Ejemplo n.º 1
0
void *read_serial_packet(serial_source src, int *len)
/* Effects: Read the serial source src. If a packet is available, return it.
     If in blocking mode and no packet is available, wait for one.
   Returns: the packet read (in newly allocated memory), with *len is
     set to the packet length, or NULL if no packet is yet available and
     the serial source is in non-blocking mode
*/
{
  read_and_process(src, TRUE);
  for (;;)
    {
      struct packet_list *entry;

      entry = pop_protocol_packet(src, P_PACKET_NO_ACK);
      if (entry)
	{
	  uint8_t *packet = entry->packet;

	  *len = entry->len;
	  free(entry);

	  return packet;
	}
      if (src->non_blocking && serial_source_empty(src))
	return NULL;
      source_wait(src, NULL);
      read_and_process(src, src->non_blocking);
    }
}
Ejemplo n.º 2
0
int write_serial_packet(serial_source src, const void *packet, int len)
/* Effects: writes len byte packet to serial source src
   Returns: 0 if packet successfully written, 1 if successfully written
     but not acknowledged, -1 otherwise
*/
{
  struct timeval deadline;

  src->send.seqno++;
  if (write_framed_packet(src, P_PACKET_ACK, src->send.seqno, packet, len) < 0)
    return -1;

  gettimeofday(&deadline, NULL);
  add_timeval(&deadline, ACK_TIMEOUT);
  for (;;) 
    {
      struct packet_list *entry;
      
      read_and_process(src);
      entry = pop_protocol_packet(src, P_ACK);
      if (entry)
	{
	  uint8_t acked = entry->packet[0];

	  free(entry->packet);
	  free(entry);
	  if (acked == src->send.seqno)
	    return 0;
	}
      else if (source_wait(src, &deadline) < 0)
	return 1;
    }
}