Cloak/internal/common/tls.go

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package common
import (
"encoding/binary"
"io"
"net"
"time"
)
const (
VersionTLS11 = 0x0301
VersionTLS13 = 0x0303
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recordLayerLength = 5
Handshake = 22
ApplicationData = 23
)
func AddRecordLayer(input []byte, typ byte, ver uint16) []byte {
length := make([]byte, 2)
binary.BigEndian.PutUint16(length, uint16(len(input)))
ret := make([]byte, 5+len(input))
ret[0] = typ
binary.BigEndian.PutUint16(ret[1:3], ver)
copy(ret[3:5], length)
copy(ret[5:], input)
return ret
}
type TLSConn struct {
net.Conn
}
func (tls *TLSConn) LocalAddr() net.Addr {
return tls.Conn.LocalAddr()
}
func (tls *TLSConn) RemoteAddr() net.Addr {
return tls.Conn.RemoteAddr()
}
func (tls *TLSConn) SetDeadline(t time.Time) error {
return tls.Conn.SetDeadline(t)
}
func (tls *TLSConn) SetReadDeadline(t time.Time) error {
return tls.Conn.SetReadDeadline(t)
}
func (tls *TLSConn) SetWriteDeadline(t time.Time) error {
return tls.Conn.SetWriteDeadline(t)
}
func (tls *TLSConn) Read(buffer []byte) (n int, err error) {
// TCP is a stream. Multiple TLS messages can arrive at the same time,
// a single message can also be segmented due to MTU of the IP layer.
// This function guareentees a single TLS message to be read and everything
// else is left in the buffer.
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_, err = io.ReadFull(tls.Conn, buffer[:recordLayerLength])
if err != nil {
return
}
dataLength := int(binary.BigEndian.Uint16(buffer[3:5]))
if dataLength > len(buffer) {
err = io.ErrShortBuffer
return
}
return io.ReadFull(tls.Conn, buffer[:dataLength])
}
func (tls *TLSConn) Write(in []byte) (n int, err error) {
// TODO: write record layer directly first?
toWrite := AddRecordLayer(in, ApplicationData, VersionTLS13)
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n, err = tls.Conn.Write(toWrite)
return n - recordLayerLength, err
}
func (tls *TLSConn) Close() error {
return tls.Conn.Close()
}