wifi: mac80211_hwsim: background CAC support

Report background CAC support and add allow
to cancel background CAC and simulate radar.

echo cancel > /sys/kernel/debug/ieee80211/phy2/hwsim/dfs_background_cac
echo radar > /sys/kernel/debug/ieee80211/phy2/hwsim/dfs_background_cac

Signed-off-by: Janusz Dziedzic <janusz.dziedzic@gmail.com>
Link: https://patch.msgid.link/20260206171830.553879-5-janusz.dziedzic@gmail.com
Signed-off-by: Johannes Berg <johannes.berg@intel.com>

2 files changed, 79 insertions, 0 deletions

diff --git a/drivers/net/wireless/virtual/mac80211_hwsim.c b/drivers/net/wireless/virtual/mac80211_hwsim.c
index e89173f91637..d2a43eec4641 100644
--- a/drivers/net/wireless/virtual/mac80211_hwsim.c
+++ b/drivers/net/wireless/virtual/mac80211_hwsim.c
@@ -715,6 +715,7 @@ struct mac80211_hwsim_data {
 	} ps;
 	bool ps_poll_pending;
 	struct dentry *debugfs;
+	struct cfg80211_chan_def radar_background_chandef;
 
 	atomic_t pending_cookie;
 	struct sk_buff_head pending;	/* packets pending */
@@ -936,6 +937,7 @@ static const struct nla_policy hwsim_genl_policy[HWSIM_ATTR_MAX + 1] = {
 	[HWSIM_ATTR_PMSR_RESULT] = NLA_POLICY_NESTED(hwsim_pmsr_peers_result_policy),
 	[HWSIM_ATTR_MULTI_RADIO] = { .type = NLA_FLAG },
 	[HWSIM_ATTR_SUPPORT_NAN_DEVICE] = { .type = NLA_FLAG },
+	[HWSIM_ATTR_SUPPORT_BACKGROUND_RADAR] = { .type = NLA_FLAG },
 };
 
 #if IS_REACHABLE(CONFIG_VIRTIO)
@@ -1164,6 +1166,41 @@ static int hwsim_write_simulate_radar(void *dat, u64 val)
 DEFINE_DEBUGFS_ATTRIBUTE(hwsim_simulate_radar, NULL,
 			 hwsim_write_simulate_radar, "%llu\n");
 
+static ssize_t hwsim_background_cac_write(struct file *file,
+					  const char __user *user_buf,
+					  size_t count, loff_t *ppos)
+{
+	struct mac80211_hwsim_data *data = file->private_data;
+	char buf[8] = {};
+
+	if (count >= sizeof(buf))
+		return -EINVAL;
+
+	if (copy_from_user(buf, user_buf, count))
+		return -EFAULT;
+
+	/* Check if background radar channel is configured */
+	if (!data->radar_background_chandef.chan)
+		return -ENOENT;
+
+	if (sysfs_streq(buf, "radar"))
+		cfg80211_background_radar_event(data->hw->wiphy,
+						&data->radar_background_chandef,
+						GFP_KERNEL);
+	else if (sysfs_streq(buf, "cancel"))
+		cfg80211_background_cac_abort(data->hw->wiphy);
+	else
+		return -EINVAL;
+
+	return count;
+}
+
+static const struct file_operations hwsim_background_cac_ops = {
+	.write = hwsim_background_cac_write,
+	.open = simple_open,
+	.llseek = default_llseek,
+};
+
 static int hwsim_fops_group_read(void *dat, u64 *val)
 {
 	struct mac80211_hwsim_data *data = dat;
@@ -4154,6 +4191,24 @@ static int mac80211_hwsim_change_nan_config(struct ieee80211_hw *hw,
 	return 0;
 }
 
+static int mac80211_hwsim_set_radar_background(struct ieee80211_hw *hw,
+					       struct cfg80211_chan_def *chan)
+{
+	struct mac80211_hwsim_data *data = hw->priv;
+
+	if (!wiphy_ext_feature_isset(hw->wiphy,
+				     NL80211_EXT_FEATURE_RADAR_BACKGROUND))
+		return -EOPNOTSUPP;
+
+	if (chan)
+		data->radar_background_chandef = *chan;
+	else
+		memset(&data->radar_background_chandef, 0,
+		       sizeof(data->radar_background_chandef));
+
+	return 0;
+}
+
 #ifdef CONFIG_MAC80211_DEBUGFS
 #define HWSIM_DEBUGFS_OPS					\
 	.link_add_debugfs = mac80211_hwsim_link_add_debugfs,
@@ -4189,6 +4244,7 @@ static int mac80211_hwsim_change_nan_config(struct ieee80211_hw *hw,
 	.start_nan = mac80211_hwsim_start_nan,                  \
 	.stop_nan = mac80211_hwsim_stop_nan,                    \
 	.nan_change_conf = mac80211_hwsim_change_nan_config,    \
+	.set_radar_background = mac80211_hwsim_set_radar_background, \
 	HWSIM_DEBUGFS_OPS
 
