User Exit 5

Purpose

This exit point allows execution of a user‑developed exit routine that provides additional security checking before a transfer takes place. The exit is used with the system security option chosen in the CA XCOM Data Transport Default Options Table's SECURITY parameter (for example, IBM RACF, CA Top Secret, or CA ACF2).

Module Name and Entry Point

The default module name and entry point for this exit is XCOMEX05. The default module name can be overridden by specifying the load-module name in the Default Options.

The exit is entered for TYPE=EXECUTE and TYPE=SCHEDULE transfers. The exit is entered after session establishment.

This exit must be reentrant.

How to Enable

Specify EXIT05=YES | Load-module name in the Default Options to enable this exit.

Required DSECT

SECDSECT is the required DSECT.

Calling Module and Entry Sequence

This exit is called by the module XCOMFILE, which in turn is called either by XCOMJOB or XCOMXFER.

For SNA transfers, the SECLUN field of SECDSECT contains the target LU for TYPE=EXECUTE (XCOMJOB) transfers and TYPE=SCHEDULE transfers queued to the CA XCOM Data Transport for z/OS started task (XCOMXFER). For IP transfers, the SECLUN field of the SECDSECT contains the hexadecimal representation of the partner's IP address if TCPLUSEC=binary is specified in the CA XCOM Data Transport default options table. The exit is also entered when XCOMJOB is executed with TYPE=SCHEDULE. In this case, SECLUN contains the APPLID of the CA XCOM Data Transport for z/OS started task. This entry sequence allows you to determine whether the transfer should be queued for execution. If the target LU must be tested for a TYPE=SCHEDULE transfer, the test must be deferred until the exit is called by XCOMXFER.

The following table summarizes how the exit is given control:

EXEC PGM=	PARM=	XCOMEX05 Entry Sequence	SECLUN Contents
XCOMJOB	TYPE=EXECUTE	XCOMJOB ® XCOMFILE ® XCOMEX05	REMOTE LU OR IP ADDRESS (hex)
XCOMJOB	TYPE=SCHEDULE	XCOMJOB ® XCOMFILE ® XCOMEX05	XCOMAPPL (that is, the APPLID of the CA XCOM Data Transport for z/OS server)
XCOMXFER	N/A	XCOMXFER ® XCOMFILE ® XCOMEX05	REMOTE LU OR IP ADDRESS (hex)

The CSAJOBF field in the CSA (CSADSECT) identifies which entry sequence (XCOMJOB or XCOMXFER) was used while the NSABATF field in the NSA (NSADSECT) identifies the transfer as being of type TYPE=EXECUTE or TYPE=SCHEDULE:

Field	EQU	Field Contents	Description
CSAJOBF	CSAJOBJ	Character 'J'	XCOMEX05 entered via XCOMJOB
	CSAJOBX	Character 'X'	XCOMEX05 entered via XCOMXFER
NSABATF	NSABATE	Character 'E'	TYPE=EXECUTE transfer
	NSABATS	Character 'S'	TYPE=SCHEDULE transfer

Note: CSADSECT and NSADSECT are distributed in CA XCOM Data Transport's macro library, CAI.CBXGMAC. CSADSECT is pointed to by NSA@CSA.

Entry Method

This exit is a branch entry.

Addressing Mode at Entry

The addressing mode at entry is 31. XCOMEX05 must have a linkedit mode of reentrant.

Registers at Entry

The following registers are available at entry:

R0: Undefined
R1: Address of SECDSECT
R2: Undefined
R3: Address of NSADSECT
R4 to R12: Undefined
R13: Address of register save area
R14: Return address
R15: Entry point address

Note: Addressability to CA XCOM Data Transport's CSA as mapped by the CSADSECT can be obtained by loading NSA@CSA to the register used to map the CSA.

Registers at Exit

The following registers are available at exit:

R0 to R14: Undefined
R15: Return code

Valid Return Code

The only valid return code is 0 for a normal return.

Note: The return code from the exit is passed in field SECRTNCD of the exit parameter list (which is mapped by the SECDSECT macro found in CAI.CBXGMAC).

Sample Program

The following is a sample program using this exit:

CAI.CBXGSAMP(XCOMEX05)