recvfrom.c

  if (!buf)
    {
      err = EINVAL;
      goto errout;
    }

  /* Get the underlying socket structure */
  /* Verify that the sockfd corresponds to valid, allocated socket */

  psock = sockfd_socket(sockfd);
  if (!psock || psock->s_crefs <= 0)
    {
      err = EBADF;
      goto errout;
    }

  /* If a 'from' address has been provided, verify that it is large
   * enough to hold this address family.
   */

  if (from)
    {
#ifdef CONFIG_NET_IPv6
      if (*fromlen < sizeof(struct sockaddr_in6))
#else
      if (*fromlen < sizeof(struct sockaddr_in))
#endif
        {
          err = EINVAL;
          goto errout;
        }
    }

  /* Set the socket state to receiving */

  psock->s_flags = _SS_SETSTATE(psock->s_flags, _SF_RECV);

  /* Perform the TCP/IP or UDP recv() operation */

#if defined(CONFIG_NET_UDP) && defined(CONFIG_NET_TCP)
  if (psock->s_type == SOCK_STREAM)
    {
      ret = tcp_recvfrom(psock, buf, len, infrom);
    }
  else
    {
      ret = udp_recvfrom(psock, buf, len, infrom);
    }
#elif defined(CONFIG_NET_TCP)
  ret = tcp_recvfrom(psock, buf, len, infrom);
#elif defined(CONFIG_NET_UDP)
  ret = udp_recvfrom(psock, buf, len, infrom);
#else
  ret = -ENOSYS;
#endif

  /* Set the socket state to idle */

  psock->s_flags = _SS_SETSTATE(psock->s_flags, _SF_IDLE);

  /* Handle returned errors */

  if (ret < 0)
    {
      err = -ret;
      goto errout;
    }

  /* Success return */

  return ret;

errout:
  *get_errno_ptr() = err;
  return ERROR;
}

#endif /* CONFIG_NET */