TCP/IP Illustrated, Volume 2 The Implementation

Transcription

1 TCP/IP Illustrated, Volume 2 The Implementation W. Richard Stevens Gary R. Wright ADDISON-WESLEY PUBLISHING COMPANY Reading, Massachusetts Menlo Park, California New York Don Mills, Ontario Wokingham, England Amsterdam Bonn Sydney Singapore Tokyo Madrid San Juan Paris Seoul Milan Mexico City Taipei

2 Contents Preface xix Chapter Introduction Introduction 1 Source Code Presentation 1 History 3 Application Programming Interfaces 5 Example Program 5 System Calls and Library Functions 7 Network Implementation Overview 9 Descriptors 10 Mbufs (Memory Buffers) and Output Processing Input Processing 19 Network Implementation Overview Revisited 22 Interrupt Levels and Concurrency 23 Source Code Organization 26 Test Network 28 Summary Chapter Mbufs: Memory Buffers Introduction 31 Code Introduction 36 Mbuf Definitions 37 mbuf Structure 38 Simple Mbuf Macros and Functions 40 m_devget and m_pullup Functions 44 31

3 TCP/IP Illustrated Contents 2.7 Summary of Mbuf Macros and Functions Summary of Net/3 Networking Data Structures m_copy and Cluster Reference Counts Alternatives Summary 60 Chapter 3. Interface Layer Introduction Code Introduction if net Structure ifaddr Structure sockaddr Structure if net and ifaddr Specialization Network Initialization Overview Ethernet Initialization SLIP Initialization Loopback Initialization if_attach Function ifinit Function Summary 94 Chapter 4. Interfaces: Ethernet Introduction Code Introduction Ethernet Interface 98» 4.4 ioctl System Call Summary 125 Chapter 5. Interfaces: SLIP and Loopback Introduction Code Introduction SLIP Interface Loopback Interface Summary 153 Chapter 6. IP Addressing Introduction Code Introduction Interface and Address Summary sockaddr_in Structure in_ifaddr Structure Address Assignment Interface ioctl Processing Internet Utility Functions if net Utility Functions Summary 183

4 TCP/IP Illustrated Contents xi Chapter 7. Domains and Protocols 7.1 Introduction Code Introduction domain Structure protosw Structure IP domain and protosw Structures pffindproto and pffindtype Functions 7.7 pfctlinput Function IP Initialization sysctl System Call Summary Chapter 8. Chapter 9. 4 IP: Internet Protocol 8.1 Introduction Code Introduction IP Packets Input Processing: ipintr Function Forwarding: ip_forward Function Output Processing: ip_output Function Internet Checksum: in_cksum Function setsockopt and getsockopt System Calls ip_sysctl Function Summary 245 IP Option Processing 9.1 Introduction Code Introduction Option Format ip_dooptions Function Record Route Option Source and Record Route Options Timestamp Option ip_insertoptions Function ip_pcbopts Function Limitations Summary 272 Chapter 10. IP Fragmentation and Reassembly 10.1 Introduction Code Introduction Fragmentation ip_optcopy Function Reassembly ip_reass Function ip_slowtimo Function Summary

5 xii TCP/IP Illustrated Contents Chapter 11. Chapter 12. ICMP: Internet Control Message Protocol 11.1 Introduction Code Introduction icmp Structure ICMP protosw Structure Input Processing: icmp_input Function 11.6 Error Processing Request Processing Redirect Processing Reply Processing Output Processing icmp_error Function icmp_reflect Function icmp_send Function icmp_sysctl Function Summary 335 IP Multicasting 12.1 Introduction Code Introduction Ethernet Multicast Addresses 341 " 12.4 ether_multi Structure Ethernet Multicast Reception in_multi Structure ip_moptions Structure 347 i 12.8 Multicast Socket Options Multicast TTL Values ip_setmoptions Function Joining an IP Multicast Group Leaving an IP Multicast Group ip_getmoptions Function Multicast Input Processing: ipintr Function Multicast Output Processing: ip_output Function Performance Considerations Summary 379 Chapter IGMP: Internet Group Management Protocol 13.1 Introduction Code Introduction igmp Structure IGMP protosw Structure Joining a Group: igmp_joingroup Function igmp_fasttimo Function Input Processing: igmp_input Function Leaving a Group: igmp_leavegroup Function Summary

6 TCP/IP Illustrated Contents xiii Chapter 14. IP Multicast Routing 14.1 Introduction Code Introduction Multicast Output Processing Revisited mrouted Daemon Virtual Interfaces IGMP Revisited Multicast Routing Multicast Forwarding: ip_mforward Function 14.9 Cleanup: ip_mrouter_done Function Summary Chapter Socket Layer 15.1 Introduction Code Introduction socket Structure System Calls Processes, Descriptors, and Sockets socket System Call get sock and sockargs Functions bind System Call listen System Call tsleep and wakeup Functions accept System Call sonewconn and soisconnected Functions connect System call shutdown System Call close System Call Summary Chapter 16. Socket I/O 16.1 Introduction Code Introduction Socket Buffers write, writev, sendto, and sendmsg System Calls 16.5 sendmsg System Call sendit Function sosend Function read, readv, recvfrom, 16.9 recvmsg System Call recvit Function soreceive Function soreceive Code select System Call Summary 534 and recvmsg System Calls

