本书全面讲解IPv6及相关协议实现的事实标准KAME，揭示了KAME IPv6协议栈的所有细节，对每行代码到底做了什么以及为什么要这样设计都进行了解释。全书共分7章，分别介绍IPv6地址结构、IPv6、ICMPv6、邻居发现和无状态地址自动配置、传输层协议及套接字API扩展。每章都包含两个主要部分：第一部分提供了作为RFC发布的主要协议规范的摘要，定义各种协议分组，解释每个分组中每个字段的含义和目的；第二部分则描述实现这些RFC的KAME的数据结构及功能。书的最后还提供了一些例子，说明如何编写既可以在IPv4网络上运行、又可以在IPv6网络上运行的可移植应用程序。

本书是IPv6的权威参考书，适合网络设计和开发人员阅读。此外，本书还适合作为高校相关专业网络课程的教学参考书。

1　Introduction　1

1.1　Introduction　1

1.2　A Brief History of IPv6 and KAME　1

1.2.1　Commercial Success of KAME　6

1.3　Overview of the KAME Distribution　6

1.3.1　Source Tree Structure　7

1.3.2　Build Procedure　7

1.4　Overview of BSD Network Implementation　11

1.5　Source Code Narrations　14

1.5.1　Typographical Conventions　14

1.5.2　Sample Source Code Description　15

1.5.3　Preprocessor Variables　16

1.5.4　Networking Device and Architecture Assumptions　17

1.6　Mbufs and IPv6　17

1.6.1　Common Mbuf Manipulation Macros and Functions　20

1.6.2　Mbuf Tagging　20

1.6.3　Mbuf Requirement for IPv6　24

1.6.4　Diagnosing Mbuf Chain　26

2　IPv6 Addressing Architecture　29

2.1　Introduction　29

2.2　IPv6 Addresses　30

2.3　Textual Representation of IPv6 Addresses　31

2.4　Address Scopes　33

2.4.1　Scope Zones　34

2.4.2　Zone Indices　36

2.4.3　Textual Representation of Scoped Addresses　38

2.4.4　Deprecation of Unicast Site-local Addresses　39

2.5　IPv6 Address Format　40

2.5.1　Interface Identifier Generation　42

2.5.2　Notes about Address Format　43

2.5.3　Multicast Address Format　44

2.6　Node Address Requirements　46

2.7　IPv6 Address Space Management　47

2.8　Code Introduction　47

2.8.1　IPv6 Address Structures—in6_addr{} and sockaddr_in6{}　48

2.8.2　Macros and Variables　49

2.9　Handling Scope Zones　51

2.9.1　Initialization of Scope Zones　52

2.9.2　Scope Zone IDs　53

2.9.3　Zone IDs in Address Structures　54

2.9.4　Scope-Related Utility Functions　57

2.10　Interface Address Structures　64

2.10.1　ifaddr{} and in6_ifaddr{} Structures　64

2.10.2　in6_ifreq{} and in6_aliasreq{} Structures　67

2.10.3　Multicast Address Structures　68

2.11　IPv6 Prefix Structure　70

2.12　Overview of Address Manipulation Routines　73

2.13　Interface Initialization for IPv6　76

2.13.1　in6_if_up() Function　76

2.13.2　in6_ifattach() Function　78

2.13.3　in6_ifattach_loopback() Function　81

2.13.4　in6_ifattach_linklocal() Function　82

2.13.5　get_ifid() Function　87

2.13.6　get_hw_ifid() Function　89

2.13.7　get_rand_ifid() Function　93

2.13.8　in6if_do_dad() Function　94

2.14　IPv6 Interface Address Configuration　95

2.14.1　in6_control() Function　95

2.14.2　in6_update_ifa() Function　101

2.14.3　in6_joingroup() and in6_leavegroup() Functions　115

2.14.4　in6_addmulti() and in6_delmulti() Functions　116

2.14.5　in6_ifinit() Function　118

2.14.6　in6_ifaddloop() and in6_ifloop_request() Functions　120

2.15　Deleting an IPv6 Address　122

2.15.1　in6_purgeaddr() Function　123

2.15.2　in6_ifremloop() Function　124

2.15.3　in6_unlink_ifa() Function　125

2.16　Operation with Address Configuration Utility　127

3　Internet Protocol version 6　131

3.1　Introduction　131

3.2　IPv6 Header Format　132

3.2.1　Comparison to the IPv4 Header　133

3.3　IPv6 Extension Headers　134

3.3.1　Order of Extension Headers　135

3.3.2　Hop-by-Hop Options Header　136

3.3.3　Destination Options Header　137

3.3.4　Routing Header　137

3.3.5　Fragment Header　140

3.3.6　IPv6 Options　142

3.4　Source Address Selection　144

3.4.1　Default Address Selection　144

3.4.2　Source Address Selection　146

3.4.3　Destination Address Selection　148

3.5　Code Introduction　149

3.5.1　Statistics　151

3.5.2　Header Structures　151

3.5.3　ip6protosw{} Structure　157

3.6　IPv6 Packet Address Information in Mbuf　160

3.6.1　ip6_setdstifaddr() Function　162

3.6.2　ip6_getdstifaddr() Function　162

