Exit points for controlling TFTP server

An exit point is a specific point in the Trivial File Transfer Protocol (TFTP) program where control can pass to an exit program. An exit program is a program to which the exit point passes control. With the use of exit programs, the experienced programmer can create customized processing when an application is running.

If the TFTP server finds a program registered to one of the exit points for the system, it calls that program using parameters that are defined by the exit point.

For each exit point, there is an associated programming interface, called an exit point interface. The exit point uses this interface to pass information between the TFTP application and the exit program. Each exit point has a unique name. Each exit point interface has an exit point format name that defines how information is passed between the TFTP application and the customer-written exit program.

Different exit points can share the same exit point interface. When this is the case, multiple exit points can call a single exit program.

To allow the exit programs to work properly, you must install and register your exit point programs. If your programs are no longer needed, you must properly remove the exit point programs to prevent their future functioning.

Exit point performance

The following table lists exit points that give you additional control over the TFTP server.

Table 1. TFTP exit point and format
TCP/IP exit point Application Exit point format Brief description
QIBM_QTOD_SERVER_REQ TFTP VLRQ0100 The TCP/IP request validation exit point provides additional control for restricting an operation.
Notes:
  • The same interface format is used for request validation for the File Transfer Protocol (FTP) client, FTP server, REXEC server, and TFTP server. This allows the use of one exit program for request validation of any combination of these applications.
  • The same interface format is used for server log-on processing for the FTP server and TFTP server applications. This allows the use of one exit program to process log-on requests for both of these applications.