Preface

Part 1.Introduction and TCP/IP 1

Chapter 1.Introduction 3

1.1Introduction3

1.2A Simple Daytime Client6

1.3Protocol Independence9

1.4Error Handling: Wrapper Functions11

1.5A Simple Daytime Server13

1.6Road Map to Client-Server Examples in the Text16

1.7OSI Model18

1.8BSD Networking History19

1.9Test Networks and Hosts20

1.10Unix Standards24

1.1164-bit Architectures27

1.12Summary28

Chapter 2.The Transport Layer: TCP and UDP 29

2.1Introduction29

2.2The Big Picture30

2.3UDP: User Datagram Protocol32

2.4TCP: Transmission Control Protocol32

2.5TCP Connection Establishment and Termination34

2.6TIME_WAIT State40

2.7Port Numbers41

2.8TCP Port Numbers and Concurrent Servers44

2.9Buffer Sizes and Limitations46

2.10Standard Internet Services50

2.11Protocol Usage by Common Internet Applications52

2.12Summary52

Part 2.Elementary Sockets 55

Chapter 3.Sockets Introduction 57

3.1Introduction57

3.2Socket Address Structures57

3.3Value-Result Arguments63

3.4Byte Ordering Functions66

3.5Byte Manipulation Functions69

3.6inet_aton, inet_addr, and inet_ntoa Functions70

3.7inet_pton and inet_ntop Functions72

3.8sock_ntop and Related Functions75

3.9readn, writen, and readline Functions77

3.10isfdtype Function81

3.11Summary82

Chapter 4.Elementary TCP Sockets 85

4.1Introduction85

4.2socket Function85

4.3connect Function89

4.4bind Function91

4.5listen Function93

4.6accept Function99

4.7fork and exec Functions102

4.8Concurrent Servers104

4.9close Function107

4.10getsockname and getpeername Functions107

4.11Summary110

Chapter 5.TCP Client-Server Example 111

5.1Introduction111

5.2TCP Echo Server: main Function112

5.3TCP Echo Server: str_echo Function113

5.4TCP Echo Client: main Function113

5.5TCP Echo Client: str_cli Function115

5.6Normal Startup115

5.7Normal Termination117

5.8Posix Signal Handling119

5.9Handling SIGCHLD Signals122

5.10wait and waitpid Functions124

5.11Connection Abort before accept Returns129

5.12Termination of Server Process130

5.13SIGPIPE Signal132

5.14Crashing of Server Host133

5.15Crashing and Rebooting of Server Host134

5.16Shutdown of Server Host135

5.17Summary of TCP Example135

5.18Data Format137

5.19Summary140

Chapter 6.I/O Multiplexing: The select and poll Functions 143

6.1Introduction143

6.2I/O Models144

6.3select Function150

6.4str_cli Function (Revisited)155

6.5Batch Input157

6.6shutdown Function160

6.7str_cli Function (Revisited Again)161

6.8TCP Echo Server (Revisited)162

6.9pselect Function168

6.10poll Function169

6.11TCP Echo Server (Revisited Again)172

6.12Summary175

Chapter 7.Socket Options 177

7.1Introduction177

7.2getsockopt and setsockopt Functions178

7.3Checking If an Option Is Supported and Obtaining the Default178

7.4Socket States183

7.5Generic Socket Options183

7.6IPv4 Socket Options197

7.7ICMPv6 Socket Option199

7.8IPv6 Socket Options199

7.9TCP Socket Options201

7.10fcntl Function205

7.11Summary207

Chapter 8.Elementary UDP Sockets 211

8.1Introduction211

8.2recvfrom and sendto Functions212

8.3UDP Echo Server: main Function213

8.4UDP Echo Server: dg_echo Function214

8.5UDP Echo Client: main Function216

8.6UDP Echo Client: dg_cli Function217

8.7Lost Datagrams217

8.8Verifying Received Response218

8.9Server Not Running220

8.10Summary of UDP example221

8.11connect Function with UDP224

8.12dg_cli Function (Revisited)227

8.13Lack of Flow Control with UDP228

8.14Determining Outgoing Interface with UDP231

8.15TCP and UDP Echo Server Using select233

8.16Summary235

Chapter 9.Elementary Name and Address Conversions 237

9.1Introduction237

9.2Domain Name System237

9.3gethostbyname Function240

9.4RES_USE_INET6 Resolver Option245

9.5gethostbyname2 Function and IPv6 Support246

9.6gethostbyaddr Function248

9.7uname Function249

9.8gethostname Function250

9.9getservbyname and getservbyport Functions251

9.10Other Networking Information255

9.11Summary256

Part 3.Advanced Sockets 259

Chapter 10.IPv4 and IPv6 Interoperability 261

10.1Introduction261

10.2IPv4 Client, IPv6 Server262

10.3IPv6 Client, IPv4 Server265

10.4IPv6 Address Testing Macros267

10.5IPV6_ADDRFORM Socket Option268

10.6Source Code Portability270