7 xiv TCP/IP Illustrated Contents Chapter 17. Chapter 18. Chapter Chapter 20. Socket Options 17.1 Introduction Code Introduction setsockopt System Call getsockopt System Call fcntl and ioctl System Calls getsockname System Call getpeername System Call Summary 557 Radix Tree Routing Tables 18.1 Introduction Routing Table Structure Routing Sockets Code Introduction Radix Node Data Structures Routing Structures Initialization: route_init and rtable_init Functions Initialization: rn_init and rn_inithead Functions Duplicate Keys and Mask Lists rn_match Function rn_search Function Summary 599 Routing Requests and Routing Messages 19.1 Introduction rtalloc and rtallocl Functions RTFREE Macro and rtfree Function rtrequest Function rt_setgate Function rtinit Function rtredirect Function Routing Message Structures rt_missmsg Function rt_ifmsg Function rt_newaddrmsg Function rt_msgl Function rt_msg2 Function sysctl_rtable Function sysctl_dumpentry Function sysctl_iflist Function Summary 644 Routing Sockets 20.1 Introduction routedomain and protosw Structures Routing Control Blocks

8 TCP/IP Illustrated Contents xv 20.4 raw_init Function route_output Function rt_xaddrs Function rt_setmetrics Function raw_input Function route_usrreq Function raw_usrreq Function raw_attach, raw_detach, and raw_disconnect Functions Summary Chapter 21. ARP: Address Resolution Protocol 21.1 Introduction ARP and the Routing Table Code Introduction ARP Structures arpwhohas Function arprequest Function arpintr Function in_arpinput Function ARP Timer Functions arpresolve Function arplookup Function Proxy ARP arpmrtrequest Function ARP and Multicasting Summary Chapter 22. Protocol Control Blocks Introduction 713 Code Introduction 715 inpcb Structure 716 in_pcballoc and in_pcbdetach Functions 717 Binding, Connecting, and Demultiplexing 719 in_pcblookup Function 724 in_pcbbind Function 728 in_pcbconnect Function 735 in_pcbdisconnect Function 741 in_setsockaddr and in_setpeeraddr Functions 741 inj>cbnotify, in_rtchange, and in_losing Functions Implementation Refinements 750 Summary Chapter 23. UDP: User Datagram Protocol 23.1 Introduction Code Introduction UDP protosw Structure

9 xvi TCP/IP Illustrated Contents UDP Header 759 udp_init Function 760 udp_output Function 760 udp_input Function 769 udp_saveopt Function 781 udp_ctlinput Function 782 udp_usrreq Function 784 udp_sysctl Function 790 Implementation Refinements 791 Summary 793 Chapter 24. TCP: Transmission Control Protocol Introduction 795 Code Introduction 795 TCP protosw Structure 801 TCP Header 801 TCP Control Block 803 TCP State Transition Diagram 805 TCP Sequence Numbers 807 tcp_init Function 812 Summary 815 Chapter 25. TCP Timers 25.1 Introduction Code Introduction 819 (, 25.3 tcp_canceltimers Function tcp_fasttimo Function tcp_slowtimo Function tcp_timers Function Retransmission Timer Calculations tcp_newtcpcb Function tcp_setpersist Function tcp_xmit_timer Function Retransmission Timeout: tcp_timers Function An RTT Example Summary Chapter 26. TCP Output 26.1 Introduction tcp_output Overview Determine if a Segment Should be Sent 26.4 TCP Options Window Scale Option Timestamp Option Send a Segment tcp_template Function tcp_respond Function Summary

10 TCP/IP Illustrated Contents xvii Chapter 27. TCP Functions Introduction 891 tcp_drain Function tcp_drop Function tcp_close Function tcp_mss Function tcp_ctlinput Function 904 tcp_notify Function 904 tcp_quench Function 906 TCP_REASS Macro and tcp_reass Function 906 tcp_trace Function 916 Summary 920 Chapter 28. TCP Input i, Introduction 923 Preliminary Processing 925 tcp_dooptions Function 933 Header Prediction 934 TCP Input: Slow Path Processing 941 Completion of / Passive Open or Active Open 942 PAWS: Protection Against Wrapped Sequence Numbers Trim Segment so Data is Within Window 954 Self-Connects and Simultaneous Opens 960 Record Timestamp 963 RST Processing 963 Summary Chapter TCP Input (Continued) Introduction 967 ACK Processing Overview 967 Completion of Passive Opens and Simultaneous Opens Fast Retransmit and Fast Recovery Algorithms 970 ACK Processing 974 Update Window Information 981 Urgent Mode Processing 983 tcp_pulloutofband Function 986 Processing of Received Data 988 FIN Processing 990 Final Processing 992 Implementation Refinements 994 Header Compression 995 Summary Chapter 30. TCP User Requests Introduction 1007 tcp_usrreq Function 1007 tcp_attach Function 1018 tcp_disconnect Function 1019

11 xviii TCP/IP Illustrated Contents tcp_usrclosed Function 30.6 tcp_ctloutput Function 30.7 Summary Chapter 31. BPF: BSD Packet Filter 31.1 Introduction Code Introduction bpf_if Structure bpf_d Structure BPF Input BPF Output Summary Chapter 32. Epilogue Appendix A. Raw IP Introduction 1049 Code Introduction 1050 Raw IP protosw Structure 1051 rip_init Function 1053 rip_input Function 1053 rip_output Function 1056 rip_usrreq Functidn_ 1058 rip_ctloutput Function 1063 Summary 1065 Solutions to Selected Exercises Appendix B. Source Code Availability 1093 Appendix C. C.1 C.2 C.3 C.4 C.5 C.6 C.7 C.8 C.9 C.10 C.11 Bibliography Index RFC 1122 Compliance Link-Layer Requirements 1097 IP Requirements 1098 IP Options Requirements 1102 IP Fragmentation and Reassembly Requirements 1104 ICMP Requirements 1105 Multicasting Requirements 1110 IGMP Requirements 1111 Routing Requirements 1111 ARP Requirements 1113 UDP Requirements 1113 TCP Requirements