Ganliber / microTFTP

Micro TFTP Client & Server implemented by Linux C

TFTP Protocol

Official : tftp protocol

TFTP Packets

Opcode

          opcode  operation
            1     Read request (RRQ)
            2     Write request (WRQ)
            3     Data (DATA)
            4     Acknowledgment (ACK)
            5     Error (ERROR)

Datagram Structure

Order of Headers

                                                  2 bytes
    ----------------------------------------------------------
   |  Local Medium  |  Internet  |  Datagram  |  TFTP Opcode  |
    ----------------------------------------------------------

TFTP Formats

   Type   Op #     Format without header

          2 bytes    string   1 byte     string   1 byte
          -----------------------------------------------
   RRQ/  | 01/02 |  Filename  |   0  |    Mode    |   0  |
   WRQ    -----------------------------------------------
          2 bytes    2 bytes       n bytes
          ---------------------------------
   DATA  | 03    |   Block #  |    Data    |
          ---------------------------------
          2 bytes    2 bytes
          --------------------
   ACK   | 04    |   Block #  |
          --------------------
          2 bytes  2 bytes        string    1 byte
          ----------------------------------------
   ERROR | 05    |  ErrorCode |   ErrMsg   |   0  |
          ----------------------------------------

Error Codes

   Value     Meaning

   0         Not defined, see error message (if any).
   1         File not found.
   2         Access violation.
   3         Disk full or allocation exceeded.
   4         Illegal TFTP operation.
   5         Unknown transfer ID.
   6         File already exists.
   7         No such user.