understanding linux network internals

深入理解Linux网络内幕（英文） If you've ever wondered how Linux carries out the complicated tasks assigned to it by the IP protocols -- or if you just want to learn about modern networking through real-life examples -- "Understanding Linux Network Internals" is for you. Like the popular O'Reilly book, "Understanding the Linux Kernel," this book clearly explains the underlying concepts and teaches you how to follow the actual C code that implements it. Although some background in the TCP/IP protocols is helpful, you can learn a great deal from this text about the protocols themselves and their uses. And if you already have a base knowledge of C, you can use the book's code walkthroughs to figure out exactly what this sophisticated part of the Linux kernel is doing. Part of the difficulty in understanding networks -- and implementing them -- is that the tasks are broken up and performed at many different times by different pieces of code. One of the strengths of this book is to integrate the pieces and reveal the relationships between far-flung functions and data structures. "Understanding Linux Network Internals" is both a big-picture discussion and a no-nonsense guide to the details of Linux networking. Topics include: Key problems with networking Network interface card (NIe device drivers System initialization Layer 2 (link-layer) tasks and implementation Layer 3 (IPv4) tasks and implementation Neighbor infrastructure and protocols (ARP) Bridging Routing ICMP Author Christian Benvenuti, an operating system designer specializing in networking, explains much more than how Linux code works. He shows the purposes of major networking features and the trade-offs involved inchoosing one solution over another. A large number of flowcharts and other diagrams enhance the book's understandability. Part I: General Background 背景知识 Chapter 1. Introduction 简介 Section 1.1. Basic Terminology 基础技术 Section 1.2. Common Coding Patterns 通用程序模式 Section 1.3. User-Space Tools 用户空间的工具 Section 1.4. Browsing the Source Code 浏览代码 Section 1.5. When a Feature Is Offered as a Patch 一些特性什么时候以补丁的形式提供 Chapter 2. Critical Data Structures 重要数据结构 Section 2.1. The Socket Buffer: sk_buff Structure 套接字缓存:sk_buff结构 Section 2.2. net_device Structure net_device结构 Section 2.3. Files Mentioned in This Chapter 本章所涉及的到的(代码)文件 Chapter 3. User-Space-to-Kernel Interface 从用户空间到内核态的接口 Section 3.1. Overview 简介 Section 3.2. procfs Versus sysctl Section 3.3. ioctl Section 3.4. Netlink 网络链接 Section 3.5. Serializing Configuration Changes 不断的配置变化 Part II: System Initialization 系统初始化 Chapter 4. Notification Chains (消息)通知链 Section 4.1. Reasons for Notification Chains 通知链的原因 Section 4.2. Overview 简介 Section 4.3. Defining a Chain 定义一个链 Section 4.4. Registering with a Chain 注册链 Section 4.5. Notifying Events on a Chain 在链上标记事件 Section 4.6. Notification Chains for the Networking Subsystems 网络子层的标记链 Section 4.7. Tuning via /proc Filesystem Section 4.8. Functions and Variables Featured in This Chapter 本章所涉及的到的函数与变量 Section 4.9. Files and Directories Featured in This Chapter 本章所涉及的到的(代码)文件 Chapter 5. Network Device Initialization 网络设备的组织 Section 5.1. System Initialization Overview 简介 Section 5.2. Device Registration and Initialization 设备注册与初始化 Section 5.3. Basic Goals of NIC Initialization NIC初始化的基本目标 Section 5.4. Interaction Between Devices and Kernel 设备与内核的交互 Section 5.5. Initialization Options 初始化选项 Section 5.6. Module Options 模块选项 Section 5.7. Initializing the Device Handling Layer: net_dev_init 设备处理层的初始化 Section 5.8. User-Space Helpers 用户空间的帮助 Section 5.9. Virtual Devices 虚拟设备 Section 5.10. Tuning via /proc Filesystem Section 5.11. Functions and Variables Featured in This Chapter Section 5.12. Files and Directories Featured in This Chapter Chapter 6. The PCI Layer and Network Interface Cards PCI层的网卡 Section 6.1. Data Structures Featured in This Chapter 本章的数据结构 Section 6.2. Registering a PCI NIC Device Driver PIC NIC设备驱动的注册 Section 6.3. Power Management and Wake-on-LAN 电源管理以及LAN唤醒 Section 6.4. Example of PCI NIC Driver Registration 示例 Section 6.5. The Big Picture 框架图 Section 