Feature: move hosts to the top

dns/iputil.go

@@ -9,8 +9,74 @@ var (
 	errIPNotFound = errors.New("cannot found ip")
 )
 
+// ResolveIPv4 with a host, return ipv4
+func ResolveIPv4(host string) (net.IP, error) {
+	if node := DefaultHosts.Search(host); node != nil {
+		if ip := node.Data.(net.IP).To4(); ip != nil {
+			return ip, nil
+		}
+	}
+
+	ip := net.ParseIP(host)
+	if ip4 := ip.To4(); ip4 != nil {
+		return ip4, nil
+	}
+
+	if DefaultResolver != nil {
+		return DefaultResolver.ResolveIPv4(host)
+	}
+
+	ipAddrs, err := net.LookupIP(host)
+	if err != nil {
+		return nil, err
+	}
+
+	for _, ip := range ipAddrs {
+		if ip4 := ip.To4(); ip4 != nil {
+			return ip4, nil
+		}
+	}
+
+	return nil, errIPNotFound
+}
+
+// ResolveIPv6 with a host, return ipv6
+func ResolveIPv6(host string) (net.IP, error) {
+	if node := DefaultHosts.Search(host); node != nil {
+		if ip := node.Data.(net.IP).To16(); ip != nil {
+			return ip, nil
+		}
+	}
+
+	ip := net.ParseIP(host)
+	if ip6 := ip.To16(); ip6 != nil {
+		return ip6, nil
+	}
+
+	if DefaultResolver != nil {
+		return DefaultResolver.ResolveIPv6(host)
+	}
+
+	ipAddrs, err := net.LookupIP(host)
+	if err != nil {
+		return nil, err
+	}
+
+	for _, ip := range ipAddrs {
+		if ip6 := ip.To16(); ip6 != nil {
+			return ip6, nil
+		}
+	}
+
+	return nil, errIPNotFound
+}
+
 // ResolveIP with a host, return ip
 func ResolveIP(host string) (net.IP, error) {
+	if node := DefaultHosts.Search(host); node != nil {
+		return node.Data.(net.IP), nil
+	}
+
 	if DefaultResolver != nil {
 		if DefaultResolver.ipv6 {
 			return DefaultResolver.ResolveIP(host)