Natural Remote Procedure Call (RPC) is available as a separate subcomponent of Natural. It has its own version number. This measure takes into account that Natural RPC is a cross-platform component and makes it possible to provide new Natural RPC versions independent of new Natural versions for the various platforms supported.
As of Version 6.3 of Natural Remote Procedure Call (RPC), the enhancements listed in this document are available. The following topics are covered:
The Natural RPC documentation has been restructured and revised completely, also taking into account the new features that are now available with EntireX Communicator (EntireX Broker).
Information on prerequisites and restrictions that you should observe before you start to implement or modify a Natural RPC environment has been summarized in the following sections of the Natural Remote Procedure Call (RPC) documentation:
With Natural RPC Version 5.1.1 (and below), an RPC built-in conversion
from EBCDIC to ASCII and vice versa took place if the EntireX attrribute
TRANSLATION or
CONVERSION was missing in the Broker attribute
file and the encoding of the client data had to be translated to the required
encoding of the server platform.
The RPC built-in conversion from EBCDIC to ASCII and vice versa has
been removed. The conversion of client data from EBCDIC to ASCII and vice versa
is already part of the EntireX functionality. In addition, the EntireX
conversion is more versatile than the RPC built-in conversion. Specify the
EntireX attributes TRANSLATION or
CONVERSION in the Broker attribute file to
ensure an appropriate conversion.
With Natural RPC Version 5.1.1 (and below), the library
SYSRPC is implicitly set as a steplib when the service is accessed
on the client side.
The library SYSRPC is no longer set as a steplib during
execution of a remote CALLNAT request. This is to improve the
performance and to avoid that an old service directory in the library
SYSRPC is accidentally accessed. The SYSRPC utility
places the service directory in the current user library instead of library
SYSRPC in the FNAT system file. Therefore, the
library SYSRPC should not contain any user-specific information,
including the service directory.
If you want to continue to use a service directory that has been placed
in library SYSRPC before, you have the following choices:
Move the service directory from the library SYSRPC to
the client library.
Move the service directory from the library SYSRPC to
the library SYSTEM in the FUSER system file.
Define the library SYSRPC as an additional steplib using
Natural Security.
Use the application programming interface USR3025N in
the library SYSEXT to set the library SYSRPC as an
additional steplib in an environment without Natural Security.
The new EntireX RPC protocol RPC2000 introduces the following new features that are supported by Natural RPC Version 6.3:
The new header layout of the RPC2000 protocol has removed all length restrictions for names. However, Natural-specific names such as library names, program names and user IDs remain limited to 8 characters (this feature requires that RPC2000 is enabled).
Base 64 encoding is used for marshalling of binary data. This saves up to 30 percent space in the send/receive buffer (this feature requires that RPC2000 is enabled).
If the parameter data area (PDA) contains arrays of groups, the physical field sequence of a PDA may be different on the client and server sides if the PDA contains arrays of groups. With Natural RPC Version 6.3, the group structure of a PDA may be kept when an RPC server is called by a Natural client. This is to ensure the same physical field sequence in the PDA for both the client and the server.
X-arrays are supported in the parameter list of a remote
CALLNAT execution. The server may increase or decrease the number
of occurrences.
Restrictions:
In case of a multidimensional array, all dimensions of the array must be extensible.
The lower bound must not be extensible, that is only extensible upper bounds are allowed.
Variables of format U (Unicode data in UTF-16) are supported in the
parameter list of a remote CALLNAT execution. The
variables may either be fixed length variables or dynamic variables.
If U data is sent from a platform with big endian encoding to a platform with little endian encoding or vice versa, the encoding is adapted so that it conforms with the encoding on the receiving platform. For example, when U data in little endian encoding arrives on a big endian platform, this data is converted to big endian encoding before it is handed over to the program. When this data is sent back, it is converted back to little endian encoding.
Optional parameters (nX
notation in the CALLNAT statement) are supported in the parameter
list of a remote CALLNAT execution.
