UNIX Network Programming

Transcription

1 UNIX Network Programming The Sockets Networking API Volume 1 Third Edition W. Richard Stevens Bill Fenner Andrew M. Rudoff AAddison-Wesley Boston San Francisco New York Toronto Montreal London Munich Paris Madrid Capetown Sydney Tokyo Singapore Mexico City

2 Contents Foreword Preface XVII xix Part 1. Introduction and TCP/IP Chapter 1. Introduction 1.1 Introduction A Simple Daytime Client Protocol Independence Error Handling: Wrapper Functions A Simple Daytime Server Roadmap to Client/Server Examples in the Text 1.7 OSI Model BSD Networking History Test Networks and Hosts Unix Standards Bit Architectures Summary Chapter 2. The Transport Layer: TCP, UDP, and SCTP 2.1 Introduction The Big Picture User Datagram Protocol (UDP) 34 31

3 viii UNIX Network Programming Contents 2.4 Transmission Control Protocol (TCP) Stream Control Transmission Protocol (SCTP) TCP Connection Establishment and Termination TIMEJA/AIT State SCTP Association Establishment and Termination Port Numbers TCP Port Numbers and Concurrent Servers Buffer Sizes and Limitations Standard Internet Services Protocol Usage by Common Internet Applications Summary 63 Part 2. Elementary Sockets 65 Chapter 3. Sockets Introduction Introduction Socket Address Structures Value-Result Arguments Byte Ordering Functions Byte Manipulation Functions inet_aton, inet_addr, and inet_ntoa Functions inet_pton and inet_ntop Functions sock_ntop and Related Functions readn, writen, and readline Functions Summary 92 Chapter 4. Elementary TCP Sockets Introduction socket Function connect Function bind Function listen Function accept Function fork and exec Functions Concurrent Servers close Function getsockname and getpeername Functions Summary 120 Chapter 5. TCP Client/Server Example Introduction TCP Echo Server: main Function TCP Echo Server: str_echo Function TCP Echo Client: main Function TCP Echo Client: str_cli Function Normal Startup Normal Termination 128

4 UNIX Network Programming Contents ix 5.8 POSIX Signal Handling Handling SIGCHLD Signals wait and waitpid Functions Connection Abort betöre accept Returns Termination of Server Process SIGPIPE Signal Crashing of Server Host Crashing and Rebooting of Server Host Shutdown of Server Host Summary of TCP Example Data Format Summary 151 Chapter 6. I/O Multiplexing: The select and poll Functions Introduction I/O Models select Function str_cli Function (Revisited) Batch Input and Buffering shutdown Function str_cli Function (Revisited Again) TCP Echo Server (Revisited) pselect Function poll Function TCP Echo Server (Revisited Again) Summary 188 Chapter 7. Socket Options Introduction getsockopt and setsockopt Functions Checking if an Option Is Supported and Obtaining the Default Socket States Generic Socket Options IPv4 Socket Options ICMPv6 Socket Option IPv6 Socket Options TCP Socket Options SCTP Socket Options fcntl Function Summary 236 Chapter 8. Elementary UDP Sockets Introduction recvfrom and sendto Functions UDP Echo Server: main Function UDP Echo Server: dg_echo Function UDP Echo Client: main Function UDP Echo Client: dgcli Function 245

