HP HP-UX 11i Reference Guide

ACC Programmer’s Reference Guide

Edition 9

HP 9000 Networking

Manufacturing Part Number: Z7487-90002

E0400

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First Edition Dec 1992 Release 1.0 Second Edition Mar 1994 Release 2.1

Third Edition April 1995 Release 2.2 Fourth Edition September 1995 Release B.02.20 (HP-UX 10.01) Fifth Edition March 1996 Release B.02.21 (HP-UX 10.01) Sixth Edition January 1997 Release B.02.30 Seventh Edition August 1997 Release B.02.39 (HP-UX 10.10)

Release B.02.40 (HP-UX 10.20)

Eighth Edition October 1998 Release B.03.01 (HP-UX 11.0)

Ninth Edition April 2000 Release B.03.10 (HP-UX 11.0)

Related Documentation

The documentation available for the Multiprotocol ACC family of products includes the following hardware and software manuals:

Hardware Manuals

• 8 Channel HP-PB ACC Multiplexer Hardware Installation and Reference Manual

• 8 Channel EISA ACC Multiplexer Hardware Installation and Reference Manual

• 8 Channel PCI ACC Multiplexer Hardware Installation and Reference Manual

• 2 Channel (HP-PB) ACC Multiplexer Hardware Installation and Reference Manual

• 4-Chan. T1/E1 (HP-PB) ACC Multiplexer Hardware Installation and Reference Manual

