type ChildContext struct {
	// PID of the child, can be used for ns-entering to the child namespaces.
	PID int
	// IP of the tap device
	IP net.IP
}

type ChildDriver interface {
	RunChildDriver(opaque map[string]string, quit <-chan struct{}) error
}

type Manager interface {
	AddPort(ctx context.Context, spec Spec) (*Status, error)
	ListPorts(ctx context.Context) ([]Status, error)
	RemovePort(ctx context.Context, id int) error
}

type ParentDriver interface {
	Manager
	// OpaqueForChild typically consists of socket path
	// for controlling child from parent
	OpaqueForChild() map[string]string
	// RunParentDriver signals initComplete when ParentDriver is ready to
	// serve as Manager.
	// RunParentDriver blocks until quit is signaled.
	//
	// ChildContext is optional.
	RunParentDriver(initComplete chan struct{}, quit <-chan struct{}, cctx *ChildContext) error
}

type Spec struct {
	Proto      string `json:"proto,omitempty"`    // either "tcp" or "udp". in future "sctp" will be supported as well.
	ParentIP   string `json:"parentIP,omitempty"` // IPv4 address. can be empty (0.0.0.0).
	ParentPort int    `json:"parentPort,omitempty"`
	ChildPort  int    `json:"childPort,omitempty"`
}

type Status struct {
	ID   int  `json:"id"`
	Spec Spec `json:"spec"`
}