wifi: cfg80211: add regulatory flag to allow VLP AP operation

Add a regulatory flag to allow VLP AP operation even on
channels otherwise marked NO_IR, which may be possible
in some regulatory domains/countries.

Note that this requires checking also when the beacon is
changed, since that may change the regulatory power type.
Reviewed-by: Miriam Rachel Korenblit <miriam.rachel.korenblit@intel.com>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Link: https://msgid.link/20240523120945.63792ce19790.Ie2a02750d283b78fbf3c686b10565fb0388889e2@changeidSigned-off-by: Johannes Berg <johannes.berg@intel.com>

include/net/cfg80211.h

@@ -125,6 +125,8 @@ struct wiphy;
  * @IEEE80211_CHAN_CAN_MONITOR: This channel can be used for monitor
  *	mode even in the presence of other (regulatory) restrictions,
  *	even if it is otherwise disabled.
+ * @IEEE80211_CHAN_ALLOW_6GHZ_VLP_AP: Allow using this channel for AP operation
+ *	with very low power (VLP), even if otherwise set to NO_IR.
  */
 enum ieee80211_channel_flags {
 	IEEE80211_CHAN_DISABLED			= BIT(0),
@@ -152,6 +154,7 @@ enum ieee80211_channel_flags {
 	IEEE80211_CHAN_NO_6GHZ_VLP_CLIENT	= BIT(22),
 	IEEE80211_CHAN_NO_6GHZ_AFC_CLIENT	= BIT(23),
 	IEEE80211_CHAN_CAN_MONITOR		= BIT(24),
+	IEEE80211_CHAN_ALLOW_6GHZ_VLP_AP	= BIT(25),
 };
 
 #define IEEE80211_CHAN_NO_HT40 \
@@ -8806,9 +8809,12 @@ static inline void cfg80211_report_obss_beacon(struct wiphy *wiphy,
  * @relax: allow IR-relaxation conditions to apply (e.g. another
  *	interface connected already on the same channel)
  *	NOTE: If this is set, wiphy mutex must be held.
+ * @reg_power: &enum ieee80211_ap_reg_power value indicating the
+ *	advertised/used 6 GHz regulatory power setting
  */
 struct cfg80211_beaconing_check_config {
 	enum nl80211_iftype iftype;
+	enum ieee80211_ap_reg_power reg_power;
 	bool relax;
 };
 

include/uapi/linux/nl80211.h

@@ -4277,6 +4277,8 @@ enum nl80211_wmm_rule {
  * @NL80211_FREQUENCY_ATTR_CAN_MONITOR: This channel can be used in monitor
  *	mode despite other (regulatory) restrictions, even if the channel is
  *	otherwise completely disabled.
+ * @NL80211_FREQUENCY_ATTR_ALLOW_6GHZ_VLP_AP: This channel can be used for a
+ *	very low power (VLP) AP, despite being NO_IR.
  * @NL80211_FREQUENCY_ATTR_MAX: highest frequency attribute number
  *	currently defined
  * @__NL80211_FREQUENCY_ATTR_AFTER_LAST: internal use
@@ -4320,6 +4322,7 @@ enum nl80211_frequency_attr {
 	NL80211_FREQUENCY_ATTR_NO_6GHZ_VLP_CLIENT,
 	NL80211_FREQUENCY_ATTR_NO_6GHZ_AFC_CLIENT,
 	NL80211_FREQUENCY_ATTR_CAN_MONITOR,
+	NL80211_FREQUENCY_ATTR_ALLOW_6GHZ_VLP_AP,
 
 	/* keep last */
 	__NL80211_FREQUENCY_ATTR_AFTER_LAST,
@@ -4529,6 +4532,8 @@ enum nl80211_sched_scan_match_attr {
  *	Should be used together with %NL80211_RRF_DFS only.
  * @NL80211_RRF_NO_6GHZ_VLP_CLIENT: Client connection to VLP AP not allowed
  * @NL80211_RRF_NO_6GHZ_AFC_CLIENT: Client connection to AFC AP not allowed
+ * @NL80211_RRF_ALLOW_6GHZ_VLP_AP: Very low power (VLP) AP can be permitted
+ *	despite NO_IR configuration.
  */
 enum nl80211_reg_rule_flags {
 	NL80211_RRF_NO_OFDM		= 1<<0,
@@ -4553,6 +4558,7 @@ enum nl80211_reg_rule_flags {
 	NL80211_RRF_DFS_CONCURRENT	= 1<<21,
 	NL80211_RRF_NO_6GHZ_VLP_CLIENT	= 1<<22,
 	NL80211_RRF_NO_6GHZ_AFC_CLIENT	= 1<<23,
+	NL80211_RRF_ALLOW_6GHZ_VLP_AP	= 1<<24,
 };
 
