#define NF_OUT_DROP OFP_PORT_C(UINT16_MAX - 2)
struct netflow *netflow_create(void);
-void netflow_destroy(struct netflow *);
+struct netflow *netflow_ref(const struct netflow *);
+void netflow_unref(struct netflow *);
+bool netflow_exists(void);
+
int netflow_set_options(struct netflow *, const struct netflow_options *);
void netflow_expire(struct netflow *, struct flow *);