refactor: new dns app

app/dns/nameserver_local.go

@@ -0,0 +1,41 @@
+package dns
+
+import (
+	"context"
+
+	"github.com/xtls/xray-core/common/net"
+	"github.com/xtls/xray-core/features/dns"
+	"github.com/xtls/xray-core/features/dns/localdns"
+)
+
+// LocalNameServer is an wrapper over local DNS feature.
+type LocalNameServer struct {
+	client *localdns.Client
+}
+
+// QueryIP implements Server.
+func (s *LocalNameServer) QueryIP(_ context.Context, domain string, _ net.IP, option dns.IPOption, _ bool) ([]net.IP, error) {
+	if option.IPv4Enable || option.IPv6Enable {
+		return s.client.LookupIP(domain, option)
+	}
+
+	return nil, newError("neither IPv4 nor IPv6 is enabled")
+}
+
+// Name implements Server.
+func (s *LocalNameServer) Name() string {
+	return "localhost"
+}
+
+// NewLocalNameServer creates localdns server object for directly lookup in system DNS.
+func NewLocalNameServer() *LocalNameServer {
+	newError("DNS: created localhost client").AtInfo().WriteToLog()
+	return &LocalNameServer{
+		client: localdns.New(),
+	}
+}
+
+// NewLocalDNSClient creates localdns client object for directly lookup in system DNS.
+func NewLocalDNSClient() *Client {
+	return &Client{server: NewLocalNameServer()}
+}