IPv6 Core Protocols Implementation

Transcription

1 IPv6 Core Protocols Implementation Qing Li Blue Coat Systems, Inc. Tatuya Jinmei Toshiba Corporation Keiichi Shima Internet Initiative Japan, Inc. ii.x'l J ELSEVIER AMSTERDAM BOSTON HEIDELBERG LONDON NEW YORK OXFORD PARIS SAN DIEGO SAN FRANCISCO SINGAPORE SYDNEY TOKYO Morgan Kaufmann Publishers is an imprint of Elsevier II»> I L '4 MORGAN KAUFMANN PUBLISHERS

2 Contents Foreword xix Preface xxi About the Authors xxix Introduction Introduction A Brief History of IPv6 and КАМЕ Commercial Success of КАМЕ Overview of the КАМЕ Distribution Source Tree Structure Build Procedure Overview of BSD Network Implementation Source Code Narrations Typographical Conventions Sample Source Code Description Preprocessor Variables Networking Device and Architecture Assumptions 1.6 Mbufs and IPv Common Mbuf Manipulation Macros and Functions Mbuf Tagging Mbuf Requirement for IPv Diagnosing Mbuf Chain 26

3 IPv6 Addressing Architecture Introduction IPv6 Addresses Textual Representation of IPv6 Addresses Address Scopes Scope Zones Zone Indices Textual Representation of Scoped Addresses Deprecation of Unicast Site-local Addresses IPv6 Address Format Interface Identifier Generation Notes about Address Format Multicast Address Format Node Address Requirements IPv6 Address Space Management Code Introduction IPv6 Address Structures in6_addr{} and sockaddr_in6{} Macros and Variables Handling Scope Zones Initialization of Scope Zones Scope Zone IDs Zone IDs in Address Structures Scope-Related Utility Functions Interface Address Structures ifaddr{} and in6_ifaddr{ } Structures in6_ifreq{ } and in6_aliasreq{ } Structures Multicast Address Structures IPv6 Prefix Structure Overview of Address Manipulation Routines Interface Initialization for IPv in6_if_up () Function in6_if attach () Function in6_if attach_loopback () Function in6_ifattach_linklocal () Function get_ifid() Function get_hw_ifid() Function get_rand_if id () Function in6if_do_dad() Function 94 Contents

4 Contents 2.14 IPv6 Interface Address Configuration in6_control () Function in6_update_if a () Function in6_joingroup () and in6_leavegroup () Functions in6_addmulti () and in6_delmulti () Functions in6_ifinit () Function in6_if addloop () and in6_if loop_request () Functions Deleting an IPv6 Address in6_purgeaddr () Function in6_ifremloop () Function in6_unlink_ifa () Function Operation with Address Configuration Utility 127 Internet Protocol version Introduction IPv6 Header Format Comparison to the IPv4 Header IPv6 Extension Headers Order of Extension Headers Hop-by-Hop Options Header Destination Options Header Routing Header Fragment Header IPv6 Options Source Address Selection Default Address Selection Source Address Selection Destination Address Selection Code Introduction Statistics Header Structures ip6protosw{ } Structure IPv6 Packet Address Information in Mbuf l ip6_setdstifaddr () Function ip6_getdstif addr () Function 162

5 x Contents ip6_setpktaddrs () Function 1бЗ ip6_getpktaddrs () Function Input Processing: ip6_input () Function Processing Hop-by-Hop Options Header: ip6_hopopts_input () Function Processing Each Option: ip6_process_hopopts () Function Processing Unknown Option: ip6_unknown_opt () Function Processing Destination Options Header: dest6_input () Function Reassembling Fragmented Packets Structures for Packet Reassembly frag6_input () Function Processing Routing Header: route6_input () Function Forwarding: ip6_forward () Function Output Processing Source Address Selection in6_selectsrc () Function Route Selection: ip6_selectroute () Function ip6_output() Function Make Extension Headers: ip6_copyexthdr () Function Split Headers: ip6_splithdr () Function Insert Jumbo Payload Option: ip6_insert_jumboopt () Function Fragmentation: ip6_insertfraghdr () Function Path MTU Determination: ip6_getpmtu () Function Multicast Loopback: ip6_mloopback () Function 285 Internet Control Message Protocol for IPv Introduction ICMPv6 Message Destination Unreachable Message Packet Too Big Message Time Exceeded Message Parameter Problem Message Echo Request Message 294

