2 files changed, 45 insertions, 0 deletions
diff --git a/plugin/pkg/rcode/rcode.go b/plugin/pkg/rcode/rcode.go
new file mode 100644
index 000000000..32863f0b2
--- /dev/null
+++ b/plugin/pkg/rcode/rcode.go
@@ -0,0 +1,16 @@
+package rcode
+
+import (
+	"strconv"
+
+	"github.com/miekg/dns"
+)
+
+// ToString convert the rcode to the official DNS string, or to "RCODE"+value if the RCODE
+// value is unknown.
+func ToString(rcode int) string {
+	if str, ok := dns.RcodeToString[rcode]; ok {
+		return str
+	}
+	return "RCODE" + strconv.Itoa(rcode)
+}
diff --git a/plugin/pkg/rcode/rcode_test.go b/plugin/pkg/rcode/rcode_test.go
new file mode 100644
index 000000000..bfca32f1d
--- /dev/null
+++ b/plugin/pkg/rcode/rcode_test.go
@@ -0,0 +1,29 @@
+package rcode
+
+import (
+	"testing"
+
+	"github.com/miekg/dns"
+)
+
+func TestToString(t *testing.T) {
+	tests := []struct {
+		in       int
+		expected string
+	}{
+		{
+			dns.RcodeSuccess,
+			"NOERROR",
+		},
+		{
+			28,
+			"RCODE28",
+		},
+	}
+	for i, test := range tests {
+		got := ToString(test.in)
+		if got != test.expected {
+			t.Errorf("Test %d, expected %s, got %s", i, test.expected, got)
+		}
+	}
+}