Open System Services Programmer's Guide

Header_Data
Table 43 shows the structure of the header data sent from the OSS name server to the OSS SEEP.
The header is always present. When the OSS SEEP responds to an event request, it is expected
to alter these fields in the header data:
• Error
• Status
• SubjectData
• MessageData
NOTE: The field names in the following table are pseudonyms and do not exactly match the
names as specified in the DDL. For variable names, see the DDL output. The DDL is located in the
ZOSS.SEEPDDL file.
Table 43 Header_Data
DescriptionTypeField
The base from which the offsets to other data areas are
calculated. Base indicates the allocation of a placeholder,
INT[0:-1]Base
not data. It is used for reference for all offsets and
VAR-STRING fields within the messages.
An enumeration describing the type of Message_Data in
the message. The valid types are HANDSHAKE (for
short (2 bytes)EventType
handshake message) and OSS_ACCESS_CONTROL (for
authorization request).
The version of this message structure. The OSS SEEP is
responsible for checking the message version and
short (2 bytes)MsgVersion
rejecting any message it does not recognize. The rejection
is returned in the Error field of this header. Currently, this
value is 1.
The oldest version of the message that must be supported
by the OSS SEEP in order to interpret this message.
Currently, this value is 1.
short (2 bytes)MinMsgVersion
The byte offset to the subject data associated with this
message. It must be an even number.
short (2 bytes)SubjectData
Set to 0 in the handshake request and in the response
from the OSS SEEP.
The byte offset to the message data associated with this
message. It must be an even number.
short (2 bytes)MessageData
Set to 0 in the handshake request and in the response
from the OSS SEEP.
Subsystem ID of the sender in standard SSID format. This
is the OSS SSID).
SSID-STRUCTSSID
The time the message is sent, in Greenwich mean time
(GMT).
Fixed (8 bytes)Timestamp
The system number of the system originating the request.int (4 bytes)OriginalSystemNumber
Unused in OSS SEEP.int (4 bytes)Filler
A return value that indicates the OSS SEEP’s response to
the message. The value is always 0 when the message is
sent. Valid return values are as follows:
short (2 bytes)Error
0 = OK – The request was successfully processed and a
valid status is returned
280 Managing OSS Security