TCP/IP illustrated

Preface
Chapter 1. Introduction
1.1 Introduction
1.2 Layering
1.3 TCP/IP Layering
1.4 Internet Addresses
1.5 The Domain Name System
1.6 Encapsulation
1.7 Demultiplexing
1.8 Client-Server Model
1.9 Port Numbers
1.10 Standardization Process
1.11 RFCs
1.12 Standard, Simple Services
1.13 The Internet
1.14 Implementations
1.15 Application Programming Interfaces
1.16 Test Network
1.17 Summary

Chapter 2. Link Layer
2.1 Introduction
2.2 Ethernet and IEEE 802 Encapsulation
2.3 Trailer Encapsulation
2.4 SLIP: Serial Line IP
2.5 Compressed SLIP
2.6 PPP: Point-to-Point Protocol
2.7 Loopback Interface
2.8 MTU
2.9 Path MTU
2.10 Serial Line Throughput Calculations
2.11 Summary

Chapter 3. IP: Internet Protocol
3.1 Introduction
3.2 IP Header
3.3 IP Routing
3.4 Subnet Addressing
3.5 Subnet Mask
3.6 Special Case IP Address
3.7 A Subnet Example
3.8 ifconfig Command
3.9 netstat Command
3.10 IP Futures
3.11 Summary

Chapter 4. ARP: Address Resolution Protocol
4.1 Introduction
4.2 An Example
4.3 ARP Cache
4.4 ARP Packet Format
4.5 ARP Examples
4.6 Proxy ARP
4.7 Gratuitous ARP
4.8 arp Command
4.9 Summary

Chapter 5. RARP: Reverse Address Resolution Protocol
5.1 Introduction
5.2 RARP Packet Format
5.3 RARP Examples
5.4 RARP Server design
5.5 Summary

Chapter 6. ICMP: Internet Control Message Protocol
6.1 Introduction
6.2 ICMP Message Types
6.3 ICMP Address Mask Request and Reply
6.4 ICMP Timestamp Request and Reply
6.5 ICMP Port Unreachable Error
6.6 4.4BSD Processing of ICMP Messages
6.7 Summary

Chapter 7. Ping Program
7.1 Introduction
7.2 Ping Program
7.3 IP Record Route Option
7.4 IP Timestamp Option
7.5 Summary

Chapter 8. Traceroute Program
8.1 Introduction
8.2 Traceroute Program operation
8.3 LAN output
8.4 WAN output
8.5 IP Source Routing Option
8.6 Summary

Chapter 9. IP Routing
9.1 Introduction
9.2 Routing Principles
9.3 ICMP Host and Network Unreachable Errors
9.4 To Forward or Not to Forward
9.5 ICMP Redirect Errors
9.6 ICMP Router Discovery Messages
9.7 Summary

Chapter 10. Dynamic Routing Protocols
10.1 Introduction
10.2 Dynamic Routing
10.3 Unix Routing Daemons
10.4 RIP: Routing Information Protocol
10.5 RIP Version 2
10.6 OSPF: Open Shortest Path First
10.7 BGP: Border Gateway Protocol
10.8 CIDR: Classless Interdomain Routing
10.9 Summary

Chapter 11. UDP: User Datagram Protocol
11.1 Introduction
11.2 UDP Header
11.3 UDP Checksum
11.4 A Simple Example
11.5 IP Fragmentation
11.6 ICMP Unreachable Error (Fragmentation Required)
11.7 Determining the Path MTU Using Traceroute
11.8 Path MTU Discovery with UDP
11.9 Interaction Between UDP and ARP
11.10 Maximum UDP Datagram Size
11.11 ICMP Source Quench Error
11.12 UDP Server Design
11.13 Summary

Chapter 12. Broadcasting and Multicasting
12.1 Introduction
12.2 Broadcasting
12.3 Broadcasting Examples
12.4 Multicasting
12.5 Summary

Chapter 13. IGMP: Internet Group Management Protocol
13.1 Introduction
13.2 IGMP Message
13.3 IGMP Protocol
13.4 An Example
13.5 Summary

Chapter 14. DNS: The Domain Name System
14.1 Introduction
14.2 DNS Basics
14.3 DNS Message Format
14.4 A Simple Example
14.5 Pointer Quiries
14.6 Resourse Records
14.7 Caching
14.8 UDP or TCP
14.9 Another Example
14.10 Summary

Chapter 15. TFTP: Trivial File Transfer Protocol
15.1 Introduction
15.2 Protocol
15.3 An Example
15.4 Security
15.5 Summary

