dns outbound proxy

common/protocol/dns/errors.generated.go

@@ -0,0 +1,9 @@
+package dns
+
+import "v2ray.com/core/common/errors"
+
+type errPathObjHolder struct{}
+
+func newError(values ...interface{}) *errors.Error {
+	return errors.New(values...).WithPathObj(errPathObjHolder{})
+}

common/protocol/dns/io.go

@@ -1,11 +1,13 @@
 package dns
 
 import (
+	"encoding/binary"
 	"sync"
 
 	"golang.org/x/net/dns/dnsmessage"
 	"v2ray.com/core/common"
 	"v2ray.com/core/common/buf"
+	"v2ray.com/core/common/serial"
 )
 
 func PackMessage(msg *dnsmessage.Message) (*buf.Buffer, error) {
@@ -75,3 +77,67 @@ func (r *UDPReader) Close() error {
 
 	return common.Close(r.Reader)
 }
+
+type TCPReader struct {
+	reader *buf.BufferedReader
+}
+
+func NewTCPReader(reader buf.Reader) *TCPReader {
+	return &TCPReader{
+		reader: &buf.BufferedReader{
+			Reader: reader,
+		},
+	}
+}
+
+func (r *TCPReader) ReadMessage() (*buf.Buffer, error) {
+	size, err := serial.ReadUint16(r.reader)
+	if err != nil {
+		return nil, err
+	}
+	if size > buf.Size {
+		return nil, newError("message size too large: ", size)
+	}
+	b := buf.New()
+	if _, err := b.ReadFullFrom(r.reader, int32(size)); err != nil {
+		return nil, err
+	}
+	return b, nil
+}
+
+func (r *TCPReader) Interrupt() {
+	common.Interrupt(r.reader)
+}
+
+func (r *TCPReader) Close() error {
+	return common.Close(r.reader)
+}
+
+type MessageWriter interface {
+	WriteMessage(msg *buf.Buffer) error
+}
+
+type UDPWriter struct {
+	buf.Writer
+}
+
+func (w *UDPWriter) WriteMessage(b *buf.Buffer) error {
+	return w.WriteMultiBuffer(buf.MultiBuffer{b})
+}
+
+type TCPWriter struct {
+	buf.Writer
+}
+
+func (w *TCPWriter) WriteMessage(b *buf.Buffer) error {
+	if b.IsEmpty() {
+		return nil
+	}
+
+	mb := make(buf.MultiBuffer, 0, 2)
+
+	size := buf.New()
+	binary.BigEndian.PutUint16(size.Extend(2), uint16(b.Len()))
+	mb = append(mb, size, b)
+	return w.WriteMultiBuffer(mb)
+}