hostapd: enter DFS state if no available channel is found

Previously hostapd would not stop transmitting when a DFS event was
detected and no available channel to switch to was available.

Disable and re-enable the interface to enter DFS state. This way, TX
does not happen until the kernel notifies hostapd about the NOP
expiring.

Signed-off-by: David Bauer <mail@david-bauer.net>

diff --git a/package/network/services/hostapd/patches/800-dfs-enter-DFS-state-if-no-available-channel-is-found.patch b/package/network/services/hostapd/patches/800-dfs-enter-DFS-state-if-no-available-channel-is-found.patch
new file mode 100644 (file)
index 0000000..e2db99e
--- /dev/null
+++ b/package/network/services/hostapd/patches/800-dfs-enter-DFS-state-if-no-available-channel-is-found.patch
@@ -0,0 +1,37 @@
+From cefc52e6b93731c713f1bba1cb5e7e92105b758b Mon Sep 17 00:00:00 2001
+From: David Bauer <mail@david-bauer.net>
+Date: Fri, 3 Jul 2020 23:00:34 +0200
+Subject: [PATCH] dfs: enter DFS state if no available channel is found
+
+Previously hostapd would not stop transmitting when a DFS event was
+detected and no available channel to switch to was available.
+
+Disable and re-enable the interface to enter DFS state. This way, TX
+does not happen until the kernel notifies hostapd about the NOP
+expiring.
+
+Signed-off-by: David Bauer <mail@david-bauer.net>
+---
+ src/ap/dfs.c | 11 +++++++++--
+ 1 file changed, 9 insertions(+), 2 deletions(-)
+
+--- a/src/ap/dfs.c
++++ b/src/ap/dfs.c
+@@ -1066,8 +1066,15 @@ static int hostapd_dfs_start_channel_swi
+                                                 &oper_centr_freq_seg0_idx,
+                                                 &oper_centr_freq_seg1_idx,
+                                                 &skip_radar);
+-              if (!channel)
+-                      return err;
++              if (!channel) {
++                      /*
++                       * Toggle interface state to enter DFS state
++                       * until NOP is finished.
++                       */
++                      hostapd_disable_iface(iface);
++                      hostapd_enable_iface(iface);
++                      return 0;
++              }
+               if (!skip_radar) {
+                       iface->freq = channel->freq;
+                       iface->conf->channel = channel->chan;