Inside Macintosh: Networking /

Chapter 5 - AppleTalk Data Stream Protocol (ADSP)

This chapter describes the AppleTalk Data Stream Protocol (ADSP) that you use to establish a session to exchange data between two network processes or applications in which both parties have equal control over the communication. You should read this chapter if you want to write an application that supports the exchange of more than a small amount of data between two parties who each can both send and receive streams of data.

This chapter also describes the AppleTalk Secure Data Stream Protocol (ASDSP), a secure version of ADSP, that allows users of your application to communicate over an ADSP session after the users' identities have been authenticated. Users can then exchange encrypted data over the session. For your application to use ASDSP, the system on which it runs must have the AppleTalk Open Collaboration Environment (AOCE) software installed and must have access to an AOCE server. To use ASDSP, you must also use the Authentication Manager, which is a component of the AOCE software. For information on the Authentication Manager, refer to Inside Macintosh: AOCE Application Programming Interfaces.

ASDSP enhances ADSP with authentication and encryption features. When this chapter discusses components of ADSP, such as connection ends and connection listeners, you can assume that the information also applies to ASDSP. The sections in this chapter that discuss ASDSP describe any specific differences between it and the standard version of ADSP. To use ASDSP, you should be familiar with ADSP.

For an overview of ADSP and how it fits within the AppleTalk protocol stack, read the chapter "Introduction to AppleTalk" in this book, which also introduces and defines some of the terminology used in this chapter. For a complete explanation of the ADSP specification, see Inside AppleTalk, second edition.

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Chapter Contents

About ADSP

Connections, Connection Ends, and Connection States

Connection Listeners

Reliable Delivery of Data

Unsolicited ADSP Events

About ASDSP

The Authentication Process

The Data Encryption Feature

Using ADSP

Allocating Memory for ADSP

Creating and Using a Connection Control Block

Opening and Maintaining an ADSP Connection

Creating and Using a Connection Listener

Writing a User Routine for Connection Events

Using ASDSP

Opening a Secure Connection

From the Initiator's End

From the Recipient End

Sending Encrypted Data Across a Secure Connection

ADSP Reference

Data Structures

The ADSP Connection Control Block Record

The Address Block Record

The DSP Parameter Block

The ASDSP Parameter Block

The TRSecureParams Record

Routines

DESCRIPTION

Establishing and Terminating an ADSP Connection

Establishing and Terminating an ADSP Connection Listener

Maintaining an ADSP Connection and Using It to Exchange Data

Summary of ADSP

Pascal Summary

Constants

Data Types

The ADSP Connection Control Block Record

The Address Block Record

The DSP Parameter Block

The ASDSP Parameter Block

The TRSecureParams Record

C Summary

Constants

Data Types

The ADSP Connection Control Block Record

The Address Block Record

Parameter Block for dspInit and dspCLInit

Parameter Block for dspOpen, dspCLListen, and dspCLDeny

Parameter Block for dspClose and dspRemove

Parameter Block for dspStatus

Parameter Block for dspRead and dspWrite

Parameter Block for dspAttention

Parameter Block for dspOptions

Parameter Block for dspNewCID

The DSP Parameter Block

The ASDSP Parameter Block

Assembly-Language Summary

Constants

ADSP Queue Element Equates and Sizes

Command Codes

Open Connection Modes

Connection States

Client Event Flags (Bit-Mask)

Miscellaneous Equates

ASDSP Encrypt and End-of-Message Flags and Masks

Data Structures

ADSP Connection Control Block Data Structure

DPS Parameter Block Common Fields for ADSP and ASDSP

dspInit and dspCLInit Parameter Variant

dspOptions Parameter Variant

dspOpen, dspCLListen, and dspCLDeny Parameter Variant

sdspOpen Parameter Variant

dspNewCID Parameter Variant

dspClose, dspRemove, and dspCLRemove Parameter Variant

dspStatus Parameter Variant

dspRead and dspWrite Parameter Variant

dspAttention and dspReset Parameter Variant

Result Codes