[librecmc/librecmc.git] /

From: Felix Fietkau <nbd@nbd.name>
Date: Thu, 14 Sep 2023 13:17:16 +0200
Subject: [PATCH] cfg80211: allow grace period for DFS available after beacon
 shutdown

Fixes reconfiguring an AP on a DFS channel in non-ETSI regdomain

Fixes: b35a51c7dd25 ("cfg80211: Make pre-CAC results valid only for ETSI domain")
Signed-off-by: Felix Fietkau <nbd@nbd.name>
---

--- a/include/net/cfg80211.h
+++ b/include/net/cfg80211.h
@@ -175,6 +175,8 @@ enum ieee80211_channel_flags {
  * @dfs_state: current state of this channel. Only relevant if radar is required
  *     on this channel.
  * @dfs_state_entered: timestamp (jiffies) when the dfs state was entered.
+ * @dfs_state_last_available: timestamp (jiffies) of the last time when the
+ *     channel was available.
  * @dfs_cac_ms: DFS CAC time in milliseconds, this is valid for DFS channels.
  */
 struct ieee80211_channel {
@@ -191,6 +193,7 @@ struct ieee80211_channel {
        int orig_mag, orig_mpwr;
        enum nl80211_dfs_state dfs_state;
        unsigned long dfs_state_entered;
+       unsigned long dfs_state_last_available;
        unsigned int dfs_cac_ms;
 };
 
--- a/net/wireless/ap.c
+++ b/net/wireless/ap.c
@@ -30,6 +30,9 @@ static int ___cfg80211_stop_ap(struct cf
        if (!wdev->links[link_id].ap.beacon_interval)
                return -ENOENT;
 
+       cfg80211_update_last_available(wdev->wiphy,
+                                      &wdev->links[link_id].ap.chandef);
+
        err = rdev_stop_ap(rdev, dev, link_id);
        if (!err) {
                wdev->conn_owner_nlportid = 0;
@@ -41,9 +44,6 @@ static int ___cfg80211_stop_ap(struct cf
                if (notify)
                        nl80211_send_ap_stopped(wdev);
 
-               /* Should we apply the grace period during beaconing interface
-                * shutdown also?
-                */
                cfg80211_sched_dfs_chan_update(rdev);
        }
 
--- a/net/wireless/chan.c
+++ b/net/wireless/chan.c
@@ -461,6 +461,8 @@ static void cfg80211_set_chans_dfs_state
 
                c->dfs_state = dfs_state;
                c->dfs_state_entered = jiffies;
+               if (dfs_state == NL80211_DFS_AVAILABLE)
+                       c->dfs_state_last_available = jiffies;
        }
 }
 
@@ -873,6 +875,49 @@ static bool cfg80211_get_chans_dfs_avail
        return true;
 }
 
+static void
+__cfg80211_update_last_available(struct wiphy *wiphy,
+                                        u32 center_freq,
+                                        u32 bandwidth)
+{
+       struct ieee80211_channel *c;
+       u32 freq, start_freq, end_freq;
+
+       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 += MHZ_TO_KHZ(20)) {
+               c = ieee80211_get_channel_khz(wiphy, freq);
+               if (!c)
+                       return;
+
+               c->dfs_state_last_available = jiffies;
+       }
+}
+
+void cfg80211_update_last_available(struct wiphy *wiphy,
+                                   const struct cfg80211_chan_def *chandef)
+{
+       int width;
+
+       width = cfg80211_chandef_get_width(chandef);
+       if (width < 0)
+               return;
+
+       __cfg80211_update_last_available(wiphy, MHZ_TO_KHZ(chandef->center_freq1),
+                                                width);
+       if (chandef->width != NL80211_CHAN_WIDTH_80P80)
+           return;
+
+       __cfg80211_update_last_available(wiphy, MHZ_TO_KHZ(chandef->center_freq2),
+                                                width);
+}
+
 static bool cfg80211_chandef_dfs_available(struct wiphy *wiphy,
                                const struct cfg80211_chan_def *chandef)
 {
--- a/net/wireless/core.h
+++ b/net/wireless/core.h
@@ -477,6 +477,8 @@ void cfg80211_set_dfs_state(struct wiphy
                            enum nl80211_dfs_state dfs_state);
 
 void cfg80211_dfs_channels_update_work(struct work_struct *work);
+void cfg80211_update_last_available(struct wiphy *wiphy,
+                                   const struct cfg80211_chan_def *chandef);
 
 unsigned int
 cfg80211_chandef_dfs_cac_time(struct wiphy *wiphy,
--- a/net/wireless/mlme.c
+++ b/net/wireless/mlme.c
@@ -891,6 +891,8 @@ void cfg80211_dfs_channels_update_work(s
                        if (c->dfs_state == NL80211_DFS_UNAVAILABLE) {
                                time_dfs_update = IEEE80211_DFS_MIN_NOP_TIME_MS;
                                radar_event = NL80211_RADAR_NOP_FINISHED;
+                               timeout = c->dfs_state_entered +
+                                         msecs_to_jiffies(time_dfs_update);
                        } else {
                                if (regulatory_pre_cac_allowed(wiphy) ||
                                    cfg80211_any_wiphy_oper_chan(wiphy, c))
@@ -898,11 +900,10 @@ void cfg80211_dfs_channels_update_work(s
 
                                time_dfs_update = REG_PRE_CAC_EXPIRY_GRACE_MS;
                                radar_event = NL80211_RADAR_PRE_CAC_EXPIRED;
+                               timeout = c->dfs_state_last_available +
+                                         msecs_to_jiffies(time_dfs_update);
                        }
 
-                       timeout = c->dfs_state_entered +
-                                 msecs_to_jiffies(time_dfs_update);
-
                        if (time_after_eq(jiffies, timeout)) {
                                c->dfs_state = NL80211_DFS_USABLE;
                                c->dfs_state_entered = jiffies;