add initial service definition

pkg/definitions/service.go

@@ -0,0 +1,49 @@
+package definitions
+
+import "encoding/json"
+
+type Service struct {
+	Type       ServiceType `json:"type"`
+	Comment    string      `json:"comment,omitempty"`
+	SPortStart *uint32     `json:"sport_start,omitempty"`
+	SPortEnd   *uint32     `json:"sport_end,omitempty"`
+	DPortStart *uint32     `json:"dport_start,omitempty"`
+	DPortEnd   *uint32     `json:"dport_end,omitempty"`
+	ICMPCode   *uint32     `json:"icmp_code,omitempty"`
+}
+
+type ServiceType int
+
+const (
+	TCP ServiceType = iota
+	UDP
+	TCPUDP
+	ICMP
+)
+
+func (t ServiceType) String() string {
+	return [...]string{"tcp", "udp", "tcpudp", "icmp"}[t]
+}
+
+func (t *ServiceType) FromString(input string) ServiceType {
+	return map[string]ServiceType{
+		"tcp":    TCP,
+		"udp":    UDP,
+		"tcpudp": TCPUDP,
+		"icmp":   ICMP,
+	}[input]
+}
+
+func (t ServiceType) MarshalJSON() ([]byte, error) {
+	return json.Marshal(t.String())
+}
+
+func (t *ServiceType) UnmarshalJSON(b []byte) error {
+	var s string
+	err := json.Unmarshal(b, &s)
+	if err != nil {
+		return err
+	}
+	*t = t.FromString(s)
+	return nil
+}