With Natural RPC Version 6.3, the following features available with ACI Version 6 and ACI version 7 are supported:
Data compression to compress the send/receive buffer on client and server side. This feature reduces the amount of data that is to be transferred from client to server and vice versa. To use this feature, ACI Version 7 is required.
Data that is exchanged between client and server may be encrypted for reasons of data security. To use this feature, ACI Version 6 is required.
To unbundle the client and the server environment, an application
programming interface (API) is provided. This API (USR4008)
enables the client to set the library in which the CALLNAT request
is to be executed on the server side. The LOGON option must be set
to ON to use this feature.
A new application programming interface (USR4009) is
provided to enable the client to set EntireX-specific parameters for RPC
request execution.
The new application programming interface USR2075N enables
you to terminate the EntireX Broker Service from within your application. See
Terminating a Natural
RPC Server in the Natural Remote Procedure Call
(RPC) documentation.
With Natural RPC Version 6.3, two optional user exits are introduced. These exits are called by the Natural RPC server at certain events and must be implemented by the user as a subprogram. The following two user exits have been introduced:
A before-service-execution user exit that is called after the data is
unmarshalled and before the service (the remote CALLNAT) is
executed.
An after-service-execution user exit that is called on return from
the service (the remote CALLNAT) and before the data is
marshalled.
The new parameter CPRPC is used to specify the
name of the code page used by the EntireX Broker. CPRPC
is applied to the Natural RPC facility when the transport protocol ACI (that is
EntireX Broker) is used. See also Migrating Applications to Version
6.3.
The new parameter SRVWAIT is used to specify the
number of seconds the server is to wait for an RPC client request.
With Natural RPC Version 6.3, additional information is logged in the Natural RPC server trace file to aid in error diagnostics.
For better error diagnostics, the server will provide additional status information. An application programming interface (API) is provided to return this information to the client.
Status information includes:
the STEPLIB chain,
the Natural buffer pool that is used,
important Natural profile parameter settings (FNAT,
FUSER, RPC parameters, ...).
Several administrative database calls, that have been issued after processing of the client RPC request has been completed, have been eliminated with Natural RPC Version 6.3. This improves the performance of the RPC server especially for those requests which generate only a small workload.
The Natural RPC server has been enhanced by the possibility to change
the Natural Security (NSC) password on the FSEC by a remote
procedure call.
The new application programming interface USR2074N allows
a Natural RPC client which is running in a non-NSC environment to change the
NSC password on the FSEC via a remote procedure call. It is no
longer required for the client to use a terminal emulation to change the
password on the Natural logon screen.
Similar interfaces are provided by EntireX to enable an EntireX RPC client to change his NSC password.
The sample callers USR1071P, USR2071P and
USR2072P of the application programming interfaces
USR1071N, USR2071N and USR2072N allow
the use of case-sensitive user IDs and passwords.
By default, user IDs and passwords are translated into upper case for compatibility reasons.
To prevent password attacks if a Natural RPC server is running under Natural Security, each invalid logon attempt is now recorded on the FSEC. If the limit for logon attempts is reached for a user, this user is locked and any further logon attempt (valid or invalid) is rejected. The counter for the logon attempts is reset for a specific user after a successful logon of this user.
Please note that this feature leads to the intended incompatibility that a user must be unlocked after the limit of logon attempts has been reached. In previous versions, the number of attempts was unlimited.
Refer to RPC Server Session Options in Library and User Preset Values in the Natural Security documentation for more details.
If your application has once issued an EntireX Broker logon using the
application programming interface USR2071N, a new logon is
enforced after a timeout. In previous versions, the behavior after a timeout
depends on the AUTOLOGON setting in the EntireX Broker attribute
file.
With AUTOLOGON=YES an implicit logon is issued.
With AUTOLOGON=NO a new logon is enforced.
This feature avoids problems with external security systems such as
RACF if AUTOLOGON=YES is specified but an explicit logon is
required.
