How can i bind vertex data to GLSL in unity3D?

I make unity program with GLSL shader. I know how to use shader in openGL window programming, not unity.

in unity document, it say that 'use built-in attribute'. but it's so low version of GLSL. high version, use like this.

     layout(location = 0) in vec3 a_position;
     layout(location = 1) in vec3 a_normal;
     out vec3 v_position_EC;
     out vec3 v_normal_EC;

upper version don't support vayring variable and pre-defined variables.

if i set "#version 400", it can be complie. but any data goes.

i want convert this code to unity c# code.

  glGenBuffers(1, &rectangle_VBO);

  glBindBuffer(GL_ARRAY_BUFFER, rectangle_VBO);
  glBufferData(GL_ARRAY_BUFFER, sizeof(rectangle_vertices), &rectangle_vertices[0][0], GL_STATIC_DRAW);

  // Initialize vertex array object.
  glGenVertexArrays(1, &rectangle_VAO);
  glBindVertexArray(rectangle_VAO);

  glBindBuffer(GL_ARRAY_BUFFER, rectangle_VBO);
  glVertexAttribPointer(LOC_POSITION, 3, GL_FLOAT, GL_FALSE, 6 * sizeof(float), BUFFER_OFFSET(0));
  glEnableVertexAttribArray(0);
  glVertexAttribPointer(LOC_NORMAL, 3, GL_FLOAT, GL_FALSE, 6 * sizeof(float), BUFFER_OFFSET(3 * sizeof(float)));
   glEnableVertexAttribArray(1);

  glBindBuffer(GL_ARRAY_BUFFER, 0);
  glBindVertexArray(0);

I cant find any document for 'bind' data in unity. it's impossible? i want solution or say it cant.

I already complete convert to low version. but my boss want high version.... please help me!