From the Inside Flap
PrefaceIntroductionThis book is for people who want to write programs that communicate with each otherusing an application program interface (API) known as sockets. Some readers may bevery familiar with sockets already, as that model has become synonymous with networkprogramming. Others may need an introduction to sockets from the ground up. Thegoal of this book is to offer guidance on network programming for beginners as well asprofessionals, for those developing new network-aware applications as well as thosemaintaining existing code, and for people who simply want to understand how the networkingcomponents of their system function.All the examples in this text are actual, runnable code tested on Unix systems.However, many non-Unix systems support the sockets API and the examples arelargely operating system-independent, as are the general concepts we present. Virtuallyevery operating system (OS) provides numerous network-aware applications such asWeb browsers, email clients, and file-sharing servers. We discuss the usual partitioningof these applications into client and server and write our own small examples of thesemany times throughout the text.Presenting this material in a Unix-oriented fashion has the natural side effect of providingbackground on Unix itself, and on TCP/IP as well. Where more extensive backgroundmay be interesting, we refer the reader to other texts. Four texts are so commonlymentioned in this book that we've assigned them the following abbreviations:
- APUE: Advanced Programming in the UNIX Environment Stevens 1992
- TCPv1: TCP/IP Illustrated, Volume 1 Stevens 1994
- TCPv2: TCP/IP Illustrated, Volume 2 Wright and Stevens 1995
- TCPv3: TCP/IP Illustrated, Volume 3 Stevens 1996
TCPv2 contains a high level of detail very closely related to the material in this book, asit describes and presents the actual 4.4BSD implementation of the network programmingfunctions for the sockets API (socket, bind, connect, and so on). If one understandsthe implementation of a feature, the use of that feature in an application makesmore sense.Changes from the Second EditionSockets have been around, more or less in their current form, since the 1980s, and it is atribute to their initial design that they have continued to be the network API of choice.Therefore, it may come as a surprise to learn that quite a bit has changed since the secondedition of this book was published in 1998. The changes we've made to the text aresummarized as follows:
- This new edition contains updated information on IPv6, which was only in draft form at the time of publication of the second edition and has evolved somewhat.
- The descriptions of functions and the examples have all been updated to reflect the most recent POSIX specification (POSIX 1003.1-2001), also known as the Single Unix Specification Version 3.
- The coverage of the X/Open Transport Interface (XTI) has been dropped. That API has fallen out of common use and even the most recent POSIX specification does not bother to cover it.
- The coverage of TCP for transactions (T/TCP) has been dropped.
- Three chapters have been added to describe a relatively new transport protocol, SCTP. This reliable, message-oriented protocol provides multiple streams between endpoints and transport-level support for multihoming. It was originally designed for transport of telephony signaling across the Internet, but provides some features that many applications could take advantage of.
- A chapter has been added on key management sockets, which may be used with Internet Protocol Security (IPsec) and other network security services.
- The machines used, as well as the versions of their variants of Unix, have all been updated, and the examples have been updated to reflect how these machines behave. In many cases, examples were updated because OS vendors fixed bugs or added features, but as one might expect, we've discovered the occasional new bug here and there. The machines used for testing the examples in this book were:
- Apple Power PC running MacOS/X 10.2.6
- HP PA-RISC running HP-UX 11i
- IBM Power PC running AIX 5.1
- Intel x86 running FreeBSD 4.8
- Intel x86 running Linux 2.4.7
- Sun SPARC running FreeBSD 5.1
- Sun SPARC running Solaris 9
See Figure 1.16 for details on how these machines were used.Volume 2 of this UNIX Network Programming series, subtitled Interprocess Communications,builds on the material presented here to cover message passing, synchronization,shared memory, and remote procedure calls.Using This BookThis text can be used as either a tutorial on network programming or as a reference forexperienced programmers. When used as a tutorial or for an introductory class on networkprogramming, the emphasis should be on Part 2, ''Elementary Sockets'' (Chapters3 through 11), followed by whatever additional topics are of interest. Part 2 covers thebasic socket functions for both TCP and UDP, along with SCTP, I/O multiplexing,socket options, and basic name and address conversions. Chapter 1 should be read byall readers, especially Section 1.4, which describes some wrapper functions usedthroughout the text. Chapter 2 and perhaps Appendix A should be referred to as necessary,depending on the reader 's background. Most of the chapters in Part 3, ''AdvancedSockets,'' can be read independently of the others in that part of the book.To aid in the use of this book as a reference, a thorough index is provided, alongwith summaries on the end papers of where to find detailed descriptions of all the functionsand structures. To help those reading topics in a random order, numerous referencesto related topics are provided throughout the text.The best way to learn network programming is to take these programs,modify them, and enhance them. Actually writing code of this form is the onlyway to reinforce the concepts and techniques. Numerous exercises are also provided atthe end of each chapter, and most answers are provided in Appendix E.A current errata for the book is also available from the same Web site.The authors welcome electronic mail from any readers with comments, suggestions,or bug fixes.Bill FennerWoodside, CaliforniaAndrew M. RudoffBoulder, ColoradoOctober 2003authors@unpbook.
From the Back Cover
UNIX Network Programming, Volume 1: The Sockets Networking API, Third Edition
"Everyone will want this book because it provides a great mix of practical experience, historical perspective, and a depth of understanding that only comes from being intimately involved in the field. I've already enjoyed and learned from reading this book, and surely you will too."
--Sam Leffler The classic guide to UNIX networking APIs... now completely updated!
To build today's highly distributed, networked applications and services, you need deep mastery of sockets and other key networking APIs. One book delivers comprehensive, start-to-finish guidance for building robust, high-performance networked systems in any environment: UNIX Network Programming, Volume 1, Third Edition.
Building on the legendary work of W. Richard Stevens, this edition has been fully updated by two leading network programming experts to address today's most crucial standards, implementations, and techniques. New topics include:
- POSIX Single UNIX Specification Version 3
- IPv6 APIs (including updated guidance on IPv6/IPv4 interoperability)
- The new SCTP transport protocol
- IPsec-based Key Management Sockets
- FreeBSD 4.8/5.1, Red Hat Linux 9.x, Solaris 9, AIX 5.x, HP-UX, and Mac OS X implementations
- New network program debugging techniques
- Source Specific Multicast API, the key enabler for widespread IP multicast deployment
The authors also update and extend Stevens' definitive coverage of these crucial UNIX networking standards and techniques:
- Sockets: elementary, advanced, routed, and raw
- I/O: multiplexing, advanced functions, nonblocking, and signal-driven
- Broadcasting and multicasting
- Design: TCP iterative, concurrent, preforked, and prethreaded servers
Since 1990, network programmers have turned to one source for the insights and techniques they need: W. Richard Stevens' UNIX Network Programming. Now, there's an edition specifically designed for today's challenges--and tomorrow's.