Sockets in C Sharp. Practical Guide for Programmers

188 Pages·2004·1.66 MB·English

by  David Makofske

TCP/IP Sockets in C#
Practical Guide for Programmers
The Morgan Kaufmann Practical Guides Series
Series Editor: Michael J. Donahoo
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pleasevisitourwebsiteathttp://www.mkp.com/practical
TCP/IP Sockets in C#
Practical Guide for Programmers
David B. Makofske
Akamai Technologies
Michael J. Donahoo
Baylor University
Kenneth L. Calvert
University of Kentucky
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Contents
Preface ix
1 Introduction 1
1.1 Networks,Packets,andProtocols 1
1.2 AboutAddresses 4
1.3 AboutNames 5
1.4 ClientsandServers 5
1.5 WhatIsaSocket? 6
1.6 Exercises 7
2 Basic Sockets 9
2.1 SocketAddresses 9
2.2 SocketImplementationin.NET 15
2.3 TCPSockets 16
2.4 UDPSockets 29
2.5 The.NETSocketClass 37
2.6 Exercises 57
3 Sending and Receiving Messages 59
3.1 EncodingInformation 61
3.2 ComposingI/OStreams 65
3.3 FramingandParsing 66
3.4 ImplementingWireFormatsinC# 70
3.5 WrappingUp 83
3.6 Exercises 84
vii
viii Contents ■
4 Beyond the Basics 85
4.1 NonblockingI/O 85
4.2 Multiplexing 95
4.3 Threads 99
4.4 AsynchronousI/O 117
4.5 MultipleRecipients 131
4.6 ClosingConnections 138
4.7 WrappingUp 145
4.8 Exercises 146
5 Under the Hood 147
5.1 BufferingandTCP 149
5.2 BufferDeadlock 152
5.3 PerformanceImplications 154
5.4 TCPSocketLifeCycle 155
5.5 DemultiplexingDemystified 165
5.6 Exercises 167
Appendix:HandlingSocketErrors 169
Bibliography 171
Index 173
Preface
Foryears,collegecoursesincomputernetworkingweretaughtwithlittleorno“handson”
experience. For various reasons, including some good ones, instructors approached the
principles of computer networking primarily through equations, analyses, and abstract
descriptionsofprotocolstacks.Textbooksmightincludecode,butitwasunconnectedto
anythingstudentscouldgettheirhandson. Perhapsinanidealworldthiswouldsuffice,
but we believe that students learn better when they can see (and then build) concrete
examplesoftheprinciplesatwork.Fortunately,suchexamplesaboundtoday.TheInternet
has become a part of everyday life, and access to its services is readily available to most
students(andtheirprograms).
The Berkeley Sockets interface, known universally as “sockets” for short, is the de
facto standard application programming interface (API) for networking, spanning a wide
range of operating systems. The sockets API was designed to provide generic access to
interprocess communication services that might be implemented by whatever protocols
were supported on a particular platform—IPX, Appletalk, TCP/IP, and so on. As a conse-
quence of this generic approach the sockets API may appear dauntingly complicated at
first. But, in fact, the basics of network programming using the Internet (TCP/IP) proto-
cols are not difficult. The sockets interface has been around for a long time—at least in
“Internettime”—butitislikelytoremainimportantfortheforeseeablefuture.
We have written this book to improve the support for socket-based programming
exercises in our own networking courses. Although some networking texts deal with net-
workprogramming,weknowofnonethatcoverTCP/IPsockets.Excellentreferencebooks
onTCP/IPsocketprogrammingexist,buttheyaretoolargeandcomprehensivetobecon-
sidered as a supplement to a networking text. Our goal, therefore, is to provide a gentle
ix