3.6.3　ip6_setpktaddrs() Function　163

3.6.4　ip6_getpktaddrs() Function　164

3.7　Input Processing: ip6_input() Function　164

3.8　Processing Hop-by-Hop Options Header: ip6_hopopts_input() Function　179

3.8.1　Processing Each Option: ip6_process_hopopts() Function　180

3.8.2　Processing Unknown Option: ip6_unknown_opt() Function　184

3.9　Processing Destination Options Header: dest6_input() Function　185

3.10　Reassembling Fragmented Packets　187

3.10.1　Structures for Packet Reassembly　187

3.10.2　frag6_input() Function　190

3.11　Processing Routing Header: route6_input() Function　204

3.12　Forwarding: ip6_forward() Function　209

3.13　Output Processing　219

3.13.1　Source Address Selection—in6_selectsrc() Function　219

3.13.2　Route Selection: ip6_selectroute() Function　234

3.13.3　ip6_output() Function　242

3.13.4　Make Extension Headers: ip6_copyexthdr() Function　276

3.13.5　Split Headers: ip6_splithdr() Function　277

3.13.6　Insert Jumbo Payload Option: ip6_insert_jumboopt() Function　278

3.13.7　Fragmentation: ip6_insertfraghdr() Function　281

3.13.8　Path MTU Determination: ip6_getpmtu() Function　282

3.13.9　Multicast Loopback: ip6_mloopback() Function　285

4　Internet Control Message Protocol for IPv6　287

4.1　Introduction　287

4.2　ICMPv6 Message　288

4.2.1　Destination Unreachable Message　289

4.2.2　Packet Too Big Message　291

4.2.3　Time Exceeded Message　292

4.2.4　Parameter Problem Message　293

4.2.5　Echo Request Message　294

4.2.6　Echo Reply Message　294

4.2.7　ICMPv6 Message Processing Rules　295

4.3　Path MTU Discovery Mechanism　296

4.4　Node Information Query　297

4.4.1　Node Information Message Format　299

4.4.2　NOOP Query　301

4.4.3　Supported Qtypes Query　301

4.4.4　Node Name Query　301

4.4.5　Node Addresses Query　303

4.4.6　IPv4 Addresses Query　304

4.5　Code Introduction　304

4.5.1　Statistics　304

4.5.2　ICMPv6 Header　308

4.6　ICMPv6 Input Processing　308

4.6.1　icmp6_input() Function　310

4.6.2　Notifying Errors: icmp6_notify_error() Function　320

4.7　Path MTU Discovery Implementation　329

4.7.1　icmp6_mtudisc_update() Function　329

4.8　ICMPv6 Output Processing　332

4.8.1　Sending Error: icmp6_error() Function　333

4.8.2　Error Rate Limitation: icmp6_ratelimit() Function　341

4.8.3　icmp6_reflect() Function　342

4.9　Node Information Query Implementation　348

4.9.1　Types and Variables　348

4.9.2　ping6 Command: Send Queries　350

4.9.3　ping6 Command: Receive Replies　355

4.9.4　ping6 Command: Print Supported Qtypes　362

4.9.5　ping6 Command: Print Node Addresses　365

4.9.6　Query Processing: ni6_input() Function　367

4.9.7　Node Name Manipulation　376

4.9.8　Create Node Addresses Reply: ni6_store_addrs() Function　383

4.10　Node Information Operation　387

5　Neighbor Discovery and Stateless Address Autoconfiguration　389

5.1　Introduction　389

5.2　Neighbor Discovery Protocol Overview　390

5.3　Stateless Address Autoconfiguration Overview　391

5.4　ND Protocol Messages　392

5.5　Example Exchanges of ND Protocol Messages　393

5.6　ND Protocol Packet Types and Formats　395

5.6.1　Router Solicitation Message　396

5.6.2　Router Advertisement Message　397

5.6.3　Neighbor Solicitation Message　401

5.6.4　Neighbor Advertisement Message　402

5.6.5　Redirect Message　403

5.7　Neighbor Discovery Option Types and Formats　405

5.7.1　Link-Layer Address Options　405

5.7.2　Prefix Information Option　406

5.7.3　Redirected Header Option　407

5.7.4　MTU Option　407

5.7.5　Route Information Option　408

5.8　Next-Hop Determination and Address Resolution　410

5.9　Neighbor Unreachability Detection Algorithm　411

5.10　Stateless Address Autoconfiguration　412

5.10.1　Address Formation and Address States　413

