sernum_buffer_t
sernum_buffer_t ccb_DataSN_buf;
sernum_buffer_t c_StatSN_buf;
sn_empty(sernum_buffer_t *buf)
void init_sernum(sernum_buffer_t *);
int add_sernum(sernum_buffer_t *, uint32_t);
uint32_t ack_sernum(sernum_buffer_t *, uint32_t);
init_sernum(sernum_buffer_t *buff)
add_sernum(sernum_buffer_t *buff, uint32_t num)
ack_sernum(sernum_buffer_t *buff, uint32_t num)