6.6. Tuning via /proc Filesystem Section 6.7. Functions and Variables Featured in This Chapter Section 6.8. Files and Directories Featured in This Chapter Chapter 7. Kernel Infrastructure for Component Initialization 组件初始化的底层内核(实现) Section 7.1. Boot-Time Kernel Options 内核启动选项 Section 7.2. Module Initialization Code 模块初始化 Section 7.3. Optimized Macro-Based Tagging 基于标记的模块优化 Section 7.4. Boot-Time Initialization Routines 启动时的初始化例程 Section 7.5. Memory Optimizations 内存优化 Section 7.6. Tuning via /proc Filesystem Section 7.7. Functions and Variables Featured in This Chapter Section 7.8. Files and Directories Featured in This Chapter Chapter 8. Device Registration and Initialization 设备的注册与初始化 Section 8.1. When a Device Is Registered 什么时候注册一个设备 Section 8.2. When a Device Is Unregistered Section 8.3. Allocating net_device Structures 给XX结构分配内存 Section 8.4. Skeleton of NIC Registration and Unregistration NIC注册与反注册的框架 Section 8.5. Device Initialization 设备初始化 Section 8.6. Organization of net_device Structures XX结构的组织 Section 8.7. Device State 设备状态 Section 8.8. Registering and Unregistering Devices Section 8.9. Device Registration Section 8.10. Device Unregistration Section 8.11. Enabling and Disabling a Network Device 网络设备的使能与去使能 Section 8.12. Updating the Device Queuing Discipline State 更新设备的？？ Section 8.13. Configuring Device-Related Information from User Space 从用户空间配置与设备相关的信息 Section 8.14. Virtual Devices Section 8.15. Locking 查找 Section 8.16. Tuning via /proc Filesystem Section 8.17. Functions and Variables Featured in This Chapter Section 8.18. Files and Directories Featured in This Chapter Part III: Transmission and Reception 传输与接收 Chapter 9. Interrupts and Network Drivers 网络设备的中断 Section 9.1. Decisions and Traffic Direction 数据流的方向与决策 Section 9.2. Notifying Drivers When Frames Are Received 在数据帧接收到时通知驱动 Section 9.3. Interrupt Handlers 中断处理 Section 9.4. softnet_data Structure XX数据结构 Chapter 10. Frame Reception 帧接收 Section 10.1. Interactions with Other Features 与其它特性交互 Section 10.2. Enabling and Disabling a Device 设备的使能与去使能 Section 10.3. Queues 队列 Section 10.4. Notifying the Kernel of Frame Reception: NAPI and netif_rx 帧接收时通知内核 Section 10.5. Old Interface Between Device Drivers and Kernel: First Part of netif_rx 内核到设备驱动之间的老的接口 Section 10.6. Congestion Management 阻塞管理 Section 10.7. Processing the NET_RX_SOFTIRQ: net_rx_action Chapter 11. Frame Transmission 帧传输 Section 11.1. Enabling and Disabling Transmissions Chapter 12. General and Reference Material About Interrupts 中断的常识和和参考 Section 12.1. Statistics 统计 Section 12.2. Tuning via /proc and sysfs Filesystems Section 12.3. Functions and Variables Featured in This Part of the Book Section 12.4. Files and Directories Featured in This Part of the Book Chapter 13. Protocol Handlers 协议处理 Section 13.1. Overview of Network Stack Section 13.2. Executing the Right Protocol Handler Section 13.3. Protocol Handler Organization Section 13.4. Protocol Handler Registration Section 13.5. Ethernet Versus IEEE 802.3 Frames Section 13.6. Tuning via /proc Filesystem Section 13.7. Functions and Variables Featured in This Chapter Section 13.8. Files and Directories Featured in This Chapter Part IV: Bridging 网桥 Chapter 14. Bridging: Concepts Section 14.1. Repeaters, Bridges, and Routers 中继器，网桥和路由器 Section 14.2. Bridges Versus Switches 网桥与交换机 Section 14.3. Hosts 服务器 Section 14.4. Merging LANs with Bridges 聚合LAN和网桥 Section 14.5. Bridging Different LAN Technologies Section 14.6. Address Learning 寻址 Section 14.7. Multiple Bridges 多网桥 Chapter 15. Bridging: The Spanning Tree Protocol 网桥，生成树协议 Section 15.1. Basic Terminology 基础技术 Section 15.2. Example of Hierarchical Switched L2 Topology 分级交换机的二层拓扑示例 Section 15.3. Basic Elements of the Spanning Tree Protocol 生成树协议的基本元素 Section 15.4. Bridge and Port IDs 网桥和端口ID Section 15.5. Bridge Protocol Data Units (BPDUs) 交换机协议数据单元 Section 15.6. Defining the Active Topology Section 15.7. Timers 计时器 Section 15.8. Topology Changes Section 15.9. BPDU Encapsulation Section 15.10. Transmitting Configuration BPDUs Section 15.11. Processing Ingress Frames Section 15.12. Convergence Time 时间收敛 Section 