DNS Header for KCP (#1672)

* dns header

* fixed domain name encoding for dns header

---------

Co-authored-by: kerry <lvhaiyangkerry@gmail.com>

infra/conf/transport_authenticators.go

@@ -4,6 +4,7 @@ import (
 	"sort"
 
 	"github.com/golang/protobuf/proto"
+	"github.com/xtls/xray-core/transport/internet/headers/dns"
 	"github.com/xtls/xray-core/transport/internet/headers/http"
 	"github.com/xtls/xray-core/transport/internet/headers/noop"
 	"github.com/xtls/xray-core/transport/internet/headers/srtp"
@@ -49,6 +50,19 @@ func (WireguardAuthenticator) Build() (proto.Message, error) {
 	return new(wireguard.WireguardConfig), nil
 }
 
+type DNSAuthenticator struct {
+	Domain string `json:"domain"`
+}
+
+func (v *DNSAuthenticator) Build() (proto.Message, error) {
+	config := new(dns.Config)
+	config.Domain = "www.baidu.com"
+	if len(v.Domain) > 0 {
+		config.Domain = v.Domain
+	}
+	return config, nil
+}
+
 type DTLSAuthenticator struct{}
 
 func (DTLSAuthenticator) Build() (proto.Message, error) {

infra/conf/transport_internet.go

@@ -37,6 +37,7 @@ var (
 		"wechat-video": func() interface{} { return new(WechatVideoAuthenticator) },
 		"dtls":         func() interface{} { return new(DTLSAuthenticator) },
 		"wireguard":    func() interface{} { return new(WireguardAuthenticator) },
+		"dns":          func() interface{} { return new(DNSAuthenticator) },
 	}, "type", "")
 