5 x UNIX Network Programming Contents 8.7 Lost Datagrams Verifying Received Response Server Not Running Summary of UDP Example connect Function with UDP dg_cli Function (Revisited) Lack of Flow Control with UDP Determining Outgoing Interface with UDP TCP and UDP Echo Server Using select Summary 264 Chapter 9. Elementary SCTP Sockets Introduction Interface Models sctpbindx Function sctp_connectx Function sctp_getpaddrs Function sctp_freepaddrs Function sctp_getladdrs Function sctp_freeladdrs Function sctp_sendmsg Function sctp_recvmsg Function sctp_opt_info Function sctp_peeloff Function shutdown Function Notifications Summary 286 Chapter 10. SCTP Client/Server Example Introduction SCTP One-to-Many-Style Streaming Echo Server: main Function SCTP One-to-Many-Style Streaming Echo Client: main Function SCTP Streaming Echo Client: strcli Function Exploring Head-of-Line Blocking Controlling the Number of Streams Controlling Termination Summary 301 Chapter 11. Name and Address Conversions Introduction Domain Name System (DNS) gethostbyname Function gethostbyaddr Function getservbyname and getservbyport Functions getaddrinfo Function gai_strerror Function freeaddrinfo Function getaddrinfo Function: IPv6 322

6 UNIX Network Programming Contents xi getaddrinfo Function: Examples host_serv Function tcp_connect Function tcp listen Function udp_client Function udp_connect Function udpserver Function getnameinfo Function Re-entrant Functions gethostbyname_r and gethostbyaddr_r Obsolete IPv6 Address Lookup Functions Other Networking Information Summary 349 Functions Part 3. Advanced Sockets 351 Chapter Chapter Chapter IPv4 and IPv6 Interoperability Introduction 353 IPv4 Client, IPv6 Server 354 IPv6 Client, IPv4 Server 357 IPv6 Address-Testing Macros 360 Source Code Portability 361 Summary 362 Daemon Processes and the inetd Superserver Introduction 363 syslogd Daemon 364 syslog Function 365 daemon_init Function 367 inetd Daemon 371 daemon_inetd Function 377 Summary 379 Advanced I/O Functions Introduction 381 Socket Timeouts 381 recv and send Functions 387 readv and writev Functions 389 recvmsg and sendmsg Functions 390 Ancillary Data 395 How Much Data Is Queued? 398 Sockets and Standard I/O 399 Advanced Polling 402 Summary

7 xii UNIX Network Programming Contents Chapter Chapter Unix Domain Protocols 411 Introduction 411 Unix Domain Socket Address Structure 412 socketpair Function 414 Socket Functions 415 Unix Domain Stream Client/Server 416 Unix Domain Datagram Client/Server 418 Passing Descriptors 420 Receiving Sender Credentials 429 Summary 432 Nonblocking I/O 435 Introduction 435 Nonblocking Reads and Writes: strcli Function (Revisited) 437 Nonblocking connect 448 Nonblocking connect: Daytime Client 449 Nonblocking connect: Web Client 452 Nonblocking accept 461 Summary 463 Chapter Chapter ioctl Operations Introduction 465 ioctl Function 466 Socket Operations 466 File Operations 468 Interface Configuration 468 get_ifi_info Function 469 Interface Operations 480 ARP Cache Operations 481 Routing Table Operations 483 Summary 484 Routing Sockets Introduction 485 Datalink Socket Address Structure Reading and Writing 487 sysctl Operations 495 get_ifi_info Function (Revisited) Interface Name and Index Functions Summary Chapter Key Management Sockets Introduction 511 Reading and Writing 512 Dumping the Security Association Database (SADB) Creating a Static Security Association (SA) 517 Dynamically Maintaining SAs 524 Summary

8 UNIX Network Programming Contents xiii Chapter 20. Broadcasting 20.1 Introduction Broadcast Addresses Unicast versus Broadcast dgcli Function Using Broadcasting 20.5 Race Conditions Summary Chapter 21. Multicasting 21.1 Introduction Multicast Addresses Multicasting versus Broadcasting on a LAN Multicasting on a WAN Source-Specific Multicast Multicast Socket Options mcast_join and Related Functions 21.8 dgcli Function Using Multicasting Receiving IP Multicast Infrastructure Session Announcements Sending and Receiving Simple Network Time Protocol (SNTP) Summary Chapter 22. Advanced UDP Sockets 22.1 Introduction Receiving Flags, Destination IP Address, and Interface Index 22.3 Datagram Truncation When to Use UDP Instead of TCP Adding Reliability to a UDP Application Binding Interface Addresses Concurrent UDP Servers IPv6 Packet Information IPv6 Path MTU Control Summary Chapter 23. Advanced SCTP Sockets 23.1 Introduction An Autoclosing One-to-Many-Style Server Partial Delivery Notifications Unordered Data Binding a Subset of Addresses Determining Peer and Local Address Information 23.8 Finding an Association ID Given an IP Address 23.9 Heartbeating and Address Failure Peeling Off an Association Controlling Timing When to Use SCTP Instead of TCP Summary