15.13. Overview of Newer Spanning Tree Protocols Chapter 16. Bridging: Linux Implementation 桥接：Linux的实现 Section 16.1. Bridge Device Abstraction Section 16.2. Important Data Structures Section 16.3. Initialization of Bridging Code Section 16.4. Creating Bridge Devices and Bridge Ports Section 16.5. Creating a New Bridge Device Section 16.6. Bridge Device Setup Routine Section 16.7. Deleting a Bridge Section 16.8. Adding Ports to a Bridge Section 16.9. Enabling and Disabling a Bridge Device Section 16.10. Enabling and Disabling a Bridge Port Section 16.11. Changing State on a Bridge Port Section 16.12. The Big Picture Section 16.13. Forwarding Database Section 16.14. Handling Ingress Traffic Section 16.15. Transmitting on a Bridge Device Section 16.16. Spanning Tree Protocol (STP) Section 16.17. netdevice Notification Chain Chapter 17. Bridging: Miscellaneous Topics 桥接：其它的主题 Section 17.1. User-Space Configuration Tools Section 17.2. Tuning via /proc Filesystem Section 17.3. Tuning via /sys Filesystem Section 17.4. Statistics Section 17.5. Data Structures Featured in This Part of the Book Section 17.6. Functions and Variables Featured in This Part of the Book Section 17.7. Files and Directories Featured in This Part of the Book Part V: Internet Protocol Version 4 (IPv4) IP协议(V4) Chapter 18. Internet Protocol Version 4 (IPv4): Concepts Section 18.1. IP Protocol: The Big Picture Section 18.2. IP Header Section 18.3. IP Options Section 18.4. Packet Fragmentation/Defragmentation Section 18.5. Checksums Chapter 19. Internet Protocol Version 4 (IPv4): Linux Foundations and Features Section 19.1. Main IPv4 Data Structures Section 19.2. General Packet Handling Section 19.3. IP Options Chapter 20. Internet Protocol Version 4 (IPv4): Forwarding and Local Delivery Section 20.1. Forwarding Section 20.2. Local Delivery Chapter 21. Internet Protocol Version 4 (IPv4): Transmission Section 21.1. Key Functions That Perform Transmission Section 21.2. Interface to the Neighboring Subsystem Chapter 22. Internet Protocol Version 4 (IPv4): Handling Fragmentation Section 22.1. IP Fragmentation Section 22.2. IP Defragmentation Chapter 23. Internet Protocol Version 4 (IPv4): Miscellaneous Topics Section 23.1. Long-Living IP Peer Information Section 23.2. Selecting the IP Header's ID Field Section 23.3. IP Statistics Section 23.4. IP Configuration Section 23.5. IP-over-IP Section 23.6. IPv4: What's Wrong with It? Section 23.7. Tuning via /proc Filesystem Section 23.8. Data Structures Featured in This Part of the Book Section 23.9. Functions and Variables Featured in This Part of the Book Section 23.10. Files and Directories Featured in This Part of the Book Chapter 24. Layer Four Protocol and Raw IP Handling Section 24.1. Available L4 Protocols Section 24.2. L4 Protocol Registration Section 24.3. L3 to L4 Delivery: ip_local_deliver_finish Section 24.4. IPv4 Versus IPv6 Section 24.5. Tuning via /proc Filesystem Section 24.6. Functions and Variables Featured in This Chapter Section 24.7. Files and Directories Featured in This Chapter Chapter 25. Internet Control Message Protocol (ICMPv4) Section 25.1. ICMP Header Section 25.2. ICMP Payload Section 25.3. ICMP Types Section 25.4. Applications of the ICMP Protocol Section 25.5. The Big Picture Section 25.6. Protocol Initialization Section 25.7. Data Structures Featured in This Chapter Section 25.8. Transmitting ICMP Messages Section 25.9. ICMP Statistics Section 25.10. Passing Error Notifications to the Transport Layer Section 25.11. Tuning via /proc Filesystem Section 25.12. Functions and Variables Featured in This Chapter Section 25.13. Files and Directories Featured in This Chapter Part VI: Neighboring Subsystem Chapter 26. Neighboring Subsystem: Concepts Section 26.1. What Is a Neighbor? Section 26.2. Reasons That Neighboring Protocols Are Needed Section 26.3. Linux Implementation Section 26.4. Proxying the Neighboring Protocol Section 26.5. When Solicitation Requests Are Transmitted and Processed Section 26.6. Neighbor States and Network Unreachability Detection (NUD) Chapter 27. Neighboring Subsystem: Infrastructure