cfg80211: allow wiphy specific regdomain management

Add a new regulatory flag that allows a driver to manage regdomain
changes/updates for its own wiphy.
A self-managed wiphys only employs regulatory information obtained from
the FW and driver and does not use other cfg80211 sources like
beacon-hints, country-code IEs and hints from other devices on the same
system. Conversely, a self-managed wiphy does not share its regulatory
hints with other devices in the system. If a system contains several
devices, one or more of which are self-managed, there might be
contradictory regulatory settings between them. Usage of flag is
generally discouraged. Only use it if the FW/driver is incompatible
with non-locally originated hints.

A new API lets the driver send a complete regdomain, to be applied on
its wiphy only.

After a wiphy-specific regdomain change takes place, usermode will get
a new type of change notification. The regulatory core also takes care
enforce regulatory restrictions, in case some interfaces are on
forbidden channels.

Signed-off-by: Jonathan Doron <jonathanx.doron@intel.com>
Signed-off-by: Arik Nemtsov <arikx.nemtsov@intel.com>
Reviewed-by: Luis R. Rodriguez <mcgrof@suse.com>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>

include/net/cfg80211.h

@@ -3807,6 +3807,20 @@ const u8 *cfg80211_find_vendor_ie(unsigned int oui, u8 oui_type,
  */
 int regulatory_hint(struct wiphy *wiphy, const char *alpha2);
 
+/**
+ * regulatory_set_wiphy_regd - set regdom info for self managed drivers
+ * @wiphy: the wireless device we want to process the regulatory domain on
+ * @rd: the regulatory domain informatoin to use for this wiphy
+ *
+ * Set the regulatory domain information for self-managed wiphys, only they
+ * may use this function. See %REGULATORY_WIPHY_SELF_MANAGED for more
+ * information.
+ *
+ * Return: 0 on success. -EINVAL, -EPERM
+ */
+int regulatory_set_wiphy_regd(struct wiphy *wiphy,
+			      struct ieee80211_regdomain *rd);
+
 /**
  * wiphy_apply_custom_regulatory - apply a custom driver regulatory domain
  * @wiphy: the wireless device we want to process the regulatory domain on

include/net/regulatory.h

@@ -147,6 +147,24 @@ struct regulatory_request {
  *	NL80211_IFTYPE_P2P_CLIENT, NL80211_IFTYPE_P2P_GO,
  *	NL80211_IFTYPE_P2P_DEVICE. The flag will be set by default if a device
  *	includes any modes unsupported for enforcement checking.
+ * @REGULATORY_WIPHY_SELF_MANAGED: for devices that employ wiphy-specific
+ *	regdom management. These devices will ignore all regdom changes not
+ *	originating from their own wiphy.
+ *	A self-managed wiphys only employs regulatory information obtained from
+ *	the FW and driver and does not use other cfg80211 sources like
+ *	beacon-hints, country-code IEs and hints from other devices on the same
+ *	system. Conversely, a self-managed wiphy does not share its regulatory
+ *	hints with other devices in the system. If a system contains several
+ *	devices, one or more of which are self-managed, there might be
+ *	contradictory regulatory settings between them. Usage of flag is
+ *	generally discouraged. Only use it if the FW/driver is incompatible
+ *	with non-locally originated hints.
+ *	This flag is incompatible with the flags: %REGULATORY_CUSTOM_REG,
+ *	%REGULATORY_STRICT_REG, %REGULATORY_COUNTRY_IE_FOLLOW_POWER,
+ *	%REGULATORY_COUNTRY_IE_IGNORE and %REGULATORY_DISABLE_BEACON_HINTS.
+ *	Mixing any of the above flags with this flag will result in a failure
+ *	to register the wiphy. This flag implies
+ *	%REGULATORY_DISABLE_BEACON_HINTS and %REGULATORY_COUNTRY_IE_IGNORE.
  */
 enum ieee80211_regulatory_flags {
 	REGULATORY_CUSTOM_REG			= BIT(0),
@@ -156,6 +174,7 @@ enum ieee80211_regulatory_flags {
 	REGULATORY_COUNTRY_IE_IGNORE		= BIT(4),
 	REGULATORY_ENABLE_RELAX_NO_IR           = BIT(5),
 	REGULATORY_IGNORE_STALE_KICKOFF         = BIT(6),
+	REGULATORY_WIPHY_SELF_MANAGED		= BIT(7),
 };
 
 struct ieee80211_freq_range {

include/uapi/linux/nl80211.h

@@ -782,6 +782,10 @@
  *	peer given by %NL80211_ATTR_MAC. Both peers must be on the base channel
  *	when this command completes.
  *
+ * @NL80211_CMD_WIPHY_REG_CHANGE: Similar to %NL80211_CMD_REG_CHANGE, but used
+ *	as an event to indicate changes for devices with wiphy-specific regdom
+ *	management.
+ *
  * @NL80211_CMD_MAX: highest used command number
  * @__NL80211_CMD_AFTER_LAST: internal use
  */
@@ -966,6 +970,8 @@ enum nl80211_commands {
 	NL80211_CMD_TDLS_CHANNEL_SWITCH,
 	NL80211_CMD_TDLS_CANCEL_CHANNEL_SWITCH,
 
