TCP IP Sockets in C#: Practical Guide for Programmers (The Practical Guides)

188 Pages·2004·1.67 MB·English

by  Michael J. Donahoo, Kenneth L. Calvert, 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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For further information on these books and for a list of forthcoming titles,
please visit our website at http://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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For Margie and Jacob, for their love and inspiration
–David
For my three girls: Lisa, Michaela, and Mackenzie
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For my parents, Paul and Eleanor Calvert
–Ken
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Contents
Preface ix
1 Introduction 1
1.1 Networks, Packets, and Protocols 1
1.2 About Addresses 4
1.3 About Names 5
1.4 Clients and Servers 5
1.5 What Is a Socket? 6
1.6 Exercises 7
2 Basic Sockets 9
2.1 Socket Addresses 9
2.2 Socket Implementation in .NET 15
2.3 TCP Sockets 16
2.4 UDP Sockets 29
2.5 The .NET Socket Class 37
2.6 Exercises 57
3 Sending and Receiving Messages 59
3.1 Encoding Information 61
3.2 Composing I/O Streams 65
3.3 Framing and Parsing 66
3.4 Implementing Wire Formats in C# 70
3.5 Wrapping Up 83
3.6 Exercises 84
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viii Contents ■
4 Beyond the Basics 85
4.1 Nonblocking I/O 85
4.2 Multiplexing 95
4.3 Threads 99
4.4 Asynchronous I/O 117
4.5 Multiple Recipients 131
4.6 Closing Connections 138
4.7 Wrapping Up 145
4.8 Exercises 146
5 Under the Hood 147
5.1 Buffering and TCP 149
5.2 Buffer Deadlock 152
5.3 Performance Implications 154
5.4 TCP Socket Life Cycle 155
5.5 Demultiplexing Demystified 165
5.6 Exercises 167
Appendix: Handling Socket Errors 169
Bibliography 171
Index 173
Preface
For years, college courses in computer networking were taught with little or no “hands on”
experience. For various reasons, including some good ones, instructors approached the
principles of computer networking primarily through equations, analyses, and abstract
descriptions of protocol stacks. Textbooks might include code, but it was unconnected to
anything students could get their hands on. Perhaps in an ideal world this would suffice,
but we believe that students learn better when they can see (and then build) concrete
examples of the principles at work. Fortunately, such examples abound today. The Internet
has become a part of everyday life, and access to its services is readily available to most
students (and their programs).
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
“Internet time”—but it is likely to remain important for the foreseeable future.
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-
work programming, we know of none that cover TCP/IP sockets. Excellent reference books
on TCP/IP socket programming exist, but they are too large and comprehensive to be con-
sidered as a supplement to a networking text. Our goal, therefore, is to provide a gentle
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