const (
	// FlagPersistent specify IPVS service session affinity
	FlagPersistent = 0x1
	// FlagHashed specify IPVS service hash flag
	FlagHashed = 0x2
)

const (
	// KernelModuleIPVS is the kernel module "ip_vs"
	KernelModuleIPVS string = "ip_vs"
	// KernelModuleIPVSRR is the kernel module "ip_vs_rr"
	KernelModuleIPVSRR string = "ip_vs_rr"
	// KernelModuleIPVSWRR is the kernel module "ip_vs_wrr"
	KernelModuleIPVSWRR string = "ip_vs_wrr"
	// KernelModuleIPVSSH is the kernel module "ip_vs_sh"
	KernelModuleIPVSSH string = "ip_vs_sh"
	// KernelModuleNfConntrackIPV4 is the module "nf_conntrack_ipv4"
	KernelModuleNfConntrackIPV4 string = "nf_conntrack_ipv4"
	// KernelModuleNfConntrack is the kernel module "nf_conntrack"
	KernelModuleNfConntrack string = "nf_conntrack"
)

type Interface interface {
	// Flush clears all virtual servers in system. return occurred error immediately.
	Flush() error
	// AddVirtualServer creates the specified virtual server.
	AddVirtualServer(*VirtualServer) error
	// UpdateVirtualServer updates an already existing virtual server.  If the virtual server does not exist, return error.
	UpdateVirtualServer(*VirtualServer) error
	// DeleteVirtualServer deletes the specified virtual server.  If the virtual server does not exist, return error.
	DeleteVirtualServer(*VirtualServer) error
	// Given a partial virtual server, GetVirtualServer will return the specified virtual server information in the system.
	GetVirtualServer(*VirtualServer) (*VirtualServer, error)
	// GetVirtualServers lists all virtual servers in the system.
	GetVirtualServers() ([]*VirtualServer, error)
	// AddRealServer creates the specified real server for the specified virtual server.
	AddRealServer(*VirtualServer, *RealServer) error
	// GetRealServers returns all real servers for the specified virtual server.
	GetRealServers(*VirtualServer) ([]*RealServer, error)
	// DeleteRealServer deletes the specified real server from the specified virtual server.
	DeleteRealServer(*VirtualServer, *RealServer) error
	// UpdateRealServer updates the specified real server from the specified virtual server.
	UpdateRealServer(*VirtualServer, *RealServer) error
	// ConfigureTimeouts is the equivalent to running "ipvsadm --set" to configure tcp, tcpfin and udp timeouts
	ConfigureTimeouts(time.Duration, time.Duration, time.Duration) error
}

type RealServer struct {
	Address      net.IP
	Port         uint16
	Weight       int
	ActiveConn   int
	InactiveConn int
}

type ServiceFlags uint32

type VirtualServer struct {
	Address   net.IP
	Protocol  string
	Port      uint16
	Scheduler string
	Flags     ServiceFlags
	Timeout   uint32
}