5.10.2　Duplicate Address Detection Algorithm　415

5.10.3　Processing Router Advertisement　416

5.10.4　Privacy Extensions　417

5.11　Router Specific Operation　419

5.11.1　Sending Unsolicited Router Advertisements　422

5.11.2　Processing Router Solicitations　422

5.11.3　Processing Router Advertisements　423

5.12　Host Specific Operation　423

5.12.1　Sending Router Solicitations　423

5.12.2　Processing Router Advertisements　425

5.12.3　Default Router Selection　426

5.13　Code Introduction　426

5.13.1　ND Message Definitions　427

5.13.2　Neighbor Cache—llinfo_nd6{} Structure　429

5.13.3　Operational Variables—nd_ifinfo{} Structure　432

5.13.4　Default Router—nd_defrouter{} Structure　433

5.13.5　Prefix—nd_prefix{} Structure　434

5.13.6　Prefix Control—nd_prefixctl{} Structure　436

5.13.7　ND Message Options—nd_opts{} Structure　436

5.13.8　DAD Queue Entry—dadq{} Structure　437

5.13.9　IPv6 Address—in6_ifaddr{} Structure　438

5.13.10　Destination Cache　438

5.13.11　Operation Constants　438

5.14　Initialization Functions　439

5.14.1　nd6_init() Function　439

5.14.2　nd6_ifattach() Function　440

5.15　Neighbor Cache Management Functions　441

5.15.1　nd6_rtrequest() Function　441

5.15.2　nd6_cache_lladdr() Function　452

5.15.3　nd6_lookup() Function　463

5.15.4　nd6_free() Function　467

5.15.5　nd6_timer() Function　470

5.16　ND Protocol Messages Processing Functions　478

5.16.1　nd6_ns_output() Function　478

5.16.2　nd6_ns_input() Function　484

5.16.3　nd6_na_input() Function　493

5.16.4　nd6_na_output() Function　504

5.16.5　nd6_rs_input() Function　510

5.16.6　nd6_ra_input() Function　513

5.16.7　icmp6_redirect_input() Function　521

5.16.8　icmp6_redirect_output() Function　528

5.17　ND Protocol Message Options Processing Functions　536

5.17.1　nd6_option_init() Function　536

5.17.2　nd6_option() Function　536

5.17.3　nd6_options() Function　538

5.18　Default Router Management Functions　540

5.18.1　defrouter_addreq() Function　540

5.18.2　defrouter_delreq() Function　541

5.18.3　defrouter_addifreq() Function　542

5.18.4　defrouter_delifreq() Function　544

5.18.5　defrouter_lookup() Function　545

5.18.6　defrouter_select() Function　546

5.18.7　defrtrlist_del() Function　550

5.18.8　defrtrlist_update() Function　553

5.19　Prefix Management Functions　555

5.19.1　nd6_prelist_add() Function　555

5.19.2　prelist_remove() Function　557

5.19.3　prelist_update() Function　558

5.19.4　find_pfxlist_reachable_router() Function　568

5.19.5　Prefix and Address State about On-link Condition　568

5.19.6　pfxlist_onlink_check() Function　571

5.19.7　nd6_prefix_onlink() Function　575

5.19.8　nd6_prefix_offlink() Function　578

5.20　Stateless Address Autoconfiguration Functions　580

5.20.1　in6_ifadd() Function　580

5.20.2　in6_tmpifadd() Function　584

5.20.3　regen_tmpaddr() Function　588

5.21　Duplicate Address Detection Functions　590

5.21.1　nd6_dad_find() Function　590

5.21.2　nd6_dad_starttimer() Function　590

5.21.3　nd6_dad_stoptimer() Function　590

5.21.4　nd6_dad_start() Function　591

5.21.5　nd6_dad_stop() Function　594

5.21.6　nd6_dad_timer() Function　594

5.21.7　nd6_dad_duplicated() Function　598

5.21.8　nd6_dad_ns_output() Function　599

5.21.9　nd6_dad_ns_input() Function　600

5.21.10　nd6_dad_na_input() Function　601

5.22　Miscellaneous Functions　602

5.22.1　nd6_is_addr_neighbor() Function　602

5.22.2　nd6_output() Function　604

5.22.3　rt6_flush() Function　611

5.22.4　nd6_rtmsg() Function　612

6　Transport Layer Implications　615

6.1　Introduction　615

6.2　TCP and UDP over IPv6　616

6.3　Pseudo Header for IPv6　616

6.4　Checksum Difference between IPv4 and IPv6　617

6.5　IPv4-mapped IPv6 Address Usage　618

6.6　Code Introduction　618

6.6.1　Protocol Control Blocks for IPv6　618

