Passing own struct into opengl es 2.0 shader

I want to try a lighting example from the book OpenGL ES 2.0 Programming Guide. In the shader they have made two structures.

struct directional_light   
{  

    vec3 direction; // normalized light direction in eye space  
    vec3 halfplane; // normalized half-plane vector  

    vec4 ambient_color;
    vec4 diffuse_color;
    vec4 specular_color;
};

struct material_properties 
{ 
    vec4 ambient_color; 
    vec4 diffuse_color; 
    vec4 specular_color; 
    float specular_exponent;
};

They have also made two uniforms, based on these structures.

uniform  material_properties u_material_properties;   
uniform directional_light u_directional_light;

The problem is, I do not know how to pass own structures into the actual shader.

I want to create the same structures in my main code and pass the objects into the shader. How is this possible?

Regards Niclas