nl80211: Add support to set AP settings flags with single attribute

In previous method each AP settings flag is represented by a top-level
flag attribute and conversion to enum cfg80211_ap_settings_flags had to
be done before sending them to driver. This commit is to make it easier
to define new AP settings flags and sending them to driver.

This commit also deprecate sending of
%NL80211_ATTR_EXTERNAL_AUTH_SUPPORT in %NL80211_CMD_START_AP. But to
maintain backwards compatibility checks for
%NL80211_ATTR_EXTERNAL_AUTH_SUPPORT in %NL80211_CMD_START_AP when
%NL80211_ATTR_AP_SETTINGS_FLAGS not present in %NL80211_CMD_START_AP.

Signed-off-by: Veerendranath Jakkam <vjakkam@codeaurora.org>
Link: https://lore.kernel.org/r/1637911519-21306-1-git-send-email-vjakkam@codeaurora.org
Signed-off-by: Johannes Berg <johannes.berg@intel.com>

include/net/cfg80211.h

@@ -1187,17 +1187,6 @@ struct cfg80211_unsol_bcast_probe_resp {
 	const u8 *tmpl;
 };
 
-/**
- * enum cfg80211_ap_settings_flags - AP settings flags
- *
- * Used by cfg80211_ap_settings
- *
- * @AP_SETTINGS_EXTERNAL_AUTH_SUPPORT: AP supports external authentication
- */
-enum cfg80211_ap_settings_flags {
-	AP_SETTINGS_EXTERNAL_AUTH_SUPPORT = BIT(0),
-};
-
 /**
  * struct cfg80211_ap_settings - AP configuration
  *

include/uapi/linux/nl80211.h

@@ -2477,7 +2477,9 @@ enum nl80211_commands {
  *	space supports external authentication. This attribute shall be used
  *	with %NL80211_CMD_CONNECT and %NL80211_CMD_START_AP request. The driver
  *	may offload authentication processing to user space if this capability
- *	is indicated in the respective requests from the user space.
+ *	is indicated in the respective requests from the user space. (This flag
+ *	attribute deprecated for %NL80211_CMD_START_AP, use
+ *	%NL80211_ATTR_AP_SETTINGS_FLAGS)
  *
  * @NL80211_ATTR_NSS: Station's New/updated  RX_NSS value notified using this
  *	u8 attribute. This is used with %NL80211_CMD_STA_OPMODE_CHANGED.
@@ -2653,6 +2655,10 @@ enum nl80211_commands {
  *	switching on a different channel during CAC detection on the selected
  *	radar channel.
  *
+ * @NL80211_ATTR_AP_SETTINGS_FLAGS: u32 attribute contains ap settings flags,
+ *	enumerated in &enum nl80211_ap_settings_flags. This attribute shall be
+ *	used with %NL80211_CMD_START_AP request.
+ *
  * @NUM_NL80211_ATTR: total number of nl80211_attrs available
  * @NL80211_ATTR_MAX: highest attribute number currently defined
  * @__NL80211_ATTR_AFTER_LAST: internal use
@@ -3161,6 +3167,8 @@ enum nl80211_attrs {
 
 	NL80211_ATTR_RADAR_BACKGROUND,
 
+	NL80211_ATTR_AP_SETTINGS_FLAGS,
+
 	/* add attributes here, update the policy in nl80211.c */
 
 	__NL80211_ATTR_AFTER_LAST,
@@ -7481,4 +7489,14 @@ enum nl80211_mbssid_config_attributes {
 	NL80211_MBSSID_CONFIG_ATTR_MAX = __NL80211_MBSSID_CONFIG_ATTR_LAST - 1,
 };
 
+/**
+ * enum nl80211_ap_settings_flags - AP settings flags
+ *
+ * @NL80211_AP_SETTINGS_EXTERNAL_AUTH_SUPPORT: AP supports external
+ *	authentication.
+ */
+enum nl80211_ap_settings_flags {
+	NL80211_AP_SETTINGS_EXTERNAL_AUTH_SUPPORT	= 1 << 0,
+};
+
 #endif /* __LINUX_NL80211_H */

net/wireless/nl80211.c

@@ -777,6 +777,7 @@ static const struct nla_policy nl80211_policy[NUM_NL80211_ATTR] = {
 			NLA_POLICY_NESTED(nl80211_mbssid_config_policy),
 	[NL80211_ATTR_MBSSID_ELEMS] = { .type = NLA_NESTED },
 	[NL80211_ATTR_RADAR_BACKGROUND] = { .type = NLA_FLAG },
+	[NL80211_ATTR_AP_SETTINGS_FLAGS] = { .type = NLA_U32 },
 };
 
 /* policy for the key attributes */
@@ -5714,8 +5715,11 @@ static int nl80211_start_ap(struct sk_buff *skb, struct genl_info *info)
 
 	nl80211_calculate_ap_params(params);
 
-	if (info->attrs[NL80211_ATTR_EXTERNAL_AUTH_SUPPORT])
-		params->flags |= AP_SETTINGS_EXTERNAL_AUTH_SUPPORT;
+	if (info->attrs[NL80211_ATTR_AP_SETTINGS_FLAGS])
+		params->flags = nla_get_u32(
+			info->attrs[NL80211_ATTR_AP_SETTINGS_FLAGS]);
+	else if (info->attrs[NL80211_ATTR_EXTERNAL_AUTH_SUPPORT])
+		params->flags |= NL80211_AP_SETTINGS_EXTERNAL_AUTH_SUPPORT;
 
 	wdev_lock(wdev);
 	err = rdev_start_ap(rdev, dev, params);