Software Manuals

• ACC Installation and Configuration Guide

• ACC Utilities Reference Guide

• ACC Programmer’s Reference Guide

• ACC Error Guide

• HDLC Frame Protocol User’s Guide

• ACC X.25 Protocol User’s Guide

• ACC X.25/ISDN Data Analyzer User’s Guide

• ACC HDLC/LAP-B (ABM) Protocol User’s Guide

• ACC HDLC/LAP-D Protocol User’s Guide

• HDLC-NRM (SDLC) Protocol User’s Guide

• X.25/ACC Installation and Configuration Guide

• X.25/ACC Update Guide

• X.25/9000 User’s Guide

• X.25/9000 Programmer’s Guide

Contents

1. ZCOM Subsystem

Introduction................................................12

ZCOMSoftwareOverview ....................................13

ZCOMConcepts.............................................17

ProgramZLUs............................................19

TerminalZLUs............................................19

UserInterface..............................................21

References.................................................22

2. ZCOM Message Handling

Overview ..................................................24

ZLUDefinition..............................................25

ProgramZLUs............................................25

TerminalZLUs............................................25

MappedZLUs.............................................26

MessageQueuing............................................27

Priorities...................................................29

Multiplexing................................................30

OutboundMultiplexing.....................................31

InboundMultiplexing.......................................32

TerminalState..............................................34

ErrorHandling .............................................35

Contents

3. ZCOM Tables and Data Structures

Introduction...............................................38

MemoryOrganization.......................................39

Differencesin32-bitand64-bitDataStructures..................40

ZCOMHeaderStructure.....................................42

NodeEntriesTable..........................................54

ZLUTables................................................ 57

IndividualZLUEntries ....................................57

LogicalTerminalTables...................................... 60

PhysicalTerminalTables..................................... 66

InterfaceTable.............................................75

ResponseRecords...........................................94

QueueHeader.............................................. 97

DataBufferPool...........................................102

OrganizationofBufferPool ................................ 102

MessageHeader........................................... 107

MessageHeader(zmhd_type)............................... 107

MessageIDHeader(zmid_type) ............................ 108

MessageRequestHeader(zmrq_type) .......................111

SystemEventMessage(zevent_type)........................113

ZCOMKernelData ........................................118

NCARD ................................................ 118

HPATable..............................................118

SYS....................................................122

HP ....................................................126

LINFO.................................................126

Contents

4. ZCOM C I/F Library Routines

Introduction...............................................130

Initializationcall .........................................131

Interfaceconfigurationcall.................................131

ZLUconfigurationcalls....................................131

Datastorageallocationcalls................................131

ZLUinformationcalls .....................................132

ZLUDefinition...........................................134

ManPages................................................135

GETDEVICE(3X)..........................................136

LTFIND(3X) ..............................................140

LTQDGET(3X) ............................................144

LTQDPUT(3X) ............................................147

MAKEZLUNAME(3X)......................................150

PTFIND(3X)..............................................153

ZCLOS(3X)...............................................157

ZCNTL(3X)...............................................160

ZCOMERROR(3X).........................................167

ZCOMLNAME(3X).........................................169

ZCOMLOG(3X)............................................171

ZCOMSTATUS(3X).........................................176

ZCONFIG(3X).............................................178

ZEVENT_RCVR (3X). . . . ....................................209

ZGET_SHRCVR_LIST (3X) . . . . . . . . . . . . . . ....................214

ZINFO(3X) ...............................................217

Contents

ZINIT(3X) ...............................................221

ZLTMG(3X).............................................. 224

ZLTMX(3X) ..............................................227

ZLTQUEUE(3X) ..........................................230

ZLTSTORE(3X)...........................................234

ZLTUP(3X)...............................................237

ZLUOPEN(3X)............................................ 240

ZMAPR(3X)..............................................243

ZNAME(3X)..............................................245

ZOPEN(3X).............................................. 248

ZPEEK(3X) ..............................................252

zport(3X) ................................................254

ZPTUP(3X)...............................................262

ZQMVE(3X) .............................................264

ZQSZE(3X)...............................................266

ZREAD (3X) . . ............................................ 269

ZRNTIMER(3X)........................................... 275

ZSEND(3X) .............................................. 278

ZSETQL(3X) ............................................. 288

ZSET_RCVR(3X)..........................................291

ZTIMR(3X)...............................................295

1 ZCOM Subsystem

ZCOM Subsystem

Introduction

The ZCOM Subsystem consists of software and firmware t hat provide the base set of features for the ACC Product family. It consists of:

• HP-UX interface drivers that communicate with the ACC Mux cards

• the ZCOM Mux Kernel which is an operating system that is

downloaded to the ACC Mux cards

• a set of daemon and utility programs that provide and facilitate

access to the ZCOM Subsystem

• a library of routines t hat provides a comprehensive user interface t o

the ZCOM Subsystem.

The ZCOM Subsystem also provides a powerful framework for experienced data communication programmers to develop customized protocols for specialized data communication applications.

This document describes the programmatic interface to the ZCOM Subsystem. It describes the ZCOM Subsystem tables, buffers, and routines, and how they are used to achieve program-to-device and program-to-program communication. It als o contains information required when writing application programs to take advantage of ACC product features, such as:

• remote node access

Thisfeatureallowsprogrammaticrequeststoberoutedtoeithera Mux card that is connected to the system on which the request is made, or to a program or Mux card on a remote system.

• dual interface Mux panel configurations

This feature allows two systems to connect to a single Mux panel.

• multiple protocol support

• true multi-thread programming support

• 64-bit programming support

12 Chapter1

ZCOM Subsystem

ZCOM Software Overview

Figure 1-1 on page 14 presents an architectural overview of the ZCOM Subsystem.

The ZCOM application interface provides low level access to the ZCOM Subsystem. Application programs make requests via the ZCOM library routines which are then communicated to the firmware on the ACC Mux card via the HP-UX drivers.