+	NL80211_CMD_WIPHY_REG_CHANGE,
+
 	/* add new commands above here */
 
 	/* used to define NL80211_CMD_MAX below */

net/wireless/core.c

@@ -561,6 +561,14 @@ int wiphy_register(struct wiphy *wiphy)
 				       BIT(NL80211_IFTYPE_MONITOR)))
 		wiphy->regulatory_flags |= REGULATORY_IGNORE_STALE_KICKOFF;
 
+	if (WARN_ON((wiphy->regulatory_flags & REGULATORY_WIPHY_SELF_MANAGED) &&
+		    (wiphy->regulatory_flags &
+					(REGULATORY_CUSTOM_REG |
+					 REGULATORY_STRICT_REG |
+					 REGULATORY_COUNTRY_IE_FOLLOW_POWER |
+					 REGULATORY_COUNTRY_IE_IGNORE))))
+		return -EINVAL;
+
 	if (WARN_ON(wiphy->coalesce &&
 		    (!wiphy->coalesce->n_rules ||
 		     !wiphy->coalesce->n_patterns) &&

net/wireless/core.h

@@ -36,6 +36,13 @@ struct cfg80211_registered_device {
 	 * the country on the country IE changed. */
 	char country_ie_alpha2[2];
 
+	/*
+	 * the driver requests the regulatory core to set this regulatory
+	 * domain as the wiphy's. Only used for %REGULATORY_WIPHY_SELF_MANAGED
+	 * devices using the regulatory_set_wiphy_regd() API
+	 */
+	const struct ieee80211_regdomain *requested_regd;
+
 	/* If a Country IE has been received this tells us the environment
 	 * which its telling us its in. This defaults to ENVIRON_ANY */
 	enum environment_cap env;

net/wireless/nl80211.c

@@ -11042,25 +11042,9 @@ void nl80211_send_sched_scan(struct cfg80211_registered_device *rdev,
 				NL80211_MCGRP_SCAN, GFP_KERNEL);
 }
 
-/*
- * This can happen on global regulatory changes or device specific settings
- * based on custom world regulatory domains.
- */
-void nl80211_send_reg_change_event(struct regulatory_request *request)
+static bool nl80211_reg_change_event_fill(struct sk_buff *msg,
+					  struct regulatory_request *request)
 {
-	struct sk_buff *msg;
-	void *hdr;
-
-	msg = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_KERNEL);
-	if (!msg)
-		return;
-
-	hdr = nl80211hdr_put(msg, 0, 0, 0, NL80211_CMD_REG_CHANGE);
-	if (!hdr) {
-		nlmsg_free(msg);
-		return;
-	}
-
 	/* Userspace can always count this one always being set */
 	if (nla_put_u8(msg, NL80211_ATTR_REG_INITIATOR, request->initiator))
 		goto nla_put_failure;
@@ -11094,6 +11078,35 @@ void nl80211_send_reg_change_event(struct regulatory_request *request)
 			goto nla_put_failure;
 	}
 
+	return true;
+
+nla_put_failure:
+	return false;
+}
+
+/*
+ * This can happen on global regulatory changes or device specific settings
+ * based on custom regulatory domains.
+ */
+void nl80211_common_reg_change_event(enum nl80211_commands cmd_id,
+				     struct regulatory_request *request)
+{
+	struct sk_buff *msg;
+	void *hdr;
+
+	msg = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_KERNEL);
+	if (!msg)
+		return;
+
+	hdr = nl80211hdr_put(msg, 0, 0, 0, cmd_id);
+	if (!hdr) {
+		nlmsg_free(msg);
+		return;
+	}
+
+	if (nl80211_reg_change_event_fill(msg, request) == false)
+		goto nla_put_failure;
+
 	genlmsg_end(msg, hdr);
 
 	rcu_read_lock();

net/wireless/nl80211.h

@@ -17,7 +17,21 @@ void nl80211_send_sched_scan(struct cfg80211_registered_device *rdev,
 			     struct net_device *netdev, u32 cmd);
 void nl80211_send_sched_scan_results(struct cfg80211_registered_device *rdev,
 				     struct net_device *netdev);
-void nl80211_send_reg_change_event(struct regulatory_request *request);
+void nl80211_common_reg_change_event(enum nl80211_commands cmd_id,
+				     struct regulatory_request *request);
+
+static inline void
+nl80211_send_reg_change_event(struct regulatory_request *request)
+{
+	nl80211_common_reg_change_event(NL80211_CMD_REG_CHANGE, request);
+}
+
+static inline void
+nl80211_send_wiphy_reg_change_event(struct regulatory_request *request)
+{
+	nl80211_common_reg_change_event(NL80211_CMD_WIPHY_REG_CHANGE, request);
+}
+
 void nl80211_send_rx_auth(struct cfg80211_registered_device *rdev,
 			  struct net_device *netdev,
 			  const u8 *buf, size_t len, gfp_t gfp);

net/wireless/reg.c

@@ -1307,6 +1307,9 @@ static bool ignore_reg_update(struct wiphy *wiphy,
 {
 	struct regulatory_request *lr = get_last_request();
 