Chapter 16. BOOTP: Bootstrap Protocol
16.1 Introduction
16.2 BOOTP Packet Format
16.3 An Example
16.4 BOOTP Server Design
16.5 BOOTP Through a Router
16.6 Vendor-Specific Information
16.7 Summary

Chapter 17. TCP: Transmission Control Protocol
17.1 Introduction
17.2 TCP Services
17.3 TCP Header
17.4 Summary

Chapter 18. TCP Connection Establishment and Termination
18.1 Introduction
18.2 Connection Establishment and Termination
18.3 Timeout of Connection Establishment
18.4 Maximum Segment Size
18.5 TCP Half-Close
18.6 TCP State Transition Diagram
18.7 Reset Segments
18.8 Simultaneous Open
18.9 Simultaneous Close
18.10 TCP Options
18.11 TCP Server Design
18.12 Summary

Chapter 19. TCP Interactive Data Flow
19.1 Introduction
19.2 Interactive Input
19.3 Delayed Acknoledgements
19.4 Nagle Algorithm
19.5 Windows Size Advertisments
19.6 Summary

Chapter 20. TCP Bulk Data Flow
20.1 Introduction
20.2 Normal Data Flow
20.3 Sliding Windows
20.4 Window Size
20.5 PUSH Flag
20.6 Slow Start
20.7 Bulk Data Throughput
20.8 Urgent Mode
20.9 Summary

Chapter 21. TCP Timeout and Retransmission
21.1 Introduction
21.2 Simple Timeout and Retransmission Example
21.3 Round-Trip Time Measurement
21.4 An RTT Example
21.5 Congestion Example
21.6 Congestion Avoidance Algorithm
21.7 Fast Retransmit and Fast Recovery Algorithm
21.8 Congestion Example (Continued)
21.9 Per-Route Metrics
21.10 ICMP Errors
21.11 Repacketization
21.12 Summary

Chapter 22. TCP Persist Timer
22.1 Introduction
22.2 An Example
22.3 Silly Windows Syndrome
22.4 Summary

Chapter 23. TCP Keepalive Timer
23.1 Introduction
23.2 Description
23.3 Keepalive Examples
23.4 Summary

Chapter 24. TCP Futures and Performance
24.1 Introduction
24.2 Path MTU Discovery
24.3 Long Fat Pipes
24.4 Windows Scale Option
24.5 Timestamp Option
24.6 PAWS: Protection Against Wrapped Sequence Numbers
24.7 T/TCP: A TCP Extension for Transactions
24.8 TCP Performance
24.9 Summary

Chapter 25. SNMP: Simple Network Management Protocol
25.1 Introduction
25.2 Protocol
25.3 Structure of Management Information
25.4 Object Identifiers
25.5 Introduction to the Management Information Base
25.6 Instance Identification
25.7 Simple Examples
25.8 Management Information Base (Continued)
25.9 Additional Examples
25.10 Traps
25.11 ASN.1 and BER
25.12 SNMP Version 2
25.13 Summary

Chapter 26. Telnet and Rlogin: Remote Login
26.1 Introduction
26.2 Rlogin Protocol
26.3 Rlogin Examples
26.4 Telnet Protocol
26.5 Telnet Examples
26.6 Summary

Chapter 27. FTP: File Transfer Protocol
27.1 Introduction
27.2 FTP Protocol
27.3 FTP Examples
27.4 Summary

Chapter 28. SMTP: Simple Mail Transfer Protocol
28.1 Introduction
28.2 SMTP Protocol
28.3 SMTP Examples
28.4 SMTP Futures
28.5 Summary

Chapter 29. NFS: Network File System
29.1 Introduction
29.2 Sun Remote Procedure Call
29.3 XDR: External Data Representation
29.4 Port Mapper
29.5 NFS Protocol
29.6 NFS Examples
29.7 NFS Version 3
29.8 Summary

Chapter 30. Other TCP/IP Applications
30.1 Introduction
30.2 Finger Protocol
30.3 Whois Protocol
30.4 Archie, WAIS, Gopher, Veronica and WWW
30.5 X Window System
30.6 Summary

1. Introduction
Introduction
Source Code Presentation
History
Application Programming Interfaces
Example Program
System Calls and Library Functions
Network Implementation Overview
Descriptors
Mbufs (Memory Buffers) and Output Processing
Input Processing
Network Implementation Overview Revisited
Interrupt Levels and Concurrency
Source Code Organization
Test Network
Summary

2. Mbufs: Memory Buffers
    Introduction
Code Introduction
Mbuf Definitions
mbuf Structure
Simple Mbuf Macros and Functions
m_devget and m_pullup Functions
Summary of Mbuf Macros and Functions
Summary of Net/3 Networking Data Structures
m_copy and Cluster Reference Counts
Alternatives
Summary