The firmware which runs on the ACC Mux card includes the ZCOM Mux kernel software plus ZCOM protocol modules. The ZCOM protocol modules provide the protocol specific firmware that runs on the ACC Mux card

Note that the highlighted area in Figure 1-1 shows which software components are provided by the base ZCOM Subsystem. Only protocol modules used for loopback testing, and for monitoring the health of the ACC Mux card and panel are provided with the base ZCOM Subsystem. Protocol specific modules, such as X.25, are added to the ZCOM Subsystem as separate products. The Protocol User’s Guides provided with these products must be used in conjunction with this Programmer’s Reference Guide when writing ZCOM application program

Chapter 1 13

ZCOM Subsystem

ZCOM Software Overview

Figure 1-1 Overview of ZCOM Software Structure

Application

or Utility

Program

X.25 TCP/IP

X.25 Level3 Prog. Accs.

Application

or Utility

Program

Other high

level

protocol

ZCOM HP-UX Drivers (LDM/DAM)

ZCOM Mux Kernel

......

Application

or Utility

Program

Low level

ZCOM I/F

HP9000

System

ACC Mux I/F

ZCOM

Protocol

Module

(X.25)

ZCOM

Protocol

Module

Mux datacomm interface to network

14 Chapter1

ZCOM

Protocol

Module

......

ZCOM

Protocol

Module

Figure 1-2 presents another view of the ZCOM Subsystem which includes the relationships between the various components of the ZCOM Subsystem:

Figure 1-2 ZCOM Subsystem Components

C Application

Program

ZCOM Subsystem

ZCOM Software Overview

ZCOM initialization and Mux download by ZMON

zmasterd

zmon

zmlog

Error log Files

The ZCOM Subsystem is initialized by the zmon daemon which reads a memory image file and downloads appropriate firmware to the ACC Mux interface cards. The memory image file is created by running the ttgen utility on an ASCII configuration file which contains information such as what protocol will be used on the various ports of the ACC Mux cards, and protocol specific configuration.

ZCOM I/F Library

ZCOM HP-UX Drivers

ACC I/F

Card

ACC I/F

Card

ACC I/F

Card

zterm

Utility

ZCOM Kernel

Tables & Buffers

...

ACC I/F

Card

Chapter 1 15

ZCOM Subsystem

ZCOM Software Overview

The zmlog program is used to log error messages generated by the programs and daemons of the ZCOM Subsystem. The zmasterd daemon is used to facilitate starting up and shutting down the daemons in the ZCOM Subsystem, and to automatically recover from daemon failures.

Application programs make calls to the routines in the ZCOM application interface. The same requests that can be made programmatically can also be made interactively by using the zterm program

16 Chapter1

ZCOM Subsystem

ZCOM Concepts

Throughout this manual, references are made to terminal ZLU or just terminal. This does not mean a physical terminal device type but is a

generic term that can refer to any kind of physical or logical entity. Examples of physical entities are printers, an HDLC link, terminals, etc. Examples of logical entities might be an X.25 Permanent or Switched Virtual Circuit.

In the ZCOM Subsystem, messages are sent directly from sender to receiver (where the receiver is another program or a terminal ZLU). They are routed using a pointer called a ‘ZLU’ which stands for ‘ZCOM Logical Unit’. ZCOM uses t he ZLU for its addressing mechanism. A ZLU may represent a terminal (for instance, an X.25 virtual circuit) or an application program. Messages are sent to and received by ZLUs.

Figure 1-3 on page 18

shows a sample set of program and terminal ZLUs,

and their interaction with each other and a Mux card:

Chapter 1 17

ZCOM Subsystem

ZCOM Concepts

Figure 1-3 Definition and Features of ZLUs

Terminal 2

Terminal 1

Terminal

ZLU=57

Program

ZLU=502

Application Program A

Mux card

Terminal

ZLU=231

Program

ZLU=500

Application Program B

Terminal 3

Terminal

ZLU=101

To communicate to another program or to a terminal, a program uses ZCOM library calls to write to a program or terminal ZLU. Each program ZLU points to a queue that contains all messages, including timeout and statusmessages, that were deliveredto the program ZLU. These pointers are maintained automatically by the ZCOM Subsystem. When a message is sent to a ZLU, the data is moved to a system buffer first and the address of the message is moved to the attached input queue.

