create-ip-address-field-cmb2.php

<?php

/**
 * Render the new field in the admin area.
 *
 * @param  object $field             The current CMB2_Field object.
 * @param  string $escaped_value     The value of this field passed through the escaping filter.
 * @param  int    $object_id         The id of the object you are working with.
 * @param  string $object_type       The type of object you are working with.
 * @param  object $field_type_object This is an instance of the CMB2_Types object.
 * @return void
 */
function cmb2_render_callback_for_ip_address( $field, $escaped_value, $object_id, $object_type, $field_type_object ) {
	echo $field_type_object->input( array( 'type' => 'text' ) );
}
add_action( 'cmb2_render_ip_address', 'cmb2_render_callback_for_ip_address', 10, 5 );


/**
 * Sanitize the input for the IP address field type
 *
 * @param  null   $override_value Sanitization override value to return.
 * @param  string $value          The actual field value.
 * @return string                 The sanitized IP address.
 */
function cmb2_sanitize_ip_address_callback( $override_value, $value ) {
	if ( ! filter_var( $value, FILTER_VALIDATE_IP ) ) {
		$value = '';
	}
	return $value;
}
add_filter( 'cmb2_sanitize_ip_address', 'cmb2_sanitize_ip_address_callback', 10, 2 );