updating github.com/miekg/dns to v1.1.4

vendor/github.com/miekg/dns/duplicate.go

@@ -0,0 +1,38 @@
+package dns
+
+//go:generate go run duplicate_generate.go
+
+// IsDuplicate checks of r1 and r2 are duplicates of each other, excluding the TTL.
+// So this means the header data is equal *and* the RDATA is the same. Return true
+// is so, otherwise false.
+// It's is a protocol violation to have identical RRs in a message.
+func IsDuplicate(r1, r2 RR) bool {
+	// Check whether the record header is identical.
+	if !r1.Header().isDuplicate(r2.Header()) {
+		return false
+	}
+
+	// Check whether the RDATA is identical.
+	return r1.isDuplicate(r2)
+}
+
+func (r1 *RR_Header) isDuplicate(_r2 RR) bool {
+	r2, ok := _r2.(*RR_Header)
+	if !ok {
+		return false
+	}
+	if r1.Class != r2.Class {
+		return false
+	}
+	if r1.Rrtype != r2.Rrtype {
+		return false
+	}
+	if !isDulicateName(r1.Name, r2.Name) {
+		return false
+	}
+	// ignore TTL
+	return true
+}
+
+// isDulicateName checks if the domain names s1 and s2 are equal.
+func isDulicateName(s1, s2 string) bool { return equal(s1, s2) }