3. Interface Layer
Introduction
Code Introduction
ifnet Structure
ifaddr Structure
sockaddr Structure
ifnet and ifaddr Specialization
Network Initialization Overview
Ethernet Initialization
SLIP Initialization
Loopback Initialization
if_attach Function
ifinit Function
Summary

4. Interfaces: Ethernet
Introduction
Code Introduction
Ethernet Interface
ioctl System Call
Summary

5. Interfaces: SLIP and Loopback
Introduction
Code Introduction
SLIP Interface
Loopback Interface 
Summary     

6. IP Addressing
Introduction
Code Introduction
Interface and Address Summary
sockaddr_in Structure
in_ifaddr Structure
Address Assignment
Interface ioctl Processing
Internet Utility Functions
ifnet Utility Functions
Summary    

7. Domains and Protocols
Introduction
Code Introduction
domain Structure
protosw Structure
IP domain and protosw Structures
pffindproto and pffindtype Functions
pfctlinput Function
IP Initialization
sysctl System Call
Summary    

8. IP: Internet Protocol
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    

9. IP Option Processing
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    

10. IP Fragmentation and Reassembly
Introduction
Code Introduction
Fragmentation
ip_optcopy Function
Reassembly
ip_reass Function
ip_slowtimo Function
Summary    

11. ICMP: Internet Control Message Protocol
Introduction
Code Introduction
icmp Structure
ICMP protosw Structure
Input Processing: icmp_input Function
Error Processing
Request Processing
Redirect Processing
Reply Processing
Output Processing
icmp_error Function
icmp_reflect Function
icmp_send Function
icmp_sysctl Function
Summary    

12. IP Multicasting
Introduction
Code Introduction
Ethernet Multicast Addresses
ether_multi Structure
Ethernet Multicast Reception
in_multi Structure
ip_moptions Structure
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    

13. IGMP: Internet Group Management Protocol
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    

14. IP Multicast Routing
Introduction
Code Introduction
Multicast Output Processing Revisited
mrouted Daemon
Virtual Interfaces
IGMP Revisited
Multicast Routing
Multicast Forwarding: ip_mforward Function
Cleanup: ip_mrouter_done Function
Summary    

15. Socket Layer
Introduction
Code Introduction
socket Structure
System Calls
Processes, Descriptors, and Sockets
socket System Call
getsock 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    

16. Socket I/O
Introduction
Code Introduction
Socket Buffers
write, writev, sendto, and sendmsg System Calls
sendmsg System Call
sendit Function
sosend Function
read, readv, recvfrom, and recvmsg System Calls
recvmsg System Call
recvit Function
soreceive Function
soreceive Code
select System Call
Summary    

17. Socket Options
Introduction
Code Introduction
setsockopt System Call
getsockopt System Call
fcntl and ioctl System Calls
getsockname System Call
getpeername System Call
Summary    

18. Radix Tree Routing Tables
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    

19. Routing Requests and Routing Messages
Introduction
rtalloc and rtalloc1 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_msg1 Function
rt_msg2 Function
sysctl_rtable Function
sysctl_dumpentry Function
sysctl_iflist Function
Summary    

20. Routing Sockets
Introduction
routedomain and protosw Structures
Routing Control Blocks
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    

21. ARP: Address Resolution Protocol
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
arp_rtrequest Function
ARP and Multicasting
Summary    

22. Protocol Control Blocks
Introduction
Code Introduction
inpcb Structure
in_pcballoc and in_pcbdetach Functions
Binding, Connecting, and Demultiplexing
in_pcblookup Function
in_pcbbind Function
in_pcbconnect Function
in_pcbdisconnect Function
in_setsockaddr and in_setpeeraddr Functions
in_pcbnotify, in_rtchange, and in_losing Functions
Implementation Refinements
Summary    

23. UDP: User Datagram Protocol
Introduction
Code Introduction
UDP protosw Structure
UDP Header
udp_init Function
udp_output Function
udp_input Function
udp_saveopt Function
udp_ctlinput Function
udp_usrreq Function
udp_sysctl Function
Implementation Refinements
Summary    

24. TCP: Transmission Control Protocol
Introduction
Code Introduction
TCP protosw Structure
TCP Header
TCP Control Block
TCP State Transition Diagram
TCP Sequence Numbers
tcp_init Function
Summary    

25. TCP Timers
Introduction
Code Introduction
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    

26. TCP Output
Introduction
tcp_output Overview
Determine if a Segment Should be Sent
TCP Options
Window Scale Option
Timestamp Option
Send a Segment
tcp_template Function
tcp_respond Function
Summary    

