catspeed-cc/openwrt
2
1
Fork 0
Code Issues Pull Requests Activity

mac80211: fix AP+STA on DFS channels

Browse Source 
Allow skipping CAC on AP bringup if the STA is connected already.

Signed-off-by: Felix Fietkau <nbd@nbd.name>
This commit is contained in:
Felix Fietkau 2026-02-01 18:31:36 +00:00
parent 8e3de10b44
commit 29bb3f6b96
1 changed files with 99 additions and 0 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

99
package/kernel/mac80211/patches/subsys/311-cfg80211-allow-concurrent-AP-operation-on-DFS-channe.patch Normal file
View File

@ -0,0 +1,99 @@
From: Felix Fietkau <nbd@nbd.name>
Date: Sun, 1 Feb 2026 18:29:51 +0000
Subject: [PATCH] cfg80211: allow concurrent AP operation on DFS channels with
connected STA
When a station interface is connected to an AP on a DFS channel, the
station is already performing radar detection as required by the
regulatory domain. Allow starting an AP on the same DFS channel by
treating CAC as immediately complete when a concurrent station covers
all required DFS subchannels.
This enables scenarios where a device acts as both a client and an
access point on the same DFS channel without requiring a separate CAC
period, since the connected station already provides the required radar
monitoring.
The implementation checks if all DFS subchannels in the requested
channel definition are covered by a connected station's operating
channel. If so, the channel state is set to available and CAC completion
is signaled immediately. If any DFS subchannel is not covered by the
station (e.g., AP requests wider bandwidth than the station connection),
normal CAC is required.
After CAC completes (immediately or normally), mac80211 automatically
enables radar detection on the AP interface, ensuring continued
compliance with DFS requirements even if the station disconnects.
Signed-off-by: Felix Fietkau <nbd@nbd.name>
---
--- a/net/wireless/chan.c
+++ b/net/wireless/chan.c
@@ -717,6 +717,44 @@ static bool cfg80211_dfs_permissive_chan
return false;
}
+static bool cfg80211_dfs_sta_present(struct wiphy *wiphy,
+ struct ieee80211_channel *chan)
+{
+ struct cfg80211_registered_device *rdev = wiphy_to_rdev(wiphy);
+ struct wireless_dev *wdev;
+
+ lockdep_assert_held(&rdev->wiphy.mtx);
+
+ if (!(chan->flags & IEEE80211_CHAN_RADAR))
+ return false;
+
+ list_for_each_entry(wdev, &rdev->wiphy.wdev_list, list) {
+ if (cfg80211_dfs_permissive_check_wdev(rdev, NL80211_IFTYPE_AP,
+ wdev, chan))
+ return true;
+ }
+
+ return false;
+}
+
+void cfg80211_set_dfs_concurrent(struct wiphy *wiphy,
+ const struct cfg80211_chan_def *chandef)
+{
+ struct ieee80211_channel *c;
+
+ for_each_subchan(chandef, freq, cf) {
+ c = ieee80211_get_channel_khz(wiphy, freq);
+ if (!c)
+ return;
+
+ if ((c->flags & IEEE80211_CHAN_RADAR) &&
+ !cfg80211_dfs_sta_present(wiphy, c))
+ return;
+ }
+
+ cfg80211_set_dfs_state(wiphy, chandef, NL80211_DFS_AVAILABLE);
+}
+
static int cfg80211_get_chans_dfs_required(struct wiphy *wiphy,
const struct cfg80211_chan_def *chandef,
enum nl80211_iftype iftype)
--- a/net/wireless/core.h
+++ b/net/wireless/core.h
@@ -479,6 +479,8 @@ extern struct work_struct cfg80211_disco
void cfg80211_set_dfs_state(struct wiphy *wiphy,
const struct cfg80211_chan_def *chandef,
enum nl80211_dfs_state dfs_state);
+void cfg80211_set_dfs_concurrent(struct wiphy *wiphy,
+ const struct cfg80211_chan_def *chandef);
void cfg80211_dfs_channels_update_work(struct work_struct *work);
void cfg80211_update_last_available(struct wiphy *wiphy,
--- a/net/wireless/nl80211.c
+++ b/net/wireless/nl80211.c
@@ -6741,6 +6741,8 @@ static int nl80211_start_ap(struct sk_bu
goto out;
}
+ cfg80211_set_dfs_concurrent(&rdev->wiphy, &params->chandef);
+
beacon_check.iftype = wdev->iftype;
beacon_check.relax = true;
beacon_check.reg_power =