Preface -- Acknowledgments -- 1. INTRODUCTION -- 1.1 Overview of TCP/IP Stack -- 1.2 Source Code Organization for Linux 2.4.20 -- 1.3 TCP/IP Stack and Kernel Control Paths -- 1.4 Linux Kernel Until Version 2.4 Is Non-preemptible -- 1.5 Linux Process and Thread -- 1.6 Kernel Synchronization Mechanism -- 1.7 Application Interfaces for TCP/IP Programming -- 1.8 Shutdown -- 1.9 I/O -- 1.10 TCP State -- 1.11 Summary -- 2. PROTOCOL FUNDAMENTALS -- 2.1 TCP -- 2.2 TCP Options (RFC 1323) -- 2.3 TCP Data Flow -- 2.4 Delayed Acknowledgment -- 2.5 Nagle's Algorithm (RFC 896) -- 2.6 TCP Sliding Window Protocol -- 2.7 Maximizing TCP Throughput -- 2.8 TCP Timers -- 2.9 TCP Congestion Control -- 2.10 TCP Performance and Reliability -- 2.11 IP (Internet Protocol) -- 2.12 Routing -- 2.13 netstat -- 2.14 traceroute -- 2.15 ICMP -- 2.16 ping -- 2.17 ARP/RARP -- 2.18 Summary -- 3. KERNEL IMPLEMENTATION OF SOCKETS -- 3.1 Socket Layer -- 3.2 VFS and Socket -- 3.3 Protocol Socket Registration -- 3.4 struct inet_protosw -- 3.5 Socket Organization in the Kernel -- 3.6 Socket -- 3.7 inet_create -- 3.8 Flow Diagram for Socket Call -- 3.9 Summary -- 4. KERNEL IMPLEMENTATION OF TCP CONNECTION SETUP -- 4.1 Connection Setup -- 4.2 Bind -- 4.3 Listen -- 4.4 Connection Request Handling by Kernel -- 4.5 Accept -- 4.6 Client Side Setup -- 4.7 Summary -- 5. sk_buff AND PROTOCOL HEADERS -- 5.1 struct sk_buff -- 5.2 struct skb_shared_info -- 5.3 sk_buff and DMA_SKB_FRAG_STRUCT -- 5.4 Routines Operating on sk_buff -- 5.5 sk_buff Builds Protocol Headers as It Traverses Down the Protocol Layers -- -- 5.6 sk_buff Extracts Protocol Headers as It Traverses Up the Protocol Layers When a Packet Arrives -- 5.7 Summary -- 6. MOVEMENT OF sk_buff ACROSS PROTOCOL LAYERS -- 6.1 Packet Traversing Down the TCP/IP Stack -- 6.2 Routed Packet Ready for Transmission -- 6.3 Kernel Flow for a Packet Moving Down the Stack -- 6.4 Packet Traversing Up the TCP/IP Stack -- 6.5 Kernel Flow for a Packet Moving Up the Stack -- 6.6 Summary.

7. TCP SEND -- 7.1 TCP Segmentation Unit for Sending Data -- 7.2 Segmentation with Scatter¿́¿Gather Technique -- 7.3 Sending OOB Data -- 7.4 Flow for TCP Segmentation Unit and Send Process -- 7.5 Functional Level Flow for Segmentation and Send Mechanism -- 7.6 Summary -- 8. TCP RECEIVE -- 8.1 Queuing Mechanism -- 8.2 Processing of TCP Data from the Receive Queue -- -- 8.3 TCP Urgent Byte Processing -- -- 8.4 DATA Flow Diagram for Receiving Data over the TCP Socket -- 8.5 Summary -- 9. TCP MEMORY MANAGEMENT -- 9.1 Transmit Side TCP Memory Management -- 9.2 Receive Side TCP Memory Management -- -- 9.3 Freeing of Memory Allocated to a Receive Buffer -- 9.4 System-Wide Control Parameters Are Worth Noticing When It Comes to TCP Memory Management -- 9.5 Summary -- 10. TCP TIMERS -- 10.2 TCP Retransmit Timer -- 10.3 Zero Window Probe Timer -- -- 10.4 Delay ACK Timer -- -- 10.5 Keepalive Timer -- 10.6 SYN-ACK Timer -- 10.7 TIME_WAIT Timer -- -- 10.7.8 __tcp_tw_hashdance() -- 10.8 Summary -- 11. TCP CORE PROCESSING -- 11.1 TCP Incoming Segment Processing -- 11.2 Fast Path Processing -- 11.3 Slow Path Processing -- 11.4 Processing of Incoming ACK -- -- 11.5 Processing of SACK blocks -- -- 11.6 Reordering Length -- 11.7 Processing TCP Urgent Pointer -- 11.8 Processing Data Segments in Slow Path -- -- 11.9 Overview of Core TCP Processing -- 11.10 Summary -- 12. TCP STATE PROCESSING -- 12.1 Overview of State Processing -- 12.2 TCP States -- 12.3 Processing of Duplicate/Partial ACKs in Recovery State -- -- 12.4 Processing of Duplicate/Partial ACKs in Loss State -- -- 12.5 Default Processing of TCP States -- -- 12.6 Processing of TCP Non-open States when ACKed Beyond tp ¿́¿ high_seq -- -- 12.7 Summary -- 13. NETLINK SOCKETS -- 13.1 Introduction to Netlink Sockets -- 13.2 Netlink Socket Registration and Initialization at Boot Time -- 13.3 How Is the Kernel Netlink Socket Created? -- 13.4 How Is the User Netlink Socket Created? -- 13.5 Netlink Data Structures -- 13.6 Other Important Data Strutures.