 #define NL80211_RRF_PASSIVE_SCAN	NL80211_RRF_NO_IR

net/wireless/chan.c

@@ -1523,28 +1523,38 @@ static bool cfg80211_ir_permissive_chan(struct wiphy *wiphy,
 static bool _cfg80211_reg_can_beacon(struct wiphy *wiphy,
 				     struct cfg80211_chan_def *chandef,
 				     enum nl80211_iftype iftype,
-				     bool check_no_ir)
+				     u32 prohibited_flags,
+				     u32 permitting_flags)
 {
-	bool res;
-	u32 prohibited_flags = IEEE80211_CHAN_DISABLED;
+	bool res, check_radar;
 	int dfs_required;
 
-	trace_cfg80211_reg_can_beacon(wiphy, chandef, iftype, check_no_ir);
+	trace_cfg80211_reg_can_beacon(wiphy, chandef, iftype,
+				      prohibited_flags,
+				      permitting_flags);
 
-	if (check_no_ir)
-		prohibited_flags |= IEEE80211_CHAN_NO_IR;
+	if (!_cfg80211_chandef_usable(wiphy, chandef,
+				      IEEE80211_CHAN_DISABLED, 0))
+		return false;
 
 	dfs_required = cfg80211_chandef_dfs_required(wiphy, chandef, iftype);
-	if (dfs_required != 0)
-		prohibited_flags |= IEEE80211_CHAN_RADAR;
+	check_radar = dfs_required != 0;
 
 	if (dfs_required > 0 &&
 	    cfg80211_chandef_dfs_available(wiphy, chandef)) {
 		/* We can skip IEEE80211_CHAN_NO_IR if chandef dfs available */
-		prohibited_flags = IEEE80211_CHAN_DISABLED;
+		prohibited_flags &= ~IEEE80211_CHAN_NO_IR;
+		check_radar = false;
 	}
 
-	res = _cfg80211_chandef_usable(wiphy, chandef, prohibited_flags, 0);
+	if (check_radar &&
+	    !_cfg80211_chandef_usable(wiphy, chandef,
+				      IEEE80211_CHAN_RADAR, 0))
+		return false;
+
+	res = _cfg80211_chandef_usable(wiphy, chandef,
+				       prohibited_flags,
+				       permitting_flags);
 
 	trace_cfg80211_return_bool(res);
 	return res;
@@ -1555,6 +1565,7 @@ bool cfg80211_reg_check_beaconing(struct wiphy *wiphy,
 				  struct cfg80211_beaconing_check_config *cfg)
 {
 	struct cfg80211_registered_device *rdev = wiphy_to_rdev(wiphy);
+	u32 permitting_flags = 0;
 	bool check_no_ir = true;
 
 	/*
@@ -1569,8 +1580,12 @@ bool cfg80211_reg_check_beaconing(struct wiphy *wiphy,
 							   chandef->chan);
 	}
 
+	if (cfg->reg_power == IEEE80211_REG_VLP_AP)
+		permitting_flags |= IEEE80211_CHAN_ALLOW_6GHZ_VLP_AP;
+
 	return _cfg80211_reg_can_beacon(wiphy, chandef, cfg->iftype,
-					check_no_ir);
+					check_no_ir ? IEEE80211_CHAN_NO_IR : 0,
+					permitting_flags);
 }
 EXPORT_SYMBOL(cfg80211_reg_check_beaconing);
 

net/wireless/nl80211.c

@@ -1207,6 +1207,9 @@ static int nl80211_msg_put_channel(struct sk_buff *msg, struct wiphy *wiphy,
 		if ((chan->flags & IEEE80211_CHAN_CAN_MONITOR) &&
 		    nla_put_flag(msg, NL80211_FREQUENCY_ATTR_CAN_MONITOR))
 			goto nla_put_failure;
+		if ((chan->flags & IEEE80211_CHAN_ALLOW_6GHZ_VLP_AP) &&
+		    nla_put_flag(msg, NL80211_FREQUENCY_ATTR_ALLOW_6GHZ_VLP_AP))
+			goto nla_put_failure;
 	}
 
 	if (nla_put_u32(msg, NL80211_FREQUENCY_ATTR_MAX_TX_POWER,
@@ -5954,6 +5957,7 @@ static int nl80211_validate_ap_phy_operation(struct cfg80211_ap_settings *params
 static int nl80211_start_ap(struct sk_buff *skb, struct genl_info *info)
 {
 	struct cfg80211_registered_device *rdev = info->user_ptr[0];
+	struct cfg80211_beaconing_check_config beacon_check = {};
 	unsigned int link_id = nl80211_link_id(info->attrs);
 	struct net_device *dev = info->user_ptr[1];
 	struct wireless_dev *wdev = dev->ieee80211_ptr;
@@ -6103,8 +6107,13 @@ static int nl80211_start_ap(struct sk_buff *skb, struct genl_info *info)
 		goto out;
 	}
 
