function custom_rewrite_rules() {
    [add_rewrite_rule](http://codex.wordpress.org/Function_Reference/add_rewrite_rule)(
        '^product/(.*)/?$', 
        'index.php?pagename=product&name=$matches[1]',
        'top'
    );
}
[add_action](http://codex.wordpress.org/Function_Reference/add_action)( '[init](http://codex.wordpress.org/Plugin_API/Action_Reference/init)', 'custom_rewrite_rules' );

function custom_register_rewrite_tag() {
    add_rewrite_tag( '%name%', '(.*)');
}
[add_action](http://codex.wordpress.org/Function_Reference/add_action)( '[init](http://codex.wordpress.org/Plugin_API/Action_Reference/init)', 'custom_register_rewrite_tag');