13.7 Netlink Packet Format -- 13.8 Netlink Socket Example Command for Adding a qdisc -- 13.9 Flow Diagram for tc Command in Kernel Space -- 13.10 Summary -- 14. IP ROUTING -- 14.1 Routing -- 14.2 Policy-Based Routing -- 14.3 Multipathing -- 14.4 Record Route Options (RFC 791) and Processing by Linux Stack -- 14.5 Source Routing -- 14.6 Linux Kernel Implementation of Routing Table and Caches -- 14.7 Routing Cache Implementation Overview -- 14.8 Managing Routing Cache -- 14.9 Implementation Overview of Forwarding Information Base (FIB) -- -- 14.10 Adding New Entry in Routing Table Using ip Command (RT Netlink Interface) -- -- 14.11 What Happens When the ip Command Is Run with a Rule Option for Adding an Entry in the Routing Table? -- 14.12 FIB Traversal Flow Diagram -- 14.13 Summary -- -- 15. IP QUALITY OF SERVICE IN LINUX (IP QoS) -- 15.1 Introduction -- 15.2 Basic Components of Linux Traffi c Control -- 15.3 Linux Implementation of pfi fo_fast qdisc -- 15.4 Queueing Discipline Data Structure -- 15.5 tc User Program and Kernel Implementation Details -- -- 15.6 The tc Commands for Creating Class Hierarchy for CBQ -- -- 15.7 Filters -- 15.8 u32 Filter Implementation -- -- 15.9 Route Filter Implementation -- -- 15.10 Enqueue -- -- 15.11 Overview of Linux Implementation of CBQ -- 15.12 cbq_dequeue() -- 15.13 Summary -- -- 16. IP FILTER AND FIREWALL -- 16.1 Netfi lter Hook Framework -- 16.2 Netfi lter Hooks on IP Stack -- 16.3 Overview of Netfi lter Hooks on Linux TCP-IP Stack -- 16.4 Registration of Netfi lter Hooks -- 16.5 Processing of Netfi lter Hooks -- 16.6 Compatibility Framework -- 16.7 Ip Chains -- 16.8 How Is the Packet Filtered with Ipchains -- 16.9 Iptables -- 16.10 Iptables Filter Rules and Target Organization -- 16.11 Organization of Filter Rules and Target for Iptables -- 16.12 Filtering Packets with Iptables -- 16.13 Summary -- -- 17. NET SOFTIRQ -- 17.1 Why Net SoftIRQs, and How Do We Raise Them? -- 17.2 How Are SoftIRQs Are Processed, and When? -- 17.3 Registration of SoftIRQs.

17.4 Packet Reception and Delayed Processing by Rx SoftIRQ -- 17.5 Processing of Net Rx SoftIRQ -- 17.6 Packet Transmission and SoftIRQ -- 17.7 Summary -- 18. TRANSMISSION AND RECEPTION OF PACKETS -- 18.1 DMA Ring Buffers for Transmission and Reception of Packets -- 18.2 Packet Reception Process -- 18.3 Packet Transmission Process -- 18.4 Implementation of Reception and Transmission of Packets -- 18.5 Rx Interrupt for Reception of Packets -- 18.6 Transmission of Packets -- 18.7 Summary -- 19. lkcd AND DEBUGGING TCP/IP STACK -- 19.1 lkcd Source and Patches -- 19.2 Touching the Socket -- 19.3 Looking into the Receive Socket Buffer -- 19.3.1 Route Information in sk_buff -- 19.4 Peep into Send Socket Buffer -- 19.5 TCP Segmentation Unit -- 19.6 Send Congestion Window and ssthresh -- 19.7 Retransmissions and Route -- 19.8 Peeping into Connection Queues and SYN Queues -- 19.9 Routing and IP Qos lcrash Steps -- 19.10 CBQ (Class-Based) Queueing Discipline lcrash Steps -- 19.11 U32 Filters -- 19.12 Route Filters -- 19.13 FIB Table lcrash Output for Setting Up the Realm Using ip Command -- 19.14 lcrash Output for Setting Up Route Filter Using tc Command -- 19.15 Netlink Data Structure -- 19.16 Summary -- 20. NEXT EDITION -- Bibliography -- Index.