27. TCP Functions
Introduction
tcp_drain Function
tcp_drop Function
tcp_close Function
tcp_mss Function
tcp_ctlinput Function
tcp_notify Function
tcp_quench Function
TCP_REASS Macro and tcp_reass Function
tcp_trace Function
Summary    

28. TCP Input
Introduction
Preliminary Processing
tcp_dooptions Function
Header Prediction
TCP Input: Slow Path Processing
Initation of Passive Open or Active Open
PAWS: Protection Against Wrapped Sequence Numbers
Trim Segment so Data is Within Window
Self-Connects and Simultaneous Opens
Record Timestamp
RST Processing
Summary    

29. TCP Input (Continued)
Introduction
ACK Processing Overview
Completion of Passive Opens and Simultaneous Opens
Fast Retransmit and Fast Recovery Algorithms
ACK Processing
Update Window Information
Urgent Mode Processing
tcp_pulloutofband Function
Processing of Received Data
FIN Processing
Final Processing
Implementation Refinements
Header Compression
Summary    

30. TCP User Requests
Introduction
tcp_usrreq Function
tcp_attach Function
tcp_disconnect Function
tcp_usrclosed Function
tcp_ctloutput Function
Summary    

31. BPF: BSD Packet Filter
Introduction
Code Introduction
bpf_if Structure
bpf_d Structure
BPF Input
BPF Output
Summary    

32. Raw IP
Introduction
Code Introduction
Raw IP protosw Structure
rip_init Function
rip_input Function
rip_output Function
rip_usrreq Function
rip_ctloutput Function
Summary    

Epilogue

Appendix A. Solutions to Selected Exercises

Appendix B. Source Code Availability

Appendix C. RFC 1122 Compliance
Link-Layer Requirements
IP Requirements
IP Options Requirements
IP Fragmentation and Reassembly Requirements
ICMP Requirements
Multicasting Requirements
IGMP Requirements
Routing Requirements
ARP Requirements
UDP Requirements
TCP Requirements

Bibliography

Index

Part I.    TCP for Transactions     

 1.  T/TCP Introduction    
     1.1   Introduction   
     1.2   UDP Client-Server  
     1.3   TCP Client-Server   
     1.4   T/TCP Client-Server   
     1.5   Test Network   
     1.6   Timing Example   
     1.7   Applications   
     1.8   History   
     1.9   Implementations   
     1.10  Summary   

2.  T/TCP Protocol    
     2.1   Introduction  
     2.2   New TCP Options for T/TCP  
     2.3   T/TCP Implementation Variables   
     2.4   State Transition Diagram 
     2.5   T/TCP Extended States   
     2.6   Summary  

3.  T/TCP Examples   
     3.1   Introduction   
     3.2   Client Reboot   
     3.3   Normal T/TCP Transaction  
     3.4   Server Receives Old Duplicate SYN   
     3.5   Server Reboot   
     3.6   Request or Reply Exceeds MSS   
     3.7   Backward Compatibility   
     3.8   Summary  

4.  T/TCP Protocol (Continued)    
     4.1   Introduction  
     4.2   Client Port Numbers and TIME_WAIT State  
     4.3   Purpose of the TIME_WAIT State   
     4.4   TIME_WAIT State Truncation  
     4.5   Avoiding the Three-Way Handshake with TAO 
     4.6   Summary   

5.  T/TCP Implementation: Socket Layer  
     5.1   Introduction   
     5.2   Constants  
     5.3   sosend Function   
     5.4   Summary   

6.  T/TCP Implementation: Routing Table    
     6.1   Introduction   
     6.2   Code Introduction   
     6.3   radix_node_head Structure   
     6.4   rtentry Structure   
     6.5   rt_metrics Structure   
     6.6   in_inithead Function  
     6.7   in_addroute Function   
     6.8   in_matroute Function   
     6.9   in_clsroute Function   
     6.10  in_rtqtimo Function  
     6.11  in_rtqkill Function  
     6.12  Summary  

7.  T/TCP Implementation: Protocol Control Blocks 
     7.1   Introduction  
     7.2   in_pcbladdr Function   
     7.3   in_pcbconnect Function   
     7.4   Summary   

8.  T/TCP Implementation: TCP Overview  
     8.1   Introduction   
     8.2   Code Introduction   
     8.3   TCP protosw Structure   
     8.4   TCP Control Block 
     8.5   tcp_init Function   
     8.6   tcp_slowtimo Function   
     8.7   Summary   