Section 27.1. Main Data Structures Section 27.2. Common Interface Between L3 Protocols and Neighboring Protocols Section 27.3. General Tasks of the Neighboring Infrastructure Section 27.4. Reference Counts on neighbour Structures Section 27.5. Creating a neighbour Entry Section 27.6. Neighbor Deletion Section 27.7. Acting As a Proxy Section 27.8. L2 Header Caching Section 27.9. Protocol Initialization and Cleanup Section 27.10. Interaction with Other Subsystems Section 27.11. Interaction Between Neighboring Protocols and L3 Transmission Functions Section 27.12. Queuing Chapter 28. Neighboring Subsystem: Address Resolution Protocol (ARP) Section 28.1. ARP Packet Format Section 28.2. Example of an ARP Transaction Section 28.3. Gratuitous ARP Section 28.4. Responding from Multiple Interfaces Section 28.5. Tunable ARP Options Section 28.6. ARP Protocol Initialization Section 28.7. Initialization of a neighbour Structure Section 28.8. Transmitting and Receiving ARP Packets Section 28.9. Processing Ingress ARP Packets Section 28.10. Proxy ARP Section 28.11. Examples Section 28.12. External Events Section 28.13. ARPD Section 28.14. Reverse Address Resolution Protocol (RARP) Section 28.15. Improvements in ND (IPv6) over ARP (IPv4) Chapter 29. Neighboring Subsystem: Miscellaneous Topics Section 29.1. System Administration of Neighbors Section 29.2. Tuning via /proc Filesystem Section 29.3. Data Structures Featured in This Part of the Book Section 29.4. Files and Directories Featured in This Part of the Book Part VII: Routing Chapter 30. Routing: Concepts Section 30.1. Routers, Routes, and Routing Tables Section 30.2. Essential Elements of Routing Section 30.3. Routing Table Section 30.4. Lookups Section 30.5. Packet Reception Versus Packet Transmission Chapter 31. Routing: Advanced Section 31.1. Concepts Behind Policy Routing Section 31.2. Concepts Behind Multipath Routing Section 31.3. Interactions with Other Kernel Subsystems Section 31.4. Routing Protocol Daemons Section 31.5. Verbose Monitoring Section 31.6. ICMP_REDIRECT Messages Section 31.7. Reverse Path Filtering Chapter 32. Routing: Li nux Implementation Section 32.1. Kernel Options Section 32.2. Main Data Structures Section 32.3. Route and Address Scopes Section 32.4. Primary and Secondary IP Addresses Section 32.5. Generic Helper Routines and Macros Section 32.6. Global Locks Section 32.7. Routing Subsystem Initialization Section 32.8. External Events Section 32.9. Interactions with Other Subsystems Chapter 33. Routing: The Routing Cache Section 33.1. Routing Cache Initialization Section 33.2. Hash Table Organization Section 33.3. Major Cache Operations Section 33.4. Multipath Caching Section 33.5. Interface Between the DST and Calling Protocols Section 33.6. Flushing the Routing Cache Section 33.7. Garbage Collection Section 33.8. Egress ICMP REDIRECT Rate Limiting Chapter 34. Routing: Routing Tables Section 34.1. Organization of Routing Hash Tables Section 34.2. Routing Table Initialization Section 34.3. Adding and Removing Routes Section 34.4. Policy Routing and Its Effects on Routing Table Definitions Chapter 35. Routing: Lookups Section 35.1. High-Level View of Lookup Functions Section 35.2. Helper Routines Section 35.3. The Table Lookup: fn_hash_lookup Section 35.4. fib_lookup Function Section 35.5. Setting Functions for Reception and Transmission Section 35.6. General Structure of the Input and Output Routing Routines Section 35.7. Input Routing Section 35.8. Output Routing Section 35.9. Effects of Multipath on Next Hop Selection Section 35.10. Policy Routing Section 35.11. Source Routing Section 35.12. Policy Routing and Routing Table Based Classifier Chapter 36. Routing: Miscellaneous Topics Section 36.1. User-Space Configuration Tools Section 36.2. Statistics Section 36.3. Tuning via /proc Filesystem Section 36.4. Enabling and Disabling Forwarding Section 36.5. Data Structures Featured in This Part of the Book Section 36.6. Functions and Variables Featured in This Part of the Book Section 36.7. Files and Directories Featured in This Part of the Book About the Authors Colophon Index