diff --git a/msg.go b/msg.go
index 5cb8f274..cd86b0fb 100644
--- a/msg.go
+++ b/msg.go
@@ -1079,7 +1079,7 @@ func unpackRR(msg []byte, off int) (rr RR, off1 int, ok bool) {
 	}
 	end := off + int(h.Rdlength)
 	// make an rr of that type and re-unpack.
-	mk, known := rr_mk[h.Rrtype]
+	mk, known := Rr_mk[h.Rrtype]
 	if !known {
 		rr = new(RR_RFC3597)
 	} else {
diff --git a/types.go b/types.go
index 73c87104..cb9352fb 100644
--- a/types.go
+++ b/types.go
@@ -1400,7 +1400,7 @@ func cmToString(mantissa, exponent uint8) string {
 }
 
 // Map of constructors for each RR wire type.
-var rr_mk = map[uint16]func() RR{
+var Rr_mk = map[uint16]func() RR{
 	TypeCNAME:      func() RR { return new(RR_CNAME) },
 	TypeHINFO:      func() RR { return new(RR_HINFO) },
 	TypeMB:         func() RR { return new(RR_MB) },