10.7Summary271

Chapter 11.Advanced Name and Address Conversions 273

11.1Introduction273

11.2getaddrinfo Function273

11.3gai_strerror Function278

11.4freeaddrinfo Function279

11.5getaddrinfo Function: IPv6 and Unix Domain279

11.6getaddrinfo Function: Examples282

11.7host_serv Function284

11.8tcp_connect Function285

11.9tcp_listen Function288

11.10udp_client Function293

11.11udp_connect Function295

11.12udp_server Function296

11.13getnameinfo Function298

11.14Reentrant Functions300

11.15gethostbyname_r and gethostbyaddr_r Functions303

11.16Implementation of getaddrinfo and getnameinfo Functions305

11.17Summary328

Chapter 12.Daemon Processes and inetd Superserver 331

12.1Introduction331

12.2syslogd Daemon332

12.3syslog Function333

12.4daemon_init Function335

12.5inetd Daemon339

12.6daemon_inetd Function344

12.7Summary346

Chapter 13.Advanced I/O Functions 349

13.1Introduction349

13.2Socket Timeouts349

13.3recv and send Functions354

13.4readv and writev Functions357

13.5recvmsg and sendmsg Functions358

13.6Ancillary Data362

13.7How Much Data Is Queued?365

13.8Sockets and Standard I/O366

13.9T/TCP: TCP for Transactions369

13.10Summary371

Chapter 14.Unix Domain Protocols 373

14.1Introduction373

14.2Unix Domain Socket Address Structure374

14.3socketpair Function376

14.4Socket Functions377

14.5Unix Domain Stream Client-Server378

14.6Unix Domain Datagram Client-Server379

14.7Passing Descriptors381

14.8Receiving Sender Credentials390

14.9Summary394

Chapter 15.Nonblocking I/O 397

15.1Introduction397

15.2Nonblocking Reads and Writes: str_cli Function (Revisited)399

15.3Nonblocking connect409

15.4Nonblocking connect: Daytime Client410

15.5Nonblocking connect: Web Client413

15.6Nonblocking accept422

15.7Summary424

Chapter 16.ioctl Operations 425

16.1Introduction425

16.2ioctl Function426

16.3Socket Operations426

16.4File Operations427

16.5Interface Configuration428

16.6get_ifi_info Function429

16.7Interface Operations439

16.8ARP Cache Operations440

16.9Routing Table Operations442

16.10Summary443

Chapter 17.Routing Sockets 445

17.1Introduction445

17.2Datalink Socket Address Structure446

17.3Reading and Writing447

17.4sysctl Operations454

17.5get_ifi_info Function459

17.6Interface Name and Index Functions463

17.7Summary467

Chapter 18.Broadcasting 469

18.1Introduction469

18.2Broadcast Addresses470

18.3Unicast versus Broadcast472

18.4dg_cli Function Using Broadcasting475

18.5Race Conditions478

18.6Summary486

Chapter 19.Multicasting 487

19.1Introduction487

19.2Multicast Addresses487

19.3Multicasting versus Broadcasting on A LAN490

19.4Multicasting on a WAN493

19.5Multicast Socket Options495

19.6mcast_join and Related Functions499

19.7dg_cli Function Using Multicasting502

19.8Receiving MBone Session Announcements504

19.9Sending and Receiving507

19.10SNTP: Simple Network Time Protocol510

19.11SNTP (Continued)515

19.12Summary528

Chapter 20.Advanced UDP Sockets 531

20.1Introduction531

20.2Receiving Flags, Destination IP Address, and Interface Index532

20.3Datagram Truncation539

20.4When to Use UDP Instead Of TCP539

20.5Adding Reliability to a UDP Application542

20.6Binding Interface Addresses553

20.7Concurrent UDP Servers557

20.8IPv6 Packet Information560

20.9Summary562

Chapter 21.Out-of-Band Data 565

21.1Introduction565

21.2TCP Out-of-Band Data565

21.3sockatmark Function572

21.4TCP Out-of-Band Data Summary580

21.5Client-Server Heartbeat Functions581

21.6Summary586

Chapter 22.Signal-Driven I/O 589

22.1Introduction589

22.2Signal-Driven I/O for Sockets590

22.3UDP Echo Server Using SIGIO592

22.4Summary598

Chapter 23.Threads 601

23.1Introduction601

23.2Basic Thread Functions: Creation and Termination602

23.3str_cli Function Using Threads605

23.4TCP Echo Server Using Threads607

23.5Thread-Specific Data611

23.6Web Client and Simultaneous Connections (Continued)620

23.7Mutexes: Mutual Exclusion622

23.8Condition Variables627

23.9Web Client and Simultaneous Connections (Continued)631

23.10Summary633

Chapter 24.IP Options 635

24.1Introduction635

24.2IPv4 Options635

24.3IPv4 Source Route Options637

24.4IPv6 Extension Headers645