6 Contents Echo Reply Message ICMPv6 Message Processing Rules Path MTU Discovery Mechanism Node Information Query Node Information Message Format NOOP Query Supported Qtypes Query Node Name Query Node Addresses Query IPv4 Addresses Query Code Introduction Statistics ICMPv6 Header ICMPv6 Input Processing icmp6_input () Function Notifying Errors: icmp6_notify_error () Function Path MTU Discovery Implementation icmp6_mtudisc_update () Function ICMPv6 Output Processing Sending Error: icmp6_error () Function Error Rate Limitation: icmp6_r ate limit () Function icmp6_ref lect () Function Node Information Query Implementation Types and Variables ping6 Command: Send Queries ping6 Command: Receive Replies ping6 Command: Print Supported Qtypes ping6 Command: Print Node Addresses Query Processing: ni6_input () Function Node Name Manipulation Create Node Addresses Reply: ni6_store_addrs () Function Node Information Operation 387 Neighbor Discovery and Stateless Address Autoconfiguration Introduction Neighbor Discovery Protocol Overview 390

7 xii Contents 5.3 Stateless Address Autoconfiguration Overview ND Protocol Messages Example Exchanges of ND Protocol Messages ND Protocol Packet Types and Formats Router Solicitation Message Router Advertisement Message Neighbor Solicitation Message Neighbor Advertisement Message Redirect Message Neighbor Discovery Option Types and Formats Link-Layer Address Options Prefix Information Option Redirected Header Option MTU Option Route Information Option Next-Hop Determination and Address Resolution Neighbor Unreachability Detection Algorithm Stateless Address Autoconfiguration Address Formation and Address States Duplicate Address Detection Algorithm Processing Router Advertisement 4l Privacy Extensions Router Specific Operation Sending Unsolicited Router Advertisements Processing Router Solicitations Processing Router Advertisements Host Specific Operation Sending Router Solicitations Processing Router Advertisements Default Router Selection Code Introduction ND Message Definitions Neighbor Cache 11 inf o_nd6 {} Structure З.З Operational Variables nd_ifinfo{} Structure Default Router nd_de f rout er {} Structure Prefix nd_prefix{} Structure Prefix Control nd_prefixctl{} Structure ND Message Options nd_opts{} Structure DAD Queue Entry dadq{ } Structure 437

8 IPv6 Address in6_ifaddr{ } Structure Destination Cache Operation Constants Initialization Functions nd6_init () Function nd6_ifattach() Function Neighbor Cache Management Functions nd6_rtrequest () Function nd6_cache_lladdr () Function nd6_lookup () Function nd6_free() Function nd6_timer() Function ND Protocol Messages Processing Functions nd6_ns_output () Function nd6_ns_input () Function nd6_na_input () Function nd6_na_output () Function nd6_rs_input () Function nd6_ra_input () Function icmp6_redirect_input () Function icmp6_redirect_output () Function ND Protocol Message Options Processing Functions nd6_option_init () Function nd6_option() Function nd6_options () Function Default Router Management Functions defrouter_addreq() Function defrouter_delreq() Function defrouter_addifreq () Function defrouter_delifreq () Function defrouter_lookup () Function def router_select () Function defrtrlist_del () Function defrtrlist_update () Function Prefix Management Functions nd6_prelist_add () Function prelist_remove () Function З prelist_update () Function 558