-	if (!cfg80211_reg_can_beacon_relax(&rdev->wiphy, &params->chandef,
-					   wdev->iftype)) {
+	beacon_check.iftype = wdev->iftype;
+	beacon_check.relax = true;
+	beacon_check.reg_power =
+		cfg80211_get_6ghz_power_type(params->beacon.tail,
+					     params->beacon.tail_len);
+	if (!cfg80211_reg_check_beaconing(&rdev->wiphy, &params->chandef,
+					  &beacon_check)) {
 		err = -EINVAL;
 		goto out;
 	}
@@ -6261,6 +6270,7 @@ static int nl80211_start_ap(struct sk_buff *skb, struct genl_info *info)
 static int nl80211_set_beacon(struct sk_buff *skb, struct genl_info *info)
 {
 	struct cfg80211_registered_device *rdev = info->user_ptr[0];
+	struct cfg80211_beaconing_check_config beacon_check = {};
 	unsigned int link_id = nl80211_link_id(info->attrs);
 	struct net_device *dev = info->user_ptr[1];
 	struct wireless_dev *wdev = dev->ieee80211_ptr;
@@ -6287,6 +6297,19 @@ static int nl80211_set_beacon(struct sk_buff *skb, struct genl_info *info)
 	if (err)
 		goto out;
 
+	/* recheck beaconing is permitted with possibly changed power type */
+	beacon_check.iftype = wdev->iftype;
+	beacon_check.relax = true;
+	beacon_check.reg_power =
+		cfg80211_get_6ghz_power_type(params->beacon.tail,
+					     params->beacon.tail_len);
+	if (!cfg80211_reg_check_beaconing(&rdev->wiphy,
+					  &wdev->links[link_id].ap.chandef,
+					  &beacon_check)) {
+		err = -EINVAL;
+		goto out;
+	}
+
 	attr = info->attrs[NL80211_ATTR_FILS_DISCOVERY];
 	if (attr) {
 		err = nl80211_parse_fils_discovery(rdev, attr,

net/wireless/reg.c

@@ -1600,6 +1600,8 @@ static u32 map_regdom_flags(u32 rd_flags)
 		channel_flags |= IEEE80211_CHAN_NO_6GHZ_AFC_CLIENT;
 	if (rd_flags & NL80211_RRF_PSD)
 		channel_flags |= IEEE80211_CHAN_PSD;
+	if (rd_flags & NL80211_RRF_ALLOW_6GHZ_VLP_AP)
+		channel_flags |= IEEE80211_CHAN_ALLOW_6GHZ_VLP_AP;
 	return channel_flags;
 }
 

net/wireless/trace.h

@@ -3389,23 +3389,26 @@ TRACE_EVENT(cfg80211_cqm_rssi_notify,
 
 TRACE_EVENT(cfg80211_reg_can_beacon,
 	TP_PROTO(struct wiphy *wiphy, struct cfg80211_chan_def *chandef,
-		 enum nl80211_iftype iftype, bool check_no_ir),
-	TP_ARGS(wiphy, chandef, iftype, check_no_ir),
+		 enum nl80211_iftype iftype, u32 prohibited_flags,
+		 u32 permitting_flags),
+	TP_ARGS(wiphy, chandef, iftype, prohibited_flags, permitting_flags),
 	TP_STRUCT__entry(
 		WIPHY_ENTRY
 		CHAN_DEF_ENTRY
 		__field(enum nl80211_iftype, iftype)
-		__field(bool, check_no_ir)
+		__field(u32, prohibited_flags)
+		__field(u32, permitting_flags)
 	),
 	TP_fast_assign(
 		WIPHY_ASSIGN;
 		CHAN_DEF_ASSIGN(chandef);
 		__entry->iftype = iftype;
-		__entry->check_no_ir = check_no_ir;
+		__entry->prohibited_flags = prohibited_flags;
+		__entry->permitting_flags = permitting_flags;
 	),
-	TP_printk(WIPHY_PR_FMT ", " CHAN_DEF_PR_FMT ", iftype=%d check_no_ir=%s",
+	TP_printk(WIPHY_PR_FMT ", " CHAN_DEF_PR_FMT ", iftype=%d prohibited_flags=0x%x permitting_flags=0x%x",
 		  WIPHY_PR_ARG, CHAN_DEF_PR_ARG, __entry->iftype,
-		  BOOL_TO_STR(__entry->check_no_ir))
+		  __entry->prohibited_flags, __entry->permitting_flags)
 );
 
 TRACE_EVENT(cfg80211_chandef_dfs_required,