Add shadowtls v2 support

transport/shadowtls/conn.go

@@ -0,0 +1,96 @@
+package shadowtls
+
+import (
+	"encoding/binary"
+	"io"
+	"net"
+
+	"github.com/sagernet/sing-box/common/tls"
+	"github.com/sagernet/sing/common"
+	"github.com/sagernet/sing/common/buf"
+	"github.com/sagernet/sing/common/bufio"
+	N "github.com/sagernet/sing/common/network"
+)
+
+var (
+	_ N.ExtendedConn     = (*Conn)(nil)
+	_ N.VectorisedWriter = (*Conn)(nil)
+)
+
+type Conn struct {
+	N.ExtendedConn
+	writer        N.VectorisedWriter
+	readRemaining int
+}
+
+func NewConn(conn net.Conn) *Conn {
+	return &Conn{
+		ExtendedConn: bufio.NewExtendedConn(conn),
+		writer:       bufio.NewVectorisedWriter(conn),
+	}
+}
+
+func (c *Conn) Read(p []byte) (n int, err error) {
+	if c.readRemaining > 0 {
+		if len(p) > c.readRemaining {
+			p = p[:c.readRemaining]
+		}
+		n, err = c.ExtendedConn.Read(p)
+		c.readRemaining -= n
+		return
+	}
+	var tlsHeader [5]byte
+	_, err = io.ReadFull(c.ExtendedConn, common.Dup(tlsHeader[:]))
+	if err != nil {
+		return
+	}
+	length := int(binary.BigEndian.Uint16(tlsHeader[3:5]))
+	readLen := len(p)
+	if readLen > length {
+		readLen = length
+	}
+	n, err = c.ExtendedConn.Read(p[:readLen])
+	if err != nil {
+		return
+	}
+	c.readRemaining = length - n
+	return
+}
+
+func (c *Conn) Write(p []byte) (n int, err error) {
+	var header [5]byte
+	defer common.KeepAlive(header)
+	header[0] = 23
+	for len(p) > 16384 {
+		binary.BigEndian.PutUint16(header[1:3], tls.VersionTLS12)
+		binary.BigEndian.PutUint16(header[3:5], uint16(16384))
+		_, err = bufio.WriteVectorised(c.writer, [][]byte{common.Dup(header[:]), p[:16384]})
+		common.KeepAlive(header)
+		if err != nil {
+			return
+		}
+		n += 16384
+		p = p[16384:]
+	}
+	binary.BigEndian.PutUint16(header[1:3], tls.VersionTLS12)
+	binary.BigEndian.PutUint16(header[3:5], uint16(len(p)))
+	_, err = bufio.WriteVectorised(c.writer, [][]byte{common.Dup(header[:]), p})
+	if err == nil {
+		n += len(p)
+	}
+	return
+}
+
+func (c *Conn) WriteVectorised(buffers []*buf.Buffer) error {
+	var header [5]byte
+	defer common.KeepAlive(header)
+	header[0] = 23
+	dataLen := buf.LenMulti(buffers)
+	binary.BigEndian.PutUint16(header[1:3], tls.VersionTLS12)
+	binary.BigEndian.PutUint16(header[3:5], uint16(dataLen))
+	return c.writer.WriteVectorised(append([]*buf.Buffer{buf.As(header[:])}, buffers...))
+}
+
+func (c *Conn) Upstream() any {
+	return c.ExtendedConn
+}