18 Chapter1

ZCOM Subsystem

ZCOM Concepts

Program ZLUs

Each program may open one or more program ZLUs which provides an input message queue to that program. Think of a program’s input message queue as a m ailbox where messages can be delivered. All messages delivered are queued at the end of the input queue for a program in the order in which they were received. Note that the message is not actually delivered to the program, but simply placed into the input queue. The program must issue a ZCOM library call to retrieve the messages one-by-one from the input queue. The method used to cause a message to be placed into a program’s input queue will be different depending on whether the message was created by another program or a physical/logical device.

If a message is sent (generated) by another program, then the sending program must specify the ZLU of the program’s input queue to place the message into. The receiving program need not do anything for the message to be successfully delivered to their mail box (program input queue).

However, when a message is generated by a terminal ZLU, any program that wishes to receive messages from that device (terminal ZLU) must inform the ZCOM Subsystem first. The program should issue a ZCOM call (zset_rcvr) to tell the ZCOM Subsystem that all data coming from the specified terminal ZLU should be delivered to its input queue. Whenever data arrives from the device, it will be placed into the input queues of all programs that have requested this data.

Terminal ZLUs

Terminal ZLUs represent a physical or logical device and do not have input queues of their own. Any data coming from a terminal ZLU will be delivered to the input queues of all applications that have requested it. If there is no application interested in receiving the data, then the data is thrown away and a message is logged to that effect.

TerminalZLUs do however have three different output (transmit) queues. When a program sends data to a terminal ZLU,it can select one of three queues to place that data on. Each queue represents a different level of priority. The Express Queue is used for extremely high-priority protocol dependent requests. The High-Priority Queue is used for high priority data and the Low-Priority Queue is used for low priority data. When a message is generated by an application, the buffers involved are queued to the selected transmit queue and the ZCOM driver is notified.

Chapter 1 19

ZCOM Subsystem

ZCOM Concepts

The driver is then responsible for handling the message. Messages on the express q ueue are sent before those on the high priority queue which are sent before those on the low priority queue.

Because the ZCOM Subsystem itself takes responsibility for the delivery of messages, the sending program is able to specify a number of options when it passes the message to the system. These options include:

• Continue execution whether the message is sent successfully or not.

• Continue execution but report any error status (status messages are

queued to the ZLU of the calling program).

• Continueexecution; a definite response will be queued to the program

ZLU when the send has completed.

• Suspend execution until the send has completed (i.e.,

acknowledgment that the message was transmitted).

On completion, the message buffer may also be passed back to the sending application program if required.

Each message on the ZLU has a ‘type’ attribute so that the program reading the ZLU is able to differentiate between status messages, timeout messages and data messages from terminals or other programs.

20 Chapter1

ZCOM Subsystem

User Interface

The interface between the application programs and the ZCOM Subsystem is through the ZCOM ‘C’ Application Programming Interface (API) library. The functions provided by this library are documented in Chapter 4 , “ZCOM C I/F Library Routines.” All functions within the library are thread-safe and can be used in multi-threaded programs. Both 32-bit and 64-bit applications are supported.

The interactive program ZTERM gives the user access to all the ZCOM routines and can be used to test programs or terminals by sending and receiving messages between them. The program ZSCAN allows the programmer to display the contents of the ZCOM memory areas.

Chapter 1 21

ZCOM Subsystem

References

The following manuals should be referred to when using the ZCOM application interface:

• ACC Installation and Configuration Guide

• ACC Utilities Reference Guide The manuals corresponding to the protocol being used should also be

referred to:

• ACC X.25 Protocol User’s Guide

• ACC HDLC/LAP-B Protocol User’s Guide

• ACC HDLC/LAP-D Protocol User’s Guide

• ACC HDLC/NRM Protocol User’s Guide Documentation recommended for protocol developers includes:

• Z16C35 CMOS ISCC Technical Manual

(Zilog P/N DC-8286-01)

