Intel Extensible Firmware Interface - Manual (Page 659)

Protocols — Network Support
Version 1.10 12/01/02 15-53
This function can take up to 10 seconds to timeout and return control to the caller. If the TFTP
sequence does not complete,
EFI_TIMEOUT will be returned.
If the Callback Protocol does not return
EFI_PXE_BASE_CODE_CALLBACK_STATUS_CONTINUE , then the TFTP sequence is stopped
and EFI_ABORTED will be returned.
The format of the data returned from a TFTP read directory operation is a null-terminated filename
followed by a null-terminated information string, of the form “size year-month-day
hour:minute:second” (i.e. %d %d-%d-%d %d:%d:%f - note that the seconds field can be a decimal
number), where the date and time are UTC. For an MTFTP read directory command, there is
additionally a null-terminated multicast IP address preceding the filename of the form
%d.%d.%d.%d for IP v4 (TBD for IP v6). The final entry is itself null-terminated, so that the final
information string is terminated with two null octets.
Status Codes Returned
EFI_SUCCESS The TFTP/MTFTP operation was completed.
EFI_NOT_STARTED The PXE Base Code Protocol is in the stopped state.
EFI_INVALID_PARAMETER One of the parameters is not valid.
EFI_DEVICE_ERROR The network device encountered an error during this operation.
EFI_BUFFER_TOO_SMALL The buffer is not large enough to complete the read operation.
EFI_ABORTED The callback function aborted the TFTP/MTFTP operation.
EFI_TIMEOUT The TFTP/MTFTP operation timed out.
EFI_TFTP_ERROR The TFTP/MTFTP operation generated an error.