9.  T/TCP Implementation: TCP Output   
     9.1   Introduction   
     9.2   tcp_output Function  
     9.3   Summary   

10.  T/TCP Implementation: TCP Functions   
     10.1   Introduction   
     10.2   tcp_newtcpcb Function   
     10.3   tcp_rtlookup Function   
     10.4   tcp_gettaocache Function   
     10.5   Retransmission Timeout Calculations   
     10.6   tcp_close Function   
     10.7   tcp_msssend Function   
     10.8   tcp_mssrcvd Function   
     10.9   tcp_dooptions Function   
     10.10  tcp_reass Function   
     10.11  Summary   

11.  T/TCP Implementation: TCP Input  
     11.1   Introduction   
     11.2   Preliminary Processing   
     11.3   Header Prediction   
     11.4   Initiation of Passive Open   
     11.5   Initiation of Active Open   
     11.6   PAWS: Protection Against Wrapped Sequence Numbers   
     11.7   ACK Processing   
     11.8   Completion of Passive Opens and Simultaneous Opens   
     11.9   ACK Processing (Continued)   
     11.10  FIN Processing   
     11.11  Summary   

12.  T/TCP Implementation: TCP User Requests   
     12.1   Introduction 
     12.2   PRU_CONNECT Request   
     12.3   tcp_connect Function   
     12.4   PRU_SEND and PRU_SEND_EOF Requests   
     12.5   tcp_usrclosed Function   
     12.6   tcp_sysctl Function   
     12.7   T/TCP Futures   
     12.8   Summary   

Part II.    Additional TCP Applications   

13.  HTTP: Hypertext Transfer Protocol 
     13.1   Introduction   
     13.2   Introduction to HTTP and HTML   
     13.3   HTTP Protocol   
     13.4   An Example   
     13.5   HTTP Statistics   
     13.6   Performance Problems   
     13.7   Summary   

14.  Packets Found on an HTTP Server   
     14.1   Introduction   
     14.2   Multiple HTTP Servers   
     14.3   Client SYN Interarrival Time   
     14.4   RTT Measurements   
     14.5   listen Backlog Queue
     14.6   Client SYN Options  
     14.7   Client SYN Retransmissions   
     14.8   Domain Names   
     14.9   Timing Out Persist Probes   
     14.10  Simulation of T/TCP Routing Table Size   
     14.11  Mbuf Interaction   
     14.12  TCP PCB Cache and Header Prediction   
     14.13  Summary   

15.  NNTP: Network News Transfer Protocol   
     15.1   Introduction   
     15.2   NNTP Protocol   
     15.3   A Simple News Client   
     15.4   A More Sophisticated News Client   
     15.5   NNTP Statistics   
     15.6   Summary  

Part III.    The Unix Domain Protocols   

16.  Unix Domain Protocols: Introduction   
     16.1   Introduction   
     16.2   Usage   
     16.3   Performance   
     16.4   Coding Examples   
     16.5   Summary   

17.  Unix Domain Protocols: Implementation   
     17.1   Introduction  
     17.2   Code Introduction   
     17.3   Unix domain and protosw Structures   
     17.4   Unix Domain Socket Address Structures   
     17.5   Unix Domain Protocol Control Blocks   
     17.6   uipc_usrreq Function   
     17.7   PRU_ATTACH Request and unp_attach Function   
     17.8   PRU_DETACH Request and unp_detach Function   
     17.9   PRU_BIND Request and unp_bind Function   
     17.10  PRU_CONNECT Request and unp_connect Function   
     17.11  PRU_CONNECT2 Request and unp_connect2 Function  
     17.12  socketpair System Call  
     17.13  pipe System Call  
     17.14  PRU_ACCEPT Request   
     17.15  PRU_DISCONNECT Request and unp_disconnect Function   
     17.16  PRU_SHUTDOWN Request and unp_shutdown Function   
     17.17  PRU_ABORT Request and unp_drop Function   
     17.18  Miscellaneous Requests  
     17.19  Summary  

 18.  Unix Domain Protocols: I/O and Descriptor Passing
     18.1   Introduction   
     18.2   PRU_SEND and PRU_RCVD Requests  
     18.3   Descriptor Passing   
     18.4   unp_internalize Function   
     18.5   unp_externalize Function  
     18.6   unp_discard Function 
     18.7   unp_dispose Function   
     18.8   unp_scan Function  
     18.9   unp_gc Function   
     18.10  unp_mark Function   
     18.11  Performance (Revisited)   
     18.12  Summary   


Appendix A.  Measuring Network Times   
     A.1  RTT Measurements Using Ping   
     A.2  Protocol Stack Measurements  
     A.3  Latency and Bandwidth   

Appendix B.  Coding Applications for T/TCP   

Bibliography   

Index