6.7　General Operations on PCBs and Sockets　627

6.7.1　IPv6 PCB Allocation—in_pcballoc() Function　627

6.7.2　Bind Local Address—in6_pcbbind() Function　630

6.7.3　Fix Remote Address—in6_pcbconnect() Function　639

6.7.4　Function in6_pcbladdr()　642

6.7.5　Search for a PCB Entry—in6_pcblookup_local() Function　644

6.7.6　Search for IPv4-mapped PCB—in_pcblookup_local() Function　647

6.7.7　Search for a PCB Entry—in6_pcblookup_hash() Function　650

6.7.8　Search for IPv4-mapped PCB—in_pcblookup_hash() Function　651

6.7.9　Detach an IPv6 PCB—in6_pcbdetach() Function　653

6.7.10　Control Message Signaling—in6_pcbnotify() Function　655

6.7.11　Flush PCB Cached Route—in6_rtchange() Function　659

6.7.12　Retrieve Peer Address—in6_setpeeraddr() Function　660

6.7.13　Retrieve Local Address—in6_setsockaddr() Function　662

6.8　TCP-over-IPv6　663

6.8.1　TCP-over-IPv6 Instance of ip6protosw{}　663

6.8.2　TCP Output　663

6.8.3　Initializing Headers—tcp_fillheaders() Function　669

6.8.4　TCP Input—tcp6_input() and tcp_input() Functions　670

6.8.5　TCP Control Input—tcp6_ctlinput() Function　675

6.8.6　TCP User Requests　678

6.9　UDP-over-IPv6　685

6.9.1　UDP-over-IPv6 Instance of ip6protosw{}　685

6.9.2　UDP Output—udp6_output() Function　685

6.9.3　UDP Input—udp6_input() Function　692

6.9.4　UDP Control Input—udp6_ctlinput() Function　699

6.9.5　UDP User Requests Handling　702

6.10　Raw IPv6　709

6.10.1　Raw IPv6 Statistics　709

6.10.2　Raw IPv6 Output—rip6_output() Function　710

6.10.3　Raw IPv6 Input—rip6_input() Function　715

6.10.4　ICMPv6 Input—icmp6_rip6_input() Function　719

6.10.5　Raw IPv6 Control Input—rip6_ctlinput() Function　724

6.10.6　Raw IPv6 Control Output—rip6_ctloutput() Function　725

6.10.7　Raw IPv6 User Requests Handling　730

6.11　Summary of Operation with IPv4-mapped IPv6 Addresses　738

6.12　Viewing IPv6 Connections with netstat　743

6.13　Configuring IPv4-mapped IPv6 Address Support　745

7　Socket API Extensions　747

7.1　Introduction　747

7.2　The Basic Socket API—[RFC3493]　748

7.2.1　Basic Definitions　748

7.2.2　Interface Identification　749

7.2.3　IPv4 Communication over AF_INET6 Socket　750

7.2.4　Address and Name Conversion Functions　752

7.2.5　Basic Socket Options　760

7.3　The Advanced Socket API—[RFC3542]　764

7.3.1　Advanced Definitions　764

7.3.2　IPv6 Raw Sockets　766

7.3.3　Introduction to Ancillary Data　768

7.3.4　IPv6 Packet Information　770

7.3.5　Manipulation of IPv6 Extension Headers　773

7.3.6　Path MTU APIs　778

7.3.7　Socket Extensions for the “r” Commands　778

7.3.8　Summary Tables of Socket Options　780

7.4　Kernel Implementation of IPv6 Socket APIs　783

7.4.1　Code Introduction　783

7.4.2　ip6_pktopts{} Structure　786

7.4.3　IPv6 Socket Option Processing—ip6_ctloutput() Function　790

7.4.4　Getting Socket Options—ip6_getpcbopt() Function　805

7.4.5　Setting Socket Options and Ancillary Data　807

7.4.6　Cleaning Up—ip6_freepcbopts() Function　823

7.4.7　IPv6 Multicast Socket Options　824

7.4.8　IPv6 Raw Socket Options—ip6_raw_ctloutput() Function　835

7.4.9　ICMPv6 Socket Options—icmp6_ctloutput() Function　838

7.4.10　Delivering Incoming Information—ip6_savecontrol() Function　840

7.5　Socket Options and Ancillary Data Examples　848

7.5.1　Example of the Send Path　848

7.5.2　Example of the Receive Path　850

7.6　Implementation of Library Functions—libinet6　853

7.6.1　inet_pton() and inet_pton6() Functions　853

7.6.2　inet_ntop() and inet_ntop6() Functions　859

7.6.3　getaddrinfo() Function　863

7.6.4　Address Ordering Examples　888

7.6.5　freeaddrinfo() Function　895

7.6.6　gai_strerror() Function　897

7.6.7　getnameinfo() Function　898

7.6.8　Other Library Functions　906

References　909

Index　915

About the Authors　938