• Z80180/Z180 MPU Microprocessor Unit Tech Manual

(Zilog P/N DC-826-03)

• Z80 CPU TechnicalManual

(Zilog P/N DC-0029-04)

• SCC Technical Manual

(Zilog P/N DC-8293-01)

22 Chapter1

2 ZCOM Message Handling

ZCOM Message Handling

Overview

ZCOM message handling is achieved through logical constructs called ZLUs which maintain queues for messages to terminals and programs. The terminal ZLUs are either defined a t ZCOM configuration time using ttgen, or can be created programmatically using the Dynamic System Configuration functions; the program ZLUs are allocated dynamically from a pool of ZLUs when requested.

24 Chapter2

ZCOM Message Handling

ZLU Definition

There are three types of ZLUs. These are:

•Program

• Terminal (or remote device via a communication link)

•Mapped

Program ZLUs

A Program ZLU may be either a primary ZLU or an auxiliary ZLU. All programs using ZCOM must have a primary ZLU defined. Other ZLUs may then be defined as auxiliary if required. If a message is sent to another program, then the destination ZLU is the other program’s primary or auxiliary ZLU.

Terminal ZLUs

Terminal ZLUs are used to direct messages to terminals. Before a program can receive messages from a terminal, a program must set itself up as receiver for that particular terminal’s ZLU (using the zset_rcvr routine call). Any number of programs can be set up as a receiver for a given terminal at any one time. It is possible, of course, to set up a program to route messages to other programs from the terminal ZL U.

NOTE Terminal ZLU is a generic term. The actual physical entity associated

with a terminal ZLU is dependent on the particular protocol being used. For example, with a TTY protocol a Terminal ZLU would be associated withaphysicalterminalorterminallikedevice.However,witha protocol such as X.25, a terminal ZLU might represent a virtual circuit or the HDLC line (X.25 level 2).

Chapter 2 25

ZCOM Message Handling

ZLU Definition

Mapped ZLUs

AllmessagesaddressedtoaparticularZLUwillberedirectedtothe alternate ZLU specified in the zmapr routine call if the original ZLU has been mapped to a different ZLU. One use of mapped ZLUs is for providing high availability systems. For example, if a hardware failure was detected in one of the ACC Mux cards, the application could map all of the ZLUs associated with the failed card to a spare unused card in the system.

26 Chapter2

ZCOM Message Handling

Message Queuing

Each program ZLU (either primary or auxiliary) has a single input queue on which messages are received and read on a first-in-first-out basis.Because the ZLU is the input queuing mechanismfor timeoutsand statuses,as well a s for data messages, all programs should request (through the zopen routine) at least one program ZLU before using the other ZCOM calls.

The ztimr routine may be used to enable or disable the timer on a program ZLU. When enabled, a timeout message is added to the input queue of the ZLU every n seconds (n being specified as a parameterto the ztimr call). If there are already 10 or more messages on the queue, no timer message is queued. Timer processing stops when ZTIMER and ZCLOCK are reset to zero via the ztimr routine (a zero “time” value).

The application program uses the zread routinetoreadmessagesfrom the input queue. All response and status messages are written to the primary program ZLU. Data messages can be written to eit her the primary or auxiliary program ZLUs.

When a zsend routine call is executed, the message to be sent is moved to the ZCOM kernel buffer which is queued to the ZLU to which the messagewassent.Themessageisaddedtotheendofthequeueforthe specified ZLU.

Figure 2-1 Program Message Queueing

Application A

zread

Chapter 2 27

Primary Program

Input Queue

Points to the Input Queue

MSGMSG

ZCOM Message Handling

Message Queuing

Queues for terminal ZLUs are located in the physical terminal tables in the ZCOM memory area as shown in Figure 2-2. The physical terminal tables (one per terminal) maintain four queues for each terminal.