9 xiv UNIX Network Programming Contents Chapter 24. Out-of-Band Data 24.1 Introduction TCP Out-of-Band Data sockatmark Function TCP Out-of-Band Data Recap 24.5 Summary Chapter Signal-Driven I/O Introduction 663 Signal-Driven I/O for Sockets UDP Echo Server Using SIGIO Summary Chapter 26. Threads 26.1 Introduction Basic Thread Functions: Creation and Termination strcli Function Using Threads TCP Echo Server Using Threads Thread-Specific Data Web Client and Simultaneous Connections (Continued) Mutexes: Mutual Exclusion Condition Variables Web Client and Simultaneous Connections (Continued) Summary Chapter 27. IP Options 27.1 Introduction IPv4 Options IPv4 Source Route Options IPv6 Extension Headers IPv6 Hop-by-Hop Options and Destination Options 27.6 IPv6 Routing Header IPv6 Sticky Options Historical IPv6 Advanced API Summary Chapter 28. Raw Sockets 28.1 Introduction Raw Socket Creation Raw Socket Output Raw Socket Input ping Program traceroute Program An ICMP Message Daemon Summary

10 UNIX Network Programming Contents xv Chapter 29. Datalink Access 29.1 Introduction BSD Packet Filter (BPF) Datalink Provider Interface (DLPI) Linux: SOCK_PACKET and PF_PACKET libpcap: Packet Capture Library libnet: Packet Creation and Injection Library 29.7 Examining the UDP Checksum Field Summary Chapter Client/Server Design Alternatives Introduction 817 TCP Client Alternatives 819 TCP Test Client 820 TCP Iterative Server 821 TCP Concurrent Server, One Child per Client 822 TCP Preforked Server, No Locking Around accept 826 TCP Preforked Server, File Locking Around accept 832 TCP Preforked Server, Thread Locking Around accept 835 TCP Preforked Server, Descriptor Passing 836 TCP Concurrent Server, One Thread per Client 842 TCP Prethreaded Server, per-thread accept 844 TCP Prethreaded Server, Main Thread accept 846 Summary Chapter 31. STREAMS 31.1 Introduction Overview getmsg and putmsg Functions 31.4 getpmsg and putpmsg Functions 31.5 ioctl Function Transport Provider Interface (TPI) 31.7 Summary Appendix A. IPv4, IPv6, ICMPv4, and ICMPv6 A.1 Introduction 869 A.2 IPv4 Header 869 A.3 IPv6 Header 871 A.4 IPv4 Addresses 874 A.5 IPv6 Addresses 877 A.6 Internet Control Message Protocols (ICMPv4 and ICMPv6) Appendix B. Virtual Networks B.1 Introduction 885 B.2 The MBone 885 B.3 The 6bone 887 B.4 IPv6 Transition: 6to

11 xvi UNIX Network Programming Contents Appendix C. C.1 C.2 C.3 C.4 C.5 C.6 C.7 Appendix D, D.1 D.2 D.3 Debugging Techniques System Call Tracing 891 Standard Internet Services 893 sock Program 893 Small Test Programs 896 tcpdump Program 896 netstat Program 896 lsof Program 897 Miscellaneous Source Code unp.h Header 899 config.h Header 904 Standard Error Functions Appendix E. Solutions to Selected Exercises 913 Bibliography Index