1 files changed, 13 insertions, 0 deletions
diff --git a/plugin/file/wildcard.go b/plugin/file/wildcard.go
new file mode 100644
index 000000000..9526cb53f
--- /dev/null
+++ b/plugin/file/wildcard.go
@@ -0,0 +1,13 @@
+package file
+
+import "github.com/miekg/dns"
+
+// replaceWithWildcard replaces the left most label with '*'.
+func replaceWithAsteriskLabel(qname string) (wildcard string) {
+	i, shot := dns.NextLabel(qname, 0)
+	if shot {
+		return ""
+	}
+
+	return "*." + qname[i:]
+}