serve.go

func (b *backend) handle(c1 *tls.Conn, c *net.TCPConn) {
	c2, err := net.DialTCP("tcp", nil, b.addr)
	if err != nil {
		c1.Close()
		return
	}
	go func() {
		err := io.Copy(c2, c1)
		if err != nil {
			log.Print(err)
		}
		c.CloseWrite()
		c1.CloseRead()
	}()
	err := io.Copy(c1, c2)
	if err != nil {
		log.Print(err)
	}
	c.CloseWrite()
	c2.CloseRead()
}