+	if (wiphy->regulatory_flags & REGULATORY_WIPHY_SELF_MANAGED)
+		return true;
+
 	if (!lr) {
 		REG_DBG_PRINT("Ignoring regulatory request set by %s "
 			      "since last_request is not set\n",
@@ -2147,11 +2150,52 @@ static void reg_process_pending_beacon_hints(void)
 	spin_unlock_bh(&reg_pending_beacons_lock);
 }
 
+static void reg_process_self_managed_hints(void)
+{
+	struct cfg80211_registered_device *rdev;
+	struct wiphy *wiphy;
+	const struct ieee80211_regdomain *tmp;
+	const struct ieee80211_regdomain *regd;
+	enum ieee80211_band band;
+	struct regulatory_request request = {};
+
+	list_for_each_entry(rdev, &cfg80211_rdev_list, list) {
+		wiphy = &rdev->wiphy;
+
+		spin_lock(&reg_requests_lock);
+		regd = rdev->requested_regd;
+		rdev->requested_regd = NULL;
+		spin_unlock(&reg_requests_lock);
+
+		if (regd == NULL)
+			continue;
+
+		tmp = get_wiphy_regdom(wiphy);
+		rcu_assign_pointer(wiphy->regd, regd);
+		rcu_free_regdom(tmp);
+
+		for (band = 0; band < IEEE80211_NUM_BANDS; band++)
+			handle_band_custom(wiphy, wiphy->bands[band], regd);
+
+		reg_process_ht_flags(wiphy);
+
+		request.wiphy_idx = get_wiphy_idx(wiphy);
+		request.alpha2[0] = regd->alpha2[0];
+		request.alpha2[1] = regd->alpha2[1];
+		request.initiator = NL80211_REGDOM_SET_BY_DRIVER;
+
+		nl80211_send_wiphy_reg_change_event(&request);
+	}
+
+	reg_check_channels();
+}
+
 static void reg_todo(struct work_struct *work)
 {
 	rtnl_lock();
 	reg_process_pending_hints();
 	reg_process_pending_beacon_hints();
+	reg_process_self_managed_hints();
 	rtnl_unlock();
 }
 
@@ -2432,6 +2476,8 @@ static void restore_regulatory_settings(bool reset_user)
 	world_alpha2[1] = cfg80211_world_regdom->alpha2[1];
 
 	list_for_each_entry(rdev, &cfg80211_rdev_list, list) {
+		if (rdev->wiphy.regulatory_flags & REGULATORY_WIPHY_SELF_MANAGED)
+			continue;
 		if (rdev->wiphy.regulatory_flags & REGULATORY_CUSTOM_REG)
 			restore_custom_reg_settings(&rdev->wiphy);
 	}
@@ -2835,10 +2881,52 @@ int set_regdom(const struct ieee80211_regdomain *rd)
 	return 0;
 }
 
+int regulatory_set_wiphy_regd(struct wiphy *wiphy,
+			      struct ieee80211_regdomain *rd)
+{
+	const struct ieee80211_regdomain *regd;
+	const struct ieee80211_regdomain *prev_regd;
+	struct cfg80211_registered_device *rdev;
+
+	if (WARN_ON(!wiphy || !rd))
+		return -EINVAL;
+
+	if (WARN(!(wiphy->regulatory_flags & REGULATORY_WIPHY_SELF_MANAGED),
+		 "wiphy should have REGULATORY_WIPHY_SELF_MANAGED\n"))
+		return -EPERM;
+
+	if (WARN(!is_valid_rd(rd), "Invalid regulatory domain detected\n")) {
+		print_regdomain_info(rd);
+		return -EINVAL;
+	}
+
+	regd = reg_copy_regd(rd);
+	if (IS_ERR(regd))
+		return PTR_ERR(regd);
+
+	rdev = wiphy_to_rdev(wiphy);
+
+	spin_lock(&reg_requests_lock);
+	prev_regd = rdev->requested_regd;
+	rdev->requested_regd = regd;
+	spin_unlock(&reg_requests_lock);
+
+	kfree(prev_regd);
+
+	schedule_work(&reg_work);
+	return 0;
+}
+EXPORT_SYMBOL(regulatory_set_wiphy_regd);
+
 void wiphy_regulatory_register(struct wiphy *wiphy)
 {
 	struct regulatory_request *lr;
 
+	/* self-managed devices ignore external hints */
+	if (wiphy->regulatory_flags & REGULATORY_WIPHY_SELF_MANAGED)
+		wiphy->regulatory_flags |= REGULATORY_DISABLE_BEACON_HINTS |
+					   REGULATORY_COUNTRY_IE_IGNORE;
+
 	if (!reg_dev_ignore_cell_hint(wiphy))
 		reg_num_devs_support_basehint++;