 	tcpHeaderLoader = NewJSONConfigLoader(ConfigCreatorCache{

transport/internet/headers/dns/config.pb.go

@@ -0,0 +1,153 @@
+// Code generated by protoc-gen-go. DO NOT EDIT.
+// versions:
+// 	protoc-gen-go v1.28.1
+// 	protoc        v3.21.12
+// source: transport/internet/headers/dns/config.proto
+
+package dns
+
+import (
+	protoreflect "google.golang.org/protobuf/reflect/protoreflect"
+	protoimpl "google.golang.org/protobuf/runtime/protoimpl"
+	reflect "reflect"
+	sync "sync"
+)
+
+const (
+	// Verify that this generated code is sufficiently up-to-date.
+	_ = protoimpl.EnforceVersion(20 - protoimpl.MinVersion)
+	// Verify that runtime/protoimpl is sufficiently up-to-date.
+	_ = protoimpl.EnforceVersion(protoimpl.MaxVersion - 20)
+)
+
+type Config struct {
+	state         protoimpl.MessageState
+	sizeCache     protoimpl.SizeCache
+	unknownFields protoimpl.UnknownFields
+
+	Domain string `protobuf:"bytes,1,opt,name=domain,proto3" json:"domain,omitempty"`
+}
+
+func (x *Config) Reset() {
+	*x = Config{}
+	if protoimpl.UnsafeEnabled {
+		mi := &file_transport_internet_headers_dns_config_proto_msgTypes[0]
+		ms := protoimpl.X.MessageStateOf(protoimpl.Pointer(x))
+		ms.StoreMessageInfo(mi)
+	}
+}
+
+func (x *Config) String() string {
+	return protoimpl.X.MessageStringOf(x)
+}
+
+func (*Config) ProtoMessage() {}
+
+func (x *Config) ProtoReflect() protoreflect.Message {
+	mi := &file_transport_internet_headers_dns_config_proto_msgTypes[0]
+	if protoimpl.UnsafeEnabled && x != nil {
+		ms := protoimpl.X.MessageStateOf(protoimpl.Pointer(x))
+		if ms.LoadMessageInfo() == nil {
+			ms.StoreMessageInfo(mi)
+		}
+		return ms
+	}
+	return mi.MessageOf(x)
+}
+
+// Deprecated: Use Config.ProtoReflect.Descriptor instead.
+func (*Config) Descriptor() ([]byte, []int) {
+	return file_transport_internet_headers_dns_config_proto_rawDescGZIP(), []int{0}
+}
+
+func (x *Config) GetDomain() string {
+	if x != nil {
+		return x.Domain
+	}
+	return ""
+}
+
+var File_transport_internet_headers_dns_config_proto protoreflect.FileDescriptor
+
+var file_transport_internet_headers_dns_config_proto_rawDesc = []byte{
+	0x0a, 0x2b, 0x74, 0x72, 0x61, 0x6e, 0x73, 0x70, 0x6f, 0x72, 0x74, 0x2f, 0x69, 0x6e, 0x74, 0x65,
+	0x72, 0x6e, 0x65, 0x74, 0x2f, 0x68, 0x65, 0x61, 0x64, 0x65, 0x72, 0x73, 0x2f, 0x64, 0x6e, 0x73,
+	0x2f, 0x63, 0x6f, 0x6e, 0x66, 0x69, 0x67, 0x2e, 0x70, 0x72, 0x6f, 0x74, 0x6f, 0x12, 0x23, 0x78,
+	0x72, 0x61, 0x79, 0x2e, 0x74, 0x72, 0x61, 0x6e, 0x73, 0x70, 0x6f, 0x72, 0x74, 0x2e, 0x69, 0x6e,
+	0x74, 0x65, 0x72, 0x6e, 0x65, 0x74, 0x2e, 0x68, 0x65, 0x61, 0x64, 0x65, 0x72, 0x73, 0x2e, 0x64,
+	0x6e, 0x73, 0x22, 0x20, 0x0a, 0x06, 0x43, 0x6f, 0x6e, 0x66, 0x69, 0x67, 0x12, 0x16, 0x0a, 0x06,
+	0x64, 0x6f, 0x6d, 0x61, 0x69, 0x6e, 0x18, 0x01, 0x20, 0x01, 0x28, 0x09, 0x52, 0x06, 0x64, 0x6f,
+	0x6d, 0x61, 0x69, 0x6e, 0x42, 0x8b, 0x01, 0x0a, 0x27, 0x63, 0x6f, 0x6d, 0x2e, 0x78, 0x72, 0x61,
+	0x79, 0x2e, 0x74, 0x72, 0x61, 0x6e, 0x73, 0x70, 0x6f, 0x72, 0x74, 0x2e, 0x69, 0x6e, 0x74, 0x65,
+	0x72, 0x6e, 0x65, 0x74, 0x2e, 0x68, 0x65, 0x61, 0x64, 0x65, 0x72, 0x73, 0x2e, 0x64, 0x6e, 0x73,
+	0x50, 0x01, 0x5a, 0x38, 0x67, 0x69, 0x74, 0x68, 0x75, 0x62, 0x2e, 0x63, 0x6f, 0x6d, 0x2f, 0x78,
+	0x74, 0x6c, 0x73, 0x2f, 0x78, 0x72, 0x61, 0x79, 0x2d, 0x63, 0x6f, 0x72, 0x65, 0x2f, 0x74, 0x72,
+	0x61, 0x6e, 0x73, 0x70, 0x6f, 0x72, 0x74, 0x2f, 0x69, 0x6e, 0x74, 0x65, 0x72, 0x6e, 0x65, 0x74,
+	0x2f, 0x68, 0x65, 0x61, 0x64, 0x65, 0x72, 0x73, 0x2f, 0x64, 0x6e, 0x73, 0xaa, 0x02, 0x23, 0x58,
+	0x72, 0x61, 0x79, 0x2e, 0x54, 0x72, 0x61, 0x6e, 0x73, 0x70, 0x6f, 0x72, 0x74, 0x2e, 0x49, 0x6e,
+	0x74, 0x65, 0x72, 0x6e, 0x65, 0x74, 0x2e, 0x48, 0x65, 0x61, 0x64, 0x65, 0x72, 0x73, 0x2e, 0x44,
+	0x4e, 0x53, 0x62, 0x06, 0x70, 0x72, 0x6f, 0x74, 0x6f, 0x33,
+}
+
+var (
+	file_transport_internet_headers_dns_config_proto_rawDescOnce sync.Once
+	file_transport_internet_headers_dns_config_proto_rawDescData = file_transport_internet_headers_dns_config_proto_rawDesc
+)
+
+func file_transport_internet_headers_dns_config_proto_rawDescGZIP() []byte {
+	file_transport_internet_headers_dns_config_proto_rawDescOnce.Do(func() {
+		file_transport_internet_headers_dns_config_proto_rawDescData = protoimpl.X.CompressGZIP(file_transport_internet_headers_dns_config_proto_rawDescData)
+	})
+	return file_transport_internet_headers_dns_config_proto_rawDescData
+}
+
+var file_transport_internet_headers_dns_config_proto_msgTypes = make([]protoimpl.MessageInfo, 1)
+var file_transport_internet_headers_dns_config_proto_goTypes = []interface{}{
+	(*Config)(nil), // 0: xray.transport.internet.headers.dns.Config
+}
+var file_transport_internet_headers_dns_config_proto_depIdxs = []int32{
+	0, // [0:0] is the sub-list for method output_type
+	0, // [0:0] is the sub-list for method input_type
+	0, // [0:0] is the sub-list for extension type_name
+	0, // [0:0] is the sub-list for extension extendee
+	0, // [0:0] is the sub-list for field type_name
+}
+
+func init() { file_transport_internet_headers_dns_config_proto_init() }
+func file_transport_internet_headers_dns_config_proto_init() {
+	if File_transport_internet_headers_dns_config_proto != nil {
+		return
+	}
+	if !protoimpl.UnsafeEnabled {
+		file_transport_internet_headers_dns_config_proto_msgTypes[0].Exporter = func(v interface{}, i int) interface{} {
+			switch v := v.(*Config); i {
+			case 0:
+				return &v.state
+			case 1:
+				return &v.sizeCache
+			case 2:
+				return &v.unknownFields
+			default:
+				return nil
+			}
+		}
+	}
+	type x struct{}
+	out := protoimpl.TypeBuilder{
+		File: protoimpl.DescBuilder{
+			GoPackagePath: reflect.TypeOf(x{}).PkgPath(),
+			RawDescriptor: file_transport_internet_headers_dns_config_proto_rawDesc,
+			NumEnums:      0,
+			NumMessages:   1,
+			NumExtensions: 0,
+			NumServices:   0,
+		},
+		GoTypes:           file_transport_internet_headers_dns_config_proto_goTypes,
+		DependencyIndexes: file_transport_internet_headers_dns_config_proto_depIdxs,
+		MessageInfos:      file_transport_internet_headers_dns_config_proto_msgTypes,
+	}.Build()
+	File_transport_internet_headers_dns_config_proto = out.File
+	file_transport_internet_headers_dns_config_proto_rawDesc = nil
+	file_transport_internet_headers_dns_config_proto_goTypes = nil
+	file_transport_internet_headers_dns_config_proto_depIdxs = nil
+}

