cfg80211: allow the user space to change current NAN configuration

Some NAN configuration paramaters may change during the operation of
the NAN device. For example, a user may want to update master preference
value when the device gets plugged/unplugged to the power.
Add API that allows to do so.

Signed-off-by: Andrei Otcheretianski <andrei.otcheretianski@intel.com>
Signed-off-by: Emmanuel Grumbach <emmanuel.grumbach@intel.com>
Signed-off-by: Luca Coelho <luciano.coelho@intel.com>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
diff --git a/net/wireless/nl80211.c b/net/wireless/nl80211.c
index 0eca59c..c0b5ae4 100644
--- a/net/wireless/nl80211.c
+++ b/net/wireless/nl80211.c
@@ -10919,6 +10919,40 @@
 	return 0;
 }
 
+static int nl80211_nan_change_config(struct sk_buff *skb,
+				     struct genl_info *info)
+{
+	struct cfg80211_registered_device *rdev = info->user_ptr[0];
+	struct wireless_dev *wdev = info->user_ptr[1];
+	struct cfg80211_nan_conf conf = {};
+	u32 changed = 0;
+
+	if (wdev->iftype != NL80211_IFTYPE_NAN)
+		return -EOPNOTSUPP;
+
+	if (!wdev->nan_started)
+		return -ENOTCONN;
+
+	if (info->attrs[NL80211_ATTR_NAN_MASTER_PREF]) {
+		conf.master_pref =
+			nla_get_u8(info->attrs[NL80211_ATTR_NAN_MASTER_PREF]);
+		if (conf.master_pref <= 1 || conf.master_pref == 255)
+			return -EINVAL;
+
+		changed |= CFG80211_NAN_CONF_CHANGED_PREF;
+	}
+
+	if (info->attrs[NL80211_ATTR_NAN_DUAL]) {
+		conf.dual = nla_get_u8(info->attrs[NL80211_ATTR_NAN_DUAL]);
+		changed |= CFG80211_NAN_CONF_CHANGED_DUAL;
+	}
+
+	if (!changed)
+		return -EINVAL;
+
+	return rdev_nan_change_conf(rdev, wdev, &conf, changed);
+}
+
 static int nl80211_get_protocol_features(struct sk_buff *skb,
 					 struct genl_info *info)
 {
@@ -12293,6 +12327,14 @@
 				  NL80211_FLAG_NEED_RTNL,
 	},
 	{
+		.cmd = NL80211_CMD_CHANGE_NAN_CONFIG,
+		.doit = nl80211_nan_change_config,
+		.policy = nl80211_policy,
+		.flags = GENL_ADMIN_PERM,
+		.internal_flags = NL80211_FLAG_NEED_WDEV_UP |
+				  NL80211_FLAG_NEED_RTNL,
+	},
+	{
 		.cmd = NL80211_CMD_SET_MCAST_RATE,
 		.doit = nl80211_set_mcast_rate,
 		.policy = nl80211_policy,