
Reviewed-by: Luis R. Rodriguez <mcgrof@do-not-panic.com>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>

diff --git a/net/wireless/chan.c b/net/wireless/chan.c
index 1d25a46..96c9780 100644 (file)
--- a/net/wireless/chan.c
+++ b/net/wireless/chan.c
@@ -351,6 +351,80 @@ int cfg80211_chandef_dfs_required(struct wiphy *wiphy,
 }
 EXPORT_SYMBOL(cfg80211_chandef_dfs_required);
 
+static int cfg80211_get_chans_dfs_usable(struct wiphy *wiphy,
+                                        u32 center_freq,
+                                        u32 bandwidth)
+{
+       struct ieee80211_channel *c;
+       u32 freq, start_freq, end_freq;
+       int count = 0;
+
+       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.
+        * Check all channels are DFS channels (DFS_USABLE or
+        * DFS_AVAILABLE). Return number of usable channels
+        * (require CAC). Allow DFS and non-DFS channel mix.
+        */
+       for (freq = start_freq; freq <= end_freq; freq += 20) {
+               c = ieee80211_get_channel(wiphy, freq);
+               if (!c)
+                       return -EINVAL;
+
+               if (c->flags & IEEE80211_CHAN_DISABLED)
+                       return -EINVAL;
+
+               if (c->flags & IEEE80211_CHAN_RADAR) {
+                       if (c->dfs_state == NL80211_DFS_UNAVAILABLE)
+                               return -EINVAL;
+
+                       if (c->dfs_state == NL80211_DFS_USABLE)
+                               count++;
+               }
+       }
+
+       return count;
+}
+
+bool cfg80211_chandef_dfs_usable(struct wiphy *wiphy,
+                                const struct cfg80211_chan_def *chandef)
+{
+       int width;
+       int r1, r2 = 0;
+
+       if (WARN_ON(!cfg80211_chandef_valid(chandef)))
+               return false;
+
+       width = cfg80211_chandef_get_width(chandef);
+       if (width < 0)
+               return false;
+
+       r1 = cfg80211_get_chans_dfs_usable(wiphy, chandef->center_freq1,
+                                         width);
+
+       if (r1 < 0)
+               return false;
+
+       switch (chandef->width) {
+       case NL80211_CHAN_WIDTH_80P80:
+               WARN_ON(!chandef->center_freq2);
+               r2 = cfg80211_get_chans_dfs_usable(wiphy,
+                                                  chandef->center_freq2,
+                                                  width);
+               if (r2 < 0)
+                       return false;
+               break;
+       default:
+               WARN_ON(chandef->center_freq2);
+               break;
+       }
+
+       return (r1 + r2 > 0);
+}
+
+
 static bool cfg80211_secondary_chans_ok(struct wiphy *wiphy,
                                        u32 center_freq, u32 bandwidth,
                                        u32 prohibited_flags)

diff --git a/net/wireless/core.h b/net/wireless/core.h
index eb0f7a3..2888867 100644 (file)
--- a/net/wireless/core.h
+++ b/net/wireless/core.h
@@ -382,6 +382,19 @@ int cfg80211_can_use_iftype_chan(struct cfg80211_registered_device *rdev,
                                 enum cfg80211_chan_mode chanmode,
                                 u8 radar_detect);
 
+/**
+ * cfg80211_chandef_dfs_usable - checks if chandef is DFS usable
+ * @wiphy: the wiphy to validate against
+ * @chandef: the channel definition to check
+ *
+ * Checks if chandef is usable and we can/need start CAC on such channel.
+ *
+ * Return: Return true if all channels available and at least
+ *        one channel require CAC (NL80211_DFS_USABLE)
+ */
+bool cfg80211_chandef_dfs_usable(struct wiphy *wiphy,
+                                const struct cfg80211_chan_def *chandef);
+
 void cfg80211_set_dfs_state(struct wiphy *wiphy,
                            const struct cfg80211_chan_def *chandef,
                            enum nl80211_dfs_state dfs_state);

diff --git a/net/wireless/nl80211.c b/net/wireless/nl80211.c
index 41af3a0..e2bb427 100644 (file)
--- a/net/wireless/nl80211.c
+++ b/net/wireless/nl80211.c
@@ -5651,7 +5651,7 @@ static int nl80211_start_radar_detection(struct sk_buff *skb,
        if (err == 0)
                return -EINVAL;
 
-       if (chandef.chan->dfs_state != NL80211_DFS_USABLE)
+       if (!cfg80211_chandef_dfs_usable(wdev->wiphy, &chandef))
                return -EINVAL;
 
        if (!rdev->ops->start_radar_detection)