This appendix provides a technical description of how C masking routines for ODBC work; particular detail is given to the
meaning of the fields within the Data Masking interface.
For ODBC extension,
Data Express provides two types of masking routines: standard masking and extended masking. Standard masking routines have limited capabilities
as opposed to extended masking routines, meaning that they mask only one value, are not based on dependencies, and use only
the source value and its length. Also, when two or more source values are related, the masking of one could depend on the
other.
Note: This limitation does not apply to the Oracle extension because its masking routines exist as part of a working chain rather
than within a DLL. Hence, the routine itself has information about all columns.
The extended masking routines, provided in
Data Express starting with Update 17, have the same interface as the COBOL masking routine.
Interface Details
The interface for the extended C masking routines allows you to decide exactly what kind of masking to perform, based on
additional parameters including:
- UR-RECORD
- String-based variable that contains all record values.
- Source value parameters
- A structure, containing all metadata of the source value like type, length, int, dec, position (the starting position in the
UR-RECORD), including the value itself.
- Output values structure
- A structure that stores the output value and the masking type, which can be either by a single masked value or extracted from
the UR-RECORD.
For complete information, see
Masking Routines in
Getting Started with Distributed Data Stores
Examples
The following examples show the complexity of extended masking as opposed to standard masking:
- Standard Masking
-
char* UDCNAMC(char *szValue, unsigned int *nLength)
- Extended Masking
-
char * UDCNAMC(char *action, char *fileinfo, char *record,
struct fldstruct *chgparams_fstruct, struct fldodata *chgparams_odata,
struct fldoutput *chgparams_out)
- action
- INIT,
EXEC, or
LAST. For more information, see
Modification Exit Routines Parameters in your
Data Masking Guide.
- fileinfo
- Used only in z/OS.
- record
- UR-RECORD
- fldstruct
- The structure containing the input source information.
struct fldstruct
{
unsigned char f_inpval[UR_INP_VAL_LEN];
int f_posn;
int f_len;
unsigned char f_fldtype;
short f_inttype;
short f_dectype;
unsigned char f_sign;
unsigned char f_null;
unsigned char f_varchar;
unsigned char f_inull;
short f_otherfld;
} ;
- f_inpval
- The source value.
- f_posn
- Its position in the UR-RECORD.
- f_len
- The column length.
- f_fldtype
- The column type.
- f_inttype
- int type.
- f_dectype
- dec type.
- f_sign
- Whether value is signed, or unsigned.
- f_null
- Whether column is nullable, or not.
- f_varchar
- Whether varchar is signed, or unsigned.
- f_inull
- Whether the value is NULL, or not.
- f_otherfld
- Used only in z/OS.
- fldodata
- Unused structure in the distributed engine.
struct fldodata
{
unsigned char oth_filename[UR_FILE_NAME_LEN];
unsigned char oth_filetype[4];
unsigned char oth_inpval[UR_INP_VAL_LEN];
short oth_posn; /*short*/
short oth_len; /*short*/
unsigned char oth_fldtype;
short oth_inttype; /*short*/
short oth_dectype; /*short*/
unsigned char oth_sign;
unsigned char oth_null;
unsigned char oth_varchar;
unsigned char oth_inull;
short oth_otherfld;
} ;
- fldoutput
- Output structure that is being returned to the DE engine.
struct fldoutput
{
char out_outval[UR_INP_VAL_LEN];
char out_fldtype;
short out_fldlen; /*short*/
short out_inttype; /*short*/
short out_dectype; /*short*/
char out_fldsign;
char out_rtncode[2];
char out_msgcode[7]; /*7*/
char out_msgparm[UR_OUT_MSGPARM_LEN];
char out_type;
char out_descr[80];
};
- out_outval
- The masked value.
- out_fldtype
- The output column type.
- out_fldlen
- The output column length.
- out_inttype
- The output
int type.
- out_dectype
- The output
dec type.
- out_fldsign
- The output value sign.
- out_rtncode
- The return code of the masking routine. If the masking is successful, the return code is " " (space).
- out_msgcode
- Used only in z/OS
- out_msgparm
- Used only in z/OS
- out_type
- Identifies the output type. One of:
| R
|
The out_outval value is ignored and what is in the UR-RECORD is inserted in the target environment.
|
| F
|
The masked value used is the one stored in out_outval.
|
- out_desrc
- Used only in z/OS
*
#define UR_INP_VAL_LEN 256
#define UR_RECORD_LEN 32760
#define UR_FILE_NAME_LEN 128
#define UR_OUT_MSGPARM_LEN 128