9 XIV Contents find_pfxlist_reachable_router () Function Prefix and Address State about On-link Condition pfxlist_onlink_check () Function nd6_pref ix_onlink () Function I9.8 nd6_prefix_offlink() Function Stateless Address Autoconfiguration Functions in6_ifadd() Function in6_tmpifadd () Function regen_tmpaddr () Function Duplicate Address Detection Functions nd6_dad_f ind () Function nd6_dad_starttimer () Function nd6_dad_stoptimer () Function nd6_dad_start () Function nd6_dad_stop () Function nd6_dad_timer () Function nd6_dad_duplicated () Function nd6_dad_ns_output () Function nd6_dad_ns_input () Function nd6_dad_na_input () Function Miscellaneous Functions nd6_is_addr_neighbor () Function nd6_output () Function rt6_flush() Function 6ll nd6_rtmsg() Function 612 Transport Layer Implications Introduction TCP and UDP over IPv6 6l6 6.3 Pseudo Header for IPv6 6l6 6.4 Checksum Difference between IPv4 and IPv IPv4-mapped IPv6 Address Usage Code Introduction Protocol Control Blocks for IPv General Operations on PCBs and Sockets IPv6 PCB Allocation in_pcballoc () Function Bind Local Address in6_pcbbind () Function Fix Remote Address in6_pcbconnect () Function 639

10 Contents xv Function in6_pcbladdr () Search for a PCB Entry in6_pcblookup_local () Function Search for IPv4-mapped PCB in_pcblookup_local () Function Search for a PCB Entry in6_pcblookup_hash () Function Search for IPv4-mapped PCB in_pcblookup_hash () Function Detach an IPv6 PCB in6_pcbdetach () Function Control Message Signaling in6_pcbnotify () Function Flush PCB Cached Route in6_rtchange () Function Retrieve Peer Address in6_setpeeraddr () Function Retrieve Local Address in6_setsockaddr () Function TCP-over-IPv TCP-over-IPv6 Instance of ip6protosw{ } TCP Output Initializing Headers tcp_f illheaders () Function TCP Input tcp6_input () and tcp_input () Functions TCP Control Input tcp6_ctlinput () Function TCP User Requests UDP-over-IPv UDP-over-IPv6 Instance of ip6protosw{} UDP Output udp6_output () Function UDP Input udp6_input () Function UDP Control Input udp6_ctlinput () Function UDP User Requests Handling Raw IPv Raw IPv6 Statistics Raw IPv6 Output rip6_output () Function Raw IPv6 Input rip6_input () Function ICMPv6 Input icmp6_rip6_input () Function Raw IPv6 Control Input rip6_ctlinput () Function 724

11 Raw IPv6 Control Output rip6_ctloutput () Function Raw IPv6 User Requests Handling Summary of Operation with IPv4-mapped IPv6 Addresses Viewing IPv6 Connections with netstat Configuring IPv4-mapped IPv6 Address Support 745 Socket API Extensions Introduction The Basic Socket API [RFC Basic Definitions Interface Identification IPv4 Communication over AF_INET6 Socket Address and Name Conversion Functions Basic Socket Options The Advanced Socket API [RFC3542] Advanced Definitions IPv6 Raw Sockets Introduction to Ancillary Data IPv6 Packet Information Manipulation of IPv6 Extension Headers Path MTU APIs Socket Extensions for the "r" Commands Summary Tables of Socket Options Kernel Implementation of IPv6 Socket APIs Code Introduction ip6_pktopts{ } Structure IPv6 Socket Option Processing ip6_ctloutput () Function Getting Socket Options ip6_getpcbopt () Function Setting Socket Options and Ancillary Data Cleaning Up ip6_freepcbopts () Function IPv6 Multicast Socket Options IPv6 Raw Socket Options ip6_raw_ctloutput () Function ICMPv6 Socket Options icmp6_ctloutput () Function 838

12 Contents xvii Delivering Incoming Information ip6_savecontrol () Function Socket Options and Ancillary Data Examples Example of the Send Path Example of the Receive Path Implementation of Library Functions libinet inet_pton() and inet_pton6 () Functions inet_ntop() and inet_ntop6 () Functions getaddrinf о () Function Address Ordering Examples freeaddrinfo () Function gai_strerror() Function getnameinfo () Function Other Library Functions 906 References 909 Index 915