24.5IPv6 Hop-by-Hop Options and Destination Options645

24.6IPv6 Routing Header649

24.7IPv6 Sticky Options653

24.8Summary654

Chapter 25.Raw Sockets 655

25.1Introduction655

25.2Raw Socket Creation656

25.3Raw Socket Output657

25.4Raw Socket Input659

25.5Ping Program661

25.6Traceroute Program672

25.7An ICMP Message Daemon685

25.8Summary702

Chapter 26.Datalink Access 703

26.1Introduction703

26.2BPF: BSD Packet Filter704

26.3DLPI: Data Link Provider Interface706

26.4Linux: SOCK_PACKET707

26.5libpcap: Packet Capture Library707

26.6Examining the UDP Checksum Field708

26.7Summary725

Chapter 27.Client-Server Design Alternatives 727

27.1Introduction727

27.2TCP Client Alternatives730

27.3TCP Test Client730

27.4TCP Iterative Server732

27.5TCP Concurrent Server, One Child per Client732

27.6TCP Preforked Server, No Locking around accept736

27.7TCP Preforked Server, File Locking around accept742

27.8TCP Preforked Server, Thread Locking around accept745

27.9TCP Preforked Server, Descriptor Passing746

27.10TCP Concurrent Server, One Thread per Client752

27.11TCP Prethreaded Server, per-Thread accept754

27.12TCP Prethreaded Server, Main Thread accept756

27.13Summary759

Part 4.XTI: X/Open Transport Interface 761

Chapter 28.XTI: TCP Clients 763

28.1Introduction763

28.2t_open Function764

28.3t_error and t_strerror Functions767

28.4netbuf Structures and XTI Structures769

28.5t_bind Function770

28.6t_connect Function772

28.7t_rcv and t_snd Functions773

28.8t_look Function774

28.9t_sndrel and t_rcvrel Functions775

28.10t_snddis and t_rcvdis Functions777

28.11XTI TCP Daytime Client778

28.12xti_rdwr Function781

28.13Summary782

Chapter 29.XTI: Name and Address Functions 783

29.1Introduction783

29.2/etc/netconfig File and netconfig Functions784

29.3NETPATH Variable and netpath Functions785

29.4netdir Functions786

29.5t_alloc and t_free Functions788

29.6t_getprotaddr Functions790

29.7xti_ntop Function791

29.8tcp_connect Function792

29.9Summary796

Chapter 30.XTI: TCP Servers 797

30.1Introduction797

30.2t_listen Function799

30.3tcp_listen Function800

30.4t_accept Function802

30.5xti_accept Function803

30.6Simple Daytime Server804

30.7Multiple Pending Connections806

30.8xti_accept Function (Revisited)808

30.9Summary816

Chapter 31.XTI: UDP Clients and Servers 819

31.1Introduction819

31.2t_rcvudata and t_sndudata Functions819

31.3udp_client Function820

31.4t_rcvuderr Function: Asynchronous Errors824

31.5udp_server Function826

31.6Reading a Datagram in Pieces829

31.7Summary831

Chapter 32.XTI Options 833

32.1Introduction833

32.2t_opthdr Structure835

32.3XTI Options837

32.4t_optmgmt Function840

32.5Checking If an Option Is Supported and Obtaining the Default841

32.6Getting and Setting XTI Options844

32.7Summary848

Chapter 33.Streams 849

33.1Introduction849

33.2Overview850

33.3getmsg and putmsg Functions854

33.4getpmsg and putpmsg Functions855

33.5ioctl Function855

33.6TPI: Transport Provider Interface856

33.7Summary866

Chapter 34.XTI: Additional Functions 867

34.1Introduction867

34.2Nonblocking I/O867

34.3t_rcvconnect Function868

34.4t_getinfo Function869

34.5t_getstate Function869

34.6t_sync Function870

34.7t_unbind Function872

34.8t_rcvv and t_rcvvudata Functions872

34.9t_sndv and t_sndvudata Functions873

34.10t_rcvreldata and t_sndreldata Functions874

34.11Signal-Driven I/O874

34.12Out-of-Band Data875

34.13Loopback Transport Providers880

34.14Summary881

Appendix A.IPv4, IPv6, ICMPv4, and ICMPv6 883

A.1Introduction883

A.2IPv4 Header883

A.3IPv6 Header885

A.4IPv4 Addresses887

A.5IPv6 Addresses892

A.6ICMPv4 and ICMPv6: Internet Control Message Protocol896

Appendix B.Virtual Networks 899

B.1Introduction899

B.2The MBone899

B.3The 6bone901

Appendix C.Debugging Techniques 903

C.1System Call Tracing903

C.2Standard Internet Services908

C.3sock Program908

C.4Small Test Programs911

C.5tcpdump Program913

C.6netstat Program914

C.7lsof Program914

Appendix D.Miscellaneous Source Code 915

D.1unp.h Header915

D.2config.h Header919

D.3unpxti.h Header920

D.4Standard Error Functions922

Appendix E.Solutions to Selected Exercises 925

Bibliography 963

Index 971