hostapd: ubus: add DFS channels support during CSA

Add options to trigger CSA with DFS channels, without
this patch ubus request was rejected:
ubus call hostapd.wlan0 switch_chan '{"freq":5260,"bcn_count":10}'
Command failed: Operation not supported

Fixes: WIFI-13385

Signed-off-by: Marek Kwaczynski <marek@shasta.cloud>

feeds/wifi-ax/hostapd/patches/x-0006-ubus-csa-add-dfs-support.patch

@@ -0,0 +1,54 @@
+Index: hostapd-2021-02-20-59e9794c/src/ap/ubus.c
+===================================================================
+--- hostapd-2021-02-20-59e9794c.orig/src/ap/ubus.c
++++ hostapd-2021-02-20-59e9794c/src/ap/ubus.c
+@@ -25,6 +25,7 @@
+ #include "airtime_policy.h"
+ #include "hw_features.h"
+ #include "radius_client.h"
++#include "dfs.h"
+
+ static struct ubus_context *ctx;
+ static struct blob_buf b;
+@@ -857,6 +858,7 @@ hostapd_switch_chan(struct ubus_context
+ 	u8 seg0 = 0, seg1 = 0;
+ 	int ret = UBUS_STATUS_OK;
+ 	int i;
++	int dfs_range = 0;
+
+ 	blobmsg_parse(csa_policy, __CSA_MAX, tb, blob_data(msg), blob_len(msg));
+
+@@ -912,6 +914,17 @@ hostapd_switch_chan(struct ubus_context
+ 		break;
+ 	}
+
++	if (css.freq_params.center_freq1)
++		dfs_range += hostapd_is_dfs_overlap(
++			hapd->iface, chwidth, css.freq_params.center_freq1);
++	else
++		dfs_range += hostapd_is_dfs_overlap(
++			hapd->iface, chwidth, css.freq_params.freq);
++
++	if (css.freq_params.center_freq2)
++		dfs_range += hostapd_is_dfs_overlap(
++			hapd->iface, chwidth, css.freq_params.center_freq2);
++
+ 	hostapd_set_freq_params(&css.freq_params, iconf->hw_mode,
+ 				css.freq_params.freq,
+ 				css.freq_params.channel, iconf->enable_edmg,
+@@ -925,6 +938,15 @@ hostapd_switch_chan(struct ubus_context
+ 				mode ? &mode->he_capab[IEEE80211_MODE_AP] :
+ 				NULL);
+
++	if (dfs_range) {
++		/* Perform CAC and switch channel */
++		freq_params = malloc(sizeof(*freq_params));
++		memcpy(freq_params, &css.freq_params, sizeof(*freq_params));
++		eloop_register_timeout(0, 1, switch_chan_fallback_cb,
++				       hapd->iface, freq_params);
++		return 0;
++	}
++
+ 	for (i = 0; i < hapd->iface->num_bss; i++) {
+ 		struct hostapd_data *bss = hapd->iface->bss[i];
+