uint32_t pktbuf_save(struct pktbuf *, const void *buffer, size_t buffer_size,
uint16_t in_port);
uint32_t pktbuf_get_null(void);
uint32_t pktbuf_save(struct pktbuf *, const void *buffer, size_t buffer_size,
uint16_t in_port);
uint32_t pktbuf_get_null(void);