Figure 2-2 Physical Terminal Table

Physical Terminal Table

Express Queue

High Priority Queue

Low Priority Queue

Unacknowledged Queue

The driver reads messages first from the express queue until there are no remainingexpress queue messages, then from the high priorityqueue until there are no high priority messages, at which stage the low priority queue is read. Any further additions to the higher priority queues will be read before the driver continues with the lower priority queues. When the interface card is ready to accept messages, t he driver moves the message to the unacknowledged queue and transfers the message to the interface card (through the unacknowledged queue). Both the interface card and the driver use DMA (Direct Memory Access) hardware to transfer the messages. If the number of buffers on the unacknowledged queue is less than the limit specified to TTGEN, more messages will be transferred, otherwise the transfer will be suspended until some outstanding messages are acknowledged.

Once the interface card has transmitted the message and has responded with a definite status, the driver passes the status (if requested to do so) back to the calling program. If the calling program also requires the message buffer to be sent back with the status response, it is picked up from the unacknowledged queue. Once the driver has passed the message to the program, the message is removed from the unacknowledged queue.

Messages in the unacknowledged queues for each terminal are also used in a Mux restart: the messages are movedback to the high priority queue to b e resent. The size of the unacknowledged queue is configurable in the TTGEN configuration file.

28 Chapter2

ZCOM Message Handling

Priorities

Priorities only apply to messages that are destined for terminals. MessagestoprogramZLUsaresimplyaddedtotheendoftheinput queue for that ZLU.

Messages destined for terminal ZLUs may have either express, high or low priority. The priority for a message is determined by bits ZCOM_ZSEND_LPRand ZCOM_ZSEND_XPS of the mode parameter, in the zsend and zcntl routine calls. If the ZCOM_ZSEND_XPS bit is set, then the message is queued on the express queue in the physical terminal table for that terminal ZLU. If the ZCOM_ZSEND_LPR bit is set, then the message is queued on the low priority queue in the physical terminal table for that terminal ZLU. If neither bit is set, then the message is queued on the high priority queue. This enables background tasks to be sent at lower priorities, without impacting any on-line throughput.

The driver reads the information from the terminal tables, looking at the high priority queue for each terminal and sending the message at the head of that queue. The driver only checks the low priority queue if there are no messages on the high priority queue. This means that any message on the high priority queue will be sent first.

NOTE The Express Queue should be reserved for Protocol Control events, such

as, interrupts or resets. Normally, data should not be sent using the Express Queue.

Chapter 2 29

ZCOM Message Handling

Multiplexing

The multiplexing feature of ZCOM allows more than one logical terminal to be mapped to a single physical terminal. This mechanism i s implemented in ZCOM by allowing messages to and from a terminal ZLU to be intercepted by a program (which is able to alter the data content, e.g., adding or removing headers) and then forwarded on to the destination physical terminal or its receiver program.

Some fields in the logical terminal table and in the physical terminal table are mentioned in the following descriptions; more information on these fields can be found in the logical terminal table and the physical terminal table information in the section on Tables and Data Structures.

The outbound and the inbound multiplexing are separate, so although in most situations the multiplexing program will perform both functions, it is possible to perform only inbound multiplexing or only outbound multiplexing in any program.

The ltflag field of the logical terminal table (zltt_type) contains two flag bits ZCOM_LTFLAG_OMX and ZCOM_LTFLAG_IMX, which indicate whether messages to or from the logical terminal respectively, are to be handled by a multiplexing program. These bits are set by TTGEN according to the device type.

When more than one logical terminal is mapped to a single physical terminal, the ltgzlk field (<zltt_type>.ltgzlk) linkage forms a circular list of terminals in the same multiplexed group (i.e., mapped to the same physical terminal). The ltqzlk field contains the ZLU number (16-bit) of the next terminal in the group. For a non-multiplexing terminal, this field contains the ZLU number of the current terminal (i.e., pointing back to itself, a special case for circular list).

30 Chapter2

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