transport/internet/headers/dns/config.proto

@@ -0,0 +1,12 @@
+syntax = "proto3";
+
+package xray.transport.internet.headers.dns;
+option csharp_namespace = "Xray.Transport.Internet.Headers.DNS";
+option go_package = "github.com/xtls/xray-core/transport/internet/headers/dns";
+option java_package = "com.xray.transport.internet.headers.dns";
+option java_multiple_files = true;
+
+message Config {
+    string domain = 1;
+}
+

transport/internet/headers/dns/dns.go

@@ -0,0 +1,57 @@
+package dns
+
+import (
+	"context"
+	"encoding/binary"
+
+	"github.com/miekg/dns"
+	"github.com/xtls/xray-core/common"
+	"github.com/xtls/xray-core/common/dice"
+)
+
+type DNS struct {
+	header []byte
+}
+
+func (d DNS) Size() int32 {
+	return int32(len(d.header))
+}
+
+// Serialize implements PacketHeader.
+func (d DNS) Serialize(b []byte) {
+	copy(b, d.header)
+	binary.BigEndian.PutUint16(b[0:], dice.RollUint16()) // random transaction ID
+}
+
+// NewDNS returns a new DNS instance based on given config.
+func NewDNS(ctx context.Context, config interface{}) (interface{}, error) {
+	var header []byte
+
+	header = binary.BigEndian.AppendUint16(header, 0x0000) // Transaction ID
+	header = binary.BigEndian.AppendUint16(header, 0x0100) // Flags: Standard query
+	header = binary.BigEndian.AppendUint16(header, 0x0001) // Questions
+	header = binary.BigEndian.AppendUint16(header, 0x0000) // Answer RRs
+	header = binary.BigEndian.AppendUint16(header, 0x0000) // Authority RRs
+	header = binary.BigEndian.AppendUint16(header, 0x0000) // Additional RRs
+
+	buf := make([]byte, 0x100)
+
+	off1, err := dns.PackDomainName(dns.Fqdn(config.(*Config).Domain), buf, 0, nil, false)
+
+	if err != nil {
+		return nil, err
+	}
+
+	header = append(header, buf[:off1]...)
+
+	header = binary.BigEndian.AppendUint16(header, 0x0001) // Type: A
+	header = binary.BigEndian.AppendUint16(header, 0x0001) // Class: IN
+
+	return DNS{
+		header: header,
+	}, nil
+}
+
+func init() {
+	common.Must(common.RegisterConfig((*Config)(nil), NewDNS))
+}