<?xml version="1.0"?>
<xs:schema xmlns:xs="http://www.w3.org/2001/XMLSchema"
elementFormDefault="qualified">

<xs:element name="service">
  <xs:complexType>
    <xs:sequence>
      <xs:element name="short" type="xs:string" minOccurs="0"/>
      <xs:element name="description" type="xs:string" minOccurs="0"/>
      <xs:element name="include" type="includetype" minOccurs="0" maxOccurs="unbounded"/>
      <xs:element name="port" type="porttype" minOccurs="0" maxOccurs="unbounded"/>
      <xs:element name="source-port" type="porttype" minOccurs="0" maxOccurs="unbounded"/>
      <xs:element name="protocol" type="prototype" minOccurs="0" maxOccurs="unbounded"/>
      <xs:element name="destination" type="desttype" minOccurs="0"/>
      <xs:element name="module" type="nametype" minOccurs="0" maxOccurs="unbounded"/>
      <xs:element name="helper" type="helpertype" minOccurs="0"/>
    </xs:sequence>
    <xs:attribute name="version" type="xs:string"/>
  </xs:complexType>
</xs:element>

<xs:complexType name="nametype">
  <xs:attribute name="name" type="xs:string" use="required"/>
</xs:complexType>

<xs:complexType name="prototype">
  <xs:attribute name="value" type="xs:string" use="required"/>
</xs:complexType>

<xs:complexType name="porttype">
  <xs:attribute name="port" type="porttyperestrict" use="required"/>
  <xs:attribute name="protocol" type="xs:string" use="required"/>
</xs:complexType>

<xs:simpleType name="porttyperestrict">
  <xs:restriction base="xs:string">
    <xs:pattern value="([0-9]+(\-[0-9]+)?)?"/>
  </xs:restriction>
</xs:simpleType>

<xs:complexType name="desttype">
  <xs:attribute name="ipv4" type="ipv4addrtype"/>
  <xs:attribute name="ipv6" type="ipv6addrtype"/>
</xs:complexType>

<xs:simpleType name="ipv4addrtype">
  <xs:restriction base="xs:string">
    <xs:pattern value="([0-9]{1,3}\.){3}[0-9]{1,3}(/[0-9]{1,2})?"/>
  </xs:restriction>
</xs:simpleType>

<xs:simpleType name="ipv6addrtype">
  <xs:restriction base="xs:string">
    <!-- very rough RE -->
    <xs:pattern value="[0-9A-Fa-f:]{3,39}(/[0-9]{1,3})?"/>
  </xs:restriction>
</xs:simpleType>

<xs:complexType name="includetype">
  <xs:attribute name="service" type="xs:string" use="required"/>
</xs:complexType>

<xs:complexType name="helpertype">
  <xs:attribute name="name" type="xs:string" use="required"/>
</xs:complexType>

</xs:schema>