golang实现keepalived

type VRRPHeader struct {
    ProtoVersion   byte
    Type           byte
    VirtualRouter  byte
    Priority       byte
    CountIPAddr    uint8
    CountAuth      uint8
    AdvertInterval uint16
    Checksum       uint16
    VrrpIpAddr     net.IP
    MasterIpAddr   net.IP
    AuthType       uint8
    AuthDataField  []byte
}

type VRRPMessage struct {
    Header VRRPHeader
    Body   []byte
}

const (
    VRRP_VERSION = 3
    VRRP_TYPE = 1
    VRRP_GROUP_ID = 1
    VRRP_PRIORITY = 100
    ADVERT_INTERVAL = 1
)

func CreateVRRPMessage() VRRPMessage {
    var message VRRPMessage
    message.Header.ProtoVersion = VRRP_VERSION
    message.Header.Type = VRRP_TYPE
    message.Header.VirtualRouter = VRRP_GROUP_ID
    message.Header.Priority = VRRP_PRIORITY
    message.Header.CountIPAddr = 1
    message.Header.CountAuth = 0
    message.Header.AdvertInterval = ADVERT_INTERVAL
    message.Header.Checksum = 0
    message.Header.VrrpIpAddr = net.IPv4(192, 168, 1, 1)
    message.Header.MasterIpAddr = net.IPv4(10, 0, 0, 1)
    message.Header.AuthType = 0

    buf := new(bytes.Buffer)
    binary.Write(buf, binary.BigEndian, message.Header)
    message.Body = buf.Bytes()
    crc := crc32.ChecksumIEEE(message.Body)
    binary.BigEndian.PutUint16(message.Body[6:8], uint16(crc))
    return message
}

func SendVRRPMessage(iface *net.Interface, destIP net.IP, message VRRPMessage) error {
    Socket, err := net.DialUDP("udp4", nil, &net.UDPAddr{IP: destIP, Port: 112})
    if err != nil {
        return err
    }
    defer socket.Close()

    addr, err := net.ResolveUDPAddr("udp", iface.Name)
    if err != nil {
        return err
    }

    err = syscall.Bind(socket.FileDescriptor(), addr)
    if err != nil {
        return err
    }

    socket.WriteToUDP(message.Body, &net.UDPAddr{IP: destIP, Port: 112})
    return nil
}

func main() {
    iface, err := net.InterfaceByName("eth0")
    if err != nil {
        fmt.Println("Error getting interface: ", err)
        return
    }

    destIP := net.IPv4(224, 0, 0, 18)

    for {
        message := CreateVRRPMessage()
        err := SendVRRPMessage(iface, destIP, message)
        if err != nil {
            fmt.Println("Error sending VRRP message: ", err)
        }
        time.Sleep(time.Duration(message.Header.AdvertInterval) * time.Second)
    }
}