 #define HWSIM_NON_MLO_OPS					\
@@ -4255,6 +4311,7 @@ struct hwsim_new_radio_params {
 	bool mlo;
 	const struct cfg80211_pmsr_capabilities *pmsr_capa;
 	bool nan_device;
+	bool background_radar;
 };
 
 static void hwsim_mcast_config_msg(struct sk_buff *mcast_skb,
@@ -4340,6 +4397,12 @@ static int append_radio_msg(struct sk_buff *skb, int id,
 		if (ret < 0)
 			return ret;
 	}
+
+	if (param->background_radar) {
+		ret = nla_put_flag(skb, HWSIM_ATTR_SUPPORT_BACKGROUND_RADAR);
+		if (ret < 0)
+			return ret;
+	}
 	return 0;
 }
 
@@ -5794,6 +5857,9 @@ static int mac80211_hwsim_new_radio(struct genl_info *info,
 
 	wiphy_ext_feature_set(hw->wiphy,
 			      NL80211_EXT_FEATURE_DFS_CONCURRENT);
+	if (param->background_radar)
+		wiphy_ext_feature_set(hw->wiphy,
+				      NL80211_EXT_FEATURE_RADAR_BACKGROUND);
 
 	if (param->no_vif)
 		ieee80211_hw_set(hw, NO_AUTO_VIF);
@@ -5832,6 +5898,10 @@ static int mac80211_hwsim_new_radio(struct genl_info *info,
 		debugfs_create_file("dfs_simulate_radar", 0222,
 				    data->debugfs,
 				    data, &hwsim_simulate_radar);
+	if (param->background_radar)
+		debugfs_create_file("dfs_background_cac", 0200,
+				    data->debugfs,
+				    data, &hwsim_background_cac_ops);
 
 	if (param->pmsr_capa) {
 		data->pmsr_capa = *param->pmsr_capa;
@@ -5950,6 +6020,9 @@ static int mac80211_hwsim_get_radio(struct sk_buff *skb,
 	param.channels = data->channels;
 	param.hwname = wiphy_name(data->hw->wiphy);
 	param.pmsr_capa = &data->pmsr_capa;
+	param.background_radar =
+		wiphy_ext_feature_isset(data->hw->wiphy,
+					NL80211_EXT_FEATURE_RADAR_BACKGROUND);
 
 	res = append_radio_msg(skb, data->idx, &param);
 	if (res < 0)
@@ -6387,6 +6460,9 @@ static int hwsim_new_radio_nl(struct sk_buff *msg, struct genl_info *info)
 	if (info->attrs[HWSIM_ATTR_MULTI_RADIO])
 		param.multi_radio = true;
 
+	if (info->attrs[HWSIM_ATTR_SUPPORT_BACKGROUND_RADAR])
+		param.background_radar = true;
+
 	if (info->attrs[HWSIM_ATTR_REG_HINT_ALPHA2])
 		param.reg_alpha2 =
 			nla_data(info->attrs[HWSIM_ATTR_REG_HINT_ALPHA2]);
@@ -7165,6 +7241,7 @@ static int __init init_mac80211_hwsim(void)
 		param.p2p_device = support_p2p_device;
 		param.mlo = mlo;
 		param.multi_radio = multi_radio;
+		param.background_radar = true;
 		param.use_chanctx = channels > 1 || mlo || multi_radio;
 		param.iftypes = HWSIM_IFTYPE_SUPPORT_MASK;
 		if (param.p2p_device)
diff --git a/drivers/net/wireless/virtual/mac80211_hwsim.h b/drivers/net/wireless/virtual/mac80211_hwsim.h
index c2d06cf852a5..a022cd5c0f1c 100644
--- a/drivers/net/wireless/virtual/mac80211_hwsim.h
+++ b/drivers/net/wireless/virtual/mac80211_hwsim.h
@@ -161,6 +161,7 @@ enum hwsim_commands {
  *	Adds one radio for each band. Number of supported channels will be set for
  *	each radio instead of for the wiphy.
  * @HWSIM_ATTR_SUPPORT_NAN_DEVICE: support NAN Device virtual interface (flag)
+ * @HWSIM_ATTR_SUPPORT_BACKGROUND_RADAR: background radar/CAC support (flag)
  * @__HWSIM_ATTR_MAX: enum limit
  */
 enum hwsim_attrs {
@@ -195,6 +196,7 @@ enum hwsim_attrs {
 	HWSIM_ATTR_PMSR_RESULT,
 	HWSIM_ATTR_MULTI_RADIO,
 	HWSIM_ATTR_SUPPORT_NAN_DEVICE,
+	HWSIM_ATTR_SUPPORT_BACKGROUND_RADAR,
 	__HWSIM_ATTR_MAX,
 };
 #define HWSIM_ATTR_MAX (__HWSIM_ATTR_MAX - 1)