If the profile parameter
ACIVERS is set to 8, the
Natural RPC issues a KERNELVERS call to get the
correct value for the ACI field KERNELSECURITY. In this case, it
is no longer required to perform the special installation steps to install the
EntireX Broker stubs for EntireX Security (install the secuexit module).
This enhancement applies to the Natural RPC server as well as to the
Natural RPC client. In case of a Natural RPC client, the
KERNELVERS call is done as part of the EntireX logon
using the application programming interface
USR2071N.
The profile parameter DFS has been enhanced to
prevent the Natural RPC from accessing and using a service directory. This
avoids that a service directory has to be created before Natural RPC can be
used. Using this feature will result in a reduction of administrative overhead
and a corresponding performance enhancement.
The TRACE profile parameter has
been enhanced by an option to write a trace entry only if an error has
occurred. This enables you to analyze errors on the Natural RPC server side
without the need to have the Natural RPC trace permanently turned on.
The EntireX ACI Version 9 is now supported by
ACIVERS. This allows you to
enable the EntireX Broker stub to send additional environmental information
about client and server to the EntireX Broker.
The following Natural limits apply to the Natural RPC server:
LT - Limit for Processing Loops,
MAXCL - Maximum Number of Program Calls,
MADIO - Maximum DBMS Calls between Screen I/O
Operations.
This makes it difficult to enforce certain limits on every
CALLNAT request.
With Natural RPC Version 6.3, these limits are reset after each remote
CALLNAT execution to avoid unpredictable error situations when the
execution of a client request reaches one of the limits due to the processing
of a previous client.
The maximum length for node and server names in the sample callers
USR2007P and USR2071P of the
application programming
interfaces USR2007N and USR2071N has been
increased from 8 to 32.
The following changes/enhancements have been provided in the
SYSRPC utility:
For stubless RPC calls, the required space for the send/receive buffers can be calculated without generating a stub to allow the user to determine the space requirements.
For stubs with the default field attribute M (inout), the stub generation can now also be executed in command mode with wildcard notation for a set of stubs. A stub can be generated in batch mode on the basis of an existing subprogram. In this case, all field attributes will be M.
When a stub is generated, a comment is added to the parameters to indicate whether a parameter is an input or an output parameter.
The format buffer length limit is dynamically calculated depending on the buffer space currently used for data.
It is now possible to generate stubs that contain dynamic variables in their parameter data area (PDA). The Stub Generation screen has been adapted accordingly.
It is now possible to enter field levels and groups on the Stub Generation screen. The definition of groups is required to access certain EntireX RPC servers.
Only contiguous groups are supported.
It is now possible to generate stubs that contain X-arrays in their parameter data area (PDA). The Stub Generation screen has been adapted accordingly.
In the Stub Generation screen (which is used to
enter the parameter definitions that are used in the stub subprogram), you can
now specify a maximum of 5000 parameters. See
Specifying Parameters in the
SYSRPC section of the Tools and Utilities
documentation.
It is now possible to generate stubs that contain format U variables in their parameter data area (PDA). The Stub Generation screen has been adapted accordingly.
To reduce the size of the service directory and to enhance its readability, it will be possible to use wildcard notation to specify subprogram names.
To ease the inspection of a large service directory, a search function is provided for subprogram names.
It is now possible to terminate all server tasks associated with a given EntireX Broker service. See Terminating a Server in the SYSRPC part of the Utility documentation. In previous versions, it was only possible to terminate a single server.
With Natural RPC Version 6.3, an application programming interface (API) is provided to enable access to information stored in the local directory located on the remote server.
A comment is added to the service directory containing the Natural version that was used to generate the service directory. In addition, a copyright notice of Software AG will be contained in the service directory.
In some places, the documentation set for Natural for OpenVMS mentions features which are (currently) not supported with Natural for OpenVMS. Such features are:
The Integrated Authentication Framework (IAF), which is an optional feature that can be used on the Natural RPC server side and which is controlled by Natural Security, is not supported on OpenVMS platforms. Therefore, the following section in the Natural Remote Procedure Call (RPC) documentation does not apply on OpenVMS: Using the Integrated Authentication Framework.
